Epoxy resin composition

Abstract

To provide an epoxy resin composition which gives a cured product having excellent heat resistance (high glass transition temperature) and high peel adhesive strength.SOLUTION: The epoxy resin composition contains (A) an epoxy resin having two epoxy groups in one molecule, (B) an epoxy resin having more than two epoxy groups in one molecule, (C) core-shell type rubber particles whose core part is a diene rubber, (D) thickening particles, (E) a latent curing agent, and (F) an inorganic filler in a specific ratio.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an epoxy resin composition, and more particularly to an epoxy resin composition used for fixing insulating coils used in motors and generators. [Background technology]

[0002] The enamel-coated insulated coils of motors and generators built into vehicles and industrial machines, including automobiles and trains, are at risk of short-circuiting between adjacent coils due to deterioration of the insulation of the coating, or of coil breakage due to friction caused by vibration, etc., resulting in motor stoppage, etc., caused by the influence of the usage environment such as humidity and dust, or by vibration from the high-speed rotational movement of the rotor of the motor or generator, or vibration or impact from the automobile or other device in which they are installed. In order to prevent such deterioration of insulation and to protect the insulated coils from damage and breakage, a liquid epoxy resin is impregnated and hardened between the insulated coils to fix the insulated coils together and to bond them to the iron core.

[0003] In recent years, the properties required for this epoxy resin composition for impregnation and adhesion have become increasingly important, particularly in automotive applications. With the trend towards hybridization of drive mechanisms in automobiles, Automotive motors, especially drive motors and generators, are becoming smaller and more powerful. As a result, the amount of heat generated increases due to improved coil winding density and increased rotation speed, and the heat resistance of the epoxy resins that have been used conventionally for impregnation and fixing is no longer sufficient.

[0004] In order to solve this problem, for example, Patent Document 1 proposes an epoxy resin composition containing an epoxy resin that is liquid at room temperature, methyl hydride and a latent curing accelerator, but this does not sufficiently meet the above-mentioned demand for improved heat resistance.

[0005] Another method for improving the heat resistance of epoxy resin cured products is known to be a method of improving crosslink density using a multifunctional epoxy resin. For example, Patent Document 2 proposes a one-liquid epoxy composition that contains a mixed epoxy resin obtained by dissolving an epoxy resin having more than two epoxy groups in one molecule in a liquid epoxy resin, a liquid curing agent, and a curing accelerator. The composition has a high glass transition temperature due to the improvement in crosslink density, and while the heat resistance is improved, the peel adhesion strength may be insufficient. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2008 / 032704 Brochure [Patent Document 2] JP 2013-181124 A Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention provides an epoxy resin composition which gives a cured product having excellent heat resistance (high glass transition temperature) and high peel adhesion strength. [Means for solving the problem]

[0008] The present inventors have conducted various studies to solve the above problems, and have found that the above problems can be solved by an epoxy resin composition containing (A) an epoxy resin having two epoxy groups in one molecule, (B) an epoxy resin having more than two epoxy groups in one molecule, (C) core-shell type rubber particles whose core is a diene rubber, (D) thickening particles, (E) a latent curing agent, and (F) an inorganic filler in specific ratios. Specifically, the present invention includes the following inventions.

[0009] [1] Below (A)~(F): (A) Epoxy resin having two epoxy groups in one molecule (B) Epoxy resin having more than two epoxy groups in one molecule (C) Core-shell type rubber particles in which the core is a diene rubber (D) Viscosity enhancing particles (E) Latent hardener (F) Inorganic filler the content of (B) is 35 to 65 parts by weight per 100 parts by weight of the total content of (A) and (B), the content of (C) is 6 to 35 parts by weight per 100 parts by weight of the total content of (A) and (B), the content of (D) is 5 to 13 parts by weight per 100 parts by weight of the total content of (A) and (B), the content of (F) is 0.5 part by weight or more per 100 parts by weight of the total content of (A) and (B), and the total content of (C) and (F) is 27 to 45 parts by weight per 100 parts by weight of the total content of (A) and (B).

[0010] [2] (B) The epoxy resin composition according to [1], which contains at least an aminophenol-type epoxy resin as the epoxy resin having more than two epoxy groups in one molecule.

[0011] [3] The epoxy resin composition according to [1] or [2], comprising at least dicyandiamide as a latent curing agent (E).

[0012] [4] (F) The epoxy resin composition according to any one of [1] to [3], containing at least silica and calcium carbonate as an inorganic filler.

[0013] [5] The epoxy resin composition according to any one of [1] to [4], comprising, as the (D) thickening particles, at least an acrylic acid ester polymer and / or a methacrylic acid ester polymer not having a core-shell structure.

[0014] [6] A coil impregnated and fixed with the epoxy resin composition according to any one of [1] to [5].

[0015] [7] A motor and / or generator having the coil according to [6].

[0016] [8] A structural adhesive using the epoxy resin composition according to any one of [1] to [5]. Effect of the Invention

[0017] The epoxy resin composition of the present invention is characterized by excellent heat resistance (high glass transition temperature) and high peel adhesion strength, and therefore can be suitably used for bonding insulating coils used in motors, generators, etc., to each other and to their iron cores, and as a structural adhesive.

[0018] Generally, the epoxy resin is generally prepared by lowering the crosslink density by adding a rubber-based modifier, thereby improving the plastic deformation ability of the epoxy resin and increasing the toughness, and thus increasing the peel adhesion strength. However, since lowering the crosslink density also leads to lowering the heat resistance, it has been considered difficult to achieve both high peel adhesion strength and high heat resistance in epoxy resins to which a rubber-based modifier has been added. However, in the present invention, by making the epoxy resin composition having the above-mentioned structure, it is possible to achieve both high peel adhesion strength and high heat resistance. BEST MODE FOR CARRYING OUT THEINVENTION

[0019] <Epoxy resin composition> The epoxy resin composition of the present invention contains (A) an epoxy resin having two epoxy groups in one molecule, (B) an epoxy resin having more than two epoxy groups in one molecule, (C) core-shell type rubber particles whose core portion is a diene-based rubber, (D) thickening particles, (E) a latent curing agent, and (F) an inorganic filler.

[0020] <(A) Epoxy resin having two epoxy groups in one molecule> Examples of the epoxy resin having two epoxy groups in one molecule used in the present invention include bisphenol epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AD ​​type epoxy resins, alkylene oxide modified bisphenol A type epoxy resins, and alkylene oxide modified bisphenol F type epoxy resins, naphthalene type bifunctional epoxy resins, biphenyl type epoxy resins, alicyclic epoxy resins (cyclohexene oxide or cyclopentene oxide containing compounds obtained by epoxidizing cyclohexene or cyclopentene ring containing compounds with an oxidizing agent, or compounds having at least one epoxy group in one molecule, such as ... Examples of such polyglycidyl ethers include polyglycidyl ethers obtained by reacting epihalohydrin with a dihydric phenol such as catechol or resorcin, or a dihydric alcohol such as 1,4-butanediol, 1,6-hexanediol, or polyethylene glycol, and epihalohydrin; glycidyl ether esters obtained by reacting epihalohydrin with a hydroxycarboxylic acid such as p-oxybenzoic acid; and polyglycidyl esters obtained by reacting epihalohydrin with a polycarboxylic acid such as phthalic acid, terephthalic acid, hexahydrophthalic acid, or a long-chain dibasic acid.

[0021] At least one of the above-mentioned epoxy resins having two epoxy groups in one molecule is preferably liquid at room temperature (25°C), since this improves flow into the narrow gaps between the insulated coils.

[0022] Among the above-mentioned epoxy resins having two epoxy groups in one molecule, bisphenol A type epoxy resins and bisphenol F type epoxy resins are preferably used. Bisphenol A type epoxy resins and bisphenol F type epoxy resins are preferred because they are relatively inexpensive.

[0023] The epoxy resin having two epoxy groups in one molecule may be a commercially available product. Examples of commercially available bisphenol A type epoxy resins include DER331, DER383 (all manufactured by OLIN), jER828, jER828EL (all manufactured by Mitsubishi Chemical), Epiclon 850, Epiclon 850-S (all manufactured by DIC), etc. Examples of commercially available bisphenol F type epoxy resins include jER807 (manufactured by Mitsubishi Chemical), Epiclon 830, Epiclon 830-S (all manufactured by DIC), etc.

[0024] The epoxy resin having two epoxy groups in one molecule may be used alone or in combination of two or more kinds.

[0025] <(B) Epoxy resin having more than two epoxy groups in one molecule> Examples of the epoxy resin having more than two epoxy groups in one molecule used in the present invention include novolac type epoxy resins such as naphthalene type tetrafunctional epoxy resins, epoxy resins having a dicyclopentadiene skeleton, epoxy resins having a triazine skeleton, phenol novolac type epoxy resins, cresol novolac type epoxy resins, and bisphenol A type novolac type epoxy resins; glycidyl amine type epoxy compounds such as biphenyl aralkyl type epoxy resins, tetrakisphenol ethane type epoxy resins, trishydroxyphenylmethane type epoxy resins, aromatic amine type epoxy resins, aliphatic amine type epoxy resins, alicyclic amine type epoxy resins, diphenyl diaminomethane type epoxy resins, and aminophenol type epoxy resins; aliphatic epoxy resins such as trimethylolpropane polyglycidyl ether and pentaerythritol polyglycidyl ether; and epoxy group-containing polymers such as epoxy modified butadiene and epoxy modified acrylic-styrene type polymers.

[0026] At least one of the above-mentioned epoxy resins having two or more epoxy groups in one molecule is preferably liquid at room temperature (25°C) since this improves flow into the narrow gaps between the insulated coils.

[0027] Among the above-mentioned epoxy resins having more than two epoxy groups in one molecule, preferably, aromatic amine type epoxy resins (e.g., N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenyl ether, tetraglycidyl meta-xylylene diamine, etc.) and aminophenol type epoxy resins (e.g., N,N,O-triglycidyl-p-aminophenol, N,N,O-triglycidyl-p-amino-m-cresol, etc.), more preferably, aminophenol type epoxy resins are used.

[0028] The epoxy resin having more than two epoxy groups in one molecule may be a commercially available product. Examples of commercially available aromatic amine type epoxy resins include jER604 (N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenyl ether, manufactured by Mitsubishi Chemical Corporation), Sumiepoxy ELM-434, ELM-434VL, ELM-434L (N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenyl ether, manufactured by Sumitomo Chemical Co., Ltd.), TETRAD-X (tetraglycidyl metaxylenediamine, manufactured by Mitsubishi Gas Chemical Co., Ltd.), and the like. Commercially available aminophenol type epoxy resins include, for example, jER630 (N,N,O-triglycidyl-p-aminophenol, manufactured by Mitsubishi Chemical Corporation), Sumiepoxy ELM-100H, and ELM-100 (N,N,O-triglycidyl-p-amino-m-cresol, manufactured by Sumitomo Chemical Co., Ltd.).

[0029] The epoxy resin having two or more epoxy groups in one molecule may be used alone or in combination of two or more kinds.

[0030] <Proportion of (B) epoxy resin having more than two epoxy groups in one molecule contained in the epoxy resin composition> The amount of (B) contained in the epoxy resin composition of the present invention is usually 35 to 65 parts by weight, preferably 40 to 60 parts by weight, and more preferably 50 to 60 parts by weight, based on 100 parts by weight of the total amount of (A) and (B). If the amount is within the range of 35 to 65 parts by weight, it is possible to improve the peel adhesion strength while maintaining high heat resistance (glass transition temperature).

[0031] <(C) Core-shell type rubber particles in which the core is a diene rubber> The core-shell type rubber particles in which the core part is a diene rubber in the present invention are polymer particles composed of a core part mainly composed of a diene rubber-like polymer and a shell layer mainly composed of a polymer component that covers the core part. Examples of the diene rubber-like polymer in the core part include polymers of conjugated diene monomers such as butadiene, isoprene, and chloroprene. Examples of the polymer that covers the core part include (co)polymers of (meth)acrylate monomers, aromatic vinyl monomers, and vinyl cyanide monomers, and silicone resins.

[0032] The core-shell type rubber particles having a diene rubber core may be commercially available, such as KaneAce manufactured by Kaneka Corporation (e.g., B-series such as B-11A and B-521, M-series such as M-701, M-711, M-732, etc.), and Metablen manufactured by Mitsubishi Chemical Corporation (e.g., C-type such as C-223A, E-type such as E-870A, E-875A, etc.).

[0033] These core-shell type rubber particles whose core part is a diene rubber can be used in the form of fine powder. In this case, the fine powder is dispersed as uniformly as possible in the above-mentioned (A) epoxy resin having 2 or less epoxy groups in one molecule and / or (B) epoxy resin having more than 2 epoxy groups in one molecule, and mixed so as not to generate aggregates or lumps. The core-shell type rubber particles whose core part is a diene rubber may be prepared as a dispersion (hereinafter sometimes referred to as a rubber particle dispersion) in which they are dispersed in an epoxy resin in advance, and then mixed with the above-mentioned (A) epoxy resin having 2 or less epoxy groups in one molecule and / or (B) epoxy resin having more than 2 epoxy groups in one molecule for use. In the rubber particle dispersion, the epoxy resin in which the core-shell type rubber particles whose core part is a diene rubber are dispersed may be any epoxy resin that is liquid at 25°C, and examples thereof include bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, aromatic amine type epoxy resin, and aminophenol type epoxy resin. The ratio of the core-shell type rubber particles whose core part is a diene rubber in the rubber particle dispersion is, for example, 25% by weight to 40% by weight, preferably 30% by weight to 40% by weight. If the rubber particle dispersion is one in which the core-shell type rubber particles whose core part is a diene rubber are dispersed in the state of primary particles, the core-shell type rubber particles whose core part is a diene rubber can be blended and dispersed in the epoxy composition of the present invention at a higher concentration, and the physical properties of the core-shell type rubber particles are more effectively expressed, which is preferable.

[0034] Examples of commercially available rubber particle dispersions include KaneAce MX series manufactured by Kaneka Corporation (e.g., MX-153, MX-257, MX-154, MX-136, MX-267, MX-217, MX-416, MX-451). Among these commercially available rubber particle dispersions, KaneAce MX-267 (37% by weight bisphenol F type epoxy dispersion of butadiene rubber), KaneAce MX-153 (33% by weight bisphenol A type epoxy dispersion of butadiene rubber), KaneAce MX-257 (37% by weight bisphenol A type epoxy dispersion of butadiene rubber), and KaneAce MX-154 (40% by weight bisphenol A type epoxy dispersion of butadiene rubber) are preferred, in which core-shell type rubber particles are dispersed at a high concentration.

[0035] These core-shell type rubber particles and rubber particle dispersions in which the core portion is a diene rubber may be used alone or in combination of two or more kinds.

[0036] <Proportion of (C) core-shell type rubber particles in which the core part is a diene rubber contained in the epoxy resin composition> The amount of (C) contained in the epoxy resin composition of the present invention is usually 6 to 35 parts by weight, and preferably 11 to 30 parts by weight, per 100 parts by weight of the total content of (A) and (B).

[0037] <(D) Thickening particles> In the present invention, the thickening particles are thermoplastic resins or those mainly composed of thermoplastic resins, which can be uniformly dispersed in (A) epoxy resins having two or less epoxy groups in one molecule and / or (B) epoxy resins having more than two epoxy groups in one molecule at room temperature (25°C), and when this dispersion is heated, it swells in a specific temperature range, and when heated further, the swelling progresses and the viscosity increases rapidly, dissolving in the epoxy resin dispersion medium or forming a layer, and forming a domain of a sea-island structure by phase separation during curing. Note that particles having a core-shell structure are not included in the thickening particles in the present invention because they are difficult to swell in the epoxy resin composition and have a low effect of increasing the viscosity. In addition, it is preferable that the thickening particles thicken and swell at a temperature lower than the curing temperature of the epoxy resin composition of the present invention.

[0038] The thickening particles used in the present invention are preferably thermoplastic resins or those mainly made of thermoplastic resins.The thermoplastic resins are not particularly limited, but are preferably solid at room temperature, and more preferably usable as powder or fine particles.Specifically, for example, they preferably contain a resin having at least one monomer unit selected from the group consisting of acrylic acid ester compounds, methacrylic acid ester compounds, and vinyl compounds, and more preferably contain a resin having methacrylic acid ester compounds as monomer units.

[0039] The acrylic acid ester compound refers to a compound having an acrylic acid ester structure and a derivative thereof, and examples thereof include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, t-butyl acrylate, n-hexyl acrylate, and cyclohexyl acrylate.

[0040] The methacrylic acid ester compound refers to a compound having a methacrylic acid ester structure and a derivative thereof, and examples thereof include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, n-hexyl methacrylate, and cyclohexyl methacrylate.

[0041] The vinyl compound refers to a compound having a polymerizable vinyl structure, and examples thereof include styrene, α-methylstyrene, divinylbenzene, and compounds in which the aromatic rings of these compounds are substituted with various functional groups such as alkyl groups and halogen atoms.

[0042] The thickening particles may be composed of a single thermoplastic resin, or may be composed of two or more different thermoplastic resins.

[0043] The thickening particles may be commercially available products, such as Zefiac F325 and Zefiac F320 manufactured by Aica Kogyo Co., Ltd., which are made of polymethyl methacrylate and do not have a core-shell structure.

[0044] These thickening particles may be used alone or in combination of two or more kinds.

[0045] The thickening particles may be dispersed in the epoxy resin beforehand. By using the thickening particles dispersed in the epoxy resin beforehand, the stirring and mixing time required to achieve uniform dispersion can be shortened. The epoxy resin used for dispersion may be liquid at 25°C, and examples thereof include bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, aromatic amine type epoxy resin, and aminophenol type epoxy resin.

[0046] <Proportion of (D) thickening particles contained in epoxy resin composition> The amount of (D) contained in the epoxy resin composition of the present invention is 5 to 13 parts by weight, preferably 7 to 11 parts by weight, per 100 parts by weight of the total amount of (A) and (B). If the amount is within the range of 5 to 13 parts by weight, it is possible to improve the peel adhesion strength while maintaining high heat resistance (high glass transition temperature).

[0047] <(E) Latent hardener> Examples of the latent curing agent used in the present invention include dihydrazide compounds, dicyandiamide, imidazole compounds, imidazole adduct compounds, amine adduct compounds, modified aliphatic polyamine compounds, etc. Examples of the dihydrazide compounds include adipic acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide, maleic acid dihydrazide, dodecanedioic acid dihydrazide, Amicure VDH and Amicure UDH manufactured by Ajinomoto Technofine Co., Ltd. Examples of the imidazole compounds include 2-phenylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, etc. Examples of imidazole adduct compounds include Amicure PN-23 and Amicure PN-R manufactured by Ajinomoto Technofine Co., Ltd., and examples of amine adduct compounds include Amicure MY-24 and Amicure MY-R manufactured by Ajinomoto Technofine Co., Ltd., and the adduct compounds shown in JP-A-57-100127 or JP-A-2017-178981. Examples of modified aliphatic polyamine compounds include Fujicure FXE-1000 and FXR-1121 manufactured by T&K TOKA. The latent curing agent may be used alone or in combination of two or more kinds.

[0048] The amount of (E) contained in the epoxy resin composition of the present invention is not particularly limited, but is, for example, 2 to 20 parts by weight, and preferably 8 to 14 parts by weight, per 100 parts by weight of the total content of (A) and (B).

[0049] Among the above-mentioned latent curing agents, the epoxy resin composition of the present invention preferably contains at least dicyandiamide from the viewpoint of further improving adhesion to metal. Dicyandiamide can be used alone, but when used alone, it requires heating at 180°C or higher for curing, so when it is desired to cure at a lower temperature, it is preferable to use it in combination with a latent curing agent other than dicyandiamide. As the latent curing agent to be used in combination with dicyandiamide, imidazole adduct compounds and amine adduct compounds are preferable.

[0050] When dicyandiamide and a latent curing agent other than dicyandiamide are used in combination, the content of dicyandiamide is, for example, 1 to 10 parts by weight and the content of the latent curing agent other than dicyandiamide is 0.5 to 30 parts by weight, and preferably the content of dicyandiamide is 1 to 5 parts by weight and the content of the latent curing agent other than dicyandiamide is 3 to 20 parts by weight, relative to 100 parts by weight of the total amount of the epoxy resins (A) and (B).

[0051] In addition, dicyandiamide and / or a latent curing agent other than dicyandiamide may be used after being dispersed in the epoxy resin in advance. By using the epoxy resin after being dispersed in advance, the stirring and mixing time until uniform dispersion can be shortened. The epoxy resin used for dispersion may be liquid at 25°C, and examples thereof include bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, aromatic amine type epoxy resin, and aminophenol type epoxy resin.

[0052] <(F) Inorganic filler> Examples of the inorganic filler used in the present invention include calcium carbonate, barium sulfate, fused silica, crystalline silica, glass filler, aluminum hydroxide, magnesium hydroxide, alumina, etc. The inorganic filler may be used alone or in combination of two or more kinds.

[0053] <Proportion of (F) inorganic filler contained in epoxy resin composition> The amount of (F) contained in the epoxy resin composition of the present invention is 0.5 parts by weight or more, preferably 30 parts by weight or less, based on 100 parts by weight of the total content of (A) and (B). The total content of (C) and (F) is 27 to 45 parts by weight, preferably 29 to 37 parts by weight, based on 100 parts by weight of the total content of (A) and (B). By making the content of (C) 6 to 35 parts by weight, the content of (F) 0.5 parts by weight or more, and the total content of (C) and (F) within the range of 27 to 45 parts by weight, it is possible to improve the peel adhesion strength while maintaining high heat resistance (high glass transition temperature). In addition, the viscosity at room temperature (25°C) is not too high, resulting in an epoxy resin composition with excellent handleability.

[0054] <Other ingredients> The epoxy resin composition of the present invention may contain, as necessary, organic fillers other than (C) and (D), coupling agents, colorants, non-reactive diluents, etc. Examples of organic fillers other than (C) and (D) include core-shell type rubber particles whose core is an acrylic rubber type, and core-shell type rubber particles whose core is a silicone rubber type. Examples of coupling agents include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, etc. Examples of colorants include carbon black, titanium oxide, etc. Examples of non-reactive diluents include organic solvents such as xylene and cellosolve, and plasticizers such as dimethyl phthalate, dibutyl phthalate, diisononyl phthalate, and tricresyl phosphate.

[0055] In addition to the above-mentioned other components, the epoxy resin composition of the present invention may contain, if necessary, a leveling agent, an antifoaming agent, a wetting and dispersing agent, a flame retardant, a stabilizer, etc.

[0056] <Method for preparing epoxy resin composition> The method for preparing the epoxy resin composition of the present invention employs a general stirring and mixing device and mixing conditions similar to the method for preparing a normal epoxy resin composition. Devices that can be used include a mixing roll, a dissolver, a planetary mixer, a kneader, an extruder, and the like. During mixing, the epoxy resin, etc. may be heated to dissolve and / or reduce the viscosity and improve the stirring and mixing efficiency. In addition, cooling may be performed as necessary to remove heat generated by friction, reaction, and the like. The stirring and mixing time may be determined as necessary and is not particularly limited.

[0057] Next, the cured product of the present invention will be described. The cured product of the present invention can be obtained by curing the epoxy resin composition of the present invention by heating. Specifically, for example, the cured product can be obtained by heating the epoxy resin composition of the present invention at 80 to 200°C for 10 minutes to 10 hours.

[0058] The epoxy resin composition of the present invention has a viscosity that is not too high (for example, a viscosity of 500 Pa·s or less at room temperature (25° C.)) and is excellent in handleability. In addition, the cured product obtained by curing the epoxy resin composition of the present invention as described above has a glass transition temperature of 150° C. or higher and high peel adhesion strength, and is therefore particularly suitable for use in bonding insulating coils used in motors, generators, and the like and bonding them to their iron cores. In addition, since it has excellent heat resistance and high peel strength, it can also be used as a structural adhesive for use in automobile bodies, automobile parts, machine tools, aircraft parts, transformers, and other locations requiring welding. The glass transition temperature, peel adhesion strength, and viscosity in the present invention are values ​​measured under the conditions described in the Examples section below.

[0059] Furthermore, the epoxy resin composition of the present invention can be made into an epoxy resin composition that is liquid at 25°C, if necessary, by using at least one of (A) an epoxy resin having two or less epoxy groups in one molecule and (B) an epoxy resin having more than two epoxy groups in one molecule that is liquid at 25°C. EXAMPLES

[0060] EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these in any way.

[0061] (Examples 1 to 9, Comparative Examples 1 to 9) Each component was weighed according to Tables 1 and 2, and stirred and mixed using a stirring defoamer (ARE-300, manufactured by Thinky Corporation) to prepare epoxy resin compositions according to each of the Examples and Comparative Examples. Using the obtained epoxy resin compositions, various tests were carried out by the methods described below, and the obtained test results were evaluated according to the evaluation criteria described below. The evaluation results are shown in Tables 1 and 2. The blending amount of each component in Tables 1 and 2 is in parts by weight unless otherwise specified. The amount of core-shell type rubber particles contained in each product is shown in the column (C) in Table 1, and the columns (C) and (C') in Table 2, and the amount of epoxy resin, which is a dispersion medium, is shown in the column for (A) epoxy resin having two epoxy groups in one molecule.

[0062] (Measurement of glass transition temperature) The epoxy resin compositions obtained in each of the Examples and Comparative Examples were cured at 130°C for 60 minutes to obtain cured products. Test pieces measuring 3 mm x 5 mm x 5 mm were prepared from the obtained cured products, and measurements were performed on the prepared test pieces using a thermomechanical analyzer (TMA-7100 (Hitachi High-Tech Science Corporation) in a temperature range of 30-270°C at 5°C / min in compression mode. The glass transition temperature (Tg) was obtained from the TMA curve. The results of the adhesive strength evaluation according to the following criteria are shown in Tables 1 and 2. (Glass transition temperature evaluation criteria) Over 150℃: Yes Less than 150℃: ×

[0063] (Measurement of peel adhesion strength (T-type, steel-steel)) The epoxy resin composition obtained in each Example and Comparative Example was applied between two steel plates (0.3 mm x 25 mm x 150 mm), laminated together, and cured at 130°C for 30 minutes to prepare test specimens. The steel-to-steel adhesive strength of the prepared test specimens was measured in accordance with the measuring method for T-peel adhesion strength in JIS K6854-3. The results of the adhesive strength judged according to the following criteria are shown in Tables 1 and 2. (Evaluation criteria for peel adhesion strength (T-type, steel-steel)) ·1.5[N / mm] or more:◎ Less than 1.5 [N / mm], 1.2 [N / mm] or more: ○ Less than 1.2 [N / mm]: ×

[0064] (Viscosity measurement) The epoxy resin compositions obtained in each of the Examples and Comparative Examples were measured at a temperature of 25°C and a rotation speed of 1 rpm using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., product name: TV-25 type H, applicable cone-plate type rotor: 3°×R14). The results are shown in Tables 1 and 2.

[0065] The components in Tables 1 and 2 are as follows: (A) Epoxy resin having two epoxy groups in one molecule DER331: Bisphenol A type epoxy resin (OLIN) jER807: Bisphenol F type liquid epoxy resin (manufactured by Mitsubishi Chemical Corporation) (B) Epoxy resin having more than two glycidyl groups in one molecule jER630: Aminophenol trifunctional epoxy resin (manufactured by Mitsubishi Chemical Corporation) ELM-100: Aminocresol trifunctional epoxy resin (Sumitomo Chemical Co., Ltd.) (C) Core-shell type rubber particles in which the core is a diene rubber Kane Ace MX-154: 40% by weight butadiene rubber-based core-shell type rubber particles-containing bisphenol A type epoxy resin dispersion (Kaneka Corporation) (C') Other core-shell type rubber particles Kane Ace MX-960: 25% by weight silicone rubber-based core-shell type rubber particles-containing bisphenol A type epoxy resin dispersion (Kaneka Corporation) (D) Viscosity enhancing particles Zefiac F320: Polymethacrylate organic fine particles (manufactured by Aica Kogyo Co., Ltd.) (E) Latent hardener Dicyandiamide Fujicure FXR-1121: Modified aliphatic polyamine compound (manufactured by T&K TOKA) (F) Inorganic filler Aerosil 200: Hydrophilic fused silica (manufactured by Nippon Aerosil Co., Ltd.) Miclone 200: Fatty acid-treated light calcium carbonate (manufactured by NewLyme)

[0066] [Table 1]

[0067] [Table 2]

Claims

1. The following (A) to (F): (A) Epoxy resin having two epoxy groups in one molecule (B) Epoxy resin having more than two epoxy groups in one molecule (C) Core-shell type rubber particles in which the core is a diene rubber (D) Thickening particles (E) Latent hardener (F) Inorganic filler the content of (B) is 35 to 65 parts by weight per 100 parts by weight of the total content of (A) and (B), the content of (C) is 6 to 35 parts by weight per 100 parts by weight of the total content of (A) and (B), the content of (D) is 5 to 13 parts by weight per 100 parts by weight of the total content of (A) and (B), the content of (F) is 0.5 parts by weight or more per 100 parts by weight of the total content of (A) and (B), and the total content of (C) and (F) is 27 to 45 parts by weight per 100 parts by weight of the total content of (A) and (B), (D) is a thermoplastic resin or a material mainly composed of a thermoplastic resin (excluding particles having a core-shell structure), and (F) contains at least silica and calcium carbonate.

2. 2. The epoxy resin composition according to claim 1, comprising at least an aminophenol-type epoxy resin as (B) the epoxy resin having more than two epoxy groups in one molecule.

3. 3. The epoxy resin composition according to claim 1 or 2, comprising at least dicyandiamide as the latent curing agent (E).

4. 4. The epoxy resin composition according to claim 1, comprising as the thickening particles (D) at least an acrylic acid ester polymer and / or a methacrylic acid ester polymer not having a core-shell structure.

5. A coil impregnated and fixed with the epoxy resin composition according to any one of claims 1 to 4.

6. A motor and / or generator comprising the coil according to claim 5.

7. A structural adhesive using the epoxy resin composition according to any one of claims 1 to 4.

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