JP2010215757A - Insulating film for electromagnetic coil, and motor and transformer equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve flame retardancy, moldability and water resistance of an insulating film for electromagnetic coils used in motors and transformers. <P>SOLUTION: The insulating film for electromagnetic coils is constituted of a liquid crystal polyester. The liquid crystal polyester is soluble in solvents and has a flow-starting temperature of ≥250°C. The insulating film having excellent flame retardancy, moldability and water resistance and used for electromagnetic coils for motors and transformers is obtained by using the liquid crystal polyester. The practical durability of motors and transformers is enhanced by fabricating the motors and transformers by using the insulating film for electromagnetic coils. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electromagnetic coil insulating film applied to an electrical component that requires safety when an abnormal voltage occurs, such as a motor (electric motor) or a transformer (transformer), and a motor and a transformer using the electromagnetic coil insulating film. It is about.

  Conventionally, in a motor, an insulating film is formed in the shape of a slot or a wedge and inserted between the coils in order to electrically insulate a plurality of coils (electromagnetic coils) from each other. In addition, in the transformer, an insulating film is used as an interlayer insulating material or a spacer in the coil winding for the same purpose as the motor. And as these insulating films, the film which consists of polyesters, such as a polyethylene terephthalate, ie, a polyester film, is widely used from the point which is excellent in electrical insulation and moldability.

  However, since this polyester film is generally inferior in flame retardancy, there is a disadvantage that it easily burns when heat generation energy is generated due to an overcurrent generated in a motor or transformer coil.

  Therefore, in order to improve the flame retardancy of the polyester film and make up for the above-mentioned drawbacks, a technique of incorporating a brominated, phosphorous or inorganic flame retardant into the polyester film, or a polyester containing a halogen-containing component or a phosphorus-containing component is used. Techniques for polymerization have been proposed (see, for example, Patent Documents 1 and 2).

Japanese Patent Laid-Open No. 10-278206 JP 2002-172747 A

  However, the technique for improving the flame retardancy of the polyester film proposed in Patent Documents 1 and 2 is based on the addition of a flame retardant and the copolymerization of a halogen-containing component and a phosphorus-containing component. There was a problem that the original mechanical properties and moldability were deteriorated.

  In addition to such flame retardancy, in recent years, in order to increase the practical durability of motors and transformers, electrical insulation materials for motors and transformers are required to have heat resistance and water resistance (low moisture absorption). It has become to. For example, electrical insulation materials for motors used in refrigerators and air conditioners are required to have enough heat resistance to withstand the heat generated when the motor is used. Various chlorofluorocarbon alternative refrigerants have been proposed one after another, but water resistance is required because these refrigerants and the corresponding lubricating oils easily adsorb moisture. In addition, electrical insulation materials for motors used in hybrid and electric vehicles are required to have sufficient heat resistance to withstand the heat generated during the use of this motor, and water can penetrate under the usage environment. Is required.

  However, when the polyester film is, for example, a film made of polyethylene terephthalate, the water absorption is about 0.56% by mass, and it has been desired to further reduce the water absorption.

  Therefore, in view of such circumstances, a first object of the present invention is to provide an electromagnetic coil insulating film that is excellent in flame retardancy, molding processability, and water resistance, and is useful for insulating an electromagnetic coil of a motor or a transformer. Furthermore, a second object is to provide a motor and a transformer capable of enhancing practical durability by using the electromagnetic coil insulating film.

  In order to achieve this object, the present inventor has focused on adopting liquid crystal polyester as a raw material for the electromagnetic coil insulating film.

  That is, the invention described in claim 1 is characterized in that the electromagnetic coil insulating film is made of liquid crystal polyester.

  The invention described in claim 2 is characterized in that, in addition to the structure described in claim 1, the liquid crystal polyester has solvent solubility.

  The invention described in claim 3 is characterized in that, in addition to the structure described in claim 1 or 2, the liquid crystalline polyester has a flow start temperature of 250 ° C. or higher.

Moreover, in addition to the structure in any one of Claims 1 thru | or 3, the invention of Claim 4 WHEREIN: The said liquid crystalline polyester is a structural unit shown by the following formula | equation (1), (2) and (3). The structural unit represented by the formula (1) is 30.0 to 60.0 mol% and the structural unit represented by the formula (2) is 20.0 to 35.0 based on the total of all the structural units. The liquid crystal polyester is characterized in that the structural unit represented by mol% and the formula (3) is 20.0 to 35.0 mol%.
⁽¹⁾ -O-Ar 1 -CO-
(2) —CO—Ar ² —CO—
⁽³⁾ -X-Ar 3 -Y-
(In the formula, Ar ¹ represents phenylene or naphthylene, Ar ² represents phenylene, naphthylene, or a group represented by the following formula (4), and Ar ³ represents a group represented by phenylene or the following formula (4). And X and Y each independently represent O or NH, wherein the hydrogen atom bonded to the aromatic ring of Ar ¹ , Ar ² and Ar ³ is substituted with an alkyl group or an aryl group. May be good.)
^{(4) -Ar 11 -Z-Ar} 12 -
(In the formula, Ar ¹¹ and Ar ¹² each independently represent phenylene or naphthylene, and Z represents O, CO, or SO _2. )

  The invention described in claim 5 is characterized in that, in addition to the structure described in claim 4, at least one of X and Y of the structural unit represented by the formula (3) is NH.

  Moreover, in addition to the structure in any one of Claims 1 thru | or 3, the invention of Claim 6 WHEREIN: The said liquid crystalline polyester is a structural unit derived from p-hydroxybenzoic acid, and 2-hydroxy-6-naphthoic acid. The total number of structural units derived from 30.0 to 60.0 mol%, the structural unit derived from terephthalic acid, the structural unit derived from isophthalic acid, and the total of structural units derived from 2,6-naphthalenedicarboxylic acid is 20 A liquid crystalline polyester having a structural unit derived from 0.0 to 35.0 mol% and derived from 4-aminophenol is 20.0 to 35.0 mol%.

  The invention described in claim 7 is a motor using the electromagnetic coil insulating film.

  Furthermore, the invention described in claim 8 is characterized in that it is a transformer in which the electromagnetic coil insulating film is used.

  According to the present invention, since the raw material of the electromagnetic coil insulating film is a specific liquid crystal polyester, it is possible to provide an electromagnetic coil insulating film for a motor or transformer excellent in flame retardancy, molding processability, and water resistance. it can. Therefore, by assembling a motor or a transformer using this electromagnetic coil insulating film, it is possible to increase the practical durability of these electrical components.

It is a half sectional view showing a motor in which an electromagnetic coil insulating film according to Embodiment 1 of the present invention is incorporated. It is a perspective view which shows the transformer in which the electromagnetic coil insulation film which concerns on Embodiment 2 of this invention was integrated, Comprising: (a) is the assembly state figure, (b) is the decomposition | disassembly state figure.

Embodiments of the present invention will be described below.
Embodiment 1 of the Invention

FIG. 1 shows Embodiment 1 of the present invention (embodiment in which the electromagnetic coil insulating film according to the present invention is applied to a motor).
<Configuration of motor>

  As shown in FIG. 1, the motor 1 has a cylindrical housing 2, and a stator (stator) 3 is attached in the housing 2 along the inner peripheral surface thereof. The stator 3 includes a cylindrical iron core 8 and a plurality of coils 9 arranged so as to be arranged along the inner side of the iron core 8. These coils 9 are electrically insulated from each other in such a manner that each coil 9 is covered with an electromagnetic coil insulating film 10. A cylindrical columnar output shaft 5 is supported at the center of the housing 2 via two bearings 6 so as to be rotatable in the direction of arrow M about the axis CT1. A cylindrical rotor (rotor) 7 is attached to the peripheral surface of the output shaft 5 so as to be able to rotate in the internal space of the stator 3 as the output shaft 5 rotates.

  Here, the electromagnetic coil insulating film 10 is made of liquid crystal polyester, and the liquid crystal polyester has solvent solubility and has a flow start temperature of 250 ° C. or higher. The thickness of the electromagnetic coil insulating film 10 can be appropriately selected according to the output of the motor 1, the arrangement state of the coil 9, etc., but if it is too thin, the insulating function that is the original function of the electromagnetic coil insulating film 10 is obtained. However, since the molding processability disappears as the thickness increases, it is desirable that the insulating film and the molding processability are both within a range (for example, 1-1000 μm).

Hereinafter, liquid crystal polyester as a raw material for the electromagnetic coil insulating film 10, a solution composition containing the liquid crystal polyester and a solvent (solvent), and a method for producing the electromagnetic coil insulating film 10 using the solution composition will be described in order. .
<Liquid crystal polyester>

The liquid crystal polyester used in the present invention is a polyester that exhibits optical anisotropy at the time of melting and has the property of forming an anisotropic melt at a temperature of 450 ° C. or lower. The liquid crystalline polyester used in the present invention has structural units represented by the following formulas (1), (2) and (3), and a structure represented by the formula (1) with respect to the total of all the structural units. The unit (hereinafter referred to as “formula (1) structural unit”) is 30.0 to 60.0 mol%, and the structural unit represented by formula (2) (hereinafter referred to as “formula (2) structural unit”). It is preferably 20.0 to 35.0 mol% and 20.0 to 35.0 mol% of the structural unit represented by the formula (3) (hereinafter referred to as “formula (3) structural unit”).
⁽¹⁾ -O-Ar 1 -CO-
(2) —CO—Ar ² —CO—
⁽³⁾ -X-Ar 3 -Y-
(In the formula, Ar ¹ represents phenylene or naphthylene, Ar ² represents phenylene, naphthylene, or a group represented by the following formula (4), and Ar ³ represents a group represented by phenylene or the following formula (4). And X and Y each independently represent O or NH, wherein the hydrogen atom bonded to the aromatic ring of Ar ¹ , Ar ² and Ar ³ is substituted with an alkyl group or an aryl group. May be good.)
^{(4) -Ar 11 -Z-Ar} 12 -
(In the formula, Ar ¹¹ and Ar ¹² each independently represent phenylene or naphthylene, and Z represents O, CO, or SO _2. )

In addition, an alkyl group or an aryl group may be partially bonded to the aromatic rings of Ar ¹ , Ar ^2, and Ar ³ , but from the viewpoint of flame retardancy, it is preferable that no alkyl group is bonded. preferable. That is, since an alkyl group generally has low flame retardancy, it is preferable to reduce it as much as possible.

In Ar ¹ , Ar ² , Ar ³ , Ar ¹¹ and Ar ¹² , phenylene includes all isomers (o-phenylene, m-phenylene, p-phenylene). From the viewpoint of availability, p -Phenylene is most preferred. In Ar ¹ , Ar ² , Ar ³ , Ar ¹¹ and Ar ¹² naphthylene includes all isomers.

  Here, the structural unit of the formula (1) is a structural unit derived from an aromatic hydroxycarboxylic acid, and examples of the aromatic hydroxycarboxylic acid include parahydroxybenzoic acid, metahydroxybenzoic acid, 2-hydroxy-6- Examples thereof include naphthoic acid, 2-hydroxy-3-naphthoic acid, 1-hydroxy-4-naphthoic acid and the like. When the structural unit (1) is contained within a range of 30.0 to 60.0 mol%, preferably within a range of 35.0 to 60.0 mol%, based on the total of all the structural units. Even more preferred. The liquid crystal polyester containing the structural unit of the formula (1) at such a mole fraction tends to have excellent solubility in a solvent while maintaining sufficient liquid crystallinity. Furthermore, considering the availability of the aromatic hydroxycarboxylic acid from which the structural unit (1) is derived, the aromatic hydroxycarboxylic acid may be p-hydroxybenzoic acid and / or 2-hydroxy-6-naphthoic acid. Acid is preferred.

  Further, the structural unit of the formula (2) is a structural unit derived from an aromatic dicarboxylic acid, and examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, and 1,5-naphthalene. Examples thereof include dicarboxylic acid, diphenyl ether-4,4′-dicarboxylic acid, diphenylsulfone-4,4′-dicarboxylic acid, and diphenyl ketone-4,4′-dicarboxylic acid. When the structural unit (2) is contained within a range of 20.0 to 35.0 mol%, preferably within a range of 30.0 to 32.5 mol%, based on the total of all the structural units. Even more preferred. The liquid crystal polyester containing the structural unit of the formula (2) at such a mole fraction tends to have excellent solubility in a solvent while maintaining sufficient liquid crystallinity. Furthermore, considering the availability of the aromatic dicarboxylic acid from which the structural unit (2) is derived, the aromatic dicarboxylic acid is selected from the group consisting of terephthalic acid, isophthalic acid and 2,6-naphthalenedicarboxylic acid. It is preferable that it is at least one selected.

  Furthermore, the structural unit of the formula (3) is a structural unit derived from an aromatic diol, an aromatic amine having a phenolic hydroxyl group (phenolic hydroxyl group) or an aromatic diamine. Examples of the aromatic diol include hydroquinone, 4,4′-dihydroxybiphenyl, resorcin, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, bis (4-hydroxyphenyl) ether, bis -(4-hydroxyphenyl) ketone, bis- (4-hydroxyphenyl) sulfone and the like can be mentioned. Examples of the aromatic amine having a phenolic hydroxyl group include 4-aminophenol (p-aminophenol) and 3-aminophenol (m-aminophenol). As the aromatic diamine, Examples include 1,4-phenylenediamine and 1,3-phenylenediamine.

  In order to further improve the liquid crystallinity of the liquid crystal ester, the molar ratio of the formula (2) structural unit to the formula (3) structural unit is [formula (2) structural unit] / [formula (3) structural unit]. The range of 0.9 / 1.0 to 1.0 / 0.9 is preferable.

The liquid crystalline polyester used in the present invention has solvent solubility, and such solvent solubility means that it dissolves in a solvent at a temperature of 50 ° C. at a concentration of 1% by mass or more. The solvent in this case is any one of suitable solvents used for preparing the solution composition, and details will be described later. As such a solvent-soluble liquid crystal polyester, those containing a structural unit derived from an aromatic amine having a phenolic hydroxyl group and / or a structural unit derived from an aromatic diamine as the structural unit of the formula (3) are preferable. . That is, as the structural unit of the formula (3), a structural unit in which at least one of X and Y is NH (for example, a structural unit represented by the formula (3 ′); hereinafter referred to as “the formula (3 ′) structural unit”). Is preferable in that the solvent solubility in a suitable solvent (aprotic polar solvent) described later tends to be excellent. In particular, it is preferable that substantially all the structural units of the formula (3) are the structural units of the formula (3 ′). Further, the structural unit of the formula (3 ′) is advantageous in that the liquid crystal polyester has sufficient solvent solubility, and further the hygroscopic property of the liquid crystal polyester is further lowered.
(3 ′) — X—Ar ³ —NH—
(In the formula, Ar ³ and X have the same meaning as in formula (3).)

  The structural unit of the formula (3 ′) is preferably contained in a range of 30.0 to 32.5 mol% with respect to the total of all the structural units, and as a result, the solvent solubility is further improved. Thus, the liquid crystal polyester having the structural unit of the formula (3 ′) as the structural unit of the formula (3) has the solubility of the solvent in the solvent and the low water absorption, and the electromagnetic coil insulating film 10 using the solution composition. There is also an advantage that manufacture becomes easier.

  Next, the manufacturing method of liquid crystalline polyester is demonstrated.

  This liquid crystal polyester can be produced by various known methods. In the case of producing a suitable liquid crystal polyester, that is, a liquid crystal polyester comprising the structural unit of formula (1), the structural unit of formula (2) and the structural unit of formula (3), at least a part of monomers derived from these structural units is ester-forming A method of producing a liquid crystal polyester by polymerization after conversion to an amide-forming derivative is preferable because the operation is simple.

  This ester-forming / amide-forming derivative will be described with examples.

  As an ester-forming / amide-forming derivative of a monomer having a carboxyl group, such as an aromatic hydroxycarboxylic acid or an aromatic group dicarboxylic acid, the carboxyl group promotes a reaction to form a polyester or polyamide. Esters such as acid chlorides and acid anhydrides and esters with alcohols and ethylene glycol are used so that the carboxyl group generates polyester or polyamide by transesterification or amide exchange reaction. What is formed is mentioned.

  As an ester-forming / amide-forming derivative of a monomer having a phenolic hydroxyl group, such as an aromatic hydroxycarboxylic acid or aromatic diol, a phenolic hydroxyl group is formed so as to form a polyester or a polyamide by a transesterification reaction. Are those that form esters with carboxylic acids.

  Examples of the amide-forming derivative of a monomer having an amino group, such as an aromatic diamine, include those in which an amino group forms an amide with a carboxylic acid so that a polyamide is formed by an amide exchange reaction. Can be mentioned.

  Among these, in order to produce a liquid crystal polyester more easily, an aromatic hydroxycarboxylic acid, an aromatic diol, an aromatic amine having a phenolic hydroxyl group, an phenolic hydroxyl group such as an aromatic diamine, and / or an amino group are used. After acylating the monomer with fatty acid anhydride into an ester-forming / amide-forming derivative (acylated product), the acyl group of this acylated product and the carboxy group of the monomer having a carboxy group are transesterified and transamidated. Particularly preferred is a method for producing a liquid crystal polyester by polymerizing in such a manner as to produce the above. Such a liquid crystal polyester manufacturing method is disclosed in, for example, Japanese Patent Application Laid-Open Nos. 2002-220444 and 2002-146003.

  In acylation, the addition amount of fatty acid anhydride is preferably 1.0 to 1.2 times equivalent to the total of phenolic hydroxyl group and amino group, and 1.05 to 1.1 times equivalent. Is more preferable. This is because when the amount of fatty acid anhydride added is less than 1.0 times equivalent, acylated products and raw material monomers tend to sublimate during polymerization, and the reaction system tends to clog. Conversely, when the amount exceeds 1.2 times equivalent This is because the liquid crystal polyester obtained tends to be colored significantly.

  The acylation is preferably performed at 130 to 180 ° C. for 5 minutes to 10 hours, more preferably at 140 to 160 ° C. for 10 minutes to 3 hours. The fatty acid anhydride used for the acylation is preferably acetic anhydride, propionic anhydride, butyric anhydride, isobutyric anhydride or a mixture of two or more selected from these from the viewpoints of price and handleability. Acetic anhydride.

  The polymerization following acylation is preferably carried out at 130 to 400 ° C. while raising the temperature at a rate of 0.1 to 50 ° C./min, and at 150 to 350 ° C. at a rate of 0.3 to 5 ° C./min. More preferably. In this polymerization, the acyl group of the acylated product is preferably 0.8 to 1.2 times equivalent to the carboxyl group.

  In the case of acylation and / or polymerization, in order to shift the equilibrium state based on Le Chatelier's principle, it is preferable to distill out the by-produced fatty acids and unreacted fatty acid anhydrides by evaporating etc. .

  The acylation or polymerization may be performed in the presence of a catalyst. As this catalyst, those conventionally known as polyester polymerization catalysts can be used, such as magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, antimony trioxide and the like. And organic compound catalysts such as N, N-dimethylaminopyridine and N-methylimidazole.

  However, if a catalyst containing a metal is used, this metal will be mixed as an impurity in the liquid crystal polyester, and the insulating property of the electromagnetic coil insulating film 10 may be impaired. From such a viewpoint, among the above catalysts, organic compound catalysts are preferable, and heterocyclic compounds containing two or more nitrogen atoms such as N, N-dimethylaminopyridine and N-methylimidazole are particularly preferably used (for example, JP (See 2002-146003). This catalyst is usually charged together with the monomer, and it is not always necessary to remove it after acylation. If this catalyst is not removed, it is possible to proceed directly from polymerization to polymerization.

  The liquid crystalline polyester obtained by such polymerization can be used as it is in the present invention as long as its flow start temperature is 250 ° C. or higher, but in order to further improve the properties of heat resistance and liquid crystallinity, Further, it is preferable to increase the molecular weight, and it is preferable to perform solid-state polymerization for increasing the molecular weight.

  A series of operations relating to this solid phase polymerization will be described. The relatively low molecular weight liquid crystal polyester obtained by the above polymerization is taken out and pulverized into powder or flakes. Subsequently, the solid phase polymerization is performed by subjecting the pulverized liquid crystal polyester to a heat treatment in a solid state at a temperature of 20 to 350 ° C. for 1 to 30 hours in an atmosphere of an inert gas such as nitrogen, for example. Can be implemented. This solid phase polymerization may be performed with stirring, or may be performed in a state of standing without stirring. From the viewpoint of obtaining a liquid crystalline polyester having a suitable flow start temperature described later, the preferred conditions for this solid phase polymerization will be described in detail. The reaction temperature is preferably higher than 210 ° C, and more preferably 220 to 350 ° C. Is within the range. The reaction time is preferably selected from 1 to 10 hours.

  Since the liquid crystalline polyester used in the present invention has a flow start temperature of 250 ° C. or higher, a film having excellent heat resistance can be formed. From this point of view, the flow start temperature is preferably 260 ° C. or higher. In addition, the flow start temperature here means the temperature at which the melt viscosity of the liquid crystal polyester is 4800 Pa · s or less under a pressure of 9.8 MPa in the evaluation of the melt viscosity by a flow tester. The flow initiation temperature is well known to those skilled in the art as a measure of the molecular weight of the liquid crystal polyester (for example, Naoyuki Koide, “Liquid Crystal Polymer—Synthesis / Molding / Application”, pages 95 to 105). CMC, published June 5, 1987).

Moreover, although the upper limit of the flow start temperature of liquid crystalline polyester is determined in the range in which the solvent solubility of this liquid crystalline polyester is maintained, it is 300 degrees C or less suitably. If the flow start temperature is 300 ° C. or lower, the solubility of the liquid crystal polyester in the solvent becomes better, and when the solution composition described later is obtained, the viscosity does not increase significantly. There is a tendency for the handleability to be good. From this viewpoint, the upper limit of the flow start temperature is more preferably 290 ° C. or lower. In order to control the flow start temperature of the liquid crystal polyester within such a suitable range, the polymerization conditions for the solid phase polymerization may be optimized as appropriate.
<Solution composition>

  In order to obtain the electromagnetic coil insulating film 10 according to the present invention, it is preferable to use a solution composition containing a liquid crystal polyester and a solvent, particularly a solution composition in which the liquid crystal polyester is dissolved in a solvent.

  As the liquid crystal polyester used in the present invention, when the above-mentioned preferred liquid crystal polyester, particularly the liquid crystal polyester containing the structural unit (3 ′) is used, the liquid crystal polyester is sufficient for an aprotic solvent containing no halogen atom. Expresses good solubility. Here, the aprotic solvent not containing a halogen atom is, for example, an ether solvent such as diethyl ether, tetrahydrofuran or 1,4-dioxane; a ketone solvent such as acetone or cyclohexanone; an ester solvent such as ethyl acetate; Lactone solvents such as γ-butyrolactone; carbonate solvents such as ethylene carbonate and propylene carbonate; amine solvents such as triethylamine and pyridine; nitrile solvents such as acetonitrile and succinonitrile; N, N-dimethylformamide and N, N Amide solvents such as dimethylacetamide, tetramethylurea and N-methylpyrrolidone; Nitro solvents such as nitromethane and nitrobenzene; Sulfur solvents such as dimethyl sulfoxide and sulfolane; Hexamethyl phosphate amide and Tri n-butyl phosphorus It includes phosphorus-based solvents such as. In addition, the solvent solubility of the above-mentioned liquid crystalline polyester indicates that it is soluble in at least one aprotic solvent selected from these.

  In order to further improve the solvent solubility of the liquid crystal polyester and make it easier to obtain a solution composition, it is preferable to use an aprotic polar solvent having a dipole moment of 3 to 5 among the exemplified solvents. Specifically, amide solvents and lactone solvents are preferable, and N, N′-dimethylformamito (DMF), N, N′-dimethylacetamide (DMAc), and N-methyl-2-pyrrolidone (NMP) are preferable. More preferably, it is used. Furthermore, when the solvent is a highly volatile solvent having a boiling point of 180 ° C. or less at 1 atm, there is an advantage that the solvent can be easily removed after the electromagnetic coil insulating film 10 is formed. From this viewpoint, DMF and DMAc are particularly preferable.

  When the aprotic solvent as described above is used in the solution composition, it is preferable to dissolve 20 to 50 parts by mass of the liquid crystalline polyester with respect to 100 parts by mass of the aprotic solvent. More preferably. This is because when the content of the liquid crystal polyester with respect to the solution composition is within such a range, the electromagnetic coil insulation film 10 is formed and then the solvent used in the solution composition is removed by drying. This is because there is a tendency that inconveniences such as thickness unevenness occur in the film 10 are unlikely to occur.

  In addition, the solution composition includes a resin other than the liquid crystal polyester, for example, polypropylene, polyamide, polyester, polyphenylene sulfide, polyether ketone, polycarbonate, polyether sulfone, polyphenyl ether, within the range not impairing the object of the present invention. And its modified products, thermoplastic resins such as polyetherimide: elastomer represented by a copolymer of glycidyl methacrylate and polyethylene; one kind of thermosetting resin such as phenol resin, epoxy resin, polyimide resin, cyanate resin or the like Two or more kinds may be added. However, even when such other resins are used, these other resins are also preferably soluble in the solvent used in the solution composition.

  Further, this solution composition has a silica, alumina, titanium oxide, barium titanate, strontium titanate for the purpose of improving dimensional stability and thermal conductivity, as long as the effects of the present invention are not impaired. Inorganic fillers such as aluminum hydroxide and calcium carbonate; organic fillers such as cured epoxy resin, cross-linked benzoguanamine resin and cross-linked acrylic polymer; one or two of various additives such as silane coupling agents, antioxidants and ultraviolet absorbers More than seeds may be added.

  Moreover, this solution composition may remove the fine foreign material contained in a solution by the filtration process using a filter etc. as needed.

Furthermore, this solution composition may be subjected to a defoaming treatment as necessary.
<Method for producing electromagnetic coil insulating film>

  The electromagnetic coil insulating film 10 according to the present invention can be manufactured, for example, by the method described below.

  First, in the solution composition preparation step, the liquid crystal polyester is dissolved in a solvent, preferably an aprotic solvent, to prepare a solution composition as described above.

  Next, the process proceeds to a solution composition coating step, and the solution composition is cast on a suitable support substrate. For such cast coating, for example, roller coating, dip coating, spray coating, etc. Known methods such as a method, a spinner coating method, a curtain coating method, a slot coating method, and a screen printing method can be used. In addition, the support substrate has a smooth surface, and has sufficient durability against ripening treatment after the casting of the solution composition without being significantly impaired to the solution composition to be used. What is necessary is just to have. Examples of such a supporting substrate include a glass plate, a SUS plate, a copper foil, or a SUS foil.

  Finally, the process proceeds to the film forming step, and the solvent is removed from the solution composition thus cast-coated on the supporting substrate, thereby forming a film on the supporting substrate. The method for removing the solvent is not particularly limited, but it is preferably performed by evaporating the solvent. Examples of the method for evaporating the solvent include methods such as heating, decompression, and ventilation. Among these, from the viewpoint of production efficiency and handleability, a method of heating and evaporating is preferable, and a method of heating and evaporating while ventilating is more preferable.

  For example, the heat treatment when N-methyl-2-pyrrolidone (boiling point: 204 ° C.) is used for the preparation of the solution composition will be described. First, preliminary drying is performed at 50 to 60 ° C. for about 3 hours. If the temperature of this preliminary drying is too low, not only will drying take time, but thickness unevenness will easily occur in the resulting electromagnetic coil insulating film 10. On the other hand, when the temperature of preliminary drying is too high, the smoothness of the electromagnetic coil insulating film 10 may be impaired due to rapid evaporation of the solvent. After this preliminary drying, heat treatment is further performed. Examples of the treatment conditions at that time include a method of performing a heat treatment at 240 to 330 ° C. for 1 to 30 hours in an atmosphere of an inert gas such as nitrogen. In order to further improve the heat resistance of the electromagnetic coil insulating film 10 to be obtained, it is preferable that the heat treatment is performed by ripening so that the temperature exceeds 250 ° C. More preferably, the ripening treatment is performed within the range of ° C. Moreover, it is preferable from the point of productivity that the processing time of this heat processing is selected from 1 to 10 hours. Thus, the liquid crystal polyester can be further increased in molecular weight by performing the heat treatment after the preliminary drying.

  Here, the manufacturing operation of the electromagnetic coil insulating film 10 according to the present invention is completed.

  The electromagnetic coil insulating film 10 may be subjected to a surface treatment as necessary within a range that does not impair the characteristics required for the electromagnetic coil insulating film 10. Examples of the surface treatment method include corona discharge treatment, flame treatment, sputtering treatment, solvent treatment, UV treatment, and plasma treatment.

  The electromagnetic coil insulating film 10 according to the present invention thus obtained is excellent in flame retardancy because it is made of liquid crystal polyester.

  In order to verify this, a vertical combustion test defined in UL standard 94 was performed on the electromagnetic coil insulating film 10 according to the present invention. As a result, this electromagnetic coil insulating film 10 exhibited high flame retardancy that satisfies the V0 standard.

  Moreover, since the electromagnetic coil insulating film 10 which concerns on this invention is comprised from the liquid crystalline polyester whose flow start temperature is 250 degreeC or more, it is excellent in heat resistance. The electromagnetic coil insulating film 10 composed of such a liquid crystal polyester does not soften or break even when heat is generated due to motor operation or the like (maximum reached temperature of about 100 ° C.).

  Furthermore, since the electromagnetic coil insulating film 10 according to the present invention is made of liquid crystal polyester having a low water absorption rate, it is excellent in water resistance.

  In order to verify this, even if the electromagnetic coil insulating film 10 of the present invention is left in a high temperature and high humidity atmosphere such as a temperature of 85 ° C. and a relative humidity of 85% RH for a long period of 168 hours, the water absorption is 0. It was about 4% by mass.

  In addition, the electromagnetic coil insulating film 10 according to the present invention thus obtained can avoid a decrease in tear strength in a specific direction because the molecules of the liquid crystal polyester are randomly oriented and the anisotropy disappears. . As a result, the degree of freedom when the electromagnetic coil insulating film 10 is bent is increased, and when the coils 9 are insulated from each other using the electromagnetic coil insulating film 10, the electromagnetic coil insulating film 10 is bent according to the outer shape of the coil 9. Is also possible.

As described above, the electromagnetic coil insulating film 10 according to the present invention is excellent not only in electrical insulation but also in flame retardancy, heat resistance and water resistance, and has excellent molding processability. Since the degree of freedom is high, practical durability of the motor 1 can be enhanced by assembling the motor 1 using the electromagnetic coil insulating film 10.
[Embodiment 2 of the Invention]

FIG. 2 shows Embodiment 2 of the present invention (embodiment in which the electromagnetic coil insulating film according to the present invention is applied to a transformer).
<Transformer configuration>

  As shown in FIG. 2, the transformer 11 has a rectangular parallelepiped box-shaped casing 12, and the upper surface of the casing 12 is open. In the casing 12, two (primary side and secondary side) coils 13 are accommodated in such a manner that the interlayer and upper and lower sides thereof are insulated and laminated by electromagnetic coil insulating films 15, respectively. A pair of magnetic cores 16 are assembled to the casing 12 so as to sandwich the casing 12 from above and below so as to form a magnetic path around the coil 13.

  And each electromagnetic coil insulation film 15 is comprised from liquid crystal polyester similarly to the electromagnetic coil insulation film 10 for motors in Embodiment 1 mentioned above, and this liquid crystal polyester has solvent solubility, and a flow start The temperature is 250 ° C. or higher. The thickness of the electromagnetic coil insulating film 15 can be appropriately selected according to the output of the transformer 11 and the arrangement state of the coil 13, but if it is too thin, the insulating function that is the original function of the electromagnetic coil insulating film 15 is achieved. However, since the molding processability disappears as the thickness increases, it is desirable that the insulating film and the molding processability are both within a range (for example, 1-1000 μm).

  Moreover, about the liquid crystal polyester used as the raw material of this electromagnetic coil insulation film 15, the solution composition containing this liquid crystal polyester and a solvent (solvent), and the manufacturing method of the electromagnetic coil insulation film 15 using this solution composition are mentioned above. This is the same as the first embodiment.

  Therefore, in these electromagnetic coil insulation films 15, there exists the same effect as the electromagnetic coil insulation film 10 for motors in Embodiment 1 mentioned above. That is, the electromagnetic coil insulating film 15 according to the present invention is excellent not only in electrical insulation but also in flame retardancy, heat resistance and water resistance, and has excellent moldability, so that it can be freely bent. Therefore, if the transformer 11 is assembled using this electromagnetic coil insulating film 15, the practical durability of the transformer 11 can be enhanced.

  The present invention can be applied to a motor used in a drive system of a vehicle such as a train, and a large transformer used in a power plant / substation.

DESCRIPTION OF SYMBOLS 1 ... Motor 2 ... Housing 3 ... Stator 5 ... Output shaft 6 ... Bearing 7 ... Rotor 8 ... Iron core 9 ... Coil 10 ... Electromagnetic coil insulation film for motor 11 ... Transformer 12 ... Casing 13 ... Coil 15 ... Electromagnetic coil insulation film for transformer 16 ... Magnetic core

Claims (8)

  An electromagnetic coil insulating film comprising a liquid crystal polyester.   The electromagnetic coil insulating film according to claim 1, wherein the liquid crystal polyester has solvent solubility.   The electromagnetic coil insulating film according to claim 1, wherein the liquid crystal polyester has a flow start temperature of 250 ° C. or higher. The liquid crystalline polyester has structural units represented by the following formulas (1), (2) and (3), and the structural unit represented by the formula (1) is 30.0 with respect to the total of all structural units. A liquid crystalline polyester having a structural unit represented by formula (2) of 20.0-35.0 mol% and a structural unit represented by formula (3) of 20.0-35.0 mol% The electromagnetic coil insulating film according to claim 1, wherein the electromagnetic coil insulating film is provided.
⁽¹⁾ -O-Ar 1 -CO-
(2) —CO—Ar ² —CO—
⁽³⁾ -X-Ar 3 -Y-
(In the formula, Ar ¹ represents phenylene or naphthylene, Ar ² represents phenylene, naphthylene, or a group represented by the following formula (4), and Ar ³ represents a group represented by phenylene or the following formula (4). And X and Y each independently represent O or NH, wherein the hydrogen atom bonded to the aromatic ring of Ar ¹ , Ar ² and Ar ³ is substituted with an alkyl group or an aryl group. May be good.)
^{(4) -Ar 11 -Z-Ar} 12 -
(In the formula, Ar ¹¹ and Ar ¹² each independently represent phenylene or naphthylene, and Z represents O, CO, or SO _2. )   The electromagnetic coil insulating film according to claim 4, wherein at least one of X and Y of the structural unit represented by the formula (3) is NH.   The liquid crystal polyester has a total of 30.0 to 60.0 mol% of structural units derived from p-hydroxybenzoic acid and structural units derived from 2-hydroxy-6-naphthoic acid, a structural unit derived from terephthalic acid, The total of structural units derived from isophthalic acid and structural units derived from 2,6-naphthalenedicarboxylic acid is 20.0 to 35.0 mol%, and structural units derived from 4-aminophenol are 20.0 to 35.0. The electromagnetic coil insulating film according to any one of claims 1 to 3, wherein the electromagnetic coil insulating film is a mol% liquid crystal polyester.   A motor comprising the electromagnetic coil insulating film according to claim 1.   A transformer comprising the electromagnetic coil insulating film according to claim 1.

Images