JP2023148561A - Double container, preform assembly and method for manufacturing double container - Google Patents

Abstract

The present invention provides a double container in which an inner layer can be easily separated from an outer layer, a preform assembly capable of forming the double container, and a method for manufacturing the double container.
[Solution] By blow molding a preform assembly 40 in which an inner preform 42 is assembled inside an outer preform 41, an outer layer body 2 and an inner layer body 3 separably laminated inside the outer layer body 2 are formed. A double container 1 made of synthetic resin and formed in the shape of a bottle and having a mouth 11, a body 12, and a bottom 13, the outer layer 2 has an opening 2c facing downward, and the bottom A double container 1 characterized in that the inner layer 3 is exposed to the outside from the opening 2c at least in the center of the container 13, a preform assembly 40 for forming the double container 1 by blow molding, and Method for manufacturing double container 1.
[Selection diagram] Figure 1

Description

The present invention relates to a double container, a preform assembly, and a method for manufacturing a double container.

A double container made of synthetic resin is known, which is formed into a bottle shape and includes an outer layer body and an inner layer layered separably inside the outer layer body, and has a mouth, a body, and a bottom. (For example, see Patent Document 1).

Special Publication No. 2009-518245

From the viewpoint of recyclability, the double container as described above is desirable if the inner layer can be easily separated from the outer layer.

The present invention has been made in view of such problems, and its objects are to provide a double container in which the inner layer body can be easily separated from the outer layer body, a preform assembly capable of forming the double container, and a double container. An object of the present invention is to provide a method for manufacturing a container.

The double container of the present invention can be produced by blow molding a synthetic resin preform assembly in which an inner preform formed separately from the outer preform is assembled inside an outer preform. A double container made of synthetic resin and formed in the shape of a bottle, including an inner layer separably stacked on the inside of the body, and a mouth, a body, and a bottom, the outer layer extending downwardly. The inner layer body is exposed to the outside from the opening at least in a central portion of the bottom portion.

In the double container of the present invention, in the above configuration, it is preferable that the inner layer body is exposed to the outside through the opening in the entire bottom portion.

In the double container of the present invention, in the above configuration, it is preferable that the bottom portion includes a downwardly facing annular ground plane, and that the inner layer body is covered with the outer layer body around the entire circumference of the ground plane.

In the double container of the present invention having the above structure, it is preferable that the outer layer body and the inner layer body are each made of polyethylene terephthalate.

The preform assembly of the present invention includes an outer preform made of synthetic resin having an opening facing downward, and a synthetic resin formed separately from the outer preform into a bottomed cylindrical shape and assembled inside the outer preform. and an inner preform made of resin, and at least a part of the bottom of the inner preform is exposed to the outside through the opening.

The method for manufacturing a double container of the present invention includes an inner preform made of synthetic resin formed in a cylindrical shape with a bottom, separate from the outer preform, inside an outer preform made of synthetic resin having an opening facing downward. forming a preform assembly in which at least a portion of the bottom of the inner preform is exposed to the outside through the opening, and blow molding the preform assembly. It is characterized by

According to the present invention, it is possible to provide a double container in which the inner layer can be easily separated from the outer layer, a preform assembly capable of forming the double container, and a method for manufacturing the double container.

FIG. 1 is a half-sectional view of a double container according to an embodiment of the present invention when viewed from the front. FIG. 2 is an enlarged sectional view of a portion of the bottom of the double container shown in FIG. 1; It is a half sectional view in front view of a double container concerning a modification. 1 is a half-sectional view of a preform assembly according to an embodiment of the invention. FIG. It is a half sectional view in front view of a preform assembly concerning a modification. It is a half sectional view in front view of a double container concerning another modification. 7 is an enlarged sectional view of a portion of the bottom of the modified double container shown in FIG. 6. FIG.

Hereinafter, embodiments of the present invention will be illustrated in detail with reference to the drawings.

As shown in FIG. 1, a double container 1 made of synthetic resin according to an embodiment of the present invention has a double structure having an outer layer body 2 and an inner layer body 3, and its external shape has a mouth portion. 11, a bottle shape having a body 12 and a bottom 13.

The bottom portion 13 includes an annular ground plane 13a facing downward, a first recess 13b that is continuous with the inner peripheral edge of the ground plane 13a and recessed upward with respect to the ground plane 13a, and a first recess 13b that is continuous with the inner peripheral edge of the first recess 13b. It has a second recess 13c that is recessed further upward than the first recess 13b.

In this specification and claims, the vertical direction means upward and downward directions along the axis O when the double container 1 is in an upright position with the contact surface 13a being grounded as shown in FIG. shall be taken as a thing.

The outer layer body 2 forms the outer shell of the double container 1 and has a cylindrical outer opening 2 a forming the opening 11 . An annular neck ring 4 is integrally provided on the outer opening 2a. Moreover, an outer body part 2b corresponding to the body part 12 is integrally provided at the lower end of the outer mouth part 2a. In this embodiment, the outer body portion 2b has a cylindrical shape centered on the axis O.

In the double container 1 of this embodiment, the outer layer body 2 has an opening 2c facing downward at its lower end side. Since the outer layer 2 has the opening 2c, the inner layer 3 is exposed to the outside through the opening 2c at least in the center of the bottom 13.

In this embodiment, the outer body 2b does not extend to the bottom 13, and the opening 2c is provided in a portion of the body 12 above the bottom 13. The opening 2c extends along the circumferential direction centered on the axis O so that the height from the ground plane 13a is constant. As a result, in the double container 1 of this embodiment, the inner layer body 3 is exposed to the outside through the opening 2c in the entire bottom portion 13. That is, in the double container 1 of this embodiment, the outer layer 2 does not reach the bottom 13, and the bottom 13 is composed only of the inner layer 3. In this embodiment, the height of the opening 2c from the ground plane 13a is constant, but the height does not have to be constant.

The inner layer body 3 is separably laminated inside the outer layer body 2. The separation of the inner layer 3 from the outer layer 2 may be any of separation from an adhesive state, separation from a pseudo-adhesion state in the case of an incompatible resin laminate, or separation from a close contact state.

The inner layer body 3 has a cylindrical inner opening 3a that is disposed inside the outer opening 2a and has an upper portion projecting upward from the outer opening 2a. A flange 3b is integrally provided on the inner opening 3a, and by supporting the flange 3b on the upper end of the outer opening 2a, the inner opening 3a is positioned in the vertical direction with respect to the outer opening 2a. .

A storage portion 3c connected to the opening of the mouth portion 11 is integrally provided below the inner mouth portion 3a. The storage portion 3c has a cylindrical shape with a bottom, and the contents can be stored in the storage space S therein. The storage portion 3c is laminated on the inner circumferential surface of the outer trunk portion 2b of the outer layer body 2, and its lower end portion protrudes downward from the opening portion 2c of the outer layer body 2 to form a bottom portion 13. That is, as shown in FIG. 2, the ground plane 13a, the first recess 13b, and the second recess 13c of the bottom 13 are the lower end portions of the storage section 3c of the inner layer 3 that protrude downward from the opening 2c of the outer layer 2. It consists only of

In this embodiment, both the outer layer body 2 and the inner layer body 3 are made of polyethylene terephthalate (PET). By making the outer layer 2 and the inner layer 3 made of polyethylene terephthalate, the double container 1 can have high transparency and high strength.

Note that the outer layer 2 may be made of polyethylene terephthalate, and the inner layer 3 may be made of polypropylene (PP). Further, the outer layer 2 and the inner layer 3 may be made of the same material or different materials, and the outer layer 2 and the inner layer 3 may be a single layer or a laminate.

As shown in FIG. 1, the double container 1 can have a structure in which a cap 30 is attached to the opening 11. In FIG. 1, the cap 30 is shown as a hinged cap attached to the upper end portion of the inner mouth portion 3a constituting the mouth portion 11 by plugging. It is also possible to use other configurations, such as one that is attached to the camera.

In the double container 1 having the above structure, the inner layer 3 can be easily separated from the outer layer 2 when the contents are used up.

When the double container 1 stores contents containing oil, for example, even if the inner layer 3 after use is dirty to the extent that it cannot be recycled due to adhesion of the contents, the outer layer is clean. 2 from the dirty inner layer body 3, it becomes possible to separate and recycle only the outer layer body 2.

More specifically, the user may flatten the portion of the inner layer 3 that is exposed to the outside through the opening 2c or push it upward into the outer layer 2 as necessary. At the same time, by grasping the inner opening 3a or the cap 30 attached to the inner opening 3a and pulling it upward relative to the outer layer 2, the inner layer 3 is pulled upward relative to the outer layer 2, and the inner layer is removed. 3 can be separated from the outer layer body 2.

Here, in a conventional double container where the bottom part 13 has a laminated structure in which the inner layer body 3 is covered with the outer layer body 2, the bottom part 13 is thick and has an uneven shape. The adhesion force of the inner layer body 3 to the outer layer body 2 is large in the central portion, which may become an impediment to separating the inner layer body 3 from the outer layer body 2. In contrast, in the double container 1 of this embodiment, the outer layer body 2 has an opening 2c facing downward, and the inner layer body 3 is exposed to the outside from the opening 2c at least in the center of the bottom 13. Therefore, it is possible to easily separate the inner layer body 3 from the outer layer body 2 without inhibiting the separation due to the adhesion force of the inner layer body 3 to the outer layer body 2 at the bottom portion 13.

In particular, when the inner layer body 3 is exposed to the outside through the opening 2c in the entire bottom portion 13 as in this embodiment, the inner layer body 3 is separated from the outer layer body 2 by the adhesion force at the bottom portion 13. The inner layer body 3 can be more easily separated from the outer layer body 2 by further suppressing the inhibition of the inner layer body 3.

As shown in FIG. 3 as a modification, the double container 1 is different from the one shown in FIG. It can also be configured such that it is inverted and pushed inside the outer layer body 2. In this case as well, in the bottom part 13, the lower end portion of the housing part 3c of the inner layer body 3 is exposed downward from the opening 2c, so that separation of the inner layer body 3 and the outer layer body 2 is inhibited by the adhesion force at the bottom part 13. It is possible to easily separate the inner layer body 3 from the outer layer body 2 while suppressing the possibility that the inner layer body 3 will be damaged.

In addition, in the configuration of the modified example shown in FIG. ing. Thereby, the rigidity of the ground plane 13a is increased, and the double container 1 can be more stably erected.

The double container 1 having the above configuration can be formed by blow molding a synthetic resin preform assembly 40 according to an embodiment of the present invention shown in FIG.

The preform assembly 40 includes an outer preform 41 and an inner preform 42 assembled inside the outer preform 41.

The outer preform 41 corresponds to the outer layer body 2, and includes an outer opening 41a and a substantially cylindrical outer extending portion 41b integrally connected to the lower end of the outer opening 41a.

The outer opening 41a is a portion that is not stretched by blow molding, and has the same shape as the outer opening 2a of the double container 1. The outer extension portion 41b has a substantially cylindrical shape, and the lower end thereof is an opening portion 41c that opens downward.

The outer preform 41 is made of the same synthetic resin as the outer layer body 2, that is, polyethylene terephthalate, and is formed into the above shape by injection molding using polyethylene terephthalate.

The inner preform 42 corresponds to the inner layer body 3, and includes an inner opening 42a and a bottomed cylindrical inner extension part 42b integrally connected to the lower end of the inner opening 42a. The inner opening 42a is a portion that is not stretched by blow molding, has the same shape as the inner opening 3a of the double container 1, and is provided with a flange 42c corresponding to the flange 3b. The inner extension portion 42b has a bottomed cylindrical shape with a hemispherical bottom portion 42d at the lower end, and at least a portion of the bottom portion 42d is exposed to the outside from the opening portion 41c of the outer preform 41. In this embodiment, the opening 41c is arranged above the bottom 42d, and the entire bottom 42d protrudes downward from the opening 41c and is exposed to the outside from the opening 41c. In this embodiment, the bottom portion 42d is configured to protrude downward from the opening portion 41c, but the lower end of the bottom portion 42d may be aligned with the lower end of the opening portion 41c, or the lower end of the bottom portion 42d may be lower than the lower end of the opening portion 41c. It is also possible to configure the bottom portion 42d to be positioned upward so that the bottom portion 42d does not protrude downward from the opening portion 41c.

The inner preform 42 is made of the same synthetic resin as the inner layer body 3, that is, polyethylene terephthalate, and is formed into the above shape by injection molding using polyethylene terephthalate, separately from the outer preform 41.

Next, a method for manufacturing a double container according to an embodiment of the present invention will be described.

The method for manufacturing a double container according to this embodiment can be performed using the preform assembly 40 having the above configuration.

First, the inner preform 42 having the above structure is assembled inside the outer preform 41 having the above structure to form the preform assembly 40 having the above structure.

Next, the preform assembly 40 is blow molded. As the blow molding, for example, biaxial stretch blow molding using a stretching rod can be employed. Note that pressurized air, pressurized liquid, etc. can be used as the pressurizing medium in blow molding. In this way, the double container 1 having the above structure is formed.

Thereafter, if necessary, after filling the inside of the double container 1 with contents, the cap 30 is attached to the mouth portion 11 by plugging.

As described above, according to the method for manufacturing the preform assembly 40 or the double container 1 according to the present embodiment, a bottomed cylindrical synthetic The double container 1 having the above structure in which the outer layer body 2 and the inner layer body 3 can be easily separated is obtained by a simple process of blow molding a preform assembly 40 having a structure in which an inner preform 42 made of resin is assembled. , can be manufactured easily and inexpensively.

In this embodiment, the outer preform 41 and the inner preform 42 are made of the same synthetic resin material (polyethylene terephthalate), so even if the outer preform 41 is provided with the opening 41c, the blower During molding, the inner surface of the outer stretched portion 41b of the outer preform 41 is pseudo-welded to the outer surface of the inner stretched portion 42b of the inner preform 42, so that the outer stretched portion 41b is stretched together with the inner stretched portion 42b. , a double container 1 having the above shape can be formed.

If the outer preform 41 and the inner preform 42 are made of different synthetic resin materials, and the outer stretched part 41b is difficult to stretch together with the inner stretched part 42b during blow molding, the shape shown in FIG. As shown as an example, the preform assembly is configured such that the opening 41c of the outer preform 41 is arranged in a range adjacent to the bottom 42d of the inner preform 42, and the inner diameter of the opening 41c is less than the maximum diameter of the bottom 42d. It is preferable to use 40. As a result, during blow molding, the bottom portion 42d of the inner preform 42 is caught on the inner peripheral edge of the opening 41c of the outer preform 41, so that the outer stretched portion 41b is stretched together with the inner stretched portion 42b, A double container 1 having the above shape can be formed.

The position and inner diameter of the opening 41c of the outer preform 41 may be changed as appropriate depending on the material of the outer preform 41 or the inner preform 42, the shape of the double container 1 after molding, and the like.

As shown in FIGS. 6 and 7 as a modification, the double container 1 may have a structure in which the inner layer 3 is covered with the outer layer 2 over the entire circumference of the ground plane 13a. That is, by arranging the opening 2c of the outer layer 2 near the inner peripheral edge of the ground plane 13a of the bottom portion 13, the inner layer 3 is covered with the outer layer 2 around the entire circumference of the ground plane 13a. Can be done. In the illustrated case, the opening 2c has a circular shape centered on the axis O, and the first recess 13b and the second recess 13c of the bottom 13 are exposed to the outside from the opening 2c. This modified double container 1 can be manufactured using a preform assembly 40 as shown in FIG. 5, for example.

According to the structure of such another modification, similarly to the above-mentioned one, separation is suppressed from being inhibited by the adhesion force of the inner layer body 3 to the outer layer body 2 at the bottom part 13, and the inner layer body 3 can be separated. It can be easily separated from the outer layer body 2, and the ground plane 13a of the bottom part 13 is constituted by the outer layer body 2 laminated on the inner layer body 3, thereby increasing the rigidity of the ground plane 13a. The container 1 can be more stably erected.

In addition, in the double container 1 of the above-mentioned modification, the structure may be such that in addition to the ground plane 13a, all or part of the first recess 13b is covered by the outer layer body 2. The second recess 13c may have a structure in which the outer layer 2 covers the peripheral edge of the second recess 13c except for the center thereof.

The present invention is not limited to the embodiments described above, and can be modified in various ways without departing from the gist thereof.

For example, in the embodiment described above, the opening 11 has a structure in which the inner opening 3a is fitted and fixed inside the outer opening 2a, but a female thread provided on the inner circumferential surface of the outer opening 2a The inner opening 3a can be fixed inside the outer opening 2a by screwing the inner opening 3a to a male screw provided on the outer peripheral surface of the inner opening 3a. In this case, as the preform assembly 40, a male thread provided on the outer circumferential surface of the inner opening 42a of the inner preform 42 is screwed to a female thread provided on the inner circumferential surface of the outer opening 41a of the outer preform 41. The double container 1 having the above structure can be formed by blow molding the same structure. Also in this case, the inner layer body 3 is positioned relative to the outer layer body 2 by the flange 3b coming into contact with the upper end of the outer opening portion 2a.

Furthermore, by applying a release agent such as silicone between the outer layer 2 and the inner layer 3, the releasability of the inner layer 3 from the outer layer 2 can be further improved.

1 Double container 2 Outer layer 2a Outer mouth 2b Outer body 2c Opening 3 Inner layer 3a Inner mouth 3b Flange 3c Storage part 4 Neck ring 11 Mouth 12 Body 13 Bottom 13a Ground plane 13b First recess 13c 2 recess 30 Cap 40 Preform assembly 41 Outer preform 41a Outer opening 41b Outer extension 41c Opening 42 Inner preform 42a Inner opening 42b Inner extension 42c Flange 42d Bottom O Axis S Storage space

Claims (6)

By blow molding a synthetic resin preform assembly in which an inner preform formed separately from the outer preform is assembled inside an outer preform, the outer layer body and the inner side of the outer layer body are separably laminated. A double container made of synthetic resin and formed in the shape of a bottle and having a mouth, a body, and a bottom,
the outer layer body has an opening facing downward;
A double container, wherein the inner layer body is exposed to the outside through the opening at least in the center of the bottom. The double container according to claim 1, wherein the inner layer body is exposed to the outside from the opening in the entire bottom portion. The bottom portion includes a downwardly facing annular ground plane,
The double container according to claim 1, wherein the inner layer body is covered with the outer layer body around the entire circumference of the ground plane. The double container according to any one of claims 1 to 3, wherein the outer layer body and the inner layer body are each made of polyethylene terephthalate. an outer preform made of synthetic resin having an opening facing downward;
An inner preform made of synthetic resin is formed separately from the outer preform into a cylindrical shape with a bottom, and is assembled inside the outer preform,
A preform assembly, wherein at least a portion of the bottom of the inner preform is exposed to the outside through the opening. Separately from the outer preform, an inner preform made of synthetic resin formed into a cylindrical shape with a bottom is assembled inside an outer preform made of synthetic resin having an opening facing downward, and the bottom of the inner preform is assembled. forming a preform assembly in which at least a portion of the preform assembly is exposed to the outside through the opening;
A method for manufacturing a double container, comprising the step of blow molding the preform assembly.