JP6726053B2 - Epoxy resin composition and cured product thereof - Google Patents

Description

The present invention relates to a resin composition containing an epoxy resin and a curing agent and having high storage stability and high curability, and a cured product or a molded product formed from the composition.

A composition containing an epoxy resin and a curing agent (curable composition) is used in a wide range of fields in order to form a cured product excellent in impact resistance, chemical resistance, water resistance, heat resistance, electrical characteristics, and the like. For example, it is used in adhesives, paints, casting materials, molding materials, laminated plates, electronic materials and the like.

A bisphenol A type epoxy resin is known as a typical epoxy resin. Further, as a curing agent, an amine curing agent, an acid anhydride curing agent, an amide curing agent, a phenol curing agent, etc. are known. However, the bisphenol A type epoxy resin is still insufficient in heat resistance and optical characteristics. Further, in the thermosetting epoxy resin composition, when the curability is increased, the stability is lowered and the pot life is shortened, and when the stability is increased, the curability is lowered. Therefore, it is difficult to achieve both storage stability and pot life and curability. Further, in the thermosetting epoxy resin composition, since the amount of the curing agent used is relatively large, the cured product is affected by the curing agent.

On the other hand, as a curing agent capable of curing an epoxy resin in a small amount, a latent curing agent, for example, a cationic polymerization initiator such as a sulfonium salt or an iodonium salt (for example, an antimony-based cationic polymerization initiator, a boron-based cationic polymerization initiator, etc.) It has been known.

However, when a bisphenol A type epoxy resin and an antimony-based cationic polymerization initiator are combined, the composition has high storage stability, but the curability decreases, and curing at high temperature is required. On the other hand, when a boron-based cationic polymerization initiator is used, the reactivity is greatly improved, and although the epoxy resin composition can be cured at low temperature, the storage stability is extremely lowered and the epoxy resin composition is stored at low temperature (for example, refrigerator). There is a need to.

An epoxy resin having a 9,9-bisphenylfluorene skeleton is also known as an epoxy resin having higher heat resistance than the bisphenol A type epoxy resin. For example, Japanese Patent No. 3659532 (Patent Document 1) describes a resin composition containing an epoxy resin represented by the following formula and a curing agent.

(In the formula, n is an average value of 0 to 20, R is a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms, and G is a glycidyl group.)

This document describes amine compounds, acid anhydride compounds, amide compounds, and phenol compounds as curing agents, and in the examples, acid anhydride compounds are used as curing agents.

JP-A-2009-155256 (Patent Document 2) describes an epoxy resin represented by the following formula, and an amine-based curing agent, an acid anhydride-based curing agent, and a phenol resin curing agent as a curing agent. ing.

(In the formula, ring Z is a condensed polycyclic aromatic hydrocarbon ring, R ¹ is a cyano group, R ² is an alkylene group, R ³ is a hydrogen atom or a methyl group, and R ⁴ is a hydrocarbon. A group or the like, k is an integer of 0 to 4, m is an integer of 1 or more, n is 0 or an integer of 1 or more, and p is an integer of 1 or more.)

However, a resin composition containing an epoxy resin having these fluorene skeletons and these curing agents can also achieve both storage stability and pot life and curability, as described above. Have difficulty. Furthermore, it is expected that the reactivity (curability) will be reduced in epoxy resins having a large number of repeating alkyleneoxy groups, including epoxy resins having a fluorene skeleton.

Japanese Patent Laid-Open No. 2008-20842 (Patent Document 3) discloses a photosensitive resin composition containing a cationic photopolymerization initiator which is sulfonium tris(pentafluoroethyl)trifluorophosphate and an epoxy resin represented by the following formula. Is listed.

(In the formula, R represents alkylene, n represents an average value, and represents a positive real number of 0 to 20)

In such a photosensitive resin composition, since the epoxy resin has a high viscosity, it is diluted with an organic solvent and applied to the substrate.
Japanese Patent No. 3659532 (Claim 1, [0024], Example) JP, 2009-155256, A (claim 1, [0106]). JP, 2008-20842, A (claim 1, example)

Therefore, an object of the present invention is to provide an epoxy resin composition and a cured product thereof which are compatible with storage stability and pot life and curability.

Another object of the present invention is an epoxy resin that is expected to have low reactivity (such as a fluorene skeleton-containing epoxy resin), and even if it contains a boron-based cationic polymerization initiator, it can be stored with high stability, and An object is to provide a low temperature curable epoxy resin composition and a cured product thereof.

Still another object of the present invention is to provide an epoxy resin composition which has high curability and can be cured at low temperature even if the amount of the polymerization initiator used is small, and a cured product thereof.

The inventors of the present invention have conducted extensive studies to achieve the above-mentioned object, and as described above, when the bisphenol A type epoxy resin is combined with a boron-based cationic polymerization initiator, the storage stability (storage stability) becomes extremely high. Therefore, other epoxy resins (for example, epoxy resins having a 9,9-bis(aryl)fluorene skeleton such as a 9,9-bis(phenyl)fluorene skeleton) have a large decrease in storage stability. Although expected, the presence or absence of addition of alkylene oxide (or the binding site of the glycidyl group) and the counter anion species greatly affect stability and curability (curing speed), and the alkyleneoxy group at the terminal has a glycidyl group. Surprisingly, when the epoxy resin with which is bonded and a boron-based cationic polymerization initiator are combined, it has high storage stability (storage stability) without thickening and exhibits high curability. It was found that although the reactivity decreases as the number of chain repeating units increases, it exhibits high curability (low temperature curability) and that even a small amount of a boron-based cationic polymerization initiator exhibits high curability. The present invention has been completed.

That is, the epoxy resin composition of the present invention contains an epoxy resin and a cationic polymerization initiator, and the epoxy resin is an epoxy resin having an oxirane ring-containing group represented by the following formula (1) at the terminal. In addition, it contains an onium salt containing a boron-based anion as the polymerization initiator.

(In the formula, R ¹ represents an alkylene group, R ² represents a hydrogen atom or a methyl group, and n represents an integer of 1 to 30).

The epoxy resin may be a compound having a 9,9-bisarylfluorene skeleton, for example, a compound represented by the following formula (1a) or a multimer thereof.

(In the formula, ring Z is an arene ring, R ^1a and R ^1b are each independently an alkylene group, R ² is a hydrogen atom or a methyl group, and R ³ and R ⁵ are each independently a substituent. , K is an integer of 0 to 4, n1 and n2 are each an integer of 1 to 30, p is an integer of 0 or 1 or more, and q is an integer of 1 or more).

For example, in the formula (1a), the ring Z may be a benzene ring, a naphthalene ring or a biphenyl ring, and R ^1a and R ^1b are each independently a linear or branched C _2-6 alkyl group. Alternatively, the average value of n1+n2 may be about 2 to 15, R ² may be a hydrogen atom, k and p may be 0, and q may be 1.

The onium salt containing a boron-based anion as a cationic polymerization initiator may contain a boron-based cationic polymerization initiator represented by the following formula (2), (3) or (4).

(In the formula, R ¹¹ represents an alkyl group, an alkenyl group, an alkynyl group, an aryl group which may have a substituent, an aralkyl group which may have a substituent, and R ¹² represents an alkyl group, a substituent Represents an optionally substituted aryl group, R ¹³ represents a hydrogen atom, a halogen atom, an alkyl group, a formyl group, a hydroxyl group, an alkoxy group or an acyloxy group, and R ¹⁴ represents a hydrogen atom, a halogen atom or an alkyl group. R ¹⁵ and R ¹⁶ each independently represent a hydrogen atom, a halogen atom or an alkyl group, and X represents a fluorine atom or a pentafluorophenyl group).

The onium salt may contain a boron-based cationic polymerization initiator represented by the following formula (2a) or (2b).

^{(Wherein, R 11a} is optionally _{C 1-4} alkyl _{group, C 1-4} alkyl optionally substituted _{C 6-12} also be an aryl group with a _group, substituted by _{C 1-4} alkyl groups _{C 6- 12} aryl- _C1-4 alkyl group is shown, ^R12a shows _C1-4 alkyl group, _C6-12 aryl group which may be substituted by the _C1-4 alkyl group, ^R13a is a hydrogen atom, C _1-4 alkyl _{group, C 1-4} alkyl - carbonyl _{group, C 6-12} aryl - indicates a carbonyl ^{group, R 14} represents a hydrogen atom, a halogen atom or a _{C 1-4} alkyl group.

R ^11b represents a hydrogen atom or a C _1-4 alkyl group, R ^12b represents a C _1-4 alkyl group, R ^13b represents a hydrogen atom, a C _1-4 alkyl group, a C _1-4 alkyl-carbonyl group)

In the epoxy resin composition, the ratio of the cationic polymerization initiator to 100 parts by weight of the epoxy resin may be about 0.01 to 10 parts by weight.

The present invention also includes a cured product obtained by curing the epoxy resin composition.

In this specification, an epoxy resin and an epoxy compound may be used interchangeably. Further, the epoxy resin having an oxirane ring-containing group represented by the formula (1) does not include a reactive diluent unless otherwise specified.

Since the epoxy resin composition of the present invention is a combination of a predetermined epoxy resin and an onium salt containing a boron-based anion as a cationic polymerization initiator, high storage stability and pot life (pot life), and high It can achieve both curability. Further, even an epoxy resin (for example, an epoxy resin containing a fluorene skeleton), which has a large number of repeating alkyleneoxy groups and is expected to have low reactivity, can be stored with high stability and can be cured at a low temperature. Further, even if the amount of the polymerization initiator used is small, it has high curability and can be cured at low temperature. Therefore, the handleability and workability of the epoxy resin composition can be improved.

[Epoxy resin]
The epoxy resin has an oxirane ring-containing group represented by the above formula (1) (for example, glycidyl(oxyalkylene)oxy group) at the terminal.

In the formula (1), examples of the alkylene group represented by R ¹ include ethylene group, propylene group, trimethylene group, tetramethylene group, 1,2-butanediyl group, 1,3-butanediyl group, pentamethylene group. A straight-chain or branched-chain C _2-6 alkylene group such as a hexamethylene group can be exemplified. The alkylene group is preferably a linear or branched C _2-4 alkylene group (for example, a linear C _2-3 alkylene group), and more preferably an ethylene group.

R ² represents a hydrogen atom or a methyl group, and is usually a hydrogen atom.

The coefficient n can be selected from an integer of 1 to 30 and may be an integer of, for example, 1 to 15 (for example, 1 to 10), preferably 1 to 7 (for example, 1 to 5), and 1 to 4 ( For example, it may be an integer of 1 to 3), especially 1 or 2 (particularly 1). Note that the composition containing the compound having a coefficient n of 1 or more (for example, 2 or more) seems to have improved stability.

That is, in the present invention, an epoxy resin obtained by reacting an alcoholic hydroxyl group (hydroxyalkyl group of an alkylene oxide adduct) with epihalohydrin or halomethyloxirane is used as an epoxy resin combined with a boron-based cationic polymerization initiator. Although the reason is not clear, the epoxy resin in which a phenolic hydroxyl group such as bisphenol A is reacted with epihalohydrin or halomethyloxirane has a markedly reduced stability when combined with a boron-based cationic polymerization initiator. Further, even if it has a (poly)alkyleneoxy group, an epihalohydrin or a halo group is present on the hydroxyl group of the benzene ring (for example, a benzene ring such as bisphenol A skeleton) located at both ends through the (poly)oxyalkylene chain. The epoxy resin reacted with methyloxirane also has a markedly reduced stability when combined with a boron-based cationic polymerization initiator.

The epoxy resin used in the present invention includes, for example, a compound in which a functional group having an active hydrogen atom is bonded to an aromatic ring (for example, a di- or trihydroxyarene compound, a di- or tricarboxyarene compound, a mono- or diaminoarene compound, etc.) Epoxy resins of alkylene oxide adducts (adducts or addition polymers with epihalohydrin or halomethyloxirane) are included. Specifically, glycidyl ether type epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin and the like are included. Examples of the glycidyl ether type epoxy resin include alkylene oxide adducts of bisphenols (for example, C _1-10 alkylenebisphenols such as bisphenol A, bisphenol F, and bisphenol AD, 9,9-bis(hydroxyaryl)fluorene). Glycidyl ether; glycidyl ether of alkylene oxide adduct of biarene diol (4,4′-biphenyl diol, etc.); glycidyl ether of alkylene oxide adduct of condensed ring arene diol (2,6-naphthalene diol), novolak type Examples thereof include glycidyl ether of an alkylene oxide adduct of a phenol resin (phenol novolac type phenol resin, cresol novolac type phenol resin). Examples of the glycidyl ester type epoxy resin include glycidyl ethers of alkylene oxide adducts of aromatic or alicyclic dicarboxylic acids (phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, etc.), and the like. Examples include glycidyl ethers of alkylene oxide adducts of aromatic or alicyclic amines (diaminodiphenylmethane, aminophenol, metaxylylenediamine, bisaminomethylcyclohexane, etc.).

Examples of the alkylene oxide include C _2-6 alkylene oxide such as ethylene oxide and propylene oxide. The number of moles of alkylene oxide added may be about 1 to 30 moles based on the hydroxyl group. These epoxy resins can be used alone or in combination of two or more kinds.

Unlike the reactive diluent, the epoxy resin has a relatively high viscosity and often has a plurality of arene rings and a plurality of oxirane ring-containing groups represented by the formula (1). The viscosity of the epoxy resin is often 700 mPa·s or more, particularly 1000 mPa·s or more, or a solid at a temperature of 25°C.

A preferred epoxy resin is an epoxy resin having a bisphenol skeleton (particularly, a bisphenol type epoxy resin, an epoxy resin having a 9,9-bisarylfluorene skeleton). The epoxy resin may be a multimer of an epoxy compound, for example, a dimer, a trimer, a tetramer, a pentamer, or another dimer to decamer. Such an epoxy resin can be represented by, for example, the following formula (1A).

[Where A is the following formula (A)

(Ring Z represents an arene ring, R ^1a and R ^1b each independently represent an alkylene group, n1 and n2 each represent an integer of 1 to 30, R ³ represents a substituent, and p represents 0 or 1 indicates an integer equal to or greater than, R ⁴ is a direct bond, an alkylene group, cycloalkylene group, arylene group, or the following formula (B)

(R ⁵ is a substituent, k is 0 or an integer of 1 or more), r is an integer of 0 or 1 or more, and R ² is the same as the above].

Examples of the alkylene group represented by R ⁴ include a linear or branched C _1-10 alkylene group such as a methylene group, an ethylene group, an ethylidene group, an isopropylidene group, and a butane-2,2-diyl group. it can. Examples of the cycloalkylene group include C _3-10 cycloalkylene groups such as cyclohexylidene group (cyclohexane-1,1-diyl group) and the like, and examples of the arylene group include C _6-10 arylene group such as phenylene group. It can be illustrated.

Preferred R ⁴ has a direct bond, a linear or branched C _1-6 alkylene group [especially isopropylidene group (=C(CH ₃ ) ₂ )], and a substituent in the formula (B). It may be a fluorene-9,9-diyl group. That is, a preferable epoxy resin is a bisphenol type epoxy resin such as a bisphenol A type epoxy resin, and an epoxy resin having a 9,9-bisarylfluorene skeleton.

The epoxy resin having a 9,9-bisarylfluorene skeleton is usually an epoxy compound in which an aryl group substituted at the 9,9-position of fluorene is substituted with a glycidyl ether group via a (poly)alkyleneoxy group. Alternatively, a multimer thereof (such as a dimer to a 10mer) can be used. Such an epoxy resin may be, for example, a compound represented by the following formula (1a) or a polymer thereof.

(In the formula, q represents an integer of 1 or more, and rings Z, R ^1a and R ^1b , R ² , R ³ , R ⁵ , k, n1 and n2, and p are the same as above).

In the above formulas (A) and (1a), the arene ring represented by ring Z is a monocyclic hydrocarbon ring such as a benzene ring or a condensed polycyclic aromatic hydrocarbon ring [condensed bicyclic hydrocarbon ring (For example, C _8-20 condensed bicyclic hydrocarbon such as naphthalene ring and indene ring, preferably C _10-16 condensed bicyclic hydrocarbon ring), condensed tricyclic hydrocarbon ring (for example, anthracene ring, phenanthrene ring) A fused bi- to tetracyclic hydrocarbon ring such as a ring), a ring-assembled arene ring [a bi-C _6-12 arene ring such as a bi-phenyl ring or a binaphthyl ring, and preferably a bi-C _6-10 arene. Ring, especially a biphenyl ring, etc.), a terarene ring (for example, a ter C _6-12 arene ring such as a terphenyl ring, etc.)] can be exemplified. Particularly, a C _6-10 arene ring (benzene ring, naphthalene ring, etc.) and a bi C _6-10 arene ring (biphenyl ring, etc.) are preferable. The two rings Z (for example, the two rings Z substituting at the 9-position of fluorene in formula (1a)) may be the same or different rings, and generally the same ring is preferable.

When R ⁴ in the formula (A) is a direct bond, an alkylene group, a cycloalkylene group, or an arylene group (particularly an alkylene group), the ring Z is often a benzene ring.

In the formula (1a), the substitution position of the ring Z substituting at the 9-position of fluorene is not particularly limited, and when the ring Z is a naphthalene ring, for example, 1-naphthyl is present at the 9-position of fluorene. It may be substituted with a group or a 2-naphthyl group. Further, when the ring Z is a ring-assembled arene ring, for example, a biphenyl ring, the 3-position or 4-position of the biphenyl ring may be bonded to the 9-position of fluorene.

The alkylene group represented by R ^1a and R ^1b is an alkylene group represented by R ¹ (for example, a linear or branched C _2-6 alkylene group, preferably a linear or branched C _{2 — group). It is the same as a 4} alkylene group (for example, linear _C2-3 alkylene group). The types of alkylene groups represented by R ^1a and R ^1b may be the same or different.

The coefficients n1 and n2 can be selected from integers of 1 to 30 similarly to the coefficient n, and are, for example, 1 to 15 (for example, 1 to 10), preferably 1 to 7 (for example, 1 to 5). Or an integer of 1 to 4 (for example, 1 to 3), especially 1 or 2 (in particular 1). The average value of n1+n2 can be selected from the range of about 2 to 30 (for example, 2 to 20), for example, 2 to 17 (for example, 2 to 15), preferably 2 to 12 (for example, 2 to 10). It may be about 2 to 6 (for example, 2 to 4), particularly about 2 to 3 (for example, 2). In addition, when a compound having an average value of n1+n2 of 3 or more (for example, 4 or more) is used, the stability of the composition containing the predetermined polymerization initiator seems to be further improved. When n1 and n2 are each 2 or more, the alkylene groups (R ^1a and R ^1b ) in the oxyalkylene chain may be the same or different.

It is expected that when the coefficients n1 and n2 (the number of repeating alkyleneoxy groups) increase, the curability of the epoxy resin decreases. Contrary to such expectations, in the present invention, high curability can be achieved even if the coefficient n (n1 and n2) (the number of repeating alkyleneoxy groups) is large. Moreover, it shows high curability even with a small amount of a curing agent (cationic polymerization initiator).

Each coefficient q is an integer of 1 or more, and is usually 1 to 3, preferably 1 or 2, and particularly 1.

Examples of the substituent represented by R ³ include a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), hydrocarbon group, hydroxyl group, alkoxy group (methoxy group, ethoxy group, propoxy group, n- Linear or branched C _1-10 alkoxy group such as butoxy group, isobutoxy group, t-butoxy group), cycloalkoxy group (C _5-10 cycloalkyloxy group such as cyclohexyloxy group), aryl Oxy group (C _6-10 aryloxy group such as phenoxy group), aralkyloxy group (C _6-10 aryl-C _1-4 alkyloxy group such as benzyloxy group), mercapto group, alkylthio group (methylthio group) , A C _1-10 alkylthio group such as an ethylthio group, a propylthio group, an n-butylthio group and a t-butylthio group), a cycloalkylthio group (a C _5-10 cycloalkylthio group such as a cyclohexylthio group), an arylthio group ( C _6-10 arylthio group such as thiophenoxy group), aralkylthio group (C _6-10 aryl-C _1-4 alkylthio such as benzylthio group), acyl group (C _1-6 alkyl-carbonyl such as acetyl group) Group), a carboxyl group, an alkoxycarbonyl group (such as a C _1-4 alkoxy-carbonyl group such as a methoxycarbonyl group), a substituted amino group (a dialkylamino group (for example, a diC _1-4 alkylamino group such as a dimethylamino group) Etc.), a dialkylcarbonylamino group (for example, a diC _1-4 alkyl-carbonylamino group such as a diacetylamino group), a nitro group, a cyano group, etc. Examples of the hydrocarbon group include an alkyl group (methyl group). , A linear or branched C _1-10 alkyl group such as ethyl group, propyl group, isopropyl group, butyl group, s-butyl group, t-butyl group), cycloalkyl group (cyclopentyl group, cyclohexyl group) Groups such as C _5-10 cycloalkyl groups), aryl groups [phenyl groups, alkylphenyl groups (methylphenyl (tolyl) groups, dimethylphenyl (xylyl) groups, etc.), naphthyl groups, C _6-12 such as biphenyl groups, etc. Aryl group], aralkyl group (benzyl group, C _6-10 aryl-C _1-4 alkyl group such as phenethyl group, etc.), etc. The hydrocarbon group is an alkyl group (straight or branched chain such as methyl group). C _1-6 alkyl group, preferably linear or In many cases, it is a branched chain C _1-4 alkyl group or the like) or an aryl group (C _6-10 aryl group such as a phenyl group).

Preferred substituent R ³ is a halogen atom, a hydrocarbon group, an alkoxy group, a cycloalkyloxy group, an aryloxy group, an aralkyloxy group, an acyl group, an alkoxycarbonyl group, a nitro group, a cyano group, a substituted amino group (particularly, a halogen atom). Atom, alkyl group (linear or branched C _1-6 alkyl group such as methyl group), aryl group (C _6-10 aryl group such as phenyl group), alkoxy group (linear group such as methoxy group) Or a branched C _1-4 alkoxy group, etc.), and is often an alkyl group (particularly, methyl group) or an aryl group (phenyl group, etc.). When the group R ³ is an aryl group, the group R ³ and the ring Z may each form the ring-collecting arene ring.

The coefficient p is 0 or an integer of 1 or more, for example, 0 to 8 (for example, 0 to 6), preferably 0 to 5 (for example, 0 to 4), and more preferably 0 to 2 (depending on the ring Z. For example, it may be 0 to 1), especially 0. In the same ring Z, when p is plural (2 or more), the types of the groups R ³ may be the same or different from each other, and in the two rings Z, the substitution numbers p are the same or different from each other. May be. Further, for example, when p is 1, the ring Z may be a benzene ring, a naphthalene ring or a biphenyl ring, and R ³ may be a methyl group or a phenyl group.

Examples of the substituent represented by R ⁵ include a hydrocarbon group (a hydrocarbon group similar to the above R ³ , particularly a linear or branched C _1-4 alkyl group such as a methyl group), a cyano group, a halogen atom. (Fluorine atom, chlorine atom, bromine atom, iodine atom) and the like can be exemplified. A preferred substituent R ⁵ is a C _1-4 alkyl group such as a methyl group.

The coefficient k is 0-4, preferably 0-1 and especially 0. In the two benzene rings forming fluorene in formula (1a), the coefficients k may be the same or different from each other. In addition, in the two benzene rings forming the fluorene skeleton, the types of the substituent R ⁵ may be the same or different. When k is plural (two or more), the kinds of the substituents R ⁵ may be the same or different from each other. The substitution position of the group R ⁵ with respect to the benzene ring forming fluorene is not particularly limited, and may be, for example, the 2-position to the 7-position of the fluorene ring.

Further, the epoxy resin may be a mixture or composition of a monomer (for example, a monomer of the compound represented by the formula (1a)) and the multimer. The ratio of the multimer is, for example, 0 to 25 parts by weight, preferably 0 to 15 parts by weight (for example, 0.1 to 10 parts by weight), and more preferably 100 parts by weight of the total amount of the monomer and the multimer. May be about 0 to 5 parts by weight (for example, 0.2 to 3 parts by weight).

The epoxy equivalent of the epoxy resin is, for example, 200 to 1500 g/eq (eg, 250 to 1000 g/eq), preferably 250 to 800 g/eq (eg, 270 to 700 g/eq), and more preferably 300 to 600 g/eq. (For example, about 350 to 500 g/eq) may be sufficient.

In addition, the substituent having an oxyalkylene group (glycidyloxyalkoxy group or the like) is represented by the formula (1A) (1a) and, when the ring Z is a benzene ring, the 3-position and/or the 4-position of the phenyl group. In many cases, when the ring Z is a naphthalene ring in the formula (1a), it is often at the 5 to 8 positions of the naphthyl group. For example, with respect to the 9-position of fluorene, In many cases, the substitution is performed in the relationship of 1,5-position, 2,6-position, and the like. Further, in the formula (1a), the 3-position or 4-position of the biphenyl ring may be bonded to the 9-position of fluorene, and the 3-position of the biphenyl ring may be bonded to the 9-position of fluorene. When the substituent has an oxyalkylene group (glycidyloxy group, etc.), the substituent has a 2-,6-,3′-,4′-,5′-position, preferably a 2-,6-,4′-position ( In particular, 2-position, 6-position) may be substituted.

Representative compounds in the formula (1a) include 9,9-bis(glycidyloxyaryl)fluorene, 9,9-bis(glycidyl-(mono- or poly)oxy linear or branched alkoxyaryl)fluorene, For example, 9,9-bis (glycidyl - (mono or poly) oxy linear or branched _{C 2-6} alkoxy _{C 6-12} aryl) fluorene, preferably 9,9-bis (glycidyl - (mono or poly ) Oxy linear or branched C _2-4 alkoxy C _2-4 alkoxy C _6-12 aryl)fluorene and the like.

More specifically, the following compounds (or epoxy resins) can be exemplified as typical compounds represented by the formula (1a).

(A) 9,9-bis(glycidyloxy(poly)alkoxyphenyl)fluorenes: For example, 9,9-bis(glycidyloxyalkoxyphenyl)fluorene {for example, 9,9-bis[4-(2-glycidyloxy) Ethoxy)phenyl]fluorene, 9,9-bis[4-(2-glycidyloxypropoxy)phenyl]fluorene and other 9,9-bis(glycidyloxy C _2-6 alkoxyphenyl)fluorene}, 9,9-bis( Alkyl-glycidyloxyalkoxyphenyl)fluorene (eg, 9,9-bis[4-(2-glycidyloxyethoxy)-3-methylphenyl]fluorene, 9,9-bis[4-(2-glycidyloxypropoxy)- 9,9-bis(mono- or di-C _1-4 alkyl-glycidyloxy, such as 3-methylphenyl]fluorene, 9,9-bis[4-(2-glycidyloxyethoxy)-3,5-dimethylphenyl]fluorene C _2-6 alkoxyphenyl)fluorene} (in the formula (1a), ring Z is a benzene ring, R ^1a and R ^1b are linear or branched C _2-6 alkylene groups (especially C _2-4 alkylene). A group), a compound in which R ³ is a hydrogen atom or an alkyl group, and n1 and n2 are 1) and the like;

(B) 9,9-bis(aryl-glycidyloxyalkoxyphenyl)fluorene {for example, 9,9-bis[4-(2-glycidyloxyethoxy)-3-phenylphenyl]fluorene, 9,9-bis[4 9,9-bis such as -(2-glycidyloxypropoxy)-3-phenylphenyl]fluorene and the like 9,9-bis(mono or di C _6-10 aryl-glycidyloxy C _2-6 alkoxyphenyl)fluorene} (Glycidyloxyalkoxyphenyl)fluorenes (in the formula (1a), the ring Z is a benzene ring, and R ^1a and R ^1b are linear or branched C _2-6 alkylene groups (particularly C _2-4 alkylene groups). ), a compound in which R ³ is a benzene ring, and n1 and n2 are 1) and the like;

(C) 9,9-bis(glycidyloxy(poly)alkoxynaphthyl)fluorenes: For example, compounds corresponding to the above-mentioned compounds (a) and (b), wherein ring Z is a naphthalene ring, for example, 9,9- Bis(glycidyloxyalkoxynaphthyl)fluorene {for example, 9,9-bis[6-(2-glycidyloxyethoxy)-2-naphthyl]fluorene, 9,9-bis[6-(2-glycidyloxypropoxy)-2. -Naphthyl]fluorene and other 9,9-bis(glycidyloxy C _2-6 alkoxynaphthyl)fluorene} and other 9,9-bis(glycidyloxyalkoxynaphthyl)fluorenes (in the formula (1a), ring Z is naphthalene) A ring, R ^1a and R ^1b are linear or branched C _2-6 alkylene groups (in particular, C _2-4 alkylene groups), p=0, and compounds in which n1 and n2 are 1) and the like;

(D) A compound corresponding to these compounds (a) to (c) and having n1 and n2 of 2 or more, for example, 9,9-bis(glycidyloxydialkoxyphenyl)fluorene {for example, 9,9-bis. {4-[2-(2-glycidyloxyethoxy)ethoxy]phenyl}fluorene and other 9,9-bis(glycidyloxydiC _2-6 alkoxyphenyl)fluorene} and other 9,9-bis(glycidyloxypolyalkoxy) Phenyl)fluorenes (a compound of the formula (1a) or compounds (a) to (c) in which n1 and n2 are 2 to 10) and the like.

As specific compounds represented by the formula (1a), for example, compounds in which the ring Z is a benzene ring, k=0, q=1, and R ² is a hydrogen atom can be exemplified in Table 1 below. Table 2 can illustrate compounds having a naphthalene ring, k=0, p=0, q=1, and R ² is a hydrogen atom. In addition, in Tables 1 and 2, the “substitution position” indicates the substitution position of the substituent having an oxyalkylene group (glycidyloxyalkoxy group or the like) with respect to the ring Z.

In the formula (1A), a compound in which R ⁴ is a fluorene-9,9-diyl group represented by the formula (B) (for example, an epoxy compound represented by the formula (1a) or a multimer thereof) is High rate and high heat resistance. Therefore, in the formula (1A), the applicable range can be expanded as compared with an epoxy resin in which R ⁴ is an alkylene group (typically, an epoxy resin having a bisphenol A skeleton).

The epoxy compound represented by the formula (1a) or a multimer thereof is prepared by subjecting the compound corresponding to the formula (1a) to, for example, 9, It can be produced by reacting 9-bis(hydroxy(poly)alkoxyaryl)fluorenes with epihalohydrin (eg, epichlorohydrin, epibromohydrin, etc., particularly epichlorohydrin). Further, 9,9-bis(hydroxy(poly)alkoxyaryl)fluorenes may be produced by adding alkylene oxides (ethylene oxide, propylene oxide, etc.) to 9,9-bis(hydroxyaryl)fluorenes. It may well be formed by reacting with an alkylene carbonate (ethylene carbonate, propylene carbonate, etc.) and/or a haloalkanol (halo C _2-6 alkanol, such as 2-chloroethanol, 3-bromopropanol, etc.).

[Other epoxy resins]
The epoxy resin (or epoxy compound) having the oxirane ring-containing group represented by the formula (1) can be used alone or in combination of two or more kinds. Further, the epoxy resin (or epoxy compound) having an oxirane ring-containing group represented by the formula (1) may be used as an epoxy resin component in combination with another epoxy resin, if necessary. As other epoxy resin, in the oxirane ring-containing group represented by the formula (1), n is 0 (that is, alkylene oxide is not added), for example, glycidyl ether type epoxy resin [bisphenol type Epoxy resin (bisphenol A type epoxy resin, bisphenol F type epoxy resin, etc.), biphenyl type epoxy resin, novolac type epoxy resin (phenol novolac type epoxy resin, cresol novolac type epoxy resin, etc.), triphenol alkane type epoxy resin, phenol aralkyl Type epoxy resin, heterocyclic epoxy resin, stilbene type epoxy resin, condensed ring aromatic hydrocarbon modified epoxy resin (1,6-bis(glycidyloxy)naphthalene, etc.)], glycidyl ester type epoxy resin, glycidyl amine type epoxy resin And alicyclic epoxy resins. These other epoxy resins may be used alone or in combination of two or more.

The ratio of the epoxy resin having the oxirane ring-containing group represented by the formula (1) with respect to the entire epoxy resin component is, for example, 50 to 99% by weight, preferably 60 to 98% by weight, more preferably 70 to 95% by weight. It may be a degree.

[Curing agent]
The epoxy resin composition of the present invention is combined with a cationic polymerization initiator (thermal polymerization initiator) as a curing agent to form a thermosetting resin composition. That is, the present inventors have found that the counter anion species of the cationic polymerization initiator (onium salt) greatly affects the stability (storage or storage stability) of the epoxy resin. More specifically, when an onium salt containing a boron (or boron) anion is used, not only the storage stability of an epoxy resin (such as an epoxy resin having a fluorene skeleton) is significantly improved, but also a small amount is used. Can greatly improve the curability (reactivity) of the epoxy resin and can be cured at low temperatures. More specifically, when an onium salt containing an antimony anion is used, a typical bisphenol A type epoxy resin has low reactivity and needs to be cured at high temperature. On the other hand, when an onium salt containing a boron (or boron) anion is mixed, the bisphenol A type epoxy resin immediately reacts and hardens, so the epoxy resin composition needs to be stored at a low temperature (such as in a refrigerator).

On the other hand, when an epoxy resin (such as an epoxy resin having a fluorene skeleton) and an onium salt containing a boron (or boron) anion are combined, the storage stability (or storage stability) is high and the onium salt Even if the amount used is small, the curing speed is high and it can be cured at low temperature. For example, even if an epoxy resin and an onium salt containing a boron (or boron) anion are mixed, the composition does not thicken even after 2 weeks, has extremely high storage stability, and can be cured at a low temperature. is there. In particular, an epoxy resin having a large number of repeating oxyalkylene groups (R ¹ O) [or (R ^1a O)/(R ^1b O)] and having low reactivity (such as an epoxy resin having a fluorene skeleton) ), it is possible to achieve both high storage stability and high curability as described above.

The curability of the epoxy resin composition can be evaluated by the exothermic peak temperature measured by a differential scanning calorimeter (DSC), and it can be determined that the lower the exothermic peak temperature, the lower the temperature will be.

The cationic polymerization initiator may be an onium salt containing a boron (or boron) anion, and the type of cation is not particularly limited, and may be, for example, a sulfonium cation or an iodonium cation. Such an onium salt may contain, for example, a boron-based cationic polymerization initiator represented by the following formula (2), (3) or (4).

(In the formula, R ¹¹ represents an alkyl group, an alkenyl group, an alkynyl group, an aryl group which may have a substituent, an aralkyl group which may have a substituent, and R ¹² represents an alkyl group, a substituent Represents an optionally substituted aryl group, R ¹³ represents a hydrogen atom, a halogen atom, an alkyl group, a formyl group, a hydroxyl group, an alkoxy group or an acyloxy group, and R ¹⁴ represents a hydrogen atom, a halogen atom or an alkyl group. R ¹⁵ and R ¹⁶ each independently represent a hydrogen atom, a halogen atom or an alkyl group, and X represents a fluorine atom or a pentafluorophenyl group.)

Examples of the alkyl group represented by R ¹¹ include linear or branched C _1-6 such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, s-butyl group, and t-butyl group. An alkyl group etc. can be illustrated. A preferred alkyl group is a linear or branched C _1-4 alkyl group, particularly a C _1-2 alkyl group (methyl group or ethyl group).

Examples of the alkenyl group include linear or branched C _2-6 alkyl groups such as vinyl group, allyl group, 1-propenyl group, isopropenyl group and butenyl group. Examples of the alkynyl group include linear or branched C _2-6 alkynyl groups such as ethynyl group, 2-propynyl group, 2-butynyl group, and 3-butynyl group. A preferable alkynyl group may be a linear or branched C _2-4 alkynyl group such as a 2-propynyl group (propargyl group) or a butynyl group.

Examples of the aryl group which may have a substituent include a C _6-12 aryl group such as a phenyl group and a naphthyl group. As the substituent of the aryl group, a halogen atom (fluorine, chlorine, bromine, iodine atom), an alkyl group similar to R ¹¹ (a linear or branched C _1-4 alkyl group, particularly a C _1-2 alkyl group) ) Can be illustrated. The substituents may be substituted at appropriate positions on the aryl group, for example, 2-position, 4-position, 3-position of the phenyl group, 5-position, 6-position of the naphthyl group.

Examples of the aralkyl group include C _6-12 aryl-C _1-4 alkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group and 2-naphthylmethyl group. Examples of the substituent of the aralkyl group include the same alkyl groups as R ¹¹ (linear or branched C _1-4 alkyl group, particularly C _1-2 alkyl group). The substituent may be substituted at a suitable position on the arene ring of the aralkyl group, for example, at the 4-position or 3-position of the phenyl group.

Examples of the alkyl group represented by R ¹² include the same alkyl groups as those of R ¹¹ (linear or branched C _1-4 alkyl group, particularly C _1-2 alkyl group). Examples of the aryl group which may have a substituent include the same aryl group which may have a substituent as the above R ¹¹ . R ¹² is often an alkyl group.

Examples of the halogen atom represented by R ¹³ include fluorine, chlorine, bromine and iodine atoms. Examples of the alkyl group include the same alkyl groups as those for R ¹¹ (linear or branched C _1-6 alkyl group, particularly C _1-4 alkyl group). Examples of the alkoxy group include linear or branched C _1-6 alkoxy groups such as methoxy group, ethoxy group, propoxy group, isopropoxy group, n-butoxy group, isobutoxy group and t-butoxy group. A preferable alkoxy group is a linear or branched C _1-4 alkoxy group, particularly a C _1-2 alkoxy group (methoxy group, ethoxy group).

Examples of the acyloxy group include linear or branched C _1-6 alkyl-carbonyl groups such as acetyloxy group, propionyloxy group, butyryloxy group and valeryloxy group, C ₆ such as benzoyloxy group and naphthoyloxy group. _{A -12} aryl-carbonyl group etc. can be illustrated. The arylcarbonyl group may have a substituent, for example, an alkyl group similar to R ¹¹ (a linear or branched C _1-4 alkyl group, particularly a C _1-2 alkyl group), and C _{A 1-4} alkyl C _6-12 aryl-carbonyl group (eg, a C _1-3 alkyl-benzoyloxy group such as a toluoyl group) may be formed.

R ¹³ is often a hydrogen atom, an alkyl group, a formyl group, a hydroxyl group, an alkoxy group, an acyloxy group (such as an acetyloxy group, a benzoyloxy group, an alkylbenzoyloxy group).

The halogen atom represented by R ¹⁴ may be a fluorine, chlorine, bromine or iodine atom. Examples of the alkyl group include the same alkyl groups as those for R ¹¹ (linear or branched C _1-4 alkyl group, particularly C _1-2 alkyl group). R ¹⁴ is usually a hydrogen atom, a halogen atom (such as a chlorine atom) or a C _1-3 alkyl group in many cases.

Examples of the halogen atom represented by R ¹⁵ and R ¹⁶ include the same halogen atom as R ¹³ . As the alkyl group, an alkyl group similar to R ¹¹ (linear or branched C _1-6 alkyl group, preferably linear or branched C _1-4 alkyl group, particularly C _1-3 alkyl group) is used. Group). Note that one of R ¹⁵ and R ¹⁶ is a straight-chain alkyl group (for example, a C _1-3 alkyl group such as a methyl group or an ethyl group), and the other substituent is a branched-chain alkyl group ( For example, a branched C _3-4 alkyl group such as isopropyl group, isobutyl group, s-butyl group) may be used. In many cases, R ¹⁵ and R ¹⁶ are each independently a hydrogen atom or a C _1-4 alkyl group.

X represents a fluorine atom or a pentafluorophenyl group, forming tetrafluoroborate (BF ₄ ) or tetrakis(pentafluorophenyl)borate (B(C ₆ F ₅ ) ₄ ).

The onium salt represented by the formula (2) may be, for example, an onium salt represented by the following formula (2a) (boron-based cationic polymerization initiator).

^{(Wherein, R 11} _{is, C 1-4} alkyl _{groups, C 1-4} alkyl optionally substituted _{C 6-12} also be an aryl group with a _{group, C 1-4} optionally substituted by an alkyl group _{C 6 -12} aryl-C _1-4 alkyl group (benzyl group optionally substituted by C _1-4 alkyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, etc.), C _2-6 alkynyl group (propargyl group) , Butynyl group), R ¹² represents a C _1-4 alkyl group, a C _6-12 aryl group which may be substituted with a C _1-4 alkyl group, and R ^13a represents a hydrogen atom, C _1-4. An alkyl group, a C _1-4 alkyl-carbonyl group (acetyl group or the like), an optionally substituted C _6-12 aryl-carbonyl group (benzoyl group, C _1-4 alkyl-benzoyl group), R ¹⁴ represents a hydrogen atom, a halogen atom or a C _1-4 alkyl group)

Further, the onium salt represented by the formula (2) may be, for example, an onium salt represented by the following formula (2b) (boron-based cationic polymerization initiator).

(In the formula, R ¹¹ represents a hydrogen atom or a C _1-4 alkyl group, R ¹² represents a C _1-4 alkyl group, R ^13a represents a hydrogen atom, a C _1-4 alkyl group, a C _1-4 alkyl-carbonyl group. )

As a typical onium salt represented by the formula (2), when tetrakis(pentafluorophenyl)borate is represented as “B(C ₆ F ₅ ) ₄ ”, for example, R ¹¹ is an aralkyl group and R ¹² is an alkyl group. Group, a compound in which R ¹³ is a hydroxyl group, for example, 4-hydroxyphenyl(benzyl)methylsulfonium B(C ₆ F ₅ ) ₄ , 4-hydroxyphenyl(2-methylbenzyl)methylsulfonium B(C ₆ F ₅ ). _4, 4-hydroxyphenyl (dimethyl) sulfonium B _{(C 6} F ₅₎ 4, 4-hydroxyphenyl (1-naphthylmethyl) methyl sulfonium B _{(C 6} F ₅₎ 4, 4-hydroxyphenyl (2-naphthylmethyl) Methylsulfonium B(C ₆ F ₅ ) _{4 and the} like; compounds in which R ¹¹ is an alkynyl group, R ¹² is an alkyl group, and R ¹³ is a hydroxyl group, for example, 4-hydroxyphenylpropargylmethylsulfonium B(C ₆ F ₅ ) ₄ , 4-hydroxyphenyl-2-butynyl methyl sulfonium _{B (C 6 F 5) 4} , 4- hydroxy-3-methylphenyl-2-butynyl methyl sulfonium _{B (C 6 F 5) 4} , 4- hydroxyphenyl - 2-butynyl methyl sulfonium B _{(C 6} F _{5) 4,} ^{etc.; R 11} is an aralkyl ^{group, R 12} is an alkyl ^group, compound ^{wherein R 13} is an acyloxy group, e.g., 4-acetyloxy-phenyl (benzyl) methyl sulfonium B _{(C 6 F 5) 4,} 4- acetyloxy-phenyl (2-methylbenzyl) methyl sulfonium B _{(C 6} F ₅₎ 4, 4-acetyloxy-phenyl (4-methylbenzyl) methyl sulfonium B _{(C 6 F} 5) _4, 4-acetyloxy-phenyl-3-methylphenyl benzyl methyl sulfonium B _{(C 6} F ₅₎ 4, 4-acetyloxy-phenyl (dimethyl) sulfonium B _{(C 6} F ₅₎ 4, 4-acetyloxy-phenyl (1- naphthylmethyl) methyl sulfonium _{B (C 6 F 5) 4} , 4- acetyloxy-phenyl (2-naphthylmethyl) methyl sulfonium _{B (C 6 F 5) 4} , 4- benzoyloxy phenyl (dimethyl) sulfonium B _(C 6 F ₅ ) ₄ , benzyl-4-(4-to Le oil) phenyl methyl sulfonium _{B (C 6 F 5) 4} , 4- (4- toluoyl) phenyl methyl (1-naphthylmethyl) sulfonium _{B (C 6 F 5) 4} , (2- methylbenzyl) - 4-(4-toluoyloxy)phenylmethylsulfonium B(C ₆ F ₅ ) ₄ ; a compound in which R ¹¹ is an aryl group, R ¹² is an alkyl group, and R ¹³ is an acyloxy group, for example, 4-acetyloxyphenyl( phenyl) methyl sulfonium B _{(C 6} F ₅₎ 4, 4-acetyloxy-phenyl (4-tolyl) methyl sulfonium B _{(C 6} F _{5) 4,} ^{etc.; R 11} is an aryl ^{group, R 12} is an aryl ^{group, R 13} is compound an acyloxy group, e.g., 4-acetyloxy-phenyl (diphenyl) sulfonium _{B (C 6 F 5) 4} , 4- acetyloxy-phenyl (bis (4,4'-dimethyl) phenyl) sulfonium B _(C 6 _{F 5} ) _{4 and the} like; compounds in which R ¹¹ is an optionally substituted aryl group, R ¹² is an alkyl group, and R ¹³ is an alkyl group, for example, diphenylmethylsulfonium B(C ₆ F ₅ ) ₄ , 4- Examples include isopropylphenyl-4′-methylphenylmethylsulfonium B(C ₆ F ₅ ) _{4 and the} like.

Examples of the onium salt represented by the formula (3) include 4-branched compounds such as diphenylsulfonium B(C ₆ F ₅ ) ₄ and 4-isopropylphenyl-4′-methylphenylsulfonium B(C ₆ F ₅ ) _4. Examples include chain C _3-6 alkyl-4′-C _1-4 alkyldiphenylsulfonium B(C ₆ F ₅ ) _{4 and the} like.

Examples of the onium salt represented by the formula (4) include 4-branched compounds such as diphenyliodonium B(C ₆ F ₅ ) ₄ and 4-isopropylphenyl-4′-methylphenyliodonium B(C ₆ F ₅ ) _4. Examples include chain C _3-6 alkyl-4′-C _1-4 alkyldiphenyliodonium B(C ₆ F ₅ ) _{4 and the} like.

These compounds may be prepared by known methods (for example, methods according to WO 2012/042796, JP-A-2014-62057, etc.), or commercially available products may be used. For example, the onium salt may be obtained from Tokyo Kasei Kogyo Co., Ltd., available from Rhodia (or Solvay) under the product name “Lordsil 2074”, and from ADEKA Co., Ltd. under the product name “Adeka Optomer SP. -300", Sanshin Chemical Co., Ltd. "Sun-Aid SI-B2A" "San-Aid SI-B3A" "San-Aid SI-B3" "San-Aid SI-B4" "San-Aid SI-B5" and so on.

In the present invention, by combining and mixing such a cationic polymerization initiator (latent curing agent) and an epoxy resin (such as an epoxy resin having a fluorene skeleton), an epoxy having high storage stability and excellent curability is obtained. A resin composition is prepared.

The amount of the cationic polymerization initiator (onium salt) used can be selected within a range that does not impair the properties of the epoxy resin, and for example, 0.01 to 10 parts by weight (preferably 0.03 to 5) relative to 100 parts by weight of the epoxy resin. Parts by weight, more preferably about 0.05 to 2.5 parts by weight). Further, in the present invention, high curability (low temperature curability) is exhibited even when the amount of the cationic polymerization initiator used is small. Therefore, the ratio of the cationic polymerization initiator is, for example, 0.01 to 1 part by weight (e.g., 0.02 to 0.8 part by weight), preferably 0.03 to 0. It may be about 7 parts by weight (for example, 0.04 to 0.5 parts by weight), and more preferably about 0.05 to 0.3 parts by weight (for example, 0.07 to 0.2 parts by weight).

Note that, unlike the cationic polymerization initiator (onium salt), a curing agent such as an amine-based curing agent or an acid anhydride-based curing agent is used in a relatively large amount relative to the epoxy resin, for example, 100 parts by weight of the epoxy resin, It is used in a proportion of about 15 to 50 parts by weight. Therefore, the properties of the curing agent may be reflected in the properties of the cured product, and the original properties of the epoxy resin may not be exhibited. On the other hand, in the present invention, since the epoxy resin can be cured with a small amount of the cationic polymerization initiator, it is possible to suppress the deterioration of the characteristics of the cured product and to express the original characteristics of the epoxy resin.

The epoxy resin composition may include a reactive diluent. As the reactive diluent, a low-viscosity epoxy compound, for example, a monofunctional epoxy group-containing compound (for example, alkyl glycidyl ethers such as 2-ethylhexyl glycidyl ether, allyl glycidyl ether, glycidyl (meth)acrylate, etc. Aryl glycidyl ethers such as alkenyl glycidyl ethers, phenyl glycidyl ethers and pt-butylphenyl glycidyl ethers, glycidyl ethers such as glycidyl ethers of alkylene oxide adducts corresponding to these compounds; octylene oxide, styrene oxide , Polyfunctional epoxy compounds such as alkene oxides such as 4-vinylcyclohexene monooxide [eg, polyol polyglycidyl ether (butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, etc. Alkanediol diglycidyl ethers, trimethylolpropane di to triglycidyl ether, glycerin di to triglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, etc.), diglycidyl aniline, cyclohexane dimethanol diglycidyl ether, cyclo Alkene oxides (eg, vinylcyclohexenedioxide, methylated vinylcyclohexenedioxide, etc.), etc. These reactive diluents may be used alone or in combination of two or more.

The proportion of the reactive diluent may be, for example, 1 to 1000 parts by weight, preferably 5 to 500 parts by weight, more preferably 10 to 200 parts by weight, relative to 100 parts by weight of the epoxy resin.

In addition, if necessary, the epoxy resin composition (curable composition) may be another curing agent such as an amine curing agent, a polyaminoamide curing agent, a polyamide curing agent, an acid anhydride curing agent, or a phenol resin curing agent. It may contain a curing agent and may contain a cationic photopolymerization initiator.

Further, the curable composition may include a solvent. Examples of the solvent include aromatic hydrocarbons such as toluene and xylene; alicyclic hydrocarbons such as cyclohexane; aliphatic hydrocarbons such as hexane; esters such as methyl acetate, ethyl acetate and butyl acetate; acetone. , Ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ethers such as tetrahydrofuran; (di)alkylene glycol ethers such as cellosolves such as methyl cellosolve, ethyl cellosolve and butyl cellosolve, methyl carbitol, ethyl carbitol, butyl Carbitols such as carbitol; cellosolve acetates such as methyl cellosolve acetate and ethyl cellosolve acetate; alkylene glycol monoalkyl ether acetates such as propylene glycol monomethyl ether acetate; and lactones such as γ-butyrolactone. You may use these solvent individually or in combination of 2 or more types.

The use amount (addition amount) of the solvent can be selected from the range of 0 to 500 parts by weight, for example, 10 to 400 parts by weight, preferably 20 to 300 parts by weight, and further 100 parts by weight of the epoxy resin component. It may be preferably about 30 to 200 parts by weight.

The curable composition includes conventional additives such as colorants, stabilizers (heat stabilizers, antioxidants, UV absorbers, etc.), curing accelerators, fillers, reinforcing agents (granular or fibrous reinforcing agents). , An antistatic agent, a flame retardant, a flame retardant auxiliary agent, etc. may be contained. You may use an additive individually or in combination of 2 or more types.

[Cured product obtained by curing the curable composition]
The present invention also includes a cured product obtained by curing the epoxy resin composition. In the present invention, as described above, unlike a curing agent such as an acid anhydride-based curing agent, since the epoxy resin can be cured with a small amount of a cationic polymerization initiator, it is possible to suppress deterioration of the properties of the cured product, and the epoxy resin originally The characteristics of can be expressed. In particular, storage stability (storage stability) is high, pot life is long, and B stage (semi-curing, semi-cure) can be maintained, so handling is easy, and casting, sealing, lamination, and composite (composite material) are possible. Workability can be greatly improved in molding processing such as. Further, it may be cured at a low temperature depending on the kind of the cationic polymerization initiator.

The epoxy resin composition can produce a cured product by a conventional method, for example, by molding or processing in a predetermined form (for example, molding by using a predetermined mold) and curing by heating. For example, the epoxy resin composition may be fluidized by heating or the like, if necessary, and cast into a predetermined mold to be heat-cured to produce a cast insulator, and the epoxy resin and the base material (paper, A laminated board may be manufactured by preparing a prepreg with glass cloth, synthetic fiber cloth, etc., and laminating it with copper foil and curing it with heat. Epoxy resin is used as a matrix to reinforce glass fiber, carbon fiber, etc. The fiber reinforced composite material (FRP) may be manufactured by preparing a prepreg containing the agent, molding the prepreg into a predetermined shape, and heating and curing the prepreg. Further, the epoxy resin composition may be applied to the adhesion site or the sealing site and cured by heating, or the epoxy resin composition may be coated on the substrate and cured by heating.

The epoxy resin composition can be cured by heating at, for example, about 50 to 250° C., preferably 70 to 220° C., more preferably 80 to 200° C. (eg, 90 to 170° C.), and can be cured at a relatively low temperature (eg, It can also be cured at 50 to 170° C., preferably 70 to 150° C., more preferably about 80 to 130° C.).

Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to these Examples.

In the examples and comparative examples, the following epoxy resin (or epoxy compound) and curing agent (or cationic polymerization initiator) were used.

(A) Epoxy resin (or epoxy compound)
(A1) Epoxy resin having 9,9-bisarylfluorene skeleton The above epoxy resin was prepared according to Comparative Synthesis Example 1 of JP-A-2015-157936. That is, 0.57 mol of a compound (called "BPEF-10EO") obtained by adding 10 mol of ethylene oxide to 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (called "BPEF") on average, epichlorohydride Phosphorus 6.27 mol and trimethylammonium bromide (TMAB) 4.0 g (0.026 mol) were placed in a three-necked flask, the system was replaced with argon, and the temperature was raised to 50° C. to dissolve the above components, and then hydroxylated 32,9 g (8.0 mol) of sodium was added over 1 hour, the atmosphere was replaced with argon again, and the reaction was carried out at 80° C. for 9 hours, in the same manner as in Comparative Synthesis Example 1 of the above-mentioned document, 9,9-bis(4 A diglycidyl ether (epoxy compound) having a -(2-glycidyloxy(poly)ethoxy)phenyl)fluorene skeleton (referred to as "BPEF-10EOG") was obtained. The obtained epoxy compound had a solid content concentration of 99.5% by weight, a viscosity (25° C.) of 6,040 mPa·s, and an epoxy equivalent of 467 g/eq. Further, at a temperature of 25° C., the refractive index at a wavelength of 589 nm was 1.57, and the 5% weight loss temperature was 368° C. in the differential thermal/thermogravimetric (TG/DTA) simultaneous measurement device.

(A2) Digli was prepared in the same manner as in (A1) except that a compound obtained by adding 5 mol of ethylene oxide to 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (referred to as "BPEF") was used. A disil ether (epoxy compound) (referred to as "BPEF-5EOG") was obtained. The obtained epoxy compound had a solid content concentration of 99.2% by weight, a viscosity (25° C.) of 25,800 mPa·s, and an epoxy equivalent of 370 g/eq. Further, at a temperature of 25° C., the refractive index at a wavelength of 589 nm was 1.58, and the 5% weight loss temperature was 384° C. in the differential thermal/thermogravimetric (TG/DTA) simultaneous measurement device.

(A3) In the same manner as in (A1) except that a compound obtained by adding 15 mol of propylene oxide on average to 9,9-bis(6-hydroxy-2-naphthyl)fluorene (referred to as “BNF”) is used, diglycidylamine is used. Ruthel (epoxy compound) (referred to as “BNF-15POG”) was obtained. The viscosity (25° C.) of the obtained epoxy compound was 1,254 mPa·s, and the epoxy equivalent was 407 g/eq.

(A4) Ethylene oxide (EO) modified bisphenol A type epoxy resin (manufactured by Shin-Nippon Rika Co., Ltd., "Rikaresin BEO-60E", EO average added mole number 6 moles, viscosity (25°C) 800 to 1,600 mPa·s, Epoxy equivalent 345-385 g/eq). The refractive index at a wavelength of 589 nm was 1.53 at a temperature of 25° C., and the weight loss temperature of 5% was 346° C. in the differential thermal/thermogravimetric (TG/DTA) simultaneous measurement device.

(A5) Bisphenol A type epoxy resin: "JER828" manufactured by Mitsubishi Chemical Corporation

(A6) Ethylene oxide (EO) modified phenolic epoxy resin (“Epiclone EXA-4822” manufactured by DIC Corporation. This epoxy resin (A6) has a viscosity (25° C.) according to “Product Information” of DIC Corporation. It has an epoxy equivalent of 385 g/eq and has a glycidyl group bonded to the benzene ring of the bisphenol skeleton located at the end, not to the polyether chain. As above, since it has a high viscosity (solid state) at a temperature of 25° C., it was used as a 50 wt% solution of γ-butyrolactone.

(A7) 9,9-bis[4-(2-glycidyloxyethoxy)phenyl]fluorene (BPEF-G)
According to Synthesis Example 3 of JP2012-102228A, 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene (BPEF) (manufactured by Osaka Gas Chemicals Co., Ltd.) and epichlorohydrin were used. Was reacted to obtain a liquid epoxy resin at room temperature.

The obtained epoxy resin has a viscosity (150° C.) of 55 mPa·s, an epoxy equivalent of 278 g/eq, a refractive index of 1.62 at a wavelength of 589 nm at a temperature of 25° C., and a differential thermal/thermogravimetric (TG/DTA) simultaneous value. In the measuring device, the 5% weight loss temperature was 390°C.

(A8) 9,9-bis(4-glycidyloxyphenyl)fluorene (BPF-G)
According to Synthesis Example 2 of JP2012-102228A, 9,9-bis(4-hydroxyphenyl)fluorene (BPF) (manufactured by Osaka Gas Chemicals Co., Ltd.) and epichlorohydrin are reacted to give white. A powdered epoxy resin was obtained.

This epoxy resin had an average addition mole number of ethylene oxide (EO) of 0,9 mol with respect to 9,9-bis(4-hydroxyphenyl)fluorene, a viscosity (150° C.) of 285 mPa·s, and an epoxy equivalent of 250 g/eq. The refractive index at a wavelength of 589 nm was 1.64 at a temperature of 25° C., and the weight loss temperature of 5% was 354° C. in the differential thermal/thermogravimetric (TG/DTA) simultaneous measurement device.

(A9) 9,9-bis(6-glycidyloxy-2-naphthyl)fluorene (BNF-G)
According to Synthesis Example 1 of JP2012-102228A, 9,9-bis(6-hydroxy-2-naphthyl)fluorene (BNF) (manufactured by Osaka Gas Chemicals Co., Ltd.) and epichlorohydrin were reacted. Then, 9,9-bis(6-glycidyloxy-2-naphthyl)fluorene) was obtained in the form of a white powder.

This epoxy resin had an average number of moles of EO added to BNF of 0 mol, a viscosity (180° C.) of 3200 mPa·s, and an epoxy equivalent of 300 g/eq. The refractive index at a wavelength of 589 nm was 1.70 at a temperature of 25° C., and the weight loss temperature of 5% was 400° C. in the differential thermal/thermogravimetric (TG/DTA) simultaneous measurement device.

(B) Curing agent (cationic polymerization initiator)
_{(B1) B (C 6 F} 5) 4 boron-based polymerization initiator containing as the anion (Sanshin Chemical Co., Ltd. "San-Aid SI-B2A"): 4-Acetyl-oxyphenyl (2-methylbenzyl) methyl sulfonium tetrakis (pentafluorophenyl) borate _{(B (C 6 F 5)} 4)

(B2) Antimony-based cationic polymerization initiator containing SbF ₆ as an anion (“SI-100L” manufactured by Sanshin Chemical Co., Ltd.): Benzylmethyl p-hydroxyphenylsulfonium hexafluoroantimonate (SbF ₆ ).

(B3) Antimony-based cationic polymerization initiator containing SbF ₆ as an anion (“SI-60L” manufactured by Sanshin Chemical Co., Ltd.): 1-naphthylmethylmethyl p-hydroxyphenylsulfonium hexafluoroantimonate (SbF ₆ ).

Examples and Comparative Examples The epoxy resin and the curing agent (polymerization initiator) were mixed at a ratio shown in Table 3 at room temperature to prepare an epoxy resin composition. The epoxy resins (A6) to (A9) to (A9), which are solid at room temperature, and the epoxy resins (A6), (A8) and (A9), which are solid at room temperature, and the semi-solid and extremely viscous epoxy resin (A7) at room temperature, A 50% by weight γ-butyrolactone (GBL) solution was prepared in advance, and a curing agent was added to prepare an epoxy resin composition.

The exothermic peak temperature of the obtained epoxy resin composition was measured, and the viscosity was measured over time. The exothermic peak temperature was measured at a temperature of 30 to 250°C and a temperature rising rate of 10°C/min using a DSC measuring device [“DSC 6220” manufactured by SII Nano Technology Inc.). For the viscosity, according to JIS K7117-2, a TV-22 type viscometer [cone plate type, "TVE-22L" manufactured by Toki Sangyo Co., Ltd.] was used, and the type of optional rotor (01 1° 34′×R24, 07:3°×R7.7) and the number of revolutions (1 to 20 rpm) were selected, and measurement was performed at a temperature of 25° C.

The results are shown in Tables 3 and 4.

The evaluation criteria for storage stability are as follows.

"○": The composition to which the curing agent (cationic polymerization initiator) was added showed almost no increase in viscosity even after 7 days. "△": The composition to which the curing agent (cationic polymerization initiator) was added was observed after 2 to 4 days. The viscosity hardly increased, but the viscosity increased after 7 days. “X”: The composition to which the curing agent (cationic polymerization initiator) was added immediately reacted, gelled on the 1st day, and solidified after 7 days.

The compositions of Examples 1 to 4 and Comparative Examples 1 to 10 were stored at a temperature of 15 to 20°C, and the compositions of Example 5 and Comparative Examples 11 to 18 were stored at a temperature of 20 to 30°C.

From Tables 3 and 4, bisphenol A type epoxy resin (A5) and 9,9-bisarylfluorene type epoxy resin (A8) (A9), even if it has a (poly)oxyalkylene chain, phenolic property of the terminal When the boron-based cationic polymerization initiator (B1) was added to the epoxy resin (A6) in which the hydroxyl group was glycidyl etherified, the reaction immediately started in the composition (Comparative Examples 5, 8, 13 and 16), and the first day Gelled and solidified after 7 days.

On the other hand, even with the epoxy resin (A1) (A4) (A7) of the alkylene oxide adduct, the epoxy resin composition (Comparative Examples 1 to 4 and 11) to which the antimony cationic polymerization initiators (B2) and (B3) were added Nos. 12 to 12 have high exothermic peak temperatures or no exothermic peaks were detected, and it was found that the curability was low. It is recognized that if the exothermic peak temperature is different by about 10° C., the curability is greatly different.

Furthermore, the epoxy resin compositions (Comparative Examples 6 to 7) obtained by adding the antimony cationic polymerization initiators (B2) and (B3) to the bisphenol A type epoxy resin (A5) showed a plurality of exothermic peak temperatures. Further, the epoxy resin compositions (Comparative Examples 9 to 10) obtained by adding the antimony cationic polymerization initiators (B2) and (B3) to the epoxy resin (A6) in which the terminal phenolic hydroxyl group was glycidyl etherified were all It gelled and solidified. Furthermore, the epoxy resin compositions (Comparative Examples 14 to 15 and 17 to 18) obtained by adding the antimony-based cationic polymerization initiators (B2) and (B3) to the 9,9-bisarylfluorene type epoxy resins (A8) and (A9) were prepared. , Gelled and solidified, or no exothermic peak was detected, and it was found that the curability was low. A composition having a plurality of exothermic peak temperatures does not yet completely cure even when heated at a low exothermic peak temperature, and thus needs to be heated at a high exothermic peak temperature. Therefore, the curing operation is complicated for the composition having a plurality of exothermic peak temperatures.

On the other hand, when the boron-based cationic polymerization initiator (B1) is added to the epoxy resin (A1) (A2) (A3) (A4) (A7) of the alkylene oxide adduct, the composition has high storage stability, Almost no thickening occurred after 1 week (Examples 1 to 4), or the degree of thickening was small even when stored under high temperature conditions, and it was usable for 3 days without thickening (Example 5). ). Moreover, even if the amount of the cationic polymerization initiator (B1) added was small, the exothermic peak temperature was low and high curability (low temperature curability) was exhibited. Furthermore, it showed a single exothermic peak temperature. In particular, the 9,9-bisarylfluorene type epoxy resins (A1)(A2)(A3)(A7) had a high refractive index and high heat resistance even though they were alkylene oxide adducts.

The epoxy resin composition (or a cured product thereof) of the present invention has excellent properties such as heat resistance and chemical resistance, as well as optical properties such as transparency, and excellent properties such as adhesion. Therefore, for example, an insulating material such as an insulating material between layers of an electronic component, a laminated material such as a laminated board for a printed circuit board (copper-clad laminated board, etc.), a sealant (semiconductor sealant, etc.), an adhesive, an adhesive , Ink (printing ink, etc.), paint, coating agent, optical material (transparent material) [for example, lens (reflow lens, pickup lens, microlens, etc.), polarizing film, antireflection film, touch panel film, flexible substrate film , A film for a display, an optical fiber, an optical waveguide, a hologram and a coating agent for these optical members], a film for a fuel cell and the like (a wide range of applications for electric/electronic materials, optical materials, etc.). In particular, an epoxy resin having a fluorene skeleton has high heat resistance and high refractive index even if it has an alkylene oxide chain. Therefore, the epoxy resin having a fluorene skeleton can be used in a wide range of insulating materials, laminated materials such as laminated plates, sealing agents, adhesives, paints, coating agents, optical materials, and coating agents for optical members.

Claims (6)

A resin composition comprising an epoxy resin and a cationic polymerization initiator, wherein the terminal is represented by the following formula (1)

(In the formula, R ¹ represents an alkylene group, R ² represents a hydrogen atom or a methyl group, and n represents an integer of 1 to 30.)
An epoxy resin having an oxirane ring-containing group represented by, and an onium salt containing a boron-based anion as the polymerization initiator ,
The epoxy resin contains a compound represented by the following formula (1a) or a multimer thereof:

(In the formula, ring Z is an arene ring, R ^1a and R ^1b are each independently an alkylene group, R ² is a hydrogen atom or a methyl group, and R ³ and R ⁵ are each independently a substituent. , K is an integer of 0 to 4, n1 and n2 are each an integer of 1 to 30, p is an integer of 0 or 1 or more, and q is an integer of 1 or more.)
An epoxy resin composition in which the onium salt contains a boron-based cationic polymerization initiator represented by the following formula (2) .

(In the formula, R ¹¹ represents an alkyl group, an alkenyl group, an alkynyl group, an aryl group which may have a substituent, an aralkyl group which may have a substituent, and R ¹² represents an alkyl group, a substituent Represents an optionally substituted aryl group, R ¹³ represents a hydrogen atom, a halogen atom, an alkyl group, a formyl group, a hydroxyl group, an alkoxy group or an acyloxy group, and R ¹⁴ represents a hydrogen atom, a halogen atom or an alkyl group. X is a fluorine atom or a pentafluorophenyl group.) In the formula (1a), the ring Z is a benzene ring, a naphthalene ring or a biphenyl ring, R ^1a and R ^1b are each independently a linear or branched C _2-6 alkyl group, and an average value of n1+n2. Is 2 to 15, R ² is a hydrogen atom, k and p are 0, and q is 1. The epoxy resin composition according to claim 1 . Onium salts is represented by the following formula (2a) or (2b) an epoxy resin composition according to any one of claims 1 or 2 including a boron-based cationic polymerization initiator represented by.

^{(Wherein, R 11a} is optionally _{C 1-4} alkyl _{group, C 1-4} alkyl optionally substituted _{C 6-12} also be an aryl group with a _group, substituted by _{C 1-4} alkyl groups _{C 6- 12} aryl- _C1-4 alkyl group is shown, ^R12a shows _C1-4 alkyl group, _C6-12 aryl group which may be substituted by the _C1-4 alkyl group, ^R13a is a hydrogen atom, C _1-4 alkyl _{group, C 1-4} alkyl - carbonyl _{group, C 6-12} aryl - indicates a carbonyl ^{group, R 14} represents a hydrogen atom, a halogen atom or a _{C 1-4} alkyl group;
R ^11b represents a hydrogen atom or a C _1-4 alkyl group, R ^12b represents a C _1-4 alkyl group, R ^13b represents a hydrogen atom, a C _1-4 alkyl group, a C _1-4 alkyl-carbonyl group) The epoxy resin composition according to any one of claims 1 to 3, a proportion of the cationic polymerization initiator 0.01 to 10 parts by weight per 100 parts by weight of the epoxy resin. An epoxy resin composition comprising the epoxy resin according to claim 1 and 0.05 to 0.3 part by weight of the cationic polymerization initiator according to claim 1 with respect to 100 parts by weight of the epoxy resin. Cured epoxy resin composition is cured according to any one of claims 1-5.