JP2000306433A - Insulating resin composition and electric wire and cable using it, and power cable connecting part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure high stability for a long time by adding an organic peroxide and a hindered phenolic compound to polyolefinic resin, and furthermore adding a compound having -SR group which is an alkyl group having the specified number of carbon atoms of -R and a hindered amine compound. SOLUTION: A compound having -SR group which is an alkyl group having 8 or more carbon atoms of -R and a hindered amine compound represented by the formula are added to polyolefinic resin. Preferably, the hindered amine has a molecular weight of 1500 or more and the adding amount is 0.05-2.0 pts.wt. to 100 pts.wt. polyolefin base resin, and poly[ 6-1,1,3,3-tetramethyl)amino-1,3,5- triazine 2,4-diyl} (2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene (2,2,6,6- tetramethyl-piperidyl)imino}] is listed. As the compound having -SR group, dimyristyl-3,3-thiodipropionate is listed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crosslinked polyolefin resin insulating composition for electric wires and cables excellent in long-term stability, and to an electric wire and cable coated with the resin composition and a connecting portion. .

[0002]

2. Description of the Related Art Conventionally, crosslinked polyolefin resins, particularly crosslinked polyethylene, have been widely used as electric insulating materials for electric wires and cables, in addition to oil-immersed paper. Crosslinked polyolefin resin insulated cables are oil-immersed paper insulated cables (O
F cable) is widely used instead of an OF cable because of its ease of maintenance and low power transmission loss. In recent years, the voltage of crosslinked polyolefin insulated cables has been increased, and the 500 kV class has been put into practical use. On the other hand, even in a line with a low operating voltage, a higher electric field is being promoted by reducing the insulation thickness, and the demand for withstand voltage performance of the insulator is becoming increasingly severe. Under such circumstances, it has been a problem of the crosslinked polyolefin insulated cable to simultaneously improve the initial and long-term withstand voltage performance of the insulator.

Factors that affect the initial and long-term stability of a crosslinked polyolefin resin insulating composition include foreign matter, voids, moisture, and protrusions at the interface of the semiconductive layer in the insulator. Regarding the initial performance, material management without foreign matter mixing,
The initial objective has been achieved by adopting a dry crosslinking method and reducing the number of protrusion nuclei by a compounding technique. Regarding long-term performance,
By applying the metal layer, a dry atmosphere can be maintained for a long period of time, and the goal is almost achieved. However, if a cable without a metal layer or a cable with a metal layer is subjected to an unexpected load due to a sudden accident, the insulator may be exposed to high temperatures due to the high temperature of the insulator. Is mixed or generated, foreign matter in the insulator,
Water tree degradation caused by condensation of moisture in the high electric field at voids or irregularities at the interface between the insulator and the inner or outer semiconductive layer (forming conductive dendritic channels and eventually leading to dielectric breakdown) Is known) and the effect of oxidative degradation is a concern.

[0004] Various antioxidants have been added to insulators to improve the long-term performance of polyolefin resin insulated power cables. For example, JP-A-58-
No. 191731 discloses 4,4′-thiobis (3-methyl-6-t
--Butylphenol) and bis [2-methyl-4- (3-n-alkylthiopropionyloxy) -5-t-butylphenyl] sulfide can improve the heat aging resistance of the crosslinked polyethylene composition. It has been disclosed. JP-A-4-184814 discloses that a phenolic antioxidant is used in combination with dilauryl-thiodipropionate or distearylthiodipropionate to prevent burning of a crosslinked product of a polyolefin-based resin composition and to provide a highly crosslinked product. Degrees are shown. Further, Japanese Patent No. 2592263 discloses an insulator for electric wires and cables which suppresses bloom of an antioxidant by using a phenolic antioxidant and an amine antioxidant in combination, and has a high degree of crosslinking and excellent heat aging characteristics. It is shown. In these prior arts, it is thought that there is a certain effect in improving the degree of cross-linking of the cross-linked polyolefin insulator, and in improving the processability and heat aging resistance. Was not disclosed.

Further, Japanese Patent Laid-Open No. 10-162650,
JP-A-10-162657 discloses that a triazole-based ultraviolet absorber is added to a crosslinked polyolefin to prevent the generation of water due to decomposition of dicumyl peroxide (hereinafter referred to as DCP) or to be generated with electroluminescence. There is disclosed a technique of absorbing ultraviolet rays to prevent insulation deterioration. Further, Japanese Patent Application Laid-Open No. 8-31241 discloses a power cable having a crosslinked polyolefin insulator layer to which an organic peroxide and a thiocarboxylic acid ester-based antioxidant are added and the amount of the antioxidant extracted by a solvent is reduced. It is shown that tan δ at high temperature and high electric field does not increase, that is, the initial electrical properties are excellent, and the oxidation resistance is excellent. However, these prior arts also aim to improve the initial electrical characteristics of power cables.However, after examining the durability of insulators when exposed to a high electric field for a long period from the viewpoint of electrical performance, sufficient consideration has been given. It is hard to say that it provides a means of improvement. JP-A-9-194645 discloses that a liquid additive or another additive is dissolved in a liquid additive and added as a method for improving the electrical performance of a crosslinked olefin resin insulator. Have been. And by using an amide compound and an amine compound,
Increased solubility of 4,4'-thiobis (3-methyl-6-t-butylphenol), bis [2-methyl-4 {3-n-alkyl (C12 or C14) thiopropionyloxy} -5-t [Butylphenyl] sulfide, ditridecylthiodipropionate and the like can be incorporated in small amounts. However, the present invention focuses on the use of a liquid additive as a means for preventing the formation of foreign substances, and although effective for improving the initial electrical properties, the amide compound used in the present invention. In part, because the amino compound is not strongly basic to improve the aging performance of polyolefins, the present invention over a long period of time, to study the durability of the insulator when exposed to a high electric field, a sufficient It is hard to say that it provides a means of improvement.

[0006]

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide an insulated cable having improved long-term service life of a power cable insulator under a high electric field and having excellent long-term stability. As an issue.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies on the effects on the electrical properties of an insulator over a long period of time, for example, by using various additives in combination. The inventors have found that the power application characteristics are significantly improved, and have completed the present invention. That is, a feature of the present invention is a cross-linking insulating composition obtained by adding an organic peroxide and a hindered phenol compound to a polyolefin resin, and further comprising (A) a compound having a -SR group. -R
Is an alkyl group having 8 or more carbon atoms and (B) a hindered amine compound represented by the following general formula 1.

[Chemical formula 1] Incidentally, specifically (B), (B-1): molecular weight 1500
0.05 to 2.0 parts by weight of the above hindered amine, or (B-2): a compound having a hindered amine group in the molecule, wherein the hindered amine group is a tertiary amine 0.01 to 0.5 part by weight Department, can be used.

[0008] More specifically, (B-1)
[{6- (1,1,3,3-tetramethyl) amino-1,3,5-triazine
2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {2,2,6,6-tetramethyl-4-piperidyl) imino}], or N, N'-bis (3-aminopropyl) ethylenediamine 2,4-bis [N-butyl-N- (1,2,2,6,
6-pentamethyl-4-piperidyl) amino] -6-methyl-1,3,5-
Triazine condensates and the like can be used.

In addition, (B-2) includes bis (1,2,2,6,6-
(Pentamethyl-4-piperidinyl) sebacate, or
Bis (1,2,2,6,6-pentamethyl-4-piperidyl) 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate or dimethyl succinate 1- (2-hydroxyethyl) -4-4-2,2,6,6-tetramethylpiperidine polycondensate and the like can be used.

Next, the present invention provides an electric wire or cable obtained by coating a conductor with the above-mentioned plastic insulating composition.
Further, the present invention provides a cable connecting portion, wherein the plastic insulating composition is formed as an insulator of the cable connecting portion.

According to the present invention, the above-mentioned problems have been solved, and the service life of a power cable insulator under a high electric field can be improved by using a hindered phenol-based antioxidant, (A) and This is because it has been found that the combined use of (B) can drastically suppress the deterioration of the insulator under a high electric field. Although the reason is not clear, the effect of the hindered phenolic antioxidant as a radical trapping agent and the effect of (A) as a peroxide decomposing agent also have a function of suppressing the decomposition of DCP at high temperatures ( According to B), it is considered that it was extended synergistically. In general, when an amine-based antioxidant and a sulfur-based antioxidant are used at the same time, an antagonistic effect is observed, causing bleeding, discoloration, or deterioration of the function of preventing deterioration. A major feature is that by selecting a weakly basic hindered amine as above, even when these are used in combination, this antagonistic effect can be prevented from being recognized.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, dimyristyl-3,3'-thiodipropionate is used as the compound having (A) -SR group in which -R is an alkyl group having 8 or more carbon atoms. , Dilauryl-3,3'-thiodipropionate, pentaerythrityltetrakis (3-laurylthiopropionate), distearyl-3,3'-thiodipropionate,
Thiocarboxylic acid esters such as ditridecyl-3,3'-thiodipropionate, bis [2-methyl-4- (3-n-alkylthiopropionyloxy) -5-t-butylphenyl] sulfide, 2,4-bis [ (Octylthio) methyl] -o-cresol,
Or 2,4-bis (n-octylthio) -6- (4-hydroxy
3,5-di-t-butylanilino) -1,3,5-triazine and the like can be used. These compounds are considered to play a role in suppressing the progress of the degradation by decomposing the hydroperoxide generated during the oxidative degradation of the insulator into a stable compound.

The above (A) is used in an amount of 0.05 to 100 parts by weight of the polyolefin resin constituting the crosslinkable insulator.
It is preferred to add 1.0 part by weight. 0.0%
If the amount is less than 5 parts by weight, the effect of preventing the deterioration of the insulator becomes insufficient. If the amount exceeds 1.0 part by weight, the surface of the insulator bleeds and the tracking resistance is reduced. From the balance between the deterioration prevention effect and the bleeding property, the amount of (A)
The range of 0.1 to 0.5 part by weight is more preferable.

The hindered phenolic antioxidants used in the present invention include 4,4'-thiobis (3-methyl-6-t-t-
Butylphenol), 3,9-bis [2- {3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-
Dimethylethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane, 2,6-di-t-butyl-4-methylphenol and the like. These compounds play a role of capturing peroxy radicals generated at the time of oxidative deterioration of the insulator and stopping the chain reaction. Also, there is an effect of preventing scorch during extrusion.

The hindered phenolic antioxidant is a polyolefin resin 10 constituting a crosslinkable insulator.
It is preferable to add 0.05 to 1.0 part by weight to 0 part by weight. If the amount is less than 0.05 part by weight, the effect of preventing the deterioration of the insulator becomes insufficient. If the amount exceeds 1.0 part by weight, the crosslinking of the insulator is inhibited, and the surface of the insulator bleeds to prevent tracking. Will reduce the performance. The amount of the hindered antioxidant is more preferably in the range of 0.1 to 0.5 part by weight in view of the balance between the deterioration preventing effect, the crosslinking efficiency and the bleeding property.

The hindered amine compound (B) used in the present invention is (B-1) a hindered amine polymer having a molecular weight of 1500 or more, for example, poly [{6- (1,1,3,3)
-Tetramethyl) amino-1,3,5-triazine 2,4-diyl}
{(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {2,2,6,6-tetramethyl-4-piperidyl) imino}], N, N'-bis (3- Aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino] -6-methyl-1,3,5-triazine condensate,
Etc. can be used. These high molecular weight hindered amine compounds are less likely to cause bleeding and have excellent heat resistance.
When used in combination with (A) and a hindered phenol compound, an excellent effect of preventing long-term deterioration of electrical properties is exhibited. Generally, amine compounds or amide compounds having a strong basicity exhibit an antagonistic effect when used in combination with a sulfur compound such as (A), and tend to cause bleeding, discoloration, and deterioration of performance for preventing deterioration. However, it is a unique effect that such a disadvantage does not appear in the high molecular weight hindered amine (B-1). Among the above compounds, from the viewpoint of preventing deterioration of electrical characteristics, poly
[{6- (1,1,3,3-tetramethyl) amino-1,3,5-triazine
2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {2,2,6,6-tetramethyl-4-piperidyl) imino}], and N, N'-bis (3-aminopropyl) ethylenediamine ・ 2,4-bis [N-butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino] -6-methyl 1,3 The 5,5-triazine condensate is particularly preferred.

The above (B-1) is used in an amount of 0.05 to 100 parts by weight of the polyolefin resin constituting the crosslinkable insulator.
It is preferable to add the compound in an amount of up to 2.0 parts by weight. The blending amount is 0.
If the amount is less than 05 parts by weight, the effect of preventing the deterioration of the insulator becomes insufficient, and if it exceeds 2.0 parts by weight, the effect of preventing the deterioration hardly increases any further, causing a cost increase. Would. From the viewpoint of the balance between the deterioration preventing effect and the cost, the amount of (B-1) is more preferably in the range of 0.1 to 0.5 part by weight.

In the present invention, the specific hindered amine (B) is (B-2) a compound having a hindered amine group in the molecule, wherein the hindered amine group is a tertiary amine. Screw (1,2,2,6,6
-Pentamethyl-4-piperidinyl) sebacate, 2- (3,5-di
-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl) or dimethyl succinate 1- (2-hydroxyethyl) -4-2,2,
6,6-tetramethylpiperidine polycondensate and the like can be used. In the present invention, (B-2) is the same as (B-1),
When used in combination with (A) and a hindered phenolic antioxidant, an excellent effect of preventing long-term deterioration of electrical properties is exhibited. In general, a strongly basic amine antioxidant exhibits an antagonistic effect when used in combination with a sulfur compound such as (A), and tends to cause bleeding, discoloration, and deterioration in performance of deterioration prevention. However, the hindered amine of (B-2) does not show such disadvantages, which is a unique effect.

The above (B-2) is used in an amount of 0.01 to 100 parts by weight of the polyolefin resin constituting the crosslinkable insulator.
It is preferable to add 0.5 parts by weight. The blending amount is 0.
When the amount is less than 0.1 part by weight, the effect of preventing the deterioration of the insulator becomes insufficient, and when the amount exceeds 0.5 part by weight, the effect of preventing the deterioration hardly increases any further. turn into.

The polyolefin resin used in the present invention is not particularly limited, but includes low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, linear very low density polyethylene, and ethylene-propylene copolymer. And copolymers of ethylene, butene, ethylene ethyl acrylate, and ethylene vinyl acrylate. These can be used alone or in combination of two or more.

The organic peroxide used in the present invention is not particularly limited, but includes DCP, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5 -Di (t-
Butyl peroxy) hexane-3, α, α'-bis (t-butylperoxy-m-isopropyl) benzene, etc., which are usually used for peroxide crosslinking of polyolefin resins, may be mentioned. The compounding amount of these organic peroxides is based on 100 parts by weight of the polyolefin resin constituting the crosslinkable insulator.
It is preferably 0.5 to 3.0 parts by weight. If the amount is less than 0.5 part by weight, the required degree of crosslinking cannot be obtained, and if it exceeds 3.0 parts by weight, scorch is extremely likely to occur during extrusion.

The plastic insulating composition of the present invention can be produced by kneading with a commonly used extruder-type mixer or Banbury mixer.

The plastic insulating composition of the present invention is preferably applied to a thick high-voltage power cable having a coating thickness of 2.0 mm or more.

The above-mentioned electric wire (cable) is extruded and coated on a conductor by using an extruder as usual, and VCV,
It can be produced by cross-linking using a vulcanizing equipment such as CCV.

[0025] The plastic insulating composition of the present invention can be used as a tape wound joint,
It can be used for extrusion mold joints, block mold joints, etc.

[0026]

The present invention will be specifically described below with reference to the compositions of Examples and Comparative Examples. Evaluation of the insulating compositions (for electric wires / cables and connecting portions) of these examples was performed by the following long-term power application test. (Long-term power application test) A block-shaped sample having a thickness of about 5 mm was prepared from the composition of the example and the composition of the comparative example.
As shown in, the needle electrode 1 is inserted into the block 2,
A voltage was applied between the needle electrode 1 and the plate electrode 3 below the block-shaped sample, and the electric tree from the needle tip was observed.
A needle electrode having a tip with a radius of curvature of 10 μm was used, and the distance h between the needle tip and the flat plate electrode was measured for each sample. The applied voltage is 20 kv and 14 kv
And the power application time until the generation of the electrical tree from the tip of the needle was defined as the power application life. The electric field E applied to the tip of the needle is calculated by substituting V: applied voltage h: interval between the tip of the needle electrode and the flat plate electrode, and r: radius of curvature of the tip of the needle electrode into the following Mason's equation. .

[Formula 1]

The composition of the composition (Examples 1 to 13) using the compound of (B-1) as (B) and the composition of the composition of the comparative example (Comparative Examples 1 to 6) are shown in Tables 1 and 2. Shown above. The compositions of these formulations were subjected to the above-described long-term power application test, and the results are shown in Tables 1 and 2 below.

[0028]

[Table 1]

Note 1) LDPE: low density polyethylene, (density
0.917, melting point 109 ° C, MFR1.1) * 2) DCP: Dicumyl peroxide * 3) Antioxidant c1: 4,4'-thiobis (3-methyl-6-t-butylphenol) * 4) Antioxidant a11: Dimyristyl 3,3'-thiodipropionate * 5) Antioxidant a2: 2,4-bis [(octylthio) methyl] -o-cresol * 6) Antioxidant a3: 2,4-bis (n -Octylthio) -6- (4
-Hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine Note 7) Antioxidant a12: Dilauryl 3,3'-thiodipropionate Note 8) Antioxidant a13: Pentaerythrityl tetrakis
(3-Laurylthiopropionate) Note 9) Antioxidant a14: Distearyl-3,3'-thiodipropionate Note 10) Antioxidant a15: Ditridecyl-3,3'-thiodipropionate Note 11 ) Light stabilizer b11: poly [{6- (1,1,3,3-tetramethyl)
Amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {2,2,6,
6-Tetramethyl-4-piperidyl) imino}] Note 12) Light stabilizer b12: N, N'-bis (3-aminopropyl) ethylenediamine · 2,4-bis [N-butyl-N- (1,2 , 2,6,6-Pentamethyl-4-piperidyl) amino] -6-methyl-1,3,5-triazine condensate

[0030]

[Table 2]

Note 1) LDPE: low density polyethylene, (density
0.917, melting point 109 ° C, MFR1.1) * 2) DCP: Dicumyl peroxide * 3) Antioxidant c1: 4,4'-thiobis (3-methyl-6-t-butylphenol) * 4) Antioxidant a11: Dimyristyl 3,3'-thiodipropionate * 5) Antioxidant a2: 2,4-bis [(octylthio) methyl] -o-cresol * 6) Antioxidant a3: 2,4-bis (n -Octylthio) -6- (4
-Hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine Note 7) Antioxidant a12: Dilauryl 3,3'-thiodipropionate Note 8) Antioxidant a13: Pentaerythrityl tetrakis
(3-Laurylthiopropionate) Note 9) Antioxidant a14: Distearyl-3,3'-thiodipropionate Note 10) Antioxidant a15: Ditridecyl-3,3'-thiodipropionate Note 11 ) Light stabilizer b11: poly [{6- (1,1,3,3-tetramethyl)
Amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {2,2,6,
6-Tetramethyl-4-piperidyl) imino}] Note 12) Light stabilizer b12: N, N'-bis (3-aminopropyl) ethylenediamine · 2,4-bis [N-butyl-N- (1,2 , 2,6,6-Pentamethyl-4-piperidyl) amino] -6-methyl-1,3,5-triazine condensate

The composition of the composition (Examples 14 to 25) using the compound of (B-2) as (B) is shown in the upper part of Table 3. The compositions of these formulations were each subjected to the above-mentioned long-term power application test, and the results are shown in the lower part of Table 3.
The results of the long-term power application test shown in Tables 1 to 3 are plotted on a log-log graph as shown in FIG. It is recognized that the application life of each of the examples is significantly longer than that of the comparative example.

[0033]

[Table 3]

Note 1) LDPE: low density polyethylene, (density
0.917, melting point 109 ° C, MFR1.1) * 2) DCP: dicumyl peroxide * 3) Antioxidant c1: 4,4'-thiobis (3-methyl-6-t-butylphenol) * 13) Antioxidant c2: 3,9-bis [2- {3- (3-tbutyl-4-
(Hydroxy-5-methylphenyl) propionyloxy} -1,
1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5.5]
Undecane * 4) Antioxidant a11: Dimyristyl 3,3'-thiodipropionate * 5) Antioxidant a2: 2,4-bis [(octylthio) methyl] -o-cresol * 6) Antioxidant a3: 2,4-bis (n-octylthio) -6- (4
-Hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine Note 7) Antioxidant a12: Dilauryl 3,3'-thiodipropionate Note 14) Light stabilizer b21: Bis (1, 2,2,6,6-pentamethyl-
4-Piperidinyl) sebacate Note 15) Light stabilizer b22: Bis (1,2,2,6,6,2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate -Pentamethyl-4-piperidyl) Note 16) Light stabilizer b23: Polycondensate of dimethyl succinate / 1- (2-hydroxyethyl) -4-2,2,6,6-tetramethylpiperidine

[0035]

As described above, since the plastic insulating composition of the present invention has a stable long-term power application performance, it is used as a covering material for electric wires and cables having a high electric field and a power cable connecting portion. Thereby, the reliability of the power cable can be improved.

[Brief description of the drawings]

FIG. 1 shows a method for long term application of the composition of the present invention.

FIG. 2 shows the long-term charge life of various compositions.

[Explanation of symbols]

 1 Needle electrode 2 Block sample 3 Electrode plate

Continued on the front page (72) Inventor Yoshiyuki Inoue 1-3-1 Shimaya, Konohana-ku, Osaka-shi, Osaka F-term in Sumitomo Electric Industries, Ltd. Osaka Works 4J002 BB031 BB051 BB051 BB071 BB151 EJ027 EK036 EL127 EU088 EU188 EV069 EV077 EV079 EV349 GQ01 5G305 AA02 AA04 AA14 AB01 AB24 BA12 BA22 BA24 CA01 CA54 CB11 CB16 CB25 CD05 CD09

Claims (5)

[Claims] 1. A cross-linking insulating composition obtained by adding an organic peroxide and a hindered phenolic compound to a polyolefin-based resin, wherein (A) a compound having an —SR group, A plastic insulating composition comprising a compound having an alkyl group having 8 or more carbon atoms and (B) a hindered amine compound represented by the general formula 1. [Chemical formula 1] 2. The plastic insulating composition according to claim 1, wherein (B) is (B-1) a hindered amine having a molecular weight of 1500 or more, and the amount added is 100 parts by weight of the polyolefin resin. And 0.05 to 2.0 parts by weight. 3. The plastic insulating composition according to claim 1, wherein (B) is (B-2) a compound having a hindered amine group in a molecule, wherein the hindered amine group is a tertiary amine. A plastic insulating composition, wherein the amount of the plastic insulating composition is 0.01 to 0.5 part by weight based on 100 parts by weight of the polyolefin resin. 4. An electric wire or cable obtained by coating a conductor with the plastic insulating composition according to claim 1. 5. A cable connecting part, wherein the plastic insulating composition according to claim 1 is formed as an insulator of the cable connecting part.