Double container

Abstract

To provide a double container having a structure capable of easily crushing a shoulder part of an inner container.SOLUTION: One embodiment of a double container comprises: an inner container in which volume-reducing deformation occurs as a stored content reduces; and an outer container in which the inner container is internally provided. A mouth part (11), a shoulder part (12), a trunk part, and a bottom part are downwardly arranged along a bottle axis direction (Z) in this order from an upper side. An outside air introduction hole for introducing outside air thereinto is provided between the outer container and the inner container according to the reduction of the content. The trunk part of the outer container is formed so as to be elastically deformed. A shoulder part (12a) of the outer container is formed so as to be elastically deformed according to the elastic deformation of the trunk part of the outer container. An outer shape (12s) of the shoulder part of the outer container is a square shape having an odd number of corners (12c) on a cross-sectional face orthogonal to the bottle axis direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Conventionally, as shown in Patent Document 1, for example, a double container has been known, which includes an inner container that shrinks and deforms as the contents contained therein decrease, and an outer container in which the inner container is placed, and in which the mouth, shoulder, body, and bottom are arranged in this order from top to bottom along the axial direction of the bottle, and an outside air inlet hole is provided to introduce outside air between the outer container and the inner container as the contents decrease. Such a double container is formed by integrally blow-molding the outer preform and the inner preform, with the inner preform for forming the inner container fitted into the outer preform for forming the outer container. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-18892 Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional double-layered containers described above, when the body is pressed radially inward, the shoulder of the inner container is difficult to deform, and the inner container is not crushed at the shoulder, or the inner container is crushed irregularly, etc. Therefore, it is difficult for outside air to flow between the inner and outer containers at the shoulder, and there are cases where the contents remain in a large amount, making it difficult to pour out the contents.

[0005] To address this issue, it has been considered to reduce the wall thickness of the shoulder of the inner container in order to make the shoulder more easily deformable. However, in order to produce the inner preform for forming the inner container by injection molding, it is necessary to ensure a certain wall thickness, and there is a limit to how thin the shoulder of the inner container formed by blow molding this inner preform can be. Therefore, reducing the wall thickness of the shoulder of the inner container does not make it sufficiently easy to crush.

[0006] In view of the above circumstances, one aspect of the present invention aims to provide a double container having a structure that makes the shoulder portion of the inner container more easily crushable. [Means for solving the problem]

[0007] One aspect of the double container of the present invention comprises an inner container that undergoes volume reduction and deformation as the contents contained therein decrease, and an outer container in which the inner container is housed, with the mouth, shoulder, body, and bottom arranged in this order from top to bottom along the bottle axial direction, an outside air inlet hole for introducing outside air between the outer container and the inner container as the contents decrease, the body of the outer container being formed to be elastically deformable, and the shoulder of the outer container being formed to be elastically deformable in accordance with the elastic deformation of the body of the outer container, and the outer shape of the shoulder of the outer container is an angular shape with an odd number of corners in a cross section perpendicular to the bottle axial direction. The shoulder portion of the outer container and the body portion of the outer container are connected by a connecting portion, which extends straight downward from the lower end of the shoulder portion of the outer container along the bottle axial direction and connects to the upper end of the body portion of the outer container, and the outer peripheral surface of the connecting portion is smooth. .

[0008] According to one aspect of the double-walled container of the present invention, the shoulder of the outer container is formed to be elastically deformable in response to the elastic deformation of the body of the outer container. In a cross section perpendicular to the bottle axial direction, the outer and inner preforms have an angular outer shape with an odd number of corners. The double-walled container is formed by integrally blow-molding the outer and inner preforms, with the inner preform fitted into the outer preform. When forming the double-walled container in this manner, the angular outer shape of the shoulder of the outer container makes it easier for gaps to form between the outer and inner containers at the corners during blow-molding of the outer and inner containers. Therefore, when a user squeezes the body of the outer container, causing the elastically deformed body to return to its original shape, ambient air is more likely to flow between the outer and inner containers through the gap at the shoulder. This facilitates the separation of the inner container from the outer container at the shoulder, preventing the shoulder of the inner container from collapsing.

[0009] Furthermore, because the outer shape of the shoulder of the outer container is angular, the outer shape of the shoulder of the inner container in a cross section perpendicular to the bottle axis direction also follows the angular shape of the shoulder of the outer container. Therefore, when outside air flows between the outer container and the inner container and the inner container collapses, the corners of the shoulder of the inner container tend to deform in a mountain fold, moving away from the bottle axis in the radial direction, and the circumferential center of the side of the shoulder of the inner container tends to deform in a valley fold, moving toward the bottle axis in the radial direction. In this way, the shoulder of the inner container can be deformed in accordance with the angular shape, thereby preventing the inner container from collapsing irregularly at the shoulder.

[0010] Furthermore, because the shoulder of the outer container is elastically deformable in response to the elastic deformation of the body of the outer container, when a user or the like elastically deforms the body of the outer container by squeezing the body, the elastic deformation occurring in the body of the outer container is propagated to the shoulder of the outer container, and the shoulder of the outer container also elastically deforms. This makes it easier to peel the inner container from the outer container at the shoulder than if the shoulder of the outer container did not elastically deform in response to the elastic deformation of the body of the outer container. Therefore, it is easier for outside air to flow between the outer container and the inner container at the shoulder, making the shoulder of the inner container more easily crushed in a suitable manner.

[0011] As described above, by forming the outer shape of the shoulder of the inner container in a rectangular shape in a cross section perpendicular to the bottle axis direction and allowing the shoulder of the outer container to elastically deform in response to the elastic deformation of the body of the outer container, the shoulder of the inner container can be made more easily crushable than when the outer shape of the shoulder of the inner container is simply rectangular. This allows the inner container to be easily crushed and deformed to reduce its volume, preventing the contents from becoming difficult to pour out. In particular, since the inner container tends to be easily crushed from the body to the shoulder, when the remaining amount of contents in the inner container becomes low, the shoulder of the inner container can be easily crushed, making it easier to pour out the remaining contents. This prevents the contents from remaining in the inner container. Furthermore, since the shoulder of the inner container can be made easily crushable without thinning it, the shoulder of the inner container can be made easily crushable while ensuring a certain thickness of the inner preform used to form the inner container, making it easier to produce the inner preform by injection molding.

[0012] Furthermore, according to one embodiment of the double-walled container of the present invention, the shoulder has an odd number of corners in its outer shape. Therefore, the corners and sides of the outer shape are positioned radially around the bottle axis. This means that, regardless of the direction in which a user presses the body, the direction in which the corners and sides press the body tends to be the direction in which the bottle axis is sandwiched between them. Therefore, regardless of the direction in which the body is pressed, the feeling (squeezing sensation) experienced by the user when squeezing and deforming the body tends to be the same. Therefore, when a user pours out the contents, there is no need to select a direction that is easy to deform the body, improving user convenience.

[0013] As described above, according to one aspect of the double container of the present invention, a double container is obtained that has a structure that makes it easy to crush the shoulder portion of the inner container in a suitable manner, while making it easy to squeeze the body portion evenly. When the inner container is crushed, the corners of the shoulder of the inner container tend to bend in a mountain-like shape, moving away from the bottle axis in the radial direction, as described above, but not all corners necessarily bend in this way. For example, some corners of the shoulder of the inner container may bend in a direction that moves inward in the radial direction toward the bottle axis.

[0014] The outer shape of the shoulder portion of the outer container may be pentagonal in a cross section perpendicular to the bottle axial direction. This configuration allows for a larger difference between the radial distance between the corners and the bottle axis and the radial distance between the sides and the bottle axis, compared to, for example, a case where the outer shape of the shoulder of the outer container is angular with seven or more corners. This allows the corners of the shoulder of the inner container to more easily bend radially outward in a mountain-like fashion, and allows the circumferential center of the side of the shoulder of the inner container to more easily bend radially inward in a valley-like fashion, when the shoulder of the inner container is crushed. Therefore, compared to, for example, a case where the outer shape of the shoulder of the outer container is angular with seven or more corners, the shoulder of the inner container can be more easily crushed (regularly). Note that if the number of corners in the shoulder shape is seven or more, the outer shape approaches a circle as the number of corners increases, which may make the shoulder of the inner container less susceptible to crushing.

[0015] The shoulder portion of the outer container and the body portion of the outer container are connected by a connecting portion, which extends straight downward from the lower end of the shoulder portion of the outer container along the bottle axis direction and connects to the upper end of the body portion of the outer container, and the outer surface of the connecting portion may be smooth. With this configuration, deformation of the body of the outer container is more easily transmitted to the shoulder of the outer container than, for example, when a circumferentially extending groove is formed between the shoulder of the outer container and the body of the outer container. This makes it easier for the shoulder of the outer container to elastically deform in accordance with the elastic deformation of the body of the outer container. Therefore, it is easier to peel the inner container from the outer container at the shoulder. This makes it easier for outside air to flow between the outer container and the inner container at the shoulder, making it easier for the shoulder of the inner container to collapse.

[0016] The upper end of the shoulder of the outer container may be smoothly connected to the lower end of the mouth of the outer container. With this configuration, compared to when the upper end of the shoulder of the outer container and the lower end of the mouth of the outer container are connected via a top surface that extends radially and is perpendicular to the bottle axial direction, the lower end of the mouth of the outer container serves as a fulcrum for more favorable elastic deformation of the shoulder of the outer container. This makes it easier to peel the inner container from the outer container at the shoulder, and more favorable to crush the shoulder of the inner container.

[0017] In a cross section perpendicular to the bottle axis direction, the shape of the side portion connecting the corners of the outer shape of the shoulder portion of the outer container may be an arc shape that convex radially outward. For example, if the corners of the outer container shoulder are sharply pointed outward in the radial direction, the corners of the inner container shoulder are also sharply pointed outward in the radial direction. In this case, the inner container shoulder may be more likely to tear at the corners when crushed. Furthermore, the inner container shoulder may be pinched between the corners of the outer container, making it difficult to separate the inner container shoulder from the outer container shoulder. Furthermore, when a user grasps the shoulder with their hand, the sharp corners may come into contact with their hand, making the shoulder uncomfortable to grip.

[0018] To address these problems, the above configuration allows the shape of the sides connecting the corners of the outer container's shoulder in a cross section perpendicular to the bottle axis direction to be an arc that convex radially outward. This prevents the corners connecting the sides from becoming sharply pointed radially outward. This prevents the corners of the inner container's shoulder in a cross section perpendicular to the bottle axis direction from becoming sharply pointed, preventing the inner container's shoulder from breaking at the corners. This also prevents the inner container's shoulder from becoming difficult to separate from the outer container's shoulder. This also prevents the shoulder from becoming uncomfortable to grip. [Effects of the Invention]

[0019] According to one aspect of the present invention, in a double container, the shoulder portion of the inner container can be made easily crushable. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a diagram showing a double container according to one embodiment. [Figure 2] FIG. 2 is a top view of the double container of one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, a double container according to one embodiment of the present invention will be described with reference to the drawings. Note that the scope of the present invention is not limited to the following embodiment, and can be modified as desired within the scope of the technical concept of the present invention. As shown in Fig. 1, the double container 10 of this embodiment includes an inner container 10b that shrinks and deforms as the contents stored therein decrease, and an outer container 10a in which the inner container 10b is placed. The double container 10 is a so-called delaminated container. The outer surface of the inner container 10b is separably provided on the inner surface of the outer container 10a. In the illustrated example, the inner container 10b is highly flexible and is peelably laminated on the inner surface of the outer container 10a. A gap may be provided between the inner surface of the outer container 10a and the outer surface of the inner container 10b.

[0022] The double container 10 is formed by integrally blow-molding the outer preform for forming the inner container 10b into the outer preform for forming the outer container 10a. In other words, the double container 10 is a biaxially stretched blown container. The outer container 10a and the inner container 10b are made of synthetic resin materials. The outer container 10a and the inner container 10b may be made of the same material or different materials. Examples of synthetic resin materials that can be used to form the outer container 10a and the inner container 10b include PET (polyethylene terephthalate), PP (polypropylene), PE (polyethylene), nylon (polyamide), and EVOH (ethylene-vinyl alcohol copolymer).

[0023] The double container 10 has a mouth 11, a shoulder 12, a body 13, and a bottom 14. The mouth 11, shoulder 12, body 13, and bottom 14 are arranged coaxially with a common axis and are arranged in this order along the common axis. Hereinafter, this common axis will be referred to as the bottle axis O, and the direction in which the bottle axis O extends will be referred to as the bottle axis direction Z. The bottle axis direction Z is indicated by the Z axis in each drawing. The side of the mouth portion 11 along the bottle axis direction Z, i.e., the side toward which the arrow of the Z axis points, will be referred to as the "upper side" or "upward." The side of the bottom portion 14 along the bottle axis direction Z, i.e., the side opposite to the side toward which the arrow of the Z axis points, will be referred to as the "lower side" or "downward." Furthermore, when viewed from the bottle axis direction Z, the direction intersecting the bottle axis O will be referred to as the radial direction, and the direction circumferential around the bottle axis O will be referred to as the circumferential direction.

[0024] In the double container 10, the mouth 11, shoulder 12, body 13, and bottom 14 are arranged in this order from top to bottom along the bottle axial direction Z. In a cross section perpendicular to the bottle axial direction Z, the outer shape of the double container 10 is a circle arranged coaxially with the bottle axis O, except for the shoulder 12. The shape of the shoulder 12 will be described in detail later.

[0025] The mouth 11 of the double container 10 is formed by stacking the mouth 11a of the outer container 10a and the mouth 11b of the inner container 10b. The shoulder 12 of the double container 10 is formed by stacking the shoulder 12a of the outer container 10a and the shoulder of the inner container 10b. The body 13 of the double container 10 is formed by stacking the body 13a of the outer container 10a and the body of the inner container 10b. The bottom 14 of the double container 10 is formed by stacking the bottom of the outer container 10a and the bottom of the inner container 10b. In the following description, unless otherwise specified, it is assumed that both the outer container 10a and the inner container 10b have the same shape.

[0026] A flange 11c is formed at the upper end of the mouth 11b of the inner container 10b, protruding radially outward and extending continuously over the entire circumferential length. The flange 11c is placed on the upper opening edge of the mouth 11a of the outer container 10a. On the outer peripheral surface of the mouth portion 11a of the outer container 10a, there are formed, in this order from top to bottom, a male thread portion 16a onto which a cap (not shown) is screwed, a sealed protrusion portion 16b onto which the peripheral wall portion of the cap (not shown) is fitted.

[0027] The sealed projection 16b and neck ring 16c protrude radially outward from the mouth 11a of the outer container 10a and extend continuously over the entire circumferential length. An airtight seal is formed between the outer peripheral surface of the sealed projection 16b and the inner peripheral surface of the peripheral wall of the cap (not shown). The outer diameter of the neck ring 16c is larger than the outer diameter of the sealed projection 16b. The neck ring 16c is located below the peripheral wall of the cap (not shown). The cap (not shown) may be fitted to the mouth 11a of the outer container 10a by undercut fitting.

[0028] The mouth 11 of the double container 10 is provided with an outside air introduction hole 20 that introduces outside air between the outer container 10a and the inner container 10b as the contents decrease. In the illustrated example, the outside air introduction hole 20 is formed in the mouth 11a of the outer container 10a. The outside air introduction hole 20 is located at the radially outermost part of the sealed protrusion 16b, and is located above the sealing surface that extends continuously over the entire circumferential length. The position where the outside air introduction hole 20 is formed is not particularly limited, and may be, for example, between the upper opening edge of the mouth 11a of the outer container 10a and the lower surface of the flange portion 11c of the mouth 11b of the inner container 10b.

[0029] A lower end 11d of the mouth 11a of the outer container 10a, located below the neck ring 16c, extends straight in the axial direction Z of the bottle. The shoulder portion 12 is connected to the lower end of the mouth portion 11. In this embodiment, the upper end of the shoulder portion 12 is smoothly connected to the lower end of the mouth portion 11. In other words, the upper end of the shoulder portion 12a of the outer container 10a is smoothly connected to the lower end 11d of the mouth portion 11a of the outer container 10a. The shoulder portion 12a of the outer container 10a extends radially outward as it extends downward from the lower end 11d of the mouth portion 11a of the outer container 10a. In other words, the radial dimension of the shoulder portion 12a of the outer container 10a increases as it extends downward.

[0030] The body 13 is connected to the lower part of the shoulder 12 via a connecting portion 15, which will be described later. The body 13 extends radially inward from the connecting portion 15 toward the center of the body 13 in the bottle axis direction Z, and extends radially outward from the center of the body 13 in the bottle axis direction Z downward. In other words, the outer diameter of the body 13 decreases from the upper end of the body 13 toward the center of the body 13 in the bottle axis direction Z, and increases from the center of the body 13 in the bottle axis direction Z toward the lower end of the body 13. In a cross section along the bottle axis direction Z, the body 13 has a curved, constricted shape that convexly extends radially inward. The outer diameter of the upper end of the body 13a of the outer container 10a is the same as the radial dimension of the lower end of the shoulder 12a of the outer container 10a.

[0031] In this embodiment, a plurality of grooves 30 are formed on the outer peripheral surface of the body portion 13a of the outer container 10a, recessed radially inward and extending in the bottle axial direction Z. The plurality of grooves 30 are arranged adjacent to one another along the circumferential direction. Note that the plurality of grooves 30 may also be arranged at intervals from one another in the circumferential direction. Alternatively, the plurality of grooves 30 may not be formed. The bottom portion 14 is connected to the lower part of the body portion 13. The bottom portion 14 is formed in a cylindrical shape with a bottom.

[0032] The shoulder 12 and the body 13 are connected by a connecting portion 15. The connecting portion 15 connects the lower end of the shoulder 12 to the upper end of the body 13. The connecting portion 15 is formed by stacking the connecting portion 15a of the outer container 10a and the connecting portion of the inner container 10b. The connecting portion 15a of the outer container 10a connects the lower end of the shoulder 12a of the outer container 10a to the upper end of the body 13a of the outer container 10a. As a result, the shoulder 12a of the outer container 10a and the body 13a of the outer container 10a are connected by the connecting portion 15. In this embodiment, the connecting portion 15a extends straight downward from the lower end of the shoulder 12a of the outer container 10a along the bottle axis direction Z and connects to the upper end of the body 13a of the outer container 10a.

[0033] The outer peripheral surface of the connecting portion 15 is free from irregularities and grooves extending in the circumferential direction. The outer peripheral surface of the connecting portion 15 is smooth. The outer peripheral surface of the connecting portion 15 is the radially outer surface of the connecting portion 15a of the outer container 10a. In this embodiment, the outer peripheral surface of the connecting portion 15 extends straight along the bottle axial direction Z. In this specification, "a certain object is smooth" means that the certain object is free from irregularities, grooves, etc., and is smooth.

[0034] The body 13a of the outer container 10a is formed to be elastically deformable. Furthermore, the shoulder 12a of the outer container 10a, which is connected to the body 13a of the outer container 10a via a connecting portion 15 having a smooth outer peripheral surface and extending straight along the bottle axis direction Z, is formed to be elastically deformable in response to the elastic deformation of the body 13a of the outer container 10a. When a user or the like squeezes the body 13 to elastically deform the body 13a of the outer container 10a, the elastic deformation occurring in the body 13a of the outer container 10a propagates to the connecting portion 15a of the outer container 10a and the shoulder 12a of the outer container 10a, causing the connecting portion 15a of the outer container 10a and the shoulder 12a of the outer container 10a to elastically deform. Note that portions of the outer container 10a other than the shoulder 12a, the body 13a, and the connecting portion 15a may be elastically deformable.

[0035] When a user grasps and applies pressure to the body 13, squeezing and deforming the body 13, various portions of the outer container 10a elastically deform as described above, and the inner container 10b also shrinks and deforms. This causes the contents contained in the inner container 10b to be poured out through a spout formed in a cap (not shown). When the user releases the pressure on the body 13, the elastically deformed outer container 10a returns to its original shape. At this time, the inner container 10b separates from the outer container 10a, creating a space between the outer container 10a and the inner container 10b, creating a negative pressure in that space. This allows outside air to be introduced between the outer container 10a and the inner container 10b through the outside air inlet hole 20.

[0036] Next, the shape of the shoulder 12 will be described in detail. Because the shape of the shoulder 12a of the outer container 10a and the shape of the shoulder of the inner container 10b are the same, the shape of the shoulder 12a of the outer container 10a will be described below as a representative. In Figure 2, the outline of the shoulder 12a in cross section AA in Figure 1, which is a cross section perpendicular to the bottle axial direction Z, is shown by a two-dot chain line.

[0037] As shown in FIG. 2, in a cross section perpendicular to the bottle axial direction Z, the outer shape 12s of the shoulder 12a of the outer container 10a is angular, having an odd number of corners 12c. In this embodiment, in a cross section perpendicular to the bottle axial direction Z, the outer shape 12s of the shoulder 12a of the outer container 10a is pentagonal. That is, the outer shape 12s of the shoulder 12a has five corners 12c. The five corners 12c are arranged at equal intervals around the circumference. In this embodiment, the outer shape 12s of the shoulder 12a of the outer container 10a is a regular pentagon. In this embodiment, the corners 12c are rounded.

[0038] The outer shape 12s of the shoulder 12a has five sides 12d. Each side 12d connects adjacent corners 12c in the circumferential direction. The outer shape 12s of the shoulder 12a has a shape in which the five sides 12d are connected in the circumferential direction via each corner 12c. Each side 12d is located radially inward of each corner 12c. In the outer shape 12s of the shoulder 12a, each corner 12c is located at the outermost position in the radial direction. In other words, each corner 12c is located at the position of the outer shape 12s farthest radially from the bottle axis O.

[0039] The side portions 12d have the same shape except for their different circumferential positions. In this embodiment, in a cross section perpendicular to the bottle axis direction Z, the shape of the side portions 12d connecting the corner portions 12c of the outer shape 12s of the shoulder portion 12a of the outer container 10a is an arc shape that convex radially outward. The radius of curvature of each side portion 12d is greater than the radial distance between the bottle axis O and the corner portion 12c. In this embodiment, each side portion 12d is formed into an arc shape by connecting portions having different radii of curvature. Note that each side portion 12d may also be an arc shape with a single radius of curvature. In the outer shape 12s at the center of the shoulder portion 12a in the bottle axis direction Z, the radius of curvature of a portion including the circumferential center of each side portion 12d is, for example, 23.0 mm or more and 25.0 mm or less. Note that the radius of curvature of each side portion 12d is not particularly limited. The circumferential center of each side 12d is located at the radially innermost position of the side 12d. The circumferential center of the side 12d is located at the position radially closest to the bottle axis O of the outer shape 12s.

[0040] In this specification, "a certain outer shape is angular" means that a certain outer shape is a closed linear shape formed by connecting multiple sides with corners. "Angular corners" are only required to be parts where sides are connected and convex outward, and may be rounded corners or sharp corners. "Angular side parts" are parts of an angular shape that are located between the corners, and may extend in a straight line or a curved line.

[0041] As shown in Fig. 1, the shoulder 12a of the outer container 10a is positioned radially outward as it extends downward, and therefore the outer shape 12s of the shoulder 12a in a cross section perpendicular to the bottle axial direction Z increases in radial dimension as it extends downward. In this embodiment, the shoulder 12a of the outer container 10a is generally pentagonal truncated pyramid-shaped, with the outer shape 12s increasing in radial dimension as it extends downward. In the shoulder 12a, the ridge 12e connecting the corners 12c of each outer shape 12s that extends in the bottle axial direction Z is curved in a cross section along the bottle axial direction Z, and is gently curved in a direction that bulges outward in the radial direction.

[0042] The outer peripheral surface of the shoulder portion 12a of the outer container 10a is composed of five curved surfaces 12f connected in the circumferential direction via ridge lines 12e. The curved surfaces 12f are parts that make up the side portions 12d of the outer shape 12s. In a cross section perpendicular to the bottle axial direction Z, the curved surfaces 12f have an arc shape that convex outward in the radial direction. In a cross section along the bottle axial direction Z, the curved surfaces 12f are curved in a direction that extends radially outward from top to bottom, and are gently curved in a direction that bulges outward in the radial direction.

[0043] According to this embodiment, the shoulder 12a of the outer container 10a is formed to be elastically deformable in response to the elastic deformation of the body 13a of the outer container 10a, and in a cross section perpendicular to the bottle axis direction Z, the outer shape 12s of the shoulder 12a of the outer container 10a is angular, having an odd number of corners 12c. As described above, the double container 10 is formed by integrally blow molding the outer preform for forming the outer container 10a and the inner preform, with the inner preform for forming the inner container 10b fitted into the outer preform for forming the outer container 10a. When forming the double container 10 in this manner, the angular shape 12s of the shoulder 12a makes it easier for gaps to form between the outer container 10a and the inner container 10b at the corners 12c when the outer container 10a and the inner container 10b are blow molded. Therefore, when a user or the like squeezes the body 13 to cause the elastically deformed body 13a of the outer container 10a to return to its original shape, outside air is likely to flow between the outer container 10a and the inner container 10b through the gap in the shoulder 12. This makes it easier to separate the inner container 10b from the outer container 10a at the shoulder 12, and prevents the shoulder 12 of the inner container 10b from being crushed.

[0044] Furthermore, because the outer shape 12s of the shoulder 12a of the outer container 10a is angular, the outer shape of the shoulder of the inner container 10b in a cross section perpendicular to the bottle axis direction Z also has an angular shape that conforms to the outer shape 12s of the shoulder 12a of the outer container 10a. Therefore, when outside air flows between the outer container 10a and the inner container 10b and the inner container 10b collapses, the corners of the shoulder of the inner container 10b tend to deform in a mountain fold in a direction away from the bottle axis O in the radial direction, and the circumferential center of the side of the shoulder of the inner container 10b tends to deform in a valley fold in a direction approaching the bottle axis O in the radial direction. In this way, the shoulder of the inner container 10b can be deformed in accordance with the angular shape, thereby preventing the inner container 10b from collapsing irregularly at the shoulder 12.

[0045] Furthermore, because the shoulder 12a of the outer container 10a is elastically deformable in response to the elastic deformation of the body 13a of the outer container 10a, when a user or the like elastically deforms the body 13a of the outer container 10a by squeezing the body 13, the elastic deformation occurring in the body 13a of the outer container 10a is propagated to the shoulder 12a of the outer container 10a, causing the shoulder 12a of the outer container 10a to also elastically deform. This makes it easier to separate the inner container 10b from the outer container 10a at the shoulder 12 than if the shoulder 12a of the outer container 10a did not elastically deform in response to the elastic deformation of the body 13a of the outer container 10a. This therefore makes it easier for outside air to flow between the outer container 10a and the inner container 10b at the shoulder 12, making the shoulder of the inner container 10b more easily crushable.

[0046] As described above, by forming the shoulder portion of the inner container 10b into a rectangular shape in a cross section perpendicular to the bottle axis direction Z and allowing the shoulder portion 12a of the outer container 10a to elastically deform in response to the elastic deformation of the body portion 13a of the outer container 10a, the shoulder portion of the inner container 10b can be more easily crushed than when the shoulder portion of the inner container 10b is simply rectangular. This allows the inner container 10b to be easily crushed and deformed to reduce its volume, preventing the contents from becoming difficult to pour out. In particular, because the inner container 10b is easily crushed from the body portion to the shoulder portion, when the remaining amount of contents in the inner container 10b becomes low, the shoulder portion of the inner container 10b can be easily crushed, making it easier to pour out the contents remaining in the inner container 10b. This prevents the contents from remaining in the inner container 10b. Furthermore, since the shoulder portion of the inner container 10b can be made easily crushable without being made extremely thin, the thickness of the inner preform for forming the inner container 10b can be secured to a certain extent, making it easier to suitably produce the inner preform by injection molding, while also making the shoulder portion of the inner container easily crushable.

[0047] Here, we consider the case where the number of corners 12c in the outer shape 12s of the shoulder 12a is an even number. In this case, the corners 12c are arranged at positions on either side of the bottle axis O in the radial direction, and the sides 12d are arranged at positions on either side of the bottle axis O in the radial direction. Therefore, for example, when the body 13 is pressed in a direction where the two corners 12c are sandwiched between the bottle axis O and when the body 13 is pressed in a direction where the two sides 12d are sandwiched between the bottle axis O, the ease of deformation (rigidity) of the body 13 differs, and the reaction force that a user or the like who presses the body 13 receives from the body 13 differs. That is, for example, when the two corners 12c of the shoulder 12a press the body 13 in the direction sandwiching the bottle axis O, the body 13 may be relatively difficult to deform, and the reaction force that the user receives from the body 13 may be relatively large. On the other hand, when the two sides 12d of the shoulder 12a press the body 13 in the direction sandwiching the bottle axis O, the body 13 may be relatively easy to deform, and the reaction force that the user receives from the body 13 may be relatively small. Therefore, depending on the direction in which the body 13 is pressed, the feeling that the user receives in their hand when squeezing and deforming the body 13 will differ. This results in a problem of reduced convenience for the user, such as the need to select a direction that makes it easy to deform the body 13 when pouring the contents.

[0048] In contrast, according to this embodiment, the number of corners 12c in the outer shape 12s of the shoulder portion 12a is an odd number. Therefore, the corners 12c and the sides 12d are the portions of the outer shape 12s that are arranged radially across the bottle axis O. As a result, regardless of the direction in which a user presses the body 13, the direction in which the corners 12c and the sides 12d press the body 13 tends to be the direction in which the bottle axis O is sandwiched between them. Therefore, regardless of the direction in which the body 13 is pressed, the feeling (squeezing sensation) that a user receives in their hand when squeezing and deforming the body 13 tends to be the same. Therefore, when a user pours out the contents, there is no need to select a direction that is easy to deform the body 13, which improves convenience for the user.

[0049] As described above, according to this embodiment, a double container 10 is obtained that has a structure that makes it easy to crush the shoulder portion of the inner container 10b and makes it easy to squeeze the body portion 13 evenly. When the inner container 10b is crushed, each corner of the shoulder of the inner container 10b is likely to bend in a mountain-like shape, moving away from the bottle axis O in the radial direction, as described above, but not all corners necessarily bend in a mountain-like shape. For example, some corners of the shoulder of the inner container 10b may bend in a direction that moves inward in the radial direction toward the bottle axis O.

[0050] Furthermore, according to this embodiment, the outer shape 12s of the shoulder 12a of the outer container 10a is pentagonal in a cross section perpendicular to the bottle axis direction Z. Therefore, compared to, for example, a case where the outer shape 12s of the shoulder 12a of the outer container 10a is a polygonal shape with seven or more corners, the difference in the radial direction between the corner 12c and the bottle axis O and the radial direction between the side 12d and the bottle axis O can be made larger. This makes it easier for the corners of the shoulder of the inner container 10b to bend radially outward in a mountain-like manner when the shoulder of the inner container 10b is crushed, and makes it easier for the circumferential center of the side of the shoulder of the inner container 10b to bend radially inward in a valley-like manner when the shoulder of the inner container 10b is crushed. Therefore, compared to, for example, a case where the outer shape 12s of the shoulder 12a of the outer container 10a is a polygonal shape with seven or more corners, the shoulder of the inner container 10b can be crushed more efficiently (regularly). If the number of corners 12c in the outer shape 12s of the shoulder 12a is seven or more, the outer shape 12s becomes closer to a circle as the number of corners 12c increases, which may make it more difficult for the shoulder of the inner container 10b to collapse.

[0051] Furthermore, according to this embodiment, the shoulder 12a of the outer container 10a and the body 13a of the outer container 10a are connected by a connecting portion 15a. The connecting portion 15a extends straight downward from the lower end of the shoulder 12a of the outer container 10a along the bottle axis direction Z and connects to the upper end of the body 13a of the outer container 10a. The outer peripheral surface of the connecting portion 15a is smooth. Therefore, deformation of the body 13a of the outer container 10a is more easily transmitted to the shoulder 12a of the outer container 10a than, for example, when a circumferentially extending groove is formed between the shoulder 12a of the outer container 10a and the body 13a of the outer container 10a. This allows the shoulder 12a of the outer container 10a to more easily elastically deform in accordance with the elastic deformation of the body 13a of the outer container 10a. This allows the inner container 10b to be more easily separated from the outer container 10a at the shoulder 12. Therefore, it is possible to more easily and suitably allow outside air to flow between the outer container 10a and the inner container 10b at the shoulder portion 12, and it is possible to more easily and suitably collapse the shoulder portion of the inner container 10b.

[0052] In particular, as in this embodiment, the shape of the body 13 is made to be a curved, constricted shape that convex radially inward, and no circumferentially extending grooves are provided in the upper part of the body 13a of the outer container 10a and in the connection part 15a of the outer container 10a, but rather a smooth connection is made from the constricted part of the body 13a to the shoulder part 12a of the outer container 10a.This makes it easier to more effectively propagate the elastic deformation that occurs in the body 13a of the outer container 10a to the shoulder part 12a when the body 13 is squeeze-deformed.

[0053] Furthermore, according to this embodiment, the upper end of the shoulder 12a of the outer container 10a is smoothly connected to the lower end of the mouth 11a of the outer container 10a. Therefore, compared to when the upper end of the shoulder 12a of the outer container 10a and the lower end of the mouth 11a of the outer container 10a are connected via a top surface that extends radially and is perpendicular to the bottle axis direction Z, the shoulder 12a of the outer container 10a can be more easily elastically deformed with the lower end of the mouth 11a of the outer container 10a as a fulcrum. This makes it easier to separate the inner container 10b from the outer container 10a at the shoulder 12a, and to crush the shoulder of the inner container 10b more easily.

[0054] For example, if the corners 12c of the outer shape 12s of the shoulder 12a of the outer container 10a are sharpened radially outward, the corners of the outer shape of the shoulder of the inner container 10b will also be sharpened radially outward. In this case, when the shoulder of the inner container 10b is crushed, the shoulder of the inner container 10b may be easily torn at the corners. Furthermore, the corners of the inner container 10b may be pinched inside the corners 12c of the outer container 10a, making it difficult for the shoulder of the inner container 10b to separate from the shoulder 12a of the outer container 10a. Furthermore, when a user grasps the shoulder 12a with their hand, the sharp corners 12c may come into contact with the hand, making the shoulder 12a uncomfortable to grip.

[0055] To address these problems, according to this embodiment, in a cross section perpendicular to the bottle axis direction Z, the shape of the side 12d connecting the corners 12c of the outer shape 12s of the shoulder 12a of the outer container 10a is an arc shape that convex radially outward. This prevents the corners 12c connecting the side 12d from becoming sharper radially outward. This prevents the corners of the outer shape of the shoulder of the inner container 10b from becoming sharper in a cross section perpendicular to the bottle axis direction Z, thereby preventing the shoulder of the inner container 10b from breaking at the corners. This also prevents the shoulder of the inner container 10b from becoming difficult to separate from the shoulder 12a of the outer container 10a. This also prevents the shoulder 12a from becoming uncomfortable to grip.

[0056] The present invention is not limited to the above-described embodiment, and the following configurations and methods may also be adopted. In a cross section perpendicular to the bottle axial direction, the outer shape of the shoulder of the outer container may be any angular shape having an odd number of corners. In a cross section perpendicular to the bottle axial direction, the outer shape of the shoulder of the outer container may be an angular shape having three corners, an angular shape having seven corners, or an odd number of corners (9 or more). The odd number of corners do not have to be equally spaced along the circumferential direction. In a cross section perpendicular to the bottle axial direction, the corners of the outer shape of the shoulder of the outer container may be sharp. In a cross section perpendicular to the bottle axial direction, the shape of the sides connecting the corners of the outer shape of the shoulder of the outer container may be straight.

[0057] The outer peripheral surface of the shoulder of the outer container may be formed with grooves extending in the axial direction of the bottle, similar to the body 13a of the above-described embodiment. In this case, in a cross section perpendicular to the axial direction of the bottle, the shape of the sides connecting the corners of the outer container shoulder may be curved or linear, with the grooves forming irregularities. A groove extending in the circumferential direction may be formed on the outer peripheral surface of the connecting portion connecting the shoulder portion of the outer container and the body portion of the outer container. The connecting portion may have a shape whose radial dimension changes along the bottle axial direction. In a cross section along the bottle axial direction, the outer peripheral surface of the connecting portion may be curved. Even in this case, if the outer peripheral surface of the connecting portion is smooth, elastic deformation of the body portion of the outer container can be easily propagated to the shoulder of the outer container via the connecting portion. The outer peripheral surface of the connecting portion may be formed with a groove or a ridge extending in the bottle axial direction. Even in this case, if no groove extending in the circumferential direction is formed on the outer peripheral surface of the connecting portion, elastic deformation of the body portion of the outer container can be easily propagated to the shoulder of the outer container via the connecting portion. The shoulder portion of the outer container and the body portion of the outer container may be directly connected to each other without providing the connecting portion. The configurations described in this specification can be combined with each other within the scope of not being mutually contradictory.

[0058] The aspects of the present invention are as follows, for example. <1> The bottle comprises an inner container that shrinks and deforms as the contents stored therein decrease, and an outer container in which the inner container is housed, and the bottle has a mouth, a shoulder, a body, and a bottom, which are arranged in this order from top to bottom along the bottle axis; an air inlet hole is provided between the outer container and the inner container to introduce outside air as the contents decrease; The body of the outer container is formed to be elastically deformable, the shoulder portion of the outer container is formed to be elastically deformable in accordance with the elastic deformation of the body portion of the outer container, A double container, wherein in a cross section perpendicular to the bottle axial direction, the outer shape of the shoulder portion of the outer container is an angular shape having an odd number of corners. <2> In a cross section perpendicular to the bottle axial direction, the outer shape of the shoulder portion of the outer container is pentagonal. <1> The double container described in . <3> the shoulder portion of the outer container and the body portion of the outer container are connected by a connecting portion, the connecting portion extends straight downward along the bottle axis direction from the lower end of the shoulder portion of the outer container to connect to the upper end of the body portion of the outer container, The outer peripheral surface of the connection portion is smooth. <1> or <2> The double container described in . <4> The upper end of the shoulder portion of the outer container is smoothly connected to the lower end of the mouth portion of the outer container. <3> The double container described in . <5> In a cross section perpendicular to the bottle axial direction, the shape of the side portion connecting the corner portions of the outer shape of the shoulder portion of the outer container is an arc shape that is convex outward in the radial direction. <1> from <4> 1. A double container according to any one of the preceding items. [Explanation of symbols]

[0059] 10...double container, 10a...outer container, 10b...inner container, 11, 11a, 11b...mouth, 12, 12a...shoulder, 12c...corner, 12d...side, 12s...outer shape, 13, 13a...body, 14...bottom, 15, 15a...connection, 20...external air inlet, O...bottle axis, Z...bottle axis direction

Claims

1. The bottle comprises an inner container that shrinks and deforms as the contents stored therein decrease, and an outer container in which the inner container is housed, and the bottle has a mouth, a shoulder, a body, and a bottom, which are arranged in this order from top to bottom along the bottle axis; an air inlet hole is provided between the outer container and the inner container to introduce outside air as the contents decrease; The body of the outer container is formed to be elastically deformable, the shoulder portion of the outer container is formed to be elastically deformable in accordance with the elastic deformation of the body portion of the outer container; In a cross section perpendicular to the bottle axial direction, the outer shape of the shoulder of the outer container is an angular shape having an odd number of corners, the shoulder portion of the outer container and the body portion of the outer container are connected by a connecting portion, the connecting portion extends straight downward along the bottle axis direction from the lower end of the shoulder portion of the outer container to connect to the upper end of the body portion of the outer container, The outer circumferential surface of the connecting portion is smooth.

2. 2. The double container according to claim 1, wherein the outer shape of the shoulder portion of the outer container is pentagonal in a cross section perpendicular to the bottle axial direction.

3. 3. The double container according to claim 1, wherein an upper end of the shoulder portion of the outer container is smoothly connected to a lower end of the mouth portion of the outer container.

4. 3. The double container according to claim 1, wherein in a cross section perpendicular to the bottle axis direction, the shape of the edge portion connecting the corners of the outer container shoulder is an arc shape that convex radially outward.

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