JPS6040648B2 - Manufacturing method of insulated wire for equipment high voltage circuit wiring - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing an insulated wire for wiring equipment high voltage circuits.

For example, for insulated wires for high-voltage circuits such as those used for wiring to cathode ray tube electron guns in televisions, it must have excellent high-temperature dielectric strength characteristics.

'ii} Must have excellent flame retardancy. 'iii} Excellent high-temperature heat deformation resistance.

Rib: Excellent solder resistance. Various characteristics such as these are required.

As an insulated wire that meets this requirement, for example, the insulated wire described in Japanese Patent Publication No. 51-8465 is known.

When this electric wire is required, as shown in the cross-sectional view in Fig. 1, the conductor 6 is coated with a compound mainly composed of polyethylene with a softening point of 105°C or higher, and then cross-linked, and the cross-linked polyethylene coating layer 7 is coated with a compound mainly composed of polyethylene. Furthermore, the insulated wire has a sheath layer 8 formed by coating it with a compound mainly composed of ethylene, vinyl acetate, and vinyl chloride terpolymer.

This insulated wire satisfies the characteristics required for an insulated wire with a temperature rating of 5 to 5 VDC and a temperature rating of 5 to 5 VDC specified in the U.S. UL Standard S Recommended 758, which is applied to the above-mentioned high-voltage circuit wiring. It is said that it passes the particularly strict high voltage power through test in Paragraph 33 and the dry flammability test in Paragraph 3, which will be detailed later.

In short, the insulated wire described in the above publication is thought to have a two-layer structure made of the above-mentioned crosslinked polyethylene and terpolymer, giving the former the characteristics of cut-through properties and the latter of the flame retardant properties. .

However, it is difficult to say that the above-mentioned conventional insulated wires for high voltage circuit wiring can fully meet the requirements.

That is, in the results of the high voltage cut-through test commissioned by the present inventors, the above-mentioned conventional insulated wire did not meet the above-mentioned U.
1 of the rated voltage under the 105o0 temperature condition (rated temperature) according to the L standard. There are cases where insulation breakdown occurs extremely frequently in a short period of less than 7 hours specified by the standards for high-voltage cut-through tests that apply needle-sounding DC electricity, and in extreme cases, 50% of the manufactured insulated wires break down. It has been found that there are cases in which more than 100 defective products are produced, which poses a serious practical problem.

It is expected that the problem of dielectric breakdown (2) can be solved by increasing the thickness of the cross-linked polyethylene layer mentioned above, but tests on this have shown that dielectric breakdown will occur unless the increase reaches approximately 100%. This problem is not solved, and on the other hand, the increase in the thickness of the coating layer increases the space required for wiring and increases the amount of combustible material, which is not desirable. Here, the inventors of the present invention should take a closer look at this problem.As a result of intensive studies, it was found that when forming an insulating layer, a polyolefin mainly composed of polyethylene having a softening point of 10g0 or more and a polyolefin of 100 parts by weight of the polyolefin, 0. 2 to 2 parts by weight of amine and 0.2 to 1. They found that using a composition containing alcohol in an amount of 100% by weight produced a surprising effect, and completed this invention.

That is, this invention provides a conductor with a softening point of 105°C or higher (AST
MD-1525-58T) based on polyethylene as a main component, and 0.2 to 2 parts by weight of amine and
．． 2-1. A crosslinked polyolefin insulating layer is formed by extrusion coating a composition containing alcohol in an amount of parts by weight of This is a method of manufacturing an insulated wire for wiring high voltage circuits of equipment, characterized by providing the following steps.

The reason why the insulated wire obtained by the present invention solves the above problems, such as exhibiting good characteristics in the high voltage cut-through test mentioned above, is not necessarily clear, but the polyolefin coating layer contains amines and alcohols. Due to the presence of the compound, when the polyolefin is crosslinked by radiation irradiation, the compound reduces the accumulation of charge in the coating layer, and exhibits the effect that a high crosslinking effect can be obtained with a relatively small dose of radiation, This is presumed to be one of the causes of the superior trial effect. However, as mentioned above, it cannot be said that this improvement in high-voltage cut-through performance is necessarily achieved by simply reducing charge accumulation. For some reason that cannot be determined clearly, it can be assumed that this material is extremely effective in preventing dielectric breakdown under the conditions of a high voltage cut-through test, that is, under high temperature and strained conditions.

The polyolefin mainly composed of polyethylene with a softening point of 105 oo or higher used in this invention is AS
So-called medium-density and high-density polyethylene alone, or polyethylene or ethylene containing 5% by weight or more of these polyethylenes and the remainder having a softening point of less than 105°C as measured by TMD-1525-58T. and other olefin monomers such as pinyl acetate, ethyl acrylate, propylene, etc., are included.

The amine in the present invention has a basicity of 9 pKb.
．． 5 or less, and generally the XR. -N Buddha
.....'1} Primary, secondary and tertiary amines, etc.

In the formula, XR, YR2, and 3 are an alkyl group, an alkenyl group, and an allyl group, respectively. In the above case, ×=Y=Z=
In the case of hydrogen (hydrogen), the amine in the present invention is ×
, Y, and Z further substituted with a hydroxyl group or a phenyl group.

Representative examples of such amines include propylamine, n-hexylamine, 2-ethylhexylamine, n-heptylamine, n-octylamine, laurylamine, di-n-propylamine, di-n-hexylamine, di-n-octylamine, and tri-n-propylamine. C3 to C,2 primary, secondary, and tertiary alkylamines, diamines such as ethylenediamine, N-ethylethylenediamine, NN'-diethylethylenediamine, trimethylenediamine, and 1,4-diaminobutane;
Examples include aromatic amines such as aniline, P-phenylenediamine, and NN-jethyl-o-toluidine, and alcohol amines such as monoethanolamine, diethanolamine, and triethanolamine.

In addition, alcohol in the present invention refers to monovalent, divalent, trivalent,
It refers to aliphatic alcohols with a melting point of 50°C or lower and a boiling point of 13,000 or higher, specifically n-amyl alcohol, ISO-amyl alcohol, n-hexyl alcohol, n-heptyl alcohol, n-heptyl alcohol, - Monohydric alcohols such as octyl alcohol, ethylene glycol, propylene glycol, 1,3-pro/gundiol, 1,3-butanediol, 2,4-pentanediol, 1,4-butanediol, 1,4-bentane Examples include diol, 1,6-hexanediol, 1,5-bentanediol, and the like.

In the method of the present invention, it is necessary to add the amine and alcohol to the insulating layer in advance in order to form the crosslinked polyolefin insulating layer containing the above-mentioned amine and alcohol. A method in which the molded product obtained by melting and mixing polyolefin and alcohol is brought into contact with amine in a gas or liquid phase, or by melt-mixing the polyolefin, alcohol, and amine using an extruder or heated roll, etc., and molding the product. method is possible.

In any case, in order to obtain the effects of the present invention, it is necessary to uniformly diffuse or disperse the amine and alcohol in the insulating layer, and generally the amine and alcohol are applied to the material forming the insulating layer using a hot roll or the like. It is desirable that the amine be uniformly dispersed in the molding material, and in this sense, it is generally preferable to use an amine having a boiling point higher than the molding temperature.
Furthermore, it is generally known that when a substance having a high melting point is mixed into a polyolefin molded body, internal crystallization occurs in the molded body, and this may cause a decrease in high voltage cut-through resistance. Based on this knowledge, in the present invention, it is desirable to use an amine having a melting point of 50 qC or less.

In the present invention, when forming the insulating layer, the amine and alcohol represented above are uniformly dispersed in the polyolefin forming the insulating layer. The amount of amine added is 2 parts by weight per 10 parts by weight of polyolefin.
It is not more than 0.1 to 0.5 parts by weight, preferably 0.1 to 0.5 parts by weight. In the present invention, the amount of amine added is preferably limited to 0.1 to 0.5 parts by weight, because if it is less than 0.1 part by weight, the effect of the present invention will not be sufficiently exhibited.
If the amount is 5 parts or more, a sufficient effect is shown in improving high voltage cut-through resistance, but the crosslinking reaction is significantly inhibited in the initial stage. The amount of alcohol used in combination with the above amine is 0.2 to 1 part by weight, preferably 0.2 to 1 part by weight.
．． It is 5 to 1.0 parts by weight.

This is because if it is less than 0.2 parts by weight, the interaction with Amiso is not effective, and 1. If the amount exceeds , the increase in effectiveness will not be significant. In addition, when forming the polyolefin insulating layer in the present invention, conventionally known crosslinking accelerators such as diallyl maleate, ethylene glycol dimethacrylate, triallyl cyanurate, dipropargyl monoallyl cyanurate, dipropargyl maleate, Dipropargyl succinate and others may also be used.

To crosslink the above-mentioned polyolefin, an electron beam from an electron beam accelerator is generally used from an industrial standpoint, and the irradiation dose is preferably 5 to 4 rad.

Furthermore, in the present invention, anti-aging agents, lubricants, colorants, ultraviolet absorbers, copper damage inhibitors, etc. may be mixed with the polyolefin in order to further impart desired properties. Next, the protective sheath layer provided on the insulating layer in the present invention can be selected from various types depending on the degree of flame retardation required for the insulated wire, but for example, polychloride which passes the vertical combustion test of the UL standard is used. Vinyl, flame-retardant chlorinated polyethylene resin, calcined ethylene, vinyl acetate, vinyl chloride terpolymer resin, and the like are preferred.

Although it is not preferable to mix a scale retardant into polyolefin because it reduces the withstand voltage characteristics, the crosslinked polyolefin insulating layer formed on the conductor by the method of the present invention itself has high high voltage breakdown characteristics. Therefore, in order to improve the flame retardancy of the obtained insulated wire, if necessary, and to facilitate cost-effective selection of a flame-retardant outer sheath material, a flame retardant may be added to the insulating layer. There is no practical problem even if a curing agent is added.

Elutriation agents used for polyolefins for this purpose include mixtures of organic halides, such as dechlorane, decabromodiphenyl ether, bisguanidium tetrabromophthalate, hexabromobenzene, etc., with antimony trioxide, zirconium oxide, or , hydrated inorganic compounds such as hydrated alumina are used, and their blending amounts are determined depending on the desired degree of bonito burn.

However, when imparting flame retardancy to the polyolefin layer, it is necessary to take care not to reduce the high-pressure cut-through properties mentioned above, and specifically, the amount of halogen is preferably 15% by weight or less based on the resin content. .

When using a hydrated inorganic compound such as hydrated alumina, the amount is preferably 5 parts by weight or less per 10 parts by weight of the resin.

It is desirable to crosslink the Takigami self-protective sheath layer as necessary, thereby improving the heat deformation resistance of the insulated wire.

As will be clear from the above description and the examples described later, this invention is a simple means of mixing amine and alcohol into polyolefin for forming an insulating layer, and it is a simple means of mixing an amine and an alcohol into polyolefin to form an insulating layer. The problem has been significantly improved, and its industrial value is enormous.

EXAMPLES The effects of the present invention will be specifically explained below with reference to Examples and Comparative Examples.

Examples 1 to 4 and Comparative Examples 1 to 6 Various amines and alcohols as shown in Table 1 were added to high-density polyethylene with a softening point of 105 oo or higher on a conductor (0.754 wire, tin-plated mild steel wire). Each of the blended compositions was extrusion coated using a conventional extruder with L/D=22 and D=65 to give a coating thickness of 0.5 mm.

In addition, each amine and alcohol were blended into the base polyethylene using an open roll in a conventional manner.

Each of the insulated wires thus obtained was irradiated with an electron beam using a conventional electron beam irradiation method to crosslink the polyethylene insulating layer.
Next, on the crosslinked polyethylene insulation layer of each insulated wire thus obtained, an ethylene-vinyl acetate-vinyl chloride terpolymer (compound 0.68%, manufactured by Sumitomo Bakelite) was applied to
9 arcs) were extrusion coated. For comparison, insulated wires were made in the same manner as in the example except that no amine or alcohol was blended into the polyethylene for forming the insulating layer, and the coating thickness of the unblended polyethylene was varied.

Ten samples were appropriately taken from the length of each insulated wire 1000 obtained above, and various characteristics were investigated.

The obtained results are also listed in Table 1. Table 1 (All values in the table are parts by weight) (Note) - In the table, polyethylene marked with a gi...high-density polyethylene with a density of 0.950 and a softening point of 124.0 * polyethylene marked with a density of 0 .945, high-voltage cut-through test for high-density polyethylene with a softening point of 120.0... As shown in Figure 2, the insulated wire for testing (2) was strung across the metal port steel (1), and a load of 900 g (3 ) to both ends of the wire and connect the chamber (
4) Hold the tip of the channel steel (1) in the
While forcibly deforming the specimen with a radius of curvature of 30 Kv DC for 7 hours from the power source (5), it is examined whether or not dielectric breakdown occurs.

・Heat deformation rate of insulator layer...136, 500g,
According to JISC3005 - Soldering resistance of insulator layer...
- According to the regulations of MIL-W-16978/D.・UL Vertical Combustion Test...The test insulated wire is placed vertically and burned from the bottom with a gas burner. Kare Roku 3 Test that does not always ignite. As is clear from the results in the table above, it is clear that the products manufactured by the present invention are significantly superior in high-pressure cut-through characteristics compared to comparative products. In Comparative Example 1, the insulation thickness was increased to improve high voltage cut-through characteristics, and although a slight improvement was observed, on the other hand, because the flammable insulation layer was thickened, the flame retardant sex is greatly reduced,
Moreover, this is undesirable because it causes an increase in flea on the obtained insulated wire.

Moreover, Comparative Examples 4 to 6 and Examples 2 to 4 are examples in which a typical crosslinking accelerator was used in combination. Examples 5 to 7 Insulating compositions shown in Table 2 and ethylene-vinyl acetate-vinyl chloride terpolymer (compound o9 arc manufactured by Sumitomo Bakelite) were used as the protective sheath material, and the same method as in Example 1 was carried out. Insulator layer 0.5m' skin, outer sheath thickness 0.68
An insulated wire with a structure of 'm was made.

Various properties of each insulated wire thus obtained were investigated.

The obtained results are also listed in Table 2. Table 2 (The numbers in the table are parts by weight) (Note) In the table, (1), (2), (3), (4), (5)
Examples 8 to 11 and Comparative Examples 7 to 9 are the same as those listed in Table 1.The compositions shown in Table 3 were used as the insulating material, and the polyvinyl chloride resin compositions shown in Table 4 were used as the sheath layer material. An insulated wire was made in the same manner as in Example 1, and various characteristics were investigated in the same manner as in Example 1.

The obtained results are also listed in Table 3. Table 3 (Numbers in the table are parts by weight) (Note) (1) in the table is the same as the * mark in Table 1, and (2-, (5) are the same as those in the first notation.EVA... ..Ethylene-vinyl acetate copolymer, vinegar heat content 19% by weight, MI: 2
．． 5.EPR. ...Ethylene propylene copolymer
Propylene content 50% by weight, Mooney viscosity MLI+4
(100-○)=40・Dechloran Plus 25・・・・
Product name of Fukka Co., Ltd. in the United States, chlorine-based flame retardant (chlorine content: 65
Weight%)・DBDE・・・・Decabromodiphenyl ether, brominated retardant (bromine content 83% by weight) Table 4 @
In the table *... Nippon Zeon Straight Vinyl Chloride Polymer 101EP As is clear from Table 3, an inexpensive vinyl chloride resin composition can be used as an external sheath material by adding a scale retardant to the insulator layer material. Although the insulated wire obtained by using the flame retardant was able to maintain the specified flame retardancy, the high voltage cut-through characteristics mentioned above were significantly lower in the comparative product, whereas the product manufactured using the method of the present invention was Except for Example 9 where the amount added was excessive, sufficient performance was maintained.

Furthermore, as shown in Comparative Example 9, an insulated wire in which the insulator layer is made of polyethylene that is not flame retardant and the outer sheath layer material is made of a polyvinyl chloride resin composition has insufficient flame retardancy. In other words, according to the method of the present invention, effects such as an inexpensive polyvinyl chloride resin composition can be used as the material for the outer sheath layer can be expected by making the material for forming the insulating layer flame retardant, if necessary.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional explanatory diagram of an insulated wire obtained by the method of the present invention, and FIG. 2 is a schematic diagram of a test device for explaining a high-voltage cut-through test method for an insulated wire. 1...Metal channel steel, 2...Insulated wire for testing,
3... Weight, 4... Constant overflow tank, 5...
...DC power supply, 6...Conductor, 7...
Insulator layer, 8...Sheath layer. Figure 1 Figure 2

Claims (1)

[Claims] 1 The main component of the conductor has a softening point of 105°C or higher (AS
TMD-1525-58T) per 100 parts by weight of polyolefin, 2 parts by weight or less of amine and 0.2 to 1
．． After extrusion coating a composition containing 0 parts by weight of alcohol and irradiating it with radiation to form a crosslinked polyolefin insulation layer, a protective sheath layer made of a flame-retardant synthetic resin composition is formed on the crosslinked polyolefin insulation layer. 1. A method of manufacturing an insulated wire for equipment high voltage circuit wiring, comprising: