JP3065873B2 - Radiation resistant flame retardant resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant resin composition excellent in radiation resistance, and more particularly, to 8MGy to 10M.
The present invention relates to a radiation-resistant flame-retardant resin composition which exhibits good radiation resistance even under high radiation of about Gy.

[0002]

2. Description of the Related Art With the development and expansion of nuclear power plants, it has been desired to efficiently recycle nuclear fuel. Therefore, nuclear fuel reprocessing facilities and nuclear fuel enrichment facilities have been constructed. I have. Very high levels in such facilities, for example 8 MGy to 10 M
There are many control areas exposed to radiation of about the Gy dose, and various members used in these areas are required to have high radiation resistance. In particular, in addition to radiation resistance, various characteristics such as flame retardancy and mechanical strength are required for electric wires and cables laid in the management area.

Heretofore, as a radiation-resistant flame-retardant resin composition, hydrated metal oxides such as aluminum hydroxide and quinoline have been used for ethylene-ethyl acrylate-based copolymers and ethylene-methyl acrylate-based copolymers. There have been radiation-resistant flame-retardant resin compositions containing a compound based antioxidant (JP-A-4-314758, JP-A-4-170459,
JP-A-5-93105).

[0004] However, the above radiation-resistant flame-retardant resin composition cannot be said to have sufficient radiation resistance for use under high radiation of about 8 MGy to 10 MGy dose.

[0005] An object of the present invention is to provide a material having little change in physical properties such as tensile properties even under high radiation and having flame retardancy.
In particular, it is an object of the present invention to provide a radiation-resistant flame-retardant resin composition suitable as a covering material for electric wires and cables laid under a high level of radiation of about 8 to 10 MGy.

The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems. As a result, the above-mentioned problems were solved with respect to 100 parts by weight of an ethylene-methyl acrylate copolymer having a methyl acrylate content of 40 to 70% by weight. 50 to 200 parts by weight of a mixture of huntite and hydromagnesite, and 0.5 to 30 parts by weight of a quinoline-based antioxidant, and the composition ratio of huntite and hydromagnesite is 10 to 90% by weight: The problem is solved by a radiation-resistant flame-retardant resin composition in the range of 90 to 10% by weight.

According to the present invention, a specific polymer is blended with huntite, hydromagnesite, and a quinoline-based antioxidant so that an ethylene-acrylate copolymer can be treated with aluminum hydroxide or the like. A composition comprising a hydrated metal oxide and a quinoline-based antioxidant has an unsatisfactory radiation resistance of about 8 MGy to 10 MGy, and has excellent flame resistance and good bleed characteristics. It can be a flame-retardant resin composition.

Next, the materials used in the present invention will be described in detail. Examples of the ethylene-acrylate polymer used in the present invention include ethylene-methyl acrylate, ethylene-ethyl acrylate copolymers, and the like. Ethylene-methyl acrylate-unsaturated silane compound polymer, ethylene-ethyl acrylate-unsaturated silane compound polymer, ethylene-methyl acrylate-maleic anhydride polymer, ethylene-ethyl acrylate-anhydride copolymerized with a compound or maleic anhydride A maleic acid polymer may be used, and ethylene-
A terpolymer in which a crosslinking site monomer represented by Chemical Formula 1 or Chemical Formula 2 is introduced into an acrylate polymer may be used.

[0009]

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[0010]

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The ethylene-ethyl acrylate copolymer has an ethyl acrylate content of, for example, 10
-80% by weight, preferably 30-75% by weight. The ethylene-methyl acrylate copolymer has a methyl acrylate content of, for example, 10 to 80% by weight, and preferably 30 to 75% by weight. Among them, preferred is an ethylene-methyl acrylate copolymer having a methyl acrylate content of 30 to 75% by weight, particularly 40 to 70% by weight.

Commercially available ethylene-acrylate polymers include Sumitomo Chemical Co., Ltd. ethylene-acrylate copolymer EMA2152 (acrylate content 59%), and Mitsui DuPont Chemical Co., Ltd. ethylene-acrylate copolymer.
Evaflex A709 of ethyl acrylate copolymer
(Ethyl acrylate content 35%).

As the ethylene-propylene polymer,
Ethylene-propylene copolymer or / and ethylene-
Propylene-diene polymers can be used. The ethylene / propylene molar ratio of the ethylene-propylene copolymer is from 20/80 to 80/20, preferably 40/80.
60 to 60/40. Examples of the diene of the ethylene-propylene-diene polymer include 1,4 hexadiene, dicyclopentadiene, and ethylidene norbornene, and dicyclopentadiene is particularly preferred. Ethylene-
The iodine value of the propylene-diene polymer is preferably from 1 to 10, particularly preferably from 2 to 6, from the viewpoint of improving radiation resistance.

[0014] Examples of commercially available ethylene-propylene-based polymers include Sumitomo Chemical's ethylene-propylene-diene polymer P2121 (iodine value 2) and Sumitomo Chemical's ethylene-propylene-diene polymer P2120 (iodine value). Value 4), EP43 (iodine value 6) of an ethylene-propylene-diene polymer manufactured by Nippon Synthetic Rubber Co., Ltd.

The thermoplastic urethane elastomer includes:
Known materials such as adipate, adipate ester, ether, caprolactone, carbonate and polycarbonate can be used, and carbonate is preferred. Commercially available thermoplastic urethane elastomers include Rezamine P1045 (adipate ester type) manufactured by Dainichi Seika Kogyo Co., Ltd.
060 (ether type), Rezamine P8 manufactured by Dainichi Seika Kogyo Co., Ltd.
80 (carbonate ester type).

Huntite used in the present invention is, for example, Mg
₃ Ca (CO ₃ ) ₄ may be used. Also, known hydromagnesite can be used, for example, Mg
_X (CO ₃ ) _Y (OH) _Z · nH ₂ O, X = 3-5, Y
= 2-4, Z = 1-3, n = 1-5, preferably Mg
₄ (CO ₃ ) ₃ (OH) ₂ .3H ₂ O.

The amount of huntite and hydromagnesite is 50 to 200 parts by weight of a mixture of huntite and hydromagnesite with respect to 100 parts by weight of the ethylene-acrylate polymer and / or the ethylene-propylene polymer. Parts, preferably 70-150 parts by weight,
Particularly preferably, 80 to 140 parts by weight are blended. The composition ratio of huntite to hydromagnesite is preferably in the range of 10 to 90% by weight: 90 to 10% by weight, more preferably 20 to 80% by weight: 80 to 20% by weight. If the total amount of huntite and hydromagnesite is less than 50 parts by weight, the flame retardancy is insufficient and
If the amount is more than 00 parts by weight, the radiation resistance and the initial tensile properties tend to decrease. As a commercial product of Huntite,
MICROLINE MINERALS & CHEM
ICALS LIMITED Ultra Curve C5-
10 (a mixture of huntite and hydromagnesite), Ultra Curve U5 (a mixture of huntite and hydromagnesite), and the like.

In the present invention, a quinoline antioxidant is used. As the quinoline-based antioxidant, known ones can be used. For example, 2,2,4-trimethyl-1,2-
Polymer of dihydroquinoline, 6-ethoxy-2,2,4
-Trimethyl-1,2-dihydroquinoline, 6-dodecyl-2,2,4-trimethyl-1,2-dihydroquinoline, derivatives of trimethyldihydroquiniline and the like. Particularly, a polymer of 2,2,4-trimethyl-1,2-dihydroquinoline is preferable from the viewpoint of radiation resistance. Commercially available quinoline-based antioxidants include Nocrack 224 manufactured by Ouchi Chemical Shinko Co., Ltd. and Nocrack AW manufactured by Ouchi Chemical Shinko Co., Ltd.
Is exemplified. The compounding amount of the quinoline-based antioxidant is 0.5 to 100 parts by weight of the ethylene-acrylate polymer and / or the ethylene-propylene polymer.
To 30 parts by weight, preferably 1.0 to 20 parts by weight, particularly preferably 2.0 to 10 parts by weight. If the quinoline-based antioxidant is less than 0.5 part by weight, the radiation resistance tends to decrease, and if it exceeds 30 parts by weight, the initial tensile properties tend to decrease.

In the present invention, when an ethylene-acrylate polymer and / or an ethylene-propylene polymer are mainly used, it is preferable to crosslink from the viewpoint of improving heat resistance and mechanical strength. As the crosslinking method, known methods such as chemical crosslinking, water crosslinking, and radiation crosslinking can be applied.

When the radiation-resistant flame-retardant resin composition used in the present invention is chemically crosslinked, for example, dicumyl peroxide, 1,1-bis (t-butylperoxy) 3,3,5
-An organic peroxide-based crosslinking agent such as a peroxide such as trimethylcyclohexane, an ethylene-acrylate polymer or / and an ethylene-propylene polymer 1
1 to 5 parts by weight, preferably 2 to 4 parts by weight, is added to 00 parts by weight. When an ethylene-propylene-diene polymer is mainly used, sulfur-based vulcanization can be performed. Further, from the viewpoint of improving the mechanical characteristics, N, N
It is preferable to add a crosslinking aid such as' -m-phenylenebismaleimide, zinc methacrylate, and TAIC.

The radiation-resistant flame-retardant resin composition used in the present invention contains a stabilizer, a silane-based or titanate-based coupling agent, talc, clay, silica, calcium carbonate, or the like to such an extent that the object of the present invention is not impaired. Fillers such as magnesium carbonate, magnesium silicate carbonate, kaolin, montmorillonite, zeolite, titanium oxide, mica, diatomaceous earth, wollastonite, alumina, magnesia, flame retardants such as aluminum hydroxide, magnesium hydroxide, and red phosphorus, plasticizers , A lubricant, and the like. Further, an antioxidant such as diphenylamine or phenol may be added.

The radiation-resistant flame-retardant resin composition of the present invention is kneaded by a usual kneading means, for example, a Banbury mixer, a Hensle mixer, a kneader, a roll, a blender, and the like, and then using a molding machine such as an extruder. It can be processed into a desired product having a desired shape, such as an electric wire, a tape, and a tube.

(Examples 1 to 8) Each of the examples having the component constitutions shown in Table 1 was adjusted with a two-roll mill.
Cross-linked by hot press molding at 20 ° C for 20 minutes, thickness 1mm
Crosslinked sheet.

[0024]

[Table 1]

However, the following ingredients were used in Table 1. 1) Sumitomo Chemical Co., Ltd. ethylene-acrylate copolymer EMA2155 (acrylate content: 59% by weight, FEF carbon black: 10 parts by weight) 2) Sumitomo Chemical Co., Ltd. ethylene-acrylate copolymer EMA2755 (acrylic) (Acid ester content: 59% by weight, 2.3% by weight of crosslinking site monomer, 10% by weight of FEF carbon black) 3) DuPont ethylene-methyl acrylate copolymer Baymac G (methyl acrylate content: 55% by weight, 4) Ethylene-propylene-diene polymer Esplen 301 (Iodine value 10) 5) Sumitomo Chemical thermoplastic urethane elastomer Rezamin P880 (carbonate ester type) 6) Sumitomo Chemical Ethylene-maleic anhydride polymer Dine TX8030 7) MICROFINE MINERALS & CH
EMICALS LIMITED Ultra Curve C
5-10 (mixture of huntite and hydromagnesite) 8) Diamond Black H manufactured by Mitsubishi Kasei Co., Ltd. 9) Adeka fatty acid SA-200 manufactured by Asahi Denka Co., Ltd. 10) Lubricant A of Dainichi Seika Kogyo Co., Ltd. 11) Farmin 80D 12 manufactured by Kao Corporation ) Nouchikku 224 manufactured by Ouchi Shinko Chemical Co., Ltd. 13) Nocrack AW manufactured by Ouchi Shinko Chemical Co., Ltd. 14) Adecaizer PN-650 manufactured by Asahi Denka Co., Ltd. 15) Sansen 4240 manufactured by Nippon Sun Oil Co., Ltd. ) NOF Corporation Percumyl D 18) available from Nippon Kasei chemical Co. TAIC 19) Asada Kagaku Co. Al (AA) ₂ OH 20) Asada Kagaku Co. Zn (AA) ₂ CP 21) manufactured by Sumitomo chemical Co. Ebateto M5011 (acetate content 35 22) Heidilite H-42M manufactured by Showa Denko Co., Ltd. 23) Nocrack DP manufactured by Ouchi Shinko Chemical Co., Ltd. 24) Nokuku manufactured by Ouchi Shinko Chemical Co., Ltd. Click MB

The crosslinked sheets of the respective examples prepared as described above were subjected to radiation resistance, initial mechanical properties, flame retardancy, and bloom test.

[0027] 1) a sheet having a thickness of 1mm were prepared from compositions shown in each example radiation resistance test, room temperature, 8MGy under air atmosphere, gamma rays Co ⁶⁰ (the dose rate of about 10 KGy / h) Irradiated, the tensile properties of the irradiated sample were measured according to JIS K6301. When the elongation was 50% or more, it was evaluated as ○, and when it was less than 50%, it was evaluated as x.

2) Initial Mechanical Properties Tensile strength and elongation were measured using the sheets of the examples according to JIS K6301. Tensile strength ○ things 0.6 kg / mm ² or more, 0.6 kg / m
and × those less than m ^2, those elongation of more than 200% ○, and as × of less than 200%.

3) Flame retardancy The sheet of each example was measured for oxygen index (LOI) according to the test method of JIS K7201 (oxygen index method). A sample having an oxygen index of 27 or more was evaluated as ○, and a sample having an oxygen index less than 27 was evaluated as ×.

4) Bloom test A 1 mm-thick sheet prepared from the composition shown in each example was allowed to stand at room temperature for 7 days, and then the state of the sheet surface was visually observed. When no change was observed, ○ was given, and when the powder was wiped, or a liquid oozed out, × was given.

(Comparative Examples 1 to 6) Each component shown in Table 2 was adjusted with two rolls in the same manner as in the example,
It was press-molded and cross-linked under the conditions of 20 minutes to prepare a cross-linked sheet having a thickness of 1 mm, and measured for each evaluation item in the same manner as in the examples.

[0032]

[Table 2]

[0033]

The radiation-resistant flame-retardant resin composition according to the present invention comprises:
It has little change in physical properties such as tensile properties even under high radiation, has non-halogen flame retardancy, and has good bloom properties. Therefore, as various materials used in a control area exposed to an extremely high level of radiation of about 8 MGy to 10 MGy in a nuclear fuel reprocessing facility, a nuclear fuel enrichment facility, and the like, particularly as a covering material for electric wires and cables laid in the area. It is preferably used, and the safety of nuclear facilities is further improved.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification code FI C08K 5: 3432) (56) References JP-A-4-314752 (JP, A) JP-A-4-268350 (JP, A) JP-A-2-251572 (JP, A) JP-A-2-45567 (JP, A) JP-A-3-137144 (JP, A) JP-A-5-170984 (JP, A) West Germany Patent Application Publication 3334730 (DE, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 23/08 C08L 23/16 C08L 75/04 C08L 33/08 C08K 13/02 C08K 3/26 C08K 5/3432

Claims (1)

(57) [Claims] 1. A methyl acrylate content of 40 to 7
50 to 200 parts by weight of a mixture of huntite and hydromagnesite and 0.5 to 30 parts by weight of a quinoline antioxidant are added to 100 parts by weight of an ethylene-methyl acrylate copolymer which is 0% by weight. And the composition ratio of huntite to hydromagnesite is 10 to 90
% By weight: a radiation-resistant flame-retardant resin composition in the range of 90 to 10% by weight.