JPH09176262A - Phenol-naphthol novolak condensate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the hygroscopicity and improve the heat resistance, mechanical properties, adhesiveness, filling properties, etc., to thereby realize the adaptation to, e.g. a curing agent for electrical and electronic industries by the condensation of a phenol compound and a naphthal compound with a biphenyl compound. SOLUTION: Phenol compounds (A) comprising a bisphenol compound obtained by the condensation of a compound of formula I (wherein R<1> is a 1-8C alkyl or a 1-8C alkoxy; and (i) is 1 to 3, and (j) is 0 to 2, provided that i+j<4) having at least one phenolic hydroxyl group on the noncondensed aromatic ring with an optionally halogen-substituted 1-8C aldehyde or ketone, or a biphenol compound of a structure wherein compounds of formula I are coupled and a compound (B) of formula II (wherein R<2> and R<3> are each a 1-8C alkyl or alkoxy; (k) is 1 to 3; and (p) and (q) are each 0 to 2) having at least one phenolic hydroxyl group on the naphthalene ring are subjected to condensation with a biphenyl compound (C) of formula III (wherein R<4> to R<9> are each H or a 1-8C alkyl; and X<1> and X<2> are each hydroxy, a halogen or a 1-8C alkoxy) in the presence of an acid catalyst for 1-7hr.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel phenol-naphthol novolak condensate and a curing agent for epoxy resins, which can be used as a binder for organic materials and inorganic materials and a curing agent for epoxy resins, and particularly in the electrical and electronic industries. For a phenol-naphthol novolac condensate excellent in low water absorption, heat resistance and the like, which is preferably used as a curing agent for epoxy resin for use as an epoxy resin for sealing electronic parts and laminate materials, and a curing agent for epoxy resin containing the same It is a thing.

[0002]

Epoxy resins are often used as resin materials for electronic materials, and various phenol novolac condensates, amines, and acid anhydrides are used as curing agents for the epoxy resins. Particularly, as a curing agent for epoxy resin for semiconductor (IC) encapsulation, a phenolic novolac condensate is mainly used in terms of heat resistance and reliability. In recent years, high integration of ICs, miniaturization and thinning of packages, and application of surface mounting method have been advanced, and the sealing material should further improve thermal shock resistance and soldering heat resistance during surface mounting work. Is required. A major factor affecting the heat resistance of soldering is the hygroscopicity of the sealing resin material. That is, the moisture-absorbed encapsulating material is inferior in soldering heat resistance because internal pressure is generated due to evaporation of water at high temperature during surface mounting work, internal peeling and package cracking occur. Therefore, it is particularly required that the phenolic novolac condensate used as the curing agent for the epoxy resin has low hygroscopicity. As a method of lowering the hygroscopicity of the sealing material, there is a method of increasing the amount of a non-hygroscopic filler such as silica to be filled in the sealing resin material as a filler. In this case, if the viscosity of the base resin material is high, the high filling property of the filler is impaired, so it is desirable that the viscosity of the phenolic novolac condensate used as the curing agent is low. Also,
The sealing material is required to have heat resistance, high strength, toughness, adhesive strength and the like. The conventional encapsulating resin material using a phenol novolac condensate as a curing agent for the encapsulating epoxy resin has relatively high hygroscopicity and is not sufficiently satisfactory in other physical properties.

Therefore, various phenolic novolac condensates have been proposed in order to improve low hygroscopicity, heat resistance, adhesiveness and the like. For example, novolac condensates using alkylphenols such as o-cresol, and 1
-There is a novolak condensate using naphthols such as naphthol (Japanese Patent Laid-Open No. 59-230017, Japanese Patent Laid-Open No. 5-1993).
78437 and JP-A-5-86156). Also,
A phenolic compound using di (hydroxypropyl) biphenyl as a phenol condensing agent has been disclosed (JP-A-5-117350). Further, some of the present inventors have proposed a phenol novolac condensate using a bis (methoxymethyl) biphenyl mixture (Japanese Patent Application No. 6-251328).

[0004]

However, even higher performance materials are desired. The object of the present invention is low hygroscopicity, heat resistance, mechanical properties, adhesiveness, excellent filling properties, etc., especially for the electric and electronic industries, for sealing electronic parts, and as a curing agent for epoxy resins for laminated plate materials. A novel phenol-naphthol novolak condensate which is preferably used and a curing agent for an epoxy resin containing the same are provided.

[0005]

That is, the present invention relates to a phenol-naphthol novolak condensate obtained by a condensation reaction of phenols and naphthols with a biphenyl compound.

Further, the present invention is a curing agent for epoxy resin, which comprises the above-mentioned phenol-naphthol novolac condensate.

The present invention further relates to an epoxy resin composition containing the above-mentioned phenol-naphthol novolac condensate and an epoxy resin, and a cured product thereof.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Phenols used in the present invention are compounds having at least one phenolic hydroxyl group on an aromatic ring which is not condensed. Specifically, a compound represented by the following formula (1):

[0009]

Embedded image (In the formula (1), R ¹ is an alkyl group having 1 to 8 carbon atoms or an alkoxy group having 1 to 8 carbon atoms, i is an integer of 1 to 3, and j is 0.
Indicates an integer of 2 and the sum of i and j is 4 or less. )

A bisphenol compound obtained by a condensation reaction of a compound of formula (1) with an aldehyde or ketone having 1 to 8 carbon atoms which may be substituted with halogen;
It is a biphenol compound having a structure in which the compound of formula (1) is coupled.

R ¹ is preferably an alkyl group having 1 to 8 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and more preferably an alkyl group having 1 to 8 carbon atoms. Further, i is preferably 1 to 2.

As the aldehyde or ketone having 1 to 8 carbon atoms which may be substituted with halogen, those having 1 to 4 carbon atoms which may be substituted with halogen are preferable. (Paraformaldehyde), acetaldehyde, acetone, methyl ethyl ketone, hexafluoroacetone and the like can be mentioned.

Specific examples of phenols include phenols such as phenol, resorcinol and hydroquinone, wherein j is 0; cresol, ethylphenol, n
-Propylphenol, iso-propylphenol,
Phenols in which j is 1 such as t-butylphenol, octylphenol and phenylphenol; phenols in which j is 2 such as xylenol, methylethylphenol, methylbutylphenol, methylhexylphenol, dipropylphenol, dibutylphenol, guaiacol and guetol. And biphenols such as biphenol; bisphenols such as bisphenol A and bisphenol F;

Among these, phenol, cresol, ethylphenol, n-propylphenol, iso-propylphenol, t-butylphenol, octylphenol, phenylphenol, xylenol, methylethylphenol, methylbutylphenol, methylhexylphenol, dipropylphenol, diphenol. Compounds in which i is 1, j is 0 to 2, R ¹ is an alkyl group having 1 to 8 carbon atoms, such as butylphenol, and bisphenols such as bisphenol A and bisphenol F are preferable. And these phenols may be individual or may be a mixture.

The naphthols used in the present invention are compounds having at least one phenolic hydroxyl group in the naphthalene ring represented by the following general formula (2).

[0016]

Embedded image (In the formula (2), R ² and R ³ represent an alkyl group having 1 to 8 carbon atoms or an alkoxy group having 1 to 8 carbon atoms, k is an integer of 1 to 3, and p and q are integers of 0 to 2. .)

R ² and R ³ preferably have 1 to 1 carbon atoms.
8 alkyl groups. k is preferably 1-2. As for p and q, the sum of p and q is preferably 3 or less.

Specific examples of naphthols are 1-naphthol, 2-naphthol, 1,6-naphthol, naphthoresorcin, α-naphthohydroquinone, β-naphthohydroquinone, naphthopyrogallol, methylnaphthol, ethylnaphthol, n-naphthol. Propylnaphthol, iso-propylnaphthol, t-butylnaphthol, octylnaphthol, methylethylnaphthol, methylpropylnaphthol, methylbutylnaphthol, methylhexylnaphthol, dimethylnaphthol, diethylnaphthol, dibutylnaphthol and the like can be mentioned. Among these, preferably, 1-naphthol, 2-naphthol, 1,6-naphthol, naphthoresorcin, α-naphthohydroquinone, β-
Naphthohydroquinone, with 1-naphthol and 2-naphthol being most preferred. These naphthols may be used alone or in a mixture.

The biphenyl compound used in the present invention is a compound represented by the following general formula (3).

[0020]

Embedded image (In the formula (3), R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ are hydrogen or an alkyl group having 1 to 8 carbon atoms, X ¹ and X ² are a hydroxyl group, halogen or 1 to 8 carbon atoms. 8 represents an alkoxy group.)

R ⁴ and R ⁵ are preferably hydrogen or a linear alkyl group having 1 to 8 carbon atoms, particularly preferably hydrogen or a linear alkyl group having 1 to 4 carbon atoms, and most preferably It is hydrogen. As R ⁶ , R ⁷ , R ⁸ and R ⁹ ,
It is preferably hydrogen or an alkyl group having 1 to 4 carbon atoms, and particularly preferably hydrogen. The halogen is preferably chlorine or bromine. X ¹ and X ² are preferably a hydroxyl group or an alkoxy group having 1 to 8 carbon atoms, and particularly preferably an alkoxy group having 1 to 4 carbon atoms.

Specific examples of the biphenyl compound include:
Bis (chloromethyl) biphenyl, bis (bromomethyl) biphenyl, bis (1-chloro-1-ethyl) biphenyl, bis (1-bromo-1-ethyl) biphenyl, bis (1-
Chloro-1-propyl) biphenyl, bis (1-bromo-1-
Propyl) biphenyl, bis (2-chloro-2-propyl)
Biphenyl, bis (2-bromo-2-propyl) biphenyl, bis (1-2chloro-1-2butyl) biphenyl, bis (1-2-bromo-1-butyl) biphenyl, bis (1
~ 4-chloro-1 ~ 4-heptyl) biphenyl, bis (1 ~ 4-
Bis (halogenoalkyl) biphenyls such as bromo-1-4-heptyl) biphenyl; bis (hydroxymethyl) biphenyl, bis (1-hydroxy-1-ethyl) biphenyl, bis (1-hydroxy-1-propyl) biphenyl, Bis (2-hydroxy-2-propyl) biphenyl, bis (1
~ 2-Hydroxy-1 -2 butyl) biphenyl, bis (1 ~
Bis (hydroxyalkyl) biphenyls such as 4-hydroxy-1--4-heptyl) biphenyl; bis (methoxymethyl) biphenyl, bis (1-methoxy-1-propyl) biphenyl, bis (2-methoxy-2-propyl) Biphenyl,
Bis (1-4-methoxy-1-4-heptyl) biphenyl, bis (ethoxymethyl) biphenyl, bis (1-ethoxy-1)
-Propyl) biphenyl, bis (2-ethoxy-2-propyl) biphenyl, bis (butoxymethyl) biphenyl,
Examples thereof include bis (alkoxyalkyl) biphenyls such as bis (1-2-butoxy-1-2-propyl) biphenyl. It should be noted that indications such as 1 to 4 correspond to 4-bromo-4-heptyl.

Of these, preferred are bis (methoxymethyl) biphenyl, bis (1-methoxy-1-propyl) biphenyl, bis (2-methoxy-2-propyl) biphenyl, bis (3-4-methoxy-3). ~ 4-heptyl) biphenyl, bis (ethoxymethyl) biphenyl, bis (1-
Ethoxy-1-propyl) biphenyl, bis (2-ethoxy)
Bis (alkoxyalkyl) biphenyls such as -2-propyl) biphenyl, bis (butoxymethyl) biphenyl and bis (1-2-butoxy-1-2-propyl) biphenyl. The biphenyl compound may be a single compound or a mixture.

The most preferred of the above-mentioned biphenyl compounds is bis (methoxymethyl) biphenyl, which is specifically represented by the following general formula (4).

[0025]

Embedded image

Bis (methoxymethyl) biphenyl has isomers represented by the following structural formulas (4a) to (4f).

[0027]

Embedded image

These bis (methoxymethyl) biphenyls can be produced, for example, by subjecting a halide of methoxymethylbenzene to a dehalogenation coupling reaction. The ratio of isomers in the product of this reaction is not particularly limited, but is generally 5a: 5b: 5c: 5d: 5e: 5.
f = (1) :( 0.2-0.6) :( 4-7) :( 0.
01-0.2) :( 0.1-2.0) :( 5-15). In the present invention, this reaction product can be used as it is. In addition, it is also possible to use those obtained by distilling and purifying and changing the ratio of isomers.

The phenol-naphthol novolak condensate of the present invention can be obtained by subjecting phenols and naphthols and a biphenyl compound to a condensation reaction in the presence of an acid catalyst for 1 to 7 hours.

In this case, the ratio of the total number of moles of phenols and naphthols to the number of moles of biphenyl compound is preferably 1: (0.1 to 1). The lower the molar ratio of the biphenyl compound is, the lower the viscosity of the condensate is obtained. However, when the ratio is less than 0.1, it is necessary to remove a large amount of unreacted phenols and naphthols, which is not economical. . Further, if the ratio exceeds 1, gelation occurs and it is not preferable as a practical condensate.

The molar ratio of phenols to naphthols used is (20-95) :( 80-5), preferably (40-90) :( 60-10), more preferably (60-85): (40 to 15). If the molar ratio of the naphthols is less than 5%, the effect of improving the hygroscopic property and heat resistance is small, and if the ratio exceeds 80%, the viscosity of the condensate increases excessively, which is not preferable.

Examples of the catalyst used in the condensation reaction include p-toluenesulfonic acid, sulfuric acid, dimethyl sulfate, diethyl sulfate and the like. The amount used is 0.1 to the total number of moles of phenols and naphthols.
It is preferably 0.01 times by mole. The reaction temperature is 120 to 190
C is preferred. If the temperature is lower than that, the reaction speed will be slow,
There are problems such as gelation at high temperatures.

The thus obtained phenol-naphthol novolak condensate of the present invention has a structure of the following formula.

[0034]

[Chemical 6] (In the formula, R ^{1 to} R ⁹ , i, j, k, p, and q have the same meanings as described above. M and n are integers of 0 to 20, but the average value is 0.
It is a larger natural number that is 10 or less. )

Since this phenol-naphthol novolac condensate has a phenolic hydroxyl group, it can be used as a curing agent for epoxy resins, like ordinary phenol novolac resins. A cured product of an epoxy resin using this phenol-naphthol novolak condensate as a curing agent is excellent in low hygroscopicity, heat resistance, mechanical properties, adhesiveness and flexibility.

As the epoxy resin used at this time,
For example, a bisphenol diglycidyl ether type epoxy resin obtained by adding an epoxy group to a bisphenol such as bisphenol A or bisphenol F; an epoxy group to a phenol novolac resin such as a normal phenol novolac resin, an orthocresol novolac resin and a brominated phenol novolac resin. Novolak type epoxy resin with glycidyl amine; glycidyl amine type epoxy resin such as diphenylmethane diamine tetraglycidyl ether, cyclohexane diamine tetraglycidyl ether; polyethylene glycol diglycidyl ether, epoxidized SB
R, aliphatic epoxy resins such as epoxidized soybean oil; 4,
4'-dihydroxybiphenyl and 3,3 ', 5,5'-
Dihydroxybiphenyl diglycidyl ether type epoxy resin obtained by adding an epoxy group to dihydroxybiphenyls such as tetramethyl-4,4′-dihydroxybiphenyl; polycyclic aromatic type epoxy resin such as 1,6-dihydroxynaphthalene diglycidyl ether Can be mentioned. Among these, novolac type epoxy resin, dihydroxybifevir diglycidyl ether type epoxy resin and polycyclic aromatic type epoxy resin are preferable, and novolac type epoxy resin is particularly preferable.

In order to obtain an epoxy resin cured product by using the phenol-naphthol novolac condensate of the present application as a curing agent, the ratio of the hydroxyl groups of the phenol-naphthol novolac condensate of the present application to the epoxy groups of the epoxy resin is approximately equal. So that this condensate and the above-mentioned epoxy resin are mixed to form an epoxy resin composition.
Heat to a degree. At this time, the epoxy resin composition preferably contains a curing accelerator generally used for promoting curing, such as N-methylimidazole, triethylamine and triphenylphosphine. Further, if necessary, various additives such as a filler, a coupling agent, a flame retardant, a lubricant, a release agent, a plasticizer, a colorant, a thickener and the like may be added.

Further, the phenol-naphthol novolac condensate of the present invention is cured by using a curing agent such as hexamethylenetetramine and aldehydes, and various adhesives, paints, sealing materials, friction materials, refractories, It can be used for molds and grindstones, and has excellent low hygroscopicity, heat resistance, mechanical properties,
Shows adhesiveness.

[0039]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited thereto.
In the following examples and comparative examples, "part" means "part by weight"
Means

Example 1 Phenol-naphthol novolac condensate (condensate A)
Synthesis of a mixture of a dropping funnel, a stirrer, a thermometer, and a flask equipped with a condenser 564 g (6 mol) of phenol, 173 g (1.2 mol) of 1-naphthol and a mixture of the general formula (4) (4a: 4b: 4c: 4d). : 4e: 4f = 1: 0.5:
5.5: 0.08: 0.3: 7.5) 484 g (2 mol) was charged, and diethyl sulfate 15.4 g (0.1 mol) was added.
Was added dropwise, and the mixture was stirred and the reaction temperature was maintained at 160 ° C.
Reacted for hours. The methanol produced during that time was distilled off. After completion of the reaction, the mixture was cooled and washed with water three times to separate an oil layer, and most of unreacted raw material monomers were distilled off by vacuum distillation to obtain 700 g of a condensate A. The resulting condensate A has a softening point of 74 ° C, a hydroxyl equivalent of 215 g / eq, and 150 ° C.
The melt viscosity at was 0.2 Pa · s.

Example 2 Phenol-naphthol novolac condensate (condensate B)
Synthesis of Example 1 In Example 1, 288 g of 1-naphthol (2 mol)
The same operation and reaction were performed except that the condensate B7 was used.
10 g were obtained. The resulting condensate B had a softening point of 78 ° C., a hydroxyl group equivalent of 220 g / eq, and a melt viscosity at 150 ° C. of 0.3 Pa · s.

Example 3 Phenol-naphthol novolac condensate (condensate C)
Synthesis of Example 1 In the same manner as in Example 1 except that 403 g (2.8 mol) of 1-naphthol was used, the same operation and reaction were carried out to obtain C720 g of a condensate. The resulting condensate C has a softening point of 90.
The hydroxyl group equivalent was 230 g / eq, and the melt viscosity at 150 ° C. was 0.4 Pa · s.

Example 4 Phenol-naphthol novolac condensate (condensate D)
Synthesis of Example 1 Condensate D710g was obtained by performing the same operations and reactions except that phenol 564g was changed to orthocresol 432g (4 mol). Obtained condensate D
Has a softening point of 70 ° C and a hydroxyl equivalent of 220 g / eq, 15
The melt viscosity at 0 ° C. was 0.3 Pa · s.

Comparative Example 1 Synthesis of Phenolic Novolac Condensate (Condensate E) The same operation and reaction as in Example 1 were carried out except that 1-naphthol was not used, to obtain 700 g of Condensate E.
The resulting condensate E has a softening point of 74 ° C. and a hydroxyl equivalent of 175.
g / eq, melt viscosity at 150 ° C is 0.2 Pa · s
Met.

Examples 5-12, Comparative Examples 2-5 Condensates A, B obtained in Examples 1-4 and Comparative Example 1,
Tables 1 and 2 show the results of measuring the properties of various formulations and cured products of Examples 5 to 12 and Comparative Examples 2 to 5 in which C, D and E were used as the curing agent for the epoxy resin.

[0046]

[Table 1]

[0047]

[Table 2]

The phenol novolak resin in Tables 1 and 2 is H-1 (softening point 86 ° C., hydroxyl group equivalent 104 g / eq) manufactured by Meiwa Kasei Co., Ltd., and the epoxidized orthocresol novolak resin used as the epoxy resin is Nippon Kayaku Co., Ltd. EOCN-1020 (softening point 70 ° C., epoxy equivalent 200 g / eq), and silica as a filler uses RD-8 manufactured by Tatsumori Chemical Co., Ltd., and as a curing accelerator. Triphenylphosphine was used.

The components shown in Table 1 were blended, heated to 150 ° C., melted and mixed, degassed in vacuum and then cast into a mold (thickness: 4 mm) at 150 ° C., and cured at 150 ° C. for 3 hours. After that, the resin was post-cured at 180 ° C. for 5 hours. The test methods for various physical properties are as follows. Water absorption 24 hours boiling method; Specimen size 4 × 25 × 70 mm Bending strength 3 point bending test method; Specimen size 4 × 6 × 70 mm Bending elastic modulus Same as above Breaking energy Same as above Tg TMA method (Thermal Mechanical Analysis, thermomechanical analysis Law)

For the adhesion test, the adhesives shown in Table 2 were blended, heated to 150 ° C., melted and mixed, and degreased in advance (aluminum foil 0.1 × 20 × 10).
(0 mm) is applied to 10 mm at one end, the adherends are overlaid, and the thickness of the adhesive is adjusted to 0.1 mm,
After fixing with a clamp and curing at 150 ° C for 3 hours,
It was cured at 180 ° C. for 5 hours. After curing, the T-type peel strength was measured.

From Tables 1 and 2, the phenol of the present invention
It can be seen that the naphthol novolac condensate, when used as a curing agent for epoxy resins, has extremely excellent properties such as water absorption, mechanical properties, heat resistance, and adhesive properties as compared with conventional products.

[Reference Example] Bis (meth) used in the present invention
Synthetic Example of Cimethyl) biphenyl [Reference Example 1] Iodination of methoxymethylbenzene 146.5 g (1.20 mol) of methoxymethylbenzene, 300 m of acetic acid
l, 101.5 g (0.40 mol) of iodine in a solution of 80 ml of n-hexane,
Add 70.3 g (0.40 mol) of iodic acid and 4 ml of sulfuric acid, and at 80 ℃
Stir for 5 hours. 600 ml of n-hexane and 700 ml of water in the reaction solution
After adding and shaking well, the n-hexane layer is separated, washed,
Dried. After distilling off the solvent, it was distilled under reduced pressure to remove methoxymethyl
216.5 g (0.8%) of a mixture of three isomers of luiodobenzene
7 mol) was obtained. Boiling point: 93-96 ℃ / 4mmHg. Gas Chromatography (Column: Apiezon Grease
L 10% on Uniport 2m) has 2 peaks (peak area
The ratio was 1: 3). But,¹³As a result of C-NMR measurement, o-
It was found that in addition to the body and p-body, m-body was also mixed. This
Based on these results ¹Determination of isomers in the composition from 1 H-NMR
Therefore, it is known that o-body: m-body: p-body = 1: 0.25: 2.8.
won.

Reference Example 2 Deiodine Coupling of Methoxymethyliodobenzene (3) Methoxymethyliodobenzene obtained in Reference Example 1 (3
174.3 g (0.70 mol) of isomer mixture of species, 14.2 g (46.7 mmo) of bipyridyl nickel dichloride (Ni (bipy) Cl ₂ · H ₂ O).
l), zinc powder 50.4g (0.77g atom), pyridine 9.2g (0.11
A mixture consisting of 7 mol) and 350 ml of DMI was vigorously stirred at 90 ° C. for 5.5 hours. After completion of the reaction, the solid substance was removed by suction filtration, and most of the solvent was removed by distillation under reduced pressure. After cooling, leave the residue
A 5% aqueous hydrochloric acid solution was added and mixed well to separate the layers. The oil layer was further washed with water, and a small amount of the remaining solvent was distilled off under reduced pressure.
The residue was subjected to gas chromatography analysis (SE-30, 5%, 2 m, 120 to 230 ° C) to obtain 80.3 g (0.332 mol) of a mixture of 6 isomers of bis (methoxymethyl) biphenyl. The ratio of each isomer is 2,2 '-: 2,3'-: 2,4 '-: 3,3'-: 3,4 '-: 4,4'- = 1: 0.5: 5.5:
It was 0.08: 0.3: 7.5.

[0054]

INDUSTRIAL APPLICABILITY The novel phenol-naphthol novolac condensate provided by the present invention is excellent in low hygroscopicity and heat resistance, and can be economically produced with a low melt viscosity. When used as an agent, it does not hinder the filling properties of various fillers, and can impart extremely excellent water absorption, mechanical properties, heat resistance, adhesive properties and the like to the epoxy resin cured product. In particular, it is preferably used as a curing agent for epoxy resins for the electric and electronic industries, for sealing electronic parts, and for laminated board materials.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mikito Kajima 5 1978, Kozugushi, Ube City, Yamaguchi Prefecture Ube Kosan Co., Ltd. Ube Laboratory

Claims (3)

[Claims] 1. A phenol-naphthol novolak condensate obtained by a condensation reaction of a phenol and a naphthol with a biphenyl compound. 2. A curing agent for an epoxy resin, which comprises the phenol-naphthol novolac condensate according to claim 1. 3. An epoxy resin composition containing the phenol-naphthol novolac condensate according to claim 1 and an epoxy resin, and a cured product thereof.