WO2023149493A1 - Epoxy resin, epoxy resin composition, and epoxy resin cured product - Google Patents

Abstract

The present invention provides an epoxy resin that has favorable melt-kneadability, has solvent solubility, and is for use in layering, molding, casting, adhesion, or the like. The present invention also provides an epoxy resin composition and a cured product of the epoxy resin composition. According to the present invention, an epoxy resin is characterized by being an epoxy resin represented by general formula (1). (In the formula: X independently represents a direct bond, an oxygen atom, a sulfur atom, -SO2-, -CO-, -COO-, -CONH-, -CH2-, or -C(CH3)2-; A independently represents benzonitrile or -(CH2)m-, provided that at least one molecule has both structures; n is a number from 2 to 15; and m is a number from 3 to 10).

Description

EPOXY RESIN, EPOXY RESIN COMPOSITION AND EPOXY RESIN CURED MATERIAL

TECHNICAL FIELD The present invention relates to epoxy resins, epoxy resin compositions, and cured epoxy resins. More specifically, the present invention relates to an epoxy resin, an epoxy resin composition, and a cured epoxy resin, which are useful as insulating materials for electric and electronic parts such as semiconductor encapsulation, laminates, and heat dissipation substrates, and have good handleability as solids at room temperature. , epoxy resins and epoxy resin compositions having low viscosity during molding and excellent solvent solubility, and epoxy resin cured products having excellent heat resistance, thermal decomposition stability, and thermal conductivity obtained by curing them.

Epoxy resins have been used in a wide range of industrial applications, but the required performance has become more sophisticated in recent years. In the electric/electronics field and the power electronics field, where electronic circuits are becoming more dense and higher in frequency, the amount of heat generated from electronic circuits is increasing. It's becoming Conventionally, this heat dissipation has been covered by the thermal conductivity of the filler, but in order to achieve higher integration, it has become necessary to improve the thermal conductivity of the matrix epoxy resin itself.

As an epoxy resin composition excellent in high thermal conductivity, one using an epoxy resin having a mesogenic structure is known. It discloses an epoxy resin composition as a component, which is excellent in stability and strength at high temperatures and can be used in a wide range of fields such as adhesion, casting, sealing, molding and lamination. Further, Patent Document 2 discloses an epoxy compound having two mesogenic structures linked by a bent chain in its molecule. Furthermore, Patent Document 3 discloses a resin composition containing an epoxy compound having a mesogenic group.

However, epoxy resins with such a mesogenic structure have a high melting point, and when mixed, the high-melting-point component is difficult to dissolve and remains undissolved, resulting in reduced curability and heat resistance. Also, a high temperature was required to uniformly mix such an epoxy resin with a curing agent. At high temperatures, the curing reaction of the epoxy resin proceeds rapidly and the gelling time is shortened. If a third component with good solubility is added to make up for this drawback, the melting point of the resin is lowered to facilitate uniform mixing, but the resulting cured product has a problem of reduced thermal conductivity.

As a high thermal conductivity resin that can be melt-mixed, Patent Document 4 discloses an epoxy resin obtained by epoxidizing a mixture of hydroquinone and 4,4'-dihydroxybiphenyl, and Patent Document 5 discloses 4,4'-dihydroxy Epoxy resins are disclosed which are epoxidized mixtures of diphenylmethane and 4,4'-dihydroxybiphenyl. However, these resins are poorly soluble in solvents and have limited applications. Patent Document 6 discloses an epoxy resin composition having a diphenyl ether structure, but the curing agent is limited, and general-purpose curing agents such as phenol novolak are insufficient in thermal conductivity and heat resistance. .

JP-A-7-90052 JP-A-9-118673 JP-A-11-323162 WO2009/110424 JP 2010-43245 A JP 2012-17405 A

Accordingly, an object of the present invention is to solve the above problems, and to provide excellent handleability as a solid at normal temperature, which is useful as an insulating material for electric and electronic parts such as highly reliable semiconductor encapsulation, laminates, and heat dissipation substrates. An object of the present invention is to provide an epoxy resin having low viscosity during molding and excellent solvent solubility, an epoxy resin composition using the same, and a cured product obtained therefrom having excellent high thermal conductivity.

Through intensive studies, the present inventors have found that a specific epoxy resin having a benzonitrile structure and an alkyl structure in the molecular chain is expected to solve the above problems, and that the cured product has thermal conductivity and heat resistance. It was found that the effect was expressed in sex.

That is, the present invention is an epoxy resin characterized by being represented by the following general formula (1).

(wherein X is independently a direct bond, an oxygen atom, a sulfur atom, -SO ₂ -, -CO-, -COO-, -CONH-, -CH ₂ - or -C(CH ₃ ) ₂ - A independently represents a benzonitrile structure or -(CH ₂ )m-, having both structures in at least one molecule, n represents a number from 2 to 15, and m represents a number from 3 to 10.)
The present invention also relates to an epoxy resin represented by general formula (2).

(However, p and q each independently represent a number from 1 to 15, and m represents a number from 3 to 10.)

Further, the present invention relates to an epoxy resin composition characterized by comprising the above epoxy resin and a curing agent as essential components, and an epoxy resin cured product characterized by curing the epoxy resin cured product. is.

The epoxy resin of the present invention has good melt-kneadability at 100 ° C. or less, has solvent solubility, and is used for lamination, molding, casting, adhesion, etc. Epoxy resin composition and cured product thereof Suitable for This cured product is also excellent in heat resistance, thermal decomposition stability, and thermal conductivity.

1 is an FD-MS spectrum of the phenolic compound (hydroxy resin) obtained in Example 1. FIG. 1 is a GPC chart of a phenolic compound (hydroxy resin) obtained in Example 1. FIG. 1 is a GPC chart of the epoxy resin obtained in Example 1. FIG.

The present invention will be described in detail below.

First, the present invention is an epoxy resin represented by general formula (1).

X independently represents a direct bond, an oxygen atom, a sulfur atom, --SO ₂ --, --CO--, --COO--, --CONH--, --CH ₂ -- or --C(CH ₃ ) ₂ --. A independently represents a benzonitrile structure or —(CH ₂ ) _m —, and has both the benzonitrile structure and —(CH ₂ ) _m — in at least one molecule. n represents a number from 2 to 15 and m represents a number from 3 to 10. From the viewpoint of high thermal conductivity, X is preferably a biphenyl structure that is a direct bond, —SO ₂ —, —CO—, —COO— or —CONH—, more preferably a biphenyl structure that is a direct bond, of which 4, A biphenyl structure at the 4'-position is particularly preferred. On the other hand, an oxygen atom, a sulfur atom, —CH ₂ —, and —C(CH ₃ ) ₂ — are preferred from the standpoint of moldability and solvent solubility. At that time, as described above as "independently", the epoxy resin of the formula (1) of the present invention can be a mixture of structures in which X is different, and has high thermal conductivity, moldability, and solvent solubility. can be adjusted.

　n is the number of repetitions (number average) and indicates a number from 2 to 15. Preferred are mixtures of components with different values of n. The epoxy resin of the present invention may be a mixture with a compound of n = 0 or 1 represented by the general formula (1), and the area % (GPC area %) measured by gel permeation chromatography, n = 0 is preferably 40% or less. More preferably, it is 35% or less. When n=0 is contained more than 40%, the crystallinity is strong, the melting point is 135° C. or higher, and solvent solubility tends to decrease. In addition, when n is larger than 15, the reactivity tends to be low, and the heat resistance tends to decrease when unreacted components are generated during curing. A preferred range for n is 2-12, more preferably 2-8.

A represents a benzonitrile structure or an alkyl structure represented by -(CH ₂ ) _m -. As described above, at least one molecule has both the benzonitrile structure and the alkyl structure represented by —(CH ₂ ) _m —. That is, as A is also "independently", the epoxy resin of the formula (1) of the present invention can be a mixture of structures in which A is different, and has high thermal conductivity, moldability, and solvent solubility. It is possible to adjust gender. The ratio of the benzonitrile structure and the alkyl structure is preferably 50 mol% or less, more preferably 10 mol% to 40 mol%, more preferably 20 mol% to 40 mol%, based on the mass of the raw material compound. More preferred. When the alkyl structure is more than 50 mol %, the thermal conductivity and heat resistance of the cured product tend to decrease, and when the alkyl structure is not included, the crystallinity tends to increase and solvent solubility tends to decrease.

m is the number of repetitions and indicates a number from 3 to 10. More preferably, it is a number of 4-8. If it is less than 3, the flexibility tends to be low and the effect of alleviating crystallinity tends to be low. If it is greater than 10, the thermal conductivity and heat resistance of the cured product tend to be greatly reduced.

Specifically, an epoxy resin represented by the following formula (2) can be preferably exemplified.

(However, p and q each independently represent a number from 1 to 15, and m represents a number from 3 to 10.)

p and q are the number of repetitions (number average) and indicate numbers from 1 to 15. A preferred range for p is 1-10, more preferably 1-7. A preferred range for q is 1-7, more preferably 1-3. When p is larger than 15, solvent solubility tends to decrease, and when q is larger than 15, thermal conductivity and heat resistance of the cured product tend to decrease.

The softening point of the epoxy resin of the present invention (including a mixture with a compound represented by the general formula (1) where n = 0 or 1; the same shall apply hereinafter) is preferably 135°C or less. If the temperature is higher than 135°C, the melt-kneadability is lowered, and if it has crystallinity, the solvent solubility is also lowered.

The epoxy equivalent of the epoxy resin of the present invention is 200-280 g/eq. is preferred. If it exceeds this range, the reactivity tends to be low, and unreacted components are produced during curing, which tends to reduce heat resistance and reliability. If it is less than this range, it means that the bifunctional epoxy resin component that does not contain a benzonitrile structure or an alkyl structure increases. When the amount of the functional liquid epoxy resin is large, the heat resistance and thermal conductivity of the cured product tend to decrease.

Although the method for producing the epoxy resin of the present invention is not particularly limited, it is produced by reacting a phenolic compound represented by the following formula (3) (also referred to as a hydroxy resin; the same shall apply hereinafter) with epichlorohydrin. can do. This reaction can be carried out in the same manner as a normal epoxidation reaction. Further, when the raw material is a mixture with a compound represented by formula (3) where n = 0 or 1, the epoxy resin obtained by this production method is not only the epoxy resin of the present invention, but also the epoxy resin of the present invention, as described above. and the epoxidized compound of the compound represented by the general formula (1) where n=0 or 1.

(wherein X is independently a direct bond, an oxygen atom, a sulfur atom, -SO ₂ -, -CO-, -COO-, -CONH-, -CH ₂ - or -C(CH ₃ ) ₂ - Each A independently represents a benzonitrile structure or -(CH ₂ ) _m -, at least one of which represents -(CH ₂ ) _m -, and has both structures in at least one molecule. m is each independently, n is 2 to 15, m is 3 to 10.)
The phenolic compound represented by formula (3) (including a mixture with a compound where n = 0 or 1) has a hydroxyl equivalent (g/eq.) of preferably 150 to 230, more preferably 170. ~220. Also, the melting point is preferably 140°C to 300°C, more preferably 150°C to 250°C.

Here, the phenolic compound represented by formula (3) is not limited, but examples include 2,4-dichlorobenzonitrile, 2,5-dichlorobenzonitrile, 2,6-dichlorobenzonitrile, 3,5 - benzonitrile compounds such as dichlorobenzonitrile, 2,4-dibromobenzonitrile, 2,5-dibromobenzonitrile, 2,6-dibromobenzonitrile, 3,5-dibromobenzonitrile, and 1,3-dibromopropane, Dihalogen alkyl compounds such as 1,4-dibromobutane, 1,5-dibromopentane, 1,6-dibromohexane, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4' -Dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxybenzophenone, bisphenol A, bisphenol F, etc. obtained by a method of reacting a dihydroxy compound having the above X group in the presence of a basic catalyst be able to. The method for producing the phenolic compound is not particularly limited, but for example, the method described in WO2021/201046 can be used. Regarding the charge ratio (molar ratio) for the reaction at this time, for the purpose of achieving both the solvent solubility of the resulting resin and the thermal conductivity of the cured product, the total amount of the benzonitrile compound and the dihalogenalkyl compound is set to X It is preferable to charge the dihydroxy compound having a group at 1 to 4 times the molar amount. More preferably, it is charged in a 2- to 3-fold molar amount. The usage ratio of the benzonitrile compound and the dihalogenalkyl compound is as described above.

The reaction of the phenolic compound of formula (3) (including a mixture with a compound of n = 0 or 1) and epichlorohydrin can be carried out, for example, by dissolving the phenolic compound in excess epichlorohydrin, then adding sodium hydroxide, water A method of reacting at 50 to 150° C., preferably 60 to 100° C. for 1 to 10 hours in the presence of an alkali metal hydroxide such as potassium oxide can be mentioned. At this time, the amount of alkali metal hydroxide to be used is in the range of 0.8 to 2.0 mol, preferably 0.9 to 1.5 mol, per 1 mol of hydroxyl group in the dihydroxy compound. Epichlorohydrin is used in an excess amount relative to the hydroxyl groups in the phenolic compound, usually 1.5 to 15 mol per 1 mol of hydroxyl groups in the phenolic compound. After completion of the reaction, 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 the solvent is distilled off to obtain the desired epoxy. resin can be obtained.

The epoxy resin of the present invention can also be synthesized using a mixture of the phenolic compound represented by general formula (3) and other phenolic compounds. In this case, the mixing ratio of the phenolic compound represented by general formula (3) is preferably 50 wt % or more. Also, other phenolic compounds are not particularly limited, and are selected from those having two or more hydroxyl groups in one molecule.

The purity of this epoxy resin, particularly the amount of hydrolyzable chlorine, should be less 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. In addition, the hydrolyzable chlorine referred to in the present invention refers to the value measured by the following method. That is, after dissolving 0.5 g of the sample in 30 ml of dioxane, 10 ml of 1N-KOH was added and the mixture was boiled and refluxed for 30 minutes, cooled to room temperature, further 100 ml of 80% acetone water was added, and a potential difference was obtained with an aqueous 0.002N- _AgNO3 solution. It is a value obtained by titration.

In the epoxy resin composition of the present invention, in addition to the epoxy resin of formula (1) used as an essential component, other epoxy resins having two or more epoxy groups in the molecule may be used in combination as epoxy resin components. . Examples include bisphenol A, bisphenol F, 3,3′,5,5′-tetramethyl-4,4′-dihydroxydiphenylmethane, 4,4′-dihydroxydiphenyl sulfone, 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-butyl catechol, t-butyl hydroquinone, 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-dihydroxy Naphthalene, allylated or polyallylated dihydroxynaphthalene, allylated bisphenol A, allylated bisphenol F, dihydric phenols such as 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 , t-butyl pyrogallol, allylated pyrogallol, polyallylated pyrogallol, 1,2,4-benzenetriol, 2,3,4-trihydroxybenzophenone, phenol aralkyl resin, naphthol aralkyl resin, dicyclopentadiene-based resin, etc. There are glycidyl etherified products derived from the above phenols or halogenated bisphenols such as tetrabromobisphenol A. These epoxy resins can be used singly or in combination of two or more.

The blending ratio of the epoxy resin of formula (1) used in the epoxy resin composition of the present invention is 50 wt% or more, preferably 70 wt% or more, more preferably 90 wt% or more of the total epoxy resin. Furthermore, it is desirable that the total amount of the bifunctional epoxy resin is 90 wt % or more, preferably 95 wt % or more. If the amount is less than this, there is a possibility that the effect of improving physical properties such as thermal conductivity in the cured product may be reduced. This is because the higher the content of the epoxy resin of formula (1) and the higher the content of the bifunctional epoxy resin, the higher the degree of orientation of the molded product.

As the curing agent used in the epoxy resin composition of the present invention, all those generally known as curing agents for epoxy resins can be used, including dicyandiamide, acid anhydrides, polyhydric phenols, aromatic and aliphatic amines. etc. Among these, polyhydric phenols are preferably used as a curing agent in fields such as semiconductor encapsulants that require high electrical insulation. Specific examples of the curing agent are shown below.

Examples of polyhydric phenols include dihydric phenols such as bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4'-biphenol, 2,2'-biphenol, hydroquinone, resorcinol, naphthalene diol, or , tris-(4-hydroxyphenyl)methane, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, phenol novolak, o-cresol novolak, naphthol novolak, polyvinylphenol, etc. There are phenols. Furthermore, dihydric phenols such as phenols, naphthols, bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4'-biphenol, 2,2'-biphenol, hydroquinone, resorcinol, and naphthalenediol, There are polyhydric phenolic compounds synthesized with condensing agents such as formaldehyde, acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde and p-xylylene glycol.

Examples of acid anhydride curing agents include phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyl himic anhydride, dodecynylsuccinic anhydride, nadic anhydride, and trimellitic anhydride.

Amine curing agents include aromatic amines such as 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylsulfone, m-phenylenediamine and p-xylylenediamine; There are aliphatic amines such as ethylenediamine, hexamethylenediamine, diethylenetriamine and triethylenetetramine.

One or a mixture of two or more of these curing agents can be used in the epoxy resin composition.

The blending ratio of the epoxy resin and the curing agent is preferably in the range of 0.8 to 1.5 in terms of the equivalent ratio of the epoxy groups to the functional groups in the curing agent. Outside this range, unreacted epoxy groups or functional groups in the curing agent remain even after curing, which may reduce the reliability of the sealing function.

In the epoxy resin composition of the present invention, oligomers or polymer compounds such as polyester, polyamide, polyimide, polyether, polyurethane, petroleum resin, indene resin, indene-cumarone resin, phenoxy resin, etc. may be used as other modifiers. It may be blended as appropriate. The amount added is usually in the range of 1 to 30 parts by weight with respect to 100 parts by weight of the total resin components.

Additives such as inorganic fillers, pigments, flame retardants, thixotropic agents, coupling agents, fluidity improvers and the like can be added to the epoxy resin composition of the present invention. Examples of inorganic fillers include spherical or crushed fused silica, silica powder such as crystalline silica, alumina powder, glass powder, mica, talc, calcium carbonate, alumina, and hydrated alumina. When used as a sealing material, the blending amount is preferably 70% by weight or more, more preferably 80% by weight or more.

Pigments include organic or inorganic extender pigments and scaly pigments. Examples of the thixotropic agent include silicon-based, castor oil-based, aliphatic amide wax, oxidized polyethylene wax, and organic bentonite-based agents.

A curing accelerator can be used in the epoxy resin composition of the present invention as necessary. Examples include amines, imidazoles, organic phosphines, Lewis acids, etc. Specific examples include 1,8-diazabicyclo(5,4,0)undecene-7, triethylenediamine, benzyldimethylamine, tri Tertiary amines such as ethanolamine, dimethylaminoethanol, tris(dimethylaminomethyl)phenol, 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, 2- imidazoles such as heptadecyl imidazole; organic phosphines such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine, and phenylphosphine; tetraphenylphosphonium/tetraphenylborate; tetraphenylphosphonium/ethyltriphenylborate; Tetra-substituted phosphonium/tetra-substituted borate such as butylphosphonium/tetrabutylborate, tetraphenylboron salts such as 2-ethyl-4-methylimidazole/tetraphenylborate, and N-methylmorpholine/tetraphenylborate. The amount added is usually in the range of 0.01 to 5 parts by weight per 100 parts by weight of the total resin components.

Furthermore, if necessary, the epoxy resin composition of the present invention may contain a releasing agent such as carnauba wax or OP wax, a coupling agent such as γ-glycidoxypropyltrimethoxysilane, a coloring agent such as carbon black, Flame retardants such as antimony oxide, stress reducing agents such as silicone oil, and lubricants such as calcium stearate can be used.

The epoxy resin composition of the present invention is made into a varnish state by dissolving an organic solvent, impregnated with a fibrous material such as a glass cloth, an aramid nonwoven fabric, a polyester nonwoven fabric such as a liquid crystal polymer, etc., and then the solvent is removed to form a prepreg. can do. In some cases, a laminate can be obtained by coating a sheet-like material such as a copper foil, a stainless steel foil, a polyimide film, a polyester film, or the like.

By curing the epoxy resin composition of the present invention by heating, the resin cured product of the present invention can be obtained. This cured product can be obtained by molding the epoxy resin composition by a method such as casting, compression molding, or transfer molding. The temperature at this time is usually in the range of 120 to 220°C.

The present invention will be specifically described below with reference to examples and comparative examples. However, the present invention is not limited to these. Unless otherwise specified, "parts" represent parts by weight and "%" represents weight percent. Moreover, the measurement method was each measured by the following methods.  

1) Epoxy equivalent Using a potentiometric titrator, using methyl ethyl ketone as a solvent, adding a tetraethylammonium bromide acetic acid solution, and measuring using a 0.1 mol/L perchloric acid-acetic acid solution with a potentiometric titrator.

2) OH equivalent Using a potentiometric titrator, 1,4-dioxane is used as a solvent, acetylation is performed with 1.5 mol/L acetyl chloride, and excess acetyl chloride is decomposed with water to 0.5 mol/L-water. It was titrated using potassium oxide.

3) Melting point A DSC peak temperature was obtained with a differential scanning calorimeter (EXSTAR6000 DSC/6200, manufactured by SII Nanotechnology Co., Ltd.) under the condition of a heating rate of 5°C/min. That is, this DSC peak temperature was taken as the melting point of the resin.

4) Melt viscosity Measured at 150°C using a CAP2000H rotational viscometer manufactured by BROOKFIELD.

5) Softening point Measured by the ring and ball method according to JIS-K-2207.

6) GPC Measurement A main body (HLC-8220GPC, manufactured by Tosoh Corporation) equipped with columns (4 TSKgel SuperMultiporeHZ-N, manufactured by Tosoh Corporation) in series was used, and the column temperature was set to 40°C. Tetrahydrofuran (THF) was used as an eluent at a flow rate of 0.35 mL/min, and a differential refractive index detector was used as a detector. As a measurement sample, 0.1 g of the sample was dissolved in 10 mL of THF and filtered through a microfilter, and 50 μL of the solution was used. For data processing, GPC-8020 model II version 6.00 manufactured by Tosoh Corporation was used.

7) Glass transition point (Tg)
Tg was determined at a temperature increase rate of 10° C./min using a thermomechanical measurement device (EXSTAR TMA/7100 manufactured by SII Nanotechnology Co., Ltd.).

8) 5% weight loss temperature (Td5), residual carbon ratio Using a thermogravimetric/differential thermal analyzer (EXSTAR TG/DTA7300, manufactured by SII Nanotechnology), under a nitrogen atmosphere, at a heating rate of 10 ° C./min. Under these conditions, the 5% weight loss temperature (Td5) was measured. Also, the weight loss at 700° C. was measured and calculated as the residual charcoal rate.

9) Thermal conductivity Thermal conductivity was measured by the unsteady hot wire method using a NETZSCH LFA447 thermal conductivity meter.

10) Melt-kneadability Melt-kneadability at 100°C was confirmed. ○ indicates that kneading is possible, Δ indicates that kneading is difficult, and x indicates that unmelted components are present.

11) Solvent Solubility After weighing 2 g of the resin composition and 2 g of methyl ethyl ketone into a sample bottle and heating and dissolving them, the temperature was gradually lowered in a constant temperature bath, and the temperature in the bath where the resin was deposited was measured.
A deposition temperature of 25° C. or less was evaluated as ◯, a deposition temperature of 26° C. or more and less than 60° C. was evaluated as Δ, and a deposition temperature of 60° C. or more was evaluated as X.

12) Field desorption ionization mass spectrometry (FD-MS)
It was measured using a mass spectrometer JMS-T100GCV (manufactured by JEOL Ltd.). A sample was dissolved in acetone and subjected to measurement.

Example 1
After dissolving 81.8 g of 4,4′-dihydroxybiphenyl, 6.7 g of 1,5-dibromopentane and 500 g of N-methyl-2-pyrrolidone in a 2 L four-necked separable flask, 32.4 g of potassium carbonate was added, The temperature was raised to 120° C. while stirring under a nitrogen stream. After that, 20.2 g of 2,6-dichlorobenzonitrile was added, the temperature was raised to 145° C., and reaction was carried out for 6 hours. After neutralizing the reaction mixture by adding 28.2 g of acetic acid, N-methyl-2-pyrrolidone was distilled off under reduced pressure. After adding 250 mL of methyl isobutyl ketone to the reaction solution to dissolve the product, the resulting salt was removed by washing with water. Thereafter, methyl isobutyl ketone was removed by vacuum distillation to obtain 79 g of hydroxy resin. The hydroxyl equivalent of the obtained hydroxy resin was 158 g/eq. , a melting point of 263° C. and an Mn of 430. The FD-MS spectrum of the obtained hydroxy resin is shown in FIG. 1, and the GPC chart is shown in FIG.
Next, 690 g of epichlorohydrin and 140 g of diethylene glycol dimethyl ether were added to 79 g of the obtained hydroxy resin, and 54.5 g of a 48% aqueous sodium hydroxide solution was added dropwise at 65° C. under reduced pressure (about 130 Torr) over 3 hours. During this time, the generated water was removed from the system by azeotroping with epichlorohydrin, and the distilled epichlorohydrin was returned to the system. After the dropwise addition was completed, the reaction was continued for 1 hour to remove water. Thereafter, epichlorohydrin was distilled off under reduced pressure, methyl isobutyl ketone was added, and after removing the salt by washing with water, filtration and washing were carried out, and methyl isobutyl ketone was distilled off under reduced pressure to obtain 81 g of an epoxy resin solid at room temperature (81 g). Epoxy resin A). The obtained epoxy resin A had a softening point of 130° C. and an epoxy equivalent of 230 g/eq. , the melt viscosity was 0.05 Pa·s, the n = 0 body measured by GPC was 38%, and the Mn was 330. A GPC chart of the obtained epoxy resin A is shown in FIG.

Example 2
The reaction was carried out in the same manner as in Example 1 except that the amount of 1,5-dibromopentane used was 13.5 g and the amount of 2,6-dichlorobenzonitrile used was 15.2 g to obtain 77 g of an epoxy resin. (epoxy resin B). The obtained epoxy resin B had a softening point of 133° C. and an epoxy equivalent of 224 g/eq. , the melt viscosity was 0.04 Pa·s, the n = 0 body measured by GPC was 38%, and the Mn was 310. Incidentally, the hydroxyl equivalent of the intermediate hydroxy resin was 159 g/eq. , a melting point of 257° C. and an Mn of 370.

Example 3
The reaction was carried out in the same manner as in Example 1 except that the amount of 1,5-dibromopentane used was changed to 20.2 g and the amount of 2,6-dichlorobenzonitrile used was changed to 22.7 g to obtain 82 g of an epoxy resin. . (epoxy resin C). The obtained epoxy resin C had a softening point of 120° C. and an epoxy equivalent of 263 g/eq. , the melt viscosity was 0.07 Pa·s, the n = 0 body measured by GPC was 29%, and the Mn was 390. Incidentally, the hydroxyl group equivalent of the intermediate hydroxy resin was 226 g/eq. , a melting point of 245° C. and an Mn of 520.

Example 4
The reaction was carried out in the same manner as in Example 1, except that 21.5 g of 1,6-dibromohexane and 22.7 g of 2,6-dichlorobenzonitrile were used instead of 1,5-dibromopentane. 79 g of epoxy resin were obtained. (epoxy resin D). The obtained epoxy resin D had a softening point of 109° C. and an epoxy equivalent of 253 g/eq. , the melt viscosity was 0.09 Pa·s, the n = 0 body measured by GPC was 29%, and the Mn was 330. Incidentally, the hydroxyl equivalent of the intermediate hydroxy resin was 222 g/eq. , a melting point of 240° C. and an Mn of 560.

Comparative example 1
The reaction was carried out in the same manner as in Example 1 except that 1,5-dibromopentane was not used and the amount of 2,6-dichlorobenzonitrile used was changed to 25.2 g to obtain 74 g of an epoxy resin. (epoxy resin E). The resulting epoxy resin E has crystallinity, a melting point of 139° C. and an epoxy equivalent of 226 g/eq. , the melt viscosity was 0.10 Pa·s, the n = 0 body measured by GPC was 34%, and the Mn was 400. Incidentally, the hydroxyl group equivalent of the intermediate hydroxy resin was 220 g/eq. , a melting point of 272° C. and an Mn of 500.

Comparative example 2
The reaction was carried out in the same manner as in Example 1 except that 2,6-dichlorobenzonitrile was not used and the amount of 1,5-dibromopentane used was changed to 33.8 g to obtain 45 g of hydroxy resin. The resulting hydroxy resin had a melting point of 300° C. or higher and was insoluble in the solvent, so the epoxidation reaction did not proceed.

Examples 5-8 and Comparative Examples 3-5
As epoxy resin components, epoxy resin A obtained in Example 1, epoxy resin B obtained in Example 2, epoxy resin C obtained in Example 3, epoxy resin D obtained in Example 4, and epoxy resin D obtained in Comparative Example 1 were used. Epoxy resin E, epoxy resin F (4,4'-dihydroxydiphenyl ether type epoxy resin, epoxy equivalent 163 g / eq.; YSLV-80DE, manufactured by Nippon Steel Chemical & Material) and epoxy resin G (biphenyl type epoxy resin, epoxy equivalent 195 g / eq.; YX-4000H, manufactured by Mitsubishi Chemical), a phenol novolac resin (OH equivalent 105, softening point 83 ° C.; BRG-557, manufactured by Aica Kogyo) as a curing agent, and tritri as a curing accelerator. Using phenylphosphine, an epoxy resin composition having the composition shown in Table 1 was obtained. Table 1 shows the melt kneadability and solvent solubility of the epoxy resin composition. Numerical values in the table indicate parts by weight in the formulation.
This epoxy resin composition was molded at 175° C. and post-cured at 175° C. for 5 hours to obtain a cured product test piece. served to

As is clear from these results, the epoxy resins obtained in the examples have excellent melt-kneadability and solvent solubility, and the cured products thereof have good thermal stability and thermal conductivity. Suitable.

Epoxy resin cured products obtained from the epoxy resin composition of the present invention are suitable for encapsulation of electrical and electronic parts, circuit board materials, and the like.

Claims (5)

1. An epoxy resin characterized by being represented by the following general formula (1).
   

   

   (wherein X is independently a direct bond, an oxygen atom, a sulfur atom, -SO ₂ -, -CO-, -COO-, -CONH-, -CH ₂ - or -C(CH ₃ ) ₂ - A independently represents a benzonitrile structure or --(CH ₂ ) _m --, having both structures in at least one molecule, n represents a number of 2-15, and m represents a number of 3-10. )
2. The epoxy resin according to claim 1, wherein X is a direct bond.
3. 2. The epoxy resin according to claim 1, characterized by being represented by the following general formula (2).
   

   

   (However, p and q each independently represent a number from 1 to 15, and m represents a number from 3 to 10.)
4. An epoxy resin composition characterized by comprising the epoxy resin according to any one of claims 1 to 3 as an essential component.
5. A cured epoxy resin obtained by curing the epoxy resin composition according to claim 4 .
   

Images