Sealing agent for liquid crystal display element and liquid crystal display element

Abstract

The present application aims to provide a sealant for liquid crystal display elements, which is excellent in visible light curability and low in liquid crystal contamination. In addition, the present application aims to provide a liquid crystal display element using the sealant for liquid crystal display elements. The present application is a sealant for liquid crystal display elements, which contains a curable resin, a photopolymerization initiator and a sensitizer, the photopolymerization initiator containing camphorquinone, when the absorbance at a wavelength of 400 nm is 0.1 or more, in a case where the absorbance of a range of 300 nm or more and 550 nm or less in a wavelength at the time when the maximum value is set to 1 by measuring an absorption spectrum of a solution in which the sensitizer is dissolved in acetonitrile so that the concentration is 20 mg / L.

Description

TECHNICAL FIELD

[0001] The present application relates to a sealant for liquid crystal display elements, which is excellent in visible light curing and in low liquid crystal contamination. In addition, the present application relates to a liquid crystal display element using the sealant for liquid crystal display elements. BACKGROUND

[0002] In recent years, as a manufacturing method of liquid crystal display elements such as liquid crystal display units, from the viewpoint of shortening of production cycle time, optimization of the amount of liquid crystal used, and the like, a liquid crystal dropping method called a dropping process using a sealant of a light and heat combined curing type disclosed in Patent Literature 1, Patent Literature 2 is used.

[0003] In the dropping process, first, a frame-shaped seal pattern is formed on one of two transparent substrates with electrodes by a dispensing method. Next, a fine drop of liquid crystal is dropped onto the entire surface of the frame of the transparent substrate in a state where the sealant is not cured, the other transparent substrate is immediately laminated, and light such as ultraviolet light is irradiated to the seal portion to perform pre-curing. Then, the formal curing is performed by heating at the time of liquid crystal annealing, and a liquid crystal display element is produced. If the lamination of the substrates is performed under reduced pressure, the liquid crystal display element can be manufactured with extremely high efficiency, and currently the dropping process has become mainstream as a manufacturing method of liquid crystal display elements.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Application Laid-Open No. 2001-133794

[0007] Patent Literature 2: International Publication No. 02 / 092718 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] In the modern age where various mobile devices with liquid crystal panels such as mobile phones, portable game machines, and the like are spreading, miniaturization of the devices is the most required problem. As a method of miniaturization of the devices, the narrow frame of the liquid crystal display portion can be cited, and for example, a technique related to the configuration of the position of the seal portion under the black matrix (hereinafter, also referred to as a narrow frame design) is performed.

[0010] However, in the narrow frame design, since the sealant is disposed directly under the black matrix, if the dropping process is performed, there is a problem that the light irradiated at the time of light curing of the sealant is blocked, the light cannot reach the inside of the sealant, and the curing becomes insufficient. If the curing of the sealant becomes insufficient like this, the problem of the outflow of the uncured sealant component into the liquid crystal to cause liquid crystal contamination occurs.

[0011] In addition, generally, irradiation of ultraviolet rays is performed as a method of photocuring the sealant, but particularly in a liquid crystal dropping process, since the sealant is cured after the liquid crystal is dropped, there is a problem that the liquid crystal deteriorates due to the irradiation of ultraviolet rays. Therefore, in order to prevent the deterioration of the liquid crystal due to the ultraviolet rays, an operation of incorporating a photopolymerization initiator excellent in reactivity to long-wavelength light such as an oxime ester-based photopolymerization initiator, and curing the sealant by light irradiation through a cut filter or the like is performed. However, in the case of using the photopolymerization initiator such as the oxime ester-based photopolymerization initiator, there is a problem that liquid crystal contamination is easily generated.

[0012] An object of the present application is to provide a sealant for a liquid crystal display element which is excellent in visible light curability and in low liquid crystal contamination. In addition, an object of the present application is to provide a liquid crystal display element using the sealant for a liquid crystal display element.

[0013] Means for solving the problem

[0014] Disclosed is a sealant for a liquid crystal display element, which contains a curable resin, a photopolymerization initiator, and a sensitizer, the photopolymerization initiator containing camphorquinone, when the absorbance at a wavelength of 400 nm is 0.1 or more, in a case where the absorbance in a range of 300 nm or more and 550 nm or less of a wavelength is taken as 1, when an absorbance spectrum is measured for a solution in which the sensitizer is dissolved in acetonitrile so that the concentration is 20 mg / L.

[0015] Disclosed is a sealant for a liquid crystal display element according to the present disclosure 1, in which the sensitizer has at least one structure selected from a coumarin skeleton, an acridine skeleton, and a thioxanthone skeleton.

[0016] Disclosed is a sealant for a liquid crystal display element according to the present disclosure 2, in which the sensitizer is at least one selected from 3-benzoyl-7-diethylaminocoumarin, 3,3-carbonylbis(7-diethylaminocoumarin), acridine-3,6-diamine, and 2,4-diethylthioxanth-9-one, and 9,10-phenanthrenequinone.

[0017] Disclosed is a sealant for a liquid crystal display element according to the present disclosure 1, 2, or 3, in which the content ratio of the sensitizer is 0.1 parts by weight or more and 200 parts by weight or less, with respect to 100 parts by weight of the camphorquinone.

[0018] Disclosed is a liquid crystal display element having a cured product of the sealant for a liquid crystal display element according to the present disclosure 1, 2, 3, or 4.

[0019] Hereinafter, the present application will be described in detail.

[0020] The present inventors have considered that the cause of liquid crystal contamination in the case of using an oxime ester-based photopolymerization initiator or the like as a photopolymerization initiator is that these photopolymerization initiators are cleavage-type photopolymerization initiators, and thus residues are generated after light irradiation. Therefore, the present inventors have conducted intensive studies, and as a result, have found that by combining camphorquinone, which is a hydrogen abstraction-type photopolymerization initiator, with a specific sensitizer, a sealing agent for liquid crystal display elements, which is excellent in visible light curability and excellent in low liquid crystal contamination, can be obtained, and thus the present invention has been completed.

[0021] The sealing agent for liquid crystal display elements of the present invention contains a photopolymerization initiator.

[0022] The above-mentioned photopolymerization initiator contains the above-mentioned camphorquinone. By combining the above-mentioned camphorquinone, which is the above-mentioned photopolymerization initiator, with the below-mentioned sensitizer, the sealing agent for liquid crystal display elements of the present invention is excellent in visible light curability and excellent in low liquid crystal contamination.

[0023] The content of the above-mentioned camphorquinone is preferably 0.3 parts by weight or more and 3.0 parts by weight or less, relative to 100 parts by weight of the curable resin. By making the content of the above-mentioned camphorquinone 0.3 parts by weight or more, the sealing agent for liquid crystal display elements obtained is more excellent in visible light curability. By making the content of the above-mentioned camphorquinone 3.0 parts by weight or less, the sealing agent for liquid crystal display elements obtained is more excellent in low liquid crystal contamination. The content of the above-mentioned camphorquinone is more preferably 0.7 parts by weight or more and 2.3 parts by weight or less, further preferably 1.1 parts by weight or more and 1.8 parts by weight or less.

[0024] The sealing agent for liquid crystal display elements of the present invention contains a sensitizer.

[0025] As for the above-mentioned sensitizer, when the absorbance at a wavelength of 400 nm is 0.1 or more in the case where the absorbance at a wavelength of 300 nm or more and 550 nm or less is taken as 1 in the case where the absorbance spectrum of a solution in which the sensitizer is dissolved in acetonitrile so as to have a concentration of 20 mg / L is measured, the sensitizer is also referred to as "the sensitizer of the present invention". By combining the sensitizer of the present invention with the above-mentioned camphorquinone, the sealing agent for liquid crystal display elements of the present invention is excellent in visible light curability and excellent in low liquid crystal contamination.

[0026] Regarding the sensitizer of the present invention, when measuring the absorbance spectrum of a solution prepared by dissolving the sensitizer in acetonitrile to a concentration of 20 mg / L, and setting the maximum absorbance value in the wavelength range of 300 nm to 550 nm as 1, the absorbance at a wavelength of 400 nm is 0.1 or higher. By ensuring that the absorbance of the sensitizer of the present invention at a wavelength of 400 nm is 0.1 or higher, the visible light curability of the sealant for liquid crystal display elements of the present invention is excellent. As a result, the effect of suppressing liquid crystal contamination caused by the residue of uncured curable resin also becomes excellent. The absorbance of the sensitizer of the present invention at a wavelength of 400 nm is preferably 0.3 or higher, more preferably 0.5 or higher.

[0027] The absorbance described above can be measured using a spectrophotometer with an optical path length of 1 cm. Examples of such spectrophotometers include the U-3900 (manufactured by Hitachi High-Tech Science).

[0028] Regarding the sensitizer of the present invention, when measuring the absorbance spectrum of a solution prepared by dissolving the sensitizer in acetonitrile to a concentration of 20 mg / L, and setting the maximum absorbance value in the wavelength range of 300 nm to 550 nm as 1, the absorbance at a wavelength of 450 nm is preferably 0.07 or higher. By ensuring that the absorbance of the sensitizer of the present invention at a wavelength of 450 nm is 0.07 or higher, the visible light curability of the sealant for liquid crystal display elements of the present invention becomes more excellent, and as a result, the effect of suppressing liquid crystal contamination caused by the residue of uncured curable resin also becomes more excellent. The absorbance of the sensitizer of the present invention at a wavelength of 450 nm is more preferably 0.2 or higher, and even more preferably 0.3 or higher.

[0029] Examples of sensitizers used in this invention include 3-benzoyl-7-diethylaminocoumarin, 3,3-carbonylbis(7-diethylaminocoumarin), acridine-3,6-diamine, 2,4-diethylthioxanthion-9-one, and 9,10-phenanthraquinone. The sensitizers of this invention can be used alone or in combination of two or more.

[0030] The sensitizer of the present invention preferably has at least one structure selected from the coumarin skeleton, the acridine skeleton and the thioxanthone skeleton, more preferably at least one structure selected from 3-benzoyl-7-diethylaminocoumarin, 3,3-carbonylbis(7-diethylaminocoumarin), acridine-3,6-diamine and 2,4-diethylthioxanthone-9-one, 9,10-phenanthroquinone.

[0031] The preferable lower limit of the content ratio of the sensitizer of the present application relative to 100 parts by weight of the above camphorquinone is 0.1 parts by weight, and the preferable upper limit is 200 parts by weight. By setting the content ratio of the sensitizer of the present application within this range, the visible light curability and the low liquid crystal contamination of the sealant for liquid crystal display elements obtained thereby become more excellent. The more preferable lower limit of the content ratio of the sensitizer of the present application is 1 parts by weight, and the more preferable upper limit is 50 parts by weight, and the further preferable upper limit is 10 parts by weight.

[0032] The sealant for liquid crystal display elements of the present application contains a curable resin.

[0033] The above curable resin preferably contains a (meth)acrylic compound.

[0034] As the above (meth)acrylic compound, for example, a (meth)acrylate compound, an epoxy (meth)acrylate, a urethane (meth)acrylate, etc. can be given. Among them, an epoxy (meth)acrylate is preferable. In addition, from the viewpoint of reactivity, the above (meth)acrylic compound preferably has two or more (meth)acryloyl groups in one molecule.

[0035] Note that, in the present specification, the above "(meth)acrylic acid" means acrylic acid or methacrylic acid, the above "(meth)acrylic compound" means a compound having a (meth)acryloyl group, and the above "(meth)acryloyl group" means an acryloyl group or a methacryloyl group. In addition, the above "(meth)acrylate" means an acrylate or a methacrylate. Furthermore, the above "epoxy (meth)acrylate" means a compound obtained by reacting all of the epoxy groups in an epoxy compound with a (meth)acrylic acid.

[0036] As the monofunctional compound in the above (meth)acrylate compound, for example, mention can be made of methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, isomyristyl (meth)acrylate, stearyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, benzyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, methoxyethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxy polyethylene glycol (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, ethyl carbitol (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, 1H, 1H, 5H-octafluoropentyl (meth)acrylate, imide (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, succinic acid-2-(meth)acryloyloxyethyl ester, hexahydrophthalic acid-2-(meth)acryloyloxyethyl ester, 2-(meth)acryloyloxyethyl 2-hydroxypropyl phthalate, 2-(meth)acryloyloxyethyl phosphate, glycidyl (meth)acrylate, and the like.

[0037] In addition, as the 2-functional compound among the above (meth)acrylate compounds, for example, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 2-n-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, oxirane-addition bisphenol A di(meth)acrylate, oxirane-addition bisphenol A di(meth)acrylate, oxirane-addition bisphenol F di(meth)acrylate, dihydroxymethyl dicyclopentadienyl di(meth)acrylate, oxirane-modified isocyanuric acid di(meth)acrylate, 2-hydroxy-3-(meth)acryloyloxypropyl (meth)acrylate, carbonate glycol di(meth)acrylate, polyether glycol di(meth)acrylate, polyester glycol di(meth)acrylate, polycaprolactone glycol di(meth)acrylate, polybutadiene glycol di(meth)acrylate, and the like can be given.

[0038] In addition, as the 3 or more functional compound among the above (meth)acrylate compounds, for example, trimethylolpropane tri(meth)acrylate, oxirane-addition trimethylolpropane tri(meth)acrylate, oxirane-addition trimethylolpropane tri(meth)acrylate, caprolactone-modified trimethylolpropane tri(meth)acrylate, oxirane-addition isocyanuric acid tri(meth)acrylate, glycerol tri(meth)acrylate, oxirane-addition glycerol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, tris(meth)acryloyloxyethyl phosphate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and the like can be given.

[0039] As the above epoxy (meth)acrylate, for example, epoxy (meth)acrylate obtained by reacting an epoxy compound with (meth)acrylic acid in the presence of an alkaline catalyst according to a conventional method, and the like can be given.

[0040] As the epoxy compound to be used as a raw material for synthesizing the above-mentioned epoxy (meth) acrylate, for example, bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol S type epoxy compounds, 2, 2'-diallyl bisphenol A type epoxy compounds, hydrogenated bisphenol type epoxy compounds, propylene oxide addition bisphenol A type epoxy compounds, resorcinol type epoxy compounds, biphenyl type epoxy compounds, thioether type epoxy compounds, diphenyl ether type epoxy compounds, dicyclopentadiene type epoxy compounds, naphthalene type epoxy compounds, phenol novolak type epoxy compounds, o-cresol novolak type epoxy compounds, dicyclopentadiene novolak type epoxy compounds, biphenyl novolak type epoxy compounds, naphthalene phenol novolak type (Japanese: naphthalene phenol novolak type) epoxy compounds, glycidyl amine type epoxy compounds, alkyl polyhydric alcohol type epoxy compounds, rubber-modified type epoxy compounds, glycidyl ester compounds, and the like can be given.

[0041] As the commercially available product of the above-mentioned bisphenol A type epoxy compounds, for example, jER828EL, jER1004 (both manufactured by Mitsubishi Chemical Corporation), EPICLON EXA-850CRP (manufactured by DIC Corporation), and the like can be given.

[0042] As the commercially available product of the above-mentioned bisphenol F type epoxy compounds, for example, jER806, jER4004 (both manufactured by Mitsubishi Chemical Corporation), and the like can be given.

[0043] As the commercially available product of the above-mentioned bisphenol S type epoxy compounds, for example, EPICLON EXA1514 (manufactured by DIC Corporation), and the like can be given.

[0044] As the commercially available product of the above-mentioned 2, 2'-diallyl bisphenol A type epoxy compounds, for example, RE-810NM (manufactured by Nichigo Chemicals, Inc.), and the like can be given.

[0045] As the commercially available product of the above-mentioned hydrogenated bisphenol type epoxy compounds, for example, EPICLON EXA7015 (manufactured by DIC Corporation), and the like can be given.

[0046] As the commercially available product of the above-mentioned propylene oxide addition bisphenol A type epoxy compounds, for example, EP-4000S (manufactured by ADEKA Corporation), and the like can be given.

[0047] As the commercially available product of the above-mentioned resorcinol type epoxy compounds, for example, EX-201 (manufactured by Nagase ChemteX Corporation), and the like can be given.

[0048] As the commercially available product of the above-mentioned biphenyl type epoxy compounds, for example, jER YX-4000H (manufactured by Mitsubishi Chemical Corporation), and the like can be given.

[0049] As a commercially available product of the above-mentioned thioether type epoxy compound, for example, YSLV-50TE (manufactured by NIPPON STEEL Chemical & Material Co., Ltd.) or the like can be given.

[0050] As a commercially available product of the above-mentioned diphenyl ether type epoxy compound, for example, YSLV-80DE (manufactured by NIPPON STEEL Chemical & Material Co., Ltd.) or the like can be given.

[0051] As a commercially available product of the above-mentioned dicyclopentadiene type epoxy compound, for example, EP-4088S (manufactured by ADEKA Corporation) or the like can be given.

[0052] As a commercially available product of the above-mentioned naphthalene type epoxy compound, for example, EPICLON HP4032, EPICLON EXA-4700 (both manufactured by DIC Corporation) or the like can be given.

[0053] As a commercially available product of the above-mentioned phenyl phenol novolak type epoxy compound, for example, EPICLON N-770 (manufactured by DIC Corporation) or the like can be given.

[0054] As a commercially available product of the above-mentioned o-cresol novolak type epoxy compound, for example, EPICLON N-670-EXP-S (manufactured by DIC Corporation) or the like can be given.

[0055] As a commercially available product of the above-mentioned dicyclopentadiene novolak type epoxy compound, for example, EPICLON HP7200 (manufactured by DIC Corporation) or the like can be given.

[0056] As a commercially available product of the above-mentioned diphenol novolak type epoxy compound, for example, NC-3000P (manufactured by Nippon Kayaku Co., Ltd.) or the like can be given.

[0057] As a commercially available product of the above-mentioned naphthol novolak type epoxy compound, for example, ESN-165S (manufactured by NIPPON STEEL Chemical & Material Co., Ltd.) or the like can be given.

[0058] As a commercially available product of the above-mentioned glycidyl amine type epoxy compound, for example, jER630 (manufactured by Mitsubishi Chemical Corporation), EPICLON 430 (manufactured by DIC Corporation), TETRAD-X (manufactured by Mitsubishi Gas Chemical Company, Inc.) or the like can be given.

[0059] As the commercially available product of the above-mentioned alkyl polyol type epoxy compound, for example, ZX-1542 (manufactured by NIPPON STEEL Chemical & Material Co., Ltd.), EPICLON 726 (manufactured by DIC Corporation), EPOLIGHT 80MFA (manufactured by Kyoeisha Chemical Co., Ltd.), Denacol EX-611 (manufactured by Nagase Chemtex Corporation), and the like can be given.

[0060] As the commercially available product of the above-mentioned rubber-modified type epoxy compound, for example, YR-450, YR-207 (both manufactured by NIPPON STEEL Chemical & Material Co., Ltd.), Epolead PB (manufactured by Daicel Corporation), and the like can be given.

[0061] As the commercially available product of the above-mentioned glycidyl ester compound, for example, Denacol EX-147 (manufactured by Nagase Chemtex Corporation), and the like can be given.

[0062] As other commercially available products of the above-mentioned epoxy compound, for example, YDC-1312, YSLV-80XY, YSLV-90CR (all manufactured by NIPPON STEEL Chemical & Material Co., Ltd.), XAC4151 (manufactured by Asahi Kasei Corporation), jER1031, jER1032 (both manufactured by Mitsubishi Chemical Corporation), EXA-7120 (manufactured by DIC Corporation), TEPIC (manufactured by Nissan Chemical Corporation), and the like can be given.

[0063] As the commercially available product of the above-mentioned epoxy (meth)acrylate, for example, epoxy (meth)acrylates manufactured by DAICEL-ALLNEX Corporation, epoxy (meth)acrylates manufactured by Shin-Nakamura Chemical Co., Ltd., epoxy (meth)acrylates manufactured by Kyoeisha Chemical Co., Ltd., epoxy (meth)acrylates manufactured by Nagase Chemtex Corporation, and the like can be given.

[0064] As the epoxy (meth)acrylates manufactured by DAICEL-ALLNEX Corporation, for example, EBECRYL 860, EBECRYL 3200, EBECRYL 3201, EBECRYL 3412, EBECRYL 3600, EBECRYL 3700, EBECRYL 3701, EBECRYL 3702, EBECRYL 3703, EBECRYL 3708, EBECRYL 3800, EBECRYL 6040, EBECRYL RDX63182, and the like can be given.

[0065] As the epoxy (meth) acrylate of the above-mentioned Shin-Nakamura Chemical Co., Ltd., for example, EA-1010, EA-1020, EA-5323, EA-5520, EA-CHD, EMA-1020, etc. can be given.

[0066] As the epoxy (meth) acrylate of the above-mentioned Kyoeisha Chemical Co., Ltd., for example, Epoxy Ester M-600A, Epoxy Ester 40EM, Epoxy Ester 70PA, Epoxy Ester 200PA, Epoxy Ester 80MFA, Epoxy Ester 3002M, Epoxy Ester 3002A, Epoxy Ester 1600A, Epoxy Ester 3000M, Epoxy Ester 3000A, Epoxy Ester 200EA, Epoxy Ester 400EA, etc. can be given.

[0067] As the epoxy (meth) acrylate of the above-mentioned Nagase Chemtex Co., Ltd., for example, Denacol Acrylate DA-141, Denacol Acrylate DA-314, Denacol Acrylate DA-911, etc. can be given.

[0068] The above-mentioned urethane (meth) acrylate can be obtained, for example, by reacting a (meth) acrylate derivative having a hydroxyl group with a polyfunctional isocyanate compound in the presence of a catalytic amount of a tin compound.

[0069] As the above-mentioned polyfunctional isocyanate compound, for example, isophorone diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, diphenylmethane-4,4'-diisocyanate (MDI), hydrogenated MDI, polymeric MDI, 1,5-naphthalene diisocyanate, norbornane diisocyanate, dimethyl diphenyl diisocyanate, xylylene diisocyanate (XDI), hydrogenated XDI, lysine diisocyanate, triphenylmethane triisocyanate, tris(isocyanate phenyl) thiophosphate, tetramethyl xylylene diisocyanate, 1,6,11-undecane triisocyanate, etc. can be given.

[0070] In addition, as the above-mentioned polyfunctional isocyanate compound, a chain-extended polyfunctional isocyanate compound obtained by the reaction of a polyhydric alcohol with an excess of a polyfunctional isocyanate compound can also be used.

[0071] As the above polyhydric alcohol, for example, ethylene glycol, propylene glycol, glycerol, sorbitol, trimethylolpropane, carbonate diol, polyether diol, polyester diol, polycaprolactone diol, and the like can be given.

[0072] As the above (meth)acrylic acid derivative having a hydroxyl group, for example, a hydroxyalkyl (meth)acrylate, a dihydric alcohol mono(meth)acrylate, a trihydric alcohol mono(meth)acrylate or di(meth)acrylate, an epoxy (meth)acrylate, and the like can be given.

[0073] As the above hydroxyalkyl (meth)acrylate, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and the like can be given.

[0074] As the above dihydric alcohol, for example, ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, polyethylene glycol, and the like can be given.

[0075] As the above trihydric alcohol, for example, trimethylol ethane, trimethylol propane, glycerol, and the like can be given.

[0076] As the above epoxy (meth)acrylate, for example, a bisphenol A type epoxy acrylate and the like can be given.

[0077] As the above urethane (meth)acrylate, for example, a urethane (meth)acrylate manufactured by Toagosei Co., Ltd., a urethane (meth)acrylate manufactured by DAICEL-ALLNEX Co., Ltd., a urethane (meth)acrylate manufactured by KANEKA CORPORATION, a urethane (meth)acrylate manufactured by Shin-Nakamura Chemical Co., Ltd., a urethane (meth)acrylate manufactured by Kyoeisha Chemical Co., Ltd., and the like can be given.

[0078] As the above urethane (meth)acrylate manufactured by Toagosei Co., Ltd., for example, M-1100, M-1200, M-1210, M-1600, and the like can be given.

[0079] As the above urethane (meth)acrylate manufactured by DAICEL-ALLNEX Co., Ltd., for example, EBECRYL 210, EBECRYL 220, EBECRYL 230, EBECRYL 270, EBECRYL 1290, EBECRYL 2220, EBECRYL 4827, EBECRYL 4842, EBECRYL 4858, EBECRYL 5129, EBECRYL 6700, EBECRYL 8402, EBECRYL 8803, EBECRYL 8804, EBECRYL 8807, EBECRYL 9260, and the like can be given.

[0080] As the urethane (meth) acrylate of the above-mentioned "Nippon Shokubai Co., Ltd.", for example, Artresin UN-330, Artresin SH-500B, Artresin UN-1200TPK, Artresin UN-1255, Artresin UN-3320HB, Artresin UN-7100, Artresin UN-9000A, Artresin UN-9000H, and the like can be given.

[0081] As the urethane (meth) acrylate of the above-mentioned "Shin Nakamura Chemical Co., Ltd.", for example, U-2HA, U-2PHA, U-3HA, U-4HA, U-6H, U-6HA, U-6LPA, U-10H, U-15HA, U-108, U-108A, U-122A, U-122P, U-324A, U-340A, U-340P, U-1084A, U-2061BA, UA-340P, UA-4000, UA-4100, UA-4200, UA-4400, UA-5201P, UA-7100, UA-7200, UA-W2A, and the like can be given.

[0082] As the urethane (meth) acrylate of the above-mentioned "Kyoeisha Chemical Co., Ltd.", for example, AH-600, AI-600, AT-600, UA-101I, UA-101T, UA-306H, UA-306I, UA-306T, and the like can be given.

[0083] The above-mentioned curable resin can contain an epoxy compound for the purpose of improving the adhesiveness and the like of the obtained sealing agent for liquid crystal display elements. As the above-mentioned epoxy compound, for example, an epoxy compound which becomes a raw material for synthesizing the above-mentioned epoxy (meth) acrylate, a partially (meth) acryl-modified epoxy compound, and the like can be given.

[0084] Note that, in the present specification, the above-mentioned partially (meth) acryl-modified epoxy compound means, for example, a compound having one or more than one epoxy group and one or more than one (meth) acryloyl group in one molecule, which can be obtained by reacting a part of the epoxy groups of an epoxy compound having two or more epoxy groups in one molecule with (meth) acryl acid.

[0085] In the case where the aforementioned (meth)acrylic compound and the aforementioned epoxy compound are contained as the aforementioned curable resin, or in the case where the aforementioned partial (meth)acrylic-modified epoxy compound is contained as the aforementioned curable resin, the ratio of the (meth)acryloyl group in the total of the (meth)acryloyl group and the epoxy group in the aforementioned curable resin is preferably 30 mol% or more and 95 mol% or less. By making the ratio of the aforementioned (meth)acryloyl group within this range, occurrence of liquid crystal contamination is suppressed, and the adhesiveness of the resulting sealing material for liquid crystal display elements becomes more excellent.

[0086] From the viewpoint of making the low liquid crystal contamination property of the resulting sealing material for liquid crystal display elements more excellent, the aforementioned curable resin preferably has a unit that is hydrogen-bonding, such as an -OH group, an -NH- group, an -NH2 group, or the like.

[0087] The aforementioned curable resin can be used alone, or two or more kinds thereof can be used in combination.

[0088] The sealing material for liquid crystal display elements of the present application can contain a thermal polymerization initiator within a range that does not interfere with the object of the present application.

[0089] As the aforementioned thermal polymerization initiator, for example, a thermal polymerization initiator composed of an azo compound, an organic peroxide, or the like can be given. Among them, a high-molecular azo initiator composed of a high-molecular azo compound is preferred.

[0090] The aforementioned thermal polymerization initiator can be used alone, or two or more kinds thereof can be used in combination.

[0091] Note that, in the present specification, the aforementioned "high-molecular azo compound" refers to a compound having an azo group and generating a radical capable of curing a (meth)acryloyloxy group by heat, with a number average molecular weight of 300 or more.

[0092] The lower limit of the number average molecular weight of the aforementioned high-molecular azo compound is preferably 1000, and the upper limit thereof is preferably 300,000. By making the number average molecular weight of the aforementioned high-molecular azo compound within this range, liquid crystal contamination can be suppressed, and the high-molecular azo compound can be easily mixed with the curable resin. The more preferred lower limit of the number average molecular weight of the aforementioned high-molecular azo compound is 5000, the more preferred upper limit thereof is 1,000,000, the further preferred lower limit thereof is 10,000, and the further preferred upper limit thereof is 90,000.

[0093] As the aforementioned high-molecular azo compound, for example, a high-molecular azo compound having a structure in which a plurality of polyalkylene oxide, polydimethylsiloxane, or the like units are linked via an azo group can be given.

[0094] As the above-mentioned high molecular azo compound having a structure in which a plurality of polyalkylene oxide or the like units are linked via an azo group, a high molecular azo compound having a polyethylene oxide structure is preferable.

[0095] As the above-mentioned high molecular azo compound, specifically, for example, a polycondensate of 4,4'-azobis(4-cyanopentanoic acid) and a polyalkylene glycol, a polycondensate of 4,4'-azobis(4-cyanopentanoic acid) and a polydimethylsiloxane having a terminal amino group, and the like can be mentioned.

[0096] As the above-mentioned commercially available product of the high molecular azo compound, for example, VPE-0201, VPE-0401, VPE-0601, VPS-0501, VPS-1001 (all of which are manufactured by Fuji Photo Film Co., Ltd. and Chong Kun Kwan Kagaku Co., Ltd.), and the like can be mentioned.

[0097] In addition, as the azo compound which is not a high molecule, for example, V-65, V-501 (both of which are manufactured by Fuji Photo Film Co., Ltd. and Chong Kun Kwan Kagaku Co., Ltd.), and the like can be mentioned.

[0098] As the above-mentioned organic peroxide, for example, a ketone peroxide, a ketal peroxide, a hydrogen peroxide, a dialkyl peroxide, an ester peroxide, a diacyl peroxide, a peroxydicarbonate, and the like can be mentioned.

[0099] The content of the above-mentioned thermal polymerization initiator is preferably 0.05 parts by weight or more and 10 parts by weight or less relative to 100 parts by weight of the above-mentioned curable resin. By making the content of the above-mentioned thermal polymerization initiator 0.05 parts by weight or more, the heat curability of the sealing material for liquid crystal display elements according to the present application becomes more excellent. By making the content of the above-mentioned thermal polymerization initiator 10 parts by weight or less, the low liquid crystal contamination property and the storage stability of the sealing material for liquid crystal display elements according to the present application become more excellent. The content of the above-mentioned thermal polymerization initiator is more preferably 0.1 parts by weight or more and 5 parts by weight or less.

[0100] The sealing material for liquid crystal display elements according to the present application can contain a thermal curing agent.

[0101] As the above-mentioned thermal curing agent, for example, an organic acid hydrazide, an imidazole derivative, an amine compound, a polyphenol-based compound, an acid anhydride, and the like can be mentioned. Among them, an organic acid hydrazide is suitably used.

[0102] The above-mentioned thermal curing agent can be used alone or in combination of two or more.

[0103] As the above-mentioned organic acid hydrazide, for example, a sebacic acid dihydrazide, an isophthalic acid dihydrazide, an adipic acid dihydrazide, a malonic acid dihydrazide, and the like can be mentioned.

[0104] As the commercially available product of the organic acid hydrazide described above, for example, there can be mentioned an organic acid hydrazide manufactured by Otsuka Chemical Co., Ltd., an organic acid hydrazide manufactured by Ajinomoto Fine-Techno Co., Ltd., and the like.

[0105] As the organic acid hydrazide manufactured by Otsuka Chemical Co., Ltd. described above, for example, there can be mentioned SDH, ADH, and the like.

[0106] As the organic acid hydrazide manufactured by Ajinomoto Fine-Techno Co., Ltd. described above, for example, there can be mentioned AJICURE VDH, AJICURE VDH-J, AJICURE UDH, AJICURE UDH-J, and the like.

[0107] The content of the thermosetting agent is preferably 1 part by weight or more and 50 parts by weight or less, relative to 100 parts by weight of the curable resin. By setting the content of the thermosetting agent within this range, the thermosetting property can be made more excellent without deteriorating the coatability and the like of the sealing material for liquid crystal display elements obtained. The content of the thermosetting agent is more preferably 30 parts by weight or less.

[0108] The sealing material for liquid crystal display elements of the present application preferably contains a filler for the purpose of improving the viscosity, improving the adhesiveness based on the stress dispersion effect, improving the linear expansion coefficient, and the like.

[0109] As the filler described above, an inorganic filler, an organic filler, or the like can be used.

[0110] As the inorganic filler described above, for example, there can be mentioned silica, talc, glass beads, asbestos, gypsum, diatomaceous earth, green earth, bentonite, montmorillonite, sericite, activated clay, alumina, zinc oxide, iron oxide, magnesium oxide, tin oxide, titanium oxide, calcium carbonate, magnesium carbonate, magnesium hydroxide, aluminum hydroxide, aluminum nitride, silicon nitride, barium sulfate, calcium silicate, and the like.

[0111] As the organic filler described above, for example, there can be mentioned polyester microparticles, polyurethane microparticles, vinyl polymer microparticles, acrylic polymer microparticles, and the like.

[0112] The filler described above can be used alone or in combination of two or more.

[0113] The content of the filler is preferably 30 parts by weight or more and 80 parts by weight or less, relative to 100 parts by weight of the curable resin. By setting the content of the filler within this range, the effect of improving the adhesiveness and the like can be made more excellent without deteriorating the coatability and the like. The content of the filler is more preferably 45 parts by weight or more and 65 parts by weight or less.

[0114] The sealing agent for liquid crystal display elements of the present application preferably contains a silane coupling agent. The above-mentioned silane coupling agent mainly functions as an adhesion aid for good adhesion of the sealing agent to a substrate or the like.

[0115] As the above-mentioned silane coupling agent, for example, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3- glycidoxypropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane or the like are suitably used. They are excellent in the effect of improving adhesion to a substrate or the like, and by chemically bonding to the curable resin, the outflow of the curable resin into the liquid crystal can be suppressed.

[0116] The above-mentioned silane coupling agent can be used alone, or two or more kinds can be used in combination.

[0117] The content of the above-mentioned silane coupling agent in the sealing agent for liquid crystal display elements of the present application of 100 parts by weight is preferably 0.1 parts by weight or more and 10 parts by weight or less. By making the content of the above-mentioned silane coupling agent within this range, the occurrence of liquid crystal contamination is suppressed, and the effect of improving adhesion becomes more excellent. The content of the above-mentioned silane coupling agent is more preferably 0.3 parts by weight or more and 5 parts by weight or less.

[0118] The sealing agent for liquid crystal display elements of the present application can further contain, as needed, a reactive diluent, a thixotropic agent, a spacer, a curing accelerator, an antifoaming agent, a leveling agent, a polymerization inhibitor or the like.

[0119] As a method of producing the sealing agent for liquid crystal display elements of the present application, for example, a method of mixing a curable resin, a photopolymerization initiator, a sensitizer and a silane coupling agent or the like added as needed using a homogenizing disperser, a homogenizing mixer, a universal mixer, a planetary mixer, a kneader, a three-roll mill or the like can be mentioned.

[0120] By incorporating electrically conductive fine particles in the sealing agent for liquid crystal display elements of the present application, a top-and-bottom conductive material can be produced.

[0121] As the above-mentioned electrically conductive fine particles, a metal sphere, electrically conductive fine particles having an electrically conductive metal layer formed on the surface of a resin fine particle or the like can be used. Among them, the electrically conductive fine particles having an electrically conductive metal layer formed on the surface of a resin fine particle are suitable because they can be electrically connected without damaging a transparent substrate or the like by virtue of the excellent elasticity of the resin fine particle.

[0122] A liquid crystal display element having a cured product of the sealing agent for liquid crystal display elements of the present application is also one of the present application.

[0123] As the liquid crystal display element of the present application, a narrow-frame design liquid crystal display element is preferred. Specifically, the width of the frame portion around the liquid crystal display portion is preferably 2 mm or less.

[0124] Further, the coating width of the sealing agent for liquid crystal display elements of the present application at the time of manufacturing the liquid crystal display element of the present application is preferably 1 mm or less.

[0125] As the method of manufacturing the liquid crystal display element of the present application, a liquid crystal dropping process is suitably used, and specifically, for example, a method having the following steps and the like can be mentioned.

[0126] First, a step of forming a frame-shaped seal pattern by coating the sealing agent for liquid crystal display elements of the present application on one of two transparent substrates having an electrode such as an ITO film and an alignment film by screen printing, dispenser coating or the like is performed. Next, a step of dropping and coating a minute drop of liquid crystal within the frame of the seal pattern of the substrate in a state where the sealing agent for liquid crystal display elements of the present application is not cured, and overlapping the other transparent substrate under vacuum is performed. Then, by performing a step of irradiating light to the seal pattern part of the sealing agent for liquid crystal display elements of the present application through a cut filter or the like, thereby making the sealing agent photocured, a liquid crystal display element can be obtained. Further, in addition to the step of making the above-mentioned sealing agent photocured, a step of heating the sealing agent to make it thermally cured can also be performed.

[0127] Effects of the Invention

[0128] According to the present application, a sealing agent for liquid crystal display elements which is excellent in visible light curability and excellent in low liquid crystal contamination can be provided. Further, according to the present application, a liquid crystal display element using the sealing agent for liquid crystal display elements can be provided. DETAILED DESCRIPTION

[0129] Hereinafter, the present application will be described in more detail by citing examples, but the present application is not limited only to these examples.

[0130] (Examples 1 to 19 and Comparative Examples 1 to 7)

[0131] The sealing agents for liquid crystal display elements of Examples 1 to 19 and Comparative Examples 1 to 7 were prepared by mixing each material using a planetary mixer after mixing, and further mixing using a three-roll machine, in accordance with the compounding ratio described in Tables 1 to 3. As the planetary mixer, a THINKY (manufactured by THINKY Corporation) was used.

[0132] Note that in Tables 1 to 3, the "absorbance at a wavelength of 400 nm" and the "absorbance at a wavelength of 450 nm" of the sensitizer mean the value of the absorbance at each wavelength when the maximum value of the absorbance in the range of 300 nm or more and 550 nm or less of the wavelength at the time of measuring the absorbance spectrum of a solution in which the sensitizer was dissolved in acetonitrile so that the concentration became 20 mg / L was set to 1.

[0133] <Evaluation>

[0134] The following evaluations were performed on each of the sealants for liquid crystal display elements obtained in the examples and comparative examples. The results are shown in Tables 1 to 3.

[0135] (Photo-curing property)

[0136] One part by weight of spacer fine particles 1 was dispersed in 100 parts by weight of each of the sealants for liquid crystal display elements obtained in the examples and comparative examples. As the spacer fine particles, Micropearl SI-H050 (manufactured by Sekisui Chemical Co., Ltd.) was used. Next, the sealant was filled in a syringe for dispensing, and after defoaming treatment, it was applied to a glass substrate using a dispenser. As the syringe for dispensing, PSY-10E (manufactured by Musashi Engineering Co., Ltd.) was used, and as the dispenser, SHOTMASTER 300 (manufactured by Musashi Engineering Co., Ltd.) was used. On the substrate on which the sealant was applied, a glass substrate of the same size was attached using a vacuum attachment device under reduced pressure of 5 Pa, to obtain a test piece. The sealant portion of the obtained test piece was irradiated with light of 100 mW / cm2for 30 seconds using a metal halide lamp through a cut filter. As the cut filter, a 340 nm cut filter that cuts light of wavelength of 340 nm or less, a 400 nm cut filter that cuts light of wavelength of 400 nm or less, a 420 nm cut filter that cuts light of wavelength of 420 nm or less, or a 440 nm cut filter that cuts light of wavelength of 440 nm or less was used. 2

[0137] For the test piece before light irradiation and the test piece after light irradiation through each cut filter, FT-IR measurement of the sealant was performed using an infrared spectrometer, and the amount of change in the peak from the (meth)acryl group was measured. As the infrared spectrometer, FTS3000 (manufactured by BIORAD Co., Ltd.) was used. A case where the peak from the (meth)acryl group after light irradiation was reduced by 85% or more was recorded as "O", a case where the peak was reduced by 75% or more and less than 85% was recorded as "O", a case where the peak was reduced by 70% or more and less than 75% was recorded as "Δ", and a case where the peak from the (meth)acryl group after light irradiation was reduced by less than 70% was recorded as "X", and the photo-curing property was evaluated.

[0138] (Low liquid crystal contamination property)

[0139] ​To a sample bottle, liquid crystal (Chisso Corporation, "JC-5001LA") 0.5 g was added, and each of the sealants for liquid crystal display elements obtained in the examples and comparative examples 0.1 g was added and shaken, and then, after heating at 120°C for 1 hour, it was returned to room temperature (25°C). On the alignment film of a glass substrate having a transparent electrode and an alignment film (Dai Nippon Ink and Chemicals, Inc., "SE7492"), each of the sealants for liquid crystal display elements obtained in the examples and comparative examples was applied in the form of a frame that delineates a square using a dispenser. Subsequently, a fine droplet of the liquid crystal taken out from the above sample bottle was dropped and applied to the entire surface of the frame on the substrate, and another glass substrate was overlaid in a vacuum. The vacuum was released, and using a metal halide lamp, light of 100 mW / cm2was irradiated through a cut filter for 30 seconds. As the cut filter, a 340 nm cut filter, a 400 nm cut filter, a 420 nm cut filter, or a 440 nm cut filter was used. Then, the sealant was heat cured at 120°C for 1 hour, and a liquid crystal display element was obtained. 2

[0140] For the obtained liquid crystal display element, using a liquid crystal physical property evaluation system Model 6254 (TOYO Corporation), an alternating current voltage of 1.0 V, 1.0 Hz was applied at 25°C, and the retention voltage after 100 milliseconds was measured, and thus the voltage retention rate of the liquid crystal was calculated. The case where the voltage retention rate was 90% or more was evaluated as "O", the case where it was 85% or more and less than 90% was evaluated as "D", the case where it was 80% or more and less than 85% was evaluated as "△", and the case where it was less than 80% was evaluated as "X", and the low liquid crystal contamination property was evaluated.

[0141]

[0142] [Table 2]

[0143]

[0144]

[0145] Industrial Applicability

[0146] According to the present application, a sealant for liquid crystal display elements that is excellent in visible light curability and low liquid crystal contamination property can be provided. In addition, according to the present application, a liquid crystal display element using the sealant for liquid crystal display elements can be provided.​

Claims

1. A sealant for liquid crystal display elements, characterized in that, It contains curing resin, photopolymerization initiator, and sensitizer. The photopolymerization initiator contains camphorquinone. When the absorbance spectrum of a solution prepared by dissolving the sensitizer in acetonitrile to a concentration of 20 mg / L was measured, and the maximum absorbance in the range of wavelengths above 300 nm and below 550 nm was set to 1, the absorbance at wavelength 400 nm was 0.1 or more, and the absorbance at wavelength 450 nm was 0.07 or more.

2. The sealant for liquid crystal display elements according to claim 1, wherein, The sensitizer has at least one structure selected from the coumarin skeleton and the acridine skeleton.

3. The sealant for liquid crystal display elements according to claim 1, wherein, The sensitizer is selected from at least one of 3-benzoyl-7-diethylaminocoumarin, 3,3-carbonylbis(7-diethylaminocoumarin), acridine-3,6-diamine, and 9,10-phenanthroquinone.

4. The sealant for liquid crystal display elements according to claim 1, 2, or 3, wherein, The sensitizer is present in a proportion of 0.1 parts by weight or more and 200 parts by weight relative to 100 parts by weight of camphorquinone.

5. A liquid crystal display element having a cured product of the sealant for liquid crystal display elements as described in claim 1, 2, 3 or 4.

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