Thermally-conductive resin composition and cured resin product

Abstract

The present disclosure addresses the problem of providing a thermally-conductive resin composition that is capable of improving fluidity while enhancing thermal conductivity of a cured resin product, and that is excellent in storage stability. The thermally-conductive resin composition of the present disclosure contains the following components (A) to (E). (A) An epoxy resin having a viscosity of 100 Pa·s or less at 25°C (B) An acid anhydride (C) A curing accelerator having a melting point of 150°C or more, or a softening point of 100°C or more (D) A dispersant having a polystyrene-equivalent weight-average molecular weight of 2,000 or more as measured by gel permeation chromatography (E) A filler having a thermal conductivity of 10W / m·K or more

Description

Thermally Conductive Resin Composition and Cured Resin Product

[0001] The present disclosure relates to a thermally conductive resin composition and a cured resin product, and specifically relates to a thermally conductive resin composition containing an epoxy resin and a cured resin product of the thermally conductive resin composition.

[0002] In recent years, with the miniaturization and higher density of electronic devices, the amount of heat generated by electronic components has tended to increase remarkably, and the demand for materials capable of efficiently dissipating such generated heat has increased sharply. To efficiently dissipate and remove the generated heat to the outside, heat dissipation members formed of a resin composition containing a thermally conductive inorganic powder are used. The heat dissipation members used in this case are required to be materials that have advantages over conventional materials not only in thermal conductivity but also in moldability and cost.

[0003] Patent Document 1 discloses a thermally conductive resin composition. This thermally conductive resin composition comprises (A) an epoxy resin, (B) an adduct-type latent curing agent that is solid at 25°C, and (C) a mixture of (C1) a thermally conductive powder having an average particle diameter of 0.01 µm or more and less than 2 µm, (C2) a thermally conductive powder having an average particle diameter of 2 µm or more and less than 20 µm, and (C3) a thermally conductive powder having an average particle diameter of 20 µm or more and less than 150 µm, wherein the mass ratio of component (C1) to component (C3) is 0.14 to 1.0, and the mass ratio of component (C2) to component (C3) is 0.25 to 1.5. According to the thermally conductive resin composition of Patent Document 1, it is described that a cured product excellent in low-temperature curability, handleability, and thermal conductivity can be formed.

[0004] However, in the above conventional thermally conductive resin composition, when the addition amount of the thermally conductive powder is increased to achieve higher thermal conductivity, the dispersibility and dispersion stability of the thermally conductive powder decrease, or the viscosity of the composition increases remarkably, resulting in decreased fluidity, which may lead to poor handleability and workability. In addition, these compositions are also required to have good storage stability.

[0005] International Publication No. 2019 / 078044

[0006] The object of this disclosure is to provide a thermally conductive resin composition that can improve the thermal conductivity of a cured resin product while also improving its fluidity and providing excellent storage stability, as well as a cured resin product of this thermally conductive resin composition.

[0007] A thermally conductive resin composition according to one aspect of the present disclosure contains the following components (A) to (E): (A) an epoxy resin having a viscosity of 100 Pa·s or less at 25°C; (B) an acid anhydride; (C) a curing accelerator having a melting point of 150°C or higher or a softening point of 100°C or higher; (D) a dispersant having a weight-average molecular weight of 2000 or more on a polystyrene basis as measured by gel permeation chromatography; and (E) a filler having a thermal conductivity of 10 W / m·K or higher.

[0008] A resin cured product according to one aspect of the present disclosure is obtained by heating the thermally conductive resin composition.

[0009] 1. Overview The thermally conductive resin composition according to this embodiment (hereinafter also referred to as composition (X)) contains (A) an epoxy resin having a viscosity of 100 Pa·s or less at 25°C (hereinafter also referred to as epoxy resin (A)), (B) an acid anhydride (hereinafter also referred to as acid anhydride (B)), (C) a curing accelerator having a melting point of 150°C or higher or a softening point of 100°C or higher (hereinafter also referred to as curing accelerator (C)), (D) a dispersant having a weight-average molecular weight of 2000 or more in terms of polystyrene as measured by gel permeation chromatography (hereinafter also referred to as dispersant (D)), and (E) a filler having a thermal conductivity of 10 W / m·K or higher (hereinafter also referred to as filler (E)). Furthermore, the cured resin product according to this embodiment (hereinafter also referred to as cured resin product (Y)) is obtained by heating composition (X).

[0010] The inventors, after diligently studying thermally conductive resin compositions to solve the above-mentioned problems, discovered that there is a relationship between the properties of the curing accelerator (C) and dispersant (D) contained in the composition and the properties of the resulting thermally conductive resin composition, such as its fluidity, storage stability, and the thermal conductivity of the cured resin product (Y), and thus completed this disclosure.

[0011] Composition (X) enhances the thermal conductivity of the cured resin product, improves its fluidity, and provides excellent storage stability. The reason why composition (X) achieves the above effects with the above configuration is not entirely clear, but it can be inferred, for example, as follows: By using a dispersant (D) with a weight-average molecular weight above a specific value, in addition to the epoxy resin (A), the acid anhydride (B) as a curing agent, and the filler (E) having a thermal conductivity above a specific value, it is thought that the dispersibility of the filler (E) and other components in composition (X) can be improved. Furthermore, by using a curing accelerator (C) having a melting or softening point above a specific temperature, the curing reaction at room temperature can be suppressed, improving storage stability. In addition, by allowing the curing accelerator (C) to remain in the system during the curing reaction, it is possible to easily form heat conduction paths for the highly thermally conductive filler, thereby improving the thermal conductivity of the cured resin product (Y). Thus, composition (X) can improve fluidity, storage stability, and the thermal conductivity of the cured resin product (Y).

[0012] Thus, according to this disclosure, it is possible to provide a thermally conductive resin composition that can improve fluidity while increasing the thermal conductivity of the cured resin product, and also has excellent storage stability, as well as a cured resin product of this thermally conductive resin composition.

[0013] 2. Details <Thermal Conductivity Resin Composition> Composition (X) contains epoxy resin (A), acid anhydride (B), curing accelerator (C), dispersant (D), and filler (E). Composition (X) may further contain other components other than components (A) to (E) as long as the effects of this disclosure are not impaired. Each component is described below.

[0014] [Epoxy Resin (A)] Epoxy resin (A) is a compound having one or more epoxy groups in one molecule. It is preferable to use a compound having two or more epoxy groups in one molecule as epoxy resin (A).

[0015] Examples of epoxy resins (A) include bisphenol-type epoxy resins, hydrogenated bisphenol-type epoxy resins, biphenyl-type epoxy resins, naphthalene ring-containing epoxy resins, alicyclic epoxy resins, dicyclopentadiene-type epoxy resins, phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, triphenylmethane-type epoxy resins, aliphatic epoxy resins, triglycidyl isocyanurate, glycidyl group-containing silicone resins, and glycidylamine-type epoxy resins.

[0016] The proportion of epoxy resin (A) is preferably 1% by mass or more, and more preferably 4% by mass or more, relative to the total composition (X). The proportion of epoxy resin (A) is preferably 15% by mass or less, and more preferably 8% by mass or less. In this case, the fluidity of composition (X) can be further improved.

[0017] [Acid anhydride (B)] Acid anhydride (B) is a compound having one or more acid anhydride groups (-CO-O-CO-) in a single molecule. Acid anhydride (B) acts as a curing agent that reacts with epoxy resin (A), for example.

[0018] Examples of acid anhydrides (B) include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, dodecenyl succinic anhydride, polyadipic anhydride, polyazelaic anhydride, polysebacic anhydride, poly(ethyloctadecanediic acid) anhydride, poly(phenylhexadecanedioic acid) anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, and trialkyltetrahydro Examples include phthalic anhydride, methylcyclohexenedicarboxylic acid anhydride, methylcyclohexenetetracarboxylic acid anhydride, ethylene glycol bistrimellitate dianhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexane-1,2-dicarboxylic acid anhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalenesuccinic acid dianhydride, or 1-methyl-dicarboxy-1,2,3,4-tetrahydro-1-naphthalenesuccinic acid dianhydride.

[0019] The ratio of the equivalent weight of acid anhydride (B) to one equivalent weight of epoxy resin (A) is, for example, 0.6 or more and 1.4 or less.

[0020] The amount of acid anhydride (B) is preferably 80 parts by mass or more, and more preferably 100 parts by mass or more, per 100 parts by mass of epoxy resin (A). The amount of acid anhydride (B) is preferably 150 parts by mass or less, and more preferably 120 parts by mass or less.

[0021] The proportion of acid anhydride (B) is preferably 1% by mass or more, and more preferably 5% by mass or more, relative to the total composition (X). The proportion of acid anhydride (B) is preferably 20% by mass or less, and more preferably 10% by mass or less.

[0022] [Curing accelerator (C)] The curing accelerator (C) is an ingredient that accelerates the curing reaction between epoxy resin (A) and acid anhydride (B).

[0023] Examples of curing accelerators (C) include tertiary amines, imidazoles, organophosphines, cycloamidines, tetrasubstituted phosphonium / tetrasubstituted borates, and tetraphenylboron salts.

[0024] It is important that the curing accelerator (C) has a melting point of 150°C or higher or a softening point of 100°C or higher. That is, if the curing accelerator (C) is a crystalline compound or the like and has a melting point, this melting point must be 150°C or higher, and if the curing accelerator (C) is an amorphous substance or the like and has a softening point, this softening point must be 100°C or higher.

[0025] The melting point of the curing accelerator (C) is preferably 160°C or higher, and more preferably 170°C or higher. The melting point of the curing accelerator (C) is, for example, 250°C or lower.

[0026] The softening point of the curing accelerator (C) is preferably 110°C or higher, and more preferably 120°C or higher. The softening point of the curing accelerator (C) is, for example, 250°C or lower.

[0027] By setting the melting or softening point of the curing accelerator (C) within the above range, both the storage stability of the composition (X) and the thermal conductivity of the cured resin product (Y) can be further improved.

[0028] Examples of commercially available curing accelerators (C) include MY-24, MY-25, PN-23, PN-31, PN-40, PN-50, PN-H (all manufactured by Ajinomoto Fine Techno Co., Ltd.), FXR-1081, FXR-1121 (both manufactured by T&K Toka Co., Ltd.), and Curesol 2MA-OK, 2PHZ-PW, 2P4MZ (all manufactured by Shikoku Chemicals Co., Ltd.).

[0029] The amount of curing accelerator (C) is preferably 0.1 parts by mass or more, and more preferably 0.3 parts by mass or more, per 100 parts by mass of acid anhydride (B). The amount of curing accelerator (C) is preferably 1 part by mass or less, and more preferably 0.5 parts by mass or less.

[0030] The proportion of the curing accelerator (C) is preferably 0.005% by mass or more, and more preferably 0.02% by mass or more, relative to the total composition (X). The proportion of the curing accelerator (C) is preferably 0.1% by mass or less, and more preferably 0.05% by mass or less.

[0031] [Dispersant (D)] Dispersant (D) is a component in composition (X) that improves the dispersibility of filler (E) and the like. Dispersant (D) may consist of a single compound or a composition consisting of two or more compounds.

[0032] It is important that the weight-average molecular weight (Mw) of the dispersant (D), measured by gel permeation chromatography, is 2000 or more in terms of polystyrene. Preferably, the Mw of the dispersant (D) is 2500 or more, more preferably 4000 or more, and even more preferably 6000 or more. For example, the Mw of the dispersant (D) is 100,000 or less. By setting the Mw of the dispersant (D) within the above range, the storage stability and fluidity of composition (X) can be further improved.

[0033] The Mw of the dispersant (D) is measured by gel permeation chromatography (GPC) under the following conditions: GPC instrument: HLC-8220GPC (Tosoh Corporation) GPC column: Two TSK-GEL SUPERHZM-N columns in series (Tosoh Corporation) Temperature: 40°C Eluent: Tetrahydrofuran Flow rate: 0.35 mL / min Sample concentration: 1% by mass Sample injection volume: 20 μL Detector: Differential refractometer Standard material: Monodisperse polystyrene

[0034] Examples of commercially available dispersants (D) include DISPERBYK-145, DISPERBYK-9076, DISPERBYK-142, DISPERBYK-2013, DISPERBYK-2055, DISPERBYK-2152 (all manufactured by BYK Chemie), HIPLAAD ED-251, HIPLAAD ED-152 (both manufactured by Kusumoto Chemical Co., Ltd.), and mixtures of HIPLAAD ED-152 (manufactured by Kusumoto Chemical Co., Ltd.) and DISPERBYK-2055 (manufactured by BYK Chemie).

[0035] The dispersant (D) preferably has an acid value greater than 0 mgKOH / g and an amine value greater than 0 mgKOH / g. That is, it is preferable to use a dispersant (D) that has an acid value greater than 0 mgKOH / g and an amine value greater than 0 mgKOH / g. Having an acid value greater than 0 mgKOH / g and an amine value greater than 0 mgKOH / g in the dispersant (D) can further improve the thermal conductivity of the resin cured product (Y).

[0036] "Acid value" refers to the number of mg of potassium hydroxide required to neutralize acidic groups such as carboxyl groups and phosphate groups contained in 1 g of dispersant (unit: mgKOH / g). "Amine value" refers to the number of mg of hydrochloric acid and equimolar potassium hydroxide required to neutralize basic groups such as amino groups and phosphate bases contained in 1 g of dispersant (unit: mgKOH / g). The acid value can be measured by a known acid value measurement method, for example, a method conforming to JIS-K-0070-1992, and the amine value can be measured by a known amine value measurement method, for example, a method conforming to JIS-K-7237-1995.

[0037] The dispersant (D) may consist of one compound having an acid value and an amine value, or it may be a mixture of a compound having an acid value but no amine value and a compound having an amine value but no acid value.

[0038] The acid value of the dispersant (D) is preferably 10 mg KOH / g or more, and more preferably 30 mg KOH / g or more. The acid value of the dispersant (D) is preferably 100 mg KOH / g or less, and more preferably 80 mg KOH / g or less.

[0039] The amine value of the dispersant (D) is preferably 10 mg KOH / g or more, more preferably 20 mg KOH / g or more, and even more preferably 40 mg KOH / g or more. The amine value of the dispersant (D) is preferably 100 mg KOH / g or less, and more preferably 80 mg KOH / g or less.

[0040] By setting the acid value and amine value of the dispersant (D) within the above range, the fluidity and storage stability of composition (X), as well as the thermal conductivity of the cured resin product (Y), can be further improved.

[0041] Examples of dispersants (D) include those having both an acid value and an amine value, such as phosphate ester salts, phosphate esters, and ammonium salts. Alternatively, dispersant (D) may be a mixture of, for example, a carboxylic acid system having an acid value but no amine value and a pigment affinity group-containing copolymer system having an amine value but no acid value.

[0042] The amount of dispersant (D) is preferably 100 parts by mass or more, more preferably 200 parts by mass or more, and even more preferably 300 parts by mass or more, per 100 parts by mass of curing accelerator (C). The amount of dispersant (D) is preferably 2000 parts by mass or less, more preferably 1000 parts by mass or less, and even more preferably 800 parts by mass or less. In this case, the fluidity and storage stability of composition (X), and the thermal conductivity of the cured resin product (Y) can be further improved.

[0043] The amount of the dispersant (D) is preferably 0.01 parts by mass or more, and more preferably 0.1 parts by mass or more, relative to 100 parts by mass of the filler (E). The amount of the dispersant (D) is preferably 1 part by mass or less, and more preferably 0.3 parts by mass or less.

[0044] The proportion of the dispersant (D) is preferably 0.01% by mass or more, and more preferably 0.04% by mass or more, relative to the entire composition (X). The proportion of the dispersant (D) is preferably 1% by mass or less, and more preferably 0.4% by mass or less.

[0045] [Filler (E)] The filler (E) refers to a filler having a thermal conductivity of 10 W / m·K or higher, that is, it means a highly thermally conductive filler.

[0046] The thermal conductivity of the filler (E) is preferably 12 W / m·K or higher, more preferably 15 W / m·K or higher, and still more preferably 30 W / m·K or higher. In this case, the thermal conductivity of the cured resin (Y) can be further improved. The thermal conductivity of the filler (E) is, for example, 50 W / m·K or lower.

[0047] Examples of the filler (E) include inorganic fillers, organic fillers, and the like. Among these, inorganic fillers are preferable.

[0048] Examples of materials for the inorganic filler include crystalline silica, aluminum oxide, aluminum nitride, aluminum, silicon nitride, silicon carbide, zinc oxide, magnesium oxide, silver, copper, boron nitride, magnesium carbonate, anhydrous magnesium carbonate, graphite, carbon nanotubes, graphene, and the like.

[0049] The filler (E) preferably contains at least one of alumina and aluminum nitride. In this case, the thermal conductivity of the cured resin (Y) can be further improved.

[0050] The filler (E) may be surface-treated in advance using a surface treatment agent such as a coupling agent.

[0051] The volume-average particle size of the filler (E) is preferably, for example, 0.1 μm or more and 100 μm or less, and more preferably 1 μm or more and 50 μm or less. The volume-average particle size of the filler (E) is the value measured as the particle diameter (d50) when the cumulative value from the smallest diameter side reaches 50% in the volume-based particle size distribution measured by a laser diffraction scattering particle size distribution analyzer.

[0052] One or more types of filler (E) can be used. That is, two or more types with different volume-average particle sizes may be used. In this case, the volume-average particle size of one can be, for example, 0.1 μm or more and less than 10 μm, and the volume-average particle size of the other can be, for example, 10 μm or more and 100 μm or less.

[0053] The proportion of filler (E) is preferably 80% by mass or more, more preferably 83% by mass or more, even more preferably 88% by mass or more, and particularly preferably 90% by mass or more, relative to the entire composition (X). For example, the proportion of filler (E) is 95% by mass or less. In this case, the thermal conductivity of the cured resin product (Y) can be further improved.

[0054] [Other components] Other components include, for example, solvents, curing agents other than acid anhydride (B), coupling agents, release agents, flame retardants, flame retardant aids, ion trapping agents, pigments, colorants, stress reducers, tackifiers, and silicone flexible agents.

[0055] Other curing agents include, for example, phenol-based curing agents.

[0056] Composition (X) typically does not contain a solvent. Because composition (X) does not contain a solvent, a drying step after application is unnecessary.

[0057] If composition (X) contains other components, the proportion of these other components is, for example, 1% by mass or less relative to the entire composition (X).

[0058] Composition (X) can be prepared by blending, for example, epoxy resin (A), acid anhydride (B), curing accelerator (C), dispersant (D), filler (E), and other components as needed, and stirring and mixing them. In this case, it is preferable to first blend components (A) to (D), stir and mix them, then add the filler (E), stir and mix, and then further mix using a three-roll mixer or the like.

[0059] Composition (X) has improved fluidity. The viscosity of composition (X) at 25°C is preferably 40 Pa·s or less, more preferably 30 Pa·s or less, and even more preferably 25 Pa·s or less. The viscosity of composition (X) is, for example, 1 Pa·s or more.

[0060] Composition (X) has excellent storage stability. The life of composition (X), that is, the time until solidification when left at 25°C, is preferably more than 12 hours, and more preferably 24 hours or more.

[0061] The composition (X) according to this embodiment has excellent fluidity, making it suitable for applications that fill small gaps or require a high filling rate. Furthermore, since the resin cured product (Y) obtained from composition (X) has excellent thermal conductivity, it can be suitably used for heat dissipation applications in electronic components such as power devices, transistors, thyristors, CPUs (central processing units), and GPUs (graphics processing units), as well as for heat dissipation applications in industrial components such as motors.

[0062] <Cured Resin Product> The cured resin product (Y) is a cured product of composition (X). Composition (X) hardens by heating, and the cured resin product (Y) is obtained. The heating temperature is preferably 100°C to 200°C, and more preferably 120°C to 180°C. The heating time is preferably 60 minutes to 300 minutes, and more preferably 120 minutes to 240 minutes. By heating composition (X) under the above conditions, the thermal conductivity of the cured resin product (Y) can be further improved.

[0063] Examples of methods for heating composition (X) include using known dryers such as drying ovens, vacuum ovens, air circulation ovens, hot air dryers, far-infrared dryers, microwave vacuum dryers, and high-frequency dryers.

[0064] The cured resin (Y) has high thermal conductivity. The thermal conductivity of the cured resin (Y) is preferably 4.5 W / m·K or higher, more preferably 5 W / m·K or higher, even more preferably 5.5 W / m·K or higher, particularly preferably 6 W / m·K or higher, and even more preferably 6.5 W / m·K or higher. The thermal conductivity of the cured resin (Y) is, for example, 8 W / m·K or lower.

[0065] The present disclosure will be further described below with reference to examples, but the present disclosure is not limited to these examples.

[0066] <Preparation of Thermally Conductive Resin Composition> The raw materials of the type and mass parts shown in Table 1 below, epoxy resin (A), acid anhydride (B), curing accelerator (C), and dispersant (D), were blended and stirred at 2000 rpm for 30 seconds. Then, a filler (E) was added and stirred at 2000 rpm for 1 minute, and then mixed three times with a three-roll mixer to obtain a paste-like thermally conductive resin composition. Details of the raw materials are as follows.

[0067] (Epoxy resin (A)) - A1: "Celoxide 2021P" manufactured by Daicel Corporation (alicyclic epoxy resin: 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate) (viscosity (25°C): 240 mPa·s, epoxy equivalent: 130 g / eq) - A2: "jER807" manufactured by Mitsubishi Chemical Corporation (bisphenol-type epoxy resin: bisphenol F diglycidyl ether) (viscosity (25°C): 3-4.5 Pa·s, epoxy equivalent: 160-175 g / eq) - A3: "YED216D" manufactured by Mitsubishi Chemical Corporation (aliphatic epoxy resin: hexanediol diglycidyl ether) (viscosity (25°C): 10-16 mPa·s, epoxy equivalent: 110-130 g / eq)

[0068] (Acid anhydride (B)) - B1: HN-2200 manufactured by Resonaq Corporation (3 or 4-methyl-1,2,3,6-tetrahydrophthalic anhydride)

[0069] (Curing accelerator (C)) -C1: "MY-25" manufactured by Ajinomoto Fine Techno Co., Ltd. (tertiary amine) (softening point: 110-150°C) -C2: "PN-50" manufactured by Ajinomoto Fine Techno Co., Ltd. (imidazole) (softening point: 100-125°C) -C3: "FXR-1121" manufactured by T&K Toka Co., Ltd. (imidazole) (softening point: >100°C) -C4: "Curesol 2MA-OK" manufactured by Shikoku Chemicals Co., Ltd. (imidazole: 2,4-diamino-6-(2'-methylimidazolyl)ethyl-s-triazine isocyanurate addition salt) (melting point: 260°C) -c1: "Cureazole 2E4MZ" manufactured by Shikoku Chemicals Co., Ltd. (Imidazole: 2-ethyl-4-methylimidazole) (Melting point: 51°C) -c2: "Cureazole C17Z" manufactured by Shikoku Chemicals Co., Ltd. (Imidazole: 2-heptadecylimidazole) (Melting point: 89°C) -c3: "Cureazole 2MH-Z" manufactured by Shikoku Chemicals Co., Ltd. (Imidazole: 2-methylimidazole) (Melting point: 145°C) -c4: Triphenylphosphine (organophosphine) (Melting point: 81°C)

[0070] (Dispersant (D)) (The units for the acid value and amine value shown below are mgKOH / g.) (Below, "BYK-" indicates "DISPERBYK-", a product of BYK Chemie. Below, "ED-" indicates "HIPLAD ED-", a product of Kusumoto Chemical Co., Ltd.) -D1: "BYK-145" (phosphate ester type) (Acid value: 76, Amine value: 71) -D2: "BYK-9076" (ammonium salt type) (Acid value: 38, Amine value: 44) -D3: "BYK-142" (phosphate ester type) (Acid value: 46, Amine value: 43) -D4: "ED-251" (phosphate ester type) (Acid value: 14, Amine value: 20) - D5: A mixture of D1 and "BYK-2055" (pigment affinity group-containing copolymer) (amine value: 40) in a mass ratio of 1:1 (acid value: 7, amine value: 20) - D6: "ED-152" (phosphate ester) (acid value: 14) - D7: "BYK-2152" (superbranched polyester) (no acid value or amine value) - d1: "Esream C-2093I" (carboxylic acid) (manufactured by NOF Corporation) (acid value: 105) (weight-average molecular weight: 1800)

[0071] (Filler (E)) (Alumina filler) (Manufactured by Denka Co., Ltd.) - E1: "DAW-90" (d50: 90 μm) - E2: "DAS-45" (d50: 40 μm) - E3: "DAW-20" (d50: 24 μm) - E4: "DAS-10" (d50: 14 μm) - E5: "DAW-01" (d50: 2 μm) (Aluminium nitride filler) (Manufactured by Tokuyama Co., Ltd.) - E6: "HFS-120" (d50: 120 μm) - E7: "HFS-30" (d50: 30 μm) - E8: "HFS-01" (d50: 1.1 μm)

[0072] <Evaluation> The storage stability, fluidity, and thermal conductivity of the cured resin composition prepared above were measured and evaluated using the following methods. The evaluation results are shown in Table 1 below.

[0073] [Storage Stability] The thermally conductive resin composition was left at 25°C, and the time until solidification was measured to determine its shelf life. Storage stability was evaluated according to the following criteria: A (Good): Shelf life was 24 hours or more. B (Fairly Good): Shelf life was between 12 hours and less than 24 hours. C (Poor): Shelf life was 12 hours or less.

[0074] [Fluidity] The viscosity of the thermally conductive resin composition was measured using an E-type viscometer at 25°C and 10 rpm. Fluidity was evaluated according to the following criteria: A (Good): Viscosity was 40 Pa·s or less. B (Fairly Good): Viscosity was greater than 40 Pa·s and less than 60 Pa·s. C (Poor): Viscosity was 60 Pa·s or more.

[0075] [Thermal Conductivity] A resin curing product was obtained by heating a thermally conductive resin composition at 150°C for 180 minutes. The thermal conductivity of this resin curing product was measured by the laser flash method. Thermal conductivity was evaluated according to the following criteria: A (Good): Thermal conductivity was 5 W / m·K or higher. B (Fairly Good): Thermal conductivity was less than 5 W / m·K but 4.5 W / m·K or higher. C (Poor): Thermal conductivity was less than 4.5 W / m·K.

[0076]

[0077] As can be seen from the results in Table 1, the thermally conductive resin composition of the example can improve fluidity while increasing the thermal conductivity of the cured resin, and also exhibits excellent storage stability. On the other hand, the thermally conductive resin composition of the comparative example is inferior to the example in at least one of the following: fluidity, storage stability, and thermal conductivity of the cured resin.

[0078] (Summary) As is clear from the above embodiments, the present disclosure includes the following embodiments. The thermally conductive resin composition of the first embodiment contains the following components (A) to (E): (A) an epoxy resin having a viscosity of 100 Pa·s or less at 25°C, (B) an acid anhydride, (C) a curing accelerator having a melting point of 150°C or higher or a softening point of 100°C or higher, (D) a dispersant having a weight-average molecular weight of 2000 or more in terms of polystyrene as measured by gel permeation chromatography, and (E) a filler having a thermal conductivity of 10 W / m·K or higher.

[0079] According to the first embodiment, the composition (X) can improve the fluidity of the resin cured product (Y) while increasing its thermal conductivity, and also exhibits excellent storage stability.

[0080] In the second embodiment of the thermally conductive resin composition, in the first embodiment, the proportion of (A) epoxy resin is 8% by mass or less with respect to the entire thermally conductive resin composition.

[0081] According to the second embodiment, composition (X) can be made to have improved fluidity.

[0082] In the third embodiment of the thermally conductive resin composition, in the first or second embodiment, the amount of (D) dispersant is 200 parts by mass or more and 1000 parts by mass or less per 100 parts by mass of (C) curing accelerator.

[0083] According to a third embodiment, composition (X) can further improve fluidity and storage stability, as well as the thermal conductivity of the cured resin product (Y).

[0084] In the fourth embodiment of the thermally conductive resin composition, in any one of the first to third embodiments, (D) the dispersant has an acid value greater than 0 mg KOH / g and an amine value greater than 0 mg KOH / g.

[0085] According to the fourth aspect, the composition (X) can further improve the thermal conductivity of the resin cured product (Y).

[0086] In the fifth embodiment of the thermally conductive resin composition, in the fourth embodiment, the dispersant (D) has an acid value of 10 mg KOH / g or more and 100 mg KOH / g or less, and an amine value of 10 mg KOH / g or more and 100 mg KOH / g or less.

[0087] According to the fifth aspect, composition (X) can further improve fluidity, storage stability, and thermal conductivity of the cured resin product (Y).

[0088] In the sixth embodiment of the thermally conductive resin composition, in any one of the first to fifth embodiments, (E) the filler comprises at least one of alumina and aluminum nitride.

[0089] According to the sixth aspect, the composition (X) can further improve the thermal conductivity of the resin cured product (Y).

[0090] In the seventh embodiment of the thermally conductive resin composition, in any one of the first to sixth embodiments, the proportion of (E) filler is 80% by mass or more of the total thermally conductive resin composition.

[0091] According to the seventh aspect, the composition (X) can further improve the thermal conductivity of the cured resin product (Y).

[0092] The eighth embodiment of the resin cured product is obtained by heating the thermally conductive resin composition of any one of the first to seventh embodiments.

[0093] According to the eighth aspect, the cured resin product (Y) has high thermal conductivity.

[0094] In the resin cured product of the ninth embodiment, the thermal conductivity is 4.5 W / m·K or higher, as in the eighth embodiment.

[0095] According to the ninth aspect, the cured resin product (Y) can have its thermal conductivity further improved.

Claims

1. A thermally conductive resin composition containing the following components (A) to (E): (A) an epoxy resin having a viscosity of 100 Pa·s or less at 25°C; (B) an acid anhydride; (C) a curing accelerator having a melting point of 150°C or higher or a softening point of 100°C or higher; (D) a dispersant having a weight-average molecular weight of 2000 or more in polystyrene terms as measured by gel permeation chromatography; (E) a filler having a thermal conductivity of 10 W / m·K or higher.

2. The thermal conductive resin composition according to claim 1, wherein the proportion of the epoxy resin (A) is 8% by mass or less with respect to the entire thermal conductive resin composition.

3. The thermally conductive resin composition according to claim 1, wherein the amount of the dispersant (D) is 200 parts by mass or more and 1000 parts by mass or less per 100 parts by mass of the curing accelerator (C).

4. The thermally conductive resin composition according to claim 1, wherein the dispersant (D) has an acid value greater than 0 mgKOH / g and an amine value greater than 0 mgKOH / g.

5. The thermally conductive resin composition according to claim 4, wherein the dispersant (D) has an acid value of 10 mg KOH / g or more and 100 mg KOH / g or less, and an amine value of 10 mg KOH / g or more and 100 mg KOH / g or less.

6. The thermally conductive resin composition according to claim 1, wherein the filler (E) comprises at least one of alumina and aluminum nitride.

7. The thermal conductive resin composition according to claim 1, wherein the proportion of the filler (E) is 80% by mass or more with respect to the entire thermal conductive resin composition.

8. A cured resin product obtained by heating the thermally conductive resin composition according to any one of claims 1 to 7.

9. The resin cured product according to claim 8, wherein the thermal conductivity is 4.5 W / m·K or higher.

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