JPH04268351A - Radiation-resistant composition containing chlorine - Google Patents

Abstract

PURPOSE:To produce the title compsn. which undergoes little degradation in physical properties even if irradiated with a high-dose radiation and is excellent in tensile properties, heat resistance, processability, etc. CONSTITUTION:The title compsn. is obtained by mixing 100 pts.wt. polymer component comprising 95-50wt.% chlorosulfonated polyethylene contg. 20-30% chlorine and 5-50wt.% epichlorohydrin or copolymer thereof with ethylene oxide, 3-100 pts.wt. acid acceptor, 10-80 pts.wt. process oil, and 3-15 pts.wt. antioxidant, and cross-linking the resulting mixture. The compsn. is useful as the material of a cable to be used in controlled areas of a high-dose radiation, such as a uranium concentration facility, a radioactive-waste treatment facility, and a reprocessing facility of spent fuel.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation-resistant composition that has excellent radiation resistance and good tensile properties, heat resistance, processability, etc.

0002

[Prior Art/Problems to be Solved by the Invention] In uranium enrichment facilities, radioactive waste processing facilities, spent fuel reprocessing facilities, etc., large amounts of radioactive materials must be chemically treated. Compared to nuclear power plants, there are many controlled areas with high radiation doses. Various materials used in such controlled areas are required to have radiation resistance. For example, cable materials are required to withstand doses of 800 to 1000 Mrad. However, there were almost no organic materials that could withstand such intense radiation. Therefore, the present inventors aimed to develop an organic material composition that is excellent in radiation resistance and has good tensile properties, heat resistance, processability, etc.

0003

[Means for Solving the Problems] In order to achieve the above object, the inventors of the present invention have conducted intensive research and have developed chlorosulfonated polyethylene (hereinafter referred to as "CSM") having a specific chlorine content. ),
A composition containing an acid acceptor, a process oil and an anti-aging agent, a polymer containing a specific composition ratio of CSM, epichlorohydrin or a copolymer of epichlorohydrin and ethylene oxide, an acid acceptor, a process oil and an anti-aging agent. It was discovered that a composition containing an inhibitor has excellent radiation resistance and good tensile properties, heat resistance, processability, etc., and the present invention was completed.

The first invention is a radiation-resistant composition comprising CSM having a chlorine content of 30% or less, an acid acceptor, a process oil, and an antiaging agent. The second invention consists of CSM (component A) epichlorohydrin or a copolymer of epichlorohydrin and ethylene oxide (component B),
This is a radiation-resistant composition comprising a polymer, an acid acceptor, a process oil, and an antiaging agent in a weight ratio of component/B component of 95/5 to 50/50.

The CSM used in the first invention is not particularly limited as long as it has a chlorine content of 30% or less and is of a clade that can be extruded with an appropriate formulation. The reason why the chlorine content is limited to 30% or less is that if the chlorine content of CSM exceeds 30, the radiation resistance will be poor. Note that if the chlorine content is less than 20%, it is difficult for CSM to exist as a polymer, so it is preferable that the chlorine content is 20% or more.

CSMs with a chlorine content of 30% or less include Hypalon 45 (chlorine content, 24%), Hypalon 20 (chlorine content, 29%) [all manufactured by DuPont],
TS-320 (chlorine content, 25%), TS-220 (
Chlorine content, 29%) [both manufactured by Tosoh], Denka C
Preferred examples include SM230 (chlorine content, 24%) [manufactured by Denki Kagaku]. In addition, for CSM with a chlorine content of 30% or less, if the amount is less than half, ethylene-propylene bum (either EPM or EPDM may be used), polyα
- Polymers blended with olefins (polyethylene, polypropylene, polyisoprene, etc.), chlorinated polyethylene with a chlorine content of 30% or less [ELASLENE 301A (chlorine content, 30%), manufactured by Showa Denko] can be used.

[0007] Furthermore, in the second invention, A component/B component
The weight ratio of the components is specified to be 95/5 to 50/50.The reason is that if the A component exceeds 95 (B component is less than 5), the radiation resistance will be poor; This is because if the number of components exceeds 50), the viscosity of the polymer becomes high and processability becomes poor. The chlorine content of component A is 20~
40%, especially 24-35% is preferred. In addition to CSM exemplified in the first invention, Hypalon 40 (chlorine content, 35%) [manufactured by DuPont] is exemplified as a suitable component A.

[0008] As epichlorohydrin and a copolymer of epichlorohydrin and ethylene oxide, those having a Mooney viscosity of 35 to 120-ML1+4 (100°C) and a specific gravity of 1.25 to 1.40 are preferably used. For example, epichlorohydrin [Epichromer H, manufactured by Osaka Soda, Zekron 1000, manufactured by Nippon Zeon], epichlorohydrin-ethylene oxide copolymer [Epichromer C,
Osaka Soda Co., Ltd., Zekron 2000, and Nippon Zeon Co., Ltd.] are exemplified.

In the first and second inventions, the acid acceptor is not particularly limited as long as it acts as a dehydrochlorination scavenger for halogenated polymers, such as lead monoxide, dibasic lead phthalate, etc. , hydrotalcite [Mg
6Al2(OH)16CO3.4H2O], etc., and these may be used alone or in combination. In the first invention, the acid acceptor has a chlorine content of 30%.
For the following parts by weight of CSM100, and in the second invention, 100 parts by weight of the polymer consisting of component A and component B.
It is desirable to mix 3 to 100 parts by weight of each of these parts by weight. The reason for this is that if it is less than 3 parts by weight, the acid-receiving effect tends to be low, and radiation resistance and heat resistance are not necessarily sufficient. This is because they tend to be inferior.

The process oil may be one commonly used for rubber, with aromatic and naphthenic oils being particularly preferred. For example, naphthenic oils include Koumolex No. 2 process oil (manufactured by Nippon Oil Co., Ltd.) and Sansen 4240 (manufactured by Nippon Sun Oil Co., Ltd.), and aromatic oils include Diana Process Oil A
H-58 [manufactured by Idemitsu Kosan], Alomar 790 [manufactured by Nippon Sun Oil], Mobilsol K [manufactured by Mobil Oil], Process oil X-100 [manufactured by Kyodo Oil], Dutrex 7
Examples include 29HP [manufactured by Showa Shell Sekiyu], Mitsubishi 34 heavy process oil [manufactured by Mitsubishi Oil], Comorex 200 [manufactured by Nippon Oil], or phenyl ether synthetic oil, which may be used alone or in combination with other oils. Process oil may also be used.

[0011] In the first invention, the process oil contains 100 parts by weight of CSM with a chlorine content of 30% or less,
In addition, in the second invention, 10 to 80 parts by weight, preferably 15 to 60 parts by weight, more preferably 20 parts by weight, respectively, per 100 parts by weight of the polymer consisting of component A and component B.
It is desirable to blend up to 40 parts by weight. The reason is 1.
If it is less than 0 parts by weight, it is difficult to say that the radiation resistance is sufficient.
This is because if it exceeds 80 parts by weight, the viscosity of the blended composition tends to become too low, making it difficult to put it into practical use.

The radiation-resistant composition of the present invention contains at least 3 parts by weight of an antiaging agent. Examples of anti-aging agents include amine-based, quinoline-based, dithioic acid-based, and benzimidazole-based anti-aging agents that are commonly used in rubber plastics. For example, poly(2,2,4-trimethyl-1,2-dihydroquinoline) [Nocrac 224, manufactured by Ouchi Shinko Kagaku], 4,4'-butylidene bis(3-methyl-6-tert-butylphenol) [Yoshinox BB, manufactured by Yoshitomi Pharmaceutical], N, N'-
Diphenyl-p-phenylenediamine [Nocrac D
P, manufactured by Ouchi Shinko Chemical], 2-mercaptobenzimidazole [Nocrac MB, manufactured by Ouchi Shinko Chemical], 4,4'-
Bis(α,α-dimethylbenzyl)diphenylamine [Naugard 445, manufactured by Uniroyal], nickel dibutyl dithiocarbamate [Nocrac NBC, manufactured by Ouchi Shinko Chemical], 6-ethoxy-2,2,4-trimethyl-
Examples include 1,2 dihydroquinoline [Nocrac AW, manufactured by Ouchi Shinko Kagaku], N,N'-di-β-naphthyl-p-phenylenediamine [Nonflex F, manufactured by Seiko Chemical], and the like.

[0013] In the first invention, the anti-aging agent is used in an amount of 100 parts by weight of CSM having a chlorine content of 30% or less.
Further, in the second invention, 3 to 15 parts by weight, preferably 3 to 10 parts by weight, more preferably 5 to 10 parts by weight, per 100 parts by weight of the polymer consisting of component A and component B.
It is preferable to mix parts by weight. The reason is that if it is less than 3 parts by weight, heat resistance and radiation resistance tend to be poor, and if it exceeds 15 parts by weight, crosslinking takes time and depending on the type, there is a risk of blooming. In addition, a combination of either an amine type or a quinoline type and a dithioic acid type (1 to 3 parts by weight) is particularly preferred from the viewpoint of heat resistance and radiation resistance.

[0014] The composition of the present invention is generally preferably in a crosslinked form. As a crosslinking agent, one that is usually used as a crosslinking agent for CSM, namely, tetramethylthuram monosulfide [Noxela TS, manufactured by Ouchi Shinko Kagaku]
, thurams such as dipentamethylenethuram tetrasulfide [Noxeler TRA, manufactured by Ouchi Shinko Chemical], tetramethylthuram disulfide [Noxeler TT, manufactured by Ouchi Shinko Chemical], dibenzothiazole disulfide [Soxynol DM, manufactured by Sumitomo Chemical], etc. Thiazoles, and N
, N'-m-phenylenemaleimide, etc., an acid acceptor such as litharge (PbO), dibasic lead phthalate, hydrotalcite, a mixed system containing sulfur if desired, Alternatively, a mixed system of an acid acceptor and a peroxide crosslinking agent is preferably used.

The total amount of the crosslinking agent and crosslinking aid (excluding the acid acceptor) is usually 2 to 10 parts by weight, preferably 2.5 parts by weight.
~8 parts by weight, and when a large amount of anti-aging agent is added,
In particular, when 5 parts by weight or more of an anti-aging agent is added to 100 parts by weight of CSM or the polymer, crosslinking is delayed, so it is desirable to blend the crosslinking agent in a larger amount than usual.

The radiation-resistant composition of the present invention may contain flame retardants such as antimony trioxide, zinc borate, magnesium hydroxide, aluminum hydroxide, decabromodiphenyl ether, brominated acenaphthylene, and halogen-based Flame retardants, processing aids such as stearic acid, ester waxes, and polyethylene waxes, fillers such as calcined clay, plate talc, calcium carbonate, and carbon, epoxies,
Additives such as organic phosphorous acid stabilizers and triazole ultraviolet inhibitors may be added.

The method for producing the radiation-resistant composition of the present invention includes:
There are no particular restrictions and this can be done in any way. For example, all components (including crosslinking agents and various additives) are kneaded in two rolls, a Banbury mixer, or a pressure kneader, or a polymer obtained by kneading only the polymer components in a Banbury mixer or a pressure kneader ( elastomer),
Examples include a method of mixing the remaining components. In either method, it is preferable that each compounding agent be homogeneously mixed and dispersed.

[0018] Furthermore, when producing molded articles using the composition of the present invention, no special molding method or molding conditions are required;
It can be sufficiently molded under normal rubber and thermoplastic resin molding conditions, and can be molded into various molded products such as tubular objects, containers, and plate-like objects.

When a wire coating material is obtained using the composition of the present invention, the material is extrusion coated using an extruder for rubber or thermoplastic resin, which is usually used for wire coating, and then continuously crosslinked. The appropriate crosslinking temperature is usually about 100 to 250°C, and the crosslinking time is about 1 minute to 1 hour.

[0020]

Effects of the Invention The radiation-resistant composition of the present invention shows little change in physical properties when exposed to high levels of radiation, and has excellent tensile properties.
Good heat resistance, workability, etc. Therefore, the composition of the present invention is particularly useful as a material for moldings in areas where high radiation doses are controlled, such as uranium enrichment facilities, radioactive waste treatment facilities, and spent fuel reprocessing facilities.

[0021]

EXAMPLES The present invention will be explained in more detail by Examples, Comparative Examples, and Test Examples, but the present invention is not limited thereto.

Examples 1 to 20 and Comparative Examples 1 to 9 Table 1 to
Each component was blended as shown in Table 3 and kneaded using two rolls to obtain each composition.

[0023]

[Table 1]

[0024]

[Table 2]

*1 Chlorosulfonated polyethylene with 35% Cl content (manufactured by DuPont) *2 Chlorosulfonated polyethylene with 24% Cl content (manufactured by DuPont) *3 Chlorosulfonated polyethylene with 25% Cl content (manufactured by Toso) *4 Amount of Cl 29% chlorosulfonated polyethylene [manufactured by Toso] *5 Cl content 30% chlorinated polyethylene [manufactured by Showa Denko] *6 Mineral oil wax [manufactured by Ouchi Shinko Chemical] *
7 Polyethylene wax [manufactured by DuPont] *8
Carbon black [manufactured by Chubu Carbon] *9 Sintered clay [manufactured by Engelhard] *10 Nickel dibutyl dithiocarbamate [manufactured by Ouchi Shinko Kagaku] *11 4,4'-bis(α,α-dimethylbenzyl)diphenylamine [Uniroyal ] *12 Poly(2,2,4-trimethyl-1,2-dihydroquinoline) [manufactured by Ouchi Shinko Chemical] *13 N,N'-diphenyl-p-phenylenediamine [manufactured by Ouchi Shinko Chemical] *14 Antimony trioxide [manufactured by Sumitomo Metal Mining] *15
Decabromodiphenyl ether [manufactured by Great Lakes] *16 Brominated acenaphthylene [manufactured by Toso] *17
Aromatic process oil [manufactured by Nippon Sun Oil] *18 Aromatic process oil [manufactured by Showa Shell Sekiyu] *19 Alkyl diphenyl ether [manufactured by Matsumura Sekiyu] *20 Lead monoxide [manufactured by Dainippon Paint Co., Ltd.] *21 Epoxy [ Manufactured by Dainippon Ink] *22 N,
N'-m-phenylene maleimide [manufactured by DuPont] *2
3 Dipentamethylenethuram tetrasulfide [manufactured by Ouchi Shinko Chemical] *24 Dibenzothiazyl disulfide [manufactured by Ouchi Shinko Chemical] *25 Dicumyl peroxide [manufactured by NOF] *2
6 1,1-bis(tert-butylperoxy)3
,3,5 Trimethylcyclohexane [manufactured by NOF]*
27 Triallylisocyanurate [manufactured by Nippon Kasei] *
28 Unable to prepare sample due to under crosslinking *29 Soft and unsuitable for practical use

[0026]

[Table 3]

*1 Chlorosulfonated polyethylene with a Cl content of 35% (manufactured by DuPont) *2 High Mooney viscosity chlorosulfonated polyethylene with a Cl content of 35% (manufactured by DuPont) *3 Chlorosulfonated polyethylene with a Cl content of 25% (manufactured by Toso) * 4 Epichlorohydrin [manufactured by Oso-Soviet Union] *5 Epichlorohydrin-ethylene oxide copolymer [manufactured by Oso-Soviet Union] *6 Mineral oil-based wax [manufactured by Ouchi Shinko Chemical] *7
Polyethylene wax [manufactured by DuPont] *8 Carbon black [manufactured by Chubu Carbon] *9 Sintered clay [manufactured by Engelhard] *10 Nickel dibutyl dithiocarbamate [manufactured by Ouchi Shinko Kagaku] *11 4,4'-bis (α, α -dimethylbenzyl)diphenylamine [manufactured by Uniroyal] *12 Poly(2,2,4-trimethyl-1,2-dihydroquinoline) [manufactured by Ouchi Shinko Chemical] *13 Antimony trioxide [manufactured by Sumitomo Metal Mining] *14
Decabromodiphenyl ether [manufactured by Great Lakes] *15 Brominated acenaphthylene [manufactured by Toso] *16
Aromatic process oil [manufactured by Nippon Sun Oil] *17 Pb
O acid acceptor [manufactured by Dainippon Toyo Co., Ltd.] *18 Dipentamethylenethulam tetrasulfide [manufactured by Ouchi Shinko Chemical] *19 N,N'-m-phenylene maleimide [manufactured by DuPont] *20 Dibenzothiazyl disulfide [manufactured by Shinko Ouchi] *21 2-Mercaptoimidazoline [manufactured by Ouchi Shinko Chemical] *22 Trilead tetroxide [manufactured by Dainippon Toyo Co., Ltd.] *23
The composition is too soft or under-crosslinked and cannot be measured.

Test Examples The compositions obtained in the above Examples and Comparative Examples were subjected to the following tests, and the results are listed in the tables.

[0029] Radiation Resistance A sample sheeted to a thickness of 2 mm was press-crosslinked at 170°C for 20 minutes. 1M rad/each seat
Cobalt irradiation was performed at 800M rad at a dose rate of hr, and tensile strength and elongation were measured in accordance with JIS K6301. After irradiation with 800M rad, those that maintained elongation of 50% or more were indicated as "○", and those that maintained elongation of less than 50% were indicated as "x".

[0030] Tensile properties A sheet sample with a thickness of 2 mm was press-crosslinked at 170°C for 20 minutes. Tensile strength and elongation were measured in accordance with JISK6301. Tensile strength is 1.0 kg/mm2 or less,
Or, those with an elongation of 150% or less were indicated as "x", and the others were indicated as "○".

[0031] Heat Resistance A 2 mm thick sheet sample was press-crosslinked at 170°C for 20 minutes. Then, it was aged in a gear at 120° C. for 7 days. Tensile strength and elongation were measured in accordance with JIS K6301, and the remaining percentages relative to their respective initial values were determined. When the remaining elongation was 40% or more, it was indicated as "○", and when it was less than 40%, it was indicated as "x".

■ Processability Each composition was extruded into a 10 mmφ tube using a 30 mmφ extruder under the following conditions.

Dice 90°C
2 ~ C1 70℃ screw rotation
30 rpm Those with a smooth appearance were marked as "○", and those with poor appearance or too soft that the extrudate was deformed were marked as "x".

Claims (3)

[Claims] 1. A radiation-resistant composition comprising chlorosulfonated polyethylene having a chlorine content of 30% or less, an acid acceptor, a process oil, and an antiaging agent. 2. Consisting of chlorosulfonated polyethylene (component A), epichlorohydrin or a copolymer of epichlorohydrin and ethylene oxide (component B),
A radiation-resistant composition comprising a polymer, an acid acceptor, a process oil, and an anti-aging agent having a weight ratio of component A/component B of 95/5 to 50/50. 3. 3 to 1 part of acid acceptor per 100 parts by weight of the chlorosulfonated polyethylene or the polymer.
3. The radiation-resistant composition according to claim 1, further comprising: 0.00 parts by weight, 10 to 80 parts by weight of a process oil, and 3 to 15 parts by weight of an antiaging agent.