JP2002083516A - Electrical insulating resin composition and electric wire/ cable covered with it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrical insulating resin composition and an electric wire/cable covered with it, ensuring resistance to blooming and color change, scorching resistance, working stability, water tree resistance, thermal deformation resistance, heat aging resistance, and in addition having low deterioration in crosslinking characteristic caused by storage under high temperature, or high storage stability, similar to the electrical insulating composition and the electric wire/cable obtained by the existing technology. SOLUTION: This electrical insulating resin composition contains ethylene base resin (A), a stabilizer (B), and an organic peroxide (C), and the stabilizer (B) is composed of at least one kind of hindered phenol type stabilizer (B1), at least one kind of dialkylthiodipropionate type stabilizer (B2), and at least one kind of hindered amine type stabilizer (B3), and the electric wire/cable is manufactured by covering the electrical insulating resin composition on an insulating material and crosslinking.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrically insulating resin composition comprising an ethylene resin, and an electric wire or cable obtained by coating a conductor with the electrically insulating resin composition and crosslinking the conductor. More specifically, an electrical insulating composition comprising a crosslinkable ethylene-based resin that prevents blooming and discoloration, has excellent scorch resistance and processing stability, and has a high degree of storage stability, and the electrical insulating resin composition The present invention relates to a wire / cable using a material having excellent water tree resistance, heat deformation resistance, and heat aging resistance.

[0002]

2. Description of the Related Art Crosslinked polyethylene electric wires and cables are generally prepared by coating an electrically insulating resin composition comprising an ethylene resin with a stabilizer such as an antioxidant and a crosslinking agent comprising an organic peroxide as an insulator on a conductor. The electric wires and cables are generally widely used as outdoor overhead electric wires. When processing electric wires and cables, scorch resistance (scorch is a phenomenon in which organic peroxide is partially decomposed in an extruder and causes cross-linking, making product processing difficult or product failure ) And processing stability (the molten resin composition is extruded from the die head at the exit of the extruder at a constant pressure, temperature, discharge rate, and torque, and the target molded product is stably formed. Physical properties are important indicators, but these physical properties largely depend on the type and amount of the stabilizer used in the electric insulating resin composition.

[0003] In addition, important properties of the manufactured electric wires and cables include water tree resistance, heat deformation resistance, and heat aging resistance. These properties are also stable, such as antioxidants used in electric insulating resin compositions. It depends greatly on the type and amount of the agent. For example, in the case of an electric insulating composition containing a hindered phenol-type stabilizer and a dialkylthiodipropionate-type stabilizer in combination, the electric insulating composition generally has excellent blooming resistance, scorch resistance, and processing stability. According to tests by the inventors of the present invention, when the electrically insulating composition is exposed to a high temperature of, for example, 80 ° C.,
Even under a temperature condition of about 0 ° C., if storage and transport take a long time, the crosslinking property may be reduced and heat resistance may be reduced, and further improvement in storage stability has been expected.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide blooming, discoloration resistance, scorch resistance, processing stability, and water tree resistance equivalent to those of the electric insulating composition and electric wires and cables obtained by the prior art. , Heat deformation resistance, while keeping the heat aging resistance, without further deterioration of the cross-linking characteristics due to storage at high temperatures described above, that is, an electrical insulating resin composition having excellent storage stability and by coating and cross-linking the same. To provide electric wires and cables.

[0005]

Means for Solving the Problems In view of the above problems, the present inventors have developed an ethylene resin composition comprising an ethylene resin, a hindered phenol type stabilizer, a dialkylthiodipropionate type stabilizer and a crosslinking agent. In order to solve the deterioration of the cross-linking property due to long-term storage at high temperature, an experiment was conducted in which various compounds were further added to the above resin composition, and this compound was applied by the present applicant. Thiobisphenol and 3- (3 ', 5'-di-t-butyl-) as hindered phenol type stabilizers disclosed in Japanese Patent Application Laid-Open No. 2000-86831.
(4′-Hydroxyphenyl) propionate is compounded with two kinds of compounds containing in the molecule, and further applied to an electric insulating composition containing distearyl thiodipropionate, the discoloration resistance of the electric insulating composition is improved. The present inventors have found that storage stability is further improved while maintaining properties such as blooming resistance, and the present invention has been completed. That is,
The first invention of the present invention provides an electric insulating resin composition containing an ethylene-based resin (A), a stabilizer (B) and an organic peroxide (C), wherein the stabilizer (B) comprises at least one kind of Hindered phenol type stabilizer (B1), at least 1
Dialkylthiodipropionate-type stabilizers (B
2) and at least one kind of a hindered amine type stabilizer (B3).

According to a second aspect of the present invention, the amount of the stabilizer (B) is based on 100 parts by weight of the ethylene resin (A).
Hindered phenol type stabilizer (B1) 0.01-1.
0 parts by weight, 0.005 to 0.6 parts by weight of a dialkylthiodipropionate type stabilizer (B2), and 0.001 to 0.5 parts by weight of a hindered amine type stabilizer (B3). 1 is an electrical insulating resin composition of the invention of 1). In the third invention of the present invention, the compounding amount of the organic peroxide (C) is based on 100 parts by weight of the ethylene resin (A).
The electrically insulating resin composition according to any one of the first to second inventions, wherein the amount is 0.5 to 3 parts by weight.

In a fourth aspect of the present invention, the hindered phenol-type stabilizer (B1) comprises a hindered phenol-type stabilizer having a thiobisphenol structure and 3- (3 ′, 5′-).
A hindered phenol-type stabilizer containing di-t-butyl-4'-hydroxyphenyl) propionate in the molecule, and the dialkylthiodipropionate-type stabilizer (B2) is distearylthiodipropionate. The electrical insulating resin composition according to any one of the first to third inventions, characterized in that:

[0008] A fifth invention of the present invention is an electric wire or cable obtained by coating the electric insulating resin composition of any one of the first to fourth inventions as an insulator on a conductor and crosslinking the conductor.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

1) Ethylene-based resin (A) In the present invention, ethylene-based resin refers to a high-pressure low-density method.
Ethylene homopolymer, high density ethylene copolymer, medium density
Ethylene copolymer, linear low-density ethylene copolymer, straight
Chain low-density ethylene copolymer, etc.
You. Each of these ethylene resins is a known polymerization method.
Can be manufactured using the high pressure method.
In the case of organic peroxides, azo compounds, oxygen, etc.
For cal generation catalysts and other polymerization methods,
Catalyst, Ziegler catalyst, standard catalyst and
A metallocene catalyst can be exemplified. Copolymerized with ethylene
Α-olefins include propylene, butene-1,
Hexene-1,4-methylpentene-1, octene-
1, decene-1 and dodecene-1 are exemplified. ethylene
The system resin may be used alone or in combination of two or more (for example,
High-pressure method containing two or more low-density ethylene homopolymers)
May be used. In the present invention, the density is 0.91
0.94g / cm³, Preferably 0.915 to 0.93
g / cm³And the melt mass flow rate is 0.01 to 1
High pressure of 0 g / 10 min, preferably 0.5 to 5 g / 10 min
Low density ethylene homopolymer and linear low density ethylene
A copolymer is preferably used. Density 0.91g / c
m ³If less than 0.94 g, the wear resistance is poor.
/ cm³Exceeding the range is not preferred because the flexibility is poor. Ma
In addition, the melt mass flow rate is 0.01 g / 10 minutes or less
Is inferior in processability, while exceeding 10 g / 10 min.
Low mechanical strength, processing stability and heat deformation resistance
Is not preferred.

2) Stabilizer (B) 2-1) Hindered phenol type stabilizer (B1) Hindered phenol type stabilizer (B) used in the present invention
1) may be any antioxidant having a hindered phenol structure, and specifically, 4,4′-thiobis- (3-methyl-6-t-butylphenol) (Seanox manufactured by Shiraishi Calcium Co., Ltd.) BCS), 4,4'-
Thiobis- (6-t-butyl-o-cresol) (Ethanox 736 manufactured by Ethyl Corporation), tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane (Irganox 1010 manufactured by Ciba Specialty Chemicals), N, N'-bis [3- (3,5-di-t-
[Butyl-4-hydroxyphenyl) propionyl] hydrazine (Irganox 1024 manufactured by Ciba Specialty Chemicals), 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid (Cytech) Cyanox 179
0), 1,3,5-trimethyl-2,4-6-tris (3,5-di-t-butyl-4-hydroxybenzyl)
Benzene (Ethanox 330 manufactured by Albert Corporation), triethylene glycol-bis [3- (3
-T-butyl-5-methyl-4-hydroxyphenyl)
Propionate] (Irganox 245 manufactured by Ciba Specialty Chemicals), 1,6-hexanediol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (Irganox manufactured by Ciba Specialty Chemicals) 259), octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate (Irganox 1076 manufactured by Ciba Specialty Chemicals), N, N'-hexamethylenebis (3,5-di- t-butyl-4-hydroxy-hydrocinnamamide (Irganox 1098 manufactured by Ciba Specialty Chemicals), 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-) 4-Hydroxybenzyl) benzene (Ciba Specialty Chemicals) Knox 1330), tris - (3,5-di -t- butyl-4-hydroxybenzyl) - isocyanurate (Ciba Specialty Chemicals Irganox 3114), isooctyl -3
-(3,5-di-t-butyl-4-hydroxyphenyl) propionate (Irganox 1135 manufactured by Ciba Specialty Chemicals), 1,1,3-tris (2-methyl-4-hydroxy-5-t-butyl) Phenyl) butane (Adeka Stub AO-3 manufactured by Asahi Denka Co., Ltd.)
0), 4,4'-butylidenebis- (3-methyl-6-
t-butylphenol (Adeka Stub A manufactured by Asahi Denka Co., Ltd.)
O-40) and the like. Also, 2,2 '
-Thiobis- (4-methyl-6-t-butylphenol) can also be mentioned.

In the present invention, one or more hindered phenol type stabilizers are blended. The amount of the stabilizer is 0.01 to 1.0 part by weight, preferably 0.02 to 0.5 part by weight, based on 100 parts by weight of the ethylene resin. When the hindered phenol type stabilizer is less than the above lower limit, the heat aging resistance and scorch resistance are inferior. Absent.

In the present invention, at least one kind of a hindered phenol type stabilizer having a thiobisphenol structure is used.
0.2 parts by weight and 3- (3 ′, 5′-di-t-butyl-
At least one hindered phenol-type stabilizer containing (4'-hydroxyphenyl) propionate in the molecule;
A hindered phenol type stabilizer consisting of 01 to 0.2 parts by weight can be suitably blended. In this combination,
Problems of low solubility of thiobisphenol type stabilizer in ethylene resin and hindered phenol containing 3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate in the molecule The problem of discoloration of the mold stabilizer is reduced by reducing the amount of each component by using both of them, a synergistic effect is obtained, and an effect effective for blooming and discoloration of the resin composition can be obtained. The electric insulating resin composition of the present invention having good water tree resistance, heat aging resistance and the like can be obtained. Specifically, as a hindered phenol type stabilizer, 4,4′-thiobis- (3-methyl-6-t-butylphenol) and tetrakis [methylene-3- (3 ′, 5′-di-t-butyl) are used. −
4'-Hydroxyphenyl) propionate] methane is a preferred embodiment of the present invention. If the amount of the stabilizer is less than the above lower limit, sufficient heat aging resistance cannot be obtained. On the other hand, if it exceeds the above upper limit, there is no problem in heat aging resistance, but it is not preferable because blooming and discoloration may occur.

[0014] 2-2) dialkyl thiodipropionate stabilizer used in dialkyl thiodipropionate stabilizer (B2) the invention may be those having an alkyl group of _C 10 _{~C 2 0,} Specifically, dilauryl thiodipropionate (DLTP "Yoshitomi" manufactured by Yoshitomi Pharmaceutical Co., Ltd.), distearyl thiodipropionate (DSTP "Yoshitomi" manufactured by Yoshitomi Pharmaceutical Co., Ltd.) and dimyristyl thiodipropionate (Yoshitomi Pharmaceutical Co., Ltd.) DMTP "Yoshitomi") can be suitably used.

In the present invention, one or more dialkylthiodipropionate-type stabilizers are blended. The amount of the stabilizer is 0.00 0.00 parts by weight of the ethylene resin.
It is 5 to 0.6 parts by weight, preferably 0.01 to 0.3 parts by weight. When the amount of the dialkylthiodipropionate-type stabilizer is less than the above lower limit, the heat aging resistance and the scorch resistance are inferior. On the other hand, when the amount exceeds the above upper limit, the discoloration problem and the electrical properties begin to deteriorate. It is not preferable.

2-3) Hindered amine type stabilizer (B)
3) The hindered amine type stabilizer used in the present invention refers to a so-called HALS light stabilizer, and has the following general formula:

Embedded image (Where X is CH ₂ or a carbonyl group, Y is NR ⁴ , R
⁴ is (R ⁵ ) _j W, R ⁵ is a divalent alkylene group having 1 to 10 carbon atoms, j is 0 or 1, W is hydrogen or a bond to another piperidine moiety which forms a polymer, R ³ the ^(R ₆₎ j W, where ^{R 6} is _oxygen, -OC _{n H 2n -,}
Or a linear or branched divalent alkylene group having 1 to 10 carbon atoms, n is an integer of 1 to 12, and R ² is a,
b, c, and d. a: structural formula _{- (C = O) -C m} H 2m + 1 - (C = O)
Z is a divalent group (where m is an integer of 2 to 8, and Z is a heteroatom, a heterocyclic structure, or a bond to another piperidine moiety capable of forming a polymer structure when bonded to W) b: Polymer structure Bond to the R ⁴ group of another piperidine moiety so as to form c: if Y is NR ⁴ , another piperidine moiety may have a heteroatom thereon and / or form a polymer structure triazine ring may bind to d: structural formula _{- (C p H 2p + 1} ) -Si (CH 3) q O
A group having _{(3-q) / 2} (where p is an integer of 0 to 8,
q is an integer of 0 to 2; a silicon atom is an alkyl group having 1 to 18 carbon atoms via a (3-q) oxygen atom, or a silicon atom or Si (CH ₃ ) _r O _{4-r at the} same heterocyclic site; It is bonded to another silicon atom which is a silicon atom at a site (where r is an integer of 0 to 3). ).

Preferred hindered amine type light stabilizers include dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine succinate polycondensate (manufactured by Ciba Specialty Chemicals, Inc.). TINUVIN 622), poly [｛6- (1,1,1)
3,3-tetramethylbutyl) 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 II] (CHiba Specialty Chemicals, CH
IMASSORB 944), N, N'-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- (1,2,2,6,6-pentamethyl-4-
Piperidyl) amino-6-chloro-1,3,5-triazine condensate (manufactured by Ciba Specialty Chemicals, CH
IMASSORB 119), dibutylamine-1,3,
5-triazine-N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine-N- (2,2,6,6-tetramethyl-4
-Piperidyl) butylamine polycondensate (manufactured by Ciba Specialty Chemicals, CHIMASSORB 202)
0) can be mentioned, but the present invention is not limited thereto, provided that it is a hindered amine compound represented by the general formula (1). In the present invention, one or more hindered amine type stabilizers are blended. The amount of the stabilizer is 0.00 0.00 parts by weight of the ethylene resin.
It is 1 to 0.5 part by weight, preferably 0.003 to 0.1 part by weight. When the amount of the hindered amine-type stabilizer is less than the above lower limit, deterioration of the crosslinking property due to storage at a high temperature of the electrical insulating resin composition starts to occur. However, the effect on the properties is saturated, the economy is lost, and the electrical properties and heat aging resistance may start to deteriorate, which is not preferable.

3) Organic peroxide (C) The organic peroxide used in the present invention may be any one usually used as a crosslinking agent in this field. This includes di-t-butyl-peroxide,
1,1-bis-t-butyl-peroxybenzoate,
2,2-bis-t-butyl-peroxybutane, t-butyl-peroxybenzoate, dicumyl peroxide, 2,5-dimethyl-2,5-di-t-butyl-peroxyhexane, t-butyl -Cumyl peroxide,
Examples thereof include 2,5-dimethyl-2,5-di-t-butyl-peroxyhexine-3, and among these, those having a decomposition temperature of 150 to 200 ° C. until a half-life of 1 minute is obtained. Particularly preferred. In the present invention, one or more organic peroxides are blended. The amount of the organic peroxide is 0.5 to 3.0 parts by weight based on 100 parts by weight of the ethylene resin.
Preferably it is 1.0 to 2.5 parts by weight. If the compounding amount of the organic peroxide is less than the above lower limit, the heat deformation resistance is inferior, and on the other hand, the organic peroxide exceeds the above upper limit and the scorch resistance is inferior.

4) Other Components In addition to the above-mentioned ethylene resin, three kinds of stabilizers, and organic peroxides, the electric insulating resin composition of the present invention may be used in a range that does not impair the characteristics of the present invention. Depending on the purpose, other olefin resins, various additives and auxiliary materials can be blended. Other olefin resins, for example, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ionomer, polypropylene,
Styrene-based elastomers and the like can be mentioned. In addition, as various additives and auxiliary materials, other than the above stabilizers, ultraviolet absorbers, antistatic agents, lubricants, processability improvers, flame retardants, fillers, dispersants, copper damage inhibitors, neutralizing agents, As a foaming agent, a chemical foaming agent-containing impurity trapping agent, an air bubble inhibitor, a coloring agent, a pigment, carbon black, and an anti-scorch agent, α-methylstyrene dimer and the like can be mentioned.

5) Electric Insulating Resin Composition The electric insulating resin composition of the present invention comprises a predetermined amount of the above-mentioned components, ie, ethylene resin (A), stabilizer (B1), (B)
2), (B3), the organic peroxide (C), and, if necessary, other components (the above-mentioned various additives, auxiliary materials, etc.) in appropriate amounts. The shape of the electric insulating resin composition of the present invention is, for example, a pellet having an average particle diameter of about 2 to 7 mm, a granular form having an average particle diameter of about 0.2 to 2 mm, and a powder having an average particle diameter of about 0.2 mm or less. However, pellets are preferred because of the ease of handling during processing. Various known methods may be used for granulation into pellets, but in the present invention, the following method (a) or (b) can be preferably used. (A) The above three types of stabilizers, organic peroxides, and if necessary, other resins, additives, auxiliary materials, and the like are blended with the ethylene-based resin, and this blend is mixed with, for example, a Banbury mixer, a continuum. Using a known kneading machine such as an ass mixer, kneader, roll or extruder, after uniformly mixing and kneading at a temperature equal to or higher than the melting temperature of the ethylene-based resin and lower than the decomposition temperature of the organic peroxide, The obtained kneaded material is granulated. (B) blending the above three kinds of stabilizers with an ethylene-based resin, and further, if necessary, other resins, additives, auxiliary materials, etc.,
Using a known kneading machine such as a Banbury mixer, a continuous mixer, a kneader, a roll, or an extruder, the mixture was kneaded at a temperature equal to or higher than the melting temperature of the ethylene resin, and then obtained. Granulate the kneaded material. The granulated material is impregnated with a liquid organic peroxide which is heated to a temperature equal to or higher than the melting point, and if necessary, is aged at a temperature equal to or lower than the melting point in order to obtain a uniform distribution of the organic peroxide. The electrical insulating resin composition of the present invention is capable of preventing blooming and discoloration, and has scorch resistance, processing stability, and high storage stability.

6) Electric Wire / Cable The electric wire / cable of the present invention is obtained by coating the above-mentioned electric insulating resin composition as an insulator on a power cable conductor and cross-linking it. There is no particular limitation, but there is no particular limitation. Usually, the above-mentioned electric insulating resin composition is used, for example, as a single-layer extruder or a three-layer co-extruder (a resin composition for an inner semiconductive layer,
The three layers of the electrical insulating resin composition of the present invention and the resin composition for the outer semiconductive layer are simultaneously coated. ), Extruded at a temperature equal to or higher than the melting temperature of these resin compositions and lower than the decomposition temperature of the organic peroxide, coated on a conductor, and then steamed.
It is manufactured by heating and crosslinking by using a heating medium such as nitrogen or silicone oil, or by heating and crosslinking by a long-ground die. The electric wire / cable obtained by the present invention has excellent properties of water tree resistance, heat deformation resistance, and heat aging resistance.

[0022]

EXAMPLES The present invention will be described below in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. In addition, each physical property in an Example and a comparative example was evaluated by the evaluation method shown below.

Evaluation method Blooming resistance: The electrically insulating resin composition (pellet) of the present invention was allowed to stand in a constant temperature and humidity room at a room temperature of 23 ° C. and a relative humidity of 50% for 30 days. The surface of the pellet was washed with chloroform, and the washed solution was analyzed by liquid chromatography to determine the amount of the individual hindered phenol-type stabilizer (B1) and dialkylthiodipropionate-type stabilizer (B2), and the total amount thereof was determined. Is the amount of blooming. This blooming amount is 1000ppm
The following were accepted.

Scorch resistance: ISO 6502 (Rub
ber) "Measurementof Vulcan
Ization Characteristics w
is Roterless Curemeters "
MDR2000 manufactured by ALPHATETECHNOLOGIES and analysis software Alpha2
Evaluation was performed using 00R. Set the test temperature to 140 ° C and 3
The torque value (lb × in) for 0 minutes was measured, and a sample having a difference between the minimum torque value and the torque value after 30 minutes of 0.5 or less was judged as acceptable.

Processing stability: The electric insulating resin composition (pellet) left at room temperature for 90 days in a single-screw extruder having a screw length (L) and a diameter (D) of 25 (L / D) was heated at a temperature of 1
The mixture was extruded at 25 ° C. for 30 minutes, and after 5 minutes from the start of extrusion, the pressure of the strand die head and the motor torque of the extruder were closely observed.

Heat aging resistance: Evaluated according to JIS C3005, paragraph 19. Tensile strength and residual tensile elongation after 4 days at a heat storage temperature of 160 ° C. were 80% or more.

Heat deformation resistance: Performed according to JIS C3005, paragraph 25, and passed 60% or more.

Water tree resistance: room temperature 23 ° C., relative humidity 50
% In a constant temperature and humidity chamber of 30% for 30 days, the sheet was preformed at 120 ° C. using a press molding machine, and then crosslinked at 180 ° C. for 30 minutes to a thickness of 3 mm. Using the water electrode shown in FIG. 1, an AC voltage of 1 kV / 1000 Hz was applied to the sheet for 500 hours. This sheet was sliced to about 0.1 mm in the thickness direction to prepare 10 sliced pieces, which were immersed in an aqueous methylene blue solution and dyed. The stained slices were observed under a microscope, and a case where generation of water tree was not recognized was regarded as acceptable.

Storage stability: In the present invention, storage stability means that the cross-linking properties of the electrically insulating resin composition are preserved. The electric resin composition (pellet) was prepared at a temperature of 80 ° C. for 24, 48, 72, 96, 120, 168, 192, 2
It was stored for 16 and 240 hours. For each stored pellet, in accordance with ISO 6502 above,
At 180 ° C., the rotor was displaced at an angle of 0.5 ° at a speed of 1.7 Hz, and the change over time in the torque value was measured.
The torque value generally decreases at the initial stage due to heating of the resin composition, and after the minimum torque value, starts to increase as the crosslinking of the resin starts, and after about 7 to 8 minutes, as the decomposition of the organic peroxide is completed, Reaches almost the maximum constant value. In this evaluation, the torque value after 10 minutes was defined as the maximum torque value. The difference between the maximum torque value and the minimum torque value of the sample before the storage test was defined as 100%, and the storage time at which the difference decreased to 80% was calculated and evaluated.

The raw materials and abbreviations used in Examples and Comparative Examples are as follows. Ethylene resin (A) High pressure method low density ethylene homopolymer, melt mass flow rate 3.0 g / 10 min, density 0.923 g / cm ³ (NUC-761 manufactured by Nippon Unicar) Stabilizer (B) Hindered phenol type Stabilizer (B1) Abbreviation (B1 (1)) 4,4′-thiobis- (3-methyl-6-t-butylphenol) (manufactured by Shiraishi Calcium Co., Ltd.)
Seanox BCS) Abbreviation (B1 (2)) tetrakis [methylene-3-
(3 ′, 5′-Di-t-butyl-4′-hydroxyphenyl) propionate] methane (Irganox 1010 manufactured by Ciba Specialty Chemicals) Abbreviation (B1 (3)) octadecyl-3- (3,5-di-)
t-butyl-4-hydroxyphenyl) propionate (Irganox 1076, manufactured by Ciba Specialty Chemicals) Dialkylthiodipropionate type stabilizer (B2) Distearylthiodipropionate (D, manufactured by Yoshitomi Pharmaceutical Co., Ltd.)
STP "Yoshitomi") Hindered amine type stabilizer (B3) Poly [@ 6- (1,1,3,3-tetramethylbutyl)
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}] (CHIMASSORB 944, manufactured by Ciba Specialty Chemicals) Organic peroxide (C) dicumyl peroxide

Example 1 High-pressure low-density ethylene homopolymer (melt mass flow rate: 3.0 g / 10 min, density: 0.923 g / cm ³ )
(NUC-761 manufactured by Nippon Unicar) as a hindered phenol-type stabilizer (B1
(2)) 0.2 parts by weight of tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane (Irganox 1010 manufactured by Ciba Specialty Chemicals), and A stabilizer consisting of 0.1 part by weight of distearylthiodipropionate (DSTP “Yoshitomi” manufactured by Yoshitomi Pharmaceutical Co., Ltd.) is blended as an alkylthiodipropionate-type stabilizer, and poly [｛6- (1 , 1,
3,3-tetramethylbutyl) 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 II] (CHA Specialty Chemicals CH
IMASSORB 944) was blended, melt-kneaded at 180 ° C. for 10 minutes with a Banbury mixer, and then granulated into pellets having a diameter of 2.5 mm and a length of 2.5 mm. Next, dicumyl peroxide liquefied by heating to 60 ° C. was added to the pellets of the ethylene resin 1.
1.6 parts by weight per 00 parts by weight was added, mixed for 30 minutes in a blender and impregnated. The obtained electrical insulating resin composition of the present invention was evaluated for blooming resistance, scorch resistance and processing stability. Further, this electric insulating resin composition was preformed into a sheet at a temperature of 120 ° C. using a press molding machine, and then heated at 180 ° C. for 30 minutes to crosslink.
This cross-linked sheet was punched into a predetermined dumbbell mold, and as a sample, its heat aging resistance, heat deformation resistance and water tree resistance were evaluated by the above-described evaluation methods. Furthermore, the storage stability of the obtained electric insulating resin composition was evaluated by the above-described method before storage and after storage at 80 ° C. for a predetermined time, and the storage stability of cross-linking characteristics was examined. Table 1 summarizes the composition and evaluation results of the electrical insulating resin composition. As is clear from Table 1, the electrical insulating resin composition of the present invention has passed the blooming resistance, the scorch resistance, and the processing stability, and has good heat aging resistance, heat deformation resistance, and water tree resistance. It had excellent properties as an insulating material for electric wires and cables.
In addition, in a storage stability test in which this was stored at 80 ° C., it had a high degree of storage stability that retained excellent crosslinking properties even after 240 hours.

[0032]

[Table 1]

Example 2 In Example 1, the blend of the hindered phenol type stabilizer was 0.1 part by weight of (B1 (1)) 4,4'-thiobis- (3-methyl-6-t-butylphenol), And (B
1 (2)) tetrakis [methylene-3- (3 ′, 5′-
Di-t-butyl-4'-hydroxyphenyl) propionate] methane (manufactured by Ciba Specialty Chemicals)
The test was conducted in the same manner as in Example 1 except that Irganox 1010) was changed to 0.1 part by weight. The composition and evaluation results are summarized in Table 1. As is clear from Table 1, the electrical insulating resin composition of the present invention had excellent characteristics and high storage stability.

Examples 3 and 4 A test was conducted in the same manner as in Example 2 except that the amount of the hindered amine type stabilizer was changed to 0.01 parts by weight and 0.005 parts by weight. The composition and evaluation results are summarized in Table 1. As is clear from Table 1,
These electric insulating resin compositions of the present invention had excellent characteristics and high storage stability.

Example 5 In Example 3, the hindered phenol type stabilizer (B
1 (2)) to (B1 (3)) octadecyl-3- (3,
The test was performed in the same manner as in Example 3, except that 5-di-t-butyl-4-hydroxyphenyl) propionate (Irganox 1076 manufactured by Ciba Specialty Chemicals) was used. The composition and evaluation results are summarized in Table 1. As is clear from Table 1, the electric insulating resin composition of the present invention had excellent characteristics and high storage stability.

Comparative Examples 1 and 2 The procedure of Examples 2 and 5 was repeated except that no hindered amine type stabilizer was used.
Table 2 summarizes the composition and evaluation results. As is clear from Table 2, these electric insulating resin compositions had good properties as an insulating material. No increase was observed, and no maximum torque value was found. Therefore, as compared with the examples, the crosslinking properties were not retained, and the storage stability was significantly inferior.

[0037]

[Table 2]

Comparative Example 3 The procedure of Example 2 was repeated, except that the amount of the hindered amine type stabilizer was increased to 0.8 parts by weight. Table 2 summarizes the composition and evaluation results. As is clear from Table 1, this composition showed good storage stability, but was inferior in heat aging resistance as compared with the examples.

[0039]

According to the present invention, a specific amount of a hindered phenol type stabilizer (B1), a dialkylthiodipropionate type stabilizer (B2) and a hindered amine type stabilizer (B3) are used in combination as stabilizers. And since it is blended with ethylene resin (A) together with a specific amount of organic peroxide (C), there is no problem of blooming or discoloration of hindered phenol type stabilizer and excellent scorch resistance It is an electrical insulating resin composition with excellent processing stability, and has no storage stability problem observed when using a hindered phenol-type stabilizer and a dialkylthiodipropionate-type stabilizer in combination. It has a high degree of storage stability without deterioration of the crosslinking properties. This electric insulating resin composition is coated as an insulator,
The cable has excellent heat aging resistance, heat deformation resistance, and water tree resistance.

[0040]

[Brief description of the drawings]

FIG. 1 is a schematic view of a water electrode used to evaluate water tree resistance.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 5/357 C08K 5/357 5/372 5/372 5/375 5/375 C08L 23/04 C08L 23 / 04 H01B 7/02 H01B 7/02 F (72) Inventor Yumi Oki 2-18-18 Ichiharakamimachi, Tsurumi-ku, Yokohama, Kanagawa Prefecture (72) Inventor Koji Ishihara 7-16-12, Ebara, Shinagawa-ku, Tokyo F-term (reference) 4J002 BB031 BB051 BB151 EJ036 EJ046 EJ066 EP026 EU078 EU088 EU196 EV067 EV076 EW026 FD036 FD037 FD038 5G305 AA02 AB27 AB36 BA12 BA13 CA01 CA08 CA51 CA54 CB11 CB14 RA05 CD12 RA05

Claims (5)

[Claims] 1. An electric insulating resin composition containing an ethylene resin (A), a stabilizer (B) and an organic peroxide (C), wherein the stabilizer (B) is at least one kind of hindered phenol type. An electrically insulating resin composition comprising a stabilizer (B1), at least one dialkylthiodipropionate-type stabilizer (B2), and at least one hindered amine-type stabilizer (B3). 2. The compounding amount of the stabilizer (B) is 0.01 to 1.0 part by weight of the hindered phenol type stabilizer (B1) and 100 parts by weight of the ethylene-based resin (A). Pionate type stabilizer (B2) 0.005
0.6 parts by weight, and a hindered amine type stabilizer (B
3) The electrically insulating resin composition according to claim 1, wherein the amount is 0.001 to 0.5 parts by weight. 3. The composition according to claim 1, wherein the amount of the organic peroxide (C) is 0.5 to 3 parts by weight based on 100 parts by weight of the ethylene resin (A). The electrical insulating resin composition according to any one of the above. 4. Hindered phenol type stabilizer (B1)
Has a hindered phenol type stabilizer having a thiobisphenol structure and 3- (3 ′, 5′-di-tert-butyl-4 ′)
(Hydroxyphenyl) propionate in the molecule and a hindered phenol type stabilizer, wherein the dialkylthiodipropionate type stabilizer (B2) is distearylthiodipropionate. 3. The electrically insulating resin composition according to any one of items 3. 5. An electric wire or cable obtained by coating and cross-linking the electrically insulating resin composition according to claim 1 on a conductor as an insulator.