JP2021172404A - Method for producing double structure container - Google Patents

Abstract

To enable inflow of air into a gap between an outer container and an inner container not to be prevented in a double structure container having the outer container that forms an outer shell of the container and the inner container that shrinks and is deformed as a stored content is reduced, and that includes a storage part detachable from the outer container.SOLUTION: An inner mouth part 31 is held on a radially inner side of a mouth part 21 of an external preform 20 with a predetermined space so that a ventilation path H is formed, and when blowing and molding an internal preform 30 inserted into the inner side of the external preform 20 integrally with the external preform 20, air is blown into the space between the mouth part 21 and the inner mouth part 31 so as to separate a portion where the internal preform 30 is extended from a portion where the external preform 20 is extended, thereby, a gap G is formed at least between a diameter expanding start area 21c of an outer container 2 and a storage part 32 of an inner container 3.SELECTED DRAWING: Figure 6

Description

The present invention relates to a method for producing a double-structured container.

Conventionally, a double-structured container including an outer container that can be elastically deformed and an inner container that contracts and deforms as the contents decrease is known (see, for example, Patent Document 1). In such a double-structured container, the quality of the contents can be maintained by blocking the inflow of air into the inner container after pressing and discharging the contents.

Japanese Unexamined Patent Publication No. 6-39906

By the way, in this kind of double-structured container, after squeezing and discharging the contents, air flows between the outer container and the inner container, so that the inner container that has been shrunk and deformed is released from the outer container. While peeling off, the outer container is restored to its original shape. Therefore, it is necessary to prevent the inflow of air between the outer container and the inner container from being obstructed.

In view of these circumstances, the present inventors have made extensive studies to prevent the inflow of air between the outer container and the inner container of this type of double-structured container from being obstructed. , The present invention has been completed.

The method for manufacturing a double-structured container according to the present invention includes an outer container that forms an outer shell of the container, and a storage portion that shrinks and deforms as the contained contents decrease and can be peeled off from the outer container. A method for manufacturing a double-structured container including an inner container, in which an outer preform molded into a bottomed tubular shape having one end having a mouth portion and a bottomed tubular shape having one end having an inner mouth portion are molded. The inner mouth portion is held at a predetermined interval so that a ventilation path is formed inside the mouth portion of the outer preform, and the inner mouth portion is inserted inside the outer preform. The outer preform and the inner preform are integrated so that the reform is set in a blow molding mold, the outer preform is molded into the outer container, and the inner preform is molded into the inner container. When the blow molding is performed, air is blown between the mouth portion of the outer preform and the inner mouth portion of the inner preform, and the inner preform is stretched from the portion where the outer preform is stretched. There is a method of forming a gap between the inner container and the accommodating portion, at least in the area where the diameter expansion starts below the mouth portion of the outer container, by pulling the separated portions apart.

According to the present invention, by forming a gap with the accommodating portion of the inner container at least in the diameter expansion start region below the mouth portion of the outer container, when the contents are discharged, the gap is used as a starting point. It is possible to manufacture a double-structured container in which the accommodating portion of the inner container is surely peeled off from the outer container and the inflow of air between the outer container and the inner container is not hindered.

It is a vertical cross-sectional view which shows typically an example of the double-structured container to be manufactured in the manufacturing method of the double-structured container which concerns on embodiment of this invention. It is a vertical cross-sectional view which shows typically an example of the preform used in the manufacturing method of the double-structured container which concerns on embodiment of this invention. It is the AA end view of FIG. It is explanatory drawing which shows typically one step of the manufacturing method of the double structure container which concerns on embodiment of this invention. It is explanatory drawing which shows typically one step of the manufacturing method of the double structure container which concerns on embodiment of this invention. It is explanatory drawing which shows typically one step of the manufacturing method of the double structure container which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a vertical cross-sectional view schematically showing an example of a double-structured container manufactured by the method for manufacturing a double-structured container according to the present embodiment.

The container 1 shown in FIG. 1 has an outer container 2 that can be restored to its original shape by elastic deformation when the contents are squeezed and discharged, and an outer container 2 that shrinks and deforms as the contained contents decrease and is outer. It includes an inner container 3 including an accommodating portion 32 that can be peeled off from the container 2.
Note that FIG. 1 schematically shows a state in which the accommodating portion 32 is contracted and deformed by a two-dot chain line.

The outer container 2 is formed into a predetermined container shape including a mouth portion 21, a shoulder portion 22, a body portion 23, and a bottom portion 24 to form an outer shell of the container 1.
The mouth portion 21 of the outer container 2 is a cylindrical portion to which a discharge cap (not shown) is attached. A fitting portion 21a for mounting the discharge cap by tapping is provided on the opening end side of the mouth portion 21, but the means for mounting the discharge cap is not limited to this. For example, it may be attached by screwing.
Further, an annular neck ring 21b protruding outward along the circumferential direction is provided on the lower end side of the mouth portion 21, and the lower neck portion 21c below the neck ring 21b expands toward the body portion 23. For the first time in diameter, it is connected to the shoulder portion 22 that connects the mouth portion 21 and the body portion 23.

Here, in the present invention, the vertical / horizontal and vertical / horizontal directions are defined in the state shown in FIG. 1 with the mouth portion 21 facing up, and the mouth portion 21 is similarly used for the preform 10 described later. In the state shown in FIG. 2 above, the vertical and horizontal directions and the vertical and horizontal directions shall be defined.

The inner container 3 is arranged inside the outer container 2 in a state where the inner mouth portion 31 connected above the accommodating portion 32 is held inside the mouth portion 21 of the outer container 2 in the radial direction at a predetermined interval. It is installed. In the illustrated example, the flange portion 31a projecting along the circumferential direction from the outer peripheral surface of the inner mouth portion 31 is held by the step portion 21d formed along the circumferential direction on the inner peripheral surface of the mouth portion 21 of the outer container 2. Has been done. At that time, by forming a notch portion 31b on the peripheral edge of the flange portion 31a, a ventilation passage H is formed between the outer peripheral surface and the inner peripheral surface of the mouth portion 21 of the outer preform 20 (described later). (See FIG. 3).
Then, in the accommodating portion 32 of the inner container 3, a gap G is formed between the lower neck portion 21c below the neck ring 21b of the outer container 2, that is, the diameter expansion start region 21c below the mouth portion 21 of the outer container 2. As described above, the outer container 2 is detachably joined to the inner surfaces of the shoulder portion 22, the body portion 23, and the bottom portion 24.

The discharge cap attached to the mouth portion 21 of the outer container 2, for example, when the container 1 is squeezed with the discharge port side facing down, the discharge port can be opened to discharge the contents, and the container 1 can be discharged. When the squeezing force is weakened, the discharge port is closed to block the inflow of air into the inner container 3, while the air can flow between the outer container 2 and the inner container 3 and the outer container 3 is used. The specific configuration thereof is not particularly limited as long as it can suppress the leakage of the air flowing between the inner container 3 and the inner container 3.

In such a container 1, after squeezing and discharging the contents, air flows between the outer container 2 and the inner container 3, so that the accommodating portion 32 of the inner container 3 that has been contracted and deformed is formed. The outer container 2 is restored to its original shape while being peeled off from the outer container 2. As a result, the intrusion of air into the inner container 3 in which the contents are housed is blocked, and the contact between the contents and the air is reduced, so that the quality of the contents can be maintained. Therefore, it is necessary to prevent the inflow of air between the outer container 2 and the inner container 3 from being obstructed, and if the inflow of air is obstructed, the outer container 2 will not be restored to its original shape. It ends up.

In the present embodiment, at least in the diameter expansion start region 21c below the mouth portion 21 of the outer container 2, a gap G is formed between the inner container 3 and the accommodating portion 32 to squeeze and discharge the contents. At this time, the accommodating portion 32 of the inner container 3 is surely separated from the outer container 2 starting from the gap G, whereby the inflow of air between the outer container 2 and the inner container 3 is hindered. The outer container 2 is satisfactorily restored to its original shape.

Next, a method for manufacturing a double-structured container according to the present embodiment in which such a container 1 is a manufacturing target will be described.
FIG. 2 is a vertical cross-sectional view schematically showing an example of a preform used in the method for manufacturing a double-structured container according to the present embodiment, and FIG. 3 is a cross-sectional view taken along the line AA of FIG.

The preform 10 shown in these figures includes an outer preform 20 and an inner preform 30 inserted inside the outer preform 20.
The outer preform 20 is formed into a bottomed cylindrical shape having a mouth portion 21 on one end side, and an annular neck ring 21b protruding outward along the circumferential direction is provided on the lower end side of the mouth portion 21. There is. The inner preform 30 is formed into a bottomed tubular shape having an inner mouth portion 31 on one end side, and the inner mouth portion 31 has a ventilation passage H formed inside the mouth portion 21 of the outer preform 20 in the radial direction. It is held inside the outer preform 20 at predetermined intervals so as to be inserted inside the outer preform 20.

To ensure that the inner mouth portion 31 of the inner preform 30 is held radially inside the mouth portion 21 of the outer preform 20 at a predetermined interval, for example, the inner mouth portion 31 of the inner preform 30 The flange portion 31a projecting along the circumferential direction on the outer peripheral surface can be held by the step portion 21d formed along the circumferential direction on the inner peripheral surface of the mouth portion 21 of the outer preform 20. , Not limited to this.

Further, in the illustrated example, the notch portion 31b is formed on the peripheral edge of the flange portion 31a so that the air passage H that allows the inflow of air is formed, but the present invention is not limited to this. For example, a vertical groove may be formed on the inner peripheral surface of the mouth portion 21 of the outer preform 20 so that the ventilation path H is formed between the outer peripheral surface and the peripheral edge of the flange portion 31a.

The mouth portion 21 of the outer preform 20 and the inner mouth portion 31 of the inner preform 30 are not stretched during blow molding as described later, and are substantially as they are in the outer container 2 in the container 1 described above. Since the mouth portion 21 and the inner mouth portion 31 of the inner container 3 are the same, the same reference numerals are given to the parts common to the container 1 and the preform 10.

The outer preform 20 and the inner preform 30 included in the preform 10 are formed into a predetermined shape by injection molding, compression molding, or the like using a thermoplastic resin. As the thermoplastic resin, any resin capable of blow molding can be used. Specifically, thermoplastic polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, amorphous polyarylate, polylactic acid, polyethylene furanoate or copolymers thereof can be used, and in particular, ethylene terephthalate such as polyethylene terephthalate can be used. Based thermoplastic polyester can be preferably used. Two or more of these resins may be mixed, or other resins may be blended. Polycarbonate, acrylonitrile resin, polypropylene, propylene-ethylene copolymer, polyethylene, etc. can also be used.
Further, the outer preform 20 and the inner preform 30 are not limited to being molded into a single layer, but can also be molded into multiple layers including a gas barrier layer or the like, if necessary.

The preform 10 is required to be set in the blow molding mold 100 as shown in FIG. 4 after each of the outer preform 20 and the inner preform 30 is softened by heating to enable blow molding. It is stretched in the axial direction (longitudinal direction) by a stretching rod (not shown), and is stretched in the axial direction and the circumferential direction (horizontal direction) by the high-pressure blow air supplied from the blowout port 102 of the blow nozzle 101.

As a result, the outer preform 20 and the inner preform 30 are integrated so that the outer preform 20 is formed into the outer container 2 of the container 1 and the inner preform 30 is formed into the inner container 3 of the container 1. Is blow-molded. That is, the outer preform 20 is formed into the outer container 2 that forms the outer shell of the container 1 by extending the portion below the mouth portion 21 and transferring the cavity shape of the blow molding mold 100. On the other hand, in the inner preform 30, the portion below the inner mouth portion 31 is stretched integrally with the portion below the mouth portion 21 of the outer preform 20, and is detachably joined to the inner surface of the outer container 2. It is molded into the housing portion 32.

In the present embodiment, when the preform 10 is blow-molded in this way, the mouth portion 21 of the outer preform 20 and the inner mouth portion 31 of the inner preform 30 are separated from the blow air outlet 102. A blow nozzle 101 having a second outlet 103 opened between the two is used. Then, at the time of blow molding, air is blown from the second outlet 103 between the mouth portion 21 of the outer preform 20 and the inner mouth portion 31 of the inner preform 30, and the portion where the outer preform 20 is stretched. By pulling away the stretched portion of the inner preform 30, a gap G is formed between the inner preform 30 and the accommodating portion 32 of the inner container 3 at least in the diameter expansion start region 21c below the mouth portion 21 of the outer container 2. (See FIGS. 5 and 6).
In FIGS. 5 and 6, the blow air is indicated by an arrow A1, and the air blown between the mouth portion 21 of the outer preform 20 and the inner opening portion 31 of the inner preform 30 is indicated by an arrow A2.

The timing of blowing air between the mouth portion 21 of the outer preform 20 and the inner mouth portion 31 of the inner preform 30 can be appropriately adjusted so as not to hinder the molding of the container 1. For example, the timing at which the blow air pressure remains to some extent after the portion below the inner mouth portion 31 of the inner preform 30 and the portion below the mouth portion 21 of the outer preform 20 are sufficiently stretched. It is preferable to blow in with. If the residual pressure of blow air is insufficient, the accommodating portion 32 of the molded inner container 3 may be deformed so as to be crushed. It is preferable to determine the optimum timing together with the arrangement of the outlet 103, the direction in which the air is blown, the flow rate and pressure of the blown air, and the like.
It should be noted that the air blown from the second outlet 103 is blown between the mouth portion 21 of the outer preform 20 and the inner mouth portion 31 of the inner preform 30 without leaking to the outside. It is preferable to provide a sealing mechanism (not shown) between the mouth portion 21 of the reform 20 and / or the inner mouth portion 31 of the inner preform 30 and the blow nozzle 101.

As described above, according to the present embodiment, at least in the diameter expansion start region 21c below the mouth portion 21 of the outer container 2, a gap G is formed between the inner container 3 and the accommodating portion 32. When discharging an object, the accommodating portion 32 of the inner container 3 is surely peeled off from the outer container 2 starting from the gap G, and the inflow of air between the outer container 2 and the inner container 3 is hindered. It is possible to manufacture a double-structured container without a container.

Although the present invention has been described above with reference to preferred embodiments, it goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention. Nor.

For example, in the above-described embodiment, an example in which the entire container 1 is formed to have a substantially cylindrical shape has been illustrated and described, but the specific shape of the container 1 is not particularly limited.
Further, in the above-described embodiment, an example in which the outer container 2 is elastically deformable and the contents are discharged by squeezing has been described, but in the present invention, the outer container 2 is not elastically deformed and the pressure difference is obtained. It can also be applied to a double-structured container in which the contents are discharged (sucked) from the accommodating portion 32 of the inner container 3. Even in such a case, since the inflow of air between the outer container 2 and the inner container 3 is not hindered, the accommodating portion 32 of the inner container 3 becomes smaller as the contents are reduced. It is possible to ensure that the outer container 2 is peeled off while contracting and deforming.

1 container (double structure container)
2 Outer container 20 Outer preform 21 Mouth 21b Neck ring 21c Diameter expansion start area 21d Step 3 Inner container 30 Inner preform 31 Inner mouth 31a Flange 31b Notch 32 Storage 100 Blow molding type

Claims (2)

A method for manufacturing a double-structured container including an outer container that forms the outer shell of the container and an inner container that is contracted and deformed as the contained contents decrease and includes an inner container that can be peeled off from the outer container. There,
An outer preform molded into a bottomed cylinder with one end as the mouth,
It is formed into a bottomed tubular shape with one end side as an inner mouth portion, and the inner mouth portion is held at predetermined intervals so that a ventilation path is formed inside the mouth portion of the outer preform in the radial direction. Then, the inner preform inserted inside the outer preform is set in the blow molding mold, and then
When the outer preform and the inner preform are integrally blow-molded so that the outer preform is molded into the outer container and the inner preform is molded into the inner container.
Air is blown between the mouth portion of the outer preform and the inner mouth portion of the inner preform to separate the stretched portion of the inner preform from the stretched portion of the outer preform. By
A method for producing a double-structured container, characterized in that a gap is formed between the inner container and the inner container at least in a diameter expansion start region below the mouth portion of the outer container. A flange portion is formed on the outer peripheral surface of the inner mouth portion of the inner preform along the circumferential direction, and the flange portion is formed along the circumferential direction on the inner peripheral surface of the mouth portion of the outer preform. The method for manufacturing a double-structured container according to claim 1, wherein the double-structured container is held in the formed step portion.

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