JP7444667B2 - Epoxy resin composition and cured product - Google Patents

Description

The present invention relates to an epoxy resin composition useful as highly reliable electronic materials such as semiconductor encapsulation, laminates, and heat dissipating substrates, and carbon fiber reinforced composite materials, and a cured product using the same.

Traditionally, electrical and electronic components such as diodes, transistors, and integrated circuits, as well as semiconductor devices, have been sealed using epoxy resin, silicone resin, etc., and hermetic sealing using glass, metal, ceramic, etc. However, in recent years, resin encapsulation by transfer molding has become mainstream, as it has improved reliability, can be mass-produced, and has cost advantages.

BACKGROUND ART In a resin composition used in a resin sealing method by transfer molding, a sealing material consisting of an epoxy resin and a resin composition containing a phenol resin as a hardening agent as a main resin component is generally used.

Epoxy resin compositions used to protect elements such as power devices are densely filled with inorganic fillers such as crystalline silica to cope with the large amount of heat emitted by the elements.

Power devices include one-chip devices that incorporate IC technology and those that are modularized, and there is a need for further improvements in heat dissipation, heat resistance, and thermal expansion properties of sealing materials. There is.

In order to meet these demands, attempts have been made to use crystalline silica, silicon nitride, aluminum nitride, and spherical alumina powder to improve thermal conductivity (Patent Documents 1 and 2); When the content is increased, the viscosity during molding increases and the fluidity decreases, causing a problem that moldability is impaired. Therefore, there are limits to the method of simply increasing the content of inorganic fillers.

From the above background, methods of improving the thermal conductivity of the composition by increasing the thermal conductivity of the matrix resin itself are also being considered. For example, Patent Document 2, Patent Document 3, and Patent Document 4 propose a liquid crystalline epoxy resin having a rigid mesogenic group and an epoxy resin composition using the same. However, only an aromatic diamine compound is used as a curing agent in these epoxy resin compositions, and there is a limit to increasing the filling rate of the inorganic filler. In addition, when curing with only an aromatic diamine compound, although the liquid crystallinity of the cured product can be confirmed, the degree of crystallinity of the cured product is low, and it is not sufficient in terms of high thermal conductivity, low thermal expansion, low hygroscopicity, etc. Ta. Patent Document 5 discloses an epoxy resin composition and a cured product using an epoxy resin having a bisphenol-based mesogenic structure and a curing agent mainly composed of a bifunctional phenolic compound. However, the melting point and heat of fusion of the crystalline cured product are not high enough, and the glass transition point is also insufficient, resulting in a lack of heat resistance as a cured product. Furthermore, low water absorption and thermal conductivity were not sufficient.

Patent Document 6 discloses a 4,4'-benzophenone-based epoxy resin, but only discloses a cured product obtained by using an acid anhydride as a curing agent, and does not have a higher-order structure that exhibits high thermal conductivity. It does not give a controlled cured product. Patent Document 7 discloses a crystalline cured product that is a combination of a 4,4'-benzophenone epoxy resin and a 4,4'-benzophenone curing agent, but crosslinking occurs due to the reaction between the two functionalities. The density did not increase and the glass transition point was not sufficient.

Japanese Patent Application Publication No. 11-147936 Japanese Patent Application Publication No. 11-323162 Japanese Patent Application Publication No. 2004-331811 Japanese Patent Application Publication No. 9-118673 JP2012-233206A Japanese Unexamined Patent Publication No. 2-202512 Re-publication 2009/123058 publication

Therefore, the object of the present invention is to provide a cured product that has excellent moldability, high thermal conductivity when combined with an inorganic filler, excellent heat resistance, and excellent thermal conductivity, low thermal expansion, and moisture resistance. It is an object of the present invention to provide an epoxy resin composition that provides the following properties, and also to provide a cured product obtained using the same.

The present inventors used a specific epoxy resin as a curing agent, and a specific bifunctional phenolic curing agent that undergoes a two-dimensional reaction, and a specific polyfunctional aromatic diamine that causes three-dimensional crosslinking. When these are combined in a specific ratio, a crystalline cured product with a high glass transition point and high melting point is obtained, and physical properties such as thermal conductivity, heat resistance, and low thermal expansion are specifically improved. They discovered this and arrived at the present invention.

（但し、ｎは０～１５の数を示す。）
で表される４，４’－ベンゾフェノン系エポキシ樹脂であり、硬化剤の５０ｗｔ％以上が二官能フェノール類と芳香族ジアミン類であり、かつ、二官能フェノール類が硬化剤の２０～８０ｗｔ％、芳香族ジアミン類が硬化剤の８０～２０ｗｔ％であるエポキシ樹脂組成物である。 That is, the present invention provides an epoxy resin composition comprising an epoxy resin and a curing agent, in which 50 wt% or more of the epoxy resin is represented by the following general formula (1),

(However, n indicates a number from 0 to 15.)
A 4,4'-benzophenone epoxy resin represented by This is an epoxy resin composition in which aromatic diamines account for 80 to 20 wt% of the curing agent.

The epoxy resin composition of the present invention may contain an inorganic filler, and in this case, the content of the inorganic filler is preferably 30 to 95 wt%. The epoxy resin composition of the present invention can be suitably used for semiconductor encapsulation, as an electronic material such as a circuit board material.

Further, the present invention is a fiber-reinforced prepreg obtained by impregnating a fiber base material with the above-mentioned epoxy resin composition and bringing it into a semi-cured state.

Furthermore, the present invention is a cured product obtained by curing the above-mentioned epoxy resin composition. This cured product preferably has crystallinity, has a melting point peak in the range of 120°C to 350°C in scanning differential thermal analysis, and has an endothermic amount of 10 J/g or more in terms of resin component.

The epoxy resin composition of the present invention provides a cured product with excellent moldability, reliability, high thermal conductivity, low water absorption, low thermal expansion, and high heat resistance, and can be used for semiconductor encapsulation, circuit laminates, heat dissipation, etc. It is suitably applied as an insulating material for electrical and electronic materials such as substrates, and exhibits excellent heat dissipation, high heat resistance, and high dimensional stability. The reason for this unique effect is that by reacting a specific epoxy resin with a specific bifunctional phenolic curing agent, it promotes the orientation of molecular chains and develops crystallinity with a high melting point. It is thought that by using an aromatic diamine compound with a specific structure as a curing agent, a crosslinking reaction occurs while maintaining the crystalline state, making it possible to give the cured product a high glass transition point.

The present invention will be explained in detail below.

The 4,4'-benzophenone epoxy resin (also referred to as benzophenone epoxy resin) represented by the above general formula (1) can be produced by reacting 4,4'-dihydroxybenzophenone and epichlorohydrin. This reaction can be carried out in the same manner as a normal epoxidation reaction. For example, after dissolving 4,4'-dihydroxybenzophenone in excess epichlorohydrin, it is heated at 50 to 150°C, preferably 60 to 100°C in the presence of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide. Examples include a method of reacting for 1 to 10 hours within a range of 1 to 10 hours. At this time, the amount of alkali metal hydroxide used is 0.8 to 1.2 mol, preferably 0.9 to 1.0 mol, per 1 mol of hydroxyl group in 4,4'-dihydroxybenzophenone. range. Epichlorohydrin is used in an excess amount relative to the hydroxyl groups in 4,4'-dihydroxybenzophenone, and is usually 1.5 to 15 moles per mole of hydroxyl groups in 4,4'-dihydroxybenzophenone. After the reaction is complete, excess epichlorohydrin is distilled off, the residue is dissolved in a solvent such as toluene or methyl isobutyl ketone, filtered, washed with water to remove inorganic salts, and then the solvent is distilled off to obtain the desired benzophenone. system epoxy resin can be obtained.

In the above general formula (1), n is a number from 0 to 15, but the value of n can be easily adjusted by changing the molar ratio of epichlorohydrin to 4,4'-dihydroxybenzophenone used during the epoxy resin synthesis reaction. can do. The value of n can be selected as appropriate depending on the application. For example, in semiconductor encapsulation applications that require a high filler filling rate, fillers with low viscosity and crystallinity are preferred, and the average value of n is preferably in the range of 0.01 to 1.0. selected. If it is larger than this, the viscosity will increase and the handling properties will deteriorate.

The benzophenone-based epoxy resin used in the present invention can be synthesized using a mixture of 4,4'-dihydroxybenzophenone and another type of phenolic compound as a raw material. In this case, the mixing ratio of 4,4'-dihydroxybenzophenone is 50 wt% or more. There are no particular restrictions on the different types of phenolic compounds to be mixed, but difunctional compounds having two hydroxyl groups in one molecule are preferred.

The epoxy resin used in the present invention contains a benzophenone epoxy resin represented by general formula (1) in an epoxy resin component of 50 wt% or more, preferably 80 wt% or more, and more preferably 90 wt% or more. The epoxy equivalent of this benzophenone-based epoxy resin is usually in the range of 160 to 20,000, but a suitable epoxy equivalent is selected as appropriate depending on the application. For example, in semiconductor encapsulation applications, inorganic fillers with low viscosity are preferred from the viewpoint of increasing the filling rate and improving fluidity, and in the general formula (1) above, epoxy equivalents with n = 0 as the main component are preferred. A range of 160 to 250 is preferred. In addition, in applications such as laminates, the number is preferably in the range of 400 to 20,000 from the viewpoint of imparting film properties and flexibility.

The form of the benzophenone epoxy resin represented by the general formula (1) is appropriately selected depending on the application. For example, in applications for semiconductor encapsulation, powders are often used, so crystalline materials that are solid at room temperature are preferred, with a desirable melting point of 80°C or higher, and a preferred melt viscosity at 150°C of 0.005. It is 0.2 Pa·s. Furthermore, in applications such as laminated materials and composite materials, there are no particular restrictions on the form of the epoxy resin because it is often used after being dissolved in a solvent.

The purity of the epoxy resin used in the present invention, particularly the amount of hydrolyzable chlorine, is preferably as low as possible from the viewpoint of improving the reliability of electronic components to which it is applied. Although not particularly limited, it is preferably 1000 ppm or less, more preferably 500 ppm or less. Note that the term "hydrolyzable chlorine" as used in the present invention refers to a value measured by the following method. That is, after dissolving 0.5 g of the sample in 30 ml of dioxane, adding 10 ml of 1N-KOH and boiling and refluxing for 30 minutes, cooling to room temperature, further adding 100 ml of 80% acetone water, and applying a potential difference using a 0.002N-AgNO ₃ aqueous solution. This is the value obtained by titration.

In addition to the benzophenone epoxy resin represented by the general formula (1) used as an essential component of the present invention, the epoxy resin composition of the present invention may contain other epoxy resins having two or more epoxy groups in the molecule. May be used together. Examples include bisphenol A, bisphenol F, 4,4'-dihydroxydiphenylmethane, 3,3',5,5'-tetramethyl-4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenylsulfone, , 4'-dihydroxydiphenyl sulfide, fluorene bisphenol, 4,4'-biphenol, 3,3',5,5'-tetramethyl-4,4'-dihydroxybiphenyl, 2,2'-biphenol, resorcin, catechol, t-Butylcatechol, t-butylhydroquinone, 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,7-dihydroxy Naphthalene, 1,8-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,4-dihydroxynaphthalene, 2,5-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2,8-dihydroxynaphthalene , dihydric phenols such as allylated or polyallylated dihydroxynaphthalene, 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)methane, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, fluoroglycinol, pyrogallol, Trivalent or higher valent resins such as t-butylpyrogallol, allylated pyrogallol, polyallylated pyrogallol, 1,2,4-benzenetriol, 2,3,4-trihydroxybenzophenone, phenol aralkyl resin, naphthol aralkyl resin, dicyclopentadiene resin, etc. and glycidyl etherified products derived from phenols or halogenated bisphenols such as tetrabromobisphenol A. These other epoxy resins can be used alone or in combination of two or more. In this case, from the viewpoint of improving thermal conductivity when made into a cured product, the total amount of bifunctional epoxy resin including the benzophenone epoxy resin of general formula (1) in the epoxy resin is preferably 80 wt% or more, More preferably, the content is 90 wt% or more.

（但し、Ｒ_１～Ｒ_３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、ｍは０～５の数、Ｘは単結合、メチレン基、酸素原子、スルホン基、硫黄原子を示す。） A particularly preferred epoxy resin other than the benzophenone epoxy resin is a bisphenol epoxy resin represented by the following general formula (2).

(However, R ₁ to R ₃ represent a halogen atom, a hydrocarbon group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms, m is a number from 0 to 5, and X is a single bond or a methylene group. , indicates an oxygen atom, a sulfone group, and a sulfur atom.)

The above bisphenol-based epoxy resin includes 4,4'-dihydroxybiphenyl, 3,3',5,5'-tetramethyl-4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenylmethane, 3,3',5 , 5'-tetramethyl-4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenyl ether, and 4,4'-dihydroxydiphenyl sulfide as raw materials and can be synthesized by carrying out a conventional epoxidation reaction. These epoxy resins can be synthesized using a raw material mixed with 4,4'-dihydroxybenzophenone. Among these, particularly preferred are epoxy resins synthesized from 4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenylmethane, and 4,4'-dihydroxydiphenyl ether, which are crystalline epoxy resins with excellent handling properties. In addition to providing a resin, it is also possible to provide a molded product with excellent thermal conductivity.

The difunctional phenol used as a curing agent in the present invention is a curing agent that reacts two-dimensionally with the epoxy resin. Specifically, hydroquinone, 2,5-dimethylhydroquinone, 2,3,5-trimethylhydroquinone, 4,4'-dihydroxybiphenyl, 3,3',5,5'-tetramethyl-4,4'-dihydroxybiphenyl , 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenyl sulfide, 1,4-bis(4-hydroxyphenoxy)benzene, 1,3-bis(4-hydroxyphenoxy) Examples include benzene, dihydroxydiphenylmethanes, naphthalene diols, etc., but in order to improve the crystallinity of the cured product, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenylketone, 4, 4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl ether and 4,4'-dihydroxydiphenylmethane are preferred.

The aromatic diamine used as a curing agent in the present invention is a polyfunctional curing agent that causes a three-dimensional crosslinking reaction with an epoxy resin. For example, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone, 4,4'-diaminobenzophenone, 1,3-bis(4-aminophenoxy)benzene, bis[ 4-(4-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,4-bis(4-aminophenoxy)benzene, 4,4'-diaminodiphenyl Examples include amide, 3,3'-dimethoxy-4,4'-diaminodiphenylamide, and 1,5-diaminonaphthalene. As the aromatic diamine used in the present invention, at least one aromatic diamine selected from the group consisting of these is preferably used.

Crystallization of the cured product progresses more easily when the interaction between molecules such as hydrogen bonds is large. Preferred aromatic diamines include 4,4'-diaminodiphenylsulfone and bis[4-(4 -aminophenoxy)phenyl]sulfone, 4,4'-diaminobenzophenone, and 4,4'-diaminodiphenylamide, particularly preferred are 4,4'-diaminodiphenylsulfone and 4,4'-diaminobenzophenone. be.

The total amount of the difunctional phenols and aromatic diamines used as a curing agent in the present invention is 50 wt% or more of the curing agent component from the viewpoint of improving thermal conductivity when a cured product is formed. The proportion of difunctional phenols in the curing agent is 20 to 80 wt%, preferably 20 to 70 wt%, more preferably 20 to 60 wt%. The proportion of aromatic diamines is 80 to 20 wt% of the curing agent, but from the viewpoint of heat resistance, the proportion of aromatic diamines is preferably 30 to 80 wt%, more preferably 40 to 80 wt%.

Furthermore, as the curing agent used in the epoxy resin composition of the present invention, in addition to the above-mentioned bifunctional phenols and aromatic diamines, other curing agents that are generally known as curing agents may be used in combination. can. Examples include amine curing agents, acid anhydride curing agents, phenol curing agents, polymercaptan curing agents, polyaminoamide curing agents, isocyanate curing agents, and blocked isocyanate curing agents. The amount of these curing agents to be blended may be appropriately set in consideration of the type of curing agent to be blended and the physical properties of the resulting thermally conductive epoxy resin molded body.

In the epoxy resin composition of the present invention, the blending ratio of the epoxy resin and the curing agent is in the range of 0.8 to 1.5 in equivalent ratio of the epoxy group to the functional group in the curing agent. Outside this range, unreacted epoxy groups or functional groups in the curing agent remain even after curing, resulting in decreased reliability as an electrical insulating material, which is not preferred.

The epoxy resin composition of the present invention may contain an appropriate amount of an inorganic filler in order to improve physical properties such as thermal conductivity of the cured epoxy resin. Examples of the inorganic filler include metals, metal oxides, metal nitrides, metal carbides, metal hydroxides, carbon materials, and the like. Metals include silver, copper, gold, platinum, zircon, etc. Metal oxides include silica, aluminum oxide, magnesium oxide, titanium oxide, tungsten trioxide, etc. Metal nitrides include boron nitride, aluminum nitride, silicon nitride, etc. Metal carbides include silicon carbide, metal hydroxides include aluminum hydroxide and magnesium hydroxide, carbon materials include carbon fiber, graphitized carbon fiber, natural graphite, artificial graphite, spherical graphite particles, and mesocarbon microbeads. , whisker-like carbon, microcoiled carbon, nanocoiled carbon, carbon nanotubes, carbon nanohorns, and the like. The shape of the inorganic filler may be crushed, spherical, whisker, or fibrous. These inorganic fillers may be blended alone or in combination of two or more.

The amount of the inorganic filler added is 30 to 95 wt%, preferably 50 to 95 wt%, based on the epoxy resin composition. If the amount is less than this, effects such as high thermal conductivity, low thermal expansion, and high heat resistance will not be fully exhibited. These effects are better as the amount of inorganic filler added increases, but they do not improve depending on the volume (weight) fraction thereof, but improve dramatically from a specific amount added. These physical properties are due to the effect of controlling the higher-order structure of the resin component in the polymer state, and this higher-order structure is mainly achieved on the surface of the inorganic filler. This is considered to require the following. On the other hand, if the amount of the inorganic filler added is larger than this, the viscosity will increase and the moldability will deteriorate, which is not preferable.

The inorganic filler is preferably spherical, and is not particularly limited as long as it is spherical, including those with an elliptical cross section, but from the perspective of improving fluidity, it should be as close to a true sphere as possible. is particularly preferred. Thereby, it is easy to form a close-packed structure such as a face-centered cubic structure or a hexagonal close-packed structure, and a sufficient amount of packing can be obtained. If the filler is not spherical, friction between the fillers will increase as the filling amount increases, and before the above upper limit is reached, the fluidity will be extremely reduced, the viscosity will increase, and the moldability will deteriorate, which is not preferable.

From the viewpoint of improving thermal conductivity, it is preferable to use 50 wt% or more of inorganic fillers with a thermal conductivity of 5 W/m K or more, and alumina, aluminum nitride, crystalline silica, etc. are preferable. used for. Particularly preferred among these is spherical alumina. In addition, an amorphous inorganic filler such as fused silica, crystalline silica, etc. 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 will be impaired and the strength will also be reduced, which is not preferable.

Further, the inorganic filler may be a fibrous base material such as glass fiber or carbon fiber, or a combination of a fibrous base material and a particulate inorganic filler. When compounding the epoxy resin composition of the present invention with a fibrous base material, the fibrous base material (woven fabric or non-woven fabric) in the form of a sheet is impregnated as a varnish using a solvent and dried. It can be a prepreg in a cured state. It is also possible to impregnate a sheet-like fiber base material with an epoxy resin composition obtained by heating a solution of the epoxy resin composition to cause a partial curing reaction, and then heat-drying the epoxy resin composition.
Solvents in this case include aromatic solvents such as benzene, toluene, xylene, and chlorobenzene, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, aliphatic hydrocarbon solvents such as hexane, heptane, and methyl cyclohexane, and ethanol. , alcohol solvents such as isopropanol, butanol, and ethylene glycol; ether solvents such as diethyl ether, dioxane, tetrahydrofuran, and diethylene glycol dimethyl ether; and N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, and N-methylpyrrolidone. Polar solvents can be used.

The prepreg created in this way can be laminated with metal base materials such as copper foil, aluminum foil, and stainless steel foil, and polymer base materials such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, liquid crystal polymer, polyamide, polyimide, and Teflon. can do.

Conventionally known curing accelerators can be used in the epoxy resin composition of the present 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, and tris(dimethylaminomethyl)phenol; imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, and 2-heptadecylimidazole; Organic phosphines such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine, phenylphosphine, tetraphenylphosphonium/tetraphenylborate, tetraphenylphosphonium/ethyltriphenylborate, tetrabutylphosphonium/tetrabutylborate, etc. Examples include tetraphenylboron salts such as substituted phosphonium/tetra-substituted borate, 2-ethyl-4-methylimidazole/tetraphenylporate, and N-methylmorpholine/tetraphenylporate. These may be used alone or in combination.

The amount of curing accelerator added is usually in the range of 0.2 to 10 parts by weight per 100 parts by weight of the epoxy resin. If the amount added is too small, moldability tends to be poor, while if it is too large, curing progresses during the molding process, making it more likely that the inorganic filler will not be filled.

In the epoxy resin composition of the present invention, wax can be used as a mold release agent commonly used in epoxy resin compositions. As the wax, for example, stearic acid, montanic acid, montanic acid ester, phosphoric acid ester, etc. can be used.

In the epoxy resin composition of the present invention, a coupling agent commonly used in epoxy resin compositions can be used in order to improve the adhesive strength between the inorganic filler and the resin component. As a coupling agent, for example, epoxysilane can be used. The amount of the coupling agent added is preferably 0.1 to 2.0% by mass based on the epoxy resin composition. If it is less than 0.1% by mass, the resin and the base material will not fit well, resulting in poor moldability, and if it exceeds 2.0% by mass, contamination of the molded product will occur during continuous moldability.

Further, 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 base material 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, and indene-benzothiophene. Examples include copolymer resins. The amount added is usually in the range of 2 to 30 parts by weight per 100 parts by weight of the epoxy resin.

Furthermore, the epoxy resin composition of the present invention can be used by appropriately blending materials that can be generally used in epoxy resin compositions. For example, flame retardants such as phosphorus-based flame retardants, 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 can be prepared by uniformly mixing the epoxy resin, curing agent, inorganic filler, and other components other than the coupling agent using a mixer, etc., then adding the coupling agent, and then using a heating roll, kneader, etc. Manufactured by kneading. There is no particular restriction on the order of blending these components. Furthermore, after kneading, the melt-kneaded product can be pulverized to form a powder or tablet.

The epoxy resin composition of the present invention is useful as an electrically insulating material, and is particularly suitable for use in sealing semiconductor devices.

In order to obtain a molded article using the epoxy resin composition of the present invention, methods such as transfer molding, press molding, cast molding, injection molding, and extrusion molding are applied, but from the viewpoint of mass production. , transfer molding is preferred. During this molding, heating is performed and curing (polymerization) occurs. Therefore, since the obtained molded product is a molded product of polymerized resin, it is also called a cured molded product.

The cured product of the present invention preferably has crystallinity from the viewpoint of high heat resistance, low thermal expansion, and high thermal conductivity. The expression of crystallinity in a molded product can be confirmed by observing an endothermic peak associated with melting of crystals as a melting point by scanning differential thermal analysis. The preferred melting point is in the range of 120°C to 350°C, more preferably in the range of 180°C to 320°C, particularly preferably in the range of 200°C to 300°C.

The higher the degree of crystallinity of the cured product of the present invention, the better. Here, the degree of crystallization can be evaluated from the amount of heat absorbed due to melting of the crystals in scanning differential thermal analysis. A preferable heat absorption amount is 10 J/g or more per unit weight of the resin component excluding the filler. More preferably it is 20 J/g or more, particularly preferably 30 J/g or more. If it is smaller than this, the effect of improving the heat resistance, low thermal expansion property, and thermal conductivity of the molded product will be small. The endothermic amount referred to here is the integral of the endothermic peak obtained by measuring with a differential scanning calorimeter using a precisely weighed sample of approximately 10 mg under a nitrogen stream at a heating rate of 10°C/min. refers to a value. Further, the crystallized cured molded product of the present invention can be observed as a clear peak in wide-angle X-ray diffraction. In this case, the degree of crystallinity can be determined by dividing the area obtained by subtracting the peak of the non-crystallized amorphous resin from the total peak area by the total peak area. The desired degree of crystallinity determined in this manner is 15% or more, more preferably 30% or more, particularly preferably 50% or more.

The cured product of the present invention can be obtained by heat molding using the above molding method, and the molding temperature is usually 80°C to 250°C, but in order to increase the crystallinity of the molded product, It is desirable to mold at a temperature lower than the melting point of the cured molded product. Preferred molding temperatures range from 100°C to 220°C, more preferably from 150°C to 200°C. Moreover, the preferable molding time is from 30 seconds to 1 hour, and more preferably from 1 minute to 30 minutes. Furthermore, after molding, the degree of crystallinity can be further increased by post-curing. 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 for 1 hour at a temperature 5°C to 40°C lower than the endothermic peak temperature in differential thermal analysis. It is desirable to perform post-cure for 24 hours.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Reference example 1
1070 g of 4,4'-dihydroxybenzophenone was dissolved in 6500 g of epichlorohydrin, and 808 g of a 48% aqueous sodium hydroxide solution was added dropwise at 60° C. under reduced pressure (about 130 Torr) over 4 hours. During this time, the produced 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 continued for an additional hour, and after dehydration, epichlorohydrin was distilled off, 3500 g of methyl isobutyl ketone was added, and the salt was removed by washing with water. Thereafter, 100 g of 20% sodium hydroxide was added at 80° C., stirred for 2 hours, 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 1460 g of a pale yellow crystalline epoxy resin (epoxy resin A).

The melting point of epoxy resin A by the capillary method was 128°C to 131°C, and the viscosity at 150°C was 11.6 mPa·s. The epoxy equivalent is 179, the hydrolyzable chlorine is 270 ppm, and the ratio of each component in general formula (1) determined by GPC measurement of the obtained resin is 91.0% for n = 0 and 8 for n = 1. It was .2%. Here, hydrolyzable chlorine is obtained by dissolving 0.5 g of a sample in 30 ml of dioxane, adding 10 ml of 1N-KOH, boiling and refluxing for 30 minutes, cooling to room temperature, and then adding 100 ml of 80% acetone water. is the value measured by potentiometric titration with a 0.002N-AgNO ₃ aqueous solution. Further, the melting point is a value obtained by a capillary method at a heating rate of 2° C./min. The viscosity was measured using CAP2000H manufactured by BROOKFIELD, and the softening point was measured using the ring and ball method according to JIS K-6911. In addition, the GPC measurement was performed using an apparatus: HLC-8320 model manufactured by Tosoh Corporation, columns: TSKgel SuperHZ2500 x 2, TSKgel SuperHZ2000 x 2 (all manufactured by Tosoh Corporation), solvent: tetrahydrofuran, flow rate: 0 The following conditions were followed: 35 ml/min, temperature: 40°C, detector: RI.

Examples 1 to 7, Comparative Examples 1 to 7
As the epoxy resin component, the epoxy resin of Reference Example 1 (epoxy resin A), the epoxidized product of 4,4'-dihydroxydiphenyl ether (epoxy resin B: manufactured by Nippon Steel Chemical & Materials Co., Ltd., YSLV-80DE, epoxy equivalent: 174) Or, using biphenyl-based epoxy resin (Epoxy resin C: manufactured by Mitsubishi Chemical, YX-4000H, epoxy equivalent: 195), 4,4'-dihydroxybenzophenone (phenol A), 4,4'-dihydroxybenzophenone (phenol A), 4,4'-difunctional phenol as a curing agent, '-Dihydroxydiphenyl ether (phenol B), aromatic diamines such as 4,4'-diaminosulfone (diamine A), 4,4'-diaminodiphenylbenzophenone (diamine B), and 4,4'-diaminodiphenyl ether (diamine C). used. Further, triphenylphosphine was used as a curing accelerator, and spherical alumina (average particle size 12.2 μm) was used as an inorganic filler. The ingredients shown in Table 1 were blended, thoroughly mixed with a mixer, then kneaded with a heating roll for about 5 minutes, cooled, and pulverized to produce the epoxy resin compositions of Examples 1 to 7 and Comparative Examples 1 to 7, respectively. Obtained.
This epoxy resin composition was molded at 160°C for 8 minutes, post-cured at 160°C for 5 hours, and various physical properties of the cured molded product were evaluated. In addition, in terms of moldability, mold releasability, surface smoothness, etc., none of the compositions had any problems.

The results are summarized in Table 1. Note that the numbers for each formulation in Table 1 represent parts by weight. Moreover, the evaluation was performed as follows.

[evaluation]
(1) Thermal conductivity The thermal conductivity was measured by an unsteady hot wire method using a NETZSCH model LFA447 thermal conductivity meter.
(2) Measurement of melting point and heat of fusion (DSC method)
Measurement was performed using a differential scanning calorimeter (DSC7020 model manufactured by Hitachi High-Tech Science Co., Ltd.) at a temperature increase rate of 10° C./min. The endothermic peak temperature was defined as the melting point, and the integral value of the endothermic peak was defined as the heat of fusion.
(3) Coefficient of Linear Expansion, Glass Transition Temperature The coefficient of linear expansion and glass transition temperature were measured at a heating rate of 10° C./min using a TMA7100 thermomechanical measuring device manufactured by Hitachi High-Tech Science Co., Ltd.
(4) Water absorption rate The epoxy resin composition was molded into a disc with a diameter of 50 mm and a thickness of 3 mm at 170°C for 5 minutes, and after post-curing, it was allowed to absorb moisture for 100 hours at 85°C and 85% relative humidity. The weight change rate was taken as the subsequent weight change rate.

Claims (11)

In an epoxy resin composition consisting of an epoxy resin and a curing agent, 50 wt% or more of the epoxy resin is represented by the following general formula (1),

(However, n indicates a number from 0 to 15.)
A 4,4'-benzophenone epoxy resin represented by An epoxy resin composition characterized in that aromatic diamines account for 80 to 20 wt% of the curing agent. At least one difunctional phenol selected from 4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxybenzophenone, and 4,4'-dihydroxydiphenyl sulfone The epoxy resin composition according to claim 1, which is a type of phenolic compound. A claim in which the aromatic diamine is at least one aromatic diamine selected from 4,4'-diaminodiphenylsulfone, 4,4'-diaminobenzophenone, and bis[4-(4-aminophenoxy)phenyl]sulfone. The epoxy resin composition according to item 1 or 2. The epoxy resin composition according to any one of claims 1 to 3, wherein the aromatic diamine is 30 to 80 wt% of the curing agent. The epoxy resin composition according to any one of claims 1 to 4, containing 30 to 95 wt% of an inorganic filler. The epoxy resin composition according to any one of claims 1 to 5, which is used as an electronic material. A fiber-reinforced prepreg obtained by impregnating a fiber base material with the epoxy resin composition according to any one of claims 1 to 5 and bringing it into a semi-cured state. An epoxy resin cured product obtained by curing the epoxy resin composition or prepreg according to any one of claims 1 to 7. The cured epoxy resin product according to claim 8, wherein the cured product has crystallinity. The cured epoxy resin product according to claim 9, which has a melting point peak in the range of 120°C to 350°C in differential scanning calorimetry. The cured epoxy resin product according to claim 9 or 10, wherein the heat of fusion in differential scanning calorimetry is 10j/g or more in terms of resin excluding filler.