Double container

Abstract

The objective is to provide a double-walled container that has a high-quality appearance while reducing manufacturing costs. [Solution] A double-walled container 1 comprising a synthetic resin outer container 10 having a cylindrical mouth portion 11 and a transparent or translucent cylindrical body portion 12, and a bottomed cylindrical inner container 20 detachably mounted inside the outer container 10, wherein the inner circumferential surface 12b of the body portion 12 is larger in diameter than the inner diameter of the mouth portion 11, and has a shape with a convex portion 12c that extends around the entire circumference of the body portion 12 and has a cross section perpendicular to the circumferential direction that is convex radially inward.

Description

Technical Field

[0001] The present invention relates to a refillable double container in which an inner container is detachably attached inside an outer container.

Background Art

[0002] For example, as a container for storing contents such as cream cosmetics, there is a synthetic resin outer container having a cylindrical mouth part and a cylindrical body part, and a bottomed cylindrical inner container detachably attached inside the outer container. After the contents are used up, the empty inner container is removed from the outer container, and a new inner container filled with the contents is attached to the outer container, so that the contents can be easily refilled. Many double containers configured in this way are used.

[0003] Conventionally, as such a double container, the outer container is formed by injection molding using a transparent or translucent synthetic resin material into a shape with a thicker wall thickness in the body part than in the mouth part, so that the outer container has a high-class appearance (for example, a glass-like appearance) (see, for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the above conventional double container, in order to form a thick wall thickness in the body part, it is necessary to form the outer container in multiple injection moldings, and also the amount of the synthetic resin material used for the outer container increases, so there is a problem that the manufacturing cost of the double container increases.

[0006] The present invention aims to solve these problems, and its objective is to provide a double-walled container that has a high-quality appearance while reducing manufacturing costs. [Means for solving the problem]

[0007] The double-walled container of the present invention comprises an outer container made of synthetic resin having a cylindrical mouth and a transparent or translucent cylindrical body, and a bottomed cylindrical inner container detachably mounted inside the outer container, characterized in that the inner circumferential surface of the body is larger in diameter than the inner diameter of the mouth, and has a shape with a convex portion that extends over the entire circumference of the body and has a cross section perpendicular to the circumferential direction that is convex radially inward.

[0008] In the double-walled container of the present invention, it is preferable that the shape of the inner circumferential surface of the body portion in the portion where the protrusion is provided, in a cross section perpendicular to the circumferential direction, is an arc shape that is convex toward the radially inward direction.

[0009] In the double-walled container of the present invention, it is preferable that the outer surface of the body portion is cylindrical or truncated cone-shaped.

[0010] In the double-walled container of the present invention, it is preferable that the protrusions are provided in a range of 70% or more in the vertical direction of the inner circumferential surface of the body portion.

[0011] In the double-walled container of the present invention, it is preferable that the wall thickness at the thinnest part of the body is 0.5 to 1.5 mm, and the wall thickness at the thickest part of the body is 2 to 3 times the wall thickness at the thinnest part. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a double-walled container that has a high-quality appearance while reducing manufacturing costs. [Brief explanation of the drawing]

[0013] [Figure 1]This is a front view cross-sectional view of a double container according to one embodiment of the present invention. [Figure 2] This is a front view of the outer container shown in Figure 1, with a portion of it cut out. [Modes for carrying out the invention]

[0014] The double-walled container of the present invention will be described in more detail below with reference to the drawings.

[0015] The double-walled container 1 shown in Figure 1, according to one embodiment of the present invention, is used for purposes such as containing cream-type cosmetics as its contents. The double-walled container 1 comprises an outer container 10 and an inner container 20.

[0016] In the claims and this specification, the vertical direction refers to the vertical direction when the double container 1 is in an upright position, as shown in Figures 1 and 2.

[0017] As shown in Figures 1 and 2, the outer container 10 comprises a mouth portion 11 and a body portion 12.

[0018] The opening 11 is cylindrical with axis O as its axis, and a male screw 11a and a flange portion 11b are integrally provided on its outer surface. In addition, a cylindrical mounting tube portion 11c with axis O as its axis is integrally provided on the upper end portion of the opening 11.

[0019] As shown in Figure 1, a cap 30 is attached to the opening 11. The cap 30 is cylindrical with a top and is detachably attached to the opening 11 by screw connection to the male thread 11a. By attaching and detaching the cap 30 to the opening 11, the opening of the outer container 10 or inner container 20 can be opened and closed.

[0020] The opening 11 is not limited to a cylindrical shape; it may also be rectangular, elliptical, or otherwise cylindrical. Furthermore, instead of a male thread 11a, the opening 11 may be configured to have a projection for attaching the cap 30 by undercutting (undercut engagement).

[0021] As shown in FIGS. 1 and 2, the body portion 12 is cylindrical with the axis O as the center, and is integrally connected to the mouth portion 11 through the shoulder portion 13. The outer peripheral surface 12a of the body portion 12 has a larger diameter than the outer diameter of the mouth portion 11. The outer peripheral surface 12a of the body portion 12 is preferably cylindrical or frustum-shaped. That is, the outer peripheral surface 12a of the body portion 12 is preferably a smooth surface without irregularities, where the shape of the cross-section perpendicular to the circumferential direction centered on the axis O is linear. In the present embodiment, the outer peripheral surface 12a of the body portion 12 is cylindrical. The inner peripheral surface 12b of the body portion 12 has a larger diameter than the inner diameter of the mouth portion 11. Note that the inner peripheral surface 12b of the body portion 12 also has a larger diameter than the inner diameter of the mouth portion 11 even at the thickest part of the convex portion 12c described later. Further, in the present embodiment, the wall thickness of the body portion 12 is thinner than the wall thickness of the mouth portion 11. A bottom portion 14 is integrally provided at the lower end of the body portion 12 facing away from the mouth portion 11. Thereby, the lower end of the body portion 12 is closed by the bottom portion 14.

[0022] The body portion 12 is not limited to being cylindrical as long as it is tubular, and may be square tubular, elliptical tubular, or the like. Further, the outer container 10 may be configured such that the bottom portion 14 is not provided and the lower end of the body portion 12 is open.

[0023] The body portion 12 is transparent or translucent. In the present embodiment, the outer container 10 is formed into the above shape by blow molding a preform formed by injection molding a transparent polyethylene terephthalate resin (PET resin), and the entire mouth portion 11, body portion 12, shoulder portion 13, and bottom portion 14 are transparent. Note that being transparent or translucent means having a visible light transmittance such that the inside of the outer container 10 can be visually recognized from the outside of the outer container 10.

[0024] As long as at least the body portion 12 of the outer container 10 is transparent or translucent, for example, the portions other than the body portion 12 may not be transparent or translucent, such as making the mouth portion 11 white by crystallization. Further, the outer container 10 is not limited to being made of polyethylene terephthalate resin, and may be made of other synthetic resins as long as at least the body portion 12 can be made transparent or translucent.

[0025] As shown in Figure 1, the inner container 20 is a bottomed cylindrical shape, and its interior is a storage space 21 for contents (not shown). More specifically, the inner container 20 is a bottomed cylindrical shape having a cylindrical peripheral wall 22 with a smaller diameter than the opening 11 and a bottom wall 23 that closes the lower end of the peripheral wall 22. The inner container 20 also has a mounting portion 24 integrally provided at the upper end of the peripheral wall 22, and the inner container 20 is detachably attached to the opening 11, i.e., the outer container 10, by fitting the mounting portion 24 into the mounting cylinder portion 11c. When the inner container 20 is attached to the outer container 10, the peripheral wall 22 is arranged coaxially with the opening 11 and faces the body portion 12 of the outer container 10 at a predetermined distance, and the bottom wall 23 faces the bottom portion 14 at a predetermined distance, so that the inner container 20 is attached to the inside of the outer container 10.

[0026] In this embodiment, the mounting portion 24 is configured to integrally include a sealing portion 24a that, when the cap 30 is mounted on the opening portion 11, abuts against a sealing material 31 mounted on the inner surface of the top wall of the cap 30 to seal the space between the inner container 20 and the cap 30. Furthermore, a rotation-preventing portion 40 may be provided between the mounting cylinder portion 11c and the mounting portion 24 to prevent the inner container 20 from rotating relative to the outer container 10. In this embodiment, the inner container 20 is an injection-molded product made of synthetic resin, but it may also be made of thin metal or the like.

[0027] As shown in Figure 1, the inner circumferential surface 12b of the body portion 12 of the outer container 10 has a shape that extends over the entire circumference of the body portion 12 (the entire circumference in the circumferential direction centered on the axis O) and has a convex portion 12c whose cross-section perpendicular to the circumferential direction is convex radially inward.

[0028] In this embodiment, the shape of the inner circumferential surface 12b of the body portion 12 in the portion where the protrusion 12c is provided is an arc shape that is convex radially inward. That is, the portion of the body portion 12 where the protrusion 12c is provided has a shape that protrudes radially inward from the upper and lower ends of that portion, with the thickness gradually increasing toward the intermediate portion between the upper and lower ends.

[0029] Furthermore, the shape of the cross-section perpendicular to the circumferential direction of the inner circumferential surface 12b of the body portion 12 in the portion where the protrusion 12c is provided is not limited to an arc shape that is convex radially inward, but may be any other shape, such as a parabola, as long as it is a curved shape that is convex radially inward.

[0030] As shown in Figure 2, it is preferable that the protrusions 12c are provided in an area of ​​70% or more of the entire vertical range A of the inner circumferential surface 12b of the body portion 12. In this embodiment, the protrusions 12c are provided in the entire vertical range (100% range) A of the inner circumferential surface 12b of the body portion 12.

[0031] Furthermore, it is preferable that the outer container 10 has a wall thickness t1 of 0.5 to 1.5 mm at the thinnest part of the body 12 (the upper end of range A), and a wall thickness t2 at the thickest part of the body 12 (the central part in the vertical direction of range A) is 2 to 3 times the wall thickness t1 at the thinnest part. In this embodiment, the wall thickness t1 at the thinnest part of the body 12 is 1.0 mm, and the wall thickness t2 at the thickest part of the body 12 is 2.5 mm, so the wall thickness t2 is 2.5 times the wall thickness t1.

[0032] Furthermore, it is preferable that the wall thickness t2 is 1.3 mm or more thicker than the wall thickness t1.

[0033] In the double-walled container 1 according to this embodiment having the above configuration, the contents contained in the inner container 20 can be removed and used by removing the cap 30 from the mouth 11 of the outer container 10. Furthermore, after the contents have been used up, the contents can be easily refilled into the double-walled container 1 by removing the empty inner container 20 from the outer container 10 and attaching a new inner container 20 filled with contents to the outer container 10.

[0034] Furthermore, in the double-walled container 1 according to this embodiment, the inner circumferential surface 12b of the body portion 12 of the outer container 10 is made larger in diameter than the inner diameter of the mouth portion 11. With this configuration, the wall thickness of the body portion 12 in the double-walled container 1 according to this embodiment is thinner compared to conventional containers. As a result, in the double-walled container 1 according to this embodiment, the outer container 10 can be easily formed by blow molding a preform formed by injection molding, without having to form it by multiple injection molding processes, thereby reducing manufacturing costs. In addition, in the double-walled container 1 according to this embodiment, the amount of synthetic resin material used to form the outer container 10 can be reduced, which also reduces manufacturing costs.

[0035] On the other hand, in the double-walled container 1 according to this embodiment, the body portion 12 is made transparent or semi-transparent, and the inner circumferential surface 12b of the body portion 12 has a shape that includes a convex portion 12c that extends around the entire circumference of the body portion 12 and has a cross section perpendicular to the circumferential direction that is convex radially inward. Therefore, when the body portion 12 of the outer container 10 is viewed from the outside, the convex portion 12c creates a lens-like effect that refracts the light passing through the body portion 12, making the body portion 12 appear to waver like thick glass, thus giving the outer container 10, i.e., the double-walled container 1, a glass-like, high-quality appearance.

[0036] Thus, in the double-walled container 1 according to this embodiment, the outer container 10 having a transparent or translucent body portion 12 has an inner circumferential surface 12b of the body portion 12 that is larger in diameter than the inner diameter of the mouth portion 11, and the inner circumferential surface 12b of the body portion 12 has a shape that includes a convex portion 12c that extends around the entire circumference of the body portion 12 and has a cross section perpendicular to the circumferential direction that is convex radially inward. As a result, the double-walled container 1 can have a high-quality appearance while its manufacturing cost can be reduced.

[0037] Furthermore, in the double-walled container 1 according to this embodiment, since the outer peripheral surface 12a of the body portion 12 is cylindrical, the lens-like effect created by the protrusion 12c provided on the inner peripheral surface 12b of the body portion 12 can be more easily seen from the outside, thereby further enhancing the sense of luxury in the appearance of the outer container 10, i.e., the double-walled container 1.

[0038] Furthermore, in the double-walled container 1 according to this embodiment, the shape of the inner circumferential surface 12b of the body portion 12 in the portion where the protrusion 12c is provided is an arc shape that is convex radially inward. This allows the protrusion 12c to more effectively produce a lens-like effect, thereby further enhancing the luxurious appearance of the outer container 10, i.e., the double-walled container 1.

[0039] Furthermore, in the double-walled container 1 according to this embodiment, the protrusions 12c are provided in an area of ​​70% or more of the entire vertical range A of the inner circumferential surface 12b of the body portion 12, thereby further enhancing the luxurious appearance of the outer container 10, i.e., the double-walled container 1.

[0040] Even if the area where the protrusion 12c is provided is set to less than 70% of the entire vertical range A of the inner circumferential surface 12b of the body portion 12, the double-walled container 1 can be made to have a high-quality appearance while reducing its manufacturing cost. However, a portion of the inner circumferential surface 12b of the body portion 12 will have a uniform thickness, increasing the proportion of the body portion 12 where the lens-like effect of the protrusion 12c does not occur, thus diminishing the high-quality appearance of the double-walled container 1.

[0041] Furthermore, in the double-walled container 1 according to this embodiment, the wall thickness t1 at the thinnest part of the body 12 is set to 0.5 to 1.5 mm, and the wall thickness t2 at the thickest part of the body 12 is set to 2 to 3 times the wall thickness t1 at the thinnest part. This further enhances the sense of luxury in the appearance of the outer container 10, i.e., the double-walled container 1.

[0042] Even if there is a portion of the body 12 with a wall thickness of less than 0.5 mm, it is possible to reduce the manufacturing cost while still giving the double-walled container 1 a high-quality appearance. However, since it will be difficult to obtain a glass-like appearance in that portion, the high-quality appearance of the double-walled container 1 will be diminished accordingly.

[0043] Furthermore, even if the wall thickness t1 at the thinnest part of the body 12 exceeds 1.5 mm, the double container 1 can be made to have a high-quality appearance while reducing its manufacturing cost. However, this would result in a thicker wall thickness of the protrusion 12c, increasing the amount of synthetic resin material used to form the outer container 10, which would increase manufacturing costs due to a longer molding cycle, and raise concerns about sink marks occurring on the protrusion 12c.

[0044] Furthermore, even if the wall thickness t2 at the thickest part of the body 12 is less than twice the wall thickness t1 at the thinnest part, the double-walled container 1 can be made to have a high-quality appearance while reducing its manufacturing cost. However, the lenticular effect of the convex portion 12c will weaken the sense of wavering, and as a result, the high-quality appearance of the double-walled container 1 will be diminished.

[0045] Furthermore, if the thickness t2 at the thickest part of the body 12 exceeds three times the thickness t1 at the thinnest part, there is a risk that shrinkage may occur in the convex part 12c during molding.

[0046] The present invention is not limited to the embodiments described above, and it goes without saying that various modifications are possible without departing from the spirit of the invention.

[0047] For example, in the above embodiment, the outer circumferential surface 12a of the body portion 12 is cylindrical or truncated cone-shaped, but it is not limited to these and may be other shapes.

[0048] Furthermore, in the above embodiment, the inner circumferential surface 12b of the body portion 12 is shaped to have only one protrusion 12c, but it is not limited to this, and may be shaped to have multiple protrusions 12c arranged in the vertical direction. In this case, the multiple protrusions 12c may be the same in shape or size (length in the vertical direction and height of projection inward in the radial direction), or they may be different from each other. In this case as well, it is preferable that the range in which the multiple protrusions 12c are provided is 70% or more of the vertical range of the inner circumferential surface 12b of the body portion 12. [Explanation of Symbols]

[0049] 1 double container 10 Outer container 11 Mouth 11a Male thread 11b Flange section 11c Mounting tube section 12 Torso 12a Outer surface 12b Inner surface 12c convex part 12d Thinnest part 12e thickest part 13 Shoulder-shaped part 14 Bottom 20 Inner container 21 Containment space 22 Peripheral wall 23 Bottom wall 24 Mounting part 30 caps 31. Sealant 40 Anti-rotation part O axis A Full range t1 Thick t2 thick

Claims

1. A double-walled container comprising a synthetic resin outer container having a cylindrical mouth and a transparent or translucent cylindrical body, and a bottomed cylindrical inner container detachably mounted inside the outer container, A double-walled container characterized in that the inner circumferential surface of the body portion has a larger diameter than the inner diameter of the mouth portion, and the body portion has a shape that includes a convex portion that extends around the entire circumference and has a cross section perpendicular to the circumferential direction that is convex radially inward.

2. The double-walled container according to claim 1, wherein the shape of the inner circumferential surface of the body portion in the portion where the protrusion is provided is an arc shape that is convex toward the radially inward direction.

3. The double-walled container according to claim 1 or 2, wherein the outer surface of the body is cylindrical or truncated cone-shaped.

4. The double-walled container according to claim 1 or 2, wherein the protrusions are provided in a range of 70% or more in the vertical direction of the inner circumferential surface of the body.

5. The double-walled container according to claim 1 or 2, wherein the thickness of the thinnest part of the body is 0.5 to 1.5 mm, and the thickness of the thickest part of the body is 2 to 3 times the thickness of the thinnest part.

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