Sealing agent for liquid crystal display element

Abstract

The purpose of the present invention is to provide a sealing agent for a liquid crystal display element that has excellent moisture permeation resistance and adhesion to an alignment film, and in which peeling of the photocured material is suppressed even when the sealing agent is applied to a large substrate. The present invention is a sealing agent for a liquid crystal display element containing a curable resin and a photopolymerization initiator, wherein the curable resin includes a compound represented by formula (1), and the compression shear strength, with respect to a polyimide, of a 5.0-µm-thick cured material of the sealing agent for a liquid crystal display element is 15 kgf / cm2, the compression shear strength being measured in accordance with JIS K 6852 under conditions of a temperature of 25°C and a shear rate of 1 mm / sec, and the cured material being obtained by irradiation at 3000 mJ / cm2 with ultraviolet rays having a wavelength of 365 nm. In formula (1), R1 represents a hydrogen atom or a methyl group, R2 represents a group represented by formula (2-1), (2-2), or (2-3), R3 represents a methylene group, a methylmethylene group, a dimethylmethylene group, or a sulfonyl group, X represents a lactone ring-opening structure, and n is 1 to 5. In formulae (2-1) to (2-3), * represents a bonding position; in formula (2-2), a is an integer of 1-8; and in formula (2-3), b is an integer of 1-8, c is an integer of 1-3, and d is an integer of 1-8.

Description

Sealant for LCD devices

[0001] The present invention relates to a sealant for liquid crystal display elements that has excellent adhesion to alignment films and moisture-proofing properties, and that can suppress peeling after photocuring even when applied to large substrates.

[0002] In recent years, a liquid crystal dropping method known as a dropping method using a photo- and heat-curing sealant containing a curable resin, a photopolymerization initiator, and a heat-curing agent has been used as a method for manufacturing liquid crystal display elements, from the viewpoint of shortening takt time and optimizing the amount of liquid crystal used, as disclosed in Patent Documents 1 and 2.

[0003] In recent years, a method known as the "dropping method," which uses a curable resin composition as a sealant, as disclosed in Patent Documents 1 and 2, has been adopted as a manufacturing method for liquid crystal display elements such as liquid crystal display cells, from the viewpoints of shortening takt time and optimizing the amount of liquid crystal used. In the dropping method, a sealant is first applied to one of two electrode-attached substrates to form a frame-shaped seal pattern. Next, while the sealant is still uncured, minute droplets of liquid crystal are dropped into the seal frame of the substrate. The other substrate is then superimposed under vacuum, and the sealant is cured by light irradiation or heat to produce a liquid crystal display element. Currently, this dropping method is the mainstream method for manufacturing liquid crystal display elements. Due to such narrow frame designs, the sealant is often applied to an alignment film such as polyimide.

[0004] Japanese Patent Application Laid-Open No. 2001-133794 International Publication No. 02 / 092718

[0005] Typically, liquid crystal display elements are manufactured by forming multiple cells collectively on a mother glass and then dividing them into individual cells. In recent years, mother glass and displays have become larger, making substrate peeling more likely to occur during the manufacturing process of liquid crystal display elements. Conventionally, from the viewpoint of adhesiveness and moisture resistance, (meth)acrylic compounds and the like have been used as curable resins incorporated into sealants, which are then photocured. However, peeling of the substrates has sometimes occurred, particularly due to vibrations during transportation after the photocuring process. The present invention aims to provide a sealant for liquid crystal display elements that has excellent adhesiveness and moisture resistance to alignment films and can suppress peeling after photocuring even when applied to large substrates.

[0006] Disclosure 1 provides a sealant for a liquid crystal display element, which contains a curable resin and a photopolymerization initiator, wherein the curable resin contains a compound represented by the following formula (1), and the sealant is capable of irradiating ultraviolet light having a wavelength of 365 nm at a rate of 3000 mJ / cm ２ The cured product of the sealant for liquid crystal display elements obtained by irradiating the sealant has a thickness of 5.0 μm, and the compressive shear adhesive strength to polyimide measured in accordance with JIS K 6852 at 25° C. and a shear rate of 1 mm / sec is 15 kgf / cm ２ The present disclosure 2 is the sealant for liquid crystal display elements of the present disclosure 1, further comprising an organic filler, the content of the organic filler being 5 parts by mass or more relative to 100 parts by mass of the curable resin. The present disclosure 3 is the sealant for liquid crystal display elements of the present disclosure 1, further comprising an organic filler in an amount of 5 parts by mass or more relative to 100 parts by mass of the curable resin. The present disclosure 4 is the sealant for liquid crystal display elements of the present disclosure 1, further comprising an organic filler in an amount of 5 parts by mass or more relative to 100 parts by mass of the curable resin. The present disclosure 5 is the sealant for liquid crystal display elements of the present disclosure 1, further comprising an organic filler in an amount of 5 parts by mass or more relative to 100 parts by mass of the curable resin. The present disclosure 6 is the sealant for liquid crystal display elements of the present disclosure 2, further comprising an organic filler in an amount of 5 parts by mass or more relative to 100 parts by mass of the curable resin. The present disclosure 7 is the sealant for liquid crystal display elements of the present disclosure 1, further comprising an organic filler in an amount of 5 parts by mass or more relative to 100 parts by mass of the curable resin. The present disclosure 8 is the sealant for liquid crystal display elements of the present disclosure 1, further comprising an organic filler in an amount of 5 parts by mass or more relative to 100 parts by mass of the curable resin. Ｅ When this is the case, P in the entire curable resin Ｅ The present disclosure 4 is the sealant for liquid crystal display elements according to disclosure 1, 2, or 3, further comprising an inorganic filler, the content of the inorganic filler being 5 parts by mass or more and 30 parts by mass or less relative to 100 parts by mass of the curable resin. The present disclosure 5 is the sealant for liquid crystal display elements according to disclosure 1, 2, or 3, further comprising an inorganic filler, the content of the inorganic filler being 5 parts by mass or more and 30 parts by mass or less relative to 100 parts by mass of the curable resin. The present disclosure 6 is the sealant for liquid crystal display elements according to disclosure 2, 3, or 3, further comprising an inorganic filler, the content of the inorganic filler being 5 parts by mass or more and 30 parts by mass or less relative to 100 parts by mass of the curable resin. The present disclosure 7 is the sealant for liquid crystal display elements according to disclosure 3, 4, or 5, ２After irradiation, the cured product is heated at 120°C for 1 hour to obtain a product with a thickness of 300 µm. The moisture permeability of the product measured in accordance with JIS Z 0208 at 80°C and 90% RH is 75 g / m ２ The sealant for a liquid crystal display element according to Disclosure 1, 2, 3, or 4, wherein the sealant is irradiated with ultraviolet light having a wavelength of 365 nm at a rate of 3000 mJ / cm. ２ The sealant for liquid crystal display elements according to Disclosure 1, 2, 3, 4 or 5, wherein the storage modulus at 25°C of the cured product obtained by irradiation is 3.5 GPa or less.

[0007]

[0008] In formula (1), R １ represents a hydrogen atom or a methyl group, R ２ represents a group represented by the following formula (2-1), (2-2), or (2-3), and R ３ represents a methylene group, a methylmethylene group, a dimethylmethylene group, or a sulfonyl group; X represents an open-ring structure of a lactone; and n is 1 or more and 5 or less.

[0009]

[0010] In formulas (2-1) to (2-3), * represents a bonding position, in formula (2-2), a is an integer of 1 or more and 8 or less, in formula (2-3), b is an integer of 1 or more and 8 or less, c is an integer of 1 or more and 3 or less, and d is an integer of 1 or more and 8 or less. The present invention will be described in detail below.

[0011] The present inventors investigated the use of a partially (meth)acrylic compound having a specific flexible backbone and adjusting the peel adhesion strength of the sealant after photocuring in order to achieve excellent adhesion to alignment films and moisture permeability prevention while suppressing peeling after photocuring. However, adjusting the peel adhesion strength did not result in reproducible results in suppressing peeling after photocuring. Therefore, the present inventors investigated adjusting the low-speed compressive shear adhesive strength of the sealant after photocuring at a shear rate of 1 mm / sec to a specific value or greater. As a result, they found that a sealant for liquid crystal display elements can be obtained that has excellent adhesion to alignment films and moisture permeability prevention, and that can suppress peeling after photocuring even when applied to large substrates, thereby completing the present invention.

[0012] The sealant for liquid crystal display elements of the present invention is irradiated with ultraviolet light having a wavelength of 365 nm at a rate of 3000 mJ / cm ２ The cured product of the sealant for liquid crystal display elements obtained by irradiating the sealant with a thickness of 5.0 μm has a compressive shear adhesive strength to a glass substrate measured in accordance with JIS K 6852 at 25° C. and a shear rate of 1 mm / sec (hereinafter also referred to as “low-speed compressive shear adhesive strength after photocuring”) of 15 kgf / cm ２ The low-speed compressive shear adhesive strength after photocuring is 15 kgf / cm ２ As a result, the sealant for liquid crystal display elements of the present invention can suppress peeling after photocuring. A preferable lower limit of the low-speed compressive shear adhesive strength after photocuring is 20 kgf / cm ２ , and a more preferable lower limit is 25 kgf / cm ２ There is no particular upper limit to the low-speed compressive shear adhesive strength after photocuring, but the substantial upper limit is 100 kgf / cm ２The low-speed compressive shear adhesive strength after photocuring can be measured by the following method. That is, first, two substrates (polyimide substrates) are prepared by applying a polyimide solution to a film thickness of about 100 nm on an ITO substrate having a length of 45 mm, a width of 25 mm, and a thickness of 0.7 mm, and treating the substrate. A sealant is applied to one of the substrates in dots so that the diameter when bonded is 3 mm. The other polyimide substrate is placed on top of the polyimide substrate dotted with the sealant, with a 10 mm shift in the longitudinal direction, with the sealant interposed between them. Thereafter, ultraviolet light of 365 nm wavelength at 3000 mJ / cm is applied using a metal halide lamp or the like. ２ The sealant is cured by irradiation to obtain a test piece having a thickness of 5.0 μm, and the low-speed compressive shear adhesive strength after photocuring can be measured for the obtained test piece at 25° C. and a shear rate of 1 mm / sec in accordance with JIS K 6852.

[0013] The sealant for liquid crystal display elements of the present invention is irradiated with ultraviolet light having a wavelength of 365 nm at a rate of 3000 mJ / cm ２ After irradiation, the cured product is heated at 120°C for 1 hour to obtain a 300 μm thick cured product. The preferred upper limit of the moisture permeability measured in accordance with JIS Z 0208 at 80°C and 90% RH is 75 g / m ２ 24 hours. The moisture permeability is 75 g / m ２ By setting the moisture permeability to 24 hours or less, the reliability of the resulting liquid crystal display device is improved. ２ 24 hours. There is no particular preferred lower limit for the moisture permeability, but the substantial lower limit is 35 g / m ２ ・24 hours.

[0014] The sealant for liquid crystal display elements of the present invention is irradiated with ultraviolet light having a wavelength of 365 nm at a rate of 3000 mJ / cm ２The preferred upper limit of the storage modulus at 25°C of the cured product obtained by irradiating the cured product (hereinafter also referred to as "storage modulus after photocuring") is 3.5 GPa. When the storage modulus after photocuring is 3.5 GPa or less, the sealant for liquid crystal display elements of the present invention is more excellent in the effect of suppressing peeling after photocuring. A more preferred upper limit of the storage modulus after photocuring is 3.0 GPa. Furthermore, from the viewpoint of adhesiveness when adherends are bonded together, a preferred lower limit of the storage modulus after photocuring is 0.1 GPa, and a more preferred lower limit is 1.0 GPa. The storage modulus can be measured using a dynamic viscoelasticity measuring device (for example, "DVA-200" manufactured by IT Measurement Control Co., Ltd.) under conditions of tensile mode, test piece width 5 mm, thickness 0.35 mm, grip width 25 mm, heating rate 10°C / min, and frequency 5 Hz.

[0015] The low-speed compressive shear adhesive strength after photocuring, the moisture permeability, and the storage modulus after photocuring can be set within the above-mentioned ranges by selecting the types and adjusting the content ratios of the curable resin, photopolymerization initiator, and other components such as organic fillers and inorganic fillers, which will be described later.

[0016] The sealant for liquid crystal display elements of the present invention contains a curable resin. The curable resin includes a compound represented by formula (1). By containing the compound represented by formula (1), the sealant for liquid crystal display elements of the present invention has excellent adhesion to alignment films and moisture-proofing properties, and it is easy to achieve the low-speed compressive shear adhesive strength after photocuring and the storage modulus after photocuring within the above-mentioned ranges.

[0017] In the above formula (1), R ２ represents a group represented by the above formula (2-1), (2-2), or (2-3). In particular, from the viewpoint of the adhesiveness of the resulting sealant for liquid crystal display elements and the flexibility of the cured product, the above R ２is preferably a group represented by the above formula (2-2), and more preferably a group in which a in the above formula (2-2) is 2 (ethylene group). In the above formulas (2-1) and (2-3), among the bonding positions indicated by *, the bonding position on the methylene group side is the bonding position with the (meth)acryloyloxy group in the above formula (1). In this specification, the above "(meth)acryloyl" means acryloyl or methacryloyl.

[0018] In the above formula (1), R ３ represents a methylene group, a methylmethylene group, a dimethylmethylene group, or a sulfonyl group. ３ is preferably a methylene group, a methylmethylene group, or a dimethylmethylene group.

[0019] In the above formula (1), X represents a ring-opened lactone structure. Examples of the lactone include γ-undecalactone, ε-caprolactone, γ-decalactone, σ-dodecalactone, γ-nonanolactone, γ-heptanolactone, γ-valerolactone, σ-valerolactone, β-butyrolactone, γ-butyrolactone, β-propiolactone, σ-hexanolactone, and 7-butyl-2-oxepanone. Among these, lactones having a linear main skeleton with 5 to 7 carbon atoms when ring-opened are preferred.

[0020] The compound represented by the formula (1) can be produced by, for example, the following method. ２ and a lactone by heating and stirring in the presence of a polymerization inhibitor, and then adding the phthalic acid or phthalic anhydride and heating and stirring to react. Next, an epoxy compound having a bisphenol skeleton, such as bisphenol A diglycidyl ether, is added to the resulting reaction product and heating and stirring to react some of the epoxy groups in the epoxy compound having a bisphenol skeleton. In this specification, the term "(meth)acrylic" refers to acrylic or methacrylic.

[0021] The curable resin preferably contains another curable resin other than the compound represented by formula (1) for the purposes of adjusting the low-speed compression shear adhesive strength after photocuring, the moisture permeability, and the storage modulus after photocuring, or improving low liquid crystal contamination. When the other curable resin is contained, the content of the compound represented by formula (1) per 100 parts by mass of the curable resin is preferably 10 parts by mass or more, and more preferably 70 parts by mass or more. By ensuring that the content of the compound represented by formula (1) is within this range, it is easier to achieve the low-speed compression shear adhesive strength after photocuring, the moisture permeability, and the storage modulus after photocuring within the above-mentioned ranges. The content of the compound represented by formula (1) is more preferably 15 parts by mass or more, and more preferably 50 parts by mass or more.

[0022] Examples of the other curable resins include epoxy compounds and (meth)acrylic compounds.

[0023] Examples of the epoxy compound include 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, ortho-cresol novolac type epoxy compounds, dicyclopentadiene novolac type epoxy compounds, biphenyl novolac type epoxy compounds, naphthalene phenol novolac type epoxy compounds, glycidylamine type epoxy compounds, alkyl polyol type epoxy compounds, rubber-modified epoxy compounds, and glycidyl ester compounds.

[0024] Commercially available examples of the bisphenol A epoxy compounds include jER828EL and jER1004 (both manufactured by Mitsubishi Chemical Corporation), and EPICLON EXA-850CRP (manufactured by DIC Corporation). Commercially available examples of the bisphenol F epoxy compounds include jER806 and jER4004 (both manufactured by Mitsubishi Chemical Corporation). Commercially available examples of the bisphenol S epoxy compounds include EPICLON EXA1514 (manufactured by DIC Corporation). Commercially available examples of the 2,2'-diallyl bisphenol A epoxy compounds include RE-810NM (manufactured by Nippon Kayaku Co., Ltd.). Commercially available examples of the hydrogenated bisphenol epoxy compounds include EPICLON EXA7015 (manufactured by DIC Corporation). Commercially available examples of the propylene oxide-added bisphenol A epoxy compounds include EP-4000S (manufactured by ADEKA Corporation). Commercially available examples of the resorcinol epoxy compounds include EX-201 (manufactured by Nagase ChemteX Corporation). Commercially available examples of the biphenyl epoxy compounds include jER YX-4000H (manufactured by Mitsubishi Chemical Corporation). Commercially available examples of the sulfide epoxy compounds include YSLV-50TE (manufactured by Nippon Steel Chemical & Material Co., Ltd.). Commercially available examples of the diphenyl ether epoxy compounds include YSLV-80DE (manufactured by Nippon Steel Chemical & Material Co., Ltd.). Commercially available examples of the dicyclopentadiene epoxy compounds include EP-4088S (manufactured by ADEKA Corporation). Commercially available examples of the naphthalene epoxy compounds include EPICLON HP4032 and EPICLON EXA-4700 (both manufactured by DIC Corporation), etc. Commercially available examples of the phenol novolac epoxy compounds include EPICLON N-770 (manufactured by DIC Corporation), etc.Commercially available ortho-cresol novolac epoxy compounds include, for example, EPICLON N-670-EXP-S (manufactured by DIC Corporation). Commercially available dicyclopentadiene novolac epoxy compounds include, for example, EPICLON HP7200 (manufactured by DIC Corporation). Commercially available biphenyl novolac epoxy compounds include, for example, NC-3000P (manufactured by Nippon Kayaku Co., Ltd.). Commercially available naphthalene phenol novolac epoxy compounds include, for example, ESN-165S (manufactured by Nippon Steel Chemical & Material Co., Ltd.). Commercially available glycidylamine epoxy compounds 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.). Commercially available examples of the alkyl polyol epoxy compounds 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). Commercially available examples of the rubber-modified epoxy compounds include YR-450 and YR-207 (both manufactured by Nippon Steel Chemical & Material Co., Ltd.), and Epolead PB (manufactured by Daicel Corporation). Commercially available examples of the glycidyl ester compounds include Denacol EX-147 (manufactured by Nagase ChemteX Corporation). Other commercially available epoxy compounds include, for example, YDC-1312, YSLV-80XY, and YSLV-90CR (all manufactured by Nippon Steel Chemical & Material Co., Ltd.), XAC4151 (manufactured by Asahi Kasei Corporation), jER1031 and jER1032 (both manufactured by Mitsubishi Chemical Corporation), EXA-7120 (manufactured by DIC Corporation), and TEPIC (manufactured by Nissan Chemical Industries, Ltd.).

[0025] The curable resin may also contain, as the other curable resin, a compound having an epoxy group and a (meth)acryloyl group in one molecule other than the compound represented by formula (1). Examples of such compounds include partially (meth)acrylic-modified epoxy compounds obtained by reacting a portion of the epoxy groups in an epoxy compound having two or more epoxy groups in one molecule with (meth)acrylic acid.

[0026] 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)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.

[0027] 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.

[0028] 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, and propylene glycol di(meth)acrylate. Examples of suitable 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.

[0029] 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.

[0030] 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. Epoxy compounds that serve as raw materials for the epoxy (meth)acrylate include the epoxy compounds listed above as other curable resins.

[0031] 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 EBECRYL 860, EBECRYL 3200, EBECRYL 3201, EBECRYL 3412, EBECRYL 3600, EBECRYL 3700, EBECRYL 3701, EBECRYL 3702, EBECRYL 3703, EBECRYL 3708, EBECRYL 3800, EBECRYL 6040, and EBECRYL RDX 63182. 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, Epoxy Ester 400EA, etc. Examples of the epoxy (meth)acrylates manufactured by Nagase ChemteX Corporation include Denacol Acrylate DA-141, Denacol Acrylate DA-314, Denacol Acrylate DA-911, etc.

[0032] The urethane (meth)acrylate can be obtained, for example, by reacting a polyfunctional isocyanate compound with a (meth)acrylic acid derivative having a hydroxyl group in the presence of a catalytic amount of a tin compound.

[0033] Examples of the polyfunctional isocyanate compound 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.

[0034] Furthermore, the polyfunctional isocyanate compound may be a chain-extended polyfunctional isocyanate compound obtained by reacting a polyol with an excess of the polyfunctional isocyanate compound. Examples of the polyol include ethylene glycol, propylene glycol, glycerin, sorbitol, trimethylolpropane, carbonate diol, polyether diol, polyester diol, and polycaprolactone diol.

[0035] Examples of the (meth)acrylic acid derivatives 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)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Examples of the dihydric alcohols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and polyethylene glycol. Examples of the trihydric alcohols include trimethylolethane, trimethylolpropane, and glycerin. Examples of the epoxy (meth)acrylates include bisphenol A-type epoxy acrylate.

[0036] Among the above 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 Industrial 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 above urethane (meth)acrylate 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 Co., Ltd. include EBECRYL210, EBECRYL220, EBECRYL230, EBECRYL270, EBECRYL1290, EBECRYL2220, EBECRYL4827, EBECRYL4842, EBECRYL4858, EBECRYL5129, EBECRYL6700, EBECRYL8402, EBECRYL8803, EBECRYL8804, EBECRYL8807, and EBECRYL9260. Examples of the 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.

[0037] The ratio of the number of epoxy groups in one molecule of the compound contained in the curable resin to the total number of epoxy groups and (meth)acryloyl groups in the compound molecule is defined as P Ｅ When this is the case, P in the entire curable resin Ｅ The preferred lower limit of the epoxy functional group ratio, expressed as a mass average value of 30%, is 30%. By having the epoxy functional group ratio of 30% or more, it becomes easier to achieve the low-speed compressive shear adhesive strength after photocuring and the storage modulus after photocuring within the above-mentioned ranges. A more preferred lower limit of the epoxy functional group ratio is 35%. Furthermore, from the viewpoint of low liquid crystal contamination, etc., the preferred upper limit of the epoxy functional group ratio is 50%, and more preferably 45%.

[0038] The sealing agent for liquid crystal display elements of the present invention contains a photopolymerization initiator. Examples of the photopolymerization 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, and 2-methyl-1-(4-methylthiophenyl)- ... -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, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4-dimethylthioxanthen-9-one, and the like.

[0039] 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. By using a photopolymerization initiator in this range, the resulting sealant for liquid crystal display elements has better storage stability and photocurability. The more preferred lower limit of the content of the photopolymerization initiator is 0.1 parts by mass, and the more preferred upper limit is 5 parts by mass.

[0040] The sealant for liquid crystal display elements of the present invention may contain a thermal polymerization initiator. Examples of the thermal polymerization initiator include those composed of an azo compound, an organic peroxide, etc. Among these, a polymeric azo initiator composed of a polymeric azo compound is preferred. The thermal polymerization initiator may be used alone or in combination of two or more. In this specification, the term "polymeric azo compound" refers to a compound having an azo group, generating radicals by heat, and having a number average molecular weight of 300 or more.

[0041] The number-average molecular weight of the polymeric azo compound is preferably 1,000 at its lower limit and 300,000 at its upper limit. By ensuring that the number-average molecular weight of the polymeric azo compound is within this range, the polymeric azo compound can be easily mixed with a curable resin while suppressing liquid crystal contamination. The number-average molecular weight of the polymeric azo compound is more preferably 5,000 at its lower limit and 100,000 at its upper limit, and even more preferably 10,000 at its lower limit and 90,000 at its upper limit.

[0042] Examples of the polymeric azo compounds include those having a structure in which multiple units such as polyalkylene oxide or polydimethylsiloxane are bonded via an azo group. As the polymeric azo compounds having a structure in which multiple units such as polyalkylene oxide are bonded via an azo group, those having a polyethylene oxide structure are preferred. Specific examples of the polymeric azo compounds include polycondensates of 4,4'-azobis(4-cyanopentanoic acid) and polyalkylene glycol, and polycondensates of 4,4'-azobis(4-cyanopentanoic acid) and polydimethylsiloxane having a terminal amino group. Commercially available examples of the polymeric azo compounds include VPE-0201, VPE-0401, VPE-0601, VPS-0501, and VPS-1001 (all manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). Examples of non-polymeric azo compounds include V-65 and V-501 (both manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.).

[0043] Examples of the organic peroxide include ketone peroxides, peroxyketals, hydroperoxides, dialkyl peroxides, peroxyesters, diacyl peroxides, and peroxydicarbonates.

[0044] 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. When the content of the thermal polymerization initiator is 0.05 parts by mass or more, the sealant for liquid crystal display elements of the present invention has superior thermosetting properties. When the content of the thermal polymerization initiator is 10 parts by mass or less, the sealant for liquid crystal display elements of the present invention has superior low liquid crystal contamination properties and storage stability. The lower limit of the content of the thermal polymerization initiator is more preferably 0.1 parts by mass, and the upper limit is more preferably 5 parts by mass.

[0045] The sealant for liquid crystal display elements of the present invention preferably contains a heat curing agent. Examples of the heat curing agent include organic acid hydrazides, imidazole derivatives, amine compounds, polyhydric phenol compounds, and acid anhydrides. Among these, organic acid hydrazides are preferably used.

[0046] Examples of the organic acid hydrazides include sebacic acid dihydrazide, isophthalic acid dihydrazide, adipic acid dihydrazide, and malonic acid dihydrazide. Commercially available organic acid hydrazides include those manufactured by Otsuka Chemical Co., Ltd., those manufactured by Ajinomoto Fine-Techno Co., Ltd., and those manufactured by Japan FineChem Co., Ltd. Examples of the organic acid hydrazides manufactured by Otsuka Chemical Co., Ltd. include SDH and ADH. Examples of the organic acid hydrazides manufactured by Ajinomoto Fine-Techno Co., Ltd. include Amicure VDH, Amicure VDH-J, Amicure UDH, and Amicure UDH-J. Examples of the organic acid hydrazides manufactured by Japan FineChem Co., Ltd. include MDH.

[0047] The content of the thermosetting 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. By using the thermosetting agent in this range, the resulting sealant for liquid crystal display elements can have excellent thermosetting properties while maintaining storage stability and coatability. The more preferred upper limit of the content of the thermosetting agent is 30 parts by mass.

[0048] The sealant for liquid crystal display elements of the present invention preferably contains an organic filler, which makes it easier to set the low-speed compressive shear adhesive strength after photocuring and the storage modulus after photocuring within the above-mentioned ranges.

[0049] Examples of the organic filler include polyester fine particles, polyurethane fine particles, vinyl polymer fine particles, and (meth)acrylic polymer fine particles. The organic filler may have a core-shell structure. Among these, (meth)acrylic polymer fine particles having a core-shell structure are preferred.

[0050] The preferred lower limit of the average particle size of the organic filler is 0.1 μm, and the preferred upper limit is 0.8 μm. By having the average particle size of the organic filler in this range, it becomes easier to set the low-speed compressive shear adhesive strength after photocuring and the storage modulus after photocuring within the above-mentioned ranges. A more preferred upper limit of the average particle size of the organic filler is 0.5 μm. The average particle size of the organic filler can be measured, for example, by dispersing the organic filler in a solvent (water, organic solvent, etc.) using a particle size distribution analyzer. Examples of the particle size distribution analyzer include a NICOMP 380ZLS (manufactured by PARTICLE SIZING SYSTEMS).

[0051] The preferred lower limit of the content of the organic filler is 5 parts by mass relative to 100 parts by mass of the curable resin. By having the content of the organic filler be 5 parts by mass or more, it becomes easier to set the low-speed compressive shear adhesive strength after photocuring and the storage modulus after photocuring within the above-mentioned ranges. A more preferred lower limit of the content of the organic filler is 10 parts by mass. Furthermore, from the viewpoint of coatability, etc., a preferred upper limit of the content of the organic filler is 40 parts by mass, and a more preferred upper limit is 30 parts by mass.

[0052] The sealant for liquid crystal display elements of the present invention preferably contains the inorganic filler for the purposes of improving moisture permeability prevention, increasing viscosity, improving adhesion due to a stress dispersion effect, improving the linear expansion coefficient, etc. However, if the inorganic filler is contained in a large amount, it becomes difficult to set the low-speed compressive shear adhesive strength after photocuring and the storage modulus after photocuring within the above-mentioned ranges.

[0053] 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.

[0054] The content of the inorganic filler is preferably 5 parts by mass or more inclusive, and 30 parts by mass or more inclusive, relative to 100 parts by mass of the curable resin. When the content of the inorganic filler is 5 parts by mass or more, the effect of improving moisture permeability prevention and the like is more excellent. When the content of the inorganic filler is 30 parts by mass or less, it is easier to set the low-speed compression shear adhesive strength and storage modulus after photocuring within the above-mentioned ranges. A more preferred lower limit of the content of the inorganic filler is 10 parts by mass, and a more preferred upper limit is 25 parts by mass.

[0055] 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, etc. Suitable examples of the silane coupling agent include 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-glycidoxypropyltrimethoxysilane.

[0056] 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. By having the content of the silane coupling agent in this range, the effect of improving adhesion while suppressing the occurrence of liquid crystal contamination is more excellent. 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 sealant for a liquid crystal display element of the present invention may contain a light-shielding agent. By containing the light-shielding agent, the sealant for a liquid crystal display element of the present invention can be suitably used as a light-shielding sealant.

[0058] Examples of the light-shielding agent include iron oxide, titanium black, aniline black, cyanine black, fullerene, carbon black, resin-coated carbon black, etc. Among these, titanium black is preferred.

[0059] The titanium black is a substance that exhibits a higher transmittance for light near the ultraviolet region, particularly light with wavelengths of 370 nm to 450 nm, compared to the average transmittance for light with wavelengths of 300 nm to 800 nm. In other words, the titanium black is a light-blocking agent that imparts light-blocking properties to the sealant for liquid crystal display elements of the present invention by sufficiently blocking light with wavelengths in the visible light region, while allowing light with wavelengths near the ultraviolet region to pass through. Therefore, by using a photopolymerization initiator capable of initiating a reaction with light of a wavelength (370 nm to 450 nm) at which the transmittance of the titanium black is high, the photocurability of the sealant for liquid crystal display elements of the present invention can be further improved. Furthermore, the light-blocking agent contained in the sealant for liquid crystal display elements of the present invention is preferably a substance with high insulating properties, and titanium black is also suitable as a highly insulating light-blocking agent. The titanium black preferably has an optical density (OD value) per μm of 3 or more, more preferably 4 or more. The higher the light-shielding ability of the titanium black, the better. There is no particular upper limit to the OD value of the titanium black, but it is usually 5 or less.

[0060] Although the titanium black exhibits sufficient effects even when not surface-treated, surface-treated titanium black can also be used, such as titanium black whose surface is treated with an organic component such as a coupling agent, or titanium black coated with an inorganic component such as silicon oxide, titanium oxide, germanium oxide, aluminum oxide, zirconium oxide, or magnesium oxide. Among these, titanium black treated with an organic component is preferred because it can further improve insulation. Furthermore, a liquid crystal display element manufactured using the sealant for liquid crystal display elements of the present invention, which contains the titanium black as a light-blocking agent, has sufficient light-blocking properties, resulting in a liquid crystal display element with no light leakage, high contrast, and excellent image display quality.

[0061] Commercially available titanium blacks include titanium black manufactured by Mitsubishi Materials Corporation and titanium black manufactured by Ako Kasei Co., Ltd. Examples of titanium blacks manufactured by Mitsubishi Materials Corporation include 12S, 13M, 13M-C, 13R-N, and 14M-C. Examples of titanium blacks manufactured by Ako Kasei Co., Ltd. include Tilac D.

[0062] The preferred lower limit of the specific surface area of ​​the titanium black is 13 m ２ / g, the preferred upper limit is 30m ２ / g, and a more preferable lower limit is 15m ２ / g, and a more preferable upper limit is 25m ２ The volume resistivity of the titanium black preferably has a lower limit of 0.5 Ω·cm and an upper limit of 3 Ω·cm, more preferably a lower limit of 1 Ω·cm and an upper limit of 2.5 Ω·cm.

[0063] The primary particle diameter of the light-shielding agent is not particularly limited as long as it is equal to or less than the distance between the substrates of the liquid crystal display element, but a preferred lower limit is 1 nm and a preferred upper limit is 5000 nm. By having the primary particle diameter of the light-shielding agent within this range, the resulting sealant for liquid crystal display elements can have excellent light-shielding properties without deteriorating its coatability, etc. The primary particle diameter of the light-shielding agent is more preferably 5 nm lower limit, more preferably 200 nm upper limit, even more preferably 10 nm lower limit, and even more preferably 100 nm upper limit. The primary particle diameter of the light-shielding agent can be measured by dispersing the light-shielding agent in a solvent (water, organic solvent, etc.) using a NICOMP 380ZLS (manufactured by PARTICLE SIZING SYSTEMS).

[0064] The preferred lower limit of the content of the light-blocking agent in 100 parts by mass of the sealant for liquid crystal display elements of the present invention is 5 parts by mass, and the preferred upper limit is 80 parts by mass. By having the content of the light-blocking agent within this range, the adhesiveness, post-curing strength, and drawability of the resulting sealant for liquid crystal display elements can be improved without decreasing, and the effect of improving the light-blocking properties can be further achieved. The more preferred lower limit of the content of the light-blocking agent is 10 parts by mass, the more preferred upper limit is 70 parts by mass, the even more preferred lower limit is 30 parts by mass, and the even more preferred upper limit is 60 parts by mass.

[0065] The sealant for a liquid crystal display element of the present invention may further contain additives such as a stress relaxation agent, a reactive diluent, a curing accelerator, an antifoaming agent, a leveling agent, and a polymerization inhibitor, if necessary.

[0066] The method for producing the sealant for liquid crystal display elements of the present invention includes, for example, a method of mixing a curable resin, a photopolymerization initiator, and other components such as an organic filler or an inorganic filler using a mixer. Examples of the mixer include a homodisper, a homomixer, a universal mixer, a planetary mixer, a kneader, and a three-roll mill.

[0067] Furthermore, by blending conductive fine particles into the sealant for liquid crystal display elements of the present invention, a vertical conductive material can be produced. Examples of the conductive fine particles that can be used include metal balls and resin fine particles with a conductive metal layer formed on their surfaces. Among these, resin fine particles with a conductive metal layer formed on their surfaces are preferred because the excellent elasticity of the resin fine particles allows for conductive connection without damaging transparent substrates, etc.

[0068] A liquid crystal dropping method is preferably used as a method for producing a liquid crystal display element using the sealant for liquid crystal display elements of the present invention, and specific examples include methods having the following steps. First, a step 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 the alignment film of one of two transparent substrates having an electrode such as an ITO thin film and an alignment film, thereby forming a frame-shaped seal pattern. Next, a step is performed in which minute droplets of liquid crystal are dropwise applied to the entire frame of the seal pattern, and the other transparent substrate is superimposed under vacuum. Thereafter, a liquid crystal display element can be obtained by a step of irradiating the seal pattern portion with light such as ultraviolet light to temporarily cure the sealant (photocuring step), and a step of heating the temporarily cured sealant to permanently cure it (thermal curing step).

[0069] According to the present invention, it is possible to provide a sealant for liquid crystal display elements that has excellent adhesion to alignment films and moisture-proofing properties, and that can suppress peeling after photocuring even when applied to large substrates.

[0070] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0071] (Preparation of Curable Resin A) 116 parts by mass of 2-hydroxyethyl acrylate, 114 parts by mass of ε-caprolactone, and 0.5 parts by mass of hydroquinone as a polymerization inhibitor were added to a reaction flask, and the mixture was stirred at 90°C for 5 hours using a mantle heater. Thereafter, 148 parts by mass of phthalic anhydride was added, and the mixture was stirred for an additional 5 hours. Next, 340 parts by mass of bisphenol A diglycidyl ether was added to the resulting reaction product, and then 0.5 parts by mass of triphenylphosphine was added, and the mixture was stirred at 110°C for 5 hours, thereby obtaining Curable Resin A. １ H-NMR and １３ It was confirmed by C-NMR that the curable resin A contains 50% by mass of a compound represented by the following formula (3), 25% by mass of a compound represented by the following formula (4), and 25% by mass of bisphenol A diglycidyl ether (P of the curable resin A). Ｅ can be considered as 0.5).

[0072]

[0073]

[0074] (Preparation of Curable Resin B) Curable resin B was obtained in the same manner as in the above "(Preparation of Curable Resin A)" except that the blending amount of ε-caprolactone was 228 parts by mass. １ H-NMR and １３ It was confirmed by C-NMR that the curable resin B contains 50% by mass of a compound represented by the following formula (5), 25% by mass of a compound represented by the following formula (6), and 25% by mass of bisphenol A diglycidyl ether (P of the curable resin B). Ｅ can be considered as 0.5).

[0075]

[0076]

[0077] (Preparation of Curable Resin C) Curable resin C was obtained in the same manner as in "(Preparation of Curable Resin A)" above, except that the blending amount of bisphenol A diglycidyl ether was 170 parts by mass. １ H-NMR and １３ It was confirmed by C-NMR that the curable resin C was the compound represented by the above formula (4).

[0078] (Preparation of curable resin D) Curable resin D was obtained in the same manner as in "(Preparation of curable resin A)" above, except that the blending amount of ε-caprolactone was 228 parts by mass and the blending amount of bisphenol A diglycidyl ether was 170 parts by mass. １ H-NMR and １３ It was confirmed by C-NMR that the curable resin D was the compound represented by the above formula (6).

[0079] (Examples 1 to 13, Comparative Examples 1 to 9) According to the compounding ratios shown in Tables 1 and 2, each material was stirred with a planetary stirrer and then uniformly mixed with a ceramic triple roll to obtain sealants for liquid crystal display elements of Examples 1 to 13 and Comparative Examples 1 to 9. Awatori Rentaro (manufactured by Thinky Corporation) was used as the planetary stirrer. The epoxy functional group ratio of the curable resin in each of the obtained sealants for liquid crystal display elements is shown in Tables 1 and 2.

[0080] (Low-Speed ​​Compression Shear Adhesion Strength After Photocuring) The obtained sealant for liquid crystal display elements was applied in dots to one of two polyimide substrates measuring 45 mm in length, 25 mm in width, and 0.7 mm in thickness, so that the diameter of the adhesive bonded would be 3 mm. The other polyimide substrate was placed on top of the dotted polyimide substrate with the sealant interposed therebetween, with a longitudinal offset of 10 mm. Subsequently, a metal halide lamp was used to apply light at a wavelength of 365 nm and an illuminance of 100 mW / cm. ２ of ultraviolet light for 30 seconds (accumulated light intensity 3000 mJ / cm ２ ) to obtain test pieces having a cured sealant with a thickness of 5.0 μm. The metal halide lamp used was an SE-1500M (manufactured by Sen Special Light Sources Co., Ltd.), and ultraviolet light was irradiated through a 340 nm cut filter (manufactured by Asahi Spectroscopic Co., Ltd.). The compressive shear adhesive strength (low-speed compressive shear adhesive strength) of the obtained test pieces was measured using an Autograph AGX (manufactured by Shimadzu Corporation) in accordance with JIS K 6852 at 25°C and a shear rate of 1 mm / sec. The results are shown in Tables 1 and 2.

[0081] (Storage Modulus After Photocuring) Each of the obtained sealants for liquid crystal display elements was subjected to photocuring using a metal halide lamp at a wavelength of 365 nm and an illuminance of 100 mW / cm. ２ of ultraviolet light for 30 seconds (accumulated light intensity 3000 mJ / cm ２ ) to obtain a cured product. The metal halide lamp used was an SE-1500M (manufactured by Sen Special Light Sources Co., Ltd.), and ultraviolet light was irradiated through a 340 nm cut filter (manufactured by Asahi Spectroscopy). The obtained cured product was subjected to dynamic viscoelasticity measurement using a dynamic viscoelasticity measuring device under the conditions of tensile mode, test piece width 5 mm, thickness 0.35 mm, grip width 25 mm, heating rate 10°C / min, and frequency 5 Hz, and the storage modulus at 25°C was measured. The results are shown in Tables 1 and 2.

[0082] <Evaluation> The sealants for liquid crystal display elements obtained in the examples and comparative examples were evaluated as follows. The results are shown in Tables 1 and 2.

[0083] (Adhesion to Alignment Film) An imide resin was spin-coated onto a glass substrate with an ITO thin film, prebaked at 80°C, and then baked at 230°C to prepare a substrate with an alignment film. SE7492 (manufactured by Nissan Chemical Industries, Ltd.) was used as the imide resin. The resulting alignment film (imide alignment film) had a thickness of 100 nm. One part by mass of silica spacers was uniformly dispersed in 100 parts by mass of each sealant for liquid crystal display elements obtained in the Examples and Comparative Examples using a planetary stirrer. SI-H055 (manufactured by Sekisui Chemical Co., Ltd.) was used as the silica spacer. Next, the sealant with dispersed silica spacers was dispensed in small drops onto the alignment film of the substrate with an alignment film. Another substrate with an alignment film was then bonded in a cross shape to the substrate with the sealant dispensed thereon, with the sealant interposed between them, and the substrate was heated with a metal halide lamp at a wavelength of 365 nm and an illuminance of 100 mW / cm. ２ of ultraviolet light for 30 seconds (accumulated light intensity 3000 mJ / cm ２ ) and then heated at 120°C for 1 hour to obtain an adhesive test piece. A metal halide lamp, SE-1500M (manufactured by Sen Special Light Sources Co., Ltd.), was used, and ultraviolet light was irradiated through a 340 nm cut filter (manufactured by Asahi Spectroscopy). The edge of the substrate of the prepared adhesive test piece was pressed at a rate of 5 mm / min using a metal cylinder with a radius of 5 mm, and the strength at which panel peeling occurred was measured. The obtained measured value (kgf) divided by the seal diameter (cm) was evaluated as follows: 3.0 kgf / cm or more was marked with "◎", 2.5 kgf / cm or more but less than 3.0 kgf / cm was marked with "○", 2.0 kgf / cm or more but less than 2.5 kgf / cm was marked with "△", and less than 2.0 kgf / cm was marked with "×". Adhesion to the alignment film was evaluated as follows:

[0084] (Moisture Permeability) Each of the sealants for liquid crystal display elements obtained in the Examples and Comparative Examples was applied onto a smooth release film using a coater. Then, the sealant was irradiated with a metal halide lamp at a wavelength of 365 nm and an illuminance of 100 mW / cm. ２ of ultraviolet light for 30 seconds (accumulated light intensity 3000 mJ / cm ２) and then heated at 120°C for 1 hour to obtain a 300 μm thick film for moisture permeability measurement. An SE-1500M (manufactured by Sen Special Light Sources Co., Ltd.) was used as the metal halide lamp, and ultraviolet light was irradiated through a 340 nm cut filter (manufactured by Asahi Spectroscopy Co., Ltd.). A moisture permeability test cup was prepared according to the method for testing moisture permeability of moisture-proof packaging materials (cup method) of JIS Z 0208, and the obtained moisture permeability measurement film was attached to it. The cup was then placed in a constant temperature and humidity oven at a temperature of 80°C and a humidity of 90% RH to measure the moisture permeability.

[0085] (Peeling Resistance After Photocuring) 1 part by mass of silica spacer was added to 100 parts by mass of each liquid crystal display element sealant obtained in the Examples and Comparative Examples, and the mixture was uniformly dispersed using a planetary stirrer. The mixture was then degassed to remove any bubbles in the liquid crystal display element sealant, and then filled into a dispensing syringe and degassed again. SI-H055 (manufactured by Sekisui Chemical Co., Ltd.) was used as the silica spacer, and PSY-10E (manufactured by Musashi Engineering Co., Ltd.) was used as the dispensing syringe. Next, the liquid crystal display element sealant was applied to a glass substrate in a framed pattern using a dispenser. A SHOTMASTER 300 (manufactured by Musashi Engineering Co., Ltd.) was used as the dispenser. Next, minute droplets of FFS liquid crystal were dropwise applied within the frame of the liquid crystal display element sealant using a liquid crystal dropping device. A glass substrate was placed on top of the glass substrate on which the FFS liquid crystal had been dropwise coated, with another glass substrate sandwiched between them via a sealant for liquid crystal display elements. The two substrates were then bonded together under a reduced pressure of 5 Pa using a vacuum bonding device to obtain a cell. JC-5223XX (manufactured by Chisso Corporation) was used as the FFS liquid crystal. The resulting cell was illuminated with a metal halide lamp at a wavelength of 365 nm and an illuminance of 100 mW / cm. ２ of ultraviolet light for 30 seconds (accumulated light intensity 3000 mJ / cm ２) to produce a liquid crystal display element in which the sealant for liquid crystal display elements was cured using only light. An SE-1500M (manufactured by Sen Special Light Sources Co., Ltd.) was used as the metal halide lamp, and ultraviolet light was irradiated through a 340 nm cut filter (manufactured by Asahi Spectroscopic Co., Ltd.). The obtained liquid crystal display element was exposed to an ultrasonic cleaner (manufactured by AS ONE Corporation, "VS-10003", 28 kH conditions) for 10 minutes. After exposure, the liquid crystal display element was observed under a microscope, and peeling resistance after photocuring was evaluated by assigning "○" if no peeling of the substrate was observed and "×" if peeling of the substrate was observed.

[0086]

[0087]

[0088] According to the present invention, it is possible to provide a sealant for liquid crystal display elements that has excellent adhesion to alignment films and moisture-proofing properties, and that can suppress peeling after photocuring even when applied to large substrates.

Claims

1. A sealant for a liquid crystal display element, comprising a curable resin and a photopolymerization initiator, The curable resin contains a compound represented by the following formula (1): 3000mJ / cm of ultraviolet light with a wavelength of 365nm ２ The cured product of the sealant for liquid crystal display elements obtained by irradiating the liquid crystal display element has a thickness of 5.0 μm, and the compressive shear adhesive strength to polyimide measured at 25° C. and a shear rate of 1 mm / sec according to JIS K 6852 is 15 kgf / cm ２ That's all. A sealant for a liquid crystal display device. 【Chemistry 1】 In formula (1), R １ represents a hydrogen atom or a methyl group, R ２ represents a group represented by the following formula (2-1), (2-2), or (2-3), and R ３ represents a methylene group, a methylmethylene group, a dimethylmethylene group, or a sulfonyl group; X represents a lactone ring-open structure; and n is 1 or more and 5 or less. 【Chemistry 2】 In formulas (2-1) to (2-3), * represents a bonding position; in formula (2-2), a is an integer of 1 or more and 8 or less; in formula (2-3), b is an integer of 1 or more and 8 or less; c is an integer of 1 or more and 3 or less; and d is an integer of 1 or more and 8 or less.

2. Further, it contains an organic filler, 2. The sealant for liquid crystal display elements according to claim 1, wherein the content of said organic filler is 5 parts by mass or more based on 100 parts by mass of said curable resin.

3. The ratio of the number of epoxy groups in one molecule of the compound contained in the curable resin to the total number of epoxy groups and (meth)acryloyl groups in the compound molecule is P Ｅ When the above formula is used, P in the entire curable resin is Ｅ 3. The sealant for liquid crystal display elements according to claim 1, wherein the epoxy functional group ratio, expressed as a mass average value, is 30% or more.

4. Further, it contains an inorganic filler, 3. The sealant for liquid crystal display elements according to claim 1, wherein the content of the inorganic filler is 5 parts by mass or more and 30 parts by mass or less based on 100 parts by mass of the curable resin.

5. 3000mJ / cm of ultraviolet light with a wavelength of 365nm ２ After irradiation, the composition is heated at 120°C for 1 hour to obtain a cured product having a thickness of 300 µm. The moisture permeability of the cured product in an environment of 80°C and 90% RH, as measured according to JIS Z 0208, is 75 g / m ２ The sealant for liquid crystal display elements according to claim 1 or 2, wherein the shelf life is 24 hours or less.

6. 3000mJ / cm of ultraviolet light with a wavelength of 365nm ２ 3. The sealant for liquid crystal display elements according to claim 1, wherein the storage modulus at 25° C. of the cured product obtained by irradiation is 3.5 GPa or less.

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