Resin container manufacturing device, resin container manufacturing method, and mold

Abstract

To provide a resin container which can be manufactured by using the stretch blow molding method and which has large eccentricity, to provide a manufacturing method for a resin container, to provide a manufacturing device for a resin container, and to provide a mold.SOLUTION: A resin container (10) includes: a neck part (12) where an entrance part (11) of a content is formed; a side surface part connected to the neck part; and a bottom part (14) arranged on the opposite side from the neck part, and connected to the side surface part. The resin container is manufactured by the stretch blow molding method. At the bottom part, an overhang part (25) is formed protruding vertically downward. The overhang part 25 is positioned in an eccentric region (S2) out of a region (S1) projected vertically from an opening surface of the entrance part (11) of the neck part, out of the bottom part.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present disclosure relates to a resin container, a method for manufacturing a resin container, an apparatus for manufacturing a resin container, and a mold. [Background technology]

[0002] Patent Documents 1 to 5 disclose methods for manufacturing eccentric containers or containers with curved necks using a stretch blow molding method. For example, Patent Document 4 discloses a synthetic resin bottle-shaped container made by biaxial stretch blow molding, which has at least two axes, with the center of the opening of the mouth and the center of the bottom surface of the base being eccentric. Patent Document 5 discloses a blow-molded container made by a blow molding method using hydraulic pressure as the pressurizing medium, in which the central axis of the body is eccentric with respect to the central axis of the mouth. Patent Document 6 discloses a method for manufacturing a curved container using a direct blow molding method, in which the central axes of the neck and bottom are different. Patent Document 7 discloses a method for molding a container with a curved neck for holding liquid detergent, etc. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2006-062110 [Patent Document 2] Japanese Patent Application Publication No. 2009-241429 [Patent Document 3] Japanese Patent Publication No. 2003-181907 [Patent Document 4] Japanese Patent Publication No. 2012-006317 [Patent Document 5] Japanese Patent Publication No. 2003-040233 [Patent Document 6] International Publication No. 2016 / 017059 [Patent Document 7] Japanese Patent Publication No. 08-207128 Summary of the Invention [Problem to be solved by the invention]

[0004] As mentioned above, there are eccentric containers (off-center bottles) in which the central axis of the neck is not coaxial with the central axis of the body. Methods for manufacturing such eccentric containers include direct blow molding and stretch blow molding. Conventionally, stretch blow molding has been unable to manufacture containers with a large degree of eccentricity (the degree to which the central axis of the container neck is off-center relative to the central axis of the container body or the central axis of the container bottom). While direct blow molding can produce containers with a larger degree of eccentricity than stretch blow molding, it is inferior in terms of aesthetic appearance and dimensional accuracy. Furthermore, direct blow molding requires post-processing, such as removing any burrs remaining on the container after blow molding and trimming the removed surfaces. Another problem is the large amount of resin wasted (discarded). Against this background, there has been a growing demand in recent years for the stretch blow molding method to manufacture containers with a large degree of eccentricity.

[0005] The present disclosure aims to provide a resin container with a large degree of eccentricity that can be manufactured using a stretch blow molding method, a method for manufacturing a resin container, an apparatus for manufacturing a resin container, and a mold. [Means for solving the problem]

[0006] A resin container according to one aspect of the present disclosure that can solve the above problems comprises: Manufactured using the stretch blow molding method, a neck portion formed with an entrance / exit portion for contents; a side portion connected to the neck portion; a bottom portion disposed opposite the neck portion and connected to the side portion; Equipped with The bottom portion has a protruding portion that protrudes vertically downward, The protruding portion is located in an eccentric area of ​​the bottom portion that is out of the area projected perpendicularly from the opening plane of the entrance / exit portion of the neck portion.

[0007] According to the above configuration, the resin container has a protruding portion that protrudes vertically downward. In this manner, the resin container has a protruding portion formed on the bottom, and the resin container is so eccentric that the protruding portion is located in an eccentric region of the bottom that is outside the region vertically projected from the opening plane of the entrance / exit portion of the neck.

[0008] Furthermore, a resin container according to one embodiment of the present disclosure includes: Manufactured using the stretch blow molding method, a neck portion formed with an entrance / exit portion for contents; a side portion connected to the neck portion; a bottom portion disposed opposite the neck portion and connected to the side portion; Equipped with A cut-out remnant is formed on the bottom portion by cutting off a protruding portion that protrudes vertically downward, The cut-out remnant is located in an eccentric area of ​​the bottom that is out of the area projected perpendicularly from the opening plane of the entrance / exit section of the neck.

[0009] The resin container according to the above configuration is so eccentric that the excision residue is located in the eccentric region.

[0010] Furthermore, an apparatus for manufacturing a resin container according to one aspect of the present disclosure includes: a clamping mechanism that is provided independently of the bottom mold of the blow molding mold and that is capable of gripping a protrusion that is provided independently of a gate portion on the bottom of a preform accommodated in the blow molding mold when the split molds of the blow molding mold are open; a moving mechanism that moves the clamping mechanism so that, while the neck of the preform is held, the protrusion is positioned outside an area of ​​the bottom that is vertically projected from an opening plane of the entrance / exit portion of the neck; a stretching mechanism that closes the split mold and stretches the preform using a pressurizing medium; It has.

[0011] According to the above configuration, after the clamping mechanism grips the protrusion on the bottom of the preform, the preform is bent so that the protrusion moves to the outside of the area of ​​the bottom that is projected vertically from the opening surface of the entrance / exit section of the neck. The bent preform is then stretch-blown to produce a resin container with a large degree of eccentricity.

[0012] A method for manufacturing a resin container according to one embodiment of the present disclosure includes the steps of: a clamping step of gripping a protrusion provided independently of a gate portion on a bottom of a preform accommodated in the blow molding mold with a clamping mechanism provided independently on a bottom mold of the blow molding mold while the split molds of the blow molding mold are open; a bending step of bending the preform by moving the protrusion to the outside of a region of the bottom that is vertically projected from an opening surface of the inlet / outlet portion of the neck while the neck of the preform is held; a blowing step in which the split mold is closed and the preform is stretched by a pressurizing medium; It has.

[0013] According to the manufacturing method having the above-described configuration, after the clamping mechanism grips the protrusion on the bottom of the preform, the preform is bent so that the protrusion moves to the outside of the area of ​​the bottom that is projected vertically from the opening surface of the entrance / exit section of the neck. The bent preform is stretch-blown to produce a resin container with a large degree of eccentricity.

[0014] Furthermore, a mold according to one aspect of the present disclosure includes: A blow molding mold including a bottom mold, a holding mechanism, a clamping mechanism, and a moving mechanism, the holding mechanism is configured to be able to hold a neck portion of the preform, the clamping mechanism is provided independently on the bottom mold and is configured to be able to grip a protrusion provided independently of a gate portion on the bottom of the preform, The moving mechanism is configured to move the clamping mechanism and the bottom mold so that, while the neck of the preform is held, the protrusion is positioned outside the area of ​​the bottom projected vertically from the opening surface of the entrance / exit portion of the neck.

[0015] According to the above configuration, after the clamping mechanism grips the protrusion on the bottom of the preform, the preform is bent so that the protrusion moves to the outside of a projected area of ​​the bottom that extends perpendicularly from the opening surface of the entrance / exit section of the neck. The bent preform is then stretch-blown to produce a resin container with a large degree of eccentricity. [Effects of the Invention]

[0016] According to the present disclosure, it is possible to provide a resin container with a large degree of eccentricity that can be manufactured using a stretch blow molding method, a method for manufacturing a resin container, an apparatus for manufacturing a resin container, and a mold. [Brief explanation of the drawings]

[0017] [Figure 1A] FIG. 1A is a front view of a resin container with a large degree of eccentricity. [Figure 1B] FIG. 1B is a right side view of a resin container with a large degree of eccentricity. [Figure 1C] FIG. 1C is a bottom view of a resin container with a large degree of eccentricity. [Figure 2] FIG. 2 is a functional block diagram of the blow molding device. [Figure 3A] FIG. 3A is a diagram illustrating the appearance of the preform, and is a front view of the preform. [Figure 3B] FIG. 3B is a right side view illustrating the appearance of the preform. [Figure 3C] FIG. 3C is a diagram illustrating the appearance of the preform, and is a partially enlarged front view of the preform. [Figure 3D] FIG. 3D is a diagram illustrating the appearance of the preform, and is a partially enlarged right side view of the preform. [Figure 4A] FIG. 4A is a front view of a blow molding die. [Figure 4B] FIG. 4B is a right side view of the blow mold. [Figure 5] FIG. 5 is a diagram illustrating the clamping mechanism. [Figure 6A] FIG. 6A is a diagram illustrating the blow molding process, showing an example of a state in which a preform is housed in a mold with the split molds closed. [Figure 6B] FIG. 6B is a diagram illustrating the blow molding process, showing a state in which the protruding portion of the preform is gripped by a clamping mechanism. [Figure 6C] FIG. 6C is a diagram illustrating the blow molding process, showing the preform in a bent state. [Figure 7] FIG. 7 is a diagram showing an example of a conventional blow molding device. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that, for the sake of convenience of explanation, the dimensions of each component shown in the drawings may differ from the actual dimensions of each component.

[0019] In addition, for the sake of convenience, the description of this embodiment will refer to the "left-right direction," "front-rear direction," and "up-down direction" as appropriate. These directions are commonly defined in each figure. These directions are displayed for the sake of convenience and are not intended to be limited to the directions shown. Here, the "up-down direction" includes the "upward direction" and the "downward direction." The "front-rear direction" includes the "forward direction" and the "rearward direction." The "left-right direction" includes the "leftward direction" and the "rightward direction." For example, the directions in FIG. 1A are the directions when the container 10 is observed from the front outside when the container 10 is upright. However, the definition of the directions is not limited to this. The front-rear direction in FIG. 2 corresponds to the longitudinal direction of the blow molding apparatus 100.

[0020] First, referring to FIGS. 1A to 1C, a resin container 10 with large eccentricity according to this embodiment (hereinafter simply referred to as "container 10") will be described. FIG. 1A is a front view of resin container 10 with large eccentricity. FIG. 1B is a right side view of resin container 10. FIG. 1C is a bottom view of resin container 10. As illustrated in FIG. 1A, container 10 is a resin container comprising: a neck portion 12 having an inlet / outlet portion 11 located at the uppermost end; a body portion (side portion) 13 formed so as to be continuous with neck portion 12 and defining the side wall portion of container 10; and a bottom portion 14 formed so as to be continuous with body portion 13 and located at the lowermost end. Inlet / outlet portion 11 has an opening surface (top surface). Bottom portion 14 is located on the opposite side of neck portion 12 in the up-down direction. Bottom portion 14 comprises a protruding portion 25, which will be described later. Protruding portion 25 comprises a gate portion 26 and a protrusion 27. The synthetic resin material is a thermoplastic resin and can be appropriately selected depending on the application. Examples of synthetic resins include PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PCTA (polycyclohexanedimethylene terephthalate), Tritan (Tritan (registered trademark): a copolyester manufactured by Eastman Chemical Co.), PP (polypropylene), PE (polyethylene), PC (polycarbonate), PES (polyethersulfone), PPSU (polyphenylsulfone), PS (polystyrene), COP / COC (cyclic olefin polymer), PMMA (polymethyl methacrylate: acrylic), and PLA (polylactic acid).

[0021] In this embodiment, the area of ​​the bottom 14 formed when projected vertically from the opening surface of the entrance / exit portion 11 is referred to as the projection area S1. The projection area S1 is a region of the bottom 14 defined by two parallel lines extending downward from the lower end of the inner circumferential surface of the entrance / exit portion 11 in a vertical cross section. The protruding portion 25 is located in an area S2 outside the projection area S1. This area S2 is referred to herein as the "eccentric area S2." As illustrated in FIG. 1C , the eccentric area S2 is located approximately in the center and to the left of the bottom 14 of the container 10 (outside the projection area S1 and to the left of the projection area S1). In the container 10 according to this embodiment, the protruding portion 25 is provided in the center of the bottom 14. This center area extends over a predetermined distance (approximately several tens of millimeters) from the center point of the bottom 14 and is located approximately in the center of the area recessed upward of the bottom 14.

[0022] As illustrated in FIG. 1A , the center of the opening surface of the inlet / outlet portion 11 of the neck portion 12 (the diameter of the inlet / outlet portion 11) is defined as a first point CR1, and the intersection of a vertical line passing through the center of the overhanging portion 25 and the contact surface of the bottom portion 14 (a horizontal line defining the outer diameter of the lowest end of the bottom portion 14) is defined as a second point CR2. Furthermore, a line passing through the first point CR1 and extending vertically, perpendicular to the opening surface of the inlet / outlet portion 11 (or the contact surface of the bottom portion 14), is defined as an axis A (first line), and a line connecting the first point CR1 and the second point CR2 and extending at an angle is defined as an axis B (second line). The angle between the axes A and B is defined as an eccentricity angle X. This eccentricity angle X can quantitatively indicate the eccentricity of the container 10. The eccentricity angle X of the container 10 according to this embodiment is large, at 7° or greater, and preferably 10° or greater. The eccentric angle X is not limited to 7° or more, and may be set larger depending on the size of the entrance / exit portion 11.

[0023] When the body 13 is vertically bisected, the upper portion has a substantially trapezoidal shape in a front view. Furthermore, when the body 13 is vertically bisected, the lower portion has a substantially rectangular shape in a front view. The upper portion of the body 13 connected to the major end 121 of the neck 12 is curved so that the distance between the axis A and the body 13 gradually increases downward. The lower portion of the body 13 connected to the major end 121 of the neck 12 extends parallel to the axis A. As illustrated in FIG. 1A, the body 13 connected to the minor end 122 of the neck 12 extends parallel to the axis A. As illustrated in FIGS. 1A and 1B, the top surface of the entrance / exit portion 11 and the bottom surface of the bottom portion 14 are parallel to each other.

[0024] Next, a blow molding apparatus 100 for manufacturing a container will be described with reference to Fig. 2. Fig. 2 is a block diagram of the blow molding apparatus 100.

[0025] 2, the blow molding apparatus 100 includes an injection molding section 110 for manufacturing the preform 20, and a temperature adjustment section 120 for adjusting the temperature of the manufactured preform 20. An injection device 112 for supplying a resin material as a raw material is connected to the injection molding section 110. The blow molding apparatus 100 also includes a blow molding section 130 for blowing the preform 20 to manufacture the container 10, and an ejection section 140 for ejecting the manufactured container 10.

[0026] The injection molding section 110, the temperature adjustment section 120, the blow molding section 130, and the removal section 140 are provided at positions rotated by a predetermined angle (90 degrees in this embodiment) around the conveying means 150. The conveying means 150 is composed of a rotating plate or the like, and is configured so that preforms 20 or containers 10 with their necks 12, 22 supported by neck molds 152 attached to the rotating plate are conveyed to each section as the rotating plate rotates, as exemplified in Figures 4A to 4B and 6A to 6C described below.

[0027] 2 includes an injection cavity mold, an injection core mold, a neck mold, etc. These molds are clamped together to form a preform-shaped space, and a resin material is poured from an injection device 112 into the space, thereby producing a bottomed preform 20.

[0028] Here, a preform 20 according to this embodiment will be described with reference to Figures 3A to 3D. Figure 3A is a front view of the preform 20, Figure 3B is a right side view of the preform 20, Figure 3C is a partially enlarged view of the front view of the preform 20, and Figure 3D is a partially enlarged view of the right side view of the preform 20. The preform 20 is composed of a neck portion 22 having an opening 21, a body portion 23 formed to be continuous with the neck portion 22 and defining the sidewall portion of the preform 20, and a bottom portion 24 formed to be continuous with the body portion 23. A protrusion 25 is provided in the center portion of the bottom portion 24. The protrusion 25 is composed of a gate portion 26 close to the injection gate of the resin used in molding the preform, and a protrusion 27 formed vertically above the gate portion 26 and continuing to the lower end of the preform 20. The protrusion 27 is formed in a flat shape, and is formed to have a larger diameter (wider) than the gate portion 26 in a front view ( FIGS. 3A and 3C ), and is formed to have the same width as the gate portion 26 in a side view ( FIGS. 3B and 3D ). That is, the length of the protrusion 27 in the left-right direction (the width direction in which the protrusion 27 appears wider than the gate portion 26 when the preform 20 is supported by the neck mold 152) is longer than the length of the gate portion 26 in the left-right direction. The length of the protrusion 27 in the front-rear direction (the direction in which the width of the protrusion 27 and the width of the gate portion 26 appear the same when the preform 20 is supported by the neck mold 152) is the same as the length of the gate portion 26 in the front-rear direction.

[0029] Returning to FIG. 2, the blow molding apparatus 100 will be described. The temperature adjustment section 120 is configured to adjust the temperature of the preform 20 manufactured in the injection molding section 110 to a temperature suitable for final blowing. The blow molding section 130 is configured to perform blow molding on the preform 20 whose temperature has been adjusted in the temperature adjustment section 120, to manufacture a resin container 10. The blow molding section 130 includes a blow molding die 200 (see FIG. 4A) and a stretching mechanism (not shown). The stretching mechanism includes a stretching rod 132 (see FIG. 4A) and a blow nozzle (not shown).

[0030] 4A and 4B, the blow molding mold 200 provided in the blow molding section 130 will be described in detail. Fig. 4A is a front view of the mold 200, and Fig. 4B is a right side view of the mold 200. The mold 200 includes a pair of split molds (blow cavity split molds) 210, a bottom mold 220, a pair of neck molds 152, a clamping mechanism 230, and a moving mechanism 240.

[0031] The split mold 210 is configured to be openable and closable in the front-to-rear direction (opening and closing direction D) with the parting surface C as the reference in a side view (FIG. 4B). As illustrated in FIG. 4A, the pair of split molds 210 form a space S that defines the body 13 of the container 10 when closed.

[0032] The bottom mold 220 is composed of a first bottom mold member 221 that defines the bottom 14 of the container 10, and a second bottom mold member (accommodating block) 260 that is disposed below the first bottom mold member 221. The bottom mold 220 also has a clamping mechanism 230 that is accommodated therein (FIGS. 4A and 4B). The first bottom mold member 221 accommodates at least a portion of a clamping section 232 (described below) of the clamping mechanism 230, and the second bottom mold member 260 accommodates at least a portion of an opening / closing mechanism 234 (described below) of the clamping mechanism 230. The second bottom mold member 260 is disposed on the upper surface of a guided section 244 that will be described later. The bottom mold 220 and the guided section 244 are configured to be movable together in the left-right direction (the direction in which the second bottom mold member 260 advances or retreats).

[0033] Here, the clamping mechanism 230 will be described with reference to Figure 5. The clamping mechanism 230 has a clamping part 232 configured to be able to grip the protrusion 27 of the protrusion 25 provided on the bottom 24 of the preform 20. The clamping part 232 is provided independently from the bottom mold 220 (not directly on the bottom mold 220 but separate from it). The clamping part 232 is configured to be openable and closable by an opening / closing mechanism 234 made up of a link mechanism below the bottom mold 220, and clamps the protrusion 27 by changing from an open state to a closed state. A claw part 233 protruding inward from the tip of the clamping part 232 is provided, and is configured so that the claw part 233 bites into the protrusion 27 when the clamping part 232 is closed.

[0034] The first bottom mold member 221 includes a first storage section 236A. The second bottom mold member 260 includes a second storage section 236B. Here, the portion consisting of the first storage section 236A and the second storage section 236B is defined as the storage section 236 in this specification. The first storage section 236A and the second storage section 236B are connected to each other. The storage block 260 and the bottom mold 220 each have an opening for guiding the protruding section 25 of the preform 20 to the clamping section 232. The clamping section 232 and the opening / closing mechanism 234 are covered by the storage section 236. The clamping mechanism 230 is arranged in the storage section 236.

[0035] Returning to Figures 4A and 4B, the mold 200 will be described. The neck mold 152 is attached to the rotating plate as described above, and is configured to transport the preform 20 or the container 10 to each section as the rotating plate rotates while supporting the neck portions 12, 22. The moving mechanism 240 includes, for example, a flat guide groove 242 disposed below the bottom mold 220, and a guided section 244 connected to a moving block (not shown) fixed directly below the storage section 236 (Figure 4A). The guide groove 242 is configured to describe a straight line extending parallel to the top surface of the entrance / exit section 11 of the preform 20.

[0036] The moving mechanism 240 moves the guided portion 244 along the guide groove 242, thereby moving the bottom mold 220 via the moving block parallel to the top surface of the entrance / exit portion 11 of the stationary preform 20 held by the neck mold 152.

[0037] 2, the removal section 140 of the blow molding apparatus 100 will be described. The removal section 140 is configured to release the neck portion 12 of the container 10 manufactured in the blow molding section 130 from the neck mold 152 and remove the container 10.

[0038] 6A to 6C, a method for blow molding the container 10 in the blow molding section 130 of the blow molding apparatus 100 will be described. Fig. 6A is a diagram illustrating a state in which the split mold 210 is open and the preform 20 is accommodated (transported) in the mold 200, Fig. 6B is a diagram illustrating a state in which the protrusion 27 of the preform 20 is gripped by the clamping mechanism 230, and Fig. 6C is a diagram illustrating a state in which the preform 20 is bent. The blow molding process of this embodiment includes a clamping process in which the clamping mechanism 230 of the mold 200 grasps the protrusion 27 of the preform 20 contained in the mold 200 while the split mold 210 of the mold 200 is open; a bending process in which the protrusion 27 of the preform 20 is moved to a position that becomes the eccentric region S2 while the neck portion 22 of the preform 20 is held by the neck mold 152, thereby bending the preform 20; and a blowing process in which the split mold 210 is closed and the preform 20 is stretched by a pressurized medium.

[0039] First, the preform 20, supported by the neck mold 152 and adjusted to a temperature suitable for blow molding by the temperature control unit 120, is transported by the transport means 150 to the blow molding unit 130 and placed in the mold 200 with the split mold 210 open (FIG. 6A). Next, the stretch rod 132, located in a standby position in the blow molding unit 130, is lowered to press the bottom 24 of the preform 20 from the inside, stretching the preform 20 toward the bottom mold 220 (pre-stretching step). The preform 20 is stretched to the bottom mold 220, and the protruding portion 25 of the bottom 24 is placed between the bottom mold 220 and the opening of the storage unit 236 (FIG. 6B). The clamping mechanism 230 grips the protrusion 27 of the accommodated protruding portion 25, connecting the bottom mold 220 of the mold 200 and the bottom 24 of the preform 20 (clamping step). The stretch rod 132 is then raised to its standby position.

[0040] Next, the moving mechanism 240 (FIG. 4A) moves the guided portion 244 leftward (the direction in which the storage block 260 advances) along the guide groove 242 (FIG. 4A). As a result, the bottom mold 220 gripping the protrusion 27 can be moved leftward so as to be parallel to the top surface of the entrance / exit portion 11 of the stationary preform 20 held by the neck mold 152 (FIG. 6C). Therefore, the protrusion 27 moves to the eccentric region S2 outside the projection region S1. As a result, the preform 20 is stretched and bent simultaneously from directly below the neck portion 22 so that the protrusion 27 is eccentric with respect to the axis A (bending process). At this time, the amount of stretching of the body portion of the preform 20 on the left side of the axis A is less than the amount of stretching of the body portion on the right side of the axis A (the body wall of the preform opposite the movement direction of the bottom mold 220 or the storage portion 236 is stretched more than the body wall on the same side as the movement direction). Then, the split mold 210 is closed, and the bent preform 20 is placed in a space S that defines the outer shape of the container 10 and is formed by the neck mold 152, the split mold 210, and the bottom mold 220. In this state, a pressurized medium such as air is introduced into the preform 20, and the preform 20 is blown and stretched to form the container 10 (blowing process). After molding is complete, the split mold 210 is opened to release the container 10, and the container 10 is transported to the removal section 140 by the transport means 150. By using the above method, a container 10 with a large degree of eccentricity can be blow-molded from the preform 20.

[0041] Incidentally, there are off-center containers (off-center bottles) manufactured by blow molding, in which the central axes of the necks are not coaxial. FIG. 7 is a diagram showing an example of a conventional blow molding apparatus 400. As shown in FIG. 7, the stretch rod 133 is slightly inclined with respect to the axis A1 of the preform 20a and the neck mold 252. Here, the area where the bottom 214 of the inner wall surface 202 of the split mold 211 is delimited by two parallel lines extending downward from the lower end of the inner circumferential surface of the inlet / outlet portion 11a of the preform 20a as the base end is defined as region S3. Thus, in the conventional blow molding apparatus 400, the lower end 133a of the stretch rod 133 is located inside region S3. The inner wall surface 202 of the split mold 211, which defines the shape of the eccentric container, is defined by the split mold 211. When air is blown into the interior of the preform 20a through the blow holes, the preform 20a is molded into a shape corresponding to the inner wall surface 202 of the split mold 211 that defines the shape of the eccentric container.

[0042] Examples of conventional eccentric containers include containers in which the gate is located at the center of the bottom and not directly below the neck (entrance / exit portion) (see Patent Document 2 and Patent Document 3), and containers in which the gate is not located at the center of the bottom and is located directly below the neck (see Patent Document 4).

[0043] A container in which the gate is located at the center of the bottom and not directly below the neck (entrance / exit portion 11a) is manufactured by placing a preform 20a in a blow mold, then lowering an inclined stretch rod 133 obliquely while contacting the inner wall surface of the bottom of the preform 20a, and inflating it with blown air. For this reason, the preform 20a used for such a container may have a body thickness distribution that is symmetrical or slightly asymmetrical (i.e., the body of the preform has a slight thickness deviation). Furthermore, the preform 20a is usually designed to have an optimal wall thickness distribution and external shape for each container, taking into consideration the amount of stretching and rigidity of each part corresponding to the container.

[0044] When manufacturing the containers disclosed in Patent Documents 2 and 3, as shown in FIG. 7, the gate portion of the preform 20a is moved to a designed position on the bottom side of the inner wall surface 202 while the preform is biaxially stretched (blowing and expanding). In Patent Document 3, the stretch rod 133 is slightly tilted (rotated) during the preliminary stretching step to forcibly bend the preform 20a and temporarily form a curved preform, which is then lowered obliquely to perform biaxial stretching, thereby preventing misalignment of the gate portion. If necessary, the gate portion of the preform is sandwiched between the top surface of the bottom mold and the tip of the stretch rod and crushed. This is because misalignment of the gate portion relative to the inner wall surface 202 causes misalignment, preventing the preform from being stretched as designed. When misalignment occurs, undesirable phenomena occur, such as gate positions being formed at irregular positions on the bottom, parts of the preform being stretched in directions different from those expected, and the preform coming into contact with the blow cavity surface at unexpected locations. As a result, containers with inferior physical properties such as rigidity and aesthetic appearance may be produced. Therefore, in order to produce such containers with high quality using the stretch blow molding method, it was necessary to position the stretch rod inside the preform during tilt stretching.

[0045] In a rotary plate-type blow molding machine, the stretch rod is housed (placed) in an inclined state so that it can move up and down inside a blow core mold that moves up and down by circulating air. The tip of the blow core mold is small so that it fits airtightly into the neck of the preform. The cylindrical portion above the tip of the blow core mold cannot be made larger in diameter when molding multiple containers simultaneously. Furthermore, the cylindrical portion above the tip of the blow core mold cannot be made larger in diameter, considering the size of the tapered surface that engages with the neck mold.

[0046] Furthermore, the blow core mold must have sufficient rigidity to withstand the clamping force, so the outer wall cannot be made too thin. The stretch rod also needs to be strong enough to withstand the reaction force from the preform during blow molding, so it cannot be made too thin. Due to these structural reasons for the stretching mechanism, the inclination angle of the stretch rod was limited to the small inner diameter space inside the hollow blow core mold. As a result, it has traditionally been difficult to manufacture containers with large eccentric angles using the stretch blow method.

[0047] For example, the eccentricity angle is approximately 5° for a container with an inlet / outlet inner diameter of approximately 36 mm and an outer diameter of approximately 40 mm, and approximately 7° for a container with an inlet / outlet inner diameter of approximately 46 mm and an outer diameter of approximately 50 mm. For this reason, the stretch blow molding methods disclosed in Patent Documents 2 and 3 could only manufacture containers with a small degree of eccentricity (eccentricity angle X).

[0048] Furthermore, the manufacturing method disclosed in Patent Document 4 involves straightening a preform with large wall thickness deviation using a stretching rod and then significantly expanding the side of the thicker preform's barrel with blown air. However, increasing the preform's wall thickness deviation ratio (degree of wall thickness deviation) increases the difference in resin flow rate during injection molding, potentially resulting in poor appearance such as welds (marks of molten resin adhesion) in the barrel. Therefore, in practice, it is difficult to increase the wall thickness deviation ratio. Furthermore, with the manufacturing method disclosed in Patent Document 4, it is also extremely difficult to adjust a preform with large wall thickness deviation to a temperature suitable for blow molding before blow molding. For this reason, when using this method to manufacture containers, especially containers with a high stretch ratio, it is extremely difficult to stretch the preform as designed. Therefore, even with this method, it is not possible to significantly increase the eccentricity (eccentric angle X) of the manufactured container.

[0049] Eccentric containers are also used, for example, in engine oil containers and trigger-type spray containers. Containers with a relatively small eccentricity angle can also be manufactured using the stretch blow molding method by using the inclined stretching mechanisms described in Patent Documents 1 to 3 or the preform with varying wall thickness in the circumferential direction described in Patent Document 4. However, even when these methods are used, the eccentricity (eccentric angle X) of eccentric containers manufactured using these molding methods is limited to approximately 7° to prevent quality defects such as misalignment. In this case, the protruding portion is located within the area (projected area) defined by the intersection of the projection line (extension line) of the outer diameter of the neck and the bottom. In other words, the protruding portion exists within the projected area from the inner diameter of the neck to the bottom. Therefore, containers with a large eccentricity have traditionally been manufactured using the direct blow molding method.

[0050] However, containers manufactured using direct blow molding generally have a poorer aesthetic appearance than those manufactured using stretch blow molding. Furthermore, containers manufactured using direct blow molding are prone to the risk of poor welding (pinholes) at the pinch-off area of ​​the bottom. Containers manufactured using direct blow molding do not have high neck dimensional accuracy, which is necessary for shaping the neck using air blowing. In other words, containers manufactured using direct blow molding are less airtight than those manufactured using stretch blow molding. Furthermore, containers manufactured using direct blow molding require the removal of flash, resulting in a large amount of wasted resin (waste material). Furthermore, containers manufactured using direct blow molding require a post-process called trimming after blow molding. Direct blow molding is difficult to use to manufacture containers with high surface gloss. Therefore, there is a growing demand for the stretch blow molding method to manufacture containers with large eccentricities (eccentric angle X).

[0051] To solve and improve the above-mentioned problems, the present disclosure eliminates the need for a stretching rod, which was previously necessary during inclined stretching, and instead employs a method of holding (clamping) and pulling the preform 20 from the outside of the bottom portion 24 during inclined stretching. This allows the gate portion 26 of the preform 20 to be reliably moved and stopped at the designed position, even when manufacturing a container with a large eccentricity angle. As a result, each part of the body portion of the preform 20 can be stretched as designed. In other words, by using the manufacturing method and manufacturing apparatus according to the present disclosure, it is possible to manufacture a container 10 with a large eccentricity angle X such that the gate portion 26 is deviated from the projection area S1, and with good physical properties (quality).

[0052] Furthermore, the container 10 according to the above embodiment has a protruding portion 25 that protrudes vertically downward on the bottom 14. The container 10 is also largely eccentric to the extent that the protruding portion 25 is located in an eccentric region S2 that is outside the projection region S1. This provides the container 10 with an excellent aesthetic appearance and a large degree of eccentricity.

[0053] Furthermore, in the container 10 according to the above embodiment, the protrusion 27 is wider than the gate 26, so that the clamping mechanism 230 can easily clamp the protruding portion 25, improving the ease of manufacturing the eccentric container.

[0054] Furthermore, according to the manufacturing apparatus, manufacturing method, and blow molding die 200 of the above-described embodiment, a container 10 is manufactured in which the top surface of the inlet / outlet portion 11 of the neck portion 12 is parallel to the bottom surface of the bottom portion 14. Therefore, when the container 10 is placed on a table or the like, the liquid in the container 10 is less likely to spill compared to a container in which the top surface of the inlet / outlet portion 11 is inclined relative to the bottom surface.

[0055] Furthermore, the container 10 according to the above embodiment is provided with a protruding portion 25 that can be clamped by a clamping mechanism 230 of a mold 200 provided in a blow molding section 130 of a blow molding apparatus 100 that uses a stretch blow molding method. This makes it easier to clamp the protruding portion 25 with the clamping mechanism 230, improving the ease of manufacturing an eccentric container.

[0056] Furthermore, according to the manufacturing apparatus, manufacturing method, and blow molding die 200 of the above-described embodiment, after the clamping mechanism 230 grips the protrusion 27 on the bottom 14 of the preform 20, the preform 20 is bent so that the protrusion 27 moves to the eccentricity region S2. The bent preform 20 is stretch-blowed to produce a container 10 with a large degree of eccentricity.

[0057] Furthermore, according to the manufacturing method of the above embodiment, it is possible to manufacture a container 10 with a large degree of eccentricity and excellent aesthetic appearance using a stretch blow molding method, without having to consider the issues with direct blow molding described above.

[0058] The present disclosure is not limited to the above-described embodiments and can be freely modified, improved, etc. The materials, shapes, dimensions, numerical values, forms, numbers, locations, etc. of the components in the above-described embodiments are arbitrary and not limited as long as they can achieve the purpose of the present disclosure.

[0059] In the above embodiment, the container 10 has an eccentric angle X of 7° or more. However, according to the mold 200 and blow molding method of this embodiment, it is possible to manufacture containers with an eccentric angle X of 10° or more by stretch blow molding. Furthermore, the movement of the movement mechanism 240 is not limited to horizontal movement, and may be movement consisting of rotation or linear or multi-step diagonal upward movement.

[0060] In the above embodiment, air is used as an example of a pressurizing medium for blowing the preform 20, but a gas medium other than air may be used, and a liquid medium such as water may also be used for pressurization.

[0061] In the above embodiment, the container 10 is described as having the protruding portion 25, but is not limited to this example. For example, instead of the protruding portion 25, the container may have a remnant formed by cutting out the protruding portion 25. The remnant is located in the eccentric region S2.

[0062] In the above embodiment, the blow molding apparatus 100 is a so-called four-station apparatus in which the temperature adjustment section 120 is provided between the injection molding section 110 and the blow molding section 130, but is not limited to this. The blow molding apparatus 100 may also be, for example, a so-called two-station or three-station apparatus in which the temperature adjustment section 120 is not provided.

[0063] This application is based on a Japanese patent application (Patent Application No. 2018-238111) filed on December 20, 2018, the contents of which are incorporated herein by reference.

Claims

1. a clamping mechanism that is provided independently of the bottom mold of the blow molding mold and that is capable of gripping a protrusion that is provided independently of a gate portion on the bottom of a preform accommodated in the blow molding mold when the split molds of the blow molding mold are open; a moving mechanism that moves the clamping mechanism so that, while the neck of the preform is held, the protrusion is positioned outside an area of ​​the bottom that is vertically projected from an opening plane of the entrance / exit portion of the neck; a stretching mechanism that closes the split mold and stretches the preform using a pressurizing medium; a stretching rod that stretches the bottom of the preform toward the bottom mold before the clamping mechanism grips the protrusion of the preform; and The moving mechanism moves the clamping mechanism together with the bottom mold parallel to the top surface of the entrance / exit section, and the amount of elongation of the preform caused by the moving mechanism moving the clamping mechanism is smaller on the side in the direction of movement of the clamping mechanism than on the opposite side of the direction of movement.

2. a clamping step of gripping a protrusion provided independently of a gate portion on a bottom of a preform accommodated in the blow molding mold with a clamping mechanism provided independently on a bottom mold of the blow molding mold while the split molds of the blow molding mold are open; a bending step of bending the preform by moving the protrusion to the outside of a region of the bottom that is vertically projected from an opening surface of the inlet / outlet portion of the neck while the neck of the preform is held; a blowing step in which the split mold is closed and the preform is stretched by a pressurizing medium; and The method further includes a preliminary stretching step of stretching the bottom of the preform toward the bottom mold by a stretching rod before the clamping step, A method for manufacturing a resin container, wherein in the bending process, the clamping mechanism moves together with the bottom mold parallel to the top surface of the inlet / outlet portion, and the amount of elongation of the preform in the bending process is smaller on the side in the direction of movement of the protrusion portion than on the side opposite the direction of movement.

3. A blow molding mold including a bottom mold, a holding mechanism, a clamping mechanism, and a moving mechanism, the holding mechanism is configured to be able to hold a neck portion of the preform, the clamping mechanism is provided independently on the bottom mold and is configured to be able to grip a protrusion provided independently of a gate portion on the bottom of the preform, the moving mechanism is configured to move the clamping mechanism and the bottom mold so that, with the neck portion of the preform held, the protrusion is positioned outside an area of ​​the bottom portion that is vertically projected from an opening surface of the entrance / exit portion of the neck, the clamping mechanism is configured to grip the protrusion of the preform, the bottom of which has been stretched toward the bottom mold by a stretching rod; the moving mechanism moves the clamping mechanism together with the bottom mold parallel to the top surface of the entrance / exit portion, and the amount of elongation of the preform caused by moving the clamping mechanism and the bottom mold is smaller on the moving direction side of the clamping mechanism than on the opposite side of the moving direction. Mold.

Images