TWI707945B - Sealant for liquid crystal display element, vertical conduction material, and liquid crystal display element - Google Patents

Abstract

The object of the present invention is to provide a sealing compound for liquid crystal display elements which is excellent in photocurability and can suppress liquid crystal contamination. In addition, an object of the present invention is to provide an upper and lower conduction material and a liquid crystal display element using this sealing compound for liquid crystal display elements.

The present invention is a sealing compound for liquid crystal display elements, which contains a curable resin and a photoradical polymerization initiator, and the photoradical polymerization initiator contains a compound represented by the following formula (1-1) and / Or a compound represented by the following formula (1-2).

In the formula (1-1), X represents an alkyl group with 1 to 8 carbon atoms, or a 2-cyclopentylethyl group in which at least one hydrogen of the cyclopentyl ring can be substituted by a methyl group or an ethyl group, and R represents a methyl group Or ethyl.

In formula (1-2), Y represents an alkyl group with 2 to 8 carbon atoms, or a 2-cyclopentylethyl group in which at least one hydrogen of the cyclopentyl ring can be substituted by a methyl group or an ethyl group, and R represents a methyl group Or ethyl.

Description

Sealant for liquid crystal display element, vertical conduction material, and liquid crystal display element

The present invention relates to a sealant for liquid crystal display elements which is excellent in photocurability and can suppress liquid crystal contamination. In addition, the present invention relates to an upper and lower conduction material and a liquid crystal display element using this sealant for liquid crystal display elements.

In recent years, as a method for manufacturing liquid crystal display elements such as liquid crystal display units, from the viewpoints of shortening the pitch time and optimizing the amount of liquid crystal used, what is known as the one disclosed in Patent Document 1 and Patent Document 2 is used. It is the liquid crystal dropping method of the drop processing method. This method uses a light-heat combination hardening type sealant containing a curable resin, a photopolymerization initiator, and a thermosetting agent.

In the drop processing method, first, a rectangular sealing pattern is formed by dispensing on one of two substrates with electrodes. Then, in a state where the sealant is not hardened, droplets of liquid crystal are dropped into the sealing frame of the substrate, and another substrate is superimposed under vacuum, and the sealing part is irradiated with light such as ultraviolet rays to temporarily harden. After that, heating is performed for main curing, and a liquid crystal display element is produced. At present, this drop processing method has become the mainstream of the manufacturing method of liquid crystal display elements.

However, with the popularization of various mobile devices with LCD panels, such as mobile phones and portable game consoles, miniaturization of the devices is the most demanding issue. As a method of miniaturization of the device, the narrowing of the edge of the liquid crystal display can be cited. For example, the position of the sealing part is being arranged in black. Operation under the color matrix (hereinafter, also referred to as narrow-edge design).

However, since the sealant is arranged directly under the black matrix in the narrow-edge design, if the drop processing method is performed, the light irradiated when the sealant is photocured is blocked, and the light is difficult to reach the inside of the sealant. With the conventional sealant, the hardening becomes insufficient. If the curing of the sealant becomes insufficient in this way, there is a problem that the uncured sealant component elutes into the liquid crystal, and liquid crystal contamination is likely to occur.

Prior art literature

Patent literature

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

Patent Document 2: International Publication No. 02/092718

The object of the present invention is to provide a sealing compound for liquid crystal display elements which is excellent in photocurability and can suppress liquid crystal contamination. In addition, an object of the present invention is to provide an upper and lower conduction material and a liquid crystal display element using this sealing compound for liquid crystal display elements.

The present invention is a sealing compound for liquid crystal display elements, which contains a curable resin and a photoradical polymerization initiator, and the photoradical polymerization initiator contains a compound represented by the following formula (1-1) and / Or a compound represented by the following formula (1-2).

In the formula (1-1), X represents an alkyl group with 1 to 8 carbon atoms, or a 2-cyclopentylethyl group in which at least one hydrogen of the cyclopentyl ring can be substituted by a methyl group or an ethyl group, and R represents a methyl group Or ethyl.

In formula (1-2), Y represents an alkyl group with 2 to 8 carbon atoms, or a 2-cyclopentylethyl group in which at least one hydrogen of the cyclopentyl ring can be substituted by a methyl group or an ethyl group, and R represents a methyl group Or ethyl.

Hereinafter, the present invention will be described in detail.

The inventors of the present invention found that, surprisingly, by blending a compound having a specific structure as a photoradical polymerization initiator, a sealing compound for liquid crystal display elements that has excellent photocurability and can suppress liquid crystal contamination can be obtained. Thus completed the present invention.

The sealing compound for liquid crystal display elements of this invention contains an optical radical polymerization initiator. The above-mentioned photoradical polymerization initiator contains the compound represented by the above formula (1-1) and/or the compound represented by the above formula (1-2) (hereinafter, also referred to as "the photoradical polymerization initiator of the present invention" ). By containing the photoradical polymerization initiator of the present invention, the sealing compound for liquid crystal display elements of the present invention is highly sensitive, excellent in photocuring properties (especially curability of light-shielding parts), and capable of suppressing liquid crystal contamination.

The sealing compound for liquid crystal display elements of the present invention preferably contains a compound represented by the following formula (2) and/or a compound represented by the following formula (3) as the photoradical polymerization initiator of the present invention, and more preferably contains The compound represented by the following formula (2) serves as the photoradical polymerization initiator of the present invention.

Among the photoradical polymerization initiators of the present invention, commercially available products include, for example, PBG-314, PBG-304 (all manufactured by Changzhou Qiangli Electronic New Materials Co., Ltd.).

Regarding the content of the photoradical polymerization initiator of the present invention, relative to 100 parts by weight of the curable resin, the preferred lower limit is 0.2 parts by weight, and the preferred upper limit is 8 parts by weight. When the content of the radical photopolymerization initiator of the present invention is 0.2 parts by weight or more, the obtained sealing compound for liquid crystal display elements is more excellent in photocurability. By the content of the photo-radical polymerization initiator of the present invention When it is 8 parts by weight or less, the obtained sealing compound for liquid crystal display elements is more excellent in adhesiveness and the effect of suppressing liquid crystal contamination. The lower limit of the content of the photoradical polymerization initiator of the present invention is more preferably 0.5 parts by weight, and the upper limit is more preferably 5 parts by weight.

In addition, the preferred lower limit of the content of the radical photopolymerization initiator of the present invention in 100 parts by weight of the sealing compound for liquid crystal display elements of the present invention is 0.1 part by weight, and the preferred upper limit is 5 parts by weight. When the content of the photoradical polymerization initiator of the present invention is 0.1 parts by weight or more, the obtained sealing compound for liquid crystal display elements is more excellent in photocurability. When the photoradical polymerization initiator of the present invention is 5 parts by weight or less, the obtained sealing compound for liquid crystal display elements is more excellent in adhesiveness and the effect of suppressing liquid crystal contamination. The lower limit of the content of the photo-radical polymerization initiator of the present invention is more preferably 0.3 parts by weight, the upper limit is more preferably 3 parts by weight, the lower limit is still more preferably 0.5 parts by weight, and the upper limit is more preferably 1 part by weight.

The sealing compound for liquid crystal display elements of this invention contains a curable resin.

The curable resin preferably contains a (meth)acrylic compound.

As the above-mentioned (meth)acrylic compound, for example, a (meth)acrylate compound obtained by reacting a compound having a hydroxyl group with (meth)acrylic acid, and a (meth)acrylic acid compound obtained by reacting (meth)acrylic acid with epoxy Epoxy (meth)acrylate obtained by reacting a compound, amine (meth)acrylate obtained by reacting a (meth)acrylic acid derivative having a hydroxyl group with an isocyanate compound, etc. Among them, epoxy (meth)acrylate is preferred. Moreover, in terms of the level of reactivity, the above-mentioned (meth)acrylic compound is preferably one having two or more (meth)acrylic groups in the molecule.

Furthermore, in this specification, the above-mentioned "(meth)acrylic acid" means acrylic acid or methacrylic acid, and the above-mentioned "(meth)acrylic compound" means having an acrylic group or a methacrylic acid group (hereinafter, also one Also known as "(meth)acryloyl") compounds. In addition, the above-mentioned "(meth)acrylate" means Acrylate or methacrylate. Furthermore, the above-mentioned "epoxy (meth)acrylate" means a compound obtained by reacting all epoxy groups in an epoxy compound with (meth)acrylic acid.

Among the above-mentioned (meth)acrylate compounds, monofunctional ones include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and normal (meth)acrylate. Butyl ester, isobutyl (meth)acrylate, tertiary butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate Esters, isononyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, isomyristyl (meth)acrylate, stearyl (meth)acrylate, (meth) ) 2-hydroxyethyl 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-ethoxy (meth)acrylate Ethyl ester, 2-butoxyethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, methoxyethylene glycol (meth)acrylate, methoxypolyethylene glycol (Meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, ethyl carbitol (Meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, (meth)acrylate 1H, 1H, 5H-octafluoropentyl ester, imine (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, 2-(meth)acrylic acid Ethyl succinic acid, 2-(meth)acryloyloxyethyl hexahydrophthalic acid, 2-hydroxypropyl phthalic acid 2-(meth)acryloyloxyethyl, phosphoric acid 2- (Meth)acryloxyethyl, glycidyl (meth)acrylate, etc.

In addition, among the above-mentioned (meth)acrylate compounds, examples of bifunctional ones include 1,3-butanediol di(meth)acrylate and 1,4-butanediol di(meth)acrylic acid Esters, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate Base) acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylic acid Ester, 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 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, dimethylol dicyclopentadienyl di(meth)acrylate, ethylene oxide modified isocyanuric acid Base) acrylate, 2-hydroxy-3-(meth)acryloxypropyl (meth)acrylate, carbonate diol di(meth)acrylate, polyether diol di(meth)acrylic acid Ester, polyesterdiol di(meth)acrylate, polycaprolactonediol di(meth)acrylate, polybutadienediol di(meth)acrylate, etc.

In addition, among the above-mentioned (meth)acrylate compounds, examples of tri- or higher-functionality include trimethylolpropane tri(meth)acrylate, and ethylene oxide-added trimethylolpropane tri( Meth) acrylate, propylene oxide addition trimethylolpropane tri(meth)acrylate, caprolactone modified trimethylolpropane tri(meth)acrylate, ethylene oxide addition isotri Polycyanate tri(meth)acrylate, glycerol tri(meth)acrylate, propylene oxide addition glycerol tri(meth)acrylate, neopentylerythritol tri(meth)acrylate, phosphoric acid tri(meth)acrylate Base) propylene oxyethyl, di-trimethylolpropane tetra (meth) acrylate, neopentyl erythritol tetra (meth) acrylate, dineo pentaerythritol penta (meth) acrylate, two Neopentyl erythritol hexa (meth) acrylate and so on.

As said epoxy (meth)acrylate, the thing obtained by reacting an epoxy compound and (meth)acrylic acid in the presence of a basic catalyst according to a common method, etc. are mentioned, for example.

As the epoxy compound used as a raw material for synthesizing the epoxy (meth)acrylate, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type Epoxy resin, 2,2'-diallyl bisphenol A epoxy resin, hydrogenated bisphenol epoxy resin, propylene oxide addition bisphenol A epoxy resin, resorcinol epoxy resin , Biphenyl epoxy resin, sulfide epoxy resin, diphenyl ether epoxy resin, dicyclopentadiene epoxy resin, naphthalene epoxy resin, phenol novolac epoxy resin, o-cresol Novolak type epoxy resin, dicyclopentadiene novolak type epoxy resin, biphenol novolak type epoxy resin, naphthol novolak type epoxy resin, glycidamine type epoxy resin, alkyl polyol type Epoxy resin, rubber modified epoxy resin, glycidyl ester compound, etc.

Among the above-mentioned bisphenol A epoxy resins, as commercially available products, for example, jER828EL, jER1004 (all manufactured by Mitsubishi Chemical Corporation), EPICLON 850CRP (manufactured by DIC Corporation), and the like can be cited.

Among the above-mentioned bisphenol F-type epoxy resins, as commercially available ones, for example, jER806, jER4004 (all manufactured by Mitsubishi Chemical Co., Ltd.) can be cited.

Among the above-mentioned bisphenol S-type epoxy resins, as commercially available products, for example, EPICLON EXA1514 (manufactured by DIC Corporation) and the like can be cited.

Among the above-mentioned 2,2'-diallylbisphenol A epoxy resins, as a commercially available product, for example, RE-810NM (manufactured by Nippon Kayaku Co., Ltd.) and the like can be cited.

Among the above-mentioned hydrogenated bisphenol type epoxy resins, as a commercially available product, for example, EPICLON EXA7015 (manufactured by DIC Corporation) and the like can be cited.

Among the above-mentioned propylene oxide-added bisphenol A epoxy resins, as commercially available products, for example, EP-4000S (manufactured by ADEKA Corporation) and the like can be cited.

Among the above resorcinol-type epoxy resins, as a commercially available product, for example, EX-201 (manufactured by Nagase chemteX) and the like can be cited.

Among the above-mentioned biphenyl type epoxy resins, as a commercially available product, for example, jER YX-4000H (manufactured by Mitsubishi Chemical Corporation) and the like can be cited.

Among the above-mentioned sulfide-type epoxy resins, examples of commercially available products include YSLV-50TE (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.).

Among the above-mentioned diphenyl ether type epoxy resins, as a commercially available product, for example, YSLV-80DE (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) and the like can be cited.

Among the above-mentioned dicyclopentadiene type epoxy resins, as a commercially available product, for example, EP-4088S (manufactured by ADEKA Corporation) and the like can be cited.

Among the above-mentioned naphthalene-type epoxy resins, as commercially available products, for example, EPICLON HP4032, EPICLON EXA-4700 (all manufactured by DIC Corporation), and the like can be cited.

Among the above-mentioned phenol novolak-type epoxy resins, as a commercially available product, for example, EPICLON N-770 (manufactured by DIC Corporation) and the like can be cited.

Among the above-mentioned ortho-cresol novolak type epoxy resins, as commercially available products, for example, EPICLON N-670-EXP-S (manufactured by DIC Corporation) and the like can be cited.

Among the above-mentioned dicyclopentadiene novolak-type epoxy resins, as a commercially available product, for example, EPICLON HP7200 (manufactured by DIC Corporation) and the like can be cited.

Among the above-mentioned biphenol novolac type epoxy resins, as a commercially available product, for example, NC-3000P (manufactured by Nippon Kayaku Co., Ltd.) and the like can be cited.

Among the above-mentioned naphthol novolac type epoxy resins, as a commercially available product, for example, ESN-165S (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) and the like can be cited.

Among the above-mentioned glycidyl amine type epoxy resins, as commercially available products, for example, jER630 (manufactured by Mitsubishi Chemical Corporation), EPICLON 430 (manufactured by DIC Corporation), TETRAD-X (Mitsubishi Gas Chemical company manufacturing) etc.

Among the above-mentioned alkyl polyol type epoxy resins, as commercially available products, for example, ZX-1542 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), EPICLON 726 (manufactured by DIC Corporation), and Epolight 80MFA (manufactured by Kyoeisha Chemical Co., Ltd.) ), DENACOL EX-611 (manufactured by Nagase chemteX), etc.

Among the above-mentioned rubber-modified epoxy resins, as commercially available products, for example, YR-450, YR-207 (all manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), Epolead PB (manufactured by Daicel), and the like can be cited.

Among the above-mentioned glycidyl ester compounds, as a commercially available product, for example, DENACOL EX-147 (manufactured by Nagase chemteX) and the like can be cited.

Among the above epoxy compounds, other commercially available products include, for example, YDC-1312, YSLV-80XY, YSLV-90CR (all manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd.), XAC4151 (manufactured by Asahi Kasei Corporation), jER1031, jER1032 (All are manufactured by Mitsubishi Chemical Corporation), EXA-7120 (manufactured by DIC Corporation), TEPIC (manufactured by Nissan Chemical Corporation).

Among the above-mentioned epoxy (meth)acrylates, as commercially available products, for example, EBECRYL860, EBECRYL3200, EBECRYL3201, EBECRYL3412, EBECRYL3600, EBECRYL3700, EBECRYL3701, EBECRYL3702, EBECRYL3703, EBECRYL3800, EBECDaRYL6040, EBECDaRYL6040, EBxDa Manufactured by the company), EA-1010, EA-1020, EA-5323, EA-5520, EA-CHD, EMA-1020 (all manufactured by Shin Nakamura Chemical Industry Co., Ltd.), 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 ( All are manufactured by Kyoeisha Chemical Co., Ltd.), DENACOL Acrylic DA-141, DENACOL Acrylic DA-314, DENACOL Acrylic DA-911 (all made by Nagase ChemteX) Made) and so on.

As a (meth)acrylic acid amine ester obtained by reacting a (meth)acrylic acid derivative having a hydroxyl group with the above-mentioned isocyanate compound, for example, it can be made to have a hydroxyl group in the presence of a catalyst amount of a tin-based compound It is obtained by reacting 2 equivalents of the (meth)acrylic acid derivative with 1 equivalent of an isocyanate compound having 2 isocyanate groups.

Examples of the isocyanate compound used as the raw material of the above (meth)acrylate amine ester 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, norbornane diisocyanate, toluidine diisocyanate , Xylylene diisocyanate (XDI), hydrogenated XDI, lysine diisocyanate, triphenylmethane triisocyanate, three (isocyanate phenyl) phosphorothioate, tetramethyl xylylene diisocyanate, 1, 6,11-Undecane triisocyanate, etc.

In addition, as the isocyanate compound used as the raw material of the above-mentioned (meth)acrylate amine ester, for example, it is also possible to use: ethylene glycol, propylene glycol, glycerin, sorbitol, trimethylolpropane, carbonate diol, polyether two A chain-extended isocyanate compound obtained by the reaction of polyols, polyester diols, polycaprolactone diols, and other polyols with excess isocyanate compounds.

Examples of the (meth)acrylic acid derivative having a hydroxyl group used as the raw material of the above-mentioned (meth)acrylate amine ester include: 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, Hydroxyalkyl (meth)acrylates such as 2-hydroxybutyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate, or ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butane Mono(meth)acrylates of diols such as diol, 1,4-butanediol, polyethylene glycol, or mono(meth)acrylates of triols such as trimethylolethane, trimethylolpropane, and glycerol Meth)acrylate or di(meth)acrylate, or bisphenol A type Epoxy (meth)acrylate such as epoxy acrylate, etc.

Among the above (meth)acrylic acid amine esters, as commercially available products, for example, M-1100, M-1200, M-1210, M-1600 (all manufactured by Toagosei Co., Ltd.), EBECRYL210, EBECRYL220, EBECRYL230, EBECRYL270, EBECRYL1290, EBECRYL2220, EBECRYL4827, EBECRYL4842, EBECRYL4858, EBECRYL5129, EBECRYL6700, EBECRYL8402, EBECRYL8803, EBECRYL8804, EBECRYL8807, EBECRYL-TP, Artresin UN-330, Artresin UN-330, Artresin SH Artresin UN-1255, Artresin UN-3320HB, Artresin UN-7100, Artresin UN-9000A, Artresin UN-9000H (all manufactured by Nejo Kogyo), 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 (all manufactured by Shinnakamura Chemical Industry Co., Ltd.) , AH-600, AI-600, AT-600, UA-101I, UA-101T, UA-306H, UA-306I, UA-306T (all manufactured by Kyoeisha Chemical Company), etc.

In order to improve the adhesiveness of the obtained sealing compound for liquid crystal display elements, it is preferable that the said curable resin contains an epoxy compound further. As said epoxy compound, the epoxy compound used as a raw material for synthesizing the said epoxy (meth)acrylate, or a partially (meth)acrylic modified epoxy resin etc. are mentioned, for example.

Furthermore, in this specification, the above-mentioned partial (meth)acrylic modified epoxy resin means a compound having at least one epoxy group and (meth)acrylic group in one molecule, for example, It is obtained by reacting one part of epoxy groups of two or more epoxy compounds with (meth)acrylic acid.

When the sealing compound for liquid crystal display elements of the present invention contains the (meth)acrylic compound and the epoxy compound, it is preferable that the ratio of the (meth)acryloyl group to the epoxy group is 30:70 to 95 : Method 5 blends the above-mentioned (meth)acrylic compound and the above-mentioned epoxy compound. When the ratio of the (meth)acryloyl group is 30% or more, the obtained sealing compound for liquid crystal display elements is more excellent in the effect of suppressing liquid crystal contamination. When the ratio of the (meth)acryloyl group is 95% or less, the obtained sealing compound for liquid crystal display elements is more excellent in adhesiveness.

The curable resin is preferably a unit having hydrogen bonding properties such as -OH group, -NH- group, -NH ₂ group, etc., in terms of suppressing liquid crystal contamination.

The sealing compound for liquid crystal display elements of this invention may contain a thermal radical polymerization initiator.

Examples of the thermal radical polymerization initiator include those composed of azo compounds, organic peroxides, and the like. Among them, a starter composed of a polymer azo compound (hereinafter, also referred to as a "polymer azo starter") is preferred.

Furthermore, in this specification, the so-called polymer azo initiator means that it has an azo group and generates a radical which can harden the (meth)acryloyl group by heat. The number average molecular weight is 300 or more The compound.

The preferred lower limit of the number average molecular weight of the polymer azo initiator is 1,000, and the preferred upper limit is 300,000. When the number average molecular weight of the above-mentioned polymer azo initiator is within this range, it is possible to prevent adverse effects on the liquid crystal, and to mix into the curable resin more easily. The lower limit of the number average molecular weight of the polymer azo initiator is more preferably 5,000, the upper limit is more preferably 100,000, the lower limit is more preferably 10,000, and the upper limit is more preferably 90,000.

Furthermore, in this specification, the above-mentioned number average molecular weight is based on gel permeation chromatography (GPC) The value obtained by the measurement and conversion of polystyrene. As a column for measuring the number average molecular weight in terms of polystyrene by GPC, for example, Shodex LF-804 (manufactured by Showa Denko), etc. can be cited.

Examples of the above-mentioned polymer azo initiator include those having a structure in which a plurality of units such as polyalkylene oxide or polydimethylsiloxane are bonded via an azo group.

As a polymer azo initiator having a structure in which a plurality of units such as polyalkylene oxide are bonded via the above-mentioned azo group, one having a polyethylene oxide structure is preferred. As such a polymer azo initiator, for example, a condensation polymer of 4,4'-azobis(4-cyanovaleric acid) and polyalkylene glycol, or 4,4'-azo The condensation polymer of bis(4-cyanovaleric acid) and polydimethylsiloxane having a terminal amine group, etc., specifically, for example, VPE-0201, VPE-0401, VPE-0601, VPS-0501, VPS-1001 (all manufactured by Wako Pure Chemical Industries, Ltd.), etc.

In addition, examples of azo compounds that are not polymers include V-65 and V-501 (all manufactured by Wako Pure Chemical Industries, Ltd.).

As said organic peroxide, for example, ketone peroxide, peroxyketal, hydrogen peroxide, dialkyl peroxide, peroxyester, diacyl peroxide, peroxydicarbonate, etc. are mentioned.

Regarding the content of the thermal radical polymerization initiator, with respect to 100 parts by weight of the curable resin, the lower limit is preferably 0.05 parts by weight, and the upper limit is preferably 10 parts by weight. When the content of the thermal radical polymerization initiator is within this range, the occurrence of liquid crystal contamination caused by the unreacted radical polymerization initiator is suppressed, and the obtained sealing compound for liquid crystal display elements becomes curable The better. The lower limit of the content of the thermal radical polymerization initiator is more preferably 0.1 parts by weight, and the upper limit is more preferably 5 parts by weight.

The sealing compound for liquid crystal display elements of the present invention preferably contains a thermosetting agent. As said thermosetting agent, organic acid hydrazine, imidazole derivatives, amine compounds, polyphenol compounds, acid anhydrides, etc. are mentioned, for example. Among them, the organic acid hydrazine is preferably used.

As said organic acid hydrazine, dihydrazine sebacate, dihydrazine isophthalate, dihydrazine adipic acid, dihydrazine malonate, etc. are mentioned, for example.

Among the above-mentioned organic acid hydrazine, as commercially available products, for example, SDH, ADH (all manufactured by Otsuka Chemical Co., Ltd.), Amicure VDH, Amicure VDH-J, Amicure UDH, and Amicure UDH-J (all are Ajinomoto Fine- Techno Corporation) and so on.

Regarding the content of the thermosetting agent, with respect to 100 parts by weight of the curable resin, the lower limit is preferably 1 part by weight, and the upper limit is preferably 50 parts by weight. When the content of the thermosetting agent is 1 part by weight or more, the obtained sealing compound for liquid crystal display elements has more excellent thermosetting properties. When the content of the above-mentioned thermosetting agent is 50 parts by weight or less, the viscosity of the obtained sealant does not become too high, and the coating property is more excellent. The more preferable upper limit of the content of the thermal hardening agent is 30 parts by weight.

In order to increase the viscosity, increase the adhesiveness due to the stress dispersion effect, improve the linear expansion rate, and increase the moisture resistance of the cured product, the sealing compound for liquid crystal display elements of the present invention preferably contains a filler.

Examples of the above-mentioned filler include: silica, talc, glass beads, asbestos, gypsum, diatomaceous earth, bentonite, bentonite, montmorillonite, sericite, activated clay, alumina, zinc oxide, Inorganic fillers such as iron oxide, magnesium oxide, tin oxide, titanium oxide, calcium carbonate, magnesium carbonate, magnesium hydroxide, aluminum hydroxide, aluminum nitride, silicon nitride, barium sulfate, calcium silicate, etc., or polyester particles, Polyurethane (polyurethane) particles, vinyl polymer particles Organic fillers such as particles, acrylic polymer particles, etc. These fillers may be used alone, or two or more of them may be used in combination.

The lower limit of the content of the filler in 100 parts by weight of the sealing compound for liquid crystal display elements of the present invention is preferably 10 parts by weight, and the upper limit is preferably 70 parts by weight. When the content of the filler is 10 parts by weight or more, the effect of improving adhesiveness and the like is more excellent. When the content of the filler is 70 parts by weight or less, the viscosity of the obtained sealing compound for liquid crystal display elements does not become too high, and it becomes more excellent in coatability. The lower limit of the filler content is more preferably 20 parts by weight, and the upper limit is more preferably 60 parts by weight.

It is preferable that the sealing compound for liquid crystal display elements of this invention contains a silane coupling agent. The above-mentioned silane coupling agent mainly has a function as an adhesive auxiliary agent for bonding a sealant to a substrate, etc. well.

As the above-mentioned silane coupling agent, it is excellent in the effect of improving the adhesion with the substrate, etc., and can suppress the outflow of the curable resin into the liquid crystal by chemical bonding with the curable resin, for example, 3- Aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-isocyanatopropyltrimethoxysilane, etc. These silane coupling agents may be used alone or in combination of two or more kinds.

The lower limit of the content of the silane coupling agent in 100 parts by weight of the sealing compound for liquid crystal display elements of the present invention is preferably 0.1 parts by weight, and the upper limit is preferably 10 parts by weight. When the content of the silane coupling agent is within this range, the effect of suppressing the occurrence of liquid crystal contamination and improving adhesiveness is more excellent. The lower limit of the content of the silane coupling agent is more preferably 0.3 parts by weight, and the upper limit is more preferably 5 parts by weight.

The sealing compound for liquid crystal display elements of this invention may contain a light-shielding agent. By containing The said light-shielding agent, the sealing compound for liquid crystal display elements of this invention can be used suitably as a light-shielding sealing compound.

Examples of the light-shielding agent include iron oxide, titanium black, aniline black, cyanine black, fullerene, carbon black, and resin-coated carbon black. Among them, titanium black is preferred.

The above-mentioned titanium black is a substance with a higher transmittance in the vicinity of the ultraviolet range, especially light with a wavelength of 370 to 450 nm, compared to the average transmittance of light with a wavelength of 300 to 800 nm. That is, the above-mentioned titanium black is a light-shielding agent having the following properties: it imparts light-shielding properties to the sealing compound for liquid crystal display elements of the present invention by sufficiently shielding light of a wavelength in the visible light range, and transmits light of a wavelength near the ultraviolet range . As the light-shielding agent contained in the sealing compound for liquid crystal display elements of the present invention, a substance with high insulation is preferable, and as a light-shielding agent with high insulation, titanium black is also preferable.

The above-mentioned titanium black exhibits sufficient effects even if it is not surface-treated, but it can also be treated with organic ingredients such as coupling agents, or the surface is treated with silicon oxide, titanium oxide, germanium oxide, aluminum oxide, zirconium oxide, Surface-treated titanium black coated with inorganic components such as magnesium oxide. Among them, those treated with organic components are preferred in terms of further improving insulation.

In addition, the liquid crystal display element manufactured using the sealant for liquid crystal display elements of the present invention containing the titanium black as a light-shielding agent has sufficient light-shielding properties, so there is no light leakage and a high contrast ratio, which can achieve Liquid crystal display element with excellent image display quality.

Among the above-mentioned titanium blacks, commercially available products include, for example, 12S, 13M, 13M-C, 13R-N, and 14M-C (all manufactured by Mitsubishi Materials Corporation), Tilack D (manufactured by Ako Chemical Co., Ltd.), etc. .

The preferred lower limit of the specific surface area of the titanium black is 13 m ² /g, the preferred upper limit is 30 m ² /g, the more preferred lower limit is 15 m ² /g, and the more preferred upper limit is 25 m ² /g.

In addition, the preferred lower limit of the volume resistance of the titanium black is 0.5Ω‧cm, the preferred upper limit is 3Ω‧cm, the more preferred lower limit is 1Ω‧cm, and the more preferred upper limit is 2.5Ω‧cm.

The initial particle size of the light-shielding agent is not particularly limited as long as it is less than the distance between the substrates of the liquid crystal display element, and the preferred lower limit is 1 nm, and the preferred upper limit is 5000 nm. When the initial particle size of the light-shielding agent is within this range, it is possible to make it more excellent in light-shielding properties without deteriorating the coatability and the like of the obtained sealing compound for liquid crystal display elements. The lower limit of the initial particle size of the sunscreen is more preferably 5 nm, the upper limit is more preferably 200 nm, the lower limit is still more preferably 10 nm, and the upper limit is more preferably 100 nm.

In addition, the initial particle size of the sunscreen can be measured by dispersing the sunscreen in a solvent (water, organic solvent, etc.) using NICOMP 380ZLS (manufactured by PARTICLE SIZING SYSTEMS).

The lower limit of the content of the light-shielding agent in 100 parts by weight of the sealing compound for liquid crystal display elements of the present invention is preferably 5 parts by weight, and the upper limit is preferably 80 parts by weight. When the content of the light-shielding agent is within this range, the obtained sealing compound for a liquid crystal display element is more excellent in light-shielding properties while maintaining excellent display properties, adhesiveness, and strength after curing. The lower limit of the content of the sunscreen is more preferably 10 parts by weight, the upper limit is more preferably 70 parts by weight, the lower limit is still more preferably 30 parts by weight, and the upper limit is more preferably 60 parts by weight.

As a method of manufacturing the sealant for liquid crystal display elements of the present invention, for example, the curable resin can be combined with a mixer such as a homogenizer, homomixer, universal mixer, planetary mixer, kneader, and three-roll mill. , The method for mixing the photo-radical polymerization initiator of the present invention, and optionally the silane coupling agent and other additives.

For the sealing compound for liquid crystal display elements of the present invention, E-type viscosity is used The lower limit of the viscosity measured under the conditions of 25℃ and 1rpm is 100,000 mPa‧s, and the upper limit is 600,000 mPa‧s. When the said viscosity is in this range, the obtained sealing compound for liquid crystal display elements will be excellent in coatability. The better lower limit of the above viscosity is 150,000 mPa‧s, and the more preferable upper limit is 450,000 mPa‧s.

By blending conductive fine particles in the sealing compound for liquid crystal display elements of the present invention, a vertical conduction material can be produced. In addition, such a top and bottom conduction material containing the sealing compound for liquid crystal display elements of the present invention and conductive fine particles is also one of the present invention.

As the conductive fine particles, metal balls, those having a conductive metal layer formed on the surface of resin fine particles, or the like can be used. Among them, those with a conductive metal layer formed on the surface of the resin particles are preferred because of the excellent elasticity of the resin particles and can be electrically connected without damaging the transparent substrate or the like.

In addition, a liquid crystal display element using the sealing compound for liquid crystal display elements of the present invention or the top and bottom conduction material of the present invention is also one of the present invention.

As a method of manufacturing the liquid crystal display element of the present invention, a liquid crystal drop processing method is preferably used. Specifically, for example, a method including the following steps: on one of two substrates, such as a glass substrate with electrodes such as an ITO film or a polyethylene terephthalate substrate, by screen printing, a dispenser The step of applying the sealant for liquid crystal display elements of the present invention, etc., to form a frame-shaped sealing pattern; in the uncured state of the sealant for liquid crystal display elements of the present invention, droplets of liquid crystal are dropped The step of applying to the frame of the sealing pattern of the substrate and superimposing another substrate under vacuum; and the step of irradiating the part of the sealing pattern such as the sealant for liquid crystal display elements of the present invention with light such as ultraviolet light to temporarily harden the sealant; and The step of heating the temporarily hardened sealant to formally harden it.

According to the present invention, it is possible to provide a sealing compound for a liquid crystal display element that is excellent in photocurability and can suppress liquid crystal contamination. In addition, according to the present invention, it is possible to provide an upper and lower conduction material and a liquid crystal display element using the sealing compound for liquid crystal display elements.

Hereinafter, the present invention will be described in further detail with examples, but the present invention is not limited to these examples.

(Examples 1 to 7, Comparative Examples 1 to 4)

According to the blending ratio described in Table 1, the materials were mixed using a planetary mixer (manufactured by Thinky, "Defoaming Stir Taro"), and then mixed using a three-roll mill to prepare Examples 1 to 7. Each of the sealing compounds for liquid crystal display elements of Comparative Examples 1 to 4.

<evaluation>

The following evaluation was performed about each sealing compound for liquid crystal display elements obtained in an Example and a comparative example. The results are shown in Table 1.

(Light hardening)

1 part by weight of spacer particles (manufactured by Sekisui Chemical Industry Co., Ltd., "Micropearl SI-H050") was dispersed in 100 parts by weight of each liquid crystal display element sealing compound obtained in the examples and comparative examples, and the obtained was applied to On the glass substrate, a glass substrate of the same size was stacked on the substrate, and then a metal halide lamp was used to irradiate light of 100 mW/cm ² for 10 seconds to prepare a photocurable test piece. The light irradiation was performed in two modes: the case without a cut-off filter and the case with a cut-off filter below 380nm, and three test pieces were made for each of the two cases. An infrared spectrometer (manufactured by BIORAD, "FTS3000") was used to measure the amount of change before and after light irradiation derived from the peak of the (meth)acrylic acid group to evaluate the photocurability. The case where the peak derived from (meth)acrylic acid group is reduced by more than 95% after light irradiation is regarded as "◎", and the peak derived from (meth)acrylic acid group after light irradiation is reduced to 80% or more without When it reaches 95%, it is regarded as "○", and when the peak derived from (meth)acrylic acid group is reduced to 70% or more and less than 80% after light irradiation, it is regarded as "△". If the decrease from the peak of the (meth)acrylic acid group is less than 70%, it is regarded as "×", and the photocurability is evaluated.

Furthermore, the amount of change before and after light irradiation derived from the peak of the (meth)acrylic acid group is the average value obtained from 3 test pieces.

(Liquid crystal contamination)

After dispersing 1 part by weight of spacer particles (manufactured by Sekisui Chemical Industry Co., Ltd., "Micropearl SI-H050") in 100 parts by weight of each liquid crystal display element sealing compound obtained in the examples and comparative examples, the tape was applied to 2 sheets The rubbed alignment film and one of the transparent electrode substrates are coated with a dispenser in a frame shape with a line width of 1 mm.

Then, small drops of liquid crystal (manufactured by Chisso, "JC-5004LA") were applied to the entire surface of the sealant frame of the substrate with transparent electrodes, and another substrate with transparent electrodes was immediately pasted, using metal The halide lamp irradiated the sealant portion with light of 100 mW/cm ² for 10 seconds to harden the sealant, and further heated at 120° C. for 1 hour to obtain a liquid crystal display element. The light irradiation was performed in two modes: the case without a cut-off filter and the case with a cut-off filter below 380nm, and three liquid crystal display elements were produced for each of the two cases.

With regard to the obtained liquid crystal display element, the liquid crystal contamination in the vicinity of the sealant after applying a voltage at 60°C for 1000 hours was confirmed visually.

Liquid crystal contamination is judged based on the chromatic aberration of the three liquid crystal display elements. According to the degree of the chromatic aberration, the case where all the liquid crystal display elements are completely free of color aberration is regarded as "◎", and the case where there is a slight chromatic aberration in at least one liquid crystal display element If it is "○", it will be regarded as "△" if there is less chromatic aberration in at least one liquid crystal display element, and it will be "×" if there is more chromatic aberration in at least one liquid crystal display element, which will contaminate the liquid crystal. Evaluation.

Furthermore, the liquid crystal display elements evaluated as "◎" and "○" are at the level of practically no problem at all.

[Possibility of industrial use]

According to the present invention, it is possible to provide a sealing compound for a liquid crystal display element that is excellent in photocurability and can suppress liquid crystal contamination. In addition, according to the present invention, it is possible to provide an upper and lower conduction material and a liquid crystal display element using the sealing compound for liquid crystal display elements.

Claims (5)

A sealing compound for liquid crystal display elements, which contains a curable resin and a photo-radical polymerization initiator, and is characterized in that the photo-radical polymerization initiator contains a compound represented by the following formula (1-1) And/or a compound represented by the following formula (1-2),

In the formula (1-1), X represents an alkyl group with 1 to 8 carbon atoms, or a 2-cyclopentylethyl group in which at least one hydrogen of the cyclopentyl ring can be substituted by a methyl group or an ethyl group, and R represents a methyl group Or ethyl, in formula (1-2), Y represents 2-cyclopentylethyl in which at least one hydrogen of the cyclopentyl ring can be substituted by methyl or ethyl, and R represents methyl or ethyl. For example, the sealing compound for liquid crystal display elements of the first item of the scope of patent application, wherein the photoradical polymerization initiator contains a compound represented by the following formula (2),

For example, the sealing compound for liquid crystal display elements of the first or second item of the scope of patent application contains a light-shielding agent. An up-and-down conduction material, which contains the sealing compound for liquid crystal display elements of the first, second or third patent application range and conductive particles. A liquid crystal display element, which is formed by using the sealant for liquid crystal display elements of the 1, 2 or 3 patent application scope or the upper and lower conduction materials of the 4 patent application scope.