Liquid crystal sealing agent for liquid crystal dripping method and liquid crystal display panel using same

Abstract

The invention relates to a liquid crystal sealing agent for liquid crystal dripping method and a liquid crystal display panel using the liquid crystal sealing agent. Provided are: a liquid crystal sealing agent for a liquid crystal instillation method, which has excellent adhesiveness and moisture permeation prevention properties; and a liquid crystal display panel sealed by a cured product of the liquid crystal sealing agent. A liquid crystal sealing agent for a liquid crystal instillation method, which contains (A) a filler having an average particle diameter of 0.4 [mu] m or less, (B) a curable compound, (C) a photo-radical polymerization initiator and (D) a thermosetting agent, and wherein the content of the component (A) is 7-25 parts by weight (inclusive) per 100 parts by weight of the component (B); the liquid crystal sealing agent for liquid crystal instillation contains (B-1) a compound having a (meth) acryloyl group and (B-2) a compound having a mercapto group as the component (B), and the elastic modulus of a cured product of the liquid crystal sealing agent for liquid crystal instillation at 25 DEG C measured by a universal tester is 2000 MPa or more and less than 4500 MPa.

Description

Technical Field

[0001] The present invention relates to a liquid crystal sealant for the liquid crystal dropping method and a liquid crystal display unit encapsulated with a cured product of the liquid crystal sealant for the liquid crystal dropping method. Background Art

[0002] In recent years, as a method for manufacturing a liquid crystal display element, from the viewpoints of shortening the man-hour per unit and optimizing the amount of liquid crystal used, a liquid crystal dropping method called the dropping method using a photo-thermo dual-curing type sealant containing a curable resin, a photoinitiator, and a thermosetting agent, as disclosed in Patent Documents 1 and 2, is used.

[0003] In the dropping method, first, a rectangular seal pattern is formed on one of two transparent substrates with electrodes by a dispenser. Next, in a state where the sealant is not cured, minute droplets of liquid crystal are dropped onto the entire surface inside the frame of the transparent substrate, and immediately overlapped with the other transparent substrate, and light such as ultraviolet rays is irradiated onto the sealed portion to perform pre-curing. Then, heating is performed for main curing, thereby manufacturing a liquid crystal display element. By bonding the substrates under reduced pressure, a liquid crystal display element can be manufactured with extremely high efficiency, and currently this dropping method has become the mainstream of the manufacturing method of liquid crystal display elements.

[0004] With the popularization of tablet terminals and portable terminals, there are increasing demands for the durability of liquid crystal display elements in impact tests, drop tests, etc., and there are also increasing demands for the adhesiveness to substrates. In addition, with the narrow bezelization of panels, there is a demand for moisture resistance reliability in driving in a high-temperature and high-humidity environment, and for the sealant, there is a further demand for the performance of preventing infiltration of water from the outside. In order to improve the impact resistance and moisture resistance reliability of liquid crystal display elements, it is necessary to improve the adhesiveness between the sealant and the substrate, etc., and reduce the moisture permeability of the cured product of the sealant. However, it is difficult to produce a sealant that is excellent in both adhesiveness and moisture barrier properties.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Laid-Open No. 2001-133794

[0008] Patent Document 2: Japanese Patent Laid-Open No. 5-295087 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] An object of the present invention is to provide a liquid crystal sealant for the liquid crystal dripping method having excellent adhesiveness and moisture barrier properties, and a liquid crystal display panel sealed with a cured product of the liquid crystal sealant for the liquid crystal dripping method. In particular, the liquid crystal sealant for the liquid crystal dripping method of the present invention has excellent adhesiveness to stress in two directions, namely, the shear direction and the peeling direction.

[0011] Means for Solving the Problem

[0012] That is, the present invention relates to the following [1] to [7]. It should be noted that in this application, "(numerical value 1) to (numerical value 2)" means including the upper limit value and the lower limit value. In addition, "(meth)acrylate" means "acrylate" and / or "methacrylate".

[0013] [1] A liquid crystal sealant for the liquid crystal dripping method, the liquid crystal sealant for the liquid crystal dripping method containing a filler (A) having an average particle diameter of 0.4 μm or less, a curable compound (B), a photo radical polymerization initiator (C), and a thermal curing agent (D), wherein

[0014] The content of the component (A) is 7 parts by weight or more and 25 parts by weight or less with respect to 100 parts by weight of the component (B),

[0015] The liquid crystal sealant for the liquid crystal dripping method contains a compound (B-1) having a (meth)acryloyl group and a compound (B-2) having a mercapto group as the component (B),

[0016] The elastic modulus of the cured product of the liquid crystal sealant for the liquid crystal dripping method measured at 25 °C using a universal testing machine is 2000 MPa or more and less than 4500 MPa.

[0017] [2] The liquid crystal sealant for the liquid crystal dripping method according to the previous item [1], wherein the moisture permeability of the cured product of the liquid crystal sealant for the liquid crystal dripping method measured under the conditions of 60 °C and 90% is 50 g / m 2 ·24 hours or less.

[0018] [3] The liquid crystal sealant for the liquid crystal dripping method according to the previous item [1] or [2], wherein the liquid crystal sealant for the liquid crystal dripping method contains partial epoxy (meth)acrylate as the component (B-1).

[0019] [4] The liquid crystal sealant for the liquid crystal dripping method according to any one of the previous items [1] to [3], wherein the liquid crystal sealant for the liquid crystal dripping method contains urethane (meth)acrylate as the component (B-1).

[0020] [5] The liquid crystal sealant for liquid crystal dropping method according to any one of the preceding items [1] to [4], wherein the liquid crystal sealant for liquid crystal dropping method further contains component (E) a thermal free radical polymerization initiator.

[0021] [6] The liquid crystal sealant for liquid crystal dropping method according to the preceding item [5], wherein the component (E) is a thermal free radical polymerization initiator that does not contain an oxygen-oxygen bond (-O-O-) and a nitrogen-nitrogen bond (-N=N-) in the molecule.

[0022] [7] A liquid crystal display panel, wherein the liquid crystal display panel is encapsulated using the liquid crystal sealant for liquid crystal dropping method according to any one of the preceding items [1] to [6].

[0023] Advantages of the Invention

[0024] The present invention can provide a liquid crystal sealant for liquid crystal dropping method with excellent adhesiveness and moisture barrier properties, and a liquid crystal display panel sealed with a cured product of the liquid crystal sealant for liquid crystal dropping method. Description of the Drawings

[0025] Figure 1 Shows the test method for shear adhesive strength.

[0026] Figure 2 Shows the test method for peel adhesive strength. Detailed Description of the Invention

[0027] The sealant for liquid crystal dropping method of the present invention (hereinafter also simply referred to as "liquid crystal sealant") contains component (A) a filler with an average particle size of 0.4 μm or less, component (B) a curable compound, component (C) a photo free radical polymerization initiator, and component (D) a thermal curing agent. Among them, relative to 100 parts by weight of the component (B), the content of the component (A) is 7 parts by weight or more and 25 parts by weight or less. The liquid crystal sealant for liquid crystal dropping method contains a compound having a (meth)acryloyl group (B-1) and a compound having a mercapto group (B-2) as the component (B), and the elastic modulus of the cured product of the liquid crystal sealant for liquid crystal dropping method at 25 °C measured by a universal testing machine is greater than or equal to 2000 MPa and less than 4500 MPa.

[0028] In the present invention, for the elastic modulus, at room temperature (25 °C), using a universal testing machine (manufactured by Shimadzu Corporation: Autograph AG-Xplus500N), a cured product with a thickness of 100 μm cured under the conditions of 120 °C and 70 minutes after irradiating ultraviolet rays with a wavelength of 365 nm and an intensity of 3000 mJ / cm 2 (measurement wavelength: 365 nm) is measured.

[0029] The elastic modulus of the liquid crystal sealant of the present invention is greater than or equal to 2000 MPa and less than 4500 MPa, more preferably 2500 MPa or more and 4000 MPa or less.

[0030] In the present invention, for moisture permeability, a cured product with a thickness of 300 μm after being cured under the conditions of 120 °C and 70 minutes after irradiation with ultraviolet rays of 3000 mJ / cm 2 (measurement wavelength: 365 nm) was measured using a moisture permeability meter (manufactured by Lyssy Co., Ltd.: L80-5000), or it can also be measured by leaving the cured product at 60 °C and 90% for 24 hours.

[0031] The moisture permeability of the liquid crystal sealant of the present invention is preferably 50 g / m 2 ·24 hours or less, more preferably 40 g / m 2 ·24 hours or less.

[0032] The liquid crystal sealant for the liquid crystal dropping method of the present invention has excellent adhesiveness to stress in two directions, namely the shear direction and the peeling direction. Specifically, in the measurement method described below, the shear adhesive strength is preferably 15 MPa or more. There is no particular limitation on the upper limit value, but it is preferably 30 MPa or less. The peel adhesive strength is preferably 1.5 kgf or more. There is no particular limitation on the upper limit value, but it is preferably 3.0 kgf or less.

[0033] [(A) Filler with an average particle size of 0.4 μm or less]

[0034] Component (A) A filler with an average particle size of 0.4 μm or less (hereinafter also simply referred to as component (A)) is a filler with an average particle size of 0.4 μm or less, and examples thereof include organic fillers and inorganic fillers.

[0035] In the present invention, the average particle size can be measured using a laser diffraction / scattering type particle size distribution analyzer (dry type) (manufactured by Seishin Enterprise Co., Ltd.; LMS-30). In addition, if it is a commercially available product, it is not limited to the above method, and the values described in the product catalogs of each company can be used.

[0036] There is no particular limitation on the lower limit value of the average particle size, preferably 0.001 μm or more, more preferably 0.01 μm or more, and particularly preferably 0.1 μm or more. In addition, the upper limit value is preferably 0.4 μm or less, more preferably 0.3 μm or less. This is because when the upper limit value of the average particle size is 0.4 μm or less, the adhesiveness of the liquid crystal sealant in the shear direction is excellent, and when the lower limit value of the average particle size is 0.001 μm or more, the dispersibility and dispensability are excellent.

[0037] In addition, the shape of the particles can be spherical, plate-like or other shapes, and when considering the gap, it is preferably spherical.

[0038] With respect to 100 parts by weight of the curable compound of component (B) described below, the content of component (A) is preferably 7 parts by weight or more and 25 parts by weight or less, more preferably 12 parts by weight or more and 20 parts by weight or less. When the content of component (A) is 7 parts by weight or more, the adhesive strength in the peeling direction becomes high, and when the content of component (A) is 25 parts by weight or less, the thixotropy ratio becomes small and the wettability to the substrate is improved.

[0039] [Organic filler]

[0040] Examples of the organic filler include: urethane polymer fine particles, acrylic polymer fine particles, styrene polymer fine particles, styrene-olefin copolymer fine particles, and silicone fine particles. It should be noted that as the silicone fine particles, KMP-594, KMP-597, KMP-598 (manufactured by Shin-Etsu Chemical Co., Ltd.) are preferred; Torayfil RTM E-5500, 9701, EP-2001 (manufactured by Toray Dow Corning Co., Ltd.), as the urethane polymer fine particles, JB-800T, HB-800BK (manufactured by Negami Kogyo Co., Ltd.) are preferred, and as the styrene polymer fine particles, Rabalon RTM T320C, T331C, SJ4400, SJ5400, SJ6400, SJ4300C, SJ5300C, SJ6300C (manufactured by Mitsubishi Chemical Corporation) are preferred, and as the styrene-olefin copolymer fine particles, Septon RTM SEPS2004, SEPS2063.

[0041] These organic fillers can be used alone or in combination of two or more. In addition, a core-shell structure can be formed using two or more organic fillers. Among them, acrylic polymer fine particles and silicone fine particles are preferred.

[0042] In the case of using the above-mentioned acrylic polymer fine particles, it is preferably the case of an acrylic rubber having a core-shell structure containing two acrylic rubbers, and particularly preferably an acrylic rubber having a core-shell structure in which the core layer is n-butyl acrylate and the shell layer is methyl methacrylate. It is sold as Zefiac RTM F-351 by Aike Industry Co., Ltd.

[0043] In addition, examples of the above-mentioned silicone fine particles include organopolysiloxane cross-linked powder, linear dimethylpolysiloxane cross-linked powder, etc. In addition, examples of the composite silicone rubber include a composite silicone rubber obtained by coating the surface of the above-mentioned silicone rubber with a silicone resin (for example, polyorganosilsesquioxane resin). Among these fine particles, silicone rubber fine particles in the form of linear dimethylpolysiloxane cross-linked powder, or composite silicone rubber fine particles in the form of linear dimethylpolysiloxane cross-linked powder coated with a silicone resin are particularly preferred. These organic fillers can be used alone or in combination of two or more. In addition, it is preferable that the shape of the rubber powder is spherical with less increase in viscosity after addition.

[0044] [Inorganic filler]

[0045] Examples of the inorganic filler include: silica, silicon carbide, silicon nitride, boron nitride, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, magnesia, zirconia, aluminum hydroxide, magnesium hydroxide, calcium silicate, aluminum silicate, lithium aluminum silicate, zirconium silicate, barium titanate, glass fiber, carbon fiber, molybdenum disulfide, asbestos, etc. Preferred examples include: fused silica, crystalline silica, silicon nitride, boron nitride, calcium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, aluminum hydroxide, calcium silicate, calcium silicate, and preferably silica, alumina, and talc. Two or more of these inorganic fillers can be used in combination.

[0046] [(B) Curing compound]

[0047] The liquid crystal sealant of the present invention contains a curing compound (hereinafter also simply referred to as "component (B)") as component (B).

[0048] As component (B), there is no particular limitation as long as it is a compound that cures by light, heat, etc. For example, it can include: compounds having a (meth)acryloyl group, compounds having a mercapto group, compounds having an epoxy group, compounds having a maleimide group, etc.

[0049] [Compound having a (meth)acryloyl group]

[0050] Examples of the compound having a (meth)acryloyl group include: (meth)acrylate, epoxy (meth)acrylate, urethane (meth)acrylate, (meth)acryloyl group-containing polybutadiene compound, etc.

[0051] [(Meth)acrylate]

[0052] As specific examples of the (meth)acrylate, the following can be cited: N-acryloyloxyethyl hexahydrophthalimide, acryloylmorpholine, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, cyclohexane-1,4-dimethanol mono(meth)acrylate, tetrahydrofurfuryl (meth)acrylate, phenoxyethyl (meth)acrylate, phenyl polyethoxy (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, o-phenylphenol monoethoxy (meth)acrylate, o-phenylphenol polyethoxy (meth)acrylate, p-cumylphenoxyethyl (meth)acrylate, isobornyl (meth)acrylate, tribromophenoxyethyl (meth)acrylate, tetrahydrodicyclopentadienyl (meth)acrylate, dicyclopentadienyl (meth)acrylate, dicyclopentadienyloxyethyl (meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, tricyclodecane dimethanol (meth)acrylate, bisphenol A polyethoxy di(meth)acrylate, bisphenol A polypropoxy di(meth)acrylate, bisphenol F polyethoxy di(meth)acrylate, ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, tris(acryloyloxyethyl) isocyanurate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, tripentaerythritol hexa(meth)acrylate, tripentaerythritol penta(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane polyethoxy tri(meth)acrylate, bis(trimethylolpropane) tetra(meth)acrylate, the diacrylate of the ester of neopentyl glycol and hydroxypivalic acid or the diacrylate of the ε-caprolactone adduct of the ester of neopentyl glycol and hydroxypivalic acid, and other monomeric compounds. Preferred examples include o-phenylphenol monoethoxy (meth)acrylate and o-phenylphenol polyethoxy (meth)acrylate.

[0053] [Epoxy (meth)acrylate]

[0054] Epoxy (meth)acrylate can be obtained by reacting an epoxy resin with (meth)acrylic acid using a known method. There is no particular limitation on the epoxy resin used as a raw material, but an epoxy resin having two or more functional groups is preferred. For example, examples thereof include dimer acid-modified epoxy resin, resorcinol diglycidyl ether, 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 epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, hydantoin type epoxy resin, isocyanurate type epoxy resin, phenol novolak type epoxy resin having a trihydroxyphenylmethane skeleton, and diglycidyl ether compounds of bifunctional phenols such as catechol and resorcinol, diglycidyl ether compounds of bifunctional alcohols, and their halides, hydrogenated products, and the like. Among them, from the viewpoint of liquid crystal contamination, bisphenol A type epoxy resin and resorcinol diglycidyl ether are preferred. In addition, there is no limitation on the ratio of the epoxy group to the (meth)acryloyl group, and it is appropriately selected from the viewpoint of process suitability.

[0055] It should be noted that a partially epoxy (meth)acrylate in which a part of the epoxy group is acrylated can be appropriately used. In this case, the acrylation ratio is preferably about 30% to about 70%.

[0056] [Urethane (meth)acrylate]

[0057] Urethane (meth)acrylate has a soft skeleton peculiar to the urethane structure, and thus the cured product has the characteristics of being soft and having low moisture permeability, and can also follow the bending of a flexible display. Therefore, it is preferably used as a curable compound, and a urethane (meth)acrylate having a polyester structure is more preferably used.

[0058] Urethane (meth)acrylate can be obtained by reacting (a) a polyol, (b) an organic polyisocyanate, and (c) a hydroxy group-containing (meth)acrylate and synthesizing by a conventional method, and a catalyst such as a tin compound is used as needed.

[0059] In the synthesis of urethane (meth)acrylate, relative to 1 equivalent of the hydroxyl group in the component (a), it is preferred to react 1.1 equivalents to 2.0 equivalents of the isocyanate group in the component (b), and it is particularly preferred to react 1.3 equivalents to 2.0 equivalents of the isocyanate group in the component (b). The reaction temperature is preferably room temperature (25 °C) to 100 °C.

[0060] Preferably, 0.95 to 1.1 equivalents of the hydroxyl groups in component (c) are reacted with respect to 1 equivalent of the isocyanate groups in the reaction product of component (a) and component (b). The reaction temperature is preferably from room temperature (25 °C) to 100 °C.

[0061] Specific examples of the polyol (a) include: tricyclodecane dimethanol, hydrogenated polybutadiene polyol, dimer diol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,14-tetradecanediol, 1,16-hexadecanediol, 1,18-octadecanediol, 1,20-eicosanediol, 1-methyl-1,8-octanediol, 2-methyl-1,8-octanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, cyclohexane-1,4-dimethanol, polyethylene glycol, polypropylene glycol, bisphenol A poly(n≈2 to 20) ethoxydiol, bisphenol A poly(n≈2 to 20) propoxydiol and other diols (a-1), and polyester polyols (a-2) which are reaction products of these diols (a-1) and dibasic acids or their acid anhydrides (such as succinic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, isophthalic acid, terephthalic acid, phthalic acid or their acid anhydrides). Polyester polyols and polyols having an aromatic ring are preferred, and polyester polyols having an aromatic ring are particularly preferred. Examples of the aromatic ring include: aromatic hydrocarbon rings such as benzene ring, naphthalene ring, anthracene ring, phenanthroline ring; aromatic heterocycles such as furan ring, pyrrole ring, thiophene ring, pyridine ring, thiazole ring, benzothiazole ring, and a benzene ring or a naphthalene ring is preferred.

[0062] Component (a) can be used alone or in combination of two or more.

[0063] Specific examples of the organic polyisocyanate (b) include: toluene diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, xylylene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, trimethylhexamethylene diisocyanate, dimer acid diisocyanate, 1,5-naphthalene diisocyanate, 3,3'-dimethyl-4,4'-diphenylene diisocyanate, etc. Preferred examples include: toluene diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate, trimethylhexamethylene diisocyanate.

[0064] As specific examples of the (meth)acrylate containing a hydroxyl group, the following can be mentioned: 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 1,4-butanediol (meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, pentaerythritol tri(meth)acrylate, ε-caprolactone adduct of 2-hydroxyethyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, etc. Preferred examples include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and polyethylene glycol mono(meth)acrylate.

[0065] The lower limit of the weight-average molecular weight in terms of polystyrene in the GPC of the urethane (meth)acrylate is preferably 1000 or more, more preferably 2000 or more, particularly preferably 3000 or more, and most preferably 4000 or more. In addition, the upper limit is preferably 10000 or less, more preferably 8000 or less, particularly preferably 7000 or less, and most preferably 6000 or less. When the weight-average molecular weight of the urethane (meth)acrylate is within the above range, while maintaining good flexibility and moisture permeability, the viscosity of the liquid crystal sealant is within an appropriate range.

[0066] [Polybutadiene compound having a (meth)acryloyl group]

[0067] As the polybutadiene compound having a (meth)acryloyl group, for example, it can be obtained on the market as TEAI-1000 and TE-2000 manufactured by Nippon Soda Co., Ltd. From the viewpoint of reducing liquid crystal contamination, the lower limit of the number-average molecular weight of these polybutadiene compounds is preferably 500, more preferably 750, and particularly preferably 1000. In addition, from the viewpoint of handleability, the upper limit of the number-average molecular weight of these polybutadiene compounds is preferably 10000, more preferably 8000, and particularly preferably 6000.

[0068] [Compound having a mercapto group]

[0069] As compounds having a mercapto group, examples include: methanedithiol, 1,2-dimercaptoethane, 1,2-dimercaptopropane, 2,2-dimercaptopropane, 1,3-dimercaptopropane, 1,2,3-trimercaptopropane, 1,4-dimercaptobutane, 1,6-dimercaptohexane, bis(2-mercaptoethyl)sulfide, 1,2-bis(2-mercaptoethylthio)ethane, 1,5-dimercapto-3-oxapentane, 1,8-dimercapto-3,6-dioxaoctane, 2,2-dimethylpropane-1,3-dithiol, 3,4-dimethoxybutane-1,2-dithiol, 2-mercaptomethyl-1,3-dimercaptopropane, 2-mercaptomethyl-1,4-dimercaptobutane, 2-(2-mercaptoethylthio)-1,3-dimercaptopropane, 1,2-bis(2-mercaptoethylthio)-3-mercaptopropane, 1,1,1-tris(mercaptomethyl)propane, tetrakis(mercaptomethyl)methane, ethylene glycol bis(2-mercaptoacetate), ethylene glycol bis(3-mercaptopropionate), 1,4-butanediol bis(2-mercaptoacetate), 1,4-butanediol bis(3-mercaptopropionate), trimethylolpropane tris(2-mercaptoacetate), trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(2-mercaptoacetate), pentaerythritol tetrakis(3-mercaptopropionate), 1,1-dimercaptocyclohexane, 1,4-dimercaptocyclohexane, 1,3-dimercaptocyclohexane, 1,2-dimercaptocyclohexane, dipentaerythritol hexa(3-mercaptopropionate), dipentaerythritol hexa(2-mercaptoacetate), 1,2-dimercaptobenzene, 1,3-dimercapto-2-propanol, 2,3-dimercapto-1-propanol, 1,2-dimercapto-1,3-butanediol, hydroxymethyl-tris(mercaptoethylthiomethyl)methane, hydroxyethylthiomethyl-tris(mercaptoethylthio)methane, ethylene glycol bis(3-mercaptopropionate), propylene glycol bis(3-mercaptopropionate), butanediol bis(3-mercaptopropionate), octanediol bis(3-mercaptopropionate), tetraethylene glycol bis(3-mercaptopropionate), ethylene glycol bis(4-mercaptobutyrate), propylene glycol bis(4-mercaptobutyrate), butanediol bis(4-mercaptobutyrate), octanediol bis(4-mercaptobutyrate), trimethylolpropane tris(4-mercaptobutyrate), pentaerythritol tetrakis(4-mercaptobutyrate), ethylene glycol bis(5-mercaptovalerate), propylene glycol bis(5-mercaptovalerate), butanediol bis(5-mercaptovalerate), octanediol bis(5-mercaptovalerate), trimethylolpropane tris(5-mercaptovalerate), pentaerythritol tetrakis(5-mercaptovalerate), 1,6-hexanedithiol, 1,9-nonanedithiol, 1,10-decanedithiol, 4,4'-bis(mercaptomethyl)phenyl sulfide, 2,4'-bis(mercaptomethyl)phenyl sulfide, 2,4,4'-tris(mercaptomethyl)phenyl sulfide, 2,2',4,4'-tetrakis(mercaptomethyl)phenyl sulfide, 1,3,5-tris[2-(3-mercaptopropionyloxy)ethyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,3,5-Tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, pentaerythritol tetra(3-mercaptobutyrate), 1,4-bis(3-mercaptobutyryloxy)butane, etc. These substances can be used alone or in combination of two or more of them.

[0070] Among them, trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetra(3-mercaptopropionate), dipentaerythritol hexa(3-mercaptopropionate), 1,3,5-tris[2-(3-mercaptopropionyloxy)ethyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, and pentaerythritol tetra(3-mercaptobutyrate) are preferred. From the viewpoints of liquid crystal contamination and storage stability at room temperature, 1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione and pentaerythritol tetra(3-mercaptobutyrate) having a secondary thiol structure are further particularly preferred.

[0071] These compounds having a mercapto group can be produced by known methods or commercially available compounds can be used. Examples of commercially available compounds include: Karenz MT RTM PE1, BD1, NR1, trimethylolpropane tris(3-mercaptobutyrate), trimethylolethane tris(3-mercaptobutyrate) (all manufactured by Resonac Co., Ltd.), Polythiol RTM 340M (manufactured by Toray Fine Chemical Co., Ltd.), pentaerythritol tetra(3-mercaptopropionate) (manufactured by SC Organic Chemistry Co., Ltd.), etc.

[0072] In addition, compounds having three or more functional mercapto groups in the molecule are also preferred. Examples include: 2,4,4'-tris(mercaptomethyl)phenyl sulfide, 2,2',4,4'-tetrakis(mercaptomethyl)phenyl sulfide, 1,3,5-tris[2-(3-mercaptopropionyloxy)ethyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, pentaerythritol tetra(3-mercaptobutyrate), 1,4-bis(3-mercaptobutyryloxy)butane, etc. This is because by increasing the crosslinking density, heat resistance and the like can be improved. In addition, especially when used in a liquid crystal display unit, elution into the liquid crystal can be suppressed and high reliability can be achieved.

[0073] [Compound having an epoxy group]

[0074] Examples of the compound having an epoxy group include epoxy resins, polybutadiene compounds having an epoxy group, and the like.

[0075] [Epoxy resin]

[0076] The epoxy resin is not particularly limited, but a difunctional or higher-functional epoxy resin is preferred. Examples thereof include dimer acid-modified epoxy resins, resorcinol diglycidyl ether, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, bisphenol A novolac-type epoxy resins, bisphenol F novolac-type epoxy resins, alicyclic epoxy resins, aliphatic chain epoxy resins, glycidyl ester-type epoxy resins, glycidyl amine-type epoxy resins, hydantoin-type epoxy resins, isocyanurate-type epoxy resins, phenol novolac-type epoxy resins having a trihydroxyphenylmethane skeleton, and diglycidyl ether compounds of difunctional phenols such as catechol and resorcinol, diglycidyl ether compounds of difunctional alcohols, and their halides, hydrogenated products, and the like. Among them, from the viewpoint of liquid crystal contamination, bisphenol A-type epoxy resins and resorcinol diglycidyl ether are preferred.

[0077] [Polybutadiene compound having an epoxy group]

[0078] Examples of the polybutadiene compound having an epoxy group can be obtained on the market as JP-100 and JP-200 manufactured by Nippon Soda Co., Ltd. From the viewpoint of reducing liquid crystal contamination, the lower limit of the number average molecular weight of these polybutadiene compounds is preferably 500, more preferably 750, and particularly preferably 1000. In addition, from the viewpoint of processability, the upper limit of the number average molecular weight of these polybutadiene compounds is preferably 10,000, more preferably 8000, and particularly preferably 6000.

[0079] Component (B) can use the above materials alone or mix two or more of the above materials. In 100 parts by weight of the total amount of the liquid crystal sealant, component (B) is preferably 78 parts by weight or more and 90 parts by weight or less, more preferably 80 parts by weight or more and 86 parts by weight or less.

[0080] [(C) Photo radical polymerization initiator]

[0081] The liquid crystal sealant of the present invention may contain a photo radical polymerization initiator (hereinafter also simply referred to as "component (C)") as component (C). As the photo radical polymerization initiator, there is no particular limitation as long as it is a compound that generates radicals and acids upon irradiation with ultraviolet rays or visible light and initiates a chain polymerization reaction. For example, it can include: benzoyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, diethyl thioxanthone, benzophenone, 2-ethyl anthraquinone, 2-hydroxy-2-methylpropiophenone, 2-methyl-[4-(methylthio)phenyl]-2-morpholin-1-one, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, camphorquinone, 9-fluorenone, diphenyl disulfide, etc. Specifically, it can include: IRGACURE RTM 651, 184, 2959, 127, 907, 369, 379EG, 819, 784, 754, 500, OXE01, OXE02, OXE03, OXE04, DAROCURE RTM 1173, LUCIRIN RTM TPO (all manufactured by BASF), SEIKUOL RTM Z, BZ, BEE, BIP, BBI (all manufactured by Seiko Chemical Co., Ltd.), KAYACURE DETX-S (manufactured by Nippon Kayaku Co., Ltd.), etc. Among them, preferably IRGACURE RTM OXE01, OXE02, OXE03, OXE04 and KAYACURE DETX-S as thioxanthone initiators.

[0082] In addition, by using an oxime ester initiator and a thioxanthone initiator in combination, it is possible to balance rapid curability and curability in the light-shielded part, and it can be cured even by visible light, so it is preferred.

[0083] In the liquid crystal sealant of the present invention, when component (C) is used, in 100 parts by weight of the total amount of the liquid crystal sealant, component (C) is usually 0.001 part by weight to 3 parts by weight, preferably 0.01 part by weight to 2 parts by weight.

[0084] [(D) Thermal curing agent]

[0085] The liquid crystal sealant of the present invention can achieve improved reactivity by adding a thermal curing agent (hereinafter also simply referred to as "component (D)") as component (D).

[0086] As the component (D), for example, the following can be listed: compounds having a carboxyl group bonded to an aromatic ring in the molecule, polyamines, polyphenols, organic acid hydrazides, imidazole compounds, etc. However, it is not limited to these substances. For example, the following can be listed: terephthalic dihydrazide, isophthalic dihydrazide, 2,6-naphthalenedicarboxylic dihydrazide, 2,6-pyridinedicarboxylic dihydrazide, 1,2,4-benzenetricarboxylic trihydrazide, 1,4,5,8-naphthalenetetracarboxylic tetrahydrazide, pyromellitic tetrahydrazide, etc. as aromatic hydrazides. In addition, if it is an aliphatic hydrazide, for example, formyl hydrazide, acetyl hydrazide, propionyl hydrazide, oxalic dihydrazide, malonic dihydrazide, succinic dihydrazide, glutaric dihydrazide, adipic dihydrazide, pimelic dihydrazide, sebacic dihydrazide, 1,4-cyclohexanedicarboxylic dihydrazide, tartaric dihydrazide, malic dihydrazide, iminodiacetic dihydrazide, N,N'-hexamethylenebisaminourea, citric trihydrazide, nitrilotriacetic trihydrazide, cyclohexanetricarboxylic trihydrazide, 1,3-bis(hydrazinocarbonylethyl)-5-isopropylhydantoin and other dihydrazides having a hydantoin skeleton, preferably a valine hydantoin skeleton (a skeleton in which the carbon atom of the hydantoin ring is substituted by an isopropyl group), tris(1-hydrazinocarbonylmethyl)isocyanurate, tris(2-hydrazinocarbonylethyl)isocyanurate, tris(1-hydrazinocarbonylethyl)isocyanurate, tris(3-hydrazinocarbonylpropyl)isocyanurate, bis(2-hydrazinocarbonylethyl)isocyanurate, etc. In addition, as imidazole compounds, 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 2,4-diamino-6-(2'-methylimidazol(1'))ethyl-s-triazine, 2,4-diamino-6-(2'-undecylimidazol(1'))ethyl-s-triazine, 2,4-diamino-6-(2'-ethyl-4-methylimidazol(1'))ethyl-s-triazine, 2,4-diamino-6-(2'-methylimidazol(1'))ethyl-s-triazine·isocyanuric acid adduct, 2:3 adduct of 2-methylimidazole·isocyanuric acid, 2-phenylimidazole·isocyanuric acid adduct, 2-phenyl-3,5-dihydroxymethylimidazole, 2-phenyl-4-hydroxymethyl-5-methylimidazole, 1-cyanoethyl-2-phenyl-3,5-bis(cyanoethoxymethyl)imidazole, etc. From the viewpoint of the balance between curing reactivity and latency, isophthalic dihydrazide, malonic dihydrazide, adipic dihydrazide, tris(1-hydrazinocarbonylmethyl)isocyanurate, tris(1-hydrazinocarbonylethyl)isocyanurate, tris(2-hydrazinocarbonylethyl)isocyanurate, tris(3-hydrazinocarbonylpropyl)isocyanurate, 2,4-diamino-6(2'-methylimidazol(1'))ethyl-s-triazine·isocyanuric acid adduct are preferred.

[0087] Component (D) can be used alone or two or more thereof can be mixed. Relative to 100 parts by weight of the component (B), it is preferred to add 0.5 parts by weight or more and 15.0 parts by weight or less of component (D), more preferably 0.7 parts by weight or more and 10 parts by weight or less of component (D), and particularly preferably 2.0 parts by weight or more and 8.0 parts by weight or less of component (D).

[0088] In addition, for component (D), it is preferred to reduce the particle size using a jet mill or the like. Specifically, the average particle size is preferably 3.0 μm or less, more preferably 2.5 μm or less, and particularly preferably 2.0 μm or less.

[0089] [(E) Thermal free radical polymerization initiator]

[0090] The liquid crystal sealant of the present invention can improve the curing rate and curability by containing (E) a thermal free radical polymerization initiator (hereinafter also simply referred to as "component (E)").

[0091] Component (E) is not particularly limited as long as it is a compound that generates free radicals by heating and initiates a chain polymerization reaction. Examples include: organic peroxides, azo compounds, benzoin compounds, benzoin ether compounds, acetophenone compounds, benzoin pinacol, etc. Benzoin pinacol is preferably used. For example, as organic peroxides, Kayamek RTM A, M, R, L, LH, SP-30C; Perkadox CH-50L, BC-FF; Cadox B-40ES; Perkadox 14; Trigonox RTM 22-70E, 23-C70, 121, 121-50E, 121-LS50E, 21-LS50E, 42, 42LS; Kayaester RTM P-70, TMPO-70, CND-C70, OO-50E, AN; Kayabutyl RTM B; Perkadox 16; Kayacarbon RTM BIC-75, AIC-75 (manufactured by Nippon Kayaku AKZO Co., Ltd.); Permek RTM N, H, S, F, D, G; Perhexa RTM H, HC, TMH, C, V, 22, MC; Percure RTM AH, AL, HB; Perbutyl RTM H, C, ND, L; Percumyl RTM H, D; Peroyl RTM IB, IPP; PeroctaRTM ND (manufactured by NOF Corporation) etc.

[0092] In addition, as azo compounds, VA-044, 086, V-070, VPE-0201, VSP-1001 (manufactured by Fujifilm Wako Pure Chemical Corporation) etc. can be obtained as commercially available products.

[0093] The preferred substance for component (E) is a thermal free radical polymerization initiator that does not have an oxygen-oxygen bond (-O-O-) and a nitrogen-nitrogen bond (-N=N-) in the molecule. A thermal free radical polymerization initiator having an oxygen-oxygen bond (-O-O-) or a nitrogen-nitrogen bond (-N=N-) in the molecule generates a large amount of oxygen or nitrogen when generating free radicals, so it cures in a state where bubbles remain in the liquid crystal sealant, which may cause a decrease in adhesive strength, a decrease in moisture permeability, a decrease in characteristics under a humid heat environment, etc. A thermal free radical polymerization initiator of benzoin type (including substances obtained by chemically modifying benzoin) is particularly preferred. Specifically, benzoin, 1,2-dimethoxy-1,1,2,2-tetraphenylethane, 1,2-diethoxy-1,1,2,2-tetraphenylethane, 1,2-diphenoxy-1,1,2,2-tetraphenylethane, 1,2-dimethoxy-1,1,2,2-tetrakis(4-methylphenyl)ethane, 1,2-diphenoxy-1,1,2,2-tetrakis(4-methoxyphenyl)ethane, 1,2-bis(trimethylsilyloxy)-1,1,2,2-tetraphenylethane, 1,2-bis(triethylsilyloxy)-1,1,2,2-tetraphenylethane, 1,2-bis(tert-butyldimethylsilyloxy)-1,1,2,2-tetraphenylethane, 1-hydroxy-2-trimethylsilyloxy-1,1,2,2-tetraphenylethane, 1-hydroxy-2-triethylsilyloxy-1,1,2,2-tetraphenylethane, 1-hydroxy-2-tert-butyldimethylsilyloxy-1,1,2,2-tetraphenylethane etc. can be cited, and 1-hydroxy-2-trimethylsilyloxy-1,1,2,2-tetraphenylethane, 1-hydroxy-2-triethylsilyloxy-1,1,2,2-tetraphenylethane, 1-hydroxy-2-tert-butyldimethylsilyloxy-1,1,2,2-tetraphenylethane, 1,2-bis(trimethylsilyloxy)-1,1,2,2-tetraphenylethane are preferred, 1-hydroxy-2-trimethylsilyloxy-1,1,2,2-tetraphenylethane, 1,2-bis(trimethylsilyloxy)-1,1,2,2-tetraphenylethane are further preferred, and 1,2-bis(trimethylsilyloxy)-1,1,2,2-tetraphenylethane is particularly preferred.

[0094] The above-mentioned benzoin is sold by companies such as Tokyo Chemical Industry Co., Ltd. and FUJIFILM Wako Pure Chemical Corporation. In addition, etherification of the hydroxyl group of benzoin can be easily synthesized by a known method. Further, silylation of the hydroxyl group of benzoin can be synthesized by heating the corresponding benzoin with various silylating agents in the presence of a basic catalyst such as pyridine. Examples of silylating agents include trimethylchlorosilane (TMCS), hexamethyldisilazane (HMDS), N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), which are commonly known as trimethylsilylating agents, triethylchlorosilane (TECS) as a triethylsilylating agent, and tert-butyldimethylsilane (TBMS) as a tert-butyldimethylsilylating agent. These reagents can be easily obtained from the market, such as from silicon derivative manufacturers. The reaction amount of the silylating agent is preferably 1.0 to 5.0 times the molar amount, more preferably 1.5 to 3.0 times the molar amount, relative to 1 mole of the hydroxyl group in the target compound. When the reaction amount of the silylating agent is less than 1.0 times the molar amount, the reaction efficiency is poor and the reaction time becomes long, thus promoting thermal decomposition. When the reaction amount of the silylating agent is greater than 5.0 times the molar amount, separation during recovery becomes poor or purification becomes difficult.

[0095] In 100 parts by weight of the total amount of the liquid crystal sealant of the present invention, the content of component (E) is preferably 0.0001 to 5 parts by weight, more preferably 0.0005 to 3 parts by weight, and particularly preferably 0.001 to 1 part by weight.

[0096] [(O) Other components]

[0097] In the liquid crystal sealant of the present invention, additives such as a curing accelerator, a silane coupling agent, a radical polymerization inhibitor, a pigment, a leveling agent, an antifoaming agent, and a solvent can be further added as needed.

[0098] [Curing accelerator]

[0099] The liquid crystal sealant of the present invention can further improve the reactivity by adding a curing accelerator. Examples of the curing accelerator include organic acids.

[0100] Examples of organic acids include organic carboxylic acids and organic phosphoric acids, and preferably organic carboxylic acids. Specifically, examples include aromatic carboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, benzophenone tetracarboxylic acid, and furandicarboxylic acid, and aliphatic carboxylic acids such as succinic acid, adipic acid, dodecanedioic acid, sebacic acid, thiodipropionic acid, cyclohexanedicarboxylic acid, tris(carboxymethyl)isocyanurate, tris(2-carboxyethyl)isocyanurate, tris(2-carboxypropyl)isocyanurate, and bis(2-carboxyethyl)isocyanurate.

[0101] When a curing accelerator is used in the liquid crystal sealant of the present invention, in 100 parts by weight of the total amount of the liquid crystal sealant, the content of the curing accelerator is preferably 0.1 part by weight to 10 parts by weight, and more preferably 1 part by weight to 5 parts by weight.

[0102] [Silane coupling agent]

[0103] Examples of the silane coupling agent include: 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, N-(2-(vinylbenzylamino)ethyl)-3-aminopropyltrimethoxysilane hydrochloride, 3-methacryloxypropyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, etc. These silane coupling agents are sold by Shin-Etsu Chemical Co., Ltd. under the KBM series, KBE series, etc., and thus can be easily obtained from the market. When a silane coupling agent is used in the liquid crystal sealant of the present invention, in 100 parts by weight of the total amount of the liquid crystal sealant, the content of the silane coupling agent is preferably 0.05 part by weight to 3 parts by weight.

[0104] [Free radical polymerization inhibitor]

[0105] As the above radical polymerization inhibitor, as long as it is a compound that inhibits polymerization by reacting with radicals generated by a photo radical polymerization initiator, a thermal radical polymerization initiator, etc., there is no particular limitation, and quinones, piperidines, hindered phenols, nitroso compounds, etc. can be used. Specifically, examples include: naphthoquinone, 2-hydroxynaphthoquinone, 2-methylnaphthoquinone, 2-methoxynaphthoquinone, 2,2,6,6-tetramethylpiperidin-1-oxyl, 2,2,6,6-tetramethyl-4-hydroxypiperidin-1-oxyl, 2,2,6,6-tetramethyl-4-methoxypiperidin-1-oxyl, 2,2,6,6-tetramethyl-4-phenoxypiperidin-1-oxyl, hydroquinone, 2-methylhydroquinone, 2-methoxyhydroquinone, p-benzoquinone, butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-p-cresol, stearyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), 3,9-bis[1,1-dimethyl-2-[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, tetra[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyhydrocinnamate)methane], 1,3,5-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)-s-triazine-2,4,6-(1H,3H,5H)trione, p-methoxyphenol, 4-methoxy-1-naphthol, thiodiphenylamine, aluminum salt of N-nitrosophenylhydroxylamine, trade name ADK STAB LA-81, trade name ADK STAB LA-82 (manufactured by Adeka Corporation), etc., but are not limited to these substances. Among them, radical polymerization inhibitors of naphthoquinones, hydroquinones, nitroso compounds, and piperidines are preferred, and naphthoquinone, 2-hydroxynaphthoquinone, hydroquinone, 2,6-di-tert-butyl-p-cresol, POLYSTOP 7300P (manufactured by Pfeiffer Vacuum Technology Co., Ltd.) are further preferred, and POLYSTOP 7300P (manufactured by Pfeiffer Vacuum Technology Co., Ltd.) is most preferred.

[0106] As the content of the radical polymerization inhibitor, in 100 parts by weight of the total amount of the liquid crystal sealant of the present invention, it is preferably 0.0001 part by weight to 1 part by weight, more preferably 0.001 part by weight to 0.5 part by weight, and particularly preferably 0.005 part by weight to 0.2 part by weight.

[0107] As an example of a method for obtaining the liquid crystal sealant of the present invention, the method shown below can be cited. First, the curable compound, the photoradical initiator, the thermal radical polymerization initiator, and the radical polymerization inhibitor are heated and dissolved at 90°C, then cooled to room temperature, and a silane coupling agent, a curing agent, a curing accelerator, a filler, a defoaming agent, a leveling agent, and a solvent are added, and uniformly mixed using a known mixing device such as a three-roll mill, a sand mill, a ball mill, etc., and filtered using a metal mesh, thereby being able to manufacture the liquid crystal sealant of the present invention.

[0108] The liquid crystal display unit manufactured using the liquid crystal sealant of the present invention is obtained by the following method: a pair of substrates having predetermined electrodes formed on the substrates are arranged relative to each other at a predetermined interval, the surroundings are sealed with the liquid crystal sealant of the present invention, and liquid crystal is sealed in the gap. The type of liquid crystal to be sealed is not particularly limited. Here, the substrate is composed of a composite substrate containing glass, quartz, plastic, silicon, etc., at least one of which is light-transmissive. As a manufacturing method, a spacer such as glass fiber (gap control material) is added to the liquid crystal sealant of the present invention, and then the liquid crystal sealant is applied to one of the pair of substrates using a dispenser or a screen printing device, and then pre-cured at 80°C to 120°C as needed. Then, liquid crystal is dripped on the inner side of the cofferdam of the liquid crystal sealant, and another glass substrate is overlapped in a vacuum to form a gap. After the gap is formed, it is cured at 90°C to 130°C for 30 minutes to 2 hours, thereby obtaining the liquid crystal display unit of the present invention. In addition, when used in the form of a light-heat combined type, light curing is performed by irradiating ultraviolet rays to the liquid crystal sealant using an ultraviolet irradiator. The UV irradiation dose is preferably 500mJ / cm 2 ~6000mJ / cm 2 , more preferably 1000mJ / cm 2 ~4000mJ / cm 2 (measurement wavelength: 365nm) irradiation amount. Then, curing is performed at 90°C to 130°C for 30 minutes to 2 hours as needed, thereby obtaining the liquid crystal display unit of the present invention. The liquid crystal display unit of the present invention obtained in this way does not have poor display caused by liquid crystal contamination, and has excellent adhesion and moisture resistance reliability. As spacers, for example, glass fibers, silica microbeads, polymer microbeads, etc. The diameter of the spacer varies depending on the purpose, and is usually 2μm to 8μm, preferably 4μm to 7μm. Relative to 100 parts by weight of the liquid crystal sealant of the present invention, the amount of the spacer used is usually about 0.1 parts by weight to about 4 parts by weight, preferably about 0.5 parts by weight to about 2 parts by weight, and more preferably about 0.9 parts by weight to about 1.5 parts by weight.

[0109] Example

[0110] Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the examples. It should be noted that unless otherwise specified, "parts" and "%" in this specification are based on weight.

[0111] [Synthesis Example 1]

[0112] 776.99 g of a polyester polyol of methylpentanediol, adipic acid and isophthalic acid (manufactured by Kuraray Co., Ltd., P-2012, hydroxyl value 54.6 mgKOH / g) and 131.68 g of tolylene diisocyanate (manufactured by Tosoh Corporation, Coronate T-100, molecular weight 174.2) were put into a flask equipped with a thermometer, a condenser and a stirring device, and reacted at 80°C. The isocyanate content at this time was determined by adding an excessive amount of amine and performing back-titration with hydrochloric acid, and it was confirmed that the value was within the range of plus or minus 2% of the residual amount of isocyanate calculated from the calculated value. Then, 0.6 g of p-methoxyphenol (polymerization inhibitor), 90.43 g of 2-hydroxyethyl acrylate (molecular weight 116.1), and 0.3 g of dibutyltin dilaurate (catalyst) were added, and stirring was carried out at 80°C until the absorption spectrum of the isocyanate group (2280 cm -1 ) disappeared in the infrared absorption spectrum, thereby obtaining a urethane acrylate oligomer having a weight average molecular weight of 6300.

[0113] [Synthesis Example 2]

[0114] 100 parts (0.28 mol) of commercially available benzoin (manufactured by Tokyo Chemical Industry) was dissolved in 350 parts of dimethylformamide. 32 parts (0.4 mol) of pyridine as a basic catalyst and 150 parts (0.58 mol) of BSTFA as a silylating agent (manufactured by Shin-Etsu Chemical Co., Ltd.) were added thereto, and the temperature was raised to 70°C and stirred for 2 hours. The obtained reaction solution was cooled, and 200 parts of water was added while stirring to precipitate the product and deactivate the unreacted silylating agent at the same time. The precipitated product was separated by filtration and then washed thoroughly with water. Then, the obtained product was dissolved in acetone, and recrystallized and purified by adding water. 105.6 parts (yield 88.3%) of 1,2-bis(trimethylsilyloxy)-1,1,2,2-tetraphenylethane as the target product was obtained.

[0115] [Examples 1 to 20, Comparative Examples 1 to 4]

[0116] The curable compound, photo radical initiator, and radical polymerization inhibitor were heated and dissolved at 90°C in the proportions shown in Table 1 and Table 2 below, then cooled to room temperature, and a silane coupling agent, curing agent, curing accelerator, filler, and thermal radical polymerization initiator were added and stirred. Then, it was dispersed using a three-roll mill and filtered through a metal mesh (635 mesh) to prepare a liquid crystal sealant.

[0117] [Evaluation]

[0118] [Viscosity][Thixotropy ratio]

[0119] For the liquid crystal sealants manufactured in the examples and comparative examples, the viscosity was measured using an R-type viscometer (R115U type viscometer: manufactured by Toki Sangyo Co., Ltd.) under the conditions of a measuring cone of 3°×R7.7, rotation speeds of 5 rpm and 0.5 rpm, and an atmosphere of 25°C. The thixotropy ratio was calculated using the formula of viscosity at 0.5 rpm / viscosity at 5 rpm. The results are shown in Table 1 and Table 2.

[0120] [Elastic modulus]

[0121] The liquid crystal sealants manufactured in the examples and comparative examples were sandwiched between polyethylene terephthalate (PET) films to form a film with a thickness of 100 μm, and this film was irradiated with ultraviolet light of 3000 mJ / cm 2 (measurement wavelength: 365 nm) using a UV irradiator, then placed in an oven and thermally cured at 120°C for 70 minutes. After curing, the PET film was peeled off to prepare a sample. A tensile test was performed on the sample using a Tensilon universal testing machine (manufactured by A&D Company, Ltd., RTG-1210) at room temperature (25°C) at a test speed of 5 mm / minute for measurement. The results are shown in Table 1 and Table 2.

[0122] [Moisture permeability]

[0123] The liquid crystal sealants manufactured in the examples and comparative examples were sandwiched between polyethylene terephthalate (PET) films to form a film with a thickness of 300 μm, and this film was irradiated with ultraviolet light of 3000 mJ / cm 2 (measurement wavelength: 365 nm) using a UV irradiator, then placed in an oven and thermally cured at 120°C for 70 minutes. After curing, the PET film was peeled off to prepare a sample. The moisture permeability of the sample was measured at 60°C and 90% using a moisture permeability measuring instrument (manufactured by Lyssy Co., Ltd.: L80-5000). The results are shown in Table 1 and Table 2.

[0124] [Shear adhesive strength]

[0125] An alignment film solution (manufactured by JSR Corporation: Optmer AL19801-R8) was spin-coated on a glass substrate, pre-baked on a hot plate at 110 °C for 2 minutes, and baked in an oven at 230 °C for 20 minutes to obtain an alignment film substrate. 1 wt% of 4-μm glass fibers as spacers was added to the liquid crystal sealants prepared in the examples and comparative examples, and mixing and stirring were carried out using a planetary stirring device (manufactured by EME Corporation: VMX-360). The fabricated alignment film substrate was cut into a rectangle of 25 mm × 45 mm. As shown in Figure 1 , the prepared sealant was applied to the central part where two substrates overlapped, and the substrates were temporarily fixed and bonded using a jig. Ultraviolet rays with 3000 mJ / cm 2 (measurement wavelength: 365 nm) were irradiated using a UV irradiator, and then heat curing was carried out at 120 °C for 70 minutes for adhesion. A tensile test was performed on the obtained bonded substrate at room temperature (25 °C) using a Tensilon universal testing machine (manufactured by A&D Company, Limited, RTG-1210) at a test speed of 1000 mm / min, and the maximum load at the time of substrate peeling was measured. The shear adhesion strength was obtained by dividing the maximum load at the time of peeling by the area of the sealant. The results are shown in Tables 1 and 2.

[0126] [Peeling Adhesion Strength]

[0127] An alignment film solution (manufactured by JSR Corporation: Optmer AL19801-R8) was spin-coated on a glass substrate, pre-baked on a hot plate at 110 °C for 2 minutes, and baked in an oven at 230 °C for 20 minutes to obtain an alignment film substrate. 1 wt% of 4-μm glass fibers as spacers was added to the liquid crystal sealants prepared in the examples and comparative examples, and mixing and stirring were carried out using a planetary stirring device (manufactured by EME Corporation: VMX-360). The prepared liquid crystal sealant was applied to the fabricated photo-alignment film substrate in a form that reproduced a corner with R = 0.5 mm and a length of 1 cm × 1 cm, with a seal width of 0.6 mm. The opposing photo-alignment film substrates were bonded in a vacuum of 1 Pa to 10 Pa and exposed to the atmosphere, and then ultraviolet rays with 3000 mJ / cm 2 (measurement wavelength: 365 nm) were irradiated using a UV irradiator, and then heat curing was carried out in a forced-air oven at 120 °C for 70 minutes for adhesion. The obtained bonded substrate was cut into the shape shown in Figure 2The shape of the lower substrate protruding only from the terminal portion envisioned as a display is pressed against the lower substrate at a position 4 mm apart on the diagonal of the corner of the applied display sealant using a universal testing machine (manufactured by Shimadzu Corporation: Autograph AG-Xplus500N) with a needle-shaped terminal of 3 mmφ, and the maximum load at the time of peeling the bonded substrate is measured, thereby obtaining the peel adhesion strength. The results are shown in Tables 1 and 2.

[0128] Table 1

[0129]

[0130] Table 2

[0131]

[0132]

[0133] From the results of Tables 1 and 2, it was confirmed that the moisture barrier property of the liquid crystal sealant of the present invention is excellent, and it has excellent adhesiveness to stresses in both the shear direction and the peel direction.

Claims

1. A liquid crystal sealant for a liquid crystal dropping method, comprising a filler having an average particle size of 0.4 μm or less as component (A), a curable compound as component (B), a photoradical polymerization initiator as component (C), and a thermosetting agent as component (D), wherein: The content of the component (A) is 7 parts by weight or more and 25 parts by weight or less relative to 100 parts by weight of the component (B), The liquid crystal sealing agent for a liquid crystal dropping method contains (B-1) a compound having a (meth)acryloyl group and (B-2) a compound having a mercapto group as the component (B). The elastic modulus of the cured product of the liquid crystal sealing agent for a liquid crystal dropping method at 25° C. measured with a universal testing machine is 2000 MPa or more and less than 4500 MPa.

2. The liquid crystal sealing agent for a liquid crystal dropping method according to claim 1, wherein The moisture permeability of the cured product of the liquid crystal sealant for a liquid crystal dropping method measured under the conditions of 60° C. and 90% was 50 g / m 2 Less than 24 hours.

3. The liquid crystal sealing agent for a liquid crystal dropping method according to claim 1, wherein The liquid crystal sealing agent for a liquid crystal dropping method contains a part of epoxy (meth)acrylate as the component (B-1).

4. The liquid crystal sealing agent for a liquid crystal dropping method according to claim 3, wherein The liquid crystal sealing agent for liquid crystal dropping methods contains urethane (meth)acrylate as the component (B-1).

5. The liquid crystal sealing agent for a liquid crystal dropping method according to claim 1, wherein The liquid crystal sealing agent for a liquid crystal dropping method further contains a component (E) a thermal radical polymerization initiator.

6. The liquid crystal sealing agent for a liquid crystal dropping method according to claim 5, wherein The component (E) is a thermal radical polymerization initiator that does not contain an oxygen-oxygen bond (-OO-) and a nitrogen-nitrogen bond (-N=N-) in the molecule.

7. A liquid crystal display panel, wherein: The liquid crystal display panel is sealed with the liquid crystal sealing agent according to any one of claims 1 to 6 by the liquid crystal dropping method.

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