JPH09188785A - Cross-linkable resin composition, power cable and power cable connection using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the above composition useful as an insulator layer of an insulated power cable, free from admixture of foreign material, low in water content after cross-linking, few in number of microvoids, excellent in electric insulating characteristics, by blending an olefin-based resin with an organic peroxide and a specific antioxidant. SOLUTION: This composition is obtained by blending (A) an olefin-based resin with (B) an organic peroxide such as dicumyl peroxide and (C) an antioxidant which contains bis[2-methyl-4-(3-n-12C or 14C alkylthiopropionyloxy)-5-t- butylphenyl]sulfide (C1 ) and adjusted to <=1.5 acidity e.g. a mixture of 50-90wt.% of the component C1 and 50-10wt.% of (3-methyl-6-t-butylphenyl) [2-methyl-4-(3-n-12C or 14C alkylthiopropionyloxy)-5-t-butylphenyl]sulfide} as essential imgredents.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crosslinkable resin composition particularly useful for forming an insulating layer of a power cable, and to a power cable and a power cable connection using the same.

[0002]

2. Description of the Related Art Crosslinked olefin resin-insulated power cables, which have been widely used for high-voltage power transmission, usually have a cable core in which an inner semiconductive layer, an insulator layer, and an outer semiconductive layer are provided in this order on the outer periphery of a conductor. It has a basic structure in which a metal shielding layer and an anticorrosion sheath layer are provided on the outside with a pressing tape or the like interposed as necessary. The above-mentioned inner semiconductive layer, insulator layer, and outer semiconductive layer are, for example, extruded and coated on the outer circumference of a conductor with a resin composition based on an olefin resin containing a crosslinking agent and an antioxidant, and then the whole is added. It is formed by crosslinking the olefin resin by heating under pressure.

The interconnection of such a crosslinked olefin resin insulated power cable is usually performed as follows. First, the connection terminals of the two power cables to be connected are subjected to step stripping according to a conventional method to expose the outer peripheral surfaces of the conductor, the inner semiconductive layer, the insulator layer, the outer semiconductive layer, and the like. Then, the end surfaces of the conductors of the electric power cables are butted against each other, and the outside of the butted portion is crimped with a sleeve for conductor connection. Then, an inner semiconductive layer, an insulating layer (usually referred to as a reinforcing insulating layer), and an outer semiconductive layer are sequentially formed outside the conductor connecting portion.

The above-mentioned reinforcing insulator is manufactured by the tape molding method,
It is formed by either an extrusion molding method using a mold or a method of attaching a reinforcing insulator block preformed in a factory in the field. The tape molding method is a method in which an insulating tape made of a crosslinkable resin composition is wound, and the wound layer is heated under pressure to perform a crosslinking treatment, and the extrusion molding method is a method of forming a connecting portion at the time of forming a reinforcing insulator. Is a method in which a predetermined mold is arranged outside, the crosslinkable resin composition is injected into the mold, and the mixture is crosslinked by heating under pressure to form an insulating layer. In addition, the method using the reinforced insulator block is
It consists of a separable tubular insulator block body made of a crosslinkable resin composition and an internal electrode made of semi-conductive polyolefin etc. built into its inner peripheral surface, and fits the cable insulator at the end face. This is a method in which an insulator block having a cylindrical tapered portion is assembled on the conductor connecting portion on site and then heated under pressure to crosslink the insulator (see Japanese Patent Laid-Open No. 4-145823). The inner semiconductive layer and the outer semiconductive layer of the connecting portion are usually formed by using a semiconductive heat-shrinkable tube or winding a semiconductive tape.

As a material for forming the crosslinked olefin resin-insulated electric power cable and the insulating material of the connecting portion as described above, an olefin resin containing low-density polyethylene as a main component is usually used as a base resin, and dicumyl is added to the base resin. Organic peroxides such as peroxides (hereinafter also referred to as crosslinking agents), 4,4
A resin composition containing an antioxidant such as'-thiobis (3-methyl-6-t-butylphenol) is used.

[0006]

It is obtained by crosslinking a crosslinkable resin composition containing an olefin resin as a main component, an organic peroxide, an antioxidant and, if necessary, other additives. When the insulation layers of power cables, insulation layers of power cable connections, etc. (hereinafter collectively referred to simply as insulation layers) are exposed to the harsh conditions associated with high voltage, they become It is known that a slight amount of foreign matter, voids, water, etc. cause the electrical characteristics to be significantly reduced.

In order to prevent foreign matter from entering the insulating layer,
Base resin, antioxidant, organic peroxide,
It is necessary to reduce the amount of foreign substances mixed in other additives as much as possible, and therefore, a method of filtering one or a mixture of two or more of these raw materials in a molten state using a screen mesh having a fine passage diameter is used. Has been adopted. As a specific example of this method, there is a method in which a crosslinking agent and an antioxidant are liquefied and then filtered. In this method, it is necessary to use at least one of a crosslinking agent and an antioxidant that is liquid at room temperature or becomes liquid when heated.

Dicumyl peroxide, which is a commonly used cross-linking agent, has a melting point of about 40 ° C. and can be liquefied by heating. On the other hand, 4,4'-thiobis (3-methyl-6-t-), which is a commonly used antioxidant, is used.
Butylphenol) has a melting point of 155 ° C. or higher and is difficult to liquefy. Further, 4,4′-thiobis (3-methyl-6-t) with respect to liquefied dicumyl peroxide
-Butylphenol) has a low solubility and the required amount of 4,4
'-Thiobis (3-methyl-6-t-butylphenol) cannot be blended. On the other hand, bis [2] is used as an antioxidant that is liquid at room temperature and is easy to mix uniformly with resin.
- methyl-4-{3-n-alkyl (C ₁₂ or C ₁₄₎
Thiopropionyloxy} -5-t-butylphenyl]
There is a trade name ADEKA STAB AO23 (manufactured by Asahi Denka Kogyo KK) containing sulfide as a main component. Since this antioxidant is liquid at room temperature, it is also suitable for the above-mentioned filtration method.

The inventors of the present invention aimed to adopt the above-mentioned ADEKA STAB AO23, which is also suitable for foreign matter removal, as an antioxidant, and used a crosslinkable resin composition containing the same to enhance the reinforced insulation of cable connection parts. When a body layer was formed and investigated, it was found that the obtained reinforced insulator had a moisture content higher than that of the case where 4,4′-thiobis (3-methyl-6-t-butylphenol) was used as an antioxidant. It was confirmed that more microvoids due to the generation were generated.

Moisture is generated in the insulating layer due to the further thermal decomposition (secondary decomposition) of alcohols formed by the decomposition of the organic peroxide in the step of crosslinking the base resin. With a water content of 250 ppm or less, the generation of microvoids is extremely small, and the electrical characteristics of the power cable are not deteriorated. However, the water content is 250 pp
If it exceeds m, the generation of micro voids cannot be ignored,
It is known to lead to deterioration of electrical characteristics. Especially,
Cross-linking of the reinforcing insulation of the connection part requires a long time of several hours or more compared to heat-cross-linking of the insulation layer of the cable body, so the decomposition residue of the cross-linking agent is more likely to undergo secondary decomposition. It is high, and the amount of water in the insulator tends to increase.

Therefore, an object of the present invention is bis [2-methyl-], which is a liquid antioxidant that facilitates the removal of foreign substances.
Even if an antioxidant containing 4- {3-n-alkyl (C ₁₂ or C ₁₄ ) thiopropionyloxy} -5-t-butylphenyl] sulfide as a main component is blended, water generated after the crosslinking treatment is generated. To provide a crosslinkable resin composition capable of suppressing the amount as low as possible, and to provide a power cable excellent in electrical characteristics in which the crosslinkable resin composition is applied to an insulator layer, and a power cable connecting portion. is there.

[0012]

Means for Solving the Problems Based on the above-mentioned finding that the amount of water produced varies depending on the type of antioxidant even when the crosslinking treatment is carried out under the same conditions, the inventors of the present invention described above. 2-methyl-4- {3-n-alkyl (C ₁₂ or C
₁₄ ) In a crosslinked insulator that occurs when using ADEKA STAB AO23 (manufactured by Asahi Denka Kogyo Co., Ltd.) under the trade name containing thiopropionyloxy} -5-t-butylphenyl] sulfide (hereinafter also referred to as compound A) as a main component As a result of intensive studies on the factor of increasing the amount of water generation, the inventors have found that the acid value of the antioxidant is closely related to the amount of water generation, and have completed the present invention.

That is, in order to achieve the above object, in the invention according to claim 1 of the present invention (hereinafter, also referred to as the first invention), an olefin resin, an organic peroxide, and bis [2-methyl] are used. -4- {3-n-alkyl (C ₁₂ or C
₁₄ ) A crosslinkable resin containing thiopropionyloxy} -5-t-butylphenyl] sulfide as a main component and an antioxidant having an acid value adjusted to 1.5 or less as an essential component. A composition is provided.

In the invention according to claim 2 of the present invention (hereinafter, also referred to as the second invention), in a power cable having an insulating layer made of a crosslinked olefin resin, the insulating layer is an olefin resin. And organic peroxide and bis [2-
Methyl-4-{3-n-alkyl (C ₁₂ or C ₁₄₎ thio propionyloxy} -5-t-butylphenyl] containing sulfide as a main component, an acid value of antioxidant adjusted to 1.5 or less There is provided a power cable comprising a cross-linked resin composition in which and are mixed as essential components are cross-linked.

Further, in the invention according to claim 3 of the present invention (hereinafter, also referred to as the third invention), the crosslinked olefin resin is provided outside the conductor joint of the insulated power cable made of the crosslinked olefin resin and near the conductor joint. In an electric power cable joint provided with an insulating layer made of olefin, the insulating layer includes an olefin resin, an organic peroxide, and bis [2-methyl-4-
An essential component containing {3-n-alkyl (C ₁₂ or C ₁₄ ) thiopropionyloxy} -5-t-butylphenyl] sulfide as a main component and an antioxidant having an acid value adjusted to 1.5 or less. There is provided a power cable connecting part characterized by comprising a cross-linked cross-linkable resin composition blended as above.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The olefin-based resin serving as the base resin in the crosslinkable resin composition of the present invention refers to polyethylene and a copolymer containing ethylene as a main component. Specific examples of polyethylene include
Low density polyethylene, ultra low density polyethylene, linear low density polyethylene and the like can be mentioned.
Ethylene-propylene copolymer, ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, ethylene-
Examples thereof include styrene copolymers and ethylene-propylene-diene terpolymers. Especially preferred among these is low density polyethylene.

The crosslinkable resin composition according to the first aspect of the present invention comprises the above base resin and an organic peroxide and an antioxidant having an acid value adjusted to 1.5 or less. The organic peroxide functions as a cross-linking agent that cross-links the base resin forming the insulating layer of the power cable and the insulating layer of the power cable connecting portion. Specific examples of the organic peroxide that can be used in the present invention include dicumyl peroxide, m- (t-butylperoxyisopropyl) -isopropylbenzene,
p- (t-butylperoxyisopropyl) -isopropylbenzene, t-butylcumyl peroxide, benzoyl peroxide, di-t-butyl peroxide,
2,5-Dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne, 1,3-bis (t-butylperoxy) Oxyisopropyl) benzene, t-butyl-hydroperoxide and the like. Of these, dicumyl peroxide is particularly preferable.

In the present invention, the antioxidant serves to prevent oxidative deterioration of the base resin, thermal decomposition, thermal coloring, contact deterioration due to heavy metals under severe conditions, and the like. In order to suppress the generation of water, which is the object of the present invention, it is necessary to use a compound containing Compound A as a main component as an antioxidant and having an acid value adjusted to 1.5 or less. Acid value is 1.5
The use of an antioxidant exceeding 5 is not preferable because a large amount of microvoids are generated in the insulating layer of the power cable, the insulating layer of the connecting portion of the power cable, and the like from the crosslinkable resin composition containing the antioxidant. In particular, when constructing the connection portion in the power cable, since the crosslinkable resin composition that constitutes the insulating layer of the power cable connection portion is heated to a high temperature for a long time to be crosslinked, moisture increases due to this heating and microvoids are generated. It causes the occurrence.

The acid value of the antioxidant containing the compound A as a main component is affected by a trace amount of the organic acid and / or the metal salt of the organic acid contained in the antioxidant. The antioxidant containing Compound A as a main component is shipped as it is contained in the product without separating a small amount of the raw material compound from the technical and economical viewpoints in the production. Furthermore, some of the raw material compounds contained in the product include those that cause the odor of the product, so a deodorant may be added to eliminate this odor. The deodorant is mainly a metal salt of an organic acid, and the metal salt of the organic acid is contained in the antioxidant of the product, which causes the acid value to increase.

Since it is technically and economically disadvantageous to prevent the antioxidant from containing these unreacted raw material compounds and deodorant, it is extremely disadvantageous. The acid value may be 1.5 or less, particularly preferably 1.0 or less, within a permissible range that does not adversely affect the electrical characteristics of the insulating layer.
In the present invention, the “acid value” of the antioxidant is JIS
Sample 1 means the value measured according to K-2501.
It means the number of mg of potassium hydroxide required to neutralize acidic substances such as free fatty acids contained in g. The larger this value is, the less preferable it is.

The antioxidant which can be used in the present invention essentially contains the compound A as a main component, and among them, bis [2-methyl-4- {3-n-alkyl (C ₁₂
Or C ₁₄ ) thiopropionyloxy} -5-t-butylphenyl] sulfide (compound A) as a main component,
[3-methyl -6-t-butyl-phenyl] [2-methyl-4-{3-n-alkyl (C ₁₂ or C ₁₄₎ thio propionyloxy} -5-t-butylphenyl] sulfide (hereinafter Compound B Particularly preferred is a mixture of Since the mixture of the compound A and the compound B is a liquid at room temperature, the foreign matter contained therein can be easily removed by filtration using a screen mesh with a fine passage diameter.

The ratio of the two in the mixture is the compound A
It is particularly preferable to select 50 to 90% by weight of Compound B and 50 to 10% by weight of Compound B. If the proportion of the compound B in the mixture is too large, the number of radicalized phenolic hydroxyl groups becomes excessive, and a part thereof reacts with radicals of the organic peroxide to consume the organic peroxide, As a result, the inhibition of crosslinking of the base resin starts to occur, so that the proportion of the compound B is selected at 50% by weight or less. However, if the proportion of the compound B is too small, that is, if the amount of the compound A is too large, dissociation of the ester bond in the compound A does not proceed sufficiently, and after crosslinking, a large amount of the compound A that does not undergo graft polymerization with the base resin remains. As a result, when the obtained base resin cross-linked product is used as an insulating layer of a power cable, tan δ is increased under a high temperature and high electric field. Therefore, the ratio of the compound A is 90% by weight or less, Therefore, the proportion of the compound B is selected to be 10% by weight or more.

The antioxidants are compound A and compound B described above.
A mixture with and is particularly preferable, but these are the main components, and other antioxidants can be used together therewith. Examples of the antioxidant that can be used in combination include 4,4′-thiobis (3-methyl-6-t-butylphenol), dilaurylthiodipropionate, ditridecylthiodipropionate, tetrakis [methylene-3- (n-dodecylthio). ) Propionate] methane, tris (2,4-di-t-butylphenyl) phosphite and the like.

The crosslinkable resin composition according to the first aspect of the present invention is compounded with the above-mentioned organic peroxide and antioxidant as essential components. In addition to these, other additives may be added if necessary. It can be blended. Other additives that can be blended include lubricants, fillers, flame retardants, antistatic agents, copper damage inhibitors, and heat-bonding agents in types and amounts that do not affect the acid value. Specific examples of these additives include oleic acid amide, esyl acid amide, ethylene glycol monostearate, acetyl alcohol, and stearyl alcohol.

To prepare the crosslinkable resin composition according to the first aspect of the present invention, the base resin is weighed with an organic peroxide, an antioxidant and, if necessary, other additives, and dry blended. Alternatively, it is melt-kneaded and pelletized. On this occasion,
The base resin should be one that is manufactured by a method that does not allow fine foreign matter to be mixed, or that that is manufactured by melt-extruding with an extruder equipped with a screen mesh with a fine passage diameter to reduce fine foreign matter as much as possible. Preference is given to using. Similarly, the organic peroxide and the antioxidant are used after being melted and filtered through a screen mesh having a fine passage diameter to reduce fine foreign matters as much as possible. When manufacturing a power cable, a liquefied organic peroxide and an antioxidant are injected and kneaded into a molten base resin in an extruder to obtain a crosslinkable resin composition. Thus, an insulator layer can be formed on the outer periphery of the conductor by coextrusion with the inner semiconductive layer and the outer semiconductive layer.

The amounts of the organic peroxide and the antioxidant to be blended in the base resin are 0.5 to 10 parts by weight of the organic peroxide and 0 of the antioxidant with respect to 100 parts by weight of the olefin resin of the base. It is preferable to select in the range of 1 to 2 parts by weight. If the compounding amount of the organic peroxide is less than 0.5 part by weight, a sufficient crosslinking effect cannot be obtained, and if it exceeds 10 parts by weight, the degree of crosslinking proceeds too much and burning occurs. .
A particularly preferable blending amount of the organic peroxide is in the range of 1.5 to 3 parts by weight. If the compounding amount of the antioxidant is less than 0.1 part by weight, the effect of preventing oxidative deterioration, thermal decomposition and thermal coloring of the insulating layer is not sufficient, and if it exceeds 2 parts by weight, the crosslinking reaction is inhibited. Both are not preferable because they are easy and the degree of crosslinking of the insulating layer tends to be low.

In order to manufacture the power cable according to the second invention, the blended product or the pellet-like crosslinkable resin composition prepared by the above method is melt-kneaded by an extruder or made into a molten state in the extruder. Liquid liquefied organic peroxide and antioxidant are injected into a certain base resin, melted and kneaded, and simultaneously extruded with the inner semiconductive layer and outer semiconductive layer formed on the outer circumference of the conductor through a die attached to the end of the extruder. To form an insulator layer and then heat the layer in the crosslinking zone to crosslink the insulator layer. The heating temperature in the cross-linking zone varies depending on the type of base resin, the type and amount of organic peroxide, the type and amount of antioxidant, the type and amount of other additives, but is in the range of 200 to 280 ° C. You can choose.

The method of manufacturing the power cable connecting portion according to the third invention differs depending on its form. When forming the insulator, the insulating tape is manufactured by the extrusion molding method by the tape molding method, and the mold is manufactured by the extrusion molding method. It can be manufactured by the extrusion molding method used, and in the method using the reinforcing insulator block, it is also manufactured by the mold molding method. Whichever manufacturing method you use,
The crosslinkable resin composition of the first invention is used.

When forming the power cable connecting portion, it depends on the form of the connecting portion. For example, in the extrusion molding method, the end portion of the power cable is machined into a substantially conical shape, and then the end portions are made to face each other to make conductor connection. After forming the inner semiconductive layer, an extrusion-molded uncrosslinked insulator layer is formed. Then, by heating under pressure, the uncrosslinked insulator layer is crosslinked to obtain a power cable connection part. The heating temperature varies depending on the type of the base resin, the thickness of the insulating layer, the type and amount of the organic peroxide, the type and amount of the antioxidant, the type and amount of other additives, etc. 170-
It is selected in the range of 280, and the heating time varies depending on the heating temperature, but can be selected in the range of 5 hours to 20 hours.

[0030]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the examples described below. The acid value of the antioxidant used in the examples described below conforms to JIS K-2501, and a sample of 20 g is taken in 100 ml of isopropyl alcohol, and α-naphtholbenzein is used as an indicator,
It is measured by a method of neutralization titration with a 0.1 mol / liter potassium hydroxide / isopropyl alcohol solution.

[Examples 1 and 2, Comparative Examples 1 and 2] <Preparation of crosslinkable resin composition> The following organic peroxides and antioxidants were used in the proportions (parts by weight) shown in Table 1. Was weighed, the organic peroxide was heated to 60 ° C. and dissolved to form a liquid, and an antioxidant was mixed and dissolved in this, and the liquefied mixture was filtered through a screen mesh having a fine passage diameter. This liquefied mixture was blended with low density polyethylene (manufactured by Mitsubishi Chemical Corporation, density = 0.92, MI = 1.0) to obtain a pellet-like crosslinkable resin composition. In Comparative Example 2, a solid organic peroxide and an antioxidant were directly blended (dry-blended) with low-density polyethylene to obtain a pellet-shaped crosslinkable resin composition.

Organic peroxide a: Dicumyl peroxide (manufactured by Mitsui Petrochemicals, DCP) Organic peroxide a: t-butyl cumyl peroxide (manufactured by NOF Corporation, perbutyl C) Antioxidant C: Compound 20% by weight of B and 80% of compound A
A mixture with 10% by weight of which the acid value is 0.9 (manufactured by Asahi Denka Co., Ltd.) Antioxidant D: 20% by weight of compound B and 80% of compound A
Mixture with wt%, acid value of 2.8 (Adeka Stab AO23 manufactured by Asahi Denka Co., Ltd.) Antioxidant o: 4,4'-thiobis (3-methyl-6-
t-butylphenol) (Ouchi Shinko Chemical Co., Nocrac 300)

<Manufacturing and construction of power cable connection part> Bridge
Insulated power cable (275KV1400mm^Two ) End
After cutting into a substantially conical shape,
Face each other and make conductor connections to form an internal semi-conductive layer
After that, place it in the mold and mix the pellets in the proportions shown in Table-1.
The ket-shaped crosslinkable resin composition is kneaded and melted in an extruder.
After that, it is extruded and injected into the mold to form the power cable connection.
did. After removing the mold, mold the insulator and
Cover the circumference with a semi-conductive shrink tube and heat shrink it.
Covering the outer circumference of the connection part, and further gas barrier on the outer circumference
Layers and heating heaters are sequentially coated, and in the cross-linked tube,
240 ℃ temperature, gas pressure 8kg / cm^Two  10 o'clock under G condition
It was held for a while to crosslink the insulating layer of the connection part.

<Evaluation> 1. Test of electrical characteristics To the power cables having the connecting portions obtained in Examples 1 and 2 and Comparative Example 2, a 50 Hz AC current was applied at a voltage application step of 100 kV / 1 hour, and an AC long-term breakdown test was performed. The higher the breakdown voltage, the better the electrical characteristics. The test results are shown in Table 1. 2. Measurement of Water Content and Micro Voids With respect to the samples tested for the above electrical characteristics and the power cable obtained in Comparative Example 1, water content was measured by the method described below.
The microvoids were measured. A sample is taken from the insulating layer (middle layer) of the connection part to which the power cable is connected, the water content of the sample is quantified by the Karl Fischer method, and the inside of the sample is observed with a microscope of 400 times, The number of microvoids was measured. Table-Measurement results
No. 1.

[0035]

[Table 1]

The following is clear from Table-1. (1) Example 1 containing an antioxidant having an acid value of less than 1.5
Also, in Example 2, the water content is small and the number of microvoids generated is small. (2) On the other hand, in Comparative Example 1 in which the antioxidant having an acid value of more than 1.5 was mixed, the water content was large and the number of microvoids was large. (3) The antioxidants used in Examples 1 and 2 are
Since the mixture of the compound A and the compound B is liquid at room temperature, foreign matter is removed by filtration with a filter, and thus the insulated power cable of the product exhibits good electrical characteristics. (4) On the other hand, in Comparative Example 2 in which the antioxidant not filtered by the filter was blended, the electrical characteristics were low.

[0037]

Industrial Applicability As described above, the present invention has the following special advantageous effects, and its industrial utility value is extremely large. 1. Since the crosslinkable resin composition according to the first invention of the present invention contains an antioxidant having an acid value of less than 1.5, insulation of an insulated power cable obtained by crosslinking the crosslinkable resin composition. The body layer and the insulator layer of the insulated power cable connecting portion have a low water content and a small number of microvoids. 2. Compounds A and B that are liquid at room temperature as antioxidants
When the mixture of and is used, foreign matter is removed by filtration with a filter having fine pores, so that the insulated power cable and the connecting portion according to the present invention both exhibit excellent electrical characteristics. 3. The insulated power cable according to the second aspect of the present invention and the insulated power cable connecting portion according to the second aspect of the present invention exhibit the effect that the electrical characteristics do not change even when exposed to harsh conditions.

Claims (3)

[Claims] 1. An olefin resin, an organic peroxide,
Bis [2-methyl-4-{3-n-alkyl (C ₁₂ or C ₁₄₎ thio propionyloxy} -5-t-butylphenyl] containing sulfide as a main component, an acid number 1.
A crosslinkable resin composition comprising an antioxidant adjusted to 5 or less as an essential component. 2. A power cable having an insulating layer made of a cross-linked olefin resin, wherein the insulating layer comprises an olefin resin, an organic peroxide, and bis [2-methyl-4-].
An essential component containing {3-n-alkyl (C ₁₂ or C ₁₄ ) thiopropionyloxy} -5-t-butylphenyl] sulfide as a main component and an antioxidant having an acid value adjusted to 1.5 or less. An electric power cable comprising a cross-linked cross-linkable resin composition blended as above. 3. In a power cable joint, wherein an insulating layer made of a crosslinked olefin resin is provided outside a conductor joint of a crosslinked olefin resin insulated power cable and in the vicinity of the conductor joint, the insulator layer is an olefin. the system resin, an organic peroxide, bis [2-methyl-4-{3-n-alkyl (C ₁₂ or C ₁₄₎ thio propionyloxy} -5-t
-Butylphenyl] sulfide as a main component,
An electric power cable connecting part, which comprises a crosslinked resin composition in which an antioxidant having an acid value adjusted to 1.5 or less is blended as an essential component.