JP2013132861A - Biaxial stretch blow molding apparatus, and container manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a head space in a container filled with a liquid to a predetermined amount simultaneously with the shaping of the container in a biaxial stretch blow molding apparatus for molding the container from a preform using a pressure liquid.SOLUTION: A range reaching a predetermined height position from the upper end of a stretching rod is formed as a cylindrical part having a longitudinally extending discharge passage formed therein, and a horizontal hole penetrating a cylindrical wall to communicate with a discharge passage is formed at the lower end of the cylindrical part, and the pressure liquid is supplied into the preform through the introducing passage formed between the blow nozzle and the stretching rod to shape the container. A pressure gas is supplied into the introducing passage in such a state that the supply of the pressure liquid and the liquid remaining in the part from the inside of the container to the introducing passage is pressurized to discharge a part of the liquid through the horizontal hole of the stretching rod and the discharge passage to thereby control a liquid surface to a predetermined height position.

Description

The present invention relates to a biaxial stretch blow molding apparatus for a synthetic resin preform and a method for producing a container using this apparatus.

Synthetic resin biaxially stretched blow-molded housings, especially polyethylene terephthalate (PET) resin-made biaxially stretched blow-molded housings (so-called PET bottles) exhibit a number of excellent properties. Used in many ways.
This type of container is generally formed by stretching and deforming a preform injection-molded into a bottomed cylindrical shape in the axial direction and the radial direction in a state where the preform is heated to a temperature at which a stretching effect can be exhibited. Is.

That is, as shown in FIG. 11 (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 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,
An axial direction is provided by an extending rod 116 that is inserted through an insertion hole 111 formed in the center of the blow nozzle 105 in a state in which the guide tube portion 110 that is the tip portion of the blow nozzle 105 is loosely fitted in the mouth tube portion 32 of the preform 31. In addition, the molded body 41 is stretched and formed in the radial direction by blow air as a pressurized fluid through the insertion hole 111.

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

JP 2003-251685 A JP 2000-43129 A

  Here, as described above, when a pressurized liquid is used in the biaxial stretch blow molding, the container is filled with the liquid after the container is formed, and the liquid is opened when the blow nozzle is detached from the mouth tube portion. It is difficult to control the head space of the content liquid to a certain amount by scattering from the cylindrical portion to the outside of the periphery, and the head space varies from product to product, causing problems related to merchantability.

Therefore, the present invention relates to a biaxial stretch blow molding apparatus that uses a liquid such as a beverage, cosmetics, and medicine that is finally filled in as a pressurized fluid, and a head in a container that is filled with the content liquid simultaneously with molding. It is a technical subject to control the space to a predetermined amount.

The main configuration of the biaxial stretch blow molding apparatus of the present invention for solving the above problems is as follows.
In a biaxial stretch blow molding apparatus that stretches a bottomed cylindrical preform with a mouth tube portion standing upright at its upper end in an expanded state with a pressurized liquid,
Having a blow molding mold and a blow nozzle that is in close communication with the mouthpiece in a state where the preform is mounted on the mold;
Insert a stretch rod into the blow nozzle and place it.
The extending rod has a cylindrical portion in which a discharge path extending in the vertical direction is formed in the range from the upper end portion to a predetermined height position, and communicates with the discharge passage through the cylindrical wall below the cylindrical portion. A horizontal hole is formed,
The container is shaped along the cavity of the mold by the pressurized liquid supplied into the preform through a cylindrical introduction path formed by a blow nozzle and a stretching rod,
In a state where the container is shaped and the supply of the pressurized liquid is stopped, the liquid remaining in the portion from the inside of the container to the introduction path is pressurized with the pressurized gas supplied to the introduction path, and the remaining liquid It is configured to discharge a part through the horizontal hole of the extending rod and the discharge path,
According to the height position where the horizontal hole is located, the head space in the container molded in a state filled with liquid is controlled to a predetermined amount.

According to the apparatus having the above-described configuration, in the biaxial stretch blow molding apparatus that stretches the bottomed cylindrical preform in an expanded state with a pressurized liquid,
With the bottomed cylindrical preform biaxially stretched and blown with a stretching rod and pressurized liquid, the container is shaped, and the liquid remaining in the portion from the inside of the container to the introduction path is supplied to the introduction path. By pressurizing with pressurized gas, a part of the remaining liquid can be discharged through the lateral hole and the discharge path of the stretching rod,
This liquid discharge stops spontaneously when the liquid level is lowered to the height position where the horizontal hole is located. Therefore, the liquid level of the liquid can be easily, reproducibly and reliably set at the height position where the horizontal hole is located. Can be adjusted.

  Due to the above effects, the head space in the container filled with the content liquid can be controlled to a predetermined amount simultaneously with the molding, and the liquid such as beverages, cosmetics, and medicines finally filled in the product The conventional problem in biaxial stretch blow molding that pressurizes and uses the air instead of blow air is that the liquid is scattered from the mouth tube to the outside of the periphery and it is difficult to control the liquid head space to a certain amount Can be solved.

  Another configuration of the present invention is the above main configuration, wherein a pressurized liquid supply unit that supplies pressurized liquid and a pressurized gas supply unit that supplies pressurized gas are arranged, and the pressurized liquid supply unit and the pressurized gas are arranged. The supply unit is driven by a common pressurizing device.

  According to the above configuration, it is not necessary to separately install a pressurizing device that requires a large power source such as a compressor or a pump in order to supply a pressurized gas used for discharging the liquid. Is also a permanent installation for the molding machine to supply the pressurized liquid used to expand the preform in an expanded state, so that the apparatus of the present invention can be configured without greatly changing the structure of the conventional apparatus. It becomes possible to do.

Still another configuration of the present invention is a configuration in which, in the main configuration, the discharged liquid is returned to the pressurized liquid supply unit that supplies the pressurized liquid.
Eventually, liquids such as beverages, cosmetics, and medicines filled in product containers such as casings can be recycled and used without waste.

  According to still another configuration of the present invention, in the main configuration described above, a fitting cylinder piece to be fitted into the mouth tube portion of the preform is disposed at the tip of the blow nozzle, and the diameter of the fitting cylinder piece is reduced toward the tip. A peripheral step portion is provided, and the blow nozzle is in close communication with the mouth tube portion by contacting the peripheral step portion with a seal member on the upper end surface of the mouth tube portion. .

The above configuration relates to a sealing method for closely communicating the blow nozzle to the mouth tube portion, but the above configuration can reliably maintain the sealing performance with a simple configuration, and can also be used for mounting a preform. Also, the attachment / detachment can 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.

The method for producing the container of the present invention for solving the above problems is as follows.
A method for manufacturing a synthetic resin container using the above-described biaxial stretch blow molding apparatus of the present invention, which sequentially performs the following steps (1) to (6).
(1) Blow-molding a bottomed cylindrical preform in a state where a predetermined portion excluding the mouth tube portion is heated to a temperature at which a stretching effect can be exerted and the mouth tube portion protrudes to the outside. Attach to a mold for
(2) The preform is stretched in the longitudinal direction with a stretching rod.
(3) Along with stretching in the longitudinal direction, a pressurized liquid is supplied from the mouth tube portion into the preform through the introduction path and stretched in an expanded state, and the container is stretched along the shape of the cavity of the mold. Shape.
(4) Stop the supply of pressurized liquid after the container is shaped.
(5) Supply pressurized gas to the introduction path.
(6) Pressurize the liquid remaining in the portion from the inside of the container to the introduction path with pressurized gas, and draw a part of the liquid until the liquid level reaches the height of the horizontal hole of the stretching rod. It is discharged to the outside through the side hole and the discharge path.

The biaxial stretch blow molding apparatus of the present invention has the above-described configuration.
In a state where the container is shaped by biaxially stretching and blowing a bottomed cylindrical preform with a stretching rod and pressurized liquid, the liquid remaining in the portion from the inside of the container to the introduction path is supplied to the introduction path. By pressurizing with a pressurized gas, a part of the remaining liquid can be discharged through the horizontal hole of the stretching rod and the discharge path,
This liquid discharge stops spontaneously when the liquid level is lowered to the height position where the horizontal hole is located, so the liquid level of the liquid can be easily, reproducibly and reliably adjusted to the height position where the horizontal hole is located. can do.
Due to the above-described effects, the head space in the container filled with the content liquid can be controlled to a predetermined amount simultaneously with molding.

It is a schematic explanatory drawing which shows an example of the whole structure of the apparatus of this invention. It is sectional drawing which expands and shows the principal part of the apparatus of FIG. It is a plane sectional view of the extending | stretching rod shown along the AA line in FIG. It is sectional drawing which shows the state which mounted the preform in the metal mold | die among the shaping | molding processes by the apparatus of FIG. It is sectional drawing which shows the state which made the blow nozzle communicate with the nozzle part of a preform among the shaping | molding processes by the apparatus of FIG. It is sectional drawing which shows the state which carried out the longitudinal stretch of the preform with the extending | stretching rod among the formation processes by the apparatus of FIG. It is sectional drawing which shows the state which extended | stretched preform by the pressurized liquid in the expansion | swelling state among the shaping | molding processes by the apparatus of FIG. 1, and shaped the container. It is sectional drawing which shows a mode that a part of liquid is discharged | emitted with pressurized gas among the shaping | molding processes by the apparatus of FIG. FIG. 9 is a cross-sectional view showing a state where part of the liquid has been discharged in FIG. 8. It is sectional drawing which shows the state which raised the extending | stretching rod from the state of FIG. It is sectional drawing which shows the principal part of an example of the conventional apparatus.

Embodiments of the present invention will be described below with reference to the drawings.
1-3 show an example of the embodiment of the biaxial stretch blow molding apparatus of the present invention, FIG. 1 is a schematic explanatory view showing an example of the overall configuration of the apparatus, and FIG. FIG. 3 is an enlarged cross-sectional view of the main part, and FIG. 3 is a flat cross-sectional view of the extending rod taken along line AA in FIG.
In FIG. 1, the preform 31 attached to the mold 1 is indicated by a two-dot chain line, and a box-shaped container 41 formed from the preform 31 is indicated by a solid line. In FIG. 31 is indicated by a solid line.

  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 as an accessory, a pressurizer 21, a pressurized liquid supply unit 22, a pressurized gas supply unit 23, and a second pressurized gas supply The part 24 is arranged.
As for the main part, the partition wall member 11 is disposed above the mold 1 so as to surround the outer peripheral surface of the mouth tube part 32 of the preform 31 protruding above the mold 1 via the space S. ing. Further, the support flange 12 (see FIG. 2) 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 so as to maintain the mounting posture of the preform 31. Yes.

The blow nozzle 4 includes an insertion cylinder piece 5 and an introduction cylinder portion 6 that are closely connected by a seal member 7b.
The fitting cylinder piece 5 is cylindrical as a whole, has a cylindrical hollow portion inside, and is provided with a circumferential step portion 5a whose diameter is reduced toward the tip on the outer peripheral wall. Is fitted into the mouth tube portion 32 of the preform 31, and the blow nozzle 4 and the mouth tube portion 32 are tightly contacted by the contact between 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 a continuous manner.

  The introduction cylinder part 6 as a whole is a member having a cylindrical hollow part, and has a through hole 6a1 serving as a supply path Fs1 for the pressurized liquid L and an additional pressure so as to cross the peripheral wall at a predetermined height position. A through-hole 6a2 serving as the supply path Fs2 for the pressurized gas A is formed.

The stretching rod 8 is inserted and arranged coaxially in the blow nozzle 4.
The extending rod 8 has a cylindrical shape as a whole, but the range from the upper end portion to a predetermined height position is a cylindrical portion 9 in which a discharge passage Fd extending in the vertical direction is formed. At the lower end of the part 9, there are formed four horizontal holes 9a penetrating through the cylindrical wall and communicating with the discharge path Fd at four equal central angle intervals as shown in the plan sectional view of FIG. .
Of course, the size and number of the horizontal holes 9a can be appropriately determined in consideration of the viscosity of the liquid.
The blow nozzle 4 and the stretching rod 8 form a cylindrical introduction path Fi in the blow nozzle 4.

Next, looking at the attached equipment,
The pressurizing device 21 is conventionally an essential facility in blow molding, and is a large facility such as a pressurizing pump or a compressor.
From this pressurizing device 21, a pressurized gas supply unit 23 that supplies a pressurized gas A via a pipe P3 to a pressurized liquid supply part 22 that supplies a pressurized liquid L used for blow molding via the pipe P1. Further, the pressurized fluid is supplied to the second pressurized gas supply unit 24 that supplies the second pressurized gas A2 via the pipe P5.
The pressurized liquid supply unit 22, the pressurized gas supply unit 23, and the second pressurized gas supply unit 24 are in the form of a plunger pump, and the power source uses the pressurized fluid from the above-described pressurizing device 21. To do.
Of course, in consideration of the overall layout of the device, ease of control, etc., for example, a pressurizing device for the pressurized gas supply unit 23 may be separately provided.
Further, the pressurized liquid supply unit 22, the pressurized gas supply unit 23, and the second pressurized gas supply unit 24 include a cylinder with a built-in piston having two chambers in addition to the illustrated pump-like one such as a plunger. Can be used.

The pressurized liquid L supplied from the pressurized liquid supply unit 22 is supplied to the inside of the preform 31 via the pipe P2 through the supply path Fs1 of the introduction cylinder part 6 and the introduction path Fi extending in the vertical direction. Is done.
Further, the pressurized gas A supplied from the pressurized gas supply unit 23 is supplied to the introduction path Fi through the supply path Fs2 of the introduction cylinder part 6 through the pipe P4.
Here, as for the supply of the pressurized gas A, it is also possible to supply the pressurized gas A from the pressurizing device 21 directly to the introduction path Fi via the supply path Fs2 without using the pressurized gas supply section 23.
In addition, the liquid L discharged through the discharge path Fd of the stretching rod 8 is returned to the pressurized liquid supply unit 22 via the pipe P7 in a process as described later.
Of course, depending on the purpose of use, the liquid L to be discharged can be separately collected or discarded without returning to the pressurized liquid supply unit 22.

  In the apparatus shown in FIG. 1, the second pressurized gas supply unit 24 for supplying the second pressurized gas A2 is disposed. When the pressurized liquid L is supplied to the preform 31, the pressure is increased by the pressure. In the case where the diameter of the mouth tube portion 32 is deformed, the second pressurized gas is introduced into the partition wall member 11 via the pipe P6 to surround the outer peripheral surface of the mouth tube portion 32 of the preform 31. Such a diameter expansion deformation can be effectively suppressed by pressurizing the space S.

Next, the manufacturing method of the container which uses the apparatus shown in FIGS. 1-3 and biaxially stretch-blow-forms a bottomed cylindrical preform is demonstrated, referring FIGS.
For forming, the steps described in the following (1) to (7) are sequentially performed.
(1) As shown in FIG. 4, a preform 31 heated at a temperature suitable for biaxial stretch blow molding is used for blow molding in a state where the mouth tube part 32 protrudes upward. Mount on mold 1 and clamp.
(2) As shown in FIG. 5, the assembled and fixed partition wall member 11 and the blow nozzle 4 are lowered together with the extending rod 8 from above the mouth tube portion 31, and the distal end portion of the fitting tube piece 5 is fitted into the mouth tube portion 32. To do.

next,
(3) As shown in FIG. 6, the preform 31 is longitudinally stretched by the stretching rod 8.
(4) Preform through the introduction path Fi as shown in FIG. 7 through the supply path Fs1 of the introduction cylinder part 6 from the pressurized liquid supply part 22 of FIG. The pressurized liquid L is supplied into 31, the preform 31 is stretched and the container 41 is shaped along the cavity 2 of the mold 1.

next,
(5) After the container 41 is shaped as described above, the supply of the pressurized liquid L is stopped, and then from the pressurized gas supply unit 23 of FIG. 2 through the supply path Fs2 of the introduction cylinder unit 6, FIG. As shown, the pressurized gas A is supplied from above the introduction path Fi, and the pressure of the pressurized gas A pressurizes the liquid L remaining in the portion from the inside of the container 41 to the introduction path Fi, and this remains. A part of the liquid L is discharged to the outside through the horizontal hole 9a of the stretching rod 8 and the discharge path Fd.
Here, in the example shown in FIG. 8, the drawing rod 8 is lowered to the lower limit as shown in FIG. 7, and corresponds to the lower surface of the neck ring 33 of the mouth tube portion 32 shown by the one-dot chain line in FIG. 8. The height position at which the lateral hole 9a is formed in the extending rod 8 is determined so as to come to the height position.
In the apparatus shown in FIG. 1, the liquid L discharged through the discharge path Fd of the stretching rod 8 is returned to the pressurized liquid supply unit 22 via the pipe P7.
(6) If the pressurization with the pressurized gas A is continued, the discharge of the liquid L continues until the liquid level Ls of the liquid L reaches the corresponding height position where the horizontal hole 9a is located as shown in FIG. When Ls descends to this height position, the discharge of liquid stops spontaneously.
Therefore, the supply of the pressurized gas A is stopped.

next,
(7) As shown in FIG. 10, the stretching rod 8 is pulled up from the inside of the container 41, the assembled and fixed partition wall member 11 and the blow nozzle 4 are raised above the mouth tube portion 31, and the mold 1 is further molded. The container 41 filled with the liquid L is opened, and the mouth tube portion 32 is sealed with a cap (not shown) to obtain a product.
Here, as the drawing rod 8 is pulled up, the liquid level Ls is lowered to a predetermined head space Hs set in advance.

As mentioned above, although the example of embodiment of the biaxial stretch blow molding apparatus of this invention and the manufacturing method of the container using this apparatus was demonstrated, of course, this invention is not limited to the example of above-described embodiment.

As described above, the biaxial stretch blow molding apparatus using a pressurized liquid according to the present invention has a liquid headspace that is finally filled in a product such as beverages, cosmetics, and drugs simultaneously with the shaping of the container. It can be adjusted to a predetermined amount easily, with good reproducibility, and reliably, and is expected to be widely used in the field of biaxial stretch blow molding.

DESCRIPTION OF SYMBOLS 1; Metal mold | die 2; Cavity 4; Blow nozzle 5; Insertion cylinder piece 5a; Circumferential step part 6; Introduction cylinder part 6a1, 6a2; Through-hole 7a, 7b; 11; partition member 12; support rod piece 21; pressurizing device 22; pressurized liquid supply unit 23; pressurized gas supply unit 24; second pressurized gas supply unit A; (pressurized) gas A2; (Pressurization) Gas Fi; Introduction path Fs1, Fs2; Supply path Fd; Discharge path Hd; Head space L; (Pressure) Liquid Ls: Liquid levels P1 to P7; Pipe S; Space 31; Preform 32; Portion 33; neck ring 41; housing 101; mold 103; neck support collar 104; assembly recess 105; blow nozzle 110; guide tube portion 111;

Claims (5)

A biaxial stretch blow molding apparatus that stretches a bottomed cylindrical preform (31) having a mouth tube portion (32) upright at its upper end in an expanded state by a pressurized liquid, which is a mold for blow molding (1 ) And a blow nozzle (4) in close communication with the tube portion (32) in a state where the preform (31) is mounted on the mold (1), and a stretch rod is attached to the blow nozzle (4). (8) is inserted and disposed, and the extending rod (8) has a cylindrical portion (a discharge path (Fd) extending in the vertical direction inside the range from the upper end to a predetermined height position ( 9), a horizontal hole (9a) that penetrates the cylindrical wall and communicates with the discharge passage (Fd) below the cylindrical portion (9), and the blow nozzle (4) and the extending rod (8) The container (41) is shaped along the cavity of the mold (1) by the pressurized liquid (L) supplied into the preform (31) through the cylindrical introduction path (Fi) formed by The container (41) is shaped and provided with the pressurized liquid (L). In a state where the liquid (L) remaining in the portion extending from the inside of the container (41) to the introduction path (Fi) is pressurized by the pressurized gas (A) supplied to the introduction path (Fi). A part of the remaining liquid (L) is discharged through the horizontal hole (9a) and the discharge path (Fd) of the extending rod (8), and the height position where the horizontal hole (9a) is positioned. Thus, the biaxial stretch blow molding apparatus configured to control the head space (Hs) in the container (41) molded in a state filled with the liquid (L) to a predetermined amount. A pressurized liquid supply unit (22) for supplying pressurized liquid (L) and a pressurized gas supply unit (23) for supplying pressurized gas (A) are arranged, and the pressurized liquid supply unit (22) The biaxial stretch blow molding apparatus according to claim 1, wherein the pressurized gas supply section (23) is driven by a common pressurizing apparatus (21). The biaxial stretch blow molding apparatus according to claim 1 or 2, wherein the discharged liquid (L) is returned to the pressurized liquid supply section (22) for supplying the pressurized liquid (L). A fitting cylinder piece (5) to be fitted into the mouth tube portion (32) of the preform (31) is disposed at the tip of the blow nozzle (4), and the outer circumference wall of the fitting cylinder piece (5) is contracted toward the tip. A peripheral step portion (5a) having a 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 biaxial stretch blow molding device according to claim 1, 2 or 3, wherein the device is in close communication with the mouth tube portion (32). A method for producing a synthetic resin container using the biaxial stretch blow molding device according to claim 1, 2, 3 or 4, wherein the bottomed cylindrical preform (31) is formed by a mouth tube portion (32). The predetermined part except for is heated to a temperature at which a drawing effect can be exerted, and the mouth tube part (32) is attached to the blow molding die (1) in a state of protruding to the outside, and drawn. The preform (31) is stretched in the longitudinal direction by the rod (8), and the pressurized liquid (L) is introduced from the mouth tube portion (32) into the preform (31) through the introduction path (Fi). Supply and extend in an expanded state, shape the container along the shape of the cavity (2) of the mold (1), and supply the pressurized liquid (L) after the container (41) is shaped The pressurized gas (A) is supplied to the introduction path (Fi), and the liquid (L) remaining in the portion from the inside of the container (41) to the introduction path (Fi) is supplied by the pressurized gas (A). ) And the liquid level of the liquid (L) is Until it reaches the height position of the horizontal hole (9a) of the extending rod (8), it is discharged outside through the horizontal hole (9a) of the extending rod (8) and the discharge path (Fd), A method for producing a synthetic resin container.

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