JP5314911B2 - Epoxy resin composition and molded article - Google Patents

Description

  The present invention relates to an epoxy resin composition useful as an insulating material for electrical / electronic materials such as semiconductor sealing, laminates, and heat dissipation substrates with excellent reliability, and a molded article using the same.

  Conventionally, as a sealing method for electrical and electronic parts such as diodes, transistors, and integrated circuits, and semiconductor devices, for example, a sealing method using an epoxy resin, a silicon resin, or the like, or a hermetic sealing method using glass, metal, ceramic, etc. In recent years, resin sealing by transfer molding, which can be mass-produced with improved reliability and cost-effective, has been the mainstream in recent years.

  In a resin composition used for resin sealing by transfer molding, a sealing material composed of an epoxy resin and a resin composition mainly composed of a phenol resin as a curing agent is generally used.

  Epoxy resin compositions used for the purpose of protecting elements such as power devices are filled with an inorganic filler such as crystalline silica at a high density in order to cope with a large amount of heat released from the element.

  As power devices, there are ones constituted by a single chip incorporating IC technology and those made modular, and further improvements in heat dissipation and thermal expansion properties for sealing materials are desired.

  In order to meet these demands, attempts have been made to include inorganic fillers such as crystalline silica, silicon nitride, aluminum nitride, and spherical alumina powder having high thermal conductivity in order to improve thermal conductivity (patents). As Documents 1 and 2) increase the content of the inorganic filler, there is a problem in that the fluidity decreases with increasing viscosity during molding, and the moldability is impaired. Therefore, there is a limit to the method of simply increasing the content of the inorganic filler.

  From the above background, a method for improving the thermal conductivity of the composition by increasing the thermal conductivity of the matrix resin itself has been studied. For example, Patent Literature 3, Patent Literature 4 and Patent Literature 5 propose a liquid crystalline epoxy resin having a rigid mesogenic group and an epoxy resin composition using the same. However, an aromatic diamine compound is used as the curing agent used in these epoxy resin compositions, and there is a limit in increasing the filling rate of the inorganic filler, and there is also a problem in terms of electrical insulation. Further, when an aromatic diamine compound is used, the liquid crystallinity of the cured product can be confirmed, but the crystallinity of the cured product is low, which is not sufficient in terms of high thermal conductivity, low thermal expansion, low hygroscopicity, and the like. Furthermore, in order to exhibit liquid crystallinity, it is necessary to orient the molecules by applying a strong magnetic field, and there are significant restrictions in terms of equipment for wide industrial use. In addition, in the compounding system with the inorganic filler, the thermal conductivity of the inorganic filler is overwhelmingly larger than that of the matrix resin, and even if the thermal conductivity of the matrix resin itself is increased, There is a reality that it does not greatly contribute to the improvement of thermal conductivity, and a sufficient effect of improving thermal conductivity has not been obtained.

JP-A-11-147936 JP 2002-309067 A JP-A-11-323162 JP-A-2004-331811 JP-A-9-118673

  Therefore, the object of the present invention is to eliminate the above-mentioned problems, have excellent moldability, high thermal conductivity when combined with an inorganic filler, low thermal expansion, and excellent heat resistance and moisture resistance. It is to provide an epoxy resin composition that gives a product, and further to provide a molded product using the same.

  In the case of combining a specific bifunctional curing agent in which a reaction proceeds linearly with an epoxy resin having a mesogenic group, the present inventors have specific physical properties such as thermal conductivity, heat resistance, and low thermal expansion. It has been found that it has been improved and has reached the present invention.

The present invention relates to an epoxy resin composition mainly composed of an epoxy resin, a curing agent, and an inorganic filler, wherein 50 wt% or more of the epoxy resin is an epoxy resin having a mesogenic group, and 75 wt% or more of the curing agent is bifunctional. It is a phenolic compound, contains 80 to 96 wt% of an inorganic filler, and a cured molded product obtained by curing this epoxy resin composition has a melting point with an endothermic peak accompanying melting of crystals by scanning differential thermal analysis. It is an epoxy resin composition used to obtain a cured molded product having crystallinity characterized by being able to be observed in the range of 120 ° C. to 280 ° C.

（但し、Ｙはハロゲン原子、炭素数１〜８の炭化水素基または炭素数１〜８のアルコキシ基を示し、Ｘは単結合、−ＣＨ＝ＣＨ−基、−ＣＨ＝Ｃ（Ｍｅ）−基、−ＣＨ＝Ｃ（ＣＮ）−基、−Ｃ≡Ｃ−基、−ＣＨ＝Ｎ−基、−ＣＨ＝Ｎ（→Ｏ）−基、−ＣＨ＝ＣＨ−ＣＯ−基、−Ｎ＝Ｎ−基、−Ｎ＝Ｎ（→Ｏ）−基、−ＣＯＯ−基、−ＣＯＮＨ−基または−ＣＯ−基を示し、ｎは１〜３の数、ｍは０〜４の数を示す。）

Preferred examples of the epoxy resin having a mesogenic group include an epoxy resin having a bisphenylene unit represented by the following formula (1) or a naphthylene unit represented by the following formula (2). Here, as the naphthylene unit, a 1,4-naphthylene group, a 1,5-naphthylene group, a 2,6-naphthylene group, and a 2,7-naphthylene group are preferable.

(Y represents a halogen atom, a hydrocarbon group having 1 to 8 carbon atoms or an alkoxy group having 1 to 8 carbon atoms, and X represents a single bond, —CH═CH— group, —CH═C (Me) — group. , —CH═C (CN) — group, —C≡C— group, —CH═N— group, —CH═N (→ O) — group, —CH═CH—CO— group, —N═N— A group, —N═N (→ O) — group, —COO— group, —CONH— group or —CO— group, n is a number from 1 to 3, and m is a number from 0 to 4.

  Preferred examples of the bifunctional phenolic compound include phenolic compounds having a mesogenic group. Also, hydroquinone, 4,4′-dihydroxybiphenyl, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenyl ketone, 1,4-bis (4-hydroxyphenoxy) benzene, 4,4′-dihydroxydiphenylmethane, Preferable examples include at least one bifunctional phenolic compound selected from the group consisting of 4,4′-dihydroxydiphenyl sulfide, 1,5-naphthalenediol, 2,7-naphthalenediol, and 2,6-naphthalenediol.

  The epoxy resin composition of the present invention can contain an inorganic filler. In this case, the epoxy resin composition preferably contains 80 to 96 wt% of the inorganic filler. As the inorganic filler, spherical alumina is preferably exemplified, and the amount used is preferably 50 wt% or more of the inorganic filler.

  The epoxy resin composition of the present invention is suitable as an epoxy resin composition for electronic materials or sealing materials.

  Moreover, this invention is a composite material formed by impregnating a fibrous base material with said epoxy resin composition.

  Furthermore, the present invention is a cured molded product obtained by reacting the above epoxy resin composition and molding and curing it.

  The cured molded product has a thermal conductivity of 4 W / m · K or more, a melting point peak in the scanning differential thermal analysis is in the range of 120 ° C. to 280 ° C., or a resin component conversion in the scanning differential thermal analysis. It is preferable to satisfy at least one of the endothermic amounts of 10 J / g or more.

  The epoxy resin composition of the present invention is excellent in moldability and reliability, and gives a molded product excellent in high thermal conductivity, low water absorption, low thermal expansion, and high heat resistance. It is suitably applied as an insulating material for electrical and electronic materials such as, and exhibits excellent high heat dissipation and dimensional stability. The reason why such a specific effect occurs is presumed that the orientation of the resin layer is improved and the crystallinity is improved.

  Hereinafter, the present invention will be described in detail.

  The epoxy resin used in the epoxy resin composition of the present invention contains 50 wt% or more of an epoxy resin having one or more mesogenic groups in the molecule.

  Here, the mesogenic group is a divalent organic group having a rigid structure necessary for exhibiting liquid crystallinity, and examples thereof can be found in liquid crystal substances. Examples of liquid crystal substances include Liquid Crystals in Tablen II, D.C. Demes et al Eds. , VEB Deutscher Verlag fur grundstoffindustrie, Leipzig (1984). Moreover, the epoxy resin which has a mesogenic group is well-known by the said patent documents 3-5.

  As an epoxy resin having a preferred mesogenic group, an epoxy resin having a bisphenylene unit represented by the above formula (1) can be exemplified.

  In the above formula (1), Y represents a halogen atom such as F, Cl, or Br, a hydrocarbon group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms, and two Y atoms per molecule. When there are the above, they may be the same or different. These substitution positions may be the same or different at each benzene ring in one molecule, and the mesogenic group of the formula (1) is not necessarily a symmetrical structure. There is no need. X is a single bond, —CH═CH— group, —CH═C (Me) — group, —CH═C (CN) — group, —C≡C— group, —CH═N— group, —CH ═N (→ O) — group, —CH═CH—CO— group, —N═N— group, —N═N (→ O) — group, —COO— group, —CONH— group or —CO— group. Indicates. Here, when two or more Xs are contained in one molecule and X is an asymmetric group, all of the substitution positions may be the same or different. N is a number from 1 to 3, and m is a number from 0 to 4.

  Moreover, an epoxy resin having a naphthylene unit represented by the above formula (2) can be given as a preferable epoxy resin having a mesogenic group. Preferred naphthylene units are 1,4-naphthylene group, 1,5-naphthylene group, 2,6-naphthylene group and 2,7-naphthylene group.

  In the epoxy resin having a mesogen group used in the present invention, the epoxy group may be one in which an oxirane group, a glycidyl group, or a glycidyl ether group is directly bonded to the mesogen unit, or a carbon number as a flexible spacer group. An oxirane group, a glycidyl group, or a glycidyl ether group may be bonded through about 2 to 30 alkane chains or oxyalkane chains.

  Among them, an epoxy resin having a preferred mesogenic group is represented by the following formula (3), wherein X is a single bond, —CH═CH— group, —COO— group, —CONH— group or —CO— group, and Y is a hydrogen atom. Or an epoxy resin which is a methyl group and p is a number from 0 to 6, or in the following formula (4), X is a single bond, —CH═CH— group, —COO— group, —CONH— group or —CO -An epoxy resin in which Y is a hydrogen atom or a methyl group and q is a number from 1 to 18.

  Although the manufacturing method of the epoxy resin which has a mesogen group is not specifically limited, It can manufacture by making said dihydroxy body and epichlorohydrin which have said mesogen group react. This reaction can be performed in the same manner as a normal epoxidation reaction.

  For example, a dihydroxy compound having a mesogenic group is dissolved in excess epichlorohydrin and then in the presence of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide, preferably in the range of 50 to 150 ° C., preferably 60 to 100 ° C. And reacting for 1 to 10 hours. In this case, the amount of the alkali metal hydroxide used is in the range of 0.8 to 1.2 mol, preferably 0.9 to 1.0 mol, relative to 1 mol of the hydroxyl group in the dihydroxy body. Epichlorohydrin is used in an excess amount with respect to the hydroxyl group in the dihydroxy body, and is usually 1.5 to 15 moles relative to 1 mole of the hydroxyl group in the dihydroxy body. After completion of the reaction, excess epichlorohydrin is distilled off, the residue is dissolved in a solvent such as toluene, methyl isobutyl ketone, filtered, washed with water to remove inorganic salts, and then the target epoxy is removed by distilling off the solvent. A resin can be obtained.

  The epoxy resin used for the epoxy resin composition of the present invention can also be synthesized using a mixture of a dihydroxy compound having a mesogenic group and another phenolic compound having no mesogenic group. In this case, the mixing ratio of the dihydroxy compound having a mesogenic group is 50 wt% or more. Other phenolic compounds are not particularly limited and are selected from those having two or more hydroxyl groups in one molecule.

  The epoxy equivalent of the epoxy resin having a mesogenic group used in the epoxy resin composition of the present invention is usually in the range of 150 to 600, but it has a low viscosity from the viewpoint of increasing the filling rate of inorganic filler and improving fluidity. The epoxy equivalent is preferably in the range of 160 to 400.

  This epoxy resin having a mesogenic group usually has crystallinity at room temperature. The range of preferable melting | fusing point is 50 to 250 degreeC, More preferably, it is the range of 60 to 150 degreeC. If it is lower than this, blocking and the like are likely to occur, resulting in poor handling as a solid, and if it is higher than this, compatibility with a curing agent or the like, solubility in a solvent, and the like are reduced.

The purity of the epoxy resin having a mesogenic group, in particular the amount of hydrolyzable chlorine, is preferably smaller than the viewpoint of improving the reliability of the applied electronic component. Although it does not specifically limit, Preferably it is 1000 ppm or less, More preferably, it is 500 ppm or less. In addition, the hydrolyzable chlorine as used in the field of this invention means the value measured by the following method. That is, the potential difference the sample 0.5g were dissolved in dioxane 30 ml, 1N-KOH, after the added boiled under reflux for 30 minutes 10 ml, cooled to room temperature, 80% aqueous acetone 100ml was added, with 0.002 N-AgNO ₃ aqueous solution This is a value obtained by titration.

  In addition to the epoxy resin having a mesogenic group used as an essential component, the epoxy resin composition of the present invention may be used in combination with another epoxy resin having two or more epoxy groups in the molecule as an epoxy resin component. Examples include bisphenol A, bisphenol F, 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxydiphenylmethane, 4,4′-dihydroxydiphenylsulfone, 4,4′-dihydroxydiphenyl sulfide, Divalent phenols such as fluorene bisphenol, 2,2'-biphenol, resorcin, catechol, t-butylcatechol, t-butylhydroquinone, allylated bisphenol A, allylated bisphenol F, allylated phenol novolak, or phenol novolak Bisphenol A novolak, o-cresol novolak, m-cresol novolak, p-cresol novolak, xylenol novolak, poly-p-hydroxystyrene, tris- (4-hydroxyphenyl) meta 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, fluoroglycinol, pyrogallol, t-butyl pyrogallol, allylated pyrogallol, polyallylated pyrogallol, 1,2,4-benzenetriol, 2,3, There are glycidyl ethers derived from 4-trihydroxybenzophenone, phenol aralkyl resins, naphthol aralkyl resins, trivalent or higher phenols such as dicyclopentadiene resins, or halogenated bisphenols such as tetrabromobisphenol A. . These epoxy resins can be used alone or in combination of two or more. Moreover, 1 type, or 2 or more types can be used also about the epoxy resin which has a mesogenic group.

  The blending ratio of the epoxy resin having a mesogenic group used in the epoxy resin composition of the present invention is 50 wt% or more of the total epoxy resin, preferably 70 wt% or more, more preferably 90 wt% or more. Furthermore, it is desirable that the total amount of the bifunctional epoxy resin is 90 wt% or more, preferably 95 wt% or more. If it is less than this, the effect of improving physical properties such as thermal conductivity when cured is small. This is because the higher the content of the epoxy resin having a mesogenic group and the higher the content of the bifunctional epoxy resin, the higher the crystallinity as a molded product.

（但し、Ｚはメチレン基、酸素原子または硫黄原子、ｒは０〜１の数を示す。） As an epoxy resin other than an epoxy resin having a mesogenic group, a bisphenol-based epoxy resin represented by the following general formula (5) is preferable.

(However, Z represents a methylene group, an oxygen atom or a sulfur atom, and r represents a number of 0 to 1.)

  These epoxy resins can be synthesized by performing a normal epoxidation reaction using, for example, hydroquinone, 4,4′-dihydroxydiphenylmethane, 4,4′-dihydroxydiphenyl ether, and 4,4′-dihydroxydiphenyl sulfide as raw materials. Can do. You may synthesize | combine these epoxy resins using what was mixed with the dihydroxy compound which has a mesogen group in a raw material stage.

  The bifunctional phenolic compound used as a curing agent has two phenolic hydroxyl groups in one molecule. Although not particularly limited, for example, bisphenol A, bisphenol F, 4,4′-dihydroxydiphenylmethane, 4,4′-dihydroxydiphenyl ether, 1,4-bis (4-hydroxyphenoxy) benzene, 1,3-bis (4-hydroxyphenoxy) benzene, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl ketone, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxybiphenyl, 2,2'-dihydroxybiphenyl 10- (2,5-dihydroxyphenyl) -10H-9-oxa-10-phosphaphenanthrene-10-oxide, hydroquinone, resorcin, t-butylhydroquinone, 1,2-dihydroxynaphthalene, 1,3- Dihydroxynaphtha 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,6-dihydroxynaphthalene 2,7-dihydroxynaphthalene and the like. Two or more of these may be used. The bifunctional phenolic compound referred to in the present invention is preferably other than a phenol resin.

  As the bifunctional phenolic compound used as the curing agent, those having a mesogenic group are preferably used, and those having a bisphenylene unit of the above formula (1) or those having a naphthylene unit of the above formula (2) are exemplified. be able to. Specifically, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl ketone, 1,5-naphthalenediol, 2,6-naphthalenediol, and 2,7-naphthalenediol can be exemplified. In addition, those having no mesogenic group and preferred bifunctional phenolic compounds include hydroquinone, resorcin, 4,4′-dihydroxydiphenylmethane, 4,4′-dihydroxydiphenyl ether, 1,4-bis (4-hydroxyphenoxy) Mention may be made of benzene and 4,4′-dihydroxydiphenyl sulfide.

  The amount of the bifunctional phenolic compound used as the curing agent is 75 wt% or more of the total curing agent, preferably 80 wt% or more, more preferably 90 wt% or more, and even more preferably 95 wt% or more. If it is less than this, the effect of improving physical properties such as thermal conductivity when cured is small. This is because the higher the content of the bifunctional phenolic compound, the higher the crystallinity as a molded product.

  As a hardening | curing agent used with the epoxy resin composition of this invention, the other hardening agent generally known as a hardening | curing agent other than said bifunctional phenolic compound can be used in combination. Examples include amine curing agents, acid anhydride curing agents, phenolic curing agents, polymercaptan curing agents, polyaminoamide curing agents, isocyanate curing agents, block isocyanate curing agents, and the like. What is necessary is just to set the compounding quantity of these other hardening | curing agents suitably considering the kind of hardening | curing agent to mix | blend and the physical property of the heat conductive epoxy resin molded object obtained. However, it does not exceed 25 wt% of the total curing agent.

  Specific examples of the amine curing agent include aliphatic amines, polyether polyamines, alicyclic amines, aromatic amines and the like. Aliphatic amines include ethylenediamine, 1,3-diaminopropane, 1,4-diaminopropane, hexamethylenediamine, 2,5-dimethylhexamethylenediamine, trimethylhexamethylenediamine, diethylenetriamine, iminobispropylamine, bis ( Hexamethylene) triamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, N-hydroxyethylethylenediamine, tetra (hydroxyethyl) ethylenediamine and the like. Examples of polyether polyamines include triethylene glycol diamine, tetraethylene glycol diamine, diethylene glycol bis (propylamine), polyoxypropylene diamine, and polyoxypropylene triamines. Cycloaliphatic amines include isophorone diamine, metacene diamine, N-aminoethylpiperazine, bis (4-amino-3-methyldicyclohexyl) methane, bis (aminomethyl) cyclohexane, 3,9-bis (3-amino). Propyl) 2,4,8,10-tetraoxaspiro (5,5) undecane, norbornenediamine and the like. Aromatic amines include tetrachloro-p-xylenediamine, m-xylenediamine, p-xylenediamine, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, 2,4-diaminoanisole, 2, 4-toluenediamine, 2,4-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-diamino-1,2-diphenylethane, 2,4-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone , M-aminophenol, m-aminobenzylamine, benzyldimethylamine, 2-dimethylaminomethyl) phenol, triethanolamine, methylbenzylamine, α- (m-aminophenyl) ethylamine, α- (p-aminophenyl) Ethylamine, diaminodiethyl And rudimethyldiphenylmethane, α, α'-bis (4-aminophenyl) -p-diisopropylbenzene, and the like.

  Specific examples of acid anhydride curing agents include dodecenyl succinic anhydride, polyadipic acid anhydride, polyazeline acid anhydride, polysebacic acid anhydride, poly (ethyloctadecanedioic acid) anhydride, poly (phenylhexadecanedioic acid) Anhydride, Methyltetrahydrophthalic anhydride, Methylhexahydrophthalic anhydride, Hexahydrophthalic anhydride, Methylhymic anhydride, Tetrahydrophthalic anhydride, Trialkyltetrahydrophthalic anhydride, Methylcyclohexene dicarboxylic anhydride, Methylcyclohexene tetracarboxylic Acid anhydride, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol bistrimellitate, het anhydride, nadic anhydride, methyl nadic anhydride 5- (2,5 -Geo Sotetrahydro-3-furanyl) -3-methyl-3-cyclohexane-1,2-dicarboxylic anhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride Examples thereof include 1-methyl-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride.

  In the epoxy resin composition of the present invention, the mixing ratio of the epoxy resin and the curing agent is preferably in the range of 0.8 to 1.5 in terms of an equivalent ratio of the epoxy group and the functional group in the curing agent. Outside this range, unreacted epoxy groups or functional groups in the curing agent remain after curing, and the reliability of the insulating material for electronic parts is lowered.

  The epoxy resin composition of the present invention preferably contains an inorganic filler. In this case, the amount of the inorganic filler added is usually 50 to 98 wt% with respect to the epoxy resin composition, preferably 80 to 96 wt%, and more preferably 86 to 96 wt%. If it is less than this, effects such as high thermal conductivity, low thermal expansion, and high heat resistance will not be sufficiently exhibited. These effects are improved as the added amount of the inorganic filler is increased, but are not improved in accordance with the volume fraction, and are drastically improved from the point when the added amount exceeds the specific amount. These physical properties are due to the effect of controlling the higher order structure in the polymer state, and since this higher order structure is achieved mainly on the surface of the inorganic filler, a specific amount of inorganic filler is required. It is thought to be. On the other hand, when the added amount of the inorganic filler is larger than this, the viscosity is increased and the moldability is deteriorated.

  The inorganic filler is preferably spherical and is not particularly limited as long as it has a spherical shape including those having a cross section on an ellipse, but from the viewpoint of improving fluidity, it should be as close to a true sphere as possible. Is particularly preferred. Thereby, it is easy to take a close-packed structure such as a face-centered cubic structure or a hexagonal close-packed structure, and a sufficient filling amount can be obtained. When the amount is not spherical, the friction between the fillers increases as the filling amount increases, and before reaching the above upper limit, the fluidity is extremely lowered to increase the viscosity and the moldability is deteriorated.

  From the viewpoint of improving thermal conductivity, it is preferable that 50 wt% or more, preferably 80 wt% or more of the inorganic filler has a thermal conductivity of 5 W / m · K or more. As such an inorganic filler, alumina, aluminum nitride, crystalline silica and the like are suitable. Among these, spherical alumina is excellent. In addition, an amorphous inorganic filler such as fused silica or crystalline silica may be used in combination, if necessary, regardless of the shape.

  Moreover, it is preferable that the average particle diameter of an inorganic filler is 30 micrometers or less. If the average particle size is larger than this, the fluidity of the epoxy resin composition is impaired, and the strength is also lowered.

  A conventionally well-known hardening accelerator can be used for the epoxy resin composition of this invention. Examples include amines, imidazoles, organic phosphines, Lewis acids, etc., specifically 1,8-diazabicyclo (5,4,0) undecene-7, triethylenediamine, benzyldimethylamine, Tertiary amines such as ethanolamine, dimethylaminoethanol, tris (dimethylaminomethyl) phenol, imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-heptadecylimidazole, Organic phosphines such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine, phenylphosphine, tetraphenylphosphonium / tetraphenylborate, tetraphenylphosphonium / ethyltriphenyl Rate, tetra-substituted phosphonium tetra-substituted borate such as tetrabutylphosphonium-tetrabutyl borate, 2-ethyl-4-methylimidazole · tetraphenyl port rate, and the like tetraphenyl boron salts such as N- methylmorpholine-tetraphenyl port rate. As addition amount, it is the range of 0.2-10 weight part normally with respect to 100 weight part of epoxy resins. These may be used alone or in combination.

  As for the addition amount of the said hardening accelerator, 0.1-10.0 wt% is preferable with respect to the sum total of an epoxy resin and a hardening | curing agent. If it is less than 0.1 wt%, the gelation time will be delayed, resulting in a decrease in workability due to a decrease in rigidity during the heating reaction. Conversely, if it exceeds 10.0 wt%, the reaction will progress during the molding and unfilling will occur. It becomes easy.

  In the epoxy resin composition of the present invention, in addition to the above components, a mold release agent, a coupling agent, a thermoplastic oligomer, and other components that can be generally used for an epoxy resin composition are appropriately blended and used. be able to. For example, phosphorus-based flame retardants, flame retardants such as bromine compounds and antimony trioxide, and colorants such as carbon black and organic dyes can be used.

  Wax can be used as the release agent. As the wax, for example, stearic acid, montanic acid, montanic acid ester, phosphoric acid ester and the like can be used.

  As the coupling agent, for example, epoxy silane can be used. The addition amount of the coupling agent is preferably 0.1 to 2.0 wt% with respect to the epoxy resin composition. If it is less than 0.1 wt%, the resin and the base material will not be well-matched, and the moldability will be poor. Conversely, if it exceeds 2.0 wt%, the molded product will become dirty with continuous moldability. The coupling agent is used to improve the adhesion between the inorganic filler and the resin component.

  Thermoplastic oligomers include C5 and C9 petroleum resins, styrene resins, indene resins, indene / styrene copolymer resins, indene / styrene / phenol copolymer resins, indene / coumarone copolymer resins, indene / benzothiophene. Examples thereof include copolymer resins. As addition amount, it is the range of 2-30 weight part normally with respect to 100 weight part of epoxy resins. Thermoplastic oligomers are used to improve fluidity during molding of the epoxy resin composition and to improve adhesion to a substrate such as a lead frame.

  The epoxy resin composition of the present invention comprises an epoxy resin and a curing agent as essential components, and a blending component (excluding a coupling agent) containing components such as an inorganic filler is uniformly mixed by a mixer or the like, and then a coupling agent. And knead | mixing with a heating roll, a kneader, etc. can manufacture. There is no restriction | limiting in particular in the compounding order of these components except a coupling agent. Further, after kneading, the melt-kneaded material can be pulverized to be powdered or tableted.

  The epoxy resin composition of the present invention is particularly suitable as an epoxy resin composition for electronic materials because it is excellent for electronic component sealing and heat dissipation substrates.

  The epoxy resin composition of the present invention can be combined with a fibrous base material such as glass fiber to form a composite material. For example, a sheet fiber base material impregnated with an epoxy resin composition mainly composed of an epoxy resin and a curing agent in an organic solvent is impregnated and dried by heating to partially react the epoxy resin to obtain a prepreg. be able to.

  In order to obtain a cured molded product using the epoxy resin composition of the present invention, for example, a heat molding method such as transfer molding, press molding, cast molding, injection molding, extrusion molding or the like is applied. From the viewpoint, transfer molding is preferable.

  Even when the epoxy resin composition of the present invention is composed only of a bifunctional epoxy resin and a curing agent, when the epoxy resin and the curing agent are heated and reacted, the epoxy resin and the curing agent react with each other. Since this part further reacts with the epoxy group in the epoxy resin, it usually gives a three-dimensional cured product, but in some cases, by use of an organic solvent, selection of a curing accelerator type, and control of heating reaction conditions such as reaction temperature, It can be set as the thermoplastic molding substantially comprised only by the two-dimensional polymer.

  The cured molded product of the present invention preferably has crystallinity from the viewpoints of high heat resistance, low thermal expansion and high thermal conductivity. The expression of the crystallinity of the molded product can be confirmed by observing an endothermic peak accompanying melting of the crystal as a melting point by scanning differential thermal analysis. A preferred melting point is in the range of 120 ° C. to 280 ° C., more preferably in the range of 150 ° C. to 250 ° C. Moreover, the preferable thermal conductivity of the cured molded product is 4 W / m · K or more, and particularly preferably 6 W / m · K or more.

  Here, the effect of crystallinity will be briefly described. Generally, in a cured epoxy resin, a glass transition point is used as an index of heat resistance. This is because a normal epoxy resin cured product is an amorphous (glassy) molded product having no crystallinity, and the physical properties greatly change at the glass transition point. Therefore, in order to increase the heat resistance of the cured epoxy resin, that is, to increase the glass transition point, it is necessary to increase the crosslink density. On the other hand, the cured molded product of the present invention is characterized in that crystallinity is developed, but since the change in physical properties is small up to the melting point, the melting point can be used as an index of heat resistance. Since the polymer material has a melting point higher than the glass transition point, the cured molded product of the present invention can ensure high heat resistance while maintaining high flexibility due to low crosslink density. In addition, the expression of crystallinity means a high intermolecular force, which suppresses the movement of molecules, achieves low thermal expansibility, exhibits high thermal diffusivity, and improves thermal conductivity.

  Accordingly, the higher the degree of crystallinity of the cured molded product of the present invention, the better. Here, the degree of crystallization can be evaluated from the endothermic amount accompanying the melting of the crystal in the scanning differential thermal analysis. A preferable endothermic amount is 10 J / g or more per unit weight of the resin component excluding the filler. More preferably, it is 30 J / g or more, Most preferably, it is 50 J / g or more. When smaller than this, the improvement effect of the heat resistance, low thermal expansibility, and thermal conductivity as a molded product is small. The endothermic amount referred to here refers to the endothermic amount obtained by measuring with a differential scanning calorimeter using a sample accurately weighed about 10 mg in a nitrogen stream under a temperature rising rate of 10 ° C./min. . Further, the crystallized cured molded product of the present invention can be observed as a clear peak even in wide-angle X-ray diffraction. In this case, the crystallinity can be obtained by dividing the area obtained by subtracting the peak of the amorphous resin that is not crystallized from the entire peak area by the entire peak area. The desired crystallinity thus obtained is 15% or more, more preferably 30% or more, and particularly preferably 50% or more.

  The cured molded product of the present invention can be obtained by heat reaction by the above molding method. Usually, the molding temperature is 80 ° C. to 250 ° C. In order to increase the crystallinity of the molded product, It is desirable to react at a temperature lower than the melting point of the molded product. A preferable molding temperature is in the range of 100 ° C to 200 ° C, more preferably 130 ° C to 180 ° C. The preferable molding time is 30 seconds to 1 hour, more preferably 1 minute to 30 minutes. Further, after molding, the crystallinity can be further increased by post-cure. Usually, the post-cure temperature is 130 ° C. to 250 ° C., and the time is in the range of 1 hour to 20 hours. However, the temperature is 5 ° C. to 40 ° C. lower than the endothermic peak temperature in the differential thermal analysis. It is desirable to perform post-cure.

  Hereinafter, the present invention will be described more specifically with reference to examples.

Reference example 1
480.0% aqueous sodium hydroxide solution is prepared by dissolving 100.0 g of 4,4′-dihydroxybiphenyl and 50.0 g of 4,4′-dihydroxydiphenylmethane in 720 g of epichlorohydrin and 100 g of diethylene glycol dimethyl ether at 60 ° C. under reduced pressure (about 130 Torr). 127 g was added dropwise over 3 hours. During this time, the generated water was removed from the system by azeotropy with epichlorohydrin, and the distilled epichlorohydrin was returned to the system. After completion of the dropwise addition, the reaction was further continued for 1 hour, followed by dehydration. Then, epichlorohydrin was distilled off, and 950 g of methyl isobutyl ketone was added, followed by washing with water to remove the salt. Thereafter, 2.8 g of 48% sodium hydroxide was added at 85 ° C., stirred for 1 hour, and washed with 1000 mL of warm water. Then, after removing water by liquid separation, methyl isobutyl ketone was distilled off under reduced pressure to obtain 215 g of white crystalline epoxy resin.

The epoxy equivalent of this epoxy resin was 168, hydrolyzable chlorine was 340 ppm, the melting point by capillary method was 145 ° C. to 150 ° C., and the viscosity at 150 ° C. was 6 mPa · s. Of the epoxy resin obtained from 4,4′-dihydroxybiphenyl obtained by GPC measurement, 54% contained one biphenylene group and 5% contained two. Moreover, the thing containing one diphenylmethane group of the epoxy resin obtained from 4,4'-dihydroxydiphenylmethane was 24%, and the thing containing 2 was 6%. Here, hydrolyzable chlorine is obtained by dissolving 0.5 g of a sample in 30 ml of dioxane, adding 1 N-KOH, 10 ml, boiling and refluxing for 30 minutes, cooling to room temperature, and further adding 100 ml of 80% acetone water. Is a value measured by performing potentiometric titration with a 0.002N-AgNO ₃ aqueous solution. The melting point is a value obtained by a capillary method at a heating rate of 2 ° C./min. The viscosity was measured with CAP2000H manufactured by BROOKFIELD. In addition, GPC measurement was carried out using a device: Nippon Waters Co., Ltd., Model 515A, column: TSK-GEL2000 × 3 and TSK-GEL4000 × 1 (both manufactured by Tosoh Corporation), solvent: tetrahydrofuran, flow rate: ml / min, temperature; 38 ° C., detector; RI conditions were followed.

Reference example 2
100 g of 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxy-trans-stilbene is dissolved in 480 g of epichlorohydrin and 70 g of diethylene glycol dimethyl ether, and 48% water at 60 ° C. under reduced pressure (about 130 Torr). 60.8 g of an aqueous sodium oxide solution was added dropwise over 3 hours. During this time, the generated water was removed from the system by azeotropy with epichlorohydrin, and the distilled epichlorohydrin was returned to the system. After completion of the dropwise addition, the reaction was further continued for 1 hour, followed by dehydration. Then, epichlorohydrin was distilled off, 570 g of methyl isobutyl ketone was added, and then washed with water to remove the salt. Thereafter, 2.5 g of 48% sodium hydroxide was added at 85 ° C., stirred for 1 hour, and washed with 1000 mL of warm water. Thereafter, water was removed by liquid separation, and methyl isobutyl ketone was distilled off under reduced pressure to obtain 125 g of a white crystalline epoxy resin.

  The epoxy equivalent of this epoxy resin was 204, hydrolyzable chlorine was 340 ppm, the melting point by DSC method was 145 ° C., and the viscosity at 150 ° C. was 20 mPa · s. As for each component ratio calculated | required from GPC measurement of the obtained resin, the thing containing 1 stilbene group was 86%, and the thing containing 2 was 11%.

Examples 1-7, Comparative Examples 1-4
As the epoxy resin, the epoxy resin obtained in Reference Example 1 (Epoxy Resin A), the epoxy resin obtained in Reference Example 2 (Epoxy Resin B), and a biphenyl type epoxy resin (Epoxy Resin C: Japan Epoxy Resin, YL-6121 ( 1: 1 mixture of epoxidized 4,4′-dihydroxybiphenyl and epoxidized 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxybiphenyl), epoxy equivalent 183), 4, Epoxidized 4′-dihydroxydiphenyl ether (epoxy resin D: manufactured by Toto Kasei, YSLV-80DE, epoxy equivalent 178), or epoxidized 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxydiphenylmethane (Epoxy resin E: manufactured by Tohto Kasei, YSLV-80XY, epoxy equivalent 192) is used. 4,4′-dihydroxydiphenyl ether (curing agent A), 2,6-dihydroxynaphthalene (curing agent B), 4,4′-dihydroxybiphenyl (curing agent C), or phenol aralkyl resin (curing agent D: Mitsui Chemicals, XL-225-LL; OH equivalent 174, softening point 75 ° C.) is used. Triphenylphosphine is used as a curing accelerator, and spherical alumina (average particle size 12.2 μm) is used as an inorganic filler.

  After blending the components shown in Table 1 and mixing thoroughly with a mixer, the mixture kneaded for about 5 minutes with a heating roll was cooled and ground to obtain the epoxy resin compositions of Examples 1 to 7 and Comparative Examples 1 to 4, respectively. Obtained. Using this epoxy resin composition, after molding at 170 ° C. for 5 minutes, post-curing was carried out at 170 ° C. for 12 hours to obtain a molded product to obtain a cured molded product, and its physical properties were evaluated. The results are summarized in Table 1. In addition, the number of each component in Table 1 represents parts by weight.

[Evaluation]
(1) Thermal conductivity Thermal conductivity was measured by the unsteady hot wire method using an LFA447 type thermal conductivity meter manufactured by NETZSCH.
(2) Measurement of melting point and heat of fusion (DSC method)
Using a differential scanning calorimeter (Seiko Instruments DSC6200 type), the temperature was increased at a rate of 10 ° C./min.
(3) Linear expansion coefficient and glass transition temperature The linear expansion coefficient and glass transition temperature were measured at a temperature elevation rate of 10 ° C / min using a TMA120C type thermomechanical measuring device manufactured by Seiko Instruments Inc.
(3) Water absorption rate A disk having a diameter of 50 mm and a thickness of 3 mm was formed, and after post-curing, the weight change rate after absorbing for 100 hours under the conditions of 85 ° C. and relative humidity of 85% was used.

Claims (9)

In an epoxy resin composition containing an epoxy resin , a curing agent and an inorganic filler , 50 wt% or more of the epoxy resin is an epoxy resin having a mesogenic group, and 75 wt% or more of the curing agent is a bifunctional phenolic compound , inorganic The cured molded product obtained by containing 80 to 96 wt% of the filler and curing this epoxy resin composition is in the range of 120 ° C. to 280 ° C. with the endothermic peak accompanying melting of the crystal as determined by scanning differential thermal analysis. An epoxy resin composition used for obtaining a cured molded product having crystallinity, characterized in that it can be observed by: The epoxy resin composition according to claim 1, wherein the epoxy resin having a mesogenic group is an epoxy resin having a bisphenylene unit represented by the following formula (1) or a naphthylene unit represented by the following formula (2).

(Y represents a halogen atom, a hydrocarbon group having 1 to 8 carbon atoms or an alkoxy group having 1 to 8 carbon atoms, and X represents a single bond, —CH═CH— group, —CH═C (Me) — group. , —CH═C (CN) — group, —C≡C— group, —CH═N— group, —CH═N (→ O) — group, —CH═CH—CO— group, —N═N— A group, —N═N (→ O) — group, —COO— group, —CONH— group or —CO— group, n is a number from 1 to 3, and m is a number from 0 to 4.

(However, the position of the linking group is 1,4-position, 1,5-position, 2,6-position, or 2,7-position.)   The epoxy resin composition according to claim 1 or 2, wherein the bifunctional phenolic compound is a phenolic compound having a mesogenic group.   Bifunctional phenolic compounds are hydroquinone, 4,4′-dihydroxybiphenyl, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenyl ketone, 1,4-bis (4-hydroxyphenoxy) benzene, 4,4 It is at least one phenolic compound selected from the group consisting of '-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenyl sulfide, 1,5-naphthalenediol, 2,7-naphthalenediol, and 2,6-naphthalenediol. Item 3. The epoxy resin composition according to Item 1 or 2. The epoxy resin composition according to any one of claims 1 to 4 , wherein 50 wt% or more of the inorganic filler is spherical alumina . It is an epoxy resin composition for electronic materials, The epoxy resin composition in any one of Claims 1-5 characterized by the above-mentioned. A cured molded product obtained by molding and curing the epoxy resin composition according to any one of claims 1 to 5 . The cured molded article according to claim 7, which has a thermal conductivity of 4 W / m · K or more . The cured molded article according to claim 7 or 8, wherein an endothermic amount in terms of a resin component in scanning differential thermal analysis is 10 J / g or more .