Patent Publication Number: US-2019193322-A1

Title: Container manufacturing method

Description:
TECHNICAL FIELD 
     This disclosure relates to a container manufacturing method of manufacturing a resin container, and in particular to a method of manufacturing a container of a predetermined shape by liquid blow molding a resin preform. 
     BACKGROUND 
     Resin containers, typical examples of which are oriented polypropylene (OPP) bottles and polyethylene terephthalate (PET) bottles, are used for a variety of applications such as beverages, food products, cosmetic products or the like. Such a container is generally manufactured by manufacturing a bottomed tubular preform through injection molding or compression molding of a thermoplastic resin, heating the preform to temperatures at which stretching effect can be expressed, and molding the heated preform into a predetermined shape through blow molding using a mold for blow molding. 
     As blow molding of a preform, liquid blow molding in which blow molding is performed by feeding a pressurized liquid instead of a pressurized air into a preform is known. In the liquid blow molding, as a liquid used for blow molding, content liquid such as beverages, cosmetic products and pharmaceutical products to be filled in a container as an end product is used. Thus the step of filling the content liquid into a container may be omitted, and the manufacturing process and the configuration of the manufacturing device may be simplified. 
     As a manufacturing method of a resin container including the above described liquid blow molding, a method of blow molding a plurality of preforms simultaneously by using a batch-type mold provided with a plurality of cavities disposed in series is known (see, for example, PTL 1). 
     In the above described manufacturing method, a plurality of preforms disposed in series at predetermined pitches are respectively fed into mold cavities in an opened state by a transfer device or the like and are clamped. After that, a pressurized liquid is fed from a nozzle unit located on top of the mold to a preform placed in each cavity, and liquid blow molding is performed. Subsequently the mold is opened and a container after blow molding is ejected by a transfer device or the like. 
     CITATION LIST 
     Patent Literature 
     PTL 1: JP2016032924A 
     SUMMARY 
     Technical Problem 
     In the above described container manufacturing method, a nozzle unit or the like configured to fill a liquid is disposed on top of a mold for blow molding. Thus, for example, before an ejection step of ejecting a mold from a container, it is difficult to perform a decoration step of inserting a label bearing characters or designs into a cavity from the top of the mold and decorating the outer surface of the container and a cap attaching step of attaching a cap to a mouth of the container from the top of the container that is held in the mold. Further, when a container after blow molding is ejected from the cavity of the mold, the ejecting direction and method are limited due to the presence of a nozzle unit or the like. Thus there is still room for improvement in terms of increase in container manufacturing efficiency. 
     Therefore this disclosure is to propose a resin container manufacturing method that allows, in a resin container manufacturing method by liquid blow molding using a batch-type mold, to increase the container manufacturing efficiency. 
     Solution to Problem 
     The disclosed container manufacturing method is a container manufacturing method of manufacturing a resin container, the method including:
         a preform feed step of feeding a preform formed into a bottomed tubular shape by a resin material into a cavity of a batch-type mold for blow molding;   a liquid blow step of filling a pressurized liquid into the preform disposed in the cavity to perform blow molding; and   an ejection step of ejecting a container after blow molding from the cavity, wherein   the method further includes a mold slide step of sliding the mold for blow molding to a slide position that is different from a position of the mold for blow molding in the liquid blow step.       

     It is to be noted that, in the disclosed container manufacturing method, preferably, the mold for blow molding has a plurality of the cavities disposed in series. 
     Further, in the disclosed container manufacturing method, preferably, the method includes a decoration step of applying a decoration to an outer surface of the container with the mold for blow molding located at the slide position. 
     Further, in the disclosed container manufacturing method, preferably, the method includes a cap attaching step of attaching a cap to a mouth of the container with the mold for blow molding located at the slide position. 
     Further, in the disclosed container manufacturing method, preferably, the ejection step is performed with the mold for blow molding located at the slide position. 
     Further, in the disclosed container manufacturing method, preferably, a slide direction of the mold for blow molding in the mold slide step is orthogonal to a transfer direction of the preform in the preform feed step. 
     Further, in the disclosed container manufacturing method, preferably, the slide direction of the mold for blow molding in the mold slide step is orthogonal to a transfer direction of a container after blow molding in the ejection step. 
     Further, in the disclosed container manufacturing method, preferably, the liquid blow step is performed by alternately using two of the molds for blow molding, wherein
         while one of the molds for blow molding is located at a first slide position, the other mold for blow molding performs the liquid blow step; and   while the other mold for blow molding is located at a second slide position, the one of the molds for blow molding performs the liquid blow step.       

     Advantageous Effect 
     According to this disclosure, in a method of manufacturing a resin container by liquid blow molding using a batch-type mold, a manufacturing method of resin container that enables a container manufacturing efficiency to be increased can be provided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings: 
         FIG. 1  is a schematic planar view for illustrating a container manufacturing method according to an embodiment of this disclosure; 
         FIG. 2  is a diagram illustrating an order of each step of the container manufacturing method according to the embodiment of this disclosure; 
         FIG. 3  is a diagram illustrating an order of each step of the container manufacturing method according to another embodiment of this disclosure; 
         FIG. 4  is a diagram illustrating an order of each step of a container manufacturing method according to still another embodiment of this disclosure; 
         FIG. 5  is a schematic planar view for illustrating a container manufacturing method according to yet another embodiment of this disclosure; 
         FIG. 6  is a diagram illustrating an order of each step of the container manufacturing method according to the embodiment in  FIG. 5 ; 
         FIG. 7  is a schematic planar view for illustrating a container manufacturing method according to further embodiment of this disclosure; 
       and 
         FIG. 8  is a diagram illustrating an order of each step of the container manufacturing method according to the embodiment in  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION 
     This disclosure will be illustrated in more detail below with reference to drawings.  FIG. 1  is a schematic planar view for illustrating a container manufacturing method according to an embodiment of this disclosure, and  FIG. 2  is a diagram illustrating an order of each step of the container manufacturing method according to the embodiment. 
     In  FIG. 1 , reference sign  1  indicates a preform, reference sign  2  indicates a mold for blow molding, reference sign  3  indicates a cavity and reference sign  4  indicates a container after blow molding. Further, in  FIG. 1 , a mold for blow molding  2  at a position  5  at which a liquid blow step is perform is indicated by a solid line, and the mold for blow molding  2  displaced to a slide position  6  in a mold slide step is indicated by a two-dot chain line. 
     Here, the disclosed container manufacturing method includes at least a preform feed step of feeding a bottomed tubular preform  1  formed in advance into a cavity  3  of a mold for blow molding  2 ; a liquid blow step of filling a pressurized liquid into the preform  1  disposed in the cavity  3  to perform blow molding; an ejection step of ejecting a container  4  after blow molding from the cavity  3 ; and a mold slide step of displacing the mold for blow molding  2  to a slide position  6 . Here, the “slide position” is a position that is different at least from the position  5  of the mold for blow molding  2  in the liquid blow step. In this embodiment, it is a position obtained by sliding the mold by a predetermined distance from the position  5  of the mold for blow molding  2  in the liquid blow step in the slide direction orthogonal to the transfer direction of the preform  1  in the preform feed step. It is to be noted that, in this embodiment, this slide direction is also orthogonal to the transfer direction (ejection direction) of the container  4  in the ejection step. 
     In this embodiment, as illustrated in  FIG. 2 , the container  4  is manufactured by performing each step in order of the preform feed step S 1 , the liquid blow step S 2 , the mold slide step S 3 , the cap attaching step S 4 , the mold return step S 5  and the ejection step S 6 . Further, after the ejection step S 6 , above described each step is repeated from the preform feed step S 1 , and the container  4  can be continuously manufactured. Each process of the container manufacturing method will be described below. 
     In the preform feed step S 1 , the resin preform  1  formed in advance is fed into the cavity  3  of the mold for blow molding  2  in an opened state. Here, as the preform  1  used by the container manufacturing method according to this embodiment, a preform that is formed into a bottomed tubular shape like a test tube by a resin material such as polypropylene (PP), polyethylene (PE) and polyethylene terephthalate (PET) can be used. Further, the preform  1  may be formed by laminating two or more types of resins. The preform  1  may be formed by injection molding using a mold for injection molding or by compression molding using a mold for compression molding, but it is not limited thereto, and the preform  1  formed by a variety of methods may be used. 
     The preform  1  is heated by a heating furnace or the like provided with a heater, for example, adjusted to or kept at a temperature that is suitable for liquid blow molding, in other words, a temperature at which a stretching effect is expressed, and fed to the mold for blow molding  2 . It is to be noted that, right after the preform  1  is manufactured, the heat caused by heating during injection molding still remains in the preform  1 . Thus, by using this, the preform  1  is fed to the mold for blow molding  2  right after being manufactured, and a heating process by a heating furnace or the like can be omitted. A preform transfer device can be used to transfer the preform  1  into the cavity  3 , and the preform  1  is transferred from the heating furnace into the cavity  3 , for example, through a linear path. The direction of the linear path (transfer direction) is the same as the longitudinal direction of the mold  2 , in other words, the alignment direction of a plurality of cavities  3  disposed in series. The preform transfer device may be configured, for example, such that it includes a plurality of grippers (in this example, six, which is the same as the number of the cavity  3 ) capable of gripping a mouth of the preform  1 . In this case, the preform transfer device transfers each preform  1  to its corresponding cavity  3  by gripping, for example, a mouth (neck ring, etc.) of each of six preforms  1  disposed in series by each gripper. It is to be noted that, in the preform feed step S 1 , the mold for blow molding  2  may be displaced to the position close to the heating furnace or to an injection molding device of the preform  1 . In this case, after the preform  1  is placed in the cavity  3 , the mold for blow molding  2  is displaced to the position  5  at which the liquid blow step S 2  is performed, and the liquid blow step S 2  is performed. 
     In the liquid blow step S 2 , a pressurized liquid is fed to each preform  1  fed into each cavity  3  and liquid blow molding is performed. Here, the mold for blow molding  2  is a batch-type mold including six cavities  3  disposed linearly in series as illustrated in  FIG. 1 , for example. The mold for blow molding  2  can be opened right and left (in the horizontal direction), and by opening the mold for blow molding  2 , each cavity  3  is released at a time and each container  4  after blow molding can be ejected from the mold for blow molding  2 . Further, preforms  1  are inserted into cavities  3  respectively with each mold for blow molding  2  opened, and subsequently each mold for blow molding  2  is clamped. Thus each preform  1  can be placed in each cavity  3 . The upper surface of the mold for blow molding  2  is opened upward, and the mouth of the preform  1  is disposed in the opening. 
     A nozzle unit is provided on top of the mold for blow molding  2 , and the nozzle unit is connected to a pressurized liquid feed machine. The pressurized liquid feed machine can feed, through the nozzle unit, a liquid pressurized to a pressure suitable for liquid blow molding to a plurality of preforms  1  disposed in each cavity  3  of the mold for blow molding  2 . The pressurized liquid feed machine may be configured such that it includes a plunger pump actuated by a servo motor, for example. 
     The nozzle unit is vertically movable and can come in contact with the upper surface of the mold for blow molding  2 . Further, the nozzle unit includes a plurality (six in this embodiment) of nozzles (not illustrated). The nozzles are fitted into the mouth of the preform  1  placed in each cavity  3  of the mold  2  when they come in contact with the upper surface of the mold for blow molding  2 . Then a pressurized liquid fed from the pressurized liquid feed machine can be fed into the preform  1  through the nozzles. 
     It is to be noted that the nozzle unit may be configured such that it includes a stretching rod configured to axially stretch the preform  1  when liquid blow molding is performed. Further, the pressurized liquid feed machine may be configured such that it includes a liquid temperature adjusting device that circulates a liquid in the nozzle unit while maintaining the temperature of the liquid constant. 
     As a liquid for liquid blow molding fed into the preform  1  by the pressurized liquid feed machine, content liquids such as beverages, cosmetics and chemicals filled finally in bottles as end-products may be used, and as a result of this, a process of filling content liquid into a container after molding may be omitted. Thus the manufacturing process of the container and the structure of the container manufacturing device can be simplified. 
     In the mold slide step S 3 , the mold for blow molding  2  is slid to the above described slide position  6 . In this embodiment, the mold for blow molding  2  is slid along with the container  4  that is blow molded in the liquid blow step S 2 . It is to be noted that, as a configuration of sliding the mold for blow molding  2 , for example, a guide rail is provided on the bottom, the top or the side of the mold for blow molding  2 , and along the rail the mold for blow molding  2  is displaced. The slide direction is a horizontal direction that is orthogonal to the transfer direction of the preform  1 . The slide position  6  can be a position that is not overlapped with the nozzle unit and the preform transfer device. As a result of this, equipment such as a nozzle unit and a preform transfer device does not block the up and down direction of the mold for blow molding  2  at the slide position  6 , which allows for easy attachment of a cap to the mouth from the top of the container  4 . 
     In the cap attaching step S 4 , a cap is attached to the mouth of the container  4 . In this embodiment, the cap attaching step S 4  is performed at the slide position  6 . Thus there is no nozzle unit or the like on top of the mold for blow molding  2 , and therefore a cap can be easily attached. Further, a device for attaching a cap can be easily disposed. It is to be noted that, when the cap and the mouth are connected by screw, for example, the cap attaching step S 4  is performed by turning the cap, and when the cap and the mouth are engaged in an undercut manner, the cap attaching step S 4  is performed by capping or the like. Preferably, a cap is attached with the container  4  held in a mold. 
     In the mold return step S 5 , the mold for blow molding  2  is returned to the position  5  at which the liquid blow step S 2  is performed. In the mold return step S 5 , the mold is slid in the direction opposite to that of the mold slide step S 3 , and a guide rail or the like may be used as with the mold slide step S 3 . 
     In the ejection step S 6 , the container  4  is ejected from the mold for blow molding  2 . In this embodiment, the container  4  with a cap attached thereto is ejected. The container  4  disposed in the cavity  3  is transferred, along a linear path, by a transfer device provided separately from the preform transfer device. In this embodiment, the transfer direction of the container  4  is in parallel with (in line with) the transfer direction of the preform  1  in the preform feed step S 1 , and is orthogonal to the slide direction in the above described mold slide step S 3 . 
     It is to be noted that, the ejection step S 6  may be configured such that, before the mold return step S 5 , the mold for blow molding  2  is opened at the slide position  6  to eject the container  4  from the cavity  3 . In this case, the mold return step S 5  is performed after the container  4  is ejected from the cavity  3 . 
     As described above, in the container manufacturing method according to this embodiment, the mold for blow molding  2  is slid to the slide position  6  that is different from the position  5  of the mold in the preform feed step S 1  and the liquid blow step S 2 , and thus the cap attaching step S 4  can be easily performed at a position where the mold is not overlapped with the nozzle unit or the like. Thus, the cap attaching step S 4  can be performed before the ejection step S 6  of ejecting the container  4  from the cavity  3  of the mold for blow molding  2 , which allows for preventing the content liquid from spilling out of the container  4  in the ejection step S 6 . 
     It is to be noted that, in this embodiment, a decoration step S 7  may be added. In the decoration step S 7 , a label bearing characters and designs, for example, is inserted from top, bottom or side of the opened mold for blow molding  2 . In other words, after a label is inserted into the mold for blow molding  2  at the slide position  6 , the mold for blow molding  2  is displaced to the position  5  at which the liquid blow step S 2  is performed (mold return step S 5 ), and thus a label can be adhered to the outer surface of the container  4  after blow molding through the preform feed step S 1  and the liquid blow step S 2 . As a result of this, a process of adhering a label to the outer surface of a container after the container is ejected from the mold for blow molding  2  is no more necessary, and a work for decoration can be simplified. It is to be noted that, in this case, preferably, after the cap attaching step S 4  in  FIG. 2 , the mold is opened at the slide position  6  and the ejection step S 6  is performed. Further, as the decoration step S 7 , a label is inserted into the cavity  3  of the mold  2  from which the container  4  is ejected, after that the mold return step S 5  is performed, and each step is repeated again from the preform feed step S 1 . When the method is configured in the above described manner, it is no longer necessary to perform the mold slide step S 3  and the mold return step S 5  twice for each in one manufacturing cycle, and thus the manufacturing efficiency can be increased. It is to be noted that, as the decoration step S 7 , for example, printing and transfer capable of being performed in the mold  2  can be performed. 
     Another embodiment of this disclosure will be described below. In the above described embodiment, the mold slide step S 3  is performed after the preform feed step S 1  and the liquid blow step S 2 , and the cap attaching step S 4  is performed. However, in this embodiment, the mold slide step S 3  is provided before the preform feed step S 1 , and a label is disposed in advance in the cavity  3  of the mold for blow molding  2 , and a cap is attached after the ejection step S 6 . In other words, as illustrated in  FIG. 3 , first, the mold slide step S 3  is performed, and after that, as the decoration step S 7 , a label is disposed in the cavity  3  of the mold for blow molding  2  located at the slide position  6 . After that, the mold return step S 5  is performed to return the mold for blow molding  2  to its original position (the position  5  at which the liquid blow step S 2  is performed). Then, in the preform feed step S 1 , the preform  1  is fed to the inside of the label disposed in advance in the cavity  3  and is clamped. After that the liquid blow step S 2  is performed. In this case, when the preform  1  is expanded and deformed in the liquid blow step S 2 , the label is disposed in close adherence to the outer periphery thereof. After the liquid blow step S 2 , the container  4  is ejected in the ejection step S 6 , and after that a cap is attached. 
     It is to be noted that, the mold slide step S 3  is performed again after the liquid blow step S 2  and before the ejection step S 6  such that the ejection step S 6  is performed with the mold for blow molding  2  disposed at the slide position  6 . 
       FIG. 4  illustrates still another embodiment, in which the decoration step and the cap attaching step or the like are performed after the ejection step S 6 . In this embodiment, the mold slide step S 3  is performed after the preform feed step S 1  and the liquid blow step S 2 , the ejection step S 6  is performed at the slide position  6 , and after that the mold return step S 5  is performed. In this manner, when the ejection step S 6  is performed at the slide position  6  where a nozzle unit or the like is not overlapped thereon, a gripper of a transfer device of the container  4  can be easily inserted from the top of the mold for blow molding  2 . In other words, in the ejection step S 6 , limitation of the ejecting direction and the ejecting method of the container  4  by the nozzle unit or the like can be prevented. It is to be noted that, when the decoration step is performed after the container  4  is ejected from the mold for blow molding  2  as with this embodiment, in addition to the decoration method using a shrink label and a roller label never before possible in a mold, a decoration method such as a printing never before possible will be possible. 
       FIG. 5  is a schematic planar view for illustrating a container manufacturing method according to yet another embodiment of this disclosure, and  FIG. 6  is a diagram illustrating an order of each step of the container manufacturing method. In this embodiment, as illustrated in  FIG. 5 , two molds for blow molding  2   a  and  2   b  configured to be slidable to the slide positions  6   a  and  6   b  different from each other are alternately used to perform the liquid blow step S 2 . The position  5  at which the liquid blow step S 2  is performed is located on a transfer path of the preform  1 , for example, and the two molds for blow molding  2   a  and  2   b  are configured to be slidable to the slide positions  6   a  and  6   b , respectively, such that the position  5  at which the liquid blow step S 2  is performed is located between them. 
     As illustrated in  FIG. 5  with a solid line, while one mold for blow molding  2   a  of the two molds for blow molding  2   a  and  2   b  is located at the first slide position  6   a , the preform feed step S 1  and the liquid blow step S 2  are performed by using the other mold for blow molding  2   b  located at the position  5 . Further, as illustrated in  FIG. 5  with a two-dot chain line, while the other mold for blow molding  2   b  is located at the second slide position  6   b , the preform feed step S 1  and the liquid blow step S 2  are performed by using the one mold for blow molding  2   a  located at the position  5 . It is to be noted that, as illustrated in  FIG. 6 , each of the molds for blow molding  2   a  and  2   b  can continuously manufacture the container  4  by repeating in order of the preform feed step S 1 , the liquid blow step S 2 , the mold slide step S 3  (S 3 ′), the ejection step S 6  (S 6 ′) and the mold return step S 5  (S 5 ′). 
     In this embodiment, the preform feed step S 1  is performed at the position  5  at which the liquid blow step S 2  is performed, and the ejection step S 6  (S 6 ′) of the container  4  is performed at respective slide positions  6   a  and  6   b . It is to be noted that, the above described decoration step S 7  and cap attaching step S 4  may be performed at respective slide positions  6   a  and  6   b . Further, the preform feed step S 1  and the ejection step S 6  (S 6 ′) may be performed at respective slide positions  6   a  and  6   b , or the preform feed step S 1  may be performed at respective slide positions  6   a  and  6   b , and the ejection step S 6  (S 6 ′) may be performed at the position  5  at which the liquid blow step S 2  is performed. 
     As described above, in this embodiment, the liquid blow step S 2  is performed by alternately using the two molds for blow molding  2   a  and  2   b , which allows, while one mold for blow molding  2   a  of the two performs the ejection step S 6  or the like at the slide position  6   a , the liquid blow step S 2  can be performed by using the other mold for blow molding  2   b . Thus the manufacturing efficiency of the container  4  can be increased. 
     Further, in this embodiment, one transfer device is used for the preform  1 . Thus, compared with the case where a transfer device of the preform  1  is provided for each of the two molds for blow molding  2   a  and  2   b , the overall manufacturing device cost can be reduced. 
     Further, in this embodiment, in terms of further increasing the manufacturing efficiency of the container  4 , as illustrated in  FIG. 6 , preferably, the mold slide step S 3  of one mold for blow molding  2   a  and the mold return step S 5 ′ of the other mold for blow molding  2   b  are performed simultaneously. 
     In the same manner, preferably, the mold return step S 5  of one mold for blow molding  2   a  and the mold slide step S 3 ′ of the other mold for blow molding  2   b  are performed simultaneously. 
       FIG. 7  is a schematic planar view for illustrating a container manufacturing method according to further embodiment of this disclosure and  FIG. 8  is a diagram illustrating an order of each step of the container manufacturing method according to the embodiment. In this embodiment, the preform feed step S 1  and the ejection step S 6  are performed with the mold for blow molding  2  located at the slide position  6 . More specifically, as illustrated in  FIG. 8 , as the decoration step S 7 , a label is inserted into the cavity  3  with the mold for blow molding  2  located at the slide position  6 , and subsequently the preform feed step S 1  is performed. Then, the mold return step S 5  is performed, in which the mold for blow molding  2  is displaced from the slide position  6  to the position  5  at which the liquid blow step S 2  is performed. After the liquid blow step S 2 , the mold for blow molding  2  is slid to the slide position  6  in the mold slide step S 3 , and the cap attaching step S 4  is performed at the slide position  6 . Then the ejection step S 6  is performed at the end. It is to be noted that the decoration step S 7  is not performed, and decoration may be performed after the ejection step S 6 . 
     It is to be noted that, in the container manufacturing method illustrated in  FIG. 8 , after the liquid blow step S 2 , the ejection step S 6  may be performed at the position  5  to eject a container from the mold  2 , and a cap may be attached to the container. In this case, the mold slide step S 3  is performed after the ejection step S 6  to slide the mold for blow molding  2  from the position  5  to the slide position  6 , and each step is performed again starting from the decoration step S 7  (or the preform feed step S 1 ). 
     Needless to say, this disclosure is not limited to the above described embodiments, and may be changed in various manners without departing from the gist thereof. 
     For example, in the above described embodiments, the mold for blow molding  2  is provided with six cavities  3  disposed in series. However, the number and the arrangement of the cavity  3  may be optionally set, and the mold for blow molding  2  may have at least one cavity  3 . Further, the sliding direction of the mold for blow molding  2  is not limited to the direction orthogonal to the transfer direction of the preform  1 , and it may be optionally set such as a serial direction (linear direction) or the like. 
     REFERENCE SIGNS LIST 
     
         
         
           
               1  Preform 
               2  Mold for blow molding 
               3  Cavity 
               4  Container 
               5  Position at which a liquid blow step is performed 
               6  Sliding position 
               6   a  First sliding position 
               6   b  Second sliding position 
             S 1  Preform feed step 
             S 2  Liquid blow step 
             S 3  Mold slide step 
             S 4  Cap attaching step 
             S 5  Mold return step 
             S 6  Ejection step 
             S 7  Decoration step