JP2012251150A - Polyamideimide resin insulation coating material and insulation wire using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyamideimide resin insulation coating material which has a high partial discharge inception voltage by achieving a low dielectric constant while maintaining heat resistance, mechanical properties, oil resistance, etc., and to provide an insulation wire using the same.SOLUTION: The polyamideimide resin insulation coating material is obtained by dissolving in a polar solvent, a polyamideimide resin not containing a halogen atom in the molecular chain. The polyamideimide resin is obtained by: blending an aromatic diisocyanate component (B) having two or less benzene rings to an aromatic imide prepolymer including an amine component comprising only an aromatic diamine component (E) having three or more benzene rings and an acid component comprising an aromatic tricarboxylic acid anhydride (C) and an aromatic tetracarboxylic acid dianhydride (D) as a monomer; and reacting them. The ratio M/N of a molecular weight (M) per repeating unit of the polyamideimide resin to average pieces (N) of amide groups and imide groups is 200 or more.

Description

  The present invention relates to a polyamide-imide resin insulating paint, and more particularly to a low-dielectric-constant polyamide-imide resin insulating paint obtained from a relatively high molecular weight monomer containing three or more benzene rings, and an insulated wire using the same.

  In recent years, hybrid vehicles have begun to spread with the background of energy saving, and drive motors are driven by inverters to improve fuel efficiency and power performance, and miniaturization, weight reduction, high heat resistance, and high voltage drive are rapidly progressing.

  The enameled wire currently used in this motor coil is excellent in heat resistance, mechanical characteristics that can withstand harsh coil forming, or mission oil resistance in order to meet the requirements of motor performance such as small size, light weight, and high heat resistance. A polyamide-imide enameled wire that combines the above is indispensable. However, with respect to the mission oil resistance, the insulation retention is greatly affected by the type and amount of the oil additive, but the hydrolyzability due to water content is directly linked to the mission oil resistance except for the influence of the oil additive.

  For higher voltage drive, combined with inverter surge superposition, there is an increased risk of partial discharge, making it difficult to cope with inverter surge insulation.

  Polyamideimide resin insulating paints are generally polar solvents such as N-methyl-2-pyrrolidone (NMP), N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAC), dimethylimidazolidinone (DMI), etc. Inside, 4,4'-diphenylmethane diisocyanate (MDI) and trimellitic anhydride (TMA) are mainly decarboxylated by two components, and amide groups and imide groups are formed in almost half ratio, and heat resistance It is a heat-resistant polymer resin that exhibits excellent properties such as mechanical properties and hydrolysis resistance.

  For example, an isocyanate method or an acid chloride method is known for producing a polyamide-imide resin insulating paint. From the viewpoint of production productivity, the isocyanate method is generally used. As an example of the polyamide-imide resin, one obtained by a synthesis reaction mainly of two components of 4,4'-diphenylmethane diisocyanate (MDI) and trimellitic anhydride (TMA) as an acid component is best known.

  In addition, in order to modify the properties of the polyamideimide resin, an aromatic diamine and an aromatic tricarboxylic acid anhydride are reacted in an acid excess of 50/100 to 80/100, and then a polyamideimide resin is synthesized with a diisocyanate component. There is a method to do (see Patent Document 1).

  On the other hand, one of the drawbacks of a film made of polyamide-imide resin insulating paint is that the dielectric constant is high, and the presence of amide groups and imide groups has the greatest influence on the increase in dielectric constant in terms of the resin structure.

  Insulated wires, especially enameled wires used in motor coils, are often driven by inverters for higher efficiency, and excessive discharge (inverter surge) causes partial discharge deterioration, leading to dielectric breakdown. There are many cases. In addition, the motor drive voltage tends to increase, and the risk of occurrence of partial discharge is further increased.

  As a technique for improving the charging life against partial discharge, a partial discharge resistant enamel wire produced by applying a partial discharge resistant resin paint obtained by dispersing organosilica sol in a resin solution onto a conductor is disclosed. (For example, see Patent Documents 2 and 3).

  As another method, there is a method in which an electric field between lines (an electric field applied to an air layer existing between the lines) is relaxed to make it difficult for partial discharge to occur, thereby improving the electric life.

  As a method therefor, there are a method of relaxing the electric field by imparting conductivity or semiconductivity to the surface of the electric wire and a method of relaxing the electric field by reducing the dielectric constant of the insulating film.

Japanese Patent No. 2897186 Japanese Patent No. 3396636 JP 2004-204187 A

  In the method of making the surface of the insulated wire conductive or semiconductive, there are many problems such as the occurrence of scratches during coil winding, which may cause the insulation characteristics to deteriorate and the terminal portion to be insulated. The practicality is low. On the other hand, in the method of reducing the dielectric constant of the insulating film, since the reduction of the dielectric constant depends on the resin structure, it generally causes adverse effects on heat resistance and mechanical characteristics. Improvement was difficult.

  In the method of Patent Document 1, the first stage 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) and trimellitic anhydride (TMA) are mixed with 50/100 acid excess. When the reaction is carried out under the condition, the mixing ratio is appropriate, so that the reaction with the amino group is preferentially reacted with the acid anhydride rather than the carboxylic acid. A bistrimeric imide is formed.

  However, when the BAPP is more than 50, the reaction between the amino group and the carboxylic acid of TMA is very difficult to proceed. Therefore, even when the synthesis reaction is performed at 200 ° C. near the boiling point of NMP or the like, the amino group remains, The amino group and the isocyanate group formed a urea bond during the synthesis reaction in the second stage, and there was a defect that the characteristics deteriorated.

  On the other hand, when the ratio is less than 50, acid anhydride remains during the first-stage reaction, water accompanying the imidization reaction remains in the system, and the acid anhydride becomes carboxylic acid, resulting in a significant decrease in reactivity.

  These deteriorations in characteristics have a problem in that the blending balance of these functional groups is not appropriate.

  Therefore, if a polyamideimide having a low dielectric constant can be produced, an excellent enameled wire that can cope with high voltage driving can be provided.

  Therefore, an object of the present invention is to use a high molecular weight monomer containing an aromatic diamine component having three or more benzene rings in the synthesis of a polyamideimide resin insulating coating, Reducing the number of amide groups and imide groups to reduce the dielectric constant while maintaining heat resistance, mechanical properties, oil resistance, etc. Is to provide.

  In order to solve the above problems, the invention of claim 1 is a polyamide-imide resin insulating paint obtained by dissolving a polyamide-imide resin not containing a halogen element in a molecular chain in a polar solvent. Containing an amine component consisting only of an aromatic diamine component (E) having one or more benzene rings, and an acid component consisting of an aromatic tricarboxylic acid anhydride (C) and an aromatic tetracarboxylic acid dianhydride (D). The aromatic imide prepolymer is mixed with an aromatic diisocyanate component (B) having two or less benzene rings and reacted to obtain a molecular weight (M) per repeating unit of the polyamide-imide resin and an amide group. And a polyamide-imide resin insulating paint characterized in that the ratio M / N to the average number (N) of imide groups is 200 or more. That.

  In the invention of claim 2, the blending ratio of the aromatic tricarboxylic acid anhydride (C) to the aromatic tetracarboxylic dianhydride (D) is C / D = 95 / 5-60 / 40 (moles). The polyamide-imide resin insulating paint according to claim 1.

  An invention according to claim 3 is an insulated wire characterized in that a film formed by applying and baking the polyamide-imide resin insulating paint according to claim 1 or 2 on a conductor or on another insulating film is formed. is there.

  As described above, the polyamideimide resin insulating paint of the present invention contains the aromatic diamine component (E) having three or more benzene rings in the monomer of the polyamideimide resin, and per polyamideimide resin repeating unit. By setting the ratio M / N of the molecular weight (M) and the average number of amide groups and imide groups (N) to 200 or more, the polymer of the amide group and imide group that has the greatest influence on the increase in dielectric constant The dielectric constant can be reduced by reducing the existence ratio.

  In addition, when aromatic diamine (E) is used, it is synthesized by combining aromatic tricarboxylic anhydride (C) and aromatic tetracarboxylic dianhydride (D) as an acid component. The formation of a urea bond due to the reaction between the residual amino group described in 1 and an isocyanate group can be suppressed.

  By using the polyamide-imide resin insulating paint according to the present invention, the partial discharge start voltage can be improved by lowering the dielectric constant while maintaining the same characteristics as a general-purpose polyamide-imide enameled wire composed of MDI and TMA. it can.

It is sectional drawing of the insulated wire which has a membrane | film | coat formed by apply | coating the polyamide imide resin insulation coating in this invention.

  Hereinafter, a preferred embodiment of the polyamide-imide resin insulating paint in the present invention will be described in detail.

  The present invention relates to a polyamide-imide resin insulating paint obtained by dissolving a polyamide-imide resin containing no halogen element in a molecular chain in a polar solvent, wherein the polyamide-imide resin is an aromatic diisocyanate having three or more benzene rings as monomers. The component M contains a component (A) or an aromatic diamine component (E), and the ratio M / N between the molecular weight (M) per repeating unit of the polyamide-imide resin and the average number of amide groups and imide groups (N) is 200. The polyamide-imide resin insulating paint as described above, and the polyamide-imide resin comprises the aromatic diisocyanate component (A), the aromatic diisocyanate component (B) having two or less benzene rings, and the aromatic tricarboxylic acid anhydride. An acid component formed by using the compound (C) alone or in combination with the aromatic tetracarboxylic dianhydride (D); Or an aromatic containing the aromatic diamine component (E) and an acid component composed of an aromatic tricarboxylic anhydride (C) and an aromatic tetracarboxylic dianhydride (D) The imide prepolymer is mixed with an aromatic diisocyanate component (B) having two or less benzene rings.

  The polyamideimide resin insulating coating used in the present invention performs solution polymerization using a polar solvent such as N-methyl-2-pyrrolidone (NMP) as a main solvent.

  Solvents include γ-butyrolactone, N, N-dimethylacetamide (DMAC), N, N-dimethylformamide (DMF), dimethylimidazolidinone (DMI), cyclohexanone, methylcyclohexanone, etc. in addition to NMP as the main solvent. It may be synthesized using a solvent that does not inhibit the synthesis reaction of the polyamideimide resin, or may be diluted.

  In addition, aromatic alkylbenzenes may be used in combination for dilution purposes. However, it is necessary to consider when there is a risk of lowering the solubility of the polyamideimide.

  From the viewpoint of characteristics and cost, the polyamide-imide resin most commonly used for enameled wire applications is 4,4'-diphenylmethane diisocyanate (MDI) as the isocyanate component (B) and trimellitic acid as the acid component (C). Two components, mainly anhydride (TMA), are used.

  In general, MDI and TMA are synthesized in equal amounts, but the isocyanate component may be synthesized in a slight excess in the range of 1 to 1.05. This slight isocyanate mixing may be performed in the same manner in the reaction using the isocyanate of the present invention.

  Examples of the diisocyanate component (B) having two or less benzene rings include the above-mentioned 4,4′-diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), naphthalene diisocyanate, and xylylene diisocyanate which are used for general purposes. And aromatic diisocyanates such as biphenyl diisocyanate, diphenylsulfone diisocyanate, diphenyl ether diisocyanate, isomers, and multimers. If necessary, aliphatic diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and xylylene diisocyanate, or alicyclic diisocyanates and isomers hydrogenated with the aromatic diisocyanates exemplified above may be used and used together. May be.

  Examples of the aromatic diisocyanate component (A) having three or more benzene rings include 2,2-bis [4- (4-isocyanatophenoxy) phenyl] propane (BIPP), bis [4- (4-isocyanate). Phenoxy) phenyl] sulfone (BIPS), bis [4- (4-isocyanatophenoxy) phenyl] ether (BIPE), full orange isocyanate (FDI), 4,4′-bis (4-isocyanatophenoxy) biphenyl, 1,4- Examples include bis (4-isocyanatophenoxy) benzene, and these isomers are also included. In these, an aromatic diisocyanate is produced using an aromatic diamine component having three or more benzene rings exemplified below. The production method is not particularly limited, but a method using phosgene is industrially most suitable and desirable.

  Examples of the aromatic diamine component (E) having three or more benzene rings include 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAIPP), bis [4- (4-amino Phenoxy) phenyl] sulfone (BAPS), bis [4- (4-aminophenoxy) phenyl] ether (BAPE), fluorenediamine (FDA), 4,4′-bis (4-aminophenoxy) biphenyl, 1,4- Examples include bis (4-aminophenoxy) benzene, and these isomers are also included.

  There is trimellitic anhydride (TMA) as the aromatic tricarboxylic acid anhydride (C) of the acid component. In addition, aromatic tricarboxylic acid anhydrides such as benzophenone tricarboxylic acid anhydride can be used, but TMA is most preferable.

  When synthesizing using aromatic diamine (E) having three or more benzene rings, aromatic tricarboxylic acid anhydrides (C) and tetracarboxylic dianhydrides (D) are used in combination. It is desirable to do.

  As tetracarboxylic dianhydride (D), pyromellitic dianhydride (PMDA), 3,3′4,4′-benzophenonetetracarboxylic dianhydride (BTDA), 3,3′4,4 ′ -Diphenylsulfonetetracarboxylic dianhydride (DSDA), 4,4'-oxydiphthalic dianhydride (ODPA), 3,3'4,4'-biphenyltetracarboxylic dianhydride, etc. are exemplified and necessary Depending on the above, butanetetracarboxylic dianhydride, 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, or the aromatic exemplified above You may use together alicyclic tetracarboxylic dianhydride etc. which hydrogenated tetracarboxylic dianhydride.

  When used together with alicyclic structure raw materials, it is expected to have an effect on reducing the dielectric constant and improving the transparency of the resin composition, so it may be used together as necessary, but it may cause a decrease in heat resistance. Consideration of the structure is necessary.

  The blending ratio of the aromatic diisocyanate component (A) having three or more benzene rings, the aromatic tricarboxylic anhydride (C) and the aromatic tetracarboxylic dianhydride (D) is A / (C + D) = 50. / 100 to 70/100 (molar ratio) is desirable.

  The blending ratio of the aromatic diamine component (E) having three or more benzene rings, the aromatic tricarboxylic anhydride (C) and the aromatic tetracarboxylic dianhydride (D) is E / (C + D) = 51 / 100 to 70/100 (molar ratio) is desirable. When the aromatic diisocyanate component (A) is less than 50 and the aromatic diamine component (E) is less than 51, the acid anhydride remains during the first stage reaction, the water accompanying the imidization reaction remains in the system, and the acid anhydride remains. Since it becomes carboxylic acid and the reactivity is remarkably lowered, it is not preferable. If it exceeds 70, the compounding ratio of the aromatic tetracarboxylic dianhydride (D) inevitably increases, the imide group greatly increases, and excellent properties such as the mechanical properties of the polyamideimide resin resulting from the amide group are present. Deteriorating and not preferable.

  The ratio of the aromatic tricarboxylic acid anhydride (C) to the aromatic tetracarboxylic dianhydride (D) is also preferably C / D = 100/0 to 60/40.

  The ratio M / N between the molecular weight per repeating unit of the polyamideimide resin (M = weight average molecular weight Mw) and the total number of amide groups and imide groups (N) is preferably 200 or more.

  The lower the relative dielectric constant, the better. However, in order to exhibit effectiveness in inverter surge insulation, 3.5 or less is desirable.

  At the time of synthesizing the polyamideimide resin insulating paint, a reaction catalyst such as amines, imidazoles, and imidazolines may be used, but those that do not inhibit the stability of the paint are desirable. A sealing agent such as alcohol may be used when the synthesis reaction is stopped.

  Reference Examples 1 to 7 and Comparative Examples 1 to 3 and 7 are syntheses of polyamideimide resin insulating paints using a diisocyanate component (A) as a monomer of polyamideimide resin, and are similar to the synthesis of ordinary polyamideimide resin paints. It carried out as follows.

  Into a flask equipped with a stirrer, a reflux condenser, a nitrogen inlet pipe, and a thermometer, the raw materials and solvents shown in Examples 1 to 7 and Comparative Examples 1 to 3 were charged at a time and stirred for about 1 hour in a nitrogen atmosphere. The mixture was heated to 140 ° C. and reacted at this temperature for 2 hours so that a polyamideimide resin solution having a reduced viscosity of about 0.5 dl / g was obtained.

  Examples 1-7 and Comparative Examples 4-6 are the synthesis | combination of the polyamide-imide resin insulation coating which used the diamine component (E) for the monomer of the polyamide-imide resin, and implemented the two-step synthesis | combination as follows.

  Prepare a flask equipped with a stirrer, a reflux condenser, a nitrogen inlet pipe, and a thermometer, and as a first-stage synthesis reaction, the diamine component (E) shown in Examples 1 to 7 and Comparative Examples 4 to 6, and Aromatic tricarboxylic acid anhydride (C) and aromatic tetracarboxylic dianhydride (D), which are acid components, and about 50 to 80% of the solvent are added, and the mixture is stirred at 180 ° C. for about 1 hour in a nitrogen atmosphere. Until the water produced by the dehydration reaction was taken out of the system, the reaction was carried out at this temperature for 4 hours. After cooling to 60 ° C. while maintaining the nitrogen atmosphere, the diisocyanate component (B) and the remaining solvent are added, and the second stage synthesis reaction is heated to 140 ° C. in about 1 hour with stirring in the nitrogen atmosphere. In order to obtain a polyamideimide resin solution having a reduced viscosity of about 0.5 dl / g, the reaction was carried out at this temperature for 2 hours.

  The polyamideimide resin insulating coating was applied and baked onto a 0.8 mm copper conductor to obtain an enameled wire having an insulating film with a film thickness of 45 μm.

  FIG. 1 is a view showing an insulated wire formed by applying a polyamide-imide resin insulating paint according to the present invention.

  An insulating coating 2 is obtained around the conductor 1 by applying and baking a polyamide-imide resin insulating paint on the conductor 1.

  Alternatively, another insulating film may be formed directly on the conductor 1, and the film 2 made of the polyamide-imide resin insulating paint of the present invention may be formed thereon. At this time, the other insulating film is not particularly limited as long as it does not impair partial discharge resistance or general characteristics.

  Properties in Examples, Reference Examples and Comparative Examples, characteristics of the enamel wire obtained, etc. are shown in Tables 1 to 3.

  In addition, the characteristic of the enameled wire was measured by a method based on JIS.

  Hydrolysis resistance is as follows: an enameled wire twisted with 0.4 mL of water is put into a heat-resistant glass tube with an internal volume of 400 mL, then heated and melted and sealed with a burner or the like in a constant temperature bath at 140 ° C. for 1000 h. After the treatment, the product was taken out, the dielectric breakdown voltage was measured, and the residual ratio relative to the untreated dielectric breakdown voltage was calculated.

  For the relative dielectric constant, a metal electrode was deposited on the surface of the enameled wire, the capacitance between the conductor and the metal electrode was measured, and the relative dielectric constant was calculated from the relationship between the electrode length and the film thickness. The capacitance was measured at 1 kHz using an impedance analyzer. The dielectric constant at the time of drying was measured in a constant temperature bath at 100 ° C., and the dielectric constant at the time of moisture absorption was left in a constant temperature and humidity chamber at 25 ° C.-50% RH for 50 hours.

  The partial discharge start voltage was measured by measuring the discharge start voltage at a detection sensitivity of 10 pC at 50 Hz after standing for 50 hours in a thermostatic chamber at 25 ° C.-50% RH.

(Reference Example 1)
As an aromatic diisocyanate component (A) having 3 or more benzene rings, 231.0 g (0.5 mol) of BIPP (Mw = 462) and 125 or less as an aromatic diisocyanate component (B) having 2 or less benzene rings 0.04 g (0.5 mol) 4,4′-MDI (Mw = 250), 192.0 g (1.0 mol) TMA (Mw = 192) as aromatic tricarboxylic anhydride (C) and as solvent 1600 g of NMP was added and synthesis was carried out at 140 ° C. to obtain a polyamideimide resin insulating paint having a reduced viscosity of about 0.5 dl / g and a resin concentration of about 25% by weight.

(Reference Example 2)
As aromatic diisocyanate component (A) having three or more benzene rings, 242.6 g (0.525 mol) of BIPP and aromatic diisocyanate component (B) having two or less benzene rings as 118.8 g (0 .475 mol) 4,4′-MDI, 182.4 g (0.95 mol) TMA as aromatic tricarboxylic anhydride component (C) and 10.4 as aromatic tetracarboxylic dianhydride component (D). 9 g (0.05 mol) of PMDA (Mw = 218) and 1600 g of NMP as a solvent were added and synthesized at 140 ° C., the reduced viscosity was about 0.5 dl / g, and the resin concentration was about 25% by weight. A polyamide-imide resin insulating paint was obtained.

(Reference Example 3)
As aromatic diisocyanate component (A) having 3 or more benzene rings, 338.8 g (0.7 mol) of BIPS (Mw = 484) and 62 or less as aromatic diisocyanate component (B) having 2 or less benzene rings .5 g of 4,4′-MDI (Mw = 250) and 12.5 g of 2,4′-MDI (Mw = 250) in total 75.0 g (0.3 mol) of MDI, aromatic tricarboxylic acid anhydride 115.2 g (0.6 mol) TMA as component (C) and 143.2 g (0.4 mol) DSDA (Mw = 358) as aromatic tetracarboxylic dianhydride component (D) and 2000 g as solvent. NMP was added and synthesized at 140 ° C. to obtain a polyamideimide resin insulating paint having a reduced viscosity of about 0.5 dl / g and a resin concentration of about 25% by weight.

(Reference Example 4)
As aromatic diisocyanate component (A) having 3 or more benzene rings, 239.8 g (0.55 mol) of BIPE (Mw = 436) and 112 or less as aromatic diisocyanate component (B) having 2 or less benzene rings 0.5 g (0.45 mol) of 4,4′-MDI, 172.8 g (0.9 mol) of TMA as aromatic tricarboxylic anhydride component (C) and aromatic tetracarboxylic dianhydride component (D ) 32.2 g (0.1 mol) of BTDA (Mw = 322) and 1600 g of NMP as a solvent were added and synthesized at 140 ° C., the reduced viscosity was about 0.5 dl / g, and the resin concentration was about A 25% by weight polyamideimide resin insulating paint was obtained.

(Reference Example 5)
As the aromatic diisocyanate component (A) having three or more benzene rings, 219.5 g (0.475 mol) BIPP and 40.0 g (0.1 mol) FDI (Mw = 400) were used in combination. As the aromatic diisocyanate component (B) having the following benzene rings, 106.3 g (0.425 mol) of 4,4′-MD1 and 163.2 g (0.85 mol) of aromatic tricarboxylic acid anhydride component (C) ) And 46.5 g (0.15 mol) of ODPA (Mw = 310) as the aromatic tetracarboxylic dianhydride component (D) and 1700 g of NMP as the solvent, and synthesis at 140 ° C. A polyamide-imide resin insulating paint having a reduced viscosity of about 0.5 dl / g and a resin concentration of about 25% by weight was obtained.

(Reference Example 6)
As the aromatic diisocyanate component (A) having three or more benzene rings, 138.6 g (0.3 mol) of BIPP and 175.0 g (0. 7 mol) of 4,4′-MDI, 192.0 g (1.0 mol) of TMA as aromatic tricarboxylic acid anhydride (C) and 1200 g of NMP as solvent were added and synthesized at 140 ° C. Then, 300 g of DMF was diluted to obtain a polyamide-imide resin insulating paint having a reduced viscosity of about 05 dl / g and a resin concentration of about 25% by weight.

(Reference Example 7)
305.2 g (0.7 mol) of BIPE as an aromatic diisocyanate component (A) having 3 or more benzene rings and 75.0 g (0. 2) as an aromatic diisocyanate component (B) having 2 or less benzene rings. 3 mol) of 4,4′-MDI, 192.0 g (1.0 mol) of TMA as an aromatic tricarboxylic acid anhydride (C) and 1350 g of NMP as a solvent were added and synthesized at 140 ° C. Then, 350 g of DMF was added and diluted to obtain a polyamide-imide resin insulating paint having a reduced viscosity of about 0.5 dl / g and a resin concentration of about 25% by weight.

Example 1
As the synthesis of the first stage, 215.3 g (0.525 mol) of BAPP (Mw = 410) as an aromatic diamine component (E) having three or more benzene rings, an aromatic tricarboxylic acid anhydride component (C ) 182.4 g (0.95 mol) of TMA, 10.9 g (0.05 mol) of PMDA as aromatic tetracarboxylic dianhydride component (D) and 1000 g of NMP as solvent, The synthesis was carried out while discharging water outside the system at ℃, and after cooling to 60 ℃ while maintaining the nitrogen atmosphere, as the synthesis of the second stage, 118.8 g (0.475 mol) as the aromatic diisocyanate component (B) ), 4,4'-MDI and 600 g of NMP as a solvent, synthesized at 140 ° C., reduced viscosity of about 0.5 dl / g, resin concentration of about 25 wt% polyamide An imide resin insulating paint was obtained.

(Example 2)
As the synthesis of the first stage, 237.6 g (0.55 mol) of BAPS (Mw = 432) as an aromatic diamine component (E) having three or more benzene rings, an aromatic tricarboxylic acid anhydride component (C 172.8 g (0.9 mol) of TMA, 32.2 g (0.1 mol) of BTDA as aromatic tetracarboxylic dianhydride component (D), and 1000 g of NMP as solvent, The synthesis was carried out while discharging water outside the system at 0 ° C., and after cooling to 60 ° C. while maintaining the nitrogen atmosphere, 78.3 g (0.45 mol) as the aromatic diisocyanate component (B) was synthesized as the second stage synthesis. ) 2,4-TDI (Mw = 174) and 500 g of NMP as a solvent were added and synthesized at 140 ° C., and the reduced viscosity was about 0.5 dl / g and the resin concentration was about 25% by weight. It was obtained Midoimido resin insulating coating material.

(Example 3)
As the synthesis of the first stage, 302.4 g (0.7 mol) of BAPS as the aromatic diamine component (E) having three or more benzene rings, and 115.2 g as the aromatic tricarboxylic acid anhydride component (C) (0.6 mol) of TMA, 143.2 g (0.4 mol) of DSDA as aromatic tetracarboxylic dianhydride component (D) and 1200 g of NMP as a solvent were added to the system at 180 ° C. After synthesizing while discharging water and cooling to 60 ° C. while maintaining the nitrogen atmosphere, as the second stage synthesis, 75.0 g (0.3 mol) of 4,4 as the aromatic diisocyanate component (B) '-MDI and 700 g of NMP as a solvent were added and synthesized at 140 ° C. to obtain a polyamideimide resin insulating paint having a reduced viscosity of about 0.5 dl / g and a resin concentration of about 25% by weight.

Example 4
As the synthesis of the first stage, 220.8 g (0.575 mol) of BAPE (Mw = 384) as an aromatic diamine component (E) having three or more benzene rings, an aromatic tricarboxylic acid anhydride component (C ) 163.2 g (0.85 mol) TMA and aromatic tetracarboxylic dianhydride component (D) 46.5 g (0.15 mol) ODPA and 240 g NMP and 860 g γ-butyrolactone as solvent. Was synthesized while discharging water outside the system at 180 ° C., cooled to 60 ° C. while maintaining the nitrogen atmosphere, and then synthesized as the aromatic diisocyanate component (B) as the second stage synthesis. 3 g (0.425 mol) of 4,4′-MDI and 500 g of γ-butyrolactone as a solvent were added and synthesized at 140 ° C., and the reduced viscosity was about 0.5 dl / And resin concentration to obtain about 25 wt.% Polyamide-imide resin insulating coating material.

(Example 5)
As the synthesis of the first stage, 194.8 g (0.475 mol) of BAPP and 34.8 g (0.1 mol) of FDA (Mw = M) = aromatic diamine component (E) having three or more benzene rings. 348), 163.2 g (0.85 mol) of TMA as aromatic tricarboxylic anhydride component (C) and 46.5 g (0.15 mol) of ODPA as aromatic tetracarboxylic dianhydride component (D) Then, 240 g of NMP and 860 g of γ-butyrolactone were added as a solvent, and synthesis was performed while discharging water outside the system at 180 ° C., and after cooling to 60 ° C. while maintaining a nitrogen atmosphere, the second stage synthesis As an aromatic diisocyanate component (B), 106.3 g (0.425 mol) of 4,4′-MDI and 500 g of γ-butyrolactone as a solvent were added and mixed at 140 ° C. Was carried out, a reduced viscosity of about 0.5 dl / g, the resin concentration to obtain about 25 weight percent of the polyamide-imide resin insulating coating material.

(Example 6)
As the synthesis of the first stage, 225.5 g (0.55 mol) of BAPP as an aromatic diamine component (E) having three or more benzene rings, and 172.8 g as an aromatic tricarboxylic acid anhydride component (C) (0.9 mol) of TMA, 32.2 g (0.1 mol) of BTDA as aromatic tetracarboxylic dianhydride component (D) and 1200 g of NMP as solvent were added to the system at 180 ° C. After synthesizing while discharging water and cooling to 60 ° C. while maintaining a nitrogen atmosphere, as the second stage synthesis, 112.5 g (0.45 mol) of 4,4 as the aromatic diisocyanate component (B) '-MDI and 400 g of γ-butyrolactone as a solvent were added and synthesized at 140 ° C., and the polyamideimide resin having a reduced viscosity of about 0.5 dl / g and a resin concentration of about 25% by weight was completely synthesized. To give the paint.

(Example 7)
As the synthesis of the first stage, 163.2 g (0.425 mol) of BAPE and 34.8 g (0.1 mol) of FDA as an aromatic diamine component (E) having three or more benzene rings, aromatic 182.4 g (0.95 mol) of TMA as the tricarboxylic acid anhydride component (C), 10.9 g (0.05 mol) of PMDA as the aromatic tetracarboxylic dianhydride component (D) and 1200 g of solvent as the solvent NMP was added, synthesis was performed while discharging water outside the system at 180 ° C., and after cooling to 60 ° C. while maintaining the nitrogen atmosphere, as the second stage synthesis, 118 was added as the aromatic diisocyanate component (B). .8 g (0.475 mol) of 4,4′-MDI and 350 g of γ-butyrolactone as a solvent were added and synthesized at 140 ° C., and the reduced viscosity was about 0.5 dl / g. Degree was obtained about 25 weight percent of the polyamide-imide resin insulating coating material.

(Comparative Example 1)
(B) 250.0 g (1.0 mol) 4,4′-MDI as aromatic diisocyanate component, 192.0 g (1.0 mol) TMA as aromatic tricarboxylic acid anhydride (C) and 1300 g as solvent NMP was added and synthesized at 140 ° C. to obtain a polyamideimide resin insulating paint having a reduced viscosity of about 0.5 dl / g and a resin concentration of about 25% by weight.

(Comparative Example 2)
250.0 g (1.0 mol) of 4,4′-MDI as the aromatic diisocyanate component (B), 144.0 g (0.75 mol) of TMA and aromatic tetra as the aromatic tricarboxylic acid anhydride (C) 89.5 g (0.25 mol) of DSDA as a carboxylic acid dianhydride component (D) and 1450 g of NMP as a solvent were added and synthesized at 140 ° C., and the reduced viscosity was about 0.5 dl / g. A polyamide-imide resin insulating paint having a concentration of about 25% by weight was obtained.

(Comparative Example 3)
250.0 g (1.0 mol) of 4,4′-MDI as aromatic diisocyanate component (B), 115.2 g (0.6 mol) of TMA and aromatic tetra as aromatic tricarboxylic acid anhydride (C) 128.8 g (0.4 mol) of BTDA as a carboxylic acid dianhydride component (D) and 1900 g of NMP as a solvent were added, synthesized at 140 ° C., reduced viscosity was about 0.5 dl / g, resin content A polyamide-imide resin insulating paint having a concentration of about 25% by weight was obtained.

(Comparative Example 4)
As the synthesis of the first stage, 184.5 g (0.45 mol) of BAPP as an aromatic diamine component (E) having three or more benzene rings, and 192.0 g as an aromatic tricarboxylic acid anhydride component (C) (1.0 mol) TMA and 1200 g of NMP as a solvent were added, and synthesis was performed while discharging water outside the system at 180 ° C., and after cooling to 60 ° C. while maintaining a nitrogen atmosphere, the second stage In the synthesis, 137.5 g (0.55 mol) of 4,4′-MDI as an aromatic diisocyanate component (B) and 300 g of NMP as a solvent were added and synthesized at 140 ° C., and the reduced viscosity was about A polyamideimide resin insulating coating having a concentration of 0.5 dl / g and a resin concentration of about 25% by weight was obtained.

(Comparative Example 5)
As the synthesis of the first stage, 328.0 g (0.8 mol) of BAPP as an aromatic diamine component (E) having three or more benzene rings, and 192.0 g as an aromatic tricarboxylic acid anhydride component (C) (1.0 mol) TMA and 1200 g of NMP as a solvent were added, and synthesis was performed while discharging water outside the system at 180 ° C., and after cooling to 60 ° C. while maintaining a nitrogen atmosphere, the second stage In this synthesis, 50.0 g (0.2 mol) of 4,4′-MDI as an aromatic diisocyanate component (B) and 500 g of NMP as a solvent were added and synthesized at 140 ° C., and the reduced viscosity was about A polyamideimide resin insulating coating having a concentration of 0.5 dl / g and a resin concentration of about 25% by weight was obtained.

(Comparative Example 6)
As the synthesis of the first stage, 291.1 g (0.71 mol) of BAPP as an aromatic diamine component (E) having three or more benzene rings, and 111.4 g as an aromatic tricarboxylic acid anhydride component (C) (0.58 mol) of TMA, 150.4 g (0.42 mol) of DSDA as aromatic tetracarboxylic dianhydride component (D) and 1200 g of NMP as solvent were added to the system at 180 ° C. After synthesizing while discharging water and cooling to 60 ° C. while maintaining the nitrogen atmosphere, as the second stage synthesis, 72.5 g (0.29 mol) of 4,4 as the aromatic diisocyanate component (B) '-MDI and 600 g of γ-butyrolactone as a solvent were added and synthesized at 140 ° C., polyamideimide resin having a reduced viscosity of about 0.5 dl / g and a resin concentration of about 25% by weight. Obtain an insulation coating.

(Comparative Example 7)
As aromatic diisocyanate component (A) having 3 or more benzene rings, 87.2 g (0.2 mol) of BIPP and 200.0 g (0. 8 mol) of 4,4′-MD1, 192.0 g (1.0 mol) of TMA as aromatic tricarboxylic acid anhydride (C) and 1100 g of NMP as solvent were added and synthesized at 140 ° C. Then, 300 g of DMF was diluted to obtain a polyamide-imide resin insulating paint having a reduced viscosity of about 0.5 dl / g and a resin concentration of about 25% by weight.

  Comparative Example 1 shows a polyamide-imide enamel wire that is used for general purposes, but all of the flexibility, wear resistance, heat resistance, and hydrolysis resistance are good, but the relative dielectric constant is high. The partial discharge start voltage is low.

  On the other hand, it was confirmed that the polyamideimide enamel wires of Examples 1 to 7 and Reference Examples 1 to 7 had a low dielectric constant of 3.5 or less during drying, and the partial discharge starting voltage was improved by about 70 to 200V. General characteristics were good and comparable.

  In Comparative Examples 2 and 3, a general-purpose polyamideimide is used in combination with an aromatic tetracarboxylic dianhydride component to increase the number of imide groups. In Comparative Example 2, the decrease in dielectric constant during drying is slight. The wear resistance was slightly lowered, and the main effect could not be obtained. In Comparative Example 3, since the number of imide groups increased, the solubility deteriorated and deposited at the stage of coating.

  In Comparative Example 4, the blending ratio of BIPP is 45, but the reduced viscosity of the paint, that is, the molecular weight does not increase, the enamel film does not increase in polymer, and the flexibility and wear resistance are significantly reduced. I have. It is considered that the excess acid anhydride of TMA is converted to carboxylic acid by water in the system and the reactivity is lowered.

  In Comparative Example 5, the blending ratio of BIPP was 80, but the general characteristics were also significantly deteriorated. It seems that the characteristics as an amide imide could not be maintained because an excess amino group and an isocyanate group reacted and contained many urea bonds.

  In Comparative Example 6, the aromatic tetracarboxylic dianhydride component was used in combination, and the mixing ratio was such that there was no excess acid anhydride or amino group, but the mixing ratio of BIPP exceeded 70, so the imide ratio It is considered that the flexibility is increased and the flexibility is too strong to deteriorate the flexibility.

  In Comparative Example 7, the ratio M / N between the molecular weight (M) of the polyamideimide resin of one repeating unit and the total number (N) of amide groups and imide groups is less than 200, and the dielectric constant during drying is 3 .5 has been exceeded.

1 Conductor 2 Film

Claims (3)

  In a polyamide-imide resin insulating paint obtained by dissolving a polyamide-imide resin not containing a halogen element in a molecular chain in a polar solvent, the polyamide-imide resin is an aromatic diamine component (E) having three or more benzene rings as monomers. An aromatic imide prepolymer containing an amine component comprising only an acid component and an acid component comprising an aromatic tricarboxylic acid anhydride (C) and an aromatic tetracarboxylic dianhydride (D); Mixing and reacting the aromatic diisocyanate component (B) having a ring, the ratio of the molecular weight (M) per repeating unit of the polyamideimide resin and the average number (N) of amide groups and imide groups M / A polyamide-imide resin insulating paint, wherein N is 200 or more.   The blending ratio of the aromatic tricarboxylic acid anhydride (C) and the aromatic tetracarboxylic dianhydride (D) is C / D = 95 / 5-60 / 40 (molar ratio). The polyamide-imide resin insulating paint described in 1.   An insulated wire, wherein a film formed by applying and baking the polyamideimide resin insulating paint according to claim 1 directly on a conductor or on another insulating film is formed.

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