Double-walled container and method for manufacturing the same

Abstract

To provide a double-walled container that can reduce at least one of the effort required for manufacturing the double-walled container and the number of parts. [Solution] According to the present invention, a double-walled container is provided, 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. The double-walled container of the present invention has excellent recyclability and is therefore suitable for use in the manufacture of recycled materials.

Description

Technical Field

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

Background Art

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

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] 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, so that the compressive force applied to the outer shell is transmitted to the inner bag, and the outer shell is configured to return to its original shape when the compressive force is removed.

[0005] 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.

[0006] 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.

Means for Solving the Problems

[0007] According to the present disclosure, the following inventions are provided. [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. A double-walled container as described in [2][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. A double container according to [3] [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. A double-walled container according to any one of [4][1] to [3], 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. A double-walled container according to any one of [5][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. A double container as described in [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 as described in [7][6], wherein the tip of the valve body is spaced apart from the outer shell. A double container as described in [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-walled container as described in [9][8], wherein the outer shell is provided with an annular projection, and the contact portion is provided on the annular projection. A method for manufacturing a double-walled container according to any one of

[10] [1] to [9], wherein the container body is formed by biaxial stretch blow molding of a preform. [Effects of the Invention]

[0008] 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. Therefore, 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, and thus the number of parts required to manufacture the double-walled container can be reduced. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view of a double-walled container 1 according to the first embodiment 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. [Figure 2] Figure 1 is an exploded perspective view of the double container 1. [Figure 3] Figures 3A and 3B are the plan view and front view, respectively, of the container body 2 shown in Figure 2. [Figure 4] Figure 4A is a longitudinal cross-sectional view of the double container 1 in Figure 1 with the overcap 42 closed. Figure 4B is an enlarged view of region B in Figure 4A. [Figure 5] Figure 4A is an exploded view with the overcap 42 slightly open. [Figure 6] FIG. 6A is an enlarged view of region A in FIG. 5. FIG. 6B is a diagram corresponding to FIG. 6A in the reference example. [Figure 7] It is an exploded view of the container body 2 in FIG. 5. [Figure 8] FIG. 8A is a cross-sectional view taken along line A-A in FIG. 5. FIG. 8B is an enlarged view of region B in FIG. 8A. [Figure 9] It is a cross-sectional view taken along line B-B in FIG. 5. [Figure 10] FIG. 10A is a cross-sectional view taken along line C-C in FIG. 5. FIG. 10B is an enlarged view of region C in FIG. 10A. FIG. 10C is an enlarged view of region D in FIG. 10B. [Figure 11] It is an exploded perspective view of the container body 2 in FIG. 2. [Figure 12] FIG. 12A is a front view of the inner bag 4. FIG. 12B is a cross-sectional view taken along line D-D in FIG. 12A. [Figure 13] FIG. 13A is a cross-sectional view of the container body 2 immediately after releasing the pressing of the body portion 6. FIG. 13B is an enlarged view of region E in FIG. 13A. [Figure 14] It is a perspective view showing a state in which the inner preform 14 and the outer preform 13 are separated. [Figure 15] It is a perspective view of the preform 15 formed by covering the inner preform 14 with the outer preform 13. [Figure 16] It is a front view showing a state in which the inner preform 14 is supported by a pair of rails 45. [Figure 17] It is a longitudinal sectional view of the preform 15. [Figure 18] It is an enlarged view corresponding to FIG. 4B of the second embodiment. [[ID=३९]] [Figure 19] It is an enlarged view showing a state when the valve body 41e is displaced in a direction away from the contact portion 3i.

Mode for Carrying Out the Invention

[0010] Embodiments of this disclosure will be described below with reference to the drawings. The various features shown in the embodiments below can be combined with each other. Furthermore, each feature constitutes an independent invention. In addition, any elements in the embodiments below that are not defined in the claims are optional 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".

[0011] 1. First Embodiment The double-walled container 1 of the first embodiment of the present invention will be described with reference to Figures 1 to 17. 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. Unless otherwise specified, "clockwise" and "counterclockwise" refer to directions viewed from the top of the double-walled container 1.

[0012] 1-1. Composition of Double Container 1 As shown in Figure 1, the double-walled container 1 of the first embodiment of the present invention 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.

[0013] <Configuration of container body 2> As shown in Figures 2 and 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 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 and 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.

[0014] 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.

[0015] 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.

[0016] The shoulder portion 6b is provided with a convex-concave shape 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 convex-concave shape 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.

[0017] 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.

[0018] The fuselage body 6c 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 fuselage body 6c is increased by providing the groove-shaped ribs 6f1 and 6f2.

[0019] 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.

[0020] <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.

[0021] 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.

[0022] The angle α of the peripheral wall 4b1 relative 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.

[0023] 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.

[0024] 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.

[0025] 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. If, as in this embodiment, an outside air intake hole for introducing air into the intermediate space SP1 is not provided in the outer shell 3, 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.

[0026] 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 technical significance 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.

[0027] <Details of the opening 5 of the outer shell 3> As shown in Figure 4, the open end 3a of the outer shell 3 is provided with a base surface 3a1, an annular projection 3a2, and an inner bag opposing 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 open end 41a1 of the outer cylinder 41a of the mouth attachment member 8, and the annular projection 3a2 protrudes outward from the valve body 41e (described later) of the mouth attachment 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 open end 41a1. In this case, the entry of foreign matter is further suppressed.

[0028] 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.

[0029] 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. It is preferable that 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.

[0030] <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 portion 4u when the inner bag 4 is pulled out of the container body 2. The undercut portion 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 portion 4u, the greater the force required to pull out the inner bag 4.

[0031] 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.

[0032] 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 portion of the lower opening 5b. In this case, the inner tapered portion 3p is more easily formed.

[0033] 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, respectively, 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.

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

[0035] 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 greater (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 present invention becomes. 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.

[0036] <Details of 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 ridge 4g that protrudes radially outward. As shown in Figure 12A, the lower surface of the ridge 4g is inclined so that it approaches the open end 5c as it moves counterclockwise.

[0037] 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 between any two of the values ​​exemplified here.

[0038] 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, since the protrusion 4g is positioned adjacent to the recess 4h, 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.

[0039] As shown in Figure 11, the inner circumferential surface of the outer shell 3 is provided with a recessed ridge 3m that can engage with a convex ridge 4g. Preferably, the recessed ridge 3m is provided at the end of the cam rail 3l. The upper surface of the cam rail 3l is inclined so that it approaches the open end 3a as it moves in the counterclockwise direction. The convex ridge 4g and the recessed ridge 3m are configured to be able to engage by relative rotation of the inner bag 4 and the outer shell 3 in one direction, and to be able to disengage by relative rotation of the inner bag 4 and the outer shell 3 in the other direction.

[0040] Multiple cam rails 3l are provided on the inner circumferential surface of the outer shell 3, and these multiple cam rails 3l are offset from each other in the circumferential direction. In this embodiment, two cam rails 3l are arranged offset by 180 degrees in the circumferential direction. Furthermore, 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, between 90 and 360 degrees, and preferably between 120 and 240 degrees (180 degrees in this embodiment). These angles are specifically, 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, and 360 degrees, and may also be within a range between any two of the values ​​exemplified here.

[0041] It is preferable that the recessed groove 3m is provided on each cam rail 3l. The explanation of the angle at which the recessed groove 3m extends is the same as the explanation of the angle for the convex groove 4g described above.

[0042] Before the inner bag 4 is pulled out of the container body 2, the lower surface of the convex ridge 4g is in contact with the upper surface of the cam rail 3l within the concave ridge 3m. The convex ridge 4g and the cam rail 3l constitute the cam mechanism 31. When the inner bag 4 is rotated counterclockwise relative to the outer shell 3, the inner bag 4 is displaced in a direction that allows it to be pulled 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 standard screw.

[0043] <Details of the rotation restriction structure> The container body 2 is preferably provided with a rotation restricting structure that restricts the relative rotation of the inner bag 4 and the outer shell 3. Examples of this rotation restricting structure include a structure that increases the frictional force between the inner bag 4 and the outer shell 3, and a structure that causes the inner bag 4 and the outer shell 3 to engage with each other in the circumferential direction. In this embodiment, as shown in Figures 10 to 11, the outer shell 3 is provided with an engaging projection 3j on its inner circumferential surface 3n that protrudes radially inward. The engaging projection 3j is preferably arranged along the cam rail 3l, and more preferably arranged within or adjacent to the groove 3m.

[0044] As shown in Figure 10, the protrusion 4g comprises a one-sided contact surface 4g1 that abuts against the engaging projection 3j when rotated relative to it in one direction (i.e., the engagement direction), a other-sided contact surface 4g2 that abuts against the engaging projection 3j when rotated relative to it in the other direction (i.e., the disengagement direction), and a central surface 4g3 between the one-sided contact surface 4g1 and the other-sided contact surface 4g2. The one-sided contact surface 4g1 and the other-sided contact surface 4g2 are end faces located at the longitudinal ends of the protrusion 4g. The central surface 4g3 has a similar shape to the part 3r of the outer shell 3 that the central surface 4g3 opposes. The central surface 4g3 does not have any protrusions that extend from it. On the central surface 4g3, the protrusion height of the protrusion 4g from the outer peripheral surface 4j is constant. From the longitudinal center of the convex ridge 4g toward the bases 4g4 and 4g5 at both ends of the convex ridge 4g in the longitudinal direction, the height of the convex ridge 4g decreases monotonically.

[0045] In a configuration where a separate projection is provided on the central surface 4g3 of the protruding ridge 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 a separate projection on the central surface 4g3, the end face at the longitudinal end of the protruding ridge 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 ridge 4g is less likely to become thin compared to the case where a separate 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 ridge 4g may be hollow or solid, but when the protruding ridge 4g is hollow, the technical significance of abutting the end face at the longitudinal end of the protruding ridge 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.

[0046] The other-side contact surface 4g2 has a other-side inclination angle θ2, which is the inclination angle 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 convex portion 3j, it may easily deform, resulting in insufficient restriction of relative rotation.

[0047] The inclination angle θ1 on one side, which is the angle of inclination of the outer peripheral surface 4j with respect to the tangent 4j1 at the base 4g5 of the contact surface 4g1 on one side, 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 (44 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 a range between any two of the values ​​exemplified here.

[0048] The engaging projection 3j comprises a one-sided contact surface 3j1 that abuts against the projection 4g when rotated relative to it in one direction (i.e., the engagement direction), and a other-sided contact surface 3j2 that abuts against the projection 4g when rotated relative to it in the other direction (i.e., the disengagement direction). The one-sided contact surface 3j1 abuts against the one-sided contact surface 4g1, and the other-sided contact surface 3j2 abuts against the other-sided contact surface 4g2.

[0049] 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.

[0050] 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 11 and 12B, the projection 4k is positioned further away from the convex ridge 4g than the engaging projection 3j, with the convex ridge 4g engaged with the concave 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.

[0051] 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, which prevents the projection 4g from falling off the cam rail 3l.

[0052] 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.

[0053] 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 that rotates in the other direction, and the projection 4k is the downstream portion of the convex ridge 4o that rotates in the other direction.

[0054] 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. In addition, 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.

[0055] In this embodiment, the inner bag 4 is provided with a movement-restricting portion 4p on its outer 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.

[0056] 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 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.

[0057] 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.

[0058] 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.

[0059] 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. Therefore, even if you try 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 catches on 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).

[0060] 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 capable of preventing 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.

[0061] <Detailed configuration of the mouth attachment member 8> As shown in Figures 4 and 5, it is preferable that the mouth attachment member 8 has a discharge port 8d for discharging the contents of the inner bag 4. It is also preferable that the mouth attachment member 8 is equipped with a nozzle 8c.

[0062] The cap 8a preferably comprises a cap body 41 and an overcap 42. The cap body 41 is configured to engage with a protrusion 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.

[0063] 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 passages of the inner cylinder 41b and the nozzle 8c are 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.

[0064] 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.

[0065] 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.

[0066] 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. When the overcap 42 is closed, the discharge valve 44 is located below the lower end of the inner cylinder 42b.

[0067] 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.

[0068] <Details of Airflow Restriction 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 between the outer shell 3 and the mouth attachment member 8.

[0069] 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 suppresses air leakage from 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 discharged 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 no outside air enters the inner bag 4, and the inner bag 4 remains contracted.

[0070] 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 air flow restrictor 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 air flow restrictor 9, and the outer shell 3 is quickly restored to its original shape.

[0071] Furthermore, 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] The thickness of the valve body 41e is, for example, 0.1 mm to 1.0 mm (0.4 mm in this embodiment), and 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, and 1.00 mm, and may be in the range between any two of the values ​​exemplified here.

[0076] 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.

[0077] 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 41a1 of the cap body 41.

[0078] 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 protrusion 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 comes into contact with the inner circumferential surface 3a21, thereby making the intermediate space SP1 a sealed space.

[0079] 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 of forming the valve body 41e is not particularly limited.

[0080] <Attachment of mouth attachment member 8> As shown in Figure 5, the mouth mounting member 8 can be attached to the mouth 5 while supporting the projection 3o or flange portion 5d. The mouth mounting member 8 is preferably of the plug type, and while supporting the projection 3o or flange portion 5d, the mouth mounting member 8 is placed over the projection 4c, and when a downward force is applied to the mouth mounting 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 mounting 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.

[0081] <Pulling out inner bag 4> The mouth attachment member 8 is engaged with the protrusion 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. Furthermore, a cam mechanism 31 provided between the inner bag 4 and the outer shell 3 is configured to move the inner bag 4 in a direction that allows it to detach from the container body 2 as it rotates.

[0082] 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.

[0083] 1-2. Manufacturing method of double-walled container 1 The container body 2 can be manufactured by biaxial stretch blow molding the preform 15 shown in Figure 15. Furthermore, the double-walled container 1 can be manufactured by attaching the mouth attachment member 8 to the container body 2.

[0084] <Composition: 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.

[0085] 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 protrusion 14d is provided on the mouth portion 14a. As shown in Figures 14 to 15, the protrusion 14d is a portion that protrudes from the open end 13f of the outer preform 13 in the preform 15. The protrusion 14d remains in its original shape during molding and becomes the protrusion 4c. The protrusion 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.

[0086] Furthermore, the inner preform 14 has a recess 14h in the portion facing the outer preform 13. Preferably, the recess 14h is formed by recessing the inner preform 14 so that it 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.

[0087] 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.

[0088] 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 bottom surface 15e1 of the outer preform 13, on the bottom surface 13c side of the outer preform 13, where the inner diameter of the outer preform 13 decreases toward the bottom surface 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 surface 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.

[0089] 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, then 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.

[0090] 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.

[0091] 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.

[0092] 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, 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] <Materials and manufacturing methods for 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 polyolefins (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.

[0097] <Biaxial stretch blow molding process> The biaxial stretch blow molding process for preform 15 includes, in one example, a heating step and a stretching step. Each step is described below.

[0098] <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 another example, the heater consists of multiple rod-shaped heaters arranged along the side of the preform 15, but other configurations are also possible.

[0099] <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 step and a second stretching step.

[0100] <First and Second Extension Processes> In the first stretching step, the preform 15 is stretched along the first axis (i.e., the longitudinal direction). The first axis is, for example, parallel to the central axis C of the mouth 5. In the second stretching step, the preform 15 is stretched (i.e., expanded) in the second axis (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.

[0101] 2. Second Embodiment The double-walled container 1 according to the second embodiment will be described using Figure 18. The second embodiment is the same as the first embodiment except for the configuration of the airflow restricting section 9, and the contents described in the first embodiment are applicable to this embodiment as long as they do not contradict the intent of the first embodiment. The differences will be mainly described below, and redundant explanations will be omitted as appropriate.

[0102] 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 to move away from the bottom of the outer shell 3 from the radial 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.

[0103] 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.

[0104] 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). This creates a gap G between the valve body 41e and the contact portion 3i, allowing air to flow 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.

[0105] 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.

[0106] 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.

[0107] 3. Other Embodiments In the above embodiment, the direction of relative rotation of each component may be reversed. 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 the right-hand screw is rotated in the loosening direction, 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 the left-hand screw is rotated in the loosening direction. 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 is shaped to extend in a clockwise inclination from the boundary 6e toward the base 5b1 of the mouth 5.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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, it is possible to color only the inner bag 4 of the outer shell 3. 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. [Explanation of Symbols]

[0112] 1:Double container 2: Container body 3: Outer shell 3a: Open end 3a1: Base surface 3a2: Annular protrusion 3a21: Inner surface 3a3: Inner bag opposing surface 3a4: Vertex 3g: recess 3i: Contact part 3j: Engagement convex part 3j1: One-sided contact surface 3j2: Other side contact surface 3j4 : Root 3j5 : Root 3j6: Connecting line 3L: Cam Rail 3m: Concave 3m1: Edge 3n: Inner surface 3o: Projection 3p: Inner tapered portion 3q: Outer tapered portion 3r: Portion 3s: Contact surface 4: Inner bag 4a: First cylinder 4b: Second cylinder 4b1: Peripheral wall 4b2: Bottom wall 4b3: Corner portion 4b4: Bottom surface 4c: Protrusion 4d: Inner bag body 4f: Seal cylinder portion 4f1: Inner surface 4g: Rib 4g1: One - side contact surface 4g2: The other - side contact surface 4g3: Central surface 4g4: Root 4g5: Root 4g6: Concave portion 4h: Concave portion 4j: Outer peripheral surface 4j1: Tangent line 4j2: Tangent line 4k: Protrusion 4m: Engaging portion 4m3: Bottom surface 4ma: Axial direction engaging portion 4mb: Circumferential direction engaging portion 4mb1: Convex portion 4mb2: Convex portion 4n: Annular convex portion 4o: Rib 4p: Movement - inhibiting portion 4p1: Contact surface 4p2: Rear end surface 4p3: Central surface 4u: Undercut portion 5: Mouth portion 5a: Upper mouth portion 5b: Lower mouth portion 5b1: Root 5c: Opening end 5d: Flange portion 5d1: Bottom surface 6: Torso 6b:Shoulder 6c: Torso body 6d: Uneven shape 6d1: Concave line 6d2: convex stripe 6e :boundary 6f1: Grooved rib 6f2: Grooved rib 7: Bottom 8: Mouthpiece mounting member 8a: Cap 8b: Engagement part 8c: Nozzle 8d:Discharge port 9: Regulatory Department 13: External preform 13a: Mouth 13b: Torso 13c: Bottom 13f: Open end 13g: Adjacent parts 13p: Inner tapered section 13q: Outer tapered section 14: Internal preform 14a: Mouth 14b: Torso 14b2 : Part 14c: Bottom 14d:Protrusion 14g: Convex strip 14h: recess 14j: Outer surface 14k: Protrusion 14m: Engagement part 14p: Movement suppression part 14t: Protruding seal section 15: Preform 15a: Mouth 15b: Torso 15c: bottom 15e: Flange section 15e1: Bottom surface 15f: Open end 31: Cam mechanism 41: Cap body 41a: Outer cylinder 41a1: Open end 41b: Inner cylinder 41d: Upper wall 41e: Valve body 41e1:Tip 41i :Flow hole 42: Overcap 42a: Outer cylinder 42b: Inner cylinder 42d: Upper wall 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: One-sided tilt angle δ2: Inclination angle on the other side θ1: One-sided tilt angle θ2:Other side inclination angle

Claims

1. A double-walled container comprising a container body and a mouth attachment member, The container body comprises an inner bag and an outer shell positioned 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. A double-walled container, wherein the airflow restricting portion is configured to restrict the flow of air through the gap between the outer shell and the mouth mounting member.

2. A double-walled container according to claim 1, A double-walled container wherein the airflow restricting section 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, The mouth attachment member is attached to a protruding portion of the inner bag that extends from the open end of the outer shell, forming a double-walled container.

4. A double-walled container according to claim 1, A double-walled container in which 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, The aforementioned airflow restricting section 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, A double container configured such that the flow of air through the airflow restricting portion is suppressed when the valve body and the contact portion come into contact, and the flow of air through the airflow restricting portion is permitted when the gap is provided between the valve body and the contact portion.

6. A double container according to claim 5, 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 is provided with an annular protrusion, The valve body is positioned radially inward of the annular protrusion, The contact portion is a double container provided on the inner circumferential surface of the annular protrusion.

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

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

9. A double container according to claim 8, The outer shell is provided with an annular protrusion, The contact portion is a double container provided on the annular protrusion.

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

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