JPS5919143B2 - Polymer composition for electrical insulation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrically insulating polymer composition with excellent voltage resistance properties.

Electrically insulating polymers such as polyolefins have excellent electrical properties, mechanical properties, and chemical stability. Among them, polyethylene has low dielectric loss and can be crosslinked to improve its heat resistance, making it suitable for extrusion coated insulated cables. It is widely used as an electrical insulating material for electrical equipment such as. However, the inherent voltage resistance characteristics of polyolefins are usually impaired due to minute amounts of impurities contained in commercially available polymers or impurities mixed in during molding, voids, and voids (boards).

Furthermore, in polyolefins, especially polyethylene or 5-crosslinked polyethylene, a tree-like deterioration erosion path called the tree phenomenon is formed inside the polymer in the precursor stage leading to dielectric breakdown, and the electrical properties of the polymer rapidly deteriorate. Additionally, there is the disadvantage that dielectric breakdown occurs via this erosion path.

10 In order to improve this drawback, attempts have been made to add substances called voltage stabilizers to polymers.

As the voltage stabilizer, organic substances such as certain aromatic hydrocarbons, aromatic amino compounds, and certain surfactants are used.

However, it cannot be said that the effect of improving voltage strength of conventionally known voltage stabilizer polymers is necessarily sufficient, and in particular, there is a major drawback in that the voltage strength of crosslinked polyethylene cannot be further improved. The present invention has been made in view of the above, and is based on the fact that N,N-disubstituted anilines are used in electrically insulating polymers, especially crosslinked polyethylene.
It was developed based on the inventors' new findings that it not only has a remarkable effect as a voltage stabilizer, but also has no adverse effect on the appearance or mechanical properties of the polymer. The present invention proposes an electrically insulating polymer composition comprising an electrically insulating polymer and an N,N-disubstituted aniline.

30 The voltage stabilizer used in the present invention has the general formula R_,
/,,C" (here, R_,, R_2 is an alkyl group with or without a substituent, and the total number of carbon atoms including the number of carbon atoms in the substituents is 2 to 15, R3 is hydrogen, alkyl An N,N-disubstituted aniline compound represented by a group, an alkoxy group, a human oxy group, and the total number of carbon atoms is 15 or less is used.

Examples of such N,N-disubstituted anilines include the following 1-
Examples include:

These N,N-disubstituted anilines may be used alone or in combination as a voltage stabilizer in the present invention.

The amount of the N,N-disubstituted aniline compound is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 3 parts by weight, based on 100 parts by weight of the polyolefin.

In the present invention, cables,
Polio-3 reflexes, which are commonly used for electrical insulation of electrical equipment such as transformers, are used.

In particular, the following general formula (in the above, R represents H, or an alkyl group, alkenyl group, or aryl group having 7 or less carbon atoms).

) Olefin polymer copolymers are preferred. Examples of such polyolefins include polyethylene, polypropylene, polybutene-1, ethylene-vinyl acetate copolymer, polystyrene, and the like.

Among these, polyethylene is particularly preferred. Furthermore, the polyolefins used in the present invention may be a mixture of the above representative examples, or the polyolefins may be combined with a small amount of other polymers, such as ethylene-propylene copolymer, ethylene-propylene-diene terpolymer, polymethyl acrylate,
polymethyl methacrylate, 1,2-polybutadiene,
1,4-polybutadiene and the like may be contained in an amount of 20% by weight or less. The composition of the present invention can be easily produced by mixing a polyolefin and an N,N-disubstituted aniline using a conventional mixing device and method.

Furthermore, the composition of the present invention contains an organic peroxide or an organic peroxide monosulfur crosslinking agent and, if necessary, a vulcanization accelerator such as a thiuram type, a thiazole type, a dithioic acid type, an imidazoline type, a thiourea type, or a guanidine type. Even if it is added and crosslinked, the effect of improving the withstand voltage strength is not impaired in any way. Furthermore, antioxidants, ultraviolet absorbers, carbon black, fillers, etc. can also be added to the composition of the present invention by known methods.

However, when the composition of the present invention is coexisting with one or a mixture of two or more of the following polyhydric alcohols, dispersants, or surfactants, the withstand voltage strength is further improved and the withstand voltage strength is also increased. Variations become smaller and stabilized.

The preferred amount of these substances is 0.05 to 10 parts by weight, particularly 0.2 to 5 parts by weight, per 100 parts by weight of polyolefin. As the polyhydric alcohol, one having two or more hydroxyl groups in the molecule is used. Examples of such polyhydric alcohols include: 1) Aliphatic polyhydroxy compounds, such as ethylene glycol, propylene glycol, polyethylene glycol, glycerin, etc. 2) Aromatic polyhydroxy compounds, such as bis-resorcin-ethylene ether, bis-2,3- Examples include hydroxyphenylurea, 3,5-resorcinic acid ethanolamide, 2,4-resorcinic acid ethanolamide, and the like.

As the above-mentioned dispersant, those commonly used in rubbers and plastics can be used.

Examples include those having structures such as higher fatty acid metal salts, higher fatty acid hydrophilic esters, and polyethylene glycol alkyl ethers.

A commercially available product is Plasticol T from West Germany's Rhein Hemi.
Examples include Acting B1 from AHL Yoshitomi Pharmaceutical Co., Yodoplast from Yodogawa Kasei Co., Ltd., and Dispanol M-4 from NOF Corporation.

As the above-mentioned surfactant, the following types of surfactants are used.

1) Amine type: Examples include octinoleamine, tallow alkylamine, dodecyldimethylamine, tallow alkylpropylene diamine, and the like.

2) Nonionic: For example, oxyethylene dodecylamine, polyoxyethylene tallow alkylpropylene diamine, polyoxyethylene oleyl ether, polyoxyethylene alkylaryl ether, polyoxyethylene glycol monostearate, sorbitan monostearate, polyoxy Examples include ethylene alkylamide and polyoxyethylene dodecyl mercaptoether.

3) Cationic type: Examples include dodecyltrimethylammonium chloride, polyoxyethylenedodecylmonomethylammonium chloride, polyoxyethylenealkylamine, and polyamineamide.

4) Anionic type: Examples include fatty sodium, sodium alkylbenzene sulfonate, and sodium higher alcohol sulfate.

5) Ampholytic surfactants: Examples include dimethylxyalkylbetaine and dimethyltallow alkylbetaine.

Examples 1 to 8, Comparative Example 1 Polyethylene (Yukalon ZF36 manufactured by Mitsubishi Yuka Co., Ltd.) and
Additives shown in the table and roll mill at 110-115℃, 1
The mixture was kneaded for 0 minutes to obtain compositions of Examples and Comparative Examples.

Each composition was heated at 120° C. for 20 minutes, or without such heating, and subjected to the bird development test described below to measure the withstand voltage strength.

Table 1 shows the arithmetic mean value and maximum and minimum values of the 10 test data. Bird development test method...2
5×25×311! A piece of the composition was heated from room temperature to 12
A piece of the above composition was heated at 0°C for 5 minutes and then subjected to temperature treatment under the same conditions to obtain a needle end angle of 30'. A polished cotton needle with a needle end radius of curvature of 3 μm or less was inserted into the composition at a speed of 311/min.

The needle was inserted to a depth such that the distance between its tip and the opposing surface of the composition piece was 10 mm. After cooling, the composition piece into which the needle was inserted was left at room temperature for 7 days, and then the voltage generated by the sample was measured using the direct-to-ground method (distance between electrodes: 1011). In that case, the sample has an initial voltage of 8
After that, apply AC voltage using a step-up method that increases the voltage by 3KV every 10 minutes.Before increasing the voltage, visually or microscopically observe the sample to see if it has occurred. The dielectric strength was determined as the withstand voltage strength. Examples 9-17
, Comparative Example 2 Polyethylene (Yukalon ZF36 manufactured by Mitsubishi Yuka Co., Ltd.) 100
part by weight, 2 parts by weight of dicumyl peroxide, and the additives shown in Table 2 at 115 to 120°C for 15 minutes in a roll mill.
The mixture was kneaded for minutes to obtain compositions for each example and comparative example.

Next, each composition was heated to 165°C and 150KP/C! Press crosslinking was carried out for 45 minutes under the temperature and pressure conditions of 1 liter to obtain a 3u thick crosslinked sheet.

Next, a 25×25×311 sample piece was cut from each sheet, and the withstand voltage strength of each crosslinked piece was measured using the bird development test method. Table 2 shows the arithmetic mean value and maximum and minimum values of the 10 test data.

Claims (1)

[Claims] 1. Polyolefin and per 100 parts by weight, 0.
01 to 10 parts by weight, general formula ▲ Numerical formula, chemical formula, table, etc. N,N-disubstituted aniline compound having a number of 2 to 15, R_3 is hydrogen, an alkyl group, an alkoxy group, or a hydroxy group, and the total number of carbon atoms is 15 or less). A polymer composition for electrical insulation.