JPH05169522A - Parison mold - Google Patents

Abstract

PURPOSE:To provide a parison mold for injection blow molding, with which a parison having the exact temperature distribution as is set can be molded. CONSTITUTION:At the periphery of cooling cores 37, which are brought into floated state, clearance is formed between the cores and slit mold main bodies 31. Thus, the heat transfer between the cooling core 37 and the split mold main body 31 is reduced, resulting in realizing the favorable temperature distribution of parison.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parison molding die used for injection blow molding suitable for manufacturing resin boots, resin containers and the like, and more particularly to a cooling for partially cooling the parison. The present invention relates to a parison molding die having a nest.

[0002]

2. Description of the Related Art Injection blow molding of this kind is
Generally, the injection blow molding apparatus 10 as shown in FIG. 4 is used as follows.

First, the core 5 is formed by using the parison molding die 300.
Parison 70 is injection molded on top of 0. Next, the molded parison 70 is placed in the blow mold 40 together with the core 50, and air pressure is applied to the parison 70 from the inside to shape it into a desired shape. Then, the attached parison 70 is released from the core 50. Thereafter, the temperature of the core 50 is adjusted in preparation for the next molding. The released parison 70 is
After undergoing predetermined processing, it is made into a product.

As a conventional parison molding die 300, one having two split dies 30 and 30 as shown in FIG. 5 has been used. Hereinafter, this conventional parison molding die 30
0 will be described.

The split molds 30 and 30 form a cavity 34 together with the core 50. The cavity 34 is for receiving the molten resin injected from the injection unit 20 and forming the parison 70.

Each split mold 30 has a split mold main body 31 heated by a heater, and a cooling insert 3 fixed in the split mold 31.
It has 2.33. The cooling inserts 32 and 33 are provided with water passage holes 35 for flowing cooling water. The cooling inserts 32 and 33 are used to sufficiently cool and solidify the parison 70 formed in this portion and prevent the parison 70 from being deformed in the subsequent blowing step. Cooling insert 32
A recess is provided around 33 to reduce heat transfer with the split mold main body 31.

Reference numeral 36 is a sprue.

[0008]

However, in the above-mentioned conventional parison molding die 300, since the cooling inserts 32 and 33 are always in contact with the split mold main body 31, heat transfer is large, and at the boundary between the two. The temperature was higher than the set temperature on the cooling inserts 32 and 33 side and lower than the set temperature on the split mold main body 31 side.

And, such a parison molding die 300
Since the parison 70 molded by the above also has a similar temperature distribution, the parison 70 in the portion formed by the cooling inserts 32 and 33 is not sufficiently solidified and is deformed in the blowing process, or conversely cracks. There was a problem that the viscosity of the parison 70 formed in the mold main body 31 was increased and the parison 70 was not sufficiently shaped in the blowing process.

[0010]

In order to solve the above-mentioned problems, the present invention provides a parison molding die which is used for injection blow molding and is composed of a plurality of split molds, wherein the split mold is mainly a split mold. And a cooling insert arranged in the split mold main body for partially cooling the parison, and a floating device for floating the cooling insert from the split mold main body and opening a gap between the two when the mold is opened. The parison molding die is used.

[0011]

In the parison molding die of the present invention, the cooling insert for partially cooling the parison is floated from the split mold main body when the mold is opened, and a gap is provided between the split mold main body and the cooling insert. It has a floating device.

Therefore, the heat transfer between the cooling insert and the split mold main body can be prevented by the gap when the mold is opened, and the deviation from the set temperature at the boundary between the two can be reduced. In the parison formed by the parison molding die of the present invention, the portion formed by the cooling insert is sufficiently cooled and solidified, and the portion formed mainly by the split mold has a sufficiently low viscosity. Problems in the blowing process can be solved.

[0013]

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

The parison molding die 300 of this embodiment is used to mold the parison 70 for a constant velocity joint boot of an automobile, and is made up of two split molds 30 and 30 having the same structure. Demarcated.

Each split mold 30 comprises a split mold main body 31 heated to 125 ° C. by a heater (not shown) and cooling inserts 32 and 37 whose temperature is set to 55 ° C. by cooling water. I am trying.

The split mold main body 31 is for forming the central portion of the parison 70 (which is formed into a bellows shape in the blowing step), and the cooling inserts 32 and 37 are the inner circumferences of both ends of the parison 70. It is for forming ribs (which will become sealing ribs in the finished boot product) and the like. One cooling insert 3
2 is fixed to the split main body 31 as in the conventional case,
The other cooling insert 37 is arranged in the split mold main body 31 so as to be movable in the vertical direction in the figure.

The cooling insert 37 has four side surfaces inclined with respect to the mold splitting direction (vertical direction in the figure). Cooling insert 37
A compression coil spring 38 is arranged between the split main body 31 and the split mold main body 31 and urges the compression coil spring 38 away from each other. Also split type 3
1, a headed pin 39 penetrating the cooling insert 37 is fixed, and the moving stroke of the cooling insert 37 is restricted by the head of the pin 39. In this embodiment, the pin 38 and the compression coil spring 38 form a floating device.

Further, the cooling insert 37 is provided with a nipple 80 which projects from the side surface of the split mold 31 and is connected to the water passage hole 35, so that the cooling water can pass therethrough. In addition, split type main body 3
In order to enable the cooling insert 37 to move up and down together with the nipple 80, a hole 81 having a diameter larger than that of the nipple 80 is provided.
Is provided.

Next, a molding process using the parison molding die 300 will be described.

First, the parison molding die 300 is shown in FIGS.
The mold is opened as shown in. Then, the cooling insert 37 of each split mold 30 moves in a direction away from the split mold main body 31 by the action of the spring 38. At this time, since all the side surfaces of the cooling insert 37 are inclined, the cooling insert 31 is in a state of being floated and supported by the split mold main body 31, that is, the cooling insert 37 and the split mold main body 31.
A gap 90 is formed between and. Therefore, in this mold open state, the cooling insert 37 and the split mold main body 31
Almost no heat transfer occurs between and.

Next, the core 50 is placed between the split molds 30 and 30 and the mold is clamped. Then, the cooling insert 37 floated by the spring 38 is seated on the split mold main body 31 by the mold clamping force, and the cooling insert 37 and the split mold main body 31 are separated from each other by the core 5.
With 0, a continuous cavity 34 is formed.

Thereafter, molten resin is injected into the cavity 34 from the sprue 36 to mold the parison 70, the mold is opened, the parison 70 is transferred to the blowing step together with the core 50, and air pressure is applied to the parison 70 from the inside. Attach to a specified shape.

In this embodiment, since the gap 90 is formed between the cooling insert 37 and the split mold main body 31 when the mold is opened, heat is hardly transferred between the two and the two are kept at the set temperature. Can be maintained at extremely close temperatures. Therefore, in the parison 70 formed by the parison molding die 300, the portion formed by the cooling insert 37 is sufficiently cooled and solidified, and the split mold main body 31
Since the portion formed in (1) has a sufficiently low viscosity, the inner peripheral rib is not deformed during the blowing step, and the bellows of the boot can be sufficiently shaped.

In this embodiment, the floating device having the simplest structure consisting of the spring 38 and the headed pin 39 is shown. However, even if a hydraulic mechanism, a cam mechanism synchronized with the opening and closing of the mold is used, Similar effects are obtained.

Although the cooling insert 32 of this embodiment is fixed, the cooling insert 32 may have a floating structure.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a mold opening state of a parison molding die according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a sectional view showing the mold closed state of the embodiment.

FIG. 4 is an explanatory view of injection blow molding.

FIG. 5 is a cross-sectional view showing a closed state of a conventional parison molding die.

[Explanation of symbols]

 300 Parison Mold 30 Split Mold 31 Split Mold Main Body 32, 33, 37 Cooling Nest 38 Spring Constituting Floating Device 39 Headed Pin Constituting Floating Device 90 Gap

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B29C 49/64 2126-4F // B29L 22:00 4F

Claims (1)

[Claims] 1. A parison molding die used for injection blow molding and comprising a plurality of split molds, wherein the split mold comprises a split mold main body and a split mold main body for partially cooling the parison. A parison molding die comprising: a cooling insert arranged and a floating device for floating the cooling insert from the split mold main body and opening a gap between the two when the mold is opened.