Sealant for optical device

Abstract

To provide a sealant for an optical device excellent in both adhesiveness and moisture-proof property.SOLUTION: There is provided the sealant for an optical device including: a curable resin; at least one type selected from the group consisting of a polymerization initiator and a thermosetting agent; and a terpene resin.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a sealant for optical devices. [Background technology]

[0002] In recent years, liquid crystal display elements and organic EL 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 and electrochromic elements using electrochromic compounds are widely used as light control elements whose light transmittance changes when a voltage is applied. In optical devices such as these display elements and light control elements, sealants are usually used for bonding various components and sealing liquid materials.

[0003] For example, a liquid crystal dropping method using a sealant, as disclosed in Patent Documents 1 and 2, is used as a manufacturing method for liquid crystal display elements from the viewpoint 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, and the other substrate is then superimposed under vacuum, and the sealant is cured to produce a liquid crystal display element. This dropping method is currently the mainstream method for manufacturing liquid crystal display elements.

[0004] Liquid crystal light control devices are light control devices that control the amount of light transmission by changing the orientation of liquid crystal molecules by changing the potential difference between transparent electrode layers, and have excellent responsiveness. Electrochromic devices are light control devices that reversibly change color through the electrochemical oxidation-reduction reaction of electrochromic compounds. Because they can maintain their colored state until they are decolorized, they can be driven with low power consumption. In such light control devices, a sealant is used to seal the liquid crystal, electrochromic compound solution, etc., as disclosed in Patent Documents 3 and 4. [Prior art documents] [Patent documents]

[0005] [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 [Patent Document 4] Patent No. 7327621 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, optical devices such as display elements and light-adjusting elements have increasingly been required to have moisture-resistant reliability when operated in high-temperature, high-humidity environments. This has led to increased demands for sealants to be able to prevent water from penetrating from the outside. To improve the moisture-resistant reliability of optical devices, it is necessary to improve the adhesion of the sealant to the substrate, etc., to prevent water penetration from the interface between the sealant and the substrate, and also to improve the moisture-proofing properties of the sealant. While blending fillers such as talc into sealants has been considered as a method for improving the moisture-proofing properties of sealants, rigorous moisture-proofing tests have sometimes resulted in problems (unevenness) in the display and light-adjusting performance of optical devices. In particular, the application width of sealants in optical devices has tended to become narrower in recent years, making it difficult to achieve both adhesion and moisture-proofing properties even with sealants that previously presented no problems.

[0007] An object of the present invention is to provide a sealant for optical devices that is excellent in both adhesiveness and moisture permeation prevention properties. [Means for solving the problem]

[0008] Disclosure 1 relates to a sealant for optical devices, which contains a curable resin, at least one selected from the group consisting of a polymerization initiator and a heat curing agent, and a terpene resin. Disclosure 2 relates to the sealant for an optical device according to Disclosure 1, wherein the terpene resin is a copolymer of two or more types of terpenes. The present disclosure 3 is the sealant for an optical device according to the present disclosure 1 or 2, wherein the terpene resin is a compound having a structure represented by the following formula (1-1) and the following formula (1-2). The present disclosure 4 is the sealant for an optical device according to the present disclosure 1, 2, or 3, wherein the terpene resin has a softening point of 75°C or higher and 90°C or lower. The present disclosure 5 is the sealant for an optical device according to the present disclosure 1, 2, 3 or 4, wherein the content of the terpene resin relative to 100 parts by mass of the curable resin is 0.5 parts by mass or more and 20 parts by mass or less. The present disclosure 6 is the sealant for an optical device according to the present disclosure 1, 2, 3, 4 or 5, wherein the curable resin contains a compound having two or more (meth)acryloyl groups in one molecule. The present disclosure 7 is a sealant for optical devices according to the present disclosure 6, in which the content of the terpene resin relative to 100 parts by mass of the compound having two or more (meth)acryloyl groups in one molecule is 0.5 parts by mass or more and 25 parts by mass or less. The present disclosure 8 is the sealant for an optical device according to the present disclosure 1, 2, 3, 4, 5, 6, or 7, wherein the curable resin contains an epoxy compound. The present disclosure 9 is the sealant for an optical device according to the present disclosure 1, 2, 3, 4, 5, 6, 7, or 8, which contains a hydrazide compound or an amine adduct compound as the heat curing agent. Disclosure 10 is a sealant for an optical device according to Disclosure 1, 2, 3, 4, 5, 6, 7, 8, or 9, used in the production of a liquid crystal display element. Disclosure 11 is the sealant for optical devices of Disclosure 10, used in the manufacture of a liquid crystal display element by a liquid crystal dropping method. The present invention will be described in detail below.

[0009] The present inventors have investigated the use of a flexible resin with a long molecular chain as the curable resin for an optical device sealant, thereby imparting flexibility to the sealant and exhibiting stress relaxation properties, thereby ensuring high adhesion. However, the resulting sealant has poor moisture permeability, and the manufactured optical device may have poor moisture resistance reliability. As a result of further intensive research, the present inventors have found that by incorporating a terpene resin into the optical device sealant, an optical device sealant having both excellent adhesion and moisture permeability can be obtained, thereby completing the present invention.

[0010] [ka]

[0011] n in formula (1-1) and m in formula (1-2) each represent the number of repetitions.

[0012] The sealing agent for optical devices of the present invention contains a terpene resin. By containing the terpene resin, the sealing agent for optical devices of the present invention exhibits excellent adhesiveness without deteriorating moisture permeation prevention properties. In this specification, the term "terpene resin" refers collectively to a homopolymer of terpene, a copolymer of two or more types of terpenes, and a copolymer of a terpene and another monomer.

[0013] The terpene resin is preferably a copolymer of two or more terpenes, since the resulting sealant for optical devices will have excellent adhesive properties without deteriorating moisture permeation prevention properties.

[0014] Examples of the terpenes include hemiterpenes, monoterpenes, sesquiterpenes, diterpenes, triterpenes, and derivatives thereof. Among these, monoterpenes are preferred. That is, the terpene resin is preferably a copolymer of two or more monoterpenes.

[0015] Furthermore, the terpene is preferably a cyclic terpene, and more preferably α-pinene, β-pinene, or limonene.

[0016] When the terpene resin is a copolymer of a terpene and another monomer, an aromatic monomer is preferably used as the other monomer. Examples of the aromatic monomer include phenol and styrene.

[0017] Among these, the terpene resin is preferably a compound having a structure represented by the above formula (1-1) and the above formula (1-2).

[0018] The softening point of the terpene resin preferably has an upper limit of 90° C. When the softening point of the terpene resin is 90° C. or lower, the resulting sealant for optical devices has excellent adhesion without deteriorating moisture permeability and has high compatibility with resins. The softening point of the terpene resin more preferably has an upper limit of 85° C. The lower limit of the softening point of the terpene resin is preferably 75° C. When the softening point of the terpene resin is 75° C. or higher, the resulting sealant for optical devices has excellent workability and the like. The softening point of the terpene resin can be measured by a method according to JIS K 2207. When the softening point of the terpene resin is expressed as a range, for example, "a softening point of 90°C or less" means that the upper limit of the range is 90°C or less, and "a softening point of 75°C or more" means that the lower limit of the range is 75°C or more.

[0019] The preferred lower limit of the content of the terpene resin relative to 100 parts by mass of the curable resin described below is 0.5 parts by mass, and the preferred upper limit is 20 parts by mass. When the content of the terpene resin relative to 100 parts by mass of the curable resin is within this range, the resulting sealant for optical devices will have better adhesiveness. The more preferred lower limit of the content of the terpene resin relative to 100 parts by mass of the curable resin is 1 part by mass, the more preferred upper limit is 15 parts by mass, and the even more preferred lower limit is 5 parts by mass. Furthermore, the preferred lower limit of the content of the terpene resin relative to 100 parts by mass of the compound having two or more (meth)acryloyl groups in one molecule (described below) is 0.5 parts by mass, and the preferred upper limit is 25 parts by mass. By having the content of the terpene resin in this range relative to 100 parts by mass of the compound having two or more (meth)acryloyl groups in one molecule, the resulting sealant for optical devices will have better adhesiveness. The more preferred lower limit of the content of the terpene resin relative to 100 parts by mass of the compound having two or more (meth)acryloyl groups in one molecule is 1.2 parts by mass, more preferably 19 parts by mass, and even more preferably 6 parts by mass. In this specification, the term "(meth)acryloyl" means acryloyl or methacryloyl.

[0020] The sealant for optical devices of the present invention contains a curable resin. 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 curable resin preferably contains a compound having two or more (meth)acryloyl groups in one molecule (hereinafter also referred to as a "difunctional or higher (meth)acrylic compound"). In this specification, the term "(meth)acrylic" refers to acrylic or methacrylic, and the term "(meth)acrylic compound" refers to a compound having a (meth)acryloyl group other than the partially (meth)acrylic-modified epoxy compound described below. 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.

[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 epoxy compounds that can be used as raw materials for synthesizing the above-mentioned epoxy (meth)acrylates 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, o-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 type epoxy compounds, and glycidyl ester compounds.

[0023] Commercially available examples of the bisphenol A epoxy compounds include jER828EL and jER1004 (both manufactured by Mitsubishi Chemical Corporation), EPICLON EXA-850CRP (manufactured by DIC Corporation), and the like. Among the above bisphenol F type epoxy compounds, commercially available examples include jER806 and jER4004 (both manufactured by Mitsubishi Chemical Corporation). Among the above bisphenol S type epoxy compounds, commercially available examples include EPICLON EXA1514 (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 EXA7015 (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 HP4032 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 HP7200 (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), 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). 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.).

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] Furthermore, as the polyfunctional isocyanate compound, a chain-extended polyfunctional isocyanate compound obtained by reacting a polyol with an excess amount of the polyfunctional 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.

[0031] 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.

[0032] 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.

[0033] The curable resin preferably contains an epoxy compound for the purpose of further improving the adhesiveness of the resulting sealant for optical devices, etc. Examples of the epoxy compound include the same epoxy compounds as those used as raw materials for synthesizing the above-mentioned epoxy (meth)acrylates, partially (meth)acrylic-modified epoxy compounds, etc. In this specification, the term "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 some of the epoxy groups of an epoxy compound having two or more epoxy groups in one molecule with (meth)acrylic acid.

[0034] When the curable resin contains the (meth)acrylic compound and the epoxy compound, or when the curable resin contains the partially (meth)acrylic-modified epoxy compound, the ratio of (meth)acryloyl groups to the total of (meth)acryloyl groups and epoxy groups in the curable resin is preferably 30 mol % to 95 mol %. When the ratio of (meth)acryloyl groups is within this range, the resulting sealant for optical devices has excellent adhesion while suppressing contamination of liquid crystals, electrochromic compound solutions, etc.

[0035] From the viewpoint of further improving adhesiveness, the curable resin preferably contains a curable resin having a flexible skeleton, more preferably contains a curable resin having a lactone ring-opening structure, further preferably contains a (meth)acrylic compound having a lactone ring-opening structure, and particularly preferably contains a bifunctional or higher functional (meth)acrylic compound having a lactone ring-opening 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, 7-butyl-2-oxepanone, etc. Among these, lactones having a linear main skeleton with 5 to 7 carbon atoms when ring-opened are preferred.

[0036] The preferred lower limit of the content of the curable resin having a flexible skeleton per 100 parts by mass of the curable resin is 20 parts by mass, and the preferred upper limit is 50 parts by mass. When the content of the curable resin having a flexible skeleton is within this range, the resulting sealant for optical devices has excellent adhesion without deteriorating moisture permeation prevention properties. The more preferred lower limit of the content of the curable resin having a flexible skeleton is 25 parts by mass, and the more preferred upper limit is 45 parts by mass.

[0037] The curable resin preferably has a hydrogen-bonding unit such as an -OH group, an -NH- group, or an -NH2 group, from the viewpoint of suppressing contamination of the liquid crystal, the electrochromic compound solution, or the like.

[0038] The preferred lower limit of the total content of the curable resin in 100 parts by mass of the optical device sealant 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 resin is within this range, the resulting optical device sealant has better curability and adhesiveness. The more preferred lower limit of the total content of the curable resin is 60 parts by mass, and the more preferred upper limit is 85 parts by mass.

[0039] The sealing agent for optical devices of the present invention contains at least one selected from the group consisting of a polymerization initiator and a heat curing agent.

[0040] Examples of the polymerization initiator include a photoradical polymerization initiator that generates radicals upon irradiation with light, and a thermal radical polymerization initiator that generates radicals upon heating.

[0041] Examples of the photoradical polymerization initiator include benzophenone-based compounds, acetophenone-based compounds, acylphosphine oxide-based compounds, titanocene-based compounds, oxime ester-based compounds, benzoin ether-based compounds, and thioxanthone-based compounds. Specific examples of the photoradical polymerization 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-2-methyl-1 ... methyl-1-(4-methylthiophenyl)-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), 2,4,6-trimethylbenzoyldiphenylphosphine oxide, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and the like.

[0042] Examples of the thermal radical polymerization initiator include those composed of an azo compound, an organic peroxide, etc. Among them, an initiator composed of an azo compound (hereinafter also referred to as "azo initiator") is preferred from the viewpoint of suppressing contamination of liquid crystal, electrochromic compound solutions, etc.

[0043] Examples of the azo compounds include those having a structure in which a plurality of units such as polyalkylene oxide and polydimethylsiloxane are bonded via azo groups. As the polymeric azo compound having a structure in which a plurality of units such as polyalkylene oxide are bonded via the azo group, those having a polyethylene oxide structure are preferred. Specific examples of the 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.).

[0044] Examples of the organic peroxide include ketone peroxides, peroxyketals, hydroperoxides, dialkyl peroxides, peroxyesters, diacyl peroxides, and peroxydicarbonates.

[0045] The preferred lower limit of the content of the polymerization initiator relative to 100 parts by mass of the curable resin is 0.01 parts by mass, and the preferred upper limit is 10 parts by mass. When the content of the polymerization initiator is 0.01 parts by mass or more, the resulting sealant for optical devices has superior curability. When the content of the polymerization initiator is 10 parts by mass or less, the resulting sealant for optical devices has superior storage stability. The more preferred lower limit of the content of the polymerization initiator is 0.1 parts by mass, and the more preferred upper limit is 5 parts by mass.

[0046] The heat curing agent preferably contains a hydrazide compound or an amine adduct compound, since these compounds have an excellent effect of achieving both heat curing properties and storage stability.

[0047] Examples of the amine adduct compound include adducts obtained by reacting an amine compound such as an imidazole compound or a primary to tertiary amine with an epoxy compound.

[0048] Among the above-mentioned amine adduct compounds, commercially available ones include, for example, amine adduct compounds manufactured by Ajinomoto Fine-Techno Co., Ltd., amine adduct compounds manufactured by Shikoku Chemicals Corporation, amine adduct compounds manufactured by Mitsubishi Chemical Corporation, amine adduct compounds manufactured by ADEKA Corporation, and amine adduct compounds manufactured by T&K TOKA Corporation. Examples of the amine adduct compounds manufactured by Ajinomoto Fine-Techno Co., Inc. include Amicure PN-23, Amicure PN-23J, Amicure PN-H, Amicure PN-31, Amicure PN-31J, Amicure PN-40, Amicure PN-40J, Amicure PN-50, Amicure PN-F, Amicure MY-24, and Amicure MY-H. Examples of the amine adduct compounds manufactured by Shikoku Chemicals Corporation include P-0505. Examples of the amine adduct compounds manufactured by Mitsubishi Chemical Corporation include P-200. Examples of the amine adduct compounds manufactured by ADEKA Corporation include ADEKA Hardener EH-5001P, ADEKA Hardener EH-5057PK, ADEKA Hardener EH-5030S, and ADEKA Hardener EH-5011S. Examples of the amine adduct compounds manufactured by T&K TOKA include Fujicure FXR-1036, Fujicure FXR-1020, and Fujicure FXR-1081.

[0049] Examples of the hydrazide compound include sebacic acid dihydrazide, isophthalic acid dihydrazide, adipic acid dihydrazide, and malonic acid dihydrazide. Among the above hydrazide compounds, commercially available ones include, for example, hydrazide compounds manufactured by Otsuka Chemical Co., Ltd. and hydrazide compounds manufactured by Ajinomoto Fine-Techno Co., Ltd. Examples of the hydrazide compounds manufactured by Otsuka Chemical Co., Ltd. include SDH, ADH, and MDH. Examples of the organic acid hydrazides manufactured by Ajinomoto Fine-Techno Co., Inc. include Amicure VDH, Amicure VDH-J, Amicure UDH, and Amicure UDH-J.

[0050] The preferred lower limit of the content of the thermosetting agent relative to 100 parts by mass of the curable resin is 1 part by mass, and the preferred upper limit is 50 parts by mass. By having the content of the thermosetting agent within this range, the resulting optical device sealant can have excellent thermosetting properties without deteriorating its applicability, etc. The more preferred upper limit of the content of the thermosetting agent is 30 parts by mass.

[0051] The sealing agent for optical devices of the present invention preferably contains a filler for the purposes of adjusting viscosity, further improving adhesion due to stress dispersion effects, improving the linear expansion coefficient, and further improving moisture permeability prevention properties.

[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 50 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 upper limit of the filler content is 40 parts by mass.

[0054] The sealant for optical devices 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 optical devices 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 excellent in improving adhesion to substrates and the like, and can suppress outflow of the curable resin into liquid crystals, electrochromic compound solutions, and the like by chemically bonding with the curable resin.

[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 5 parts by mass. By having the content of the silane coupling agent within this range, contamination of liquid crystal, electrochromic compound solutions, etc. is suppressed, while the adhesiveness is improved. 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 2 parts by mass.

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

[0058] Examples of methods for producing the sealing agent for optical devices of the present invention include a method of mixing a curable resin, at least one selected from the group consisting of a polymerization initiator and a thermosetting agent, a terpene resin, and a silane coupling agent or the like that is added as needed, using a mixer such as a homodisper, a homomixer, a universal mixer, a planetary mixer, a kneader, or a three-roll mill.

[0059] By blending conductive fine particles into the sealing agent for optical devices of the present invention, a vertically conductive material can be produced. The conductive fine particles may be 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 have excellent elasticity and can provide conductive connection without damaging transparent substrates, etc.

[0060] The sealant for optical devices of the present invention is suitably used in the production of liquid crystal display elements, and is more suitably used in the production of liquid crystal display elements by a liquid crystal dropping method. The liquid crystal display element obtained by using the sealant for optical devices of the present invention is preferably a liquid crystal display element with a narrow frame design, specifically, the width of the frame part around the liquid crystal display unit is preferably 2 mm or less. When the above liquid crystal display element is produced, the application width of the sealant for optical devices of the present invention is preferably 1 mm or less.

[0061] Examples of the method for producing a liquid crystal display element by the liquid crystal dropping method using the sealant for optical devices of the present invention include the following method. First, a process is performed in which the optical device sealant 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, while the optical device sealant of the present invention is still in an uncured state, microdroplets of liquid crystal are dropwise applied to the entire frame of the seal pattern, and another substrate is immediately superimposed on the substrate. After that, a liquid crystal display element can be obtained by a process in which the seal pattern portion is irradiated with light such as ultraviolet light to temporarily cure the optical device sealant, and then the temporarily cured sealant is heated to permanently cure it. [Effects of the Invention]

[0062] According to the present invention, it is possible to provide a sealant for optical devices that is excellent in both adhesiveness and moisture permeation prevention properties. DETAILED DESCRIPTION OF THE INVENTION

[0063] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0064] (Examples 1 to 15 and Comparative Examples 1 to 4) The materials were mixed using a planetary mixer according to the compounding ratios shown in Tables 1 and 2, and then further mixed using a three-roll mill to prepare the optical device sealants of Examples 1 to 15 and Comparative Examples 1 to 4. Awatori Rentaro (manufactured by Thinky Corporation) was used as the planetary mixer. In addition, "YS Resin PX800" in the table is a compound having a structure represented by the above formula (1-1) and formula (1-2).

[0065] <Evaluation> The resulting sealant for optical devices was evaluated as follows, and the results are shown in Tables 1 and 2.

[0066] (Adhesiveness) One part by mass of spacer particles was dispersed in 100 parts by mass of the obtained sealant for optical devices, and the resulting mixture was dropped in small drops onto one of two glass substrates (30 x 40 mm) with an ITO thin film. Micropearl SI-H050 (manufactured by Sekisui Chemical Co., Ltd.) was used as the spacer particles. The other glass substrate with an ITO thin film was then attached in a cross shape to this, and a metal halide lamp was used to illuminate the substrate at a wavelength of 365 nm and an illuminance of 100 mW / cm. 2 After irradiating the coated film with ultraviolet light for 30 seconds, the coated film was heated at 120°C for 1 hour to obtain an adhesive test piece. The obtained adhesive test piece was subjected to a tensile test (5 mm / sec) using chucks placed above and below. The obtained measured value (kgf) was used as the sealant application cross-sectional area (cm 2 ) is 3.0kgf / cm 2 If it is above 2.5kgf / cm, it is marked as "◎" 2 Over 3.0kgf / cm 2 If it was less than 2.0kgf / cm, it was marked as "○" 2 More than 2.5kgf / cm 2 If it is less than 2.0kgf / cm, it is marked as "△" 2 If the adhesion was less than 100%, the adhesion was evaluated as "X".

[0067] (Moisture-proof) The obtained sealant for optical devices was applied to a smooth release film using a coater to a thickness of 200 to 300 μm, and then irradiated with a metal halide lamp at a wavelength of 365 nm and an illuminance of 100 mW / cm. 2 After irradiating the film with ultraviolet light for 30 seconds, the film was heated at 120°C for 1 hour to cure the sealant, yielding a film for moisture permeability measurement. A cup for the moisture permeability test was prepared according to the method for testing moisture permeability of moisture-proof packaging materials (cup method) of JIS Z 0208, and the obtained film for moisture permeability measurement was attached to the cup. The cup was then placed in a constant temperature and humidity oven at 80°C and 90% RH to measure the moisture permeability. The obtained moisture permeability value is 100g / m 2 -If it was less than 24 hours, it was marked as "○", and if it was 100g / m 2 If it lasted for 24 hours or more, it was rated as "×" and the moisture permeability was evaluated.

[0068] [Table 1]

[0069] [Table 2] [Industrial Applicability]

[0070] According to the present invention, it is possible to provide a sealant for optical devices that is excellent in both adhesiveness and moisture permeation prevention properties.

Claims

1. A sealant for optical devices, comprising: a curable resin; at least one selected from the group consisting of a polymerization initiator and a heat curing agent; and a terpene resin.

2. 2. The sealant for optical devices according to claim 1, wherein the terpene resin is a copolymer of two or more kinds of terpenes.

3. 3. The sealant for optical devices according to claim 1, wherein the terpene resin is a compound having a structure represented by the following formula (1-1) and the following formula (1-2): 【Chemical 1】 n in formula (1-1) and m in formula (1-2) each represent the number of repetitions.

4. 3. The sealant for optical devices according to claim 1, wherein the terpene resin has a softening point of 75°C or higher and 90°C or lower.

5. 3. The sealant for optical devices according to claim 1, wherein the content of the terpene resin relative to 100 parts by mass of the curable resin is 0.5 parts by mass or more and 20 parts by mass or less.

6. 3. The sealant for optical devices according to claim 1, wherein the curable resin contains a compound having two or more (meth)acryloyl groups in one molecule.

7. 7. The sealant for optical devices according to claim 6, wherein the content of the terpene resin is 0.5 parts by mass or more and 25 parts by mass or less per 100 parts by mass of the compound having two or more (meth)acryloyl groups in one molecule.

8. 3. The sealant for optical devices according to claim 1, wherein the curable resin contains an epoxy compound.

9. 3. The sealant for optical devices according to claim 1, wherein the heat curing agent comprises a hydrazide compound or an amine adduct compound.

10. The sealant for optical devices according to claim 1 or 2, which is used in the production of a liquid crystal display element.

11. The sealant for optical devices according to claim 10, which is used in the production of a liquid crystal display element by a liquid crystal dropping method.

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