Epoxy resin, epoxy resin composition, and cured object, prepreg, laminate, and printed wiring board obtained from epoxy resin composition, and method for producing epoxy resin

Abstract

Provided are an epoxy resin composition giving cured objects exhibiting excellent low-dielectric characteristics, an epoxy resin giving the epoxy resin composition and having low melt viscosity, and a method for producing the epoxy resin.　The epoxy resin is characterized in that: the epoxy resin comprises an epoxy resin component (A) represented by general formula (1) and an epoxy resin component (B) represented by general formula (5a) or (5b); and, in measurement by gel permeation chromatography, the content of the epoxy resin component (B) is in the range of 10-90% by area.　[Chemical formula 1] (In formula (1), the X moieties are independently a divalent group including a group represented by formula (2), (3a), or (3b), wherein at least one of the X moieties is a group represented by formula (2); the Z moieties independently represent a glycidyl group or a group represented by formula (4a) or (4b), with the proviso that at least one of the Z moieties in formulae (1) and (2) is a glycidyl group; and n indicates the number of repetitions, and is a number of 0-10 on average.)

Description

Epoxy resin, epoxy resin composition, cured product, prepreg, laminate and printed wiring board using the epoxy resin composition, and method for producing epoxy resin

[0001] The present invention relates to an epoxy resin that gives a cured product having excellent low dielectric properties, an epoxy resin composition containing the epoxy resin as an essential component, a cured product, a prepreg, a laminate and a printed wiring board obtained from the epoxy resin composition, and a method for producing the epoxy resin.

[0002] Epoxy resins have excellent adhesive properties, flexibility, heat resistance, chemical resistance, insulating properties, and curing reactivity, and are therefore used in a wide range of applications, including paints, civil engineering adhesives, casting, electrical and electronic materials, film materials, etc. In particular, epoxy resins are widely used in printed wiring boards, one type of electrical and electronic material, by imparting flame retardancy to them.

[0003] In recent years, information devices have rapidly become smaller and more powerful, and as a result, materials used in the fields of semiconductors and electronic components are required to have higher performance than ever before. In particular, epoxy resin compositions used as materials for electric and electronic components are required to have low dielectric properties in response to the trend toward thinner substrates and higher functionality.

[0004] On the other hand, epoxy resins are required to have not only low dielectric properties but also low melt viscosity to ensure the embeddability of circuits on substrates. To date, dicyclopentadiene phenol resins incorporating an aliphatic skeleton have been proposed as an approach to improving the dielectric properties of epoxy resins for laminate applications (Patent Documents 1 and 2). However, these have been poorly effective in improving the dielectric loss tangent, and the low melt viscosity has not been satisfactory. Furthermore, the use of modified dicyclopentadiene phenol resins has been proposed to improve dielectric properties (Patent Documents 3 and 4). However, these have not achieved both low dielectric properties and low melt viscosity. Furthermore, the epoxidation of a mixture of a polycondensate of dicyclopentadiene with phenol and / or cresol and a bisphenol has been proposed to improve melt viscosity (Patent Documents 5 and 6). However, the low melt viscosity has not been satisfactory.

[0005] Japanese Patent Application Laid-Open No. 2001-240654 Japanese Patent Application Laid-Open No. 5-339341 Japanese Patent Application Laid-Open No. 2016-69524 International Publication No. 2020 / 129724 Japanese Patent No. 5246760 Japanese Patent No. 5299976

[0006] Therefore, an object of the present invention is to provide an epoxy resin that satisfies both low dielectric properties and low melt viscosity and can give a cured product that exhibits excellent dielectric properties, an epoxy resin composition using the same, and a method for producing the same.

[0007] As a result of extensive investigations conducted by the present inventors to solve the above problems, it was found that an epoxy resin obtained by epoxidizing a mixture of a specific dicyclopentadiene-type polyhydric hydroxy resin and a phenolic compound having a specific structure has a low melt viscosity, and that a cured product obtained from an epoxy resin composition containing this epoxy resin as an essential component has excellent low dielectric properties, and this has led to the completion of the present invention.

[0008] That is, the present invention provides an epoxy resin comprising an epoxy resin component (A) represented by the following general formula (1) and an epoxy resin component (B) represented by the following general formula (5a) or (5b), wherein the content of the epoxy resin component (B) is in the range of 10 to 90 area % as measured by gel permeation chromatography: Here, X is independently a divalent group containing a group represented by the following formula (2), (3a), or (3b), at least one of which is a group represented by formula (2). Z independently represents a glycidyl group or a group represented by the following formula (4a) or (4b), provided that at least one of Z in formula (1) and formula (2) is a glycidyl group. n represents the number of repetitions, and its average value is a number from 0 to 10. Here, R １ R independently represents a hydrocarbon group having 1 to 10 carbon atoms, i is an integer from 1 to 4, and 4-i and 3-i are both 0 or more. ２ each independently represents a hydrogen atom or a group represented by formula (2a) or formula (2b), and at least one of them is formula (2a) or formula (2b). m1 represents the number of repetitions, and the average value is 0.01 to 5. Here, R ３are independently a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a group represented by formula (2a) or formula (2b), and j is 1 to 4 and may be the same or different groups. Y is a direct bond, an alkylene group which may have a substituent, or an alkylene group which may have an aromatic group. The substituent is a hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom. Here, R ３ independently represent a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a group represented by formula (2a) or formula (2b), and q is 1 to 4 and may be the same or different groups. G represents a glycidyl group, and s1 is 0 or 1. Y represents a direct bond, an alkylene group which may have a substituent, or an alkylene group which may have an aromatic group. The substituent is a hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom. Here, R ３ independently represent a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a group represented by formula (2a) or formula (2b), and may be the same or different groups. G represents a glycidyl group, s2 is 1 or 2, s3 is an integer of 1 to 5, and s2 + s3 is an integer of 2 to 6. Y represents a direct bond, an alkylene group which may have a substituent, or an alkylene group which may have an aromatic group. The substituent is a hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom.

[0009] The melt viscosity of the epoxy resin at 150° C. is preferably 0.001 to 0.10 Pa·s.

[0010] The present invention also provides an epoxy resin composition containing an epoxy resin and a curing agent, characterized in that the epoxy resin is the above-mentioned epoxy resin as an essential component. The curing agent is preferably a polyhydric hydroxy resin represented by the following general formula (6) or an active ester resin: Here, R １ R independently represents a hydrocarbon group having 1 to 10 carbon atoms, i is an integer of 1 to 4, and 4-i and 3-i are both 0 or more. ２１each independently represents a hydrogen atom or a group represented by formula (6a) or formula (6b), and at least one of them is formula (6a) or formula (6b). m3 represents the number of repetitions, and its average value is 0 to 5.

[0011] The present invention also relates to a cured product obtained by curing the above-mentioned epoxy resin composition. The present invention also relates to a prepreg, a laminate, or a printed wiring board using the above-mentioned epoxy resin composition.

[0012] The present invention also provides a method for producing the above-mentioned epoxy resin, characterized in that 1 mole of phenolic hydroxyl groups in a mixture obtained by blending 100 parts by mass of the polyhydric hydroxy resin represented by the above general formula (6) with 10 to 300 parts by mass of a phenol compound represented by the following general formula (7a) or (7b) are reacted with 1 to 20 moles of epihalohydrin in the presence of an alkali metal hydroxide: Here, R ３ independently represent a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a group represented by formula (2a) or formula (2b), and may be the same or different groups. q1 is 1 or 2, q2 is an integer from 1 to 4, and q1 + q2 is an integer from 2 to 6. Y represents a direct bond, an alkylene group which may have a substituent, or an alkylene group which may have an aromatic group. The substituent is a hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom. q3 is 1 or 2, q4 is an integer from 1 to 5, and q3 + q4 is an integer from 2 to 6.

[0013] The epoxy resin of the present invention has a low melt viscosity, and an epoxy resin composition using this epoxy resin gives a cured product that exhibits excellent low dielectric properties.

[0014] 1 is a GPC chart of the epoxy resin obtained in Example 1. FIG. 2 is an IR chart of the epoxy resin obtained in Example 1.

[0015] Hereinafter, embodiments of the present invention will be described in detail. The epoxy resin of the present invention contains, as essential components, an epoxy resin component (A) represented by the following general formula (1) and an epoxy resin component (B) represented by the following general formula (5a) or (5b). Furthermore, as measured by gel permeation chromatography, the epoxy resin component (B) accounts for 10 to 90 area %. Preferably, the epoxy resin component (B) accounts for 30 to 85 area %.

[0016] Here, the epoxy resin component (B) includes not only epoxidized products of phenolic compounds having a specific structure represented by general formula (7a) or (7b) used as raw materials, but also epoxidized products of polyhydric hydroxy resins represented by general formula (6) in which m3 is 0 (zero) (m3 = 0 form). This is because the epoxidized products of polyhydric hydroxy resins represented by general formula (6) in which m3 = 0 is synonymous with general formula (5b), and are therefore included in the epoxy resin component (B).

[0017]

[0018] In general formula (1), X is independently a divalent group containing a group represented by formula (2), (3a), or (3b) below, at least one of which is a group represented by formula (2). Z independently represents a glycidyl group or a group represented by formula (4a) or (4b) below. However, at least one of Z in formula (1) and formula (2) is a glycidyl group. n represents the number of repetitions, and its average value is a number from 0 to 10, preferably 0 to 5. A more preferred average value of n is 0.01 to 3.0.

[0019] In general formula (5a) or (5b), R ３are independently a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a group represented by formula (2a) or formula (2b), and may be the same or different groups. G is a glycidyl group, s2 is 1 or 2, s3 is an integer from 1 to 5, and s2+s3 is an integer from 2 to 6. Y is a direct bond, an alkylene group which may have a substituent, or an alkylene group which may have an aromatic group. Here, the substituent is a hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom. The "hydrocarbon group having 1 to 10 carbon atoms" includes, for example, R in formula (2) described below. １ Examples of the aromatic group include the groups exemplified above. Examples of the aromatic group include groups exemplified below that contain a heteroatom as a part of the group. Examples of the aromatic group include monovalent or divalent aromatic groups derived from aromatic compounds.

[0020]

[0021] In formula (2), R １ R represents a hydrocarbon group having 1 to 10 carbon atoms, and is preferably an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 8 carbon atoms, an aralkyl group having 7 to 8 carbon atoms, or an allyl group. The alkyl group having 1 to 10 carbon atoms may be linear, branched, or cyclic, and examples thereof include, but are not limited to, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a t-butyl group, a hexyl group, a cyclohexyl group, and a methylcyclohexyl group. Examples of aryl groups having 6 to 8 carbon atoms include, but are not limited to, a phenyl group, a tolyl group, a xylyl group, and an ethylphenyl group. Examples of aralkyl groups having 7 to 8 carbon atoms include, but are not limited to, a benzyl group and an α-methylbenzyl group. Among these substituents, phenyl and methyl groups are preferred, with methyl being particularly preferred, from the viewpoints of availability and reactivity when formed into a cured product. １ The substitution position may be any of the ortho, meta, and para positions, but the ortho position is preferred.

[0022] R ２ represents a hydrogen atom or a group represented by formula (2a) or formula (2b), and at least one of R is represented by formula (2a) or formula (2b). ２ is a substituent R１ Unlike the above, it does not necessarily represent only a substituent, but also a hydrogen atom.

[0023] i is a substituent R １ is an integer of 1 to 4, preferably 1 or 2, and more preferably 2. In this case, 3-i and 4-i are preferably 0 or more.

[0024] Z in formula (2) has the same meaning as Z in formula (1).

[0025] m1 represents the number of repetitions, and the average value (number average) is a number of 0.01 to 5, preferably 0.01 to 3.0, more preferably 0.01 to 2.5, and even more preferably 0.01 to 2.0.

[0026] In formula (3a) and formula (3b), R ３ are independently a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a group represented by formula (2a) or formula (2b), and j is 1 to 4, and may be the same or different groups. Examples of the hydrocarbon group having 1 to 10 carbon atoms include R １ Examples include the same as those shown below. ３ From the viewpoints of availability and heat resistance of the cured product, j is preferably a hydrogen atom, a methyl group, an ethyl group, or a dicyclopentadiene group represented by formula (2a) or formula (2b), and more preferably a hydrogen atom, a methyl group, or the dicyclopentadiene group. ３ and is a number of 1 to 4, preferably 1 to 3. Y represents a direct bond or an alkylene group which may have a substituent. The substituent is a hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom.

[0027]

[0028] In formula (4a) and formula (4b), R ３ is R in formula (3a) and formula (3b) ３ q is the same as the substituent R ３is a number of 1 to 4, preferably 1 to 3. s1 is 0 or 1. Y represents a direct bond, an alkylene group which may have a substituent, or an alkylene group which may have an aromatic group. The substituent is a hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom.

[0029] The epoxy resin of the present invention is preferably obtained by epoxidizing a mixture of a polyhydric hydroxy resin represented by the following general formula (6) and a phenol compound having a specific structure represented by the following general formula (7a) or formula (7b). As can be seen from the above descriptions of epoxy resin component (A) and epoxy resin component (B), preferably, when m3 in formula (6) is 1 or greater, X in formula (1) has the structure represented by formula (2). Epoxy resin component (A) can be obtained by epoxidizing such a polyhydric hydroxy resin. Epoxy resin component (B) can be obtained by epoxidizing a polyhydric hydroxy resin in which m3 is 0 in formula (6) or a phenol compound having the specific structure represented by formula (7a) or (7b).

[0030] In this case, the epoxy resin component (A) may adopt a structure having a group represented by the formula (4a) or (4b) as the Z group, which is believed to be due to the following reaction mechanism: That is, two raw materials, the polyhydric hydroxy resin and a phenolic compound having a specific structure, are mixed and reacted with epichlorohydrin (epoxidation), and during the reaction, a proton is abstracted from the hydroxyl group of the phenolic compound that has not been epoxidized by a base, which reacts with the previously epoxidized polyhydric hydroxy resin, resulting in the Z group having the structure of the formula (4a) or (4b).

[0031]

[0032] In general formula (6), R １ , i is R in formula (2) １ , i respectively. ２１each independently represents a hydrogen atom or a group represented by formula (6a) or formula (6b), and at least one is formula (6a) or formula (6b). m3 represents the number of repetitions, the average value of which is a number of 0 to 5. m3 is preferably 0.01 to 3.0, more preferably 0.01 to 2.5, and even more preferably 0.01 to 2.0.

[0033] In formula (7a), R ３ is R in formula (3a) and formula (3b) ３ q1 is the number of hydroxyl groups and is 1 or 2, and q2 is the substituent R ３ and q1+q2 is an integer of 1 to 4, preferably an integer of 1 to 3, and q1+q2 is an integer of 2 to 6, preferably an integer of 2 to 4. Y represents a direct bond, an alkylene group which may have a substituent, or an alkylene group which may have an aromatic group. The substituent is a hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom. In formula (7b), q3 is the number of hydroxyl groups and is 1 or 2, and q4 is the number of substituents R ３ and q3+q4 is an integer of 1 to 5, preferably an integer of 1 to 3, and q3+q4 is an integer of 2 to 6, preferably an integer of 2 to 4.

[0034] The polyhydric hydroxy resin represented by general formula (6) can be produced by a known method, for example, the production method disclosed in Patent Document 4.

[0035] In the polyhydric hydroxy resin represented by general formula (6), R ２１ As a method for confirming that a dicyclopentenyl group represented by formula (6a) or formula (6b) has been introduced as a substituent represented by formula (6a), mass spectrometry and FT-IR measurement can be used.

[0036] When mass spectrometry is used, electrospray ionization mass spectrometry (ESI-MS), field desorption mass spectrometry (FD-MS), etc. can be used. By subjecting a sample obtained by separating components with different numbers of nuclei using GPC or the like to mass spectrometry, it is possible to confirm that a dicyclopentenyl group has been introduced.

[0037] When the FT-IR measurement method is used, the sample is mounted on a diamond ATR and measured by FT-IR, and a peak due to the C—O stretching vibration of the phenol nucleus is observed at 1210 cm －１ Only when a dicyclopentenyl group is introduced does the peak due to the C-H stretching vibration of the olefin moiety of the dicyclopentadiene skeleton appear at 3040 cm －１ It appears around 3040 cm. Incidentally, since the dicyclopentenyl group used as the linking group of phenols is not an olefin, this absorption peak does not appear. When the baseline is a linear connection between the start and end of the target peak, and the length from the peak apex to the baseline is the peak height, it is 3040 cm. －１ Nearby peaks (A ３０４０ ) and 1210 cm －１ Nearby peaks (A １２１０ ) ratio (A ３０４０ / A １２１０ The amount of dicyclopentenyl groups introduced can be quantified by the ratio. It has been confirmed that the larger the ratio, the better the physical properties. ３０４０ / A １２１０ ) is 0.01 or more, more preferably 0.05 or more, and even more preferably 0.10 or more. The upper limit is preferably 0.70 or less, more preferably 0.60 or less. If this ratio is high, it means that a large number of dicyclopentenyl groups have been introduced. The amount of dicyclopentenyl groups introduced can be quantified by this ratio.

[0038] The phenolic hydroxyl group equivalent (g / eq.) of the polyhydric hydroxy resin represented by formula (6) is preferably 160 to 400, more preferably 180 to 380, and even more preferably 200 to 360. The content by GPC of m3=0 is preferably in the range of 80 area % or less.

[0039] The phenolic hydroxyl group equivalent (g / eq.) of the phenolic compounds having the specific structures represented by formula (7a) and formula (7b) is preferably 80 to 260.

[0040] Examples of phenol compounds having a specific structure represented by formula (7a) or formula (7b) include cresol, ethylphenol, propylphenol, isopropylphenol, n-butylphenol, t-butylphenol, hexylphenol, cyclohexylphenol, phenylphenol, tolylphenol, benzylphenol, α-methylbenzylphenol, allylphenol, dimethylphenol, t-butyl-dimethylphenol, diethylphenol, dipropylphenol, diisopropylphenol, di(n-butyl)phenol, di(t-butyl)phenol, dihexylphenol, dicyclohexylphenol, diphenylphenol, Examples of suitable bisphenols include phenylphenol, ditolylphenol, dibenzylphenol, bis(α-methylbenzyl)phenol, methylethylphenol, methylpropylphenol, methylisopropylphenol, methylbutylphenol, methyl-t-butylphenol, methylallylphenol, tolylphenylphenol, t-butylcatechol, t-butylresorcinol, t-butylhydroquinone, bisphenol F, bisphenol A, bisphenol C, bisphenol M, bisphenol P, tetramethylbisphenol F, tetramethylbisphenol A, 3,3',5,5'-tetramethylbiphenyl-4,4'-diol, etc. From the viewpoints of ease of availability and reactivity when formed into a cured product, t-butylcatechol, bisphenol F, bisphenol A, bisphenol C, bisphenol M, bisphenol P, tetramethylbisphenol F, tetramethylbisphenol A, and 3,3',5,5'-tetramethylbiphenyl-4,4'-diol are preferred.

[0041] As raw materials for the epoxy resin of the present invention, phenolic compounds other than the polyhydric hydroxy resin and the phenolic compound having the specific structure described above as essential components can also be used in combination, as long as they do not inhibit the effects of the epoxy resin of the present invention. The phenolic compounds that can be used in combination are preferably monohydric or dihydric compounds. The amount that can be used in combination is preferably in the range of 10% by mass to 90% by mass based on the total amount of the phenolic compound components.

[0042] The epoxy resin of the present invention contains an epoxy resin component (A) represented by general formula (1) and an epoxy resin component (B) represented by general formula (5a) or (5b). This epoxy resin can be suitably obtained by reacting an epihalohydrin such as epichlorohydrin with a mixture of a polyhydric hydroxy resin represented by general formula (6) and a phenol compound represented by general formula (7a) or (7b). This epoxidation reaction is carried out according to a conventionally known method.

[0043] The epoxidation method can be, for example, to prepare the polyhydric hydroxy resin and phenolic compound as raw materials, and an excess molar amount of epihalohydrin relative to the total hydroxyl groups of the polyhydric hydroxy resin and phenolic compound, and then add an alkali metal hydroxide such as sodium hydroxide as a solid or concentrated aqueous solution to this mixture of reaction raw materials, and react for 0.5 to 10 hours at a reaction temperature of 30 to 120° C. Alternatively, the polyhalohydrin ether can be obtained by adding a quaternary ammonium salt such as tetraethylammonium chloride as a catalyst to the mixture of reaction raw materials, and reacting at a temperature of 50 to 150° C. for 1 to 5 hours to obtain a polyhalohydrin ether, to which an alkali metal hydroxide such as sodium hydroxide as a solid or concentrated aqueous solution is then added, and then reacting for 1 to 10 hours at a temperature of 30 to 120° C.

[0044] In the above reaction, the amounts of the polyhydric hydroxy resin and the phenol compound used are preferably 10 to 300 parts by mass of the phenol compound per 100 parts by mass of the polyhydric hydroxy resin, and more preferably 10 to 250 parts by mass of the phenol compound per 100 parts by mass of the polyhydric hydroxy resin. The amount of epihalohydrin used is 1 to 20 times, and preferably 2 to 8 times, the molar amount of the total hydroxyl groups in the mixture of the polyhydric hydroxy resin and the phenol compound. The amount of alkali metal hydroxide used is preferably 0.85 to 1.15 times the molar amount of the total hydroxyl groups in the mixture of the polyhydric hydroxy resin and the phenol compound.

[0045] The epoxy resin obtained by these reactions contains unreacted epihalohydrin and alkali metal halide, so the desired epoxy resin can be obtained by removing the unreacted epihalohydrin from the reaction mixture by evaporation, and then removing the alkali metal halide by extraction with water, filtration, or other methods.

[0046] The epoxy equivalent (g / eq.) of the epoxy resin of the present invention is preferably 160 to 400, more preferably 170 to 360, and even more preferably 180 to 340. The melt viscosity at 150°C is preferably 0.001 to 0.10 Pa·s, and more preferably 0.001 to 0.05 Pa·s. The weight average molecular weight (Mw) is preferably 200 to 2000, more preferably 300 to 1000, and the number average molecular weight (Mn) is preferably 100 to 1000, and more preferably 150 to 800. The total chlorine content is preferably 2000 ppm or less, and more preferably 1500 ppm or less.

[0047] The epoxy resin composition of the present invention contains an epoxy resin and a curing agent, and the epoxy resin of the present invention is an essential component. In this embodiment, part or all of the epoxy resin is the epoxy resin of the present invention.

[0048] Preferably, the epoxy resin of the present invention accounts for 30% by mass or more of the epoxy resin, more preferably 50% by mass or more, and even more preferably 70% by mass or more. If the content is less than this, the dielectric properties may be deteriorated.

[0049] As the epoxy resin used in the epoxy resin composition of the present invention, one or more of various epoxy resins may be used in combination with the epoxy resin of the present invention, if necessary. The amount that can be used in combination is preferably less than 50% by mass, more preferably less than 10% by mass, based on the total amount of the epoxy resin.

[0050] As various epoxy resins that can be used in combination, all common epoxy resins having two or more epoxy groups in the molecule can be used.Examples include trifunctional epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, tetramethylbisphenol F type epoxy resins, hydroquinone type epoxy resins, biphenyl type epoxy resins, stilbene type epoxy resins, bisphenol fluorene type epoxy resins, bisphenol S type epoxy resins, bisthioether type epoxy resins, resorcinol type epoxy resins, biphenylaralkylphenol type epoxy resins, naphthalenediol type epoxy resins, phenol novolac type epoxy resins, aromatic modified phenol novolac type epoxy resins, cresol novolac type epoxy resins, alkyl novolac type epoxy resins, bisphenol novolac type epoxy resins, binaphthol type epoxy resins, naphthol novolac type epoxy resins, β-naphthol aralkyl type epoxy resins, dinaphthol aralkyl type epoxy resins, α-naphthol aralkyl type epoxy resins, trisphenylmethane type epoxy resins, and tetrafunctional epoxy resins such as tetrakisphenylethane type epoxy resins. Examples of epoxy resins that may be used include, but are not limited to, dicyclopentadiene-type epoxy resins other than those of the present invention, polyhydric alcohol polyglycidyl ethers such as 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, trimethylolethane polyglycidyl ether, and pentaerythritol polyglycidyl ether, alkylene glycol-type epoxy resins such as propylene glycol diglycidyl ether, aliphatic cyclic epoxy resins such as cyclohexanedimethanol diglycidyl ether, glycidyl esters such as dimer acid polyglycidyl ester, glycidyl amine-type epoxy resins such as phenyl diglycidyl amine, tolyl diglycidyl amine, diaminodiphenylmethane tetraglycidyl amine, and aminophenol-type epoxy resins, alicyclic epoxy resins such as CELLOXIDE 2021P (manufactured by Daicel Corporation), phosphorus-containing epoxy resins, bromine-containing epoxy resins, urethane-modified epoxy resins, and oxazolidone ring-containing epoxy resins. These epoxy resins may be used alone or in combination of two or more.From the viewpoint of availability, it is more preferable to use an epoxy resin represented by the following general formula (8), or a dicyclopentadiene-type epoxy resin, a naphthalenediol-type epoxy resin, a phenol novolac-type epoxy resin, an aromatic-modified phenol novolac-type epoxy resin, a cresol novolac-type epoxy resin, an α-naphthol aralkyl-type epoxy resin, a dicyclopentadiene-type epoxy resin, a phosphorus-containing epoxy resin, or an oxazolidone ring-containing epoxy resin other than those of the present invention.

[0051] In general formula (8), R ７ are independently a hydrocarbon group having 1 to 10 carbon atoms, for example, an alkyl group such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a t-butyl group, an n-hexyl group, or a cyclohexyl group, and may be the same or different from each other. X is a divalent organic group, for example, an alkylene group such as a methylene group, an ethylene group, an isopropylidene group, an isobutylene group, or a hexafluoroisopropylidene group, -CO-, -O-, -S-, or -SO ２ -, -S-S-, or an aralkylene group represented by formula (8a). In formula (8a), R ８ are independently a hydrogen atom or a hydrocarbon group having 1 or more carbon atoms, for example, a methyl group, and may be the same or different from each other. Ar is a benzene ring or a naphthalene ring, and these benzene rings or naphthalene rings may have, as a substituent, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an aryl group having 6 to 11 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, an aryloxy group having 6 to 11 carbon atoms, or an aralkyloxy group having 7 to 12 carbon atoms.

[0052] As the curing agent, those commonly used as curing agents for epoxy resins, such as various phenolic resins, acid anhydrides, amines, cyanate esters, active esters, hydrazides, acidic polyesters, and aromatic cyanates, can be used. A polyhydroxy resin represented by general formula (6) can also be used, and an active ester resin obtained by esterifying the polyhydroxy resin represented by formula (6) can also be used. These may be used alone or in combination of two or more.

[0053] In the epoxy resin composition of the present invention, the molar ratio of active hydrogen groups in the curing agent per mole of epoxy groups in the total epoxy resin is preferably 0.2 to 1.5 moles, more preferably 0.3 to 1.4 moles, even more preferably 0.5 to 1.3 moles, and particularly preferably 0.8 to 1.2 moles. Outside this range, curing may be incomplete, making it difficult to obtain good cured physical properties. For example, when a phenolic resin-based curing agent or an amine-based curing agent is used, the active hydrogen groups are blended in an approximately equimolar ratio relative to the epoxy groups. When an acid anhydride-based curing agent is used, 0.5 to 1.2 moles, preferably 0.6 to 1.0 moles, of acid anhydride groups are blended per mole of epoxy groups. When the phenolic resin of the present invention is used alone as a curing agent, it is desirable to use a range of 0.9 to 1.1 moles per mole of epoxy resin.

[0054] The active hydrogen group in the present invention refers to a functional group having active hydrogen reactive with an epoxy group (including a functional group having latent active hydrogen that generates active hydrogen by hydrolysis or the like, and a functional group that exhibits an equivalent curing action), and specific examples thereof include an acid anhydride group, a carboxyl group, an amino group, and a phenolic hydroxyl group. Note that, with regard to the active hydrogen group, 1 mole of a carboxyl group or a phenolic hydroxyl group is 1 mole of an amino group (NH ２ ) is calculated as 2 moles. Also, if the active hydrogen group is unclear, the active hydrogen equivalent can be determined by measurement. For example, the active hydrogen equivalent of the curing agent used can be determined by reacting a monoepoxy resin such as phenyl glycidyl ether, whose epoxy equivalent is known, with a curing agent, whose active hydrogen equivalent is unknown, and measuring the amount of monoepoxy resin consumed.

[0055] Specific examples of the phenolic resin curing agent that can be used in the epoxy resin composition of the present invention include bisphenol A, bisphenol F, bisphenol C, bisphenol K, bisphenol Z, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol S, tetramethylbisphenol Z, tetrabromobisphenol A, dihydroxydiphenyl sulfide, 4,Bisphenols such as 4'-thiobis(3-methyl-6-t-butylphenol), dihydroxybenzenes such as catechol, resorcinol, methylresorcinol, hydroquinone, monomethylhydroquinone, dimethylhydroquinone, trimethylhydroquinone, mono-t-butylhydroquinone, and di-t-butylhydroquinone, and hydroxynaphthalenes such as dihydroxynaphthalene, dihydroxymethylnaphthalene, dihydroxymethylnaphthalene, and trihydroxynaphthalene. phosphorus-containing phenolic hardeners such as LC-950PM60 (manufactured by Shin-AT&C Co., Ltd.), phenolic novolac resins such as Shounol BRG-555 (manufactured by Aica Kogyo Co., Ltd.), cresol novolac resins such as DC-5 (manufactured by Nippon Steel Chemical & Material Co., Ltd.), triazine skeleton-containing phenolic resins, aromatic modified phenolic novolac resins, bisphenol A novolac resins, trishydroxyphenylmethane novolac resins such as Resitop TPM-100 (manufactured by Gun-ei Chemical Industry Co., Ltd.), phenol compounds such as phenols such as naphthol novolak resins, condensates of naphthols and / or bisphenols with aldehydes, phenols such as SN-160, SN-395, and SN-485 (manufactured by Nippon Steel Chemical & Material Co., Ltd.), condensates of phenols and / or naphthols and / or bisphenols with xylylene glycol, condensates of phenols and / or naphthols and isopropenylacetophenone, reaction products of phenols and / or naphthols and / or bisphenols with dicyclopentadiene, reaction products of phenols and / or naphthols and / or bisphenols with divinylbenzene, reaction products of phenols and / or naphthols and / or bisphenols with terpenes, condensates of phenols and / or naphthols and / or bisphenols with biphenyl-based crosslinking agents, polybutadiene-modified phenolic resins, and phenolic resins having a spiro ring. From the viewpoint of availability, phenol novolac resin, dicyclopentadiene phenol resin, trishydroxyphenylmethane type novolac resin, aromatic modified phenol novolac resin, etc. are preferred.

[0056] Novolac phenolic resins can be obtained from phenols and crosslinking agents. Examples of phenols include phenol, cresol, xylenol, butylphenol, amylphenol, nonylphenol, butylmethylphenol, trimethylphenol, and phenylphenol. Examples of naphthols include 1-naphthol and 2-naphthol. Other examples include the bisphenols listed above as the phenolic resin curing agents. Examples of aldehydes as crosslinking agents include formaldehyde, acetaldehyde, propylaldehyde, butyraldehyde, valeraldehyde, capronaldehyde, benzaldehyde, chloraldehyde, bromaldehyde, glyoxal, malonaldehyde, succinaldehyde, glutaraldehyde, adipic aldehyde, pimelic aldehyde, sebacic aldehyde, acrolein, crotonaldehyde, salicylaldehyde, phthalaldehyde, hydroxybenzaldehyde, etc. Examples of biphenyl-based crosslinking agents include bis(methylol)biphenyl, bis(methoxymethyl)biphenyl, bis(ethoxymethyl)biphenyl, bis(chloromethyl)biphenyl, etc.

[0057] Specific examples of acid anhydride curing agents include maleic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, methylbicyclo[2.2.1]heptane-2,3-dicarboxylic anhydride, bicyclo[2.2.1]heptane-2,3-dicarboxylic anhydride, 1,2,3,6-tetrahydrophthalic anhydride, pyromellitic anhydride, phthalic anhydride, trimellitic anhydride, methylnadic acid, copolymers of styrene monomer and maleic anhydride, and copolymers of indenes and maleic anhydride.

[0058] Specific examples of the amine-based curing agent include aromatic amines such as diethylenetriamine, triethylenetetramine, metaxylenediamine, isophoronediamine, diaminodiphenylmethane, diaminodiphenylsulfone, diaminodiphenylether, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, polyetheramine, biguanide compounds, dicyandiamide, and anisidine, and amine-based compounds such as polyamidoamines, which are condensates of polyamines with acids such as dimer acid.

[0059] The cyanate ester compound is not particularly limited as long as it is a compound having two or more cyanate groups (cyanate ester groups) in one molecule. Examples thereof include novolac-type cyanate ester curing agents such as phenol novolac-type and alkylphenol novolac-type, naphthol aralkyl-type cyanate ester curing agents, biphenyl alkyl-type cyanate ester curing agents, dicyclopentadiene-type cyanate ester curing agents, bisphenol-type cyanate ester curing agents such as bisphenol A-type, bisphenol F-type, bisphenol E-type, tetramethylbisphenol F-type, and bisphenol S-type, and prepolymers of these partially converted to triazine. Specific examples of cyanate ester-based curing agents include bisphenol A dicyanate, polyphenol cyanate (oligo(3-methylene-1,5-phenylene cyanate), bis(3-methyl-4-cyanate phenyl)methane, bis(3-ethyl-4-cyanate phenyl)methane, bis(4-cyanate phenyl)-1,1-ethane, 4,4-dicyanate-diphenyl, 2,2-bis(4-cyanate phenyl)-1,1,1,3,3,3-hexafluoropropane, 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4'-ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanate phenyl) Examples of suitable cyanate resins include bifunctional cyanate resins such as bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanatephenyl-1-(methylethylidene))benzene, bis(4-cyanatephenyl)thioether, and bis(4-cyanatephenyl)ether; cyanate esters of trihydric phenols such as tris(4-cyanatephenyl)-1,1,1-ethane and bis(3,5-dimethyl-4-cyanatephenyl)-4-cyanatephenyl-1,1,1-ethane; polyfunctional cyanate resins derived from phenol novolak, cresol novolak, and phenolic resins containing a dicyclopentadiene structure; and prepolymers in which these cyanate resins are partially converted to triazine. These may be used alone or in combination.

[0060] The active ester curing agent is not particularly limited, but compounds having two or more highly reactive ester groups per molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds, are generally preferred. The active ester curing agent is preferably one obtained by a condensation reaction between a carboxylic acid compound and / or a thiocarboxylic acid compound and a hydroxy compound and / or a thiol compound. From the viewpoint of improving heat resistance in particular, active ester curing agents obtained from a carboxylic acid compound and a hydroxy compound are preferred, and active ester curing agents obtained from a carboxylic acid compound and a phenol compound and / or a naphthol compound are more preferred. Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. Examples of phenol compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalene, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucinol, benzenetriol, dicyclopentadienyl diphenol, dicyclopentadiene phenol resin, which is a raw material for the epoxy resin of the present invention, and phenol novolak. Active ester curing agents can be used singly or in combination. Specific examples of the active ester curing agent include active ester curing agents containing a dicyclopentadienyldiphenol structure, active ester curing agents containing a naphthalene structure, active ester curing agents which are acetylated phenol novolac, and active ester curing agents which are benzoylated phenol novolac. Of these, active ester curing agents containing a dicyclopentadienyldiphenol structure, which is a raw material for the epoxy resin of the present invention, are more preferred because of their excellent ability to improve peel strength.

[0061] Specific examples of other curing agents include phosphine compounds such as triphenylphosphine, phosphonium salts such as tetraphenylphosphonium bromide, imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, and 1-cyanoethyl-2-methylimidazole, imidazole salts which are salts of imidazoles with trimellitic acid, isocyanuric acid, boron, or the like, quaternary ammonium salts such as trimethylammonium chloride, diazabicyclo compounds, salts of diazabicyclo compounds with phenols, phenol novolac resins, or the like, complex compounds of boron trifluoride with amines, ether compounds, or the like, aromatic phosphonium, or iodonium salts.

[0062] A curing accelerator can be used in the epoxy resin composition as needed. Examples of curing accelerators that can be used include imidazoles such as 2-methylimidazole, 2-ethylimidazole, and 2-ethyl-4-methylimidazole; tertiary amines such as 4-dimethylaminopyridine, 2-(dimethylaminomethyl)phenol, and 1,8-diaza-bicyclo(5,4,0)undecene-7; phosphines such as triphenylphosphine, tricyclohexylphosphine, and triphenylphosphinetriphenylborane; and metal compounds such as tin octoate. When a curing accelerator is used, the amount used is preferably 0.02 to 5 parts by mass per 100 parts by mass of the epoxy resin component in the epoxy resin composition of the present invention. The use of a curing accelerator can lower the curing temperature and shorten the curing time.

[0063] The epoxy resin composition may contain an organic solvent or a reactive diluent for adjusting viscosity.

[0064] Examples of organic solvents include amides such as N,N-dimethylformamide and N,N-dimethylacetamide, ethers such as ethylene glycol monomethyl ether, dimethoxydiethylene glycol, ethylene glycol diethyl ether, diethylene glycol diethyl ether and triethylene glycol dimethyl ether, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, alcohols such as methanol, ethanol, 1-methoxy-2-propanol, 2-ethyl-1-hexanol, benzyl alcohol, ethylene glycol, propylene glycol, butyl diglycol and pine oil, and vinegar. Examples of suitable solvents include acetate esters such as butyl acetate, methoxybutyl acetate, methyl cellosolve acetate, cellosolve acetate, ethyl diglycol acetate, propylene glycol monomethyl ether acetate, carbitol acetate, and benzyl alcohol acetate; benzoate esters such as methyl benzoate and ethyl benzoate; cellosolves such as methyl cellosolve, cellosolve, and butyl cellosolve; carbitols such as methyl carbitol, carbitol, and butyl carbitol; aromatic hydrocarbons such as benzene, toluene, and xylene; dimethyl sulfoxide, acetonitrile, and N-methylpyrrolidone, but are not limited to these.

[0065] Examples of reactive diluents include monofunctional glycidyl ethers such as allyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and tolyl glycidyl ether, and monofunctional glycidyl esters such as neodecanoic acid glycidyl ester, but are not limited to these.

[0066] These organic solvents or reactive diluents are preferably used alone or in combination in a resin composition in an amount of 90% by mass or less as nonvolatile matter, with the appropriate type and amount being selected appropriately depending on the application. For example, for printed wiring board applications, polar solvents with a boiling point of 160°C or less, such as methyl ethyl ketone, acetone, and 1-methoxy-2-propanol, are preferred, with the amount used in the resin composition being preferably 40 to 80% by mass as nonvolatile matter. For adhesive film applications, for example, ketones, acetate esters, carbitols, aromatic hydrocarbons, dimethylformamide, dimethylacetamide, and N-methylpyrrolidone are preferred, with the amount used being preferably 30 to 60% by mass as nonvolatile matter.

[0067] The epoxy resin composition may contain other thermosetting resins or thermoplastic resins to the extent that the properties are not impaired. Examples of such resins include, but are not limited to, phenolic resins, benzoxazine resins, bismaleimide resins, bismaleimide triazine resins, acrylic resins, petroleum resins, indene resins, coumarone-indene resins, phenoxy resins, polyurethane resins, polyester resins, polyamide resins, polyimide resins, polyamideimide resins, polyetherimide resins, polyphenylene ether resins, modified polyphenylene ether resins, polyethersulfone resins, polysulfone resins, polyetheretherketone resins, polyphenylene sulfide resins, polyvinyl formal resins, polysiloxane compounds, and reactive functional group-containing alkylene resins such as hydroxyl group-containing polybutadienes.

[0068] Various known flame retardants can be used in the epoxy resin composition to improve the flame retardancy of the resulting cured product. Usable flame retardants include, for example, halogen-based flame retardants, phosphorus-based flame retardants, nitrogen-based flame retardants, silicone-based flame retardants, inorganic flame retardants, and organic metal salt-based flame retardants. From an environmental perspective, halogen-free flame retardants are preferred, and phosphorus-based flame retardants are particularly preferred. These flame retardants may be used alone or in combination of two or more.

[0069] The phosphorus-based flame retardant may be either an inorganic phosphorus-based compound or an organic phosphorus-based compound, such as red phosphorus, ammonium phosphates such as monoammonium phosphate, diammonium phosphate, triammonium phosphate, and ammonium polyphosphate, or inorganic nitrogen-containing phosphorus compounds such as phosphoric acid amide. Examples of the organic phosphorus compounds include general-purpose organic phosphorus compounds such as aliphatic phosphoric acid esters, phosphoric acid ester compounds, for example, condensed phosphoric acid esters such as PX-200 (manufactured by Daihachi Chemical Industry Co., Ltd.), phosphazenes, phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphorane compounds, and organic nitrogen-containing phosphorus compounds; metal salts of phosphinic acid; and cyclic organic phosphorus compounds such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, and 10-(2,7-dihydroxynaphthyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide; and phosphorus-containing epoxy resins and phosphorus-containing curing agents, which are derivatives of these compounds obtained by reacting them with compounds such as epoxy resins and phenolic resins.

[0070] The amount of flame retardant to be added is appropriately selected depending on the type of phosphorus-based flame retardant, the components of the epoxy resin composition, and the desired level of flame retardancy. For example, the phosphorus content in the organic components (excluding organic solvents) of the epoxy resin composition is preferably 0.2 to 4 mass%, more preferably 0.4 to 3.5 mass%, and even more preferably 0.6 to 3 mass%. If the phosphorus content is too low, it may be difficult to ensure flame retardancy, while if it is too high, it may have a negative impact on heat resistance. Furthermore, when a phosphorus-based flame retardant is used, a flame retardant aid such as magnesium hydroxide may be used in combination.

[0071] Fillers can be used in epoxy resin compositions as needed. Specific examples include fused silica, crystalline silica, alumina, silicon nitride, aluminum hydroxide, boehmite, magnesium hydroxide, talc, mica, calcium carbonate, calcium silicate, calcium hydroxide, magnesium carbonate, barium carbonate, barium sulfate, boron nitride, carbon, carbon fiber, glass fiber, alumina fiber, silica-alumina fiber, silicon carbide fiber, polyester fiber, cellulose fiber, aramid fiber, ceramic fiber, fine rubber particles, silicone rubber, thermoplastic elastomer, carbon black, and pigments. A common reason for using fillers is to improve impact resistance. Furthermore, metal hydroxides such as aluminum hydroxide, boehmite, and magnesium hydroxide function as flame retardant aids, improving flame retardancy. The amount of these fillers added is preferably 1 to 150% by mass, more preferably 10 to 70% by mass, of the total epoxy resin composition. Higher amounts may result in reduced adhesion, which is necessary for laminate applications, and may also result in brittle cured products, which may not achieve sufficient mechanical properties. If the blending amount is too small, the effects of blending the filler, such as improving the impact resistance of the cured product, may not be achieved.

[0072] When the epoxy resin composition is used to form a plate-shaped substrate or the like, a fibrous filler is preferred in terms of dimensional stability, bending strength, etc. A glass fiber substrate in which glass fibers are woven in a mesh pattern is more preferred.

[0073] The epoxy resin composition may further contain various additives, such as a silane coupling agent, an antioxidant, a mold release agent, an antifoaming agent, an emulsifier, a thixotropic agent, a smoothing agent, a flame retardant, a pigment, etc. The amount of these additives to be added is preferably in the range of 0.01 to 20% by mass based on the epoxy resin composition.

[0074] The epoxy resin composition can be impregnated into a fibrous substrate to produce a prepreg for use in printed wiring boards, etc. The fibrous substrate can be, but is not limited to, inorganic fibers such as glass, or woven or nonwoven fabrics of organic fibers such as polyester resin, polyamine resin, polyacrylic resin, polyimide resin, or aromatic polyamide resin. The method for producing a prepreg from the epoxy resin composition is not particularly limited. For example, the epoxy resin composition can be immersed in a resin varnish prepared by adjusting the viscosity with an organic solvent, and then heated and dried to semi-cure (B-stage) the resin component. For example, the prepreg can be obtained by heating and drying at 100 to 200°C for 1 to 40 minutes. The resin content in the prepreg is preferably 30 to 80% by mass.

[0075] Furthermore, prepreg curing can be achieved using methods commonly used for curing laminates in the manufacture of printed wiring boards, but is not limited thereto. For example, when forming a laminate using prepreg, one or more prepregs are laminated together, with metal foil placed on one or both sides to form a laminate, and the laminate is then heated and pressurized to form an integrated laminate. The metal foil can be a single, alloy, or composite metal foil of copper, aluminum, brass, nickel, or the like. The prepreg is then cured by heating and pressurizing the resulting laminate to obtain a laminate. A heating temperature of 160 to 220°C, a pressurizing pressure of 5 to 50 MPa, and a heating and pressurizing time of 40 to 240 minutes are preferred to obtain the desired cured product. A low heating temperature may result in insufficient progress of the curing reaction, while a high temperature may initiate decomposition of the epoxy resin composition. Furthermore, a low pressurizing pressure may result in air bubbles remaining inside the resulting laminate, potentially reducing electrical properties, while a high pressurizing pressure may cause the resin to flow before curing, potentially preventing the desired cured product thickness from being obtained. Furthermore, if the heating and pressurizing time is too short, the curing reaction may not proceed sufficiently, whereas if it is too long, thermal decomposition of the epoxy resin composition in the prepreg may occur, which is undesirable.

[0076] The epoxy resin composition can be cured to obtain a cured epoxy resin product by the same method as for known epoxy resin compositions. The same methods as for known epoxy resin compositions can be used to obtain a cured product, and suitable methods include casting, injection, potting, dipping, drip coating, transfer molding, compression molding, etc., or laminating the composition in the form of a resin sheet, resin-coated copper foil, prepreg, etc., and curing it under heat and pressure to form a laminate. The curing temperature is typically 100 to 300°C, and the curing time is typically about 1 to 5 hours.

[0077] The epoxy resin cured product of the present invention can be in the form of a laminate, a molded product, an adhesive product, a coating film, a film, or the like.

[0078] An epoxy resin composition was prepared, and laminates and cured products were evaluated after heat curing. As a result, it was possible to provide an epoxy curable resin composition that exhibits excellent low dielectric properties in the cured product. Specifically, the dielectric properties can be expressed as a relative dielectric constant of 3.20 or less, more preferably 3.10 or less, and even more preferably 3.00 or less, and a dielectric dissipation factor of 0.025 or less, more preferably 0.022 or less, and even more preferably 0.020 or less.

[0079] The present invention will be specifically explained using examples and comparative examples, but the present invention is not limited to these. Unless otherwise specified, "parts" represents parts by mass, "%" represents mass %, and "ppm" represents mass ppm. In addition, the measurement methods were as follows.

[0080] (1) Hydroxyl equivalent: Measured in accordance with JIS K0070, expressed in units of g / eq. Unless otherwise specified, the hydroxyl equivalent of a phenolic resin refers to the phenolic hydroxyl equivalent.

[0081] (2) Epoxy equivalent: Measurement was performed in accordance with JIS K7236 standard, and the unit was expressed as "g / eq." Specifically, an automatic potentiometric titrator (COM-1600ST, manufactured by Hiranuma Sangyo Co., Ltd.) was used, and chloroform was used as a solvent. A tetraethylammonium bromide acetate solution was added, and titration was performed with a 0.1 mol / L perchloric acid-acetic acid solution.

[0082] (3) Melt Viscosity: The viscosity was measured at 150° C. using an ICI viscosity measuring device (CV-1S, manufactured by Toa Kogyo Co., Ltd.).

[0083] (4) Dielectric constant and dielectric loss tangent: Measured in accordance with IPC-TM-650 2.5.5.9. Specifically, the sample was dried in an oven set at 105°C for 2 hours, allowed to cool in a desiccator, and then evaluated by determining the dielectric constant and dielectric loss tangent at a frequency of 1 GHz by the capacitance method using a material analyzer manufactured by AGILENT Technologies.

[0084] (5) GPC (gel permeation chromatography) measurement: A main body (Tosoh Corporation, HLC-8220GPC) equipped with columns (Tosoh Corporation, TSKgel G4000HXL, TSKgel G3000HXL, TSKgel G2000HXL) in series was used, and the column temperature was set to 40 ° C. Tetrahydrofuran (THF) was used as the eluent, with a flow rate of 1 mL / min, and a differential refractive index detector was used as the detector. 0.1 g of sample was dissolved in 10 mL of THF and filtered through a microfilter, and 50 μL of the solution was used as the measurement sample. Data processing was performed using Tosoh Corporation's GPC-8020 Model II Version 6.00.

[0085] (6) IR: Using a Fourier transform infrared spectrophotometer (Spectrum One FT-IR Spectrometer 1760X, manufactured by Perkin Elmer Precisly), a sample dissolved in toluene was applied to the ATR using a diamond ATR, dried, and then measured at a wave number of 650 to 4000 cm. －１ The absorbance was measured.

[0086] The abbreviations used in the examples and comparative examples are as follows.

[0087] [Epoxy resins] E1: Epoxy resin obtained in Example 1 E2: Epoxy resin obtained in Example 2 E3: Epoxy resin obtained in Example 3 E4: Epoxy resin obtained in Example 4 E5: Epoxy resin obtained in Example 5 E6: Epoxy resin obtained in Example 6 E7: Epoxy resin obtained in Example 7 E8: Epoxy resin obtained in Example 8 E9: Epoxy resin obtained in Example 9 E10: Epoxy resin obtained in Example 10 E11: Epoxy resin obtained in Example 11 EH1: Epoxy resin obtained in Comparative Example 1 EH2: Epoxy resin obtained in Comparative Example 2 EH3: Epoxidized product of a mixture of 20 parts of bisphenol F (P2 below) and 80 parts of TCD phenol (PH1 below) described in Comparative Example 3 (an epoxy resin corresponding to the epoxy resin EP4 described in Example 4 of Japanese Patent No. 5299976) EH4: Epoxidized product of a mixture of 30 parts of bisphenol F (P2 below) and 70 parts of TCD phenol (PH1 below) described in Comparative Example 4 (an epoxy resin corresponding to the epoxy resin EP5 described in Example 5 of Japanese Patent No. 5299976) EH5: Epoxy resin obtained in Comparative Example 5

[0088] [Epoxy resin raw materials] P1: phenolic resin obtained in Synthesis Example 1 P2: bisphenol F (hydroxyl equivalent 100) P3: bisphenol A (hydroxyl equivalent 114) P4: bisphenol C (hydroxyl equivalent 128) P5: bisphenol M (hydroxyl equivalent 173) P6: bisphenol P (hydroxyl equivalent 173) P7: tetramethylbisphenol F (hydroxyl equivalent 128) P8: tetramethylbisphenol A (hydroxyl equivalent 142) P9: 3,3',5,5'-tetramethylbiphenyl-4,4'-diol (hydroxyl equivalent 121) P10: t-butylcatechol (hydroxyl equivalent 83) PH1: TCD phenol (DPP-6115H manufactured by Nippon Oil Corporation, hydroxyl equivalent 182)

[0089] [Curing agent] P1: phenolic resin obtained in Synthesis Example 1 P11: phenolic novolak resin (manufactured by Aica Kogyo Co., Ltd., Shounol BRG-557, hydroxyl group equivalent: 105)

[0090] [Curing accelerator] C1: 2E4MZ: 2-ethyl-4-methylimidazole (Curesol 2E4MZ, manufactured by Shikoku Chemicals Corporation)

[0091] Synthesis Example 1 Into a reaction apparatus consisting of a separable glass flask equipped with a stirrer, a thermometer, a nitrogen inlet tube, a dropping funnel, and a condenser, 140 parts of 2,6-xylenol (structural formula below), 47% BF ３ 9.3 parts of the ether complex was charged and heated with stirring to 100° C. While maintaining the temperature, 154.6 parts of dicyclopentadiene (structural formula below) was added dropwise over 1 hour. The reaction was continued for another 4 hours at 115-125°C, and 11 parts of calcium hydroxide were added. 19 parts of a 10% aqueous oxalic acid solution were then added. The mixture was then heated to 160°C for dehydration, and then heated to 200°C under a reduced pressure of 5 mmHg to remove unreacted raw materials by evaporation. 1,320 parts of MIBK were added to dissolve the product, and 400 parts of 80°C hot water was added for water washing, and the lower layer of water was separated and removed. The mixture was then heated to 160°C under a reduced pressure of 5 mmHg to remove the MIBK by evaporation, yielding a reddish-brown phenolic resin (P1, structural formula below). The hydroxyl equivalent was 288, Mw was 287, and Mn was 243.

[0092] Here, R ２２ independently represent a hydrogen atom or a group represented by formula (6a) or formula (6b), and at least one of them is formula (6a) or formula (6b).

[0093] Example 1 A reaction apparatus equipped with a stirrer, a thermometer, a nitrogen inlet tube, a dropping funnel, and a condenser was charged with 78 parts of the phenol resin (P1) obtained in Synthesis Example 1, 13 parts of bisphenol F, 185 parts of epichlorohydrin (structural formula below), 55 parts of diethylene glycol dimethyl ether was added and heated to 65°C. While maintaining the temperature at 63-67°C under a reduced pressure of 125 mmHg, 35.9 parts of a 49% aqueous sodium hydroxide solution was added dropwise over 4 hours. During this time, epichlorohydrin was azeotroped with water, and the resulting water was gradually removed from the system. After completion of the reaction, epichlorohydrin was recovered under conditions of 5 mmHg and 180°C, and 290 parts of MIBK was added to dissolve the product. Subsequently, 90 parts of water was added to dissolve the by-product sodium chloride, and the mixture was allowed to stand, allowing the lower layer of saline to separate and remove. After neutralization with an aqueous phosphoric acid solution, the resin solution was washed with water until the washings were neutral and then filtered. The mixture was heated to 180°C under a reduced pressure of 5 mmHg, and the MIBK was distilled off, yielding a reddish-brown epoxy resin (E1). The epoxy equivalent is 254, the melt viscosity is 0.005 Pa·s, the Mw is 345, the Mn is 277, and the absorption ratio (A ３０４０ / A １２１０ ) was 0.14. The GPC and IR spectra of the obtained epoxy resin (E1) are shown in Figure 1 and Figure 2, respectively. In Figure 1, peak (a) corresponds to the epoxy resin component (B) represented by general formula (5a) or (5b), and peak (b) corresponds to the epoxidized product of the polyhydric hydroxy resin represented by general formula (6) in which m3 is 0 (zero) (m3 = 0 form), which, like peak (a), corresponds to the epoxy resin component (B). The combined GPC area % of these peaks was 80%.

[0094] Example 2 A reddish-brown epoxy resin (E2) was obtained by the same procedure as in Example 1, except that the amount of phenolic resin (P1) was changed to 58 parts and the amount of bisphenol F was changed to 20 parts. The epoxy equivalent was 224, the melt viscosity was 0.004 Pa s, Mw was 350, and Mn was 285. The GPC area % of the epoxy resin component (B), which is the sum of the epoxy resin component represented by general formula (5a) or (5b) and the epoxidized product of the polyhydric hydroxy resin represented by general formula (6) in which m3 is 0 (zero) (m3 = 0 form), was 80%.

[0095] Example 3: The same procedure as in Example 1 was carried out, except that the amount of phenolic resin (P1) was changed to 38 parts and the amount of bisphenol F was changed to 27 parts, to obtain a reddish-brown epoxy resin (E3). The epoxy equivalent was 199, the melt viscosity was 0.003 Pa s, Mw was 362, and Mn was 295. The GPC area % of epoxy resin component (B), which is the sum of the epoxy resin component represented by general formula (5a) or (5b) and the epoxidized product of the polyhydric hydroxy resin represented by general formula (6) in which m3 is 0 (zero) (m3 = 0 form), was 81%.

[0096] Example 4 A reddish-brown epoxy resin (E4) was obtained by the same procedure as in Example 1, except that the amount of phenolic resin (P1) was 58 parts and bisphenol A was 23 parts instead of bisphenol F. The epoxy equivalent was 228, the melt viscosity was 0.004 Pa s, Mw was 349, and Mn was 286. The GPC area % of epoxy resin component (B), which is the sum of the epoxy resin component represented by general formula (5a) or (5b) and the epoxidized product of the polyhydric hydroxy resin represented by general formula (6) in which m3 is 0 (zero) (m3 = 0 form), was 77%.

[0097] Example 5: The same procedure as in Example 1 was repeated, except that the amount of phenolic resin (P1) was 58 parts and bisphenol C was 26 parts instead of bisphenol F, to obtain a reddish-brown epoxy resin (E5). The epoxy equivalent was 237, the melt viscosity was 0.004 Pa s, Mw was 354, and Mn was 288. The GPC area % of epoxy resin component (B), which is the sum of the epoxy resin component represented by general formula (5a) or (5b) and the epoxidized product of the polyhydric hydroxy resin represented by general formula (6) in which m3 is 0 (zero) (m3 = 0 form), was 64%.

[0098] Example 6 A reddish-brown epoxy resin (E6) was obtained by the same procedure as in Example 1, except that the phenolic resin (P1) was 58 parts and bisphenol M was used instead of bisphenol F at 35 parts. The epoxy equivalent was 267, the melt viscosity was 0.008 Pa s, Mw was 344, and Mn was 277. The GPC area % of the epoxy resin component (B), which is the sum of the epoxy resin component represented by general formula (5a) or (5b) and the epoxidized product of the polyhydric hydroxy resin represented by general formula (6) in which m3 is 0 (zero) (m3 = 0 form), was 73%.

[0099] Example 7 A reddish-brown epoxy resin (E7) was obtained by the same procedure as in Example 1, except that the amount of phenolic resin (P1) was 58 parts and bisphenol P was 35 parts instead of bisphenol F. The epoxy equivalent was 267, the melt viscosity was 0.008 Pa s, Mw was 344, and Mn was 277. The GPC area % of epoxy resin component (B), which is the sum of the epoxy resin component represented by general formula (5a) or (5b) and the epoxidized products of the polyhydric hydroxy resin represented by general formula (6) in which m3 is 0 (zero) (m3 = 0 form), was 73%.

[0100] Example 8: A reddish-brown epoxy resin (E8) was obtained by the same procedure as in Example 1, except that the phenolic resin (P1) was 58 parts and tetramethylbisphenol F was 26 parts instead of bisphenol F. The epoxy equivalent was 237, the melt viscosity was 0.005 Pa s, Mw was 354, and Mn was 288. The GPC area % of the epoxy resin component (B), which is the sum of the epoxy resin component represented by general formula (5a) or (5b) and the epoxidized product of the polyhydric hydroxy resin represented by general formula (6) in which m3 is 0 (zero) (m3 = 0 form), was 64%.

[0101] Example 9: A reddish-brown epoxy resin (E9) was obtained by the same procedure as in Example 1, except that the phenolic resin (P1) was 58 parts and tetramethylbisphenol A was used instead of bisphenol F (28 parts). The epoxy equivalent was 247, the melt viscosity was 0.005 Pa s, Mw was 345, and Mn was 278. The GPC area % of epoxy resin component (B), which is the sum of the epoxy resin component represented by general formula (5a) or (5b) and the epoxidized products of the polyhydric hydroxy resin represented by general formula (6) in which m3 is 0 (zero) (m3 = 0 form), was 66%.

[0102] Example 10: A reddish-brown epoxy resin (E10) was obtained by the same procedure as in Example 1, except that the phenolic resin (P1) was 58 parts and bisphenol F was replaced with 24 parts of 3,3',5,5'-tetramethylbiphenyl-4,4'-diol. The epoxy equivalent was 233, the melt viscosity was 0.005 Pa s, the Mw was 350, and the Mn was 282. The GPC area percentage of the epoxy resin component (B), which is the sum of the epoxy resin component represented by general formula (5a) or (5b) and the epoxidized product of the polyhydric hydroxy resin represented by general formula (6) in which m3 is 0 (zero) (m3 = 0 form), was 62%.

[0103] Example 11 A reddish-brown epoxy resin (E11) was obtained by the same procedure as in Example 1, except that the phenolic resin (P1) was 58 parts and t-butylcatechol was used instead of bisphenol F (17 parts). The epoxy equivalent was 207, the melt viscosity was 0.003 Pa s, Mw was 348, and Mn was 280. The GPC area % of the epoxy resin component (B), which is the sum of the epoxy resin component represented by general formula (5a) or (5b) and the epoxidized products of the polyhydric hydroxy resin represented by general formula (6) in which m3 is 0 (zero) (m3 = 0 form), was 55%.

[0104] Comparative Example 1 A reddish-brown epoxy resin (EH1) was obtained by the same procedure as in Example 1, except that 115 parts of phenolic resin (P1) was used and no bisphenol F (0 part) was added. The epoxy equivalent was 344, the melt viscosity was 0.6 Pa s, Mw was 470, and Mn was 440. The GPC area percentage of the epoxy resin component (B) in which m3 was 0 (zero) (m3 = 0 form), among the epoxidized products of the polyhydric hydroxy resin represented by general formula (6), was 5%.

[0105] Comparative Example 2: The same procedure as in Example 1 was carried out, except that the phenolic resin (P1) was not added (0 part) and bisphenol F was used (40 parts), to obtain a colorless and transparent epoxy resin (EH2). The epoxy equivalent was 156, the melt viscosity was 0.003 Pa s, the Mw was 352, and the Mn was 313. The GPC area percentage of the epoxy resin component (B) represented by general formula (5a) or (5b) was 84%.

[0106] Comparative Example 3 A flask equipped with a stirrer, reflux condenser, and stirrer was purged with nitrogen while adding 31 parts of bisphenol F, 229 parts of TCD phenol (DPP-6115H manufactured by Nippon Oil Corporation, hydroxyl equivalent 182 g / eq.) (such that after completion of the reaction, the mass ratio of bisphenol F epoxy resin to TCD phenol epoxy resin was 20:80), 846 parts of epichlorohydrin, and 250 parts of dimethyl sulfoxide, which were dissolved under stirring and heated to 45 ° C. Next, 76 parts of flaky sodium hydroxide were added in portions over 90 minutes, and the reaction was continued for another 3 hours at 45 ° C. and 1 hour at 70 ° C. After completion of the reaction, the mixture was washed with 280 parts of water, and the oil layer was distilled off under reduced pressure at 140 ° C. to remove excess solvents such as epichlorohydrin. 800 parts of methyl isobutyl ketone was added to the residue and dissolved, and the temperature was raised to 70 ° C. While stirring, 20 parts of a 30 wt% aqueous solution of sodium hydroxide was added, and the mixture was allowed to react for 1 hour. After that, the oil layer was washed with water until the wash water became neutral, and the resulting solution was distilled off methyl isobutyl ketone and the like under reduced pressure at 160°C using a rotary evaporator to obtain 300 parts of a liquid epoxy resin (EH3) of the present invention. The resulting epoxy resin had an epoxy equivalent of 235 g / eq., a softening point of 56°C, and a melt viscosity at 150°C of 0.08 Pa s.

[0107] Comparative Example 4 A flask equipped with a stirrer, reflux condenser, and stirring device was purged with nitrogen, and 54 parts of bisphenol F, 229 parts of TCD phenol (DPP-6115H manufactured by Nippon Oil Corporation, hydroxyl equivalent 182 g / eq.) (such that after completion of the reaction, the mass ratio of bisphenol F type epoxy resin to TCD phenol epoxy resin was 30:70), 968 parts of epichlorohydrin, and 250 parts of dimethyl sulfoxide were added, dissolved under stirring, and heated to 45 ° C. Next, 76 parts of flaky sodium hydroxide were added in portions over 90 minutes, and then the reaction was continued for another 3 hours at 45 ° C. and 1 hour at 70 ° C. After completion of the reaction, the mixture was washed with 280 parts of water, and the oil layer was distilled off under reduced pressure at 140 ° C. to remove excess solvents such as epichlorohydrin. 800 parts of methyl isobutyl ketone was added to the residue and dissolved, and the temperature was raised to 70 ° C. While stirring, 20 parts of a 30 wt% aqueous solution of sodium hydroxide was added, and the mixture was allowed to react for 1 hour. After that, the oil layer was washed with water until the wash water became neutral, and methyl isobutyl ketone and the like were distilled off from the resulting solution using a rotary evaporator at 160°C under reduced pressure to obtain 300 parts of a liquid epoxy resin (EH4) of the present invention. The resulting epoxy resin had an epoxy equivalent of 226 g / eq., a softening point of 51°C, and a melt viscosity at 150°C of 0.05 Pa s.

[0108] Comparative Example 5 A reddish-brown epoxy resin (EH5) was obtained by the same procedure as in Example 1, except that the amount of phenolic resin (P1) was changed to 104 parts and the amount of bisphenol F was changed to 4 parts. The epoxy equivalent was 324, the melt viscosity was 0.5 Pa s, Mw was 440, and Mn was 410. The GPC area % of epoxy resin component (B), which is the sum of the epoxy resin component represented by general formula (5a) or (5b) and the epoxidized products of the polyhydric hydroxy resin represented by general formula (6) in which m3 is 0 (zero) (m3 = 0 form), was 9%.

[0109] The physical properties of the epoxy resins (E1 to E11, EH1 to EH5) are shown in Tables 1 and 2. The GPC area % shown in Tables 1 and 2 indicates the combined GPC area % of the epoxy resin component (B) represented by general formula (5a) or (5b) and the epoxidized products of the polyhydric hydroxy resin represented by general formula (6) in which m3 is 0 (zero) (m3 = 0 form).

[0110]

[0111]

[0112] Example 12: 100 parts of epoxy resin (E1) as the epoxy resin, 41.3 parts of phenolic resin (P11) as the curing agent, and 0.40 parts of C1 as the curing accelerator were blended and dissolved in a mixed solvent prepared from MEK, propylene glycol monomethyl ether, and N,N-dimethylformamide to obtain an epoxy resin composition varnish. The resulting epoxy resin composition varnish was impregnated into glass cloth (WEA 7628 XS13, 0.18 mm thick, manufactured by Nitto Boseki Co., Ltd.). The impregnated glass cloth was dried for 9 minutes in a hot air circulating oven at 150°C to obtain a prepreg. The resulting prepreg was loosened and sieved to obtain a powdery prepreg powder (100 mesh pass). The resulting prepreg powder was placed in a fluororesin mold and vacuum pressed at 2 MPa under the following temperature conditions: 130°C x 15 minutes + 190°C x 80 minutes. A 50 mm square x 2 mm thick test specimen was obtained. The results of the relative dielectric constant and dielectric loss tangent of the test specimens are shown in Table 3.

[0113] Examples 13 to 23 and Comparative Example 6 The ingredients were blended in the amounts (parts) shown in Tables 3 and 4, and the same procedure as in Example 12 was carried out to obtain test pieces. The curing accelerator was used in an amount that could adjust the varnish gel time to about 300 seconds. Tests similar to those in Example 12 were carried out, and the results are shown in Tables 3 and 4.

[0114]

[0115]

Claims

1. An epoxy resin comprising an epoxy resin component (A) represented by the following general formula (1) and an epoxy resin component (B) represented by the following general formula (5a) or (5b), wherein the content of the epoxy resin component (B) is in the range of 10 to 90 area % as measured by gel permeation chromatography: (Here, X independently represents a divalent group containing a group represented by the following formula (2), (3a) or (3b), at least one of which is a group represented by formula (2). Z independently represents a glycidyl group or a group represented by the following formula (4a) or (4b), provided that at least one of Z in formula (1) and formula (2) is a glycidyl group. n represents the number of repetitions, and its average value is a number from 0 to 10.) (where R １ R independently represents a hydrocarbon group having 1 to 10 carbon atoms, i is an integer from 1 to 4, and 4-i and 3-i are both 0 or more. ２ each independently represents a hydrogen atom or a group represented by formula (2a) or formula (2b), and at least one of them is formula (2a) or formula (2b). m1 represents the number of repetitions, and the average value is 0.01 to 5. (where R ３ each independently represents a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a group represented by formula (2a) or formula (2b), and j is 1 to 4 and may be the same or different groups. Y represents a direct bond, an alkylene group which may have a substituent, or an alkylene group which may have an aromatic group. The substituent is a hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom. (where R ３ independently represent a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a group represented by formula (2a) or formula (2b), and q is 1 to 4 and may be the same or different groups. G represents a glycidyl group, and s1 is 0 or 1. Y represents a direct bond, an alkylene group which may have a substituent, or an alkylene group which may have an aromatic group. The substituent is a hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom. (where R ３ independently represent a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a group represented by formula (2a) or formula (2b), and may be the same or different groups. G represents a glycidyl group, s2 is 1 or 2, s3 is an integer of 1 to 5, and s2+s3 is an integer of 2 to 6. Y represents a direct bond, an alkylene group which may have a substituent, or an alkylene group which may have an aromatic group. The substituent is a hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom.

2. The epoxy resin according to claim 1, which has a melt viscosity at 150°C of 0.001 to 0.10 Pa·s.

3. An epoxy resin composition comprising an epoxy resin and a curing agent, characterized in that the epoxy resin according to claim 1 or 2 is an essential component.

4. The epoxy resin composition according to claim 3, wherein the curing agent is a polyhydric hydroxy resin represented by the following general formula (6) or an active ester resin. (where R １ R independently represents a hydrocarbon group having 1 to 10 carbon atoms, i is an integer of 1 to 4, and 4-i and 3-i are both 0 or more. ２１ independently represent a hydrogen atom or a group represented by formula (6a) or formula (6b), and at least one is formula (6a) or formula (6b). m3 represents the number of repetitions, the average value of which is 0 to 5.

5. A prepreg characterized by using the epoxy resin composition according to claim 3.

6. A laminate characterized by using the epoxy resin composition according to claim 3.

7. A printed wiring board characterized by using the epoxy resin composition according to claim 3.

8. A cured product obtained by curing the epoxy resin composition according to claim 3.

9. A method for producing the epoxy resin according to claim 1 or 2, comprising reacting 1 to 20 moles of epihalohydrin with 1 mole of phenolic hydroxyl groups in a mixture obtained by blending 100 parts by mass of a polyhydric hydroxy resin represented by the following general formula (6) with 10 to 300 parts by mass of a phenolic compound represented by the following general formula (7a) or (7b), in the presence of an alkali metal hydroxide. (where R １ R independently represents a hydrocarbon group having 1 to 10 carbon atoms, i is an integer from 1 to 4, and 4-i and 3-i are both 0 or more. ２１ independently represent a hydrogen atom or a group represented by formula (6a) or formula (6b), and at least one is formula (6a) or formula (6b). m3 represents the number of repetitions, the average value of which is 0 to 5. (where R ３ independently represent a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a group represented by formula (2a) or formula (2b), and may be the same or different groups. q1 is 1 or 2, q2 is an integer from 1 to 4, and q1+q2 is an integer from 2 to 6. Y represents a direct bond, an alkylene group which may have a substituent, or an alkylene group which may have an aromatic group. The substituent is a hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom. q3 is 1 or 2, q4 is an integer from 1 to 5, and q3+q4 is an integer from 2 to 6.

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