JPH07165852A - Allylnaphthol/alpha-naphthol cocondensate and epoxy resin composition - Google Patents

Abstract

PURPOSE:To obtain a cocondensate which has a low melting point and a low melt viscosity, is useful as a curing agent for epoxy resins, and can give a cured product excellent in heat resistance, moisture resistance, adhesion and flexibility by selecting a specified allylnaphthol$alpha/naphthol cocondensate. CONSTITUTION:This cocondensate is represented by the formula (wherein A is a residue of a naphthol represented by formula II; B is residue of alpha-naphthol represented by formula III; D is a residue of a naphthol represented by formula IV or a residue of an allylnaphthol; R<1> to R<4> are each alkyl, OH or allyl; R<5> is an aldehyde residue; l, m and n are each 0-10; at least either of Ds contains allyl when l=0 and m=0, and either of Ds is a residue of alpha-naphthol when l=0 and n=0), and has a weight-average molecular weight of 300-2000.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel allylnaphthol / α-naphthol cocondensate and an epoxy resin composition containing the cocondensate.

[0002]

2. Description of the Related Art Conventionally, in the field of electric / electronic parts, particularly semiconductor encapsulating materials, a method of encapsulating a semiconductor element with an epoxy resin composition has been widely used in order to protect it from the external environment. Has been adopted. This composition
It is composed of epoxy resin, curing agent, curing accelerator, filler and other additives. As an epoxy resin,
A resin obtained by epoxidizing a novolac resin obtained by the reaction of phenols and formaldehyde, in particular, a cresol novolac type epoxy resin is widely used, and a phenol-formaldehyde novolac resin is used as a curing agent.

However, the recent trend toward higher density and higher integration in semiconductor devices requires the encapsulant to be further improved in various properties such as heat resistance, moisture resistance and adhesion.

Particularly, in the case of mounting the semiconductor element by the surface mounting method, the package of the semiconductor element is 200
It is placed in an oven at a high temperature of about 260 ° C. and exposed to severe temperature conditions. Therefore, even if the above-mentioned epoxy resin composition is used, there is still a problem that cracks occur in the package of the semiconductor device, and the demand for high heat resistance, low water absorption and high adhesion to the cured product is becoming stronger. .

Novolak resins obtained by reacting naphthol and aldehyde have been proposed as those satisfying these requirements. This resin is intended to improve physical properties such as heat resistance and moisture resistance of a cured product by introducing a naphthol skeleton. In fact, these properties give excellent properties, but on the other hand, it has a high viscosity. Therefore, there are problems such as poor molding workability and poor adhesion.

The object of the present invention is that it is useful as a curing agent for epoxy resins and has excellent workability due to its low melting point and melt viscosity, and also has a high glass transition temperature, heat resistance, moisture resistance, adhesion and flexibility. A novel allylnaphthol / α-naphthol cocondensate capable of providing a cured product having properties and free from cracks is provided.

Another object of the present invention is a novel epoxy resin composition having a high glass transition temperature, excellent heat resistance, moisture resistance, adhesiveness and flexibility, and capable of preventing cracks from being generated in a package. Is provided.

[0008]

The allylnaphthol / α-naphthol cocondensate of the present invention is a compound represented by the following general formula (I) and having a weight average molecular weight of 300 to 2000.

[0009]

[Chemical 3]

The allylnaphthol / α-naphthol cocondensate of the present invention is a compound represented by the following general formula (II) and having a weight average molecular weight of 300 to 2000.

[0011]

[Chemical 4]

The allylnaphthol / α-naphthol cocondensate of the present invention has an allyl group introduced into the naphthol cocondensate, and therefore has a low melt viscosity and excellent workability. Furthermore, compared to naphthol co-condensates that do not have an allyl group,
Since the low melt viscosity is maintained even if the number of naphthalene nuclei in the molecule (hereinafter referred to as the number of nuclei), that is, the number of naphthols is large, the number of OH groups in the molecule can be increased. Therefore, when used as a curing agent for an epoxy resin, the crosslinking density can be increased during curing, the cured product exhibits a high glass transition temperature, and is excellent in heat resistance, moisture resistance, adhesion and flexibility.

The allylnaphthol / α-naphthol cocondensate of the present invention is a compound having a weight average molecular weight of 300 to 2000 obtained by cocondensing allylnaphthols, α-naphthols and aldehydes.

The aldehydes are preferably aliphatic aldehydes selected from formaldehyde and paraformaldehyde, or aromatic aldehydes selected from benzaldehyde, hydroxybenzaldehyde, salicylaldehyde and terephthalaldehyde.

The allylnaphthols have 1 to 2 allyl groups in the naphthalene nucleus, but preferably one in order to accelerate the condensation reaction.

The weight average molecular weight of the allylnaphthol / α-naphthol cocondensate of the present invention is 300 to 2000. If it is less than 300, the number of OH groups in the molecule is too small, and curing with epoxy becomes insufficient. If it exceeds 2000,
The melting point and viscosity of the resin are high, resulting in poor workability.

Further, the allylnaphthol.α-of the present invention
In the naphthol cocondensate, the molar ratio of the allylnaphthol molecular unit to the α-naphthol molecular unit in one molecule is preferably 10:90 to 67:33. That is, in a co-condensate having a molecular structure of co-condensation of allylnaphthols, α-naphthols and aldehydes, 1
It is preferable that the molecule contains 10 to 67 mol% of allylnaphthol molecular units and 33 to 90 mol% of α-naphthol molecular units (excluding aldehyde molecular units). If the amount is out of this range, it is difficult to obtain a cocondensate, and a large amount of a homocondensate of allylnaphthols or α-naphthol is obtained, which is not preferable.

The epoxy resin composition of the present invention contains the above allylnaphthol / α-naphthol cocondensate and an epoxy resin.

The epoxy resin composition of the present invention containing the above allylnaphthol / α-naphthol cocondensate as a curing agent preferably contains a curing accelerator, and in that case, it is particularly effective as a semiconductor encapsulating composition. is there.

In the present specification, "epoxy resin"
Unless otherwise specified, the term means not only a resinous epoxy compound but also a low molecular weight epoxy compound.

The allylnaphthol / α-naphthol cocondensate of the present invention may be any compound having a molecular structure in which allylnaphthols, α-naphthols and aldehydes are cocondensed, and it is produced, for example, by the following two methods. be able to.

(Method A) Allylnaphthols are preliminarily allylated to synthesize allylnaphthols, and α-naphthol and aldehydes are added thereto, and if necessary, an acid or a base is added to carry out dehydration reaction in the same manner as in the synthesis of ordinary novolaks. Method.

(Method B) After synthesizing a condensate with naphthols, α-naphthol and aldehydes in advance, allyl halide is reacted with a base and optionally water or an organic solvent to introduce an allyl group into the condensate. how to.

In the case of Method A, the naphthols to be allylated can be those having one or more allyl groups introduced into the molecule and one or more positions to which aldehydes can be added, such as α-naphthol and Examples thereof include dihydroxynaphthalene and α-naphthol and dihydroxynaphthalene partially substituted with an alkyl group, and α-naphthol is particularly preferable.

To allylate naphthols, (1)
A method in which naphthols and a base are added to water to form a phenolate, and then an allyl halide is added to react with it, impurities are washed with water, and then Claisen rearrangement is carried out by heating, (2) In the method of (1) above, halogenation is performed. A method of adding allyl dropwise over a long period of time, (3) a method of adding naphthols and allyl halide and, if necessary, an organic solvent and adding an aqueous base solution to the reaction to wash the impurities, and then performing Claisen rearrangement. Any method may be used.

Even if some unreacted naphthols remain, there is no problem because they are taken into the molecule of the condensate in the next cocondensation reaction.

Examples of aldehydes include formaldehyde, paraformaldehyde, acetaldehyde,
Aliphatic aldehydes such as propylaldehyde, butyraldehyde and glyoxal, aromatic aldehydes such as benzaldehyde, p-hydroxybenzaldehyde, salicylaldehyde and terephthalaldehyde can be used,
Of these, paraformaldehyde, aromatic benzaldehyde, p-hydroxybenzaldehyde, salicylaldehyde, and terephthalaldehyde are preferable. One of these aldehydes may be used for the reaction, or two or more of them may be used in combination for the reaction. Further, the amount of aldehyde used is 0.30 to 0.85 mol per 1 mol of the total amount of the allylnaphthols and α-naphthol as the raw materials so that the composition of the high-nuclide does not become too large. preferable. When the amount of the aldehyde used is less than 0.30 mol, the molecular weight of the cocondensate becomes small, so that the heat resistance of the cured product of the epoxy resin composition decreases. Also,
If it exceeds 0.85 mol, the content of the high-nuclear substance increases, the melting point becomes high, the melt viscosity becomes high, the workability deteriorates, and the moldability becomes a problem. Particularly, 0.50 to 0.75 mol is preferable.

Allylnaphthols and α in the condensation reaction
-The molar ratio used with naphthol is from 10:90 to 67: 3.
A range of 3 is preferred. If the molar ratio of allylnaphthols used is smaller than this, the effect of lowering the viscosity and flexibility is not imparted, and if the molar ratio is large, the cocondensation reaction does not proceed smoothly.

The cocondensation reaction for obtaining the allylnaphthol / α-naphthol cocondensation product of the present invention is carried out only by heating to a high temperature in order to easily control the number of naphthalene nuclei. In this case, the reaction temperature is 60 to 1
80 ° C. is suitable, and 80 to 160 ° C. is particularly preferable.
The reaction is usually completed in about 1 to 10 hours. If necessary, a catalyst such as acid or base may be used.

Although the reaction can be carried out without solvent, it is preferable to use a solvent having a boiling point of 80 ° C. or higher and a low solubility in water, such as toluene, xylene or methyl isobutyl ketone.

After completion of the reaction, impurities may be removed by washing with water or the solvent and unreacted materials may be removed under reduced pressure, if necessary.

In the case of Method B, naphthols, α-naphthol and the above-mentioned aldehydes are used to synthesize a condensate in advance by the above-mentioned condensation method or the like, and then the above-mentioned allylation methods (1), (2 ), (3) and the like to obtain the cocondensate of the present invention having a desired molecular structure.

When the allylnaphthol / α-naphthol cocondensate of the present invention is used as a curing agent for an epoxy resin, it may be used alone, but 2 or more, preferably 3 or more phenolic hydroxyl groups in the molecule. It can also be used in combination with another curing agent composed of a compound having As other curing agents, for example, phenol or a substituted phenol (o-cresol, p-cresol, t-butylphenol, cumylphenol, phenylphenol, etc.) and an aldehyde compound are reacted in the presence of an acid catalyst or a basic catalyst. Examples thereof include a usual phenol resin made to react; a reaction product of resorcin and an aldehyde compound; polyvinylphenol and the like.
The proportion of other curing agents is 70% by weight or less, preferably 50% by weight or less, based on the total curing agents.

The type of epoxy resin is not particularly limited, and conventionally known ones can be used. Examples thereof include bisphenol type, phenol novolac type, and cresol novolac type epoxy resins. Among these resins, those having a melting point exceeding room temperature and exhibiting a solid state or a highly viscous solution state at room temperature bring about good results.

The bisphenol type epoxy resin usually has an epoxy equivalent of 160 to 200 and a melting point of 50 to 1.
The one having an epoxy equivalent of 180 to 300 and the melting point of 50 to 130 ° C. is used as the phenol novolac type epoxy resin, and the epoxy equivalent of the cresol novolac type epoxy resin is 180 to 21.
Those having a melting point of 0 and a melting point of 60 to 110 ° C. are generally used.

The ratio of the epoxy resin to the curing agent is such that the equivalent ratio of the phenolic hydroxyl group of the curing agent to the epoxy group of the epoxy resin (epoxy group / phenolic hydroxyl group) is usually 1 / 0.8 to 1.2, preferably The range of 1 / 0.9 to 1.1 is preferable. When the epoxy resin and the curing agent are used in such a ratio, a cured product having excellent heat resistance and moisture resistance can be obtained.

As the curing accelerator, a usual curing catalyst can be used, and the type thereof is not particularly limited. Specific examples of the curing accelerator include, for example, triphenylphosphine, tris-2,6-dimethoxyphenylphosphine, tri-p.
-Phosphorus compounds such as tolylphosphine and triphenyl phosphite; imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole; 2 -Tertiary amines such as dimethylaminomethylphenol, benzyldimethylamine, α-methylbenzylmethylamine; 1,5-diazabicyclo [4.3.0] -5-nonene, 1,4-diazabicyclo [2.2. 2] Octane, organic bases of 1,8-diazabicyclo [5.4.0] -7-undecene, and the like.

The addition amount of the curing accelerator is preferably 0.1 to 3.0% by weight in the epoxy resin composition from the viewpoint of heat resistance and moisture resistance.

The epoxy resin composition of the present invention may contain additives as required. Examples of the additive include a filler, a surface treatment agent for treating the surface of the filler, a flame retardant, a release agent, a colorant, and a flexibility-imparting agent.

The kind of the filler is not particularly limited, and examples thereof include crystalline silica powder, fusible silica powder, quartz glass powder,
Talc, calcium silicate powder, zirconium silicate powder,
Examples thereof include alumina powder and calcium carbonate powder. Among these fillers, silica-based fillers are preferable. The proportion of filler is 60 to 90% by weight of the total composition, preferably 7%.
It is 0 to 85% by weight. If the compounding amount of the filler exceeds 90% by weight, the fluidity of the composition is lowered and molding becomes difficult, and if it is less than 60% by weight, thermal expansion tends to increase.

Examples of the surface treatment agent include known silane coupling agents, and examples of the flame retardant include antimony trioxide, antimony pentoxide, phosphates and bromides. Examples of the release agent include various waxes,
Carbon black etc. are mentioned as a coloring agent.
The flexibility-imparting agent includes, for example, silicone resin and butadiene-acrylonitrile rubber.

The method for preparing the epoxy resin composition of the present invention is not particularly limited and can be carried out according to a conventional method. In addition, conditions for encapsulating a semiconductor using the resin composition of the present invention can be appropriately selected and are not particularly limited. Explaining specifically an example of the sealing condition, for example, 175
Molding for 3 minutes at 100 ℃ / molding pressure 100kg / cm ² and
For example, after-curing at 80 ° C. for 5 hours. Usually, it is formed by transfer molding.

[0043]

EXAMPLES The embodiments of the present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

The analysis / identification of the compound is performed by gel permeation chromatography (GPC method), infrared absorption spectrum (IR) and nuclear magnetic resonance spectrum (NM).
R). The measurement conditions of GPC and NMR are shown below.

(GPC analysis) Solvent: Tetrahydrofuran Flow rate: 0.8 ml / min Column: G4000H and G3000 manufactured by Tosoh Corporation
H and G2000H (series) with exclusion limit molecular weights of 400,000, 60,000 and 10,000, respectively.
Is. Carrier: Styrene / divinylbenzene copolymer (NMR) The NMR spectrum of the synthesized product was confirmed as being assigned to the following.

[Chemical 5]

Example 1 A reaction vessel equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet was charged with 144 g (1 mol) of α-naphthol, 440 g of a 10% aqueous sodium hydroxide solution and 144 g of methyl isobutyl ketone. The mixture was heated to 60 ° C. with stirring to homogenize it to form a phenolate. To this reaction solution, 84.2 g (1.1 mol) of allyl chloride was added dropwise using a dropping funnel over 3 hours, and after completion of the addition, the mixture was stirred for 1 hour to react. After the reaction was completed, the reaction mixture was separated and washed with water, and the solvent was completely distilled off under reduced pressure. Then, the obtained reaction product was transferred to a reaction vessel, heated to 140 ° C. and stirred for 2 hours to cause a reaction to obtain allylnaphthol (OH group equivalent: 185).

37 g of the above-mentioned allylnaphthol was placed in a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet.
(0.2 mol), 115 g (0.8 mol) of α-naphthol and 22 g (0.73 mol of formaldehyde) of paraformaldehyde (allyl naphthol and α-
Total naphthol: paraformaldehyde = 1: 0.7
3 (molar ratio)) was charged, the mixture was heated to 140 ° C. and stirred under a nitrogen stream for 3 hours to cause a reaction. Next, the mixture was heated to 200 ° C. and unreacted substances and water were removed under reduced pressure to obtain an allylnaphthol / α-naphthol cocondensate represented by the following formula. This compound has a melting point of 78 ° C. and a melt viscosity of 150 ° C. of 1.6.
Poise (hereinafter referred to as P) was low and the work performance was excellent. (In the following Examples and Comparative Examples, viscosity measurements were all made at 150 ° C.) The weight average molecular weight (measured by GPC method, the same applies hereinafter) was 840, and
The H group equivalent was 172. The infrared absorption spectrum of this compound is shown in FIG.

[0048]

[Chemical 6]

Example 2 Allylnaphthol 9 as same as the one synthesized in Example 1
2.5 g (0.5 mol), α-naphthol 72 g (0.
5 mol), 86 g of xylene and 16.5 g of paraformaldehyde (0.55 mol, converted to formaldehyde)
A cocondensate was produced in the same manner as in Example 1 except that (total of allylnaphthol and α-naphthol: paraformaldehyde = 1: 0.55 (molar ratio)) was charged. Xylene was removed under heating and reduced pressure after the reaction. The obtained allylnaphthol / α-naphthol cocondensate (shown by the following formula) had a melting point of 72 ° C. and a low viscosity of 0.5 P and was excellent in workability. The weight average molecular weight was 350 and the OH group equivalent was 182.

[0050]

[Chemical 7]

Example 3 Allylnaphthol 1 the same as that synthesized in the previous stage of Example 1
11 g (0.6 mol), α-naphthol 57.6 g
(0.4 mol), toluene 184 g and paraformaldehyde 24 g (0.83 mol, converted to formaldehyde) (total of allylnaphthol and α-naphthol: paraformaldehyde = 1: 0.83 (molar ratio)) A cocondensate was produced in the same manner as in Example 1. Toluene was removed under heating and reduced pressure after the reaction. The obtained allylnaphthol / α-naphthol cocondensate (shown by the following formula) had a melting point of 71 ° C. and a low viscosity of 1.2 P, and was excellent in work performance. The weight average molecular weight was 710 and the OH group equivalent was 185.

[0052]

[Chemical 8]

Example 4 Benzaldehyde 77 instead of paraformaldehyde
A cocondensate was produced in the same manner as in Example 1 except that g was used. The obtained allylnaphthol / α-naphthol cocondensate (shown by the following formula) had a melting point of 92 ° C. and a low viscosity of 2.2 P, and was excellent in work performance. The weight average molecular weight was 1210 and the OH group equivalent was 220.

[0054]

[Chemical 9]

Example 5 A cocondensate was produced in the same manner as in Example 2 except that 89 g of p-hydroxybenzaldehyde was used instead of paraformaldehyde. Obtained allyl naphthol α
The melting point of the naphthol cocondensate (shown by the formula below) is 9
It had a low workability at 6 ° C and a viscosity of 1.2P.
The weight average molecular weight was 450 and the OH group equivalent was 135.

[0056]

[Chemical 10]

Example 6 Instead of paraformaldehyde, formalin water (37
%) A cocondensate was produced in the same manner as in Example 1 except that 60 g was used. The melting point of the obtained allylnaphthol / α-naphthol cocondensate (shown by the following formula) is 82 ° C.,
The viscosity was as low as 2.3 P and the work performance was excellent. The weight average molecular weight was 900 and the OH group equivalent was 174.

[0058]

[Chemical 11]

Example 7 Salicylaldehyde 8 instead of paraformaldehyde
A cocondensate was produced in the same manner as in Example 1 except that 9 g was used. The allylnaphthol / α-naphthol cocondensate (shown by the following formula) thus obtained had a melting point of 95 ° C. and a low viscosity of 1.9 P, and was excellent in workability. The weight average molecular weight was 700 and the OH group equivalent was 118.

[0060]

[Chemical 12]

Example 8 A cocondensate was produced in the same manner as in Example 1 except that 49 g of terephthalaldehyde was used instead of paraformaldehyde. The obtained allylnaphthol / α-naphthol cocondensate (shown by the following formula) had a melting point of 93 ° C. and a low viscosity of 3.2 P, and was excellent in work performance. The weight average molecular weight was 800 and the OH group equivalent was 179.

[0062]

[Chemical 13]

Comparative Example 1 A condensate was produced in the same manner as in Example 1 except that 144 g of α-naphthol was used instead of the allylnaphthol synthesized in the previous stage of Example 1. The obtained condensate had a high melting point of 86 ° C. and a high viscosity of 18.3 P, poor fluidity, and poor workability. Weight average molecular weight is 1280
The OH group equivalent was 165.

Comparative Example 2 Instead of paraformaldehyde, formalin water (37
%) And 0.5 g of paratoluene sulfonic acid were used to produce a condensate in the same manner as in Comparative Example 1. The obtained condensate has a high melting point of 131 ° C. and a viscosity of 76P.
Poor fluidity and poor workability. The weight average molecular weight was 1320 and the OH group equivalent was 178.

Examples 9 to 16 and Comparative Example 3 The epoxy resin, curing agent, curing accelerator, filler, antimony trioxide, silane coupling agent, wax and carbon black shown below are shown in Tables 1 and 2. The epoxy resin composition for semiconductor encapsulation was prepared by mixing in a ratio (parts by weight), kneading with a two-roll mill at a temperature of 70 to 110 ° C., then cooling and pulverizing.

Epoxy resin: o-cresol novolac type epoxy resin (epoxy equivalent 195, melting point 85 ° C.) brominated phenol novolac type epoxy resin (epoxy equivalent 280, melting point 83 ° C.) Curing agent: obtained in Examples 1 to 8 Co-condensate Phenol novolac resin (hydroxyl group equivalent 106, melting point 80 ° C) Curing accelerator: Triphenylphosphine filler: Spherical silica (BF1 of Mitsubishi Metals Co., Ltd.)
00)

The composition obtained was treated at 175 ° C. and 100 kg.
/ Cm ² , molded under curing conditions of 3 minutes, then 180
A post-cure was performed under the conditions of ° C and 6 hours to prepare a molded test piece. This test piece is an 80-pin four-way flat package (80-pin QFP, size 20 x 14 x 2 mm)
And the die pad size is 8 × 8 mm.

The semiconductor device thus obtained was subjected to a TCT test of −50 ° C./5 minutes to 150 ° C./5 minutes to check the number of cracks. In addition, the test piece,
A crack resistance test was performed by allowing the sample to stand in a constant temperature bath having a relative humidity of 85 ° C./85% RH to absorb moisture, and then immersing it in a solder melt at 260 ° C. for 10 seconds. The results are shown in Tables 3 and 4.

The bending strength (high temperature strength) at 200 ° C. of the obtained test piece, the glass transition temperature, the coefficient of thermal expansion,
The water absorption was examined after a humidification test at 85 ° C./85% RH for 500 hours. The results are shown in Tables 5 and 6.

[0070]

[Table 1]

[0071]

[Table 2]

[0072]

[Table 3]

[0073]

[Table 4]

[0074]

[Table 5]

[0075]

[Table 6]

[0076]

The allylnaphthol / α-naphthol cocondensate of the present invention has a low melting point and melt viscosity and is excellent in workability. When it is used as a curing agent for epoxy resin, the obtained epoxy resin cured product has a high glass transition temperature, heat resistance and moisture resistance, and cracks are less likely to occur in the package even during soldering.

A cured product of the epoxy resin composition of the present invention containing this allylnaphthol / α-naphthol cocondensate as a curing agent has a high glass transition temperature, excellent heat resistance, high mechanical strength, and water absorption. Is small and has excellent moisture resistance, and cracks are extremely few even during soldering. Therefore, the epoxy resin composition of the present invention is useful as a semiconductor encapsulating composition.

[Brief description of drawings]

FIG. 1 is an infrared absorption spectrum diagram of an allylnaphthol / α-naphthol cocondensate produced in Example 1.

Claims (5)

[Claims] 1. An allylnaphthol / α-naphthol cocondensate represented by the following general formula (I) and having a weight average molecular weight of 300 to 2,000. [Chemical 1] 2. An allylnaphthol / α-naphthol cocondensate represented by the following general formula (II) and having a weight average molecular weight of 300 to 2,000. [Chemical 2] 3. An allylnaphthol / α-naphthol cocondensate having a weight average molecular weight of 300 to 2000 obtained by cocondensing allylnaphthols, α-naphthols and aldehydes. 4. The molar ratio of the allylnaphthol molecular unit to the α-naphthol molecular unit in one molecule is 10:90 to 6.
The allylnaphthol / α-naphthol cocondensate according to any one of claims 1 to 3, which is 7:33. 5. An epoxy resin composition comprising the allylnaphthol / α-naphthol cocondensate according to any one of claims 1 to 4 and an epoxy resin.