JPS592818A - Orientation blow molding method - Google Patents

Abstract

PURPOSE:To make it possible to reduce the wall thickness of the neck of a hollow molded article, such as a bottle or the like, by previously blow-molding the neck of an injection-molded parison with bottom using a split die while regulating the temperature, and then moving the parison to an orientation blowing mold to form a body. CONSTITUTION:An injection-molded bottled parison 4 is housed in a temperature- regulating pot 2. Split die halves 3, 3 are closed, and air is blown thereinto to mold a neck 4a of the parison 4. Then, the parison 4 is moved to a blowing mold 10. While the molded neck 4a is airtightly maintained, an orientation rod 13 is inserted into the blowing mold 10, and air is blown thereinto to form a main body part of a hollow molded article.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stretch blow molding method used for producing hollow molded products such as bottles made of synthetic resin.

In a hollow molded product such as a bottle formed by stretch blow molding an injection molded parison with a bottom, the neck portion is thicker than the main body portion formed by stretch blow molding. Especially around the neck 7
It is difficult to mold the neck part of a product with a lunge into a thinner wall due to molding problems.

This invention aims to eliminate the disadvantages of hollow molded products when molded using injection molded parisons by molding the neck of an injection molded bottomed parison to any thickness as required. be.

Another object of the present invention is to provide a new method in which the neck of the parison can be thinned by blow molding during temperature control of the parison, and the neck can also be molded into a predetermined shape.

The present invention will be explained in detail below using illustrated examples.

In the figure, 1 is a neck type, 2 is a temperature control pot), 3.3 is a split type provided at the open end of the temperature control pot 2 so as to be openable and closable, and 4 is a bottomed parison.

The neck type 1 has a transfer plate 5 which rotates intermittently under the substrate.
The temperature control pot 2 is attached to the bottom of the neck mold 1 so that it can be opened and closed freely.
Place it on the holder.

This temperature control pot 2 consists of a cylindrical body with an open top,
The parison accommodating portion 2a is formed to be slightly larger than the parison 4, and has a passage 7 for a heat medium or a coolant in the wall portion.

The split molds 3, 3 have a cavity 8 on the bartending line that airtightly surrounds the neck 4a of the parison 4.

Reference numeral 9 denotes a blowing core, which is not shown but is attached to a lifting device installed on the board, and is inserted into the neck mold 1 through the board and the transfer board 5 when the transfer board 5 is stopped.

Further, the tip 9a of the blowing core 9 is formed to have approximately the same diameter as the diameter of the parison, and when the parison 4 is positioned inside the temperature control pot 2, air at a predetermined pressure is blown into the parison.

Reference numeral 10 denotes a blow mold, which has a recess 12 for housing the parison neck 4a blow-molded in the upper part of the cavity 11, and inserts the parison 4 in the center of the cavity from above the substrate through the transfer plate 5 and the neck mold 2 into the parison. A predetermined hollow molded product can be formed by a stretching rod 13 and a blowing core 14 inserted into the hollow molded product.

Next, the method of the present invention will be explained in detail using the above apparatus.

First, the parison 4 is injection molded using the neck mold 1 as usual. At this time, only the threaded portion is molded with the neck mold 1, and the neck portion 4a is molded with an injection mold.

Next, the parison 4 is transferred to the IT temperature control position held in the neck mold 1. In this temperature control position, as shown in FIG. 1, when the neck mold 1 stops, the temperature control device is raised to accommodate the parison 4 in the temperature control pot 2. When the parison 4 reaches its home position, the split molds 3, 3 are closed and the neck 4a of the parison 4 is surrounded by the cavity 8. In addition, split molds 3 and 3 are closed! The parison 4 may be placed in the pot until the end. Next, the blowing core 9 is inserted into the neck mold, the tip 9a is placed inside the parison, and air is blown into the parison. The parison 2, which is in a softened state due to this air blowing, expands completely inside the temperature control pot 2 and into the split molds 3, 3, as shown in FIG. Contact. At the same time, the neck portion 4a is also expanded in the cavity 8, and blow molding is performed there.

When the shaping of the neck 4a and the adjustment of the parinon temperature are completed, as shown in FIG. 3, the split mold 3° is first opened, and then the temperature control pot 2 is lowered. At this time, the blowing core 9 is also raised to its original position and extracted from the parison 4. Since the parison 4 is again held in the neck mold 1, it is transferred together with the neck mold to the stretch blow molding position by the transfer plate 5.

At the stretch blow molding position, as shown in FIG.
When the blowing die 10 stops at a fixed position, the blow mold 10 closes and the molded neck 4a is held airtight in the accommodation recess 12. A stretching rod 13 that has descended from above together with a blowing core 14 is inserted into the parison, and by stretching the stretching rod 13 and blowing compressed air from the blowing core 14, the main body is formed, that is, a hollow molded product is formed. Biaxial orientation molding is mainly performed below the neck 4a, which becomes the body. After molding, the above blow mold I
The mold C is opened in the same way as in the normal case, and the blown core etc. are pulled back to their original positions.

As described above, in this invention, the neck part of the parison is molded completely separately from the main body part.
The neck can be blow molded in any way, and the neck wall thickness can also be reduced by blow molding. Moreover, since the neck is formed when the temperature of the parison is adjusted, there is no change in the processes of parison molding, temperature control, and stretch blow molding, and there is no change in the molding cycle, so the split mold for neck molding is placed in the temperature control member. It has the advantage that it can be immediately applied to the conventional stretch blow molding method just by installing it.

[Brief explanation of the drawing]

The drawings illustrate the stretch blow molding method according to the present invention; FIG. 1 is a longitudinal cross-sectional view of the temperature control device during insertion of the parison, FIG. 2 is a longitudinal cross-sectional view of the temperature control device during molding of the neck of the parison, and FIG. 3
The figure is a longitudinal sectional view of the temperature control device when the parison is removed, and FIG. 4 is a longitudinal sectional view of the blow mold when the parison is accommodated. 1... Neck type, 2...
Temperature control pot, 3... Split mold for neck molding, 4.
...Bottomed parison, 4a... Neck of parison, 8... Cavity for neck molding, 10...
...Blowing mold, 11... Capity, 12...
...accommodating recess in the neck, 13...extension rod. Figure 2

Claims (1)

[Claims] In the method of controlling the temperature of an injection molded parison with a bottom and then stretch blow molding it into a hollow molded product such as a bottle in a blow mold, the neck of the parison with a bottom is cut using a split mold during the temperature control. A stretch blow molding method characterized by blow molding.