Double container and method for manufacturing the same

Abstract

To provide a double container capable of regulating the flow of air through an outside air introduction hole without enhancing the dimensional accuracy of the outside air introduction hole.SOLUTION: According to the present invention, there is provided a double-walled container including a container body, wherein the container body is a biaxially stretched blow-molded body, the container body includes an inner bag and an outer shell disposed to cover the inner bag, the container body is provided with a fresh air inlet penetrating the outer shell and an air flow regulating member for regulating an air flow through the fresh air inlet, and the air flow regulating member includes at least one member welded or bonded to the outer shell. Since the double-walled container of the present invention is excellent in recyclability, it can be suitably used for producing a recycled material.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a double container and a method for manufacturing the same. [Background technology]

[0002] Patent Document 1 discloses a method for producing a double-layered container by biaxially stretching blow molding. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] WO2022 / 215598 Summary of the Invention [Problem to be solved by the invention]

[0004] In the double container of Patent Document 1, an outside air inlet hole is provided in the container body, and a check valve is engaged and attached to this outside air inlet hole, so that the compressive force applied to the outer shell is transmitted to the inner bag and the outer shell returns to its original shape when the compressive force is removed.

[0005] In order to fit the check valve into the air inlet hole, the dimensional accuracy of the air inlet hole must be extremely high, but it is not easy to increase the dimensional accuracy of the air inlet hole.

[0006] The present invention has been made in consideration of the above circumstances, and provides a double container that can regulate the flow of air through an outside air introduction hole without increasing the dimensional accuracy of the outside air introduction hole. [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 being a biaxially stretched blow-molded product, the container body comprising an inner bag and an outer shell arranged to cover the inner bag, the container body being provided with an outside air inlet hole penetrating the outer shell and an air flow regulating member for regulating the flow of air through the outside air inlet hole, at least one of the components constituting the air flow regulating member being welded or adhered to the outer shell. [2] A double container as described in [1], wherein the air flow regulating member comprises a valve body and a moving body, the moving body being configured to be able to move within the space within the valve body, the valve body comprising a cylindrical portion having the space and a flange portion protruding radially from the cylindrical portion, and the flange portion being welded or bonded to the outer shell. [3] The double container according to [2], wherein the cylindrical portion is inserted into the outside air inlet hole. [4] A double container as described in [1], wherein the air flow regulating member comprises a valve body and a moving body, the moving body being configured to be able to move within the space within the valve body, the valve body being configured by combining a first member and a second member, the first member having an opening through which the moving body can pass without deforming the first member, the second member having an air hole through which the moving body cannot pass, and the second member being welded or adhered to the first member so that the air hole is in communication with the opening, and the first member or the second member being configured by the outer shell. [5] A method for manufacturing a double-layered container, comprising a biaxially stretched blow molding step and an arrangement step, wherein in the biaxially stretched blow molding step, a preform is biaxially stretched blow molded, the preform is configured by placing an outer preform on an inner preform, the outer preform has an outside air inlet hole at the bottom that penetrates the outer preform, the biaxially stretched blow molding is performed with the bottom supported by a bottom support mold, and in the arrangement step, after the biaxially stretched blow molding, an air flow regulating member is arranged to regulate the flow of air through the outside air inlet hole. [6] A method according to [5], wherein the container body formed by the method including the biaxially stretched blow molding step comprises an inner bag and an outer shell arranged to cover the inner bag, and the air flow regulating member is arranged by welding or adhering at least one of the members constituting the air flow regulating member to the outer shell. [7] The method according to [5] or [6], wherein the outer preform has an annular convex portion surrounding the external air inlet hole, and the bottom support mold is configured to suppress extension of the annular convex portion. [8] A method according to any one of [5] to [7], wherein the air flow regulating member is a check valve, the check valve comprises a valve body and a movable body that is movable within the space within the valve body, and the outside air introduction hole is configured to be able to accommodate at least a portion of the valve body. [Effects of the Invention]

[0008] In the double container of the present invention, the flow of air through the outside air inlet hole is restricted by joining an air flow restricting member to the area surrounding the outside air inlet hole. With this configuration, the dimensional accuracy of the outside air inlet hole does not affect the attachment of the air flow restricting member or air leakage, so the flow of air through the outside air inlet hole can be restricted without increasing the dimensional accuracy of the outside air inlet hole. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a front view of a double container 1 according to a first embodiment of the present invention. [Figure 2] FIG. 2 is an exploded view of FIG. 1. [Figure 3] 3A and 3B are cross-sectional views of regions A and B in FIG. 1, respectively. [Figure 4] 3B is a cross-sectional view showing a state in which the discharge member 43 is separated from the state of FIG. 3A. [Figure 5] 5 is a cross-sectional view showing a state in which the main body member 41 is separated from the state shown in FIG. 4. FIG. [Figure 6] Figure 6A is an enlarged view of area A in Figure 3B, and Figure 6B is an exploded view of Figure 6A. [Figure 7] FIG. 2 is a cross-sectional view showing a state in which the inner preform 14 and the outer preform 13 are separated. [Figure 8] 1 is a cross-sectional view of a preform 15 and a blow core 21. FIG. [Figure 9] 1 is a cross-sectional view showing a state in which a preform 15 is attached to a blow core 21 and brought close to a heater 32. FIG. [Figure 10] FIG. 2 is a cross-sectional view illustrating biaxial stretch blow molding of a preform 15. [Figure 11] Figure 11A is an enlarged view of area A in Figure 10. Figure 11B is an exploded view of Figure 11A. [Figure 12] FIG. 2 is a cross-sectional view of a molded body 2a obtained by biaxial stretch blow molding. [Figure 13] Fig. 13A is a view corresponding to Fig. 6A, showing the double container 1 of the second embodiment of the present invention, and Fig. 13B is an exploded view of Fig. 13A. [Figure 14] Fig. 14A is a view corresponding to Fig. 6A, showing the double container 1 according to the third embodiment of the present invention, and Fig. 14B is an exploded view of Fig. 14A. [Figure 15] Fig. 15A is a view corresponding to Fig. 6A, showing the double container 1 according to the fourth embodiment of the present invention, and Fig. 15B is an exploded view of Fig. 15A. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following describes embodiments of the present invention. The various features shown in the following embodiments can be combined with one another. Furthermore, each feature can be an independent invention. Furthermore, elements in the following embodiments that are not defined in the claims are optional 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."

[0011] The embodiments shown below include at least the inventions of the following aspects. The first aspect of the invention is A double container comprising a container body, the container body is a biaxially stretched blow molded article, The container body includes an inner bag and an outer shell disposed to cover the inner bag, the container body is provided with an outside air introduction hole penetrating the outer shell and an air flow regulation member that regulates the flow of air through the outside air introduction hole, The air flow restriction member is a double container in which at least one of the components constituting the air flow restriction member is welded or glued to the outer shell.

[0012] The second aspect of the invention is as follows: A method for manufacturing a double-layered container, comprising a biaxially stretched blow molding step and a placement step, In the biaxially stretched blow molding step, the preform is biaxially stretched blow molded, The preform is configured by covering an outer preform with an inner preform, the outer preform has an outside air introduction hole at its bottom that penetrates the outer preform, The biaxial stretch blow molding is performed in a state where the bottom is supported by a bottom support mold, In the arranging step, an air flow regulating member for regulating the flow of air through the outside air introduction hole is arranged after the biaxially stretch blow molding.

[0013] 1. First embodiment A first embodiment of the present invention will be described with reference to FIGS.

[0014] 1-1. Structure of double container 1 <Basic configuration> As shown in Figures 1 and 2, the double container 1 of the first embodiment of the present invention comprises a container body 2 and a spout attachment member 8. The double container 1 is a bottle-shaped container that can hold beverages, seasonings, etc. In the following description, terms related to directions, such as "upper" and "lower," refer to directions when the bottom 7 is in contact with the ground. In addition, in the following description, the "axial direction" refers to the direction in which the central axis C (shown in Figure 2) of the spout 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 rotational direction about the central axis C of the spout 5, for example, the direction in which the inner bag 4 is rotated at the spout 5 relative to the outer shell 3. Unless otherwise specified, "clockwise" and "counterclockwise" refer to directions as viewed from the top of the double container 1.

[0015] 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.

[0016] 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 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.

[0017] As shown in Figures 3 to 6, 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.

[0018] <Detailed structure of outer shell 3 and inner bag 4> 4 and 5, engaging portions 4c6 and 4c3 are provided in this order from the opening end 5c side on the protruding portion 4c of the inner bag 4. First and second flange portions 3f1 and 3f2 are provided in this order from the opening end 3a side on the outer shell 3.

[0019] As shown in Fig. 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.

[0020] A 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. The lower surface 4b4 is supported by the inner bag support surface 3a3, thereby preventing the inner bag 4 from falling off into the outer shell 3. The inner bag support surface 3a3 may be flush with the opening edge 3a, or may be provided at a lower position than the opening edge 3a. In this embodiment, the inner bag support surface 3a3 is provided at a lower position than the opening edge 3a. 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.

[0021] 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 provided on the outer peripheral surface of the inner bag 4 and a cam rail provided on the inner peripheral surface of the outer shell 3. 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 even easier to pull out.

[0022] <Mouth attachment part 8> The mouth-mounted member 8 is a member that is attached to the mouth 5 of the container body 2. As shown in Fig. 3A, the mouth-mounted member 8 includes a main body member 41 and a discharge member 43. The discharge member 43 has a discharge opening 43a that communicates with the interior of the inner bag 4.

[0023] 5, an insertion hole 41h through which the protrusion 4c is inserted is provided in the main body member 41. The protrusion 4c is inserted into the insertion hole 41h.

[0024] 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 at a top surface 41g. An insertion hole 41h is provided in the top surface 41g.

[0025] As shown in Fig. 4, the inner peripheral surface 41d2 of the main body member sealing 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. 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.

[0026] 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 detached from the outer shell, preventing 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 prevents an increase in the force required to pull out the inner bag 4 due to friction at the contact surface 51.

[0027] The inner peripheral surface 41b1 of the inner cylinder 41b is in close contact with the outer peripheral surface 4c7 of the protruding portion 4c. A contact surface 52 between the inner peripheral surface 41b1 of the inner cylinder 41b and the outer peripheral surface 4c7 of the protruding portion 4c is preferably inclined with respect to the axial direction. The inclination angle is, for example, 0.5 to 15 degrees (6.7 degrees in this embodiment), and preferably 3 to 10 degrees. Specific examples of the 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, 6.0, 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 within a range between any two of the values ​​exemplified here.

[0028] According to this configuration, 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.

[0029] As shown in FIG. 4, the discharge member 43 is attached to a tip portion 4c5 that protrudes from the main body member 41 through an insertion hole 41h of the protrusion 4c. More specifically, an engagement portion 4c6 is provided in the tip portion 4c5, and the discharge member 43 is attached to the tip portion 4c5 by engaging with the engagement portion 4c6. In this embodiment, the engagement portion 4c6 is a male thread portion 4c12 provided on the outer surface of the tip portion 4c5, and this male thread portion is threadedly engaged with a female thread portion 43b provided on the inner circumferential surface of the discharge member 43. The discharge member 43 may be attached to the tip portion 4c5 in a plug-type manner.

[0030] As shown in FIG. 4, the discharge member 43 includes a discharge member main body 45 and an overcap 46. The discharge member main body 45 includes a nozzle 45a and an engaging tube 45b. The nozzle 45a and the engaging tube 45b are connected to each other at 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 valve 42 is configured to allow the contents to be discharged while preventing outside air from entering the inner bag 4. The discharge port 45d can be closed using the overcap 46. When in use, the overcap 46 can be removed to open the discharge port 45d and discharge the contents.

[0031] 5, the open end 5c of the protrusion 4c has a reduced diameter portion 4c9 formed by bending a portion 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, 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 within a range between any two of the values ​​exemplified here.

[0032] If the thickness of the reduced diameter portion 4c9 at the inner circumferential surface 4c13 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, and 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.

[0033] A sealing member 44 is welded to an upper surface 4c10 of the reduced diameter portion 4c9. In one example, the sealing member 44 is configured by laminating a sealant layer and a gas barrier layer, and the sealant layer is welded to the upper surface 4c10. In one example, the gas barrier layer is an aluminum layer. By welding the sealing member 44 configured in this way to the upper surface 4c10 and closing the opening 4c11 of the open end 5c, 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 sealing member 44 can be peeled off, and then the discharge member 43 can be reattached to the tip portion 4c5.

[0034] 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 within a range between any two of the values ​​exemplified here.

[0035] <Air flow restriction member 53> 3B and 6, the container body 2 is provided with an outside air introduction hole 3h penetrating the outer shell 3, and an air flow restriction member 53 that restricts the flow of air through the outside air introduction hole 3h. The outside air introduction hole 3h is preferably provided in the bottom 7, and more preferably in the center of the bottom 7. Providing the outside air introduction hole 3h in this position not only makes the air flow restriction member 53 less noticeable, resulting in an excellent appearance, but also has the advantage that when an outside air introduction hole 13g (shown in FIG. 7) that serves as the outside air introduction hole 3h is provided in the outer preform 13, the outside air introduction hole 13g is less likely to deform during biaxial stretch blow molding.

[0036] 6A, the air flow restriction member 53 is welded or bonded to the outer shell 3 at a joint 53a. Attaching the air flow restriction member 53 to the outside air inlet hole 3h by a method such as engagement requires extremely high dimensional accuracy of the outside air inlet hole 3h, but it is not easy to increase the dimensional accuracy of the outside air inlet hole 3h. In contrast, in this embodiment, the air flow restriction member 53 is welded or bonded to the outer shell 3, so the air flow restriction member 53 can be positioned at a desired position to restrict the flow of air through the outside air inlet hole 3h without increasing the dimensional accuracy of the outside air inlet hole 3h.

[0037] When the outer shell 3 is pressed from the outside of the container body 2 to discharge the contents of the inner bag 4, the air flow restricting member 53 is configured to either allow air to flow out of the intermediate space between the outer shell 3 and the inner bag 4 to an extent that the pressure in the intermediate space increases to facilitate the discharge of the contents, or to not allow air to flow out. When pressure is stopped, the air flow restricting member 53 is configured to allow air to flow into the intermediate space from outside the container body 2 so that the shape of the outer shell 3 is restored.

[0038] Examples of the air flow restricting member 53 include a check valve 9 that restricts the flow of air as the moving body moves, and an air permeable membrane that allows a small amount of air flow. The air permeable membrane may be a microporous membrane made primarily of polytetrafluoroethylene (PTFE), for example, and the microporous membrane may be a composite of a nonwoven fabric and a polyethylene terephthalate (PET) mesh.

[0039] The check valve 9 has the function of preventing air from flowing out through the outside air introduction hole 3h while allowing air to flow in through the outside air introduction hole 3h. The check valve 9 includes a valve body 9a and a moving body 9b. The moving body 9b is configured to be movable within a space 9a3 within the valve body 9a. The space 9a3 includes a first opening 9a1 on the outside space side and a second opening 9a2 on the intermediate space side. The valve body 9a includes a first contact portion 9a4 that contacts the moving body 9b when it moves toward the outside space, and a second contact portion 9a5 that contacts the moving body 9b when it moves toward the intermediate space. When the moving body 9b contacts the first contact portion 9a4, air is prevented from flowing out through the openings 9a1 and 9a2. When the moving body 9b contacts the second contact portion 9a5, air is allowed to flow in through the openings 9a1 and 9a2.

[0040] The outside air introduction hole 3h is configured to accommodate at least a portion of the valve body 9a. The valve body 9a has a base 9a6 and a tip 9a7 protruding from the base 9a6. The tip 9a7 has a smaller outer diameter than the base 9a6, and a flat portion 9a8 is provided at the boundary between the base 9a6 and the tip 9a7. The outside air introduction hole 3h has, in order from the outer surface 3i side of the outer shell 3, a base 3h1 and a tip 3h2, and a flat portion 3h3 is provided at the boundary between the base 3h1 and the tip 3h2. The base 9a6 and the tip 9a7 are accommodated within the base 3h1 and the tip 3h2, respectively. The valve body 9a is welded or bonded to the outer shell 3. It is preferable that at least one (preferably two or three) of the base 9a6, the tip 9a7, and the flat portion 9a8 of the valve body 9a be welded or bonded. Furthermore, it is preferable that the valve body 9a is welded or bonded at least at the flat portion 9a8. In this case, welding or bonding can be easily performed by pressing the flat portion 9a8 of the valve body 9a against the flat portion 3h3. Welding is preferable to bonding because it does not require adhesive. Furthermore, ultrasonic welding is preferable for welding. As described above, in this embodiment, the valve body 9a, which is one of the components constituting the air flow restricting member 53, is welded or bonded to the outer shell 3.

[0041] <Use of double container 1> In this embodiment, the opening-mounted member 8 is provided with a discharge valve 42, which causes the inner bag 4 to contract as the contents of the inner bag 4 are discharged. Furthermore, an outside air inlet hole 3h is provided through the outer shell 3, allowing the inner bag 4 to separate from the outer shell 3 and contract as the contents are discharged, creating a peelable container. Furthermore, an air flow restriction member 53 is provided to restrict the flow of air through the outside air inlet hole 3h, so that when the outer shell 3 is compressed, the pressure in the intermediate space increases, 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, outside air is introduced into the intermediate space, allowing the outer shell 3 to quickly restore its original shape. Therefore, this embodiment makes it possible to create a squeeze-type peelable container.

[0042] <Pull out inner bag 4> Because the main body member 41 is engaged with the protruding portion 4c in the axial direction, the inner bag 4 can be pulled out of the container body 2 by pulling the main body member 41. Furthermore, if the main body member 41 is also engaged with the protruding portion 4c in the circumferential direction, the inner bag 4 can be twisted and reduced in diameter by rotating the main body member 41. This reduces the force required to pull out the inner bag 4.

[0043] 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 to be removed from the container body 2 as the inner bag 4 rotates. With this configuration, by rotating the main body member 41, the inner bag 4 can be moved in a direction to be removed from the container body 2 while twisting, and then the inner bag 4 can be pulled out of the container body 2 by pulling the main body member 41.

[0044] 1-2. Manufacturing method of double container 1 The container body 2 can be manufactured by a method including a biaxially stretched blow molding process and a cutting process. After the biaxially stretched blow molding process, a placement process can be performed in which the air flow restriction member 53 is placed. Furthermore, a process can be performed in which the mouth attachment member 8 is attached to the container body 2. The double container 1 can be manufactured by the above processes.

[0045] 1-2-1. Preform 15 As shown in FIGS. 7 and 8, 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.

[0046] As shown in Fig. 7, the inner preform 14 is cylindrical with a bottom and includes a mouth portion 14a, a body portion 14b, and a bottom portion 14c. The bottom portion 14c is provided so as to close the lower end of the body portion 14b. The mouth portion 14a is provided with a protruding portion 14d. As shown in Fig. 8, the protruding portion 14d is a portion of the preform 15 that protrudes from the open end 13f of the outer preform 13. The protruding portion 14d does not deform during molding and remains in its original shape to become the protruding portion 4c.

[0047] As shown in Figures 7 and 8, 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 protruding portion 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.

[0048] As shown in Fig. 7, the outer preform 13 is cylindrical with a bottom 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 of the outer preform 13 is provided with an outside air introduction hole 13g and an annular protrusion 13h that surrounds the outside air introduction hole 13g. The shape of the outside air introduction hole 13g hardly changes during biaxial stretch blow molding, and it has substantially the same shape as the outside air introduction hole 13h.

[0049] As shown in FIG. 8, 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-described 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.

[0050] 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.

[0051] 1-2-2. Biaxial stretch blow molding process The biaxial stretch blow molding process will be described with reference to Figures 8 to 10. In the biaxial stretch 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 stretch blow molded.

[0052] In one example, the biaxially stretched blow molding process includes a positioning step, a heating step, and a stretching step. Each step will be described below.

[0053] <Installation process> In the mounting step, as shown in FIGS. 8 and 9, the preform 15 is mounted 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.

[0054] 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 FIGS. 8 and 9, 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 abuts or is close to 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 a gap between the inner preform 14 and the blow core 21 during biaxial stretch blow molding is suppressed.

[0055] 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, 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, which has a small area, and the supporting state is likely to become unstable.

[0056] <Heating process> The heating process can be performed using a heating device 35 shown in FIG. 9. 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 near a heater 32 while the preform 15 is attached to a blow core 21, as shown in FIG. 9. 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.

[0057] <Stretching process> The stretching step can be performed using a blow molding apparatus 36 shown in Fig. 10. 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.

[0058] ·First stretching process 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, which is the vertical direction in FIG. 10. In one example, as shown in FIG. 10, 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 pressing a stretch rod 25 inserted through a through hole 21c provided in a 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 stretching of the stretch rod 25. This allows the preform 15 to be stably stretched.

[0059] 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 that corresponds 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 the opposing surface 23c that faces the flange 13d in the first axial direction.

[0060] ·Second stretching process 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 suppressing the occurrence of molding defects.

[0061] Through the above steps, a molded body 2a having a structure in which the extension 14f is connected to the container body 2 as shown in FIG. 12 is obtained.

[0062] In the method of this embodiment, as shown in FIGS. 10 and 11 , biaxial stretch blow molding is performed while the bottom 13c of the outer preform 13 is supported by a bottom support mold 22, thereby suppressing deformation of the outside air introduction hole 13g. Furthermore, an annular convex portion 13h is provided surrounding the outside air introduction hole 13g, and the bottom support mold 22 is configured to suppress extension of the annular convex portion 13h, further suppressing deformation of the outside air introduction hole 13g. In one example, the bottom support mold 22 has an annular convex portion 22a, which supports the bottom 13c so that the inner peripheral surface of the annular convex portion 22a is in close proximity to or in contact with the outer peripheral surface of the annular convex portion 13h. With this configuration, the inner peripheral surface of the annular convex portion 22a is in close proximity to or in contact with the outer peripheral surface of the annular convex portion 13h, thereby suppressing deformation of the annular convex portion 13h. Furthermore, the bottom support mold 22 has a protrusion 22b that is inserted into the outside air introduction hole 13g. Since the temperature of the protrusions 22b is usually lower than that of the bottom portion 13c, by bringing the protrusions 22b into contact with the inner surface of the outside air introduction hole 13g, deformation of the outside air introduction hole 13g is further suppressed.

[0063] 1-2-3. Excision process In the cutting step, after the biaxially stretch blow molding step, the extension 14f is cut off along dotted line 47 as shown in Fig. 12. This results in the container body 2 having the structure shown in Fig. 5. After the cutting step, the opening end 5c is provided with a reduced diameter portion 4c9 formed by bending a portion adjacent to the opening end 5c radially inward. The outside air introduction hole 13g of the outer preform 13 becomes the outside air introduction hole 3h of the outer shell 3.

[0064] 1-2-4. Placement process In the placement step, as shown in FIG. 6, an air flow restriction member 53 is placed after biaxial stretch blow molding to restrict the flow of air through the outside air introduction hole 3h. In the method of this embodiment, deformation of the outside air introduction hole 13g is suppressed, and the shape of the outside air introduction hole 13g and the shape of the outside air introduction hole 3h are approximately the same, thereby suppressing problems associated with deformation of the outside air introduction hole 13g. In one example, as shown in FIG. 6, the air flow restriction member 53 is a check valve 9. The check valve 9 includes a valve body 9a and a movable body 9b that is movable within a space 9a3 within the valve body 9a. The outside air introduction hole 3h is configured to accommodate at least a portion of the valve body 9a. According to the method of this embodiment, deformation of the outside air introduction hole 13g during biaxial stretch blow molding is suppressed, thereby suppressing problems that may occur when inserting the valve body 9a into the outside air introduction hole 3h.

[0065] Preferably, the container body 2 formed by a method including a biaxial stretch blow molding process includes an inner bag 4 and an outer shell 3 arranged to cover the inner bag 4, and the air flow restricting member 53 is arranged by welding or adhering at least one of the components constituting the air flow restricting member 53 to the outer shell 3. In this case, the air flow restricting member 53 is arranged more stably. In one example, the valve body 9a is welded or adhered to the outer shell 3 at the joint 53a. In the present and second embodiments, the air flow restricting member 53 is arranged by attaching a completed check valve 9. However, as in the third and fourth embodiments, the outer shell 3 may constitute a part of the check valve 9, and the air flow restricting member 53 may be arranged by welding or adhering other components of the check valve 9 to the outer shell 3 to complete the check valve 9. Note that, in the invention from the viewpoint of being able to suppress deformation of the outside air introduction hole 13g during biaxial stretch blow molding, the above-mentioned welding or adhering is not essential. In this case, the air flow restriction member 53 may be attached to the outside air introduction hole 3h by press-fitting or engagement.

[0066] 1-2-5. Content filling process and sealing process The cutting step may be followed by a content filling step and a sealing step, in this order. In the content filling step, the container body 2 is filled with content. Examples of the content include mayonnaise and sauce. In the sealing step, 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.

[0067] 2. Second embodiment A second embodiment of the present invention will be described with reference to Figure 13. This embodiment is similar to the first embodiment, and the details described in the first embodiment can also be applied to this embodiment as long as they do not contradict the spirit of the first embodiment. This embodiment differs mainly from the first embodiment in the configuration of the air flow restriction member 53. The following description will focus on these differences.

[0068] In this embodiment, the valve body 9a includes a cylindrical portion 9c having a space 9a3 and a flange portion 9d protruding radially from the cylindrical portion 9c. The flange portion 9d is welded or bonded to the outer shell 3 at a joint portion 53a. With this configuration, if the outside air introduction hole 3h is smaller than the flange portion 9d, the valve body 9a can be welded or bonded to the outer shell 3. In this embodiment, the flange portion 9d of the valve body 9a, which is one of the components constituting the air flow restriction member 53, is welded or bonded to the outer shell 3.

[0069] The cylindrical portion 9c is preferably inserted into the outside air introduction hole 3h. In this case, there is an advantage that the cylindrical portion 9c does not protrude outward from the flange portion 9d. The outside air introduction hole 3h only needs to be sufficiently large compared to the outer shape of the cylindrical portion 9c, and there is no need to increase the dimensional accuracy of the outside air introduction hole 3h. Such an outside air introduction hole 3h may be formed after biaxial stretch blow molding of the container body 2, or may originate from the outside air introduction hole 13g provided in the outer preform 13. The outside air introduction hole 13g of the outer preform 13 is prone to deformation during biaxial stretch blow molding. However, in this embodiment, the dimensional accuracy of the outside air introduction hole 3h does not need to be high, so deformation during biaxial stretch blow molding does not pose a problem.

[0070] 3. Third embodiment A third embodiment of the present invention will be described with reference to Figure 14. This embodiment is similar to the first embodiment, and the details described in the first embodiment can also be applied to this embodiment as long as they do not contradict the spirit of the first embodiment. This embodiment differs mainly from the first embodiment in the configuration of the air flow restriction member 53. The following description will focus on these differences.

[0071] In this embodiment, the air flow restriction member 53 is a check valve 9 and includes a valve body 9a and a movable body 9b. The valve body 9a is configured by combining a first member 9aa and a second member 9ab. The first member 9aa has an opening 9a9 through which the movable body 9b can pass without deforming the first member 9aa. The second member 9ab has an air vent 9ab1 through which the movable body 9b cannot pass, and is welded or bonded to the first member 9aa at a joint 53a so that the air vent 9ab1 communicates with the opening 9a9. The first member 9aa is configured by the outer shell 3. Therefore, in this embodiment, the second member 9ab, which is one of the members that configure the air flow restriction member 53, is welded or bonded to the outer shell 3.

[0072] That is, in this embodiment, the portion of the outer shell 3 including the outside air introduction hole 3h is cylindrical and functions as the first member 9aa. The movable body 9b can be inserted into the space 9a3 of the first member 9aa through the opening 9a9. Since no force is applied to either the first member 9aa or the movable body 9b when the movable body 9b is inserted, deformation of the first member 9aa and the movable body 9b is suppressed. After the second member 9ab is welded or bonded to the first member 9aa (i.e., the outer shell 3), the movable body 9b is suppressed from separating from the space 9a3. Furthermore, outside air can be introduced into the intermediate space through the ventilation hole 9ab1. Furthermore, the second member 9ab is provided with a first abutment portion 9a4.

[0073] In the method of this embodiment, the first abutment portion 9a4, which requires high dimensional accuracy, is provided on the second member 9ab, which is separate from the outer shell 3, so that it is possible to regulate the flow of air through the outside air introduction hole 3h without increasing the dimensional accuracy of the outside air introduction hole 3h.

[0074] 4. Fourth embodiment A fourth embodiment of the present invention will be described with reference to Figure 15. This embodiment is similar to the third embodiment, and the details described in the third embodiment can also be applied to this embodiment as long as they do not contradict the spirit of the third embodiment. This embodiment differs mainly from the third embodiment in the configuration of the air flow restriction member 53. The following description will focus on these differences.

[0075] In the third embodiment, the first member 9aa is formed by the outer shell 3, but in the present embodiment, the second member 9ab is formed by the outer shell 3. Therefore, in the present embodiment, the first member 9aa, which is one of the members forming the air flow restricting member 53, is welded or adhered to the outer shell 3.

[0076] As described above, in this embodiment, the portion of the outer shell 3 including the outside air introduction hole 3h functions as the second member 9ab. After the second member 9ab, which is made up of the outer shell 3, is welded or bonded to the first member 9aa at the joint 53a, the moving body 9b is prevented from separating from the space 9a3. Furthermore, outside air can be introduced into the intermediate space through the air vent 9ab1. Furthermore, the first member 9aa is provided with a first abutment portion 9a4. The first member 9aa preferably includes a cylindrical portion 9c having the space 9a3 and a flange portion 9d protruding radially from the cylindrical portion 9c, and the flange portion 9d is preferably welded or bonded. In this case, the first member 9aa is stably welded or bonded.

[0077] In the method of this embodiment, the first abutment portion 9a4, which requires high dimensional accuracy, is provided on the first member 9aa, which is separate from the outer shell 3, so that it is possible to regulate the flow of air through the outside air introduction hole 3h without increasing the dimensional accuracy of the outside air introduction hole 3h.

[0078] 5. Other embodiments The shape of the mouth 5 of the container body 2 is not particularly limited and may be a shape other than that shown in the above embodiment. The extension 14f can be omitted if it is not required, in which case the cutting step can also be omitted. Furthermore, the content filling step and the sealing step can also be omitted if they are not required.

Description of Symbols

[0079] 1: Double container 2: Container body 2a: Formed body 3: Outer shell 3a: Open end 3a3: Inner bag support surface 3f1: Second flange portion 3f2: Second flange portion 3g4: Outer peripheral surface 3h: Outside air introduction hole 3h1: Base portion 3h2: Tip portion 3h3: Flat portion 3i: Outer surface 4: Inner bag 4a: First cylinder 4b: Second cylinder 4b4: Bottom surface 4c: Protrusion 4c10: Top surface 4c11: Opening 4c12: Male screw portion 4c13: Inner peripheral surface 4c3: Engaging portion 4c5: Tip part 4c6: Engaging portion 4c7: Outer peripheral surface 4c9: Diameter-reduced portion 4d: Inner bag body 5: Mouth portion 5c: Open end 6: Barrel portion 6b: Shoulder portion 6c: Barrel body 7: Bottom portion 8: Mouth portion mounting member 9: Check valve 9a: Valve body 9a1: First opening 9a2: Second opening 9a3: Space 9a4: First contact portion 9a5: Second contact portion 9a6: Base portion 9a7: Tip portion 9a8: Flat part 9a9 :Aperture 9aa: First member 9ab: Second member 9ab1: Ventilation hole 9b: Mobile object 9c:Cylinder part 9d: Flange part 13: Outer preform 13a: Mouth 13b: Torso 13c: Bottom 13d: Flange 13f: Open end 13g: Outside air intake 13h: Annular convex part 14: Inner preform 14a: Mouth 14b: Torso 14c: Bottom 14d:Protrusion 14e: Part 14f: Extension part 14g: Open end 14h: Expanded diameter part 14i: Reduced diameter part 14j: Inclined part 15: Preform 15a: Mouth 15b: Body 15c: bottom 21: Blow Core 21a: base 21b: Insertion part 21c: Through hole 21g: Tip 21h: Reduced diameter part 21i: Inclined part 21j: Expanded diameter part 22: Bottom support type 22a: Annular convex part 22b: Protrusion 23: Molding mold 23a: Cavity surface 23b: flange housing 23c: Opposite surface 25: Stretching rod 32: Heater 33: Heat shielding section 35: Heating device 36: Blow molding equipment 41: Main body member 41b: Inner cylinder 41b1: Inner peripheral surface 41d: Main body member seal tube 41d2: Inner peripheral surface 41d4: Engagement protrusion 41g:Top part 41h: Insertion hole 42: Discharge valve 43: Discharge member 43a:Discharge port 43b: Female thread 44: Sealing material 45: Discharge member body 45a: Nozzle 45b: Engagement tube 45c: Top part 45d:Discharge port 46: Overcap 47:Dotted line 51: Contact surface 52: Contact surface 53: Air flow control member 53a: Joint C: Central axis T:Thickness

Claims

1. A double container comprising a container body, the container body is a biaxially stretched blow molded article, The container body includes an inner bag and an outer shell disposed to cover the inner bag, the container body is provided with an outside air introduction hole penetrating the outer shell and an air flow regulation member that regulates the flow of air through the outside air introduction hole, The air flow regulating member is a double container, wherein at least one of the members constituting the air flow regulating member is welded or bonded to the outer shell.

2. The double container according to claim 1, The air flow restriction member includes a valve body and a moving body, The movable body is configured to be movable within a space within the valve body, The valve body includes a cylindrical portion having the space and a flange portion protruding radially from the cylindrical portion, The flange portion is welded or bonded to the outer shell.

3. The double container according to claim 2, The double container, wherein the cylindrical portion is inserted into the outside air introduction hole.

4. The double container according to claim 1, The air flow restriction member includes a valve body and a moving body, The movable body is configured to be movable within a space within the valve body, The valve body is configured by combining a first member and a second member, the first member has an opening through which the movable body can pass without deforming the first member; the second member has an air hole through which the movable body cannot pass, and is welded or adhered to the first member so that the air hole communicates with the opening; A double container, wherein the first member or the second member is constituted by the outer shell.

5. A method for manufacturing a double-layered container, comprising a biaxially stretched blow molding step and a placement step, In the biaxially stretched blow molding step, the preform is biaxially stretched blow molded, The preform is configured by covering an outer preform with an inner preform, the outer preform has an outside air introduction hole at its bottom that penetrates the outer preform, The biaxial stretch blow molding is performed in a state where the bottom is supported by a bottom support mold, In the arranging step, an air flow regulating member for regulating the flow of air through the outside air introduction hole is arranged after the biaxially stretch blow molding.

6. 6. The method of claim 5, The container body formed by the method including the biaxial stretch blow molding step includes an inner bag and an outer shell disposed to cover the inner bag, The method of claim 1, wherein the air flow restriction member is disposed by welding or adhering at least one of the components that make up the air flow restriction member to the outer shell.

7. 6. The method of claim 5, the outer preform has an annular protrusion surrounding the outside air introduction hole, The method, wherein the bottom support mold is configured to constrain extension of the annular protrusion.

8. The method according to any one of claims 5 to 7, the air flow restriction member is a check valve, The check valve includes a valve body and a movable body that is movable within a space within the valve body, The method, wherein the outside air inlet is configured to accommodate at least a portion of the valve body.

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