Double container

Abstract

To provide a double container reduced in power necessary for drawing out an inner bag.SOLUTION: A double container is provided which has a container body having an inner bag and an outer shell, and which is provided with an easily expandable diameter part allowing easy expansion of a diameter of a mouth of the outer shell, when drawing out the inner bag from the outer shell.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a double container. [Background technology]

[0002] Conventionally, double-layered containers having a container body with an outer shell and an inner bag have been known. For example, Patent Document 1 discloses a double-layered container formed by biaxially stretching blow molding an outer shell preform and an inner bag preform in a stacked state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-10741 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the outer shell and inner bag of such a double container are formed from different materials, or when contents remain inside the inner bag after use, it is desirable to separate the outer shell and inner bag when recycling the double container.

[0005] The outer shell and inner bag can be separated by the user by pulling the inner bag from the outer shell, but it would be desirable to reduce the force required for this separation.

[0006] The present invention has been made in view of the above circumstances, and aims to provide a double container that can reduce the force required to pull out the inner bag. [Means for solving the problem]

[0007] According to the present invention, there is provided a double container comprising a container body having an inner bag and an outer shell, wherein the mouth of the outer shell is provided with an easy-to-expand diameter portion that makes it easy to expand the diameter of the mouth of the outer shell when the inner bag is pulled out from the outer shell.

[0008] In the double container of the present invention, the opening of the outer shell is provided with the easily expandable diameter portion, so that when the inner bag is pulled out from the outer shell, the opening of the outer shell expands in diameter, thereby reducing the force required to pull out the inner bag.

[0009] Various embodiments of the present invention will be described below as examples, and the embodiments described below can be combined with each other. Preferably, in the double container described above, the easily expandable diameter portion is constituted by a slit provided in the opening portion of the outer shell. Preferably, in the double container described above, the easily expandable diameter portions are provided at a plurality of locations spaced apart in the circumferential direction at the mouth portion of the outer shell. Preferably, the double container is the above-described double container, further comprising a diameter expansion suppressing portion that suppresses the diameter expansion of the opening of the outer shell before the inner bag starts to be pulled out. Preferably, in the double container described above, the inner bag is provided with the flange, and the diameter expansion suppressing portion is formed by the flange engaging with the open end of the outer shell. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a front view of a container body 2 of a double container 1 according to one embodiment of the present invention. [Figure 2] 2 is an exploded perspective view of the vicinity of the mouth 5 of the container body 2 of FIG. 1. FIG. [Figure 3] Fig. 3A is a cross-sectional view of a plane passing through the center of the mouth portion 5 of the container body 2 in Fig. 1 and parallel to the paper surface, and Fig. 3B is an enlarged view of region B in Fig. 3A. Fig. 3C shows the state after the inner bag 4 has been slightly lifted from the state in Fig. 3A, and Fig. 3D is an enlarged view of region D in Fig. 3C. Fig. 3E shows the state after the outer shell 3 has been expanded in diameter from the state in Fig. 3C. [Figure 4] FIG. 2 is a perspective view of an inner preform 14 and an outer preform 13. [Figure 5]5A is a front view of the state in which the inner preform 14 is inserted into the outer preform 13, and FIG. 3B is a cross-sectional view of a plane passing through the central axis of the mouth portion 15a of FIG. 5A and parallel to the paper surface. DETAILED DESCRIPTION OF THE INVENTION

[0011] The following describes embodiments of the present invention. The various features shown in the following embodiments can be combined with each other. Furthermore, each feature can be an independent invention.

[0012] 1. Configuration of double container 1 <Basic configuration> As shown in FIG. 1, a double container 1 according to one embodiment of the present invention includes a container body 2.

[0013] As shown in FIG. 1, the container body 2 has a mouth 5, a body 6, and a bottom 7. The mouth 5 is a tubular (preferably cylindrical) portion with an open end 5c. The mouth 5 has an engagement portion 5a to which a mouth attachment member such as a cap or a pump can be attached. The engagement portion 5a is a male thread portion 5a1 if the mouth attachment member is a screw-type, or a ring-shaped protrusion protruding in the circumferential direction if the mouth attachment member is a stopper-type. The mouth attachment member may have a check valve (not shown). In this case, the contents can be discharged through the mouth attachment member, but outside air is prevented from entering the container body 2. The mouth 5 has a flange 5b. The flange 5b can be used to support the mouth 5 when attaching the mouth attachment member to the mouth 5.

[0014] The body 6 is disposed adjacent to the mouth 5 on the side farther from the open end 5c than the mouth 5. The body 6 has a larger outer diameter (in this specification, "outer diameter" means the circumscribed circle diameter if the cross section is not circular) than the mouth 5. The body 6 is cylindrical, and the bottom 7 is provided at the lower end of the body 6 and closes the lower end of the body 6. The body 6 has a shoulder 6b whose outer diameter increases with increasing distance from the mouth 5. The body 6 also has a body main body 6c with a substantially constant outer diameter, located closer to the bottom 7 than the shoulder 6b.

[0015] The diameter of the mouth portion 5 excluding the engaging portion 5a is, for example, 20 to 40 mm, preferably 25 to 35 mm, and specifically, for example, 20, 25, 30, 35, or 40 mm, and may be within a range between any two of the numerical values ​​exemplified here. The length of the mouth portion 5 is, for example, 15 to 35 mm, and specifically, for example, 15, 20, 25, 30, or 35 mm, and may be within a range between any two of the numerical values ​​exemplified here.

[0016] As shown in Figures 2 and 3, the container body 2 includes an inner bag 4 and an outer shell 3 arranged to cover the inner bag 4. The inner bag 4 is housed within the outer shell 3 except for the flange 4g. In the following description, the portions of the inner bag 4 that correspond to the mouth 5, body 6, and bottom 7 of the container body 2 will be referred to as the mouth 5, body 6, and bottom 7 of the inner bag 4, respectively. The same applies to the outer shell 3.

[0017] The thickness of the outer shell 3 at the center in the height direction of the container body 2 is, for example, 0.3 to 0.8 mm, preferably 0.4 to 0.5 mm. Specific examples of this thickness include 0.3, 0.4, 0.5, 0.6, 0.7, and 0.8 mm, and may be within a range between any two of the values ​​exemplified herein. The thickness of the inner bag 4 at the center in the height direction of the container body 2 is, for example, 0.10 to 0.25 mm, preferably 0.15 to 0.20 mm. Specific examples of this thickness include 0.10, 0.15, 0.20, and 0.25 mm, and may be within a range between any two of the values ​​exemplified herein. The greater the thickness of the inner bag 4, the greater the force required to pull out the inner bag 4, making the application of the present invention particularly significant.

[0018] If the mouth attachment member is provided with a check valve, the inner bag 4 contracts as the contents of the inner bag 4 are dispensed. If the mouth attachment member is not provided with a check valve, the inner bag 4 does not contract even after the contents of the inner bag 4 are dispensed, making it difficult to pull out the inner bag 4 through the mouth 5 of the outer shell 3. The present invention reduces the force required to pull out the inner bag 4 by making it easier to expand the diameter of the mouth 5 of the outer shell 3, so the significance of applying the present invention is particularly evident when the mouth attachment member is not provided with a check valve. However, even if the mouth attachment member is provided with a check valve, the expanded diameter of the mouth 5 of the outer shell 3 makes it easier to pull out the inner bag 4, so the significance of applying the present invention is also evident in this case.

[0019] <Easy-to-expand diameter section 36> The mouth 5 of the outer shell 3 is provided with an easily expandable diameter portion 36 that facilitates expansion of the diameter of the mouth 5 of the outer shell 3 when the inner bag 4 is pulled out from the outer shell 3. The easily expandable diameter portion 36 is a portion that facilitates expansion of the diameter of the mouth 5 of the outer shell 3. In this embodiment, the easily expandable diameter portion 36 is configured as a slit 37 provided in the mouth 5 of the outer shell 3, but other configurations are also possible. Examples of the easily expandable diameter portion 36 include (a) a configuration in which the slit 37 is filled with a filling material, (b) an elongated fragile portion, and (c) an elongated thin-walled portion. An example of the filling material in (a) is a material that has a lower strength than the mouth 5 of the outer shell 3. In the cases of configurations such as (a) to (c), when a radial force is applied to the mouth 5 of the outer shell 3, the easily expandable diameter portion 36 is broken or stretched, thereby expanding the diameter of the mouth 5 of the outer shell 3.

[0020] The easily expandable diameter portions 36 are preferably provided at a plurality of locations (four locations in this embodiment) spaced apart in the circumferential direction in the opening 5 of the outer shell 3. The plurality of easily expandable diameter portions 36 are preferably arranged at equal intervals in the circumferential direction. The number of easily expandable diameter portions 36 is, for example, 1 to 8, preferably 2 to 6, and specifically, for example, 1, 2, 3, 4, 5, 6, 7, or 8, and may be within a range between any two of the values ​​exemplified here. The width of the slit 37 is, for example, 0 to 1 mm, and specifically, for example, 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0 mm, and may be within a range between any two of the values ​​exemplified here. When the width of the slit 37 is 0 mm, the slit 37 is formed by a cut formed in the outer shell 3. By providing easily expandable diameter portion 36, the diameter of mouth portion 5 of outer shell 3 is easily expanded when inner bag 4 is pulled out from outer shell 3, and the force required to pull out inner bag 4 is reduced.

[0021] The easily expandable diameter portion 36 is preferably provided so as to straddle the mouth portion 5 and the shoulder portion 6b of the outer shell 3. In this case, the mouth portion 5 of the outer shell 3 is easily expanded in diameter.

[0022] Incidentally, if the opening 5 of the outer shell 3 expands in diameter before the contents of the double container 1 are used up, there is a risk that the usability and aesthetics of the double container 1 will deteriorate. Therefore, as shown in FIGS. 3A and 3B , the double container 1 is provided with a diameter expansion suppressing portion 38 that suppresses the diameter expansion of the opening 5 of the outer shell 3 before starting to pull out the inner bag 4. The configuration of the diameter expansion suppressing portion 38 is not particularly limited as long as it suppresses the diameter expansion of the opening 5 of the outer shell 3. In this embodiment, the diameter expansion suppressing portion 38 is configured by engaging the flange 4g of the inner bag 4 with the open end 3a of the outer shell 3.

[0023] The flange 4g is a portion that extends radially outward at the open end 4h of the inner bag 4 and is preferably formed in an annular shape. The flange 4g abuts against the open end 3a. A groove 4g1, preferably an annular groove, is provided below the flange 4g, and an insertion portion 3g formed by thinning the outer shell 3 is provided at the open end 3a of the outer shell 3. By inserting the insertion portion 3g into the groove 4g1, the flange 4g of the inner bag 4 engages with the open end 3a of the outer shell 3.

[0024] To remove the inner bag 4, first, as shown in FIGS. 3C and 3D, the inner bag 4 is slightly lifted to remove the insertion portion 3g from the groove 4g1. This disengages the flange 4g from the open end 3a, allowing the diameter of the mouth portion 5 of the outer shell 3 to expand. The distance by which the inner bag 4 is lifted is, for example, 0.1 to 3 mm, specifically, for example, 0.1, 0.3, 0.5, 1.0, 1.5, 2.0, 2.5, or 3.0 mm, and may be within a range between any two of the values ​​exemplified here. The configuration for lifting the inner bag 4 is not particularly limited. The inner bag 4 may be lifted by manually lifting the flange 4g, by lifting a pull tab attached to the flange 4g, or by using a mouth attachment member. A tapered surface 3h is provided adjacent to the insertion portion 3g, and a gap 39 is formed between the tapered surface 3h and the underside of the flange 4g. The inner bag 4 can be easily lifted by hooking a finger on the flange 4g in the gap 39.

[0025] When lifting the inner bag 4 using the mouth attachment member, for example, the screw-type mouth attachment member is screwed into the engagement portion 5a and engaged with the inner bag 4, and in this state, the mouth attachment member is rotated in the direction of removing it from the engagement portion 5a, thereby lifting the inner bag 4. In this case, the diameter of the inner bag 4 is reduced by twisting, making it even easier to pull out the inner bag 4.

[0026] 3E, the diameter of the mouth 5 of the outer shell 3 is expanded, and the outer shell 3 is pulled out from the inner bag 4. The diameter of the mouth 5 of the outer shell 3 may be expanded by the inner bag 4 applying a radially outward force to the mouth 5 of the outer shell 3 when the inner bag 4 is pulled out, or may be expanded using a separate jig or the like.

[0027] Incidentally, when the inner bag 4 contracts as the contents of the inner bag 4 are discharged, it is preferable to introduce outside air into the intermediate space between the outer shell 3 and the inner bag 4 to prevent the outer shell 3 from contracting. If the easily expandable diameter portion 36 has an air-permeable configuration such as the slit 37, it is possible to introduce outside air into the intermediate space through the easily expandable diameter portion 36. If the easily expandable diameter portion 36 does not have an air-permeable configuration, it is preferable to provide an outside air inlet hole for introducing outside air into the intermediate space between the outer shell 3 and the inner bag 4. The outside air inlet hole can be provided, for example, in the body or the bottom.

[0028] 2. Manufacturing method of double container 1 As shown in Figures 4 and 5, the container body 2 can be formed by heating and biaxially stretching blow molding a preform 15 formed by covering an inner preform 14 that will become the inner bag 4 with an outer preform 13 that will become the outer shell 3.

[0029] <Configuration of inner preform 14, outer preform 13, and preform 15> As shown in Figure 4, the inner preform 14 is cylindrical and has a bottom, a mouth portion 14a, a body portion 14b, and a bottom portion 14c. A flange 14g is provided at the open end of the mouth portion 14a. The flange 14g does not deform during molding and remains in its original shape to become the flange 4g. Therefore, the matters described for the flange 4g also apply to the flange 14g. The bottom portion 14c is provided so as to close the lower end of the body portion 14b. A positioning pin 14c1 is provided on the bottom portion 14c.

[0030] As shown in Fig. 4, the outer preform 13 is cylindrical with a bottom and includes a mouth portion 13a, a body portion 13b, and a bottom portion 13c. The bottom portion 13c is provided so as to close the lower end of the body portion 13b. A positioning hole 13i (shown in Fig. 5B) is provided in the bottom portion 13c. A slit 13g is provided in the outer preform 13 so as to span the mouth portion 13a and the body portion 13b. The slit 13g becomes the slit 37 after molding.

[0031] As shown in Figure 5, when forming the preform 15, the flange 14g is brought into contact with the open end of the mouth portion 13a, and the positioning pin 14c1 is inserted into the positioning hole. This positions the inner preform 14 and the outer preform 13 relative to each other. In this state, the mouth portion 14a faces the mouth portion 13a, and the body portion 14b faces the body portion 13b. As shown in Figure 5B, the flange 14g engages with the open end 13h of the outer preform 13. This prevents the mouth portion 13a of the outer preform 13 from expanding in diameter during molding.

[0032] 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. The body portion 15b and the bottom portion 15c are mainly stretched in the biaxial stretch blow molding.

[0033] <Materials and manufacturing methods for inner preform 14, outer preform 13, and preform 15> The inner preform 14 and the outer preform 13 can be formed by direct blow molding, injection molding, or the like using thermoplastic resins such as polyester (e.g., PET) or polyolefin (e.g., polypropylene, polyethylene). The inner preform is preferably made of a material with a higher molding shrinkage rate than the outer preform. In this case, a gap is formed between the outer shell 3 and the inner bag 4 due to molding shrinkage, making it easier to introduce outside air into the intermediate space between the outer shell 3 and the inner bag 4.

[0034] In one example, the inner preform 14 is made of polyolefin (e.g., polypropylene), and the outer preform 13 is made of PET. Polyolefin has a larger molding shrinkage rate than PET, so using such a resin configuration makes it easier for a gap to form between the outer shell 3 and the inner bag 4. Furthermore, by making the inner preform 14 and the outer preform 13 from different materials, welding to each other during blow molding is suppressed.

[0035] The inner preform 14 is preferably formed by direct blow molding. Direct blow molding (blow molding using a molten cylindrical parison) makes it easy to form the inner preform 14 with a laminated structure. The outer preform 13 is preferably formed by injection molding.

[0036] The preform 15 may be formed by combining the inner preform 14 and the outer preform 13 after they have been formed separately, or may be formed by two-color molding. [Explanation of symbols]

[0037] 1:Double container 2: Container body 3: Outer shell 3a: Open end 3g :Insertion part 3h: Tapered surface 4: Inner bag 4g: flange 4g1 : Groove 4h: Open end 5: Mouth 5a: Engagement part 5a1: Male thread 5b: Flange 5c: Open end 6: Body 6b:Shoulder 6c: Body 7: Bottom 13: Outer preform 13a: Mouth 13b: Torso 13c: Bottom 13g: Slit 13h: Open end 13i: Positioning hole 14: Inner preform 14a: Mouth 14b: Torso 14c: Bottom 14c1: Locating pin 14g: Flange 15: Preform 15a: Mouth 15b: Body 15c: bottom 36: Easy-to-expand diameter section 37: Slit 38: Diameter expansion suppression part 39: Gap

Claims

1. A double container comprising a container body having an inner bag and an outer shell, The double container has an easily expandable diameter portion at the mouth of the outer shell, which facilitates the expansion of the diameter of the mouth of the outer shell when the inner bag is pulled out from the outer shell.

2. The double container according to claim 1, The double container, wherein the easily expandable diameter portion is constituted by a slit provided in the mouth portion of the outer shell.

3. The double container according to claim 1 or claim 2, The double container has a plurality of easily expandable diameter portions provided at circumferentially spaced locations in the mouth portion of the outer shell.

4. The double container according to any one of claims 1 to 3, A double container provided with a diameter expansion suppressing portion that suppresses the diameter expansion of the opening portion of the outer shell before the inner bag starts to be pulled out.

5. The double container according to claim 4, the inner bag includes a flange; The double container, wherein the diameter expansion suppression portion is formed by the flange engaging with the open end of the outer shell.

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