Double container, method for producing same, and container production method

Abstract

Provided is a double container in which an inner bag can be easily removed from a container body, and a closed space can be easily formed between an outer shell and the inner bag.　The present invention provides a double container comprising a container body and a mouth portion attachment member attached to the mouth portion of the container body, wherein: the container body includes an inner bag and an outer shell that is disposed to cover the inner bag; the inner bag includes a protrusion that protrudes from the opening edge of the outer shell; the mouth portion attachment member includes a body member that is engaged with the protrusion in the axial direction, in which the central axis of the mouth portion of the container body extends; the body member includes a discharge port which communicates with the inside of the inner bag or an insertion hole into which the protrusion is inserted; and the body member and the outer shell adhere to each other at the adhesion surface directly or via another member. The double container according to the present invention has excellent recyclability, and thus can be suitably used in production of recycle materials.

Description

Double container and its manufacturing method, and container manufacturing method

[0001] The present invention relates to a double-layered container and a method for manufacturing the same, and a method for manufacturing the container by biaxially stretched blow molding.

[0002] (First Aspect) Patent Document 1 discloses a double container including a container body having an outer shell and an inner bag, and the double container is configured so that the inner bag can be pulled out from the container body by gripping a mouth attachment member that engages with the inner bag.

[0003] (Second Aspect) Patent Document 2 discloses a method for manufacturing a container by biaxially stretching and blow molding a preform.

[0004] JP 2024-18821 A JP 2019-130735 A

[0005] (First aspect) In the double container of Patent Document 1, the mouth attachment member is engaged only with the inner bag, which has the advantage that the inner bag can be pulled out simply by pulling the mouth attachment member. However, there is a problem in that a gap is likely to form between the inner bag and the outer shell at the mouth of the container body, making it difficult to use in applications where it is necessary to form an airtight space between the outer shell and the inner bag.

[0006] The present invention has been made in consideration of the above circumstances, and aims to provide a double container in which the inner bag can be easily pulled out from the container body and an airtight space can be easily formed between the outer shell and the inner bag.

[0007] (Second Aspect) In one example, biaxial stretch blow molding is performed by placing a blow core inside a preform and blowing air through through holes provided in the blow core. Generally, the blow core abuts on the inner peripheral surface of the preform or has a shape that makes the gap between the blow core and the inner peripheral surface of the preform very small, thereby suppressing air leakage from the gap between the preform and the blow core.

[0008] In some cases, a sealing member is welded to the open end of a container to close the open end. In this case, a tapered portion is sometimes provided at the open end of the container by bending the outer circumferential surface of the container adjacent to the open end radially inward to ensure an area for welding the sealing member.

[0009] When a container having such a reduced diameter portion is formed by biaxial stretch blow molding, the preform and the blow core come into contact or are close to each other only at the inner peripheral surface of the reduced diameter portion. However, since the area of ​​this inner peripheral surface is very small, there is a problem in that air is likely to leak from the gap between the preform and the blow core.

[0010] The present invention has been made in consideration of these circumstances, and provides a technology that can suppress air leakage from the gap between the preform and the blow core when manufacturing a container body having a reduced diameter portion at the opening end by biaxial stretch blow molding.

[0011] (First Aspect) According to the present invention, the following inventions are provided: [1] A double container comprising a container body and a mouth attachment member attached to the mouth of the container body, wherein the container body comprises an inner bag and an outer shell arranged to cover the inner bag, the inner bag having a protrusion protruding from the open end of the outer shell, and wherein, when the direction of the central axis of the mouth of the container body is defined as the axial direction, the mouth attachment member comprises a main body member that engages with the protrusion in the axial direction, and the main body member has a discharge port that communicates with the interior of the inner bag or an insertion hole through which the protrusion is inserted, and the main body member and the outer shell are in close contact with each other at their contact surfaces, either directly or via another member. [2] The double container according to [1], wherein the main body member comprises a main body member sealing tube, and the main body member sealing tube and the outer shell are in close contact with each other at their contact surfaces, either directly or via another member. [3] The double container according to [2], wherein the contact surface is inclined with respect to the axial direction. [4] The double container according to [2] or [3], wherein the main body member comprises an engaging tube, and the engaging tube has an engaging protrusion that engages with the protrusion in the axial direction, and the engaging tube and the main body member sealing tube are connected to each other at a position farther from the tip of the engaging tube than the engaging protrusion. [5] The double container according to any one of [2] to [4], wherein the main body member sealing tube does not engage with the outer shell in a concave-convex manner. [6] The double container according to any one of [2] to [5], wherein the outer shell comprises an outer shell sealing tube, and the contact surface is disposed on the outer shell sealing tube. [7] The double container according to [6], wherein the contact surface is a surface where the outer peripheral surface of the main body member sealing tube and the inner peripheral surface of the outer shell sealing tube come into close contact. [8] The double container according to any one of [2] to [7], wherein the main body member has an inner tube having an outer diameter smaller than that of the main body member sealing tube, and the inner peripheral surface of the inner tube is in close contact with the outer peripheral surface of the protrusion. [9] The double container according to [8], wherein the contact surface between the inner peripheral surface of the inner tube and the outer peripheral surface of the protrusion is inclined with respect to the axial direction.

[10] The double container according to any one of [2] to [9], wherein the main body member has an insertion hole through which the protruding portion is inserted, the spout attachment member has a discharge member having a discharge port communicating with the interior of the inner bag, and the discharge member is attached to the tip of the protruding portion that protrudes from the main body member through the insertion hole.

[11] The double container according to [2], wherein the contact surface is a surface where the outer peripheral surface of the main body member sealing tube and the inner peripheral surface of the outer shell are in close contact.

[12] The double container according to [2], wherein the contact surface is provided at the tip of the main body member sealing tube.

[13] The double container according to

[11] or

[12] , wherein the main body member sealing tube has a soft portion made of elastomer integrally molded therewith so as to include the contact surface.

[14] The double container according to [1], wherein the separate member is a soft member made of elastomer, and the soft member is disposed between the open end of the outer shell and the main body member.

[15] The double container according to

[12] or

[14] , wherein the main body member and the outer shell are screwed together.

[16] The double container according to [2], wherein the contact surface is provided in a region adjacent to the open end of the outer shell.

[17] The double container according to

[16] , wherein the main body member sealing tube engages with the outer shell at a position farther from the open end of the outer shell than the contact surface.

[18] The double container according to

[16] , wherein the region adjacent to the tip of the main body member sealing tube and the region adjacent to the open end of the outer shell are in close contact with each other at the contact surface.

[19] The double container according to any one of

[16] to

[18] , wherein at least one of the outer shell and the main body member sealing tube has a plurality of annular protrusions arranged along the axial direction at the contact surface.

[20] The method for manufacturing the double container according to any one of [1] to

[19] , wherein the container body of the double container is manufactured by biaxial stretch blow molding.

[0012] (Second Aspect) According to the present invention, the following inventions are provided: [1] A method for manufacturing a container, comprising a biaxially stretched blow molding step and a cutting step, wherein in the biaxially stretched blow molding step, the preform is biaxially stretched blow molded in a state in which the preform is attached to a blow core such that an insert portion of the blow core is disposed within the preform, the preform has a tubular extension portion extending from a portion corresponding to an open end of a container body of the container, the insert portion is inserted into the extension portion, and in the cutting step, the extension portion is cut off after the biaxially stretched blow molding step. [2] The method according to [1], wherein the open end after the cutting step is provided with a reduced diameter portion configured by bending an outer circumferential surface adjacent to the open end radially inward, and the method comprises a content filling step and a sealing step in this order after the cutting step, wherein the content filling step fills the container body with content, and the sealing step closes an opening at the open end by welding a seal member to an upper surface of the reduced diameter portion. [3] The method according to [1] or [2], wherein the inner peripheral surface of the extension portion and the outer peripheral surface of the insertion portion are brought into contact with or close to each other. [4] The method according to any one of [1] to [3], wherein the preform is formed by covering an outer preform with an inner preform, the inner preform having a protrusion protruding from an open end of the outer preform, and the extension portion is provided on the protrusion.

[0013] In the present invention, the main body member of the spout-attaching member engages with the inner bag in the axial direction, making it easy to pull out the inner bag from the container body. Also, the main body member and the outer shell are in close contact with each other at their contact surfaces, making it easy to form a sealed space between the outer shell and the inner bag.

[0014] (Second Aspect) In the method of the present invention, the preform has a cylindrical extension extending from a portion corresponding to the open end of the container body, and the insert portion of the blow core is inserted into the extension. Since the extension can be formed into any shape, by adopting a configuration in which the insert portion of the blow core is inserted into the extension, it is possible to suppress air leakage during biaxial stretch blow molding.

[0015] (First aspect) A perspective view of a double container 1 according to a first embodiment of the present invention. The dashed-dotted lines in the figures represent boundary lines where the curvature of the surfaces constituting the surface shape changes. This also applies to other figures. An exploded perspective view of the double container 1 of FIG. 1. A cross-sectional view of the vicinity of the mouth 5 of the double container 1 of FIG. 1. An exploded view of FIG. 3. An exploded view of the container body 2 of FIG. 4. A perspective view showing a state in which the inner preform 14 and the outer preform 13 are separated. A perspective view of a preform 15 formed by covering the inner preform 14 with the outer preform 13. A cross-sectional view corresponding to FIG. 3 of a double container 1 according to a second embodiment of the present invention. An exploded view of FIG. 8. A cross-sectional view corresponding to FIG. 3 of a double container 1 according to a third embodiment of the present invention. This view shows a state in which the discharge member 43 has been separated from the state of FIG. 10. This view shows a state in which the main body member 41 and the seal member 44 have been separated from the state of FIG. 11. This view shows a cross-sectional view corresponding to FIG. 3 of a double container 1 according to a fourth embodiment of the present invention. This view shows a state in which the discharge member 43 has been separated from the state of FIG. 13. This view shows a state in which the main body member 41 and the seal member 44 have been separated from the state of FIG. 14. 3A and 3B are cross-sectional views of a double container 1 according to a fifth embodiment of the present invention, corresponding to FIG. 3. FIG. 16 is an exploded view of FIG. 16. FIG. 16 is a cross-sectional view of a double container 1 according to a sixth embodiment of the present invention, corresponding to FIG. 3. FIG. 18 is an exploded view of FIG. 18. FIG. 16 is a cross-sectional view of a double container 1 according to a first modified example of the sixth embodiment of the present invention, corresponding to FIG. 3. FIG. 20 is an exploded view of FIG. 20. FIG. 20 is a cross-sectional view of a double container 1 according to a second modified example of the sixth embodiment of the present invention, corresponding to FIG. 3. FIG. 22 is an exploded view of a double container 1 according to a seventh embodiment of the present invention, corresponding to FIG. 3. FIG. 24 is an exploded view of a double container 1 according to an eighth embodiment of the present invention, corresponding to FIG. 3. FIG. 26 is an exploded view of FIG. 26. FIG. 20 is a cross-sectional view of a double container 1 according to a ninth embodiment of the present invention, corresponding to FIG. 3. FIG. 28 is an exploded view of FIG. 28. FIGs. 30A and 30B are enlarged views of regions A and B in FIG. 29, respectively. (Second aspect) A front view of a container 10 according to a first embodiment of the present invention. FIG. 31 is an exploded view of the container 10 in FIG. 31. A cross-sectional view of the vicinity of the mouth 5 of the container 10 in FIG. 31. A cross-sectional view showing a state in which the discharge member 43 has been separated from the state shown in FIG. 33. 35 is a cross-sectional view showing a state in which the main body member 41 is separated from the state shown in FIG. 34.Fig. 1 is a cross-sectional view showing a state in which the inner preform 14 and the outer preform 13 are separated. Fig. 2 is a cross-sectional view of the preform 15 and the blow core 21. Fig. 3 is a cross-sectional view showing a state in which the preform 15 is attached to the blow core 21 and brought close to the heater 32. Fig. 4 is a cross-sectional view for explaining biaxial stretch blow molding of the preform 15. Fig. 5 is a cross-sectional view of a molded body 2b obtained by biaxial stretch blow molding. Fig. 6 is a cross-sectional view showing a comparative form preform 15X and the blow core 21.

[0016] Hereinafter, embodiments of the present invention will be described. Various features shown in the following embodiments can be combined with each other. Each feature can be an invention independently. In the following embodiments, elements not specified in the claims are optional elements and can be omitted. Any number of "0"s (for example, one or two) may be added to the end of numerical values ​​disclosed in the following description. For example, one or two "0"s may be added after "1.4" to make it "1.40" or "1.400".

[0017] (First Aspect) 1. First Embodiment A double-sided container 1 according to a first embodiment of the present invention will be described using Figures 1 to 7. In the following description, terms relating to directions, such as "upper" and "lower," refer to directions when the bottom 7 is in contact with the ground. Furthermore, in the following description, the "axial direction" refers to the direction in which the central axis C (shown in Figure 2) of the mouth 5 extends, for example, the direction in which the inner bag 4 is pulled out from the container body 2. The "circumferential direction" refers to the direction of rotation about the central axis C of the mouth 5, for example, the direction in which the inner bag 4 is rotated at the mouth 5 relative to the outer shell 3. Unless otherwise specified, "clockwise" and "counterclockwise" refer to directions as viewed from the top of the double-sided container 1.

[0018] 1. Structure of double container 1 As shown in Fig. 1, the double container 1 of the first embodiment of the present invention comprises a container body 2 and a spout attachment member 8. Each component will be described in detail below.

[0019] <Basic Structure of Container Body 2> As shown in Fig. 2, the container body 2 has a mouth 5, a body 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.

[0020] The body 6 is disposed adjacent to the mouth 5 on a side farther from the open end 5c than the mouth 5. The body 6 preferably has a larger outer diameter (in this specification, "outer diameter" means the equivalent circular 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.

[0021] 3 to 5, the container body 2 includes an inner bag 4 and an outer shell 3 disposed 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.

[0022] <Detailed Structure of Outer Shell 3 and Inner Bag 4> As shown in Figures 3 to 5, the inner bag 4 has a protruding portion 4c that protrudes from the open end 3a of the outer shell 3. As shown in Figure 4, the protruding portion 4c of the inner bag 4 has, in order from the open end 3c side, an expanded diameter portion 4c1, a reduced diameter portion 4c2, and an engaging portion 4c3. The reduced diameter portion 4c2 has a smaller inner diameter than the expanded diameter portion 4c1 and the engaging portion 4c3. The outer shell 3 has, in order from the open end 3a side, first and second flange portions 3f1 and 3f2. An outer shell seal tube 3g is provided on the first flange portion 3f1.

[0023] 5 , the inner bag 4 includes a first tube 4a and a second tube 4b. The first tube 4a is disposed within the outer shell 3. The second tube 4b has a larger outer diameter than the first tube 4a and is disposed closer to the open end 5c of the inner bag 4 than the first tube 4a. The entire second tube 4b may be disposed outside the outer shell 3, or part or all of the second tube 4b may be disposed within the outer shell 3, with the remainder disposed outside the outer shell 3.

[0024] The lower surface 4b4 of the second tube 4b abuts against the outer shell 3. The lower surface 4b4 abuts against an inner bag support surface 3a3 provided on the outer shell 3. Support of the lower surface 4b4 by the inner bag support surface 3a3 prevents the inner bag 4 from falling into the outer shell 3. The inner bag support surface 3a3 may be flush with the opening end 3a (more specifically, the base surface 3a1 of the opening end 3a), or may be provided at a higher or lower position than the opening end 3a (more specifically, the base surface 3a1). In this embodiment, the inner bag support surface 3a3 is provided at a lower position than the opening end 3a (more specifically, the base surface 3a1). Therefore, a portion of the second tube 4b is disposed inside the outer shell 3, and the remainder is disposed outside the outer shell 3.

[0025] As shown in Patent Document 1, a cam mechanism is preferably provided between the inner bag 4 and the outer shell 3. The cam mechanism functions to displace the inner bag 4 in a direction that allows it to be removed from the container body 2 by rotating the inner bag 4 clockwise or counterclockwise relative to the outer shell 3. This cam mechanism can be configured, for example, by a ridge 4g provided on the outer peripheral surface of the inner bag 4 and a cam rail 3l provided on the inner peripheral surface of the outer shell 3 (see FIG. 16). When the inner bag 4 is rotated relative to the outer shell 3 at the opening 5, the inner bag 4 is twisted and its diameter is reduced, making it easier to pull out the inner bag 4.

[0026] <Mouth mounting member 8> The mouth mounting member 8 is a member that is attached to the mouth 5 of the container body 2. In this embodiment, the mouth mounting member 8 is a cap 8a, but it may also be another member such as a pump. In this embodiment, the mouth mounting member 8 is configured to be attached to the mouth 5 in a stoppered manner, but it may also be configured to be attached to the mouth 5 in a screwed manner.

[0027] As shown in Figures 3 and 4, the mouth-attached member 8 includes a main body member 41. The main body member 41 includes a nozzle 41a, an inner tube 41b, an engaging tube 41c, a main body member sealing tube 41d, and an outer tube 41e. The outer diameters of these cylindrical portions increase in this order. Therefore, the inner tube 41b has a smaller outer diameter than the main body member sealing tube 41d. These cylindrical portions are connected to each other by a top surface 41g. The nozzle 41a is provided with a discharge port 41f that communicates with the interior of the inner bag 4, allowing the contents of the inner bag 4 to be discharged through the nozzle 41a and the discharge port 41f. The nozzle 41a is provided with a discharge valve 42. The discharge valve 42 is configured to allow the contents to be discharged while preventing outside air from entering the inner bag 4. The discharge port 41f can be closed with an overcap 46 (shown in FIG. 16), and when in use, the overcap 46 can be removed to open the discharge port 41f and allow the contents to be discharged.

[0028] The inner tube 41b is inserted into the inner bag 4, and the outer peripheral surface of the inner tube 41b is tightly fitted to the inner peripheral surface of the reduced diameter portion 4c2. This prevents the contents from leaking through a gap between the main body member 41 and the inner bag 4, and prevents outside air from entering the inner bag 4 through this gap. Note that instead of forming a seal by fitting the inner tube 41b to the inner bag 4, a seal may be formed using another method. For example, the seal may be formed by placing a packing between the opening end 5c and the main body member 41.

[0029] The engagement tube 41c has an engagement protrusion 41c1 on its inner circumferential surface. The engagement protrusion 41c1 is, for example, annular. The engagement protrusion 41c1 axially engages with the protrusion 4c (more specifically, with the engagement portion 4c3), thereby axially engaging the main body member 41 with the protrusion 4c. Preferably, the engagement tube 41c also circumferentially engages with the protrusion 4c. In this case, the protrusion 4c can be rotated in conjunction with the rotation of the main body member 41. In one example, the engagement tube 41c circumferentially engages with the protrusion 4c by uneven or frictional engagement between the inner circumferential surface of the engagement tube 41c and the outer circumferential surface of the engagement portion 4c3 at a position closer to the discharge port 41f than the engagement protrusion 41c1. In another example, the engagement tube 41c may be circumferentially engaged with the protrusion 4c by uneven or frictional engagement between the engagement protrusion 41c1 and the protrusion 4c at a portion 4c4 below the engagement portion 4c3.

[0030] As shown in Figures 3 and 4, the main body member seal tube 41d and the outer shell 3g are in close contact with each other at the contact surface 51. More specifically, the outer peripheral surface 41d1 of the main body member seal tube 41d and the inner peripheral surface 3g1 of the outer shell seal tube 3g are in close contact with each other at the contact surface 51. In this case, the contact surface 51 is disposed on the outer shell seal tube 3g. The contact surface 51 is preferably inclined with respect to the axial direction (i.e., non-parallel to the axial direction). Furthermore, the contact surface 51 is preferably inclined so as to open upward. This inclination angle is, for example, 0.5 to 10 degrees (2 degrees in this embodiment), and preferably 1 to 6 degrees. Specific examples of this inclination angle include 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6, 7, 8, 9, and 10 degrees, and may be within a range between any two of the values ​​exemplified here.

[0031] The inner circumferential surface 3g1 is inclined so that its diameter increases toward the tip 3g2 of the outer shell seal tube 3g. This facilitates the outer circumferential surface 41d1 to be tightly attached to the inner circumferential surface 3g1. Furthermore, when the outer circumferential surface 41d1 is tightly attached to the inner circumferential surface 3g1, a tight contact surface 51 is formed. When the outer circumferential surface 41d1 is not pressed against the inner circumferential surface 3g1, the outer circumferential surface 41d1 and the inner circumferential surface 3g1 may be parallel or non-parallel. Even if they are non-parallel, pressing the outer circumferential surface 41d1 against the inner circumferential surface 3g1 changes the inclination angle of at least one of the outer circumferential surface 41d1 and the inner circumferential surface 3g1, thereby allowing the two surfaces to be tightly attached to each other. Typically, the outer shell 3 is thicker than the main body member 41 and / or is made of a material with higher rigidity than the main body member 41, so the outer shell 3 has higher rigidity than the main body member 41. Therefore, pressing the outer circumferential surface 41d1 against the inner circumferential surface 3g1 mainly changes the inclination angle of the outer circumferential surface 41d1.

[0032] The engagement tube 41c and the main body member sealing tube 41d are connected to each other at a position closer to the discharge port 41f in the axial direction than the engagement protrusion 41c1 (i.e., at a position above the engagement protrusion 41c1). More specifically, the engagement tube 41c and the main body member sealing tube 41d are connected to each other at the top surface 41g. In other words, the engagement tube 41c and the main body member sealing tube 41d are connected to each other at a position farther from the tip 41c2 of the engagement tube 41c than the engagement protrusion 41c1. This configuration allows the engagement tube 41c and the main body member sealing tube 41d to deform independently of each other, which has the advantage that, for example, deformation of the engagement tube 41c during engagement does not affect the tight contact of the main body member sealing tube 41d.

[0033] The main body member sealing tube 41d does not engage with the outer shell 3 in a convex-concave manner. Because the main body member sealing tube 41d and the outer shell 3 are in close contact with each other, they are frictionally engaged, but the convex portions of one do not fit into the concave portions of the other. This allows the main body member sealing tube 41d to be quickly removed from the outer shell, suppressing an increase in the force required to pull out the inner bag 4. Furthermore, because the contact surface 51 is inclined to prevent undercuts, the contact at the contact surface 51 can be broken by slightly moving the main body member 41 away from the outer shell 3. This suppresses an increase in the force required to pull out the inner bag 4 due to friction at the contact surface 51.

[0034] The outer cylinder 41e is positioned so as to cover the outer shell seal cylinder 3g (i.e., outside the outer shell seal cylinder 3g). The tip 41e1 of the outer cylinder 41e is positioned close to the second flange portion 3f2. The outer peripheral surface of the outer cylinder 41e is flush with the outer peripheral surface of the second flange portion 3f2. This configuration improves the aesthetic appearance of the double container 1.

[0035] <Uses of the Double Container 1> In this embodiment, the discharge valve 42 is provided in the opening attachment member 8, so that the inner bag 4 contracts as the contents of the inner bag 4 are discharged. Furthermore, by providing an air inlet hole that allows outside air to enter the intermediate space between the outer shell 3 and the inner bag 4, a peelable container can be created in which the inner bag 4 separates from the outer shell 3 and contracts as the contents are discharged. The air inlet hole may be provided in either the outer shell 3 or the opening attachment member 8. Furthermore, an air inlet valve may be provided in the air inlet hole to allow outside air to enter the intermediate space while suppressing the discharge of outside air from the intermediate space. In this case, compressing the outer shell 3 increases the pressure in the intermediate space, allowing the contents to be discharged from the inner bag 4. When the compressive force on the outer shell 3 is removed and the outer shell 3 returns to its original shape, the introduction of outside air into the intermediate space allows the outer shell 3 to quickly restore its original shape. This configuration makes it possible to realize a squeeze-type peelable container. The double container 1 of this embodiment has the feature that an airtight space can be easily formed between the outer shell 3 and the inner bag 4, so it is preferable to use a squeeze-type peelable container.

[0036] <Removing the inner bag 4> Because the main body member 41 is axially engaged with the protrusion 4c, the inner bag 4 can be removed from the container body 2 by pulling the main body member 41. Furthermore, if the main body member 41 is also circumferentially engaged with the protrusion 4c, the inner bag 4 can be twisted and reduced in diameter by rotating the main body member 41. Since the inner bag 4 is less likely to rotate relative to the outer shell 3 at the body 6 and bottom 7 than at the mouth 5, rotating the inner bag 4 relative to the outer shell 3 at the mouth 5 twists the inner bag 4 and reduces its diameter. This reduces the force required to remove the inner bag 4.

[0037] Furthermore, if a cam mechanism is provided between the inner bag 4 and the outer shell 3, the inner bag 4 is configured to move in a direction that causes it to come out of the container body 2 as it rotates. With this configuration, by rotating the opening attachment member 8 (more specifically, the main body member 41), 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 main body member 41, the inner bag 4 can be pulled out of the container body 2.

[0038] 1-2. Manufacturing Method of Double Container 1 The container body 2 can be manufactured by biaxially stretching blow molding the preform 15 shown in Fig. 7. The double container 1 can also be manufactured by attaching the mouth attachment member 8 to the container body 2.

[0039] <Configuration of Inner Preform 14 , Outer Preform 13 , and Preform 15 > As shown in FIG. 6 , the preform 15 includes the inner preform 14 that will become the inner bag 4 and the outer preform 13 that will become the outer shell 3 .

[0040] As shown in Fig. 6, the inner preform 14 is cylindrical with a bottom and includes a mouth 14a, a body 14b, and a bottom 14c. The bottom 14c is provided so as to close the lower end of the body 14b. The outer preform 13 is cylindrical with a bottom and includes a mouth 13a, a body 13b, and a bottom 13c. The bottom 13c is provided so as to close the lower end of the body 13b.

[0041] As shown in Figure 7, the preform 15 can be formed by covering the inner preform 14 with the outer preform 13. The mouth portions 13a, 14a become the mouth portion 15a of the preform 15, the body portions 13b, 14b become the body portion 15b of the preform 15, and the bottom portions 13c, 14c become the bottom portion 15c of the preform 15. During biaxial stretch blow molding, the portion below the flange 13d (the body portion 15b and the bottom portion 15c) is mainly stretched. 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 does not contradict the intent thereof.

[0042] <Materials and manufacturing method of inner preform 14, outer preform 13, and preform 15> The inner preform 14 and outer preform 13 can be formed by direct blow molding or injection molding using a thermoplastic resin such as polyester (e.g., PET) or polyolefin (e.g., polypropylene, polyethylene).

[0043] The outer preform 13 is preferably formed by injection molding, while the inner preform 14 is preferably formed by direct blow molding using a molten cylindrical parison. Direct blow molding has the advantage over injection molding that it is easier to make thinner and multi-layered preforms.

[0044] 2. Second Embodiment A second embodiment of the present invention will be described using Figures 8 and 9. This embodiment is similar to the first embodiment, and the content described in the first embodiment can also be applied to this embodiment as long as it does not contradict the spirit of the first embodiment. This embodiment differs mainly from the first embodiment in the shapes of the mouth-mounted member 8 and the outer shell 3. The following description will focus on these differences.

[0045] In this embodiment, the inner peripheral surface 41d2 of the main body member seal cylinder 41d and the outer peripheral surface 3g3 of the outer shell seal cylinder 3g are in close contact with each other at a contact surface 51. The contact surface 51 is preferably inclined with respect to the axial direction. This inclination angle is, for example, 0.5 to 10 degrees (5 degrees in this embodiment), and preferably 3 to 8 degrees. Specific examples of this inclination angle include 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, and 10.0 degrees, and may be in a range between any two of the values ​​exemplified here.

[0046] The outer peripheral surface 3g3 is inclined so that its diameter decreases toward the tip 3g2 of the outer shell seal tube 3g. This makes it easier to bring the inner peripheral surface 41d2 into close contact with the outer peripheral surface 3g3. When the inner peripheral surface 41d2 is brought into close contact with the outer peripheral surface 3g3, a close contact surface 51 is formed. When the inner peripheral surface 41d2 is not pressed against the outer peripheral surface 3g3, the inner peripheral surface 41d2 and the outer peripheral surface 3g3 may be parallel or non-parallel.

[0047] In this embodiment, the main body member 41 does not have an outer tube 41e. The main body member sealing tube 41d is disposed at the outermost portion of the main body member 41. The tip 41d3 of the main body member sealing tube 41d is disposed adjacent to the first flange portion 3f1. The outer peripheral surface of the main body member sealing tube 41d is flush with the outer peripheral surfaces of the first and second flange portions 3f1, 3f2. This configuration improves the aesthetic appearance of the double container 1.

[0048] 3. Third Embodiment A third embodiment of the present invention will be described using Figures 10 to 12. This embodiment is similar to the above-described embodiment, and the contents described in the above-described embodiment can also be applied to this embodiment as long as they do not contradict the spirit of the embodiment. This embodiment differs mainly from the first embodiment in the shapes of the mouth attachment member 8, inner bag 4, and outer shell 3. The following description will focus on these differences.

[0049] 10, the spout-mounted member 8 includes a main body member 41 and a discharge member 43. The discharge member 43 has a discharge port 43a that communicates with the interior of the inner bag 4.

[0050] As shown in FIGS. 11 and 12 , the main body member 41 has an insertion hole 41h through which the protruding portion 4c is inserted. The protruding portion 4c is inserted through the insertion hole 41h. The protruding portion 4c of the inner bag 4 has an engaging portion 4c6 and an engaging portion 4c3, in that order from the opening end 5c side. The discharge member 43 is attached to a distal end portion 4c5 of the protruding portion 4c that protrudes from the main body member 41 through the insertion hole 41h. More specifically, the distal end portion 4c5 has an engaging portion 4c6, and the discharge member 43 is attached to the distal end portion 4c5 by engaging with the engaging portion 4c6. In this embodiment, the engaging portion 4c6 is a male threaded portion 4c12 provided on the outer surface of the distal end portion 4c5, and this male threaded portion is threadedly engaged with a female threaded portion 43b provided on the inner circumferential surface of the discharge member 43. The discharge member 43 may be attached to the distal end portion 4c5 in a capping manner.

[0051] The main body member 41 includes an inner tube 41b and a main body member seal tube 41d. The inner tube 41b has a smaller outer diameter than the main body member seal tube 41d. The main body member seal tube 41d is provided with an engaging protrusion 41d4 that axially engages with the protrusion 4c. The engaging protrusion 41d4 axially engages with the protrusion 4c (more specifically, with the engaging portion 4c3), thereby axially engaging the main body member 41 with the protrusion 4c. It is also preferable that the main body member seal tube 41d circumferentially engages with the protrusion 4c. In this case, the protrusion 4c can be rotated in conjunction with the rotation of the main body member 41. The inner tube 41b and the main body member seal tube 41d are connected to each other by a top surface 41g. An insertion hole 41h is provided in the top surface 41g.

[0052] The inner peripheral surface 41d2 of the main body member seal tube 41d and the outer peripheral surface 3g4 of the outer shell 3 at a position adjacent to the open end 3a thereof are in close contact with each other at a contact surface 51. The contact surface 51 is preferably inclined with respect to the axial direction. In other words, the contact surface 51 is preferably inclined so that its diameter decreases upward. This inclination angle is, for example, 0.5 to 15 degrees (7.5 degrees in this embodiment), and preferably 3 to 10 degrees. Specific examples of this inclination angle include 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 11, 12, 13, 14, and 15 degrees, and may be in a range between any two of the values ​​exemplified here.

[0053] Additionally, the inner circumferential surface 41b1 of the inner cylinder 41b is in close contact with the outer circumferential surface 4c7 of the protrusion 4c. A contact surface 52 between the inner circumferential surface 41b1 of the inner cylinder 41b and the outer circumferential surface 4c7 of the protrusion 4c is preferably inclined with respect to the axial direction. In other words, the contact surface 52 is preferably inclined so that its diameter decreases upward. This inclination angle is, for example, 0.5 to 15 degrees (6.7 degrees in this embodiment), and preferably 3 to 10 degrees. Specifically, this inclination angle may be, for example, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 11, 12, 13, 14, or 15 degrees, or may be in a range between any two of the values ​​exemplified here.

[0054] Also with the configuration of this embodiment, the main body member 41 is in close contact with both the outer shell 3 and the inner bag 4, so that an airtight space can be formed between the outer shell 3 and the inner bag 4.

[0055] 12, a tip 4c8 of the protrusion 4c (in other words, the open end 5c) has a reduced-diameter portion 4c9 formed by bending a portion adjacent to the tip 4c8 (in other words, the outer peripheral surface at a position adjacent to the open end 5c) radially inward. If the inner diameter of the reduced-diameter portion 4c9 is Di and the outer diameter is Do, then Di / Do is, for example, 0.60 to 0.95 (0.80 in this embodiment), and preferably 0.70 to 0.90. Specific examples of this value include 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, and 0.95, and may be within a range between any two of the values ​​exemplified here.

[0056] If the thickness of the inner circumferential surface 4c13 of the reduced diameter portion 4c9 is T, the value of {(Do-Di) / T} is, for example, 2.5 or more (5.0 in this embodiment), and preferably 3.5 or more. This value is, for example, 2.5 to 15, and preferably 3.5 to 10, and specifically, for example, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 11, 12, 13, 14, or 15, or may be in a range between any two of the values ​​exemplified here. The thickness T is, for example, 0.40 to 1.20 mm, and preferably 0.50 to 1.00 mm. Specific examples of this thickness include 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00, 1.05, 1.10, 1.15, and 1.20 mm, and may be in a range between any two of the values ​​exemplified here.

[0057] A seal member 44 is welded to the upper surface 4c10 of the reduced diameter portion 4c9. In one example, the seal member 44 is configured by laminating a sealant layer and a gas barrier layer, with the sealant layer welded to the upper surface 4c10. In one example, the gas barrier layer is an aluminum layer. By welding the seal member 44 thus configured to the upper surface 4c10 and closing the opening 4c11 at the tip 4c8, deterioration of the contents within the inner bag 4 is suppressed. At the start of use, the discharge member 43 can be temporarily removed, the seal member 44 can be peeled off, and then the discharge member 43 can be reattached to the tip portion 4c5.

[0058] The upper surface 4c10 of the reduced diameter portion 4c9 is preferably inclined so as to rise toward the radial center of the protruding portion 4c (i.e., toward the outside of the protruding portion 4c in the axial direction). The inclination angle of the upper surface 4c10 with respect to the horizontal plane (i.e., a plane perpendicular to the axial direction) is, for example, 1 to 25 degrees (12 degrees in this embodiment), and preferably 5 to 20 degrees. When this inclination angle is within the above range, welding defects of the seal member 44 are unlikely to occur. Specifically, this inclination angle may be, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 degrees, or may be in a range between any two of the values ​​exemplified here.

[0059] The discharge member 43 includes a discharge member body 45 and an overcap 46. The discharge member body 45 includes a nozzle 45a and an engaging tube 45b. The nozzle 45a and the engaging tube 45b are connected to each other by a top surface 45c. The nozzle 45a is provided with a discharge port 45d that communicates with the interior of the inner bag 4, allowing the contents of the inner bag 4 to be discharged through the nozzle 45a and the discharge port 45d. The nozzle 45a is provided with a discharge valve 42. The discharge port 45d can be closed using the overcap 46, and when in use, the overcap 46 can be removed to open the discharge port 45d and discharge the contents.

[0060] 4. Fourth Embodiment A fourth embodiment of the present invention will be described using Figures 13 to 15. This embodiment is similar to the above-described embodiment, and the contents described in the above-described embodiment can also be applied to this embodiment as long as they do not contradict the spirit of the embodiment. This embodiment differs mainly from the third embodiment in the shapes of the main body member 41 and the outer shell 3. The following description will focus on these differences.

[0061] In this embodiment, the main body member 41 includes an inner tube 41b, an engagement tube 41c, and a main body member sealing tube 41d. The outer diameters of these cylindrical portions increase in this order. These cylindrical portions are connected to each other by a top surface 41g. The engagement tube 41c and the main body member sealing tube 41d are connected to each other at a position farther from the tip 41c2 of the engagement tube 41c than the engagement protrusion 41c1.

[0062] In this embodiment, the inner circumferential surface 41d2 of the main body member seal cylinder 41d and the outer circumferential surface 3g3 of the outer shell seal cylinder 3g are in close contact with each other at a contact surface 51. The contact surface 51 is preferably inclined with respect to the axial direction. In other words, the contact surface 51 is preferably inclined so that its diameter decreases upward. This inclination angle is, for example, 0.5 to 15 degrees (5.8 degrees in this embodiment), and preferably 3 to 10 degrees. Specific examples of this inclination angle include 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 11, 12, 13, 14, and 15 degrees, and may be in a range between any two of the values ​​exemplified here.

[0063] Also with the configuration of this embodiment, the main body member 41 is in close contact with both the outer shell 3 and the inner bag 4, so that an airtight space can be formed between the outer shell 3 and the inner bag 4.

[0064] 5. Fifth Embodiment A fifth embodiment of the present invention will be described using Figures 16 and 17. This embodiment is similar to the above-described embodiment, and the contents described in the above-described embodiment can also be applied to this embodiment as long as they do not contradict the spirit of the embodiment. This embodiment differs mainly from the first embodiment in the shapes of the mouth attachment member 8, inner bag 4, and outer shell 3. The following description will focus on these differences.

[0065] In this embodiment, the main body member seal tube 41d is provided with an engaging protrusion 41d4 that axially engages with the protrusion 4c. The engaging protrusion 41d4 axially engages with the protrusion 4c (more specifically, with the engaging portion 4c3), thereby axially engaging the main body member 41 with the protrusion 4c.

[0066] A gap 2a is provided between the outer shell 3 and the inner bag 4 at the open end 3a of the outer shell 3. The tip 41i of the main body member sealing tube 41d is inserted into the gap 2a, and the outer peripheral surface 41i1 of the tip 41i is in close contact with the inner peripheral surface 3h of the outer shell 3. In this manner, in this embodiment, the contact surface 51 between the main body member 41 and the outer shell 3 is the surface where the outer peripheral surface 41i1 of the main body member sealing tube 41d and the inner peripheral surface 3h of the outer shell 3 are in close contact. Also, as in the first embodiment, the outer peripheral surface of the inner tube 41b of the main body member 41 is in close contact with the inner peripheral surface of the reduced diameter portion 4c2 of the inner bag 4. With this configuration, the main body member 41 is in close contact with both the outer shell 3 and the inner bag 4, thereby forming an airtight space between the outer shell 3 and the inner bag 4. In order to stably bring the outer peripheral surface 41i1 of the tip portion 41i into close contact with the outer shell 3, it is preferable that the inner peripheral surface 41i2 of the tip portion 41i be in close contact with the outer peripheral surface 4c14 of the inner bag 4.

[0067] The tip portion 41i including the contact surface 51 is preferably a soft portion made of elastomer to enhance adhesion to the shell 3. The portions other than the tip portion 41i are preferably made of a resin (e.g., a polyolefin such as polyethylene or polypropylene) that is more rigid than the tip portion 41i. The tip portion 41i and the other portions are preferably integrally molded by two-color molding or the like.

[0068] In this embodiment, the engaging protrusion 41d4 of the main body member sealing tube 41d is engaged with the engaging portion 4c3, but as in the first embodiment, an engaging tube 41c having an engaging protrusion 41c1 may be provided, and the engaging protrusion 41c1 may be engaged with the engaging portion 4c3.

[0069] A flange portion 3f is provided at the open end 3a of the outer shell 3. The tip 41e1 of the outer cylinder 41e is disposed close to the flange portion 3f. The outer peripheral surface of the outer cylinder 41e is flush with the outer peripheral surface of the flange portion 3f. This configuration improves the aesthetic appearance of the double container 1. The discharge valve 42 is fixed to the underside of the top surface 41g. This makes it easier to insert the inner cylinder 46a of the overcap 46 into the nozzle 41a.

[0070] 6. Sixth Embodiment A sixth embodiment of the present invention will be described using Figures 18 and 19. This embodiment is similar to the above-described embodiments, and the details described in the above-described embodiments can also be applied to this embodiment as long as they do not contradict the spirit of the embodiments. This embodiment differs mainly from the fifth embodiment in the shapes of the mouth attachment member 8, inner bag 4, and outer shell 3. The following description will focus on these differences.

[0071] In this embodiment, the main body member seal tube 41d is provided with an engaging protrusion 41d4, and the inner circumferential surface 41d2 at a position closer to the tip 41d3 than the engaging protrusion 41d4 is in tight contact with the outer circumferential surface 3g4 at a position adjacent to the open end 3a of the outer shell 3. Therefore, the contact surface 51 is provided in a portion adjacent to the open end 3a of the outer shell 3.

[0072] The main body member sealing tube 41d engages with the outer shell 3 at a position farther from the open end 3a of the outer shell 3 than the contact surface 51. In this embodiment, the outer shell 3 and the main body member sealing tube 41d are engaged by threading the male thread portion 3i on the outer shell 3 with the female thread portion 41j on the main body member sealing tube 41d. However, the outer shell 3 and the main body member sealing tube 41d may be snap-engaged (snap-fit ​​engagement or stopper-type engagement). When the outer shell 3 and the main body member sealing tube 41d are snap-engaged, it is preferable to provide the main body member 41 with a structure that allows the engagement between the outer shell 3 and the main body member sealing tube 41d to be released by tearing a portion of the main body member 41. Furthermore, the outer peripheral surface of the inner tube 41b of the main body member 41 is in close contact with the inner peripheral surface of the inner bag 4. With this structure, the main body member 41 is in close contact with both the outer shell 3 and the inner bag 4, thereby forming an airtight space between the outer shell 3 and the inner bag 4. As shown in the third and fourth embodiments, the main body member 41 may be configured to be in close contact with the outer peripheral surface of the inner bag 4. The same applies to the other embodiments.

[0073] The tip 4c8 of the protrusion 4c is provided with an expanded diameter portion 4c15 formed by bending a portion adjacent to the tip 4c8 radially outward. The engaging portion 4c3 is formed by the expanded diameter portion 4c15. The engaging protrusion 41d4 is disposed between the engaging portion 4c3 and the open end 3a.

[0074] The tip 41d3 of the cylindrical body member seal 41d is located close to the flange 3f, and the outer circumferential surface of the cylindrical body member seal 41d is flush with the outer circumferential surface of the flange 3f. This configuration improves the aesthetic appearance of the double container 1.

[0075] 20 and 21 , the outer shell 3 has a plurality of annular protrusions 47 arranged along the axial direction at the contact surface 51. Each of the plurality of annular protrusions 47 contacts the main body member seal tube 41d, thereby enhancing contact. The plurality of annular protrusions 47 may be provided on the main body member seal tube 41d, or may be provided on both the outer shell 3 and the main body member seal tube 41d.

[0076] In Modification 2 shown in Figures 22 and 23, the contact surface 51 is inclined with respect to the axial direction. The outer peripheral surface 3g4 is inclined so that its diameter decreases toward the open end 3a. This tends to improve the contact at the contact surface 51. This inclination angle is, for example, 0.5 to 10 degrees (4 degrees in this embodiment), and preferably 1 to 8 degrees. Specific examples of this inclination angle are 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6, 7, 8, 9, and 10 degrees, and may be in a range between any two of the values ​​exemplified here.

[0077] 7. Seventh Embodiment A seventh embodiment of the present invention will be described using Figures 24 and 25. This embodiment is similar to the above-described embodiments, and the content described in the above-described embodiments can also be applied to this embodiment as long as it does not contradict the spirit of the above-described embodiments. This embodiment differs mainly from the sixth embodiment in the shapes of the mouth attachment member 8, inner bag 4, and outer shell 3. The following description will focus on these differences.

[0078] In this embodiment, the inner circumferential surface 41d2 at a position adjacent to the tip 41d3 of the main body member sealing cylinder 41d is in close contact with the outer circumferential surface 3g4 at a position adjacent to the open end 3a of the outer shell 3. Therefore, at the contact surface 51, the portion adjacent to the tip 41d3 of the main body member sealing cylinder 41d is in close contact with the portion adjacent to the open end 3a of the outer shell 3. The configurations of Modifications 1 and 2 of the sixth embodiment can also be applied to this embodiment.

[0079] The inner bag 4 is provided with a contact protrusion 4v that protrudes radially outward, and the contact protrusion 4v abuts against the opening end 3a, thereby stably supporting the inner bag 4 on the outer shell 3.

[0080] The main body member sealing tube 41d is provided with a female thread portion 41j and an engaging protrusion 41d4, in that order from the tip 41d3 side. The protrusion 4c of the inner bag 4 is provided with a male thread portion 4c12 and an engaging portion 4c3, in that order from the base side of the protrusion 4c. When the female thread portion 41j and the male thread portion 4c12 are screwed together, the engaging protrusion 41d4 snaps into the engaging portion 4c3, and the main body member 41 is stably supported by the protrusion 4c.

[0081] 8. Eighth Embodiment An eighth embodiment of the present invention will be described using Figures 26 and 27. This embodiment is similar to the above-described embodiments, and the content described in the above-described embodiments can also be applied to this embodiment as long as it does not contradict the spirit of the above-described embodiments. This embodiment differs mainly from the sixth embodiment in the shapes of the mouth attachment member 8, inner bag 4, and outer shell 3. The following description will focus on these differences.

[0082] In this embodiment, the tip 41d3 of the main body member sealing tube 41d is in close contact with the upper surface 3f3 of the flange portion 3f of the outer shell 3. Therefore, the contact surface 51 is provided at the tip 41d3 of the main body member sealing tube 41d. To improve the contact at the contact surface 51, the tip portion 41k including the contact surface 51 is preferably a soft portion made of elastomer. Furthermore, the portions other than the tip portion 41k are preferably made of a resin (e.g., a polyolefin such as polyethylene or polypropylene) that is more rigid than the tip portion 41k. The tip portion 41k and the other portions are preferably integrally molded by two-color molding or the like.

[0083] The main body member 41 preferably engages with the outer shell 3. This makes it easy to press the tip 41d3 axially against the upper surface 3f3, thereby increasing adhesion. Furthermore, it is even more preferable that the main body member 41 and the outer shell 3 are screwed together. In this case, it is easy to increase the force that presses the tip 41d3 axially against the upper surface 3f3. In this embodiment, the male thread portion 3i provided on the outer shell 3 and the female thread portion 41j provided on the main body member seal tube 41d are screwed together. Furthermore, this screwing allows the engaging protrusion 41d4 to snap-engage with the engaging portion 4c3.

[0084] 9. Ninth Embodiment A ninth embodiment of the present invention will be described using Figures 28 to 30. This embodiment is similar to the above-described embodiments, and the details described in the above-described embodiments can also be applied to this embodiment as long as they do not contradict the spirit of the embodiments. This embodiment differs mainly from the sixth embodiment in the shapes of the mouth attachment member 8, inner bag 4, and outer shell 3. The following description will focus on these differences.

[0085] In the above embodiment, the main body member 41 and the outer shell 3 are in direct contact with each other at the contact surface 51. However, in the present embodiment, the main body member 41 and the outer shell 3 are in contact with each other at the contact surface 51 via another member. Specifically, in the present embodiment, the other member is a soft member 53 disposed between the open end 3a of the outer shell 3 and the main body member 41 (more specifically, the top surface 41g), and the main body member 41 and the outer shell 3 are in contact with each other via the soft member 53. The upper and lower surfaces of the soft member 53 each serve as the contact surface 51. The soft member 53 is made of an elastomer. Note that, in the above embodiment, the main body member 41 and the outer shell 3 may also be configured to be in contact with each other via another member.

[0086] The main body member seal tube 41d is provided with a support protrusion 41d5, and the soft member 53 is supported by the support protrusion 41d5 and attached to the main body member 41. This configuration improves the handleability of the soft member 53. The support protrusion 41d5 is preferably provided in an annular shape.

[0087] A protrusion 3a4 is provided at the open end 3a of the outer shell 3, and the protrusion 3a4 is pressed against the soft member 53 to improve the sealing performance between the soft member 53 and the open end 3a. The protrusion 3a4 is preferably tapered toward the tip and is preferably annular.

[0088] (Second Aspect) The second aspect of the present invention will be described below. The matters described in the first aspect are applicable to this aspect as long as they do not contradict the spirit of the first aspect, and the matters described in this aspect are applicable to the above aspect as long as they do not contradict the spirit of the first aspect. The following description will focus on the differences from the above aspect.

[0089] 1. First Embodiment A first embodiment of the present invention will be described with reference to FIGS.

[0090] 1-1. Configuration of Container 10 <Basic Configuration> As shown in Figures 31 and 32, the container 10 of the first embodiment of the present invention comprises a container body 2 and a spout attachment member 8. The container 10 is a bottle-shaped container capable of holding beverages, seasonings, etc. The container 10 may be a single-walled container or a double-walled container. The following description will be given taking as an example a case where the container 10 is a double-walled container 1.

[0091] The double container 1 of this embodiment has a structure similar to that of the third embodiment of the first aspect, except that the inner diameter of the tapered portion 4c9 is slightly different from that of the third embodiment of the first aspect. Therefore, the matters described in relation to the third embodiment of the first aspect can also be applied to this embodiment, as long as they do not contradict the intent thereof.

[0092] 35, the open end 5c of the protrusion 4c has a reduced diameter portion 4c9 formed by bending the outer peripheral surface adjacent to the open end 5c radially inward. If the inner diameter of the reduced diameter portion 4c9 is Di and the outer diameter is Do, then Di / Do is, for example, 0.50 to 0.95 (0.70 in this embodiment), and preferably 0.76 to 0.90. Specific examples of this value include 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, and 0.95, and may be in a range between any two of the values ​​exemplified here.

[0093] If the thickness of the inner circumferential surface 4c13 of the reduced diameter portion 4c9 is T, the value of {(Do-Di) / T} is, for example, 2.5 or more (7.2 in this embodiment), and preferably 4 or more. This value is, for example, 2.5 to 15, and preferably 4 to 10, and specifically, for example, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 11, 12, 13, 14, or 15, or may be in a range between any two of the values ​​exemplified here. The thickness T is, for example, 0.40 to 1.20 mm, and preferably 0.50 to 1.00 mm. Specific examples of this thickness include 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00, 1.05, 1.10, 1.15, and 1.20 mm, and may be in a range between any two of the values ​​exemplified here.

[0094] 1-2. Manufacturing Method of Container 10 The container body 2 can be manufactured by a method including a biaxially stretched blow molding process and a cutting process. The container 10 can also be manufactured by attaching the mouth attachment member 8 to the container body 2.

[0095] 1-2-1 Preform 15 The preform 15 includes an inner preform 14 that will become the inner bag 4 and an outer preform 13 that will become the outer shell 3.

[0096] As shown in Figure 36, the inner preform 14 is cylindrical with a bottom, and includes a mouth 14a, a body 14b, and a bottom 14c. The bottom 14c is provided so as to close the lower end of the body 14b. A protrusion 14d is provided on the mouth 14a. As shown in Figure 37, the protrusion 14d is a portion of the preform 15 that protrudes from the open end 13f of the outer preform 13. The protrusion 14d does not deform during molding, and remains in its original shape to become the protrusion 4c.

[0097] As shown in Figures 36 and 37, the inner preform 14 has a cylindrical extension 14f extending from a portion 14e corresponding to the open end 5c of the container body 2. The extension 14f is provided on the protrusion 14d. The extension 14f has, in order from the open end 14g side of the inner preform 14, an expanded diameter portion 14h and a reduced diameter portion 14i. The reduced diameter portion 14i has an inner diameter smaller than that of the expanded diameter portion 14h. The expanded diameter portion 14h and the reduced diameter portion 14i are connected by an inclined portion 14j.

[0098] 36, the outer preform 13 is cylindrical with a bottom and includes a mouth 13a, a body 13b, and a bottom 13c. The bottom 13c is provided to close the lower end of the body 13b.

[0099] As shown in Figure 37, the preform 15 can be formed by covering the inner preform 14 with the outer preform 13. The mouth portions 13a, 14a become the mouth portion 15a of the preform 15, the body portions 13b, 14b become the body portion 15b of the preform 15, and the bottom portions 13c, 14c become the bottom portion 15c of the preform 15. During biaxial stretch blow molding, the portion closer to the bottom portion 15c than the flange 13d (the body portion 15b and the bottom portion 15c) is mainly stretched. 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 does not contradict the intent thereof.

[0100] The inner preform 14 and the outer preform 13 can be formed by direct blow molding or injection molding using a thermoplastic resin such as polyester (e.g., PET) or polyolefin (e.g., polypropylene, polyethylene). The outer preform 13 is preferably formed by injection molding. The inner preform 14 is preferably formed by direct blow molding using a molten cylindrical parison. Direct blow molding has the advantage that it is easier to make thinner and multi-layered parts than injection molding.

[0101] 37 to 39, the biaxially stretched blow molding process will be described. In the biaxially stretched blow molding process, the preform 15 is attached to the blow core 21 so that the insertion portion 21b of the blow core 21 is positioned within the preform 15, and the preform 15 is then biaxially stretched and blow molded.

[0102] In one example, the biaxial stretch blow molding process includes a mounting step, a heating step, and a stretching step. Each step will be described below.

[0103] <Attachment Process> In the attachment process, as shown in Figures 37 and 38, the preform 15 is attached to the blow core 21 so that the insertion portion 21b of the blow core 21 is positioned within the preform 15 (more specifically, the extension portion 14f). The blow core 21 includes a base portion 21a, an insertion portion 21b, and a through hole 21c. The insertion portion 21b is provided so as to protrude from the base portion 21a. The insertion portion 21b is tapered, making it easier to insert the insertion portion 21b into the extension portion 14f of the preform 15.

[0104] The insertion portion 21b has, in order from the distal end 21g side, a reduced diameter portion 21h, an inclined portion 21i, and an expanded diameter portion 21j. The reduced diameter portion 21h has a smaller outer diameter than the expanded diameter portion 21j. The expanded diameter portion 21j and the reduced diameter portion 21h are connected by the inclined portion 21i. The reduced diameter portion 21h, the inclined portion 21i, and the expanded diameter portion 21j have shapes corresponding to the reduced diameter portion 14i, the inclined portion 14j, and the expanded diameter portion 14h, respectively, and preferably have complementary shapes. As shown in FIG. 38 , when the insertion portion 21b is inserted into the extension portion 14f, it is preferable that at least one (preferably two or three) of the reduced diameter portion 21h, the inclined portion 21i, and the expanded diameter portion 21j abut or come into close proximity with the reduced diameter portion 14i, the inclined portion 14j, and the expanded diameter portion 14h, respectively. For example, the inclined portion 21i can be in contact with the inclined portion 14j, the reduced diameter portion 21h can be in contact with or close to the reduced diameter portion 14i, and the expanded diameter portion 21j can be in contact with or close to the expanded diameter portion 14h. By providing the extension portion 14f as in this embodiment, it is possible to make the inner circumferential surface of the inner preform 14 and the outer circumferential surface of the insertion portion 21b face each other over a wide area, and by making the inner circumferential surface of the extension portion 14f in contact with or close to the outer circumferential surface of the insertion portion 21b, leakage of air from the gap between the inner preform 14 and the blow core 21 during biaxial stretch blow molding is suppressed.

[0105] For example, in a comparative preform 15X in which the inner preform 14 does not have an extension 14f, as shown in Figure 41, the inner preform 14 and the blow core 21 come into contact or are close to each other only at the inner surface 14e1 of the portion 14e corresponding to the opening end 5c of the container body 2. However, since the area of ​​the inner surface 14e1 is very small, air leakage is likely to occur from the gap between the inner preform 14 and the blow core 21.

[0106] Furthermore, the preform 15 is preferably transported while being supported by the blow core 21, and by providing the extension 14f, the preform 15 can be stably supported by the blow core 21. On the other hand, as shown in Figure 41, if the inner preform 14 does not have the extension 14f, the preform 15 is supported by the blow core 21 at the inner peripheral surface 14e1, which has a small area, and the supporting state is likely to become unstable.

[0107] <Heating Process> The heating process can be performed using a heating device 35 shown in FIG. 38. In the heating process, the preform 15 is heated and softened to a softened state. In one example, the heating process can be performed by placing the preform 15 in proximity to a heater 32 while the preform 15 is attached to a blow core 21, as shown in FIG. 38. The heating process is performed by heating the body portion 15b and bottom portion 15c while the flange 13d provided on the preform 15 is covered with a heat shield 33. This softens the body portion 15b and bottom portion 15c. On the other hand, the flange 13d and the mouth portion 15a covered with the heat shield 33 receive little or no heat from the heater 32 and are not softened. In one example, the preform 15 can be heated while being rotated. In one example, the heater 32 is composed of multiple rod-shaped heaters arranged along the side of the preform 15, but other configurations are also possible.

[0108] <Stretching Step> The stretching step can be performed using a blow molding device 36 shown in Fig. 39. In the stretching step, the softened preform 15 is stretched. In one example, the stretching step includes a first stretching step and a second stretching step.

[0109] First Stretching Step In the first stretching step, the preform 15 is stretched along a first axial direction (i.e., the vertical direction). The first axis is, for example, a direction parallel to the central axis C of the mouth portion 5, i.e., the vertical direction in FIG. 39 . In one example, as shown in FIG. 39 , this step can be performed by setting the heated preform 15 in a molding die 23, supporting the bottom 15c of the preform 15 with a bottom support die 22, and then pressing a stretch rod 25 inserted through a through hole 21c in the blow core 21 against the inner bottom surface of the inner preform 14 to stretch it. At this time, it is preferable to retract the bottom support die 22 in synchronization with the extension of the stretch rod 25. This allows the preform 15 to be stably stretched.

[0110] The preform 15 can be transferred from the heating device 35 to the blow molding device 36 while supported by the blow core 21. The molding die 23 is composed of a split mold that can be opened and closed, and includes a cavity surface 23a corresponding to the outer surface shape of the container body 2, and a flange accommodating portion 23b that can accommodate the flange 13d. The preform 15 is set in the molding die 23 so that the flange 13d is disposed within the flange accommodating portion 23b. The first stretching step can be performed in a state where the flange 13d is pressed against an opposing surface 23c that faces the flange 13d in the first axial direction.

[0111] Second Stretching Step In the second stretching step, after the first stretching step, air is blown into the inner preform 14 to stretch (i.e., expand) the preform 15 in the second axial direction (i.e., the lateral direction) and shape it into the shape of the cavity surface 23a. Air can be blown in through the through holes 21c provided in the blow core 21. In this embodiment, the provision of the extensions 14f prevents air from leaking from the gap between the inner preform 14 and the blow core 21, thereby preventing molding defects.

[0112] By the above steps, a molded body 2b having a structure in which the extension 14f is connected to the container body 2 is obtained as shown in FIG.

[0113] In the cutting step, after the biaxially stretched blow molding step, the extension 14f is cut off along the dotted line 48. This results in the container body 2 having the structure shown in Fig. 35. After the cutting step, the opening end 5c is provided with a reduced diameter portion 4c9 formed by bending the outer circumferential surface at a position adjacent to the opening end 5c radially inward.

[0114] 1-2-4. Content Filling Process and Sealing Process After the cutting process, the content filling process and sealing process may be performed in this order. In the content filling process, the container body 2 is filled with the content. Examples of the content include mayonnaise and sauce. In the sealing process, a sealing member 44 is welded to the upper surface 4c10 of the reduced diameter portion 4c9 to close the opening 4c11 at the open end 5c. This prevents the content from deteriorating.

[0115] 2. Other Embodiments In the above embodiment, the preform 15 is a two-body structure of the inner preform 14 and the outer preform 13, but it may be an integrated structure. In this case, an extension 14f is provided on the preform 15. In this case, the description of the inner preform 14 in the above embodiment can be read as a description of the preform 15, as long as it does not contradict the spirit of the description.

[0116] 1: Double container, 2: Container body, 2a: Gap, 2b: Molded body, 3: Outer shell, 3a: Opening end, 3a1: Base surface, 3a3: Inner bag support surface, 3a4: Projection, 3f: Flange section, 3f1: First flange section, 3f2: Second flange section, 3f3: Top surface, 3g: Outer shell seal tube, 3g1: Inner peripheral surface, 3 g2: tip, 3g3: outer circumferential surface, 3g4: outer circumferential surface, 3h: inner circumferential surface, 3i: male threaded part, 3l: cam rail, 4: inner bag, 4a: first cylinder, 4b: first 2 cylinders, 4b4: Bottom surface, 4c: Protruding part, 4c1: Expanded diameter part, 4c10: Upper surface, 4c11: Opening part, 4c12: Male thread part, 4c13: Inner peripheral surface, 4c 14: Outer peripheral surface, 4c15: Expanded diameter part, 4c2: Reduced diameter part, 4c3: Engagement part, 4c4: Part, 4c5: Tip part, 4c6: Engagement part, 4c7: Outer periphery Surface, 4c8: Tip, 4c9: Reduced diameter portion, 4d: Inner bag main body, 4g: Convex strip, 4v: Contact convex portion, 5: Mouth, 5c: Open end, 6: Body, 6b: Shoulder, 6c: trunk body, 7: bottom, 8: mouth attachment member, 8a: cap, 10: container, 13: outer preform, 13a: mouth, 13b: trunk, 13c: bottom, 13d: flange, 13f: open end, 14: inner preform, 14a: mouth, 14b: trunk, 14c: bottom, 14d: protrusion, 14e: part, 14e1: inner peripheral surface, 14f: extension portion, 14g: opening end, 14h: enlarged diameter portion, 14i: reduced diameter portion, 14j: inclined portion, 15: preform, 15X: preform, 15a: mouth portion, 15b: body portion, 15c: bottom portion, 21: blow core, 21a: base portion, 21b: insertion portion, 21c: through hole, 21g: tip portion, 21h: reduced diameter portion, 21i: inclined portion, 21j: enlarged diameter portion, 22: bottom support mold, 23: molding mold, 23a: cavity surface, 23b: flange accommodating portion, 23c: opposing surface, 25: stretch rod, 32: heater, 33: heat shield portion, 35: heating device, 36: blow molding device, 41: main body member, 41a: nozzle, 41b: inner cylinder, 41b1: inner peripheral surface, 41c: engaging cylinder, 41c1: engaging protrusion, 41c2: tip, 41d: main body member sealing cylinder, 41d1: outer peripheral surface, 41d2: inner peripheral surface, 41d3: tip, 41d4: engaging protrusion, 41d5: supporting protrusion, 41e: outer cylinder, 41e1: tip, 41f: discharge port, 41g: top surface, 41h: insertion hole, 41i: tip, 41i1: outer peripheral surface, 41i2: inner peripheral surface, 41j: female thread portion, 41k: tip, 42: discharge valve, 43: discharge member, 43a: discharge port, 43b: female thread portion, 44: seal member, 45: discharge member main body,45a: nozzle, 45b: engagement tube, 45c: top surface portion, 45d: discharge port, 46: overcap, 46a: inner tube, 47: annular convex portion, 48: dotted line, 51: contact surface, 52: contact surface, 53: soft member, C: central axis, T: thickness,

Claims

1. A double container comprising a container body and a mouth attachment member attached to the mouth of the container body, wherein the container body comprises an inner bag and an outer shell arranged to cover the inner bag, the inner bag having a protrusion protruding from the open end of the outer shell, and when the direction in which the central axis of the mouth of the container body extends is taken as the axial direction, the mouth attachment member comprises a main body member, which is engaged with the protrusion in the axial direction, and the main body member has a discharge port communicating with the interior of the inner bag or an insertion hole through which the protrusion is inserted, and the main body member and the outer shell are in close contact with each other at their contact surfaces either directly or via another member.

2. A double container according to claim 1, wherein the main body member comprises a main body member sealing tube, and the main body member sealing tube and the outer shell are in close contact with each other at the contact surface, either directly or via another member.

3. A double container according to claim 2, wherein the contact surface is inclined with respect to the axial direction.

4. A double container as described in claim 2, wherein the main body member has an engaging tube, the engaging tube has an engaging protrusion that engages with the protrusion in the axial direction, and the engaging tube and the main body member sealing tube are connected to each other at a position farther from the tip of the engaging tube than the engaging protrusion.

5. A double container according to claim 2, wherein the body member sealing tube is not engaged with the outer shell by projections and recesses.

6. A double container according to claim 2, wherein the outer shell comprises an outer shell sealing tube, and the sealing surface is disposed on the outer shell sealing tube.

7. A double container according to claim 6, wherein the contact surface is a surface where the outer peripheral surface of the main body member sealing tube and the inner peripheral surface of the outer shell sealing tube are in close contact with each other.

8. A double container according to claim 2, wherein the main body member has an inner tube having an outer diameter smaller than that of the main body member sealing tube, and the inner peripheral surface of the inner tube is in close contact with the outer peripheral surface of the protrusion.

9. A double container according to claim 8, wherein the contact surface between the inner peripheral surface of the inner cylinder and the outer peripheral surface of the protrusion is inclined with respect to the axial direction.

10. A double container as described in claim 2, wherein the main body member has an insertion hole through which the protrusion is inserted, the mouth attachment member has a discharge member having a discharge port that communicates with the inside of the inner bag, and the discharge member is attached to the tip of the protrusion that protrudes from the main body member through the insertion hole.

11. A double container according to claim 2, wherein the contact surface is a surface where the outer peripheral surface of the main body member sealing tube and the inner peripheral surface of the outer shell are in close contact with each other.

12. A double container according to claim 2, wherein the sealing surface is provided at the tip of the main body member sealing tube.

13. A double container according to claim 11, wherein the main body member sealing tube has a soft part made of elastomer integrally molded therewith so as to include the contact surface.

14. A double container according to claim 1, wherein the other member is a soft member made of elastomer, and the soft member is disposed between the open end of the outer shell and the main body member.

15. The double container of claim 12, wherein the body member and the outer shell are threadedly engaged.

16. A double container according to claim 2, wherein the sealing surface is provided at a location adjacent to the open end of the outer shell.

17. A double container according to claim 16, wherein the main body member sealing tube engages with the outer shell at a position farther from the open end of the outer shell than the contact surface.

18. A double container according to claim 16, wherein the sealing surface is in tight contact with a portion adjacent to the tip of the main body member sealing tube and a portion adjacent to the open end of the outer shell.

19. A double container according to claim 16, wherein at least one of the outer shell and the main body member sealing tube is provided with a plurality of annular protrusions aligned along the axial direction at the contact surface.

20. A method for manufacturing a double container according to any one of claims 1 to 19, wherein the container body of the double container is manufactured by biaxially stretched blow molding.

21. A method for manufacturing a container, comprising a biaxially stretched blow molding step and a cutting step, wherein in the biaxially stretched blow molding step, the preform is biaxially stretched blow molded while being attached to a blow core so that an insert portion of the blow core is positioned within the preform, the preform has a cylindrical extension portion extending from a portion corresponding to an open end of a container body of the container, the insert portion is inserted into the extension portion, and in the cutting step, the extension portion is cut off after the biaxially stretched blow molding step.

22. A method according to claim 21, wherein the opening end after the cutting step is provided with a reduced diameter portion formed by bending the outer circumferential surface at a position adjacent to the opening end radially inward, and the method comprises a contents filling step and a sealing step in this order after the cutting step, wherein the contents filling step fills the container body with contents, and the sealing step welds a sealing member to the upper surface of the reduced diameter portion to close the opening at the opening end.

23. The method of claim 21, wherein the inner circumferential surface of the extension and the outer circumferential surface of the insert are brought into contact or proximity.

24. A method according to any one of claims 21 to 23, wherein the preform is constructed by covering an outer preform with an inner preform, the inner preform has a protruding portion that protrudes from an open end of the outer preform, and the extension portion is provided on the protruding portion.

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