The present disclosure relates to a synthetic resin preform including a colored layer, which forms a gradation region in which a layer thickness gradually decreases, and to a bottle obtained by biaxially stretch blow molding such a preform. In detail, the present disclosure is to achieve a favorable gradation pattern.
Regarding bottles that are made of synthetic resin, such as polyethylene terephthalate (PET), and that are used in various fields, such as beverages, foods, and cosmetics, such a bottle is known to be biaxially stretch blow molded and decorated with gradations associated with color density. The gradations may be caused to appear by changing the color density in the upward and the downward direction (i.e., a direction extending along the axis of the bottle). (Refer to, for example, Patent Literature 1.) In Patent Literature 1, a gradation pattern is obtained by disposing an intermediate layer, made of colored resin, in between transparent base material layers by co-injection molding using a three-layer nozzle.
PTL 1: JP2006334849A
However, a conventional bottle as described in Patent Literature 1 poses the problem that the gradation pattern cannot be emphasized due to colorless transparency of the base material layers. Although one possible way to address this is to add a coloring agent to the base material, this also faces the problem that the intermediate layer is hidden, thereby making the gradation pattern invisible.
The present disclosure has been developed in view of the aforementioned current situation, and the present disclosure is to provide a preform and a bottle by which a favorable gradation pattern is achieved.
Summary and features of the present disclosure are as follows.
1. A synthetic resin preform including a colored layer forming a gradation region in which a layer thickness gradually decreases, wherein,
on an outer circumferential side of a base material layer made of a first colored resin, the colored layer, which is made of a second colored resin having a color different from that of the first colored resin and which forms the gradation region in which the layer thickness gradually decreases upward, is formed, and, on the outer circumferential side of the colored layer, a coating layer made of the first colored resin is formed.
2. The preform according to the above item 1, wherein
the preform is molded, from a state where the first colored resin is filled in a gate disposed in correspondence with a middle of a bottom of the preform, by injecting the first colored resin into a cavity of a mold through the gate for a first predetermined time period and by injecting the second colored resin material for a second predetermined time period, and
by setting a starting time point of the first predetermined time period to be behind a starting time point of the second predetermined time period, setting a finishing time point of the first predetermined time period to be behind a finishing time period of the second predetermined time period, and setting an injection rate of the second colored resin to be faster than an injection rate of the first colored resin, the first colored resin is caused to flow while stretching the second color resin after penetrating a center portion of the second colored resin located inside the cavity of the mold, and
the colored layer is formed on the outer circumferential side of the base material layer, and the coating layer is formed on the outer circumferential side of the colored layer.
3. The preform according to the above item 1 or 2, wherein the first colored resin has an IV in the range from 0.5 to 0.63.
4. A bottle obtained by biaxially stretch blow molding the preform according to any one of the items 1 to 3 and decorated with gradations associated with color density that are caused to appear by the colored layer.
According to the present disclosure, since the colored layer made of the second colored resin, which has a color different from that of the first colored resin, is formed on the outer circumferential side of the base material layer made of the first colored resin, the gradation pattern is emphasized. Furthermore, since the coating layer made of the first colored resin is formed on the outer circumferential side of the colored layer, transition in density of the gradation pattern is obscured with the thin coating layer covering the colored layer. Thus, a favorable gradation pattern is achieved.
Accordingly, the present disclosure provides a preform and a bottle by which the favorable gradation pattern is achieved.
In the accompanying drawings:
The following describes a preform 1 and a bottle 8 according to one of embodiments of the present disclosure in more detail by way of illustration with reference to
Herein, the upward and the downward direction refers to a direction extending along the axis of the preform 1. The term upward refers to a direction extending from a bottom 2 to a mouth 4 of the preform 1, and the term downward refers to a direction opposite thereto.
As illustrated in
Moreover, an inner colored layer 6b, which is made of the second colored resin R2, is formed on the inner circumferential side of the base material layer 5. Thus, the preform 1 has, in the gradation region Gr, a four-layer structure including the coating layer 7 (the first colored resin R1)/the outer colored layer 6a (the second colored resin R2)/the base material layer 5 (the first colored resin R1)/the inner colored resin 6b (the second colored resin R2) from the outer circumferential side to the inner circumferential side. Additionally, the preform 1 according to the present embodiment is used to obtain a beverage bottle having a weight of 22 g and may be biaxially stretch blow molded to form a bottle of, for example, 266 ml, 542 ml, or 579 ml.
The preform 1 with the above configuration may be produced according to the following outline. That is to say, the preform 1 is molded, from the state where the first colored resin R1 is filled in a gate disposed in correspondence with the middle of a bottom 2 of the preform 1, by injecting the first colored resin R1 into a cavity of a mold through the gate for a first predetermined time period and by injecting the second colored resin material R2 for a second predetermined time period, with use of a two-layer gate nozzle. For instance, as illustrated in
Herein, the first predetermined time period may be 7 seconds, the second predetermined time period may be 0.68 second, and a delay time period of the starting time point T1s of the first predetermined time period with respect to the starting time point T2s of the second predetermined time period may be 0.1 second. The injection rate of the second colored resin R2 may be 80 mm/s, and the injection rate of the first colored resin R1 may be 6 mm/s.
By co-injection molding the first colored resin R1 and the second colored resin R2 at the injection timing and injection rates as described above, the resins R1 and R2 are flown as illustrated in
According to the preform 1 of the present embodiment described above, the bottle 8, which is decorated with gradations associated with color density that are caused to appear by the outer colored layer 6a as illustrated in
Additionally, to achieve the favorable gradation pattern Gm, an intrinsic viscosity (IV) of the first colored resin R1 is preferably in the range from 0.5 to 0.63 and more preferably in the range from 0.6 to 0.63.
Although the preform 1 and the bottle 8 according to the embodiment has been described to be used in beverage application, as a modification, those used in toiletry application as illustrated in
The description above is considered to be merely illustrative of one of embodiments of the present disclosure, and various changes may be made within the scope of the claims. For example, one or both of the first colored resin R1 and the second colored resin R2 may be polypropylene (PP) instead of PET. Furthermore, the first colored resin R1 and the second colored resin R2 does not need to be colorless and transparent and may be colored and transparent depending on purposes.
Number | Date | Country | Kind |
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2014-174354 | Aug 2014 | JP | national |
This is a Continuation of application Ser. No. 15/324,234 filed Jan. 5, 2017, which in turn is a national stage entry of PCT/JP2015/003967 filed Aug. 6, 2015, which claims priority to JP 2014-174354 filed Aug. 28, 2014. The disclosure of each of the prior applications is hereby incorporated by reference herein in its entirety.
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Number | Date | Country | |
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20190143576 A1 | May 2019 | US |
Number | Date | Country | |
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Parent | 15324234 | US | |
Child | 16250226 | US |