Sealing agent for liquid crystal device

Abstract

To provide a sealing agent for a liquid crystal device which is excellent in storage stability, low temperature curability, insertion prevention, and low liquid crystal contamination.SOLUTION: A sealing agent for a liquid crystal device contains a curable resin, an acid anhydride, and a base generator, wherein the base generator generates a tertiary amine compound by heating or irradiation with active energy rays.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a sealant for a liquid crystal device. [Background technology]

[0002] In recent years, liquid crystal display elements have been widely used as display elements characterized by their thinness, light weight, low power consumption, etc. Furthermore, liquid crystal light control elements using liquid crystal materials are widely used as light control elements whose light transmittance changes when a voltage is applied. In such liquid crystal devices as liquid crystal display elements and liquid crystal light control elements, sealants are usually used for bonding various components and sealing the liquid crystal.

[0003] For example, as a method for manufacturing liquid crystal display elements, a liquid crystal dropping method using a sealant, known as a dropping method, as disclosed in Patent Documents 1 and 2, is used from the viewpoint of shortening takt time and optimizing the amount of liquid crystal used. In the dropping method, a frame-shaped seal pattern is first formed by dispensing on one of two electrode-attached substrates. Next, while the sealant is still in an uncured state, tiny droplets of liquid crystal are dropped into the frame of the seal pattern. After the other substrate is placed on top of the other substrate under vacuum, the sealant is cured to create a liquid crystal display element. This dropping method is currently the mainstream method for manufacturing liquid crystal display elements.

[0004] Furthermore, for example, Patent Document 3 discloses the use of a material containing an epoxy compound as a sealant that surrounds the liquid crystal layer of a light control unit.

[0005] Nowadays, with the widespread use of mobile devices with various liquid crystal panels, such as mobile phones and portable game consoles, miniaturization of devices is a major issue. One method for miniaturizing devices is to narrow the frame of the display, for example, by locating the seal under the black matrix (hereinafter also referred to as a narrow frame design). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-133794 [Patent Document 2] International Publication No. 02 / 092718 [Patent Document 3] Patent Publication No. 2021-117456 Summary of the Invention [Problem to be solved by the invention]

[0007] Conventionally, sealants for liquid crystal devices have been widely used, containing an epoxy compound and an amine-based thermosetting agent for curing the epoxy compound. In recent years, from the perspective of environmental, social, and governance (ESG) activities and the need to accommodate substrates with low heat resistance, curing sealants by heating at low temperatures, such as 80°C or below, has been considered. However, if the sealant is not cured sufficiently by heating at low temperatures, problems arise, such as liquid crystals that flow during heating, such as liquid crystal annealing, penetrating into the sealant, causing disruption or tearing of the seal pattern, or contamination of the liquid crystal by the sealant. In particular, in recent years, narrow frame designs have led to thinner lines of applied sealant, making liquid crystal penetration more likely. One method for improving the low-temperature curing properties of sealants is to use a thermosetting agent with excellent low-temperature reactivity. However, using a thermosetting agent with excellent low-temperature reactivity results in the sealant having poor storage stability.

[0008] An object of the present invention is to provide a sealant for liquid crystal devices that has excellent storage stability, low-temperature curing properties, penetration prevention properties, and low liquid crystal contamination properties. [Means for solving the problem]

[0009] Disclosure 1 relates to a sealant for liquid crystal devices, which contains a curable resin, an acid anhydride, and a base generator, and the base generator generates a tertiary amine compound upon heating or irradiation with active energy rays. Disclosure 2 is the sealant for a liquid crystal device according to Disclosure 1, wherein the curable resin contains an epoxy compound. Disclosure 3 is the sealant for a liquid crystal device according to Disclosure 1 or 2, wherein the curable resin contains a (meth)acrylic compound. The present disclosure 4 is the sealant for a liquid crystal device according to the present disclosure 1, 2 or 3, wherein the content of the base generator relative to 100 parts by mass of the curable resin is 0.2 parts by mass or more and 4.0 parts by mass or less. The present disclosure 5 is the sealant for liquid crystal devices according to the present disclosure 1, 2, 3 or 4, wherein the content of the base generator is 0.5 parts by mass or more and 12.0 parts by mass or less based on 100 parts by mass of the total of the acid anhydride and the base generator. The present invention will be described in detail below.

[0010] The present inventors have found that a sealant for liquid crystal devices that is excellent in storage stability, low-temperature curing properties, resistance to insertion, and low liquid crystal contamination can be obtained by using a combination of an acid anhydride and a base generator that generates a tertiary amine compound upon heating or irradiation with active energy rays, and have thus completed the present invention.

[0011] The sealant for a liquid crystal device of the present invention contains a curable resin. The curable resin preferably contains an epoxy compound.

[0012] Examples of the epoxy compound include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol E 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, o-cresol 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 epoxy compounds, and glycidyl ester compounds.

[0013] Commercially available examples of the bisphenol A epoxy compounds include jER828EL and jER1004 (both manufactured by Mitsubishi Chemical Corporation), and EPICLON850 (manufactured by DIC Corporation). Commercially available examples of the bisphenol F epoxy compounds include jER806 and jER4004 (both manufactured by Mitsubishi Chemical Corporation), EPICLON EXA-830CRP (manufactured by DIC Corporation), and the like. Among the above bisphenol E type epoxy compounds, a commercially available example is Epomic R710 (manufactured by Mitsui Chemicals, Inc.). Among the above bisphenol S type epoxy compounds, commercially available examples include EPICLON EXA-1514 (manufactured by DIC Corporation). Among the above 2,2'-diallylbisphenol A type epoxy compounds, a commercially available one is, for example, RE-810NM (manufactured by Nippon Kayaku Co., Ltd.). Among the hydrogenated bisphenol epoxy compounds, commercially available examples include EPICLON EXA-7015 (manufactured by DIC Corporation). Among the above propylene oxide-added bisphenol A type epoxy compounds, commercially available ones include, for example, EP-4000S (manufactured by ADEKA Corporation). Among the resorcinol type epoxy compounds, commercially available examples include EX-201 (manufactured by Nagase ChemteX Corporation). Among the biphenyl type epoxy compounds, commercially available examples include jER YX-4000H (manufactured by Mitsubishi Chemical Corporation). Among the sulfide-type epoxy compounds, a commercially available example is YSLV-50TE (manufactured by Nippon Steel Chemical & Material Co., Ltd.). Among the diphenyl ether type epoxy compounds, commercially available ones include, for example, YSLV-80DE (manufactured by Nippon Steel Chemical & Material Co., Ltd.). Among the dicyclopentadiene type epoxy compounds, commercially available ones include, for example, EP-4088S (manufactured by ADEKA Corporation). Among the above naphthalene type epoxy compounds, commercially available examples include EPICLON HP-4032 and EPICLON EXA-4700 (both manufactured by DIC Corporation). Among the above phenol novolac type epoxy compounds, commercially available ones include, for example, EPICLON N-770 (manufactured by DIC Corporation). Among the above ortho-cresol novolac epoxy compounds, commercially available examples include EPICLON N-670-EXP-S (manufactured by DIC Corporation). Among the dicyclopentadiene novolac epoxy compounds, commercially available examples include EPICLON HP-7200 (manufactured by DIC Corporation). Among the biphenyl novolac epoxy compounds, commercially available examples include NC-3000P (manufactured by Nippon Kayaku Co., Ltd.). Among the above naphthalenephenol novolac type epoxy compounds, commercially available examples include ESN-165S (manufactured by Nippon Steel Chemical & Material Co., Ltd.). Commercially available examples of the glycidylamine type epoxy compounds include jER630 (manufactured by Mitsubishi Chemical Corporation), EPICLON430 (manufactured by DIC Corporation), and TETRAD-X (manufactured by Mitsubishi Gas Chemical Company, Inc.). Commercially available examples of the alkyl polyol epoxy compounds include ZX-1542 (manufactured by Nippon Steel Chemical & Material Co., Ltd.), EPICLON726 (manufactured by DIC Corporation), Epolite 80MFA (manufactured by Kyoeisha Chemical Co., Ltd.), and Denacol EX-611 (manufactured by Nagase ChemteX Corporation). Among the rubber-modified epoxy compounds, commercially available examples include YR-450 and YR-207 (both manufactured by Nippon Steel Chemical & Material Co., Ltd.), Epolead PB (manufactured by Daicel Corporation), and the like. Among the above glycidyl ester compounds, commercially available examples include 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.).

[0014] As the epoxy compound, a partially (meth)acrylic-modified epoxy compound can also be suitably used. In this specification, the partially (meth)acrylic-modified epoxy compound refers to a compound having one or more epoxy groups and one or more (meth)acryloyl groups in one molecule, which can be obtained by reacting a portion of the epoxy groups of an epoxy compound having two or more epoxy groups with (meth)acrylic acid. In this specification, the term "(meth)acrylic" means acrylic or methacrylic, and the term "(meth)acryloyl" means acryloyl or methacryloyl.

[0015] Among the above partially (meth)acrylic modified epoxy compounds, commercially available ones include, for example, UVACURE1561 and EBECRYL3605.

[0016] The epoxy compound content in 100 parts by mass of the curable resin is preferably 1 part by mass at its lower limit and 50 parts by mass at its upper limit. By ensuring that the epoxy compound content falls within this range, the resulting sealant for liquid crystal devices will have superior curability, adhesive properties, and low liquid crystal contamination. The epoxy compound content is more preferably 5 parts by mass at its lower limit and 45 parts by mass at its upper limit.

[0017] The curable resin preferably contains a (meth)acrylic compound. Examples of the (meth)acrylic compound include (meth)acrylic acid ester compounds, epoxy (meth)acrylates, and urethane (meth)acrylates. Of these, epoxy (meth)acrylates are preferred. From the viewpoint of reactivity, the (meth)acrylic compound preferably has two or more (meth)acryloyl groups in one molecule. In this specification, the term "(meth)acrylic compound" refers to a compound having a (meth)acryloyl group, excluding the partially (meth)acrylic-modified epoxy compound. The term "(meth)acrylate" refers to an acrylate or methacrylate, and the term "epoxy (meth)acrylate" refers to a compound in which all epoxy groups in an epoxy compound have reacted with (meth)acrylic acid.

[0018] Examples of the 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, and isononyl (meth)acrylate. Myristyl (meth)acrylate, stearyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, bicyclopentenyl (meth)acrylate, benzyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2 -Butoxyethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, methoxyethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, ethyl carbitol (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl Examples of the acrylates include 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl hexahydrophthalate, 2-(meth)acryloyloxyethyl 2-hydroxypropyl phthalate, 2-(meth)acryloyloxyethyl phosphate, and glycidyl (meth)acrylate.

[0019] Furthermore, 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 suitable bisphenol A di(meth)acrylates include butyl di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethylene oxide-added bisphenol A di(meth)acrylate, propylene oxide-added bisphenol A di(meth)acrylate, ethylene oxide-added bisphenol F di(meth)acrylate, dimethyloldicyclopentadienyl di(meth)acrylate, ethylene oxide-modified isocyanuric acid di(meth)acrylate, 2-hydroxy-3-(meth)acryloyloxypropyl (meth)acrylate, carbonate diol di(meth)acrylate, polyether diol di(meth)acrylate, polyester diol di(meth)acrylate, polycaprolactone diol di(meth)acrylate, and polybutadiene diol di(meth)acrylate.

[0020] Furthermore, 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, and dipentaerythritol hexa(meth)acrylate.

[0021] The epoxy (meth)acrylate may be, for example, one obtained by reacting an epoxy compound with (meth)acrylic acid in the presence of a basic catalyst according to a conventional method.

[0022] Examples of the epoxy compound that serves as a raw material for synthesizing the epoxy (meth)acrylate include the epoxy compounds exemplified above as those that are preferably contained in the curable resin.

[0023] Among the above-mentioned 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, EBECRYL RDX63182, and KRM8076. 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.

[0024] The urethane (meth)acrylate can be obtained, for example, by reacting an isocyanate compound with a (meth)acrylic acid derivative having a hydroxyl group in the presence of a catalytic amount of a tin compound.

[0025] Examples of isocyanate compounds that can be used as raw materials for the urethane (meth)acrylate 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.

[0026] Furthermore, as the isocyanate compound that is the raw material for the urethane (meth)acrylate, a chain-extended isocyanate compound obtained by reacting a polyol with an excess of an isocyanate compound can also be used. Examples of the polyol include ethylene glycol, propylene glycol, glycerin, sorbitol, trimethylolpropane, carbonate diol, polyether diol, polyester diol, and polycaprolactone diol.

[0027] Examples of the (meth)acrylic acid derivative having a hydroxyl group include hydroxyalkyl mono(meth)acrylate, mono(meth)acrylate of a dihydric alcohol, mono(meth)acrylate or di(meth)acrylate of a trihydric alcohol, and epoxy(meth)acrylate. 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. Examples of the epoxy(meth)acrylate include bisphenol A type epoxy(meth)acrylate.

[0028] Among the above-mentioned 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, 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. Examples of urethane (meth)acrylates manufactured by Negami Chemical Industrial Co., Ltd. include Art Resin UN-330, Art Resin SH-500B, Art Resin UN-1200TPK, Art Resin UN-1255, Art Resin UN-3320HB, Art Resin UN-7100, Art Resin UN-9000A, and Art Resin UN-9000H. Examples of the urethane (meth)acrylates manufactured by Shin-Nakamura Chemical Co., Ltd. include U-2HA, U-2PHA, U-3HA, U-4HA, U-6H, U-6HA, U-6LPA, U-10H, U-15HA, U-108, U-108A, U-122A, U-122P, U-324A, U-340A, U-340P, U-1084A, U-2061BA, UA-340P, UA-4000, UA-4100, UA-4200, UA-4400, UA-5201P, UA-7100, UA-7200, and UA-W2A. Examples of the 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.

[0029] The preferred lower limit of the content of the (meth)acrylic compound in 100 parts by mass of the curable resin is 1 part by mass, and the preferred upper limit is 95 parts by mass. By ensuring that the content of the (meth)acrylic compound is within this range, the resulting sealant for liquid crystal devices will have better curability, adhesion, and reduced liquid crystal contamination. The more preferred lower limit of the content of the (meth)acrylic compound is 5 parts by mass, and the more preferred upper limit is 50 parts by mass.

[0030] When the epoxy compound and the (meth)acrylic compound are used in combination as the curable resin, or when the partially (meth)acrylic-modified epoxy compound is used, the ratio of (meth)acryloyl groups in the total of epoxy groups and (meth)acryloyl groups in the curable resin is preferably 30 mol % or more and 95 mol % or less. When the ratio of (meth)acryloyl groups is within this range, the resulting sealant for liquid crystal devices has excellent adhesion while suppressing the occurrence of liquid crystal contamination.

[0031] From the viewpoint of further suppressing contamination of the liquid crystal, the curable resin preferably has a hydrogen-bonding unit such as an -OH group, an -NH- group, or an -NH2 group.

[0032] The preferred lower limit of the total content of the curable resins in 100 parts by mass of the sealant for liquid crystal devices of the present invention is 50 parts by mass, and the preferred upper limit is 95 parts by mass. When the total content of the curable resins is within this range, the resulting sealant for liquid crystal devices will have better curability and adhesiveness.

[0033] The sealing agent for a liquid crystal device of the present invention contains an acid anhydride. The acid anhydride mainly functions as a heat curing agent. By containing the above acid anhydride in combination with a specific base generator described below, the sealant for liquid crystal devices of the present invention becomes excellent in storage stability, low-temperature curing property, anti-penetration property, and low liquid crystal contamination.

[0034] Examples of the acid anhydride include 4-methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, 4,4-oxydiphthalic anhydride, phthalic pyromellitic anhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, and mixtures of two or more of these compounds. Among these, 4-methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, 4,4-oxydiphthalic anhydride, and mixtures of two or more of these compounds are preferred.

[0035] The preferred lower limit of the content of the acid anhydride per 100 parts by mass of the curable resin is 1 part by mass, and the preferred upper limit is 50 parts by mass. By ensuring that the content of the acid anhydride is within this range, the resulting sealant for liquid crystal devices will have better storage stability, low-temperature curing properties, resistance to penetration, and low liquid crystal contamination. The more preferred lower limit of the content of the acid anhydride is 5 parts by mass, and the more preferred upper limit is 45 parts by mass.

[0036] The sealing agent for a liquid crystal device of the present invention contains a base generator. The base generator generates a tertiary amine compound upon heating or irradiation with active energy rays. Hereinafter, the base generator that generates a tertiary amine compound upon heating or irradiation with active energy rays is also referred to as the "base generator according to the present invention." By containing the base generator according to the present invention in combination with the acid anhydride, the sealant for liquid crystal devices of the present invention becomes excellent in storage stability, low-temperature curing property, anti-penetration property, and low liquid crystal contamination. In this specification, the term "tertiary amine compound" refers to a compound having a tertiary amine structure (tertiary amino group), and may have a primary amine structure or a secondary amine structure as long as it has the tertiary amine structure. The tertiary amine structure may be included in a cyclic structure.

[0037] The base generator according to the present invention is preferably a photobase generator that generates a tertiary amine compound upon irradiation with light. Furthermore, the thermal base generator that generates a tertiary amine compound upon heating is preferably a thermal base generator that generates a tertiary amine compound at a temperature of 80°C or less. Specifically, the base generator according to the present invention is preferably a salt represented by the following formula (1), a salt represented by the following formula (2), or a salt represented by the following formula (3), more preferably a salt represented by the following formula (1) or a salt represented by the following formula (2), and even more preferably a salt represented by the following formula (1). The salt represented by the following formula (1) is a photobase generator that generates the tertiary amine compound 1-(bis(dimethylamino)methylene)-2,3-diisopropylguanidine upon irradiation with light. The salt represented by the following formula (2) is a thermal base generator that generates the tertiary amine compound 1,8-diazabicyclo[5.4.0]undecene-7 upon heating at approximately 80°C. The salt represented by the following formula (3) is a thermal base generator that generates the tertiary amine compound 1,8-diazabicyclo[5.4.0]undecene-7 upon heating at approximately 100°C.

[0038] [ka]

[0039] [ka]

[0040] [ka]

[0041] The preferred lower limit of the content of the base generator according to the present invention relative to 100 parts by mass of the curable resin is 0.2 parts by mass, and the preferred upper limit is 4.0 parts by mass. When the content of the base generator according to the present invention relative to 100 parts by mass of the curable resin is within this range, the resulting sealant for liquid crystal devices will have better storage stability, low-temperature curing properties, resistance to insertion, and low liquid crystal contamination. The more preferred lower limit of the content of the base generator according to the present invention relative to 100 parts by mass of the curable resin is 0.5 parts by mass, and the more preferred upper limit is 2.0 parts by mass.

[0042] Furthermore, the preferred lower limit of the content of the base generator according to the present invention in a total of 100 parts by mass of the acid anhydride and the base generator according to the present invention is 0.5 parts by mass, and the preferred upper limit is 12.0 parts by mass. When the content of the base generator according to the present invention in a total of 100 parts by mass of the acid anhydride and the base generator according to the present invention is within this range, the resulting sealant for liquid crystal devices will have better storage stability, low-temperature curing properties, resistance to insertion, and low liquid crystal contamination. The more preferred lower limit of the content of the base generator according to the present invention in a total of 100 parts by mass of the acid anhydride and the base generator according to the present invention is 1.6 parts by mass, and the more preferred upper limit is 11.5 parts by mass, the even more preferred upper limit is 10.0 parts by mass, and the even more preferred upper limit is 6.1 parts by mass.

[0043] The sealing agent for a liquid crystal device of the present invention preferably contains a photopolymerization initiator. In particular, when the curable resin contains the (meth)acrylic compound, the photopolymerization initiator is preferably a photoradical polymerization initiator.

[0044] Examples of the photoradical polymerization initiator include benzophenone compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, oxime ester compounds, benzoin ether compounds, and thioxanthone compounds. Specific examples of the photopolymerization initiator 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-methylphenyl)-1-butanone ...

[0033] Examples of such oxime include 1-(4-(phenylthiophenyl)-2-morpholinopropan-1-one, 1-(4-(2-hydroxyethoxy)-phenyl)-2-hydroxy-2-methyl-1-propan-1-one, 1-(4-(phenylthio)phenyl)-1,2-octanedione 2-(O-benzoyloxime), 2-(acetoxyimino)-1-(4-(4-(2-hydroxyethoxy)phenylthio)phenyl)propan-1-one, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide.

[0045] The preferred lower limit of the content of the photopolymerization initiator relative to 100 parts by mass of the curable resin is 0.1 parts by mass, and the preferred upper limit is 10 parts by mass. By using a photopolymerization initiator in this range, the resulting sealant for liquid crystal devices exhibits excellent storage stability and photocurability while suppressing the occurrence of liquid crystal contamination. The more preferred lower limit of the content of the photopolymerization initiator is 0.3 parts by mass, and the more preferred upper limit is 5 parts by mass.

[0046] The sealing agent for a liquid crystal device of the present invention may contain a thermal polymerization initiator. In particular, when the curable resin contains the (meth)acrylic compound, the thermal polymerization initiator is preferably a thermal radical polymerization initiator.

[0047] Examples of the thermal radical polymerization initiator include those composed of an azo compound, an organic peroxide, etc. Among them, from the viewpoint of suppressing contamination of the liquid crystal, an initiator composed of an azo compound (hereinafter also referred to as "azo initiator") is preferred. The thermal radical polymerization initiators may be used alone or in combination of two or more.

[0048] Examples of the azo compound include 2,2'-azobis(2,4-dimethylvaleronitrile), 4,4'-azobis(4-cyanovaleric acid), 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. Examples of the azo initiator include VPE-0201, VPE-0401, VPE-0601, VPS-0501, VPS-1001, V-65, and V-501 (all manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.).

[0049] Examples of the organic peroxide include ketone peroxides, peroxyketals, hydroperoxides, dialkyl peroxides, peroxyesters, diacyl peroxides, and peroxydicarbonates.

[0050] The preferred lower limit of the content of the thermal polymerization initiator relative to 100 parts by mass of the curable resin is 0.1 parts by mass, and the preferred upper limit is 10 parts by mass. By ensuring that the content of the thermal polymerization initiator is within this range, the resulting sealant for liquid crystal devices exhibits excellent storage stability and thermosetting properties while suppressing the occurrence of liquid crystal contamination. The more preferred lower limit of the content of the thermal polymerization initiator is 0.3 parts by mass, and the more preferred upper limit is 5 parts by mass.

[0051] The sealant for a liquid crystal device of the present invention may contain a filler for the purposes of adjusting viscosity, improving adhesion by a stress dispersion effect, improving the linear expansion coefficient, and improving the moisture resistance of the cured product.

[0052] As the filler, inorganic fillers and organic fillers can be used. Examples of the inorganic filler include silica, talc, glass beads, asbestos, gypsum, diatomaceous earth, smectite, bentonite, montmorillonite, sericite, activated clay, alumina, zinc oxide, iron oxide, magnesium oxide, tin oxide, titanium oxide, calcium carbonate, magnesium carbonate, magnesium hydroxide, aluminum hydroxide, aluminum nitride, silicon nitride, barium sulfate, and calcium silicate. Examples of the organic filler include polyester fine particles, polyurethane fine particles, vinyl polymer fine particles, and acrylic polymer fine particles.

[0053] The preferred lower limit of the filler content per 100 parts by mass of the curable resin is 10 parts by mass, and the preferred upper limit is 70 parts by mass. By having the filler content within this range, excellent effects such as improved adhesion can be achieved without deteriorating the coating properties, etc. The more preferred lower limit of the filler content is 20 parts by mass, and the more preferred upper limit is 60 parts by mass.

[0054] The sealant for a liquid crystal device of the present invention may contain a silane coupling agent. The silane coupling agent mainly serves as an adhesion aid for favorable adhesion between the sealant for a liquid crystal device and a substrate or the like.

[0055] Suitable examples of the silane coupling agent include 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-isocyanatopropyltrimethoxysilane. These are effective in improving adhesion to substrates and can suppress the outflow of the curable resin into the liquid crystal by chemically bonding with the curable resin. Of these, 3-glycidoxypropyltrimethoxysilane is preferred.

[0056] The preferred lower limit of the content of the silane coupling agent relative to 100 parts by mass of the curable resin is 0.1 parts by mass, and the preferred upper limit is 10 parts by mass. By using the silane coupling agent in this range, the resulting sealant for liquid crystal devices will have excellent adhesion while suppressing the occurrence of liquid crystal contamination. The more preferred lower limit of the content of the silane coupling agent is 0.3 parts by mass, and the more preferred upper limit is 5 parts by mass.

[0057] The sealing agent for liquid crystal devices of the present invention may further contain additives such as a stress relaxation agent, a reactive diluent, a thixotropic agent, a spacer, a curing accelerator, an antifoaming agent, a leveling agent, a polymerization inhibitor, and a light-blocking agent, as necessary.

[0058] Examples of a method for producing the sealing agent for liquid crystal devices of the present invention include a method of mixing a curable resin, an acid anhydride, the base generator of the present invention, and a photopolymerization initiator or the like that is added as needed using a mixer. Examples of the mixer include a homodisper, a homomixer, a universal mixer, a planetary mixer, a kneader, and a three-roll mixer.

[0059] By blending conductive fine particles into the sealant for liquid crystal devices of the present invention, a vertically conductive material can be produced. The conductive fine particles may be, for example, metal balls, fine resin particles with a conductive metal layer formed on the surface thereof, etc. Among these, fine resin particles with a conductive metal layer formed on the surface thereof are preferred because they can achieve conductive connection without damaging transparent substrates, etc., due to the excellent elasticity of the fine resin particles.

[0060] The liquid crystal device manufactured using the sealant for a liquid crystal device of the present invention is preferably a liquid crystal device with a narrow frame design, specifically, the width of the frame around the liquid crystal display unit is preferably 2 mm or less. Furthermore, when the liquid crystal device is produced, the application width of the sealant for a liquid crystal device of the present invention is preferably 1 mm or less.

[0061] The sealant for a liquid crystal device of the present invention can be suitably used in the production of a liquid crystal device by a liquid crystal dropping method. Examples of the method for producing a liquid crystal device by the liquid crystal dropping method include the following methods. First, a process is performed in which the sealant for liquid crystal devices of the present invention is applied to a substrate by screen printing, dispenser application, or the like to form a frame-shaped seal pattern. Next, a process is performed in which, while the sealant for liquid crystal devices of the present invention is still uncured, minute droplets of liquid crystal are dropwise applied to the entire surface within the frame of the seal pattern, and another substrate is immediately superimposed on the substrate. A liquid crystal device can then be obtained by a method in which the sealant is heated and cured. Furthermore, a process of temporarily curing the sealant by irradiating the seal pattern with light such as ultraviolet light may be performed before the process of heating and curing the sealant.

[0062] Examples of liquid crystal devices produced using the sealant for liquid crystal devices of the present invention include liquid crystal display elements and liquid crystal light control elements. Examples of the liquid crystal light control element include a PDLC (polymer dispersed liquid crystal) light control element and a guest-host liquid crystal (GHLC) light control element. [Effects of the Invention]

[0063] According to the present invention, it is possible to provide a sealant for liquid crystal devices that is excellent in storage stability, low-temperature curing property, penetration prevention property, and low liquid crystal contamination. DETAILED DESCRIPTION OF THE INVENTION

[0064] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0065] (Examples 1 to 10, Comparative Examples 1 to 6) Each material was mixed using a planetary mixer (Thinky Corporation, "Awatori Rentaro") according to the compounding ratios shown in Tables 1 and 2, and then further mixed using a three-roll mill to prepare each of the liquid crystal device sealants of Examples 1 to 10 and Comparative Examples 1 to 6. In the table, "RIKACID MH-700" is a mixture of 4-methylhexahydrophthalic anhydride and hexahydrophthalic anhydride. In the table, "WPBG-266" is a salt represented by the above formula (1), "U-CAT SA-1" is a salt represented by the above formula (2), and "U-CAT SA-102" is a salt represented by the above formula (3). In the table, "WPBG-018" is a photobase generator represented by the following formula (4) that generates diethylamine, a secondary amine compound, upon irradiation with light.

[0066] [ka]

[0067] <Evaluation> The resulting sealant for liquid crystal devices was evaluated as follows, and the results are shown in Tables 1 and 2.

[0068] (Storage stability) The initial viscosity of the resulting sealant for liquid crystal devices was measured immediately after production, and the viscosity after storage in a -30°C freezer for two days and then thawing at 20°C to 25°C for one hour (viscosity after frozen storage). The viscosity after frozen storage divided by the initial viscosity was used as the viscosity increase ratio, and storage stability was evaluated according to the following criteria. The viscosity of the sealant for liquid crystal devices was measured using an E-type viscometer (BROOK FIELD, "DV-III") at 25°C and a rotation speed of 1.0 rpm. ◎: When the viscosity increase rate is 1.5 or less ○: When the viscosity increase rate is more than 1.5 and 1.75 or less △: When the viscosity increase rate is more than 1.75 and less than 2.0 ×: When the viscosity increase rate exceeds 2.0

[0069] (curable) The obtained sealant for liquid crystal devices was cured by heating at 80°C for 1 hour to obtain a cured product. In addition, the heating temperature was changed to 100°C and 120°C to obtain cured products. The sealant for liquid crystal devices before curing and each cured product were subjected to FT-IR analysis using a Fourier transform infrared spectrophotometer to determine the difference in the 915cm wavelength derived from the epoxy group before and after curing. -1 The reduction rate of the peak area of ​​the peak in the vicinity was calculated as the reaction rate of the epoxy group, and the curability was evaluated according to the following criteria: The Fourier transform infrared spectrophotometer used was a Nicolet iS-5 (manufactured by ThermoFisher). ○: When the reaction rate of the epoxy group is 90% or more △: When the reaction rate of the epoxy group is 75% or more but less than 90% ×: When the reaction rate of the epoxy group is less than 75%

[0070] (Plug-in prevention) One part by mass of spacer particles (Micropearl SP-2050, manufactured by Sekisui Chemical Co., Ltd.) with an average particle size of 5 μm was uniformly dispersed in 100 parts by mass of the resulting sealant for liquid crystal devices using a planetary stirrer. The sealant for liquid crystal devices with the spacer particles dispersed therein was then filled into a syringe (PSY-10EU-OR, manufactured by Musashi Engineering Co., Ltd.), degassed, and then applied to one of two transparent substrates using a dispenser (SHOTMASTER300, manufactured by Musashi Engineering Co., Ltd.) to form a frame-shaped seal pattern. Next, minute droplets of liquid crystal (JC-5004LA, manufactured by Chisso Corporation) were dropwise applied to the entire surface within the frame of the seal pattern, and the other transparent substrate was immediately bonded to the substrate. After that, a metal halide lamp was used to illuminate the seal pattern area at 100 mW / cm. 2 After irradiating the film with ultraviolet light (wavelength 365 nm) for 30 seconds, the film was heated at 80° C. for 1 hour to obtain a liquid crystal display device. The shape of the seal pattern of the obtained liquid crystal display element was observed, and the resistance to insertion was evaluated according to the following criteria. ○: When there is no distortion in the shape of the seal pattern ×: When the shape of the seal pattern is disturbed by inserting the LCD

[0071] (Low liquid crystal contamination) The liquid crystal display elements obtained in the same manner as in the above "(Intercalation prevention property)" were checked for alignment disorder using a polarizing microscope (Keyence Corporation, "VHX-5000") The alignment disorder was judged by color unevenness (display unevenness) of the display area, and the low liquid crystal contamination property was evaluated according to the following criteria. ○: No alignment disorder was observed ×: When alignment disorder is confirmed

[0072] [Table 1]

[0073] [Table 2] [Industrial Applicability]

[0074] According to the present invention, it is possible to provide a sealant for liquid crystal devices that is excellent in storage stability, low-temperature curing property, penetration prevention property, and low liquid crystal contamination.

Claims

1. The composition contains a curable resin, an acid anhydride, and a base generator, The base generator generates a tertiary amine compound upon heating or irradiation with active energy rays. A sealant for a liquid crystal device.

2. 2. The sealant for a liquid crystal device according to claim 1, wherein the curable resin contains an epoxy compound.

3. 3. The sealant for a liquid crystal device according to claim 1, wherein the curable resin contains a (meth)acrylic compound.

4. 3. The sealant for a liquid crystal device according to claim 1, wherein the content of the base generator relative to 100 parts by mass of the curable resin is 0.2 parts by mass or more and 4.0 parts by mass or less.

5. 3. The sealant for liquid crystal devices according to claim 1, wherein the content of the base generator is 0.5 parts by mass or more and 12.0 parts by mass or less based on 100 parts by mass of the total of the acid anhydride and the base generator.

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