JP5578439B2 - Insulated wire - Google Patents

Description

  The present invention relates to an insulated wire, and in particular, an insulating film composed of an aromatic polyamide resin insulating paint obtained by synthesizing aromatic diisocyanate and aromatic dicarboxylic acid as main components of an isocyanate component and an acid component, respectively, in a basic solvent. It is related with the insulated wire which has.

  Polymers containing ester groups or amide groups have higher adhesion to metal surfaces than polymers that do not contain them, so resins such as polyester resins, polyesterimide resins, and polyamideimide resins are used in various fields. Has been.

  In particular, in the field of enameled wire used as a material for forming coils of electric equipment such as motors and generators, adhesion between conductors and insulating films, or flexibility, wear resistance, heat resistance, etc. In order to obtain these characteristics, it is common practice to produce an insulated wire (enameled wire) in which an insulating coating is formed by applying and baking an insulating coating made of polyesterimide resin or polyamideimide resin on a conductor. Yes. In recent years, in the field of enameled wires, there has been a demand for insulated wires having higher adhesion and wear resistance than conventional insulated wires having an insulation film made of polyesterimide resin insulation paint, polyamideimide resin insulation paint, or the like. .

  On the other hand, in fields other than enameled wires, aromatic polyamide resins synthesized by polycondensation of aromatic diamine and aromatic dicarboxylic acid chloride in solution are also used industrially (for example, Patent Document 1). ).

  However, the aromatic polyamide resin has a small number of industrially usable aromatic carboxylic acid chlorides, and the aromatic polyamide resin that can be synthesized is limited, or an aromatic diamine and an aromatic carboxylic acid dichloride are polymerized. At this time, there is a concern that halides such as hydrogen chloride are generated. As a method for suppressing the generation of halides such as hydrogen chloride, the addition of a neutralizing agent or the like has been proposed (for example, Patent Document 2). Although the halide is removed from the molecule of the aromatic polyamide resin by this neutralizing agent, a trace amount of chlorine ions and the like always remain in the solution in which the aromatic polyamide resin is dissolved. Therefore, in the field of enameled wire where an insulating coating is applied on a conductor and baked to form an insulating coating, when the aromatic polyamide resin produced by the above method is used for the insulating coating, There is a concern that the halide in the solution volatilizes in the baking furnace, causing erosion of the furnace wall, exhaust gas, and the like.

  Further, methods for directly synthesizing an aromatic polyamide from an aromatic diamine and an aromatic dicarboxylic acid are disclosed in, for example, Patent Document 3 and Patent Document 4. However, the aromatic polyamide synthesized by these methods has a long aliphatic group in the molecular main chain, and it can be said that the heat resistance, rigidity, hydrolysis resistance, etc. for application to enameled wire are sufficient. There wasn't. Furthermore, complicated operations such as decompression may be performed, which is a method that is difficult to industrialize. Further, since this method cannot be synthesized in a solution, it has been practically impossible to apply to the field of enameled wire in which an insulating coating is applied and baked to form an insulating film.

On the other hand, a method for directly synthesizing an aromatic polyamide from an aromatic diisocyanate and an aromatic dicarboxylic acid is not used in an insulating coating for enameled wire, but is disclosed in Patent Documents 5 and 6. Aromatic polyamides obtained by these methods impart melt fluidity so that injection molding can be performed. Therefore, 0.5 to 0.75 mol of aromatic diisocyanate and aliphatic diisocyanate are added to 1 mol of aromatic dicarboxylic acid. The range is 0.5 to 0.25 mol, or 0.65 to 0.85 mol of aromatic dicarboxylic acid and 0.35 to 0.15 of aliphatic dicarboxylic acid per mol of aromatic diisocyanate. It is supposed to be in the molar range. In Patent Documents 5 and 6, aromatic polyamides synthesized from terephthalic acid and tolylene-2,4-diisocyanate are described as comparative examples. However, it was not at all recognized whether poly A phagemid resin having such a structure can be applied as an insulating paint for enamel wire.

JP 2004-91735 A JP 2004-137407 A JP 11-228690 A JP 2000-95835 A JP-A-6-136117 JP-A-6-107786

  The object of the present invention is to solve the problems in the prior art as described above, and has heat resistance and wear resistance equal to or higher than those of the prior art, and more closely adherence to the conductor than before. Is to provide a high insulated wire.

In order to achieve the above object, the present invention has the following configuration.
[1] An aromatic polyamide comprising a conductor, an isocyanate component containing an aromatic diisocyanate as a main component on the conductor, and an acid component containing an aromatic dicarboxylic acid containing no halogen element in the molecular chain as a main component And an insulating film formed by applying and baking a resin insulating paint.
[2] The proportion of the aromatic diisocyanate in the isocyanate component is 60 to 100 mol%, and the proportion of the aromatic dicarboxylic acid in the acid component is 70 to 100 mol%. The insulated wire according to 1.
[3] The insulated wire according to claim 1, wherein an isocyanate group which is a terminal group of the aromatic polyamide resin insulating paint is sealed with a urethane bond.
[4] The insulated wire according to claim 1, wherein the aromatic diisocyanate is mainly composed of tolylene diisocyanate or diphenylmethane diisocyanate.
[5] The insulated wire according to claim 4, wherein the aromatic diisocyanate is mainly composed of tolylene diisocyanate or 2,4′-diphenylmethane diisocyanate.
[6] The insulated wire according to [1], wherein the aromatic polycarboxylic acid is mainly composed of either isophthalic acid or terephthalic acid.
[7] The insulated wire according to [3], wherein the sealing agent for sealing the isocyanate group comprises any one of alcohols, phenols and oximes.

  According to the present invention, a high molecular weight aromatic polyamide resin insulating paint that is substantially free of halides and is easily obtained without complicated operations is applied and baked on a conductor. By forming an insulating film, it is possible to provide an insulated wire that has heat resistance and wear resistance equal to or higher than those of conventional ones, has higher adhesion to conductors than conventional ones, and has excellent flexibility. .

It is sectional drawing which shows one Example of the insulated wire which concerns on this invention. It is sectional drawing which shows the other Example of the insulated wire which concerns on this invention.

Embodiments of the present invention will be described below.
<Insulated wire>
FIG. 1 shows an example of the structure of an insulated wire according to the present invention. This insulated wire is obtained by forming an aromatic polyamide resin insulating film 2 on a conductor, and is obtained by applying and baking an aromatic polyamide resin insulating paint described in the following embodiment around the conductor 1. .

  Moreover, the other structural example of the insulated wire which concerns on FIG. 2 at this invention is shown. In this insulated wire, an aromatic polyamide resin insulation film 2 is formed on the surface of the conductor 1, and a polyimide resin insulation paint, a polyester resin insulation paint, a polyesterimide resin insulation paint, and a H-class polyester are formed on the aromatic polyamide resin insulation film 2. Insulating film 3 made of imide resin insulating paint, polyamideimide resin insulating paint or the like is formed. Here, the insulating film 3 may be a partial discharge resistant insulating film made of a partial discharge resistant insulating paint having a high partial discharge start voltage.

  In the insulated wire shown in FIGS. 1 and 2, the conductor 1 has a circular cross-sectional shape. However, the present invention is not limited to this, and the conductor 1 has a rectangular cross section. May be. Moreover, as a material of the conductor 1, copper, aluminum, etc. can be used, Furthermore, low oxygen copper, an oxygen free copper, etc. may be sufficient. Further, in the insulated wire shown in FIGS. 1 and 2, a resin coating made by adding a lubricant such as carnauba wax to the base resin is applied to the outer periphery of the polyamideimide resin insulating film to form an insulating film with high lubricity. May be.

<Aromatic polyamide resin insulation paint>
In the insulated wire of the present invention, the aromatic polyamide resin insulating paint used for forming the insulating film is a wholly aromatic polyamide synthesized from components in which the isocyanate and acid components are all composed of aromatic diisocyanate and aromatic dicarboxylic acid. not only, including a poly a bromide synthesized from an isocyanate component and an acid component comprising an aromatic diisocyanate and an aromatic dicarboxylic acid of the as a main component, respectively.

  Aromatic polyamide resin insulating paint is an isocyanate component and an acid component constituting an aromatic polyamide resin in a basic reaction solvent mainly composed of N, N-dimethylformamide, N-methyl-2-pyrrolidone (NMP), etc. Is obtained by decarboxylation and condensation reaction in a substantially equimolar amount under a nitrogen gas stream. Such an aromatic polyamide resin insulating coating is formed with molecular structure units arranged between amide bonds relatively regularly and has a slight crystallinity due to hydrogen bonds, π-π interaction, and the like.

  The above-mentioned aromatic polyamide resin insulating coating can be applied as it is on a conductor and baked to form an insulating film, but mainly by reacting an isocyanate group, which is a terminal group of the polyamide resin, with an OH group-containing compound. Forming a urethane bond and sealing (masking) is desirable because the pot life of the paint can be improved. In addition, the polyamide resin insulating paint has a resin content concentration (non-volatile content) of 30% by mass or more from the viewpoint of improvement in manufacturing efficiency and reduction in manufacturing cost when forming an insulating film on the conductor, and from the viewpoint of coating viscosity. It is desirable that it be 90 mass% or less.

<Isocyanate component>
As an isocyanate component constituting the aromatic polyamide resin of the present invention, an aromatic diisocyanate is used as a main component in order to realize heat resistance of 200 ° C. or higher and high mechanical strength. Here, the main component means a component having a structural unit of 50 mol% or more based on all components of the isocyanate. Examples of the aromatic isocyanate include phenylene-1,3-diisocyanate, phenylene-1,4-diisocyanate, tolylene-2,6-diisocyanate, tolylene-2,4-diisocyanate, 1-methoxybenzene-2,4-diisocyanate, 1- Methoxybenzene-2,4-diisocyanate, 1-chlorophenylene diisocyanate, tetrachlorophenylene diisocyanate, diphenylmethane-4,4′-diisocyanate, diphenylmethane-2,4′-diisocyanate, diphenylsulfide-4,4-diisocyanate, diphenylsulfone- 4,4'-diisocyanate, diphenyl ether-4,4'-diisocyanate, diphenyl ether-3,4'-diisocyanate, diphenyl ketone-4,4'-dii Socyanate, naphthalene-2,6-diisocyanate, naphthalene-1,4-diisocyanate, naphthalene-1,5-diisocyanate, 2,4′-biphenyl diisocyanate, 4,4′-biphenyl diisocyanate, 3,3′-methoxy-4 , 4′-biphenyl diisocyanate, anthraquinone-2,6-diisocyanate, triphenylmethane-4,4′-diisocyanate, azobenzene-4,4′-diisocyanate, etc. Diphenylmethane diisocyanate or tolylene diisocyanate is preferable in terms of improving the solubility of the solvent in the solvent. In the present invention, in particular, diphenylmethane-4,4′-diisocyanate, diphenylmethane-2,4′-diisocyanate, tolylene-2,6-diisocyanate, tolylene-2,4-diisocyanate, or tolylene-2,6-diisocyanate and tolylene-2, More preferred is m-tolylene-diisocyanate, which is a mixture with 4-diisocyanate.

  In addition to the above-mentioned aromatic isocyanate, the present invention includes aliphatic diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexyl diisocyanate, meta or para xylylene diisocyanate, and hydrogenated xylylene diisocyanate, alicyclic diisocyanates, or side chains. It is possible to add any of diisocyanate components selected from aromatic diisocyanates having a substituent. Moreover, multimers, such as polyfunctional isocyanates, such as a triphenylmethane triisocyanate, and a polymeritic isocyanate, may be sufficient. These isocyanates are added in a proportion of less than 50 mol%, more preferably less than 40 mol%, based on all components of the isocyanate. These isocyanates may be added for the purpose of imparting flexibility of the polyamide resin, improving solubility in a solvent, or further increasing the heat resistance, but if the blending ratio is 50 mol% or more, polyimide Decrease in heat resistance and hydrolyzability of the resin may become significant, and the resin may become extremely brittle, and cannot be used as an insulating paint for heat resistant wires. In particular, in order to obtain an insulated wire with higher heat resistance and wear resistance, the blending ratio of isocyanate components other than aromatic diisocyanate should be further less than 40 mol%, that is, the blending ratio of aromatic diisocyanate is 60 moles. % Or more is more desirable.

<Acid component>
Examples of the acid component constituting the aromatic polyamide resin of the present invention include isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, and 2,5-naphthalene. Aromatic dicarboxylic acids such as dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid can be used as the main component. These aromatic dicarboxylic acids are suitable not only for improving the heat resistance but also for improving the solubility of the polyamide resin in the solvent. Among these aromatic dicarboxylic acids, isophthalic acid and terephthalic acid are particularly preferable in terms of adhesion.

  In the present invention, in addition to the above aromatic dicarboxylic acids, trimellitic acid (TMA), tribasic acids of trimellitic acid derivatives, tricarboxylic acids such as tris (2-carboxyethyl) isocyanurate (CIC), and trimethic acid Aliphatic dicarboxylic acids (adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid) and the like can be partially added in combination with the above-mentioned aromatic dicarboxylic acid. In the acid component constituting the aromatic polyamide resin of the present invention, the blending ratio of the aromatic dicarboxylic acid is at least 50 mol% or more, preferably 70 mol% from the viewpoint of heat resistance, mechanical strength and hydrolyzability. That's it. If the blending ratio of the above aromatic dicarboxylic acid is less than 50 mol%, the heat resistance of the polyamide resin may deteriorate and the hydrolyzability may become remarkable or the resin may become extremely brittle. I can't do it. In particular, in order to obtain an insulated wire having higher heat resistance and wear resistance, the blending ratio of the aromatic dicarboxylic acid is set to 70 mol% or more, that is, the carboxylic component other than the aromatic dicarboxylic acid. More desirably, the blending ratio is less than 30 mol%.

  In the present invention, a compound having the structure shown above is used as an isocyanate component and an acid component. In order to improve the solubility of the synthesized polyimide resin in a solvent, an aromatic diisocyanate is used as a component of the polyamide resin. Alternatively, it is preferable to use a component for forming a bent structure of the resin in at least one of the aromatic dicarboxylic acids. Therefore, it is preferable to use diphenylmethane-2,4'-diisocyanate, tolylene-2,6-diisocyanate, tolylene-2,4-diisocyanate as the aromatic diisocyanate component, and isophthalic acid as the aromatic dicarboxylic acid. These components can be used in combination with diphenylmethane-4,4'-diisocyanate or terephthalic acid, which is a component that forms a linear resin structure, depending on the heat resistance of the polyimide resin.

<Sealant>
It is effective to use any compound of alcohols, phenols, and oximes as a sealing material that is contained in polyamide resin insulation paint and seals the isocyanate group that is the terminal group of the polyamide resin with a urethane bond. is there. Examples of alcohols used in the present embodiment include methanol, ethanol, propanol, and benzyl alcohol. Examples of phenols include phenol, cresol, xylenol, and the like. Examples of oximes include methyl ethyl ketoxime, cyclohexyl oxime, and benzophenone oxime. These can be used alone or in a mixture of two or more to suppress the thickening of the paint, so that the paint has excellent pot life and is easy to use. Other sealing agents, such as monovalent carboxylic acids such as benzoic acid, have a small effect of suppressing the thickening of the paint in the aromatic polyamide resin synthesized in the present invention.

  In addition, depending on the synthesis conditions of the aromatic polyamide, the viscosity increase rate of the paint may be slowed down and the pot life may be stable. In that case, the above-described sealing agent may not be used.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

[Insulated wire manufacturing method]
The insulated wire of the following Example and the comparative example was manufactured as follows.

  First, in a flask equipped with a stirrer, a reflux condenser, a nitrogen inlet pipe, and a thermometer, the molar ratio of the isocyanate component and the acid component shown in the following Examples and Comparative Examples is 1.02: 1.0 or 1.0: Each amount was adjusted to 1.0, and 490 g of N-methyl-2-pyrrolidone (NMP) was added as a solvent, and the mixture was heated to 140 ° C. in about 1 hour with stirring in a nitrogen atmosphere. After performing synthesis by reacting at this temperature for a predetermined time in a range of 2 to 5 hours so that a polyamide resin solution having an average molecular weight of about 22000 is obtained, a predetermined amount of the sealant shown in the following Examples and Comparative Examples Was mixed with an aromatic polyamide solution and mixed to seal the end group of the isocyanate component to stop the synthesis reaction. After cooling, it was diluted with 210 g of NMP to obtain an aromatic polyamide resin insulating paint having a resin concentration (nonvolatile content) of about 30 to 32% by weight.

  The thus obtained aromatic polyamide resin insulation coating is applied and baked on a 0.80 mm copper conductor to form an aromatic polyamide resin insulation film having a film thickness of 30 μm, and the insulation having the structure shown in FIG. I got an electric wire. About the obtained insulated wire, the following method evaluated the adhesiveness, flexibility, abrasion resistance, and softening resistance. About each evaluation result, in order to judge pass or failure, the target value was set with reference to the actual value of the insulated wire put into practical use.

[Evaluation method]
(1) Adhesiveness The adhesiveness test (peel) was measured according to "JISC 3003" 8.1b "twist method". At this time, the number of rotations when the insulating film floats from the conductor (number of times: 360 ° is one time) is 130 times or more is accepted (O), and the number of rotations is less than 130 times is rejected ( X).

  In addition, the adhesion test (peel after deterioration) is measured in accordance with the “JISC 3003“ 8.1b ”twist method” after leaving the obtained insulated wire in a thermostatic bath at 160 ° C. for 24 hours. It was. At this time, when the insulating film floated from the conductor, the number of rotations was 85 times or more was evaluated as acceptable (◯), and the number of rotations less than 85 was evaluated as unacceptable (x).

(2) Flexibility In the flexibility test (non-extension), an insulated wire that is not stretched is wound around a winding rod having a diameter 1 to 10 times the conductor diameter of the insulated wire according to “JISC 3003” 7.1. Winding was performed by a method in accordance with 1a “winding”, and the minimum winding double diameter (d) at which no crack was observed in the insulating film was measured using an optical microscope. At this time, the minimum winding double diameter (d) in which no crack was observed in the insulating film was 1d or less, and the pass (o) was 2d or more.

  In addition, the flexibility test (30% elongation) is performed by 30% elongation according to the method in accordance with “JISC 3003“ 7.1.1a ”winding”, and then the flexibility test (no elongation) is performed in an equivalent manner. It was measured. At this time, the minimum winding double diameter (d) in which no crack was observed in the insulating film was 2d or less, and the case where it was 3d or more was rejected (x).

(3) Abrasion resistance The wear resistance test was based on JISC 3003, and the number of times until the film was abraded and the conductor was exposed when reciprocating friction was applied was measured. At this time, a case where the number of times until the conductor was exposed was 200 times or more was evaluated as a pass (◯), and a case where the number was less than 200 times was evaluated as a reject (x).

(4) Softening resistance The softening resistance was measured in accordance with “JISC 3003“ 11.2 ”Method B” by measuring the temperature when short-circuited (short-circuit temperature). At this time, the thing whose short circuit temperature is 350 degreeC or more was evaluated as the pass ((circle)), and the thing below 350 degreeC was evaluated as the disqualification (x).

[Example 1]
Tolylene diisocyanate as an isocyanate component (TDI: mixture of tolylene-2,4-diisocyanate and tolylene-2,6-diisocyanate) 162.4 g (0.9322 mol), isophthalic acid as an acid component 151.8 g (0.9135 mol) , and using the benzyl alcohol 10g as a sealing agent, to obtain an aromatic poly a phagemid resin insulating coating material.

[Example 2]
Tolylene diisocyanate (TDI: a mixture of tolylene-2,4-diisocyanate and tolylene-2,6-diisocyanate) 121.8 g (0.6992 mol) and hexamethylene-1,6-diisocyanate (HDI) 39.2 g as isocyanate components (0.2330 mol), 129.0 g (0.7765 mol) of isophthalic acid and 20.0 g (0.1370 mol) of adipic acid as an acid component, and 10 g of benzyl alcohol as a sealant, an aromatic polyamide resin An insulating paint was obtained.

[Example 3]
Tolylene diisocyanate (TDI: mixture of tolylene-2,4-diisocyanate and tolylene-2,6-diisocyanate) 97.4 g (0.5593 mol) and hexamethylene-1,6-diisocyanate (HDI) 62.7 g as isocyanate components (0.3729 mol), 74.3 g (0.6395 mol) of isophthalic acid as an acid component, 40.0 g (0.2741 mol) of adipic acid, and 10 g of benzyl alcohol as a sealant, an aromatic polyamide resin An insulating paint was obtained.

[Example 4]
As the isocyanate component, 188.7 g (0.7540 mol) of 4,4′-diphenylmethane diisocyanate (4,4′-MDI), 122.8 g (0.7390 mol) of isophthalic acid as the acid component, and benzyl alcohol as the sealant An aromatic polyamide resin insulating paint was obtained using 10 g.

[Example 5]
As isocyanate components, 151.0 g (0.6032 mol) of 4,4′-diphenylmethane diisocyanate (4,4′-MDI), 25.4 g (0.1508 mol) of hexamethylene-1,6-diisocyanate (HDI), acid An aromatic polyamide resin insulating coating was obtained using 122.8 g (0.7390 mol) of isophthalic acid as a component and 10 g of benzyl alcohol as a sealant.

[Example 6]
188.7 g (0.7540 mol) of 2,4′-diphenylmethane diisocyanate (2,4′-MDI) as the isocyanate component, 122.8 g (0.7390 mol) of terephthalic acid as the acid component, and benzyl alcohol as the sealant An aromatic polyamide resin insulating paint was obtained using 10 g.

[Example 7]
188.7 g (0.7540 mol) of 2,4′-diphenylmethane diisocyanate (2,4′-MDI) as the isocyanate component, 110.5 g (0.6651 mol) of terephthalic acid and 13.9 g of azelaic acid (0 0.039 mol) and 10 g of benzyl alcohol as a sealant, an aromatic polyamide resin insulating paint was obtained.

[Example 8]
Tolylene diisocyanate as the isocyanate component (TDI: mixture of tolylene-2,4-diisocyanate and tolylene-2,6-diisocyanate) 162.4 g (0.9322 mol), terephthalic acid as the acid component 151.8 g (0.9135 mol) An aromatic polyamide resin insulating paint was obtained using 10 g of benzyl alcohol as a sealant.

[Example 9]
As the isocyanate component, 146.1 g (0.8390 mol) of tolylene diisocyanate (TDI: mixture of tolylene-2,4-diisocyanate and tolylene-2,6-diisocyanate) and 17.5 g of m-xylylene diisocyanate (XDI) (0. 0932 mol), 139.3 g (0.8384 mol) of terephthalic acid and 13.6 g (0,932 mol) of adipic acid as the acid component, and 10 g of benzyl alcohol as the sealant, an aromatic polyamide resin insulating paint is obtained. It was.

[Example 10]
As the isocyanate component, tolylene diisocyanate (TDI: a mixture of tolylene-2,4-diisocyanate and tolylene-2,6-diisocyanate) 89.3 g (0.5127 mol) and m-xylylene diisocyanate (XDI) 79.0 g (0.0. 4195 mol), 139.3 g (0.8384 mol) of terephthalic acid and 13.6 g (0,932 mol) of adipic acid as the acid component, and 10 g of benzyl alcohol as the sealant, an aromatic polyamide resin insulating paint is obtained. It was.

[Example 11]
Tolylene diisocyanate (TDI: mixture of tolylene-2,4-diisocyanate and tolylene-2,6-diisocyanate) as the isocyanate component 162.4 g (0.9322 mol), isophthalic acid 154, 9 g (0.9322 mol) as the acid component with, resulting after the synthesis in the same manner as in example 1, was diluted with NMP was allowed to cool, resin concentration (nonvolatile content) of about 31% by weight of aromatic poly a phagemid resin insulating coating material It was. In this example, the ratio of the isocyanate component to the acid component was 1.0: 1.0, and the end groups of the isocyanate component were not sealed with a sealant.

[Example 12]
Tolylene diisocyanate as the isocyanate component (TDI: mixture of tolylene-2,4-diisocyanate and tolylene-2,6-diisocyanate) 162.4 g (0.9322 mol), isophthalic acid 151, 8 g (0.9135 mol) as the acid component , and with phenol 8.7g as a sealing agent, to obtain an aromatic poly a phagemid resin insulating coating material.

[Example 13]
Tolylene diisocyanate as the isocyanate component (TDI: mixture of tolylene-2,4-diisocyanate and tolylene-2,6-diisocyanate) 162.4 g (0.9322 mol), isophthalic acid 151, 8 g (0.9135 mol) as the acid component , and using methyl ethyl ketoxime (ME ketoxime) 8.1 g as a sealing agent, to obtain an aromatic poly a phagemid resin insulating coating material.

[Comparative Example 1]
A commercially available highly adhesive polyamideimide resin insulating paint (AJ4-26 manufactured by Hitachi Chemical Co., Ltd.) was used.

[Comparative Example 2]
As the isocyanate component, 73.1 g (0.4195 mol) of tolylene diisocyanate (TDI: mixture of tolylene-2,4-diisocyanate and tolylene-2,6-diisocyanate) and 86.2 g of hexamethylene-1,6-diisocyanate (0. 5127 mol), 136.6 g (0.8222 mol) of isophthalic acid and 13.3 g (0.0913 mol) of adipic acid as an acid component, and 10 g of benzyl alcohol as a sealant, an aromatic polyamide resin insulating paint Obtained.

[Comparative Example 3]
As the isocyanate component, 73.1 g (0.4195 mol) of tolylene diisocyanate (TDI: mixture of tolylene-1,4-diisocyanate and tolylene-2,6-diisocyanate) and 96.5 g of m-xylylene diisocyanate (XDI) ( 0.5127 mol), 68.3 g (0.4111 mol) of terephthalic acid and 73.4 g (0, 5024 mol) of adipic acid as acid components, and 10 g of benzyl alcohol as a sealant, an aromatic polyamide resin insulating paint Got.

  Tables 1 and 2 show the compositions of the aromatic polyamide resin insulating paints of Examples 1 to 13, Comparative Examples 2 and 3, and the highly adhesive polyamideimide resin insulating paint of Comparative Example 1. Further, in Tables 3 and 4, an insulated wire in which an insulator film was formed using the polyamide resin insulating paints of Examples 1 to 13, Comparative Examples 2 and 3, and the highly adhesive polyamideimide resin insulating paint of Comparative Example 1 ( Enamel wire properties (adhesion, flexibility, wear resistance, softening resistance). Tables 3 and 4 also show the target values for each evaluation item.

  As shown in Table 3 and Table 4, the enameled wire formed by applying and baking the aromatic polyamide resin insulating paint shown in Examples 1 to 13 has good adhesion and flexibility, and wear resistance and resistance. It turns out that it is excellent in softening property.

In Examples 1 to 13, when an aromatic polyamide is synthesized, an isocyanate or an acid having a bent structure such as TDI, 2,4′-MDI, or isophthalic acid is used. improved, good aromatic polyamylene de resin insulating coating appearance without white turbidity by precipitates can be obtained. As a result, the enameled wire formed by applying and baking an aromatic polyamide resin insulating paint on the conductor has good properties such as adhesion and flexibility, and in addition, 4,4'-MDI, terephthalic acid, etc. By using together an isocyanate or an acid having a linear structure, an insulated wire having an aromatic polyamide resin insulating film with improved wear resistance and softening resistance can be obtained.

  If the molecular chain in the resin is only a linear structure, the crystallinity of the resin becomes too high, so that the solubility in a solvent is reduced, and the resin tends to precipitate and the paint tends to become cloudy. In that case, it is possible to obtain an insulated wire exhibiting the effects of the present invention by using a paint having a low resin content concentration (non-volatile content).

  In the present invention, it was found that if the molar ratio of the aromatic diisocyanate and the aromatic dicarboxylic acid to the isocyanate component and the acid component is 50 mol% or more, respectively, an insulated wire exhibiting the effects of the present invention can be obtained. Furthermore, although specific measured values are not shown in Tables 3 and 4, the characteristics can be further improved by setting the respective molar ratios to 60 to 100 mol% and 70 to 100 mol%. I understood. In Example 10, the evaluation results in adhesion, wear resistance, and softening resistance were slightly inferior to those of the other examples, only slightly exceeding the target values. Therefore, in the present invention, it is more preferable that the ratio of the aromatic diisocyanate in the isocyanate component is in the range of 60 to 100 mol%, and the ratio of the aromatic dicarboxylic acid in the acid component is in the range of 70 to 100 mol%. .

  The polyamide resin compositions of Examples 1 to 10 and 12 to 13 show little increase in the viscosity of the paint after standing for 1 week at room temperature, and the isocyanate groups which are the end groups of the polyamide resin are sealed with a sealing agent. The pot life was stable as compared with the polyamide resin composition of Example 11 which is not. Moreover, although Examples 12-13 differed from Example 1 in the kind of sealing material, the big difference was not looked at by the characteristic of the enameled wire.

  On the other hand, Comparative Example 1 is an enameled wire in which an insulating film is formed on a conductor by using a commercially available highly adhesive polyamideimide resin coating, but compared with the aromatic polyamide resin insulating film of Example, the adhesion The flexibility was particularly low, and the drop in the peel value after 24 hours of degradation at 160 ° C. was particularly large.

  In Comparative Examples 2 and 3, since the molar ratio of at least one of the aromatic diisocyanate and the aromatic dicarboxylic acid is less than 50 mol% with respect to the isocyanate component and the acid component, respectively, not only the flexibility, Abrasion resistance and softening resistance were greatly reduced.

  As described above, according to the present invention, when an aromatic polyamide resin is produced from an aromatic diisocyanate and an aromatic dicarboxylic acid through a solution polymerization step in a basic solvent, decomposition of monomers and side reactions are prevented, An industrially useful aromatic polyamide resin insulating coating having a high degree of polymerization and substantially free of halogen ions can be easily obtained. Furthermore, by applying and baking the aromatic polyamide resin insulation paint on the conductor to form an insulating film, it has heat resistance and wear resistance equal to or higher than conventional ones, and more closely adhered to the conductors than before. It is possible to provide an insulated wire having high flexibility and excellent flexibility.

  DESCRIPTION OF SYMBOLS 1 ... Conductor, 2 ... Aromatic polyamide resin insulation film, 3 ... Insulation film.

Claims (7)

Conductors,
On the conductor, an aromatic polyamide resin insulating paint comprising an isocyanate component containing an aromatic diisocyanate as a main component and an acid component containing an aromatic dicarboxylic acid containing no halogen element in the molecular chain as a main component is applied. An insulating film formed by baking;
An insulated wire characterized by comprising:   The proportion of the aromatic diisocyanate in the isocyanate component is 60 to 100 mol%, and the proportion of the aromatic dicarboxylic acid in the acid component is 70 to 100 mol%. Insulated wires.   The insulated wire according to claim 1, wherein an isocyanate group which is a terminal group of the aromatic polyamide resin insulating coating is sealed with a urethane bond.   The insulated wire according to claim 1, wherein the aromatic diisocyanate is mainly composed of tolylene diisocyanate or diphenylmethane diisocyanate.   5. The insulated wire according to claim 4, wherein the aromatic diisocyanate contains either tolylene diisocyanate or 2.4′-diphenylmethane diisocyanate as a main component. The aromatic dicarboxylic acids, insulated wire according to claim 1 consisting mainly of isophthalic acid, any of the terephthalic acid.
  The insulated wire according to claim 3, wherein the sealing agent that seals the isocyanate group is one of alcohols, phenols, and oximes.

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