Double container

Abstract

To provide a double container capable of preventing an inner container from being excessively crushed at a trunk part so as to be narrowed.SOLUTION: According to a double container 1 constituted from an outer container 4 and an inner container 5, the double container 1 continuously comprises a mouth 1a, a trunk part 1b, and a bottom part 1c in this order. The bottom part 1c comprises a central recess 1c1 recessed upward. An outer peripheral wall part 14 of the central recess 1c1 is constituted from a body outer peripheral wall 14a formed from the outer container 4, and a sub outer peripheral wall 14b coming into contact with an outer peripheral face of the body outer peripheral wall 14a formed from the inner container 5. The outer peripheral wall part 14 comprises a screw shape part 16 in shape along a screw thread 17a spirally extending downward to a lower end of the outer peripheral wall part 14.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] There is known a double container having a mouth part, a body part, and a bottom part connected in this order, composed of an outer container and an inner container, and when the contents of the inner container are discharged, outside air can be introduced between the outer container and the inner container by the inner container peeling off from the outer container in the body part (see, for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the case of the double container as described above, for example, when the contents accommodated in the inner space of the inner container are discharged through the check valve of the discharge cap with the discharge cap having a check valve attached to the mouth part, the outside air that replaces the discharged contents in the double container is introduced not into the inner space but between the outer container and the inner container. Therefore, the contact between the contents in the inner space and the outside air can be suppressed, and the quality of the contents can be maintained well. However, if the inner container peels off from the outer container at the bottom, the inner container may be excessively crushed so as to be constricted at the body part, and the contents remaining on the bottom side of the constricted part may not be discharged. Further, not only in the case of a double container of a type in which the inner container peels off from the outer container and outside air is introduced as the contents are discharged, but also in the case of a double container that can separate the inner container from the outer container, for example, at the time of separate disposal, the inner container may peel off unexpectedly, which may inhibit the discharge of the contents.

[0005] Therefore, an object of the present invention is to provide a double container that can suppress excessive crushing so that the inner container is constricted in the body portion.

Means for Solving the Problems

[0006] One aspect of the present invention is as follows.

[0007] [1] A double container having a mouth portion, a body portion, and a bottom portion connected in this order, and composed of an outer container and an inner container, wherein the bottom portion has a central concave portion that is concave upward, the outer peripheral wall portion of the central concave portion is composed of a main body outer peripheral wall formed by the outer container and a sub-outer peripheral wall formed by the inner container and contacting the outer peripheral surface of the main body outer peripheral wall, the outer peripheral wall portion has a screw-shaped portion having a shape along a thread that spirally extends downward to the lower end of the outer peripheral wall portion, the double container.

[0008] [2] The outer diameter of the screw-shaped portion is equal to or less than the inner diameter of the outer container at the mouth portion, the double container according to [1].

[0009] [3] The inner container has a screwing portion that can be screwed so as to rise while rotating in one circumferential direction with respect to the outer container at the mouth portion, in the screw-shaped portion, the sub-outer peripheral wall can be screwed off from the main body outer peripheral wall by rotation in one circumferential direction, the double container according to [1] or [2].

[0010] [4] The double container according to any one of [1] to [3], and a discharge cap having a check valve, attached to the mouth portion, and capable of discharging the contents accommodated in the inner space of the inner container through the check valve, when the double container discharges the contents, external air can be introduced between the outer container and the inner container by the inner container peeling off from the outer container in the body portion, The discharge cap has a co-rotating engagement portion that is co-rotatably engaged with the inner container in the circumferential direction on one side at the mouth portion, and is attached to the inner container by screwing on. The inner container has a screwing portion that is screwed to the outer container at the mouth portion so as to be able to rise while rotating in the circumferential direction on one side, and is a discharge container.

Effects of the Invention

[0011] According to the present invention, it is possible to provide a double container that can suppress the inner container from being excessively crushed so as to be constricted in the body portion.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be illustrated and described with reference to the drawings.

[0014] As shown in FIGS. 1 to 4, in one embodiment of the present invention, the discharge container 3 has a double container 1 and a discharge cap 2. The double container 1 has a mouth portion 1a, a body portion 1b, and a bottom portion 1c connected in this order, and is composed of an outer container 4 and an inner container 5. The discharge cap 2 has a check valve 6, is attached to the mouth portion 1a, and can discharge the content (not shown) accommodated in the internal space S of the inner container 5 through the check valve 6. When the content is discharged, the double container 1 can introduce outside air between the outer container 4 and the inner container 5 through the outside air inlet 1d by the inner container 5 peeling off from the outer container 4 at the body portion 1b. When the outer container 4 is squeezed, the outer container 4 and the inner container 5 are squeezed and deformed (volume reduction), and the outer container 4 can be restored, but the inner container 5 cannot be restored because it is blocked by the check valve 6 at the mouth portion 1a. Therefore, when the outer container 4 is restored while the inner container 5 remains reduced in volume, the gap between the inner container 5 and the outer container 4 is enlarged, and this gap becomes a reduced pressure state, so outside air is introduced into the gap.

[0015] In addition, the "peeling" in the present application includes not only the case where the inner container 5 and the outer container 4 are separated from a pseudo-adhesive state with almost no adhesive force, but also the case where the inner container 5 and the outer container 4 are separated from a contact state without adhesive force. The outside air inlet 1d is composed of a plurality of through holes in this embodiment, but is not limited thereto. Also, the outside air inlet 1d is provided at the mouth portion 1a in this embodiment, but is not limited thereto, and may be provided at the body portion 1b, for example. The content is not particularly limited, and is a liquid, for example.

[0016] The double container 1 is formed by biaxially stretching and blow molding a preform assembly having a double structure in which an outer preform (not shown) formed by injection molding a polyethylene terephthalate (PET) resin capable of biaxial stretching and an inner preform (not shown) formed by injection molding a polypropylene (PP) resin (regardless of whether it is a homopolymer, a random copolymer, or a block copolymer) are combined. The outer preform corresponds to the outer container 4, the inner preform corresponds to the inner container 5, and the portions corresponding to the body portion 1b and the bottom portion 1c in the preform assembly are stretched in the vertical direction and the radial direction by biaxially stretching and blow molding, so that the body portion 1b and the bottom portion 1c of the double container 1 are formed.

[0017] Examples of the biaxially stretchable polyethylene terephthalate resin include homopolymer PET, etc., but other PETs such as IPA (isophthalic acid) modified PET or CHDM modified PET may also be used.

[0018] The outer preform is not limited to the polyethylene terephthalate resin, and may be formed of other resin materials such as, for example, polypropylene (PP) resin or polyethylene (PE) resin. The inner preform is not limited to the polypropylene resin, and may be appropriately formed by selecting a material that allows the inner container 5 to be peeled off from the outer container 4. For example, it may be formed of polyethylene (PE) resin or biaxially stretchable polyethylene terephthalate resin. The inner preform and the outer preform may be made of different materials or the same material. The outer preform and the inner preform are not limited to single-layer structures, respectively, and may have a multi-layer structure including one or more functional layers for improving functions such as barrier properties in addition to the main material layer.

[0019] In the present embodiment, the vertical direction is the direction along the central axis O of the mouth portion 1a, the upward direction is the direction from the bottom portion 1c toward the mouth portion 1a, the downward direction is the opposite direction, the radial direction is the direction orthogonal to the central axis O, and the circumferential direction is the direction around the central axis O.

[0020] The mouth portion 1a of the double container 1 has a cylindrical shape, and the body portion 1b has a shoulder portion 1b1 that gradually expands in diameter downward from the lower end of the mouth portion 1a and a body main portion 1b2 that extends downward from the lower end of the shoulder portion 1b1. The body main portion 1b2 has a cylindrical shape in the present embodiment, but is not limited thereto.

[0021] As shown in Fig. 2, the discharge cap 2 has a co-rotating engagement portion 7 that engages with the inner container 5 in the circumferential direction on one side at the mouth portion 1a so as to be co-rotatable, and is attached to the inner container 5 by screwing. The inner container 5 has a screwing portion 5b1 that engages with the outer container 4 at the mouth portion 1a so as to be able to rise while rotating in the circumferential direction on one side. In this embodiment, the screwing portion 5b1 is formed by transferring the shape of the thread provided on the outer preform to the vertical rib provided on the inner preform by screwing the inner preform onto the outer preform at the mouth portion 1a. In this embodiment, the inner container 5 has an inner cylindrical portion 5a facing the inner circumferential surface of the outer container 4 at the mouth portion 1a, an outer cylindrical portion 5b facing the outer circumferential surface of the outer container 4 at the mouth portion 1a, and an upper wall portion 5c connecting the upper end portion of the inner cylindrical portion 5a to the upper end portion of the outer cylindrical portion 5b. The inner circumferential surface of the outer cylindrical portion 5b has the screwing portion 5b1. The co-rotating engagement portion 7 of the discharge cap 2 engages with the outer circumferential surface of the outer cylindrical portion 5b so as to be co-rotatable in the circumferential direction on one side. Note that the screwing portion 5b1 is not limited to the configuration formed by transfer.

[0022] The discharge cap 2 has a mounting cylinder 11a that is attached to the outer cylindrical portion 5b by screwing (an operation of pressing downward), and the co-rotating engagement portion 7 is provided on the inner circumferential surface of the mounting cylinder 11a. Further, the discharge cap 2 has a top wall 11b that is connected to the upper end portion of the mounting cylinder 11a and has a discharge port (not shown) for discharging the contents in the internal space S through the check valve 6, and an upper lid 11c that is rotatably connected to the upper end portion of the mounting cylinder 11a via a hinge portion 11d and can open and close the discharge port. The discharge cap 2 has a hinge cap 11 including the top wall 11b, the upper lid 11c, a middle plug 12 that is attached to the hinge cap 11 and is disposed between the lower surface of the top wall 11b and the upper surface of the mouth portion 1a, and a valve member 13 that integrally includes a check valve body 6a forming the check valve 6 and an outside air check valve body 8a forming the outside air check valve 8 and is sandwiched between the lower surface of the top wall 11b and the upper surface of the middle plug 12. The upper wall portion 5c of the inner container 5 has a vent hole 10 that communicates with an outside air inlet 1d provided in the outer container 4. The discharge cap 2 has a ventilation path 9 that sucks in outside air due to the decompression of the gap between the inner container 5 and the outer container 4 and guides the outside air to the vent hole 10 of the double container 1 through the outside air check valve 8. Note that the discharge cap 2 is not limited to the configuration including three components: the hinge cap 11, the valve member 13, and the middle plug 12.

[0023] The bottom 1c of the double container 1 has a central concave portion 1c1 that is recessed upward at the central portion when viewed from the bottom surface of the bottom 1c. The outer peripheral wall portion 14 of the central concave portion 1c1 is composed of a main body outer peripheral wall 14a formed by the outer container 4 and a sub-outer peripheral wall 14b formed by the inner container 5 and contacting the outer peripheral surface of the main body outer peripheral wall 14a. The top wall portion 15 of the central concave portion 1c1 is composed of a main body top wall 15a formed by the outer container 4 and a sub-top wall 15b formed by the inner container 5 and contacting the upper surface of the main body top wall 15a. The outer peripheral wall portion 14 has a screw-shaped portion 16 that has a shape along a thread 17a that spirally extends downward to the lower end of the outer peripheral wall portion 14. In the screw-shaped portion 16, irregularities are formed on the inner surface and the outer surface of the outer peripheral wall portion 14 according to the shape of the thread 17a. The thread 17a is illustrated as a single-thread in the present embodiment, but is not limited thereto, and may be a multi-thread having two or more threads. In the present embodiment, the bottom 1c has, in the radially outer side of the central concave portion 1c1, a grounding portion 1c2 located at the outer peripheral edge of the bottom 1c, and an annular concave portion 1c3 that is gradually recessed upward from the grounding portion 1c2 toward the central concave portion 1c1 and forms an annular shape when viewed from the bottom surface, but is not limited thereto.

[0024] As shown by the two-dot chain line in FIG. 1, the central concave portion 1c1 can be formed by using a blow molding die having a movable portion 17 (see FIG. 1) that can descend while rotating around the axis of the central concave portion 1c1 (coinciding with the central axis O in the present embodiment) with respect to the double container 1 after the formation of the double container 1. In this case, since the movable portion 17 has a thread 17a that extends downward to the lower end of the outer peripheral wall portion 14, it can be demolded without forced ejection (demolding while elastically deforming the double container 1). Therefore, the protruding height H of the uneven portion (bent to form a thread shape) for engaging the main body outer peripheral wall 14a and the sub-outer peripheral wall 14b with each other can be set high, and the engaging force between the main body outer peripheral wall 14a and the sub-outer peripheral wall 14b can be easily obtained. The movable portion 17 may be configured as a movable die portion for forming the bottom 1c of the double container 1 in the blow molding die, or may be configured as a movable rod that descends together with the bottom 1c while supporting the lower surface of the bottom 1c of the preform during the longitudinal stretching in order to stabilize the longitudinal stretching (stretching in the vertical direction) during the biaxial stretch blow molding.

[0025] According to the discharge container 3 having the screw-shaped portion 16 at the bottom 1c, when the inner container 5 peels off from the outer container 4 as the content is discharged, as shown in FIG. 3, the peeling of the inner container 5 from the outer container 4 at the bottom 1c can be suppressed by the engaging force between the main body outer peripheral wall 14a and the sub-outer peripheral wall 14b at the screw-shaped portion 16. Therefore, it is possible to prevent the inner container 5 from being excessively crushed so as to be constricted at the body portion 1b, and prevent the content remaining on the bottom 1c side from the constricted portion from being unable to be discharged.

[0026] Also, in the present embodiment, in the screw-shaped portion 16, the sub-outer peripheral wall 14b can be unscrewed from the main body outer peripheral wall 14a by rotating in one circumferential direction. That is, the rotation direction of the inner container 5 for unscrewing the sub-outer peripheral wall 14b from the main body outer peripheral wall 14a is the same as the rotation direction of the inner container 5 for unscrewing the screwed portion 5b1 of the inner container 5 from the outer container 4 at the mouth portion 1a. Therefore, at the time of separate disposal or the like, an operation of rotating the discharge cap 2 in one circumferential direction with respect to the outer container 4 is performed from the state as shown in FIG. 3 after the content is discharged, and the inner container 5 is rotated in one circumferential direction via the co-rotation engaging portion 7. When the inner container 5 is lifted with respect to the outer container 4 via the screwed portion 5b1 and taken out from the outer container 4, the sub-outer peripheral wall 14b can be easily separated from the main body outer peripheral wall 14a by unscrewing.

[0027] Also, in the present embodiment, the outer diameter D1 of the screw-shaped portion 16 is equal to or less than the inner diameter D2 of the outer container 4 at the mouth portion 1a. Therefore, when taking out the inner container 5 from the outer container 4, as shown in FIG. 4, it is possible to prevent the sub-outer peripheral wall 14b of the inner container 5 from being caught by the inner peripheral surface of the outer container 4 at the mouth portion 1a and becoming difficult to take out.

[0028] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and the above-described embodiments can be variously modified without departing from the gist of the present invention. For example, the rotational direction of the inner container 5 for screwing off the sub outer peripheral wall 14b from the main body outer peripheral wall 14a may be different from the rotational direction of the inner container 5 for screwing off the screwing portion 5b1 of the inner container 5 from the outer container 4 at the mouth portion 1a. The inner container 5 may be configured such that the screwing portion 5b1 is not provided, and when the inner container 5 is taken out of the outer container 4 at the time of separate disposal or the like, the inner container 5 is pulled out of the outer container 4 without rotating the inner container 5 with respect to the outer container 4. The discharge container 3 is not limited to a type (so-called, laminated peeling container or delamination container) in which the outer container 4 is restored and deformed while maintaining the reduced volume state of the inner container 5 as the content is discharged, thereby introducing outside air into the gap between the inner container 5 and the outer container 4. That is, the discharge container 3 may be configured such that the discharge cap 2 does not have a check valve 6 and the double container 1 does not have an outside air introduction port 1d.

Explanation of Signs

[0029] 1 Double container 1a Mouth portion 1b Body portion 1b1 Shoulder portion 1b2 Body main portion 1c Bottom portion 1c1 Central concave portion 1c2 Grounding portion 1c3 Annular concave portion 1d Outside air introduction port 2 Discharge cap 3 Discharge container 4 Outer container 5 Inner container 5a Inner cylindrical portion 5b Outer cylindrical portion 5b1 Screwing portion 5c Upper wall portion 6 Check valve 6a Check valve body 7 Co-rotation engagement portion 8 Outside air check valve 8a Outside air check valve body 9 Vent passage 10 Vent hole 11 Hinge cap 11a Mounting cylinder 11b Top wall 11c Upper lid 11d Hinge part 12 Inner plug 13 Valve member 14 Outer peripheral wall part 14a Main body outer peripheral wall 14b Sub-outer peripheral wall 15 Top wall part 15a Main body top wall 15b Sub-top wall 16 Threaded shape part 17 Movable part 17a Thread crest D1 Outer diameter D2 Inner diameter H Protrusion height O Central axis S Internal space

Claims

1. A double container having a mouth part, a body part, and a bottom part connected in this order, and composed of an outer container and an inner container, wherein the bottom part has a central concave part that is concave upward, the outer peripheral wall part of the central concave part is composed of a main body outer peripheral wall formed by the outer container and a sub-outer peripheral wall formed by the inner container and contacting the outer peripheral surface of the main body outer peripheral wall, the outer peripheral wall part has a screw-shaped part having a shape along a thread spirally extending downward to the lower end of the outer peripheral wall part, the double container.

2. The double container according to claim 1, wherein the outer diameter of the screw-shaped part is equal to or less than the inner diameter of the outer container at the mouth part.

3. The inner container has a screwing part that can be screwed to the outer container at the mouth part so as to be able to rise while rotating in one circumferential direction, in the screw-shaped part, the sub-outer peripheral wall can be screwed off from the main body outer peripheral wall by rotation in one circumferential direction, the double container according to claim 1.

4. The double container according to any one of claims 1 to 3, and a discharge cap having a check valve, attached to the mouth part, and capable of discharging the content accommodated in the internal space of the inner container through the check valve, when the double container discharges the content, the inner container peels off from the outer container at the body part, so that outside air can be introduced between the outer container and the inner container, the discharge cap has a co-rotating engagement part that can be co-rotated in one circumferential direction with the inner container at the mouth part, and is attached to the inner container by a stopper, the inner container has a screwing part that can be screwed to the outer container at the mouth part so as to be able to rise while rotating in one circumferential direction, the discharge container.

Images