Molded stator and motor

Abstract

Provided is a molded stator which comprises a stator comprising a stator core and a coil wound on the stator core and a molding material covering the stator, wherein the molding material is a cured object formed from a heat-curable resin composition comprising (A) a saturated polyester resin, (B) one or more unsaturated polyester resins, (C) an ethylenically unsaturated monomer, (D) a thermal polymerization initiator, (E) glass fibers, and (F) an inorganic filler. The unsaturated polyester resins (B) at least include (B-1) an unsaturated polyester resin, the unsaturated polyester resin (B-1) being a product of polycondensation of a mixture comprising a diol and an unsaturated polybasic acid, and the unsaturated polyester resin (B-1) including a structure derived from propylene glycol and a structure derived from neopentyl glycol.

Description

Molded stators and motors

[0001] The present disclosure relates to a molded stator, a motor including the molded stator, and a thermosetting resin composition.

[0002] There is a growing demand for smaller, thinner, lighter, and more powerful motors and transformers for home appliances. Furthermore, due to the characteristics of the environment in which these appliances are used, they must be low-noise and low-vibration. To meet this demand, a structure has been proposed in which an electromagnetic coil wound around a stator core is covered with a molded resin (see Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2023-091064

[0004] When molding a stator so that it is covered with mold resin, the increasingly complex shape of the stator results in thin and thick sections in the hardened mold resin. Furthermore, the need to reduce the amount of mold resin to the utmost is becoming necessary as the stator becomes thinner and lighter. As a result, the mold resin lacks strength as it hardens, causing cracks in the molded product.

[0005] The present disclosure provides a molded stator covered with a molding material that is crack-free and has a good appearance.

[0006] The present disclosure includes the following aspects: [1] A molded stator including: a stator having a stator core and a coil wound around the stator core; and a molding material covering the stator, wherein the molding material is a cured product of a thermosetting resin composition containing (A) a saturated polyester resin, (B) an unsaturated polyester resin, (C) an ethylenically unsaturated monomer, (D) a thermal polymerization initiator, (E) glass fiber, and (F) an inorganic filler, wherein the (B) unsaturated polyester resin contains at least an (B-1) unsaturated polyester resin, and the (B-1) unsaturated polyester resin is a polycondensate of a mixture containing a diol and an unsaturated polybasic acid, and the (B-1) unsaturated polyester resin contains a structure derived from propylene glycol and a structure derived from neopentyl glycol. [2] The molded stator according to [1], wherein the ratio (molar ratio) of the structure derived from propylene glycol to the structure derived from neopentyl glycol in the unsaturated polyester resin (B-1) is 10:90 to 90:10. [3] The molded stator according to [1] or [2], wherein the unsaturated polyester resin (B-1) further contains a structure derived from hydrogenated bisphenol A. [4] The molded stator according to any one of [1] to [3], wherein the unsaturated polyester resin (B) further contains an unsaturated polyester resin (B-2), the unsaturated polyester resin (B-2) being a polycondensate of a mixture containing a diol and an unsaturated polybasic acid, and the unsaturated polyester resin (B-2) contains a structure derived from propylene glycol but does not contain a structure derived from neopentyl glycol. [5] The molded stator according to any one of [1] to [4], wherein the unsaturated polyester resin (B-1) contains a structure derived from a saturated polybasic acid. [6] The molded stator according to [4], wherein the unsaturated polyester resin (B-2) contains a structure derived from a saturated polybasic acid. [7] The molded stator according to any one of [1] to [6], wherein the weight average molecular weight of the unsaturated polyester resin (B-1) is 10,000 to 50,000.[8] The molded stator according to any one of [1] to [7], wherein the (A) saturated polyester resin is a polycondensate of a mixture containing a diol and a saturated polybasic acid, and the saturated polybasic acid contains an aromatic saturated polybasic acid or an acid anhydride thereof, and an aliphatic saturated polybasic acid. [9] The molded stator according to [8], wherein the (A) saturated polyester resin contains a block (X) which is a polycondensate of a diol and a saturated aromatic polybasic acid or an acid anhydride thereof, and a block (Y) which is a polycondensate of a diol and a saturated aliphatic polybasic acid, and wherein the weight average molecular weight of the block (X) is 3,000 to 5,000.

[10] The molded stator according to [9], wherein the aromatic saturated polybasic acid constituting the block (X) is one or more selected from isophthalic acid and terephthalic acid.

[11] The molded stator according to [9] or

[10] , wherein the aliphatic saturated polybasic acid constituting the block (Y) is one or more selected from succinic acid, adipic acid, and sebacic acid.

[12] The molded stator according to any one of [1] to

[11] , wherein the weight average molecular weight of the saturated polyester resin (A) is 9,500 to 13,500.

[13] The molded stator according to any one of [1] to

[12] , wherein the thermosetting resin composition contains, relative to 100 parts by mass of the total amount of the (B) unsaturated polyester resin and the (C) ethylenically unsaturated monomer, 5 to 30 parts by mass of the (A) saturated polyester resin, 20 to 80 parts by mass of the (B) unsaturated polyester resin, 80 to 20 parts by mass of the (C) ethylenically unsaturated monomer, 0.5 to 20 parts by mass of the (D) thermal polymerization initiator, 5 to 150 parts by mass of the (E) glass fiber, and 50 to 1000 parts by mass of the (F) inorganic filler.

[14] A motor comprising: the molded stator according to any one of [1] to

[13] , a rotor having a rotating shaft extending in an axial direction, and a rotating body including a magnet component extending in the axial direction and fixed to the rotating shaft, the rotor being positioned inside the stator, and a bearing rotatably supporting the rotor.

[15] A thermosetting resin composition comprising (A) a saturated polyester resin, (B) an unsaturated polyester resin, (C) an ethylenically unsaturated monomer, (D) a thermal polymerization initiator, (E) glass fiber, and (F) an inorganic filler, wherein the (B) unsaturated polyester resin contains at least an (B-1) unsaturated polyester resin, the (B-1) unsaturated polyester resin being a polycondensate of a mixture containing a diol and an unsaturated polybasic acid, and the (B-1) unsaturated polyester resin contains a structure derived from propylene glycol and a structure derived from neopentyl glycol.

[16] The thermosetting resin composition according to

[15] , wherein the (B-1) unsaturated polyester resin further contains a structure derived from hydrogenated bisphenol A.

[17] The thermosetting resin composition according to

[15] or

[16] , wherein the saturated polyester resin (A) is a polycondensate of a mixture containing a diol and a saturated polybasic acid, the saturated polybasic acid containing an aromatic saturated polybasic acid or its acid anhydride and an aliphatic saturated polybasic acid, the content ratio (molar ratio) of the structure derived from the aromatic saturated polybasic acid or its acid anhydride to the structure derived from the aliphatic saturated polybasic acid in the saturated polyester resin (A) is 20:80 to 80:20, the saturated polyester resin (A) contains a block (X) which is a polycondensate of a diol and an aromatic saturated polybasic acid or its acid anhydride, and a block (Y) which is a polycondensate of a diol and an aliphatic saturated polybasic acid, and the weight average molecular weight of the block (X) is 3,000 to 5,000.

[18] The thermosetting resin composition according to any one of

[15] to

[17] , comprising: 5 to 30 parts by mass of the (A) saturated polyester resin; 20 to 80 parts by mass of the (B) unsaturated polyester resin; 80 to 20 parts by mass of the (C) ethylenically unsaturated monomer, relative to 100 parts by mass of the total amount of the (B) unsaturated polyester resin and the (C) ethylenically unsaturated monomer; 0.5 to 20 parts by mass of the (D) thermal polymerization initiator; 5 to 150 parts by mass of the (E) glass fiber; and 50 to 1000 parts by mass of the (F) inorganic filler.

[19] A molding material that is a cured product of the thermosetting resin composition according to any one of

[15] to

[18] .

[0007] According to the present disclosure, it is possible to provide a molded stator covered with a molding material that is free of cracks and has a good appearance.

[0008] FIG. 1 is a cross-sectional schematic view of an exemplary motor.

[0009] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the embodiments described below.

[0010] In this specification, when "to" is used to describe a numerical range, the numerical values ​​at both ends are the upper and lower limits, respectively, and are included in the numerical range. When multiple upper or lower limits are listed, numerical ranges can be created using all combinations of the upper and lower limits. Similarly, when multiple numerical ranges are listed, separate numerical ranges can be created by individually selecting and combining the upper and lower limits from those numerical ranges.

[0011] In this specification, "(meth)acrylic acid" means methacrylic acid or acrylic acid, "(meth)acrylate" means acrylate or methacrylate, and "(meth)acryloyloxy" means acryloyloxy or methacryloyloxy.

[0012] In this specification, the term "thermosetting resin" refers to a resin that hardens by forming a crosslinked structure when heated, and indicates the resin in the pre-hardened state.

[0013] In this specification, the term "ethylenically unsaturated bond" means a double bond formed between carbon atoms excluding carbon atoms forming an aromatic ring, and the term "ethylenically unsaturated monomer" means a monomer having an ethylenically unsaturated bond.

[0014] In this specification, the "weight average molecular weight" and "number average molecular weight" refer to values ​​measured using gel permeation chromatography (GPC) at room temperature (23°C) under the following conditions and determined using a standard polystyrene calibration curve. Apparatus: Shodex™ GPC-101 (Resonac Inc.) Column: Shodex™ LF-804 (Resonac Inc.) Column temperature: 40°C Sample: 0.2% by mass solution of sample in tetrahydrofuran Flow rate: 1 mL / min Eluent: Tetrahydrofuran Detector: Shodex™ RI-71S (Resonac Inc.)

[0015] In this specification, the term "acid value" refers to the acid value measured in accordance with JIS K6901:2021 5.3. That is, the acid value refers to the number of milligrams of potassium hydroxide required to neutralize the acidic components contained in 1 g of nonvolatile matter excluding the solvent.

[0016] <Motor> A motor is a device that generates a rotational force by passing current through an internal coil to generate an electromagnetic force and by the repulsive or attractive force between the coil and a main shaft or a permanent magnet or electromagnet provided around the main shaft. Generally, a motor includes a stator having a stator core and a coil wound around the stator core, and a rotating body including a magnetic component. A motor in which the stator is covered with a molding material is also called a molded motor. In this specification, a stator covered with a molding material is referred to as a molded stator.

[0017] In one embodiment, the motor comprises: a molded stator; a rotating shaft extending in the axial direction; a rotating body including a magnetic component, extending in the axial direction, and fixed to the rotating shaft, the rotor being positioned inside the stator; and a bearing that rotatably supports the rotor.

[0018] In the motor, the molding material constituting the molded stator is a cured product of a thermosetting resin composition, which will be described later. The components of the motor other than the molding material may be any known components.

[0019] A cross-sectional view of an exemplary motor is shown in FIG. 1. Detailed components such as brackets and insulators attached to the coils are omitted from FIG. 1. In FIG. 1, motor 10 includes stator 11, rotor 15, and bearings 19 that rotatably support rotor 15. Stator 11 includes stator core 12 made of multiple metal plates and coils 13 with windings wound around stator core 12. Stator 11 is covered with molding material 14. Rotor 15 is located inside stator 11. Rotor 15 includes a rotating shaft 17 extending axially and a rotating body 18 fixed to rotating shaft 17, and rotating body 18 includes magnets 16.

[0020] <Molded Stator> The molded stator is a stator covered with a molding material. In one embodiment, the molded stator includes a stator having a stator core and a coil wound around the stator core, and a molding material that covers the stator. Note that the entire stator does not need to be covered with the molding material.

[0021] The molding material constituting the molded stator is a cured product of a thermosetting resin composition described below. The components of the molded stator other than the molding material may be any known component. There are no particular limitations on the motor to which the molded stator is applied, and any known component may be used.

[0022] <Molding Material> The molding material is a cured product of a thermosetting resin composition, which will be described later. By using the molding material, a motor with low noise and vibration can be obtained.

[0023] <Thermosetting Resin Composition> A thermosetting resin composition according to one embodiment contains (A) a saturated polyester resin, (B) an unsaturated polyester resin, (C) an ethylenically unsaturated monomer, (D) a thermal polymerization initiator, (E) glass fiber, and (F) an inorganic filler. The (B) unsaturated polyester resin contains at least an unsaturated polyester resin (B-1). The (B-1) unsaturated polyester resin is a polycondensate of a mixture containing a diol and an unsaturated polybasic acid. The (B-1) unsaturated polyester resin contains a structure derived from propylene glycol and a structure derived from neopentyl glycol. A cured product of the thermosetting resin composition is suitable for use as a molding material for covering a stator. By using a cured product of the thermosetting resin composition containing the (B-1) unsaturated polyester resin having a specific structure as a molding material, a molded stator with a good appearance and no cracks can be obtained. Furthermore, a molded stator with excellent durability against heat cycles can be obtained.

[0024] [(A) Saturated Polyester Resin] The (A) saturated polyester resin is a polycondensate of a polyhydric alcohol and a saturated polybasic acid. The (A) saturated polyester resin is preferably a polycondensate of a mixture containing a diol and a saturated polybasic acid, more preferably a polycondensate of a mixture containing a diol, an aromatic saturated polybasic acid or its acid anhydride, and an aliphatic saturated polybasic acid. Among the polyhydric alcohol-derived structures of the (A) saturated polyester resin, the diol-derived structures are preferably 95 mol % or more, more preferably 98 mol % or more, and even more preferably 100 mol %. Among the polyhydric alcohol-derived structures of the (A) saturated polyester resin, the upper limit of the diol-derived structures may be 100 mol % or 99 mol %. Among the saturated polybasic acid-derived structures of the (A) saturated polyester resin, the structures derived from either an aromatic saturated polybasic acid, its acid anhydride, or an aliphatic saturated polybasic acid are preferably 95 mol % or more, more preferably 98 mol % or more, and even more preferably 100 mol %. In the structure derived from the saturated polybasic acid of the (A) saturated polyester resin, the upper limit of the structure derived from any one of an aromatic saturated polybasic acid, an acid anhydride thereof, and an aliphatic saturated polybasic acid may be 100 mol % or 99 mol %.

[0025] The saturated polyester resin (A) may be used alone or in combination of two or more thereof. By using the saturated polyester resin (A), the occurrence of cracks during molding is suppressed.

[0026] In the present disclosure, styrene monomers and the like contained in commercially available saturated polyester resins are classified as (C) ethylenically unsaturated monomers.

[0027] The polyhydric alcohol is not particularly limited as long as it is a compound having two or more hydroxyl groups. The polyhydric alcohol is preferably one or more selected from the group consisting of diols and triols, and more preferably a diol. Examples of the polyhydric alcohol include alkylene glycols such as ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, neopentyl glycol, 2-methyl-1,3-propanediol, 1,4-cyclohexanedimethanol, and hydrogenated bisphenol A; polyoxyalkylene polyols such as diethylene glycol, dipropylene glycol, triethylene glycol, tetraethylene glycol, and polyethylene glycol; bisphenol A; alkylene oxide-modified bisphenol A such as an ethylene oxide adduct of bisphenol A and a propylene oxide adduct of bisphenol A; and glycerin. From the viewpoint of crack resistance during molding, one or more selected from the group consisting of alkylene glycols and polyoxyalkylene polyols are preferred, polyoxyalkylene glycols are more preferred, and one or more selected from diethylene glycol, dipropylene glycol, and triethylene glycol are even more preferred. In particular, from the viewpoint of improving the durability of molded products, it is preferable to use polyoxyethylene glycol and polyoxypropylene glycol in combination, and it is even more preferable to use diethylene glycol and dipropylene glycol in combination. The content ratio (molar ratio) of polyoxyethylene glycol to polyoxypropylene glycol or the content ratio (molar ratio) of diethylene glycol to dipropylene glycol is not particularly limited, but from the viewpoint of improving durability, it is preferably 40:60 to 80:20, more preferably 50:50 to 70:30, even more preferably 55:45 to 65:35, and particularly preferably 58:42 to 63:37. The polyhydric alcohols may be used alone or in combination of two or more types.

[0028] The saturated polybasic acid is not particularly limited as long as it is a compound having no ethylenically unsaturated bond and two or more carboxy groups or an acid anhydride thereof, and known compounds can be used. The saturated polybasic acid is preferably a saturated dibasic acid. Examples of the saturated polybasic acid include aromatic saturated polybasic acids or acid anhydrides thereof such as phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, nitrophthalic acid, and halogenated phthalic anhydride; aliphatic saturated polybasic acids such as succinic acid, adipic acid, sebacic acid, oxalic acid, malonic acid, azelaic acid, and glutaric acid; and acid anhydrides of cyclic aliphatic saturated polybasic acids such as hexahydrophthalic anhydride. The aromatic saturated polybasic acid or its acid anhydride is preferably one or more selected from the group consisting of aromatic saturated dibasic acids and their acid anhydrides, more preferably one or more selected from phthalic acid, phthalic anhydride, isophthalic acid, and terephthalic acid, and even more preferably one or more selected from isophthalic acid and terephthalic acid. The aliphatic saturated polybasic acid is preferably an aliphatic saturated dibasic acid, more preferably an aliphatic saturated dibasic acid having 4 to 10 carbon atoms, and even more preferably one or more selected from succinic acid, adipic acid, and sebacic acid. From the viewpoint of crack resistance during molding, it is preferable to use one or more selected from the group consisting of aromatic saturated polybasic acids, their acid anhydrides, and aliphatic saturated polybasic acids, and it is more preferable to use an aromatic saturated polybasic acid or its acid anhydride in combination with an aliphatic saturated polybasic acid, and it is even more preferable to use one or more selected from isophthalic acid and terephthalic acid in combination with one or more selected from succinic acid, adipic acid, and sebacic acid. The saturated polybasic acids may be used alone or in combination of two or more kinds.

[0029] When an aromatic saturated polybasic acid or its acid anhydride is used in combination with an aliphatic saturated polybasic acid, the proportion of the aromatic saturated polybasic acid or its acid anhydride relative to the total is preferably 20 mol% or more, more preferably 30 mol% or more, and even more preferably 40 mol% or more. When an aromatic saturated polybasic acid or its acid anhydride is used in combination with an aliphatic saturated polybasic acid, the proportion of the aromatic saturated polybasic acid or its acid anhydride relative to the total is preferably 80 mol% or less, more preferably 70 mol% or less, and even more preferably 60 mol% or less. If the proportion of the aromatic saturated polybasic acid or its acid anhydride is within the above range, the moldability is better and the properties of the cured product can be further improved.

[0030] When an aromatic saturated polybasic acid or its acid anhydride is used in combination with an aliphatic saturated polybasic acid, the proportion of the aliphatic saturated polybasic acid relative to the total is preferably 20 mol% or more, more preferably 30 mol% or more, and even more preferably 40 mol% or more.When an aromatic saturated polybasic acid or its acid anhydride is used in combination with an aliphatic saturated polybasic acid, the proportion of the aliphatic saturated polybasic acid relative to the total is preferably 80 mol% or less, more preferably 70 mol% or less, and even more preferably 60 mol% or less.If the proportion of the aliphatic saturated polybasic acid is within the above range, the crack resistance can be further improved.

[0031] When an aromatic saturated polybasic acid or an acid anhydride thereof and an aliphatic saturated polybasic acid are used in combination, the content ratio (molar ratio) of the structure derived from the aromatic saturated polybasic acid or the acid anhydride thereof to the structure derived from the aliphatic saturated polybasic acid in the saturated polyester resin (A) is preferably 20:80 to 80:20, more preferably 30:70 to 70:30, and even more preferably 40:60 to 60:40.

[0032] When an aromatic saturated polybasic acid or its acid anhydride and an aliphatic saturated polybasic acid are used in combination, the structures derived therefrom may be uniformly dispersed throughout the molecules of the (A) saturated polyester resin, or each may be unevenly distributed within the molecules. From the viewpoint of crack resistance during molding, the (A) saturated polyester resin preferably contains a block (X) that is a polycondensate of a diol and an aromatic saturated polybasic acid or its acid anhydride, the block (X) having a weight-average molecular weight of 3,000 to 5,000, and a block (Y) that is a polycondensate of a diol and an aliphatic saturated polybasic acid. In the (A) saturated polyester resin containing the block (X) and the block (Y), the molar ratio of the structure derived from the aromatic saturated polybasic acid or its acid anhydride to the structure derived from the aliphatic saturated polybasic acid is preferably 20:80 to 80:20, more preferably 30:70 to 70:30, and even more preferably 40:60 to 60:40.

[0033] In the saturated polyester resin (A) containing the block (X) and the block (Y), a structure derived from an aromatic saturated polybasic acid or an acid anhydride thereof may be interspersed in portions other than the block (X) and the block (Y).

[0034] The weight-average molecular weight of block (X) is preferably at least 3000, more preferably at least 3500. The weight-average molecular weight of block (X) is preferably at most 5000, more preferably at most 4500. When the weight-average molecular weight of block (X) is within the above range, crack resistance during molding is better.

[0035] The aromatic saturated polybasic acid or acid anhydride thereof constituting the block (X) is preferably one or more selected from the group consisting of aromatic saturated dibasic acids and acid anhydrides thereof, more preferably one or more selected from phthalic acid, phthalic anhydride, isophthalic acid, and terephthalic acid, and even more preferably one or more selected from isophthalic acid and terephthalic acid.

[0036] The aliphatic saturated polybasic acid constituting the block (Y) is preferably an aliphatic saturated dibasic acid, more preferably an aliphatic saturated dibasic acid having 4 to 10 carbon atoms, and even more preferably one or more selected from succinic acid, adipic acid, and sebacic acid.

[0037] A preferred combination of polyhydric alcohol and saturated polybasic acid is a diol and a saturated dibasic acid, more preferably a polyoxyalkylene glycol and a saturated dibasic acid. More specifically, for example, a combination of diethylene glycol and isophthalic acid, a combination of diethylene glycol and adipic acid, a combination of dipropylene glycol and isophthalic acid, a combination of dipropylene glycol and adipic acid, a combination of diethylene glycol, isophthalic acid and adipic acid, a combination of dipropylene glycol, isophthalic acid and adipic acid, a combination of diethylene glycol, dipropylene glycol, isophthalic acid and adipic acid, a combination of diethylene glycol, dipropylene glycol, isophthalic acid and adipic acid, etc. Among them, the combination of diethylene glycol, isophthalic acid and adipic acid, the combination of dipropylene glycol, isophthalic acid and adipic acid, and the combination of diethylene glycol, dipropylene glycol, isophthalic acid and adipic acid are particularly preferable because of their excellent crack resistance during molding.

[0038] The weight-average molecular weight of the (A) saturated polyester resin is preferably 9,500 or more, more preferably 9,800 or more, and even more preferably 10,000 or more. The weight-average molecular weight of the (A) saturated polyester resin is preferably 13,500 or less, more preferably 13,000 or less, and even more preferably 12,500 or less. When the weight-average molecular weight is within the above range, cracking during molding is further suppressed. Without being bound by any theory, it is believed that by setting the weight-average molecular weight of the (A) saturated polyester resin within the above range, compatibility with the (B) unsaturated polyester resin and dispersibility of the (C) to (F) components are improved, thereby further suppressing cracking during molding. The weight-average molecular weight of the (A) saturated polyester resin can be adjusted by the reaction time during synthesis of the (A) saturated polyester resin. Specifically, the longer the reaction time, the higher the weight-average molecular weight, and the shorter the reaction time, the lower the weight-average molecular weight.

[0039] The content of the (A) saturated polyester resin in the thermosetting resin composition is preferably 5 parts by mass or more, more preferably 8 parts by mass or more, and even more preferably 10 parts by mass or more, based on 100 parts by mass of the total amount of the (B) unsaturated polyester resin and the (C) ethylenically unsaturated monomer. The content of the (A) saturated polyester resin in the thermosetting resin composition is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less, based on 100 parts by mass of the total amount of the (B) unsaturated polyester resin and the (C) ethylenically unsaturated monomer. The content of the (A) saturated polyester resin in the thermosetting resin composition is preferably 5 to 30 parts by mass, more preferably 8 to 25 parts by mass, and even more preferably 10 to 20 parts by mass, based on 100 parts by mass of the total amount of the (B) unsaturated polyester resin and the (C) ethylenically unsaturated monomer. If the content of the (A) saturated polyester resin in the thermosetting resin composition is 5 parts by mass or more, the occurrence of cracks during molding can be further suppressed. When the content of the saturated polyester resin (A) in the thermosetting resin composition is 30 parts by mass or less, the moldability of the thermosetting resin composition and the mechanical properties of the cured product are better.

[0040] (Method for synthesizing (A) saturated polyester resin) The (A) saturated polyester resin can be synthesized by a known method using the above-mentioned raw materials. Various conditions for synthesizing the (A) saturated polyester resin are appropriately set depending on the raw materials used and their amounts.

[0041] Generally, the esterification reaction can be carried out in a stream of an inert gas such as nitrogen gas at a temperature of 140°C to 230°C under pressure or reduced pressure. In the esterification reaction, an esterification catalyst can be used as needed. Examples of the esterification catalyst include known catalysts such as manganese acetate, dibutyltin oxide, stannous oxalate, zinc acetate, and cobalt acetate. The esterification catalysts may be used alone or in combination of two or more.

[0042] The equivalent weight of the hydroxyl groups of the polyhydric alcohol relative to the total amount of carboxyl groups of the saturated polybasic acid is preferably in the range of 0.9 to 1.2.

[0043] When an aromatic saturated polybasic acid or an acid anhydride thereof and an aliphatic saturated polybasic acid are used in combination, the structures derived therefrom may be uniformly dispersed in the molecules of the saturated polyester resin (A). Such a saturated polyester resin (A) can be obtained by adding both of them to a reaction vessel at the same time and carrying out an esterification reaction.

[0044] From the viewpoint of crack resistance during molding, it is preferable that the structure derived from the aromatic saturated polybasic acid or its acid anhydride and the structure derived from the aliphatic saturated polybasic acid are unevenly distributed in the molecule. Such a saturated polyester resin (A) can be obtained by first charging one of the saturated polybasic acids into a reaction vessel, proceeding with the esterification reaction until a certain amount of the saturated polybasic acid is consumed, then charging the other saturated polybasic acid into the reaction vessel, and proceeding with the esterification reaction until a desired weight-average molecular weight is obtained. For example, such a saturated polyester resin (A) can be synthesized as follows: first, a polyhydric alcohol equivalent to the total amount of the aromatic saturated polybasic acid or its acid anhydride and the aliphatic saturated polybasic acid and the aromatic saturated polybasic acid or its acid anhydride are charged into the reaction vessel, and the esterification reaction is proceeded until a certain amount of the aromatic saturated polybasic acid or its acid anhydride is consumed, then charging the aliphatic saturated polybasic acid into the reaction vessel, and proceeding with the esterification reaction.

[0045] The saturated polyester resin (A) containing block (X) which is a polycondensate of a diol and an aromatic saturated polybasic acid or an acid anhydride thereof, and block (Y) which is a polycondensate of a diol and an aliphatic saturated polybasic acid, can be synthesized, for example, as follows: a diol and an aromatic saturated polybasic acid or an acid anhydride thereof in amounts equivalent to the total amount of the aromatic saturated polybasic acid or an acid anhydride thereof and the aliphatic saturated polybasic acid are first charged into a reaction vessel, and an esterification reaction is allowed to proceed until a certain amount of the aromatic saturated polybasic acid or an acid anhydride thereof has been consumed. Then, an aliphatic saturated polybasic acid is charged into the reaction vessel, and the esterification reaction is allowed to proceed.

[0046] The weight-average molecular weight of block (X) can be adjusted by adjusting the timing of adding the subsequently added aliphatic saturated polybasic acid. For example, the acid value of the reaction solution, i.e., the remaining amount of the previously added aromatic saturated polybasic acid or its acid anhydride, can be traced, and the aliphatic saturated polybasic acid can be added when the remaining amount reaches the desired amount. From the viewpoint of crack resistance, the acid value of the reaction solution when the aliphatic saturated polybasic acid is added is preferably 30 KOHmg / g or less, more preferably 20 KOHmg / g or less, and even more preferably 10 KOHmg / g or less. The acid value of the reaction solution when the aliphatic saturated polybasic acid is added may be 1 KOHmg / g or more, 3 KOHmg / g or more, or 5 KOHmg / g or more.

[0047] [(B) Unsaturated Polyester Resin] The (B) unsaturated polyester resin is a polycondensate of a polyhydric alcohol and an unsaturated polybasic acid, or a polycondensate of a polyhydric alcohol, an unsaturated polybasic acid, and a saturated polybasic acid. The (B) unsaturated polyester resin contains at least an unsaturated polyester resin (B-1), which is a polycondensate of a mixture containing a diol and an unsaturated polybasic acid, and which contains a structure derived from propylene glycol and a structure derived from neopentyl glycol. The (B) unsaturated polyester resin may further contain an unsaturated polyester resin (B-2), which is a polycondensate of a mixture containing a diol and an unsaturated polybasic acid, and which contains a structure derived from propylene glycol but does not contain a structure derived from neopentyl glycol. The unsaturated polyester resin (B) may contain an unsaturated polyester resin other than (B-1) and (B-2). By using the unsaturated polyester resin (B), a cured product having excellent mechanical strength and heat resistance can be obtained.

[0048] In the present disclosure, styrene monomers and the like contained in commercially available unsaturated polyester resins are classified as (C) ethylenically unsaturated monomers.

[0049] The content of the (B-1) unsaturated polyester resin in the (B) unsaturated polyester resin is preferably 75% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more. When the content of the (B-1) unsaturated polyester resin is 75% by mass or more, appropriate moldability, flowability, and cure shrinkage can be ensured. There is no particular upper limit for the content of the (B-1) unsaturated polyester resin in the (B) unsaturated polyester resin. For example, it may be 100% by mass, 97% by mass, or 95% by mass.

[0050] When the (B-1) unsaturated polyester resin and the (B-2) unsaturated polyester resin are used in combination, the total content of the (B-1) unsaturated polyester resin and the (B-2) unsaturated polyester resin in the (B) unsaturated polyester resin is preferably 75% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more. When the total content of the (B-1) unsaturated polyester resin and the (B-2) unsaturated polyester resin is 75% by mass or more, appropriate moldability, fluidity, and cure shrinkage can be ensured. There is no particular upper limit to the total content of the (B-1) unsaturated polyester resin and the (B-2) unsaturated polyester resin in the (B) unsaturated polyester resin. For example, it may be 100% by mass, 97% by mass, or 95% by mass.

[0051] When the unsaturated polyester resin (B-1) and the unsaturated polyester resin (B-2) are used in combination, the proportion of the unsaturated polyester resin (B-1) relative to the total of the unsaturated polyester resin (B-1) and the unsaturated polyester resin (B-2) is preferably 20 to 80% by mass, more preferably 30 to 70% by mass, and even more preferably 40 to 60% by mass.

[0052] In another embodiment, the content of the unsaturated polyester resin (B-1) in the unsaturated polyester resin (B) is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more. The content of the unsaturated polyester resin (B-1) in the unsaturated polyester resin (B) is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less. The content of the unsaturated polyester resin (B-2) in the unsaturated polyester resin (B) is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more. The content of the unsaturated polyester resin (B-2) in the unsaturated polyester resin (B) is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less.

[0053] The weight-average molecular weight of the (B) unsaturated polyester resin is preferably 2,000 to 50,000, more preferably 5,000 to 50,000, even more preferably 10,000 to 50,000, and even more preferably 13,000 to 35,000. When the weight-average molecular weight is within the above range, cracking during molding is further suppressed. Without being bound by any theory, it is believed that by setting the weight-average molecular weight of the (B) unsaturated polyester resin within the above range, compatibility with the (A) saturated polyester resin and dispersibility of the (C) to (F) components are improved, thereby further suppressing cracking during molding. The weight-average molecular weight of the (B) unsaturated polyester resin refers to the weight-average molecular weight of the resin before curing.

[0054] The content of the (B) unsaturated polyester resin in the thermosetting resin composition is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, and even more preferably 40 parts by mass or more, based on 100 parts by mass of the total amount of the (B) unsaturated polyester resin and the (C) ethylenically unsaturated monomer. The content of the (B) unsaturated polyester resin in the thermosetting resin composition is preferably 80 parts by mass or less, more preferably 70 parts by mass or less, and even more preferably 60 parts by mass or less, based on 100 parts by mass of the total amount of the (B) unsaturated polyester resin and the (C) ethylenically unsaturated monomer. When the content of the (B) unsaturated polyester resin in the thermosetting resin composition is 20 parts by mass or more, the mechanical strength of the cured product is good. When the content of the (B) unsaturated polyester resin in the thermosetting resin composition is 80 parts by mass or less, the viscosity of the thermosetting resin composition can be adjusted to an appropriate range, and the moldability is good.

[0055] <(B-1) Unsaturated Polyester Resin> The (B-1) unsaturated polyester resin is a polycondensate of a mixture containing a diol and an unsaturated polybasic acid, and contains a structure derived from propylene glycol and a structure derived from neopentyl glycol. The (B-1) unsaturated polyester resin may contain a structure derived from a saturated polybasic acid. The (B-1) unsaturated polyester resin may contain a structure derived from a diol other than propylene glycol and neopentyl glycol.

[0056] The unsaturated polyester resin (B-1) may be used alone or in combination of two or more. By using the unsaturated polyester resin (B-1), a cured product having excellent mechanical strength and heat resistance can be obtained.

[0057] Examples of other diols other than propylene glycol and neopentyl glycol include alkylene glycols such as ethylene glycol, butanediol, pentanediol, hexanediol, 2-methyl-1,3-propanediol, 1,4-cyclohexanedimethanol, and hydrogenated bisphenol A; polyoxyalkylene glycols such as diethylene glycol, dipropylene glycol, triethylene glycol, tetraethylene glycol, and polyethylene glycol; bisphenol A; and alkylene oxide-modified bisphenol A such as an ethylene oxide adduct of bisphenol A and a propylene oxide adduct of bisphenol A. From the viewpoint of crack resistance during molding, alkylene glycols are preferred, alkylene glycols having 2 to 6 carbon atoms are more preferred, and one or more selected from ethylene glycol, butanediol, pentanediol, and hexanediol are even more preferred. From the viewpoint of chemical resistance, hydrogenated bisphenol A is preferred. The other diols may be used alone or in combination of two or more.

[0058] In the unsaturated polyester resin (B-1), the content ratio (molar ratio) of the structure derived from propylene glycol to the structure derived from neopentyl glycol is preferably 10:90 to 90:10, more preferably 15:85 to 85:15, and even more preferably 20:80 to 80:20.

[0059] Among the diol-derived structures of the (B-1) unsaturated polyester resin, the propylene glycol-derived structure is preferably 10 mol % or more, more preferably 20 mol % or more, and even more preferably 30 mol % or more. Among the diol-derived structures of the (B-1) unsaturated polyester resin, the propylene glycol-derived structure is preferably 90 mol % or less, more preferably 85 mol % or less, and even more preferably 80 mol % or less.

[0060] Of the diol-derived structures of the (B-1) unsaturated polyester resin, the neopentyl glycol-derived structure is preferably 10 mol % or more, more preferably 15 mol % or more, and even more preferably 20 mol % or more. Of the diol-derived structures of the (B-1) unsaturated polyester resin, the neopentyl glycol-derived structure is preferably 90 mol % or less, more preferably 80 mol % or less, and even more preferably 70 mol % or less.

[0061] Among the diol-derived structures of the (B-1) unsaturated polyester resin, the total proportion of propylene glycol-derived structures and neopentyl glycol-derived structures is preferably 70 mol% or more, more preferably 75 mol% or more, and even more preferably 80 mol% or more. Among the diol-derived structures of the (B-1) unsaturated polyester resin, the total proportion of propylene glycol-derived structures and neopentyl glycol-derived structures may be 100 mol% or less, 95 mol% or less, or 90 mol% or less.

[0062] Among the diol-derived structures of the (B-1) unsaturated polyester resin, the structure derived from other diols may be 0 mol% or more, preferably 5 mol% or more, and more preferably 10 mol% or more. Among the diol-derived structures of the (B-1) unsaturated polyester resin, the structure derived from other diols is preferably 30 mol% or less, more preferably 25 mol% or less, and even more preferably 20 mol% or less.

[0063] The (B-1) unsaturated polyester resin may contain a structure derived from a polyhydric alcohol having three or more hydroxyl groups. An example of a polyhydric alcohol having three or more hydroxyl groups is glycerin. Among the structures of the (B-1) unsaturated polyester resin derived from a polyhydric alcohol having two or more hydroxyl groups, the structure derived from a diol is preferably 95 mol % or more, more preferably 98 mol % or more, and even more preferably 100 mol %. Among the structures of the (B-1) unsaturated polyester resin derived from a polyhydric alcohol having two or more hydroxyl groups, the upper limit of the structure derived from a diol may be 100 mol % or 99 mol %.

[0064] The unsaturated polybasic acid is not particularly limited as long as it is a compound having an ethylenically unsaturated bond and two or more carboxy groups, or an acid anhydride thereof, and known compounds can be used. Unsaturated polybasic acids having 4 to 6 carbon atoms or acid anhydrides thereof are particularly preferred because they are less expensive and produce thermosetting resin compositions with superior mechanical strength and heat resistance in cured products. The unsaturated polybasic acid is preferably an unsaturated dibasic acid. Examples of unsaturated polybasic acids include maleic acid, maleic anhydride, fumaric acid, citraconic acid, itaconic acid, and chloromaleic acid. More preferred are one or more selected from fumaric acid, maleic acid, maleic anhydride, and itaconic acid, and even more preferred are one or more selected from fumaric acid and maleic anhydride. The unsaturated polybasic acids may be used alone or in combination.

[0065] The saturated polybasic acid is not particularly limited as long as it is a compound having no ethylenically unsaturated bond and two or more carboxy groups or an acid anhydride thereof, and known compounds can be used. Examples of saturated polybasic acids include aromatic saturated polybasic acids or acid anhydrides thereof such as phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, nitrophthalic acid, and halogenated phthalic anhydride; aliphatic saturated polybasic acids such as succinic acid, adipic acid, sebacic acid, oxalic acid, malonic acid, azelaic acid, and glutaric acid; and acid anhydrides of cyclic aliphatic saturated polybasic acids such as hexahydrophthalic anhydride. The saturated polybasic acids may be used alone or in combination of two or more.

[0066] The weight-average molecular weight of the (B-1) unsaturated polyester resin is not particularly limited. The weight-average molecular weight of the (B-1) unsaturated polyester resin is preferably 2,000 or more, more preferably 5,000 or more, even more preferably 10,000 or more, and particularly preferably 13,000 or more. The weight-average molecular weight of the (B-1) unsaturated polyester resin is preferably 50,000 or less, more preferably 35,000 or less. The weight-average molecular weight of the (B-1) unsaturated polyester resin is preferably 2,000 to 50,000, more preferably 5,000 to 50,000, even more preferably 10,000 to 50,000, and particularly preferably 13,000 to 35,000. A weight-average molecular weight of 2,000 to 50,000 further improves the moldability of the thermosetting resin composition. If the weight-average molecular weight is 2,000 to 50,000, the occurrence of cracks during molding is further suppressed. Without being bound by any theory, it is thought that by setting the weight-average molecular weight of the unsaturated polyester resin (B-1) within the above range, the compatibility with the saturated polyester resin (A) and the dispersibility of the components (C) to (F) are improved, and the occurrence of cracks during molding is further suppressed.

[0067] The degree of unsaturation of the unsaturated polyester resin (B-1) is preferably 50 to 100 mol %, more preferably 60 to 100 mol %, and even more preferably 70 to 100 mol %. When the degree of unsaturation is within the above range, the moldability of the thermosetting resin composition containing the unsaturated polyester resin (B-1) is improved.

[0068] The degree of unsaturation of the unsaturated polyester resin can be calculated using the number of moles of the unsaturated polybasic acid and saturated polybasic acid used as raw materials according to the following formula: Unsaturation degree (mol %) = {(number of moles of unsaturated polybasic acid × number of ethylenically unsaturated bonds per molecule of unsaturated polybasic acid) / (number of moles of unsaturated polybasic acid + number of moles of saturated polybasic acid)} × 100

[0069] <Unsaturated Polyester Resin (B-2)> The (B-2) unsaturated polyester resin is a polycondensate of a mixture containing a diol and an unsaturated polybasic acid, and contains a structure derived from propylene glycol but does not contain a structure derived from neopentyl glycol. The (B-2) unsaturated polyester resin may contain a structure derived from a saturated polybasic acid. The (B-2) unsaturated polyester resin may contain a structure derived from a diol other than propylene glycol and neopentyl glycol.

[0070] The unsaturated polyester resin (B-2) may be used alone or in combination of two or more thereof. By using the unsaturated polyester resin (B-2), the shrinkage rate during molding can be adjusted.

[0071] Specific examples and preferred examples of the other diols other than propylene glycol and neopentyl glycol are the same as those for the unsaturated polyester resin (B-1). The other diols may be used alone or in combination of two or more.

[0072] Among the diol-derived structures of the (B-2) unsaturated polyester resin, the propylene glycol-derived structure is preferably 30 mol% or more, more preferably 50 mol% or more, and even more preferably 70 mol% or more. Among the diol-derived structures of the (B-2) unsaturated polyester resin, the propylene glycol-derived structure may be 100 mol% or less, 90 mol% or less, or 80 mol% or less.

[0073] In the diol-derived structures of the (B-2) unsaturated polyester resin, the structure derived from other diols may be 0 mol % or more, 3 mol % or more, or 5 mol % or more. In the diol-derived structures of the (B-2) unsaturated polyester resin, the structure derived from other diols is preferably 30 mol % or less, more preferably 20 mol % or less, and even more preferably 10 mol % or less.

[0074] The (B-2) unsaturated polyester resin may contain a structure derived from a polyhydric alcohol having three or more hydroxyl groups. An example of a polyhydric alcohol having three or more hydroxyl groups is glycerin. Among the structures of the (B-2) unsaturated polyester resin derived from a polyhydric alcohol having two or more hydroxyl groups, the structure derived from a diol is preferably 95 mol% or more, more preferably 98 mol% or more, and even more preferably 100 mol%. Among the structures of the (B-2) unsaturated polyester resin derived from a polyhydric alcohol having two or more hydroxyl groups, the upper limit of the structure derived from a diol may be 100 mol% or 99 mol%.

[0075] Specific examples and preferred examples of the unsaturated polybasic acid are the same as those of the unsaturated polyester resin (B-1). The unsaturated polybasic acid may be used alone or in combination of two or more kinds.

[0076] Specific examples and preferred examples of the saturated polybasic acid are the same as those of the unsaturated polyester resin (B-1). The saturated polybasic acid may be used alone or in combination of two or more kinds.

[0077] The weight-average molecular weight of the (B-2) unsaturated polyester resin is not particularly limited. The weight-average molecular weight of the (B-2) unsaturated polyester resin is preferably 2,000 to 50,000, more preferably 5,000 to 50,000, even more preferably 10,000 to 50,000, and even more preferably 13,000 to 35,000. A weight-average molecular weight of 2,000 to 50,000 further improves the moldability of the thermosetting resin composition. A weight-average molecular weight of 2,000 to 50,000 further suppresses cracking during molding. Without being bound by any theory, it is believed that by setting the weight-average molecular weight of the (B-2) unsaturated polyester resin within the above range, compatibility with the (A) saturated polyester resin and dispersibility of the (C) to (F) components are improved, thereby further suppressing cracking during molding.

[0078] The degree of unsaturation of the unsaturated polyester resin (B-2) is preferably 50 to 100 mol %, more preferably 60 to 100 mol %, and even more preferably 70 to 100 mol %. When the degree of unsaturation is within the above range, the moldability of the thermosetting resin composition containing the unsaturated polyester resin (B-2) is improved.

[0079] (Method for synthesizing (B) unsaturated polyester resin) The (B) unsaturated polyester resin can be synthesized by a known method using the above-mentioned raw materials. Various conditions for synthesizing the (B) unsaturated polyester resin are appropriately set depending on the raw materials used and their amounts.

[0080] Generally, the esterification reaction can be carried out in a stream of an inert gas such as nitrogen gas at a temperature of 140°C to 230°C under pressure or reduced pressure. In the esterification reaction, an esterification catalyst can be used as needed. Examples of the esterification catalyst include known catalysts such as manganese acetate, dibutyltin oxide, stannous oxalate, zinc acetate, and cobalt acetate. The esterification catalysts may be used alone or in combination of two or more.

[0081] In order to increase the molecular weight by improving the reaction rate, it is preferable that the equivalent weight of the hydroxyl groups of the polyhydric alcohol is in the range of 0.9 to 1.2 relative to the total amount of carboxyl groups of the unsaturated polybasic acid and any saturated polybasic acid.

[0082] [(C) Ethylenically Unsaturated Monomer] The (C) ethylenically unsaturated monomer is not particularly limited as long as it is a monomer having an ethylenically unsaturated bond. The (C) ethylenically unsaturated monomer may be used alone or in combination of two or more kinds.

[0083] Specific examples include vinyl compounds such as styrene, vinyltoluene, t-butylstyrene, methoxystyrene, divinylbenzene, and vinylnaphthalene; methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, furfuryl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, phenyl (meth)acrylate, and benzyl (meth)acrylate. (meth)acrylates such as acrylate, phenoxyethyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, allyl (meth)acrylate, isobornyl (meth)acrylate, acetoacetoxyethyl (meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, tricyclodecanol di(meth)acrylate, and trimethylolpropane tri(meth)acrylate; and cyclic unsaturated compounds such as acenaphthylene and norbornene. From the viewpoint of copolymerizability with the (B) unsaturated polyester resin, vinyl compounds are preferred, and one or more selected from styrene, vinyltoluene, t-butylstyrene, and methoxystyrene are more preferred, with styrene being even more preferred.

[0084] The content of the (C) ethylenically unsaturated monomer in the thermosetting resin composition is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, and even more preferably 40 parts by mass or more, based on 100 parts by mass of the total amount of the (B) unsaturated polyester resin and the (C) ethylenically unsaturated monomer. The content of the (C) ethylenically unsaturated monomer in the thermosetting resin composition is preferably 80 parts by mass or less, more preferably 70 parts by mass or less, and even more preferably 60 parts by mass or less, based on 100 parts by mass of the total amount of the (B) unsaturated polyester resin and the (C) ethylenically unsaturated monomer. When the content of the (C) ethylenically unsaturated monomer in the thermosetting resin composition is 20 parts by mass or more, the viscosity of the thermosetting resin composition can be adjusted within an appropriate range, and the moldability is good. When the content of the (C) ethylenically unsaturated monomer in the thermosetting resin composition is 80 parts by mass or less, the mechanical strength of the cured product is good.

[0085] [(D) Thermal Polymerization Initiator] The (D) thermal polymerization initiator is not particularly limited as long as it is a polymerization initiator that generates radicals upon heating. Examples thereof include organic peroxides such as diacyl peroxides, peroxyesters, hydroperoxides, dialkyl peroxides, ketone peroxides, peroxyketals, alkyl peresters, and percarbonates.

[0086] Among these organic peroxides, the preferred thermal polymerization initiator (D) is 1,1-di-t-hexylperoxycyclohexane, t-hexylperoxyisopropyl carbonate, t-butylperoxyoctoate, t-butylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-amylperoxy-2-ethylhexanoate, benzoyl peroxide, 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, t-butylperoxyisopropyl carbonate, t-butylperoxybenzoate, dicumyl peroxide, and di-t-butyl peroxide. The thermal polymerization initiator (D) may be used alone or in combination of two or more.

[0087] The content of the (D) thermal polymerization initiator in the thermosetting resin composition is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 3 parts by mass or more, based on 100 parts by mass of the total amount of the (B) unsaturated polyester resin and the (C) ethylenically unsaturated monomer. The content of the (D) thermal polymerization initiator in the thermosetting resin composition is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less, based on 100 parts by mass of the total amount of the (B) unsaturated polyester resin and the (C) ethylenically unsaturated monomer. When the content of the (D) thermal polymerization initiator in the thermosetting resin composition is 0.5 parts by mass or more, the curing reaction during molding of the thermosetting resin composition proceeds uniformly, resulting in good physical properties and appearance of the cured product. When the content of the (D) thermal polymerization initiator in the thermosetting resin composition is 20 parts by mass or less, the storage stability of the thermosetting resin composition is good and handling is improved.

[0088] [(E) Glass Fiber] The (E) glass fiber is not particularly limited as long as it is a fibrous substance having an aspect ratio of at least 3. Specific examples include chopped strand glass.

[0089] The fiber length of the (E) glass fiber is preferably 20 mm or less, more preferably 10 mm or less, and even more preferably 5 mm or less. When the fiber length is 20 mm or less, the moldability of the thermosetting resin composition is good, and the appearance of the cured product is good. The fiber length is preferably 0.1 mm or more, more preferably 0.5 mm or more, and even more preferably 1 mm or more. When the fiber length is 0.1 mm or more, the strength of the cured product is good. The average fiber diameter of the (E) glass fiber is preferably 3 to 100 μm, and more preferably 5 to 30 μm.

[0090] The content of the (E) glass fiber in the thermosetting resin composition is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 20 parts by mass or more, based on 100 parts by mass of the total amount of the (B) unsaturated polyester resin and the (C) ethylenically unsaturated monomer. The content of the (E) glass fiber in the thermosetting resin composition is preferably 150 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 50 parts by mass or less, based on 100 parts by mass of the total amount of the (B) unsaturated polyester resin and the (C) ethylenically unsaturated monomer. When the content of the (E) glass fiber in the thermosetting resin composition is 5 parts by mass or more, the mechanical properties of the cured product obtained from the thermosetting resin composition are better. When the content of the (E) glass fiber in the thermosetting resin composition is 150 parts by mass or less, the (E) glass fiber is more uniformly dispersed in the thermosetting resin composition, allowing for the production of a homogeneous cured product.

[0091] [(F) Inorganic Filler] As the (F) inorganic filler, a particulate material known in the technical field of the present invention can be used. The use of the (F) inorganic filler can reduce the molding shrinkage of the molded article, adjust the viscosity of the thermosetting resin composition to improve workability, or improve the strength of the molded article.

[0092] Examples of (F) inorganic fillers include calcium carbonate, silica, aluminum oxide, aluminum hydroxide, barium sulfate, calcium sulfate, calcium hydroxide, calcium oxide, magnesium oxide, magnesium hydroxide, wollastonite, clay, kaolin, mica, gypsum, silicic anhydride, and glass powder. Calcium carbonate, aluminum oxide, and aluminum hydroxide are preferred because they are inexpensive. (F) inorganic fillers may be used alone or in combination of two or more.

[0093] The average particle size of the (F) inorganic filler is preferably 1 to 100 μm, more preferably 1 to 60 μm, and even more preferably 1 to 50 μm. If the average particle size of the (F) inorganic filler is 1 μm or more, particle aggregation can be suppressed. On the other hand, if the average particle size of the (F) inorganic filler is 100 μm or less, the moldability of the thermosetting resin composition is good.

[0094] In this specification, the term "average particle size" refers to the 50% particle size (D50) in the volume-based cumulative particle size distribution measured using a laser diffraction / scattering particle size distribution analyzer (Microtrac Bell Co., Ltd., FRA).

[0095] The shape of the inorganic filler (F) is not particularly limited, and examples thereof include substantially spherical, ellipsoidal, scaly, and amorphous shapes.

[0096] The content of the (F) inorganic filler in the thermosetting resin composition is preferably 50 parts by mass or more, more preferably 100 parts by mass or more, and even more preferably 200 parts by mass or more, based on 100 parts by mass of the total amount of the (B) unsaturated polyester resin and the (C) ethylenically unsaturated monomer. The content of the (F) inorganic filler in the thermosetting resin composition is preferably 1000 parts by mass or less, more preferably 800 parts by mass or less, and even more preferably 500 parts by mass or less, based on 100 parts by mass of the total amount of the (B) unsaturated polyester resin and the (C) ethylenically unsaturated monomer. If the content of the (F) inorganic filler in the thermosetting resin composition is 50 parts by mass or more, the mechanical properties of the cured product are better. If the content of the (F) inorganic filler in the thermosetting resin composition is 1000 parts by mass or less, the (F) inorganic filler is more uniformly dispersed in the thermosetting resin composition, and a homogeneous cured product can be produced.

[0097] [(G) Other Low-Profile Agents] The thermosetting resin composition may contain (G) other low-profile agents other than the saturated polyester resin, as needed. The (G) other low-profile agents are not particularly limited, and any known low-profile agents in the technical field of the present invention can be used. As the (G) other low-profile agents, thermoplastic resins are preferred. Examples of the (G) other low-profile agents include polystyrene, polyethylene, polymethyl methacrylate, polyvinyl acetate, polycaprolactone, and styrene-butadiene rubber. Of these, polystyrene is preferred from the viewpoint of reducing the shrinkage rate of the cured product. The (G) other low-profile agents may be used alone or in combination of two or more.

[0098] The content of the (G) other low-shrinkage agent in the thermosetting resin composition may be 1 part by mass or more, 3 parts by mass or more, or 5 parts by mass or more, based on 100 parts by mass of the total amount of the (B) unsaturated polyester resin and the (C) ethylenically unsaturated monomer. The content of the (G) other low-shrinkage agent in the thermosetting resin composition may be 30 parts by mass or less, 20 parts by mass or less, or 10 parts by mass or less, based on 100 parts by mass of the total amount of the (B) unsaturated polyester resin and the (C) ethylenically unsaturated monomer. When the content of the (G) other low-shrinkage agent in the thermosetting resin composition is 1 part by mass or more, the shrinkage rate of the cured product is small, and the desired dimensional accuracy can be obtained in the molded product. When the content of the (G) other low-shrinkage agent in the thermosetting resin composition is 30 parts by mass or less, the moldability of the thermosetting resin composition and the mechanical properties of the cured product are better.

[0099] [(H) Mold Release Agent] The thermosetting resin composition may contain a (H) mold release agent as needed. The (H) mold release agent is not particularly limited, and any agent known in the technical field of the present invention can be used. Examples of the (H) mold release agent include stearic acid, oleic acid, zinc stearate, calcium stearate, aluminum stearate, magnesium stearate, stearic acid amide, oleic acid amide, silicone oil, and synthetic wax. The (H) mold release agent may be used alone or in combination of two or more types.

[0100] When the (H) mold release agent is used, its content is preferably 1 to 40 parts by mass, more preferably 5 to 30 parts by mass, and even more preferably 8 to 20 parts by mass, per 100 parts by mass of the (B) unsaturated polyester resin. If the (H) mold release agent content is 1 part by mass or more, the releasability of the cured product during molding is good, improving productivity of the product. On the other hand, if the (H) mold release agent content is 40 parts by mass or less, excess release agent will not contaminate the surface of the cured product, and a cured product with a good appearance can be obtained.

[0101] [Other Additives] In addition to the above components, the thermosetting resin composition may contain components known in the technical field of the present invention, such as viscosity modifiers such as thickeners and viscosity reducers, colorants, polymerization inhibitors, and molding aids, within the range that does not impair the effects of the present invention.

[0102] The thickener is a compound other than the inorganic filler (F) that exhibits a thickening effect, and examples thereof include isocyanate compounds. The thickener may be used alone or in combination of two or more. The content of the thickener can be appropriately adjusted depending on the handleability, fluidity, etc. required for the thermosetting resin composition.

[0103] A colorant is used when coloring a cured product. Examples of colorants include various dyes, inorganic pigments, and organic pigments. The colorants may be used alone or in combination of two or more. The content of the colorant can be appropriately adjusted depending on the degree of coloration desired in the cured product.

[0104] Examples of polymerization inhibitors include hydroquinone, trimethylhydroquinone, p-benzoquinone, naphthoquinone, t-butylhydroquinone, catechol, p-t-butylcatechol, and 2,6-di-t-butyl-4-methylphenol. The polymerization inhibitors may be used alone or in combination. The content of the polymerization inhibitor can be appropriately adjusted depending on the storage environment, storage period, curing conditions, etc. of the thermosetting resin composition.

[0105] <Method for Producing Thermosetting Resin Composition> The thermosetting resin composition can be produced by mixing (A) a saturated polyester resin, (B) an unsaturated polyester resin, (C) an ethylenically unsaturated monomer, (D) a thermal polymerization initiator, (E) glass fiber, and (F) an inorganic filler, and, as necessary, optional components such as (G) other low-shrinkage agents, (H) a mold release agent, and other additives.

[0106] An example of a mixing method is kneading. The kneading method is not particularly limited, and for example, a kneader, a disperser, a planetary mixer, etc. can be used. The kneading temperature is preferably 5°C to 50°C, more preferably 10°C to 40°C.

[0107] The order in which the components are mixed when producing a thermosetting resin composition is not particularly limited. For example, it is preferable to mix the unsaturated polyester resin (B) with part or all of the ethylenically unsaturated monomer (C) and then mix the other components, since this makes it easier to obtain a thermosetting resin composition in which the components are sufficiently dispersed or uniformly mixed. At least a part of the ethylenically unsaturated monomer (C) may be mixed in advance with the unsaturated polyester resin (B) so that it acts as a solvent, dispersion medium, etc.

[0108] <Method for producing molding material> The molding material can be produced by heating and curing a thermosetting resin composition. The conditions for curing the thermosetting resin composition can be appropriately set depending on the materials used and the decomposition temperature of the (D) thermal polymerization initiator, etc. An example of preferred conditions is a temperature of 120 to 180°C, more preferably a temperature of 120 to 160°C, and a curing time of 1 to 30 minutes.

[0109] <Method for Manufacturing a Molded Stator> A molded stator can be manufactured, for example, by injecting a thermosetting resin composition into a mold in which a stator is placed in a predetermined position, and then heating the composition. The molding method is not particularly limited, and includes methods commonly used in the technical field of the present invention, such as transfer molding and injection molding.

[0110] More specific methods for manufacturing a molded stator include, for example, a method in which a mold is opened, a thermosetting resin composition is poured into the mold with a stator placed therein, and cured; and a method in which a thermosetting resin composition is injected from the outside into a closed mold with a stator placed therein through a hole in the mold, such as a sprue, under reduced pressure inside the mold or with pressure applied from the outside, as in injection molding, and cured. The conditions for curing the thermosetting resin composition in the mold can be set appropriately depending on the material used. An example of a preferred condition is a temperature of 120 to 180°C, more preferably a temperature of 120 to 160°C, and a curing time of 1 to 30 minutes.

[0111] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0112] A synthesis example of (A) saturated polyester resin is shown below.

[0113] The following raw materials were used: Diol: Diethylene glycol (Fujifilm Wako Pure Chemical Corporation) Dipropylene glycol (Fujifilm Wako Pure Chemical Corporation) Saturated polybasic acid: Isophthalic acid (Fujifilm Wako Pure Chemical Corporation) Adipic acid (Fujifilm Wako Pure Chemical Corporation)

[0114] Synthesis Example 1: 50 mol parts of isophthalic acid, 60 mol parts of diethylene glycol, and 40 mol parts of dipropylene glycol were charged into a four-neck flask equipped with a thermometer, a stirrer, an inert gas inlet, and a reflux condenser. The temperature was raised to 210°C while stirring under a nitrogen gas stream, and an esterification reaction was carried out. When the acid value of the reaction solution reached 10 KOH mg / g or less, 50 mol parts of adipic acid was added, and the esterification reaction was continued to obtain a saturated polyester resin. Thereafter, when the acid value of the reaction solution reached 10 KOH mg / g or less, styrene monomer was added in an amount of 40% by mass relative to the total of the saturated polyester resin and the styrene monomer, to obtain a mixture of saturated polyester resin and styrene. The resulting saturated polyester resin had a weight average molecular weight (Mw) of 10,000. The weight average molecular weight (Mw) of the block (X) of the resulting saturated polyester resin was 4,000.

[0115]

[0116] [Synthesis Examples 2 to 5] Mixtures of saturated polyester resin and styrene were obtained in the same manner as in Synthesis Example 1, except for using the compositions shown in Table 1. The weight average molecular weight (Mw) of the saturated polyester resin and the weight average molecular weight (Mw) of the block (X) of the saturated polyester resin are shown in Table 1.

[0117] A synthesis example of the unsaturated polyester resin (B) is shown below.

[0118] The following raw materials were used: Diol: Propylene glycol (FUJIFILM Wako Pure Chemical Corporation) Neopentyl glycol (FUJIFILM Wako Pure Chemical Corporation) Hydrogenated bisphenol A (FUJIFILM Wako Chemical Co., Ltd.) Unsaturated polybasic acid: Maleic anhydride (FUJIFILM Wako Pure Chemical Corporation) Fumaric acid (FUJIFILM Wako Pure Chemical Corporation) Saturated polybasic acid: Isophthalic acid (FUJIFILM Wako Pure Chemical Corporation)

[0119] [Synthesis Example 6] (B-1) Synthesis of Unsaturated Polyester Resin 100 mol parts of maleic anhydride, 60 mol parts of propylene glycol, and 40 mol parts of neopentyl glycol were charged into a four-neck flask equipped with a thermometer, a stirrer, an inert gas inlet, and a reflux condenser. The temperature was raised to 210°C while heating and stirring under a nitrogen gas flow, and an esterification reaction was carried out to obtain an unsaturated polyester resin. Styrene monomer was then added in an amount of 40% by mass relative to the total of the unsaturated polyester resin and the styrene monomer, to obtain a mixture of unsaturated polyester resin and styrene. The resulting unsaturated polyester resin had an unsaturation degree of 100 mol% and a weight average molecular weight (Mw) of 20,000.

[0120]

[0121] [Synthesis Examples 7 and 8] (B-1) Synthesis of Unsaturated Polyester Resin A mixture of unsaturated polyester resin and styrene was obtained in the same manner as in Synthesis Example 6, except for using the composition shown in Table 2. The weight average molecular weight (Mw) of the unsaturated polyester resin is shown in Table 2.

[0122] [Synthesis Examples 9 to 11] (B-2) Synthesis of Unsaturated Polyester Resin A mixture of unsaturated polyester resin and styrene was obtained in the same manner as in Synthesis Example 6, except for using the composition shown in Table 2. The weight average molecular weight (Mw) of the unsaturated polyester resin is shown in Table 2.

[0123] The other components used were as follows:

[0124] (C) Ethylenically unsaturated monomer: Styrene (Idemitsu Kosan Co., Ltd.)

[0125] (D) Thermal polymerization initiator: Perhexyl (trademark) I (t-hexylperoxyisopropyl carbonate, NOF Corporation)

[0126] (E) Glass fiber: Chopped strand ECS-03B173 / P9 (glass chopped, fiber diameter 13 μm, fiber length 3.0 mm, Nippon Electric Glass Co., Ltd.)

[0127] (F) Inorganic filler: Softon 1200 (calcium carbonate, average particle size 1.80 μm, Bihoku Funka Kogyo Co., Ltd.) Calcium hydroxide (Kishida Chemical Co., Ltd.) (G) Other low shrinkage agents: PS MS-200 (polystyrene, Sekisui Plastics Co., Ltd.)

[0128] Example 1 (Preparation of thermosetting resin composition) A thermosetting resin composition was prepared by adding 27 parts by mass of a mixture of (A) saturated polyester resin and (C) the ethylenically unsaturated monomer obtained in Synthesis Example 1 with styrene (16 parts by mass of saturated polyester resin, 11 parts by mass of styrene), (B) 85 parts by mass of a mixture of (B) unsaturated polyester resin and (C) the ethylenically unsaturated monomer obtained in Synthesis Example 6 with styrene (51 parts by mass of unsaturated polyester resin, 34 parts by mass of styrene), an additional 4 parts by mass of styrene as the (C) ethylenically unsaturated monomer, (D) 4 parts by mass of Perhexyl (trademark) I as a thermal polymerization initiator, (E) 36 parts by mass of chopped strand ECS-03B173 / P9 as glass fibers, (F) 390 parts by mass of Softon 1200 and 0.4 parts by mass of calcium hydroxide as inorganic fillers, and (G) 6 parts by mass of polystyrene as an additional low-shrinkage agent to a twin-arm kneader and kneading for 30 minutes at 30°C.

[0129] (Viscosity) The viscosity of the thermosetting resin composition immediately after kneading was evaluated using a flow tester. Specifically, a flow tester viscosity measuring instrument (measuring instrument: CFT-500D, manufactured in 2011, Shimadzu Corporation) was used to measure the flow tester viscosity (Pa·S) of the thermosetting resin composition using a φ1.5 mm × 10 mm die under conditions of a heating temperature of 70°C and a load of 7 MPa. The results are shown in Table 3.

[0130] (Initial molding shrinkage) In accordance with JIS K-6911 (2006) 5.7, a disk-shaped test specimen (φ90 mm × 11 mm) was obtained by compression molding using a compression molding machine (Technomarushi Co., Ltd.) under conditions of a molding temperature of 120°C, a molding pressure of 5 MPa, and a molding time of 3 minutes, and the molding shrinkage was calculated. The test specimen was prepared using a thermosetting resin composition immediately after kneading. The results are shown in Table 3.

[0131] (Molding shrinkage rate after change over time) In accordance with JIS K-6911 (2006) 5.7, a disk-shaped test specimen (φ90 mm × 11 mm) was obtained by compression molding using a compression molding machine (Technomarushi Co., Ltd.) under conditions of a molding temperature of 120°C, a molding pressure of 5 MPa, and a molding time of 3 minutes, and the molding shrinkage rate was calculated. The test specimen was prepared using a thermosetting resin composition that had been kneaded and then stored in a 20°C environment for 30 days. The results are shown in Table 3.

[0132] (Preparation of molded stator) A stator was placed in a mold, and a thermosetting resin composition was injected and molded at a molding temperature of 130°C, a molding pressure of 5 MPa, and a molding time of 5 minutes to obtain a molded stator. The filling property during molding and the appearance of the molded stator in terms of cracks were evaluated according to the following criteria. The results are shown in Table 3.

[0133] <<Initial Filling Property During Molding of Molded Stator>> The appearance of a molded stator produced using the thermosetting resin composition immediately after kneading was visually observed, and a state in which the cured product of the thermosetting resin composition was completely filled along the shape of the mold without any defects was rated as good, and a state in which there were some defects was rated as poor.

[0134] <<Filling property during molding of molded stator after change over time>> The appearance of a molded stator produced using a thermosetting resin composition that had been kneaded and then stored in an environment of 20°C for 30 days was visually observed, and a state in which the cured product of the thermosetting resin composition was completely filled along the mold shape without any defects was rated as good, and a state in which there were partial defects was rated as poor.

[0135] <<Initial Appearance of Molded Stator from the Viewpoint of Cracks>> The appearance of a molded stator produced using a thermosetting resin composition immediately after kneading was visually observed, and those with no cracks were rated as good, and those with cracks were rated as poor.

[0136] <<Appearance of Molded Stator from the Viewpoint of Cracks After Change Over Time>> The appearance of a molded stator produced using a thermosetting resin composition that had been kneaded and then stored in an environment of 20°C for 30 days was visually observed, and a molded stator with no cracks was rated as good, and a molded stator with cracks was rated as poor.

[0137] (Heat Cycle Test) A molded stator was produced using a thermosetting resin composition that had been kneaded and then stored in a 20°C environment for 30 days. A heat cycle test was conducted in air using a heat cycle tester (testing machine: TSA-71L-A, manufactured in 2010, Espec Corporation), with one cycle consisting of 20 minutes at -40°C and 20 minutes at 140°C. The test was conducted for 250 cycles, and the appearance of the molded stator was visually observed every 50 cycles to check for the occurrence of cracks. The maximum number of cycles without cracks occurring is shown in Table 3.

[0138]

[0139] Examples 2 to 9, Comparative Examples 1 to 3 Thermosetting resin compositions were prepared in the same manner as in Example 1, except that the compositions of raw materials were changed as shown in Table 3. Then, various evaluations were carried out in the same manner as in Example 1. The results are shown in Table 3. Note that a heat cycle test was not carried out for Comparative Examples 1 to 3.

[0140] REFERENCE SIGNS LIST 10 Motor 11 Stator 12 Stator core 13 Coil 14 Molding material 15 Rotor 16 Magnet 17 Rotating shaft 18 Rotating body 19 Bearing

Claims

1. A molded stator comprising: a stator having a stator core and a coil wound around the stator core; and a molding material covering the stator, wherein the molding material is a cured product of a thermosetting resin composition containing (A) a saturated polyester resin, (B) an unsaturated polyester resin, (C) an ethylenically unsaturated monomer, (D) a thermal polymerization initiator, (E) glass fiber, and (F) an inorganic filler, wherein the (B) unsaturated polyester resin contains at least an (B-1) unsaturated polyester resin, and the (B-1) unsaturated polyester resin is a polycondensate of a mixture containing a diol and an unsaturated polybasic acid, and the (B-1) unsaturated polyester resin contains a structure derived from propylene glycol and a structure derived from neopentyl glycol.

2. A molded stator according to claim 1, wherein the content ratio (molar ratio) of the structure derived from propylene glycol to the structure derived from neopentyl glycol in the (B-1) unsaturated polyester resin is 10:90 to 90:

10.

3. The molded stator according to claim 1, wherein the unsaturated polyester resin (B-1) further contains a structure derived from hydrogenated bisphenol A.

4. The molded stator according to claim 1, wherein the unsaturated polyester resin (B) further contains an unsaturated polyester resin (B-2), the unsaturated polyester resin (B-2) is a polycondensate of a mixture containing a diol and an unsaturated polybasic acid, and the unsaturated polyester resin (B-2) contains a structure derived from propylene glycol and does not contain a structure derived from neopentyl glycol.

5. The molded stator according to claim 1, wherein the unsaturated polyester resin (B-1) contains a structure derived from a saturated polybasic acid.

6. The molded stator according to claim 4, wherein the unsaturated polyester resin (B-2) contains a structure derived from a saturated polybasic acid.

7. The molded stator according to claim 1, wherein the weight average molecular weight of the unsaturated polyester resin (B-1) is 10,000 to 50,000.

8. The molded stator according to claim 1, wherein the saturated polyester resin (A) is a polycondensate of a mixture containing a diol and a saturated polybasic acid, and the saturated polybasic acid contains an aromatic saturated polybasic acid or its acid anhydride, and an aliphatic saturated polybasic acid.

9. The molded stator according to claim 8, wherein the content ratio (molar ratio) of the structure derived from the aromatic saturated polybasic acid or its acid anhydride to the structure derived from the aliphatic saturated polybasic acid in the saturated polyester resin (A) is 20:80 to 80:20, the saturated polyester resin (A) comprises a block (X) which is a polycondensate of a diol and an aromatic saturated polybasic acid or its acid anhydride, and a block (Y) which is a polycondensate of a diol and an aliphatic saturated polybasic acid, and the weight average molecular weight of the block (X) is 3,000 to 5,000.

10. The molded stator according to claim 9, wherein the aromatic saturated polybasic acid constituting the block (X) is at least one selected from the group consisting of isophthalic acid and terephthalic acid.

11. The molded stator according to claim 9, wherein the aliphatic saturated polybasic acid constituting the block (Y) is at least one selected from the group consisting of succinic acid, adipic acid, and sebacic acid.

12. The molded stator according to claim 1, wherein the weight average molecular weight of the saturated polyester resin (A) is 9,500 to 13,500.

13. The molded stator according to claim 1, wherein the thermosetting resin composition contains: 100 parts by mass of the total amount of the (B) unsaturated polyester resin and the (C) ethylenically unsaturated monomer; 5 to 30 parts by mass of the (A) saturated polyester resin; 20 to 80 parts by mass of the (B) unsaturated polyester resin; 80 to 20 parts by mass of the (C) ethylenically unsaturated monomer; 0.5 to 20 parts by mass of the (D) thermal polymerization initiator; 5 to 150 parts by mass of the (E) glass fiber; and 50 to 1,000 parts by mass of the (F) inorganic filler.

14. A motor comprising: a molded stator according to any one of claims 1 to 13; a rotating shaft extending in an axial direction; a rotating body including a magnet component extending in the axial direction and fixed to the rotating shaft; a rotor located inside the stator; and a bearing supporting the rotor for free rotation.

15. A thermosetting resin composition comprising: (A) a saturated polyester resin; (B) an unsaturated polyester resin; (C) an ethylenically unsaturated monomer; (D) a thermal polymerization initiator; (E) glass fiber; and (F) an inorganic filler; the (B) unsaturated polyester resin contains at least (B-1) an unsaturated polyester resin; the (B-1) unsaturated polyester resin is a polycondensate of a mixture containing a diol and an unsaturated polybasic acid; and the (B-1) unsaturated polyester resin contains a structure derived from propylene glycol and a structure derived from neopentyl glycol.

16. The thermosetting resin composition according to claim 15, wherein the unsaturated polyester resin (B-1) further contains a structure derived from hydrogenated bisphenol A.

17. The thermosetting resin composition according to claim 15, wherein the saturated polyester resin (A) is a polycondensate of a mixture containing a diol and a saturated polybasic acid, the saturated polybasic acid contains an aromatic saturated polybasic acid or an acid anhydride thereof, and an aliphatic saturated polybasic acid, the content ratio (molar ratio) of the structure derived from the aromatic saturated polybasic acid or an acid anhydride thereof to the structure derived from the aliphatic saturated polybasic acid in the saturated polyester resin (A) is 20:80 to 80:20, and the saturated polyester resin (A) contains a block (X) which is a polycondensate of a diol and an aromatic saturated polybasic acid or an acid anhydride thereof, and a block (Y) which is a polycondensate of a diol and an aliphatic saturated polybasic acid, and the weight average molecular weight of the block (X) is 3,000 to 5,000.

18. The thermosetting resin composition according to claim 15, comprising: 5 to 30 parts by mass of said (A) saturated polyester resin; 20 to 80 parts by mass of said (B) unsaturated polyester resin; 80 to 20 parts by mass of said (C) ethylenically unsaturated monomer; 0.5 to 20 parts by mass of said (D) thermal polymerization initiator; 5 to 150 parts by mass of said (E) glass fiber; and 50 to 1,000 parts by mass of said (F) inorganic filler, assuming that the total amount of said (B) unsaturated polyester resin and said (C) ethylenically unsaturated monomer is 100 parts by mass.

19. A molding material which is a cured product of the thermosetting resin composition according to any one of claims 15 to 18.

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