Manufacturing method of liquid-filled container

Abstract

To provide a method for manufacturing a liquid-containing container which can prevent a device of a post process from contaminated by a liquid leaked from the liquid-containing container.SOLUTION: A method for manufacturing a liquid-containing container that manufactures a liquid-containing container C storing a content liquid from a synthetic resin-made preform 2 includes: a blow molding step of supplying a pressurized liquid to the preform 2 arranged in a mold 10, and blow-molding the preform 2; a mold opening step of opening the mold 10 so as to take out the liquid-containing container C after the blow-molding step; and a liquid leakage detection step of detecting, by the detector 50, the liquid L dripping down from a cavity 11 of the opened mold 10 before the liquid-containing container C is taken out of the mold 10 after the mold opening step, thereby detecting liquid leakage from the liquid-containing container C.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing a liquid-filled container, which produces a liquid-filled container containing a liquid content, from a preform made of synthetic resin. [Background technology]

[0002] Synthetic resin containers, such as polypropylene (PP) bottles and polyethylene terephthalate (PET) bottles, are used to store various liquid contents, such as beverages, cosmetics, medicines, detergents, and toiletries such as shampoo. Such containers are generally manufactured by blow molding a preform made of the above-mentioned thermoplastic synthetic resin.

[0003] As a blow molding method for molding a preform into a container, liquid blow molding is known in which a pressurized liquid is used instead of pressurized air as the pressurized medium to be supplied inside the preform. For example, Patent Document 1 describes a liquid blow molding method in which a synthetic resin preform is placed in a mold for blow molding, and pressurized liquid is supplied from a pressurized liquid supply source through a nozzle unit into the preform, thereby molding the preform into a container of a predetermined shape that fits the cavity of the mold.

[0004] According to the liquid blow molding method as described above, by using the content liquid to be filled in the container as the final product as the liquid to be supplied to the preform, it is possible to manufacture a liquid-filled container containing the content liquid by simultaneously molding the container and filling the container with the content liquid. Therefore, according to this method of manufacturing a liquid-filled container using liquid blow molding, it is possible to omit the step of filling the container with the content liquid after molding, and to manufacture a liquid-filled container at low cost. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-119099 A Summary of the Invention [Problem to be solved by the invention]

[0006] In conventional methods for manufacturing liquid-filled containers using liquid blow molding, the container is filled with liquid after molding. Therefore, if the container is torn or has a hole such as a pinhole during blow molding for some reason, there is a risk that the liquid leaking from the hole in the container will contaminate the equipment during the capping process, labeling process, transport process, etc. that are performed after the blow molding process, and production will be halted while the contamination is removed by cleaning or the like.

[0007] The present invention has been made in consideration of such problems, and its purpose is to provide a method for manufacturing liquid-filled containers that can prevent liquid leaking from the liquid-filled container from contaminating downstream equipment. [Means for solving the problem]

[0008] The method for manufacturing a liquid-filled container of the present invention is a method for manufacturing a liquid-filled container containing a liquid content from a preform made of synthetic resin, and includes a blow molding process for supplying pressurized liquid to the preform placed in a mold to blow mold the preform, a mold opening process for opening the mold after the blow molding process to remove the liquid-filled container, and a liquid leakage detection process for detecting liquid leakage from the liquid-filled container by detecting liquid dripping from the liquid-filled container with a detector after the mold opening process and before the liquid-filled container is removed from the mold. an apparatus stopping step of automatically or manually stopping operation of a liquid-filled container manufacturing apparatus that manufactures the liquid-filled container when liquid leakage from the liquid-filled container is detected in the liquid leakage detection step; The present invention is characterized by having the following.

[0010] In the above-described configuration, the method for producing a liquid-filled container of the present invention preferably further comprises a rod stretching step of stretching the preform in the axial direction by a stretching rod before or during the blow molding step.

[0011] In the above-described configuration, the manufacturing method for a liquid-filled container of the present invention preferably further includes a prefilling step prior to the blow molding step, in which liquid is supplied to the inside of the preform at a pressure sufficient not to stretch the preform, thereby filling the inside of the preform with liquid.

[0012] In the above-described configuration, the manufacturing method of the liquid-filled container of the present invention preferably further includes a suck-back step of sucking out a portion of the liquid content from the liquid-filled container after the blow molding step and before the mold opening step.

[0013] In the method for manufacturing a liquid-filled container of the present invention, in the above-mentioned configuration, the mold has a pair of body molds that open to the left and right and a bottom mold that moves downward to open, and it is preferable that the detector is a photoelectric sensor having a light-projector and a light-receiver and detecting the liquid below the cavity of the mold.

[0014] In the manufacturing method for liquid-filled containers of the present invention, in the above-mentioned configuration, the mold used is one having a pair of body molds that open to the left and right and a bottom mold that moves downward to open, and when the mold opens, a dish member is provided that is placed between the pair of body molds and the bottom mold, and the detector is preferably one that is placed on the dish member and detects liquid that has accumulated in the dish member. Effect of the Invention

[0015] According to the present invention, it is possible to provide a method for manufacturing a liquid-filled container that is capable of preventing a downstream device from being contaminated by liquid leaking from the liquid-filled container. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram showing an example of a liquid-filled container manufacturing apparatus capable of carrying out a liquid-filled container manufacturing method according to an embodiment of the present invention. [Diagram 2]2 is a diagram showing a state in which a pre-filling step is being performed in the liquid-filled container manufacturing apparatus shown in FIG. 1. [Diagram 3] FIG. 2 is a diagram showing a state in which a rod-drawing step and a blow-molding step are being performed in the liquid-filled container manufacturing apparatus shown in FIG. [Figure 4] 2 is a diagram showing a state in which a suck-back process is being performed in the liquid-filled container manufacturing apparatus shown in FIG. 1. [Diagram 5] 2 is a diagram showing a state in which a head space is provided in the liquid-filled container in the liquid-filled container manufacturing apparatus shown in FIG. 1. [Figure 6] 2 is a diagram showing a state in which a liquid leakage detection process is being performed in the liquid-filled container manufacturing apparatus shown in FIG. 1. [Figure 7] 1A to 1C are process diagrams showing an example of a procedure for a method for manufacturing a liquid-filled container according to an embodiment of the present invention. [Figure 8] 1. FIG. 4 is a diagram showing a state in which the liquid leakage detection step is being performed in another form in the liquid-filled container manufacturing apparatus shown in FIG. [Figure 9] 7 is a diagram showing a modified example of the liquid-filled container manufacturing apparatus shown in FIG. 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The present invention will now be described in more detail with reference to the drawings.

[0018] A method for manufacturing a liquid-filled container according to one embodiment of the present invention can be carried out using an apparatus 1 for manufacturing a liquid-filled container having a configuration shown in FIG.

[0019] The liquid-filled container manufacturing apparatus 1 manufactures a liquid-filled container C (see FIG. 5) that contains a content liquid from a synthetic resin preform 2. As the liquid (content liquid) L to be contained in the liquid-filled container C, various liquids can be used, such as beverages, cosmetics, medicines, detergents, and toiletries such as shampoo.

[0020] The preform 2 can be made of a synthetic resin material having thermoplastic properties, such as polypropylene (PP) or polyethylene terephthalate (PET), and is shaped like a bottomed cylinder having a cylindrical mouth 2a which is the open end, a cylindrical body 2b connected to the mouth 2a, and a hemispherical bottom 2c which closes the lower end of the body 2b.

[0021] Although not shown in detail, an engagement protrusion is provided on the outer wall surface of the mouth 2a for attaching a closure cap (not shown) to the mouth 2a of the liquid-filled container C after molding by plugging (undercut engagement). Note that a male screw may be provided on the outer wall surface of the mouth 2a instead of the engagement protrusion, and the closure cap may be attached to the mouth 2a by screw connection.

[0022] The liquid-filled container manufacturing apparatus 1 has a blow molding die 10. The die 10 has a cavity 11 shaped to correspond to the final shape of the liquid-filled container C, such as a bottle shape. The cavity 11 opens upward on the top surface of the die 10. The preform 2 is attached to the die 10 with the body 2b and bottom 2c disposed inside the cavity 11 of the die 10 and the mouth 2a protruding upward from the die 10.

[0023] The mold 10 is equipped with a pair of body molds 12a, 12b that open to the left and right, and a bottom mold 12c that moves downward relative to the body molds 12a, 12b to open.After the preform 2 has been molded into a liquid-filled container C, the pair of body molds 12a, 12b are opened to the left and right while the bottom mold 12c is moved downward to open, while the mouth portion 2a is held by a conveying device (not shown), so that the liquid-filled container C can be removed from the mold 10 by the conveying device.

[0024] Above the mold 10, a nozzle unit 20 for supplying pressurized liquid L into the inside of the preform 2 is provided.

[0025] The nozzle unit 20 has a main body block 21, and a supply path 21a for the liquid L is provided inside the main body block 21. A supply port 21b for the liquid L, which is connected to the supply path 21a and opens downward, is provided at the lower end of the main body block 21. Furthermore, a supply port 21c, which is connected to the supply path 21a, is provided at the side of the main body block 21.

[0026] A seal body 22 is provided inside the main body block 21. The seal body 22 moves up and down inside the supply passage 21a to open and close the supply port 21b.

[0027] Further, the main body block 21 is provided with an extension rod 23. The extension rod 23 passes through the seal body 22 and can move up and down so as to protrude downward from the supply port 21b.

[0028] A pressurized liquid supply source 30 is connected to the supply port 21c via a pipe 24. The pressurized liquid supply source 30 is composed of a plunger pump equipped with a cylinder 31 and a piston (plunger) 32, and can supply liquid L pressurized to a predetermined pressure to the supply path 21a.

[0029] The pressurized liquid supply source 30 is not limited to a plunger pump, and various configurations can be used as long as they can supply the liquid L pressurized to a predetermined pressure to the supply path 21a.

[0030] A tank 40 is connected to the pressurized liquid supply source 30 via piping 25. The tank 40 stores liquid L, and supplies the liquid L to the pressurized liquid supply source 30 through the piping 25. The piping 25 is provided with an on-off valve 26 that opens and closes between the pressurized liquid supply source 30 and the tank 40.

[0031] The nozzle unit 20 is movable vertically relative to the mold 10. When the nozzle unit 20 descends to the lower stroke end, the lower end of the main body block 21 engages with the mouth portion 2a of the preform 2, and the supply port 21b is liquid-tightly connected to the internal space of the preform 2.

[0032] The liquid-filled container manufacturing apparatus 1 is equipped with a detector 50. In the case where the liquid-filled container C is leaking inside the cavity 11 of the mold 10 due to a hole such as a tear or a pinhole occurring during blow molding, the detector 50 can detect the liquid L leaking from the liquid-filled container C and dripping downward when the mold 10 is opened.

[0033] In this embodiment, a photoelectric sensor having a light projector 51 and a light receiver 52 is used as the detector 50. In this case, the light projector 51 is disposed below one of the body molds 12a and offset laterally from the bottom mold 12c, and the light receiver 52 is disposed below the other body mold 12b and offset laterally from the bottom mold 12c. The light projector 51 is configured to irradiate a light beam having a width equal to or greater than the outer diameter of the liquid-filled container C or the inner diameter of the cavity 11 toward the light receiver 52. The direction of the light beam irradiated from the light projector 51 is set to a direction passing directly below the liquid-filled container C, so that the light beam is irradiated along a path including the projection plane of the liquid-filled container C as viewed from the axial direction of the liquid-filled container C. The light receiver 52 detects that the liquid L is dripping from the liquid-filled container C when the light beam irradiated from the light projector 51 is blocked by the liquid L and cannot be received, or when the light receiving sensitivity changes.

[0034] As the detector 50, various sensors can be used as long as they can detect the liquid L dripping from the liquid-filled container C, such as a laser sensor that uses a laser instead of a light beam, or a light absorption sensor that utilizes the property of light being absorbed by water molecules, instead of the photoelectric sensor described above.

[0035] The liquid-filled container manufacturing apparatus 1 has a control unit 60 that is constituted by, for example, a microcomputer. The nozzle unit 20, the pressurized liquid supply source 30, the on-off valve 26, the mold 10, and the detector 50 are each connected to the control unit 60, and their operations are integrally controlled by the control unit 60.

[0036] The liquid-filled container manufacturing apparatus 1 also has pre-processing devices 61 such as a heating device that performs a heating step of heating the preform 2 to a predetermined temperature, post-processing devices 62 such as a capper device that performs a capping step of attaching a cap to the mouth 2a of the liquid-filled container C after blow molding and a labeler device that performs a labeling step of attaching a label to the liquid-filled container C, and a transport device 63 that transports the preform 2 or the liquid-filled container C between each process. The pre-processing devices 61, post-processing devices 62 and transport device 63 are also connected to the control unit 60, and their operations are controlled in an integrated manner.

[0037] 2 to 5, the control unit 60, the pre-processing device 61, the post-processing device 62, and the transport device 63 are omitted.

[0038] Next, a method for manufacturing a liquid-filled container C containing a liquid (content liquid) L therein from a synthetic resin preform 2 using the liquid-filled container manufacturing apparatus 1 configured as described above (a method for manufacturing a liquid-filled container according to this embodiment) will be described.

[0039] First, as shown in step S1 in Fig. 7, the preform 2 heated to a predetermined temperature (e.g., 80°C to 150°C) at which the preform 2 exhibits extensibility in the front-end process device 61 is inserted into the mold 10, and then, as step S2, the mold 10 is closed and the preform 2 is placed in the mold 10 as shown in Fig. 1. At this time, the mouth portion 2a of the preform 2 is open, so the inside of the preform 2 is filled with air.

[0040] Next, in step S3, the nozzle unit 20 is lowered to connect the supply port 21b to the mouth portion 2a of the preform 2 as shown in FIG.

[0041] Next, in this embodiment, a pre-filling process is performed as step S4, in which the liquid L is supplied to the inside of the preform 2 at a pressure that does not stretch the preform 2, to fill the inside of the preform 2 with the liquid L. More specifically, in the pre-filling process, as shown in FIG. 2, the nozzle unit 20 is lowered to connect the supply port 21b to the mouth portion 2a of the preform 2, and then the on-off valve 26 is closed and the seal body 22 is opened, and the pressurized liquid supply source 30 is operated at a low speed to supply the liquid L from the supply port 21b to the inside of the preform 2 through the piping 24 and the supply path 21a, so that the inside of the preform 2 is filled with the liquid L. At this time, the air inside the preform 2 is replaced with the liquid L and is exhausted to the outside from an exhaust path not shown. In the pre-filling process, it is preferable that the preform 2 is not stretched by the pressure of the liquid L and remains in its original shape, but it may be slightly stretched.

[0042] Next, in step S5, a blow molding process by main fill is performed. In the blow molding process, the on-off valve 26 is closed, the seal body 22 is opened, and the pressurized liquid supply source 30 is operated to perform main fill, supplying liquid L pressurized to a predetermined pressure (higher than the pressure in the prefill process) from the supply port 21b through the piping 24 and the supply path 21a into the inside of the preform 2, and as shown in FIG. 3, the body 2b and the bottom 2c of the preform 2 are stretched to blow mold the liquid-filled container C having a shape that fits the cavity 11.

[0043] In this embodiment, a pre-filling process is performed before the blow molding process, thereby preventing air inside the preform 2 from becoming entrained in the liquid L during the blow molding process, causing bubbling, etc., and preventing air from becoming mixed into the liquid L inside the liquid-filled container C formed by the blow molding process.

[0044] The blow molding step may be performed without performing the prefilling step.

[0045] In this embodiment, a rod stretching step is performed in the blow molding step. In the rod stretching step, the stretch rod 23 is moved downward to stretch the body portion 2b of the preform 2 in the axial direction by the stretch rod 23. The rod stretching step can also be configured to be performed before the blow molding step. By configuring the rod stretching step to be performed while performing the blow molding step as in this embodiment, it is possible to perform biaxial stretch blow molding in which the preform 2 is stretched in the axial direction by the stretch rod 23 while being blow molded by the pressure of the liquid L. This allows the preform 2 to be molded into a liquid-filled container C of a predetermined shape with greater precision.

[0046] It is also possible to blow mold the preform 2 into the liquid-filled container C only through the blow molding process, without carrying out the rod stretching process.

[0047] In this embodiment, after the blow molding process and before the mold 10 is opened, a suck-back process is performed as step S6 to suck out a part of the liquid (content liquid) L from the liquid-filled container C to prepare the head space. In the suck-back process, as shown in FIG. 4, the on-off valve 26 is closed, and the pressurized liquid supply source 30 is operated in the reverse direction while the seal body 22 is open, so that a part of the liquid L contained in the liquid-filled container C is sucked back from the supply port 21b to the supply path 21a. The amount of liquid L sucked back is the amount obtained by subtracting the volume of the part of the stretch rod 23 contained in the liquid-filled container C from the amount corresponding to the head space. When the suck-back process is performed, the body of the liquid-filled container C becomes concave in accordance with the amount of the liquid L sucked back, and a gap is generated between the body and the inner surface of the cavity 11 of the mold 10.

[0048] 5, after the supply port 21b is closed by the seal body 22, the nozzle unit 20 and the stretching rod 23 are raised. When the nozzle unit 20 is raised and the supply port 21b is separated from the mouth portion 2a of the liquid-containing container C, outside air is introduced into the liquid-containing container C, and a head space H is formed in the liquid-containing container C. The amount of the head space H is the total amount of the liquid sucked back in the suck-back process and the volume of the portion of the stretching rod 23 that was contained in the liquid-containing container C.

[0049] In addition, the suck back step may not be performed. In this case, the head space H may be provided in the liquid-containing container C by another method, such as providing the head space H only with the volume of the stretch rod 23.

[0050] Next, in order to remove the liquid-filled container C, a mold opening process is performed in step S8, in which the pair of body molds 12a, 12b are opened to the left and right, and the bottom mold 12c is moved downward to open the mold 10. Then, in step S9, the liquid-filled container C is removed from the mold 10 using the conveying device 63 and conveyed to the post-processing device 62. In the mold opening process, the pair of body molds 12a, 12b may be opened and then the bottom mold 12c may be moved downward to open, or the bottom mold 12c may be moved downward to open and then the pair of body molds 12a, 12b may be opened. In the case where the bottom mold 12c is moved downward to open and then the pair of body molds 12a, 12b is opened, the detector 50 may be activated before the pair of body molds 12a, 12b are opened.

[0051] Here, in the manufacturing method for a liquid-filled container of this embodiment, a liquid leakage detection step is performed after the mold opening step and before the liquid-filled container C is removed from the mold 10, in which the detector 50 detects the liquid L dripping from the liquid-filled container C. In this embodiment, as shown as step S10 in Figures 6 and 7, after the mold 10 is opened in step S8 and before the liquid-filled container C is removed from the mold 10 in step S9. By performing the liquid leakage detection step, even if the liquid-filled container C is torn or has a hole such as a pinhole during the blow molding step, the detector 50 can detect the liquid L dripping from the liquid-filled container C when the mold 10 is opened, and leakage of the liquid L from the liquid-filled container C can be detected.

[0052] In the liquid leakage detection process, if the detector 50 does not detect liquid L, the control unit 60 determines that there is no liquid leakage from the liquid-filled container C, and returns to step S9, where the liquid-filled container C is removed from the mold 10 by the transport device 63 and transported to the subsequent process, and the subsequent process is carried out by the subsequent process device 62.

[0053] On the other hand, if a hole such as a tear or a pinhole occurs in the liquid-filled container C during the blow molding process, the liquid L leaking from the liquid-filled container C will drip downward when the mold 10 is opened, as shown in Fig. 6, and this dripping of the liquid L from the liquid-filled container C will be detected by the detector 50. That is, the liquid L dripping from the liquid-filled container C blocks the light beam irradiated from the light projector 51 and received by the light receiver 52, and the dripping of the liquid L from the liquid-filled container C is detected by the detector 50. Therefore, if a hole such as a tear or a pinhole occurs in the liquid-filled container C during the blow molding process and causes liquid leakage from the liquid-filled container C, the leakage of the liquid L from the liquid-filled container C will be detected by the detector 50 in step S10.

[0054] In this embodiment, when leakage (liquid leakage) of the liquid L from the liquid-filled container C is detected in the liquid leakage detection step, an apparatus stopping step is performed. In the apparatus stopping step, as shown in step S11, the operation of the liquid-filled container manufacturing apparatus 1 that manufactures the liquid-filled container C, that is, the operation of the devices constituting the liquid-filled container manufacturing apparatus 1, such as the nozzle unit 20, the pressurized liquid supply source 30, the pre-process device 61, the post-process device 62, and the conveying device 63, is automatically stopped without removing the liquid-filled container C from the mold 10. At this time, if the liquid-filled container manufacturing apparatus 1 includes a plurality of molds 10 and is configured to be able to individually control the lines corresponding to the respective molds 10, it is possible to stop only the line of the mold 10 that has caused the liquid leakage, and allow the lines of the other molds 10 to continue operating.

[0055] Then, after the operation of the manufacturing apparatus 1 for liquid-filled containers is stopped, the area contaminated by the liquid leakage is cleaned in step S12, and after the cleaning is completed, the manufacturing apparatus 1 for liquid-filled containers is restarted.

[0056] As described above, in the manufacturing method for a liquid-filled container of this embodiment, a liquid leakage detection step is performed after the mold opening step and before the liquid-filled container C is removed from the mold 10, by detecting the liquid L dripping from the liquid-filled container C with the detector 50, so that liquid leakage from the liquid-filled container C can be detected before the liquid-filled container C is removed from the mold 10. Therefore, even if a hole such as a tear or a pinhole occurs in the liquid-filled container C during blow molding for some reason, liquid leakage due to the hole can be detected before the liquid-filled container C is removed from the mold 10. Therefore, after liquid leakage is detected, the manufacturing apparatus 1 for a liquid-filled container can be manually stopped, for example, to prevent the downstream process device 62 and the conveying device 63 from being contaminated by the liquid L leaking from the liquid-filled container C.

[0057] Furthermore, in the manufacturing method for a liquid-filled container of this embodiment, liquid L dripping from the liquid-filled container C can be detected by a detector 50 installed outside the mold 10, so that liquid leakage from the liquid-filled container C can be detected without complicating the configuration of the mold 10.

[0058] Furthermore, in this embodiment, when leakage from the liquid-filled container C is detected in the liquid leakage detection process, the operation of the liquid-filled container manufacturing apparatus 1 that manufactures the liquid-filled container C is automatically stopped, so that it is possible to more reliably prevent the downstream process apparatus 62 and the conveying apparatus 63 from being contaminated by the liquid L leaking from the liquid-filled container C in downstream processes such as the capping process, labeling process, and conveying process. Furthermore, by preventing the downstream process apparatus 62 and the conveying apparatus 63 from being contaminated by the liquid L, it is possible to minimize the impact of production being stopped while the contamination is removed by cleaning or the like.

[0059] Furthermore, in this embodiment, a rod stretching step is performed before or during the blow molding step, in which the preform 2 is stretched in the axial direction by the stretch rod 23, so that the preform 2 can be molded into a liquid-filled container C of a predetermined shape with greater precision by biaxial stretch blow molding. Furthermore, by using the stretch rod 23, the preform 2 is stretched to a high degree during blow molding, so that the liquid-filled container C is more likely to have holes such as tears and pinholes during blow molding. Even in this case, however, it is possible to detect liquid leakage due to the holes before the liquid-filled container C is removed from the mold 10, and reliably prevent the post-processing device 62 and the transport device 63 from being contaminated by the liquid L.

[0060] Furthermore, in this embodiment, a pre-filling process is performed before the blow molding process, in which the liquid L is supplied to the inside of the preform 2 at a pressure that does not stretch the preform 2, thereby filling the inside of the preform 2 with the liquid L. This prevents air inside the preform 2 from being drawn into the liquid L and causing bubbles during the blow molding process, and prevents air from being mixed into the liquid L inside the liquid-filled container C formed by the blow molding process. In addition, by performing the pre-filling process, the preform 2 is cooled by the liquid L, which increases the possibility of holes such as breaks and pinholes being formed in the liquid-filled container C during blow molding. Even in this case, however, it is possible to reliably prevent the post-processing device 62 and the conveying device 63 from being contaminated by the liquid L by detecting the liquid leakage due to the hole before the liquid-filled container C is removed from the mold 10.

[0061] Furthermore, in this embodiment, a suck-back process is performed after the blow molding process and before the mold opening process, in which a portion of the liquid (content liquid) L is sucked out from the liquid-filled container C, so that an appropriate head space H can be easily formed in the liquid-filled container C. Also, when the suck-back process is performed, the body of the liquid-filled container C is recessed, creating a gap between the body and the inner surface of the body mold 12a. Therefore, if a hole such as a tear or a pinhole occurs in the liquid-filled container C during blow molding, the liquid L leaking from the hole will accumulate in the gap between the body of the liquid-filled container C and the inner surface of the body mold 12a, making it easier for the detector 50 to detect the liquid L when the mold 10 is opened, so that the liquid leakage can be detected more reliably in the liquid leakage detection process.

[0062] Furthermore, in this embodiment, the mold 10 used has a pair of body molds 12a, 12b that open to the left and right and a bottom mold 12c that moves downward to open, and the detector 50 is a photoelectric sensor that has a light projector 51 and a light receiver 52 and detects the liquid L below the cavity 11, so that the liquid L leaking from the liquid-filled container C and dripping downward can be reliably detected with a simple configuration.

[0063] The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit and scope of the present invention.

[0064] For example, in the above embodiment, the light projector 51 constituting the detector 50 is disposed below one of the body molds 12a, and the light receiver 52 constituting the detector 50 is disposed below the other body mold 12a, so that when the mold 10 is opened, a light beam is emitted to the lower side of the pair of body molds 12a, 12b to detect the liquid L, but the light projector 51 constituting the detector 50 may be disposed on the side of the body mold and the light receiver 52 constituting the detector 50 may be disposed on the opposite side of the body mold, so that when the mold 10 is opened, the light projected by the light projector 51 is received by the light receiver 52 through the gap between the pair of body molds 12a, 12b. In this case, when the mold 10 is opened, the light projected by the light projector 51 is received by the light receiver 52 through the gap between the pair of body molds 12a, 12b, so that the detection of the liquid L can be automatically started at the same time as the mold 10 is opened. Furthermore, as long as the detector 50 is operating when the mold 10 is opened during the mold opening process, the timing at which the detector starts operating can be set arbitrarily, or the detector 50 can be set to operate at all times.

[0065] 8, the liquid-filled container manufacturing apparatus 1 may be provided with a dish member 53 that is inserted from the side of the mold 10 and disposed between the pair of body molds 12a, 12b and the bottom mold 12c when the mold 10 is opened, and a water leakage sensor that is disposed on the dish member 53 and detects liquid accumulated in the dish member 53 may be used as the detector 50 instead of a photoelectric sensor. In this case, in the liquid leakage detection step, the liquid L leaking from the liquid-filled container C drips from the liquid-filled container C and accumulates in the dish member 53, and the accumulated liquid L is detected by the detector 50, thereby detecting the liquid leakage from the liquid-filled container C. With this configuration, the liquid L can be reliably detected while preventing the bottom mold 12c from being contaminated by the liquid L dripping from the liquid-filled container C.

[0066] Furthermore, for example, as shown in Fig. 9, the detector 50 may be disposed inside a portion of the mold 10 below the cavity 11. In this case, as shown in Fig. 9, the light projector 51 may be embedded below the cavity 11 of one body mold 12a and exposed at the parting surface with the bottom mold 12c, and the light receiver 52 may be embedded below the cavity 11 of the other body mold 12b and exposed at the parting surface with the bottom mold 12c.

[0067] Furthermore, in the above embodiment, the liquid leakage detection process is performed after both the pair of body molds 12a, 12b and the bottom mold 12c of the mold 10 are opened in the mold opening process, but the liquid leakage detection process may also be performed in an open state by moving only the bottom mold 12c downward before opening the pair of body molds 12a, 12b.

[0068] Furthermore, in the above embodiment, in addition to the blow molding step, the pre-filling step, the rod stretching step, and the suck-back step are performed, but these steps do not necessarily have to be performed.

[0069] Furthermore, the method for manufacturing a liquid-filled container can also be carried out using an apparatus other than the above-mentioned apparatus 1 for manufacturing a liquid-filled container. [Explanation of symbols]

[0070] 1. Liquid container manufacturing equipment 2 Preform 2a Mouth 2b Torso 2c bottom 10. Mold 11 Cavity 12a Body mold 12b Body mold 12c bottom type 20 Nozzle unit 21 Body block 21a Supply route 21b Supply port 21c Supply Port 22 Seal body 23 Extension rod 24 Piping 25 Piping 26 On-off valve 30 Pressurized Liquid Supply Source 31 Cylinder 32 Piston 40 Tank 50 Detector 51 Floodlight 52 Receiver 53 Plate parts 60 Control section 61 Front-end equipment 62 Post-process equipment 63 Transport Equipment C. Liquid container L liquid H Headspace

Claims

1. A method for manufacturing a liquid-filled container, which manufactures a liquid-filled container containing a liquid content from a synthetic resin preform, comprising the steps of: a blow molding step of blow molding the preform by supplying a pressurized liquid to the preform placed in a mold; a mold opening step of opening the mold to remove the liquid-filled container after the blow molding step; a liquid leakage detection step of detecting liquid leakage from the liquid-containing container by detecting liquid dripping from the liquid-containing container with a detector after the mold opening step and before removing the liquid-containing container from the mold; A method for manufacturing a liquid-filled container, characterized in that it includes an apparatus stop process for automatically or manually stopping operation of a liquid-filled container manufacturing apparatus that manufactures the liquid-filled container when liquid leakage from the liquid-filled container is detected in the liquid leakage detection process.

2. 2. The method for producing a liquid-filled container according to claim 1, further comprising a rod stretching step of stretching the preform in an axial direction by a stretching rod before or during the blow molding step.

3. 3. The method for manufacturing a liquid-filled container according to claim 1, further comprising a prefilling step, prior to the blow molding step, of supplying liquid to the inside of the preform at a pressure not sufficient to stretch the preform, thereby filling the inside of the preform with liquid.

4. The method for manufacturing a liquid-filled container according to any one of claims 1 to 3, further comprising a suck-back process for sucking out a portion of the liquid content from the liquid-filled container after the blow molding process and before the mold opening process.

5. The mold used has a pair of body molds that open to the left and right and a bottom mold that moves downward to open, A method for manufacturing a liquid-filled container described in any one of claims 1 to 4, wherein the detector is a photoelectric sensor having a light emitter and a light receiver, and detecting the liquid below the cavity of the mold.

6. The mold used has a pair of body molds that open to the left and right and a bottom mold that moves downward to open, providing a dish member that is disposed between the pair of body molds and the bottom mold when the molds are opened; 5. The method for manufacturing a liquid-filled container according to claim 1, wherein the detector is disposed on the dish member and detects the liquid accumulated in the dish member.

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