JPS6337146B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a polymer composition with greatly improved radiation resistance. [Prior Art] Organic polymer materials used in nuclear reactors, breeder reactors, radioactive waste treatment facilities, or ionizing radiation generators, such as electric wires, cables, and various equipment, are constantly exposed to a considerable amount of radiation. There is. These polymeric materials exposed to high doses of radiation in the air generally harden and become brittle, losing flexibility or becoming soft, resulting in significantly deteriorated properties. Therefore, polymer compositions used for covering insulation materials, packing materials, sealing materials, frames, hose materials, etc. for electric wires and cables for such purposes must be highly radiation resistant from an economic and safety standpoint. Research is progressing on technology to impart radiation resistance to polymeric materials. The following general formula for high molecular weight polymers [] (In formula [], X is chlorine or bromine, a is 0-
2, b represents 1 to 6, n represents an integer of 1 or more) By blending the halogenated acenaphthylene and/or its condensate, high radiation resistance and excellent flame retardance can be imparted to the polymer. It is known that it is possible to impart sex (Japanese Patent Publication No. 58-1146, Japanese Patent Publication No. 60-25063). When the halogenated acenaphthylene and/or its condensate is blended into a high molecular polymer, the halogenated acenaphthylene and/or its condensate is usually melted and dispersed in the high molecular polymer by heating during kneading or hot molding. use. Furthermore, by utilizing the radical polymerization reaction of the double bond between carbon 1 and carbon 2 of the halogenated acenaphthylene unit, a free radical generation treatment is performed after molding to graft the high molecular weight polymer. It is known that these methods can improve the radiation resistance and flame retardancy of high molecular weight polymers. [Problems to be Solved by the Invention] The present inventors have repeatedly investigated the effect of halogenated acenaphthylene and/or its condensate on imparting radiation resistance to high molecular weight polymers, and have found that variations in processing conditions and halogenated It was recognized that there were large differences in the expression of radiation resistance due to differences in the quality of acenaphthylene and/or its condensates. That is, when halogenated acenaphthylene and/or its condensate is blended into polyolefin resin, rubber, etc., when the processing temperature is lower than the melting temperature of halogenated acenaphthylene and/or its condensate, or when the halogenated acenaphthylene condensate is condensed. When the composition is high, a phenomenon in which the elongation rate at the breaking point, which is a criterion for determining radiation resistance, decreases was observed, which was a problem. The object of the present invention is to produce halogenated acenaphthylene and/or
Another object of the present invention is to provide a polymer composition that stably exhibits high radiation resistance while suppressing the influence of the quality of its condensate. [Means for Solving the Problems] In view of the problems of the prior art, the present inventors have conducted intensive studies on a method for developing radiation resistance in a polymer composition containing halogenated acenaphthylene and/or its condensate. As a result, we found that due to differences in processing and molding conditions and the quality of halogenated acenaphthylene and/or its condensate, the dispersibility and compatibility in the polymer were slightly different, which greatly affected the development of radiation resistance. I found out what to do. In order to solve this problem, we are actively searching for a dispersion improver that improves the dispersibility of halogenated acenaphthylene and/or its condensate within the polymer and does not adversely affect the physical properties of the polymer composition. I went to As a result, we found that various polymer resins, rubbers, sether plasticizers, paraffinic and aromatic process oils, and various lubricants had little effect on improving dispersibility, but the following general formula [] (In the formula [], R ₁ and R ₂ represent hydrogen, alkyl, alkoxy, phenyl, phenoxy, diphenyloxy, or terphenyloxy groups.) It has been found that the dispersibility of halogenated acenaphthylene and/or its condensate in a polymer can be significantly improved, and the radiation resistance of a polymer composition can be improved and stably expressed. Furthermore, it was discovered that the blending of this diphenyl ether derivative does not adversely affect the crosslinking properties or electrical/mechanical properties of the high molecular weight polymer, leading to the completion of the present invention. [Function] The reason why radiation resistance is improved by improving the dispersibility of halogenated acenaphthylene and/or its condensate in polymers is not necessarily clear, but uniform dispersion improves the radiation resistance of acenaphthylene derivatives. This acenaphthylene derivative effectively acts as a trap site for the excitation energy generated by the acenaphthylene derivative, increasing the transfer efficiency of excitation energy and effectively capturing the generated polymer radicals, suppressing polymer deterioration and exhibiting radiation resistance. it is conceivable that. A more detailed explanation will be given below. The radiation-resistant polymer composition of the present invention is achieved by blending a high molecular weight polymer, halogenated acenaphthylene and/or its condensate, with a diphenyl ether derivative. Examples of the polymers whose radiation resistance is improved according to the present 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- Propylene-grafted vinyl chloride copolymer, chlorinated polyethylene, chlorinated polyethylene-grafted vinyl chloride copolymer, polyamide, thermoplastic resin or elastomer such as acrylic resin, polyester, polyurethane, epoxy resin, phenolic resin, melamine resin, urea Examples include thermosetting resins such as resins, butyl rubber, chloroprene rubber, nitrile rubber, natural rubber, silicone rubber, chlorosulfonated polyethylene, styrene-butadiene rubber, styrene-butadiene-acrylonitrile copolymer, polyester-ether elastomer, etc. Ru. Among them, polyolefin resins represented by polyethylene and polyolefin elastomers represented by ethylene-propylene-diene copolymers are general-purpose polymers that have excellent properties such as electrical properties and chemical resistance. The flammability can also be improved according to the present invention, making it the most suitable polymer. The halogenated acenaphthylene and/or its condensate as used in the present invention has the following general formula [] (In formula [], X is chlorine or bromine, a is 0-
2, b represents 1 to 6, n represents an integer of 1 or more), and is a compound containing at least one halogen atom on the aromatic ring of acenaphthylene, and in the condensate, halogenated acenaphthene is formally The Friedel-Crafts reaction causes condensation to form a multimer with a degree of condensation of 2 or more, followed by a dehydrobromination reaction to produce a carbon-carbon double bond at the benzyl position. The bonding mode of the condensate is an intermolecular bond between the benzylic carbon of acenaphthylene and the aryl carbon of acenaphthylene. The connection point is, for example, 1
(or 2), 5′− Or 1 (or 2), 6'- etc., but there are also 1 (or 2),
3'-, 1 (or 2), 4'-, 1 (or 2),
Possible combinations include 7'-, 1 (or 2), and 8'-. Those with a degree of bonding of 3 or more are those in which the number of constituent units is increased by any of these bonds. The condensate used in the present invention refers to a condensation product having a degree of condensation of 10 or less and having excellent compatibility with resin. The amount of these halogenated acenaphthylenes and/or their condensates in the high molecular weight polymer is as follows:
At the lower limit, to ensure good radiation resistance, and at the upper limit, to ensure elongation characteristics, flexibility, etc. of the polymer composition, 5 parts per 100 parts by weight of the polymer.
The amount is preferably 150 parts by weight. Next, the diphenyl ether derivative referred to in the present invention has the following general formula [] (In the formula [], R ₁ and R ₂ represent any one of hydrogen, alkyl, alkoxy, phenyl, phenoxy, diphenyloxy, and terphenyloxy groups) or a mixture thereof. For example, specifically, diphenyl ether, monoalkyl diphenyl ether, dialkyl diphenyl ether, monoalkoxy diphenyl ether, dialkoxy diphenyl ether, phenoxy diphenyl, phenyl phenoxy diphenyl, phenoxy Examples include sidiphenyl ether, diphenoxydiphenyl ether, phenoxyphenoxydiphenyl, phenoxyphenoxyterphenyl, and the like. The blending amount of this diphenyl ether derivative is based on halogenated acenaphthylene and/or condensate.
A range of 1 to 100 parts by weight is selected based on 100 parts by weight. The reason for this is that if the amount is less than 1 part by weight, the effect of uniformly dispersing the halogenated acenaphthylene and/or its condensate in the polymer is insufficient, while if it exceeds 100 parts by weight, the effect of increasing the amount is insufficient. This is because it is rarely seen. The composition of the present invention may be added with suitable reinforcing agents, extenders, pigments, lubricants, vulcanizing agents, crosslinking aids, anti-aging agents, ultraviolet inhibitors, and flame retardant aids depending on the purpose of use. There is no problem in adding an appropriate amount of agents and the like as long as the properties are not deteriorated. In the formulation of the present invention, halogenated acenaphthylene and/or its condensate and diphenyl ether derivative are blended into a high molecular weight polymer, and the mixture is sufficiently heated during kneading to form a polymer with halogenated acenaphthylene and/or its condensate. Uniformly melt and disperse in the polymer. Furthermore, when molding this polymer composition, a chemical crosslinking method in which an organic peroxide such as dicumyl peroxide is mixed and heated, and ionizing radiation such as β rays, γ rays, and electron beams are irradiated. Depending on the type of resin, it is possible to carry out a free radical generation treatment using a so-called radiation crosslinking method to graft a halogenated acenaphthylene and/or its condensate onto a polymer substrate, and at the same time crosslink the polymer. It is valid. [Example] The present invention will be further explained below with reference to Examples, but the present invention is not limited thereto. Examples 1 to 3 and Comparative Examples 1 to 2 Compounding agents were added to the ethylene-propylene-diene copolymer so as to have the composition shown in Table 1. In each of the following examples, the unit of amount of each component is parts by weight. After uniformly kneading all ingredients except the free radical generator using a heated roll at 160℃, the free radical generator was further kneaded at 20℃.
Added at ~70°C. Further, these were heated under pressure in a hot press at 160° C. for 30 minutes to form a sheet with a thickness of 1 mm. The halogenated acenaphthylene and/or its condensate used in this example is the following brominated acenaphthylene condensate composition. Bromine content 55.7% Melting point 125-143℃ Condensation composition Monomer 19.0% Dimer 19.5% Trimer 18.9% 4-8mer 42.6% The condensation composition is TSK gel G1000H8 as a filler.
(manufactured by Toyo Soda Kogyo Co., Ltd.) Inner diameter 7.5 mm x length
It was determined by high performance liquid chromatography using a 600 mm column. The obtained composition sheet was irradiated with 200 Mrad of gamma rays at a dose rate of 0.5 Mrad/hr in air at room temperature. The mechanical properties before and after irradiation were measured according to JIS C 3005, and the results of evaluating the radiation resistance of each sample are shown in Table 1. Furthermore, changes in the grafting rate of halogenated acenaphthylene and/or its condensate to the polymer before and after irradiation with gamma rays were determined by Soxhlet extraction using tetrahydrofuran. The results obtained are shown in Table 1. In addition, the dispersibility of the brominated acenaphthylene condensate on the surface of each sheet was measured using an X-ray microanalyzer.
FIG. 1 shows the dispersibility of the sheet of Example 1, and FIG. 2 shows the dispersibility of the sheet of Comparative Example 1, as measured by BrKα radiation. The white part indicates the presence of bromine atoms.

【table】

[Table] As is clear from Table 1 and Figure 1, when a brominated acenaphthylene condensate with a high condensation composition is blended, the addition of the diphenyl ether derivative of the present invention aims to uniformly disperse it, and radiation It can be seen that the mechanical properties after irradiation are also excellent, and in particular, the deterioration of elongation properties is suppressed. On the other hand, when no diphenyl derivative is added (Comparative Example 1),
As seen in Figure 2, due to uneven dispersion due to partial aggregation of the brominated acenaphthylene condensate,
Mechanical properties deteriorate significantly after radiation irradiation. Further, when only the diphenyl ether derivative was added (Comparative Example 2), the radiation resistance was not improved. γ due to homogeneous dispersion of brominated acenaphthylene condensate
The grafting rate was improved before and after radiation irradiation, and γ
This shows that in addition to the effect of promoting the transfer of excitation energy during irradiation, the polymer radicals generated during γ-ray irradiation are effectively captured. Furthermore, the addition of diphenyl ether derivatives has almost no adverse effect on the crosslinking and special properties of the polymer. Examples 4 and 5 and Comparative Examples 3 and 4 Compounding agents were added to polyethylene so as to have the composition shown in Table 2, and these were thoroughly kneaded using heated rolls, and the resulting composition was heated to 160°C. Press molding was performed for 30 minutes to create a 1 mm thick sheet. For each sheet obtained, the dispersibility of the brominated acenaphthylene condensate, initial mechanical properties, and properties after irradiation with 200 Mrad of gamma rays were measured, and the results are shown in Table 2.

【table】

〔Effect of the invention〕

As explained above, the polymer composition of the present invention is
By adding the diphenyl ether derivative, it is possible to uniformly disperse the halogenated acenaphthylene and/or its condensate into the polymer, and the radiation resistance function of the polymer composition can be stably expressed. It is useful for structural materials, coating insulation materials, packing materials, sealing materials, etc. in areas exposed to radiation.

[Brief explanation of the drawing]

Figure 1 is a photograph of the dispersibility of the brominated acenaphthylene condensate on the surface of a molded sheet of the polymer composition of the present invention, measured with an X-ray microanalyzer;
The figure is a measurement photograph of a comparative example.

Claims (1)

[Claims] 1. The polymer has the following general formula [] (In formula [], X is chlorine or bromine, a is 0-
2, b represents 1 to 6, n represents an integer of 1 or more) halogenated acenaphthylene and/or its condensate represented by the following general formula [] (In formula [], R ₁ and R ₂ represent any one of hydrogen, alkyl, alkoxy, phenyl, phenoxy, diphenyloxy, and terphenyloxy groups). Radiation-resistant polymer composition. 2. The radiation-resistant polymer composition according to claim 1, wherein the amount of the halogenated acenaphthylene and/or its condensate is 5 to 150 parts by weight based on 100 parts by weight of the polymer. 3. The amount of diphenyl ether derivative is halogenated acenaphthylene and/or its condensate.
The radiation-resistant polymer composition according to claim 1 or 2, wherein the amount is 1 to 100 parts by weight per 100 parts by weight. 4. Any one of claims 1 to 3, wherein the polymer is any resin or elastomer selected from the group of thermoplastic resins, thermosetting resins, and natural or synthetic rubbers. Radiation-resistant polymer composition. 5. The radiation-resistant polymer composition according to any one of claims 1 to 4, wherein the polymer is a polyolefin resin or a polyolefin elastomer.