WO2014184859A1 - Epoxy resin composition, epoxy resin curing agent, motor, and axial gap-type motor - Google Patents

Epoxy resin composition, epoxy resin curing agent, motor, and axial gap-type motor Download PDF

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Publication number
WO2014184859A1
WO2014184859A1 PCT/JP2013/063342 JP2013063342W WO2014184859A1 WO 2014184859 A1 WO2014184859 A1 WO 2014184859A1 JP 2013063342 W JP2013063342 W JP 2013063342W WO 2014184859 A1 WO2014184859 A1 WO 2014184859A1
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Prior art keywords
epoxy resin
stator
resin composition
cured
composition according
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PCT/JP2013/063342
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French (fr)
Japanese (ja)
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義昭 岡部
啓紀 松本
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株式会社日立製作所
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Priority to JP2015516782A priority Critical patent/JPWO2014184859A1/en
Priority to PCT/JP2013/063342 priority patent/WO2014184859A1/en
Publication of WO2014184859A1 publication Critical patent/WO2014184859A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K15/00—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
    • H02K15/12—Impregnating, heating or drying of windings, stators, rotors or machines
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
    • C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
    • C08G59/40—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the curing agents used
    • C08G59/62—Alcohols or phenols
    • C08G59/621—Phenols
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
    • C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
    • C08G59/68—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the catalysts used
    • C08G59/688—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the catalysts used containing phosphorus
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/34—Silicon-containing compounds
    • C08K3/36—Silica
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/12—Stationary parts of the magnetic circuit
    • H02K1/14—Stator cores with salient poles

Definitions

  • the present invention relates to an epoxy resin composition suitable for manufacturing a stator of an axial gap type motor.
  • the power consumption of all motors used in Japan accounts for about 60% of the total power consumption.
  • the amount and range of use of the motor are expected to further expand in the future, and reduction of energy consumption by increasing the efficiency of the motor is expected as an important means for reducing the environmental load.
  • Accelerating motor efficiency is being promoted in many ways, including downsizing, inverter drive, adoption of a magnet motor, adoption of a strong magnet, high-precision design technology, and application of low-loss materials.
  • the use of strong magnets using rare metals has become the mainstream.
  • rare metals are produced in limited countries, and supply instability and price fluctuations are likely to occur. For this reason, development of strong magnets using materials that can be stably supplied is expected. From such a trend, technology for reducing the amount of rare metal used and development of rare metal-free strong magnets are being actively developed. One of them is a rare metal-free, small and highly efficient axial gap motor.
  • An axial gap type motor uses two disc-shaped magnets, and has a configuration in which a coil part including an iron core, bobbin and winding is sandwiched between these magnets. High efficiency can be achieved, for example, a conductive wire with low resistance can be used.
  • the epoxy resin used in the axial gap type motor is also being studied from the viewpoint of motor reliability and mass productivity.
  • Patent Document 1 discloses an epoxy resin powder coating containing an epoxy resin composed of a novolac type polyfunctional epoxy resin and a bisphenol A type epoxy resin, a curing agent, an inorganic filler, a curing accelerator and a stress relaxation agent as essential components. Further, it is disclosed that bisphenol A type epoxy resin having an average molecular weight of 900 to 2000 is used as a bisphenol A type epoxy resin, and fused crushed silica having an average particle size of 13 ⁇ m is used as an inorganic filler.
  • Patent Document 2 discloses that a phenolic curing agent having a weight average molecular weight of 300 to 1500, an epoxy resin that is liquid at 25 ° C., a compound having a flux activity, and a weight average molecular weight of 10,000 to 1,000,000.
  • An adhesive film containing a membrane resin is disclosed.
  • Patent Document 2 also describes that the adhesive film may contain a silane coupling agent or an inorganic filler containing crushed silica.
  • the epoxy resin described in Patent Document 2 is disclosed as being liquid at 25 ° C. and having a viscosity of 500 to 50000 mPa ⁇ s at 25 ° C., but there is no description regarding molecular weight.
  • An object of the present invention is to obtain a resin composition that enables transfer molding using an inexpensive cresol novolac type epoxy resin and a crushed inorganic filler.
  • the present invention relates to an epoxy resin composition
  • an epoxy resin composition comprising an epoxy resin, an epoxy resin curing agent, and a crushed inorganic filler, wherein the epoxy resin is a cresol novolac type and has a weight average molecular weight of 700 to 1800,
  • the agent is a phenol resin and has a weight average molecular weight of 700 to 1400.
  • an epoxy resin cured product which is inexpensive and excellent in moldability, heat resistance, mechanical strength and impact resistance and has an appropriate thermal expansion coefficient.
  • the resin composition (molding material) applied to the stator used in the axial gap motor is inexpensive, has moldability, heat resistance, mechanical strength and impact resistance, and has an appropriate thermal expansion coefficient. Is required.
  • the cost of the molding material should be as low as possible because it affects the price and profitability of the product using it.
  • the conditions (formability) required for the molding material in transfer molding are as follows: (1) The molding time is within 3 minutes, (2) The gap between the coil portions is as narrow as 200 ⁇ m, and the winding in the stator and coil portions is narrow. It can be filled in a gap or the like of a wire (diameter: more than 1.0 mm). Furthermore, since the size of the 55 kW stator is as large as 250 mm in diameter and 125 mm in height, high fluidity is also required.
  • the molding time affects the mass productivity of the product, it is indispensable to have a time of 3 minutes or less for cost reduction, and it is desirable that post-curing treatment is unnecessary.
  • the motor has a higher heat generation density in the coil due to higher output, smaller size and lighter weight.
  • the temperature of the coil portion reaches 120 to 150 ° C. during operation, and thus the cured material of the molding material is required to have a heat resistance of 150 ° C. or higher over a long period of time.
  • the stator retains the shear strength between the aluminum metal that is the housing and the cured product of the molding material (shear strength at the interface between the cured epoxy resin and the housing) and multiple small stators. Long-term resin strength is required for durability against diamagnetic torque. Also, against thermal and mechanical impacts received during manufacturing and motor driving, the cured resin of the stator is required to have a fracture toughness value with excellent impact resistance that does not crack. .
  • the fracture toughness value is preferably 2.8 MPa ⁇ m or more.
  • the difference in the thermal expansion coefficient between the housing for example, aluminum thermal expansion coefficient: 24 ppm / ° C.
  • the difference in thermal expansion coefficient is preferably within ⁇ 5 ppm / ° C. in an environment at 100 to 150 ° C. when the motor is driven.
  • stator for an axial gap type motor is required to satisfy many unprecedented performances simultaneously.
  • the blending amount of the inorganic filler needs to be 75 wt% or more of the molding material in order to make the thermal expansion coefficient of the cured product of the molding material close to the thermal expansion coefficient of aluminum constituting the housing.
  • a cheap filler is crushing filler.
  • the cured material of the molding material containing the crushing filler has an improved fracture toughness value.
  • the surface area of the crushing filler is larger than the spherical filler often used for general molding materials, and the moldability of the molding material using this is greatly reduced.
  • spherical fillers have been mainly used so far in order to achieve both the moldability of the cured product and the thermal expansion coefficient.
  • spherical fillers are expensive. Therefore, it cannot be used for an inexpensive molding material as in the present invention.
  • the moldability does not deteriorate even when the crushing filler is used, and a narrow gap of 55 kW must be filled.
  • the present inventors have found an epoxy resin composition that can be applied to a stator of an axial gap type motor. Moreover, since a polyfunctional epoxy resin and a polyfunctional curing agent with a limited weight average molecular weight are used, the curing reaction is promoted despite the short molding time, and post-curing treatment after molding becomes unnecessary.
  • the epoxy resin composition (epoxy resin molding material) of the present invention is suitable as a material for a stator of an axial gap type motor.
  • the epoxy resin molding material which is the molding material of the present invention will be described.
  • the epoxy resin composition of the present invention includes at least (A) an epoxy resin, (B) a curing agent, and (C) a crushed inorganic filler.
  • the epoxy resin is a cresol novolac type, and its weight average The molecular weight is 700 to 1800
  • the (B) epoxy resin curing agent is a phenol resin, and its weight average molecular weight is 700 to 1400.
  • the weight average molecular weight can be measured by gel permeation chromatography (GPC).
  • Epoxy resins are bisphenol A type, bisphenol F glycidyl ether type, bisphenol S glycidyl ether type, bisphenol AD glycidyl ether type, phenol novolac type, cresol novolac type, 3,3 ′, 5,5′-tetramethyl-4,4
  • phenol novolak type and the cresol novolak type which are polyfunctional resins are preferable. These may be used alone or in combination of two or more.
  • the weight average molecular weight of the epoxy resin is preferably in the range of 700 to 1800. When the weight average molecular weight exceeds 1800, the heat resistance is improved, but the moldability is lowered. On the other hand, when the weight average molecular weight is less than 700, the moldability is improved, but the heat resistance is lowered, which is not preferable.
  • (A) The epoxy resin and the (B) curing agent are bonded by a reaction between an epoxy group and a hydroxyl group. Therefore, the mixing ratio of (A) epoxy resin and (B) curing agent is adjusted so that the ratio of epoxy groups to hydroxyl groups is 0.90 to 1.10. This ratio is more preferably 0.95 to 1.05.
  • the curing agent used in the present invention is preferably a phenolic curing agent or a novolac type phenolic curing agent, which is a polyfunctional resin, from the viewpoint of cost and strength after curing. These may be used alone or in combination of two or more.
  • the weight average molecular weight of the curing agent is preferably in the range of 700 to 1800.
  • the weight average molecular weight exceeds 1800, the heat resistance is improved, but the moldability of the molding material is lowered.
  • the weight average molecular weight is less than 700, the moldability is excellent, but the heat resistance is greatly lowered, which is not preferable.
  • inorganic fillers include silicon oxide (silica), calcium carbonate, magnesium carbonate, various glasses, talc, barium sulfate, mica, alumina, calcium hydroxide, and the like. Depending on its shape, it can be classified into needle shape, plate shape, spherical shape, crushed shape, etc., but when used as a molding material, it is low cost due to its simple manufacturing method and crushed shape that improves the breaking strength of the cured resin. Is preferred.
  • the above fillers may be used alone or in combination of two or more.
  • a filler size having an average particle size in the range of 2 to 40 ⁇ m, which can be molded in a narrow gap during transfer molding is preferable.
  • the particle diameter exceeds 40 ⁇ m, if there is a narrow gap in the molded part, the filler is caught during molding, and the content of the filler tends to be non-uniform.
  • an inorganic filler having a particle size of less than 2 ⁇ m is not preferable because the surface area of the filler is increased and the fluidity is lowered.
  • the average particle diameter is preferably in the range of 2 to 40 ⁇ m, and the average particle diameter is 4.0 to 6.0 ⁇ m.
  • what carried out surface treatment with various coupling agents can also be used for an inorganic filler.
  • a needle-like or plate-like filler can be blended with the main crushed filler.
  • chopped strands of glass fiber can also be included. Chopped strands are formed by cutting strands (bundles of hundreds to thousands of continuous fibers) to a specified length, and are reinforced with thermoplastic resins such as engineering plastics. It is known as a reinforcing material for BMC (Bulk Molding Compound) in a thermosetting resin.
  • the glass fiber used in the present invention has individual fibers randomly oriented and preferably has a length of 1 to 10 cm.
  • the diameter and hardness of the filament, the number of filaments forming a strand, and the type of surface treatment agent There is no limit. There are no restrictions on the brand of chopped strands, but CS6PE-221, CS6E-401, CS6PB-542, CS6PE-231, CS6PE-401, CS6PE-403, CS6PE-471, CS6PE-472, CS6PE-422, manufactured by Nitto Boseki, CS50E-221, CS25E-221, CS13E-221, CS6E-221, CS3E-221, CS6PA-401, CS25Z-700, and the like.
  • the blended amount of the chopped strand is preferably 3 to 12 wt% of the inorganic filler. If it exceeds 12 wt%, the moldability is greatly reduced, and if it is less than 3 wt%, there is no blending effect.
  • the blending amount is more desirably 5 to 10 wt%.
  • the blending amount of the inorganic filler is preferably 65 to 95 wt%.
  • the blending amount is less than 65 wt%, the difference in thermal expansion coefficient of the cured product of the epoxy resin molding material is 5 ppm / ° C or more compared to aluminum. Therefore, the application to the stator for the axial gap type motor is difficult.
  • the blending amount exceeds 95 wt%, the moldability is greatly reduced.
  • the blending amount is more preferably 74 to 88 wt%.
  • the spiral flow value is a flow test method performed by attaching a die having spiral spiral grooves to an actual transfer molding machine.
  • the spiral flow value is 10 inches or less, it is difficult to apply to a stator or the like of an axial gap type motor that is a narrow space between coil portions.
  • the spiral flow value is 20 to 40 inches.
  • the resin is likely to penetrate between the mold and the molding machine, and thus the productivity is lowered.
  • the present invention is an epoxy resin composition that substantially does not contain a reactive monomer or oligomer such as styrene or methacrylic acid. If reactive monomers and oligomers are included, the odor will become intense during transfer molding, which is not good for the health of workers. Further, it is not preferable in terms of storage stability of the molding material.
  • the molding time in transfer molding is preferably within 3 minutes.
  • the heat-resistant temperature class of the cured material of the molding material is F type (155 ° C.) or higher.
  • F type 155 ° C.
  • type F 155 ° C. is indispensable as the heat resistant temperature class of the cured material of the molding material.
  • the fracture toughness value which is an evaluation item of crack resistance of the cured material of the molding material, was determined according to ASTM D5045-91. A predetermined initial crack was put in a test piece of a molded product, and tensile deformation was performed in the vertical direction, and a stress intensity factor (K IC ) was obtained from a load at the time when complete fracture occurred.
  • the fracture toughness value is less than 2.8 MPa ⁇ m, it is preferable to remove the stator of the molded product from the mold after transfer molding, because cracks and the like are likely to occur in the cured product due to sudden temperature drop or mechanical impact. Absent. Therefore, the fracture toughness value is preferably 2.8 MPa ⁇ m or more.
  • fracture toughness refers to resistance to crack propagation when stress is applied to a material in which a crack exists.
  • the blending of a flexible additive into a resin is known. For example, when rubber particles of flexible additives are blended in the resin, the elastic modulus of the resin decreases, so local heat and mechanical stress generated at the protrusions during molding are alleviated and destroyed. Increases toughness value.
  • the flexible additives include rubbers such as isoprene rubber, butadiene rubber, SBR (styrene-butadiene rubber), silicone rubber, CTBN (reactive terminal carboxy group NBR), polyurethanes, polyesters, Examples include urethane-modified epoxy resins, NBR (acrylonitrile-butadiene rubber), CTBN-modified epoxy resins, and silicone-modified epoxy resins, and one or more kinds of stress relaxation agents can be used.
  • cross-linked NBR particles capable of greatly improving performance when dispersed uniformly in a resin, and core-shell type rubber particles having a primary particle size of 100 ⁇ m or less are preferable.
  • the shear strength between the metal housing of the stator and the molded material cured product is preferably 5 MPa or more. When the shear strength is less than 5 MPa, it is not preferable because cracks and peeling easily occur on the contact surface between the metal housing and the molded material cured product due to vibration and internal / external heat during long-term operation of the motor.
  • the curing accelerator used in the present invention generally known accelerators such as imidazole and phosphorus can be used. However, in the present invention, a phosphorus-based curing accelerator that does not cause self-polymerization of the epoxy resin during curing and is excellent in storage stability of the molding material is particularly preferable.
  • the curing accelerator can be used alone or in combination of two or more.
  • a coloring agent a release agent, a stress relaxation agent, a coupling agent, or a flame retardant can be added to the molding material depending on the purpose.
  • the colorant is not particularly limited, and examples thereof include carbon black, titanium oxide, phthalocyanine, chrome green, lead sulfate, chromium oxide, and cobalt green.
  • the colorant can be used alone or in combination of two or more.
  • Release agents include hydrocarbon release agents such as paraffin wax, microwax, and polyethylene wax, higher fatty acid release agents such as lauric acid, myristic acid, palmitic acid, stearic acid, and arachidic acid, stearylamide, and palmitic amide. And higher aliphatic amide release agents, and natural wax release agents such as carnauba wax and montanic acid wax.
  • the release agent can be used alone or in combination of two or more.
  • the coupling agent examples include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl).
  • the flame retardant has several combinations shown below depending on the mechanism of flame retardancy, but is not particularly limited in the present invention.
  • Antimony oxide includes antimony trioxide and antimony pentoxide.
  • Other metal compounds include zinc sulfate, zinc borate, molybdenum oxide, zinc stannate, tin oxide and the like.
  • phosphorus compounds and halogen compounds examples include aromatic phosphates such as triphenyl phosphate, phosphates containing halogen such as red phosphorus, and the like.
  • Halogen compounds include tetrabromobisphenol A, decabromodiphenyl ether, octabromodiphenyl ether, pentabromodiphenyl ether, tetrabromodiphenyl ether, hexabromocyclododecane, tribromophenol, bis (tribromophenoxyethane), bis (pentabromodiphenylethane) And hexabromobenzene polybromobiphenyl.
  • nitrogen-containing compounds examples include melamine cyanurate, azodicarbonamide, dinitrosopentamethylenetetramine, and tetrazole compounds such as bistetrazole / diammonium and bistetrazole / piperazine. From the viewpoint of flame retardancy or decomposition start temperature, melamine cyanurate, azodicarbonamide, and tetrazole compounds are preferable, and melamine cyanurate and tetrazole compounds are more preferable.
  • the nitrogen-containing compound is not particularly limited to these examples.
  • Manganese compounds include manganese oxide, manganese acetate, manganese sulfate and the like.
  • Zinc compounds include zinc oxide, zinc acetate, zinc sulfate and the like.
  • Metal hydroxide and flame retardant aid examples include aluminum hydroxide and magnesium hydroxide. Flame retardant aids include copper nitrate, iron nitrate, silicone compounds, zinc borate and the like.
  • one or more flame retardants can be used.
  • a flame retardant may not be used.
  • (1) Production of molding material In order to prepare the epoxy resin molding material of the present invention, an epoxy resin, a curing agent, a curing accelerator, an inorganic filler, a flexible additive, a coupling agent, a coloring material, and a release agent are used. After weighing each component, lightly mix in a plastic bag. If necessary, mix flame retardants. Thereafter, kneading is performed using a heat mixing roll to produce a molding material. When the stator of the 55 kW axial gap type motor was transfer molded, a molding material obtained by tableting the kneaded molding material with a tablet molding machine was used. A tablet was put into a pot of a transfer press machine that sandwiched the stator mold, and was heat-molded to obtain a 55 kW axial gap motor stator.
  • Each material was blended at a predetermined ratio and lightly mixed in a plastic bag. Thereafter, the raw material was kneaded using an 8-inch mixing roll (manufactured by Torai Seisakusho, roll size: 200 mm ⁇ ⁇ 500 mm) to produce a molding material.
  • the front roll was 65 ° C. and the rear roll was 55 ° C.
  • the kneading time was 15 to 20 minutes after each material was wound around the roll.
  • the molding material was pulverized with a pulverizer (DB-3200, manufactured by Torai Seisakusho).
  • a tablet molded by a tablet molding machine (PH20AS model, manufactured by Fujiwa Seiki Co., Ltd.) was used. This tablet was preheated to 75 ° C. using a high-frequency preheater (FDP-323 type, manufactured by Fuji Electric Koki Co., Ltd.), put into a pot of a transfer press machine (manufactured by Fujiwa Seiki Co., Ltd.) sandwiching the mold, and molded.
  • the molding conditions are a temperature of 180 ° C., a time of 3.0 minutes, and a molding pressure of 7.5 MPa. There was no post cure.
  • the bending strength was determined by using an autograph universal testing machine (manufactured by Shimadzu, AG-X type 100 kN) using a dumbbell-shaped test piece (size: 12.7 mm ⁇ 127 mm ⁇ 5 mmt) produced by transfer molding. And measured. The measurement was performed at a bending speed of 2 mm / min, a fulcrum distance of 80 mm, and a measurement temperature: room temperature.
  • Coefficient of thermal expansion is determined by thermomechanical analysis according to ASTM-D696 at a heating rate of 2 ° C / min after cutting a round bar of ⁇ 10mm x 100mm produced by transfer molding into a length of about 10mm. The elongation was measured with an apparatus (TMA: UL-9, TM-9300 type) to obtain a coefficient of thermal expansion in the range of 100 to 150 ° C.
  • the flowability of the molding material is determined according to SPI-EMMI-1-66 by transfer molding using a spiral flow measurement mold to produce a spiral molded product. Was evaluated by measuring.
  • the flow length is preferably a value of 25 inches or more.
  • Heat-resistant temperature class Insulating materials are determined in accordance with JIS C4003 (Japanese Industrial Standards) as a heat-resistant temperature class, which is an index of heat-resistant temperature.
  • JIS C4003 Japanese Industrial Standards
  • Y type 90 ° C
  • a type 105 ° C
  • E type 120 ° C.
  • B type 130 ° C.
  • F type 155 ° C.
  • H type 180 ° C.
  • the temperature in parentheses is the maximum allowable temperature.
  • Log (L) a + b / T
  • Log represents a natural logarithm
  • L is a lifetime
  • T is an absolute temperature
  • a and b are constants.
  • the time L is the lifetime of the insulating material
  • the logarithmic lifetime and the temperature of 1 / T are in a linear relationship, and the lifetime is shorter at higher temperatures. Therefore, an accelerated test for thermal deterioration of the molding material was performed, the lifetime at each acceleration temperature was obtained, and the lifetime at a lower temperature was predicted.
  • the acceleration condition for thermally degrading the molding material was determined from an empirical rule that the chemical degradation rate doubles every 10 ° C. increase.
  • the heat resistance temperature class of the epoxy resin molding material of the present invention was subjected to an acceleration test on the assumption that the life of Class F (155 ° C./20000h) was cleared.
  • the cause of motor life is the deterioration of the insulating material that constitutes the coil part that is prone to failure. From this, the heat-resistant temperature class was determined from each temperature using the -10% thermal weight loss rate, which is considered to be a cause of deterioration of the molding material, as the lifetime.
  • Epoxy resin 1 o-cresol novolac type epoxy resin (manufactured by Sumitomo Chemical Co., Ltd., trade name: ESCN-190, Mw 1100, epoxy equivalent 195 g / eq)
  • Epoxy resin 2 o-cresol novolac type epoxy resin (manufactured by Nippon Steel & Sumikin Chemical, trade name: YDCN-700-3, Mw 1500, epoxy equivalent 195 g / eq)
  • Epoxy resin 3 o-cresol novolac type epoxy resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., trade name: YDCN-700-10, Mw2200, epoxy equivalent 206 g / eq)
  • Epoxy resin 4 o-cresol novolac epoxy resin (manufactured by DIC, trade name: Epicron N-660, Mw 680, epoxy equivalent 210 g / eq) Curing agent 1: Novolac type phenol resin
  • Curing accelerator Phosphorus curing accelerator (made by Hokuko Chemical, trade name: TPP-k)
  • Flexibility imparting agent 1 Core-shell type rubber particles (Rohm & Haas, trade name: BTA-731J, primary particle size 100-600 nm)
  • Flexibility imparting agent 2 NBR rubber particles (manufactured by Sanyo Trading Co., Ltd., trade name: VP-501, primary particle size 50-100 nm)
  • Coupling agent trade name: KBM403, manufactured by Shin-Etsu Chemical
  • Mold release agent manufactured by Client Japan, trade name: Ricowax E powder
  • Table 2 shows the compositions of the epoxy resin compositions of Examples and Comparative Examples.
  • All examples and comparative examples shown in this table contain 78% by weight of an inorganic filler with respect to the resin content such as epoxy resin and curing agent.
  • the epoxy resin composition of Example 1 includes an epoxy resin 1, a curing agent 1, an inorganic filler 1, an inorganic filler 2, a curing accelerator, a flexibility imparting agent 1, a flexibility imparting agent 2, a coupling agent and Contains a release agent.
  • the epoxy resin composition of Example 2 is the same as Example 1 except that the epoxy resin 2 and the curing agent 3 are used.
  • Example 3 The epoxy resin composition of Example 3 is the same as Example 1 except that the curing agent 3 is used and the inorganic filler 1 is added more and the inorganic filler 2 is reduced.
  • the epoxy resin composition of Example 4 is the same as Example 1 except that the epoxy resin 2 is used and the curing agent 1 is slightly reduced.
  • the epoxy resin composition of Comparative Example 1 is the same as in Example 1 except that the epoxy resin 3 was used and the amounts of the curing agent 1, the flexibility imparting agent 1 and the flexibility imparting agent 2 were finely adjusted. Same as above.
  • the epoxy resin composition of Comparative Example 2 was the same as Example 1 except that the epoxy resin 4 and the curing agent 2 were used.
  • the epoxy resin composition of Comparative Example 3 uses the epoxy resin 1 as in Examples 1 and 2, uses the curing agent 2 as in Comparative Example 2, and has three types of spherical particles having different average particle diameters as inorganic fillers. Silica (inorganic filler 3) was used.
  • the epoxy resin composition of Comparative Example 4 was the same as Example 1 except that the epoxy resin 2 and the curing agent 3 were used, and the flexibility imparting agent was not used.
  • Table 3 shows the characteristics of Examples and Comparative Examples.
  • Example 1 has a good balance of the characteristic values despite using an inexpensive crushed filler as the main component for the inorganic filler. It can also be seen that Examples 2 to 4 have the same characteristics as Example 1 and are well balanced.
  • Comparative Example 1 was 12 inches, which was lower than that of Examples 1 to 4. Other physical properties were almost the same as in the examples.
  • Comparative Example 2 The spiral flow value of Comparative Example 2 was an excellent value of 42 inches, but the fracture toughness value was greatly reduced to 2.3 MPa ⁇ m.
  • Comparative Example 3 shows an excellent value of 76 inches, but the fracture toughness value was greatly reduced to 2.0 MPa ⁇ m.
  • Comparative Example 4 shows an excellent value of 70 inches, but the fracture toughness value was greatly reduced to 1.2 MPa ⁇ m.
  • the examples of the present invention have a spiral flow value, a shear strength value, a heat resistant temperature class, a thermal expansion, regardless of whether an inexpensive crushed filler is used as a main component compared with the comparative example. It turns out that the balance of each characteristic value of a coefficient and a fracture toughness value is excellent.
  • the epoxy resin composition of the present invention can be used for insulating materials and structural materials of various products including an axial gap type motor.
  • FIG. 1 schematically shows the internal structure of an axial gap motor to which the epoxy resin composition of the present invention is applied.
  • the axial gap type motor has a configuration in which a stator 1 is arranged between two rotors 2 and 3.
  • the stator 1 and the rotors 2 and 3 are accommodated in an aluminum housing 4.
  • a range indicated by a broken line represents a member included in each of the stator 1 and the rotors 2 and 3.
  • a plurality of iron cores 5 are arranged radially with respect to the rotation axes of the rotors 2 and 3.
  • the plurality of iron cores 5 are fixed to the housing 4 with a cured epoxy resin obtained by curing the epoxy resin composition of the present invention.
  • FIG. 2 shows a state in which the stator used in the axial gap type motor of FIG. 1 is fixed, and shows one part of the axial gap type motor divided into two near the central axis.
  • the stator 1 is composed of an iron core 5 and a coil wound around the iron core 5. A gap between the constituent elements of the stator 1 is filled with a cured epoxy resin 6.
  • the stator 1 is fixed to the inner wall of the housing 4 by adhesion.
  • the rotors 2 and 3 are fixed to a shaft 7 (rotating shaft), and the rotors 2 and 3 and the shaft 7 are rotatably supported with respect to the stator 1 and the housing 4 by bearings 8 and 9 having bearings 10. ing.
  • stator 1 Since the stator 1 generates stress due to thermal stress or vibration due to temperature rise or vibration when the motor is driven, the stator 1 is cracked or cracked in the cured epoxy resin 6 or at the interface between the cured epoxy resin 6 and the housing 4. Peeling easily occurs. The destruction of the cured epoxy resin 6 causes a relative position between the plurality of iron cores and an axial deviation of the stator 1, and significantly reduces the performance of the motor.
  • the cured epoxy resin 6 produced using the epoxy resin composition of the present invention has a high heat resistant temperature class, a thermal expansion coefficient comparable to that of aluminum, and a large shear strength and fracture toughness value. Resin cracks are less likely to occur. Therefore, the reliability of the stator 1 is improved, and a highly reliable motor can be obtained.
  • the curing time can be greatly shortened, productivity is improved, and adhesion at the interface between the cured epoxy resin 6 and the housing 4 is greatly increased. Can be improved.
  • an epoxy resin molding material (epoxy resin composition) having excellent moldability can be obtained by combining an inexpensive crushed filler and an epoxy resin and a curing agent with a limited weight average molecular weight. .
  • this epoxy resin molding material a product having a complicated internal structure such as a narrow space can be easily manufactured in a short cycle.
  • the resin cured product is excellent in heat resistance, mechanical strength and long-term reliability.
  • a product manufactured from this epoxy resin composition is inexpensive and suitable for electronic / electrical parts having complicated shapes such as an axial gap type motor.
  • the present invention is useful for manufacturing an automobile using an axial gap type motor, various machine tools, and the like.

Abstract

The present invention involves an epoxy resin composition which includes an epoxy resin, an epoxy resin curing agent, and a granular inorganic filler, wherein the epoxy resin is a cresol novolac type epoxy resin with a weight average molecular weight of 700 to 1800, and the epoxy resin curing agent is a phenol resin with a weight average molecular weight of 700 to 1400. Thus, an epoxy resin curing agent that is inexpensive, has excellent formability, heat resistance, mechanical strength and shock resistance, and that has an appropriate thermal expansion coefficient, can be provided.

Description

エポキシ樹脂組成物、エポキシ樹脂硬化物、モータ及びアキシャルギャップ型モータEpoxy resin composition, cured epoxy resin, motor and axial gap type motor
　本発明は、アキシャルギャップ型モータの固定子の製造に好適なエポキシ樹脂組成物に関する。 The present invention relates to an epoxy resin composition suitable for manufacturing a stator of an axial gap type motor.
　国内で使用される全モータの電力消費量は、全電力消費量の約６割を占める。モータの使用量や使用範囲は、今後更に広がっていくことが予想されており、モータの高効率化によるエネルギ消費量の削減は、低環境負荷への重要な手段として期待されている。 The power consumption of all motors used in Japan accounts for about 60% of the total power consumption. The amount and range of use of the motor are expected to further expand in the future, and reduction of energy consumption by increasing the efficiency of the motor is expected as an important means for reducing the environmental load.
　モータの高効率化は、小型化、インバータ駆動、磁石モータの採用、強磁石の採用、高精度設計技術、低損失材料の適用など、多方面より進められている。その中でも、レアメタルを用いた強力磁石の採用が主流となっている。 Accelerating motor efficiency is being promoted in many ways, including downsizing, inverter drive, adoption of a magnet motor, adoption of a strong magnet, high-precision design technology, and application of low-loss materials. Among them, the use of strong magnets using rare metals has become the mainstream.
　しかし、レアメタルは、産出国が限られており、供給不安や価格変動が起きやすい。そのため、安定供給することができる材料を用いた強力磁石の開発が期待されている。このような時流から、レアメタルの使用量を低減する技術やレアメタルフリーの強力磁石の開発が盛んに行われている。その一つとして、レアメタルフリーで、小型で高効率のアキシャルギャップ型モータがある。 However, rare metals are produced in limited countries, and supply instability and price fluctuations are likely to occur. For this reason, development of strong magnets using materials that can be stably supplied is expected. From such a trend, technology for reducing the amount of rare metal used and development of rare metal-free strong magnets are being actively developed. One of them is a rare metal-free, small and highly efficient axial gap motor.
　アキシャルギャップ型モータは、２枚の円板状のマグネットを使用し、これらのマグネットの間に鉄心、ボビン及び巻き線を含むコイル部を挟む構成を有するものであり、従来型に比べて、電気抵抗の少ない導線を用いることができる等、高効率化が可能である。 An axial gap type motor uses two disc-shaped magnets, and has a configuration in which a coil part including an iron core, bobbin and winding is sandwiched between these magnets. High efficiency can be achieved, for example, a conductive wire with low resistance can be used.
　アキシャルギャップ型モータに用いるエポキシ樹脂も、モータの信頼性や量産性等の観点から検討が進められている。 The epoxy resin used in the axial gap type motor is also being studied from the viewpoint of motor reliability and mass productivity.
　特許文献１には、ノボラック型多官能エポキシ樹脂およびビスフェノールＡ型エポキシ樹脂からなるエポキシ樹脂、硬化剤、無機充填材、硬化促進剤および応力緩和剤を必須成分として含有するエポキシ樹脂系粉体塗料において、ビスフェノールＡ型エポキシ樹脂として平均分子量９００～２０００のビスフェノールＡ型エポキシ樹脂を、無機充填材として平均粒径１３μｍの溶融破砕シリカを用いることが開示されている。 Patent Document 1 discloses an epoxy resin powder coating containing an epoxy resin composed of a novolac type polyfunctional epoxy resin and a bisphenol A type epoxy resin, a curing agent, an inorganic filler, a curing accelerator and a stress relaxation agent as essential components. Further, it is disclosed that bisphenol A type epoxy resin having an average molecular weight of 900 to 2000 is used as a bisphenol A type epoxy resin, and fused crushed silica having an average particle size of 13 μm is used as an inorganic filler.
　特許文献２には、重量平均分子量が３００～１５００であるフェノール系硬化剤と、２５℃で液状であるエポキシ樹脂と、フラックス活性を有する化合物と、重量平均分子量が１万～１００万である成膜性樹脂とを含む接着フィルムが開示されている。特許文献２には、この接着フィルムは、シランカップリング剤や、破砕シリカを含む無機充填剤を含んでいてもよいとの記載もある。 Patent Document 2 discloses that a phenolic curing agent having a weight average molecular weight of 300 to 1500, an epoxy resin that is liquid at 25 ° C., a compound having a flux activity, and a weight average molecular weight of 10,000 to 1,000,000. An adhesive film containing a membrane resin is disclosed. Patent Document 2 also describes that the adhesive film may contain a silane coupling agent or an inorganic filler containing crushed silica.
特開平１０－１３０５４２号公報JP-A-10-130542 特開２０１１－１５５０２７号公報JP 2011-155027 A
　特許文献１に記載された硬化剤の具体例は、分子量８４のジシアンジアミドのみである。 The specific example of the curing agent described in Patent Document 1 is only dicyandiamide having a molecular weight of 84.
　特許文献２に記載されたエポキシ樹脂については、２５℃で液状であること、２５℃における粘度が５００～５００００ｍＰａ・ｓであること等が開示されているが、分子量に関する記載はない。 The epoxy resin described in Patent Document 2 is disclosed as being liquid at 25 ° C. and having a viscosity of 500 to 50000 mPa · s at 25 ° C., but there is no description regarding molecular weight.
　本発明の目的は、安価なクレゾールノボラック型のエポキシ樹脂及び破砕状無機充填剤を用いてトランスファー成形を可能とする樹脂組成物を得ることにある。 An object of the present invention is to obtain a resin composition that enables transfer molding using an inexpensive cresol novolac type epoxy resin and a crushed inorganic filler.
　本発明は、エポキシ樹脂と、エポキシ樹脂硬化剤と、破砕状無機充填剤とを含むエポキシ樹脂組成物において、エポキシ樹脂は、クレゾールノボラック型とし、その重量平均分子量は７００～１８００とし、エポキシ樹脂硬化剤は、フェノール樹脂とし、その重量平均分子量は７００～１４００としたことを特徴とする。 The present invention relates to an epoxy resin composition comprising an epoxy resin, an epoxy resin curing agent, and a crushed inorganic filler, wherein the epoxy resin is a cresol novolac type and has a weight average molecular weight of 700 to 1800, The agent is a phenol resin and has a weight average molecular weight of 700 to 1400.
　本発明によれば、安価で、かつ、成形性、耐熱性、機械的強度及び耐衝撃性に優れ、適切な熱膨張係数を有するエポキシ樹脂硬化物を提供することができる。 According to the present invention, it is possible to provide an epoxy resin cured product which is inexpensive and excellent in moldability, heat resistance, mechanical strength and impact resistance and has an appropriate thermal expansion coefficient.
アキシャルギャップ型モータの内部構造の例を示す模式分解斜視図である。It is a model disassembled perspective view which shows the example of the internal structure of an axial gap type motor. アキシャルギャップ型モータの固定子の状態を示す部分断面図である。It is a fragmentary sectional view which shows the state of the stator of an axial gap type motor.
　アキシャルギャップ型モータに用いる固定子に適用する樹脂組成物（成形材料）は、安価であること、成形性、耐熱性、機械的強度及び耐衝撃性を有すること、並びに適切な熱膨張係数を有することが要求される。 The resin composition (molding material) applied to the stator used in the axial gap motor is inexpensive, has moldability, heat resistance, mechanical strength and impact resistance, and has an appropriate thermal expansion coefficient. Is required.
　以下、これらについて説明する。 These will be described below.
　成形材料のコストは、これを用いた製品の価格や収益性に影響するため、できるだけ安価であることが望ましい。 ¡The cost of the molding material should be as low as possible because it affects the price and profitability of the product using it.
　トランスファー成形において成形材料に要求される条件（成形性）としては、（１）成形時間が３分以内であること、（２）コイル部間のギャップが２００μｍと狭い固定子内及びコイル部の巻き線（直径：１．０ｍｍ超）の隙間等に充填可能であることが挙げられる。さらに、５５ｋＷ用の固定子のサイズは、直径２５０ｍｍ、高さ１２５ｍｍと大きいため、高い流動性も要求される。 The conditions (formability) required for the molding material in transfer molding are as follows: (1) The molding time is within 3 minutes, (2) The gap between the coil portions is as narrow as 200 μm, and the winding in the stator and coil portions is narrow. It can be filled in a gap or the like of a wire (diameter: more than 1.0 mm). Furthermore, since the size of the 55 kW stator is as large as 250 mm in diameter and 125 mm in height, high fluidity is also required.
　成形時間は、製品の量産性に影響するため、低価格化には３分以内が不可欠であり、且つ、後硬化処理が不要であることが望ましい。 ¡Since the molding time affects the mass productivity of the product, it is indispensable to have a time of 3 minutes or less for cost reduction, and it is desirable that post-curing treatment is unnecessary.
　モータは、高出力化や小型・軽量化によりコイル部における発熱密度が上昇する。例えば、５５ｋＷアキシャルギャップ型モータの場合、コイル部の温度は、稼働時に１２０～１５０℃に達するため、成形材料の硬化物は、長期にわたる１５０℃以上の耐熱性が要求される。 The motor has a higher heat generation density in the coil due to higher output, smaller size and lighter weight. For example, in the case of a 55 kW axial gap type motor, the temperature of the coil portion reaches 120 to 150 ° C. during operation, and thus the cured material of the molding material is required to have a heat resistance of 150 ° C. or higher over a long period of time.
　固定子は、ハウジングであるアルミニウム金属と成形材料の硬化物との間のせん断強度（エポキシ樹脂硬化物とハウジングとの界面のせん断強度）や、複数の小固定子を保持するため、成形材料が受ける反磁性トルクに対する耐久性として長期間の樹脂強度が要求される。また、製造の際及びモータの駆動の際に受ける熱的や機械的な衝撃に対して、固定子の樹脂硬化物がクラックを起さない、耐衝撃性に優れた破壊靭性値が要求される。破壊靭性値は、２．８ＭＰａ√ｍ以上が好ましい。 The stator retains the shear strength between the aluminum metal that is the housing and the cured product of the molding material (shear strength at the interface between the cured epoxy resin and the housing) and multiple small stators. Long-term resin strength is required for durability against diamagnetic torque. Also, against thermal and mechanical impacts received during manufacturing and motor driving, the cured resin of the stator is required to have a fracture toughness value with excellent impact resistance that does not crack. . The fracture toughness value is preferably 2.8 MPa√m or more.
　また、固定子は、ハウジング（例えば、アルミニウムの熱膨張係数：２４ｐｐｍ／℃）と樹脂硬化物との熱膨張係数の差が大きいと、環境条件により、樹脂硬化物に各種応力が発生し、クラック等が発生しやすくなる。そのため、モータの駆動時の１００～１５０℃における環境下では、熱膨張係数の差は±５ｐｐｍ／℃以内が好ましい。 In addition, if the difference in the thermal expansion coefficient between the housing (for example, aluminum thermal expansion coefficient: 24 ppm / ° C.) and the cured resin is large, various stresses are generated in the cured resin due to environmental conditions, and the stator cracks. Etc. are likely to occur. Therefore, the difference in thermal expansion coefficient is preferably within ± 5 ppm / ° C. in an environment at 100 to 150 ° C. when the motor is driven.
　このようにアキシャルギャップ型モータ用の固定子は、従来にない多くの性能を同時に満たすことが要求されている。 Thus, a stator for an axial gap type motor is required to satisfy many unprecedented performances simultaneously.
　無機充填剤の配合量は、成形材料の硬化物の熱膨張係数を、ハウジングを構成するアルミニウムの熱膨張係数に近づけるため、成形材料の７５ｗｔ％以上とする必要がある。 The blending amount of the inorganic filler needs to be 75 wt% or more of the molding material in order to make the thermal expansion coefficient of the cured product of the molding material close to the thermal expansion coefficient of aluminum constituting the housing.
　安価な無機充填剤としては、破砕フィラがある。破砕フィラを配合した成形材料の硬化物は、破壊靭性値が向上する。 A cheap filler is crushing filler. The cured material of the molding material containing the crushing filler has an improved fracture toughness value.
　しかし、破砕フィラの表面積が、一般的な成形材料に多く使用されている球状フィラより大きく、これを用いた成形材料の成形性が大きく低下する。そのため、これまでは、硬化物の成形性と熱膨張係数とを両立するため、球状フィラが主に利用されている。しかし、球状フィラは高価である。そのため、本発明のような安価な成形材料には利用できない。 However, the surface area of the crushing filler is larger than the spherical filler often used for general molding materials, and the moldability of the molding material using this is greatly reduced. For this reason, spherical fillers have been mainly used so far in order to achieve both the moldability of the cured product and the thermal expansion coefficient. However, spherical fillers are expensive. Therefore, it cannot be used for an inexpensive molding material as in the present invention.
　そこで、安価な破砕フィラを用いて成形性を向上する手段を検討した。 Therefore, a means for improving the moldability using an inexpensive crushing filler was examined.
　その結果、破砕型充填剤のサイズや量並びにエポキシ樹脂及び硬化剤の重量平均分子量を限定することにより、破砕フィラを用いても成形性が低下せず、狭い空隙を充填しなければならない５５ｋｗのアキシャルギャップ型モータの固定子に適用できるエポキシ樹脂組成物を見出した。また、重量平均分子量を限定した多官能エポキシ樹脂及び多官能硬化剤を用いるため、短い成形時間にもかかわらず、硬化反応が促進され、成形後の後硬化処理が不要となった。 As a result, by limiting the size and amount of the crushing type filler and the weight average molecular weight of the epoxy resin and the curing agent, the moldability does not deteriorate even when the crushing filler is used, and a narrow gap of 55 kW must be filled. The present inventors have found an epoxy resin composition that can be applied to a stator of an axial gap type motor. Moreover, since a polyfunctional epoxy resin and a polyfunctional curing agent with a limited weight average molecular weight are used, the curing reaction is promoted despite the short molding time, and post-curing treatment after molding becomes unnecessary.
　本発明のエポキシ樹脂組成物（エポキシ樹脂成形材料）は、アキシャルギャップ型モータの固定子の材料として好適である。 The epoxy resin composition (epoxy resin molding material) of the present invention is suitable as a material for a stator of an axial gap type motor.
　本発明の成形材料であるエポキシ樹脂成形材料を説明する。 The epoxy resin molding material which is the molding material of the present invention will be described.
　本発明のエポキシ樹脂組成物は、少なくとも（Ａ）エポキシ樹脂、（Ｂ）硬化剤、及び（Ｃ）破砕型無機充填剤を含み、（Ａ）エポキシ樹脂は、クレゾールノボラック型であり、その重量平均分子量が７００～１８００であり、（Ｂ）エポキシ樹脂硬化剤は、フェノール樹脂であり、その重量平均分子量が７００～１４００であることを特徴とする。ここで、重量平均分子量は、ゲル浸透クロマトグラフ（ＧＰＣ）により測定することができる。 The epoxy resin composition of the present invention includes at least (A) an epoxy resin, (B) a curing agent, and (C) a crushed inorganic filler. (A) The epoxy resin is a cresol novolac type, and its weight average The molecular weight is 700 to 1800, and the (B) epoxy resin curing agent is a phenol resin, and its weight average molecular weight is 700 to 1400. Here, the weight average molecular weight can be measured by gel permeation chromatography (GPC).
　エポキシ樹脂は、ビスフェノールＡ型、ビスフェノールＦグリシジルエーテル型、ビスフェノールＳグリシジルエーテル型、ビスフェノールＡＤグリシジルエーテル型、フェノールノボラック型、クレゾールノボラック型、３，３’，５，５’－テトラメチル－４，４’－ジヒドロキシビフェニルグリシジルエーテル型などがあるが、低価格であること、樹脂硬化物の反応性が高いこと、及び強度の観点から、多官能樹脂であるフェノールノボラック型及びクレゾールノボラック型が好ましい。これらは単独でも二種類以上混合しても差し支えない。 Epoxy resins are bisphenol A type, bisphenol F glycidyl ether type, bisphenol S glycidyl ether type, bisphenol AD glycidyl ether type, phenol novolac type, cresol novolac type, 3,3 ′, 5,5′-tetramethyl-4,4 There are '-dihydroxybiphenyl glycidyl ether type and the like. From the viewpoint of low cost, high reactivity of the cured resin, and strength, the phenol novolak type and the cresol novolak type which are polyfunctional resins are preferable. These may be used alone or in combination of two or more.
　また、エポキシ樹脂の重量平均分子量は、７００～１８００の範囲が好ましい。重量平均分子量が１８００を超える場合、耐熱性は向上するが、成形性が低下する。一方、重量平均分子量が７００未満の場合は、成形性は向上するが、耐熱性が低下し、好ましくない。 The weight average molecular weight of the epoxy resin is preferably in the range of 700 to 1800. When the weight average molecular weight exceeds 1800, the heat resistance is improved, but the moldability is lowered. On the other hand, when the weight average molecular weight is less than 700, the moldability is improved, but the heat resistance is lowered, which is not preferable.
　（Ａ）エポキシ樹脂と（Ｂ）硬化剤とは、エポキシ基と水酸基との反応によって結合する。よって、（Ａ）エポキシ樹脂と（Ｂ）硬化剤との混合比率は、化学当量の観点から、エポキシ基と水酸基とが０．９０～１．１０の比率となるように調整する。この比率は、０．９５～１．０５であることが更に望ましい。 (A) The epoxy resin and the (B) curing agent are bonded by a reaction between an epoxy group and a hydroxyl group. Therefore, the mixing ratio of (A) epoxy resin and (B) curing agent is adjusted so that the ratio of epoxy groups to hydroxyl groups is 0.90 to 1.10. This ratio is more preferably 0.95 to 1.05.
　本発明で用いられる硬化剤は、価格及び硬化後の強度の観点から、多官能樹脂であるフェノール系硬化剤及びノボラック型フェノール系硬化剤が好ましい。これらは単独でも二種類以上混合しても差し支えない。 The curing agent used in the present invention is preferably a phenolic curing agent or a novolac type phenolic curing agent, which is a polyfunctional resin, from the viewpoint of cost and strength after curing. These may be used alone or in combination of two or more.
　硬化剤の重量平均分子量は、７００～１８００の範囲が好ましい。重量平均分子量が１８００を超える場合、耐熱性は向上するが、成形材料の成形性が低下する。また、重量平均分子量が７００未満の場合は、成形性に優れる半面、耐熱性の低下が大きく、好ましくない。 The weight average molecular weight of the curing agent is preferably in the range of 700 to 1800. When the weight average molecular weight exceeds 1800, the heat resistance is improved, but the moldability of the molding material is lowered. On the other hand, when the weight average molecular weight is less than 700, the moldability is excellent, but the heat resistance is greatly lowered, which is not preferable.
　充填剤は、極めて多くの種類があり、化学組織、形状、粒子径等の点で変化に富んでいる。その中で、無機充填剤は、酸化ケイ素（シリカ）、炭酸カルシウム、炭酸マグネシウム、各種ガラス、タルク、硫酸バリウム、マイカ、アルミナ、水酸化カルシウムなどがある。その形状により、針状、板状、球状、破砕状等に分類できるが、成形材料に用いた場合、製造法が簡単なため低価格であって、樹脂硬化物の破断強度が向上する破砕状が好ましい。上記の充填剤は、単独でも二種類以上混合しても差し支えない。 ∙ There are many types of fillers, and they are rich in changes in terms of chemical structure, shape, particle diameter, and the like. Among them, inorganic fillers include silicon oxide (silica), calcium carbonate, magnesium carbonate, various glasses, talc, barium sulfate, mica, alumina, calcium hydroxide, and the like. Depending on its shape, it can be classified into needle shape, plate shape, spherical shape, crushed shape, etc., but when used as a molding material, it is low cost due to its simple manufacturing method and crushed shape that improves the breaking strength of the cured resin. Is preferred. The above fillers may be used alone or in combination of two or more.
　特に、トランスファー成形の際、狭ギャップにも成形できる、平均粒径２～４０μｍの範囲のフィラーサイズが好ましい。粒径が４０μｍを超えるものは、成形部品に狭ギャップが存在すると、成形の際に充填剤が引っ掛かり、充填剤の含有割合が不均一になりやすい。一方、粒径２μｍ未満の無機充填剤では、充填剤の表面積が大きくなるため、流動性が低下するため好ましくない。その中で好ましいものは、平均粒径が２～４０μｍの範囲で、その平均粒径は４．０～６．０μｍである。また、無機充填剤は、各種カップリング剤で表面処理したものも使用できる。 In particular, a filler size having an average particle size in the range of 2 to 40 μm, which can be molded in a narrow gap during transfer molding, is preferable. In the case where the particle diameter exceeds 40 μm, if there is a narrow gap in the molded part, the filler is caught during molding, and the content of the filler tends to be non-uniform. On the other hand, an inorganic filler having a particle size of less than 2 μm is not preferable because the surface area of the filler is increased and the fluidity is lowered. Among these, the average particle diameter is preferably in the range of 2 to 40 μm, and the average particle diameter is 4.0 to 6.0 μm. Moreover, what carried out surface treatment with various coupling agents can also be used for an inorganic filler.
　また、無機充填剤として、メインの破砕状充填剤に針状又は板状の充填剤を配合することができる。本発明では、ガラス繊維のチョップドストランドも含むことができる。チョップドストランドは、ストランド（連続した１本の繊維を数百本～数千本束ねたもの）を所定の長さに切断した形状のものであり、エンジニアリングプラスチックスをはじめとする熱可塑性樹脂の補強材、及び熱硬化性樹脂におけるＢＭＣ（Ｂｕｌｋ　Ｍｏｌｄｉｎｇ　Ｃｏｍｐｏｕｎｄ）用の強化材として知られている。 Also, as an inorganic filler, a needle-like or plate-like filler can be blended with the main crushed filler. In the present invention, chopped strands of glass fiber can also be included. Chopped strands are formed by cutting strands (bundles of hundreds to thousands of continuous fibers) to a specified length, and are reinforced with thermoplastic resins such as engineering plastics. It is known as a reinforcing material for BMC (Bulk Molding Compound) in a thermosetting resin.
　本発明において使用するガラス繊維は、個々の繊維がランダムに配向していて、長さは１～１０ｃｍが好ましく、フィラメントの径及び硬さ、ストランドを形成するフィラメントの本数、及び表面処理剤の種類に制限はない。チョップドストランドの銘柄に制限はないが、日東紡績製のＣＳ６ＰＥ－２２１、ＣＳ６Ｅ－４０１、ＣＳ６ＰＢ－５４２、ＣＳ６ＰＥ－２３１、ＣＳ６ＰＥ－４０１、ＣＳ６ＰＥ－４０３、ＣＳ６ＰＥ－４７１、ＣＳ６ＰＥ－４７２、ＣＳ６ＰＥ－４２２、ＣＳ５０Ｅ－２２１、ＣＳ２５Ｅ－２２１、ＣＳ１３Ｅ－２２１、ＣＳ６Ｅ－２２１、ＣＳ３Ｅ－２２１、ＣＳ６ＰＡ－４０１、ＣＳ２５Ｚ－７００等がある。 The glass fiber used in the present invention has individual fibers randomly oriented and preferably has a length of 1 to 10 cm. The diameter and hardness of the filament, the number of filaments forming a strand, and the type of surface treatment agent There is no limit. There are no restrictions on the brand of chopped strands, but CS6PE-221, CS6E-401, CS6PB-542, CS6PE-231, CS6PE-401, CS6PE-403, CS6PE-471, CS6PE-472, CS6PE-422, manufactured by Nitto Boseki, CS50E-221, CS25E-221, CS13E-221, CS6E-221, CS3E-221, CS6PA-401, CS25Z-700, and the like.
　チョップドストランドの配合量は、無機充填剤の３～１２ｗｔ％であるが好ましい。１２ｗｔ％を超えると成形性の低下が大きく、３ｗｔ％未満では配合の効果がない。当該配合量は、５～１０ｗｔ％が更に望ましい。 The blended amount of the chopped strand is preferably 3 to 12 wt% of the inorganic filler. If it exceeds 12 wt%, the moldability is greatly reduced, and if it is less than 3 wt%, there is no blending effect. The blending amount is more desirably 5 to 10 wt%.
　無機充填剤の配合量は、６５～９５ｗｔ％が好ましい。配合量が６５ｗｔ％未満では、エポキシ樹脂成形材料の硬化物の熱膨張係数が、アルミニウムと比較して、その差が５ｐｐｍ／℃以上になるため、アキシャルギャップ型モータへの固定子への適用は難しい。一方、配合量が９５ｗｔ％を超えると、成形性が大きく低下する。当該配合量は、７４～８８ｗｔ％が更に好ましい。 The blending amount of the inorganic filler is preferably 65 to 95 wt%. When the blending amount is less than 65 wt%, the difference in thermal expansion coefficient of the cured product of the epoxy resin molding material is 5 ppm / ° C or more compared to aluminum. Therefore, the application to the stator for the axial gap type motor is difficult. On the other hand, if the blending amount exceeds 95 wt%, the moldability is greatly reduced. The blending amount is more preferably 74 to 88 wt%.
　成形性については、うず巻き（スパイラル）状の溝をもった金型を実際のトランスファー成形機に取り付けて行う流れ試験方法であるスパイラスフロー値で評価する。例えば、スパイラスフロー値が１０インチ以下では、コイル部間が狭い空間であるアキシャルギャップ型モータの固定子等への適用は難しい。好ましくは、スパイラスフロー値は２０～４０インチである。しかし、スパイラスフロー値が４０インチ以上では、金型や成形機の間に樹脂が浸み込みやすいため、生産性が低下する。 ¡Formability is evaluated by the spiral flow value, which is a flow test method performed by attaching a die having spiral spiral grooves to an actual transfer molding machine. For example, when the spiral flow value is 10 inches or less, it is difficult to apply to a stator or the like of an axial gap type motor that is a narrow space between coil portions. Preferably, the spiral flow value is 20 to 40 inches. However, when the spiral flow value is 40 inches or more, the resin is likely to penetrate between the mold and the molding machine, and thus the productivity is lowered.
　また、本発明は、スチレンや、メタクリル酸など、反応性のモノマやオリゴマを実質的に含有しないエポキシ樹脂組成物である。反応性のモノマやオリゴマが含まれると、トランスファー成形の際に臭気が激しくなり、作業員の健康に良くない。また、成形材料の保存安定性の点で好ましくない。 In addition, the present invention is an epoxy resin composition that substantially does not contain a reactive monomer or oligomer such as styrene or methacrylic acid. If reactive monomers and oligomers are included, the odor will become intense during transfer molding, which is not good for the health of workers. Further, it is not preferable in terms of storage stability of the molding material.
　成形材料の成形時間は短い方が、量産性の点で有利である。例えば、トランスファー成形における成形時間は、３分以内が好ましい。 ¡A shorter molding material molding time is advantageous in terms of mass productivity. For example, the molding time in transfer molding is preferably within 3 minutes.
　また、成形材料の硬化物の耐熱温度クラスは、Ｆ種（１５５℃）以上であることが好ましい。理由は、５５ｋＷのアキシャルギャップ型モータの場合、運転時にコイル部の温度が１４０～１５０℃に達するためである。そのため、成形材料の硬化物の耐熱温度クラスは、Ｆ種（１５５℃）が不可欠である。 Moreover, it is preferable that the heat-resistant temperature class of the cured material of the molding material is F type (155 ° C.) or higher. The reason is that in the case of a 55 kW axial gap type motor, the temperature of the coil portion reaches 140 to 150 ° C. during operation. Therefore, type F (155 ° C.) is indispensable as the heat resistant temperature class of the cured material of the molding material.
　成形材料の硬化物の耐クラック性の評価項目である破壊靭性値は、ＡＳＴＭ　Ｄ５０４５－９１に準拠して求めた。成形品の試験片に所定の初期クラックを入れ、上下に引張変形して、完全に破壊が起きた時点の荷重から応力拡大係数（ＫＩＣ）を求めた。 The fracture toughness value, which is an evaluation item of crack resistance of the cured material of the molding material, was determined according to ASTM D5045-91. A predetermined initial crack was put in a test piece of a molded product, and tensile deformation was performed in the vertical direction, and a stress intensity factor (K IC ) was obtained from a load at the time when complete fracture occurred.
　破壊靭性値が２．８ＭＰａ√ｍ未満である場合、トランスファー成形後、金型から成形品の固定子を外す場合、急激な降温や機械的衝撃により、硬化物にクラック等が起こりやすくなるため好ましくない。そのため、破壊靭性値は２．８ＭＰａ√ｍ以上であることが好ましい。 When the fracture toughness value is less than 2.8 MPa√m, it is preferable to remove the stator of the molded product from the mold after transfer molding, because cracks and the like are likely to occur in the cured product due to sudden temperature drop or mechanical impact. Absent. Therefore, the fracture toughness value is preferably 2.8 MPa√m or more.
　ここで、破壊靱性とは、亀裂が存在する材料に応力がかかっている場合、この亀裂進展に対する抵抗力をいう。その値を向上させるには、可とう性添加剤の樹脂中への配合が知られている。例えば、可とう性添加剤のゴム粒子を樹脂中に配合した場合、樹脂の弾性率が低下するため、成形の際に突起部などで発生する局部的な熱や機械的応力が緩和され、破壊靭性値が大きくなる。 Here, fracture toughness refers to resistance to crack propagation when stress is applied to a material in which a crack exists. In order to improve the value, the blending of a flexible additive into a resin is known. For example, when rubber particles of flexible additives are blended in the resin, the elastic modulus of the resin decreases, so local heat and mechanical stress generated at the protrusions during molding are alleviated and destroyed. Increases toughness value.
　可とう性添加剤は、イソプレンゴム、ブタジエンゴム、ＳＢＲ（スチレン・ブタジエンゴム（ｓｔｙｒｅｎｅ－ｂｕｔａｄｉｅｎｅ　ｒｕｂｂｅｒ））、シリコーンゴム、ＣＴＢＮ（反応性末端カルボキシ基ＮＢＲ）等のゴム類、ポリウレタン類、ポリエステル類、ウレタン変性エポキシ樹脂、ＮＢＲ（アクリロニトリル－ブタジエンゴム）、ＣＴＢＮ変性エポキシ樹脂及びシリコーン変性エポキシ樹脂が挙げられるが、単独または二種類以上の応力緩和剤を用いることができる。本発明においては、樹脂中に均一に分散した場合、大幅な性能向上が図られる架橋ＮＢＲ粒子や、一次粒子の粒径が１００μｍ以下のコアシェル型ゴム粒子が好ましい。 The flexible additives include rubbers such as isoprene rubber, butadiene rubber, SBR (styrene-butadiene rubber), silicone rubber, CTBN (reactive terminal carboxy group NBR), polyurethanes, polyesters, Examples include urethane-modified epoxy resins, NBR (acrylonitrile-butadiene rubber), CTBN-modified epoxy resins, and silicone-modified epoxy resins, and one or more kinds of stress relaxation agents can be used. In the present invention, cross-linked NBR particles capable of greatly improving performance when dispersed uniformly in a resin, and core-shell type rubber particles having a primary particle size of 100 μm or less are preferable.
　固定子の金属ハウジングと成形材硬化物とのせん断強度は５ＭＰａ以上であることが好ましい。せん断強度が５ＭＰａ未満である場合、モータの長期運転中に、振動や内外部の熱によって、金属ハウジングと成形材硬化物との接触面でクラックや剥離が起きやすくなるため、好ましくない。 The shear strength between the metal housing of the stator and the molded material cured product is preferably 5 MPa or more. When the shear strength is less than 5 MPa, it is not preferable because cracks and peeling easily occur on the contact surface between the metal housing and the molded material cured product due to vibration and internal / external heat during long-term operation of the motor.
　本発明に用いる硬化促進剤は、イミダゾール系やリン系等、一般に知られている促進剤が利用できる。しかし、本発明では、硬化時にエポキシ樹脂の自己重合を起こさず、成形材料の保存安定性に優れたリン系の硬化促進剤が特に好ましい。硬化促進剤は、単独或いは二種類以上を用いることができる。 As the curing accelerator used in the present invention, generally known accelerators such as imidazole and phosphorus can be used. However, in the present invention, a phosphorus-based curing accelerator that does not cause self-polymerization of the epoxy resin during curing and is excellent in storage stability of the molding material is particularly preferable. The curing accelerator can be used alone or in combination of two or more.
　具体的には、トリフェニルホスフィン、トリオルトトリルホスフィン、トリメタトリルホスフィン、トリパラトリルホスフィン、トリシクロヘキシルホスフィン、トリターシャリーブチルホスホニウムテトラフェニルボレート、トリターシャリーブチルホスホニウムテトラフェニルボレート、トリターシャリーブチルホスホニウムテトラフェニルボレート、トリターシャリーブチルホスホニウムテトラフェニルボレート、トリターシャリーブチルホスホニウムテトラフェニルボレート、トリターシャリーブチルホスホニウムテトラフェニルボレート、トリターシャリーブチルホスホニウムテトラフェニルボレート、トリターシャリーブチルホスホニウムテトラフェニルボレート、トリターシャリーブチルホスホニウムテトラフェニルボレート、トリターシャリーブチルホスホニウムテトラフェニルボレート、トリターシャリーブチルホスホニウムテトラフェニルボレート、トリターシャリーブチルホスホニウムテトラフェニルボレート等がある。 Specifically, triphenylphosphine, triorthotolylphosphine, trimetatolylphosphine, triparatolylphosphine, tricyclohexylphosphine, tritertiary butylphosphonium tetraphenylborate, tritertiarybutylphosphonium tetraphenylborate, tritertiarybutylphosphonium Tetraphenylborate, tritertiary butylphosphonium tetraphenylborate, tritertiary butylphosphonium tetraphenylborate, tritertiary butylphosphonium tetraphenylborate, tritertiarybutylphosphonium tetraphenylborate, tritertiarybutylphosphonium tetraphenylborate, triter Tertiary butylphosphonium tetraphenyl volley There tri tertiary butyl phosphonium tetraphenylborate, tri-tert-butyl phosphonium tetraphenylborate, tri-tert-butyl phosphonium tetraphenylborate and the like.
　本発明には、目的に応じて、上記成形材料に着色剤、離型剤、応力緩和剤、カップリング剤又は難燃剤を添加することができる。 In the present invention, a coloring agent, a release agent, a stress relaxation agent, a coupling agent, or a flame retardant can be added to the molding material depending on the purpose.
　着色剤は、特に制限はないが、カーボンブラック、酸化チタン、フタロシアニン、クロームグリーン、硫酸鉛、酸化クロム、コバルトグリーンなどが挙げられる。着色剤は、単独或いは二種類以上を用いることができる。 The colorant is not particularly limited, and examples thereof include carbon black, titanium oxide, phthalocyanine, chrome green, lead sulfate, chromium oxide, and cobalt green. The colorant can be used alone or in combination of two or more.
　離型剤は、パラフィンワックス、マイクロワックス、ポリエチレンワックス等の炭化水素系離型剤、ラウリン酸、ミリスチン酸、パルミチン酸、ステアリン酸、アラキジン酸等の高級脂肪酸系離型剤、ステアリルアミド、パルミチンアミド等の高級脂肪族アミド系離型剤、カルナバワックス、モンタン酸ワックス等の天然ワックス系離型剤があげられる。離型剤は、単独或いは二種類以上を用いることができる。 Release agents include hydrocarbon release agents such as paraffin wax, microwax, and polyethylene wax, higher fatty acid release agents such as lauric acid, myristic acid, palmitic acid, stearic acid, and arachidic acid, stearylamide, and palmitic amide. And higher aliphatic amide release agents, and natural wax release agents such as carnauba wax and montanic acid wax. The release agent can be used alone or in combination of two or more.
　カップリング剤としては、具体的に、３－グリシドキシプロピルトリメトキシシラン、３－グリシドキシプロピルメチルジメトキシシシラン、３－グリシドキシプロピルトリエトキシシラン、２－（３，４－エポキシシクロヘキシル）エチルトリメトキシシラン、３－メタクリロキシプロピルトリエトキシシラン、Ｎ－フェニル－３－アミノプロピルトリメトキシシラン、３－トリエトキシシリル－Ｎ－（１，３－ジメチル－ブチリデン）プロピルアミン、Ｎ－２－（アミノエチル）－３－アミノプロピルトリエトキシシラン、３－イソシアネートプロピルトリエトキシシラン、ビス（トリエトキシシリルプロピル）テトラスルフィド、３－メルカプトプロピルトリメトキシシラン、３－ウレイドプロピルトリエトキシシラン、３－トリメトキシシリルプロピルコハク酸無水物、ｐ－スチリルトリメトキシシラン、３－メタクリロキシプロピルメチルジメトキシシラン、３－メタクリロキシプロピルメチルジエトキシシラン、３－メタクリロキシプロピルメチルジエトキシシラン、ビニルトリエトキシシラン、ビニルトリメトキシシラン、ビニルトリメトキシシラン、チタンテトラノルマルブトキシド、チタンテトラ－２－エチルヘキソキシド、チタンラクテート、チタンジイソプロポキシ、ビス（トリエタノールアミネート）、チタンラクテートアンモニウム塩等がある。カップリング剤は、単独あるいは二種類以上用いることができる。 Specific examples of the coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl). ) Ethyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-2 -(Aminoethyl) -3-aminopropyltriethoxysilane, 3-isocyanatopropyltriethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3- Trime Xylylpropyl succinic anhydride, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, vinyltriethoxysilane, vinyl Examples include trimethoxysilane, vinyltrimethoxysilane, titanium tetranormal butoxide, titanium tetra-2-ethylhexoxide, titanium lactate, titanium diisopropoxy, bis (triethanolamate), and titanium lactate ammonium salt. The coupling agent can be used alone or in combination of two or more.
　難燃剤は、難燃化のメカニズムにより、以下に示すいくつかの組み合わせがあるが、本発明では、特に限定されない。 The flame retardant has several combinations shown below depending on the mechanism of flame retardancy, but is not particularly limited in the present invention.
　（酸化アンチモンその他の金属化合物）
　酸化アンチモンには、三酸化アンチモン及び五酸化アンチモンがある。その他の金属化合物には、硫酸亜鉛、ホウ酸亜鉛、酸化モリブデン、錫酸亜鉛、酸化錫等がある。 (Antimony oxide and other metal compounds)
Antimony oxide includes antimony trioxide and antimony pentoxide. Other metal compounds include zinc sulfate, zinc borate, molybdenum oxide, zinc stannate, tin oxide and the like.
　（リン化合物及びハロゲン化合物）
　リン化合物には、トリフェニルホスフェートなどの芳香族のリン酸エステル、赤リンなど、ハロゲンを含むリン酸エステル等がある。 (Phosphorus compounds and halogen compounds)
Examples of the phosphorus compound include aromatic phosphates such as triphenyl phosphate, phosphates containing halogen such as red phosphorus, and the like.
　ハロゲン化合物には、テトラブロモビスフェノールＡ、デカブロモジフェニルエーテル、オクタブロモジフェニルエーテル、ペンタブロモジフェニルエーテル、テトラブロモジフェニルエーテル、ヘキサブロモシクロドデカン、トリブロモフェノール、ビス（トリブロモフェノキシエタン）、ビス（ペンタブロモジフェニルエタン）、ヘキサブロモベンゼンポリブロモビフェニル等がある。 Halogen compounds include tetrabromobisphenol A, decabromodiphenyl ether, octabromodiphenyl ether, pentabromodiphenyl ether, tetrabromodiphenyl ether, hexabromocyclododecane, tribromophenol, bis (tribromophenoxyethane), bis (pentabromodiphenylethane) And hexabromobenzene polybromobiphenyl.
　（窒素含有化合物）
　窒素含有化合物には、例えばメラミンシアヌレート、アゾジカルボンアミド、ジニトロソペンタメチレンテトラミンや、ビステトラゾール・ジアンモニウム、ビステトラゾール・ピペラジンなどのテトラゾール系化合物などが挙げられる。難燃性又は分解開始温度の観点からは、メラミンシアヌレート、アゾジカルボンアミド、テトラゾール系化合物が好ましく、メラミンシアヌレート、テトラゾール系化合物がより好ましい。ただし、窒素含有化合物は、これらの例に特に限定されない。 (Nitrogen-containing compounds)
Examples of the nitrogen-containing compound include melamine cyanurate, azodicarbonamide, dinitrosopentamethylenetetramine, and tetrazole compounds such as bistetrazole / diammonium and bistetrazole / piperazine. From the viewpoint of flame retardancy or decomposition start temperature, melamine cyanurate, azodicarbonamide, and tetrazole compounds are preferable, and melamine cyanurate and tetrazole compounds are more preferable. However, the nitrogen-containing compound is not particularly limited to these examples.
　（マンガン化合物及び亜鉛化合物）
　マンガン化合物には、酸化マンガン、酢酸マンガン、硫酸マンガン等がある。亜鉛化合物には、酸化亜鉛、酢酸亜鉛、硫酸亜鉛等がある。 (Manganese compounds and zinc compounds)
Manganese compounds include manganese oxide, manganese acetate, manganese sulfate and the like. Zinc compounds include zinc oxide, zinc acetate, zinc sulfate and the like.
　（金属水酸化物及び難燃助剤）
　金属水酸化物には、水酸化アルミニウム、水酸化マグネシウム等がある。難燃助剤には、硝酸銅、硝酸鉄、シリコーン化合物、硼酸亜鉛等がある。 (Metal hydroxide and flame retardant aid)
Examples of the metal hydroxide include aluminum hydroxide and magnesium hydroxide. Flame retardant aids include copper nitrate, iron nitrate, silicone compounds, zinc borate and the like.
　本発明においては、単独または二種類以上の難燃剤を用いることができる。難燃剤は、用いなくてもよい。 In the present invention, one or more flame retardants can be used. A flame retardant may not be used.
　次に、実際の作製方法及び測定方法について具体的に説明する。ただし、本発明は、これらの方法によって限定されるものではない。 Next, the actual production method and measurement method will be specifically described. However, the present invention is not limited by these methods.
　（１）成形材料の作製
　本発明のエポキシ樹脂成形材料を調製するには、エポキシ樹脂、硬化剤、硬化促進剤、無機充填剤、可とう性添加剤、カップリング剤、着色材及び離型剤を、各成分を評量した後、ポリ袋の中で軽く混合する。必要に応じて、難燃剤等も混合する。その後、熱ミキシングロールを用いて混錬して成形材料を作製する。５５ｋＷ用アキシャルギャップ型モータの固定子をトランスファー成形する場合は、混錬を終えた成形材料をタブレット成形機でタブレット化した成形材料を用いた。固定子金型を挟んだトランスファープレス機のポットにタブレットを投入し、加熱成形して、５５ｋＷ用アキシャルギャップ型モータの固定子を得た。 (1) Production of molding material In order to prepare the epoxy resin molding material of the present invention, an epoxy resin, a curing agent, a curing accelerator, an inorganic filler, a flexible additive, a coupling agent, a coloring material, and a release agent are used. After weighing each component, lightly mix in a plastic bag. If necessary, mix flame retardants. Thereafter, kneading is performed using a heat mixing roll to produce a molding material. When the stator of the 55 kW axial gap type motor was transfer molded, a molding material obtained by tableting the kneaded molding material with a tablet molding machine was used. A tablet was put into a pot of a transfer press machine that sandwiched the stator mold, and was heat-molded to obtain a 55 kW axial gap motor stator.
　各素材を所定の割合で配合し、ポリ袋の中で軽く混合した。その後、素材を８インチミキシングロール（朋来製作所製、ロールサイズ：２００ｍｍφ×５００ｍｍ）を用いて混錬して成形材料を作製した。前ロール６５℃、後ロール５５℃とし、混錬時間はロールに各素材が巻付いた後１５～２０分とした。混錬を終えた成形材料は、粉砕機（朋来製作所製、ＤＢ－３２００型）で粉砕した。また、トランスファー成形で物性評価用試験片やアキシャルギャップ型モータの固定子を成形する時には、タブレット成形機（藤和精機製、ＰＨ２０ＡＳ型）で成形されたタブレットを用いた。このタブレットを、高周波プレヒータ（富士電波工機製、ＦＤＰ－３２３型）を用いて７５℃まで予備加熱し、金型を挟んだトランスファープレス機（藤和精機社製）のポットに投入し、成形した。成形条件は、温度１８０℃で、時間３．０分、成形圧力７．５ＭＰａである。後硬化はしなかった。 Each material was blended at a predetermined ratio and lightly mixed in a plastic bag. Thereafter, the raw material was kneaded using an 8-inch mixing roll (manufactured by Torai Seisakusho, roll size: 200 mmφ × 500 mm) to produce a molding material. The front roll was 65 ° C. and the rear roll was 55 ° C. The kneading time was 15 to 20 minutes after each material was wound around the roll. After the kneading, the molding material was pulverized with a pulverizer (DB-3200, manufactured by Torai Seisakusho). Further, when molding a physical property evaluation test piece or an axial gap type motor stator by transfer molding, a tablet molded by a tablet molding machine (PH20AS model, manufactured by Fujiwa Seiki Co., Ltd.) was used. This tablet was preheated to 75 ° C. using a high-frequency preheater (FDP-323 type, manufactured by Fuji Electric Koki Co., Ltd.), put into a pot of a transfer press machine (manufactured by Fujiwa Seiki Co., Ltd.) sandwiching the mold, and molded. The molding conditions are a temperature of 180 ° C., a time of 3.0 minutes, and a molding pressure of 7.5 MPa. There was no post cure.
　（各物性値の測定法）
　（１）Ｍｗの測定
　エポキシ樹脂や硬化剤などの重量平均分子量Ｍｗ（ポリスチレン換算値）は、検出器としてＬ－３３００（ＲＩ）型（日立化成製）を用いて測定した。測定条件は、次のとおりである。 (Measurement method of each physical property value)
(1) Measurement of Mw The weight average molecular weight Mw (polystyrene conversion value) of an epoxy resin or a curing agent was measured using an L-3300 (RI) type (manufactured by Hitachi Chemical) as a detector. The measurement conditions are as follows.
　カラム：Ｇｅｌｐａｋ　ＧＬ－Ｒ４４０＋Ｒ４５０＋Ｒ４００Ｍ、カラム温度：３０℃、流量：１．５ｍｌ／分、溶離液：テトラヒドロフラン。 Column: Gelpak GL-R440 + R450 + R400M, column temperature: 30 ° C., flow rate: 1.5 ml / min, eluent: tetrahydrofuran.
　（２）曲げ強度
　曲げ強さは、トランスファー成形により作製したダンベル形状の試験片（サイズ：１２．７ｍｍ×１２７ｍｍ×５ｍｍｔ）を用い、オートグラフ万能試験機（島津製、ＡＧ－Ｘ型１００ｋＮ）を用いて測定した。曲げ速度２ｍｍ／分、支点間距離８０ｍｍ、測定温度：室温で測定した。 (2) Bending strength The bending strength was determined by using an autograph universal testing machine (manufactured by Shimadzu, AG-X type 100 kN) using a dumbbell-shaped test piece (size: 12.7 mm × 127 mm × 5 mmt) produced by transfer molding. And measured. The measurement was performed at a bending speed of 2 mm / min, a fulcrum distance of 80 mm, and a measurement temperature: room temperature.
　（３）熱膨張係数
　熱膨張係数は、トランスファー成形により作製したφ１０ｍｍ×１００ｍｍの丸棒を長さ約１０ｍｍに切断し、昇温速度２℃／分でＡＳＴＭ－Ｄ６９６に準じて、熱機械的分析装置（ＴＭＡ：アルバック製、ＴＭ－９３００型）で伸びを測定して１００～１５０℃範囲の熱膨張係数を求めた。 (3) Coefficient of thermal expansion Coefficient of thermal expansion is determined by thermomechanical analysis according to ASTM-D696 at a heating rate of 2 ° C / min after cutting a round bar of φ10mm x 100mm produced by transfer molding into a length of about 10mm. The elongation was measured with an apparatus (TMA: UL-9, TM-9300 type) to obtain a coefficient of thermal expansion in the range of 100 to 150 ° C.
　（４）破壊靱性値
　ＡＳＴＭＤ５０４５－９１に従い、３点曲げ試験片にカミソリ刃を用いて初期亀裂を生成し、圧縮荷重を加えて亀裂が進展して破断した際の荷重から破壊靱性値を算出した。試験は、室温にて実施した。クロスヘッド速度は１．０ｍｍ／分とした。これらは万能引張試験機を用いて測定した。 (4) Fracture toughness value In accordance with ASTM D5045-91, an initial crack was generated using a razor blade on a three-point bending test piece, and the fracture toughness value was calculated from the load when the crack developed and fractured by applying a compressive load. . The test was conducted at room temperature. The crosshead speed was 1.0 mm / min. These were measured using a universal tensile tester.
　（５）流動性
　成形材料の流動性は、ＳＰＩ－ＥＭＭＩ－１－６６に準じて、スパイラスフロー測定用金型を用いてトランスファー成形を行い、スパイラル状の成形物を作製し、その流動長さを測定することにより評価した。５５ｋＷ用アキシャルギャップ型モータの固定子に適用するには、流動長さが２５インチ以上の値であることが好ましい。 (5) Flowability The flowability of the molding material is determined according to SPI-EMMI-1-66 by transfer molding using a spiral flow measurement mold to produce a spiral molded product. Was evaluated by measuring. In order to be applied to the stator of a 55 kW axial gap type motor, the flow length is preferably a value of 25 inches or more.
　（６）せん断強度
　アキシャルギャップ型モータの固定子のハウジングのアルミニウムと同じ材質のアルミニウム板（材質ＡＤＬ１２、表面粗さ４μｍ）の上に、下部が直径５ｍｍφ、上部が直径４ｍｍφ、高さ３ｍｍの円柱成形品をトランスファー成形（１８０℃／３分、４．５ＭＰａ）により作製し、せん断強度測定試験片とした。これを万能テスタ（デイジ社製、ＰＣ２４００型）の上に固定し、せん断冶具下部がアルミニウム基板上１００μｍを通過するようにセットし、せん断刃を移動（速度：２ｍｍ／分）し、せん断強さ（ＭＰａ）を測定した。 (6) Shear strength On an aluminum plate (material ADL12, surface roughness 4 μm) of the same material as the aluminum of the stator gap of the axial gap motor, a cylinder with a lower diameter of 5 mmφ, an upper part of 4 mmφ and a height of 3 mm A molded product was produced by transfer molding (180 ° C./3 minutes, 4.5 MPa), and used as a test piece for measuring shear strength. This is fixed on a universal tester (manufactured by Daisy, PC2400 type), set so that the lower part of the shear jig passes 100 μm on the aluminum substrate, the shear blade is moved (speed: 2 mm / min), and the shear strength (MPa) was measured.
　（７）耐熱温度クラス
　絶縁材料は、ＪＩＳ　Ｃ４００３（日本工業規格）により、耐熱温度の指標である耐熱温度クラスが決められており、Ｙ種（９０℃）、Ａ種（１０５℃）、Ｅ種（１２０℃）、Ｂ種（１３０℃）、Ｆ種（１５５℃）、Ｈ種（１８０℃）、２００℃、２２０℃、２４０℃に分類される。ここで、かっこ内の温度は最高許容温度である。 (7) Heat-resistant temperature class Insulating materials are determined in accordance with JIS C4003 (Japanese Industrial Standards) as a heat-resistant temperature class, which is an index of heat-resistant temperature. Y type (90 ° C), A type (105 ° C), E type (120 ° C.), B type (130 ° C.), F type (155 ° C.), H type (180 ° C.), 200 ° C., 220 ° C., and 240 ° C. Here, the temperature in parentheses is the maximum allowable temperature.
　一般に、絶縁材料は高温に長時間さらされると、物性が低下する。物性が初期値に対して一定の割合に低下するまでの時間（Ｌ）及び絶対温度（Ｔ）は、次のアレニウスの式に従う。 Generally, when an insulating material is exposed to a high temperature for a long time, its physical properties deteriorate. The time (L) and the absolute temperature (T) until the physical properties are reduced to a certain ratio with respect to the initial value follow the following Arrhenius equation.
　Ｌｏｇ（Ｌ）＝ａ＋ｂ／Ｔ
　ここで、Ｌｏｇは、自然対数を表すものであり、Ｌは寿命時間であり、Ｔは絶対温度であり、ａ及びｂは定数である。 Log (L) = a + b / T
Here, Log represents a natural logarithm, L is a lifetime, T is an absolute temperature, and a and b are constants.
　時間Ｌをその絶縁材料の寿命時間とすると、対数の寿命時間と１／Ｔの温度とは直線関係にあり、高温ほど寿命が短い。したがって、成形材料の熱劣化の加速試験を行い、各加速温度での寿命時間を求め、より低温での寿命予測を行った。成形材料を熱劣化させる加速条件は、化学的劣化速度が１０℃上昇するごとに二倍になるという経験則から決定した。 Suppose that the time L is the lifetime of the insulating material, the logarithmic lifetime and the temperature of 1 / T are in a linear relationship, and the lifetime is shorter at higher temperatures. Therefore, an accelerated test for thermal deterioration of the molding material was performed, the lifetime at each acceleration temperature was obtained, and the lifetime at a lower temperature was predicted. The acceleration condition for thermally degrading the molding material was determined from an empirical rule that the chemical degradation rate doubles every 10 ° C. increase.
　本発明のエポキシ樹脂成形材料の耐熱温度クラスは、Ｆ種（１５５℃／２００００ｈ）の寿命をクリアすると仮定して加速試験を行った。 The heat resistance temperature class of the epoxy resin molding material of the present invention was subjected to an acceleration test on the assumption that the life of Class F (155 ° C./20000h) was cleared.
　モータ寿命の原因は、故障しやすいコイル部を構成する絶縁材料の劣化である。このことから、成形材料の劣化要因と考えられる－１０％熱重量減少率を寿命時間として各温度から耐熱温度クラスを求めた。 The cause of motor life is the deterioration of the insulating material that constitutes the coil part that is prone to failure. From this, the heat-resistant temperature class was determined from each temperature using the -10% thermal weight loss rate, which is considered to be a cause of deterioration of the molding material, as the lifetime.
　実施例で用いた材料は、次のとおりである。 The materials used in the examples are as follows.
　エポキシ樹脂１：ｏ－クレゾールノボラック型エポキシ樹脂（住友化学製、商品名：ＥＳＣＮ－１９０、Ｍｗ１１００、エポキシ当量１９５ｇ／ｅｑ）
　エポキシ樹脂２：ｏ－クレゾールノボラック型エポキシ樹脂（新日鐵住金化学製、商品名：ＹＤＣＮ－７００－３、Ｍｗ１５００、エポキシ当量１９５ｇ／ｅｑ）
　エポキシ樹脂３：ｏ－クレゾールノボラック型エポキシ樹脂（新日鐵住金化学製、商品名：ＹＤＣＮ－７００－１０、Ｍｗ２２００、エポキシ当量２０６ｇ／ｅｑ）
　エポキシ樹脂４：ｏ－クレゾールノボラックエポキシ樹脂（ＤＩＣ製、商品名：エピクロンＮ－６６０、Ｍｗ６８０、エポキシ当量２１０ｇ／ｅｑ）
　硬化剤１：ノボラック型フェノール樹脂（明和化成製、商品名：Ｈ－１、Ｍｗ１１００、水酸基当量１０６ｇ／ｅｑ）
　硬化剤２：ノボラック型フェノール樹脂（明和化成製、商品名：Ｈ－４、Ｍｗ６７０、水酸基当量１０２ｇ／ｅｑ）
　硬化剤３：ノボラック型フェノール樹脂（明和化成製、商品名：ＨＦ－４Ｍ、Ｍｗ１３００、水酸基当量１０７ｇ／ｅｑ）
　無機充填剤１：破砕シリカ（龍森製、商品名：クリスタライトＸＪ－７、平均粒径４．９μｍ）
　無機充填剤２：日東紡製、商品名：チョップドストランド、ＣＳ６Ｅ－２２７、長さ６ｍｍ、直径１０μｍ
　無機充填剤３：平均粒径の異なる３種類の球状シリカ充填剤の混合物（組成は、表１に示す。） Epoxy resin 1: o-cresol novolac type epoxy resin (manufactured by Sumitomo Chemical Co., Ltd., trade name: ESCN-190, Mw 1100, epoxy equivalent 195 g / eq)
Epoxy resin 2: o-cresol novolac type epoxy resin (manufactured by Nippon Steel & Sumikin Chemical, trade name: YDCN-700-3, Mw 1500, epoxy equivalent 195 g / eq)
Epoxy resin 3: o-cresol novolac type epoxy resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., trade name: YDCN-700-10, Mw2200, epoxy equivalent 206 g / eq)
Epoxy resin 4: o-cresol novolac epoxy resin (manufactured by DIC, trade name: Epicron N-660, Mw 680, epoxy equivalent 210 g / eq)
Curing agent 1: Novolac type phenol resin (Maywa Kasei Co., Ltd., trade name: H-1, Mw 1100, hydroxyl group equivalent 106 g / eq)
Curing agent 2: Novolac type phenol resin (Maywa Kasei Co., Ltd., trade name: H-4, Mw 670, hydroxyl group equivalent 102 g / eq)
Curing agent 3: Novolac type phenolic resin (product name: HF-4M, Mw1300, hydroxyl group equivalent 107 g / eq, manufactured by Meiwa Kasei)
Inorganic filler 1: Crushed silica (manufactured by Tatsumori, trade name: Crystallite XJ-7, average particle size 4.9 μm)
Inorganic filler 2: manufactured by Nittobo, trade name: chopped strand, CS6E-227, length 6 mm, diameter 10 μm
Inorganic filler 3: A mixture of three types of spherical silica fillers having different average particle diameters (the composition is shown in Table 1).
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　硬化促進剤：リン系硬化促進剤（北興化学製、商品名：ＴＰＰ－ｋ）
　可とう性付与剤１：コアシェル型ゴム粒子（ローム＆ハース製、商品名：ＢＴＡ－７３１Ｊ、一次粒子径１００～６００ｎｍ）
　可とう性付与剤２：ＮＢＲゴム粒子（三洋貿易製、商品名：ＶＰ－５０１、一次粒径５０～１００ｎｍ）
　カップリング剤（信越化学製、商品名：ＫＢＭ４０３）
　離型剤（クライアントジャパン製、商品名：リコワックスＥパウダー）
　（実施例１～４及び比較例１～４）
　表２は、実施例及び比較例のエポキシ樹脂組成物の組成を示したものである。 Curing accelerator: Phosphorus curing accelerator (made by Hokuko Chemical, trade name: TPP-k)
Flexibility imparting agent 1: Core-shell type rubber particles (Rohm & Haas, trade name: BTA-731J, primary particle size 100-600 nm)
Flexibility imparting agent 2: NBR rubber particles (manufactured by Sanyo Trading Co., Ltd., trade name: VP-501, primary particle size 50-100 nm)
Coupling agent (trade name: KBM403, manufactured by Shin-Etsu Chemical)
Mold release agent (manufactured by Client Japan, trade name: Ricowax E powder)
(Examples 1 to 4 and Comparative Examples 1 to 4)
Table 2 shows the compositions of the epoxy resin compositions of Examples and Comparative Examples.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　本表に示す実施例及び比較例はいずれも、エポキシ樹脂、硬化剤等の樹脂分に対して無機充填剤を７８重量％含むものである。 All examples and comparative examples shown in this table contain 78% by weight of an inorganic filler with respect to the resin content such as epoxy resin and curing agent.
　実施例１のエポキシ樹脂組成物は、エポキシ樹脂１、硬化剤１、無機充填剤１、無機充填剤２、硬化促進剤、可とう性付与剤１、可とう性付与剤２、カップリング剤及び離型剤を含む。 The epoxy resin composition of Example 1 includes an epoxy resin 1, a curing agent 1, an inorganic filler 1, an inorganic filler 2, a curing accelerator, a flexibility imparting agent 1, a flexibility imparting agent 2, a coupling agent and Contains a release agent.
　実施例２のエポキシ樹脂組成物は、エポキシ樹脂２及び硬化剤３を用いた点以外は、実施例１と同じである。 The epoxy resin composition of Example 2 is the same as Example 1 except that the epoxy resin 2 and the curing agent 3 are used.
　実施例３のエポキシ樹脂組成物は、硬化剤３を用いた点、及び無機充填剤１の配合を増やし、無機充填剤２を減らした点以外は、実施例１と同じである。 Example 3 The epoxy resin composition of Example 3 is the same as Example 1 except that the curing agent 3 is used and the inorganic filler 1 is added more and the inorganic filler 2 is reduced.
　実施例４のエポキシ樹脂組成物は、エポキシ樹脂２を用いた点、及び硬化剤１をわずかに減らした点以外は、実施例１と同じである。 The epoxy resin composition of Example 4 is the same as Example 1 except that the epoxy resin 2 is used and the curing agent 1 is slightly reduced.
　比較例１のエポキシ樹脂組成物は、エポキシ樹脂３を用いた点、並びに硬化剤１、可とう性付与剤１及び可とう性付与剤２の量を微調整した点以外は、実施例１と同じとした。 The epoxy resin composition of Comparative Example 1 is the same as in Example 1 except that the epoxy resin 3 was used and the amounts of the curing agent 1, the flexibility imparting agent 1 and the flexibility imparting agent 2 were finely adjusted. Same as above.
　比較例２のエポキシ樹脂組成物は、エポキシ樹脂４及び硬化剤２を用いた点以外は、実施例１と同じとした。 The epoxy resin composition of Comparative Example 2 was the same as Example 1 except that the epoxy resin 4 and the curing agent 2 were used.
　比較例３のエポキシ樹脂組成物は、実施例１及び２と同様にエポキシ樹脂１を用い、比較例２と同様に硬化剤２を用い、無機充填剤として平均粒径の異なる３種類からなる球状シリカ（無機充填剤３）を用いた。 The epoxy resin composition of Comparative Example 3 uses the epoxy resin 1 as in Examples 1 and 2, uses the curing agent 2 as in Comparative Example 2, and has three types of spherical particles having different average particle diameters as inorganic fillers. Silica (inorganic filler 3) was used.
　比較例４のエポキシ樹脂組成物は、エポキシ樹脂２及び硬化剤３を用いた点、並びに可とう性付与剤を用いない点以外は、実施例１と同じとした。 The epoxy resin composition of Comparative Example 4 was the same as Example 1 except that the epoxy resin 2 and the curing agent 3 were used, and the flexibility imparting agent was not used.
　表３は、実施例及び比較例の特性を示したものである。 Table 3 shows the characteristics of Examples and Comparative Examples.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　本表に示すとおり、実施例１のスパイラルフロー値は２５インチ、せん断強度は６．８ＭＰａ、耐熱温度クラスは１５６℃、熱膨張係数は２６ｐｐｍ／℃、破壊靭性値は３．１ＭＰａ√ｍである。したがって、実施例１は、無機充填剤に安価な破砕フィラを主成分に用いているにもかかわらず、各特性値のバランスがよいことがわかる。また、実施例２～４も、実施例１と同程度の特性を有し、バランスがよいことがわかる。 As shown in this table, the spiral flow value of Example 1 is 25 inches, the shear strength is 6.8 MPa, the heat resistant temperature class is 156 ° C., the thermal expansion coefficient is 26 ppm / ° C., and the fracture toughness value is 3.1 MPa√m. . Therefore, it can be seen that Example 1 has a good balance of the characteristic values despite using an inexpensive crushed filler as the main component for the inorganic filler. It can also be seen that Examples 2 to 4 have the same characteristics as Example 1 and are well balanced.
　比較例１のスパイラルフロー値は、１２インチと実施例１～４に比べて低下した。他の物性は実施例とほぼ同等であった。 The spiral flow value of Comparative Example 1 was 12 inches, which was lower than that of Examples 1 to 4. Other physical properties were almost the same as in the examples.
　比較例２のスパイラルフロー値は、４２インチと優れた値を示すが、破壊靭性値が２．３ＭＰａ√ｍと大きく低下した。 The spiral flow value of Comparative Example 2 was an excellent value of 42 inches, but the fracture toughness value was greatly reduced to 2.3 MPa√m.
　比較例３のスパイラルフロー値は、７６インチと優れた値を示すが、破壊靭性値が２．０ＭＰａ√ｍと大きく低下した。 The spiral flow value of Comparative Example 3 shows an excellent value of 76 inches, but the fracture toughness value was greatly reduced to 2.0 MPa√m.
　比較例４のスパイラルフロー値は、７０インチと優れた値を示すが、破壊靭性値が１．２ＭＰａ√ｍと大きく低下した。 The spiral flow value of Comparative Example 4 shows an excellent value of 70 inches, but the fracture toughness value was greatly reduced to 1.2 MPa√m.
　以上のように、本発明の実施例は、比較例に比べ、無機充填剤に安価な破砕フィラを主成分に用いているにかかわらず、スパイラルフロー値、せん断強度値、耐熱温度クラス、熱膨張係数及び破壊靭性値の各特性値のバランスが優れていることが分かる。 As described above, the examples of the present invention have a spiral flow value, a shear strength value, a heat resistant temperature class, a thermal expansion, regardless of whether an inexpensive crushed filler is used as a main component compared with the comparative example. It turns out that the balance of each characteristic value of a coefficient and a fracture toughness value is excellent.
　したがって、本発明のエポキシ樹脂組成物は、アキシャルギャップ型モータをはじめとして各種製品の絶縁材料や構造材料に用いることができる。 Therefore, the epoxy resin composition of the present invention can be used for insulating materials and structural materials of various products including an axial gap type motor.
　次に、本発明のエポキシ樹脂組成物をモータに適用した場合の効果について説明する。 Next, the effect when the epoxy resin composition of the present invention is applied to a motor will be described.
　図１は、本発明のエポキシ樹脂組成物を適用したアキシャルギャップ型モータを分解して内部構造を模式的に示したものである。 FIG. 1 schematically shows the internal structure of an axial gap motor to which the epoxy resin composition of the present invention is applied.
　本図において、アキシャルギャップ型モータは、二個の回転子２、３の間に固定子１を配置した構成を有している。固定子１及び回転子２、３は、アルミニウム製のハウジング４の中に収容されている。破線で示す範囲は、固定子１及び回転子２、３のそれぞれに含まれる部材を表している。固定子１は、複数の鉄心５が回転子２、３の回転軸に対して放射状に配置されている。これらの複数の鉄心５は、本発明のエポキシ樹脂組成物を硬化したエポキシ樹脂硬化物でハウジング４に固定されている。 In this figure, the axial gap type motor has a configuration in which a stator 1 is arranged between two rotors 2 and 3. The stator 1 and the rotors 2 and 3 are accommodated in an aluminum housing 4. A range indicated by a broken line represents a member included in each of the stator 1 and the rotors 2 and 3. In the stator 1, a plurality of iron cores 5 are arranged radially with respect to the rotation axes of the rotors 2 and 3. The plurality of iron cores 5 are fixed to the housing 4 with a cured epoxy resin obtained by curing the epoxy resin composition of the present invention.
　図２は、図１のアキシャルギャップ型モータに用いた固定子を固定した状態を示したものであって、アキシャルギャップ型モータを中心軸付近で二分割した一方の部分を示したものである。 FIG. 2 shows a state in which the stator used in the axial gap type motor of FIG. 1 is fixed, and shows one part of the axial gap type motor divided into two near the central axis.
　本図においては、固定子１は、鉄心５及び鉄心５の周囲に巻き回されたコイル等で構成されている。固定子１の構成要素の隙間には、エポキシ樹脂硬化物６が充填されている。また、固定子１は、ハウジング４の内壁に接着により固定されている。回転子２、３は、シャフト７（回転軸）に固定され、回転子２、３及びシャフト７は、ベアリング１０を有する軸受８、９によって固定子１及びハウジング４に対して回転可能に支持されている。 In this figure, the stator 1 is composed of an iron core 5 and a coil wound around the iron core 5. A gap between the constituent elements of the stator 1 is filled with a cured epoxy resin 6. The stator 1 is fixed to the inner wall of the housing 4 by adhesion. The rotors 2 and 3 are fixed to a shaft 7 (rotating shaft), and the rotors 2 and 3 and the shaft 7 are rotatably supported with respect to the stator 1 and the housing 4 by bearings 8 and 9 having bearings 10. ing.
　固定子１は、モータ駆動時の温度上昇や振動によって、熱応力や振動に起因する応力が発生するため、エポキシ樹脂硬化物６の割れやクラック又はエポキシ樹脂硬化物６とハウジング４との界面における剥離が発生しやすい。エポキシ樹脂硬化物６の破壊は、複数の鉄心間での相対位置や固定子１の軸ずれを引き起こし、モータの性能を著しく低下させる。 Since the stator 1 generates stress due to thermal stress or vibration due to temperature rise or vibration when the motor is driven, the stator 1 is cracked or cracked in the cured epoxy resin 6 or at the interface between the cured epoxy resin 6 and the housing 4. Peeling easily occurs. The destruction of the cured epoxy resin 6 causes a relative position between the plurality of iron cores and an axial deviation of the stator 1, and significantly reduces the performance of the motor.
　しかしながら、本発明のエポキシ樹脂組成物を用いて作製したエポキシ樹脂硬化物６は、耐熱温度クラスが高く、熱膨張係数がアルミニウムと同等程度であること、及びせん断強度や破壊靱性値が大きいことから、樹脂クラックが発生しにくい。そのため、固定子１の信頼性は向上し、信頼性の高いモータを得ることができる。 However, the cured epoxy resin 6 produced using the epoxy resin composition of the present invention has a high heat resistant temperature class, a thermal expansion coefficient comparable to that of aluminum, and a large shear strength and fracture toughness value. Resin cracks are less likely to occur. Therefore, the reliability of the stator 1 is improved, and a highly reliable motor can be obtained.
　さらに、硬化時間１８０℃／３分のトランスファー成形を用いることにより、硬化時間を大幅に短縮させることができ、生産性が向上し、エポキシ樹脂硬化物６とハウジング４との界面における接着性を大幅に改善することができる。 Furthermore, by using transfer molding with a curing time of 180 ° C./3 minutes, the curing time can be greatly shortened, productivity is improved, and adhesion at the interface between the cured epoxy resin 6 and the housing 4 is greatly increased. Can be improved.
　本発明によれば、安価な破砕状充填剤並びに重量平均分子量を限定したエポキシ樹脂及び硬化剤を組み合わせることにより、優れた成形性を有するエポキシ樹脂成形材料（エポキシ樹脂組成物）を得ることができる。このエポキシ樹脂成形材料を用いれば、狭空間など複雑な内部構造を有する製品も、容易に、短サイクルで製造することができる。 According to the present invention, an epoxy resin molding material (epoxy resin composition) having excellent moldability can be obtained by combining an inexpensive crushed filler and an epoxy resin and a curing agent with a limited weight average molecular weight. . By using this epoxy resin molding material, a product having a complicated internal structure such as a narrow space can be easily manufactured in a short cycle.
　また、その樹脂硬化物は、耐熱性、機械的強度及び長期信頼性に優れている。このエポキシ樹脂組成物から製造された製品は、安価であり、アキシャルギャップ型モータなど複雑な形状の電子・電気部品に適している。 Moreover, the resin cured product is excellent in heat resistance, mechanical strength and long-term reliability. A product manufactured from this epoxy resin composition is inexpensive and suitable for electronic / electrical parts having complicated shapes such as an axial gap type motor.
　本発明は、アキシャルギャップ型モータを用いた自動車や、各種工作機械等の製造に有用である。 The present invention is useful for manufacturing an automobile using an axial gap type motor, various machine tools, and the like.
　１：固定子、２、３：回転子、４：ハウジング、５：鉄心、６：エポキシ樹脂硬化物、７：シャフト、８、９：軸受、１０：ベアリング。 1: Stator, 2, 3: Rotor, 4: Housing, 5: Iron core, 6: Cured epoxy resin, 7: Shaft, 8, 9: Bearing, 10: Bearing.

Claims (11)

  1. 　エポキシ樹脂と、エポキシ樹脂硬化剤と、破砕状無機充填剤とを含み、前記エポキシ樹脂は、クレゾールノボラック型であり、その重量平均分子量が７００～１８００であり、前記エポキシ樹脂硬化剤は、フェノール樹脂であり、その重量平均分子量が７００～１４００であることを特徴とするエポキシ樹脂組成物。 The epoxy resin includes an epoxy resin, an epoxy resin curing agent, and a crushed inorganic filler. The epoxy resin is a cresol novolac type and has a weight average molecular weight of 700 to 1800. The epoxy resin curing agent is a phenol resin. An epoxy resin composition having a weight average molecular weight of 700 to 1400.
  2. 　前記破砕状無機充填剤は、破砕状シリカであり、その平均粒径が２～４０μｍであることを特徴とする請求項１記載のエポキシ樹脂組成物。 2. The epoxy resin composition according to claim 1, wherein the crushed inorganic filler is crushed silica and has an average particle size of 2 to 40 μm.
  3. 　前記破砕状無機充填剤の配合量は６５～９５重量％であることを特徴とする請求項１記載のエポキシ樹脂組成物。 2. The epoxy resin composition according to claim 1, wherein the amount of the crushed inorganic filler is 65 to 95% by weight.
  4. 　前記破砕状無機充填剤は、シリカ、炭酸カルシウム、炭酸マグネシウム、ガラス、タルク、硫酸バリウム、マイカ、アルミナ又は水酸化カルシウムからなることを特徴とする請求項１記載のエポキシ樹脂組成物。 The epoxy resin composition according to claim 1, wherein the crushed inorganic filler comprises silica, calcium carbonate, magnesium carbonate, glass, talc, barium sulfate, mica, alumina, or calcium hydroxide.
  5. 　反応性のモノマ及びオリゴマを含有しないことを特徴とする請求項１記載のエポキシ樹脂組成物。 2. The epoxy resin composition according to claim 1, which does not contain reactive monomers and oligomers.
  6. 　さらに、可とう性付与剤を含むことを特徴とする請求項１記載のエポキシ樹脂組成物。 The epoxy resin composition according to claim 1, further comprising a flexibility imparting agent.
  7. 　請求項１記載のエポキシ樹脂組成物を硬化して作製したエポキシ樹脂硬化物であって、ＪＩＳ　Ｃ４００３により求めた耐熱温度クラスは、Ｆ種（１５５℃）以上であることを特徴とするエポキシ樹脂硬化物。 A cured epoxy resin produced by curing the epoxy resin composition according to claim 1, wherein the heat resistant temperature class determined by JIS C4003 is F type (155 ° C) or higher. object.
  8. 　固定子と、回転子と、これらを収容する金属製のハウジングとを備え、前記固定子は、前記ハウジングに請求項１記載のエポキシ樹脂組成物を硬化したエポキシ樹脂硬化物で固定され、前記エポキシ樹脂硬化物と前記ハウジングとの熱膨張係数の差は、±５ｐｐｍ／℃以内であることを特徴とするモータ。 A stator, a rotor, and a metal housing that accommodates the stator, the stator being fixed to the housing with an epoxy resin cured product obtained by curing the epoxy resin composition according to claim 1, and the epoxy The difference in thermal expansion coefficient between the cured resin and the housing is within ± 5 ppm / ° C.
  9. 　固定子と、回転子と、これらを収容する金属製のハウジングとを備え、前記固定子は、前記ハウジングに請求項１記載のエポキシ樹脂組成物を硬化したエポキシ樹脂硬化物で固定され、前記エポキシ樹脂硬化物の破壊靭性値は、２．８ＭＰａ√ｍ以上であり、前記エポキシ樹脂硬化物と前記ハウジングとの界面のせん断強度は、５．０ＭＰａ以上であることを特徴とするモータ。 A stator, a rotor, and a metal housing that accommodates the stator, the stator being fixed to the housing with an epoxy resin cured product obtained by curing the epoxy resin composition according to claim 1, and the epoxy A motor having a fracture toughness value of a cured resin product of 2.8 MPa√m or more, and a shear strength of an interface between the cured epoxy resin product and the housing of 5.0 MPa or more.
  10. 　固定子と、回転子と、これらを収容する金属製のハウジングとを備え、前記固定子は、前記ハウジングに請求項１記載のエポキシ樹脂組成物を硬化したエポキシ樹脂硬化物で固定され、前記固定子は、箔帯状のアモルファス電磁鋼板を複数層重ねボビンに挿入した構成を有する鉄心と、前記鉄心の外周部に導線を巻き回して形成したコイル部とを含む部材を複数個、前記ハウジングの内部に周方向に並べて配置した構成を有することを特徴とするモータ。 A stator, a rotor, and a metal housing that accommodates the stator, the stator being fixed to the housing with an epoxy resin cured material obtained by curing the epoxy resin composition according to claim 1, and the fixing The child includes a plurality of members including an iron core having a configuration in which a plurality of layers of foil-shaped amorphous electromagnetic steel sheets are inserted into a bobbin and a coil portion formed by winding a conductive wire around the outer periphery of the iron core. A motor having a configuration in which the motors are arranged side by side in the circumferential direction.
  11. 　固定子と、二個の回転子と、これらを収容する金属製のハウジングとを備え、前記固定子は、前記二個の回転子の間に配置され、かつ、前記ハウジングに請求項１記載のエポキシ樹脂組成物を硬化したエポキシ樹脂硬化物で固定されていることを特徴とするアキシャルギャップ型モータ。 The stator according to claim 1, further comprising: a stator, two rotors, and a metal housing that accommodates the stator, the stator being disposed between the two rotors, and the housing. An axial gap type motor characterized by being fixed with a cured epoxy resin obtained by curing an epoxy resin composition.
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JP7302166B2 (en) 2018-12-10 2023-07-04 住友ベークライト株式会社 Resin composition for stator core insulation

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