JPH04245110A - Self-fusible insulative electric wire and coil using the same - Google Patents

Abstract

PURPOSE:To provide a thin fusible layer which is foamed at a predetermined low temperature and enhanced in fusing strength and space factor by forming the fusible layer including a foaming agent and a foaming assistant on the metal conductor via an insulative layer. CONSTITUTION:An insulative layer 2 is formed on a metal conductor 1, and a fusible layer 3 including a foaming agent and a foaming assistant is formed on the layer 2. Such a foaming agent as to be dissolved with application of heat and generate nitrogen gas or carbon dioxide gas is used as the foaming agent to be included, and an azo, nitroso or hydrazide foaming agent is used as an organic foaming agent. A vulcanization accelerator capable of promoting thermal decomposition of the foaming agent, a PVC stabilizer or the like is used as the foaming assistant. Each predetermined quantity of the foaming agent and foaming assistant is dissolved or dispersed in a solution of a fusible resin, thus forming a fusible coating material, which is applied and baked on the layer 2, followed by energization heating or hot-air drying, for foaming the layer 3. Consequently, the fusible layer is foamed at a predetermined low temperature for thinness, thus enhancing fusing strength and a space factor of the conductor.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-bonding insulated wire with excellent melting properties.

0002

2. Description of the Related Art Self-bonding insulated wires have the advantage of shortening the work process because wires can be bonded together without the use of impregnated varnish when making a coil. However, although the use of self-bonding insulated wires is increasing, the following two problems have limited the applications in which they can be used, and only a few of them are still used.

First of all, the most important characteristic of self-bonding insulated wires, the fusing strength, is insufficient. In particular, butyral resins and phenoxy resins, which have poor fluidity during fusion bonding, have a significant lack of fusion bonding strength, and even polyamide resins, which have excellent fluidity, have a problem in that their fusion bonding strength is not sufficient. Further, when the self-bonding insulated wire is formed into a coil, there is a problem in that depending on the shape of the coil, there may be portions with low inter-wire density, resulting in less adhesion between the wires and insufficient fusing force.

The second problem is that because the adhesive layer is thick, the space factor, which represents the ratio of the cross-sectional area of the electric wire to the core of the motor, is small. In recent years, with the miniaturization of equipment, coils and motors have also become smaller, and it is desired to pack more insulated wires into a small space and improve the space factor of the wires. Therefore, it is preferable that the thickness of the fusion layer be as thin as possible without impairing the fusion bonding strength, as this will improve the space factor. However, the thickness of the currently used fusion layer is approximately 1/2 to 1/3 that of the insulating layer, which is very thick, and there is a problem in that the space factor cannot be improved.

[0005]

SUMMARY OF THE INVENTION To address these problems, a self-bonding insulated wire in which the bonding layer foams during bonding has been proposed. When this self-bonding insulated wire is used, the welding layer foams and the thickness of the welding layer increases by two to three times, thereby improving the flowability of the resin and increasing the welding strength. Furthermore, the fusion layer can be made thinner, and the space factor can be improved. However, in the case of fusion bonding by electrical heating, foaming of the fusion layer occurs;
In the case of fusing by hot air drying at around 150°C, a new problem arose that the fusing layer was insufficiently foamed.

[0006]

[Means for Solving the Problems] As a result of intensive studies in order to solve the above problems, the present inventors have found that by adding a foaming aid to the adhesive layer containing a foaming agent, the temperature at around 150° C. We have invented a self-bonding insulated wire whose adhesive layer can be foamed even at low temperatures.

That is, the present invention is a self-bonding insulated wire characterized in that a melting layer containing a foaming agent and a foaming aid is formed on a metal conductor via an insulating layer.

The present invention will be explained in detail below. The foaming aid used in the present invention can be anything that promotes thermal decomposition of the foaming agent, such as vulcanization accelerator, filler, vulcanization accelerator, PVC stabilizer, anti-aging agent, and vulcanizing agent. , urea compounds, etc.

Vulcanization accelerators include guanidine, aldehyde-ammonia, sulfenamide, thiuram, xanthate, aldehyde-amine, thiazole, thiourea, and dithiocarbamate, and fillers include:
Silica, magnesium carbonate, calcium carbonate, magnesium silicate, aluminum carbonate, talc, barium sulfate, aluminum sulfate, calcium sulfate, etc. are used as vulcanization accelerators, zinc white, activated zinc white, zinc carbonate, magnesium oxide, monoxide, etc. Lead, basic lead carbonate, calcium hydroxide,
Stearic acid, oleic acid, lauric acid, diethylene glycol, di-n-butylamine, dicyclohexylamine, diethanolamine, organic amines, etc.
Stabilizers include tribasic lead sulfate, dibutyltin dilaurate, dibutyltin dimalate, zinc stearate, cadmium stearate, barium stearate, calcium stearate, etc. Anti-aging stabilizers include naphthylamine type, diphenylamine type, P-phenylene type, Vulcanizing agents include quinoline, monophenol, polyphenol, thiobisphenol, and phosphite esters.
Examples include ammonium sulfur benzoate.

[0010] Other chemicals include phthalic anhydride, salicylic acid, benzoic acid, antimony trioxide, white petrolatum, titanium oxide, cadmium oxide, borax, glycerin, dibutyltin dimalate, and the like. Among these,
Zinc white, tribasic lead sulfate, vulcanization accelerators and the like are preferred.

The amount of these foaming aids added is preferably from 5 parts by weight to 200 parts by weight, more preferably from 50 parts by weight to 150 parts by weight, based on the foaming agent. If the amount of the foaming aid added is small, the effect of decomposing the foaming agent will be small and the drop in foaming temperature will be small. On the other hand, if the amount of foaming aid added is large, the fusion layer will foam during the production of an insulated wire.

The blowing agent used in the present invention is one that decomposes when heated to generate nitrogen gas, carbon dioxide gas, carbon monoxide, ammonia gas, etc. Organic blowing agents and inorganic blowing agents can be used. Examples of organic blowing agents include azo dicarbonamide (A.D.C.A.) and azobisisobutyronitrile (A.I.B.N.) for azo systems, and dinitrosopentamethylenetetramine (for nitroso systems). D.P.T.
), N,N'dinitroso-N,N'-dimethylterephthalamide (D.N.D.M.T.A), and in the hydrazide series, P-toluenesulfonylhydrazide (T.S.H)
, P,P-oxybisbenzenesulfonyl hydrazide (
O. B. S. H), benzenesulfonyl hydrazide (B
．． S. H), and trihydrazinotriazine (T.
H. T), acetone-P-sulfonylhydrazone, etc., and those having different decomposition temperatures and amounts of gas generated are commercially available. These can be used alone or in combination of two or more types dissolved or dispersed in the adhesive coating.

On the other hand, examples of inorganic blowing agents include sodium bicarbonate, ammonium carbonate, ammonium bicarbonate, sodium borohydride, sodium boron hydride, and silicon oxyhydride. Organic blowing agents are preferred because their speed is slower than that of organic blowing agents and gas generation is difficult to control.

[0014] The amount of foaming agent added is 0.1 to the fusion resin.
PHR ~ 50PHR is preferable, more preferably 1PH
R~25PHR. If the amount of foaming agent added is small, no foaming will be observed, and if the amount of foaming agent added is large, the mechanical strength of the adhesive layer will be insufficient.

[0015] As the fusion resin used in the present invention, any resin can be used as long as it exhibits fluidity at high temperatures. For example, butyral resins, phenoxy resins, polyamide resins and other thermoplastic resins can be used. Examples of phenoxy resins include those containing bisphenol A, bisphenol S, and bisphenol F as main components, and modified phenoxy resins. Examples of polyamide resins include various copolyamide resins, 6-nylon resins, 6,6-nylon resins, and 6,10-nylon resins, and examples of thermoplastic resins include copolymerized polyester resins, polybutylene terephthalate resins, and polyethylene terephthalate resins. , thermoplastic polyurethane resin, polycarbonate resin, polyphenylene oxide resin, polyphenylene sulfide resin, polysulfone resin, polyetherimide resin, polyetheretherketone resin, polyetherketone resin, polyethersulfone resin, thermoplastic polyamideimide resin, thermoplastic polyimide Resin etc. can be used. Further, by adding melamine resin, phenol resin, isocyanate, etc. to the above resin, it is possible to crosslink it and make it partially thermosetting type. Among these resins mentioned above, butyral resin, phenoxy resin, and copolymerized polyamide resin are preferred because they have a good balance of fusing strength and fusing temperature and are currently used for the fusing layer. Furthermore, in the present invention, the use of butyral resin and phenoxy resin, which have slightly poor fluidity, is more preferable because the adhesive layer is foamed to fill the voids between the wires, as they have a large effect of improving fluidity.

[0016] The fusing paint used in the present invention uses the fusing resin as cyclohexanone, xylene, NM2P, DMAC,
It is obtained by dissolving or dispersing a predetermined amount of a foaming agent or foaming aid in a solvent such as SMF or cresol to a concentration of about 10% to 50%. In addition, when dispersing, a more uniform paint can be obtained by dispersing with a dissolver, ball mill, sand mill, etc.

The insulating film used in the present invention is not limited in any way, and any commonly used insulating film can be used. For example, polyvinyl formal resin,
The main components are thermosetting polyurethane resin, thermosetting acrylic resin, epoxy resin, thermosetting polyester resin, thermosetting polyesterimide resin, thermosetting polyesteramideimide resin, aromatic polyamide resin, thermosetting polyamideimide resin, and thermosetting polyimide resin. You can use whatever you want.

The self-bonding insulated wire of the present invention can be obtained by applying and baking the above-mentioned fusing paint onto these insulating coatings under baking conditions that do not decompose the foaming agent.

The obtained self-fusing insulated wire is wound into a predetermined coil shape, and the fusing layer is foamed by heating with electricity or drying with hot air. At that time, foaming occurs even when the heating temperature is as low as around 150°C.

[0020]

EXAMPLES The present invention will be explained in detail based on the following examples.

[Comparative Example 1] Phenoxy resin (YP-50
: Toto Kasei) was dissolved in NM2P to a concentration of 25%, and further A. D. C. 10 PHR of A-vinihole AC3M (Eiwa Kasei Kogyo) was added and mixed and stirred with a dissolver to obtain a fusion coating. A polyester imide varnish (Isomid 40: Nippon Schenectady) was coated and baked on a 3.0 mmφ copper wire using a well-known method in a horizontal furnace with a furnace length of 3 m to a film thickness of 2.
A 1 micron type 1 esterimide wire was created. Further, the above-mentioned fusing paint was applied and baked at an oven temperature of 250° C. to form a fusing layer of 8 microns, thereby producing a self-fusing insulated wire. A helical coil was made from the obtained self-bonding insulated wire and left in a constant temperature bath at a predetermined temperature for 5 minutes, and the temperature at which foaming occurred was examined. Table 1 shows the results and the appearance of the self-bonding insulated wire when it was made.

[Example 1] The same procedure as in Comparative Example 1 was carried out except that zinc white was added as a foaming aid to the fusion coating of Comparative Example 1 in an amount of 2 PHR relative to the foaming agent.

[Example 2] The same procedure as in Comparative Example 1 was carried out except that 5 PHR of zinc white was added as a foaming aid to the fusing paint of Comparative Example 1 based on the foaming agent.

[Example 3] The same procedure as in Comparative Example 1 was carried out except that 50 PHR of zinc white was added as a foaming aid to the fusion coating of Comparative Example 1 based on the foaming agent.

[Example 4] The same procedure as in Comparative Example 1 was carried out except that 100 PHR of zinc white was added as a foaming aid to the fusing paint of Comparative Example 1 based on the foaming agent.

[Example 5] The same procedure as in Comparative Example 1 was carried out except that 200 PHR of zinc white was added as a foaming aid to the fusion coating of Comparative Example 1 based on the foaming agent.

[Example 6] The same procedure as in Comparative Example 1 was carried out except that 50 PHR of BZ was added as a foaming aid to the fusion coating of Comparative Example 1 based on the foaming agent.

[Example 7] The same procedure as in Comparative Example 1 was carried out except that 100 PHR of TLB was added as a foaming aid to the fusion coating of Comparative Example 1 based on the foaming agent.

[Example 8] The same procedure as in Comparative Example 1 was carried out except that 300 PHR of zinc white was added to the foaming agent as a foaming aid to the adhesive coating of Comparative Example 1.

[0030]

[Table 1]

[0031]

As described above, the use of the self-bonding insulated wire of the present invention has the advantage that the fusion layer can be foamed at a low temperature of around 150°C.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a self-bonding insulated wire of the present invention.

[Explanation of symbols]

1 Conductor 2 Insulating film 3 Self-adhesive layer

Claims (3)

[Claims] 1. A self-bonding insulated wire characterized in that a welding layer containing a foaming agent and a foaming aid is formed on a metal conductor via an insulating layer. 2. The self-fusing insulated wire according to claim 1, wherein the amount of the foaming aid added is from 5 parts by weight to 200 parts by weight based on the foaming agent. 3. A coil characterized in that the self-fusing insulated wire according to claim 1 is wound, and then the fusing layer is foamed.