JPH0593101A - Radiation resistant elastomer composition - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an elastomer composition having high radiation resistance. [Structure] A repeating unit represented by the following formula (I):
It is assumed that 3 to 50 parts by weight of the benzophenone compound represented by the formula (III) is added to 100 parts by weight of the ethylene / acrylic elastomer composed of the repeating unit represented by the formula (II) and the crosslinking site. [Chemical 8] [Chemical 9] [Chemical 10]

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation resistant elastomer composition which is used as a jacket for electric wires and cables (hereinafter simply referred to as "cable").

[0002]

2. Description of the Related Art A cable used in a radiation environment such as a nuclear power plant is required to have radiation resistance.
In particular, the control cables for manipulator operations for handling nuclear fuel and maintaining the core are exposed to extremely high radiation, and therefore higher radiation resistance is required.

This radiation resistance is mainly borne by an outer sheath (sheath), and as a polymer material for the outer sheath of this type of cable, conventionally, polyetheretherketone has been disclosed in Japanese Utility Model Publication No. 60-84024. (Hereinafter referred to as PEEK) is well known. However, this PEEK is expensive and has a problem of poor workability. In addition,
Elasticity is also required as a cable material.

Therefore, it is an object of the present invention to provide a radiation resistant elastomer composition which has high radiation resistance, is inexpensive, and has excellent processability and elasticity.

[0005]

In order to solve the above problems, the present invention comprises a repeating unit represented by the following formula (I), a repeating unit represented by the formula (II) and a crosslinking site. 3 to 50 parts by weight of the benzophenone compound represented by the formula (III) was added to 100 parts by weight of the ethylene / acrylic elastomer.

[0006]

[Chemical 4]

[0007]

[Chemical 5]

[0008]

[Chemical 6]

When the amount of the above-mentioned benzophenone compound is less than the above range, the elongation is lowered and the resin is cured by receiving radiation. On the other hand, if it exceeds the above range, bloom (deposition on the surface) occurs, which is not preferable in appearance.

The above ethylene-acrylic elastomer is
Baymac B whose cross-linking site structure is shown below
124 (trade name of DuPont), and the formula (III
Examples of the benzophenone-based compound represented by the formula) are: Sumisosorb 130 in which R is C ₈ H ₁₇ in the formula;
H ₃ Sumisorb 110 (each of which is a product name of Sumitomo Chemical Co., Ltd.) can be used.

[0011]

[Chemical 7]

[0012]

The elastomer composition according to the present invention thus constructed has the required elasticity, and the radiation resistance is improved by adding the required amount of the benzophenone compound.

[0013]

[Examples] Examples 1 to 1 with the compounding ratio (parts by weight) shown in Table 1
4 and Comparative Examples 1 to 3 were kneaded and prepared. The kneading preparation is as follows:
Test roll of 120 ° C, 20
After kneading for 10 minutes, the temperature was lowered to 50 ° C. as a second kneading, and a crosslinking agent was added and kneading was performed for 10 minutes.

The thus-obtained elastomer composition was placed in a metal frame having a thickness of 1 mm and an inner dimension of 150 mm length × 150 mm width, and was press-crosslinked at 150 kgf / cm ² × 170 ° C. × 15 minutes, followed by pressure cooling. , Thickness 1mm x length 150mm x width 15
A 0 mm test sheet was obtained.

Looking at the finished appearance of this sheet (presence or absence of bloom), the elongation (El) at each γ-ray irradiation dose (using ⁶⁰ Co as a radiation source and a dose rate of 0.8 MR / hr. In the atmosphere at room temperature) and The results of measuring the tensile strength (Ts) are shown in the lower column of Table 1. In the table, the units of El and Ts are% and kg /
a mm ^2, circle and double circle good, × is bad, the blank represents the unmeasurable, "original" is of γ-ray-free illumination. Tensile speed is 20 according to JISK6301
It was performed at 0 mm / min.

[0016]

[Table 1]

From the results of this test, it can be understood that the elastomer composition according to the present invention is excellent in finishability and radiation resistance without generation of bloom at the specific blending ratio. Therefore, it can be sufficiently satisfied as an insulation coating for radiation-resistant electric wires and cables.

[0018]

Since the present invention is configured as described above, the radiation resistance is improved without suppressing the generation of bloom and causing the deterioration of the finishability.

Claims (1)

[Claims] 1. A benzophenone compound represented by the formula (III) is added to 100 parts by weight of an ethylene / acrylic elastomer comprising a repeating unit represented by the following formula (I), a repeating unit represented by the formula (II) and a crosslinking site. A radiation resistant elastomer composition containing 3 to 50 parts by weight. [Chemical 1] [Chemical 2] [Chemical 3]