Double container, preform assembly, and method for manufacturing double container

Abstract

To provide a double container easily separating an inner layer body from an outer layer body: to provide a preform assembly capable of forming the double container: and to provide a method for manufacturing the double container.SOLUTION: A synthetic resin double container 1 is provided with an outer layer body 2 and an inner layer body 3 laminated on the inside of the outer layer body 2 so as to be separably formed into a bottle shape with a mouth part 11, a body part 12 and a bottom part 13, by blow-molding a preform assembly 40 obtained by assembling an inner preform 42 on the inside of an outer preform 41. The outer layer body 2 has an opening part 2c facing downward. The inner layer body 3 is exposed outside from the opening part 2c in at least the center part of the bottom part 13. The preform assembly 40 for forming the double container 1 by blow-molding, and a method for manufacturing the double container 1 are disclosed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a double container, a preform assembly, and a method for manufacturing the double container. [Background technology]

[0002] A double-layered container made of synthetic resin is known, which comprises an outer layer and an inner layer detachably laminated inside the outer layer, and is formed into a bottle shape with a mouth, a body, and a bottom (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2009-518245 Summary of the Invention [Problem to be solved by the invention]

[0004] From the viewpoint of recyclability, it is desirable that the inner layer of the double container described above be easily separated from the outer layer.

[0005] The present invention has been made in consideration of such problems, and its purpose is to provide a double container in which the inner layer can be easily separated from the outer layer, a preform assembly capable of forming such a double container, and a method for manufacturing such a double container. [Means for solving the problem]

[0006] The double container of the present invention is a synthetic resin double container formed into a bottle shape with an outer layer body and an inner layer body separably stacked inside the outer layer body by blow molding a synthetic resin preform assembly in which an inner preform formed separately from the outer preform is assembled inside the outer preform, the double container being made of synthetic resin and having a mouth, a body, and a bottom, the outer layer body having an opening facing downward, and the inner layer body being exposed to the outside from the opening at least at the center of the bottom.The outer layer body has a cylindrical outer opening portion that constitutes the opening portion, and an annular neck ring is integrally formed on the outer opening portion. The inner layer body has a cylindrical inner opening portion that is disposed inside the outer opening portion and has an upper portion that protrudes above the outer opening portion. The inner opening portion has an integral flange that is supported on the upper end of the outer opening portion to position the inner opening portion in the up-down direction relative to the outer opening portion. It is characterized by the presence of

[0007] In the double container of the present invention having the above-mentioned configuration, it is preferable that the inner layer body is exposed to the outside through the opening over the entire bottom portion.

[0008] In the double container of the present invention, in the above configuration, it is preferable that the bottom portion has a ring-shaped contact surface facing downward, and the inner layer body is covered by the outer layer body around the entire periphery of the contact surface.

[0009] In the double container of the present invention having the above-mentioned configuration, it is preferable that the outer layer and the inner layer are each made of polyethylene terephthalate.

[0010] The preform assembly of the present invention comprises an outer preform made of synthetic resin and having an opening facing downward, and an inner preform made of synthetic resin, which is formed separately from the outer preform into a cylindrical shape with a bottom and is assembled inside the outer preform, and at least a part of the bottom of the inner preform is exposed to the outside through the opening. The outer preform has a cylindrical outer opening portion, and an annular neck ring is integrally provided on the outer opening portion. The inner preform is disposed inside the outer opening portion and has a cylindrical inner opening portion whose upper portion protrudes above the outer opening portion. The inner opening portion is integrally provided with a flange that is supported on an upper end of the outer opening portion to position the inner opening portion relative to the outer opening portion in the up-down direction. It is characterized by the presence of

[0011] The method for manufacturing a double container of the present invention includes the steps of: assembling an inner synthetic resin preform formed into a cylindrical shape with a bottom separately from an outer synthetic resin preform having an opening facing downward inside the outer synthetic resin preform; forming a preform assembly in which at least a part of the bottom of the inner preform is exposed to the outside through the opening; and blow molding the preform assembly. The outer preform has a cylindrical outer opening portion with an annular neck ring integrally formed on the outer opening portion, and the inner preform has a cylindrical inner opening portion that is disposed inside the outer opening portion and has an upper portion that protrudes above the outer opening portion, and the inner opening portion has a flange that is supported by the upper end of the outer opening portion to position the inner opening portion relative to the outer opening portion in the up-down direction. It is characterized by the following. [Effects of the Invention]

[0012] According to the present invention, it is possible 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 method for manufacturing the double container. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a half cross-sectional view of a double container according to an embodiment of the present invention, as viewed from the front. [Figure 2] 2 is an enlarged cross-sectional view of a portion of the bottom of the double container shown in FIG. 1. FIG. [Figure 3] FIG. 10 is a half cross-sectional view of a double container according to a modified example, as viewed from the front. [Figure 4] 1 is a half cross-sectional view of a preform assembly according to one embodiment of the present invention; [Figure 5] FIG. 10 is a half cross-sectional view of a preform assembly according to a modified example, as viewed from the front. [Figure 6] FIG. 10 is a half cross-sectional view of a double container according to another modified example, as viewed from the front. [Figure 7] FIG. 7 is an enlarged cross-sectional view of a portion of the bottom of the double container of the modified example shown in FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0015] As shown in Figure 1, a double-layered container 1 made of synthetic resin according to one embodiment of the present invention has a double structure having an outer layer 2 and an inner layer 3, and its outer shape is a bottle shape having a mouth 11, a body 12, and a bottom 13.

[0016] The bottom 13 has a downward-facing annular ground contact surface 13a, a first recess 13b that is connected to the inner peripheral edge of the ground contact surface 13a and is recessed upward relative to the ground contact surface 13a, and a second recess 13c that is connected to the inner peripheral edge of the first recess 13b and is recessed further upward than the first recess 13b.

[0017] In this specification and claims, the up and down directions refer to the up and down directions along the axis O when the double container 1 is in an upright position with the contact surface 13a in contact with the ground as shown in Figure 1.

[0018] The outer layer 2 forms the outer shell of the double container 1 and has a cylindrical outer opening 2a that forms the mouth 11. An annular neck ring 4 is integrally provided on the outer opening 2a. An outer body 2b that corresponds to the body 12 is integrally provided and connected to the lower end of the outer opening 2a. In this embodiment, the outer body 2b has a cylindrical shape centered on the axis O.

[0019] In the double container 1 of this embodiment, the outer layer 2 has an opening 2c facing downward at its lower end. Because 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.

[0020] 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 in the circumferential direction about the axis O so that its height from the ground surface 13a is constant. As a result, in the double container 1 of this embodiment, the inner layer 3 is exposed to the outside from the opening 2c over the entire bottom 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. Note that in this embodiment, the height of the opening 2c from the ground surface 13a is constant, but this height does not have to be constant.

[0021] The inner layer body 3 is separably laminated on the inside of the outer layer body 2. Separation of the inner layer body 3 from the outer layer body 2 may be separation from an adhered state, separation from a pseudo-adhered state in the case of an incompatible resin laminate, or separation from a tightly adhered state.

[0022] The inner layer 3 is disposed inside the outer opening 2a and has a cylindrical inner opening 3a whose upper portion protrudes above the outer opening 2a. A flange 3b is integrally formed with the inner opening 3a, and the flange 3b is supported on the upper end of the outer opening 2a, thereby positioning the inner opening 3a vertically relative to the outer opening 2a.

[0023] A storage section 3c, which is continuous with the opening of the mouth section 11, is integrally provided below the inner mouth section 3a. The storage section 3c is cylindrical with a bottom and has an internal storage space S in which contents can be stored. The storage section 3c is layered on the inner peripheral surface of the outer body section 2b of the outer layer body 2, and its lower end portion protrudes downward from the opening section 2c of the outer layer body 2 to form the bottom section 13. That is, as shown in Figure 2, the contact surface 13a, first recess 13b, and second recess 13c of the bottom section 13 are formed only by the lower end portion of the storage section 3c of the inner layer body 3 that protrudes downward from the opening section 2c of the outer layer body 2.

[0024] In this embodiment, both the outer layer 2 and the inner layer 3 are made of polyethylene terephthalate (PET). By using polyethylene terephthalate for the outer layer 2 and the inner layer 3, the double container 1 can be made highly transparent and strong.

[0025] The outer layer 2 may be made of polyethylene terephthalate, and the inner layer 3 may be made of polypropylene (PP). The outer layer 2 and the inner layer 3 may be made of the same or different materials, and the outer layer 2 and the inner layer 3 may be single layer or laminated.

[0026] As shown in Fig. 1, the double container 1 can be configured with a cap 30 attached to the mouth 11. In Fig. 1, the cap 30 is shown as a hinged cap attached by stoppering to the upper end portion of the inner mouth 3a that constitutes the mouth 11, but it may have another configuration, such as being attached to the upper end portion of the inner mouth 3a by screw connection.

[0027] 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 have been used up.

[0028] Even when the double container 1 stores contents including oil, for example, and the inner layer body 3 after use is soiled to the extent that it cannot be recycled due to adhesion of the contents, the clean outer layer body 2 can be easily separated from the soiled inner layer body 3, and only the outer layer body 2 can be separated and recycled.

[0029] More specifically, if necessary, the user can flatten or push the portion of the inner layer 3 exposed to the outside through the opening 2c upward toward the inside of the outer layer 2, while 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, thereby pulling the inner layer 3 upward relative to the outer layer 2 and separating the inner layer 3 from the outer layer 2.

[0030] In a conventional double container in which the bottom 13 has a laminated structure in which the entire bottom 13 is covered with the outer layer 2, the bottom 13 is thick and has an uneven shape, so that the inner layer 3 has a strong adhesion to the outer layer 2 at the center of the bottom 13, which can hinder separation of the inner layer 3 from the outer layer 2. In contrast, in the double container 1 of this embodiment, the outer layer 2 has an opening 2c facing downward, and the inner layer 3 is exposed to the outside from the opening 2c at least at the center of the bottom 13. This prevents the adhesion of the inner layer 3 to the outer layer 2 at the bottom 13 from hindering separation, and allows the inner layer 3 to be easily separated from the outer layer 2.

[0031] In particular, when the inner layer 3 is configured so that it is exposed to the outside from the opening 2c over the entire bottom 13, as in this embodiment, the adhesion force of the inner layer 3 to the outer layer 2 at the bottom 13 is further prevented from hindering separation, making it easier to separate the inner layer 3 from the outer layer 2.

[0032] As shown as a modified example in Fig. 3, the double container 1 may be configured such that, compared to the one shown in Fig. 1, the lower end portion of the storage section 3c exposed to the outside from the opening 2c of the inner layer 3 is pushed into the outer layer 2 while its outer wall portion is inverted. Even in this case, the lower end portion of the storage section 3c of the inner layer 3 at the bottom 13 is exposed downward from the opening 2c, so that the adhesion force of the inner layer 3 to the outer layer 2 at the bottom 13 is prevented from interfering with separation, and the inner layer 3 can be easily separated from the outer layer 2.

[0033] 3, the storage section 3c of the inner layer body 3 does not protrude downward from the opening 2c of the outer layer body 2, and the opening 2c forms the contact surface 13a of the bottom 13. This increases the rigidity of the contact surface 13a, allowing the double container 1 to stand upright more stably.

[0034] The double container 1 having the above-described structure can be formed by blow molding a preform assembly 40 made of synthetic resin according to one embodiment of the present invention shown in FIG.

[0035] The preform assembly 40 has an outer preform 41 and an inner preform 42 assembled inside the outer preform 41 .

[0036] The outer preform 41 corresponds to the outer layer body 2 and includes an outer opening portion 41a and a substantially cylindrical outer extending portion 41b that is integrally connected to the lower end of the outer opening portion 41a.

[0037] 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 stretched portion 41b is substantially cylindrical, and its lower end forms an opening 41c that opens downward.

[0038] 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-mentioned shape by injection molding using polyethylene terephthalate.

[0039] The inner preform 42 corresponds to the inner layer body 3 and includes an inner opening 42a and a cylindrical, bottomed inner extension 42b that is integrally connected to the lower end of the inner opening 42a. The inner opening 42a is not extended by blow molding and has the same shape as the inner opening 3a of the double container 1. It includes a flange 42c that corresponds to the flange 3b. The inner extension 42b has a cylindrical, bottomed shape whose lower end forms a hemispherical bottom 42d, and at least a portion of the bottom 42d is exposed to the outside through the opening 41c of the outer preform 41. In this embodiment, the opening 41c is located above the bottom 42d, and the entire bottom 42d protrudes downward from the opening 41c and is exposed to the outside through the opening 41c. In this embodiment, the bottom 42d is configured to protrude downward from the opening 41c, but it is also possible to configure the bottom 42d so that it does not protrude downward from the opening 41c by making the lower end of the bottom 42d coincide with the lower end of the opening 41c or by making the lower end of the bottom 42d higher than the lower end of the opening 41c.

[0040] 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-mentioned shape separately from the outer preform 41 by injection molding using polyethylene terephthalate.

[0041] Next, a method for manufacturing a double container according to one embodiment of the present invention will be described.

[0042] The method for manufacturing a double container according to this embodiment can be carried out using the preform assembly 40 having the above-described configuration.

[0043] First, the inner preform 42 having the above-described structure is assembled inside the outer preform 41 having the above-described structure to form the preform assembly 40 having the above-described structure.

[0044] Next, the preform assembly 40 is blow-molded. For example, biaxial stretch blow molding using a stretch rod can be used as the blow molding. Note that pressurized air, pressurized liquid, etc. can be used as the pressurizing medium in the blow molding. In this way, the double container 1 having the above-mentioned configuration is formed.

[0045] Thereafter, if necessary, the contents are filled into the double container 1, and then the cap 30 is attached to the opening 11 by plugging.

[0046] Thus, according to the manufacturing method of the preform assembly 40 or double container 1 of this embodiment, a double container 1 of the above configuration, in which the outer layer 2 and the inner layer 3 can be easily separated, can be easily and inexpensively manufactured through the simple process of blow molding a preform assembly 40 configured by assembling an inner preform 42 made of synthetic resin and having a cylindrical bottom with a synthetic resin outer preform 41 having a downward-facing opening 41c.

[0047] In this embodiment, the outer preform 41 and the inner preform 42 are formed from the same synthetic resin material (polyethylene terephthalate), so even if the outer preform 41 is configured with an opening 41c, during blow molding, the inner surface of the outer extension portion 41b of the outer preform 41 is pseudo-welded to the outer surface of the inner extension portion 42b of the inner preform 42, so that the outer extension portion 41b is extended together with the inner extension portion 42b, thereby forming a double container 1 of the above shape.

[0048] In cases where it is difficult to stretch the outer extension portion 41b together with the inner extension portion 42b during blow molding, such as when the outer preform 41 and the inner preform 42 are formed from different synthetic resin materials, it is preferable to use a preform assembly 40 in which the opening 41c of the outer preform 41 is located in an area adjacent to the bottom portion 42d of the inner preform 42, and the inner diameter of the opening 41c is smaller than the maximum diameter of the bottom portion 42d, as shown as a modified example in Figure 5. In this way, during blow molding, the bottom portion 42d of the inner preform 42 catches on the inner peripheral edge of the opening 41c of the outer preform 41, so that the outer extension portion 41b is stretched together with the inner extension portion 42b, and the double container 1 having the above-mentioned shape can be formed.

[0049] The position and inner diameter of the opening 41c of the outer preform 41 may be changed as appropriate depending on the materials of the outer preform 41 and the inner preform 42, the shape of the double container 1 after molding, and the like.

[0050] As shown in Figs. 6 and 7 as modified examples, the double container 1 can also be configured such that the inner layer 3 is covered by the outer layer 2 around the entire circumference of the contact surface 13a. That is, by positioning the opening 2c of the outer layer 2 near the inner peripheral edge of the contact surface 13a of the bottom 13, the inner layer 3 can be covered by the outer layer 2 around the entire circumference of the contact surface 13a. In the illustrated example, the opening 2c is circular, centered on the axis O, and the first recess 13b and second recess 13c of the bottom 13 are exposed to the outside through the opening 2c. The double container 1 of this modified example can be manufactured using, for example, a preform assembly 40 as shown in Fig. 5.

[0051] According to the configuration of this other modified example, similar to that described above, the inner layer 3 can be easily separated from the outer layer 2 by preventing the inner layer 3 from being hindered by the adhesion force of the inner layer 3 to the outer layer 2 at the bottom 13, and the contact surface 13a of the bottom 13 is formed by the outer layer 2 laminated on the inner layer 3, thereby increasing the rigidity of the contact surface 13a and allowing the double container 1 to stand upright more stably.

[0052] In addition, in the double container 1 of the above-mentioned modified example, the outer layer 2 may be configured to cover not only the ground surface 13a but also all or part of the first recess 13b, or the outer layer 2 may be configured to cover not only the ground surface 13a and the first recess 13b but also the peripheral portion of the second recess 13c excluding the central portion.

[0053] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit and scope of the present invention.

[0054] For example, in the above embodiment, the mouth 11 is configured such that the inner mouth 3a is fitted and fixed inside the outer mouth 2a, but it can also be configured such that the inner mouth 3a is fixed inside the outer mouth 2a by threading a female thread on the inner peripheral surface of the outer mouth 2a with a male thread on the outer peripheral surface of the inner mouth 3a. In this case, the preform assembly 40 is configured such that a male thread on the outer peripheral surface of the inner mouth 42a of the inner preform 42 is threadedly connected to a female thread on the inner peripheral surface of the outer mouth 41a of the outer preform 41, and this can be blow-molded to form the double container 1 of this configuration. In this case, the inner layer body 3 is positioned relative to the outer layer body 2 by the flange 3b abutting against the upper end of the outer mouth 2a.

[0055] Furthermore, by applying a release agent such as silicone between the outer layer body 2 and the inner layer body 3, the releasability of the inner layer body 3 from the outer layer body 2 can be further improved. [Explanation of symbols]

[0056] 1 double container 2 Outer body 2a External opening 2b Outer body 2c opening 3. Inner layer 3a Inner mouth 3b flange 3c Storage area 4 neck rings 11 Mouth 12 Torso 13 Bottom 13a Ground plane 13b First recess 13c Second recess 30 Cap 40 Preform assembly 41 Outer preform 41a External opening 41b Outer extension 41c opening 42 inner preform 42a Inner mouth 42b Inner extension 42c flange 42d bottom O axis S storage space

Claims

1. A synthetic resin double container is formed into a bottle shape having an outer layer body and an inner layer body separably stacked inside the outer layer body, and having a mouth, a body, and a bottom, by blow molding a synthetic resin preform assembly in which an inner preform formed separately from the outer preform is assembled inside the outer preform, The outer layer has an opening facing downward, The inner layer body is exposed to the outside through the opening at least at the center of the bottom portion, The outer layer body has a cylindrical outer opening portion that constitutes the mouth portion, and an annular neck ring is integrally provided on the outer opening portion, A double container characterized in that the inner layer body is positioned inside the outer opening portion and has a cylindrical inner opening portion whose upper portion protrudes higher than the outer opening portion, and the inner opening portion is integrally provided with a flange that is supported by the upper end of the outer opening portion to position the inner opening portion in the vertical direction relative to the outer opening portion.

2. 2. The double container according to claim 1, wherein the inner layer is exposed to the outside through the opening over the entire bottom portion.

3. the bottom portion having a downwardly facing annular ground surface; 2. The double container according to claim 1, wherein the inner layer is covered by the outer layer around the entire periphery of the contact surface.

4. The double container according to any one of claims 1 to 3, wherein the outer layer and the inner layer are each made of polyethylene terephthalate.

5. an outer preform made of synthetic resin having an opening facing downward; an inner preform made of synthetic resin, which is formed separately from the outer preform into a cylindrical shape with a bottom, and which is assembled inside the outer preform; At least a portion of a bottom of the inner preform is exposed to the outside through the opening, the outer preform has a cylindrical outer opening, and an annular neck ring is integrally provided on the outer opening; A preform assembly characterized in that the inner preform has a cylindrical inner mouth portion that is placed inside the outer mouth portion and has an upper portion that protrudes higher than the outer mouth portion, and the inner mouth portion is integrally provided with a flange that is supported by the upper end of the outer mouth portion to position the inner mouth portion in the up-down direction relative to the outer mouth portion.

6. a step of assembling an inner synthetic resin preform formed separately from the outer synthetic resin preform into a cylindrical shape with a bottom, inside an outer synthetic resin preform having an opening facing downward, to form 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, The outer preform has a cylindrical outer opening portion, and an annular neck ring is integrally provided on the outer opening portion. A method for manufacturing a double container, characterized in that the inner preform is one that has a cylindrical inner mouth portion that is placed inside the outer mouth portion and has an upper portion that protrudes higher than the outer mouth portion, and the inner mouth portion is integrally provided with a flange that is supported by the upper end of the outer mouth portion to position the inner mouth portion in the vertical direction relative to the outer mouth portion.

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