JPH0446940A - Propylene resin molding having improved resistance to discoloration by exposure to radiation - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a propylene resin molded article in which the problem of discoloration due to radiation irradiation has been effectively solved.

(Prior Art) Propylene resins have excellent properties such as rigidity, impact strength, and transparency, and are widely used in medical instruments such as syringes, transfusion sets, and blood sampling instruments.

These molded medical devices are used after being subjected to sterilization treatment by radiation irradiation, but propylene-based resins have a problem in that their strength decreases due to radiation irradiation. Therefore, in order to prevent this decrease in strength, the medical device molded product is manufactured using a synthetic resin as a raw material mixed with a large amount of antioxidant.

(Problems to be Solved by the Invention) However, when an antioxidant is blended into a propylene-based resin, there is a problem in that the degree of discoloration (yellowing) increases after radiation irradiation, depending on the blending amount.

Therefore, an object of the present invention is to provide a propylene resin molded article in which the problem of discoloration due to radiation irradiation is effectively solved.

(Means for Achieving the Object) The propylene resin molded article of the present invention is formed from a resin composition in which a fatty acid amide compound is added to a propylene resin, and is subjected to radiation irradiation treatment. .

That is, the present invention has succeeded in effectively solving the problem of discoloration caused by radiation irradiation by using a fatty acid amide compound as a discoloration inhibitor.

(Preferred Embodiment of the Invention) (1) The propylene resin used in the present invention includes not only propylene homopolymers, but also propylene, ethylene, butene-1,4-methylpentene-1, etc. Examples include copolymers with α-olefins other than propylene, and the copolymers may be either random copolymers or block copolymers, and these may be used alone or in the form of a blend. I can do it. In particular, when manufacturing medical devices, it is recommended to use copolymers or blends with an ethylene content of 5% by weight or less, for example, from the viewpoint of fit with other parts (liquid leakage), productivity, etc. is desirable.

Also, the melt flow rate (MFR) of propylene resin
Although it depends on the type of molded product, -5 to 50
In the present invention, the syringe outer barrel preferably has an ethylene content of 3.5 to 5.0% by weight and an MFR of IO to 40%.
g / 10 m1n is suitable, and for the needle hub and protector, the ethylene content is O to 4.0% by weight, and the MFR is IO to 30 g /
10 m1n is suitable.

Amide, A In the present invention, the fatty acid amide compound used as a discoloration improver includes an amide compound of a saturated or unsaturated fatty acid having 18 to 38 carbon atoms, such as oleic acid amide, erucic acid amide, stearic acid amide, etc. I can list.

In particular, oleic acid amide is most preferred.

These fatty acid amide compounds can be used singly or in combination of two or more, and may be used in amounts ranging from 0 to 0.3 parts by weight, particularly from 0.03 to 0, per 100 parts by weight of the propylene resin. It is desirable to use it in a proportion of .20 parts by weight.

Since the molded product of the present invention is sterilized by radiation irradiation, in addition to the above-mentioned fatty acid amide-based compounds, antioxidants are added to prevent the strength of the propylene-based resin from decreasing. It is preferable to use As such antioxidants, those known per se can be used, and for example, tris(2,4-di-t-butylphenyl) phosphite and the like are preferably used. - It is preferable that the antioxidant is used in an amount of 0.05 to 0.50 parts by weight per 100 parts by weight of the propylene resin.
According to the present invention, even when such an antioxidant is used, the problem of discoloration due to radiation exposure can be effectively solved.

In addition to the above-mentioned additives, the present invention may also contain known additives such as light stabilizers, antistatic agents, nucleating agents, neutralizing agents, dispersants, pigments, etc., to the extent that the purpose of the present invention is not impaired. Various additives can be used.

Molding λ1 The molded product of the present invention is obtained by blending -fi with each of the above-mentioned additives in a propylene resin, and applying the mixture to a roll or a Banbury mixer.
It can be melted and kneaded in a mixing machine such as an extruder to form pellets, or it can be molded by injection molding without pelletizing.

The injection molded product is packaged with a suitable film, for example, and then subjected to sterilization treatment by radiation irradiation to produce a product. Gamma rays or XIJil are suitable as the radiation, and preferably cobalt-60 gamma rays are used. The amount of irradiated AI is preferably 5 Megarats or less, particularly 1 to 4 Megarats. Furthermore, radiation irradiation can be performed in a vacuum, in an inert gas such as nitrogen, or in the air.
It is desirable to carry out the process at a temperature of 0° C. or lower, particularly room temperature or lower.

(Example) Hereinafter, the present invention will be described in detail based on Examples.

Example 1.2 Comparative Example 1.2 Ethylene content 1.5% by weight, M F RlOg/lO*
in propylene-ethylene random copolymer powder 10
The additives shown in Table 1 were added to 0 parts by weight, mixed using a mixer, pelletized using a 60 mm diameter extruder, and molded into a 120 x 130 x 1 m thick sheet using an injection molding machine.

The sheet was directly irradiated with 2.5 Megarats of radiation using a Cobalt-60 source.

This sheet irradiated with radiation was placed in a gear oven at 60° C. and left for 10 days to accelerate discoloration (yellowing). The degree of discoloration was visually observed, and the color difference was measured using the sheet before radiation irradiation as a reference. The results are shown in Table 1.

Note that the criteria for visual observation are as follows.

0: Almost no discoloration.

O: Slightly discolored.

×: Obvious discoloration.

Table 1 In the above table, the amount of each additive is shown in parts by weight.

In addition, the following additives were used.

Antioxidant part 1 Tris (2,4-di-t-butylphenyl) book? Product name: Irgafuos 16δ hydrochloric acid absorbent; Calcium stearate, product manufactured by Sankyoki Gosei Co., Ltd. Nucleating agent 1; 1,3,2,4-di(p-methylbenzylidene)-sorbitol, product manufactured by Shinnihon Rika Co., Ltd. Name: Gelol MD discoloration improver; product manufactured by Oleylamide Lion Axie Co., Ltd. (Effects of the invention) According to the present invention, the problem of discoloration due to radiation exposure is effectively solved, and it is particularly useful as a medical device that is sterilized by radiation exposure. A propylene resin molded product is provided that is extremely suitable for the following uses.

Claims (3)

[Claims] (1) A molded article characterized in that it is molded from a resin composition in which a fatty acid amide compound is added to a propylene resin, and is subjected to radiation irradiation treatment. (2) The molded article according to claim 1, wherein the fatty acid amide compound is oleic acid amide. (3) The fatty acid amide compound is propylene resin 10
The molded article according to claim 1, wherein the molded article is added in a proportion of 0.01 to 0.30 parts by weight per 0 parts by weight.