JPH06103822A - Insulated electric cable - Google Patents

Abstract

PURPOSE:To provide an insulated electric cable having an insulating coating hard to be damaged and high processibility by forming the insulating coating using a polyamideimide-based coating material containing specified polyamideimide. CONSTITUTION:Polyamideimide to be used for insulating coating consists of repeated monomer unit having the formula I, wherein >=70 mole% and <90 mole% of the total R<1> and R<2> of the unit is rigid with straight chain structure and reduced viscosity of the polymer, which shows molecular weight, is 0.4 or more. A polyamideimide-based coating material containing such polyamideimide is applied and baked.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulated wire which is wound around a core of a motor and has excellent workability.

[0002]

2. Description of the Related Art In recent years, with the trend toward smaller size and lighter weight of equipment, there has been a demand for smaller and lighter motors with higher performance. To meet this requirement, it is necessary to wind more insulated wires around the motor core, but this will forcefully pack the insulated wires into the slots of the core, and there is a risk that the insulating coating will be damaged during the winding process. is there. When the insulating coating is damaged, there is a problem that a lare defect, a ground defect, etc. occur, causing a problem in the electric characteristics of the motor.

Therefore, an insulated wire having an insulating coating excellent in mechanical strength, which is formed by coating and baking a polyamideimide-based paint, is usually used for the above-mentioned use. As the polyamide-imide, the following formula (2)
The reaction product of diphenylmethane-4,4'-diisocyanate represented by and trimellitic anhydride is generally used (see, for example, JP-B-44-19274 and JP-B-45-27611). ).

[0004]

[Chemical 2]

[0005]

However, in recent years, motors having smaller size, lighter weight and better performance have been required, and in order to meet the demand, the winding amount of the insulated wire tends to further increase. However, the damage is increasing. Therefore, in order to reduce the damage of the insulating coating as much as possible, it has been studied to add a lubricant such as an organic or inorganic lubricant to the coating to impart lubricity to the surface of the insulating coating. However, damage to the insulating coating cannot be fundamentally resolved.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an insulated electric wire having an insulating coating that is not easily damaged and excellent in work resistance.

[0007]

Means and Actions for Solving the Problems In order to solve the above problems, the present inventors have made extensive studies in order to further improve the hardness of the insulating coating. As a result, the following general formula (1):

[0008]

[Chemical 3]

In the polyamide-imide comprising the repeating unit represented by the formula ( ¹⁾ , a rigid linear structure is introduced into R ¹ and R ² in the formula at a predetermined ratio, and the reduced specific viscosity showing the molecular weight of the polyamide-imide is increased. Then, it was found that the hardness of the insulating coating can be remarkably improved as compared with the conventional one, and an insulated wire excellent in workability can be obtained, and the present invention has been completed.

That is, the insulated wire of the present invention has the above general formula
A repeating unit represented by the formula (1), wherein 70% by mole or more and less than 90% by mole of the total of R ¹ and R ^{2 in} the formula has a rigid linear structure, and the reduced specific viscosity showing the molecular weight is 0. It is characterized by having an insulating coating formed by applying and baking a polyamide-imide-based paint containing a polyamide-imide of 4 or more.

If the proportion of R ¹ and R ^{2 in the} repeating unit represented by the general formula (1) in which R ¹ and R ² are rigid linear structures is less than 70 mol% in total, the elastic modulus of the insulating coating is insufficient. Therefore, the hardness of the insulating coating cannot be sufficiently improved. On the contrary, the ratio of R ¹ and R ² having a rigid linear structure is 90 in total.
When the content is more than mol%, the coating becomes rigid and inferior in flexibility, and when the electric wire is bent, it is easily cracked or peeled off, and the workability of the insulated electric wire deteriorates.

If the reduced specific viscosity indicating the molecular weight is less than 0.4, the molecular weight of polyamideimide is too small.
The hardness of the insulating coating formed by coating and baking cannot be sufficiently improved. The reduced specific viscosity is more preferably 0.5 or more. R in the above general formula (1)
¹ represents a residue of an acid component used as a raw material for polyamideimide in the production methods ¹ to 3 described later, and as a rigid linear structure corresponding to the R ¹ , for example, the following formulas (A1) (A2) The items shown in are listed.

[0013]

[Chemical 4]

Further, R ² in the general formula (1) represents a residue of a diisocyanate component or a diamine component which is reacted with the above acid component, and a rigid linear structure corresponding to the R ² is, for example, the following formula: Examples include (B1) to (B6).

[0015]

[Chemical 5]

The polyamide-imide is obtained by reacting a diamine component and an acid component by copolymerizing an approximately stoichiometric amount of the diisocyanate component and the acid component, and then reacting the reaction product with an approximately equimolar amount of the diisocyanate component. It can be produced by a conventionally known production method such as polymerization or copolymerization of an acid component containing an acid chloride and a diamine component.

In order to increase the strength of the insulating coating by introducing the rigid linear structure as described above into the structure of the polyamide-imide produced by the above-mentioned production method, as the acid component, the above formula (A1) is used. (A2) using a straight-chain acid having a rigid straight chain structure in the molecule, as a diisocyanate component, having a rigid straight chain structure shown in the formula (B1) ~ (B6) in the molecule A linear diisocyanate may be used.

Examples of the linear acid include trimellitic acid, trimellitic anhydride, trimellitic acid chloride, tribasic acid among derivatives of trimellitic acid, biphenyl trimellitic acid, biphenyl trimellitic anhydride. , Biphenyl trimellitic acid chloride, and tribasic acid among biphenyl trimellitic acid derivatives. These may be used alone or in combination of two or more.

Among these, trimellitic acid anhydride is preferably used in terms of availability and cost. Examples of linear aromatic diisocyanates include p-phenylene diisocyanate and 2-fluoro-p-
Phenylene diisocyanate, 2-chloro-p-phenylene diisocyanate, 2-bromo-p-phenylene diisocyanate, 2,3-dichloro-p-phenylene diisocyanate, 2,3,5-trichloro-p-phenylene diisocyanate, 2,3,5 , 6-Tetrachloro-p-phenylene diisocyanate, 2-methyl-p-
Phenylene diisocyanate, 2-ethyl-p-phenylene diisocyanate, 2-butyl-p-phenylene diisocyanate, 2-methoxy-p-phenylene diisocyanate, 2-ethoxy-p-phenylene diisocyanate, 2-butoxy-p-phenylene diisocyanate, biphenyl- 4,4'-diisocyanate, 3,
3'-dichlorobiphenyl-4,4'-diisocyanate, 3,3'-dibromobiphenyl-4,4'-diisocyanate, 3,3'-dimethylbiphenyl-4,4 '
-Diisocyanate, 3,3'-diethylbiphenyl-
4,4'-diisocyanate, 3,3'-dibutylbiphenyl-4,4'-diisocyanate, 3,3'-dimethoxybiphenyl-4,4'-diisocyanate, 3,
3'-diethoxybiphenyl-4,4'-diisocyanate, 3,3'-dibutoxybiphenyl-4,4'-diisocyanate, terphenyl-4,4 "-diisocyanate, naphthylene-1,5-diisocyanate, naphthylene- Examples thereof include compounds such as 2,6-diisocyanate, etc. These may be used alone or in admixture of two or more.

Among these, p-phenylene diisocyanate and 3,3'- are preferable in terms of availability and cost.
Dimethylbiphenyl-4,4'-diisocyanate and naphthylene-1,5-diisocyanate are preferably used. In the production method of, when only the above linear acid or diisocyanate is used as a raw material, R ¹ and R ^{2 of the} repeating unit represented by the general formula (1) have a rigid linear structure. When the ratio becomes 100 mol% in total, the insulating coating becomes rigid and inferior in flexibility as described above, and the tensile strength and the tensile elastic modulus are below the above range,
The insulating coating is easily scratched. Therefore, by using an acid or diisocyanate having a bendable portion or a bendable portion in the molecule together, R ¹ , R ²
The ratio of the rigid linear structure is 70 mol% or more and less than 90 mol% in total, thereby imparting flexibility to the film and balancing the strength and flexibility of the film. There is a need.

Examples of the acid having a bendable portion or a bendable portion in the molecule include tetracarboxylic acid anhydrides and dibasic acids such as pyromellitic dianhydride, biphenyltetracarboxylic acid dianhydride and benzophenone. Tetracarboxylic acid dianhydride, diphenylsulfone tetracarboxylic acid dianhydride, terephthalic acid, isophthalic acid, sulfoterephthalic acid, dicitric acid, 2,5-thiophenedicarboxylic acid, 4,5-phenanthrenecarboxylic acid, benzophenone-4,4 Examples include ′ -dicarboxylic acid, phthaldiimidedicarboxylic acid, biphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, diphenylsulfone-4,4′-dicarboxylic acid and adipic acid. These may be used alone or in combination of two or more.

Among these, isophthalic acid is preferably used in terms of availability and cost. Examples of the diisocyanate having a bendable portion or a bendable portion in the molecule include diphenylmethane-
4,4'-diisocyanate, diphenylmethane-3,
3'-diisocyanate, diphenylmethane-3,4 '
-Diisocyanate, diphenyl ether-4,4'-
Diisocyanate, benzophenone-4,4'-diisocyanate, diphenylsulfone-4,4'-diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, etc. Various conventionally known diisocyanates can be mentioned. These may be used alone or in combination of two or more.

Among these, diphenylmethane-4,4'-diisocyanate is preferably used in terms of availability and cost. According to the above production method, a one-step reaction in which a polyamideimide is synthesized by copolymerizing approximately equimolar amounts of an acid component and a diisocyanate component,
The polyamide-imide type coating material used in the present invention can be manufactured.

Specifically, approximately equimolar amounts of acid component and diisocyanate are used.
The anate component in a suitable organic solvent at 0 to 180 ° C.
When the reaction is performed at a temperature for 1 to 24 hours, the above diisocyanate
Polyamide imide, which is a copolymer of the acid component and the acid component
Is a polyamideimide dissolved or dispersed in an organic solvent
A system paint is obtained. In this case, R in the general formula (1) is
¹, R²The total proportion of rigid linear structures is 70
Acid as a raw material in order to increase the content of the raw material to 90% by mole or more.
Of the total amount of components and diisocyanate components
The total content of chain acids and diisocyanates is 7
Each compound should be 0 mol% or more and less than 90 mol%
The blending ratio may be adjusted.

As the polyamide-imide-based coating used in the present invention, a polyamide-imide-based coating having 90% or more of the total of R ¹ and R ^{2 in} the general formula (1) is a rigid linear structure. Blended with a polyamideimide-based coating having less than 90 mol% of the total of R, R ¹ and R ² having a rigid linear structure, or less than 70 mol% of the total of R ¹ , R ² having a rigid linear structure And a polyamide-imide-based coating that is R ¹ ,
It is also possible to use a mixture of 70 mol% or more of the total amount of R ² with a polyamideimide-based coating having a rigid linear structure. In this case, R ¹ , R
^The ratio of ² having a rigid linear structure is 70 mol% or more, 9
The blending ratio of the polyamideimide-based paint to be blended may be adjusted so that it is less than 0 mol%.

In order to increase the strength of the insulating coating by introducing the rigid linear structure as described above into the structure of the polyamide-imide-based coating material produced by the above-mentioned production method, the acid component of the above-mentioned examples is used as the acid component. A linear acid is used, and the linear diisocyanate exemplified above is used as the diisocyanate component, and the diamine component has a rigid linear structure as shown in each of the above formulas in the molecule. A chain diamine may be used.

Examples of such linear diamines include p-phenylenediamine, 2-fluoro-p-phenylenediamine, 2-chloro-p-phenylenediamine, 2-bromo-p-phenylenediamine and 2,3. -Dichloro-p-phenylenediamine, 2,3,5-trichloro-p-phenylenediamine, 2,3,5,6-tetrachloro-p-phenylenediamine, 2-methyl-p-
Phenylenediamine, 2-ethyl-p-phenylenediamine, 2-butyl-p-phenylenediamine, 2-methoxy-p-phenylenediamine, 2-ethoxy-p-phenylenediamine, 2-butoxy-p-phenylenediamine, biphenyl- 4,4'-diamine, 3,3'-dichlorobiphenyl-4,4'-diamine, 3,3'-dibromobiphenyl-4,4'-diamine, 3,3'-dimethylbiphenyl-4,4'- Diamine, 3,3'-diethylbiphenyl-4,4'-diamine, 3,3'-dibutylbiphenyl-4,4'-diamine, 3,3'-dimethoxybiphenyl-4,4'-diamine, 3,3 ′-
Diethoxybiphenyl-4,4'-diamine, 3,3 '
-Dibutoxybiphenyl-4,4'-diamine, benzidine, 4,4'-diaminobenzanilide, 4,4 "-
Diaminoterphenyl, 1,5-diaminonaphthalene,
2,6-diaminonaphthalene and the like can be mentioned. These may be used alone or in combination of two or more.

Among these, p-phenylenediamine is preferably used in terms of availability and cost.
In the production method of, when only the above linear acid, diisocyanate and diamine are used as raw materials, R ¹ and R ² among the repeating units represented by the general formula (1) are rigid linear structures. Is 10 in total
When the content becomes 0 mol%, the insulating coating becomes rigid and inferior in flexibility as described above, and the tensile strength and the tensile elastic modulus fall below the above range, and the insulating coating becomes easily scratched. Therefore, by using an acid, a diisocyanate or a diamine having a bendable portion or a bendable portion in the molecule in combination, the proportion of R ¹ and R ² having a rigid linear structure is 70 mol% or more in total, When the content is within the range of less than 90 mol%, it is necessary to impart flexibility to the coating film and balance the strength and flexibility of the coating film.

The acid and diisocyanate having a bendable portion or a bendable portion in the molecule include
The various compounds exemplified above may be mentioned. Examples of the diamine having a bendable portion or a bendable portion in the molecule include, for example, m-phenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, diaminodiphenylsulfide, diaminodiphenylpropane, diaminodiphenylether, diaminobenzophenone, diaminodiphenylhexadiene. Fluoropropane,
4,4'-bis (4-aminophenoxy) biphenyl,
4,4 '-[bis (4-aminophenoxy) biphenyl] ether, 4,4'-[bis (4-aminophenoxy) biphenyl] methane, 4,4 '-[bis (4-aminophenoxy) biphenyl] sulfone , 4,4 '-[bis (4-aminophenoxy) biphenyl] propane, etc.,
Various conventionally known diamines can be used. These may be used alone or in combination of two or more.

Among these, diaminodiphenyl ether is preferably used in view of easy availability and cost. In the above-mentioned production method, an approximately stoichiometric amount of a diamine component and an acid component are reacted in an appropriate organic solvent to produce imidodicarboxylic acid, which is copolymerized with an approximately stoichiometric amount of a diisocyanate component. The polyamideimide-based coating material used in the present invention can be produced by the two-step reaction.

Specifically, when the diamine component is reacted with the acid component in an approximately double molar amount in a suitable organic solvent at a temperature of 0 to 150 ° C. for 1 to 24 hours, the reaction between the diamine component and the acid component is carried out. A product, imidodicarboxylic acid, is produced in the reaction solution. Next, a diisocyanate component in an approximately equimolar amount is added to this reaction liquid, and the mixture is added at a temperature of 0 to 150 ° C. to 1
By reacting for -24 hours, a polyamide-imide-based coating material in which polyamide-imide is dissolved or dispersed in an organic solvent is obtained. In this case, the proportion of R ¹ and R ² in the general formula (1) having a rigid linear structure is 70 mol% or more in total, 9
In order to make it less than 0 mol%, it accounts for in the total amount of the acid component, diamine component and diisocyanate component as raw materials,
The compounding ratio of each compound may be adjusted so that the total content ratio of the linear acid, diamine and diisocyanate is 70 mol% or more and less than 90 mol%.

Further, as in the case described above, the general formula (1)
Polyamideimide-based coating material in which 90 mol% or more of the total of R ¹ and R ² has a rigid linear structure, and polyamideimide coating in which less than 90 mol% of the total of R ¹ and R ² has a rigid linear structure Or a polyamideimide-based paint having less than 70 mol% of the total of R ¹ and R ² having a rigid linear structure, and 70 mol% or more of the total of R ¹ and R ² being rigid. It is also possible to use, as a polyamide-imide-based coating material, a mixture with a linear-structured polyamide-imide-based coating material. In this case, R ¹ in the compounding system,
The proportion of R ² having a rigid linear structure is 70 mol% or more,
The blending ratio of the polyamideimide-based paint to be blended may be adjusted so as to be less than 90 mol%.

As the diamine component used in the above production method, the same compounds as those exemplified in the above production method can be used. In order to increase the strength of the insulating coating by introducing a rigid linear structure into the structure of the polyamide-imide-based coating, use linear diamines, and to balance the strength and flexibility of the coating, It is also the same as when a diamine having a bent portion or a bendable portion is used together.

In the production method, the acid chloride copolymerized with the diamine component may be trimellitic acid chloride or its derivative having a rigid linear structure in the molecule as shown in the above formulas. Further, in order to balance the strength and flexibility of the coating film, terephthalic acid chloride or isophthalic acid chloride having a bendable portion or a bendable portion in the molecule is used in combination.

In the above-mentioned production method, the diamine component and the acid component in approximately equimolar amounts are mixed with 0 to 2 in a suitable organic solvent.
When reacted at a temperature of 00 ° C. for 1 to 24 hours, polyamide imide, which is a reaction product of a diamine component and an acid component,
It forms in the reaction solution. Since hydrochloric acid, which is a by-product, is also contained in this reaction liquid, the polyamideimide is filtered,
It is taken out of the reaction solution by a method such as precipitation, or the reaction solution is washed with a large amount of water and then dried. Then, when the polyamideimide after drying is again dissolved in an organic solvent,
A polyamide-imide type coating material is obtained. In this case, in order to make the ratio of R ¹ and R ² in the general formula (1) having a rigid linear structure to 70 mol% or more and less than 90 mol% in total, the acid component as a raw material and the The compounding ratio of each compound may be adjusted so that the total content ratio of the linear acid chloride and the diamine in the total amount of the diamine component is 70 mol% or more and less than 90 mol%.

Further, as in the case described above, the general formula (1)
Polyamideimide-based coating material in which 90 mol% or more of the total of R ¹ and R ² has a rigid linear structure, and polyamideimide coating in which less than 90 mol% of the total of R ¹ and R ² has a rigid linear structure Or a polyamideimide-based paint having less than 70 mol% of the total of R ¹ and R ² having a rigid linear structure, and 70 mol% or more of the total of R ¹ and R ² being rigid. It is also possible to use, as a polyamide-imide-based coating material, a mixture with a linear-structured polyamide-imide-based coating material. In this case, R ¹ in the compounding system,
The proportion of R ² having a rigid linear structure is 70 mol% or more,
The blending ratio of the polyamideimide-based paint to be blended may be adjusted so as to be less than 90 mol%.

If necessary, various additives such as pigments, dyes, inorganic or organic fillers and lubricants may be added to the polyamide-imide type coating used in the present invention. The insulated wire of the present invention is manufactured by applying the above-mentioned polyamide-imide-based paint to the surface of the wire and baking it to form an insulating coating.

The thickness of the insulating coating is not particularly limited in the present invention, and it can be formed to the same thickness as the conventional one, depending on the size of the electric wire and the like. Under the insulation film,
A base layer made of a material having good adhesion to the insulating coating and the electric wire may be provided. Examples of the underlayer include insulating films formed by coating and baking various conventionally known insulating coating materials such as polyurethane-based, polyester-based, polyesterimide-based, polyesteramideimide-based, polyamideimide-based, and polyimide-based. Among them, from the viewpoint of adhesion to electric wires and insulating coatings, mechanical strength of coatings, etc., it is formed by coating and baking a polyamideimide-based coating material containing diphenylmethane-4,4'-diisocyanate and trimellitic anhydride. The underlying layer is preferably used.

The film thickness of the underlayer is not particularly limited in the present invention either, but in consideration of the mechanical strength of the film and the like, the ratio of the film thickness between the insulating film and the underlayer is in the range of 1/10 to 10/1. It is preferably within. A surface lubricating layer may be provided on the upper layer of the insulating coating in order to impart lubricity to the surface of the insulating coating.

As the surface lubricating layer, coating films of paraffins such as liquid paraffin and solid paraffin can be used, but in consideration of durability, various waxes, lubricants such as polyethylene, fluororesin and silicone resin are used as binder resins. A bound surface lubricating layer is more preferred.

[0041]

EXAMPLES The insulated wire of the present invention will be described below based on Examples and Comparative Examples. Example 1 In a flask equipped with a thermometer, a cooling tube, a calcium chloride filling tube, a stirrer, and a nitrogen blowing tube, while flowing 150 ml of nitrogen gas per minute from the nitrogen blowing tube, 10
8.6 g of trimellitic anhydride (hereinafter referred to as "TMA"), 36.2 g of p-phenylene diisocyanate (hereinafter referred to as "PPDI"), and 84.8 g of diphenyl mentha-4,4'-diisocyanate (hereinafter referred to as ""MD
I "). The ratio of the total amount of TMA as the linear acid and PPDI as the linear diisocyanate to the total amount of the acid component and the diisocyanate component was 70 mol%.

Next, 637 g of N- was added to the flask.
Add methyl-2-pyrrolidone and stir with a stirrer 8
React at 0 ° C for 3 hours, then 140 ° C over 3 hours
The temperature was raised to 140 ° C. and reacted at 140 ° C. until the reduced specific viscosity of the polyamideimide became 0.52. Then, the heating was stopped and the temperature was cooled to room temperature to obtain a polyamideimide-based coating having a concentration of 15%.

This polyamide-imide type coating was prepared with a diameter of 1.
A copper wire having a thickness of 0 mm was coated and baked by a conventional method to produce an insulated electric wire having an insulating coating having a film thickness of 35 μm. Example 2 The amount of PPDI charged and the amount of MDI charged during the preparation of the polyamide-imide-based coating material were 18.1 g and 70.7 g, respectively, and 44.8 g of the diisocyanate component, 3,
3'-Dimethylbiphenyl-4,4'-diisocyanate (hereinafter referred to as "TODI") was added, and TMA as a linear acid and PPDI as a linear diisocyanate with respect to the total amount of the acid component and the diisocyanate component were added.
An insulated wire was produced in the same manner as in Example 1 except that the total ratio of and TODI was 75 mol%.
The reduced specific viscosity was 0.46.

Example 3 Instead of TODI, 35.6 g of naphthylene-1,5-diisocyanate (hereinafter referred to as “NDI”) was used, and TMA as a linear acid was added to the total amount of the acid component and the diisocyanate component. An insulated wire was produced in the same manner as in Example 2 except that the total proportion of PPDI and NDI as the linear diisocyanate was 75 mol%. The reduced specific viscosity was 0.47.

Example 4 Using 23.8 g of NDI instead of PPDI, the sum of TMA as linear acid and TODI and NDI as linear diisocyanate with respect to the total amount of acid and diisocyanate components. An insulated wire was produced in the same manner as in Example 2 except that the proportion was 75 mol%. The reduced specific viscosity was 0.58.

Example 5 The amount of PPDI charged was 27.1 g, the amount of TODI charged was 59.7 g, and the amount of MDI charged was 42.4 g. As a linear acid relative to the total amount of the acid component and the diisocyanate component, The total ratio of TMA and PPDI and TODI as linear diisocyanates is 85 mol%
An insulated wire was produced in the same manner as in Example 2 except for the above. The reduced specific viscosity was 0.56.

Comparative Example 1 PPDI was not charged during preparation of the polyamide-imide type coating material,
An insulated wire was prepared in the same manner as in Example 1 except that the amount of MDI charged was 141.4 g, and the proportion of TMA as a linear acid with respect to the total amount of the acid component and diisocyanate component was 50 mol%. It was made. The reduced specific viscosity was 0.45.

COMPARATIVE EXAMPLE 2 The amount of PPDI charged and the amount of MDI charged during the preparation of the polyamide-imide-based coating were 18.1 g and 113.1 g, respectively, and TMA as a linear acid was added to the total amount of the acid component and the diisocyanate component. An insulated wire was produced in the same manner as in Example 1 except that the total proportion of PPDI as the linear diisocyanate was 60 mol%. The reduced specific viscosity was 0.50.

Comparative Example 3 The amount of PPDI charged and the amount of MDI charged during the preparation of the polyamide-imide-based coating were 18.1 g and 28.3 g, respectively, and the TOD of 44.8 g as the diisocyanate component was used.
I and 35.6 g of NDI are added, and T as a linear acid is added to the total amount of the acid component and the diisocyanate component.
MA and PPDI, T as a linear diisocyanate
An insulated wire was produced in the same manner as in Example 1 except that the total ratio of ODI and NDI was 90 mol%. The reduced specific viscosity was 0.48.

The following tests were conducted on the insulated wires of the above Examples and Comparative Examples. Tensile Elastic Modulus, Tensile Strength Measurement Copper wires were removed from the insulated electric wires of Examples and Comparative Examples by etching, and the remaining insulating coating (length 6 cm) was measured using a tensile tester with a chuck spacing of 3 cm and a pulling speed of 1 mm / Tensile test was carried out under the conditions of minutes, and the tensile modulus (kg / mm
² ) and tensile strength (kg / mm ² ) were determined.

Flexibility test Insulated electric wires of Examples and Comparative Examples were manufactured with a diameter of 1 mm to 1 mm.
No damage was observed in the insulation coating when the wires were bent in accordance with the outer shape of the round rod by sequentially applying multiple round rods whose diameters gradually increased. The smallest round bar diameter d (mm) was recorded.

Measurement of Leakage Current after Winding The insulated wires of Examples and Comparative Examples were wound into a coil using a stator-type insert winding machine, and then immersed in 3% saline solution together with a counter electrode to form a coil. A direct current voltage of 3 V was applied between the negative electrode and the counter electrode to measure the leakage current value, and the size of the scratches reaching the conductor on each electric wire was evaluated.

The above results are shown in Table 1.

[0054]

[Table 1]

From the results in Table 1 above, the proportion of the linear acid and diisocyanate is less than 70 mol% based on the total amount of the acid component and diisocyanate component, and R ¹ and R ² in the general formula (1) are The proportion of rigid linear structure is
Comparative Examples 1 and 2 each having an insulating coating made of polyamide imide of less than 70 mol% in total have low tensile elastic modulus and tensile strength, and have a large leakage current value after winding. Was found to be easily damaged. The proportion of the linear acid and diisocyanate is 90 mol% based on the total amount of the acid component and diisocyanate component, and R ¹ and R ² in the general formula (1) are
Comparative Example 3 having an insulating coating made of polyamide-imide in which the proportion of rigid linear structure is 90 mol% in total.
It was found that the insulating coating was hard and brittle because of poor flexibility and low tensile strength.

On the other hand, it was found that the insulated wires of Examples 1 to 5 each had an insulating coating which was less likely to be damaged and was more flexible than the above-mentioned comparative examples. Example 6 An insulated wire was produced in the same manner as in Example 2 except that the reaction was continued until the reduced specific viscosity of polyamideimide reached 0.7.

Comparative Example 4 An insulated wire was produced in the same manner as in Example 2 except that the reaction was stopped when the reduced specific viscosity of the polyamideimide reached 0.35. Regarding the above Examples and Comparative Examples,
Each of the above tests was performed. The results are shown in Table 2 together with the results of Example 2.

[0058]

[Table 2]

From the results shown in Table 2 above, the reduced specific viscosity was 0.4.
Comparative Example 4 having an insulating coating made of polyamide-imide of less than 0.35 has a low tensile elastic modulus and tensile strength and a large leakage current value after winding, and therefore the insulating coating is easily damaged. I found out. On the other hand, it was found that the insulated wires of Examples 2 and 6 each had an insulating coating that was less likely to be damaged and was more flexible than Comparative Example 4 described above.

Further, comparing the results of Examples 2 and 6,
It was also found that Example 6 having a higher reduced specific viscosity had a higher strength of the insulating coating than Example 2 and was less likely to be damaged. Example 7 The amount of TMA charged during the preparation of the polyamide-imide-based coating was 8
6.8 g, 18.8 g of isophthalic acid (hereinafter referred to as "IPA") was added as an acid component, and the amount of PPDI charged as a diisocyanate component was 27.1.
g, the amount of TODI charged was 30.0 g, and TMA as a linear acid and PP as a linear diisocyanate with respect to the total amount of the acid component and the diisocyanate component
80 mol% of the total ratio of DI, TODI and NDI
An insulated electric wire was produced in the same manner as in Comparative Example 3 except that The reduced specific viscosity was 0.44.

The above-mentioned tests were carried out on the above-mentioned examples. The results are shown in Table 3 together with the results of Comparative Example 3.

[0062]

[Table 3]

From the results of Table 3 above, IPA as an acid component having a bent portion in the molecule was added, and the mixing ratio of the linear acid and diisocyanate to the total amount of the acid component and diisocyanate component was less than 90%. It has been found that the flexibility and tensile strength of the insulating coating can be improved by decreasing the value to 10. Example 8 The following acid component and diamine component were added to a flask equipped with a thermometer, a cooling tube, a calcium chloride filling tube, a stirrer, and a nitrogen blowing tube while flowing 150 ml of nitrogen gas per minute from the nitrogen blowing tube. Was thrown in. -Acid component: TMA = 1.0 mol-Diamine component: p-phenylenediamine (hereinafter referred to as "p-PDA")
= 0.3 mol 4,4'-diaminodiphenyl ether (hereinafter referred to as "DD
E ") = 0.2 mol Next, N-methyl-2-pyrrolidone was put into the flask and heated at 100 ° C. for 2 hours while stirring with a stirrer. Then, after the lapse of 2 hours, the heating was stopped and the mixture was allowed to cool to produce a dicarboxylic acid.

Next, after purifying this dicarboxylic acid by a conventional method, 0.5 mol of the dicarboxylic acid and the following diisocyanate component were placed in the same reaction vessel as above. Diisocyanate component: PPDI = 0.1 mol NDI = 0.1 mol MDI = 0.3 mol Next, N-methyl-2-pyrrolidone was put into the flask and stirred from room temperature for 3 hours while stirring with a stirrer. Over 1
It heated up to 40 degreeC and heated at 140 degreeC for 1 hour. Then, when 1 hour had passed, the heating was stopped and the mixture was allowed to cool to obtain a polyamideimide-based coating material having a concentration of 25%. Of the total amount of TMA as a linear acid, p-PDA as a linear diamine, and PPDI and NDI as a linear diisocyanate with respect to the total amount of the acid component as a raw material, the diamine component and the diisocyanate component. The ratio was 75 mol% and the reduced specific viscosity was 0.46.

Using this polyamide-imide type paint,
In the same manner as in Example 1, an insulated wire having a thickness of 35 mm and an insulating coating film on the surface of a copper wire having a diameter of 1.0 mm was produced. Example 9 A flask equipped with a thermometer, a cooling tube, a calcium chloride filling tube, a stirrer, and a nitrogen blowing tube was charged with the following acid component and diamine component while flowing 150 ml of nitrogen gas per minute from the nitrogen blowing tube. Was thrown in. -Acid component: trimellitic acid chloride (hereinafter referred to as "TMC") =
0.5 mol-diamine component: 4,4'-diaminobenzanilide (hereinafter referred to as "DABA
N ”) = 0.15 mol p-PDA = 0.15 mol 4,4′-diaminodiphenyl ether (hereinafter referred to as“ DD ”).
E ") = 0.20 mol Next, N-methyl-2-pyrrolidone was put into the flask so that the solid content concentration became 25%, and the mixture was stirred with a stirrer at 80 ° C. for 2 hours, then. The reaction was carried out at 140 ° C for 2 hours.

Next, the above reaction solution was added to a large amount of water,
After removing hydrochloric acid as a by-product, the polyamideimide precipitated in water was filtered off. Then, the filtered polyamide imide was washed with water several times, dried at 100 ° C. for 3 hours, and then again dissolved by adding N-methyl-2-pyrrolidone so that the solid content concentration became 25%. A polyamideimide-based paint was obtained. T as a linear acid chloride based on the total amount of the acid component and the diamine component as raw materials
MC and p-PDA and D as linear diamines
The total proportion of ABAN is 80 mol%, and the reduced specific viscosity is 0.
It was 43.

Using this polyamide-imide type paint,
In the same manner as in Example 1, an insulated wire having a thickness of 35 mm and an insulating coating film on the surface of a copper wire having a diameter of 1.0 mm was produced. Each of the above-mentioned tests was performed on both of the above-mentioned examples. The results are shown in Table 4.

[0068]

[Table 4]

From the results of Table 4 above, even when the polyamide-imide-based coating material produced by the above-mentioned manufacturing method is used, it is less likely to be damaged as in each of the above-mentioned examples using the polyamide-imide-based coating material manufactured by the manufacturing method. It was found that an insulated wire having an insulating coating having excellent flexibility can be manufactured.

[0070]

According to the insulated wire of the present invention, a rigid linear structure is introduced into the structure of polyamide-imide, and
By increasing the reduced specific viscosity, which indicates the molecular weight, an insulating coating having excellent flexibility and being less likely to be damaged could be formed. Therefore, the insulated wire of the present invention has excellent workability,
For example, when it is used for winding a motor, even if the winding amount to the core is increased more than before, there is no risk of damage to the insulation coating during the winding process, and it is possible to meet the demand for a motor that is smaller, lighter and has better performance. can do.

Claims (1)

[Claims] 1. General formula (1): And R ¹ and R in the formula
70 mol% or more and less than 90 mol% of the total of ² has a rigid straight-chain structure, and the reduced specific viscosity indicating the molecular weight is 0.
An insulated wire having an insulating coating formed by applying and baking a polyamide-imide-based coating material containing a polyamide-imide of 4 or more.