Epoxy resin compositions for injection molding and electrical and electronic components

Abstract

The object of the present invention is to provide an epoxy resin composition for injection molding that provides excellent thermal shock resistance and excellent impregnation properties for coils, etc. An epoxy resin composition for injection molding comprises epoxy resin, acid anhydride, and inorganic filler. In the epoxy resin composition for injection molding, the epoxy resin is a bisphenol type epoxy resin represented by the following general formula (1), and in gel permeation chromatography determination, the content of n=0 particles is 60% to 75% of the area, the total content of n=2 particles and above is 5% to 25% of the area, and the average particle size (D50) of the inorganic filler is 0.2 μm to 50 μm, with the inorganic filler comprising 50 to 500 parts by mass relative to 100 parts by mass of epoxy resin.

Description

[Technical Field]

[0001] This invention relates to an epoxy resin composition for injection molding and electrical and electronic components. [Previous Technology]

[0002] Since the beginning of time, epoxy resin compositions have been cured to obtain excellent mechanical, chemical and electrical properties. Therefore, epoxy resin compositions are widely used as adhesives, coatings and injection molding materials for the insulation and sealing of electrical parts such as coils and capacitors or electronic parts such as semiconductor components.

[0003] When epoxy resin compositions are used for injection molding applications such as electrical coils, epoxy resin compositions with excellent impregnation (injectionability), insulation and mechanical strength are selected. In recent years, the requirements for cost reduction, high functionality and improved workability have been increasing.

[0004] From the perspective of high functionality and high reliability, it is necessary to reduce the coefficient of thermal expansion and increase mechanical strength. This is achieved by incorporating inorganic fillers such as silicon dioxide (Patent Document 1). However, when inorganic fillers are incorporated, they settle during curing, which sometimes deteriorates the uniformity of the epoxy resin composition and reduces the reliability of the cured product, especially its resistance to thermal shock.

[0005] An effective method for suppressing the sedimentation of inorganic fillers in epoxy resin compositions is to impart thixotropy using a sedimentation prevention agent (Patent Document 2). However, when injection molding coils, etc., the increased thixotropy leads to a decrease in the impregnation of the coils, etc. Therefore, the reliability of the cured product, especially its thermal shock resistance, decreases. [Prior Art Documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2003-155394 [Patent Document 2] Japanese Patent Application Publication No. 2018-12745 [Summary of the Invention]

[0007] The purpose of this invention is to provide an epoxy resin composition for injection molding that can produce a hardened material with excellent thermal shock resistance and excellent impregnation properties for electrical and electronic components such as coils.

[0008] The inventors conducted intensive research to solve the aforementioned problem and discovered that by using an epoxy resin with a specific structure and molecular weight distribution, limiting the average particle size (D50) of the inorganic filler to a specific range, and setting the mixing ratio of epoxy resin and inorganic filler to a specific range, the inorganic filler exhibits less sedimentation, excellent impregnation properties for coils, etc., and a hardened material with excellent thermal shock resistance can be obtained, thus completing the present invention.

[0009] That is, an epoxy resin composition for injection molding, comprising epoxy resin, acid anhydride, and inorganic filler, wherein the epoxy resin is a bisphenol type epoxy resin represented by the following general formula (1), and in gel permeation chromatography (GPC) determination, the content of n=0 particles is 60% to 75% area, the total content of n=2 or more particles is 5% to 25% area, the average particle size (D50) of the inorganic filler is 0.2 μm to 50 μm, and the inorganic filler is 50 to 500 parts by mass relative to 100 parts by mass of epoxy resin.

[0010] [Chemical 1] In the formula, R1 and R2 are independently hydrogen atoms or hydrocarbon groups with 1 to 6 carbon atoms, and n is the number of repetitions, with an average of 0.5 to 5.

[0011] The viscosity of the epoxy resin at 25°C is preferably 60,000 mPa·s to 100,000 mPa·s, and the epoxy equivalent of the epoxy resin is preferably 180 g / eq. to 250 g / eq.

[0012] The epoxy resin is preferably a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin.

[0013] The acid anhydride is preferably in liquid form, and its viscosity at 25°C is preferably 30 mPa·s to 500 mPa·s.

[0014] Furthermore, the present invention relates to an electrical and electronic component, characterized in that: it is injection molded from the epoxy resin composition for injection molding. Regarding the epoxy resin composition for injection molding provided by the present invention, it is possible to obtain an epoxy resin composition with minimal sedimentation of inorganic fillers during curing, excellent impregnation properties for electrical and electronic components such as coils, and excellent thermal shock resistance in the cured product.

Implementation Method

[0015] Hereinafter, embodiments of the present invention will be described in detail. First, the epoxy resin composition for injection molding of the present invention will be described. The epoxy resin used in the epoxy resin composition for injection molding of the present invention (sometimes referred to as "the resin composition of the present invention") needs to be a bisphenol type epoxy resin represented by the general formula (1).

[0016] In formula (1), R1 and R2 are each independently a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. The hydrocarbon group having 1 to 6 carbon atoms is an alkyl or phenyl group having 1 to 6 carbon atoms. The alkyl group having 1 to 6 carbon atoms can be any of the following: linear, branched, or cyclic. Examples include: methyl, ethyl, propyl, isopropyl, n-butyl, dibutyl, tributyl, n-pentyl, neopentyl, dipentyl, tripentyl, cyclopentyl, methylcyclopentyl, hexyl, cyclohexyl, etc., but is not limited to these. From the viewpoint of ease of acquisition and reactivity when preparing a cured product, R1 and R2 are preferably hydrogen atoms, methyl, or phenyl, and more preferably hydrogen atoms or methyl.

[0017] The content of the n=0 component of the epoxy resin is 60% to 75% of area, preferably 62% to 72% of area, and more preferably 65% ​​to 70% of area. Furthermore, the total content of n=2 or more components is 5% to 25% of area, preferably 8% to 20% of area, and more preferably 10% to 16% of area. Moreover, the content of the n=1 component is the remainder, and is therefore calculated based on the content of the n=0 component and the content of n=2 or more components. If the epoxy resin has the aforementioned molecular weight distribution, it can be used. The manufacturing method is not particularly specified, but a method of mixing low-molecular-weight bisphenol-type epoxy resin with medium-molecular-weight bisphenol-type epoxy resin is preferred as it facilitates management of the molecular weight distribution. For example, a low-molecular-weight bisphenol type epoxy resin with an n=0 content of 65% or more is selected, and a medium-molecular-weight bisphenol type epoxy resin with a total n=2 content of 70% or more is selected. These are mixed in the desired proportions, thereby adjusting to have a specific molecular weight distribution as the bisphenol type epoxy resin represented by the general formula (1) of the present invention. In this case, a low-molecular-weight bisphenol type epoxy resin with a content of 60% or more by mass, and more preferably 70% or more by mass, can be formulated. By making the n=0 content within the aforementioned range, the viscosity of the epoxy resin becomes lower, so a resin composition with excellent impregnation properties for electrical and electronic components such as coils can be obtained without the need for large-scale formulation of diluents or low-viscosity liquid epoxy resins to reduce viscosity. Furthermore, since inorganic fillers can be adequately incorporated, a cured product with excellent thermal shock resistance can be obtained. Furthermore, by ensuring that the total amount of n=2 or more is within the aforementioned range, a hardened material with excellent mechanical properties (bending strength retention or high elongation) can be obtained.

[0018] Examples of bisphenol-type epoxy resins represented by formula (1) include: bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD ​​type epoxy resin, bisphenol acetophenone type epoxy resin, bisphenol C type epoxy resin, tetramethylbisphenol A type epoxy resin, and tetramethylbisphenol F type epoxy resin. These epoxy resins can be used alone or in combination. By mixing low-molecular-weight bisphenol-type epoxy resins and medium-molecular-weight bisphenol-type epoxy resins, epoxy resins with the preferred molecular weight distribution can also be prepared. Preferably, bisphenol A type or F type liquid epoxy resin is selected as the low-molecular-weight bisphenol-type epoxy resin, and bisphenol F type or A type solid epoxy resin is selected as the medium-molecular-weight bisphenol-type epoxy resin, and these are mixed and used.

[0019] The viscosity of the epoxy resin at 25°C is not particularly limited, but is preferably 60,000 mPa·s to 100,000 mPa·s, and more preferably 65,000 mPa·s to 80,000 mPa·s. Within this range, it is easy to suppress the settling of inorganic fillers during the hardening of the epoxy resin composition for injection molding, and good impregnation properties for coils, etc., can be obtained without reducing workability due to decreased fluidity.

[0020] The epoxy equivalent of the epoxy resin is preferably 180 g / eq. to 250 g / eq., more preferably 185 g / eq. to 225 g / eq. Within this range, a cured product with excellent thermal shock resistance can be obtained.

[0021] There is no particular limitation on the amount of epoxy resin to be mixed. From the viewpoints of workability, curability, and impregnation of coils, etc., it is preferred to be 5% to 40% by mass, and more preferably 10% to 30% by mass in the epoxy resin composition for injection molding.

[0022] As an anhydride-based curing agent used in this invention, it can be used without particular limitation as long as it contains an anhydride group in its molecule. However, it is preferred to use an anhydride-based curing agent that is liquid at room temperature, and its viscosity at 25°C is preferably 30 mPa·s to 500 mPa·s, more preferably 40 mPa·s to 200 mPa·s. Examples of such liquid anhydride-based curing agents include: methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, dodecenylsuccinic anhydride, methylneodymethylenetetrahydrophthalic anhydride, and their derivatives. In addition, when the anhydride-based curing agent is solid at room temperature, it is preferred to use it in combination with the liquid anhydride-based curing agent or as a eutectic mixture. Examples of solid anhydride-based curing agents include tetrahydrophthalic anhydride, hexahydrophthalic anhydride, nadic anhydride, polyazelaic anhydride, anhydrides containing trimellitic acid derivatives, benzophenone tetracarboxylic dianhydride, or pyromellitic anhydride, and their derivatives. These anhydride-based curing agents can be used alone or in combination of two or more. Furthermore, the anhydride equivalent of the anhydride-based curing agent is preferably 150 g / eq. to 400 g / eq., more preferably 170 g / eq. to 300 g / eq.

[0023] The amount of hardener is not particularly limited, but from the viewpoints of workability, curing properties, and impregnation of coils, etc., it is preferably 5% to 40% by mass, more preferably 10% to 30% by mass, in the epoxy resin composition for injection molding. Furthermore, the mixing ratio of epoxy resin to hardener is preferably 1 / 0.7 to 1.2 (total epoxy resin / total hardener) by equivalent ratio, more preferably 1 / 0.8 to 1.1. By setting it within the above range, excellent mechanical and electrical properties can be obtained when the epoxy resin composition for injection molding is cured.

[0024] The inorganic filler material used in this invention is not particularly limited. Examples include: silicon dioxide, alumina, calcium carbonate, aluminum hydroxide, talc, mica, etc. These can be used alone or in combination of two or more. Commercially available products include: Calfine 200M (light calcium carbonate, manufactured by Maruo Calcium Co., Ltd.), C-301N (aluminum hydroxide, manufactured by Sumitomo Chemical Co., Ltd.), Hughes Rex RY (molten silicon dioxide, manufactured by Ryusen Co., Ltd.), LS-210B (alumina, manufactured by Nippon Light Metals Co., Ltd.), Shinano Rundum GP (silicon carbide, manufactured by Shinano Electric Refining Co., Ltd.), Denka boron nitride HGP (boron nitride, manufactured by Denka Co., Ltd.), and Toyo Tecfiller TFZ-N05P (aluminum nitride, manufactured by Toyo Aluminum Co., Ltd.), etc. Among these inorganic fillers, those that improve the thermal conductivity of the cured material are preferably silicon dioxide, alumina, silicon carbide, boron nitride, and aluminum nitride, with silicon dioxide and alumina being more preferred. Furthermore, those that facilitate resin mixing and prevent viscosity increases are preferably calcium carbonate, aluminum hydroxide, fused silicon dioxide, and alumina, with aluminum hydroxide, silicon dioxide, and alumina being more preferred. Moreover, from the perspective of high market volume and stable product quality, those that are preferably calcium carbonate, aluminum hydroxide, silicon dioxide, and alumina, with aluminum hydroxide, fused silicon dioxide, and alumina being more preferred. Additionally, as silicon dioxide, fused silicon dioxide, obtained by completely melting high-purity quartz at high temperature to vitrify the quartz, is particularly preferred.

[0025] The inorganic filler particles used in this invention can be amorphous or spherical. Considering the viscosity of the resin composition or the sedimentation of the inorganic filler, coarse particles to microparticles can be combined and formulated, or only a single particle size can be used. The average particle size (D50) measured using a laser diffraction particle size distribution device is 0.2 μm to 50 μm, preferably 0.5 μm to 40 μm, and more preferably 1 μm to 30 μm. When the average particle size (D50) is less than 0.2 μm, there is a concern that the dispersion rate will be significantly reduced when preparing the epoxy resin composition. In addition, if the average particle size (D50) exceeds 50 μm, there is a concern that partial sedimentation will occur in the epoxy resin composition, and a homogeneous resin composition cannot be obtained. In addition, although there is no particular limitation, D98 is preferably 200 μm or less, and more preferably 100 μm or less. By using inorganic fillers with better particle size distribution, it is easy to suppress the sedimentation of inorganic fillers during the curing of epoxy resin compositions for injection molding, and the impregnation of electrical and electronic components such as coils will not be reduced.

[0026] Regarding the amount of inorganic filler used in this invention, the inorganic filler is 50 to 500 parts by weight relative to 100 parts by weight of epoxy resin, preferably 250 to 450 parts by weight, and more preferably 300 to 425 parts by weight. By setting the amount above the lower limit of the range, excellent mechanical properties (especially thermal shock resistance) and electrical properties can be obtained when the epoxy resin composition for injection molding is cured. In addition, by setting the amount below the upper limit of the range, good impregnation of coils, etc., can be obtained without reducing workability due to reduced fluidity.

[0027] Furthermore, in order to uniformly disperse the inorganic filler, it is preferable to formulate a dispersant into the resin composition of the present invention. As a dispersant, it can be widely used without particular limitation as long as it has an adsorption group for the inorganic filler and an affinity group for the resin. Examples include anionic compounds, cationic compounds, nonionic compounds, and polymeric compounds, which can be used alone or in combination of two or more. Among these, nonionic compounds and polymeric compounds are preferred, more preferably polymeric compounds, and even more preferably polycarboxylic acid polymeric compounds. As polycarboxylic acid polymeric compounds, partially esterified α-olefin / maleic anhydride copolymers can be listed. Commercially available examples include Florene G-700 and Florene GW-1500 (both manufactured by Kyoei Chemicals). From the perspective of balancing the settling properties and hardening properties of inorganic fillers, the amount of dispersant in the resin composition is preferably 0.1% to 10% by mass, more preferably 0.3% to 5.0% by mass, and even more preferably 0.5% to 3.0% by mass.

[0028] Furthermore, in addition to the above-mentioned components, a curing accelerator may also be formulated into the resin composition of the present invention as needed. The amount of curing accelerator added is typically in the range of 0.2 parts by weight to 10 parts by weight relative to 100 parts by weight of epoxy resin. As for the curing accelerator, there are no particular limitations as long as it has the function of promoting the reaction between epoxy resin and curing agent. Examples include imidazole compounds, tertiary amines, diazabicycloolefins and their derivatives, phosphine compounds, etc., which can be used alone or in combination of two or more.

[0029] Examples of imidazole compounds include: 2-ethyl-4-methylimidazolium, 2-methylimidazolium, 2-ethylimidazolium, 2-phenylimidazolium, 2-phenyl-4-methylimidazolium, 2-phenyl-4-hydroxymethylimidazolium, 1-cyanoethyl-2-methylimidazolium, 1-cyanoethyl-2-ethyl-4-methylimidazolium, 2-phenyl-4-methyl-5-hydroxymethylimidazolium, etc. Examples of tertiary amines include: triethylamine, triethylenediamine, benzyldimethylamine, α-methylbenzyldimethylamine, triethanolamine, dimethylaminoethanol, 2-(dimethylaminomethyl)phenol, tris(dimethylaminomethyl)phenol, etc. Examples of diazabicycloolefins and their derivatives include: 1,8-diazabicyclo[5,4,0]undecene-7 (DBU), 1,5-diazabicyclo[4,3,0]nonene-5, etc. Examples of phosphine derivatives include triethylphosphine, triphenylphosphine, and diphenylphosphine.

[0030] Furthermore, to the extent that it does not impede the effects of the invention, the resin composition of the present invention may be adjusted as needed to include a blending agent, a colorant such as carbon black or synthetic dye, an antifoaming agent, a leveling agent, a flame retardant, etc.

[0031] Next, the method for manufacturing the epoxy resin composition for injection molding according to the present invention will be described in detail. The epoxy resin composition for injection molding according to the present invention can be obtained by mixing and / or kneading an epoxy resin composition for injection molding containing a main component and a hardener component. More specifically, for example, the main component can be manufactured by mixing a portion of an inorganic filler and various components as needed in a bisphenol type epoxy resin. In addition, the hardener component can be manufactured by mixing residual components of the inorganic filler, a curing accelerator, and various components as needed in an acid anhydride. Subsequently, the main component and the hardener component can be mixed and / or kneaded using a mixer such as a mixer and / or a kneading machine such as a kneader or roller to obtain the epoxy resin composition for injection molding. The resin composition of the present invention can be used in either a single-component type where all components are mixed and stored, or a two-component type where the main component and the hardener component are stored separately and mixed during injection molding.

[0032] The epoxy resin composition for injection molding obtained in the manner described above can be given excellent reliability by being used for injection molding and insulating sealing of electrical and electronic parts such as electrical coils.

[0033] Next, the electrical and electronic component apparatus of the present invention will be described in detail. The electrical and electronic component apparatus of the present invention can be obtained by injection molding the epoxy resin composition for injection molding of the present invention into electrical and electronic components such as electrical coils and capacitors, and then curing them. Preferably, the epoxy resin composition for injection molding is vacuum degassed during and / or before and after injection molding. By performing vacuum degassed, air and other contaminants contained in the epoxy resin composition for injection molding are removed, and electrical and electronic components with fewer voids in the cured epoxy resin composition can be obtained. When injection molding is performed using the epoxy resin composition of the present invention, heating and curing are performed. In this case, the molding curing conditions are, for example, heating and curing at 80°C to 100°C for 4 to 8 hours, and then post-curing at 110°C to 150°C for 5 to 10 hours. [Example]

[0034] Hereinafter, specific examples and comparative examples are given to illustrate the present invention, but the present invention is not limited to these. Unless otherwise specified, "parts" means parts by mass, "%" means % by mass, and "ppm" means ppm by mass. The following describes the manufacturing method and the measurement method. In addition, the unit for various equivalents is "g / eq."

[0035] (1)Epoxy equivalent: Determined according to JIS K 7236 standard.

[0036] (2)Viscosity: Determined according to JIS K 7233 standard, 4.2 Single cylinder rotational viscometer method. Specifically, a Brookfield viscometer was used at 25°C. The unit is mPa·s.

[0037] (3)Content of epoxy resin with n=0 volume and total content of n=2 or more volumes: Determined by GPC measurement. Unit is area%. The following describes the GPC measurement conditions. (GPC measurement conditions) Apparatus: GPC-8220 system (manufactured by Tosoh Corporation) Column: TSK-GEL (manufactured by Tosoh Corporation) G2000HXL×2 + G1000HXL Temperature: 40℃ Dissolution solution: Tetrahydrofuran Flow rate: 1.0 mL / min Detector: RI Sample concentration: 0.1 g / 10 mL (tetrahydrofuran) Sample injection volume: 25 μL

[0038] (4)Glass transition temperature (Tg): Based on the JIS K 7121 standard and the method for measuring transition temperature, the temperature was measured using a differential scanning calorimeter (DSC) at a heating rate of 10℃ / min.

[0039] (5) Thermal shock resistance: Seven test pieces were prepared according to JIS C 2105 standard, 6.5.6.0A crack resistance test, and thermal cycling tests were conducted under the temperature cycling conditions shown in Table 1. The crack resistance of the test pieces was evaluated according to 6.5.6.0A. The number of cycles in which two or more cracks appeared in the seven test pieces was determined, and the following three-stage evaluation method was used for evaluation. ○: more than eleven cycles, △: seven to ten cycles, ×: less than six cycles

[0040] [Table 1] Cycle number Temperature cycling conditions Low temperature preservation High temperature maintenance Temperature (°C) Time (minutes) Temperature (°C) Time (minutes) 1 2 3 4 5 6 7 8 9 10 11 12 -10 -20 -30 -35 -40 -45 -50 -55 -60 -60 -60 -60 30 30 30 30 30 30 30 30 30 30 30 30 100 100 100 100 100 100 100 100 100 110 115 120 30 30 30 30 30 30 30 30 30 30 30 30

[0041] (6)Electrical characteristics (insulation): The volume resistivity of the hardened material at 120°C was measured according to JIS K 6911 standard, and evaluated using the following two-stage evaluation method. ○: Volume resistivity at 120°C is 10¹³ Ω·cm or higher ×: Volume resistivity at 120°C is less than 10¹³ Ω·cm

[0042] (7)Injectionability: 150 g of the epoxy resin composition for injection molding is heated at 70°C and immediately poured vertically into a mold (gap 4 mm, size 160 mm × 180 mm) preheated to 90°C under normal pressure. The time (in minutes) until the injection is completed in the mold is measured. Furthermore, the case where injection is completely impossible is marked as "×".

[0043] The abbreviations used in the examples and comparative examples are explained as follows. [Epoxy Resin] R1~R7, RH1~RH4: Epoxy resins obtained in Synthetic Examples 1~Synthetic Examples 7, Comparative Synthetic Examples 1~Comparative Synthetic Examples 4 A1: Bisphenol A type liquid epoxy resin (manufactured by Nippon Steel Chemical & Materials Co., Ltd., Epotohto YD-128, epoxy equivalent 187, n=0 volume content 80 area%, total content of n=2 or more volumes 2 area%) A2: Bisphenol F type liquid epoxy resin (manufactured by Nippon Steel Chemical & Materials Co., Ltd., Epotohto YDF-170, epoxy equivalent 167 g / eq., n=0 volume content 70 area%, total content of n=2 or more volumes 0.2 area%) A3: Tetramethylbisphenol F type crystalline epoxy resin (manufactured by Nippon Steel Chemical & Materials Co., Ltd., Epotohto YSLV-80XY, epoxy equivalent 187, n=0 component content 92 area%, total content of n=2 or more components 0.3 area%, melting point 80℃) A4: Bisphenol F type solid epoxy resin (manufactured by Nippon Steel Chemical & Materials Co., Ltd., Epotohto YDF-2001, epoxy equivalent 485, n=0 component content 10 area%, total content of n=2 or more components 75 area%) A5: Bisphenol F type solid epoxy resin (manufactured by Nippon Steel Chemical & Materials Co., Ltd., Epotohto YDF-2004, epoxy equivalent 950, n=0 component content 4 area%, total content of n=2 or more components 90 area%) A6: Bisphenol A type solid epoxy resin (manufactured by Nippon Steel Chemicals & Materials Co., Ltd., Epotohto YD-012, epoxy equivalent 620, n=0 bulk content 5% area%, total content of n=2 or more bulks 85% area)

[0044] [Curing Agent] B1: 3 or 4-methyl-1,2,3,6-tetrahydrophthalic anhydride (manufactured by Hitachi Chemical Co., Ltd., HN-2200R, viscosity at 25°C = 70 mPa·s)

[0045] [Inorganic Filler Material] C1: Aluminum hydroxide (manufactured by Sumitomo Chemical Co., Ltd., C-301N, BET specific surface area = 4.0 m2 / g, D50 = 1.5 μm, D98 = 64 μm) C2: Fused silicon dioxide (manufactured by Ryusei Corporation, Hughes Rex SY, D50 = 20 μm, D98 = 96 μm) C3: Fused silicon dioxide (manufactured by Ryusei Corporation, Hughes Rex RD-20, D50 = 7 μm, D98 = 32 μm)

[0046] [Curing Accelerator] D1: 1-Benzyl-2-methylimidazol (manufactured by Shikoku Chemical Industry Co., Ltd., Curezol 1B2MZ)

[0047] [Other Additives] E1: Dispersant (manufactured by Kyoei Chemical Co., Ltd., Florene G-700, weight average molecular weight 2,700, acid value 60 mgKOH / g) E2: Defoamer (manufactured by Momentive Performance Materials Japan, TSA720) E3: Wetting and dispersing agent (manufactured by BYK-Chemie, BYK-110) E4: Silicon coupling agent (manufactured by Momentive Performance Materials Japan, TSL-8350) E5: Colorant (manufactured by Mitsubishi Chemical Co., Ltd., MA-8)

[0048] Synthesis Example 1 In a reaction vessel including a stirrer and a nitrogen inlet pipe, 85 parts of A1 and 18 parts of A4 were charged at room temperature. Nitrogen gas was introduced while the temperature was raised to 100°C and the mixture was uniformly mixed to obtain epoxy resin (R1).

[0049] Synthesis Examples 2 to 6 and Comparative Synthesis Examples 1 to 4 were performed in the same manner as in Synthesis Example 1 according to the amount (parts) of each raw material shown in Table 2, thereby obtaining epoxy resin (R2 to R6) and epoxy resin (RH1 to RH4).

[0050] Synthesis Example 7: In a reaction vessel including a stirrer, a thermometer, and a nitrogen inlet device, 159 parts of Al and 41 parts of bisphenol F (manufactured by Nippon Steel Chemical & Materials Co., Ltd.) were charged at room temperature. While stirring with nitrogen, the mixture was heated to 130°C. 0.2 parts of n-butyltriphenylphosphonium bromide were added, and the temperature was raised to 160°C. The reaction was carried out at this temperature for 2 hours. Afterwards, 800 parts of Al were charged, and the reaction was carried out again at 160°C for 2 hours to obtain epoxy resin (R7).

[0051] [Table 2] Synthesis example Comparative Synthesis Example 1 2 3 4 5 6 7 1 2 3 4 A1 85 75 85 80 80 96 65 A2 10 88 75 75 A3 10 A4 15 25 10 35 25 A5 15 10 4 A6 12 25 Epoxy resin R1 R2 R3 R4 R5 R6 R7 RH1 RH2 RH3 RH4 Epoxy equivalent (g / eq.) 206 221 213 203 197 183 212 193 238 200 204 viscosity (mPa·s) 70000 98000 80000 75000 61000 60000 80000 50000 150000 70000 110000 n=0 body content (area%) 68.6 62.5 68.6 73.6 72.0 62.2 67.0 77.0 55.5 55.0 53.8 n=2 or more contents (area%) 13.0 20.3 15.2 10.6 9.1 12.0 16.0 5.5 27.6 18.9 21.4

[0052] Example 1 100 parts of epoxy resin (R1) obtained in Synthesis Example 1, 80 parts of B1, 12 parts of C1, 22 parts of C2, 230 parts of C3, 0.5 parts of D1, 6 parts of E1, 0.2 parts of E2, 1.9 parts of E3, 0.5 parts of E4, and 1 part of E5 were vacuum mixed at room temperature for 1 hour to obtain an epoxy resin composition for injection molding.

[0053] The obtained epoxy resin composition for injection molding is cured at 80°C for 6 hours + 130°C for 10 hours to obtain a cured product.

[0054] Examples 2 to 7 and Comparative Examples 1 to 4 were prepared according to the same procedures as in Example 1, using the amounts (parts) of each raw material shown in Table 3, to obtain epoxy resin compositions for injection molding and cured products. Furthermore, the mixing amounts of C1, C2, C3, D1, E1, E2, E3, E4, and E5 were the same as in Example 1.

[0055] The injection molding properties, Tg, thermal shock resistance, and insulation properties measured using the epoxy resin compositions for injection molding obtained in Examples 1 to 7 and Comparative Examples 1 to 4 are shown in Table 3.

[0056] [Table 3] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Epoxy resin R1 R2 R3 R4 R5 R6 R7 RH1 RH2 RH3 RH4 100 100 100 100 100 100 100 100 100 100 100 Hardener B1 80 75 78 82 84 91 78 86 70 83 81 C1 12 C2 twenty two C3 230 D1 0.5 E1 6 E2 0.2 E3 1.9 E4 0.5 E5 1 Injection molding time (minutes) 3.3 5.2 4.1 3.1 2.5 2.8 3.3 2.1 × 3.5 × Tg (°C) 126 120 122 126 127 129 125 127 120 125 128 Thermal shock resistance ○ ○ ○ ○ ○ ○ ○ × ○ × ○ insulation ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ×

[0057] As confirmed by Table 3, the epoxy resin composition for injection molding of the present invention exhibits excellent impregnation (injection molding properties) and can produce a cured product with excellent thermal shock resistance. [Industrial Applicability]

[0058] The epoxy resin composition for injection molding of the present invention can impart excellent reliability by being used for injection molding and insulating sealing of electrical and electronic parts, and is useful, for example, in the manufacture of small motors or ignition coils for automobiles. [Simplified Explanation of the Diagram]

[0060] None

Claims

1. An epoxy resin composition for injection molding, comprising epoxy resin, an anhydride-based curing agent, inorganic filler, and dispersant, wherein the epoxy resin is a bisphenol type epoxy resin represented by the following general formula (1), the epoxy resin is a mixture of low molecular weight bisphenol A type liquid epoxy resin and medium molecular weight bisphenol F type solid epoxy resin, the epoxy equivalent is 185 g / eq.~225 g / eq., in gel permeation chromatography determination, the content of n=0 particles is 60 area%~75 area%, the total content of n=2 particles and above is 5 area%~25 area%, the average particle size (D50) of the inorganic filler is 0.2 μm~50 μm, and the inorganic filler is 50 parts by mass to 500 parts by mass relative to 100 parts by mass of epoxy resin, the dispersant has an adsorption group of inorganic filler and a resin affinity group, and the amount of dispersant in the resin composition is 0.1% by mass to 10% by mass.

1. In the formula, R1 and R2 are independently hydrogen atoms or hydrocarbon groups with 1 to 6 carbon atoms, and n is the number of repetitions, with an average of 0.5 to 5.

2. The epoxy resin composition for injection molding as claimed in claim 1, wherein the viscosity of the epoxy resin at 25°C is 60,000 mPa·s to 100,000 mPa·s.

3. The epoxy resin composition for injection molding as claimed in claim 1, wherein the anhydride-based curing agent is liquid and has a viscosity of 30 mPa·s to 500 mPa·s at 25°C.

4. An electrical and electronic component, characterized in that it is injection molded from an epoxy resin composition for injection molding as described in claim 1.