JP2002241475A - Polyphenol resin, its production method, and epoxy resin composition and its use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition having high flexibility and capable of forming a thin film, and its cured material has flame-retardant property. SOLUTION: This polyphenol resin having a weight average molecular weight of not less than 3,000 is obtained by condensing a phenol with a bischloromethylbiphenyl or bismethoxymethylbiphenyl, then removing unreacted phenol, and again reacting with the bischloromethylbiphenyl, and this resin is used as a curing agent for an epoxy resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyphenol resin or an epoxy resin which provides a cured product having excellent flame retardancy without containing a halogen-based flame retardant or an antimony compound, and which has flexibility enough to form a film. The present invention relates to a composition and a cured product thereof.

[0002]

2. Description of the Related Art Epoxy resins can be cured with various curing agents to give cured products having generally excellent mechanical properties, water resistance, chemical resistance, heat resistance, and electrical properties. It is used in a wide range of fields, such as laminates, molding materials, and casting materials. Conventionally, the most commonly used epoxy resin is a bisphenol A type epoxy resin. As other flame retardants, tetrabromobisphenol A and epoxidized products thereof, and compounds obtained by reacting tetrabromobisphenol A with a bisphenol A type epoxy resin are generally known.
Acid anhydrides and amine compounds are known as curing agents for epoxy resins, but phenol novolak is often used in the field of electrical and electronic components from the viewpoint of reliability.

[0003]

However, the compounds containing bromine as described above are excellent in flame retardancy, but may generate substances that cause environmental pollution during disposal or incineration. Has been pointed out. Antimony compounds used as flame retardant auxiliaries are also concerned about their toxicity. In response to this situation, demand for halogen-free and antimony-free epoxy resin compositions has been increasing in recent years as environmental protection awareness has increased.
Although a cured product of an epoxy resin by phenol novolak is excellent in reliability, the cured product is rigid and lacks flexibility. In recent years, the form of electric and electronic components is different from conventional large packages and substrates based on glass fiber. Unlike varnishes on polyimide, PET (polyethylene glycol terephthalate) films and metal foils, the solvent is Sheet-like moldings to be removed have been developed. In such a case, the resin used is required to have sufficient flexibility.

[0004]

In view of these circumstances, the present inventors have sought to provide an epoxy resin composition which gives a cured product having excellent flame retardancy and which does not impair flexibility even when molded into a sheet. As a result of intensive research, the present invention has been completed.

That is, the present invention provides (1) the following formula (1)

[0006]

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(Wherein n is an average degree of polymerization determined by an average molecular weight), and a polyphenol resin having a weight average molecular weight of 3,000 or more by GPC (gel permeation chromatography; the same applies hereinafter); Equation (1 ')

[0008]

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(Wherein n ′ represents an average degree of polymerization determined by an average molecular weight), and the formula (2) is calculated based on 1 equivalent of a phenolic hydroxyl group of a polyphenol compound having a weight average molecular weight of 1500 or less by GPC. )

[0010]

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(Wherein X is a halogen atom, having 1 to 3 carbon atoms)
Represents either an alkoxy group or a hydroxyl group. Wherein the biphenyl compound represented by the formula (1) is subjected to a condensation reaction in an amount of 0.01 mol or more and less than 0.5 mol.
A method for producing a polyphenol resin having a weight-average molecular weight of 3,000 or more by C, (3) (a) an epoxy resin having at least two epoxy groups in one molecule, and (b) containing the polyphenol resin described in (1) above. Epoxy resin composition, (4) epoxy resin having the following formula (a)

[0012]

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The epoxy resin composition according to the above (3), wherein m is an average degree of polymerization and is a positive number,
(5) The epoxy resin composition according to the above (3) or (4), containing a curing accelerator, (6) a varnish containing the polyphenol resin according to the above (1) and a solvent, (7)
A varnish comprising the epoxy resin composition according to any one of the above items (3) to (5) containing a solvent, and (8) a varnish according to the above item (6) or (7) on a plane support surface. (9) The sheet according to the above (8), wherein the planar support is a polyimide film,
0) The sheet according to the above (8), wherein the planar support is a metal foil, (11) the sheet according to the above (8), wherein the planar support is a release film, (12) the above (3) to (3). 5) A cured product obtained by curing the epoxy resin composition according to any one of the above items (13) a curing agent for an epoxy resin, comprising the polyphenol resin according to the above item (1). To provide.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
In the following, “parts” and “%” mean “parts by mass” and “% by mass”, respectively, unless otherwise specified. In the present invention, examples of the halogen atom include chlorine, bromine, and iodine, and examples of the alkoxy group having 1 to 3 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, and an i-propoxy group. It is assumed that the substituent XCH ₂ — on each phenyl group in the formula (2) is substituted at an arbitrary position selected from positions 2, 3, 4 or 2 ′, 3 ′, 4 ′. The same applies to the crosslinking group (—CH ₂ —) corresponding to this substituent in the formula (1).

The polyphenol resin of the present invention having the structure represented by the above formula (1) and having a weight average molecular weight by GPC of 3,000 or more is, for example, a polyphenol compound represented by the above formula (1 '), The biphenyl compound represented by the above formula (2) is usually used in an amount of 0.01 mol or more per 1 equivalent of the phenolic hydroxyl group.
It can be obtained by a condensation reaction in an amount of less than 5 mol, preferably 0.01 to 0.45 mol, more preferably 0.05 to 0.4 mol, in the absence of a solvent or in the presence of a solvent. I can do it.

In the condensation reaction of the present invention, an acid catalyst is appropriately used as needed. For example, when a biphenyl compound of the formula (2) in which X is a halogen atom is used, a catalyst is not particularly required, but when an alkoxy group or a hydroxyl group is used, an acid catalyst is used. In some cases, the polyphenol resin of the present invention is obtained by synthesizing a polyphenol compound represented by the formula (1 ′) by the method described below (first-stage condensation reaction) and isolating the polyphenol compound of the formula (2) without isolating the polyphenol compound. ) With a biphenyl compound (second stage condensation reaction).

The biphenyl compound of the formula (2) includes, for example, 2,2'-, 3,3'- or 4,4'-bismethoxymethylbiphenyl, 2,2'-, 3,3'- or 4'-bisemethoxymethylbiphenyl, 2,2 '
-, 3,3'- or 4,4'-bispropoxymethylbiphenyl, 2,2'-, 3,3'- or 4,4'-
Bischloromethylbiphenyl, 2,2'-, 3,3'-
Or 4,4′-bisbromomethylbiphenyl, 2,
Compounds such as 2'-, 3,3'- or 4,4'-bishydroxymethylbiphenyl are exemplified. Preferred compounds of formula (2) include those wherein X is a halogen atom, preferably a chlorine atom, or an alkoxy group, preferably a methoxy group. As the compound of the formula (2), a mixture of 2,2'-form, 3,3'-form, 4,4'-form and the like is generally available, and among them, a compound mainly containing 4,4'-form is preferable.

Preferred biphenyl compounds of the formula (2) used in the condensation reaction of the present invention include those wherein X is a halogen atom, preferably a chlorine atom.
When the condensation reaction of the present invention is carried out, the amount of the biphenyl compound represented by the formula (2) is usually 0.01 or more and less than 0.5 mol per 1 equivalent of the phenolic hydroxyl group of the compound of the formula (1 ′). , Preferably 0.01 to 0.45 mol, more preferably 0.05 to 0.4 mol. The condensation reaction of the present invention can be carried out without a solvent or in the presence of a solvent, but it is preferable to use a solvent because the viscosity increases as the molecular weight of the product increases. The solvent is not particularly limited as long as it does not adversely affect the reaction, but preferred examples include lower alkylene glycol mono- or di-lower alkyl ethers. The preferred number of carbon atoms in lower alkylene and lower alkyl is 1 to 5. Preferred solvents include, for example, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol dimethyl ether, methyl cellosolve, ethyl cellosolve and the like. The amount of the solvent used is usually 5 to 50 based on the mass of the product.
0%, preferably 10 to 400%.

In the condensation reaction of the present invention, the above-mentioned formula (2)
When a compound in which X is an alkoxy group, preferably a methoxy group, is used as the biphenyl compound represented by
It is preferable to use an acid catalyst such as hydrochloric acid, sulfuric acid, and paratoluenesulfonic acid. Of these acid catalysts, paratoluenesulfonic acid is most preferred. The reaction is performed according to the above formula (2)
Until the biphenyl compound represented by the formula is completely disappeared. The reaction temperature is usually 60 to 140 ° C, and the reaction time is usually 1
~ 20 hours.

The polyphenol compound represented by the above formula (1 ') contains phenol in an amount of usually 1.5 to 10 mol, preferably 2 to 8 mol, per mol of the biphenyl compound represented by the above formula (2). After the condensation reaction at a ratio
It can be obtained by removing unreacted phenol. In the synthesis of the polyphenol compound of the formula (1 ′) (the first-stage condensation reaction), an acid catalyst is used as necessary. For example, when a biphenyl compound of the formula (2) in which X is a halogen atom is used, a catalyst is not particularly required, but when an alkoxy group or a hydroxyl group is used, an acid catalyst is used. Preferred biphenyl compounds of the formula (2) used in this reaction include those wherein X is an alkoxy group, preferably a methoxy group. Examples of the acid catalyst in the first-stage condensation reaction include hydrochloric acid, sulfuric acid, paratoluenesulfonic acid and the like, with paratoluenesulfonic acid being particularly preferred. The amount of the acid catalyst to be used is generally 0.001 to 0.1 part, preferably 0.005 to 0.05 part, per 1 mol of the compound represented by the formula (2). The first-stage condensation reaction can be performed in the absence of a solvent or in the presence of a solvent. When a solvent is used, there is no particular problem as long as the solvent does not adversely affect the reaction, but preferred are lower alcohols such as methanol, ethanol and isopropanol, and lower alkyl lower alkyls such as methyl ethyl ketone and methyl isobutyl ketone. Ketones. The amount of the solvent to be used is generally 10 to 300%, preferably 20 to 250%, based on the total mass of the compound represented by the formula (2) and phenol. The reaction is performed until the compound represented by the formula (2) completely disappears. The reaction temperature is usually from 40 to 150 ° C, and the reaction time is usually from 1 to 10 hours. After the completion of the condensation reaction, the acid catalyst is removed by neutralization, washing with water, and the like, and then the solvent and unreacted phenol are removed under reduced pressure while heating. The condensate thus obtained has the formula (1 ′)
And has a structure in which a biphenyl molecule and a phenol molecule are bonded via a methylene bond, and the weight average molecular weight is usually about 500 to 1500. The softening point varies depending on the average molecular weight and cannot be unconditionally determined, but is usually 50 to
It is about 100 ° C.

When a compound of the formula (2) wherein X is a halogen atom is used in both the condensation reaction of the present invention and the first-stage condensation reaction, hydrogen halide produced as a by-product is removed out of the system. Is preferred. The method is not particularly limited as long as it can remove hydrogen halide out of the system. For example, during the condensation reaction, nitrogen is blown from one side of the reactor, and hydrochloric acid gas generated as a by-product is taken out from the other side by a tube or the like. The extracted hydrochloric acid can be removed by bubbling and trapping in an alkaline aqueous solution such as an aqueous sodium hydroxide solution.

The condensation reaction of the present invention is preferably carried out in a solvent, but the hydrochloric acid that cannot be completely removed by the above operation may be dissolved in the solvent at a concentration of about several thousand ppm. When the solvent solution of the polyphenol resin obtained as described below is used as it is for the varnish of the present invention, such residual hydrochloric acid is not preferable, and thus is removed as follows. That is, after the completion of the reaction, the solution is cooled to 100 ° C. or lower, water is added and stirred, hydrochloric acid is transferred to the water side under a suspension condition, and then heated and azeotropically dehydrated to simultaneously remove water containing hydrochloric acid and the solvent. And the solvent is returned to the system. By repeating this operation, most of the hydrochloric acid dissolved in the solvent can be removed. When X is a hydroxyl group or an alkoxy group, the condensation reaction of the present invention also requires an acid catalyst. In this case, the type and amount of the catalyst may be the same as in the first-stage reaction. Water or alcohol is generated as a result of the reaction, and these are removed to the outside of the system using a fractionating tube. After the completion of the reaction, by-products and, if necessary, the solvent used are removed to obtain a solid polyphenol resin.
Further, since the polyphenol resin of the present invention has a high molecular weight, depending on the purpose of use, the solvent may not be removed or the solvent may be removed until the viscosity thereof reaches an appropriate level, so that suitable workability can be ensured.

In the polyphenol resin of the formula (1) thus obtained, n represents an average value of the degree of polymerization, and is usually 4 or more, preferably 4 to 20, more preferably 4.5 to 15.
It is. The average value of the degree of polymerization is a value calculated from the number average molecular weight measured by GPC. The weight average molecular weight (GPC) is 3000 or more, but 300
0 to 20,000 is preferred. The softening point is usually 1
10 to 150 ° C., obtained in the preferred embodiment is 1
It is about 15 to 145 ° C. The hydroxyl equivalent is 2
10 to 300 g / eq, preferably 215 to 290 g / eq
eq is preferred.

The polyphenol resin composition of the present invention thus obtained is suitably used as a curing agent for an epoxy resin, a film-forming component in a varnish, and the like.

The epoxy resin composition of the present invention is characterized by containing the polyphenol resin of the present invention and an epoxy resin having two or more epoxy groups in one molecule. And uniformly mixing them. The epoxy resin is not particularly limited as long as it has two or more epoxy groups in one molecule. Specifically, novolak type epoxy resin or triphenylmethane type epoxy resin, dicyclopentadiene phenol condensed type epoxy resin, phenol novolak type epoxy resin containing xylylene skeleton, novolak type epoxy resin containing biphenyl skeleton, bisphenol A type epoxy resin, bisphenol F Type epoxy resin, tetramethylbiphenol type epoxy resin, and the like, but are not limited thereto. These epoxy resins can be used alone or in combination of two or more. Among these epoxy resins, the following formula (a)

[0026]

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(Where m represents an average value, usually 1.0 to
5, preferably a positive number from 1.1 to 4. Use of the resin represented by the formula (1) is preferable because a cured product having excellent heat resistance can be obtained. As the curing agent in the epoxy resin composition of the present invention, other curing agents may be used in addition to the polyphenol resin of the present invention. Any other curing agent can be used as long as it is used as a curing agent for an epoxy resin. For example, diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, dicyandiamide,
Polyamide resin synthesized from a dimer of linolenic acid and ethylenediamine, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, Hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, phenol novolak,
Triphenylmethane and modified products thereof, imidazo-
BF ₃ -amine complex, guanidine derivative and the like, but are not limited thereto. When these are used in combination, the proportion of the polyphenol resin of the present invention in the total curing agent is usually 0.2 equivalent or more, preferably 0.3 equivalent or more.

The amount of the curing agent used in the epoxy resin composition of the present invention is preferably 0.7 to 1.2 equivalents per equivalent of the epoxy group of the epoxy resin. When the epoxy resin composition of the present invention is used, a curing accelerator may be used in combination with the curing agent. Specific examples of the curing accelerator include imidazoles such as 2-methylimidazole, 2-ethylimidazole and 2-ethyl-4-methylimidazole, 2- (dimethylaminomethyl) phenol,
1,8-diaza-bicyclo (5,4,0) undecene-
Tertiary amines such as 7, phosphines such as triphenylphosphine, and metal compounds such as tin octylate. The curing accelerator is used in an amount of 0.1 to 5.0 parts as needed with respect to 100 parts of the epoxy resin, and may be blended as one component of the epoxy resin composition of the present invention. You may mix at the time of use.

The epoxy resin composition of the present invention may contain an inorganic filler if necessary. Specific examples of the inorganic filler include silica, alumina, and talc. The inorganic filler is used in the epoxy resin composition of the present invention in an amount of from 0 to 90.
% Are used. Furthermore, the epoxy resin composition of the present invention may contain various compounding agents such as silane coupling agents, release agents such as stearic acid, palmitic acid, zinc stearate, and calcium stearate, and pigments as necessary. Good.

The epoxy resin composition of the present invention can be obtained by uniformly mixing the above-mentioned components at a predetermined ratio, and can be used in various fields like the conventionally used epoxy resin compositions. it can. Since the polyphenol resin of the present invention having a skeleton in which a biphenyl group is bonded to phenol via a methylene group shows a high refractive index, the epoxy resin composition of the present invention containing the polyphenol resin also shows a high refractive index, It can be suitably used for optical materials such as lenses, spectacle lenses, substrates for optical disks, and plastic optical fibers. In this case, it is preferable to employ a novolak-type epoxy resin having a biphenyl skeleton having the same skeleton as the polyphenol resin of the present invention (for example, NC-3000S, NC-3000SH) manufactured by Nippon Kayaku. .

The epoxy resin composition of the present invention may optionally contain a solvent. The epoxy resin composition containing a solvent is impregnated into a base material such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, paper, etc., and is heated and dried to form a prepreg according to the present invention. Cured product of the above epoxy resin composition. The solvent content of the epoxy resin composition is usually from 10 to 70%, preferably from about 15 to 70%, based on the total amount of the epoxy resin composition of the present invention and the solvent. The epoxy resin composition containing the solvent can also be used as the following varnish. As the solvent, solvents mentioned in the section of varnish described below, for example, toluene, xylene, acetone,
Methyl ethyl ketone, methyl isobutyl ketone and the like can be mentioned.

Other components of the varnish of the present invention are not particularly limited as long as they contain the polyphenol resin of the present invention and a solvent. The varnish of the present invention only needs to be a liquid composition in which both the polyphenol resin and the solvent and optional components added as required are uniformly mixed, and the method for obtaining the liquid composition is not particularly limited. For example, as described above, obtained when producing the polyphenol resin of the present invention, using the solvent and the reaction solution containing the polyphenol resin as it is, if necessary, other optional components, from the polyphenol resin and the solvent One or two or more selected from the group may be added, or the reaction solution may be concentrated, and if necessary, other optional components and / or the polyphenol resin may be added to form the varnish of the present invention. . The varnish of the present invention may be obtained by uniformly mixing the isolated polyphenol resin with a solvent, if necessary, together with optional components.

The optional component added to the varnish of the present invention is not particularly limited as long as it does not inhibit the film formation or adhesiveness of the polyphenol resin of the present invention, but preferably forms a film together with the polyphenol resin. Macromolecules,
Epoxy compounds, additives accompanying them, and the like. The polymers are preferably soluble in the solvent used in the varnish of the present invention. One of the preferred varnishes is a varnish containing an epoxy compound. Particularly, a varnish containing the epoxy resin composition of the present invention and the polyphenol resin of the present invention is preferable. Examples of the solvent used in the varnish of the present invention include γ-butyrolactones, N-methylpyrrolidone (NMP), N, N-dimethylformamide (DMF), N, N-dimethylacetamide, N, N-dimethylimidazolidinone Amide solvents, such as sulfones such as tetramethylene sulfone,
Ether solvents such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether monoacetate, and propylene glycol monobutyl ether;
Ketone solvents such as lower alkylene glycol mono- or di-lower alkyl ethers, methyl ethyl ketone and methyl isobutyl ketone, preferably aromatic solvents such as di-lower alkyl ketones in which two alkyl groups may be the same or different, toluene and xylene Is mentioned. Preferred solvents include lower alkylene glycol mono- or di-lower alkyl ethers and the above-mentioned di-lower alkyl ketones. These may be used alone or as a mixture of two or more solvents.

The solid content concentration of the obtained varnish is usually 10
~ 90%, preferably 20-80%, more preferably 2%
5 to 70%. The balance is solvent. The content of the polyphenol resin of the present invention in a preferred varnish is 10 to 60%, preferably 20 to 50% based on the total amount of the varnish, and the content of the epoxy resin is 10 to 40%, preferably 15 to 35%. The agent is 0-20%.

The sheet of the present invention is applied to a substrate, preferably a plane support, by various coating methods such as gravure coating, screen printing, metal masking, and spin coating, which are known per se, and then dried. To be obtained. The thickness (thickness after drying) of the sheet thus obtained is, for example, 5 to 300 μm, preferably 5 to 2 μm.
It is preferably about 00 μm, more preferably about 10 to 160 μm. When applied to the surface of a planar support, it may be single-sided, double-sided or partial, if desired. Which coating method is used is appropriately selected depending on the type, shape, size, and film thickness of the coating film. As the substrate, for example, various polymers such as polyamide, polyamide imide, polyarylate, polyethylene terephthalate, polybutylene terephthalate, polyether ether ketone, polyether imide, polyether ketone, polyketone, polyethylene, polypropylene, and / or copolymers thereof Examples of the film include a film made of united material and a metal foil such as a copper foil. A film or a metal foil made of polyimide is preferable. The thus obtained sheet having a film formed from the varnish of the present invention is useful as a substrate for electric / electronic parts.

Further, the varnish of the present invention is applied on a release film, the solvent is removed under heating, and the B-stage is formed, whereby a sheet-like adhesive can be obtained. This sheet adhesive can be used as an interlayer insulating layer in a multilayer substrate or the like.

[0037]

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. The GPC measurement conditions are as follows. Model: Shodex SYSTEM-21 Column: KF-804L + KF-803L (× 2) connected Eluent: THF (tetrahydrofuran); 1 ml / m
in. , 40 ° C Detector: RI (RI-71S) UV (254 nm; UV-41) Sample: Approximately 0.4% THF solution (100 μl injection) Calibration curve: Use standard Shodex polystyrene

Example 1 A flask equipped with a thermometer, a cooling tube, a fractionating tube, and a stirrer was purged with nitrogen gas and subjected to the following formula (3).

[0039]

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121 parts of the compound represented by the formula (bismethoxymethylbiphenyl) and 188 parts of phenol were charged and heated to 130 ° C. with stirring to dissolve. Next, 0.5 parts of paratoluenesulfonic acid was added, and then the reaction was carried out for 3 hours while removing generated methanol outside the system using a fractionating tube. After completion of the reaction, methyl isobutyl ketone 260
After washing with water for three times, methyl isobutyl ketone and unreacted phenol were removed from the oil layer under reduced pressure by heating using an evaporator, whereby the compound represented by the formula (1 ′) (n ′ = 2) was removed. .2 average value) (170 parts). The softening point of the obtained compound A is 6
The melt viscosity at 8 ° C. and 150 ° C. is 0.08 Pa · s,
The hydroxyl equivalent was 204 g / eq. The weight average molecular weight measured by GPC was 940.
While performing a nitrogen gas purge on a flask equipped with a silicon tube so that the hydrochloric acid gas generated in the container at the end of the thermometer, the fractionating tube, the stirrer, and the cooling tube can be expelled out of the system,
204 parts of the obtained compound (A) has the following formula (4)

[0041]

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50.1 parts of the compound represented by the formula (bischloromethylbiphenyl) and 24.0 parts of propylene glycol monobutyl ether were charged. The tip of the silicon tube was attached so as to be immersed in another container containing an aqueous solution of sodium hydroxide. Next, the temperature was raised to 150 ° C. with stirring to carry out a dehydrochlorination reaction. The generated hydrochloric acid gas was trapped in the aqueous sodium hydroxide solution. The reaction was continued for 6 hours, and then the system was cooled to 140 ° C., and 72.0 parts of propylene glycol monobutyl ether was further added. 80 ° C
And 80 parts of warm water (120 parts) was added and suspended.
Stirred for 0 minutes. Then, water and propylene glycol monobutyl ether were distilled out of the system by heating and azeotropic dehydration,
Only propylene glycol monobutyl ether was returned to the system using a fractionating tube. The operation of adding only warm water to the operation of returning only propylene glycol monobutyl ether to the system using a fractionating tube was repeated three times, then cooled to 70 ° C., 144 parts of methyl ethyl ketone was added, and the 50% varnish of the polyphenol resin of the present invention was added. 480 parts were obtained. When the weight average molecular weight of the obtained polyphenol resin was measured using GPC, it was 12,800, and the hydroxyl equivalent was 248 g / eq. Further, n in the formula (1) was 7.0 (average value).

Example 2 An epoxy resin represented by the following formula (5)

[0044]

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A compound NC-3000P (produced by Nippon Kayaku Co., Ltd., epoxy equivalent 270 g / eq, softening point 58 ° C., n = 2.5 (average value)) represented by the following formula: 50% by weight of the polyphenol resin obtained in
73.8 propylene glycol monomethyl ether / methyl ethyl ketone solution (propylene glycol monomethyl ether: methyl ethyl ketone = 96: 144)
Parts, triphenylphosphine 0.27 as curing accelerator
And stirred at 100 ° C. for 3 hours to form a solution. The solution was cooled to room temperature to obtain a varnish of the present invention. The varnish thus obtained was applied to polyimide using an applicator so that the thickness after drying was 25 μm. The test piece was heated at 150 ° C. for 3 hours to obtain a cured product. The cured product on polyimide obtained did not crack even when the polyimide was rolled, and had a sufficient film-forming ability. This cured product was subjected to a flame retardancy test according to UL94-VTM, and it was confirmed that the cured product cleared VTM-0.

Example 3 An epoxy resin represented by the formula (a) (EPPN-50)
2H, Nippon Kayaku Co., Ltd., epoxy equivalent 170g / e
q, softening point 70.2 ° C, m in formula (1) = 1.9)
And a 50% solution of the polyphenol resin obtained in Example 1 as a curing agent, and triphenylphosphine as a curing accelerator at a mass ratio shown in Table 1 were uniformly dissolved to form a varnish. The solution was cooled to room temperature to obtain a varnish of the present invention.

Table 1 Composition of the formulation Example 1 EPPN-502H 100 50% solution of polyphenol resin 291 Triphenylphosphine 1

The varnish thus obtained was applied to a polyimide film using an applicator so that the thickness after drying was 25 μm, to obtain a test piece. Next, the test piece was heated at 180 ° C. for 3 hours to obtain a cured product. The cured product on the obtained polyimide film did not crack even when the polyimide film was rolled, and had a sufficient film-forming ability. In addition, this cured product is UL94-
When a flame retardancy test was performed according to VTM, it was confirmed that all of them cleared VTM-0. Further, the varnish thus obtained was applied to a 30-μm-thick copper foil using an applicator so that the thickness after drying became 150 μm to obtain a test piece. Next, after heating this test piece at 180 ° C. for 3 hours, the copper foil was dissolved in the etching solution to obtain a cured product. The obtained cured product is DMA (dynamic viscoelasticity measuring device)
The glass transition temperature was 208 ° C. when measured using

[0049]

When the polyphenol compound of the present invention is used as a curing agent for an epoxy resin, the polyphenol compound has flexibility and is formed into a thin film as compared with a conventionally used epoxy resin composition. Is possible,
Moreover, a cured product excellent in flame retardancy can be provided, and the epoxy resin composition of the present invention is extremely useful for a wide range of applications such as molding materials, casting materials, laminate materials, paints, adhesives, and resists. .

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F071 AA42 AA69 AA81 AC11 AE02 AF47 AH12 AH13 BA02 BB02 BC01 BC02 4J032 CA03 CA04 CA14 CA16 CB04 CC01 CD07 CE03 CG07 CG08 4J036 AF06 AF16 AF19 DA04 DA05 DA09 DB15 DC02 DC06 DC06 DC06 FB08 FB13 GA06 GA19 JA05 JA08 JA11

Claims (13)

[Claims] (1) The following formula (1): Wherein n is the average degree of polymerization determined by the average molecular weight, and the weight average molecular weight by GPC (gel permeation chromatography; hereinafter the same) is 30.
A polyphenol resin having a molecular weight of 00 or more. 2. The following formula (1 ′): Wherein n ′ represents an average degree of polymerization determined by the average molecular weight.
With respect to 1 equivalent of a phenolic hydroxyl group of a polyphenol compound having a molecular weight of 00 or less, the formula (2) (Wherein, X represents a halogen atom, an alkoxy group having 1 to 3 carbon atoms or a hydroxyl group) in a condensation reaction in an amount of 0.01 mol or more and less than 0.5 mol. A method for producing a polyphenol resin having a weight average molecular weight of 3000 or more by GPC. 3. An epoxy resin composition containing the polyphenol resin according to claim 1, wherein (a) an epoxy resin having at least two epoxy groups in one molecule. 4. An epoxy resin having the following formula (a): The epoxy resin composition according to claim 3, wherein m represents an average degree of polymerization and represents a positive number. 5. The epoxy resin composition according to claim 3, further comprising a curing accelerator. 6. A varnish containing the polyphenol resin according to claim 1 and a solvent, 7. The method according to claim 3, further comprising a solvent.
A varnish comprising the epoxy resin composition described in the above item. 8. A sheet having a layer obtained by drying the varnish according to claim 6 or 7 on a plane support surface. 9. The sheet according to claim 8, wherein the planar support is a polyimide film. 10. The sheet according to claim 8, wherein the planar support is a metal foil. 11. The sheet according to claim 8, wherein the planar support is a release film. A cured product obtained by curing the epoxy resin composition according to any one of claims 3 to 5. 13. A curing agent for an epoxy resin, comprising the polyphenol resin according to claim 1.