Motor-driven injection blow molding apparatus, container manufactured by the motor-driven injection blow molding apparatus, and motor-driven injection blow molding method

Abstract

To reduce the manufacturing cost of a container.SOLUTION: An electric injection blow molding apparatus is equipped with an extrusion head 9 for extruding a molten resin and an injection mold 10 for filling a cavity C having a shape corresponding to the mouth part 2 of a first container 1 with the molten resin from the extrusion head 9 to perform the injection molding of the mouth part 2. The cavity C has a first cavity side C1 corresponding to the shape of an annular bottom C2 4 of the mouth part 2 facing the extrusion head 9, a second cavity side C3 corresponding to the shape of a cylindrical inside wall 5 rising from the inner edge of the bottom wall 4 of the mouth part 2, and a third cavity side wall corresponding to the shape of a cylindrical outside wall 6 rising from the outer edge of the bottom wall 4 of the mouth part 2. The center pin 15 of the extrusion head 9 has a forming surface C1 serving as the bottom surface of the first cavity 15b.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an electric injection blow molding machine, a container manufactured by the electric injection blow molding machine, and an electric injection blow molding method. [Background technology]

[0002] Patent Document 1 discloses a synthetic resin container having a mouth and a body formed separately from the mouth. The mouth has a circular bottom wall, a cylindrical inner wall rising from the inner edge of the bottom wall, and an outer wall rising from the outer edge of the bottom wall. The inner wall is provided with a slit extending in the direction in which the inner wall rises, and this slit, together with a liquid return port provided in the bottom wall, allows any liquid contents not poured from the mouth to be collected into the body of the container. The mouth configured in this manner is formed by injection molding. Meanwhile, the body is generally formed by direct blow molding. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-290371 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, the mouth portion, which has a relatively complex shape, and the body portion are formed by separate molding methods, so two devices are required to form the container: an injection molding device to form the mouth portion, and a direct blow molding device to form the body portion. Furthermore, the container manufacturing process requires a step of attaching the mouth portion to the body portion, etc. This poses a problem of increased container manufacturing costs.

[0005] The present invention was devised in view of the current situation, and one object of the present invention is to provide an electric injection blow molding machine that can reduce the manufacturing costs of containers, containers manufactured by the electric injection blow molding machine, and an electric injection blow molding method. [Means for solving the problem]

[0006] The present invention relates to an electric injection blow molding machine for molding a container having a mouth and a body integrally formed with the mouth, the molding machine comprising: an extrusion head for extruding molten resin; an injection mold movable relative to the extrusion head and having a cavity shaped to correspond to the mouth and for injection-molding the mouth by filling the cavity with molten resin from the extrusion head; a blow mold disposed between the extrusion head and the injection mold and having a pair of mold halves for clamping a parison formed from a cylindrical extrusion of the molten resin so as to be continuous with the mouth of the injection mold from both sides; and a compressed air supply passage provided in the injection mold for blowing compressed air into the parison to form the body. The cavities include a first cavity corresponding to the shape of the annular bottom wall of the mouth facing the extrusion head, a second cavity corresponding to the shape of a cylindrical inner wall rising from the inner edge of the bottom wall of the mouth, and a third cavity corresponding to the shape of a cylindrical outer wall rising from the outer edge of the bottom wall of the mouth. The extrusion head has a molding surface that serves as the bottom surface of the first cavity. [Effects of the Invention]

[0007] According to the present invention, in a single electric injection blow molding machine, a relatively complex mouth portion having a bottom wall, inner wall, and outer wall is formed by the cavity of the injection mold and the molding surface of the extrusion head, and then a body portion integral with the mouth portion is formed by extruding a parison so that it is continuous with the bottom wall. Therefore, the cost of manufacturing containers can be reduced by using a single electric injection blow molding machine. [Brief explanation of the drawings]

[0008] [Figure 1]FIG. 1(a) is a perspective view of a first container of the first embodiment, and FIG. 1(b) is a cross-sectional view of the opening of the first container taken along line AA in FIG. [Figure 2] 1 is a schematic diagram of an electric injection blow molding device according to a first embodiment. [Figure 3] FIG. 2 is a cross-sectional view of the extrusion head and injection mold of the first embodiment in an abutted state. [Figure 4] FIG. 2 is a perspective view of a core of the injection mold of the first embodiment. [Figure 5] FIG. 2 is a cross-sectional view of the injection mold of the first embodiment in the mold open position. [Figure 6] 2 is a cross-sectional view of a first half mold and a second half mold of the blow mold of the first embodiment. FIG. [Figure 7] 1 shows some of the various steps of the electric injection blow molding method using the electric injection blow molding device of the first embodiment, where (a) shows the extrusion head and injection mold in the initial position, (b) shows the step of butting the injection mold against the extrusion head, and (c) shows the step of injection molding the mouth portion. [Figure 8] 1 shows some of the various steps of the electric injection blow molding method of the first embodiment, where (a) shows the parison extrusion step, and (b) shows the blow mold clamping step and blow-up step. [Figure 9] FIG. 10(a) is a perspective view of a second container of the second embodiment, and FIG. 10(b) is a cross-sectional view of the opening of the second container taken along line BB in FIG. [Figure 10] FIG. 10 is a cross-sectional view of the extrusion head and injection mold of the second embodiment in an abutted state. [Figure 11] FIG. 10 is a cross-sectional view of a first half mold and a second half mold of a blow mold according to a second embodiment. [Figure 12] 10A and 10B show some of the various steps of the electric injection blow molding method using the electric injection blow molding device of the second embodiment, where (a) shows the extrusion head and injection mold in the initial position, (b) shows the step of butting the injection mold against the extrusion head, and (c) shows the step of injection molding the mouth portion. [Figure 13]10A and 10B show some of the various steps of the electric injection blow molding method of the second embodiment, where FIG. 10A shows the parison extrusion step, and FIG. 10B shows the blow mold clamping step and the blow-up step. [Figure 14] FIG. 10 is a schematic view of an electric injection blow molding device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an electric injection blow molding apparatus according to the present invention will now be described with reference to the accompanying drawings.

[0010] First, we will describe a first container 1, which is a spout container formed using an electric injection blow molding machine. The first container 1 is a container made of synthetic resin for holding a liquid, such as liquid detergent or fabric softener. As shown in FIG. 1(a), the first container 1 has a spout 2, which serves as a spout for pouring the liquid, and a body 3 integrally formed with the spout 2. As shown in FIGS. 1(a) and 1(b), the spout 2 has a bottom wall 4 formed in the shape of a continuous circular ring, a cylindrical inner wall 5 rising upward from the inner edge of the bottom wall 4, and a cylindrical outer wall 6 rising from a position near the outer edge of the bottom wall 4. Note that the shape of the bottom wall 4 is not limited to a ring, and may be other ring shapes, such as an ellipse, a teardrop, or a square. As shown in FIG. 1(b), the upper surface 4a of the bottom wall 4 gradually slopes downward from the outer wall 6 to the inner wall 5. As shown in FIG. 1(b), the lower surface 4b of the bottom wall 4 gradually slopes upward from the outer wall 6 to the inner wall 5.

[0011] The inner wall 5 has an inclined portion 5b that slopes downward from its tip 5a. The inner wall 5 has a slit 7 that extends from the portion of the inclined portion 5b closest to the bottom wall 4 to the bottom wall 4. The bottom wall 4 also has an inclined surface 4c at a position opposite the slit 7. This inclined surface 4c gradually slopes downward as it extends radially inward of the inner wall 5. The space surrounded by the bottom wall 4, the inner wall 5, and the outer wall 6 collects liquid that has not been poured from the mouth 2, and this liquid is returned to the main body 3 by passing through the slit 7 along the inclined surface 4c.

[0012] The outer wall 6 is formed so that its height in the rising direction of the inner wall 5 is lower than that of the inner wall 5. A male thread portion 6a is formed on the outer periphery of the outer wall 6, and this male thread portion 6a is threadedly engaged with a female thread portion provided on a cap (not shown).

[0013] As shown in Fig. 1(a), the main body 3 is formed in a cylindrical shape with a bottom and a larger diameter than the outer diameter of the mouth 2. As shown in Fig. 1(b), the open end 3a of the main body 3 is formed integrally with the lower part of the outer periphery of the bottom wall 4 of the mouth 2.

[0014] As shown in FIG. 2, the electric injection blow molding apparatus includes a plasticizing device 8, an extrusion head 9, an injection mold 10, and a blow mold 11.

[0015] The plasticizing device 8 has a hopper 12, which is an inlet for the resin material. The resin material fed into the hopper 12 is plasticized as the screw 13 rotates to become a molten resin, which is then supplied to a resin storage section 14 (described later) of the extrusion head 9.

[0016] The extrusion head 9 is fixed at a predetermined position on the electric injection blow molding machine with the extrusion direction of the molten resin facing upward. The extrusion head 9 has a cylindrical center pin 15, a cylindrical core 16 slidably mounted on the outer periphery of the center pin 15, and a cylindrical die 17 arranged around the core 16.

[0017] As shown in FIG. 3, a molding surface 15b is formed at the top end 15a of the center pin 15 in the vertical direction. This molding surface 15b serves as the bottom surface of a first cavity C1 (described later) for forming the bottom wall 4 of the mouth portion 2 of the first container 1. The molding surface 15b is continuous in an annular shape and gradually slopes downward toward the outer periphery of the center pin 15. In other words, when the injection mold 10 is filled with molten resin and the mouth portion 2 of the first container 1 is injection molded, the molding surface slopes downward from the inner periphery of the annular bottom wall 4 toward the outer periphery. A chamfered portion 15d is formed between the molding surface 15b and the outer periphery 15c of the center pin 15. Furthermore, as shown in FIGS. 2 and 3, a central hole 15e extending along the axial direction of the center pin 15 is formed in the center of the center pin 15.

[0018] As shown in Fig. 3, the upper end 16a of the core 16 is formed in a conical shape. The upper end 16a has a first inclined surface 16b located on the outer periphery of the upper end 16a and inclined at the same inclination angle as the chamfered portion 15d of the center pin 15, a connecting surface 16c continuing from the first inclined surface 16b and parallel to the outer periphery 15c of the center pin 15, and a second inclined surface 16d connected to the first inclined surface 16b via the connecting surface 16c and inclined at the same inclination angle as the first inclined surface 16b. The core 16 is configured to be movable up and down by an actuator (not shown) of the extrusion head drive device 18 provided on the opposite side of the molding surface 15b of the center pin 15.

[0019] As shown in FIG. 3, the upper end 17a of the die 17 is formed in a conical shape. The upper end 17a has an inclined surface portion 17b located on the inner circumferential side of the upper end 17a and inclined at the same inclination angle as the first inclined surface 16b and the second inclined surface 16d of the core 16. The upper end 17a also has an annular abutting surface 17c that faces the injection mold 10 in the vertical direction. A first mold element 19 having a split structure of the injection mold 10 can abut against a circumferential half of the abutting surface 17c. Meanwhile, a second mold element 20 having a split structure of the injection mold 10 can abut against the other circumferential half of the abutting surface 17c.

[0020] Between the core 16 and the die 17, a continuous, annular resin supply passage 21 is formed, which communicates with the resin storage section 14 provided in the extrusion head 9. As shown in FIG. 3, the upper end of the resin supply passage 21 forms a conically tapered first passage 21a formed between the first inclined surface 16b, the connecting surface 16c, and the second inclined surface 16d of the core 16 and the inclined surface section 17b of the die 17. Meanwhile, as shown in FIG. 2, the portion of the resin supply passage 21 other than the first passage 21a forms a linear second passage 21b extending vertically, i.e., in the longitudinal direction of the center pin 15. Note that FIG. 2 only schematically illustrates the shapes of the center pin 15, the core 16, and the die 17, and their actual shapes are as shown in FIG. 3.

[0021] A piston 22 is disposed in the resin storage section 14 and configured to be able to move up and down by an actuator (not shown) of the extrusion head drive device 18. When the piston 22 is moved up by the drive of the extrusion head drive device 18, it extrudes the molten resin in the resin storage section 14 into the resin supply passage 21.

[0022] The injection mold 10 has a cavity C that cooperates with the extrusion head 9 to form the mouth 2 of the first container 1. The cavity C has a first cavity C1 that corresponds to the shape of the annular bottom wall 4 of the mouth 2 that faces the extrusion head 9, a second cavity C2 that corresponds to the shape of a cylindrical inner wall 5 that rises from the inner edge of the bottom wall 4 of the mouth 2, and a third cavity C3 that corresponds to the shape of a cylindrical outer wall 6 that rises from a position near the outer edge of the bottom wall 4 of the mouth 2.

[0023] The injection mold 10 is disposed above and opposite the extrusion head 9 and is movable relative to the extrusion head 9. More specifically, the injection mold 10 can be lowered from an initial position (as shown in FIG. 2 ) to an abutting position (as shown in FIG. 3 ) where it abuts against the abutting surface 17c of the extrusion head 9 by an actuator (not shown) of an injection mold drive device 23 provided on the injection mold 10, and can also be raised from this abutting position to the initial position. The injection mold 10 further includes a core 24 and a first half-shaped mold element 19 and a second half-shaped mold element 20 that are configured to clamp and open the core 24 horizontally by actuators (not shown) provided on a first opening / closing device 25 and a second opening / closing device 26, respectively. The first half-shaped mold element 19 and the second half-shaped mold element 20 move between a clamping position (as shown in FIG. 3 ) and an opening position (as shown in FIG. 5 ). The split mold, which is configured to sandwich the core and allow for horizontal mold closing and mold opening operations, may be divided into three or more parts.

[0024] The core 24 has a disk-shaped base wall portion 24a, a columnar shaft portion 24b protruding from the center of the base wall portion 24a toward the extrusion head 9, and a cylindrical peripheral wall portion 24c protruding from the base wall portion 24a toward the extrusion head 9 around the shaft portion 24b. A shaft-chamfered portion 24e is formed on the outer peripheral edge of a tip portion 24d of the shaft portion 24b. As shown in FIG. 3, the length of the shaft portion 24b in the vertical direction is longer than the length of the peripheral wall portion 24c in the vertical direction. The tip portion 24d of the shaft portion 24b is fitted into a central hole 15e provided in a center pin 15 during a butting process of the injection mold 10 described below and an injection molding process described below. A circular inclined surface 24g is formed on a tip portion 24f of the peripheral wall portion 24c, gradually inclining upward as it extends radially outward from the shaft portion 24b. The outer peripheral surface 24h of the peripheral wall portion 24c is formed in a stepped shape so that the diameter on the tip portion 24f side is smaller than that on the base wall portion 24a side. As shown in FIG. 4, a portion of the outer peripheral surface 24i of the stem portion 24b is connected to a portion of the inner peripheral surface 24j of the peripheral wall portion 24c by a connecting portion 27 extending in the axial direction of the stem portion 24b. This connecting portion 27 corresponds to the slit 7 provided in the inner wall 5 of the mouth portion 2 of the first container 1. The space surrounded by the stem portion 24b, the peripheral wall portion 24c, and the connecting portion 27 corresponds to the second cavity C2 that forms the inner wall 5 of the mouth portion 2, and the second cavity C2 is continuous in a C-shape when viewed from the upright direction of the inner wall 5 of the mouth portion 2 of the first container 1, as shown in FIG. 4.

[0025] 3, the shaft portion 24b and the base wall portion 24a are formed with a compressed air supply passage 28 for supplying compressed air into the parison P in a blow-up process described later. The compressed air supply passage 28 is connected to a compressed air supply source (not shown).

[0026] The first die element 19 and the second die element 20 are formed in a semicircular arc shape so as to cooperate with each other to form a cylindrical die. The inner peripheral surface 19a of the first die element 19 and the inner peripheral surface 20a of the second die element 20 have shapes corresponding to the outer peripheral portions of the outer wall 6 and the bottom wall 4 of the first container 1. The space between the inner peripheral surfaces 19a, 20a and the peripheral wall portion 24c of the core 24 corresponds to the third cavity C3 that forms the outer wall 6 of the mouth portion 2.

[0027] In addition, the space surrounded by the inclined surface 24g of the peripheral wall portion 24c, the inner peripheral surface 19a of the first mold element 19, the inner peripheral surface 20a of the second mold element 20, and the molding surface 15b of the center pin 15 corresponds to the first cavity C1 that forms the bottom wall 4 of the mouth portion 2.

[0028] As shown in Figure 3, the lower end surfaces 19b, 20b of the first mold element 19 and the second mold element 20 of the injection mold 10 are abutted against the abutting surface 17c of the die 17 of the extrusion head 9, and molten resin is extruded from the resin supply passage 21 into the cavity C of the injection mold 10 to fill it, thereby injection molding the mouth portion 2. Here, the molten resin flowing through the resin supply passage 21 is at a relatively high temperature, so even after the molten resin is supplied to the cavity C, it remains at a relatively high temperature for a while. Therefore, the formation of the main body portion 3 is not performed until the relatively high-temperature mouth portion 2 cools and solidifies or reaches a state close to solidification.

[0029] The blow mold 11 is a mold used to form the main body 3 of the first container 1. The blow mold 11 has a first mold half 29 and a second mold half 30 that clamp a parison P (see FIG. 8(a)) from both sides, which is formed by extruding molten resin into a cylindrical shape so that it continues into the mouth 2 of the injection mold 10. The first mold half 29 and the second mold half 30 are arranged symmetrically across the axis L of the extrusion head 9 and the injection mold 10, as shown in FIG. 2. A platen 31 is provided behind each of the first mold half 29 and the second mold half 30, and this platen 31 is clamped and opened by an actuator (not shown) provided in a blow mold drive device 32. When clamping, the first mold half 29 and the second mold half 30 are positioned between the extrusion head 9 and the injection mold 10.

[0030] The first and second mold halves 29 and 30 have a similar shape, for example, a rectangular parallelepiped block. As shown in Fig. 6, the first and second mold halves 29 and 30 have a first surface 29a and a second surface 30a that correspond to the outer shapes of the corresponding halves of the main body 3 of the first container 1. A first relief groove 29b and a second relief groove 30b are provided adjacent to the upper ends of the first and second surfaces 29a and 30a to avoid interference with the first and second mold elements 19 and 20 of the injection mold 10 during mold clamping. The first and second relief grooves 29b and 30b are each continuous in a semicircular arc shape. In addition, a first blade portion 29c and a second blade portion 30c are formed on the inner periphery of the first half mold 29 and the second half mold 30 adjacent to the lower ends of the first surface 29a and the second surface 30a, respectively, to cut out the lower portion of the cylindrical parison P.

[0031] Next, an electric injection blow molding method using the electric injection blow molding apparatus of the first embodiment will be described with reference to FIGS. 7(a) to 7(c), 8(a) and 8(b).

[0032] First, in the initial position of the injection mold 10 shown in FIG. 7(a), the injection mold 10 is located above and spaced apart from the extrusion head 9 which is fixed at a predetermined position.

[0033] 7(b), the injection mold 10 is lowered from its initial position shown in FIG. 7(a) to bring the bottom end surfaces 19b and 20b of the first mold element 19 and second mold element 20 of the injection mold 10 into contact with the contact surface 17c of the die 17 of the extrusion head 9. When the bottom end surfaces 19b and 20b are in contact with the contact surface 17c, the tip end 24d of the shaft portion 24b of the core 24 is fitted into the central hole 15e of the center pin 15.

[0034] Then, in the injection molding step shown in FIG. 7(c), the mouth portion 2 of the first container 1 is injection molded by extruding molten resin from the resin supply passage 21 into the cavity C of the injection mold 10 to fill it.

[0035] After the mouth portion 2 has solidified, in the parison extrusion process shown in Figure 8(a), which is the process subsequent to Figure 7(c), the injection mold 10 equipped with the mouth portion 2 is raised and moved away from the extrusion head 9, while the molten resin is extruded cylindrically so as to be continuous with the outer periphery of the bottom wall 4 of the mouth portion 2 inside the injection mold 10, to form a cylindrical parison P of a predetermined thickness.

[0036] After the parison P is formed, in the clamping step of the blow mold 11 shown in FIG. 8(b), the first mold half 29 and the second mold half 30 of the blow mold 11 are clamped.

[0037] Then, in the blow-up process also shown in Figure 8(b), compressed air is blown into the parison P through the compressed air supply passage 28 provided in the core 24 to inflate the parison P, and the parison P is made to follow the first surface 29a and the second surface 30a of the first half mold 29 and the second half mold 30, thereby forming the main body portion 3 of the first container 1.

[0038] After the main body portion 3 is formed, the first half mold 29 and the second half mold 30 of the blow mold 11 are opened, and then the first mold element 19 and the second mold element 20 of the injection mold 10 are opened, thereby removing the first container 1.

[0039] As described above, in the first embodiment, the cavity C has a first cavity C1 corresponding to the shape of the annular bottom wall 4 of the mouth portion 2 facing the extrusion head 9, a second cavity C2 corresponding to the shape of the cylindrical inner wall 5 rising from the inner edge of the bottom wall 4 of the mouth portion 2, and a third cavity C3 corresponding to the shape of the cylindrical outer wall 6 rising from a position near the outer edge of the bottom wall 4 of the mouth portion 2. In addition, the center pin 15 of the extrusion head 9 has a molding surface 15b that forms the bottom surface of the first cavity C1. Therefore, the mouth portion 2 having a relatively complex shape, including the bottom wall 4, inner wall 5, and outer wall 6, is molded by the electric injection blow molding device. During this molding, the lower surface 4b of the bottom wall 4, which serves as a base for joining the main body portion 3, is efficiently formed by the molding surface 15b of the center pin 15. Then, by using the same electric injection blow molding device, the cylindrical parison P is continuously extruded onto the lower portion of the outer periphery of the bottom wall 4, thereby molding the first container 1 in which the mouth portion 2 and the main body portion 3 are integrated. Therefore, because the mouth portion 2 and the main body portion 3 are molded by a single electric injection blow molding device, the manufacturing costs of the first container 1 can be reduced compared to when a container having a similar shape to the first container 1 is manufactured using an injection molding device that forms the mouth portion and a direct blow molding device that forms the main body portion.

[0040] Furthermore, when manufacturing a container having a shape similar to the first container 1 of this embodiment, the mouth and main body of the container may be molded from different types of synthetic resin materials, which may reduce the recyclability of the container and increase the manufacturing costs of the container.

[0041] However, in this embodiment, the mouth portion 2 is molded from molten resin, and then the body portion 3 is molded from a parison P made of the same molten resin material as the mouth portion 2 so as to be continuous with the bottom wall 4 of the mouth portion 2. Therefore, the entire first container 1 is molded from a single synthetic resin material. This improves the recyclability of the first container 1 and reduces the manufacturing cost of the first container 1.

[0042] Furthermore, in this embodiment, the molding surface 15b of the center pin 15 of the extrusion head 9 is inclined downward from the inner periphery toward the outer periphery of the bottom wall 4 of the mouth portion 2. Therefore, the inclined lower surface 4b of the bottom wall 4 is formed in a manner that is transferred to the inclined molding surface 15b. Therefore, when the first container 1 containing liquid is inverted so that the mouth portion 2 faces downward, the liquid can be quickly discharged along the inclined lower surface 4b.

[0043] Furthermore, the second cavity C2 is continuous in a C-shape when viewed from the standing direction of the inner wall 5 of the mouth portion 2. The second cavity C2 forms the slit 7 in the inner wall 5 by a connecting portion 27 between the shaft portion 24b and the peripheral wall portion 24c of the core 24. By providing the connecting portion 27 in the core 24 in this way, the slit 7 can be formed by molding without machining, thereby reducing the manufacturing time and cost of the first container 1.

[0044] FIG. 9(a) is a perspective view of a second container 33 of the second embodiment, and FIG. 9(b) is a cross-sectional view of the opening 34 of the second container 33 taken along line BB in FIG. 9(a).

[0045] The second container 33 is a spout container made of synthetic resin. The second container 33 has a mouth 34, which serves as a spout for pouring liquid, and a main body 35 formed integrally with the mouth 34. As shown in FIGS. 9(a) and 9(b), the mouth 34 has a bottom wall 36 formed in the shape of a continuous annular plate, and a cylindrical tube wall 37 standing upward from the inner edge of the bottom wall 36. As shown in FIG. 9(b), the bottom wall 36 has an upper surface 36a exposed to the outside and a lower surface 36b exposed to the inside of the main body 35 and parallel to the upper surface 36a. An annular protrusion 37a is formed on the outer peripheral surface of the tube wall 37 at a position close to the bottom wall 36, protruding radially outward from the outer peripheral surface of the tube wall 37. Furthermore, a male thread portion 37b is formed on the outer peripheral surface of the cylindrical wall 37 at a position above the protrusion 37a, and this male thread portion 37b is threadedly engaged with a female thread portion provided on a cap (not shown).

[0046] As shown in Fig. 9(a), the main body 35 is formed in a generally rectangular box shape. As shown in Fig. 9(b), the open end 35a of the main body 35 is formed integrally with the lower portion of the outer periphery of the bottom wall 36 of the mouth 34.

[0047] Furthermore, unlike the inclined molding surface 15b of the center pin 15 of the first embodiment, the center pin 15 of the extrusion head 9 of this embodiment has a circular molding surface 15f that extends in the vertical direction, i.e., in a direction perpendicular to the longitudinal direction of the center pin 15.

[0048] Furthermore, in this embodiment, an injection mold 38 is newly provided for forming the mouth portion 34 of the second container 33. The injection mold 38 has a cavity C that cooperates with the extrusion head 9 to form the mouth portion 34 of the second container 33. The cavity C has a fourth cavity C4 that corresponds to the shape of the annular bottom wall 36 of the mouth portion 34 that faces the extrusion head 9, and a fifth cavity C5 that corresponds to the shape of the cylindrical tube wall 37 that stands up from the inner edge of the bottom wall 36 of the mouth portion 34.

[0049] The injection mold 38 has a core 39 and a third mold element 40 and a fourth mold element 41 which are split in half and configured to clamp the core 39 horizontally and enable mold opening and closing operations by actuators (not shown) provided in the first opening / closing device 25 and the second opening / closing device 26, respectively.

[0050] The core 39 is formed in a cylindrical shape, and has therein a compressed air supply passage 28 for supplying compressed air into the parison P (see FIG. 13(b)).

[0051] The third die element 40 and the fourth die element 41 are formed in a semicircular arc shape so as to cooperate with each other to form a cylindrical die. The inner peripheral surface 40a of the third die element 40 and the inner peripheral surface 41a of the fourth die element 41 have shapes corresponding to the outer shape of the cylindrical wall 37 of the second container 33 and the outer shapes of the upper and lateral sides of the bottom wall 36. As shown in FIG. 10 , the space surrounded by a part of the core 39, parts of the third die element 40 and the fourth die element 41, and the molding surface 15f of the center pin 15 corresponds to the fourth cavity C4 that forms the bottom wall 36 of the mouth portion 34. The space between a part of the core 39 and parts of the third die element 40 and the fourth die element 41 corresponds to the fifth cavity C5 that forms the cylindrical wall 37 of the mouth portion 34.

[0052] In this embodiment, the blow mold 42 is used to form the main body 35 of the second container 33. As shown in Fig. 11, the blow mold 42 has a third mold half 43 and a fourth mold half 44 that can be clamped and opened, and the third mold half 43 and the fourth mold half 44 have a third surface 43a and a fourth surface 44a that correspond to the outer shapes of the corresponding halves of the main body 35 of the second container 33.

[0053] Next, an electric injection blow molding method using the electric injection blow molding apparatus of the second embodiment will be described with reference to FIGS. 12(a) to 12(c), 13(a) and 13(b).

[0054] First, in the initial position of the injection mold 38 shown in FIG. 12(a), the injection mold 38 is located above and spaced apart from the extrusion head 9 which is fixed at a predetermined position.

[0055] 12(b), the injection mold 38 is lowered from its initial position shown in FIG. 12(a) to bring the bottom end surfaces 40b and 41b of the third mold element 40 and fourth mold element 41 of the injection mold 38 into contact with the contact surface 17c of the die 17 of the extrusion head 9. When the bottom end surfaces 40b and 41b are in contact with the contact surface 17c, the tip end portion 39a of the core 39 is fitted into the central hole 15e of the center pin 15.

[0056] Then, in the injection molding step shown in FIG. 12(c), the opening 34 of the second container 33 is injection molded by extruding molten resin from the resin supply passage 21 into the cavity C of the injection mold 38 and filling it.

[0057] Next, in the parison extrusion process shown in Figure 13(a), which is the process subsequent to Figure 12(c), an injection mold 38 equipped with a mouth portion 34 is raised and moved away from the extrusion head 9, while molten resin is extruded cylindrically so as to be continuous with the outer periphery of the bottom wall 36 of the mouth portion 34 inside the injection mold 38, thereby forming a cylindrical parison P of a predetermined thickness.

[0058] After the parison P is formed, in a clamping step of the blow mold 42 shown in FIG. 13(b), the third mold half 43 and the fourth mold half 44 of the blow mold 42 are clamped.

[0059] Then, in the blow-up process also shown in Figure 13(b), compressed air is blown into the parison P through the compressed air supply passage 28 provided in the core 39 to inflate the parison P, and the parison P is made to follow the third surface 43a and the fourth surface 44a of the third half mold 43 and the fourth half mold 44, thereby forming the main body portion 35 of the second container 33.

[0060] After the main body portion 35 is formed, the third half mold 43 and the fourth half mold 44 of the blow mold 42 are opened, and then the third mold element 40 and the fourth mold element 41 of the injection mold 38 are opened, thereby removing the second container 33.

[0061] As described above, in the second embodiment, the mouth portion 34 and the main body portion 35 are molded by a single electric injection blow molding device, so the manufacturing cost of the second container 33 can be reduced compared to manufacturing a container of a similar shape to the second container 33 using an injection molding device that forms the mouth portion and a direct blow molding device that forms the main body portion.

[0062] Also in this embodiment, the mouth portion 34 is molded from molten resin, and then the main body portion 35 is molded from a parison P made of the same molten resin material as the mouth portion 34 so as to be continuous with the bottom wall 36 of the mouth portion 34. This means that the entire second container 33 is molded from a single synthetic resin material. This improves the recyclability of the second container 33 and reduces the manufacturing cost of the second container 33.

[0063] FIG. 14 schematically illustrates an electric injection blow molding apparatus according to a third embodiment. Unlike the first embodiment, the third embodiment has a recess 15g formed in the molding surface 15f of the center pin 15, rather than a central hole 15e, into which the tip 24d of the shank 24b of the core 24 is fitted during the butting and injection molding processes. A cooling passage 45 is formed below the recess 15g in the center pin 15 to cool the upper end 15a, including the molding surface 15b (see FIG. 3), of the center pin 15. Cooling air is supplied into this cooling passage 45 from a cooling air supply source (not shown). Cooling water may be supplied into the cooling passage 45 from a cooling water supply source (not shown) instead of cooling air. As shown by the portion inside the double dashed line in Fig. 14, the cooling path 45 extends from the lower end side (extrusion head drive device 18 side) of the center pin 15 (not shown) to the vicinity of the recess 15g, turns back in a U-shape, and returns to the lower end side of the center pin 15. Cooling air is supplied to the cooling path 45 after the molten resin has been filled into the cavity C in the injection molding process (Fig. 7(c)). Note that the supply of cooling air to the cooling path 45 may also be applied to the injection molding process of the second embodiment (Fig. 12(c)).

[0064] As described above, in the third embodiment, cooling air is supplied through the cooling path 45 to the vicinity of the recess 15g of the center pin 15 during the injection molding process. This cools the molding surface 15b of the center pin 15, and further cools the molten resin in the cavity C, causing it to solidify quickly, thereby shortening the injection molding process. Furthermore, cooling the molding surface 15b of the center pin 15 sufficiently solidifies the lower surface of the bottom wall 36 of the mouth portion 34, improving the releasability of the bottom wall 36 of the mouth portion 34 from the molding surface 15b of the center pin 15. [Explanation of symbols]

[0065] 1...1st container 2...Mouth 3. Main body 4. Bottom wall 5...Inner wall 6. Exterior wall 7. Slit 9. Extrusion head 10. Injection mold 11. Blow mold 15···Center pin 15b...molding surface C···cavity C1: First cavity C2: Second cavity C3: Third cavity 19. First mold element 20...Second mold element 24...Nakako 28 Compressed air supply line P...Parison

Claims

1. An electric injection blow molding apparatus for molding a container having a mouth portion and a body portion formed integrally with the mouth portion, an extrusion head that extrudes molten resin; an injection mold that is disposed movably relative to the extrusion head, includes a cavity having a shape corresponding to the mouth portion, and injects the molten resin from the extrusion head into the cavity to injection-mold the mouth portion; a blow mold having a pair of half halves that is disposed between the extrusion head and the injection mold and clamps a parison formed by extruding the molten resin into a cylindrical shape so as to be continuous with the opening of the injection mold from both sides; a compressed air supply path provided in the injection mold for blowing compressed air into the parison to form the main body portion; Equipped with The cavity is a first cavity corresponding to the shape of an annular bottom wall of the mouth portion facing the extrusion head; a second cavity corresponding to the shape of a cylindrical inner wall rising from the inner edge of the bottom wall of the mouth portion; a third cavity corresponding to the shape of a cylindrical outer wall rising from the outer edge of the bottom wall of the mouth portion, The extrusion head has a molding surface that becomes the bottom surface of the first cavity. An electric injection blow molding device characterized by:

2. 2. The electric injection blow molding device according to claim 1, wherein the molding surface of the extrusion head is inclined downward from the inner periphery of the bottom wall toward the outer periphery.

3. 2. The electric injection blow molding device according to claim 1, wherein the second cavity is continuous and C-shaped when viewed from the standing direction of the inner wall of the mouth portion.

4. A container manufactured by the electric injection blow molding device according to any one of claims 1 to 3.

5. 1. An electric injection blow molding method for molding a container having a mouth portion and a body portion formed integrally with the mouth portion, comprising: an injection mold having a cavity for forming the mouth portion and an extrusion head are butted together, and molten resin is injected from the extrusion head into the cavity to injection mold the mouth portion; While separating the injection mold from the extrusion head, the molten resin is extruded in a cylindrical shape so as to be continuous with the opening portion of the injection mold, thereby forming a parison; A pair of half halves of a blow mold are clamped from both sides of the parison, blowing compressed air into the parison to form the body portion; The cavity is a first cavity corresponding to the shape of an annular bottom wall of the mouth portion facing the extrusion head; a second cavity corresponding to the shape of a cylindrical inner wall rising from the inner edge of the bottom wall of the mouth portion; a third cavity corresponding to the shape of a cylindrical outer wall rising from the outer edge of the bottom wall of the mouth portion, The extrusion head has a molding surface that becomes the bottom surface of the first cavity. An electric injection blow molding method characterized by:

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