JPH0649329B2 - Method and device for adjusting temperature of parison in injection stretch blow molding - Google Patents

Description

TECHNICAL FIELD The present invention relates to a temperature adjusting method and apparatus for a parison in injection stretch blow molding.

[Prior Art] In the hot parison method, which is one method of biaxial stretch blow molding, generally, the parison is molded by injection molding in the first step, and the temperature is adjusted by heating the parison in the second step. Stretching and blowing are performed in the third step, mold opening and product removal are performed in the fourth step,
These steps are carried out continuously.

The temperature adjustment in the second step is intended to obtain the temperature distribution of the parison necessary for forming a container having a desired wall thickness distribution.

An example of such a parison temperature adjusting device is the type disclosed in Japanese Patent Laid-Open No. 63-207630.
In this device, the parison 1 held by the neck mold 4 is housed in the cavity 3 of the temperature control pot 2 composed of the temperature control blocks 2A to 2E arranged in multiple stages, and further inserted into the neck mold 4. Air is press-fitted into the parison 1 through the air blowing ring 6 in the rod 5, and the pressure of this air causes the parison 1 to entirely contact the inner wall of the cavity 3 to adjust the temperature. The temperature of the temperature adjusting pot 2 is set by the water passage 7 through which the temperature adjusting fluid passes.

Further, since the lower neck portion 1a of the parison 1 has a smaller wall thickness than the body portion 1b and therefore has a smaller amount of heat retained than the body portion 1b and is difficult to be stretched, it is necessary to heat and adjust the lower neck portion 1a at a higher temperature than the body portion 1b. A heater 8 is provided around the lower neck 1a.

[Problems to be Solved by the Invention] However, in the temperature adjusting device of the above type,
Since the heater 8 is in contact with the lower neck portion 1a of the parison 1 and the heater 8 needs to be set to a considerably high temperature, the outer surface of the lower neck portion 1a of the parison 1 is the heater 8.
There is a problem that the parison 1 may be deformed or damaged when the parison 1 is detached from the temperature adjustment pot 2 by being welded to the inner wall surface of the parison 1.

An object of the present invention is to obtain a hollow container capable of accurately and quickly controlling the temperature distribution of a parison, having a desired wall thickness and shape, and having excellent properties such as impact strength, thermal stability, and barrier properties. (EN) Provided is a parison temperature control method and device capable of controlling the temperature.

[Means for Solving the Problem] In the first invention of the present invention, in a parison formed by injection molding, a first stretched portion requiring a high adjustment temperature is in a non-contact state with the first stretched portion. The heating temperature is adjusted by the radiant heat of the first temperature adjusting unit disposed in the second stretching unit, which requires a lower adjusting temperature than the first stretching unit in the parison, and contacts the second stretching unit. The present invention relates to a temperature adjusting method for a parison, wherein the temperature is adjusted by a second temperature adjusting section arranged in a state.

A second invention of the present invention is, in a temperature adjusting device for a parison in injection stretch blow molding, wherein a parison holding part for holding a neck part of the parison formed by injection molding and an outer periphery of the first extending part of the parison are provided. A first temperature adjusting part, which is arranged apart from the extending part and has a heating means, and a second temperature adjusting part, which is arranged in contact with the outer periphery of the second extending part of the parison and has the temperature adjusting means. And a temperature adjusting device for a parison, which includes an air blowing part for supplying air into the parison from an opening of the parison.

[Operation] In the present invention, it is composed of a portion having a small wall thickness and difficult to be stretched or a portion requiring a large stretching ratio, and therefore, it is necessary to control the temperature at a higher temperature than the second stretching portion composed of other portions. Since the temperature of the second stretched portion having a gap is adjusted by the radiant heat of the first temperature adjusting portion provided separately from the first stretched portion, contact between the parison and the temperature adjusting portion may occur. Deformation and damage of the parison are prevented, and as a result, the first stretched portion can be sufficiently and quickly heated to the target temperature.

As described above, the first stretching part requiring a higher adjusting temperature and the second stretching part requiring a lower adjusting temperature as compared to the first stretching part are different in the first temperature. By adjusting the adjusting section and the second temperature adjusting section, the temperature cloth of the parison can be surely and quickly set to a desired state.

Here, the "temperature adjustment" means not the temperature of the parison itself but the set temperature of the temperature adjustment unit.

[Embodiment] First Embodiment FIG. 1 is a sectional explanatory view showing a first embodiment of the present invention.

The temperature adjusting device 100 according to the first embodiment has a substantially box-like shape as a whole, and the second temperature adjusting units 20 and 20 stacked in two stages below the upper temperature adjusting unit 20. The first temperature adjusting unit 10 and the first temperature adjusting unit 10, which are stacked in two steps, and the neck mold 50 that functions as a parison holding unit are provided.

The first temperature adjusting unit 10 has a ring-shaped adjusting unit body 1 having a hollow portion 16 for accommodating the parison P therein.
2 and a belt-shaped heater 14 arranged along the circumferential direction of the outer circumference of the adjusting portion main body 12.

Then, the first temperature adjusting unit 10 has the adjusting unit main body 12
The inner wall of the parison P corresponds to the lower part of the neck of the first extended portion P
1, and the diameter of the hollow portion 16 is defined so that the outer surface of the first extending portion P1 and the inner wall surface of the adjusting portion main body 12 have a predetermined distance.

Here, the first stretched portion P1 is formed to be thinner than the second stretched portion P2 that constitutes the lower body of the first stretched portion P1 because of the mold structure and the like, and the amount of heat retained is smaller, so that the desired parison temperature is maintained. In order to obtain it, a higher adjustment temperature than the second stretched portion P2 is required.

The second temperature adjusting section 20 is composed of an adjusting section main body 22 having a hollow portion 26 therein, and a groove formed along the circumferential direction of the outer circumference of the adjusting section main body 22, for adjusting the temperature of water or the like. It is composed of a fluid passage 24 through which a fluid flows, and a ring-shaped frame 26 fitted on the outside of the adjusting portion main body 22.

Then, the hollow parts 26, 26 of the adjusting part bodies 22, 22
Is a cavity C formed by these hollow portions 26.
It has a shape corresponding to the outer shape of the second extended portion P2 so that the second extended portion P2 of the parison P is accommodated therein.

Further, a ring-shaped heat insulating member 30 is interposed between the temperature adjusting units 10, 10, 20, 20. By providing such a heat insulating member 30, the heat control of each temperature adjusting unit can be performed more reliably.

Also, the neck portion P3 of the parison P is the neck portion P3.
And is held by a neck mold 50 that transfers the parison P to each process position. A core portion 40 whose lower end is inserted into the parison P is provided at the center of the neck mold 50. The core portion 40 is formed by concentrically inserting and fixing an air blowing portion 44 having an air hole 44a and a rod-shaped cartridge heater 46 inside a ring-shaped core body 42. Further, the air blowing portion 44 and the cartridge heater 46 are provided with their lower ends protruding into the parison P, and further, a ring-shaped internal heating portion 48 is provided on the outer periphery of the tip of the air blowing portion 44.

Next, the operation of the first embodiment will be described.

The parison P molded by injection molding is a neck mold 50.
The parison P is housed in the cavity C of the temperature adjusting device 100 by being transferred to a position above the temperature adjusting device 100 by further lowering the neck mold 50 or raising the temperature adjusting device 100.

Then, by supplying air into the parison P via the air blowing portion 44, the second extending portion P2 of the parison P and the inner wall of the adjusting portion main body 22 of the second temperature adjusting portion 20 are brought into contact with each other to conduct heat. The temperature is adjusted by. At this time,
If the pressure of the air supplied from the air blowing unit 44 is too large, the first extending portion P1 expands and the first temperature adjusting unit 10
Therefore, the pressure of the air needs to be controlled to a pressure in the range where such a phenomenon does not occur, for example, a low pressure of about 1 to 5 kg / cm ² .

In addition, the first temperature adjusting unit 10 uses the heater 14 to
The temperature of the parison P is adjusted by the fluid in the fluid passage 24 in the temperature adjusting section 20 and by the heater 46 in the internal heating section 48 to adjust the temperature of the parison P. Then, at the stage where the temperature adjustment of the parison P is completed, the parison P is taken out from the temperature adjusting device 100 and transferred to the next stretching and blowing step.

A feature of the present invention is that the first stretched portion P1 and the second stretched portion P2, which have different appropriate adjustment temperatures depending on the thickness and shape of the parison or the thickness and shape of the final molded product,
The temperature distribution of the parison P can be properly and promptly controlled by adjusting the temperature by the individual temperature adjusting units 10 and 20, respectively. That is,
For the first stretched portion P1 which is thin and has a small amount of heat and requires a higher regulated temperature, the temperature is regulated by the radiant heat of the first temperature regulated portions 10, 10 provided in a non-contact state with the first stretched portion P1. By doing so, it is possible to prevent the softened parison wall from being deformed or scratched by coming into contact with the temperature adjusting portion, while the second extending portion P2 that requires a relatively low adjusting temperature is used. By adjusting the temperature by heat conduction by the contact of the second temperature adjusting section 20, the temperature of the entire parison P can be adjusted accurately and quickly.

In addition, in the first embodiment, the first temperature adjusting unit 10,
Since 10 and the internal heating unit 48 heat the radiant heat from both inside and outside of the first stretched portion P1, the first stretched portion P1 can be quickly and uniformly heated to an appropriate temperature. As a result, the first stretched portion P tends to have insufficient properties such as impact strength, thermal stability, and barrier property due to insufficient stretching.
The stretching of 1 can be achieved more reliably.

Second Embodiment FIG. 2 is a sectional explanatory view showing a second embodiment. In addition,
In the second embodiment and the third embodiment described later, members having the same or similar functions to those of the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

The temperature adjusting device 200 of the second embodiment is basically the same as the first embodiment.
The device 100 has the same configuration and the same function as the device 100 of the embodiment, but is different in the following points. That is, the far infrared ray generating portions 12a and 48a which are easily absorbed by the first extending portion P1 are provided on the surfaces of the adjusting portion main body 12 and the internal heating portion 48 of the first temperature adjusting portion 10, respectively. By providing such far-infrared ray generating sections 12a and 48a, it is possible to efficiently heat the first extending section P1 in a short time.

Third Embodiment FIG. 3 is a sectional explanatory view showing a third embodiment.

In the temperature adjusting device 300 of the third embodiment, not only the lower part of the neck where the wall thickness changes, but also the part where the draw ratio is desired to be higher than the other parts in the body part where there is no difference in wall thickness is the first draw part P1.
The first temperature adjusting unit 10 is provided at a plurality of points, and thus the first temperature adjusting unit 10 is provided.
Different from the embodiment. In addition, in the third embodiment,
Since the thickness difference of the parison P is not so large, the internal heating part 48 in the first embodiment is not provided.

Although the embodiments of the present invention have been described above, the present invention is not limited to these and various modifications can be made within the scope of the invention.

For example, in the parison P, the first stretched portion P1 is generally constituted by a lower neck portion having a difference in wall thickness, but the present invention is not limited to this, and the lower neck portion and a part of the body portion or the body portion. It may be composed of a plurality of locations. Also, the first
Shapes of the temperature adjusting unit 10 and the second temperature adjusting unit 20 of
The arrangement, the number, etc., depend on the arrangement of the extending portions P1 and P2,
It is appropriately set according to the size, shape, wall thickness, etc. of the parison P and the final molded product.

[Advantageous Effects of the Invention] According to the present invention, by providing separate temperature adjusting sections for the first stretching section that requires a high regulation temperature and the second stretching section that requires a low regulation temperature, Temperature of parison that can control temperature distribution of parison accurately and quickly, has desired wall thickness and shape, and has excellent properties such as impact strength, thermal stability and barrier property. An adjusting method and its apparatus can be provided.

[Brief description of drawings]

FIG. 1 is a sectional explanatory view showing a first embodiment of the temperature adjusting device of the present invention, FIG. 2 is a sectional explanatory view showing a second embodiment of the temperature adjusting device of the present invention, and FIG. FIG. 4 is a sectional explanatory view showing a third embodiment of the temperature adjusting device of the invention, and FIG. 4 is a sectional explanatory view showing an example of a conventional temperature adjusting device. 10 ... 1st temperature control part, 20 ... 2nd temperature control part, 30 ... Thermal insulation member, 48 ... Internal heating part, P ... Parison, P1 ... 1st extension part, P2 ... 2nd extension part, C ... cavity.

Claims (3)

[Claims] 1. A first stretched portion of a parison formed by injection molding, which requires a high adjustment temperature, comprises:
The second stretching portion, which is adjusted in heating temperature by radiant heat of the first temperature adjusting portion arranged in a non-contact state with the stretching portion, is required to have a lower regulation temperature than the first stretching portion in the parison, A temperature adjusting method for a parison, characterized in that the temperature is adjusted by a second temperature adjusting section arranged in contact with the first stretching section. 2. A temperature adjusting device for a parison in injection stretch blow molding, comprising: a parison holding part for holding a neck part of the parison formed by injection molding; and a gap between the parison on the outer periphery of the first stretched part of the parison. And a second temperature adjusting part having a temperature adjusting means, and a second temperature adjusting part having a temperature adjusting means. A parison temperature adjusting device, comprising: an air blowing unit that supplies air into the parison from an opening. 3. The parison temperature adjusting device according to claim 2, wherein the heating means of the first temperature adjusting portion has a far infrared ray generating portion which is easily absorbed by the second extending portion of the parison.