JP2017007264A - Preform, plastic bottle, and method for producing plastic bottle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a preform satisfactory in injection moldability when a preform is molded by an injection molding machine, and satisfactory in blow moldability when a lightweight bottle is molded from the preform by a blow molding machine, a plastic bottle, and a method for producing the plastic bottle.SOLUTION: In a preform 10 provided with a mouth part 11 and a barrel part 20, the barrel part 20 includes a large-sized part 21, a constriction part 22, a small-sized part 23 and a bottom part 24, and the barrel part 20 includes a thin part 25, a thickness increased part 26 and a prescribed thickness part 27; the whole length L2 of the barrel part being 42-65 mm, the ratio L4/L2 of the distance L4 to the lower edge of the thin part 25 directly below a support ring 14 to the whole length L2 being 0.02-0.25, the ratio L6/L2 of the distance L6 to the upper end of the constriction part 22 directly below the support ring 14 to the whole length L2 being 0.02-0.20, and the weight being 17 g or below.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a preform, a plastic bottle, and a method for manufacturing a plastic bottle, and more particularly to a lightweight preform, a plastic bottle, and a method for manufacturing a plastic bottle.

  For example, a plastic bottle is used as a container filled with a beverage. In the production of plastic bottles, a method is often used in which a test tubular preform is molded from a resin with an injection molding machine, and the preform is molded into a bottle with a blow molding machine.

  The production volume of plastic bottles is increasing year by year. On the other hand, the plastic bottles are lightened by reducing the amount of raw materials used from the viewpoint of reducing energy consumption and carbon dioxide emissions by saving resources, reducing waste, and reducing the environmental impact during transportation. Is addressed.

  Since the weight of the plastic bottle depends on the weight of the preform resin before being blow-molded by the blow molding machine, the weight of the plastic bottle is reduced by reducing the weight of the preform. However, when the weight of the plastic bottle is reduced, the thickness of the plastic bottle is reduced as a whole, and the conditions for molding the plastic bottle become more severe. Therefore, it is necessary to design a preform for satisfactorily molding a light weight plastic bottle. Further, since the preform is molded by an injection molding machine from the viewpoint of production, it is also important that the preform has good injection moldability.

  As a preform for reducing the weight of a plastic bottle, a preform in which a thin parallel portion is provided under a support ring is known (for example, Patent Document 1). A preform is also known in which the outer diameter of the body portion is smaller than the outer diameter of the mouth portion (for example, Patent Document 2).

JP 2003-53823 A JP 2007-296720 A

  Here, as in Patent Document 1, when the plastic bottle is reduced in weight by forming a thin parallel portion under the preform support ring, the amount of resin under the support ring is reduced. However, there are limits to making plastic bottles lighter. In addition, in a preform having such a thin part, when the preform is molded by an injection molding machine, the flow of the resin tends to be deteriorated at a part corresponding to the part where the cavity thickness is thin. And molding defects such as welds may occur.

  In addition, the upper limit of the stretch ratio of a preform when molding a plastic bottle from a preform with a blow molding machine depends largely on the stretch characteristics of the resin constituting the preform, so it depends on the size of the plastic bottle to be molded. Therefore, the size of the preform is limited to some extent. In addition, a stretch rod is inserted into the preform during blow molding. For this reason, as in Patent Document 2, when the plastic bottle is further reduced in weight by forming the outer diameter of the body portion of the preform thinner, the thickness of the body portion is limited.

  In addition, when making plastic bottles lighter, by providing a thin part on the body of the preform, or by forming the outer diameter of the body to be thin, There is a difference in stretchability (ease of stretching). Due to this difference in stretchability, shaping defects such as uneven thickness, thinning, or whitening of the plastic bottle may occur. Therefore, a preform having good blow moldability is desired.

  Therefore, the object of the present invention is that the injection moldability when a preform is molded by an injection molding machine is good, and the blow moldability when a lightweight bottle is molded from a preform by a blow molding machine is good. An object is to provide a preform, a plastic bottle, and a method for producing the plastic bottle.

In order to solve the above-mentioned problem, the present invention provides a bottomed cylindrical preform comprising a mouth portion having a support ring at a lower end and a body portion continuously provided at the lower end of the support ring.
The trunk is
A large diameter portion connected to the lower end of the support ring;
A constricted portion continuously provided at the lower end of the large-diameter portion and reducing in diameter downward;
A small diameter portion connected to the lower end of the constricted portion;
And a bottom portion continuously provided at the lower end of the small diameter portion,
The barrel has portions with different thicknesses,
A thin portion in which the minimum thickness is uniformly formed downward from the lower end of the support ring; and
A thickness increasing portion formed so that the thickness gradually increases from the lower end of the thin portion downward,
A predetermined thickness portion having a uniform thickness formed downward from the lower end of the thickness increase portion,
The overall length L2 of the trunk is 42 mm or more and 65 mm or less,
The ratio L4 / L2 of the distance L4 from directly below the support ring to the lower end of the thin part with respect to the total length L2 of the trunk part is 0.02 or more and 0.25 or less,
The ratio L6 / L2 of the distance L6 from directly below the support ring to the upper end of the constricted part with respect to the full length L2 of the trunk part is 0.02 or more and 0.20 or less,
The weight is 17 g or less.

  Furthermore, a ratio L7 / L2 of a distance L7 from directly below the support ring to the lower end of the constricted portion with respect to the total length L2 of the trunk portion is 0.10 or more and 0.40 or less.

  A ratio L5 / L2 of a distance L5 from directly below the support ring to the lower end of the thickness increasing portion with respect to the total length L2 of the trunk portion is 0.10 or more and 0.32 or less.

  Furthermore, a ratio T1 / T2 of the thickness T1 of the thin portion to the thickness T2 of the predetermined thickness portion is 0.60 or more and 0.85 or less.

  Furthermore, the ratio D4 / D3 of the outer diameter D4 of the small diameter portion to the outer diameter D3 of the large diameter portion is 0.60 or more and 0.90 or less.

  Further, the bottom portion is formed so that the thickness gradually decreases from the lower end of the small diameter portion to the center of the bottom portion.

  Furthermore, the ratio T3 / T1 of the thickness T3 of the bottom center to the thickness T1 of the thin portion is 1.01 or more and 1.30 or less.

  Further, the lower end of the thin portion is located in the constricted portion.

  Furthermore, the lower end of the thickness increase part is located in the constriction part.

  Furthermore, the plastic bottle according to the present invention is characterized in that the above-mentioned preform is formed into a bottle shape by a blow molding machine.

  Further, the molding by the blow molding machine is a biaxial stretch blow in which the stretching ratio in the longitudinal direction is 1.3 times or more and 3.6 times or less, and the stretching ratio in the transverse direction is 2.0 times or more and 4.1 times or less. It is a molding.

  Furthermore, the thickness of the body after molding is 0.05 mm or more and 0.18 mm or less.

  Further, the lower portion of the large diameter portion and the constricted portion form a shoulder portion that is inclined with respect to the horizontal direction.

Furthermore, the method for manufacturing a plastic bottle according to the present invention includes a mouth portion having a support ring at a lower end, and a body portion connected to the lower end of the support ring, and the body portion is provided at a lower end of the support ring. A continuous large-diameter portion, a constricted portion continuously connected to a lower end of the large-diameter portion, and having a diameter reduced downward, a small-diameter portion continuously provided to a lower end of the constricted portion, and a lower-end of the small-diameter portion A bottom portion that is continuous with the body portion, the body portion having a portion having a different thickness, and a thin portion having a minimum thickness uniformly formed downward from a lower end of the support ring, A thickness increasing part formed so that the thickness gradually increases from the lower end of the thin part downward, and a predetermined thickness part uniformly formed from the lower end of the thickness increasing part downward The overall length L2 of the trunk is 42 mm or more and 65 mm or less, The ratio L4 / L2 of the distance L4 from directly below the support ring to the lower end of the thin part with respect to the total length L2 of the part is 0.02 or more and 0.25 or less, and immediately below the support ring with respect to the full length L2 of the trunk part A step of manufacturing a preform having an L6 / L2 ratio L6 / L2 of 0.02 to 0.20 and a weight of 17 g or less with an injection molding machine from the distance L6 to the upper end of the constricted portion;
And a step of forming the preform into a bottle shape with a blow molding machine.

  According to the present invention, in the bottomed cylindrical preform comprising a mouth portion having a support ring at a lower end and a body portion continuously provided at the lower end of the support ring, the body portion is a lower end of the support ring. A constricted portion that is continuously provided at the lower end of the large-diameter portion, and has a diameter that is reduced downward, a small-diameter portion that is continuously provided at the lower end of the constricted portion, and A bottom portion connected to the lower end, the body portion has a portion having a different thickness, and a thin portion in which a minimum thickness is uniformly formed downward from the lower end of the support ring; A thickness increasing portion formed so that the thickness gradually increases downward from the lower end of the thin portion, and a predetermined thickness formed uniformly from the lower end of the thickness increasing portion downward. A total length L2 of the barrel is 42 mm or greater and 65 mm or less, and the barrel The ratio L4 / L2 of the distance L4 from just below the support ring to the lower end of the thin portion with respect to the total length L2 is 0.02 or more and 0.25 or less, and from directly below the support ring with respect to the full length L2 of the trunk portion Since the ratio L6 / L2 of the distance L6 to the upper end of the constricted portion is 0.02 or more and 0.20 or less and the weight is 17 g or less, the injection moldability when the preform is molded by the injection molding machine In addition, it is possible to improve the blow moldability when a lightweight bottle is formed from a preform by a blow molding machine.

  Furthermore, according to the configuration in which the ratio L7 / L2 of the distance L7 from directly below the support ring to the lower end of the constricted portion with respect to the full length L2 of the trunk portion is 0.10 or more and 0.40 or less, the injection molding machine The injection moldability when the preform is molded can be made better, and the blow moldability when the light weight bottle is molded from the preform by a blow molding machine can be made better.

  According to the configuration in which the ratio L5 / L2 of the distance L5 from directly below the support ring to the lower end of the thickness increasing portion with respect to the full length L2 of the trunk portion is 0.10 or more and 0.32 or less, The injection moldability when the preform is molded can be made better, and the blow moldability when the light weight bottle is molded from the preform by a blow molding machine can be made better.

  Further, according to the configuration in which the ratio T1 / T2 of the thickness T1 of the thin portion to the thickness T2 of the predetermined thickness portion is 0.60 or more and 0.85 or less, the preform is molded by the injection molding machine. In addition to making the injection moldability at the time of being made better, it is possible to make the blow moldability better when a lightweight bottle is formed from a preform by a blow molding machine.

  Furthermore, according to the configuration in which the ratio D4 / D3 of the outer diameter D4 of the small diameter portion to the outer diameter D3 of the large diameter portion is 0.60 or more and 0.90 or less, the preform is molded by the injection molding machine. It is possible to improve the injection moldability at the time of molding, and to improve the blow moldability when the lightweight bottle is molded from the preform by a blow molding machine.

  Furthermore, according to the configuration in which the bottom portion is formed so that the thickness gradually decreases from the lower end of the small diameter portion to the center of the bottom portion, the injection moldability when the preform is molded by the injection molding machine is improved. In addition to the improvement, it is possible to improve the blow moldability when a lightweight bottle is formed from a preform by a blow molding machine.

  Furthermore, according to the configuration in which the ratio T3 / T1 of the thickness T3 of the bottom center to the thickness T1 of the thin portion is 1.01 or more and 1.30 or less, the preform is molded by the injection molding machine. The injection moldability at the time can be improved, and the blow moldability when the light weight bottle is formed from the preform by a blow molding machine can be improved.

  Furthermore, according to the structure in which the lower end of the thin part is located in the constricted part, the injection moldability is improved when the preform is molded by the injection molding machine, and the weight is reduced from the preform by the blow molding machine. Blow moldability when the bottle is molded can be made better.

  Furthermore, according to the configuration in which the lower end of the thickness increasing portion is located in the constricted portion, the injection molding machine can improve the injection moldability when the preform is molded, and the preform can be blown by the blow molding machine. Blow moldability when the lightweight bottle is molded can be improved.

  Furthermore, in the plastic bottle according to the present invention, since the above-described preform is formed into a bottle shape by a blow molding machine, a plastic bottle reduced in weight with good blow moldability can be formed from the preform.

  Further, the molding by the blow molding machine is a biaxial stretch blow in which the stretching ratio in the longitudinal direction is 1.3 times or more and 3.6 times or less, and the stretching ratio in the transverse direction is 2.0 times or more and 4.1 times or less. According to the structure which is shaping | molding, the plastic bottle reduced in weight by the better blow moldability from a preform can be shape | molded.

  Furthermore, according to the configuration in which the thickness of the body portion after molding is 0.05 mm or more and 0.18 mm or less, a plastic bottle reduced in weight with better blow moldability can be molded from the preform. .

  Furthermore, according to the configuration in which the lower portion of the large diameter portion and the constricted portion form a shoulder portion that is inclined with respect to the horizontal direction, a plastic bottle reduced in weight from the preform with better blow moldability can be obtained. Can be molded.

  Furthermore, the method for manufacturing a plastic bottle according to the present invention includes a mouth portion having a support ring at a lower end, and a body portion connected to the lower end of the support ring, and the body portion is provided at a lower end of the support ring. A continuous large-diameter portion, a constricted portion continuously connected to a lower end of the large-diameter portion, and having a diameter reduced downward, a small-diameter portion continuously provided to a lower end of the constricted portion, and a lower-end of the small-diameter portion A bottom portion that is continuous with the body portion, the body portion having a portion having a different thickness, and a thin portion having a minimum thickness uniformly formed downward from a lower end of the support ring, A thickness increasing part formed so that the thickness gradually increases from the lower end of the thin part downward, and a predetermined thickness part uniformly formed from the lower end of the thickness increasing part downward The overall length L2 of the trunk is 42 mm or more and 65 mm or less, The ratio L4 / L2 of the distance L4 from directly below the support ring to the lower end of the thin part with respect to the total length L2 of the part is 0.02 or more and 0.25 or less, and immediately below the support ring with respect to the full length L2 of the trunk part A step of producing a preform having an L6 / L2 ratio L6 / L2 of 0.02 to 0.20 and a weight of 17 g or less with an injection molding machine from the distance L6 to the upper end of the constricted portion; It is possible to produce a preform with good injection moldability and to produce a plastic bottle reduced in weight with good blow moldability from the preform. Can do.

It is the front view in which an example of the preform concerning this embodiment was shown. It is sectional drawing of the preform of FIG. It is the schematic by which an example of the injection molding apparatus for manufacturing a preform was shown. It is sectional drawing by which an example of the heating apparatus of preform was shown. FIG. 2 is a cross-sectional view schematically showing a preform and a PET bottle after blow molding. It is the front view in which the PET bottle formed from the preform which concerns on this embodiment was shown. It is the front view by which another PET bottle formed from the preform which concerns on this embodiment was shown. It is sectional drawing in which the preform of the comparative example was shown.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, the configuration of a preform (preliminary body) for molding a PET (PolyEthylene Terephthalate) bottle according to the present embodiment will be described in detail. FIG. 1 is a front view showing an example of a preform 10 according to the present embodiment. 2 is a cross-sectional view of the preform 10 of FIG. In the following, for convenience of explanation, the mouth portion 11 of the preform 10 in the state of FIG. 1 in which the open side on one end side of the preform 10 faces upward is referred to as the upper side.

  The preform 10 according to the present embodiment has a bottomed cylindrical shape that is open at one end side, and includes a mouth portion 11 on the open side and a body portion 20 on the bottom side. The mouth part 11 has a circular opening 12 at its upper end and an annular support ring 14 protruding outward at its lower end.

  On the outer periphery of the mouth portion 11, there is provided a screw portion 13 for attaching a lid (not shown) after the preform 10 is formed into a bottle shape by a blow molding machine. Further, between the screw portion 13 and the support ring 14, an annular cover 15 that protrudes outward is provided. Further, the shape of the mouth portion 11 does not change even after being molded by the blow molding machine. Therefore, it is preferable that the inner diameter D1 and the outer diameter D2 (corresponding to the thread valley diameter) of the mouth portion 11 of the preform 10 are, for example, the dimensions that are typically used in beverage PET bottles (see FIG. 2). .

  For example, the mouth 11 may have dimensions corresponding to the PCO 1810 standard or the PCO 1881 standard. More specifically, the inner diameter D1 of the mouth portion 11 is preferably 21.74 mm ± 0.13 mm. Furthermore, the outer diameter D2 of the mouth portion 11 is preferably 24.94 mm ± 0.13 mm. The distance from the lower surface of the support ring 14 to the upper end of the mouth portion 11 is the length L1 of the mouth portion 11. More specifically, the length L1 of the mouth portion 11 is preferably either 21.00 mm ± 0.25 mm (PCO1810 standard) or 17.00 mm ± 0.25 mm (PCO1881 standard).

  The trunk | drum 20 is a cylindrical shape, Comprising: It is a part which swells so that it may become a bottle shape in the case of blow molding. The trunk portion 20 is connected to the lower end (lower surface) of the support ring 14 of the mouth portion 11. The body portion 20 includes a large diameter portion 21 provided continuously with the lower end of the support ring 14, a constricted portion 22 provided continuously with the lower end of the large diameter portion 21, and a small diameter provided continuously with the lower end of the constricted portion 22. Part 23 and a bottom part 24 connected to the lower end of the small diameter part 23. The distance from the lower surface of the support ring 14 to the lower end of the bottom portion 24 is the total length L2 of the trunk portion 20.

  The large diameter part 21 and the small diameter part 23 are cylindrical, and the outer diameter D3 of the large diameter part 21 is larger than the outer diameter D4 of the small diameter part 23. The constricted portion 22 is configured in a truncated cone shape by gradually reducing the diameter downward, that is, from the large diameter portion 21 side toward the small diameter portion 23 side. The upper end and the lower end of the constricted portion 22 are smoothed to the lower end of the large diameter portion 21 and the upper end of the small diameter portion 23, respectively. The outer diameter at the upper end of the constricted portion 22 is the outer diameter D3 of the large diameter portion 21, and the outer diameter at the lower end is the outer diameter D4 of the small diameter portion 23.

  The trunk | drum 20 has the part from which the thickness is not constant and differs in thickness. And the trunk | drum 20 is directed toward the downward direction from the lower end of the thin part 25, and the thin part 25 in which the minimum thickness was uniformly formed toward the downward direction from the lower end of the support ring 14 of the opening | mouth part 11 about the thickness. The thickness increasing portion 26 is formed so that the thickness gradually increases, and the predetermined thickness portion 27 is formed with a uniform thickness downward from the lower end of the thickness increasing portion 26. The wall thickness at the upper end of the wall thickness increasing portion 26 is the wall thickness T1 of the thin wall portion 25, and the wall thickness at the lower end is the wall thickness T2 of the predetermined wall thickness portion 27. Further, the lower end of the predetermined thick portion 27 corresponds to the lower end of the small diameter portion 23.

  The bottom 24 is formed in a substantially hemispherical shape that curves outward. The bottom 24 is formed so that the thickness gradually decreases from the lower end to the center of the small diameter portion 23. The bottom 24 may be conical, cylindrical with rounded corners, or other shapes. The bottom portion 28 is attached with a solidified portion formed incidentally at the molten resin inlet (gate) when the preform 10 is produced by injection molding. 1 and 2 show a form after the portion is cut off. Here, a relationship of T1 <T3 <T2 is established among the thickness T1 of the thin portion 25, the thickness T2 of the predetermined thickness portion 27, and the thickness T3 of the bottom center 28.

  In this manner, the body portion 20 is formed with a constricted portion 22 that gradually decreases in diameter from the large diameter portion 21 side toward the small diameter portion 23 side, thereby reducing the weight of the preform 10. . Moreover, the trunk | drum 20 has the thin part 25 in which the minimum thickness was uniformly formed immediately under the support ring 14, and the weight reduction of the preform 10 is achieved. Further, the bottom portion 24 of the trunk portion 20 is formed so that the thickness gradually decreases toward the center, and the weight of the preform 10 is also reduced by this configuration.

  Here, in the preform 10 according to the present embodiment, the overall length L2 of the trunk portion 20 is 42 mm or more and 65 mm or less, and the distance L4 from the position immediately below the support ring 14 to the lower end of the thin portion 25 with respect to the overall length L2 of the trunk portion 20. The ratio L4 / L2 is 0.02 or more and 0.25 or less, and the ratio L6 / L2 of the distance L6 from the position immediately below the support ring 14 to the upper end of the constricted portion 22 with respect to the total length L2 of the body portion 20 is 0.02 or more. 0.20 or less, and the weight is 17 g or less. And although mentioned later for details, the thin part 25 and the constriction part 22 are formed in this way with respect to the trunk | drum 20, and the injection moldability at the time of shape | molding the preform 10 with an injection molding machine is improved. In addition to being good, when the preform 10 is molded into a bottle shape by a blow molding machine, the preform 10 is configured to have an appropriate stretchability from just below the support ring 14 to the constricted portion 22. Note that the preform 10 is designed in consideration of not only injection moldability and blow moldability but also transportability. Therefore, the preform 10 according to the present embodiment exhibits comprehensively excellent performance from a raw material to a product.

  Next, an example of the manufacturing method of the preform 10 according to the present embodiment will be described in detail. FIG. 3 is a schematic view showing an example of an injection molding apparatus 40 for manufacturing the preform 10. The injection molding apparatus 40 includes a hopper dryer 41, a hopper 42, a heating cylinder 43, and a mold 44.

  The hopper dryer 41 is an inlet for, for example, a pellet-shaped molding material that is a main raw material of the preform 10. The hopper dryer 41 is configured to send the molding material to the hopper 42 after drying. The hopper dryer 41 is only required to dry the charged molding material to a predetermined moisture content, and may be, for example, a hot air drying type, a dehumidifying hot air drying type, or a reduced pressure heat transfer drying type.

  The injection molding apparatus 40 is configured such that the molding material put into the hopper 42 is melt plasticized by the heating cylinder 43 and sent out to the mold 44. The cylindrical heating cylinder 43 includes a heater (not shown) on the outer periphery and a screw (not shown) for injection into the mold 44 inside. The heating cylinder 43 is configured to heat the molding material to, for example, 270 ° C. to 300 ° C. by heat transfer from the heater.

  A cavity 44 that is a space portion corresponding to the shape of the preform 10 as a molded product is formed in the mold 44 divided into a plurality of parts. The cavity 45 is formed so as to correspond to the shape having the characteristics of the preform 10 according to this embodiment. The molding material injected from the heating cylinder 43 is configured to be injected into the cavity 45. The mold 44 is provided with a heater (not shown) for heating the mold 44 and a cooler (not shown) for cooling the mold 44. The mold 44 is configured such that the melted molding material is injected into the cavity 45 heated by the heater and pressurized, and then cooled by a cooler to mold the preform 10.

  Such an injection molding apparatus 40 is used to manufacture the preform 10. First, the PET resin that has been dried by the hopper dryer 41 of the injection molding device 40 and then put into the hopper 42 is melt-plasticized by the heating cylinder 43 and injected into the mold 44. The preform 10 is molded by injecting and pressurizing the PET resin from the heating cylinder 43 into the cavity 45 of the mold 44 and then cooling by a cooler.

  The molded preform 10 may be box-packed, so-called palletized, and temporarily stored in a warehouse or the like, or may be continued to the next step as it is. That is, a so-called cold parison method (two-stage method) in which the preform 10 and the blow molding are performed in different places or apparatuses may be used. The preform 10 and the blow molding are the same. A so-called hot parison method (one-stage method) performed at a place or an apparatus may be used. Furthermore, the manufacturing process from the molding of the preform 10 to the filling of the contents may be continuous inline.

  Next, an example of a method for forming a bottle shape from the preform 10 according to the present embodiment will be described in detail. When the preform 10 is formed into a bottle shape, the preform 10 is first heated. FIG. 4 is a sectional view showing an example of the heating device 50 of the preform 10. FIG. 4 shows a cross section perpendicular to the conveying direction of the preform 10.

  The heating device 50 includes a transport device 51 and a heater 52. The conveying device 51 is configured to convey the preform 10 while rotating the preform 10 about the axis of the preform 10 in order to uniformly heat the preform 10 in the circumferential direction. The heater 52 includes a plurality of halogen lamps, for example, and is configured to heat the preform 10 at a temperature suitable for blow molding, for example, 80 ° C. to 140 ° C. Further, the heating device 50 includes a reflecting plate 53 for reflecting the heat from the heater 52 to the preform 10, a shielding member 54 for preventing the heat from the heater 52 from escaping to the outside of the heating device 50, and the like. May be provided. In the heating device 50 of FIG. 4, the preform 10 is conveyed and heated with the mouth portion 11 facing downward.

  Here, the body portion 20 of the preform 10 according to the present embodiment is connected to the lower end of the support ring 14, the large diameter portion 21, and the large diameter portion 21, and is contracted toward the bottom portion 24. It has a constricted portion 22 having a diameter and a small-diameter portion 23 connected to the constricted portion 22. That is, the positional relationship between the heater 52 and the body portion 20 is closest to the large-diameter portion 21, gradually becomes farther from the large-diameter portion 21 side of the constricted portion 22 toward the small-diameter portion 23, and the small-diameter portion 23 is the closest. It is configured to be far away. Therefore, the large-diameter portion 21 having a close positional relationship with the heater 52 is likely to be warmed and easily stretched. On the other hand, compared with the large-diameter portion 21, the constricted portion 22 is gradually less likely to be warmed toward the bottom portion 24 (upward in FIG. 4), and thus is less likely to be gradually stretched toward the bottom portion 24. .

  The body portion 20 includes a thin portion 25 having a minimum thickness uniformly formed from the lower end of the support ring 14 toward the bottom portion 24 (upward in FIG. 4), and from the thin portion 25 to the bottom portion 24 side. A thickness increasing portion 26 formed so as to gradually increase in thickness toward the bottom, and a predetermined thickness portion 27 formed uniformly from the thickness increasing portion 26 toward the bottom 24. . That is, the body portion 20 is easily stretched because the thin portion 25 having the minimum thickness is easily heated. On the other hand, as compared with the thin portion 25, the thickness increasing portion 26 is gradually less likely to be warmed toward the bottom portion 24, and thus is not easily extended toward the bottom portion 24 side.

  The preform 10 has a total length L2 of the body portion 20 of 42 mm or more and 65 mm or less, and a ratio L4 / L2 of a distance L4 from directly below the support ring 14 to the lower end of the thin portion 25 with respect to the total length L2 of the body portion 20 is The ratio L6 / L2 of the distance L6 from directly below the support ring 14 to the upper end of the constricted portion 22 with respect to the total length L2 of the body portion 20 is 0.02 or more and 0.20 or less. And the weight is 17 g or less. In other words, the preform 10 has a total length L2 of the body portion 20 within a predetermined range, and can be reduced in weight by having the thin portion 25 and the constricted portion 22, and is compatible with the large diameter portion 21 and the thin portion 25. An easily stretchable region that is easily stretched is formed in a predetermined range from directly below the support ring 14 toward the bottom 24. Further, the preform 10 is a region corresponding to the constricted portion 22 and the thickness increasing portion 26, and a region is formed in which it is difficult to gradually stretch from the lower end of the easy stretch region toward the bottom portion 24 side. And when preform 10 is shape | molded in a bottle shape with a blow molding machine, it is designed so that the resin in the constriction part 22 may be effectively extended from directly under the support ring 14.

  The heated preform 10 is then formed into a plastic bottle, for example a PET bottle 100, by a blow molding machine. FIG. 5 is a cross-sectional view schematically showing the preform 10 and the PET bottle 100 after blow molding. A biaxial stretch blow molding apparatus 60 as an example of a blow molding machine includes a mold 61, a stretching rod 62, a high-pressure air supply device (not shown), and a control device (not shown) that controls them. In addition, although the downward blow molding method is illustrated in FIG. 5, the upward blow molding method in which the material is hardly affected by gravity may be used.

  The mold 61 has a shape corresponding to the PET bottle 100 to be formed. The mold 61 includes, for example, a body mold 61 a configured in half corresponding to the body part 130, and a bottom mold 61 b corresponding to the bottom part 140. The surface temperature of the mold 61 is appropriately set according to the use of the PET bottle 100, particularly the heat resistance. For example, the surface temperature of the body mold 61a is 20 ° C. to 130 ° C., and the bottom mold 61b. The surface temperature is controlled to 5 to 30 ° C.

  The extending rod 62 is configured to be extendable and contractable within the mold 61. And the extending | stretching rod 62 is comprised so that the trunk | drum 20 of the preform 10 by which the opening | mouth part 11 was attached to the metal mold | die 61, and the bottom part 24 may be extended | stretched in a vertical (axial) direction. The high-pressure air supply device is configured to blow out the high-pressure air A whose temperature has been adjusted. The high-pressure air A may be supplied to the inside of the preform 10 attached to the mold 61, may be blown out from the stretching rod 62, or may be blown out from a member different from the stretching rod 62. The high-pressure air A is configured to extend the body portion 20 of the preform 10 in the transverse (diameter) direction and lower the surface temperature of the body portion 20 after the stretching.

  The heated preform 10 is mounted on a mold 61 of a biaxial stretch blow molding apparatus 60. Thereafter, the body portion 20 and the bottom portion 24 of the preform 10 attached to the mold 61 are stretched in the longitudinal direction by the stretching rod 62. In this case, the longitudinal stretching ratio from the preform 10 to the PET bottle 100 is preferably 1.3 times or more and 3.6 times or less.

  Here, the longitudinal stretch ratio is the length from the upper end of the neck portion 110 of the PET bottle 100 to the lower end of the bottom portion 140 with respect to the length L2 (see FIG. 1) from the upper end of the body portion 20 of the preform 10 to the lower end of the bottom portion 24. This is the ratio of the length L3 (see FIGS. 5 and 6). The distance from the lower surface of the support ring 14 to the bottom wall 141 at the lower end of the bottom portion 140 is a length L3. The molecules of the preform 10 having an amorphous structure that is an aggregate of an amorphous part and a crystalline part undergo orientational crystallization by stretching, and as a result, the strength, rigidity, heat resistance, and the like of the PET bottle 100 are increased. . When the longitudinal draw ratio is less than 1.3 times, the molecular orientation of the PET bottle 100 (preform 10) does not increase, while when the longitudinal draw ratio is 3.6 times or more, the PET bottle 100 It becomes difficult to mold.

  Further, the body portion 20 of the preform 10 stretched in the longitudinal direction is stretched by the high-pressure air A in the lateral direction until it hits the mold 61. In this case, the transverse stretch ratio from the preform 10 to the PET bottle 100 is preferably 2.0 times or more and 4.1 times or less.

  Here, the transverse stretch ratio is the ratio of the outer diameter D5 of the body portion 130 of the PET bottle 100 to the outer diameter D4 (see FIGS. 1 and 2) of the small diameter portion 23 of the body portion 20 of the preform 10. The molecules of the preform 10 are similarly oriented and crystallized by stretching in the lateral direction. As a result, the strength, rigidity, heat resistance, and the like of the PET bottle 100 are increased. When the transverse draw ratio is less than 2.0, the molecular orientation of the PET bottle 100 (preform 10) does not increase. On the other hand, when the transverse draw ratio is 4.1 or more, the PET bottle 100 is molded. It becomes difficult.

  Thus, in the molding by the biaxial stretch blow molding apparatus 60, the stretching ratio in the longitudinal direction is 1.3 times or more and 3.6 times or less, and the stretching ratio in the transverse direction is 2.0 times or more and 4.1 times or less. According to the configuration of the biaxial stretch blow molding, it is possible to mold the PET bottle 100 reduced in weight from the preform 10 with better blow moldability.

  Here, the neck portion 110 to the shoulder portion 120 of the PET bottle 100 are formed by extending the resin in the constricted portion 22 in the longitudinal direction and the lateral direction from directly below the support ring 14 of the preform 10. Further, as described above, the preform 10 has an easily stretched region defined in a predetermined range corresponding to the large diameter portion 21 and the thin portion 25 formed immediately below the support ring 14. Therefore, when the preform 10 is stretched in the longitudinal direction, the resin corresponding to the large diameter portion 21 and the thin portion 25 which are the easy stretch regions is effectively stretched. Sufficient resin can be spread, and the PET bottle 100 reduced in weight by the favorable blow moldability from the preform 10 can be shape | molded.

  In addition, the full length L2 of the trunk | drum 20 of the preform 10 is 42 mm or more and 65 mm or less. As described above, since the weight of the preform 10 is 17 g or less, if the total length L2 of the body portion 20 is larger than 65 mm, the thickness T2 of the predetermined thickness portion 27 becomes too thin, and the blow moldability deteriorates. It is not preferable. On the other hand, if the total length L2 is smaller than 42 mm, the center of gravity of the preform 10 passes by the mouth 11 side. Although a detailed description is omitted, the preform 10 is a gripping device that grips a portion of the mouth 11 below the turnip 15 and a portion of the mouth 11 below the support ring 14 in the state shown in FIG. May be conveyed by. When transporting using such a gripping device, if the center of gravity of the preform 10 passes by the side of the mouth portion 11, the preform 10 is likely to fluctuate and may lie down and become clogged. Therefore, if the total length L2 is smaller than 42 mm, the transportability is undesirably lowered. Further, when the total length L2 is smaller than 42 mm, the length L3 from the upper end of the neck portion 110 to the lower end of the bottom portion 140 of the PET bottle 100 capable of good blow molding becomes short, and the versatility of the preform 10 is lowered. It is not preferable.

  Moreover, the range of the easy extension area | region corresponding to the large diameter part 21 and the thin part 25 is ratio L4 of distance L4 from just under the support ring 14 to the lower end of the thin part 25 with respect to the full length L2 of the trunk | drum 20, as mentioned above. / L2 is 0.02 or more and 0.25 or less, and the ratio L6 / L2 of the distance L6 from directly below the support ring 14 to the upper end of the constricted portion 22 with respect to the total length L2 of the trunk portion 20 is 0.02 or more, and. It is defined by being 20 or less. In addition, the balance between the range of the large diameter portion 21 and the range of the thin portion 25 is designed so that the stretching from the lower portion of the easy stretching region to the upper portion of the constricted portion 22 and the thickness increasing portion 26 is appropriate.

  When the ratio L4 / L2 is smaller than 0.02, the range of the thin portion 25 is narrowed, and the effect of reducing the weight of the PET bottle 100 (preform 10) is hardly exhibited. In addition, the range of the easy stretch region is narrowed, the shoulder portion 120 of the PET bottle 100 becomes thick, and sufficient resin does not reach the bottom portion 140 of the PET bottle 100, so that the bottom portion 140 becomes thin. Therefore, the blow moldability of the PET bottle 100 is undesirably lowered. On the other hand, when the ratio L4 / L2 is larger than 0.25, a portion corresponding to the thin portion 25 that becomes a narrow flow path space becomes long in the cavity 45 when the preform 10 is injection-molded. Therefore, the flow of the resin from the gate is deteriorated at a portion corresponding to the thin portion 25 of the cavity 45, and molding defects such as a short mold and a weld are likely to occur, and the injection moldability is deteriorated. Further, when the ratio L6 / L2 is smaller than 0.02, the range of the large diameter portion 21 as the easy stretch region is narrowed, the shoulder portion 120 of the PET bottle 100 becomes thick, and the bottom portion of the PET bottle 100 Insufficient resin reaches 140 and the bottom 140 becomes thin. Therefore, the blow moldability of the PET bottle 100 is undesirably lowered. On the other hand, if the ratio L6 / L2 is greater than 0.20, the range of the large diameter portion 21 as the easy stretch region becomes wide, the large diameter portion 21 is stretched too much, and the shoulder 120 of the PET bottle 100 is thin. become. Therefore, the blow moldability of the PET bottle 100 is undesirably lowered. Moreover, the range of the constriction part 22 and the small diameter part 23 becomes narrow, and it becomes difficult to exhibit the effect of weight reduction of the PET bottle 100 (preform 10). In addition, the inclination of the constricted portion 22 with respect to the vertical direction is increased, and when the preform 10 is injection molded, the flow of resin from the gate is deteriorated at a portion corresponding to the constricted portion 22 of the cavity 45, and the injection moldability is reduced. It is not preferable.

  From the viewpoint of improving the injection moldability of the preform 10 and the blow moldability when the PET bottle 100 reduced in weight from the preform 10 is molded, from directly below the support ring 14 with respect to the entire length L2 of the body portion 20. The ratio L7 / L2 of the distance L7 to the lower end of the constricted part 22 is preferably 0.10 or more and 0.40 or less. When the ratio L7 / L2 is smaller than 0.10, the inclination of the constricted portion 22 with respect to the vertical direction is increased, and the resin flow from the gate flows into the constricted portion 22 of the cavity 45 during the injection molding of the preform 10. It is unfavorable because it deteriorates at the corresponding part and the injection moldability is lowered. Moreover, it becomes difficult for the constricted part 22 to extend | stretch in a horizontal direction, and blow moldability falls, and is unpreferable. On the other hand, when the ratio L7 / L2 is larger than 0.40, the range of the small diameter portion 23 becomes narrow, and the effect of reducing the weight of the PET bottle 100 (preform 10) is hardly exhibited.

  In addition, the ratio L5 / L2 of the distance L5 from the position immediately below the support ring 14 to the lower end of the thickness increasing portion 26 with respect to the entire length L2 of the trunk portion 20 is preferably 0.10 or more and 0.32 or less. If the ratio L5 / L2 is smaller than 0.10, the range of the thickness increasing portion 26 is narrowed, so that the change in the thickness in the thickness increasing portion 26 becomes local, which is not preferable because the blow moldability is lowered. On the other hand, when the ratio L5 / L2 is greater than 0.32, the range of the predetermined thickness portion 27 is narrowed, and the thickness of the barrel portion 130 of the PET bottle 100 is likely to be biased when blow molding. .

  Moreover, it is preferable that ratio T1 / T2 of thickness T1 of the thin part 25 with respect to thickness T2 of the predetermined thickness part 27 is 0.60 or more and 0.85 or less. When the ratio T1 / T2 is smaller than 0.6, the thin portion 25 is not effectively stretched during blow molding, the shoulder portion 120 of the PET bottle 100 becomes thick, and the bottom portion of the PET bottle 100 Since 140 becomes thin, blow moldability is lowered, which is not preferable. Further, when the preform 10 is injection-molded, the flow of resin from the gate is deteriorated at a portion corresponding to the thin portion 25 of the cavity 45, which is not preferable because the injection moldability is lowered. Further, the thickness of the neck portion 110 of the PET bottle 100 becomes thin, and it becomes difficult to impart sufficient strength to the neck portion 110. On the other hand, when the ratio T1 / T2 is larger than 0.6, the effect of reducing the weight of the PET bottle 100 (preform 10) is hardly exhibited. Moreover, the thin part 25 as an easy extending | stretching area | region is not extended | stretched effectively, but it becomes easy to produce bias | deviation in the thickness of the shoulder part 120 and the bottom part 140 of the PET bottle 100. FIG.

  Moreover, it is preferable that ratio T3 / T1 of thickness T3 of the bottom center 28 with respect to thickness T1 of the thin part 25 is 1.01 or more and 1.30 or less. When the ratio T3 / T1 is smaller than 1.01, the bottom center 28 is not effectively stretched during blow molding, the shoulder 120 of the PET bottle 100 becomes thin, and the bottom 140 of the PET bottle 100 Becomes thick and blow moldability is lowered, which is not preferable. Further, when the preform 10 is injection-molded, the flow of resin from the gate is deteriorated at a portion corresponding to the bottom center 28 of the cavity 45, which is not preferable because the injection moldability is lowered. On the other hand, when the ratio T3 / T1 is greater than 1.30, the bottom center 28 is not effectively stretched during blow molding, and the thickness of the shoulder 120 and the bottom 140 of the PET bottle 100 is biased. It tends to occur. Further, the effect of reducing the weight of the PET bottle 100 (preform 10) is hardly exhibited.

Moreover, it is preferable that ratio D4 / D3 of the outer diameter D4 of the small diameter part 23 with respect to the outer diameter D3 of the large diameter part 21 is 0.60 or more and 0.90 or less. When the ratio D4 / D3 is smaller than 0.60, the inclination of the constricted portion 22 with respect to the vertical direction becomes large, and the resin flow from the gate corresponds to the constricted portion 22 of the cavity 45 during injection molding of the preform 10. This is unfavorable because it deteriorates at the site where the injection is performed and the injection moldability deteriorates. Moreover, it becomes difficult for the constricted part 22 to extend | stretch in a horizontal direction, and blow moldability falls, and is unpreferable. On the other hand, when the ratio D4 / D3 is larger than 0.90, the effect of reducing the weight of the PET bottle 100 (preform 10) is hardly exhibited.

  Further, it is preferable that the lower end of the thin portion 25 is positioned in the vicinity of the upper end portion in the constricted portion 22, and the lower end of the thickness increasing portion 26 is positioned in the vicinity of the lower end portion in the constricted portion 22. With such a configuration, the stretchability of the body portion 20 is drastically increased at the joint portion between the thin portion 25 and the thick portion 26 and the joint portion between the thick portion 26 and the predetermined thick portion 27. There is no change, and the blow moldability when molding the PET bottle 100 reduced in weight from the preform 10 can be improved. However, the arrangement of the thin portion 25 and the thickness increasing portion 26 with respect to the constricted portion 22 is not limited to the above-described configuration, and can be appropriately designed according to the form and weight of the PET bottle 100, for example, the thin portion The lower end of 25 may be located in the large diameter portion 21, and the lower end of the thickness increasing portion 26 may be located in the small diameter portion 23. Further, the lower end of the predetermined thick portion 27 may be located in the bottom portion 24. Further, the bottom 24 may be formed so as to have a uniform thickness, or may be formed so that the thickness gradually decreases from a position below the upper end of the bottom 24 to the center. However, from the viewpoint of effectively reducing the weight of the PET bottle 100 (preform 10), the bottom 24 is preferably formed so that the thickness gradually decreases from the lower end to the center of the small diameter portion 23.

  As described above, in the manufacturing method of the PET bottle 100 according to the present embodiment, the trunk portion 20 includes the large diameter portion 21, the constricted portion 22, the small diameter portion 23, and the bottom portion 24, and further, the thickness thereof is the smallest. A thin portion 25 having a uniform thickness; a thickness increasing portion 26 formed so that the thickness gradually increases; and a predetermined thickness portion 27 having a uniform thickness. 20 has a total length L2 of 42 mm or more and 65 mm or less, and a ratio L4 / L2 of a distance L4 from directly below the support ring 14 to the lower end of the thin portion 25 with respect to the total length L2 of the trunk portion 20 is 0.02 or more and 0.25 or less. The ratio L6 / L2 of the distance L6 from directly below the support ring 14 to the upper end of the constricted portion 22 with respect to the total length L2 of the body portion 20 is 0.02 or more and 0.20 or less, and the weight is 17 g or less. Reform 10 with injection molding device 4 In comprising a step of manufacturing, and a step of molding a bottle-shaped preform 10 by biaxial stretch blow molding apparatus 60. And by this manufacturing method, the PET bottle 100 reduced in weight by the favorable blow moldability from the preform 10 can be manufactured. At that time, it is not necessary to use a special manufacturing method.

  In addition, it is preferable that thickness T4 after shaping | molding of the trunk | drum 130 of PET bottle 100 is 0.05 mm or more and 0.18 mm or less. If the thickness of the trunk portion 130 is within this range, the PET bottle 100 reduced in weight with better blow moldability can be molded from the preform 10.

  Further, in the preform 10, the lower portion of the large diameter portion 21 and the constricted portion 22 may be molded so as to form a shoulder portion 120 having an inclination with respect to the horizontal direction in the PET bottle 100. preferable. By molding in this way, it is possible to mold the PET bottle 100 reduced in weight from the preform 10 with better blow moldability.

  In addition, in this embodiment, the use of the PET bottle 100 to be molded is not limited. Therefore, the PET bottle 100 may be molded so as to have pressure resistance, heat resistance, and the like. Furthermore, the filling method of the contents into the PET bottle 100 is not limited. Therefore, the PET bottle 100 may be used for hot filling or aseptic filling.

  As described above, in the PET bottle 100 according to this embodiment, the preform 10 is formed into a bottle shape by the biaxial stretch blow molding apparatus 60. And by using the biaxial stretch blow molding apparatus 60, the PET bottle 100 reduced in weight by favorable blow moldability can be effectively molded from the preform 10 according to the present embodiment.

  Next, the configuration of the PET bottle 100 formed from the preform 10 according to the present embodiment will be described in detail. FIG. 6 is a front view showing the PET bottle 100 formed from the preform 10 according to the present embodiment. The PET bottle 100 illustrated in FIG. 6 is a square bottle having a substantially square cross-sectional view in the horizontal direction. As described above, the PET bottle 100 has the mouth portion 11, the neck portion 110, the shoulder portion 120, the trunk portion 130, and the bottom portion 140. As described above, the configuration of the mouth portion 11 of the PET bottle 100 is the same as that of the mouth portion 11 of the preform 10.

  The upper side of the neck part 110 is connected to the lower surface of the support ring 14 of the mouth part 11, while the lower side is connected to the shoulder part 120. The neck part 110 has a cylindrical shape.

  The shoulder 120 is connected to the neck 110 on the upper side, and is connected to the trunk 130 on the lower side. The shoulder 120 has a substantially quadrangular pyramid shape that increases in diameter from the upper side to the lower side.

  The body portion 130 has a substantially regular rectangular tube shape as a whole by connecting four wall portions 131 having the same shape to each other in the circumferential (horizontal) direction. Each of the wall portions 131 includes a pressure absorbing panel 132, a plurality of horizontal grooves 133, vertical grooves 134, and the like. The uneven pressure absorbing panel 132 absorbs the pressure change by deforming itself when the internal pressure of the PET bottle 100 is changed to the decompression side, and particularly the load in the horizontal direction of the PET bottle 100. Has the function of maintaining the strength of the side wall, which is the strength to withstand. The lateral groove 133 also has a function of maintaining the side wall strength of the trunk portion 130. On the other hand, the longitudinal groove 134 has a function of improving the buckling strength, which is the strength that can withstand the load in the vertical direction of the body portion 130.

  The upper side of the bottom part 140 is connected to the lower side of the trunk part 130. The bottom 140 has a bottom wall 141, a dome 142, and the like. The substantially flat plate-shaped bottom wall 141 extends in a direction perpendicular to the body portion 130 and serves as a ground contact surface of the PET bottle 100. The dome 142 is configured to protrude from the bottom wall 141 to the inside (upward) of the PET bottle 100 on the inner periphery of the bottom wall 141, and has a function of improving the strength of the bottom portion 140. The configuration of the bottom 140 is not limited to the example shown in FIG. 6, and may be a shape corresponding to the contents, for example, a shape in which ribs are provided radially, or a so-called petaloid shape.

  The shape below the support ring 14 of the PET bottle 100 is not limited to the example shown in FIG. 6 and may be any shape as long as the preform 10 is formed by blow molding. For example, in this embodiment, the square bottle shown in FIG. 6 can be suitably formed. However, the plastic bottle formed in the present embodiment is not limited to a square bottle, and may be a round bottle. Furthermore, the shape where the width | variety of the trunk | drum 130 expands toward the downward direction may be sufficient. Further, the shape of the pressure absorbing panel 132, the lateral groove 133, and the longitudinal groove 134 formed in the body portion 130 can be freely designed.

  FIG. 7 is a front view showing another PET bottle 200 formed from the preform 10 according to the present embodiment. Similar to the square bottle PET bottle 100 described above, the PET bottle 200 has a mouth portion 11, a neck portion 210, a shoulder portion 220, a trunk portion 230, and a bottom portion 240. In the present embodiment, the round bottle shown in FIG. 7 can also be suitably formed.

  The PET bottle 100 and the PET bottle 200 (hereinafter simply referred to as the PET bottle 100) molded in this way, the contents filled in the PET bottle 100, and the PET bottle filled with the contents The filler is constituted by a cap that seals 100.

  The PET bottle 100 according to the present embodiment is not limited by size, and can be applied to various sizes. For example, the volume of the PET bottle 100 may be 100 ml to 2000 ml, and is particularly suitable for the PET bottle 100 having a volume of 200 ml to 600 ml. In particular, the overall height of the PET bottle 100 is preferably 100 mm to 250 mm, and the outer diameter D5 of the body portion 130 is preferably 40 mm to 80 mm. Thus, the effects exhibited by the PET bottle 100 according to the present embodiment can be suitably obtained.

  In the above description, an example in which PET is used as a particularly suitable material for the preform 10 according to the present embodiment has been shown. However, in the present embodiment, any material having suitability for blow molding may be used. Therefore, it is preferable to use a thermoplastic resin as the material of the PET bottle 100 according to this embodiment.

  As the thermoplastic resin constituting the PET bottle 100, in addition to polyethylene terephthalate, for example, thermoplastic polyester such as polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyarylate, or a copolymer thereof, these resins, Alternatively, blends with other resins are suitable, and in particular, ethylene terephthalate-based thermoplastic polyesters such as polyethylene terephthalate can be suitably used. Furthermore, acrylonitrile resin, polyethylene, polypropylene, propylene-ethylene copolymer and the like can also be used. Furthermore, it is also possible to use plant-derived biomass plastics such as polylactic acid (PLA).

  Various additives such as colorants, UV absorbers, mold release agents, lubricants, nucleating agents, antioxidants, antistatic agents, etc. are blended with the above-mentioned resins within a range that does not impair the quality of the molded product. can do. The PET bottle 100 is preferably sterilized by adding hydrogen peroxide and peracetic acid.

  As the ethylene terephthalate thermoplastic resin constituting the PET bottle 100, most of the ester repeating portion, generally 70 mol% or more, is occupied by ethylene terephthalate units, and the glass transition point (Tg) is 50 to 90 ° C. Yes, those having a melting point (Tm) in the range of 200 to 275 ° C are suitable. In addition, as an ethylene terephthalate thermoplastic polyester, polyethylene terephthalate is particularly excellent in terms of pressure resistance, but in addition to the ethylene terephthalate unit, dibasic acids such as isophthalic acid and naphthalenedicarboxylic acid, and propylene glycol Copolyesters containing a small amount of ester units composed of diols such as can also be used.

  Furthermore, the PET bottle 100 can be composed of two or more thermoplastic polyester layers. Furthermore, when the PET bottle 100 is constituted by two or more thermoplastic polyester layers, an intermediate layer such as a barrier layer or an oxygen absorbing layer can be provided between the layers. As the oxygen absorbing layer, a layer containing a combination of an oxidizable organic component and a transition metal catalyst, or a gas barrier resin that does not substantially oxidize can be used.

  The preform 10 according to the present embodiment has an appropriate strength and plastic deformability according to the configuration made of plastic, particularly PET, and can be effectively molded with a highly versatile material. Plastics, particularly PET, can be easily molded as a PET bottle 100, and the PET bottle 100 can be manufactured with a highly versatile apparatus.

  As described above, the preform 10 according to the present embodiment has a bottomed tube including the mouth portion 11 having the support ring 14 at the lower end and the body portion 20 connected to the lower end of the support ring 14. The body portion 20 has a large-diameter portion 21 that is continuous with the lower end of the support ring 14, a constricted portion 22 that is continuous with the lower end of the large-diameter portion 21, and is reduced in diameter downward, and a constricted portion 22 has a small-diameter portion 23 connected to the lower end of the small-diameter portion 22 and a bottom portion 24 connected to the lower end of the small-diameter portion 23, and the body portion 20 has portions with different thicknesses. A thin portion 25 in which the minimum thickness is uniformly formed downward, a thickness increase portion 26 formed so that the thickness gradually increases downward from the lower end of the thin portion 25, and an increase in thickness The predetermined thickness part 2 in which the thickness is uniformly formed downward from the lower end of the part 26 The overall length L2 of the body portion 20 is 42 mm or more and 65 mm or less, and the ratio L4 / L2 of the distance L4 from directly below the support ring 14 to the lower end of the thin portion 25 with respect to the overall length L2 of the body portion 20 is 0. The ratio L6 / L2 of the distance L6 from directly below the support ring 14 to the upper end of the constricted portion 22 with respect to the total length L2 of the body portion 20 is 0.02 or more and 0.20 or less. The weight is configured to be 17 g or less. And according to the structure which concerns on this embodiment, the blow moldability at the time of a lightweight bottle being shape | molded with the biaxial stretch blow molding apparatus 60 from the preform 10 can be made favorable.

  Hereinafter, the present disclosure will be described in more detail and specifically with reference to examples. However, the present disclosure is not limited to the following examples.

<Materials and methods>
[Example 1]
The injection molding apparatus 40 was used, and the preform 10 according to this embodiment shown in FIGS. 1 and 2 was produced. That is, the preform 10 has a bottomed cylindrical shape including a mouth portion 11 having a support ring 14 at the lower end and a body portion 20 provided continuously to the lower end of the support ring 14, and the body portion 20 has a large diameter portion. 21, a constricted portion 22 whose diameter is reduced downward, a small diameter portion 23, and a bottom portion 24. Further, the preform 10 includes a thin portion 25 in which the body portion 20 has portions with different thicknesses, and a minimum thickness is uniformly formed downward from the lower end of the support ring 14. A thickness increasing portion 26 formed so that the thickness gradually increases from the lower end downward, and a predetermined thickness portion 27 formed uniformly from the lower end of the thickness increasing portion 26 downward; The overall length L2 of the body portion 20 is 42 mm or more and 65 mm or less, and the ratio L4 / L2 of the distance L4 from directly below the support ring 14 to the lower end of the thin portion 25 with respect to the overall length L2 of the body portion 20 is 0.02. The ratio L6 / L2 of the distance L6 from directly below the support ring 14 to the upper end of the constricted portion 22 with respect to the total length L2 of the body portion 20 is 0.02 or more and 0.20 or less, and is 0.25 or less. Has a characteristic of less than 17g . Preform 10 was made of polyethylene terephthalate and weighed 17 g. Further, the preform 10 has a thickness T1 of the thin portion 25 of 2.0 mm, a thickness T2 of the predetermined thickness portion 27 of 2.7 mm, a thickness T3 of the bottom center 28 of 2.2 mm, and the overall length of the trunk portion 20. L2 is 59 mm, the distance L4 from just below the support ring 14 to the lower end of the thin portion 25 is 5.0 mm, the distance L6 from just below the support ring 14 to the upper end of the constricted portion 22 is 5.0 mm, and outside the large diameter portion 21 The diameter D3 was 26 mm, and the outer diameter D4 of the small diameter portion 23 was 17 mm. The ratio L4 / L2 of the distance L4 from directly below the support ring 14 to the lower end of the thin portion 25 with respect to the entire length L2 of the body portion 20 is 0.08, and the necking is performed immediately below the support ring 14 with respect to the entire length L2 of the body portion 20. The ratio L6 / L2 of the distance L6 to the upper end of the portion 22 was 0.08. In addition, shaping defects did not occur during injection molding. A heating device 50 and a biaxial stretch blow molding device 60 were used, and the preform 10 was blow molded to produce the PET bottle 100 shown in FIG. The capacity of the produced PET bottle 100 was 500 ml. In addition, shaping defects did not occur during blow molding.

[Comparative Example 1]
An injection molding apparatus 40 is used, and in the preform 10 shown in FIGS. 1 and 2, the thicknesses of the large diameter portion 21, the constricted portion 22, and the small diameter portion 23 of the trunk portion 20 are substantially the same at any part. A preform as Comparative Example 1 was produced. That is, the preform of Comparative Example 1 does not have the thin portion 25 and the thickened portion 26 in the preform 10 shown in FIGS. 1 and 2. The bottom 24 gradually decreases in thickness from the lower end of the small diameter portion 23 to the center. The preform of Comparative Example 1 was made of polyethylene terephthalate and weighed 19 g. Further, the preform of Comparative Example 1 has a large diameter portion 21, a constricted portion 22 and a small diameter portion 23 having a thickness of 2.7 mm, a bottom center 28 having a thickness T3 of 2.2 mm, and a trunk portion 20 having a total length L2 of 59 mm. The distance L6 from directly below the support ring 14 to the upper end of the constricted portion 22 was 5.0 mm, the outer diameter D3 of the large diameter portion 21 was 26 mm, and the outer diameter D4 of the small diameter portion 23 was 17 mm. In addition, shaping defects did not occur during injection molding. A heating device 50 and a biaxial stretch blow molding device 60 were used, and the preform of Comparative Example 1 was blow molded to produce a bottle having the shape of a PET bottle 100. The capacity of the produced PET bottle was 500 ml. In addition, the shaping defect which whitening generate | occur | produced when the bottom part became thin at the time of blow molding generate | occur | produced.

[Comparative Example 2]
An injection molding apparatus 40 was used, and in the preform in Comparative Example 1, a preform as Comparative Example 2 in which the outer diameter D4 of the small diameter portion 23 was small was produced. The preform of Comparative Example 2 has a weight of 17 g, a large diameter portion 21, a constricted portion 22, a small diameter portion 23 having a thickness of 2.7 mm, a bottom center 28 having a thickness T3 of 2.2 mm, and a total length L2 of the trunk portion 20. 59 mm, the distance L6 from just below the support ring 14 to the upper end of the constricted portion 22 was 5.0 mm, the outer diameter D3 of the large diameter portion 21 was 26 mm, and the outer diameter D4 of the small diameter portion 23 was 13 mm. In addition, the molding defect which a weld occurs in the mouth part 11 at the time of injection molding occurred.

[Comparative Example 3]
An injection molding apparatus 40 was used, and a preform 310 having a mouth 311 and a body 320 shown in FIG. Here, FIG. 8 is a cross-sectional view of a preform 310 similar to FIG. The preform 310 of Comparative Example 3 has a configuration that does not have the constricted portion 22 in the preform 10 shown in FIGS. 1 and 2, and the body portion 320 has an outer diameter formed in a small cylinder, and has a mouth portion. Reference numeral 311 denotes a configuration similar to that of the mouth portion 11 of the preform 10. On the other hand, the body portion 320 of the preform 310 of the comparative example 3 has a portion having a different thickness similarly to the preform 10 and has a minimum thickness from the lower end of the support ring 314 of the mouth portion 311 downward. Are formed uniformly, a thickened portion 326 formed so that the thickness gradually increases downward from the lower end of the thinned portion 325, and downward from the lower end of the thickened portion 326. And a predetermined thickness portion 327 having a uniform thickness. Further, the bottom 324 is formed so that the thickness gradually decreases from the upper end to the center.

  The preform 310 of Comparative Example 3 was made of polyethylene terephthalate and weighed 20 g. Further, the preform 310 of Comparative Example 3 has a thickness T31 of the thin portion 325 of 2.0 mm, a thickness T32 of the predetermined thickness portion 327 of 2.7 mm, a thickness T33 of the bottom center 328 of 2.2 mm, The total length L32 of the part 320 was 59 mm, the distance L34 from just below the support ring 314 to the lower end of the thin part 325 was 3.0 mm, and the outer diameter D33 of the body part 320 was 26 mm. In addition, shaping defects did not occur during injection molding. The heating device 50 and the biaxial stretch blow molding device 60 were used, and the preform 310 of Comparative Example 3 was blow molded to produce a bottle having the shape of the PET bottle 100. The capacity of the produced PET bottle was 500 ml. In addition, the shaping defect which whitening generate | occur | produced when the bottom part became thin at the time of blow molding generate | occur | produced.

[Comparative Example 4]
The injection molding apparatus 40 was used, and in the preform 310 in the comparative example 3, a preform as the comparative example 4 having a long distance L34 from just below the support ring 314 to the lower end of the thin portion 325 was produced. The preform of Comparative Example 4 has a weight of 17 g, a thickness T31 of the thin portion 325 of 2.0 mm, a thickness T32 of the predetermined thickness portion 327 of 2.7 mm, a thickness T33 of the bottom center 328 of 2.2 mm, The overall length L32 of the body part 320 was 59 mm, the distance L34 from just below the support ring 314 to the lower end of the thin part 325 was 24 mm, and the outer diameter D33 of the body part 320 was 26 mm. In addition, the molding defect which a weld occurs in the mouth part 311 at the time of injection molding occurred.

[Comparative Example 5]
An injection molding apparatus 40 is used, and in the preform 10 shown in FIGS. 1 and 2, the ratio L4 / L2 of the distance L4 from the position immediately below the support ring 14 to the lower end of the thin portion 25 with respect to the total length L2 of the trunk portion 20 is A preform as Comparative Example 5 was produced, in which the ratio L6 / L2 of the distance L6 from the position immediately below the support ring 14 to the upper end of the constricted portion 22 with respect to the total length L2 of the trunk portion 20 was 0.01. . The preform of Comparative Example 5 has a weight of 17 g, a thickness T1 of the thin portion 25 of 2.0 mm, a thickness T2 of the predetermined thickness portion 27 of 2.7 mm, and a thickness T3 of the bottom center 28 of 2.2 mm. The entire length L2 of the body 20 is 59 mm, the distance L4 from directly below the support ring 14 to the lower end of the thin portion 25 is 0.6 mm, and the distance L6 from directly below the support ring 14 to the upper end of the constricted portion 22 is 17.7 mm, large. The outer diameter D3 of the diameter portion 21 was 26 mm, and the outer diameter D4 of the small diameter portion 23 was 17 mm. In addition, shaping defects did not occur during injection molding. The bottle of the shape of the PET bottle 100 was produced by blow-molding the preform of the comparative example 5 using the heating device 50 and the biaxial stretch blow molding device 60. The capacity of the produced PET bottle was 500 ml. In addition, the shaping defect which whitening generate | occur | produced when the bottom part became thin at the time of blow molding generate | occur | produced.

<Result>
(Lightweight evaluation)
Each of the preforms 10 and 310 of Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 3, Comparative Example 4, and Comparative Example 5 was evaluated for weight reduction. Table 1 shows the results of the evaluation of the weight reduction of each of the preforms 10 and 310, and is indicated by ◯: 17 g or less and x: greater than 17 g.

(Injection molding evaluation)
The injection moldability of each of the preforms 10 and 310 of Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, and Comparative Example 5 was evaluated. Table 1 shows the results of visual evaluation of the preforms 10 and 310 produced by injection molding, and is indicated by ◯: no shaping failure and x: occurrence of shaping failure.

(Blow molding evaluation)
Blow moldability was evaluated for each of the preforms 10 and 310 of Example 1, Comparative Example 1, Comparative Example 3, and Comparative Example 5 in which no shaping failure occurred during injection molding. Table 1 shows the results of visual evaluation of the bottles produced from each of the preforms 10 and 210 by blow molding, ○: no shaping failure, x: shaping failure occurred,-: not implemented, It is written by.

(Comprehensive evaluation)
Based on the weight reduction evaluation, injection molding evaluation, and blow molding evaluation described above, each preform 10 of Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, and Comparative Example 5, and A total rating of 310 was made. Table 1 shows the results of comprehensive evaluation. Comprehensive evaluation is described by (circle): favorable and x: no aptitude.

  The following points were derived from the examples described above. As shown in Table 1, in Example 1, weight reduction was realized, and injection moldability and blow moldability were good. Although Comparative Example 1 had injection moldability, weight reduction was not realized, and a shaping defect occurred at the bottom of the PET bottle during blow molding. In Comparative Example 2, the weight of the small-diameter portion was extremely reduced in order to achieve weight reduction, that is, the outer diameter of the small-diameter portion was extremely small, so that a molding defect occurred during injection molding. Although the comparative example 3 had injection moldability, weight reduction was not implement | achieved and the shaping defect generate | occur | produced in the bottom part of PET bottle at the time of blow molding. In Comparative Example 4, since the weight of the body portion was extremely reduced in order to achieve weight reduction, that is, the range of the thin portion was extremely widened, a molding defect occurred during injection molding. In Comparative Example 5, the range of the large diameter portion was not appropriate with respect to the entire length of the body portion, and a shaping defect occurred at the bottom of the PET bottle during blow molding.

  From the results of the above examples, the preform 10 according to the present embodiment has good injection moldability and good blow moldability when a lightweight bottle is molded by a blow molding machine. Indicated.

  The present disclosure can be suitably used for various containers filled with liquid as contents. However, the present disclosure is not limited to the above-described embodiments. The container of the present disclosure includes, for example, various non-carbonated beverages such as green tea, oolong tea, black tea, coffee, fruit juice, and soft drinks, carbonated beverages, or seasonings such as soy sauce, sauce, mirin, edible oil, and alcoholic beverages. It is useful for all kinds of containers containing foods, etc., detergents, shampoos, cosmetics, pharmaceuticals, etc., and is suitable for sales by vending machines because the shape of the container is not limited. Furthermore, the contents can be used not only for liquids but also for containers filled with powder.

DESCRIPTION OF SYMBOLS 10 Preform 11 Mouth part 20 Body part 21 Large diameter part 22 Constriction part 23 Small diameter part 24 Bottom part 25 Thin part 26 Thickness increase part 27 Predetermined thick part 28 Bottom center 100, 200 PET bottle (plastic bottle)
D3 Outer diameter of the large diameter portion D4 Outer diameter of the small diameter portion L2 Overall length L4 of the trunk portion L4 Distance from just below the support ring to the lower end of the thin portion L5 Distance from just below the support ring to the lower end of the thickened portion L6 Distance L7 from the bottom to the top of the constricted portion Distance L1 from the bottom of the support ring to the bottom of the constricted portion T1 Thickness of the thin portion T2 Thickness of the predetermined thick portion T3 Thickness of the bottom center

Claims (14)

In a bottomed cylindrical preform comprising a mouth part having a support ring at the lower end and a body part connected to the lower end of the support ring,
The trunk is
A large diameter portion connected to the lower end of the support ring;
A constricted portion continuously provided at the lower end of the large-diameter portion and reducing in diameter downward;
A small diameter portion connected to the lower end of the constricted portion;
And a bottom portion continuously provided at the lower end of the small diameter portion,
The barrel has portions with different thicknesses,
A thin portion in which the minimum thickness is uniformly formed downward from the lower end of the support ring; and
A thickness increasing portion formed so that the thickness gradually increases from the lower end of the thin portion downward,
A predetermined thickness portion having a uniform thickness formed downward from the lower end of the thickness increase portion,
The overall length L2 of the trunk is 42 mm or more and 65 mm or less,
The ratio of the distance from directly below the support ring to the lower end of the thin portion with respect to the total length of the body portion is 0.02 or more and 0.25 or less,
The ratio of the distance from directly below the support ring to the upper end of the constricted part with respect to the total length of the trunk part is 0.02 or more and 0.20 or less,
A preform having a weight of 17 g or less. The ratio of the distance from directly below the support ring to the lower end of the constricted part with respect to the total length of the trunk part is 0.10 or more and 0.40 or less,
The preform according to claim 1. The ratio of the distance from directly below the support ring to the lower end of the thickness increasing portion with respect to the total length of the body portion is 0.10 or more and 0.32 or less,
The preform according to claim 1 or 2. The ratio of the thickness of the thin portion to the thickness of the predetermined thickness portion is 0.60 or more and 0.85 or less,
The preform according to any one of claims 1 to 3. The ratio of the outer diameter of the small diameter portion to the outer diameter of the large diameter portion is 0.60 or more and 0.90 or less,
The preform according to any one of claims 1 to 4. The bottom part is formed so that the thickness gradually decreases from the lower end of the small diameter part to the center of the bottom part,
The preform according to any one of claims 1 to 5. The ratio of the thickness of the bottom center to the thickness of the thin portion is 1.01 or more and 1.30 or less,
The preform according to claim 6. The lower end of the thin portion is located in the constricted portion,
The preform according to any one of claims 1 to 7. The lower end of the thickness increasing part is located in the constricted part,
The preform according to any one of claims 1 to 8.   A plastic bottle, wherein the preform according to any one of claims 1 to 9 is formed into a bottle shape by a blow molding machine. Molding by the blow molding machine is biaxial stretch blow molding in which the stretching ratio in the longitudinal direction is 1.3 times or more and 3.6 times or less, and the stretching ratio in the transverse direction is 2.0 times or more and 4.1 times or less. It is characterized by being,
The plastic bottle according to claim 10. The thickness of the body after molding is 0.05 mm or more and 0.18 mm or less,
The plastic bottle according to claim 10 or 11. The lower portion of the large-diameter portion and the constricted portion form a shoulder portion that is inclined with respect to the horizontal direction,
The plastic bottle according to any one of claims 10 to 12. A mouth portion having a support ring at a lower end; and a body portion continuously provided at a lower end of the support ring, wherein the body portion includes a large diameter portion provided continuously at a lower end of the support ring; and the large diameter portion. A constricted portion that is continuously provided at the lower end of the constricted portion and is reduced in diameter downward, a small diameter portion that is provided continuously at the lower end of the constricted portion, and a bottom portion that is provided continuously at the lower end of the small diameter portion, The portion has portions with different thicknesses, and a thin portion in which a minimum thickness is uniformly formed downward from the lower end of the support ring, and a thickness gradually decreases from the lower end of the thin portion downward. And a predetermined thickness portion formed uniformly from the lower end of the thickness increase portion downward, and the overall length L2 of the trunk portion is 42 mm. Or more, 65 mm or less, and from directly below the support ring with respect to the full length of the trunk portion, The ratio of the distance to the lower end of the thin part is 0.02 or more and 0.25 or less, and the ratio of the distance from directly below the support ring to the upper end of the constricted part with respect to the total length of the trunk part is 0.02 or more, Producing a preform with an injection molding machine having a weight of 0.20 or less and a weight of 17 g or less;
And a step of forming the preform into a bottle shape with a blow molding machine.

Images