JPH03290225A - Parison temperature-regulating method and device in injection-orientation blow molding - Google Patents

Abstract

PURPOSE:To set surely and quickly the temperature distribution of a parison at a desired state by regulating the first orientating part with the necessity of high regulating temperature and the second orientating part with the necessity of low regulating temperature by the first temperature-regulating part and the second temperature- regulating part with different types. CONSTITUTION:The neck part P3 of a parison P is held by a neck mold 50. By feeding air into the parison P through an air-blowing part 44, a second orientating part P2 brought in contact with the inner wall of the regulating body 22 of a second temperature-regulating part 20, whereby temperature regulation is achieved by heat- conduction. A first temperature-regulating part 10 by a heater 14 and the second temperature-regulating part 20 by the fluid in a fluid path and further and internal heating part 48 by a heater 46 are respectively set a prescribed regulating temperatures, whereby the temperature-regulation of the parison P is carried out. In another method, the heating of the first orientating part P1 may be effectively achieved in short time by providing the farinfrared ray-generating parts 12a, 48a on the surfaces of the regulating body 12 and an inner heating part 48 of the first temperature-regulating part 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method and apparatus for adjusting the temperature of a parison in injection stretch blow molding.

[Prior Art] In the hot parison method, which is a method of biaxial stretch blow molding, the parison is generally formed by injection molding in the first step, and the temperature is adjusted by heating the parison in the second step. In the third step, stretch blowing is performed, and in the fourth step, the mold is opened and the product is taken out, and these steps are performed continuously.

The temperature adjustment in the second step is aimed at obtaining a temperature distribution of the parison necessary for molding a container with a desired wall thickness distribution.

As such a parison temperature adjustment device, there is a type disclosed in, for example, Japanese Patent Laid-Open No. 133-207 [10]. In this device, a parison 1 held in a neck mold 4 is placed in temperature control blocks 2A to 2 arranged in multiple stages.
Place it in the cavity 3 of the temperature adjustment pot 2 consisting of E,
Further, air is press-fitted into the parison 1 through an air blowing ring 6 in a rod 5 inserted into the neck mold 4,
The temperature of the parison 1 is adjusted by bringing the entire parison 1 into contact with the inner wall of the cavity 3 by the pressure of this air. The temperature of the temperature adjustment pot 2 is set by a water channel 7 through which a temperature adjustment fluid passes.

Further, the 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 than the body portion 1b and is difficult to stretch, so it is necessary to heat and adjust the neck portion 1a at a higher temperature than the body portion 1b. A heater 8 is provided around the lower neck portion 1a.

[Problem to be solved by the invention] However, in the above type of temperature adjustment device,
The heater 8 is in contact with the neck lower part 1a of the parison 1, and since the heater 8 needs to be set at a fairly high temperature, the outer surface of the neck lower part 1a of the parison 1 is in contact with the heater 8.
There was a problem in that the parison 1- could be deformed or damaged when the parison 1 was removed from the temperature adjustment pot 2.

The purpose of the present invention is to obtain a hollow container that can accurately and quickly control the temperature distribution of the parison, has a desired wall thickness and shape, and has excellent properties such as impact strength, thermal stability, and barrier properties. An object of the present invention is to provide a method and apparatus for adjusting the temperature of a parison.

[Means for Solving the Problems] A first aspect of the present invention is that the first stretched portion, which requires a high adjustment temperature in a parison formed by injection molding, is in a non-contact state with the first stretched portion. A second stretched portion whose heating temperature is adjusted by radiant heat of the first temperature adjustment portion disposed in the parison and which requires a lower adjustment temperature than the first stretched portion in the parison is in contact with the second stretched portion. The present invention relates to a method for adjusting the temperature of a parison, characterized in that the temperature is adjusted by a second temperature adjusting section disposed in the same state.

A second aspect of the present invention is a parison temperature adjustment device in injection stretch blow molding, which includes: a parison holding part that holds a neck part of a parison formed by injection molding; and a parison holding part that holds a neck part of a parison formed by injection molding; a first temperature adjustment section that is disposed apart from the stretched section and has a heating means; a second temperature adjustment section that is disposed in contact with the outer periphery of the second stretched section of the parison and has a temperature adjustment means. and an air blowing section that supplies air into the parison from an opening in the parison.

[Function] In the present invention, the second stretched part consists of a part with a small wall thickness that is difficult to stretch or a part that requires a large stretching ratio, and therefore needs to be temperature-controlled at a higher temperature than the second stretched part, which consists of other parts. For a certain first stretched section, the temperature is adjusted by the radiant heat of the first temperature adjustment section provided apart from this first stretched section, so the temperature is adjusted by the contact between the parison and the temperature adjustment section. Deformation and damage to the parison are prevented, and as a result, the first stretching section can be sufficiently and quickly heated to the desired temperature.

In this way, the first stretching section, which requires a higher adjustment temperature, and the second stretching section, which requires a lower adjustment temperature compared to the first stretching section, are set to different temperatures at different temperatures. By adjusting the temperature distribution using the adjustment section and the second temperature adjustment section, the temperature distribution of the parison can be set to a desired state reliably and quickly.

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

[Example] First Example FIG. 1 is a cross-sectional explanatory diagram showing a first example of the present invention.

The temperature adjustment device 100 of the first embodiment has a substantially box-like overall shape, and includes a second temperature adjustment section 20.20 stacked in two stages at the bottom thereof, and a second temperature adjustment section 20 at the upper level. It has a first temperature adjustment section 10.1.0 stacked in two stages on top, and a neck mold 5o that functions as a parison holding section.

The first temperature adjustment section 10 has a ring-shaped adjustment section main body 1 having a hollow section 16 for accommodating the parison P therein.
2, and a belt-shaped heater 14 disposed along the circumferential direction of the outer periphery of the adjustment section main body 12.

The first temperature adjustment section 10 has a first temperature adjustment section main body 12.
The first extension part P whose inner wall corresponds to the lower neck part of the parison P
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 adjustment portion main body 12 have a predetermined distance.

Here, the first elongated portion P1 is formed thinner than the second elongated portion P2 constituting the lower body due to the mold structure and has a smaller heat capacity, so that the desired parison temperature cannot be maintained. In order to obtain this, a higher adjustment temperature than the second stretching part P2 is required.

The second temperature adjustment section 20 consists of an adjustment section main body 22 having a hollow part 26 inside and a groove formed along the circumferential direction of the outer periphery of this adjustment section main body 22, and is used for temperature adjustment of water etc. It is composed of a fluid path 24 through which fluid flows, and a ring-shaped frame 26 fitted on the outside of the adjustment section main body 22.

And the hollow part 26.26 of the adjustment part main body 22.22
is the cavity C formed by these hollow parts 26
It has a shape corresponding to the outer shape of the second extending portion P2 so that the second extending portion P2 of the parison P is accommodated therein in a contacting state.

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

In addition, the neck portion P3 of the parison P is
The parison P is held by a neck mold 50 that molds the parison P and transports it to each process position. A core portion 4o whose lower end is inserted into the parison P is provided at the center of the neck mold 5o. The core section 40 is formed by inserting and fixing an air blowing section 44 having an air hole 44a and a rod-shaped cartridge heater 46 concentrically into a ring-shaped core body 42. The air blowing section 44 and the cartridge heater 46 are provided with their lower ends protruding into the parison P, and a ring-shaped internal heating section 48 is provided on the outer periphery of the tip of the air blowing section 44.

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

Parison P molded by injection molding has neck type 50
The parison P is transferred to above the temperature adjustment device 100 by further lowering the neck mold 50 or by raising the temperature adjustment device 100 to house the parison P in the cavity C of the temperature adjustment device 100.

Then, by supplying air into the parison P through the air blowing part 44, the second extended part P2 of the parison P is brought into contact with the inner wall of the adjustment part main body 22 of the second temperature adjustment part 20, and heat conduction is carried out. The temperature is adjusted by. At this time,
If the pressure of the air supplied from the air blowing section 44 is too high, the first extension section P1 expands and the first temperature adjustment section 1o
The air pressure must be within a range where this does not occur, for example 1 to 5 kg/
It is necessary to control the pressure to be as low as colt.

Further, the first temperature adjustment section 10 is controlled by the heater 14 to
The temperature adjustment section 20 is set to a predetermined adjustment temperature by the fluid in the fluid path 24, and the internal heating section 48 is set to a predetermined adjustment temperature by the heater 46, so that the temperature of the parison P is adjusted. Then, when the temperature adjustment of the parison P is completed, the parison P is extracted from the temperature adjustment device 100 and transferred to the next stretching blowing process.

0 The characteristic feature of the present invention is that the first stretched portion P1 and the second stretched portion P2 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 appropriately and quickly controlled by adjusting the temperature using separate temperature adjusting sections 10 and 20, respectively. That is,
For the first stretched part P1, which is thin and has a small amount of heat and requires a higher temperature adjustment, the temperature is increased by the radiant heat of the first temperature adjustment part 10, 1.0, which is provided in a non-contact state. By performing the adjustment, it is possible to prevent deformation and damage caused by the softened parison wall coming into contact with the temperature adjustment part. By adjusting the temperature by heat conduction through contact with the second temperature adjusting section 20,
The temperature of the entire parison P can be adjusted accurately and quickly.

Further, in the first embodiment, the first temperature adjustment section 10,
10 and the internal heating section 48 heat the first stretched section P1 from both the inside and outside using radiant heat, so the first stretched section P1 can be quickly and evenly heated to an appropriate temperature. As a result, it is possible to more reliably achieve stretching in the first stretched portion P1, where properties such as impact strength, thermal stability, and barrier properties tend to be insufficient due to insufficient stretching.

Second example FIG. 2 is a cross-sectional explanatory diagram showing the second embodiment.

In addition, in the second example and the third example described later,
The same reference numerals are given to members having the same or similar functions as those in the first embodiment, and detailed explanation thereof will be omitted.

The temperature adjustment device 200 of the second embodiment basically includes the first
Although it has the same configuration and the same functions as the device 100 of the embodiment, it differs in the following points. That is, far-infrared ray generating parts 12a and 48a, which are easily absorbed by the first extension part P1, are provided on the surfaces of the adjustment part main body 12 and the internal heating part 48 of the first temperature adjustment part 10, respectively. By providing such far-infrared ray generating parts 12a and 48a, it is possible to heat the first stretched part P1 efficiently in a short time.

Third embodiment FIG. 3 is a cross-sectional explanatory diagram showing a third embodiment.

In the temperature adjustment device 300 of the third embodiment, not only the lower part of the neck where the wall thickness changes, but also a part of the trunk where there is no difference in wall thickness, where the stretching ratio is desired to be higher than other parts, are set as the first stretching part P1, and a plurality of This embodiment differs from the first embodiment in that a first temperature adjustment section 10 is provided at the location.

In addition, in the third embodiment, since the difference in wall thickness of the parison P is not so large, the internal heating section 4 in the first embodiment
8 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 gist of the invention.

For example, in the parison P, the first extended portion P1 is generally constituted by a lower neck portion with a difference in wall thickness, but is not limited to this, and is composed of a lower neck portion and a part of the body portion, or a portion of the body portion. It may be composed of multiple locations. Also, the first
The shape, number, etc. of the temperature adjustment parts 10 and 3 and the second temperature adjustment part 20 depend on the size, shape, and wall thickness of the parison P and the final molded product, as well as the arrangement of the extended parts PL and P2. etc., as appropriate.

[Effects of the Invention] According to the present invention, by providing separate temperature adjustment sections for the first stretching section that requires a high adjustment temperature and the second stretching section that requires a low adjustment temperature, The parison temperature can accurately and quickly control the temperature distribution of the parison, making it possible to obtain a hollow container with the desired wall thickness, shape, and excellent properties such as impact strength, thermal stability, and barrier properties. A method and apparatus for adjustment can be provided.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional explanatory diagram showing a first embodiment of the temperature regulating device of the present invention, FIG. 2 is a cross-sectional explanatory diagram showing a second embodiment of the temperature regulating device of the present invention, and FIG. FIG. 4 is a cross-sectional explanatory view showing an example of a conventional temperature adjusting device. FIG. DESCRIPTION OF SYMBOLS 10... 1st temperature adjustment part, 20... 2nd temperature adjustment part, 30... heat insulation member, 48... internal heating part, P... parison, P]... 1st- extension part, P2... second extension part, C... cavity.

Claims (3)

[Claims] (1) In a parison formed by injection molding, the first stretched section that requires a high temperature adjustment is heated by the radiant heat of the first temperature adjustment section that is disposed in a non-contact state with the first stretched section. temperature regulated and said first in the parison.
A parison characterized in that the temperature of the second stretched part, which requires a lower adjustment temperature than the stretched part, is adjusted by a second temperature adjustment part disposed in contact with the second stretched part. Temperature adjustment method. (2) A parison temperature adjustment device in injection stretch blow molding, comprising: a parison holding part that holds the neck part of the parison formed by injection molding; and a parison holding part that holds the neck part of the parison formed by injection molding; a first temperature adjustment section that is arranged and has a heating means; a second temperature adjustment section that is arranged in contact with the outer periphery of the second extending section of the parison and has a temperature adjustment means; and an opening of the parison. 1. An air blower for supplying air into the parison; and a parison temperature adjustment device. (3) A parison temperature adjustment device according to claim (2), wherein the heating means of the first temperature adjustment section has a far-infrared generation section that is easily absorbed by the first stretched section of the parison.