TW201504368A - Rectangular electric wire for motor winding of vehicle and vessel, winding coil, and motor - Google Patents

Abstract

A rectangular electric wire for motor winding of a vehicle and a vessel includes a rectangular conductor, and an insulating coating layer coating the rectangular conductor. At least one part of the insulating coating layer is a polyimide resin. The polyimide resin is obtained by imidizing a composition including a polyimide precursor. The polyimide precursor is obtained by polycondensing a diamine containing a specific structure of fixed quantity and an acid dianhydride containing a specific structure of fixed quantity.

Description

Square wire, coiled wire coil and motor for motor winding of vehicle

The present invention relates to a square wire for a motor winding of a vehicle ship. More specifically, the present invention relates to a square wire for electric motor winding of a vehicle ship using the following polyimide resin, which is prepared by containing a polyimine precursor having a specific structure. The shaped article obtained by varnish is formed by imidization. Further, the present invention relates to a winding coil and an electric motor using the above-described square electric wire.

The square conductor portion is protected by coating the surface of the metal square conductor with an insulating coating material such as a wire harness or a cable. Various types of products have been developed for insulating coating materials, and polyamide, polyamideimide, polyesterimide, and polyester imide have been used for insulating coating materials such as electric wires and motor windings. Engineering plastics such as polyimide. Among them, polyimine exhibits extremely excellent characteristics from the viewpoints of heat resistance, electrical insulating properties, mechanical strength, and the like, and is therefore used in a motor winding wire or the like which is particularly harsh in use environments.

Commercially available polyimines include: bis(4-aminophenyl)ether and isophthalic acid KAPTON, VESPEL (registered trademark, manufactured by Dupont Co., Ltd.) of tetracarboxylic dianhydride, comprising bis(4-aminophenyl)ether and 3,3',4,4'-biphenyltetracarboxylic dianhydride Polyimine (Imported trademark, manufactured by Ube Industries, Ltd.), and AURUM (registered trademark, manufactured by Mitsui Chemicals, Inc.).

Patent Document 1 discloses that a polyimide having a repeating structural unit represented by the following formula (I) is heated and melted in a temperature range of 300 ° C or more and 450 ° C or less by an extruder to coat a square conductor. And an insulated wire that is cooled and solidified to form an insulator.

In the formula (I), R represents an aliphatic group selected from a carbon number of 2 or more, a cyclic aliphatic group, a monocyclic aromatic group, a condensed polycyclic aromatic group, an aromatic group, or directly by a bridge member. a tetravalent group in a group consisting of a non-condensed polycyclic aromatic group to be joined, and X represents a divalent bond of a single bond, a sulfur atom, a thiol group, a carbonyl group, an isopropylidene group or a hexafluoroisopropylidene group. base.

Patent Document 2 discloses the use of p-phenylenediamine and 4,4'-diaminodiphenyl ether as a diamine, and the use of 3,3',4,4'-biphenyltetracarboxylic dianhydride as the acid II. Insulated wire for anhydride.

In order to obtain an insulating coating material or an insulated wire which can form an insulating film having high heat resistance and a high adhesion property of a counterpart type conductor and a low dielectric constant, it is proposed to include a repeat represented by the following general formula (II). An insulating coating of a polyimine resin of a unit and a repeating unit represented by the following formula (III).

In the formula (II), X ₁ is a tetravalent aromatic group having an aromatic ether structure represented by the following formula (IV), and Y ₁ is a divalent aromatic group having an aromatic ether structure, and the formula (III) In the formula, X ₂ is a tetravalent alicyclic group, and Y ₂ is a divalent alicyclic group containing an alicyclic structure. In the formula (II) and the formula (III), m and n are repeating numbers, respectively Is a positive integer.

[Previous Technical Literature]

[Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 2-210713

Patent Document 2: Japanese Patent Laid-Open No. Hei 7-37439

Patent Document 3: Japanese Patent Laid-Open Publication No. 2010-189510

The dramatic development of the electronics industry is supported by the development of various electronic components and raw materials for electronic components. As for the insulating raw materials, as described above, excellent raw materials have been proposed by active research and development. However, the insulating coating material for insulated electric wires requires not only excellent insulating properties or mechanical properties, but also materials having excellent low water absorbability to reduce transmission loss. Especially the harsh environment Insulated wires for motor winding of a vehicle ship are required to withstand heat resistance even in a high temperature environment. Further, the motor winding of a vehicle ship is particularly required to be small in size and high in efficiency for a winding coil of a high-power motor.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a square electric wire for a motor winding of a vehicle ship, which comprises excellent insulation properties and mechanical strength, thereby satisfying both heat resistance and low water absorption. An insulating coating that can be miniaturized when winding a coil.

As a result of intensive studies, the inventors of the present invention have found that the problems of the present invention can be solved in the following embodiments, and the present invention has been completed. In other words, the square wire for electric motor winding of the vehicle ship according to the present invention includes a square conductor and an insulating coating layer covering the square conductor, and at least a part of the insulating coating layer is a polyimide resin, and the polyimide resin It is obtained by imidating a shaped product formed of a polyimine precursor varnish comprising a composition comprising a polyimide precursor and a solvent, the polyimine precursor being obtained by using a diamine And the diamine component A represented by the chemical formula (1) at least 20 mol% or more and 56 mol% or less with respect to the total amount of the diamine, and the relative amount of the diamine The diamine component B represented by the chemical formula (2) in which the total amount of the diamine is 44 mol% or more and 80 mol% or less is a constituent component, and the acid dianhydride is at least the total amount of the acid dianhydride. 60 g% or more and 100 mol% or less of the acid dianhydride component C represented by the chemical formula (3), and a chemical formula of 0 mol% or more and 40 mol% or less based on the total amount of the acid dianhydride ( 4) The acid dianhydride component D shown is a constituent component.

(wherein X represents a single bond, an oxygen atom, a sulfur atom, a thiol group, a carbonyl group, a methylene group, an isopropylidene group or a divalent isopropyl group of hexafluoroisopropylidene)

(wherein Y represents a single bond, an oxygen atom, a sulfur atom, a thiol group, a carbonyl group, a methylene group, an isopropylidene group or a divalent group of a hexafluoroisopropylidene group)

Further, in a preferred embodiment of the square wire for winding a motor of a vehicle according to the present invention, the composition is coated into a film, heated at 5 ° C / min, and heated at 300 ° C for 1 hour in a nitrogen atmosphere. The polyimide film having a thickness of 20 μm (micrometers) to 60 μm after drying has a glass transition temperature of 290 ° C or higher, a water absorption ratio of 2.0% or less, and a tensile elongation at break of 55% or more.

Further, in a preferred embodiment of the square wire for winding a motor of a vehicle according to the present invention, the polyimine precursor is a total of the diamine component A in relation to the total of the diamine and the acid dianhydride. The total amount of the diamine component B satisfies 47.5 mol% to 52.5 mol%, and the total of the acid dianhydride component C and the acid dianhydride component D satisfies the range of 47.5 mol% to 52.5 mol%. Made.

Moreover, the square wire for the motor winding of the vehicle ship disclosed herein In a preferred embodiment, the diamine component B is 4,4'-bis(3-aminophenoxy)biphenyl described in the chemical formula (5).

Further, in a preferred embodiment of the square wire for electric motor winding of the vehicle ship disclosed herein, the diamine component A is 4,4'-diaminodiphenyl ether described in the chemical formula (6).

Further, in a preferred embodiment of the square wire for electric motor winding of the vehicle ship disclosed herein, the acid dianhydride component D is 3,3',4,4'-biphenyl four described in the chemical formula (7). Carboxylic dianhydride.

The winding coil of the present invention is obtained by winding a square electric wire for winding a motor of a vehicle ship according to the above-described embodiment.

The motor of the present invention includes the winding coil of the above embodiment.

According to the present invention, there is provided an excellent effect of providing a square electric wire for a motor winding of a vehicle ship including an insulating coating layer which has excellent insulating properties and mechanical strength, thereby satisfying both heat resistance and low water absorption. Moreover, it can be miniaturized when it is made into a coiled coil. Further, according to the present invention, in particular, it has an excellent effect of providing a raw material excellent in low water absorbability.

1‧‧‧ square wire

5‧‧‧Wind coil

10‧‧‧ square conductor

20‧‧‧Insulation coating

21‧‧‧1st insulation coating

22‧‧‧2nd insulation coating

30‧‧‧ core

Fig. 1A is a schematic cross-sectional view showing an example of a square electric wire of the present invention.

Fig. 1B is a schematic cross-sectional view showing an example of a square electric wire of the present invention.

Fig. 2 is a conceptual schematic view showing an example of a winding coil of the present invention.

Hereinafter, an example of an embodiment to which the present invention is applied will be described. Further, of course, other embodiments are also included in the scope of the present invention as long as they conform to the gist of the present invention. Moreover, the size or ratio of each member in the following drawings is set for convenience of explanation, and does not necessarily match the actual size or ratio. In the present specification, the description of the "arbitrary number A to the arbitrary number B" means a range of a number A or more and a number B or less.

The square wire for motor winding of the vehicle ship according to the present invention (hereinafter also referred to simply as "square wire") includes a square conductor having a square cross-sectional shape and an insulating coating layer covering the square conductor. The cross-sectional shape of the square wire is square as its name, and the coil conductor is formed by winding the square wire. At least a part of the insulating coating layer contains a polyimide resin which is formed by imidating a molded article obtained by the following polyimide precursor varnish.

Fig. 1A is a schematic cross-sectional view showing an example of a square electric wire of the present invention. The square electric wire 1 includes a square conductor 10 and an insulating coating layer 20 made of an insulating coating material covering the square conductor 10. Further, the insulating coating layer 20 may not be covered over the entire length of the square conductor 10, and a non-covered region may be present in a part of the square conductor 10.

The square conductor 10 is not particularly limited as long as it functions as an electric wire, and various conductive materials such as a copper wire, a nichrome wire, a stainless steel wire, a steel wire, and an aluminum wire can be used. In addition, the square conductor 10 used in the present invention may also be used in order to prevent an increase in specific resistance due to oxidation or deterioration of the above-described metal square conductor, heat generation of a square conductor, voltage drop, and the like. The surface is covered. The material used for coating is tin, zinc, nickel, silver, aluminum, solder, copper, etc., particularly preferably nickel, silver, or the like.

The thickness of the insulating coating layer 20 can be arbitrarily set according to the use, and is not particularly limited, and can be, for example, about 1 μm to 100 μm.

The insulating coating layer 20 is coated with the square conductor 10, and at least a part of the insulating coating layer 20 comprises a polyimide resin which is imidized by a ruthenium obtained from a polyimide pigment precursor varnish. And formed. An adhesion layer that is well joined to the square conductor 10 and the insulating coating layer 20 may be provided. In the example of FIG. 1A, the insulating coating layer 20 is formed of a layer of polyimide resin. However, as shown in FIG. 1B, the first insulating coating layer 21 and the second insulating coating layer 22 may be included. The insulating coating layer 20 of the laminated structure of the layer may have a multilayered structure of three or more layers. When a plurality of layers are laminated, the polyimine resin formed by using the polyimide precursor varnish of the present invention may be laminated, or may be a laminate of another insulating layer and the polyimide resin of the present invention. The other insulating layer is not particularly limited, and may be appropriately designed according to requirements, for example, a material for improving adhesion to the square conductor 10 or a material having high flexibility.

Next, a polyimine resin suitable for the insulating coating layer of the square electric wire of the present invention and a polyimine precursor varnish forming the polyimine resin will be described. The polyamidiene precursor varnish of the present invention contains a polyimide precursor and The composition of the solvent. Further, the polyimine precursor is obtained by polycondensing a diamine with an acid dianhydride. Further, the polyimide resin forming the insulating coating layer 20 is obtained by imidating a molded article formed of a polyimide pigment precursor varnish.

The diamine component of the polyimine precursor is at least 20 mol% or more and 56 mol% or less of the diamine component A represented by the chemical formula (1) with respect to the total amount of the diamine, and relative to the diamine The diamine component B represented by the chemical formula (2) in which the total amount is 44 mol% or more and 80 mol% or less is a constituent component. In addition, the acid dianhydride of the polyimine precursor is at least 60 mol% or more and 100 mol% or less of the acid dianhydride component C represented by the chemical formula (3) with respect to the total amount of the acid dianhydride. The acid dianhydride component D represented by the chemical formula (4) with respect to the total amount of the acid dianhydride is 0 mol% or more, and 40 mol% or less is a structural component. The lower limit of the pyromellitic dianhydride represented by the chemical formula (3) is more preferably 70 mol% or more, and still more preferably 80 mol% or more. Further, the upper limit of the acid dianhydride component D represented by the chemical formula (4) is more preferably 30 mol% or less, further preferably 20 mol% or less.

(wherein X represents a single bond, an oxygen atom, a sulfur atom, a thiol group, a carbonyl group, a methylene group, an isopropylidene group or a divalent isopropyl group of hexafluoroisopropylidene)

(wherein Y represents a single bond, an oxygen atom, a sulfur atom, a thiol group, a carbonyl group, a methylene group, an isopropylidene group or a divalent group of a hexafluoroisopropylidene group)

In the case of synthesizing a polyimine precursor, the above chemical formula (1), chemical formula (2), and chemical formula (4) may independently use a single species or a plurality of compounds.

Preferable examples of the diamine component B of the chemical formula (2) include bis[4-(3-aminophenoxy)phenyl] sulfide and bis[4-(3-aminophenoxy)phenyl.碸, bis[4-(3-aminophenoxy)phenyl]one, 4,4'-bis(3-aminophenoxy)biphenyl, 4,4'-bis(4-amino Phenoxy)biphenyl, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]- 1,1,1,3,3,3-hexafluoropropane, and the like.

A particularly preferable example of the diamine component B is 4,4'-bis(3-aminophenoxy)biphenyl described in the chemical formula (5).

Preferable examples of the diamine component A of the chemical formula (1) include 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, and 3,3'-diaminodiphenyl ether. Wait. From the viewpoint of improving crystallinity, 4,4'-diaminodiphenyl ether represented by the chemical formula (6) is particularly preferred.

The diamine preferably has a diamine component A of 20 mol% to 56 mol% relative to the total amount of the diamine, and a diamine component B of 44 mol% to 80 with respect to the total amount of the diamine. Moer%. By setting it as this range, it is more effective to combine both low water absorption and high Tg. The lower limit of the diamine component A is further preferably 24 mol% based on the total amount of the diamine. The above is particularly preferably 30 mol% or more, and particularly preferably 39 mol% or more. Further, the upper limit of the total amount of the diamine component A based on the total amount of the diamine is preferably 51% by mole or less, and more preferably 50% by mole or less. More preferably, the diamine component B is 49 mol% or more based on the total amount of the diamine, and the upper limit is more preferably 76 mol% or less, particularly preferably 70 mol% or less, and most preferably 61. Mole% or less.

The diamine in the present embodiment may also use a diamine other than the chemical formula (1) or the chemical formula (2) within the range not departing from the gist of the invention. From the viewpoint of heat resistance, the other diamine is preferably an aromatic diamine.

Examples of the other aromatic diamines include p-phenylenediamine, m-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, 4,4'-diaminobiphenyl, and 3,3'-diamino group. Biphenyl, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 1,1-bis(4-aminophenyl)ethane, 1,1-double (3-Aminophenyl)ethane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)propane, 2,2-bis(4-amine Phenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-bis-(3-aminophenyl)-1,1,1,3,3,3-hexafluoro Propane, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenylanthracene, 3,3'-diamine Diphenyl ketone, 4,4'-diaminodiphenyl ketone, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene , 2,2'-bis(4-(4-aminophenoxy)phenyl)propane, 2,2'-dimethyl-4,4'-diaminobiphenyl, bis(aminophenyl) Bis (amino acid fluorene), bis-methylaminoaniline, 2,7-diaminopurine, 2,2'-bis(trifluoromethyl)-1,1'-biphenyl-4,4'-diamine 4,4'-methylenediphenylamine, 4,4'-(m-phenylenediisopropylidene)dianiline (4,4'-(m-phenylenediisopropylidene)dianiline).

Preferable examples of the acid dianhydride component D represented by the above chemical formula (4) include 3,3',4,4'-biphenyltetracarboxylic dianhydride and 2,2',3,3'-biphenyl. Tetracarboxylic dianhydride, 3,3',4,4'-diphenyl ketone tetracarboxylic dianhydride, 2,2',3,3'-diphenyl ketone tetracarboxylic dianhydride, 2,2- Double (3,4- Dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, bis(2,3-di Carboxyphenyl)ether dianhydride, bis(3,4-dicarboxyphenyl)ruthenic anhydride, bis(2,3-dicarboxyphenyl)ruthenium anhydride, 2,2-bis(3,4-dicarboxyl) Phenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3- Hexachloropropane dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxybenzene) A compound such as methane dianhydride, 4,4'-(p-phenylenedioxy)diphthalic dianhydride or 4,4'-(m-phenylenedioxy)diphthalic dianhydride.

Among these, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenyl ketone tetracarboxylic dianhydride, 3,3' are more preferred. 4,4'-diphenyl ether tetracarboxylic dianhydride, p-phenylenedioxybis(4-phthalic acid) dianhydride.

Particularly preferred is 3,3',4,4'-biphenyltetracarboxylic dianhydride described in Chemical Formula (7).

The acid dianhydride component C may be used alone as the acid dianhydride, and the acid dianhydride component D may be added in addition to the acid dianhydride component C. As the acid dianhydride component D, one type of compound may be used, or two or more types of compounds may be used in combination. Further, an acid dianhydride component having another structure may be added in addition to the acid dianhydride component C and the acid dianhydride component D.

The acid dianhydride in the present embodiment may contain other acid dianhydrides in addition to the above-described specific amounts of the above chemical formula (3) and chemical formula (4). From the viewpoint of heat resistance, the other acid dianhydride is preferably an aromatic acid dianhydride.

Other aromatic acid dianhydrides are, for example, 1,2,3,4-benzenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid Acid dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid Anhydride, 3,4,9,10-decanetetracarboxylic dianhydride, 2,3,6,7-nonanetetracarboxylic dianhydride, 1,2,7,8-phenanthrenetetracarboxylic dianhydride, and the like.

The insulating film obtained from the polyimine precursor varnish of the above structure can provide a raw material having excellent insulating properties and mechanical strength, and further having heat resistance and low water absorption.

The polyimine precursor varnish used for the insulating coating layer of the electric wire of the electric wire of the present invention is coated with a polyimide varnish as a composition, and is heated at 5 ° C / min. The polyimine film (hereinafter, simply referred to as "polyimine film") having a coating film thickness of 20 μm or more and 60 μm or less after drying at 300 ° C in a nitrogen atmosphere for 1 hour is preferably used. All of the following conditions are satisfied: (i) the glass transition temperature is 290 ° C or higher; (ii) the water absorption ratio is 2.0% or less; and (iii) the tensile elongation at break is 55% or more.

In order to make the thickness of the coating film after drying the polyimide film of 20 μm to 60 μm, for example, the coating film of the polyimide precursor varnish may be formed to have a thickness of 300 μm to 400 μm. The method for producing the above polyimide film is not particularly limited, and the following methods are exemplified. That is, using a applicator having a gap of 300 μm to 400 μm, a polyimine precursor varnish is applied to a glass plate using a tabletop coater; then, an explosion-proof dryer is used immediately, as above The temperature was raised from normal temperature at 5 ° C/min in a nitrogen atmosphere, and maintained at 300 ° C for 1 hour. Thereafter, after sufficiently cooling by natural cooling, it was immersed in warm water for 24 hours, thereby concentrating the polyfluorene. The imine film is peeled off from the glass plate; then, the polyimide film is sufficiently dried to prepare a film thickness after drying to a thickness of 20 μm to 60 μm.

Further, the polyimide varnish precursor of the present invention preferably satisfies the characteristics of the above (i) to (iii) when the film thickness of the polyimide film is produced, but The film thickness of the utilization form of the polyimide varnish varnish precursor of the present invention is not specified.

The glass transition temperature of (i) in the above polyimide film is more preferably 295 ° C or higher, and still more preferably 300 ° C or higher, from the viewpoint of providing a more excellent raw material. Further, the water absorption rate of (ii) is more preferably 1.9% or less, further preferably 1.8% or less. Further, the tensile elongation at break of (iii) is more preferably 70% or more, and particularly preferably 100% or more. Further, from the viewpoint of improving the partial discharge voltage resistance of the insulator, the dielectric constant of the polyimide resin at a measurement frequency of 1 Hz is preferably 3.6 or less, more preferably 3.5 or less, still more preferably 3.4 or less. .

In the present specification, the glass transition temperature means a value measured by the following method. Specifically, the temperature dispersion measurement of the solid viscoelasticity of the above polyimide film was carried out using a RSA-II manufactured by TA Instruments (TA Instruments) under the conditions of a tensile mode and a measurement frequency of 1 Hz, and the storage elastic modulus E' was measured. And the loss elastic modulus E". Then, the value of the "glass transition temperature" is derived from the peak of the obtained loss tangent tan δ = E" / E'.

Further, the water absorption rate in the present specification means a value measured by the following method. Namely, the above polyimide film was cut into a size of 50 mm × 50 mm, and dried at 150 ° C for 5 minutes, and then the mass was measured. Thereafter, it was immersed in ion-exchanged water at 23 ° C for 24 hours. After the immersion, the water adhering to the surface of the sample taken out from the water tank is sufficiently scattered by an air gun or the like, and then the mass is measured, and the value of the water absorption rate is calculated according to the following formula (1).

<Number 1> Water absorption rate = {(mass of sample after immersion) - (sample quality before immersion)} ÷ (sample quality before immersion)... Equation (1)

Further, the tensile elongation at break means a value measured by the following method. In other words, the polyimine film was cut into a size of 140 mm × 10 mm in width, and the actual measurement length was set to 100 mm (wherein 20 mm portions at both ends were stretched regions), and AUTOGRAPH AGS-100D manufactured by Shimadzu Corporation was used. A short strip of film sample was drawn at a speed of 50 mm/min at room temperature (23 ° C). The value calculated from (the length of the polyimide film at the time of the fracture) / (the length of the original polyimide film) at this time was taken as the tensile elongation at break.

The number average molecular weight of the polyimine precursor of the present embodiment is not particularly limited, and may be, for example, in the range of 5,000 to 1,000,000. A preferred range is from 5,000 to 50,000. The number average molecular weight of the polyimine precursor can be measured by gel permeation chromatography (GPC, Gel Permeation Chromatography).

Next, a method of producing a polyimide precursor varnish will be described. First, the specific diamine described above is reacted with a specific tetracarboxylic dianhydride to obtain a poly-proline. The ratio of the acid dianhydride of the polyimine precursor to the synthesis of the diamine is not particularly limited, and it is preferably the total of the diamine component A and the diamine component B with respect to the total of the diamine and the acid dianhydride. The total amount is 47.5 mol% to 52.5 mol%, and the total of the acid dianhydride component C and the acid dianhydride component D satisfies the range of 47.5 mol% to 52.5 mol%.

The polymerization can also be carried out in a solid phase system, but is preferably carried out in a liquid phase system. In the liquid phase system, the polymerization concentration is, for example, about 20% by mass to 30% by mass. The reaction solvent is not particularly limited, and is preferably a solvent having a boiling point of 100 ° C or higher. A solvent generally used in the polymerization of a polyimide intermediate can be preferably used. For example, at least one of the reaction materials may be dissolved, and a solvent which can dissolve both the acid dianhydride and the diamine is preferred. Specific examples thereof include N,N-dimethylformamide, N,N-dimethylacetamide, cresol, dimethyl hydrazine, and N-methyl-2-pyrrolidone. Tetramethylurea (tetramethylurea) and the like. These solvents may be used singly or in combination with other solvents such as benzonitrile, dioxane, xylene or toluene.

The production of the polyimide precursor can be carried out without using a catalyst, and a catalyst can also be suitably used. The catalyst is not particularly limited insofar as it does not depart from the gist of the invention. In addition, the amount of the catalyst to be used may be appropriately adjusted in consideration of the properties of the catalyst itself such as the dispersibility of the catalyst or the acid strength, and the reaction conditions.

In the liquid phase reaction step, the order of addition and the addition method of the raw material, the solvent, and other catalysts to be added as needed are not particularly limited. The reaction temperature is not particularly limited as long as the desired number average molecular weight (Mn) can be obtained. When the polymeric polyamine is used as the polyimide precursor, the reaction temperature is usually 20° C. or higher and 100° C. or lower. The reaction time is not limited as long as it is sufficient for obtaining a desired degree of polymerization. Further, in the reaction, it is preferred to carry out the reaction in an inert gas atmosphere such as nitrogen. The solid content concentration in the reaction system (in the reactor) is not particularly limited, but is usually 5% by mass or more and 50% by mass or less.

The reaction apparatus is not particularly limited, and examples thereof include a super blend (manufactured by Sumitomo Heavy Industries, Ltd.), an aichih chemical mixer (manufactured by Aijo Co., Ltd.), and a planetary mixer (planetary). Mixer, such as mixer (manufactured by Inoue Co., Ltd.) and Trimix (manufactured by Inoue Co., Ltd.).

The polyimine precursor varnish contains at least a polyimide precursor and a solvent as described above. The concentration of the solid content of the resin in the polyimide varnish is preferably from 5% by mass to 50% by mass, and more preferably from 10% by mass to 30% by mass, from the viewpoint of improving the coating property. The solvent is not particularly limited, and is preferably a polar solvent. pole Examples of the solvent include N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylformamide, N,N-diethylacetamide, N , N-dimethyl methoxy acetamide, dimethyl hydrazine, hexamethyl phosphoramide, N-methyl-2-pyrrolidone, dimethyl hydrazine, etc., in addition to Two or more mixed solvents of the solvents, or the solvents and benzene, toluene, xylene, benzonitrile, dioxane, cyclohexane, 1,3,5-trimethylbenzene as a nonpolar solvent A mixed solvent of 1,2,4-trimethylbenzene or the like.

Inorganic fine particles such as silica, alumina, or titanium oxide may also be dispersed in the polyimine precursor varnish of the present invention. Further, the polyamidene precursor varnish of the present invention may contain any additives insofar as it does not deviate from the gist of the present invention. For example, a bonding aid, an adhesive, an antioxidant, a UV absorber, a colorant, or the like may be added. For example, a surface modifier such as a decane coupling agent may be added. Preferred additives are exemplified by epoxy, bismaleimide, and nadiimide. From the viewpoint of heat resistance and reactivity, it is preferred to add bismaleimide having a molecular weight of 600 or less. The polyimine precursor of the present invention may be used in a single type or in combination of a plurality of types. Further, the polyimine resin of the present invention may be mixed with a polymer different from the polyimine resin of the present invention within a range not departing from the gist of the present invention. Further, the polyamidene precursor varnish may also comprise a partially quinone imidized precursor.

In the prior polyimine resin, the water absorption rate usually caused by the quinone imine group exceeded 2.0%. Therefore, for example, when a polyimide coating is used as the insulating coating layer of the conductor of the insulated electric wire, there is a problem that the transmission loss increases due to the insulating coating layer. Further, the conventional polyimide resin has a problem that it is liable to cause poor insulation due to water absorption under high heat of humidity.

By using the polyimine structure of Patent Document 1 as described above, the water absorption rate can be improved by relatively lowering the density of the quinone imine group. However, since the glass transition temperature is lowered, there is a problem in heat resistance. Thus, the low water absorption property and the heat resistance of the polyimide resin are in a trade-off relationship, and it is difficult to satisfy both low water absorption and heat resistance. Further, when molding is performed by a melt extrusion molding method as in Patent Document 1, it is usually necessary to perform molding at a high temperature of 400 ° C or higher, which is close to the thermal decomposition temperature of the resin. Therefore, it is necessary to precisely control the molding conditions.

The polyamidene precursor varnish according to the present invention, by introducing a specific ratio of pyromellitic dianhydride of the formula (3), or a specific ratio of pyromellitic dianhydride and the chemical formula (4) as an acid dianhydride, Further, when the diamine of the chemical formula (1) or the chemical formula (2) is used, the rigidity of the ruthenium imine group can be reduced and the crystallinity can be improved when the polyimide resin is produced. As a result, it was considered that the balance between low water absorption and high glass transition temperature, high mechanical strength, and insulating properties was successfully obtained. Moreover, the obtained polyimide resin has an advantage of achieving low dielectric constant.

Further, in the above polyimide film, the glass transition temperature is 290 ° C or higher, the water absorption ratio is 2.0% or less, and the tensile elongation at break is 55% or more, thereby providing a combination of low water absorption and high glass. A polyimide resin having excellent balance of transfer temperature and high mechanical strength. More specifically, by setting the glass transition temperature to 290 ° C or higher, excellent reliability and durability can be achieved even in a high temperature environment. For example, it can be used for a long time even in an environment of about 250 °C. Moreover, when the water absorption ratio is 2.0% or less, the transmission loss can be reduced when used as an insulating coating layer of a coated square conductor. Further, by setting the tensile elongation at break to 55% or more, excellent mechanical strength can be achieved, and excellent reliability and durability can be achieved. Moreover, when the tensile elongation at break is 55% or more, flexibility is also excellent. Polyimide tree The grease has excellent chemical resistance properties. Therefore, there is an advantage that it can be used even under severe conditions such as high temperature and humidity, or in applications requiring chemical resistance. Moreover, the method of coating a polythenimine precursor varnish according to the present invention has the advantage of being heat-dryable at 400 ° C or lower and being easily thinned.

Further, when a polybendimimine skeleton is introduced, 4,4'-bis(3-aminophenoxy)biphenyl (hereinafter referred to as m-BP) and 3,3',4,4'-linked A structure mainly composed of a biphenyl structure such as benzenetetracarboxylic dianhydride (hereinafter referred to as s-BPDA) can further reduce the density of the sulfimine group and improve the crystallinity, and further realize the effect. Straightening produced by the introduction of 4,4'-diaminodiphenyl ether and pyromellitic dianhydride. Therefore, the balance between low water absorption, high glass transition temperature, and high mechanical strength can be obtained more effectively.

Next, an example of a method of manufacturing the rectangular electric wire of the present invention will be described. However, the present invention is not limited to the following production methods, and the present invention can be produced by various production methods.

First, a linear square conductor 10 is prepared. Then, the polyimide film precursor varnish is coated on the square conductor 10, dried, and baked. The coating method is not particularly limited, and a method of directly applying the outer circumference of the square conductor 10 can be exemplified. By polypyrene, the polyimine precursor is converted to polyimine. When the thickness of the insulating coating layer 20 is to be thick, a plurality of coating and baking steps can be performed. Further, after forming an adhesion layer or a protective layer on the square conductor 10, the polyimide film precursor varnish may be applied to the upper layer of the adhesion layer or the protective layer, dried, and baked. When the insulating coating layer other than the polyimine resin layer is laminated, a known formation method can be suitably used.

The baking step is not particularly limited, and it is preferably carried out in an inert gas, for example, under a nitrogen atmosphere. The heating condition is not particularly limited as long as it can be converted from a polyimine precursor to a polyimine, and is, for example, 200 ° C. The heating process is carried out at a temperature of about 400 ° C in the range of 1 minute to 10 hours.

Fig. 2 is a schematic view showing an example of a winding coil for explaining the present invention. The winding coil 5 is configured such that a square wire 1 is wound around a core of a core 30 containing a magnetic material. The core body 30 also includes a lead portion, an electrode, and the like of the square electric wire 1 (not shown). The winding coil 5 can be used, for example, as a rotor or a stator of an electric motor. The number of turns of the rectangular wire 1 of the winding coil 5 and the like are appropriately designed in accordance with electrical characteristics required for the motor and the like. The generated electromagnetic force can be efficiently flowed by the current flowing in the winding coil of the rotor.

According to the square electric wire of the present invention, since the polyimine resin obtained from the polyimide precursor varnish of the present invention is used in at least one layer of the insulating coating layer 20, the mechanical strength is excellent, and even if a strong external force is applied, The inner square conductor 10 is appropriately protected. Moreover, the square electric wire according to the present invention is excellent in mechanical strength and excellent in flexibility, and therefore has an advantage that winding is easy. Moreover, since the polyimine resin of the present invention is excellent in low water absorbability, the transmission loss of the square electric wire 1 can be reduced. Further, since the polyimide resin of the present invention is excellent in moisture resistance and heat resistance, it can be preferably used under severe conditions such as high temperature and high humidity.

Further, according to the square electric wire of the present invention, by forming the cross-sectional shape into a square shape, the space factor at the time of forming the winding coil can be improved. By increasing the duty factor, when the power is set to the same power, the core body can be reduced to achieve miniaturization and weight reduction. Moreover, when the same core body is used, the number of windings can be increased to achieve high power. Further, by forming the cross-sectional shape into a square shape, heat dissipation can be expected to be improved. Further, the polyimine resin obtained from the polyamidene precursor varnish of the present invention is composed of Since the dielectric constant is low, it has an excellent property of maintaining good insulating properties even when the square wires are in close contact with each other.

≪Example≫

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited by the following examples.

[Example 1] (Preparation of polyimine precursor varnish) 4,4'-diaminodiphenyl ether (manufactured by Wakayama Seiki Co., Ltd.) (hereinafter referred to as "4, 4'-ODA"), 4,4'-bis(3-aminophenoxy)biphenyl (manufactured by Mitsui Chemicals, Inc.) (hereinafter, referred to as "m-BP"), two kinds of diamines and pyromellitic dianhydride (Mitsubishi Gas Chemicals) The acid dianhydride (hereinafter referred to as "PMDA") was formulated in a dimethylacetamide solvent at a molar ratio of 4,4'-ODA:m-BP:PMDA=20:30:49.5. Then, the mixture was stirred for 4 hours or more to obtain a polyimide varnish varnish having a resin solid content ratio of 20% by mass to 25% by mass.

(Production of Polyimine Film) The above polyimide film precursor varnish was applied onto a glass plate using a table top coater using an applicator having a gap of 360 μm. Immediately after coating, it was dried in a nitrogen atmosphere using an explosion-proof dryer. The drying was started from normal temperature at 5 ° C / min, and kept at 300 ° C for 1 hour. Thereafter, it is naturally cooled. After sufficiently cooling, it was immersed in warm water for 24 hours, whereby the polyimide film was peeled off from the glass plate to obtain a desired polyimide film sample. The film thickness of the obtained polyimide film after drying was 30 μm.

(Evaluation of Water Absorption) The water absorption of the film sample produced was evaluated based on the water absorption rate. The sample of the object was cut into a size of 50 mm × 50 mm, and dried at 150 ° C for 5 minutes, and the mass was measured immediately. Thereafter, it was immersed in ion-exchanged water at 23 ° C for 24 hours. After immersion, the surface of the sample taken out of the water tank is attached by an air gun. The water was sufficiently scattered, and the mass was measured thereafter, and the water absorption rate was calculated from the above formula (1). The sample having a water absorption of 2.0% or less was evaluated as ○, and the sample having a water absorption of more than 2.0% was evaluated as ×.

(Evaluation of Glass Transition Temperature (Evaluation of Heat Resistance)) The glass transition temperature of the polyimide film produced by the above method was evaluated. The measurement was carried out in such a manner that the storage elastic modulus E′ and the loss elastic modulus E′′ were evaluated by the temperature dispersion measurement (stretching mode) of the solid viscoelasticity, and the loss tangent tan δ=E”/E′ Peak derived glass transition temperature. The measuring device was an RSA-III manufactured by TA Instruments. The polyimide film having a glass transition temperature of 290 ° C or higher was evaluated as ○, and the polyimide film having a glass transition temperature of less than 290 ° C was evaluated as ×.

(Mechanical strength evaluation) The tensile mechanical strength of the produced polyimide film was measured. The sample was cut into a size of 140 mm × width 10 mm, and a 20 mm portion at both ends was used as a stretching region (actual measurement length was 100 mm). The tensile elongation at break (also referred to simply as "elongation at break") was measured by stretching a film sample of a short strip at a speed of 50 mm/min. The measuring device was an AUTOGRAPH AGS-100D manufactured by Shimadzu Corporation. The polyimide film having an elongation at break of 55% or more was evaluated as ○, and the polyimide film having less than 55% was evaluated as ×.

(Evaluation of Dielectric Constant) The dielectric constant was evaluated by the method according to JIS K6911 on the polyimide film produced by the above method. Using the LCR meter HP4284A manufactured by Agilent Technologies, at 1MHz, main electrode = 18mm , guard electrode (26mm) , opposite electrode = 28mm The polyimide film sample after leaving it at 22 ° C × 60% RH for 24 hours was evaluated in an environment of 22 ° C × 60% RH.

[Example 2] Divided by 4,4'-ODA:m-BP:PMDA=25:25:49.5 molar ratio formulated as diamine 4,4'-ODA, m-BP and as acid II A polyimide pigment precursor varnish was produced and evaluated in the same manner as in Example 1 except for PMDA of an anhydride. The film thickness was adjusted to 30 μm (the same applies to the following examples and comparative examples, and was adjusted to 30 μm in the same manner).

[Example 3] Divided by 4,4'-ODA:m-BP:PMDA=12.5:37.5:49.5 molar ratio of 4,4'-ODA, m-BP as a diamine and as an acid A polyimide pigment precursor varnish was produced and evaluated in the same manner as in Example 1 except for PMDA of an anhydride.

[Example 4] In addition to 4,4'-ODA, m-BP as a diamine and PMDA, 3,3',4,4'-biphenyltetracarboxylic dianhydride as an acid dianhydride (Jie JFE Chemical (manufactured by JFE Chemical Co., Ltd.) (hereinafter referred to as "s-BPDA") two types of M4 with 4,4'-ODA:m-BP:PMDA:s-BPDA=25:25:44.55:4.95 A polyimide pigment precursor varnish was produced and evaluated in the same manner as in Example 1 except that the blending was carried out.

[Example 5] Divided by 4,4'-ODA:m-BP:PMDA:s-BPDA=25:25:35:14.5 molar ratio formulated as a diamine 4,4'-ODA, m-BP A polyimide polyimide precursor varnish was produced and evaluated in the same manner as in Example 1 except for the two types of PMDA and s-BPDA which are acid dianhydride.

[Example 6] In addition to 4,4'-ODA, m-BP, and 1,3-bis(4-aminophenoxy)benzene as a diamine (manufactured by Nippon Pure Chemical Co., Ltd., hereinafter referred to as 4-APB) Three kinds of PMDA and s-BPDA as acid dianhydride were carried out with 4:4'-ODA:m-BP:4-APB:PMDA:s-BPDA=10:25:15:35:14.5 molar ratio. A polyimide quinone precursor varnish was produced and evaluated in the same manner as in Example 1 except for the preparation.

[Comparative Example 1] The same procedure as in Example 1 except that 4,4'-ODA of 4,4'-ODA:PMDA=50:49.5 was used as the 4,4'-ODA of the diamine and PMDA as the acid dianhydride. The polyimine precursor varnish was produced in the manner and evaluated.

[Comparative Example 2] Polyimine was produced in the same manner as in Example 1 except that m-BP having m-BP:PMDA = 50:49.5 was blended as m-BP of diamine or PMDA as acid dianhydride. The precursor varnish was evaluated.

[Comparative Example 3] Divided by 4,4'-ODA:m-BP:PMDA:s-BPDA=25:25:24.5:25 molar ratio formulated as a diamine 4,4'-ODA, m-BP A polyimide polyimide precursor varnish was produced and evaluated in the same manner as in Example 1 except for the two types of PMDA and s-BPDA which are acid dianhydride.

[Comparative Example 4] In addition to 4,4'-(m-phenylene isopropylidene)diphenylamine (manufactured by Mitsui Fine Chemicals Co., Ltd.) as a diamine (hereinafter referred to as "diphenylamine M"), A polyimine precursor was produced in the same manner as in Example 1 except that m-BP was blended with PMDA as an acid dianhydride in a molar ratio of dianiline M:m-BP:PMDA=25:25:49.5. The varnish was varnished and evaluated.

[Comparative Example 5] In addition to 2,2'-dimethyl-4,4'-diaminobiphenyl (manufactured by Wakayama Seiki Co., Ltd.) (hereinafter referred to as "m-tolidine"), Poly-imine was produced in the same manner as in Example 1 except that m-BP was blended with PMDA as an acid dianhydride in a molar ratio of m-toluidine:m-BP:PMDA=25:25:49.5. The precursor varnish was evaluated.

[Comparative Example 6] Divided by 4,4'-ODA:m-BP:PMDA=7.5:42.5:49.5 molar ratio of 4,4'-ODA, m-BP as a diamine and as an acid A polyimine precursor varnish was produced and evaluated in the same manner as in Example 1 except for one of PMDA of an anhydride.

The preparation ratio of the polyamido acid varnish is shown in Table 1, and the results of the physical property values are shown in Table 2.

It was confirmed that the polyimide film of the present example is excellent in low dielectric constant. For example, the dielectric constant of the polyimine film of Comparative Example 1 is 3.61, the dielectric constant of the polyimide film of Example 2 is 3.35, and the dielectric constant of the polyimide film of Example 5 is 3.33.

According to the present embodiment, it is understood that the glass transition temperature is 290 ° C or higher, the water absorption ratio is 2.0% or less, and the tensile elongation at break is 55% or more, excellent in mechanical strength, and heat resistance in any of the polyimide films. Both low water absorption provide the necessary and sufficient characteristics.

[Industrial availability]

The present invention can provide an insulating coating layer having excellent insulating properties and mechanical strength, thereby satisfying both heat resistance and low water absorption, and is therefore particularly suitable for vehicles used under severe conditions such as high temperature environment and high humidity environment. The ship's motor winding wire is a square wire, but it can also be widely used for motor winding applications other than vehicle ships. Moreover, it is not limited to the use of the motor winding, and can be widely applied to various insulated electric wires and insulating coating layers.

1‧‧‧ square wire

10‧‧‧ square conductor

20‧‧‧Insulation coating

Claims (8)

A square electric wire for a motor winding of a vehicle ship, comprising: a square conductor; and an insulating coating layer covering the square conductor, at least a part of the insulating coating layer being a polyimide resin, and the polyimine resin is Obtained by imidating a shaped article formed of a polyimine precursor varnish comprising a composition comprising a polyimide precursor and a solvent, the polyimine precursor being obtained by reacting a diamine with And the diamine component A represented by the chemical formula (1) at least 20 mol% or more and 56 mol% or less based on the total amount of the diamine, and the diamine The diamine component B represented by the chemical formula (2) in which the total amount of the diamine is 44 mol% or more and 80 mol% or less is a constituent component; and the acid dianhydride is at least the total amount of the acid dianhydride. 60 g% or more and 100 mol% or less of the acid dianhydride component C represented by the chemical formula (3) and a chemical formula of 0 mol% or more and 40 mol% or less based on the total amount of the acid dianhydride ( 4) The acid dianhydride component D represented is a constituent component; (wherein X represents a single bond, an oxygen atom, a sulfur atom, a thiol group, a carbonyl group, a methylene group, an isopropylidene group or a divalent isopropyl group of hexafluoroisopropylidene) (wherein Y represents a single bond, an oxygen atom, a sulfur atom, a thiol group, a carbonyl group, a methylene group, an isopropylidene group or a divalent group of a hexafluoroisopropylidene group). The square wire for electric motor winding of a vehicle ship according to claim 1, wherein the composition is applied to a film, heated at 5 ° C / min, and heated at 300 ° C for 1 hour in a nitrogen atmosphere. The obtained polyimide film having a thickness of 20 μm to 60 μm after drying has a glass transition temperature of 290 ° C or higher, a water absorption ratio of 2.0% or less, and a tensile elongation at break of 55% or more. The square wire for electric motor winding of a vehicle according to claim 1 or 2, wherein the polyimine precursor is a total of the diamine relative to the diamine and the acid dianhydride. The total of the component A and the diamine component B satisfies 47.5 mol% to 52.5 mol%, and the total of the acid dianhydride component C and the acid dianhydride component D satisfies the range of 47.5 mol% to 52.5 mol%. Copolymerized. The square wire for electric motor winding of a vehicle according to claim 1 or 2, wherein the diamine component B is 4,4'-bis(3-aminobenzene) represented by the chemical formula (5). Oxy)biphenyl: The square wire for electric motor winding of a vehicle according to claim 1 or 2, wherein the diamine component A is 4,4'-diaminodiphenyl ether of the formula (6): The square wire for electric motor winding of a vehicle according to claim 1 or 2, wherein the acid dianhydride component D is 3, 3', 4, 4'-linked according to the chemical formula (7). Pyromellitic dianhydride: A winding coil is obtained by winding a square wire for a motor winding wire of a vehicle according to any one of the first to sixth aspects of the invention. An electric motor comprising the winding coil as described in claim 7 of the patent application.