JPH0611823B2 - Polypropylene resin material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a polypropylene resin material, and more specifically, a medical device, a food packaging material using a polypropylene resin composition having characteristics such that it does not easily deteriorate even when irradiated with radioactive rays. Radiation resistant polypropylene resin materials such as

When used as a medical instrument, a food packaging material, etc., a polypropylene molded article may be irradiated with radiation such as γ-rays for the purpose of sterilization. At that time, the molded product itself is deteriorated by radiation, the tensile elongation of the molded product is remarkably reduced, and becomes extremely brittle.
There were problems such as yellowing and the occurrence of cracks, and there were practical problems.

As a method for preventing the deterioration of the polyolefin due to radiation irradiation, JP-A-55-19199 and JP-A-58-426 are known.
No. 38, JP-A-58-49737 and the like, a method of adding a hindered amine compound or a phenol compound to a resin is known.

2.5-3.0 Mrad for normal polypropylene composition
Irradiation with cobalt 60 causes progress of deterioration, and elongation after irradiation remarkably decreases. The addition of the radiation resistance by the above-mentioned additives, however, has not yet been sufficiently effective, and the commercial value of the molded product is often impaired by the coloring of the additives.

The present inventors have reached the present invention as a result of research in view of the above circumstances, and the present invention is based on 100 parts by weight of polypropylene or propylene-ethylene copolymer, and diallyl (iso) phthalate. A radiation-resistant polypropylene resin material characterized by using a polypropylene resin composition containing 0.05 to 2 parts by weight.

The propylene-ethylene copolymer used in the present invention includes a random copolymer and a block copolymer, and when used in an application requiring resistance to radiation, a random copolymer is used. Is preferred. The melting index of these resins (MFR, JIS K 6758, load 2.
16 kg, temperature 230 ° C. same as below. ) Is not particularly limited, and the preferable range varies depending on the molding method, but in the case of injection molding, MFR = 1 to 50.

When the composition of the present invention is irradiated with radiation, the change in MFR is very small, and it is possible to prevent deterioration and yellowing of molded articles using this composition.

The amount of diallyl isophthalate (DAiP) and / or diallyl phthalate (DAP) is 0.01 to 2 parts by weight, preferably 0.05 to 1 part by weight, based on 100 parts by weight of the resin. If the amount is less than 0.01 parts by weight, the effect is poor and the resin is deteriorated to lower the tensile elongation. If the amount exceeds 2 parts by weight, the tensile elongation tends to be decreased.

In the composition of the present invention, in order to impart cold resistance, polypropylene is blended with ethylene-propylene rubber or the like,
Or, in order to impart transparency, sodium benzoate,
Clarifying agents such as dibenzylidene sorbitol, bis (P-methylbenzylidene) sorbitol, nucleating agents are added, or other antioxidants, UV absorbers, lubricants, antistatic agents, anti-blocking agents, splitting agents are added depending on other purposes. Agents, neutralizing agents and the like can be added.

The composition of the present invention may be molded into any shape,
Generally, powdered polypropylene or ethylene-
A diallyl (iso) phthalate and, if necessary, various blends or additives described above are added to the propylene copolymer,
After mixing appropriately, the mixture is melt-kneaded by an extruder to form pellets, and the pellets are formed into a molded product by injection molding or the like.

Next, the present invention will be described more specifically with reference to Examples and Comparative Examples.

Examples 1-5, Comparative Example 1 Diallyl isophthalate and / or diallyl phthalate as described in Table 1 was added to 100 parts by weight of Polymer I, which is a pellet having the following composition, and 40 mm after mixing.
It was extruded with a φ extruder at 220 ° C. and pelletized. These pellets were used in a 10 ounce injection molding machine at an injection temperature of 230 ° C., an injection pressure of 750 kg / cm ² and a thickness of 2 mm, 1
A flat plate of 0 cm × 12 cm was obtained. This was evaluated by irradiating 3.0 Mrad of gamma rays with a cobalt 60 radiation source. The results are shown in Table 1.

Polymer I (1) Propylene-ethylene random copolymer Ethylene content 1.8 wt% MFI 18 g / 10 min (2) Tetrakis [methylene (3,5-di-t-butyl-
4-hydroxyphenyl) propionate] methane
0.05% by weight (3) Calcium stearate 0.05% by weight From the above results, materials using this composition, that is, syringes that require sterilization or disinfection by irradiation, clips, medical instruments such as surgical threads, food containers, food packaging materials such as films, or irradiation. Polypropylene resin materials such as plastic drums, fasteners, and other nuclear-related materials, which receive the radiation, do not deteriorate in physical properties, particularly the tensile elongation does not decrease, and are extremely useful.

Claims (1)

[Claims] 1. A radiation-resistant polypropylene characterized by using a polypropylene resin composition in which 0.05 to 2 parts by weight of diallyl (iso) phthalate is mixed with 100 parts by weight of polypropylene or a propylene-ethylene copolymer. Resin material.