JP4813201B2 - Indole skeleton-containing epoxy resin, epoxy resin composition and cured product thereof - Google Patents

Description

  The present invention relates to an epoxy resin that gives a cured product that is excellent in flame retardancy and also has excellent moisture resistance, heat resistance, adhesion to a metal substrate, and the like, and an epoxy resin composition and a cured product thereof. And is suitably used for insulating materials in the electrical and electronic fields such as printed wiring boards and semiconductor encapsulation.

  Epoxy resins have been used in a wide range of industrial applications, but their required performance has become increasingly sophisticated in recent years. For example, there is a semiconductor sealing material in a typical field of a resin composition mainly composed of an epoxy resin, but as the integration degree of semiconductor elements is improved, the package size is becoming larger and thinner, and the mounting method is also increased. The transition to surface mounting is progressing, and the development of materials with excellent solder heat resistance is desired. Therefore, as a sealing material, in addition to reducing moisture absorption, improvement in adhesion and adhesion at the interface between different materials such as lead frames and chips is strongly demanded. Similarly, for circuit board materials, in addition to improving low heat absorption, high heat resistance, and high adhesion from the viewpoint of improving solder heat resistance, it is desirable to develop materials with excellent low dielectric properties from the viewpoint of reducing dielectric loss. Yes. In order to meet these demands, various new structures of epoxy resins have been studied from the epoxy resin side as the main agent. Furthermore, recently, from the viewpoint of reducing the environmental load, there has been a movement to eliminate halogen-based flame retardants, and there is a demand for epoxy resins with better flame retardancy.

  However, no conventionally known epoxy resins satisfy these requirements. For example, the well-known bisphenol type epoxy resin is in a liquid state at room temperature and is widely used because it is excellent in workability and easy to mix with a curing agent, an additive, etc. There is a problem in terms of moisture resistance. Further, novolak type epoxy resins are known as improved heat resistance, but there are problems in moisture resistance, adhesion and the like. Furthermore, the conventional epoxy resin whose main skeleton is composed of only hydrocarbons has no flame retardancy.

  As a measure for improving flame retardancy without using a halogen flame retardant, a method of adding a phosphate ester flame retardant is disclosed in JP-A-9-235449, JP-A-10-182792, and the like. Has been. However, the method using a phosphate ester flame retardant does not have sufficient moisture resistance. In addition, the phosphoric acid ester is hydrolyzed under a high temperature and humidity environment, and there is a problem that the reliability as an insulating material is lowered.

JP-A-11-140166 JP 2004-57992 A Japanese Patent Laid-Open No. 4-173831 JP 2000-129092 A Japanese Patent Laid-Open No. 3-90075 JP-A-3-281623

  Patent Documents 1, 3, and 4 disclose examples in which an aralkyl epoxy resin having a biphenyl structure is applied to a semiconductor encapsulant as a material that improves flame retardancy without containing phosphorus atoms or halogen atoms. Patent Document 2 discloses an example in which an aralkyl type epoxy resin having a naphthalene structure is used. However, these epoxy resins have insufficient performance in any of flame retardancy, moisture resistance, and heat resistance. Patent Documents 5 and 6 disclose a naphthol-based aralkyl epoxy resin and a semiconductor sealing material containing the naphthol-based aralkyl epoxy resin, but nothing focuses on flame retardancy.

  The object of the present invention is excellent in flame retardancy and also has excellent performance in moisture resistance, heat resistance, adhesion to a metal substrate, etc., and is useful for applications such as lamination, molding, casting and adhesion. An object is to provide an epoxy resin, a curing agent, an epoxy resin composition using them, and a cured product thereof.

で表される基のいずれかであり、Ｒ₁は水素原子、グリシジルオキシ基、炭素数１〜８のアルコキシ基、ハロゲン原子又は炭素数１〜８の炭化水素基を示し、Ａは炭素数１〜８のアルキル基若しくはグリシジルオキシ基が置換してもよいベンゼン環からなる基、又は炭素数１〜８のアルキル基若しくはグリシジルオキシ基が置換してもよいナフタレン環からなる基を示し、式（２）と式（３）で表される基の存在割合（モル比）が１：９〜２：８の範囲であり、Ｘは下記式（ａ）又は式（ｂ）

で表される架橋基であり、Ｒ₂、Ｒ₃、Ｒ₄及びＲ₅は独立に、水素原子又は炭素数１〜６の炭化水素基を示し、Ｂはベンゼン環、ビフェニル環又はナフタレン環からなる基を示し、ｎは１〜１０の数を示し、Ｙは水素原子、炭素数１〜８の炭化水素基又はグリシジル基を示し、Ｇはグリシジル基を示す。）で表されるインドール骨格含有エポキシ樹脂である。 That is, the present invention provides the following general formula (1)
HL- (XL) _n -H (1)
(Where L is the following formula (2) and formula (3)

R ₁ represents a hydrogen atom, a glycidyloxy group, an alkoxy group having 1 to 8 carbon atoms, a halogen atom, or a hydrocarbon group having 1 to 8 carbon atoms, and A represents a carbon number of 1 A group consisting of a benzene ring which may be substituted by an alkyl group or a glycidyloxy group of ˜8 , or a group consisting of a naphthalene ring which an alkyl group or a glycidyloxy group having 1 to 8 carbon atoms may be substituted ; 2) and the ratio (molar ratio) of the groups represented by formula (3) is in the range of 1: 9 to 2: 8 , and X is the following formula (a) or formula (b):

R ₂ , R ₃ , R ₄ and R ₅ independently represent a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, and B represents a benzene ring, a biphenyl ring or a naphthalene ring. N represents a number of 1 to 10, Y represents a hydrogen atom, a hydrocarbon group having 1 to 8 carbon atoms or a glycidyl group, and G represents a glycidyl group. ) -Containing epoxy resin containing indole skeleton.

Moreover, this invention is an epoxy resin composition formed by mix | blending the said epoxy resin as an essential component in the epoxy resin composition which consists of an epoxy resin and a hardening | curing agent.
Furthermore, the present invention is a cured product obtained by curing the epoxy resin composition.

で表される基のいずれかであり、Ｒ'₁は水素原子、水酸基、炭素数１〜８のアルコキシ基、ハロゲン原子又は炭素数１〜８の炭化水素基を示し、Ａは炭素数１〜８のアルキル基若しくは水酸基が置換してもよいベンゼン環又はナフタレン環からなる基を示し、Ｘ及びｎは式（１）〜（３）と同じ意味を有する。）で表されるインドール骨格含有ヒドロキシ樹脂と、エピクロルヒドリンを反応させることを特徴とする製造方法である。 Moreover, the present invention provides the method for producing an epoxy resin according to claim 1, wherein the following general formula (1 ′)
H-L '-(X-L') _n -H (1 ')
(Here, L ′ is the following formula (2 ′) and formula (3 ′)

R ′ ₁ represents a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 8 carbon atoms, a halogen atom, or a hydrocarbon group having 1 to 8 carbon atoms, and A represents a group having 1 to 1 carbon atoms. 8 represents a group consisting of a benzene ring or a naphthalene ring which may be substituted by an alkyl group or a hydroxyl group, and X and n have the same meanings as in the formulas (1) to (3). The indole skeleton-containing hydroxy resin represented by (II) is reacted with epichlorohydrin.

  In the above general formula (1), L is a group selected from the groups represented by formula (2) and formula (3), and the abundance ratio thereof is 1: 9 to 9: 1, preferably 3: 7 to 7 : 3. X is a group represented by formula (a) or formula (b), and n is a number from 1 to 10. Here, n + 1 L and n X in the formula (1) may be the same or different from each other, but L is the above-mentioned ratio in the resin in the formula (2) and the formula ( There is a group represented by 3). However, since the resin is a mixture, it may be present as an average. Y is a group represented by a hydrogen atom, a hydrocarbon group having 1 to 8 carbon atoms or a glycidyl group, and these may be the same group at the same time, or a hydrogen atom, a hydrocarbon group, a glycidyl group. May coexist. The abundance ratio of glycidyl groups is 0 to 100%, and in heat resistance, the higher the abundance ratio of glycidyl groups, the better. In addition, in terms of flame retardancy, the lower the proportion of glycidyl groups, the better, preferably 0 to 50%, and even more preferably all hydrogen atoms.

In Formula (2) and Formula (3), R ₁ represents a hydrogen atom, an alkoxy group having 1 to 8 carbon atoms, a glycidyloxy group, a halogen atom, or a hydrocarbon group having 1 to 8 carbon atoms. Here, examples of the alkoxy group include a methoxy group, an ethoxy group, a vinyl ether group, an isopropoxy group, an allyloxy group, a propargyl ether group, a putoxy group, a phenoxy group, and a benzyloxy group. The halogen atom includes a fluorine atom, a chlorine atom, Examples include bromine atoms. The hydrocarbon groups include methyl, ethyl, vinyl, ethyne, n-propyl, isopropyl, allyl, propargyl, n-butyl, sec-butyl, tert-butyl, n- Examples include amyl group, sec-amyl group, tert-amyl group, cyclohexyl group, phenyl group, benzyl group and the like. A is a group produced by epoxidizing phenols (which may be polyhydric phenols or polycyclic aromatic phenols), and n is a number of 1 to 10. In addition, although resin is a mixture, it is good for n of the average (number average) to also exist in the said range.

X is a bridging group represented by formula (a) or formula (b), but R ₂ , R ₃ , R ₄ and R ₅ independently represent a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. , B represents a group consisting of a benzene ring, a biphenyl ring or a naphthalene ring. Here, examples of the hydrocarbon group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a butyl group, an amyl group, and a phenyl group. Preferred examples of the crosslinking group of the formula (a) include a methylene group, an ethylidene group, an isopropylidene group, and a phenylmethylene group. Preferred examples of the crosslinking group of the general formula (b) include a p-xylylene group, an m-xylylene group, 1,4-bisethylidenephenylene group, 1,3-bisethylidenephenylene group, 1,4-bisisopropylidenephenylene group, 1,3-bisisopropylidenephenylene group, 4,4′-bismethylenebiphenyl group, 3, 4′-bismethylenebiphenyl group, 3,3′-bismethylenebiphenyl group, 4,4′-bisethylidenebiphenyl group, 3,4′-bisethylidenebiphenyl group, 3,3′-bisethylidenebiphenyl group, 4, 4'-bisisopropylidenebiphenyl group, 3,4'-bisisopropylidenebiphenyl group, 3,3'-bisisopropylide Biphenyl group, 1,4-bismethylenenaphthalene group, 1,5-bismethylenenaphthalene group, 1,6-bismethylenenaphthalene group, 2,7-bismethylenenaphthalene group, 1,4-bisethylidenenaphthalene group, 1, 5-bisethylidenenaphthalene group, 1,6-bisethylidenenaphthalene group, 2,7-bisethylidenenaphthalene group, 1,4-bisisopropylidenenaphthalene group, 1,5-bisisopropylidenenaphthalene group, 1,6-bis Examples thereof include isopropylidenenaphthalene group and 2,7-bisisopropylidenenaphthalene group. X bridges L, but the substitution position of X with respect to the groups represented by the formulas (2) and (3) constituting L is not particularly limited. For example, the 1-position to the 7-position of the indole ring The hydrogen atom is substituted with a bridging group to form a linked structure, but if the nitrogen atom at the 1-position of all indole rings is substituted with a bridging group, the curability and heat resistance are reduced, The function as an epoxy resin is not sufficiently exhibited.

The epoxy resin of the present invention is advantageously produced by reacting the indole skeleton-containing hydroxy resin represented by the general formula (1 ′) with epichlorohydrin, but is not limited to this reaction. The indole skeleton-containing hydroxy resin represented by the general formula (1 ′) is a resin in which at least a part, preferably all, of the site epoxidized with epichlorohydrin is H or OH. In (1) to (3), the site that is a glycidyl ether group is OH, and the site that is a glycidyl group is H. In addition, in general formula (1), it is advantageous in terms of flame retardancy to epoxidize such that a part of Y is H and a part is a glycidyl group.
In addition to the reaction of reacting the indole skeleton-containing hydroxy resin with epichlorohydrin, the indole skeleton-containing hydroxy resin represented by the general formula (1 ′) is reacted with an allyl halide to form an allyl ether compound, which is then reacted with a peroxide. You can also take the method. The reaction of reacting the indole skeleton-containing hydroxy resin with epichlorohydrin can be carried out in the same manner as a normal epoxidation reaction.

  For example, after the above indole skeleton-containing hydroxy resin is dissolved in excess epichlorohydrin, it is in the range of 20 to 150 ° C., preferably 30 to 80 ° C. in the presence of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide. And reacting for 1 to 10 hours. The amount of alkali metal hydroxide used in this case is in the range of 0.8 to 1.5 mol, preferably 0.9 to 1.2 mol, based on 1 mol of the hydroxyl group of the indole skeleton-containing hydroxy resin. . Epichlorohydrin is used in an excess amount relative to 1 mol of hydroxyl group in the indole skeleton-containing hydroxy resin, but is usually 1.5 to 30 mol, preferably 2 to 1 mol of hydroxyl group in the indole skeleton-containing hydroxy resin. The range is ˜15 mol. After completion of the reaction, excess epichlorohydrin is distilled off, the residue is dissolved in a solvent such as toluene, methyl isobutyl ketone, filtered, washed with water to remove inorganic salts, and then the target epoxy is removed by distilling off the solvent. A resin can be obtained. Although most, preferably all, of the hydroxy groups are epoxidized by this reaction, it is preferable to epoxidize a part of the NH groups having poor reactivity.

  The epoxy resin composition of the present invention is an epoxy resin composition comprising an epoxy resin and a curing agent, and contains an epoxy resin represented by the above general formula (1) as an essential component as an epoxy resin component.

  As the curing agent when the epoxy resin represented by the general formula (1) is an essential component, any of those generally known as curing agents for epoxy resins can be used. Examples include dicyandiamide, polyhydric phenols, acid anhydrides, aromatic and aliphatic amines. Specifically, as polyhydric phenols, for example, bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4′-biphenol, 2,2′-biphenol, hydroquinone, resorcin, naphthalenediol, etc. Divalent phenols; or tris- (4-hydroxyphenyl) methane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, phenol novolak, o-cresol novolak, naphthol novolak, polyvinylphenol, etc. There are representative trihydric or higher phenols. Furthermore, monovalent or divalent such as phenols, naphthols, bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4′-biphenol, 2,2′-biphenol, hydroquinone, resorcin, naphthalenediol, etc. Examples include phenols and polyhydric phenolic compounds synthesized by a condensing agent such as formaldehyde, acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde, salicylaldehyde, and p-xylylene glycol. In addition, an indole skeleton-containing hydroxy resin represented by the general formula (1 ') is also preferably exemplified.

  Examples of the acid anhydride include phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyl hymic anhydride, nadic anhydride, and trimellitic anhydride.

Examples of amines 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.
In the resin composition of the present invention, one or more of these curing agents can be mixed and used.

  Moreover, you may mix | blend another kind of epoxy resin other than the epoxy resin of this invention represented by General formula (1) as an epoxy resin component in the epoxy resin composition of this invention. As the epoxy resin in this case, all ordinary epoxy resins having two or more epoxy groups in the molecule can be used. Examples include divalent phenols such as bisphenol A, bisphenol S, fluorene bisphenol, 4,4′-biphenol, 2,2′-biphenol, hydroquinone, resorcin, or tris- (4-hydroxyphenyl) methane. , 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, phenol novolac, o-cresol novolak, and more trivalent phenols, phenol-based aralkyl resins, naphthol-based aralkyl resins, or tetrabromobisphenol There are glycidyl ethers derived from halogenated bisphenols such as A. These epoxy resins can be used alone or in combination of two or more. And in the case of the composition which has the epoxy resin of this invention as an essential component, the compounding quantity of the epoxy resin represented by General formula (1) in connection with this invention is 5-100% in the whole epoxy resin, Preferably it is 60- A range of 100% is preferable.

  In addition, the epoxy resin composition of the present invention may be appropriately mixed with an oligomer or a polymer compound such as polyester, polyamide, polyimide, polyether, polyurethane, petroleum resin, indene coumarone resin, phenoxy resin, etc. You may mix | blend additives, such as a filler, a pigment, a refractory agent, a thixotropic agent, a coupling agent, and a fluidity improver. Examples of the inorganic filler include spherical or crushed fused silica, silica powder such as crystalline silica, alumina powder, glass powder, mica, talc, calcium carbonate, alumina, hydrated alumina, and the like. A preferable blending amount when used for a sealing material is 70 wt% or more, and more preferably 80 wt% or more.

  Examples of the pigment 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.

  Further, if necessary, the resin composition of the present invention includes a release agent such as carnauba wax and OP wax, a coupling agent such as γ-glycidoxypropyltrimethoxysilane, a colorant such as carbon black, and trioxide. Flame retardants such as antimony, low stress agents such as silicone oil, lubricants such as calcium stearate, etc. can be used.

  Furthermore, 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., specifically 1,8-diazabicyclo (5,4,0) undecene-7, triethylenediamine, benzyldimethylamine, 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, addition reaction products of organic phosphines and quinone compounds, tetraphenylphosphine Tetra-substituted phosphonium / tetra-substituted borate such as phonium / tetraphenylborate, tetraphenylphosphonium / ethyltriphenylborate, tetrabutylphosphonium / tetrabutylborate, 2-ethyl-4-methylimidazole / tetraphenylborate, N-methylmorpholine / Examples include tetraphenylboron salts such as tetraphenylborate. The addition amount is usually in the range of 0.2 to 5 parts by weight with respect to 100 parts by weight of the epoxy resin.

  The epoxy resin composition of the present invention is made into a varnish in which an organic solvent is dissolved, and then impregnated into a fibrous material such as a glass cloth, an aramid nonwoven fabric, a polyester nonwoven fabric such as a liquid crystal polymer, and then the solvent is removed. can do. Moreover, it can be set as a laminated body by apply | coating on sheet-like materials, such as copper foil, stainless steel foil, a polyimide film, and a polyester film depending on the case.

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

  If the epoxy resin composition of the present invention is cured by heating, an epoxy resin cured product can be obtained. This cured product is excellent in terms of flame retardancy, low moisture absorption, high heat resistance, adhesion, and the like. It can be suitably used for applications such as sealing of electric / electronic parts, circuit board materials, and the like.

Hereinafter, the present invention will be described more specifically with reference to examples.
Here, the viscosity was measured using a B-type viscometer, and the softening point was measured by the ring and ball method according to JIS K-6911. The GPC measurement conditions were as follows: apparatus: HLC-82A (manufactured by Tosoh Corp.), column: TSK-GEL2000 × 3 and TSK-GEL4000 × 1 (both manufactured by Tosoh Corp.), solvent: tetrahydrofuran, flow rate 1 ml / min, temperature; 38 ° C., detector; RI; polystyrene standard solution was used for the calibration curve.

Reference example 1
A 500 mL, 3-neck separable flask equipped with a stirrer, a condenser tube, and a nitrogen inlet tube was charged with 72.5 g of indole, 233.1 g of phenol, and 27.9 g of 92% paraformaldehyde, and the temperature was increased to 90 ° C. while introducing nitrogen. Heat to dissolve. Then, it heated up at 130 degreeC, stirring, and was made to react for 3 hours. During this time, water produced by the reaction was removed from the system. Thereafter, the temperature was raised to 180 ° C. under reduced pressure to remove condensed water, unreacted phenol and indole, thereby obtaining 150 g of an indole skeleton-containing hydroxy resin (indole resin A). The resulting resin had a softening point of 83 ° C., a melt viscosity at 150 ° C. of 0.12 Pa · s, and an OH equivalent of 208 g / eq. Met. The residual monomer amount determined by GPC measurement was 0.5 wt%.

Reference example 2
40.0 g of indole, 289.2 g of phenol, 257.4 g of 4,4′-bischloromethylbiphenyl and 147 g of monochlorobenzene were charged and heated to 80 ° C. and dissolved while introducing nitrogen. Then, it heated up to 150 degreeC, stirring under reduced pressure, and was made to react for 1 hour. During this time, hydrochloric acid and monochlorobenzene produced by the reaction were removed from the system. Thereafter, hydrochloric acid, unreacted phenol and indole were removed at 180 ° C. under reduced pressure to obtain 348.6 g of an indole skeleton-containing hydroxy resin (indole resin B). The resulting resin had a softening point of 94 ° C. and a melt viscosity at 150 ° C. of 0.93 Pa · s. The residual monomer amount determined by GPC measurement was 0.5 wt%.

Example 1
100 g of indole resin A obtained in Reference Example 1 was dissolved in 178 g of epichlorohydrin and 36 g of diethylene glycol dimethyl ether. Thereafter, 33.7 g of 96% potassium hydroxide was added over 3 hours at 50 ° C. with stirring, and the reaction was continued for another hour after the addition was completed. After completion of the reaction, the salt produced by filtration was removed, and after further washing with water, epichlorohydrin was distilled off to obtain 110 g of epoxy resin (epoxy resin A). The resulting epoxy resin had a softening point of 78 ° C., a melt viscosity of 0.28 Pa · s, and an epoxy equivalent of 278 g / eq. Met.

Examples 2-6 and Comparative Examples 1-3
As an epoxy resin component, the epoxy resin synthesized in Example 1, an o-cresol novolac type epoxy resin (epoxy resin B: Nippon Kayaku Co., Ltd., EOCN-1020-65; epoxy equivalent 200, hydrolyzable chlorine 400 ppm, softening point 65 Indole resin A synthesized in Reference Example 1 as a curing agent component using a biphenyl type epoxy resin (epoxy resin C: YE4000HK, epoxy equivalent 195, hydrolyzable chlorine 450 ppm, melting point 105 ° C.) , Phenol novolak (curing agent A: manufactured by Gunei Chemical Co., PSM-4261; OH equivalent 103, softening point 80 ° C.), 1-naphthol aralkyl type resin (curing agent B: manufactured by Nippon Steel Chemical Co., SN-475; OH equivalent) 210, softening point 77 ° C.). Furthermore, spherical silica (average particle size 18 μm) was used as a filler, triphenylphosphine was used as a curing accelerator, and an epoxy resin composition was obtained with the formulation shown in Table 1. The numerical value in a table | surface shows the weight part in a mixing | blending.

This epoxy resin composition was molded at 175 ° C., and further post-cured at 180 ° C. for 12 hours to obtain a cured product test piece, which was then subjected to various physical property measurements. The results are shown in Table 2.
In addition, the measurement of the glass transition point and the linear expansion coefficient was calculated | required with the temperature increase rate of 10 degree-C / min using the thermomechanical measuring apparatus. Further, the water absorption rate was defined as the rate of change in weight after absorbing moisture for 100 hours at 85 ° C. and 85% RH using a circular test piece having a diameter of 50 mm and a thickness of 3 mm. The burning time was expressed as the total burning time in five tests in accordance with UL94V-0 standard using a test piece having a thickness of 1/16 inch. The adhesive strength was obtained by molding a molded product of 25 mm × 12.5 mm × 0.5 mm between two copper plates at 175 ° C. with a compression molding machine, post-curing at 180 ° C. for 12 hours, and then adjusting the tensile shear strength. Evaluated by seeking.

Example 7
150 g of indole resin B obtained in Reference Example 2 was dissolved in 403 g of epichlorohydrin and 60 g of diethylene glycol dimethyl ether. Then, 48.9 g of 48.9% sodium hydroxide was added over 4 hours at 65 ° C. under reduced pressure with stirring, and the reaction was continued at 70 ° C. for 1 hour after the addition. After completion of the reaction, epichlorohydrin was distilled off under reduced pressure and then dissolved in MIBK. The salt produced by filtration was removed, and after further washing with water, MIBK was distilled off under reduced pressure to obtain 146 g of epoxy resin D. The resulting epoxy resin had a softening point of 83 ° C., a melt viscosity of 0.97 Pa · s, and an epoxy equivalent of 330 g / eq. Met.

Examples 8-11
As the epoxy resin component, the epoxy resin D synthesized in Example 7 was used, and the epoxy resin B, epoxy resin C, indole resin B, curing agent A, and curing agent B were further used. Moreover, the spherical resin (average particle diameter of 18 micrometers) was used as a filler, the triphenylphosphine was used as a hardening accelerator, and the epoxy resin composition was obtained by the mixing | blending shown in Table 3.

  This epoxy resin composition was molded at 175 ° C., and further post-cured at 180 ° C. for 12 hours to obtain a cured product test piece, which was then subjected to various physical property measurements. The results are shown in Table 4.

¹ H-NMR spectrum of epoxy resin A Infrared absorption spectrum of epoxy resin A GPC chart of epoxy resin A ¹ H-NMR spectrum of epoxy resin D Infrared absorption spectrum of epoxy resin D GPC chart of epoxy resin D

Claims (4)

The following general formula (1)
HL- (XL) _n -H (1)
(Where L is the following formula (2) and formula (3)

R ₁ represents a hydrogen atom, a glycidyloxy group, an alkoxy group having 1 to 8 carbon atoms, a halogen atom, or a hydrocarbon group having 1 to 8 carbon atoms, and A represents a carbon number of 1 A group consisting of a benzene ring which may be substituted by an alkyl group or a glycidyloxy group of ˜8 , or a group consisting of a naphthalene ring which an alkyl group or a glycidyloxy group having 1 to 8 carbon atoms may be substituted ; 2) and the ratio (molar ratio) of the groups represented by formula (3) is in the range of 1: 9 to 2: 8 , and X is the following formula (a) or formula (b):

R ₂ , R ₃ , R ₄ and R ₅ independently represent a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, and B represents a benzene ring, a biphenyl ring or a naphthalene ring. N represents a number of 1 to 10, Y represents a hydrogen atom, a hydrocarbon group having 1 to 8 carbon atoms or a glycidyl group, and G represents a glycidyl group. An indole skeleton-containing epoxy resin represented by   In the epoxy resin composition which consists of an epoxy resin and a hardening | curing agent, the epoxy resin composition formed by mix | blending the epoxy resin of Claim 1 as an essential component.   A cured product obtained by curing the epoxy resin composition according to claim 2. The method for producing an epoxy resin according to claim 1, wherein the following general formula (1 ')
H-L '-(X-L') _n -H (1 ')
(Here, L ′ is the following formula (2 ′) and formula (3 ′)

R ′ ₁ represents a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 8 carbon atoms, a halogen atom, or a hydrocarbon group having 1 to 8 carbon atoms, and A represents a group having 1 to 1 carbon atoms. 8 represents a group consisting of a benzene ring which may be substituted by an alkyl group or a hydroxyl group, or a group consisting of a naphthalene ring which may be substituted by an alkyl group having 1 to 8 carbon atoms or a hydroxyl group, and X and n are the formulas (1) ) Has the same meaning. The method for producing an epoxy resin comprising reacting an indole skeleton-containing hydroxy resin represented by formula (II) with epichlorohydrin.

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