Double container

Abstract

To provide a double container capable of easily detaching and separating an inner layer body from an outer layer body.SOLUTION: A double container comprises: an outer layer body 10 having an opening 11, a shoulder portion 12, a barrel portion 13, and a bottom portion 15 connected via a heel portion 14; and an inner layer body 20 having a mouth-neck portion 21 and a wall portion 22 detachably layered on an inner wall surface of the outer layer body 10 over an area extending from a tip of the opening 11 of the outer layer body 10 to the bottom portion 15. The double container allows the inner layer body 20 to be pulled out from the outer layer body 10 by lifting the mouth-neck portion 21 after disengaging the connection between the mouth-neck portion 21 and the opening 11. Between the inner wall surface of the outer layer body 10 and the wall portion 22 of the inner layer body 20 layered on the inner wall surface, an air layer 3 formed by a fine uneven region and serving as a starting point for detaching the inner layer body 20 from the outer layer body 10 is provided.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a double container comprising an inner layer body for accommodating contents and an outer layer body for housing and holding the inner layer body. [Background technology]

[0002] In recent years, there has been a growing demand for recycling and reusing containers in order to reduce the burden on the environment. However, containers containing oily contents or contents other than food have been difficult to recycle because the dirt and odors that adhere to the containers cannot be removed.

[0003] For this reason, a double-layered container is known that is composed of an inner layer with which the contents come into direct contact and an outer layer that is peelably laminated to the outside of the inner layer, as in Patent Document 1. With this double-layered container, the thin-walled inner layer with the contents attached thereto can be separated from the outer layer, and the inner layer can be discarded, while the outer layer can be recycled or reused as is. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-151324 Summary of the Invention [Problem to be solved by the invention]

[0005] The above-mentioned double container can be manufactured by biaxially stretching blow molding a double preform made by combining an inner layer preform and an outer layer preform. However, the thickness of the inner layer body formed by the inner layer preform (0.05 to 0.1 mm) is significantly thinner than the thickness of the outer layer body formed by the outer layer preform (0.3 to 0.5 mm), and because of its good formability, the inner layer body adheres to the outer layer body, making it difficult to separate them after use, which was a problem.

[0006] Therefore, the present invention aims to solve these problems, and its object is to provide a double-layered container in which the inner layer can be easily peeled from the outer layer and separated. [Means for solving the problem]

[0007] The double container of the present invention comprises an outer layer body having an opening having an open end that opens upward, a shoulder portion connected to the lower end of the opening, a body portion connected to the lower end of the shoulder, and a bottom portion connected to the lower end of the body portion via a heel portion; an inner layer body having an opening for pouring out the contents, the inner layer body having a neck portion exposed from the opening and detachably connected to the opening of the outer layer body, and a wall portion connected to the lower end of the neck portion and peelably laminated on the inner wall surface of the outer layer body over a region from the end of the opening of the outer layer body to the bottom, the inner side surrounded by the wall portion being a filling space for the contents; A double container in which the connection between the neck portion and the opening is released, and then the inner layer body can be removed from the outer layer body by lifting up the neck portion, The present invention is characterized in that an air layer is provided between the inner wall surface of the outer layer body and the wall portion of the inner layer body laminated on the inner wall surface, which is formed by a fine uneven area and serves as a starting point when the inner layer body is peeled off from the outer layer body.

[0008] In addition, in the double container of the present invention, it is preferable that the air layer is provided between the inner wall surface from the lower end of the opening of the outer layer to the boundary position where it transitions to the body portion and the wall portion of the inner layer body that is stacked on the inner wall surface.

[0009] In the double container of the present invention, it is preferable that the uneven area is formed by providing a rough surface portion on either or both of the inner wall surface of the outer layer body and the wall portion of the inner layer body.

[0010] In addition, in the double container of the present invention, it is preferable that the rough surface portion is formed by roughening either one or both of the inner layer preform and the outer layer preform of a double preform consisting of an inner layer preform and an outer layer preform used when molding a double container using a biaxially stretched blow molding method.

[0011] In the double container of the present invention, the surface roughness of the rough surface portion is preferably 1.2 μm or more and less than 2.2 μm. Note that the surface roughness (linear roughness) in the present invention means the arithmetic mean roughness Ra according to JIS B 0601-2001.

[0012] Furthermore, in the double container of the present invention, it is preferable that the outer layer is made of polyethylene terephthalate resin and the inner layer is made of polypropylene resin. [Effects of the Invention]

[0013] According to the double-layered container of the present invention, by providing an air layer between the outer layer and the inner layer, it is possible to reduce resistance when rotating the inner layer to release the connection with the outer layer, and the inner layer can be pulled out from the outer layer and easily peeled off for separation. In particular, in this invention, the air layer is provided from the lower end of the opening of the outer layer to the boundary position where it transitions to the body, so that, in combination with the rotation of the inner layer, it is easy to release the adhesion between the body and the bottom, and separation is easy. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a side view of one embodiment of a dual container according to the present invention; FIG. [Figure 2] FIG. 2 is a side cross-sectional view of the double container (cap not shown) shown in FIG. [Figure 3] 1(a) is a cross-sectional side view showing the state in which the inner layer body has been pulled out from the outer layer body in the double container shown in FIG. 1 (the cap is not shown), and FIG. 1(b) is a diagram showing how the outer layer body and the inner layer body are connected. DETAILED DESCRIPTION OF THE INVENTION

[0015] An embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a side view showing one embodiment of a double container according to the present invention, Fig. 2 is a side cross-sectional view of the double container shown in Fig. 1 (cap not shown), Fig. 3(a) is a side cross-sectional view showing the state in which the inner layer body has been pulled out from the outer layer body in the double container (cap not shown) shown in Fig. 1, and Fig. 3(b) is a diagram showing a method of connecting the outer layer body and the inner layer body.

[0016] Reference numeral 1 in FIGS. 1 to 3 denotes a double container according to the present invention, which is composed of an outer layer body 10 and an inner layer body 20 peelably laminated on the inside of the outer layer body 10.

[0017] The outer layer body 10 has a cylindrical opening 11 with an opening end 11a that opens upward, a shoulder 12 connected to the lower end of the opening 11, a body 13 connected to the lower end of the shoulder 12, and a bottom 15 connected to the lower end of the body 13 via a heel 14 that narrows in diameter downward.

[0018] The inner layer body 20 has a neck portion 21 that is exposed from the opening 11a of the outer layer body 10, and a wall portion 22 that is connected to the lower end of the neck portion 21 and is peelably laminated to the inner wall surfaces of the shoulder portion 12, body portion 13, heel portion 14, and bottom portion 15 of the outer layer body 10. A filling space S for the contents is formed inside the wall portion 22, and the contents in the filling space S can be poured out from the upper opening of the neck portion 21.

[0019] Here, "peeling" in this application includes not only the case where the inner layer body 20 and the outer layer body 10 separate from each other from an adhesive state, but also the case where the inner layer body 20 separates from the outer layer body 10 from a contact state where no adhesive force is present.

[0020] As shown in Fig. 1, a cap 2 is attached to the mouth / neck portion 21. The cap 2 has a cap body 2a that engages with an annular rib 21a provided on the outer circumferential surface of the mouth / neck portion 21 of the inner layer body 20, and a lid body 2c that is rotatably connected to the cap body 2a via a hinge 2b and opens and closes the upper opening of the mouth / neck portion 21. Note that the cap 2 is not limited to the one shown in the figure, and it may be attached to the mouth / neck portion 21 by screwing. Alternatively, a dispenser equipped with a pump mechanism may be attached to the mouth / neck portion 21 without providing the cap 2.

[0021] The mouth-neck portion 21 has a seal protrusion 21b below the annular rib 21a. As will be described later, when assembling the inner layer body 20 (inner layer preform) and the outer layer body 10 (outer layer preform), the inner layer body 20 is inserted until the lower surface of the seal protrusion 21b abuts against the opening end 11a of the outer layer body 10, thereby sealing the gap between the opening 11 and the mouth-neck portion 21 with the seal protrusion 21b. This makes it possible to prevent outside air from entering between the opening 11 and the mouth-neck portion 21, and to prevent deterioration of the quality of the contents due to outside air permeating into the inner layer body 20.

[0022] An air layer 3 is provided between the inner wall surface of region A, which extends from the lower end of the opening 11 of the outer layer body 10, through the shoulder portion 12, to a boundary position 16 where the outer layer body 10 transitions to the body portion 13, and the wall portion 22 of the inner layer body 20 laminated on the inner wall surface. Region A is the portion that is stretched when a double preform, which is a combination of an inner layer preform and an outer layer preform described below, is biaxially stretched and blow molded, and includes the maximum diameter portion of the shoulder portion 12 of the outer layer body 10 and the inner layer body 20 (wall portion 22) laminated thereon, which expands in diameter from top to bottom.

[0023] The air layer 3 is formed by providing a finely uneven region between the inner wall surface of the outer layer 10 in region A and the wall portion 22 of the inner layer 20, and the uneven region is formed by providing a rough surface portion by applying a finely uneven processing or a graining process to at least one of the inner wall surface of the outer layer 10 and the outer wall surface of the inner layer 20. If the rough surface portion (uneven region) is provided in the body 13 and bottom 14, for example, when the double container 1 is squeezed to dispense the contents, the inner layer 20 may easily peel off from the outer layer 10, which may result in poor appearance or poor dispensing. Therefore, it is preferable to provide the rough surface portion only in region A.

[0024] The surface roughness of the roughened surface portion of the double container 1 is preferably 1.2 μm or more and less than 2.2 μm, and in this embodiment, both the outer layer body 10 and the inner layer body 20 have roughened surface portions, and the surface roughness of the roughened surface portions falls within this range. If the surface roughness of the roughened surface portion is less than 1.2 μm, it is not possible to effectively reduce the rotational resistance between the outer wall surface of the outer layer body 10 and the wall portion 22 of the inner layer body 20 when rotating the inner layer body 20 to release the connection with the outer layer body 10, as described below. On the other hand, if the surface roughness is 2.2 μm or more, when the double container 1 is made of a transparent bottle, the roughened surface portion may be visually perceived as a scratch, resulting in poor appearance.

[0025] The double container 1 is formed by biaxially stretching blow molding a double preform, which is a combination of an outer layer preform (corresponding to outer layer 10) formed, for example, by injection molding biaxially stretchable polyethylene terephthalate (PET) resin and an inner layer preform (corresponding to inner layer 20) formed, for example, by injection molding polypropylene resin, linked at the mouth. The mouth of the outer layer preform (the portion that forms the opening 11 of outer layer 10) and the mouth of the inner layer preform (the portion that forms the neck 21 of inner layer 20) are non-stretched portions and are not stretched during biaxial stretching blow molding, and retain the same shape after molding as when the double preform was assembled.

[0026] The rough surface portion is preferably formed by roughening the outer surface of the inner layer preform, so that when biaxially stretched blow molding is performed, the rough surface portion formed on the inner layer preform can be transferred to the inner surface of the outer layer body 10. Alternatively, the rough surface portion may be formed by roughening the inner surface of a mold for the inner layer preform and then transferring this to the outer surface of the inner layer preform.

[0027] The outer layer 10 can be manufactured using a biaxially stretchable polyethylene terephthalate resin such as homo-PET. The material of the outer layer 10 is not limited to polyethylene phthalate resin, and it may be formed from a resin material such as polypropylene (PP) resin or polyethylene (PE) resin. Furthermore, the outer layer 10 is not limited to a single-layer structure, and may be formed from multiple layers in which a functional layer having barrier properties or the like is laminated in addition to a base layer.

[0028] The material of the inner layer body 20 can be selected appropriately so that the inner layer body 20 can be peeled from the outer layer body 10, in addition to polypropylene resin (homopolymer, random copolymer, block copolymer), and may be formed from, for example, polyethylene (PE) resin or biaxially stretchable polyethylene terephthalate resin. Furthermore, the inner layer body 20 is not limited to a single-layer structure, and may be formed from multiple layers in which a functional layer having barrier properties or the like is laminated in addition to a base material layer.

[0029] The means for connecting the opening 11 of the outer layer 10 and the neck portion 21 of the inner layer 20 is not particularly limited, but may be one consisting of a convex portion 23 provided on the outer surface of the neck portion 21 of the inner layer 20, as shown in Figure 3, and an L-shaped groove portion 17 provided on the inner surface of the opening 11 of the outer layer 10 and capable of fitting to the convex portion 23.

[0030] In this connecting means, as shown in Figure 3, the convex portion 23 on the outer peripheral surface of the mouth-and-neck portion 21 is fitted into the horizontal groove 17a of the L-shaped groove portion 17 on the inner peripheral surface of the opening 11, thereby connecting the mouth-and-neck portion 21 and the opening 11 in an inseparable manner. On the other hand, when separating the double-layered container 1 into the inner layer body 20 and the outer layer body 10, the mouth-and-neck portion 21 of the inner layer body 20 is grasped with the fingers and rotated around the axis O in the direction shown by the arrow in Figure 3(a). As shown in Figure 3(b), the convex portion 23 moves from the horizontal groove 17a of the groove portion 17 to the vertical groove 17b, thereby releasing the connection with the opening 11, and the mouth-and-neck portion 21 can be removed from the opening 11 by pulling it upward.

[0031] When the neck portion 21 is rotated as described above to release it from its connection with the opening 11, the air layer 3 is interposed between the inner wall surface of the outer layer 10 in region A and the wall portion 22 of the inner layer 20 laminated on that inner wall surface, reducing resistance during rotation, and the wall portion 22 of the inner layer 20 twists as the neck portion 21 rotates, allowing it to easily peel off from the outer wall surface of the outer layer 10. When the neck portion 21 is lifted up in this state, peeling progresses from the peeled portion in this order to the shoulder portion 12, body portion 13, heel portion 14, and bottom portion 15 of the outer layer 10, allowing the inner layer 20 to be easily peeled off from the outer layer 10.

[0032] Furthermore, the presence of the air layer 3 in the area A (the introduction of air) also makes it easier to release the adhesion between the body 13, heel 14 and bottom 15 below the area A, and the inner layer 20 can be easily peeled off from the outer layer 10, pulled out and separated. [Industrial Applicability]

[0033] The double container of the present invention can be suitably used as a container for storing contents that are difficult to recycle or reuse, such as oil-containing contents or contents other than food. [Explanation of symbols]

[0034] 1 double container 2 Caps 2a Cap body 2b hinge 2c Lid body 3 Air layer 10 Outer body 11 Opening 11a Open end 12 Shoulder 13 Torso 14 Heel 15 Bottom 16 Boundary position 17 Groove 17a Yokomizo 17b Vertical groove 20 Inner layer 21 Oral and cervical regions 21a Circular rib 21b Seal protrusion 22 Wall 23 Convex part Area A S filling space

Claims

1. an outer layer body having an opening with an open end that opens upward, a shoulder portion connected to the lower end of the opening, a body portion connected to the lower end of the shoulder, and a bottom portion connected to the lower end of the body portion via a heel portion; an inner layer body having an opening for pouring out the contents, the inner layer body having a neck portion exposed from the opening and detachably connected to the opening of the outer layer body, and a wall portion connected to the lower end of the neck portion and peelably laminated on the inner wall surface of the outer layer body over a region from the end of the opening of the outer layer body to the bottom, the inner side surrounded by the wall portion being a filling space for the contents; A double container in which the connection between the neck portion and the opening is released, and then the inner layer body can be removed from the outer layer body by lifting up the neck portion, A double container characterized in that an air layer is formed by a fine uneven area between the inner wall surface of the outer layer body and the wall portion of the inner layer body laminated on the inner wall surface, and serves as a starting point when peeling the inner layer body from the outer layer body.

2. A double container as described in claim 1, characterized in that the air layer is provided between the inner wall surface of the outer layer body from the lower end of the opening to the boundary position where it transitions to the body portion and the wall portion of the inner layer body laminated on the inner wall surface.

3. 3. A double container according to claim 1, wherein the uneven area is formed by providing a rough surface on either or both of the inner wall surface of the outer layer and the wall of the inner layer.

4. The double container described in claim 3, characterized in that the rough surface portion is formed by roughening either one or both of the inner layer preform and the outer layer preform of a double preform consisting of an inner layer preform and an outer layer preform used when molding a double container using a biaxially stretched blow molding method.

5. 4. The double container according to claim 3, wherein the surface roughness of the rough surface portion is 1.2 μm or more and less than 2.2 μm.

6. 3. The double container according to claim 1, wherein the outer layer is made of polyethylene terephthalate resin, and the inner layer is made of polypropylene resin.

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