Resin composition for display elements

Abstract

The present invention provides a resin composition for display elements in which the cured product exhibits excellent low dielectric properties and can suppress odor. [Solution] A resin composition for a display element containing a curable resin and a photocationic polymerization initiator, wherein the curable resin comprises a curable resin A represented by the following formula (1) and a curable resin B having a boiling point of 260°C or higher, and the content of the curable resin A in 100 parts by mass of the curable resin is 30 parts by mass or more and 90 parts by mass or less. [C1] TIFF2026061580000014.tif44156 In formula (1), R 1 and R 2 Each of these is independently either a hydrogen atom or a methyl group.

Description

[Technical Field]

[0001] This invention relates to a resin composition for display elements. [Background technology]

[0002] Touch panels are used in electronic devices such as mobile phones, smartphones, car navigation systems, and personal computers, and among them, capacitive touch panels are rapidly gaining popularity due to their superior functionality. In particular, in recent years, development of display elements such as organic EL display elements equipped with capacitive touch panels has progressed. For resin compositions for display elements used in sealing display elements equipped with touch panels, there is a need for materials that have appropriate viscosity, excellent coatability, and excellent curability. Furthermore, with the recent trend towards thinner and larger capacitive touch panels, in order to prevent a decrease in the response speed of the touch panel, resin compositions for display elements are also required to have low dielectric properties such as low dielectric constant and low dielectric loss tangent. As a resin composition for display elements with excellent photocurability and low dielectric properties, for example, Patent Document 1 discloses a composition containing a vinyl monomer such as divinylbenzene and a photoacid generator (photocationic polymerization initiator). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-190428 [Overview of the project] [Problems that the invention aims to solve]

[0004] Resin compositions using vinyl monomers, such as those disclosed in Patent Document 1, are expected to be used as encapsulants for display elements, particularly those requiring low dielectric properties. However, many of these vinyl monomers are highly volatile, leading to problems such as outgassing and associated odors.

[0005] An object of the present invention is to provide a resin composition for a display element in which a cured product has excellent low dielectric properties and can suppress odor.

Means for Solving the Problems

[0006] The present disclosure 1 is a resin composition for a display element containing a curable resin and a photo cationic polymerization initiator, wherein the curable resin includes a curable resin A represented by the following formula (1) and a curable resin B having a boiling point of 260°C or higher, and the content of the curable resin A in 100 parts by mass of the curable resin is 30 parts by mass or more and 90 parts by mass or less. The present disclosure 2 is the resin composition for a display element according to the present disclosure 1, wherein the curable resin B has at least one structure selected from the group consisting of a styrene skeleton, an alicyclic or non-alicyclic epoxy group, and an oxetanyl group. The present disclosure 3 is the resin composition for a display element according to the present disclosure 1 or 2, further containing a viscosity modifier. The present disclosure 4 is the resin composition for a display element according to the present disclosure 1, 2, or 3, having a viscosity of 1 mPa·s or more and 30 mPa·s or less measured under the conditions of 25°C and 10 rpm using an E-type viscometer. The present disclosure 5 is the resin composition for a display element according to the present disclosure 1, 2, 3, or 4, having a dielectric constant of the cured product measured under the conditions of 25°C and 100 kHz of 3.0 or less.

[0007]

Chemical formula

[0008] In formula (1), R 1 and R 2 are each independently a hydrogen atom or a methyl group. The present invention will be described in detail below.

[0009] The inventors investigated using a combination of a curable resin A having a specific structure and a curable resin B having a boiling point below a specific temperature, and setting the content of curable resin A within a specific range. As a result, they found that it is possible to obtain a resin composition for display elements in which the cured product has excellent low dielectric properties and can suppress odor, thus completing the present invention.

[0010] The resin composition for display elements of the present invention contains a curable resin. The above curable resin includes curable resin A represented by formula (1) above and curable resin B described later. By using curable resin A and curable resin B described later in combination, and by setting the content of curable resin A within the range described later, the resin composition for display elements of the present invention will have a cured product that is excellent in low dielectric properties and can suppress odor.

[0011] Examples of the curable resin A mentioned above include 1,2-divinylbenzene, 1,3-divinylbenzene, 1,4-divinylbenzene, 1,2-diisopropenylbenzene, 1,3-diisopropenylbenzene, and 1,4-diisopropenylbenzene. Among these, 1,3-diisopropenylbenzene is preferred because the resulting resin composition for display elements exhibits superior curability and odor suppression without impairing the low dielectric properties of the cured product.

[0012] The lower limit of the content of the curable resin A in 100 parts by mass of the above curable resin is 30 parts by mass, and the upper limit is 90 parts by mass. When the content of curable resin A is 30 parts by mass or more, the resin composition for display elements of the present invention has excellent curability and the cured product has excellent low dielectric properties. When the content of curable resin A is 90 parts by mass or less, the resin composition for display elements of the present invention can suppress odor. The preferred lower limit of the content of curable resin A is 60 parts by mass, and the preferred upper limit is 80 parts by mass.

[0013] The curable resin B described above has a boiling point of 260°C or higher. By using such curable resin B in combination with curable resin A, the resin composition for display elements of the present invention can suppress odor. The preferred lower limit of the boiling point of the curable resin B is 300°C. In this specification, the term "boiling point" refers to the value measured under conditions of 101 kPa, or the value converted to 101 kPa using a boiling point conversion chart or similar.

[0014] The curable resin B is preferably solid at 25°C. The fact that the curable resin B is solid at 25°C results in a resin composition for display elements that exhibits superior odor suppression.

[0015] The curable resin B described above preferably has at least one structure selected from the group consisting of a styrene skeleton, an alicyclic or non-alicyclic epoxy group, and an oxetanyl group. Having at least one structure selected from the group consisting of a styrene skeleton, an alicyclic or non-alicyclic epoxy group, and an oxetanyl group results in a display element resin composition with excellent curability and low dielectric properties. In particular, from the viewpoint of low dielectric properties, the curable resin B is preferably composed of a styrene skeleton.

[0016] Examples of the curable resin B mentioned above include, for example, 1,3-bis(1-phenylethenyl)benzene (solid at 25°C, boiling point 260°C or higher), compounds represented by the following formula (2) (boiling point 260°C or higher), compounds represented by the following formula (3) (boiling point 260°C or higher), compounds represented by the following formula (4) (boiling point 260°C or higher), compounds represented by the following formula (6) (boiling point 260°C or higher), compounds represented by the following formula (7) (boiling point 260°C or higher), compounds represented by the following formula (8) (boiling point 260°C or higher), compounds represented by the following formula (9) (boiling point 260°C or higher), compounds represented by the following formula (10) (boiling point 260°C or higher), compounds represented by the following formula (11) (boiling point 260°C or higher), and so on.

[0017] [Chemical formula]

[0018] In formula (2), R 3 is an alkylene group having 1 to 20 carbon atoms.

[0019] [Chemical formula]

[0020] In formula (3), R 4 are each independently an alkyl group having 1 to 10 carbon atoms, R 5 are each independently a bond or an alkylene group having 1 to 6 carbon atoms, and n represents an integer of 0 or more and 1000 or less.

[0021] [Chemical formula]

[0022] In formula (4), R 6 are each independently an alkyl group having 1 to 10 carbon atoms, R 7 is a bond or an alkylene group having 1 to 6 carbon atoms, and R 8 are each independently an alkyl group having 1 to 10 carbon atoms, a group represented by the following formula (5-1), a group represented by the following formula (5-2), a group represented by the following formula (5-3), or a group represented by the following formula (5-4). In formula (4), l represents an integer of 0 or more and 1000 or less, and m represents an integer of 1 or more and 100 or less. However, when none of R 8 is a group represented by the following formula (5-1), m represents an integer of 2 or more and 100 or less.

[0023] [Chemical formula]

[0024] In formulas (5-1) to (5-4), R 9R is a bond or an alkylene group having 1 to 6 carbon atoms, in formula (5-3), 10 R is hydrogen or an alkyl group having 1 to 6 carbon atoms. 11 R is a bond or methylene group, and in formula (5-4), 12 is either a hydrogen atom or a methyl group. In formulas (5-1) to (5-4), * indicates a bond position.

[0025] [ka]

[0026] In formula (6), R 13 ~R 30 Each of these is independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms.

[0027] [ka]

[0028] In formula (7), R 31 ~R 42 Each of these is independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms.

[0029] [ka]

[0030] In formula (8), R 43 ~R 60 Each of these is independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms.

[0031] [ka]

[0032] In formula (9), R61 ~R 78 Each of these is independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms.

[0033] [ka]

[0034] In formula (10), R 79 ~R 92 Each of these is independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms.

[0035] [ka]

[0036] In formula (11), R 93 and R 94 Each of these is an alkyl group having between 1 and 20 carbon atoms, and k represents an integer between 0 and 2, inclusive.

[0037] In particular, the curable resin B mentioned above includes 1,3-bis(1-phenylethenyl)benzene (solid at 25°C, boiling point above 260°C), α-methylstyrene dimer (boiling point 301°C), and R in formula (3) above. 4 is a methyl group, R 5 A compound in which is a dimethylene group and n is 0 (boiling point of 260°C or higher), and R in formula (4) above. 6 is a methyl group, R 7 is a dimethylene group, R 8 A compound in which is a methyl group, l is 0, and m is 1 (boiling point of 260°C or higher) is preferred.

[0038] The preferred lower limit for the content of the curable resin B in 100 parts by mass of the curable resin is 10 parts by mass, and the preferred upper limit is 70 parts by mass. When the content of the curable resin B is within this range, the resulting resin composition for display elements exhibits superior curability, odor suppression, and low dielectric properties of the cured product. A more preferred lower limit for the content of the curable resin B is 20 parts by mass, and a more preferred upper limit is 40 parts by mass.

[0039] The above-mentioned curable resin may include other curable resins other than curable resin A and curable resin B, to the extent that they do not hinder the objectives of the present invention. Examples of the above-mentioned other curable resins include epoxy compounds with a boiling point of less than 260°C, oxetane compounds with a boiling point of less than 260°C, vinyl ether compounds with a boiling point of less than 260°C, and (meth)acrylic compounds with a boiling point of less than 260°C. In this specification, "(meth)acrylic" means acrylic or methacrylic.

[0040] The preferred lower limit of the total content of the curable resin in 100 parts by mass of the resin composition for display elements of the present invention is 85 parts by mass, and the preferred upper limit is 99 parts by mass. Having the total content of the curable resin within this range results in a display element resin composition with superior curability and adhesion.

[0041] The resin composition for display elements of the present invention contains a photocationic polymerization initiator. The above-mentioned photocationic polymerization initiator is not particularly limited as long as it generates a protonic acid or a Lewis acid upon light irradiation, and may be an ionic photoacid generating type or a nonionic photoacid generating type.

[0042] For example, the anionic portion of the above-mentioned ionic photoacid-generating photocationic polymerization initiator is BF4. - PF6 - SbF6 - (BX4) -(However, X represents a phenyl group substituted with at least two fluorine or trifluoromethyl groups), etc. Also, the above anion portion is PF m (C n F 2n+1 ) 6-m - (However, m is an integer between 0 and 5, and n is an integer between 1 and 6.) Examples of the above-mentioned ionic photoacid-generating photocationic polymerization initiators include aromatic sulfonium salts, aromatic iodonium salts, aromatic diazonium salts, aromatic ammonium salts, and (2,4-cyclopentadiene-1-yl)((1-methylethyl)benzene)-Fe salts, which have the above-mentioned anionic moiety.

[0043] Examples of the above 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, and triphenylsulfonium hexafluorophosphate. Examples include oroantimonate, triphenylsulfonium tetrafluoroborate, triphenylsulfonium tetrakis(pentafluorophenyl)borate, triarylsulfonium 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.

[0044] Examples of the above 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.

[0045] Examples of the above-mentioned aromatic diazonium salts include phenyldiazonium hexafluorophosphate, phenyldiazonium hexafluoroantimonate, phenyldiazonium tetrafluoroborate, and phenyldiazonium tetrakis(pentafluorophenyl)borate.

[0046] Examples of the above aromatic ammonium salts 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.

[0047] Examples of the above (2,4-cyclopentadiene-1-yl)((1-methylethyl)benzene)-Fe salts 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.

[0048] Examples of the above-mentioned nonionic photoacid-generating photocationic polymerization initiators include nitrobenzyl esters, sulfonic acid derivatives, phosphate esters, phenolsulfonic acid esters, diazonaphthoquinone, and N-hydroxyimidosulfonate.

[0049] Examples of commercially available photocationic polymerization initiators include those manufactured by Midori Chemical Co., Ltd., Union Carbide Corporation, ADEKA Corporation, 3M Corporation, BASF Corporation, Solvay Corporation, and Sunapro Corporation. Examples of photocationic polymerization initiators manufactured by Midori Chemical Co., Ltd. include DTS-200. Examples of photocationic polymerization initiators from Union Carbide include UVI6990 and UVI6974. Examples of the photocationic polymerization initiators manufactured by ADEKA mentioned above include SP-150 and SP-170. Examples of the 3M photocationic polymerization initiators mentioned above include FC-508 and FC-512. Examples of photocationic polymerization initiators manufactured by BASF include IRGACURE261 and IRGACURE290. Examples of photocationic polymerization initiators from Solvay include PI2074. Examples of photocationic polymerization initiators manufactured by Sunapro include CPI-100P, CPI-200K, and CPI-210S.

[0050] The preferred lower limit for the content of the above-mentioned photocationic polymerization initiator is 0.01 parts by mass and the preferred upper limit is 10 parts by mass per 100 parts by mass of the above-mentioned curable resin. When the content of the above-mentioned photocationic polymerization initiator is 0.01 parts by mass or more, the resulting resin composition for display elements will have superior photocurability. When the content of the above-mentioned photocationic polymerization initiator is 10 parts by mass or less, the curing reaction of the resulting resin composition for display elements will not be too fast, resulting in superior workability and a more uniform cured product. A more preferred lower limit for the content of the above-mentioned photocationic polymerization initiator is 0.05 parts by mass and a more preferred upper limit is 5 parts by mass.

[0051] The resin composition for display elements of the present invention preferably further contains a sensitizer. The sensitizer has the role of further improving the polymerization initiation efficiency of the photocationic polymerization initiator and further promoting the curing reaction of the resin composition for display elements of the present invention.

[0052] Examples of the sensitizers mentioned above include anthracene compounds, thioxanthone compounds, 2,2-dimethoxy-1,2-diphenylethane-1-one, benzophenone, 2,4-dichlorobenzophenone, o-methyl benzoylbenzoate, 4,4'-bis(dimethylamino)benzophenone, and 4-benzoyl-4'-methyldiphenyl sulfide. Examples of the above anthracene compounds include 9,10-dibutoxyanthracene. Examples of the thioxanthone compounds mentioned above include 2,4-diethylthioxanthone.

[0053] The preferred lower limit for the content of the above-mentioned sensitizer is 0.01 parts by mass and the preferred upper limit is 3 parts by mass per 100 parts by mass of the above-mentioned curable resin. When the content of the above-mentioned sensitizer is 0.01 parts by mass or more, the sensitizing effect is more pronounced. When the content of the above-mentioned sensitizer is 3 parts by mass or less, light can be transmitted to the depths without absorption becoming too large. A more preferred lower limit for the content of the above-mentioned sensitizer is 0.1 parts by mass and a more preferred upper limit is 1 part by mass.

[0054] The resin composition for display elements of the present invention preferably further contains a viscosity modifier. By including the viscosity modifier, the resulting resin composition for display elements has superior coatability.

[0055] A thermoplastic resin is preferably used as the viscosity modifier. The above thermoplastic resin has a preferred lower limit of melt mass flow rate (MFR) of 5.0 g / 10 min. A thermoplastic resin with an MFR of 5.0 g / 10 min or higher results in a resin composition for display elements with superior coatability. Furthermore, while there is no particular preferred upper limit for the MFR of the above thermoplastic resin, the practical upper limit is 30 g / 10 min. In this specification, "melt mass flow rate (MFR)" refers to an index indicating fluidity during melting, and means a value measured in accordance with JIS K 7210.

[0056] Examples of the thermoplastic resins mentioned above include styrene-ethylene-butylene-styrene (SEBS) copolymer, methylstyrene-(ethylene / butylene)-methylstyrene copolymer, styrene-(ethylene-ethylene / propylene)-styrene copolymer, methylstyrene-(ethylene-ethylene / propylene)-methylstyrene copolymer, styrene-butadiene-styrene copolymer, and hydrogenated styrene-isoprene-styrene copolymer. Among these, SEBS copolymer is preferred.

[0057] The content of the viscosity modifier described above is preferably 1.5 parts by mass and preferably 5 parts by mass per 100 parts by mass of the curable resin. Having the viscosity modifier content within this range results in a display element resin composition with superior coatability.

[0058] The resin composition for display elements of the present invention preferably further contains a surface modifier. By including the above-mentioned surface modifier, the surface tension of the resin composition for display elements of the present invention can be adjusted to impart flatness to the coating film. Examples of the surface modifiers mentioned above include surfactants and leveling agents.

[0059] Examples of the surface modifiers mentioned above include silicone-based, acrylic-based, and fluorine-based materials. Examples of commercially available surface conditioning agents include those manufactured by Bic Chemie Co., Ltd. and AGC Seimi Chemical Co., Ltd. Examples of surface conditioning agents manufactured by BYK-Chemie include BYK-330, BYK-340, and BYK-345. Examples of surface conditioning agents manufactured by AGC Seimi Chemical Co., Ltd. include Surflon S-611.

[0060] The preferred lower limit of the content of the surface modifier is 0.1 parts by mass and the preferred upper limit is 1 part by mass per 100 parts by mass of the curable resin. Having the surface modifier content within this range makes it easier to adjust the surface tension of the resulting resin composition for display elements. A more preferred lower limit for the surface modifier content is 0.3 parts by mass and a more preferred upper limit is 0.8 parts by mass.

[0061] The resin composition for display elements of the present invention may contain a stabilizer. By including the above-mentioned stabilizer, the resulting resin composition for display elements will have even better storage stability.

[0062] Examples of the above-mentioned stabilizers include triethanolamine, benzylamine, and triglycidyl-p-aminophenol.

[0063] The preferred lower limit for the content of the above-mentioned stabilizer is 0.005 parts by mass and the preferred upper limit is 0.05 parts by mass per 100 parts by mass of the above-mentioned curable resin. By having the content of the above-mentioned stabilizer within this range, the resulting resin composition for display elements will have superior storage stability while maintaining excellent curability.

[0064] The resin composition for display elements of the present invention may contain a thermosetting agent to the extent that it does not hinder the objectives of the present invention. Examples of the above-mentioned thermosetting agents include hydrazide compounds, imidazole derivatives, acid anhydrides, dicyandiamides, guanidine derivatives, modified aliphatic polyamines, and addition products of epoxy resins with various amines. Examples of the above-mentioned hydrazide compounds include 1,3-bis(hydrazinocarbonoethyl)-5-isopropylhydantoin, sebacate dihydrazide, isophthalic acid dihydrazide, adipic acid dihydrazide, and malonic acid dihydrazide. Examples of the above-mentioned 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)-adipoamide, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and 2-phenyl-4,5-dihydroxymethylimidazole. Examples of the above-mentioned acid anhydrides include tetrahydrophthalic anhydride and ethylene glycol bis(anhydrotrimellitate).

[0065] Examples of commercially available thermosetting agents include those manufactured by Otsuka Chemical Co., Ltd. and those manufactured by Ajinomoto Fine Techno Co., Ltd. Examples of thermosetting agents manufactured by Otsuka Chemical Co., Ltd. include SDH and ADH. Examples of the thermosetting agents manufactured by Ajinomoto Fine Techno Co., Ltd. include Amicure VDH, Amicure VDH-J, and Amicure UDH.

[0066] The preferred lower limit for the content of the above-mentioned thermosetting agent is 0.5 parts by mass and the preferred upper limit is 30 parts by mass per 100 parts by mass of the above-mentioned curable resin. When the content of the above-mentioned thermosetting agent is within this range, the resulting resin composition for display elements maintains excellent storage stability while exhibiting superior thermosetting properties. A more preferred lower limit for the content of the above-mentioned thermosetting agent is 1 part by mass and a more preferred upper limit is 15 parts by mass.

[0067] The resin composition for display elements of the present invention may further contain a silane coupling agent. The silane coupling agent serves to improve the adhesion between the resin composition for display elements of the present invention and a substrate or the like.

[0068] Examples of the silane coupling agents mentioned above include 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatetopropyltrimethoxysilane.

[0069] The preferred lower limit of the silane coupling agent content is 0.1 parts by mass and the preferred upper limit is 10 parts by mass per 100 parts by mass of the curable resin. This range of silane coupling agent content provides superior effectiveness in improving the adhesion of the resulting resin composition for display elements while suppressing bleed-out due to excess silane coupling agent. A more preferred lower limit for the silane coupling agent content is 0.5 parts by mass and a more preferred upper limit is 5 parts by mass.

[0070] The resin composition for display elements of the present invention may contain a curing retarder. By including the curing retarder, the pot life of the resulting resin composition for display elements can be extended.

[0071] Examples of the curing retarders mentioned above include polyether compounds. Examples of the polyether compounds mentioned above include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and crown ether compounds. Among these, crown ether compounds are preferred.

[0072] The preferred lower limit of the curing retarder content is 0.05 parts by mass and the preferred upper limit is 5.0 parts by mass per 100 parts by mass of the curable resin. This curing retarder content range allows for a greater delaying effect while suppressing outgassing during the curing of the resulting resin composition for display elements. A more preferred lower limit for the curing retarder content is 0.1 parts by mass and a more preferred upper limit is 3.0 parts by mass.

[0073] The resin composition for display elements of the present invention may contain a compound or ion exchange resin that reacts with the acid generated in the composition, to the extent that it does not hinder the objectives of the present invention.

[0074] Compounds that react with the acid generated in the above composition include substances that neutralize the acid, such as alkali metal or alkaline earth metal carbonates or bicarbonates. Specifically, calcium carbonate, calcium bicarbonate, sodium carbonate, sodium bicarbonate, etc., can be used.

[0075] As the ion exchange resin mentioned above, any of the following types can be used: cation exchange type, anion exchange type, or both ion exchange type. However, a cation exchange type or both ion exchange type that can adsorb chloride ions is particularly preferred.

[0076] Furthermore, the resin composition for display elements of the present invention may optionally contain various known additives such as fillers, reinforcing agents, softeners, plasticizers, and ultraviolet absorbers.

[0077] Methods for producing the resin composition for display elements of the present invention include, for example, a method of mixing a curable resin, a photocationic polymerization initiator, and additives such as sensitizers added as needed, using a mixer such as a homodisperser, homomixer, universal mixer, planetary mixer, kneader, or three-roll mixer.

[0078] The resin composition for display elements of the present invention has a preferred lower limit of 1 mPa·s and a preferred upper limit of 30 mPa·s for viscosity, as measured using an E-type viscometer at 25°C and 10 rpm. Having the viscosity at 25°C within this range results in superior coatability for the resin composition for display elements of the present invention. A more preferred lower limit for viscosity of the resin composition for display elements of the present invention is 5 mPa·s, and a more preferred upper limit is 20 mPa·s.

[0079] The resin composition for display elements of the present invention has a preferred upper limit of 3.0 for the dielectric constant of the cured product of the resin composition for display elements, measured under conditions of 25°C and 100kHz. Because the dielectric constant of the cured product is 3.0 or less, the resin composition for display elements of the present invention can be suitably used as a encapsulant for display elements in the manufacture of display elements such as organic EL display elements equipped with touch panels. The preferred upper limit for the dielectric constant of the cured product is 2.8, and the more preferred upper limit is 2.6. Furthermore, there is no particular preferred lower limit for the dielectric constant of the above-mentioned cured product, but the practical lower limit is 2.2. The above-mentioned "dielectric constant" can be measured using a dielectric constant measuring device. For example, to measure the dielectric constant of a cured material, a resin composition for display elements is applied to a PET film to a thickness of 100 μm, and then, in a dry chamber with a dew point of -50°C or lower, light with a wavelength of 395 nm is applied using an LED UV lamp at an illuminance of 1000 mW / cm². 2 3000 mJ / cm 2 It can be obtained by irradiation.

[0080] The resin composition for display elements of the present invention is suitably used in the manufacture of display elements equipped with capacitive touch panels, and is particularly suitably used as a encapsulant for organic EL display elements. [Effects of the Invention]

[0081] According to the present invention, it is possible to provide a resin composition for display elements in which the cured product has excellent low dielectric properties and can suppress odor. [Modes for carrying out the invention]

[0082] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0083] (Examples 1-7, Comparative Examples 1-3) Resin compositions for display elements in Examples 1-7 and Comparative Examples 1-3 were prepared by uniformly stirring and mixing each material using a homodisperser-type stirrer at a stirring speed of 3000 rpm, according to the mixing ratios listed in Table 1. A Homodisperser L-type (manufactured by Primix Corporation) was used as the homodisperser-type stirrer. Note that "X-22-169" in Table 1 refers to R in equation (3) above. 4 is a methyl group, R 5 The compound is a dimethylene group and n is 0, and "SCS-2" is the compound in formula (4) above, R 6 is a methyl group, R 7 is a dimethylene group, R 8 It is a compound in which is a methyl group, l is 0, and m is 1.

[0084] <Rating> The following evaluations were performed on the obtained resin compositions for display elements. The results are shown in Table 1. Furthermore, since the resin composition for the display element obtained in Comparative Example 2 could not be cured under the conditions described later, the dielectric constant of the cured product was not measured.

[0085] (viscosity) The viscosity of the obtained resin composition for display elements was measured using an E-type viscometer with a CP1 type cone plate at 25°C and 10 rpm. A VISCOMETER TV-22 (manufactured by Toki Sangyo Co., Ltd.) was used as the E-type viscometer.

[0086] (curable) The obtained resin composition for the display element was applied to a glass substrate measuring 5 cm in length, 5 cm in width, and 1 mm in thickness using a spin coater under conditions of 500 rpm for 15 seconds to obtain a coating film with a thickness of 10 μm. Next, light with a wavelength of 395 nm was applied using an LED UV lamp at an illuminance of 1000 mW / cm². 2 3000 mJ / cm 2 The resin composition for the display element was cured by irradiation to obtain a test specimen. The surface tackiness of the obtained test specimens was confirmed. Furthermore, the surface tackiness was confirmed again after the obtained test specimens were left to stand in a dry box for 5 minutes. The curability was evaluated according to the following criteria. ○: If surface tackiness is not confirmed in the evaluation after light irradiation. △: Surface tackiness was confirmed in the evaluation after light irradiation, but not in the evaluation after standing in a dry box for 5 minutes. ×: If surface tackiness is confirmed in the evaluation after light irradiation, and also after standing in a dry box for 5 minutes,

[0087] (dielectric constant of the cured product) The obtained resin composition for the display element was coated onto a PET film to a thickness of 100 μm, and then exposed to light with a wavelength of 395 nm at an illuminance of 1000 mW / cm² using an LED UV lamp in a dry chamber with a dew point of -50°C or lower. 2 3000 mJ / cm 2 A cured material was obtained by irradiation. An SQ series LED UV lamp (manufactured by Quark Technology, Inc.) was used. Subsequently, gold electrodes were vacuum-deposited onto both sides of the obtained cured material in a circular shape with a diameter of 2 cm and a thickness of 0.1 μm, so as to face each other, to prepare a test specimen for dielectric constant measurement. The dielectric constant of the obtained test specimen was measured using a dielectric constant measuring device under the conditions of 25°C and 100 kHz. A 1260 impedance analyzer (manufactured by Solartron, Inc.) and a 1296 dielectric constant measurement interface (manufactured by Solartron, Inc.) were used as the dielectric constant measuring device.

[0088] (Odor evaluation) The obtained resin compositions for display elements were evaluated based on odor (monomer odor) at 25°C by five healthy sensory testers who determined whether or not they experienced any unpleasant odor, according to the following criteria. ○: If all 5 people determine that they feel no discomfort. △: If 1 or 2 out of 5 people determine that they feel uncomfortable. ×: If 3 or more out of 5 people determine that they feel uncomfortable.

[0089] [Table 1] [Industrial applicability]

[0090] According to the present invention, it is possible to provide a resin composition for display elements in which the cured product has excellent low dielectric properties and can suppress odor.

Claims

1. A resin composition for display elements containing a curable resin and a photocationic polymerization initiator, The curable resin comprises a curable resin A represented by the following formula (1) and a curable resin B having a boiling point of 260°C or higher. The content of the curable resin A in 100 parts by mass of the curable resin is 30 parts by mass or more and 90 parts by mass or less. A resin composition for display elements characterized by the following features. 【Chemistry 1】 In formula (1), R １ and R ２ Each of these is independently either a hydrogen atom or a methyl group.

2. The resin composition for a display element according to claim 1, wherein the curable resin B has at least one structure selected from the group consisting of a styrene skeleton, an alicyclic or non-alicyclic epoxy group, and an oxetanyl group.

3. Furthermore, the resin composition for a display element according to claim 1 or 2, further containing a viscosity modifier.

4. The resin composition for a display element according to claim 1 or 2, wherein the viscosity measured using an E-type viscometer at 25°C and 10 rpm is 1 mPa·s or more and 30 mPa·s or less.

5. The resin composition for a display element according to claim 1 or 2, wherein the dielectric constant of the cured product measured under conditions of 25°C and 100kHz is 3.0 or less.

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