Curable resin composition for electronic device

Abstract

To provide a curable resin composition for an electronic device, the resin composition materializing a cured substance having a low dielectric constant and excellent deformation resistance and toughness.SOLUTION: A curable resin composition for an electronic device containing curable resin and a polymerization initiator is provided, the curable resin includes epoxidized vegetable oil and an alicyclic epoxy compound having two or more alicyclic epoxy groups in one molecule, and the epoxidized vegetable oil has a viscosity exceeding 85 mPa s when measured at 25°C and 100 rpm using an E-type viscometer.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a curable resin composition for electronic devices. [Background technology]

[0002] 2. Description of the Related Art In recent years, there has been a demand for materials having appropriate viscosity, excellent coatability, and excellent curability as curable resin compositions for electronic devices used in, for example, adhesives for touch panels and solder resists for circuit boards.

[0003] Touch panels are used in electronic devices such as mobile phones, smartphones, car navigation systems, personal computers, etc. Among them, capacitive touch panels are rapidly becoming popular due to their excellent functionality. A capacitive touch panel is 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 a specific monomer component as such an adhesive layer.

[0004] On the other hand, a circuit board generally has a circuit formed by 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 purpose of protecting the circuit and insulating it from the outside of the circuit. In addition, by using the solder resist, it is possible to prevent a solder bridge in which solder adheres between wirings and causes a short circuit 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. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2014-034655 A [Patent Document 2] Japanese Patent Application Publication No. 08-259663 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, as capacitive touch panels have become thinner and larger, in order to prevent a decrease in the response speed of the touch panel, the curable resin composition used in the adhesive layer is required to have dielectric properties such as a low dielectric constant and a low dielectric loss tangent. In addition, the curable resin contained in the curable resin composition used in the solder resist has a polar group such as an acid group to impart photosensitivity, so that the dielectric constant and dielectric loss tangent are high, and as a result, when a high-frequency voltage is applied to the circuit, transmission delay and signal loss occur. Therefore, such curable resin compositions are also required to have dielectric properties such as a low dielectric constant and a low dielectric loss tangent. Furthermore, curable resin compositions used in electronic devices are required to provide a cured product that is free from deformation, cracks, and the like, even after the electronic device is subjected to an external impact, such as when the electronic device is dropped, or after the electronic device is subjected to a force, such as bending.

[0007] An object of the present invention is to provide a curable resin composition for electronic devices, which provides a cured product having a low dielectric constant and excellent deformation resistance and toughness. [Means for solving the problem]

[0008] Disclosure 1 relates to a curable resin composition for electronic devices, which contains a curable resin and a polymerization initiator, wherein the curable resin contains an epoxidized vegetable oil and an alicyclic epoxy compound having two or more alicyclic epoxy groups in one molecule, and the epoxidized vegetable oil has a viscosity of more than 85 mPa s as measured at 25°C and 100 rpm using an E-type viscometer. The present disclosure 2 relates to the curable resin composition for electronic devices according to the present disclosure 1, wherein the epoxidized vegetable oil contains a compound represented by the following formula (1): The present disclosure 3 is the curable resin composition for electronic devices according to the present disclosure 1 or 2, in which the content of the epoxidized vegetable oil is 10 parts by mass or more and 40 parts by mass or less in 100 parts by mass of the total of the epoxidized vegetable oil and the alicyclic epoxy compound having two or more alicyclic epoxy groups in one molecule. The present disclosure 4 relates to a curable resin composition for electronic devices according to the present disclosure 1, 2, or 3, wherein the alicyclic epoxy compound having two or more alicyclic epoxy groups in one molecule includes at least one selected from the group consisting of a compound represented by the following formula (2) and a compound represented by the following formula (3): The present disclosure 5 is the curable resin composition for an electronic device according to the present disclosure 1, 2, 3 or 4, wherein the polymerization initiator includes at least one selected from the group consisting of a photocationic polymerization initiator and a photoradical polymerization initiator. The present disclosure 6 is the curable resin composition for electronic devices according to the present disclosure 1, 2, 3, 4 or 5, further comprising a sensitizer. The present disclosure 7 is a curable resin composition for electronic devices according to 1, 2, 3, 4, 5 or 6, further comprising a surface conditioner. The present disclosure 8 is the curable resin composition for electronic devices according to the present disclosure 1, 2, 3, 4, 5, 6, or 7, having a viscosity of 40 mPa·s or more and 110 mPa·s or less, measured using an E-type viscometer at 25° C. and 100 rpm. The present disclosure 9 is the curable resin composition for electronic devices according to the present disclosure 1, 2, 3, 4, 5, 6, 7, or 8, wherein the dielectric constant of a cured product of the curable resin composition for electronic devices measured under conditions of 25° C. and 1 GHz is 3.5 or less.

[0009] [ka]

[0010] In formula (1), R 1 and R 2 are each independently a linear or branched organic group having 1 to 20 carbon atoms.

[0011] [ka]

[0012] In formula (2), R 3 are each independently an alkyl group having 1 to 10 carbon atoms; R 4 are each independently a bond or an alkylene group having 1 to 6 carbon atoms, and n is an integer of 0 to 1,000.

[0013] [ka]

[0014] In formula (3), R 5 are each independently an alkyl group having 1 to 10 carbon atoms; R 6 is a bond or an alkylene group having 1 to 6 carbon atoms, R 7 are each independently an alkyl group having 1 to 10 carbon atoms, a group represented by the following formula (4-1), a group represented by the following formula (4-2), a group represented by the following formula (4-3), or a group represented by the following formula (4-4). In formula (3), l represents an integer of 0 to 1000, and m represents an integer of 1 to 100. However, R 7 is not a group represented by the following formula (4-1), m represents an integer of 2 or more and 100 or less.

[0015] [ka]

[0016] In formulas (4-1) to (4-4), R 8 represents a bond or an alkylene group having 1 to 6 carbon atoms; in formula (4-3), R 9 represents hydrogen or an alkyl group having 1 to 6 carbon atoms; R 10 represents a bond or a methylene group, and in formula (4-4), R 11 represents hydrogen or a methyl group.

[0017] The present invention will be described in detail below. The present inventors have investigated the use of a combination of an epoxidized vegetable oil having a viscosity exceeding a specific value and an alicyclic epoxy compound having two or more alicyclic epoxy groups in one molecule as a curable resin, and have found that it is possible to obtain a curable resin composition for electronic devices that has a low dielectric constant when cured and is excellent in deformation resistance and toughness, thereby completing the present invention.

[0018] The curable resin composition for electronic devices of the present invention contains a curable resin. The curable resin contains an epoxidized vegetable oil. By containing the epoxidized vegetable oil, the curable resin composition for electronic devices of the present invention can easily lower the dielectric constant of the cured product. In addition, in recent years, the idea of ​​carbon neutrality, in which the total of greenhouse gas emissions minus the amount absorbed and removed is zero, is becoming more widespread around the world. The curable resin composition for electronic devices of the present invention containing the epoxidized vegetable oil can be said to be able to reduce the burden on the environment in accordance with carbon neutrality.

[0019] The epoxidized vegetable oil has a viscosity of more than 85 mPa·s measured at 25°C and 100 rpm using an E-type viscometer. Hereinafter, an epoxidized vegetable oil having a viscosity of more than 85 mPa·s measured at 25°C and 100 rpm using an E-type viscometer is also referred to as "epoxidized vegetable oil according to the present invention." When the viscosity of the epoxidized vegetable oil according to the present invention exceeds 85 mPa·s, the curable resin composition for electronic devices according to the present invention provides a cured product having excellent deformation resistance and toughness. The preferable lower limit of the viscosity of the epoxidized vegetable oil according to the present invention is 86 mPa·s. From the viewpoint of coatability and the like, the upper limit of the viscosity of the epoxidized vegetable oil according to the present invention is preferably 400 mPa·s, and more preferably 338 mPa·s. The E-type viscometer may be, for example, VISCOMETER TV-22 (manufactured by Toki Sangyo Co., Ltd.), and a CP1-type cone plate may be used.

[0020] The epoxidized vegetable oil according to the present invention preferably contains a compound represented by the above formula (1). By containing the compound represented by the above formula (1) in the epoxidized vegetable oil according to the present invention, it becomes easier to lower the dielectric constant of the cured product of the obtained curable resin composition for electronic devices.

[0021] Specific examples of the compound represented by the above formula (1) include 4,5-epoxycyclohexane-1,2-dicarboxylate di(9,10-epoxystearyl), 4,5-epoxycyclohexane-1,2-dicarboxylate di2-ethylhexyl, 3,4-diethyl-7-oxabicyclo[4.1.0]heptane-3,4-dicarboxylate, 3,4-bis(1-methylethyl)-7-oxabicyclo[4.1.0]heptane-3,4-dicarboxylate, 3,4-bis(1,1-dimethylethyl)-7-oxabicyclo[4.1.0]heptane-3,4-dicarboxylate, etc. Among them, 4,5-epoxycyclohexane-1,2-dicarboxylate di(9,10-epoxystearyl) and 4,5-epoxycyclohexane-1,2-dicarboxylate di2-ethylhexyl are preferred.

[0022] The preferred lower limit of the content of the epoxidized vegetable oil according to the present invention in 100 parts by mass of the curable resin is 10 parts by mass, and the preferred upper limit is 40 parts by mass. When the content of the epoxidized vegetable oil according to the present invention is 10 parts by mass or more, it becomes easier to lower the dielectric constant of the cured product of the curable resin composition for electronic devices obtained. When the content of the epoxidized vegetable oil according to the present invention is 40 parts by mass or less, the cured product of the curable resin composition for electronic devices obtained has better deformation resistance, toughness, and heat resistance.

[0023] The preferred lower limit of the content of the epoxidized vegetable oil according to the present invention in 100 parts by mass in total of the epoxidized vegetable oil according to the present invention and the alicyclic epoxy compound having two or more alicyclic epoxy groups in one molecule described below is 10 parts by mass, and the preferred upper limit is 40 parts by mass. When the content of the epoxidized vegetable oil according to the present invention is within this range, it becomes easier to lower the dielectric constant of the obtained cured product of the curable resin composition for electronic devices, and the cured product has better deformation resistance, toughness, and heat resistance.

[0024] The curable resin contains an alicyclic epoxy compound having two or more alicyclic epoxy groups in one molecule (hereinafter also referred to as a "bifunctional or higher alicyclic epoxy compound"). By containing the bifunctional or higher alicyclic epoxy compound, the curable resin composition for electronic devices of the present invention has excellent deformation resistance, toughness, and heat resistance when cured. In addition, even if a compound has a total of two or more of the alicyclic epoxy groups and epoxy groups other than the alicyclic epoxy groups in one molecule, it is not treated as the di- or higher functional alicyclic epoxy compound unless the number of the alicyclic epoxy groups in one molecule is two or more.

[0025] Examples of the alicyclic epoxy group contained in the di- or higher functional alicyclic epoxy compound include an epoxycyclohexyl group. The di- or higher functional alicyclic epoxy compound preferably has four or less alicyclic epoxy groups in one molecule. The di- or higher functional alicyclic epoxy compound may have, in addition to the alicyclic epoxy group, other functional groups such as epoxy groups other than the alicyclic epoxy group.

[0026] The di- or higher functional alicyclic epoxy compound preferably contains a di- or higher functional alicyclic epoxy compound having a silicone skeleton, since it becomes easier to reduce the dielectric constant of the obtained curable resin composition for electronic devices and the cured product has better heat resistance, and more preferably contains at least one selected from the group consisting of the compound represented by the above formula (2) and the compound represented by the above formula (3).

[0027] The curable resin may contain, as the difunctional or higher alicyclic epoxy compound, a difunctional or higher alicyclic epoxy compound other than the difunctional or higher alicyclic epoxy compound having a silicone skeleton.

[0028] Examples of the other difunctional or higher functional alicyclic epoxy compounds include 3,4-epoxycyclohexylmethyl(3,4-epoxy)cyclohexanecarboxylate, 4,4'-bis(1,2-epoxycyclohexane), and the like.

[0029] The preferred lower limit of the content of the difunctional or more alicyclic epoxy compound in 100 parts by mass of the curable resin is 60 parts by mass, and the preferred upper limit is 90 parts by mass. When the content of the difunctional or more alicyclic epoxy compound is 60 parts by mass or more, the curable resin composition for electronic devices of the present invention has a cured product that is more excellent in deformation resistance, toughness, and heat resistance. When the content of the difunctional or more alicyclic epoxy compound is 90 parts by mass or less, the curable resin composition for electronic devices of the present invention can more easily reduce the dielectric constant of the cured product.

[0030] The curable resin may contain other curable resins in addition to the epoxidized vegetable oil according to the present invention and the di- or higher functional alicyclic epoxy compound. Examples of the other curable resins include epoxy compounds other than the epoxidized vegetable oil according to the present invention and the di- or higher functional alicyclic epoxy compounds, oxetane compounds, (meth)acrylic compounds, and the like. In this specification, the term "(meth)acrylic" means acrylic or methacrylic.

[0031] Examples of the other epoxy compounds include epoxidized vegetable oils having a viscosity of 85 mPa s or less when measured using an E-type viscometer at 25°C and 100 rpm (hereinafter also referred to as "other epoxidized vegetable oils") and alicyclic epoxy compounds having one alicyclic epoxy group per molecule other than those corresponding to the epoxidized vegetable oils of the present invention. When the curable resin contains the other epoxidized vegetable oils, the content of the epoxidized vegetable oil according to the present invention in the total epoxidized vegetable oils is preferably 50 mass % or more.

[0032] Examples of the oxetane compound include 3-ethyl-3-(((3-ethyloxetan-3-yl)methoxy)methyl)oxetane, 1,4-bis(((3-ethyloxetan-3-yl)methoxy)methyl)benzene, bis((3-ethyloxetan-3-yl)methyl)isophthalate, and 3-ethyl-3-((2-ethylhexyl)oxy)oxetane.

[0033] Examples of the (meth)acrylic compound include 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, benzyl (meth)acrylate, trimethylolpropane tri(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, lauryl (meth)acrylate, and (meth)acrylic-modified silicone oil. In this specification, the term "(meth)acrylate" means acrylate or methacrylate.

[0034] The preferred lower limit of the total content of the curable resins in 100 parts by mass of the curable resin composition for electronic devices of the present invention is 85 parts by mass, and the preferred upper limit is 97 parts by mass. When the total content of the curable resins is within this range, the obtained curable resin composition for electronic devices has better curability and adhesiveness.

[0035] The curable resin composition for electronic devices of the present invention contains a polymerization initiator. The polymerization initiator preferably contains at least one selected from the group consisting of a photocationic polymerization initiator and a photoradical polymerization initiator, and more preferably contains a photocationic polymerization initiator.

[0036] The photocationic polymerization 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.

[0037] The anion portion of the ionic photoacid generating cationic photopolymerization initiator is, for example, BF4 - , PF6 - , SbF6 - , (BX4) - (wherein X represents a phenyl group substituted with at least two fluorine or trifluoromethyl groups). The anion moiety may be PF m (C n F 2n+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 type photocationic polymerization initiator include aromatic sulfonium salts, aromatic iodonium salts, aromatic diazonium salts, aromatic ammonium salts, (2,4-cyclopentadiene-1-yl)((1-methylethyl)benzene)-Fe salts, and the like, each of which has the anion moiety.

[0038] Examples of the aromatic sulfonium salt 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, and 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.

[0039] Examples of the aromatic iodonium salt 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.

[0040] Examples of the aromatic diazonium salt include phenyldiazonium hexafluorophosphate, phenyldiazonium hexafluoroantimonate, phenyldiazonium tetrafluoroborate, and phenyldiazonium tetrakis(pentafluorophenyl)borate.

[0041] 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.

[0042] Examples of the (2,4-cyclopentadiene-1-yl)((1-methylethyl)benzene)-Fe salt include (2,4-cyclopentadiene-1-yl)((1-methylethyl)benzene)-Fe(II) hexafluorophosphate, (2,4-cyclopentadiene-1-yl)((1-methylethyl)benzene)-Fe(II) hexafluoroantimonate, (2,4-cyclopentadiene-1-yl)((1-methylethyl)benzene)-Fe(II) tetrafluoroborate, and (2,4-cyclopentadiene-1-yl)((1-methylethyl)benzene)-Fe(II) tetrakis(pentafluorophenyl)borate.

[0043] Examples of the nonionic photoacid generating cationic photopolymerization initiator include nitrobenzyl esters, sulfonic acid derivatives, phosphoric acid esters, phenolsulfonic acid esters, diazonaphthoquinones, and N-hydroxyimide sulfonates.

[0044] Among the above-mentioned photocationic polymerization initiators, commercially available ones include, for example, photocationic polymerization initiators manufactured by Midori Chemical Industry Co., Ltd., photocationic polymerization initiators manufactured by Union Carbide Corporation, photocationic polymerization initiators manufactured by ADEKA Corporation, photocationic polymerization initiators manufactured by 3M Corporation, photocationic polymerization initiators manufactured by BASF Corporation, photocationic polymerization initiators manufactured by Solvay Corporation, and photocationic polymerization initiators manufactured by San-Apro Corporation. An example of the photocationic polymerization initiator manufactured by Midori Kagaku Co., Ltd. is DTS-200. Examples of the photocationic polymerization initiator manufactured by Union Carbide include UVI6990 and UVI6974. Examples of the photocationic polymerization initiator manufactured by ADEKA Corporation include SP-150 and SP-170. Examples of the photocationic polymerization initiator manufactured by 3M include FC-508 and FC-512. Examples of the cationic photopolymerization initiator manufactured by BASF include IRGACURE261 and IRGACURE290. An example of the photocationic polymerization initiator manufactured by Solvay is PI2074. Examples of the photocationic polymerization initiators manufactured by San-Apro include CPI-100P, CPI-200K, and CPI-210S.

[0045] Examples of the photoradical polymerization initiator include benzophenone compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, oxime ester compounds, benzoin ether compounds, and thioxanthone compounds. Specific examples of the photoradical polymerization initiator include 1-hydroxycyclohexyl phenyl ketone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 1,2-(dimethylamino)-2-((4-methylphenyl)methyl)-1-(4-(4-morpholinyl)phenyl)-1-butanone, 2,2-dimethoxy-1,2-diphenylethan-1-one, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2-methyl Examples of such benzoin derivatives include 1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 1-(4-(2-hydroxyethoxy)-phenyl)-2-hydroxy-2-methyl-1-propan-1-one, 1-(4-(phenylthio)phenyl)-1,2-octanedione 2-(O-benzoyloxime), 2,4,6-trimethylbenzoyldiphenylphosphine oxide, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether.

[0046] The polymerization initiator may include a thermal cationic polymerization initiator or a thermal radical polymerization initiator as long as the object of the present invention is not impaired. The polymerization initiators may be used alone or in combination of two or more kinds.

[0047] The content of the polymerization initiator is preferably 0.01 parts by mass at the lower limit and 10 parts by mass at the upper limit with respect to 100 parts by mass of the curable resin. When the content of the polymerization initiator is 0.01 parts by mass or more, the curable resin composition for electronic devices obtained has better curability. When the content of the polymerization initiator is 10 parts by mass or less, the curing reaction of the curable resin composition for electronic devices obtained does not become too fast, and the workability is better, and the cured product can be made more uniform. The more preferable lower limit of the content of the polymerization initiator is 0.05 parts by mass, and the more preferable upper limit is 5 parts by mass.

[0048] The curable resin composition for electronic devices of the present invention preferably further contains a sensitizer. The sensitizer has a role of further improving the polymerization initiation efficiency of the polymerization initiator and further accelerating the curing reaction of the curable resin composition for electronic devices of the present invention.

[0049] Examples of the sensitizer include anthracene compounds, thioxanthone compounds, 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. The anthracene compound includes, for example, 9,10-dibutoxyanthracene. The thioxanthone compound includes, for example, 2,4-diethylthioxanthone. These sensitizers may be used alone or in combination of two or more kinds.

[0050] The content of the sensitizer is preferably 0.01 parts by mass at the lower limit and 3 parts by mass at the upper limit with respect to 100 parts by mass of the curable resin. The sensitizer content of 0.01 parts by mass or more enhances the sensitizing effect. The sensitizer content of 3 parts by mass or less allows light to be transmitted to a deep portion without excessive absorption. The more preferred lower limit of the content of the sensitizer is 0.1 parts by mass, and the more preferred upper limit is 1 part by mass.

[0051] The curable resin composition for electronic devices of the present invention preferably further contains a surface conditioner. By containing the above-mentioned surface conditioner, the surface tension of the curable resin composition for electronic devices of the present invention can be adjusted to impart flatness to the coating film. Examples of the surface conditioner include a surfactant and a leveling agent.

[0052] Examples of the surface conditioner include silicone-based, acrylic-based, and fluorine-based ones. Among the above surface conditioners, commercially available ones include, for example, surface conditioners manufactured by Shin-Etsu Chemical Co., Ltd., surface conditioners manufactured by BYK Japan KK, and surface conditioners manufactured by AGC Seimi Chemical Co., Ltd. An example of the surface conditioner manufactured by Shin-Etsu Chemical Co., Ltd. is X-22-163A. Examples of the surface conditioner manufactured by BYK Japan include BYK-340 and BYK-345. An example of the surface conditioner manufactured by AGC Seimi Chemical Co., Ltd. is Surflon S-611.

[0053] The content of the surface conditioner is preferably 0.1 part by mass or less and 1 part by mass or less relative to 100 parts by mass of the curable resin. When the content of the surface conditioner is within this range, the surface tension of the obtained curable resin composition for electronic devices can be more easily adjusted.

[0054] The curable resin composition for electronic devices of the present invention preferably contains a stabilizer. By containing the stabilizer, the obtained curable resin composition for electronic devices has better storage stability.

[0055] Examples of the stabilizer include triethanolamine, benzylamine, triglycidyl-p-aminophenol, and the like. These stabilizers may be used alone or in combination of two or more kinds.

[0056] The content of the stabilizer is preferably 0.005 parts by mass or less and 0.05 parts by mass or less relative to 100 parts by mass of the curable resin. When the content of the stabilizer is within this range, the obtained curable resin composition for electronic devices has excellent storage stability while maintaining excellent curability.

[0057] The curable resin composition for electronic devices of the present invention may contain a heat curing agent within a range that does not impair the object of the present invention. Examples of the heat curing agent include hydrazide compounds, imidazole derivatives, acid anhydrides, dicyandiamide, guanidine derivatives, modified aliphatic polyamines, and addition products of various amines and epoxy resins. Examples of the hydrazide compound include 1,3-bis(hydrazinocarbonoethyl)-5-isopropylhydantoin, sebacic acid dihydrazide, isophthalic acid dihydrazide, adipic acid dihydrazide, and malonic acid dihydrazide. Examples of the imidazole derivatives include 1-cyanoethyl-2-phenylimidazole, N-(2-(2-methyl-1-imidazolyl)ethyl)urea, 2,4-diamino-6-(2'-methylimidazolyl-(1'))-ethyl-s-triazine, N,N'-bis(2-methyl-1-imidazolylethyl)urea, N,N'-(2-methyl-1-imidazolylethyl)-adipamide, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and 2-phenyl-4,5-dihydroxymethylimidazole. Examples of the acid anhydride include tetrahydrophthalic anhydride and ethylene glycol bis(anhydrotrimellitate). These heat curing agents may be used alone or in combination of two or more kinds.

[0058] Among the above-mentioned heat curing agents, examples of commercially available ones include a heat curing agent manufactured by Otsuka Chemical Co., Ltd. and a heat curing agent manufactured by Ajinomoto Fine-Techno Co., Ltd. Examples of the heat curing agents manufactured by Otsuka Chemical Co., Ltd. include SDH and ADH. Examples of the heat curing agents manufactured by Ajinomoto Fine-Techno Co., Inc. include Amicure VDH, Amicure VDH-J, and Amicure UDH.

[0059] The content of the heat curing agent is preferably 0.5 parts by mass at the lower limit and 30 parts by mass at the upper limit with respect to 100 parts by mass of the curable resin. By the content of the heat curing agent being within this range, the obtained curable resin composition for electronic devices has excellent heat curing properties while maintaining excellent storage stability. The more preferable lower limit of the content of the heat curing agent is 1 part by mass, and the more preferable upper limit is 15 parts by mass.

[0060] The curable resin composition for electronic devices of the present invention may further contain a silane coupling agent. The silane coupling agent has a role of improving adhesion between the curable resin composition for electronic devices of the present invention and a substrate or the like.

[0061] Examples of the silane coupling agent include 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatepropyltrimethoxysilane. These silane coupling agents may be used alone or in combination of two or more kinds.

[0062] The content of the silane coupling agent is preferably 0.1 parts by mass at the lower limit and 10 parts by mass at the upper limit with respect to 100 parts by mass of the curable resin. By the content of the silane coupling agent being within this range, the effect of improving the adhesiveness of the obtained curable resin composition for electronic devices is excellent while suppressing the bleeding out caused by the excess silane coupling agent. The more preferable lower limit of the content of the silane coupling agent is 0.5 parts by mass, and the more preferable upper limit is 5 parts by mass.

[0063] 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.

[0064] The above-mentioned curing retarder includes, for example, a polyether compound. Examples of the polyether compound include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, crown ether compounds, etc. Among these, crown ether compounds are preferred.

[0065] The content of the curing retarder is preferably 0.05 parts by mass at the lower limit and 5.0 parts by mass at the upper limit with respect to 100 parts by mass of the curable resin. By the content of the curing retarder being within this range, the retardation effect can be more effectively exhibited while suppressing the generation of outgassing when curing the obtained curable resin composition for electronic devices. The more preferred lower limit of the content of the curing retarder is 0.1 parts by mass, and the more preferred upper limit is 3.0 parts by mass.

[0066] 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.

[0067] The compound that reacts with the acid generated in the composition includes a substance that neutralizes the acid, such as a carbonate or hydrogen carbonate of an alkali metal or an alkaline earth metal, etc. Specific examples of the compound that can be used include calcium carbonate, calcium hydrogen carbonate, sodium carbonate, sodium hydrogen carbonate, etc.

[0068] The ion exchange resin may be of any of the cation exchange type, anion exchange type and amphoteric ion exchange type, with the cation exchange type and amphoteric ion exchange type being particularly suitable for adsorbing chloride ions.

[0069] Furthermore, the curable resin composition for electronic devices of the present invention may contain various known additives such as a reinforcing agent, a softener, a plasticizer, a viscosity modifier, and an ultraviolet absorbing agent, as necessary.

[0070] Examples of a method for producing the curable resin composition for electronic devices of the present invention include a method in which a curable resin, a polymerization initiator, and an additive such as a sensitizer, which is added as necessary, are mixed using a mixer such as a homodisper, a homomixer, a universal mixer, a planetary mixer, a kneader, or a three-roll mill.

[0071] The curable resin composition for electronic devices of the present invention has a viscosity, measured using an E-type viscometer at 25°C and 100 rpm, of preferably 40 mPa·s as a lower limit and 110 mPa·s as an upper limit. When the viscosity at 25°C is within this range, the curable resin composition for electronic devices of the present invention has better coatability. A more preferable lower limit of the viscosity of the curable resin composition for electronic devices of the present invention is 55 mPa·s.

[0072] The curable resin composition for electronic devices of the present invention has a preferred upper limit of the dielectric constant of the cured product of the curable resin composition for electronic devices measured under conditions of 25° C. and 1 GHz of 3.5. Since the dielectric constant of the cured product is 3.5 or less, the curable resin composition for electronic devices of the present invention can be suitably used as an adhesive for electronic devices such as an adhesive for touch panels and a solder resist for circuit boards, or as a coating agent for electronic devices. The more preferred upper limit of the dielectric constant of the cured product is 2.8, and the even more preferred upper limit is 2.6. Further, although there is no particular preferred lower limit for the dielectric constant of the cured product, the substantial lower limit is 2.2. The above-mentioned "dielectric constant" can be measured using a dielectric constant measuring device. For example, the cured product for measuring the dielectric constant is prepared by applying the curable resin composition for electronic devices to a thickness of 100 μm on a PET film, and then irradiating the cured product with ultraviolet light having a wavelength of 395 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 at 3000mJ / cm 2 It can be obtained by irradiation.

[0073] The curable resin composition for electronic devices of the present invention has a preferred lower limit of the glass transition temperature of the cured product of the curable resin composition for electronic devices of 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 excellent heat resistance. The preferred lower limit of the glass transition temperature of the cured product is 80° C. There is no particular upper limit to 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 a 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 measuring the glass transition temperature can be obtained, for example, by the following method. That is, the curable resin composition for electronic devices was applied onto a PET film so that the thickness of the cured product was 0.3 mm, and then the film was exposed to ultraviolet light with a wavelength of 395 nm and an illuminance of 1000 mW / cm using an LED UV lamp in a dry chamber with a dew point of -50°C or less. 2 at 3000mJ / cm 2 It can be obtained by irradiation.

[0074] The curable resin composition for electronic devices of the present invention is used as an adhesive for electronic devices such as an adhesive for touch panels and a solder resist for circuit boards, or as a coating agent for electronic devices. In particular, the curable resin composition for electronic devices of the present invention is suitably used for a display element equipped with a capacitive touch panel, and is particularly suitably used as a sealant for an organic EL display element. Effect of the Invention

[0075] According to the present invention, it is possible to provide a curable resin composition for electronic devices which provides a cured product having a low dielectric constant and excellent deformation resistance and toughness. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0076] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0077] (Examples 1 to 5, Comparative Examples 1 to 6) The curable resin compositions for electronic devices of Examples 1 to 5 and Comparative Examples 1 to 6 were prepared by uniformly mixing and stirring the materials at a stirring speed of 3000 rpm using a Homo Disper type stirring mixer according to the compounding ratios shown in Table 1. As the Homo Disper type stirring mixer, a Homo Disper L model (manufactured by Primix Corporation) was used. The viscosity of each of the epoxidized vegetable oils used in Examples 1 to 5 and Comparative Examples 1, 2, 5, and 6 was measured using an E-type viscometer with a CP1 cone plate at 25°C and 100 rpm. The E-type viscometer used was a VISCOMETER TV-22 (manufactured by Toki Sangyo Co., Ltd.). The results are shown in Table 1. In addition, "X-22-169" in Table 1 corresponds to R 3 is a methyl group, R 4 is a dimethylene group and n is 0.

[0078] <Evaluation> The curable resin compositions for electronic devices obtained in the examples and comparative examples were evaluated as follows. The results are shown in Table 1. In addition, the curable resin compositions for electronic devices obtained in Comparative Examples 4 and 6 could not be cured under the conditions described below, so the evaluations of "(dielectric characteristics of the cured product)", "(deformation resistance and toughness of the cured product)", and "(heat resistance of the cured product)" were not performed.

[0079] (Viscosity of Curable Resin Composition for Electronic Devices) The viscosity of each of the obtained curable resin compositions for electronic devices was measured using an E-type viscometer with a CP1 type cone plate at 25° C. and 100 rpm. The E-type viscometer used was a VISCOMETER TV-22 (manufactured by Toki Sangyo Co., Ltd.).

[0080] (Dielectric properties of the cured product) Each of the obtained curable resin compositions for electronic devices was applied to a PET film to a thickness of 100 μm, and then the film was exposed to ultraviolet light of 395 nm wavelength at an illuminance of 1000 mW / cm using an LED UV lamp in a dry chamber with a dew point of -50°C or less. 2 at 3000mJ / cm 2 A cured film was obtained by irradiating the sample. The LED UV lamp used was an SQ series (manufactured by Quark Technology). Then, gold electrodes were vacuum-deposited on both sides of the cured film in a 0.1 μm thick circular shape with a diameter of 2 cm, facing each other, to prepare a test piece for dielectric constant measurement. The dielectric constant of the obtained test piece was measured at 25° C. and 1 GHz using a dielectric constant measurement device. The dielectric constant measurement device used was a 1260-type impedance analyzer (manufactured by Solartron) and a 1296-type dielectric constant measurement interface (manufactured by Solartron). The dielectric properties of the cured products were evaluated as follows: when the obtained dielectric constant was 2.6 or less, it was marked "◎", when it was more than 2.6 and less than 2.8, it was marked "◯", when it was more than 2.8 and less than 3.5, it was marked "△", and when it was more than 3.5, it was marked "X".

[0081] (Deformation resistance and toughness of the cured product) 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 of 395 nm in wavelength and 1000 mW / cm illuminance using an LED UV lamp in a dry chamber with a dew point of -50°C or less. 2 at 3000mJ / cm 2 The resulting cured product, 20 mm long, 5 mm wide and 0.3 mm thick, was peeled off from the PET film to prepare a test piece. The obtained test pieces were visually observed, and the deformation resistance and toughness of the cured products were evaluated by assigning an "O" to cases where no deformation or cracking was observed and an "X" to cases where deformation or cracking was observed.

[0082] (Heat resistance of the cured product) 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 of 395 nm in wavelength and 1000 mW / cm illuminance using an LED UV lamp in a dry chamber with a dew point of -50°C or less. 2 at 3000mJ / cm 2 The cured product was irradiated with light. This resulted in a cured product with a length of 20 mm, width of 5 mm, and thickness of 0.3 mm. The LED UV lamp used was an SQ series (manufactured by Quark Technology). The dynamic viscoelasticity of the resulting cured product was measured using a dynamic viscoelasticity measuring device (manufactured by IT Measurement and Control, "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) was at its maximum was determined as the glass transition temperature. The heat resistance of the cured product was evaluated based on the following criteria: if the obtained glass transition temperature was 80°C or higher, it was marked as "○", if it was 50°C or higher and less than 80°C, it was marked as "△", and if it was less than 50°C, it was marked as "×".

[0083] [Table 1] [Industrial Applicability]

[0084] According to the present invention, it is possible to provide a curable resin composition for electronic devices which provides a cured product having a low dielectric constant and excellent deformation resistance and toughness.

Claims

1. A curable resin composition for electronic devices, comprising a curable resin and a polymerization initiator, The curable resin contains an epoxidized vegetable oil and an alicyclic epoxy compound having two or more alicyclic epoxy groups in one molecule, The epoxidized vegetable oil has a viscosity of more than 85 mPa·s measured at 25° C. and 100 rpm using an E-type viscometer. A curable resin composition for electronic devices comprising:

2. The curable resin composition for electronic devices according to claim 1 , wherein the epoxidized vegetable oil contains a compound represented by the following formula (1): 【Chemistry 1】 In formula (1), R １ and R ２ are each independently a linear or branched organic group having 1 to 20 carbon atoms.

3. 3. The curable resin composition for electronic devices according to claim 1, wherein a content of the epoxidized vegetable oil is 10 parts by mass or more and 40 parts by mass or less in a total of 100 parts by mass of the epoxidized vegetable oil and the alicyclic epoxy compound having two or more alicyclic epoxy groups in one molecule.

4. The curable resin composition for electronic devices according to claim 1 or 2, wherein the alicyclic epoxy compound having two or more alicyclic epoxy groups in one molecule includes at least one selected from the group consisting of a compound represented by the following formula (2) and a compound represented by the following formula (3): 【Chemistry 2】 In formula (2), R ３ are each independently an alkyl group having 1 to 10 carbon atoms; R ４ each independently represents a bond or an alkylene group having 1 to 6 carbon atoms, and n represents an integer of 0 to 1,000. 【Chemistry 3】 In formula (3), R ５ are each independently an alkyl group having 1 to 10 carbon atoms; R ６ is a bond or an alkylene group having 1 to 6 carbon atoms; R ７ are each independently an alkyl group having 1 to 10 carbon atoms, a group represented by the following formula (4-1), a group represented by the following formula (4-2), a group represented by the following formula (4-3), or a group represented by the following formula (4-4). In formula (3), l represents an integer of 0 to 1000, and m represents an integer of 1 to 100. ７ When none of the groups is a group represented by the following formula (4-1), m represents an integer of 2 or more and 100 or less. 【Chemistry 4】 In formulas (4-1) to (4-4), R ８ represents a bond or an alkylene group having 1 to 6 carbon atoms; in formula (4-3), R ９ represents hydrogen or an alkyl group having 1 to 6 carbon atoms; R １０ represents a bond or a methylene group, and in formula (4-4), R １１ represents hydrogen or a methyl group.

5. The curable resin composition for electronic devices according to claim 1 or 2, wherein the polymerization initiator comprises at least one selected from the group consisting of a photocationic polymerization initiator and a photoradical polymerization initiator.

6. The curable resin composition for electronic devices according to claim 1 or 2, further comprising a sensitizer.

7. The curable resin composition for electronic devices according to claim 1 or 2, further comprising a surface conditioner.

8. 3. The curable resin composition for electronic devices according to claim 1, having a viscosity of 40 mPa·s or more and 110 mPa·s or less, measured using an E-type viscometer at 25° C. and 100 rpm.

9. 3. The curable resin composition for electronic devices according to claim 1 or 2, wherein the dielectric constant of a cured product of the curable resin composition for electronic devices is 3.5 or less, as measured under conditions of 25° C. and 1 GHz.

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