Blow molding apparatus and blow molding method

Abstract

To provide a blow molding apparatus and a blow molding method for performing a liquid blow molding process and a gas blow molding process by using the same nozzle.SOLUTION: A blow-molding device 1 includes a mold 2, a nozzle 3 having a liquid supply passage 3b, and a seal body 4 that reciprocates between a closed position and an open position, and supplies a pressurized liquid into a predetermined preform 12 through the liquid supply passage 3b when the seal body 4 is at the open position. A pressurized liquid supply source 6 for blow-molding the preform 12 into a predetermined container, a gas supply passage 7, and a pressurized gas supply source 8 for blow-molding the preform 12 into another container by supplying pressurized gas into the other preform 12 through the gas supply passage 7 when the seal body 4 is at the closed position are provided.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a blow molding apparatus and a blow molding method. [Background technology]

[0002] There are known blow molding machines that blow mold preforms into containers and that use both liquid and gas as the pressurized fluid supplied to the interior of the preforms. For example, Patent Document 1 discloses a blow molding machine that has an interchangeable liquid supply nozzle and a gas supply nozzle. Patent Document 2 also discloses a blow molding machine that first supplies pressurized gas to the preform to start blow molding, and then switches the pressurized fluid to pressurized liquid to mold the preform into a container. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5808733 [Patent Document 2] U.S. Patent Application Publication No. 2013 / 113143 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a need for a blow molding apparatus that uses the same nozzle to perform a liquid blow molding process in which a given preform is blow molded into a given container using pressurized liquid, and a gas blow molding process in which another preform is blow molded into another container using pressurized gas.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a blow molding apparatus and a blow molding method that use the same nozzle for both the liquid blow molding process and the gas blow molding process. [Means for solving the problem]

[0006] One aspect of the present invention is as follows.

[0007] [1] a mold having a cavity; a nozzle having a cylindrical nozzle tip, a liquid supply passage extending to a tip of a central opening of the nozzle tip, an annular sealing surface facing the liquid supply passage, and a supply port forming a part of the liquid supply passage and extending from an inner peripheral edge of the sealing surface to the tip of the central opening of the nozzle tip; a seal body that reciprocates in the axial direction between a closed position where it comes into close contact with the seal surface to close the liquid supply passage and an open position where it moves away from the seal surface to open the liquid supply passage; a pressurized liquid supply source that supplies pressurized liquid through the liquid supply path into the interior of a predetermined preform that is placed in the molding die and in close contact with the nozzle tip when the seal body is in the open position, thereby blow-molding the preform into a predetermined container that conforms to the shape of the cavity; a gas supply path that opens to the supply port, passes through the inside of the nozzle, and communicates with the inside of another preform that is in close contact with the nozzle tip; and a pressurized gas supply source that supplies pressurized gas through the gas supply path to the inside of the other preform that is placed in the mold and in close contact with the nozzle tip when the seal body is in the closed position, thereby blow-molding the preform into another container that conforms to the shape of the cavity.

[0008] [2] a rod extending in an elongated shape in the axial direction radially inside the cylindrical seal body extending in the axial direction and reciprocating in the axial direction; the seal body has a seal tip tube that extends from a portion located on the inner circumferential edge of the seal surface toward a tip of the supply port when the seal body is in the closed position, The blow molding apparatus described in [1], wherein the gas supply path has a radial supply path extending radially toward the supply port, and a tip flow path that is configured by a recess provided in one or both of the nozzle and the seal tip tube, and that connects the radial supply path to the interior of the other preform that is placed in the molding die and in close contact with the nozzle tip.

[0009] [3] a discharge path that opens to the supply port, passes through the inside of the nozzle, and communicates with the inside of the predetermined container that is disposed in the mold and in close contact with the tip of the nozzle; a suction source that draws the liquid through the discharge passage when the seal is in the closed position; the discharge path has a radial discharge path extending in the radial direction toward the supply port, The blow molding apparatus described in [2], wherein the tip flow path connects the radial discharge path to the interior of the specified container placed in the mold and in close contact with the nozzle tip, and also serves as part of the discharge path.

[0010] [4] the radial supply passage and the radial discharge passage each open to the supply port, The tip flow path has a tip recess provided on the inner surface of the seal tip tube and extending to the tip of the seal tip tube, a radial supply port that penetrates the seal tip tube in the radial direction to connect the radial supply path to the tip recess when the seal body is in the closed position, and a radial discharge port that penetrates the seal tip tube in the radial direction to connect the radial discharge path to the tip recess when the seal body is in the closed position. [3] The blow molding apparatus described in

[0011] [5] A blow molding method using the blow molding apparatus according to any one of [1] to [4], a liquid blow molding process in which the pressurized liquid is supplied from the pressurized liquid supply source through the liquid supply path into the interior of the predetermined preform that is placed in the mold and in close contact with the nozzle tip when the seal body is in the open position, thereby blow-molding the preform into the predetermined container that conforms to the shape of the cavity; and a gas blow molding step of blow-molding the preform into the other container that conforms to the shape of the cavity by supplying the pressurized gas from the pressurized gas supply source through the gas supply path into the inside of the other preform that is placed in the mold and in close contact with the nozzle tip when the seal body is in the closed position. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a blow molding apparatus and a blow molding method in which the liquid blow molding step and the gas blow molding step are performed using the same nozzle. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram showing a blow molding device according to an embodiment of the present invention. [Figure 2] 2 is a vertical cross-sectional view showing in more detail a portion of the blow molding apparatus shown in FIG. 1. FIG. [Figure 3] FIG. 3 is a bottom view of the blow molding device shown in FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0015] As shown in Figures 1 to 3, in one embodiment of the present invention, a blow molding apparatus 1 includes a mold 2, a nozzle 3, a seal member 4, a rod 5, a pressurized liquid supply source 6, a gas supply channel 7, a pressurized gas supply source 8, a discharge channel 9, a suction source 10, and an assist gas supply source 11. These components are integrally controlled by a computer-based control device (not shown) for blow molding. The blow molding apparatus 1 uses biaxial stretch blow molding to mold a preform 12, which has a mouth portion 12a and a bottomed, tubular stretched portion 12b, in this order, into a container (not shown), which has a mouth portion 12a, a body portion, and a bottom portion, in this order. More specifically, the blow molding apparatus 1 uses the same nozzle 3 to perform a liquid blow molding process in which a given preform 12 is molded into a given container, and a gas blow molding process in which another preform 12 is molded into another container.

[0016] The mold 2 has a cavity 2a shaped to fit the outer shapes of the body and bottom of the container. A resin preform 12 adjusted to a temperature at which it can be stretched is placed in the mold 2 so that the stretched portion 12b is inserted into the cavity 2a, leaving only the mouth portion 12a. After the container is molded, the mold 2 performs a mold opening operation to open the cavity 2a, and the container is removed from the cavity 2a.

[0017] The nozzle 3 has a nozzle tip 3a that is cylindrical and circular when viewed from the bottom, centered on the central axis O, a liquid supply path 3b that extends to the tip of the central opening of the nozzle tip 3a, an annular sealing surface 3c that faces the liquid supply path 3b, and a supply port 3d that forms part of the liquid supply path 3b and extends from the inner peripheral edge of the sealing surface 3c to the tip of the central opening of the nozzle tip 3a.

[0018] In this embodiment, the direction along the central axis O is referred to as the axial direction, the direction perpendicular to the central axis O is referred to as the radial direction, and the direction going around the central axis O is referred to as the circumferential direction. In this embodiment, the axial direction is the vertical direction, and the supply port 3d of the nozzle 3 supplies pressurized liquid downward during blow molding.

[0019] The seal body 4 has a cylindrical shape extending in the axial direction around the central axis O, and reciprocates in the axial direction between a closed position (position shown in FIG. 1) where it is in close contact with the seal surface 3c to block the liquid supply path 3b, and an open position where it is removed from the seal surface 3c to open the liquid supply path 3b. The seal body 4 also has a seal tip tube 4a that extends from a portion located on the inner periphery of the seal surface 3c toward the tip of the supply port 3d when the seal body 4 is in the closed position. It is preferable that the seal tip tube 4a be positioned so that it fits within the supply port 3d when the seal body 4 is in the closed position.

[0020] The rod 5 extends elongated in the axial direction around the central axis O inside the radial direction of the seal body 4 and reciprocates in the axial direction. In this embodiment, the rod 5 is used as a stretch rod 5 that presses the bottom of the preform 12 from inside the preform 12 to stretch it in the axial direction for biaxial stretch blow molding. The rod 5 also has a liquid flow path (not shown) inside that discharges liquid from the lower end of the rod 5 to form a headspace from inside the specified container after molding.

[0021] Pressurized liquid supply source 6 supplies pressurized liquid through liquid supply path 3b into the interior of the predetermined preform 12, which is arranged in mold 2 and has the inner peripheral surface of mouth 12a in close contact with nozzle tip 3a, when seal body 4 is in the open position, thereby blow-molding the preform 12 into the predetermined container that conforms to the shape of cavity 2a. Pressurized liquid supply source 6 is configured by a plunger pump that pressurizes liquid supplied appropriately from tank 13 and supplies it to liquid supply path 3b, but is not limited to this. In this embodiment, the pressurized liquid is the content of a product that is housed in a container and distributed.

[0022] The gas supply path 7 opens to the supply port 3d, passes through the nozzle 3, and communicates with the interior of the other preform 12 that is in close contact with the nozzle tip 3a. The gas supply path 7 has a radial supply path 7a extending radially to the supply port 3d and a tip flow path 14 that connects the radial supply path 7a to the interior of the other preform 12 that is arranged in the mold 2 for gas blow molding and is in close contact with the nozzle tip 3a. The tip flow path 14 has a tip recess 14a that is provided on the inner circumferential surface of the seal tip tube 4a and extends to the tip of the seal tip tube 4a, and a radial supply port 14b that radially penetrates the seal tip tube 4a and connects the radial supply path 7a to the tip recess 14a when the seal body 4 is in the closed position. A plurality of tip recesses 14a are provided at intervals in the circumferential direction. In this case, an annular recess that circumferentially connects the plurality of tip recesses 14a may be provided on the inner circumferential surface of the seal tip tube 4a. The gas supply path 7 passes pressurized gas through the radial supply path 7a, radial supply port 14b, and tip recess 14a in this order. The tip flow path 14 may be provided between the outer peripheral surface of the seal tip tube 4a and the nozzle 3. The gas supply path 7 has a gas valve 7b that opens and closes the flow path between the pressurized gas supply source 8 and the downstream end of the gas supply path 7 (the tip of the tip flow path 14). The gas valve 7b is built into the nozzle 3 so as to open and close the radial supply path 7a, but is not limited to this.

[0023] The pressurized gas supply source 8 is disposed in the mold 2 for gas blow molding. When the seal body 4 is in the closed position, pressurized gas is supplied through the gas supply path 7 to the inside of the other preform 12, the inner circumferential surface of which is in intimate contact with the nozzle tip 3a. This blow-moldes the preform 12 into the other container conforming to the shape of the cavity 2a. In this embodiment, the pressurized gas supply source 8 is switched between a first supply source 8a that supplies pressurized gas at a first pressure (high pressure) for gas blow molding and a second supply source 8b that supplies pressurized gas at a second pressure (medium pressure) lower than the first pressure for gas blow molding, as needed, but is not limited thereto. In this embodiment, the pressurized gas supply source 8 also has a gas discharge section 8c that discharges gas from the gas supply path 7 to depressurize the container after gas blow molding. In this embodiment, the pressurized gas is pressurized air.

[0024] The discharge path 9 opens to the supply port 3d, passes through the nozzle 3, and communicates with the interior of the specified container arranged in the mold 2 and in close contact with the nozzle tip 3a. The discharge path 9 also has a radial discharge path 9a extending radially to the supply port 3d. The tip flow path 14 has a radial discharge port 14c that radially penetrates the seal tip tube 4a when the seal body 4 is in the closed position, connecting the radial discharge path 9a to the tip recess 14a. This radial discharge port 14c also serves as part of the discharge path 9, connecting the radial discharge path 9a to the interior of the specified container arranged in the mold 2 and in close contact with the nozzle tip 3a. The discharge path 9 passes liquid through the tip recess 14a, the radial discharge port 14c, and the radial discharge path 9a in this order. This configuration allows for smooth exhaust before and after (or either) liquid blow molding. The discharge path 9 has a liquid valve 9b that opens and closes the flow path between the suction source 10 and the upstream end of the discharge path 9 (the tip of the tip flow path 14). The liquid valve 9b is built into the nozzle 3 so as to open and close the radial discharge passage 9a, but is not limited to this.

[0025] Furthermore, when the rod 5 is housed within the supply port 3d and the seal body 4 is in the closed position, the suction source 10 sucks the liquid adhering to the nozzle tip 3a, the seal tip tube 4a, and the lower end of the rod 5 through the discharge path 9. In the removal step described below, if there is no need to suck the liquid, such as when there is no concern that the liquid adhering to the nozzle 3 will drip, the configuration may be such that the suction source 10 is not provided.

[0026] In liquid blow molding, when liquid is discharged through the lower end of rod 5 that has been lowered to near the bottom of the container with seal body 4 in the closed position to form a headspace from inside the container that is arranged in mold 2 and has the inner circumferential surface of mouth 12a in close contact with nozzle tip 3a, assisting gas supply source 11 supplies pressurized gas at a third pressure (low pressure) lower than the second pressure through gas supply path 7 into the container to assist the discharge. Assisting gas supply source 11 is useful when a highly viscous liquid that creates high resistance to the liquid flowing through the liquid flow path provided inside rod 5 is used as the content.

[0027] In the liquid blow molding process, when the seal body 4 is in the open position, pressurized liquid is supplied from the pressurized liquid supply source 6 through the liquid supply path 3b into the interior of the specified preform 12 placed in the specified mold 2 and in close contact with the nozzle tip 3a, and the preform 12 is blow-molded into the specified container that conforms to the shape of the cavity 2a of the mold 2.

[0028] In the liquid blow molding process, for example, a prefilling process, a stretching process, a headspace forming process, and a removal process are performed in this order. In the prefilling process, the liquid supply channel 3b is slightly opened by the sealing body 4, or the liquid flow channel of the rod 5 is used to supply liquid into the interior of the preform 12, while air is discharged from the interior of the preform 12 through the discharge channel 9. Alternatively, air may be discharged through the gas supply channel 7 (gas discharge portion 8c of the pressurized gas supply source 8). In the stretching process, the sealing body 4 is moved to the open position to open the liquid supply channel 3b, and the preform 12 is molded into a container by biaxial stretch blow molding using the pressurized liquid and the rod 5. In the headspace forming process, the liquid is discharged from the interior of the container using the liquid flow channel of the rod 5 and the assisting gas supply source 11, forming an appropriate amount of headspace inside the container. In the removal process, the liquid adhering to the nozzle tip 3a, the seal tip tube 4a, and the lower end of the rod 5 is sucked through the discharge path 9 while the nozzle tip 3a is removed from the mouth 12a of the container, thereby preventing the liquid from dripping from the nozzle 3 into the container.

[0029] In the gas blow molding process, when the seal body 4 is in the closed position, pressurized gas is supplied from the pressurized gas supply source 8 through the gas supply path 7 into the inside of the other preform 12 that is placed in the specified molding die 2 or the other molding die 2 and is in close contact with the nozzle tip 3a, and the preform 12 is blow-molded into the other container that conforms to the shape of the cavity 2a of the molding die 2.

[0030] In the gas blow molding process, for example, a medium-pressure blow process using the second pressure, a high-pressure blow process using the first pressure, an exhaust process, and a removal process are performed in this order. In the medium-pressure blow process, biaxially stretch blow molding using pressurized gas is started using the second supply source 8b of the pressurized gas supply source 8 and the rod 5. In the high-pressure blow process, biaxially stretch blow molding using pressurized gas is completed using the first supply source 8a of the pressurized gas supply source 8 and the rod 5. In the exhaust process, high-pressure gas is discharged from the inside of the container through the gas discharge portion 8c of the pressurized gas supply source 8, and the container is depressurized to atmospheric pressure. In the removal process, the nozzle tip 3a is removed from the mouth 12a of the container.

[0031] When contents adhere to the mold 2 (such as the gaps in the opening and closing section) due to the rupture of the preform 12 during liquid blow molding, it is often impossible to know whether the adhered contents have been cleaned off until a container is molded. As described above, the blow molding apparatus 1 of this embodiment, which performs the liquid blow molding process and the gas blow molding process using the same nozzle 3, allows confirmation to be made during gas blow molding instead of liquid blow molding. Furthermore, when mass production is resumed after changing (changing) the type of preform 12 used in liquid blow molding, the mold 2, the pressurized liquid (contents), etc., if the differences in molding conditions between pressurized liquid and pressurized gas are understood in advance, the molding conditions can be set for gas blow molding instead of liquid blow molding.

[0032] Therefore, with the blow molding apparatus 1 of this embodiment, it is no longer necessary to discard the contents used in molding along with the containers for adjustments (checking, setting molding conditions, etc.) when mass production using liquid blow molding is resumed, which improves yield and reduces the effort required for disposal. This is particularly useful when the contents are expensive liquids such as cosmetics.

[0033] The blow molding apparatus 1 of this embodiment is not limited to the above-described usage method, and can also be used in other ways, such as molding a predetermined number of empty containers and supplying them to a subsequent process, and then using the same nozzle 3 to mold a predetermined number of filled containers and supply them to a subsequent process.

[0034] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and the above-described embodiments can be modified in various ways without departing from the gist of the present invention. [Explanation of symbols]

[0035] 1 Blow molding equipment 2 Molding mold 2a cavity 3 nozzles 3a Nozzle tip 3b Liquid supply path 3c sealing surface 3d supply port 4 Seal body 4a Seal tip tube 5 rods 6 Pressurized fluid supply 7 Gas supply line 7a Radial supply path 7b Gas valve 8 Pressurized gas supply source 8a 1st source 8b Second source 8c Gas exhaust section 9 Exhaust channel 9a Radial discharge channel 9b Liquid valve 10 Suction source 11 Assist gas supply source 12 Preform 12a Mouth 12b Stretched part 13. Tank 14 Tip flow channel 14a Tip recess 14b Radial supply port 14c Radial outlet O center axis

Claims

1. a mold having a cavity; a nozzle having a cylindrical nozzle tip, a liquid supply passage extending to a tip of a central opening of the nozzle tip, an annular sealing surface facing the liquid supply passage, and a supply port forming a part of the liquid supply passage and extending from an inner peripheral edge of the sealing surface to the tip of the central opening of the nozzle tip; a seal body that reciprocates in the axial direction between a closed position where it comes into close contact with the seal surface to close the liquid supply passage and an open position where it moves away from the seal surface to open the liquid supply passage; a pressurized liquid supply source that supplies pressurized liquid through the liquid supply path into the interior of a predetermined preform that is placed in the molding die and in close contact with the nozzle tip when the seal body is in the open position, thereby blow-molding the preform into a predetermined container that conforms to the shape of the cavity; a gas supply path that opens to the supply port, passes through the inside of the nozzle, and communicates with the inside of another preform that is in close contact with the nozzle tip; and a pressurized gas supply source that supplies pressurized gas through the gas supply path to the inside of the other preform that is placed in the mold and in close contact with the nozzle tip when the seal body is in the closed position, thereby blow-molding the preform into another container that conforms to the shape of the cavity.

2. a rod extending in an elongated shape in the axial direction radially inside the cylindrical seal body extending in the axial direction and reciprocating in the axial direction; the seal body has a seal tip tube that extends from a portion located on the inner circumferential edge of the seal surface toward a tip of the supply port when the seal body is in the closed position, 2. The blow molding apparatus according to claim 1, wherein the gas supply passage has a radial supply passage extending radially toward the supply port, and a tip flow passage that is configured by a recess provided in one or both of the nozzle and the seal tip tube, and that connects the radial supply passage to the interior of the other preform that is placed in the molding die and in close contact with the nozzle tip.

3. a discharge path that opens to the supply port, passes through the inside of the nozzle, and communicates with the inside of the predetermined container that is disposed in the mold and in close contact with the tip of the nozzle; a suction source that draws the liquid through the discharge passage when the seal is in the closed position; the discharge path has a radial discharge path extending in the radial direction toward the supply port, The blow molding apparatus according to claim 2, wherein the tip flow path connects the radial discharge path to the interior of the specified container arranged in the mold and in close contact with the nozzle tip, and also serves as part of the discharge path.

4. the radial supply passage and the radial discharge passage each open to the supply port, 4. The blow molding apparatus according to claim 3, wherein the tip flow path has a tip recess provided on the inner surface of the seal tip tube and extending to the tip of the seal tip tube, a radial supply port that penetrates the seal tip tube in the radial direction to connect the radial supply path to the tip recess when the seal body is in the closed position, and a radial discharge port that penetrates the seal tip tube in the radial direction to connect the radial discharge path to the tip recess when the seal body is in the closed position.

5. A blow molding method using the blow molding apparatus according to any one of claims 1 to 4, a liquid blow molding process in which the pressurized liquid is supplied from the pressurized liquid supply source through the liquid supply path into the interior of the predetermined preform that is placed in the mold and in close contact with the nozzle tip when the seal body is in the open position, thereby blow-molding the preform into the predetermined container that conforms to the shape of the cavity; and a gas blow molding step of blow-molding the preform into the other container that conforms to the shape of the cavity by supplying the pressurized gas from the pressurized gas supply source through the gas supply path into the inside of the other preform that is placed in the mold and in close contact with the nozzle tip when the seal body is in the closed position.

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