JPH038043B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to synthetic resin-coated lead wires used as lead wires of electrical equipment, such as stators and power transformers, which are impregnated with a solvent-free varnish. [Technical background of the invention and its problems] Synthetic resin-coated lead wires are generally used for the output wires of various electrical devices, but these can be broadly classified into vinyl chloride resin-coated lead wires (hereinafter referred to as PVC lead wires). There are two types: CPE lead wires (hereinafter referred to as CPE lead wires) and cross-linked polyethylene coated lead wires (hereinafter referred to as CPE lead wires). On the other hand, among electrical equipment such as stators and power transformers, after connecting the lead wires to the main body, the entire body is usually immersed in solvent-free insulating varnish, and then the varnish that has adhered to it is heated and hardened to insulate it. It is being said. As this solvent-free varnish,
Generally, a curing agent such as an organic peroxide is added to a base material such as an unsaturated polyester, and a reactive diluent such as a styrene monomer is blended with this. However, when PVC lead wires are used as lead wires for transformers etc. that are insulated with such solvent-free varnish, the characteristics of the polyvinyl chloride resin coating may deteriorate for the following reasons. There was a problem. In other words, in the PVC lead wire,
Since the plasticizer contained in the coating is extracted by the styrene monomer in the insulating varnish, there is a problem that the coating becomes brittle and is prone to cracking, especially when external force is applied in cold weather. Ta. In order to avoid such problems, various methods have been adopted when using PVC lead wires, such as shortening the insulating varnish treatment time and softening the cured varnish, but these methods do not completely degrade the coating. At present, we have not yet reached the point of preventing this. In addition, the heat-resistant temperature of PVC lead wires is
The drawback was that the temperature was as low as 105°C, which limited the types of electrical equipment that could be used. On the other hand, CPE lead wire has a heat resistance temperature of 120℃.
Moreover, since the coating does not contain a plasticizer, it has the advantage that the properties do not deteriorate even when subjected to the above-mentioned insulating varnish treatment. However, such a CPE lead wire has a drawback in that when the above-mentioned varnish adheres to the coated surface, the varnish does not completely harden even if sufficient heating and drying is performed. The reason for this is presumed to be that the coating contains components that inhibit the curing of the varnish, such as anti-aging agents. For this reason, despite having the above-mentioned good characteristics, CPE lead wires are not often used in electrical equipment treated with solvent-free varnish. [Object of the Invention] The present invention was made in order to solve the above-mentioned conventional difficulties, and its purpose is to provide a lead wire for electrical equipment that has a high heat resistance temperature and does not inhibit the hardening of the insulating varnish. do. [Summary of the Invention] The lead wire for electrical equipment of the present invention is a lead wire used as an output wire of an electrical equipment that is impregnated with a solvent-free varnish, and includes a cross-linked polyethylene insulating layer and a resin 100% by weight on a conductor. A synthetic resin coating layer containing 0.2 to 3 parts by weight of an organic peroxide per 10% of the organic peroxide is sequentially provided, and the synthetic resin coating layer contains 100% of the synthetic resin.
It is characterized in that the metal alcoholate compound or metal alkylate compound is contained in a ratio of 0.05 to 5 parts by weight based on the weight part. In the lead wire of the present invention, the lower crosslinked polyethylene insulating layer is formed by extruding ordinary low-density or medium-density polyethylene on the conductor and then irradiating it with electron beams, or by applying a low-density or medium-density polyethylene insulating layer containing a crosslinking agent. It is formed by extrusion coating a density polyethylene-based composition onto a conductor and heating it to a temperature above the decomposition temperature of the crosslinking agent. In addition, in the present invention, the synthetic resin coating layer containing a metal alcoholate compound or metal chelate compound provided on the crosslinked polyethylene insulating layer is a synthetic resin coating layer containing Ti, Al, etc., added to 100 parts by weight of a resin such as unsaturated polyester or urethane-modified acrylic. 0.05 to 5 parts by weight, preferably 0.1 to 2 parts by weight, of metal alcoholates such as ethanol, propyl alcohol, butyl alcohol, or chelate compounds such as acetylacetone, and if necessary, styrene, methacrylic, etc. are added as viscosity modifiers. It is formed by applying a resin composition obtained by adding a monomer and adding 0.2 to 3 parts by weight of an organic peroxide as a curing agent, and curing it by heating. If the metal alcoholate or metal chelate compound is less than 0.05 parts by weight, the curing of the resin in the synthetic resin coating layer will be inhibited by the anti-aging agent contained in the crosslinked polyethylene, and if it exceeds 5 parts by weight, the coating resin composition will become unstable. This is not desirable as it will result in poor sex. The mechanism by which metal alcoholates or metal chelate compounds prevent the inhibitory effect of anti-aging agents is not necessarily clear, but compounds that are usually added as anti-aging agents for cross-linked polyethylene, namely phenols that add hydrogen to peroxy radicals and oxy radicals. hydroxyl derivatives, amines, or sulfur and phosphorus compounds that convert hydroperoxides into stable hydroxides, which mask the curing agent action of organic peroxides. It is thought to have an indirect curing effect by fully exhibiting catalytic action. Such an effect of masking the anti-aging agent in cross-linked polyethylene is also recognized by the addition of amino resin, and was disclosed in Japanese Patent Application No. 187508/1983 (Japanese Patent Application No. 78406/1983); The content is presumed to be that the amino resin has an onium action of nitrogen, which is different from the metal chelating action in metal alcoholates or metal chelate compounds. The coating is carried out by applying the composition onto the insulating layer of the crosslinked polyethylene coating using a suitable coating device and removing excess composition with a die. The coating thickness of the synthetic resin coating layer containing a metal alcoholate or a metal chelate compound may be sufficient as long as it is sufficient to separate the crosslinked polyethylene insulation coating and the solvent-free varnish, and a thickness of about several micrometers to several hundred micrometers is sufficient. . [Embodiments of the Invention] Examples will be described below with reference to the drawings. Example 1 As shown in Figure 1, the conductor diameter is 1 mm and the insulation layer thickness is 1 mm.
A cross-linked polyethylene insulated wire 1 is passed through a coating bath 3 containing a resin composition 2 containing 100 parts by weight of unsaturated polyester, 1 part by weight of aluminum trisacetylacetonate, and 2 parts by weight of benzoyl peroxide, and is squeezed with a die 4 to remove excessive squeezing. After removing the composition to form a coating film with a thickness of approximately 0.1 mm, this was passed through a drying oven 5 at 120° C. to be completely cured, and then wound onto a drum 6. The unsaturated polyester used here was 112 parts by weight of soybean oil and glycerin.
18 parts by weight of lead monoxide, 0.04 parts by weight of lead monoxide were added, and the transesterification reaction was carried out at 240°C for about 1 hour under a stream of nitrogen gas. After cooling, 86 parts by weight of maleic anhydride,
Add 91 parts by weight of isophthalic acid and 91 parts by weight of ethylene glycol and react at 200°C until the acid value of the free acid is 10.
Dehydrate under reduced pressure until 0.1 parts by weight of hydroquinone at 120℃, 100 parts by weight of styrene at 100℃, 1.5
It was obtained by adding parts by weight of manganese naphthenate solution. Next, the effect on the hardenability of the insulation treatment varnish for the lead wire thus obtained was investigated as follows. That is, the lead wires obtained in the examples and three types of wires, conventional PVC lead wires and CPE lead wires, were added to 100 parts by weight of the unsaturated polyester as a curing agent, and 1,1-di-t-butyl permeate was added as a curing agent. After immersing for 10 minutes in an unsaturated polyester varnish containing 1 part by weight of oxy-3,3,5-trimethylcyclohexane,
After drying by heating for a period of time, the hardening state of the attached varnish was observed. The results are shown in Table 1.

[Table] ×...High viscosity, △...Slightly sticky ○...Sufficiently cured without sticking Also, Examples and Comparative Example 1 (PVC lead wire)
The cracking resistance at low temperatures was tested using test pieces prepared by the following method. That is, as shown in Figs. 2 and 3, prepare 20 lead wires 7 each cut to a certain length, and bend the central portions of these lead wires so as to sandwich both sides of a 1 mm thick iron plate 8. After adhesively fixing both ends of the lead wire 7 to the surface of the iron plate 8 using adhesive tape 9, another iron plate 10 was applied to one side of the lead wire 7, and the iron plates 8 and 10 were fixed with a clip. Next, the whole was immersed in the aforementioned unsaturated polyester varnish for 10 minutes, and then heated at 110° C. for 3 hours to harden the varnish to prepare a test sample. Each of the test samples obtained was placed in a -10°C low-temperature bath for 1 hour, then taken out, the lead wires 7 were immediately stretched out in a straight line, and the number of lead wires with cracks in the coating was counted. Table 2 shows the number of cracks in the 20 samples.

〔Effect of the invention〕

As is clear from the above examples, the lead wire of the present invention has a cross-linked polyethylene insulation coating, so it has a higher heat resistance than conventional PVC lead wires, has excellent styrene resistance, and has excellent resistance to styrene when bent at low temperatures. No cracks will occur in the coating. Furthermore, since a thin layer of synthetic resin containing a metal alcoholate or metal chelate compound is provided on the surface of the cross-linked polyethylene coating, even if insulation treatment varnish adheres to the coating surface, it will not inhibit the curing of the varnish. It is suitable as a lead wire for electrical equipment such as a transformer whose entire body is impregnated with varnish.

[Brief explanation of drawings]

FIG. 1 is an explanatory view showing the manufacturing process of the lead wire of the present invention, and FIGS. 2 and 3 are a cross-sectional view and a plan view of a test piece for examining cracking resistance at low temperatures. 1...Crosslinked polyethylene insulated wire, 2...Synthetic resin, 4...Dice, 5...Drying oven, 6...Drum, 7...Lead wire, 8, 10...Iron plate, 9...
Adhesive tape.

Claims (1)

[Claims] 1. In a lead wire used as an outlet wire for electrical equipment that is impregnated with a solvent-free varnish, a crosslinked polyethylene insulating layer and 0.2 to 3 parts by weight of organic peroxide are added to 100 parts by weight of the resin on the conductor. The synthetic resin coating layer is characterized in that the synthetic resin coating layer contains a metal alcoholate compound or a metal alkylate compound at a ratio of 0.05 to 5 parts by weight per 100 parts by weight of the synthetic resin. Lead wire for electrical equipment.