JP3635977B2 - Two-layered preform for stretch blow molding - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a two-layer preform for stretch blow molding used when molding a plastic bottle or the like by a stretch blow molding method, particularly for a barrier plastic bottle that blocks oxygen, water vapor, ultraviolet rays, and the like. The present invention relates to a two-layered preform for stretch blow molding.
[0002]
[Prior art]
Conventionally, as a stretch blow molded container, a so-called PET bottle using polyethylene terephthalate has been widely used for beverages and the like, but its use is further expanded and a barrier PET bottle that protects the contents from ultraviolet rays, oxygen, and water vapor. Has come to be required.
[0003]
The production of this barrier PET bottle has been attempted by two-layer molding in which a layer made of a barrier resin is applied to the outer layer of a conventional PET bottle.
[0004]
As the above two-layer molding method, there is a method of stretch blow molding using a preform having a two-layer structure. For example, as shown in FIG. A cylindrical body portion (12) having a portion (16) and a bottom portion (14) at the lower end, and a hole-shaped portion (18) provided in the bottom portion (14), and formed by an outer plug made of a barrier resin. PET molded with a reform (10), a cylindrical body (22) having a mouth and neck (26) in the upper part and closely contacting the inner surface of the outer preform (10), and a bottom (24) at the lower end It was comprised by the inner side preform (20) made from.
[0005]
[Problems to be solved by the invention]
However, when the above two-layered preform is formed by stretch blow, the outer preform (10) is stretched by a stretch rod (70) inserted into the preform, for example, as shown in FIG. Cracks may occur at the bottom (14), or the extended bottom (14) may be displaced or peeled off from the bottom (24) of the inner preform (20), resulting in failure to obtain the desired barrier properties. There was a problem that the drop strength was impaired.
[0006]
Similarly, there is a problem that the flange portion of the outer preform is displaced from or peeled off from the mouth and neck portion of the inner preform.
[0007]
The present invention solves such problems of the prior art, and the object of the present invention is to form a barrier plastic bottle that blocks oxygen, water vapor, ultraviolet rays, and the like in a stretch blow molding, and the outer side having the barrier property is A double-layer plastic bottle that provides a two-layered preform that is free of cracks, misalignments, and peeling off the bottom barrier layer of a double-layer plastic bottle that is used as a barrier layer, and thus has a barrier property that is excellent in barrier properties and can withstand dropping. Is to provide.
[0008]
[Means for Solving the Problems]
In order to achieve the above object in the present invention, first, in the invention of claim 1, a cylindrical body having a flange at the upper end and a bottom at the lower end, and a hole is provided at the bottom. An outer preform made of a barrier resin, a neck portion at the upper end, a cylindrical body portion that is in close contact with the inner surface of the outer preform, and a bottom portion at the lower end. A two-layered preform for stretch blow molding constituted by an inner preform, provided with a substantially circular groove or protrusion on at least one side of the bottom of the outer preform in the vicinity of the peripheral edge of the hole, A stretch blow-molding two-piece film characterized in that the inner preform resin facing the hole forming part of the outer preform is filled in the hole forming part and further covers the outer surface of the bottom part of the outer preform. Layer structure It is obtained by the form.
[0009]
According to a second aspect of the present invention, a substantially circular groove or convex portion is provided on at least one side near the periphery of the flange portion at the upper end of the cylindrical body portion of the outer preform, and the flange portion of the outer preform is provided. 2. The two-layer structure preform for stretch blow molding according to claim 1, wherein the resin at the mouth / neck portion of the inner preform opposite to the cover is formed so as to cover the flange portion.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, the two-layered preform for stretch blow molding of the present invention comprises a cylindrical body (12) having a flange (16) at the upper end and a bottom (14) at the lower end, and It has an outer preform (10) made of a barrier resin formed by providing a hole (18) at the bottom (14), and a mouth neck (26) at the upper end, and the inner surface of the outer preform (10) A two-layered preform for stretch blow molding comprising a cylindrical body (22) that is in close contact with the inner body and an inner preform (20) made of a resin for a container body that is molded with a bottom (24) at the lower end. (1), as shown in FIG. 2 (a), at least one side of the bottom (14) in the vicinity of the periphery of the hole (18) of the outer preform (10) (the outer surface of the bottom (14) in the drawing) ), A substantially circular groove (14a) or a convex portion (not shown) The resin of the inner preform (20) facing the hole portion (18) of the outer preform (10) is filled in the hole portion (18), and the bottom of the outer preform (10) It is formed so as to cover the outer surface of (14).
[0011]
As shown in FIG. 2 (b), the substantially circular groove (14a) formed in the bottom (14) in the vicinity of the periphery of the hole forming portion (18) of the outer preform (10) is formed on both surfaces of the bottom (14). Further, as shown in FIG. 2 (c), a knurled eye (14b) having a plurality of substantially circular grooves and convex portions alternately formed on the outer surface or in FIG. 2 (d). As shown, it may be applied to both sides.
[0012]
Stretching of the barrier plastic bottle by forming the two-layered preform (1) for stretch blow molding in the shape of the bottom (14, 24) of the outer preform (10) and the inner preform (20) as described above. During blow molding, cracks occur in the bottom (14) of the outer preform (10) stretched by the stretching rod inserted into the stretch blow molding two-layered preform (1), or a substantially circular groove. Alternatively, the convex portion exhibits a locking function, and there is no occurrence of deviation or peeling from the bottom portion (24) of the inner preform (20), and thus the obtained barrier plastic bottle has barrier properties and drop strength. It can be made that there is no fall of.
[0013]
Further, as shown in FIG. 3 (a), the invention of claim 2 is at least one surface (the lower surface in the drawing) inside the periphery of the flange portion (16) at the upper end of the cylindrical body portion of the outer preform (10). Are provided with a substantially circular groove (16a) or a convex portion (not shown), and the mouth / neck portion (26) of the inner preform (20) facing the flange portion (16) of the outer preform (10). The resin is formed so as to cover the flange portion (16).
[0014]
The substantially circular groove (16a) may be the upper and lower surfaces of the flange portion (16) as shown in FIG. 3 (b), and the substantially circular groove and convexity as shown in FIG. 3 (c). A knurled stitch (16b) having a plurality of alternating portions may be formed on the lower surface or on both the upper and lower surfaces as shown in FIG. 2 (d).
[0015]
By forming the two-layer structure preform (1) for stretch blow molding in the shape of the flange portion (16) of the outer preform (10) and the mouth neck portion (26) of the inner preform (20) as described above, In the stretch blow molding of a barrier plastic bottle, the substantially circular groove or convex portion exerts a locking function, and the stretched flange portion (16) is displaced from the mouth and neck portion (26) of the inner preform. Alternatively, the barrier plastic bottle thus obtained does not peel off, and the barrier property and the drop strength are not reduced even in the vicinity of the flange portion (16) of the outer preform (10).
[0016]
The outer preform (10) constituting the light-shielding barrier packaging material (1) of the present invention is made of a barrier resin that blocks oxygen, water vapor, or ultraviolet rays, such as polyethylene naphthalate (PEN), ethylene / vinyl. Alcohol copolymer (EVOH), metaxylenediamine (MDX6), etc. are mentioned, and can be selected according to the intended use.
[0017]
For example, as shown in FIG. 4, the outer preform (10) is prepared by passing the heated barrier resin (R) from the resin injection gate (34) into the cavity (10 a) for the outer preform (10). After the injection filling, the molding die (40) is cooled to solidify the barrier resin (R) in the cavity (10a) to obtain the outer preform (10).
[0018]
To form a two-layered preform for stretch blow molding (1) using this outer preform (10), as shown in FIG. 5, a molding die for two-layered preform for stretch blow molding (50) The outer preform (10) obtained above is placed inside, and then the heated container body resin (Y) (polyethylene terephthalate (PET) is generally used) is injected into the resin injection gate (55). ) To fill the hole (18) in the cavity (50a) and in the outer preform (10), and further wrap-around the outer surface of the bottom (14) of the outer preform (10) to form the outer preform. Even in the vicinity of the flange portion (16) of (10), it is wound and formed so as to cover the lower surface of the flange portion (16), and then the molding die (50) is cooled to form a resin for the container body ( ) Solidified by stretch blow molding two-layer structure preform (1) is obtained a.
[0019]
【The invention's effect】
Since this invention is the above structure, there exist the following effects.
That is, an outer preform made of a barrier resin having a cylindrical body portion having a flange portion at the upper end and a bottom portion at the lower end and having a hole in the bottom portion, and a mouth and neck portion at the upper end. In a two-layer structure preform for stretch blow molding constituted by a cylindrical body portion that is in close contact with the inner surface of the outer preform and an inner preform made of resin for a container body that is molded with a bottom portion at the lower end, A substantially circular groove or projection is provided on at least one side of the bottom of the outer preform near the periphery of the hole forming portion, and the resin of the inner preform facing the hole forming portion of the outer preform is in the hole forming portion. Since it is filled and formed to cover the outer surface of the bottom of the outer preform, there is no crack, misalignment, or peeling near the bottom when molding a barrier plastic bottle by stretch blow. It is possible to provide a configuration preform.
[0020]
In addition, a substantially circular groove or convex portion is provided on at least one side near the periphery of the flange portion at the upper end of the cylindrical body portion of the outer preform, and the inner preform facing the flange portion of the outer preform is provided. Since the resin of the mouth and neck is formed so as to cover the flange, when the barrier plastic bottle is stretch blow molded, the inner preform near the stretched flange is displaced or peeled off from the mouth and neck. It is possible to provide a two-layered preform for stretch blow molding that does not have any.
[0021]
Thus, the obtained barrier plastic bottle can be made free from a decrease in barrier properties and drop strength in the vicinity of the bottom and flange of the bottle.
[0022]
Therefore, the present invention exhibits excellent practical effects as a two-layered preform for stretch blow molding for a barrier plastic bottle that contains a drink or the like and blocks oxygen, water vapor, or ultraviolet rays.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an explanatory view showing a cross-sectional side view of an embodiment of a two-layered preform for stretch blow molding of the present invention.
FIG. 2 is an enlarged view of an example of the bottom shape of a two-layered preform for stretch blow molding according to the present invention. FIG. 2 (a) shows a substantially circular groove formed on the bottom surface of the bottom of the outer preform. (B) is a case where substantially circular grooves are formed on both sides of the bottom of the outer preform. (C) is a knurled eye on the bottom lower surface of the outer preform, and (d) is a knurled eye on both bottom surfaces of the outer preform.
FIG. 3 is an enlarged view of an example of the flange part shape of the two-layered preform for stretch blow molding of the present invention. FIG. 3 (a) shows a substantially circular groove formed on the lower surface of the flange part of the outer preform. (B) is an example in which substantially circular grooves are provided on both surfaces of the flange portion of the outer preform. (C) is an example in which knurls are provided on the lower surface of the flange portion of the outer preform, and (d) is an example in which knurls are provided on both surfaces of the flange portion of the outer preform.
FIG. 4 is an explanatory diagram showing, in a side cross-section, an example of molding of an outer preform constituting the two-layered preform for stretch blow molding of the present invention.
FIG. 5 is an explanatory view showing an example of molding of a two-layered preform for stretch blow molding of the present invention in a side section.
FIG. 6 is an explanatory view showing an example of a conventional two-layered preform for stretch blow molding in a side section.
FIG. 7 is an explanatory diagram showing, in a side cross-section, an example of stretch blow molding using a conventional stretch blow molding two-layered preform.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Two-layer structure preform 10 for stretch blow molding Outer preform 12 Outer preform body 14 ... Outer preform bottom 14a ... Bottom substantially circular groove 14b ... Bottom knurled eye 16. Flange 16a of outer preform 16 ... Circular groove 16b of flange 16 Knurled 18 of flange 18 ... Hole 20 in bottom of outer preform 22 ... Inside preform 22 ... Inside preform Body 24 ························································ Barrier resin injection gate 40 ··· Molding die for outer preform 50 ··· Two-layer structure for stretch blow molding Reform molding die 50a ... Two-layered preform cavity for stretch blow molding 55 ... Resin injection gate for container body 56 ... Core body 70 ... Extension Rod R ‥‥ barrier resin Y ‥‥ container body for resin V ‥‥ blow pressure direction

Claims (2)

A cylindrical body portion having a flange portion at the upper end and a bottom portion at the lower end, and an outer preform made of a barrier resin formed by providing a hole in the bottom portion, and a mouth and neck portion at the upper end, A two-layer construction preform for stretch blow molding composed of a cylindrical body portion that is in close contact with the inner surface of the outer preform and an inner preform made of a resin for a container body that is molded with a bottom portion at the lower end, A substantially circular groove or projection is provided on at least one surface of the bottom of the outer preform in the vicinity of the peripheral edge of the hole, and the resin of the inner preform facing the hole of the outer preform is in the hole. A two-layer structure preform for stretch blow molding, which is filled and formed so as to cover the outer surface of the bottom of the outer preform. Provided with a substantially circular groove or projection on at least one side inside the periphery of the flange at the upper end of the cylindrical body of the outer preform, and the neck and neck of the inner preform facing the flange of the outer preform The two-layer structure preform for stretch blow molding according to claim 1, wherein the resin of the portion is formed so as to cover the flange portion.

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