KR20150032885A - Liquid-crystal sealant and lcd cell using same - Google Patents

Abstract

The liquid crystal staining property under the wiring can be reduced and the liquid crystal display element can be made to have high definition, high-speed response, low voltage driving and long life, and furthermore, The present invention provides a liquid crystal sealing agent for a liquid crystal dropping method having excellent cured characteristics. The liquid crystal sealing agent for a liquid crystal dropping method of the present invention contains a photopolymerization initiator (a) and a thermal radical polymerization initiator (b) and has a curing rate of 60% or less when irradiated with ultraviolet rays of 2000 mJ / cm 2.

Description

LIQUID-CRYSTAL SEALANT AND LCD CELL USING SAME Technical Field [1] The present invention relates to a liquid crystal cell,

The present invention relates to a liquid crystal sealant containing a photopolymerization initiator and a thermal radical polymerization initiator, and to a liquid crystal sealant used in a liquid crystal drop method for combined heat treatment and a liquid crystal display cell using the liquid crystal sealant. More particularly, the present invention relates to a liquid crystal sealing agent for a liquid crystal dropping method having excellent low-liquid crystal stain resistance and good cured properties such as adhesive strength, and a liquid crystal display cell using the liquid crystal sealing agent, even though the curability by light is insufficient .

As the recent enlargement of liquid crystal display cells, a so-called liquid crystal dropping method has been proposed as a manufacturing method of a liquid crystal display cell, which has higher mass productivity (Patent Documents 1 and 2). Specifically, the liquid crystal dropping method is a method of manufacturing a liquid crystal display cell in which a liquid crystal is sealed by dropping liquid crystal on the inside of a frame made of a liquid crystal sealant formed on one of the substrates and then bonding another substrate to be.

However, in the liquid crystal dropping method, since the liquid crystal sealant in an uncured state is in contact with the liquid crystal, the liquid crystal sealant component dissolves (dissolves) in the liquid crystal at that time to lower the resistance value of the liquid crystal, .

In order to solve this problem, a liquid crystal sealing agent for a liquid crystal dropping method has been used at present and is practically used (Patent Documents 3 and 4). In the liquid crystal dropping method using the liquid crystal sealing agent, the liquid crystal sealing agent sandwiched between the substrates is first irradiated with light, and then primary cured, followed by heating to secondary cure. According to this method, the uncured liquid crystal sealant can be rapidly cured by light, and dissolution (dissolution) of the liquid crystal sealant component into the liquid crystal can be suppressed. In addition, there is a problem of lack of adhesive strength due to curing shrinkage or the like at the time of photo-curing only by photo-curing. However, a stress relaxation effect can be obtained by secondary curing by heat- .

In recent years, however, demands for high definition, high-speed response, low-voltage operation and longevity of liquid crystal display cells have become more stringent, and accordingly, the problem of solubility of liquid crystal sealant components in liquid crystals has also become higher . For example, Patent Document 5 discloses an epoxy acrylate component, and Patent Document 6 discloses an invention that inhibits the dissolution of an epoxy resin component into a liquid crystal.

In addition, the demand for the properties of the liquid crystal sealant itself, for example, the adhesive strength, etc., has become stricter every year. That is, in the liquid crystal panel of recent narrow frame design, the line width of the liquid crystal sealant becomes narrow, so that the problem of the adhesive strength is more severe than before. As the line width of the liquid crystal sealant becomes narrow, the conventional adhesive strength causes a problem that the upper and lower substrates are peeled off after the room temperature and moisture resistance reliability test. Therefore, development of a liquid crystal sealing agent having a high adhesive strength as a liquid crystal sealing agent for a liquid crystal dropping method with a low liquid crystal contamination property is carried out very energetically.

In addition, in Patent Document 7, attempts have been made to suppress the dissolution of the photoinitiator into the liquid crystal in consideration of the photoinitiator. However, considering the above situation, further improvement is required.

As described above, although a liquid crystal sealing agent is developed in a very energetic manner, a liquid crystal sealing agent having excellent low liquid crystal stain resistance and excellent cured properties such as adhesive strength has not yet been realized.

Japanese Patent Application Laid-Open No. 63-179323 Japanese Patent Laid-Open No. 10-239694 3) Japanese Patent Publication No. 3583326 Japanese Laid-Open Patent Publication No. 2004-61925 International Publication No. 2004/104683 International Publication No. 2004/090621 International Publication No. 2006/027982

The present invention relates to a liquid crystal sealing agent containing a photopolymerization initiator and a thermal radical polymerization initiator, and is excellent in curing property of the light shielding portion, so that the liquid crystal staining property under the wiring can be reduced and the liquid crystal sealing element can be provided with high definition, A liquid crystal sealing agent for a liquid crystal dripping method which enables dynamic and long life, and further has excellent cured characteristics such as adhesive strength, and a liquid crystal display cell using the liquid crystal sealing agent.

As a result of intensive studies, the inventors of the present invention have found that a liquid crystal sealant whose curability after irradiation with ultraviolet light is suppressed to a certain level or less solves the above problems, and has reached the present invention. In the present specification, "(meth) acryl" means "acrylic and / or methacryl".

That is, the present invention relates to the following (1) to (12).

(1) A liquid crystal sealing agent for a liquid crystal dropping method, which contains a photopolymerization initiator (a) and a thermal radical polymerization initiator (b) and has a curing rate of 60% or less when irradiated with ultraviolet rays of 2000 mJ / cm 2.

(2) The liquid crystal sealing agent for liquid crystal dropping method according to (1), wherein the curing rate when cured at 120 DEG C for 1 hour is 70% or more.

(3) The liquid crystal dropping method according to the above (1) or (2), further comprising a (meth) acrylated epoxy resin (c), an epoxy resin (d), a thermosetting agent (e) Liquid crystal sealant.

(4) The thermosetting resin composition as described in any one of (1) to (3) above, wherein the thermal radical polymerization initiator (b) is 1,2-bis (trimethylsiloxy) -1,1,2,2- Liquid crystal sealing agent for liquid crystal dropping method.

(5) The liquid crystal sealing agent for liquid crystal dropping method according to (3), wherein the (meth) acrylated epoxy resin (c) is a (meth) acrylic esterified product of resorcin sodium glycidyl ether.

(6) The liquid crystal sealing agent for liquid crystal dropping method according to (3) or (5), wherein the heat curing agent (e) is an organic acid hydrazide compound.

(7) The epoxy resin composition as described in any one of (3), (5) and (6) above, wherein 70% by mass or more of the total of the (meth) acrylated epoxy resin (c) and the epoxy resin (d) In the liquid crystal dropping method.

(8) The liquid crystal sealing agent for a liquid crystal dropping method according to any one of (1) to (7), which contains 0.001 to 3 mass% of the photopolymerization initiator (a).

(9) The liquid crystal sealing agent for liquid crystal dropping method according to any one of (1) to (8), further comprising a silane coupling agent (g).

(10) The liquid crystal sealing agent for a liquid crystal dripping method according to any one of (1) to (9), further comprising a radical polymerization inhibitor (h).

(11) A liquid crystal display cell comprising two substrates, wherein the liquid crystal is dropped into the frame made of the liquid crystal sealant for liquid crystal dropping method described in any one of (1) to (10) And then the liquid crystal sealing agent for liquid crystal dropping method is cured by ultraviolet rays and / or heat.

(12) A liquid crystal display cell adhered with a cured product obtained by curing the liquid crystal sealing agent for a liquid crystal dropping method according to any one of (1) to (10).

The present invention relates to a liquid crystal sealing agent containing a photopolymerization initiator and a thermal radical polymerization initiator, and relates to a liquid crystal sealing agent for a liquid crystal dropping method having excellent low-liquid crystal stain resistance and good cured properties such as adhesive strength. The liquid crystal sealing agent for the liquid crystal dropping method is particularly preferably used in a liquid dropping method using light and heat in combination to realize a liquid crystal display cell having excellent long-term reliability.

The liquid crystal sealing agent for a liquid crystal dropping method of the present invention (hereinafter simply referred to as "liquid crystal sealing agent") contains a photopolymerization initiator (a) and a thermal radical polymerization initiator (b), and irradiates ultraviolet rays of 2000 mJ / The curing rate is 60% or less.

In the present specification, the curing rate is also sometimes referred to as a gel fraction.

This gel fraction is calculated from the mass ratio before and after immersing in acetone by immersing the test piece obtained by applying the liquid crystal sealant of the present invention to a thickness of 100 mu m and irradiating ultraviolet rays to acetone for 10 hours. That is, in the liquid crystal sealing agent of the present invention, the mass after acetone immersion is 60% or less of the mass before acetone immersion.

A liquid crystal sealing agent having a gel fraction of 60% or less by ultraviolet ray irradiation exhibits a very high adhesive force after thermal curing. This result will be described in detail in the embodiment.

The liquid crystal sealing agent of the present invention contains a photopolymerization initiator (a) and a thermal radical polymerization initiator (b).

The photopolymerization initiator (a) is not particularly limited as long as it is a compound which generates radicals upon irradiation with ultraviolet rays or visible light and initiates a chain polymerization reaction. Examples thereof include benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, Diethyl thioxanthone, benzophenone, 2-ethyl anthraquinone, 2-hydroxy-2-methylpropiophenone, 2-methyl- [4- (methylthio) phenyl] -2-morpholino- , 2,4,6-trimethylbenzoyldiphenylphosphine oxide, camphorquinone, 9-fluorenone, and diphenyldisulfide. ^{Specifically, IRGACURE RTM 651, 184, 2959} , 127, 907, 396, 379EG, 819, 784, 754, 500, OXE01, OXE02, DAROCURE RTM 1173, LUCIRIN RTM TPO ( or more, BASF Corp.), Sheikh come ^RTM Z, BZ, BEE, BIP and BBI (all manufactured by Seiko Chemical Co., Ltd.). In the present specification, the superscript " RTM " means a registered trademark.

From the viewpoint of liquid crystal staining property, it is preferable to use one having a (meth) acryl group in the molecule, for example, 2- methacryloyloxyethyl isocyanate and 1- [4- (2-hydroxyethoxy) Phenyl] -2-hydroxy-2-methyl-1-propan-1-one is preferably used. This compound can be prepared by the method described in WO 2006/027982.

The content of the photopolymerization initiator (a) usable in the liquid crystal sealing agent of the present invention in the liquid crystal sealing agent is usually 0.001 to 3% by mass, preferably 0.002 to 2% by mass, based on 100% by mass of the entire liquid crystal sealing agent % to be. An embodiment in which only 0.5 mass% or less of the photopolymerization initiator (a) is included is one preferred embodiment of the present invention, more preferably 0.2 mass% or less.

The thermal radical polymerization initiator (b) is not particularly limited as far as it is a compound which generates radicals by heating to initiate a chain polymerization reaction, and may be an organic peroxide, an azo compound, a benzoin compound, a benzoin ether compound, Benzopinacol and the like, and benzopinacol is preferably used. For example, the Kaya MEC ^RTM A, M, R, L, LH, SP-30C, Parker DOX CH-50L, BC-FF, car DOX B-40ES, Parker DOX 14, teurigo Knox ^RTM 22 as an organic peroxide -70E, 23-C70, 121, 121-50E, 121-LS50E, 21-LS50E, 42, 42LS, Kaya ester ^{RTM P-70, TMPO-70} , CND-C70, OO-50E, AN, kaya butyl ^RTM B , Pakadox 16, Kayakarbon ^RTM BIC-75, AIC-75 (manufactured by Kayaku Akzo Co., Ltd.), Parmec ^RTM N, H, S, F, D, G, perhexa ^RTM H, , C, V, 22, MC, fur curing ^RTM AH, AL, HB, buffer butyl ^RTM H, C, ND, L, buffer cumyl ^RTM H, D, a buffer one ^RTM IB, IPP, buffer octa ^RTM ND (or more, Manufactured by Nichiyu Co., Ltd.) and the like are commercially available. As the azo compound, VA-044, V-070, VPE-0201, VSP-1001 (manufactured by Wako Pure Chemical Industries, Ltd.) and the like are commercially available.

Preferred as the thermal radical polymerization initiator (b) is a thermal radical polymerization initiator (including benzopinacol chemically modified) of the benzopinacol system. Specific examples thereof include benzopinacol, 1,2-dimethoxy-1,1,2,2-tetraphenylethane, 1,2-diethoxy-1,1,2,2-tetraphenylethane, 1,2- 1,1,2,2-tetraphenylethane, 1,2-dimethoxy-1,1,2,2-tetra (4-methylphenyl) ethane, 1,2-diphenoxy- , 2,2-bis (trimethylsiloxy) -1,1,2,2-tetraphenylethane, 1,2-bis (triethylsiloxy) 1,1,2,2-tetraphenylethane, 1,2-bis (t-butyldimethylsiloxy) -1,1,2,2-tetraphenylethane, 1 -hydroxy- , 1,2,2-tetraphenylethane, 1-hydroxy-2-triethylsiloxy-1,1,2,2-tetraphenylethane, 1 -hydroxy-2-t-butyldimethylsiloxy- , 1,2,2-tetraphenylethane, and the like, preferably 1-hydroxy-2-trimethylsiloxy-1,1,2,2-tetraphenylethane, 1 -hydroxy- Ethylsiloxy-1,1,2,2-tetraphenylethane, 1 -hydroxy-2-t-butyldimethylsiloxy-1,1,2,2-tetraphenylethane, 1,2-bis Trimethylsiloxy) -1,1,2,2-tetraphenylethane, more preferably 1-hydroxy-2-trimethylsiloxy-1,1,2,2-tetraphenylethane, 1,2-bis (Trimethylsiloxy) -1,1,2,2-tetraphenylethane, particularly preferably 1,2-bis (trimethylsiloxy) -1,1,2,2-tetraphenylethane.

Benzopinacol is commercially available from Tokyo Chemical Industry Co., Ltd., Wako Junyaku Kogyo Co., Further, the compound obtained by etherifying the hydroxy group of benzopinacol can be easily synthesized by a known method. A compound obtained by silylating a hydroxy group of benzopinacol can be obtained by synthesizing a corresponding benzopinacol and various silylating agents by heating in a basic catalyst such as pyridine. Examples of the silylating agent include trimethylsiloxane (TMCS), hexamethyldisilazane (HMDS), N, O-bis (trimethylsilyl) trifluoroacetamide (BSTFA), trimethylsiloxane Triethylchlorosilane (TECS) as a silylating agent, t-butylmethylsilane (TBMS) as a t-butyldimethylsilylating agent, and the like. These reagents are readily available in the market of silicon derivative makers and the like. The reaction amount of the silylating agent is preferably from 1.0 to 5.0 times the mole of the hydroxyl group of the target compound. And more preferably 1.5 to 3.0 times mol. If the molar ratio is less than 1.0 mol, the reaction efficiency is poor and the reaction time is prolonged, thereby promoting pyrolysis. If it is more than 5.0 times the molar amount, the separation may become worse at the time of recovery or the purification may become difficult.

The liquid crystal sealing agent of the present invention preferably has a gel fraction of 70% or more of a cured product which is thermally cured at 120 ° C for 1 hour. The heat curing in this case means that heat of 120 占 폚 is applied to the liquid crystal sealant without irradiating ultraviolet rays and the test piece is manufactured or tested in the same manner as in the gel fraction measurement after the ultraviolet ray irradiation. When the gel fraction after thermosetting is 70% or more, low-liquid crystal stain resistance is exhibited and high reliability can be obtained. This result will be described in detail in the examples.

The liquid crystal sealing agent of the present invention preferably further contains a (meth) acrylated epoxy resin (c), an epoxy resin (d), a thermosetting agent (e), and rubber microparticles (f).

The (meth) acrylated epoxy resin (c) can be obtained by a known reaction between an epoxy resin and (meth) acrylic acid. For example, an epoxy resin is mixed with (meth) acrylic acid and a catalyst (for example, benzyldimethylamine, triethylamine, benzyltrimethylammonium chloride, triphenylphosphine, triphenylstibine, etc.) (For example, methoquinone, hydroquinone, methylhydroquinone, phenothiazine, dibutylhydroxytoluene and the like) is added and esterification reaction is carried out, for example, at 80 to 110 ° C. The epoxy resin to be used as the raw material is not particularly limited, but epoxy resins having two or more functionalities are preferable. For example, diglycidyl ether of resorcinol (resorcin), bisphenol A type epoxy resin, bisphenol F type epoxy Resin, bisphenol S type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, bisphenol F novolak type epoxy resin, alicyclic epoxy resin, aliphatic chain type epoxy resin, A glycidylamine type epoxy resin, a hydantoin type epoxy resin, an isocyanurate type epoxy resin, a phenol novolak type epoxy resin having a triphenol methane skeleton, and diglycidyl Dialdehydes, diglycidyl ether compounds of bifunctional alcohols, and their halides, hydrogenated products and the like. Of these, bisphenol-type epoxy resins, novolac-type epoxy resins and diglycidyl ethers of resorcinol (resorcin) are more preferable from the viewpoint of liquid crystal staining.

The content of the (meth) acrylated epoxy resin (c) is appropriately determined in consideration of the workability and physical properties of the liquid crystal sealant, and is usually about 25 to 80 mass%, preferably 25 to 75 mass% to be.

The epoxy resin (d) is not particularly limited, but it is preferable that the epoxy resin (d) has low staining property and solubility in the liquid crystal. Examples of preferred epoxy resins include epoxy resins such as bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, resorcinol (resorcin) diglycidyl ether, phenol novolac epoxy resin, cresol novolak type Epoxy resin, bisphenol A novolak type epoxy resin, bisphenol F novolak type epoxy resin, alicyclic epoxy resin, aliphatic chain type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, Resins, isocyanurate type epoxy resins, phenol novolak type epoxy resins having triphenol methane skeleton, diglycidyl ether compounds of bifunctional phenols, diglycidyl ether compounds of bifunctional alcohols, and halogen Cargoes, hydrogenated products, and the like.

The content of the epoxy resin (d) is appropriately determined in consideration of the workability and physical properties of the liquid crystal sealant, and is usually about 25 to 80 mass%, preferably 25 to 75 mass%, in the liquid crystal sealant. It is one of preferred embodiments of the present invention that the epoxy resin (d) accounts for 70% by mass or more of the total of the (meth) acrylated epoxy resin (c) and the epoxy resin (d) Do.

The thermosetting agent (e) means a thermosetting agent that does not generate a radical, unlike the thermal radical polymerization initiator (b). Specifically, there may be mentioned, for example, polyvalent amines, polyhydric phenols, and organic acid hydrazide compounds reacting nucleophilically with an unshared electron pair or an anion in a molecule. However, the present invention is not limited thereto. Of these, organic acid hydrazide compounds are particularly preferably used. For example, an aromatic hydrazide such as terephthalic acid dihydrazide, isophthalic acid dihydrazide, 2,6-naphthoic acid dihydrazide, 2,6-pyridine dihydrazide, 1,2,4-benzene trihydrazide, 1,4,5,8-naphthoic acid tetrahydrazide, pyromellitic acid tetrahydrazide, and the like. In addition, the aliphatic hydrazide compound can be, for example, a hydrazide compound such as formal hydrazide, acethydrazide, propionic acid hydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide , Pimelic acid dihydrazide, sebacic acid dihydrazide, 1,4-cyclohexane dihydrazide, tartaric acid dihydrazide, malic acid dihydrazide, iminodiacetic acid dihydrazide, N, N'-hexamethylene bis- A hydantoin skeleton such as acetic acid trihydrate, nitrilotriacetic acid trihydrazide, cyclohexanetricarboxylic acid trihydrazide, and 1,3-bis (hydrazinocarbonoethyl) -5-isopropylhydantoin, A dihydrazide compound having a valine hydantoin skeleton (a skeleton in which a carbon atom of the hydantoin ring is substituted with an isopropyl group), an isocyanurate skeleton There may be mentioned compounds. Examples of the compound having an isocyanuric acid skeleton include tris (1-hydrazinocarbonylmethyl) isocyanurate, tris (2-hydrazinocarbonylethyl) isocyanurate, tris (3-hydrazino Carbonyl propyl) isocyanurate, and bis (2-hydrazinocarbonylethyl) isocyanurate. From the balance of the curing reactivity and the potential, it is preferable to use an isophthalic acid dihydrazide, malonic acid dihydrazide, adipic acid dihydrazide, tris (1-hydrazinocarbonylmethyl) isocyanurate, tris (2- (3-hydrazinocarbonylpropyl) isocyanurate, and particularly preferable is malonic acid dihydrazide. The content of such a thermosetting agent (e) is preferably from 1 to 20 parts by mass when the total amount of the (meth) acrylated epoxy resin (c) and the epoxy resin (d) is 100 parts by mass And more preferably 2 to 15 parts by mass, and they may be used in combination of two or more.

The rubber microparticles (f) can be obtained, for example, from natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene / butadiene rubber (SBR), butyl rubber (IIR) (EPM, EP), chloroprene rubber (CR), acrylic rubber (ACM, ANM), chlorosulfonated polyethylene rubber (CSM), urethane rubber (PUR), silicone rubber Rubber (FKM, FPM), and polysulfide rubber (Thiokol), and may be used alone or in combination of two or more to form a core-shell structure. Two or more species may be used in combination. Of these, acryl rubber and silicone rubber are preferable.

In the case of using an acrylic rubber, it is preferable that the acrylic rubber is a core-shell acrylic rubber composed of two types of acrylic rubber. It is particularly preferable that the core layer is n-butyl acrylate and the shell layer is methyl methacrylate. It is sold by Aika Kogyo Co., Ltd. as Zephyr ^RTM F-351.

Examples of the silicone rubber include a bridged organopolysiloxane powder and a dimethylpolysiloxane crosslinked powder of a linear chain. As the composite silicone rubber, a silicone rubber (for example, a polyorganosilsesquioxane resin) is coated on the surface of the silicone rubber. Particularly preferred among these rubber fine particles are composite silicone rubber fine particles of a silicone rubber-crosslinked dimethylpolysiloxane crosslinked powder or a silicone resin-coated linear polysiloxane crosslinked powder of a linear chain. These may be used alone, or two or more of them may be used in combination. Preferably, the shape of the rubber powder is spherical with a small viscosity increase after the addition.

The true specific gravity of the silicone rubber powder is preferably 0.9 to 1.1. If the true specific gravity is larger than 1.1, the rubber particles become hard and the gap formation at the time of coalescence of the upper and lower glass substrates at the time of manufacturing the liquid crystal cell is hindered. The average particle diameter of the silicone rubber powder is preferably 4 to 9 占 퐉. If the average particle diameter is larger than 9 占 퐉, the cell gap will not collapse well. If the average particle diameter is smaller than 4 탆, the seal puncture of the liquid crystal tends to occur at the time of manufacturing the cell. The JIS-A rubber hardness of the silicone rubber powder is measured by a durometer, and it is preferably 10 to 50. If the JIS-A rubber hardness is larger than 50, it is excessively hard and the cell gap is not crushed well. If the JIS-A rubber hardness is less than 10, seal puncture of the liquid crystal tends to occur at the time of manufacturing the cell.

The average particle diameter of the composite silicone rubber powder is preferably 1 to 9 占 퐉. If the average particle diameter is larger than 9 占 퐉, the cell gap will not collapse well. If the average particle diameter is less than 1 탆, seal puncture of the liquid crystal tends to occur at the time of manufacturing the cell. The JIS-A rubber hardness of the composite silicone rubber powder is measured by a durometer, and is preferably 10 to 90. If the JIS-A rubber hardness is greater than 90, it is too hard and the cell gap does not collapse well. If the JIS-A rubber hardness is less than 10, seal puncture of the liquid crystal tends to occur at the time of manufacturing the cell.

The content of the rubber fine particles (f) in the liquid crystal sealing agent is 2 to 20% by mass, preferably 5 to 15% by mass. When the content is excessively small, a seal puncture occurs due to a decrease in the viscosity of the liquid crystal sealant when heating the liquid crystal cell, and the liquid crystal leaks. If the content is too large, the viscosity of the liquid crystal sealant becomes excessively high, making it impossible to apply.

In the liquid crystal sealing agent of the present invention, the silane coupling agent (g) can be used to improve the bonding strength and the moisture resistance reliability. Examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) Aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-aminopropyltrimethoxysilane, vinyltrimethoxysilane, N- (2- (vinylbenzylamino) ethyl) 3-aminopropyltrimethoxysilane hydrochloride , 3-methacryloxypropyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, and the like. These silane coupling agents are sold by Shin-Etsu Chemical Industry Co., Ltd. as KBM series, KBE series, etc., and are therefore readily available on the market. The content of the silane coupling agent (g) in the liquid crystal sealant is preferably 0.05 to 3% by mass when the total amount of the liquid crystal sealant of the present invention is 100% by mass.

The liquid crystal sealing agent of the present invention may further contain a radical polymerization inhibitor (h). The radical polymerization inhibitor (h) is not particularly limited as long as it is a compound that reacts with a radical generated from a photopolymerization initiator or a thermal radical polymerization initiator to prevent polymerization, and examples thereof include a quinone system, a piperidine system, a hindered phenol system, Etc. may be used. Specific examples include naphthoquinone, 2-hydroxynaphthoquinone, 2-methylnaphthoquinone, 2-methoxynaphthoquinone, 2,2,6,6-tetramethylpiperidine-1-oxyl, 2 , 2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl, 2,2,6,6-tetramethyl-4-methoxypiperidin- 2-methylhydroquinone, 2-methoxyhydroquinone, parabenzoquinone, butylated hydroxyanisole, 2,6-di-t-butoxycarbonylamino, (3,5-ditert-butyl-4-hydroxyphenyl) propionate, 2,2'-methylenebis Methyl-6-t-butylphenol), 4,4'-butylidenebis (3-methyl-6-t-butylphenol), 4,4'- Butylphenol), 3,9-bis [1,1-dimethyl-2- [beta - (3-t-butyl- Tetraoxaspiro [5,5] undecane, tetrakis- [methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl Triazine-2,4,6- (1H, 3H, 5H-tetramethyl-4-hydroxyphenyl) 5H) trione, paramethoxyphenol, 4-methoxy-1-naphthol, thiodiphenylamine, aluminum salt of N-nitrosophenylhydroxyamine, trade name Adecastab LA-81, trade name Adecastab LA- 82 (manufactured by Adeka Co., Ltd.), and the like, but the present invention is not limited thereto. Of these, radical polymerization inhibitors based on naphthoquinone, hydroquinone and nitroso-piperazine are preferable, and naphthoquinone, 2-hydroxynaphthoquinone, hydroquinone, 2,6-di-tert- Cresol and polystop 7300P (manufactured by Hakuto Co., Ltd.) are more preferable, and polystop 7300P (manufactured by Hakuto Co., Ltd.) is most preferable.

The radical polymerization inhibitor (h) may be added in the synthesis of the (meth) acrylated epoxy resin (c) or the method of adding and dissolving the (meth) acrylated epoxy resin (c) and / or the epoxy resin , It is preferable to add and dissolve the (meth) acrylated epoxy resin (c) and / or the epoxy resin (d) in order to obtain a more effective effect.

The content of the radical polymerization inhibitor (h) is preferably from 0.0001 to 1 mass%, more preferably from 0.001 to 0.5 mass%, and particularly preferably from 0.01 to 0.2 mass%, based on the total amount of the liquid crystal sealing agent of the present invention.

In the liquid crystal sealing agent of the present invention, the inorganic filler can be used to improve the bonding strength and the humidity resistance reliability. Examples of the inorganic filler include fused silica, crystalline silica, silicon carbide, silicon nitride, boron nitride, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, magnesium oxide, zirconium oxide, Silica, calcium silicate, aluminum silicate, lithium aluminum silicate, zirconium silicate, barium titanate, glass fiber, carbon fiber, molybdenum disulfide and asbestos, and preferably fused silica, crystalline silica, silicon nitride, boron nitride, calcium carbonate Barium sulfate, calcium sulfate, mica, talc, clay, alumina, aluminum hydroxide, calcium silicate and aluminum silicate, and more preferably fused silica, crystalline silica, alumina and talc. These inorganic fillers may be used in combination of two or more kinds. If the average particle diameter is too large, it becomes a cause of defects such as a problem that the gap is not formed well when the upper and lower glass substrates are bonded during the production of the liquid crystal cell with a narrow gap. Therefore, the thickness is preferably 3 μm or less, to be. The particle size can be measured by a laser diffraction / scattering type particle size distribution analyzer (dry type) (LMS-30, manufactured by Seishin Co., Ltd.).

In the liquid crystal sealing agent of the present invention, the content of the inorganic filler is generally 10 to 60 mass%, preferably 20 to 50 mass%, based on 100 mass% of the entire liquid crystal sealing agent. When the content of the inorganic filler is less than 5% by mass, the bonding strength to the glass substrate is lowered and the moisture resistance reliability is also lowered, so that the lowering of the bonding strength after moisture absorption is also increased. On the other hand, when the content of the inorganic filler is more than 60% by mass, the filler content is excessively large, so that the gap between the liquid crystal cell and the liquid crystal cell can not be formed.

In the liquid crystal sealing agent of the present invention, monomers and / or oligomers of (meth) acrylic acid esters may be further used if necessary. Examples of such monomers and oligomers include a reaction product of dipentaerythritol and (meth) acrylic acid, a reaction product of dipentaerythritol · caprolactone and (meth) acrylic acid, and the like. However, Is not particularly limited.

The liquid crystal sealant of the present invention may further contain additives such as a hardening accelerator such as organic acid and imidazole, an organic filler, or a pigment, a leveling agent, an antifoaming agent, and a solvent, if necessary.

As an example of the method for obtaining the liquid crystal sealant for liquid crystal dropping method of the present invention, there is the following method. First, the photopolymerization initiator (a) is heated and dissolved in the (meth) acrylated epoxy resin (c) and the epoxy resin (d). After cooling, the thermal radical polymerization initiator (b) is added, and then the heat curing agent (e), the rubber microparticle (f), the silane coupling agent (g), the organic filler, the defoaming agent, And the mixture is homogeneously mixed by a known mixing device such as three rolls, a sand mill, a ball mill, etc., and filtered with a metal mesh to produce the liquid crystal sealing agent of the present invention.

In the liquid crystal display cell of the present invention, a pair of substrates provided with a predetermined electrode on a substrate are arranged opposite to each other at a predetermined interval, and the periphery thereof is sealed with the liquid crystal sealant of the present invention, and liquid crystal is sealed in the gap. The type of the liquid crystal to be enclosed is not particularly limited. Here, the substrate is composed of a combination substrate made of glass, quartz, plastic, silicon or the like and having at least one light transmitting property. In this method, a spacer (gap control member) such as glass fiber is added to the liquid crystal sealing agent of the present invention, and the liquid crystal sealing agent is applied to one side of the pair of substrates using a dispenser, a screen printing apparatus, Then, temporary curing is carried out at 80 to 120 ° C, if necessary. Thereafter, liquid crystal is dropped into the frame made of the liquid crystal sealant, and the other glass substrate is superimposed in vacuum, and gap formation is performed. After formation of the gap, ultraviolet rays are irradiated to the liquid crystal seal part by an ultraviolet ray irradiator to cause photo curing. The ultraviolet irradiation dose is preferably 500 to 6000 mJ / cm 2, more preferably 1000 to 4000 mJ / cm 2. Thereafter, if necessary, the liquid crystal display cell of the present invention can be obtained by curing at 90 to 130 ° C for 1 to 2 hours. The liquid crystal display cell of the present invention thus obtained is free from display defects due to liquid crystal contamination, and is excellent in adhesiveness and moisture resistance reliability. Examples of the spacer include glass fibers, silica beads, polymer beads, and the like. The diameter varies depending on the purpose, and is usually 2 to 8 탆, preferably 4 to 7 탆. The content thereof is usually about 0.1 to 4 mass%, preferably about 0.5 to 2 mass%, and more preferably about 0.9 to 1.5 mass%, based on 100 mass% of the liquid crystal sealing material of the present invention.

The liquid crystal sealing agent of the present invention has excellent adhesive strength. In addition, the thermosetting property is very good, and it hardens quickly in the heating step in the liquid crystal dropping method. Therefore, the component is less likely to dissolve in the liquid crystal, and display defects of the liquid crystal display cell can be reduced. Further, since the storage stability is also excellent, it is suitable for the production of a liquid crystal display cell. Further, since the cured product is also excellent in various cured properties such as heat resistance and moisture resistance, it is possible to manufacture a liquid crystal display cell having excellent reliability by using the liquid crystal sealing agent of the present invention. The heat resistance can be confirmed by measuring the glass transition temperature, and the moisture resistance can be confirmed by measuring the adhesive strength after being placed in a high humidity environment. The liquid crystal display cell manufactured using the liquid crystal sealing material of the present invention also satisfies the characteristics required for a liquid crystal display cell having a high voltage holding ratio and a low ion density.

Example

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In addition, unless otherwise specified, "parts" and "%" in the text are based on mass.

[Synthesis Example 1]

[Synthesis of epoxy acrylate of bisphenol A type epoxy resin]

282.5 g of bisphenol A type epoxy resin (product name: YD-8125, manufactured by Shin-Nittsu Chemical Co., Ltd.) was dissolved in 266.8 g of toluene, 0.8 g of dibutylhydroxytoluene as a polymerization inhibitor was added thereto and the temperature was raised to 60 캜 . Thereafter, 117.5 g of 100% equivalent of acrylic acid as an epoxy group was added and the temperature was further raised to 80 ° C. Then, 0.6 g of trimethylammonium chloride as a reaction catalyst was added thereto and the mixture was stirred at 98 ° C for about 30 hours, . The reaction solution was washed with water and toluene was distilled off to obtain 395 g of an intended bisphenol A type epoxy acrylate (acrylated bisphenol A type epoxy resin) (KAYARAD ^RTM R-93100).

[Synthesis Example 2]

[Synthesis of epoxy acrylate of resorcine diglycidyl ether]

181.2 g of resorcinol diglycidyl ether (EX-201: Nagase Chemtex Co., Ltd.) was dissolved in 266.8 g of toluene, to which 0.8 g of dibutylhydroxytoluene was added as a polymerization inhibitor, and the temperature was raised to 60 占 폚. Thereafter, 117.5 g of 100% equivalent of acrylic acid as an epoxy group was added and the temperature was further raised to 80 ° C. Then, 0.6 g of trimethylammonium chloride as a reaction catalyst was added thereto and the mixture was stirred at 98 ° C for about 30 hours, . The reaction solution was washed with water and toluene was distilled off to obtain 293 g of an epoxy acrylate of the desired resorcin sodium glycidyl ether.

[Examples 1 to 3, Comparative Examples 1 to 2]

(Meth) acrylated epoxy resin (c) and an epoxy resin (d) were mixed and stirred in the proportions shown in Table 1 below, and then heated and dissolved at 90 캜. Thereafter, the photopolymerization initiator (a) and the radical polymerization inhibitor (h) were heated and dissolved, and then the mixture was cooled to room temperature to obtain a radical polymerization initiator (b), a thermosetting agent (e), a rubber microparticle (f) g) and an inorganic filler were added, and the mixture was stirred, dispersed with a three roll mill, and filtered with a metal mesh (635 mesh) to prepare liquid crystal sealants of Examples 1 to 3. In addition, the liquid crystal sealants of Comparative Examples 1 and 2 were prepared by blending the materials shown in Table 1 by the same process. The curing rate (gel fraction) of each liquid crystal sealant when irradiated with ultraviolet light of 2000 mJ / cm 2 and cured at 120 캜 for 1 hour was measured by the above-described method. The results are shown in Table 1.

[Evaluation of liquid crystal sealant]

[Adhesive strength measurement]

1 g of glass fiber (PF-50S: manufactured by Nippon Electric Glass Co., Ltd.) as a spacer was added as a spacer to 100 g of the obtained liquid crystal sealer, followed by mixing and stirring. This liquid crystal sealant was applied on a glass substrate of 50 mm x 50 mm and a glass piece of 1.5 mm x 1.5 mm was bonded onto the liquid crystal sealant. This was placed in an oven at 120 deg. C and thermally cured for 1 hour to obtain Test Specimen 1, irradiated with ultraviolet rays of 2000 mJ / cm2 by a UV irradiator, put into an oven and thermally cured at 120 deg. C for 1 hour, . The shear bond strength of the glass of these test pieces was measured by a bond tester (SS-30WD: manufactured by Seishin Co., Ltd.). The results are shown in Table 1.

From the results shown in Table 1, it can be seen that the liquid crystal sealing agents of Examples 1 to 3 exhibit excellent adhesive strength even in the case of curing by combination of ultraviolet rays and heat, I could confirm. Therefore, the liquid crystal sealing agent of the present invention can realize long-term high reliability of the liquid crystal display cell.

Industrial availability

Since the liquid crystal sealing agent of the present invention has a high adhesive strength, it is possible to realize a liquid crystal display panel excellent in long-term reliability without causing peeling of the upper and lower substrates.

Claims (12)

A liquid crystal sealing agent for a liquid crystal dropping method comprising a photopolymerization initiator (a) and a thermal radical polymerization initiator (b) and having a curing rate of 60% or less when irradiated with ultraviolet light of 2000 mJ / cm 2. The method according to claim 1,
A liquid crystal sealing agent for a liquid crystal dropping method having a curing rate of 70% or more when cured at 120 占 폚 for 1 hour. 3. The method according to claim 1 or 2,
A liquid crystal sealing agent for a liquid crystal dropping method further comprising a (meth) acrylated epoxy resin (c), an epoxy resin (d), a thermosetting agent (e), and a rubber fine particle (f). 4. The method according to any one of claims 1 to 3,
Wherein the thermal radical polymerization initiator (b) is 1,2-bis (trimethylsiloxy) -1,1,2,2-tetraphenylethane. The method of claim 3,
Wherein the (meth) acrylated epoxy resin (c) is a (meth) acrylic esterified product of resorcin sodium glycidyl ether. The method according to claim 3 or 5,
Wherein the thermosetting agent (e) is an organic acid hydrazide compound. The method according to any one of claims 3, 5, and 6,
Wherein at least 70 mass% of the total of the (meth) acrylated epoxy resin (c) and the epoxy resin (d) is the epoxy resin (d). 8. The method according to any one of claims 1 to 7,
And a photopolymerization initiator (a) in an amount of 0.001 to 3 mass%. 9. The method according to any one of claims 1 to 8,
Further comprising a silane coupling agent (g). 10. The method according to any one of claims 1 to 9,
Further comprising a radical polymerization inhibitor (h). A method for manufacturing a liquid crystal display cell comprising two substrates, comprising the steps of dropping liquid crystal into a frame made of a liquid crystal sealant for a liquid crystal dropping method according to any one of claims 1 to 10 formed on one of the substrates, And the liquid crystal sealing agent for liquid crystal dropping method is cured by ultraviolet rays and / or heat. A liquid crystal display cell adhered with a cured product obtained by curing a liquid crystal sealant for a liquid crystal dropping method according to any one of claims 1 to 10.