WO2009123058A1

WO2009123058A1 - Epoxy resin composition and molded object

Info

Publication number: WO2009123058A1
Application number: PCT/JP2009/056310
Authority: WO
Inventors: 梶　正史; 大神　浩一郎; 智美福永
Original assignee: 新日鐵化学株式会社
Priority date: 2008-03-31
Filing date: 2009-03-27
Publication date: 2009-10-08
Also published as: JP5312447B2; CN101970526A; KR20110008048A; JPWO2009123058A1; TWI494341B; KR101507933B1; CN101970526B; TW201002752A

Abstract

An epoxy resin composition having excellent moldability is provided. When combined with an inorganic filler, the epoxy resin composition gives a cured object which has a high thermal conductivity and low thermal expansion and is excellent in heat resistance and moisture resistance. The epoxy resin composition comprises an epoxy resin (A) and a hardener (B), wherein at least 50 wt.% of the epoxy resin is accounted for by a 4,4'-benzophenone epoxy resin and at least 50 wt.% of the hardener is accounted for by a 4,4'-benzophenone phenolic resin. In the composition, the ratio of the epoxy groups of the epoxy resin to the functional groups of the hardener is in the range of 0.8-1.5 by equivalent. This epoxy resin composition can contain 50-95 wt.% inorganic filler and is suitable for use in semiconductor encapsulation.

Description

Epoxy resin composition and molded article

The present invention relates to an epoxy resin composition useful for insulating materials for electrical and electronic parts such as semiconductor sealing, laminates, and heat dissipation boards having 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 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 can be mass-produced with improved reliability and cost-effective, has been the mainstream in recent years.

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. .

Currently, an epoxy resin composition used for the purpose of protecting elements such as power devices is 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 elements.

Furthermore, in recent years, power devices include one-chip devices incorporating IC technology and those made modular, and further improvements in heat dissipation and thermal expansion properties for sealing materials are desired. ing.

In order to meet these requirements, 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). Increasing the content causes a problem that the fluidity decreases as the viscosity increases 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 of increasing the thermal conductivity of the matrix resin itself has also been studied. For example, Patent Document 3 and Patent Document 4 propose a resin composition using a liquid crystalline resin having a rigid mesogenic group. Has been. However, since these epoxy resins having a mesogenic group are highly crystalline and high melting point epoxy compounds having rigid structures such as a biphenyl structure and an azomethine structure, they have a disadvantage that they are inferior in handleability when making an epoxy resin composition. there were. Furthermore, in order to efficiently orient the molecules in the cured state, special operations such as curing by applying a strong magnetic field are necessary, and there are significant equipment restrictions 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 the thermal conductivity 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.

Patent Document 5 discloses a 4,4′-benzophenone type epoxy resin, but only a cured product obtained using an acid anhydride as a curing agent is disclosed as an example, and exhibits high thermal conductivity. It does not give a controlled cured product of higher order structure.

Japanese Patent Laid-Open No. 11-147936 JP 2002-309067 A JP-A-11-323162 JP 2004-331811 A JP-A-2-202512

Therefore, the object of the present invention is to cure the above-mentioned problems, excellent moldability, high thermal conductivity when combined with an inorganic filler, low thermal expansion, 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 epoxy resin and a specific curing agent, the present inventors can obtain a molded product having a higher order structure after curing, and have high thermal conductivity, low thermal expansion, high heat resistance and high resistance. The inventors have found that the moisture resistance is specifically improved and have reached the present invention.

That is, the present invention relates to a 4,4′-benzophenone-based epoxy represented by the following general formula (1) in an epoxy resin composition containing (A) an epoxy resin and (B) a curing agent. As a resin, 50 wt% or more of the curing agent is a 4,4′-benzophenone phenolic resin represented by the following general formula (2), and the equivalent ratio of the epoxy group in the epoxy resin to the functional group in the curing agent is 0. The present invention relates to an epoxy resin composition characterized by having a range of 8 to 1.5.

(However, n represents a number from 0 to 15.)

(However, m represents a number from 0 to 15.)

The epoxy resin composition of the present invention can contain an inorganic filler. In this case, the content of the inorganic filler is preferably 50 to 95 wt%. And the epoxy resin composition of this invention is suitable as an epoxy resin composition for semiconductor sealing.

The present invention also relates to a prepreg characterized in that a sheet-like fiber base material is impregnated with the epoxy resin composition to be in a semi-cured state.

Furthermore, the present invention relates to a molded product obtained by curing and molding the above epoxy resin composition. This cured molded article preferably satisfies any one or more of the following. 1) The thermal conductivity is 4 W / m · K or higher, 2) The melting point peak in the scanning differential thermal analysis is in the range of 150 ° C to 300 ° C, and 3) The resin component conversion in the scanning differential thermal analysis Endotherm must be 5 J / g or more.

BEST MODE FOR CARRYING OUT THE INVENTION

The 4,4′-benzophenone-based epoxy resin (also referred to as a benzophenone-based epoxy resin) represented by the general formula (1) can be produced by reacting 4,4′-dihydroxybenzophenone and epichlorohydrin. . This reaction can be performed in the same manner as a normal epoxidation reaction. For example, after 4,4′-dihydroxybenzophenone is dissolved in an excess of epichlorohydrin, in the presence of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide, 50 to 150 ° C., preferably 60 to 100 ° C. A method of reacting in the range of 1 to 10 hours can be mentioned. In this case, the amount of the alkali metal hydroxide used is 0.8 to 1.2 mol, preferably 0.9 to 1.0 mol, relative to 1 mol of the 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 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 benzophenone is distilled off. -Based 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 in the epoxy resin synthesis reaction. can do. The value of n can be appropriately selected according to the application to be applied. For example, in semiconductor sealing applications where a high filler filling rate is required, those having low viscosity and crystallinity are preferred, and those having an average value of n in the range of 0.01 to 1.0 are preferred. Selected. When larger than this, a viscosity will become high and a handleability will fall.

The benzophenone-based epoxy resin used in the present invention can be synthesized using a mixture of 4,4'-dihydroxybenzophenone and another phenolic compound as a raw material. In this case, the mixing ratio of 4,4′-dihydroxybenzophenone is 50 wt% or more. Although there is no restriction | limiting in particular in a phenolic compound, The bifunctional thing which has two hydroxyl groups in 1 molecule is preferable.

The epoxy resin used in the present invention contains 50 wt% or more, preferably 80 wt% or more, more preferably 90 wt% or more of the benzophenone-based epoxy resin represented by the general formula (1) in the epoxy resin component. 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 appropriately selected according to the application. For example, in semiconductor sealing applications, low viscosity is preferable from the viewpoint of increasing the filling rate of inorganic filler and improving fluidity, and the epoxy equivalent mainly composed of n = 0 isomer in the above general formula (1) Is preferably in the range of 160 to 250. In applications such as laminates, it is preferably in the range of 400 to 20,000 from the viewpoint of imparting film properties and flexibility.

The form of the benzophenone-based epoxy resin represented by the general formula (1) is also appropriately selected according to the application. For example, in semiconductor sealing applications, since it is often handled as powder, a crystalline material that is solid at room temperature is preferable, a desirable melting point is 80 ° C. or higher, and a preferred melt viscosity at 150 ° C. is 0.005. To 0.2 Pa · s. Further, in applications such as laminates, there are many cases where they are used after being dissolved in a solvent, so that there are no particular restrictions on the form of the epoxy resin.

The purity of the epoxy resin used in 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.

In addition to the benzophenone-based 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 includes other epoxy resins having two or more epoxy groups in the molecule. You may use together. Examples include bisphenol A, 4,4′-dihydroxydiphenylmethane, 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxydiphenylmethane, 4,4′-dihydroxydiphenylsulfone, 4,4 ′. -Dihydroxydiphenyl sulfide, fluorene bisphenol, 4,4'-biphenol, 3,3 ', 5,5'-tetramethyl-4,4'-dihydroxybiphenyl, 2,2'-biphenol, resorcin, catechol, t-butyl Catechol, t-butylhydroquinone, 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, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2,8-dihydroxynaphthalene, allylated product or polyallylated product of the above-mentioned dihydroxynaphthalene Divalent phenols such as 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, fluoroglycinol 3 such as pyrogallol, t-butyl pyrogallol, allylated pyrogallol, polyallylated pyrogallol, 1,2,4-benzenetriol, 2,3,4-trihydroxybenzophenone, phenol aralkyl resin, naphthol aralkyl resin, dicyclopentadiene resin, etc. There are glycidyl etherified compounds derived from halogenated bisphenols such as tetrabromobisphenol A or higher phenols. These other epoxy resins can be used alone or in combination of two or more.

The epoxy resin composition of the present invention contains another type of epoxy resin as long as the blending ratio in the epoxy resin composition of the benzophenone-based epoxy resin represented by the general formula (1) is 50 wt% or more in the epoxy resin component. However, the total amount of the bifunctional epoxy resin is preferably 80 wt% or more, more preferably 90 wt% or more, from the viewpoint of improving the thermal conductivity when a cured product is obtained.

As the epoxy resin other than the benzophenone-based epoxy resin, a particularly preferable epoxy resin is a bisphenol-based epoxy resin represented by the following general formula (3).

(Wherein 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, X is a single bond, methylene group Represents an oxygen atom, a sulfone group, or a sulfur atom.)

The above bisphenol-based epoxy resins are 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 can be synthesized by carrying out a normal epoxidation reaction. These epoxy resins can be synthesized using those mixed with 4,4'-dihydroxybenzophenone at the raw material stage. Particularly preferred among these are epoxy resins synthesized from 4,4′-dihydroxybiphenyl, 4,4′-dihydroxydiphenylmethane, and 4,4′-dihydroxydiphenyl ether, which are crystalline epoxy resins having excellent handling properties. While giving resin, the molding excellent also in heat conductivity can be given.

The epoxy resin composition of the present invention uses, as an essential component, a benzophenone-based phenolic resin represented by the above general formula (2) as a curing agent. Here, the benzophenone-based phenolic resin is preferably 4,4'-dihydroxybenzophenone with m = 0.

In addition, when the epoxy resin composition of the present invention is applied as a prepreg for a laminated material, in the general formula (2), a benzophenone-based phenolic resin having an average value greater than 0 is preferably used. . In this case, a preferable value of m is 1 to 15 as an average value, and more preferably 2 to 15. The production method of the benzophenone-based phenolic resin having an increased m number is not limited. For example, an excessive amount of 4,4′-dihydroxy with respect to the benzophenone-based epoxy resin of the general formula (1) is used. A method of reacting benzophenone can be mentioned. Alternatively, it can be synthesized by reacting 1 mol or less of epichlorohydrin with 1 mol of hydroxyl group in 4,4'-dihydroxybenzophenone and 4,4'-dihydroxybenzophenone.

The hydroxyl group equivalent of the benzophenone-based phenolic resin represented by the general formula (2) is usually in the range of 100 to 20,000, but as with the epoxy resin, a suitable hydroxyl group equivalent is appropriately selected depending on the application. Is done. For example, in semiconductor sealing applications, low viscosity is preferable from the viewpoint of increasing the filling rate of inorganic filler and improving fluidity. In the above general formula (2), the hydroxyl equivalent equivalent having m = 0 as the main component Is preferably in the range of 100 to 200. In applications such as laminates, it is preferably in the range of 200 to 20,000 from the viewpoint of imparting film properties and flexibility. This hydroxyl equivalent is preferably satisfied even when two or more types of epoxy resins are used. In this case, the hydroxyl equivalent is calculated by the total weight (g) / hydroxyl group (mol).

The curing agent used in the epoxy resin composition of the present invention is generally known as an epoxy resin curing agent in addition to the benzophenone-based phenolic resin represented by the general formula (2) which is an essential component of the present invention. Although what can be combined as needed, Preferably the other phenol type hardening | curing agent which has a phenolic hydroxyl group is selected. Specific examples of other phenolic curing agents include bisphenol A, bisphenol F, 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-cresol 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-benzene Triol, 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, 2,6-dihydroxynaphthalene, 2,7-dihydride Examples thereof include roxynaphthalene, 2,8-dihydroxynaphthalene, allylated or polyallylated products of the above-mentioned dihydroxynaphthalene, allylated bisphenol A, allylated bisphenol F, allylated phenol novolak, allylated pyrogallol and the like.

The epoxy resin composition of the present invention contains another type of phenolic compound (resin) if the blending ratio of the benzophenone-based phenolic resin represented by the general formula (2) is 50 wt% or more in the curing agent component. However, the total amount of the bifunctional phenolic compound (resin) is preferably 80 wt% or more, more preferably 90 wt% or more, from the viewpoint of improving the thermal conductivity when the cured product is obtained. .

Particularly preferred as other phenolic compounds (resins) other than benzophenone-based phenolic resins are specifically hydroquinone, 4,4′-dihydroxybiphenyl, 4,4′-dihydroxydiphenylmethane, and 4,4′-dihydroxydiphenyl ether. 1,4-bis (4-hydroxyphenoxy) benzene, 4,4′-dihydroxydiphenyl sulfide, 1,5-naphthalenediol, 2,7-naphthalenediol, and 2,6-naphthalenediol. The amount of these bifunctional phenolic compounds or phenolic resins used is 50 wt% or less in the curing agent component, but preferably 20 wt% or less.

As the curing agent used in the epoxy resin composition of the present invention, in addition to the above-mentioned phenolic curing agent, other curing agents generally known as curing agents 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 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, diaminodiethyldi Chill diphenylmethane, alpha,. Alpha .'- 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 acid anhydride, nadic anhydride, methyl nadic anhydride, 5- (2,5 -The Xotetrahydro-3-furanyl) -3-methyl-3-cyclohexane-1,2-dicarboxylic anhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride 1-methyl-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride and the like.

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 terms of an equivalent ratio of the epoxy group and the functional group in the curing agent. Outside this range, an unreacted epoxy group or a functional group in the curing agent remains even after curing, which is not preferable because reliability as an electrical insulating material is lowered.

An inorganic filler may be added to the epoxy resin composition of the present invention. The addition amount of the inorganic filler is 50 to 95 wt% with respect to the epoxy resin composition, preferably 80 to 95 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 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 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. 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 among inorganic fillers, and alumina, aluminum nitride, crystalline silica, etc. are preferable. Used for. 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 diameter 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.

The inorganic filler may be a fibrous base material such as glass fiber, or a combination of a fibrous base material and a particulate inorganic filler. In the case of compounding with a fibrous base material, it is possible to obtain a prepreg of the present invention by using a solvent as a varnish and impregnating the sheet-like fibrous base material and drying it. The prepreg thus prepared is made of a metal substrate such as copper foil, aluminum foil or stainless steel foil, or a polymer such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, liquid crystal polymer, polyamide, polyimide, or Teflon (registered trademark). It can be applied as a printed wiring board, a heat radiating substrate, etc. by laminating with a base material and thermoforming.

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. The addition amount is usually in the range of 0.2 to 10 parts by weight with respect to 100 parts by weight of the epoxy resin. These may be used alone or in combination.

The addition amount of the curing catalyst is preferably 0.1 to 10.0% by mass with respect to the total of the epoxy resin (including the halogen-containing epoxy resin as a flame retardant) and the curing agent. If it is less than 0.1% by mass, the molding time becomes long, resulting in a decrease in workability due to a reduction in rigidity at the time of molding. Conversely, if it exceeds 10.0% by mass, curing proceeds during molding and unfilling occurs. It becomes easy.

In the epoxy resin composition of the present invention, a wax can be used as a release agent generally used for epoxy resin compositions. 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 the present invention, a coupling agent generally used for an epoxy resin composition can be used in order to improve the adhesion between the inorganic filler and the resin component. 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% by mass with respect to the epoxy resin composition. If it is less than 0.1% by mass, the compatibility between the resin and the base material is poor, and the moldability becomes poor.

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 / benzothiophenes. Examples thereof include copolymer resins. The addition amount is usually in the range of 2 to 30 parts by weight with respect to 100 parts by weight of the epoxy resin.

Further, the epoxy resin composition of the present invention can be used by appropriately blending those generally usable for epoxy resin compositions. 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 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. Further, after kneading, the melt-kneaded material can be pulverized to be powdered or tableted. The epoxy resin composition of this invention has an epoxy resin and a hardening | curing agent as a main component of a resin component. Preferably 60 wt% or more, more preferably 80 wt% or more is the epoxy resin and the curing agent.

The epoxy resin composition of the present invention is useful as an electrical insulating material, and is particularly suitably used for sealing in semiconductor devices.

In order to obtain a molded 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. During this molding, heating is performed and curing (polymerization) occurs. Therefore, since the obtained molded product is a molded product of polymerized resin (thermoplastic or thermosetting resin), it is also called a cured molded product. The term “curing” used in the present specification is used in the sense of including polymerization, and the cured resin is used in the sense of including a thermoplastic resin.

The molded product of the present invention is generally one that is three-dimensionally cross-linked, but is not necessarily a three-dimensional cross-linked product, and may be a molded product made of a thermoplastic two-dimensional polymer. . In particular, when a bifunctional epoxy resin is reacted with a bifunctional curing agent, a secondary hydroxyl group formed by a ring-opening reaction of an epoxy group usually reacts with the epoxy group to form a three-dimensional crosslinked product. By selecting curing conditions, a thermoplastic two-dimensional polymer molded body can be obtained. From the viewpoint of high thermal conductivity, it is desirable to form a crystalline molded product. However, since the three-dimensional crosslinking point generally inhibits the crystallinity, the number of crosslinking is reduced and a molded product mainly composed of a two-dimensional polymer is used. That is good. The expression of the crystallinity of the molded product can be confirmed by observing the endothermic peak accompanying melting of the crystal as a melting point by scanning differential thermal analysis. Usually, the melting point range is 120 ° C to 320 ° C, preferably 150 ° C to 300 ° C, more preferably 200 ° C to 280 ° C.

The higher the degree of crystallinity of the molded 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. Usually, the endothermic amount is 5 J / g or more per unit weight of the resin component excluding the filler, and the preferred endothermic amount is 10 J / g or more. More preferably, it is 20 J / g or more, and particularly preferably 30 J / g or more. When smaller than this, the heat conductivity improvement effect as an epoxy resin molding is small. Also, higher crystallinity is preferable from the viewpoint of low thermal expansion and improved heat resistance. 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 molded product of the present invention can be obtained by heat molding using the above molding method. Usually, the molding temperature is 80 ° C. to 250 ° C. However, in order to increase the crystallinity of the molded product, molding is performed. It is desirable to mold at a temperature lower than the melting point of the product. A preferred molding temperature is in the range of 100 ° C to 220 ° C, more preferably 150 ° C to 200 ° 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, but preferably 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 over 24 hours from the beginning. Moreover, the preferable heat conductivity of a molded object is 4 W / m * K or more, Most preferably, it is 6 W / m * K or more.

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

Reference example 1
1070 g of 4,4′-dihydroxydibenzophenone was dissolved in 6500 g of epichlorohydrin, and 808 g of 48% sodium hydroxide aqueous solution was added dropwise over 4 hours at 60 ° C. under reduced pressure (about 130 Torr). 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 continued for another hour, followed by dehydration. Then, epichlorohydrin was distilled off, 3500 g of methyl isobutyl ketone was added, and then washed with water to remove the salt. 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 light yellow crystalline epoxy resin (epoxy resin A).

Epoxy resin A had a melting point of 128 ° C. to 131 ° C. according to the capillary method, and a viscosity at 150 ° C. of 11.6 mPa · s. Epoxy equivalent is 179, hydrolyzable chlorine is 270 ppm, and each component ratio in the general formula (1) obtained by GPC measurement of the obtained resin is 91.0% for n = 0 and 8 for n = 1. .2%. Here, hydrolyzable chlorine is obtained by dissolving 0.5 g of a sample in 30 ml of dioxane, adding 1N-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 conducting potentiometric titration with 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. Viscosity was measured with CAP2000H manufactured by BROOKFIELD, and softening point was measured by ring and ball method according to JIS K-6911. In addition, GPC measurement was performed by using an apparatus: Nippon Waters Co., Ltd. Model 515A, column: TSK-GEL2000 × 3 and TSK-GEL4000 × 1 (both manufactured by Tosoh Corporation), solvent: tetrahydrofuran, flow rate: 1 ml / min, temperature; 38 ° C., detector; RI conditions were followed.

Examples 1-6, Comparative Examples 1-5
As an epoxy resin component, the epoxy resin (epoxy resin A) of Reference Example 1, an epoxidized product of 4,4′-dihydroxydiphenyl ether (epoxy resin B: manufactured by Tohto Kasei Co., Ltd., YSLV-80DE, epoxy equivalent 174) or biphenyl epoxy resin ( Epoxy resin C: YE-4000H manufactured by Japan Epoxy Resin, epoxy equivalent 195), 4,4′-dihydroxydibenzophenone (curing agent A), 4,4′-dihydroxydiphenyl ether (curing agent B) as a curing agent 4,4′-dihydroxydiphenylmethane (curing agent C), 4,4′-dihydroxydibenzophenone (curing agent D) or phenol novolak (curing agent E: manufactured by Gunei Chemical Co., Ltd., PSM-4261; OH equivalent 103, softening point 82 ° C.) was 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, mixed thoroughly with a mixer, then kneaded for about 5 minutes with a heating roll, cooled and ground to obtain the epoxy resin compositions of Examples 1 to 6 and Comparative Examples 1 to 5, respectively. Obtained. Using this epoxy resin composition, molding and post-curing were performed under the conditions shown in Table 1, and the physical properties of the molded product were evaluated.

The results are summarized in Tables 1 and 2. In addition, the number of each compound in a table | surface represents a weight part. The evaluation was performed as follows.

(1) Thermal conductivity: 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 (DSC6200, manufactured by Seiko Instruments Inc.), the temperature was increased at a rate of 10 ° C./min.
(3) Linear expansion coefficient, glass transition temperature: Measured at a heating rate of 10 ° C./min using a TMA120C type thermomechanical measuring device manufactured by Seiko Instruments Inc.
(4) Water absorption: A disk having a diameter of 50 mm and a thickness of 3 mm was formed, and after post-curing, the weight change rate was obtained after moisture absorption at 85 ° C. and a relative humidity of 85% for 100 hours.

Industrial applicability

The epoxy resin composition of the present invention provides a cured molded product that is excellent in moldability and reliability, and has high thermal conductivity, low water absorption, low thermal expansion, and high heat resistance. It is suitably applied as an insulating material for electric and electronic parts such as substrates, and exhibits excellent high heat dissipation and dimensional stability.

Claims

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

(However, n represents a number from 0 to 15.)
And 4 wt ′ or more of the curing agent represented by the following general formula (2):

(However, m represents a number from 0 to 15.)
An epoxy resin characterized in that the equivalent ratio of the epoxy group in the epoxy resin and the functional group in the curing agent is in the range of 0.8 to 1.5. Resin composition.
The epoxy resin composition according to claim 1, comprising 50 to 95 wt% of an inorganic filler.
The epoxy resin composition according to claim 1, which is an epoxy resin composition for semiconductor encapsulation.
A prepreg comprising a sheet-like fiber base material impregnated with the epoxy resin composition according to claim 1 or 2 into a semi-cured state.
A molded product obtained by heat-molding the epoxy resin composition according to any one of claims 1 to 3.
The molded article according to claim 5, wherein the thermal conductivity is 4 W / m · K or more.
The molded product according to claim 5, wherein the peak of the melting point in the scanning differential thermal analysis is in the range of 150 ° C to 300 ° C.
The molded article according to claim 5, wherein the endothermic amount in terms of resin component in the scanning differential thermal analysis is 5 J / g or more.