WO2023074258A1

WO2023074258A1 - Active ester compound

Info

Publication number: WO2023074258A1
Application number: PCT/JP2022/036769
Authority: WO
Inventors: 和貴木坂; 達彦入江; 豪太瀧本
Original assignee: 東洋紡株式会社
Priority date: 2021-10-28
Filing date: 2022-09-30
Publication date: 2023-05-04
Also published as: TW202323358A

Abstract

The present invention provides: an epoxy resin composition having excellent dielectric loss tangent and heat resistance; and a cured object thereof.　This epoxy resin composition is characterized by being an active ester compound that contains an epoxy resin (A), a first active ester compound (B-1), and a second active ester compound (B-2), and is characterized in that the first active ester compound (B-1) has a dimer acid backbone and/or a dimer diol backbone in the molecule thereof.

Description

Active ester compound

The present invention relates to an active ester compound and a composition and cured product using the same.

In recent years, with the increase in the amount of communication information, information transmission in high frequency bands has become popular, and it has become important to suppress the transmission loss of insulating materials for communication. Epoxy resin is used as an insulating material with excellent electrical properties for printed wiring boards and sealants. However, in order to use it as an insulating material for high-frequency communication, it is necessary to further reduce the dielectric loss tangent in order to suppress transmission loss. It has been demanded.

Conventionally, compounds with active hydrogen, such as primary amines, secondary amines, polyfunctional carboxylic acids, and phenolic resins, have been used as curing agents for epoxy resins. In some cases, a low dielectric loss tangent could not be obtained due to the reaction between the epoxy resin and these curing agents to generate highly polar hydroxy groups at the ends of the molecular chains.

As an attempt to suppress the highly polar hydroxyl group and eliminate the deterioration of the electrical properties caused by it, for example, Patent Document 1 discloses the presence or absence of a catalyst in an epoxy resin, polyvalent carboxylic acid, phenols, naphthol esters with compounds containing hydroxy groups or mercapto groups selected from heterocyclic compounds having N, O and/or S atoms, or benzoic acid and aromatic hydroxy compounds, aromatic sulfur compounds, hydroquinone, polyhydric alcohols, phenols An epoxy resin curable composition is disclosed which comprises one or more esters with a compound containing a hydroxy group or a mercapto group selected from resins and polyvinylphenols.

JP-A-62-53327

Insulating layers formed on multilayer printed wiring boards and the like in recent years are required to have a low dielectric loss tangent. In order to reduce the dielectric loss tangent of the epoxy resin cured product, it is effective to use an active ester curing agent as the curing agent. However, the epoxy resin curable composition disclosed in Patent Document 1 does not have a sufficient dielectric loss tangent, and is difficult to use as an electric/electronic material for high frequencies.

Therefore, the present invention combines an active ester compound having a dimer acid skeleton and/or a dimer diol skeleton as a curing agent with another active ester compound to produce a cured product with an epoxy resin having excellent dielectric properties and heat resistance. intended to provide

As a result of intensive studies to solve the above problems, the present inventors have found that a compound in which a dimer acid skeleton and/or a dimer diol skeleton is incorporated in the molecule of an active ester compound and an active ester compound having an aromatic skeleton are combined. The inventors have found that the epoxy resin cured product can be imparted with excellent dielectric loss tangent and heat resistance, and have completed the present invention.

That is, the present invention includes the following configurations.
[1] Contains an epoxy resin (A), a first active ester compound (B-1) and a second active ester compound (B-2), wherein the first active ester compound (B-1) is a dimer An epoxy resin composition characterized by being an active ester compound having an acid skeleton and/or a dimer diol skeleton in its molecule.
[2] The epoxy resin composition according to [1], wherein the ratio of the first active ester compound (B-1) to the total active ester compound is 20 to 80% by mass.
[3] The second active ester compound (B-2) is a reaction product of an aromatic polyhydroxy compound, an aromatic polycarboxylic acid compound or its acid halide, and an aromatic monohydroxy compound. The epoxy resin composition according to [1] or [2], characterized by:
[4] The terminal structure of the first active ester compound (B-1) is represented by formula (1) or formula (2)

(In the formula, each R is independently an aliphatic hydrocarbon group, an alkoxy group, a halogen atom, an aryl group, or an aralkyl group, n is an integer of 0 to 5, and m is an integer of 0 to 7. .) The epoxy resin composition according to any one of [1] to [3], which is an active ester compound represented by:
[5] The epoxy resin composition according to any one of [1] to [4], wherein the first active ester compound (B-1) has a molecular weight of 500 to 5,000.
[6] The aromatic polyhydroxy compound constituting the second active ester compound (B-2) is the following (X-1) to (X-4)

(In the formula, each X is independently hydrogen or a methyl group. i is 1 or 2.) The epoxy according to any one of [3] to [5], Resin composition.
[7] A cured product of the epoxy resin composition according to any one of [1] to [6].

According to the present invention, the epoxy resin composition comprises an epoxy resin, an active ester compound (B-1) having a dimer acid skeleton and/or a dimer diol skeleton in the molecule, and another active ester compound (B-2). It is characterized by containing A cured product of the epoxy resin composition has excellent dielectric loss tangent and heat resistance.

<Epoxy resin composition>
The epoxy resin composition of the present invention contains an epoxy resin (A), a first active ester compound (B-1) and a second active ester compound (B-2), and the first active ester compound ( B-1) is characterized in that it is an active ester compound having a dimer acid skeleton and/or a dimer diol skeleton in its molecule. The first active ester compound (B-1) and the second active ester compound (B-2) act as a curing agent for the epoxy resin (A), and the cured product of the epoxy resin composition (hereinafter referred to as epoxy resin curing Also called a thing.) can be obtained. Since both dielectric properties and heat resistance of the epoxy resin cured product are improved, the ratio of the active ester compound (B-1) to the total active ester compound is preferably in the range of 20 to 80% by mass, preferably 25 to 80% by mass. It is more preferably in the range of 60% by mass.

<First active ester compound (B-1)>
The first active ester compound (B-1) of the present invention (hereinafter also simply referred to as active ester compound (B-1)) has a function as a curing agent for epoxy resins. Furthermore, by having a dimer acid skeleton and/or a dimer diol skeleton (hereinafter also collectively referred to as a dimer skeleton) in the molecule (in the structure), a cured product excellent in dielectric loss tangent can be obtained. Although the reason is not necessarily clear, it is presumed to be due to the following reasons. That is, having a dimer skeleton in the molecule significantly reduces the polarity of the active ester compound (B-1). Therefore, it is possible to lower the polarity of the cured product with the epoxy resin, and to lower the dielectric properties.

Although the dimer acid is not particularly limited, it is preferably a C20-60 aliphatic dicarboxylic acid produced by dimerization of a C10-30 unsaturated fatty acid made from vegetable oil. Although the number of carbon atoms in the dimer acid is not particularly limited, it is preferably in the range of 30-50, more preferably in the range of 36-44. Although the dimer diol is not particularly limited, it is preferably a diol produced by hydrogenating an acid group of an aliphatic carboxylic acid produced by dimerization of an unsaturated fatty acid. Although the number of carbon atoms in the dimer diol is not particularly limited, it is preferably in the range of 30-50, more preferably in the range of 36-44.

The active ester compound (B-1) may have one dimer skeleton in its molecule, or may have two or more. One is preferable. The dimer skeleton may be either a dimer acid skeleton or a dimer diol skeleton, but a dimer diol skeleton is preferred. Further, the dimer acid skeleton exists in the active ester compound (B-1) as a dimer acid residue, and the dimer diol skeleton exists as a dimer diol residue.

The ester bond possessed by the active ester compound is preferably a reaction product of a phenolic hydroxyl group and a carboxylic acid (an esterified product of a phenolic hydroxyl group and a carboxylic acid). By having such an ester bond, it has high reactivity with the epoxy group of the epoxy resin described later. This high reactivity can prevent or suppress the generation of hydroxy groups caused by ring-opening of epoxy groups. The active ester compound preferably has two or more of the ester bonds. More preferably, it is four or more. Also, the number is preferably 10 or less, more preferably 6 or less. By having the ester bond within the above range, it becomes easy to suppress the generation of hydroxy groups, and the dielectric loss tangent of the cured product with the epoxy resin is further improved.

In addition, the active ester compound of the present invention preferably has no hydroxyl group in the molecule or has a hydroxyl value of 30 eq/ton or less, more preferably 15 eq/ton or less. Therefore, the hydroxy group derived from the active ester compound does not exist or hardly exists in the cured product obtained by the reaction of the active ester compound.

Thus, according to the active ester compound of the present invention, generation of hydroxy groups during curing can be prevented or suppressed. It is generally known that a highly polar hydroxy group increases the dielectric loss tangent, but the use of the active ester compound of the present invention makes it possible to achieve a low dielectric loss tangent in a cured product.

In addition, since the active ester compound (B-1) of the present invention has a dimer acid skeleton and/or a dimer diol skeleton, the molar volume of the molecule is increased. In addition, since the dimer acid skeleton and/or the dimer diol skeleton have a low polarity structure, the polarity in the molecule becomes small. For this reason, the polarity of the cured product as a whole is also lowered, and it is presumed that a low dielectric loss tangent was achieved.

The active ester compound (B-1) is liquid at room temperature (25° C.) from the viewpoint of better balance between handleability during the curing reaction with the epoxy resin and heat resistance and dielectric properties of the cured product. Alternatively, it preferably has a softening point or melting point in the range of 40°C to 200°C.

The number average molecular weight of the active ester compound (B-1) is preferably 500 or more, more preferably 800 or more, still more preferably 1000 or more. Also, it is preferably 5,000 or less, more preferably 4,000 or less, and still more preferably 3,000 or less. By setting it within the above range, the dielectric loss tangent of the cured product with the epoxy resin can be improved.

The terminal structure of the active ester compound (B-1) is preferably of formula (1) or formula (2). The terminal structures of formulas (1) and (2) are preferably those obtained by the reaction between the phenolic hydroxyl group and the carboxylic acid. When the terminal structure has the formula (1) or formula (2), it has high reactivity with the epoxy resin and can prevent or suppress generation of hydroxy groups caused by ring-opening of the epoxy groups. In addition, the active ester compound preferably has a total of two or more terminal structures of formula (1) and formula (2), and may have three or more. Also, the number is preferably 6 or less, more preferably 4 or less. Having a plurality of terminal structures of formula (1) or formula (2) can further increase the reactivity with epoxy resins, and more effectively prevent or suppress the generation of hydroxy groups caused by ring-opening of epoxy groups. be able to. The active ester compound (B-1) may contain both the terminal structure of formula (1) and the terminal structure of formula (2) in the molecule. preferably have the same terminal structure.

Each R in Formula (1) and Formula (2) is independently an aliphatic hydrocarbon group, an alkoxy group, a halogen atom, an aryl group, or an aralkyl group.

Although the aliphatic hydrocarbon group is not particularly limited, it is preferably an aliphatic hydrocarbon group having 1 to 30 carbon atoms. Specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, tert-pentyl group, neopentyl group , 1,2-dimethylpropyl group, n-hexyl group, isohexyl group, n-nonyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group and the like. Among them, a methyl group is preferred.

Alkoxy groups include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, octyloxy, 2-ethylhexyloxy, nonyloxy, decyloxy, and undecyloxy groups.

　The halogen atom includes a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and the like.

The aryl group is not particularly limited, but is preferably an optionally substituted aryl group having 5 to 30 carbon atoms or an optionally substituted heteroaryl group having 3 to 30 carbon atoms. . Substituents include the aforementioned aliphatic hydrocarbon groups, alkoxy groups, and halogen atoms. Moreover, when having a substituent, the number of carbon atoms includes the carbon of the substituent. Specifically, one hydrogen atom is removed from monocyclic aromatic compounds such as benzene, furan, pyrrole, thiophene, imidazole, pyrazole, oxazole, isoxazole, thiazole, isothiazole, pyridine, pyrimidine, pyridazine, pyrazine, and triazine. condensed aromatic compounds such as naphthalene, anthracene, phenalene, phenanthrene, quinoline, isoquinoline, quinazoline, phthalazine, pteridine, coumarin, indole, benzimidazole, benzofuran, and acridine from which one hydrogen atom has been removed mentioned. A combination of a plurality of these aromatic compounds may also be used, for example, ring-assembled aromatic compounds such as biphenyl, binaphthalene, bipyridine, bithiophene, phenylpyridine, phenylthiophene, terphenyl, diphenylthiophene, and quaterphenyl. from which one hydrogen atom is removed; diphenylmethane, diphenylethane, 1,1-diphenylethane, 2,2-diphenylpropane, naphthylphenylmethane, triphenylmethane, dinaphthylmethane, dinaphthylpropane, phenylpyridylmethane, Examples thereof include aromatic compounds such as fluorene and diphenylcyclopentane, which are linked by alkylene and have one hydrogen atom removed.

Aralkyl groups include benzyl, phenethyl, phenylpropyl, naphthylmethyl and naphthylethyl groups.

Among the above, R is more preferably an aryl group, more preferably benzene, toluene, naphthalene, or anthracene from which one hydrogen atom has been removed, and benzene or naphthalene from which one hydrogen atom has been removed. is particularly preferred, and benzene from which one hydrogen atom has been removed is most preferred.

n in formula (1) and formula (2) is an integer of 0 to 5, preferably an integer of 1 to 4, more preferably an integer of 1 to 3, more preferably 1 or 2 Yes, preferably 1. Also, m is an integer of 0 to 7, preferably an integer of 1 to 4, more preferably an integer of 1 to 3, still more preferably 1 or 2, and particularly preferably 1. * indicates a bond with the active ester compound (B-1).

<Second active ester compound (B-2)>
The second active ester compound (B-2) of the present invention (hereinafter also simply referred to as active ester compound (B-2)) has a function as a curing agent for epoxy resins.

The active ester compound (B-2) is not particularly limited as long as it has an active ester group, but is an aromatic polyhydroxy compound, an aromatic polycarboxylic acid compound or its acid halide, and an aromatic monohydroxy compound. is preferably a reactant of

The aromatic polyhydroxy compound is not particularly limited, but catechol, resorcinol, benzenediol such as hydroquinone; bisphenol A, bisphenol F, bisphenol M, bisphenol P and other bisphenol compounds; bisphenol fluorene, 1,1'-bi- Compounds having two phenolic hydroxyl groups in one compound such as 2-naphthol, 4,4′-biphenol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone; Compounds having three phenolic hydroxyl groups in one compound such as 2,3,4-trihydroxybenzophenone, 2,4,6-trihydroxybenzophenone, 4,4′,4″-methylidynetrisphenol; compounds having four phenolic hydroxyl groups in one compound such as hydroxybenzophenone and tetrakis(4-hydroxyphenyl)methane; and compounds in which two or more phenols are crosslinked with an alicyclic compound. Among these, bisphenol A, bisphenol F, bisphenol M, bisphenol P, bisphenol fluorene, 1,1'-bi-2-naphthol, and compounds in which two or more phenols are crosslinked with an alicyclic compound are preferred. , more preferably bisphenol A, bisphenolfluorene, 1,1'-bi-2-naphthol, a compound in which two or more phenols are crosslinked with an alicyclic compound, more preferably bisphenol A, 1,1'- B-2-naphthol. By using the aromatic polyhydric hydroxy compound as the above compound, the dielectric properties and heat resistance of the epoxy resin cured product are further improved. The aromatic polyhydric hydroxy compounds may be used alone or in combination of two or more.

The aromatic polyhydroxy compound is preferably any one of (X-1), (X-2), (X-3) or (X-4) below. In (X-1), each X is independently hydrogen or a methyl group, preferably two X's are both methyl groups. Also, i is 1 or 2 in (X-4). The aromatic polyhydric hydroxy compound may be used alone or in combination of two or more.

The aromatic monohydroxy compound may be any compound as long as it has a substituted or unsubstituted aromatic ring group and one hydroxyl group on the aromatic ring, and other specific structures are particularly Not limited. Moreover, an aromatic monohydroxy compound may be used individually by 1 type, and may be used in combination of 2 or more types. The monohydroxy compounds are specifically phenol, 4-tert-butylphenol, 1-naphthol, 2-naphthol, o-cresol, m-cresol, p-cresol, 1-anthracenol, 2-anthracenol. , 9-anthracenol, 4-phenylphenol and the like. Furthermore, compounds having one or more substituents on these aromatic nuclei are included. Substituents on the aromatic nucleus include aliphatic hydrocarbons such as methyl group, ethyl group, vinyl group, propyl group, butyl group, pentyl group, hexyl group, cyclohexyl group, heptyl group, octyl group and nonyl group. Alkoxy groups such as methoxy, ethoxy, propyloxy, and butoxy; halogen atoms such as fluorine, chlorine, and bromine; phenyl, naphthyl, and anthryl groups; A group hydrocarbon group, an alkoxy group, an aryl group substituted with a halogen atom, etc.; Examples thereof include aralkyl groups substituted with halogen atoms and the like. Among these, phenol, 4-tert-butylphenol, 1-naphthol, 2-naphthol and 4-phenylphenol are preferred, and phenol, 1-naphthol, 2-naphthol and 4-phenylphenol are more preferred. , phenol, 1-naphthol and 2-naphthol are more preferred. Among these, phenolic compounds and naphthol compounds are preferable because they improve the curability, the dielectric properties of the cured product, and the heat resistance. Moreover, it is preferable that the aromatic monohydroxy compound forms a terminal structure of the active ester compound. The above aromatic monohydroxy compounds may be used alone or in combination of two or more.

If the aromatic polycarboxylic acid or acid halide thereof is a compound capable of forming an ester bond by reacting with the phenolic hydroxyl group of the aromatic monohydroxy compound and the aromatic polyhydroxy compound, the specific structure is not particularly limited. Specific examples include benzenedicarboxylic acids such as orthophthalic acid, isophthalic acid, and terephthalic acid; benzenetricarboxylic acids such as trimellitic acid; naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, and naphthalene-2,3. - naphthalenedicarboxylic acids such as dicarboxylic acids, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid; triazinecarboxylic acids such as 1,3,5-triazine-2,4,6-tricarboxylic acid; and These acid halides and the like are included. Furthermore, compounds in which the above-described aliphatic hydrocarbon groups, alkoxy groups, halogen atoms, etc. are substituted on these aromatic nuclei are included. Acid halides include, for example, acid chlorides, acid bromides, acid fluorides, acid iodides and the like. Among these, benzenedicarboxylic acid and benzenetricarboxylic acid are preferred, and isophthalic acid, terephthalic acid, isophthalic acid dichloride, terephthalic acid dichloride, 1,3,5-benzenetricarboxylic acid and 1,3,5-benzenetricarbonyl Trichloride is more preferred, and isophthalic acid dichloride, terephthalic acid dichloride, and 1,3,5-benzenetricarbonyltrichloride are even more preferred. Each of these may be used alone, or two or more of them may be used in combination. Benzenecarboxylic acids, such as isophthalic acid and terephthalic acid, or acid halides thereof are preferred because of their excellent curability and the dielectric properties of the resulting cured product.

The active ester compound (B-2) has a softening point or a melting point of 40° C. to 200° C. from the viewpoint of better balance between handleability during the curing reaction with the epoxy resin, heat resistance of the cured product, and dielectric properties. is preferably in the range of

The number average molecular weight of the active ester compound (B-2) is preferably 300 or more, more preferably 600 or more. Also, it is preferably 4000 or less, more preferably 3000 or less. By setting it within the above range, the dielectric loss tangent of the cured product with the epoxy resin can be improved.

<Method for producing active ester compound (B-1)>
The method for producing the active ester compound (B-1) is not particularly limited, and it can be produced by a known method as appropriate.

The method for producing the active ester compound (B-1) of the present invention preferably includes a step of reacting a dimer acid and/or dimer diol with a compound having a phenolic hydroxyl group and a polycarboxylic acid compound or an acid halide thereof. . Specifically, when a dimer acid is used, the active ester compound (B-1) can be obtained by reacting the dimer acid with a compound having a phenolic hydroxyl group. Further, when dimer diol is used, an active ester compound (B-1) can be obtained by reacting a compound obtained by reacting a polycarboxylic acid compound or an acid halide thereof with a compound having a phenolic hydroxyl group with dimer diol. .

Specific polycarboxylic acid compounds or acid halides thereof are not particularly limited, but orthophthalic acid, isophthalic acid, benzenedicarboxylic acids such as terephthalic acid; benzenetricarboxylic acids such as trimellitic acid; naphthalene-1,5-dicarboxylic acid; acid, naphthalene-2,3-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid and the like naphthalenedicarboxylic acids; 2,4,5-pyridinetricarboxylic acid and the like pyridinetricarboxylic acids;1 , 3,5-triazine-2,4,6-tricarboxylic acid; and acid halides thereof. Among these, benzenedicarboxylic acid and benzenetricarboxylic acid are preferred, and isophthalic acid, terephthalic acid, isophthalic acid dichloride, terephthalic acid dichloride, 1,3,5-benzenetricarboxylic acid and 1,3,5-benzenetricarbonyl Trichloride is more preferred, and isophthalic acid dichloride, terephthalic acid dichloride, and 1,3,5-benzenetricarbonyltrichloride are even more preferred. The above polycarboxylic acid compounds or acid halides thereof may be used alone, or two or more of them may be used in combination.

A compound having a phenolic hydroxyl group has a substituted or unsubstituted aromatic ring group. Specific compounds having a phenolic hydroxyl group are not particularly limited, but phenol, 4-tert-butylphenol, 1-naphthol, 2-naphthol, 1-anthrol, 2-anthrol, 9-anthrol, 4- Phenylphenol etc. are mentioned. Among these, phenol, 4-tert-butylphenol, 1-naphthol, 2-naphthol and 4-phenylphenol are preferred, and phenol, 1-naphthol, 2-naphthol and 4-phenylphenol are more preferred. , phenol, 1-naphthol and 2-naphthol are more preferred. It is preferable that the compound having the phenolic hydroxyl group forms the terminal structure of the active ester compound. The above-mentioned compounds having phenolic hydroxyl groups may be used alone or in combination of two or more.

The molar ratio of the polycarboxylic acid compound or its acid halide and the compound having a phenolic hydroxyl group is not particularly limited, but the polycarboxylic acid compound or its acid halide relative to the number of moles of hydroxyl groups in the compound having a phenolic hydroxyl group The molar ratio of the total number of moles of carboxy groups and acid halide groups [(total of carboxy groups and acyl halide groups)/(hydroxy groups)] is preferably 0.6 to 3.0, and 0 .8 to 2.0 is more preferred, and 1.0 to 1.2 is even more preferred.

The amount of the compound having a phenolic hydroxyl group is preferably 1 mol or more, more preferably 1.5 mol or more, and still more preferably 2 mol or more, relative to 1 mol of the dimer skeleton. Also, it is preferably 10 mol or less, more preferably 8 mol or less, and still more preferably 4 mol or less.

The reaction conditions for the active ester compound (B-1) are not particularly limited, and known techniques can be employed as appropriate.

Although the pH during the reaction is not particularly limited, it is preferably 11 or higher. At this time, a base such as sodium hydroxide, potassium hydroxide, calcium hydroxide, or ammonia can be used to adjust the pH.

The reaction temperature is also not particularly limited, preferably 20 to 100°C, more preferably 40 to 80°C. The reaction pressure is also not particularly limited, and normal pressure is more preferable. The reaction time is also not particularly limited, preferably 0.5 to 12 hours, more preferably 1 to 6 hours.

<Method for producing active ester compound (B-2)>
The method for producing the active ester compound (B-2) is not particularly limited, and it can be produced by a known method as appropriate.

The method for producing the active ester compound (B-2) of the present invention comprises a step of reacting an aromatic polyhydroxy compound, an aromatic polycarboxylic acid compound or an acid halide thereof, and an aromatic monohydroxy compound. is preferred. The steps include step 1 of reacting an aromatic polycarboxylic acid compound or an acid halide thereof with an aromatic monohydroxy compound, and the product obtained in step 1 (hereinafter also referred to as step 1 product). It is more preferable to include step 2 of reacting an aromatic polyhydric hydroxy compound.

The step 1 is a step of reacting an aromatic polycarboxylic acid compound or its acid halide with an aromatic monohydroxy compound. The molar ratio of the aromatic polycarboxylic acid compound or its acid halide and the aromatic monohydroxy compound is not particularly limited, but the aromatic polycarboxylic acid compound or The molar ratio of the total number of moles of carboxy groups and acid halide groups in the acid halide [(total of carboxy groups and acyl halide groups)/(hydroxy groups)] is 0.6 to 3.0. is preferred, 0.8 to 2.0 is more preferred, and 1.0 to 1.2 is even more preferred. In step 1, it is preferable to use an aromatic polycarboxylic acid compound or an acid halide thereof as a solvent and reagent. When the aromatic polycarboxylic acid compound or its acid halide is used as a solvent and reagent, it is preferable to remove excess (unreacted) aromatic polycarboxylic acid compound or its acid halide after the reaction. The above molar ratio of the aromatic polycarboxylic acid compound or acid halide thereof and the aromatic monohydroxy compound is based on the amount (excluding the solvent) used as the reagent.

The reaction conditions in step 1 are not particularly limited, but the reaction temperature is preferably 80 to 180°C, more preferably 100 to 150°C. The reaction pressure is also not particularly limited, and normal pressure is more preferable. The reaction time is also not particularly limited, preferably 0.5 to 12 hours, more preferably 1 to 6 hours.

The step 2 is a step of reacting the product of the step 1 with an aromatic polyhydric hydroxy compound. The molar ratio between the step 1 product and the aromatic polyhydroxy compound is preferably 1.5 mol or more, more preferably 1.8, of the step 1 product per 1 mol of the aromatic polyhydroxy compound. It is mol or more, more preferably 2 mol or more. Also, it is preferably 5 mol or less, more preferably 4 mol or less, and still more preferably 3 mol or less.

The pH during the step 2 reaction is not particularly limited, but is preferably 11 or higher. At this time, a base such as sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia, or triethylamine can be used to adjust the pH.

The reaction temperature in step 2 is also not particularly limited, preferably 20 to 100°C, more preferably 40 to 80°C. The reaction pressure is also not particularly limited, and normal pressure is more preferable. The reaction time is also not particularly limited, preferably 0.5 to 12 hours, more preferably 1 to 6 hours.

<Epoxy resin>
The epoxy resin preferably contains two or more epoxy groups in the molecule and is a curable resin that can be cured by forming a crosslinked network with the epoxy groups. The number of epoxy groups contained in the molecule is preferably 3 or more, more preferably 4 or more. Also, it is preferably 10 or less, more preferably 6 or less. By having an epoxy group within the above range, the reactivity with the active ester compound is improved and the curability is improved.

The epoxy resin is not particularly limited, but phenol novolak type epoxy resin, cresol novolak type epoxy resin, α-naphthol novolak type epoxy resin, β-naphthol novolak type epoxy resin, bisphenol A novolak type epoxy resin, biphenyl novolak type epoxy resin. Novolak type epoxy resins such as resins; aralkyl type epoxy resins such as phenol aralkyl type epoxy resin, naphthol aralkyl type epoxy resin, phenol biphenyl aralkyl type epoxy resin; bisphenol A type epoxy resin, bisphenol AP type epoxy resin, bisphenol AF type epoxy resin , bisphenol B type epoxy resin, bisphenol BP type epoxy resin, bisphenol C type epoxy resin, bisphenol E type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, tetrabromobisphenol A type epoxy resin, etc. biphenyl-type epoxy resins such as biphenyl-type epoxy resins, tetramethylbiphenyl-type epoxy resins, epoxy resins having a biphenyl skeleton and diglycidyloxybenzene skeleton; naphthalene-type epoxy resins; binaphthol-type epoxy resins; binaphthyl-type epoxy resins; dicyclopentadiene dicyclopentadiene-type epoxy resins such as phenol-type epoxy resins; glycidylamine-type epoxy resins such as tetraglycidyldiaminodiphenylmethane-type epoxy resins, triglycidyl-p-aminophenol-type epoxy resins, and diaminodiphenylsulfone glycidylamine-type epoxy resins;2 , 6-naphthalene dicarboxylic acid diglycidyl ester type epoxy resin, hexahydrophthalic anhydride glycidyl ester type epoxy resin, etc.; dibenzopyran, hexamethyldibenzopyran, 7-phenylhexamethyldibenzopyran, etc. benzopyran type epoxy resin and the like. The above epoxy resins may be used alone or in combination of two or more.

<Epoxy resin composition>
The epoxy resin composition of the present invention (hereinafter also simply referred to as composition) comprises the active ester compound (B-1), the active ester compound (B-2) and the epoxy resin. In addition, other resins, solvents, other curing agents, additives and the like may be further included as necessary. Hereinafter, the active ester compound (B-1) and the active ester compound (B-2) are collectively referred to as an active ester compound.

Although the content of the active ester compound in the composition is not particularly limited, it is preferably 1 to 90% by mass, more preferably 5 to 80% by mass, based on the solid content of the composition. When the content of the active ester compound is 1% by mass or more or 90% by mass or less, it is preferable because the cured product can have a low dielectric loss tangent. As used herein, the term "solid content of the composition" means the total mass of the components excluding the solvent in the composition.

The mass ratio of the content of the active ester compound to the content of the epoxy resin (active ester compound/epoxy resin) is preferably 1 or more, more preferably greater than 1, and preferably 1.1 or more. More preferably, it is particularly preferably 1.2 or more. It is preferable that the mass ratio is 1 or more because the cured product can have a lower dielectric loss tangent. Also, it is preferably 5 or less, more preferably 2 or less. Curability becomes favorable because the said mass ratio is 5 or less. In general, when the content of the active ester compound exceeds the content of the epoxy resin, the dielectric loss tangent becomes low as the content of the active ester compound relatively increases.

<Other curing agents>
In the composition, other curing agents may be used together with the active ester compound according to the present invention. Other curing agents include, but are not particularly limited to, other active ester compounds, amine curing agents, imidazole curing agents, acid anhydride curing agents, phenolic curing agents, and the like.

The other active ester compounds are not particularly limited, but include active ester compounds other than the active ester compounds described above.

The amine curing agent is not particularly limited, but diethylenetriamine (DTA), triethylenetetramine (TTA), tetraethylenepentamine (TEPA), dipropylenediamine (DPDA), diethylaminopropylamine (DEAPA), N-aminoethyl Aliphatic amines such as piperazine, mencenediamine (MDA), isophoronediamine (IPDA), 1,3-bisaminomethylcyclohexane (1,3-BAC), piperidine, N,N,-dimethylpiperazine, triethylenediamine; m-xylylenediamine (XDA), metaphenylenediamine (MPDA), diaminodiphenylmethane (DDM), diaminodiphenylsulfone (DDS), benzylmethylamine, 2-(dimethylaminomethyl)phenol, 2,4,6-tris(dimethyl and aromatic amines such as aminomethyl)phenol.

Examples of the imidazole curing agent include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, and epoxy-imidazole adducts.

Examples of the acid anhydride curing agent include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol bis trimellitate, glycerol tri trimellitate, maleic anhydride, tetrahydro phthalic anhydride, methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, succinic anhydride, and methylcyclohexenedicarboxylic anhydride.

Examples of the phenol-based curing agent include phenol novolak resin, cresol novolak resin, naphthol novolak resin, bisphenol novolak resin, biphenyl novolak resin, dicyclopentadiene-phenol addition type resin, phenol aralkyl resin, naphthol aralkyl resin, and triphenol methane type resin. , tetraphenol ethane type resin, aminotriazine-modified phenol resin, and the like.

The above-mentioned other curing agents may be used alone or in combination of two or more.

<Solvent>
The composition of the invention may contain a solvent. Preferably, the solvent does not react with the active ester compound, the epoxy resin, or the like, and has a function of adjusting the viscosity of the composition.

Specific examples of the solvent include, but are not limited to, ketones such as acetone, methyl ethyl ketone, and cyclohexanone; esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; Examples include carbitols, aromatic hydrocarbons such as toluene and xylene, amides such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone. These solvents may be used alone or in combination of two or more.

The amount of solvent used is preferably 10 to 80% by mass, more preferably 20 to 70% by mass, relative to the total mass of the composition. It is preferable that the amount of the solvent used is 10% by mass or more because the handleability is excellent. On the other hand, when the amount of the solvent used is 80% by mass or less, the impregnating property with other substrates is excellent, which is preferable.

<Additive>
The composition of the present invention may contain additives. Such additives include curing accelerators, flame retardants, fillers, and the like.

<Curing accelerator>
The curing accelerator is not particularly limited as long as it accelerates the curing reaction between the active ester compound and the epoxy resin. Phosphorus curing accelerators, amine curing accelerators, imidazole curing accelerators, and guanidine curing accelerators. Accelerators, urea-based curing accelerators, and the like.

Examples of the phosphorus curing accelerator include organic phosphine compounds such as triphenylphosphine, tributylphosphine, tripparatolylphosphine, diphenylcyclohexylphosphine and tricyclohexylphosphine; organic phosphine compounds such as trimethylphosphite and triethylphosphite; ethyltriphenyl phosphonium bromide, benzyltriphenylphosphonium chloride, butylphosphonium tetraphenylborate, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra-p-tolylborate, triphenylphosphine triphenylborane, tetraphenylphosphonium thiocyanate, tetraphenylphosphonium dicyanamide, Examples include phosphonium salts such as butylphenylphosphonium dicyanamide and tetrabutylphosphonium decanoate.

Amine curing accelerators include triethylamine, tributylamine, N,N-dimethyl-4-aminopyridine (DMAP), 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diazabicyclo[5,4 ,0]-undecene-7 (DBU), 1,5-diazabicyclo[4,3,0]-nonene-5 (DBN) and the like.

Examples of imidazole curing accelerators include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl- 4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl- 4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2- methyl-3-benzylimidazolium chloride, 2-methylimidazoline and the like.

Guanidine curing accelerators include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5 , 7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-butylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide, 1-phenylbiguanide and the like.

Examples of the urea curing accelerator include 3-phenyl-1,1-dimethylurea, 3-(4-methylphenyl)-1,1-dimethylurea, chlorophenylurea, 3-(4-chlorophenyl)-1,1 -dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea and the like.

Of the above curing accelerators, it is preferable to use 2-ethyl-4-methylimidazole and 4-dimethylaminopyridine (DMAP). In addition, the above curing accelerators may be used alone or in combination of two or more.

The amount of curing accelerator used is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, based on 100 parts by mass of the epoxy resin. It is preferable that the amount of the curing accelerator used is 0.01 parts by mass or more because the curability is excellent. On the other hand, when the amount of the curing accelerator used is 5 parts by mass or less, the moldability is excellent, which is preferable.

<Flame retardant>
The flame retardant is not particularly limited, but includes inorganic phosphorus flame retardants, organic phosphorus flame retardants, halogen flame retardants, and the like.

The inorganic phosphorus-based flame retardant is not particularly limited, but includes red phosphorus; ammonium phosphates such as monoammonium phosphate, diammonium phosphate, triammonium phosphate, and ammonium polyphosphate; and phosphate amides.

The organic phosphorus flame retardant is not particularly limited, but methyl acid phosphate, ethyl acid phosphate, isopropyl acid phosphate, dibutyl phosphate, monobutyl phosphate, butoxyethyl acid phosphate, 2-ethylhexyl acid phosphate, bis(2-ethylhexyl) phosphate, monoisodecyl acid phosphate, lauryl acid phosphate, tridecyl acid phosphate, stearyl acid phosphate, isostearyl acid phosphate, oleyl acid phosphate, butylpyrophosphate, tetracosyl acid phosphate, ethylene glycol acid phosphate, (2-hydroxyethyl ) Phosphate esters such as methacrylate acid phosphate; 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, diphenylphosphine oxide and the like diphenylphosphine; 9-oxa-10-phosphaphenanthrene-10-oxide, 10-(1,4-dioxynaphthalene)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, diphenylphosphinylhydroquinone, diphenylphosphine Phosphorus-containing phenols such as phenyl-1,4-dioxynaphthalene, 1,4-cyclooctylenephosphinyl-1,4-phenyldiol and 1,5-cyclooctylenephosphinyl-1,4-phenyldiol 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, 10 Cyclic phosphorus compounds such as -(2,7-dihydroxynaphthyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide; Aldehyde compounds, compounds obtained by reacting with phenol compounds, and the like.

The halogen-based flame retardant is not particularly limited, but brominated polystyrene, bis(pentabromophenyl)ethane, tetrabromobisphenol A bis(dibromopropyl ether), 1,2-bis(tetrabromophthalimide), 2,4 ,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine, tetrabromophthalic acid and the like.

The above flame retardants may be used alone or in combination of two or more.

The amount of the flame retardant used is preferably 0.1 to 50 parts by mass, more preferably 1 to 30 parts by mass, based on 100 parts by mass of the epoxy resin. It is preferable that the amount of the flame retardant used is 0.1 parts by mass or more because flame retardancy can be imparted. On the other hand, when the amount of the flame retardant used is 50 parts by mass or less, it is preferable because flame retardancy can be imparted while maintaining dielectric properties.

<Filler>
Examples of fillers include organic fillers and inorganic fillers. A filler has a function of improving elongation, a function of improving mechanical strength, and the like.

The organic filler is not particularly limited, but may include polyamide particles and the like.

The inorganic filler is not particularly limited, but silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, nitride Boron, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium zirconate titanate, barium zirconate , calcium zirconate, zirconium phosphate, zirconium tungstate phosphate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, carbon black and the like.

Of these, it is preferable to use silica. At this time, as silica, amorphous silica, fused silica, crystalline silica, synthetic silica, hollow silica, and the like can be used.

In addition, the filler may be surface-treated as necessary. Surface treatment agents that can be used at this time are not particularly limited, but aminosilane coupling agents, epoxysilane coupling agents, mercaptosilane coupling agents, silane coupling agents, organosilazane compounds, and titanate coupling agents. agents and the like can be used. Specific examples of surface treatment agents include 3-glycidoxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, hexamethyldimethoxysilane, silazane and the like.

The above fillers may be used alone or in combination of two or more.

The average particle size of the filler is not particularly limited, and is preferably 0.01 to 10 µm, more preferably 0.03 to 5 µm, even more preferably 0.05 to 3 µm. As used herein, the term "particle size" means the maximum length of the distances between two points on the contour line of the particle. In addition, the "average particle size" is measured by measuring the particle size of arbitrary 100 particles in one screen in an image obtained by a scanning electron microscope (SEM) and calculating the average value. shall be adopted.

The amount of filler used is preferably 0.5 to 95 parts by mass, more preferably 5 to 80 parts by mass, based on 100 parts by mass of the epoxy resin. It is preferable that the amount of the filler used is 0.5 parts by mass or more because low thermal expansion can be imparted. On the other hand, when the amount of filler used is 95 parts by mass or less, it is preferable because the balance between properties and moldability is excellent.

<Cured product (cured product of epoxy resin composition)>
The cured product of the present invention is a cured product obtained by curing the composition described above. That is, it is obtained by curing at least the active ester compound and the epoxy resin. Since the cured product of the present invention is excellent in dielectric loss tangent, it can be used for electronic material applications such as semiconductor package substrates, printed wiring boards, build-up adhesive films, and semiconductor sealing materials. In addition, it can also be applied to uses such as adhesives and paints.

The heating temperature for heat-curing the composition is not particularly limited, but is preferably 150 to 300°C. It is more preferably 175 to 250°C, still more preferably 180 to 200°C. Further, the heating time depends on the heating temperature, but is preferably 30 minutes to 10 hours, more preferably 1 to 5 hours.

The dielectric loss tangent (tan δ) of the cured product of the present invention at a frequency of 10 GHz is preferably 0.007 or less. It is more preferably 0.006 or less, still more preferably 0.005 or less, because it is suitable for electronic material applications. Although the lower limit of the dielectric loss tangent (tan δ) is not particularly limited, it may be industrially 0.001 or more, or 0.002 or more.

The dielectric constant (ε _c ) of the cured product of the present invention at a frequency of 10 GHz is preferably 2.85 or less. It is more preferably 2.82 or less, still more preferably 2.80 or less, because it is suitable for electronic material applications. The lower limit of the dielectric constant (ε _c ) is not particularly limited, but may be industrially 2.00 or more, or 2.50 or more.

The present invention will be described below using examples, but the present invention is not limited to the description of the examples.

[Synthesis Example 1]
A flask equipped with a thermometer, a dropping funnel, a condenser, a fractionating tube and a stirrer was charged with 250 g (1.1 mol) of isophthalic acid dichloride, and the atmosphere in the system was replaced with nitrogen under reduced pressure. Next, the inside of the system was controlled at 100° C. to dissolve the isophthalic acid dichloride, and then 12 g (0.1 mol) of phenol was dissolved in 20 ml of chloroform and added dropwise over 15 minutes. After the dropwise addition was completed, the temperature was raised to 140° C. and the mixture was stirred for 2.0 hours. After completion of the reaction, unreacted isophthaloyl dichloride was removed by heating under reduced pressure to obtain a compound (A-1) represented by the following chemical formula.

[Synthesis Example 2]
A compound (A-2) represented by the following chemical formula was obtained in the same manner as in Example 1, except that 18 g (0.1 mol) of 2-naphthol was used instead of phenol.

[Production Example 1]
A flask equipped with a thermometer, a dropping funnel, a condenser, a fractionating tube and a stirrer was charged with 15 g (29 mmol) of dimer diol P2033 (manufactured by CRODA) and 100 g of THF, and the inside of the system was replaced with nitrogen under reduced pressure. After adding 9 g (86 mmol) of triethylamine, 15 g (58 mmol) of compound (A-1) was added dropwise. While purging with nitrogen gas, the inside of the system was controlled at 55° C. and stirred for 3.0 hours. After completion of the reaction, the product was washed with 200 g of water three times, and the organic solvent was removed by heating under reduced pressure to obtain an active ester compound 1.

[Production Example 2]
Active ester compound 2 was obtained in the same manner as in Production Example 1, except that 18 g (58 mmol) of compound (A-2) was used instead of compound (A-1).

[Production Example 3]
A flask equipped with a thermometer, a dropping funnel, a condenser, a fractionating tube and a stirrer was charged with 9 g (38 mmol) of bisphenol A and 100 g of THF, and the inside of the system was replaced with nitrogen under reduced pressure. After adding 9.3 g (92 mmol) of triethylamine, 20 g (77 mmol) of compound (A-1) was added dropwise. While purging with nitrogen gas, the inside of the system was controlled at 60° C. and stirred for 3.0 hours. After completion of the reaction, the product was washed with 200 g of water three times, and the organic solvent was removed by heating under reduced pressure to obtain an active ester compound (A-3) represented by the following chemical formula.

[Production Example 4]
An active ester compound represented by the following chemical formula (A- 4) was obtained.

[Example 1]
32 parts by mass of jER (registered trademark) 152 (manufactured by Mitsubishi Chemical Corporation), 18 parts by mass of active ester compound 1, 50 parts by mass of active ester compound 3, 0.05 parts by mass of 4-dimethylaminopyridine, a mixer and dispersed uniformly to obtain a resin composition. The resulting resin composition was poured into a mold (100 mm×3 mm×1 mm) and cured by heating at 110° C. for 1 hour. Then, after heat pressing at 180° C. and 3 MPa for 10 minutes, heat curing was performed at 180° C. for 3 hours to obtain a cured product (measurement sample) 1.

[Example 2] to [Example 8], [Comparative Example 1] to [Comparative Example 2]
Using the reagents shown in Table 1, compositions 2 to 10 and cured products 2 to 10 were prepared in the same manner as in Example 1, and Examples 2 to 8 and Comparative Examples 1 and 2 were performed.
In addition, jER (registered trademark) 152 (manufactured by Mitsubishi Chemical Corporation) is a phenol novolak type epoxy resin, jER (registered trademark) 828 (manufactured by Mitsubishi Chemical Corporation) is a bisphenol A type epoxy resin, Tetrad (registered trademark) )-X (manufactured by Mitsubishi Gas Chemical Company, Inc.) is N,N,N',N'-tetraglycidyl-m-xylenediamine.

(relative permittivity and dielectric loss tangent)
The dielectric constant and the dielectric loss tangent were measured by the cavity resonance method using a network analyzer MS46122B (manufactured by Anritsu Corporation) under conditions of a temperature of 23° C. and a frequency of 10 GHz. The results obtained are shown in Table 1 below.

(Heat-resistant)
Heat resistance was measured from 0° C. to 300° C. using DVA-200 (manufactured by IT Keisoku Co., Ltd.) at a frequency of 1 Hz and a heating rate of 3° C./min to determine the glass transition temperature (Tg). . The results obtained are shown in Table 1 below.

[evaluation]
Cured products 1 to 10 produced in Examples 1 to 8 and Comparative Examples 1 to 2 were used to measure dielectric constant, dielectric loss tangent and heat resistance.

From the results in Table 1, by combining the active esters (B-1) and (B-2) as in Examples 1 to 8, the dielectric properties are significantly improved compared to those used alone in Comparative Examples 1 to 2. It can be seen that good results were obtained in which the heat resistance was reduced and the heat resistance was improved.

Claims

containing an epoxy resin (A), a first active ester compound (B-1) and a second active ester compound (B-2),
An epoxy resin composition, wherein the first active ester compound (B-1) is an active ester compound having a dimer acid skeleton and/or a dimer diol skeleton in its molecule.
The epoxy resin composition according to claim 1, wherein the ratio of the first active ester compound (B-1) to the total active ester compound is 20 to 80% by mass.
The second active ester compound (B-2) is a reaction product of an aromatic polyhydroxy compound, an aromatic polycarboxylic acid compound or its acid halide, and an aromatic monohydroxy compound. The epoxy resin composition according to claim 1 or 2.
The terminal structure of the first active ester compound (B-1) is the formula (1) or the formula (2)

(In the formula, each R is independently an aliphatic hydrocarbon group, an alkoxy group, a halogen atom, an aryl group, or an aralkyl group, n is an integer of 0 to 5, and m is an integer of 0 to 7. .) The epoxy resin composition according to claim 1 or 2, which is an active ester compound represented by:
The epoxy resin composition according to claim 1 or 2, wherein the first active ester compound (B-1) has a molecular weight of 500 to 5,000.
The aromatic polyhydroxy compound constituting the second active ester compound (B-2) is the following (X-1) to (X-4)

(in the formula, each X is independently hydrogen or a methyl group; i is 1 or 2);
A cured product of the epoxy resin composition according to claim 1 or 2.