Double container and method for manufacturing same, and method for pulling out inner bag from double container

Abstract

Provided is a double container capable of reducing the time and effort required to manufacture the double container and / or the number of components thereof.　The present invention provides a double container comprising a container body and a mouth portion attachment member, wherein: the container body comprises an inner bag and an outer shell disposed so as to cover the inner bag; the mouth portion attachment member is attached to a mouth portion of the container body; the double container is provided with an air flow regulating portion; the air flow regulating portion regulates the flow of air between the external space of the container body and an intermediate space between the inner bag and the outer shell; and the air flow regulating portion is configured to regulate the flow of air through a gap between the outer shell and the mouth portion attachment member. The double container of the present invention has excellent recyclability, and can therefore be suitably used in the production of recycled materials.

Description

Double container, method for manufacturing the same, and method for withdrawing inner bag from double container

[0001] The present invention relates to a double container, a method for manufacturing the same, and a method for withdrawing an inner bag from the double container.

[0002] (First aspect) Patent Document 1 discloses a method for manufacturing a double container by biaxial stretch blow molding.

[0003] (Second aspect) Patent Document 2 discloses a double container in which a cap is attached to a container body. In this document, the cap includes a cap body (inner stopper) attached to the inner bag of the double container and an overcap attached to the cap body. The cap body is circumferentially engaged with the inner bag of the double container, and is configured such that the inner bag can be twisted and its diameter reduced by gripping and rotating the cap body.

[0004] WO2022 / 215598WO2024 / 024715

[0005] (First aspect) In the double container of Patent Document 1, an outside air introduction hole is provided in the container body, and a check valve is engaged and attached to this outside air introduction hole, whereby the compressive force applied to the outer shell is transmitted to the inner bag, and the outer shell is configured to restore to its original shape when the compressive force is removed.

[0006] In the configuration of Patent Document 1, since the steps of forming the outside air introduction hole and engaging the check valve are essential, it is difficult to reduce the labor and the number of parts required for manufacturing the double container.

[0007] The present invention has been made in view of such circumstances, and provides a double container capable of reducing at least one of the labor and the number of parts required for manufacturing the double container.

[0008] (Second aspect) In a double container such as Patent Document 2, the rotation direction of the overcap when removing the overcap and the rotation direction of the cap body when twisting and reducing the diameter of the inner bag are the same, and there is a risk of accidentally rotating the cap body when trying to remove the overcap and unintentionally reducing the diameter of the inner bag.

[0009] This invention has been made in view of these circumstances, and provides a double-walled container that can prevent the cap body from being unintentionally rotated when attempting to remove the overcap.

[0010] (First Perspective) The present disclosure provides the following inventions: [1] A double container comprising a container body and a mouth attachment member, wherein the container body comprises an inner bag and an outer shell disposed to cover the inner bag, the mouth attachment member is attached to the mouth of the container body, the double container is provided with an air flow restricting portion, the air flow restricting portion restricts the air flow between the external space of the container body and the intermediate space between the inner bag and the outer shell, and the air flow restricting portion is configured to restrict the air flow through the gap between the outer shell and the mouth attachment member. [2] The double container according to [1], wherein the air flow restricting portion is configured to suppress the leakage of air from the intermediate space when the outer shell is compressed, and to allow the inflow of air from the external space to the intermediate space when the compression of the outer shell is released. [3] A double container according to [1] or [2], wherein the mouth attachment member is attached to a protruding portion of the inner bag that protrudes from the opening end of the outer shell. [4] A double container according to any one of [1] to [3], wherein the intermediate space and the outer space are in communication via the air flow restricting portion through a gap between the opening end of the outer shell and the inner bag. [5] A double container according to any one of [1] to [4], wherein the air flow restricting portion comprises a valve body and a contact portion, the valve body is provided on the mouth attachment member, the contact portion is provided on the outer shell, and the flow of air through the air flow restricting portion is suppressed by the contact between the valve body and the contact portion, and the flow of air through the air flow restricting portion is permitted by the gap provided between the valve body and the contact portion. A double container according to [6] [5], wherein the mouth attachment member comprises a cap body that can engage with the inner bag, the valve body is provided so as to protrude from the cap body toward the outer shell, the outer shell comprises an annular projection, the valve body is positioned radially inward of the annular projection, and the contact portion is provided on the inner circumferential surface of the annular projection. A double container according to [7] [6], wherein the tip of the valve body is spaced apart from the outer shell.A double container according to [8] [5], wherein the mouth attachment member comprises a cap body that can engage with the inner bag, and the valve body is provided so as to protrude radially inward from the cap body. A double container according to [9] [8], wherein the outer shell comprises an annular projection, and the contact portion is provided on the annular projection. A method for manufacturing a double container according to any one of [1] to [9], wherein the container body is formed by biaxial stretch blow molding of a preform.

[0011] (Second viewpoint) The present invention provides the following inventions: [1] A double container comprising a container body and a cap, wherein the container body comprises an inner bag and an outer shell disposed to cover the inner bag, the cap is attached to the mouth of the container body, the cap comprises a cap body attached to the container body and an overcap attached to the cap body, the cap body engages with the inner bag in the circumferential direction, the cap body has an anti-slip shape on its outer surface, and at least a part of the anti-slip shape is a first anti-slip shape provided in a first region that is covered by the overcap when the overcap is attached, a double container. [2] The double container according to [1], wherein the anti-slip shape includes a second anti-slip shape provided in a second region that is not covered by the overcap when the overcap is attached, a double container. [3] The double container according to [2], wherein the outer diameter of the portion where the second region is provided is larger than the outer diameter of the portion where the first region is provided. A double-walled container according to [4], [2], or [3], wherein the region provided with the second anti-slip shape has an axial length of 1.0 mm to 6.0 mm. A double-walled container according to any one of [5], [2] to [4], wherein the overcap has a third anti-slip shape on its outer circumferential surface, and the distance from the lower end of the overcap to the third region provided with the third anti-slip shape is 3.0 to 10.0 mm. A double-walled container according to any one of [6], [1] to [5], wherein the rotation direction of the overcap when removing the overcap coincides with the rotation direction of the cap body when twisting the inner bag to reduce its diameter. A double-walled container according to any one of [7], [1] to [6], wherein the first anti-slip shape does not engage with the overcap in the circumferential direction.[8] A method for removing an inner bag from a double container, wherein the double container is the double container described in any one of [1] to [7], and the method comprises a diameter reduction step and a removal step, wherein in the diameter reduction step, the inner bag is twisted and reduced in diameter by gripping and rotating the cap body in a first region with the overcap removed, and in the removal step, the reduced-diameter inner bag is removed from the container body. [9] A method for manufacturing a double container described in any one of [1] to [7], wherein the container body is formed by biaxial stretch blow molding of a preform.

[0012] (First viewpoint) The airflow restricting section of the double-walled container of the present invention restricts the airflow through the gap between the outer shell and the mouth attachment member, so it can be configured to introduce air into the intermediate space through the gap between the outer shell and the inner bag. For this reason, the process of forming an outside air intake hole can be omitted, and the effort required to manufacture the double-walled container can be reduced. Furthermore, since the airflow restricting section can be composed of the mouth attachment member and the outer shell, it is not essential to provide additional members such as the check valve in Patent Document 1, so the number of parts required to manufacture the double-walled container can be reduced.

[0013] (Second viewpoint) In the double-walled container of the present invention, at least a portion of the anti-slip shape provided on the cap body is a first anti-slip shape provided on the first portion that is covered by the overcap when the overcap is attached, so that it is difficult to rotate the cap body when the overcap is attached. For this reason, it is possible to prevent the cap body from being rotated unintentionally when trying to remove the overcap.

[0014] (First Aspect) This is a perspective view of a double-walled container 1 according to the first embodiment of the first aspect of the present invention. The dashed lines in the figure represent boundary lines where the curvature of the surfaces constituting the surface shape changes. The same applies to the other figures. This is an exploded perspective view of the double-walled container 1 in Figure 1. Figures 3A and 3B are a plan view and a front view of the container body 2 in Figure 2, respectively. Figure 4A is a longitudinal cross-sectional view of the double-walled container 1 in Figure 1 with the overcap 42 closed. Figure 4B is an enlarged view of area B in Figure 4A. This is an exploded view of Figure 4A with the overcap 42 slightly open. Figure 6A is an enlarged view of area A in Figure 5. Figure 6B is a figure corresponding to Figure 6A in the reference example. This is an exploded view of the container body 2 in Figure 5. Figure 8A is a cross-sectional view taken along A-A in Figure 5. Figure 8B is an enlarged view of area B in Figure 8A. This is a cross-sectional view taken along B-B in Figure 5. Figure 10A is a cross-sectional view taken along C-C in Figure 5. Figure 10B is an enlarged view of area C in Figure 10A. Figure 10C is an enlarged view of area D in Figure 10B. This is an exploded perspective view of the container body 2 in Figure 2. Figure 12A is a front view of the inner bag 4. Figure 12B is a cross-sectional view taken along line D-D in Figure 12A. Figure 13A is a cross-sectional view of the container body 2 immediately after the pressure on the body portion 6 has been released. Figure 13B is an enlarged view of area E in Figure 13A. This is a perspective view showing the inner preform 14 and outer preform 13 separated. This is a perspective view of the preform 15 formed by placing the outer preform 13 over the inner preform 14. This is a front view showing the inner preform 14 supported by a pair of rails 45. This is a longitudinal cross-sectional view of the preform 15. This is an enlarged view corresponding to Figure 4B of the second embodiment. This is an enlarged view showing the state when the valve body 41e is displaced away from the contact portion 3i. (Second viewpoint) This is a perspective view of the double-walled container 1 of the first embodiment of the second viewpoint of the present invention. This is an exploded view of the double-walled container 1 of Figure 20. This is an exploded view of the vicinity of the mouth portion 5 of the container body 2 of Figure 21. Figure 20 is a longitudinal cross-sectional view of the double-walled container 1. Figure 23 is an exploded view. Figure 25A is a front view of the cap 8a in Figure 21. Figure 25B is an exploded view of Figure 25A. Figure 26A is a perspective view of the cap 8a in Figure 21 from a different direction. Figure 26B is an exploded view of Figure 26A. This is a perspective view showing the inner preform 14 and outer preform 13 separated.This is a perspective view of a preform 15, which is constructed by placing an outer preform 13 over an inner preform 14.

[0015] Embodiments of this disclosure will be described below with reference to the drawings. The various features shown in the embodiments below are combinable with respect to each other. Furthermore, each feature constitutes an invention independently. In addition, any element not specified in the claims of the embodiments below is an optional element and can be omitted. Any number of zeros (e.g., one or two) may be added to the end of the numerical values ​​disclosed in the following description. For example, one or two zeros may be added after "1.4" to make it "1.40" or "1.400". Also, if drawings with sub-numbers (e.g., Figure 1A, Figure 1B) are included, a reference to a drawing without a sub-number (e.g., Figure 1) means a reference to all drawings with sub-numbers (in the above example, Figure 1A and Figure 1B). Furthermore, unless otherwise specified, the numerical values ​​in the following description may be average values.

[0016] (First Perspective) 1. The double-walled container 1 of the first embodiment of the first aspect of the present invention will be described using Figures 1 to 17 of the first embodiment. In the following description, terms relating to directions such as "up" and "down" refer to directions when the bottom 7 is in contact with the ground. In the following description, "axial direction" refers to the direction in which the central axis C (shown in Figure 2) of the opening 5 extends, for example, the direction in which the inner bag 4 is pulled out of the container body 2. "Circumferential direction" refers to the rotational direction around the central axis C of the opening 5, for example, the direction in which the inner bag 4 is rotated relative to the outer shell 3 at the opening 5. "Clockwise" and "counterclockwise" refer to directions viewed from the top of the double-walled container 1 unless otherwise specified.

[0017] 1-1. Configuration of the Double-Walled Container 1 As shown in Figure 1, the double-walled container 1 of this embodiment comprises a container body 2 and a mouth attachment member 8. The double-walled container 1 is, for example, a squeeze-type container. The user of the double-walled container 1 dispenses the contents from the container body 2 by pressing the container body 2. The following describes each component in detail.

[0018] <Configuration of Container Body 2> As shown in Figures 2 to 3, the container body 2 comprises a mouth portion 5, a body portion 6, and a bottom portion 7. The mouth portion 5 is a cylindrical (preferably cylindrical) portion having an open end 5c. The open end 5c is the open end of the container body 2 and is also the open end of the inner bag 4 shown in Figure 5. The mouth portion 5 is provided with an engaging portion 4m to which a mouth portion attachment member 8 can be attached. The engaging portion 4m is provided on a protruding portion 4c of the inner bag 4. As shown in Figures 11 to 12, it comprises an axial engaging portion 4ma that engages with the mouth portion attachment member 8 in the axial direction and a circumferential engaging portion 4mb that engages with the mouth portion attachment member 8 in the circumferential direction. The axial engaging portion 4ma and the circumferential engaging portion 4mb are provided so as to protrude radially outward from the circumferential wall 4b1. A recess is provided on the inner circumferential surface of the axial engaging portion 4ma.

[0019] The body portion 6 is positioned adjacent to the mouth portion 5 on the side further away from the opening end 5c than the mouth portion 5. The body portion 6 has a larger outer diameter than the mouth portion 5 (in this specification, "outer diameter" means the equivalent diameter of a circle if the cross-section is not circular). The body portion 6 is cylindrical, and the bottom portion 7 is provided at the lower end of the body portion 6, closing the lower end of the body portion 6. The body portion 6 has a shoulder portion 6b whose outer diameter increases as it moves away from the mouth portion 5. The body portion 6 also has a body body 6c on the bottom 7 side of the shoulder portion 6b. The body body 6c has a shape in which the outer diameter is substantially constant toward the bottom 7, or a shape in which the diameter decreases toward the bottom 7.

[0020] As shown in Figure 3, the opening 5 comprises an upper opening 5a and a lower opening 5b. The upper opening 5a is the portion between the open end 5c of the container body 2 and the lower surface 5d1 of the flange portion 5d. The lower opening 5b is the portion between the upper opening 5a and the body 6. Below the lower surface 5d1 of the flange portion 5d, the base 5b1 of the lower opening 5b is the portion where the outer diameter of the container body 2 begins to expand.

[0021] The shoulder portion 6b is provided with an uneven surface 6d in which concave ridges 6d1 and convex ridges 6d2 are alternately arranged in the circumferential direction. The convex ridges 6d2 extend in a counterclockwise inclination from the boundary 6e between the shoulder portion 6b and the body portion 6c toward the base 5b1 of the mouth portion 5. The direction in which the convex ridges 6d2 extend coincides with the direction in which the inner bag 4 is rotated when the inner bag 4 is pulled out from the container body 2. In other words, in this embodiment, as will be described later, when the inner bag 4 is pulled out, the inner bag 4 is rotated counterclockwise, so the convex ridges 6d2 are also provided to be inclined counterclockwise. By providing the uneven surface 6d on the shoulder portion 6b, the inner bag 4 is made more likely to fold regularly when it is rotated relative to the outer shell 3, making it easier to reduce the diameter of the inner bag 4.

[0022] The outer surface of the base 5b1 is preferably curved, convex inward. Furthermore, its radius of curvature is preferably 3 mm or more. Setting this radius of curvature to such a value suppresses the inner bag 4 from getting caught on the outer shell 3 at the base 5b1 when the inner bag 4 is pulled out. This radius of curvature is, for example, 3 to 10 mm, preferably 3 to 7 mm, specifically, for example, 3, 4, 5, 6, 7, 8, 9, 10 mm, or within a range between any two of the values ​​exemplified here.

[0023] The main body 6c of the fuselage is provided with a pair of groove-shaped ribs 6f1 and 6f2. The groove-shaped ribs 6f1 and 6f2 extend along the circumferential direction and are spaced apart from each other in the direction of the central axis C. The rigidity of the main body 6c is increased by providing the groove-shaped ribs 6f1 and 6f2.

[0024] As shown in Figures 4 to 8, the container body 2 comprises an inner bag 4 and an outer shell 3 positioned to cover the inner bag 4. As shown in Figure 5, the inner bag 4 has a protruding portion 4c that extends from the open end 3a of the outer shell 3. The mouth attachment member 8 is attached to the protruding portion 4c. The inner bag 4 has an inner bag body 4d, excluding the protruding portion 4c, housed within the outer shell 3. The inner bag 4 is configured to be removable from the container body 2. In Figures 4 and 5, the inner bag 4 and the outer shell 3 are in contact near the mouth 5, but there may be a gap between the inner bag 4 and the outer shell 3 near the mouth 5. In the following description, the parts of the inner bag 4 corresponding to the mouth 5, body 6, and bottom 7 of the container body 2 will be referred to as the mouth 5, body 6, and bottom 7 of the inner bag 4, respectively. The same applies to the outer shell 3.

[0025] <Details of the opening 5 of the inner bag 4> As shown in Figures 8 and 11-12, the inner bag 4 comprises a first cylinder 4a and a second cylinder 4b. The first cylinder 4a is located inside the outer shell 3. The second cylinder 4b has a larger outer diameter than the first cylinder 4a and is located closer to the opening end 5c of the inner bag 4 than the first cylinder 4a. The entire second cylinder 4b may be located outside the outer shell 3, or part or all of the second cylinder 4b may be located inside the outer shell 3 and the rest outside the outer shell 3.

[0026] As shown in Figures 8 and 12, the second cylinder 4b comprises a peripheral wall 4b1 and a lower wall 4b2 provided below the peripheral wall 4b1 and configured to reduce the diameter of the peripheral wall 4b1 toward the first cylinder 4a. The inner bag 4 is positioned such that the lower surface 4b4 of the second cylinder 4b is spaced apart from the outer shell 3. The peripheral wall 4b1 preferably extends parallel to the axial direction. The lower wall 4b2 preferably is positioned inside the outer shell 3.

[0027] The angle α of the peripheral wall 4b1 with respect to the lower wall 4b2 is preferably 90 degrees or more, and more preferably 95 degrees or more. In this case, the bending of the inner bag 4 at the corner 4b3 between the lower wall 4b2 and the peripheral wall 4b1 is relatively gentle, making it less likely to crack when an impact is applied, thus improving impact resistance. This angle α is, for example, 90 to 135 degrees (105 degrees in this embodiment), preferably 95 to 115 degrees, specifically, for example, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135 degrees, and may also be in the range between any two of the values ​​exemplified here.

[0028] The length L1 between the lower surface 4b4 at the corner 4b3 and the lower surface 4m3 of the axial engagement portion 4ma is preferably 2 mm or more. In this case, local bending of the inner bag 4 is further suppressed. The length L1 is, for example, 2 to 10 mm, and preferably 3 to 6 mm (4.2 mm in this embodiment). Specifically, the length L1 is, for example, 2.0, 2.5, 3.0, 3.5, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0 mm, and may be in the range between any two of the values ​​exemplified here. It is preferable that the portion of the peripheral wall 4b1 that is parallel to the axial direction has a length from the lower surface 4b4 within the above numerical range, and it is preferable that it is parallel to the axial direction between the lower surface 4b4 and the lower surface 4m3.

[0029] As shown in Figures 4, 9, and 11-12, the inner bag 4 is provided with a recess 4h in the portion facing the outer shell 3. The recess 4h is formed by recessing the inner bag 4 so that it protrudes inward within the recess 4h. In this embodiment, when the mouth attachment member 8 is attached to the protruding portion 4c, if the rigidity of the protruding portion 4c is insufficient, the rotational force applied to the mouth attachment member 8 may cause the protruding portion 4c to twist, making it difficult to transmit the rotational force to the portion of the inner bag 4 housed within the outer shell 3, and making it difficult to twist the inner bag 4. In the configuration of this embodiment, the recess 4h functions as a rib that reinforces the protruding portion 4c. Therefore, the rotational force applied to the mouth attachment member 8 is more easily transmitted to the portion of the inner bag 4 housed within the outer shell 3, making it easier to twist the inner bag 4.

[0030] Furthermore, in the double-walled container 1 of this embodiment, before attaching the mouth attachment member 8, a leak test of the inner bag 4 may be performed by sucking air from inside the inner bag 4 through the mouth 5 to shrink the inner bag 4. At this time, it is necessary to introduce air into the intermediate space SP1 between the inner bag 4 and the outer shell 3 in order to prevent the outer shell 3 from shrinking together. In this embodiment, if there is no outside air intake hole in the outer shell 3 for introducing air into the intermediate space SP1, the mouth 5 of the inner bag 4 may deform, creating a gap between the inner bag 4 and the outer shell 3 at the mouth 5, and air may be introduced into the intermediate space SP1. Such deformation of the mouth 5 of the inner bag 4 is undesirable as it can lead to defects. In this embodiment, the inner bag 4 is provided with a recess 4h in the part facing the outer shell 3, and air can be introduced into the intermediate space SP1 between the inner bag 4 and the outer shell 3 through the recess 4h, so deformation of the mouth 5 of the inner bag 4 can be suppressed.

[0031] In this embodiment, the recess 4h is provided at the corner 4b3 between the lower wall 4b2 and the peripheral wall 4b1. In this case, the recess 4h functions as a reinforcing rib, increasing the rigidity of the second cylinder 4b, making it easier to rotate the inner bag 4 relative to the outer shell 3 when pulling out the inner bag 4. Furthermore, the corner 4b3 is located inside the outer shell 3. In this case, a gap is less likely to form between the inner bag 4 and the outer shell 3, highlighting the significant technical importance of providing the recess 4h to facilitate the introduction of air into the intermediate space SP1 between the inner bag 4 and the outer shell 3.

[0032] <Details of the opening 5 of the outer shell 3> As shown in Figure 4, the opening end 3a of the outer shell 3 is provided with a base surface 3a1, an annular projection 3a2, and an inner bag facing surface 3a3. The base surface 3a1 is preferably annular. The annular projection 3a2 is positioned outside the base surface 3a1 and protrudes axially from the base surface 3a1. As shown in Figure 4, the base surface 3a1 faces the opening end 41a5 of the outer cylinder 41a of the opening mounting member 8, and the annular projection 3a2 protrudes outward toward the valve body 41e (described later) of the opening mounting member 8. With this configuration, the entry of foreign matter between the inner bag 4 and the outer shell 3 is suppressed by the annular projection 3a2 and the valve body 41e. Furthermore, it is preferable that the apex 3a4 of the annular projection 3a2 is higher than the opening end 41a5. In this case, the entry of foreign matter is further suppressed.

[0033] As shown in Figure 8, the angle β of the inner bag facing surface 3a3 with respect to a reference plane P perpendicular to the central axis C of the opening 5 is, for example, 5 to 45 degrees (15 degrees in this embodiment), and preferably 10 to 30 degrees. Specifically, the angle β may be, for example, 5, 10, 15, 20, 25, 30, 35, 40, or 45 degrees, and may be in the range between any two of the values ​​exemplified here.

[0034] As shown in Figure 7, the outer circumferential surface of the outer shell 3 is provided with a projection 3o and a flange portion 5d, in order from the open end 3a side of the outer shell 3. The projection 3o constitutes the open end 3a. Preferably, a recess 3g is provided on the inner circumferential surface of the projection 3o. The lower surface of the recess 3g becomes the inner bag opposing surface 3a3.

[0035] <Details of the tapered section> In this embodiment, the double-walled container 1 is designed to allow the inner bag 4 to be pulled out from the container body 2. If the force required for this pulling is excessive, it will be difficult to pull the inner bag 4 out of the container body 2. Therefore, it is desirable to reduce the force required to pull out the inner bag 4 (or the force required to twist the inner bag 4 if it is pulled out while twisting it). In an investigation to reduce this force, it was found that during biaxial stretch blow molding, the wall thickness at the lower opening 5b of the outer shell 3 decreases towards the base 5b1, which may result in the formation of an undercut section 4u when the inner bag 4 is pulled out of the container body 2. The undercut section 4u is the part of the outer shell 3 that is closer to the vertical line v shown in Figures 6A to 6B. The greater the wall thickness of the inner bag 4 at the height position H which is the starting point of the undercut section 4u, the greater the force required to pull out the inner bag 4.

[0036] As shown in Figure 6B, in the reference example where the inner tapered portion 3p is not provided, the height position H which is the starting point of the undercut portion 4u is located close to the lower surface 5d1 of the flange portion 5d. At this height position H, the wall thickness of the inner bag 4 is relatively large, so the force required to pull out the inner bag 4 becomes relatively large. On the other hand, in the present embodiment shown in Figure 6A, an inner tapered portion 3p is provided on the outer shell 3 in at least a part of the lower opening portion 5b, configured such that the inner diameter of the outer shell 3 decreases toward the base 5b1 of the lower opening portion 5b. As a result, the height position H which is the starting point of the undercut portion 4u moves toward the base 5b1. Since the wall thickness of the inner bag 4 decreases toward the base 5b1, the force required to pull out the inner bag 4 is reduced by providing the inner tapered portion 3p.

[0037] Preferably, the outer shell 3 has an outer tapered portion 3q configured such that the outer diameter of the outer shell 3 decreases toward the base 5b1 in at least a part of the lower opening portion 5b. In this case, the inner tapered portion 3p is more easily formed.

[0038] If the lengths of the lower opening 5b, inner tapered portion 3p, and outer tapered portion 3q in the axial direction of the mouth 5 of the container body 2 are L, Li, and Lo, then Li / L and Lo / L are preferably 0.50 to 1.00 (in this embodiment, both are 1.00). In this case, the torque required to pull out the inner bag 4 is more effectively reduced. Li / L and Lo / L are preferably 0.75 to 1.00, specifically, for example, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, and 1.00, and may be in the range between any two of the values ​​exemplified here.

[0039] The inner tapered portion 3p has an angle η1 at the point where the angle with respect to the central axis C is maximum, for example, 1 to 20 degrees (4 degrees in this embodiment), and preferably 1 to 10 degrees. Specifically, this angle η1 is, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 degrees, and may be in the range between any two of the values ​​exemplified here. The outer tapered portion 3q has an angle η2 at the point where the angle with respect to the central axis C is maximum, for example, 2 to 25 degrees (7 degrees in this embodiment), and preferably 4 to 12 degrees. Specifically, this angle η2 is, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 degrees, and may be within the range of any two of the values ​​exemplified here. It is preferable that angle η2 is greater than angle η1, and the value of (angle η2 - angle η1) is, for example, 1 to 10 degrees, specifically, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 degrees, and may be within the range of any two of the values ​​exemplified here.

[0040] Furthermore, as shown in Figure 3, if La is the length of the mouth 5 of the container body 2 in the axial direction, then L / La is preferably 0.25 or more (0.36 in this embodiment). The larger the proportion of the mouth 5 occupied by the lower mouth 5b, the more likely it is that the pulling force of the inner bag 4 will increase. Therefore, the larger L / La is, the more significant the technical value of applying the invention of this aspect is. L / La is, for example, 0.25 to 0.60, specifically, for example, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, and may also be in the range between any two of the values ​​exemplified here. L is, for example, 5 to 20 mm (9.7 mm in this embodiment), preferably 8 to 15 mm, specifically, for example 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 mm, and may be in the range between any two of the values ​​exemplified here. La is, for example, 15 to 50 mm (26.8 mm in this embodiment), preferably 20 to 40 mm, specifically, for example 15, 20, 25, 30, 35, 40, 45, 50 mm, and may be in the range between any two of the values ​​exemplified here.

[0041] <Details of the cam mechanism 31> As shown in Figures 10 to 12, the outer circumferential surface 4j of the inner bag 4 (more specifically, the inner bag body 4d) is provided with a protrusion 4g that projects radially outward. As shown in Figure 12A, the lower surface of the protrusion 4g is inclined so that it approaches the open end 5c as it moves in a counterclockwise direction.

[0042] As shown in Figure 10, the outer circumferential surface 4j of the inner bag 4 is provided with a plurality of protrusions 4g, which are offset from each other in the circumferential direction. In this embodiment, two protrusions 4g are offset by 180 degrees in the circumferential direction. Furthermore, the angle at which each protrusion 4g extends is preferably 180 degrees or less, and more preferably 90 degrees or less. This angle is, for example, 15 to 180 degrees, and preferably 30 to 90 degrees (about 45 degrees in this embodiment). These angles are specifically, for example, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, and 180 degrees, and may also be within a range of any two of the values ​​exemplified here.

[0043] The protrusion 4g is positioned below the recess 4h, adjacent to the recess 4h (i.e., below the recess 4h). As shown in Figures 3 and 5, the protrusion 4g is positioned at the opening 5 (preferably the upper opening 5a). As will be described later, the inner bag 4 is formed by biaxially stretched blow molding the inner preform 14. In biaxially stretched blow molding, the portion above the lower surface 5d1 of the flange portion 5d hardly deforms, so as shown in Figure 16, the inner preform 14 is provided with a recess 14h and a protrusion 14g corresponding to the recess 4h and the protrusion 4g. In mass production, the internal preform 14 is transported in an aligned state by supporting and transporting the portion 14b2 corresponding to the lower wall 4b2 with each of the pair of rails 45 of the parts feeder. However, the portion of the portion 14b2 whose circumferential position coincides with the recess 14h or the protrusion 14g is difficult to support with the rail 45. Therefore, if the circumferential positions of the recess 14h and the protrusion 14g are misaligned, the portion of the portion 14b2 that can be easily supported by the rail 45 becomes narrower, making it difficult to stably transport the internal preform 14 with the parts feeder. On the other hand, in this embodiment, the protrusion 4g is positioned adjacent to the recess 4h, so the circumferential positions of the recess 14h and the protrusion 14g coincide, making it easy to stably transport the internal preform 14 with the parts feeder.

[0044] As shown in FIG. 11, a concave groove 3m engageable with the convex strip 4g is provided on the inner peripheral surface of the outer shell 3. The concave groove 3m is preferably provided at the end of the cam rail 3l. The upper surface of the cam rail 3l is inclined so as to approach the open end 3a as it advances in the counterclockwise direction. The convex strip 4g and the concave groove 3m are configured to be engageable by the relative rotation of the inner bag 4 and the outer shell 3 in one direction, and to be disengaged by the relative rotation of the inner bag 4 and the outer shell 3 in the other direction.

[0045] A plurality of cam rails 3l are provided on the inner peripheral surface of the outer shell 3, and the plurality of cam rails 3l are offset from each other in the circumferential direction. In the present embodiment, two cam rails 3l are arranged with a 180-degree offset in the circumferential direction. Further, the angle at which each cam rail 3l extends is preferably 360 degrees or less, and more preferably 270 degrees or less. This angle is, for example, 90 to 360 degrees, and preferably 120 to 240 degrees (180 degrees in the present embodiment). Specifically, this angle is, for example, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360 degrees, and may be within the range between any two of the values exemplified here.

[0046] The concave groove 3m is preferably provided on each cam rail 3l. The explanation of the angle at which the concave groove 3m extends is the same as the explanation of the angle for the above convex strip 4g.

[0047] Before the inner bag 4 is pulled out of the container body 2, the lower surface of the convex strip 4g abuts against the upper surface of the cam rail 3l within the concave groove 3m. The cam mechanism 31 is constituted by the convex strip 4g and the cam rail 3l. When the inner bag 4 is rotated counterclockwise with respect to the outer shell 3, the inner bag 4 is displaced in a direction to come out of the container body 2 by the action of the cam mechanism 31. At this time, the inner bag 4 is twisted and its diameter is reduced. The cam mechanism 31 has an inclined structure in the same direction as a right-handed screw.

[0048] <Details of the rotation restricting structure> It is preferable that the container body 2 is provided with a rotation restricting structure for restricting the relative rotation of the inner bag 4 and the outer shell 3. Examples of this rotation restricting structure include a structure for increasing the frictional force between the inner bag 4 and the outer shell 3, and a structure for engaging the inner bag 4 and the outer shell 3 in a concavo-convex manner in the circumferential direction. In the present embodiment, as shown in FIGS. 10 to 11, the outer shell 3 has an engagement convex portion 3j protruding radially inward on the inner circumferential surface 3n. The engagement convex portion 3j is preferably arranged along the cam rail 3l, and more preferably arranged in the concave groove 3m or at a position adjacent to the concave groove 3m.

[0049] As shown in FIG. 10, the convex strip 4g includes a one-side contact surface 4g1 that contacts the engagement convex portion 3j when relatively rotating in one direction (that is, the engaging direction), and a other-side contact surface 4g2 that contacts the engagement convex portion 3j when relatively rotating in the other direction (that is, the disengaging direction), and a central surface 4g3 between the one-side contact surface 4g1 and the other-side contact surface 4g2. The one-side contact surface 4g1 and the other-side contact surface 4g2 are end surfaces located at the longitudinal ends of the convex strip 4g, respectively. The central surface 4g3 has a similar shape to the portion 3r of the outer shell 3 that faces the central surface 4g3. No protrusion protruding from the central surface 4g3 is provided on the central surface 4g3. At the central surface 4g3, the convex strip 4g has a constant protrusion height from the outer circumferential surface 4j. From the center in the longitudinal direction of the convex strip 4g toward the bases 4g4, 4g5 at both longitudinal ends of the convex strip 4g, the height of the convex strip 4g monotonically decreases.

[0050] In a configuration where another projection is provided on the central surface 4g3 of the protruding rib 4g and this projection abuts against the engaging projection 3j, the projection is prone to becoming thin during molding, which can easily lead to the projection breaking and causing leakage of the contents. On the other hand, in this embodiment, instead of providing another projection on the central surface 4g3, the end face at the longitudinal end of the protruding rib 4g abuts against the engaging projection 3j of the outer shell 3, thereby suppressing the inner bag 4 from rotating unexpectedly relative to the outer shell 3. The end face of the protruding rib 4g is less likely to become thin compared to the case where another projection is provided on the central surface 4g3, so according to this embodiment, the occurrence of damage to the inner bag 4 is suppressed. The protruding rib 4g may be hollow or solid, but when the protruding rib 4g is hollow, the technical significance of abutting the end face at the longitudinal end of the protruding rib 4g against the engaging projection 3j of the outer shell 3 is particularly pronounced. When the inner bag 4 is formed using an inner preform 14 formed by direct blow molding, the protrusions 4g are usually hollow.

[0051] The other-side contact surface 4g2 has a other-side inclination angle θ2, which is the angle of inclination of the other-side contact surface 4g2 with respect to the tangent 4j2 of the outer peripheral surface 4j at the base 4g4 of the other-side contact surface 4g2, which is 5 to 45 degrees (19 degrees in this embodiment), and preferably 10 to 40 degrees. The outer peripheral surface 4j is preferably circular in the above cross-section, and the portion that protrudes from the circular outer peripheral surface 4j is preferably a convex ridge 4g. The other-side inclination angle θ2 is preferably 10 to 30 degrees, specifically, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45 degrees, and may be in the range between any two of the values ​​exemplified here. The smaller the other-side inclination angle θ2, the less likely the convex ridge 4g is to be thinned. Also, if the other-side inclination angle θ2 is greater than 45 degrees, the convex ridge 4g may be thinned too much, and when the other-side contact surface 4g2 is pressed against the engaging protrusion 3j, it may easily deform, resulting in insufficient restriction of relative rotation.

[0052] The inclination angle θ1 on one side, which is the angle of inclination of the outer peripheral surface 4j at the base 4g5 of the contact surface 4g1 with respect to the tangent 4j1, is greater than the inclination angle θ2 on the other side. In this case, the thickness of the contact surface 4g1 on one side tends to be relatively thin, and the torque required for engagement between the convex ridge 4g and the concave ridge 3m can be reduced. The inclination angle θ1 on one side is, for example, 50 to 80 degrees (64 degrees in this embodiment), and is preferably 55 to 75 degrees. Specifically, the inclination angle θ1 on one side is, for example, 50, 55, 60, 65, 70, 75, or 80 degrees, and may be in the range between any two of the values ​​exemplified here. The difference between the inclination angle θ1 on one side and the inclination angle θ2 on the other side is, for example, 30 to 60 degrees (45 degrees in this embodiment), and is preferably 35 to 55 degrees. This difference could be, for example, 30, 35, 40, 45, 50, 55, or 60 degrees, or it could be any range between any two of the values ​​exemplified here.

[0053] The engaging projection 3j has a one-sided contact surface 3j1 that contacts the projection 4g when rotated relative to it in one direction (i.e., the direction of engagement), and a other-sided contact surface 3j2 that contacts the projection 4g when rotated relative to it in the other direction (i.e., the direction of disengagement). The one-sided contact surface 3j1 contacts the one-sided contact surface 4g1, and the other-sided contact surface 3j2 contacts the other-sided contact surface 4g2.

[0054] The inclination angle δ1 of one side contact surface 3j1 with respect to the connecting line 3j6 that connects the base 3j5 of one side contact surface 3j1 and the base 3j4 of the other side contact surface 3j2 is, for example, 20 to 50 degrees (31 degrees in this embodiment), and preferably 25 to 45 degrees. Specifically, the inclination angle δ1 may be, for example, 20, 25, 30, 35, 40, 45, or 50 degrees, and may be in the range between any two of the values ​​exemplified here. The inclination angle δ2 of the other side contact surface 3j2 with respect to the connecting line 3j6 is, for example, 50 to 80 degrees (60 degrees in this embodiment), and preferably 55 to 75 degrees. Specifically, the inclination angle δ2 may be, for example, 50, 55, 60, 65, 70, 75, or 80 degrees, and may be in the range between any two of the values ​​exemplified here. The engaging projection 3j is preferably a solid body, in which case the larger the inclination angle, the greater the torque required for engagement or disengagement. In this embodiment, since the inclination angle δ1 on one side is smaller than the inclination angle δ2 on the other side, a configuration is achieved in which the torque required for engagement between the projection 4g and the recess 3m is relatively low, and the torque required for disengagement between the projection 4g and the recess 3m is relatively high. The difference between the inclination angle δ1 on one side and the inclination angle δ2 on the other side is, for example, 15 to 50 degrees (29 degrees in this embodiment), and preferably 20 to 40 degrees. Specifically, this difference may be, for example, 20, 25, 30, 35, 40, 45, or 50 degrees, and may be in the range between any two of the values ​​exemplified here.

[0055] As shown in Figure 11, the inner bag 4 is provided with a projection 4k on its outer surface 4j that protrudes radially outward. As shown in Figures 10B and 11, the projection 4k is positioned further away from the protruding ridge 4g than the engaging projection 3j, with the protruding ridge 4g engaged with the recessed ridge 3m. The projection 4k is provided so as to overlap the cam rail 3l in the axial direction, which is the direction in which the central axis C (see Figure 2) of the mouth 5 of the container body 2 extends.

[0056] In this embodiment, the inner bag 4 is provided with a projection 4k. Since the projection 4k is provided downstream of the engaging projection 3j in the direction of rotation, the projection 4k does not need to overcome the engaging projection 3j when disengaging the projection 4g from the recessed projection 3m. Therefore, even if the projection 4g is displaced radially inward, the projection 4k is hardly or not displaced radially at all. Furthermore, since the projection 4k is provided so as to overlap the cam rail 3l in the axial direction, even if the entire projection 4g is displaced inward beyond the inner edge of the cam rail 3l, the projection 4k is supported by the cam rail 3l, preventing the projection 4g from falling off the cam rail 3l.

[0057] It is even more preferable that the lower surface of the projection 4k is inclined in the same way as the convex ridge 4g. In this case, when the inner bag 4 and the outer shell 3 are rotated relative to each other in opposite directions, both the convex ridge 4g and the projection 4k move along the cam rail 3l, so that the inner bag 4 can be rotated more stably relative to the outer shell 3.

[0058] The convex ridge 4g and the projection 4k may be composed of separate convex portions that are separated from each other, or they may be separate parts of a single convex portion. Alternatively, the entire structure including the convex ridge 4g and the projection 4k may be interpreted as the convex ridge 4o. In this case, a recess 4g6 is provided in the convex ridge 4o, and the engaging projection 3j engages with the recess 4g6. In this case, the other contact surface 4g2 becomes the side surface of the recess 4g6. The convex ridge 4g is the upstream portion of the convex ridge 4o in the direction of rotation in the other direction, and the projection 4k is the downstream portion of the convex ridge 4o in the direction of rotation in the other direction.

[0059] In this embodiment, as shown in Figure 11, the inner bag 4 is provided with an axial engagement portion 4ma composed of an annular protrusion 4n, and a circumferential engagement portion 4mb composed of a plurality of protrusions 4mb1 arranged circumferentially at a position further from the opening end 5c than the axial engagement portion 4ma. Furthermore, the annular protrusion 4n is also provided with a plurality of protrusions 4mb2 arranged circumferentially, and the protrusions 4mb2 are configured to engage with the mouth attachment member 8 in the circumferential direction. In other words, the circumferential engagement portion 4mb is composed of protrusions 4mb1 and 4mb2. This further suppresses the mouth attachment member 8 from rotating freely relative to the inner bag 4.

[0060] In this embodiment, the inner bag 4 is provided with a movement-restricting portion 4p on its outer circumferential surface 4j that protrudes radially outward. The movement-restricting portion 4p prevents the inner bag 4 from rotating relative to the inner bag 4 in the opposite direction to the direction of relative rotation when the inner bag 4 is pulled out. This prevents the inner bag 4 from being accidentally rotated in the wrong direction.

[0061] As shown in Figure 12A, the movement-restricting portion 4p is provided at a position adjacent to the opening end 5c of the inner bag 4 than the projection 4k. The movement-restricting portion 4p is provided at a position adjacent to the bottom of the inner bag 4 than the recess 4h. The movement-restricting portion 4p is adjacent to the projection 4k in the height direction of the inner bag 4. The movement-restricting portion 4p extends in the circumferential direction of the inner bag 4. The longitudinal length of the movement-restricting portion 4p is preferably shorter than the longitudinal length of the projection 4k. The movement-restricting portion 4p includes a contact surface 4p1, a rear end surface 4p2, and a central surface 4p3.

[0062] The contact surface 4p1 can contact the contact surface 3s, which will be described later. The contact surface 4p1 is formed at the longitudinal end of the movement-restricting portion 4p. The rear end surface 4p2 is formed on the opposite side of the contact surface 4p1. The rear end surface 4p2 is flush with the rear end surface of the projection 4k. The rear end surface of the projection 4k is the end surface of the projection 4k that is opposite to the other side contact surface 4g2. The central surface 4p3 is the surface that connects the contact surface 4p1 and the rear end surface 4p2. The central surface 4p3 extends in the longitudinal direction of the movement-restricting portion 4p. The central surface 4p3 is flush with the outer surface of the projection 4k. The outer surface of the projection 4k is the surface of the projection 4k that is located radially outward of the inner bag 4.

[0063] As shown in Figure 11, the outer shell 3 includes a contact surface 3s that can contact the movement-restricting portion 4p when it is rotated relative to the outer shell 3 in one direction. The contact surface 3s is located on the open end 3a side of the outer shell 3, further than the engaging projection 3j. The contact surface 3s is located further from the groove 3m than the engaging projection 3j.

[0064] In the state shown in Figure 12B, for example, one side contact surface 4g1 is in contact with the end portion 3m1. The end portion 3m1 is the end opposite to the engaging projection 3j of the groove 3m. In this state, the contact surface 4p1 is in contact with the contact surface 3s, for example. Therefore, even if one tries to rotate the inner bag 4 further in one direction while the inner bag 4 is engaged with the outer shell 3, the movement-restricting portion 4p interferes with the contact surface 3s, preventing the inner bag 4 and the outer shell 3 from rotating in one direction. For example, even if the inner bag 4 is accidentally rotated in one direction when removing it from the container body 2, the possibility of the one side contact surface 4g1 moving further in one direction than the end portion 3m1 can be reduced (see Figure 11).

[0065] The configuration of the movement-restricting portion 4p is not limited to the configuration described above. The movement-restricting portion 4p only needs to be able to prevent the one-sided contact surface 4g1 from moving further in one direction than the end portion 3m1. For example, the movement-restricting portion 4p may be provided at a position adjacent to the bottom side of the inner bag 4 than the projection 4k. In this case, the contact surface 3s may be provided at a position adjacent to the bottom side of the outer shell 3 than the engaging projection 3j. Similarly, in the inner preform 14, the movement-restricting portion 14p may be provided at a position adjacent to the bottom 14c side of the inner preform 14 than the projection 14k.

[0066] <Detailed configuration of the mouth attachment member 8> As shown in Figures 4 and 5, the mouth attachment member 8 preferably has a discharge port 8d for discharging the contents of the inner bag 4. Furthermore, the mouth attachment member 8 preferably includes a nozzle 8c.

[0067] The cap 8a preferably comprises a cap body 41 and an overcap 42. The cap body 41 is configured to engage with a protruding portion 4c and has a discharge port 8d. The overcap 42 is configured to open and close the discharge port 8d. Figure 4 shows the closed state with the discharge port 8d closed, and Figure 5 shows the open state with the discharge port 8d open. In this embodiment, the cap body 41 and the overcap 42 are connected by a hinge 43, but they do not have to be connected. The overcap 42 is preferably able to engage with the cap body 41 by a screw or snap fit.

[0068] The cap body 41 comprises an outer cylinder 41a, an inner cylinder 41b, a nozzle 8c, and an upper wall 41d. The inner cylinder 41b is positioned inside the outer cylinder 41a. The outer cylinder 41a and the inner cylinder 41b are connected via the upper wall 41d. The nozzle 8c is positioned above the upper wall 41d. The upper wall 41d is provided with a flow hole 41i, through which the flow passage between the inner cylinder 41b and the nozzle 8c is connected. The tip of the nozzle 8c becomes the discharge port 8d. The inner cylinder 41b is inserted into the protruding portion 4c and is in close contact with the inner surface 4f1 of the sealing cylinder portion 4f. As a result, the inner cylinder 41b and the sealing cylinder portion 4f are frictionally engaged in the circumferential direction. An engagement portion 8b is provided on the inner circumferential surface of the outer cylinder 41a.

[0069] The overcap 42 comprises an outer cylinder 42a, an inner cylinder 42b, and an upper wall 42d. The inner cylinder 42b is positioned inside the outer cylinder 42a. The outer cylinder 42a and the inner cylinder 42b are connected via the upper wall 42d. The upper wall 42d does not have an outlet for discharging the contents of the inner bag 4.

[0070] When the discharge port 8d is closed with the overcap 42, the inner cylinder 42b is inserted into the nozzle 8c of the cap body 41 and is in close contact with the inner surface of the nozzle 8c. Also, the bottom surface of the outer cylinder 42a is in contact with the upper wall 41d of the cap body 41. From this state, by gripping the outer cylinder 42a and applying an upward force to the overcap 42, the overcap 42 can be separated from the cap body 41 and the discharge port 8d can be opened.

[0071] The nozzle 8c is provided with a discharge valve 44. The discharge valve 44 is configured to allow the discharge of the contents while preventing outside air from entering the inner bag 4. The discharge valve 44 is located below the lower end of the inner cylinder 42b when the overcap 42 is closed.

[0072] The mouth mounting member 8 is provided with a valve body 41e. The valve body 41e is a highly flexible part, and the displacement of the valve body 41e enables the function of the airflow regulating section 9 to be realized. Details of the valve body 41e will be explained when describing the airflow regulating section 9.

[0073] <Details of the airflow restricting section 9> As shown in Figure 4, the double-walled container 1 is provided with an airflow restricting section 9. The airflow restricting section 9 restricts the airflow between the external space SP2 of the container body 2 and the intermediate space SP1. The airflow restricting section 9 is configured to restrict the airflow through the gap G (shown in Figure 13B) between the outer shell 3 and the mouth attachment member 8.

[0074] When the user presses the body 6 of the container body 2 to dispense the contents from the double container 1, the outer shell 3 is compressed. The air flow restrictor 9 prevents air from leaking out of the intermediate space SP1 when the outer shell 3 is compressed, so the pressure in the intermediate space SP1 increases with the compression of the outer shell 3, making it easier for the compressive force applied to the outer shell 3 to be transmitted to the inner bag 4. As a result, the inner bag 4 is compressed along with the compression of the outer shell 3, and the contents inside the inner bag 4 are dispensed through the discharge valve 44. The inner bag 4 is contracted by the discharge of the contents. The discharge valve 44 is configured to prevent outside air from entering the inner bag 4, so outside air does not enter the inner bag 4, and the inner bag 4 remains contracted.

[0075] When the compression of the outer shell 3 is released, the outer shell 3 attempts to return to its original shape due to its own restoring force. At this time, the pressure in the intermediate space SP1 decreases. The airflow restricting section 9 is configured to allow air to flow from the external space SP2 to the intermediate space SP1 when the compression of the outer shell 3 is released. As a result of the decrease in pressure in the intermediate space SP1, outside air is quickly introduced into the intermediate space SP1 through the airflow restricting section 9, and the outer shell 3 is quickly restored to its original shape.

[0076] Furthermore, as shown in Figure 13, in this embodiment, the intermediate space SP1 and the external space SP2 are connected via the air flow restricting section 9 through the gap G1 between the open end 3a of the outer shell 3 and the inner bag 4. This makes it possible to introduce air into the intermediate space SP1 without forming an outside air inlet hole in the outer shell 3, thus eliminating the need for the process of forming an outside air inlet hole and reducing the effort required to manufacture the double-walled container 1.

[0077] In this embodiment, the airflow restricting section 9 comprises a valve body 41e and a contact portion 3i. The valve body 41e is provided on the mouth mounting member 8, and the contact portion 3i is provided on the outer shell 3. The airflow through the airflow restricting section 9 is suppressed by the contact between the valve body 41e and the contact portion 3i. Furthermore, the airflow through the airflow restricting section 9 is permitted by providing a gap G between the valve body 41e and the contact portion 3i. With this configuration, it is possible to construct the airflow restricting section 9 without providing additional members such as a check valve.

[0078] In this embodiment, the valve body 41e is provided so as to protrude from the cap body 41 toward the outer shell 3. The valve body 41e is provided around the entire circumference of the cap body 41. The outer shell 3 has an annular projection 3a2 at its open end 3a. The valve body 41e is positioned radially inward of the annular projection 3a2. The contact portion 3i is provided on the inner circumferential surface 3a21 of the annular projection 3a2. With this configuration, as the outer shell 3 is compressed, a force is applied to the valve body 41e in a radially outward direction, causing the valve body 41e to be pressed against the contact portion 3i, as shown in Figure 4B, thereby suppressing air leakage from the intermediate space SP1. On the other hand, when the compression of the outer shell 3 is released, the pressure in the intermediate space SP1 decreases, causing the valve body 41e to displace toward the inside of the container body 2, as shown in Figure 13B. As a result, a gap G is formed between the valve body 41e and the inner circumferential surface 3a21, allowing air to flow into the intermediate space SP1. With this configuration, the valve body 41e moves easily in response to pressure changes in the intermediate space SP1, so the switching between suppressing and allowing airflow through the airflow regulating section 9 is smooth. In addition, since the annular projection 3a2 is positioned on the radially outer side of the valve body 41e, the possibility of malfunctions such as damage to the valve body 41e can be reduced.

[0079] The thickness of the valve body 41e (length in the direction perpendicular to the axial direction) is smaller than the thickness of the cap body 41. Preferably, the thickness of the valve body 41e is such that it can be deformed by the negative pressure generated in the intermediate space SP1.

[0080] The thickness of the valve body 41e is, for example, 0.1 mm to 1.0 mm (0.4 mm in this embodiment), preferably 0.2 mm to 0.6 mm. Specifically, the thickness of the valve body 41e is, for example, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00 mm, and may be in the range between any two of the values ​​exemplified here.

[0081] The length of the valve body 41e (length along the axial direction) is longer than the protruding height of the annular projection 3a2. The length of the valve body 41e is, for example, 0.5 mm to 5.0 mm (2.0 mm in this embodiment), and preferably 1.0 mm to 3.0 mm. Specifically, the length of the valve body 41e is, for example, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0 mm, and may be in the range between any two of the values ​​exemplified here.

[0082] The tip portion 41e1 of the valve body 41e is spaced apart from the outer shell 3. Specifically, the tip portion 41e1 is spaced apart from the base surface 3a1. Therefore, when the pressure in the intermediate space SP1 decreases, the valve body 41e displaces smoothly. Consequently, air can flow smoothly into the intermediate space SP1. The tip portion 41e1 constitutes the open end 41a5 of the cap body 41.

[0083] In this embodiment, when no negative pressure is generated in the intermediate space SP1, the valve body 41e is in contact with the inner circumferential surface 3a21 of the annular projection 3a2, but it is not required that it be in contact. Even in the latter case, as the internal pressure of the intermediate space SP1 increases, the valve body 41e is displaced toward the inner circumferential surface 3a21 and the valve body 41e comes into contact with the inner circumferential surface 3a21, thereby making the intermediate space SP1 a sealed space.

[0084] The valve body 41e is made of, for example, an elastomer. In this case, the valve body 41e is particularly susceptible to displacement due to changes in the internal pressure of the intermediate space SP1. The portion of the mouth mounting member 8 excluding the valve body 41e may be made of, for example, polyolefin. It is preferable that the valve body 41e and the portion of the mouth mounting member 8 other than the valve body 41e are formed integrally. One method for integrally forming the valve body 41e and the portion is two-color molding. In two-color molding, for example, the portion may be formed of a resin such as polyolefin, and the valve body 41e may be formed by two-color molding of the formed portion with an elastomer. However, the method for forming the valve body 41e is not particularly limited.

[0085] <Attachment of the mouth attachment member 8> As shown in Figure 5, the mouth attachment member 8 can be attached to the mouth 5 while supporting the projection 3o or flange 5d. The mouth attachment member 8 is preferably of the snap-fit ​​type (i.e., snap-fit ​​type), and while supporting the projection 3o or flange 5d, the mouth attachment member 8 is placed over the projection 4c, and when a downward force is applied to the mouth attachment member 8 in that state, the engaging portion 8b overcomes the axial engaging portion 4ma, and the engaging portion 8b engages with the axial engaging portion 4ma and the circumferential engaging portion 4mb, thereby attaching the mouth attachment member 8 to the mouth 5. The engaging portion 8b engages with the axial engaging portion 4ma in the axial direction and with the circumferential engaging portion 4mb in the circumferential direction. The circumferential engagement between the circumferential engaging portion 4mb and the engaging portion 8b may be a concave-convex engagement or a frictional engagement.

[0086] <Removal of Inner Bag 4> The mouth attachment member 8 is engaged with the protruding portion 4c of the inner bag 4 in the circumferential and axial directions, and is configured to rotate relative to the outer shell 3 so that the inner bag 4 twists as the mouth attachment member 8 rotates. Then, due to the action of the cam mechanism 31 provided between the inner bag 4 and the outer shell 3, the inner bag 4 is configured to move in a direction that allows it to come out of the container body 2 as it rotates.

[0087] With this configuration, by rotating the mouth attachment member 8, the inner bag 4 can be twisted and moved in a direction that allows it to come out of the container body 2. After that, by pulling the mouth attachment member 8, the inner bag 4 can be pulled out of the container body 2.

[0088] 1-2. Manufacturing Method of Double-Walled Container 1 The container body 2 can be manufactured by biaxial stretch blow molding of the preform 15 shown in Figure 15. Alternatively, the double-walled container 1 can be manufactured by attaching the mouth attachment member 8 to the container body 2.

[0089] <Composition of inner preform 14, outer preform 13, and preform 15> The preform 15 comprises an inner preform 14 which becomes the inner bag 4 and an outer preform 13 which becomes the outer shell 3.

[0090] As shown in Figure 14, the inner preform 14 is a bottomed cylindrical shape and comprises a mouth portion 14a, a body portion 14b, and a bottom portion 14c. A projection 14d is provided on the mouth portion 14a. As shown in Figures 14 to 15, the projection 14d is a portion that protrudes from the open end 13f of the outer preform 13 in the preform 15. The projection 14d remains in its original shape without deformation during molding and becomes the projection 4c. The projection 14d is provided with an engaging portion 14m, which becomes the engaging portion 4m. The bottom portion 14c is provided so as to close the lower end of the body portion 14b.

[0091] Furthermore, the inner preform 14 has a recess 14h in the portion facing the outer preform 13. Preferably, the recess 14h is formed so that the inner preform 14 protrudes inward within the recess 14h. The inner preform 14 has a ridge 14g on its outer circumferential surface 14j that protrudes radially outward. The ridge 14g is positioned adjacent to the recess 14h, on the bottom 14c side of the recess 14h. With this configuration, as shown in Figure 16, the inner preform 14 can be supported by a pair of rails 45 of the parts feeder and transported stably.

[0092] As shown in Figure 14, the outer preform 13 is a bottomed cylindrical shape and comprises a mouth portion 13a, a body portion 13b, and a bottom portion 13c. The bottom portion 13c is provided to close the lower end of the body portion 13b.

[0093] As shown in Figure 17, the outer preform 13 includes a flange portion 15e. The outer preform 13 has an inner tapered portion 13p at an adjacent portion 13g adjacent to the lower surface 15e1 of the outer preform 13, on the bottom 13c side of the outer preform 13, where the inner diameter of the outer preform 13 decreases toward the bottom 13c. The outer preform 13 also has an outer tapered portion 13q at the adjacent portion 13g where the outer diameter of the outer preform 13 decreases toward the bottom 13c. In this case, the inner tapered portion 13p is formed on the outer shell 3, making it easier to reduce the force required to pull out the inner bag 4.

[0094] With respect to the direction in which the central axis C1 of the opening 13a of the outer preform 13 extends (hereinafter referred to as the "outer preform axis direction"), if the length of the adjacent portion 13g is pL, it is preferable that pL is the same as the length L of the lower opening 5b. The length of pL in the outer preform axis direction is, for example, 5 to 20 mm (9.7 mm in this embodiment), preferably 8 to 15 mm, and specifically, for example, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 mm, and may also be in the range between any two of the values ​​exemplified here.

[0095] If the lengths of the inner tapered portion 13p and the outer tapered portion 13q in the axial direction of the outer preform are pLi and pLo, respectively, then it is preferable that pLi / pL and pLo / pL are 0.50 to 1.00, respectively. In this case, the torque required to pull out the inner bag 4 is more effectively reduced. It is preferable that pLi / pL and pLo / pL are 0.75 to 1.00, respectively, specifically for example 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, and 1.00, and may be in the range between any two of the values ​​exemplified here.

[0096] The inner tapered portion 13p has an angle ε1 at the point where the angle with respect to the central axis C1 is maximum in the adjacent portion 13g, for example, 2 to 30 degrees (13 degrees in this embodiment), and preferably 5 to 20 degrees. Specifically, this angle ε1 is, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 degrees, and may be in the range between any two of the values ​​exemplified here.

[0097] The outer tapered portion 13q has an angle ε2 at the point where the angle with respect to the central axis C1 is maximum in the adjacent portion 13g, which is, for example, 2 to 25 degrees (7 degrees in this embodiment), and preferably 4 to 12 degrees. Specifically, this angle ε2 is, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 degrees, and may be in the range between any two of the values ​​exemplified here.

[0098] It is preferable that angle ε1 is greater than angle ε2, and the value of (angle ε1 - angle ε2) is, for example, 1 to 25 degrees, specifically, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 degrees, and may also be in the range between any two of the values ​​exemplified here.

[0099] As shown in Figure 15, the preform 15 can be formed by placing the outer preform 13 over the inner preform 14. In the preform 15, the openings 14a and 13a face each other, and the body portions 14b and 13b face each other.

[0100] The mouth portions 13a and 14a become the mouth portion 15a of the preform 15, the body portions 13b and 14b become the body portion 15b of the preform 15, and the bottom portions 13c and 14c become the bottom portion 15c of the preform 15. In this embodiment, the portion of the flange portion 15e on the bottom portion 15c side of the lower surface 15e1 is mainly stretched in biaxial stretch blow molding. The portion of the flange portion 15e on the opening end 15f side of the lower surface 15e1 is hardly deformed during molding, and the outer shape of the adjacent portion 13g is also hardly deformed during biaxial stretch molding. Regarding the portion that is hardly deformed during biaxial stretch molding, the contents described in relation to the container body 2 are also applicable to the preform 15, insofar as they do not contradict the intent of the description.

[0101] <Materials and Manufacturing Methods of Inner Preform 14, Outer Preform 13, and Preform 15> The inner preform 14 and outer preform 13 can be formed from thermoplastic resins such as polyester (e.g., PET) or polyolefin (e.g., polypropylene, polyethylene). The outer preform 13 can be formed by direct blow molding or injection molding. The inner preform 14 is preferably formed by direct blow molding using a molten cylindrical parison. Direct blow molding has the advantage of making it easier to thin the wall and create multiple layers compared to injection molding. A seal portion is formed at the bottom 14c of the inner preform 14 formed by direct blow molding by welding the inner surfaces of the parisons together. This seal portion has relatively low strength and is prone to tearing during biaxial stretch blow molding, so in order to increase the strength of the seal portion, it is preferable that the seal portion is a protruding seal portion 14t that protrudes from the bottom 14c of the inner preform 14.

[0102] <Biaxial Stretch Blow Molding Process> The biaxial stretch blow molding process for the preform 15 includes, in one example, a heating process and a stretching process. Each process is described below.

[0103] <Heating Process> In the heating process, the preform 15 is heated and softened to a softened state. In one example, the preform 15 can be heated by bringing it close to a heater. In one example, the preform 15 can be heated while rotating. In one example, the heater consists of multiple rod-shaped heaters arranged along the side of the preform 15, but other configurations are also possible.

[0104] <Stretching Process> In the stretching process, the softened preform 15 is stretched to form the shape of the container body 2. In one example, the stretching process comprises a first stretching process and a second stretching process.

[0105] <First and Second Stretching Steps> In the first stretching step, the preform 15 is stretched along the first axial direction (i.e., the longitudinal direction). The first axis is, for example, parallel to the central axis C of the mouth portion 5. In the second stretching step, the preform 15 is stretched (i.e., expanded) in the second axial direction (i.e., the transverse direction) by blowing air into the inner preform 14 to shape it to the shape of the cavity surface of the split mold, and the container body 2 shown in Figure 2 is obtained.

[0106] 2. The double-walled container 1 according to the second embodiment will be described using Figure 18 of the second embodiment. The second embodiment is the same as the first embodiment except for the configuration of the air flow restricting section 9, and the contents described in the first embodiment are applicable to this embodiment as long as they do not contradict the spirit of the first embodiment. The differences will be mainly described below, and redundant explanations will be omitted as appropriate.

[0107] As shown in Figure 18, in the second embodiment, the tip of the outer cylinder 41a is located outside the annular projection 3a2. The valve body 41e is provided so as to protrude radially inward from the cap body 41. The valve body 41e protrudes from the inner circumferential surface of the outer cylinder 41a. Preferably, the valve body 41e is annular. The valve body 41e is provided at a position away from the tip of the outer cylinder 41a. In this embodiment, the valve body 41e is in contact with the open end 3a of the outer shell 3. More specifically, the valve body 41e is in contact with the annular projection 3a2 provided on the open end 3a. That is, the contact portion 3i is provided on the annular projection 3a2. In this embodiment, the valve body 41e is inclined so as it moves radially from the outside to the inside. The valve body 41e is in contact with the outer edge of the annular projection 3a2 and spaced apart from the inner edge of the annular projection 3a2. Furthermore, when the outer shell 3 is not compressed, the valve body 41e does not need to be in contact with the contact portion 3i.

[0108] With this configuration, as the outer shell 3 is compressed, a force is applied to the valve body 41e in the direction toward the contact portion 3i (i.e., the open end 3a), causing the valve body 41e to be pressed against the contact portion 3i, as shown in Figure 18, thereby suppressing air leakage from the intermediate space SP1.

[0109] When the compression of the outer shell 3 is released, the pressure in the intermediate space SP1 decreases, and as shown in Figure 19, the valve body 41e is displaced away from the contact portion 3i (i.e., the open end 3a). As a result, a gap G is formed between the valve body 41e and the contact portion 3i, and air flows into the intermediate space SP1. With this configuration, the valve body 41e moves in response to pressure changes in the intermediate space SP1, and it becomes possible to switch between suppressing and allowing airflow through the airflow regulating portion 9.

[0110] In the second embodiment, for example, the structure can be configured to introduce air into the intermediate space SP1 through the gap G without forming an outside air inlet hole in the outer shell 3. This reduces the effort required to manufacture the double-walled container 1. Furthermore, it eliminates the need to provide additional components such as check valves, thus reducing the number of parts required to manufacture the double-walled container 1.

[0111] In this embodiment, the valve body 41e is in contact with the outer edge of the annular projection 3a2 and spaced apart from the inner edge of the annular projection 3a2. As a result, the force required to displace the valve body 41e upwards to the container body 2 is reduced compared to the case where the valve body 41e is in contact with both the outer and inner edges of the annular projection 3a2. Therefore, when the pressure in the intermediate space SP1 decreases, the valve body 41e can be smoothly displaced, and air can flow smoothly into the intermediate space SP1.

[0112] 3. Other Embodiments The direction of relative rotation of each component may be reversed from the above embodiment. That is, in the above embodiment, the inner bag 4 is displaced in a direction that causes it to come out of the container body 2 when rotated in the direction that loosens the right-hand screw, but it may be configured so that the inner bag 4 is displaced in a direction that causes it to come out of the container body 2 when rotated in the direction that loosens the left-hand screw. In this case, the lower surface of the protrusion 4g and the upper surface of the cam rail 3l are inclined so that, when viewed from the open end side of the container body 2, they approach the open end 5c as they proceed clockwise. Furthermore, it is preferable that the protrusion 6d2 be shaped to extend in a clockwise inclination from the boundary 6e toward the base 5b1 of the mouth 5.

[0113] In the first embodiment, an example was described in which the annular projection 3a2 is provided on the open end 3a of the outer shell 3. However, the annular projection 3a2 only needs to be provided on the outer shell 3 and may be provided on a part other than the open end 3a. For example, the annular projection 3a2 may be provided on the flange portion 5d. In this case, the annular projection 3a2 is provided so as to protrude from the upper surface of the flange portion 5d toward the open end 3a. The valve body 41e abuts against the inner circumferential surface of the annular projection 3a2 of the flange portion 5d.

[0114] Similarly in the second embodiment, the annular projection 3a2 may be provided on a part of the outer shell 3 other than the open end 3a. The annular projection 3a2 may be provided on the flange portion 5d, for example. In this case, the valve body 41e abuts against the annular projection 3a2 of the flange portion 5d.

[0115] In the first and second embodiments, examples were described in which the valve body 41e is provided around the entire circumference of the cap body 41. However, the valve body 41e may be provided only around a portion of the cap body 41.

[0116] In some cases, it is desirable to color the container body 2 to improve its aesthetic appearance. However, colored materials have poor recyclability, so from a recyclability standpoint, coloring the container body 2 is undesirable. To solve this problem, only the inner bag 4 of the outer shell 3 can be colored. This is preferable because it improves the aesthetic appearance of the container body 2 without worsening the recyclability of the outer shell 3. In this case, it is preferable that the outer shell 3 has sufficient light transmission to allow the inner bag 4 to be visible, and is preferably transparent.

[0117] (Second Perspective) The second perspective of the present invention will now be explained. Matters described in the first perspective are applicable to this perspective insofar as they do not contradict the spirit of the first perspective, and matters described in this perspective are applicable to the first perspective insofar as they do not contradict the spirit of the first perspective. The following explanation will focus on the differences from the first perspective.

[0118] 1. The double-walled container 1 of the first embodiment according to the second aspect of the present invention will be described with reference to Figures 20 to 28 of the first embodiment.

[0119] 1-1. Configuration of the Double-Walled Container 1 <Basic Configuration> As shown in Figures 20 to 21, the double-walled container 1 of the first embodiment of the second aspect of the present invention comprises a container body 2 and a cap 8a. The double-walled container 1 is a bottle-shaped container capable of holding beverages, seasonings, etc. The double-walled container 1 is, for example, a squeeze-type container configured to allow the contents inside the container body 2 to be discharged by compressing the body portion 6 of the container body 2, or an inclined-discharge type container in which the contents can be discharged by inclining the double-walled container 1 so that the mouth portion 5 of the double-walled container 1 is on the lower side.

[0120] <Outer shell 3 and inner bag 4> As shown in Figures 22 and 24, the protruding portion 4c of the inner bag 4 is provided with an engaging portion 4m to which the cap 8a can be attached. The engaging portion 4m comprises an axial engaging portion 4ma that engages with the cap 8a in the axial direction and a circumferential engaging portion 4mb that engages with the cap 8a in the circumferential direction. The axial engaging portion 4ma is composed of an annular protrusion. The circumferential engaging portion 4mb is composed of a plurality of protrusions that are spaced apart in the circumferential direction. The outer shell 3 is provided with first and second flange portions 3f1 and 3f2 in order from the open end 3a side.

[0121] The inner bag 4 comprises a first cylinder 4a and a second cylinder 4b. As shown in Figure 24, it is preferable that the lower surface 4b4 of the second cylinder 4b is in contact with and supported by the inner bag support surface 3a5. By supporting the lower surface 4b4 with the inner bag support surface 3a5, the inner bag 4 is prevented from falling into the outer shell 3. The inner bag support surface 3a5 may be flush with the opening end 3a, or it may be provided at a lower position than the opening end 3a. In this embodiment, the inner bag support surface 3a5 is provided at a lower position than the opening end 3a. Therefore, a part of the second cylinder 4b is located inside the outer shell 3, and the rest is located outside the outer shell 3.

[0122] <Cap 8a> As shown in Figures 20 to 21, the cap 8a is attached to the mouth 5 of the container body 2, and preferably to the protruding portion 4c of the inner bag 4.

[0123] As shown in Figures 23 to 26, the cap 8a comprises a cap body 41 and an overcap 42. The cap body 41 is attached to the container body 2. The cap body 41 is attached to the inner bag 4 (more specifically, the protruding portion 4c). The cap body 41 has a discharge port 8d for discharging the contents of the inner bag 4. The overcap 42 is attached to the cap body 41. The overcap 42 is configured to open and close the discharge port 8d. Preferably, the overcap 42 is attached to the cap body 41 by screwing it in.

[0124] As shown in Figure 24, the cap body 41 comprises an outer cylinder 41a, an inner cylinder 41b, a nozzle 8c, and an upper wall 41d. The inner cylinder 41b is positioned inside the outer cylinder 41a. The outer cylinder 41a and the inner cylinder 41b are connected via the upper wall 41d. The nozzle 8c is positioned above the upper wall 41d. The upper wall 41d is provided with a flow hole 41i, through which the flow passage between the inner cylinder 41b and the nozzle 8c is connected. The tip of the nozzle 8c becomes the discharge port 8d. The inner cylinder 41b is inserted into the protruding portion 4c and is in close contact with the inner surface 4f1 of the sealing cylinder portion 4f. The cap body 41 (more specifically the nozzle 8c) is provided with a male threaded portion 41k. The male threaded portion 41k is screwed into a female threaded portion 42e provided on the overcap 42.

[0125] An engaging portion 8b is provided on the inner circumferential surface of the outer cylinder 41a. The engaging portion 8b engages axially with the axial engaging portion 4ma and circumferentially with the circumferential engaging portion 4mb. In this way, the cap body 41 engages circumferentially with the inner bag 4. In this embodiment, as shown in Figure 26B, a plurality of engaging protrusions 41p are provided on the inner circumferential surface of the outer cylinder 41a, spaced apart circumferentially at positions further from the lower end 41o than the engaging portion 8b, and the engaging protrusions 41p may be configured to engage circumferentially with the inner bag 4. In this case, the engaging protrusions 41p become the circumferential engaging portion. The engaging protrusions 41p can be omitted if they are not needed.

[0126] The outer cylinder 41a comprises a first cylinder 41a1 and a second cylinder 41a2. The second cylinder 41a2 is positioned below the first cylinder 41a1. The outer diameter of the second cylinder 41a2 is larger than the outer diameter of the first cylinder 41a1. If the outer diameter of the first cylinder 41a1 is D1 and the outer diameter of the second cylinder 41a2 is D2, then the value of (D2-D1) is, for example, 1.0 to 5.0 mm (3.0 mm in this embodiment), and preferably 2.0 to 4.0 mm. Specifically, this value is, for example, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0 mm, and may be in the range between any two of the values ​​exemplified here. A step is provided between the first cylinder 41a1 and the second cylinder 41a2.

[0127] The engaging portion 8b is provided on the second cylinder 41a2. The first cylinder 41a1 and the second cylinder 41a2 are connected via a thin-walled portion 41a3. The second cylinder 41a2 is located on the tip side of the outer cylinder 41a than the first cylinder 41a1. The second cylinder 41a2 may be configured to be separable from the first cylinder 41a1 by tearing the thin-walled portion 41a3. In this case, it becomes easier to remove the cap body 41 from the inner bag 4 after pulling out the inner bag 4.

[0128] The overcap 42 comprises, in order from the outside, an outer cylinder 42a, a support cylinder 42c, a threaded cylinder 42f, and an inner cylinder 42b. These cylinders are connected to each other via an upper wall 42d. The threaded cylinder 42f is provided with a female threaded portion 42e. When the overcap 42 is attached to the cap body 41, the lower end 42h of the outer cylinder 42a is preferably facing and in contact with the upper surface 41a4 of the second cylinder 41a2. The outer diameter of the outer cylinder 42a at the lower end 42h is preferably the same as the outer diameter of the second cylinder 41a2.

[0129] The overcap 42 is attached to the cap body 41 by screwing the female thread portion 42e and the male thread portion 41k together. At this time, the inner cylinder 42b is inserted into the nozzle 8c of the cap body 41 and makes close contact with the inner surface of the nozzle 8c, closing the discharge port 8d. Also, the tip of the support cylinder 42c abuts against the upper wall 41d. From this state, by gripping the outer cylinder 42a and rotating the overcap 42 in the direction of loosening the screw, the overcap 42 can be separated from the cap body 41 and the discharge port 8d can be opened.

[0130] As shown in Figure 25, the outer circumferential surface of the overcap 42 is provided with an anti-slip shape 42g. The outer surface of the cap body 41 is provided with an anti-slip shape 41m. The anti-slip shapes 42g and 41m are shapes that suppress slippage when gripping and attempting to rotate the overcap 42 or the cap body 41, and include a concave and concave shape with convex and concave parts arranged alternately in the circumferential direction (e.g., knurled shape), a shape with a roughened outer circumferential surface, and a polygonal prism shape (e.g., a hexagonal to dodecagonal prism shape). Providing the anti-slip shape 42g makes it easier to remove the overcap 42. Providing the anti-slip shape 41m makes it easier to twist and reduce the diameter of the inner bag 4 by rotating the cap body 41.

[0131] Incidentally, when the double container 1 contains contents, the overcap 42 is rotated to open the discharge port 8d and discharge the contents. On the other hand, after the double container 1 is empty, the cap body 41 is rotated to twist and reduce the diameter of the inner bag 4, making it easier to pull out the inner bag 4. Thus, the overcap 42 and the cap body 41 rotate in different directions. If the cap body 41 is accidentally rotated when the double container 1 contains contents, the inner bag 4 will be reduced in diameter, and the contents may spill out when the overcap 42 is removed. This problem is particularly likely to occur when the direction of rotation of the overcap 42 when removing the overcap 42 and the direction of rotation of the cap body 41 when twisting and reducing the diameter of the inner bag 4 coincide (for example, when both are counterclockwise), and in this case, the significance of applying the present invention is particularly evident. Furthermore, in a cap 8a configured such that a stopper is provided on the cap body 41 before use of the double container 1, preventing the contents from being dispensed, and the cap body 41 is opened as the overcap 42 is rotated to allow the contents to be dispensed, a relatively large force is required to open the overcap 42 when first rotating it, making it easy to accidentally grip the cap body 41 together with the overcap 42. Therefore, the significance of the present invention is particularly evident when the cap 8a has such a configuration.

[0132] To suppress the occurrence of such problems, in this embodiment, at least a portion of the anti-slip shape 41m is a first anti-slip shape 41m1 provided in a first region 41n1 that is covered by the overcap 42 when the overcap 42 is attached. The first region 41n1 is the region where the first anti-slip shape 41m1 is provided. With this configuration, it is difficult to rotate the cap body 41 when the overcap 42 is attached, so that the cap body 41 is not unintentionally rotated when trying to remove the overcap 42 is suppressed. The first region 41n1 is preferably provided in the first cylinder 41a1. The first region 41n1 may be provided over the entire first cylinder 41a1, or it may be provided only in a part of the first cylinder 41a1.

[0133] The region where the first anti-slip shape 41m1 is provided (i.e., the first region 41n1) has an axial length of, for example, 1.0 to 8.0 mm (3.3 mm in this embodiment), preferably 2.0 to 6.0 mm, and more preferably 2.5 to 5.0 mm. Specifically, this length is, for example, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0 mm, and may be in the range between any two of the values ​​exemplified here. If this length is too short, the effect of providing the first anti-slip shape 41m1 tends to be insufficient, and if this length is too long, the cap 8a may become too large. It is preferable that the first anti-slip shape 41m1 does not engage with the overcap 42 in the circumferential direction, and it is even more preferable that the first anti-slip shape 41m1 does not abut the overcap 42.

[0134] The entire anti-slip shape 41m may be the first anti-slip shape 41m1, or only a part of the anti-slip shape 41m may be the first anti-slip shape 41m1. In order to cover the first region 41n1 on which the first anti-slip shape 41m1 is provided with the overcap 42, the outer diameter of the part on which the first region 41n1 is provided must be smaller than that of the overcap 42. However, when the outer diameter is small, there is a problem that the force required to generate the torque necessary to twist the inner bag 4 becomes larger. This problem is particularly noticeable when the entire anti-slip shape 41m is the first anti-slip shape 41m1.

[0135] Therefore, it is preferable that the anti-slip shape 41m includes a second anti-slip shape 41m2 provided in a second region 41n2 that is not covered by the overcap 42 when the overcap 42 is attached. The second region 41n2 is the region where the second anti-slip shape 41m2 is provided. Since the second region 41n2 is not covered by the overcap 42, the outer diameter of the part where the second region 41n2 is provided is more easily made larger than the outer diameter of the part where the first region 41n1 is provided. For this reason, when the cap body 41 is gripped in the second region 41n2 (specifically, by pressing a gripping part such as a finger against the second region 41n2) and the cap body 41 is rotated, the force required to generate the torque necessary to twist the inner bag 4 is reduced. It is preferable that the second region 41n2 is provided in the second cylinder 41a2. The second region 41n2 may be provided over the entire second cylinder 41a2, or it may be provided only in a part of the second cylinder 41a2.

[0136] The region where the second anti-slip shape 41m2 is provided (i.e., the second region 41n2) has an axial length of, for example, 1.0 to 6.0 mm (3.8 mm in this embodiment), preferably 2.0 to 5.0 mm, and more preferably 3.0 to 4.5 mm. Specifically, this length may be, for example, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, or 6.0 mm, and may be in the range between any two of the values ​​exemplified here. If this length is too short, the effect of providing the second anti-slip shape 41m2 is likely to be insufficient, and if this length is too long, it may become easier to rotate the cap body 41 with the overcap 42 attached, and there is a risk that the cap body 41 may be rotated unintentionally.

[0137] If the length of the first region 41n1 is L1 and the length of the second region 41n2 is L2, then L2 / L1 is, for example, 0.3 to 3.0, and preferably 0.5 to 2.0. If this value is too small, the effect of providing the second anti-slip shape 41m2 tends to be insufficient, and if this value is too large, it becomes easier to rotate the cap body 41 with the overcap 42 attached, and there is a risk that the cap body 41 may be rotated unintentionally. L2 / L1 could be, for example, 0.3, 0.4, 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, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, or it could be any range between any two of the numbers exemplified here.

[0138] The distance from the lower end 42h of the overcap 42 to the third region 42i where the anti-slip shape 42g is provided is preferably 3.0 to 10.0 mm, more preferably 4.0 to 8.0 mm, and even more preferably 5.0 to 7.0 mm. Specifically, this distance is, for example, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, and 10.0 mm, and may be in the range between any two of the values ​​exemplified here. If this distance is too short, the anti-slip shape 42g and the second anti-slip shape 41m2 may appear to be provided continuously, making it easy to accidentally rotate the cap body 41 when trying to rotate the overcap 42. If this distance is too long, the overcap 42 may become excessively long.

[0139] It is preferable that the outer diameter of the portion where the third region 42i is provided is smaller than the outer diameter of the portion where the second region 41n2 is provided. In this case, the anti-slip shape 42g and the second anti-slip shape 41m2 appear discontinuous, and the accidental rotation of the cap body 41 when attempting to rotate the overcap 42 is suppressed. It is preferable that the fourth region 42j from the lower end 42h to the third region 42i does not have an anti-slip shape. In this case, the anti-slip shape 42g and the second anti-slip shape 41m2 appear even more discontinuous.

[0140] <Attaching the cap 8a> As shown in Figure 24, the cap 8a can be attached to the opening 5 while supporting the first flange portion 3f1 or the second flange portion 3f2. The cap 8a is preferably of the press-fit type. With the first flange portion 3f1 or the second flange portion 3f2 supported, the cap 8a is placed over the protruding portion 4c, and when a downward force is applied to the cap 8a in this state, the engaging portion 8b overcomes the axial engaging portion 4ma, and the engaging portion 8b engages with the axial engaging portion 4ma, thereby attaching the cap 8a to the opening 5. The engaging portion 8b engages with the axial engaging portion 4ma in the axial direction and with the circumferential engaging portion 4mb in the circumferential direction. The circumferential engagement between the circumferential engaging portion 4mb and the engaging portion 8b may be a concave-concave engagement or a frictional engagement.

[0141] <Removal of inner bag 4> A method for removing the inner bag 4 from a double container 1 according to one embodiment of the present invention comprises a diameter reduction step and a removal step.

[0142] In the diameter reduction process, with the overcap 42 removed, the cap body 41 is grasped in the first region 41n1 (specifically, by pressing a gripping part such as a finger against the first region 41n1) and rotated to twist the inner bag 4 and reduce its diameter. Since the cap body 41 is engaged in the circumferential direction with the mouth portion 5 (more specifically, the protruding portion 4c) of the inner bag 4, the cap body 41 rotates relative to the outer shell 3 in such a way that the inner bag 4 twists as the cap body 41 rotates. At the body portion 6 and bottom portion 7, the inner bag 4 is less likely to rotate relative to the outer shell 3 compared to the mouth portion 5, so when the inner bag 4 is rotated relative to the outer shell 3 at the mouth portion 5, the inner bag 4 is twisted and reduced in diameter.

[0143] Since the first region 41n1 cannot be touched when the overcap 42 is attached to the cap body 41, the method of this embodiment prevents accidental rotation of the cap body 41 when rotating the overcap 42. In addition, when the overcap 42 is attached, air cannot escape from the inner bag 4, which can make it difficult to rotate the cap body 41. However, in this embodiment, it is difficult to rotate the cap body 41 without removing the overcap 42, thus motivating the user to remove the overcap 42 before rotating the cap body 41.

[0144] In the diameter reduction process, it is preferable to grip and rotate the cap body 41 in the first and second regions 41n1 and 41n2 (specifically, by pressing a gripping part such as a finger against the first and second regions 41n1 and 41n2). This has the advantage of making it easier to rotate the cap body 41.

[0145] Preferably, when the inner bag 4 is rotated during the diameter reduction process, the cam mechanism 31 provided between the inner bag 4 and the outer shell 3 causes the inner bag 4 to move in a direction away from the container body 2 as it rotates. With this configuration, by rotating the cap body 41, the inner bag 4 can be twisted and moved in a direction away from the container body 2.

[0146] In the pulling process, the reduced-diameter inner bag 4 is pulled out from the container body 2. Since the cap 8a is engaged with the inner bag 4 in the axial direction, the inner bag 4 can be pulled out from the container body 2 by pulling the cap body 41.

[0147] 1-2. Manufacturing Method of Double-Walled Container 1 The container body 2 can be manufactured by biaxial stretch blow molding of the preform 15 shown in Figures 27 to 28. The double-walled container 1 can also be manufactured by attaching a cap 8a to the container body 2.

[0148] 2. Other Embodiments - In the above embodiment, the engaging portion 8b engages with the axial engaging portion 4ma in the axial direction and with the circumferential engaging portion 4mb in the circumferential direction. However, the engaging portion 8b may not engage with the inner bag 4 in the circumferential direction, and another portion provided on the cap body 41 may be configured to engage with the circumferential engaging portion 4mb in the circumferential direction. - In the above embodiment, the circumferential engaging portion 4mb is provided below the axial engaging portion 4ma. However, the circumferential engaging portion 4mb may be provided above the axial engaging portion 4ma, and a structure in which concave and convex portions are arranged alternately in the circumferential direction may be introduced to the axial engaging portion 4ma so that the axial engaging portion 4ma also functions as the circumferential engaging portion 4mb.

[0149] 1: Double-walled container, 2: Container body, 3: Outer shell, 3a: Open end, 3a1: Base surface, 3a2: Annular projection, 3a21: Inner circumferential surface, 3a3: Inner bag opposing surface, 3a4: Apex, 3a5: Inner bag support surface, 3f1: First flange portion, 3f2: Second flange portion, 3g: Recess, 3i: Contact portion, 3j: Engaging projection, 3j1: One-sided contact surface, 3j2: Other-sided contact surface, 3j4: Base, 3j5: Base, 3j6: Connecting line, 3k: Engaging projection, 3l: Cam rail, 3m: Recess, 3m1: End portion, 3n: Inner circumferential surface, 3o: Projection, 3p: Inner tapered portion, 3q: Outer tapered portion, 3r: Part, 3s: Contact surface, 4: inner bag, 4a: first cylinder, 4b: second cylinder, 4b1: peripheral wall, 4b2: lower wall, 4b3: corner, 4b4: lower surface, 4c: protrusion, 4d: inner bag main body, 4f: Seal cylinder part, 4f1: Inner surface, 4g: Convex strip, 4g1: One side contact surface, 4g2: Other side contact surface, 4g3: Center surface, 4g4: Root, 4g5 : root, 4g6: recess, 4h: recess, 4j: outer peripheral surface, 4j1: tangent, 4j2: tangent, 4k: protrusion, 4m: engaging part, 4m3: lower surface, 4ma: Axial engaging portion, 4mb: Circumferential engaging portion, 4mb1: Convex portion, 4mb2: Convex portion, 4n: Annular convex portion, 4o: Convex strip, 4p: Movement suppressing portion, 4p1: Contact 4p2: Rear end surface, 4p3: Center surface, 4u: Undercut portion, 5: Mouth portion, 5a: Upper mouth portion, 5b: Lower mouth portion, 5b1: Base, 5c: Opening end, 5d: Flange portion, 5d1: Bottom surface, 6: Body portion, 6b: Shoulder portion, 6c: Body portion main body, 6d: Concave and concave shape, 6d1: Concave ridge, 6d2: Convex ridge, 6e: Boundary, 6f1: Grooved rib, 6f2: Grooved rib, 7: Bottom portion, 8: Mouth portion mounting member, 8a: Cap, 8b: Engaging portion, 8c: Nozzle, 8d: Discharge port, 9: Regulating portion, 13: Outer preform, 13a: Mouth portion, 13b: Body portion, 13c: Bottom portion, 13f: Opening end, 13g: Adjacent portion, 13p: Inner part Super section, 13q: outer tapered section, 14: inner preform, 14a: mouth section, 14b: body section, 14b2: part, 14c: bottom section, 14d: protruding section, 14g: convex ridge, 14h: recess, 14j: outer peripheral surface, 14k: projection, 14m: engaging section, 14p: movement restraining section, 14t: protruding seal section, 15: preform, 15a: mouth section, 15b: body section, 15c: bottom section, 15e: flange section, 15e1: bottom surface, 15f: opening end, 31: cam mechanism, 41: cap body, 41a: outer cylinder, 41a1: first cylinder, 41a2: second cylinder, 41a3: thin-walled section, 41a4: top surface, 41a5: opening end,41b: Inner cylinder, 41d: Upper wall, 41e: Valve body, 41e1: Tip, 41i: Flow hole, 41k: Male threaded part, 41m: Anti-slip shape, 41m1: First anti-slip shape, 41m2: Second anti-slip shape, 41n1: First region, 41n2: Second region, 41o: Lower end, 41p: Engaging projection, 42: Overcap, 42a: Outer cylinder, 42b: Inner cylinder, 42c: Support cylinder, 42d: Upper wall, 42e: Female threaded part, 42f: Threaded cylinder, 42g: Anti-slip Shape, 42h: lower end, 42i: third region, 42j: fourth region, 43: hinge, 44: discharge valve, 45: rail, C: central axis, C1: central axis, G: gap, G1: gap, H: height position, P: reference plane, SP1: intermediate space, SP2: external space, v: vertical line, α: angle, β: angle, δ1: inclination angle on one side, δ2: inclination angle on the other side, ε1: angle, ε2: angle, η1: angle, η2: angle, θ1: inclination angle on one side, θ2: inclination angle on the other side,

Claims

1. A double-walled container comprising a container body and a mouth attachment member, wherein the container body comprises an inner bag and an outer shell disposed to cover the inner bag, the mouth attachment member is attached to the mouth of the container body, the double-walled container is provided with an airflow restricting section, the airflow restricting section restricts the airflow between the external space of the container body and the intermediate space between the inner bag and the outer shell, and the airflow restricting section is configured to restrict the airflow through the gap between the outer shell and the mouth attachment member.

2. A double-walled container according to claim 1, wherein the airflow restricting portion is configured to suppress the leakage of air from the intermediate space when the outer shell is compressed, and to allow the flow of air from the outer space to the intermediate space when the compression of the outer shell is released.

3. A double-walled container according to claim 1, wherein the mouth attachment member is attached to a protruding portion of the inner bag that protrudes from the opening end of the outer shell.

4. A double-walled container according to claim 1, wherein the intermediate space and the external space are in communication via the airflow restricting portion through a gap between the open end of the outer shell and the inner bag.

5. A double-walled container according to any one of claims 1 to 4, wherein the airflow restricting portion comprises a valve body and a contact portion, the valve body is provided on the mouth mounting member, the contact portion is provided on the outer shell, and the airflow through the airflow restricting portion is suppressed by the contact between the valve body and the contact portion, and the airflow through the airflow restricting portion is permitted by the gap provided between the valve body and the contact portion.

6. A double-walled container according to claim 5, wherein the mouth attachment member comprises a cap body that can engage with the inner bag, the valve body is provided so as to protrude from the cap body toward the outer shell, the outer shell comprises an annular projection, the valve body is positioned radially inward of the annular projection, and the contact portion is provided on the inner circumferential surface of the annular projection.

7. A double container according to claim 6, wherein the tip of the valve body is spaced apart from the outer shell.

8. A double-walled container according to claim 5, wherein the mouth attachment member comprises a cap body that can engage with the inner bag, and the valve body is provided so as to protrude radially inward from the cap body.

9. A double-walled container according to claim 8, wherein the outer shell comprises an annular projection, and the contact portion is provided on the annular projection.

10. A method for manufacturing a double-walled container according to claim 1, wherein the container body is formed by biaxial stretch blow molding of a preform.

11. A double-walled container comprising a container body and a cap, wherein the container body comprises an inner bag and an outer shell disposed to cover the inner bag, the cap is fitted to the mouth of the container body, the cap comprises a cap body fitted to the container body and an overcap fitted to the cap body, the cap body engages with the inner bag in the circumferential direction, the cap body has an anti-slip shape on its outer surface, and at least a portion of the anti-slip shape is a first anti-slip shape provided in a first region covered by the overcap when the overcap is fitted, the double-walled container.

12. A double-walled container according to claim 11, wherein the anti-slip shape includes a second anti-slip shape provided in a second region that is not covered by the overcap when the overcap is attached.

13. A double-walled container according to claim 12, wherein the outer diameter of the portion where the second region is provided is larger than the outer diameter of the portion where the first region is provided.

14. A double-walled container according to claim 12, wherein the region provided with the second anti-slip shape has an axial length of 1.0 mm to 6.0 mm.

15. A double-walled container according to claim 12, wherein the overcap has a third anti-slip shape on its outer circumferential surface, and the distance from the lower end of the overcap to the third region where the third anti-slip shape is provided is 3.0 to 10.0 mm.

16. A double-walled container according to claim 11, wherein the direction of rotation of the overcap when removing the overcap coincides with the direction of rotation of the cap body when twisting the inner bag to reduce its diameter.

17. A double-walled container according to claim 11, wherein the first anti-slip shape is not circumferentially engaged with the overcap.

18. A method for removing an inner bag from a double-walled container, wherein the double-walled container is the double-walled container according to any one of claims 11 to 17, the method comprising a diameter reduction step and a removal step, wherein in the diameter reduction step, the inner bag is twisted and reduced in diameter by gripping and rotating the cap body in a first region with the overcap removed, and in the removal step, the reduced-diameter inner bag is pulled out from the container body.

19. A method for manufacturing a double-walled container according to any one of claims 11 to 17, wherein the container body is formed by biaxial stretch blow molding of a preform.

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