JP2002254502A - Mold apparatus fro stretching blow molding large-sized container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a large-sized container to be stretching blow molded at a blowing mold position by omitting a mold opening/closing and mold clamping means of the preforming mold by always combining the blowing mold and a preforming mold and keeping the preforming mold open by a spring member. SOLUTION: A mold apparatus for stretching blow molding the large-sized container comprises the blowing mold 1 of the large-sized container divided into a pair of mold clamping plates 11 and mounted thereat, the preforming mold 7 of a side aligned telescopically in and out from between split molds of the mold 1, and an input/output unit 8 of the mold 7 provided at the mold opening/closing side of the mold 1. The mold apparatus further comprises a pair of support plates 88 movably supported to both sides of the front surface of a retractably movable plate 81 opposed to the mold 1 of the unit 8, and always elastically pressed outward by a spring member 89. The mold 7 is divided to the inside of the plate 88 and mounted. Opening of the mold 7 is maintained by the member 89 so that closing and clamping of the mold can be executed via the mold 1 by the plates 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold apparatus for stretch blow molding of a large container having a preformed mold of a bottomed parison injection-molded.

[0002]

It is extremely difficult to directly stretch blow-mold a large container from an injection-molded bottomed parison to form it, because of the draw ratio, etc. Conventionally, a preformed body having a bottomed parison as an intermediate is conventionally used. It is performed after preforming to a certain extent.

However, in practice, if the wall thickness of the stretched wall of the bottomed parison becomes significantly thicker than a normal case (4 mm or less), ordinary air blowing means will not allow the formation of the preformed body to be performed. Thickness is likely to occur, especially for resins that do not have self-healing properties such as polyethylene terephthalate. It often breaks during molding and does not form.

[0004] This preforming is provided separately from a blow mold for stretching blow molding of a bottomed parison container together with a mold clamping device and ancillary devices, so that the molding machine becomes large and the structure becomes complicated. Since the bottomed parison is temporarily stopped at the position of the preforming mold and preformed, and then transferred to the blow mold, it takes time and time compared to the case where preforming is unnecessary. In the molding means up to,
Although it is possible to mold a large container to some extent from the injection-molded bottomed preform, it has been very difficult to stretch blow mold a large container of about 20 liters.

The present invention has been conceived in order to solve the above-mentioned problems, and an object thereof is to provide a blow mold and a preforming mold even for stretch blow molding of a large container requiring preforming. Combining and maintaining the mold opening of the preforming mold by a spring member at all times, omitting the mold opening / closing and mold clamping means of the preforming mold, thereby enabling the large container without moving the preform. An object of the present invention is to provide a new large-sized stretch blow molding die apparatus capable of simplifying the configuration of a molding machine by enabling stretch blow molding.

[0006]

SUMMARY OF THE INVENTION According to the present invention, there is provided a blow mold for a large container divided and mounted on a pair of mold clamping plates, and a split mold of the blow mold which is juxtaposed so as to freely enter and exit. A preformed mold on the side of the mold, and a device for opening and closing the preformed mold provided on the opening and closing side of the blow mold. , While a pair of support plates are movably opposed to each other by supporting the base end portion,
The spring member provided over the inside of the base end portion constantly presses outward, and the preforming mold is divided and attached inside the spring member, and the preforming mold is kept open by the spring member, and the blowing is performed. It is configured such that the mold can be closed and clamped against the spring member by the mold clamping plate via the mold.

The blow mold comprises a pair of split molds mounted on the inner side of a mold clamping plate and a bottom mold which can be raised and lowered. A support rod of a preform is provided at the center of the bottom mold. The device is supported by a spring member charged in a plunger of a mold elevating device, and is provided so as to be able to come and go.

In the above construction, the preforming mold is arranged so as to freely enter and exit between the divided dies of the blowing mold, and the preforming mold is kept open by a spring member to close the blowing mold. And the mold clamping means can be used also as the mold closing and mold clamping means of the preforming mold, so that even if the container to be stretch blow molded is a large 20 liter container, the mold of the preforming mold can be used. Since a fastening device and ancillary devices are not required, the structure of the stretch blow molding machine is simplified by that much, and the manufacturing cost is reduced. In addition, since it is possible to shift from preforming to stretch blow molding of the container simply by moving the preforming mold without moving the preforming body, the number and time required to transfer the preforming body can be reduced, and the temperature drop due to the transfer can be prevented. Thus, the temperature of the preformed body maintaining the high temperature can be easily controlled.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawing, reference numeral 1 denotes a blow mold, which includes a pair of split molds 12 and 12 mounted inside mold clamp plates 11 and 11 which are openably and closably provided by ordinary mold clamping means, and a vertically movable mold. A half portion of the cavity 14 of the large container is recessed on the opposing surface of the split molds 12 and 12 and a half portion of the receiving port 19 of the lip mold 3 is provided on the upper portion. Is formed. At the center of the bottom mold 13, a support rod 15 of a preformed body described later is provided so as to freely protrude and retract. This support rod 1
4 is supported by a spring member 18 charged in a plunger 17 of an elevating device 16 of the bottom mold 13 as shown in FIG.

Reference numeral 2 denotes a bottomed parison, which is transferred to the upper part of the blow mold 1 while holding its mouth by a lip mold 3 after injection molding, and further lowered together with the transfer board 4 to open the split mold 12, 12 is located at the center. This bottomed parison 2
After the mold is closed, as shown in FIG. 4, the blow core 5 and the extension rod 5 are inserted from above through the lip mold 3 and the transfer plate 4 which are accommodated in the receptacle 19 at the upper part of the mold. You.

Reference numeral 7 denotes a preforming die for the bottomed parison 2, which is mounted on a movable plate 81 of an access device 8 disposed on a machine base on the opening and closing side of the blowing die 1. The access device 8 includes a base 82 fixed to the machine base, a movable seat plate 83 which is guided by guide rails on both sides of the upper surface of the base 82 and moves forward and backward on the base 82, and a front end of the movable seat plate 83. The movable plate 81 is provided vertically to face the blow mold 1 and the movable seat plate 83.
And a hydraulic drive device 85 for a movable plate 81 mounted on the rear end of the base 82 by connecting the distal end of a piston rod 86 to a joint member 84 protruding from the upper surface of the base plate 82.

A support shaft 8 is provided above and below the front surface of the movable plate 81.
7,87 are installed. A pair of support plates 88, 88 are vertically opposed to both ends of the support shafts 87, 87 so as to freely move the base ends 88a, 88a. This support plate 8
A spring member 89 is provided on the inner side of the base end of each of the base plates 8 and 88 with both ends abutting against the plate surface.
8, 88 are always repressed outward. Support plate 8
8, 88 except for the base ends 88a, 88a.
The split molds 71, 71 of the preforming mold 7 are mounted in the mold frame with a heat insulating plate 91 provided between the mold 71 and the support plate 88.

A half of the cavity 72 is recessed on the opposing surfaces of the split molds 71, 71, and the lip mold 3 is
Is formed at the same height as the receiving port 19 of the blow mold 1, and an insertion hole 74 for the support rod 15 is formed at the bottom center.

As shown in FIG. 2, the split molds 71, 71 are moved forward by the movable plate 81 together with the movable seat plate 83 when the piston rod 86 is extended, as shown in FIG. 1 can be inserted between the split molds 12, 12, and thereafter, the blow mold 1 is closed together with the mold clamping plates 11, 11, and the support plates 88, 88 are pressed from the outside, so that the split mold 71 can be inserted. , 71 together with the support plates 88, 88 are pressed inward against the spring member 89, and the mold can be closed and clamped as shown in FIG.

When the blow mold 1 is opened by retreating the mold clamping plates 11 and the pressing force is removed, the support plates 88 and 88 are pushed back by the spring member 89 and the split molds 71 and 71 are automatically moved. Then, when the piston rod 86 is driven to contract and the movable plate 81 is moved backward together with the movable seat plate 83, the preforming mold 7 is pulled back to the outside from between the split molds of the blow mold 1 in the mold open state. It is.

The stretch blow molding by the above mold apparatus will be described for a large container made of polycarbonate. First, a bottomed parison 2 having a stretched portion having a thickness of about 10 mm and being somewhat shorter than the final molded product is prepared. Injection molding. Although the bottomed parison 2 is not shown in the figure, the neck is held by the lip mold 3 after the injection and the mold is released from the injection mold and the core mold at a high temperature, and immediately the mold is opened together with the lip mold 3 by the transfer board 4. It is transferred to a certain upper part of the blow mold 1.

After the transfer is completed, the preforming mold 7 heated to 140 ° C. to 150 ° C. is moved together with the supporting plates 88 and 88 by the extension driving of the piston rod 86 between the split molds 12 and 12 of the blow mold 1. (See FIG. 2). Next, the bottomed parison 2 is moved down together with the lip mold 3 and the transfer board 4 to be positioned at the center of the preforming mold 7 in the mold open state, and then the mold clamping plates 11 are moved forward. Injection mold 1
Temporary mold closing and mold clamping. As a result, as shown in FIG. 3, the preforming mold 7 is closed and clamped via the split molds 12, 12, and the support rod 1 projecting from the bottom mold 13 when the mold is closed.
5 fits into the insertion hole 74 at the bottom of the preforming mold 7.

When the clamping of the preforming die 7 is completed, FIG.
As shown in the figure, the blowing core 5 and the extension rod 6 are inserted from the upper part of the transfer board through the lip mold 3 to the neck and the bottom of the bottomed parison 2, and axial extension by the extension rod 6 is performed.
The expansion and contraction by press-in and release of air are performed. The injection and release of air are intermittent, and the axial stretching is performed only by the initial injection of air. By this extension, the bottom of the bottomed parison 2 is held between the extension rod 6 and the support rod 15.

The pressure of the air may be about 2 kgf, and the press-in and discharge are performed by operating the valve in about 4 to 6 times, and the discharge facilitates the contraction of the expanded portion except for the internal pressure of the bottomed parison 2. It is important that the air injection time is extremely short for the purpose of preventing partial significant expansion, but the final injection is relatively long, for example, about 4 seconds to completely expand the entire cavity. It is necessary. After forming the cylindrical preform 10 having a thickness of about 5 mm in this manner, the process proceeds to stretch blow molding of the final molded product.

After completion of the preforming, the mold clamping plates 11, 11 are retracted to open the blow mold 1, and the pressing force of the preforming mold 7 on the split dies 71, 71 is removed. The dies 71, 71 are automatically opened to the original state by the spring pressure while leaving the preformed body 10 as it is. After the mold is opened, the piston rod 86 of the access device 8 is driven to contract, and the preforming mold 7 is moved backward together with the movable plate 81 to return to the original position of the side of the blow mold. In the center of the blow mold 1 in the mold open state, the preform 10 remains supported by the support rod 15. This prevents drawdown of the preform 10 due to high temperature.

Then, the blow mold 1 is closed again by the mold clamping plates 11 and 11 to perform mold clamping, and the process shifts to stretch blow molding of the preform 10 by axial extension by the stretching rod 6 and expansion by air pressure. . Air blowing is low pressure primary,
The second step is performed separately from the high pressure secondary of 8 kgf or more, and simultaneously with the expansion at a stretch by the secondary pressure or after that, the bottom mold 13 is raised to form the bottom. Due to the rise of the bottom mold 13, the support rod 15 is settled in the bottom mold against the spring member 18, and a large container 100 having a thickness of about 1.2 mm is formed as a final molded product.

[Brief description of the drawings]

FIG. 1 is a partially longitudinal front view of a mold apparatus for stretch blow molding of a large container according to the present invention when the mold is opened.

FIG. 2 is a plan view of a main part in a state where a preforming die is inserted between blow-in dies.

FIG. 3 is a plan view of a main part in a mold closed state of the same.

FIG. 4 is a schematic longitudinal sectional view showing a molding state of a preform.

FIG. 5 is a schematic longitudinal sectional view of the blow mold after the preforming mold has been sent out.

FIG. 6 is a schematic vertical sectional view of a blow mold showing a molding state of a large container.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 blow mold 2 bottomed preform 3 lip mold 6 stretch rod 7 preform mold 8 access device 10 preform 11 mold clamping plate 12 blow mold split mold 13 bottom mold 14 large container cavity 15 support rod Reference Signs List 16 Bottom type elevating device 17 Plunger 18 Support rod spring member 81 Movable plate 82 Base 83 Movable seat plate 84 Joint member 85 Hydraulic drive 86 Piston rod 87 Support shaft 88 Support plate 89 Spring member for opening mold

Claims (2)

[Claims] 1. A blow mold for a large container which is divided and attached to a pair of mold clamping plates, a preforming mold on a side portion which is juxtaposed so as to be able to enter and exit between the divided molds of the blow mold, and a blow mold. A pre-molding die access device provided on the mold opening / closing side of the mold, and a pair of support plates movably mounted on both front sides of a movable plate that can move forward and backward facing the blow mold of the access device. The bearings are mounted opposite to each other, and are constantly resiliently pressed outward by a spring member provided over the inside of the base end.The preforming mold is divided and attached to the inside thereof, and the preforming mold is attached by the spring member. Stretch blow molding of a large container, characterized in that the mold is maintained in an open state, and the mold can be closed and clamped against a spring member by a mold clamping plate via the blow mold. Mold equipment. 2. The blow mold comprises a pair of split molds mounted on the inside of a mold clamping plate, and a bottom mold capable of moving up and down. A support rod of a preform is provided at the center of the bottom mold. The mold apparatus for stretch blow molding of a large container according to claim 1, characterized in that the mold apparatus is supported by a spring member charged in a plunger of a bottom type elevating device and is provided so as to be freely retractable.