JPS6111263B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to a resin composition with improved radiation resistance. Electrical wires, cables, and various equipment used in nuclear reactors, breeder reactors, or ionizing radiation generators are often constantly exposed to considerable amounts of radiation. Therefore, resin compositions used for such purposes as coating insulating materials for electric wires and cables, insulating materials for various types of equipment, packing, sealing materials, frames, hose materials, etc. are required to be highly rated from an economic and safety standpoint. It is required to have radiation resistance of . In order to meet this demand, the inventors proposed a method for producing a resin composition containing acenaphthylene or a functional derivative thereof with excellent radiation resistance, and were able to achieve great results. Furthermore, as a result of intensive studies regarding the improvement of radiation resistance, the inventors found that acenaphthylene or its functional derivatives (including halogenated acenaphthylene), or a substance selected from the group such as halogenated indene, Discovered that it is effective to use an appropriate amount of a hydroperoxide polymerization initiator and an organic peroxide together as a free radical generator for polymerizing the substances in a blended resin composition, and completed this invention. That's what I did. That is, in this invention, for 100 parts by weight of a base polymer such as a thermoplastic resin or rubber, the general formula: Acenaphthylene or its functional derivative represented by (wherein R is an alkyl group having 1 to 4 carbon atoms, chlorine or bromine, and m is an integer of 0 to 6), or the general formula At least 0.5 parts by weight of one or more substances selected from the group of halogenated indenes represented by the formula (wherein X is chlorine or bromine, and n is an integer from 2 to 7); 0.2 to 10 parts by weight of hydroperoxide polymerization initiator and 0.5 to 10 parts by weight of organic peroxide
10 parts by weight of the radiation-resistant resin composition. The reason why the composition according to the present invention can exhibit the excellent radiation resistance as described above is not necessarily clear, but the reason why the composition according to the present invention can exhibit the excellent radiation resistance as described above is that the hydroperoxide-based polymerization initiator used as a free radical generator The presence of acenaphthylene compounded in the composition,
It is believed that this method significantly accelerates the polymerization of the compound or its functional derivatives or halogenated indenes, and moderately adjusts the crosslinking of the base polymer, resulting in good results. Furthermore, it has also been revealed that flame retardancy is improved in the case of halogenated acenaphthylene and halogenated indene. Examples of thermoplastic resins and rubbers used as the base polymer in this invention include polyethylene, polypropylene, polybutene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-propylene copolymer, ethylene-
Propylene-diene copolymer, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate-grafted vinyl chloride copolymer, ethylene-ethyl acrylate-grafted vinyl chloride copolymer, ethylene-vinyl chloride copolymer,
Propylene-grafted vinyl chloride copolymer, chlorinated polyethylene, chlorinated polyethylene-grafted vinyl chloride copolymer, polyurethane, polyamide, polyester, acrylic resin, butyl rubber,
Chloroprene rubber, nitrile rubber, natural rubber, silicone rubber, chlorosulfonated polyethylene,
Examples include styrene-butadiene rubber, styrene-butadiene-acrylonitrile copolymer, acrylonitrile-styrene copolymer, and polyester-ether elastomer. In addition, acenaphthylene and its functional derivatives represented by the above general formula include 5,6-dimethylacenaphthylene, 3,5,6,8-tetramethylacenaphthylene, 5,6-diethylacenaphthylene,
3,5,6,8-tetraethylacenaphthylene,
3,5-dipropylacenaphthylene, 3,5-
6,8-tetrapropylacenaphthylene, 3,5
-dibutylacenaphthylene, 3,5,6,8-tetrabutylacenaphthylene, 3,5-dibromoacenaphthylene, 3,5,6,8-tetrabromoacenaphthylene, 3,5-dichloroacena Phthylene, 3,5,6,8-tetrachloroacenaphthylene, 3,4,5,6,7,8-hexabromoacenaphthylene, 3,4,5,6,7,8-hexachloroacena phthylene, etc. Furthermore, as the halogenated indene represented by the above general formula, 4.
5,7-tribromoindene, 4,5,7-trichloroindene, 1,3,4,5,7-pentabromoindene, 1,3,4,5,7-pentachloroindene, 1,3,4 -5,6,7-heptachloroindene, etc., and in the present invention, one or more of these substances are selected and blended. In order to exhibit the effects of the present invention, the blending amount must be at least 0.5 parts by weight based on 100 parts by weight of the base polymer made of the above-mentioned resin or rubber. Next, examples of the hydroperoxide polymerization initiator used in the present invention include t-butyl hydroperoxide, di-isopropylbenzene hydroperoxide, and cumene hydroperoxide. The reason why the amount is limited to 0.2 to 10 parts by weight per 100 parts by weight is that below the lower limit, the effect of this invention will be insufficient, and even if the upper limit is exceeded, the effect of increasing the amount will hardly be seen. be. Further, as the organic peroxide used in this invention, dicumyl peroxide, 1,3-bis(t
-butylperoxyisopropyl)benzene,
Examples include 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, t-butylcumyl peroxide, etc., and the blending amounts are the same.
The reason why it is limited to 0.5 to 10 parts by weight is that below the lower limit, the crosslinking effect of the base polymer will be insufficient.
Moreover, even if the upper limit is exceeded, the effect of increasing the amount is hardly seen. Depending on the purpose of use, the composition of the present invention may be added with suitable reinforcing agents, fillers, pigments, lubricants, vulcanizing agents, crosslinking aids, or heat or light stabilizers to reduce its properties. There is no problem in adding an appropriate amount as long as it does not cause any damage. As is clear from the examples below, the composition of the present invention can significantly improve its radiation resistance, and its industrial value is extremely large. The present invention will be specifically explained below with reference to Examples. Examples 1 to 6 and Comparative Examples 1 to 4 The compositions shown in Table 1 were added to the ethylene propylene copolymer according to the compositions shown in Table 1, and the mixture was thoroughly kneaded with a heating roll and heated at 160°C. Press molding was performed for 30 minutes to obtain sheets with a thickness of 1 mm and 3 mm. The properties of the obtained sheet and the properties after irradiation with γ-rays of 100 Mrad are shown in the same table.

[Table] Examples 7 to 10 and Comparative Examples 5 to 6 The compositions shown in Table 2 were well kneaded with a heated roll and press-molded at 170°C for 30 minutes to obtain a 1 mm thick sheet. The properties of the obtained sheet and the properties after this sheet was further irradiated with 100 Mrad of gamma rays are shown in the same table.

[Table] Examples 11 to 13 and Comparative Examples 7 to 8 The compositions shown in Table 3 were thoroughly kneaded with a heating roll and press-molded at 160°C for 30 minutes to obtain a 1 mm thick sheet. The properties of the obtained sheet and the properties after this sheet was further irradiated with 100 Mrad of gamma rays are shown in the same table.

【table】

[Table] According to the results in the table above, the following is clear.
That is, compared to a composition containing dicumyl peroxide alone, the combined use of t-butyl hydroperoxide resulted in better initial properties and better results after radiation irradiation, and acenaphthylene or its functional derivatives, halogenated indene, etc. The radiation resistance function can be more effectively exhibited.

Claims (1)

[Claims] 1. Base polymer such as thermoplastic resin or rubber
For 100 parts by weight, general formula (wherein R is an alkyl group having 1 to 4 carbon atoms, chlorine or bromine, and m is an integer of 0 to 6) or a functional derivative thereof,
or general formula At least 0.5 parts by weight of one or more substances selected from the group of halogenated indenes represented by the formula (wherein X is chlorine or bromine, and n is an integer from 2 to 7); 0.2 to 10 parts by weight of hydroperoxide polymerization initiator and 0.5 to 10 parts by weight of organic peroxide
A radiation-resistant resin composition characterized in that it contains 10 parts by weight of a radiation-resistant resin composition.