JP6142049B2 - Blow molding equipment - Google Patents

Description

  The present invention relates to a blow molding apparatus for a synthetic resin preform using a liquid as a pressure medium.

Blow-molded casings (so-called PET bottles) made of polyethylene terephthalate (PET) resin exhibit many excellent characteristics, and are therefore used in various fields as casing containers.
In general, this type of container is formed by expanding a preform that has been injection-molded into a bottomed cylindrical shape in an expanded state in a state where the preform is heated to a temperature at which a stretching effect can be exhibited.

That is, as shown in FIG. 8 (corresponding to FIG. 12 of Patent Document 1), the preform 31 heated to a temperature at which the stretching effect is exerted is protruded upward from the mouth tube portion 32, and the preform 31 A neck ring 33 provided integrally around the lower end of the outer peripheral surface of the mouth tube part 32 is attached to the blow mold 101 in a state of being locked to the neck support collar 103,
In a state where the guide tube portion 110 which is the lower end portion of the blow nozzle 104 is loosely fitted into the mouth tube portion 32 of the preform 31,
The stretching rod 108 inserted through the insertion hole 111 formed in the center of the blow nozzle 104 is stretched in the axial direction, and through the insertion hole 111, it is stretched in the radial direction by blow air as a pressurized fluid. Forming into the body 41 is achieved.

Patent Document 2 describes an invention relating to a method of blow-molding a preform using a liquid instead of air as a pressurizing medium.
In such a molding method, if the content liquid finally filled in the product is used as the liquid, the filling step can be omitted and the production line can be simplified.

FIG. 9A is a schematic explanatory diagram of a conventional blow molding apparatus for blow molding a preform using a liquid as a pressurized fluid.
The main part A of this apparatus has a mold 1, a blow nozzle 104, and a stretching rod 108 for longitudinally stretching the preform passing through the blow nozzle 104 and supplying a pressurized fluid adjacent to the main part A. For this purpose, a pressurized liquid supply unit 122 and a liquid circulation unit 123 are arranged as accessory equipment.

The pressurized liquid supply unit 122 is in the form of a plunger pump, which operates using a pressurized fluid Fp supplied from a pressurizing device 121 such as a pressurized pump or a compressor via a pipe P1 as a power source, and supplies pressurized liquid L. Via the pipe P2 and the electromagnetic valve V101, the blow nozzle 104 can be supplied to the inside of the preform 31 that closely fits the tip of the blow nozzle 104.
Then, the preform 31 is shaped along the cavity shape of the mold 1 by the longitudinal stretching by the stretching rod 108 and the expanding stretching by the pressurized liquid L, and the container 41 is molded.

Here, a cylindrical rod guide 104g is usually disposed at the lower end of the blow nozzle 104 in order to support the posture of the stretching rod 108 during longitudinal stretching.
FIG. 9B is a plan sectional view of the rod guide 104g. In this example, a flow path Fc is formed for making liquid flow into the preform by making petal-like cuts at eight locations in the circumferential direction. Has been.

JP 2003-251685 A JP 2000-43129 A

Here, when using a blow molding apparatus provided with a rod guide 104g as shown in FIGS. 9A and 9B and performing biaxial stretch blow molding using a liquid as a pressure medium, The rod guide 104g can support the stretching rod 108 in a stable posture without shaking the posture of the stretching rod 108 in the longitudinal stretching step of the preform 31.
However, since the rod guide 104g in which the flow path Fc is formed in a notch shape is disposed in a limited region such as the tip of the blow nozzle 104, that is, the inside of the mouth tube portion 32 of the preform 31, the flow path area However, the rate of supply of the liquid L into the preform cannot be increased, and it takes time to pressurize the preform. Therefore, there is a problem that productivity is lowered.
Furthermore, there is a problem that the stretchability of the preform, the orientation behavior of the molecules accompanying the stretching, and the crystallization behavior are adversely affected.

  Although it is possible to increase the flow path area by setting the position of the rod guide 104g above the mouth tube portion 32, the function of supporting the extending rod 108 while securing the flow path of the liquid L is possible. In order to achieve this, it is necessary to form the channel in a notch shape, and bubbles are generated when the liquid flows due to this notch structure, and the expansion deformation behavior becomes an anxiety point due to the bubbles. Or air bubbles remain in the content liquid of the final product.

Therefore, the present invention uses a liquid that finally fills the product, such as beverages, cosmetics, and medicines, as a pressurizing medium, and forms a container by longitudinal stretching using a stretching rod and expansion stretching using a pressurized liquid. In blow molding equipment,
An object of the present invention is to create a rod guide and a method for disposing it in the blow nozzle that can realize both the posture support function of the stretching rod and the fluidity of the liquid at a high level.

Among the present invention for solving the above problems, the main configuration is:
With a blow molding die and a bottomed cylindrical preform attached to the die, it has a blow nozzle that closely communicates with the mouth tube portion of the preform, and a stretching rod, and longitudinal stretching by the stretching rod And in a blow molding apparatus for shaping a container by expansion-like stretching with a pressurized liquid supplied into a preform through a blow nozzle,
A cylindrical rod-shaped shaft body is inserted and arranged so as to be movable along the axial direction of the blow nozzle,
A cylindrical rod guide is connected coaxially to the lower end of this shaft body,
The extending rod is inserted into the connected shaft body and the rod guide, and the rod guide is slidably inserted into the rod guide in a circumferential manner.
A shaft body, a rod guide, and a stretching rod constitute a seal body,
A cylindrical liquid supply path is formed on the inner peripheral surface of the blow nozzle and the outer peripheral surface of the seal body,
A seal step portion is provided at a predetermined position of the blow nozzle to reduce the diameter downward on the inner peripheral surface,
A taper edge is formed on the outer peripheral edge of the shaft body, and the valve mechanism is arranged so that the supply path can be opened and closed by contacting and uncontacting the taper edge with the seal step,
With the valve mechanism closed, the rod guide fits into the reduced diameter part directly below the blow nozzle seal step,
It is said that the rod guide is configured to be fitted / removed upward from the reduced diameter portion in the opened state of the valve mechanism.

According to the apparatus having the above configuration,
First, by adopting a configuration in which the extension rod is slidably inserted into the rod guide connected to the lower end of the shaft body, the wear resistance between the shaft body where the metal material is used and the extension rod. It is possible to suppress backlash of the orientation of the stretching rod due to gaps that need to be provided from the viewpoint of slipperiness, etc. Become.
Further, the rod guide can be formed in a short cylindrical shape, and the sliding area can be smoothly achieved by reducing the circumferential contact area with the extending rod and reducing the sliding resistance of the extending rod.

Furthermore, when the valve mechanism is closed and vertically stretched, the rod guide is fitted in the reduced diameter portion directly below the seal step, that is, the rod guide is supported by the peripheral wall of the reduced diameter portion of the blow nozzle. Can
The function of supporting the posture of the stretching rod by the reduced diameter portion is sufficiently exerted through the rod guide, and combined with the effect of suppressing the core blur of the stretching rod, the preform is stretched longitudinally by the stretching rod. Can be carried out uniformly in a state where there is no core blurring and no core misalignment.

Then, in the step of expanding the preform in an expanded state with the pressurized liquid, the valve mechanism is opened to bring the rod guide into a state of being removed from the reduced diameter portion immediately below the seal step portion, and the inside of the blow nozzle. It is formed by the peripheral surface and the outer peripheral surface of the stretching rod, and can form a liquid channel that communicates with the inside of the preform without a notch and having a sufficient channel area,
Combined with the uniform longitudinal stretchability by the rod guide described above, the container can be shaped in a stable state and with high productivity.

In addition, when using liquids that are finally filled in products such as beverages, cosmetics, and medicines as pressurized liquids, and manufacturing products that are finally filled with these liquids,
At the same time as molding, it is necessary to precisely control the head space in the container filled with the content liquid to a predetermined amount,
This head space is determined by the liquid remaining in the supply path flowing into the container as much as the extending rod is removed from the mouth tube portion at the final stage of blow molding.
In the above configuration, since the valve mechanism for stopping the supply of the liquid is disposed in the blow nozzle, this valve mechanism can also be disposed directly above the mouth tube portion of the preform. Therefore, the amount of liquid remaining in the supply path portion from the top to the upper end of the preform tube portion can be reduced and measured with high accuracy, and the head space can be controlled with higher accuracy.

  Another configuration of the present invention is that, in the main configuration described above, the rod guide is made of a polyether ether ketone (PEEK) resin.

The rod guide has the function of suppressing the core blur of the drawn rod, and the drawn rod using metal is inserted in a circumferential shape and repeatedly slides at high speed, so heat resistance, durability, wear resistance It is a member that is required to have high performance and slipperiness, and can be appropriately selected from engineering plastics or so-called super engineering plastics in consideration of food hygiene and the like depending on the application.
Among these, PEEK resin, which is one of super engineering plastics, is a material that can sufficiently exhibit these performances, and is a material suitable for a rod guide.
Other suitable materials for rod guides include engineering plastics such as polyamide resin, polyacetal resin, polybutylene terephthalate resin, super engineering plastics such as polysulfone (PSF) resin, polyimide (PI) resin, polyphenylene sulfide. (PPS) resin etc. can be mentioned.

Still another configuration of the present invention is the above main configuration,
The lower end portion of the shaft body is constructed by fitting a short cylindrical seal cylinder piece into an expanded coaxial core,
The peripheral edge of the seal cylinder piece abuts on the seal step,
The rod guide is connected to the lower end of the seal cylinder piece in a reduced diameter.

According to the above configuration, the diameter of the lower end portion of the shaft body can be largely adjusted by configuring the lower end portion of the shaft body with a short cylindrical seal cylinder piece having an enlarged coaxial core shape. The degree of freedom in designing the structure can be increased, and the sealing function can be sufficiently exhibited.
In addition, by increasing the diameter of the lower end portion of the shaft body, the diameter of the rod guide and the diameter of the reduced diameter portion can be increased correspondingly, increasing the degree of freedom in designing the liquid flow path depending on the purpose of use. It becomes possible to do.

Still another configuration of the present invention is the above main configuration,
An insertion tube piece that fits into the preform tube portion is disposed at the lower end portion of the blow nozzle, and a circumferential step portion that is reduced in diameter toward the tip is provided on the outer peripheral wall of the insertion tube piece. The blow nozzle is in close communication with the mouth tube portion by contacting the upper end surface of the mouth tube portion with a seal member.

The above configuration relates to a sealing method for tightly communicating the blow nozzle with the mouth tube portion, but the above configuration can reliably maintain the sealing performance with a simple configuration, and the mounting of the preform, Demounting can also be performed at high speed, and maintenance management including replacement of the seal member can be easily performed.
Of course, the configuration related to the sealing method is merely an example, and an appropriate sealing method can be employed in consideration of sealing performance, productivity, and the like.

  Still another configuration of the present invention is that, in the main configuration described above, the circulation of the liquid can be performed by the pressurized liquid supply unit that supplies the pressurized liquid in the closed state of the valve mechanism. is there.

In blow molding using a liquid as the pressurized fluid, the portion excluding the mouth tube portion of the preform is preheated to a temperature suitable for stretched blow molding, and the pressurized liquid is supplied into the preform and expanded. In the case of a liquid, the heat conduction with the preform is greater than that of a gas, and the temperature of the preform varies greatly depending on the temperature of the liquid. It is necessary to control the temperature of the liquid to be performed with high accuracy.
According to the above configuration, of all the blow molding processes from the process of setting the preform to the mold to the process of removing the molded container from the mold, the pressurized liquid is fed into the preform through the supply path. In other steps except the step of supplying and shaping the container, the liquid used as the pressurized fluid is circulated between the supply path and the pressurized liquid supply unit at a predetermined temperature at all times or as necessary. Can be adjusted,
The temperature of the liquid supplied into the preform for shaping the container can be controlled with high accuracy, and the shaping of the container can be achieved stably under certain temperature conditions, and the strength and heat resistance of the container It is possible to effectively solve problems such as variations in performance such as performance and inability to obtain sufficient shapeability without impairing productivity.

The blow molding apparatus of the present invention has the above-described configuration, and according to the apparatus having the main configuration of the present invention,
First, the rod guide connected to the lower end of the shaft body is inserted in a circumferential manner so that the stretching rod is slidable, so that wear resistance, slippage can be prevented between the shaft body using metal and the stretching rod. From the standpoint of properties and the like, it is possible to suppress core blurring of the stretching rod caused by a gap that needs to be provided, and the longitudinal stretching of the preform by the stretching rod can be performed smoothly.
Further, the rod guide can be formed in a short cylindrical shape, and the sliding contact of the extending rod can be achieved smoothly by reducing the area of contact with the extending rod and decreasing the sliding resistance of the extending rod.

  Furthermore, when the valve mechanism is closed and longitudinally stretched, the function of supporting the posture of the stretched rod by the reduced diameter portion is sufficiently exerted via the rod guide, and the above-described rod guide suppresses the core blurring. Combined with the effect, the longitudinal stretching of the preform by the stretching rod can be carried out uniformly in a state without core blurring and further without core misalignment.

Then, in the step of expanding the preform in an expanded state with the pressurized liquid, the valve mechanism is opened to bring the rod guide into a state of being removed from the reduced diameter portion immediately below the seal step portion, and the inside of the blow nozzle. It is formed by the peripheral surface and the outer peripheral surface of the stretching rod, and can form a liquid channel that communicates with the inside of the preform without a notch and having a sufficient channel area,
Combined with the uniform longitudinal stretchability by the rod guide described above, the container can be shaped in a stable state and with high productivity.

It is explanatory drawing which shows an example of the whole structure of the blow molding apparatus of this invention. It is sectional drawing to which the lower half part of the main part of the apparatus of FIG. 1 was expanded. It is sectional drawing which shows the state which carried out the longitudinal stretch of the preform with the extending | stretching rod from the state of FIG. 2 among the formation processes by the apparatus of FIG. FIG. 4 is a cross-sectional view showing a state immediately before completion of shaping of a container in a step of extending a preform in an expanded state by a pressurized liquid from the state of FIG. 3 in the forming step by the apparatus of FIG. 1. It is sectional drawing which shows the state which pulled up the extending | stretching rod to the predetermined | prescribed height position from the state of FIG. 4, and completed the shaping | molding of the container among the formation processes by the apparatus of FIG. FIG. 6 is a cross-sectional view showing a state in which the stretching rod is removed from the container in the state shown in FIG. 5 in the molding process by the apparatus shown in FIG. 1. It is sectional drawing which shows the other example of a formation process. It is sectional drawing which shows the principal part of an example of the blow molding apparatus by the conventional blow air. (A) is a schematic explanatory drawing which shows the conventional example of the blow molding apparatus by a pressurized liquid, (b) is a plane sectional view of a rod guide shown along CC line in (a).

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described along examples with reference to the drawings.
1 to 6 are for explaining a blow molding apparatus of the present invention and a method for producing a synthetic resin container using the apparatus. Hereinafter, the entire blow molding apparatus of the present invention will be mainly described with reference to FIGS. 1 to 6, an example of a method for manufacturing a synthetic resin container using this apparatus, that is, an example of a blow molding method using a liquid as a pressure medium will be described.

First, the overall configuration of the apparatus will be described with reference to FIGS. 1 and 2. FIG. 1 is an explanatory view showing an example of the overall configuration of the blow molding apparatus of the present invention, and FIG. FIG. 2 is an enlarged cross-sectional view of the lower half of the main part of the apparatus shown in the longitudinal section, and FIG.
FIG. 1 shows a state in which a preform 31 made of PET resin is mounted on the mold 1 and the tip of the blow nozzle 4 is fitted into the mouth tube portion 32 of the preform 31.
The shape of the preform 31 to be used is a bottomed cylindrical test tube as a whole, and a mouth tube portion 32 is erected at the upper end portion, and a neck ring 33 is disposed at the lower end portion of the mouth tube portion 32, The mouth tube portion 32 is mounted in the mold 1 in a state of protruding outward (upward in FIGS. 1 and 2).

The main part of this apparatus has a mold 1, a partition member 11, and a blow nozzle 4, and a pressurizing device 21, a pressurized liquid supply unit 22, and a liquid circulation unit 23 are arranged as accessory equipment.
As shown in FIG. 2, the partition wall member 11 is disposed above the mold 1 so as to surround the outer peripheral surface of the mouth tube portion 32 of the preform 31 protruding above the mold 1 through the space S. Has been.
The partition wall member 11 is provided with a vent hole 13 for supplying pressurized gas to the space S as required.
Further, the support rod 12 provided around the lower end of the partition wall member 11 is brought into close contact with the neck ring 33 of the preform 31 from above to maintain the mounting posture of the preform 31.

The blow nozzle 4 has a tubular shape as a whole, and is composed of an insertion tube piece 5 and a supply tube portion 6 which are closely connected by a seal member 7b.
The insertion cylinder piece 5 has a tapered cylindrical upper part and a cylindrical lower part. As shown in FIG. 2, the outer peripheral wall is provided with a circumferential step part 5a whose diameter decreases toward the lower end, and is cylindrical. Is fitted into the mouth tube portion 32 of the preform 31, and the blow nozzle 4 and the mouth tube portion 32 are brought into contact with the peripheral step portion 5a and the upper end surface of the mouth tube portion 32 via the seal member (O-ring) 7a. Are connected in close communication.

The supply cylinder portion 6 is a member having a hollow cylindrical portion as a whole, and as shown in FIG. 1, an introduction path 6a for the liquid L is disposed through the peripheral wall at the upper end portion, and the lower end portion. In the vicinity, a discharge path 6b for the liquid L is also provided penetrating the peripheral wall.
Further, a seal step 6s inclined downward in diameter is provided on the inner peripheral surface of the lower end portion of the supply tube portion 6 further below the discharge passage 6b. The seal step portion 6s is provided directly below the seal step portion 6s. Is a reduced diameter portion 6d having a smaller diameter than the portion immediately above.

Further, a seal body 9 is inserted and arranged in the axial direction (vertical direction in FIGS. 1 and 2) in the blow nozzle 4 composed of the fitting cylinder piece 5 and the supply cylinder portion 6 as described above. ing.
Here, the seal body 9 includes an elongated cylindrical rod-shaped metallic shaft body 9a configured by fitting a short cylindrical seal tube piece 9t coaxially with a lower end portion, and a lower end of the seal tube piece 9t. An elongated rod-shaped extending rod 8 is inserted into a cylindrical rod guide 9g that is connected to the cylinder axis. The lower end portion of the shaft body 9a is configured by a short cylindrical seal tube piece 9t fitted and assembled coaxially.
Here, from the viewpoint of wear resistance, slipperiness, and the like, the extending rod 8 is inserted into the shaft body 9a through a slight gap, while the extending rod 8 is slidably connected to the rod guide 9g. It is set as the structure penetrated in the shape.
The extending rod 8 is slidably inserted into the upper rod guide 6tg at the upper end portion of the supply cylinder portion 6 in a circumferential manner. (See Figure 1)
Further, the outer peripheral edge portion of the lower end surface of the seal tube piece 9t is rounded to form a tapered edge portion 9ta.

Further, the rod guide 9g is arranged so that it can be slidably inserted into and removed from the reduced diameter portion 6d.
Here, as described above, the rod guide 9g is inserted into the sliding rod in a state where the extending rod 8 is inserted in a circumferential shape and the sliding is turned back at a high speed and is in circumferential contact with the reduced diameter portion 6d. In this embodiment, the rod guide 9g is made of polyetheretherketone (PEEK) resin from the viewpoint of heat resistance, durability, wear resistance, and slipperiness.
Of course, an appropriate synthetic resin can be selected from other engineering plastics and super engineering plastics in consideration of usage conditions and the like.
The seal cylinder piece 9t and the rod guide 9g can be firmly joined in an undercut shape by injection molding of the rod guide 9g using the seal cylinder piece 9t as an insert material.

The blow nozzle 4 and the seal body 9 form a cylindrical supply path Fs communicating with the inside of the preform 31 along the axial direction of the blow nozzle 4 in the blow nozzle 4.
By moving the seal body 9 downward, the taper edge 9ta of the seal tube piece 9t is brought into contact with the seal step portion 6s provided around the inner peripheral surface of the lower end portion of the supply tube portion 6 as shown in FIGS. The connection of the supply path Fs to the inside of the preform can be brought into a closed state, and the seal body 9 can be brought into an opened state by being displaced upward as shown in FIG. The valve mechanism Vm is configured by contacting and uncontacting 9ta with the seal step 6s.
Here, the introduction path 6a described above is positioned at the upstream end of the supply path Fs, and the discharge path 6b is positioned at the downstream end of the supply path Fs and immediately upstream of the seal step 6s.

In the closed state of the valve mechanism Vm, the rod guide 9g is fitted into the reduced diameter portion 6d immediately below the seal step portion 6s of the blow nozzle 4,
In the open state of the valve mechanism Vm, the rod guide 9g is in a state of being inserted and removed upward from the reduced diameter portion 6d, and the flow path of the liquid L is opened.

Here, as described above, the stretching rod 8 and the shaft body 9a are both parts that use metal, and the stretching rod 8 and the shaft body 9a are both prevented from being worn or the relative movement between them can be achieved smoothly. Is inserted and arranged in the shaft body 9a including the seal cylinder piece 9t in a state where there is a slight gap, and there is a possibility that the stretching of the stretching rod 8 due to the gap may occur in the longitudinal stretching step.
In this regard, in the case of the above-described configuration, the extending rod 8 is slidably inserted into the rod guide 9g so that the rod guide 9g is reduced in diameter when the valve mechanism Vm is open as shown in FIG. Even in the state of being inserted and removed upward from the portion 6d, the rod guide 9g is no longer supported by the reduced diameter portion 6d, but at least due to the gap between the stretching rod 8 and the shaft body 9a including the seal cylinder piece 9t. The core blur of the rod 8 can be suppressed.

Further, when the valve mechanism Vm is closed and vertically stretched, the rod guide 9g is fitted into the reduced diameter portion 6d immediately below the seal step 6s, that is, the rod guide 9g is connected to the reduced diameter portion 6d of the blow nozzle 4. It can be in a state supported by the peripheral wall, and the function of supporting the posture of the extending rod 8 by the reduced diameter portion 6d is sufficiently exerted via the rod guide 9g.
Combined with the effect of suppressing the core blurring of the stretching rod 8 by the rod guide 9g described above, the preform is stretched vertically by the stretching rod 8 uniformly without blurring or so-called misalignment. can do.

Next, regarding the attached equipment, the pressurizing device 21 is conventionally an essential facility in blow molding, and is a large equipment such as a pressurizing pump and a compressor, and from the pressurizing device 21 via the pipe P1. The supplied pressurized fluid Fp serves as a power source for driving the plunger pump-like pressurized liquid supply unit 22 that supplies the pressurized liquid L.
The pressurized liquid supply unit 22 may be a cylinder with a built-in piston having two chambers in addition to a pump-like one such as a plunger shown in the figure.

Further, in the apparatus of the present embodiment, the liquid circulation unit 23 is disposed, and the liquid L is newly supplied from the pipe R1, adjusted to a predetermined temperature, supplied to the pressurized liquid supply unit 22 through the pipe R2, and the liquid A function is circulated between the pressurized liquid supply unit 22 and the supply path Fs in the blow nozzle 4 while adjusting L to a predetermined temperature.
That is, when the valve mechanism Vm is in the closed state as shown in FIG. 1, the liquid L is supplied from the supply path Fs → the discharge path 6b → the pipe R3 → the liquid circulation unit 23 → the pipe R2 → as necessary. The circuit is configured to circulate a circulation path CR configured as follows: pressurized liquid supply unit 22 → pipe P2 → introduction path 6a → supply path Fs.
And by providing such a circulation function, the temperature of the liquid L supplied into the preform can be controlled with high accuracy, the quality of the molded container can be stabilized, and the productivity can be increased. Become.

Next, an example of a process for blow molding a synthetic resin container using the blow molding apparatus described above will be described with reference to FIGS. (In FIGS. 1 to 6, FIGS. 2, 3, and 4 are enlarged sectional views of the lower half of the main part of the apparatus.)
In blow molding, the steps described in the following (1) to (7) are sequentially performed.
(1) First, a preform 31 in which a portion excluding the mouth tube portion 32 is heated to a temperature suitable for blow molding is attached to the mold 1 for blow molding with the mouth tube portion 32 protruding upward, Clamp the mold.
(2) Next, the partition member 11 was assembled fixed and the blow nozzle 4 is lowered from above the mouth tube portion 32, fitting fitted to Figure 1 and 2 the distal end portion of the inlet tube piece 5 to the mouth tube portion 32 State.
Here, the taper edge portion 9ta of the seal tube piece 9t constituting the lower end portion of the seal body 9 is in contact with the seal step portion 6s of the supply tube portion 6, so that the valve mechanism Vm is in a closed state and stretched. The rod 8 is inserted into the preform 31.
In this state, the rod guide 9g is fitted in the reduced diameter portion 6d immediately below the seal step portion 6s of the blow nozzle 4.
Further, the valves V1, V2, and V3 are all opened, and the liquid L circulates in the above-described circulation path CR while the temperature of the liquid L is adjusted by the liquid circulation unit 23.

(3) Next, as shown in FIG. 3 from the state of FIG. 2, the preform 31 is longitudinally stretched by the stretching rod 8, and the central portion of the bottom wall 35 of the preform 31 is connected to the lower end of the stretching rod 8 and the gold. The mold 1 is sandwiched between the bottom walls 1b.
In this longitudinal stretching process, the orientation of the stretching rod 8 is reliably supported by the upper rod guide 6tg located at the upper portion and the rod guide 9g supported by the reduced diameter portion 6d. It can be carried out uniformly without blurring and misalignment.
Here, in this embodiment, the stretching rod 8 is configured to be longitudinally stretched until the bottom wall 35 of the preform 31 comes into contact with the bottom wall 1b of the mold. However, the productivity of blow molding and the meat of the molded container In consideration of the thickness distribution and the like, it may be configured to be longitudinally stretched to an intermediate height.

(4) Next, as shown in FIG. 4, the shaft body 9a constituting the seal body 9 is displaced upward from the state of FIG. 3 to open the valve mechanism Vm, so that the rod guide 9g is reduced in diameter. by de-fitted into the flow path of the liquid L to the interior preform 31 from 6d, cylindrical formed in the outer peripheral surface of the inner peripheral surface and the stretching rod 8 of the supply cylinder portion 6 and the fitting tube piece 5 blow Bruno nozzle 4 A smooth and sufficient flow path area can be formed.
Then, the valve V3 is closed, the valve V1 is closed, and the liquid L pressurized from the pressurized liquid supply part 22 is supplied from the mouth tube part 32 via the supply path Fs in the blow nozzle 4 to the preform 31. Then, the container 41 is expanded and shaped along the shape of the cavity 2 of the mold 1.
Here, in the state of FIG. 4, the container 41 is in a state immediately before completion of shaping so that a gap can be seen between the shoulder 43 and the bottom 45 and the surface of the cavity 2. In this state, it is in loose contact with the cavity 2 surface.

Here, in the apparatus of the present embodiment, as described above, the supply flow path for the liquid L to the inside of the preform 31 can be a cylindrical flow path having a smooth and sufficient flow path area. The pressurizing time inside the preform by the liquid L can be shortened as compared with the conventional apparatus, and the production speed can be increased.
Incidentally, according to the blow molding process described above with the molding apparatus of FIG. 1, the pressurization time of the preform 31 by the pressurized liquid L is 334.23 msec, and the flow path Fc is notched as shown in FIG. It was confirmed that the pressurization time can be significantly shortened compared to 433.17 ms when the formed rod guide 104 g is disposed inside the mouth tube portion 32 of the preform 31.
In addition, since the cylindrical smooth flow path has no notches, the problems related to the generation of bubbles could be solved.

(5) Next, in a state where the supply of the pressurized liquid L is continued at a predetermined timing (the state shown in FIG. 4) before the liquid L is fully pressurized and the shaping of the container 41 is completed. As shown in FIG. 5, the stretching rod 8 is pulled up until its tip reaches a predetermined height position Htp inside the container 41.
Here, since the pressurized liquid L is filled in the container 41 by the amount that the stretching rod 8 is raised in accordance with the pulling up operation of the stretching rod 8, the volume of the container 41 is reduced as the stretching rod 8 is pulled up. While preventing the deformation, the shaping of the container 41 along the cavity 2 of the mold 1 is completed as shown in FIG. 5, and the peripheral wall of the container 41 is pressed against the surface of the cavity 2 with the pressurized liquid L. Holding pressure and cooling are possible.
In the state of FIG. 5, when the diameter of the mouth tube portion 32 is deformed by the pressure of the liquid L, pressurized gas is supplied from the vent hole 13 provided in the partition wall member 11 through the pipe P <b> 3. By introducing the inside and pressurizing the space S surrounding the outer peripheral surface of the mouth tube part 32, such a diameter expansion deformation can be effectively suppressed.

(6) Next, at a predetermined timing after the drawing rod 8 is pulled up, the shaft body 9a is displaced downward from the state of FIG. 5 as shown in FIG. 6, and the supply path Fs is closed by the valve mechanism Vm. The stretching rod 8 is removed from the container 41.
At this time, the valve L3 is opened and the liquid L is circulated again along the circulation path CR.
With the removal of the extension rod 8, all the liquid L remaining in the supply path Fs below the valve mechanism Vm flows into the container 41, and the liquid level Ls descends in the container 41. As shown, it can be adjusted to a predetermined head space Hs set in advance.

Here, in the configuration of the present embodiment, since the valve mechanism Vm for stopping the supply of the liquid L is disposed in the vicinity of the lower end portion of the blow nozzle 4, the position where the valve mechanism Vm is disposed. The amount of the liquid L remaining in the supply path Fs from the top to the upper end of the preform tube portion can be reduced and measured with high accuracy, and the head space Hs can be controlled with higher accuracy. .
On the other hand, in the conventional apparatus shown in FIG. 9, since the supply of the liquid L is stopped by the valve V101 disposed outside the blow nozzle 104, it is difficult to control the head space with high accuracy.

  (7) Although not shown, the blow nozzle 4 and the mouth tube portion 32 of the container 41 are disengaged, the mold 1 is opened, and the container 41 filled with the liquid L is taken out. The cylindrical portion 32 is sealed with a cap to obtain a product.

As mentioned above, although embodiment of the blow molding apparatus of this invention was described along the Example, as described until now, this invention is not limited to an above-described Example. Furthermore, although the apparatus of the above-described embodiment is configured to circulate the liquid L through the circulation path CR, an apparatus without this circulation circuit may be used.
Moreover, in the said Example, it was set as the structure which supplies the liquid L to the supply path Fs via the introduction path 6a from the pressurized liquid supply part 22, However, About this supply aspect, it can select suitably from various aspects. .

  Moreover, in the example of the above-described process, the timing at which the lower end of the stretching rod is pulled up from the position after the longitudinal stretching to the predetermined height position inside the container is immediately before the shaping of the container 41 shown in FIG. 4 is completed. However, during the shaping of the container by the expansion of the pressurized liquid L, at the same time as the shaping is completed, it is not particularly limited, such as after a predetermined time after the shaping is completed, the productivity Can be appropriately determined in consideration of the blow moldability including the presence or absence of volume reduction deformation, the presence or absence of residual strain in the molded container, the uniformity of the peripheral wall, and the like.

In the example of the above-described process, first, the longitudinal stretching by the stretching rod 8 is performed, and then the pressurized liquid L is supplied into the preform 31 with the valve mechanism Vm opened, as shown in FIG. The supply of the pressurized liquid L into the preform 31 can be performed together with the longitudinal stretching by the stretching rod 8.
Here, in the state of FIG. 7, the valve V3 and the valve V1 are closed from the state of FIG. 2, the shaft body 9a is raised to open the valve mechanism Vm, and the longitudinally stretched and pressurized liquid L is stretched by the stretching rod 8. The feed into the preform 31 is simultaneously performed and the longitudinal stretching is completed.

In addition, although the process shown in FIG. 7 is longitudinally stretched in a state where the rod guide 9g is detached from the reduced diameter portion 6d,
As described above, the rod guide 9g is not supported by the reduced diameter portion 6d, but at least core blurring of the extending rod 8 can be suppressed by the effect of the rod guide 9g.

  As described above, the blow molding apparatus of the present invention has a rod guide mechanism for a stretching rod that exhibits both the support function of the stretching rod and the fluidity of the liquid at a high level, and is molded. From the viewpoint of improving the quality of the container and improving the productivity, it is expected to be widely used in the field of blow molding using a liquid as a pressurized medium.

DESCRIPTION OF SYMBOLS 1; Metal mold 1b; Bottom wall 2; Cavity 4; Blow nozzle 5; Insertion cylinder piece 5a; Circumferential step part 6; Supply cylinder part 6a; Inlet path 6b; Discharge path 6s; Upper rod guides 7a, 7b; seal member 8; extension rod 9; seal body 9a; shaft body 9t; seal cylinder piece 9ta; taper edge 9g; rod guide 11; Pressurizing device 22; Pressurized liquid supply part 23; Liquid circulation part CR; Circulation path Fc; Flow path Fs; Supply path Hs; Head space L; Liquid Ls: Liquid level P1, P2, P3; Htp; height position S; space V1, V2, V3; valve Vm; valve mechanism 31; preform 32; mouth tube part 33; neck ring 35; bottom wall 41; 101; mold 103; neck Jitsuba unit 104; blow nozzle 104 g; rod guide 108; stretch rod 110; guide tube portion 111; insertion hole

Claims (5)

With the blow mold (1) and the bottomed cylindrical preform (31) attached to the mold (1), the mold (1) is in close communication with the mouth tube (32) of the preform (31). A blow nozzle (4) and a stretching rod (8), longitudinal stretching by the stretching rod (8), and pressurization supplied into the preform (31) through the blow nozzle (4). A blow molding device for shaping a container (41) by expansion in a liquid (L),
A cylindrical rod-shaped shaft body (9a) is inserted and arranged along the axial direction in the blow nozzle (4), and a cylindrical rod guide (9g) is coaxially connected to the lower end of the shaft body (9a). and, inserted the stretching rod (8) is inserted, further rod guide (9 g) in the stretching rod (8) is slidably circumferential contact shape consolidated the shaft (9a) and rod guide (9 g) The shaft body (9a), the rod guide (9g), and the extending rod (8) constitute a seal body (9), and the blow nozzle (4) has an inner peripheral surface and an outer periphery of the seal body (9). A cylindrical liquid (L) supply path (Fs) is formed on the surface, and a seal step portion (6s) is provided at a predetermined position of the blow nozzle (4). A tapered edge (9ta) is formed on the outer peripheral edge of the shaft body (9a), and the supply channel ( 9a) is brought into contact with and removed from the seal step (6s) by the taper edge (9ta). Fs) can be opened and closed with a valve mechanism (Vm) arranged, The rod guide (9g) fits into the reduced diameter part (6d) just below the seal step (6s) of the blow nozzle (4) when the valve mechanism (Vm) is open. A blow molding device in which (9g) is configured to be fitted and removed upward from the reduced diameter portion (6d). The blow molding apparatus according to claim 1, wherein the rod guide (9g) is made of polyetheretherketone resin. The lower end portion of the shaft body (9a) is configured by fitting and assembling a short cylindrical seal tube piece (9t) in a diameter-enlarged coaxial core, and the peripheral portion of the seal tube piece (9t) is a seal stepped portion. The blow molding apparatus according to claim 1 or 2, wherein a rod guide (9g) is connected to the lower end of the seal tube piece (9t) in a reduced diameter so as to abut against the seal tube piece (9t). An insertion cylinder piece (5) to be fitted into the mouth cylinder part (32) of the preform (31) is disposed at the lower end of the blow nozzle (4), and downward toward the outer peripheral wall of the insertion cylinder piece (5). A peripheral step portion (5a) to be reduced in diameter is provided around the blow nozzle (4) by contact with the peripheral step portion (5a) through the seal member (7a) on the upper end surface of the mouth tube portion (32). The blow molding device according to claim 1, 2 or 3, wherein the nozzle is in close communication with the mouth tube portion (32). The liquid (L) can be circulated by the pressurized liquid supply section (22) for supplying the pressurized liquid (L) with the supply path (Fs) when the valve mechanism (Vm) is closed. 2, 3 or 4 blow molding apparatus.

Images