JP7658256B2 - Ester-modified phenolic compounds - Google Patents

Description

The present invention relates to an ester-modified phenol compound that reacts with an epoxy compound or a curing agent to give a cured product having excellent electrical properties, heat resistance, etc.

Cured products obtained by reacting ester-modified phenolic compounds with epoxy resins and curing agents have excellent electrical properties and heat resistance, and are therefore used in circuit boards, semiconductor encapsulants, machine parts, adhesives, and the like.
For example, Patent Document 1 describes a cured product of an ester-modified phenolic compound obtained by esterifying a phenolic compound having a dicyclopentadiene skeleton, and describes its use as an insulating material for multilayer printed circuit boards.

JP 2009-235165 A

In recent years, due to the increasing heat generation during use caused by the high density of semiconductors and the need to reduce the power consumption of high frequency circuit board materials, heat resistance, low dielectric constant, low dielectric loss tangent, etc. are required for electronic device components.
However, the cured product of the ester-modified phenol compound described in Patent Document 1 does not have sufficient electrical properties.
An object of the present invention is to provide an ester-modified phenol compound which gives a cured product having excellent electrical properties, heat resistance, crack resistance, moisture resistance, moldability, etc.

The gist of the present invention resides in an ester-modified phenol compound obtained by esterifying all or a part of the phenolic hydroxyl groups of a phenol compound represented by the following formula (1):

In formula 1, each R is independently a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms.
is an integer from 0 to 4, b is an integer from 0 to 3, and n is an integer from 0 to 20.

The ester-modified phenol compound of the present invention has excellent electrical properties, heat resistance, crack resistance,
The cured product has excellent moisture resistance, moldability, etc. The cured product is useful for circuit boards, semiconductor encapsulation materials,
It can be used for machine parts, adhesives, paints, civil engineering and building materials, insulating materials for electrical and electronic parts, optical materials, etc.

The ester-modified phenol compound of the present invention is a phenol compound represented by the following formula 1:
It has a structure in which all or a part of the phenolic hydroxyl groups are esterified.

The ester-modified phenol compound of the present invention has a structure derived from tricyclopentadiene (TCPD), and thus the heat resistance of the cured product is improved.
Furthermore, since the hydroxyl group concentration is lower and the polarity is lower than that of conventional phenolic compounds, the cured product has a low dielectric constant and a low dielectric loss tangent.
In the above formula 1, each R is independently a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms.

Examples of the hydrocarbon group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a cyclohexyl group, etc. From the viewpoints of fluidity and curability, R is preferably a methyl group or an ethyl group, and more preferably a methyl group.
The bonding position (substitution position) of R to the hydroxyl group of the benzene ring is preferably the ortho-position or para-position, more preferably the para-position, from the viewpoint of ease of production.

"a" is an integer of 0 to 4. In view of fluidity, "a" is preferably an integer of 0 to 2, more preferably an integer of 0 or 1, and particularly preferably 0.
b is an integer of 0 to 3. In terms of fluidity, b is preferably an integer of 0 to 2, more preferably 0 or 1, and particularly preferably 0.
n is an integer of 0 to 20. From the viewpoints of fluidity and curing properties, n is preferably an integer of 0 to 10, and more preferably 0.
Up to 5 is more preferred, and 0 to 2 is particularly preferred.
Furthermore, in the present invention, the compound represented by formula 1 is preferably a phenol compound represented by formula 2 below.

n is an integer of 0 to 20, preferably 0 to 10 from the viewpoints of fluidity and curing property, and more preferably 0 to 5
is more preferred, and 0 to 2 is particularly preferred.
Examples of the compound that undergoes an esterification reaction with all or a part of the phenolic hydroxyl groups include monocarboxylic acids or acid halides thereof, and dicarboxylic acid compounds or acid halides thereof.

As the monocarboxylic acid or its acid halide, aromatic monocarboxylic acid or its acid halide is preferable from the viewpoint of excellent heat resistance and electrical properties when cured, and examples thereof include benzenecarboxylic acid, naphthalenecarboxylic acid, compounds having one or more substituents such as an aliphatic hydrocarbon group, an alkoxy group, a halogen atom, an aryl group, an aralkyl group, etc. on the aromatic nucleus, and acid halides thereof.

The dicarboxylic acid compound or its acid halide has a high heat resistance when cured,
From the viewpoint of excellent electrical properties, aromatic dicarboxylic acids or acid halides thereof are preferable, and examples thereof include aromatic dicarboxylic acids such as isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, and 2,6-naphthalenedicarboxylic acid, and acid halides thereof such as acid fluorides, acid chlorides, acid bromides, and acid iodides.

Among these, acid halides of aromatic dicarboxylic acids are preferred because of their particularly good reactivity, and dichloride of isophthalic acid and dichloride of terephthalic acid are more preferred, with dichloride of isophthalic acid being particularly preferred.
In addition, from the viewpoint of the electrical properties of the cured product when used as a curing agent, the ester-modified phenol compound of the present invention preferably has a terminal structure derived from the monohydroxy compound, in which a monocarboxylic acid or an acid halide thereof, or a dicarboxylic acid compound or an acid halide thereof is used in combination with a monohydroxy compound during esterification.

As the monohydroxy compound, aromatic monohydroxy compounds are preferred from the viewpoint of excellent heat resistance and electrical properties when cured, and examples thereof include phenol, o-cresol, m-cresol, p-cresol, 2,4-xylenol, 3,5-xylenol, o-phenylphenol, p-phenylphenol, 2-benzylphenol, 4-benzylphenol, 4-(1-methyl-1-phenylethyl)phenol, 1-naphthol, 2-naphthol, etc. Among these, 1-naphthol and 2-naphthol are preferred from the viewpoint of low dielectric tangent of the cured product.

The phenol compound preferably has a number average molecular weight (Mn) of 400 to 1,000, as calculated using standard polystyrene, as measured by gel permeation chromatography (GPC).
The phenol compound preferably has a weight average molecular weight (Mw) of 450 to 1,500, as calculated using standard polystyrene, as determined by gel permeation chromatography (GPC).
The number average molecular weight and the weight average molecular weight are preferably high from the viewpoint of curability of the resin composition.
From the viewpoint of suppressing gelation of the resin composition, a lower value is preferable.
Furthermore, the hydroxyl equivalent of the phenol compound, as measured, for example, by an alkali back titration method of an acetylated product in a pyridine-acetic anhydride solution, is preferably 190 or more and 300 or less. A higher hydroxyl equivalent is preferable from the viewpoint of curability of the resin composition, and a lower hydroxyl equivalent is preferable from the viewpoint of suppressing gelation of the resin composition.

An example of a method for producing the phenol compound represented by the formula 1 will be described below.
The phenol compound of the present invention can be produced by reacting a phenol having a phenolic hydroxyl group with tricyclopentadiene in the presence of an acid catalyst.
Tricyclopentadiene used as a raw material component of the phenolic resin of the present invention is, for example,
It can be synthesized from dicyclopentadiene by a known method, such as the method described in Appl. Organometal. Chem. 2014, 28, pp. 151-155.

The phenols are not particularly limited, but examples thereof include phenol, cresol, xylenol, ethylphenol, propylphenol, isopropylphenol, n-butylphenol, sec-butylphenol, tert-butylphenol, pentylphenol, hexylphenol, and cyclohexylphenol. Phenol, cresol, and xylenol are particularly preferred from the standpoint of economy and ease of production.
More than one species may be used in combination.

The molar ratio of tricyclopentadiene to the phenols used in the reaction can be appropriately adjusted to adjust the molecular weight and melt viscosity of the target phenol compound within an appropriate range.
The molar ratio of phenols to tricyclopentadiene is preferably in the range of 2 to 64, and more preferably 4.
A molar ratio of phenols/tricyclopentadiene is preferably in the range of up to 32. The molar ratio of phenols/tricyclopentadiene is preferably higher in terms of the melt viscosity of the phenol compound, and is preferably lower in terms of synthesis efficiency.

Examples of the acid catalyst include inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid, organic acids such as formic acid, acetic acid, oxalic acid, trifluoromethanesulfonic acid, and p-toluenesulfonic acid, and Friedel-
Examples of the craft catalyst include boron trifluoride, boron trifluoride-ether complex, boron trifluoride-phenol complex, boron trifluoride-water complex, boron trifluoride-alcohol complex, and boron trifluoride-amine complex. Mixtures of these can also be used.
Among these, boron trifluoride-phenol complex, boron trifluoride-ether complex, trifluoromethanesulfonic acid, and p-toluenesulfonic acid are preferably used from the standpoint of catalytic activity and ease of catalyst removal.

The amount of the catalyst used is not particularly limited as long as the molecular weight and melt viscosity of the resin are within appropriate ranges. For example, when phenol and tricyclopentadiene are reacted using p-toluenesulfonic acid as a catalyst, the amount of p-toluenesulfonic acid/(phenol+tricyclopentadiene) is preferably 0.1 to 5.0% by weight, and more preferably 0.5 to 3.0% by weight.

The reaction is usually preferably carried out in a closed system by replacing the atmosphere in a reactor with an inert gas such as nitrogen or argon, but may also be carried out in an open system while supplying an inert gas into the reactor.
The reaction temperature is usually 60 to 180° C., preferably 100 to 160° C., more preferably 120
In the range of 100° C. to 150° C., a higher temperature is preferable from the viewpoint of reactivity, and a lower temperature is preferable from the viewpoint of suppressing the distillation of phenols and the decomposition of tricyclopentadiene.

In the present invention, a solvent may be used when reacting a phenol with tricyclopentadiene in the presence of an acid catalyst. Considering the high temperature reaction, the solvent is, for example, toluene, o-cyclopentadiene, etc.
Xylene, p-xylene, m-xylene, ethylene glycol monobutyl ether, and the like are preferred.
The reaction is terminated by deactivating the catalyst. There are no particular limitations on the means for deactivation, but it is preferable to use a means that reduces the amount of ionic impurities such as boron and fluorine remaining in the finally obtained phenolic resin to 100 ppm or less. Examples of deactivating agents that can be used for this purpose include inorganic bases such as alkali metals, alkaline earth metals, or oxides, hydroxides, and carbonates thereof, ammonium hydroxide, hydrotalcites, and ammonia gas.

After the reaction is completed, the deactivator and other substances are removed by filtration, separation, etc., to recover a reaction liquid free of impurities. During filtration, the workability can be improved by adding a solvent, increasing the temperature of the filtrate, or applying increased or reduced pressure in the system.
The reaction mixture after removing the deactivating agent is concentrated by distillation to remove and recover the unreacted phenols. The distillation can be carried out under any of normal pressure, elevated pressure, and reduced pressure conditions.

Next, an example of a method for producing the ester-modified phenol compound of the present invention will be described.
The ester-modified phenol compound of the present invention can be produced by reacting the phenol compound with the monocarboxylic acid or its acid halide, or the dicarboxylic acid compound or its acid halide in the presence of an organic solvent and an alkali catalyst. It is also preferable to use a monohydroxy compound in combination.

The reaction ratio of the phenol compound and monohydroxy compound to the dicarboxylic acid or its acid halide is preferably 0.47 to 0.53 moles of the dicarboxylic acid or its acid halide per mole of the total of the hydroxyl groups of the phenol compound and monohydroxy compound, because this allows the target active ester compound to be obtained in high yield and suppresses the production of by-products.
A molar ratio is preferred.

The ratio of the phenol compound to the monohydroxy compound used in the reaction is preferably 1.0 to 10.0, more preferably 1.5 to 5.0, and particularly preferably 2.0 to 4.0, in terms of the equivalent ratio of hydroxyl groups. The higher the hydroxyl group equivalent ratio, the better from the viewpoints of the heat resistance and electrical properties of the cured product, and the lower the ratio, the better from the viewpoints of the solvent solubility of the ester-modified phenol compound and the inhibition of gelation.
Examples of the alkali catalyst include sodium hydroxide, potassium hydroxide, triethylamine, pyridine, and 4-dimethylaminopyridine. These may be used alone or in combination of two or more. They may also be used as an aqueous solution of about 3.0 to 30%. Among these, sodium hydroxide, potassium hydroxide, and 4-dimethylaminopyridine, which have high catalytic activity, are preferred.

In addition to the alkali catalyst, this reaction may be carried out using an acid scavenger, such as pyridine or triethylamine.
The organic solvent may be a ketone solvent such as acetone, methyl ethyl ketone, methyl isobutyl ketone, or cyclohexanone; an acetate solvent such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, or carbitol acetate; or a carbitol solvent such as cellosolve or butyl carbitol.

Examples of the solvent include aromatic hydrocarbon solvents such as toluene and xylene, chloroform, dichloromethane, dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. These may be used alone or in combination of two or more. Among these, toluene, xylene, and chloroform are preferred from the viewpoint of uniformly dissolving the phenol compound, the dicarboxylic acid or its acid chloride, and the monohydroxy compound.

The reaction temperature is preferably from 20 to 100°C, more preferably from 20 to 80°C, and particularly preferably from 20 to 60°C.
The reaction pressure is preferably normal pressure. The reaction time is preferably 0.5 to 10 hours.
More preferably, it is up to 5 hours.
After the reaction is completed, in the case where an aqueous solution of an alkaline catalyst is used, the reaction solution is allowed to stand and separated, the aqueous layer is removed, and the remaining organic layer is washed and the process of standing and separating is repeated until the aqueous layer becomes almost neutral.
Furthermore, the solvent can be removed from the organic layer by distillation concentration to obtain the desired resin.

The number average molecular weight (Mn) of the ester-modified phenol compound of the present invention is preferably 500 to 1,500, as calculated using standard polystyrene, as measured by gel permeation chromatography (GPC).
The ester-modified phenol compound of the present invention can also be analyzed by gel permeation chromatography (GPC).
The weight average molecular weight (Mw) measured by standard polystyrene conversion is 1000 to 3000.
is preferred.

The number average molecular weight and weight average molecular weight are preferably high from the viewpoints of heat resistance and electrical properties of the cured product, and are preferably low from the viewpoints of the solvent solubility of the ester-modified phenol compound and inhibition of gelation.
From the resin composition containing the ester-modified phenolic compound of the present invention and an epoxy resin, a cured product having excellent electrical properties, heat resistance, crack resistance, moisture resistance, moldability, etc. can be obtained.

Examples of the epoxy resin include epoxy resins derived from divalent phenols, such as bisphenol A type epoxy resins, bisphenol C type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol AD type epoxy resins, resorcin type epoxy resins, hydroquinone type epoxy resins, catechol type epoxy resins, dihydroxynaphthalene type epoxy resins, biphenol type epoxy resins, and tetramethylbiphenol type epoxy resins.

Phenol novolac type epoxy resins, cresol novolac type epoxy resins, trisphenolmethane type epoxy resins, tetraphenylethane type epoxy resins, dicyclopentadiene-phenol modified type epoxy resins, phenol aralkyl type epoxy resins, biphenyl aralkyl type epoxy resins, naphthol novolac type epoxy resins, naphthol aralkyl type epoxy resins, naphthol-phenol co-condensed novolac type epoxy resins, naphthol-cresol co-condensed novolac type epoxy resins.

Examples of the epoxy resin include epoxy resins derived from trivalent or higher phenols such as aromatic hydrocarbon formaldehyde resin-modified phenol resin-type epoxy resins, biphenyl-modified novolac type epoxy resins, tetrabromobisphenol A type epoxy resins, and brominated phenol novolac type epoxy resins.
The epoxy resin may contain a polymeric epoxy resin or a phenoxy resin. Examples of the polymeric epoxy resin include 1256, YX8100BH30, and YX6954.
BH30, YX6900BH45, YX7553BH30, YX7482BH30, YX
7200B35, YX7800BH40, YX7891T30 (all manufactured by Mitsubishi Chemical).

From the viewpoints of flowability and further the heat resistance of the cured product, the epoxy resin is preferably a bisphenol A type epoxy resin, a bisphenol C type epoxy resin, a tetramethylbiphenol type epoxy resin, a 4,4'-biphenol type epoxy resin, a biphenyl aralkyl type epoxy resin, a phenol aralkyl type epoxy resin, a dicyclopentadiene-phenol modified type epoxy resin, an orthocresol novolac type epoxy resin, or a trisphenolmethane type epoxy resin.

These epoxy resins may be used in combination of two or more kinds. Also, a part of the epoxy groups may be modified with an ester compound or the like.
In order to fully exhibit heat resistance after reaction with the ester-modified phenolic compound, the epoxy resin preferably has an epoxy equivalent of 400 g/equivalent or less, more preferably 350 g/equivalent or less, and even more preferably 300 g/equivalent or less. In order to fully ensure reactivity with the ester-modified phenolic compound, the epoxy resin preferably has an epoxy equivalent of 100 g/equivalent or more, more preferably 120 g/equivalent or more, and even more preferably 150 g/equivalent or more.

The weight average molecular weight (Mw) of the epoxy resin, measured by gel permeation chromatography (GPC) and converted into standard polystyrene, is preferably in the range of 500 to 10,000.
If the Mw is 500 or more, the dielectric properties and/or water absorption rate tend to be excellent. From the viewpoint of maintaining these properties better, the Mw of the epoxy resin is more preferably 600 or more, and more preferably 700 or more.
00 or more is more preferable, and 1000 or more is particularly preferable.

From the viewpoint of maintaining the resin viscosity and/or softening point appropriately and achieving good handleability, the Mw of the epoxy resin is preferably 10,000 or less, more preferably 8,000 or less, even more preferably 7,000 or less, and particularly preferably 6,000 or less.
In the resin composition of the present invention, the functional group equivalent ratio of the ester bond site of the ester-modified phenol compound per 1 equivalent of the epoxy group of the epoxy resin in the resin composition is 0.2 or more, and 5.
It is preferably 0 or less, more preferably 0.5 or more and 2.0 or less, and even more preferably 0.7 or more and 1.5 or less. If it is larger or smaller than this range, the curability of the resin composition may decrease and the heat resistance of the cured product may decrease.

The resin composition may contain additives such as a curing accelerator and an inorganic filler.
Examples of the hardening accelerator include phosphorus compounds, tertiary amines, imidazoles, organic acid metal salts, Lewis acids, amine complex salts, etc., with tertiary amines and imidazoles being preferred. These may be used in combination of two or more kinds.
Examples of inorganic fillers include fused silica, crystalline silica, glass powder, alumina, silicon nitride, talc, aluminum hydroxide, calcium carbonate, calcium sulfate, etc., and fused silica is preferred in terms of the amount of incorporation. These may be used in combination of two or more kinds.

The cured product obtained by curing the resin composition of the present invention has excellent crack resistance, heat resistance, moisture resistance, moldability, etc., and can be used for circuit boards, semiconductor encapsulants, machine parts, adhesives, paints, civil engineering and building materials, insulating materials for electric and electronic parts, optical materials, etc.

The present invention will be described below with reference to examples. The present invention was evaluated by the following methods.

<Number average molecular weight (Mn) and weight average molecular weight (Mw) of phenolic compounds and ester-modified phenolic compounds>
The measurement was carried out using a GPC "HLC-8220GPC" manufactured by Tosoh Corporation under the following measurement conditions.
As standard polystyrene, TSK Standard Polystyrene: F-
A calibration curve was prepared using F-450, F-128, F-20, F-4, F-2, A-2500, and A-1000, and the number average molecular weight and weight average molecular weight were measured in terms of polystyrene.
Column: Tosoh Corporation "TSKGEL SuperHZM-N" x 3 Eluent: Tetrahydrofuran Flow rate: 0.35 ml/min
Detection: RI
Temperature: 40°C
Sample concentration: 0.1% by weight
Injection volume: 10 μl

<Weight average molecular weight of epoxy compound>
The GPC "HLC-8320GPC" manufactured by Tosoh Corporation was used under the following measurement conditions. Standard polystyrenes were F-128, F-10, F-4, F-2, A-5000, and A-2.
A calibration curve was prepared using A-500 and A-300, and the weight average molecular weight was measured in terms of polystyrene.
Column: TSKGEL Super HM-H+H5000+H4000 manufactured by Tosoh Corporation
+H3000+H2000”
Eluent: tetrahydrofuran Flow rate: 0.5 ml/min
Detection: UV (wavelength 254 nm)
Temperature: 40°C
Sample concentration: 0.1% by weight
Injection volume: 10 μl

<Hydroxyl group equivalent>
The hydroxyl equivalent of the phenol compound was measured by a method using an acetylation reagent in accordance with the neutralization titration method of JIS K0070-1992.

<Epoxy equivalent>
The epoxy equivalent of the epoxy compound was measured in accordance with JIS K7236: 2001. In the case of a solution, the value was expressed as a solid content equivalent value.

<Glass transition temperature>
The analysis was performed using a viscoelasticity measuring device "DMS6100" manufactured by Hitachi High-Technologies Corporation. The temperature was raised from 30°C to 280°C at 5°C/min at 1 GHz, and the elastic modulus tan δ (E''/
The maximum value of E') was taken as the glass transition temperature.

<Dielectric properties>
The dielectric properties (dielectric constant: Dk, dielectric loss tangent: Df) of the test pieces of the epoxy resin cured material were measured at measurement frequencies (1 GHz and 10 GHz) by the cavity resonance perturbation method using a network analyzer. (The size of the test piece was 2 mm wide, 80 mm long, and 300 μm thick.)
)
The dielectric properties were calculated using dedicated measurement software provided by the manufacturer of the cavity resonator.
Equipment used: Network analyzer manufactured by Agilent Technologies
E8361A,
Cavity resonator: CP215 (1 GHz), CP184 (10 GHz) manufactured by Kanto Electronics Application Development Co., Ltd. Measurement environment: temperature 23°C, relative humidity 50% RH

<Ingredients used>
The raw materials used in the following examples and comparative examples are as follows.
Tricyclopentadiene (TCPD): Applied Organometallic
The catalyst was Pd(dba)2 as a transition metal catalyst and P(p-tolyl) as a ligand.
3 was used.
Phenol: manufactured by Nacalai Tesque, Inc. p-Toluenesulfonic acid monohydrate: manufactured by Fuji Film Wako Pure Chemical Industries, Ltd. Chloroform: manufactured by Kanto Chemical Co., Ltd. Isophthalic acid dichloride: manufactured by Tokyo Chemical Industry Co., Ltd. 1-Naphthol: manufactured by Tokyo Chemical Industry Co., Ltd. Triethylamine: manufactured by Tokyo Chemical Industry Co., Ltd. 4,4'-Dimethylaminopyridine: manufactured by Fuji Film Wako Pure Chemical Industries, Ltd. Toluene: manufactured by Fuji Film Wako Pure Chemical Industries, Ltd. Ethyl acetate: manufactured by Fuji Film Wako Pure Chemical Industries, Ltd. Silica gel (60N (spherical, neutral) 63-210 μm): manufactured by Kanto Chemical Co., Ltd. Hardener (product name "HPC-8000-65T"): manufactured by DIC Corporation Epoxy resin (product name "YX7891T30", Mn: 10000, Mw: 30000,
Epoxy equivalent: 6000 g/equivalent, resin content: 30% by mass): manufactured by Mitsubishi Chemical Corporation

<Production Example 1 (Phenol Compound)>
Into a four-neck flask equipped with a stirrer, a thermometer, and a dropping funnel was added 212.7 g (2.
26 mol) and 14.0 g (0.07 mol) of TCPD were added, and the inside of the flask was replaced with nitrogen gas. The inside temperature was raised to 90° C. while stirring, and the contents were heated and dissolved. Then, an aqueous solution of 4.2 g of p-toluenesulfonic acid monohydrate dissolved in 4.2 mL of water was added to the dropping funnel, and the inside temperature was raised to 90-
The mixture was slowly added dropwise while maintaining the temperature at 100°C.

The internal temperature was then raised to 140° C. and the reaction was carried out for 3 hours. After the reaction was completed, the internal temperature was lowered to 90° C., and 6.2 g of a 20% aqueous potassium hydroxide solution was added to deactivate the catalyst.
The temperature was raised to 0° C. and the unreacted phenol was distilled off under reduced pressure. Thereafter, the reaction solution was cooled to 60° C. and transferred to a separatory funnel while being diluted with chloroform.
The chloroform solution was washed with a 20% aqueous potassium hydroxide solution, and then washed with water until the pH of the aqueous layer reached 7. After removing the solvent with an evaporator, the phenol compound (TCPD
The resulting phenol compound was purified by chromatography (silica gel, eluent: ethyl acetate/toluene=1/18) to obtain 21 g of a compound. The purified phenol compound had an Mn of 467, an Mw of 486, and a hydroxyl equivalent of 20.
It was 9 g/eq.

<Production Example 2 (Ester-modified phenol compound)>
Into a four-neck flask equipped with a rotor, a thermometer, and a dropping funnel was added 7.5 g of the phenol compound (TCPD/PHL novolak) synthesized in Production Example 1 (number of moles of phenolic hydroxyl groups: 35.
9 mmol), isophthalic acid chloride 5.1 g (24.9 mmol), 1-naphthol 2
.1 g (14.4 mmol) and 0.1 g of 4,4'-dimethylaminopyridine were added, and the atmosphere was replaced with nitrogen gas.

Next, 65 g of toluene was charged under nitrogen flow and dissolved with stirring. After dissolution, 5.1 g (50.1 mmol) of triethylamine was placed in the dropping funnel, and the flask was cooled in an ice-water bath to slowly dropwise add the triethylamine while maintaining the internal temperature at 10 to 20° C. After dropping, the ice bath was removed, and the reaction was carried out for 3 hours at an internal temperature of 20 to 30° C.
After the reaction was completed, the reaction solution was transferred to a separatory funnel and washed with water until the pH of the aqueous layer reached 7. After removing the solvent with an evaporator, 13 g of an ester-modified phenolic compound (TCPD/PHL novolak type ester) was obtained. The Mn of the obtained ester-modified phenolic compound was 87.
3. Mw was 1,822, and the ester value calculated from the charged amount was 3.58 mmol/g.

<Production Example 3 (Epoxy Resin)>
As the epoxy resin, an orthocresol novolac type epoxy resin (epoxy equivalent: 1
97 g/equivalent, Mn: 416, average number of epoxy groups per molecule: 2.1) 100 parts by weight,
As an ester compound, benzoic acid-2-naphthyl (active equivalent: 248 g/equivalent) 44.5
parts by weight, 4,4'-dimethylaminopyridine, 0.0400 parts by weight, toluene, 16.1
The weight parts were placed in a reaction vessel equipped with a stirrer and reacted at 130° C. for 6 hours in a nitrogen gas atmosphere (the reaction molar ratio of epoxy groups/ester groups was 2.8).
Thereafter, the mixture was diluted with 45.9 parts by weight of toluene to obtain a modified epoxy resin solution.
The epoxy equivalent of the modified epoxy resin (solid content) is 441 g/equivalent, and the weight average molecular weight is 2040.
The resin content was 69.7%.

Example 1
4,4'-Dimethylaminopyridine was dissolved in toluene so that the content was 5 mass %. Each compound and solution was weighed and mixed so as to obtain the solid content ratio shown in Table 1, to obtain a solution of an epoxy resin composition.
The obtained epoxy resin composition solution was applied to a release PET film (a silicone-treated polyethylene terephthalate film) using an applicator having a thickness of 300 μm and a width of 5 cm.
The film was dried at 100° C. for 0.5 hour, at 160° C. for 1.5 hours, and then at 200° C. for 1.5 hours to obtain a film of a cured epoxy resin.
The obtained cured film was cut into test pieces of the size required for each evaluation, and the heat resistance and dielectric properties were evaluated according to the above-mentioned methods. The results are shown in Table 1.

<Comparative Example 1>
4,4'-Dimethylaminopyridine was dissolved in toluene to a content of 5 mass %. Each compound and solution was weighed and mixed to obtain the solid content ratio shown in Table 1, to obtain a solution of an epoxy resin composition.
The obtained epoxy resin composition solution was applied to a release PET film (a silicone-treated polyethylene terephthalate film) using an applicator having a thickness of 300 μm and a width of 5 cm.
The film was dried at 100° C. for 0.5 hour, at 160° C. for 1.5 hours, and then at 200° C. for 1.5 hours to obtain a film of a cured epoxy resin.

The heat resistance and dielectric properties were evaluated. The results are shown in Table 1.

As can be seen from Table 1, the cured product obtained using the curing agent containing a dicyclopentadiene-type diphenol structure in Comparative Example 1 has a low glass transition temperature, insufficient heat resistance, a high dielectric constant and dielectric tangent, and poor electrical properties.

Claims (9)

An ester-modified phenol compound obtained by esterifying all or a part of the phenolic hydroxyl groups of a phenol compound represented by the following formula (1):

In formula 1, each R is independently a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms.
is an integer from 0 to 4, b is an integer from 0 to 3, and n is an integer from 0 to 20. The ester-modified phenol compound according to claim 1 , wherein the formula 1 is represented by the following formula 2:

In formula 2, n is an integer from 0 to 20. The ester-modified phenol compound according to claim 1 or 2, wherein all or a part of the phenolic hydroxyl groups are esterified with a dicarboxylic acid compound or an acid halide thereof. Any one of claims 1 to 3, wherein the terminal has a structure derived from a monohydroxy compound.
Item 1. The ester-modified phenol compound according to item 1. A resin composition comprising the ester-modified phenol compound according to any one of claims 1 to 4 and an epoxy resin. The resin composition according to claim 5, wherein the epoxy resin is an epoxy resin having di- or higher-functional glycidyl groups. 6. The resin composition according to claim 5, wherein the ester-modified phenol compound is contained in an amount of 0.7 or more and 1.5 or less in terms of the equivalent of a functional group at an ester bond site relative to 1 equivalent of an epoxy group of an epoxy resin in the resin composition.
Or the resin composition according to claim 6. A cured product obtained by curing the resin composition according to any one of claims 5 to 7. An electric/electronic part comprising the cured product of claim 8.