JP6251557B2 - Compound, thermosetting resin composition, and thermosetting sheet - Google Patents

Description

  The present invention relates to a thermosetting resin composition, a thermosetting sheet, and a novel compound that can be used for them.

  In recent years, the cost reduction of electronic parts or electronic substrate materials has been remarkable, and member design using inexpensive resin as a material has been promoted. In addition, display-related materials are still required to be light and thin, and the use of thinner and cheaper members is indispensable. For this reason, the members are inevitably inferior in heat resistance, and the adhesive for joining the members is required to be able to be cured at a lower temperature.

The use of cationic polymerization is widely known as a technique for performing epoxy resin-based thermosetting at low temperatures.
For example, Patent Document 1 discloses that a sulfonium salt using antimony hexafluoride, phosphorus hexafluoride or the like as a counter anion is useful as a cation curing catalyst for an epoxy resin. In particular, sulfonium salts using antimony hexafluoride are commercially available as low-temperature curing catalysts.
Patent Document 2 discloses a cation curing catalyst using a tetrakis (pentafluorophenyl) borate anion having an activity equivalent to that of antimony hexafluoride.
Although these cationic curing catalysts have low-temperature curing activity, there is a problem that the storage stability when blended with an epoxy resin is extremely insufficient as it is.

In order to solve this problem, Patent Document 3 discloses a technique of adding a specific iron aromatic compound salt or a specific onium salt. Patent Document 4 discloses a technique for adding a specific phosphine oxide derivative.
However, although these techniques improve the storage stability, the low temperature curing activity of the cation curing catalyst is remarkably lowered, so that there is a problem that it is insufficient for compatibility with low temperature curing.

Patent Documents 5 to 7 disclose that an ammonium salt compound can be contained in the thermosetting resin composition for the purpose of accelerating curing.
However, these techniques cannot achieve both low-temperature curability and storage stability.

  Accordingly, it is possible to provide a thermosetting resin composition that can be cured at a low temperature in a short time and that can ensure storage stability before curing, a thermosetting sheet, and a novel compound that can be used for them and is useful as a stabilizer. Is currently required.

Japanese Patent Laid-Open No. 2-1470 JP 9-176112 A Japanese Patent Laid-Open No. 5-5006 Japanese Patent No. 3817620 JP 2013-91687 A JP 2011-132416 A JP 2013-185013 A

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, the present invention is a thermosetting resin composition that can be cured at a low temperature and in a short time and that can ensure storage stability before curing, a thermosetting sheet, and a thermosetting resin composition that can be used for them and is useful as a stabilizer. The object is to provide new compounds.

Means for solving the problems are as follows. That is,
<1> Contains a cationic curing component, a cationic curing agent, and a stabilizer,
The stabilizer is an ammonium salt;
The thermosetting resin composition is characterized in that pKa of an anionic conjugate acid in the ammonium salt at 25 ° C. in water is −1 or more.
<2> The thermosetting resin composition according to <1>, wherein the ammonium salt is a compound represented by any one of the following general formula (1) and the following general formula (2).
However, in said general formula (1), R < ¹ > -R < ⁴ > is respectively independently a C1-C4 alkyl group, a C3-C8 cycloalkyl group, a substituted or unsubstituted aryl group, and It represents either a substituted or unsubstituted aralkyl group. X ⁻ represents an anion.
However, In the general formula (2), ^{R 1} represents an alkyl group having 1 to 4 carbon ^atoms, R 2 to R ⁶ are each independently a hydrogen atom, and alkyl group having 1 to 4 carbon atoms Represents either. Independently, R ² and R ³ , R ³ and R ⁴ , R ⁴ and R ⁵ , and R ⁵ and R ⁶ may be combined to form an aromatic ring. X ⁻ represents an anion.
<3> The thermosetting resin composition according to <2>, wherein X ⁻ in the general formula (1) and the general formula (2) is an anion of a carboxylic acid.
<4> In the general formula (1) and the general formula (2), X ⁻ is any one of anions of benzoic acids, naphthalenecarboxylic acids, diphenylacetic acid anion, trifluoroacetic acid anion, and 2-ethylhexanoic acid anion. The thermosetting resin composition according to any one of <2> to <3>.
<5> The thermosetting resin composition according to any one of <1> to <4>, wherein the cationic curing component is an epoxy compound.
<6> The thermosetting resin composition according to any one of <1> to <5>, wherein the cationic curing agent is a sulfonium borate complex represented by the following general formula (3).
In the general formula (3), Y ⁺ represents a sulfonium cation, and Z represents a halogen atom.
<7> The thermosetting resin composition according to <6>, wherein Y ⁺ in the general formula (3) is a sulfonium cation represented by the following general formula (4).
In the general formula (4), R ¹¹ represents an aralkyl group, R ¹² represents an optionally branched alkyl group having 1 to 4 carbon atoms, and m is an integer of 1 to 3.
<8> The thermosetting resin composition according to any one of <1> to <7>, further including a phenoxy resin.
<9> A thermosetting sheet comprising the thermosetting resin composition according to any one of <1> to <8>.
<10> A compound represented by any one of the following general formula (1) and the following general formula (2).
In the general formula ^(1), R 1 ~R ⁴ are each independently an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, an unsubstituted aryl group, and substituted or It represents one of unsubstituted aralkyl groups. X ⁻ represents an anion having a pKa of −1 or more at 25 ° C. in a conjugate acid in water.
However, In the general formula (2), ^{R 1} represents an alkyl group having 1 to 4 carbon ^atoms, R 2 to R ⁶ are each independently a hydrogen atom, and alkyl group having 1 to 4 carbon atoms Represents either. Independently, R ² and R ³ , R ³ and R ⁴ , R ⁴ and R ⁵ , and R ⁵ and R ⁶ may be combined to form an aromatic ring. X ⁻ represents an anion having a pKa of −1 or more at 25 ° C. in a conjugate acid in water.
<11> In the general formula (1), R ¹ and R ² each independently represents an alkyl group having 1 to 4 carbon atoms, R ³ represents an unsubstituted aryl group, and R ⁴ represents a substituted group. Or it is a compound as described in said <10> which represents an unsubstituted aralkyl group.
<12> In the general formula (1) and the general formula (2), X ⁻ is any one of anions of benzoic acids, naphthalenecarboxylic acids, diphenylacetate anion, trifluoroacetate anion, and 2-ethylhexanoate anion. The compound according to any one of <10> to <11>.

  According to the present invention, a thermosetting resin composition that can solve the above-described problems and can achieve the above-described object, can be cured at a low temperature in a short time, and can ensure storage stability before curing. And a thermosetting sheet, and a novel compound usable for them and useful as a stabilizer can be provided.

(Thermosetting resin composition)
The thermosetting resin composition of the present invention contains at least a cationic curing component, a cationic curing agent, and a stabilizer, preferably contains a film-forming resin, and further contains other components as necessary. To do.

<Cationic curing component>
The cationic curing component is not particularly limited as long as it is a component that is cured by the action of the cationic curing agent, and can be appropriately selected according to the purpose. For example, an epoxy compound, a vinyl ether compound, an oxetane compound, and Examples thereof include cyclic ether compounds. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the epoxy compound include bisphenol type epoxy resin, polyglycidyl ether, polyglycidyl ester, aromatic epoxy compound, alicyclic epoxy compound, novolac type epoxy compound, glycidyl amine type epoxy compound, glycidyl ester type epoxy compound, biphenyl. Examples thereof include diglycidyl ether, triglycidyl isocyanurate, polyglycidyl methacrylate, and a copolymer of glycidyl methacrylate and a vinyl monomer copolymerizable with the glycidyl methacrylate.

  Examples of the alicyclic epoxy resin include a cyclohexene oxide-containing compound and a cyclopentene oxide-containing compound.

  Examples of the vinyl ether compound include alkyl vinyl ether compounds, alkenyl vinyl ether compounds, alkynyl vinyl ether compounds, and aryl vinyl ether compounds.

  Examples of the oxetane compound include oxetane alcohols, aliphatic oxetane compounds, and aromatic oxetane compounds.

  The content of the cationic curing component in the thermosetting resin composition is not particularly limited and may be appropriately selected depending on the purpose, but with respect to the nonvolatile content of the thermosetting resin composition, 10 mass%-98 mass% are preferable, 20 mass%-90 mass% are more preferable, and 30 mass%-60 mass% are especially preferable.

<Cationic curing agent>
The cationic curing agent is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a sulfonium salt compound described in JP-A-2-1470, and JP-A-9-176112 Examples include sulfonium borate complexes, sulfonium borate complexes described in JP-A-2008-308596, and sulfonium borate complexes described in JP-A-2008-303167.

Among these, a sulfonium borate complex represented by the following general formula (3) is preferable from the viewpoint of excellent low-temperature curability. In addition, a compound having antimony hexafluoride or tetrakis (pentafluorophenyl) borate as an anion is preferable because cationic curing activity can be obtained. However, since the curing agent having an antimony hexafluoride anion generates a large amount of fluorine ions at the time of thermal curing, there is a problem that the metal part is corroded when used for joining a member having a metal part. In this respect, a sulfonium salt having a tetrakis (pentafluorophenyl) borate anion is more preferable.
In the general formula (3), Y ⁺ represents a sulfonium cation, and Z represents a halogen atom.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Y ⁺ in the general formula (3) is a sulfonium cation represented by the following general formula (4). The raw material is easily available, the synthesis is easy, and the crystals are easily taken out and stable at room temperature. It is preferable from the point.
In the general formula (4), R ¹¹ represents an aralkyl group, R ¹² represents an optionally branched alkyl group having 1 to 4 carbon atoms, and m is an integer of 1 to 3.

Examples of the aralkyl group of R ¹¹ include an aralkyl group having 7 to 20 carbon atoms.
Examples of the aryl group in the aralkyl group include an aromatic hydrocarbon group. Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, and an anthracenyl group.
Examples of the alkylene group in the aralkyl group include a methylene group and an ethylene group.
Examples of the aralkyl group include a benzyl group, an o-methylbenzyl group, a (1-naphthyl) methyl group, a pyridylmethyl group, and an anthracenylmethyl group.
Among these, a (1-naphthyl) methyl group is preferable in terms of good quick curability and availability.

Examples of the optionally branched alkyl group having 1 to 4 carbon atoms for R ¹² include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, and a tert-butyl group. Can be mentioned. Among these, a methyl group is preferable in terms of good quick curability and availability.

When R ¹² is a methyl group, R ¹¹ is preferably not a benzyl group.

M representing the number of hydroxyl groups of the phenyl group bonded to the sulfonium residue is an integer of 1 to 3.
As such a phenyl group, when m is 1, a 4-hydroxyphenyl group, a 2-hydroxyphenyl group, a 3-hydroxyphenyl group and the like can be mentioned. When m is 2, 2,4-dihydroxyphenyl group, 2,6-dihydroxyphenyl group, 3,5-dihydroxyphenyl group, 2,3-dihydroxyphenyl group and the like can be mentioned. When m is 3, 2,4,6-trihydroxyphenyl group, 2,4,5-trihydroxyphenyl group, 2,3,4-trihydroxyphenyl group and the like can be mentioned. Among these, a 4-hydroxyphenyl group is preferable in terms of good quick curability and availability.

Examples of the sulfonium borate complex as the cationic curing agent include the following sulfonium borate complexes.

  The sulfonium borate complex represented by the general formula (3) can be produced, for example, by the production method described in JP-A-2008-303167.

  The content of the cationic curing agent in the thermosetting resin composition is not particularly limited and can be appropriately selected according to the purpose.For the nonvolatile content of the thermosetting resin composition, 0.5 mass%-20 mass% are preferable, and 2 mass%-15 mass% are more preferable.

<Stabilizer>
The stabilizer is an ammonium salt.
The pKa of the anionic conjugate acid in the ammonium salt at 25 ° C. in water is −1 or more.
The stabilizer ensures the preservability of the thermosetting resin composition, and further, when the pKa of the conjugate acid of the counter anion is −1 or more, it is possible to achieve both preservability and low temperature curability.
There is no restriction | limiting in particular as an upper limit of the said pKa, Although it can select suitably according to the objective, It is preferable that the said pKa is 9 or less.

Examples of the conjugate acid having a pKa of −1 or more include p. Of Electrochemical Handbook 5th Edition (Electrical Society of Japan: Maruzen). 102-p. The pKa data in water can be referred to from 104 or the following URL address.
http: // www. chem. wsc. edu / areas / organic / index-chem. htm

The ammonium salt is a compound represented by any one of the following general formula (1) and the following general formula (2), the raw materials are easily available, the synthesis is easy, and the crystals are easily taken out at room temperature. It is preferable because it is stable.
However, in said general formula (1), R < ¹ > -R < ⁴ > is respectively independently a C1-C4 alkyl group, a C3-C8 cycloalkyl group, a substituted or unsubstituted aryl group, and It represents either a substituted or unsubstituted aralkyl group. X ⁻ represents an anion (an anion having a pKa of −1 or more at 25 ° C. in a conjugate acid in water).
However, In the general formula (2), ^{R 1} represents an alkyl group having 1 to 4 carbon ^atoms, R 2 to R ⁶ are each independently a hydrogen atom, and alkyl group having 1 to 4 carbon atoms Represents either. Independently, R ² and R ³ , R ³ and R ⁴ , R ⁴ and R ⁵ , and R ⁵ and R ⁶ may be combined to form an aromatic ring. X ⁻ represents an anion (an anion having a pKa of −1 or more at 25 ° C. in a conjugate acid in water).

Examples of the alkyl group having 1 to ⁴ carbon atoms of R ^{1 to} R ⁴ in the general formula (1) include, for example, methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, tert- A butyl group etc. are mentioned. Among these, a methyl group is preferable in terms of thermal stability.

Examples of the cycloalkyl group having 3 to 8 carbon atoms of R ^{1 to} R ⁴ in the general formula (1) include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Can be mentioned. Among these, a cyclohexyl group is preferable in terms of easy availability of raw materials.

Examples of the substituted or unsubstituted aryl group of R ^{1 to} R ⁴ in the general formula (1) include an unsubstituted aromatic hydrocarbon group and a substituted aromatic hydrocarbon group. Examples of the unsubstituted aromatic hydrocarbon group include a phenyl group and a naphthyl group. Examples of the substituted aromatic hydrocarbon group include a substituted phenyl group and a substituted naphthyl group. Examples of the substituted phenyl group include an alkyl-substituted phenyl group. Examples of the alkyl substituent in the alkyl-substituted phenyl group include an alkyl group having 1 to 4 carbon atoms. Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, and a tert-butyl group.

The substituted or unsubstituted aralkyl group of said R ¹ to R ⁴ in the general formula (1) include, for example, an aralkyl group having 7 to 15 carbon atoms.
Examples of the aryl group in the aralkyl group include an aromatic hydrocarbon group. Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, and an anthracenyl group. Examples of the substituent include an alkyl group having 1 to 4 carbon atoms. Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, and a tert-butyl group.
Examples of the alkylene group in the aralkyl group include a methylene group and an ethylene group.
Examples of the aralkyl group include benzyl group, o-methylbenzyl group, p-methylbenzyl group, 2,5-dimethylbenzyl group, (1-naphthyl) methyl group, and phenethyl group.

In the general formula (1), R ¹ and R ² each independently represents an alkyl group having 1 to 4 carbon atoms, R ³ represents a substituted or unsubstituted aryl group, and R ⁴ represents a substituted group. Alternatively, it is preferable to represent an unsubstituted aralkyl group in terms of easy production as a crystalline product and simple synthesis.

In the general formula (1), it is preferable that R ^{1 to} R ⁴ each independently represent an alkyl group having 1 to 4 carbon atoms from the viewpoint that inexpensive raw materials can be used.

Examples of the alkyl group having 1 to 4 carbon atoms of R ¹ in the general formula (2) include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, and a tert-butyl group. Is mentioned. Among these, a methyl group and an ethyl group are preferable in terms of easy availability of raw materials.

Examples of the alkyl group having 1 to 4 carbon atoms of R ^{2 to} R ⁶ in the general formula (2) include, for example, methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, tert- A butyl group etc. are mentioned.

In the general formula (2), examples of the aromatic ring formed by R ² and R ³ , R ³ and R ⁴ , R ⁴ and R ⁵ , and R ⁵ and R ⁶ include a benzene ring.

Examples of the cation of the ammonium salt represented by the general formula (1) include cations represented by the following structural formulas (1-1) to (1-4).

Examples of the cation of the ammonium salt represented by the general formula (2) include cations represented by the following structural formulas (2-1) to (2-5).

<< X < ^- > in General Formula (1) and General Formula (2) >>
Wherein X in the general formula (1) and the general formula (2) ^- is an anion having a pKa of -1 or more in water 25 ° C. conjugate acid.

As said X < ^- >, a carboxylate anion is preferable from the point that a raw material is easy to obtain, and the point which is easy to synthesize | combine.

Examples of the carboxylate anion include anions represented by the following general formula (5).
In the general formula (5), R ²¹ represents a hydrocarbon group.

  The hydrocarbon group may have a halogen atom. Examples of the halogen atom include a fluorine atom and a chlorine atom.

  Examples of the hydrocarbon group include a hydrocarbon group having a cyclic structure.

  Examples of the hydrocarbon group having a cyclic structure include a hydrocarbon group having an aromatic group and a hydrocarbon group having an alicyclic structure.

  There is no restriction | limiting in particular as carbon number of the said hydrocarbon group, Although it can select suitably according to the objective, 1-15 are preferable and 6-13 are more preferable.

  Examples of the carboxylic acid include saturated fatty acids, unsaturated fatty acids, carboxylic acids having an aromatic ring, carboxylic acids having an alicyclic structure, acrylic acid, and trifluoroacetic acid.

Examples of the saturated fatty acid include acetic acid, propionic acid, myristic acid, stearic acid, 2-ethylhexanoic acid and the like.
Examples of the unsaturated fatty acid include oleic acid and linoleic acid.
Examples of the carboxylic acid having an alicyclic structure include 1-adamantanecarboxylic acid and cyclohexanecarboxylic acid.
Examples of the carboxylic acid having an aromatic ring include benzoic acid, 2-methylbenzenecarboxylic acid, 2-phenylbenzenecarboxylic acid, 2,6-dimethylbenzenecarboxylic acid, and 2-hydroxybenzenecarboxylic acid. Substituted benzoic acids (benzoic acid optionally having a substituent); 1-naphthalenecarboxylic acid, 2-naphthalenecarboxylic acid, 2-hydroxy-1-naphthalenecarboxylic acid, 3-hydroxy-2-naphthalenecarboxylic acid, etc. Naphthalene carboxylic acids; naphthalene acetic acid, phenylpropionic acid, diphenylacetic acid, triphenylacetic acid and the like.

  The carboxylic acid anion is preferably a benzoic acid anion, a naphthalenecarboxylic acid anion, a diphenylacetic acid anion, a trifluoroacetic acid anion, or a 2-ethylhexanoic acid anion from the viewpoint that crystals are easily obtained.

Examples of the stabilizer include the following stabilizers.

  There is no restriction | limiting in particular as content of the said stabilizer in the said thermosetting resin composition, Although it can select suitably according to the objective, 1 mol%-10 mol% are preferable with respect to the said cationic hardening | curing agent. 2 mol% to 5 mol% is more preferable. If the content is less than 1 mol%, the stabilizing effect may not be sufficiently exhibited. When the content exceeds 10 mol%, it may be difficult to perform curing at a low temperature in a short time.

<Film forming resin>
The film-forming resin is not particularly limited and can be appropriately selected depending on the purpose. For example, polyacrylic resin, phenoxy resin, polyester resin, polyurethane resin, polyester urethane resin, polyvinyl butyral resin, polyvinyl formal resin, Examples thereof include polyamide resin and polyimide resin. These may be used individually by 1 type and may use 2 or more types together. Among these, a phenoxy resin is particularly preferable from the viewpoint of film formability and processability.

Examples of the phenoxy resin include those obtained by reacting a bifunctional phenol with epichlorohydrin to increase the molecular weight, or a resin obtained by polyaddition of a bifunctional epoxy resin and a bifunctional phenol.
Examples of the bifunctional epoxy resin used include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol S type epoxy resin, biphenyl diglycidyl ether, and methyl-substituted biphenyl diglycidyl ether. It is done.
Examples of the bifunctional phenols include hydroquinones, bisphenol A, bisphenol F, bisphenol AD, bisphenol S, bisphenol fluorene, methyl-substituted bisphenol fluorene, bisphenols such as dihydroxybiphenyl and methyl-substituted dihydroxybiphenyl.

  There is no restriction | limiting in particular as content of the said film formation resin in the said thermosetting resin composition, Although it can select suitably according to the objective, It is 10 with respect to the non volatile matter of the said thermosetting resin composition. % By mass to 90% by mass is preferable, 20% by mass to 80% by mass is more preferable, and 30% by mass to 60% by mass is particularly preferable.

<Other ingredients>
The other components are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include thixotropic agents, fillers, leveling agents, antioxidants, colorants, conductivity-imparting agents, and adhesion-imparting agents. Is mentioned.

(Thermosetting sheet)
The said thermosetting sheet | seat of this invention contains the said thermosetting resin composition of this invention, and also contains another component as needed.

The thermosetting sheet is formed, for example, by forming a thermosetting adhesive layer made of the thermosetting resin composition on a base film (peeling base). Examples of the base film include a polyethylene terephthalate film and a polyimide film.
From the viewpoints of storage properties, handling properties during use, and the like, the thermosetting sheet is obtained by applying the thermosetting resin composition to a base film that is peel-treated with silicone or the like as necessary for a polyethylene terephthalate film, a polyimide film, or the like. It is preferable that the thermosetting adhesive layer made of is formed with an average thickness of 10 μm to 50 μm.

  The thermosetting resin composition and the thermosetting sheet can be preferably applied to the field of electronic components. In particular, the thermosetting sheet adheres and fixes a terminal portion of a flexible printed wiring board and a reinforcing sheet having a thickness of 50 μm to 2 mm such as polyethylene terephthalate, polyimide, glass epoxy, stainless steel, and aluminum for lining the same. Therefore, the terminal portion of the flexible printed wiring board and the reinforcing sheet can be bonded and fixed with the thermosetting material of the thermosetting adhesive layer excluding the base film of the thermosetting sheet of the present invention. Thus, a reinforced flexible printed wiring board is obtained.

(Compound)
The compound of this invention is represented by either the following general formula (1) or the following general formula (2). The said compound is useful as a stabilizer which improves the storage stability of the thermosetting resin composition cation-cured at low temperature.
In the general formula ^(1), R 1 ~R ⁴ are each independently an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, an unsubstituted aryl group, and substituted or It represents one of unsubstituted aralkyl groups. X ⁻ represents an anion having a pKa of −1 or more at 25 ° C. in a conjugate acid in water.
However, In the general formula (2), ^{R 1} represents an alkyl group having 1 to 4 carbon ^atoms, R 2 to R ⁶ are each independently a hydrogen atom, and alkyl group having 1 to 4 carbon atoms Represents either. Independently, R ² and R ³ , R ³ and R ⁴ , R ⁴ and R ⁵ , and R ⁵ and R ⁶ may be combined to form an aromatic ring. X ⁻ represents an anion having a pKa of −1 or more at 25 ° C. in a conjugate acid in water.

Examples of the alkyl group having 1 to ⁴ carbon atoms of R ^{1 to} R ⁴ in the general formula (1) include, for example, methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, tert- A butyl group etc. are mentioned. Among these, a methyl group is preferable in terms of thermal stability.

Examples of the cycloalkyl group having 3 to 8 carbon atoms of R ^{1 to} R ⁴ in the general formula (1) include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Can be mentioned. Among these, a cyclohexyl group is preferable in terms of easy availability of raw materials.

Examples of the unsubstituted aryl group represented by R ^{1 to} R ⁴ in the general formula (1) include a phenyl group and a naphthyl group.

The substituted or unsubstituted aralkyl group of said R ¹ to R ⁴ in the general formula (1) include, for example, an aralkyl group having 7 to 15 carbon atoms.
Examples of the aryl group in the aralkyl group include an aromatic hydrocarbon group. Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, and an anthracenyl group. Examples of the substituent include an alkyl group having 1 to 4 carbon atoms. Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, and a tert-butyl group.
Examples of the alkylene group in the aralkyl group include a methylene group and an ethylene group.
Examples of the aralkyl group include benzyl group, o-methylbenzyl group, p-methylbenzyl group, 2,5-dimethylbenzyl group, (1-naphthyl) methyl group, and phenethyl group.

In the general formula (1), R ¹ and R ² each independently represents an alkyl group having 1 to 4 carbon atoms, R ³ represents an unsubstituted aryl group, and R ⁴ represents substituted or unsubstituted. It is preferable to represent a substituted aralkyl group in terms of easy production as a crystalline product and simple synthesis.

In the general formula (1), it is preferable that R ^{1 to} R ⁴ each independently represent an alkyl group having 1 to 4 carbon atoms from the viewpoint that inexpensive raw materials can be used.

Examples of the alkyl group having 1 to 4 carbon atoms of R ¹ in the general formula (2) include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, and a tert-butyl group. Is mentioned. Among these, a methyl group and an ethyl group are preferable in terms of easy availability of raw materials.

Examples of the alkyl group having 1 to 4 carbon atoms of R ^{2 to} R ⁶ in the general formula (2) include, for example, methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, tert- A butyl group etc. are mentioned.

In the general formula (2), examples of the aromatic ring formed by R ² and R ³ , R ³ and R ⁴ , R ⁴ and R ⁵ , and R ⁵ and R ⁶ include a benzene ring.

Examples of the cation of the ammonium salt represented by the general formula (1) include cations represented by the following structural formulas (1-1), (1-3), and (1-4).

Examples of the cation of the ammonium salt represented by the general formula (2) include cations represented by the following structural formulas (2-1) to (2-5).

<< X < ^- > in General Formula (1) and General Formula (2) >>
Wherein X in the general formula (1) and the general formula (2) ^- is an anion having a pKa of -1 or more in water 25 ° C. conjugate acid.
There is no restriction | limiting in particular as an upper limit of the said pKa, Although it can select suitably according to the objective, It is preferable that the said pKa is 9 or less.

As said X < ^- >, a carboxylate anion is preferable from the point that a raw material is easy to obtain, and the point which is easy to synthesize | combine.

Examples of the carboxylate anion include anions represented by the following general formula (5).
In the general formula (5), R ²¹ represents a hydrocarbon group.

  The hydrocarbon group may have a halogen atom. Examples of the halogen atom include a fluorine atom and a chlorine atom.

  Examples of the hydrocarbon group include a hydrocarbon group having a cyclic structure.

  Examples of the hydrocarbon group having a cyclic structure include a hydrocarbon group having an aromatic group and a hydrocarbon group having an alicyclic structure.

  There is no restriction | limiting in particular as carbon number of the said hydrocarbon group, Although it can select suitably according to the objective, 1-15 are preferable and 6-13 are more preferable.

  Examples of the carboxylic acid include saturated fatty acids, unsaturated fatty acids, carboxylic acids having an aromatic ring, carboxylic acids having an alicyclic structure, acrylic acid, and trifluoroacetic acid.

Examples of the saturated fatty acid include acetic acid, propionic acid, myristic acid, stearic acid, 2-ethylhexanoic acid and the like.
Examples of the unsaturated fatty acid include oleic acid and linoleic acid.
Examples of the carboxylic acid having an alicyclic structure include 1-adamantanecarboxylic acid and cyclohexanecarboxylic acid.
Examples of the carboxylic acid having an aromatic ring include benzoic acid, 2-methylbenzenecarboxylic acid, 2-phenylbenzenecarboxylic acid, 2,6-dimethylbenzenecarboxylic acid, and 2-hydroxybenzenecarboxylic acid. Substituted benzoic acids (benzoic acid optionally having a substituent); 1-naphthalenecarboxylic acid, 2-naphthalenecarboxylic acid, 2-hydroxy-1-naphthalenecarboxylic acid, 3-hydroxy-2-naphthalenecarboxylic acid, etc. Naphthalene carboxylic acids; naphthalene acetic acid, phenylpropionic acid, diphenylacetic acid, triphenylacetic acid and the like.

  The carboxylic acid anion is preferably a benzoic acid anion, a naphthalenecarboxylic acid anion, a diphenylacetic acid anion, a trifluoroacetic acid anion, or a 2-ethylhexanoic acid anion from the viewpoint that crystals are easily obtained.

Examples of the compound include the following stabilizers.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Synthesis Example 1)
<Synthesis of silver diphenyl acetate>
Sodium hydroxide 10.0 g (0.25 mol) and 1,000 g of methanol were placed in a 5 L three-necked flask equipped with a stirrer and a thermometer and stirred, and then 53.05 g of diphenylacetic acid (manufactured by Tokyo Chemical Industry Co., Ltd.). (0.25 mol) was added and stirred at room temperature until there was no solid content. Thereto, 849.35 g (0.25 mol as silver nitrate) of a 5% by mass aqueous solution of silver nitrate (manufactured by Wako Pure Chemical Industries, Ltd.) separately prepared was added dropwise over 10 minutes while stirring the flask at room temperature. A white precipitate was formed immediately after the dropping. After completion of the dropwise addition, the mixture was further stirred for 30 minutes, and then the precipitate was separated by filtration, washed with methanol, and dried under reduced pressure for 24 hours to obtain 76.9 g of white crystals of silver diphenylacetate (yield 96.4%). )

(Synthesis Example 2)
<Synthesis of silver 1-naphthalenecarboxylate>
In Synthesis Example 1, except that diphenylacetic acid was changed to 43.05 g (0.25 mol) of 1-naphthalenecarboxylic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), in the same manner as in Example 1, silver 1-naphthalenecarboxylate 66.1 g (yield 94.7%) of white crystals were obtained.

Example 1
<Synthesis of Ammonium Salt (Stabilizer) A1>
A 100 mL three-necked flask equipped with a stirrer was charged with 3.000 g (0.01748 mol) of trimethylphenylammonium chloride (manufactured by Tokyo Chemical Industry Co., Ltd.), 30 g of acetonitrile and 10 g of methanol and stirred at room temperature to obtain a uniform solution. After making the flask light-shielded, 5.577 g (0.01748 mol) of silver diphenylacetate synthesized in Synthesis Example 1 was added thereto and further stirred for 1 hour. After stirring, filtering was performed under light shielding to remove the precipitated silver chloride, and the filtrate was concentrated under reduced pressure to obtain a transparent viscous liquid. This was further dried under reduced pressure for 24 hours, solidified, washed with ethyl acetate, filtered, and dried again under reduced pressure for 24 hours, whereby the ammonium salt (stabilizer) A1 represented by the following structural formula (A1) 5.758 g (yield 94.8%) of white crystals were obtained.

(Example 2)
<Synthesis of Ammonium Salt (Stabilizer) A2>
In Example 1, except that silver diphenylacetate was changed to 4.877 g (0.01748 mol) of silver 1-naphthalenecarboxylate synthesized in Synthesis Example 2, the following structural formula (A2) was used. 5.169 g (yield 96.2%) of white crystals of the ammonium salt (stabilizer) A2 represented were obtained.

(Example 3)
<Synthesis of ammonium salt (stabilizer) A3>
In Example 1, ammonium represented by the following structural formula (A3) was obtained in the same manner as in Example 1 except that silver diphenyl acetate was changed to 4.002 g (0.01748 mol) of silver benzoate (Merck). 3.850 g (yield 85.6%) of white crystals of salt (stabilizer) A3 was obtained.

Example 4
<Synthesis of ammonium salt (stabilizer) A4>
In Example 1, except that silver diphenyl acetate was changed to 3.860 g (0.01748 mol) of silver trifluoroacetate (Tokyo Chemical Industry Co., Ltd.), the following structural formula (A4) 4.060 g (yield 93.2%) of white crystals of the ammonium salt (stabilizer) A4 represented was obtained.

(Example 5)
<Synthesis of Ammonium Salt (Stabilizer) A5>
In Example 1, except that silver diphenylacetate was changed to 4.283 g (0.01748 mol) of 2-hydroxybenzoic acid silver (silver salicylate, manufactured by Wako Pure Chemical Industries, Ltd.), 4.419 g (yield 92.5%) of white crystals of ammonium salt (stabilizer) A5 represented by the structural formula (A5) was obtained.

(Example 6)
<Synthesis of ammonium salt (stabilizer) A6>
In a 100 mL three-necked flask equipped with a stirrer, a condenser, and a thermometer, 5.0 g (0.03698 mol) of N, N-dimethyl-p-toluidine (manufactured by Tokyo Chemical Industry Co., Ltd.), benzyl chloride (Tokyo Chemical Industry Co., Ltd.) (Company) 5.149 g (0.04068 mol) and methanol 30 g were added, and the mixture was stirred at 50 ° C. for 5 hours to be reacted. After cooling, methanol was distilled off under reduced pressure to obtain a reddish brown viscous liquid. To this, 100 g of ethyl acetate was slowly added with stirring to precipitate white crystals. The crystals were removed by filtration under reduced pressure, washed with ethyl acetate, filtered again under reduced pressure, and further dried under reduced pressure for 24 hours to give white crystals of N-benzyl-N, N-dimethyl-4-methylanilinium chloride. 249 g (yield 85.2%) was obtained.

Next, 1.5 g of the white crystals and 30 g of methanol were placed in a 100 mL three-necked flask equipped with a stirrer, and stirred at room temperature to obtain a uniform solution. After making the flask light-shielded, 1.829 g (0.00573 mol) of silver diphenylacetate synthesized in Synthesis Example 1 was added thereto and further stirred for 1 hour. After stirring, filtering was performed under light shielding to remove the precipitated silver chloride, and the filtrate was concentrated under reduced pressure to obtain a transparent viscous liquid. This was further dried under reduced pressure for 24 hours, solidified, washed with ethyl acetate, filtered, and dried again under reduced pressure for 24 hours, whereby ammonium salt (stabilizer) A6 represented by the following structural formula (A6) was obtained. 2.352 g (yield 93.8%) of white crystals were obtained.

(Example 7)
<Synthesis of ammonium salt (stabilizer) A7>
A 100 mL three-necked flask equipped with a stirrer was charged with 3.0 g (0.08111 mol) of tetraethylammonium chloride (manufactured by Tokyo Chemical Industry Co., Ltd.), 30 g of acetonitrile and 10 g of methanol and stirred at room temperature to obtain a uniform solution. After making the flask light-shielded, 5.778 g (0.08111 mol) of silver diphenylacetate synthesized in Synthesis Example 1 was added thereto and further stirred for 1 hour. After stirring, filtering was performed under light shielding to remove the precipitated silver chloride, and the filtrate was concentrated under reduced pressure to obtain a transparent viscous liquid. This was further dried under reduced pressure for 24 hours, solidified, washed with ethyl acetate, filtered, and dried again under reduced pressure for 24 hours, whereby the ammonium salt (stabilizer) A7 represented by the following structural formula (A7) was obtained. 4.904 g (yield 79.3%) of white crystals were obtained.

(Example 8)
<Synthesis of Ammonium Salt (Stabilizer) A8>
A 100 mL three-necked flask equipped with a stirrer was charged with 3.0 g (0.08111 mol) of tetraethylammonium chloride (manufactured by Tokyo Chemical Industry Co., Ltd.), 30 g of acetonitrile and 10 g of methanol and stirred at room temperature to obtain a uniform solution. After making the flask light-shielded, 4.546 g (0.08111 mol) of silver 2-ethylhexanoate (manufactured by Wako Pure Chemical Industries, Ltd.) was added thereto, and further stirred for 1 hour. After stirring, filtering was performed under light shielding to remove the precipitated silver chloride, and the filtrate was concentrated under reduced pressure to obtain a transparent viscous liquid. This was further washed with hexane, decanted, and again dried under reduced pressure for 24 hours, whereby a transparent viscous liquid of ammonium salt (stabilizer) A8 represented by the following structural formula (A8) 3.734 g (yield) Rate 75.4%).

Example 9
<Synthesis of Ammonium Salt (Stabilizer) A9>
A 100 mL three-necked flask equipped with a stirrer was charged with 3.0 g (0.02315 mol) of 1-methylpyridinium chloride (manufactured by Tokyo Chemical Industry Co., Ltd.), 30 g of acetonitrile, and 10 g of methanol, and stirred at room temperature to obtain a uniform solution. After making the flask light-shielded, 7.388 g (0.02315 mol) of silver diphenylacetate synthesized in Synthesis Example 1 was added thereto, followed by further stirring for 1 hour. After stirring, filtering was performed under light shielding to remove the precipitated silver chloride, and the filtrate was concentrated under reduced pressure to obtain a transparent viscous liquid. This was further dried under reduced pressure for 24 hours, solidified, then washed with ethyl acetate, filtered, and dried again under reduced pressure for 24 hours to obtain an ammonium salt (stabilizer) A9 represented by the following structural formula (A9). 6.391 g (yield 90.4%) of white crystals were obtained.

(Example 10)
<Synthesis of Ammonium Salt (Stabilizer) A10>
In Example 9, except that 1-methylpyridinium chloride was changed to 3.325 g (0.02315 mol) of 1-ethylpyridinium chloride (Tokyo Chemical Industry Co., Ltd.), the following structural formula ( 6.115 g (yield 82.7%) of white crystals of ammonium salt (stabilizer) A10 represented by A10) were obtained.

(Comparative Example 1)
<Synthesis of Ammonium Salt B1>
N, N-dimethylaniline (manufactured by Tokyo Chemical Industry Co., Ltd.) (5.0 g, 0.04126 mol) and toluene (20 g) were placed in a 100 mL three-necked flask equipped with a stirrer, a condenser tube, and a thermometer, and stirred while stirring. The temperature was raised to ° C. Thereto, 5.204 g (0.04126 mol) of dimethyl sulfate (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise and further stirred for 3 hours. Thereafter, the mixture was cooled, filtered under reduced pressure, and dried under reduced pressure for 24 hours to obtain 7.071 g (yield: 69.3%) of white crystals of an ammonium salt B1 represented by the following structural formula (B1).

(Comparative Example 2)
<Synthesis of Ammonium Salt B3>
A 100 mL three-necked flask equipped with a stirrer was charged with 3.0 g (0.01748 mol) of trimethylphenylammonium chloride (manufactured by Tokyo Chemical Industry Co., Ltd.), 30 g of acetonitrile and 10 g of methanol and stirred at room temperature to obtain a uniform solution. After making the flask light-shielded, 3.623 g (0.01748 mol) of silver perchlorate (manufactured by Wako Pure Chemical Industries, Ltd.) was added thereto and further stirred for 1 hour. After stirring, filtering was performed under light shielding to remove the precipitated silver chloride, and the filtrate was concentrated under reduced pressure to obtain a transparent viscous liquid. 2. This was further dried under reduced pressure for 24 hours, solidified, washed with ethyl acetate, filtered, and dried again under reduced pressure for 24 hours, whereby white crystals of an ammonium salt B3 represented by the following structural formula (B3). 637 g (yield 88.3%) was obtained.

(Comparative Example 3)
<Synthesis of Ammonium Salt B4>
In a 100 mL three-necked flask equipped with a stirrer, a condenser tube, and a thermometer, 3.0 g (0.03793 mol) of pyridine and 20 g of toluene were added, and the temperature was raised to 70 ° C. while stirring. Thereto, 4.784 g (0.03793 mol) of dimethyl sulfate (manufactured by Wako Pure Chemical Industries, Ltd.) was dropped, and the mixture was further stirred for 5 hours. Thereafter, the mixture was cooled, filtered under reduced pressure, and dried under reduced pressure for 24 hours to obtain 4.850 g (yield 62.3%) of white crystals of ammonium salt B4 represented by the following structural formula (B4).

(Examples 11 to 25 and Comparative Examples 4 to 10)
Thermosetting resin compositions were prepared according to the formulations shown in Table 1-1 and Table 1-2.
The prepared thermosetting resin composition is coated on release PET (polyethylene terephthalate) that has been subjected to silicone-based mold release treatment, and is dried in a hot-air circulating oven set at 60 ° C. for 5 minutes, thereby thermosetting with an average thickness of 15 μm. Sheet was prepared.
Table 2 shows the pKa values at 25 ° C. of the conjugate acids of the anions of the compounds represented by the structural formulas (1A) to (A10) and (B1) to (B4) in water.

The blending of the phenoxy resin in Table 1-1 and Table 1-2 is the blending amount excluding the solvent, and the unit is parts by mass. The unit of blending the epoxy resin and the cationic curing agent is part by mass. The composition of the stabilizer and structural formulas (B1) to (B4) is mol% with respect to the cationic curing agent.
In addition, each material in Table 1 is as follows.
YP70: manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., bisphenol A / bisphenol F copolymer type phenoxy resin FX-316: manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., bis F type phenoxy resin YL980: manufactured by Mitsubishi Chemical Co., Ltd., bis A type Epoxy resin YL983U: Mitsubishi Chemical Corporation, bis-F type epoxy resin

  In addition, when mix | blending, YP70 and FX-316 used the 45 mass% solid content solution of methyl ethyl ketone. YL980 and YL983U used stock solutions. As the compound represented by the structural formula (1a), a 30% by mass solid content solution of methyl ethyl ketone was used. Moreover, what was melt | dissolved in methanol and was used as the 1 mass% solid content was used for the compound represented by Structural formula (1A)-(A10), (B1)-(B4).

(Evaluation of low-temperature curability and storage stability of thermosetting sheets of Examples 11 to 25 and Comparative Examples 4 to 10)
The initial low-temperature curability and storage stability of the produced thermosetting sheets (average thickness: 15 μm) of Examples 11 to 25 and Comparative Examples 4 to 10 were measured with a differential scanning calorimeter DSC6200 manufactured by SII Nanotechnology. It was evaluated by.
Storage stability was evaluated by calculating the rate of decrease from the calorific value change in DSC before and after standing for 2 weeks in a dark environment of 25 ° C./65% Rh.

As is well known in the art, the exothermic behavior by differential scanning calorimetry reflects the curing reaction behavior of the epoxy resin. Therefore, it can be said that the lower the curing start temperature and the curing end temperature, the lower the curability of the composition.
In the present invention, the low temperature curability was evaluated using as an index the temperature at which 2% of the total heat generation in the DSC chart reaches the curing start temperature and the temperature at which the curing end temperature reaches 95% of the total heat generation in the DSC chart. In either case, the lower temperature has low-temperature curing activity.
Moreover, the amount of change in the amount of heat generated before and after being left reflects the amount of progress of the reaction during being left. It can be said that the smaller the change in calorific value before and after being left, the higher the storage stability. When the epoxy resin is used, specifically, the function as a thermosetting sheet can be maintained by suppressing the amount of change in the heat generation amount before and after being left to 5% or less of the total heat generation.
<Measurement conditions>
Temperature rising rate 10 ° C / min
N ₂ gas 100ml / min
Sample weight about 10mg

  The results are shown in Tables 3-1 and 3-2.

(Evaluation of short-time curability of Examples 11 to 25 and Comparative Examples 4 to 10)
The short-time curability of the produced thermosetting sheets of Examples 11 to 25 and Comparative Examples 4 to 10 (average thickness 15 μm) was confirmed by the following method.
<Evaluation of short-time curability>
1.5 mg of each thermosetting sheet was put into an aluminum container having a diameter of 5 mm for a differential scanning calorimeter DSC6200 manufactured by SII Nano Technology, Inc., and a clamp cover was made to prepare an evaluation sample. After each sample was pressed against the heater plate for 5 seconds, differential scanning calorimetry was performed, and the reaction rate was calculated from the calorific value and the calorific value before pressing. The temperature of the heater plate was 120 ° C and 130 ° C.
<Measurement conditions>
Temperature rising rate 10 ° C / min
N ₂ gas 100ml / min
Sample weight about 1.5mg

  The results are shown in Tables 4-1 and 4-2.

From the results of Table 3-1, Table 3-2, Table 4-1, and Table 4-2, the thermosetting resin compositions and thermosetting sheets of Examples 11 to 25 were added with the stabilizer of the present invention. Compared to Comparative Example 10 in which no heat treatment is performed, the rate of decrease in heat generation before and after being left is sufficiently suppressed, and it can be said that storage stability is achieved.
Furthermore, from the results of Examples 11 to 20 and Comparative Examples 4 to 7, the thermosetting resin composition and the thermosetting sheet of the present invention using the stabilizer of the present invention are comparative examples (structural formula (B1) (B4)) The thermosetting resin composition and thermosetting sheet of (B4)) have a reduced exothermic decrease rate before and after standing, and can be said to have excellent storage stability. Moreover, it turns out that what added the stabilizer of this invention is lower temperature in any temperature of the hardening start and hardening completion | finish. Furthermore, in the evaluation of short-time curability, it can be seen that the reaction rate is high when the stabilizer of the present invention is added.
Moreover, from the results of Examples 11, 21 to 23 and Comparative Examples 4, 8, and 9, the thermosetting resin composition and the thermosetting sheet of the present invention are preserved even when the addition amount of the stabilizer of the present invention is changed. The thermosetting resin composition and the thermosetting sheet of the comparative example are found to be difficult to achieve at the same time.
Further, it can be seen from the pKa value of the conjugate acid of the anion of the stabilizer and comparative compound of the present invention that the effect of the present invention can be obtained when the pKa is -1 or more.
From the above, the usefulness of the present invention was proved.

  Since the thermosetting resin composition of the present invention can be cured at a low temperature in a short time and can ensure storage stability before curing, it can be suitably used as an adhesive for joining electronic components.

Claims (9)

Contains a phenoxy resin, a cationic curing component, a cationic curing agent, and a stabilizer,
The stabilizer is an ammonium salt;
The thermosetting resin composition, wherein pKa of an anionic conjugate acid in the ammonium salt at 25 ° C. in water is −1 or more. Contains a phenoxy resin, a cationic curing component, a cationic curing agent, and a stabilizer,
The stabilizer is an ammonium salt;
The ammonium salt is a compound represented by any one of the following general formula (1) and the following general formula (2),
The thermosetting resin composition, wherein pKa of an anionic conjugate acid in the ammonium salt at 25 ° C. in water is −1 or more.
In the general formula ^(1), R 1 ~R ^4, the following (A), represents any of (B), and (C). X ⁻ represents an anion.
(A) R ¹ and R ² each independently represent an alkyl group having 1 to 4 carbon atoms, R ³ represents a substituted or unsubstituted aryl group, and R ⁴ represents a substituted or unsubstituted aralkyl. Represents a group.
(B) R < ¹ > -R < ⁴ > represents a C1-C3 alkyl group each independently.
(C) R ^{1 to} R ³ each independently represents an alkyl group having 1 to 4 carbon atoms, and R ⁴ represents a substituted or unsubstituted aryl group.
However, In the general formula (2), ^{R 1} represents an alkyl group having 1 to 4 carbon ^atoms, R 2 to R ⁶ are each independently a hydrogen atom, and alkyl group having 1 to 4 carbon atoms Represents either. Independently, R ² and R ³ , R ³ and R ⁴ , R ⁴ and R ⁵ , and R ⁵ and R ⁶ may be combined to form an aromatic ring. X ⁻ represents an anion. The thermosetting resin composition according to claim 2, wherein X ⁻ in the general formula (1) and the general formula (2) is an anion of a carboxylic acid. X ⁻ in the general formula (1) and the general formula (2) is any one of an anion of benzoic acid, an anion of naphthalenecarboxylic acid, diphenylacetic acid anion, trifluoroacetic acid anion, and 2-ethylhexanoic acid anion. The thermosetting resin composition according to any one of 2 to 3.   The thermosetting resin composition according to any one of claims 1 to 4, wherein the cationic curing component is an epoxy compound. The thermosetting resin composition according to any one of claims 1 to 5, wherein the cationic curing agent is a sulfonium borate complex represented by the following general formula (3).
In the general formula (3), Y ⁺ represents a sulfonium cation, and Z represents a halogen atom. The thermosetting resin composition according to claim 6, wherein Y ⁺ in the general formula (3) is a sulfonium cation represented by the following general formula (4).
In the general formula (4), R ¹¹ represents an aralkyl group, R ¹² represents an optionally branched alkyl group having 1 to 4 carbon atoms, and m is an integer of 1 to 3. A thermosetting sheet comprising the thermosetting resin composition according to claim 1. It is represented by either of the following general formula (1) and the following general formula (2),
X in the general formula (1) and the general formula (2) ⁻ Is represented by any one of the following structural formulas (I) to (VI).
However, in the general formula (1), R ¹ ~ R ⁴ Represents one of the following (A), (B), and (C).
(A) R ¹ And R ² Each independently represents an alkyl group having 1 to 4 carbon atoms; ³ Represents an unsubstituted aryl group, R ⁴ Represents a substituted or unsubstituted aralkyl group.
(B) R ¹ ~ R ⁴ Each independently represents an alkyl group having 1 to 3 carbon atoms.
(C) R ¹ ~ R ³ Each independently represents an alkyl group having 1 to 4 carbon atoms; ⁴ Represents an unsubstituted aryl group.
However, in the general formula (2), R ¹ Represents an alkyl group having 1 to 4 carbon atoms, R ² ~ R ⁶ Each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Each independently R ² And R ³ , R ³ And R ⁴ , R ⁴ And R ⁵ And R ⁵ And R ⁶ Together may form an aromatic ring.