Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/44—Polymerisation in the presence of compounding ingredients, e.g. plasticisers, dyestuffs, fillers
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K3/00—Materials not provided for elsewhere
  • C09K3/10—Materials in mouldable or extrudable form for sealing or packing joints or covers
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1339—Gaskets; Spacers; Sealing of cells

Definitions

• the present invention relates to a sealant for liquid crystal display elements.
• a liquid crystal dropping method using a photothermal curing type sealant as disclosed in Patent Documents 1 and 2 has been used.
• the dropping method first, a frame-shaped seal pattern is formed on one of two transparent substrates with electrodes by dispensing. Next, while the sealant is still in an uncured state, minute droplets of liquid crystal are dropped onto the entire frame of the transparent substrate, and the other transparent substrate is immediately bonded to the seal portion, and light such as ultraviolet light is irradiated to cause temporary curing.
• liquid crystal display elements After that, the liquid crystal is heated during liquid crystal annealing to cause full curing, and a liquid crystal display element is produced. If the substrates are bonded under reduced pressure, liquid crystal display elements can be manufactured with extremely high efficiency, and the dropping method is currently the mainstream method for manufacturing liquid crystal display elements.
• Sealant for liquid crystal display elements is usually blended with inorganic fillers such as talc to improve adhesion and moisture permeability. Sealants containing such inorganic fillers have poor transparency because the inorganic filler scatters light and appears cloudy. On the other hand, if the content of inorganic filler is reduced to improve transparency, there is a risk that the adhesion and moisture permeability of the sealant to the substrate will deteriorate, and it has been difficult to obtain sealants with excellent transparency, adhesion, and moisture permeability with conventional sealants.
• the object of the present invention is to provide a sealant for liquid crystal display elements that has excellent transparency, adhesion, and moisture permeability prevention properties.
• Disclosure 1 relates to a sealant for liquid crystal display elements, which contains a curable resin, an inorganic filler, a photopolymerization initiator, and a heat curing agent, and in which a 100 ⁇ m-thick cured product of the sealant for liquid crystal display elements has a haze of 60% or less, and a 300 ⁇ m-thick cured product has a moisture permeability of 90 g/ m2 ⁇ 24 hr or less in an environment of 80° C. and 90% RH, as measured in accordance with JIS Z 0208.
• the present disclosure 2 relates to the sealant for liquid crystal display elements according to the present disclosure 1, wherein the adhesive strength of the cured product of the sealant for liquid crystal display elements to glass at 25° C.
• the present disclosure 3 is the sealant for liquid crystal display elements according to the present disclosure 1 or 2, wherein the inorganic filler has a refractive index of 1.50 or more and 1.60 or less, and the difference in refractive index between the cured product of the curable resin and the inorganic filler is 0.08 or less.
• the present disclosure 4 is the sealant for a liquid crystal display element according to the present disclosure 1, 2 or 3, wherein the inorganic filler is a silica-titania composite oxide.
• the present disclosure 5 is the sealant for a liquid crystal display element according to the present disclosure 1, 2, 3, or 4, wherein the inorganic filler has an M value of 20 or more.
• the present disclosure 6 is a sealant for liquid crystal display elements according to claim 1, 2, 3, 4 or 5, wherein the heat curing agent contains an imidazole derivative that is liquid at 25°C. The present invention will be described in detail below.
• the inventors discovered that by adjusting the haze of a 100 ⁇ m thick cured product and the moisture permeability of a 300 ⁇ m thick cured product in an environment of 80°C and 90% RH, it is possible to obtain a sealant for liquid crystal display elements that is excellent in transparency, adhesion, and moisture permeability prevention, and thus completed the present invention.
• the sealant for liquid crystal display devices of the present invention has a haze of 60% or less when cured at a thickness of 100 ⁇ m.
• the upper limit of the haze of the cured product is preferably 40%.
• the substantial lower limit is 1%.
• the haze of the cured product can be measured using a spectrometer such as AUTOMATIC HAZE METER MODEL TC-III DPK (manufactured by Tokyo Denshoku Co., Ltd.).
• the cured product used for measuring the haze is a 100 ⁇ m thick cured product obtained by irradiating a sealant with ultraviolet light having a wavelength of 365 nm and an illuminance of 100 mW/ cm2 through a 340 nm cut filter for 30 seconds and then heating at 120° C. for 60 minutes using a UV irradiator.
• a UV irradiator for example, MB1500T-3 (manufactured by Sen Special Light Source Co., Ltd.) can be used.
• the sealant for liquid crystal display elements of the present invention has a moisture permeability of 90 g/ m2 ⁇ 24 hr or less in an environment of 80° C. and 90% RH for a cured product having a thickness of 300 ⁇ m, measured in accordance with JIS Z 0208.
• the moisture permeability is 90 g/ m2 ⁇ 24 hr or less, the resulting liquid crystal display element has excellent reliability.
• the preferred upper limit of the moisture permeability is 85 g/ m2 ⁇ 24 hr. Further, there is no particular preferred lower limit for the moisture permeability, but the substantial lower limit is 10 g/m 2 ⁇ 24 hr.
• the cured product for measuring the moisture permeability is a 300 ⁇ m thick cured product obtained by irradiating a sealant with ultraviolet light having a wavelength of 365 nm and an illuminance of 100 mW/ cm2 through a 340 nm cut filter for 30 seconds using a UV irradiator, followed by heating for 60 minutes at 120° C.
• a UV irradiator for example, MB1500T-3 (manufactured by Sen Special Light Source Co., Ltd.) or the like can be used.
• the sealant for liquid crystal display elements of the present invention preferably has a lower limit of 2.0 kgf/cm in adhesive strength to glass at 25° C. of the cured product.
• the adhesive strength to glass is 2.0 kgf/cm or more, the obtained liquid crystal display element has higher reliability.
• the substantial upper limit is 10.0 kgf/cm.
• the adhesive strength to glass can be measured by the following method. That is, a sealant is dotted on one of two glass substrates so that the diameter of the substrates when bonded together is 3 mm. The glass substrate with the sealant dotted on it and the other glass substrate are bonded together in a cross shape via the sealant.
• UV irradiator ultraviolet light with a wavelength of 365 nm and an illuminance of 100 mW/cm 2 is irradiated through a 340 nm cut filter for 30 seconds, and then heated at 120°C for 60 minutes to harden the sealant, thereby obtaining a test piece.
• the obtained test piece is subjected to a tensile test under the condition of 5 mm/sec with chucks arranged above and below in an environment of 25°C, so that the adhesive strength to the glass can be measured.
• the UV irradiator for example, MB1500T-3 (manufactured by Sen Special Light Source Co., Ltd.) or the like can be used.
• the sealing material for a liquid crystal display element of the present invention contains an inorganic filler.
• the inorganic filler preferably has a refractive index of 1.50 or more and 1.60 or less, and the absolute difference between the refractive index of the cured product of the curable resin described below and the refractive index of the inorganic filler is 0.08 or less.
• the refractive index of the inorganic filler is 1.50 or more and 1.60 or less, and the absolute difference between the refractive index of the cured product of the curable resin described below and the refractive index of the inorganic filler is 0.08 or less, the obtained sealant for liquid crystal display elements has excellent transparency.
• the lower limit of the refractive index of the inorganic filler is more preferably 1.54, and the upper limit thereof is more preferably 1.58.
• the upper limit of the absolute difference between the refractive index of the cured product of the curable resin described later and the refractive index of the inorganic filler is more preferably 0.06, and even more preferably 0.04.
• the refractive index refers to the refractive index at the sodium D line measured using an Abbe refractometer at 25° C.
• the Abbe refractometer examples include the Universal Abbe Refractometer ER-7MW (manufactured by ERMA).
• the cured product of the curable resin for measuring the refractive index can be obtained, for example, by the following method. That is, first, a photopolymerization initiator and a heat curing agent are mixed with a curable resin to obtain a curable resin composition.
• the obtained curable resin composition is irradiated with ultraviolet light having a wavelength of 365 nm and an illuminance of 100 mW/ cm2 through a 340 nm cut filter for 30 seconds using a UV irradiator, and then heated at 120°C for 60 minutes to obtain a cured product to be used for measuring the refractive index.
• the UV irradiator for example, MB1500T-3 (manufactured by Sen Special Light Source Co., Ltd.) can be used.
• the inorganic filler examples include silica-titania composite oxide, talc particles, and the like. Among these, silica-titania composite oxide is preferred. By containing the silica-titania composite oxide, the sealing agent for liquid crystal display elements of the present invention becomes more excellent in transparency, adhesion, and moisture permeability prevention.
• the inorganic filler is preferably surface-treated, and more preferably has hydrophobic groups on its surface. By having hydrophobic groups on the surface of the inorganic filler, the resulting sealant for liquid crystal display elements has better alignment film adhesion.
• examples of the hydrophobic group include an alkyl group having 1 to 20 carbon atoms, an epoxy group, an amino group, an alkoxyl group, a vinyl group, a (meth)acryloyl group, a sulfide group, a mercapto group, an isocyanate group, a ureido group, a pyridyl group, a styryl group, etc.
• an alkyl group having 1 to 20 carbon atoms is preferred, and a methyl group is more preferred.
• the above "(meth)acryloyl” means acryloyl or methacryloyl.
• the inorganic filler having the above-mentioned hydrophobic groups on its surface can be obtained by a method of surface-treating an untreated inorganic filler (base particle) with a surface treatment agent.
• Examples of surface treatment agents used for the surface treatment of the above-mentioned base particles include silazane compounds, siloxane compounds, various silane coupling agents, various titanium coupling agents, various aluminum-based coupling agents, acid anhydrides, higher fatty acids, isocyanate compounds, acid chloride compounds, phosphate ester compounds, aldehyde compounds, and the like.
• silane coupling agents are preferred because they are highly effective in improving the alignment film adhesion of the resulting sealant for liquid crystal display elements.
• silane coupling agents used as the surface treatment agent include methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, methyltrichlorosilane, butyltrichlorosilane, trifluoropropyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,
• Examples of methods for surface treating the base particles include dissolving the surface treatment agent in an organic solvent such as alcohol or toluene, dispersing the base particles in the resulting solution, and allowing them to react.
• the preferred upper limit of the average primary particle size of the inorganic filler is 0.5 ⁇ m. By making the average primary particle size of the inorganic filler 0.5 ⁇ m or less, light scattering is suppressed and the transparency is superior, and the obtained sealant for liquid crystal display elements has superior transparency.
• the more preferred upper limit of the average primary particle size of the inorganic filler is 0.4 ⁇ m.
• the lower limit of the average primary particle size of the inorganic filler is preferably 0.01 ⁇ m, and more preferably 0.05 ⁇ m.
• the average primary particle size refers to the average value of the major axes of 300 particles measured using a SEM-EDX measuring device, such as S-4800 (manufactured by Hitachi High-Technologies Corporation).
• the inorganic filler has a preferred lower limit of M value of 20.
• M value is more preferably 22, and even more preferably 23.
• the upper limit of the M value of the inorganic filler is not particularly limited, and is theoretically 99.9, but a preferred upper limit is 70, a more preferred upper limit is 50, and a further more preferred upper limit is 35.
• the M value of the inorganic filler exceeds 50, the viscosity and thixotropic index of the sealant containing the inorganic filler may increase, making application difficult, and if the M value of the inorganic filler exceeds 70, aggregation of the inorganic filler may occur during surface treatment.
• the M value is a value expressing the hydrophobicity of the particle powder surface, and is the volume percentage of methanol when the particle powder begins to get wet with the mixed liquid when the mixing ratio of the water and methanol mixed liquid is changed (when the methanol ratio is increased).
• the preferred lower limit of the content of the inorganic filler relative to 100 parts by mass of the curable resin described below is 6 parts by mass.
• the content of the inorganic filler is 6 parts by mass or more, the resulting sealant for liquid crystal display elements has better adhesion and moisture permeability prevention properties.
• the more preferred lower limit of the content of the inorganic filler is 9 parts by mass.
• the upper limit of the content of the inorganic filler is preferably 30 parts by mass, more preferably 20 parts by mass, and even more preferably 15 parts by mass.
• the sealant for liquid crystal display elements of the present invention may contain an organic filler within the range that does not impair the object of the present invention.
• the organic filler include polyester fine particles, polyurethane fine particles, vinyl polymer fine particles, and (meth)acrylic polymer fine particles.
• (meth)acrylic means acrylic or methacrylic.
• the sealing agent for a liquid crystal display element of the present invention contains a curable resin.
• the curable resin preferably contains at least one selected from the group consisting of a (meth)acrylic compound and an epoxy compound, and more preferably contains a (meth)acrylic compound and an epoxy compound.
• the (meth)acrylic compound examples include (meth)acrylic acid ester compounds, epoxy (meth)acrylates, and urethane (meth)acrylates. Among these, epoxy (meth)acrylates are preferred. From the viewpoint of reactivity, the (meth)acrylic compound is preferably one having two or more (meth)acryloyl groups in one molecule.
• (meth)acrylate means acrylate or methacrylate
• epoxy (meth)acrylate means a compound in which all epoxy groups in an epoxy compound have been reacted with (meth)acrylic acid.
• Examples of monofunctional (meth)acrylic acid ester compounds include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, Isomyristyl (meth)acrylate, stearyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, cyclohexyl (meth)acrylate, iso
• examples of the bifunctional (meth)acrylic acid ester compounds include 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 2-n-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, Examples of such di(meth)acrylates include butyl di(meth)acrylate,
• examples of the (meth)acrylic acid ester compounds having three or more functional groups include trimethylolpropane tri(meth)acrylate, ethylene oxide-added trimethylolpropane tri(meth)acrylate, propylene oxide-added trimethylolpropane tri(meth)acrylate, caprolactone-modified trimethylolpropane tri(meth)acrylate, ethylene oxide-added isocyanuric acid tri(meth)acrylate, glycerin tri(meth)acrylate, propylene oxide-added glycerin tri(meth)acrylate, pentaerythritol tri(meth)acrylate, tris(meth)acryloyloxyethyl phosphate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythri
• the above-mentioned epoxy (meth)acrylates include, for example, those obtained by reacting an epoxy compound with (meth)acrylic acid in the presence of a basic catalyst according to a conventional method.
• the epoxy compounds used as raw materials for synthesizing the above epoxy (meth)acrylates include, for example, bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol S type epoxy compounds, 2,2'-diallyl bisphenol A type epoxy compounds, hydrogenated bisphenol type epoxy compounds, propylene oxide-added bisphenol A type epoxy compounds, resorcinol type epoxy compounds, biphenyl type epoxy compounds, sulfide type epoxy compounds, diphenyl ether type epoxy compounds, dicyclopentadiene type epoxy compounds, naphthalene type epoxy compounds, phenol novolac type epoxy compounds, orthocresol novolac type epoxy compounds, dicyclopentadiene novolac type epoxy compounds, biphenyl novolac type epoxy compounds, naphthalene phenol novolac type epoxy compounds, glycidyl amine type epoxy compounds, alkyl polyol type epoxy compounds, rubber modified type epoxy compounds, glycidyl ester compounds, etc.
• the above bisphenol A type epoxy compounds commercially available ones include, for example, jER828EL, jER1004 (both manufactured by Mitsubishi Chemical Corporation), EPICLON EXA-850CRP (manufactured by DIC Corporation), and the like.
• the above bisphenol F type epoxy compounds commercially available ones include, for example, jER806 and jER4004 (both manufactured by Mitsubishi Chemical Corporation).
• the above bisphenol S type epoxy compounds commercially available examples include EPICLON EXA1514 (manufactured by DIC Corporation).
• a commercially available example is RE-810NM (manufactured by Nippon Kayaku Co., Ltd.).
• examples of the above hydrogenated bisphenol type epoxy compounds include EPICLON EXA7015 (manufactured by DIC Corporation).
• propylene oxide-added bisphenol A type epoxy compounds commercially available ones include, for example, EP-4000S (manufactured by ADEKA Corporation).
• resorcinol type epoxy compounds a commercially available example is EX-201 (manufactured by Nagase Chemtex Corporation).
• examples of commercially available compounds include jER YX-4000H (manufactured by Mitsubishi Chemical Corporation).
• a commercially available example is YSLV-50TE (manufactured by Nippon Steel Chemical & Material Co., Ltd.).
• a commercially available example is YSLV-80DE (manufactured by Nippon Steel Chemical & Material Co., Ltd.).
• commercially available ones include, for example, EP-4088S (manufactured by ADEKA Corporation).
• naphthalene type epoxy compounds commercially available ones include, for example, EPICLON HP4032 and EPICLON EXA-4700 (both manufactured by DIC Corporation).
• phenol novolac type epoxy compounds commercially available ones include, for example, EPICLON N-770 (manufactured by DIC Corporation).
• ortho-cresol novolac type epoxy compounds commercially available ones include, for example, EPICLON N-670-EXP-S (manufactured by DIC Corporation).
• dicyclopentadiene novolac type epoxy compounds a commercially available example is EPICLON HP7200 (manufactured by DIC Corporation).
• biphenyl novolac type epoxy compounds a commercially available example is NC-3000P (manufactured by Nippon Kayaku Co., Ltd.).
• naphthalenephenol novolac type epoxy compounds a commercially available example is ESN-165S (manufactured by Nippon Steel Chemical & Material Co., Ltd.).
• ESN-165S manufactured by Nippon Steel Chemical & Material Co., Ltd.
• glycidylamine type epoxy compounds commercially available ones include, for example, jER630 (manufactured by Mitsubishi Chemical Corporation), EPICLON 430 (manufactured by DIC Corporation), and TETRAD-X (manufactured by Mitsubishi Gas Chemical Company, Inc.).
• alkyl polyol type epoxy compounds examples include ZX-1542 (manufactured by Nippon Steel Chemical & Material Co., Ltd.), EPICLON 726 (manufactured by DIC Corporation), Epolite 80MFA (manufactured by Kyoeisha Chemical Co., Ltd.), and Denacol EX-611 (manufactured by Nagase ChemteX Corporation).
• EPICLON 726 manufactured by DIC Corporation
• Epolite 80MFA manufactured by Kyoeisha Chemical Co., Ltd.
• Denacol EX-611 manufactured by Nagase ChemteX Corporation
• commercially available ones include, for example, YR-450, YR-207 (both manufactured by Nippon Steel Chemical & Material Co., Ltd.), Epolead PB (manufactured by Daicel Corporation), and the like.
• glycidyl ester compounds include, for example, Denacol EX-147 (manufactured by Nagase Chemtex Corporation).
• Other commercially available epoxy compounds include, for example, YDC-1312, YSLV-80XY, YSLV-90CR (all manufactured by Nippon Steel Chemical & Material Co., Ltd.), XAC4151 (manufactured by Asahi Kasei Corporation), jER1031, jER1032 (all manufactured by Mitsubishi Chemical Corporation), EXA-7120 (manufactured by DIC Corporation), and TEPIC (manufactured by Nissan Chemical Industries, Ltd.).
• epoxy (meth)acrylates commercially available ones include, for example, epoxy (meth)acrylate manufactured by Daicel Allnex Corporation, epoxy (meth)acrylate manufactured by Shin-Nakamura Chemical Co., Ltd., epoxy (meth)acrylate manufactured by Kyoeisha Chemical Co., Ltd., and epoxy (meth)acrylate manufactured by Nagase ChemteX Corporation.
• Examples of the epoxy (meth)acrylates manufactured by Daicel-Allnex include EBECRYL860, EBECRYL3200, EBECRYL3201, EBECRYL3412, EBECRYL3600, EBECRYL3700, EBECRYL3701, EBECRYL3702, EBECRYL3703, EBECRYL3708, EBECRYL3800, EBECRYL6040, and EBECRYL RDX63182.
• Examples of the epoxy (meth)acrylates manufactured by Shin-Nakamura Chemical Co., Ltd. include EA-1010, EA-1020, EA-5323, EA-5520, EA-CHD, and EMA-1020.
• Examples of the epoxy (meth)acrylates manufactured by Kyoeisha Chemical Co., Ltd. include Epoxy Ester M-600A, Epoxy Ester 40EM, Epoxy Ester 70PA, Epoxy Ester 200PA, Epoxy Ester 80MFA, Epoxy Ester 3002M, Epoxy Ester 3002A, Epoxy Ester 1600A, Epoxy Ester 3000M, Epoxy Ester 3000A, Epoxy Ester 200EA, and Epoxy Ester 400EA.
• Examples of the epoxy (meth)acrylates manufactured by Nagase ChemteX Corporation include Denacol Acrylate DA-141, Denacol Acrylate DA-314, and Denacol Acrylate DA-911.
• the above urethane (meth)acrylate can be obtained, for example, by reacting a (meth)acrylic acid derivative having a hydroxyl group with a polyfunctional isocyanate compound in the presence of a catalytic amount of a tin-based compound.
• polyfunctional isocyanate compounds include isophorone diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, diphenylmethane-4,4'-diisocyanate (MDI), hydrogenated MDI, polymeric MDI, 1,5-naphthalene diisocyanate, norbornane diisocyanate, tolidine diisocyanate, xylylene diisocyanate (XDI), hydrogenated XDI, lysine diisocyanate, triphenylmethane triisocyanate, tris(isocyanatephenyl)thiophosphate, tetramethylxylylene diisocyanate, and 1,6,11-undecane triisocyanate.
• MDI diphenylmethane-4,4'-diisocyanate
• XDI xylylene di
• polyfunctional isocyanate compound a chain-extended polyfunctional isocyanate compound obtained by reacting a polyol with an excess of the polyfunctional isocyanate compound can also be used.
• the polyol include ethylene glycol, propylene glycol, glycerin, sorbitol, trimethylolpropane, carbonate diol, polyether diol, polyester diol, and polycaprolactone diol.
• Examples of the (meth)acrylic acid derivative having a hydroxyl group include hydroxyalkyl mono(meth)acrylates, mono(meth)acrylates of dihydric alcohols, mono(meth)acrylates or di(meth)acrylates of trihydric alcohols, and epoxy (meth)acrylates.
• Examples of the hydroxyalkyl mono(meth)acrylate include 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 2-hydroxybutyl(meth)acrylate, and 4-hydroxybutyl(meth)acrylate.
• Examples of the dihydric alcohol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and polyethylene glycol.
• Examples of the trihydric alcohol include trimethylolethane, trimethylolpropane, and glycerin.
• the epoxy (meth)acrylate may, for example, be bisphenol A type epoxy acrylate.
• urethane (meth)acrylates commercially available ones include, for example, urethane (meth)acrylate manufactured by Toagosei Co., Ltd., urethane (meth)acrylate manufactured by Daicel-Allnex Corporation, urethane (meth)acrylate manufactured by Negami Chemical Industries Co., Ltd., urethane (meth)acrylate manufactured by Shin-Nakamura Chemical Co., Ltd., and urethane (meth)acrylate manufactured by Kyoeisha Chemical Co., Ltd.
• Examples of the urethane (meth)acrylates manufactured by Toagosei Co., Ltd. include M-1100, M-1200, M-1210, and M-1600.
• Examples of the urethane (meth)acrylates manufactured by Daicel-Allnex include EBECRYL210, EBECRYL220, EBECRYL230, EBECRYL270, EBECRYL1290, EBECRYL2220, EBECRYL4827, EBECRYL4842, EBECRYL4858, EBECRYL5129, EBECRYL6700, EBECRYL8402, EBECRYL8803, EBECRYL8804, EBECRYL8807, and EBECRYL9260.
• urethane (meth)acrylates manufactured by Kyoeisha Chemical Co., Ltd. include AH-600, AI-600, AT-600, UA-101I, UA-101T, UA-306H, UA-306I, and UA-306T.
• the epoxy compound examples include the epoxy compounds that are raw materials for synthesizing the above-mentioned epoxy (meth)acrylates, partially (meth)acrylic modified epoxy compounds, and the like.
• the partially (meth)acrylic-modified epoxy compound means a compound having one or more epoxy groups and one or more (meth)acryloyl groups in one molecule, which can be obtained, for example, by reacting some of the epoxy groups of an epoxy compound having two or more epoxy groups in one molecule with (meth)acrylic acid.
• the ratio of (meth)acryloyl groups in the total of (meth)acryloyl groups and epoxy groups in the curable resin is 30 mol% or more and 95 mol% or less.
• the curable resin preferably has a hydrogen-bonding unit such as an --OH group, an --NH-- group, or an --NH2 group, from the viewpoint of making the resulting sealant for liquid crystal display elements excellent in low liquid crystal contamination.
• the above curable resins may be used alone or in combination of two or more.
• the sealing agent for liquid crystal display elements of the present invention contains a photopolymerization initiator.
• the photopolymerization initiator include a benzophenone compound, an acetophenone compound, an acylphosphine oxide compound, a titanocene compound, an oxime ester compound, a benzoin ether compound, and a thioxanthone compound.
• photopolymerization initiator examples include 1-hydroxycyclohexyl phenyl ketone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-((4-methylphenyl)methyl)-1-(4-(4-morpholinyl)phenyl)-1-butanone, 2,2-dimethoxy-1,2-diphenylethan-1-one, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2-methyl-1-(4-methylthiophenyl)- ...
• the content of the photopolymerization initiator is preferably 0.01 parts by mass at the lower limit and 10 parts by mass at the upper limit relative to 100 parts by mass of the curable resin. When the content of the photopolymerization initiator is within this range, the resulting sealant for liquid crystal display elements has better storage stability and photocurability.
• a more preferred lower limit of the content of the photopolymerization initiator is 0.1 parts by mass, and a more preferred upper limit is 5 parts by mass.
• the sealing agent for a liquid crystal display element of the present invention may contain a thermal polymerization initiator.
• the thermal polymerization initiator include those composed of an azo compound, an organic peroxide, etc. Among them, a polymeric azo initiator composed of a polymeric azo compound is preferred.
• the thermal polymerization initiators may be used alone or in combination of two or more kinds.
• the "polymeric azo compound” refers to a compound having an azo group, generating radicals capable of curing a (meth)acryloyloxy group by heat, and having a number average molecular weight of 300 or more.
• the preferred lower limit of the number average molecular weight of the polymeric azo compound is 1,000, and the preferred upper limit is 300,000. By having the number average molecular weight of the polymeric azo compound within this range, it can be easily mixed with the curable resin while suppressing liquid crystal contamination.
• a more preferred lower limit of the number average molecular weight of the polymeric azo compound is 5,000, and a more preferred upper limit is 100,000, and an even more preferred lower limit is 10,000, and an even more preferred upper limit is 90,000.
• polymeric azo compound examples include those having a structure in which a plurality of units such as polyalkylene oxide and polydimethylsiloxane are bonded via azo groups.
• polymeric azo compound having a structure in which a plurality of units such as polyalkylene oxide are bonded via the azo group those having a polyethylene oxide structure are preferred.
• Specific examples of the polymeric azo compound include a polycondensate of 4,4'-azobis(4-cyanopentanoic acid) and polyalkylene glycol, and a polycondensate of 4,4'-azobis(4-cyanopentanoic acid) and polydimethylsiloxane having a terminal amino group.
• polymeric azo compounds commercially available ones include, for example, VPE-0201, VPE-0401, VPE-0601, VPS-0501, and VPS-1001 (all manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.).
• non-polymeric azo compounds include V-65 and V-501 (both manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.).
• organic peroxides examples include ketone peroxides, peroxyketals, hydroperoxides, dialkyl peroxides, peroxy esters, diacyl peroxides, and peroxydicarbonates.
• the content of the thermal polymerization initiator is preferably 0.05 parts by mass at the lower limit and 10 parts by mass at the upper limit relative to 100 parts by mass of the curable resin.
• the sealant for liquid crystal display elements of the present invention has superior thermosetting properties.
• the sealant for liquid crystal display elements of the present invention has superior low liquid crystal contamination properties and storage stability.
• a more preferred lower limit of the content of the thermal polymerization initiator is 0.1 parts by mass, and a more preferred upper limit is 5 parts by mass.
• the sealing agent for a liquid crystal display element of the present invention further contains a heat curing agent.
• the heat curing agent include organic acid hydrazides, imidazole derivatives, amine compounds, polyhydric phenol compounds, acid anhydrides, etc. Among them, from the viewpoint of achieving both adhesiveness and moisture permeability, organic acid hydrazides and imidazole derivatives are preferably used. From the viewpoint of achieving both transparency and moisture permeability, the heat curing agent is preferably liquid at 25° C., and an imidazole derivative that is liquid at 25° C. is more preferably used. By using a heat curing agent that is liquid at 25° C., uniform curing is possible and curing unevenness is reduced, which is considered to improve the transparency of the cured product of the obtained sealant for liquid crystal display elements.
• organic acid hydrazide examples include sebacic acid dihydrazide, isophthalic acid dihydrazide, adipic acid dihydrazide, and malonic acid dihydrazide.
• organic acid hydrazides commercially available ones include, for example, organic acid hydrazides manufactured by Otsuka Chemical Co., Ltd., organic acid hydrazides manufactured by Ajinomoto Fine-Techno Co., Ltd., and organic acid hydrazides manufactured by Nippon Finechem Co., Ltd.
• examples of the organic acid hydrazides available from Otsuka Chemical Co., Ltd. examples include SDH and ADH.
• Examples of the organic acid hydrazides manufactured by Ajinomoto Fine-Techno Co., Inc. include Amicure VDH, Amicure VDH-J, Amicure UDH, and Amicure UDH-J.
• the organic acid hydrazide manufactured by Japan Finechem Co., Ltd. is, for example, MDH.
• the content of the heat curing agent is preferably 1 part by mass at the lower limit and 50 parts by mass at the upper limit relative to 100 parts by mass of the curable resin.
• the resulting sealant for liquid crystal display elements has excellent heat curing properties while maintaining storage stability and coatability.
• a more preferred upper limit of the content of the heat curing agent is 30 parts by mass.
• the sealant for liquid crystal display elements of the present invention preferably contains a silane coupling agent.
• the silane coupling agent mainly serves as an adhesion aid for providing good adhesion between the sealant for liquid crystal display elements and a substrate or the like.
• the silane coupling agent for example, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, etc. are suitably used.
• the preferred lower limit of the content of the silane coupling agent in 100 parts by mass of the sealant for liquid crystal display elements of the present invention is 0.1 parts by mass, and the preferred upper limit is 10 parts by mass.
• the resulting sealant for liquid crystal display elements has an excellent effect of improving adhesion while suppressing the occurrence of liquid crystal contamination.
• a more preferred lower limit of the content of the silane coupling agent is 0.3 parts by mass, and a more preferred upper limit is 5 parts by mass.
• the sealant for liquid crystal display elements of the present invention may further contain additives such as stress relaxation agents, reactive diluents, curing accelerators, defoamers, leveling agents, and polymerization inhibitors, as necessary.
• the method for producing the sealing agent for liquid crystal display elements of the present invention may be, for example, a method in which a curable resin, an inorganic filler, and other components such as a photopolymerization initiator are mixed using a mixer.
• the mixer include a homodisper, a homomixer, a universal mixer, a planetary mixer, a kneader, and a three-roll mixer.
• a vertically conductive material can be produced.
• the conductive fine particles may be metal balls, fine resin particles having a conductive metal layer formed on the surface thereof, etc. Among them, fine resin particles having a conductive metal layer formed on the surface thereof are preferable because the excellent elasticity of the fine resin particles allows conductive connection without damaging a transparent substrate, etc.
• a liquid crystal dropping method is suitably used, and specifically, for example, a method having the following steps can be mentioned.
• a process is performed in which the sealant for liquid crystal display elements of the present invention is applied by screen printing, dispenser application, or the like to one of two transparent substrates having electrodes such as ITO thin films to form a frame-shaped seal pattern.
• a process is performed in which minute droplets of liquid crystal are dropwise applied to the entire inside of the frame of the seal pattern, and the other transparent substrate is superimposed under vacuum.
• a liquid crystal display element can be obtained by a process of irradiating the seal pattern portion with light such as ultraviolet light to temporarily cure the sealant (photocuring process), and a process of heating the temporarily cured sealant to completely cure it (thermal curing process).
• the present invention provides a sealant for liquid crystal display elements that is excellent in transparency, adhesion, and moisture permeability prevention.
• a glass reactor with an internal volume of 10 L equipped with a stirrer was filled with 2.5 L of methanol, and 500 g of an aqueous ammonia solution (concentration 25% by mass) was added to prepare an ammoniacal methanol solution.
• the mixed solution of tetraethyl silicate hydrolyzate and tetrabutyl titanate prepared above was added to the obtained ammoniacal methanol solution over about 2 hours while maintaining the temperature of the reaction vessel at 20°C.
• the reaction solution turned milky white within a few minutes after the start of addition.
• stirring was continued for another hour, the solvent was removed from the milky white reaction liquid using an evaporator, and the mixture was further dried under reduced pressure at 80° C.
• silica-titania composite oxide A The refractive index of the obtained silica-titania composite oxide A at 25° C. was measured for the sodium D line by an immersion method using an Abbe refractometer (manufactured by ERMA, "Universal Abbe Refractometer ER-7MW”) and an ultraviolet-visible spectrophotometer (manufactured by Shimadzu Corporation, "UV-3101PC”), and the refractive index was 1.60.
• the average primary particle diameter of the obtained silica-titania composite oxide A was measured using a SEM-EDX measuring device (Hitachi High-Technologies Corporation, "S-4800”) and was 0.3 ⁇ m.
• a glass reactor with an internal volume of 10 L equipped with a stirrer was filled with 2.5 L of methanol, and 500 g of an aqueous ammonia solution (concentration 25% by mass) was added to prepare an ammoniacal methanol solution.
• the mixed solution of tetraethyl silicate hydrolyzate and tetrabutyl titanate prepared above was added to the obtained ammoniacal methanol solution over about 2 hours while maintaining the temperature of the reaction vessel at 20°C.
• the reaction solution turned milky white within a few minutes after the start of addition.
• stirring was continued for another hour, the solvent was removed from the milky white reaction liquid using an evaporator, and the mixture was further dried under reduced pressure at 80° C.
• silica-titania composite oxide B The refractive index of the obtained silica-titania composite oxide B with respect to the sodium D line was measured by an immersion method using an Abbe refractometer (manufactured by ERMA, "Universal Abbe Refractometer ER-7MW”) and an ultraviolet-visible spectrophotometer (manufactured by Shimadzu Corporation, "UV-3101PC”) at 25°C, and the refractive index was 1.56.
• the average primary particle size of the obtained silica-titania composite oxide B was measured using a SEM-EDX measuring device ("S-4800" manufactured by Hitachi High-Technologies Corporation) and was 0.3 ⁇ m.
• the M value of the obtained silica-titania composite oxide B was measured in the same manner as for the silica-titania composite oxide A and was 0.
• a glass reactor with an internal volume of 10 L equipped with a stirrer was filled with 2.5 L of methanol, and 500 g of an aqueous ammonia solution (concentration 25% by mass) was added to prepare an ammoniacal methanol solution.
• the mixed solution of tetraethyl silicate hydrolyzate and tetrabutyl titanate prepared above was added to the obtained ammoniacal methanol solution over about 2 hours while maintaining the temperature of the reaction vessel at 20°C.
• the reaction solution turned milky white within a few minutes after the start of addition.
• stirring was continued for another hour, the solvent was removed from the milky white reaction liquid using an evaporator, and the mixture was further dried under reduced pressure at 80° C.
• silica-titania composite oxide C The refractive index of the obtained silica-titania composite oxide C with respect to the sodium D line was measured by the immersion method using an Abbe refractometer (manufactured by ERMA, "Universal Abbe Refractometer ER-7MW”) and an ultraviolet-visible spectrophotometer (manufactured by Shimadzu Corporation, "UV-3101PC") at 25°C, and the refractive index was 1.50.
• the average primary particle size of the obtained silica-titania composite oxide C was measured using a SEM-EDX measuring device ("S-4800" manufactured by Hitachi High-Technologies Corporation) and was 0.3 ⁇ m.
• the M value of the obtained silica-titania composite oxide C was measured in the same manner as for the silica-titania composite oxide A and was 0.
• a glass reactor with an internal volume of 10 L equipped with a stirrer was filled with 2.5 L of methanol, and 500 g of an aqueous ammonia solution (concentration 25% by mass) was added to prepare an ammoniacal methanol solution.
• the mixed solution of tetraethyl silicate hydrolyzate and tetrabutyl titanate prepared above was added to the obtained ammoniacal methanol solution over about 2 hours while maintaining the temperature of the reaction vessel at 20°C.
• the reaction solution turned milky white within a few minutes after the start of addition.
• stirring was continued for another hour, the solvent was removed from the milky white reaction liquid using an evaporator, and the mixture was further dried under reduced pressure at 80° C.
• silica-titania composite oxide 10 parts by mass of the obtained silica-titania composite oxide was dispersed in 100 parts by mass of an ethanol solution in which 5 parts by mass of methyltriethoxysilane was dissolved, and the mixture was reacted for 1 hour under reflux of ethanol to obtain a surface-treated silica-titania composite oxide D having methyl groups on the surface as hydrophobic groups.
• the refractive index of the obtained surface-treated silica-titania composite oxide D was measured at 25° C.
• the average primary particle size of the obtained surface-treated silica-titania composite oxide D was measured using a SEM-EDX measuring device ("S-4800” manufactured by Hitachi High-Technologies Corporation) and was 0.3 ⁇ m. Furthermore, the M value of the obtained surface-treated silica-titania composite oxide D was measured in the same manner as for the above-mentioned silica-titania composite oxide A and was 31.
• Examples 1 to 10 and Comparative Examples 1 to 4 According to the compounding ratios shown in Table 1, each material was mixed using a planetary mixer, and then further mixed using a three-roll mill to prepare sealants for liquid crystal display elements in Examples 1 to 10 and Comparative Examples 1 to 4.
• Awatori Mixer (Thinky Corporation) was used as the planetary mixer.
• the UV irradiator used was MB1500T-3 (manufactured by Sen Special Light Sources Co., Ltd.), and the spectrometer used was AUTOMATIC HAZE METER MODEL TC-III DPK (manufactured by Tokyo Denshoku Co., Ltd.). The results are shown in Table 1.
• the obtained sealant for liquid crystal display elements was applied onto a smooth release film using a coater.
• the applied sealant was irradiated with ultraviolet light having a wavelength of 365 nm and an illuminance of 100 mW/ cm2 for 30 seconds using a UV irradiator through a 340 nm cut filter, and then heated at 120°C for 60 minutes to obtain a cured product (thickness 300 ⁇ m).
• MB1500T-3 manufactured by Sen Special Light Source Co., Ltd. was used as the UV irradiator.
• a moisture permeability test cup was prepared according to the moisture permeability test method for moisture-proof packaging materials (cup method) of JIS Z 0208, and the obtained cured product was attached to the cup, which was then placed in a constant temperature and humidity oven at 80°C and 90% RH to measure the moisture permeability. The results are shown in Table 1.
• the obtained sealant for liquid crystal display devices was dotted on one of the two glass substrates so that the diameter of the substrates when bonded together was 3 mm.
• the glass substrate with the dotted sealant and the other glass substrate were bonded together in a cross shape via the sealant.
• ultraviolet light with a wavelength of 365 nm and an illuminance of 100 mW/cm 2 was irradiated through a 340 nm cut filter for 30 seconds, and then heated at 120°C for 60 minutes to harden the sealant, thereby obtaining a test piece.
• MB1500T-3 manufactured by Sen Special Light Source Co., Ltd.
• the obtained test piece was subjected to a tensile test at 5 mm/sec with chucks arranged above and below in an environment of 25°C, to measure the adhesive strength to glass. The results are shown in Table 1.
• the obtained curable resin composition was irradiated with ultraviolet light having a wavelength of 365 nm and an illuminance of 100 mW/cm 2 through a 340 nm cut filter for 30 seconds using a UV irradiator, and then heated at 120 ° C. for 60 minutes to obtain a cured product.
• MB1500T-3 manufactured by Sen Special Light Source Co., Ltd.
• the refractive index of the obtained cured product with respect to the sodium D line was measured at 25 ° C. using an Abbe refractometer (manufactured by ERMA, "Universal Abbe Refractometer ER-7MW"). The results are shown in Table 1.
• the adhesion to glass was evaluated by assigning an "A” to an adhesive strength measured in the above “(Measurement of adhesive strength to glass)” that was 2.3 kgf/cm or more, an “O” to an adhesive strength measured in the same manner as above, but less than 2.0 kgf/cm, and an "X” to an adhesive strength measured in the same manner as above.
• the adhesion to the alignment film was evaluated by assigning an " ⁇ " to a case where the adhesive strength measured in the above “(Measurement of adhesive strength to alignment film)" was 1.5 kgf/cm or more, an " ⁇ ” to a case where the adhesive strength was 1.0 kgf/cm or more and less than 1.5 kgf/cm, and an " ⁇ " to a case where the adhesive strength was less than 1.0 kgf/cm.
• the moisture permeability prevention was evaluated as follows : when the moisture permeability measured in the above "(Measurement of moisture permeability)" was 80 g/ m2 ⁇ 24hr or less, it was marked “ ⁇ ", when it was more than 80 g/ m2 ⁇ 24hr and 85 g/ m2 ⁇ 24hr or less, it was marked “ ⁇ ”, when it was more than 85 g/ m2 ⁇ 24hr and 90 g/m2 ⁇ 24hr or less, it was marked “ ⁇ ", and when it exceeded 90 g/ m2 ⁇ 24hr, it was marked "X”.
• the present invention provides a sealant for liquid crystal display elements that is excellent in transparency, adhesion, and moisture permeability prevention.

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