JP2021133668A - Method for manufacturing liquid container - Google Patents

Abstract

To provide a method for manufacturing a liquid container, which can be efficiently manufactured without causing a defective shape of the container.SOLUTION: There is provided a method for manufacturing a liquid container, in which a nozzle unit 20 comprises: a pressurized-liquid supply source 33 that can operate in both pressurizing and suction directions; a liquid supply port that is connected to the pressurized-liquid supply source 33 and that is terminated by a blow nozzle 23; and a seal body 26 that opens and closes the liquid supply path by an advancing and retreating operation with respect to a seal surface 23b in the liquid supply port. The manufacturing method comprises: a liquid blow molding step of molding a preform 2 into a liquid container C having a shape along an inner surface of a mold 10 by supplying a liquid L pressurized by the pressurized-liquid supply source 33 from the blow nozzle 23 to inside of the preform 2; and a decompression step of reducing pressure inside the liquid container C by operating the pressurized-liquid supply source 33 in a suction direction while moving the seal body 26 forward to close the liquid supply port at the seal body 26.SELECTED DRAWING: Figure 5

Description

The present invention relates to a method for producing a liquid-containing container for producing a liquid-containing container containing a content liquid from a preform.

Synthetic resin containers such as polypropylene (PP) bottles and polyethylene terephthalate (PET) bottles contain various liquids such as beverages, cosmetics, chemicals, detergents, and toiletries such as shampoo. It is used for containment purposes. Such a container is generally manufactured by blow molding a preform formed of a synthetic resin material having the above-mentioned thermoplasticity.

As blow molding for molding a preform into a container, liquid blow molding is known in which a pressurized liquid is used instead of pressurized air as a pressure medium to be supplied to the inside of the preform.

Further, for example, as described in Patent Document 1, by using the content liquid finally contained in the container as a product as the liquid to be supplied to the preform, the container is molded and the content liquid is filled in the container. There is known a method of manufacturing a container containing a liquid containing the content liquid by simultaneously performing the above. According to such a method for manufacturing a liquid-containing container, the liquid-containing container can be manufactured at low cost by omitting the step of filling the container with the content liquid after molding.

Japanese Unexamined Patent Publication No. 2019-188996

In the conventional liquid blow molding method, the pressurized liquid supply source that supplies the pressurized liquid inside the preform can operate in both the pressurizing direction and the suction direction, and is connected to the pressurized liquid supply source. The liquid supply path ending at the blow nozzle is opened and closed by the advancing / retreating operation of the seal body with respect to the sealing surface in the liquid supply path. Further, in the above-mentioned conventional liquid blow molding method, in order to efficiently form a head space in the container after molding, the pressurized liquid supply source is operated in the suction direction with the liquid supply path opened by the sealed body. It has a depressurization step that reduces the pressure inside the container after molding.

When a seal body that moves forward and backward with respect to the seal surface in the liquid supply path is used as described above, the volume of the seal body in the liquid supply path increases or decreases due to the advance / retreat operation of the seal body, and accordingly, in the liquid supply path. The pressure also increases and decreases. As a result, particularly when molding a lightweight thin-walled or small-sized container, the shape of the container may be defective. For example, when the seal body is moved forward to bring it into close contact with the seal surface in order to form a head space after the depressurization step is performed and the liquid supply path is closed, the volume of the seal body in the liquid supply path increases. Along with this, the pressure in the liquid supply path, and eventually the pressure in the container, also increases. When the pressure inside the container is reduced in a large amount in the depressurization step in consideration of the increase in the pressure, the container may be crushed and deformed, resulting in poor shape.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a method for manufacturing a container containing a liquid, which can be efficiently manufactured without causing a shape defect of the container.

The method for manufacturing a liquid-filled container of the present invention is a method for manufacturing a liquid-filled container for manufacturing a liquid-filled container containing a content liquid from a bottomed tubular preform using a nozzle unit and a mold. The nozzle unit includes a pressurized liquid supply source that can operate in both the pressurizing direction and the suction direction, a liquid supply path that is connected to the pressurized liquid supply source and is terminated by a blow nozzle, and the inside of the liquid supply path. A seal body that opens and closes the liquid supply path by advancing and retreating with respect to the seal surface of the above, and by supplying the liquid pressurized by the pressurized liquid supply source into the inside of the preform from the blow nozzle. A liquid blow molding step of molding the preform into the liquid-containing container having a shape along the inner surface of the mold, and the pressurization while moving the seal body forward to close the liquid supply path with the seal body. It is characterized by having a depressurization step of reducing the pressure inside the liquid container by operating the liquid supply source in the suction direction.

In the method for manufacturing a liquid container of the present invention, in the above configuration, the nozzle unit has a discharge rod having a discharge port connected to a liquid suction source by a discharge path, and the liquid supply path is provided by the decompression step. A head that forms a head space in the liquid container by discharging the liquid from the inside of the liquid container by suction by the liquid suction source through the discharge port located below the blow nozzle in the closed state. It is preferable to have a space forming step.

In the method for manufacturing a container containing a liquid of the present invention, in the above configuration, the pressurized liquid supply source is operated in the pressurized direction while the seal body is retracted in order to start the liquid blow molding process. preferable.

In the above configuration, the method for manufacturing a liquid container of the present invention substantially offsets the decrease in internal pressure of the liquid supply path due to the retracting operation of the seal body for starting the liquid blow molding step. It is preferable to operate the pressure liquid supply source in the pressurizing direction.

In the method for manufacturing a container containing a liquid of the present invention, in the above configuration, air discharge to discharge the air inside the preform to the outside by supplying the liquid to the inside of the preform before the liquid blow molding step. It is preferable to have a process.

In the above configuration, the method for manufacturing a container containing a liquid of the present invention substantially offsets an increase in internal pressure of the liquid supply path due to the forward operation of the seal body for closing the liquid supply path in the decompression step. In addition, it is preferable to operate the pressurized liquid supply source in the suction direction.

According to the present invention, it is possible to provide a method for manufacturing a liquid-containing container, which can be efficiently manufactured without causing a shape defect of the container.

It is explanatory drawing which shows an example of the manufacturing apparatus of the liquid containing container used in the manufacturing method of the liquid containing container which is one Embodiment of this invention in the state of performing a standby process. It is explanatory drawing which shows the manufacturing apparatus of the container containing liquid in the state which performs the air discharge process. It is explanatory drawing which shows the manufacturing apparatus of the liquid containing container in the state which the seal body is retracted in order to start the liquid blow molding process after the air discharge process is completed. It is explanatory drawing which shows the manufacturing apparatus of the container containing a liquid in the state which a liquid blow molding process and a rod stretching process are performed. It is explanatory drawing which shows the manufacturing apparatus of the container containing a liquid in the state which a decompression process is performed. It is explanatory drawing which shows the manufacturing apparatus of the container containing liquid in the state which performs the head space formation process. It is explanatory drawing which shows the manufacturing apparatus of the container containing liquid in the state which performs the nozzle raising process. It is a flowchart which shows the manufacturing method of the container containing liquid which is one Embodiment of this invention.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

The method for manufacturing a liquid container according to an embodiment of the present invention can be carried out using, for example, the liquid container manufacturing apparatus 1 having the configuration shown in FIG.

The liquid-filled container manufacturing apparatus 1 shown in FIG. 1 manufactures a liquid-filled container C (see FIG. 7) containing the content liquid from the synthetic resin preform 2. As the liquid (content liquid) L contained in the liquid-containing container C, various liquids L such as toiletries such as beverages, cosmetics, chemicals, detergents, and shampoos can be adopted.

The preform 2 includes a cylindrical mouth portion 2a as an opening end and a cylindrical body portion connected to the mouth portion 2a by using a synthetic resin material having thermoplasticity such as polypropylene (PP) or polyethylene terephthalate (PET). A bottomed tubular shape having a 2b and a bottom portion 2c that closes the lower end of the body portion 2b can be used.

Although details are not shown, on the outer wall surface of the mouth portion 2a, an engaging protrusion for attaching a closing cap (not shown) to the mouth portion 2a of the liquid container C after molding by tapping (undercut engagement). Is provided. In addition, a male screw may be provided on the outer wall surface of the mouth portion 2a instead of the engaging protrusion, and the closing cap may be attached to the mouth portion 2a by screw connection.

The liquid container manufacturing apparatus 1 has a mold 10 for blow molding. The mold 10 has a cavity 11 having a shape corresponding to the final shape of the liquid container C such as a bottle shape. The cavity 11 opens upward on the upper surface of the mold 10. The preform 2 is mounted on the mold 10 with the body portion 2b and the bottom portion 2c arranged inside the cavity 11 of the mold 10 and the mouth portion 2a protruding upward from the mold 10.

The mold 10 can be opened to the left and right, and by molding the preform 2 into the liquid-containing container C and then opening the mold 10 to the left and right, the liquid-containing container C can be opened from the mold 10. It can be taken out.

Above the mold 10, a nozzle unit 20 for supplying the pressurized liquid L to the inside of the preform 2 is provided. The nozzle unit 20 has a main body block 21.

A support block 22 is provided at the lower end of the main body block 21, and a blow nozzle 23 is attached to the lower end of the main body block 21 supported by the support block 22. The blow nozzle 23 is formed in a substantially cylindrical shape, and the lower end portion thereof is a liquid supply port 23a. The nozzle unit main body 20a is composed of the main body block 21, the support block 22, and the blow nozzle 23. The nozzle unit main body 20a is movable relative to the mold 10 in the vertical direction. When the nozzle unit body 20a descends to the lower stroke end, the nozzle unit body 20a (more specifically, the blow nozzle 23) is attached to the mouth portion 2a of the preform 2 mounted on the mold 10 from the upper side. Engage in a sealed state.

Inside the nozzle unit main body 20a (more specifically, the main body block 21 and the blow nozzle 23), a vertical flow path 24 terminated by the liquid supply port 23a of the blow nozzle 23 is provided. The vertical flow path 24 extends in the vertical direction. In the present embodiment, the liquid supply path terminated at the liquid supply port 23a is composed of the vertical flow path 24, the liquid supply port 25 described later, the third liquid pipe PL3, and the second liquid pipe PL2. That is, the end of the liquid supply path and the end of the vertical flow path 24 are both the liquid supply port 23a.

The nozzle unit main body 20a (more specifically, the main body block 21) is provided with a liquid supply port 25 communicating with the upper end of the vertical flow path 24.

A downward conical sealing surface 23b is provided on the upper surface of the blow nozzle 23. The shape of the seal surface 23b can be changed as appropriate. The seal surface 23b may be formed by the inner peripheral surface of the blow nozzle 23, or may be formed by the upper surface and the inner peripheral surface of the blow nozzle 23. Inside the vertical flow path 24, a seal body body 26a that can be seated on the seal surface 23b is arranged. The seal body body 26a is formed in a cylindrical shape, and a downward conical tapered surface 27 is provided at the lower end of the seal body body 26a. The arrangement and shape of the tapered surface 27 can be changed as appropriate. When the seal body body 26a moves to the closed position, which is the stroke end position on the lower side, the sealed body body 26a comes into close contact with the seal surface 23b on the tapered surface 27 and closes the vertical flow path 24. On the other hand, when the seal body body 26a moves upward from the closed position, the tapered surface 27 of the seal body body 26a is separated from the seal surface 23b to open the vertical flow path 24.

As shown in FIG. 1, the seal body body 26a is fixed to the lower end of the shaft body 26b provided so as to be movable in the vertical direction relative to the nozzle unit body 20a, and is fixed in the vertical direction inside the vertical flow path 24. It is movable. The seal body body 26a is formed to have a diameter larger than that of the shaft body 26b, but is not limited to this, and may be formed to have the same diameter as the shaft body 26b, for example. Further, the seal body body 26a may be formed integrally with the shaft body 26b. The seal body 26a and the shaft body 26b form a seal body 26 that opens and closes the vertical flow path 24 by advancing and retreating with respect to the seal surface 23b.

The nozzle unit 20 has a discharge rod 28 having a discharge port 28a for the liquid L. The discharge rod 28 has an opening / closing body 28b capable of opening / closing the discharge port 28a. In the present embodiment, the discharge rod 28 has a cylindrical outer cylinder 29 having a discharge port 28a at the lower end, and an opening / closing body 28b that can move relative to the outer cylinder 29 in the vertical direction. The opening / closing body 28b has a columnar opening / closing rod 30 extending along the axial center of the outer cylinder 29 inside the outer cylinder 29 in the radial direction, and the opening / closing rod 30 has a diameter larger than that of the opening / closing rod 30 and abuts on the discharge port 28a in the vertical direction. It has a diameter-expanded portion 31 that can be detached. An in-cylinder flow path 28c is formed between the outer cylinder 29 and the opening / closing body 28b. The outer cylinder 29 may have a cylindrical shape other than a cylindrical shape (oval cylinder shape, polygonal cylinder shape, etc.). Further, the opening / closing rod 30 may have a columnar shape (elliptical columnar shape, polygonal columnar shape, etc.) other than the columnar shape. The outer cylinder 29 and the opening / closing rod 30 can be formed of, for example, a steel material. In the present embodiment, the discharge port 28a is provided at the lower end of the outer cylinder 29, but may be provided on the outer peripheral surface of the outer cylinder 29 in place of or in addition to the lower end. Further, the number and shape of the discharge ports 28a provided on the discharge rod 28 can be changed as appropriate. In the present embodiment, the discharge rod 28 is configured so that the discharge port 28a can be opened and closed, but the discharge rod 28 may be configured to have a discharge port 28a that is always open.

The discharge rod 28 is arranged inside the seal body 26 and extends along the axis of the seal body 26. The discharge rod 28 can move in the vertical direction relative to the seal body 26. The outer cylinder 29 and the opening / closing body 28b are driven individually or in cooperation with each other by a drive source (not shown).

The discharge rod 28 is used as a stretching rod that extends the preform 2 in the axial direction by moving downward. However, the discharge rod 28 may not be used as the stretching rod. Further, only the opening / closing body 28b may be used as the stretching rod.

The discharge port 28a is connected to one end of the first liquid pipe PL1 via an in-cylinder flow path 28c formed by the hollow portion of the discharge rod 28. The first liquid piping PL1 is provided with a first liquid piping valve VL1, and the first liquid piping PL1 can be opened and closed by the first liquid piping valve VL1. The first liquid piping valve VL1 is composed of a solenoid valve and is controlled to open and close by a control means (not shown). The other end of the first liquid pipe PL1 is connected to the liquid suction source 32 via the second liquid pipe PL2. As described above, in the present embodiment, the discharge port 28a is connected to the liquid suction source 32 by the discharge path composed of the in-cylinder flow path 28c, the first liquid pipe PL1 and the second liquid pipe PL2.

In the present embodiment, the liquid suction source 32 and the pressurized liquid supply source 33 described later are configured by a common pump 34 that can operate in both the pressurizing direction (forward direction) and the suction direction (reverse direction). .. The pump 34 is configured as a plunger pump including a cylinder 34a and a piston (plunger) 34b in the present embodiment, but may be another type of pump.

The other end of the first liquid pipe PL1 is also connected to the liquid supply port 25 via the third liquid pipe PL3. The third liquid pipe PL3 is provided with a third liquid pipe pressure gauge 35, and the measurement data of the third liquid pipe pressure gauge 35 is input to the control means. In this way, the pressurized liquid supply source 33 is connected to the liquid supply path composed of the vertical flow path 24 terminated by the liquid supply port 23a, the liquid supply port 25, the third liquid pipe PL3, and the second liquid pipe PL2. ing.

In the present embodiment, the liquid suction source 32 and the pressurized liquid supply source 33 are configured by a common pump 34, but the liquid suction source 32 and the pressurized liquid supply source 33 may be configured by separate pumps. good. In this case, it is preferable that the discharge path connecting the liquid suction source 32 to the discharge port 28a and the liquid supply path connecting to the pressurized liquid supply source 33 form independent paths.

The pressurized liquid supply source 33 is connected to the tank 36 via the fourth liquid pipe PL4. The tank 36 may be configured to accommodate the liquid L and to heat the liquid L to a predetermined temperature and hold the liquid L at the temperature. The fourth liquid pipe PL4 is provided with a fourth liquid pipe valve VL4, and the fourth liquid pipe PL4 can be opened and closed by the fourth liquid pipe valve VL4. The fourth liquid piping valve VL4 is composed of a solenoid valve and is controlled to open and close by the control means.

A gas supply port 23c connected to a pressurized gas supply source (not shown) is provided on the portion of the blow nozzle 23 on the downstream side of the seal surface 23b. In the present embodiment, the gas supply port 23c is provided on the inner peripheral surface of the blow nozzle 23, but the gas supply port 23c is provided on a portion other than the inner peripheral surface of the blow nozzle 23 (for example, the lower end surface of the blow nozzle 23). May be done. A gas supply path 37 is provided inside the blow nozzle 23 and the support block 22, and one end of the gas supply path 37 is terminated by a gas supply port 23c.

In the present embodiment, the gas supply path 37 has a pressurized state in which the gas pressurized from the pressurized gas supply source is supplied to the gas supply path 37 and an open state in which the gas supply path 37 is opened to the atmosphere. And the suction state in which the gas and the liquid L are sucked from the gas supply path 37 to a suction source (not shown) can be switched.

As shown in FIG. 2, the discharge rod 28 is in a state where the blow nozzle 23 is engaged with the mouth portion 2a of the preform 2 mounted on the mold 10 in a sealed state and the sealing body 26 closes the vertical flow path 24. By opening the discharge port 28a at the bottom 2c of the preform 2 and operating the pump 34 (pressurized liquid supply source 33) in the pressurizing direction (see the thick line arrow in FIG. 2), the pressurized liquid supply source 33 The liquid L can be supplied to the inside of the preform 2 via the second liquid pipe PL2, the first liquid pipe PL1, the in-cylinder flow path 28c, and the discharge port 28a (see the broken arrow in FIG. 2 and the like). At this time, the fourth liquid piping valve VL4 is closed, the first liquid piping valve VL1 is opened, and the gas supply path 37 is opened to the atmosphere. By opening the gas supply path 37 to the atmosphere, air is discharged from the inside of the preform 2 to the atmosphere through the gas supply path 37 as the liquid L is supplied to the inside of the preform 2. In addition, instead of the configuration in which the gas supply path 37 is in the open state to the atmosphere for the discharge of air, the configuration in which the gas supply path 37 is in the suction state may be used.

As shown in FIGS. 3 to 4, the blow nozzle 23 is engaged with the mouth portion 2a of the preform 2 mounted on the mold 10 in a sealed state, and the sealing body 26 seals from the state where the vertical flow path 24 is closed. By moving the body 26 backward and operating the pump 34 (pressurized liquid supply source 33) in the pressurizing direction (see the thick line arrow in FIG. 4), the second liquid pipe PL2, the third liquid pipe PL3, and the liquid supply The pressurized liquid L can be supplied to the inside of the preform 2 through the port 25 and the vertical flow path 24 (see the broken arrow in FIG. 4 and the like). At this time, the fourth liquid piping valve VL4 is closed, the first liquid piping valve VL1 is closed, the discharge port 28a is closed, and the gas supply path 37 is closed. By supplying the pressurized liquid L in this way, the preform 2 can be formed into a liquid-containing container C having a shape along the cavity 11 of the mold 10.

Further, when the seal body 26 is retracted, the volume of the seal body 26 in the vertical flow path 24 decreases with the retracting operation of the seal body 26, so that the pressure in the liquid supply path, and eventually the preform 2 When the pressure inside is lowered, the preform 2 may be crushed and deformed, which may lead to a poor shape of the liquid-containing container C formed. Such crushing deformation of the preform 2 is particularly likely to occur when the liquid L is supplied to the inside of the preform 2 in advance.

In order to prevent such a problem, in the liquid container manufacturing apparatus 1 of the present embodiment, the reduction of the internal pressure of the liquid supply path due to the retracting operation of the seal body 26 (see the white arrow in FIG. 3) is omitted. The pump 34 (pressurized liquid supply source 33) can be operated in the pressurizing direction (see the thick arrow in FIG. 3) so as to cancel each other out. That is, by operating the pump 34 (pressurized liquid supply source 33) in the pressurizing direction, the pump 34 enters the vertical flow path 24 via the second liquid pipe PL2, the third liquid pipe PL3, and the liquid supply port 25. The liquid L is supplied (see the broken arrow in FIG. 3 and the like), whereby the decrease in the volume of the seal body 26 in the vertical flow path 24 due to the retracting operation of the seal body 26 can be compensated. At this time, the liquid L may be supplied from the discharge port 28a by keeping the first liquid piping valve VL1 and the discharge port 28a open.

In the above expression of "substantially canceling the decrease in the internal pressure of the liquid supply path", the amount of decrease in the volume of the seal body 26 in the vertical flow path 24 due to the retracting operation of the seal body 26 is defined as A, and the pump When B is the amount of increase in the volume of liquid L in the liquid supply path by operating 34 in the pressurizing direction per unit time, B is within ± 5% of A (that is, 95 to 95 of A). It means that it is 105%).

In this way, the vertical flow path 24 is sufficiently opened by the sealing body 26 while substantially canceling the decrease in the internal pressure of the liquid supply path, and then the pump 34 (pressurized liquid supply source 33) is opened at a predetermined speed suitable for liquid blow molding. By operating in the pressurizing direction with, the liquid-containing container C can be molded with high accuracy.

As shown in FIG. 5, from the state where the liquid-containing container C is formed and the seal body 26 opens the vertical flow path 24, the seal body 26 moves forward in order to close the vertical flow path 24 (FIG. 5). By operating the pump 34 (pressurized liquid supply source 33) in the suction direction (see the thick line arrow in FIG. 5) while operating the pump 34 (pressurized liquid supply source 33), the liquid L inside the liquid container C is supplied. It can be discharged from the port 23a toward the pressurized liquid supply source 33 (see the broken arrow in FIG. 5 or the like), and the high pressure state inside the liquid container C and the inside of the liquid supply path can be quickly eliminated. At the time of depressurizing the inside of the liquid container C and the inside of the liquid supply path, the fourth liquid piping valve VL4 is closed and the first liquid piping valve VL1 is closed. At this time, the liquid L may be discharged from the discharge port 28a by keeping the first liquid piping valve VL1 and the discharge port 28a open. Further, the gas supply path 37 is closed until such depressurization is completed, and the invasion of the liquid L into the gas supply path 37 is suppressed.

The above depressurization is performed, for example, by promptly operating the pump 34 (pressurized liquid supply source 33) in the suction direction while the vertical flow path 24 is sufficiently opened, thereby promptly reducing the high pressure state inside the liquid-filled container C. The seal body 26 is moved forward while the pump 34 is operated in the suction direction so as to substantially cancel the increase in the internal pressure of the liquid supply path due to the forward movement of the seal body 26, and the vertical flow path 24 is closed. Can be done by

In the above expression of "substantially canceling the increase in the internal pressure of the liquid supply path", the amount of increase in the volume of the seal body 26 in the vertical flow path 24 due to the forward operation of the seal body 26 is defined as C, and the pump When D is the amount of decrease in the volume of liquid L in the liquid supply path by operating 34 in the suction direction per unit time, D is within ± 5% of C (that is, 95 to 105 of C). It means that it is%).

As shown in FIG. 6, when the blow nozzle 23 is engaged with the mouth Ca of the liquid container C in a sealed state and the sealing body 26 closes the vertical flow path 24, the discharge port 28a of the discharge rod 28 is liquid. By opening at the bottom Cc of the container C and operating the pump 34 (liquid suction source 32) in the suction direction (see the thick line arrow in FIG. 6), the liquid L inside the liquid container C is discharged from the discharge port 28a. It can be discharged toward the suction source 32 (see the broken arrow in FIG. 6 and the like). At this time, the fourth liquid piping valve VL4 is closed and the first liquid piping valve VL1 is opened. Further, the gas supply path 37 is in a pressurized state, and the pressurized gas (pressurized gas) is supplied from the gas supply port 23c to the inside of the liquid container C to discharge the liquid L through the discharge port 28a. It can be promoted or supported and the time required to form the headspace H can be shortened. Such support by the pressurized gas is particularly effective when the viscosity of the liquid L as the content liquid is high.

The operations of the nozzle unit body 20a, the seal body 26, the discharge rod 28, the pump 34 (plunger 34b), the first liquid piping valve VL1, the fourth liquid piping valve VL4, etc. are integratedly controlled by a control device (not shown above). Will be done.

Next, using the liquid-containing container manufacturing apparatus 1 having such a configuration, a liquid-containing container C in which the liquid (content liquid) L is contained inside the container having a predetermined shape from the synthetic resin preform 2 is formed. A molding method (a method for manufacturing a container containing a liquid according to the present embodiment) will be described.

As shown in FIG. 8, in the present embodiment, the standby step S1, the air discharge step S2, the liquid blow molding step S3, the depressurization step S4, the head space forming step S5, and the nozzle raising step S6 are performed in this order.

First, the standby step S1 is performed. In the standby step S1, as shown in FIG. 1, the nozzle unit 20 is located at a position upwardly separated from the mold 10, the seal body 26 closes the vertical flow path 24, and the discharge port 28a of the discharge rod 28. Is in a closed state. Further, the gas supply path 37 is in a suction state. By setting the gas supply path 37 in the suction state, it is possible to prevent the liquid L from dripping remaining in the portion of the blow nozzle 23 below the seal surface 23b.

In this standby step S1, the preform 2 which has been preheated to a predetermined temperature (for example, 80 ° C. to 150 ° C.) to the extent that stretchability is exhibited by using a heating means (not shown) such as a heater is molded. Attach to 10 and fasten the mold. At this time, since the mouth portion 2a of the preform 2 is open, the preform 2 is in a state of being filled with air.

Next, in the present embodiment, the air discharge step S2 is performed. In the air discharge step S2, as shown in FIG. 2, the nozzle unit 20 is lowered to engage the blow nozzle 23 with the mouth portion 2a of the preform 2, the gas supply path 37 is opened to the atmosphere, and the seal body 26 is formed. With the vertical flow path 24 closed and the discharge rod 28 lowered to open the discharge port 28a at the bottom 2c of the preform 2, the plunger 34b is operated in the pressurizing direction, and the preform 2 is operated from the discharge port 28a. By supplying the liquid L to the inside of the preform 2, the air inside the preform 2 is discharged to the atmosphere (outside) through the gas supply path 37. That is, by supplying the liquid L to the inside of the preform 2, most of the air filled inside the preform 2 is pushed out by the liquid L to be discharged. Specifically, the discharge port 28a is opened by raising the outer cylinder 29 with respect to the opening / closing body 28b while the lower end of the opening / closing body 28b is in contact with or close to the bottom portion 2c. When the discharge of the air is completed, the discharge port 28a is closed and the gas supply path 37 is closed. Instead of discharging the air through the gas supply path 37, the air discharge path may be secured by not engaging the blow nozzle 23 with the mouth portion 2a of the preform 2. The operating speed of the plunger 34b in the air discharge step S2 is preferably set so as not to substantially stretch (expand) the preform.

As described above, in the air discharge step S2, the blow nozzle 23 is supplied with the liquid L from the discharge port 28a of the discharge rod 28 instead of opening the vertical flow path 24 in the seal body 26 to supply the liquid L. It is possible to suppress the intrusion of the liquid L into the gas supply port 23c provided on the inner peripheral surface, and to smoothly discharge the air from the inside of the preform 2 through the gas supply path 37. Further, in the air discharge step S2, by supplying the liquid L with the discharge port 28a positioned at the bottom 2c of the preform 2, the discharge port 28a is immediately immersed in the liquid after the supply of the liquid L and is immersed in the liquid. Since the liquid L can be supplied from the liquid L, it is possible to effectively suppress the entrainment of air that causes foaming and the like in the liquid L filled inside the preform 2. By suppressing the entrainment, air is suppressed from being mixed into the liquid L inside the liquid container C formed by the liquid blow molding step S3, so that the headspace H having a desired size is stabilized in the headspace forming step S5. Can be formed. Further, by suppressing the entrainment, the amount of air bubbles contained in the liquid L returned to the inside of the nozzle unit 20 in the head space forming step S5 is reduced, so that the mixing of air into the liquid supply path is also suppressed and the molding conditions are stabilized. It is possible to improve the properties and moldability of the container.

However, the air discharge step S2 is performed by opening the vertical flow path 24 with the seal body 26 and supplying the liquid L instead of supplying the liquid L from the discharge port 28a of the discharge rod 28 in this way. May be good. Further, the air discharge step S2 may not be performed.

When the air discharge step S2 is completed, the liquid blow molding step S3 is then performed. In the liquid blow molding step S3, first, as shown in FIG. 3, the vertical flow path 24 is moved backward by moving the seal body 26 backward while the blow nozzle 23 is engaged with the mouth portion 2a of the preform 2. open. At this time, the pump 34 (pressurized liquid supply source 33) is operated in the pressurizing direction so as to substantially cancel the decrease in the internal pressure of the liquid supply path due to the retracting operation of the seal body 26. As a result, it is possible to prevent the preform 2 from being crushed and deformed, and to prevent the shape of the container from being defective. The operating speed of the pump 34 at this time is smaller than the operating speed of the pump 34 in the liquid blow molding step S3.

Further, in the liquid blow molding step S3, after opening the vertical flow path 24, as shown in FIG. 4, the liquid L pressurized by the pressurized liquid supply source 33 from the liquid supply port 23a into the inside of the preform 2 is applied. Supply, thereby molding the preform 2 into a liquid container C shaped along the cavity 11 of the mold 10. In the present embodiment, the discharge port 28a is closed in the liquid blow molding step S3, but the liquid L can be filled from the discharge port 28a in the open state. After molding the liquid-containing container C in this way, the depressurization step S4 described later is performed.

In the present embodiment, as shown in FIG. 4, the rod stretching step is performed during the liquid blow molding step S3 or before the liquid blow molding step S3. In the rod stretching step, the body portion 2b of the preform 2 is stretched in the axial direction (longitudinal direction) by the discharge rod 28 (stretching rod) that advances and moves downward. In the present embodiment, the discharge rod 28 descends with the discharge port 28a closed. By performing the liquid blow molding step S3 after or during the rod stretching step (the rod stretching step may be started after the start of the liquid blow molding step S3), the preform 2 is stretched axially by the stretching rod. Since biaxial blow molding can be performed while performing blow molding, the preform 2 can be more accurately molded into a liquid-containing container C having a predetermined shape. However, the liquid blow molding step S3 may be performed without performing the rod stretching step. FIG. 1 shows a state in which the discharge rod 28 is in the original position. The lower end of the discharge rod 28 does not have to be located at the height shown in FIG. 1 in the original position, and may be located above or below the height.

Since the liquid blow molding step S3 is performed in the air discharge step S2 in a state where most of the air inside the preform 2 is discharged to the outside, when the pressurized liquid L is supplied to the inside of the preform 2. The liquid L does not entrain air, which suppresses the mixing of air into the liquid L inside the liquid container C.

When the liquid blow molding step S3 is completed, the depressurization step S4 is then performed. As shown in FIG. 5, in the present embodiment, in the depressurization step S4, the seal body 26 advances the seal body 26 in order to close the vertical flow path 24 from the state where the seal body 26 opens the vertical flow path 24. While operating, the pump 34 (pressurized liquid supply source 33) is operated in the suction direction to reduce the pressure inside the liquid container C.

In such a depressurization step S4, for example, first, the pump 34 is operated in the suction direction while the vertical flow path 24 is open in the seal body 26, thereby eliminating the high pressure state inside the liquid container C. Next, the seal body 26 is moved forward to close the vertical flow path 24 while the pump 34 is operated in the suction direction so as to substantially cancel the increase in the internal pressure of the liquid supply path due to the forward movement of the seal body 26. By doing so, it can be done. As described above, in the depressurization step S4, the pump 34 (pressurized liquid supply source 33) is operated so as to substantially offset the increase in the internal pressure of the liquid supply path due to the forward operation of the seal body 26 for closing the liquid supply path. This can be done by operating in the suction direction. The pump 34 may be operated in the suction direction so as to gradually eliminate the high pressure state inside the liquid container C as the seal body 26 for closing the vertical flow path 24 moves forward. ..

In the present embodiment, the depressurization step S4 is performed so that the high pressure state inside the liquid container C is eliminated. However, the depressurization step S4 may be performed so that at least the pressure inside the liquid container C at the time of container molding (that is, at the completion of the liquid blow molding step S3) is reduced. In the depressurization step S4, the gas supply path 37 is maintained in a closed state.

By reducing the pressure inside the liquid-filled container C by this depressurization step S4, the total amount of the liquid L to be discharged from the inside of the liquid-filled container C in the subsequent head space forming step S5 is reduced, and the head space H The formation efficiency can be increased. Further, in the head space forming step S5, the pressurized gas can be smoothly introduced into the liquid-filled container C, and the formation efficiency of the head space H can be improved in this respect as well.

For example, the pressure inside the liquid container C at the completion of the liquid blow molding step S3 can be +3 MPa (gauge pressure). Further, in such a high pressure state, the detection value of the third liquid pipe pressure gauge 35 provided in the liquid supply path by the depressurization step S4 is −0.5 MPa to +0.5 MPa (more preferably −0.1 MPa). It can be solved by lowering the pressure inside the liquid container C until it becomes ~ + 0.1 MPa).

When the depressurization step S4 is completed, the head space forming step S5 is then performed. As shown in FIG. 6, in the present embodiment, in the head space forming step S5, the discharge port 28a of the discharge rod 28 and the first liquid piping valve VL1 are opened, and the pump 34 (pressurized liquid supply source 33) is sucked in the suction direction. A head space H having a desired size is formed inside the liquid container C by the suckback that discharges the liquid L from the inside of the liquid container C through the discharge port 28a. In this embodiment, this suckback is performed in a state where the discharge port 28a is located at the bottom Cc of the liquid container C. As a result, it is possible to suppress the mixing of air into the discharge path, and thus the mixing of air into the liquid supply path. However, the liquid L may be sucked out from the discharge port 28a with the discharge port 28a positioned above the bottom Cc of the liquid container C. Even in this case, by sucking the liquid L from the liquid through the discharge port 28a located below the liquid supply port 23a, the mixing of air into the liquid supply path is suppressed as compared with the case where the liquid L is sucked out through the liquid supply port 23a. can do.

Further, in the present embodiment, in order to shorten the time required for sucking back through the discharge port 28a due to the operation of the pump 34 in the suction direction, support is provided by the pressurized gas. That is, in the head space forming step S5, the gas supply path 37 is switched from the closed state to the pressurized state. In the present embodiment, since the high pressure state inside the liquid container C is eliminated by the depressurization step S4 described above, the gas supply path 37 is quickly switched to the pressurized state and the pressurized gas is quickly supplied. It can be introduced into the inside of the liquid container C from the mouth 23c. Therefore, the discharge of the liquid L from the discharge port 28a by the sackback can be promptly supported, and the time required for the head space forming step S5 can be effectively shortened. The operation of the pump 34 in the suction direction and the switching of the gas supply path 37 to the pressurized state may be performed first or at the same time.

In the present embodiment, when the head space forming step S5 is completed, the nozzle raising step S6 is performed. In the nozzle raising step S6, as shown in FIG. 7, the discharge port 28a and the first liquid piping valve VL1 are closed, the discharge rod 28 is raised, and the discharge rod 28 is returned to the original position. Further, the gas supply path 37 is brought into a suction state, liquid dripping from the blow nozzle 23 is suppressed, and the nozzle unit 20 is raised (see the white arrows in FIG. 7 and the like). At this time, it is preferable that the nozzle unit 20 is raised at a timing when the inside of the liquid container C is not depressurized too much. The gas supply path 37 may be brought into a suction state after the nozzle unit 20 is raised. Next, the fourth liquid piping valve VL4 is opened, and the plunger 34b of the pump 34 (pressurized liquid supply source 33) is operated in the suction direction (see the thick arrow in FIG. 7) to fill the pressurized liquid supply source 33. (See the dashed arrow in FIG. 7). Then, the container C containing the liquid is taken out from the mold 10 and the process proceeds to the standby step S1 shown in FIG.

It goes without saying that the present invention is not limited to the above-described embodiment and can be variously modified without departing from the gist thereof.

For example, the nozzle unit 20 used in the method for manufacturing a liquid-containing container according to the above embodiment is connected to a pressurized liquid supply source 33 that can operate in both the pressurizing direction and the suction direction, and a pressurized liquid supply source 33. It may also have a liquid supply path terminated by the blow nozzle 23 and a seal body 26 that opens and closes the liquid supply path by advancing and retreating with respect to the seal surface 23b in the liquid supply path. For example, the nozzle unit 20 is not limited to the one having a discharge rod 28 having a discharge port 28a connected to the liquid suction source 32 by a discharge path.

Further, the method for manufacturing a liquid-containing container according to the above embodiment is a liquid-containing container for manufacturing a liquid-containing container containing the content liquid from a bottomed tubular preform 2 using a nozzle unit 20 and a mold 10. In the manufacturing method, the preform 2 is filled with a liquid having a shape along the inner surface of the mold 10 by supplying the liquid L pressurized by the pressurized liquid supply source 33 from the blow nozzle 23 to the inside of the preform 2. The liquid-filled container C is formed by operating the pressurized liquid supply source 33 in the suction direction while moving the seal body 26 forward in order to close the liquid supply path at the seal body 26 and the liquid blow molding step of forming the liquid into the container C. Any one may have a depressurization step of reducing the internal pressure.

For example, in the method for manufacturing a liquid container according to the above embodiment, the liquid is filled by suction by the liquid suction source 32 through the discharge port 28a located below the blow nozzle 23 in a state where the liquid supply path is closed by the depressurization step. It is not limited to the one having a head space forming step of forming a head space H in the liquid-containing container C by discharging the liquid L from the inside of the container C. Further, the method for manufacturing a container containing a liquid according to the above embodiment is not limited to one in which the pressurized liquid supply source 33 is operated in the pressurizing direction while the sealing body 26 is retracted in order to start the liquid blow molding process. .. Further, in the method for manufacturing a container containing a liquid according to the above embodiment, a pressurized liquid is supplied so as to substantially offset the decrease in the internal pressure of the liquid supply path due to the retracting operation of the seal body 26 for starting the liquid blow molding process. The source 33 is not limited to the one that operates in the pressurizing direction. Further, in the method for manufacturing a container containing a liquid according to the above-described embodiment, the liquid L is supplied to the inside of the preform 2 before the liquid blow molding step, so that the air inside the preform 2 is discharged to the outside. It is not limited to those having a process. Further, in the method for manufacturing a container containing a liquid according to the above embodiment, in the depressurization step, the increase in the internal pressure of the liquid supply path due to the forward operation of the seal body 26 for closing the liquid supply path is substantially offset. The pressure liquid supply source 33 is not limited to the one that operates in the suction direction.

1 Liquid container manufacturing equipment 2 Preform 2a Mouth 2b Body 2c Bottom 10 Mold 11 Cavity 20 Nozzle unit 20a Nozzle unit body 21 Body block 22 Support block 23 Blow nozzle 23a Liquid supply port 23b Seal surface 23c Gas supply port 24 Vertical flow path (liquid supply path)
25 Liquid supply port (liquid supply path)
26 Seal body 26a Seal body body 26b Shaft body 27 Tapered surface 28 Discharge rod 28a Discharge port 28b Opening and closing body 28c In-cylinder flow path (discharge path)
29 Outer cylinder 30 Opening / closing rod 31 Expanded diameter 32 Liquid suction source 33 Pressurized liquid supply source 34 Pump 34a Cylinder 34b Piston 35 Third liquid piping Pressure gauge 36 Tank 37 Gas supply path C Liquid container Ca Mouth Cc Bottom L Liquid (Content liquid)
PL1 1st liquid piping (excretion path)
PL2 2nd liquid piping (excretion path, liquid supply path)
PL3 3rd liquid piping (liquid supply path)
PL4 4th liquid piping VL1 1st liquid piping valve VL4 4th liquid piping valve H Headspace

Claims (6)

A method for manufacturing a liquid-containing container, which uses a nozzle unit and a mold to manufacture a liquid-containing container containing a content liquid from a bottomed tubular preform.
The nozzle unit is
A pressurized liquid source that can operate in both the pressurizing and suction directions,
A liquid supply path connected to the pressurized liquid supply source and terminated by a blow nozzle,
It has a seal body that opens and closes the liquid supply path by advancing and retreating with respect to the seal surface in the liquid supply path.
A liquid blow that forms the preform into the liquid-containing container shaped along the inner surface of the mold by supplying the liquid pressurized by the pressurized liquid supply source into the inside of the preform from the blow nozzle. Molding process and
A depressurization step of reducing the pressure inside the liquid container by operating the pressurized liquid supply source in the suction direction while moving the seal body forward to close the liquid supply path with the seal body. A method for producing a container containing a liquid, which comprises. The nozzle unit has a discharge rod having a discharge port connected to a liquid suction source by a discharge path.
With the liquid supply path closed by the decompression step, the liquid is discharged from the inside of the liquid container by suction by the liquid suction source through the discharge port located below the blow nozzle. The method for manufacturing a liquid container according to claim 1, further comprising a head space forming step of forming a head space in the liquid container. The method for producing a liquid-containing container according to claim 1 or 2, wherein the pressurized liquid supply source is operated in the pressurized direction while the seal body is retracted to start the liquid blow molding step. Claim that the pressurized liquid supply source is operated in the pressurizing direction so as to substantially offset the decrease in internal pressure of the liquid supply path due to the retracting operation of the seal body for initiating the liquid blow molding step. The method for producing a container containing a liquid according to 3. The invention according to any one of claims 1 to 4, further comprising an air discharge step of supplying a liquid to the inside of the preform prior to the liquid blow molding step to discharge the air inside the preform to the outside. The method for manufacturing a container containing a liquid according to the description. In the depressurization step, the pressurized liquid supply source is operated in the suction direction so as to substantially offset the increase in internal pressure of the liquid supply path due to the forward operation of the seal body for closing the liquid supply path. , The method for manufacturing a container containing a liquid according to any one of claims 1 to 5.

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