Sealing agent for display element

Abstract

To provide a sealing agent for a display element which is excellent in inkjet coating property, and low dielectric characteristics after curing.SOLUTION: A sealing agent for a display element contains a curable resin, a cationic photopolymerization initiator, and a styrenic elastomer having a melt mass flow rate of 5.0 g / 10 min or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a sealant for a display element. [Background technology]

[0002] Touch panels are used in electronic devices such as mobile phones, smartphones, car navigation systems, and personal computers. Among them, capacitive touch panels have rapidly become popular due to their excellent functionality. In particular, in recent years, development of display elements such as organic electroluminescence (EL) display elements equipped with capacitive touch panels has progressed. As a sealant for display elements used in display elements equipped with touch panels, a material having appropriate viscosity, excellent application properties, and excellent curing properties is required. For example, Cited Document 1 discloses an ultraviolet-curable resin composition containing an acrylic compound as a main component as such a sealant for display elements. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-95573 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, display elements have been required to be thinner in order to accommodate foldable devices and the like. Accordingly, sealants are required to have low dielectric properties such as low dielectric constant and low dielectric loss tangent in order to prevent a decrease in the response speed of touch panels, etc. Here, in the manufacture of display elements, application by an inkjet method is often used to apply sealants quickly and uniformly, but conventional sealants have a problem in that it is difficult to achieve both inkjet application properties and low dielectric properties after curing.

[0005] An object of the present invention is to provide a sealant for display elements that has excellent ink-jet coatability and low dielectric properties after curing. [Means for solving the problem]

[0006] Disclosure 1 is a sealant for display elements that contains a curable resin, a photocationic polymerization initiator, and a styrene-based elastomer having a melt mass-flow rate of 5.0 g / 10 min or more. Disclosure 2 relates to the sealant for a display element of Disclosure 1, wherein the curable resin includes at least one selected from the group consisting of a styrene skeleton-containing compound and an aliphatic epoxy compound. Disclosure 3 relates to the sealant for display elements of Disclosure 1 or 2, wherein the styrene-based elastomer is at least one selected from the group consisting of styrene-(ethylene / butylene)-styrene 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. Disclosure 4 is the sealant for display elements of Disclosure 1, 2, or 3, wherein the content of the styrene-based elastomer copolymer relative to 100 parts by mass of the curable resin is 1.5 parts by mass or more and 5 parts by mass or less. Disclosure 5 is the sealant for a display element according to Disclosure 1, 2, 3, or 4, further comprising a sensitizer. Disclosure 6 is a sealant for display elements according to Disclosure 1, 2, 3, 4 or 5, which is used for application by an inkjet method. The present invention will be described in detail below.

[0007] The present inventors have investigated the use of a low-dielectric-constant material for a sealant for display elements to improve the low-dielectric properties after curing, while adjusting the viscosity to improve inkjet coating properties. However, simply adjusting the viscosity of the sealant for display elements can result in the sealant being unable to be ejected from an inkjet device or flowing out without maintaining its coating shape. Therefore, the present inventors have conducted further intensive research and have investigated the use of a sealant for display elements containing a curable resin and a cationic photopolymerization initiator, which further contains a styrene-based elastomer having a melt mass-flow rate equal to or greater than a specific value. As a result, they have found that a sealant for display elements having excellent inkjet coating properties and low-dielectric properties after curing can be obtained, thereby completing the present invention.

[0008] The sealant for a display element of the present invention contains a curable resin. The curable resin preferably contains at least one selected from the group consisting of a styrene skeleton-containing compound and an aliphatic epoxy compound. By containing at least one selected from the group consisting of the styrene skeleton-containing compound and the aliphatic epoxy compound, the display element sealant of the present invention becomes more excellent in inkjet coatability and low dielectric properties after curing. In particular, from the viewpoint of further improving the low dielectric properties after curing of the resulting display element sealant, it is more preferable that the curable resin contains a styrene skeleton-containing compound. In this specification, the "styrene skeleton-containing compound" refers to a compound having a structure in which a benzene ring and a linear carbon-carbon double bond are bonded, and the "aliphatic epoxy compound" refers to an epoxy compound that does not have an aromatic ring skeleton.

[0009] Examples of the styrene skeleton-containing compound include divinylbenzene, 1,3-diisopropenylbenzene, 1,3-bis(1-phenylethenyl)benzene, α-methylstyrene dimer, 4-vinylbiphenyl, and 1,2-bis(vinylphenyl)ethane.

[0010] Examples of the aliphatic epoxy compound include compounds represented by the following formula (1), compounds represented by the following formula (2), ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, 3,4-epoxycyclohexylmethyl(3,4-epoxy)cyclohexanecarboxylate, 4,4'-bis(1,2-epoxycyclohexane), etc. Among these, the compounds represented by the following formula (1) and the compounds represented by the following formula (2) are preferred because they make it easier to lower the dielectric constant of the resulting cured product of the sealant for display elements and provide it with superior heat resistance.

[0011] [ka]

[0012] In formula (1), R 1 are each independently an alkyl group having 1 to 10 carbon atoms, and R 2 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 (2), R 3 are each independently an alkyl group having 1 to 10 carbon atoms, and R 4 is a bond or an alkylene group having 1 to 6 carbon atoms, and R 5 are each independently an alkyl group having 1 to 10 carbon atoms, a group represented by the following formula (3-1), a group represented by the following formula (3-2), a group represented by the following formula (3-3), or a group represented by the following formula (3-4). In formula (2), l represents an integer of 0 to 1000, and m represents an integer of 1 to 100. However, R 5is not a group represented by the following formula (3-1), m represents an integer of 2 or more and 100 or less.

[0015] [ka]

[0016] In formulas (3-1) to (3-4), R 6 represents a bond or an alkylene group having 1 to 6 carbon atoms, and in formula (3-3), R 7 represents hydrogen or an alkyl group having 1 to 6 carbon atoms, and R 8 represents a bond or a methylene group, and in formula (3-4), R 9 represents hydrogen or a methyl group.

[0017] The curable resin may contain other curable resins in addition to the styrene skeleton-containing compound and the aliphatic epoxy compound. Examples of the other curable resins include epoxy compounds, oxetane compounds, and (meth)acrylic compounds having an aromatic ring skeleton. In this specification, the term "(meth)acrylic" means acrylic or methacrylic.

[0018] The preferred lower limit of the total content of the curable resins in 100 parts by mass of the sealant for display elements of the present invention is 80 parts by mass, and the preferred upper limit is 98 parts by mass. When the total content of the curable resins is within this range, the resulting sealant for display elements will have better curability and adhesiveness.

[0019] The sealant for a display element of the present invention contains a photocationic polymerization initiator. 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 either an ionic photoacid generating type or a nonionic photoacid generating type.

[0020] The anion moiety 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 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, each of which has the anion moiety.

[0021] 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, 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.

[0022] 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.

[0023] Examples of the aromatic diazonium salt include phenyldiazonium hexafluorophosphate, phenyldiazonium hexafluoroantimonate, phenyldiazonium tetrafluoroborate, and phenyldiazonium tetrakis(pentafluorophenyl)borate.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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 Chemical Industries, Ltd., and cationic photopolymerization initiators manufactured by San-Apro Corporation. Examples of the cationic photopolymerization initiators manufactured by Midori Chemical Co., Ltd. include DTS-200. Examples of the cationic photopolymerization initiators manufactured by Union Carbide 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 initiator manufactured by 3M include FC-508 and FC-512. Examples of the cationic photopolymerization initiators manufactured by BASF include IRGACURE261 and IRGACURE290. Examples of the cationic photopolymerization initiators manufactured by Solvay include PI2074. Examples of the cationic photopolymerization initiators manufactured by San-Apro include CPI-100P, CPI-200K, and CPI-210S.

[0028] The preferred lower limit of the content of the cationic photopolymerization initiator relative to 100 parts by mass of the curable resin is 0.01 parts by mass, and the preferred upper limit is 10 parts by mass. When the content of the cationic photopolymerization initiator is 0.01 parts by mass or more, the resulting sealant for display elements has superior curability. When the content of the cationic photopolymerization initiator is 10 parts by mass or less, the curing reaction of the resulting sealant for display elements does not become too fast, resulting in superior workability and a more uniform cured product. The more preferred lower limit of the content of the cationic photopolymerization initiator is 0.05 parts by mass, and the more preferred upper limit is 5 parts by mass.

[0029] The sealant for display elements of the present invention contains a styrene-based elastomer (hereinafter also referred to as the "styrene-based copolymer of the present invention") having a melt mass-flow rate (hereinafter also referred to as "MFR") of 5.0 g / 10 min or more. By containing the styrene-based copolymer of the present invention, the sealant for display elements of the present invention has excellent inkjet coatability and low dielectric properties after curing.

[0030] The lower limit of the MFR of the styrene copolymer according to the present invention is 5.0 g / 10 min. When the styrene copolymer according to the present invention has an MFR of 5.0 g / 10 min or more, the sealant for display elements according to the present invention has excellent inkjet coatability. Furthermore, although there is no particular upper limit to the MFR of the styrene copolymer according to the present invention, the substantial upper limit is 30 g / 10 min. The MFR is an index showing the fluidity when melted, and means a value measured in accordance with JIS K 7210-1.

[0031] From the viewpoint of making the resulting sealant for display elements have better inkjet coatability, the styrene-based copolymer according to the present invention is preferably at least one selected from the group consisting of styrene-(ethylene / butylene)-styrene 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, and more preferably a styrene-(ethylene / butylene)-styrene copolymer.

[0032] The preferred lower limit of the weight-average molecular weight of the styrene copolymer according to the present invention is 20,000, and the preferred upper limit is 400,000. When the weight-average molecular weight of the styrene copolymer according to the present invention is within this range, the resulting sealant for display elements has better inkjet coatability. In this specification, the weight-average molecular weight is a value determined by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent and converted into polystyrene. Examples of columns used for measuring the weight-average molecular weight converted into polystyrene by GPC include Shodex LF-804 (manufactured by Showa Denko K.K.).

[0033] The preferred lower limit of the content of the styrene copolymer according to the present invention relative to 100 parts by mass of the curable resin is 1.5 parts by mass, and the preferred upper limit is 5 parts by mass. When the content of the styrene copolymer according to the present invention is within this range, the resulting sealant for display elements has better inkjet coatability. The more preferred lower limit of the content of the styrene copolymer according to the present invention is 2.5 parts by mass.

[0034] The sealant for display elements of the present invention preferably further contains a sensitizer, which serves to further improve the polymerization initiation efficiency of the cationic photopolymerization initiator and further accelerate the curing reaction of the sealant for display elements of the present invention.

[0035] 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. Examples of the anthracene compound include 9,10-dibutoxyanthracene. Examples of the thioxanthone compound include 2,4-diethylthioxanthone. These sensitizers may be used alone or in combination of two or more.

[0036] The preferred lower limit of the content of the sensitizer relative to 100 parts by mass of the curable resin is 0.01 parts by mass, and the preferred upper limit is 3 parts by mass. When the content of the sensitizer is 0.01 parts by mass or more, the sensitizing effect is more pronounced. When the content of the sensitizer is 3 parts by mass or less, light can be transmitted to deep areas 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.

[0037] The sealant for display elements of the present invention preferably further contains a surface conditioner. By containing the surface conditioner, the surface tension of the sealant for display elements of the present invention can be adjusted, thereby imparting flatness to the coating film. Examples of the surface conditioner include surfactants and leveling agents.

[0038] 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. Examples of the surface conditioner manufactured by Shin-Etsu Chemical Co., Ltd. include X-22-163A. Examples of the surface conditioner manufactured by BYK Japan include BYK-330, BYK-340, and BYK-345. An example of the surface conditioner manufactured by AGC Seimi Chemical Co., Ltd. is Surflon S-611.

[0039] The preferred lower limit of the content of the surface conditioner relative to 100 parts by mass of the curable resin is 0.1 parts by mass, and the preferred upper limit is 1 part by mass. When the content of the surface conditioner is within this range, the surface tension of the resulting sealant for display elements can be more easily adjusted.

[0040] The sealant for a display element of the present invention may further contain a stabilizer. By containing the stabilizer, the sealant for a display element obtained has better storage stability.

[0041] 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.

[0042] The preferred lower limit of the amount of the stabilizer relative to 100 parts by mass of the curable resin is 0.005 parts by mass, and the preferred upper limit is 0.05 parts by mass. When the amount of the stabilizer is within this range, the resulting sealant for display elements has excellent storage stability while maintaining excellent curability.

[0043] The sealant for a display element of the present invention may further contain a silane coupling agent, which serves to improve the adhesion between the sealant for a display element of the present invention and a substrate or the like.

[0044] 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.

[0045] The preferred lower limit of the content of the silane coupling agent relative to 100 parts by mass of the curable resin is 0.1 parts by mass, and the preferred upper limit is 10 parts by mass. By using the silane coupling agent in this range, the adhesiveness of the resulting sealant for display elements can be improved while suppressing bleed-out due to excess silane coupling agent. The more preferred lower limit of the content of the silane coupling agent is 0.5 parts by mass, and the more preferred upper limit is 5 parts by mass.

[0046] The sealant for a display element of the present invention may further contain a curing retarder. By containing the curing retarder, the pot life of the resulting sealant for a display element can be extended.

[0047] Examples of the curing retarder include polyether compounds. Examples of the polyether compound include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, crown ether compounds, etc. Among these, crown ether compounds are preferred.

[0048] The preferred lower limit of the content of the curing retarder relative to 100 parts by mass of the curable resin is 0.05 parts by mass, and the preferred upper limit is 5.0 parts by mass. By having the content of the curing retarder within this range, the retardation effect can be enhanced while suppressing the generation of outgassing when the resulting sealant for display elements is cured. 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.

[0049] The sealant for a display element of the present invention may further contain a compound that reacts with the acid generated in the composition or an ion exchange resin, within the range that does not impair the object of the present invention.

[0050] 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.

[0051] 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.

[0052] Furthermore, the sealant for a display element of the present invention may contain various known additives such as a reinforcing agent, a softener, a plasticizer, a viscosity modifier, and an ultraviolet absorber, if necessary.

[0053] Examples of a method for producing the sealant for display elements of the present invention include a method of mixing a curable resin, a polymerization initiator, and additives such as a sensitizer, which are 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.

[0054] The sealant for a display element of the present invention is suitably used for application by an inkjet method. The sealant for display elements of the present invention has a viscosity, measured using an E-type viscometer at 25°C and 10 rpm, of preferably 2.9 mPa s at the lower limit and 30 mPa s at the upper limit. When the viscosity is within this range, the sealant for display elements of the present invention has superior inkjet coatability. The sealant for display elements of the present invention has a more preferred viscosity lower limit of 5 mPa s and a more preferred upper limit of 20 mPa s.

[0055] The display element sealant of the present invention has a dielectric constant of a cured product of the display element sealant measured at 25°C and 1 GHz of preferably 2.8. Since the dielectric constant of the cured product is 2.8 or less, the display element sealant of the present invention can be suitably used in thin display devices having touch panels, etc. The upper limit of the dielectric constant of the cured product is more preferably 2.6, and even more preferably 2.4. There is no particular preferred lower limit for the dielectric constant of the cured product, but the substantial lower limit is 2.0. The "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 sealant for display elements to a PET film to a thickness of 100 μm, and then irradiating the cured product with ultraviolet light of 395 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 at 3000mJ / cm 2 It can be obtained by irradiation.

[0056] The sealant for display elements of the present invention is particularly suitable for use as a sealant for organic EL display elements. [Effects of the Invention]

[0057] According to the present invention, it is possible to provide a sealant for display elements that has excellent inkjet coating properties and low dielectric properties after curing. DETAILED DESCRIPTION OF THE INVENTION

[0058] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0059] (Examples 1 to 7, Comparative Examples 1 to 4) The materials were uniformly stirred and mixed at a stirring speed of 3000 rpm using a homodisper-type stirring mixer according to the blending ratios shown in Tables 1 and 2 to prepare sealants for display elements of Examples 1 to 7 and Comparative Examples 1 to 4. As the homodisper-type stirring mixer, a homodisper L model (manufactured by Primix Corporation) was used. In addition, "SEBS copolymer" in Tables 1 and 2 means a styrene-(ethylene / butylene)-styrene copolymer.

[0060] <Evaluation> The sealants for display elements obtained in the examples and comparative examples were evaluated as follows, and the results are shown in Tables 1 and 2.

[0061] (viscosity) The viscosity of the obtained sealant for a display element was measured using an E-type viscometer with a CP1 type cone plate at 25° C. and 10 rpm. The E-type viscometer used was a VISCOMETER TV-22 (manufactured by Toki Sangyo Co., Ltd.).

[0062] (Inkjet coating properties) The obtained sealant for display elements was applied onto a silicon wafer in droplets of 10 pL at a speed of 6 m / sec, 1 kHz, and 1 mm pitch using an inkjet discharge device (manufactured by FUJIFILM DIMATIX, "DMP-2800"). The inkjet coatability was evaluated by rating "◯" if the ink was able to be ejected and the coating shape was maintained, and rating "×" if the ink was unable to be ejected or the coating shape could not be maintained and the ink flowed out.

[0063] (Low dielectric properties after curing) The obtained sealant for display elements was applied to a PET film to a thickness of 100 μm, and then exposed to ultraviolet light with 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 2A cured film was obtained by irradiating the sample with UV light. An SQ Series LED UV lamp (manufactured by Quark Technology) was used. Then, gold electrodes were vacuum-deposited on both sides of the cured film, facing each other, to form circular electrodes with a diameter of 2 cm and a thickness of 0.1 μm, 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. A 1260-type impedance analyzer (manufactured by Solartron) and a 1296-type dielectric constant measurement interface (manufactured by Solartron) were used as the dielectric constant measurement device.

[0064] [Table 1]

[0065] [Table 2] [Industrial Applicability]

[0066] According to the present invention, it is possible to provide a sealant for display elements that has excellent inkjet coating properties and low dielectric properties after curing.

Claims

1. The composition contains a curable resin, a photocationic polymerization initiator, and a styrene-based elastomer having a melt mass-flow rate of 5.0 g / 10 min or more. A sealant for a display element, characterized in that:

2. 2. The sealant for display elements according to claim 1, wherein the curable resin contains at least one selected from the group consisting of a styrene skeleton-containing compound and an aliphatic epoxy compound.

3. 3. The sealant for display elements according to claim 1 or 2, wherein the styrene-based elastomer is at least one selected from the group consisting of styrene-(ethylene / butylene)-styrene 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.

4. 3. The sealant for display elements according to claim 1, wherein the content of the styrene-based elastomer is 1.5 parts by mass or more and 5 parts by mass or less relative to 100 parts by mass of the curable resin.

5. 3. The sealant for a display element according to claim 1, further comprising a sensitizer.

6. 3. The sealant for display elements according to claim 1, which is applied by an ink jet method.

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