Liquid crystal droplet injection method using liquid crystal sealant

Abstract

The present invention relates to a liquid crystal sealing agent for liquid crystal drop casting. The present invention provides a liquid crystal sealing agent for liquid crystal drop casting which has both transparency and high adhesion, which has been considered difficult to achieve, and a liquid crystal display unit sealed with a cured product thereof. A liquid crystal sealing agent for liquid crystal drop casting, which contains a curable compound, a filler, and a thermal curing agent, wherein the primary particle diameter of the filler is 0.3 μm or less, the content of the filler is 5 parts by mass or less with respect to 100 parts by mass of the curable compound, and the haze value of a cured product of the liquid crystal sealing agent for liquid crystal drop casting is 60% or less when the film thickness is 100 μm.

Description

Technical Field

[0001] This invention relates to a liquid crystal sealant for liquid crystal droplet injection and a liquid crystal display unit encapsulated using its cured form. Background Technology

[0002] In recent years, there has been development of transparent displays, and attempts have been made to enable transparent materials such as car windshields, shop windows, and partitions to function as displays (Patent Document 1). Among these, compared with organic electroluminescent (EL) displays and other displays, liquid crystal displays have fewer circuits per pixel, thus enabling them to achieve high transparency.

[0003] However, liquid crystal sealants typically appear white due to light scattering caused by the solid fillers they contain, thus posing a problem where liquid crystal sealants can damage the appearance of liquid crystal displays.

[0004] To improve the transparency of liquid crystal sealants, it is necessary to reduce the amount of solid fillers that are the main cause of scattering. However, when reducing fillers, the adhesive strength of liquid crystal sealants to the substrate is reduced, resulting in the problem of liquid crystal sealants peeling off due to external stress and impact.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2020-016710 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] The purpose of this invention is to provide a liquid crystal sealant for liquid crystal droplet method that is both transparent and highly adhesive, which was previously considered difficult to achieve, and a liquid crystal display unit sealed using its cured product.

[0010] means for solving problems

[0011] Through in-depth research, the inventors discovered that a specific liquid crystal sealant for liquid crystal dispensing methods possesses both transparency and high adhesiveness, thus completing this invention.

[0012] It should be noted that in this specification, "(meth)acrylate" refers to "acrylate" and / or "methacrylate".

[0013] That is, the present invention relates to the following [1] to [6]. [1]

[0015] A liquid crystal sealant for liquid crystal dispensing, comprising a curing compound, a filler, and a thermosetting agent, wherein...

[0016] The primary particle size of the filler is less than 0.3 μm.

[0017] The filler content is less than 5 parts by mass relative to 100 parts by mass of the curable compound, and

[0018] The haze value of the cured liquid crystal sealant used in the liquid crystal droplet method is less than 60% when the film thickness is 100 μm. [2]

[0020] As described in the preceding item [1], the liquid crystal sealant for liquid crystal droplet method, wherein the elastic modulus of the cured liquid crystal sealant for liquid crystal droplet method at 25°C, as determined by a universal testing machine, is less than 2000 MPa. [3]

[0022] Liquid crystal sealant for liquid crystal dispensing as described in [1] or [2] above, wherein the liquid crystal sealant for liquid crystal dispensing contains urethane (meth)acrylate as the curing compound. [4]

[0024] The liquid crystal sealant for liquid crystal droplet method as described in the preceding item [3], wherein the urethane (meth)acrylate is obtained by reacting (a) a polyol having an aromatic ring, (b) an organic polyisocyanate and (c) a hydroxyl-containing (meth)acrylate. [5]

[0026] The liquid crystal sealant for liquid crystal dispensing as described in any one of the preceding items [1] to [4], wherein the liquid crystal sealant for liquid crystal dispensing is a sealant for transparent liquid crystal displays. [6]

[0028] A liquid crystal display unit, wherein the liquid crystal display unit is encapsulated with a liquid crystal sealant using the liquid crystal drop-in method described in any one of the preceding items [1] to [4].

[0029] Invention Effects

[0030] The present invention provides a liquid crystal sealant for liquid crystal dispensing that is both transparent and highly adhesive, and a liquid crystal display unit encapsulated using its cured product. Attached Figure Description

[0031] Figure 1 This is a diagram of the bonding substrate used in the adhesive bonding test. Detailed Implementation

[0032] The liquid crystal sealant for liquid crystal droplet method of the present invention contains a curable compound, a filler and a thermosetting agent, wherein the primary particle size of the filler is 0.3 μm or less, the filler content is 5 parts by mass or less relative to 100 parts by mass of the curable compound, and the haze value of the cured liquid crystal sealant for liquid crystal droplet method is 60% or less when the film thickness is 100 μm.

[0033] The particle size of the filler can be measured using a laser diffraction / scattering particle size analyzer (dry type) (manufactured by Shinsei Corporation; LMS-30). Alternatively, for commercially available products, the method is not limited to the above; values ​​explicitly stated in each company's product catalog can be used.

[0034] Liquid crystal sealants appear white because the fillers they contain scatter light. Therefore, to improve the transparency of liquid crystal sealants, it is preferable to reduce the filler content while decreasing the filler particle size. Specifically, the primary particle size of the filler is preferably 0.3 μm or less, more preferably 0.2 μm or less, and particularly preferably 0.1 μm or less. There is no particular limitation on the preferred lower limit, but when considering the compatibility with the liquid crystal sealant, the primary particle size of the filler is preferably 0.01 μm or more. Furthermore, the filler content is preferably 5 parts by mass or less, more preferably 2.5 parts by mass or less, relative to 100 parts by mass of the curable compound. There is no particular limitation on the preferred lower limit, but when considering adhesiveness, the filler content is preferably 1 part by mass or more. One type of filler may be used, or a mixture of multiple fillers may be used.

[0035] The liquid crystal sealant of the present invention is preferably transparent. In the present invention, the transparency and haze are evaluated as follows.

[0036] Transparency evaluation is performed by fabricating a liquid crystal cell and observing the corners of the liquid crystal cell using a transmission mode optical microscope. Ideally, the liquid crystal sealant should be transparent to the point where the boundary with the liquid crystal is slightly visible; more preferably, the boundary should be invisible and the cell essentially integrated.

[0037] Haze evaluation was conducted as follows: using a haze meter (Tokyo Denshoku Manufacturing Co., Ltd.: TC-H3DPK), with the empty state as the zero point, the haze was measured by irradiation at 3000 mJ / cm². 2 The thickness of the cured material, which is 100 μm, is measured by curing under ultraviolet light (measurement wavelength: 365 nm) at 120°C for 60 minutes. The haze value is preferably 60% or less, more preferably 50% or less, and particularly preferably 40% or less.

[0038] The liquid crystal sealant of the present invention preferably has high adhesiveness. In the present invention, the adhesiveness is evaluated as follows.

[0039] A liquid crystal sealant containing 1% by weight of 4μm glass fiber was applied to a photoalignment film substrate in the form of a corner with a radius of 0.5mm and a length of 1cm × 1cm. The opposing photoalignment film substrates were then bonded together and irradiated with a UV irradiation machine at 3000mJ / cm². 2 (Measurement wavelength: 365nm) ultraviolet light was applied, followed by heating at 120°C for 60 minutes to bond the substrate. The resulting bonded substrate was then cut into the shape shown. Figure 1 The shape shown is only an illustration of the exposed lower substrate of the display's terminal portion. A universal testing machine (Shimadzu Corporation: Autograph AG-Xplus500N) with 3mmφ pin-shaped terminals is used to press the lower substrate at a position 4mm diagonally opposite the corner of the applied liquid crystal sealant. The maximum load during substrate peeling is measured, and the adhesive strength is determined accordingly. The adhesive strength is preferably 1.0 kgf or more, more preferably 1.5 kgf or more, particularly preferably 2.0 kgf or more, and most preferably 2.5 kgf or more.

[0040] The liquid crystal sealant of the present invention preferably has high flexibility. This is because a liquid crystal sealant with high flexibility can also be used in curved displays and flexible displays, and can follow the stress applied to the display. Flexibility can be evaluated by elastic modulus.

[0041] The results were measured using a universal testing machine (Shimadzu Corporation: Autograph AG-Xplus500N) after irradiation with 3000 mJ / cm². 2 The elastic modulus at room temperature (25°C) of a cured material with a thickness of 100 μm obtained by curing under ultraviolet light (measurement wavelength: 365 nm) at 120°C for 60 minutes is preferably 100 MPa or more and 3000 MPa or less, more preferably 300 MPa or more and 2000 MPa or less, and particularly preferably 400 MPa or more and 1000 MPa or less.

[0042] [Curing compounds]

[0043] The liquid crystal sealant of the present invention contains a curable compound. There are no particular limitations on the curable compound as long as it is a compound that cures using light, heat, or the like, but compounds having (meth)acryloyl or epoxy groups are preferred, and epoxy (meth)acrylates, urethane (meth)acrylates, and polybutadiene compounds are particularly preferred.

[0044] [(Meth)acrylate]

[0045] Specific examples of (meth)acrylates include: N-acryloyloxyethyl hexahydrophthalimide, acryloylmorpholine, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, cyclohexane-1,4-diethanol 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, dihydrodicyclopentadienyl (meth)acrylate, dihydrodicyclopentadienyl oxyethyl (meth)acrylate, 1,4-butanediol di(meth)acrylate, and 1,6-hexanediol. Di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, tricyclodecanediethanol(meth)acrylate, bisphenol A polyethoxydi(meth)acrylate, bisphenol A polypropoxydi(meth)acrylate, bisphenol F polyethoxydi(meth)acrylate, ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, tri(acryloyloxyethyl) isocyanurate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa( Monomers such as methacrylates, pentaerythritol pentamethacrylate, tripentaerythritol hexamethacrylate, tripentaerythritol pentamethacrylate, trimethylolpropane trimethacrylate, trimethylolpropane polyethoxytrimethacrylate, dimethylolpropane tetramethacrylate, diacrylates of neopentyl glycol and hydroxypentaenoic acid esters, or diacrylates of ε-caprolactone adducts of neopentyl glycol and hydroxypentaenoic acid esters. Preferred examples include: o-phenylphenol monoethoxy(meth)acrylate and o-phenylphenol polyethoxy(meth)acrylate.

[0046] [Epoxy (meth)acrylate]

[0047] Epoxy (meth)acrylates can be obtained by reacting epoxy resin with (meth)acrylic acid using known methods. There are no particular restrictions on the epoxy resin used as a raw material, but epoxy resins with more than two functionalities are preferred. Examples include: dimer acid modified epoxy resin, resorcinol diglycidyl ether, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenolic varnish type epoxy resin, cresol phenolic varnish type epoxy resin, bisphenol A phenolic varnish type epoxy resin, bisphenol F phenolic varnish 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, phenolic varnish type epoxy resin with a trihydroxyphenylmethane skeleton, as well as diglycidyl ethers of difunctional phenols such as catechol and resorcinol, diglycidyl ethers of difunctional alcohols, and their halides and hydrogenation products. From the viewpoint of liquid crystal contamination, bisphenol A type epoxy resin and resorcinol diglycidyl ether are preferred. Furthermore, there are no restrictions on the ratio of epoxy groups to (meth)acryloyl groups; the appropriate ratio can be selected from the viewpoint of process suitability.

[0048] It should be noted that partially epoxy (meth)acrylates in which a portion of the epoxy groups are acrylated are suitable. In this case, the acrylate ratio is preferably about 30% to about 70%.

[0049] [Carbamate (meth)acrylate]

[0050] Uraffinate (meth)acrylates have the soft backbone characteristic of urethane structures, resulting in cured products that are soft and have low moisture permeability. They can also follow the bending of flexible displays, making them preferred as curing compounds. Uraffinate (meth)acrylates with polyester structures are even more preferred.

[0051] Carbamate (meth)acrylates can be synthesized by reacting (a) a polyol, (b) an organic polyisocyanate and (c) a hydroxyl-containing (meth)acrylate by conventional methods, using catalysts such as tin compounds as needed.

[0052] In the synthesis of urethane (meth)acrylates, it is preferable to react 1.1 to 2.0 equivalents of isocyanate groups in component (b) with respect to 1 equivalent of the hydroxyl group in component (a) above, and particularly preferably 1.3 to 2.0 equivalents of isocyanate groups in component (b). The reaction temperature is preferably room temperature (25°C) to 100°C.

[0053] Relative to 1 equivalent of the isocyanate group in the reaction product of components (a) and (b), it is preferable to react 0.95 to 1.1 equivalents of the hydroxyl group in component (c). The reaction temperature is preferably room temperature (25°C) to 100°C.

[0054] Specific examples of (a) polyols include: tricyclodecanediethanol, hydrogenated polybutadiene polyol, dimerized 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-eicosenediol, 1-methyl-1,8-octanediol, 2-methyl Diols such as 1,8-octanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, cyclohexane-1,4-diethanol, polyethylene glycol, polypropylene glycol, bisphenol A poly(n≈2~20)ethoxydiol, bisphenol A poly(n≈2~20)propoxydiol (a-1), and polyester polyols (a-2) that are reaction products of these diols (a-1) with diacids or their anhydrides (e.g., succinic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, isophthalic acid, terephthalic acid, phthalic acid, or their anhydrides). Polyester polyols and polyols having aromatic rings are preferred, with polyester polyols having aromatic rings being particularly preferred. Examples of aromatic rings include: aromatic hydrocarbon rings such as benzene ring, naphthalene ring, anthracene ring, and phenanthrene ring; aromatic heterocycles such as furan ring, pyrrole ring, thiophene ring, pyridine ring, thiazole ring, and benzothiazole ring, preferably benzene ring or naphthalene ring.

[0055] Component (a) can be used alone or in combination with two or more.

[0056] Specific examples of (b) organic polyisocyanates include: toluene diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, phenylenediamine diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, phenylenediamine diisocyanate, 1,3-bis(isocyanate-methyl)cyclohexane, trimethylhexamethylene diisocyanate, dimer acid diisocyanate, 1,5-naphthalene diisocyanate, 3,3'-dimethyl-4,4'-diphenylene diisocyanate, etc. Preferably, toluene diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate are also included.

[0057] Specific examples of (c) hydroxyl-containing (meth)acrylates include: 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, and 2-hydroxy-3-phenoxypropyl (meth)acrylate. Preferably, examples include: 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and polyethylene glycol mono(meth)acrylate.

[0058] The lower limit of the weight-average molecular weight of urethane (meth)acrylate in GPC, converted from polystyrene, is preferably 1000 or more, more preferably 2000 or more, particularly preferably 3000 or more, and most preferably 4000 or more. Furthermore, the upper limit is preferably 10000 or less, more preferably 8000 or less, particularly preferably 7000 or less, and most preferably 6000 or less. By ensuring that the weight-average molecular weight of urethane (meth)acrylate is within the above range, good flexibility and moisture permeability are maintained while the viscosity of the liquid crystal sealant remains within an appropriate range.

[0059] [Epoxy Resin]

[0060] As a method of the present invention, it is also preferred that the curable compound contains an epoxy resin.

[0061] There are no particular restrictions on epoxy resins, but epoxy resins with more than two functionalities are preferred. Examples include: dimer acid modified epoxy resins, resorcinol diglycidyl ether, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenolic varnish type epoxy resin, cresol phenolic varnish type epoxy resin, bisphenol A phenolic varnish type epoxy resin, bisphenol F phenolic varnish type epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, hydantoin type epoxy resin, isocyanurate type epoxy resin, phenolic varnish type epoxy resin with a trihydroxyphenylmethane skeleton, as well as diglycidyl ethers of difunctional phenols such as catechol and resorcinol, diglycidyl ethers of difunctional alcohols and their halides and hydrogenation products, etc. From the perspective of liquid crystal pollution, bisphenol A type epoxy resin and resorcinol diglycidyl ether are preferred.

[0062] [Polybutadiene compounds]

[0063] Furthermore, using polybutadiene compounds having epoxy or (meth)acryloyl groups in the curable compound is also a preferred embodiment of the present invention. Examples of epoxy-containing polybutadiene compounds include JP-100 and JP-200 manufactured by Nippon Soda Corporation. Examples of (meth)acryloyl-containing polybutadiene compounds include TEAI-1000 and TE-2000 manufactured by Nippon Soda Corporation.

[0064] 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. Furthermore, from the viewpoint of processability, the upper limit of the number average molecular weight of these polybutadiene compounds is preferably 10000, more preferably 8000, and particularly preferably 6000.

[0065] The curing compound can be used alone or in combination with two or more of the above materials. In the liquid crystal sealant of the present invention, when using a curing compound, the content of the curing compound in the total amount of the liquid crystal sealant is preferably 10% to 95% by mass, more preferably 20% to 90% by mass.

[0066] [filler]

[0067] The liquid crystal sealant of the present invention contains filler. From the viewpoint of transparency, the primary particle size of the filler is preferably 0.3 μm or less, more preferably 0.2 μm or less, and particularly preferably 0.1 μm or less. There is no particular limitation on the preferred lower limit, but when considering the compatibility with the liquid crystal sealant, the primary particle size of the filler is preferably 0.01 μm or more. The filler content is preferably 5 parts by mass or less, more preferably 2.5 parts by mass or less, relative to 100 parts by mass of the curable compound. There is no particular limitation on the preferred lower limit, but when considering adhesiveness, the filler content is preferably 1 part by mass or more. One type of filler may be used, or a mixture of multiple fillers may be used.

[0068] The filler contained in the liquid crystal sealant of the present invention may be any one of organic filler and inorganic filler, or both.

[0069] Examples of organic fillers include: urethane polymer microparticles, acrylic polymer microparticles, styrene polymer microparticles, styrene-olefin copolymer microparticles, and organosilicon microparticles. It should be noted that, as organosilicon microparticles, KMP-594, KMP-597, KMP-598 (manufactured by Shin-Etsu Chemical Industry), and Torayfil are preferred. RTME-5500, 9701, and EP-2001 (manufactured by Toray Dow Corning) are preferred as urethane polymer microparticles, while JB-800T and HB-800BK (manufactured by Negami Kogyo Co., Ltd.) are preferred as styrene polymer microparticles. Rabalon is preferred. RTM T320C, T331C, SJ4400, SJ5400, SJ6400, SJ4300C, SJ5300C, and SJ6300C (manufactured by Mitsubishi Chemical) are preferred as styrene-olefin copolymer microparticles, with Septon being the most suitable. RTM SEPS2004, SEPS2063.

[0070] These organic fillers can be used alone or in combination of two or more. Furthermore, two or more can be used to form a core-shell structure. Preferably, they are urethane polymer microparticles, acrylic polymer microparticles, styrene polymer microparticles, or styrene-olefin copolymer microparticles, with acrylic polymer microparticles being particularly preferred.

[0071] When using the aforementioned acrylic polymer microparticles, a core-shell structured acrylic rubber comprising two types of acrylic rubbers is preferred, and a core-shell structured acrylic rubber with a core layer of n-butyl acrylate and a shell layer of methyl methacrylate is particularly preferred. This is used as a Zefiac... RTM The F-351S is sold by Aker Industries, Ltd.

[0072] In addition, examples of the aforementioned organosilicon microparticles include: organopolysiloxane crosslinked polymer powder, linear dimethyl polysiloxane crosslinked polymer powder, etc. Furthermore, examples of composite silicone rubber include composite silicone rubber obtained by coating the surface of the aforementioned silicone rubber with silicone resin (e.g., polyorganosilsesquioxane resin). Among these microparticles, silicone rubber as linear dimethyl polysiloxane crosslinked polymer powder, or composite silicone rubber microparticles as linear dimethyl polysiloxane crosslinked polymer powder coated with silicone resin, are particularly preferred. These organic fillers can be used alone or in combination of two or more.

[0073] Examples of inorganic fillers include: silicon dioxide, silicon carbide, silicon nitride, boron nitride, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, magnesium oxide, zirconium oxide, aluminum hydroxide, magnesium hydroxide, calcium silicate, aluminum silicate, lithium aluminum silicate, zirconium silicate, barium titanate, glass fiber, carbon fiber, molybdenum disulfide, asbestos, etc. Preferred fillers include: 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. Silica, alumina, and talc are particularly preferred. Two or more of these inorganic fillers can be used in combination.

[0074] [Thermosetting agent]

[0075] The liquid crystal sealant of the present invention contains a thermosetting agent.

[0076] Examples of thermosetting agents include compounds with carboxyl groups bonded to aromatic rings within the molecule, polyamines, polyphenols, and organic acid hydrazides. However, they are not limited to these substances. Examples of aromatic hydrazides include terephthalic acid dihydrazide, isophthalic acid dihydrazide, 2,6-naphthalenedicarboxylic acid dihydrazide, 2,6-pyridinedicarboxylic acid dihydrazide, 1,2,4-phenyltricarboxylic acid trihydrazide, 1,4,5,8-naphthalenetetracarboxylic acid tetrahydrazide, and pyromellitic tetrahydrazide. Additionally, aliphatic acylhydrazides include, for example: formylhydrazide, acetylhydrazide, propionylhydrazide, oxalate dihydrazide, malonate dihydrazide, succinate dihydrazide, glutarate dihydrazide, adipic acid dihydrazide, pimecrolic acid dihydrazide, sebacic acid dihydrazide, 1,4-cyclohexane dihydrazide, tartrate dihydrazide, malate dihydrazide, iminodiacetic acid dihydrazide, N,N'-hexamethylene diaminourea, citrate trihydrazide, hypoazonotriacetic acid trihydrazide, and cyclohexanetricarboxylic acid trihydrazide. Diacylhydrazine, tris(1-hydrazylcarbonylmethyl)isocyanurate, tris(2-hydrazylcarbonylethyl)isocyanurate, tris(1-hydrazylcarbonylethyl)isocyanurate, tris(3-hydrazylcarbonylpropyl)isocyanurate, and bis(2-hydrazylcarbonylethyl)isocyanurate are diacylhydrazines with a hydantoin skeleton, preferably a valine hydantoin skeleton (the skeleton after the carbon atoms of the hydantoin ring are replaced by isopropyl groups). Considering the balance between curing reactivity and latency, the preferred materials are isophthalic acid dihydrazide, malonic acid dihydrazide, adipic acid dihydrazide, tris(1-hydrazylcarbonylmethyl)isocyanurate, tris(1-hydrazylcarbonylethyl)isocyanurate, tris(2-hydrazylcarbonylethyl)isocyanurate, and tris(3-hydrazylcarbonylpropyl)isocyanurate, with tris(2-hydrazylcarbonylethyl)isocyanurate being particularly preferred.

[0077] [Curing Accelerator]

[0078] The liquid crystal sealant of the present invention can have its reactivity further improved by adding a curing accelerator. Examples of curing accelerators include organic acids and imidazoles.

[0079] Organic acids include organic carboxylic acids and organic phosphoric acids, but organic carboxylic acids are preferred. Specifically, examples include: aromatic carboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, benzophenone tetracarboxylic acid, and furanyl dicarboxylic acid; succinic acid; adipic acid; dodecanoic acid; sebacic acid; thiodipropionic acid; cyclohexanedicarboxylic acid; tris(carboxymethyl)isocyanurate; tris(2-carboxyethyl)isocyanurate; tris(2-carboxypropyl)isocyanurate; and bis(2-carboxyethyl)isocyanurate.

[0080] In addition, examples of imidazole compounds include: 2-methylimidazolium, 2-phenylimidazolium, 2-undecylimidazolium, 2-heptadecylimidazolium, 2-phenyl-4-methylimidazolium, 1-benzyl-2-phenylimidazolium, 1-benzyl-2-methylimidazolium, 1-cyanoethyl-2-methylimidazolium, 1-cyanoethyl-2-phenylimidazolium, 1-cyanoethyl-2-undecylimidazolium, 2,4-diamino-6-(2'-methylimidazolium(1'))ethyl-triazine, 2,4-diamino-6-(2'-undecyl ... Ethyl-triazine, 2,4-diamino-6-(2'-ethyl-4-methylimidazole (1'))ethyl-triazine, 2,4-diamino-6-(2'-methylimidazole (1'))ethyl-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-di(cyanoethoxymethyl)imidazole, etc.

[0081] In the liquid crystal sealant of the present invention, when a curing accelerator is used, the content of the curing accelerator in the total amount of the liquid crystal sealant is preferably 0.1% to 10% by mass, more preferably 1% to 5% by mass.

[0082] [Photoradical polymerization initiator]

[0083] The liquid crystal sealant of the present invention may contain a photoradical polymerization initiator. As a photoradical polymerization initiator, there are no particular limitations on compounds that generate free radicals or acids and initiate chain polymerization reactions through irradiation with ultraviolet or visible light. Examples include: benzoyl dimethyl ketal, 1-hydroxycyclohexylphenyl ketone, diethylthioxanthone, benzophenone, 2-ethylanthraquinone, 2-hydroxy-2-methylphenylacetone, 2-methyl-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, camphorquinone, 9-fluorenone, diphenyl disulfide, etc. Specifically, examples 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.), etc. Among them, IRGACURE, as an oxime ester initiator, is preferred. RTMOXE01, OXE02, OXE03, OXE04.

[0084] Furthermore, from the viewpoint of liquid crystal contamination, it is preferable to use a photoradical polymerization initiator having an intramolecular (meth)acryloyl group, for example, the reaction product of 2-methacryloyloxyethyl isocyanate and 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one is preferred. This compound can be obtained by the method described in International Publication No. 2006 / 027982.

[0085] In the liquid crystal sealant of the present invention, when a photoradical polymerization initiator is used, the content of the photoradical polymerization initiator in the total amount of the liquid crystal sealant is preferably 0.001% to 3% by mass, more preferably 0.002% to 2% by mass.

[0086] [Thermal free radical polymerization initiator]

[0087] The liquid crystal sealant of the present invention can improve the curing speed and curability by containing a thermal free radical polymerization initiator.

[0088] There are no particular limitations on thermal free radical polymerization initiators, as long as they are compounds that generate free radicals through heating and initiate a chain polymerization reaction. Examples include organic peroxides, azo compounds, benzoin compounds, benzoin ether compounds, acetophenone compounds, and benzidine alcohol, with benzidine alcohol being preferred. For example, Kayamek can be obtained as a commercially available organic peroxide. RTM A, M, R, L, LH, SP-30C; Parkadox CH-50L, BC-FF; Cadox B-40ES; Parkadox14; 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; Parkadox16; Kayacarbon RTM BIC-75, AIC-75 (manufactured by AKZO Chemical 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 RTMH, D; Peroyl RTM IB, IPP; Perocta RTM ND (manufactured by Nippon Oil Co., Ltd.), etc.

[0089] In addition, as azo compounds, VA-044, 086, V-070, VPE-0201, VSP-1001 (manufactured by Wako Pure Chemical Industries, Ltd.) are available in commercially available forms.

[0090] As a thermal free radical polymerization initiator, it is preferable to have a thermal free radical polymerization initiator that does not have oxygen-oxygen bonds (-OO-) or nitrogen-nitrogen bonds (-N=N-) within the molecule. Thermal free radical polymerization initiators that have oxygen-oxygen bonds (-OO-) or nitrogen-nitrogen bonds (-N=N-) within the molecule generate a large amount of oxygen or nitrogen gas when generating free radicals, thus curing with residual bubbles in the liquid crystal sealant, which may lead to a decrease in adhesive strength, a decrease in moisture permeability, and a decrease in properties under humid and hot environments. Thermal free radical polymerization initiators based on benzenepinal (including substances obtained by chemically modifying benzenepinal) are particularly preferred. Specifically, examples include: benzinolide, 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-tetra(4-methylphenyl)ethane, and 1,2-diphenoxy-1,1,2,2-tetra(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 Alkoxy-1,1,2,2-tetraphenylethane, 1-hydroxy-2-tert-butyldimethylsilyloxy-1,1,2,2-tetraphenylethane, etc., preferably 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, more preferably 1-hydroxy-2-trimethylsilyloxy-1,1,2,2-tetraphenylethane, 1,2-bis(trimethylsilyloxy)-1,1,2,2-tetraphenylethane, particularly preferably 1,2-bis(trimethylsilyloxy)-1,1,2,2-tetraphenylethane.

[0091] The aforementioned benpinacol is sold by companies such as Tokyo Chemical Industry Co., Ltd. and Wako Pure Chemical Industries Co., Ltd. Furthermore, the etherification of the hydroxyl group of benpinacol can be readily synthesized using known methods. Additionally, the silyl etherification of the hydroxyl group of benpinacol can be achieved by heating the corresponding benpinacol with various silylating agents in the presence of a basic catalyst such as pyridine. Examples of commonly known silylating agents include trimethylchlorosilane (TMCS), hexamethyldisilazane (HMDS), N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), triethylchlorosilane (TECS), and tert-butylmethylsilane (TBMS), all of which are known as trimethylsilylating agents. These reagents are readily available from the market, including from silicon derivative manufacturers. The reaction amount of the silylating agent is preferably 1.0 to 5.0 moles relative to 1 mole of the hydroxyl group in the target compound. A further preferred molar ratio is 1.5 to 3.0 molars. When the ratio is less than 1.0 molar, the reaction efficiency is poor, the reaction time is longer, and thus thermal decomposition is promoted. When the ratio is greater than 5.0 molar, separation becomes poor or purification is difficult during recovery.

[0092] In the total amount of the liquid crystal sealant of the present invention, the content of the thermal free radical polymerization initiator is preferably 0.0001% to 10% by mass, more preferably 0.0005% to 5% by mass, and particularly preferably 0.001% to 3% by mass.

[0093] In the liquid crystal sealant of the present invention, additives such as silane coupling agents, free radical polymerization inhibitors, pigments, leveling agents, defoamers, and solvents may also be added as needed.

[0094] [Silane coupling agent]

[0095] Examples of silane coupling agents include: 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, N-(2-(vinylbenzylamino)ethyl)-3-aminopropyltrimethoxysilane hydrochloride, 3-methacryloyloxypropyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, etc. These silane coupling agents, such as the KBM series and KBE series, are sold by companies like Shin-Etsu Chemical Industry Co., Ltd., and are therefore readily available on the market. When using a silane coupling agent in the liquid crystal sealant of the present invention, the content of the silane coupling agent in the total amount of the liquid crystal sealant is preferably 0.05% to 3% by mass.

[0096] [Free radical polymerization inhibitors]

[0097] As the aforementioned free radical polymerization inhibitors, there are no particular restrictions on the use of compounds that inhibit polymerization by reacting with free radicals generated by photoradical polymerization initiators, thermal free radical polymerization initiators, etc. Quinones, piperidines, hindered phenols, nitroso compounds, etc. can be used. Specifically, the following can be listed: naphthoquinone, 2-hydroxynaphthoquinone, 2-methylnaphthoquinone, 2-methoxynaphthoquinone, 2,2,6,6-tetramethylpiperidine-1-oxy, 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxy, 2,2,6,6-tetramethyl-4-methoxypiperidine-1-oxy, 2,2,6,6-tetramethyl-4-phenoxypiperidine-1-oxy, hydroquinone, 2-methylhydroquinone, 2-methoxyhydroquinone, p-benzoquinone, butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butylcresol, stearate β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 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'-hydroxyphenylpropionate)methane], 1,3,5-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)-triazine-2,4,6-(1H,3H,5H)trione, p-methoxyphenol, 4-methoxy-1-naphthol, thiodiphenylamine, aluminum salts of N-nitrosophenylhydroxylamine, trade name ADK STAB LA-81, trade name ADK STAB LA-82 (manufactured by Adico Corporation), etc., but not limited to these substances. Among them, free radical polymerization inhibitors of naphthoquinones, hydroquinones, nitroso compounds, and piperazines are preferred, and naphthoquinone, 2-hydroxynaphthoquinone, hydroquinone, 2,6-di-tert-butyl-p-cresol, and POLYSTOP 7300P (manufactured by Hapton Corporation) are even more preferred, with POLYSTOP 7300P (manufactured by Hapton Corporation) being the most preferred.

[0098] In the total amount of the liquid crystal sealant of the present invention, the content of the free radical polymerization inhibitor is preferably 0.0001% to 1% by mass, more preferably 0.001% to 0.5% by mass, and particularly preferably 0.01% to 0.2% by mass.

[0099] As an example of a method for obtaining the liquid crystal sealant of the present invention, the following method can be described. First, a curable compound, a photoradical polymerization initiator, a thermal radical polymerization initiator, and a radical polymerization inhibitor are dissolved by heating. Next, the mixture is cooled to room temperature, and then a thermosetting agent, a curing accelerator, a filler, a silane coupling agent, a defoamer, a leveling agent, and a solvent, etc., are added. The mixture is then uniformly mixed using a known mixing device such as a three-roll mill, a sand mill, or a ball mill, and filtered using a metal mesh, thereby manufacturing the liquid crystal sealant of the present invention.

[0100] Examples of liquid crystal display units of the present invention are shown below.

[0101] The liquid crystal display unit of the present invention is obtained by arranging a pair of substrates on which predetermined electrodes are formed at a predetermined interval, sealing the surrounding area with the liquid crystal sealant of the present invention, and sealing liquid crystal in the gap. There are no particular limitations on the type of liquid crystal to be sealed. Here, the substrate is composed of a composite substrate comprising glass, quartz, plastic, silicon, etc., at least one of which has light transmittance. As a manufacturing method, spacers such as glass fibers (gap control materials) are 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 screen printing apparatus, and then pre-cured at 80°C to 120°C as needed. Then, liquid crystal is dropped onto the inside of the dam 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. Furthermore, when used in a photothermal hybrid form, the liquid crystal sealant is photocured by irradiating it with ultraviolet light using an ultraviolet irradiation machine. The ultraviolet irradiation dose is preferably 500 mJ / cm². 2 ~6000mJ / cm 2 More preferably 1000 mJ / cm 2 ~4000mJ / cm 2 Irradiation dose (measurement wavelength: 365nm). Then, as needed, 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. The liquid crystal display unit of the present invention obtained in this manner does not have display defects caused by liquid crystal contamination, and has excellent adhesion, moisture resistance, and reliability. As spacers, examples include glass fibers, silica microspheres, polymer microspheres, etc. Their diameter varies depending on the purpose, preferably 2μm to 8μm, more preferably 4μm to 7μm. The amount of spacer used relative to 100 parts by weight of the liquid crystal sealant of the present invention is preferably 0.1 parts by weight to 4 parts by weight, more preferably about 0.5 parts by weight to about 2 parts by weight, and particularly preferably about 0.9 parts by weight to about 1.5 parts by weight.

[0102] [Example]

[0103] The present invention will now be described in more detail through embodiments, but the invention is not limited to these embodiments. It should be noted that, unless otherwise stated, "parts" and "%" are mass measurements in this document.

[0104] [Synthesis example 1]

[0105] In a flask equipped with a thermometer, condenser, and stirrer, 776.99 g of methylpentanediol was added to a polyester polyol (manufactured by Kuraray Co., Ltd., P-2012, hydroxyl value 54.6 mgKOH / g) containing adipic acid and isophthalic acid, and 131.68 g of toluene diisocyanate (manufactured by Tosoh Co., Ltd., Coronate T-100, molecular weight 174.2), and the reaction was carried out at 80 °C. The isocyanate content was determined by adding excess amine and performing a reverse titration with hydrochloric acid, confirming that the value was within ±2% of the calculated residual isocyanate content. Next, 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 the mixture was stirred at 80 °C to allow the reaction to proceed until the absorption spectrum of the isocyanate group in the infrared absorption spectrum (2280 cm⁻¹) was obtained. -1 The ) disappeared, thus yielding a urethane acrylate oligomer with a weight-average molecular weight of 6300.

[0106] [Synthesis example 2]

[0107] 100 parts (0.28 mol) of commercially available benzidine alcohol (manufactured by Tokyo Chemical Industry) were 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 (manufactured by Shin-Etsu Chemical Industry) as a silylating agent were added. The mixture was heated to 70°C and stirred for 2 hours. The resulting reaction solution was cooled, and 200 parts of water were added while stirring to precipitate the product and deactivate any unreacted silylating agent. The precipitated product was filtered and thoroughly washed with water. The resulting product was then dissolved in acetone, recrystallized with water, and purified. 105.6 parts (88.3% yield) of 1,2-bis(trimethylsiloxy)-1,1,2,2-tetraphenylethane, the target product, were obtained.

[0108] [Examples 1-17, Comparative Examples 1-9]

[0109] The curable compound, photoradical polymerization initiator, and radical polymerization inhibitor were dissolved at 90°C in the proportions shown in Tables 1-3 below. After cooling to room temperature, a thermal radical polymerization initiator, thermosetting agent, curing accelerator, organic filler, inorganic filler, and silane coupling agent were added and stirred. The mixture was then dispersed using a three-roll mill and filtered through a 635-mesh metal mesh to prepare the liquid crystal sealant. The particle size of the filler was specified in the respective company's product catalog.

[0110] [evaluate]

[0111] [Haze]

[0112] A 100 μm thick film was formed by sandwiching the liquid crystal sealant manufactured in the examples and comparative examples between polyethylene terephthalate (PET) films, and the film was irradiated with a UV irradiation machine at 3000 mJ / cm². 2 The film was subjected to ultraviolet light (measurement wavelength: 365nm) and then placed in an oven for heat curing at 120°C for 60 minutes. The resulting cured film was cut into 3cm × 3cm squares, and the polyethylene terephthalate film was then peeled off. The haze value was measured using a haze meter (Tokyo Denshoku Manufacturing: TC-H3DPK), with the empty state as the zero point. The results are recorded in Tables 1 to 3.

[0113] [Elastic Modulus]

[0114] A 100 μm thick film was formed by sandwiching the liquid crystal sealant manufactured in the examples and comparative examples between polyethylene terephthalate (PET) films, and the film was irradiated with a UV irradiation machine at 3000 mJ / cm². 2 (Measurement wavelength: 365nm) Ultraviolet light was applied, and then the film was placed in an oven and heat-cured at 120°C for 60 minutes. The resulting cured film was cut into dumbbell-shaped test pieces according to JIS 7113-1 (1 / 2) with an overall length of 75mm, an overall width of 10mm, and a thickness of 100μm (the narrow parallel section is 30mm long × 5mm wide). The polyethylene terephthalate film was then peeled off, and tensile tests were performed using a universal testing machine (Shimadzu Autograph AG-Xplus500N) at a temperature of 25°C, a clamping length of 50mm, and a test speed of 5mm / min. The elastic modulus was calculated from the tensile stress and strain results within the proportional limits. The results are recorded in Tables 1 to 3.

[0115] Fabrication of substrates with photo-alignment films

[0116] A photo-alignment film solution (manufactured by Nissan Chemical Industries, Ltd.: NRB-U738) was spin-coated onto a glass substrate, pre-baked on a hot plate at 80°C for 3 minutes, and then baked in an oven at 230°C for 30 minutes. Finally, the substrate was irradiated with 500 mJ / cm² light using a UV irradiator equipped with a polarizing filter. 2 Ultraviolet light (measured at wavelength: 254nm) was used for alignment treatment, and the substrate was further baked in an oven at 230°C for 30 minutes to obtain a photoaligned film substrate.

[0117] [Transparency Assessment]

[0118] In the examples and comparative examples, 1% by weight of 4 μm glass fiber was added as a spacer to the liquid crystal sealant, and the mixture was stirred using a planetary stirrer (EME Corporation: VMX-360). The prepared liquid crystal sealant was applied in a 1 cm × 1 cm square onto the prepared photoalignment film substrate, and a predetermined amount of liquid crystal (Merck Corporation: MLC-3007) was dropped onto its center. The opposing photoalignment film substrates were then bonded together under vacuum, and subsequently irradiated with a UV irradiator at 3000 mJ / cm². 2 The liquid crystal cell was fabricated by exposing the liquid crystal sealant to ultraviolet light (measurement wavelength: 365 nm) and then heating it at 120°C for 60 minutes. The corners of the resulting liquid crystal cells were observed using a transmission mode optical microscope. A state where the liquid crystal sealant was transparent and the boundary with the liquid crystal was not visible, indicating near-integration, was rated as ○. A state where the boundary was slightly visible was rated as △. A state where the transparency was compromised due to scattering by the filler in the liquid crystal sealant, and the boundary with the liquid crystal was clearly visible, was rated as ×. The results are recorded in Tables 1 to 3.

[0119] [Adhesive strength]

[0120] In the examples and comparative examples, 1% by weight of 4 μm glass fiber was added as a spacer to the liquid crystal sealant, and the mixture was stirred using a planetary stirrer (EME Corporation: VMX-360). The prepared liquid crystal sealant was applied to the prepared photoalignment film substrate in the form of a corner portion with a radius of 0.5 mm and a length of 1 cm × 1 cm. The opposing photoalignment film substrates were then bonded together and irradiated with a UV irradiator at 3000 mJ / cm². 2 (Measurement wavelength: 365nm) ultraviolet light was applied, followed by heating at 120°C for 60 minutes to bond the substrate. The resulting bonded substrate was then cut into the shape shown. Figure 1The shape shown is only an exposed portion of the lower substrate of the display terminal. A universal testing machine (Shimadzu Corporation: Autograph AG-Xplus500N) with 3mm φ pin-shaped terminals was used to press the lower substrate, positioned 4mm diagonally across the corner of the coated liquid crystal sealant, and the maximum load during substrate peeling was measured to determine the adhesive strength. Regarding the results, a sufficiently strong adhesive strength (maximum load ≥ 2.0 kgf) was rated as ○, a slightly weak adhesive strength (maximum load ≥ 1.0 kgf but < 2.0 kgf) as △, and a maximum load < 1.0 kgf and significantly insufficient adhesive strength as ×. The results are recorded in Tables 1 to 3.

[0121] Table 1

[0122]

[0123] Table 2

[0124]

[0125] Table 3

[0126]

[0127] Table 4

[0128]

[0129] The results in Tables 1 to 4 confirm that the liquid crystal sealant of the present invention possesses both transparency and high adhesiveness. Furthermore, the liquid crystal sealant of the present invention also confirms high flexibility.

[0130] Industrial practicality

[0131] The liquid crystal sealant of the present invention is particularly suitable for use as a liquid crystal sealant for transparent liquid crystal displays due to its combination of transparency and high adhesiveness.

Claims

1. A liquid crystal sealant for liquid crystal dispensing, wherein the liquid crystal sealant for liquid crystal dispensing comprises a curable compound, a filler, and a thermosetting agent, wherein, The thermosetting agent is an organic acid hydrazide compound or pentaerythritol tetra(3-mercaptobutyrate). The primary particle size of the filler is below 0.3 μm. The filler content is 1 part by mass and less than 5 parts by mass relative to 100 parts by mass of the curable compound, and The haze value of the cured liquid crystal sealant used in the liquid crystal droplet method is below 60% when the film thickness is 100 μm.

2. The liquid crystal sealant for liquid crystal dispensing as described in claim 1, wherein, The elastic modulus of the cured liquid crystal sealant for the liquid crystal droplet method, as determined by a universal testing machine, at 25°C is less than 2000 MPa.

3. The liquid crystal sealant for liquid crystal dispensing as described in claim 1 or 2, wherein, The liquid crystal droplet method uses a liquid crystal sealant containing urethane (meth)acrylate as the curing compound.

4. The liquid crystal sealant for liquid crystal dispensing as described in claim 3, wherein, The urethane (meth)acrylate is obtained by reacting (a) a polyol having an aromatic ring, (b) an organic polyisocyanate and (c) a hydroxyl-containing (meth)acrylate.

5. The liquid crystal sealant for liquid crystal dispensing as described in any one of claims 1, 2, and 4, wherein, The liquid crystal sealant used in the liquid crystal droplet method is a sealant for transparent liquid crystal displays.

6. The liquid crystal sealant for liquid crystal dispensing as described in claim 3, wherein, The liquid crystal sealant used in the liquid crystal droplet method is a sealant for transparent liquid crystal displays.

7. A liquid crystal display unit, wherein, The liquid crystal display unit is encapsulated with a liquid crystal sealant using the liquid crystal droplet method according to any one of claims 1 to 6.

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