Dual container

Abstract

Provided is a dual container from which an inner bag can be easily pulled out of an outer shell. According to the present invention, a dual container is provided, having a container body and a mouth portion mounting member, the container body having a mouth portion, a body portion, and a bottom portion, the mouth portion being a cylindrical portion having an open end, the body portion being disposed adjacent to the mouth portion on a side further from the open end than the mouth portion, and the body portion having an outer diameter larger than an outer diameter of the mouth portion, the bottom portion being configured to close a lower end of the body portion, the container body having an inner bag and an outer shell disposed so as to cover the inner bag, the mouth portion mounting member being configured to be mountable to the mouth portion, and being configured such that the inner bag rotates with rotation of the mouth portion mounting member.

Description

Technical Field

[0001] This invention relates to a preform, a dual container, and a method for manufacturing the same. Background Technology

[0002] Conventionally, dual containers with a main body consisting of an outer shell and an inner bag are known. For example, Patent Documents 1 and 2 disclose a dual container formed by biaxial stretch blow molding with an outer preform overlapping an inner preform.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-10741

[0006] Patent Document 2: WO2004 / 071887 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] However, in cases where the outer shell and inner bag of such a double container are made of different materials, or where the contents are attached to the inner bag after use, it is desirable to separate the outer shell and inner bag when recycling the double container.

[0009] (First viewpoint and second viewpoint)

[0010] The present invention was made in view of the following situation, providing a double container in which the inner bag can be easily pulled out from the outer shell.

[0011] (Third perspective)

[0012] To facilitate separation of the inner bag from the outer shell, it is preferable to loosely fit the inner bag to the outer shell at the opening of the container body, without securing it tightly. However, in this case, the inner bag becomes susceptible to relative rotation with respect to the outer shell at the opening of the container body. After filling the container body with contents, if a mouth-mounting member (cap or pump, etc.) with an inner ring is screwed onto the opening of the container body, friction between the inner ring and the inner surface of the opening can sometimes cause the opening of the inner bag to rotate along with the cap, resulting in the inner bag twisting. If the inner bag twists, the contents inside the inner bag may spill out.

[0013] The present invention was made in view of the following circumstances, providing a dual container that suppresses inner bag torsion when installing a mouth mounting member with an inner ring and allows the inner bag to be easily pulled out from the outer shell after use.

[0014] (Fourth viewpoint)

[0015] The inventors of this invention have learned that in a reference example where homopolymer polypropylene is used as the material for the inner preform and amorphous PET (polyethylene terephthalate) is used as the material for the outer preform, biaxial stretch blow molding is performed with the inner and outer preforms overlapping to produce a double container. In this case, the following phenomenon sometimes occurs: the inner bag of the double container shrinks when cooled, creating a gap between the inner bag and the outer shell, resulting in the inner bag containing less than the specified amount.

[0016] The present invention was made in view of the following circumstances, and provides a preform that can suppress inner bag shrinkage during cooling after molding.

[0017] (Fifth viewpoint)

[0018] The outer shell and inner bag can be separated by the user pulling the inner bag out of the outer shell, but the user has difficulty deciding how to handle the separated inner bag.

[0019] The present invention was made in view of the following circumstances, providing a dual container that improves the handleability of the inner bag after separation from the outer shell.

[0020] (Sixth to Eighth Viewpoints)

[0021] The outer shell and inner bag can be separated by the user pulling the inner bag out of the outer shell, but it is desirable to reduce the force required for this pull-out.

[0022] The present invention was made in view of the following situation, providing a dual container that can reduce the force required to pull out the inner bag.

[0023] (Ninth viewpoint)

[0024] Imagine that the outer shell and inner bag can be separated by pulling the inner bag out of the outer shell, and it is desirable that the inner bag can be easily pulled out of the outer shell.

[0025] The present invention was made in view of the following circumstances, providing a double container in which the inner bag can be easily pulled out from the outer shell.

[0026] (Tenth viewpoint)

[0027] The outer shell and inner bag can be separated by the user pulling the inner bag out of the outer shell, which aims to reduce the force required to pull out the inner bag.

[0028] In addition, to prevent the deterioration of the contents, it is desirable to improve the gas barrier properties in the inner bag. If an EVOH layer with excellent gas barrier properties is placed in the inner bag, the gas barrier properties can be improved, but the inner bag will become stiff and the pull-out properties of the inner bag will deteriorate.

[0029] The present invention was made in view of the following circumstances, providing a dual container that suppresses the deterioration of the pull-outability of the inner bag and improves the air barrier properties of the inner bag.

[0030] means for solving problems

[0031] (First viewpoint)

[0032] According to the present invention, a dual container is provided having a container body and a mouth mounting member. The container body has a mouth, a body, and a bottom. The mouth is a cylindrical portion with an open end. The body is disposed adjacent to the mouth on a side further away from the open end than the mouth, and the outer diameter of the body is larger than the outer diameter of the mouth. The bottom is configured to close the lower end of the body. The container body has an inner bag and an outer shell disposed to cover the inner bag. The mouth mounting member is configured to be mounted on the mouth, and the inner bag is configured to rotate with the rotation of the mouth mounting member.

[0033] In the double container of the present invention, the inner bag is configured to rotate with the rotation of the opening mounting member, thus the inner bag can be twisted by rotating the opening mounting member. The outer diameter of the body of the container body is larger than the outer diameter of the opening, so it is not easy to pull the inner bag out through the opening by simply stretching it. However, by twisting the inner bag and narrowing the diameter of the body, the body of the inner bag becomes easier to pass through the opening of the outer shell, and the inner bag can be easily pulled out from the outer shell.

[0034] The following examples illustrate various embodiments of the present invention. These embodiments can be combined with each other.

[0035] Preferably, in the described double container, the inner bag has a protrusion that protrudes from the open end of the outer shell. The protrusion has a protruding cylinder and a locking protrusion that protrudes radially outward from the circumferential surface of the protruding cylinder. The locking protrusion is configured to engage with the claw portion of the mouth mounting member in the rotational direction of the mouth mounting member, thereby causing the inner bag to rotate along with the rotation of the mouth mounting member.

[0036] Preferably, in the described double container, the protrusion has an engaging flange at a position farther from the opening end than the engaging protrusion, the engaging flange engaging with the claw portion of the opening mounting member in the axial direction of the opening, thereby allowing the inner bag to be pulled out from the outer shell as the opening mounting member is moved in a direction away from the opening end.

[0037] Preferably, in the described dual container, the protrusion has an abutting flange that abuts against the open end, and the engaging protrusion is disposed between the abutting flange and the engaging flange.

[0038] Preferably, in the described double container, at least one of the inner surfaces of the opening and the body adjacent to the opening is provided with a concave-convex shape, the concave-convex shape being a shape in which concave strips and convex strips alternate in the circumferential direction of the opening, the concave strips and the convex strips extending non-parallel in the circumferential direction of the opening.

[0039] Preferably, a dual container has a container body having a mouth, a body, and a bottom. The mouth is a cylindrical portion with an open end. The body is disposed adjacent to the mouth on a side further away from the open end than the mouth, and the outer diameter of the body is larger than the outer diameter of the mouth. The bottom is configured to close the lower end of the body. The container body has an inner bag and an outer shell disposed to cover the inner bag. At least one of the mouth and the body adjacent to the mouth has a concave-convex shape, which is a shape in which concave strips and convex strips alternate in the circumferential direction of the mouth, and the concave strips and convex strips extend non-parallel in the circumferential direction of the mouth.

[0040] (Second viewpoint)

[0041] According to the present invention, a dual container is provided, having a container body having a mouth, a body, and a bottom. The mouth is a cylindrical portion with an open end. The body is disposed adjacent to the mouth on a side further away from the open end than the mouth, and the outer diameter of the body is larger than the outer diameter of the mouth. The bottom is configured to close the lower end of the body. The container body has an inner bag and an outer shell disposed to cover the inner bag. An alternating wall thickness shape is provided at the bottom of the inner bag, the alternating wall thickness shape being a shape in which thin-walled portions and thick-walled portions with a wall thickness greater than the thin-walled portions alternate in the circumferential direction.

[0042] The outer diameter of the container body is larger than that of the opening. Therefore, it is difficult to pull the inner bag through the opening simply by stretching it. However, by twisting the inner bag and narrowing its diameter, the inner bag can easily pass through the opening of the outer shell. On the other hand, in conventional double containers, even if the inner bag is simply twisted, it is difficult to narrow the bottom diameter, making it difficult to pull the bottom out of the opening.

[0043] In the double container of the present invention, the bottom of the inner bag is provided with an alternating wall thickness shape consisting of thin-walled and thick-walled portions that alternate in the circumferential direction. With such a shape, selective bending easily occurs in the thin-walled portions when the inner bag is twisted, resulting in the bottom of the inner bag deforming into a corrugated shape and becoming prone to diameter reduction. Therefore, in the double container of the present invention, the bottom easily narrows when the inner bag is twisted, thus allowing the inner bag to be easily pulled out from the outer shell.

[0044] The following examples illustrate various embodiments of the present invention. These embodiments can be combined with each other.

[0045] Preferably, in the described double container, the bottom of the inner bag is provided with a bottom recessed region and a peripheral region surrounding the bottom recessed region, and the alternating wall thickness shape is provided on at least one of the peripheral surface of the bottom recessed region and the peripheral region.

[0046] Preferably, in the described dual container, the alternating wall thickness shape is configured to span across the circumferential surface and the peripheral region.

[0047] Preferably, in the described dual container, the alternating wall thickness shape is configured to span across the peripheral region and the side of the inner bag.

[0048] Preferably, in the described double container, the thin-walled portion is formed by providing a recessed strip on one or both of the inner and outer surfaces of the inner bag.

[0049] Preferably, in the described double container, in the cross-section of the inner bag perpendicular to the height direction, if the wall thickness of the inner bag at the thin-walled portion is set as T1 and the wall thickness of the inner bag at the thick-walled portion is set as T2, then the minimum value of T1 / T2 is 0.8 or less.

[0050] (Third perspective)

[0051] According to the present invention, a dual container is provided having a container body having a mouth, a body, and a bottom. The mouth is a cylindrical portion having an open end. The body is disposed adjacent to the mouth on a side further away from the open end than the mouth, and the outer diameter of the body is larger than the outer diameter of the mouth. The bottom is configured to close the lower end of the body. The container body has an inner bag and an outer shell disposed to cover the inner bag. At the mouth, a first resistance to relative rotation of the inner bag relative to the outer shell in one direction is greater than a second resistance to relative rotation in another direction.

[0052] In the dual-container of the present invention, at the opening of the container body, the first resistance to the relative rotation of the inner bag with respect to the outer shell in one direction is greater than the second resistance to the relative rotation in the other direction. Therefore, by using one direction as the fastening direction of the opening mounting member, the torsion of the inner bag is suppressed when installing the opening mounting member. When separating the inner bag from the outer shell after use, by rotating the opening of the inner bag relative to the outer shell in the other direction, the inner bag can be easily twisted and its diameter reduced, thereby making it easy to pull the inner bag out of the outer shell.

[0053] The following examples illustrate various embodiments of the present invention. These embodiments can be combined with each other.

[0054] Preferably, in the described double container, the opening has a right-hand threaded external thread, and the one direction and the other direction are respectively clockwise and counterclockwise when viewed from the upper side of the container body.

[0055] Preferably, the described double container has a mouth mounting member having an internal thread that can engage with the external thread of the mouth, wherein one direction is the fastening direction of the mouth mounting member and the other direction is the loosening direction of the mouth mounting member.

[0056] Preferably, in the described double container, the inner bag and the outer shell are engaged at the opening, wherein the engagement is configured such that the first resistance is greater than the second resistance.

[0057] Preferably, in the described dual container, the interlocking is an engagement between a protrusion on the outer peripheral surface of the inner bag and a recess on the inner peripheral surface of the outer shell.

[0058] Preferably, in the described dual container, the recess of the convex-concave engagement is formed by a groove, and the convex-concave engagement can be released by moving the protrusion of the convex-concave engagement along the groove.

[0059] Preferably, in the described dual container, the inclination angle of the groove is consistent with the inclination angle of the thread teeth of the external thread portion provided at the opening.

[0060] Preferably, a method for manufacturing a dual container includes a biaxial extension blow molding process, in which a preform consisting of an outer preform covering an inner preform is heated and biaxially extended blow molded to form a container body, wherein the inner preform and the outer preform engage in a concave-convex engagement at the opening of the preform.

[0061] (Fourth viewpoint)

[0062] According to the present invention, a preform is provided, which is formed by an outer preform covering an inner preform. The inner preform has a polyolefin layer made of a polyolefin resin containing a polyolefin, and the outer preform has an amorphous PET layer made of an amorphous PET resin containing amorphous PET. If the temperature range between the crystallization peak temperature and the melting peak temperature of the polyolefin resin is set as a first temperature range, and the temperature range between the softening end temperature and the crystallization start temperature of the amorphous PET resin is set as a second temperature range, then the overlapping temperature range of the first temperature range and the second temperature range is 2°C or more.

[0063] In the aforementioned reference example, after analyzing why the inner bag easily shrinks during cooling after molding, it was found that the reason is that at the molding temperature in the reference example, the amorphous PET is in a softened state suitable for molding, but the homopolymer polypropylene is in an insufficiently softened state. That is, it was found that the homopolymer polypropylene constituting the inner preform was molded in an insufficiently softened state, therefore, the inner bag becomes prone to shrinkage during cooling after molding.

[0064] Furthermore, further analysis revealed that homopolymer polypropylene, like other polyolefins, is in a softened state suitable for molding within the first temperature range, while amorphous PET is in a softened state suitable for molding within the second temperature range. Within the overlapping temperature range where the first and second temperature ranges coincide, both the polyolefin and amorphous PET are in a softened state suitable for molding. It was also found that, in both homopolymer polypropylene and amorphous PET, because the overlapping temperature range is a very narrow range of approximately 1°C, molding at suitable temperatures for both is not easy.

[0065] On the other hand, in the preform of the present invention, the overlap temperature range is 2°C or higher. Therefore, compared with the case of the above-mentioned reference example, it is easier to perform molding at a molding temperature where both the polyolefin and amorphous PET are in a softened state suitable for molding, and as a result, it is possible to suppress inner bag shrinkage during cooling after molding.

[0066] The following examples illustrate various embodiments of the present invention. These embodiments can be combined with each other.

[0067] Preferably, in the described preform, the polyolefin comprises a propylene copolymer, which is a copolymer of propylene and other monomers.

[0068] Preferably, in the described preform, the polyolefin comprises homopolymer polypropylene, and also comprises low-density polyethylene or linear low-density polyethylene.

[0069] Preferably, in the preform described, the overlap temperature range is 10°C or higher.

[0070] Preferably, a method for manufacturing a dual container involves using the described preform, heating the preform to a temperature within the overlapping temperature range, and performing biaxial stretch blow molding.

[0071] (Fifth viewpoint)

[0072] According to the present invention, a dual container is provided having a container body having an inner bag and an outer shell configured to cover the inner bag, the inner bag being detachable from the outer shell, and an information transmission display being printed on the inner bag by laser irradiation.

[0073] In the structure of this invention, an information transmission display is printed on the inner bag, which is configured to be detachable from the outer shell, by laser irradiation. The "information transmission display" is a display for conveying information, for example, consisting of patterns or text. Therefore, for example, by attaching an information transmission display to the inner bag showing its material or recycling method, the user can easily determine how to handle the detached inner bag. Thus, the handleability of the inner bag detached from the outer shell is improved.

[0074] The following examples illustrate various embodiments of the present invention. These embodiments can be combined with each other.

[0075] Preferably, in the described double container, a laser marking agent is prepared in the inner bag, the laser marking agent being a substance that absorbs laser light more readily than the resin constituting the inner bag and / or is more likely to change color due to laser absorption than the resin constituting the inner bag.

[0076] (Sixth point of view)

[0077] According to the present invention, a dual container is provided having an inner bag and an outer shell. The container body has a mouth, a body, and a bottom. The mouth is a cylindrical portion with an open end. The body is disposed adjacent to the mouth on a side further away from the open end than the mouth, and the outer diameter of the body is larger than the outer diameter of the mouth. The bottom is configured to close the lower end of the body. The body has a shoulder whose outer diameter increases as it moves away from the mouth. In the shoulder of the container body, at least one of the outer surface of the inner bag and the inner surface of the outer shell is provided with a concave-convex shape to reduce the contact area between the outer surface of the inner bag and the inner surface of the outer shell.

[0078] In the dual-container of the present invention, at least one of the outer surface of the inner bag and the inner surface of the outer shell is provided at the shoulder of the container body to reduce the contact area between the outer surface of the inner bag and the inner surface of the outer shell. The shoulder is a portion whose outer diameter increases with distance from the opening; therefore, when the inner bag is pulled out of the outer shell, the outer surface of the inner bag presses particularly forcefully against the inner surface of the outer shell at the shoulder. Thus, by providing the aforementioned uneven shape at the shoulder, the force required to pull out the inner bag can be effectively reduced.

[0079] The following examples illustrate various embodiments of the present invention. These embodiments can be combined with each other.

[0080] Preferably, in the described double container, if the convex and concave shape is set as a first convex and concave shape, then the other of the outer surface of the inner bag and the inner surface of the outer shell is not provided with a convex and concave shape, or a second convex and concave shape that is not a complementary shape to the first convex and concave shape is provided.

[0081] Preferably, a method for manufacturing a dual container includes a step of manufacturing a container body by biaxial extension blow molding of a preform consisting of an inner preform and an outer preform, wherein after the biaxial extension blow molding, at least one of the outer surface of the inner preform and the inner surface of the outer preform is provided with a concave-convex shape at the shoulder portion that becomes the container body.

[0082] Preferably, in the described method, the concave-convex shape is provided on the outer surface of the inner preform.

[0083] Preferably, in the described method, the convex and concave shape is formed by transferring the convex and concave shape formed on the mold by sandblasting onto the inner preform or the outer preform.

[0084] (Seventh viewpoint)

[0085] According to the present invention, a dual container is provided having a container body having an inner bag and an outer shell, wherein an easily expandable portion is provided at the opening of the outer shell, and the easily expandable portion facilitates the expansion of the opening of the outer shell when the inner bag is pulled out from the outer shell.

[0086] In the dual-container of the present invention, the aforementioned expandable portion is provided at the opening of the outer shell. Therefore, when the inner bag is pulled out from the outer shell, the opening of the outer shell is expanded, thereby reducing the force required to pull out the inner bag.

[0087] The following examples illustrate various embodiments of the present invention. These embodiments can be combined with each other.

[0088] Preferably, in the described double container, the expandable diameter portion is formed by a slit provided at the opening of the outer shell.

[0089] Preferably, in the described dual container, the expandable diameter portion is provided in the opening of the outer shell at multiple locations that are separated in the circumferential direction.

[0090] Preferably, in the described dual container, the dual container has a diameter expansion suppression part that suppresses the diameter expansion of the opening of the outer shell before the inner bag is pulled out.

[0091] Preferably, in the described double container, the inner bag has the flange, and the expansion-restraining portion is formed by the flange engaging with the open end of the outer shell.

[0092] (Eighth viewpoint)

[0093] According to the present invention, a dual container is provided, having a container body having an inner bag and an outer shell, the container body having a mouth, a body and a bottom, the mouth being a cylindrical portion having an open end, the body being disposed adjacent to the mouth on a side further away from the open end than the mouth, and the outer diameter of the body being larger than the outer diameter of the mouth, the bottom being configured to close the lower end of the body, the body having a curved portion that bends outward, and if the diameter of the container body at the portion with the smallest radius of curvature in the curved portion is set as D, and the radius of curvature is set as R, then R / D is 0.5 or more.

[0094] In conventional double-sided containers, a curved section with a small radius of curvature is provided in the body of the container. Near this curved section, the inner bag presses forcefully against the outer shell, thus increasing the force required to pull out the inner bag. In this embodiment, since the radius of curvature (R / D) is 0.5 or higher, the curved section is gentle, preventing the inner bag from pressing against the outer shell near the curved section and reducing the force required to pull out the inner bag.

[0095] The following examples illustrate various embodiments of the present invention. These embodiments can be combined with each other.

[0096] Preferably, in the described double container, the body has a shoulder whose outer diameter increases as it moves away from the opening, and the shoulder has an inclination angle of 25 degrees or less relative to the central axis of the opening.

[0097] Preferably, in the described double container, if the inner diameter of the opening of the outer shell is D2, then D / D2 is 1.8 or less.

[0098] Preferably, in the described double container, on the side of the body closer to the bottom than the curved portion, there is a tapered portion that tapers towards the bottom.

[0099] Preferably, in the described double container, if the diameter at the bottom surface of the recess provided at the bottom is set as D3 and the inner diameter of the opening of the outer shell is set as D2, then D3 / D2 is 0.6 or less.

[0100] (Ninth viewpoint)

[0101] According to the present invention, a dual container is provided having a container body having an inner bag and an outer shell, wherein the inner bag moves in a direction to be pulled out from the outer shell by rotating the inner bag relative to the outer shell.

[0102] In a container body having an inner bag and an outer shell, if the inner bag is completely pressed against the outer shell, there is no opportunity to pull it out, making it difficult to remove the inner bag from the outer shell. In the double container of the present invention, if the inner bag is rotated relative to the outer shell, the inner bag moves in the direction of being pulled out from the outer shell, and correspondingly, the inner bag rises from the outer shell. Using the rising portion as an opportunity, the inner bag can be pulled out from the outer shell. Therefore, the double container of the present invention makes it easy to pull the inner bag out from the outer shell.

[0103] The following examples illustrate various embodiments of the present invention. These embodiments can be combined with each other.

[0104] Preferably, in the described double container, the inner bag is movable via a cam mechanism.

[0105] Preferably, in the described dual container, the cam mechanism is disposed on the outer peripheral surface of the inner bag and the inner peripheral surface of the outer shell.

[0106] Preferably, in the described double container, the double container further has a mouth mounting member having a main body and a strap, the main body and the strap being connected to each other via a tear-resistant connector, the strap engaging with the mouth of the outer shell in both the circumferential and axial directions, the main body engaging with the mouth of the inner bag in both the circumferential and axial directions, and the strap being configured to be detachable from the main body by tearing the connector.

[0107] (Tenth viewpoint)

[0108] According to the present invention, a dual container is provided, having a container body having an inner bag and an outer shell, the container body being a biaxially extended blow-molded body, the inner bag having an EVOH layer (ethylene-vinyl alcohol copolymer layer), wherein the ethylene content in the EVOH (ethylene-vinyl alcohol copolymer) contained in the EVOH layer is 32~46 mol.

[0109] The present invention is characterized by providing an EVOH layer in the inner bag of a container body formed by biaxially extended blow molding, the EVOH layer containing EVOH having a high ethylene content of 32-46 mol%. Generally, the higher the ethylene content of the EVOH, the greater the flexibility. Therefore, according to the present invention, it is possible to suppress the deterioration of the pull-out properties of the inner bag and improve the air barrier properties of the inner bag.

[0110] The following examples illustrate various embodiments of the present invention. These embodiments can be combined with each other.

[0111] Preferably, in the described double container, the double container has a mouth mounting member installed at the mouth of the container body, the inner bag has a protrusion protruding from the opening end of the outer shell, and the mouth mounting member engages with the protrusion.

[0112] Preferably, in the described double container, the inner bag is a single-layer structure of the EVOH layer. Attached Figure Description

[0113] Figure 1 This is a front view of the double container 1 according to the first embodiment of the present invention (first to third views, and fifth and sixth views), showing the mouth mounting member 8 separated from the container body 2. The dashed lines in the figure represent the boundary lines of the curvature changes of the surfaces constituting the surface shape. The same applies to the other figures.

[0114] Figure 2A for Figure 1 AA section view, Figure 2B for Figure 2A End view of the BB section in the image. Figure 2C for Figure 2B A magnified view of region C in the image. Figure 2D for Figure 2A End view of the DD section in the image.

[0115] Figure 3A for Figure 2A EE section view, Figure 3B for Figure 3A The exploded diagram. Figure 3C For variations of the first embodiment Figure 3A Corresponding sectional views, Figure 3D for Figure 3C The exploded diagram. Figure 3E For comparison examples and Figure 3A Corresponding sectional views, Figure 3F for Figure 3E The exploded diagram.

[0116] Figure 4A for Figure 1 A magnified stereoscopic view of the area near the mouth (5). Figure 4B for Figure 4A A magnified view of region B in the image.

[0117] Figure 5A A perspective view showing a portion of the mouth-mounting component 8 removed. Figure 5B This is a perspective view of the mouth-mounted component 8 when viewed from a lower angle.

[0118] Figure 6A The front view shows the mouth-mounted component 8 installed on the container body 2. Figure 6B for Figure 6A BB section view in the middle.

[0119] Figure 7A for Figure 1 BB section view in Figure 7B This is a front view of the inner bag 4 near the bottom of the container body 2. Figure 7C for Figure 7B CC section view in the image.

[0120] Figure 8A This is a perspective view of the area near the bottom of the main body 2 of the container, viewed from a lower angle. Figure 8B From Figure 8A A three-dimensional view of the inner bag 4 with the outer shell 3 removed.

[0121] Figure 9A This is a perspective view of the area near the bottom of container body 2 when viewed from an oblique, upper side. Figure 9B From Figure 9A A three-dimensional view of the inner bag 4 with the outer shell 3 removed.

[0122] Figure 10 A perspective view showing the inner preform 14 and the outer preform 13 separated.

[0123] Figure 11A This is the front view of the inner preform 14. Figures 11B-11C They are respectively Figure 11A BB section view and CC section view in the middle. Figure 11D for Figure 11A Enlarged view of the DD section in the image. Figure 11E This is a perspective view of the inner preform 14 viewed from an obliquely upward angle.

[0124] Figure 12A A perspective view showing the intermediate state of the outer preform 13 covering the inner preform 14. Figure 12B for Figure 12A A magnified view of region B in the image. Figure 12C In order to be in Figure 12A End view of the cross-section at the center of the protrusion 14f and the center of the inner preform 14. Figure 12D for Figure 12C An enlarged view of region D in the image.

[0125] Figure 13 A perspective view of a preform 15 formed by covering an inner preform 14 with an outer preform 13.

[0126] Figure 14 In the second embodiment of the present invention (third viewpoint), after only the outer shell 3 is removed from the container body 2, and... Figure 3A The corresponding 3D diagram.

[0127] Figure 15 The container body 2 of the double container 1, which can be manufactured by a method for manufacturing a double container according to an embodiment of the present invention (fourth viewpoint), is shown.

[0128] Figure 16 A perspective view showing the inner preform 14 and the outer preform 13 separated.

[0129] Figure 17A This is a perspective view of a preform 15 formed by an outer preform 13 covering an inner preform 14. Figure 17B To observe from other angles Figure 17A A three-dimensional image of the time.

[0130] Figure 18A To illustrate the graphs showing the results of differential scanning calorimetry measurements of the propylene-ethylene random copolymer in Example 1, Figure 18B A graph showing the results of differential scanning calorimetry measurements of amorphous PET in Example 1.

[0131] Figure 19 This is a cross-sectional view showing the state in which the preform 15 is mounted on the mouth support mold 51 and brought close to the heater 61.

[0132] Figure 20 To show from Figure 19 The view shows the state after the mouth support mold 51, on which the preform 15 is mounted, has been moved to a position between the forming molds 53 and 54.

[0133] Figure 21 To show from Figure 20 A cross-sectional view of the state after the molding molds 53 and 54 are closed and the bottom support mold 52 supports the bottom 13c of the external preform 13.

[0134] Figure 22 To show from Figure 21 The view shows the state after the support rod 25 is extended and the bottom support mold 52 is retracted, causing the preform 15 to extend longitudinally.

[0135] Figure 23 This is a front view of the container body 2 of a dual container 1 according to one embodiment of the present invention (seventh viewpoint).

[0136] Figure 24 for Figure 23 An exploded perspective view of the area near the opening 5 of the container body 2.

[0137] Figure 25A For crossing Figure 23 A cross-sectional view of the center of the opening 5 of the container body 2, parallel to the paper. Figure 25B for Figure 25AA magnified view of region B in the image. Figure 25C Showing from Figure 25A The state after slightly lifting the inner bag 4. Figure 25D for Figure 25C An enlarged view of region D in the image. Figure 25E Showing from Figure 25C The state is the state after the outer shell is expanded in diameter 3.

[0138] Figure 26 This is a perspective view of the inner preform 14 and the outer preform 13.

[0139] Figure 27A This is a front view showing the inner preform 14 inserted into the outer preform 13. Figure 27B For crossing Figure 27A A cross-sectional view of the surface of the opening 15a that is parallel to the central axis and the paper.

[0140] Figure 28A This is a perspective view of the double container 1 according to the first embodiment of the present invention (eighth and tenth perspectives), showing the mouth mounting member 8 separated from the container body 2. Figure 28B for Figure 28A A magnified view of region B in the image.

[0141] Figure 29 A cross-sectional view of the center axis C of the opening 5 through the container body 2 and the center of the two recesses 3f.

[0142] Figure 30A for Figure 29 A magnified view of region A in the image. Figure 30B for Figure 29 A magnified view of region B in the image.

[0143] Figures 31A-31C They are respectively Figure 30A End view of face A~C.

[0144] Figures 32A-32F These are the front view, top view, bottom view, right side view, left side view, and rear view of the container body 2.

[0145] Figure 33A A perspective view showing a portion of the mouth-mounting component 8 removed. Figure 33B This is a perspective view of the mouth-mounted component 8 when viewed from a lower angle.

[0146] Figure 34 A front view of the mouth-mounted component 8 installed on the container body 2.

[0147] Figures 35A-35B They are respectively Figure 34 End view of face A~B in the middle.

[0148] Figure 36 A perspective view showing the inner preform 14 and the outer preform 13 separated.

[0149] Figure 37 This is a perspective view of the inner preform 14 viewed from an obliquely upward angle.

[0150] Figure 38 A perspective view of a preform 15 formed by covering an inner preform 14 with an outer preform 13.

[0151] Figure 39 This is a perspective view of the double container 1 according to the first embodiment of the present invention (ninth viewpoint), showing the state in which the mouth mounting member 8 is separated from the container body 2.

[0152] Figure 40 for Figure 39 A magnified view of region B in the image.

[0153] Figure 41 This is a cross-sectional view that passes through the central axis of the opening 5 of the container body 2 and is perpendicular to the opening surface 5c1.

[0154] Figure 42 This is an exploded perspective view of container body 2.

[0155] Figure 43 This is a three-dimensional view of the outer shell 3.

[0156] Figure 44A A perspective view showing a portion of the mouth-mounting component 8 removed. Figure 44B This is a perspective view of the mouth-mounted component 8 when viewed from a lower angle.

[0157] Figure 45 A front view of the mouth-mounted component 8 installed on the container body 2.

[0158] Figures 46A-46B They are respectively Figure 45 End view of face A~B in the middle.

[0159] Figure 47 A perspective view showing the inner preform 14 and the outer preform 13 separated.

[0160] Figure 48 A perspective view of a preform 15 formed by covering an inner preform 14 with an outer preform 13. Detailed Implementation

[0161] The following describes embodiments of the present invention. The various features shown in the embodiments described below can be combined with each other. Furthermore, each feature can independently constitute an invention. In the following embodiments, regarding each viewpoint, the matters specified in the means for solving the problem are essential structures for each viewpoint, while other structures are arbitrary. Moreover, features associated with different viewpoints can be combined with each other without violating their spirit.

[0162] Figures 1-13 This is related to the first, second, fifth, and sixth viewpoints of the present invention. Figures 1-14 This is related to the third point of view of the present invention. Figures 15-22 This is related to the fourth point of view of the present invention. Figure 23 Figure 27 is related to the seventh aspect of the present invention. Figure 28 Figure 38 This is related to the eighth and tenth points of view of the present invention. Figures 39-48 This is related to the ninth point of view of the present invention.

[0163] (First viewpoint to third viewpoint, fifth viewpoint and sixth viewpoint)

[0164] 1. The first implementation method common to the first to third, fifth, and sixth viewpoints.

[0165] 1-1. Structure of Double Container 1

[0166] <Basic Structure>

[0167] like Figure 1 As shown, the dual container 1 of the first embodiment of the present invention has a container body 2 and an opening mounting member 8.

[0168] like Figure 1 As shown, the container body 2 has a mouth 5, a body 6, and a bottom 7. The mouth 5 is a cylindrical (preferably cylindrical) portion with an open end 5c. The mouth 5 has a locking portion 5a for mounting a mouth mounting member 8 such as a cap or pump. In the case of a threaded mouth mounting member 8, the locking portion 5a is an externally threaded portion 5a1; in the case of a capped mouth mounting member 8, the locking portion 5a is an annular protrusion protruding in the circumferential direction. The mouth mounting member 8 may have a check valve (not shown). In this case, the contents can be discharged through the mouth mounting member 8, but external gas will not flow into the container body 2. A flange 5b is provided in the mouth 5. When the mouth mounting member 8 is mounted in the mouth 5, the flange 5b can be used to support the mouth 5.

[0169] The body 6 is disposed adjacent to the opening 5 on the side further away from the opening end 5c than the opening 5. The outer diameter of the body 6 (in this specification, "outer diameter" means the diameter of the circumscribed circle when the cross-section is not circular) is larger than that of the opening 5. The body 6 is cylindrical, and the bottom 7 is provided at the lower end of the body 6, closing the lower end of the body 6. The body 6 has a shoulder 6b, whose outer diameter increases as it moves further away from the opening 5. In addition, the body 6 has a body body 6c with a substantially constant outer diameter on the side of the bottom 7 closer to the shoulder 6b.

[0170] The diameter of the opening 5, excluding the engaging portion 5a, is, for example, 20 to 40 mm, preferably 25 to 35 mm. Specifically, it is, for example, 20, 25, 30, 35, or 40 mm, or any two of the values ​​exemplified herein. The length of the opening 5 is, for example, 15 to 35 mm. Specifically, it is, for example, 15, 20, 25, 30, or 35 mm, or any two of the values ​​exemplified herein.

[0171] like Figures 2A-2D As shown, the container body 2 has an inner bag 4 and an outer shell 3 arranged to cover the inner bag 4. The portion of the inner bag 4, except for the protrusion 4c described later, is housed within the outer shell 3. In the following description, the portions of the inner bag 4 corresponding to the opening 5, body 6, and bottom 7 of the container body 2 will be referred to as the opening 5, body 6, and bottom 7 of the inner bag 4, respectively. The same applies to the outer shell 3.

[0172] The wall thickness of the outer shell 3 at the center of the container body 2 in the height direction is, for example, 0.3~0.8 mm, preferably 0.4~0.5 mm. Specifically, the wall thickness is, for example, 0.3, 0.4, 0.5, 0.6, 0.7, or 0.8 mm, or may be within any two values ​​exemplified herein. The wall thickness of the inner bag 4 at the center of the container body 2 in the height direction is, for example, 0.10~0.25 mm, preferably 0.15~0.20 mm. Specifically, the wall thickness is, for example, 0.10, 0.15, 0.20, or 0.25 mm, or may be within any two values ​​exemplified herein. The greater the wall thickness of the inner bag 4, the easier it is to pull out the inner bag 4; therefore, the application of this invention is significant.

[0173] When a check valve is provided in the opening mounting member 8, the inner bag 4 contracts as its contents are discharged. When a check valve is not provided in the opening mounting member 8, the inner bag 4 does not contract after its contents are discharged, making it difficult to pull the inner bag 4 through the opening 5 of the outer shell 3. This invention, by twisting the inner bag 4 and reducing its diameter, makes it easy to pull the inner bag 4 through the opening 5 of the outer shell. Therefore, the application of this invention is particularly significant when a check valve is not provided in the opening mounting member 8. However, even when a check valve is provided in the opening mounting member 8, there is a possibility that the inner bag 4 does not properly reduce its diameter when it contracts. Therefore, the application of this invention is significant even when a check valve is provided in the opening mounting member 8.

[0174] An external gas inlet 16 is provided on the body 6 or the bottom 7. The external gas inlet 16 is a through hole penetrating the outer shell 3, allowing external gas to be introduced into the intermediate space between the outer shell 3 and the inner bag 4. On the other hand, when no check valve is provided on the opening mounting member 8, the external gas inlet 16 can be omitted because the inner bag 4 does not shrink. When the double container 1 is a so-called squeeze container with a structure that discharges contents by compressing the outer shell 3, it is preferable to provide a check valve that controls the air intake and exhaust through the external gas inlet 16. The check valve is preferably configured such that the external gas inlet 16 is closed when the outer shell 3 is compressed and open when the compressive force is removed. In this case, when a compressive force is applied to the outer shell 3, the compressive force is easily applied to the inner bag 4, and after the contents are discharged, external gas is quickly introduced into the intermediate space, and the shape of the outer shell 3 quickly recovers.

[0175] When a check valve is provided at the external gas inlet 16, it is preferable that the external gas inlet 16 is disposed within the recess 6d of the body 6. In this case, interference between the check valve and the shrink film can be avoided when the body 6 is covered by the shrink film. Furthermore, it is preferable to provide a groove 6e extending from the recess 6d toward the opening 5. The groove 6e extends to a position not covered by the shrink film. This prevents the recess 6d from being sealed by the shrink film.

[0176] <The uneven shape of the inner surface of the mouth 5>

[0177] like Figures 2A-2DAs shown, preferably, at least one of the inner surfaces of the opening 5 and the body 6 adjacent to the opening 5 is provided with a concave-convex shape 9, which is a shape in which concave strips 9a and convex strips 9b alternate in the circumferential direction of the opening 5. The concave-convex shape 9 is provided on the inner surface of the inner bag 4. The number of concave strips 9a is, for example, 4 to 30, preferably 10 to 20. The concave strips 9a and convex strips 9b preferably extend in a manner that is not parallel to the circumferential direction of the opening 5. The extension direction of the concave strips 9a and convex strips 9b relative to the axial direction of the opening 5 is preferably 0 to 60 degrees, preferably 0 to 30 degrees. Specifically, this angle is, for example, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 degrees, or may be within the range of any two values ​​exemplified herein. The concave-convex shape 9 can be provided only in the opening 5, or it can be provided in the body 6 at a position adjacent to the opening 5, but it is preferred to be provided across the opening 5 and the body 6. Compared with other parts of the opening 5 of the inner bag 4, the concave-convex shape 9 can be formed by reducing the wall thickness of the concave strip 9a, increasing the wall thickness of the convex strip 9b, or by reducing the wall thickness of the concave strip 9a and increasing the wall thickness of the convex strip 9b.

[0178] The wall thickness at the convex strip 9b is greater than that at the concave strip 9a. Therefore, when the torsion applied at the opening 5 is transmitted to the body 6, the convex strip 9b transmits the force more easily than the concave strip 9a. Consequently, the convex strip 9b rotates earlier than the concave strip 9a. As a result, the inner bag 4 is easily folded into a pleated shape by forming creases on the concave strip 9a and its extension. Therefore, by providing the convex and concave shapes 9, the body 6 is folded into a pleated shape, resulting in a rapid reduction in the diameter of the body 6. Furthermore, it is preferable not to provide convex and concave shapes on the outer surface of the inner bag 4. If convex and concave shapes are provided on the outer surface of the inner bag 4, the inner bag 4 and the outer shell 3 will engage in the rotational direction of the inner bag 4, making it difficult for the inner bag 4 to rotate relative to the outer shell 3.

[0179] If we define the wall thickness of the inner bag 4 at the protrusion 9b of the opening 5 (radius of the circumscribed circle of the inner bag 4 - radius of the inscribed circle passing through the vertex of the protrusion 9b) as T, and the depth of the concave slat 9a (radius of the inscribed circle passing through the bottom of the concave slat 9a - radius of the inscribed circle passing through the vertex of the protrusion 9b) as D, then the maximum value of D / T is, for example, 0.2 to 0.8, preferably 0.3 to 0.5. Specifically, this value is, for example, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, or 0.8, or it can be within the range of any two values ​​exemplified herein. The wall thickness of the inner bag 4 at the opening 5, excluding the convex / concave shape 9, is, for example, 1 to 2 mm, specifically, for example, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2.0 mm, or may be within the range of any two values ​​exemplified herein. The depth of the recess 9a at the location with the greatest depth is, for example, 0.3 to 1.0 mm, specifically, for example, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0 mm, or may be within the range of any two values ​​exemplified herein.

[0180] The distance from the opening end 5c of the mouth 5 to the upper end of the concave-convex shape 9 is, for example, 0 to 30 mm, specifically, for example, 0, 5, 10, 15, 20, 25, or 30 mm, or it can be within any two values ​​exemplified herein. The distance from the upper end to the lower end of the concave-convex shape 9 is, for example, 10 to 40 mm, specifically, for example, 10, 15, 20, 25, 30, 35, or 40 mm, or it can be within any two values ​​exemplified herein.

[0181] <Structure of the bottom 7>

[0182] like Figures 7A to 9B As shown, a protrusion 4e is provided at the bottom 7 of the inner bag 4. An annular protrusion 3b is provided at the bottom 7 of the outer shell 3, and a through hole 3c is provided in the area inside the annular protrusion 3b. The inner bag 4 is positioned relative to the outer shell 3 by inserting the protrusion 4e into the through hole 3c. The annular protrusion 3b and its inner area do not extend substantially during biaxial stretch blow molding; therefore, the wall thickness of both the outer shell 3 and the inner bag 4 increases. The annular protrusion 3b can be omitted.

[0183] If the outer diameter of the annular protrusion 3b is set as D1, and the inner diameter of the opening 5 of the outer shell 3 is set as D2, then D1 / D2 is preferably 0.9 or less, more preferably 0.6 or less. Since the wall thickness of the inner bag 4 increases due to the increased size of the annular protrusion 3b and its inner side, the smaller D1 / D2 is, the easier it is for the bottom 7 of the inner bag 4 to narrow. D1 / D2 is, for example, 0.1 to 0.9, specifically, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or it can be within the range of any two values ​​exemplified herein, or below any value.

[0184] A bottom recessed area 7a and a peripheral area 7b surrounding the bottom recessed area 7a are provided at the bottom 7 of the container body 2 (i.e., the respective bottom 7 of the inner bag 4 and the outer shell 3). The bottom recessed area 7a is the area recessed inward from the bottom 7 towards the container body 2. The peripheral area 7b serves as the ground surface of the container body 2. Figure 7A As shown, on the peripheral surface 7a1 of the bottom concave region 7a, the wall thickness of the inner bag 4 and the outer shell 3 gradually decreases as they approach the peripheral region 7b. The peripheral surface 7a1 becomes an inclined surface that slopes away from the center of the bottom 7 towards the peripheral region 7b. In other words, the peripheral surface 7a1 forms part of a cone that contracts towards the bottom surface 7a2 of the bottom concave region 7a. The bottom surface 7a2 of the bottom concave region 7a is generally flat. Therefore, the bottom concave region 7a becomes approximately frustum-shaped.

[0185] The bottom surface 7a2 of the concave region 7a is difficult to extend during biaxial blow molding, and the wall thickness tends to increase. Therefore, the smaller the diameter D3 of the bottom surface 7a2 (in other words, the diameter of the area surrounded by the boundary line between the bottom surface 7a2 and the peripheral surface 7a1), the easier it is for the bottom 7 of the inner bag 4 to shrink in diameter. D3 / D2 is preferably 0.9 or less, more preferably 0.6 or less. D3 / D2 is, for example, 0.1 to 0.9, specifically, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or it can be within the range of any two values ​​exemplified herein or below any value.

[0186] <Alternating wall thickness shape 10 set at the bottom 7>

[0187] like Figures 7A to 9B As shown, it is preferable to provide an alternating wall thickness shape 10 at the bottom 7 of the inner bag 4. The alternating wall thickness shape 10 is a shape in which thin-walled portions 10a and thick-walled portions 10b with a wall thickness greater than that of the thin-walled portions 10a alternate in the circumferential direction of the inner bag 4. By providing an alternating wall thickness shape 10 at the bottom 7, when the inner bag 4 is twisted, the thin-walled portions 10a bend, thereby deforming the bottom 7 into a corrugated shape, making the bottom 7 easier to reduce in diameter.

[0188] like Figure 7CAs shown, the wall thickness of the circumferential surface 7a1 is greater than that of the side surface 4d of the inner bag 4 near the bottom 7. Therefore, it is particularly important to provide an alternating wall thickness shape 10 on the circumferential surface 7a1 to facilitate the reduction of the diameter of the bottom 7. Furthermore, the peripheral region 7b is more difficult to deform than the side surface 4d of the inner bag 4 near the bottom 7. Therefore, it is particularly important to provide an alternating wall thickness shape 10 on the peripheral region 7b. Therefore, it is preferable that the alternating wall thickness shape 10 is provided on at least one of the circumferential surface 7a1 of the bottom concave region 7a and the peripheral region 7b, and more preferably, it is provided to span across the circumferential surface 7a1 and the peripheral region 7b. It is also preferable that it spans across the peripheral region 7b and the side surface 4d of the inner bag 4. By providing the alternating wall thickness shape 10 in this way, the bottom 7 becomes easier to reduce in diameter.

[0189] like Figure 8B As shown, the thin-walled portion 10a and the thick-walled portion 10b are preferably arranged to extend radially from the center of the bottom 7. In addition, the number of thin-walled portions 10a is, for example, 4 to 30, preferably 10 to 20.

[0190] The thin-walled portion 10a can be formed by providing recessed strips 11 on one or both of the inner and outer surfaces of the inner bag 4. The recessed strips 11 on the inner surface and the recessed strips 11 on the outer surface of the inner bag 4 face each other. The portion between two adjacent recessed strips 11 is called the thick-walled portion 10b.

[0191] In a cross-section perpendicular to the height direction of the inner bag 4 ( Figure 7C In such a cross-section, the wall thickness of the inner bag 4 at the thin-walled portion 10a is set as T1, and the wall thickness of the inner bag 4 at the thick-walled portion 10b is set as T2. The minimum value of T1 / T2 is preferably 0.8 or less. The minimum value of T1 / T2 refers to the minimum value calculated at each height position by moving the cross-section along the height direction of the inner bag 4. The smaller T1 / T2 is, the smaller the thickness of the thin-walled portion 10a becomes compared to the thick-walled portion 10b, and the more easily the bottom 7 deforms into a corrugated shape. This value is preferably 0.1 or more. If this value is too small, the thickness at the thin-walled portion 10a becomes too small, making it easier to generate pinholes. This value is, for example, 0.1 to 0.8, specifically, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or it can be within the range of any two values ​​exemplified here.

[0192] <The engaging structure between the mouth mounting component 8 and the inner bag 4, and the engaging structure between the inner bag 4 and the outer shell 3 at the mouth 5>

[0193] The preferred mouth mounting member 8 is configured to be mounted on the mouth 5, and the inner bag 4 is configured to rotate with the rotation of the mouth mounting member 8 (in this case, relative rotation with respect to the outer shell 3). According to this structure, the inner bag 4 can be twisted by rotating the mouth mounting member 8. Since the outer diameter of the body 6 of the container body 2 is larger than that of the mouth 5, it is difficult to pull the inner bag 4 through the mouth 5 of the outer shell 3 simply by pulling it. However, by twisting the inner bag 4 and reducing the diameter of its body 6, the body 6 of the inner bag 4 easily passes through the mouth 5 of the outer shell 3, and the inner bag 4 can be easily pulled out of the outer shell 3.

[0194] The following describes in more detail the engagement structure between the mouth mounting component 8 and the inner bag 4.

[0195] like Figures 2A-2D as well as Figures 4A-4B As shown, the inner bag 4 has a protrusion 4c that protrudes from the opening end 3a of the outer shell 3. The protrusion 4c has a protruding cylinder 4c1, a locking protrusion 4c2, a locking flange 4c3, and an abutting flange 4c4.

[0196] The engaging protrusion 4c2 protrudes radially outward from the circumferential surface of the protruding cylinder 4c1. The engaging flange 4c3 is an annular portion located further away from the opening end 3a than the engaging protrusion 4c2 and with a larger diameter than the protruding cylinder 4c1. The abutting flange 4c4 is an annular portion located at an abutment against the opening end 3a and with a larger diameter than the protruding cylinder 4c1. By abutting the opening end 3a with the abutting flange 4c4, the inner bag 4 is prevented from falling into the outer shell 3. Alternatively, the abutting flange 4c4 may be omitted, and the engaging protrusion 4c2 may abut against the opening end 3a, thereby preventing the inner bag 4 from falling into the outer shell 3.

[0197] like Figures 4A to 6B As shown, the mouth mounting component 8 has an outer cylinder 8a, an intermediate cylinder 8b, an inner cylinder 8c, a locking part 8d, a claw part 8e, a top plate 8f, and a nozzle 8g.

[0198] An engaging portion 8d is provided on the inner surface of the outer cylinder 8a. The engaging portion 8d engages with the engaging portion 5a of the opening 5. By engaging the engaging portion 8d with the engaging portion 5a, the opening mounting member 8 is installed on the opening 5.

[0199] The intermediate cylinder 8b has a smaller diameter than the outer cylinder 8a and is positioned above the outer cylinder 8a. The inner cylinder 8c is a so-called inner ring, with a smaller diameter than the intermediate cylinder 8b, and is positioned inside both the outer cylinder 8a and the intermediate cylinder 8b. The upper surface of the intermediate cylinder 8b is covered by a top plate 8f. A nozzle 8g is provided on the top plate 8f.

[0200] A claw portion 8e is provided on the inner surface of the intermediate cylinder 8b. Multiple claw portions 8e are arranged separately in the circumferential direction (eight in this embodiment). The number of claw portions 8e is, for example, 1 to 20, preferably 4 to 12. Each claw portion 8e has an upper surface 8e1 and a lower inclined surface 8e2. A through hole 8h is provided on the top plate 8f at a position facing the claw portions 8e.

[0201] The opening mounting member 8 of this shape can be manufactured using a split mold that opens and closes in the vertical direction. The through hole 8h and the upper surface 8e1 can be formed using the protrusion of the upper mold, so the claw 8e can be formed without forcibly pulling out the lower mold. Therefore, it is not necessary to set the protrusion of the claw 8e to a protrusion that can be forcibly pulled out, but can be set to a protrusion suitable for engaging with the inner bag 4 (e.g., 1 mm or more).

[0202] In this embodiment, the engaging portion 5a is an externally threaded portion 5a1, and the engaging portion 8d is an internally threaded portion 8d1 that can engage with the externally threaded portion 5a1. Therefore, by rotating the mouth-mounting member 8 relative to the mouth 5 in the fastening direction (usually clockwise when viewed from above) (hereinafter, the relative rotation relative to the mouth 5 will be simply referred to as "rotation"), the mouth-mounting member 8 can be mounted on the mouth 5. If the mouth-mounting member 8 is rotated in the fastening direction, then Figure 5B The outer circumferential surface of the inner cylinder 8c is tightly pressed against the inner circumferential surface of the inner bag 4, and the internal thread 8d1 is screwed into the external thread 5a1. At this time, if the opening 5 of the inner bag 4 and the opening mounting member 8 rotate together due to friction between the outer circumferential surface of the inner cylinder 8c and the inner circumferential surface of the inner bag 4, the inner bag 4 will be twisted. If the inner bag 4 is filled with contents before the opening mounting member 8 is installed, the contents of the inner bag 4 will overflow if it is twisted. To prevent this problem, the inner bag 4 should be tightly fitted to the outer shell 3 in the opening 5 without rotating relative to the outer shell 3. However, if only a tight fit is made, a new problem arises where it becomes difficult to pull the inner bag 4 out of the outer shell 3.

[0203] Therefore, in this embodiment, a structure is adopted in which the first resistance to relative rotation of the inner bag 4 relative to the outer shell 3 in one direction is greater than the second resistance to relative rotation in the other direction. For example, when the external thread 5a1 is a right-hand thread, one direction and the other direction are the clockwise and counterclockwise directions when viewed from the top of the container body 2, respectively. In other words, one direction is the tightening direction of the mouth mounting member 8, and the other direction is the loosening direction of the mouth mounting member 8. According to this structure, when the mouth mounting member 8 is installed, it is difficult for the inner bag 4 to rotate relative to the outer shell 3, thus suppressing the problem of the inner bag 4 being twisted when the mouth mounting member 8 is installed. In addition, since the second resistance to relative rotation in the other direction is relatively small, when separating the inner bag 4 from the outer shell 3 after use, by rotating the mouth 5 of the inner bag 4 relative to the outer shell 3 in the other direction, the inner bag 4 can be easily twisted and its diameter reduced, thereby easily pulling the inner bag 4 out of the outer shell 3.

[0204] Specifically, the inner bag 4 and the outer shell 3 engage with each other at the opening 5, and this engagement creates a first resistance greater than a second resistance. More specifically, as... Figure 2C as well as Figure 4B As shown, the interlocking mechanism is the engagement of a protrusion 4f on the outer peripheral surface of the inner bag 4 and a recess 3f on the inner peripheral surface of the outer shell 3. Figure 2C As shown, a conical surface 4f1 for reducing the second resistance is provided on the right side (loosening direction side) of the protrusion 4f. On the other hand, no conical surface is provided on the left side (fastening direction side) of the protrusion 4f. Therefore, in the opening 5, the resistance (first resistance) for rotating the inner bag 4 relative to the outer shell 3 in the fastening direction is greater than the resistance (second resistance) for rotating in the loosening direction. In this embodiment, two groups of protrusions 4f and recesses 3f can be provided at 180-degree intervals, but the number of groups of protrusions 4f and recesses 3f can be one or more.

[0205] Alternatively, a conical surface 4f1 can be provided instead, or a conical surface can be provided in the recess 3f while providing the conical surface 4f1, thereby reducing the second resistance. Furthermore, the interlocking can be between a recess on the outer periphery of the inner bag 4 and a protrusion on the inner periphery of the outer shell 3. Additionally, the recess 3f is formed by a through hole penetrating the outer shell 3, but the recess 3f only needs to be able to engage with the protrusion 4f; it does not necessarily need to penetrate the outer shell 3.

[0206] If the mouth-mounting member 8 is rotated further in the tightening direction, the internal thread 8d1 engages with the external thread 5a1, while the claw 8e gradually approaches the protrusion 4c, and at a certain point, the lower inclined surface 8e2 abuts against the engaging flange 4c3. In this state, if the mouth-mounting member 8 is rotated further in the tightening direction, the claw 8e passes over the engaging flange 4c3, becoming... Figure 6A and Figure 6B The state shown. In this state, the claw portion 8e is positioned between the engaging flange 4c3 and the abutting flange 4c4. The engaging flange 4c3 is accommodated in the gap between the claw portion 8e and the top plate 8f. Figure 6B As shown, the protruding cylinder 4c1 is positioned between the claw portion 8e and the inner cylinder 8c. At this point in time, before the external thread portion 5a1 and the internal thread portion 8d1 are fully tightened, the claw portion 8e is guided by the circumferentially inclined surface 4c5 of the engaging protrusion 4c2 and passes over the engaging protrusion 4c2, thereby allowing the mouth mounting member 8 to rotate further in the tightening direction. After the external thread portion 5a1 and the internal thread portion 8d1 are fully tightened, the mouth mounting member 8 cannot rotate in the tightening direction and cannot move axially in the mouth portion 5.

[0207] In this state, the engaging protrusion 4c2 engages with the claw portion 8e of the mouth mounting member 8 in the rotational direction of the mouth mounting member 8, and the engaging flange 4c3 engages with the claw portion 8e of the mouth mounting member 8 in the axial direction of the mouth 5. That is, the claw portion 8e engages with the engaging protrusion 4c2 and the engaging flange 4c3.

[0208] Therefore, after the contents of the inner bag 4 are used up, if the opening mounting member 8 is rotated in the loosening direction (usually counterclockwise when viewed from above), the inner bag 4 will rotate along with the opening mounting member 8. As a result, the inner bag 4 is twisted and its diameter is reduced.

[0209] If the opening mounting member 8 is rotated further in the loosening direction and the engagement between the internal thread 8d1 and the external thread 5a1 is released, the opening mounting member 8 can move away from the opening end 3a (i.e., in the axial direction of the opening 5). The engaging flange 4c3 engages with the opening mounting member 8 in the axial direction of the opening 5. Therefore, if the opening mounting member 8 is moved in the axial direction of the opening 5, the inner bag 4 also moves with the opening mounting member 8, and the inner bag 4 is pulled out from the outer shell 3.

[0210] As described above, according to the structure of this embodiment, the inner bag 4 can be pulled out from the outer shell 3 simply by rotating the mouth mounting member 8 in the loosening direction. Therefore, the inner bag 4 can be smoothly separated from the outer shell 3 with simple operation.

[0211] <The irregular shape on the outer surface of the inner pocket 4 or the inner surface of the outer shell in shoulder 6b>

[0212] The shoulder portion 6b is the part whose outer diameter increases as it leaves the opening 5. Therefore, when the inner bag 4 is pulled out of the outer shell 3, the outer surface of the inner bag 4 is pressed particularly strongly against the inner surface of the outer shell 3 within the shoulder portion 6b. Thus, by reducing the frictional resistance between the inner bag 4 and the outer shell 3 at the shoulder portion 6b, the force required to pull out the inner bag 4 can be effectively reduced. Therefore, in this embodiment, as... Figures 3A-3B As shown, in the shoulder 6b of the container body 2, at least one of the outer surface of the inner bag 4 and the inner surface of the outer shell 3 is provided with a concave-convex shape 35 to reduce the contact area between the outer surface of the inner bag 4 and the inner surface of the outer shell 3.

[0213] The concave-convex shape 35 can be provided only on the outer surface of the inner bag 4, only on the inner surface of the outer shell 3, or on both the outer surface of the inner bag 4 and the inner surface of the outer shell 3. In this embodiment, as... Figures 3A-3B As shown, the outer surface of the inner bag 4 has a raised / lower shape 34, while the inner surface of the outer shell 3 does not have a raised / lower shape. In this case, the outer surface of the inner bag 4 contacts the inner surface of the outer shell 3 at the protrusions 34a of the raised / lower shape 34, but not at the recesses 34b, thus reducing the contact area. Figures 3C-3D As shown in the modified example, a non-complementary convex-concave shape 33 may also be provided on the inner surface of the outer casing 3. In this case, the contact area between the outer surface of the inner bag 4 and the inner surface of the outer casing 3 is also reduced.

[0214] On the other hand, such as Figures 3E-3F As shown in the comparative example, if complementary convex and concave shapes 34 and 33 are provided on the outer surface of the inner bag 4 and the inner surface of the outer shell 3, then the protrusion 34a of the convex and concave shape 34 of the inner bag 4 enters the concave portion 33b of the convex and concave shape 33 of the outer shell 3, and the concave portion 34b of the convex and concave shape 34 of the inner bag 4 enters the protrusion 33a of the convex and concave shape 33 of the outer shell 3. Therefore, the contact area between the outer surface of the inner bag 4 and the inner surface of the outer shell 3 actually increases. This type of convex and concave shape is not a "convex and concave shape 35 that reduces the contact area between the outer surface of the inner bag 4 and the inner surface of the outer shell 3".

[0215] The ratio of the depth of the recess 34b, as observed from the highest point of the protrusion 34a of the convex-concave shape 34, to the wall thickness of the inner bag 4 at the highest point is, for example, 0.01 to 0.5, specifically, for example, 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, or 0.5, or it can be within any two values ​​exemplified herein. If this ratio is too small, the reduction effect on frictional resistance will be insufficient; if it is too large, pinholes may easily form in the inner bag 4.

[0216] The convex-concave shape 35 can be a shape in which the convex and concave portions are regularly arranged, or a shape in which the convex and concave portions are irregularly arranged. The inner bag 4 having the convex-concave shape 34 on its outer surface can be formed by biaxial extension blow molding of the inner preform 14 having the convex-concave shape on its outer surface. The outer shell 3 having the convex-concave shape 33 on its inner surface can be formed by biaxial extension blow molding of the outer preform 13 having the convex-concave shape on its inner surface.

[0217] The concave-convex shape 35 can be formed in the area including the shoulder 6b, but is preferably formed in the area including both the shoulder 6b and the bottom 7. This is because even at the bottom 7, the frictional resistance between the outer surface of the inner bag 4 and the inner surface of the outer shell 3 tends to increase.

[0218] Laser marking

[0219] Furthermore, methods for handling the separated inner bag 4 include horizontal recycling, cascade recycling, and heat recycling. However, if there is no indication on the inner bag 4, it is difficult for the user to determine how to handle the separated inner bag 4. For containers that do not separate the outer shell 3 from the inner bag 4, it is easy to imprint the recycling mark on the container by setting a prescribed recycling mark shape on the molding die. On the other hand, as in this embodiment, when the outer shell 3 and the inner bag 4 are separated, it is necessary to attach a recycling mark different from that on the outer shell 3 to the inner bag 4, but it is not possible to use the molding die to imprint the recycling mark only on the inner bag 4. Alternatively, it is also possible to set the recycling mark on the inner preform 14 described later, but when the inner preform 14 is biaxially extended and blow-molded, in addition to the difficulty in correctly controlling which part of the inner preform 14 is extended to what extent, there is also the problem that the recycling mark is also extended and becomes unclear when the inner preform 14 is extended. Therefore, it is difficult to attach a clear recycling mark only on the inner bag 4.

[0220] In this embodiment, such as Figure 1 As shown, an information transmission display 22 is printed on the inner bag 4 by laser irradiation. The printing by laser irradiation is achieved by altering the material (oxidation, peeling, color development, discoloration, etc.) through laser irradiation. Laser irradiation can be performed using a laser marker. A laser marker is a device capable of scanning and irradiating with a laser in at least two dimensions, causing the laser spot to move along a pre-set path, thereby printing a pre-set shape. The laser marker used for printing on the inner bag 4 is preferably a fiber laser marker.

[0221] Since the printing on the inner bag 4 is performed through the outer casing 3, the laser preferably has a wavelength that is difficult for the outer casing 3 to absorb. The laser wavelength is preferably 500-1150 nm, more preferably 950-1150 nm, more preferably 1000-1100 nm, and more preferably 1064 nm. Specifically, this wavelength is, for example, 500, 950, 1000, 1010, 1020, 1030, 1040, 1050, 1060, 1064, 1070, 1080, 1090, 1100, or 1150 nm, or may be within any two of the values ​​exemplified herein. This laser is difficult for PET (Polyethylene terephthalate) to absorb; therefore, when the outer casing 3 is made of PET, printing can be performed through the outer casing 3 onto the inner bag 4.

[0222] However, since the laser is also difficult for polyolefins (e.g., polypropylene, polyethylene) to absorb, it is preferable to prepare the laser marking agent in the inner bag 4. The laser marking agent is a substance that absorbs the laser more easily than the resin constituting the inner bag 4 and / or is more likely to change color due to laser absorption than the resin constituting the inner bag 4. By preparing the laser marking agent in the inner bag 4, it becomes easier to print on the inner bag 4. Specifically, as a laser marking agent, it is preferable to use antimony-doped tin oxide, antimony or its compounds, associative basic dye precursors (2,2-bis{4-[6'-(cyclohexyl-N-methylamino)-3'-methylspiro[phthalyl-3,9'-xanthan]-2'-ylamino]phenyl}propane), phthalide dye precursors, fluorane dye precursors, spiropyran dye precursors, lactam dye precursors, etc. The laser marking agent, for example, as a masterbatch (a resin material containing the laser marking agent at a specified concentration), is preferably in a form suitable for molding and processing, such as granules, particles, or pastes.

[0223] The information delivery display 22 is used to convey information about the processing method of the inner bag 4. It can consist of only patterns, only text, or a combination of both. In one example, the information delivery display 22 consists of a recycling symbol 22a and a message 22b. Figure 1 In the example, recycling label 22a indicates that the inner bag 4 is made of general-purpose plastic, and message 22b indicates that the recommended recycling method is thermal recycling. The information display 22 is printed on the inner bag 4 and therefore remains attached to it after the inner bag 4 is separated from the outer casing 3. Thus, it is easy for the user to determine how to dispose of the inner bag 4.

[0224] Preferably, a gap (air layer) is provided between the inner bag 4 and the outer casing 3 where the information transmission display 22 is printed. When a gap exists between the two, smoke is generated when the information transmission display 22 is printed, and the microparticles contained in the smoke adhere to the inner surface of the outer casing 3 or the outer surface of the inner bag 4. These microparticles function as a lubricant, reducing the resistance when the inner bag 4 is pulled out of the outer casing 3.

[0225] The information display 22 is preferably printed only on the inner pocket 4, but depending on the laser irradiation conditions, it may sometimes be printed on the outer shell 3. In this case, the information display 22 printed on the outer shell 3 is preferably lighter (lower visual visibility) than the information display 22 printed on the inner pocket 4. Furthermore, it is preferable that no raised or recessed shapes are formed on the outer shell 3 due to the printing of the information display 22, and the surface of the outer shell 3 is preferably smooth.

[0226] An information transmission display 23 is provided on the outer casing 3. The information transmission display 23 is used to display information about the processing method of the outer casing 3, and can consist of only patterns, only text, or a combination of both. In this example, the information transmission display 23 consists of a recycling flag 23a and a message 23b. Figure 1 In the example, recycling label 23a indicates that the casing 3 is made of PET, and message 23b indicates that the recommended recycling method is horizontal recycling. The method of attaching the information delivery display 23 is not particularly limited. Adhesive labels or ink printing methods may adversely affect the recyclability of the casing 3. Therefore, it is preferable that the information delivery display 23 is attached by laser irradiation printing.

[0227] When the outer casing 3 is made of PET, the wavelength of the laser is preferably 8.0~12μm, and more preferably 9.0~11μm. Specifically, this wavelength is, for example, 8.0, 8.5, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11.0, 11.5, or 12.0μm, or any two values ​​exemplified here. Laser of such wavelengths is easily absorbed by the outer casing 3, and is therefore suitable for printing information transmission display 23 on the outer casing 3. The laser marking machine used for printing on the outer casing 3 is preferably a CO2 laser marking machine capable of emitting laser of the above wavelengths.

[0228] Information display 23 is preferably printed only on the outer casing 3, but depending on the laser irradiation conditions, it may sometimes also be printed on the inner pocket 4. In this case, the information display 23 printed on the inner pocket 4 is preferably lighter than the information display 23 printed on the outer casing 3 (lower visual visibility). Preferably, information display 23 is configured not to overlap with information display 22.

[0229] Alternatively, a covered area can be provided on the outer casing 3 to obscure the information transmission display 22. The method of providing the covered area is not particularly limited, but methods such as affixing labels or printing with ink can negatively impact the recyclability of the outer casing 3. Therefore, it is preferable to attach the covered area by laser-printed text. In this case, the information transmission display 22 can be visually confirmed for the first time by pulling out the inner bag 4, thus preventing user confusion caused by visually confirming both the information transmission display 22 and the information transmission display 23 on the container body 2 before pulling out the inner bag 4. Furthermore, if the information transmission display 22 is an interesting display such as a lottery, providing a covered area can provide an incentive to pull out the inner bag 4.

[0230] 1-2. Method for manufacturing double container 1

[0231] like Figures 10-13 As shown, the container body 2 can be formed by biaxial stretch blow molding of the heated preform 15. In one example, the preform 15 can be formed by covering the inner preform 14, which becomes the inner bag 4, with the outer preform 13, which becomes the outer shell 3.

[0232] <Structure of inner preform 14, outer preform 13, and preform 15>

[0233] like Figure 10 As shown, the inner preform 14 is a bottomed cylindrical part, having an opening 14a, a body 14b, and a bottom 14c. A protrusion 14d is provided at the open end of the opening 14a. The protrusion 14d does not deform during molding and remains in its original shape as the protrusion 4c. Therefore, the matters described for the protrusion 4c also apply to the protrusion 14d. The bottom 14c is configured to close the lower end of the body 14b. A locating pin 14c1 is provided at the bottom 14c.

[0234] like Figures 11A-11E As shown, an uneven shape 19 is provided on the inner surface of the inner preform 14. The uneven shape 19 either remains in its original shape or is extended during molding to become the uneven shape 9 of the container body 2. The description of the uneven shape 9 also applies to the uneven shape 19 as long as it does not deviate from its main idea.

[0235] like Figures 10-11EAs shown, an alternating wall thickness shape 20 is provided near the bottom 14c of the inner preform 14. The alternating wall thickness shape 20 is a shape in which thin-walled portions 20a and thick-walled portions 20b with a wall thickness greater than that of the thin-walled portions 20a alternate in the circumferential direction. The alternating wall thickness shape 20 is extended during biaxial stretch blow molding and becomes an alternating wall thickness shape 10. The number of thin-walled portions 20a is, for example, 4 to 30, preferably 10 to 20. Preferably, the thin-walled portions 20a are provided in a direction along the length direction of the inner preform 14.

[0236] The thin-walled portion 20a can be formed by providing a recess 21 on one or both of the inner and outer surfaces of the inner preform 14. If the recess 21 is provided on the inner surface of the inner preform 14, a recess 11 is formed on the inner surface of the inner bag 4 after molding. If the recess 21 is provided on the outer surface of the inner preform 14, a recess 11 is formed on the outer surface of the inner bag 4 after molding, and a recess 11 is also formed on the inner surface of the inner bag 4 at a position opposite to the recess 11 on the outer surface. This is because the resin at the position opposite to the recess 11 is pushed outward by the air pressure during blow molding.

[0237] A section perpendicular to the height direction of the inner preform 14 ( Figure 11D In such a cross-section, if the wall thickness of the inner bag 4 at the thin-walled portion 20a is set as t1, and the wall thickness of the inner preform 14 at the thick-walled portion 20b is set as t2, then the minimum value of T1 / T2 is preferably 0.8 or less. The minimum value of t1 / t2 is the minimum value calculated at each height position by moving the position of the cross-section along the height direction of the inner preform 14. The value of t1 / t2 is related to T1 / T2, and by reducing t1 / t2, T1 / T2 can be reduced. The value of t1 / t2 is preferably 0.1 or more. This value is, for example, 0.1 to 0.8, specifically, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or it can be within the range of any two values ​​exemplified here.

[0238] like Figure 10 As shown, the outer preform 13 is a bottomed cylindrical part with an opening 13a, a body 13b, and a bottom 13c. The bottom 13c is configured to close the lower end of the body 13b. An annular protrusion 13d and a positioning hole (not shown) are provided on the bottom 13c.

[0239] like Figures 12A-12D As shown, when forming the preform 15, the protrusion 14d abuts against the open end of the mouth 13a, and the positioning pin 14c1 is inserted into the positioning hole. Thus, the inner preform 14 and the outer preform 13 are positioned relative to each other. In this state, the mouths 14a and 13a face each other, and the body 14b and 13b face each other.

[0240] The openings 13a and 14a become the opening 15a of the preform 15, the body portions 13b and 14b become the body 15b of the preform 15, and the bottom portions 13c and 14c become the bottom portions 15c of the preform 15. In biaxial extension blow molding, primarily the body portion 15b and the bottom portion 15c are extended. However, biaxial extension blow molding is performed while the annular protrusion 13d is supported; therefore, the annular protrusion 13d and its inner region are essentially not extended during biaxial extension blow molding. After molding, the annular protrusion 13d becomes the annular protrusion 3b.

[0241] like Figure 11C as well as Figure 11D As shown, at the shoulder 6b of the container body 2 after biaxial extension blow molding, at least one of the outer surface of the inner preform 14 and the inner surface of the outer preform 13 is provided with a concave-convex shape 45. The concave-convex shape 45 can be provided in the portion including the shoulder 6b, and preferably in the portion including both the shoulder 6b and the bottom 7. Furthermore, it is preferable that the concave-convex shape 45 is smaller than the alternating wall thickness shape 20. In this embodiment, the concave-convex shape 45 is formed by a concave-convex shape 44 provided on the outer surface of the inner preform 14. Preferably, the concave-convex shape 44 is provided in the portion including the opening 14a, the body 13b, and the bottom 13c. No concave-convex shape is provided on the inner surface of the outer preform 13, but it is also possible to provide a concave-convex shape on the inner surface of the outer preform 13.

[0242] The raised / lower shape 45 is preferably formed by transferring the raised / lower shape formed on the mold to the inner preform 14 or the outer preform 13. The reverse shape of the raised / lower shape of the mold becomes the raised / lower shape transferred to the inner preform 14 or the outer preform 13. The inner preform 14 or the outer preform 13 is preferably formed by injection molding. In this case, the raised / lower shape of the mold can be easily and accurately transferred to the inner preform 14 or the outer preform 13. The raised / lower shape of the mold is preferably formed by sandblasting. As a result, fine raised / lower shapes can be formed on the mold. In addition, the raised / lower shape 45 can be formed by directly processing (e.g., sandblasting) the surface of the inner preform 14 or the outer preform 13.

[0243] <The inner preform 14 and the outer preform 13 engage at the opening 15a>

[0244] Furthermore, during biaxial stretch blow molding of the heated preform 15, the inner surface side of the preform 15 (i.e., the inner surface side of the inner preform 14) is typically supported. Methods for handling the preform 15 include upright handling with the bottom 15c facing downwards and inverted handling with the bottom 15c facing upwards; upright handling is generally preferred. On the other hand, if the preform 15 is handled upright, the outer preform 13 may detach from the inner preform 14 and fall off. If the outer preform 13 is securely fitted to the inner preform 14 at the opening 15a, the detachment of the outer preform 13 can be suppressed. However, in this case, a new problem arises in the container body 2 obtained by molding: the inner bag 4 becomes difficult to detach from the outer shell 3.

[0245] Therefore, in order to make it easy to pull out the inner bag 4 from the outer shell 3 after use and to prevent the outer preform 13 from falling off, in this embodiment, the inner preform 14 and the outer preform 13 are engaged at the opening 15a.

[0246] In this embodiment, such as Figures 12A-12D As shown, the engagement is the engagement of a protrusion 14f on the outer peripheral surface of the opening 14a of the inner preform 14 and a recess 13f on the inner peripheral surface of the opening 13a of the outer preform 13. The protrusion 14f and the recess 13f are respectively called protrusion 4f and recess 3f. A conical surface 14f1 called 4f1 is provided on the protrusion 14f. Therefore, the description of the protrusion 14f and the recess 13f is also valid for the protrusion 4f and the recess 3f as long as it does not contradict the main idea.

[0247] like Figures 12A-12D As shown, when the inner preform 14 is inserted into the outer preform 13, the protrusion 14f expands the opening edge of the outer preform 13 as it is inserted into the outer preform 13, engaging with the recess 13f. To reduce resistance during this engagement, a tapered surface 14f2 is provided on the lower side of the protrusion 14f (the side facing the outer preform 13). On the other hand, no tapered surface is provided on the upper side of the protrusion 14f. Therefore, after the protrusion 14f engages with the recess 13f, the engagement becomes difficult to disengage.

[0248] Alternatively, the conical surface 14f2 can be provided instead, or a conical surface can be provided on the opening edge of the outer preform 13 while providing the conical surface 14f1, thereby reducing the resistance when the protrusion 14f and the recess 13f engage. Furthermore, the engagement can also be the engagement of a recess on the outer peripheral surface of the inner preform 14 with a protrusion on the inner peripheral surface of the outer preform 13. Additionally, the recess 13f is formed by a through hole penetrating the outer preform 13, but it is sufficient that the recess 13f can engage with the protrusion 14f; it may not need to penetrate the outer preform 13.

[0249] <Materials and manufacturing methods of inner preform 14 and outer preform 13>

[0250] The inner preform 14 and the outer preform 13 can be formed by direct blow molding or injection molding of thermoplastic resins such as polyester (e.g., PET) or polyolefins (e.g., polypropylene, polyethylene). Preferably, the inner preform is made of a material with a larger molding shrinkage rate than the outer preform. In this case, the molding shrinkage creates a gap between the outer shell 3 and the inner bag 4, thereby facilitating the introduction of external gas into the intermediate space between the outer shell 3 and the inner bag 4.

[0251] In one example, the inner preform 14 is made of polyolefin (e.g., polypropylene), and the outer preform 13 is made of PET. Polyolefin has a larger molding shrinkage rate than PET; therefore, this resin structure facilitates the formation of a gap between the outer shell 3 and the inner bag 4. Furthermore, by using different materials for the inner preform 14 and the outer preform 13, welding during blow molding is suppressed.

[0252] Preferably, the laser marking agent is mixed into the material constituting the inner preform 14. In this case, the laser marking agent is also mixed into the inner bag 4 formed by molding the inner preform 14.

[0253] Furthermore, when the opening 14a of the inner preform 14 is made of polyolefin and the opening 13a of the outer preform 13 is made of amorphous PET, in biaxial stretch blow molding, the amorphous PET is crystallized by heating the opening 13a, thereby reducing the size of the opening 13a. On the other hand, the opening 14a is also heated, but polyolefin is a crystalline resin and has already crystallized to some extent before biaxial stretch blow molding. Therefore, even when heated in biaxial stretch blow molding, the dimensional change is smaller than that of amorphous PET. Therefore, the shrinkage of the opening 13a is more significant than that of the opening 14a, forming a gap between the protrusion 14d of the inner preform 14 and the opening end of the outer preform 13, which obstructs the clamping of the preform 15 by a pair of separate molds. In addition, for the container body 2 obtained after molding, Figure 4AThe protrusion 4c of the inner bag 4 shown forms a gap with the opening 3a of the outer shell 3, which may worsen the appearance. However, in this embodiment, the inner preform 14 and the outer preform 13 engage with each other at the opening 15a, so the inner bag 4 and the outer shell 3 also engage at the opening 5, suppressing the formation of the aforementioned gap.

[0254] Preferably, the inner preform 14 is formed by direct blow molding. Direct blow molding (using a molten cylindrical preform) allows for the easy formation of a layered structure of the inner preform 14. Preferably, the outer preform 13 is formed by injection molding. The preform 15 can be formed by combining the inner preform 14 and the outer preform 13 after they are formed separately, or it can be formed by two-color molding.

[0255] After biaxial stretch blow molding of the preform 15, by forming an external gas inlet hole 16 in the housing 3, it is possible to obtain Figure 1 The container body 2 shown.

[0256] Next, using a laser marking machine, information transmission displays 22 and 23 are printed on the container body 2. After that, after filling the inner bag 4 with contents, the double container 1 can be obtained by installing the mouth mounting member 8 on the mouth 5.

[0257] 2. Other implementation methods

[0258] In the above embodiment, the external gas inlet hole 16 is formed after biaxial extension blow molding, but a through hole as an external gas inlet hole can also be pre-formed on the outer preform 13.

[0259] An external gas inlet 16 can also be formed at the bottom of the housing 3.

[0260] From other perspectives, the present invention can be understood as an invention aimed at providing a double container 1 with an inner bag 4 that can be easily twisted to reduce its diameter. In this viewpoint, the structure of the inner bag 4 is not particularly limited, and therefore, it is not necessary for the inner bag 4 to rotate with the rotation of the opening mounting member 8. In this case, for example, the inner bag 4 can be rotated by pinching it with one's fingers. Therefore, the opening mounting member 8 can also be a cap or pump that does not have a structure for engaging with the inner bag 4. Furthermore, the container body 2 may not have a protrusion 4c; for example, a flange can be provided at the opening end of the inner bag 4 instead of a protrusion 4c, and this flange abuts against the opening end of the outer shell 3, thereby preventing the inner bag 4 from falling into the outer shell 3.

[0261] In the above embodiments, alternating wall thickness shapes 10 and 20 are achieved by forming concave strips 11 and 21. Alternatively, thick-walled portions can be formed by forming convex strips on one or both of the inner and outer surfaces of the inner bag 4 or the inner preform 14, thereby forming alternating wall thickness shapes 10 and 20. In this case, as the inner bag 4 twists, the thin-walled portions selectively bend, thus the bottom 7 becomes easily deformed into a corrugated shape and narrows in diameter.

[0262] The container body 2 can be formed by methods other than biaxial stretch blow molding, for example, by direct blow molding which can be formed by molding a stacked preform in a molten state.

[0263] 3. Matters unique to each viewpoint

[0264] (Third perspective)

[0265] (1) Second implementation method

[0266] use Figure 14 The second embodiment of the present invention will be described. This embodiment is similar to the first embodiment, and the following description will focus on the differences.

[0267] In this embodiment, such as Figure 14 As shown, the recess 3f is formed by a groove 3f1. The groove 3f1 extends between the end 3f2 on the opening end 3a side of the outer casing 3 and the end 3f3 on the inner side of the outer casing 3. Figure 2C The convex portion 4f shown is disposed within the groove 3f1, allowing it to move along the groove 3f1 towards the end portion 3f2. This releases the interlocking engagement between the convex portion 4f and the concave portion 3f. With this structure, the second resistance becomes very small. Furthermore, if the convex portion 4f reaches the end portion 3f2, it cannot move further along the groove 3f1 towards the inner side of the outer casing 3; therefore, the first resistance becomes very large.

[0268] Preferably, the inclination angle of the groove 3f1 is consistent with the inclination angle of the thread teeth of the external thread portion 5a1. In this case, when the opening mounting member 8 and the inner bag 4 are rotated together in the loosening direction, the protrusion 4f can move smoothly along the groove 3f1.

[0269] The recess 3f formed by the groove 3f1 can be obtained by forming the recess 13f of the outer preform 13 by the groove. In this case, by moving the protrusion 14f of the inner preform 14 along the groove, the protrusion 14f can engage with the recess 13f, and therefore the resistance during engagement becomes very small. If the groove of the outer preform 13 extends in the direction extending from the central axis of the opening 13a of the outer preform 13, the outer preform 13 becomes easier to detach from the inner preform 14. Therefore, it is preferable that the groove forming the recess 13f extends in a direction inclined relative to the central axis of the opening 13a of the outer preform 13.

[0270] Furthermore, the case where there is a recess on the outer shell 3 or the outer preform 13 is shown as an example here. However, when there is a recess on the inner bag 4 or the inner preform 14, the recess can also be used as a groove to achieve the same effect as described above.

[0271] (2) Invention of other viewpoints

[0272] In the biaxial stretch blow molding process, from the viewpoint that the outer preform 13 will not fall off even when the preform 15 is transported upright, and from the viewpoint that no gap will be generated between the protrusion 14d of the inner preform 14 and the outer preform 13, the following invention is derived.

[0273] A method for manufacturing a dual-container includes a biaxial stretch blow molding process, wherein,

[0274] In the biaxial stretch blow molding process, a preform consisting of an inner preform covered by an outer preform is heated to perform biaxial stretch blow molding, thereby forming the container body.

[0275] At the opening of the preform, the inner preform and the outer preform engage with each other.

[0276] In the container body 2 obtained by this approach, it is not necessary for the structure in which the first resistance to relative rotation of the inner bag 4 in one direction relative to the outer shell 3 at the opening 5 is greater than the second resistance to relative rotation in the other direction.

[0277] (An example of the fifth viewpoint)

[0278] 1. Manufacturing of container body 2

[0279] Based on the above method, by... Figures 10-13 The preform 15 shown is subjected to biaxial stretch blow molding to produce Figure 1The container body 2 shown has a capacity of 300 mL. The inner preform 14 is manufactured by injection molding a composition made of a random copolymer of propylene and ethylene (model: Wintec, manufactured by Nippon Polypropylene Co., Ltd.) containing 5% by mass of a laser marking agent (antimony-doped tin oxide / mica-containing grade, manufactured by Toyo Color Materials Co., Ltd.). The outer preform 13 is manufactured by injection molding PET (model: titanium catalyst grade, manufactured by Teijin Co., Ltd.) at 300°C to form the shape of the outer preform, followed by rapid cooling to 20°C. Rapid cooling transforms the molten PET into an amorphous state.

[0280] After heating such a preform 15 to 110°C (the temperature at the center of the preform 15 along its length), biaxial stretch blow molding is performed to obtain the container body 2.

[0281] 2. The information transmission displays the printed characters 22 and 23.

[0282] Using a fiber laser marking machine (laser wavelength 1064nm, model: LM-3200F, manufactured by Brother Industries), information transmission display 22 was printed on the container body 2. The laser irradiation conditions were 20W power (30%) and scanning speed 1500mm / s.

[0283] Next, an information transmission display 23 is printed on the container body 2 using a CO2 laser marking machine.

[0284] 3. Evaluation

[0285] Information display 22 is clearly printed on the inner pocket 4, but not on the outer shell 3. On the other hand, information display 23 is clearly printed on the outer shell 3, but not on the inner pocket 4.

[0286] (An example of the sixth viewpoint)

[0287] 1. Example 1

[0288] Based on the above method, by... Figures 10-13 The preform 15 shown is subjected to biaxial stretch blow molding to produce Figure 1The container body 2 shown has a capacity of 300 mL. The inner preform 14 is manufactured by injection molding of a propylene-ethylene random copolymer (model: Wintec, manufactured by Nippon Polypropylene Co., Ltd.). The outer preform 13 is manufactured by injection molding PET (model: titanium catalyst grade, manufactured by Teijin Co., Ltd.) at 300°C to form the shape of the outer preform, followed by rapid cooling to 20°C. Rapid cooling transforms the molten PET into an amorphous state. The mold forming the inner preform 14 is sandblasted to create an uneven shape on the surface corresponding to the outer surface of the inner preform 14. The sandblasting is performed using #80 (WA#80) white alumina.

[0289] After heating such a preform 15 to 110°C (the temperature at the center of the preform 15 along its length), biaxial stretch blow molding is performed to obtain the container body 2.

[0290] A test piece (10mm × 75mm) overlapping the inner bag 4 and outer shell 3 was cut from the obtained container body 2, and this test piece was placed on a friction coefficient measuring device (model: HEIDON-10, Shinto Science Co., Ltd.). More specifically, the inner bag 4 was fixed to the rising plate, and a 150g flat indenter was installed on the outer shell 3. Then, the rising plate was tilted, and the angle at the point when the outer shell 3 began to slide relative to the inner bag 4 was measured. The average angle obtained from measuring 3 samples was 18.8 degrees.

[0291] 2. Comparative Example 1

[0292] As for the mold used to form the inner preform 14, in addition to using a mold on which the surface corresponding to the outer surface of the inner preform 14 was mirror-polished, the angle at which the outer shell 3 began to slide relative to the inner bag 4 was measured using the same method as in Example 1. In any of the three samples, even when set to the device's measurement limit of 57.5 degrees, the outer shell 3 did not slide relative to the inner bag 4.

[0293] (Fourth viewpoint)

[0294] use Figures 15-22 The implementation of the fourth aspect of the present invention will be described.

[0295] 1. Double container 1 and preform 15

[0296] First, a double container 1 that can be manufactured by a double container manufacturing method according to an embodiment of the present invention will be described. For example... Figure 15As shown, the double container 1 that can be manufactured by the method of the present invention has a container body 2. The description of the container body 2 is the same as that described in "1. The First Embodiment Common to the First to Third, Fifth, and Sixth Viewpoints" except for the points stated below. Preferably, the container body 2 has an outer shell 3 and an inner bag 4, and is configured such that the inner bag 4 shrinks as the contents decrease.

[0297] The container body 2 has an inner bag 4 and an outer shell 3 configured to cover the inner bag 4. The portion of the inner bag 4, except for the flange 4b, is housed within the outer shell 3. The inner bag 4 abuts against the open end of the outer shell 3 via the flange 4b ​​and will not slip into the outer shell 3.

[0298] Preferably, an external gas inlet (not shown) is provided on the outer shell 3. The external gas inlet is a through hole that penetrates the outer shell 3. As the inner bag 4 contracts, external gas passes through the external gas inlet and is introduced into the intermediate space between the outer shell 3 and the inner bag 4, thereby allowing the inner bag 4 to contract without causing the outer shell 3 to contract. The external gas inlet can be provided at any position among the opening 5, body 6, and bottom 7.

[0299] like Figures 16-22 As shown, the container body 2 can be formed by heating the inner preform 14 and the outer preform 13, which become the outer shell 3, and covering the inner preform 14, which becomes the inner bag 4, to form a preform 15.

[0300] like Figure 16 As shown, the inner preform 14 is a bottomed cylindrical part, having an opening 14a, a body 14b, and a bottom 14c. A flange 14a1 is provided at the open end of the opening 14a. A locating pin 14c1 is provided at the bottom 14c.

[0301] like Figure 16 As shown, the outer preform 13 is a bottomed cylindrical shape, having an opening 13a, a body 13b, and a bottom 13c. A positioning hole 13c2 and a through hole 17 are provided in the bottom 13c. Figure 17B As shown, an annular protrusion 13c4 is provided on the outer surface of the bottom 13c. A positioning hole 13c2 and a through hole 17 are disposed in the region inside the annular protrusion 13c4. The outer preform 13 is configured to allow the inner preform 14 to be inserted. The through hole 17 serves as an external gas inlet for the container body 2.

[0302] like Figure 17A as well as Figure 17BAs shown, when forming the preform 15, the flange 14a1 abuts against the open end of the opening 13a, and the positioning pin 14c1 is inserted into the positioning hole 13c2. Thus, the inner preform 14 and the outer preform 13 are positioned relative to each other. In this state, the openings 14a and 13a face each other, and the body 14b and 13b face each other.

[0303] The openings 13a and 14a become the opening 15a of the preform 15, the body portions 13b and 14b become the body 15b of the preform 15, and the bottom portions 13c and 14c become the bottom portions 15c of the preform 15. Additionally, as... Figure 19 As shown, the body 15b and the bottom 15c become the extended portion 15d that is extended in the molding process described later.

[0304] The inner preform 14 and the outer preform 13 can be formed by direct blow molding or injection molding of thermoplastic resin.

[0305] The inner preform 14 has a polyolefin layer made of a polyolefin resin containing a polyolefin. The polyolefin content in the polyolefin resin is, for example, 60 to 100% by mass, specifically, for example, 60, 70, 80, 90, or 100% by mass, or within any two of the values ​​exemplified herein. Examples of polyolefins include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), homopolymer polypropylene (PP), propylene copolymers, cyclic polyolefins (COP), and mixtures thereof.

[0306] Propylene copolymers are copolymers between propylene and other monomers, and can be random copolymers or block copolymers, preferably random copolymers. Propylene copolymers can be obtained by copolymerizing a mixture of monomers. The propylene content in the monomer mixture is, for example, 60 to 99.5 mol%, specifically, for example, 60, 65, 70, 75, 80, 85, 90, 95, 96, 97, 98, 99, 99.5 mol%, or within any two of the values ​​exemplified herein. Ethylene is particularly preferred as the monomer for copolymerization with propylene.

[0307] The inner preform 14 can be a single-layer structure or a multi-layer structure. In the case of a single-layer structure, the inner preform 14 only has the aforementioned polyolefin layer. In the case of a multi-layer structure, the inner preform 14 has a laminated structure of the aforementioned polyolefin layer and other layers. Examples of other layers include a gas barrier resin layer and an adhesive resin layer. The adhesive resin layer is used to improve the adhesion between the polyolefin layer and the gas barrier resin layer.

[0308] The gas barrier resin layer is a layer composed of gas barrier resin. In this specification, gas barrier resin refers to a resin that, when set as a film with a thickness of 20 μm, withstands temperatures up to 20°C. Oxygen permeability is less than 50 cc / (m³) in an environment with 65% RH. 2 24 hours The resin has an oxygen permeability of (atm). For example, the oxygen permeability is 0~49 cc / (m³). 2 24 hours (atm), specifically, for example, 0.01, 0.1, 0.2, 0.5, 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 49 cc / (m 2 24 hours (atm) can also be within the range of any two values ​​exemplified here, or below any value.

[0309] As a gas barrier resin, it can be composed solely of a resin with high gas barrier properties such as EVOH (ethylene-vinyl alcohol copolymer) or polyamide, or it can be a mixture of the above resins and other resins.

[0310] The adhesive resin layer is a layer composed of an adhesive resin. Examples of adhesive resins include acid-modified polyolefin resins (such as maleic anhydride-modified polyethylene and maleic anhydride-modified polypropylene).

[0311] At the center of the length direction of the inner preform 14, the thickness of the polyolefin layer is in proportion to the overall wall thickness of the inner preform 14, for example, 50 to 100%, specifically, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100%, or it can be within any two values ​​exemplified herein.

[0312] The outer preform 13 has an amorphous PET layer composed of an amorphous PET-type resin containing amorphous PET. Amorphous PET is a substance formed by rapidly cooling molten PET (polyethylene terephthalate) to solidify it without crystallizing it. By rapidly cooling the outer preform 13 after molding it at a temperature above the melting peak temperature (around 270-280°C) using injection molding or similar methods, the PET constituting the outer preform 13 can be made amorphous. The content of amorphous PET in the amorphous PET-type resin is, for example, 60-100% by mass, specifically, for example, 60, 70, 80, 90, or 100% by mass, or within any two of the values ​​exemplified herein.

[0313] The outer preform 13 can be a single-layer structure or a multi-layer structure. In the case of a single-layer structure, the outer preform 13 only has the aforementioned amorphous PET layer. In the case of a multi-layer structure, the outer preform 13 has a laminated structure of the aforementioned amorphous PET layer and other layers. Examples of other layers include the aforementioned gas barrier resin layer and adhesive resin layer.

[0314] In this embodiment, if the temperature range between the crystallization peak temperature and the melting peak temperature of the polyolefin resin is set as the first temperature range, and the temperature range between the softening end temperature and the crystallization start temperature of the amorphous PET resin is set as the second temperature range, then the overlapping temperature range of the first temperature range and the second temperature range is 2°C or higher.

[0315] Figure 18A An example graph obtained from differential scanning calorimetry (DSC) of a polyolefin resin is shown (the graph obtained in Example 1). DSC can be performed according to JIS K7121:2012. The horizontal axis of the graph represents temperature, and the vertical axis represents endothermic or calorific value. In the first run, the measurement is performed while the sample is heated. The polyolefin resin is in a crystalline state at low temperature, and a melting peak is observed when the temperature is increased. The temperature of this melting peak is called the "melting peak temperature".

[0316] If the melting peak temperature is exceeded, the polyolefin resin becomes a liquid with very low viscosity. Then, in the second run, the temperature of the liquid polyolefin resin gradually decreases. At this point, a crystallization peak is observed. The temperature of this crystallization peak is called the "crystallization peak temperature." Polyolefin resins tend to become over-softened at temperatures higher than the melting peak temperature, and tend to be under-softened at temperatures lower than the crystallization peak temperature. Therefore, within the temperature range between the crystallization peak temperature and the melting peak temperature, the polyolefin resin reaches a softened state suitable for molding. This temperature range is called the first temperature range.

[0317] The crystallization peak temperature of the polyolefin resin is, for example, 80~117°C, preferably 90~110°C. Specifically, this temperature is, for example, 80, 85, 90, 95, 100, 105, 110, 115, 116, 117°C, or may be within the range of any two values ​​exemplified herein. The melting peak temperature of the polyolefin resin is, for example, 90~145°C, preferably 115~135°C. Specifically, this temperature is, for example, 90, 100, 110, 115, 120, 125, 130, 135, 140, 145°C, or may be within the range of any two values ​​exemplified herein. The first temperature range is, for example, 5~50℃, specifically, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50℃, or it can be within the range of any two values ​​exemplified here.

[0318] The crystallization peak temperature and melting peak temperature of polyolefin resins can be adjusted by changing the composition of the polyolefin resin. For example, compared with homopolymer polypropylene, propylene-ethylene random copolymer has a lower crystallization peak temperature and melting peak temperature. Therefore, by increasing the content of propylene-ethylene random copolymer in the polyolefin resin, the crystallization peak temperature and melting peak temperature can be reduced.

[0319] When the polyolefin resin is a mixture of multiple polyolefins, the crystallization peak temperature and melting peak temperature of the polyolefin resin become values ​​that reflect the individual crystallization peak temperature and melting peak temperature of each polyolefin. Therefore, for example, when the polyolefin resin includes polyolefins such as LLDPE and LDPE with low crystallization peak temperature and melting peak temperature, as well as homopolymer polypropylene, the crystallization peak temperature and melting peak temperature are lower compared to homopolymer polypropylene.

[0320] Figure 18B An example graph obtained by DSC of amorphous PET resin is shown (graph obtained by Example 1). The description of the DSC and graph is consistent with... Figure 18A same.

[0321] Amorphous PET resins are in an amorphous state at low temperatures. When heated, the softening start point, softening end point, crystallization start point, and crystallization peak appear in that order. The temperatures at which the softening start point, softening end point, crystallization start point, and crystallization peak appear are respectively the "softening start temperature", "softening end temperature", "crystallization start temperature", and "crystallization peak temperature".

[0322] The softening initiation point occurs at a temperature equivalent to the glass transition temperature (Tg). Around this point, the heat absorption increases (the negative slope of the DSC curve becomes more pronounced). The softening termination point occurs at a temperature where heat absorption no longer increases (i.e., the temperature at which the slope of the DSC curve changes from negative to zero). Between the softening initiation and termination points, amorphous PET resins gradually soften. At the softening termination temperature, amorphous PET resins reach a fully softened state.

[0323] If amorphous PET resin is further heated, a crystallization initiation point and a crystallization peak appear. The crystallization initiation point occurs at the temperature at which the amorphous PET resin begins to crystallize, and the slope of the DSC curve increases significantly around this point. The crystallization peak occurs at the temperature at which the crystallization of the amorphous PET resin ends. At temperatures higher than the crystallization initiation temperature, the crystallinity of the amorphous PET resin increases, thus losing its flexibility, and the softening of the amorphous PET resin becomes incomplete. Therefore, within the temperature range between the softening end temperature and the crystallization initiation temperature, the amorphous PET resin reaches a softened state suitable for molding. This temperature range is the second temperature range.

[0324] The softening end temperature of the amorphous PET resin is, for example, 70~90°C, preferably 75~85°C. Specifically, it is, for example, 70, 75, 80, 85, or 90°C, or any two of the values ​​exemplified herein. The crystallization start temperature of the amorphous PET resin is, for example, 110~130°C, preferably 115~125°C. Specifically, this temperature is, for example, 110, 115, 120, 125, or 130°C, or any two of the values ​​exemplified herein. The second temperature range is, for example, 30~50°C, preferably 35~45°C. Specifically, it is, for example, 30, 35, 40, 45, or 50°C, or any two of the values ​​exemplified herein.

[0325] In the reference example, the polyolefin resin is composed of homopolymer polypropylene, and the amorphous PET resin is composed of amorphous PET. In one example, the crystallization peak temperature of the homopolymer polypropylene is about 119°C, and the melting peak temperature is about 149°C; therefore, the first temperature range is 119~149°C. In one example, the softening end temperature of the amorphous PET is about 81°C, and the crystallization start temperature is about 120°C; therefore, the second temperature range is 81~120°C. Furthermore, the overlap temperature range between the first and second temperature ranges is about 1°C.

[0326] Within the overlap temperature range, both polyolefin resins and amorphous PET resins reach a softened state suitable for molding, thus molding is desired at temperatures within the overlap temperature range. However, in homopolymer polypropylene and amorphous PET, the overlap temperature range is a very narrow temperature range of about 1°C, making it difficult to mold at suitable temperatures for both.

[0327] The reason for the narrow overlap temperature range is that, compared to the second range, the first temperature range exists on the high-temperature side. By shifting the first temperature range towards the low-temperature side, the overlap temperature range can be expanded. As mentioned above, the crystallization peak temperature and melting peak temperature of the propylene-ethylene random copolymer are both lower than those of homopolymer polypropylene. Therefore, by including the propylene-ethylene random copolymer in polyolefin resins, the first temperature range can be shifted towards the low-temperature side, thus expanding the overlap temperature range. Alternatively, the first temperature range can also be shifted towards the low-temperature side by adding polyolefins with low crystallization peak temperatures, such as LLDPE or LDPE.

[0328] In the preform 15 of this embodiment, a polyolefin resin is selected such that the overlap temperature range is 2°C or higher (preferably 10°C). Therefore, compared with the case of the above-described reference example, both the polyolefin resin and the amorphous PET resin are easily molded at a molding temperature that is in a softened state suitable for molding. As a result, the shrinkage of the inner bag 4 can be suppressed during cooling after molding.

[0329] The overlapping temperature range is, for example, 2 to 40°C, preferably 4 to 40°C. Specifically, the overlapping temperature range is, for example, 2, 4, 5, 10, 15, 20, 25, 30, 35, or 40°C, or it can be within the range of any two values ​​exemplified herein or any value above such values.

[0330] 2. Manufacturing apparatus 40

[0331] Next, the manufacturing apparatus 40 that can be used in the manufacturing method of the dual container 1 according to one embodiment of the present invention will be described.

[0332] like Figures 19-22 As shown, the manufacturing apparatus 40 has a mold unit 50 and a plurality of heaters 61.

[0333] When the preform 15 approaches the heater 61, the plurality of heaters 61 are arranged adjacent to the side of the preform 15 in a manner that runs along the length of the preform 15. The output of the plurality of heaters 61 can be controlled independently of each other. Preferably, each heater 61 is positioned at... Figure 19 A rod-shaped object extending vertically from the paper surface.

[0334] The mold unit 50 has an opening support mold 51, a bottom support mold 52, and forming molds 53 and 54.

[0335] The mouth support mold 51 is configured to support the mouth 13a of the outer preform 13. An insertion hole 51a is provided within the mouth support mold 51, and a support rod 25 is inserted into the insertion hole 51a. The support rod 25 can extend and retract via a drive mechanism (not shown).

[0336] The mouth support mold 51 is configured to be able to, for example Figure 19 The position A near heater 61 shown is... Figure 20 The preform 15 can be moved between positions B, which are the molded dies 53 and 54 shown. Therefore, after the heating process of the preform 15 is performed at position A, the molding process of the preform 15 can be performed at position B. The opening support die 51 can rotate the preform 15 about the central axis of the opening 13a. By rotating the preform 15 while bringing it closer to the heater 61, the entire circumference of the preform 15 can be heated evenly. Alternatively, the heater 61 can be moved instead of the opening support die 51.

[0337] The bottom support mold 52 is driven by the drive mechanism 52c, thus enabling it to extend in the longitudinal direction ( Figures 20-22 The molds 53 and 54 can be opened and closed, and each has a cavity surface 53a and 54a. The cavity surfaces 53a and 54a are combined to form a cavity with a shape corresponding to the outer shape of the container body 2.

[0338] 3. Manufacturing method of double container 1

[0339] A method for manufacturing a double container 1 according to one embodiment of the present invention includes a heating step and a molding step. The molding step includes a bottom support step, an extension step, and a blow molding step.

[0340] <Heating Process>

[0341] In the heating process, the preform 15 is heated to soften it into a softened state. The heating process can be performed by heating the preform 15 with multiple heaters 61 while rotating the preform 15.

[0342] In one example, such as Figure 19As shown, with the preform 15 mounted on the opening support mold 51, the preform 15 can be heated by bringing it close to the heater 61. Since the opening 15a of the preform 15 is covered by the opening support mold 51, the body 15b and the bottom 15c (i.e., the extended portion 15d) are heated. Furthermore, before the heating process, the front end of the support rod 25 can be brought into contact with the inner bottom surface of the inner preform 14. This suppresses the shaking of the softened preform 15.

[0343] Preferably, the heating temperature of the preform 15 is within the aforementioned overlapping temperature range. This allows both the outer preform 13 and the inner preform 14 to be in a softened state suitable for molding.

[0344] <Bottom Support Process>

[0345] In the bottom support process, such as Figures 20-21 As shown, the bottom support mold 52 moves toward the bottom 13c of the outer preform 13, supporting the bottom 13c of the outer preform 13. The bottom support mold 52 is provided with a recess 52a capable of accommodating the annular protrusion 13c4. Preferably, the bottom support mold 52 supports the bottom 13c in such a way that the annular protrusion 13c4 is accommodated within the recess 52a. This prevents the annular protrusion 13c4 and its inner region from extending during the blow molding process. Preferably, the recess 52a is annular. Furthermore, it is preferable that the bottom support mold 52 has a recess 52b capable of accommodating the positioning pin 14c1, supporting the bottom 13c in such a way that the positioning pin 14c1 is accommodated within the recess 52b. This prevents interference between the positioning pin 14c1 and the bottom support mold 52. Figure 21 The molds 53 and 54 are shown in the closed state, but the molds 53 and 54 can be closed at any time before the blow molding process, so they can also be closed after the longitudinal extension process.

[0346] <Vertical Extension Process>

[0347] In the vertical extension process, such as Figures 21-22 As shown, by pressing the support rod 25 against the inner bottom surface of the inner preform 14 and elongating it, the preform 15 is elongated in the longitudinal direction ( Figure 22 The preform 15 extends in the vertical direction. At this time, it is preferable to retract the bottom support mold 52 and the support rod 25 synchronously. This allows for stable extension of the preform 15. Furthermore, the longitudinal extension process can be performed without supporting the bottom 13c via the bottom support mold 52; therefore, the bottom support process can be performed after the longitudinal extension process. Additionally, a recess for inserting the support rod can be provided on the inner bottom surface of the inner preform 14, making it easier to fix the support rod to the inner preform 14.

[0348] <Blow Molding Process>

[0349] In the blow molding process, from Figure 22 Air is blown into the preform 14 in a certain state, causing the preform 15 to extend laterally (i.e. expand) and be shaped into the cavity surfaces 53a and 54a. The air can be blown in by passing through the ventilation passage 26 between the opening support mold 51 and the support rod 25. For example, a ventilation passage can also be provided in the support rod 25 to blow air in from the side of the support rod 25.

[0350] In this embodiment, air is blown in while the bottom 13c of the outer preform 13 is supported by the bottom support mold 52, thereby suppressing the extension of the bottom 13c of the outer preform 13.

[0351] Furthermore, the blow molding process can be performed simultaneously with the longitudinal extension process. That is, air can be blown into the preform 14 while the preform 15 is being extended longitudinally. Alternatively, the longitudinal extension process can be omitted, and after the bottom support process, the preform 15 can be extended longitudinally without blowing air directly.

[0352] Through blow molding, the preform 15 expands to obtain... Figure 15 The container body 2 is shown. The openings 13a and 14a become the opening 5, the body parts 13b and 14b become the body 6, and the bottom parts 13c and 14c become the bottom 7. During blow molding, the openings 13a and 14a, the annular protrusion 13c4, and the area inside them remain largely undeformed; deformation mainly occurs in other parts. For example... Figure 15 As shown, flange 14a1 becomes flange 4b ​​that covers the opening end of mouth 5 of container body 2.

[0353] (An example of the fourth viewpoint)

[0354] <Reference Example 1>

[0355] According to the above method, by using Figures 19-22 The manufacturing apparatus shown is 40 pairs. Figures 16-16 The preform 15 shown in Figure 7 is subjected to biaxial stretch blow molding to produce... Figure 15 The container body 2 shown has a capacity of 300 mL. The inner preform 14 is manufactured by injection molding homopolymer polypropylene (model: Novatec, manufactured by Nippon Polypropylene Co., Ltd.). The outer preform 13 is manufactured by injection molding PET (model: titanium catalyst grade, manufactured by Teijin Co., Ltd.) at 300°C to form the shape of the outer preform, followed by rapid cooling to 20°C. Through rapid cooling, the molten PET is transformed into an amorphous state.

[0356] The crystallization peak temperature of homopolymer polypropylene is approximately 119°C, and the melting peak temperature is approximately 149°C; therefore, the first temperature range is 119~149°C. The softening end temperature of amorphous PET is approximately 81°C, and the crystallization start temperature is approximately 120°C; therefore, the second temperature range is 81~120°C. Furthermore, the overlap temperature range between the first and second temperature ranges is approximately 1°C.

[0357] After heating such a preform 15 to 110°C (the temperature at the center of the preform 15 along its length), biaxial stretch blow molding is performed to obtain the container body 2.

[0358] After the container body 2 was cooled to room temperature, the state of the inner bag 4 was checked at the bottom of the container body 2. As a result, due to the shrinkage of the inner bag 4, a gap of about 2 mm was created between the inner bag 4 and the outer shell 3.

[0359] <Example 1>

[0360] Except for changing the material of the inner preform 14, the container body 2 is manufactured in the same way as in Reference Example 1.

[0361] In Example 1, the inner preform 14 was manufactured by injection molding of a propylene-ethylene random copolymer (model: Wintec, manufactured by Nippon Polypropylene Co., Ltd.). The crystallization peak temperature of the propylene-ethylene random copolymer is approximately 100°C, and the melting peak temperature is approximately 125°C; therefore, the first temperature range is 100~125°C. Furthermore, the overlap temperature range between the first and second temperature ranges is 20°C.

[0362] After heating such a preform 15 to 110°C (the temperature at the center of the preform 15 along its length), biaxial stretch blow molding is performed to obtain the container body 2.

[0363] After the container body 2 was cooled to room temperature, the state of the inner bag 4 was checked at the bottom of the container body 2. As a result, due to the shrinkage of the inner bag 4, the gap between the inner bag 4 and the outer shell 3 was less than 1 mm. This result indicates that, compared with Reference Example 1, the shrinkage of the inner bag 4 during cooling after molding was suppressed in Example 1.

[0364] (Seventh viewpoint)

[0365] use Figures 23-27B This describes an embodiment of the seventh aspect of the present invention.

[0366] 1. Structure of Double Container 1

[0367] <Basic Structure>

[0368] like Figures 23-25EAs shown, a dual container 1 according to one embodiment of the present invention has a container body 2. The description of the container body 2 is the same as that described in "1. The First Embodiment Common to the First to Third, Fifth and Sixth Views" except for the points mentioned below.

[0369] Regarding the inner bag 4 of the container body 2, the portion other than the flange 4n is housed within the outer shell 3. Apart from this, the description of the basic structure of the container body 2 is the same as that described in "1. The First Embodiment Common to the First to Third, Fifth, and Sixth Viewpoints".

[0370] <Easy-to-expand diameter section 36>

[0371] An expandable portion 36 is provided at the opening 5 of the outer casing 3, which facilitates the expansion of the opening 5 of the outer casing 3 when the inner bag 4 is pulled out from the outer casing 3. The expandable portion 36 is the part that makes it easy to expand the opening 5 of the outer casing 3. In this embodiment, the expandable portion 36 is formed by a slit 37 provided at the opening 5 of the outer casing 3, but it can also be other structures. Examples of expandable portions 36 include (a) a structure in which the slit 37 is filled with a filling material, (b) a long and thin section, and (c) a long and thin-walled section. As the filling material in (a), a material with a lower strength than the opening 5 of the outer casing 3 can be used. In the case of structures such as (a) to (c), if a radial force is applied to the opening 5 of the outer casing 3, the expandable portion 36 is broken or extended, thereby expanding the opening 5 of the outer casing 3.

[0372] The expandable diameter portions 36 are preferably provided in the opening 5 of the outer casing 3 at multiple locations separated in the circumferential direction (four locations in this embodiment). Preferably, the multiple expandable diameter portions 36 are arranged at equal intervals in the circumferential direction. The number of expandable diameter portions 36 is, for example, 1 to 8, preferably 2 to 6, specifically, for example, 1, 2, 3, 4, 5, 6, 7, 8, or any two values ​​exemplified herein. The width of the slit 37 is, for example, 0 to 1 mm, specifically, for example, 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0 mm, or any two values ​​exemplified herein. When the width of the slit 37 is 0 mm, the slit 37 is formed by a cut in the outer casing 3. By providing the easily expandable diameter section 36, the opening 5 of the outer shell 3 becomes easier to expand when the inner bag 4 is pulled out from the outer shell 3, reducing the force required to pull out the inner bag 4.

[0373] Preferably, the easily expandable portion 36 is configured to span the opening 5 and shoulder 6b of the housing 3. This is because, in this case, the opening 5 of the housing 3 is easily expandable.

[0374] Furthermore, if the opening 5 of the outer shell 3 is enlarged before the contents of the double container 1 are completely used up, the ease of use and aesthetics of the double container 1 may be compromised. Therefore, as... Figures 25A-25B As shown, a diameter expansion suppression part 38 is provided on the double container 1. This diameter expansion suppression part 38 suppresses the expansion of the opening 5 of the outer shell 3 before the inner bag 4 is pulled out. As long as the diameter expansion suppression part 38 is a structure that suppresses the expansion of the opening 5 of the outer shell 3, its structure is not particularly limited. In this embodiment, the diameter expansion suppression part 38 is formed by engaging the flange 4n of the inner bag 4 with the opening end 3a of the outer shell 3.

[0375] The flange 4n is a portion extending radially outward from the opening end 4o of the inner bag 4, and is preferably formed in an annular shape. The flange 4n abuts against the opening end 3a. An annular groove 4n1 is preferably provided on the underside of the flange 4n, and an insertion portion 3n formed by thinning the outer shell 3 is provided at the opening end 3a of the outer shell 3. By inserting the insertion portion 3n into the groove 4n1, the flange 4n of the inner bag 4 can engage with the opening end 3a of the outer shell 3.

[0376] When removing inner bag 4, firstly, as Figures 25C-25D As shown, the inner bag 4 is slightly lifted, causing the insertion part 3n to disengage from the groove 4n1. This releases the engagement between the flange 4n and the opening end 3a, allowing the opening 5 of the outer casing 3 to expand. The distance by which the inner bag 4 is lifted is, for example, 0.1 to 3 mm, specifically, for example, 0.1, 0.3, 0.5, 1.0, 1.5, 2.0, 2.5, or 3.0 mm, or any two of the values ​​exemplified here. The structure used to lift the inner bag 4 is not particularly limited. The inner bag 4 can be lifted by hand by lifting the flange 4n, by lifting the pull tab attached to the flange 4n, or by using an opening mounting member such as a pump or cap. A conical surface 3o is provided adjacent to the insertion part 3n, and a gap 39 is formed between the conical surface 3o and the lower surface of the flange 4n. By hooking a finger around the flange 4n in the gap 39, the inner bag 4 can be easily lifted.

[0377] When using the opening mounting member to lift the inner bag 4, for example, the threaded opening mounting member is screwed into the engaging part 5a and engaged with the inner bag 4. In this state, rotating the opening mounting member in the direction of disassembly from the engaging part 5a allows the inner bag 4 to be lifted. In this case, the inner bag 4 becomes smaller due to being twisted, making it easier to pull out the inner bag 4.

[0378] Next, as Figure 25EAs shown, the opening 5 of the outer casing 3 is enlarged to pull the outer casing 3 out of the inner bag 4. The opening 5 of the outer casing 3 can be enlarged by applying a radially outward force to the opening 5 of the outer casing 3 through the inner bag 4 when the inner bag 4 is pulled out, or it can be enlarged using other clamps or the like.

[0379] Furthermore, when the inner bag 4 shrinks as its contents are discharged, it is preferable to introduce external gas into the intermediate space between the outer shell 3 and the inner bag 4 to prevent the outer shell 3 from shrinking. If the expandable diameter portion 36 is a ventilated structure like the slit 37, external gas can be introduced into the intermediate space through the expandable diameter portion 36. If the expandable diameter portion 36 is not ventilated, it is preferable to provide an external gas inlet hole for introducing external gas into the intermediate space between the outer shell 3 and the inner bag 4. The external gas inlet hole can be provided, for example, in the body or bottom.

[0380] 2. Method for manufacturing double container 1

[0381] like Figures 26-27B As shown, the container body 2 can be manufactured in the same manner as described in "1. First Embodiment Common to First, Third, Fifth and Sixth Viewpoints" except for the following points.

[0382] <Structure of inner preform 14, outer preform 13, and preform 15>

[0383] like Figure 26 As shown, a flange 14i is provided at the open end of the opening 14a of the inner preform 14. The flange 14i does not deform during molding and remains in its original shape as the flange 4n. Therefore, the matters described for the flange 4n also apply to the flange 14i.

[0384] like Figure 26 As shown, a positioning hole 13k is provided at the bottom 13c of the outer preform 13 (in Figure 27B (See diagram). A slit 13g is provided on the outer preform 13, spanning the opening 13a and the body 13b. The slit 13g becomes a slit 37 after molding.

[0385] like Figure 27A as well as Figure 27B As shown, during the formation of the preform 15, the flange 14i abuts against the open end of the opening 13a, and the locating pin 14c1 is inserted into the locating hole. Thus, the inner preform 14 and the outer preform 13 are positioned relative to each other. In this state, the openings 14a and 13a face each other, and the bodies 14b and 13b face each other. Figure 27B As shown, a flange 14i engages with the open end 13j of the outer preform 13. This prevents the opening 13a of the outer preform 13 from expanding during molding.

[0386] (Eighth viewpoint)

[0387] use Figures 28A to 38 The implementation of the eighth aspect of the present invention will be described.

[0388] 1. First Implementation Method

[0389] 1-1. Structure of Double Container 1

[0390] <Basic Structure>

[0391] like Figure 28A as well as Figure 28B As shown, the dual container 1 of the first embodiment of the present invention has a container body 2 and a mouth mounting member 8. The description of the container body 2 and the mouth mounting member 8 is the same as that described in "1. First Embodiment Common to First, Third, Fifth and Sixth Viewpoints" except for the points mentioned below.

[0392] like Figure 30A As shown, the inner diameter D2 of the opening 5 of the outer casing 3 is, for example, 20-50 mm, preferably 25-40 mm. The outer diameter D4 of the opening 5 of the outer casing 3 is, for example, 25-55 mm, preferably 30-45 mm. Specifically, the inner diameter D2 is, for example, 20, 25, 30, 35, 40, 45, 50 mm; specifically, the outer diameter D4 is, for example, 25, 30, 35, 40, 45, 50, 55 mm, or any two of the values ​​shown herein. The length of the opening 5 is, for example, 15-35 mm; specifically, for example, 15, 20, 25, 30, 35 mm, or any two of the values ​​shown herein.

[0393] like Figure 30A As shown, the body 6 has a curved portion 6f that bends outward. The curved portion 6f is located at or near the boundary between the shoulder 6b and the body 6c. If the diameter of the container body 2 at the portion 6f1 where the radius of curvature at the curved portion 6f is the smallest is set as D, and the radius of curvature at portion 6f1 is set as R, then R / D is preferably 0.5 or more (0.73 in this embodiment). The larger this value is, the larger the radius of curvature R becomes relative to the diameter D, and the curved portion 6f bends more gently. Near the curved portion 6f, the inner bag 4 can be prevented from being pressed against the outer shell 3, reducing the force required to pull out the inner bag 4. R / D can be, for example, 0.5 to 2, specifically, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, or any two values ​​listed here, or any value above that.

[0394] Furthermore, it is preferable that D / D2 is 1.8 or less (1.4 in this embodiment). The smaller this value, the easier it is for the curved portion 6f to pass through the opening 5, thus reducing the force required to pull out the inner bag 4. D / D2 is, for example, 1.1 to 1.8, specifically, for example, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, or it can be within the range of any two values ​​exemplified herein.

[0395] Preferably, the inclination angle α of the shoulder 6b relative to the central axis of the opening is 25 degrees or less (19 degrees in this embodiment). The smaller the inclination angle α, the better the inner bag 4 is prevented from being pressed against the outer shell 3 near the bend 6f, and the less force is required to pull out the inner bag 4. The inclination angle α is, for example, 5 to 25 degrees, specifically, for example, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 degrees, or it can be within the range of any two values ​​exemplified herein or below any value.

[0396] like Figure 28A as well as Figure 28B As shown, the body 6 has a tapered section 6g that tapers towards the bottom 7 on the side closer to the bottom 7 than the curved section 6f. The tapered section 6g functions as a so-called "demolding draft angle," reducing the force required to pull out the inner bag 4. In this embodiment, the body 6c has a tapered shape towards the bottom 7, therefore, the entire body 6c becomes the tapered section 6g. On the other hand, for example, a portion of the body 6c may not taper, while the remaining portion tapers. The portion that does not taper is the portion whose outer diameter does not change.

[0397] <The uneven shape of the inner surface of the mouth 5>

[0398] like Figure 31C As shown, preferably, at least one of the inner surfaces of the mouth 5 and the body 6 at a position adjacent to the mouth 5 is provided with a concave-convex shape 9, which is a shape in which concave strips 9a and convex strips 9b alternate in the circumferential direction of the mouth 5.

[0399] <Structure of the bottom 7>

[0400] like Figure 30B As shown, a protrusion 4e is provided at the bottom 7 of the inner bag 4.

[0401] <Appearance Design>

[0402] The container body 2 has a novel and beautiful appearance. Figures 32A-32FThe exterior design of the container body 2 shown can be viewed as an overall design, or as part of area A (to be registered as a partial design), part of area B (to be registered as a partial design), and other parts (to be registered as partial designs). For convenience, only the front view is shown for areas A and B, but the intention is to consider the entire circumference of the container body 2 as part of the design to be registered.

[0403] At the bottom 7, the area C containing the bottom recessed area 7a may or may not be included in the "part for which design registration is desired as a partial design".

[0404] <The engaging structure between the mouth mounting component 8 and the inner bag 4, and the engaging structure between the inner bag 4 and the outer shell 3 at the mouth 5>

[0405] like Figure 28A as well as Figure 28B As shown, the inner bag 4 has a protrusion 4c that protrudes from the opening end 3a of the outer shell 3.

[0406] like Figure 33A as well as Figure 33B As shown, the mouth mounting component 8 has an outer cylinder 8a, an inner cylinder 8c, a locking part 8d, a claw part 8e, a top plate 8f, and a discharge port 8j.

[0407] The outer surface of the outer cylinder 8a has an alternating pattern of raised and recessed areas in the circumferential direction. This facilitates the rotation of the opening mounting member 8. An engaging portion 8d is provided on the inner surface of the outer cylinder 8a. The engaging portion 8d engages with the engaging portion 5a of the opening 5. By engaging the engaging portion 8d with the engaging portion 5a, the opening mounting member 8 is mounted to the opening 5.

[0408] The upper surface of the outer cylinder 8a is covered by a top plate 8f. An outlet 8j is provided on the top plate 8f. A nozzle may also be provided on the outlet 8j. The inner cylinder 8c is a so-called inner ring, with a diameter smaller than that of the outer cylinder 8a and disposed inside the outer cylinder 8a.

[0409] A claw portion 8e is provided on the inner surface of the outer cylinder 8a. Multiple claw portions 8e are arranged separately in the circumferential direction (eight in this embodiment). The number of claw portions 8e is, for example, 1 to 20, preferably 4 to 12. A through hole 8h is provided on the top plate 8f at a position facing the claw portions 8e.

[0410] The opening mounting member 8 of this shape can be manufactured using a split mold that opens and closes in the vertical direction. The through hole 8h and the upper surface 8e1 of the claw portion 8e can be formed using a protrusion provided on the upper mold, therefore, the claw portion 8e can be formed without forcibly pulling out the lower mold. Therefore, the protrusion of the claw portion 8e does not need to be set to a protrusion that can be forcibly pulled out, but can be set to a protrusion suitable for engaging with the inner bag 4 (e.g., 1 mm or more).

[0411] In this embodiment, the engaging portion 5a is an externally threaded portion 5a1, and the engaging portion 8d is an internally threaded portion 8d1 that can engage with the externally threaded portion 5a1. Therefore, by rotating the mouth-mounting member 8 relative to the mouth 5 in the fastening direction (usually clockwise when viewed from above) (hereinafter, the relative rotation relative to the mouth 5 will be simply referred to as "rotation"), the mouth-mounting member 8 can be mounted on the mouth 5. If the mouth-mounting member 8 is rotated in the fastening direction, then Figure 35A The outer circumferential surface of the inner cylinder 8c is tightly pressed against the inner circumferential surface of the inner bag 4, and the internal thread 8d1 is screwed into the external thread 5a1. At this time, if the opening 5 of the inner bag 4 rotates together with the opening mounting member 8 due to friction between the outer circumferential surface of the inner cylinder 8c and the inner circumferential surface of the inner bag 4, the inner bag 4 will be twisted. At the point before the opening mounting member 8 is installed, the inner bag 4 is filled with contents; if the inner bag 4 is twisted, the contents will overflow. To prevent this problem, the inner bag 4 can be tightly fitted to the outer shell 3 in the opening 5 without rotating relative to the outer shell 3. However, if only a tight fit is achieved, a new problem arises: it becomes difficult to pull the inner bag 4 out of the outer shell 3.

[0412] Therefore, in this embodiment, a structure is adopted in which the first resistance to relative rotation of the inner bag 4 relative to the outer shell 3 in one direction is greater than the second resistance to relative rotation in the other direction. For example, when the external thread 5a1 is a right-hand thread, one direction and the other direction are the clockwise and counterclockwise directions when viewed from the upper side of the container body 2, respectively. In other words, one direction is the tightening direction of the mouth mounting member 8, and the other direction is the loosening direction of the mouth mounting member 8. According to this structure, when the mouth mounting member 8 is installed, it is difficult for the inner bag 4 to rotate relative to the outer shell 3, thus suppressing the problem of the inner bag 4 being twisted when the mouth mounting member 8 is installed. In addition, since the second resistance to relative rotation in the other direction is relatively small, when separating the inner bag 4 from the outer shell 3 after use, by rotating the mouth 5 of the inner bag 4 relative to the outer shell 3 in the other direction, the inner bag 4 can be easily twisted and its diameter reduced, thereby easily pulling the inner bag 4 out of the outer shell 3.

[0413] Specifically, the inner bag 4 and the outer shell 3 engage with each other at the opening 5, and this engagement creates a first resistance greater than a second resistance. More specifically, as... Figure 31B As shown, the interlocking mechanism is the engagement of a protrusion 4f on the outer peripheral surface of the inner bag 4 and a recess 3f on the inner peripheral surface of the outer shell 3. Figure 31B As shown, on the clockwise side (fastening direction side) of the protrusion 4f, an inwardly protruding protrusion 3g is provided on the outer shell 3. Conversely, no such protrusion is provided on the counterclockwise side (loosening direction side) of the protrusion 4f. Therefore, in the opening 5, the resistance (first resistance) for rotating the inner bag 4 relative to the outer shell 3 in the fastening direction is greater than the resistance (second resistance) for rotating in the loosening direction. In this embodiment, two groups of protrusions 4f and recesses 3f can be provided at 180-degree intervals, but the number of groups of protrusions 4f and recesses 3f can be one or more.

[0414] Furthermore, the interlocking mechanism can be the engagement of a recess on the outer periphery of the inner bag 4 and a protrusion on the inner periphery of the outer shell 3. Additionally, the recess 3f is formed by a through hole penetrating the outer shell 3, but the recess 3f can be any component capable of engaging with the protrusion 4f, and may not even penetrate the outer shell 3.

[0415] If the mouth-mounting component 8 is rotated further in the tightening direction, the internal thread 8d1 engages with the external thread 5a1 on one side, while the claw 8e gradually approaches the protrusion 4c. At a certain point in time, the inclined surface located on the lower side of the claw 8e and... Figure 28B The engaging flange 4c3 shown abuts against the jaws. In this state, if the mouth mounting member 8 is rotated further in the tightening direction, the claw 8e passes over the engaging flange 4c3, becoming... Figure 35A The state shown. In this state, the claw portion 8e is positioned between the engaging flange 4c3 and the abutting flange 4c4. The engaging flange 4c3 is accommodated in the gap between the claw portion 8e and the top plate 8f. Figure 35A As shown, the protruding cylinder 4c1 is positioned between the claw portion 8e and the inner cylinder 8c. At this point in time, before the external thread portion 5a1 and the internal thread portion 8d1 are fully tightened, the claw portion 8e is guided by the circumferentially inclined surface 4c5 of the engaging protrusion 4c2 and passes over the engaging protrusion 4c2, thereby allowing the mouth mounting member 8 to rotate further in the tightening direction. After the external thread portion 5a1 and the internal thread portion 8d1 are fully tightened, the mouth mounting member 8 cannot rotate in the tightening direction and cannot move axially in the mouth portion 5.

[0416] In this state, the engaging protrusion 4c2 engages with the claw portion 8e of the mouth mounting member 8 in the rotational direction of the mouth mounting member 8, and the engaging flange 4c3 engages with the claw portion 8e of the mouth mounting member 8 in the axial direction of the mouth 5. That is, the claw portion 8e engages with the engaging protrusion 4c2 and the engaging flange 4c3.

[0417] Therefore, after the contents of the inner bag 4 are used up, if the opening mounting member 8 is rotated in the loosening direction (usually counterclockwise when viewed from above), the inner bag 4 will rotate along with the opening mounting member 8. As a result, the inner bag 4 is twisted and its diameter is reduced.

[0418] If the opening mounting member 8 is rotated further in the loosening direction and the engagement between the internal thread 8d1 and the external thread 5a1 is released, the opening mounting member 8 can move in a direction away from the opening end 3a (i.e., in the axial direction of the opening 5). The engaging flange 4c3 engages with the opening mounting member 8 in the axial direction of the opening 5. Therefore, if the opening mounting member 8 is moved in the axial direction of the opening 5, the inner bag 4 also moves with the opening mounting member 8, and the inner bag 4 is pulled out from the outer shell 3.

[0419] As described above, according to the structure of this embodiment, the inner bag 4 can be pulled out from the outer shell 3 after the inner bag 4 is twisted and its diameter is reduced simply by rotating the mouth mounting member 8 in the loosening direction. Therefore, the inner bag 4 can be smoothly separated from the outer shell 3 with simple operation.

[0420] <Anti-loosening structure of mouth mounting component 8>

[0421] In the container body 2 of this embodiment, the external threaded portion 5a1 and the internal threaded portion 8d1 are formed with multiple threads (more specifically, three threads), so even after the external threaded portion 5a1 and the internal threaded portion 8d1 are tightened, they are prone to loosening. Therefore, as Figure 35B As shown, an anti-loosening structure 24 is provided to prevent loosening of the screw thread between the opening 5 and the opening mounting member 8. In this embodiment, the anti-loosening structure 24 consists of a protrusion 3i protruding from the outer peripheral surface of the outer shell 3 and a protrusion 8i protruding from the inner peripheral surface of the outer cylinder 8a of the opening mounting member 8. Preferably, multiple protrusions 3i and 8i are evenly separated in the circumferential direction (three in this embodiment). The anti-loosening structure 24 can be other structures that engage the opening 5 and the opening mounting member 8 in the circumferential direction. For example, the recess on the inner peripheral surface of the outer cylinder 8a of the opening mounting member 8 can engage with the protrusion 3i.

[0422] <Protrusion 3h on the inner surface of the opening 5 of the outer shell 3>

[0423] like Figure 31AAs shown, a protrusion 3h is provided on the inner surface of the opening 5 of the outer shell 3, closer to the opening end 3a than the protrusion 3g. Preferably, the protrusion 3h is connected to the protrusion 3g. At the locations where the protrusions 3g and 3h are provided, the opening 5 of the outer shell 3 is thinned, and the outer shell 3 only abuts against the inner bag 4 at the protrusions 3g and 3h. Therefore, the contact area between the outer shell 3 and the inner bag 4 can be reduced, and the force required to pull out the inner bag 4 can be reduced. In addition, preferably, the protrusions 3g and 3h are evenly spaced in the circumferential direction and provided at multiple locations (two locations in this embodiment). This allows the opening 5 of the outer shell 3 and the opening 5 of the inner bag 4 to be kept concentric.

[0424] Furthermore, if the opening mounting member 8 is rotated in the loosening direction, the engagement between the opening mounting member 8 and the opening 5 can be released with approximately half a turn. Once this engagement is released, the inner bag 4 can be pulled out of the outer casing 3. However, this may cause the following problem: sometimes the release of the engagement is not immediately noticed, causing the opening mounting member 8 to spin freely. On the other hand, in this embodiment, if the protrusion 4f is rotated in the loosening direction (… Figures 31A-31B If rotated counterclockwise, the convex part 4f will reach the protrusion 3h in approximately half a turn (e.g., Figure 31B The right-side protrusion 4f reaches Figure 31A The protrusion on the left side (3h) prevents further rotation of the inner bag 4. With this structure, when the opening mounting member 8 is rotated in the loosening direction, the inner bag 4 can be pulled out at the point when it becomes unable to rotate, thus making it possible to pull out the inner bag 4 at the appropriate time and improving ease of use.

[0425] 1-2. Method for manufacturing double container 1

[0426] like Figures 36-38 As shown, the container body 2 can be manufactured in the same manner as described in "1. First Embodiment Common to First, Third, Fifth and Sixth Viewpoints" except for the following points.

[0427] <Structure of inner preform 14, outer preform 13, and preform 15>

[0428] like Figure 36 As shown, the inner preform 14 is a bottomed cylindrical shape, having an opening 14a, a body 14b, and a bottom 14c. Figure 37 As shown, the inner surface of the inner preform 14 is provided with a concave-convex shape 19.

[0429] like Figure 36As shown, the outer preform 13 is a bottomed cylindrical part with an opening 13a, a body 13b, and a bottom 13c. The opening 13a of the outer preform 13 is provided with a protrusion 13h that is a protrusion 3h, a protrusion (not shown) that is a protrusion 3g, and a protrusion 13i that is a protrusion 3i.

[0430] like Figure 38 As shown, when forming the preform 15, the protrusion 14d abuts against the open end of the mouth 13a, and the positioning pin 14c1 is inserted into the positioning hole.

[0431] <The inner preform 14 and the outer preform 13 engage at the opening 15a>

[0432] In this embodiment, such as Figure 36 As shown, the engagement is the engagement of a protrusion 14f on the outer peripheral surface of the opening 14a of the inner preform 14 and a recess 13f on the inner peripheral surface of the opening 13a of the outer preform 13. The protrusion 14f and the recess 13f are respectively called protrusion 4f and recess 3f.

[0433] 2. Other implementation methods

[0434] The container body 2 can be formed by methods other than biaxial extension blow molding, for example, by direct blow molding of a molten preform.

[0435] (Ninth viewpoint)

[0436] use Figures 39-48 This describes an embodiment of the ninth aspect of the present invention.

[0437] 1. First Implementation Method

[0438] 1-1. Structure of Double Container 1

[0439] <Basic Structure>

[0440] like Figure 39 As shown, the dual container 1 of the first embodiment of the present invention has a container body 2 and a mouth mounting member 8. The description of the container body 2 and the mouth mounting member 8 is the same as that described in "1. First Embodiment Common to First, Third, Fifth and Sixth Viewpoints" except for the points mentioned below.

[0441] like Figures 39-40 As shown, the container body 2 has an opening 5, a body 6, and a bottom 7. Figure 41 As shown, the container body 2 has an inner bag 4 and an outer shell 3 configured to cover the inner bag 4. The description of the inner diameter D2 of the opening 5 of the outer shell 3 and the outer diameter D4 of the opening 5 of the outer shell 3 is the same as that of the eighth viewpoint.

[0442] <Interlocking structure between mouth mounting component 8 and container body 2>

[0443] The preferred mouth mounting member 8 is configured to be mounted on the mouth 5, and is configured such that the inner bag 4 rotates within the mouth 5 as the mouth mounting member 8 rotates (in this case, relative to the outer shell 3). With this configuration, the inner bag 4 can be rotated within the mouth 5 by rotating the mouth mounting member 8. In this embodiment, the container body 2 moves the inner bag 4 in a direction that allows it to be pulled out of the outer shell 3 by rotating the inner bag 4 relative to the outer shell 3. Therefore, by rotating the mouth mounting member 8, the inner bag 4 can be raised from the outer shell 3. Then, taking advantage of the portion of the inner bag 4 that has risen from the outer shell 3, the inner bag 4 can be easily pulled out of the outer shell 3.

[0444] In addition, the outer diameter of the body 6 of the container body 2 is larger than that of the opening 5. Therefore, it is difficult to pull the inner bag 4 through the opening 5 of the outer shell 3 by simply stretching the inner bag 4. However, by rotating the opening 5 of the inner bag 4, the inner bag 4 is twisted, and the body 6 of the inner bag 4 is narrowed. This makes it easier for the body 6 of the inner bag 4 to pass through the opening 5 of the outer shell 3, and the inner bag 4 can be easily pulled out of the outer shell 3.

[0445] The following describes in more detail the engagement structure between the mouth mounting component 8 and the container body 2.

[0446] like Figure 42 As shown, the inner bag 4 has a protrusion 4c that protrudes from the opening end 3a of the outer shell 3. The protrusion 4c has a protruding tube 4c1, a locking protrusion 4c2, and an abutting flange 4c4.

[0447] The engaging protrusion 4c2 protrudes radially outward from the circumference of the protruding cylinder 4c1. The engaging protrusion 4c2 is circumferentially separated and provided at multiple locations (eight locations in this embodiment). A conical surface 4c6 is provided on the upper surface of the engaging protrusion 4c2. Thus, as described later, the annular protrusion 28c of the mouth mounting member 8 ( Figure 44A (As shown in the middle diagram) it becomes easier to cross the locking protrusion 4c2.

[0448] The abutting flange 4c4 is an annular portion located at the position abutting the open end 3a and having a larger diameter than the protruding cylinder 4c1. By abutting the open end 3a with the abutting flange 4c4, the inner bag 4 is prevented from falling into the outer shell 3. Alternatively, the abutting flange 4c4 may not be provided, and the inner bag 4 may be prevented from falling into the outer shell 3 by abutting the opening end 3a with the locking protrusion 4c2.

[0449] An annular protrusion 5a2 and intermittently engaging protrusions 3k are provided on the outer peripheral surface of the opening 5 of the outer casing 3. The engaging protrusions 3k are provided at multiple locations (8 locations in this embodiment) on the annular protrusion 5a2 in a circumferentially separated manner.

[0450] like Figure 44A as well as Figure 44B As shown, the mouth mounting member 8 is a pressure cap type. By applying an axial force (perpendicular to the opening surface 5c1 surrounded by the opening end 5c of the mouth 5) to the mouth mounting member 8, the mouth mounting member 8 can be installed on the mouth 5.

[0451] The opening mounting member 8 has a main body 28 and a strap 29. The main body 28 and the strap 29 are connected to each other via a tear-resistant connecting part 30. The strap 29 engages with the opening 5 of the outer casing 3 in both the circumferential and axial directions. Therefore, the movement of the strap 29 relative to the opening 5 of the outer casing 3 in both the circumferential and axial directions is restricted. The main body 28 engages with the opening 5 of the inner bag 4 in both the circumferential and axial directions. Therefore, the movement of the main body 28 relative to the opening 5 of the inner bag 4 in both the circumferential and axial directions is restricted.

[0452] The connecting portion 30 is configured to be tearable by applying force (shear force, force in the rotational direction, etc.) between the main body portion 28 and the belt portion 29. Preferably, the wall thickness of the connecting portion 30 is thinner than that of the main body portion 28 and the belt portion 29. Preferably, the connecting portion 30 is separated in the circumferential direction and provided at multiple locations. As a result, tearing becomes easier.

[0453] The belt portion 29 is strip-shaped and configured to surround the annular protrusion 5a2. An engaging protrusion 29a extending circumferentially and an engaging recess 29b located closer to the connecting portion 30 than the engaging protrusion 29a are provided on the inner circumferential surface of the belt portion 29. The engaging recess 29b is circumferentially separated and provided at multiple locations (eight locations in this embodiment). The belt portion 29 engages axially with the opening 5 of the housing 3 by engaging the annular protrusion 5a2 with the engaging protrusion 29a. A tapered surface 29a1 is provided on the lower side of the engaging protrusion 29a to reduce the force required for the engaging protrusion 29a to cross the annular protrusion 5a2.

[0454] In addition, such as Figure 46BAs shown, the engaging protrusion 3k is accommodated within the engaging recess 29b, thereby engaging the strap 29 with the opening 5 of the outer casing 3 in the circumferential direction. As will be described later, the double container 1 of this embodiment is configured such that, by rotating the opening mounting member 8 and the inner bag 4 as a single unit, the inner bag 4 moves in the direction of being pulled out from the outer casing 3. This may cause the following problem: if the opening mounting member 8 is unintentionally rotated relative to the outer casing 3, the inner bag 4 may be unintentionally pulled out from the outer casing 3. To prevent such a problem, the strap 29 of the opening mounting member 8 is engaged with the opening 5 of the outer casing 3 in the circumferential direction, suppressing rotation of the opening mounting member 8 relative to the opening 5 of the outer casing 3.

[0455] A slit 29c is provided in the belt portion 29. By holding one end of the belt portion 29 and pulling it radially outward in the slit 29c, the connecting portion 30 can be torn and the belt portion 29 can be removed. In addition, a handle can be provided at one end of the belt portion 29 for easy gripping.

[0456] The main body 28 has an outer cylinder 28a, an inner cylinder 28b, an annular protrusion 28c, a locking protrusion 28d, a top plate 28e, and a discharge port 28f.

[0457] A top plate 28e is disposed on the upper surface of the outer cylinder 28a. A nozzle 28f is disposed on the top plate 28e. A nozzle may also be disposed on the nozzle 28f. The inner cylinder 28b is a so-called inner ring, which is smaller in diameter than the outer cylinder 28a and is disposed inside the outer cylinder 28a.

[0458] The annular protrusion 28c is an annular protrusion extending circumferentially on the inner circumferential surface of the outer cylinder 28a. The main body 28 engages axially with the opening 5 of the inner bag 4 via the annular protrusion 28c and the engaging protrusion 4c2. The engaging protrusion 28d is circumferentially separated and provided at multiple locations (eight locations in this embodiment). Figure 46A As shown, the engaging protrusion 28d is disposed between adjacent engaging protrusions 4c2, thereby engaging the main body 28 with the opening 5 of the inner bag 4 in the circumferential direction.

[0459] <The locking structure between the outer shell 3 and the inner pocket 4>

[0460] like Figure 42 As shown, a cam protrusion 4g and an engaging protrusion 4h are provided on the outer peripheral surface of the inner bag 4. The cam protrusion 4g and the engaging protrusion 4h are connected to each other. When viewed from the opening end 5c side of the opening 5, the lower surfaces of the cam protrusion 4g and the engaging protrusion 4h are respectively inclined in a manner that they get closer to the opening end 5c as the movement proceeds in a clockwise direction.

[0461] like Figure 43As shown, a cam track 3l and a locking recess 3m are provided on the inner circumferential surface of the outer casing 3. The locking recess 3m is configured such that its lower surface is continuous with the upper surface of the cam track 3l. Viewed from the opening end 3a side, the upper surface of the cam track 3l and the lower surface of the locking recess 3m are inclined such that they move closer to the opening end 3a as the movement proceeds clockwise. In the state before the inner bag 4 is pulled out from the outer casing 3, the locking protrusion 4h is disposed in the locking recess 3m, and the lower surface of the cam protrusion 4g abuts against the upper surface of the cam track 3l. The cam protrusion 4g and the cam track 3l constitute a cam mechanism 31. In this embodiment, the locking recess 3m is a through hole, but it can also be a non-through hole.

[0462] <How to remove inner pocket 4>

[0463] Before the inner bag 4 is removed, the main body 28 of the opening mounting member 8 is connected to the strap 29, and the strap 29 is axially engaged with the opening 5 of the outer casing 3. Therefore, in this state, the inner bag 4 cannot be removed from the outer casing 3. Therefore, firstly, one end of the strap 29 is grasped at the cut portion 29c and pulled radially outward, thereby tearing the connecting portion 30 and removing the strap 29. This releases the engagement between the opening mounting member 8 and the opening 5 of the outer casing 3, allowing the inner bag 4 to be removed.

[0464] Next, viewed from the opening end 5c, the mouth mounting member 8 is rotated clockwise. The inner bag 4 engages with the mouth mounting member 8 in the circumferential direction; therefore, as the mouth mounting member 8 rotates, the inner bag 4 also rotates in the same direction. The cam protrusion 4g moves along the cam track 3l, and with this movement, the inner bag 4 moves in the direction of being pulled out from the outer casing 3. At this time, the inner bag 4 is twisted, and the body 6 of the inner bag 4 narrows. Furthermore, viewed from the opening end 5c, if the inner bag 4 is rotated counterclockwise, it will... Figure 46B As shown, the cam protrusion 4g of the inner bag 4 interferes with the protrusion 3l1 that constitutes the cam track 3l, making it impossible to rotate the inner bag 4. Therefore, this prevents the incorrect direction of rotation of the inner bag 4.

[0465] Then, the opening mounting member 8 is moved axially to pull the inner bag 4 out of the outer shell 3. The opening mounting member 8 engages axially with the inner bag 4, so the axial force applied to the opening mounting member 8 is transmitted to the inner bag 4, thereby pulling the inner bag 4 out of the outer shell 3. This pulling out is performed with the inner bag 4 raised from the outer shell 3, thus reducing the force required to pull out the inner bag 4.

[0466] 1-2. Method for manufacturing double container 1

[0467] like Figures 47-48As shown, the container body 2 can be manufactured in the same manner as described in "1. First Embodiment Common to First, Third, Fifth and Sixth Viewpoints" except for the following points.

[0468] <Structure of inner preform 14, outer preform 13, and preform 15>

[0469] like Figure 47 As shown, the inner preform 14 is a bottomed cylindrical part, having an opening 14a, a body 14b, and a bottom 14c. A cam protrusion 14g and a locking protrusion 14h, which serve as a cam protrusion 4g and a locking protrusion 4h, are provided on the outer peripheral surface of the opening 14a of the inner preform 14.

[0470] like Figure 47 As shown, the outer preform 13 is a bottomed cylindrical part, having an opening 13a, a body 13b, and a bottom 13c. The bottom 13c is configured to close the lower end of the body 13b. An annular protrusion 13d and a positioning hole (not shown) are provided on the bottom 13c. The opening 13a of the outer preform 13 has a cam track 13l that serves as a cam track 3l and an engaging recess 13m that serves as an engaging recess 3m.

[0471] like Figure 48 As shown, when forming the preform 15, the protrusion 14d abuts against the open end of the mouth 13a, and the positioning pin 14c1 is inserted into the positioning hole.

[0472] <The inner preform 14 and the outer preform 13 engage at the opening 15a>

[0473] In this embodiment, such as Figure 47 As shown, the engagement is the engagement of an engagement protrusion 14h provided on the outer peripheral surface of the opening 14a of the inner preform 14 and an engagement recess 13m provided on the inner surface of the opening 13a of the outer preform 13. The engagement protrusion 14h and the engagement recess 13m are respectively called engagement protrusion 4h and engagement recess 3m.

[0474] 2. Other implementation methods

[0475] It is not necessary for the mouth mounting component 8 to engage with the inner bag 4. Alternatively, the inner bag 4 can be directly held to rotate or be pulled out.

[0476] As the cam mechanism 31, any mechanism capable of changing the relative rotation between the inner bag 4 and the outer shell 3 into the axial movement of the inner bag 4 can be adopted.

[0477] (Tenth viewpoint)

[0478] use Figures 28A to 38The tenth aspect of the present invention will be described in the following description.

[0479] 1. First Implementation Method

[0480] 1-1. Structure of Double Container 1

[0481] <Basic Structure>

[0482] The descriptions of the container body 2 and the mouth mounting component 8 are the same as those described in the eighth point, except for the points mentioned below.

[0483] The container body 2 is a biaxially extended blow-molded body formed by biaxial extension blow molding, and the inner bag 4 and the outer shell 3 are formed by biaxial extension blow molding. Details of biaxial extension blow molding are described later. In the biaxially extended blow-molded body, it is difficult to increase the tightness between the inner bag 4 and the outer shell 3. Therefore, compared with the direct blow-molded body of the molten preform, the force required to pull the inner bag 4 out of the outer shell 3 is reduced.

[0484] <Materials, Layer Structure>

[0485] Preferably, the inner bag 4 has an EVOH layer. The EVOH layer is a layer composed of an EVOH-type resin containing 50% by mass or more of EVOH (ethylene-vinyl alcohol copolymer). The EVOH-type resin may contain only EVOH or may be a mixture of EVOH and other resins. Examples of other resins include olefin resins. An olefin resin is a resin in which the olefin units constitute 50% by mass or more. Examples of olefins include ethylene and propylene. The proportion of olefin units in the olefin resin is, for example, 50 to 100% by mass, specifically, for example, 50, 60, 70, 80, 90, or 100% by mass, or within any two of the values ​​exemplified here, or any value or more. Examples of olefin resins include low-density polyethylene, linear low-density polyethylene, high-density polyethylene, polypropylene, and copolymers (random copolymers or block copolymers) of propylene and other olefins (such as ethylene). The proportion of EVOH in EVOH-type resins is, for example, 50 to 100% by mass, specifically, for example, 50, 60, 70, 80, 90, or 100% by mass, or it can be within the range of any two values ​​exemplified here or any value above any value.

[0486] Preferably, the ethylene content in the EVOH contained in the EVOH layer is 32-46 mol%. The presence of an EVOH layer in the inner bag 4 improves its gas barrier properties. If the ethylene content of the EVOH is too low, the softness of the inner bag 4 decreases significantly, and its pull-out properties deteriorate considerably. Furthermore, as described later, if the ethylene content of the EVOH is too low, the inner bag 4 becomes too brittle. Figure 28A as well as Figure 28B As shown, when the opening mounting member 8 engages with the protrusion 4c of the inner bag 4, cracking may occur at the protrusion 4c. On the other hand, if the ethylene content of EVOH is too high, the improvement in the gas barrier properties of the inner bag 4 may become insufficient. By keeping the ethylene content within the aforementioned range, the occurrence of the above problems can be suppressed. Specifically, the ethylene content can be, for example, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, or 46 mol%, or it can be within the range of any two values ​​exemplified here.

[0487] The inner bag 4 can be a single-layer structure with EVOH layers, or a multi-layer structure with multiple EVOH layers. In the case where the inner bag 4 is a single-layer structure with EVOH layers, the inner preform 14 used to form the inner bag 4... Figure 36 (As shown in the diagram) It can also be a single-layer structure. The single-layer inner preform 14 can be formed by general injection molding, thus reducing manufacturing costs. When the inner bag 4 is a multi-layer structure, other layers are provided on one or both of the inner and outer surface sides of the EVOH layer. As other layers, olefin resin layers made of olefin resins can be cited. The description of olefin resins is as described above. Regarding the layer structure of the inner bag 4, specifically, starting from the outer surface side, outer surface layer / EVOH layer, EVOH layer / inner surface layer, and outer surface layer / EVOH layer / inner surface layer can be cited. The outer surface layer and the inner surface layer are the other layers mentioned above, and these layers can be single-layer or multi-layer structures. It is particularly preferred that the outer surface layer and the inner surface layer are polypropylene layers.

[0488] When the adhesion between the EVOH layer and other layers is not good, an adhesive resin layer can be placed between the EVOH layer and other layers, and / or an adhesive resin can be formulated into one or both of the EVOH layer and other layers. The adhesive resin is a resin that exhibits good adhesion to both the EVOH layer and other layers; examples include acid-modified polyolefin resins (such as maleic anhydride-modified polyethylene and maleic anhydride-modified polypropylene).

[0489] The EVOH layer may or may not be exposed on the inner surface of the inner bag 4. When the EVOH layer is exposed on the inner surface of the inner bag 4, it absorbs moisture from the contents and softens, thus making it easier to remove the inner bag 4. Furthermore, EVOH is less likely to absorb citrus-based flavor components; therefore, when the contents contain citrus-based flavor components, using the EVOH layer as the innermost layer of the inner bag 4 can suppress flavor degradation. When the EVOH layer is not exposed on the inner surface of the inner bag 4, its gas barrier properties decrease slightly due to moisture absorption. However, the higher the ethylene content of the EVOH, the smaller the decrease in gas barrier properties caused by moisture absorption. Therefore, the advantage of improved softness outweighs the disadvantage of decreased gas barrier properties. On the other hand, when the EVOH layer is not exposed on the inner surface of the inner bag 4, the absorption of moisture from the contents by the EVOH layer is suppressed, thus preventing a decrease in the gas barrier properties of the EVOH layer.

[0490] The material and layer structure of the outer shell 3 are not particularly limited. The outer shell 3 can be formed from thermoplastic resins such as polyester (e.g., PET) or polyolefins (e.g., polypropylene, polyethylene). From the viewpoint of recyclability, it is preferred to form it from PET. In addition, from the viewpoint of reducing environmental impact, it is preferred that the outer shell 3 be formed from biomass plastics.

[0491] 1-2. Method for manufacturing double container 1

[0492] <Materials and manufacturing methods of inner preform 14 and outer preform 13>

[0493] The inner preform 14 can be used to form the inner bag 4 from the aforementioned materials. The inner preform 14 can be formed by direct blow molding or injection molding, but from the viewpoint of manufacturing cost, injection molding is preferred. A multi-layered inner bag 4 can be formed using the multi-layered inner preform 14. The multi-layered inner preform 14 can be formed by two-color molding or co-injection molding.

[0494] The outer preform 13 can form the outer shell 3 using the aforementioned material. The outer preform 13 can be formed by direct blow molding or injection molding, but from the viewpoint of manufacturing cost, it is preferred to form it by injection molding.

[0495] The preform 15 can be formed by combining the inner preform 14 and the outer preform 13 after they are formed separately, or it can be formed by two-color molding.

[0496] (Example of the tenth viewpoint)

[0497] 1. Manufacturing of container body 2

[0498] <Example 1>

[0499] Based on the above method, by... Figures 36-38 The preform 15 shown is subjected to biaxial stretch blow molding to produce Figure 28A as well as Figure 28B The container body 2 shown has a capacity of 300 mL. The inner preform 14 is manufactured by injection molding EVOH (ethylene content 38 mol%, model: GSoarnol GH3804B, manufactured by Mitsubishi Chemical Corporation) at 250°C. The outer preform 13 is manufactured by injection molding PET (model: titanium catalyst grade, manufactured by Teijin Corporation) at 300°C to form the shape of the outer preform, followed by rapid cooling to 20°C. Rapid cooling transforms the molten PET into an amorphous state.

[0500] After heating such a preform 15 to 110°C (the temperature at the center of the preform 15 along its length), biaxial stretch blow molding is performed to obtain the container body 2.

[0501] <Comparative Example 1>

[0502] Except for the material used to form the inner preform 14, which is EVOH (ethylene content 29 mol%, model: Soarnol D2908, manufactured by Mitsubishi Chemical Corporation), the container body 2 was obtained in the same manner as in Example 1.

[0503] 2. Experiment

[0504] Crack resistance and pull-out tests were conducted on the container body 2 of Example 1 and Comparative Example 1. The results for both the crack resistance and pull-out tests of the container body 2 of Example 1 were ○. On the other hand, the results for both the crack resistance and pull-out tests of the container body 2 of Comparative Example 1 were ×.

[0505] Specifically, the crack resistance test and pull-out test are carried out by the following methods.

[0506] <Crack Resistance Test>

[0507] In use Figure 28A as well as Figure 28B The following criteria are used to evaluate whether cracking occurs at the engagement protrusion 4c2 due to the claw portion 8e of the mouth mounting member 8 when it engages with the mouth portion 5 of the container body 2.

[0508] ○: No cracks have occurred.

[0509] ×: Cracks have formed.

[0510] <Pull-out test>

[0511] After water is contained in the inner bag 4 of the container body 2, the mouth mounting member 8 is installed on the mouth 5 and engaged with the inner bag 4. The container is then left to stand for one day. Then, all water is drained from the inner bag 4. Next, the mouth mounting member 8 is rotated in the loosening direction to release the engagement with the mouth 5. Then, the mouth mounting member 8 is pulled to remove the inner bag 4 from the container body 2. The pull-out strength is measured and evaluated using the following criteria.

[0512] ○: Pull-out strength is less than 3 kgf.

[0513] ×: Pull-out strength is above 3 kgf.

[0514] Explanation of reference numerals in the attached figures

[0515] 1: Double container; 2: Container body; 3: Outer shell; 3a: Open end; 3b: Annular protrusion; 3c: Through hole; 3f: Recess; 3f1: Groove; 3f2: End; 3f3: End; 3g: Protrusion; 3h: Protrusion; 3i: Protrusion; 3k: Engaging protrusion; 3l: Cam track; 3l1: Protrusion; 3m: Engaging recess; 3n: Insertion part; 3o: Conical surface; 4: Inner bag; 4b: Flange; 4c: Protrusion; 4c1: Protruding cylinder; 4c2: Engaging protrusion; 4c3: Engaging flange; 4c4: Abutting flange; 4c5: Circumferential inclined surface; 4c6: Conical surface; 4d: Side; 4e: Protrusion; 4f: Protrusion; 4f1: Conical surface; 4g: Cam protrusion; 4h: Engaging protrusion; 4n: Flange; 4n1: 4o: Opening end; 5: Mouth; 5a: Engaging part; 5a1: External thread part; 5a2: Annular protrusion; 5b: Flange; 5c: Opening end; 5c1: Opening surface; 6: Body; 6a: Upper end; 6b: Shoulder; 6c: Main body; 6d: Recess; 6e: Groove; 6f: Bend; 6f1: Part; 6g: Reduced diameter; 7: Bottom; 7a: Bottom recessed area; 7a1: Circumferential surface; 7a2: Bottom surface; 7b: Peripheral area; 8: Mouth mounting component; 8a: Outer cylinder; 8b: Intermediate cylinder; 8c: Inner cylinder; 8d: Engaging part; 8d1: Internal thread part; 8e: Claw; 8e1: Upper surface; 8e2: Lower inclined surface; 8f: Top plate; 8g: Nozzle; 8h: Through hole; 8i: Protrusion; 8j: Spray 9: Mouth, 9a: Concave strip, 9b: Convex strip, 10: Alternating wall thickness shape, 10a: Thin-walled part, 10b: Thick-walled part, 11: Concave strip, 13: Outer preform, 13a: Mouth, 13b: Body, 13c: Bottom, 13c2: Positioning hole, 13c4: Annular convex part, 13d: Annular convex part, 13f: Concave part, 13g: Slit, 13h: Protrusion, 13i: Protrusion, 13j: Opening end, 13k: Positioning hole, 13l: Cam track, 13m: Engaging concave part, 14: Inner preform, 14a: Mouth, 14a1: Flange, 14b: Body, 14c: Bottom, 14c1: Positioning pin, 14d: Protrusion, 14f: Convex part, 14f1: Conical surface, 14f2: Conical surface 14g: Cam protrusion, 14h: Engaging protrusion, 14i: Flange, 15: Preform, 15a: Mouth, 15b: Body, 15c: Bottom, 15d: Extended portion, 16: External gas inlet hole, 17: Through hole, 19: Concave-convex shape, 20: Alternating wall thickness shape, 20a: Thin-walled portion, 20b: Thick-walled portion, 21: Recessed strip, 22: Information transmission display, 22a: Recycling mark, 22b: Message, 23: Information transmission display, 23a: Recycling mark, 23b: Message, 24: Anti-loosening structure, 25: Support rod, 26: Ventilation passage, 28: Main body, 28a: Outer cylinder, 28b: Inner cylinder, 28c: Annular protrusion, 28d: Engaging protrusion, 28e: Top plate, 28f: Nozzle29: Belt section; 29a: Engaging convex part; 29a1: Conical surface; 29b: Engaging concave part; 29c: Cutout part; 30: Connecting part; 31: Cam mechanism; 33: Concave-convex shape; 33a: Convex part; 33b: Concave part; 34: Concave-convex shape; 34a: Convex part; 34b: Concave part; 35: Concave-convex shape; 36: Easy-to-expand diameter part; 37: Slit; 38: Diameter expansion suppression part; 39: Gap; 40: Manufacturing device; 44 : Concave-convex shape, 45: Concave-convex shape, 50: Mold unit, 51: Mouth support mold, 51a: Through hole, 52: Bottom support mold, 52a: Recess, 52b: Recess, 52c: Drive mechanism, 53: Forming mold, 53a: Cavity surface, 54: Forming mold, 54a: Cavity surface, 61: Heater, A: Surface, C: Central axis, D2: Inner diameter, D4: Outer diameter, R: Radius of curvature, α: Inclination angle.

Claims

1. A dual container having a container main body and a mouth portion mounting member, wherein the container main body has a mouth portion, a body portion, and a bottom portion, the mouth portion is a cylindrical portion having an open end, the body portion is disposed adjacent to the mouth portion on a side farther from the open end than the mouth portion, and an outer diameter of the body portion is larger than an outer diameter of the mouth portion, the bottom portion is configured to close a lower end of the body portion, the container main body has an inner bag and an outer shell disposed so as to cover the inner bag, the mouth portion mounting member is configured to be mountable to the mouth portion, and the inner bag is configured to rotate with rotation of the mouth portion mounting member, the inner bag has a protruding portion protruding from the open end of the outer shell, the protruding portion has a protruding cylinder and an engagement protrusion protruding from a peripheral surface of the protruding cylinder toward a radially outer side, the engagement protrusion is configured to engage with a claw portion of the mouth portion mounting member in a direction of rotation of the mouth portion mounting member, whereby the inner bag rotates with rotation of the mouth portion mounting member, the protruding portion has an engagement flange at a position farther from the open end than the engagement protrusion, the engagement flange engages with the claw portion of the mouth portion mounting member in an axial direction of the mouth portion, whereby the inner bag is pulled out of the outer shell as the mouth portion mounting member is moved in a direction away from the open end.

2. The dual container according to claim 1, wherein the protruding portion has an abutment flange that abuts against the open end, and the engagement protrusion is disposed between the abutment flange and the engagement flange.

3. The dual container according to claim 1 or 2, wherein a concavo-convex shape in which concave lines and convex lines appear alternately in a circumferential direction of the mouth portion is provided on an inner surface of at least one of the mouth portion and a position of the body portion adjacent to the mouth portion, and the concave lines and the convex lines extend non-parallelly in the circumferential direction of the mouth portion.

4. A dual container having a container main body, wherein the container main body has a mouth portion, a body portion, and a bottom portion, the mouth portion is a cylindrical portion having an open end, the body portion is disposed adjacent to the mouth portion on a side farther from the open end than the mouth portion, and an outer diameter of the body portion is larger than an outer diameter of the mouth portion, the bottom portion is configured to close a lower end of the body portion, the container main body has an inner bag and an outer shell disposed so as to cover the inner bag, a concavo-convex shape in which concave lines and convex lines appear alternately in a circumferential direction of the mouth portion is provided on at least one of the mouth portion and a position of the body portion adjacent to the mouth portion, the concave lines and the convex lines extend non-parallelly in the circumferential direction of the mouth portion, and the concavo-convex shape is provided on an inner surface of the inner bag.

5. The dual container according to claim 4, wherein the concavo-convex shape is formed by reducing a wall thickness of the concave lines as compared to a wall thickness of other portions of the mouth portion of the inner bag. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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