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

Abstract

An object of the present application is to provide a sealant for liquid crystal display elements, which is excellent in visible light curability and low liquid crystal contamination, and which can suppress nozzle clogging at the time of coating. In addition, an object of the present application is to provide a liquid crystal display element using the sealant for liquid crystal display elements. The sealant for liquid crystal display elements of the present application contains a curable resin and a photopolymerization initiator, and has a gel fraction of 70% or more when irradiated with light of 100 mW / cm 2 for 30 seconds using an LED lamp having a peak top at a wavelength of 450 nm, and a gel fraction of less than 10% when irradiated with light of 400 lux for 48 hours using an LED lamp having a peak top at a wavelength of 580 nm.

Description

Technical Field

[0001] This invention relates to a sealant for liquid crystal display elements that exhibits excellent visible light curability and low liquid crystal contamination, and is capable of suppressing nozzle clogging during coating. Furthermore, this invention relates to liquid crystal display elements manufactured using this sealant. Background Technology

[0002] In recent years, as a manufacturing method for liquid crystal display elements such as liquid crystal display units, from the viewpoint of shortening production cycle time and optimizing the amount of liquid crystal used, a liquid crystal dropping process, which uses photothermal curing sealant and is disclosed in Patent Documents 1 and 2, has been adopted.

[0003] In the droplet process, firstly, a frame-shaped sealing pattern is formed on one of two transparent substrates with electrodes using a dispensing method. Next, while the sealant is not yet cured, tiny drops of liquid crystal are dropped onto the entire surface of the frame on the transparent substrate, and the other transparent substrate is immediately bonded to it. The sealed area is then pre-cured by irradiating the sealant with ultraviolet light. Finally, the liquid crystal is annealed and heated to achieve final curing, thus producing a liquid crystal display element. If the substrates are bonded under reduced pressure, liquid crystal display elements can be manufactured with extremely high efficiency; currently, this droplet process has become the mainstream method for manufacturing liquid crystal display elements.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2001-133794

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

[0008] Patent Document 3: International Publication No. 2018 / 038016 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] In today's world, with the widespread use of mobile devices equipped with LCD panels, such as mobile phones and portable game consoles, miniaturization of devices is a pressing issue. One method for miniaturization is to reduce the bezel size of the LCD display, for example, by placing the sealing portion under the black matrix (hereinafter also referred to as a narrow bezel design).

[0011] However, in narrow bezel designs, because the sealant is positioned directly below the black matrix, a problem arises if a drop-on process is used: the light irradiated during the sealant's photocuring is blocked, preventing it from reaching the sealant's interior, resulting in incomplete curing. If the sealant curing is incomplete, uncured sealant components dissolve into the liquid crystal, causing liquid crystal contamination.

[0012] Typically, ultraviolet (UV) irradiation is used to photocur sealants. However, especially in liquid crystal drop processes, since the sealant is cured after the liquid crystal is dropped, UV irradiation can cause liquid crystal degradation. Therefore, to prevent UV-induced liquid crystal degradation, a photopolymerization initiator reactive to visible light is incorporated into the sealant, and the sealant is cured by irradiation with light passing through a cutoff filter. Camphor quinone compounds and the like are disclosed as such photopolymerization initiators in Patent Document 3.

[0013] The object of this invention is to provide a sealant for liquid crystal display elements that exhibits excellent visible light curability and low liquid crystal contamination, and is capable of suppressing nozzle clogging during coating. Furthermore, the object of this invention is to provide a liquid crystal display element manufactured using this sealant.

[0014] Methods for solving problems

[0015] This disclosure 1 discloses a sealant for liquid crystal display elements, which contains a curable resin and a photopolymerization initiator.

[0016] Irradiation with 100mW / cm using an LED lamp with a peak at a wavelength of 450nm. 2 The gel fraction was over 70% after 30 seconds of light exposure, and...

[0017] The gel fraction was less than 10% after irradiating the product with 400 lux of light using an LED lamp with a peak at a wavelength of 580 nm for 48 hours.

[0018] This disclosure 2 is a liquid crystal display element having a cured product of the sealant for liquid crystal display elements of this disclosure 1.

[0019] The present invention will now be described in detail.

[0020] From the viewpoint of reducing energy loss and manufacturing costs, the inventors have researched a method for fabricating liquid crystal display elements by irradiating the sealant with an LED lamp that has a peak at a long wavelength (e.g., 450 nm) without using a cutoff filter, thereby curing the sealant. However, when using a sealant containing a camphor quinone-based compound as a photopolymerization initiator and using such an LED lamp to fabricate the liquid crystal display element, liquid crystal contamination is clearly generated.

[0021] The inventors believe that liquid crystal contamination occurs when using a sealant containing a camphor quinone compound as a photopolymerization initiator and employing an LED lamp with a peak in the long-wavelength region without a cutoff filter in the fabrication of a liquid crystal display element. This is because the camphor quinone compound has low reactivity, preventing the sealant from fully curing. Therefore, the inventors investigated using photopolymerization initiators such as titanium thiocyanate compounds, which have superior reactivity to visible light. However, when using such photopolymerization initiators, the sealant sometimes becomes clogged in the nozzle of the coating apparatus during application. Typically, when coating a sealant using a photopolymerization initiator with excellent reactivity to visible light, the coating is performed under a yellow lamp designed to prevent the photopolymerization initiator from reacting. However, the inventors believe that nozzle clogging during sealant application occurs because the photopolymerization initiator reacts even under this yellow lamp light. Therefore, the inventors investigated irradiation with a 100 mW / cm² LED lamp having a peak at 450 nm. 2 The sealant was prepared by means of a gel fraction exceeding a specific value after 30 seconds of exposure to light and a gel fraction less than a specific value after 48 hours of irradiation with 400 lux of light using an LED lamp with a peak at a wavelength of 580 nm. The results showed that a sealant for liquid crystal display elements with excellent visible light curability and low liquid crystal contamination, and capable of suppressing nozzle clogging during coating, was obtained, thus completing the present invention.

[0022] Regarding the sealant for liquid crystal display elements of the present invention, irradiation with 100mW / cm using an LED lamp having a peak at a wavelength of 450nm (hereinafter also referred to as "450nm LED lamp") is employed. 2 The gel fraction was over 70% after 30 seconds of light exposure. This was achieved by irradiating the area with a 450nm LED lamp at 100mW / cm². 2 The gel fraction was over 70% after 30 seconds of exposure to light, thus the sealant for liquid crystal display elements of the present invention exhibits excellent visible light curability and low liquid crystal contamination. Irradiation with a 450nm LED lamp at 100mW / cm² was also observed. 2 The preferred lower limit for the gel fraction after 30 seconds of light exposure is 80%, and the more preferred lower limit is 85%.

[0023] It should be noted that, in this specification, the "gel fraction" refers to the degree to which the curable resin contained in the sealant is cross-linked and polymerized. It should also be noted that fillers and other substances mixed in at this time can also be considered as substances that gel simultaneously by entering the polymer.

[0024] In addition, the above gel fraction can be calculated using the following formula.

[0025] Gel fraction (wt%) = ((G2-G0)÷(G1-G0))×100

[0026] The specific assignment is as follows.

[0027] A sealant is applied between two polyethylene terephthalate (PET) films to a thickness of 300 μm. Examples of PET films include PET5011 (manufactured by Lintec Corporation). After irradiating one side of the PET film with a specified LED lamp and a metal halide lamp, the two PET films are peeled off. If the sealant is not sticky, the cured sealant is peeled from the PET film and cut into strips of 1 cm × 2 cm. These strips are then wrapped with a 200-mesh metal mesh to prevent the sealant from releasing outside the mesh. Conversely, if the sealant is sticky, it is collected using a micro-scraper and wrapped with a 200-mesh metal mesh to prevent release outside the mesh. The weight of the metal mesh used is measured and designated as G0, and the total weight of the sealant and the metal mesh is measured and designated as G1. It should be noted that G0 is defined as 1g or more but less than 3g, and (G1-G0) is defined as 0.2g or more but less than 0.4g. Additionally, 200 mesh indicates the fineness of the mesh, meaning there are 200 metal wires per inch. After placing the sealant-coated metal mesh into screw tube No. 8 (manufactured by Maruemu), 70g of acetone was added, and the mixture was left to stand for 3 hours. The sealant-coated metal mesh was then removed from the acetone using tweezers and placed into a new screw tube No. 8 (manufactured by Maruemu). Another 70g of acetone was added, and the mixture was left to stand for another 2 hours. The sealant-coated metal mesh was then removed using tweezers and dried in an oven at 80°C under normal pressure for 2 hours. After drying, the weight of the sealant-coated metal mesh was measured and designated as G2. It should be noted that the above procedure was performed in a darkroom with a lux or less. In addition, a digital illuminance meter TM-201L (manufactured by TENMERS) was used to measure the illuminance in the working environment.

[0028] Examples of 450nm LEDs include the UELCL-P-450-X (manufactured by EYE GRAPHICS). The emission spectrum of the UELCL-P-450-X is shown below. Figure 1 .

[0029] Regarding the illuminance of the 450nm LED lamp, the illuminance was measured in mW / cm² using a UIT-θLED ultraviolet lux meter (manufactured by USHIO Electric Corporation) with the absolute value correction wavelength set to 450nm. 2 The unit is indicated.

[0030] Regarding the sealant for liquid crystal display elements of the present invention, the gel fraction when irradiated with 400 lux light for 48 hours using an LED lamp having a peak at a wavelength of 580 nm (hereinafter also referred to as a "580nm LED lamp") is less than 10%. By ensuring that the gel fraction when irradiated with 400 lux light for 48 hours using the aforementioned 580nm LED lamp is less than 10%, the sealant for liquid crystal display elements of the present invention can suppress nozzle clogging during coating. The preferred upper limit for the gel fraction when irradiated with 400 lux light for 48 hours using the aforementioned 580nm LED lamp is 7%, and a more preferred upper limit is 3%.

[0031] Examples of 580nm LEDs mentioned above include the ECOHILUX HES-YF LDG32T·Y22 / 22 (manufactured by IRISOHYAMA). The emission spectrum of the ECOHILUX HES-YF LDG32T·Y22 / 22 is shown below. Figure 2 .

[0032] The illuminance of the 580nm LED lamp will be expressed in lux (lx) when using a digital illuminance meter TM-201L (manufactured by TENMARS).

[0033] The sealant for liquid crystal display elements of the present invention contains a curable resin.

[0034] The aforementioned curable resin preferably contains (meth)acrylic acid compounds.

[0035] Examples of the aforementioned (meth)acrylate compounds include (meth)acrylate compounds, epoxy (meth)acrylates, and urethane (meth)acrylates. Among these, epoxy (meth)acrylates are preferred. Furthermore, from the viewpoint of reactivity, the aforementioned (meth)acrylate compounds preferably have two or more (meth)acryloyl groups in one molecule.

[0036] It should be noted that in this specification, "(meth)acrylic acid" refers to acrylic acid or methacrylic acid, "(meth)acrylic acid compounds" refers to compounds having a (meth)acryloyl group, and "(meth)acryloyl group" refers to an acryloyl group or a methacryloyl group. Additionally, "(meth)acrylate" refers to an acrylate or a methacrylate. Furthermore, "epoxy (meth)acrylate" refers to a compound obtained by reacting all the epoxy groups in an epoxy compound with (meth)acrylic acid.

[0037] Examples of monofunctional compounds among the aforementioned (meth)acrylate compounds include: methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, isooctyl methacrylate, isononyl methacrylate, isodecanyl methacrylate, lauryl methacrylate, isomyristyl methacrylate, stearyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 4-hydroxybutyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, dicyclopentenyl methacrylate, benzyl methacrylate, 2-methoxyethyl methacrylate, and 2-ethoxyethyl methacrylate. 2-Butoxyethyl methacrylate, 2-phenoxyethyl methacrylate, methoxyethylene glycol (meth)acrylate, methoxy polyethylene glycol (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, tetrahydrofurfuryl methacrylate, ethyl carbitol (meth)acrylate, 2,2,2-trifluoroethyl methacrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 1H,1H,5H-octafluoropentyl methacrylate, imide (meth)acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl hexahydrophthalate, 2-(meth)acryloyloxyethyl 2-hydroxypropyl phthalate, 2-(meth)acryloyloxyethyl phosphate, glycidyl methacrylate, etc.

[0038] Furthermore, examples of difunctional compounds among the aforementioned (meth)acrylate compounds include: 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, and tripropylene glycol di(meth)acrylate. Ester, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethylene oxide addition bisphenol A di(meth)acrylate, propylene oxide addition bisphenol A di(meth)acrylate, ethylene oxide addition bisphenol F di(meth)acrylate, dihydroxymethyldicyclopentadienyl di(meth)acrylate, ethylene oxide 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, etc.

[0039] In addition, examples of compounds with three or more functions among the aforementioned (meth)acrylate compounds include: trimethylolpropane tri(meth)acrylate, ethylene oxide addition trimethylolpropane tri(meth)acrylate, propylene oxide addition trimethylolpropane tri(meth)acrylate, caprolactone-modified trimethylolpropane tri(meth)acrylate, ethylene oxide addition isocyanuric acid tri(meth)acrylate, glycerol tri(meth)acrylate, propylene oxide addition glycerol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, tri(meth)acryloyloxyethyl phosphate, bis(trimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, etc.

[0040] Examples of the aforementioned epoxy (meth)acrylates include epoxy (meth)acrylates obtained by reacting an epoxy compound with (meth)acrylic acid in the presence of a basic catalyst using conventional methods.

[0041] Examples of epoxy compounds that can be used as raw materials for the synthesis of the aforementioned epoxy (meth)acrylates include: bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol S type epoxy compounds, 2,2'-diallylbisphenol 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, and diphenyl ether type epoxy compounds. Compounds, including dicyclopentadiene-type epoxy compounds, naphthalene-type epoxy compounds, phenol-aldehyde-type epoxy compounds, o-cresol-aldehyde-type epoxy compounds, dicyclopentadiene-aldehyde-type epoxy compounds, biphenyl-aldehyde-type epoxy compounds, naphthalene-phenol-aldehyde-type epoxy compounds, glycidylamine-type epoxy compounds, alkyl polyol-type epoxy compounds, rubber-modified epoxy compounds, glycidyl ester compounds, etc.

[0042] Commercially available examples of the aforementioned bisphenol A type epoxy compounds include jER828EL, jER1004 (both manufactured by Mitsubishi Chemical Corporation), and EPICLON EXA-850CRP (manufactured by DIC Corporation).

[0043] Commercially available examples of the aforementioned bisphenol F type epoxy compounds include, for example, jER806 and jER4004 (both manufactured by Mitsubishi Chemical Corporation).

[0044] Commercially available examples of the aforementioned bisphenol S-type epoxy compounds include, for example, EPICLON EXA1514 (manufactured by DIC).

[0045] Commercially available examples of the aforementioned 2,2'-diallylbisphenol A type epoxy compounds include, for example, RE-810NM (manufactured by Nippon Kayaku Co., Ltd.).

[0046] Commercially available examples of the aforementioned hydrogenated bisphenol type epoxy compounds include, for example, EPICLON EXA7015 (manufactured by DIC).

[0047] Commercially available examples of the aforementioned propylene oxide addition bisphenol A type epoxy compounds include, for example, EP-4000S (manufactured by ADEKA).

[0048] Commercially available examples of the aforementioned resorcinol-type epoxy compounds include, for example, EX-201 (manufactured by Nagase ChemteX).

[0049] Commercially available examples of the aforementioned biphenyl-type epoxy compounds include, for example, jER YX-4000H (manufactured by Mitsubishi Chemical Corporation).

[0050] Commercially available examples of the aforementioned thioether-type epoxy compounds include YSLV-50TE (manufactured by NIPPON STEELC Chemical & Material Co., Ltd.).

[0051] Commercially available examples of the aforementioned diphenyl ether type epoxy compounds include YSLV-80DE (manufactured by NIPPONSTEEL Chemical & Material Co., Ltd.).

[0052] Commercially available examples of the aforementioned dicyclopentadiene-type epoxy compounds include EP-4088S (manufactured by ADEKA).

[0053] Commercially available examples of the aforementioned naphthalene-type epoxy compounds include EPICLON HP4032 and EPICLONEXA-4700 (both manufactured by DIC).

[0054] Commercially available examples of the aforementioned phenolic aldehyde type epoxy compounds include, for example, EPICLON N-770 (manufactured by DIC).

[0055] Commercially available examples of the aforementioned o-cresol phenolic epoxy compounds include, for example, EPICLON N-670-EXP-S (manufactured by DIC).

[0056] Commercially available examples of the aforementioned dicyclopentadiene phenolic epoxy compounds include, for example, EPICLON HP7200 (manufactured by DIC).

[0057] Commercially available examples of the aforementioned biphenyl phenolic epoxy compounds include NC-3000P (manufactured by Nippon Kayaku Co., Ltd.).

[0058] Commercially available examples of the aforementioned naphthol phenolic epoxide compounds include, for example, ESN-165S (manufactured by NIPPONSTEEL Chemical & Material).

[0059] Commercially available examples of the aforementioned glycidylamine type epoxy compounds include jER630 (manufactured by Mitsubishi Chemical Corporation), EPICLON 430 (manufactured by DIC Corporation), and TETRAD-X (manufactured by Mitsubishi Gas Chemical Corporation).

[0060] Commercially available examples of the aforementioned alkyl polyol type epoxy compounds include ZX-1542 (manufactured by NIPPONSTEEL Chemical & Material), EPICLON 726 (manufactured by DIC), EPOLIGHT 80MFA (manufactured by Kyoei Chemical Co., Ltd.), and Denacol EX-611 (manufactured by Nagase ChemteX).

[0061] Commercially available examples of the aforementioned rubber-modified epoxy compounds include YR-450, YR-207 (both manufactured by NIPPON STEEL Chemical & Material), and Epolead PB (manufactured by Daicel).

[0062] Commercially available examples of the aforementioned glycidyl ester compounds include, for example, Denacol EX-147 (manufactured by NagaseChemteX).

[0063] Other commercially available epoxy compounds mentioned above include YDC-1312, YSLV-80XY, YSLV-90CR (all manufactured by NIPPON STEEL Chemical & Material), XAC4151 (manufactured by Asahi Kasei Corporation), jER1031, jER1032 (both manufactured by Mitsubishi Chemical Corporation), EXA-7120 (manufactured by DIC Corporation), and TEPIC (manufactured by Nissan Chemical Corporation).

[0064] Commercially available examples of the aforementioned epoxy (meth)acrylates include those manufactured by DAICL-ALLNEX, Shin-Nakamura Chemical Industry Co., Ltd., Kyoeisha Chemical Co., Ltd., and Nagase ChemteX.

[0065] Examples of epoxy (meth)acrylates manufactured by DAICEL-ALLNEX include EBECRYL 860, EBECRYL 3200, EBECRYL 3201, EBECRYL 3412, EBECRYL 3600, EBECRYL 3700, EBECRYL 3701, EBECRYL 3702, EBECRYL 3703, EBECRYL 3708, EBECRYL 3800, EBECRYL 6040, and EBECRYL RDX63182.

[0066] Examples of epoxy (meth)acrylates manufactured by Shin-Nakamura Chemical Industry Co., Ltd. include EA-1010, EA-1020, EA-5323, EA-5520, EA-CHD, and EMA-1020.

[0067] Examples of epoxy (meth)acrylates manufactured by Kyoei Chemical Co., Ltd. include 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, and Epoxy Ester 400EA.

[0068] Examples of epoxy (meth)acrylates manufactured by Nagase ChemteX include Denacol Acrylate DA-141, Denacol Acrylate DA-314, and Denacol Acrylate DA-911.

[0069] The aforementioned urethane (meth)acrylates can be obtained, for example, by reacting a hydroxyl-containing (meth)acrylate derivative with a polyfunctional isocyanate compound in the presence of a catalytic amount of a tin-based compound.

[0070] Examples of the aforementioned polyfunctional isocyanate compounds include: 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, norbornene diisocyanate, dimethylbiphenyl diisocyanate, phenylenediamine diisocyanate (XDI), hydrogenated XDI, lysine diisocyanate, triphenylmethane triisocyanate, tri(isocyanate phenyl)thiophosphate (Japanese: トリス(イソシアネートフェニル)チオフォスフェート), tetramethylphenylenediamine diisocyanate, and 1,6,11-undecane triisocyanate.

[0071] Alternatively, as the aforementioned polyfunctional isocyanate compound, a chain-extended polyfunctional isocyanate compound obtained by reacting a polyol with an excess of the polyfunctional isocyanate compound can also be used.

[0072] Examples of such polyols include ethylene glycol, propylene glycol, glycerin, sorbitol, trimethylolpropane, carbonate glycol, polyether glycol, polyester glycol, and polycaprolactone glycol.

[0073] Examples of the above-mentioned (meth)acrylic acid derivatives having hydroxyl groups include hydroxyalkyl mono(meth)acrylates, mono(meth)acrylates of diols, mono(meth)acrylates or di(meth)acrylates of triols, epoxy (meth)acrylates, etc.

[0074] Examples of the above-mentioned mono(meth)acrylate hydroxyalkyl esters include 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 2-hydroxybutyl(meth)acrylate, and 4-hydroxybutyl(meth)acrylate.

[0075] Examples of the aforementioned diols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and polyethylene glycol.

[0076] Examples of the aforementioned triols include trimethylolethane, trimethylolpropane, and glycerol.

[0077] Examples of the aforementioned epoxy (meth)acrylates include, for example, bisphenol A type epoxy acrylates.

[0078] Commercially available products among the aforementioned urethane (meth)acrylates include, for example, urethane (meth)acrylates manufactured by Toa Synthetic Co., Ltd., urethane (meth)acrylates manufactured by DAICL-ALLNEX Co., Ltd., urethane (meth)acrylates manufactured by Negami Kogyo Co., Ltd., urethane (meth)acrylates manufactured by Shin-Nakamura Chemical Co., Ltd., and urethane (meth)acrylates manufactured by Kyoeisha Chemical Co., Ltd.

[0079] Examples of urethane (meth) acrylates manufactured by the aforementioned Dong-A Synthetic Co., Ltd. include M-1100, M-1200, M-1210, and M-1600.

[0080] Examples of urethane (meth)acrylates manufactured by DAICEL-ALLNEX include EBECRYL210, EBECRYL220, EBECRYL230, EBECRYL270, EBECRYL1290, EBECRYL2220, EBECRYL4827, EBECRYL4842, EBECRYL4858, EBECRYL5129, EBECRYL6700, EBECRYL8402, EBECRYL8803, EBECRYL8804, EBECRYL8807, and EBECRYL9260.

[0081] Examples of urethane (meth)acrylates manufactured by the aforementioned Nekami Kogyo Co., Ltd. include Artresin UN-330, Artresin SH-500B, Artresin UN-1200TPK, Artresin UN-1255, Artresin UN-3320HB, Artresin UN-7100, Artresin UN-9000A, and Artresin UN-9000H.

[0082] Examples of urethane (meth)acrylates manufactured by Shin-Nakamura Chemical Industry Co., Ltd. include 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, and UA-W2A.

[0083] Examples of urethane (meth)acrylates manufactured by Kyoeisha Chemical Co., Ltd. include AH-600, AI-600, AT-600, UA-101I, UA-101T, UA-306H, UA-306I, and UA-306T.

[0084] For purposes such as improving the adhesion of the sealant for the obtained liquid crystal display element, the aforementioned curable resin may contain an epoxy compound. Examples of such epoxy compounds include epoxy compounds that serve as raw materials for synthesizing the aforementioned epoxy (meth)acrylate, and partially (meth)acrylate-modified epoxy compounds.

[0085] It should be noted that, in this specification, the aforementioned (meth)acrylic acid modified epoxy compound refers to, for example, a compound having one or more epoxy groups and one (meth)acryloyl group in one molecule, obtained by reacting a portion of the epoxy groups of an epoxy compound having two or more epoxy groups in one molecule with (meth)acrylic acid.

[0086] When the above-mentioned (meth)acrylic acid compound and the above-mentioned epoxy compound are used as the curable resin, or when the above-mentioned partially (meth)acrylic acid modified epoxy compound is used as the curable resin, it is preferable that the ratio of (meth)acryloyl groups in the total (meth)acryloyl groups and epoxy groups in the curable resin is 30 mol% or more and 95 mol% or less. By keeping the ratio of (meth)acryloyl groups within this range, the occurrence of liquid crystal contamination is suppressed, and the adhesion of the resulting sealant for liquid crystal display elements becomes more excellent.

[0087] From the viewpoint of making the sealant for the obtained liquid crystal display element have better low liquid crystal contamination, the above-mentioned curable resin preferably has units with hydrogen bonding such as -OH group, -NH- group, and -NH2 group.

[0088] The above-mentioned curing resins can be used alone or in combination of two or more.

[0089] The sealant for liquid crystal display elements of the present invention contains a photopolymerization initiator.

[0090] Regarding the use of the aforementioned 450nm LED lamp to irradiate at 100mW / cm² 2 The gel fraction after 30 seconds of light exposure and the gel fraction after 48 hours of irradiation with 400 lux of light using the aforementioned 580nm LED lamp can be adjusted by changing the type and proportion of the aforementioned photopolymerization initiator and the combination of the aforementioned photopolymerization initiator and the sensitizer described below.

[0091] As the aforementioned photopolymerization initiator, it is easy to irradiate with a 450nm LED lamp at a rate of 100mW / cm². 2 From the perspective of adjusting the gel fraction after 30 seconds of light exposure and the gel fraction after 48 hours of irradiation with 400 lux of light using the aforementioned 580nm LED lamp to the range described above, the compounds shown in formulas (1-1) to (1-3) below are preferred. Furthermore, when included in combination with the sensitizer described later, camphorquinone is also preferred as the aforementioned photopolymerization initiator.

[0092] [Chemical Formula 1]

[0093]

[0094] The preferred lower limit for the content of the photopolymerization initiator relative to 100 parts by weight of the curable resin is 0.3 parts by weight, and the preferred upper limit is 10 parts by weight. By making the content of the photopolymerization initiator 0.3 parts by weight or more, the visible light curability and low liquid crystal contamination of the resulting sealant for liquid crystal display elements are improved. By making the content of the photopolymerization initiator 10 parts by weight or less, the low liquid crystal contamination of the resulting sealant for liquid crystal display elements is improved. The more preferred lower limit for the content of the photopolymerization initiator is 0.5 parts by weight, and the more preferred upper limit is 4 parts by weight.

[0095] The sealant for liquid crystal display elements of the present invention may contain a sensitizer.

[0096] When using camphorquinone as the photopolymerization initiator, the sensitizer can be easily adjusted to 100 mW / cm² when irradiated with the 450 nm LED lamp by combining it with camphorquinone. 2 The gel fraction after 30 seconds of light exposure and the gel fraction after 48 hours of exposure to 400 lux of light using the aforementioned 580nm LED lamp.

[0097] As the aforementioned sensitizer, it is easily effective when used in combination with camphorquinone, thereby reducing the irradiation effect of a 450nm LED lamp irradiated with 100mW / cm². 2 Based on the angle of adjusting the gel fraction at 30 seconds of light and the gel fraction at 48 hours of light irradiation with the above-mentioned 580nm LED lamp to the above-mentioned range, the compounds shown in the following formula (2-1) and the compounds shown in the following formula (2-2) are preferred.

[0098] [Chemical Formula 2]

[0099]

[0100] The preferred lower limit for the content of the sensitizer relative to 100 parts by weight of the curable resin is 0.001 parts by weight, and the preferred upper limit is 0.5 parts by weight. By setting the content of the sensitizer within this range, the visible light curability and low liquid crystal contamination of the resulting sealant for liquid crystal display elements become more excellent, and the effect of suppressing nozzle clogging during coating becomes more excellent. The more preferred lower limit for the content of the sensitizer is 0.005 parts by weight, and the more preferred upper limit is 0.1 parts by weight.

[0101] The sealant for liquid crystal display elements of the present invention may contain a thermal polymerization initiator to a extent that does not impair the purpose of the present invention.

[0102] Examples of thermal polymerization initiators include those composed of azo compounds and organic peroxides. Among these, polymeric azo initiators composed of high-molecular-weight azo compounds are preferred.

[0103] The above-mentioned thermal polymerization initiators can be used alone or in combination of two or more.

[0104] It should be noted that, in this specification, the term "high molecular weight azo compound" refers to a compound having an azo group and generating a free radical capable of curing (meth)acryloyloxy through heat, with a number average molecular weight of 300 or more.

[0105] The preferred lower limit for the number-average molecular weight of the aforementioned azo polymer is 1000, and the preferred upper limit is 300,000. By ensuring that the number-average molecular weight of the aforementioned azo polymer is within this range, liquid crystal contamination can be suppressed, and it can be easily mixed with the curable resin. A more preferred lower limit for the number-average molecular weight of the aforementioned azo polymer is 5000, a more preferred upper limit is 100,000, a further preferred lower limit is 10,000, and a further preferred upper limit is 90,000.

[0106] Examples of such polymeric azo compounds include polymeric azo compounds having a structure in which multiple polyepoxide, polydimethylsiloxane, or other units are bonded together via azo groups.

[0107] As for the aforementioned polymeric azo compound having a structure in which multiple polyoxyalkylene units are bonded together via azo groups, a polymeric azo compound having a polyoxyethylene structure is preferred.

[0108] Specifically, examples of the aforementioned high molecular weight azo compounds include: condensation polymers of 4,4'-azobis(4-cyanovaleric acid) and polyalkylene glycols, and condensation polymers of 4,4'-azobis(4-cyanovaleric acid) and polydimethylsiloxanes having terminal amino groups.

[0109] Commercially available examples of the aforementioned high molecular weight azo compounds include VPE-0201, VPE-0401, VPE-0601, VPS-0501, and VPS-1001 (all manufactured by Fujifilm and Kojun Pharmaceutical Co., Ltd.).

[0110] In addition, examples of azo compounds that are not high molecular weight include V-65 and V-501 (both manufactured by Fujifilm and Kojun Pharmaceutical Co., Ltd.).

[0111] Examples of the aforementioned organic peroxides include peroxide ketones, peroxide ketals, hydrogen peroxide, dialkyl peroxides, peroxide esters, diacyl peroxides, and peroxydicarbonates.

[0112] The preferred lower limit for the content of the thermal polymerization initiator relative to 100 parts by weight of the curable resin is 0.05 parts by weight, and the preferred upper limit is 10 parts by weight. By making the content of the thermal polymerization initiator 0.05 parts by weight or more, the thermosetting properties of the sealant for liquid crystal display elements of the present invention are improved. By making the content of the thermal polymerization initiator 10 parts by weight or less, the low liquid crystal contamination and storage stability of the sealant for liquid crystal display elements of the present invention are improved. The more preferred lower limit for the content of the thermal polymerization initiator is 0.1 parts by weight, and the more preferred upper limit is 5 parts by weight.

[0113] The sealant for liquid crystal display elements of the present invention may contain a thermosetting agent.

[0114] Examples of thermosetting agents include organic acid hydrazides, imidazole derivatives, amine compounds, polyphenolic compounds, and acid anhydrides. Among these, organic acid hydrazides are particularly suitable.

[0115] The above-mentioned thermosetting agents can be used alone or in combination of two or more.

[0116] Examples of the aforementioned organic acid hydrazides include sebacic acid dihydrazide, isophthalic acid dihydrazide, adipic acid dihydrazide, malonic acid dihydrazide, etc.

[0117] Commercially available examples of the aforementioned organic acid hydrazides include those manufactured by Otsuka Chemical Co., Ltd., and those manufactured by Ajinomoto Fine-Techno Co., Ltd.

[0118] Examples of organic acid hydrazides manufactured by Otsuka Chemical Co., Ltd. include SDH and ADH.

[0119] Examples of organic acid hydrazides manufactured by Ajinomoto Fine-Techno include AJICURE VDH, AJICURE VDH-J, AJICURE UDH, and AJICURE UDH-J.

[0120] The preferred lower limit for the content of the thermosetting agent relative to 100 parts by weight of the curable resin is 1 part by weight, and the preferred upper limit is 50 parts by weight. By keeping the content of the thermosetting agent within this range, the thermosetting properties can be improved without deteriorating the coatability, etc., of the resulting sealant for liquid crystal display elements. A more preferred upper limit for the content of the thermosetting agent is 30 parts by weight.

[0121] The sealant for liquid crystal display elements of the present invention preferably contains fillers for purposes such as increasing viscosity, improving adhesion based on stress dispersion effect, and improving coefficient of linear expansion.

[0122] Inorganic fillers or organic fillers can be used as the fillers mentioned above.

[0123] Examples of inorganic fillers mentioned above include silica, talc, glass beads, asbestos, gypsum, diatomaceous earth, chlorophyll, 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, and calcium silicate.

[0124] Examples of organic fillers mentioned above include polyester microparticles, polyurethane microparticles, vinyl polymer microparticles, and acrylic polymer microparticles.

[0125] The above-mentioned filler also has the effect of being irradiated with a 450nm LED lamp at a power of 100mW / cm². 2 The effect of enhancing light scattering and increasing gel fraction when light is applied for 30 seconds is preferred. In particular, organic fillers are preferred from the viewpoint that they can also ensure light transmittance compared to inorganic fillers.

[0126] The above fillers can be used alone or in combination of two or more.

[0127] The preferred lower limit for the content of the filler relative to 100 parts by weight of the curable resin is 10 parts by weight, and the preferred upper limit is 60 parts by weight. By keeping the content of the filler within this range, the effects of improving adhesion are made more superior without deteriorating coatability. The more preferred lower limit for the content of the filler is 20 parts by weight, and the more preferred upper limit is 50 parts by weight.

[0128] The sealant for liquid crystal display elements of the present invention preferably contains a silane coupling agent. The aforementioned silane coupling agent primarily functions as an adhesive aid for effectively bonding the sealant to the substrate or similar material.

[0129] As the aforementioned silane coupling agents, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, and 3-isocyanate-propyltrimethoxysilane are suitable examples. They excel in improving adhesion to substrates and the like, and by chemically bonding with the curable resin, they can suppress the outflow of the curable resin into the liquid crystal.

[0130] The above-mentioned silane coupling agents can be used alone or in combination of two or more.

[0131] The preferred lower limit of the content of the silane coupling agent in 100 parts by weight of the sealant for liquid crystal display elements of the present invention is 0.1 parts by weight, and the preferred upper limit is 10 parts by weight. By keeping the content of the silane coupling agent within this range, the occurrence of liquid crystal contamination is suppressed, and the effect of improving adhesion becomes more excellent. The more preferred lower limit of the content of the silane coupling agent is 0.3 parts by weight, and the more preferred upper limit is 5 parts by weight.

[0132] The sealant for liquid crystal display elements of the present invention may further contain additives such as reactive diluents, thixotropic agents, spacers, curing accelerators, defoamers, leveling agents, and polymerization inhibitors as needed.

[0133] As a method for manufacturing the sealant for the liquid crystal display element of the present invention, examples include: using a homogenizing disperser, homogenizing mixer, universal mixer, planetary mixer, kneader, three-roll mill, or other mixers to mix a curable resin, a photopolymerization initiator and a sensitizer, and a silane coupling agent added as needed.

[0134] By incorporating conductive microparticles into the sealant for liquid crystal display elements of the present invention, it is possible to manufacture a material with both vertical and horizontal conductivity.

[0135] As the aforementioned conductive particles, metal spheres or conductive particles with a conductive metal layer formed on the surface of resin particles can be used. Among these, conductive particles with a conductive metal layer formed on the surface of resin particles are suitable because they can achieve conductive connections without damaging the transparent substrate, thanks to the excellent elasticity of the resin particles.

[0136] A liquid crystal display element having a cured form of the sealant for liquid crystal display elements of the present invention is also one of the present inventions.

[0137] As the liquid crystal display element of the present invention, a liquid crystal display element with a narrow bezel design is preferred. Specifically, the width of the frame portion surrounding the liquid crystal display unit is preferably 2 mm or less.

[0138] Furthermore, the coating width of the sealant for the liquid crystal display element of the present invention is preferably 1 mm or less when manufacturing the liquid crystal display element of the present invention.

[0139] As a method for manufacturing the liquid crystal display element of the present invention, a liquid crystal droplet process is suitable. Specifically, for example, a method having the following steps can be cited.

[0140] First, a process is performed in which the sealant for liquid crystal display elements of the present invention is applied to one of two transparent substrates having electrodes such as ITO thin films and alignment films to form a frame-shaped sealing pattern by screen printing, dispensing, or other methods. Next, a process is performed in which tiny droplets of liquid crystal are applied onto the frame of the sealing pattern on the substrate while the sealant for liquid crystal display elements of the present invention is still uncured, and then another transparent substrate is superimposed under vacuum. Then, a liquid crystal display element can be obtained by irradiating the sealing pattern portion of the sealant for liquid crystal display elements of the present invention with light through a cutoff filter or the like, thereby photocuring the sealant. In addition to the above-described photocuring process, a process of heating the sealant to thermally cure it can also be performed.

[0141] Invention Effects

[0142] According to the present invention, a sealant for liquid crystal display elements is provided that exhibits excellent visible light curability and low liquid crystal contamination, and is capable of suppressing nozzle clogging during coating. Furthermore, according to the present invention, a liquid crystal display element manufactured using this sealant for liquid crystal display elements is provided. Attached Figure Description

[0143] Figure 1 This is the emission spectrum of UELCL-P-450-X.

[0144] Figure 2 This is the emission spectrum of ECOHILUX HES-YF LDG32T·Y22 / 22. Detailed Implementation

[0145] The present invention will be described in more detail below with reference to specific embodiments, but the present invention is not limited to these embodiments.

[0146] (Synthesis of the compound shown in formula (1-1))

[0147] Five parts by weight of N-ethylcarbazole, 2.81 parts by weight of 2,5-thiophene dicarboxylate chloride, and 3.76 parts by weight of aluminum chloride were added to 40 mL of dichloromethane and stirred overnight at room temperature. Two parts by weight of acetyl chloride and 3.76 parts by weight of aluminum chloride were added to the resulting reaction solution, and the mixture was stirred further at room temperature for 4 hours. The resulting reaction solution was then injected into ice water, and the organic layer was extracted with ethyl acetate. The extracted solution was washed with saturated sodium bicarbonate aqueous solution and brine, dried over anhydrous magnesium sulfate, and concentrated to give product (A1).

[0148] Three parts by weight of the obtained product (A1), 0.76 parts by weight of ammonium hydroxychloride, and 0.86 parts by weight of pyridine were added to 30 mL of ethanol, and the mixture was stirred under reflux for 10 hours. The resulting reaction solution was then poured into ice water and filtered. The filtrate was washed with water, dissolved in ethyl acetate, dried over anhydrous magnesium sulfate, and concentrated to obtain product (B1).

[0149] 1.5 parts by weight of the obtained product (B1) were dissolved in 25 parts by weight of N,N-dimethylformamide, and then 0.59 parts by weight of acetyl chloride were added. While cooling the resulting solution to below 10°C, 0.78 parts by weight of triethylamine were added dropwise, and the mixture was stirred at room temperature for 4 hours. The resulting reaction solution was injected into water and filtered. The filtrate was purified by silica gel column chromatography using a mixed solvent of dichloromethane and hexane (dichloromethane:hexane = 2:1) to obtain the compound shown in formula (1-1) above.

[0150] It should be noted that the structure of the compound shown in formula (1-1) above is obtained through... 1 H-NMR, 13 Confirmed by C-NMR and FT-IR.

[0151] (Synthesis of the compounds shown in formula (1-2))

[0152] Five parts by weight of N-(2-ethylhexyl)carbazole, 2.81 parts by weight of 2,5-thiophene dicarboxylate chloride, and 3.76 parts by weight of aluminum chloride were added to 40 mL of dichloromethane and stirred overnight at room temperature. Two parts by weight of acetyl chloride and 3.76 parts by weight of aluminum chloride were added to the resulting reaction solution, and the mixture was stirred further at room temperature for 4 hours. The resulting reaction solution was then injected into ice water, and the organic layer was extracted with ethyl acetate. The extracted solution was washed with saturated sodium bicarbonate aqueous solution and brine, dried over anhydrous magnesium sulfate, and concentrated to give product (A2).

[0153] Three parts by weight of the obtained product (A2), 0.76 parts by weight of ammonium hydroxychloride, and 0.86 parts by weight of pyridine were added to 30 mL of ethanol, and the mixture was refluxed and stirred for 10 hours. The resulting reaction solution was then poured into ice water and filtered. The filtrate was washed with water, dissolved in ethyl acetate, dried over anhydrous magnesium sulfate, and concentrated to obtain product (B2).

[0154] 1.5 parts by weight of the obtained product (B2) were dissolved in 25 parts by weight of N,N-dimethylformamide, and then 0.59 parts by weight of acetyl chloride were added. While cooling the resulting solution to below 10°C, 0.78 parts by weight of triethylamine were added dropwise, and the mixture was stirred at room temperature for 4 hours. The resulting reaction solution was injected into water and filtered. The filtrate was purified by silica gel column chromatography using a mixed solvent of dichloromethane and hexane (dichloromethane:hexane = 2:1) to obtain the compound shown in formula (1-2) above.

[0155] It should be noted that the structure of the compound shown in formula (1-2) above is obtained through... 1 H-NMR, 13 Confirmed by C-NMR and FT-IR.

[0156] (Synthesis of the compounds shown in formulas (1-3))

[0157] Five parts by weight of ethyl 3-(9H-carbazole-9-yl)propionate, 2.64 parts by weight of hexanoyl chloride, and 2.62 parts by weight of aluminum chloride were added to 80 mL of dichloromethane and stirred overnight at room temperature. 1.84 parts by weight of 2,5-thiophenecarboxylic acid chloride and 5.24 parts by weight of aluminum chloride were added to the resulting reaction solution, and the mixture was stirred further at room temperature for 4 hours. The resulting reaction solution was then injected into ice water, and the organic layer was extracted with ethyl acetate. The extracted solution was washed with saturated aqueous sodium bicarbonate solution and brine, dried over anhydrous sodium sulfate, and concentrated to give product (A3).

[0158] To 4.0 parts by weight of product (A3) in 20 mL of ethanol, 2.77 parts by weight of 20% sodium hydroxide aqueous solution were added, and the mixture was refluxed for 3 hours. After the reaction was complete, 50 mL of water was added, and the solution was adjusted to acidity with concentrated hydrochloric acid. The mixture was then extracted with ethyl acetate. The ethyl acetate layer was washed with water and brine, dried over anhydrous sodium sulfate, and concentrated to obtain product (B3).

[0159] Three parts by weight of the obtained product (B3), 0.58 parts by weight of ammonium hydroxide, and 0.65 parts by weight of pyridine were added to 30 mL of ethanol, and the mixture was refluxed and stirred for 10 hours. The resulting reaction solution was then poured into ice water and filtered. The filtrate was washed with water, dissolved in ethyl acetate, dried over anhydrous sodium sulfate, and concentrated to obtain product (C3).

[0160] 1.5 parts by weight of the obtained product (C3) were dissolved in 20 parts by weight of N,N-dimethylformamide, and then 0.45 parts by weight of acetyl chloride were added. While cooling the resulting solution to below 10°C, 0.59 parts by weight of triethylamine were added dropwise, and the mixture was stirred at room temperature for 4 hours. The resulting reaction solution was injected into water and filtered. The compounds were separated by silica gel column chromatography, thus yielding the compounds represented by formulas (1-3) above.

[0161] It should be noted that the structure of the compound shown in formula (1-3) above is obtained through... 1 H-NMR, 13 Confirmed by C-NMR and FT-IR.

[0162] (Examples 1-10 and Comparative Examples 1-6)

[0163] Following the mixing ratios described in Tables 1 and 2, the materials were mixed using a planetary mixer, and then further mixed using a three-roll mill to prepare the sealants for liquid crystal display elements of Examples 1-10 and Comparative Examples 1-6. A deaerator (manufactured by THINKY Corporation) was used as the planetary mixer. The obtained sealants for liquid crystal display elements were pretreated by deaerating them using an ARV-310LED (manufactured by THINKY Corporation).

[0164] A sealant for liquid crystal display elements was applied between two polyethylene terephthalate (PET) films (manufactured by Lintec Corporation, "PET5011") to a thickness of 300 μm. The sealant was then irradiated from one side of the PET film using a 450 nm LED lamp at 100 mW / cm². 2After 30 seconds of exposure to light, the two PET films are peeled off. If the sealant is not sticky, the cured sealant is peeled from the PET film and cut into strips of 1cm x 2cm. These strips are then wrapped with a 200-mesh metal mesh to prevent sealant release outside the mesh grids. Conversely, if the sealant is sticky, it is collected using a micro-scraper and wrapped with a 200-mesh metal mesh to prevent release outside the mesh grids. The weight of the metal mesh used is measured and designated as G0, and the total weight of the sealant and the metal mesh is measured and designated as G1. It should be noted that G0 is defined as 1g or more but less than 3g, and (G1-G0) is defined as 0.2g or more but less than 0.4g. The metal mesh wrapped with sealant is then placed into a screw-type tube No. 8 (manufactured by Maruemu), and 70g of acetone is added. The tube is left to stand for 3 hours. The metal mesh containing the sealant, present in acetone, was removed with tweezers and placed into a new screw-type tube No. 8 (manufactured by Maruemu). 70g of fresh acetone was then added to the tube, and the mixture was allowed to stand for another 2 hours. The sealant-coated metal mesh was then removed with tweezers and dried in an oven at 80°C under normal pressure for 2 hours. After drying, the weight of the sealant-coated metal mesh was measured and designated as G2. It should be noted that the above procedure was performed in a darkroom with an illuminance of less than 1 lux. Furthermore, the illuminance of the working environment was measured using a TENMARS TM-201L digital illuminance meter (manufactured by TENMARS). The gel fraction was determined by substituting the obtained values ​​of G0 to G2 into the above formula.

[0165] As a 450nm LED light, UELCL-P-450-X (manufactured by EYE GRAPHICS) is used.

[0166] In addition, a 580nm LED lamp was used instead of a 450nm LED lamp, and the sealant was irradiated with 400 lux of light for 48 hours. The gel fraction of the sealant after irradiation was also measured. The 580nm LED lamp used was ECOHILUX HES-YF LDG32T·Y22 / 22 (manufactured by IRIS OHYAMA).

[0167] Furthermore, a metal halide lamp was used instead of a 450nm LED lamp, and the light was irradiated at 100mW / cm² through a cutoff filter (340nm cutoff filter) that blocks light below 340nm. 2 The sealant was exposed to light for 30 seconds, and the gel fraction was measured similarly after light irradiation. It should be noted that for the sealants for liquid crystal display elements obtained in Examples 7, 9, and 10, the gel fraction was not measured under 100mW / cm light irradiation through a 340nm cutoff filter. 2 The gel fraction after 30 seconds of light exposure.

[0168] The obtained gel fractions are shown in Tables 1 and 2.

[0169] <Evaluation>

[0170] The sealants used to obtain the liquid crystal display elements in the examples and comparative examples were evaluated as follows. The results are shown in Tables 1 and 2.

[0171] (Nozzle blockage)

[0172] Each liquid crystal display element obtained in the examples and comparative examples was filled with sealant into a dispensing syringe, and after degassing, a nozzle was provided on the syringe. Next, the syringe with the nozzle was placed in a dispenser. To fill the nozzle tip with sealant, compressed air was applied to the syringe to cause the sealant to be ejected from the nozzle tip. Then, the compressed air was stopped, and the nozzle tip was wiped with BEMCOT.

[0173] The syringe was depressurized to a pressure that prevented the sealant from dripping from the nozzle tip and from being lost from the nozzle tip. The syringe was then left to stand for 48 hours with backflow. Then, a pressure of 100 kPa was applied to the syringe. The presence of sealant ejected from the nozzle tip was recorded as "○", and the absence of ejection was recorded as "×", thus evaluating nozzle blockage.

[0174] The syringe used for dispensing was PSY-10EU-OR (manufactured by Musashi Engineering Co., Ltd.), the nozzle used was HN-0.3N (manufactured by Musashi Engineering Co., Ltd.), and the dispenser used was SHOTMASTER300 (manufactured by Musashi Engineering Co., Ltd.). This evaluation was conducted under 400 lux light irradiation using a 580 nm LED lamp. The 580 nm LED lamp used was ECOHILUX HES-YF LDG32T·Y22 / 22 (manufactured by IRISOHYAMA Co., Ltd.), and the illuminance was measured using TM-201L (manufactured by TENMARS Co., Ltd.).

[0175] (Low liquid crystal contamination)

[0176] 0.5 g of negative liquid crystal (manufactured by JNC Petrochemical Co., Ltd., "JC-7129XX") and 0.1 g of sealant for each liquid crystal display element obtained in the examples and comparative examples were added to a sample vial. After shaking, the vial was heated at 120°C for 1 hour and then allowed to return to room temperature (25°C). The sealant for each liquid crystal display element obtained in the examples and comparative examples was applied to the alignment film of a glass substrate having a transparent electrode and an alignment film (manufactured by Nissan Chemical Co., Ltd., "RB-089") in a square grid pattern using a dispenser. The sealant application was performed under light of less than 1 lux using a 580 nm LED lamp. An ECOHILUX HES-YF LDG32T·Y22 / 22 (manufactured by IRIS OHYAMA Co., Ltd.) was used as the 580 nm LED lamp. Next, tiny droplets of liquid crystal taken from the sample vial were applied to the entire surface of the grid pattern on the substrate, and another glass substrate was superimposed under vacuum. The vacuum was released, and the substrate was irradiated with a 450 nm LED lamp at 100 mW / cm². 2 The light was applied for 30 seconds. A UELCL-P-450-X (manufactured by EYE GRAPHICS) was used as the 450nm LED. Then, the sealant was heat-cured at 120°C for 1 hour to obtain the liquid crystal display element.

[0177] For the obtained liquid crystal display element, a liquid crystal property evaluation system (TOYO Corporation, "Type 6254") was used. A 5V, 1Hz AC voltage was applied at 25°C, and the holding voltage was measured after 1 second. The voltage holding rate of the liquid crystal was calculated from this. A voltage holding rate of 95% or higher was marked with "◎", 80% or higher but less than 95% was marked with "○", and less than 80% was marked with "×". Low liquid crystal contamination was evaluated.

[0178]

[0179]

[0180] Industrial availability

[0181] According to the present invention, a sealant for liquid crystal display elements is provided that exhibits excellent visible light curability and low liquid crystal contamination, and is capable of suppressing nozzle clogging during coating. Furthermore, according to the present invention, a liquid crystal display element manufactured using this sealant for liquid crystal display elements is provided.

Claims

1. A sealant for liquid crystal display elements, characterized in that, It contains a curable resin and a photopolymerization initiator. The photopolymerization initiator is a compound represented by formula (1-1), formula (1-2), or formula (1-3); or, the photopolymerization initiator is camphorquinone and the sealant for the liquid crystal display element contains a compound represented by formula (2-1) or formula (2-2) as a sensitizer. Irradiation with 100mW / cm² using an LED lamp with a peak at a wavelength of 450nm. 2 The sealant, after being exposed to light for 30 seconds, was wrapped in a 200-mesh metal mesh, left to stand in acetone for 3 hours, and then dried. The resulting gel content, as shown in the following formula, was over 70%. The sealant, after being irradiated with 400 lux of light by an LED lamp with a peak at 580 nm for 48 hours, was wrapped in a 200-mesh metal mesh, left to stand in acetone for 3 hours, and allowed to dry until the gel fraction was less than 10%. Gel fraction (weight %) = ((G2-G0) ÷ (G1-G0)) × 100 In the formula, G0 is the weight of the metal mesh, G1 is the total weight of the sealant and the metal mesh when the sealant is wrapped in the metal mesh, and G2 is the weight of the metal mesh containing the dried sealant. 。 2. A liquid crystal display element having a cured product of the sealant for liquid crystal display elements as described in claim 1.

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