TW201739831A - Sealing agent for liquid crystal display elements, vertically conducting material and liquid crystal display element - Google Patents

Abstract

One purpose of the present invention is to provide a sealing agent for liquid crystal display elements, which is capable of suppressing contamination of liquid crystals, while exhibiting excellent curability in a light-blocked part. Another purpose of the present invention is to provide: a vertically conducting material which is obtained using this sealing agent for liquid crystal display elements; and a liquid crystal display element. A sealing agent for liquid crystal display elements, which contains a curable resin and a radical photopolymerization initiator, and wherein: the curable resin contains a compound having a molecular weight of 100 or more but less than 500 and a compound having a molecular weight of 500-3,000; and the radical photopolymerization initiator is a compound having a carbazole skeleton.

Description

Sealant for liquid crystal display element, upper and lower conductive materials, and liquid crystal display element

The present invention relates to a sealing agent for a liquid crystal display element which is excellent in hardenability of a light-shielding portion and which can suppress liquid crystal contamination. Moreover, the present invention relates to an upper and lower conductive material and a liquid crystal display element using the sealing agent for a liquid crystal display element.

In recent years, as a method of manufacturing a liquid crystal display element such as a liquid crystal display unit, the use of the method of dropping the method as disclosed in Patent Document 1 and Patent Document 2 is known from the viewpoint of shortening the production time and optimizing the amount of liquid crystal. In the liquid crystal dropping method, a photocuring curing curing sealant containing a curable resin, a photopolymerization initiator, and a thermosetting agent is used.

Regarding the dropping method, first, a rectangular sealing pattern is formed by one drop coating on one of the two electrode-attached transparent substrates. Then, a small droplet of liquid crystal is dropped onto the entire surface of the transparent substrate in a state where the sealant is not cured, and the other transparent substrate is immediately superposed, and the sealing portion is irradiated with light such as ultraviolet rays to be temporarily cured. Then, it is heated and solidified at the time of liquid crystal annealing to produce a liquid crystal display element. When the substrate is bonded under reduced pressure, the liquid crystal display element can be manufactured with extremely high efficiency. At present, the dropping method is becoming the mainstream of the method for producing a liquid crystal display element.

In addition, in the modernization of mobile devices including mobile phones and mobile game boards, such as mobile phones and portable game machines, the miniaturization of devices is the subject of most concern. Small as a device The method of the method includes narrow edge of the liquid crystal display unit. For example, the position of the sealing portion is placed under a black matrix (hereinafter also referred to as a narrow edge design).

However, in the narrow edge design, since the sealant is disposed directly under the black matrix, there is a problem that when the dropping method is performed, the light irradiated by the sealant is hardened, and the light does not reach the sealant. Internally, hardening becomes insufficient. If the curing of the sealant is insufficient, the uncured sealant component is eluted into the liquid crystal, and the hardening reaction by the eluted sealant component proceeds in the liquid crystal, thereby causing liquid crystal contamination.

As a method of suppressing liquid crystal contamination, Patent Document 3 discloses a content of a photopolymerization initiator which incorporates a high sensitivity to a sealant. However, if only a high-sensitivity photopolymerization initiator is blended, liquid crystal contamination cannot be sufficiently suppressed in the light-shielding portion.

Patent Document 1: Japanese Patent Laid-Open Publication No. 2001-133794

Patent Document 2: International Publication No. 02/092718

Patent Document 3: International Publication No. 2012/002028

An object of the present invention is to provide a sealing agent for a liquid crystal display element which is excellent in the hardenability of a light-shielding portion and which can suppress liquid crystal contamination. Moreover, an object of the present invention is to provide an upper and lower conductive material and a liquid crystal display element using the sealing agent for a liquid crystal display element.

The present invention relates to a sealant for a liquid crystal display element, comprising a curable resin and light In the radical polymerization initiator, the curable resin contains a compound having a molecular weight of 100 or more and less than 500 and a compound having a molecular weight of 500 to 3,000, and the photoradical polymerization initiator is a compound having a carbazole skeleton.

The invention is described in detail below.

The present inventors have studied a case where a compound having a carbazole skeleton is used as a photopolymerization initiator which is particularly high in sensitivity in order to improve the hardenability of the light-shielding portion of the sealant. However, even when such a photoradical polymerization initiator is used, there is a problem that the light-shielding portion has insufficient curability and liquid crystal contamination is likely to occur. The present inventors have considered that a compound having a carbazole skeleton used as a photoradical polymerization initiator is highly sensitive, but has low solubility in a curable resin, and thus it is not possible to sufficiently improve the shading portion hardenability. Therefore, the present inventors have found that by using not only a compound having a carbazole skeleton as a photoradical polymerization initiator but also a compound having a specific molecular weight and using it as a curable resin, it is possible to obtain an excellent light-shielding property and can be obtained. The present invention has been completed by a sealing agent for a liquid crystal display element which suppresses liquid crystal contamination.

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

The curable resin contains a compound having a molecular weight of 100 or more and less than 500 and a compound having a molecular weight of 500 to 3,000. By using a compound having a molecular weight of 100 or more and less than 500 in combination with a compound having a molecular weight of 500 to 3,000, the compound having a carbazole skeleton as a photoradical polymerization initiator can be sufficiently dissolved. In the sealing agent for liquid crystal display elements of the present invention, the light-shielding portion is excellent in hardenability and can suppress liquid crystal contamination.

In the present specification, the above-mentioned "molecular weight" is a compound having a specific molecular structure and having a molecular weight determined by a structural formula, but a compound having a broad distribution of polymerization degree and a compound having a modified portion are not specific. There are cases where the weight average molecular weight is used. In this manual In the above, the "weight average molecular weight" is a value measured by gel permeation chromatography (GPC) and determined by polystyrene conversion. The column to be used for the measurement of the weight average molecular weight in terms of polystyrene by GPC is, for example, Shodex LF-804 (manufactured by Showa Denko Co., Ltd.).

The curable resin contains a compound having a molecular weight of 100 or more and less than 500.

The compound having a molecular weight of 100 or more and less than 500 is preferably a molecular weight of 300 or more and less than 500 from the viewpoint of solubility of a compound having a carbazole skeleton.

The curable resin preferably contains a (meth)acrylic compound as a compound having a molecular weight of 100 or more and less than 500.

The (meth)acrylic compound may, for example, be a (meth) acrylate compound obtained by reacting (meth)acrylic acid with a compound having a hydroxyl group, by using (meth)acrylic acid and an epoxy compound. An epoxy (meth) acrylate obtained by the reaction, a (meth)acrylic acid urethane obtained by reacting an isocyanate compound with a (meth)acrylic acid derivative having a hydroxyl group, and the like. Among them, epoxy (meth) acrylate is preferred. Moreover, it is preferable that the (meth)acrylic compound has two or more (meth) acrylonitrile groups in one molecule in terms of high reactivity. In the present specification, the above "(meth)acrylic acid" means acrylic acid or methacrylic acid, and the above "(meth)acrylic acid compound" means having an acrylonitrile group or a methacrylic acid group (hereinafter, also referred to as It is a compound of "(meth)acryloyl). Further, the above "(meth) acrylate" means acrylate or methacrylate. Further, the above-mentioned "epoxy (meth) acrylate" means a compound obtained by reacting all of the epoxy groups in the epoxy compound with (meth)acrylic acid.

As a monofunctional one in the above (meth) acrylate compound, for example, it can be listed Methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, (meth)acrylic acid Tributyl ester, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, isodecyl (meth)acrylate, isophthalide (meth)acrylate Ester, lauryl (meth)acrylate, isomyristyl (meth)acrylate, stearyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate , 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, cyclohexyl (meth)acrylate, isodecyl (meth)acrylate, dicyclopentene (meth)acrylate Ester, benzyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, ( 2-phenoxyethyl methacrylate, methoxyethylene glycol (meth) acrylate, phenoxy diethylene glycol (meth) acrylate, tetrahydrofuran methyl (meth) acrylate, ethyl Carbitol (meth) acrylate, (meth) acrylate 2, 2,2-trifluoroethyl ester, 2,2,3,3-tetrafluoropropyl (meth)acrylate, 1H,1H,5H-octafluoropentyl (meth)acrylate, quinone imine (methyl) Acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, 2-(meth)acryloxyethyl succinic acid, 2-(methyl) propylene oxime Oxyethylhexahydrophthalic acid, 2-(methyl)propenyloxyethyl 2-hydroxypropyl phthalate, 2-(meth)acryloxyethyl phosphate, (A) Base) glycidyl acrylate and the like.

Further, examples of the difunctionality in the (meth) acrylate compound include 1,3-butanediol di(meth)acrylate and 1,4-butanediol di(meth)acrylate. 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-nonanediol di(meth)acrylate, ethylene glycol II (Meth) acrylate, diethylene glycol di(meth) acrylate, tetraethylene glycol di(meth) acrylate, 2-n-butyl-2-ethyl-1,3-propanediol di(A) Acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, dimethylol dicyclopentadienyl di(a) Acrylate, ethylene oxide modified isomeric cyanuric acid (Meth) acrylate, 2-hydroxy-3-(meth) propylene methoxy propyl (meth) acrylate, carbonate diol di (meth) acrylate, and the like.

In addition, examples of the trifunctional or higher functional group of the (meth) acrylate compound include trimethylolpropane tri(meth)acrylate and ethylene oxide addition trimethylolpropane tris(methyl). Acrylate, tris(meth)acrylate, pentaerythritol tri(meth)acrylate, tris(meth)acryloxyethyl phosphate, pentaerythritol tetra(meth)acrylate Wait.

The epoxy (meth) acrylate may, for example, be obtained by reacting an epoxy compound with (meth)acrylic acid in the presence of a basic catalyst according to a conventional method.

Examples of the epoxy compound to be used as a raw material for synthesizing the above epoxy (meth) acrylate include bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, and bisphenol E bicyclic ring. Oxypropyl propyl ether, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol E diglycidyl ether, resorcinol diepoxypropyl ether, Benzene-4,4,-diylbis(epoxypropyl ether), 1,6-naphthalenediylbis(epoxypropyl ether), ethylene glycol diepoxypropyl ether, 1,3-propanediol Epoxypropyl ether, 1,4-butanediol diepoxypropyl ether, and the like.

As the above-mentioned (meth)acrylic acid urethane obtained by reacting an isocyanate compound with a (meth)acrylic acid derivative having a hydroxyl group, for example, an isocyanate compound 1 having two isocyanate groups can be used. The equivalent is 2 equivalents of a (meth)acrylic acid derivative having a hydroxyl group, and is obtained by reacting in the presence of a catalyst amount of a tin-based compound.

Examples of the isocyanate compound which is a raw material of the above (meth)acrylic acid urethane include isophorone diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and hexamethylene group. Diisocyanate, trimethylhexamethylene diisocyanate, diphenylmethane-4,4,-diisocyanate (MDI), hydrogenated MDI, 1,5-naphthalene diisocyanate, lower Norbornane diisocyanate, benzidine diisocyanate, benzodimethyl diisocyanate (XDI), hydrogenated XDI, diazonic acid diisocyanate, tetramethyl dimethyl diisocyanate, and the like.

Examples of the (meth)acrylic acid derivative having a hydroxyl group which is a raw material of the above (meth)acrylic acid urethane are 2-hydroxyethyl (meth)acrylate and 2-hydroxyl (meth)acrylate. a hydroxyalkyl (meth)acrylate such as propyl ester, 2-hydroxybutyl (meth)acrylate or 4-hydroxybutyl (meth)acrylate, or ethylene glycol, propylene glycol, 1,3-propanediol, 1, A mono(meth)acrylate of a glycol such as 3-butanediol or 1,4-butanediol.

The curable resin preferably contains an epoxy compound as the compound having a molecular weight of 100 or more and less than 500 from the viewpoint of the adhesiveness and solubility of the compound having a carbazole skeleton.

Examples of the epoxy compound include an epoxy compound or a partial (meth)acrylic modified epoxy resin which is a raw material for synthesizing the above epoxy (meth)acrylate.

In the present specification, the above-mentioned partial (meth)acrylic acid-modified epoxy resin means a compound having one or more epoxy groups and a (meth)acryl fluorenyl group in one molecule, for example, It is obtained by reacting a partial epoxy group of one or more epoxy compounds with (meth)acrylic acid.

The curable resin contains a compound having a molecular weight of 500 to 3,000. The lower limit of the molecular weight of the above compound having a molecular weight of 500 to 3,000 is preferably 600, and the upper limit is preferably 2,500. When the molecular weight of the compound having a molecular weight of 500 to 3,000 is 600 or more, the solubility of the compound having a carbazole skeleton is further improved. When the molecular weight of the compound having a molecular weight of 500 to 3,000 is 2,500 or less, the obtained liquid crystal display element sealing agent is more excellent in low liquid crystal contamination. The lower limit of the molecular weight of the compound having a molecular weight of 500 to 3,000 is preferably 1,000, and more preferably the upper limit is 2,000.

The compound having a molecular weight of 500 to 3,000 is preferably an oligomer compound, more preferably an oligomer compound having a polymerization degree of 3 to 6.

In addition, the compound having a molecular weight of 500 to 3,000 is preferably a polyfunctional compound having a total of two or more epoxy groups and/or (meth) acrylonitrile groups in one molecule, and the crosslinking density is improved and can be further suppressed. In terms of dissolution, a polyfunctional compound having a comb structure such as a novolac type structure is more preferable.

Specific examples of the compound having a molecular weight of 500 to 3,000 include a phenol novolak type epoxy resin, an o-cresol novolak type epoxy resin, a dicyclopentadiene novolac type epoxy resin, and a biphenol. Aldehyde type epoxy resin, naphthol novolac type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, bisphenol S type epoxy resin, 2, 22,-Diallyl bisphenol A type epoxy resin, hydrogenated bisphenol type epoxy resin, propylene oxide addition bisphenol A type epoxy resin, resorcinol type epoxy resin, biphenyl type epoxy Resin, thioether epoxy resin, diphenyl ether epoxy resin, dicyclopentadiene epoxy resin, naphthalene epoxy resin, glycidylamine epoxy resin, alkyl polyol epoxy resin, An oligomeric epoxy resin such as a rubber-modified epoxy resin or an oligomeric epoxy (meth)acrylate obtained by reacting the oligomeric epoxy resin with (meth)acrylic acid Or an oligomeric type (meth)acrylic acid modified epoxy resin or the like. Among them, an oligomeric epoxy (meth) acrylate is preferred.

A preferred lower limit of the content of the compound having a molecular weight of 500 to 3,000 in 100 parts by weight of the compound having a molecular weight of 100 or more and less than 500 and a compound having a molecular weight of 500 to 3,000 is 10 parts by weight, preferably 30 Parts by weight. When the content of the compound having a molecular weight of 500 to 3,000 is within this range, the effect of the light-shielding portion of the sealing agent for a liquid crystal display element and the effect of suppressing liquid crystal contamination are further improved. The above molecular weight is 500~3000 A more preferred lower limit of the compound content is 12 parts by weight, and a more preferred upper limit is 20 parts by weight.

The sealing agent for liquid crystal display elements of this invention contains a photoradical polymerization initiator.

The above photoradical polymerization initiator is a compound having a carbazole skeleton. By using the compound having a carbazole skeleton as the photoradical polymerization initiator, the sealing agent for a liquid crystal display device of the present invention is excellent in the light-shielding property of the light-shielding portion.

A preferred lower limit of the molecular weight of the above compound having a carbazole skeleton is 300, and a preferred upper limit is 1,000. When the molecular weight of the compound having a carbazole skeleton is within this range, the solubility in the curable resin is further improved. A more preferred lower limit of the molecular weight of the above compound having a carbazole skeleton is 400, and a more preferred upper limit is 700.

The compound having a carbazole skeleton is preferably an aromatic ring other than the aromatic ring contained in the carbazole skeleton from the viewpoint of solubility in the curable resin.

In addition, the compound having a carbazole skeleton preferably has a nitrogen atom other than a nitrogen atom contained in the carbazole skeleton, and more preferably has a oxime ester bond, from the viewpoint that the light-shielding portion is more excellent in curability.

The compound having a carbazole skeleton preferably has an absorption coefficient of 50 mL/g at a wavelength of 365 nm measured in acetonitrile in which the compound having the carbazole skeleton is mixed at a concentration of 0.1 mg/mL. More than cm. The absorption coefficient of the compound having the above carbazole skeleton is 50 mL/g. In the case of cm or more, the obtained sealing agent for a liquid crystal display element has more excellent light-shielding property. The absorption coefficient of the above compound having a carbazole skeleton is preferably 100 mL/g. More than cm.

Further, the preferred upper limit of the light absorption coefficient of the compound having a carbazole skeleton is not particularly limited, and the upper limit is substantially 1000 mL/g. Cm.

Specific examples of the compound having a carbazole skeleton include O-ethinyl-1-(6-(2-methylbenzomethyl)-9-ethyl-9H-carbazole-3. -yl)ketone oxime, 3,6-bis-(2-methyl-2- Lolinyl-propenyl)-9-N-octylcarbazole, 3,6-bis(2-methyl-2- Polinylpropenyl)-9-benzimidylcarbazole, 3,6-bis(2-methyl-2-phenylpropanyl)-9-n-butylcarbazole, 3,6-bis ( 2-methyl-2- Polinylpropenyl)-9-n-dodecylcarbazole, 2-(N-n-butyl-3'-carbazolyl)-4,6-bis(trichloromethyl)-symmetric three Wait.

The commercially available one of the compounds having a carbazole skeleton may, for example, be IRGACURE OXE02 (manufactured by BASF Corporation).

The preferred lower limit of the content of the compound having a carbazole skeleton with respect to 100 parts by weight of the curable resin is 0.5 part by weight, and preferably the upper limit is 10 parts by weight. When the content of the compound having a carbazole skeleton is within this range, the obtained sealing agent for a liquid crystal display element is more excellent in the light-shielding property of the light-shielding portion, the weather resistance, the storage stability, and the effect of suppressing liquid crystal contamination. A more preferred lower limit of the content of the above compound having a carbazole skeleton is 1 part by weight, and a more preferred upper limit is 3 parts by weight.

In the sealing agent for a liquid crystal display device of the present invention, in addition to the compound having a carbazole skeleton, another photoradical polymerization initiator may be contained as the photoradical polymerization initiator, but the shading portion is hardenable and suppressed. From the viewpoint of the effect of liquid crystal contamination, it is preferred that no other photoradical polymerization initiator is contained.

The sealant for a liquid crystal display element of the present invention may further contain a sensitizer.

In the sealing agent for a liquid crystal display device of the present invention, the sensitizer is used, and a sealing agent for a liquid crystal display element having excellent light-shielding property can be obtained with higher sensitivity.

The sensitizer is preferably selected from the group consisting of a compound having a benzophenone skeleton, a compound having an anthracene skeleton, and an anthracene skeleton in terms of having a sufficient light absorption band in the ultraviolet-visible light region. a compound having a coumarin skeleton and having 9-oxosulfur At least one compound selected from the group consisting of a skeleton compound and a compound having a phthalocyanine skeleton, more preferably selected from the group consisting of a compound having an anthracene skeleton, a compound having an anthracene skeleton, and having 9-oxosulfuric acid At least one compound of the group consisting of the compounds of the skeleton.

Examples of the compound having a benzophenone skeleton include benzophenone, 2,4-dichlorobenzophenone, and 4,4,-bis(dimethylamino)benzophenone, and 4, 4,-bis(diethylamino)benzophenone and the like.

Examples of the compound having an anthracene skeleton include 9,10-diethoxyanthracene, 9,10-dipropoxyanthracene, and 9,10-dibutoxyanthracene.

Examples of the compound having an anthracene skeleton include 1-methylanthracene, 2-ethylanthracene, 1,4-dihydroxyindole, and 2-(2-hydroxyethoxy)anthracene.

Examples of the compound having a coumarin skeleton include 7-diethylamino-4-methylcoumarin.

As the above, having 9-oxosulfur The compound of the skeleton may, for example, be 2,4-diethyl 9-oxosulfur 2-chloro 9-oxosulfur 4-isopropyl 9-oxosulfur 1-chloro-4-propyl 9-oxosulfur Wait.

Examples of the compound having a phthalocyanine skeleton include phthalocyanine and the like.

Among these sensitizers, 4,4'-bis(dimethylamino)benzophenone and 4,4'-bis(dimethylamino)benzophenone are preferable in terms of particularly excellent light-shielding property of the sealing agent for liquid crystal display elements obtained. At least one of 4,4'-bis(diethylamino)benzophenone.

A preferred lower limit of the content of the sensitizer relative to 100 parts by weight of the photoradical polymerization initiator is 2 parts by weight, preferably 50 parts by weight. By the above sensitizer When the content is in this range, liquid crystal contamination is suppressed, and the obtained sealing agent for a liquid crystal display element has more excellent light-shielding property. A more preferred lower limit of the above sensitizer content is 5 parts by weight, and a more preferred upper limit is 40 parts by weight.

The sealant for a liquid crystal display element of the present invention may further contain a thermal radical polymerization initiator.

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

In the present specification, the polymer azo compound means a compound having an azo group and having a number average molecular weight of 300 or more by heat generation.

A preferred lower limit of the number average molecular weight of the above polymer azo initiator is 1,000, and a preferred upper limit is 300,000. When the number average molecular weight of the above polymer azo initiator is within this range, liquid crystal contamination can be suppressed and easily mixed with the curable resin. The lower limit of the number average molecular weight of the above polymer azo initiator is 5,000, more preferably 100,000, and still more preferably 10,000, and further preferably 90,000.

Further, in the present specification, the above-mentioned number average molecular weight is a value determined by gel permeation chromatography (GPC) and determined by polystyrene conversion. The column for the number average molecular weight in the polystyrene conversion by GPC is, for example, Shodex LF-804 (manufactured by Showa Denko KK).

The polymer azo initiator is, for example, a structure having a plurality of units such as polyalkylene oxide or polydimethyl methoxyoxane bonded via an azo group.

As the above structure having a structure in which a plurality of units such as polyalkylene oxide are bonded via an azo group The molecular azo initiator is preferably one having a polyethylene oxide structure. As such a polymer azo initiator, for example, a polycondensate of 4,4,-azobis(4-cyanovaleric acid) and a polyalkylene glycol, or 4,4,-azo may be mentioned. a polycondensate of bis(4-cyanovaleric acid) and a polydimethyl methoxyalkane having a terminal amino group, and specific examples thereof include VPE-0201, VPE-0401, VPE-0601, and VPS-0501. , VPS-1001 (all manufactured by Wako Pure Chemical Industries, Ltd.) and so on. In addition, examples of the azo compound which is not a polymer include V-65 and V-501 (all manufactured by Wako Pure Chemical Industries, Ltd.).

Examples of the organic peroxide include ketone peroxide, peroxyketal, hydrogen peroxide, dialkyl peroxide, peroxyester, dinonyl peroxide, and peroxydicarbonate.

The lower limit of the content of the above-mentioned thermal radical polymerization initiator is preferably 0.05 parts by weight, and preferably 10 parts by weight, based on 100 parts by weight of the curable resin. When the thermal radical polymerization initiator is in this range, the obtained sealing agent for a liquid crystal display element suppresses liquid crystal contamination, and is more excellent in storage stability or hardenability. A more preferred lower limit of the content of the above thermal radical polymerization initiator is 0.1 part by weight, and a more preferred upper limit is 5 parts by weight.

The sealant for a liquid crystal display element of the present invention may further contain a heat hardener.

Examples of the above-mentioned thermosetting agent include an organic acid hydrazine, an imidazole derivative, an amine compound, a polyphenol compound, and an acid anhydride. Among them, organic acid hydrazine is suitably used.

Examples of the organic acid hydrazine include anthraquinone, diammonium isophthalate, hexamethylene dioxime, and propylene dithoxide.

For example, SDH, ADH (all manufactured by Otsuka Chemical Co., Ltd.), Amicure VDH, Amicure VDH-J, Amicure UDH, and Amicure UDH-J (both are Ajinomoto Fine-Techno). Company manufacturing) and so on.

The content of the above thermal curing agent is 100 parts by weight based on the above curable resin A preferred lower limit is 1 part by weight, and a preferred upper limit is 50 parts by weight. When the content of the above-mentioned heat-hardening agent is in this range, the coating property of the obtained sealing compound for liquid crystal display elements and the like can be deteriorated, and the thermosetting property can be further improved. A more preferable upper limit of the content of the above thermal curing agent is 30 parts by weight.

The sealing agent for a liquid crystal display element of the present invention preferably contains a filler in order to improve the viscosity, improve the adhesion determined by the stress dispersion effect, improve the linear expansion ratio, and further improve the moisture resistance of the cured product.

Examples of the filler include cerium oxide, talc, glass beads, asbestos, gypsum, diatomaceous earth, bentonite, bentonite, montmorillonite, sericite, activated clay, alumina, zinc oxide, iron oxide, and oxidation. Inorganic fillers such as magnesium, tin oxide, titanium oxide, calcium carbonate, magnesium carbonate, magnesium hydroxide, aluminum hydroxide, aluminum nitride, tantalum nitride, barium sulfate, calcium citrate, or polyester microparticles, polyamine An organic filler such as an acid ester microparticle, an ethylene polymer microparticle, or an acrylic polymer microparticle.

A preferred lower limit of the filler content in 100 parts by weight of the sealant for a liquid crystal display device of the present invention is 10 parts by weight, and preferably the upper limit is 70 parts by weight. When the content of the filler is within this range, the effect of improving the adhesion can be further improved without impairing the coatability and the like. A more preferred lower limit of the above filler content is 20 parts by weight, and a more preferred upper limit is 60 parts by weight.

The sealing agent for liquid crystal display elements of the present invention preferably contains a decane coupling agent. The above decane coupling agent mainly functions as a bonding aid for adhering a sealing agent to a substrate or the like well.

The decane coupling agent is excellent in the effect of improving the adhesion to a substrate or the like, and can be used to inhibit the flow of the curable resin into the liquid crystal by chemical bonding with the curable resin. For example, 3-aminopropyl is preferably used. Trimethoxy decane, 3-mercaptopropyltrimethoxy fluorene Alkyl, 3-glycidoxypropyltrimethoxydecane, 3-isocyanatopropyltrimethoxydecane, and the like. These decane coupling agents may be used singly or in combination of two or more.

A preferred lower limit of the content of the above decane coupling agent in 100 parts by weight of the sealant for a liquid crystal display device of the present invention is 0.1 part by weight, preferably 10 parts by weight. When the content of the above decane coupling agent is within this range, the occurrence of liquid crystal contamination is suppressed, and the effect of improving the adhesion is further improved. A more preferred lower limit of the content of the above decane coupling agent is 0.3 parts by weight, and a more preferred upper limit is 5 parts by weight.

The sealing agent for liquid crystal display elements of this invention may also contain an opacifier. The sealing agent for a liquid crystal display element of the present invention can be preferably used as a light-shielding sealant by containing the above-mentioned sunscreen agent.

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 in terms of high insulation.

The above-mentioned titanium black can exert sufficient effects even if it is not surface-treated, but it can also be treated with an organic component such as a surface coupling agent, or cerium oxide, titanium oxide, cerium oxide, aluminum oxide, zirconium oxide or magnesium oxide. A surface treated titanium black such as an inorganic component. Among them, those who have been treated with an organic component are preferred in that the insulating property can be further improved.

In addition, the liquid crystal display element produced by using the sealing agent for liquid crystal display elements of the present invention containing the above-mentioned titanium black as a light-shielding agent has sufficient light-shielding property, so that there is no light leakage, high contrast, and excellent image. Display quality liquid crystal display elements.

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

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

Moreover, the preferred lower limit of the volume resistance of the titanium black is 0.5 Ω. Cm, preferably the upper limit is 3Ω. Cm, the lower limit is 1Ω. Cm, the upper limit is better 2.5Ω. Cm.

The primary particle diameter of the light-shielding agent is not particularly limited as long as it is equal to or less than the distance between the substrates of the liquid crystal display device, and a preferred lower limit is 1 nm, and a preferred upper limit is 5 nm. When the primary particle diameter of the above-mentioned light-shielding agent is in this range, the coating property of the obtained sealing compound for liquid crystal display elements can be made worse, and the light-shielding property can be further improved. A lower limit of the primary particle diameter of the above-mentioned opacifier is 5 nm, more preferably 200 nm, and further preferably a lower limit of 10 nm, and further preferably an upper limit of 100 nm.

Further, the primary particle diameter of the light-shielding agent can be measured by dispersing the light-shielding agent in a solvent (water, an organic solvent, etc.) using NICOMP 380ZLS (manufactured by PARTICLE SIZING SYSTEMS).

A preferred lower limit of the content of the above-mentioned sunscreen agent in 100 parts by weight of the sealant for a liquid crystal display device of the present invention is 5 parts by weight, and preferably the upper limit is 80 parts by weight. When the content of the above-mentioned light-shielding agent is in this range, it is possible to exhibit more excellent light-shielding properties without lowering the adhesion to the substrate of the obtained liquid crystal display element sealing agent or the strength or the drawability after curing. A more preferred lower limit of the content of the above-mentioned opacifier is 10 parts by weight, more preferably 70 parts by weight, still more preferably 30 parts by weight, and still more preferably 60 parts by weight.

The method for producing the sealant for a liquid crystal display device of the present invention includes, for example, a homogenizer, a homomixer, a universal mixer, a planetary mixer, a kneader, a three-roll mill, and the like, and a curable resin or a light is used. Base polymerization initiator, and add as needed A method of mixing additives such as a decane coupling agent.

The upper and lower conductive materials can be produced by blending the conductive fine particles with the sealing agent for a liquid crystal display element of the present invention. Such a sealing agent for a liquid crystal display element of the present invention and an upper conductive material for conductive fine particles are also one of the inventions.

As the conductive fine particles, a metal ball or a conductive metal layer formed on the surface of the resin fine particles can be used. Among them, in the case where the conductive metal layer is formed on the surface of the resin fine particles, it is preferable that the conductive fine particles can be electrically connected without being damaged by the transparent substrate or the like.

A liquid crystal display element using the sealant for a liquid crystal display element of the present invention or the underlying conductive material of the present invention is also one of the inventions.

As a method of producing the liquid crystal display element of the present invention, a liquid crystal dropping method is suitably used. Specifically, for example, the method includes the following steps: one of two substrates, such as a glass substrate with an electrode such as an ITO film or a polyethylene terephthalate substrate, which is screen-printed and divided. A sealant having a frame shape is applied by applying a sealant for a liquid crystal display device of the present invention, and the sealant for a liquid crystal display device of the present invention is applied to a frame of a seal pattern of a substrate in a state where the sealant for a liquid crystal display device of the present invention is not cured. A small droplet of the liquid crystal is superposed on the other substrate under vacuum; and the seal pattern portion of the sealant for a liquid crystal display element of the present invention is irradiated with light such as ultraviolet rays to cure the sealant. Further, in addition to the step of photocuring the sealant, the step of heating the sealant to thermally harden the laminate may be carried out.

According to the present invention, it is possible to provide a sealant for a liquid crystal display element which is excellent in light-shielding portion hardenability and can suppress liquid crystal contamination. Moreover, according to the present invention, it is possible to provide a liquid crystal using the same The display element sealing agent is used to form a top conductive material and a liquid crystal display element.

The invention is explained in more detail below with reference to examples, but the invention is not limited to the examples.

(Synthesis of bisphenol A epoxy acrylate A)

After dissolving 340 g of bisphenol A diglycidyl ether ("EPICLONEXA-850 CRP", manufactured by Dietics, Inc.) in 500 mL of toluene, 0.1 g of triphenylphosphine was added to prepare a homogeneous solution. To the obtained solution, 144 g of acrylic acid was added dropwise thereto under reflux for 2 hours, and further reflux stirring was carried out for 8 hours. Next, bisphenol A type epoxy acrylate A was obtained by removing toluene.

The bisphenol A type epoxy acrylate A obtained by ¹ H-NMR, ¹³ C-NMR, LC-TOF/MS, and IR confirmed to be bisphenol A diglycidyl ether diacrylate (molecular weight 484) .

(Synthesis of bisphenol A epoxy acrylate B)

500 g of bisphenol A type epoxy resin ("JER834" manufactured by Mitsubishi Chemical Corporation) was dissolved in 500 mL of toluene, and then 0.1 g of triphenylphosphine was added to prepare a homogeneous solution. To the obtained solution, 144 g of acrylic acid was added dropwise thereto under reflux for 2 hours, and further reflux stirring was carried out for 8 hours. Next, bisphenol A type epoxy acrylate B was obtained by removing toluene.

The bisphenol A type epoxy acrylate B obtained by ¹ H-NMR, ¹³ C-NMR, LC-TOF/MS, and IR was identified as an oligomeric epoxy acrylate having a molecular weight of 644.

(Examples 1 to 9 and Comparative Examples 1 to 5)

According to the blending ratios shown in Tables 1 and 2, each material was mixed using a planetary mixer (manufactured by Shinki Co., Ltd., "defoaming and stirring"), and then mixed using a three-roll mill, thereby preparing Example 1 ~9. Sealants for liquid crystal display elements of Comparative Examples 1 to 5.

<evaluation>

Each of the sealants for liquid crystal display elements obtained in the examples and the comparative examples was subjected to the following evaluation. The results are shown in Tables 1 and 2.

(shading portion hardenability)

First, a substrate A obtained by performing chromium vapor deposition on a half surface of a Corning glass having a thickness of 0.7 mm and a substrate B obtained by subjecting a front surface to chromium evaporation are prepared. Then, 1 part by weight of spacer fine particles ("Micropearl SI-H050", manufactured by Sekisui Chemical Co., Ltd.) having an average particle diameter of 5 μm was uniformly dispersed in each of the liquid crystals obtained in the examples and the comparative examples by a planetary stirring device. 100 parts by weight of the sealant for a display element, the obtained sealant was applied to the center portion of the substrate A (the boundary between the chromium vapor deposition portion and the non-vapor deposition portion), and the substrate B was bonded, and the sealant was sufficiently crushed. Further, ultraviolet rays of 100 mW/cm ² were irradiated for 30 seconds from the substrate A side using a metal halide lamp.

Then, the substrates A and B were peeled off using a cutter, and the spectrum was measured by a micro-IR method for a sealant on a point 50 μm away from the edge of the direct-irradiation portion of the ultraviolet light (a portion which was shielded by chromium vapor deposition). The conversion rate of the (meth) acrylonitrile group in the sealant was determined by the following method. In other words, the peak area of 815 to 800 cm ^{-1 is} the peak area of the (meth) acrylonitrile group, and the peak area of 845 to 820 cm ^-1 is taken as the reference peak area, and the (meth) acrylonitrile group is calculated by the following formula. The conversion rate is set to "◎" for the conversion rate of 90% or more, "○" for those of 70% or more and less than 90%, and "△" for those of 50% or more and less than 70%. The degree of hardenability of the light-shielding part was evaluated by setting "50" to less than 50%.

Conversion ratio of (meth) acrylonitrile group = (1 - (peak area of (meth) propylene fluorenyl group after ultraviolet irradiation / reference peak area after ultraviolet irradiation) / ((meth) acryl oxime before ultraviolet irradiation) Peak area of the base / reference peak area before ultraviolet irradiation)) × 100

(Display performance of liquid crystal display element (low liquid crystal contamination))

1 part by weight of the spacer particles ("Micropearl SI-H050", manufactured by Sekisui Chemical Co., Ltd.) having an average particle diameter of 5 μm was uniformly dispersed in each of the sealing agents for liquid crystal display elements obtained in the examples and the comparative examples by a planetary stirring device. 100 parts by weight, the obtained sealant was filled in a syringe for dripping ("PSY-10E" manufactured by Musashi Kogyo Co., Ltd.), and subjected to defoaming treatment, and then a dispenser ("SHOTMASTER 300" manufactured by Musashi Kogyo Co., Ltd.) was used. The sealant was applied in a frame shape to one of two transparent electrode substrates with an ITO film. Then, a small droplet of TN liquid crystal (manufactured by Chisso Corporation, "JC-5001LA") was dropped and applied to the frame of the sealant by a liquid crystal dropping device, and was attached to a vacuum of 5 Pa by a vacuum bonding device. A liquid crystal cell is obtained by a transparent electrode substrate. The obtained unit was irradiated with ultraviolet rays of 100 mW/cm ² for 30 seconds using a metal halide lamp, and then heated at 120 ° C for 1 hour to harden the sealant, thereby obtaining a liquid crystal display element.

In the obtained liquid crystal display element, the display unevenness of the liquid crystal (especially the corner portion) generated around the sealing portion was visually observed, and the case where the display unevenness was not confirmed was set to "◎", and a small amount of display was confirmed. In the case of the liquid crystal display element, the display performance of the liquid crystal display element is low (""", and it is confirmed that the display unevenness is set to "△", and the display is severely displayed as "X". Liquid crystal contamination) was evaluated.

Further, the liquid crystal display elements evaluated as "?" and "○" were such that there was no problem at all in actual use.

[Industrial availability]

According to the present invention, it is possible to provide a sealant for a liquid crystal display element which is excellent in light-shielding portion hardenability and can suppress liquid crystal contamination. Moreover, according to the present invention, it is possible to provide an upper and lower conductive material and a liquid crystal display element using the sealing agent for a liquid crystal display element.

Claims (5)

A sealant for a liquid crystal display element comprising a curable resin and a photoradical polymerization initiator, wherein the curable resin contains a compound having a molecular weight of 100 or more and less than 500 and a compound having a molecular weight of 500 to 3,000. The photoradical polymerization initiator is a compound having a carbazole skeleton. The sealant for liquid crystal display elements of the first aspect of the invention, wherein the compound having a carbazole skeleton has an aromatic ring other than the aromatic ring contained in the carbazole skeleton. A sealant for a liquid crystal display element according to claim 1 or 2, which contains an opacifier. A top-bottom conductive material comprising a sealant for a liquid crystal display element according to claim 1, 2 or 3, and conductive fine particles. A liquid crystal display element is obtained by using a sealant for a liquid crystal display element of the first, second or third aspect of the patent application or a conductive material above the fourth item of the patent application.