KR101409621B1 - Long-term life polyolefin resin compositions for the extreme materials of the nuclear power plant - Google Patents

Abstract

In a resin composition for use as a semi-conductor layer or a jacket of a non-safety grade (Non Class 1E, non-radiation area) power line of a nuclear power plant, a resin composition having an optimum composition is proposed to maximize heat resistance and radiation resistance of a power line, A resin composition capable of sufficiently satisfying a long-term service life is disclosed. The present invention relates to a resin composition comprising 40 to 60 parts by weight of an ethylene vinyl acetate copolymer (EVA) And 40 to 60 parts by weight of low density polyethylene (LDPE); 90 to 130 parts by weight of a flame retardant; 2 to 6 parts by weight of an antioxidant; 3 to 7 parts by weight of a crosslinking agent; 3 to 7 parts by weight of carbon black; And 3 to 7 parts by weight of a processing aid; and a resin composition for a semiconductive layer or jacket of a non-class 1E (non-radiation area) power line and a method for producing the resin composition.

Description

TECHNICAL FIELD [0001] The present invention relates to a long-life polyolefin resin composition for a nuclear power plant, and to a method for producing the same. BACKGROUND ART < RTI ID = 0.0 >

The present invention relates to a long-life polyolefin resin composition for a nuclear power plant, and more particularly to a resin composition for a semiconductive or jacket of a non-class 1E (non-radiation area) power line of a nuclear power plant, ≪ / RTI >

Generally, nuclear power plants are divided into safety class (Class 1E, radiation zone) and non-safety class (Non Class 1E, non-radiation zone), safety grade zone has cumulative annual dose of 200Mrad, It is a grade.

Power lines used in nuclear power plants serve to supply power, control equipment, and transmit communication signals inside the nuclear power plant. Because of the danger of radioactive exposure to nuclear power plant accidents, it is necessary to control the equipment through electrical signals rather than people. Therefore, the stability of power lines is important because power lines are damaged or short-circuited.

Recently, the life span of power lines has been extended from 40 years to 60 years due to the extended working life of nuclear power plants. However, the ethylene vinyl acetate resin used for the semi-conductor layer of the non-safety grade power line of a nuclear power plant is poor in heat resistance and radiation resistance, and thus has not satisfied the long-term service life.

Open Patent Publication No. 2010-0092244 discloses a flame retardant insulating resin composition comprising an antioxidant and a flame retardant in an ethylene copolymer composed of ethylene-butene, ethylene-vinyl acetate and ethylene-propylene-diene rubber and having heat resistance and radiation resistance , But it is difficult to confirm whether the long-life requirement is satisfied. This is because the radiation resistance after evaluating the tensile strength and the residual rate after irradiation is evaluated and most of the compositions irradiated with the radiation show a residual rate of 75% or less of the standard value, which means that the compositions do not satisfy the long- . Also, since the long-term life evaluation through heat-accelerated deterioration is not performed, it is difficult to accurately evaluate the life.

In addition, JP-A-2008-0083172 discloses a composition in which carbon nanotubes are added to a base resin formed of ethylene vinyl acetate to improve radiation resistance and oxidation resistance. However, since the solution mixing method is used during production, There is a problem in terms of.

Accordingly, in a resin composition for use as a semiconductive layer or jacket of a non-safety class (non-class 1E, non-radiation area) power line of a nuclear power plant, it is desired to provide a resin composition having improved heat resistance and radiation resistance, Development of a resin composition excellent in manufacturing efficiency is desired.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above problems, and it is an object of the present invention to provide a resin composition for use as a semiconductive layer or jacket of a non-class 1E (non-radiation area) power line of a nuclear power plant, To provide a resin composition capable of maximizing the heat resistance and radiation resistance of a power cable and satisfying an extended long-term life requirement.

It is another object of the present invention to provide a resin composition having an optimum composition by a simple method, thereby providing a resin composition having excellent manufacturing efficiency.

In order to solve the above problems, the present invention provides a thermoplastic resin composition comprising 40 to 60 parts by weight of an ethylene vinyl acetate copolymer (EVA) And 40 to 60 parts by weight of low density polyethylene (LDPE); 90 to 130 parts by weight of a flame retardant; 2 to 6 parts by weight of an antioxidant; 3 to 7 parts by weight of a crosslinking agent; 3 to 7 parts by weight of carbon black; (Non-Class 1E, non-radiation area) power line comprising 3 to 7 parts by weight of a polyolefin resin and 3 to 7 parts by weight of a processing aid.

The ethylene vinyl acetate copolymer has a vinyl acetate component content of 20 to 35 mol% and a melt index (ASTM 1238, 190 DEG C, 2.16 kgf) of 1 to 6 g / 10 min. (Non Class 1E, non-radiation area) power line.

The low density polyethylene has a density of 0.915 to 0.925 g / cm 3 and a melt index (ASTM 1238, 190 캜, 2.16 kgf) of 6 to 10 g / 10 min. Non-radiation area) power line.

The flame retardant may be at least one selected from the group consisting of magnesium hydroxide, aluminum hydroxide, and talc. The non-safety grade (Non-Class 1E, non-radiation area) Lt; / RTI >

In addition, the antioxidant is composed of 1 to 3 parts by weight of a primary antioxidant and 1 to 3 parts by weight of a secondary antioxidant. The non-safety grade (Non-Class 1E, non-radiation area) And a resin composition.

The primary antioxidant may be 2,6-di-t-butyl-4-methylphenol, tetrakis [methylene-3- (3,5 (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane), 2,2- Methylenebis (4-methyl-6-t-butylphenol) and octadecyl-3,5-di-tertiary-butyl- (Non-Class 1E, non-radiation area) characterized in that it is at least one selected from the group consisting of octadecyl-3,5-di-t-butyl-4-hydroxyhydrocinnamate. A resin composition for a semiconductive layer or a jacket of a power line is provided.

The second antioxidant may be tris (2,4-di-t-butylphenyl) phosphite, bis (2,4-di- (Non-safety grade) of nuclear power plant characterized in that it is at least one selected from the group consisting of bis (2,4-di-t-butyl) pentaerythritol diphosphite and alkylester phosphite. Class 1E, non-radiation area) A half-conductor layer of a power line or a resin composition for a jacket.

Also, the crosslinking agent may be 1,1- (tert-butylperoxy) -3,3,5-trimethylcyclohexane (TMC), 1,1- Butyl-4,4- (bis-butylperoxy) valerate (TVP), dicumylperoxide (DCP), 1,1-bis Butylperoxy-diisopropylbenzene (BPPB), benzoylperoxide (BPO), 2,5-dimethyl-2,5-di-tert-butylperoxy- 2,5-dimethyl-2,5-di-t-butylperoxyhexane (25B), t-butylperoxybenzoate (Z), ditertiary- Di-t-butylperoxide (DTBP) and 2,5-dimethyl-2,5-di-tert-butylperoxylhexane (2,5-dimethyl- (Non-Class 1E, Non-Radiation Zone) of a nuclear power plant, characterized in that it is at least one member selected from the group consisting of To provide a resin composition.

Also, the carbon black has a particle diameter of 10 to 100 nm, and provides a resin composition for a semiconductive layer or a jacket of a non-class 1E (non-radiation area) power line of a nuclear power plant.

The processing aid is at least one selected from the group consisting of polyethylene wax, paraffin wax, paraffin oil, organic silicone, fatty acid ester compound, fatty acid amide compound, fatty acid alcohol, fatty acid, zinc stearate, magnesium stearate and calcium stearate (Non-class 1E, non-radiation area) power line of a nuclear power plant, which is made of a non-conductive material.

In order to solve the above-mentioned problems, the present invention provides a thermoplastic resin composition comprising 40 to 60 parts by weight of an ethylene vinyl acetate copolymer (EVA) And 40 to 60 parts by weight of low density polyethylene (LDPE) to prepare a blend composition; Based on 100 parts by weight of the blend composition, 90 to 130 parts by weight of a flame retardant; 2 to 6 parts by weight of an antioxidant; 3 to 7 parts by weight of carbon black; And 3 to 7 parts by weight of a processing aid to the blend composition and melt mixing at a temperature of 100 to 130 캜; Stabilizing the melt-mixed composition at room temperature for 12 to 36 hours; And a step of adding 3 to 7 parts by weight of a crosslinking agent to 100 parts by weight of the blend composition to the stabilized composition and performing a crosslinking treatment at a temperature of 150 to 200 DEG C for 5 to 30 minutes. 1E, non-radiation area), a method for producing a resin composition for a semiconductive layer or a jacket of a power line.

According to the present invention, by combining ethylene vinyl acetate copolymer and low density polyethylene as base resins with specific additives such as flame retardant, antioxidant, crosslinking agent, carbon black, processing aid, etc., Non-radiation area) When used as a semiconductive layer or a jacket for a power line, the heat resistance and radiation resistance of the power line are remarkably improved, and a resin composition excellent in long-term longevity can be provided.

Also, it is possible to provide a method for efficiently producing a resin composition which is excellent in heat resistance, radiation resistance and long-term shelf life by a simple method by eliminating the conventional solution mixing method and performing melt mixing and proper crosslinking treatment.

FIG. 1 is a graph showing the results of measurement of oxidation induction time data according to ASTM 3895 by performing acceleration thermal deterioration after irradiation of radiation of 10 Mrad and 50 Mrad to the resin composition prepared according to Example 1,
2 is a graph showing the results of measurement of oxidation induction time data according to ASTM 3895 by performing acceleration thermal deterioration after irradiating radiation of 10 Mrad and 50 Mrad to the resin composition prepared according to Example 2,
3 is a graph showing the results of measurement of oxidation induction time data according to ASTM 3895 by performing acceleration thermal deterioration after irradiating the resin composition prepared according to Comparative Example 1 with radiation of 10 Mrad and 50 Mrad,
4 is a graph showing the results of measurement of oxidation induction time data according to ASTM 3895 by performing acceleration thermal deterioration after irradiating the resin composition prepared according to Comparative Example 2 with radiation of 10 Mrad and 50 Mrad,
FIG. 5 is a graph showing the results of life evaluation of a resin composition prepared according to Example 1 through a 50% elongation test after completion of an accelerated thermal deterioration and stabilization,
6 is a graph showing the results of life evaluation of the resin composition prepared according to Example 2 after completion of the accelerated thermal deterioration and stabilization steps and a 50% elongation test,
FIG. 7 is a graph showing the result of performing the life evaluation through the 50% elongation test after completion of the accelerated thermal deterioration and stabilization for the resin composition prepared according to Comparative Example 1,
FIG. 8 is a graph showing the results of life evaluation of a resin composition prepared according to Comparative Example 2 after completion of accelerated thermal deterioration and stabilization, and then an elongation of 50%.

Hereinafter, preferred embodiments of the present invention will be described in detail. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Throughout the specification, when an element is referred to as "including " an element, it means that it can include other elements, not excluding other elements, unless specifically stated otherwise.

The present inventors have found that ethylene vinyl acetate copolymer (hereinafter referred to as EVA), which is mainly used in a resin composition for use as a semiconductive layer or a jacket for a non-safety class (Non Class 1E, non-radiation area) power line of a nuclear power plant, The EVA resin composition of the optimum combination which can meet the recent long-term service life requirement with improved heat resistance and radiation resistance can be easily obtained As a result of intensive researches on manufacturing methods, it has been found that the present invention can be solved by melt-mixing the base resin made of EVA and low-density polyethylene (hereinafter referred to as "LDPE") having a specific composition with an optimal amount of a specific additive And led to the present invention.

Accordingly, the present invention provides a resin composition comprising: 40 to 60 parts by weight of an ethylene vinyl acetate copolymer (EVA); And 40 to 60 parts by weight of low density polyethylene (LDPE); 90 to 130 parts by weight of a flame retardant; 2 to 6 parts by weight of an antioxidant; 3 to 7 parts by weight of a crosslinking agent; 3 to 7 parts by weight of carbon black; (Non-Class 1E, non-radiation area) power line comprising 3 to 7 parts by weight of an inorganic filler and 3 to 7 parts by weight of a processing aid. First, components constituting the resin composition according to the present invention will be described in detail.

The base resin of the resin composition for a semiconductive layer or jacket of a non-safety grade power line of a nuclear power plant according to the present invention is composed of EVA and LDPE.

Although EVA has excellent mechanical strength and low cost, it is mainly used as a material for the whole layer of a power line of a nuclear power plant. However, it has a disadvantage in that heat resistance and radiation resistance are lowered. Therefore, the present invention adopts LDPE as a component blended in EVA The EVA and the LDPE are contained in an amount of 40 to 60 parts by weight, respectively, in order to improve the long-term durability and the heat resistance and radiation resistance of the same or higher than those of the EVA and LDPE.

In the present invention, the EVA requires an appropriate vinyl acetate content and a melt index for uniform blending with the LDPE, which is another base resin, and for improving the dispersibility of additives to be added afterward. Here, it is preferable that the melt index of EVA decreases as the vinyl acetate content increases. For example, in the present invention, EVA having a vinyl acetate content of 10 to 25 mol% and a melt index (ASTM 1238, 190 DEG C, 2.16 kgf) of 4 to 8 g / 10 min or a vinyl acetate content of 20 to 35 mol% EVA having a melt index (ASTM 1238, 190 캜, 2.16 kgf) of 1 to 6 g / 10 min can be used. EVA having a vinyl acetate content of 20 to 35 mol% and a melt index (ASTM 1238, 190 DEG C, 2.16 kgf) of 1 to 6 g / 10 min may be used.

In consideration of blending of the above-mentioned desirable physical properties with EVA, the LDPE preferably has a density of 0.915 to 0.925 g / cm 3 and a melt index (190 ° C, 2.16 kg) of 6 to 10 g / 10 min.

In the present invention, the flame retardant has a relatively high content with respect to the base resin so that the flame retardant imparts not only the flame retardancy but also the overall physical property balance and mechanical reinforcement effect when used in a semiconductive layer or a jacket of a power line of the resin composition to be finally produced. Accordingly, the flame retardant may be included in an amount of 90 to 130 parts by weight based on 100 parts by weight of the base resin. When the content is less than 90 parts by weight, flame retardancy imparting effect and physical property balance may be insufficient. The mechanical properties such as tensile strength and elongation may be deteriorated. Examples of the flame retardant include metal hydroxides such as magnesium hydroxide and aluminum hydroxide, talc and the like, but preferably vinyl silane, fatty acid, aminosilane and the like for improving compatibility with the base resin Surface treated metal hydroxides can be used.

In the present invention, the antioxidant is applied to a semi-conductor layer or a jacket of a non-safety grade (Non-Class 1E, non-radiation area) power line of a resin composition to be finally produced so as not to cause excessive oxidation deformation It is necessary not only to suppress the crosslinking reaction by the crosslinking agent described later but also to withstand the high temperature during the crosslinking reaction and to ensure that the antioxidant of a certain kind is contained in an optimal amount It is important to include. Therefore, in the present invention, a primary antioxidant that inhibits the generation of unstable free radicals generated by oxidation or makes a free radical to a stable form, and hydroperoxides that are formed by combining unstable free radicals with oxygen it is preferable to use a combination of a first antioxidant and a second antioxidant to prevent the generation of another unstable free radical which may be caused by the oxidation of hydroperoxide, 1 part by weight to 3 parts by weight may be used in combination. If the content of the antioxidant is less than 1 part by weight, the antioxidant power of the final resin composition may be weakened, and the heat resistance of the composition may be deteriorated. If the content of the antioxidant exceeds 3 parts by weight, And the antioxidant may be transferred to the surface of the wire by an excessive amount, so that the appearance may not be good.

The primary antioxidant may be a phenol-based or amine-based antioxidant commonly used in the art to which the present invention pertains, preferably 2,6-di-tertiary-butyl-4-methylphenol (2 , 6-di-t-butyl-4-methylphenol), tetrakis [methylene-3- (3,5-di- tert- butyl-4-hydroxyphenyl) propionate] methane - (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane, 2,2-methylenebis (4-methyl -6-t-butylphenol), octadecyl-3,5-di-t-butyl-4-hydroxyhydrocinnamate .

The secondary antioxidant may be a phosphorus-based or thio-based antioxidant commonly used in the art to which the present invention pertains, preferably tris (2,4-di-tertiary-butylphenyl) phosphite (2,4-di-t-butylphenyl) phosphite, bis (2,4-di-tert-butyl) pentaerythritol diphosphite, bis Alkylester phosphite and the like can be used.

In the present invention, the cross-linking agent is used to improve the crosslinking property of the base resin blended and to improve dispersibility of the additive, thereby contributing to the improvement of the longevity of the power line when applied to a semiconductive layer or a jacket. And 3 to 7 parts by weight based on 100 parts by weight of the resin. If the content of the crosslinking agent is less than 3 parts by weight, the crosslinking may not be sufficiently performed, and the physical properties of the final product may be deteriorated. If the content of the crosslinking agent is more than 7 parts by weight, Foreign matter may be observed on the product surface.

In consideration of the crosslinking property and compatibility of the base resin, the crosslinking agent is preferably 1,1- (tert-butylperoxy) -3,3,5-trimethylcyclohexane (1,1- , 3,5-trimethylcyclohexane (TMC), n-butyl-4,4- (bis-butyl peroxy) valerate (TVP), dicumyl peroxide dicumylperoxide (DCP), 1,1-bis (tert-butylperoxy) -diisopropylbenzene (BPPB), benzoylperoxide (BPO) 2,5-dimethyl-2,5-di-t-butylperoxyhexane (25B), tert-butylperoxybenzoate (t- butylperoxybenzoate (Z), di-t-butylperoxide (DTBP), 2,5-dimethyl-2,5-di-tert- butylperoxylhexane , 5-di-t-butylperoxylhexane, Hexyne-3) and the like are preferably used, but are not limited thereto.

In the present invention, the carbon black is added not only to provide an antistatic function but also to prevent weathering deterioration when applied to a power line for a resin composition. In the present invention, 3 to 7 parts by weight of the carbon black is used relative to 100 parts by weight of the base resin . When the carbon black content is less than 3 parts by weight, antistatic function and weather resistance deterioration preventing function may not be sufficient. If the carbon black content is more than 7 parts by weight, over current may cause a problem when applied by power line.

The carbon black preferably has a particle diameter of 10 to 100 nm. If the particle diameter is less than 10 nm, it may be difficult to uniformly disperse the resin composition during the production of the resin composition by the melt mixing method. It may be difficult to incorporate in a desirable amount.

In the present invention, the processing aid is added to increase the moldability by appropriately reducing the hardness while maintaining the flowability of the composition in the production of the resin composition according to the present invention using the melt mixing method. In the present invention, Is used in an amount of 3 to 7 parts by weight based on 100 parts by weight. If the amount of the processing aid is less than 3 parts by weight, it may be difficult to expect an increase in moldability. If the amount exceeds 7 parts by weight, the surface of the final product may be deteriorated or the mechanical properties may deteriorate.

The processing aid is not particularly limited as long as it is capable of imparting the functions described above. Examples of the processing aid include polyethylene wax, paraffin wax, paraffin oil, organic silicone, fatty acid ester compound, fatty acid amide compound, fatty acid alcohol, fatty acid, Zinc, magnesium stearate, calcium stearate and the like.

The resin composition according to the present invention may further contain another additive depending on the purpose of use within the scope of the present invention. The additional additives may be added alone or in admixture of two or more in the range of generally used additives such as impact modifiers, heat stabilizers, mold release agents, nucleating agents, inorganic additives, ultraviolet stabilizers, dyes, pigments, May be added in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the composition.

The resin composition according to the present invention can be easily manufactured by applying the melt mixing method unlike the conventional solution mixing method. That is, the base resin may be blended and then melt-mixed with the additives other than the cross-linking agent under specific conditions to stabilize the composition for a certain period of time, and then the cross-linking agent may be added thereto.

Specifically, 40 to 60 parts by weight of EVA; And 40 to 60 parts by weight of LDPE to prepare a blend composition; Based on 100 parts by weight of the blend composition, 90 to 130 parts by weight of a flame retardant; 2 to 6 parts by weight of an antioxidant; 3 to 7 parts by weight of carbon black; And 3 to 7 parts by weight of a processing aid to the blend composition and melt mixing at a temperature of 100 to 130 캜, preferably 110 to 120 캜; Stabilizing the melt-mixed composition at room temperature for 12 to 36 hours; And 3 to 7 parts by weight of a crosslinking agent to 100 parts by weight of the above-mentioned blend composition. The mixture is pressed for 5 to 30 minutes, preferably 7 to 15 minutes at 150 to 200 DEG C, preferably 160 to 180 DEG C A resin composition applicable to a semiconductive layer or jacket of a non-class 1E (non-radiation area) power line of a nuclear power plant can be manufactured through the step of crosslinking. Here, considering the preferable composition of the present invention, it may be difficult to uniformly mix and disperse the additive at a temperature outside the melt-mixing temperature range, and when the stabilization step is not performed, sufficient crosslinking properties are hardly exhibited in the subsequent cross- At a temperature outside the press temperature range, crosslinking may be insufficient or moldability may be deteriorated.

Hereinafter, a specific embodiment of the present invention will be described.

Example  One

50 parts by weight of an EVA having a vinyl acetate content of 15 to 20 mol% and a melt index (ASTM 1238, 190 DEG C, 2.16 kgf) of 6 g / 10 min and a melt index (ASTM 1238, 190 DEG C, 2.16 And 50 parts by weight of LDPE having a weight average molecular weight of 8 g / 10 min were blended to prepare a blend composition. 100 parts by weight of the blend composition was blended with 100 parts by weight of magnesium hydroxide as a flame retardant and 2,6- , 2 parts by weight of butyl-4-methylphenol, 2 parts by weight of tris (2,4-di-tertiary-butylphenyl) phosphite as a secondary antioxidant, 5 parts by weight of carbon black and 5 parts by weight of polyethylene wax as a processing aid Added to the above-mentioned blend composition, and melt-mixed at a temperature of 110 to 120 ° C. Thereafter, the melt-mixed composition was allowed to stand for 24 hours at room temperature to be stabilized. To the stabilized composition, 100 parts by weight of the blend composition was mixed with 1,1- (tertiarybutylperoxy) -3,3,5 -Trimethylcyclohexane (5 parts by weight) was added thereto, and the mixture was subjected to a crosslinking treatment for 10 minutes in a press at a temperature of 170 to 180 DEG C to prepare a polyolefin resin composition.

Example  2

A resin composition was prepared in the same manner as in Example 1, except that EVA having a vinyl acetate content of 25 to 30 mol% and a melt index (ASTM 1238, 190 DEG C, 2.16 kgf) of 3 g / 10 min was used in Example 1 Respectively.

Comparative Example  One

A resin composition was prepared in the same manner as in Example 1, except that 100 parts by weight of EVA except for LDPE was used.

Comparative Example  2

A resin composition was prepared in the same manner as in Example 1 except that 100 parts by weight of EVA except for LDPE was used.

The composition (unit: parts by weight) of the resin composition prepared according to the above Examples and Comparative Examples is shown in Table 1 below.

Test Example

In order to evaluate the longevity of the resin composition according to the present invention when applied to a semi-conductor layer or a jacket of a non-safety grade power line of a nuclear power plant, the resin compositions prepared according to the above Examples and Comparative Examples were subjected to radiation degradation, The induction time, elongation 50% test was performed. First, accelerated thermal degradation was performed after irradiating the resin composition with radiation of 10 Mrad and 50 Mrad. In order to perform accelerated thermal degradation, an activation energy factor is required, so it was calculated by the oxidation induction time test. The oxidation induction time was measured in accordance with ASTM 3895, and the measurement temperature was measured using Al Pan at 10 ° C / min in four temperature groups. The resin compositions prepared according to Examples 1 and 2 and Comparative Examples 1 and 2 The results are shown in Figs. 1 to 4, respectively. The activation energy was calculated by ASTM 2070 using the measured oxidation induction time data and the results are shown in Table 2 below.

As shown in Table 2, the activation energy of the resin composition (Example 2) using EVA 2 and LDPE together as the base resin is the most active energy for accelerated thermal degradation as a very important value for the life evaluation. Respectively.

Next, as described above, the life evaluation of the power line of the nuclear power plant is performed by calculating the activation energy of the resin composition by the oxidation induction time test and then determining the correlation between the accelerated thermal deterioration temperature and the accelerated thermal deterioration time when the activation energy is determined Can be predicted by determining the accelerated thermal degradation temperature and time according to the IEEE standard using the Arrhenius equation according to the following equation (1). The resin compositions after completion of the accelerated thermal annealing were subjected to a stabilization step at room temperature for 24 hours and then subjected to a life evaluation test by an elongation test of 50%. The resin compositions prepared according to Examples 1 and 2 and Comparative Examples 1 and 2 The results are shown in Figs. 5 to 8 and Table 3, respectively.

(Where, t _SER is the operating time, t _AG is accelerated thermal degradation time, φ is the activation energy, T _SER is the normal operating temperature, T _AG is accelerated thermal degradation temperature, K is Boltzmann's constant (8.617 × 10 in a normal temperature ^{- 5} eV / K))

Referring to Table 3, it can be seen that the resin composition (Example 2) using EVA 2 and LDPE together as a base resin has a lifetime of 60 years or more at 50 Mrad. Generally, when a polymer is exposed to radiation, a decomposition reaction and a cross-linking reaction occur. In the case of Example 2, the cross-linking reaction is predominantly exhibited. Accordingly, it can be confirmed that the resin composition according to the present invention can be very usefully used as a semiconductive layer or jacket material of a non-safety grade power line of a nuclear power plant.

The preferred embodiments of the present invention have been described in detail above. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing detailed description, and all changes or modifications derived from the meaning, range, and equivalence of the claims are included in the scope of the present invention Should be interpreted.

Claims (11)

40 to 60 parts by weight of an ethylene vinyl acetate copolymer (EVA); And 40 to 60 parts by weight of low density polyethylene (LDPE); 90 to 130 parts by weight of a flame retardant; 2 to 6 parts by weight of an antioxidant; 3 to 7 parts by weight of a crosslinking agent; 3 to 7 parts by weight of carbon black; And 3 to 7 parts by weight of a processing aid, wherein the resin composition is a melt-
The ethylene vinyl acetate copolymer has a vinyl acetate component content of 20 to 35 mol% and a melt index (ASTM 1238, 190 DEG C, 2.16 kgf) of 1 to 6 g / 10 min,
The resin composition is a resin composition for a semiconductive or jacket of a non-class 1E (non-radiation area) power line of a nuclear power plant characterized by having a life span of 60 years or more evaluated by the following method.
[Life Evaluation Method]
The correlation between the accelerated thermal degradation temperature and the accelerated thermal degradation time when the activation energy was determined after the activation energy of the resin composition irradiated with 50 Mrad was irradiated (according to ASTM 2070) by the oxidation induction time test (according to ASTM 3895) The accelerated thermal deterioration temperature and time were determined according to the IEEE standard using the Arrhenius equation according to the following equation (1). The resin composition after accelerated thermo-thermal decomposition was stabilized at room temperature for 24 hours and then subjected to an elongation of 50 % The life test is carried out through the test.
[Equation 1]

(Where, t _SER is the operating time, t _AG is accelerated thermal degradation time, φ is the activation energy, T _SER is the normal operating temperature, T _AG is accelerated thermal degradation temperature, K is Boltzmann's constant (8.617 × 10 in a normal temperature ^{- 5} eV / K)) delete The method according to claim 1,
Wherein the low density polyethylene has a density of 0.915 to 0.925 g / cm 3 and a melt index (ASTM 1238, 190 캜, 2.16 kgf) of 6 to 10 g / 10 min. A resin composition for a half conductor or jacket of a power line. The method according to claim 1,
Wherein the flame retardant is at least one selected from the group consisting of magnesium hydroxide, aluminum hydroxide and talc. The resin composition for a semiconductive layer or jacket of a non-class 1E (non-radiation area) power line of a nuclear power plant. The method according to claim 1,
Wherein the antioxidant is composed of 1 to 3 parts by weight of a primary antioxidant and 1 to 3 parts by weight of a secondary antioxidant. The non-safety grade (Non-Class 1E, non-radiation area) Composition. 6. The method of claim 5,
The primary antioxidant may be 2,6-di-t-butyl-4-methylphenol, tetrakis [methylene-3- (Tert-butyl-4-hydroxyphenyl) propionate] methane (Tetrakis [methylene-3- (4-methyl-6-t-butylphenol) and octadecyl-3,5-di-tertiary-butyl-4-hydroxy (Non-Class 1E, non-radiation area) power line, which is at least one selected from the group consisting of octadecyl-3,5-di-t-butyl-4-hydroxyhydrocinnamate A resin composition for a semiconductive or jacket. 6. The method of claim 5,
The second antioxidant may be tris (2,4-di-t-butylphenyl) phosphite, bis (2,4-di-tert-butylphenyl) phosphite, ) Non-safety grade (Non Class 1E) nuclear power plant characterized in that it is at least one selected from the group consisting of bis (2,4-di-t-butyl) pentaerythritol diphosphite and alkylester phosphite. , Non-radiation area) Half conductor layer of power line or resin composition for jacket. The method according to claim 1,
The crosslinking agent is selected from the group consisting of 1,1- (tert-butylperoxy) -3,3,5-trimethylcyclohexane (TMC), 1,1- 4,4- (bis-butylperoxy) valerate (TVP), dicumylperoxide (DCP), 1,1-bis -Butylperoxy-diisopropylbenzene (BPPB), benzoylperoxide (BPO), 2,5-dimethyl-2,5-di-tertiary 2,5-dimethyl-2,5-di-t-butylperoxyhexane (25B), tert-butylperoxybenzoate (Z), ditertiary-butylperoxide di-t-butylperoxide (DTBP) and 2,5-dimethyl-2,5-di-t-butylperoxylhexane (Hexyne-3) (Non-class 1E, non-radiation area) power line of a nuclear power plant characterized by at least one member selected from the group consisting of Composition. The method according to claim 1,
Wherein the carbon black has a particle diameter of 10 to 100 nm. The resin composition for a semiconductive or jacket of a non-class 1E (non-radiation area) power line of a nuclear power plant. The method according to claim 1,
Wherein the processing aid is at least one selected from the group consisting of polyethylene wax, paraffin wax, paraffin oil, organic silicone, fatty acid ester compound, fatty acid amide compound, fatty acid alcohol, fatty acid, zinc stearate, magnesium stearate and calcium stearate Non-safety grade of nuclear power plant (Non Class 1E, non-radiation area) Half conductor layer of power line or resin composition for jacket. 40 to 60 parts by weight of an ethylene vinyl acetate copolymer (EVA); And 40 to 60 parts by weight of low density polyethylene (LDPE) to prepare a blend composition;
Based on 100 parts by weight of the blend composition, 90 to 130 parts by weight of a flame retardant; 2 to 6 parts by weight of an antioxidant; 3 to 7 parts by weight of carbon black; And 3 to 7 parts by weight of a processing aid to the blend composition and melt mixing at a temperature of 100 to 130 캜;
Stabilizing the melt-mixed composition at room temperature for 12 to 36 hours; And
Adding 3 to 7 parts by weight of a crosslinking agent to 100 parts by weight of the stabilized composition, and crosslinking the mixture at a pressing temperature of 150 to 200 DEG C for 5 to 30 minutes;
Wherein the resin composition is a resin composition,
The ethylene vinyl acetate copolymer has a vinyl acetate component content of 20 to 35 mol% and a melt index (ASTM 1238, 190 DEG C, 2.16 kgf) of 1 to 6 g / 10 min,
Wherein the resin composition has a life span of 60 years or more evaluated according to the following method: (1) A method for producing a resin composition for a semiconductive or jacket of a non-class 1E (non-radiation area) power line.
[Life Evaluation Method]
The correlation between the accelerated thermal degradation temperature and the accelerated thermal degradation time when the activation energy was determined after the activation energy of the resin composition irradiated with 50 Mrad was irradiated (according to ASTM 2070) by the oxidation induction time test (according to ASTM 3895) The accelerated thermal deterioration temperature and time were determined according to the IEEE standard using the Arrhenius equation according to the following equation (1). The resin composition after accelerated thermo-thermal decomposition was stabilized at room temperature for 24 hours and then subjected to an elongation of 50 % The life test is carried out through the test.
[Equation 1]

(Where, t _SER is the operating time, t _AG is accelerated thermal degradation time, φ is the activation energy, T _SER is the normal operating temperature, T _AG is accelerated thermal degradation temperature, K is Boltzmann's constant (8.617 × 10 in a normal temperature ^{- 5} eV / K))

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