JPS60125631A - Medical vessel - Google Patents

Abstract

PURPOSE:To improve the transparency and heat resistance of a medical vessel by applying injection stretch blow molding to a propylene-ethylene random copolymer whose melt flow index is 4-20g/10min and to which no nucleation agent is added. CONSTITUTION:A propylene-ethylene random copolymer whose melt flow index is 4-20g/10min and to which no nucleation agent is added is subjected to injection stretch blow molding, and thereby a medical vessel excellent in transparency and heat resistance is obtained. It is desirable that said propylene-ethylene random copolymer contains little ethylene, and in particular, the one containing ethylene of 0.5-8wt%, or more preferably of 1-6wt%, is preferable in terms of transparency and heat resistance. The injection stretch blow molding is executed in such a manner that, after a closed-end parison is molded by injection molding, a process of preliminary blowing and the adjustment of a stretching temperature are executed, and then stretch blowing is conducted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a medical container made of reprinted polypropylene having excellent transparency and heat resistance. More specifically, the present invention relates to a container suitable for infusions such as Ringer's solution and Hartmann's solution.

The standards for plastic containers for infusions are stipulated by the Japanese Pharmacy Law, and in particular, transparency is required to be as high as possible to allow observation of foreign substances in the liquid contents. Polypropylene resin is used for this infusion container because it has excellent mechanical properties, heat resistance during sterilization, and safety and hygiene. Transparency has been improved by molding, etc., but it is still insufficient.

As a result of intensive studies to improve the transparency of infusion containers made of polypropylene resin, the inventors of the present invention succeeded in creating a transparent container by performing injection stretch blow molding using a specific polypropylene resin. It was found that it was possible to obtain
We have arrived at the present invention.

That is, the present invention has a melt flow index of 4 to 20.
This medical container is characterized by being molded from a propylene-ethylene random copolymer having a molecular weight of 1i'710 minutes by an injection spread blow molding method without adding a nucleating agent.

The propylene-ethylene random copolymer used in the present invention is condition 14 of Japanese Industrial Standard JISK-7210.
Melt flow index (hereinafter referred to as M
(abbreviated as FI) is 4 to 20 f710 minutes. Midfielder
If I is less than 4171.0 minutes, the resulting container will have insufficient transparency, and if it exceeds 20 f/10 minutes, the thickness of the container will be significantly uneven.

In addition, in the present invention, the propylene-ethylene random copolymer preferably has a low ethylene content, and in particular, one with an ethylene content of 05 to 8% by weight, preferably 1 to 6% by weight, has good transparency and heat resistance. It can be suitably used from above.

Furthermore, transparency can be improved by using a nucleating agent, but
In this application, the transparency is so good that it is not necessary to use it.

The injection stretch blow molding method used in the present invention is a molding method in which a bottomed parison is molded by injection molding, and then a product is obtained by stretching and blowing after preliminary blowing and stretching temperature adjustment. A combination of mechanical warp stretching and air blowing methods is commonly used.

The molding machines used for this are injection stretch blow molding machines A'5B-50 and ASB-150 manufactured by Nissei ASB Machinery Co., Ltd.
.

Examples include ASB-250 and ASB-650.

Conditions for molding the medical container made of the propylene-ethylene random copolymer of the present invention, which is highly transparent and has less uneven thickness, are as follows:
For example, when using an injection stretch blow molding machine ASB-50, the following conditions are desirable.

Injection molding temperature: 200-260℃ Preliminary blowing: Warp stretch magnification 10-18 times Horizontal stretch magnification
12-20 times blowing pressure 3-6 to 9/cm Stretching temperature adjustment mold temperature = 90-140℃ Stretching blowing Fresh stretching ratio 12-65 times Lateral stretching ratio 12-60 times Blow pressure 4-20 Kg / cr1 The medical container of the present invention is made of the above-mentioned propylene-ethylene random copolymer (and, if necessary, a very small amount of additives such as stabilizers is added,
By the above injection stretch blow molding method, the wall thickness of the body is usually 0.2 mm.
~tomm.

Since the medical container of the present invention has excellent transparency and heat resistance, it can be sterilized at high temperature and can be suitably used as an infusion container.

The present invention will be explained below with reference to Examples.

Example 1 A propylene-ethylene random copolymer having an MFI of 151 i'/10 minutes and an ethylene content of 4 parts was processed using a Nisshin ASB machine (manufactured by Kiki, injection stretch blow molding machine ASB-5).
Injection stretch blow molding was carried out under the following conditions at 0 Cc to form a round bottle with a body diameter of 70 mm and a capacity of 500 Cc.

Injection stretch blow molding conditions Injection molding temperature: 220°C Injection mold temperature = 15°C Preliminary blowing: 1x vertically, 14x horizontally Preliminary blowing air pressure 5 Ky/cJ Stretching temperature control mold temperature: 100°C Stretching pro m : Vertical 18 times, horizontal 12 times stretching Blow pressure = 9 cm/cng The resulting bottle weighed 247 cm, had good wall thickness uniformity, and was a container with excellent transparency, especially when containing the liquid. It had good transparency and was suitable for medical containers such as infusion containers. The wall thickness of the body is 0.507n7n, and the haze of the cut test piece was measured using a Nippon Juishiki haze meter.
7 as measured by the method described in SK-6714
It was 8chi.

Example 2 In Example 1, the propylene-ethylene random copolymer had an MFI of 6 f/10 min and an ethylene content of 2.
Injection stretch blow molding was carried out in the same manner as in Example 1, except that a heavy propylene-ethylene random copolymer was used, and a round bottle with a capacity of 500 cc was molded. The obtained bottle weighs 24 f, has good wall thickness uniformity, and is a container with excellent transparency.It has particularly good transparency when filled with liquid, and is suitable as a medical container such as an infusion container. Met. The wall thickness of the body was 0.50 mm, and the degree of haze was 92 degrees.

Comparative Example 1 In Example 1, except that a propylene-ethylene random copolymer having an MFI of 2ii'710 minutes and an ethylene content of 2 folds was used as the propylene-ethylene random copolymer. In the same manner as above, injection stretch blow molding was performed to obtain a round bottle with a capacity of 500 cc.

The resulting bottle had insufficient transparency, with a body wall thickness of 0.4
9 mm, and the degree of haze was 198 degrees.

Comparative Example 2 In 11Ti Example 1, a propylene-ethylene random copolymer having an MFI of 251,710 minutes and an ethylene content of 20% was used as the propylene-ethylene random copolymer, but in the same manner as in Example 1. Although injection stretch blow molding was carried out, the resulting bottle had a large uneven thickness in both the vertical and horizontal directions, making it unusable.

patent applicant Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] A medical container characterized by being molded by injection stretch blow molding of a propylene-ethylene random copolymer having a melt flow index of 4 to 2 of/1° without adding a nucleating agent.