Composite container, blow molding mold, and method for manufacturing composite container

Abstract

To provide a composite container, a blow forming die and a method of manufacturing the composite container, capable of suppressing the yield of composite containers from lowering.SOLUTION: A composite container 10A comprises: a container body 10 that has a mouth 11, a neck 13, a belly 20 and a bottom 30; and a plastic member 40 that is provided in close contact with an outer side of the container body 10. In the neck 13, a radially inwardly concaved recess 15 is formed. The plastic member 40 extends into the recess 15.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to composite containers, blow molding molds, and methods for manufacturing composite containers. [Background technology]

[0002] 2. Description of the Related Art Recently, bottles made of plastic have become common for containing liquid contents such as food and drink, and such plastic bottles contain liquid contents.

[0003] Such plastic bottles for containing liquid contents are manufactured by inserting a preform into a mold and subjecting it to biaxial stretch blow molding.

[0004] Conventional biaxial stretch blow molding processes use preforms containing single-layer materials, multilayer materials, or blended materials, such as PET or PP, to form container shapes. However, conventional biaxial stretch blow molding processes generally simply mold the preforms into container shapes. Therefore, when imparting various functions or properties (such as barrier properties or heat retention) to a container, the means available are limited, such as changing the materials constituting the preform. In particular, it is difficult to impart different functions or properties to different parts of the container (such as the body or bottom).

[0005] In response to this, the present applicant has proposed in Patent Document 1 a composite container that can be endowed with various functions and properties. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-128858

[0007] On the other hand, when producing such a composite container, it is required to suppress a decrease in the yield of the composite container. Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in consideration of these points, and aims to provide a composite container, a blow molding mold, and a method for manufacturing a composite container that can suppress a decrease in the yield of composite containers. [Means for solving the problem]

[0009] A composite container according to one embodiment comprises a container body having a mouth, a neck, a body, and a bottom, and a plastic member attached in close contact with the outside of the container body, with a recess formed in the neck that is recessed radially inward, and the plastic member fitting into the recess.

[0010] In the composite container according to one embodiment, the recess may be formed around the entire circumference of the neck portion.

[0011] In the composite container according to one embodiment, a plurality of the recesses may be formed along the circumferential direction.

[0012] In the composite container according to one embodiment, a plurality of the recesses may be formed along the up-down direction.

[0013] In the composite container according to one embodiment, the recess may have a depth of 0.2 mm or more and 0.8 mm or less.

[0014] A blow molding mold according to one embodiment is a blow molding mold for producing a composite container comprising a container body having a mouth, a neck, a body, and a bottom, and a plastic member attached in close contact with the outside of the container body, and a convex portion that protrudes radially inward is formed at a position corresponding to the neck of the container body.

[0015] In the blow molding die according to one embodiment, the convex portion may be formed over the entire periphery of the blow molding die.

[0016] In the blow molding die according to one embodiment, the convex portion may be formed in plurality along the circumferential direction.

[0017] In the blow molding die according to one embodiment, the convex portion may be formed in plurality along the up-down direction.

[0018] In the blow molding die according to one embodiment, the height of the convex portion may be 0.2 mm or more and 0.8 mm or less.

[0019] A method for manufacturing a composite container according to one embodiment includes the steps of preparing a preform, providing a plastic member on the outside of the preform, preparing a blow molding mold having a convex portion protruding radially inward, loading the preform and the plastic member into the blow molding mold and pressing the convex portion of the blow molding mold against the plastic member, and blow molding the preform and the plastic member in the blow molding mold, thereby expanding the preform and the plastic member as a unit and producing a container body that corresponds to the preform and has a mouth, neck, body, and bottom, and a plastic member that is attached in close contact with the outside of the container body. In the step of producing the container body and the plastic member that is attached in close contact with the outside of the container body, the shape of the convex portion of the blow molding mold is transferred, thereby forming a recess that is recessed radially inward in the neck of the container body after blow molding, and the plastic member fits into the recess. [Effects of the Invention]

[0020] According to the present disclosure, it is possible to suppress a decrease in the yield of composite containers. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a partial vertical cross-sectional view showing a composite container according to one embodiment. [Figure 2] FIG. 2 is a horizontal cross-sectional view (cross-sectional view taken along line II-II in FIG. 1) showing a composite container according to one embodiment. [Figure 3] FIG. 3 is a partially enlarged view showing a composite container according to one embodiment (an enlarged view corresponding to part III in FIG. 1). [Figure 4] FIG. 4 is a partial vertical cross-sectional view showing a composite preform according to one embodiment. [Figure 5] FIG. 5 is a horizontal cross-sectional view (cross-sectional view taken along line VV in FIG. 4) showing a composite preform according to one embodiment. [Figure 6] 6(a) to 6(d) are perspective views showing various plastic members. [Figure 7] 7(a)-(e) are schematic diagrams showing a method for manufacturing a composite container using a blow molding die according to one embodiment. [Figure 8] FIG. 8 is a schematic diagram showing a method for manufacturing a composite container using a blow molding die according to one embodiment. [Figure 9] 9(a) and 9(b) are schematic views (enlarged views corresponding to part IX in FIG. 8) showing a method for producing a composite container using a blow molding die according to one embodiment. [Figure 10] 10(a) and 10(b) are schematic diagrams showing a method for manufacturing a composite container using a blow molding die according to one embodiment. [Figure 11] FIG. 11 is a partially enlarged view showing an enlarged neck portion of a modified composite container according to one embodiment. [Figure 12] FIG. 12 is a horizontal cross-sectional view (cross-sectional view taken along line XII-XII in FIG. 11) showing a modified example of the composite container according to one embodiment. [Figure 13] FIG. 13 is a partially enlarged view showing an enlarged neck portion of another modified example of the composite container according to the embodiment. [Figure 14] FIG. 14 is an enlarged cross-sectional view showing the neck portion and the blow molding die of another modified example of the composite container according to the embodiment, and corresponds to FIG. 9(b). DETAILED DESCRIPTION OF THE INVENTION

[0022] An embodiment will now be described with reference to the drawings. FIGS. 1 to 10 are diagrams illustrating one embodiment. The following figures are schematic illustrations. Therefore, the size and shape of each part are appropriately exaggerated for ease of understanding. Furthermore, appropriate modifications can be made without departing from the technical concept. In the following figures, identical parts are denoted by the same reference numerals, and some detailed descriptions may be omitted. Furthermore, the numerical values, such as dimensions, and material names of each component described in this specification are merely examples of an embodiment, and are not limited to these and may be selected and used as appropriate. In this specification, terms specifying shapes or geometric conditions, such as parallel, orthogonal, and perpendicular, are intended to include substantially the same state in addition to their strict meanings.

[0023] Composite container structure First, an outline of the composite container according to this embodiment will be described with reference to FIGS. In this specification, "upper" and "lower" refer to the upper and lower sides, respectively, of the composite container 10A when it is held upright (FIG. 1).

[0024] The composite container 10A shown in Figures 1 and 2 is obtained by performing biaxial stretch blow molding on a composite preform 70 (see Figures 4 and 5) including a preform 10a and a plastic member 40a using a blow molding mold 50, as described below, to expand the preform 10a and the plastic member 40a of the composite preform 70 as a single unit.

[0025] Such a composite container 10A comprises a container body 10 made of a plastic material located inside, and a plastic member 40 provided on the outside of the container body 10 in close contact therewith.

[0026] Of these, the container body 10 comprises a mouth portion 11, a neck portion 13 provided below the mouth portion 11, a shoulder portion 12 provided below the neck portion 13, a body portion 20 provided below the shoulder portion 12, and a bottom portion 30 provided below the body portion 20.

[0027] On the other hand, the plastic member 40 is tightly attached to the outer surface of the container body 10 in a thinly stretched state, and is attached in a state in which it does not easily move or rotate relative to the container body 10.

[0028] Next, the container body 10 will be described in detail with reference to Figures 1 to 3. The container body 10 has the mouth portion 11, the neck portion 13, the shoulder portion 12, the body portion 20, and the bottom portion 30, as described above.

[0029] Of these, the mouth portion 11 has a threaded portion 14 onto which a cap (not shown) is screwed, a cap 16 provided below the threaded portion 14, and a flange portion 17 provided below the cap 16. The shape of the mouth portion 11 may be any conventionally known shape. The container body 10 is filled with contents such as a liquid content, and a cap (not shown) is screwed onto the mouth portion 11 to produce a composite container containing the contents.

[0030] Neck 13 is located between flange 17 and shoulder 12, and has a generally cylindrical shape with a generally uniform diameter except for recess 15, which will be described later. Shoulder 12 is located between neck 13 and body 20, and has a shape whose diameter gradually increases from the neck 13 side toward the body 20 side (a shape whose area gradually increases in horizontal cross section).

[0031] Furthermore, a recess 15 recessed radially inward is formed in the neck portion 13. In this embodiment, the recess 15 is formed so as to straddle the neck portion 13 and the shoulder portion 12. That is, the recess 15 is formed in a region including the end of the neck portion 13 on the shoulder portion 12 side and the end of the shoulder portion 12 on the neck portion 13 side. Note that the recess 15 may be formed so that the entirety is located within the neck portion 13, without straddling the neck portion 13 and the shoulder portion 12.

[0032] Such a recess 15 is formed over the entire circumference of the neck portion 13. In this case, as will be described later, during blow molding, the plastic member 40a of the composite preform 70 described later is pressed against the protrusion 55 of the blow molding die 50 over the entire circumference. This makes it possible to effectively prevent the plastic member 40a from moving relative to the body portion 20a of the preform 10a during blow molding.

[0033] 3, the recess 15 includes a recess upper surface 151 and a recess lower surface 152. The deepest part P1 of the recess 15 is located between the recess upper surface 151 and the recess lower surface 152. The shape of the recess 15 is a shape transferred from the inner surface shape of the blow molding die 50 that molds the composite container 10A.

[0034] The depth D (radial distance, see FIG. 3) of the recess 15 is preferably 0.2 mm or more and 0.8 mm or less. The depth D of the recess 15 refers to the radial distance from the inner surface 13a of the neck portion 13 other than the recess 15 to the deepest part P1 of the recess 15. As described above, the shape of the recess 15 is a shape transferred from the inner surface shape of the blow molding die 50 that molds the composite container 10A. That is, the depth D of the recess 15 corresponds to the height H (see FIG. 9(a)) of the protrusions 55 of the blow molding die 50, which will be described later. When the depth D of the recess 15 is increased, the height H of the protrusions 55 increases. Therefore, by making the depth D of the recess 15 0.2 mm or more, the height H of the protrusion 55 becomes a predetermined height or more, and as will be described later, when the protrusion 55 of the blow molding die 50 is pressed against the plastic member 40a of the composite preform 70, the plastic member 40a can be firmly sandwiched between the protrusion 55 and the preform 10a. In addition, by making the depth D of the recess 15 0.8 mm or less, good shaping properties can be achieved during blow molding.

[0035] Furthermore, it is preferable that the vertical distance L1 (see FIG. 3) from the deepest part P1 of the recess 15 to the lower surface of the flange part 17 is 1.5 mm or more and 5 mm or less. In this case, in the blow molding die 50 described later, the vertical distance L2 (see FIG. 9(a)) from the contact surface 50d of the pair of body dies 50a, 50b to the tip end P2 of the protrusion 55 can be 1.5 mm or more and 5 mm or less.

[0036] 1 and 2, the body portion 20 has a cylindrical shape with a generally uniform diameter overall. However, this is not limited thereto, and the body portion 20 may have a polygonal cylindrical shape such as a rectangular cylindrical shape or an octagonal cylindrical shape. Alternatively, the body portion 20 may have a cylindrical shape with a non-uniform horizontal cross section from top to bottom.

[0037] This body portion 20 is formed with a first horizontal groove 25 and a second horizontal groove 26 that is shallower than the first horizontal groove 25 (see FIG. 1). The first horizontal groove 25 and the second horizontal groove 26 each extend around the entire circumferential direction of the body portion 20, and their respective up-down widths are uniform around the entire circumferential direction.

[0038] In the illustrated example, three second horizontal grooves 26, three first horizontal grooves 25, and three second horizontal grooves 26 are formed in this order in the body 20 from the shoulder 12 side toward the bottom 30 side.

[0039] In this case, the first horizontal grooves 25 and second horizontal grooves 26 formed in the body 20 are arranged symmetrically in both positional relationship and spacing with respect to the first horizontal groove 25 that is located in the center in the vertical direction among the three first horizontal grooves 25. This allows each of the first horizontal grooves 25 and each of the second horizontal grooves 26 to absorb the reduced pressure evenly when the pressure inside the container body 10 is reduced.

[0040] The first horizontal grooves 25 mainly function to absorb reduced pressure by contracting in the vertical direction when the pressure inside the container body 10 is reduced. The first horizontal grooves 25 also serve to increase the strength of the central area of ​​the body 20, which is a portion that is easily deformed.

[0041] The second horizontal grooves 26 mainly serve to increase the strength of the areas around the shoulders 12 and the bottom 30, which are relatively easily deformed parts of the body 20, and to prevent these areas from collapsing in the horizontal direction. The second horizontal grooves 26 also have the additional function of absorbing reduced pressure by contracting in the vertical direction. Note that the depth of the second horizontal grooves 26 is not too large (for example, about the same as the first horizontal grooves 25), which prevents the capacity of the container body 10 from decreasing.

[0042] The thickness of the container body 10 at the barrel 20 is not limited to this, but can be as thin as, for example, 50 μm or more and 250 μm or less. Furthermore, the weight of the container body 10 is not limited to this either, but can be 10 g or more and 20 g or less. By reducing the thickness of the container body 10 in this way, the weight of the container body 10 can be reduced.

[0043] On the other hand, the bottom 30 has a depression 31 located in the center and a grounding portion 32 provided around this depression 31. The shape of the bottom 30 is not particularly limited, and it may have any conventionally known bottom shape (for example, a petaloid bottom shape, a rounded bottom shape, etc.).

[0044] Such a container body 10 can be produced by biaxially stretching and blow molding a preform 10a (described below) produced by injection molding a synthetic resin material. The container body 10 is preferably made of a thermoplastic resin, particularly PE (polyethylene), PP (polypropylene), PET (polyethylene terephthalate), PEN (polyethylene naphthalate), or PC (polycarbonate). The container body 10 may be colored in colors such as red, blue, yellow, green, brown, black, or white, but is preferably colorless and transparent for ease of recycling. A blend of the various resins described above may also be used. Furthermore, a vapor-deposited film, such as a diamond-like carbon film or a silicon oxide thin film, may be formed on the inner surface of the container body 10 to enhance the barrier properties of the container.

[0045] The container body 10 can also be formed as a multi-layered bottle having two or more layers. That is, a preform 10a having three or more layers, for example, with an intermediate layer made of a resin having gas barrier properties (intermediate layer) such as MXD6, MXD6 + fatty acid salt, PGA (polyglycolic acid), EVOH (ethylene vinyl alcohol copolymer), or PEN (polyethylene naphthalate), may be injection molded, followed by blow molding to form a multi-layered bottle having gas barrier properties. Note that the intermediate layer may be made of a resin blend of the various resins described above.

[0046] Alternatively, a foamed preform having a foam cell diameter of 0.5 μm or more and 100 μm or less may be formed by mixing an inert gas (nitrogen gas, argon gas) with a melt of a thermoplastic resin, and then blow-molding this foamed preform to produce the container body 10. Since such a container body 10 has built-in foam cells, the light-blocking properties of the entire container body 10 can be improved.

[0047] Such a container body 10 may be a bottle having a full capacity of, for example, 100 ml to 2000 ml, or may be a large bottle having a full capacity of, for example, 10 L to 60 L.

[0048] Next, we will explain the plastic member 40. As will be described later, the plastic member 40 (40a) is provided so as to surround the outside of the preform 10a, and is obtained by being brought into close contact with the outside of the preform 10a and then being biaxially stretched and blow molded together with the preform 10a.

[0049] The plastic member 40 is attached to the outer surface of the container body 10 without being glued, and is in close contact with the container body 10 so that it does not move or rotate relative to the container body 10. This plastic member 40 is stretched thinly on the outer surface of the container body 10 and covers the container body 10. As shown in Fig. 2, the plastic member 40 is provided over the entire circumferential direction of the container body 10 so as to surround it, and has a substantially circular horizontal cross section.

[0050] In this case, the plastic member 40 is provided so as to cover the neck portion 13, shoulder portion 12, body portion 20, and bottom portion 30 of the container body 10, excluding the mouth portion 11. This allows the neck portion 13, shoulder portion 12, body portion 20, and bottom portion 30 of the container body 10 to be endowed with desired functions and properties.

[0051] The plastic member 40 may be provided on the entire area of ​​the container body 10 except for the mouth 11. For example, the plastic member 40 may be provided so as to entirely cover the neck 13, shoulder 12, body 20, and bottom 30 of the container body 10 except for the mouth 11. Furthermore, the plastic member 40 may be provided on a partial area of ​​the container body 10 except for the mouth 11, as long as it is provided on a partial area of ​​the neck 13 of the container body 10 (i.e., as long as at least a portion of the plastic member 40 is provided so as to fit into the recess 15). For example, the plastic member 40 may be provided so as to cover the neck 13, shoulder 12, body 20, and bottom 30 of the container body 10 except for the mouth 11 and the center of the bottom 30.

[0052] Because the plastic member 40 is not welded or bonded to the container body 10, it can be peeled off and removed from the container body 10. Specifically, for example, the plastic member 40 can be cut off using a blade or the like, or a cutting line (not shown) can be provided in advance on the plastic member 40 and the plastic member 40 can be peeled off along this cutting line. In this way, the plastic member 40 can be separated and removed from the container body 10.

[0053] Such a plastic member 40 may be one that does not have a shrinking action relative to the preform 10a, or may be one that has a shrinking action.

[0054] When the plastic member 40 has the ability to shrink relative to the preform 10a, the plastic member 40 is provided on the outside of the preform 10a, heated together with the preform 10a, and biaxially stretched and blow-molded to obtain the plastic member 40.

[0055] In this embodiment, the plastic member 40 fits into the recess 15 formed in the neck portion 13 of the container body 10. Here, the plastic member 40 that fits into the recess 15 is formed by pressing the plastic member 40a of the composite preform 70, which will be described later, against the convex portion 55 of the blow molding die 50, which will be described later, during blow molding, and shaping it into a shape that corresponds to the inner surface of the convex portion 55. In this way, during blow molding, the plastic member 40a of the composite preform 70 is pressed against the convex portion 55 of the blow molding die 50 that forms the recess 15, thereby making it possible to prevent the plastic member 40a from moving relative to the body portion 20a of the preform 10a.

[0056] The plastic member 40 is preferably made of a thermoplastic, non-elastic resin, such as polyethylene (PE), e.g., low-density polyethylene (LDPE), polypropylene (PP), polyethylene terephthalate (PET), or polyethylene naphthalate (PEN). Blends of these materials, multilayer structures, or partially multilayer structures may also be used. Furthermore, various additives may be added to the material of the plastic member 40 in addition to the main resin component, as long as the properties are not impaired. Furthermore, by mixing an inert gas (nitrogen gas, argon gas) with a molten thermoplastic resin, a foamed member with a foam cell diameter of 0.5 μm to 100 μm can be used, and this foamed preform can be molded to enhance light blocking properties.

[0057] The plastic member 40 may be made of a material with light barrier properties that can block invisible light such as ultraviolet rays. In this case, the light barrier properties of the composite container 10A can be improved and the liquid contained therein can be prevented from being deteriorated by ultraviolet rays or the like without using a multilayer preform or a preform containing a blend material as the preform 10a. Possible materials for this purpose include blend materials, or materials in which a light-blocking resin is added to PET, PE, or PP. Alternatively, a foamed material having a foam cell diameter of 0.5 μm to 100 μm, which is produced by mixing a molten thermoplastic resin with an inert gas (nitrogen gas, argon gas), may be used.

[0058] The plastic member 40 may be colored in red, blue, yellow, green, brown, black, white, or the like, and may be transparent or opaque.

[0059] Furthermore, the thickness of the plastic member 40 is not limited to this, but can be, for example, about 5 μm or more and 500 μm or less when attached to the container body 10.

[0060] Composite preform composition Next, the structure of the composite preform will be described with reference to FIGS.

[0061] As shown in FIGS. 4 and 5, the composite preform 70 includes a preform 10a made of a plastic material and a cylindrical plastic member 40a with a bottom provided on the outside of the preform 10a.

[0062] The preform 10a has a mouth portion 11a, a body portion 20a connected to the mouth portion 11a, and a bottom portion 30a connected to the body portion 20a. Of these, the mouth portion 11a corresponds to the mouth portion 11 of the container body 10 described above, and has substantially the same shape as the mouth portion 11. That is, the mouth portion 11a has a thread portion 14a corresponding to the thread portion 14 of the container body 10, a turnip 16a corresponding to the turnip 16, and a flange portion 17a corresponding to the flange portion 17.

[0063] The body portion 20a corresponds to the neck portion 13, shoulder portion 12, and body portion 20 of the container body 10 described above. The body portion 20a has a large diameter portion 21a on the mouth portion 11a side, a reduced diameter portion 22a provided below the large diameter portion 21a, and a small diameter portion 23a provided below the reduced diameter portion 22a.

[0064] Of these, the large diameter portion 21a is the portion of the body portion 20a with the largest outer diameter, and has a cylindrical shape with a substantially uniform outer diameter. The thickness of the large diameter portion 21a is substantially constant overall.

[0065] The reduced diameter portion 22a has a shape in which the outer diameter gradually decreases downward, and the thickness of the reduced diameter portion 22a gradually increases downward.

[0066] The small diameter portion 23a is the portion of the body portion 20a that has the smallest outer diameter, and has a cylindrical shape with a substantially uniform outer diameter. The thickness of the small diameter portion 23a is substantially constant overall.

[0067] It should be noted that body portion 20a may have a cylindrical shape with a substantially uniform diameter as a whole, without having large diameter portion 21a, reduced diameter portion 22a, and small diameter portion 23a.

[0068] The bottom portion 30a corresponds to the bottom portion 30 of the container body 10 described above, and has a substantially hemispherical shape.

[0069] The plastic member 40a is attached to the outer surface of the preform 10a without being bonded, and is in close contact with the preform 10a so as not to move or rotate relative to the preform 10a, or so as not to fall under its own weight. The plastic member 40a is provided over the entire circumferential area of ​​the preform 10a so as to surround it, and has a circular horizontal cross section.

[0070] In this case, the plastic member 40a is provided so as to cover the entire body portion 20a and the entire bottom portion 30a of the preform 10a.

[0071] Note that the plastic member 40a may be provided on a partial region of the body 20a of the preform 10a (i.e., as long as the plastic member 40a is provided so as to be pressed against a protrusion 55 of the blow molding die 50 described below), but may also be provided on a partial region other than the mouth 11a. For example, the plastic member 40a may be provided so as to cover the body 20a excluding the bottom 30.

[0072] Such a plastic member 40a may be one that does not have a shrinking action relative to the preform 10a, or may be one that has a shrinking action.

[0073] When the plastic member 40a has a shrinking property, the plastic member 40a may be one that shrinks (e.g., thermally shrinks) relative to the preform 10a when an external force (e.g., heat) is applied to it. Alternatively, the plastic member 40a may itself have shrinkability or elasticity and be capable of shrinking without the application of an external force.

[0074] In addition, if the plastic member 40a has a thermal contraction property, after the cylindrical plastic member 40a is fitted into the preform 10a, the margin formed at the lower end portion of the plastic member 40a (the end portion opposite the mouth portion 11a) may be thermally compressed.

[0075] Examples of the plastic member 40a that can be used include a direct blow tube made by direct blow molding, a sheet molded tube made by sheet molding, an extruded tube made by extrusion molding, an injection molded tube made by injection molding, and an inflation molded tube made by inflation molding, but the plastic member 40a is not limited to these, and molding methods other than those mentioned above may also be used.

[0076] The plastic member 40a may be colored in red, blue, yellow, green, brown, black, white, or the like, and may be transparent or opaque.

[0077] The thickness of the plastic member 40a is not limited to this, but may be, for example, about 0.1 mm or more and 0.5 mm or less, and may be 0.3 mm as an example.

[0078] Next, the shape of the plastic member 40a will be described.

[0079] As shown in FIG. 6(a), the plastic member 40a may have a cylindrical shape with a bottom as a whole, including a cylindrical body 41 and a bottom 42 connected to the body 41. In this case, the bottom 42 of the plastic member 40a covers the bottom 30a of the preform 10a, so that various functions and properties such as barrier properties can be imparted to the bottom 30 as well as the body 20 of the composite container 10A. The plastic member 40a may also have a cylindrical shape with no seams around its entire circumference. Examples of such a plastic member 40a include the above-mentioned direct blow tube, sheet-molded tube, and injection-molded tube.

[0080] 6(b), the plastic member 40a may have a circular tubular shape (a cylindrical shape without a bottom) as a whole, and may have a cylindrical body 41. The plastic member 40a may also have a cylindrical shape with no seams along the entire circumference. In this case, the plastic member 40a may be, for example, the above-mentioned blown tube, extruded tube, inflation tube, or sheet-molded tube.

[0081] 6(c) and 6(d), the plastic member 40a may be produced by forming a film into a cylindrical shape and bonding the ends together. In this case, the plastic member 40a may be configured in a tubular shape (cylindrical shape without a bottom) having a body 41 as shown in Fig. 6(c), or may be configured in a cylindrical shape with a bottom by bonding a bottom 42 as shown in Fig. 6(d).

[0082] Composite preform and method for manufacturing composite container Next, a method for manufacturing the composite container 10A according to this embodiment (blow molding method) will be described with reference to FIGS. 7(a)-(e), 8, 9(a)-(b), and 10(a)-(b).

[0083] First, a preform 10a made of a plastic material is prepared (see FIG. 7(a)). In this case, the preform 10a may be produced by injection molding using, for example, an injection molding machine (not shown). Alternatively, a preform that is generally used in the past may be used as the preform 10a.

[0084] Next, a plastic member 40a is provided on the outside of the preform 10a to produce a composite preform 70 having the preform 10a and the plastic member 40a attached to the outside of the preform 10a (see FIG. 7(b)). In this case, the plastic member 40a has a cylindrical shape with a bottom as a whole, and has a cylindrical body 41 and a bottom 42 connected to the body 41.

[0085] At this time, a plastic member 40a having an inner diameter equal to or slightly smaller than the outer diameter of the preform 10a may be pressed against the preform 10a to adhere to the outer surface of the preform 10a. Alternatively, as will be described later, a heat-shrinkable plastic member 40a may be provided on the outer surface of the preform 10a, and the plastic member 40a may be heated to 50°C to 100°C to cause heat shrinkage and adhere to the outer surface of the preform 10a.

[0086] In this way, by first adhering a plastic member 40a to the outside of the preform 10a to produce the composite preform 70, it becomes possible to carry out the series of steps for producing the composite preform 70 (Figures 7(a)-(b)) and the series of steps for producing the composite container 10A by blow molding (Figures 7(c)-(e), Figure 8, Figures 9(a)-(b) and Figures 10(a)-(b)) in separate locations (factories, etc.).

[0087] Next, the composite preform 70 is heated by the heating device 51 (see FIG. 7(c)). At this time, the composite preform 70 is heated uniformly in the circumferential direction by the heating device 51 while being rotated with the mouth portion 11a facing downward. The heating temperature of the preform 10a and the plastic member 40a in this heating step may be, for example, 90°C to 130°C.

[0088] Also, a blow molding die 50 for producing the composite container 10A is prepared. As will be described later, this blow molding die 50 has a convex portion 55 (see FIG. 8) that protrudes radially inward. In this embodiment, a blow molding die 50 having such a convex portion 55 formed thereon is also provided.

[0089] Then, the composite preform 70 heated by the heating device 51 is sent to the blow molding die 50 (see FIG. 7(d)).

[0090] The composite container 10A is molded using this blow molding die 50. In this case, the blow molding die 50 has a die body 52, which is a metal die or a resin die, and the die body 52 consists of a pair of mutually separated body dies 50a, 50b and a bottom die 50c (see FIG. 7(d)). The inner surface of the die body 52 has a shape corresponding to the shoulder 12, neck 13, body 20, and bottom 30 of the composite container 10A. In FIG. 7(d), the pair of body dies 50a, 50b are open to each other, and the bottom die 50c is raised upward.

[0091] Next, the preform 10a and the plastic member 40a are placed in the blow molding die 50, and a convex portion 55 (described later) of the blow molding die 50 is pressed against the plastic member 40a. At this time, the composite preform 70 is first inserted between the pair of body dies 50a, 50b of the die main body 52 in the state shown in Figure 7(d). Next, as shown in Figure 7(e), the bottom die 50c is lowered and then the pair of body dies 50a, 50b are closed, thereby forming a sealed blow molding die 50 with the pair of body dies 50a, 50b and the bottom die 50c of the die main body 52.

[0092] 8 and 9(a), the blow molding die 50 is formed with a convex portion 55 that protrudes radially inward. Specifically, a convex portion 55 that protrudes radially inward is formed on each of a pair of body dies 50a, 50b of the die main body 52. ​​The convex portion 55 is formed at a position corresponding to the neck portion 13 of the container body 10, and the shape of the convex portion 55 corresponds to the shape of the concave portion 15 of the container body 10. In FIG. 8, regions of the inner surface of the die main body 52 that correspond to the neck portion 13, shoulder portion 12, and body portion 20 of the container body 10 are indicated by corresponding symbols in imaginary lines (two-dot chain lines).

[0093] When the sealed blow molding die 50 is constructed, the plastic member 40a is pressed against the convex portion 55 of the blow molding die 50. At this time, the inner diameter of the convex portion 55 is larger than the outer diameter of the reduced diameter portion 22a of the body portion 20a of the preform 10a at any point on the convex portion 55. Therefore, the convex portion 55 does not come into contact with the preform 10a. This makes it possible to prevent the pair of body dies 50a, 50b from being unable to close.

[0094] Furthermore, as shown in FIG. 9(a), when the protrusion 55 abuts against the plastic member 40a, A space S is formed in the circumferential direction between the plastic member 40a and the inner surfaces 501 of the pair of body dies 50a, 50b at a portion of the inner surfaces 501 that is located closer to the contact surface 50d than the protrusions 55. In other words, the plastic member 40a does not come into direct contact with the pair of body dies 50a, 50b except for the protrusions 55.

[0095] Such a convex portion 55 is formed over the entire circumference of the portion of the blow molding die 50 that corresponds to the neck portion 13. As a result, when the plastic member 40a is pressed against the convex portion 55 of the blow molding die 50, the plastic member 40a is pressed against the convex portion 55 over the entire circumference. Therefore, as will be described later, it is possible to effectively prevent the plastic member 40a from moving relative to the body portion 20a of the preform 10a during blow molding.

[0096] As shown in FIG. 9(a), the height H (the amount of radial inward protrusion) of the convex portion 55 is preferably 0.2 mm or more and 0.8 mm or less. The height H of the convex portion 55 refers to the radial distance from the inner surface 501 of the pair of body molds 50a, 50b, at a portion located closer to the contact surface 50d than the convex portion 55, to the tip end P2 of the convex portion 55 (the point of the convex portion 55 located most radially inward). When the height H of the convex portion 55 is 0.2 mm or more, the plastic member 40a can be firmly sandwiched between the convex portion 55 and the preform 10a when the convex portion 55 is pressed against the plastic member 40a. When the height H of the convex portion 55 is 0.8 mm or less, good shaping properties can be achieved during blow molding.

[0097] Furthermore, the vertical distance L2 from the contact surface 50d of the pair of body dies 50a, 50b that contacts the flange portion 17a to the tip end P2 of the convex portion 55 is preferably 1.5 mm or more and 5 mm or less.

[0098] Incidentally, when the composite preform 70 is produced, a gap G may be formed in the vertical direction between the flange portion 17a of the preform 10a and the plastic member 40a. Here, by setting the vertical distance L2 from the contact surface 50d to the tip end P2 of the protrusion 55 to be 1.5 mm or more, it is possible to prevent the protrusion 55 from being disposed in the gap G when the blow molding die 50 is sealed. In other words, the protrusion 55 can be disposed so that the plastic member 40a is pressed against the protrusion 55 when the blow molding die 50 is sealed.

[0099] Furthermore, by setting the vertical distance L2 to 5 mm or less, the convex portions 55 can be pressed against a region of the plastic member 40a that is 5 mm or less from the lower surface of the flange portion 17a. Here, in the composite preform 70, the region that is 5 mm or less from the lower surface of the flange portion 17a is a region where the stretch ratio is small. By pressing the convex portions 55 against the plastic member 40a in this region where the stretch ratio is small, it is possible to prevent the convex portions 55 from interfering with the stretching of the preform 10a and the plastic member 40a when they are stretched. This makes it possible to prevent a decrease in moldability during blow molding.

[0100] When producing a composite container 10A using such a blow molding die 50, air is forced into the preform 10a, and biaxial stretch blow molding is performed on the composite preform 70, as shown in Figures 9(b) and 10(a).

[0101] As a result, the composite preform 70 is shaped into a shape corresponding to the inner surface of the blow molding die 50, and the container body 10 is obtained from the preform 10a within the blow molding die 50. During this process, the body dies 50a and 50b are heated to 30°C to 80°C, and the bottom die 50c is cooled to 5°C to 25°C. Furthermore, within the blow molding die 50, the shape of the convex portion 55 of the blow molding die 50 (mold body 52) is transferred, thereby forming a recess 15 recessed radially inward in the neck portion 13 of the container body 10 after blow molding. At this time, within the blow molding die 50, the preform 10a and the plastic member 40a of the composite preform 70 are expanded as a single unit. As a result, the preform 10a and the plastic member 40a are shaped into a shape corresponding to the inner surface of the blow molding die 50 as a single unit. As a result, the plastic member 40 after blow molding fits into the recess 15.

[0102] Here, when the preform 10a and the plastic member 40a are expanded as a unit, the plastic member 40a may move relative to the body 20a of the preform 10a as the preform 10a is stretched. That is, as the body 20a and bottom 30a (see FIG. 4) of the preform 10a are stretched, the plastic member 40a may be pulled toward the bottom 30a of the preform 10a, causing the plastic member 40a to move toward the bottom 30a relative to the body 20a. If the plastic member 40a moves relative to the body 20a in this way, it may be difficult for the plastic member 40 after blow molding to cover the desired region of the container body 10 (e.g., the neck 13 or the shoulder 12). In this case, the composite container 10A is discarded as a defective product, reducing the yield of the composite container 10A. In this case, certain areas of the container body 10 (for example, the neck portion 13 and the shoulder portion 12) may be exposed to the outside, which may make it difficult to fully impart the desired functions and characteristics to the container body 10.

[0103] In contrast, in the present embodiment, the plastic member 40a is pressed against the convex portion 55 of the blow molding die 50. As a result, the plastic member 40a is sandwiched between the convex portion 55 of the blow molding die 50 and the body portion 20a of the preform 10a. This makes it possible to prevent the plastic member 40a from moving relative to the body portion 20a of the preform 10a. As a result, it is possible to reduce the number of composite containers 10A that are discarded as defective products, and to prevent a decrease in the yield of composite containers 10A. Furthermore, the plastic member 40 can cover desired areas of the container body 10 (for example, the neck portion 13 and shoulder portion 12), making it possible to effectively impart desired functions and properties to the container body 10.

[0104] 10(b), the pair of body molds 50a, 50b and the bottom mold 50c of the mold body 52 are separated from each other, and the composite container 10A is removed from the blow molding mold 50. In this way, the composite container 10A shown in FIGS. 1 and 2 is obtained.

[0105] As described above, according to this embodiment, the neck portion 13 of the container body 10 is formed with a recess 15 recessed radially inward, and the plastic member 40 fits into the recess 15. In this case, during blow molding, the plastic member 40a is pressed against the protrusion 55 of the blow molding die 50 that forms the recess 15. This prevents the plastic member 40a from moving relative to the body portion 20a of the preform 10a. This reduces the number of composite containers 10A that are discarded as defective products, and prevents a decrease in the yield of the composite containers 10A. Furthermore, the plastic member 40 can cover desired regions of the container body 10 (for example, the neck portion 13 and shoulder portion 12), effectively imparting desired functions and properties to the container body 10.

[0106] Furthermore, according to this embodiment, the plastic member 40 can be separated and removed from the container body 10, so that the colorless and transparent container body 10 can be recycled in the same way as in the conventional case.

[0107] Furthermore, according to this embodiment, the recess 15 is formed around the entire circumference of the neck portion 13. In this case, during blow molding, the plastic member 40a is pressed against the protrusion 55 of the blow molding die 50 along the entire circumference. This makes it possible to effectively prevent the plastic member 40a from moving relative to the body portion 20a of the preform 10a during blow molding.

[0108] Furthermore, according to this embodiment, the blow molding die 50 is formed with a convex portion 55 that protrudes radially inward at a position corresponding to the neck portion 13 of the container body 10. As a result, the plastic member 40a is pressed against the convex portion 55 of the blow molding die 50 during blow molding, and it is possible to prevent the plastic member 40a from moving relative to the body portion 20a of the preform 10a during blow molding. This makes it possible to reduce the number of composite containers 10A that are discarded as defective products, and to prevent a decrease in the yield of composite containers 10A.

[0109] Furthermore, according to this embodiment, the convex portion 55 is formed around the entire circumference of the blow molding die 50. As a result, when the plastic member 40a is pressed against the convex portion 55 of the blow molding die 50, the plastic member 40a is pressed against the convex portion 55 around the entire circumference. Therefore, it is possible to effectively prevent the plastic member 40a from moving relative to the body portion 20a of the preform 10a during blow molding.

[0110] In the above embodiment, the recess 15 is formed around the entire circumference of the neck portion 13. However, this is not limiting, and as shown in Figs. 11 and 12, a plurality of recesses 15 may be formed along the circumferential direction. In this case, as shown in Fig. 12, a plurality of protrusions 55 are formed on the blow molding die 50 along the circumferential direction. In the example shown in Fig. 12, four recesses 15 (protrusions 55) are formed spaced apart from each other along the circumferential direction. The number of recesses 15 (protrusions 55) may be three or less, or may be five or more. In Fig. 12, the sealed blow molding die 50 is indicated by a virtual line (two-dot chain line).

[0111] In this way, by forming the recesses 15 (protrusions 55) spaced apart from one another along the circumferential direction, it is possible to prevent the container body 10 from cracking at the recesses 15 when an excessive force is applied to the mouth portion 11, for example, when the composite container 10A is dropped. In this case, it is also preferable that the recesses 15 (protrusions 55) are arranged at equal intervals from one another along the circumferential direction. This effectively prevents the plastic member 40a from moving relative to the body portion 20a of the preform 10a during blow molding.

[0112] Also in this modification, during blow molding, the plastic member 40a is pressed against the convex portion 55 of the blow molding die 50 that forms the recess 15, and movement of the plastic member 40a relative to the body portion 20a of the preform 10a can be prevented. This prevents a decrease in the yield of the composite container 10A. Furthermore, the plastic member 40 can cover a desired area of ​​the container body 10, effectively imparting desired functions and properties to the container body 10.

[0113] 13 and 14, a plurality of recesses 15 may be formed along the vertical direction. In the example shown in FIG. 14, two recesses 15 are formed spaced apart from each other along the vertical direction. One of the two recesses 15, recess 15a, is formed closer to the flange portion 17 than the other recess 15b. This recess 15a is formed so that its entirety is located within the neck portion 13. The other recess 15b is formed so as to straddle the neck portion 13 and the shoulder portion 12. The depths (radial distances) of recess 15a and recess 15b may be equal to each other or may be different from each other. The number of recesses 15 may be three or more.

[0114] In this case, the blow molding die 50 is provided with a plurality of protrusions 55 arranged in the vertical direction. In the example shown in FIG. 14, two protrusions 55 are formed spaced apart from each other in the vertical direction. One of the two protrusions 55, protrusion 55a, is formed at a position corresponding to recess 15a, and the other protrusion 55b is formed at a position corresponding to recess 15b. The heights (amounts of protrusion radially inward) of protrusions 55a and protrusions 55b (amounts of protrusion radially inward) may be equal to or different from each other. The number of protrusions 55 may be three or more.

[0115] In this way, by forming the recesses 15 (protrusions 55) spaced apart from each other in the vertical direction, it is possible to more effectively prevent the plastic member 40a from moving toward the bottom portion 30a relative to the body portion 20a during blow molding. Furthermore, the above-mentioned effects can also be obtained in this modified example.

[0116] The components disclosed in the above-described embodiment and each modification may be combined as needed, or some components may be omitted from all the components shown in the above-described embodiment and each modification. [Explanation of symbols]

[0117] 10 Container body 10A composite container 10a preform 11 Mouth 13 Neck 15 recess 20 Torso 30 bottom 40 Plastic parts 40a Plastic parts 50 blow molds 55 Convex part

Claims

1. In composite containers, a container body having a mouth, a neck, a body, and a bottom; a plastic member provided in close contact with the outside of the container body, A recess recessed radially inward is formed in the neck portion, The recessed portion is formed in a plurality of portions along the circumferential direction, The depth of the recess is greater than the thickness of the plastic member, The plastic member is recessed into the recess, The mouth portion includes a threaded portion and a flange portion provided below the threaded portion, A composite container, wherein the vertical distance from the deepest part of the recess to the lower surface of the flange portion is 1.5 mm or more and 5 mm or less.

2. The composite container according to claim 1 , wherein a plurality of the recesses are formed along the vertical direction.

3. 3. The composite container according to claim 1, wherein the depth of the recess is 0.2 mm or more and 0.8 mm or less.

4. A blow molding die for producing a composite container comprising a container body having a mouth, a neck, a body, and a bottom, and a plastic member provided in close contact with the outside of the container body, a protrusion protruding radially inward is formed at a position of the container body corresponding to the neck portion, The protrusions are formed in a plurality along the circumferential direction, The height of the protrusion is greater than the thickness of the plastic member, The mouth portion includes a threaded portion and a flange portion provided below the threaded portion, the blow molding die has a contact surface that comes into contact with the flange portion, A blow molding die, wherein the vertical distance from the contact surface to the tip of the convex portion is 1.5 mm or more and 5 mm or less.

5. The blow molding die according to claim 4 , wherein a plurality of the convex portions are formed along the vertical direction.

6. 6. The blow molding die according to claim 4, wherein the height of the convex portion is 0.2 mm or more and 0.8 mm or less.

7. In a method for manufacturing a composite container, providing a preform; providing a plastic member on the exterior of the preform; A step of preparing a blow molding die having a protrusion formed thereon that protrudes radially inward; a step of placing the preform and the plastic member in the blow molding die and pressing the convex portion of the blow molding die against the plastic member; Blow molding the preform and the plastic member in the blow mold to expand the preform and the plastic member together; a step of producing a container body corresponding to the preform and having a mouth, a neck, a body, and a bottom, and a plastic member provided in close contact with the outside of the container body, In the process of producing the container body and the plastic member provided in close contact with the outside of the container body, the shape of the convex portion of the blow molding mold is transferred to form a concave portion that is recessed radially inward in the neck portion of the container body after blow molding, The recessed portion is formed in a plurality of portions along the circumferential direction, The depth of the recess is greater than the thickness of the plastic member, The plastic member is recessed into the recess, The mouth portion includes a threaded portion and a flange portion provided below the threaded portion, A method for manufacturing a composite container, wherein the vertical distance from the deepest part of the recess to the lower surface of the flange portion is 1.5 mm or more and 5 mm or less.

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