Phenolic resin composition, epoxy resin composition containing the same, cured product of the epoxy resin composition, and semiconductor device having the cured product

Abstract

To provide a phenolic resin composition used for an epoxy resin composition containing a phenolic resin and an epoxy resin, which gives an epoxy resin cured product having excellent tracking resistance and flame retardancy and also having heat resistance, moisture resistance and excellent mechanical characteristics and the like.SOLUTION: The present disclosure provides a phenolic resin composition used for an epoxy resin composition containing a phenolic resin and an epoxy resin, which gives an epoxy resin cured product that contains a biphenyl aralkyl phenolic resin with a residual carbon rate of 20% or more at 550°C by TG / DTA in an N2 atmosphere, and melamine cyanurate, with a tracking resistance index of 550 V or more and a flame retardancy of V-0 in the UL-94 test.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a phenolic resin composition containing a phenolic resin and melamine cyanurate, and an epoxy resin composition containing the same. [Background technology]

[0002] In recent years, the voltages and currents of electrical and electronic equipment have become higher. Devices used in these devices are required to have electrical insulation performance under high voltages and currents, and as devices become lighter, thinner, shorter, and smaller, the wiring pitch also becomes narrower, so the encapsulating materials used are required to have even higher insulation performance, and in particular, there is an increasing demand for tracking resistance, which is one indicator of electrical insulation performance. On the other hand, the encapsulating materials used in such devices are still required to have various physical properties such as flame retardancy as before, and there is also a high demand for heat resistance in automotive applications where they are used under high voltages and currents.

[0003] Conventionally used phenolic resins, particularly biphenylaralkyl-type phenolic resins used as flame-retardant phenolic resins, have many aromatic rings, and therefore tend to form carbonized conductive paths and have insufficient tracking performance. On the other hand, phenolic resins having an alicyclic structure such as dicyclopentadiene are unlikely to form carbonized conductive paths derived from aromatic rings, and therefore can ensure tracking performance but are insufficient in heat resistance and flame retardancy.

[0004] In addition, a method for improving flame retardancy and tracking properties by using metal hydroxides has been proposed, but this requires a large amount of additive, and there are problems such as deterioration of moisture resistance reliability due to the release of water of crystallization. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2006-036939 A [Patent Document 2] JP 2008-143950 A Summary of the Invention [Problem to be solved by the invention]

[0006] The main object of the present invention is to provide a phenolic resin composition for use in an epoxy resin composition containing a phenolic resin and an epoxy resin, which gives an epoxy resin cured product having excellent tracking resistance and flame retardancy as well as heat resistance, moisture resistance, and good mechanical properties. [Means for solving the problem]

[0007] As a result of intensive research by the present inventors, it has become clear that an epoxy resin cured product obtained from a phenolic resin composition containing a specific phenolic resin and melamine cyanurate, and an epoxy resin composition containing an epoxy resin has a desired performance.

[0008] The present invention relates to a compound represented by the following general formula (1): 2 The phenolic resin composition contains a phenolic resin having a carbon residual rate of 20% or more at 550°C as determined by TG / DTA under atmospheric conditions, and melamine cyanurate, and is used in an epoxy resin composition containing a phenolic resin and an epoxy resin, which gives an epoxy resin cured product having a tracking resistance index of 550V or more and a flame retardancy of V-0 in a UL-94 test.

[0009] [ka] (In the formula, rings Ar each independently represent a benzene ring or a naphthalene ring, L each independently represent a divalent group represented by the following formulas (a) to (d), R each independently represent a hydroxyl group, an alkyl group, an aryl group or an arylalkyl group, p, q and r each independently represent an integer of 0 or 1, and n represents an integer of 0 to 20.)

[0010] [ka] (In formula (a), each R' independently represents a hydrogen atom, a methyl group, an ethyl group, or a propyl group.)

[0011] The present invention also relates to an epoxy resin composition comprising the above phenolic resin composition, an epoxy resin, and a curing accelerator.

[0012] Furthermore, the present invention relates to a method for improving the tracking resistance of a cured product of an epoxy resin composition comprising a phenolic resin and an epoxy resin, by adding melamine cyanurate to the epoxy resin composition. Effect of the Invention

[0013] According to the present invention, it is possible to provide a phenolic resin composition for use in an epoxy resin composition containing a phenolic resin and an epoxy resin, which gives an epoxy resin cured product having excellent tracking resistance and flame retardancy, as well as heat resistance, moisture resistance, and good mechanical properties, etc. It is also possible to provide a method for improving the tracking resistance of an epoxy resin cured product by using melamine cyanurate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The phenolic resin composition of the present invention is used to obtain an epoxy resin cured product having particularly excellent tracking resistance and flame retardancy. Tracking resistance was measured according to JIS C 2134. Comparison The tracking index can be used to evaluate the phenolic resin composition. Comparison It is used to obtain an epoxy resin cured product having a tracking index of 550 V or more. In addition, flame retardancy can be evaluated according to the UL-94 standard, and the phenolic resin composition is used to obtain an epoxy resin cured product having a flame retardancy of V-0 in the UL-94 test.

[0015] The phenolic resin used in the phenolic resin composition of the present invention is represented by the above general formula (1), 2There are no particular limitations as long as the phenol resin has a residual carbon ratio of 20% or more at 550° C. as determined by TG / DTA under an atmosphere. The above carbon content is N 2 This is the weight retention rate at 550°C when TG / DTA is performed under atmospheric conditions.

[0016] In the present invention, the carbon residual ratio is 20% or more, but from the viewpoint of flame retardancy, it is more preferably 30% or more, even more preferably 40% or more, and particularly preferably 45% or more. Also, from the viewpoint of tracking resistance, the carbon residual ratio is preferably 60% or less, more preferably 55% or less, and even more preferably 50% or less. In the present invention, from the viewpoint of achieving both flame retardancy and tracking resistance, the carbon residue ratio is preferably 20 to 60%, more preferably 30 to 60%, even more preferably 40 to 55%, and particularly preferably 45 to 55%.

[0017] The phenol resin includes novolac type phenol resin, triphenylmethane type phenol resin, aralkyl type phenol resin and modified aralkyl type phenol resin.

[0018] The novolac phenolic resin is a phenolic resin obtained by condensing or co-condensing at least one phenol selected from the group consisting of phenolic compounds such as phenol, cresol, xylenol, resorcin, catechol, bisphenol A, bisphenol F, etc., and naphthol compounds such as α-naphthol, β-naphthol, dihydroxynaphthalene, etc., with an aliphatic aldehyde compound such as formaldehyde, acetaldehyde, propionaldehyde, etc., in the presence of an acidic catalyst. In the above general formula (1), the phenol resin in which L is represented by the above formula (a) corresponds to a novolac-type phenol resin.

[0019] The aralkyl type phenol resin is a phenol resin obtained by condensing or co-condensing the above phenols with aromatic bismethoxymethyl compounds such as bis(methoxymethyl)benzenes such as 1,4'-bis(methoxymethyl)benzene and bis(methoxymethyl)biphenyls such as 4,4'-bis(methoxymethyl)-1,1'-biphenyl, or aromatic bishalogenomethyl compounds such as bis(halogenomethyl)benzenes such as 1,4'-bis(chloromethyl)benzene and bis(halogenomethyl)biphenyls such as 4,4'-bis(chloromethyl)-1,1'-biphenyl, in the presence or absence of an acidic catalyst. In the above general formula (1), the phenol resin in which L is represented by the above formulas (b) and (c) corresponds to an aralkyl-type phenol resin.

[0020] The triphenylmethane type phenolic resin is a phenolic resin obtained by condensing or co-condensing the above phenols with an aromatic aldehyde compound such as benzaldehyde or salicylaldehyde in the presence of an acid catalyst. In the above general formula (1), the phenol resin in which L is represented by the above formula (d) corresponds to a triphenylmethane type phenol resin.

[0021] The modified aralkyl type phenol resin is a modified aralkyl type phenol resin obtained by condensing or co-condensing the above-mentioned phenols with an aromatic bismethoxymethyl compound such as bis(methoxymethyl)benzene or bis(methoxymethyl)biphenyl, or an aromatic bishalogenomethyl compound such as bis(chloromethyl)benzene or bis(chloromethyl)biphenyl, and an aliphatic aldehyde compound such as formaldehyde, acetaldehyde, or propionaldehyde, in the presence or absence of an acidic catalyst. In the above general formula (1), the phenol resins in which L is represented by the above formulas (a), (b) and (c) correspond to modified aralkyl-type phenol resins.

[0022] Examples of the alkyl group represented by R in the above general formula (1) include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, and an octyl group.

[0023] Examples of the aryl group represented by R in the above general formula (1) include a phenyl group, a tolyl group, a xylyl group, and a naphthyl group, and these groups may have a hydroxyl group as a substituent.

[0024] Examples of the arylalkyl group represented by R in the above general formula (1) include a benzyl group, a phenethyl group, a 1-phenylethyl group, a 2-phenylpropyl group, and a diphenylmethyl group. These groups may have a hydroxyl group as a substituent, and specific examples include groups represented by the following formulae (e) and (f).

[0025] [ka]

[0026] The phenolic resin used in the phenolic resin composition of the present invention is preferably an aralkyl-type phenolic resin or a modified aralkyl-type phenolic resin, and more preferably a biphenylaralkyl-type phenolic resin, from the viewpoint of easily adjusting the residual carbon ratio to the above-mentioned range and from the viewpoint of achieving both good flame retardancy and tracking resistance in the obtained epoxy resin cured product.

[0027] The biphenylaralkyl type phenol resin is a compound in which a biphenylaralkyl skeleton is introduced into an aralkyl type phenol resin, and is particularly preferably one represented by the following general formula (2).

[0028] [ka] (In the formula, p, q, r, and n are the same as in the above general formula (1).)

[0029] In the present invention, a phenol resin is preferred in which p, q, and r in general formula (2) each independently represent an integer of 0 or 1, at least one of p, q, and r is 1, and n is an integer of 0 to 15. In this case, it is preferred that the ratio (molar ratio) of the number of moles of a benzene ring where p, q, or r is 1, i.e., a benzene ring having two bonded hydroxyl groups (dihydric phenol such as resorcin) to the number of moles of a benzene ring where p, q, or r is 0, i.e., a benzene ring having one bonded hydroxyl group (monohydric phenol) is (number of moles of benzene ring having two bonded hydroxyl groups) / (number of moles of benzene ring having one bonded hydroxyl group)=1 to 3. Moreover, a phenol resin in which p, q and r in the general formula (3) are all 0 and n is an integer of 0 to 15 is also preferred. Commercially available biphenylaralkyl phenolic resins include, for example, MEHC-7851 series and MEHC-7403 series manufactured by Meiwa Kasei.

[0030] The weight average molecular weight (Mw) of the phenolic resin is preferably 800 to 3,000, more preferably 900 to 2,500, and even more preferably 1,000 to 2,000. When the weight average molecular weight (Mw) of the phenolic resin is within the above range, problems in handling such as blocking are unlikely to occur when the phenolic resin composition or epoxy resin composition is prepared, and the epoxy resin composition has good handleability in kneading with inorganic fillers and the like. The weight average molecular weight can be determined as a standard polystyrene-equivalent molecular weight by gel permeation chromatography (GPC).

[0031] The hydroxyl equivalent of the phenolic resin is preferably 100 g / eq or more, more preferably 110 g / eq or more, and even more preferably 120 g / eq or more from the viewpoint of the water resistance (water absorption) of the resulting epoxy resin cured product, and is preferably 240 g / eq or less, more preferably 230 g / eq or less, and even more preferably 220 g / eq or less from the viewpoint of the heat resistance of the resulting epoxy resin cured product. In particular, when the phenol resin is represented by the above general formula (2) and at least one of p, q, and r is 1, from the viewpoint of achieving both water resistance (water absorption) and heat resistance, the hydroxyl group equivalent is preferably 100 to 150 g / eq, more preferably 110 to 140 g / eq, and even more preferably 120 to 140 g / eq. When the phenol resin is represented by the above general formula (2) and p, q, and r are all 0, from the viewpoint of achieving both water resistance (water absorption) and heat resistance, the hydroxyl group equivalent is preferably 170 to 240 g / eq, more preferably 180 to 230 g / eq, and even more preferably 190 to 220 g / eq.

[0032] The softening point of the phenolic resin is preferably from a temperature below 25° C. (i.e., liquid state at 25° C.) to 120° C. or less, more preferably from 30 to 110° C., and even more preferably from 30 to 100° C. A softening point in the above range is preferable because, when the phenolic resin composition or epoxy resin composition is prepared, problems in handling such as blocking are unlikely to occur, and when the epoxy resin composition is prepared, handling properties in kneading with inorganic fillers and the like are good.

[0033] The melt viscosity of the phenolic resin at 150° C. is preferably 2.0 Pa s or less, more preferably 1.8 Pa s or less, and even more preferably 1.5 Pa s or less. In terms of mixability when made into a phenolic resin composition and handleability in kneading with inorganic fillers and the like when made into an epoxy resin composition, it is preferable that the lower limit of the melt viscosity at 150° C. is as low as possible.

[0034] The melamine cyanurate used in the phenolic resin composition of the present invention is an organic salt consisting of melamine and cyanuric acid, and commercially available products can be suitably used.

[0035] Melamine cyanurate is used as a flame retardant, and adding melamine cyanurate to an epoxy resin composition containing a phenolic resin and an epoxy resin improves the tracking resistance of the resulting epoxy resin cured product. The reason for this is not entirely clear, but it is presumed that melamine cyanurate has the property of decomposing and sublimating in a specific temperature range, and that when a voltage is applied, the melamine cyanurate sublimes, blocking the conductive path and suppressing the formation of carbonized conductive paths.

[0036] The properties of the melamine cyanurate used in the present invention are not particularly limited, but in order to improve the tracking resistance of the resulting epoxy resin cured product, the average particle size is preferably more than 3 μm, and more preferably 4 μm or more. In addition, from the viewpoint of the mechanical properties of the resulting epoxy resin cured product, the average particle size is preferably 5 μm or more, and more preferably 10 μm or more. In the present invention, the average particle size refers to the D 50 (median diameter).

[0037] From the viewpoints of handleability when made into a composition and performance such as flame retardancy and tracking resistance of the obtained epoxy resin cured product, the content of melamine cyanurate is preferably 5 to 100 parts by mass, more preferably 10 to 60 parts by mass, even more preferably 10 to 50 parts by mass, and particularly preferably 15 to 40 parts by mass, relative to 100 parts by mass of the phenolic resin.

[0038] A preferred embodiment of the phenolic resin composition of the present invention is a phenolic resin composition containing a biphenyl aralkyl type phenolic resin represented by the above general formula (2) and having a carbon residue rate of 20% or more and melamine cyanurate. The phenolic resin has a biphenyl skeleton, which enhances the flame retardancy of the obtained epoxy resin cured product, and the inclusion of melamine cyanurate improves tracking resistance and various other properties such as heat resistance.

[0039] A particularly preferred embodiment of the phenolic resin composition of the present invention is a phenolic resin composition which contains a biphenylaralkyl-type phenolic resin represented by the above general formula (2) and having a carbon residue rate of 20% or more and melamine cyanurate, the average particle size of the melamine cyanurate being 4 μm or more, and the content of the melamine cyanurate being 15 to 40 parts by mass relative to 100 parts by mass of the phenolic resin.

[0040] The phenolic resin composition of the present invention can be obtained by mixing the above-mentioned phenolic resin and the above-mentioned melamine cyanurate. There is no particular limitation on the mixing method, and the melamine cyanurate may be added to the phenolic resin that has been heated and melted, and then mixed, or the phenolic resin that has been ground and the melamine cyanurate may be powder-mixed. Alternatively, the epoxy resin composition can be directly obtained by mixing a phenolic resin, a melamine cyanurate, an epoxy resin and a curing accelerator described below.

[0041] The epoxy resin composition of the present invention contains the above-mentioned phenolic resin composition, an epoxy resin, and a curing accelerator. The epoxy resin may be any compound having two or more epoxy groups, and examples thereof include novolac type epoxy resins, bisphenol type epoxy resins, biphenyl type epoxy resins, triphenylmethane type epoxy resins, and phenol aralkyl type epoxy resins. Specifically, bisphenol A, bisphenol S, thiodiphenol, fluorene bisphenol, terpene diphenol, 4,4'-biphenol, 2,2'-biphenol, 3,3',5,5'-tetramethyl-[1,1'-biphenyl]-4,4'-diol, hydroquinone, resorcin, catechol, naphthalenediol, tris-(4-hydroxyphenyl)methane, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, phenols (phenol, alkyl-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, dihydroxynaphthalene, etc.), formaldehyde, acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde, o-hydroxybenzaldehyde, p-hydroxyacetophenone, o-hydroxyacetophenone, di ... Examples of the epoxy resin include, but are not limited to, solid or liquid epoxy resins such as cyclopentadiene, furfural, 4,4'-bis(chloromethyl)-1,1'-biphenyl, 4,4'-bis(methoxymethyl)-1,1'-biphenyl, polycondensates with 1,4-bis(chloromethyl)benzene or 1,4-bis(methoxymethyl)benzene, and modified products thereof, halogenated bisphenols such as tetrabromobisphenol A, and glycidyl ethers derived from alcohols, alicyclic epoxy resins, glycidylamine-based epoxy resins, glycidyl ester-based epoxy resins, and silsesquioxane-based epoxy resins (epoxy resins having a glycidyl group and / or an epoxycyclohexane structure in a siloxane structure having a chain, ring, ladder structure, or a mixed structure of at least two or more of these).

[0042] As the epoxy resin used in the present invention, from the viewpoint of obtaining an epoxy resin cured product having excellent flame retardancy, an epoxy resin having a biphenyl skeleton is preferable, and a biphenyl type epoxy resin and a phenol-biphenyl aralkyl type epoxy resin are more preferable. Examples of biphenyl-type epoxy resins include polyglycidyl ethers of polyhydric alcohols having a biphenyl structure, and examples of commercially available products include YX-4000 manufactured by Mitsubishi Chemical. Examples of phenol-biphenylaralkyl type epoxy resins include polyglycidyl ethers of biphenylaralkyl type phenol resins, and examples of commercially available products include the NC-3000 series manufactured by Nippon Kayaku Co., Ltd.

[0043] The epoxy equivalent of the epoxy resin is preferably 170 to 360 g / eq, and more preferably 190 to 340 g / eq, from the viewpoint of obtaining good heat resistance and flame retardancy when the epoxy resin is cured.

[0044] The content of the epoxy resin is preferably adjusted so that the value of hydroxyl equivalent / epoxy equivalent, which is the ratio of the hydroxyl equivalent (g / eq) of the phenolic resin to the epoxy equivalent in the epoxy resin, is in the range of 0.5 to 2.0, more preferably in the range of 0.8 to 1.2. By adjusting the value of hydroxyl equivalent / epoxy equivalent within this range, the curing reaction can be sufficiently advanced, and it is possible to effectively prevent unreacted phenolic resin or epoxy resin from remaining in the epoxy resin cured product. As a result, it is possible to obtain an epoxy resin cured product having the desired properties such as flame retardancy and tracking resistance.

[0045] Examples of the curing accelerator include imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, and 2-ethyl-4-methylimidazole; cycloamidines such as 1,8-diazabicyclo[5.4.0]undecene-7, 1,5-diazabicyclo[4.3.0]nonene-5, and 5,6-dibutylamino-1,8-diazabicyclo[5.4.0]undecene-7; tertiary amines such as 2-(dimethylaminomethyl)phenol, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; tributylphosphine, methyldiphenylphosphine, and the like. These include organic phosphines such as sphinc, triphenylphosphine, tris(4-methylphenyl)phosphine, diphenylphosphine, the addition product of triphenylphosphine and parabenzoquinone, and phenylphosphine; tetra-substituted phosphonium and tetra-substituted borates such as tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium ethyltriphenylborate, and tetrabutylphosphonium tetrabutylborate; quaternary phosphonium salts with counter anions other than borate; and tetraphenylboron salts such as 2-ethyl-4-methylimidazole tetraphenylborate and N-methylmorpholine tetraphenylborate. In the present invention, from the viewpoints of curability and moisture resistance, organic phosphines, in particular triphenylphosphine, are preferred. The content of the curing accelerator can be appropriately adjusted depending on the combination of the phenolic resin and the epoxy resin and the curing conditions such as temperature.

[0046] The epoxy resin composition may contain a flame retardant other than melamine cyanurate, for example, nitrogen-based flame retardants such as melamine and melamine phosphate, phosphorus-based flame retardants such as triphenyl phosphate, metal hydroxide-based flame retardants such as aluminum hydroxide and magnesium hydroxide, halogen-based flame retardants, antimony-based flame retardants, etc. The content of the flame retardant can be appropriately adjusted within a range that does not impair the effects of the present invention.

[0047] The epoxy resin composition may further contain an inorganic filler and a colorant, if necessary. Examples of the inorganic filler include fused silica such as fused spherical silica, crystalline silica, alumina, zinc oxide, magnesium oxide, boron nitride, aluminum nitride, silicon nitride, etc. In particular, the use of fused silica as the inorganic filler is preferred because it provides good filling properties in the epoxy resin composition and the epoxy resin cured product and can improve the fluidity of the epoxy resin composition. From the viewpoint of the fluidity of the epoxy resin composition, the average particle size of the inorganic filler is preferably 0.2 to 70 μm, and more preferably 0.5 to 20 μm. The average particle size is a volume-based median size calculated from the measured particle size distribution by a laser diffraction / scattering method, and can be measured using a commercially available device. The content of the inorganic filler in the epoxy resin composition is preferably 70% by mass or more and 95% by mass or less, and more preferably 70% by mass or more and 90% by mass or less, from the viewpoints of flame retardancy, tracking resistance, moisture resistance, kneadability, moldability, etc. If the blending ratio of the inorganic filler is below this range, the flame retardancy, tracking resistance, and water absorption rate of the epoxy resin cured product will deteriorate, and if it is above this range, the kneadability and moldability will deteriorate. By setting it within this range, it is possible to obtain an epoxy resin cured product that satisfies the moisture resistance, kneadability, and moldability, and also satisfies the desired flame retardancy, tracking resistance, and moisture resistance.

[0048] Examples of colorants include carbon black, red iron oxide, titanium oxide, phthalocyanine, and perylene black. The content of the colorant can be appropriately adjusted within a range that does not impair the effects of the present invention.

[0049] The epoxy resin composition is obtained by mixing the above components. Specifically, the components are mixed in a mixer, blender, or the like until sufficiently uniform, and then melt-mixed while being heated by a kneading machine such as a heat roll or kneader, and then cooled to room temperature. The mixture thus obtained is pulverized by a known means to produce a powdered epoxy resin composition. The epoxy resin composition may be in the form of a tablet, and preferably has a size and mass suitable for molding conditions.

[0050] A preferred embodiment of the epoxy resin composition of the present invention is an epoxy resin composition containing a biphenyl aralkyl phenolic resin represented by the above general formula (2) and having a carbon residue rate of 20% or more, melamine cyanurate, and an epoxy resin having a biphenyl skeleton. The phenolic resin and the epoxy resin have a biphenyl skeleton, which increases the flame retardancy of the resulting epoxy resin cured product, and the inclusion of melamine cyanurate improves tracking resistance and various other properties such as heat resistance.

[0051] In a preferred embodiment of the epoxy resin composition of the present invention, the epoxy resin having a biphenyl skeleton is more preferably a phenol-biphenyl aralkyl type epoxy resin represented by the following general formula (3). The epoxy resin represented by the following general formula (3) can be obtained by epoxidizing the biphenylaralkyl-type phenol resin represented by the above general formula (2) by a conventionally known method.

[0052] [ka] (In the formula, G represents a glycidyl group, s, t, and u each independently represent an integer of 0 or 1, and n represents an integer of 0 to 20.)

[0053] A particularly preferred embodiment of the epoxy resin composition of the present invention is an epoxy resin composition which contains a biphenylaralkyl-type phenolic resin represented by the general formula (2) and having a carbon residue rate of 20% or more, melamine cyanurate, and a phenol-biphenylaralkyl-type epoxy resin represented by the general formula (3), in which the average particle size of the melamine cyanurate is 4 μm or more, and the content of the melamine cyanurate is 6 to 15 parts by mass per 100 parts by mass of the total resin (the total mass of the biphenylaralkyl-type phenolic resin represented by the general formula (2) and the phenol-biphenylaralkyl-type epoxy resin represented by the general formula (3)).

[0054] The epoxy resin composition thus obtained is cured to obtain a cured epoxy resin product. The epoxy resin cured product can be obtained by curing the epoxy resin composition by a known method. The epoxy resin composition can be cured by, for example, injection molding, transfer molding, compression molding, or other heat and pressure molding.

[0055] The epoxy resin cured product is excellent in tracking resistance and flame retardancy, and further in heat resistance, moisture resistance, etc., and can therefore be suitably used as an encapsulant for encapsulating semiconductor elements. Furthermore, a semiconductor device containing the epoxy resin cured product is excellent in tracking resistance and flame retardancy, and further in heat resistance, moisture resistance, etc. EXAMPLES

[0056] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0057] The phenol resin, melamine cyanurate, epoxy resin, curing accelerator, and inorganic filler used in Examples 1 to 3 and Comparative Examples 1 to 7 are shown below.

[0058] [Phenol resin] Phenol Resin A A biphenyl aralkyl phenolic resin represented by the following general formula (A). (Hydroxyl equivalent: 134g / eq, softening point: 94℃, melt viscosity: 605mPa·s, weight average molecular weight (Mw): 1350, 550℃ residual carbon ratio (TG / DTA): 47%)

[0059] [ka] (In the formula, n is any number that satisfies the above Mw, and p', q', and r' are each independently an integer of 0 or 1, with 36% being 0 and 64% being 1.)

[0060] Phenol Resin B A triphenylmethane type phenolic resin represented by the following general formula (B). (Hydroxyl equivalent: 98g / eq, softening point: 109℃, melt viscosity: 861mPa·s, weight average molecular weight (Mw): 680, 550℃ residual carbon ratio (TG / DTA): 44%)

[0061] [ka] (In the formula, n is any number that results in the above Mw.)

[0062] Phenol Resin C A dicyclopentadiene-type phenolic resin represented by the following general formula (C). (Hydroxy group equivalent: 208g / eq, softening point: 98℃, melt viscosity: 370mPa·s, weight average molecular weight (Mw): 770, 550℃ residual carbon ratio (TG / DTA): 2%)

[0063] [ka] (In the formula, n is any number that results in the above Mw.)

[0064] [Melamine cyanurate] Melamine cyanurate (Nissan Chemical MC-4000 Average particle size (D 50 ):<14μm, Maximum particle size:<100μm, pH:4~6, Bulk density:0.2~0.5g / ml) Melamine cyanurate (Sakai Chemical Co., Ltd. MC-20S Average particle size (D 50 ):4μm, bulk specific gravity:0.33g / ml) Melamine cyanurate (Sakai Chemical Co., Ltd. MC-2010N Average particle size (D 50 ):3μm, bulk specific gravity: 0.25g / ml) Melamine cyanurate (Nissan Chemical MC-6000 Average particle size (D 50 ): <2μm, maximum particle size: <20μm, pH: 4~6, bulk specific gravity: 0.1~0.3g / ml)

[0065] [Epoxy resin] Phenol-biphenyl aralkyl type epoxy resin (Nippon Kayaku NC-3500, epoxy equivalent: 205g / eq)

[0066] [Cure accelerator] Triphenylphosphine (TPP manufactured by Hokko Chemical Industry Co., Ltd.)

[0067] [Inorganic filler] Fused silica (Denka FB-950, median diameter D10: 2 μm, D50: 24 μm, D90: 63 μm)

[0068] The properties of the phenolic resins used in Examples 1 to 3 and Comparative Examples 1 to 7 were evaluated by the following analysis and evaluation methods.

[0069] [Softening point] The softening point was measured using the following equipment: Equipment used: FP83HT Dropping Point / Softening Point Measurement System manufactured by Mettler Toledo Co., Ltd. Measurement conditions: Heating rate 2℃ / min. The measurements were performed according to the following procedure in accordance with the FP83HT manual. The molten sample is poured into a sample cup and allowed to cool and solidify. The cartridges are fitted above and below the cup filled with the sample and inserted into the furnace. The resin softens and flows down the orifice, and the temperature at which the bottom end of the resin passes through the light path is detected by a photocell as the softening point.

[0070] [Melt Viscosity] The melt viscosity at 150°C was measured using the following equipment. Equipment used: Brookfield B-type viscometer DV2T, Eiko Seiki Co., Ltd. Measurement temperature: 150℃ The measurements were carried out according to the following procedure. The temperature inside the furnace is set to 150° C., and a predetermined amount of sample is weighed into a cup. A cup containing a weighed sample is placed in a furnace and the resin is melted, and a spindle is inserted from above. The spindle is rotated and the melt viscosity is read when the displayed viscosity value stabilizes.

[0071] [Remaining coal rate] The carbon residue rate was measured using the following equipment. Equipment used: Hitachi High-Tech TG / DTA7200 Measurement temperature range: 25~550℃ Heating rate: 10℃ / min Measurement atmosphere: Nitrogen atmosphere 50ml / min Measurement method: The weight residual rate at 550°C was measured by TG / DTA analysis.

[0072] [Measurement of weight average molecular weight (Mw)] The weight average molecular weight (Mw) was determined in terms of standard polystyrene using the following equipment. Equipment used: Waters Alliance 2695 (gel permeation chromatograph) Column: SHODEX LF-804 Guard column: SHODEX KF-G Solvent: Tetrahydrofuran (THF) Detector: UV meter, wavelength 254 nm Flow rate: 1mL / min. Column oven temperature: 40℃

[0073] [Measurement of hydroxyl equivalent] The hydroxyl equivalent was determined according to JIS K0070.

[0074] [Examples 1 to 3, Comparative Examples 1 to 7] Phenol resin, melamine cyanurate, epoxy resin, curing accelerator and inorganic filler were mixed in the ratio (parts by mass) shown in Table 1, kneaded using two rolls at 80°C to 100°C, and then cooled and pulverized to obtain an epoxy resin composition containing the phenol resin and the epoxy resin. Using a 40 mm diameter tablet made from the obtained epoxy resin composition, a test piece was made in a transfer molding machine under the conditions of a mold temperature of 175°C, an injection pressure of 6.8 MPa, and a holding time of 600 seconds. The obtained test piece was post-cured at 180°C for 8 hours to obtain a cured epoxy resin. The cured epoxy resin was used to evaluate the tracking resistance index, flammability, heat resistance, and water resistance by the methods described below. The evaluation results are shown in Table 2.

[0075] [ Comparison Tracking Index (CIT) ] The measurements were carried out in accordance with JIS C 2134 using test pieces of the cured epoxy resin composition. Test piece dimensions: 19mm x 19mm x t4mm Test electrode: Platinum (tip blade 30°) Electrode arrangement: 4.0mm±0.1mm (opposing angle 60°) Electrolyte: Solution A (NH 4 Cl 0.1%±0.002%, Resistivity; 3.95Ω·m±0.05Ω·m) Test conditions: 50 drops confirmed, n=5, 100 drops confirmed, n=5 Test environment: 23℃±2℃, 50%RH±5%RH Measuring device: Tracking resistance tester HAT-112-3 (manufactured by Yamayo Testing Instruments)

[0076] [Flammability] Test pieces of the cured epoxy resin composition were used as the objects of evaluation in accordance with the UL-94 standard. Test piece size: 127mm x 13mm x 1mm

[0077] [Heat resistance (Tg)] The storage modulus of a test piece of the cured product of the epoxy resin composition was measured using the following equipment, and the glass transition temperature Tg (°C) was calculated. Equipment used: TA Instruments RSA-G2 Measurement conditions: 30℃~280℃, heating rate 3℃ / min Test piece: 35mm x 13mm x 1mm

[0078] [Water resistance (water absorption rate)] The water absorption (%) of test pieces of the cured epoxy resin composition was measured by the following method. Test piece size: diameter 50mm x thickness 3mm Test conditions: The test piece was immersed in pure water and heated at 95°C for 24 hours. The water absorption rate was calculated from the change in mass of the test piece before and after water absorption using the following formula. Water absorption rate (%)=(W 1 -W 0 ) / W 0 ×100 W 0 : Mass of test piece before water absorption (g) W 1 : Mass of test piece after water absorption (g)

[0079] [Measurement of mechanical properties (room temperature bending strength)] The measurements were carried out in accordance with JIS K 7171 using test pieces of the cured epoxy resin composition. Test piece size: 80mm x 10mm x 4mm

[0080] [Table 1]

[0081] An epoxy resin cured product using the phenolic resin composition of the present invention has an excellent balance of tracking resistance, flame retardancy, heat resistance, water resistance and mechanical properties, and can be suitably used as an electronic material that operates under high temperature and high voltage conditions, such as an in-vehicle semiconductor sealing material.

Claims

1. Represented by the following general formula (2): ２ The present invention comprises a phenolic resin having a carbon residue rate of 20% or more at 550°C as measured by TG / DTA under an atmosphere, and a melamine cyanurate having an average particle size of 4 μm or more, The content of melamine cyanurate is 19 to 40 parts by mass relative to 100 parts by mass of the phenolic resin, The phenolic resin composition is used in an epoxy resin composition containing a phenolic resin and an epoxy resin, which gives an epoxy resin cured product having a comparative tracking index of 550 V or more as measured in accordance with JIS C 2134 and a flame retardancy of V-0 in the UL-94 test. 【Chemistry 1】 (In the formula, p, q, and r each independently represent an integer of 0 or 1, and n represents an integer of 0 to 20.)

2. An epoxy resin composition comprising the phenolic resin composition according to claim 1, an epoxy resin, and a curing accelerator.

3. A cured epoxy resin product obtained by curing the epoxy resin composition according to claim 2.

4. A semiconductor device comprising the epoxy resin cured product according to claim 3.

5. A method for improving the tracking resistance of a cured product of an epoxy resin composition comprising a phenolic resin represented by the following general formula (2) and an epoxy resin, by adding 19 to 40 parts by mass of melamine cyanurate having an average particle size of 4 μm or more per 100 parts by mass of the phenolic resin: 【Chemistry 2】 (In the formula, p, q, and r each independently represent an integer of 0 or 1, and n represents an integer of 0 to 20.)

Images