JP5265461B2 - Crystalline modified epoxy resin, epoxy resin composition and crystalline cured product - Google Patents

Abstract

PURPOSE: A crystalline modified epoxy resin and an epoxy resin composition are provided to ensure excellent moldability and reliability and to form a hardening material with high thermal conductivity, low absorption, low thermal expansibility, and high thermal resistance. CONSTITUTION: A crystalline modified epoxy resin which is crystalline in a room temperature and has a melting point of 120~160 °C is obtained by reacting a mixture consisting of (a) 100.0 parts by weight of 4,4'-dihydroxybiphenyl and (b) 20~100.0 parts by weight of phenolic compound represented by chemical formula(1), with epichlorohydrin.

Description

  The present invention has excellent handleability as a solid at room temperature, which is useful for insulating materials for electrical and electronic parts such as highly reliable semiconductor sealing, laminates, and heat dissipation boards, and low viscosity during molding. The present invention relates to a crystalline modified epoxy resin, an epoxy resin composition using the same, and a crystalline cured product obtained therefrom.

  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 or a silicon resin, or a hermetic sealing method using glass, metal, ceramic, or the like has been used. In recent years, resin sealing by transfer molding, which is capable of mass production with improved reliability and cost merit, has been the mainstream.

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

  Further, as a method for mounting electronic components on a printed circuit board, a transition from a conventional pin insertion method to a surface mounting method has been progressing. In the surface mounting method, the entire package is heated to the solder temperature, so package cracking due to thermal shock has become a major problem. However, a high filling rate of inorganic fillers is an effective method for preventing package cracking. is there. In addition, an epoxy resin composition used as a sealing material for a power device or the like is required to be filled with an inorganic filler at a high density in order to cope with a large amount of heat released from the element.

  In order to satisfy the above-mentioned demand, an epoxy resin excellent in low viscosity is desired. As low-viscosity epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, and the like are generally widely used. Of these epoxy resins, those having low viscosity are liquid at room temperature and are difficult to handle. Furthermore, these epoxy resins are not sufficient in terms of heat resistance, mechanical strength, and toughness.

  From the above background, many epoxy resin compositions using a crystalline epoxy resin that is solid at room temperature have been proposed recently. Patent Document 1 proposes an epoxy resin composition for semiconductor encapsulation based on a biphenyl-based epoxy resin as an improved handling workability, heat resistance, toughness, etc., but has low water absorption and low viscosity. In terms of curability, it is not sufficient. Patent Document 2 proposes a bisphenol F type solid epoxy resin as a main agent. Bisphenol F-type epoxy resin is characterized by excellent low viscosity, but has problems in heat resistance and curability. Patent Document 3 proposes a modified epoxy resin obtained by epoxidizing a mixture of 4,4′-dihydroxybiphenyl and a polyfunctional phenolic compound, but it has a low crystallinity having a softening point of 120 ° C. or less. Alternatively, it is an amorphous resin, and the cured product does not exhibit crystallinity, and therefore has no effect of improving thermal conductivity. Similarly, Patent Document 4 proposes a modified epoxy resin obtained by epoxidizing a mixture of 4,4′-dihydroxydiphenylmethane and 4,4′-dihydroxybiphenyl. On the other hand, it is a combination of 6 times or more of 4,4′-dihydroxydiphenylmethane, which is excellent in workability at a low softening point, but has a low content of biphenyl structure, so the crystallinity of the cured product does not appear. There was no effect of improving thermal conductivity.

  In addition, attempts have been made to use crystalline silica, silicon nitride, aluminum nitride, and spherical alumina powder as a technique for improving thermal conductivity (Patent Documents 5 and 6). When it raises, the fluidity falls with the viscosity increase at the time of shaping | molding, and the problem that moldability will be impaired arises. Therefore, there is a limit to the method of simply increasing the content of the inorganic filler.

  Against this background, methods for increasing the thermal conductivity of the matrix resin itself have also been studied. For example, Patent Documents 7 and 8 propose a resin composition using a liquid crystalline resin having a rigid mesogenic group. Yes. However, these epoxy resins having a mesogenic group are a substantially single epoxy compound having a rigid structure such as a biphenyl structure and an azomethine structure and having a high crystallinity and a high melting point molecular weight distribution. There was a drawback that the workability when making the product was inferior. Furthermore, in order to efficiently orient the molecules in the cured state, it is necessary to cure by applying a strong magnetic field, and there are significant restrictions on facilities for wide use industrially. 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. And it is the improvement of the thermal conductivity of the resin that has been studied for the improvement of the thermal conductivity. In the case of a mixed system with a filler, if the filler is sufficiently present, the thermal conductivity of the filler is overwhelmingly high. Therefore, it has been generally recognized that even if the thermal conductivity of the resin is improved somewhat, the effect is small.

  Patent Document 9 discloses an epoxy resin composition that is highly filled with an inorganic filler and can obtain a molded article having excellent thermal conductivity, but the means for achieving this is an improvement of the filler. There is no attempt to improve the resin.

JP 4-7365 JP-A-6-345850 JP 11-43531 A JP 2006-45261 A JP-A-11-147936 JP 2002-309067 A JP-A-11-323162 JP-A-2004-331811 JP 2001-348488 A

  Accordingly, the object of the present invention is to solve the above-mentioned problems and to combine with a crystalline modified epoxy resin excellent in handling property as a solid at room temperature and excellent in low viscosity at a molding temperature, and an inorganic filler. It is to provide an epoxy resin composition that provides a cured product having high thermal conductivity, low thermal expansion, and excellent heat resistance and moisture resistance, and a cured product thereof.

  As a result of various studies to solve the above problems, in the case of a specific resin, when a certain amount or more of an inorganic filler is included, a phenomenon in which the thermal conductivity improvement of the resin is reflected in the final cured product is recognized. It was. Then, by reacting with a mixture of compounds having specific phenolic hydroxyl groups and epichlorohydrin, it has crystallinity at room temperature, has excellent handleability, and specifically improves the thermal conductivity as a composite material. The present invention has been found.

（但し、ｎは平均値として１〜５の数を示す。）
で表され、ｎ＝１体の含有率が５０重量％以上であり、４，４'−ジヒドロキシジフェニルメタンの含有率が５０重量％以下であるフェノール性化合物２０〜１００重量部を混合した混合物と、エピクロルヒドリンを反応させて得られ、エポキシ当量が１６０〜２００の範囲であることを特徴とする常温で結晶性を有する変性エポキシ樹脂である。 The present invention relates to (a) 100 parts by weight of 4,4′-dihydroxybiphenyl, (b) the following general formula (1),

(However, n shows the number of 1-5 as an average value.)
A mixture in which 20 to 100 parts by weight of a phenolic compound in which the content of n = 1 body is 50% by weight or more and the content of 4,4′-dihydroxydiphenylmethane is 50% by weight or less; obtained by reacting epichlorohydrin, epoxy equivalent weight of modified epoxy resin having crystallinity at room temperature, wherein the range der Rukoto of 160-200.

  Further, the present invention uses (A) an epoxy resin, (B) a curing agent, and (C) 50 wt% or more of the above-mentioned modified epoxy resin as an epoxy resin in an epoxy resin composition containing as a main component. It is an epoxy resin composition characterized by these.

The preferable aspect of the said epoxy resin composition is shown next.
1) The content of the inorganic filler is 80 to 96 wt%.
2) The curing agent is a phenolic curing agent.
3) Use at least 50 wt% of bifunctional phenolic compounds as phenolic curing agents.
4) The bifunctional phenol compound is hydroquinone, 4,4′-dihydroxybiphenyl, 4,4′-dihydroxydiphenyl ether, 1,4-bis (4-hydroxyphenoxy) benzene, 4,4′-dihydroxydiphenylmethane, 4 , 4′-dihydroxydiphenyl sulfide, 1,5-naphthalenediol, 2,7-naphthalenediol, and 2,6-naphthalenediol.
5) Use spherical alumina as inorganic filler at 50wt% or more of inorganic filler.

  Furthermore, the present invention is the above epoxy resin composition, which is an epoxy resin composition for semiconductor encapsulation.

  Moreover, this invention is a hardened | cured material obtained by hardening said epoxy resin composition, and heat conductivity is 4 W / m * K or more.

  Here, the cured product has a melting point peak in the range of 150 to 300 ° C. in the scanning differential thermal analysis, or the endothermic amount in terms of the resin component in the scanning differential thermal analysis of the cured product is 5 J / g or more. It is good.

  The crystalline modified epoxy resin and the epoxy resin composition of the present invention provide a cured product excellent in moldability and reliability, and having 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 parts such as a stopper, a laminated plate, and a heat dissipation board, and exhibits excellent high heat dissipation and dimensional stability.

The differential scanning calorimetry chart of the crystalline modified epoxy resin of this invention is shown.

  The crystalline modified epoxy resin of the present invention can be produced by reacting a mixture of 4,4'-dihydroxybiphenyl and a phenolic compound of formula (1) with epichlorohydrin. This reaction can be performed in the same manner as a normal epoxidation reaction.

  In the formula (1), n is in the range of 1 to 5 as an average value, but the content of n = 1 body is 50% by weight or more, preferably the content of n = 1 body is 80% by weight or more. From the viewpoint of reducing the viscosity, the average value of n is preferably in the range of 1 to 2. Further, n = 1 isomers include 4,4′-dihydroxydiphenylmethane, 2,4′-dihydroxydiphenylmethane, and 2,2′-dihydroxydiphenylmethane as isomers, but 4,4′-dihydroxydiphenylmethane in phenolic compounds. So that the content of slag does not exceed 50 wt%. When the content of 4,4'-dihydroxydiphenylmethane exceeds 50 wt%, the melting point of the modified epoxy resin of the present invention increases, and the handleability and moldability of the epoxy resin composition are lowered. The content of 4,4'-dihydroxydiphenylmethane is preferably in the range of 10 to 40 wt%.

  The mixing ratio of 4,4′-dihydroxybiphenyl and the phenolic compound of formula (1) is such that the phenolic compound of formula (1) is 20 to 100 parts by weight with respect to 100 parts by weight of 4,4′-dihydroxybiphenyl. Although it is a range, Preferably it is the range of 30-80 weight part. If it is smaller than this, the handling property is inferior due to the high melting point of the epoxy compound of 4,4'-dihydroxybiphenyl, and if it is larger than this, the properties such as heat resistance and thermal conductivity of the cured product are deteriorated.

  The epoxy resin of the present invention is obtained by reacting a mixture of 4,4'-dihydroxybiphenyl and a phenolic compound of the formula (1) (hereinafter referred to as a phenol mixture) and epichlorohydrin. The reaction with epichlorohydrin is, for example, by dissolving a phenol mixture in an excess amount of epichlorohydrin in a molar ratio with respect to these phenolic hydroxyl groups, and then in the presence of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide. 50-150 degreeC, Preferably, the method of making it react for 1 to 10 hours in the range of 60-100 degreeC is mentioned. 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 phenol mixture. An excess amount of epichlorohydrin is used with respect to the hydroxyl group in the phenol mixture, and is usually 1.5 to 15 mol, preferably 3 to 10 mol, per 1 mol of the hydroxyl group in the phenol mixture. 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.

  In producing the modified epoxy resin of the present invention, a small amount of 4,4'-dihydroxybiphenyl and another type of phenolic compound other than the phenolic compound of formula (1) can be mixed in the phenol mixture. However, in this case, the total amount of the different types of phenolic compounds may be 50 wt% or less of the total phenolic compounds, preferably 30 wt% or less, more preferably 10 wt% or less.

  The epoxy equivalent of the crystalline modified epoxy resin of the present invention is usually in the range of 160 to 320, but a low viscosity is preferable from the viewpoint of increasing the filling rate of the inorganic filler and improving the fluidity. Those in the range of 200 are preferred.

  The crystalline modified epoxy resin of the present invention has crystallinity at room temperature. The expression of crystallinity can be confirmed as an endothermic peak accompanying the melting of the crystal by differential scanning calorimetry. The endothermic peak in this case may be observed as a plurality of peaks or a broad peak instead of one because the crystalline modified epoxy resin of the present invention is a mixture. The melting point observed by differential scanning calorimetry is the endothermic peak derived from the modified epoxy resin derived from 4,4′-dihydroxybiphenyl and the phenolic compound of formula (1), and the endothermic peak at the lowest temperature is The endothermic peak at 120 ° C or higher, preferably 130 ° C or higher and the highest temperature is 160 ° C or lower, preferably 150 ° C or lower. If it is lower than this, it will not crystallize when cured and no increase in thermal conductivity will be observed, and if it is powdered, blocking will occur and the handleability as a solid will be reduced at room temperature. Moreover, when higher than this, there exists a problem of being inferior to the solubility with a hardening | curing agent etc. and being inferior to the moldability of a composition. Further, a lower melt viscosity at 150 ° C. is better, and is usually 0.1 Pa · s or less, preferably 0.02 Pa · s or less, more preferably 0.01 Pa · s or less.

The purity of the modified epoxy resin of the present invention, in particular the amount of hydrolyzable chlorine, is better from 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.

  The epoxy resin composition of the present invention comprises (A) an epoxy resin, (B) a curing agent, and (C) an inorganic filler as main components, and the above crystalline modified epoxy resin as an epoxy resin is 50 wt% of the epoxy resin component. Including above. That is, 50 wt% or more of the total epoxy resin is the crystalline modified epoxy resin. Advantageously, 70 wt% or more, more preferably 90 wt% or more of the total epoxy resin is the modified epoxy resin. When the use ratio of the modified epoxy resin is less than this, the cured product is not crystallized and the effect of improving the thermal conductivity is small.

  In addition to the above-mentioned crystalline modified epoxy resin used as an essential component of the present invention, the epoxy resin composition of the present invention may be combined with other ordinary epoxy resins having two or more epoxy groups in the molecule. Good. Examples include bisphenol A, 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxydiphenylmethane, 4,4′-dihydroxydiphenylsulfone, 4,4′-dihydroxydiphenyl sulfide, 4,4 '-Dihydroxydiphenyl ketone, fluorene bisphenol, 4,4'-biphenol, 3,3', 5,5'-tetramethyl-4,4'-dihydroxybiphenyl, 2,2'-biphenol, resorcin, catechol, t- Butylcatechol, hydroquinone, t-butylhydroquinone, 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,7-dihydroxy Naphthalene, 1,8-dihydride Xinaphthalene, 2,3-dihydroxynaphthalene, 2,4-dihydroxynaphthalene, 2,5-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2,8-dihydroxynaphthalene, allyl of the above dihydroxynaphthalene Divalent phenols such as fluorinated or polyallylated, allylated bisphenol A, allylated bisphenol F, allylated phenol novolak, or the like, or phenol novolak, bisphenol A novolak, o-cresol novolak, m-cresol novolak, p-cresol novolak Xylenol novolak, poly-p-hydroxystyrene, tris- (4-hydroxyphenyl) methane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, Luologlicinol, pyrogallol, t-butyl pyrogallol, allylated pyrogallol, polyallylated pyrogallol, 1,2,4-benzenetriol, 2,3,4-trihydroxybenzophenone, phenol aralkyl resin, naphthol aralkyl resin, dicyclopentadiene series Examples thereof include triglycerides such as resins and glycidyl ethers derived from halogenated bisphenols such as tetrabromobisphenol A. These epoxy resins can be used alone or in combination of two or more.

  As the curing agent used in the epoxy resin composition of the present invention, all those generally known as epoxy resin curing agents can be used, but a preferred curing agent is a phenolic curing agent. The phenolic curing agent includes a phenolic compound, and the phenolic compound includes a phenolic resin as well as a phenolic compound as a single compound.

  Specific examples of the phenolic curing agent include 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, phenol novolak, bisphenol A novolak, o-cresol novolak, m-cresol novolak, p-cle All novolak, xylenol novolak, poly-p-hydroxystyrene, hydroquinone, resorcin, catechol, t-butylcatechol, t-butylhydroquinone, fluoroglycinol, pyrogallol, t-butyl pyrogallol, allylated pyrogallol, polyallylated pyrogallol, 1,2 , 4-Benzenetriol, 2,3,4-trihydroxybenzophenone, 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene 1,7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,4-dihydroxynaphthalene, 2,5-dihydroxynaphthalene, 2, -Dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2,8-dihydroxynaphthalene, allylated product or polyallylated product of the above-mentioned dihydroxynaphthalene, allylated bisphenol A, allylated bisphenol F, allylated phenol novolak, allylated pyrogallol, etc. .

  As the curing agent, two or more curing agents may be mixed and used. A preferable curing agent contains a bifunctional phenol compound in the curing agent in an amount of 50 wt% or more, preferably 70 wt% or more. Examples of the bifunctional phenol compound in this case include 4,4′-dihydroxybiphenyl, 4,4′-dihydroxydiphenyl ether, 1,4-bis (4-hydroxyphenoxy) benzene, 4,4′-dihydroxydiphenylmethane, Phenol compounds selected from 4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenyl sulfide, 1,5-naphthalenediol, 2,7-naphthalenediol, 2,6-naphthalenediol, hydroquinone, and resorcin are preferred. Among these, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl ether, or 4,4'-dihydroxydiphenylmethane is preferable.

  As the curing agent used for the epoxy resin composition of the present invention, a curing agent generally known as a curing agent can be used in addition to the above-mentioned phenolic curing agent. 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 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.

  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.

  As for the compounding ratio of the epoxy resin and the curing agent, it is preferable that the epoxy group and the functional group in the curing agent have an equivalent ratio of 0.8 to 1.5. Outside this range, unreacted epoxy groups or functional groups in the curing agent remain even after curing, which is not preferable because the reliability with respect to the sealing function is lowered.

  The amount of the inorganic filler added to the epoxy resin composition of the present invention is 80 to 96 wt%, preferably 84 to 96 wt%, based on the epoxy resin composition (whole). If it is less than this, the effects aimed by the present invention such as high thermal conductivity, low thermal expansion and high heat resistance will not be sufficiently exhibited. These effects are better as the added amount of the inorganic filler is larger. However, the effect is not improved according to the volume fraction, but dramatically improved from a specific added 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 becomes high and the moldability deteriorates, which is not preferable.

  The inorganic filler is preferably a spherical inorganic filler. The spherical inorganic filler 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 is particularly close to a true sphere as much as possible. preferable. 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. In the case of a non-spherical shape, when the filling amount is increased, friction between the fillers is increased, 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 the thermal conductivity, it is preferable to use 50 wt% or more of an inorganic filler having a thermal conductivity of 5 W / m · K or more, and alumina, aluminum nitride, crystalline silica, etc. are preferably used. The Of these, spherical alumina is particularly preferable. In addition, an amorphous inorganic filler such as fused silica or crystalline silica may be used in combination, if necessary, regardless of the shape.

  The average particle size of the inorganic filler is preferably 30 μm 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, which is not preferable.

  In the epoxy resin composition of the present invention, a known curing accelerator can be blended. 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.

  The addition amount of the curing catalyst is preferably 0.1 to 10.0 wt% with respect to the total of the epoxy resin (including a halogen-containing epoxy resin as a flame retardant) and the 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 at the time of curing. Conversely, if it exceeds 10.0 wt%, curing proceeds during the molding and unfilling is likely to occur. Become.

  In the epoxy resin composition of the present invention, a wax can be used as a release agent generally used in an epoxy resin composition. As the wax, for example, stearic acid, montanic acid, montanic acid ester, phosphoric acid ester and the like can be used.

  In the epoxy resin composition of this invention, in order to improve the adhesive force of an inorganic filler and a resin component, the coupling agent generally used for an epoxy resin composition 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.

  In addition, thermoplastic oligomers can be added to the epoxy resin composition of the present invention from the viewpoint of improving fluidity during molding and improving adhesion to a substrate such as a lead frame. 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.

  Furthermore, what can generally be used for an epoxy resin composition can be suitably mix | blended and used for the epoxy resin composition of this invention. 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.

  The epoxy resin composition of the present invention contains an epoxy resin, a curing agent and an inorganic filler as main components. In the resin component excluding the filler, the blending ratio of the epoxy resin and the curing agent is 50 wt% or more, preferably 70 wt% or more, more preferably 80 wt% or more. In addition, the resin component except a filler means all the components used as components other than a filler after hardening.

  The epoxy resin composition of the present invention is prepared by uniformly mixing an epoxy resin, a curing agent, an inorganic filler, and other components other than the coupling agent with a mixer, and then adding a coupling agent, a heating roll, a kneader, etc. Kneaded and manufactured. There is no restriction | limiting in particular in the mixing | blending order of these components. Furthermore, after kneading, the melt-kneaded product can be pulverized to be powdered or tableted.

  The epoxy resin composition of the present invention is particularly suitable for sealing a semiconductor device.

  The cured product of the present invention can be obtained by thermally curing the epoxy resin composition. In order to obtain a cured product using the epoxy resin composition of the present invention, for example, methods such as transfer molding, press molding, cast molding, injection molding, and extrusion molding are applied, but from the viewpoint of mass productivity. Transfer molding is preferred.

  The cured product of the present invention has crystallinity from the viewpoint of high thermal conductivity. The expression of crystallinity of the cured product can be confirmed by observing an endothermic peak accompanying melting of the crystal as a melting point by scanning differential thermal analysis. The preferred melting point is in the range of 150 ° C to 300 ° C, more preferably in the range of 180 ° C to 280 ° C. Moreover, the preferable heat conductivity of hardened | cured material is 4 W / m * K or more, Most preferably, it is 5 W / m * K or more.

  The higher the degree of crystallinity of the cured product of the present invention, the better, and 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 5 J / g or more per unit weight of the resin component excluding the filler. More preferably, it is 10 J / g or more, and particularly preferably 15 J / g or more. If it is smaller than this, the effect of improving the thermal conductivity as a cured epoxy resin is small. Moreover, it is so preferable that crystallinity is high also from a viewpoint of low thermal expansion property and heat resistance improvement. In addition, the endothermic amount here refers to the endothermic amount obtained by measuring with a differential thermal analyzer under the condition of a heating rate of 10 ° C./min under a nitrogen stream using a sample that is precisely weighed about 10 mg.

  The cured epoxy resin product of the present invention can be obtained by heat curing with the above molding method. Usually, the molding temperature is 100 ° C. to 250 ° C., preferably 130 ° C. to 220 ° C., more preferably 150 ° C. to 200 ° C. The preferred curing 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, but preferably 1 hour at a temperature 5 ° C. to 60 ° C. lower than the endothermic peak temperature in the differential thermal analysis. It is desirable to perform post-cure over 24 hours from the beginning.

Hereinafter, the present invention will be described more specifically with reference to examples.
BPF is bisphenol F (produced by Honshu Chemical Co., Ltd.) with n = 1 body purity of 89 wt%. In this BPF, the average value of n in the general formula is 1.06, and the isomer composition ratio in n = 1 isomer is 33% for 4,4′-isomer, 45% for 2,4′-isomer, , 2'-body is 21%.

Example 1
150 g of 4,4′-dihydroxybiphenyl and 75 g of BPF were dissolved in 1300 g of epichlorohydrin and 130 g of diethylene glycol dimethyl ether, and 193.0 g of 48% aqueous sodium hydroxide solution was added dropwise at 60 ° C. under reduced pressure (about 130 Torr) 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 1200 g of methyl isobutyl ketone was added, followed by washing with water to remove the salt. Thereafter, 30.0 g of 20% 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 304 g (epoxy resin A) of white crystalline epoxy resin. Epoxy equivalent was 163, hydrolyzable chlorine was 360 ppm, melting point by capillary method was 142 ° C. to 148 ° C., and viscosity at 150 ° C. was 5.7 mPa · s. The peak temperature in differential scanning calorimetry was 137.6 ° C. The chart is shown in FIG.

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 by the capillary method was measured at a heating rate of 2 ° C./min. Differential scanning calorimetry was performed using a DSC6200 model manufactured by Seiko Instruments Inc. at a heating rate of 10 ° C./min. Viscosity was measured with a product manufactured by BROOKFIELD, CAP2000H, and softening point was measured by a ring and ball method according to JIS K-6911. 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 Corp.), solvent: tetrahydrofuran, flow rate: 1 ml / min, temperature; 38 ° C., detector; RI conditions were followed.

Example 2
120 g of 4,4′-dihydroxybiphenyl, 80 g of BPF, 1160 g of epichlorohydrin, 116 g of diethylene glycol dimethyl ether, 170.7 g of 48% aqueous sodium hydroxide and 27.0 g of 20% sodium hydroxide were reacted in the same manner as in Example 1 to obtain a white color. As a result, 276 g (epoxy resin B) of a crystalline epoxy resin was obtained. The epoxy equivalent was 162, hydrolyzable chlorine was 310 ppm, and the viscosity at 150 ° C. was 5.1 mPa · s. The peak temperature in differential scanning calorimetry was 128.3 ° C.

Example 3
150 g of 4,4′-dihydroxybiphenyl, phenol novolak (in general formula (1), n = 1 isomer is 56 wt%, and n = 1 isomer composition ratio is 4,4′-isomer 36%, 2,4 '-Form 39%, 2,2'-form 25%, n average value 1.65, hydroxyl group equivalent 104) 50 g, epichlorohydrin 1160 g, diethylene glycol dimethyl ether 116 g, 48% sodium hydroxide aqueous solution 171.0 g, 20% hydroxylation Sodium was reacted in the same manner as in Example 1 using 25.0 g to obtain 288 g of white crystalline epoxy resin (epoxy resin C). The epoxy equivalent was 164, the hydrolyzable chlorine was 330 ppm, and the viscosity at 150 ° C. was 7.4 mPa · s. The peak temperature in differential scanning calorimetry was 141.1 ° C.

Comparative Example 1
The reaction was carried out in the same manner as in Example 1 using 80 g of 4,4′-dihydroxybiphenyl, 120 g of BPF, 1140 g of epichlorohydrin, 114 g of diethylene glycol dimethyl ether, 188.4 g of 48% aqueous sodium hydroxide, and 31.0 g of 20% sodium hydroxide. As a result, 281 g of a crystalline epoxy resin (epoxy resin D) was obtained. The epoxy equivalent was 162, hydrolyzable chlorine was 280 ppm, and the viscosity at 150 ° C. was 4.1 mPa · s. The peak temperature in differential scanning calorimetry was 117.5 ° C.

Comparative Example 2
The reaction was conducted in the same manner as in Example 1 using 75 g of 4,4′-dihydroxybiphenyl, 150 g of BPF, 1280 g of epichlorohydrin, 128 g of diethylene glycol dimethyl ether, 168.3 g of 48% aqueous sodium hydroxide and 27.0 g of 20% sodium hydroxide, and soft. 312 g (epoxy resin E) of white crystalline epoxy resin was obtained. The epoxy equivalent was 161, hydrolyzable chlorine was 390 ppm, and the viscosity at 150 ° C. was 3.2 mPa · s. The peak temperature in differential scanning calorimetry was 106.4 ° C.

Comparative Example 3
In place of BPF, 4,4′-dihydroxydiphenylmethane (purity> 99%) was used in the same manner as in Example 1 to obtain 287 g of a white crystalline epoxy resin. Epoxy equivalent was 162, hydrolyzable chlorine was 583 ppm, and melting point by capillary method was 152 ° C. to 168 ° C. Since it is a high-melting-point compound with strong crystallinity, it did not melt at 150 ° C. and an epoxy resin composition could not be prepared.

Examples 4-9, Comparative Examples 4-7
As epoxy resin components, epoxy resins A to E obtained in Example 1, Example 2, Example 3, Comparative Example 1, and Comparative Example 2, biphenyl epoxy resin (epoxy resin F: made by Japan Epoxy Resin, YX-4000H) Epoxy equivalent 195), 4,4′-dihydroxydiphenyl ether (curing agent A), 4,4′-dihydroxydiphenylmethane (curing agent B), 4,4′-dihydroxybiphenyl (curing agent C), phenol Aralkyl resin (curing agent D: Mitsui Chemicals, XL-225-LL; OH equivalent 174, softening point 75 ° C.), curing accelerator triphenylphosphine, inorganic filler as spherical alumina (average particle size 12.2 μm) The ingredients shown in Table 1 were blended, mixed thoroughly with a mixer, then kneaded with a heating roll for about 5 minutes, cooled, and powdered Respectively Example 4-9 to give an epoxy resin composition of Comparative Example 4-7. Using this epoxy resin composition, after molding at 175 ° C. for 5 minutes, post-curing was performed at 175 ° C. for 12 hours to obtain a molded product, and the physical properties of the cured product were evaluated. The results are summarized in Table 1. In addition, the number of each compound in Table 1 represents parts by weight.

Comparative Example 8
As an epoxy resin component, an epoxy composition was prepared in the same manner as in Example 4 except that an epoxy resin (melting point: 175 ° C.) obtained by reacting epichlorohydrin with 4,4′-dihydroxybiphenyl was used, and an epoxy composition was prepared at 175 ° C. Although molding was carried out under the same conditions for 5 minutes, a molding defect occurred and a cured product could not be obtained.

[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 the glass transition temperature were measured at a heating 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 (12)

(A) with respect to 100 parts by weight of 4,4′-dihydroxybiphenyl, (b) the following general formula (1),

(However, n shows the number of 1-5 as an average value.)
A mixture in which 20 to 100 parts by weight of a phenolic compound in which the content of n = 1 body is 50% by weight or more and the content of 4,4′-dihydroxydiphenylmethane is 50% by weight or less; A crystalline modified epoxy resin obtained by reacting epichlorohydrin, having an epoxy equivalent in the range of 160 to 200, having crystallinity at room temperature and a melting point of 120 ° C to 160 ° C.
  The crystalline modified epoxy resin according to claim 1, wherein the content of n = 1 isomer of the phenolic compound represented by the general formula (1) is 80% by weight or more.   In the epoxy resin composition mainly comprising (A) an epoxy resin, (B) a curing agent, and (C) an inorganic filler, the crystalline modified epoxy resin according to claim 1 or 2 as an epoxy resin is 50 wt% or more. An epoxy resin composition characterized by being used.   The epoxy resin composition according to claim 3, wherein the content of the inorganic filler is 80 to 96 wt%.   The epoxy resin composition according to claim 3 or 4, wherein the curing agent is a phenolic curing agent.   The epoxy resin composition according to any one of claims 3 to 5, wherein a bifunctional phenol compound is used in an amount of 50 wt% or more as a curing agent.   Bifunctional phenol compounds are hydroquinone, 4,4′-dihydroxybiphenyl, 4,4′-dihydroxydiphenyl ether, 1,4-bis (4-hydroxyphenoxy) benzene, 4,4′-dihydroxydiphenylmethane, 4,4 ′. The epoxy resin composition according to claim 6, which is at least one selected from the group consisting of -dihydroxydiphenyl sulfide, 1,5-naphthalenediol, 2,7-naphthalenediol, and 2,6-naphthalenediol.   The epoxy resin composition according to any one of claims 3 to 7, wherein spherical alumina is used in an amount of 50 wt% or more as the inorganic filler.   The epoxy resin composition according to claim 3, which is an epoxy resin composition for semiconductor encapsulation.   A crystalline cured product obtained by curing the epoxy resin composition according to claim 3 and having a thermal conductivity of 4 W / m · K or more.   The crystalline cured product according to claim 10, wherein the peak of the melting point in the scanning differential thermal analysis of the cured product is in the range of 150 ° C to 300 ° C.   The crystalline cured product according to claim 11, wherein an endothermic amount in terms of a resin component in a scanning differential thermal analysis of the cured product is 5 J / g or more.

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