JPS5952176B2 - 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, so it is used for extrusion coated insulated cables, etc. It is widely used as an electrical insulating material for electrical equipment. However, the inherent voltage resistance characteristics of polyolefins are usually impaired due to minute amounts of impurities contained in commercially available polymers, impurities mixed in during molding, voids, and voids (boards).

Furthermore, in polyolefins, especially polyethylene or cross-linked polyethylene, tri-oxidization occurs in the precursor stage leading to dielectric breakdown.
There is a disadvantage that a deterioration erosion path called a phenomenon is formed inside the polymer, and the electrical properties of the polymer are rapidly deteriorated, and dielectric breakdown is caused via this erosion path. In order to improve this drawback, attempts have been made to add substances called voltage stabilizers to polymers.
As this voltage stabilizer, organic substances such as certain aromatic hydrocarbons, aromatic amino compounds, or certain surfactants are used. However, the effect of improving voltage strength of conventionally known voltage stabilizer polymers is not 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 has not only remarkable effects as a voltage stabilizer for aromatic P-substituted or O-substituted aldehyde electrically insulating polymers, especially crosslinked polyethylene, but also It was developed based on the new findings of the present inventors that it does not have any adverse effect on the appearance or mechanical properties of the polymer, and it is an electrically insulating polymer and an aromatic P-substituted or 0-substituted polymer. The present invention proposes an electrically insulating polymer composition comprising aldehydes.

The aromatic P-substituted or 0-substituted aldehydes used as voltage stabilizers in the present invention are of the following formula I-X
Those indicated by (2) are preferred.

ClBrNH2CH3-N-CH3Proposed Medium CHOCHOCHOCHO I ■ ■ ■ The blending amount of these aromatic P-substituted or O-substituted aldehydes is 0.0 parts by weight per 100 parts by weight of polyolefin.
It is preferably 1 to 10 parts by weight, more preferably 0.
．． 1 to 3 parts by weight.

In the present invention, cables,
Polyolefins commonly used for electrical insulation of electrical equipment such as transformers are used. In particular, it represents the following general formula (in the above, R is H) or an alkyl group, alkenyl group, or aryl group having 7 or less carbon atoms.

Polymers and copolymers of olefins represented by 5) are preferred, and examples of such polyolefins include aliphatic polyolefin resins such as polyethylene, polypropylene, polybutene-1, and ethylene-vinyl acetate copolymers, especially 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-pyrene-diene terpolymer, polyolefin, etc. Methyl acrylate, polymethyl methacrylate, 1,
2-polybutadiene, 1,4-polybutadiene, etc.
It may be contained in a range of 0% by weight or less. The composition of the present invention comprises a polyolefin and an aromatic P monosubstituted or O-
It can be easily produced by mixing substituted aldehydes with a conventional mixing device and method. Furthermore, the composition of the present invention can be vulcanized with an organic peroxide or an organic peroxide-sulfur crosslinking agent and, if necessary, a thiurame-based, thiazole-based, dithioic acid-based, imidazoline-based, thiourea-based, or guanidine-based crosslinking agent. Even if an accelerator is added to cause crosslinking, 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. By the way, when the composition of the present invention is coexisting with one type 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. The dispersion becomes 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-hydroxy phenyl urea,
Examples include 3,5-resorcinic acid ethanolamide and 2,4-resorcinic acid ethanolamide.

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 octylamine, tallow anolequinoleamine, dodecynoredimethynoleamine, and alkylpropylenediamine.

2) Nonionic systems; for example, oxyethylene dodecylamine, polyoxyethylene tallow alkylpropylene diamine, polyoxyethylene oleyl ether, polyoxyethylene alkylaryl ether, polyoxyethylene glycol monostearate, sorbitan monostearate, polyoxyethylene Examples include alkylamides 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; for example, dimethylxoalkylbetaine, dimethyl tallow alkylbetaine, etc.

Examples 1 to 10, 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 each Example and Comparative Example.

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. The average value, maximum and minimum values are displayed, and the island bird generation test method... A 25 x 25 x 31 g piece of the composition is heated from room temperature, heated at 120°C for 5 minutes, and then,
Needle end angle 300 obtained by temperature-treating the above composition piece under the same conditions;
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 3 mm/min.

The needle was inserted to a depth such that the distance between its tip and the opposite surface of the composition piece was 1011. After cooling the composition piece into which the needle was inserted, it was left at room temperature for 7 days, and then the voltage generated was measured using the direct-ground method (distance between electrodes 10 m1).In that case, the sample had an initial voltage of 8K,
Thereafter, alternating current voltage is applied using a step-up method that increases the voltage by 2K every 10 minutes, and before increasing the voltage, visually or microscopically observe the sample to see if it is present or not. It was defined as strength. Examples 11 to 20, 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 in a roll mill for 15 minutes.
The mixture was kneaded for minutes to obtain compositions for each example and comparative example.

Claims (1)

[Claims] 1. A polymer composition for electrical insulation, comprising a polyolefin blended with an aromatic para-substituted aldehyde or an aromatic ortho-substituted aldehyde as a voltage stabilizer.