Curable resin composition for electronic devices

Abstract

The purpose of the present invention is to provide a curable resin composition for electronic devices, the composition having excellent inkjet coatability and yielding a cured product that is excellent in terms of low outgas properties and heat resistance. The present invention is a curable resin composition for electronic devices, which is used by being applied by means of an inkjet method, and which contains a cationic polymerizable compound and a cationic photopolymerization initiator. The cationic polymerizable compound includes: a cationic polymerizable compound (A) having at least one structure selected from the group consisting of a structure in which two aliphatic 6-membered rings share at least one side, a structure in which two aliphatic 5-membered rings share at least one side and a structure in which one aliphatic 6-membered ring and one aliphatic 5-membered ring share at least one side; an oxetanyl group-containing cationic polymerizable compound (B) other than the cationic polymerizable compound (A); and a difunctional cationic polymerizable compound (C) other than the cationic polymerizable compound (A) and the cationic polymerizable compound (B). The viscosity of the curable resin composition for electronic devices at 25°C is 5-50 mPa·s.

Description

Curable resin composition for electronic devices

[0001] The present invention relates to a curable resin composition for an electronic device.

[0002] In recent years, there has been a demand for materials that have an appropriate viscosity, excellent coatability, and excellent curability as curable resin compositions for electronic devices used in adhesives for touch panels, solder resists for circuit boards, and the like.

[0003] Touch panels are used in electronic devices such as mobile phones, smartphones, car navigation systems, and personal computers. Capacitive touch panels, in particular, are rapidly gaining popularity due to their excellent functionality. In particular, in recent years, the development of organic EL display elements equipped with capacitive touch panels has progressed. Capacitive touch panels are generally constructed by laminating a cover panel, an adhesive layer, and a substrate. The adhesive layer is required to have excellent transparency and adhesive strength to an adherend. For example, Patent Document 1 discloses an adhesive layer containing a (meth)acrylic polymer obtained by polymerizing specific monomer components as such an adhesive layer.

[0004] On the other hand, a circuit board generally has a circuit with a wiring pattern formed on a base material made of an insulating material, and the outermost surface is covered with a protective film called solder resist for the purposes of protecting the circuit and insulating it from the outside. Furthermore, the use of solder resist can prevent solder bridging, which occurs when solder adheres to wiring and shorts out when mounting components or connecting to external wiring. For example, as disclosed in Patent Document 2, a photosensitive curable resin composition is used for the solder resist to form a pattern.

[0005] JP 2014-034655 A JP 08-259663 A

[0006] In recent years, in order to quickly and uniformly apply curable resin compositions in response to the trend toward thinner devices and finer solder resist patterns, application by an inkjet method has been carried out. Furthermore, curable resin compositions for electronic devices, such as sealants for organic EL display elements, are required to have excellent heat resistance and low outgassing properties in manufacturing processes that require high-temperature treatment after curing, such as a process of forming an inorganic material film by a CVD method. However, when conventional curable resin compositions are adjusted to have a viscosity suitable for application by the inkjet method, there has been a problem in that the resulting cured product may have poor heat resistance and low outgassing properties.

[0007] An object of the present invention is to provide a curable resin composition for electronic devices that has excellent inkjet coating properties and produces a cured product with low outgassing properties and excellent heat resistance.

[0008] Disclosure 1 provides a curable resin composition for electronic devices to be applied by an inkjet method, the curable resin composition comprising a cationically polymerizable compound and a photocationic polymerization initiator, the cationically polymerizable compound having at least one structure selected from the group consisting of a structure in which two aliphatic six-membered rings share at least one side, a structure in which two aliphatic five-membered rings share at least one side, and a structure in which one aliphatic six-membered ring and one aliphatic five-membered ring share at least one side, a cationically polymerizable compound (B) having an oxetanyl group other than the cationically polymerizable compound (A), and a bifunctional cationically polymerizable compound (C) other than the cationically polymerizable compound (A) and the cationically polymerizable compound (B), and the curable resin composition for electronic devices has a viscosity at 25°C of 5 mPa·s or more and 50 mPa·s or less. Disclosure 2 relates to the curable resin composition for electronic devices of Disclosure 1, wherein the content of the cationically polymerizable compound (A) is 2 parts by mass or more and 30 parts by mass or less per 100 parts by mass of the cationically polymerizable compound. Disclosure 3 relates to the curable resin composition for electronic devices of Disclosure 1 or 2, wherein the content of the cationically polymerizable compound (B) is 2 parts by mass or more and 60 parts by mass or less per 100 parts by mass of the cationically polymerizable compound. Disclosure 4 relates to the curable resin composition for electronic devices of Disclosure 1, 2, or 3, wherein the cationically polymerizable compound (A) has at least one skeleton selected from the group consisting of the following formulas (1-1), (1-2), (1-3), and (1-4). Disclosure 5 relates to the curable resin composition for electronic devices of Disclosure 1, 2, 3, or 4, wherein the cationically polymerizable compound (A) is an alicyclic epoxy compound. Disclosure 6 is the curable resin composition for an electronic device according to Disclosure 1, 2, 3, 4, or 5, wherein the cationically polymerizable compound (A) has a molecular weight of 50 or more and 500 or less. Disclosure 7 is the curable resin composition for an electronic device according to Disclosure 1, 2, 3, 4, 5, or 6, wherein the cationically polymerizable compound (B) has a molecular weight of 50 or more and 1000 or less. Disclosure 8 is the curable resin composition for an electronic device according to Disclosure 1, 2, 3, 4, 5, 6, or 7, wherein the cationically polymerizable compound (C) has a molecular weight of 50 or more and 1000 or less.

[0009]

[0010] The present invention is described in detail below. The present inventors investigated using a combination of three specific cationically polymerizable compounds (A) to (C) as a curable resin and adjusting the viscosity at 25°C to a specific range. As a result, they found that it is possible to obtain a curable resin composition for electronic devices that has excellent inkjet coatability and produces a cured product with low outgassing properties and excellent heat resistance, and they have completed the present invention.

[0011] The curable resin composition for electronic devices of the present invention contains a cationically polymerizable compound. The cationically polymerizable compound includes a cationically polymerizable compound (A) having at least one structure selected from the group consisting of a structure in which two aliphatic six-membered rings share at least one side, a structure in which two aliphatic five-membered rings share at least one side, and a structure in which one aliphatic six-membered ring and one aliphatic five-membered ring share at least one side. By containing the cationically polymerizable compound (A) in combination with the cationically polymerizable compound (B) described below, the cured product of the curable resin composition for electronic devices of the present invention exhibits low outgassing properties and excellent heat resistance. In particular, the cationically polymerizable compound (A) preferably has at least one structure selected from the group consisting of a structure in which two aliphatic five-membered rings share at least one side, and a structure in which one aliphatic six-membered ring and one aliphatic five-membered ring share at least one side. In this specification, the term "one side" refers to a bond formed by two adjacent carbon atoms among the carbon atoms constituting the alicyclic ring. For example, a structure sharing one side means that the two adjacent carbon atoms are carbon atoms that constitute both of the two aliphatic rings.

[0012] The cationic polymerizable compound (A) preferably has a total of two or more structures including a structure in which two aliphatic 6-membered rings share at least one side, a structure in which two aliphatic 5-membered rings share at least one side, and a structure in which one aliphatic 6-membered ring and one aliphatic 5-membered ring share at least one side, and more preferably has a total of two or more structures selected from the group consisting of a structure in which two aliphatic 5-membered rings share at least one side, and a structure in which one aliphatic 6-membered ring and one aliphatic 5-membered ring share at least one side. For example, the compound represented by formula (4) described below has a total of three such structures: one structure in which one aliphatic 6-membered ring and one aliphatic 5-membered ring share one side, one structure in which two aliphatic 5-membered rings share two sides, and one structure in which two aliphatic 5-membered rings share one side.

[0013] The cationically polymerizable compound (A) preferably has at least one skeleton selected from the group consisting of the structures in which two aliphatic six-membered rings share at least one side, the structures in which two aliphatic five-membered rings share at least one side, and the structures in which one aliphatic six-membered ring and one aliphatic five-membered ring share at least one side, and at least one skeleton selected from the group consisting of formulas (1-1), (1-2), (1-3), and (1-4). When the cationically polymerizable compound (A) has at least one skeleton selected from the group consisting of formulas (1-1), (1-2), (1-3), and (1-4), the curable resin composition for electronic devices of the present invention exhibits excellent low outgassing properties and heat resistance in its cured product. It is particularly preferred that the cationically polymerizable compound (A) have at least one skeleton selected from the group consisting of formulas (1-1), (1-2), and (1-4). In each of the skeletons of the above formulas (1-1), (1-2), (1-3), and (1-4), at least one of the carbon atoms constituting the skeleton is bonded to an atom (other than a hydrogen atom) outside the skeleton.

[0014] The cationically polymerizable compound (A) may have only one cationically polymerizable group per molecule, or may have two or more cationically polymerizable groups. Examples of the cationically polymerizable group in the cationically polymerizable compound (A) include an epoxy group, a glycidyl group, a glycidyl ether group, an oxetanyl group, a vinyl group, and a vinyl ether group. Among these, a glycidyl group, an epoxy group, and an oxetanyl group are preferred, and an epoxy group is more preferred. Among these, the cationically polymerizable compound (A) is preferably a bifunctional epoxy compound having two epoxy groups per molecule.

[0015] The cationic polymerizable compound (A) is preferably an alicyclic epoxy compound. In this specification, the term "alicyclic epoxy compound" refers to a compound having a structure in which two adjacent carbon atoms constituting an aliphatic ring are directly bonded to oxygen atoms to form an epoxy group. Among these, the cationic polymerizable compound (A) is more preferably an alicyclic epoxy compound having a structure in which two adjacent carbon atoms constituting the aliphatic six-membered ring or the aliphatic five-membered ring are directly bonded to oxygen atoms to form an epoxy group in at least one structure selected from the group consisting of the structure in which two aliphatic six-membered rings share at least one side, the structure in which two aliphatic five-membered rings share at least one side, and the structure in which one aliphatic six-membered ring and one aliphatic five-membered ring share at least one side.

[0016] The preferred lower limit of the molecular weight of the cationically polymerizable compound (A) is 50, and the preferred upper limit is 500. When the molecular weight of the cationically polymerizable compound (A) is within this range, the viscosity of the resulting curable resin composition for electronic devices can be easily adjusted within the range described below, resulting in excellent inkjet coatability and a cured product with low outgassing and excellent heat resistance. A more preferred lower limit of the molecular weight of the cationically polymerizable compound (A) is 100, and a more preferred upper limit is 350. Note that, in this specification, the "molecular weight" refers to the molecular weight calculated from the structural formula for compounds with specific molecular structures. However, for compounds with a wide distribution of polymerization degrees and compounds with unspecified modification sites, the number average molecular weight may be used. Furthermore, in this specification, the number average molecular weight is a value calculated in terms of polystyrene by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent. Examples of columns used in measuring the number average molecular weight in terms of polystyrene by GPC include Shodex LF-804 (manufactured by Showa Denko KK).

[0017] Specific examples of the cationically polymerizable compound (A) include compounds represented by the following formula (2), compounds represented by the following formula (3), compounds represented by the following formula (4), and compounds represented by the following formula (5). Among these, the compounds represented by the following formula (2) and the compounds represented by the following formula (3) are preferred, and the compound represented by the following formula (2) is more preferred.

[0018]

[0019]

[0020]

[0021]

[0022] The preferred lower limit of the content of the cationically polymerizable compound (A) per 100 parts by mass of the cationically polymerizable compound is 2 parts by mass, and the preferred upper limit is 30 parts by mass. When the content of the cationically polymerizable compound (A) is within this range, the viscosity of the resulting curable resin composition for electronic devices can be easily adjusted within the range described below, and the cured product exhibits low outgassing and excellent heat resistance. The preferred lower limit of the content of the cationically polymerizable compound (A) per 100 parts by mass of the cationically polymerizable compound is 5 parts by mass, and the preferred upper limit is 20 parts by mass, and the even more preferred upper limit is 10 parts by mass. Furthermore, the preferred lower limit of the content of the cationically polymerizable compound (A) per 100 parts by mass of the total of the cationically polymerizable compound (A), the cationically polymerizable compound (B) described below, and the cationically polymerizable compound (C) described below is 2 parts by mass, and the preferred upper limit is 30 parts by mass. When the content of the cationically polymerizable compound (A) is within this range, the viscosity of the obtained curable resin composition for electronic devices can be easily adjusted within the range described below, and the cured product will have excellent low outgassing properties and heat resistance. A more preferred lower limit of the content of the cationically polymerizable compound (A) per 100 parts by mass of the total of the cationically polymerizable compound (A), the cationically polymerizable compound (B) described below, and the cationically polymerizable compound (C) described below is 5 parts by mass, a more preferred upper limit is 20 parts by mass, and a still more preferred upper limit is 10 parts by mass.

[0023] The cationically polymerizable compound includes a cationically polymerizable compound (B) having an oxetanyl group other than the cationically polymerizable compound (A). The cationically polymerizable compound (B) is a compound that does not have a structure in which two aliphatic six-membered rings share at least one side, a structure in which two aliphatic five-membered rings share at least one side, or a structure in which one aliphatic six-membered ring and one aliphatic five-membered ring share at least one side, but has an oxetanyl group. By containing the cationically polymerizable compound (B) in combination with the cationically polymerizable compound (A), the curable resin composition for electronic devices of the present invention exhibits low outgassing properties and excellent heat resistance in the cured product. In particular, by containing the cationically polymerizable compound (B), the curable resin composition for electronic devices of the present invention exhibits a high glass transition temperature in the cured product. Furthermore, by containing the cationically polymerizable compound (B) in combination with the cationically polymerizable compound (C) described below, the viscosity of the curable resin composition for electronic devices of the present invention can be easily adjusted to the range described below.

[0024] The cationically polymerizable compound (B) may have only one oxetanyl group in one molecule, or may have two or more oxetanyl groups.

[0025] The preferred lower limit of the molecular weight of the cationically polymerizable compound (B) is 50, and the preferred upper limit is 1,000. When the molecular weight of the cationically polymerizable compound (B) is within this range, the viscosity of the resulting curable resin composition for electronic devices can be easily adjusted within the range described below, and the cured product has a higher glass transition temperature and is more excellent in low outgassing properties and heat resistance. The more preferred lower limit of the molecular weight of the cationically polymerizable compound (B) is 100, and the more preferred upper limit is 700.

[0026] Specific examples of the cationically polymerizable compound (B) include 3-ethyl-3-((2-ethylhexyloxy)methyl)oxetane, 3-ethyl-3-((3-ethyloxetan-3-yl)methoxymethyl)oxetane, (3-ethyloxetan-3-yl)methyl(meth)acrylate, and 4,4'-bis((3-ethyl-3-oxetanyl)methoxymethyl)biphenyl. In this specification, the term "(meth)acrylate" means acrylate or methacrylate.

[0027] The preferred lower limit of the content of the cationically polymerizable compound (B) per 100 parts by mass of the cationically polymerizable compound is 2 parts by mass, and the preferred upper limit is 60 parts by mass. When the content of the cationically polymerizable compound (B) is within this range, the viscosity of the resulting curable resin composition for electronic devices can be easily adjusted within the range described below, and the cured product has a higher glass transition temperature, low outgassing properties, and excellent heat resistance. The preferred lower limit of the content of the cationically polymerizable compound (B) per 100 parts by mass of the cationically polymerizable compound is 5 parts by mass, and the preferred upper limit is 50 parts by mass. Furthermore, the preferred lower limit of the content of the cationically polymerizable compound (B) per 100 parts by mass of the total of the cationically polymerizable compound (A), the cationically polymerizable compound (B), and the cationically polymerizable compound (C) described below is 2 parts by mass, and the preferred upper limit is 60 parts by mass. When the content of the cationically polymerizable compound (B) is within this range, the viscosity of the obtained curable resin composition for electronic devices can be easily adjusted within the range described below, and the cured product has a higher glass transition temperature and is more excellent in low outgassing properties and heat resistance. A more preferred lower limit of the content of the cationically polymerizable compound (B) per 100 parts by mass of the total of the cationically polymerizable compound (A), the cationically polymerizable compound (B), and the cationically polymerizable compound (C) described below is 5 parts by mass, and a more preferred upper limit is 50 parts by mass.

[0028] The cationically polymerizable compound includes a bifunctional cationically polymerizable compound (C) other than the cationically polymerizable compound (A) and the cationically polymerizable compound (B). By including the cationically polymerizable compound (C) in combination with the cationically polymerizable compound (B), the viscosity of the curable resin composition for an electronic device of the present invention can be easily adjusted to the range described below.

[0029] The cationically polymerizable compound (C) has two cationically polymerizable groups in one molecule. Examples of the cationically polymerizable group in the cationically polymerizable compound (C) include an epoxy group and a vinyl ether group. Among these, an epoxy group is preferred. The two cationically polymerizable groups in the cationically polymerizable compound (C) may be the same or different.

[0030] The preferred lower limit of the molecular weight of the cationically polymerizable compound (C) is 50, and the preferred upper limit is 1,000. When the molecular weight of the cationically polymerizable compound (C) is within this range, the viscosity of the obtained curable resin composition for electronic devices can be easily adjusted to the range described below. The more preferred lower limit of the molecular weight of the cationically polymerizable compound (C) is 100, and the more preferred upper limit is 900.

[0031] Examples of the cationically polymerizable compound (C) include linear or branched bifunctional epoxy compounds and bifunctional alicyclic epoxy compounds not included in the cationically polymerizable compound (A). Examples of the linear or branched bifunctional epoxy compounds include neopentyl glycol diglycidyl ether and 1,7-octadiene diepoxide. Examples of the bifunctional alicyclic epoxy compounds not included in the cationically polymerizable compound (A) include (3,3',4,4'-diepoxy)bicyclohexyl, 3,4-epoxycyclohexylmethyl(3,4-epoxy)cyclohexanecarboxylate, and compounds represented by the following formula (6):

[0032]

[0033] The preferred lower limit of the content of the cationically polymerizable compound (C) per 100 parts by mass of the cationically polymerizable compound is 5 parts by mass, and the preferred upper limit is 90 parts by mass. When the content of the cationically polymerizable compound (C) is within this range, the viscosity of the resulting curable resin composition for electronic devices can be easily adjusted to the range described below. A more preferred lower limit of the content of the cationically polymerizable compound (C) per 100 parts by mass of the cationically polymerizable compound is 10 parts by mass, and the more preferred upper limit is 80 parts by mass. Furthermore, the preferred lower limit of the content of the cationically polymerizable compound (C) per 100 parts by mass of the total of the cationically polymerizable compound (A), the cationically polymerizable compound (B), and the cationically polymerizable compound (C) is 5 parts by mass, and the preferred upper limit is 90 parts by mass. When the content of the cationically polymerizable compound (C) is within this range, the viscosity of the resulting curable resin composition for electronic devices can be easily adjusted to the range described below. A more preferred lower limit of the content of the cationically polymerizable compound (C) per 100 parts by mass of the total of the cationically polymerizable compound (A), the cationically polymerizable compound (B), and the cationically polymerizable compound (C) is 10 parts by mass, and a more preferred upper limit thereof is 80 parts by mass.

[0034] The curable resin composition for electronic devices of the present invention contains a cationic photopolymerization initiator. The cationic photopolymerization initiator is not particularly limited as long as it generates a protonic acid or a Lewis acid upon irradiation with light, and may be an ionic photoacid-generating type or a nonionic photoacid-generating type.

[0035] The anion moiety of the ionic photoacid generating cationic photopolymerization initiator may be, for example, BF ４ － , P.F. ６ － , SbF ６ － , (BX ４ ) － (wherein X represents a phenyl group substituted with at least two fluorine atoms or trifluoromethyl groups). Examples of the anion moiety include PF ｍ (C ｎ F２ｎ＋１ ) ６－ｍ － (wherein m is an integer of 0 or more and 5 or less, and n is an integer of 1 or more and 6 or less). Examples of the ionic photoacid-generating photocationic polymerization initiator include aromatic sulfonium salts, aromatic iodonium salts, aromatic diazonium salts, aromatic ammonium salts, and (2,4-cyclopentadien-1-yl)((1-methylethyl)benzene)-Fe salts, which have the anion moiety.

[0036] Examples of the aromatic sulfonium salts include bis(4-(diphenylsulfonio)phenyl)sulfide bishexafluorophosphate, bis(4-(diphenylsulfonio)phenyl)sulfide bishexafluoroantimonate, bis(4-(diphenylsulfonio)phenyl)sulfide bistetrafluoroborate, bis(4-(diphenylsulfonio)phenyl)sulfide tetrakis(pentafluorophenyl)borate, diphenyl-4-(phenylthio)phenylsulfonium hexafluorophosphate, diphenyl-4-(phenylthio)phenylsulfonium hexafluoroantimonate, diphenyl-4-(phenylthio)phenylsulfonium tetrafluoroborate, diphenyl-4-(phenylthio)phenylsulfonium tetrakis(pentafluorophenyl)borate, triphenylsulfonium hexafluorophosphate, Examples of the sulfonium tetrakis(pentafluorophenyl)borate include triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrafluoroborate, triphenylsulfonium tetrakis(pentafluorophenyl)borate, bis(4-(di(4-(2-hydroxyethoxy))phenylsulfonio)phenyl)sulfide bishexafluorophosphate, bis(4-(di(4-(2-hydroxyethoxy))phenylsulfonio)phenyl)sulfide bishexafluoroantimonate, bis(4-(di(4-(2-hydroxyethoxy))phenylsulfonio)phenyl)sulfide bistetrafluoroborate, bis(4-(di(4-(2-hydroxyethoxy))phenylsulfonio)phenyl)sulfide tetrakis(pentafluorophenyl)borate, and tris(4-(4-acetylphenyl)thiophenyl)sulfonium tetrakis(pentafluorophenyl)borate.

[0037] Examples of the aromatic iodonium salts include diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, diphenyliodonium tetrafluoroborate, diphenyliodonium tetrakis(pentafluorophenyl)borate, bis(dodecylphenyl)iodonium hexafluorophosphate, bis(dodecylphenyl)iodonium hexafluoroantimonate, bis(dodecylphenyl)iodonium tetrafluoroborate, bis(dodecylphenyl)iodonium tetrakis(pentafluorophenyl)borate, 4-methylphenyl-4-(1-methylethyl)phenyliodonium hexafluorophosphate, 4-methylphenyl-4-(1-methylethyl)phenyliodonium hexafluoroantimonate, 4-methylphenyl-4-(1-methylethyl)phenyliodonium tetrafluoroborate, and 4-methylphenyl-4-(1-methylethyl)phenyliodonium tetrakis(pentafluorophenyl)borate.

[0038] Examples of the aromatic diazonium salt include phenyldiazonium hexafluorophosphate, phenyldiazonium hexafluoroantimonate, phenyldiazonium tetrafluoroborate, and phenyldiazonium tetrakis(pentafluorophenyl)borate.

[0039] Examples of the aromatic ammonium salt include 1-benzyl-2-cyanopyridinium hexafluorophosphate, 1-benzyl-2-cyanopyridinium hexafluoroantimonate, 1-benzyl-2-cyanopyridinium tetrafluoroborate, 1-benzyl-2-cyanopyridinium tetrakis(pentafluorophenyl)borate, 1-(naphthylmethyl)-2-cyanopyridinium hexafluorophosphate, 1-(naphthylmethyl)-2-cyanopyridinium hexafluoroantimonate, 1-(naphthylmethyl)-2-cyanopyridinium tetrafluoroborate, and 1-(naphthylmethyl)-2-cyanopyridinium tetrakis(pentafluorophenyl)borate.

[0040] Examples of the (2,4-cyclopentadien-1-yl)((1-methylethyl)benzene)-Fe salt include (2,4-cyclopentadien-1-yl)((1-methylethyl)benzene)-Fe(II) hexafluorophosphate, (2,4-cyclopentadien-1-yl)((1-methylethyl)benzene)-Fe(II) hexafluoroantimonate, (2,4-cyclopentadien-1-yl)((1-methylethyl)benzene)-Fe(II) tetrafluoroborate, and (2,4-cyclopentadien-1-yl)((1-methylethyl)benzene)-Fe(II) tetrakis(pentafluorophenyl)borate.

[0041] Examples of the nonionic photoacid generating cationic photopolymerization initiator include nitrobenzyl esters, sulfonic acid derivatives, phosphate esters, phenolsulfonic acid esters, diazonaphthoquinone, and N-hydroxyimide sulfonates.

[0042] Among the above-mentioned cationic photopolymerization initiators, commercially available ones include, for example, cationic photopolymerization initiators manufactured by Midori Chemical Industry Co., Ltd., cationic photopolymerization initiators manufactured by Union Carbide Corporation, cationic photopolymerization initiators manufactured by ADEKA Corporation, cationic photopolymerization initiators manufactured by 3M Corporation, cationic photopolymerization initiators manufactured by BASF Corporation, cationic photopolymerization initiators manufactured by Solvay SA, and cationic photopolymerization initiators manufactured by San-Apro Corporation. Examples of the cationic photopolymerization initiators manufactured by Midori Chemical Industry Co., Ltd. include DTS-200. Examples of the cationic photopolymerization initiators manufactured by Union Carbide Corporation include UVI6990 and UVI6974. Examples of the cationic photopolymerization initiators manufactured by ADEKA Corporation include SP-150 and SP-170. Examples of the cationic photopolymerization initiators manufactured by 3M Corporation include FC-508 and FC-512. Examples of the cationic photopolymerization initiator manufactured by BASF include IRGACURE 261 and IRGACURE 290. Examples of the cationic photopolymerization initiator manufactured by Solvay include PI 2074. Examples of the cationic photopolymerization initiator manufactured by San-Apro include CPI-100P, CPI-200K, CPI-210S, and CPI-410S.

[0043] The content of the cationic photopolymerization initiator is preferably 0.01 parts by mass or more and 10 parts by mass or more per 100 parts by mass of the cationic polymerizable compound. When the content of the cationic photopolymerization initiator is 0.01 parts by mass or more per 100 parts by mass of the cationic polymerizable compound, the resulting curable resin composition for electronic devices has superior curability. When the content of the cationic photopolymerization initiator is 10 parts by mass or less per 100 parts by mass of the cationic polymerizable compound, the curing reaction of the resulting curable resin composition for electronic devices does not become too rapid, resulting in superior workability and a more uniform cured product. A more preferred lower limit of the content of the cationic photopolymerization initiator per 100 parts by mass of the cationic polymerizable compound is 0.05 parts by mass or more and 5 parts by mass or more. The content of the cationic photopolymerization initiator is preferably 0.01 parts by mass or more and 10 parts by mass or more per 100 parts by mass of the total of the cationic polymerizable compound (A), the cationic polymerizable compound (B), and the cationic polymerizable compound (C). When the content of the cationic photopolymerization initiator is 0.01 parts by mass or more per 100 parts by mass of the total of the cationic polymerizable compound (A), the cationic polymerizable compound (B), and the cationic polymerizable compound (C), the resulting curable resin composition for electronic devices has superior curability. When the content of the cationic photopolymerization initiator is 10 parts by mass or less per 100 parts by mass of the total of the cationic polymerizable compound (A), the cationic polymerizable compound (B), and the cationic polymerizable compound (C), the curing reaction of the resulting curable resin composition for electronic devices is not too rapid, resulting in superior workability and a more uniform cured product. The lower limit of the content of the cationic photopolymerization initiator relative to 100 parts by mass of the total of the cationic polymerizable compound (A), the cationic polymerizable compound (B), and the cationic polymerizable compound (C) is more preferably 0.05 parts by mass, and the upper limit thereof is more preferably 5 parts by mass.

[0044] The curable resin composition for electronic devices of the present invention may contain a sensitizer. The sensitizer has the role of further improving the polymerization initiation efficiency of the cationic photopolymerization initiator and further accelerating the curing reaction of the curable resin composition for electronic devices of the present invention.

[0045] Examples of the sensitizer include 9,10-dibutoxyanthracene, 2,4-diethylthioxanthone, 2,2-dimethoxy-1,2-diphenylethan-1-one, benzophenone, 2,4-dichlorobenzophenone, methyl o-benzoylbenzoate, 4,4'-bis(dimethylamino)benzophenone, and 4-benzoyl-4'-methyldiphenyl sulfide.

[0046] The content of the sensitizer is preferably 0.01 parts by mass or more and 3 parts by mass or more per 100 parts by mass of the cationically polymerizable compound. When the content of the sensitizer is 0.01 parts by mass or more per 100 parts by mass of the cationically polymerizable compound, the sensitizing effect is enhanced. When the content of the sensitizer is 3 parts by mass or less per 100 parts by mass of the cationically polymerizable compound, light can be transmitted to deep areas without excessive absorption. The content of the sensitizer is more preferably 0.1 parts by mass or less and 1 part by mass or more per 100 parts by mass of the cationically polymerizable compound. Furthermore, the content of the sensitizer is preferably 0.01 parts by mass or less and 3 parts by mass or more per 100 parts by mass of the total of the cationically polymerizable compound (A), the cationically polymerizable compound (B), and the cationically polymerizable compound (C). When the content of the sensitizer is 0.01 parts by mass or more per 100 parts by mass of the total of the cationically polymerizable compound (A), the cationically polymerizable compound (B), and the cationically polymerizable compound (C), the sensitizing effect is enhanced. When the content of the sensitizer is 3 parts by mass or less per 100 parts by mass of the total of the cationically polymerizable compound (A), the cationically polymerizable compound (B), and the cationically polymerizable compound (C), light can be transmitted to deep areas without excessive absorption. The lower limit of the content of the sensitizer per 100 parts by mass of the total of the cationically polymerizable compound (A), the cationically polymerizable compound (B), and the cationically polymerizable compound (C) is more preferably 0.1 parts by mass, and the upper limit is more preferably 1 part by mass.

[0047] The curable resin composition for electronic devices of the present invention may further contain a silane coupling agent. The silane coupling agent has the role of improving the adhesion between the curable resin composition for electronic devices of the present invention and a substrate or the like.

[0048] Examples of the silane coupling agent include 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltrimethoxysilane, etc. These silane compounds may be used alone or in combination of two or more.

[0049] The content of the silane coupling agent is preferably 0.1 parts by mass or less and 10 parts by mass or less per 100 parts by mass of the cationically polymerizable compound. By using this range of silane coupling agent per 100 parts by mass of the cationically polymerizable compound, the adhesiveness of the resulting curable resin composition for electronic devices can be improved while suppressing bleed-out due to excess silane coupling agent. The content of the silane coupling agent per 100 parts by mass of the cationically polymerizable compound is more preferably 0.5 parts by mass or less and 5 parts by mass or less per 100 parts by mass of the cationically polymerizable compound. The content of the silane coupling agent is preferably 0.1 parts by mass or less and 10 parts by mass or less per 100 parts by mass of the total of the cationically polymerizable compound (A), the cationically polymerizable compound (B), and the cationically polymerizable compound (C). The content of the silane coupling agent is within this range relative to 100 parts by mass of the total of the cationically polymerizable compound (A), the cationically polymerizable compound (B), and the cationically polymerizable compound (C), thereby suppressing bleed-out due to excess silane coupling agent and achieving an excellent effect of improving the adhesiveness of the resulting curable resin composition for electronic devices. The content of the silane coupling agent is more preferably 0.5 parts by mass and 5 parts by mass relative to 100 parts by mass of the total of the cationically polymerizable compound (A), the cationically polymerizable compound (B), and the cationically polymerizable compound (C).

[0050] The curable resin composition for electronic devices of the present invention may contain a curing retarder. By containing the curing retarder, the pot life of the obtained curable resin composition for electronic devices can be extended.

[0051] Examples of the curing retarder include polyether compounds. Examples of the polyether compounds include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and crown ether compounds. Among these, crown ether compounds are preferred.

[0052] The content of the curing retarder is preferably 0.05 parts by mass or less and 5.0 parts by mass or less per 100 parts by mass of the cationically polymerizable compound. By using this range of the curing retarder content per 100 parts by mass of the cationically polymerizable compound, the retardation effect can be enhanced while suppressing the generation of outgassing when curing the resulting curable resin composition for electronic devices. A more preferred lower limit of the curing retarder content per 100 parts by mass of the cationically polymerizable compound is 0.1 parts by mass or less and a more preferred upper limit is 3.0 parts by mass or less. Furthermore, a preferred lower limit of the curing retarder content per 100 parts by mass of the cationically polymerizable compound (A), the cationically polymerizable compound (B), and the cationically polymerizable compound (C) is 0.05 parts by mass or less and a preferred upper limit is 5.0 parts by mass or less per 100 parts by mass of the total of the cationically polymerizable compound (A), the cationically polymerizable compound (B), and the cationically polymerizable compound (C). When the content of the curing retarder is within this range relative to 100 parts by mass of the total of the cationically polymerizable compound (A), the cationically polymerizable compound (B), and the cationically polymerizable compound (C), the retardation effect can be more effectively exhibited while suppressing the generation of outgassing when curing the obtained curable resin composition for electronic devices. A more preferred lower limit of the content of the curing retarder relative to 100 parts by mass of the total of the cationically polymerizable compound (A), the cationically polymerizable compound (B), and the cationically polymerizable compound (C) is 0.1 parts by mass, and a more preferred upper limit is 3.0 parts by mass.

[0053] The curable resin composition for electronic devices of the present invention may further contain a surface modifier within a range that does not impair the object of the present invention. By containing the surface modifier, the flatness of the coating film of the curable resin composition for electronic devices of the present invention can be improved. Examples of the surface modifier include a surfactant and a leveling agent.

[0054] Examples of the surface modifier include silicone-based, acrylic-based, fluorine-based, and olfin-based ones. Commercially available surface modifiers include those manufactured by BYK Japan and AGC Seimi Chemical. Examples of the surface modifiers manufactured by BYK Japan include BYK-340 and BYK-345. Examples of the surface modifiers manufactured by AGC Seimi Chemical include Surflon S-611.

[0055] The curable resin composition for electronic devices of the present invention may contain a compound that reacts with the acid generated in the composition or an ion exchange resin, as long as the object of the present invention is not impaired.

[0056] The compound that reacts with the acid generated in the composition includes a substance that neutralizes the acid, such as a carbonate or bicarbonate of an alkali metal or alkaline earth metal, etc. Specific examples of the compound that can be used include calcium carbonate, calcium bicarbonate, sodium carbonate, and sodium bicarbonate.

[0057] The ion exchange resin may be of the cation exchange type, anion exchange type, or amphoteric ion exchange type, but the cation exchange type or amphoteric ion exchange type capable of adsorbing chloride ions is particularly preferred.

[0058] Furthermore, the curable resin composition for an electronic device of the present invention may contain, as necessary, various known additives such as a thermal cationic polymerization initiator, a heat curing agent, a reinforcing agent, a softener, a plasticizer, a viscosity modifier, an ultraviolet absorber, and an antioxidant.

[0059] The curable resin composition for electronic devices of the present invention preferably does not contain a solvent from the viewpoint of further suppressing outgassing. The curable resin composition for electronic devices of the present invention can have excellent inkjet coating properties even without containing a solvent. In this specification, "containing no solvent" means that the solvent content is less than 1000 ppm.

[0060] Examples of a method for producing the curable resin composition for an electronic device of the present invention include a method of mixing a cationically polymerizable compound, a photocationic polymerization initiator, and an additive such as a sensitizer, which is added as needed, using a mixer such as a homodisper, a homomixer, a universal mixer, a planetary mixer, a kneader, or a three-roll mill.

[0061] The curable resin composition for an electronic device of the present invention is used for application by an inkjet method. The inkjet method may be a non-heated inkjet method or a heated inkjet method. In this specification, the "non-heated inkjet method" refers to an inkjet application method at a coating head temperature of less than 28°C, and the "heated inkjet method" refers to an inkjet application method at a coating head temperature of 28°C or higher.

[0062] The thermal inkjet method uses an inkjet coating head equipped with a heating mechanism. By incorporating a heating mechanism into the inkjet coating head, the viscosity and surface tension of the curable resin composition for electronic devices can be reduced when the composition is ejected.

[0063] Examples of inkjet coating heads equipped with the above-mentioned heating mechanism include the KM1024 series manufactured by Konica Minolta, Inc. and the SG1024 series manufactured by Fujifilm Dimatix Corporation.

[0064] When the curable resin composition for electronic devices of the present invention is used for coating by the thermal inkjet method, the heating temperature of the coating head is preferably in the range of 28° C. or more and 80° C. or less. When the heating temperature of the coating head is in this range, an increase in viscosity over time of the curable resin composition for electronic devices is further suppressed, and the discharge stability is further improved.

[0065] The curable resin composition for electronic devices of the present invention has a viscosity at 25°C of 5 mPa·s at a lower limit and 50 mPa·s at an upper limit. The viscosity at 25°C within this range allows for suitable application by an inkjet method. The curable resin composition for electronic devices of the present invention has a viscosity at 25°C of preferably 8 mPa·s at a lower limit and more preferably 10 mPa·s at a lower limit. Furthermore, the curable resin composition for electronic devices of the present invention has a viscosity at 25°C of preferably 40 mPa·s at a higher limit and more preferably 30 mPa·s at a lower limit. In this specification, the term "viscosity" refers to a value measured using an E-type viscometer at 100 rpm. Examples of the E-type viscometer include a VISCOMETER TV-22 (manufactured by Toki Sangyo Co., Ltd.), and a CP1 type cone plate can be used.

[0066] The curable resin composition for electronic devices of the present invention has a surface tension at 25°C of preferably 15 mN / m at its lower limit and 35 mN / m at its upper limit. Having a surface tension at 25°C within this range allows for more suitable application by an inkjet method. A more preferred lower limit of the surface tension at 25°C is 20 mN / m, and an even more preferred lower limit is 22 mN / m. Furthermore, a more preferred upper limit of the surface tension at 25°C is 30 mN / m, and an even more preferred upper limit is 28 mN / m. The surface tension refers to a value measured by the Wilhelmy method using a dynamic wettability tester. An example of the dynamic wettability tester is the WET-6100 model (manufactured by Rhesca Corporation).

[0067] The curable resin composition for electronic devices of the present invention is curable at a wavelength of 300 nm or more and 400 nm or less and at a temperature of 300 mJ / cm ２ More than 3000mJ / cm ２ The curing can be achieved by irradiating the resin with the following integrated amount of light.

[0068] Examples of light sources used for the light irradiation include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, excimer lasers, chemical lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, sodium lamps, halogen lamps, xenon lamps, LED lamps, fluorescent lamps, sunlight, and electron beam irradiation devices. These light sources may be used alone or in combination of two or more. These light sources are appropriately selected according to the absorption wavelength of the cationic photopolymerization initiator.

[0069] Examples of means for irradiating the curable resin composition for electronic devices of the present invention with light include simultaneous irradiation with various light sources, sequential irradiation with a time lag, and a combination of simultaneous irradiation and sequential irradiation, and any of the irradiation means may be used.

[0070] In the curable resin composition for electronic devices of the present invention, the lower limit of the glass transition temperature of the cured product of the curable resin composition for electronic devices is preferably 50°C. When the glass transition temperature of the cured product is 50°C or higher, the curable resin composition for electronic devices of the present invention has superior heat resistance. The lower limit of the glass transition temperature of the cured product is preferably 60°C, and more preferably 70°C. There is no particular preferred upper limit of the glass transition temperature of the cured product, but the practical upper limit is 200°C. In this specification, the "glass transition temperature" refers to the temperature at which a maximum due to micro-Brownian motion appears among the maximums of loss tangent (tan δ) obtained by dynamic viscoelasticity measurement, and can be measured by a conventionally known method using a viscoelasticity measuring device or the like. The cured product for which the glass transition temperature is measured can be obtained by the following method. That is, the curable resin composition for electronic devices was applied to a PET film so that the thickness of the cured product was 0.3 mm, and then the cured product was exposed to ultraviolet light of 365 nm wavelength using an LED UV lamp at an illuminance of 1000 mW / cm in a dry chamber with a dew point of −50° C. or less. ２ 1500 mJ / cm from the top ２ Irradiation, 1500mJ / cm from the bottom surface ２ It can be obtained by irradiation.

[0071] The curable resin composition for electronic devices of the present invention preferably has an outgassing amount, as quantified in toluene terms, of less than 5,000 ppm when a cured product of the curable resin composition for electronic devices is subjected to thermal desorption GC-MS measurement under thermal desorption conditions of 110°C and 30 minutes. Having an outgassing amount of less than 5,000 ppm results in an excellent effect of suppressing the occurrence of dark spots when the resulting curable resin composition for electronic devices is used as a sealant for an organic EL display element. The outgassing amount is more preferably less than 2,000 ppm, even more preferably less than 500 ppm, and most preferably 0 ppm. The outgassing amount can be measured by measuring the amount of gas components generated when 1 mg of a cured product of the curable resin composition for electronic devices is heated under thermal desorption conditions of 110°C and 30 minutes in a dry chamber with a dew point of -50°C or less using a thermal desorption apparatus and a GC-MS apparatus. The cured product to be subjected to the thermal desorption GC-MS measurement can be obtained by the following method. That is, the curable resin composition for electronic devices was applied to a PET film so that the thickness of the cured product was 10 μm, and then, in a dry chamber with a dew point of −50° C. or less, the curable resin composition for electronic devices was irradiated with ultraviolet light having a wavelength of 365 nm using an LED UV lamp at an illuminance of 1000 mW / cm ２ at 2000 mJ / cm ２ It can be obtained by irradiation.

[0072] The curable resin composition for electronic devices of the present invention is used as a sealant for electronic devices, an adhesive for electronic devices, a coating agent for electronic devices, etc. In particular, it is suitably used as a sealant for organic EL display elements.

[0073] According to the present invention, it is possible to provide a curable resin composition for electronic devices which has excellent inkjet coating properties and produces a cured product with low outgassing properties and excellent heat resistance.

[0074] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0075] (Synthesis of Compound Represented by Formula (3)) Tricyclo[6.2.1.0２，７ 148 parts by mass of undec-4-ene (manufactured by Tokyo Chemical Industry Co., Ltd.) and 173 parts by mass of m-chloroperbenzoic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were reacted in a toluene solvent at 25°C for 12 hours. The resulting solution was subjected to a separation treatment with an aqueous sodium sulfite solution, an aqueous sodium hydroxide solution, and pure water, in that order. After separation, the toluene solvent was removed from the main layer by evaporation, yielding a compound represented by the above formula (3).

[0076] (Examples 1 to 15, Comparative Examples 1 to 4) According to the compounding ratios shown in Tables 1 and 2, each material was uniformly stirred and mixed using a Homo Disper-type stirring mixer at a stirring speed of 3000 rpm to prepare curable resin compositions for electronic devices in Examples 1 to 15 and Comparative Examples 1 to 4. The Homo Disper-type stirring mixer used was a Homo Disper L model (manufactured by Primix Corporation). The viscosity of each obtained curable resin composition for electronic devices was measured using an E-type viscometer with a CP1-type cone plate at 25°C and 100 rpm. A VISCOMETER TV-22 (manufactured by Toki Sangyo Co., Ltd.) was used as the E-type viscometer. The results are shown in Tables 1 and 2. The viscosity of the curable resin composition for electronic devices obtained in Comparative Example 4 was not measured because precipitation was observed. Each of the obtained curable resin compositions for electronic devices was applied onto a PET film, and then the film was exposed to ultraviolet light at a wavelength of 365 nm using an LED UV lamp at an illuminance of 1000 mW / cm in a dry chamber with a dew point of −50° C. or less. ２ 1500 mJ / cm from the top ２ Irradiation, 1500mJ / cm from the bottom surface ２ The cured product was irradiated with light. This resulted in a cured product measuring 20 mm in length, 5 mm in width, and 0.3 mm in thickness. An SQ series LED UV lamp (manufactured by Quark Technology) was used. The dynamic viscoelasticity of the resulting cured product was measured using a dynamic viscoelasticity measuring device (manufactured by IT Measurement and Control Co., Ltd., "DVA-200") in the temperature range of 0°C to 200°C, at a heating rate of 10°C / min, and at a frequency of 10 Hz, and the temperature at which the loss tangent (tan δ) reached its maximum value was determined as the glass transition temperature. The results are shown in Tables 1 and 2. Note that the glass transition temperatures of the cured products of the curable resin compositions for electronic devices obtained in Comparative Examples 2 to 4 were not measured.

[0077] <Evaluation> The curable resin compositions for electronic devices obtained in the examples and comparative examples were evaluated as follows. The results are shown in Tables 1 and 2.

[0078] (Inkjet Coatability) A coating test was conducted in which each of the obtained curable resin compositions for electronic devices was printed in a grid pattern at a pitch of 25 μm using an inkjet printer with a droplet volume of 10 picoliters onto alkali-cleaned alkali-free glass. The inkjet printer used was a Material Printer DMP-2831 (manufactured by Fujifilm Dimatix Corporation), and the alkali-free glass used was an AN100 (manufactured by AGC). The inkjet coatability was evaluated as follows: "◎" indicates that the printed area was uniformly printed without uncoated areas or unevenness; "◯" indicates that there were no uncoated areas but slight streak-like unevenness; "△" indicates that there were no uncoated areas but clear streak-like unevenness; and "×" indicates that there were uncoated areas.

[0079] (Low outgassing property) Each of the curable resin compositions for electronic devices obtained in the examples and comparative examples was applied onto a PET film so that the thickness of the cured product was 10 μm. Thereafter, in a dry chamber with a dew point of −50° C. or less, ultraviolet light having a wavelength of 365 nm was applied from an LED UV lamp at an illuminance of 1000 mW / cm. ２ at 2000 mJ / cm ２A cured product was obtained by irradiating the material. The LED UV lamp used was an SQ series (manufactured by Quark Technology). 1 mg of the resulting cured product was heated at 100°C for 30 minutes using a thermal desorption device and a GC-MS device, and the amount of outgassing, calculated as toluene, was measured. The specific measurement conditions are shown below. Thermal desorption apparatus: Turbo Matrix 650 (PerkinElmer) Thermal desorption conditions: 100°C, 30 minutes Split: Inlet 15 mL / min, outlet 15 mL / min, injection volume 5.2% GC-MS apparatus: JMS Q1000 (JEOL) Separation column: EQUITY-1 (non-polar) 0.32 mm x 60 m x 0.25 μm GC heating rate: 40°C 4 minutes → 10°C / min → 300°C 10 minutes Carrier gas (flow rate): He (1.5 mL / min) MS measurement range: 29 to 600 amu (scan 500 ms) Ionization voltage: 70 eV MS temperature: ion source 230°C, interface 250°C The low outgassing property was evaluated as follows: when the amount of outgassing was less than 500 ppm, "◎", when it was 500 ppm or more and less than 2000 ppm, "◯", when it was 2000 ppm or more and less than 5000 ppm, "Δ", and when it was 5000 ppm or more, "×". Note that the curable resin compositions for electronic devices obtained in Comparative Examples 3 and 4 were not evaluated for low outgassing property.

[0080] (Heat Resistance) Each of the curable resin compositions for electronic devices obtained in the Examples and Comparative Examples was subjected to ultraviolet light of 395 nm at 3000 mJ / cm using an LED UV lamp. ２The composition was cured by irradiation. An SQ series LED UV lamp (manufactured by Quark Technology) was used as the LED UV lamp. The obtained cured product was heated in an oven at 100°C, and then the appearance was observed at 200x magnification using a scanning electron microscope (SEM). Ten cured products each having an area of ​​5 mm x 5 mm were observed, and the percentage of cured products in which cracks or wrinkles were confirmed on the surface (the crack and wrinkle occurrence rate) was calculated. An S-4800 (manufactured by Hitachi High-Technologies Corporation) was used as the scanning electron microscope (SEM). Heat resistance was evaluated by assigning a "◎" when the crack and wrinkle occurrence rate was less than 10%, a "○" when it was 10% or more but less than 30%, a "△" when it was 30% or more but less than 50%, and an "×" when it was 50% or more. Note that the heat resistance of the curable resin compositions for electronic devices obtained in Comparative Examples 3 and 4 was not evaluated.

[0081]

[0082]

[0083] According to the present invention, it is possible to provide a curable resin composition for electronic devices which has excellent inkjet coating properties and produces a cured product with low outgassing properties and excellent heat resistance.

Claims

1. A curable resin composition for electronic devices used for coating by an inkjet method, comprising: Contains a cationic polymerizable compound and a photocationic polymerization initiator, the cationic polymerizable compound has in one molecule at least two or more kinds of structures selected from the group consisting of a structure in which two aliphatic 6-membered rings share at least one side, a structure in which two aliphatic 5-membered rings share at least one side, and a structure in which one aliphatic 6-membered ring and one aliphatic 5-membered ring share at least one side, and has two epoxy groups in one molecule; a cationic polymerizable compound (B) having an oxetanyl group other than the cationic polymerizable compound (A); and a bifunctional cationic polymerizable compound (C) other than the cationic polymerizable compound (A) and the cationic polymerizable compound (B); The viscosity of the curable resin composition for electronic devices at 25° C. is 5 mPa·s or more and 50 mPa·s or less. A curable resin composition for electronic devices comprising:

2. 2. The curable resin composition for electronic devices according to claim 1, wherein the content of the cationically polymerizable compound (A) is 2 parts by mass or more and 30 parts by mass or less in 100 parts by mass of the cationically polymerizable compound.

3. 3. The curable resin composition for electronic devices according to claim 1, wherein the content of the cationically polymerizable compound (B) is 2 parts by mass or more and 60 parts by mass or less in 100 parts by mass of the cationically polymerizable compound.

4. The curable resin composition for electronic devices according to claim 1 or 2, wherein the cationically polymerizable compound (A) has at least one skeleton selected from the group consisting of the following formulas (1-1), (1-2), (1-3), and (1-4). 【Chemistry 1】

5. 3. The curable resin composition for electronic devices according to claim 1, wherein the cationically polymerizable compound (A) is an alicyclic epoxy compound.

6. 3. The curable resin composition for electronic devices according to claim 1, wherein the cationically polymerizable compound (A) has a molecular weight of 50 or more and 500 or less.

7. 3. The curable resin composition for electronic devices according to claim 1, wherein the cationically polymerizable compound (B) has a molecular weight of 50 or more and 1,000 or less.

8. 3. The curable resin composition for electronic devices according to claim 1, wherein the cationically polymerizable compound (C) has a molecular weight of 50 or more and 1,000 or less.

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