JP7378438B2 - Liquid thermosetting resin composition, method for curing liquid thermosetting resin composition, stator coil, and rotating electric machine - Google Patents

Description

The present application relates to a liquid thermosetting resin composition, a method of curing the liquid thermosetting resin composition, a stator coil, and a rotating electric machine.

In recent years, with the miniaturization of electrical equipment, efforts have been made to improve the heat resistance of resin materials. Epoxy resin compositions containing epoxy resin and its curing agent as essential components have excellent physical properties such as heat resistance and moisture absorption resistance. It is widely used in coating materials, molding materials, adhesive materials, etc. For example, Patent Document 1 discloses a resin composition in which an allyl group-containing compound containing an epoxy group and a maleimide compound as a heat-resistant component are mixed. Further, Patent Document 2 discloses an epoxy resin composition for semiconductor encapsulation using a bisnaphthalene type tetrafunctional epoxy compound, which is a highly heat-resistant epoxy resin, in combination with a specific phenol resin.

International Patent WO2017/006891 (Paragraph 0015) JP2007-262384A (Paragraph 0009)

General liquid epoxy resins can have low viscosity, but have insufficient heat resistance. In order to enhance heat resistance, attempts have been made to make resins polyfunctional and introduce heat-resistant skeletons, but the use of these increases the viscosity of resin compositions. In order to develop the application of insulating varnish for rotating machines, it is necessary to have the ability to impregnate between the fine windings of rotating electrical machines, but the problem is that it is difficult to obtain a resin composition that has both low viscosity and high heat resistance. was there.

The present application was made to solve the above-mentioned problems, and provides a liquid thermosetting resin composition that has low viscosity, high heat resistance, and high impregnating properties, and a method for curing the liquid thermosetting resin composition. , the purpose is to obtain a stator coil and a rotating electric machine.

（式中のＲ ₁ 、Ｒ ₂ は、Ｒ ₁ ：ＣＯＯＣＨ ₂ ＣＨ＝ＣＨ ₂ 、Ｒ ₂ ：Ｈ、または、Ｒ ₁ ：Ｈ、Ｒ ₂ ：ＣＯＯＣＨ ₂ ＣＨ＝ＣＨ ₂ 、である。）
The liquid thermosetting resin composition disclosed in the present application includes an epoxy compound, a curing agent for curing the epoxy compound, a diluent for diluting the epoxy compound, and a curing accelerator for promoting curing of the epoxy compound. A liquid thermosetting resin composition containing a polymerization initiator that initiates a polymerization reaction of the epoxy compound, wherein the epoxy compound includes a compound represented by the following formula (1). Liquid thermosetting resin composition.

(R ₁ and R ₂ in the formula are R ₁ :COOCH ₂ CH=CH ₂ , R ₂ :H, or R ₁ :H, R ₂ :COOCH ₂ CH=CH ₂ .)

According to the present application, by introducing allyl into the bisnaphthalene type epoxy resin, which is the main component of the epoxy resin composition, it is possible to reduce the viscosity while maintaining high heat resistance, making it possible to use it as an insulating material for rotating machines. .

FIG. 3 is a perspective cross-sectional view of a stator coil according to a second embodiment. FIG. 7 is a diagram schematically showing a main part of a stator of a rotating electrical machine according to Embodiment 3, and is a diagram (cross-sectional view) showing a cross section along the rotation axis. FIG. 3 is a diagram schematically showing a main part of a stator of a rotating electrical machine according to Embodiment 3, and is a diagram (longitudinal cross-sectional view) of a cross section perpendicular to the rotation axis viewed from the direction of arrow A in FIG. 2. FIG.

Embodiment 1.
The liquid thermosetting resin composition according to Embodiment 1 includes a bisnaphthalene type allyl group-containing epoxy compound as an epoxy resin, a curing agent for epoxy resin, a curing accelerator, a reactive diluent, and a polymerization initiator. It contains.

The bisnaphthalene type allyl group-containing epoxy compound is a compound represented by the following formula (1), and has two allyl groups and two epoxy groups.

In formula (1), R ₁ :COOCH ₂ CH=CH ₂ , R ₂ :H, or R ₁ :H, R ₂ :COOCH ₂ CH=CH ₂ .

Since the bisnaphthalene-type allyl group-containing epoxy compound has a bisnaphthalene skeleton, it has the effect of improving the heat resistance of a cured resin product. On the other hand, since it has two allyl groups, the hydrogen bond between the monomers becomes weaker, thereby making it possible to lower the melt viscosity. Furthermore, since it can react with a reactive diluent that polymerizes through a radical reaction, it is possible to control the curing conditions and improve the mechanical properties of the cured product.

The epoxy resin can be used by mixing a bisnaphthalene-type allyl group-containing epoxy compound with one or more other heat-resistant epoxy resins in order to enhance heat resistance. Heat-resistant epoxy resins include epoxy resins containing naphthalene skeletons, anthracene skeletons, and isocyanuric acid skeletons, phenol novolac type epoxy resins for semiconductor encapsulation, novolac type epoxy resins such as cresol novolak type epoxy resins, and triphenolmethane type epoxy resins. High heat resistance such as resins, triphenolalkane epoxy resins such as triphenolpropane epoxy resins, biphenyl epoxy resins, phenol aralkyl epoxy resins, biphenylaralkyl epoxy resins, alicyclic epoxy resins, and heterocyclic epoxy resins. Examples include types.

The curing agent for epoxy resin is one that chemically reacts with the epoxy resin to cure the epoxy resin. As such a hardening agent, any hardening agent that can harden the epoxy resin can be used as appropriate, and its type is not particularly limited. Examples of the curing agent include amine curing agents such as ethylenediamine and polyamidoamine, phthalic anhydride, hexahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, tetrahydrophthalic anhydride, 4-methyltetrahydrophthalic anhydride, and tetrabromo Examples include acid anhydride curing agents such as phthalic anhydride, methylnadic anhydride, dodecenyl succinic anhydride, and pyrolimetic anhydride, and phenolic curing agents such as novolak type phenolic resin and cresol novolak type phenolic resin.

Further, the curing accelerator for epoxy resin increases the curing speed of the epoxy resin. Such curing accelerators can be used as appropriate as long as they accelerate the curing of the epoxy resin, and include tertiary amines such as benzyldimethylamine, imidazoles such as 2-ethyl-4-methylimidazole, and octylic acid. Examples include organic metals such as zinc. Although its type is not particularly limited, it preferably contains at least one of amines, imidazole, and organic zinc.

Examples of the reactive diluent include diallylphthalate, styrene derivatives, (meth)acrylate derivatives, and the like. Examples of diallyl phthalate include ortho diallyl phthalate, meta diallyl phthalate, and para diallyl phthalate, which have different allyl attachment positions on the benzene ring. Examples of styrene derivatives include styrene, 1-methyl-2-vinylbenzene, 1-ethyl-2-vinylbenzene, 1-propyl-2-vinylbenzene, 1-methyl-3-vinylbenzene, 1-ethyl-3 -Vinylbenzene, 1-propyl-3-vinylbenzene, 1-ethyl-4-vinylbenzene, 1-propyl-4-vinylbenzene, 1,2-methyl-4-vinylbenzene, 1,3-methyl-4- Vinylbenzene, 1,4-methyl-4-vinylbenzene, 1,2-ethyl-4-vinylbenzene, 1,3-ethyl-4-vinylbenzene, 1,4-ethyl-4-vinylbenzene, 1,2 -Methyl-5-vinylbenzene, 1,3-methyl-5-vinylbenzene, 1,4-methyl-5-vinylbenzene, 1,2-ethyl-5-vinylbenzene, 1,3-ethyl-5-vinyl Benzene, 1,4-ethyl-5-vinylbenzene, 1,2-methyl-6-vinylbenzene, 1,3-methyl-6-vinylbenzene, 1,4-methyl-6-vinylbenzene, 1,2- Ethyl-6-vinylbenzene, 1,3-ethyl-6-vinylbenzene, 1,4-ethyl-6-vinylbenzene, ortho-t-butylstyrene, m-t-butylstyrene, pt-butylstyrene, etc. can be mentioned. Acrylate derivatives include 2-hydroxyethyl (meth)acrylate, carbitol (meth)acrylate, isobornyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate. , ethylene glycol (meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, polypropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, bis Phenoxyethanol fluorene diacrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, tri((meth)acryloyloxyethyl) phosphate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate Examples include acrylate, dipentaerythritol hexa(meth)acrylate, and the like. These polymerizable unsaturated monomers may be used alone or in combination of two or more. Among these polymerizable unsaturated monomers, it is preferable to use diallyl phthalate, and it is particularly preferable to use meta-diallyl phthalate. Since the diallylphthalate-based polymerizable unsaturated monomer exhibits relatively high heat resistance even when used alone, it is possible to obtain a resin composition with excellent heat resistance compared to other reactive diluents. Further, the polymerizable unsaturated monomer preferably has a viscosity of 50 mPa·s or less at room temperature (25° C.). If a polymerizable unsaturated monomer with a viscosity of more than 50 mPa・s at room temperature is used, the temperature at which the viscosity can be impregnated will be high, and as a result, the time until the resin begins to harden (pot life) will be shortened, making it difficult to work. Sexuality decreases.

The polymerization initiator for the polymerizable unsaturated monomer is preferably one having a half-life temperature of 100°C or higher for 10 hours, such as dicumyl peroxide, 2,5-dimethyl-2,5(dibenzoylperoxy)hexane, etc. , di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, di-t-amyl peroxide, 2,2-di(t-butylperoxy) ) Butane, n-butyl-4,4-di(t-butylperoxy) parerate, ethyl 3,3-di(t-butylperoxy)butyrate, 1,1,3,3-tetramethylbutyl hydroperoxide , t-butyl hydroperoxide, t-amyl hydroperoxide and the like. The upper limit of the 10-hour half-life temperature of the polymerization initiator of the polymerizable unsaturated monomer is not particularly limited, but is usually 170° C. or lower.

The liquid thermosetting resin composition of the present application can be prepared by mixing the above-mentioned components. The liquid thermosetting resin composition thus obtained can be used as a resin composition to be impregnated into a stator coil incorporated into a stator of a high-pressure rotating machine such as an electric motor or a turbine generator, and a glass cloth for a laminate. Although it can be used as a resin composition to be impregnated into an insulating base material such as an organic nonwoven fabric, it is particularly suitable for use as a resin composition for impregnating a stator coil for a high-voltage rotating machine.

The method for curing the liquid thermosetting resin composition according to the present embodiment is not particularly limited, but after impregnating a base material with the liquid thermosetting resin composition, heating the liquid thermosetting resin composition at 200°C or higher. By doing so, the curing reaction of the resin composition can proceed completely, and a cured product with excellent heat resistance can be obtained. In order to allow the reaction of the constituent resin components to proceed stepwise and to sufficiently form a three-dimensional network structure, it is preferable to perform the curing conditions in multiple steps. Specifically, it is preferable to heat at 100° C., 150° C., 180° C., and 200° C. for 1 to 4 hours each, and more preferably for 2 hours at a time.

Embodiment 2.
The stator coil according to Embodiment 2 includes a coil conductor and an insulating layer provided around the coil conductor, and this insulating layer is made of a cured product of the liquid curable resin composition described in Embodiment 1. This includes: As the coil conductor, an electric wire having an insulating coating or a stack of rectangular metal wires covered with an insulating material such as a glass tape can be used.

As shown in FIG. 1, stator coils having a coil conductor 10 and an insulating layer 9 are housed in two stages, upper and lower, within a plurality of slots 12 formed on the inner peripheral side of a stator core 11. A spacer 13 is inserted between these stator coils. A wedge 14 for fixing the stator coil is inserted into the open end of the slot 12.

A stator coil having such a structure is manufactured as follows.
First, an insulating tape is applied multiple times around the outer circumference of a coil conductor 10 made up of a plurality of wires 8 bundled with an insulating coating 7 so that a portion (for example, half the width of the insulating tape) overlaps each other. Wrap it around. Here, the wire constituting the coil conductor 10 is not particularly limited as long as it is conductive, and wires made of copper, aluminum, silver, etc. can be used.

Next, the insulating tape wrapped around the coil conductor 10 is impregnated with a liquid thermosetting resin composition. Here, as the liquid thermosetting resin composition used for impregnation, the one described in Embodiment 1 can be used. The impregnation method is not particularly limited, and methods known in the technical field can be used. Examples of the impregnation method include vacuum impregnation, vacuum pressure impregnation, and normal pressure impregnation. The conditions for impregnation are not particularly limited and may be adjusted as appropriate depending on the liquid thermosetting resin composition used. Note that when an electric wire having an insulating coating is used instead of a rectangular metal wire, the insulating tape may not be provided.

Finally, the insulating layer 9 containing the cured product of the liquid thermosetting resin composition is formed by curing the impregnated liquid thermosetting resin composition. Although the heating temperature for curing is not particularly limited, it is preferable to heat at 100°C for 2 hours, 150°C for 2 hours, 180°C for 2 hours, and 200°C for 2 hours.

Since the stator coil according to this embodiment has excellent heat resistance and strength of the cured resin contained in the insulating layer, it is possible to miniaturize the device, increase output, and improve reliability.

Embodiment 3.
An embodiment in which the stator coil described in Embodiment 2 is applied to a stator of a rotating electrical machine such as a turbine generator will be described. 2 and 3 are diagrams schematically showing main parts of a stator of a rotating electric machine. FIG. 2 is a diagram (cross-sectional view) showing a cross section along the rotation axis of the stator of the rotating electric machine. FIG. 3 is a view (longitudinal cross-sectional view) of a cross section perpendicular to the rotation axis of the stator of the rotating electrical machine, viewed from the direction of arrow A in FIG. 2 and 3, the stator of the rotating electric machine includes a cylindrical stator core 11 that houses the rotor, and a plurality of core tightening members (eight in this example) that tighten the stator core 11 in the axial direction. 15, a plurality of axially flat retaining rings 16 (four locations in this example) that tighten and hold the stator core 11 from above the core tightening member 15 toward the center, and A cylindrical frame 17 surrounding the frame at intervals, a plurality of ring-shaped middle frame members 18 (five in this example), and a plurality of elastic support members 19 (four in this example) made of spring plates. We are prepared. The core tightening members 15 are provided on the outer periphery of the stator core 11 at predetermined intervals in the circumferential direction. The retaining rings 16 are provided on the outer circumference of the stator core 11 at predetermined intervals in the axial direction. The middle frame members 18 protrude in the axial direction from the inner surface of the frame 17 at predetermined intervals in the axial direction. The elastic support member 19 is fixed to each other between adjacent middle frame members 18 and fixed to the retaining ring 16 at the axial center thereof.

The stator shown in FIGS. 2 and 3 constitutes an armature of a turbine generator, for example. A predetermined number of slots formed in the axial direction are provided in the circumferential direction on the inner peripheral portion of the stator core 11, and stator coils are arranged within the slots.

Rotating electric machines such as turbine generators are required to have even higher output and smaller size. In order to achieve higher output and smaller size, it is essential to improve the insulation performance of the coil insulator. By applying the resin according to the present application to a stator coil of a rotating electric machine, it is expected that the output can be further increased and the size can be reduced. Further, these coils are usually made by using a combination of resin and insulating tape, and it is possible to provide coils with excellent insulating properties and ease of manufacture.

The liquid thermosetting resin composition described in Embodiment 1 can be used not only for the stator coil described in Embodiment 2 and the armature of the turbine generator described in Embodiment 3, but also for various motors and power generators. It can be applied to fixing and insulating coils in rotating electric machines such as machines. By insulating the coils in a rotating electrical machine using the liquid thermosetting resin composition described in Embodiment 1, the cured resin with high heat resistance and strength can be used to reduce gaps between the coils and between the rotating machine and the coils. The gaps are filled, improving insulation performance and preventing dielectric breakdown and coil deformation.

Hereinafter, the liquid thermosetting resin composition of the present application will be specifically described with reference to Examples and Comparative Examples.

The bisnaphthalene-type allyl group-containing epoxy compound, bisnaphthalene-type allyl group-containing compound, and naphthalene-type allyl group-containing epoxy compound used in this application were synthesized by the following method.

(A) 5,5'-methylenebis-(6-glycidyloxy-2-naphthalenecarboxylic acid) allyl ether (abbreviated as 5,5'-MBGNA)
Under an argon atmosphere, 5,5'-methylenebis-(6-hydroxy-2-naphthalenecarboxylic acid) (5.87 g, 15 mmol) was dissolved in 50 mL of dry DMF (N,N-dimethylformamide). Next, sodium hydrogen carbonate (5.04 g, 60.0 mmol) was added and cooled to 0°C. After adding 3-bromo-1-propene (4.84 g, 40.0 mmol), stirring was performed at room temperature for 15 hours. The reaction solution was poured into ice water, extracted with ethyl acetate, and then washed with water and saturated brine. After drying the organic layer over anhydrous magnesium sulfate, the solvent is distilled off to obtain a solid 5,5'-methylenebis-(6-hydroxy-2-naphthalenecarboxylic acid allyl ester) represented by the following formula (2), 3.23 g (6.89 mmol, yield 46%) was obtained.
^1H -NMR (600MHz, CHLOROFORM-D) δ8.53 (d, J = 1.4Hz, 2H), 8.21 (d, J = 8.9Hz, 2H), 8.03 (dd, J = 8 .9, 1.7Hz, 2h), 7.76 (d, J = 8.9Hz, 2H), 7.15 (d, J = 8.6Hz, 2H), 7.07 (s, 2H), 6 .13-6.01 (m, 2H), 5.44 (dd, J = 17.2, 1.4Hz, 2H), 5.31 (dd, J = 10.5, 1.2Hz, 2H), 4.87 (d, J=5.5Hz, 4H), 4.80 (s, 2H)

Under an argon atmosphere, 5,5'-methylenebis-(6-hydroxy-2-naphthalenecarboxylic acid allyl ester) (4.05 g, 8.64 mmol) was dissolved in 20 mL of dry DMF. Next, cesium carbonate (8.43 g, 25.9 mmol) and epichlorohydrin (8.0 g, 86.4 mmol) were added, followed by stirring at 50° C. for 20 hours. The reaction solution was poured into ice water, extracted with ethyl acetate, and then washed with water and saturated brine. After drying the organic layer over anhydrous magnesium sulfate, the solvent was distilled off to obtain a crude product. By adding methanol to the crude product and washing the precipitate, 2.81 g (4.84 mmol, yield 56%) of solid 5,5'-MBGNA represented by the following formula (3) was obtained. .
^1H -NMR (600MHz, CHLOROFORM-D) δ8.51 (g, 2H), 8.23 (dd, J = 8.9, 3.1Hz, 2H), 7.94 (dd, J = 8.9 , 1.7Hz, 2H), 7.83 (d, J = 8.9Hz, 2H), 7.28 (dd, J = 8.9, 2.7Hz, 2H), 6.09-6.02 ( m, 2H), 5.42 (dd, J=17.2, 1.5Hz, 2H), 5.29 (dd, J=10.3, 1.4Hz, 2H), 4.98-4.91 (m, 2H), 4.84 (dt, J=5.7, 1.3Hz, 4H), 4.21-4.17 (m, 2H), 4.04 (ddd, J=16.0, 10.5, 5.0Hz, 2H), 3.08-3.03 (m, 2H), 2.74 (dd, J = 8.9, 4.1Hz, 2H), 2.58 (ddd, J =8.4, 5.0, 2.6Hz, 2H)

(B) 4,4'-methylenebis-(3-glycidyloxy-2-naphthalenecarboxylic acid) allyl ether (abbreviated as 4,4'-MBGNA)
Pamoic acid (11.64 g, 30 mmol) was dissolved in 80 mL of dry DMF under an argon atmosphere. Next, sodium bicarbonate (12.60 g, 150 mmol) was added and cooled to 0°C. After addition of 3-bromo-1-propene (10.89 g, 90 mmol), stirring was carried out at room temperature for 12 hours and at 45° C. for 3 hours. The reaction solution was poured into ice water, and the precipitate was filtered and washed with methanol. The filter material was dried to obtain 12.8 g (27.3 mmol, yield 91) of solid 4,4'-methylenebis-(3-hydroxy-2-naphthalenecarboxylic acid allyl ester) represented by the following formula (4). %) was obtained.
^1H -NMR (600MHz, CHLOROFORM-D) δ11.21 (s, 2H), 8.43 (s, 2H), 8.22 (d, J = 8.6Hz, 2H), 7.70 (d, J = 7.9Hz, 2H), 7.37-7.34 (m, 2H), 7.19 (t, J = 7.0Hz, 2H), 6.14-6.07 (m, 2H), 5.49 (dd, J=17.2, 1.4Hz, 2H), 5.37 (dd, J=10.3, 1.0Hz, 2H), 4.95-4.94 (m, 6H)

Under an argon atmosphere, 4,4'-methylenebis-(3-hydroxy-2-naphthalenecarboxylic acid allyl ester) (4.68 g, 10.0 mmol) was dissolved in 10 mL of dry DMF. Next, cesium carbonate (9.77 g, 30 mmol) and epichlorohydrin (9.25 g, 100 mmol) were added, followed by stirring at 60° C. for 18 hours. The reaction solution was poured into ice water, extracted with ethyl acetate, and then washed with water and saturated brine. After drying the organic layer over anhydrous magnesium sulfate, the solvent was distilled off to obtain a crude product. By washing the crude product with hexane, 4.28 g (7.37 mmol, yield 74%) of solid 4,4'-MBGNA represented by the following formula (5) was obtained.
^1H -NMR (600MHz, CHLOROFORM-D) δ8.31 (s, 2H), 8.13 (d, J = 8.6Hz, 2H), 7.75 (d, J = 7.2Hz, 2H), 7.38-7.36 (m, 2H), 7.33-7.30 (m, 2H), 6.16-6.09 (m, 2H), 5.49 (dq, J=17.2 , 1.5Hz, 2H), 5.36-5.34 (m, 2H), 5.09 (s, 2H), 4.92 (dt, J=5.7, 1.2Hz, 4H), 4 .36 (td, J=11.1, 3.2Hz, 2H), 4.06 (qd, J=10.9, 6.1Hz, 2H), 3.48 (td, J=6.3, 3 .0Hz, 2H), 2.88 (t, J=4.5Hz, 2H), 2.75 (td, J=5.2, 2.5Hz, 2H)

(C) 5,5'-methylenebis-(6-glycidyloxy-2-naphthalenecarboxylic acid)-3-methylene-2-butene-1-allyl ester (abbreviated as 5,5'-MBGNMBY)
Under an argon atmosphere, 5,5'-methylenebis-(6-hydroxy-2-naphthalenecarboxylic acid) (3.88 g, 10 mmol) was dissolved in 50 mL of dry DMF. Next, sodium hydrogen carbonate (3.36 g, 40.0 mmol) was added and cooled to 0°C. After addition of 1-bromo-3-methyl-2-butene (3.73 g, 25.0 mmol), stirring was carried out at room temperature for 18 hours. The reaction solution was poured into ice water, extracted with ethyl acetate, and then washed with water and saturated brine. After drying the organic layer over anhydrous magnesium sulfate, the solvent is distilled off to obtain solid 3-methyl 5,5'-methylenebis-(6-hydroxy-2-naphthalenecarboxylate) represented by the following formula (6). -2-buten-1-yl ester), 3.84 g (7.32 mmol, yield 73%) was obtained.
^1H -NMR (600MHz, CHLOROFORM-D) δ8.51 (d, J = 1.7Hz, 2H), 8.19 (d, J = 8.9Hz, 2H), 8.00 (dd, J = 8 .9, 1.7Hz, 2H), 7.76 (d, J = 8.6Hz, 2H), 7.13 (d, J = 8.9Hz, 2H), 6.81 (s, 2H), 5 .51-5.49 (m, 2H), 4.86 (d, J=7.2Hz, 4H), 4.80 (s, 2H), 1.80 (s, 6H), 1.78 (s ,6H)

Under an argon atmosphere, 5,5'-methylenebis-(6-hydroxy-2-naphthalenecarboxylic acid-3-methyl-2-buten-1-yl ester) (1.86 g, 3.54 mmol) was dissolved in 15 mL of dry DMF. Dissolved. Next, cesium carbonate (6.84 g, 21 mmol) and epichlorohydrin (6.44 g, 70 mmol) were added, followed by stirring at 50° C. for 18 hours. The reaction solution was poured into ice water, extracted with ethyl acetate, and then washed with water and saturated brine. After drying the organic layer over anhydrous magnesium sulfate, the solvent was distilled off to obtain 2.01 g (3.15 mmol, yield 89%) of solid 5,5'-MBGNMBY represented by the following formula (7). Obtained.
^1H -NMR (600MHz, CHLOROFORM-D) δ8.46 (d, J = 1.7Hz, 2H), 8.18 (d, J = 8.9Hz, 2H), 8.04 (d, J = 9 .3Hz, 2H), 7.76 (dd, J=9.1, 1.9Hz, 2H), 7.55 (dd, J=9.1, 1.5Hz, 2H), 5.43-5. 40 (m, 2H), 4.87 (s, 2H), 4.77 (d, J = 7.2Hz, 4H), 4.57 (dt, J = 11.5, 3.1Hz, 2H), 4.18-4.14 (m, 2H), 3.31-3.28 (m, 2H), 2.82-2.81 (m, 2H), 2.73-2.71 (m, 2H) ), 1.72 (g, 6H), 1.71 (s, 6H)

(D) 5,5'-methylenebis-(6-glycidyloxy-2-naphthalenecarboxylic acid)-2-methylene-2-propene-1-allyl ester (abbreviated as 5,5'-MBGNMPY)
Under an argon atmosphere, 5,5'-methylenebis-(6-hydroxy-2-naphthalenecarboxylic acid) (3.88 g, 10 mmol) was dissolved in 30 mL of dry DMF. Next, sodium bicarbonate (3.36 g, 40.0 mmol) was added, followed by 1-bromo-2-methyl-2-propene (2.54 mL, 25.0 mmol), and the mixture was further heated at room temperature for 17 hours. The mixture was stirred at 60°C for 5 hours. After cooling to room temperature, the solid content was filtered off through Celite and washed with ethyl acetate. This filtrate was washed with water, saturated aqueous sodium bicarbonate, and saturated brine, and dried by adding anhydrous magnesium sulfate. After removing anhydrous magnesium sulfate by vacuum filtration, the solvent was distilled off under reduced pressure, toluene was added to the residue, and the precipitated solid was separated by filtration, washed with toluene, and dried under reduced pressure to remove the solid 5,5'- 1.20 g of methylenebis-(6-hydroxy-2-naphthalenecarboxylic acid-2-methyl-2-propen-1-yl ester) was obtained. The filtrate was evaporated under reduced pressure, and the residue was purified by silica gel column chromatography to obtain solid 2-methyl-2-propene-1-5,5'-methylenebis-(6-hydroxy-2-naphthalenecarboxylate). ester), 1.13 g was obtained. Total yield of 2.33 g (4 .69 mmol, yield 47%) was obtained.
^1H -NMR (600MHz, CHLOROFORM-D) δ8.54 (d, J = 1.7Hz, 2H), 8.21 (d, J = 8.9Hz, 2H), 8.03 (dd, J = 8 .9, 2.1Hz, 2H), 7.77 (d, J = 8.9Hz, 2H), 7.14 (d, J = 8.9Hz, 2H), 6.91 (s, 2H), 5 .10 (s, 2H), 5.00 (s, 2H), 4.81 (s, 2H), 4.79 (s, 4H), 1.86 (s, 6H)

Under an argon atmosphere, 5,5'-methylenebis-(6-hydroxy-2-naphthalenecarboxylic acid-2-methyl-2-propen-1-yl ester) (2.14 g, 4.31 mmol) was dissolved in 12 g of epichlorohydride. It was suspended in phosphorus and heated to 80°C. A 50% aqueous solution of benzyltrimethylammonium chloride (80 mg, 0.22 mmol) was added dropwise thereto, and the mixture was stirred at 80°C for 2 hours. Further, a 50% aqueous solution of benzyltrimethylammonium chloride (80 mg, 0.22 mmol) was added dropwise thereto, and the mixture was stirred at 80°C for 3 hours. Stir for hours. Next, 800 mg of a 48% aqueous sodium hydroxide solution was added dropwise, and the mixture was stirred at 80° C. for 1 hour. After cooling to room temperature, 60% methanol aqueous solution was added and stirred, and the precipitate was filtered off, washed with methanol, and dried under reduced pressure to obtain a solid 5,5'-MBGNMPY represented by the following formula (9), 2.5 g (4.11 mmol, yield 95%) was obtained.
^1H -NMR (600MHz, CHLOROFORM-D) δ8.52 (d, J = 1.7Hz, 2H), 8.21 (dd, J = 8.9, 2.1Hz, 2H), 8.06 (d , J = 8.9Hz2H), 7.80 (dd, J = 9.1, 1.9Hz, 2H), 7.56 (dd, J = 9.1, 1.2Hz, 2H), 5.02 ( s, 2H), 4.94 (s, 2H), 4.88 (s, 2H), 4.71 (s, 4H), 4.59-4.56 (m, 2H), 4.18-4 .14 (m, 2H), 3.31-3.29 (m, 2H), 2.82-2.81 (m, 2H), 2.73-2.72 (m, 2H), 1.76 (s, 6H)

(E) 1,1'-bis(2,7-hydroxy-1-naphthyl)methanetetraallyl carbonate (abbreviated as TAC-BHNM)
Under an argon atmosphere, 1,1'-bis(2,7-hydroxy-1-naphthyl)methane (BHNM) (10.0 g, 30.09 mmol) was dispersed in 90 mL of toluene and 30 mL of DMF. Next, triethylamine (25.2 mL, 180.5 mmol) was added and cooled to 0° C., and allyl chloroformate (15.9 mL, 150.5 mmol) was added dropwise over 10 minutes. After the reaction solution was heated to room temperature and stirred for 4.5 hours, DMF (60ml) was added and further stirred for 18.5 hours. Water was added to the reaction solution, and the precipitate was separated by filtration and washed with water and toluene. The toluene layer of the filtrate was separated, washed with saturated brine, and dried by adding anhydrous magnesium sulfate. After removing magnesium sulfate by vacuum filtration, the solvent was distilled off under reduced pressure, methanol was added to the residue, the precipitate was separated by filtration, washed with methanol, and dried under reduced pressure to obtain the following formula (10). 15.8 g (23.63 mmol, yield 79%) of the solid TAC-BHNM shown above was obtained.
¹ H-NMR (600 MHz, CHLOROFORM-D) δ7.91 (d, J = 2.1 Hz, 2H), 7.85 (d, J = 8.9 Hz, 2H), 7.76 (d, J = 8 .9Hz, 2H), 7.30 (dd, J=8.9, 2.1Hz, 2H), 7.21 (d, J=8.6Hz, 2H), 6.02-5.96 (m, 2H), 5.84-5.77 (m, 2H), 5.42 (dq, J = 17.2, 1.4Hz, 2H), 5.33 (dq, J = 10.4, 1.1Hz , 2H), 5.28dq, J=17.2, 1.5Hz, 2H), 5.24-5.22(m, 2H), 4.73(dt, J=5.8, 1.4Hz, 4H), 4.72 (s, 2H), 4.43 (dt, J=5.8, 1.4Hz, 4H)

(F) 1,1'-bis(2,7-hydroxy-1-naphthyl)methanetetramethacrylate (abbreviated as TMA-BHNM)
Under an argon atmosphere, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (8.45 g, 44.1 mmol) and N,N-dimethyl-4-aminopyridine (1.27 g, 10.4 mmol) were combined. Methacrylic acid (3.81 g, 44.2 mmol) was dissolved in 30 mL of acetonitrile. A solution of 1,1-bis(2,7-hydroxy-1-1naphthyl)methane (BHNM) (3.31 g, 10.0 mmol) dissolved in 70 mL of acetonitrile was added thereto at room temperature, and the mixture was left for 2 days. Stirred. After distilling off acetonitrile, the residue was dissolved in ethyl acetate, and insoluble materials were filtered off. Thereafter, the filtrate was washed with water, concentrated, and purified by column chromatography to obtain 1.30 g (2.2 mmol, yield 22%) of solid TMA-BHNM represented by the following formula (11).
¹ H-NMR (600 MHz, CHLOROFORM-D) δ7.87 (d, J = 2.1 Hz, 2H), 7.84 (d, J = 8.9 Hz, 2H), 7.74 (d, J = 8 .6Hz, 2H), 7.24 (dd, J=8.8, 2.2Hz, 2H), 7.12 (d, J=8.9Hz, 2H), 6.34 (s, 2H), 5 .88 (s, 2H), 5.76 (t, J = 1.5Hz, 2H), 5.45 (t, J = 1.4Hz, 2H), 4.61 (s, 2H), 2.06 (s, 6H), 1.76 (s, 6H)

(G) 6-(2-oxiranylmethoxy)-2-naphthoic acid alkenyl ester (abbreviated as 6-GNA)
Under an argon atmosphere, 3.76 g (20.0 mmol) of 6-hydroxy-2-naphthoic acid was dissolved in 20 mL of dry DMF. Next, 3.36 g (40.0 mmol) of sodium hydrogen carbonate was added, and the mixture was cooled to 0°C. After adding allyl bromide (2.90 g, 24.0 mmol), stirring was performed at room temperature for 18 hours. The reaction solution was poured into ice water, extracted with ethyl acetate, and then washed with water and saturated brine. After drying the organic layer over anhydrous magnesium sulfate, the solvent was distilled off to obtain 3.293 g (14.4 mmol, yield) of solid 6-hydroxy-2-naphthoic acid allyl ester represented by the following formula (12). 72%).
^1H -NMR (600MHz, CHLOROFORM-D) δ8.56 (d, J = 1.0Hz, 1H), 8.03 (dd, J = 8.6, 1.7Hz, 1H), 7.86 (d , J=8.6Hz, 1H), 7.70 (d, J=8.6Hz, 1H), 7.19 (d, J=2.4Hz, 1H), 7.17 (dd, J=8. 8, 2.6Hz, 1H), 6.12-6.06 (m, 1H), 5.67 (s, 1H), 5.45 (dq, J=17.2, 1.5Hz, 1H), 5.32 (dq, J=10.5, 1.3Hz, 1H), 4.89 (dt, J=5.5, 1.4Hz, 2H)

Under an argon atmosphere, 6-hydroxy-2-naphthoic acid allyl ester (3.29 g, 14.4 mmol) was dissolved in 10 mL of dry DMF. Next, cesium carbonate (7.02 g, 21.6 mmol) and epichlorohydrin (6.66 g, 72.0 mmol) were added, followed by stirring at 40° C. for 18 hours. The reaction solution was poured into ice water, extracted with ethyl acetate, and then washed with water and saturated brine. After drying the organic layer over anhydrous magnesium sulfate, the solvent was distilled off to obtain 3.210 g of solid 6-(2-oxiranylmethoxy)-2-naphthoic acid alkenyl ester represented by the following formula (13). (11.3 mmol, yield 78%) was obtained.
^1H -NMR (600MHz, CHLOROFORM-D) δ8.55 (s, 1H), 8.05 (dd, J = 8.6, 1.0Hz, 1H), 7.86 (d, J = 8.9Hz , 1H), 7.75 (d, J=8.6Hz, 1H), 7.24 (dd, J=8.9, 2.4Hz, 1H), 7.16 (d, J=2.4Hz, 1H), 6.09 (qd, J = 11.0, 5.8Hz, 1H), 5.45 (d, J = 17.2Hz, 1H), 5.32 (d, 1H), 4.88 ( d, J=5.5Hz, 2H), 4.39 (dd, J=10.8, 2.9Hz, 1H), 4.09 (dd, J=11.0, 5.8Hz, 1H), 3 .45-3.43 (m, 1H), 2.96 (t, J = 4.5Hz, 1H), 2.82 (dd, J = 4.6, 2.6Hz, 1H)

In order to unify the conditions, the resin composition used in the present application was adjusted so that the weight of the reactive diluent was 70% relative to the weight of the compound having a bisnaphthalene skeleton or naphthalene skeleton as the main component, which was 30%. Further, the epoxy resin curing agent was blended at an epoxy equivalent ratio of 0.9 in the resin composition. The curing accelerator was blended in an amount of 2% based on the mass of the base resin. The polymerization initiator was blended in an amount of 3% based on the mass of the reactive diluent.

[Example 1]
25.4 parts by mass of 5,5'-methylenebis-(6-glycidyloxy-2-naphthalenecarboxylic acid) allyl ether as a bisnaphthalene-type allyl group-containing epoxy compound, and alicyclic acid anhydride as a curing agent for epoxy resin. (trade name "HN-5500", manufactured by Hitachi Chemical Co., Ltd.) at an epoxy equivalent ratio of 0.9 and 13.2 parts by mass, and 59.0 parts of isoDAP (manufactured by Osaka Soda Co., Ltd.) as a reactive diluent. 1 part by mass, 0.5 parts by mass of 2E4MZ (2-Ethyl-4-methylimidazole, manufactured by Shikoku Kasei Co., Ltd.) as a curing accelerator, and 1 part of dicumyl peroxide (DCP, manufactured by NOF Corporation) as a polymerization initiator. .8 parts by mass was used. For mixing, first, the bisnaphthalene type compound described in formula (1) was dissolved under 130°C conditions. Then, after adding the acid anhydride and isoDAP, the mixture was cooled to 60°C or lower. 2E4MZ and DCP were added and mixed well. After degassing under vacuum, it was poured into a mold and heated to harden. Heating was carried out at 100°C for 2 hours, at 150°C for 2 hours, at 180°C for 2 hours, and at 200°C for 2 hours.

[Example 2]
The same method as in Example 1 was used except that 25.4 parts by mass of 4,4'-methylenebis-(3-glycidyloxy-2-naphthalenecarboxylic acid) allyl ether was used as the bisnaphthalene-type allyl group-containing epoxy compound. The treatment was carried out to create a cured product.

[Example 3]
As a bisnaphthalene-type allyl group-containing epoxy compound, 11.8 parts by mass of 5,5'-methylenebis-(6-glycidyloxy-2-naphthalenecarboxylic acid) allyl ether, HP4700 (1,1'-bis(2,7 -diglycidyloxy-1-naphthyl)alkane (manufactured by DIC Corporation), 11.8 parts by mass, 19.0 parts by mass of alicyclic acid anhydride HN-5500 as an epoxy resin curing agent, as a reactive diluent. 55.2 parts by mass of isoDAP, 0.5 parts by mass of 2E4MZ as a curing accelerator, and 1.7 parts by mass of dicumyl peroxide as a polymerization initiator were used. For mixing, first, 5,5'-methylenebis-(6-glycidyloxy-2-naphthalenecarboxylic acid) allyl ether and HP4700 were dissolved under 130°C and mixed well. Then, after adding the acid anhydride and isoDAP, the mixture was cooled to 60°C or lower. 2E4MZ and DCP were added and mixed well. After degassing under vacuum, it was poured into a mold and heated to harden. Heating was carried out at 100°C for 2 hours, at 150°C for 2 hours, at 180°C for 2 hours, and at 200°C for 2 hours.

[Comparative example 1]
22.2 parts by mass of HP4700 as the main epoxy resin, 24.1 parts by mass of HN-5500 as an epoxy resin curing agent, 51.7 parts by mass of IsoDAP as a reactive diluent, and 0 parts of 2E4MZ as a reaction accelerator. A cured product was prepared in the same manner as described in Example 1, except that 1.6 parts by mass of dicumyl peroxide was used as a polymerization initiator.

[Comparative example 2]
23.2 parts by mass of bisphenol A epoxy resin (JER828, manufactured by Mitsubishi Chemical Corporation) was used as the main epoxy resin, 20.5 parts by mass of HN-5500 was used as the epoxy resin curing agent, and IsoDAP was used as the reactive diluent. 54.2 parts by mass, 0.5 parts by mass of 2E4MZ as a curing accelerator, and 1.6 parts by mass of dicumyl peroxide as a polymerization initiator. A cured product was created.

[Comparative example 3]
As a bisnaphthalene type compound, allyl-modified 5,5'-methylenebis-(6-glycidyloxy-2-naphthalenecarboxylic acid)-3-methylene-2-butene-1- of the compound described in formula (1) is used. 25.7 parts by mass of allyl ester, 12.1 parts by mass of HN-5500 as an epoxy resin curing agent, 59.9 parts by mass of isoDAP as a reactive diluent, 0.5 parts by mass of 2E4MZ as a curing accelerator, A cured product was prepared in the same manner as described in Example 1 except that 1.8 parts by mass of dicumyl peroxide was used as a polymerization initiator.

[Comparative example 4]
As a bisnaphthalene type compound, allyl-modified 5,5'-methylenebis-(6-glycidyloxy-2-naphthalenecarboxylic acid)-2-methylene-2-propene-1- of the compound described in formula (1) is used. 25.5 parts by mass of allyl ester, 12.7 parts by mass of HN-5500 as an epoxy resin curing agent, 59.5 parts by mass of isoDAP as a reactive diluent, 0.5 parts by mass of 2E4MZ as a curing accelerator, A cured product was prepared in the same manner as described in Example 1 except that 1.8 parts by mass of dicumyl peroxide was used as a polymerization initiator.

[Comparative example 5]
29.1 parts by mass of 1,1'-bis(2,7-hydroxy-1-naphthyl)methanetetraallyl carbonate as a bisnaphthalene type compound, 68.0 parts by mass of isoDAP as a reactive diluent, and curing accelerated. No agent was used, and 2.9 parts by mass of 1,1'-di(t-amylperoxy)cyclohexane (Luperoc 531, manufactured by Arkema Yoshitomi Co., Ltd.) was used as a polymerization initiator. TAC-BHMN has a carbonate group (-O-(C=O)-O-), and since a cured product could not be obtained with dicumyl peroxide, 1,1'-di(t-amyl Peroxy)cyclohexane was used. First, the bisnaphthalene type compound was dissolved at 130°C, and isoDAP was added thereto, followed by cooling to 30°C or lower. Luperoc 531 was added and mixed well. After degassing under vacuum, it was poured into a mold and heated to harden.

[Comparative example 6]
29.1 parts by mass of 1,1'-bis(2,7-hydroxy-1-naphthyl)methanetetramethacrylate as a bisnaphthalene type compound, 68.0 parts by mass of isoDAP as a reactive diluent, and a curing accelerator. A cured product was produced by processing in the same manner as described in Comparative Example 3, except that 2.9 parts by mass of dicumyl peroxide was used as a polymerization initiator.

[Comparative example 7]
23.6 parts by mass of 6-(2-oxiranylmethoxy)-2-naphthoic acid alkenyl ester as naphthalene type allyl-containing epoxy resin, 19.3 parts by mass of HN-5500 as epoxy resin curing agent, reactive dilution The same procedure as described in Example 1 was used, except that 55.0 parts by mass of isoDAP was used as the agent, 0.5 parts by mass of 2E4MZ was used as the curing accelerator, and 1.6 parts by mass of dicumyl peroxide was used as the polymerization initiator. A cured product was prepared by processing according to the method.

[Comparative example 8]
97 parts by mass of isoDAP as a reactive diluent and 3 parts by mass of dicumyl peroxide as a polymerization initiator were thoroughly mixed at 25°C, defoamed under vacuum, and then cast into a mold. Heat and harden. Heating was carried out at 100°C for 2 hours, at 150°C for 2 hours, at 180°C for 2 hours, and at 200°C for 2 hours.

<Evaluation test>
The viscosity of each of Examples 1 to 3 and Comparative Examples 1 to 8 in a liquid state before heating was evaluated by the following method. The viscosity of the resin material was measured using an E-type viscometer (RE115U, manufactured by Toki Sangyo Co., Ltd.) at a rotation speed of 0.5 to 20 rpm and maintained at 25° C. using a constant temperature bath.

The heat resistance of each of the cured products of Examples 1 to 3 and Comparative Examples 1 to 8 was evaluated by measuring the glass transition temperature. The measurement method is as follows.
The heat resistance of the cured product was evaluated by the glass transition temperature obtained from dynamic viscoelasticity measurement. Dynamic viscoelastic behavior was measured using a viscoelastic spectrometer (RSA-III, manufactured by TA Instruments Co., Ltd.) using a three-point bending method at a frequency of 1 Hz and a heating rate of 2° C./min. The alpha relaxation of the temperature dispersion curve of loss tangent in dynamic viscoelasticity measurements was regarded as the glass transition temperature (Tg).

Table 1 shows the evaluation results of the resin composition, viscosity at 25° C., and glass transition temperature of Examples 1 to 3. Table 2 shows the evaluation results of the resin composition, viscosity at 25° C., and glass transition temperature of Comparative Examples 1 to 8.

The viscosity was determined to be effective by lowering the viscosity from the 0.17 Pa·s of Comparative Example 1 containing a highly heat-resistant epoxy resin. By lowering the viscosity below 0.17 Pa·s (25° C.), the resin can easily penetrate into the fine spaces between the windings even in the temperature range near room temperature. Moreover, the workability of varnish can be improved.

Regarding heat resistance, a glass transition temperature of 155° C. or higher was judged to be effective. By setting the temperature to 155° C. or higher, it can be expected that the long-term heat-resistant life of the insulating material will satisfy the F class equivalent (155° C. or higher).

The viscosities of Examples 1 to 3 and Comparative Examples 1 to 8 are compared. Comparative Example 8 has a viscosity of only the reactive diluent, and by adding other resin components, the viscosity becomes higher than 0.03 Pa·s. Comparative Example 1 contains high heat-resistant epoxy resin HP4700, and the presence of four epoxy groups increases the viscosity due to the influence of hydrogen bonds between monomers. Examples 1 to 3 and Comparative Examples 2 to 7 all exhibited lower viscosities than Comparative Example 1. Lower viscosity was observed by changing from epoxy group to allyl group.

Comparative Example 1 exhibits a high glass transition temperature because it contains a highly heat-resistant epoxy, but has a high viscosity. In Comparative Example 2, since a single epoxy resin is used, the viscosity is low, but the heat resistance temperature is also low. As described above, with conventional resin materials, it is difficult to achieve both low viscosity and high heat resistance.

Examples 1 to 3 have lower viscosities than Comparative Example 1, and exhibit heat resistance with glass transition temperatures exceeding 155°C. By using a bisnaphthalene-type allyl-containing epoxy compound, it is possible to suppress a decrease in heat resistance and lower the viscosity.

Comparative Example 7 uses a naphthalene-type allyl-containing epoxy compound, but it was confirmed that the heat resistance was insufficient because it had one naphthalene skeleton.

Although this application describes various exemplary embodiments and examples, various features, aspects, and functions described in one or more embodiments may be applicable to a particular embodiment. The present invention is not limited to, and can be applied to the embodiments alone or in various combinations. Accordingly, countless variations not illustrated are envisioned within the scope of the technology disclosed herein. For example, this includes cases where at least one component is modified, added, or omitted, and cases where at least one component is extracted and combined with components of other embodiments.

Claims (11)

an epoxy compound, a curing agent for curing the epoxy compound, a diluent for diluting the epoxy compound, a curing accelerator for accelerating curing of the epoxy compound, and a polymerization initiator for initiating a polymerization reaction of the epoxy compound. A liquid thermosetting resin composition comprising:
A liquid thermosetting resin composition, wherein the epoxy compound includes a compound represented by the following formula (1) .

(R ₁ and R ₂ in the formula are R ₁ :COOCH ₂ CH=CH ₂ , R ₂ :H, or R ₁ :H, R ₂ :COOCH ₂ CH=CH ₂ .) The liquid thermosetting resin composition according to claim 1 , wherein the epoxy compound is 5,5'-methylenebis-(6-glycidyloxy-2-naphthalenecarboxylic acid) allyl ether. The liquid thermosetting resin composition according to claim 1 , wherein the epoxy compound is 4,4'-methylenebis-(3-glycidyloxy-2-naphthalenecarboxylic acid) allyl ether. The liquid thermosetting resin composition according to any one of claims 1 to 3 , wherein the epoxy compound contains one or more epoxy compounds having heat resistance other than a bisnaphthalene skeleton. Any one of claims 1 to 3, wherein the epoxy compound contains 1,1'-bis(2,7-diglycidyloxy-1-naphthyl)alkane as a heat-resistant epoxy compound. The liquid thermosetting resin composition according to item 1 . The liquid thermosetting resin composition according to any one of claims 1 to 5 , wherein the curing agent is an acid anhydride. The liquid thermosetting resin composition according to any one of claims 1 to 6 , wherein the diluent is diallyl phthalate. The liquid thermosetting resin composition according to any one of claims 1 to 7 , wherein the curing accelerator contains at least one of amine, imidazole, and organic zinc. A method comprising the steps of impregnating a base material with the liquid thermosetting resin composition according to any one of claims 1 to 8 , and heating the resin composition in multiple steps. A method for curing a liquid thermosetting resin composition. A stator coil comprising a coil conductor and a resin layer provided around the coil conductor, the resin layer comprising the liquid thermosetting resin according to any one of claims 1 to 8 . A stator coil comprising a cured product of the composition. A rotating electric machine characterized in that the stator coil according to claim 10 is housed in a slot of a stator core.

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