Double container
The double-walled container with a central recess and locking mechanism stabilizes inner container separation from the outer container, addressing deformation issues and ensuring complete discharge.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- YOSHINO KOGYOSHO CO LTD
- Filing Date
- 2024-12-26
- Publication Date
- 2026-07-08
AI Technical Summary
Existing double containers face issues where the inner container may deform unexpectedly or become constricted, preventing complete discharge of contents, especially when separating from the outer container during use or disposal, leading to hindered discharge.
A double-walled container design featuring a central recess with a main and secondary peripheral wall structure, incorporating undercut portions and locking mechanisms to stabilize the inner container's separation from the outer container, ensuring controlled disassembly and preventing deformation.
The design effectively suppresses unexpected deformation of the inner container, ensuring complete discharge of contents by maintaining structural integrity during separation from the outer container.
Smart Images
Figure 2026114757000001_ABST
Abstract
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 Document 1).
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 such a double container, for example, when the contents stored in the internal 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 internal space but between the outer container and the inner container. Therefore, the contact between the contents in the internal 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 before the contents are used up, the inner container may be overly crushed so as to be constricted in the body part, or the bottom of the inner container may be lifted, etc., which may inhibit the discharge of the contents. 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, there is a possibility that the inner container may peel off unexpectedly and inhibit the discharge of the contents.
[0005] Therefore, the object of the present invention is to provide a double-walled container that can suppress the occurrence of unexpected deformation in the body that would hinder the discharge of the contents. [Means for solving the problem]
[0006] One embodiment of the present invention is as follows:
[0007] [1] A double-walled container having a mouth, body, and bottom connected in that order, consisting of an outer container and an inner container, The bottom portion has a central recess that is recessed upwards, The peripheral wall portion of the central recess is composed of a main peripheral wall formed by the outer container and a secondary peripheral wall formed by the inner container. The main body peripheral wall has undercut portions that extend continuously or intermittently in the circumferential direction, such that the inner and outer circumferential surfaces of the main body peripheral wall have an annular shape formed by recesses that are radially recessed inward. A double-walled container, wherein the sub-circumferential wall has a shape that extends circumferentially along the outer surface of the main body circumferential wall in the undercut portion, and has a locking portion that is locked by the undercut portion.
[0008] [2] The double container according to [1], wherein the undercut portion and the locking portion have a shape in which the inner and outer surfaces of the peripheral wall portion are recessed radially inward, and the recesses extend continuously in the circumferential direction to form an annular shape.
[0009] [3] The top wall portion of the central recess is composed of a main top wall formed by the outer container and a secondary top wall formed by the inner container and extending along the main top wall. The main body periphery wall has an upper periphery wall that connects the undercut portion and the main body top wall. The double-walled container according to [1] or [2], wherein the upper circumferential wall of the main body has a shape in which the inner and outer circumferential surfaces of the upper circumferential wall of the main body have curved protrusions that project radially outward, forming an annular shape that extends in the circumferential direction.
[0010] [4] The bottom portion has a contact portion extending circumferentially in an annular shape at its outer peripheral edge, The main body periphery wall has a lower periphery wall that extends circumferentially to form an annular shape, with the outer peripheral edge of the bottom connected to the undercut portion of the main body periphery wall. The double container according to any one of [1] to [3], wherein the undercut portion is located radially inward from the ground portion. [Effects of the Invention]
[0011] According to the present invention, it is possible to provide a double-walled container that can suppress the occurrence of unexpected deformation in the body that would hinder the discharge of the contents. [Brief explanation of the drawing]
[0012] [Figure 1] This is a partial cross-sectional side view showing a double-walled container according to one embodiment of the present invention. [Modes for carrying out the invention]
[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0014] As shown in Figure 1, in one embodiment of the present invention, the double-walled container 1 has a cylindrical mouth portion 1a, a body portion 1b connected to the lower end of the mouth portion 1a, and a bottom portion 1c connected to the lower end of the body portion 1b, connected in this order. The body portion 1b has a shoulder region 1b1 that widens in diameter from the lower end of the mouth portion 1a, and a body body region 1b2 that extends downward from the lower end of the shoulder region 1b1. The bottom portion 1c has a central recess 2 that is recessed upward. The central recess 2 is a top-cylindrical shape having a circumferential wall portion 2a centered on a central axis O, and a top wall portion 2b connected to the upper end of the circumferential wall portion 2a. The central axis O of the circumferential wall portion 2a passes through the center of the mouth portion 1a.
[0015] In this embodiment, the direction along the central axis O is called the vertical direction, the direction from the bottom 1c to the mouth 1a along the vertical direction is called the upward direction, the opposite direction is called the downward direction, the direction perpendicular to the central axis O is called the radial direction, and the direction around the central axis O is called the circumferential direction.
[0016] The double-walled container 1 consists of an outer container 3 and an inner container 4. The inner container 4 forms an internal space S for containing contents (not shown). The capacity of the double-walled container 1 is not particularly limited, but it can be used as a double-walled container 1 for contents of 100 ml to 700 ml, for example. The contents are not particularly limited and can be liquids, food, etc.
[0017] The bottom 1c of the double-walled container 1 has an outer peripheral edge 1c1 and a central recess 2. The outer peripheral edge 1c1 has a ground contact portion 1c2 located at the outermost periphery of the bottom 1c, and an annular bottom wall 1c3 extending upward from the ground contact portion toward the central recess 2. The ground contact portion 1c2 extends continuously in the circumferential direction to form an annular shape, but it may also be configured to extend intermittently by providing recesses at intervals in the circumferential direction. The peripheral wall portion 2a of the central recess 2 extends radially inward and upward from the inner peripheral edge of the annular bottom wall 1c3. The peripheral wall portion 2a may also extend parallel to the vertical direction. The peripheral wall portion 2a of the central recess 2 is composed of a main peripheral wall 3a formed by the outer container 3 and a sub-peripheral wall 4a formed by the inner container 4 and extending along the main peripheral wall 3a. The top wall portion 2b of the central recess 2 is composed of a planar main top wall 3b formed by the outer container 3 and a secondary top wall 4b formed by the inner container 4 and extending along the main top wall 3b. Note that the top wall portion 2b (main top wall 3b) is not limited to a planar shape, but may be curved (dome-shaped), for example, convex upward or downward. Here, "extending along" means that opposing surfaces become identical or substantially identical in shape when they are in close contact or proximity.
[0018] The double container 1 has an outside air inlet 5 at the mouth part 1a for introducing outside air between the outer container 3 and the inner container 4 by peeling the inner container 4 from the outer container 3 as the content is discharged. In this embodiment, the outside air inlet 5 is constituted by a through-hole penetrating the outer container 3 in the radial direction. However, for example, it may be constituted by a gap provided between the upper end of the outer container 3 and the upper end of the inner container 4 at the mouth part 1a. Further, in this embodiment, the outside air inlet 5 is provided at the mouth part 1a, but is not limited thereto. For example, it may be provided at the body part 1b or the bottom part 1c.
[0019] Note that in the present application, the "peeling" includes not only the case where the inner container 4 and the outer container 3 are separated from a pseudo-adhesive state with almost no adhesive force intervening, but also the case where the inner container 4 and the outer container 3 are separated from a contact state (proximity state) with no adhesive force intervening.
[0020] In this embodiment, the double container 1 is formed by a biaxial stretch blow molding method in which a double-structured preform assembly in which a bottomed cylindrical outer preform corresponding to the outer container 3 and a bottomed cylindrical inner preform corresponding to the inner container 4 are assembled is set in a blow molding die, and the portions corresponding to the body part 1b and the bottom part 1c are stretched in the axial direction (vertical direction) and the radial direction to form a shape along the cavity of the blow molding die.
[0021] The outer preform and the inner preform are each formed, for example, by injection molding a biaxially stretchable PET (polyethylene terephthalate) resin such as homopolymer PET, IPA (isophthalic acid) modified PET, or CHDM (cyclohexanedimethanol) modified PET. Note that the outer preform and the inner preform may be formed of a resin other than the PET resin. The materials of the outer preform and the inner preform may be different.
[0022] A discharge cap (not shown) with a check valve is attached to the mouth 1a of the double container 1. By tilting the double container 1 and squeezing the body 1b, the contents are discharged from the internal space S through the check valve as the body 1b is reduced in volume by elastic deformation. When the squeeze operation is released, the check valve prevents outside air from entering the internal space S, maintaining the reduced volume state of the inner container 4. Meanwhile, due to the restoring force of the outer container 3, outside air is introduced between the outer container 3 and the inner container 4 through the outside air inlet 5, causing the inner container 4 to separate from the outer container 3.
[0023] At this time, if the inner container 4 separates from the outer container 3 at the bottom 1c, the inner container 4 may be excessively crushed at the body 1b, or the bottom 1c of the inner container 4 may rise, which may hinder the discharge of the contents. For this reason, the double-walled container 1 of this embodiment has a structure that suppresses separation at the central recess 2.
[0024] Specifically, the main peripheral wall 3a has an undercut portion 3a1 in which the inner and outer peripheral surfaces of the main peripheral wall 3a have a shape in which recesses (in other words, protrusions that project radially inward) extend continuously in the circumferential direction to form an annular shape, and the sub-peripheral wall 4a has a locking portion 4a1 that extends in the circumferential direction along the outer peripheral surface of the main peripheral wall 3a in the undercut portion 3a1 and is locked by the undercut portion 3a1.
[0025] The undercut portion 3a1 and the locking portion 4a1 have a shape in which the inner and outer surfaces of the peripheral wall portion 2a are recessed radially inward, forming an annular shape that extends continuously in the circumferential direction. The undercut portion 3a1 has a shape in which the inner and outer surfaces of the main peripheral wall 3a are curved so as to be recessed radially inward. In this embodiment, the undercut portion 3a1 has a shape in which the inner and outer surfaces of the main peripheral wall 3a are curved so as to be recessed radially inward, but it is not limited to this, and for example, the inner and outer surfaces of the main peripheral wall 3a may be bent so as to be recessed radially inward.
[0026] The main body perimeter wall 3a has an upper perimeter wall 3a2 that connects the undercut portion 3a1 and the main body top wall 3b, and a lower perimeter wall 3a3 that extends continuously in the circumferential direction to form an annular shape, connecting the annular bottom wall 1c3 of the outer peripheral edge portion 1c1 of the bottom portion 1c to the undercut portion 3a1 of the main body perimeter wall 3a. The upper perimeter wall 3a2 has a shape in which the inner and outer circumferential surfaces of the upper perimeter wall 3a2 are curved so as to protrude radially outward, and these protrusions extend continuously in the circumferential direction to form an annular shape. The undercut portion 3a1 is located radially inward from the contact portion 1c2.
[0027] The lower peripheral wall 3a3 of the main body may have a configuration having multiple intermittent protrusions and indentations in the circumferential direction, for purposes such as ensuring rigidity in the central recess 2 and providing a pressure absorption function to suppress localized indentation deformation of the container when the temperature drops. In this case, the protrusions and indentations have a shape in which the inner and outer peripheral surfaces protrude inward or outward from the container.
[0028] The central recess 2 can be formed during biaxial stretch blow molding by using a movable bottom mold that forms the bottom 1c of the double container 1, and moving it downward after the bottom 1c has been formed to create a so-called forced removal from the central recess 2 downwards.
[0029] The body portion 1b of the double-walled container 1 may have a configuration that includes, although not shown in the figures, vertical ribs to facilitate the intake path of outside air from the outside air inlet 5 to the main body region 1b2 of the body portion 1b, circumferential ribs to ensure the rigidity of the body portion 1b, and pressure absorption panels to provide a pressure absorption function.
[0030] According to this embodiment, when the inner container 4 separates from the outer container 3 as the contents are discharged, the undercut portion 3a1 of the outer container 3 engages with the locking portion 4a1 of the inner container 4, thereby suppressing separation of the inner container 4 from the outer container 3 in the central recess 2. Therefore, it is possible to suppress unexpected deformation in the body portion 1b that would hinder the discharge of the contents. Furthermore, in this embodiment, since the undercut portion 3a1 and the locking portion 4a1 extend continuously in the circumferential direction, the locking portion 4a1 can be locked around the entire circumference by the undercut portion 3a1, thereby enhancing the effect of suppressing separation in the central recess 2.
[0031] In this embodiment, the central recess 2 has the main body top wall 3b and the main body upper circumferential wall 3a2 which has a shape that extends circumferentially so as to form an annular ring with a horizontally oriented U-shaped portion. Therefore, good moldability can be achieved when the central recess 2 is formed by forcibly removing the bottom molding die. Furthermore, in this embodiment, the undercut portion 3a1 is located radially inward from the contact portion 1c2, which further improves moldability.
[0032] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and the embodiments described above can be modified in various ways without departing from the spirit of the present invention.
[0033] For example, in the embodiment described above, the double-walled container 1 has an outside air inlet 5, and as the contents are discharged, the inner container 4 separates from the outer container 3 and outside air is introduced through the outside air inlet 5. However, it is not limited to this, for example, it may be a double-walled container 1 that does not have an outside air inlet 5 and is only capable of separating the inner container 4 from the outer container 3 when separating and disposing of waste.
[0034] Furthermore, in the embodiment described above, the double-walled container 1 is formed by biaxial stretch blow molding using a double-walled preform assembly. However, it is not limited to this, for example, the inner container 4 may be blow-molded inside the outer container 3 after the outer container 3 has been blow-molded, or the outer container 3 and inner container 4 may be formed separately and then assembled.
[0035] Furthermore, in the embodiment described above, both the undercut portion 3a1 and the locking portion 4a1 have a shape in which the recess extends continuously in the circumferential direction so as to form an annular shape. However, the embodiment is not limited to this, and for example, both the undercut portion 3a1 and the locking portion 4a1 may have a shape in which the recess extends intermittently in the circumferential direction so as to form an annular shape. Also, when the outer container 3 and the inner container 4 are formed separately and then assembled, one of the recesses of the undercut portion 3a1 and the locking portion 4a1 may have a shape in which it extends continuously in the circumferential direction so as to form an annular shape, while the other recess may have a shape in which it extends intermittently in the circumferential direction so as to form an annular shape.
Explanation of Symbols
[0036] 1 Double container 1a Mouth part 1b Barrel part 1b1 Shoulder region 1b2 Barrel body region 1c Bottom part 1c1 Outer peripheral edge part 1c2 Grounding part 1c3 Annular bottom wall 2 Central concave part 2a Peripheral wall part 2b Top wall part 3 Outer container 3a Body peripheral wall 3a1 Undercut part 3a2 Upper body peripheral wall 3a3 Lower body peripheral wall 3b Body top wall 4 Inner container 4a Sub-peripheral wall 4a1 Locked part 4b Sub-top wall 5 Outside air inlet O Central axis S Internal space
Claims
1. A double-walled container having a mouth, body, and bottom connected in that order, consisting of an outer container and an inner container, The bottom portion has a central recess that is recessed upwards, The peripheral wall portion of the central recess is composed of a main peripheral wall formed by the outer container and a secondary peripheral wall formed by the inner container. The main body peripheral wall has undercut portions that extend continuously or intermittently in the circumferential direction, such that the inner and outer circumferential surfaces of the main body peripheral wall have an annular shape formed by recesses that are radially recessed inward. A double-walled container, wherein the sub-circumferential wall has a shape that extends circumferentially along the outer surface of the main body circumferential wall in the undercut portion, and has a locking portion that is locked by the undercut portion.
2. The double-walled container according to claim 1, wherein the undercut portion and the locking portion have a shape in which the inner and outer surfaces of the peripheral wall portion are recessed radially inward, and the recesses extend continuously in the circumferential direction to form an annular shape.
3. The top wall portion of the central recess is composed of a main top wall formed by the outer container and a secondary top wall formed by the inner container and extending along the main top wall. The main body periphery wall has an upper periphery wall that connects the undercut portion and the main body top wall. The double-walled container according to claim 1 or 2, wherein the upper circumferential wall of the main body has a shape in which the inner and outer circumferential surfaces of the upper circumferential wall of the main body have curved protrusions that project radially outward, forming an annular shape that extends in the circumferential direction.
4. The bottom portion has a contact portion extending circumferentially in an annular shape at its outer peripheral edge, The main body periphery wall has a lower periphery wall that extends circumferentially to form an annular shape, with the outer peripheral edge of the bottom connected to the undercut portion of the main body periphery wall. The double-walled container according to claim 1 or 2, wherein the undercut portion is located radially inward from the ground portion.