JP2023033883A - Epoxy resin, its composition and cured product - Google Patents

Abstract

To provide a crystalline epoxy resin that is useful for semiconductor sealing and available as an insulation material for electric and electronic components such as a laminate or a heat radiation substrate, has excellent handleability as a solid at normal temperature, and also excels in low viscosity during molding and solvent solubility, an epoxy resin composition including the same, and a cured product obtained therefrom.SOLUTION: An epoxy resin is represented by general formula (1), and has an epoxy equivalent of 230-350 g/eq and a softening point of 130°C or lower. There are also provided a resin composition including the same and a cured product thereof.SELECTED DRAWING: Figure 1

Description

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, and their required performance has become increasingly sophisticated in recent years. In the electric/electronics field and the power electronics field, where electronic circuits are increasing in density and frequency, heat generation 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, such an epoxy resin having a mesogenic structure has a high melting point, and when a mixing treatment is performed, the high melting point component is difficult to dissolve and remains undissolved, resulting in a problem of 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. When a third component with good solubility is added to make up for the drawback, the melting point of the resin is lowered and uniform mixing becomes easier, but the cured product has a problem of reduced thermal conductivity.

As a high thermal conductive 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 is expected to solve the above problems, and that the cured product exhibits effects in terms of thermal conductivity and heat resistance. I found

（但し、Ｘは、独立して、直接結合、酸素原子、硫黄原子、－ＳＯ₂－、－ＣＯ－、－ＣＯＯ－、－ＣＯＮＨ－、－ＣＨ₂－又は－Ｃ（ＣＨ₃）₂－を示し、ｎは０～１５の数を示す。） That is, the present invention is an epoxy resin represented by the following general formula (1), characterized by having an epoxy equivalent of 230 to 350 g/eq and a softening point of 130° C. or less.

(where X is independently a direct bond, an oxygen atom, a sulfur atom, -SO ₂ -, -CO-, -COO-, -CONH-, -CH ₂ - or -C(CH ₃ ) ₂ - and n is a number from 0 to 15.)

In the above general formula (1), it is preferable that the area % (GPC area %) measured by gel permeation chromatography, where n=0, is 40% or less.

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 and excellent solvent solubility. Suitable for The cured product has excellent heat resistance, thermal decomposition stability, and thermal conductivity, and is therefore suitable for sealing electric/electronic parts, circuit board materials, and the like.

1 is a GPC chart of the epoxy resin obtained in Example 1. FIG.

The present invention will be described in detail below.

Ｘは、独立して、直接結合、酸素原子、硫黄原子、－ＳＯ₂－、－ＣＯ－、－ＣＯＯ－、－ＣＯＮＨ－、－ＣＨ₂－又は－Ｃ（ＣＨ₃）₂－を示し、ｎは０～１５の数を示す。高熱伝導性の点で、Ｘは直接結合であるビフェニル構造、－ＳＯ₂－、－ＣＯ－、－ＣＯＯ－、－ＣＯＮＨ－が好ましく、４，４’位のビフェニル構造が特に好ましい。一方、成型性、溶剤溶解性の点で、酸素原子、硫黄原子、－ＣＨ₂－、－Ｃ（ＣＨ₃）₂－が好ましい。その際、前記「独立して」としたように、本発明の式（１）のエポキシ樹脂は、Ｘが異なる構造の混合物とすることことが可能であり、高熱伝導性、成型性、溶剤溶解性を調整することが可能である。なお、当該Ｘに直接結合（ビフェニル構造）が含まれる場合には、高熱伝導性、成型性、溶剤溶解性などの調整の観点から、そのＸの全てが直接結合ではないことが好ましい。なお、Ｘに直接結合が含まれる場合には、その含有量は、原料化合物の質量に基づいて、７０質量％以下が好ましく、３０質量％～７０質量％であることがより好ましい。 First, the present invention is an epoxy resin represented by general formula (1), characterized by having an epoxy equivalent of 230 to 350 g/eq and a softening point of 130° C. or less.

X is independently a direct bond, an oxygen atom, a sulfur atom, -SO ₂ -, -CO-, -COO-, -CONH-, -CH ₂ - or -C(CH ₃ ) ₂ -; indicates a number from 0 to 15. From the viewpoint of high thermal conductivity, X is preferably a direct bond biphenyl structure, --SO ₂ --, --CO--, --COO--, --CONH--, and particularly preferably a biphenyl structure at the 4,4'-positions. 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. It is possible to adjust gender. In addition, when the X includes a direct bond (biphenyl structure), it is preferable that not all of the X is a direct bond from the viewpoint of adjusting high thermal conductivity, moldability, solvent solubility, and the like. When X contains a direct bond, its content is preferably 70% by mass or less, more preferably 30% to 70% by mass, based on the mass of the raw material compound.

n is the number of repetitions (number average) and represents a number from 0 to 15; Preferred are mixtures of components with different values of n. In addition, the area % (GPC area %) measured by gel permeation chromatography, where n=0, is preferably 40% or less. More preferably, it is 30% or less. If the n=0 content is more than 40%, the crystallinity is strong, the melting point is 130° C. or higher, and the solvent solubility tends to decrease. On the other hand, when n is larger than 15, the reactivity is low, and if unreacted components are generated during curing, the heat resistance is lowered.

The softening point of the epoxy resin of the present invention is in the range of 130° C. or lower. If the temperature is higher than 130°C, the melt-kneadability is lowered, and if it has crystallinity, the solvent solubility is also lowered. In applications and fields where it is preferable to prevent blocking due to stickiness, such as sealing material applications, the softening point should not be too low. ~110°C.

The epoxy equivalent weight of the epoxy resin of the present invention is in the range of 230-350. If it exceeds this range, the reactivity is low, and unreacted components are produced during curing, resulting in deterioration of heat resistance and reliability. If it is less than this range, it indicates that the bifunctional epoxy resin component that does not contain a benzonitrile structure increases. When the amount of resin is large, the heat resistance and thermal conductivity of the cured product are lowered.

（但し、Ｘは、独立して、直接結合、酸素原子、硫黄原子、－ＳＯ₂－、－ＣＯ－、－ＣＯＯ－、－ＣＯＮＨ－、－ＣＨ₂－又は－Ｃ（ＣＨ₃）₂－を示し、ｎは０～１５の数を示す。）
式（２）で表されるフェノール性化合物は、水酸基当量（ｇ／ｅｑ）が、好ましくは１１５０～２５０、より好ましくは１８０～２３０である。また、融点が、好ましくは１４０℃～３００℃、より好ましくは１５０℃～２８０℃である。 The method for producing the epoxy resin of the present invention is not particularly limited, but it can be produced by reacting a phenolic compound having a benzonitrile structure of the following formula (2) with epichlorohydrin. This reaction can be carried out in the same manner as a normal epoxidation reaction.

(where X is independently a direct bond, an oxygen atom, a sulfur atom, -SO ₂ -, -CO-, -COO-, -CONH-, -CH ₂ - or -C(CH ₃ ) ₂ - and n is a number from 0 to 15.)
The phenolic compound represented by formula (2) has a hydroxyl equivalent (g/eq) of preferably 1150-250, more preferably 180-230. Also, the melting point is preferably 140°C to 300°C, more preferably 150°C to 280°C.

Here, the phenolic compound represented by formula (2) is not limited, but examples include 2,4-dichlorobenzonitrile, 2,5-dichlorobenzonitrile, 2,6-dichlorobenzonitrile, 3, For benzonitrile compounds such as 5-dichlorobenzonitrile, 2,4-dibromobenzonitrile, 2,5-dibromobenzonitrile, 2,6-dibromobenzonitrile, 3,5-dibromobenzonitrile, 4,4' -dihydroxybiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxybenzophenone, bisphenol A, bisphenol F, etc. It can be obtained by a method of reacting a dihydroxy compound possessed in the presence of a basic catalyst.

The reaction between the phenolic compound of formula (2) and epichlorohydrin can be carried out, for example, by dissolving the phenolic compound in an excess of epichlorohydrin and then reacting it in the presence of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide. A method of reacting at 150° C., preferably at 60 to 100° C. for 1 to 10 hours 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 a phenolic compound having a benzonitrile structure and another phenolic compound having no benzonitrile structure. In this case, the mixing ratio of the phenolic compound having a benzonitrile structure is 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 the epoxy resin having a benzonitrile structure, 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 having a benzonitrile structure of formula (1) used as an essential component, other epoxy resins having two or more epoxy groups in the molecule are added as epoxy resin components. They may be used together. 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 proportion of the epoxy resin having a benzonitrile structure of formula (1) used in the epoxy resin composition of the present invention is 50 wt% or more, preferably 70 wt% or more, and 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 having a benzonitrile structure 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 mixing 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, scaly pigments, and the like. 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, if 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 heptadecylimidazole; 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.

The resin cured product of the present invention can be obtained by heat-curing the epoxy resin composition of the present invention. 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.

EXAMPLES 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 column (TSKgelG4000HXL, TSKgelG3000HXL, TSKgelG2000HXL, manufactured by Tosoh Corporation) in series with a main body (HLC-8220GPC manufactured by Tosoh Corporation) was used, and the column temperature was set to 40°C. Tetrahydrofuran (THF) was used as an eluent at a flow rate of 1 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 (EXSTAR6000TMA/6100 manufactured by SII Nanotechnology Co., Ltd.).

8) 5% weight loss temperature (Td5), residual carbon ratio Using a thermogravimetric/differential thermal analyzer (EXSTAR6000TG/DTA6200, manufactured by SII Nanotechnology), under a nitrogen atmosphere, at a heating rate of 10°C/min. , 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.

Example 1
After dissolving 54.6 g of 4,4'-dihydroxybiphenyl and 29.6 g of 4,4'-dihydroxydiphenyl ether in 250 g of N-methyl-2-pyrrolidone in a 2 L four-necked separable flask, 24.1 g of potassium carbonate was added. The temperature was raised to 120° C. under a nitrogen stream while stirring. After that, 25.2 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 20.9 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 distillation under reduced pressure to obtain 84 g of hydroxy resin. The hydroxyl equivalent of the obtained hydroxy resin was 195 g/eq. , a melting point of 235° C. and an Mn of 500.
Next, 800 g of epichlorohydrin and 160 g of diethylene glycol dimethyl ether were added to 84 g of the obtained hydroxy resin, and 37.5 g of a 48% sodium hydroxide aqueous 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, methyl isobutyl ketone was distilled off under reduced pressure, and 105 g of epoxy resin solid at room temperature was obtained ( Epoxy resin A). The obtained epoxy resin A had a softening point of 113° C. and an epoxy equivalent of 251 g/eq. , the melt viscosity was 0.06 Pa·s, the n = 0 body measured by GPC was 30%, and the Mn was 460.

Example 2
The reaction was carried out in the same manner as in Example 1 except that the amount of 4,4'-dihydroxybiphenyl used was changed to 40.9 g and the amount of 4,4'-dihydroxydiphenyl ether used was changed to 44.4 g to obtain 112 g of an epoxy resin. (epoxy resin B). The obtained epoxy resin B had a softening point of 104° C. and an epoxy equivalent of 241 g/eq. , the melt viscosity was 0.04 Pa·s, the n = 0 body measured by GPC was 23%, and the Mn was 590. Incidentally, the hydroxyl equivalent of the intermediate hydroxy resin was 184 g/eq. , a melting point of 221° C. and an Mn of 670.

Example 3
The amount of 4,4'-dihydroxybiphenyl used was 54.5 g, and instead of 4,4'-dihydroxydiphenyl ether, dihydroxydiphenylmethane (4,4'-dihydroxydiphenylmethane: 36.2%, 2,4'-dihydroxydiphenylmethane: 46 6%, 2,2'-dihydroxydiphenylmethane: 17.2%) was used, but the reaction was carried out in the same manner as in Example 1 to obtain 96 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 264 g/eq. , the melt viscosity was 0.06 Pa·s, the n = 0 body measured by GPC was 28%, and the Mn was 480. Incidentally, the hydroxyl group equivalent of the intermediate hydroxy resin was 193 g/eq. , a melting point of 276° C. and an Mn of 540.

Example 4
The amount of 4,4'-dihydroxybiphenyl used was 40.9 g, and instead of 4,4'-dihydroxydiphenyl ether, dihydroxydiphenylmethane (4,4'-dihydroxydiphenylmethane: 36.2%, 2,4'-dihydroxydiphenylmethane: 46 .6%, 2,2'-dihydroxydiphenylmethane: 17.2%) was changed to 43.6 g, but the reaction was carried out in the same manner as in Example 1 to obtain 98 g of an epoxy resin. (epoxy resin D). The obtained epoxy resin D had a softening point of 109° C. and an epoxy equivalent of 250 g/eq. , the melt viscosity was 0.05 Pa·s, the n = 0 body measured by GPC was 29%, and the Mn was 630. Incidentally, the hydroxyl group equivalent of the intermediate hydroxy resin was 205 g/eq. , a melting point of 255° C. and an Mn of 540.

Example 5
The reaction was carried out in the same manner as in Example 1 except that 4,4'-dihydroxybiphenyl was not used and the amount of 4,4'-dihydroxydiphenyl ether used was changed to 88.8 g to obtain 107 g of an epoxy resin. (epoxy resin E). The obtained epoxy resin E had a softening point of 50° C. and an epoxy equivalent of 258 g/eq. , the melt viscosity was 0.03 Pa·s, the n = 0 body measured by GPC was 28%, and the Mn was 540. Incidentally, the hydroxyl group equivalent of the intermediate hydroxy resin was 202 g/eq. , a melting point of 157° C. and an Mn of 600.

Comparative example 1
Example 1 was repeated except that the amount of 4,4'-dihydroxybiphenyl used was 81.8 g, 4,4'-dihydroxydiphenyl ether was not used, and N-methyl-2-pyrrolidone was used in an amount of 500 g. 78 g of epoxy resin was obtained. (epoxy resin F). The obtained epoxy resin F has crystallinity, has 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.

Examples 6-10 and Comparative Examples 2-4
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 Example 5 were used. Epoxy resin E obtained in Comparative Example 1, epoxy resin F obtained in Comparative Example 1, epoxy resin G (4,4'-dihydroxydiphenyl ether type epoxy resin, epoxy equivalent 163 g / eq.; YSLV-80XY, manufactured by Nippon Steel Chemical & Material) and epoxy Using resin H (biphenyl type epoxy resin, epoxy equivalent 195 g / eq.; YX-4000H, manufactured by Mitsubishi Chemical), as a curing agent, phenol novolak resin (OH equivalent 105, softening point 83 ° C.; BRG-557, Aica Kogyo (manufactured) and triphenylphosphine as a curing accelerator to obtain an epoxy resin composition with the formulation shown in Table 1. 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.

Claims (4)

An epoxy resin represented by the following general formula (1) having an epoxy equivalent of 230 to 350 g/eq and a softening point of 130° C. or less.

(where X is independently a direct bond, an oxygen atom, a sulfur atom, -SO ₂ -, -CO-, -COO-, -CONH-, -CH ₂ - or -C(CH ₃ ) ₂ - and n is a number from 0 to 15.) 2. The epoxy resin according to claim 1, wherein the area % (GPC area %) measured by gel permeation chromatography contains 40% or less of the component where n=0. An epoxy resin composition comprising the epoxy resin according to claim 1 or 2 as an essential component. A cured epoxy resin obtained by curing the epoxy resin composition according to claim 3 .

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