JPH07100905A - Method and mold for producing hollow object - Google Patents

Abstract

PURPOSE:To certainly thrust a blow means in an expanded part to enable good molding, and perfectly perform release. CONSTITUTION:After a parison 25 is arranged between both opened molds 10, 11, mold clamping is started and the parison 25 is held between both slide molds 14,15 to precedingly perform the molding of an expanded part 7 and communication parts 5, 6 but, at this time, a blow nozzle 18 is thrust in the expanded part 7. Thereafter, mold clamping is completed and a compressed fluid is introduced into the expanded part 7 from the blow nozzle 18 to perform the blow molding of a reinforced part 4, a mouth part 3 and a body part 2 to obtain a hollow object 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a hollow body for accommodating foods, pharmaceuticals, cosmetics, industrial chemicals and the like, and a mold used for carrying out the method.

[0002]

2. Description of the Related Art Heretofore, this type of hollow body has been manufactured by the following method in order to prevent foreign matter from entering before the contents are stored.

As shown in FIG. 10, a body 102 of a hollow body 101, a mouth 103 connected to the body 102, and a mouth 10
3 and the dome-shaped head 104 and head 104 that are continuously provided
A split-type mold 108 having a cavity for forming a bag-shaped portion 105 that is continuous with a narrow portion 106,
109, the molten parison is placed between the opened molds 108 and 109, then the mold is closed, and then the blowing nozzle 107 is thrust into the bag-shaped portion 105 to remove the pressure of air. Pressurizing a pressurized fluid into the parison,
Blow molding along the cavity. After blow molding, the mold is opened to take out the hollow body 101, and then the head 10
The opening communicating with the narrow portion 106 of No. 4 is cut with a heating blade and welded and sealed at the same time to obtain a closed hollow body (see JP-A-61-63431).

Further, as shown in FIG. 11, dies 201 and 201 having a connecting portion 204 provided between adjacent cavities 203.
02, the Paris 210 is sandwiched between the molds 201 and 202, and then the Paris 210 is sucked by vacuum suction from a suction pipe 205 having an intake hole 207 projecting in the connecting portion 204 by a vacuum pump (not shown). The protruding hole 208 is attached to the tip end surface 206 of the pipe body 205 while being adsorbed.
A method of molding a hollow body in which the compressed air jetting needle 209 is inserted into the parison 210 (see Japanese Patent Publication No. 38-11831) has been proposed.

[0005]

However, among the above-mentioned conventional techniques, in the method disclosed in Japanese Patent Laid-Open No. 61-63431, the hollow body portion and the bag-shaped portion are closed at the same time. Therefore, when molding the bag-shaped portion, the parison has no degree of freedom, and the portion of the parison corresponding to the bag-shaped portion does not extend. Therefore, when the blowing nozzle is pushed into the bag-shaped portion, the parison cannot be pushed in successfully, and the parison is pressed and deformed at the tip of the blowing nozzle, so that the pressurized fluid can be introduced into the parison. It may run out. In addition, since the bag-shaped portion is a so-called total burr with burrs generated around it, the degree of close contact between the mold and the bag-shaped portion is high, and the hollow body is held on one side of the mold at the time of mold release to ensure complete mold release. Not done to. In particular, there has been an unsolved problem that it becomes difficult to release the mold because it closely adheres to the mold having the blowing nozzle.

Further, the method disclosed in Japanese Patent Publication No. 38-11831 can surely push the compressed air jetting needle into the parison, but since the contact between the connecting portion and the mold is high, the method described above is also used. As described above, there is an unsolved problem that the hollow body is held on one side of the mold during the mold release, and the mold cannot be completely released.

The present invention has been made in view of the unsolved problems of the above-mentioned conventional techniques, and the blow-in means can be surely inserted to perform good molding, and complete demolding can be performed. It is an object of the present invention to realize a method for manufacturing a hollow body and a mold used for carrying out the method.

[0008]

In order to achieve the above-mentioned object, the method for manufacturing a hollow body of the present invention comprises a body portion and a mouth portion connected to the body portion when the mold closing is completed. And a bulging portion that is continuously provided in a portion that becomes an opening portion of the mouth portion, and the opening portion of the mouth portion and the bulging portion are connected by a communication portion and a hollow body that is in communication is formed. A mold for forming a cavity is formed, and a part of the cavity for forming the bulging portion and the communicating portion can be closed in advance by using a divided-type mold, and the mold is opened. After arranging the molten parison between the molds, the mold closing of the preceding molding mold is preceded to sandwich the bulging part and the communicating part of the parison, and then the mold closing of the mold is completed. After that, a pressurized fluid may be introduced into the bulging portion. The hollow body is blow-molded through the bulging portion, the hollow body is cooled, the mold is opened leaving the preceding molding die, and the hollow body is released by the preceding molding die. It is what

Further, in the mold of the present invention, when the mold closing is completed, the body portion, the mouth portion continuously provided to the body portion, and the expansion portion continuously provided at the opening portion of the mouth portion. The protruding portion, the opening portion of the mouth portion, and the bulging portion are connected by a communicating portion, and a cavity for forming a communicated hollow body is formed, and the bulging portion of the cavity is formed. And a part for forming a communication part is a divided type mold which is a preceding mold capable of closing the mold in advance, and the preceding mold always has one end side protruding from the mating surface of the mold. A cylindrical slide die having a groove for forming the communicating portion at the tip urged by an elastic member, and the bulging portion slidably inserted in the slide die. A core type having a blowing means on the tip surface. The one in which the features.

[0010]

[Function] Prior to the mold closing of the mold, the mold closing of the pre-molding mold is preceded to clamp the bulging part and the communicating part of the parison, so that only the parison corresponding to this part is clamped. The part becomes free, the degree of freedom of the parison increases, and the blowing means can be reliably inserted into the part that will be the bulge part of the parison to perform good molding, and the mold can be opened leaving the preceding molding mold. Therefore, it is possible to release the mold at the center position of the mold opened by gripping the hollow body with the preceding mold.

[0011]

Embodiments of the present invention will be described with reference to the drawings.

First, an example of a hollow body manufactured by the method for manufacturing a hollow body of the present invention will be described.

As shown in FIGS. 1 to 4, the hollow body 1 is
A body portion 2, a mouth portion 3 continuous with the body portion 2 and having a threaded portion 3a, and a reinforcement portion 4 continuously provided to a cut portion 3b of the opening portion of the mouth portion 3. The reinforcing portion 4 is provided with a hemispherical bulging portion 7 which is located in the substantially central space and is partitioned from the reinforcing portion 4, and the reinforcing portion 4 and the bulging portion 7 are shown above and below the bulging portion 7. They are connected to each other by communicating portions 5 and 6 extending in the direction, and are also connected to each other by communicating passages 5a and 6a formed inside the communicating portions 5 and 6, respectively.

Here, the bulging portion 7 is provided for introducing a pressurized fluid such as pressurized air by inserting a blowing means such as a blowing nozzle 18 (see FIG. 5) or a blowing needle. hand,
The tip of the blowing nozzle 18 is inserted into the side wall of the bulging portion 7 to introduce the pressurized fluid into the parison 25, and the both communicating portions 5,
The pressurized fluid is introduced into the reinforcing portion 4, the mouth portion 3 and the body portion 2 one by one through the communicating passages 5a and 6a of 6 to expand the fluid. Therefore, the shape of the bulging portion 7 is not limited to a hemispherical shape, but may be any shape such as a bag shape. In any case, the blow hole 8 is left on the side wall of the bulging portion 7. . The blow hole 8 can be sealed by a sealing resin or the like in the post-processing, but if the outer surface of the side wall of the bulging portion 7 where the blow hole 8 is opened is formed in a mortar shape, the sealing resin or the like is applied. It will be easier.

In addition, the thickness of the reinforcing portion 4 in the direction perpendicular to the mating surface of the mold is the smallest on the parting line side and is tapered so as to increase toward the mouth side.

Next, an embodiment of the mold of the present invention will be described.

As shown in FIGS. 5 to 7, the mold of this embodiment is of a split type consisting of one mold 10 and the other mold 11, and when the mold closing is completed, the cylinder is closed. Part 2
A mouth 3 having a threaded portion 3a on the outer peripheral surface connected to the body 2, a reinforcing portion 4 connected to a cutting portion 3b which is an opening of the mouth 3, and a reinforcing portion. 4, a bulging portion 7 that is located in a substantially central space and is partitioned from the reinforcing portion 4, and a communicating portion 5 that extends in the vertical direction in the drawing for connecting and communicating the bulging portion 7 and the reinforcing portion 4. A cavity for molding the hollow body 1 provided with 6 is formed, and the portion of the cavity for forming the bulging portion 7 and the communicating portions 5, 6 can be closed in advance. It is composed of a pre-molding die as described above. In the present embodiment, the depth of the portion forming the reinforcing portion 4 of the cavity is tapered on the parting line side and becomes deeper toward the mouth portion 3.

One cavity surface 22 of one mold 10
One of the guide holes 2 formed perpendicularly to the mating surface 10a is formed in a portion corresponding to the bulging portion 7 and the communicating portions 5 and 6.
0 is open at one end side, and the other end side of the one guide hole 20 is one cylinder 16 installed in one die 10.
It is open to. One cylindrical slide mold 14 is slidably inserted into one guide hole 20, and a piston portion 14d integrally provided at the rear end thereof is slidably arranged in one cylinder 16. Along with
The mating surface 10a of one mold 10 is always provided by the spring 19a.
It is urged so that one end thereof protrudes more. One of the slide molds 14 has a tip end portion thereof with the communication portions 5, 6 described above.
A groove 14a for forming the is formed.

Further, as shown in FIGS. 8 and 9, an annular recess 14b is provided on the inner peripheral surface of one slide mold 14, and the annular recess 14b is connected to the vicinity of the cylinder-side end thereof. One end side of the passage 14c is opened, and the communication passage 14c
The other end side is open to a chamber 16a on the mating surface side partitioned by the piston portion 14d of one cylinder 16.
In this embodiment, the three communication passages 14c are provided at substantially equal intervals along the outer peripheral surface of the one slide die 14,
The number can be increased or decreased as needed.

Further, one core die 12 is slidably fitted into one slide die 14, and the one slide die 14 has a shape in which the front end surface forms half of the bulging portion 7. In addition, except when the one slide mold 14 is drawn into the one cylinder 16 by the completion of the mold closing of both the molds 10 and 11, the annular recess 14b is formed on the one end surface of the one core mold 12 and on the other hand. It is configured to be opened to a space surrounded by the slide mold 14.

In addition, a blowing nozzle 18 which is a blowing means for introducing a pressurized fluid is fitted into one of the core molds 12, and the tip of the blowing nozzle 18 has the one core mold 1.
2 slightly protrudes from the tip surface.

An O-ring 16b is provided between the outer peripheral surface of the piston portion 14d and the inner surface of the one cylinder 16, and an O-ring 16b is provided between the outer peripheral surface of the one slide mold 14 and the inner surface of the one chamber hole 20. 20a is provided to provide airtightness.

The other core die 13 provided on the other die 11 is different from the one core die 12 in that the tip end surface thereof has a shape that restricts the other half of the bulging portion 7 and the blowing nozzle is Not provided. But the other piston part 1
The other slide die 15 having the groove 5a and the groove 5a, the other cylinder 17 and the like are the same as the one slide die 14 and the one cylinder 16, and therefore the description thereof is omitted.

The mold of the above embodiment has the communicating portions 5, 6 having communicating passages 5a, 6a extending from the bulging portion 7 in the vertical direction in the figure.
However, instead of this, a communication part having a communication passage and a communication part having no communication passage may be molded, and a part other than the communication part having a communication passage may be formed. May be formed into a plate shape by compression. Further, the number of communicating portions provided with the communicating passages and the forming portions thereof can be arbitrarily set depending on the moldability of the resin used. In this case, the groove for forming the communication part having the communication passage provided at the tip of the core mold is provided at the tip of the core mold in correspondence with the number of communicating parts having the communication passage and the formation site.

Next, an embodiment of the method for producing a hollow body of the present invention will be described.

As shown in FIG. 5, both molds 10, 11
After the mold is opened, the melted parison 25 is extruded from the extrusion die 24 of the extruder and placed between the molds 10 and 11, and then the mold closing is started. At the time of this mold opening, one end sides of the one slide mold 14 and the other slide mold 15 are urged by springs 19a and 19b, respectively, and protrude from the mating surfaces 10a and 11a.

During the mold closing, first, the parison 25 is sandwiched between the two slide molds 14 and 15, and as the mold closing further progresses, the slide molds 14 and 15 resist the elastic force of the springs 19a and 19b, respectively. However, a negative pressure is generated at this time, and this negative pressure is generated on the tip surfaces of the slide molds 14 and 15 and the core molds 12 and 13 via the communication passages 14c. In order to act on the enclosed space, first, the bulging portion 7 and each communicating portion 5,
6 is molded.

When the mold closing is completed subsequently, as shown in FIG. 6, the slide molds 14 and 15 are further drawn into the cylinders 16 and 17, respectively, from the above-mentioned state, so that the bulging portion 7 is blown. The nozzle 18 is pushed in and the pinch-off portions 10b, 1 of both molds 10, 11 are inserted.
The parison 25 is clamped by 1b.

After the above, when the pressurized fluid is introduced into the bulging portion 7 through the blow nozzle 18, the pressurized fluid is sequentially reinforced through the communicating passages 5a and 6a of the communicating portions 5 and 6, respectively.
The hollow body 1 is blow-molded by being introduced into the mouth portion 3 and the body portion 2.

After the hollow body 1 was cooled, the mold was opened while leaving the preceding mold, and the hollow body 1 was released from the mold other than the preceding mold and opened by the preceding mold. It is held at the center of the mold.

Further, as the mold opening progresses, the holding by the preceding mold is released and the hollow body 1 is opened at the central position between the molds.

[0032]

Since the present invention is configured as described above, it has the following effects.

Prior to the mold closing of the mold, the mold closing of the pre-molding die is preceded so as to sandwich the bulging portion and the communicating portion of the parison, so that the blowing means is surely provided in the bulging portion of the parison. Since the mold can be opened by inserting it into the mold and the mold can be opened while leaving the preceding mold, the hollow body is gripped by the preceding mold and separated at the center position of the opened mold. Since it can be molded, the hollow body can be taken out easily and surely and can be automated.

Further, in addition to the above effects, the invention according to claims 4 to 5 can automatically precede the die closing of the preceding molding die by closing the die, and open the die by opening the die. Since the mold opening can be preceded by leaving the molding die, the productivity is improved.

[Brief description of drawings]

FIG. 1 is a front view showing an example of a hollow body manufactured by a method for manufacturing a hollow body of the present invention.

FIG. 2 is a partially enlarged view showing a cross section taken along the line AA of FIG. 1 and a portion in the vicinity thereof.

FIG. 3 is a partially enlarged view showing a cross section along the line CC of FIG. 2 and a portion in the vicinity thereof.

FIG. 4 is an enlarged sectional view showing a section taken along line BB of FIG.

FIG. 5 is a cross-sectional view of main parts showing one step of one embodiment of the method for producing a hollow body of the present invention, showing a state in which parison is placed in an opened mold.

6 is a cross-sectional view of a main part showing a state where the mold closing of the mold is completed and the parison is clamped after the step shown in FIG.

7 is a cross-sectional view of a main part showing a state in which a pressurized fluid is introduced into the parison and a hollow molded article is blow-molded after the step shown in FIG.

FIG. 8 is an enlarged partial cross-sectional view of one slide mold of one mold shown in FIGS. 6 to 7 and a portion in the vicinity thereof.

9 is a sectional view taken along the line DD of FIG.

FIG. 10 is a cross-sectional view of a main part of a mold showing one step of an example of a conventional method for manufacturing a hollow body.

FIG. 11 is a cross-sectional view of a main part of a mold, showing a step of another example of the conventional method for manufacturing a hollow body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hollow body 2 Body part 3 Mouth part 3a Screw part 3b Cutting part 4 Reinforcement part 5,6 Communication part 5a, 6a Communication path 7 Expansion part 8 Blow hole 10 One mold 11 The other mold 10a, 11a Matching Surfaces 10b, 11b Pinch off part 12 One core type 13 The other core type 14 One slide type 14a, 15a Groove 14b Annular recess 14c Communication passage 14d, 15d Piston part 15 The other slide type 16 One cylinder 17 The other cylinder 18 Blow nozzles 19a, 19b Spring 20 One guide hole 21 The other guide hole 22 One cavity surface 23 The other cavity surface 24 Extrusion die 25 Parison

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Claims (5)

[Claims] 1. When the mold closing is completed, the body portion, a mouth portion continuously provided to the body portion, and a bulging portion continuously provided at a portion to be an opening portion of the mouth portion are provided. The opening of the portion and the bulging portion are connected by a communicating portion, and a cavity for forming a communicated hollow body is formed, and the bulging portion and the communicating portion of the cavity are formed. Using a split type mold consisting of a pre-molding mold that allows the mold to be closed in advance, arrange the molten parison between the molds that have been opened, and then precede the mold closing of the preceding molding mold. After sandwiching the bulging part and the communicating part of the parison, and then completing the mold closing of the mold, by introducing a pressurized fluid into the bulging part, the hollow is passed through the bulging part. Blow molding the body and cool the hollow body Method for producing a hollow body, characterized in that said leaving preceding mold to open the mold the mold, to release the hollow body in the preceding mold. 2. When the molten parison is arranged between the opened molds, the mold closing of the preceding molding mold is preceded and the bulging part and the communicating part of the parison are sandwiched, and After sandwiching the bulging portion and the portion to be the communicating portion, a negative pressure is applied to the portion for forming the bulging portion of the preceding molding die so that the parison forms the bulging portion of the preceding molding die. The method for producing a hollow body according to claim 1, wherein the hollow body is adsorbed to the portion and molded. 3. Placing the projecting blowing means in the portion of the cavity for forming the bulge allows the blowing means to be thrust into the parison before the mold closing of the mold is completed. The method for producing a hollow body according to claim 1 or 2, which is characterized. 4. When the mold closing is completed, the body portion, the mouth portion continuously provided to the body portion, the bulge portion continuously provided to the opening portion of the mouth portion, and the mouth portion. The opening and the bulging portion are connected by a communicating portion, and a cavity for forming a communicated hollow body is formed, and furthermore, the bulging portion and the communicating portion of the cavity are formed. Is a divided-type mold comprising a preceding mold capable of precedingly closing the mold, and the preceding mold is constantly urged by an elastic member such that one end side thereof protrudes from the mating surface of the mold. A cylindrical slide mold having a groove for molding the communication portion at the tip, and a blowing means on the tip surface for molding the bulging portion slidably fitted in the slide mold A mold comprising a core mold. 5. A slide die, wherein a piston portion integrally provided at a rear end of the slide die is slidably arranged in a cylinder provided in the die, and an annular recess formed in an inner peripheral surface thereof. Is communicated with the chamber on the mating surface side of the cylinder by a communication passage, and the annular recess is opened to a space surrounded by the tip surface of the core mold and the slide mold. The mold according to claim 4.