Heat-curable resin composition and use thereof

Abstract

Provided is a heat-curable resin composition which comes to have a high glass transition temperature, excellent tracking resistance, and excellent long-term heat resistance. The heat-curable resin composition comprises (A) an aliphatic bismaleimide compound represented by formula (1) (wherein A is a C5-C12 divalent aliphatic hydrocarbon group and may be linear, branched, or cyclic), (B) a trisphenol alkane type epoxy resin, (C) a siloxane-bond-containing epoxy resin, (D) an epoxy resin hardener, (E) an inorganic filler, and (F) a hardening accelerator.

Description

Thermosetting resin composition and its use

[0001] This invention relates to a thermosetting resin composition suitable for use as a encapsulant for power semiconductors and to its use.

[0002] SiC power semiconductors are attracting considerable attention because they enable more efficient power utilization and smaller device size compared to conventional Si power semiconductors. In particular, in recent years, there has been progress in increasing the current and voltage of devices, and the junction temperature (Tj) of the chip can reach 200°C, so the encapsulating material also needs to have heat resistance that can withstand a 200°C environment.

[0003] Patent Document 1 discloses that a glass transition temperature (Tg) exceeding 200°C can be achieved by using a trisphenolmethane-type epoxy resin and a trisphenolmethane-type curing agent. Generally, methods for obtaining a thermosetting resin composition with a high glass transition temperature include increasing the crosslinking density and incorporating rigid structures such as aromatic rings. It is presumed that the invention described in Patent Document 1 achieves a glass transition temperature of 200°C because it satisfies the conditions of all of these methods.

[0004] Furthermore, with the miniaturization and thinning of devices and the increased performance of electronic equipment, circuit pitch widths and distances between lead terminals have also decreased, making it difficult to secure sufficient creepage distance for electrical insulation. Therefore, improved tracking resistance is required for encapsulating materials, and in particular, for automotive power device applications such as electric vehicles, achieving a comparative tracking index (CTI) of 600V is necessary.

[0005] Patent documents 2 and 3 disclose that excellent tracking resistance can be achieved by introducing an alicyclic structure into the epoxy resin structure. This is presumed to be due to the suppression of the formation of carbonized conductive paths, which are the cause of tracking, by reducing the proportion of aromatic rings in the epoxy resin structure. In other words, high heat resistance and tracking resistance are often in a trade-off relationship, and it is not easy to achieve a comparative tracking index of 600V in thermosetting resin compositions with high glass transition temperatures.

[0006] In recent years, maleimide resins have attracted attention as high-heat-resistant resins. For example, Patent Documents 4 and 5 disclose that the cured product exhibits a glass transition temperature exceeding 300°C, as measured by a thermomechanical analyzer. This is presumed to be due to the high crosslinking density unique to maleimide resins. Therefore, by using a fatty chain bismaleimide resin in which the maleimide groups at both ends are linked by fatty chains, it is expected that a high glass transition temperature in the maleimide portion and excellent tracking resistance in the fatty chain portion can be achieved simultaneously.

[0007] Japanese Patent Publication No. 2021-193158, Japanese Patent Publication No. 2005-213299, Japanese Patent Publication No. 2023-019588, Japanese Patent Publication No. 2015-193628, Japanese Patent Publication No. 2019-064926

[0008] However, fatty acid chains generally undergo thermal decomposition by oxygen in high-temperature environments due to the low bond energy of the carbon-carbon single bond sites, making them inferior to aromatic resins in terms of long-term heat resistance. Therefore, the present invention aims to provide a thermosetting resin composition that satisfies both a glass transition temperature of 200°C or higher and a comparative tracking index of 600V, and also exhibits excellent long-term heat resistance at 200°C.

[0009] The inventors of this invention conducted extensive research to achieve the above objectives and, as a result, discovered that the following thermosetting resin composition can achieve the above objectives, thus completing the present invention. That is, the present invention provides the following thermosetting resin composition.

[0010] [1] (A) an aliphatic bismaleimide compound represented by the following formula (1), (In formula (1), A is a divalent aliphatic hydrocarbon group having 5 to 12 carbon atoms, which may be linear, branched, or cyclic.) A thermosetting resin composition comprising: (B) a trisphenol alkane type epoxy resin; (C) a siloxane bond-containing epoxy resin; (D) an epoxy resin curing agent; (E) an inorganic filler; and (F) a curing accelerator, wherein component (A) is present in an amount of 10 to 30 parts by mass per 100 parts by mass of the total of components (A) to (D) in the thermosetting resin composition; component (B) is present in an amount of 30 to 70 parts by mass per 100 parts by mass of the total of components (A) to (D) in the thermosetting resin composition; and component (C) is present in an amount of 5 to 20 parts by mass per 100 parts by mass of the total of components (A) to (D) in the thermosetting resin composition. [1] A thermosetting resin composition in which component (D) is present in an amount such that the molar equivalent ratio of functional groups that react with epoxy groups in the epoxy resin curing agent to the total moles of epoxy groups in components (B) and (C) is 0.1 to 4.0. [2] The thermosetting resin composition according to [1], wherein component (B) is a trisphenolmethane type epoxy resin. [3] The thermosetting resin composition according to [1] or [2], wherein the epoxy equivalent of component (C) is 280 g / eq or more and 350 g / eq or less. [4] The thermosetting resin composition according to any one of [1] to [3], wherein component (D) is a phenolic curing agent. [5] A semiconductor encapsulant comprising the thermosetting resin composition according to any one of [1] to [4].

[0011] The cured product of the thermosetting resin composition of the present invention has a glass transition temperature (Tg) of 200°C or higher, a comparative tracking index (CTI) of 600V, and long-term heat resistance at 200°C. Therefore, the composition of the present invention is useful as a encapsulant for semiconductors, particularly for power semiconductors where high heat resistance and excellent tracking resistance are required.

[0012] Figure 1 is an example of a graph plotting the relationship between dimensional change and temperature for the results of measuring the dimensional change of a test specimen between 25°C and 300°C in the example, illustrating the method for determining the glass transition temperature.

[0013] The present invention will be described in detail below.

[0014] [(A) Aliphatic bismaleimide compound] Component (A) is an aliphatic bismaleimide compound represented by the following formula (1).

[0015] In formula (1) above, A is a divalent aliphatic hydrocarbon group having 5 to 12 carbon atoms, preferably 6 to 9 carbon atoms. The aliphatic hydrocarbon group represented by A may be linear, branched, or cyclic. In particular, the aliphatic hydrocarbon group represented by A is preferably linear or branched.

[0016] The aliphatic bismaleimide compound of component (A) has no particular limitations on its properties at room temperature (25°C ± 10°C) or its number-average molecular weight, but a number-average molecular weight of 200 to 10,000 is preferred, 200 to 5,000 is more preferred, and 200 to 1,000 is even more preferred. In this specification, the number-average molecular weight is the number-average molecular weight converted to a polystyrene standard by gel permeation chromatography (GPC) measurement using the following measurement conditions. [GPC Measurement Conditions] Developing solvent: Tetrahydrofuran (THF) Flow rate: 0.35 mL / min Detector: Differential refractive index detector (RI) Column: TSK Guardcolumn SuperH-L TSKgel SuperHZ4000 (4.6 mm I.D. × 15 cm × 1) TSKgel SuperHZ3000 (4.6 mm I.D. × 15 cm × 1) TSKgel SuperHZ2000 (4.6 mm I.D. × 15 cm × 2) (All manufactured by Tosoh Corporation) Column temperature: 40°C Sample injection volume: 5 μL (0.2 mass% THF solution)

[0017] Furthermore, if group A in the aliphatic bismaleimide compound of component (A) has fewer than 5 carbon atoms, the melting point of component (A) alone will be around 200°C, which overlaps with the temperature range during which the curing reaction proceeds when it is used as a resin composition. Therefore, from the viewpoint of obtaining a uniform cured product during molding, it is necessary that group A in the aliphatic bismaleimide compound of component (A) has 5 or more carbon atoms. Also, from the viewpoint of synthesis and acquisition of the diamine compound that serves as the raw material for component (A), the upper limit for the number of carbon atoms of group A is 12. Furthermore, the properties of the aliphatic bismaleimide compound of component (A) at room temperature are not particularly limited as described above. In addition, the melting point of the aliphatic bismaleimide compound of component (A) is preferably less than 160°C, and more preferably less than 140°C.

[0018] The aliphatic bismaleimide compound of component (A) may be used alone or in combination of two or more. In the composition of the present invention, the proportion of component (A) to 100 parts by mass of the total of components (A) to (D) is 10 to 30 parts by mass, preferably 20 to 30 parts by mass. When the amount ratio of component (A) is within this range, the composition is easy to handle during manufacturing. Furthermore, in the composition of the present invention, the total amount of components (A) to (D) is preferably 9 to 50% by mass, and more preferably 10 to 20% by mass.

[0019] [(B) Trisphenolalkane type epoxy resin] Component (B) is a trisphenolalkane type epoxy resin, for example, an epoxy resin represented by the following formula (2) is an example.

[0020] In the above equation (2), R 1 R is independently a hydrogen atom or a group selected from alkyl groups having 1 to 6 carbon atoms. 2 R is independently a hydrogen atom, or a group selected from an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms. 1 Examples include hydrogen atoms, methyl groups, ethyl groups, n-propyl groups, isopropyl groups, n-butyl groups, isobutyl groups, t-butyl groups, n-pentyl groups, neopentyl groups, n-hexyl groups, and cyclohexyl groups, with hydrogen atoms being preferred. 2The group is preferably a hydrogen atom, a methyl group, an ethyl group, or a phenyl group, and is particularly preferably a hydrogen atom. n is a number from 0 to 10, and is preferably a number from 0 to 3.

[0021] In the present invention, trisphenolmethane-type epoxy resins, such as trisphenolmethane epoxy compounds and trisphenolpropane epoxy compounds, are particularly preferred as component (B). The trisphenolalkane-type epoxy resin of component (B) may be used alone or in combination of two or more types. In the composition of the present invention, the ratio of component (B) to 100 parts by mass of the total of components (A) to (D) is 30 to 70 parts by mass, and preferably 40 to 60 parts by mass. This is because a cured product with excellent heat resistance can be easily obtained when the amount of component (B) is 30 parts by mass or more per 100 parts by mass of the total of components (A) to (D). However, if the amount of component (B) exceeds 70 parts by mass, the elastic modulus increases, which can cause cracking. Therefore, when the amount ratio of component (B) is within this range, a cured product with excellent moldability can be obtained.

[0022] [(C) Siloxane bond-containing epoxy resin] The siloxane bond-containing epoxy resin of component (C) can be a conventionally known silicone-modified epoxy resin. For example, a copolymer obtained by a hydrosilylation reaction between an alkenyl group-containing epoxy resin and a polysiloxane represented by any of the following formulas (3) to (5) can be used.

[0023]

[0024] In the above formula (3), R is independently a monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms. Specifically, alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, octyl group, nonyl group, decyl group, alkenyl groups such as vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, hexenyl group, cyclohexenyl group, octenyl group, aryl groups such as phenyl group, tolyl group, xylyl group, naphthyl group, aralkyl groups such as benzyl group, phenylethyl group, phenylpropyl group, etc. are included. Preferably, they are methyl group, ethyl group, and phenyl group.

[0025] R 3 is independently a hydrogen atom or a group represented by the above R. Specific examples include the same ones as those exemplified for the above R. R 4 is a group represented by the following formula (1').

[0026] In the above formula (1'), R and R 3 are the same groups as above, and n 4 is a number from 1 to 10, preferably 1 to 6.

[0027] In the above formula (3), n 1 is a number from 5 to 200, preferably 10 to 100. n 2 is a number from 0 to 2, preferably 0 or 1. n 3 is a number from 0 to 10, preferably 0 to 2. Also, n 1 n 2 and n 3 The bonding order of each siloxane unit enclosed by n 3 may be block or random. In the above formula (3), one or more, preferably 1 to 2 of R 2 are hydrogen atoms. Especially when n 3 =0, one or more, preferably 1 to 3 of R

[0028]

[0029] In the above formula (4), R is the same group as above. n 5n is a number between 1 and 10, preferably between 4 and 8. 6 n is 1 or 2, preferably 2. 5 +n 6 n is a number between 3 and 12, preferably between 3 and 8. 6 If n is 2, 5 and n 6 The bonding order of each siloxane unit enclosed in quotation marks may be in a block or random.

[0030]

[0031] In the above formula (5), R and R 3 R is the same group as above. r is a number from 0 to 3, preferably 1 to 2. 5 is a hydrogen atom, or one or more groups selected from C1-C10 alkyl groups and C2-C10 alkoxyalkyl groups, and the R 3 or R 5 One or more of them are hydrogen atoms.

[0032] Suitable polysiloxanes include dimethylpolysiloxane with dimethylhydrogensiloxy groups sealed at both ends of the molecular chain, and methylphenylpolysiloxane with dimethylhydrogensiloxy groups sealed at both ends of the molecular chain. For example, the following compounds are preferred. In formula (6) above, n is a number between 20 and 100, preferably between 20 and 80.

[0033] In formula (7) above, m is a number from 1 to 10, preferably from 1 to 5, and n is a number from 10 to 100, preferably from 20 to 60. The siloxane units enclosed by m and n may be linked in blocks or randomly.

[0034] Furthermore, alkenyl group-containing epoxy compounds can be obtained, for example, by epoxidizing an alkenyl group-containing phenol resin with epichlorohydrin, or by partially reacting a conventionally known epoxy compound with 2-allylphenol. These epoxy compounds can be represented, for example, by the following formulas (8) and (9).

[0035] In the above formula (8), R 1 R is a group represented by a glycidyloxy group or -OCH2CH(OH)CH2OR', 2 R is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 3 carbon atoms. 3 x is an aliphatic monovalent hydrocarbon group having an alkenyl group, with 3 to 15 carbon atoms, preferably 3 to 5 carbon atoms, where k is 1, k' is 0 to 3, k'' is 0 or 1, x is 1 to 10, and y is 1 to 3. The bonding of the repeating units enclosed by x and y may be in blocks or random.

[0036]

[0037] In the above formula (9), R 1 , R 2 k and k' are as described above, x' is a number from 1 to 30, and y' is a number from 1 to 3. The combination of repeating units enclosed by x' and y' may be a block or random.

[0038] Examples of epoxy compounds represented by the above formulas include the compounds of the following formulas (10) and (11).

[0039] In equation (10) above, the ranges of x and y are the same as those defined in equation (9) above. Note that the combination of repeating units enclosed by x and y may be in blocks or random.

[0040]

[0041] In the above formula (11), x' and y' are numbers that satisfy 1 ≤ x' ≤ 20 and 1 ≤ y' ≤ 3, preferably 1 ≤ x' ≤ 20 and y' = 1. The combination of repeating units enclosed by x' and y' may be in blocks or random.

[0042] Component (C) is a copolymer obtained from the hydrosilylation reaction of the above-mentioned alkenyl group-containing epoxy compound and polysiloxane. The hydrosilylation reaction can be carried out according to conventionally known methods. For example, it can be obtained by heating the reaction in the presence of a platinum-based catalyst such as chloroplatinic acid. The hydrosilyl reaction is particularly preferably carried out by heating at 60 to 120°C in an inert solvent such as benzene, toluene, or methyl isobutyl ketone. The mixing ratio of the epoxy compound to the siloxane should be such that the number of hydrosilyl groups in the siloxane per one alkenyl group in the epoxy compound is 1.0 or more, preferably 1.5 to 5.0. Component (C) may be used alone or in combination of two or more types.

[0043] The epoxy equivalent of component (C) is 280 g / eq or more and 350 g / eq or less, preferably 290 g / eq or more and 340 g / eq or less, and more preferably 300 g / eq or more and 330 g / eq or less. The amount of component (C) in the composition is 5 to 20 parts by mass, preferably 5 to 10 parts by mass, per 100 parts by mass of the total of components (A) to (D). If the content of component (C) is less than 5 parts by mass per 100 parts by mass of the total of components (A) to (D), the elastic modulus will increase, which can cause cracking. On the other hand, if the amount of component (C) exceeds 20 parts by mass per 100 parts by mass of the total of components (A) to (D), the viscosity of the resin composition will increase, which may cause molding defects such as insufficient resin filling into narrow areas.

[0044] [(D) Epoxy resin curing agent] The epoxy resin curing agent of component (D) is added for the purpose of curing the composition by reacting with the epoxy groups contained in components (B) and (C). The epoxy resin curing agent only needs to have a functional group that reacts with epoxy groups, and at least one selected from amine compounds, phenol compounds, acid anhydride compounds and active ester compounds is preferred.

[0045] Generally known amine compounds can be used. Aromatic amine compounds are preferred from the viewpoint of handling and moisture resistance reliability. Examples of preferred amine compounds include aromatic diaminodiphenylmethane compounds such as 3,3'-diethyl-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, and 3,3',5,5'-tetraethyl-4,4'-diaminodiphenylmethane; 2,4-diaminotoluene, 1,4-diaminobenzene, and 1,3-diaminobenzene are preferred, and aromatic diaminodiphenylmethane compounds such as 3,3'-diethyl-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, and 3,3',5,5'-tetraethyl-4,4'-diaminodiphenylmethane are more preferred. These may be used individually or in combination of two or more.

[0046] The above amine compound may be liquid or solid at room temperature (20-30°C). Liquid amine compounds can be added directly without issue, but solid amine compounds, if added directly, will increase the viscosity of the resin composition and significantly worsen workability. Therefore, it is preferable to melt-mix them with the epoxy resin beforehand, and it is preferable to melt-mix them at a temperature range of 70-150°C for 1-2 hours at a specific mixing ratio described later. If the mixing temperature is below 70°C, the amine compound may not be sufficiently miscible, and if the temperature exceeds 150°C, it may react with the epoxy resin and increase viscosity. Also, if the mixing time is less than 1 hour, the amine compound may not be sufficiently miscible and may lead to an increase in viscosity, and if it exceeds 2 hours, it may react with the epoxy resin and increase viscosity.

[0047] Generally known phenolic compounds can be used. Examples of phenolic compounds include phenol novolac resins, naphthalene ring-containing phenolic resins, aralkyl-type phenolic resins, triphenolalkane-type phenolic resins, biphenyl skeleton-containing aralkyl-type phenolic resins, biphenyl-type phenolic resins, alicyclic phenolic resins, heterocyclic phenolic resins, naphthalene ring-containing phenolic resins, resorcinol-type phenolic resins, allyl group-containing phenolic resins such as novolac-type allylphenolic resins, and bisphenol-type phenolic resins such as bisphenol A-type resins and bisphenol F-type resins. These may be used individually or in combination of two or more.

[0048] Generally known acid anhydride compounds can be used. Examples of acid anhydride compounds include 4-methylcyclohexane-1,2-dicarboxylic acid anhydride, 3,4-dimethyl-6-(2-methyl-1-propenyl)-1,2,3,6-tetrahydrophthalic anhydride, 1-isopropyl-4-methyl-bicyclo[2.2.2]octo-5-ene-2,3-dicarboxylic acid anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, methylhymicic anhydride, pyromellitic dianhydride, maleated allocimene, benzophenonetetracarboxylic acid dianhydride, 3,3',4,4'-biphenyltetrabisbenzophenonetetracarboxylic acid dianhydride, (3,4-dicarboxyphenyl) ether dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, and 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride. These may be used individually or in combination of two or more types.

[0049] The active ester compound can be one of the generally known types. Examples of active ester compounds include active ester compounds containing a dicyclopentadiene-type phenol resin structure, active ester compounds containing a phenol novolac structure, active ester compounds containing a naphthalene ring structure, active ester compounds containing an aralkyl-type phenol resin structure, active ester compounds containing a triphenolalkane-type phenol resin structure, active ester compounds containing a biphenyl skeleton-containing aralkyl-type phenol resin structure, active ester compounds containing a biphenyl-type phenol resin structure, active ester compounds containing an alicyclic phenol resin structure, active ester compounds containing a heterocyclic phenol resin structure, active ester compounds containing a naphthalene ring-containing phenol resin structure, active ester compounds containing a resorcinol-type phenol resin structure, active ester compounds containing an allyl group-containing phenol resin structure, active ester compounds containing a bisphenol A-type resin structure, and active ester compounds containing a bisphenol-type phenol resin structure such as bisphenol F-type resin. These may be used individually or in combination of two or more types.

[0050] The amount of epoxy resin curing agent in component (D) is such that the molar equivalent ratio of functional groups that react with epoxy groups in the epoxy resin curing agent to the total moles of epoxy groups in components (B) and (C) is 0.1 to 4.0, preferably 0.2 to 2.0, and particularly preferably 0.4 to 1.0. If the molar equivalent ratio is less than 0.1, unreacted epoxy groups may remain, potentially reducing adhesion, and if it exceeds 4.0, the moisture absorption rate of the cured product will increase, potentially causing cracks during reflow or temperature cycling. In this invention, equivalent refers to the molecular weight per functional group.

[0051] [(E) Inorganic Fillers] The inorganic fillers of component (E) are added to thermosetting resin compositions to improve resin strength and reduce thermal expansion. Examples of inorganic fillers include silicas (e.g., fused silica, crystalline silica, cristobalite, etc.), alumina, silicon nitride, aluminum nitride, boron nitride, titanium dioxide, glass fiber, magnesium oxide, etc. The average particle size and shape of these inorganic fillers can be selected according to the application.

[0052] In order to strengthen the bond between the resin and the inorganic filler, it is preferable to use an inorganic filler that has been pre-surface-treated with a coupling agent such as a silane coupling agent or a titanate coupling agent. Examples of such coupling agents include epoxysilanes such as γ-glycidoxypropyltrimexisilane, γ-glycidoxypropylmethyldiethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; aminosilanes such as N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, a reaction product of imidazole and γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and N-phenyl-γ-aminopropyltrimethoxysilane; and silane coupling agents such as γ-mercaptosilane and γ-episulfidoxypropyltrimethoxysilane. There are no particular restrictions on the amount of coupling agent used for surface treatment or the surface treatment method.

[0053] The amount of inorganic filler in component (E) is preferably 100 to 1,000 parts by mass, and more preferably 400 to 900 parts by mass, relative to 100 parts by mass of components (A) to (D). When the ratio of inorganic filler to 100 parts by mass of components (A) to (D) is within this range, the composition has excellent handling properties during manufacturing.

[0054] [(F) Curing accelerator] The curing accelerator of component (F) is a component added to promote the curing of the aliphatic bismaleimide compound (A) above, and generally known ones can be used, such as imidazole-based curing accelerators, organophosphorus-based curing accelerators, tertiary amine-based curing accelerators, and organic peroxide-based curing accelerators. Examples of imidazole-based curing accelerators include 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, and 2-phenyl-4-methylimidazole. Examples of organophosphorus curing accelerators include phosphines such as triphenylphosphine, tributylphosphine, tri(p-methylphenyl)phosphine, and tri(nonylphenyl)phosphine; phosphine-borane complexes such as triphenylphosphine-triphenylborane; phosphonium borate salts such as tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra-p-tolylborate, p-tolyltriphenylphosphonium tetra-p-tolylborate, and tri-tert-butylphosphonium tetraphenylborate; and bis(tetrabutylphosphonium)dihydrogenpyromellitate. Examples of tertiary amine curing accelerators include tertiary amine compounds such as triethylamine, benzyldimethylamine, α-methylbenzyldimethylamine, and 1,8-diazabicyclo[5.4.0]undecene-7; and salts of tertiary amine compounds such as 1,8-diazabicyclo[5.4.0]undecene-7. Examples of organic peroxide-based curing accelerators include dicumyl peroxide, t-butyl peroxybenzoate, t-amyl peroxybenzoate, dibenzoyl peroxide, diuraloyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 1,1-di(t-butylperoxy)cyclohexane, di-t-butyl peroxide, and dibenzoyl peroxide. The curing accelerator of component (F) may be used alone or in combination of two or more types.

[0055] (F) The amount of curing accelerator added is preferably 0.01 to 10 parts by mass, and more preferably 1 to 5 parts by mass, per 100 parts by mass of the total of components (A) to (D) above, in order to promote curing. When the amount of component (F) added is within this range per 100 parts by mass of the total of components (A) to (D) above, there is no risk that the curing speed during molding will be too slow or too fast.

[0056] [(G) Other Additives] In addition to the components (A) to (F) above, the thermosetting resin composition of the present invention may contain other additives as needed, to the extent that they do not impair the purpose and effects of the present invention. Examples of such additives include flame retardants, ion trapping agents, antioxidants, adhesion promoters, silane coupling agents, mold release agents, stress reduction agents, and colorants.

[0057] Flame retardants are added for the purpose of imparting flame retardancy. There are no particular limitations on the flame retardants, and all known ones can be used. For example, phosphazene compounds, silicone compounds, zinc molybdate-supported talc, zinc molybdate-supported zinc oxide, aluminum hydroxide, boehmite, magnesium hydroxide, and molybdenum oxide can be used.

[0058] Ion trapping agents are added to resin compositions to capture ionic impurities and prevent thermal and hygroscopic degradation. There are no particular limitations on the ion trapping agent; all known agents can be used, including hydrotalcites, bismuth hydroxide compounds, and rare earth oxides.

[0059] There are no particular restrictions on the antioxidant, but examples include n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)acetate, neododecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, dodecyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, ethyl 2-α-(4-hydroxy-3,5-di-t-butylphenyl) isobutyrate, octadecyl-α-(4-hydroxy-3,5-di-t-butylphenyl) isobutyrate, octadecyl-α-(4-hydroxy-3,5-di-t-butyl-4-hydroxyphenyl) propionate, 2-(n-octylthio)ethyl-3,5-di-t-butyl-4-hydroxyphenyl acetate, 2-(n-octadecylthio)ethyl-3, 5-di-t-butyl-4-hydroxyphenyl acetate, 2-(n-octadecylthio)ethyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2-(2-stearoyloxyethylthio)ethyl-7-(3-methyl-5-t-butyl-4-hydroxyphenyl)heptanoate, 2-hydroxyethyl-7-(3-methyl-5-t-butyl-4-hydroxyphenyl)propionate, pentae Phenolic antioxidants such as lysritol tetrakiss [3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]; sulfur-based antioxidants such as dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, ditridecyl-3,3'-thiodipropionate, and pentaerythrityl tetrakiss (3-laurylthiopropionate);Examples of phosphorus-based antioxidants include tridecyl phosphite, triphenyl phosphite, tris(2,4-di-t-butylphenyl) phosphite, 2-ethylhexyl diphenyl phosphite, diphenyl tridecyl phosphite, 2,2-methylenebis(4,6-di-t-butylphenyl)octyl phosphite, distearyl pentaerythritol diphosphite, bis(2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, and 2-[[2,4,8,10-tetrakis(1,1-dimethylethyl)dibenzo[d,f][1,3,2]dioxaphosfepin-6-yl]oxy]-N,N-bis[2-[[2,4,8,10-tetrakis(1,1-dimethylethyl)dibenzo[d,f][1,3,2]dioxaphosfepin-6-yl]oxy]-ethyl]ethanamine.

[0060] The adhesion-imparting agent is not particularly limited as long as it is a known adhesion-imparting agent that achieves the effects of the present invention, and may be included as needed to impart adhesion or tackiness (pressure-sensitive adhesion). Examples of adhesion-imparting agents include urethane resins, phenolic resins, terpene resins, and silane coupling agents. Among these, silane coupling agents are preferred for imparting adhesion.

[0061] There are no particular restrictions on the silane coupling agent, but examples include silane coupling agents such as n-propyltrimethoxysilane, n-propyltriethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, 2-[methoxy(polyethyleneoxy)propyl]-trimethoxysilane, methoxytri(ethyleneoxy)propyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, and 3-isocyanatopropyltrimethoxysilane.

[0062] Release agents are added to improve the release properties from the mold. Examples of known release agents that can be used include carnauba wax, rice wax, candelilla wax, polyethylene, polyethylene oxide, polypropylene, montanic acid, montan wax (an ester compound of montanic acid with saturated alcohol, 2-(2-hydroxyethylamino)ethanol, ethylene glycol, glycerin, etc.), stearic acid, stearic acid esters, stearic acid amides, and others.

[0063] The amount of other additives varies depending on the purpose of the composition, but is usually 5% or less of the total composition. If additives are used, the amount should be 0.05% or more of the total composition.

[0064] [Method for Producing the Composition] The thermosetting resin composition of the present invention can be produced by the following method. For example, (A) an aliphatic bismaleimide compound, (B) a trisphenol alkane type epoxy resin, (C) a siloxane bond-containing epoxy resin, (D) an epoxy resin curing agent, (E) an inorganic filler, and (F) a curing accelerator are mixed simultaneously or separately for 5 minutes to 5 hours while being heated at 80 to 120°C as needed, and then stirred, dissolved and / or dispersed to obtain a mixture of components (A) to (F). Preferably, a curing accelerator (F) may be added to the mixture of components (A) to (E), and then stirred, dissolved and / or dispersed to obtain a mixture of components (A) to (F). Depending on the intended use, (G) other additives such as flame retardants, ion trapping agents, antioxidants, adhesion promoters, silane coupling agents, mold release agents, stress reduction agents, and colorants may be added to the mixture of components (A) to (F) and mixed. Each component may be used individually or in combination of two or more types.

[0065] The method for producing the composition is not particularly limited to the apparatus used for mixing, stirring, and dispersion. Specifically, for example, a mixing machine equipped with stirring and heating devices, a two-roll mill, a three-roll mill, a ball mill, a sinker mixer, a planetary mixer, or a mass colloider can be used, and these devices may be used in appropriate combinations.

[0066] [Applications] The thermosetting resin composition of the present invention has excellent tracking resistance (CTI ≥ 600V) and high heat resistance with a glass transition temperature (Tg) of 200°C, making it suitable for use as an adhesive and semiconductor encapsulant. When used as a semiconductor encapsulant, it is preferable to blend each component in a predetermined composition ratio as described above, thoroughly and uniformly mix them using a mixer or the like, then melt and mix them using a hot roll, kneader, extruder or the like, then cool and solidify, and finally pulverize to an appropriate size. Common molding methods using semiconductor encapsulants include transfer molding and compression molding. In the transfer molding method, a transfer molding machine is used, and the molding pressure is 5 to 20 N / mm. 2 The molding process is carried out at a molding temperature of 120 to 190°C for 30 to 500 seconds, preferably at a molding temperature of 150 to 185°C for 30 to 180 seconds. In the compression molding method, a compression molding machine is used, and the molding temperature is 120 to 190°C for 30 to 600 seconds, preferably at a molding temperature of 130 to 160°C for 120 to 300 seconds. Furthermore, in any of the molding methods, post-curing may be carried out at 150 to 230°C for 0.5 to 20 hours.

[0067] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following, the number-average molecular weight (Mn) is measured by gel permeation chromatography (GPC) using polystyrene as the reference under the following measurement conditions. In the following formulas, Me represents a methyl group. [GPC Measurement Conditions] Developing solvent: Tetrahydrofuran (THF) Flow rate: 0.35 mL / min Detector: Differential refractive index detector (RI) Column: TSK Guardcolumn SuperH-L TSKgel SuperHZ4000 (4.6 mm I.D. × 15 cm × 1) TSKgel SuperHZ3000 (4.6 mm I.D. × 15 cm × 1) TSKgel SuperHZ2000 (4.6 mm I.D. × 15 cm × 2) (All manufactured by Tosoh Corporation) Column temperature: 40°C Sample injection volume: 5 μL (0.2 mass% THF solution)

[0068] (A) Aliphatic bismaleimide compounds [Synthesis Example 1] In a 2 L four-necked glass flask equipped with a stirrer, Dean-Stark tube, cooling condenser, and thermometer, 158.35 g (1.0 mol) of trimethylhexanediamine (2,2,4-,2,4,4- mixture), 205.94 g (2.1 mol) of maleic anhydride, 600 g of toluene, and 257 g of N-methyl-2-pyrrolidone were added to prepare a reaction solution, which was stirred at 80°C for 3 hours to synthesize amical. Then, 96.10 g of methanesulfonic acid was added to the reaction solution, and the temperature was raised to 110°C. The mixture was stirred for 16 hours while removing the by-product water, and the reaction solution was washed five times with 300 g of deionized water. Then, precipitation was performed using heptane, and filtration was performed to obtain 237.81 g (yield 75%) of the target product ((A-1), Mn318, melting point 88°C) as a white solid at room temperature.

[0069] [Synthesis Example 2] In a 2 L four-necked glass flask equipped with a stirrer, Dean-Stark tube, cooling condenser, and thermometer, 200.38 g (1.0 mol) of 1,12-dodecanediamine, 205.97 g (2.1 mol) of maleic anhydride, 600 g of toluene, and 277 g of N-methyl-2-pyrrolidone were added to prepare a reaction solution, which was stirred at 80°C for 3 hours to synthesize amical. Subsequently, 96.10 g of methanesulfonic acid was added to the reaction solution, and the temperature was raised to 110°C. The mixture was stirred for 16 hours while removing the by-product water by distillation, and then the reaction solution was washed five times with 500 g of deionized water. After that, precipitation was performed using heptane, and filtration yielded 267.7 g (yield 74%) of the target product ((A-2), Mn441, melting point 116°C) as a brown solid at room temperature.

[0070] (B) Trisphenolalkane type epoxy resin (B-1) Trisphenolmethane type epoxy resin (Product name: EPPN-502H, manufactured by Nippon Kayaku Co., Ltd., softening point 72°C, epoxy equivalent 168 g / eq)

[0071] (C) Siloxane bond-containing epoxy resin (C-1) Siloxane bond-containing epoxy resin [Synthesis Example 3] 400 g of toluene and 10 g of allyl group-containing epoxy resin (epoxy equivalent 192 g / eq) represented by the following formula (12) were placed in a 2 L four-necked flask equipped with a reflux condenser, thermometer, stirrer, and dropping funnel, and azeotropic dehydration was carried out under a nitrogen atmosphere for 2 hours. Then, the system was cooled to 80°C, 1.00 g of platinum chloride catalyst was added, and a solution of 48.5 g of hydrogen organopolysiloxane represented by the following formula (13) dissolved in 194.1 g of toluene was added dropwise over 2 hours. The system was stirred for 6 hours while maintaining the temperature at 90-100°C, and after maturation, it was cooled to room temperature. Then, the solvent was removed under reduced pressure to obtain 56.2 g of the target silicone-modified epoxy resin (compound A, epoxy equivalent 308 g / eq). (C'-1) Epoxy resin for comparative example: Dicyclopentadiene type epoxy resin (product name: HP-7200, manufactured by DIC Corporation, softening point 57°C, epoxy equivalent 259 g / eq)

[0072] (D) Epoxy resin curing agent (D-1) Trisphenolmethane type phenol resin (product name: MEH-7500H, manufactured by Meiwa Chemicals Co., Ltd., softening point 119°C, hydroxyl group equivalent 97) (D-2) Novolac type phenol resin (product name: TD-2131, manufactured by DIC Corporation, softening point 78°C, hydroxyl group equivalent 110)

[0073] (E) Inorganic filler (E-1) Silica dry-surface-treated with 0.3 parts by mass of N-phenyl-γ-aminopropyltrimethoxysilane (product name: KBM-573, manufactured by Shin-Etsu Chemical Co., Ltd.) per 100 parts by mass of molten spherical silica (product name: FB-5604FC, manufactured by Denka Co., Ltd.) with an average particle size of 27 μm and a maximum particle size of 55 μm.

[0074] (F) Curing accelerator (F-1) Salt of 2-phenylimidazole and trimellitic anhydride (product name: 2PZ-TMA, manufactured by Junsei Chemical Co., Ltd.) (F-2) Dicumyl peroxide (product name: Permil D, manufactured by NOF Corporation)

[0075] (G) Other additives (G-1) Silane coupling agent: N-phenyl-3-aminopropyltrimethoxysilane (product name "KBM-573", manufactured by Shin-Etsu Chemical Co., Ltd.) (G-2) Flame retardant: Boehmite (product name: Boehmite C20, manufactured by Daimyo Chemical Industry Co., Ltd., average particle size 1.9 μm) (G-3) Release agent: Carnauba wax (product name: TOWAX-131, manufactured by Toa Chemical Co., Ltd.) (G-4) Coloring agent: Black pigment (product name: Mitsubishi Carbon Black 3230MJ, manufactured by Mitsubishi Chemical Corporation)

[0076] The above components were mixed in the amounts (parts by mass) shown in Table 1 to obtain a thermosetting resin composition. The "EP / OH ratio" shown in Table 1 refers to the ratio of the molar equivalent (active hydrogen equivalent) of the reactive functional group (phenolic hydroxyl group) of the epoxy resin curing agent in component (D) to the molar equivalent of the epoxy group contained in the epoxy resin of component (B) and component (C).

[0077] [Spiral Flow Measurement] Using a mold conforming to EMMI standards, the molding temperature was 175°C and the molding pressure was 6.9 N / mm. 2 The measurement was taken under conditions of a molding time of 300 seconds.

[0078] [Measurement of Glass Transition Temperature (Tg)] Each composition was transfer molded at 175°C for 180 seconds under a molding pressure of 6.9 MPa, and then post-cured at 230°C for 4 hours to obtain test specimens measuring 5 mm × 5 mm × 15 mm thick. These test specimens were placed in a thermomechanical analyzer TMA8311 (manufactured by Rigaku Corporation). The heating program was set to a heating rate of 5°C / min, and a constant load of 19.6 mN was applied. The dimensional change of the test specimens was then measured between 25°C and 300°C. The relationship between this dimensional change and temperature was plotted on a graph. From the graphs of dimensional change and temperature obtained in this way, the glass transition temperatures in the examples and comparative examples were determined using the glass transition temperature determination method described below, and the measurement results of the glass transition temperatures of each cured product are shown in Table 1.

[0079] [Determination of Glass Transition Temperature (Tg)] Figure 1 is a graph showing the method for determining the glass transition temperature. In Figure 1, two arbitrary temperature points where a tangent to the dimensional change-temperature curve is obtained below the inflection point temperature are designated as T1 and T2, and two arbitrary temperature points where a similar tangent is obtained above the inflection point temperature are designated as T1' and T2'. The glass transition temperature (Tg) is defined as the intersection of a straight line connecting points (T1, D1) and (T2, D2), where the dimensional changes at T1' and T2' are D1' and D2', respectively, and a straight line connecting points (T1', D1') and (T2', D2').

[0080] [Tracking Resistance (CTI) Measurement] Each composition was transfer molded at 175°C for 180 seconds under a molding pressure of 6.9 MPa, and then post-cured at 230°C for 4 hours to obtain a 3 mm thick, 50 mm diameter hardened disc. Using these hardened discs, tracking resistance was measured according to the method of JIS C 2134:2021 (IEC 60112). As the tracking resistance voltage, in an evaluation with n=5 samples, the maximum voltage at which all hardened discs did not break down even when 50 or more drops of 0.1% aqueous solution of ammonium chloride were added was measured. The upper limit was set at 600V.

[0081] Each composition was transfer-molded at 175°C for 180 seconds under a molding pressure of 6.9 MPa, and then post-cured at 230°C for 4 hours to obtain test specimens measuring 10 mm × 4 mm × 100 mm. These test specimens were then placed in a 200°C dryer for 1,000 hours, and their weights were measured before and after the drying period. The percentage change in weight during storage at 200°C was then calculated.

[0082]

[0083] The results in Table 1 clearly show that Examples 1-4, which contain aliphatic bismaleimide resin, have superior glass transition temperature, tracking resistance, and long-term heat resistance up to 200°C compared to Comparative Examples 1-4.

Claims

1. (A) Aliphatic bismaleimide compounds represented by the following formula (1), (In formula (1), A is a divalent aliphatic hydrocarbon group having 5 to 12 carbon atoms, which may be linear, branched, or cyclic.) A thermosetting resin composition comprising: (B) a trisphenol alkane type epoxy resin; (C) a siloxane bond-containing epoxy resin; (D) an epoxy resin curing agent; (E) an inorganic filler; and (F) a curing accelerator, wherein component (A) is present in an amount of 10 to 30 parts by mass per 100 parts by mass of the total of components (A) to (D) in the thermosetting resin composition; component (B) is present in an amount of 30 to 70 parts by mass per 100 parts by mass of the total of components (A) to (D) in the thermosetting resin composition; and component (C) is present in an amount of 5 to 20 parts by mass per 100 parts by mass of the total of components (A) to (D) in the thermosetting resin composition. A thermosetting resin composition in which component (D) is present in an amount such that the molar equivalent ratio of functional groups that react with epoxy groups in the epoxy resin curing agent to the total moles of epoxy groups in components (B) and (C) is 0.1 to 4.

0.

2. The thermosetting resin composition according to claim 1, wherein component (B) is a trisphenolmethane type epoxy resin.

3. The thermosetting resin composition according to claim 1, wherein the epoxy equivalent of component (C) is 280 g / eq or more and 350 g / eq or less.

4. The thermosetting resin composition according to claim 1, wherein component (D) is a phenolic curing agent.

5. A semiconductor encapsulant comprising the thermosetting resin composition according to any one of claims 1 to 4.

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