JPS5995121A - Treatment of primary molded product for biaxially orientation type bottle - Google Patents

Abstract

PURPOSE:To reduce scratches while treating the titled primary molded product remarkably by a method wherein the primary molded product is preliminarily quenched immediately after injection molding. CONSTITUTION:A primary molded product is quenched after the gate cutting immediately after injection molding. The extent of the quenching is recommended such that the temperature of the primary molded product when it is gate cut after injection molding may be quenched down to 0 deg.C within around 2min. Through these procedures, any scratches of the primary molded product while treatment may be reduced remarkably because the spherulite of the crystal on the surface of the primary molded product is small increasing the density thereof as well as the crystallinity index on the surface of the primary molded product.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to polyethylene terephthalate tit 11
This relates to a method for handling a primary molded product for W22-axis stretch blow-molded bottle molding, and more specifically, it relates to a method for handling a primary molded product for forming a W22-axis stretch blow-molded bottle. The object is to extremely reduce the occurrence of spots, scratches, etc. on the surface of the molded gutter body during biaxial stretch blow molding.

Recently, biaxially stretched tV made of polyethylene terephthalate resin (hereinafter referred to as PET) has been used due to its advantages in terms of content resistance, mechanical strength, optical appearance, and incineration treatment.
Bottles are now being used in large quantities.

This PET biaxial stretch blow molded bottle and trough body BIT is biaxially stretch blow molded in order to take full advantage of its excellent characteristics.For this purpose, a primary molded product in the shape of a cylinder with a bottom is first formed by injection molding. However, a molding method is used in which this injection-molded primary molded product is biaxially stretched and blow molded into a gutter body.

In this way, an injection molding machine and a biaxial stretch blow molding machine are required to mold the gutter body of a PIGT bottle. It would be uneconomical to install the cedar equipment as both equipment are extremely expensive.

Similarly, it is uneconomical to transport a very small gutter body of XkJA to a long distance due to its large volume.

In addition, if the molding speed of the primary molded product by the injection molding device is much higher than the molding speed of the gutter body by the biaxial stretch blow molding device, the injection molding device and the biaxial stretch blow molding device may Combining them in a ratio of 1 to 1 will significantly reduce the operating rate of the injection molding equipment, and is also extremely uneconomical.

For this reason, primary molded products are intensively injection molded at a factory located in an appropriate location, and this injection molded primary molded product with a small volume is transported by truck or the like to a factory located near the consumption area where it is placed on a biaxial stretching protrusion. A widely used method is to mold it into a gutter body.

However, according to the above-mentioned operation method, the primary molded product is first transported by a belt conveyor, etc., and then dropped and supplied into a storage container such as a cardboard box, and then stored. Primary molded products are often transported by trucks, etc. over long periods of time, and storage containers are often stacked on top of each other during storage and transportation. As a result of being bumped into or pressed against, spots and scratches occur on the surface of the product, and the scratches formed on the surface of the primary molded product are directly stretched onto the surface of the product, the gutter body. A serious problem has arisen in which the situation is exposed.

In particular, since the PET bottle and gutter body have excellent transparency,
The above-mentioned scratches appearing on the gutter body as a product become extremely noticeable.

The present invention was devised to solve the problems in the conventional example described above, and will be explained below.

The handling method of the primary molded product according to the present invention includes transporting, storing, transporting, etc. When handling, the primary molded product is previously subjected to a rapid cooling treatment immediately after injection molding.

The period of rapid cooling for the primary molded product is not particularly limited, but when the primary molded products that have just been injection molded are transported out of the injection molding machine, they may collide with each other and cause damage. Therefore, it is best to perform this after the gate cutting operation immediately after injection molding.

This means that each piece is cut in large numbers at the time of gate cutting.
Since the next molded products are still individually and independently held, by performing the quenching treatment while they are individually held, each primary molded product will come into contact with completely other products. This is because the quenching process can be performed before the quenching process occurs.

In addition, as for the degree of rapid cooling, the temperature of the primary molded product at the time of injection molding and gate cutting is approximately 56 to 60℃.
℃], but this temperature can be reduced to 0 [℃] within about 2 minutes.
It is desirable that the level is as follows.

The reason why the time required for cooling is set to within about 2 minutes is because dry ice, which is inexpensive, can be used as a cooling material, and the cooling operation becomes easy.

Of course, using liquid nitrogen, etc., the temperature can be reduced to 0 [℃] in about 10 seconds.
] Although it is possible to cool down to a temperature below this, there is no significant difference in the effects of the present invention.

As mentioned above, the gist of the present invention is to perform a rapid cooling treatment on a primary molded product immediately after injection molding. In contrast, if 295 slowly cooled primary molded products are stored in a cardboard box containing 9,000 pieces and placed on a truck, approximately 12
When inspected after being transported for 00 km, 63.6% of the vehicles had large spots and 61.6% had scratches.
However, in contrast, when the method of the present invention was applied, under the same conditions, 21% had large spots and 420% had scratches.
It has been demonstrated that this can be significantly reduced.

The above experiment was conducted under extremely bad conditions, and in reality, 9,000 bottles were stored in a cardboard box in a line with no gaps, so it is unlikely that the occurrence of the scratches would be further reduced. it is obvious.

Now, as mentioned above, the method of the present invention has a clear effect of significantly reducing the occurrence of scratches during handling of the primary molded product, but why is it possible to reduce the occurrence of scratches? The technical reason why this is possible is still not clear.

This is because the surface of a primary molded product certainly exhibits great hardness when it is in a cooled state, but even if it is rapidly cooled, during handling operations such as transportation, storage, and transportation, This is because the temperature is the same as that of the one that was slowly cooled, that is, the ambient temperature, and there is no difference in surface hardness.

However, one possible reason for this significant reduction in the occurrence of scratches is that rapid cooling reduces the size of the crystal spherulites on the surface of the primary molded product, increasing its density. It is conceivable that the crystallinity of the surface portion of the molded product increases.

As is clear from the above description, the present invention can significantly reduce the occurrence of scratches on the surface of the primary molded product due to handling operations, thereby making it possible to obtain carriers of better quality as commercial products. Since it is only necessary to rapidly cool the primary molded product immediately after injection molding, the work is extremely simple, and the process of the present invention can be carried out in a short time, and has many other advantages.

Claims (1)

[Claims] Transporting, storing, and transporting primary molded products to be injection molded for biaxially stretched blow-molded bottles made of polyethylene terephthalate resin.
A method for handling a primary molded product for use in biaxially stretched bottle molding, in which the primary molded product is previously subjected to a quenching treatment immediately after injection molding when being transported and handled.