Resin composition

Abstract

The purpose of the present invention is to provide a resin composition capable of exhibiting long-term reliability even at high temperatures after curing.　A resin composition according to the present disclosure is characterized by comprising an epoxy compound (A), an acid anhydride (B), a silica filler (C), a curing accelerator (D), and a flame retardant (E) that contains a phosphorus-based component, said resin composition having a glass transition temperature (Tg) of at least 160ºC and being liquid at room temperature. Moreover, the thickness change rate after said resin composition has been cured into a shape having a thickness of 2 mm, a width of 3 cm, and a length of 5 cm and heated under the conditions of 200ºC and 1,000 hours is preferably at most 5%.

Description

resin composition

[0001] This disclosure relates to a resin composition. This application claims priority to Japanese Patent Application No. 2025-004151, filed in Japan on January 10, 2025, which is incorporated herein by reference.

[0002] Conventionally, halogen-based flame retardants, such as brominated flame retardants, have been used to impart heat resistance and flame retardancy to resin compositions for semiconductor encapsulation (for example, Patent Document 1).

[0003] Japanese Patent Publication No. 2004-339292

[0004] However, in recent years, as electronic devices for automotive and other applications have become more high-performance, they need to handle higher currents. Therefore, conventional resins using halogen-based flame retardants have insufficient heat resistance and flame retardancy under higher temperature conditions. Furthermore, higher reliability is required to prevent serious accidents in the event of overcurrent or short circuits.

[0005] Therefore, the object of this disclosure is to provide a resin composition that can maintain reliability over a long period of time even at high temperatures after curing.

[0006] As a result of diligent efforts to solve the above problems, the Discloser has found that a resin composition containing an epoxy compound (A), an acid anhydride (B), a silica filler (C), a curing accelerator (D), and a flame retardant (E) containing a phosphorus-based component, having a glass transition temperature (Tg) of 160°C or higher and being liquid at room temperature, can exhibit long-term reliability even at high temperatures after curing. This disclosure relates to a product completed based on these findings.

[0007] In other words, the present disclosure provides a resin composition comprising an epoxy compound (A), an acid anhydride (B), a silica filler (C), a curing accelerator (D), and a flame retardant (E) containing a phosphorus-based component, having a glass transition temperature (Tg) of 160°C or higher and being liquid at room temperature.

[0008] The above resin composition preferably hardens into a shape with a thickness of 2 mm, a width of 3 cm, and a length of 5 cm, and the rate of change in thickness after heating at 200°C for 1000 hours is 5% or less.

[0009] The above resin composition preferably has flame retardancy of V-1 or higher in a vertical combustion test in accordance with the UL94 standard after curing.

[0010] The above resin composition preferably hardens into a shape with a thickness of 2 mm, a width of 3 cm, and a length of 5 cm, and has a weight retention rate of 85% or more after heating at 200°C for 1000 hours.

[0011] The epoxy compound (A) described above preferably includes an alicyclic epoxy compound.

[0012] Preferably, the epoxy compound (A) further includes an aromatic glycidyl ether type epoxy resin and / or an aromatic glycidylamine type epoxy resin.

[0013] Preferably, the aromatic glycidyl ether type epoxy resin includes a bisphenol A type epoxy resin, and the glycidylamine type epoxy resin includes a compound having a diglycidylaniline skeleton.

[0014] It is preferable that the compound having the diglycidylaniline skeleton described above includes N,N-bis(2,3-epoxypropyl)-o-toluidine.

[0015] Preferably, the above resin composition further contains an inorganic flame retardant.

[0016] The resin composition of this disclosure can maintain reliability over a long period of time, even at high temperatures, after curing.

[0017] [Resin Composition] A resin composition according to one embodiment of the present disclosure comprises an epoxy compound (A), an acid anhydride (B), a silica filler (C), a curing accelerator (D), and a flame retardant (E) containing a phosphorus-based component, has a glass transition temperature (Tg) of 160°C or higher, and is liquid at room temperature. Hereafter, the above resin composition may be referred to as "the resin composition of the present disclosure" in this specification.

[0018] Furthermore, in this disclosure, "liquid at room temperature" means that the substance is fluid at 25°C, and "solid at room temperature" means that the substance is solid at 25°C and does not exhibit fluidity.

[0019] Furthermore, in this disclosure, compounds having two or more epoxy groups may be simply referred to as "epoxy compounds." Also, glycidyl groups may be simply referred to as "epoxy groups."

[0020] The glass transition temperature (Tg) of the resin composition disclosed herein is 160°C or higher, preferably 170°C or higher, and more preferably 175°C or higher. A Tg of 160°C or higher allows the composition to exhibit heat resistance. While there is no particular upper limit, a Tg of 300°C or lower is preferable.

[0021] The resin composition of this disclosure preferably has a coefficient of linear expansion (α1) of 30 ppm / °C or less, more preferably 25 ppm / °C or less, and even more preferably 20 ppm / °C or less, measured at a heating rate of 5°C / min when cured, from 60 to 80°C. By keeping α1 at 30 ppm / °C or less, the coefficient of linear expansion is kept low, which suppresses the peeling of the cured product from the adherend. Furthermore, there is no particular lower limit, but it is preferably 1 ppm / °C or more.

[0022] The resin composition of this disclosure preferably has a coefficient of linear expansion (α2) of 110 ppm / °C or less, more preferably 100 ppm / °C or less, even more preferably 90 ppm / °C or less, and particularly preferably 70 ppm / °C or less, as measured under a heating condition of 5°C / min when cured, from 240 to 260°C. By keeping α2 at 110 ppm / °C or less, the coefficient of linear expansion is kept low even under high-temperature conditions, thereby suppressing the peeling of the cured product from the adherend. Furthermore, there is no particular lower limit, but it is preferably 10 ppm / °C or more.

[0023] The resin composition of this disclosure is cured into a shape with a thickness of 2 mm, a width of 3 cm, and a length of 5 cm. Preferably, the rate of change in thickness after heating at 200°C for 1000 hours is 5% or less, more preferably 4% or less, and even more preferably 3% or less. A rate of change in thickness of 5% or less results in a small change in thickness before and after heating, allowing for long-term reliability. Furthermore, there is no particular lower limit, and it may be 0%.

[0024] Furthermore, the resin composition of this disclosure is preferably cured into a shape with a thickness of 2 mm, a width of 3 cm, and a length of 5 cm, and has a weight retention rate of 85% or more after heating at 200°C for 1000 hours, more preferably 90% or more, and even more preferably 95% or more. A weight retention rate of 85% or more results in minimal change in composition even at high temperatures, making it easier to demonstrate reliability. There is no particular upper limit, but it may be 100%.

[0025] Preferably, after curing, the resin composition of this disclosure has a flame retardancy rating of V-1 or higher in a vertical combustion test in accordance with the UL94 standard, and more preferably, a flame retardancy rating of V-0 or higher. A rating of V-1 or higher in the above flammability test ensures sufficient flame retardancy and makes it easier to demonstrate reliability.

[0026] The resin composition of this disclosure contains components (A) to (E) above and is therefore liquid at room temperature. The viscosity measured at room temperature at a rotation speed of 0.01 to 100 rpm is preferably 1000 Pa·s or less, more preferably 900 Pa·s or less, and even more preferably 800 Pa·s or less. The viscosity measured under the above conditions of 1000 Pa·s or less provides excellent handling properties. There is no particular lower limit, but it is preferably 1 Pa·s or more.

[0027] <Epoxy Compound (A)> The resin composition of this disclosure contains epoxy compound (A). The epoxy compound (A) is a compound having two or more epoxy groups in its molecule, and can be arbitrarily selected from known or conventional epoxy compounds. Furthermore, in this disclosure, only one epoxy compound (A) may be used, or two or more may be used.

[0028] Examples of the epoxy compound (A) mentioned above include aromatic epoxy compounds, aliphatic epoxy compounds, alicyclic epoxy compounds, heterocyclic epoxy compounds, and siloxane derivatives having two or more epoxy groups in the molecule.

[0029] Examples of the above aromatic epoxy compounds include aromatic glycidyl ether epoxy resins, aromatic glycidylamine type epoxy resins, and aromatic glycidyl ester type epoxy resins. Examples of the above aromatic glycidyl ether epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, biphenol type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, novolac type epoxy resins such as cresol novolac type epoxy resin of bisphenol A, naphthalene type epoxy resins, and epoxy resins obtained from trisphenolmethane. Examples of the above aromatic glycidylamine type epoxy resins include tetraglycidyldiaminodiphenylmethane, triglycidyl-p-aminophenol, triglycidylaminocresol, diglycidylaniline, N,N-diglycidyl-4-glycidyloxyaniline, and compounds having the skeletons of the above components. Examples of the above-mentioned aromatic glycidyl ester type epoxy resins include diglycidyl esters of aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, tetrahydrophthalic acid, and hexahydrophthalic acid, as well as alkene oxides such as vinylcyclohexene dioxide and triglycidyl isocyanurates.

[0030] The above-mentioned bisphenol A type epoxy resin is a compound having one or more bisphenol A skeletons and two or more epoxy groups in its molecule.

[0031] The epoxy equivalent of the bisphenol A type epoxy resin is not particularly limited, but is preferably 2000 (g / eq) or less, and more preferably 1000 or less. By setting the epoxy equivalent of the bisphenol A type epoxy resin to 2000 or less, the viscosity of the resin composition is prevented from becoming too high, and handling tends to improve. The lower limit of the epoxy equivalent is not particularly limited, but is preferably 30 or more, and more preferably 50 or more.

[0032] The weight-average molecular weight (Mw) of the above-mentioned bisphenol A type epoxy resin, on a standard polystyrene basis, is not particularly limited, but is preferably 10,000 or less, and more preferably 8,000 or less. By setting the weight-average molecular weight of the bisphenol A type epoxy resin to 10,000 or less, the viscosity of the resin composition is prevented from becoming too high, and handling tends to improve. The lower limit of the above-mentioned weight-average molecular weight is not particularly limited, but is preferably 60 or more, and more preferably 100 or more. The weight-average molecular weight can be measured, for example, by gel permeation chromatography (GPC).

[0033] As the bisphenol A type epoxy resin mentioned above, commercially available products such as "YD-128" (manufactured by Nippon Steel Chemical & Material Co., Ltd.) can also be used.

[0034] The above-mentioned aromatic glycidylamine-type epoxy resin is preferably a compound having a diglycidylaniline skeleton, specifically including N,N-bis(2,3-epoxypropyl)-o-toluidine, N,N-bis(2,3-epoxypropyl)-m-toluidine, N,N-bis(2,3-epoxypropyl)-p-toluidine, diglycidyl-xylidine, diglycidyl-mesidine, diglycidyl-anisidine, diglycidyl-phenoxyaniline, or diglycidyl-naphthylamine. In particular, to achieve low viscosity while maintaining the glass transition temperature (Tg) of the resin composition of this disclosure, it is especially preferable to include N,N-bis(2,3-epoxypropyl)-o-toluidine as the compound having the diglycidylaniline skeleton.

[0035] The above alicyclic epoxy compound is a compound having one or more alicyclic rings (aliphatic hydrocarbon rings) and two or more epoxy groups in the molecule, excluding the compounds corresponding to the above siloxane derivatives having two or more epoxy groups in the molecule. Examples of the above alicyclic epoxy compound include (i) a compound having at least one, preferably two or more alicyclic epoxy groups (epoxy groups composed of two adjacent carbon atoms and an oxygen atom constituting an alicyclic ring) in the molecule; (ii) a compound having an epoxy group directly bonded to an alicyclic ring by a single bond; (iii) a compound having an alicyclic ring and a glycidyl group, and the like.

[0036] The alicyclic epoxy groups of the above compound (i) having at least two alicyclic epoxy groups in the molecule are not particularly limited. Among them, from the viewpoint of curability, a cyclohexene oxide group (an epoxy group composed of two adjacent carbon atoms and an oxygen atom constituting a cyclohexane ring) is preferable. In particular, as the compound (i) having at least two alicyclic epoxy groups in the molecule, from the viewpoint of the heat resistance of the cured product, a compound having two or more cyclohexene oxide groups in the molecule is preferable, and more preferably a compound represented by the following formula (I).

[0037]

[0038] In the above formula (I), Z represents a single bond or a linking group (a divalent group having one or more atoms). Examples of the above linking group include a divalent hydrocarbon group, an alkenylene group in which part or all of the carbon-carbon double bond is epoxidized, a carbonyl group, an ether bond, an ester bond, a carbonate group, an amide group, and a group in which a plurality of these are linked. In addition, a substituent such as an alkyl group may be bonded to one or more of the carbon atoms constituting the cyclohexane ring in the formula (I).

[0039] Examples of the compound in which Z in the above formula (I) is a single bond include 3,4,3',4'-diepoxy bicyclohexane and the like.

[0040] Examples of the divalent hydrocarbon group include linear or branched alkylene groups having 1 to 18 carbon atoms, divalent alicyclic hydrocarbon groups, etc. Examples of the linear or branched alkylene group having 1 to 18 carbon atoms include a methylene group, a methylmethylene group, a dimethylmethylene group, an ethylene group, a propylene group, a trimethylene group, etc. Examples of the divalent alicyclic hydrocarbon group include divalent cycloalkylene groups such as a 1,2-cyclopentylene group, a 1,3-cyclopentylene group, a cyclopentylidene group, a 1,2-cyclohexylene group, a 1,3-cyclohexylene group, a 1,4-cyclohexylene group, a cyclohexylidene group, etc.

[0041] Examples of the alkenylene group in the alkenylene group in which some or all of the carbon-carbon double bonds are epoxidized (sometimes referred to as an "epoxidized alkenylene group") include linear or branched alkenylene groups having 2 to 8 carbon atoms such as a vinylene group, a propenylene group, a 1-butenylene group, a 2-butenylene group, a butadienylene group, a pentenylene group, a hexenylene group, a heptenylene group, an octenylene group, etc. In particular, as the epoxidized alkenylene group, an alkenylene group in which all of the carbon-carbon double bonds are epoxidized is preferable, and more preferably an alkenylene group having 2 to 4 carbon atoms in which all of the carbon-carbon double bonds are epoxidized.

[0042] In particular, the linking group Z is preferably a linking group containing an oxygen atom. Specifically, it includes -CO-, -O-CO-O-, -COO-, -O-, -CONH-, an epoxidized alkenylene group; a group in which a plurality of these groups are linked; a group in which one or more of these groups and one or more of divalent hydrocarbon groups are linked, etc. Examples of the divalent hydrocarbon group include those exemplified above.

[0043] Typical examples of alicyclic epoxy compounds represented by the above formula (I) include the compounds represented by the following formulas (I-1) to (I-10), bis(3,4-epoxycyclohexylmethyl) ether, 1,2-bis(3,4-epoxycyclohexane-1-yl)ethane, 1,2-epoxy-1,2-bis(3,4-epoxycyclohexane-1-yl)ethane, 2,2-bis(3,4-epoxycyclohexane-1-yl)propane, etc. In formulas (I-5) and (I-7) below, l and m represent integers from 1 to 30, respectively. In formula (I-5) below, R is an alkylene group having 1 to 8 carbon atoms, and examples include linear or branched alkylene groups such as methylene group, ethylene group, propylene group, isopropylene group, butylene group, isobutylene group, s-butylene group, pentylene group, hexylene group, heptylene group, and octylene group. Among these, linear or branched alkylene groups having 1 to 3 carbon atoms, such as methylene groups, ethylene groups, propylene groups, and isopropylene groups, are preferred. In the following formulas (I-9) and (I-10), n1 to n6 represent integers from 1 to 30.

[0044]

[0045]

[0046] Examples of compounds having an epoxy group directly bonded by a single bond to the alicyclic ring (ii) mentioned above include the compound represented by the following formula (II).

[0047]

[0048] In formula (II), R' is a group obtained by removing p hydroxyl groups (-OH) from the structural formula of a p-valent alcohol (a p-valent organic group), where p and n are natural numbers. p-valent alcohol [R'-(OH) ｐExamples of the compound represented by formula (II) above include polyhydric alcohols such as 2,2-bis(hydroxymethyl)-1-butanol (alcohols with 1 to 15 carbon atoms, etc.). p is preferably 1 to 6, and n is preferably 1 to 30. When p is 2 or more, the n in each group in parentheses (in the outer brackets) may be the same or different. Specific examples of the compound represented by formula (II) above include the 1,2-epoxy-4-(2-oxyranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol [for example, trade name "EHPE3150", manufactured by Daicel Corporation].

[0049] Examples of compounds having the above-mentioned (iii) alicyclic ring and glycidyl group include 2,2-bis[4-(2,3-epoxypropoxy)cyclohexyl]propane, 2,2-bis[3,5-dimethyl-4-(2,3-epoxypropoxy)cyclohexyl]propane, hydrogenated bisphenol A type epoxy resin, etc.; bis[o,o-(2,3-epoxypropoxy)cyclohexyl]methane, bis[o,p-(2,3-epoxypropoxy)cyclohexyl]methane, bis[p,p-(2,3-epoxypropoxy) Examples include hydrogenated cyclohexylmethane, bis[3,5-dimethyl-4-(2,3-epoxypropoxy)cyclohexyl]methane, bisphenol F type epoxy resins; hydrogenated biphenol type epoxy resins; hydrogenated phenol novolac type epoxy resins, hydrogenated cresol novolac type epoxy resins, hydrogenated cresol novolac type epoxy resins such as bisphenol A hydrogenated cresol novolac type epoxy resins; hydrogenated naphthalene type epoxy resins; and hydrogenated epoxy resins obtained from trisphenolmethane.

[0050] Other examples of the alicyclic epoxy compounds mentioned above include 1,2,8,9-diepoxylimonene.

[0051] As the above-mentioned alicyclic epoxy compound, commercially available products such as "Celoxide 2021P" and "Celoxide 2081" (both manufactured by Daicel Corporation) can also be used. Among these, the compound represented by the above formula (I-1) [3,4-epoxycyclohexylmethyl(3,4-epoxy)cyclohexanecarboxylate; for example, "Celoxide 2021P", manufactured by Daicel Corporation] is particularly preferred.

[0052] Examples of the above heterocyclic epoxy compounds include non-aromatic heterocycles such as tetrahydrofuran rings, tetrahydropyran rings, morpholine rings, chroman rings, isochroman rings, tetrahydrothiophene rings, tetrahydrothiopyran rings, aziridine rings, pyrrolidine rings, piperidine rings, piperazine rings, indoline rings, 2,6-dioxabicyclo[3.3.0]octane rings, 1,3,5-triazacyclohexane rings, and 1,3,5-triazacyclohexa-2,4,6-trione rings; and aromatic heterocycles such as thiophene rings, pyrrole rings, furan rings, and pyridine rings, which have a heterocycle other than an epoxy group and an epoxy group in their molecule.

[0053] The siloxane derivatives having one or more epoxy groups in the molecule as described above (sometimes referred to as "epoxy group-containing siloxane derivatives") are compounds having a siloxane skeleton composed of siloxane bonds (Si-O-Si) in the molecule and having one or more epoxy groups. Examples of the siloxane skeleton include cyclic siloxane skeletons; linear or branched silicones (linear or branched polysiloxanes); and polysiloxane skeletons such as cage-type or ladder-type polysilsesquioxanes. The number of epoxy groups in the molecule of the epoxy group-containing siloxane derivative is not particularly limited, but is preferably 2 to 4, and more preferably 3 or 4.

[0054] The epoxy compound (A) above preferably includes an alicyclic epoxy compound from among those described above, more preferably includes an aromatic epoxy compound in addition to the alicyclic epoxy compound, preferably includes an aromatic glycidyl ether type epoxy resin and / or an aromatic glycidylamine type epoxy resin as the aromatic epoxy compound, more preferably includes a bisphenol A type epoxy resin as the aromatic glycidyl ether type epoxy resin and a compound having a diglycidylaniline skeleton as the aromatic glycidylamine type epoxy resin, and particularly preferably includes N,N-bis(2,3-epoxypropyl)-o-toluidine as the compound having a diglycidylaniline skeleton.

[0055] The epoxy compound (A) described above can be manufactured by known or conventional methods, or a commercially available product can be used.

[0056] The proportion of the epoxy compound (A) in the resin composition of this disclosure is preferably 3 to 30% by mass, more preferably 4 to 25% by mass, and even more preferably 5 to 20% by mass, based on the total amount (100% by mass) of the resin composition. By setting the proportion of the epoxy compound (A) to 3% by mass or more, the curability of the resin composition tends to improve, and the heat resistance of the cured product tends to improve. On the other hand, by setting the proportion of the epoxy compound (A) to 30% by mass or less, the thermal shock resistance of the cured product tends to improve.

[0057] In the resin composition of this disclosure, when the epoxy compound (A) contains an alicyclic epoxy compound, the proportion of the alicyclic epoxy compound to the total amount (100% by mass) of epoxy compound (A) is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. By setting the proportion of epoxy compound (A) to 50% by mass or more, the heat resistance of the resin composition tends to be further improved, and the adhesion at high temperatures tends to be further improved. On the other hand, there is no particular upper limit, but it may be 100% by mass.

[0058] In the resin composition of this disclosure, if the epoxy compound (A) contains the aromatic epoxy compound in addition to the alicyclic epoxy compound, the ratio of the aromatic epoxy compound to the alicyclic epoxy compound (100 parts by mass) is preferably 5 to 50 parts by mass, more preferably 10 to 40 parts by mass, and even more preferably 12 to 30 parts by mass. By having the ratio of the aromatic epoxy compound within the above range, it becomes easier to reduce the viscosity while maintaining the heat resistance of the resin composition when it is cured.

[0059] Furthermore, the viscosity of the epoxy compound (A) alone, as measured at room temperature and a rotational speed of 0.01 to 100 rpm, is preferably 10 Pa·s or less, more preferably 5 Pa·s or less, and even more preferably 1 Pa·s or less. Having a viscosity of 10 Pa·s or less makes it easier to reduce the viscosity of the resin composition. While there is no particular lower limit, it is preferably 0.01 Pa·s or more.

[0060] <Acid anhydride (B)> The resin composition of this disclosure contains acid anhydride (B) as a curing agent. Acid anhydride (B) is a compound that hardens the resin composition by reacting with an epoxy compound. Furthermore, by using acid anhydride (B) as a curing agent, discoloration is suppressed and a cured product with excellent hue tends to be obtained. Only one type of acid anhydride (B) may be used, or two or more types may be used.

[0061] The above-mentioned acid anhydride (B) is not particularly limited, and a well-known and conventional acid anhydride can be used as a curing agent, for example, methyltetrahydrophthalic anhydride such as 4-methyltetrahydrophthalic anhydride and 3-methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride such as 4-methylhexahydrophthalic anhydride and 3-methylhexahydrophthalic anhydride, dodecenyl succinic anhydride, methylendomethylenetetrahydrophthalic anhydride, phthalic anhydride, maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylcyclohexendicarboxylic acid anhydride, pyromellitic anhydride, trimellitic anhydride, benzophenone Examples include tetracarboxylic anhydrides, nadic anhydrides, 1-methylnadic anhydrides, 5-methylnadic anhydrides, and other methylnadic anhydrides, hydrogenated methylnadic anhydrides, 4-(4-methyl-3-pentenyl)tetrahydrophthalic anhydride, succinic anhydride, adipic anhydride, sebacic anhydride, dodecanedioic anhydride, methylcyclohexenetetracarboxylic anhydride, vinyl ether-maleic anhydride copolymer, 1-methylnorbornane-2,3-dicarboxylic anhydride, 5-methylnorbornane-2,3-dicarboxylic anhydride, and other methylnorbornane-2,3-dicarboxylic anhydrides, norbornane-2,3-dicarboxylic anhydrides. In particular, from the viewpoint of ease of handling, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, dodecenyl succinic anhydride, methylendomethylenetetrahydrophthalic anhydride, etc. are preferred, and methylnadic anhydride is especially preferred in order to improve the glass transition temperature (Tg) of the resin composition. Furthermore, for acid anhydrides that are solid at room temperature, for example, dissolving them in an acid anhydride that is liquid at room temperature to form a liquid mixture tends to improve the handling of the acid anhydride (B) in the resin composition of this disclosure.

[0062] Furthermore, the viscosity of the acid anhydride (B) alone, measured at room temperature and a rotation speed of 0.01 to 100 rpm, is preferably 5 Pa·s or less, more preferably 1 Pa·s or less, and even more preferably 0.5 Pa·s or less. Having a viscosity of 5 Pa·s or less makes it easier to reduce the viscosity of the resin composition. While there is no particular lower limit, it is preferably 0.001 Pa·s or more.

[0063] As the above-mentioned acid anhydride (B), commercially available products can also be used, for example, the product names "Ricacid MH-700", "Ricacid MH-700F", and "HNA100" (all manufactured by Shin Nippon Rika Co., Ltd.); product name "HN-5500" (manufactured by Resonaq Corporation); product name "NMA" (manufactured by Polynt Corporation), etc.

[0064] The content of acid anhydride (B) in the resin composition of this disclosure is preferably 50 to 200 parts by mass, and more preferably 80 to 150 parts by mass, per 100 parts by mass of epoxy compound (A) contained in the resin composition of this disclosure. By setting the content of acid anhydride (B) to 50 parts by mass or more, curing can be sufficiently advanced, and the toughness of the cured product tends to be further improved. On the other hand, by setting the content of acid anhydride (B) to 200 parts by mass or less, discoloration is suppressed, and a cured product with excellent hue tends to be obtained.

[0065] Furthermore, in the resin composition of this disclosure, the equivalent ratio of the epoxy equivalent of the epoxy compound (A) to the acid anhydride equivalent of the acid anhydride (B) [epoxy equivalent of epoxy compound (A) / acid anhydride equivalent of acid anhydride (B)] is preferably 0.5 to 2.0, and more preferably 0.7 to 1.5. By having the equivalent ratio of epoxy compound (A) to acid anhydride (B) within the above range, curing can proceed sufficiently.

[0066] <Silica Filler (C)> The resin composition of the present disclosure contains silica filler (C). By including silica filler (C) in the resin composition of the present disclosure, the coefficient of linear expansion during heating in the cured product of the resin composition of the present disclosure can be reduced, and the adhesion to the adherend can be improved. Only one type of silica filler (C) may be used, or two or more types may be used.

[0067] The silica constituting the above-mentioned silica filler (C) can be manufactured by known or conventional methods such as wet methods like the sedimentation method or gel method, or dry methods like the combustion method or arc method. Examples include fumed silica, fused silica, crystalline silica, crushed silica, fine silica, high-purity synthetic silica, colloidal silica, and precipitated silica.

[0068] The above-mentioned silica filler (C) may be a silica filler that has been surface-treated with a surface treatment agent, or it may be an untreated silica filler. The above-mentioned surface-treated silica filler is preferably silica that has been surface-treated with at least one surface treatment agent selected from the group consisting of organosilicon compounds having alkylsilyl groups having 2 or more carbon atoms, organosilicon compounds having trimethylsilyl groups, and organosilicon compounds having linear or branched dimethylpolysiloxane groups. That is, the above-mentioned silica filler (C) preferably has at least one structural unit selected from the group consisting of structural units derived from organosilicon compounds having alkylsilyl groups having 2 or more carbon atoms, structural units derived from organosilicon compounds having trimethylsilyl groups, and structural units derived from organosilicon compounds having linear or branched dimethylpolysiloxane groups on its surface.

[0069] Examples of organosilicon compounds having an alkylsilyl group with 2 or more carbon atoms used as a surface treatment agent in the above-mentioned silica filler (C) include alkylsilanes having a linear or branched alkyl group with 2 to 20 carbon atoms, preferably 3 to 20, such as ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, i-propyltrimethoxysilane, i-propyltriethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, hexyltrimethoxysilane, heptyltrimethoxysilane, octyltrimethoxysilane, octyltrichlorosilane, octylsilane, octadecyltrichlorosilane, and hexadecylsilane. Examples of organosilicon compounds having a trimethylsilyl group include trimethylsilylation agents such as hexamethyldisilazane, trimethylsilyl chloride, trimethylmethoxysilane, and trimethylethoxysilane. Furthermore, examples of organosilicon compounds having linear or branched dimethylpolysiloxane groups include silicone oils having linear or branched dimethylpolysiloxane groups.

[0070] Furthermore, the above surface treatment agents can be used individually or in combination with two or more other agents. In addition, other surface treatment agents can be used in combination with the above surface treatment agent for manufacturing the silica filler (C).

[0071] The surface treatment of the raw silica can be carried out by known or conventional methods. Specifically, surface treatment methods include a dry method in which the raw silica is placed in a mixer such as a Henschel mixer or a V-type mixer and the above-mentioned surface treatment agent is added while stirring; a slurry method in which the above-mentioned surface treatment agent is added to a slurry of raw silica; and a spray method in which the above-mentioned surface treatment agent is sprayed onto the raw silica after drying. In the above surface treatment, the above-mentioned surface treatment agent can be used as is, or it can be used in the form of a solution or dispersion.

[0072] The shape of the silica filler (C) can be, for example, spherical, crushed, fibrous, needle-shaped, flaky, or whisker-shaped. Among these, a spherical shape is preferred from the viewpoint of dispersibility. Furthermore, the silica filler (C) may be hollow particles, solid particles, porous particles, etc.

[0073] The average primary particle diameter of the silica filler (C) is preferably 0.01 μm to 300 μm, more preferably 0.5 μm to 250 μm, and even more preferably 0.5 μm to 150 μm. When the average primary particle diameter of the silica filler (C) is 0.01 μm or more, it becomes easier to handle in terms of workability and safety. On the other hand, when the average primary particle diameter of the silica filler (C) is 300 μm or less, the transparency of the cured product obtained by curing the resin composition tends to be sufficient. The average primary particle diameter of the silica filler (C) can be measured, for example, by calculating the arithmetic mean of the primary particle diameters of 100 silica filler (C) particles using an electron microscope such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM).

[0074] The content (amount blended) of the silica filler (C) in the resin composition of this disclosure is preferably 50 to 90% by mass, more preferably 55 to 85% by mass, and even more preferably 60 to 80% by mass, based on the total amount (100% by mass) of the resin composition. When the silica filler (C) content is 50% by mass or more, the coefficient of linear expansion during heating can be reduced, and adhesion at high temperatures can be improved. On the other hand, when the silica filler (C) content is 90% by mass or less, it becomes easier to lower the viscosity of the resin composition at room temperature.

[0075] <Curing Accelerator (D)> The resin composition of this disclosure contains a curing accelerator (D). The curing accelerator (D) is a compound that has the function of accelerating the curing rate when the epoxy compound (A) is cured by the acid anhydride (B). Only one type of curing accelerator (D) may be used, or two or more types may be used.

[0076] As the curing accelerator (D) above, known or conventional curing accelerators can be used, for example, 1,8-diazabicyclo[5.4.0]undecene-7 (DBU), and its salts (e.g., phenol salt, octyl salt, p-toluenesulfonate, formate, tetraphenylborate salt, etc.); 1,5-diazabicyclo[4.3.0]nonene-5 (DBN), and its salts (e.g., phenol salt, octyl salt, p-toluenesulfonate, formate, tetraphenylborate salt, etc.); benzyldimethylamine, 2, Examples include tertiary amines such as 4,6-tris(dimethylaminomethyl)phenol and N,N-dimethylcyclohexylamine; imidazoles such as 1-benzyl-2-methylimidazole, 2-ethyl-4-methylimidazole, and 1-cyanoethyl-2-ethyl-4-methylimidazole; phosphines such as phosphate esters and triphenylphosphine; phosphonium compounds such as tetraphenylphosphonium tetra(p-tolyl)borate; organometallic salts such as tin octate and zinc octate; and metal chelates.

[0077] The content of the curing accelerator (D) is not particularly limited, but is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, and even more preferably 0.2 to 3 parts by mass, relative to the total amount (100 parts by mass) of the epoxy compound (A) contained in the resin composition of this disclosure. When the content of the curing accelerator (D) is 0.05 parts by mass or more, the curing acceleration effect can be sufficiently exhibited. On the other hand, when the content of the curing accelerator (D) is 5 parts by mass or less, discoloration of the cured product and deterioration of hue can be suppressed.

[0078] <Flame retardant (E) containing phosphorus-based components> The resin composition of this disclosure contains a flame retardant (E) containing phosphorus-based components. By including the above-mentioned flame retardant (E) containing phosphorus-based components, gas generation at high temperatures due to heat is suppressed, so the change in thickness due to expansion is small and the heat resistance at high temperatures is excellent, while the flame retardant can be exhibited by acting on the resin composition during combustion to form a carbonized layer. Only one type of the above-mentioned flame retardant (E) containing phosphorus-based components may be used, or two or more types may be used.

[0079] Examples of phosphorus-based components included in the above-mentioned flame retardant (E) include phosphazene compounds, phosphorus compounds containing spiro rings, red phosphorus, phosphate esters, (poly)phosphate, salts of (poly)phosphate and nitrogen compounds, metal polyphosphate salts, metal phosphinate salts, and the like.

[0080] The above-mentioned phosphazene compounds are preferably phenoxyphosphazene compounds, and specifically include compounds having a cyclic structure represented by the following formula (A) and compounds having a chain-like structure represented by the following formula (B).

[0081]

[0082]

[0083] In formula (A) above, q and in formula (B) above, r each represent an integer from 1 to 20. In this disclosure, it is preferable that q or r is 2 or greater.

[0084] The phosphorus-based compound containing the above-mentioned spiro ring preferably contains a phosphonic acid diester structure, and more specifically, it preferably contains a structure represented by the following formula (C).

[0085]

[0086] In the above formula (C), R １ This is a substituted or unsubstituted alkyl group, an aromatic hydrocarbon group, or an aromatic heterocyclic group. * indicates a site that bonds to the organic group constituting the phosphate ester.

[0087] In the above formula (C), R １The number of carbon atoms in the alkyl group represented by is preferably 1 to 10, more preferably 1 to 5, and even more preferably 1 to 3. Examples of the alkyl group include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl groups. These alkyl groups may be linear or branched. The alkyl group may have substituents or may not have substituents. Examples of substituents include aromatic hydrocarbon groups (described later), aromatic heterocyclic groups (described later), halogen atoms, alkoxy groups, aryloxy groups, hydroxyl groups, carboxyl groups, amino groups, glycidyl ether groups, and groups formed by combining these. The number of carbon atoms in the substituent of the alkyl group is preferably 1 to 20, more preferably 1 to 12, and even more preferably 1 to 10.

[0088] In the above formula (C), R １ The number of carbon atoms in the aromatic hydrocarbon group represented is preferably 6 to 20, more preferably 6 to 15, and even more preferably 6 to 12. Examples of the above aromatic hydrocarbon group include a phenyl group and a naphthyl group. The above aromatic hydrocarbon group may or may not have substituents. Examples of the above substituents include the alkyl group described above; aromatic heterocyclic groups described later; halogen atoms; alkoxy groups, aryloxy groups, hydroxyl groups, carboxyl groups, amino groups, glycidyl ether groups; and groups that are combinations of these. The number of carbon atoms in the substituent of the aromatic hydrocarbon group is preferably 1 to 20, more preferably 1 to 12, and even more preferably 1 to 10.

[0089] In the above formula (C), R １The number of carbon atoms in the aromatic heterocyclic group represented by is preferably 6 to 20, more preferably 6 to 15, and even more preferably 6 to 12. Examples of the aromatic heterocyclic group include aromatic heterocyclic residues such as pyridine, pyridazine, pyrimidine, pyrazine, 1,3,5-triazine, carbazole, dibenzofuran, dibenzothiophene, phenoxazine, phenothiazine, and dihydroacridine. The aromatic heterocyclic group may or may not have substituents. Examples of the substituents include the alkyl groups described above; the aromatic hydrocarbon groups described above; halogen atoms; alkoxy groups, aryloxy groups, hydroxyl groups, carboxyl groups, amino groups, glycidyl ether groups; and groups formed by combining these. The number of carbon atoms in the substituents of the aromatic heterocyclic group is preferably 1 to 20, more preferably 1 to 12, and even more preferably 1 to 10.

[0090] R explained above １ Among these options, from the viewpoint of flame retardancy, a substituted or unsubstituted alkyl group is preferred, a alkyl group substituted with an aromatic hydrocarbon group is more preferred, and a alkyl group substituted with a phenyl group is even more preferred.

[0091] The phosphorus-based compound containing the above-mentioned spiro ring preferably has 1 to 5 phosphorus atoms in its molecular structure, more preferably 1 to 3, and even more preferably 2.

[0092] Furthermore, the number of ring members of the two rings constituting the spiro ring in the phosphorus compound containing the spiro ring is preferably 4 to 10, more preferably 5 to 8, even more preferably 5 to 7, and particularly preferably 6. That is, the spiro ring in the phosphorus compound containing the spiro ring preferably has a structure in which two 6-membered rings share one atom, and more preferably has a structure in which two 6-membered rings share one carbon atom.

[0093] Examples of the phosphorus-based compound containing the above spiro ring include 3,9-bis(phenylmethyl)-3,9-dioxo-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, 3,9-bis(1-phenylethyl)-3,9-dioxo-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, 3,9-bis(2-phenylethyl)-3,9-dioxo-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, 3,9-bis(diphenylmethyl)-3,9-dioxo-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, and the like.

[0094] Examples of the above phosphate ester include tri(alkylphenyl) phosphate, di(alkylphenyl) monophenyl phosphate, diphenyl mono(alkylphenyl) phosphate, triphenyl phosphate, and compounds represented by the following formula (D).

[0095]

[0096] In the above formula (D), R ２ to R ６ each independently represents a group containing an aromatic ring. s represents 1 to 10,000.

[0095]

[0096] In the above formula (D), R ２ to R ６ each independently represents a group containing an aromatic ring. s represents 1 to 10,000.

[0097] R ２ to R ６ are preferably aryl or aryl groups substituted with alkyl, and preferred R ２ R ３ R ５ and R ６ are phenyl groups, or phenyl groups substituted with an alkyl group such as a methyl group, an ethyl group, an isopropyl group, a t-butyl group, an isobutyl group, an isoamyl group, a t-amyl group, etc. Among these, phenyl groups, or phenyl groups substituted with a methyl group, an ethyl group, an isopropyl group, or a t-butyl group are more preferred, and R ４ is preferably an aryl or aryl group derivative substituted with alkyl, and more preferably those derived from resorcinol, hydroquinone or bisphenol-A.

[0098] Examples of the above-mentioned salts of (poly)phosphate and nitrogen compounds include ammonium salts and amine salts of (poly)phosphate, such as ammonium polyphosphate, melamine polyphosphate, piperazine polyphosphate, ammonium pyrophosphate, melamine pyrophosphate, and piperazine pyrophosphate. In particular, it is especially preferable that the salt of the above-mentioned salt of (poly)phosphate and nitrogen compound includes a compound having a melamine structure and / or a piperazine structure.

[0099] Furthermore, the nitrogen compound may be any nitrogen compound other than ammonia, melamine, and piperazine. Examples of the other nitrogen compounds include N,N,N',N'-tetramethyldiaminomethane, ethylenediamine, N,N'-dimethylethylenediamine, N,N'-diethylethylenediamine, N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-diethylethylenediamine, 1,2-propanediamine, 1,3-propanediamine, and tetramethylethylenediamine. Diamine, pentamethylenediamine, hexamethylenediamine, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, trans-2,5-dimethylpiperazine, 1,4-bis(2-aminoethyl)piperazine, 1,4-bis(3-aminopropyl)piperazine, acetoguanamine, benzoguanamine, acrylicguanamine, 2,4-diamino-6-nonyl-1,3,5-tri Azine, 2,4-diamino-6-hydroxy-1,3,5-triazine, 2-amino-4,6-dihydroxy-1,3,5-triazine, 2,4-diamino-6-methoxy-1,3,5-triazine, 2,4-diamino-6-ethoxy-1,3,5-triazine, 2,4-diamino-6-propoxy-1,3,5-triazine, 2,4-diamino-6-isopropoxy-1,3,5-triazine, 2,4-diamino-6-mercapto-1, Examples include 3,5-triazine, 2-amino-4,6-dimercapto-1,3,5-triazine, ammeline, benzguanamine, acetoguanamine, phthalodiguanamine, melamine cyanurate, melamine pyrophosphate, butylenediguanamine, norbornenediguanamine, methylenediguanamine, ethylenedimelamine, trimethylenedimelamine, tetramethylenedimelamine, hexamethylenedimelamine, and 1,3-hexylenedimelamine.

[0100] In particular, as a flame retardant containing the phosphorus-based component mentioned above, it is preferable to include at least one of phosphazene compounds, phosphorus compounds containing a spiro ring, a salt of (poly)phosphate and a nitrogen compound, and a phosphorus ester, from the viewpoint of exhibiting excellent flame retardancy. It is more preferable to include a phosphorus compound containing a spiro ring and / or a salt of (poly)phosphate and a nitrogen compound, as this makes it easier to suppress gas generation during heating. It is especially preferable to include a phosphazene compound and a phosphorus compound containing a spiro ring and / or a salt of (poly)phosphate and a nitrogen compound.

[0101] The content of the flame retardant (E) containing the phosphorus component described above is not particularly limited, but is preferably 2 to 20% by mass, more preferably 3 to 15% by mass, and even more preferably 4 to 10% by mass, based on the total amount (100% by mass) of the resin composition of this disclosure. By setting the proportion of the flame retardant (E) containing the phosphorus component to 2% by mass or more, the flame retardant tends to be easily exhibited. On the other hand, by setting the proportion of the flame retardant (E) containing the phosphorus component to 20% by mass or less, the viscosity of the entire resin composition can be kept low.

[0102] <Other Flame Retardants (F)> The resin composition of this disclosure may also contain other flame retardants (F) other than the phosphorus-based flame retardant (E) described above. Specifically, examples of the other flame retardants (F) include halogen-based flame retardants and inorganic flame retardants, and it is more preferable to include inorganic flame retardants from the viewpoint of exhibiting reliability at high temperatures. In addition, halogen-based flame retardants may be included as the other flame retardants (F), but it is preferable not to include them.

[0103] Examples of the inorganic flame retardants mentioned above include magnesium oxide, calcium oxide, aluminum oxide, zinc oxide, manganese oxide, tin oxide, antimony oxide, boehmite, dihydrotalcite, hydrocalmite, magnesium hydroxide, calcium hydroxide, aluminum hydroxide, zinc hydroxide, tin oxide hydrate, manganese hydroxide, zinc borate, basic zinc silicate, and zinc stannate.

[0104] When the inorganic flame retardant is included as the other flame retardant (F) mentioned above, its content is not particularly limited, but is preferably 0.1 to 10% by mass, more preferably 0.5 to 8% by mass, and even more preferably 1 to 6% by mass, based on the total amount (100% by mass) of the resin composition of this disclosure. By setting the proportion of the inorganic flame retardant to 0.1% by mass or more, it tends to exhibit flame retardancy when combined with a flame retardant (E) containing a phosphorus component. On the other hand, by setting the proportion of the inorganic flame retardant to 10% by mass or less, the viscosity of the entire resin composition can be kept low.

[0105] Furthermore, the total content of all flame retardants is not particularly limited, but is preferably 2 to 30% by mass, more preferably 3 to 20% by mass, and even more preferably 4 to 15% by mass, based on the total amount (100% by mass) of the resin composition of this disclosure. By setting the proportion of flame retardants to 2% by mass or more, flame retardancy tends to be easily exhibited. On the other hand, by setting the proportion of flame retardants to 30% by mass or less, the viscosity of the entire resin composition can be kept low.

[0106] <Other Components> The resin composition of this disclosure may contain other components in addition to the components described above. Examples of these other components include, for example, curable components other than those described above, thermoplastic resins, curing catalysts, antioxidants, UV absorbers, light stabilizers, heat stabilizers and other stabilizers, reinforcing agents, nucleating agents, lubricants, waxes, plasticizers, mold release agents, impact resistance modifiers, hue modifiers, flow modifiers, colorants such as dyes and pigments, surface modifiers such as various polyether-modified silicones, polyester-modified silicones, phenyl-modified silicones, and alkyl-modified silicones, dispersants, defoamers, antibacterial agents, preservatives, viscosity modifiers, thickeners, and other functional additives (for example, zinc compounds such as zinc salts of carboxylic acids). Only one of these other components may be used, or two or more may be used. The content (amount) of these other components is not particularly limited, but is preferably 10% by mass or less, more preferably 5% by mass or less, and may be 0% by mass, based on the total amount (100% by mass) of the resin composition of this disclosure.

[0107] Furthermore, the resin composition of this disclosure may contain an organic solvent as one of the other components mentioned above, but preferably in an amount of 10% by mass or less, more preferably 1% by mass or less, and even more preferably 0% by mass, based on the total amount (100% by mass) of the resin composition. In other words, it is preferable that the resin composition of this disclosure does not contain an organic solvent.

[0108] The resin compositions of this disclosure are not particularly limited, but can be prepared by stirring and mixing each of the above components while heating as needed. The resin compositions of this disclosure can be used as a one-component composition in which the components are pre-mixed and used as is, or they can be used as a multi-component (e.g., two-component) composition in which two or more components stored separately are mixed in a predetermined ratio before use. The stirring and mixing method is not particularly limited, and known or conventional stirring and mixing means such as various mixers such as dissolvers and homogenizers, kneaders, rolls, bead mills, and self-rotating stirring devices can be used. Furthermore, after stirring and mixing, degassing may be performed under vacuum.

[0109] <Cured Product> A cured product can be obtained by curing the resin composition of this disclosure. The cured product exhibits excellent adhesion even in high-temperature environments, and a highly reliable cured product can be obtained. The heating temperature during curing (curing temperature) is not particularly limited, but is preferably 50 to 300°C, and more preferably 80 to 200°C. The heating time during curing (curing time) is not particularly limited, but is preferably 30 minutes to 10 hours, and more preferably 1 hour to 6 hours. When the curing temperature and curing time are higher than the lower limit of the above range, curing is more easily achieved, and conversely, when they are lower than the upper limit of the above range, yellowing due to thermal decomposition is less likely to occur, which is preferable. The curing conditions depend on various conditions, but can be appropriately adjusted, for example, by shortening the curing time when the curing temperature is high, and lengthening the curing time when the curing temperature is low. Furthermore, the curing treatment may be carried out in one stage, or it may be carried out in multiple stages (secondary curing), for example, by further heating in an oven. Furthermore, when curing is performed in multiple stages, the heating temperature at this time is preferably 100 to 250°C, more preferably 130 to 220°C, and even more preferably a temperature similar to the curing temperature.

[0110] <Resin composition for semiconductor encapsulation> Furthermore, the resin composition of this disclosure can be used as a resin composition for semiconductor encapsulation. By using the resin composition of this disclosure as the above-mentioned resin composition for semiconductor encapsulation, it is easy to handle because it has low viscosity even without containing a solvent, and potting encapsulation is possible. After curing, the cured product (encapsulant) has high reliability even at high temperatures, and semiconductor elements can be encapsulated with it. Since the cured product of the above-mentioned resin composition for semiconductor encapsulation has reliability in high-temperature environments, it can be suitably used as an encapsulant for power semiconductors, for example, when the semiconductor device is equipped with high-power semiconductor elements.

[0111] <Semiconductor Device> Furthermore, a semiconductor device can be used in which a semiconductor element is encapsulated by a cured product of the resin composition (resin composition for semiconductor encapsulation) of the present disclosure. The encapsulation of the semiconductor element can be performed by injecting the resin composition prepared by the method described above by potting encapsulation and heating and curing it under predetermined conditions. As a result, a semiconductor device can be obtained in which the semiconductor element is encapsulated by a cured product of the resin composition of the present disclosure, and which is reliable even in high-temperature environments. The curing temperature and curing time can be set within the same range as when preparing the cured product.

[0112] Each embodiment disclosed herein can be combined with any other features disclosed herein. Furthermore, each configuration and combination thereof in each embodiment is an example, and additions, omissions, and other modifications are permitted as appropriate, without departing from the spirit of this disclosure. This disclosure is not limited by the embodiments, but is limited only by the claims.

[0113] An embodiment of this disclosure will be described in more detail below based on examples.

[0114] Examples 1-5, Comparative Examples 1-3 (Preparation of Resin Compositions) Components (A) to (E) listed in Table 1 were mixed in a cup container in the mass ratio shown in Table 1. Mixing and degassing were performed using a vacuum degassing and stirring machine (product name "Jisen-Koten Mixer Awatori Rentaro Vacuum Type ARV-310", manufactured by Shinky Co., Ltd.) to prepare the resin compositions of the Examples and Comparative Examples, which are liquid at room temperature.

[0115] The components listed in Table 1 are described in detail below. Table 1 shows the amount (parts by mass) of each agent. (Epoxy compound (A)) A-1: ​​3,4-Epoxycyclohexylmethyl(3,4-epoxy)cyclohexanecarboxylate, trade name "Ceroxite 2021P", manufactured by Daicel Corporation, epoxy equivalent: 130 g / eq A-2: N,N-bis(2,3-epoxypropyl)-o-toluidine, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 131 g / eq A-3: Poly[2-(chloromethyl)oxirane-alt-4,4'-(propane-2,2-diyl)diphenol] (bisphenol A type epoxy resin), trade name "YD-128", manufactured by Nippon Steel Chemical & Material Co., Ltd., epoxy equivalent: 189 g / eq A-4: Polycondensate of 4,4'-isopropylidenebis(2,6-dibromophenol)・1-chloro-2,3-epoxypropane, trade name "NPEB-400", manufactured by Nanya Co., Ltd., epoxy equivalent: 385 g / eq (acid anhydride (B)) B-1: Liquid alicyclic acid anhydride, trade name "Ricajit MF-700F", manufactured by Shin Nippon Rika Co., Ltd., acid anhydride equivalent: 163 g / eq B-2: Methylnadic anhydride, trade name "NMA", manufactured by Polynt, acid anhydride equivalent: 176.2 g / eq B-3: Hydrogenated methylnadic anhydride, trade name "HNA100", manufactured by Shin Nippon Rika Co., Ltd., acid anhydride equivalent: 184 g / eq (silica filler (C)) C-1: Silica filler, average particle size 30 μm, trade name "FB-950", manufactured by Denka Co., Ltd. (curing accelerator (D)) D-1: Imidazole catalyst, trade name "1B2MZ", manufactured by Shikoku Chemicals, Inc. (flame retardant containing phosphorus components (E)) E-1: Phosphazene oligomer, trade name "Rabitol FP-100", manufactured by Fushimi Pharmaceutical Co., Ltd. E-2: Spiro ring diphosphonate flame retardant, trade name "FCX-210", manufactured by Teijin Ltd. E-3: Condensed phosphate ester flame retardant, trade name "FP-600", manufactured by ADEKA Corporation E-4: Intomescent flame retardant, trade name "FP-2500S", composite containing a phosphate compound, manufactured by ADEKA Corporation (other flame retardants (F)) F-1: Zinc stannate, trade name "Flamtard H", manufactured by Nippon Light Metal Co., Ltd. F-2: Oligomer-type brominated flame retardant, trade name "FC-210HR", manufactured by Tosoh Corporation F-3: Brominated aromatic triazine, trade name "Piroguard SR-245", manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

[0116] The above resin compositions were evaluated as follows, and the results are shown in Table 1.

[0117] [Evaluation] (1) Glass transition temperature (Tg), coefficient of linear expansion (α1, α2) The resin compositions obtained in the examples and comparative examples were heated at 100°C for 2 hours, followed by 200°C for 2 hours to cure them and obtain cured products. The glass transition temperature and coefficient of linear expansion (α1, α2) of the above cured products were determined under the following conditions. Sample size: Length 20 mm x Width 10 mm x Thickness 10 mm Measurement device: Thermomechanical measuring device (TMA), product name "TMA / SS6000", manufactured by Seiko Instruments Corporation Measurement mode: Compression, constant load measurement Measurement temperature: Heating from 25°C to 240°C at 5°C / min, rapid cooling from 240°C to 20°C at 10°C / min, heating from 20°C to 260°C at 5°C / min Coefficient of linear expansion: α1 60-80°C, α2 240-260°C (measured)

[0118] (2) The resin compositions obtained in the flame retardancy examples and comparative examples were heated at 100°C for 2 hours, followed by 200°C for 2 hours to cure them and obtain cured test specimens. The flame retardancy of the cured specimens was determined by the following evaluation method. Sample size: length 125 mm x width 13 mm x t2 Test standard: UL-94 Test method: The upper end of the test specimen was fixed at 6 mm and held vertically. The burner was brought horizontally towards the wider side of the test specimen at a rate of 300 mm / second. The tip of the burner was adjusted to be 10 ± 1 mm from the lower end of the test specimen, and the flame was applied for 10 ± 0.5 seconds. After flame application, the burner was moved at a speed of 300 mm / second away from the lower end of the test specimen by 150 mm or more, and the afterflame time (and red-hot time) was measured at the same time. If the test specimen shrunk or warped, the burner was moved to an appropriate position. If the test specimen dripped, the burner was tilted to 45 ± 5°C for the test. Once combustion stops, immediately adjust the burner tip so that it is 10 ± 1 mm below the remaining portion of the test specimen, and apply the flame for 10 ± 0.5 seconds, then measure the afterflame time (and red-hot time). Using the above method, measure the combustion rate of the material, the total afterflame time after two flame applications, and the presence or absence of dripping material, and evaluate them according to the UL-94 standard. If the material burns for 30 seconds or more after the first flame application, do not apply the flame a second time.

[0119] (3) Long-term heat resistance test The resin compositions obtained in the examples and comparative examples were heated at 100°C for 2 hours, followed by 200°C for 2 hours to cure them and obtain cured test specimens. The long-term heat resistance of the above test specimens was evaluated by the following method. Sample size: thickness 2 mm, width 3 cm, length 5 cm Test method: The weight before and after storage was measured using a precision balance when the specimens were stored for 1000 hours in an oven (product name "YAMATO DKN302", manufactured by Yamato Scientific Co., Ltd.) kept at 200°C, and the weight retention rate during the storage test was calculated. In addition, the appearance of the test specimens after storage was evaluated, and those that showed no change from before storage were marked with ○, those whose shape did not change significantly from before storage but showed cracks on part of the surface were marked with △, and those that showed cracks or bulges throughout were marked with ×.

[0120]

[0121] The resin compositions in the examples showed minimal change in thickness even after curing and long-term heat resistance testing at a high temperature of 200°C. Furthermore, the UL94 standard test results were V-1 or higher, indicating excellent reliability at high temperatures after curing. On the other hand, when no flame retardant containing phosphorus components was included (Comparative Example 1) or when a brominated flame retardant was used (Comparative Examples 2 and 3), the thickness changed significantly in long-term heat resistance testing, resulting in insufficient reliability.

[0122] Variations of this disclosure are described below. [Appendix 1] A resin composition comprising an epoxy compound (A), an acid anhydride (B), a silica filler (C), a curing accelerator (D), and a flame retardant (E) containing a phosphorus-based component, having a glass transition temperature (Tg) of 160°C or higher and being liquid at room temperature. [Appendix 2] The resin composition according to Appendix 1, which hardens into a shape with a thickness of 2 mm, a width of 3 cm, and a length of 5 cm, and the rate of change in thickness after heating at 200°C for 1000 hours is 5% or less. [Appendix 3] The resin composition according to Appendix 1 or 2, which, after hardening, has flame retardancy rated as V-1 or higher in a vertical combustion test in accordance with the UL94 standard. [Appendix 4] The resin composition according to any one of Appendixes 1 to 3, which hardens into a shape with a thickness of 2 mm, a width of 3 cm, and a length of 5 cm, and the weight retention rate after heating at 200°C for 1000 hours is 85% or more. [Note 5] The resin composition according to any one of Notes 1 to 4, wherein the epoxy compound (A) comprises an alicyclic epoxy compound. [Note 6] The resin composition according to Note 5, wherein the epoxy compound (A) further comprises an aromatic glycidyl ether type epoxy resin and / or an aromatic glycidylamine type epoxy resin. [Note 7] The resin composition according to Note 6, wherein the aromatic glycidyl ether type epoxy resin comprises a bisphenol A type epoxy resin, and the glycidylamine type epoxy resin comprises a compound having a diglycidylaniline skeleton. [Note 8] The resin composition according to Note 7, wherein the compound having a diglycidylaniline skeleton comprises N,N-bis(2,3-epoxypropyl)-o-toluidine. [Note 9] The resin composition according to any one of Notes 1 to 8, further comprising an inorganic flame retardant.

Claims

1. A resin composition comprising an epoxy compound (A), an acid anhydride (B), a silica filler (C), a curing accelerator (D), and a flame retardant (E) containing a phosphorus-based component, having a glass transition temperature (Tg) of 160°C or higher, and being liquid at room temperature.

2. The resin composition according to claim 1, wherein it hardens into a shape with a thickness of 2 mm, a width of 3 cm, and a length of 5 cm, and the rate of change in thickness after heating at 200°C for 1000 hours is 5% or less.

3. The resin composition according to claim 1 or 2, which, after curing, has flame retardancy rated as V-1 or higher in a vertical combustion test in accordance with the UL94 standard.

4. The resin composition according to claim 1 or 2, wherein it hardens into a shape with a thickness of 2 mm, a width of 3 cm, and a length of 5 cm, and the weight retention rate after heating at 200°C for 1000 hours is 85% or more.

5. The resin composition according to claim 1 or 2, wherein the epoxy compound (A) comprises an alicyclic epoxy compound.

6. The resin composition according to claim 5, further comprising an aromatic glycidyl ether type epoxy resin and / or an aromatic glycidylamine type epoxy resin as the epoxy compound (A).

7. The resin composition according to claim 6, comprising a bisphenol A type epoxy resin as the aromatic glycidyl ether type epoxy resin, and comprising a compound having a diglycidylaniline skeleton as the glycidylamine type epoxy resin.

8. The resin composition according to claim 7, comprising N,N-bis(2,3-epoxypropyl)-o-toluidine as the compound having the diglycidylaniline skeleton.

9. The resin composition according to claim 1 or 2, further comprising an inorganic flame retardant.

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