JP2020193021A - Double container and method for manufacture thereof - Google Patents

Abstract

To provide a double container in which an air passage can be reliably ensured from an outside air introduction port toward between a shank and a storage part, and a method for manufacture of the same.SOLUTION: A double container 1 has an outer layer body 10 and an inner layer body 20, and an outside air introduction port 14 is provided on a mouth 33 which is configured from an outer mouth part 11 and an inner mouth part 21. The outer layer body 10 has a bulge part 30 which is formed in such a manner that a connection part between the outer mouth part 11 and a shoulder 12 bulges outside the container.SELECTED DRAWING: Figure 1

Description

The present invention relates to a double container and a method for producing the same.

A preform assembly that incorporates the inner preform inside the outer preform as a container for storing food seasonings such as soy sauce, beverages, cosmetics such as lotion, and toiletries such as shampoo, conditioner, and liquid soap. An outer layer body having a tubular outer opening portion and a bottomed tubular body portion connected to the outer opening portion via a shoulder portion, and an inner opening portion arranged inside the outer opening portion. A double container formed in a double structure is known to have an inner layer body which is connected to the inner mouth portion and has a volume-reducing deformable accommodating portion which is detachably laminated on the inner surface of the shoulder portion and the body portion. (See, for example, Patent Document 1).

The double container is used, for example, as a squeeze type pouring container combined with a pouring cap equipped with a check valve or a container with a pump combined with a pump. In this case, the content liquid can be discharged to the outside by squeezing (squeezing) the body of the outer layer body or operating the pump, while after the content liquid is discharged, the outer layer body is discharged from the outside air inlet. By introducing outside air between the inner layer and the inner layer, only the outer layer can be restored to its original shape while the accommodating portion of the inner layer is reduced in volume and deformed. Therefore, according to the double container, the content liquid contained in the accommodating portion of the inner layer body can be discharged to the outside without replacing the outside air, so that the content liquid contained inside the inner layer body can be discharged to the outside. It is possible to reduce the contact of the outside air with the content liquid and suppress deterioration and deterioration of the content liquid.

JP-A-2017-178434

However, in the double container formed by blow-molding the preform assembly in which the inner preform is incorporated inside the outer preform as in the conventional double container, the space between the outer layer body and the inner layer body is formed. If the outside air inlet for introducing outside air is provided in the mouth composed of the outer mouth and the inner mouth, it is difficult to secure the airway from the outside air inlet to the shoulder and the accommodating part. After pouring out the contents, the outside air is not introduced between the shoulder and the accommodating part and between the body and the accommodating part, and the volume reduction deformation of the accommodating part is not maintained, or the restoration of the outer layer is hindered. There was a problem that there was a risk that it would end up.

The present invention has been made in view of such a problem, and an object of the present invention is to ensure that an airway can be secured from an outside air introduction port provided in a mouth portion to a space between a body portion and a housing portion. The purpose is to provide a double container and a method for producing the same.

The double container of the present invention has an outer layer body including a tubular outer mouth portion and a bottomed tubular body portion connected to the outer mouth portion via a shoulder portion, and a tubular inner mouth portion and the inner mouth portion. It has an inner layer body that is connected to the portion and has a volume-reducing and deformable accommodating portion that is detachably laminated on the inner surface of the shoulder portion and the body portion, and communicates between the outer layer body and the inner layer body. The outside air introduction port is provided in the mouth portion composed of the outer mouth portion and the inner mouth portion arranged inside the outer mouth portion, and the outer layer body is the outer mouth portion and the shoulder portion. It is characterized in that the connecting portion has a bulging portion formed by projecting to the outside of the container.

In the above configuration, the double container of the present invention corresponds to a range in which the inner layer body projects radially outward from the outer surface of the inner layer body and extends from the outer mouth portion to the bulging portion of the outer layer body. It is preferable to have ridges extending in the vertical direction.

In the double container of the present invention, in the above configuration, ribs extending in the vertical direction formed by locally projecting inside the container or outside the container are provided on the shoulder portion of the outer layer body. preferable.

The method for producing a double container of the present invention includes an outer preform having a tubular outer mouth portion and an extending portion connected to the outer opening portion, and a tubular inner opening portion and an extending portion connected to the inner opening portion. A preform forming step of individually forming an inner preform including the above, and an inner surface of a portion of the outer preform that extends from the outer opening portion to the extending portion by arranging the inner preform inside the outer preform. The outer preform is formed by a preform assembly process in which a gap is provided between the inner preform and the outer surface of the inner preform, and blow molding by arranging the preform assembly in a mold. It has a blow molding step of forming a double container having an outer layer body corresponding to the above and an inner layer body corresponding to the inner preform, and the outer layer body has a body portion connected to an outer mouth portion via a shoulder portion. However, by providing a recess on the inner surface of the mold, a bulging portion projecting to the outside of the container is formed at the connecting portion between the outer opening portion and the shoulder portion in the outer layer body.

In the method for producing a double container of the present invention, in the above configuration, the inner preform projects radially outward from the outer surface of the inner preform and extends from the outer opening portion to the extending portion of the outer preform. It is preferable to have ridges extending in the vertical direction so as to correspond to the range.

In the method for producing a double container of the present invention, in the above configuration, it is preferable to provide ridges or dents extending in the vertical direction on a portion of the inner surface of the mold corresponding to the shoulder portion.

According to the present invention, it is possible to provide a double container and a method for manufacturing the same, which can surely secure an airway from an outside air introduction port provided in a mouth portion to a space between a body portion and a housing portion.

It is a half cross-sectional view which shows the main part of the double container which is one Embodiment of this invention. It is a top view of the double container shown in FIG. It is a half cross-sectional view which shows the modification of the double container shown in FIG. It is a top view of the double container shown in FIG. It is a half cross-sectional view of the preform assembly blow-molded into the double container shown in FIG.

Hereinafter, an embodiment of the present invention will be illustrated and described with reference to the drawings.

The double container 1 according to the embodiment of the present invention shown in FIG. 1 is made of synthetic resin, which is also called a laminated peeling container or a delamination container (derami container), and has an outer layer body 10 and an inner layer body 20. It has a double structure. The double container 1 can be formed by biaxially stretching blow molding the preform assembly 40 (preform assembly according to the embodiment of the present invention) shown in FIG. Hereinafter, a case where the double container 1 is used as a squeeze-type pouring container for containing a liquid such as a cosmetic or a food seasoning as a content will be described.

As shown in FIG. 1, the outer layer body 10 is a portion constituting the outer shell of the double container 1, and has a bottle shape including an outer mouth portion 11, a shoulder portion 12, and a body portion 13.

The outer opening portion 11 has a cylindrical shape centered on the central axis O. A male screw 11a is integrally provided on the outer peripheral surface of the outer opening portion 11, so that a pouring cap (not shown) having a spout can be screwed to the male screw 11a and attached to the outer opening portion 11. It has become.

The vertical direction means a direction along the central axis O, the upper direction means a direction from the body portion 13 to the outer mouth portion 11, and the lower direction means the opposite direction. The radial direction means a direction orthogonal to the central axis O, and the circumferential direction means a direction orbiting the central axis O. The vertical cross section means a cross section including the central axis O, and the cross section means a cross section perpendicular to the central axis O.

The outer opening portion 11 may be provided with an annular protrusion instead of the male screw 11a, and may be attached by engaging the injection cap in an undercut shape with a stopper.

The outer port portion 11 is provided with two outside air introduction ports 14. The two outside air introduction ports 14 are arranged symmetrically on both sides of the outer port portion 11 with the central axis O sandwiched between them, and are formed in an elongated hole shape extending in the circumferential direction and penetrate the outer port portion 11 in the radial direction. There is. That is, each outside air introduction port 14 is composed of a through hole penetrating the outside port portion 11. Each outside air introduction port 14 communicates between the outer layer body 10 and the inner layer body 20, and outside air can be introduced between the outer layer body 10 and the inner layer body 20. The number, arrangement, and shape of the outside air introduction ports 14 are not limited to this, and can be appropriately designed. For example, the outside air introduction port 14 may have a perfect circular shape.

A neck ring 11b is integrally provided on the outer peripheral surface of the outer port portion 11 on the side of the shoulder portion 12 with respect to the outside air introduction port 14. The neck ring 11b has a flange shape extending over the entire circumference of the outer opening portion 11, and projects outward from the outer peripheral surface of the outer opening portion 11 in the radial direction. The neck ring 11b is provided slightly above the lower end of the outer opening portion 11. That is, in the present embodiment, a cylindrical non-stretched portion that is not substantially stretched during biaxial stretch blow molding is provided directly below the neck ring 11b, and the lower end of the outer opening portion 11 is provided at this non-stretched portion. Consists of. By providing the non-stretched portion directly under the neck ring 11b in this way, the neck ring 51b can be prevented from being affected by stretching. The lower end of the outer opening portion 11 may be formed by the neck ring 11b without providing such a non-stretched portion.

The shoulder portion 12 is integrally connected to the lower end of the outer opening portion 11 and projects radially outward with respect to the outer opening portion 11. In the present embodiment, the vertical cross-sectional shape of the shoulder portion 12 is a curved shape that is convex outward of the container as a whole, but is not limited to this, for example, the upper portion is convex inward of the container and the lower portion is convex outward of the container. It may have a curved shape, or it may have a straight shape as a whole. Further, a bulging portion 30, which will be described later, is formed at the connecting portion between the outer opening portion 11 and the shoulder portion 12.

As shown in FIG. 1, the body portion 13 is formed in a bottomed tubular shape, and is integrally connected to the lower end of the shoulder portion 12 at the upper end thereof. That is, the body portion 13 is connected to the outer mouth portion 11 via the shoulder portion 12. The cross-sectional shape of the body portion 13 may be circular, or may be elliptical or substantially rectangular. Further, the body portion 13 may have a circumferential rib extending in the circumferential direction, or may have a decompression absorption panel or the like.

The body portion 13 has flexibility, and can be elastically deformed and dented by being squeezed (squeezed), and can be restored from the dented state by the elastic force to the original shape by itself. By making the body portion 13 elastically deformable by squeeze, when the double container 1 is used as a squeeze type pouring container, it is possible to easily perform the pouring operation of the content liquid. A double container that allows the outer layer 10 to be easily restored to its original shape after the content liquid is poured so that the outside air is surely introduced between the outer layer 10 and the inner layer 20 through the outside air introduction port 14. The function as 1 can be surely exhibited.

The bottom portion of the lower end of the body portion 13 has, for example, an annular outer peripheral edge having a concave shape inside, and the double container 1 can be arranged in an upright posture by grounding the bottom portion.

In the present embodiment, the outer layer body 10 is made of polyethylene terephthalate (PET). By making the outer layer body 10 made of polyethylene terephthalate, the double container 1 can be made a lightweight and highly transparent container.

The material of the outer layer 10 is not limited to polyethylene terephthalate, and for example, polyester resin, polyolefin resin, nylon resin, polycarbonate resin (PC resin), cycloolefin copolymer resin (COC resin), cycloolefin polymer resin (COP resin). Other synthetic resin materials such as, etc. can also be adopted. The outer layer body 10 may have a multi-layer structure in which a plurality of resin layers are provided.

The inner layer body 20 has an inner opening portion 21 and an accommodating portion 22 integrally connected to the lower end of the inner opening portion 21.

The inner opening portion 21 has a stepped cylindrical shape, and is arranged coaxially with the outer opening portion 11 inside the outer opening portion 11. The inner opening portion 21 has an annular flange 21a placed on the upper end of the outer opening portion 11, a cylindrical upper cylinder 21b that hangs down from the inner peripheral edge of the flange 21a and is in contact with the inner surface of the outer opening portion 11, and an upper cylinder 21b. It has a conical inclined cylinder 21c whose diameter is reduced downward from the lower end of the cylinder 21b, and a cylindrical lower cylinder 21d hanging from the lower end of the inclined cylinder 21c. The upper end of the inclined cylinder 21c is located above the upper ends of the two outside air introduction ports 14. A gap (ventilation path) 23 is formed between the inner surface of the outer opening portion 11 and the outer surface of the lower cylinder 21d of the inner opening portion 21.

The outer peripheral surface of the upper cylinder 21b abuts on the inner peripheral surface of the outer opening portion 11 over the entire circumference, so that the gap 23 is closed to the outside at the outer opening portion 11 or the upper end portion of the inner opening portion 21. There is. When the flange 21a comes into contact with the upper end of the outer opening portion 11, the inner opening portion 21 is positioned in the vertical direction with respect to the outer opening portion 11.

The accommodating portion 22 is formed in a bag shape thinner than the body portion 13, is connected to the lower end of the lower cylinder 21d of the inner opening portion 21, and extends along the inner surfaces of the shoulder portion 12 and the body portion 13. The inside of the accommodating portion 22 is a storage space for the content liquid, and the content liquid can be filled in the accommodating portion 22 through the inner mouth portion 21 and the content liquid stored in the accommodating portion 22 through the inner mouth portion 21. Can be dispensed to the outside. The accommodating portion 22 can be deformed (deformed so as to reduce the internal volume) while being peeled from the inner surface of the body portion 13 as the content liquid is poured out. At this time, by introducing outside air between the outer layer body 10 and the inner layer body 20 from the outside air introduction port 14, only the body portion 13 is restored to its original shape, and the accommodating portion 22 is peeled off from the inner surface of the body portion 13. And the volume can be reduced and deformed. In addition, the "peeling" in the present application is not only when the outer layer body 10 and the inner layer body 20 are separated from the adhesive state or the pseudo-adhesive state where the adhesive force hardly intervenes, but also when the outer layer body 10 and the outer layer body 10 are separated from the adhesive state where the adhesive force does not intervene. It also includes the case where the inner layer 20 is separated from the inner layer 20.

In the present embodiment, the inner layer 20 is made of polyethylene terephthalate. By making the inner layer 20 made of polyethylene terephthalate, the double container 1 can be made a lightweight and highly transparent container.

The material of the inner layer 20 is not limited to polyethylene terephthalate, and for example, polyester resin, polyolefin resin, nylon resin, polycarbonate resin (PC resin), cycloolefin copolymer resin (COC resin), cycloolefin polymer resin (COP resin). , Other synthetic resin materials such as ethylene-vinyl alcohol copolymer resin (EVOH resin) can also be adopted. When an ethylene-vinyl alcohol copolymer resin is used as the material of the inner layer body 20, an ethylene-vinyl alcohol copolymer resin having an appropriate ethylene content can be adopted in consideration of barrier properties and flexibility. The inner layer body 20 may have a multi-layer structure in which a plurality of resin layers are provided. For example, the inner layer body 20 may have a multilayer structure in which a barrier layer such as an MX nylon resin layer is provided between two polyethylene terephthalate layers in order to secure the barrier property.

In order to facilitate securing an airway for outside air from the outside air introduction port 14 to the body 13 and the accommodating portion 22, the inner layer 20 projects radially outward from the outer surface of the inner layer 20 and is an outer layer. A plurality of (six) ridges 24 extending in the vertical direction are integrally provided so as to correspond to the range extending from the outer mouth portion 11 to the shoulder portion 12 in 10. Here, "extending" to correspond to the range extending from the outer mouth portion 11 to the shoulder portion 12 means extending "to face" the range extending from the outer opening portion 11 to the shoulder portion 12. doing.

The plurality of ridges 24 are provided side by side at equal intervals in the circumferential direction. The plurality of ridges 24 are arranged so as to avoid the pair of outside air introduction ports 14, but the present invention is not limited to this, and the plurality of ridges 24 may be arranged so as to overlap the two outside air introduction ports 14.

Each of the ridges 24 extends from a height position corresponding to the outside air introduction port 14 to a position beyond the neck ring 11b and reaching a bulging portion 30. That is, each of the ridges 24 extends in the vertical direction so as to extend from the lower surface (outer surface) of the inclined cylinder 21c to a portion having a height corresponding to the bulging portion 30 in the accommodating portion 22. In the accommodating portion 22, the height of protrusion of the inner layer body 20 of the ridge 24 from the outer surface gradually decreases. The lower end of each ridge 24 is located at the upper end of the bulge 30. The number, arrangement, and shape of the ridges 24 are not limited to this, and can be appropriately designed. For example, the position of the upper end of each ridge 24 may be below the lower surface of the inclined cylinder 21c, and the position of the lower end of each ridge 24 may be above or below the height corresponding to the upper end of the bulge 30. It may be. The positions of the upper ends of the respective ridges 24 do not have to be the same height as each other. Further, the positions of the lower ends of the respective ridges 24 do not have to be the same height as each other.

As shown in FIGS. 1 and 2, in order to facilitate securing an airway for outside air from the outside air introduction port 14 to the body portion 13 and the accommodating portion 22, the shoulder portion 12 of the outer layer body 10 is in the vertical direction. A plurality of (16) ribs 25 extending to the surface are provided. In the present application, the rib means a portion extending in the longitudinal direction formed by locally projecting the outer layer body 10 to the inside or the outside of the container. In FIGS. 1 and 2, only one rib 25 is designated for convenience.

The plurality of ribs 25 are provided side by side at equal intervals in the circumferential direction. Each rib 25 extends from the upper end of the shoulder portion 12 to the lower end of the shoulder portion 12, and extends along the radial direction in the top view. Each rib 25 is a concave rib having a concave shape when viewed from the outside of the container. Each rib 25 has a U-shaped cross-sectional shape in which the width gradually narrows inward in the radial direction in the cross section over substantially the entire length. The inner layer 20 is also stretched by biaxial stretch blow molding so as to follow the shape of the rib 25. The number, arrangement and shape of the ribs 25 are not limited to this, and can be appropriately designed. For example, each rib 25 may be a convex rib having a convex shape when viewed from the outside of the container. Further, the position of the upper end of each rib 25 may be lower than the upper end of the shoulder portion 12, and the position of the lower end of each rib 25 may be above or below the lower end of the shoulder portion 12. The positions of the upper ends of the respective ribs 25 do not have to be the same height as each other. Further, the positions of the lower ends of the ribs 25 do not have to be the same height as each other.

In the present embodiment, in order to surely secure an airway from the outside air introduction port 14 to the body portion 13 and the accommodating portion 22, the outer layer body 10 is connected to the outer port portion 11 and the shoulder portion 12. A bulging portion 30 formed by projecting the portion to the outside of the container is integrally provided. Here, the bulging portion 30 is "formed by projecting the connecting portion between the outer opening portion 11 and the shoulder portion 12 to the outside of the container", that at least the connecting portion has the bulging portion 30. It means that you are. It is preferable that the bulging portion 30 extends from the connecting portion between the outer opening portion 11 and the shoulder portion 12 toward the shoulder portion 12 side as in the present embodiment.

The bulging portion 30 has an upper wall 31 that is integrally connected to the lower end of the outer opening portion 11 (the connecting portion between the outer opening portion 11 and the shoulder portion 12), and is hung from the outer peripheral edge of the upper wall 31 and integrated with the shoulder portion 12. It has a peripheral wall 32 connected to the above. That is, the bulging portion 30 is provided at the upper end portion of the shoulder portion 12. The upper wall 31 is configured to be inclined downward toward the outside in the radial direction, but the present invention is not limited to this, and the upper wall 31 may be configured to be inclined upward toward the outside in the radial direction or toward the outside in the radial direction. It may be configured so that it does not tilt in the vertical direction (extends horizontally). The peripheral wall 32 is configured so as not to be inclined in the radial direction (extending vertically) toward the lower side, but the present invention is not limited to this, and the peripheral wall 32 may be configured to be inclined inward in the radial direction toward the lower side. It may be configured to be inclined outward in the radial direction toward. The peripheral wall 32 has a star-shaped cross section. However, the shape of the peripheral wall 32 is not limited to this, and may be, for example, a regular polygonal shape as shown in FIGS. 3 to 4, or a polygonal shape other than a star shape or a regular polygonal shape (triangular shape, quadrangular shape). It may be circular, elliptical or other shape. Further, the bulging portion 30 is configured to extend over the entire circumference in the present embodiment, but is not limited to this, and a plurality of bulging portions 30 are provided side by side at intervals equal to or not equal to the circumferential direction. It may be composed of parts. In addition, in FIGS. 3 to 4, the elements corresponding to the elements shown in FIGS. 1 to 2 are designated by the same reference numerals.

By providing the bulging portion 30, the gap (ventilation path) 23 formed between the inner surface of the outer opening portion 11 and the outer surface of the lower cylinder 21d in the inner opening portion 21 is formed between the inner surface of the bulging portion 30 and the accommodating portion. It is supposed to reach between the outer surface of 22 and. Therefore, the airway of the outside air can be surely secured at the connecting portion between the outer opening portion 11 and the shoulder portion 12 where the structure is likely to be blocked. Further, by securing the airway at the connecting portion between the outer mouth portion 11 and the shoulder portion 12 in this way, it is possible to satisfactorily secure the airway downward from the airway.

The mouth portion 33 composed of the outer mouth portion 11 and the inner mouth portion 21 arranged inside the outer mouth portion 11 is provided with an outside air introduction port 14 communicating between the outer layer body 10 and the inner layer body 20. ing.

The double container 1 having such a configuration can be configured as a squeeze container by attaching a pouring cap to the outer port portion 11. In this case, as the injection cap, for example, a check valve for outside air that allows the introduction of outside air into the outside air introduction port 14 and prevents the outflow of outside air from the outside air introduction port 14 to the outside, and injection of the content liquid. It is possible to use a structure provided with a check valve for a content liquid that allows outflow and prevents the backflow of outside air into the inside of the accommodating portion 22.

In the double container 1 configured as a squeeze container, when the body 13 of the outer layer body 10 is squeezed (squeezed), the accommodating portion 22 is reduced in volume and deformed, and the content liquid is pushed out from the pouring cap and poured to the outside. Is issued. When the squeeze is released after the content liquid is poured out, the body portion 13 is restored to its original shape, and the accommodating portion 22 of the inner layer body 20 is peeled off from the inner surface of the outer layer body 10 and the outer layer is separated from the outside air introduction port 14. Outside air is introduced between the body 10 and the inner layer body 20, and only the body portion 13 is restored to its original shape while the accommodating portion 22 is reduced in volume and deformed. As a result, the content liquid contained in the accommodating portion 22 can be poured out without being replaced with the outside air, so that the contact of the outside air with the content liquid contained in the accommodating portion 22 can be reduced to prevent deterioration and deterioration thereof. It can be suppressed.

Here, in the double container 1 of the present embodiment, since a bulging portion 30 formed by projecting to the outside of the container is provided at the connecting portion between the outer opening portion 11 and the shoulder portion 12, outside air is introduced. The airway of the outside air is provided so that the outside air introduced from the mouth 14 reaches between the body 13 and the housing 22 through the gap 23 reaching from the outside air introduction port 14 between the bulging portion 30 and the housing portion 22. It can be surely secured.

Further, in the present embodiment, since the ridge 24 extending in the vertical direction is provided so as to extend from the outer port portion 11 to the bulging portion 30, the bulging portion 30 and the accommodating portion 22 are provided from the outside air introduction port 14. Since the gap 23 reaching between the two can be more reliably formed, the airway at the connecting portion between the outer opening portion 11 and the shoulder portion 12 can be more reliably secured.

Further, in the present embodiment, since a plurality of ribs 25 extending in the vertical direction are provided side by side on the shoulder portion 12 at intervals in the circumferential direction, each rib 25 in the shoulder portion 12 is provided. Since the accommodating portion 22 can be separated from the inner surface of the outer layer body 10 and then reattached to the inner surface of the outer layer body 10, the airway at the shoulder portion 12 can be more reliably secured.

As shown in FIG. 5, in the preform assembly 40, the inner preform 60 made of synthetic resin for forming the inner layer 20 is inside the outer preform 50 made of synthetic resin for forming the outer layer 10. It has a double structure that incorporates.

The outer preform 50 is formed into a predetermined shape corresponding to the outer layer body 10 by injection molding the same synthetic resin material as the outer layer body 10 using a mold. In the present embodiment, the outer preform 50 is made of polyethylene terephthalate like the outer layer 10.

The outer preform 50 has an outer mouth portion 51 having the same shape as the outer mouth portion 11 of the outer layer body 10. That is, the outer opening 51 is formed in a cylindrical shape, and male threads 51a are integrally provided on the outer peripheral surface thereof, and each of them is formed in an elongated hole shape extending in the circumferential direction and penetrates the outer opening 51 in the radial direction. The outside air introduction port 52 is provided symmetrically on both sides of the outer port portion 51 with the central axis O in between. Further, at the lower end of the outer opening portion 51, a substantially test tubular extending portion 53 having a hemispherical bottom is integrally provided. The thickness of the stretched portion 53 is thicker than that of the outer opening portion 51. The stretched portion 53 has a thickness changing portion 53a whose thickness gradually increases downward, and the thickness changing portion 53a is connected to the lower end of the outer opening portion 51 and connects the upper end of the stretched portion 53. It is configured. The thickness changing portion 53a may be provided at a portion other than the upper end of the stretching portion 53. A flange-shaped neck ring 51b is integrally provided on the outer opening portion 51.

The inner preform 60 is formed into a predetermined shape corresponding to the inner layer 20 by injection molding the same synthetic resin material as the inner layer 20 using a mold. In the present embodiment, the inner preform 60 is made of polyethylene terephthalate like the inner layer 20.

The inner preform 60 has an inner mouth portion 61 having the same shape as the inner mouth portion 21 of the inner layer body 20. That is, the inner opening portion 61 has a stepped cylindrical shape, and is arranged coaxially with the outer opening portion 51 inside the outer opening portion 51. The inner opening 61 includes an annular flange 61a placed on the upper end of the outer opening 51, a cylindrical upper cylinder 61b that hangs down from the inner peripheral edge of the flange 61a and is in contact with the inner surface of the outer opening 51, and an upper cylinder 61b. It has a conical inclined cylinder 61c whose diameter is reduced downward from the lower end of the cylinder 61b, and a cylindrical lower cylinder 61d hanging from the lower end of the inclined cylinder 61c. By providing the inclined cylinder 61c, a gap (vent) 62 is created between the inner surface of the portion of the outer preform 50 extending from the outer mouth portion 51 to the extension portion 53 (thickness change portion 53a) and the outer surface of the inner preform 60. It is formed. The outer peripheral surface of the upper cylinder 61b comes into contact with the inner peripheral surface of the outer opening portion 51 over the entire circumference, so that the upper end portion of the gap 62 is closed to the outside. When the flange 61a comes into contact with the upper end of the outer opening 51, the inner opening 61 is positioned in the vertical direction with respect to the outer opening 51. At the lower end of the inner opening portion 61, a substantially test tubular extending portion 63 having a hemispherical bottom portion is integrally provided. The outer diameter of the stretched portion 63 is smaller than the outer diameter of the inner opening portion 61. The gap 62 reaches between the outer surface of the lower portion of the stretched portion 63 and the inner surface of the lower portion of the stretched portion 53, and when the inner preform 60 is incorporated into the outer preform 50, the gap 62 reaches the outer surface of the stretched portion 63. The inner surface of the stretched portion 53 is not scratched.

On the outer surface of the inner preform 60, a plurality of ridges 64 corresponding to the plurality of ridges 24 are provided. The plurality of ridges 64 project radially outward from the outer surface of the inner preform 60 and extend in the vertical direction so as to correspond to a range extending from the outer opening portion 51 to the extending portion 53 in the outer preform. Here, "extending" to correspond to the range extending from the outer mouth portion 51 to the extending portion 53 means extending "to face" the range extending from the outer opening portion 51 to the extending portion 53. doing. Each ridge 64 extends from a height position corresponding to the outside air introduction port 52 to a position beyond the neck ring 51b and reaching a height corresponding to the extension portion 53. It is preferable that the lower end of each of the ridges 64 extends at least to a height corresponding to the connection portion between the outer opening portion 51 and the extension portion 53. The lower end of each of the ridges 64 may be located below the height corresponding to the connecting portion between the outer opening portion 51 and the extending portion 53, and in the present embodiment, the height corresponding to the thickness changing portion 53a. Is located in. At the lower end of each of the ridges 64, the height of protrusion of the inner preform 60 from the outer surface gradually decreases downward. The plurality of ridges 64 have basically the same shape as the plurality of ridges 24 of the inner layer body 20, but the portion extending to the stretched portion 63 is not stretched outward in the radial direction and is along the stretched portion 63. The difference is that it extends downward.

The mouth portion 41 composed of the outer mouth portion 51 and the inner mouth portion 61 arranged inside the outer mouth portion 51 has an outside air introduction port 52 communicating between the outer preform 50 and the inner preform 60. It is provided.

The double container 1 shown in FIG. 1 can be manufactured, for example, by the following procedure (a method for manufacturing a double container according to an embodiment of the present invention).

The method for manufacturing a double container according to the present embodiment includes a preform forming step, a preform assembling step, and a blow molding step. The method for manufacturing a double container according to the present embodiment is also applicable to the case of manufacturing a double container other than the double container 1 shown in FIG.

In the preform forming step, the outer preform 50 and the inner preform 60 are individually formed by injection molding. Here, the inner preform 60 has a plurality of ridges 64.

In the preform assembly process, the inner preform 60 is arranged inside the outer preform 50, and between the inner surface of the portion of the outer preform 50 extending from the outer opening portion 51 to the extension portion 53 and the outer surface of the inner preform 60. The preform assembly 40 is provided with a gap.

In the blow molding step, the preform assembly 40 is arranged in a mold and biaxially stretched and blow molded to have an outer layer 10 corresponding to the outer preform 50 and an inner layer 20 corresponding to the inner preform 60. The double container 1 is formed. Here, by providing a recess on the inner surface of the mold, a bulging portion 30 projecting to the outside of the container is formed at the connecting portion between the outer opening portion 11 and the shoulder portion 12 in the outer layer body 10. Further, a plurality of ridges extending in the vertical direction are provided on the inner surface of the mold corresponding to the shoulder portion 12 of the double container 1, whereby a plurality of concave ribs 25 are formed on the shoulder portion 12. To do so. When forming a plurality of concave ribs 25 instead of the plurality of convex ribs 25, a plurality of recesses extending in the vertical direction are formed on the inner surface of the mold corresponding to the shoulder portion 12. It will be provided.

In the present embodiment, the preform assembly 40 having a gap 62 provided between the inner surface of the portion of the outer preform 50 extending from the outer opening portion 51 to the extending portion 53 and the outer surface of the inner preform 60 is bulged. Since blow molding is performed using a mold having an inner surface including a recess having a shape corresponding to the portion 30, a gap 23 is formed between the bulging portion 30 and the accommodating portion 22 by the air in the gap 62. The double container 1 can be stably formed.

Further, in the present embodiment, since the preform assembly 40 in which the gap 62 reaches between the outer surface of the lower portion of the stretched portion 63 and the inner surface of the lower portion of the stretched portion 53 is used, the gap 62 is formed during blow molding. By collecting the air in the lower part of the 62 in the bulging portion 30, the double container 1 in which the gap 23 is formed between the bulging portion 30 and the accommodating portion 22 can be formed more stably.

It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist thereof.

In the above embodiment, the outside air introduction ports 52 and 14 are provided in the outer port portions 51 and 11 and are through holes penetrating the outer port portions 51 and 11, but the present invention is not limited to this, and for example, the outer port It can also be configured as a gap provided between the upper ends of the portions 51 and 11 and the upper ends of the inner opening portions 61 and 21 to open the ventilation path to the outside.

In the above embodiment, the outside air introduction port 14 of the double container 1 is formed by providing the outside air introduction port 52 in advance in the preform assembly 40 blow-molded in the double container 1, but the present invention is limited to this. Instead, for example, it may be formed by post-processing after blow molding.

In the above-described embodiment, the neck rings 51b and 11b are provided, but the present invention is not limited to this, and the neck rings 51b and 11b may not be provided.

The shapes of the shoulder portion 12 and the body portion 13 can also be changed in various ways.

In the above embodiment, the double container 1 is a squeeze-type pouring container in which a pouring cap having a spout is attached to the outer port 11 and the body 13 is squeezed to pour out the content liquid. The case where the body portion 13 is not easily squeeze-deformed (elastically deformed) has a predetermined rigidity, and the pump-type dispenser is used for a container with a pump attached to the outer port portion 11. It can also be done.

In the above-described embodiment, the ridges 64 and 24 are provided, but the present invention is not limited to this, and the ridges 64 and 24 may not be provided.

In the above-described embodiment, the rib 25 is provided on the shoulder portion 12, but the present invention is not limited to this, and the rib 25 may not be provided.

In the above embodiment, the outer preform 50 and the inner preform 60 are each formed by injection molding, but the present invention is not limited to this, and an appropriate molding method such as extrusion molding or compression molding can be used.

1 Double container 10 Outer layer 11 Outer port 11a Male screw 11b Neck ring 12 Shoulder 13 Body 14 Outside air introduction port 20 Inner layer 21 Inner port 21a Flange 21b Upper cylinder 21c Inclined cylinder 21d Lower cylinder 22 Accommodation 23 Gap 24 Convex 25 Rib 30 Proud part 31 Upper wall 32 Peripheral wall 33 Mouth 40 Preform assembly 41 Mouth 50 Outer preform 51 Outer mouth 51a Male screw 51b Neck ring 52 Outside air introduction port 53 Extension 53a Thickness change part 60 Inside Preform 61 Inner mouth 61a Flange 61b Upper cylinder 61c Inclined cylinder 61d Lower cylinder 62 Gap 63 Extension 64 Convex O Center axis

Claims (6)

An outer layer body having a tubular outer mouth portion and a bottomed tubular body portion connected to the outer mouth portion via a shoulder portion,
It has a tubular inner mouth portion and an inner layer body including a volume-reducing deformable accommodating portion which is connected to the inner mouth portion and is detachably laminated on the inner surface of the shoulder portion and the body portion.
An outside air introduction port communicating between the outer layer body and the inner layer body is provided in a mouth portion composed of the outer mouth portion and the inner mouth portion arranged inside the outer mouth portion.
A double container characterized in that the outer layer body has a bulging portion formed by projecting a connecting portion between the outer opening portion and the shoulder portion to the outside of the container. The inner layer body has protrusions extending radially outward from the outer surface of the inner layer body and extending in the vertical direction so as to correspond to a range extending from the outer mouth portion to the bulging portion in the outer layer body. The double container according to claim 1. The double container according to claim 1 or 2, wherein a rib extending in the vertical direction formed by locally projecting inside or outside the container is provided on the shoulder portion of the outer layer body. It is a method of manufacturing a double container,
An outer preform having a tubular outer mouth portion and an extending portion connected to the outer opening portion, and an inner preform having a tubular inner opening portion and an extending portion connected to the inner opening portion are individually formed. Preform formation process and
The inner preform is arranged inside the outer preform, and a gap is provided between the inner surface of the portion of the outer preform that extends from the outer opening portion to the extension portion and the outer surface of the inner preform. Preform assembly process as a remodeling assembly and
A blow molding step of forming a double container having an outer layer body corresponding to the outer preform and an inner layer body corresponding to the inner preform by arranging the preform assembly in a mold and blow molding. Have and
The outer layer body has a body portion connected to the outer mouth portion via a shoulder portion.
A double container characterized in that by providing a concave portion on the inner surface of the mold, a bulging portion projecting to the outside of the container is formed at a connecting portion between the outer opening portion and the shoulder portion in the outer layer body. Production method. The inner preform projects radially outward from the outer surface of the inner preform and extends in the vertical direction so as to correspond to the range extending from the outer opening portion to the extending portion of the outer preform. The method for producing a double container according to claim 4. The method for manufacturing a double container according to claim 4 or 5, wherein a ridge or a recess extending in the vertical direction is provided on a portion of the inner surface of the mold corresponding to the shoulder portion.

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