JPH0612933A - Manufacture of insulated electric wire - Google Patents

Abstract

PURPOSE:To provide an insulated electric wire where an insulating coating film by itself has remarkably improved lubricity by applying an insulating coating material where a compound including an organic lubricant and an alcohol hydroxyl group is added into a polyamide imide resin to a conductor, followed by baking. CONSTITUTION:0.1-10 pts.wt. of an organic lubricant (such as carnauba wax, dimethyl silicone, and polytetrafluoroethylene) and 5-150 pts.wt. of a compound containing an alcohol hydroxyl group (such as methanol, ethylene glycol, and glycerine) are added into 100 pts.wt. of a polyamide imide resin (in a solid state), thus preparing an insulating coating material. The insulating coating material is applied to a conductor (such as a steel wire) directly or via an insulating coating film (such as a polyurethane resin), followed by baking. Consequently, it is possible to obtain an insulated electric wire where the insulating coating film by itself has remarkably improved lubricity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an insulated wire used for a motor, a transformer, etc., which has excellent lubricity.

[0002]

2. Description of the Related Art In recent years, electric appliances have been reduced in size and improved in performance, and the insulated electric wires used therein have been wound more densely. In addition, the winding speed of the insulated wire has been increased to improve productivity. Along with these, the film of the insulated wire is more easily damaged than before, but attempts have been made to improve the lubricity of the insulated wire in order to prevent damage to the insulating film.

The insulating film is formed by applying an insulating coating material on the conductor and baking it. In order to improve the lubricity of the insulated wire, wax such as liquid paraffin or solid paraffin is generally applied on the insulating film to form a lubricating film. It has also been proposed to form a low molecular weight polypropylene film on an insulating film (Japanese Patent Publication No. 58-8).
No. 05). However, in the field of refrigerators, compressor motors of air conditioners, etc., the application of waxes as described above is practically problematic and cannot be used.

Therefore, instead of forming a lubricating film,
Studies are underway to improve the lubricity of the insulating film itself. Specifically, it has been proposed to use an insulating material in which a low molecular weight fluororesin or a lubricant such as wax or low molecular weight polyethylene is mixed (for example, JP-B-54-386).
No. 16, JP-B 57-45002, JP-B 51-28
No. 420). However, although these conventional attempts can improve the lubricity of the insulating film to some extent, they are still insufficient, and further improvement is required.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing an insulated wire in which the lubricity of the insulating film itself is significantly improved. As a result of earnest studies, the present inventors have prepared an insulating coating material by adding an organic lubricant for imparting lubricity to an insulating coating material containing a polyamide-imide resin and further adding a compound having an alcoholic hydroxyl group. When this insulating paint was applied / baked directly on the conductor or through another insulating film, the insulating paint containing the polyamide-imide resin was used as well as the organic lubricant in the insulating paint containing the polyamide-imide resin. It was found that an insulated electric wire exhibiting remarkably excellent lubricity can be obtained as compared with the case of using an insulating coating added with, and the present invention has been completed based on the finding.

[0006]

Thus, according to the present invention, an insulating coating material containing a polyamide-imide resin, an organic lubricant, and a compound having an alcoholic hydroxyl group is applied to a conductor directly or through another insulating film. Provided is a method for manufacturing an insulated wire, which is characterized by baking.

The present invention will be described in detail below. Polyamideimide resin used in the present invention is usually produced from aromatic tricarboxylic acid anhydride and aromatic diamine,
Structurally, it is a resin having a form containing alternating imide groups and amide groups.

Typical methods for producing a polyamide-imide resin include the acid chloride method and the isocyanate method, both of which activate either monomer in order to compensate for the slow reaction between the aromatic diamine and the carboxyl group. It is converted to a derivative and polycondensed. On the other hand, recently, a direct polycondensation method has been developed in which an aromatic tricarboxylic acid anhydride and an aromatic diamine are directly polycondensed in the presence of a dehydration catalyst.
In the present invention, a polyamide-imide resin produced by any production method can be used. Further, an aliphatic tricarboxylic acid anhydride or an aliphatic diamine may be used.

In the acid chloride method, the carboxyl group of an aromatic tricarboxylic acid anhydride is usually converted into a chloroformyl group, and a rapid reaction between this and an amino group is used. Part of the acid chloride of the tricarboxylic acid anhydride may be replaced with at least one dicarboxylic acid dichloride, at least one tetracarboxylic acid dianhydride, or at least one dicarboxylic acid dichloride and at least one tetracarboxylic acid dianhydride. Good. Further, a part of the diamine may be replaced with at least one tetramine, or at least one triamine and at least one tetramine.

Specific examples of the acid chloride of tricarboxylic acid anhydride include 4-acid chloride of trimellitic acid anhydride. Specific examples of the dicarboxylic acid dichloride include terephthalic acid dichloride, isophthalic acid dichloride, adipic acid dichloride and the like.

Specific examples of the diamine include 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether and m-phenylenediamine. Specific examples of triamine include 3,4,4'-triaminodiphenyl ether. Examples of tetramines include:
3,3 ', 4,4'-tetraaminodiphenyl ether and the like.

In the isocyanate method, the amino group of the aromatic diamine is usually converted into an isocyanate group, and the rapid reaction between this and the carboxyl group is utilized. Part of the tricarboxylic acid anhydride may be replaced with at least one dicarboxylic acid, at least one tetracarboxylic dianhydride, or at least one dicarboxylic acid and at least one tetracarboxylic dianhydride. Also, a part of the diisocyanate may be replaced with at least one trivalent or higher polyisocyanate.

Specific examples of the tricarboxylic acid anhydride include:
Examples include trimellitic anhydride. Specific examples of the dicarboxylic acid include isophthalic acid, terephthalic acid, adipic acid and the like. Specific examples of the tetracarboxylic dianhydride,
Examples include pyromellitic dianhydride and benzophenone tetracarboxylic dianhydride.

Specific examples of the diisocyanate include diphenylmethane-4,4'-diisocyanate, diphenylether-4,4'-diisocyanate, tolylene diisocyanate, xylylene diisocyanate and hexamethylene diisocyanate.

Examples of polyisocyanates include polymethylene polyphenylene polyisocyanate. Among them, it is preferable to use a polyamide-imide resin obtained by reacting an aromatic tricarboxylic acid anhydride or its derivative with an aromatic diisocyanate, because the heat resistance characteristic of the polyamide-imide resin can be further exhibited. Furthermore, among the polyamide-imide resins, it is preferable to use a polyamide-imide resin having a molecular weight of 0.2 to 1 in terms of reduced specific viscosity, because the obtained insulated wire has good properties and good workability during the production of the insulated wire.

The organic lubricant used in the present invention is an organic material-based lubricant such as wax, silicone, or fluororesin, and the following can be preferably used as specific examples.
Specific examples of waxes include plant waxes such as candelilla wax, carnauba wax, rice wax, and wax wax; animal waxes such as beeswax, lanolin, and whale wax; mineral waxes such as montan wax ozokerite and ceresin; Petroleum waxes such as paraffin wax and microcrystalline wax; synthetic hydrocarbons such as Fischer-Tropsch wax and polyethylene wax; modified waxes such as montan wax derivatives and paraffin wax derivatives.

Specific examples of silicones include polyorganosiloxanes such as dimethyl silicone, diethyl silicone and diphenyl silicone. Specific examples of the fluororesin include polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer and the like.

The compound having an alcoholic hydroxyl group used in the present invention is a compound having one or more alcoholic hydroxyl groups in the molecular structure, and includes the following. Examples of the compound having one alcoholic hydroxyl group include alcohols such as methanol, ethanol, n-propanol, isopropanol, s-butanol, t-butanol, n-hexanol, and cyclohexanol; methyl cellosolve, cellosolve, propyl cellosolve, phenyl cellosolve. , Methyl carbitol, carbitol, propyl carbitol, phenyl carbitol, and other cellosolves.

Examples of the compound having two alcoholic hydroxyl groups include ethylene glycol, diethylene glycol, triethyl glycol, propylene glycol,
Examples thereof include glycols such as dipropylene glycol and butylene glycol. Examples of the compound having three or more alcoholic hydroxyl groups include glycerin, trimethylolpropane, pentatritol and the like. Among these, use of a compound having two or more alcoholic hydroxyl groups is preferable because the effect of lubricity is large, and a compound having two alcoholic hydroxyl groups is more preferable.

As the solvent used for the insulating coating containing the polyamideimide resin, the organic lubricant and the compound having an alcoholic hydroxyl group, N-methyl-2-pyrrolidone, dimethylacetamide, which is used as a solvent for the polyamideimide resin, Diluents such as dimethylformamide and solvent naphtha, toluene, xylene are preferable, but phenol, cresol, cyclohexanone, methyl ethyl ketone, ethyl acetate, tetrahydrofuran, nitrobenzene, dioxane, furfural, sulfolane, dimethyl sulfoxide, pyridine used in ordinary baking paints are preferable. , Aniline, diethyl carbonate, etc. may be used or partly added.

Further, thermoplastic resins such as polyvinyl formal, polyamide, polyester, polyurethane, polyether, polysulfone, polyether sulfone, and polyetherimide; melamine resin, phenol resin, polyester, etc. to the extent that the characteristics of the present invention are not impaired. Thermoplastic resins such as polyurethane, polyester imide, polyester amide imide, polyimide, hydantoin;
Fillers, pigments, dyes, surfactants, antioxidants and the like may be added as appropriate.

The use ratios of the polyamide-imide resin, the organic lubricant, and the compound having an alcoholic hydroxyl group are appropriately selected depending on the desired degree of lubricity, the type of organic lubricant, the type of compound having an alcoholic hydroxyl group, and the like. Although it can be changed, the organic lubricant is usually used in an amount of 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, and a compound having an alcoholic hydroxyl group with respect to 100 parts by weight of the polyamide-imide resin (solid content). Usually 5 to 150 parts by weight, preferably 20 to 100
It is desirable to use in the range of parts by weight.

The insulating paint containing the polyamide-imide resin of the present invention, an organic lubricant and a compound having an alcoholic hydroxyl group can be directly applied / baked on a conductor, but another insulating paint can be applied on the conductor. After baking, the insulating coating material of the present invention can be applied and baked on it.

Other insulating paints include polyurethane resin, polyvinyl formal resin, epoxy resin, polyamide resin, polyester resin, THEIC [Tris (2
-Hydroxyethyl) isocyanurate] modified polyester resin, ester imide resin, ester amide imide resin, polyimide resin, polyhydantoin resin, polysulfone resin, polyether sulfone resin, polyetherimide resin, etc. Anything can be used.

As the conductor, various kinds of wires such as a copper wire which is usually used can be used, and the shape thereof can be a desired shape such as a round wire or a rectangular wire, and the size is not limited.
Regarding the conditions for coating / baking, the thickness of the film, etc., it is possible to adopt the usual conditions for producing an insulated wire using a polyamide-imide varnish.

[0026]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In the following examples and the like, “parts” means “parts by weight” unless otherwise specified.

[Example 1] Polyamideimide insulating paint (HI-400 manufactured by Hitachi Chemical Co., Ltd .: hereinafter abbreviated as HI-400) to 100 parts of solid content, 2 parts of carnauba wax,
50 parts butanediol were added and mixed. Furnace temperature 400 ℃
In a baking oven, a polyester imide insulating paint (Isomid 40H manufactured by Nichitsu Schenectady) was applied and baked on a 0.80 mmφ copper conductor to a film thickness of 0.025 mm, and then the above carnauba wax and butanediol were added. Polyamide-imide insulating paint containing the above is used to obtain a film thickness of 0.
It was applied and baked to have a thickness of 005 mm. Table 1 shows the static friction coefficient and general characteristics of the obtained insulated wire.

Comparative Example 1 HI-400 solid content 100
An insulated wire was obtained in the same manner as in Example 1 except that 2 parts of carnauba wax was blended in each part. Table 1 shows the static friction coefficient and general characteristics of the obtained insulated wire.

[Comparative Examples 2, 3 and Examples 2-5] Instead of butanediol, dimethylformamide (DMF) was used.
(Comparative Example 2), cyclohexanone (Comparative Example 3), n-butanol (Example 2), propylene glycol (Example 3), dipropylene glycol (Example 4), or diethylene glycol monomethyl ether (Example 5). An insulated wire was obtained in the same manner as in Example 1 except that was used. Table 1 shows the static friction coefficient and general characteristics of the obtained insulated wire.

Examples 6-8 Microcrostaline wax (Example 6), Hoechst wax E (Example 7), or a molecular weight of about 200 instead of carnauba wax.
An insulated wire was obtained in the same manner as in Example 1 except that low molecular weight polyethylene of 0 (Example 8) was used. Table 1 shows the static friction coefficient and general characteristics of the obtained insulated wire.

[0031]

[Table 1]

(Footnote) (1) The static friction coefficient was measured with a tilt needle type static friction coefficient measuring device (manufactured by Toyo Seiki Co., Ltd.). (2) The general properties other than the above were measured according to the test method for the enamel copper wire specified in JIS C-3003.

[0033]

According to the present invention, it is possible to provide a method for manufacturing an insulated wire in which the lubricity of the insulating film itself is significantly improved as compared with the conventional method. The insulated electric wire according to the manufacturing method of the present invention suppresses damage to the insulating film even by high-density winding or high-speed winding,
Since it can respond to miniaturization and high performance of electric equipment in recent years,
Its industrial value is great.

Claims (1)

[Claims] 1. An insulated wire characterized in that an insulating coating material containing a polyamide-imide resin, an organic lubricant, and a compound having an alcoholic hydroxyl group is applied / baked onto a conductor directly or through another insulating film. Production method.