Sealing agent for liquid crystal element

Abstract

The object of this invention is to provide a sealant for liquid crystal elements that exhibits excellent adhesion and moisture permeability prevention, and which, upon curing, becomes a low elastic modulus. This invention is a sealant for liquid crystal elements comprising a curable resin, a polymerization initiator, and a thermosetting agent. The curable resin comprises an epoxy compound and a (meth)acrylic acid compound. The epoxy compound comprises a bisphenol-type epoxy compound and an isocyanuric acid compound having epoxy groups. The content of the isocyanuric acid compound having epoxy groups is 0.1 parts by weight or more and 25 parts by weight or less, relative to 100 parts by weight of the bisphenol-type epoxy compound.

Description

Technical Field

[0001] This invention relates to sealants for liquid crystal elements. Background Technology

[0002] In recent years, liquid crystal display (LCD) elements have been widely used as display components characterized by their thinness, light weight, and low power consumption. Additionally, liquid crystal dimming elements, which utilize liquid crystal materials, are widely used as dimming elements that change the transmittance of light by applying voltage. In such LCD elements and liquid crystal dimming elements, sealants are typically used in the bonding of various components and the sealing of the liquid crystal.

[0003] For example, as a manufacturing method for liquid crystal display elements, from the viewpoint of shortening production cycle time and optimizing the amount of liquid crystal used, a liquid crystal dispensing method, known as the drop-casting method, which uses a sealant and is disclosed in Patent Documents 1 and 2, is employed. In the drop-casting method, firstly, a sealant is applied to one of two electrode-bearing substrates to form a frame-shaped sealing pattern. Then, while the sealant is not cured, tiny droplets of liquid crystal are added into the sealing frame of the substrate. Under vacuum, the other substrate is overlapped, and the sealant is cured to produce a liquid crystal display element. Currently, this drop-casting method has become the mainstream manufacturing method for liquid crystal display elements.

[0004] In addition, for example, Patent Document 3 discloses a sealant containing an epoxy compound as a sealant for the liquid crystal layer surrounding the dimming unit.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2001-133794

[0008] Patent Document 2: International Publication No. 02 / 092718

[0009] Patent Document 3: Japanese Patent Application Publication No. 2021-117456 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] Especially in sealants used in high-end liquid crystal display components, there are further requirements for adhesion (particularly adhesion to both glass and alignment film) and moisture-proof properties to prevent water ingress. Furthermore, in recent years, for devices using dimming elements, there has been an increasing demand for reliability in high-temperature and high-humidity environments. On the other hand, in large displays and large devices using dimming elements, after the substrate is bonded with sealant, warping and flexing can easily occur due to the substrate's own weight. To suppress peeling and display defects caused by this, the sealant must have a low modulus of elasticity after curing. However, these characteristics are often compromised, making it difficult to manufacture a liquid crystal component sealant that offers excellent adhesion and moisture-proof properties while also having a low modulus of elasticity after curing.

[0012] The purpose of this invention is to provide a sealant for liquid crystal elements that has excellent adhesion and moisture-proof properties and becomes a low elastic modulus after curing.

[0013] Methods for solving problems

[0014] This disclosure 1 is a sealant for liquid crystal elements, comprising a curable resin, a polymerization initiator, and a thermosetting agent. The curable resin comprises an epoxy compound and a (meth)acrylic acid compound. The epoxy compound comprises a bisphenol type epoxy compound and an isocyanuric acid compound having an epoxy group. The content of the isocyanuric acid compound having an epoxy group is 0.1 parts by mass or more and 25 parts by mass or less, relative to 100 parts by mass of the bisphenol type epoxy compound.

[0015] This disclosure 2 is a sealant for liquid crystal elements according to this disclosure 1, wherein the epoxy-based isocyanuric acid compound comprises at least one selected from the group consisting of monoallyl diglycidyl isocyanurate and diallyl monoglycidyl isocyanurate.

[0016] This disclosure 3 is a sealant for liquid crystal elements according to disclosure 1 or 2, wherein the above-mentioned (meth)acrylic acid compound comprises a compound having one (meth)acryloyl group and at least one hydroxyl group in one molecule.

[0017] This disclosure 4 is a sealant for liquid crystal elements of disclosures 1, 2 or 3, which also contains organic fillers.

[0018] This disclosure 5 is a sealant for liquid crystal elements of disclosures 1, 2, 3 or 4, and it also contains a silane coupling agent.

[0019] The present invention will be described in detail below.

[0020] The inventors investigated the use of a bisphenol-type epoxy compound and an isocyanuric acid compound with epoxy groups as the epoxy compound in a specific ratio for a sealant for liquid crystal elements containing an epoxy compound and a (meth)acrylic acid compound as the curable resin. The results showed that a sealant for liquid crystal elements with excellent adhesion and moisture permeability prevention, and which cures to a low elastic modulus, was obtained, thus completing this invention.

[0021] The sealant for liquid crystal elements of the present invention contains a curable resin.

[0022] The aforementioned curable resins contain epoxy compounds and (meth)acrylic compounds.

[0023] It should be noted that in this specification, "(meth)acrylic acid" refers to acrylic acid or methacrylic acid, and "(meth)acrylic acid compounds" refers to compounds having a (meth)acryloyl group, excluding some (meth)acrylic acid modified epoxy compounds described later.

[0024] The aforementioned epoxy compounds include bisphenol-type epoxy compounds and isocyanuric acid compounds having epoxy groups. By combining the aforementioned bisphenol-type epoxy compounds and the aforementioned isocyanuric acid compounds having epoxy groups in amounts described later, the sealant for liquid crystal elements of the present invention exhibits excellent adhesion and moisture permeability prevention, and becomes a low elastic modulus after curing.

[0025] Examples of bisphenol-type epoxy compounds include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol E type epoxy compounds, bisphenol S type epoxy compounds, and 2,2'-diallylbisphenol A type epoxy compounds.

[0026] Alternatively, partially (meth)acrylic acid-modified bisphenol-type epoxy compounds can be used as the aforementioned bisphenol-type epoxy compounds.

[0027] Examples of partially (meth)acrylic acid modified bisphenol type epoxy compounds include partially (meth)acrylic acid modified bisphenol A type epoxy compounds, partially (meth)acrylic acid modified bisphenol F type epoxy compounds, and partially (meth)acrylic acid modified bisphenol E type epoxy compounds.

[0028] It should be noted that, in this specification, the term "partially (meth)acrylic acid modified epoxy compound" refers to a compound obtained by reacting a portion of the epoxy groups of an epoxy compound having two or more epoxy groups in one molecule with (meth)acrylic acid, resulting in a compound having one or more epoxy groups and one or more (meth)acryloyl groups in one molecule. Furthermore, in this specification, the term "(meth)acryloyl group" refers to acryloyl group or methacryloyl group.

[0029] The preferred lower limit for the content of the bisphenol-type epoxy compound in 100 parts by weight of the curable resin is 10 parts by weight, and the preferred upper limit is 40 parts by weight. By making the content of the bisphenol-type epoxy compound 10 parts by weight or more, the resulting sealant for liquid crystal elements exhibits superior adhesion. By making the content of the bisphenol-type epoxy compound 40 parts by weight or less, the resulting sealant for liquid crystal elements exhibits superior moisture permeability prevention and a lower elastic modulus after curing. A more preferred lower limit for the content of the bisphenol-type epoxy compound is 20 parts by weight, and a more preferred upper limit is 30 parts by weight.

[0030] The aforementioned isocyanuric acid compounds with epoxy groups have one or more epoxy groups in one molecule. Preferably, the aforementioned isocyanuric acid compounds with epoxy groups have three or fewer epoxy groups in one molecule, more preferably one or two epoxy groups.

[0031] Specifically, examples of the epoxy-based isocyanuric acid compounds mentioned above include monoallyl diglycidyl isocyanurate, diallyl monoglycidyl isocyanurate, and triglycidyl isocyanurate. Among these, from the perspective of obtaining a sealant for liquid crystal elements that exhibits superior adhesion and moisture-proof properties, the epoxy-based isocyanuric acid compounds preferably include at least one selected from the group consisting of monoallyl diglycidyl isocyanurate and diallyl monoglycidyl isocyanurate.

[0032] The content of the epoxy-based isocyanuric acid compound is limited to 0.1 parts by mass and 25 parts by mass relative to 100 parts by mass of the bisphenol-type epoxy compound. By ensuring that the content of the epoxy-based isocyanuric acid compound is 0.1 parts by mass or more relative to 100 parts by mass of the bisphenol-type epoxy compound, the sealant for liquid crystal elements of the present invention has a low elastic modulus after curing. By ensuring that the content of the epoxy-based isocyanuric acid compound is 25 parts by mass or less relative to 100 parts by mass of the bisphenol-type epoxy compound, the sealant for liquid crystal elements of the present invention exhibits excellent adhesion and moisture permeability prevention. The preferred lower limit of the content of the epoxy-based isocyanuric acid compound relative to 100 parts by mass of the bisphenol-type epoxy compound is 1 part by mass, the preferred upper limit is 15 parts by mass, the more preferred lower limit is 4 parts by mass, and the more preferred upper limit is 11 parts by mass.

[0033] Examples of the aforementioned (meth)acrylic acid compounds include (meth)acrylate compounds, epoxy (meth)acrylates, and urethane (meth)acrylates.

[0034] It should be noted that in this specification, "(meth)acrylate" refers to acrylate or methacrylate, and "epoxy (meth)acrylate" refers to a compound formed by reacting all the epoxy groups in an epoxy compound with (meth)acrylic acid.

[0035] Examples of monofunctional (meth)acrylate compounds include, for instance, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, isooctyl methacrylate, isononyl methacrylate, isodecanyl methacrylate, lauryl methacrylate, isomyrmethyl methacrylate, stearyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 4-hydroxybutyl methacrylate, 2-hydroxy-3-phenoxypropyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, dicyclopentenyl methacrylate, benzyl methacrylate, 2-methoxyethyl methacrylate, and so on. 2-Ethoxyethyl acrylate, 2-Butoxyethyl (meth)acrylate, 2-Phenoxyethyl (meth)acrylate, Methoxyethylene glycol (meth)acrylate, Methoxy polyethylene glycol (meth)acrylate, Phenoxydiethylene glycol (meth)acrylate, Phenoxy polyethylene glycol (meth)acrylate, Tetrahydrofurfuryl (meth)acrylate, Ethyl carbitol (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-meth)acrylate -Tetrafluoropropyl ester, (meth)acrylate 1H,1H,5H-octafluoropentyl ester, imide (meth)acrylate, (meth)acrylate dimethylaminoethyl ester, (meth)acrylate diethylaminoethyl ester, 2-(meth)acryloyloxyethyl succinic acid, 2-(meth)acryloyloxyethyl hexahydrophthalic acid, 2-(meth)acryloyloxyethyl 2-hydroxypropyl phthalate, 2-(meth)acryloyloxyethyl phosphate, (meth)acrylate glycidyl ester, etc.

[0036] Furthermore, examples of difunctional compounds among the aforementioned (meth)acrylate 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, and tripropylene glycol di(meth)acrylate. Polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethylene oxide addition bisphenol A di(meth)acrylate, propylene oxide addition bisphenol A di(meth)acrylate, ethylene oxide addition bisphenol F di(meth)acrylate, dihydroxymethyldicyclopentadienyl di(meth)acrylate, ethylene oxide modified isocyanuric acid di(meth)acrylate, 2-hydroxy-3-(meth)acryloyloxypropyl (meth)acrylate, carbonate glycol di(meth)acrylate, polyether glycol di(meth)acrylate, polyester glycol di(meth)acrylate, polycaprolactone glycol di(meth)acrylate, polybutadiene glycol di(meth)acrylate, etc.

[0037] In addition, examples of the above-mentioned (meth)acrylate compounds with three or more functions include trimethylolpropane tri(meth)acrylate, ethylene oxide addition trimethylolpropane tri(meth)acrylate, propylene oxide addition trimethylolpropane tri(meth)acrylate, caprolactone-modified trimethylolpropane tri(meth)acrylate, ethylene oxide addition isocyanuric acid tri(meth)acrylate, glycerol tri(meth)acrylate, propylene oxide addition glycerol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, tri(meth)acryloyloxyethyl phosphate, bis(trimethylolpropane)tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0038] Examples of the aforementioned epoxy (meth)acrylates include substances obtained by reacting an epoxy compound with (meth)acrylate in the presence of a basic catalyst using conventional methods.

[0039] Examples of epoxy compounds that can be used as raw materials for the synthesis of the aforementioned epoxy (meth)acrylates include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol E type epoxy compounds, bisphenol S type epoxy compounds, 2,2'-diallyl bisphenol A type epoxy compounds, hydrogenated bisphenol type epoxy compounds, propylene oxide addition bisphenol A type epoxy compounds, resorcinol type epoxy compounds, biphenyl type epoxy compounds, thioether type epoxy compounds, diphenyl ether type epoxy compounds, dicyclopentadiene type epoxy compounds, naphthyl type epoxy compounds, phenolic varnish type epoxy compounds, o-cresol phenolic varnish type epoxy compounds, dicyclopentadiene phenolic varnish type epoxy compounds, biphenyl phenolic varnish type epoxy compounds, naphthol phenolic varnish type epoxy compounds, glycidylamine type epoxy compounds, alkyl polyol type epoxy compounds, rubber modified epoxy compounds, and glycidyl ester compounds.

[0040] Commercially available examples of the aforementioned epoxy (meth)acrylates include those manufactured by Daicel-Allnex, Shin-Nakamura Chemical Industry Co., Ltd., Kyoeisha Chemical Co., Ltd., and Nagase ChemteX Co., Ltd.

[0041] Examples of 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, EBECRYL RDX63182, and KRM8076.

[0042] Examples of epoxy (meth)acrylates manufactured by Shin-Nakamura Chemical Industry Co., Ltd. include EA-1010, EA-1020, EA-5323, EA-5520, EA-CHD, and EMA-1020.

[0043] Examples of epoxy (meth)acrylates manufactured by Kyoei 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.

[0044] Examples of epoxy (meth)acrylates manufactured by Nagase ChemteX include: DENACOL ACRYLATE DA-141, DENACOL ACRYLATE DA-314, DENACOL ACRYLATE DA-911, etc.

[0045] The aforementioned urethane (meth)acrylates can be obtained, for example, by reacting an isocyanate compound with a (meth)acrylate derivative having a hydroxyl group in the presence of a catalytic amount of a tin-based compound.

[0046] Examples of isocyanate compounds that can serve as raw materials for the aforementioned urethane (meth)acrylates include isophorone diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, diphenylmethane-4,4'-diisocyanate (MDI), hydrogenated MDI, polymerized MDI, 1,5-naphthalene diisocyanate, norbornene diisocyanate, bitoluidine diisocyanate, phenylmethylene diisocyanate (XDI), hydrogenated XDI, lysine diisocyanate, triphenylmethane triisocyanate, tri(isocyanate phenyl)thiophosphate, tetramethylphenylmethylene diisocyanate, and 1,6,11-undecane triisocyanate.

[0047] Alternatively, the isocyanate compound used as a raw material for the aforementioned urethane (meth)acrylate can be a chain-extended isocyanate compound obtained by reacting a polyol with an excess of the isocyanate compound.

[0048] Examples of the aforementioned polyols include ethylene glycol, propylene glycol, glycerin, sorbitol, trimethylolpropane, carbonate glycol, polyether glycol, polyester glycol, and polycaprolactone glycol.

[0049] Examples of the above-mentioned (meth)acrylic acid derivatives having hydroxyl groups include hydroxyalkyl (meth)acrylic acid esters, mono(meth)acrylic acid esters of diols, mono(meth)acrylic acid esters or di(meth)acrylic acid esters of triols, epoxy (meth)acrylic acid esters, etc.

[0050] Examples of hydroxyalkyl esters of (meth)acrylate include 2-hydroxyethyl ester, 2-hydroxypropyl ester, 2-hydroxybutyl ester, and 4-hydroxybutyl ester.

[0051] Examples of the aforementioned diols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and polyethylene glycol.

[0052] Examples of the aforementioned triols include trimethylolethane, trimethylolpropane, and glycerol.

[0053] Examples of the aforementioned epoxy (meth)acrylates include, for example, bisphenol A type epoxy (meth)acrylates.

[0054] Commercially available products among the aforementioned urethane (meth)acrylates include, for example, urethane (meth)acrylates manufactured by Toa Synthetic Co., Ltd., urethane (meth)acrylates manufactured by Daicel-Allnex Co., Ltd., urethane (meth)acrylates manufactured by Negami Kogyo Co., Ltd., urethane (meth)acrylates manufactured by Shin-Nakamura Chemical Co., Ltd., and urethane (meth)acrylates manufactured by Kyoeisha Chemical Co., Ltd.

[0055] Examples of urethane (meth) acrylates manufactured by the aforementioned Dong-A Synthetic Co., Ltd. include M-1100, M-1200, M-1210, and M-1600.

[0056] Examples of 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.

[0057] Examples of the urethane (meth)acrylates manufactured by the aforementioned Nezumi 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, Art Resin UN-9000H, etc.

[0058] Examples of urethane (meth)acrylates manufactured by Shin-Nakamura Chemical Industry 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.

[0059] Examples of 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.

[0060] To improve adhesion to the interface, the aforementioned (meth)acrylic acid compounds preferably contain hydrogen-bonded functional groups, more preferably compounds having one (meth)acryloyl group and at least one hydroxyl group per molecule, and particularly preferably 2-hydroxy-3-phenoxypropyl (meth)acrylate. Furthermore, the aforementioned (meth)acrylic acid compounds also preferably contain the aforementioned epoxy (meth)acrylate, and more preferably a combination of the aforementioned compound having one (meth)acryloyl group and at least one hydroxyl group per molecule and the aforementioned epoxy (meth)acrylate.

[0061] The preferred lower limit for the content of the aforementioned (meth)acrylic acid compound in 100 parts by weight of the curable resin is 30 parts by weight, and the preferred upper limit is 90 parts by weight. By setting the content of the aforementioned (meth)acrylic acid compound within this range, the resulting sealant for liquid crystal elements exhibits superior curability and adhesion, as well as excellent low liquid crystal contamination. A more preferred lower limit for the content of the aforementioned (meth)acrylic acid compound is 40 parts by weight, and a more preferred upper limit is 80 parts by weight.

[0062] The preferred lower limit for the content of the curable resin in 100 parts by weight of the sealant for liquid crystal elements of the present invention is 50 parts by weight, and the preferred upper limit is 95 parts by weight. By setting the content of the curable resin in this range, the sealant for liquid crystal elements exhibits superior curability and adhesion. A more preferred lower limit for the content of the curable resin is 60 parts by weight, and a more preferred upper limit is 85 parts by weight.

[0063] The sealant for liquid crystal elements of the present invention contains a polymerization initiator.

[0064] Examples of polymerization initiators include photoradical polymerization initiators that generate free radicals through light irradiation and thermal radical polymerization initiators that generate free radicals through heating.

[0065] Examples of photoradical polymerization initiators include benzophenone compounds, acetophenone compounds, acylphosphine oxide compounds, dicene compounds, oxime ester compounds, benzoin ether compounds, and thioxanone compounds.

[0066] Specifically, examples of photoradical polymerization initiators include 1-hydroxycyclohexylphenyl ketone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-((4-methylphenyl)methyl)-1-(4-(4-morpholino)phenyl)-1-butanone, 2,2-dimethoxy-1,2-diphenylethane-1-one, and bis(2,4,6-trimethylbenzoyl) Phosphorus oxyphenyl, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropane-1-one, 1-(4-(2-hydroxyethoxy)-phenyl)-2-hydroxy-2-methyl-1-propane-1-one, 1-(4-(phenylthio)phenyl)-1,2-octanedione 2-(O-benzoyl oxime), 2,4,6-trimethylbenzoyl diphenylphosphine oxide, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, etc.

[0067] The above-mentioned photoradical polymerization initiators can be used alone or in combination of two or more.

[0068] Examples of thermal free radical polymerization initiators include those composed of azo compounds and organic peroxides. From the viewpoint of suppressing liquid crystal contamination, initiators composed of azo compounds (hereinafter also referred to as "azo initiators") are preferred.

[0069] The above-mentioned thermal free radical polymerization initiators can be used alone or in combination of two or more.

[0070] Commercially available azo initiators mentioned above include, for example, VPE-0201, VPE-0401, VPE-0601, VPS-0501, VPS-1001, V-65, and V-501 (all manufactured by Fujifilm and Kojun Pharmaceutical Co., Ltd.).

[0071] Examples of the aforementioned organic peroxides include: peroxide ketones, peroxide ketals, hydrogen peroxide, dialkyl peroxides, peroxide esters, diacyl peroxides, and peroxydicarbonates.

[0072] The preferred lower limit of the content of the polymerization initiator relative to 100 parts by weight of the curable resin is 0.01 parts by weight, and the preferred upper limit is 10 parts by weight. By setting the content of the polymerization initiator within this range, the resulting sealant for liquid crystal elements exhibits superior storage stability and curability. A more preferred lower limit of the content of the polymerization initiator is 0.1 parts by weight, and a more preferred upper limit is 5 parts by weight.

[0073] The sealant for liquid crystal elements of the present invention contains a thermosetting agent.

[0074] Examples of thermosetting agents include organic acid hydrazides, imidazole derivatives, amine compounds, polyphenolic compounds, and acid anhydrides. Among these, organic acid hydrazides are preferred.

[0075] The above-mentioned thermosetting agents can be used alone or in combination of two or more.

[0076] Examples of the aforementioned organic acid hydrazides include sebacic acid dihydrazide, isophthalic acid dihydrazide, adipic acid dihydrazide, malonic acid dihydrazide, etc.

[0077] Commercially available examples of the aforementioned organic acid hydrazides include those manufactured by Otsuka Chemical Co., Ltd., and those manufactured by Ajinomoto Fine-Techno Co., Inc.

[0078] Examples of organic acid hydrazides manufactured by Otsuka Chemical Co., Ltd. include SDH, ADH, and MDH.

[0079] Examples of organic acid hydrazides manufactured by Ajinomoto Fine-Techno Co., Inc. include, for example, AJICURE VDH, AJICURE VDH-J, AJICURE UDH, and AJICURE UDH-J.

[0080] The preferred lower limit of the content of the aforementioned thermosetting agent relative to 100 parts by weight of the aforementioned curable resin is 1 part by weight, and the preferred upper limit is 50 parts by weight. By keeping the content of the aforementioned thermosetting agent within this range, the coatability and storage stability of the resulting sealant for liquid crystal elements can be maintained without deterioration, and the thermosetting properties are superior. A more preferred upper limit of the content of the aforementioned thermosetting agent is 30 parts by weight.

[0081] The sealant for liquid crystal elements of the present invention preferably further contains organic fillers. By containing the above-mentioned organic fillers, the resulting sealant for liquid crystal elements exhibits superior adhesion to the alignment film and is more likely to have a low elastic modulus after curing.

[0082] Examples of organic fillers include polyester microparticles, polyurethane microparticles, vinyl polymer microparticles, and (meth)acrylic polymer microparticles. Among these, (meth)acrylic polymer microparticles are preferred. Furthermore, the aforementioned organic fillers may have a core-shell structure.

[0083] The preferred lower limit for the average particle size of the aforementioned organic filler is 0.1 μm, and the preferred upper limit is 5 μm. By setting the average particle size of the aforementioned organic filler within this range, it is easier to maintain the coatability of the liquid crystal element with the sealant, and it has a low elastic modulus after curing. A more preferred lower limit for the average particle size of the aforementioned organic filler is 0.3 μm, and a more preferred upper limit is 2 μm.

[0084] It should be noted that the average particle size of the aforementioned organic filler can be measured, for example, using a particle size distribution measuring device, by dispersing the organic filler in a solvent (water, organic solvent, etc.). Examples of such particle size distribution measuring devices include the NICOMP 380ZLS (manufactured by PARTICLE SIZING SYSTEMS).

[0085] The preferred lower limit for the content of the organic filler relative to 100 parts by weight of the curable resin is 1 part by weight, and the preferred upper limit is 40 parts by weight. By setting the content of the organic filler within this range, it is easier to maintain the coating properties of the obtained liquid crystal element through sealing, and it has a low elastic modulus after curing. The more preferred lower limit for the content of the organic filler is 3 parts by weight, and the more preferred upper limit is 30 parts by weight.

[0086] The sealant for liquid crystal elements of the present invention may further contain inorganic fillers for purposes such as viscosity adjustment, further improvement of adhesion based on stress dispersion effect, and improvement of linear expansion rate.

[0087] Examples of inorganic fillers mentioned above include silica, talc, glass beads, asbestos, gypsum, diatomaceous earth, montmorillonite, 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.

[0088] The preferred lower limit for the content of the inorganic filler relative to 100 parts by weight of the curable resin is 10 parts by weight, and the preferred upper limit is 40 parts by weight. By keeping the content of the inorganic filler within this range, coating properties are maintained, and the effects of improved adhesion are even better. The more preferred lower limit for the content of the inorganic filler is 20 parts by weight, and the more preferred upper limit is 30 parts by weight.

[0089] The sealant for liquid crystal elements of the present invention preferably further contains a silane coupling agent. The aforementioned silane coupling agent primarily functions as an adhesive aid for further and better bonding the sealant for liquid crystal elements to the substrate, etc.

[0090] As the aforementioned silane coupling agents, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, and 3-isocyanate-propyltrimethoxysilane are preferred, for example. They have excellent effects in improving adhesion to substrates, etc., and can also suppress the outflow of curable resin into the liquid crystal.

[0091] The above-mentioned silane coupling agents can be used alone or in combination of two or more.

[0092] The preferred lower limit for the content of the silane coupling agent relative to 100 parts by weight of the curable resin is 0.1 parts by weight, and the preferred upper limit is 5 parts by weight. By setting the content of the silane coupling agent within this range, the effect of improving adhesion is more excellent. A more preferred lower limit for the content of the silane coupling agent is 0.3 parts by weight, and a more preferred upper limit is 2 parts by weight.

[0093] The sealant for liquid crystal elements of the present invention may also contain additives such as light-blocking agents, stress-relieving agents, reactive diluents, thixotropic agents, spacers, curing accelerators, defoamers, leveling agents, and polymerization inhibitors as needed.

[0094] As a method for manufacturing the sealant for the liquid crystal element of the present invention, examples include a method of mixing a curable resin, a polymerization initiator, a thermosetting agent, and additives such as a silane coupling agent added as needed, using a homogenizer, a homogenizer, a universal mixer, a planetary mixer, a kneader, a three-roll mill, or other mixers.

[0095] The sealant for liquid crystal elements of the present invention is preferably used at an irradiation wavelength of 365 nm and an illuminance of 100 mW / cm². 2The cured product obtained by heating at 120°C for 1 hour after 30 seconds of ultraviolet light exposure has a storage modulus of less than 3.5 GPa at 25°C. By achieving a storage modulus of less than 3.5 GPa, the sealant for liquid crystal elements of the present invention exhibits excellent performance in suppressing peeling and display defects when used in large displays, large equipment using dimming elements, etc. More preferably, the storage modulus is less than 3.0 GPa.

[0096] Furthermore, from the viewpoint of adhesion when bonded to the object, the preferred lower limit of the above-mentioned energy storage modulus is 0.1 GPa, and the more preferred lower limit is 1.0 GPa.

[0097] It should be noted that the above-mentioned energy storage modulus can be measured using a dynamic viscoelasticity measuring device (such as the "DVA-200" manufactured by IT Measurement & Control Co., Ltd.), under the conditions of tensile mode, test piece width of 5 mm, thickness of 0.35 mm, holding width of 25 mm, heating rate of 10 °C / min, and frequency of 5 Hz.

[0098] By mixing conductive microparticles into the sealant for liquid crystal elements of the present invention, a material with both top and bottom conductive properties can be manufactured.

[0099] As the aforementioned conductive particles, metal spheres, particles with a conductive metal layer formed on the surface of resin particles, etc., can be used. Among them, particles with a conductive metal layer formed on the surface of resin particles are preferred because the excellent elasticity of resin particles allows for conductive connections without damaging the transparent substrate, etc.

[0100] As for the liquid crystal element obtained using the liquid crystal element sealant of the present invention, a liquid crystal element with a narrow bezel design is preferred. Specifically, the width of the frame portion surrounding the liquid crystal display section is preferably 2 mm or less.

[0101] When manufacturing the above-mentioned liquid crystal element, the coating width of the sealant for the liquid crystal element of the present invention is preferably 1 mm or less.

[0102] Examples of liquid crystal elements manufactured using the liquid crystal element sealant of the present invention include liquid crystal display elements and liquid crystal dimming elements.

[0103] The sealant for liquid crystal elements of the present invention is suitable for use in the manufacture of liquid crystal elements based on the liquid crystal dispensing method. Examples of methods for manufacturing the aforementioned liquid crystal elements by the liquid crystal dispensing method include the following.

[0104] First, the following steps are performed: the liquid crystal element sealant of the present invention is applied to a substrate by screen printing, dispensing, or other methods to form a frame-shaped sealing pattern. Next, the following steps are performed: while the liquid crystal element sealant of the present invention is not cured, tiny droplets of liquid crystal are applied to the entire surface within the frame of the sealing pattern, and other substrates are immediately overlapped. Then, the sealing pattern is irradiated with ultraviolet light or other light to temporarily cure the liquid crystal element sealant, and the temporarily cured liquid crystal element sealant is heated to fully cure it. By this method, a liquid crystal element can be obtained.

[0105] The effects of the invention

[0106] According to the present invention, a sealant for liquid crystal elements with excellent adhesion and moisture permeability prevention, and which becomes a low elastic modulus after curing, can be provided. Detailed Implementation

[0107] The present invention is illustrated in more detail by the following examples, but the present invention is not limited to these examples.

[0108] (Examples 1-17, Comparative Examples 1-6)

[0109] According to the mixing ratios recorded in Tables 1-3, each material was stirred using a planetary mixer (manufactured by THINKY Corporation, "Awatori Rentaro") and then uniformly mixed using a ceramic three-roll mill to obtain the sealants for liquid crystal elements of Examples 1-17 and Comparative Examples 1-6.

[0110] <Evaluation>

[0111] The sealant used to obtain the liquid crystal elements was evaluated as follows. The results are shown in Tables 1-3.

[0112] (Adhesion to glass substrates with ITO film)

[0113] Using a planetary stirring apparatus, spacer particles (manufactured by Sekisui Chemicals Co., Ltd., "Micropearl SP-2050") with an average particle size of 5 μm were uniformly dispersed at 1 part by mass relative to 100 parts by mass of the obtained liquid crystal element sealant. A very small amount of the liquid crystal element sealant containing the dispersed spacer particles was placed in the center of a glass substrate with an ITO film, and another glass substrate of the same type with an ITO film was stacked on top. The liquid crystal element sealant was spread out and irradiated with a metal halide lamp at a wavelength of 365 nm and an illuminance of 100 mW / cm². 2 After 30 seconds of ultraviolet light exposure, the liquid crystal element is heated at 120°C for 1 hour to cure with a sealant, resulting in an adhesion test piece. The adhesion strength (adhesion force on a glass substrate with an ITO film) of the obtained adhesion test piece is measured using a tensiometer.

[0114] The bond strength is 3.0 kgf / cm. 2 The above situation is rated as "◎", and 2.5 kgf / cm 2 Above and below 3.0 kgf / cm 2 The condition is rated as "○", meaning it is less than 2.5 kgf / cm². 2 The evaluation is marked as "×", which assesses the adhesion to the glass substrate with the ITO film.

[0115] (Adhesion to substrates with alignment films)

[0116] An alignment film-coated substrate was prepared by spin-coating an imide resin onto a glass substrate with an ITO film, pre-baking at 80°C, and then firing at 230°C. SE7492 (manufactured by Nissan Chemical Co., Ltd.) was used as the imide resin. An adhesion test piece was obtained using the alignment film-coated substrate instead of the ITO film-coated glass substrate, except that the adhesion to the ITO film-coated glass substrate was the same as described above. The adhesion strength (adhesion force to the alignment film-coated substrate) of the obtained adhesion test pieces was measured using a tensiometer.

[0117] The bond strength is 2.0 kgf / cm. 2 The above situation is rated as "◎", and 1.5 kgf / cm 2 Above and less than 2.0 kgf / cm 2 The condition is rated as "○", meaning less than 1.5 kgf / cm³. 2 The evaluation is "×", which assesses the adhesion to the substrate with the alignment film.

[0118] (moisture permeability prevention)

[0119] The obtained liquid crystal elements were coated with a sealant onto a smooth release film with a thickness of 200-300 μm using a coating machine. Next, a metal halide lamp was used to irradiate the film at a wavelength of 365 nm and an illuminance of 100 mW / cm². 2 After 30 seconds of exposure to ultraviolet light, the liquid crystal element is heated at 120°C for 1 hour to cure with a sealant, thus obtaining a film for moisture permeability testing. A moisture permeability testing cup is prepared according to the method of JIS Z 0208, Moisture Permeability Test Method for Moisture-proof Packaging Materials (Cup Method). The obtained moisture permeability testing film is then installed in the cup and placed in a constant temperature and humidity oven at 80°C and 90%RH to measure the moisture permeability.

[0120] The obtained moisture permeability value is less than 70 g / m³. 2 The 24-hour condition is rated as "◎", with a concentration of 70g / m 2 • More than 24 hours and less than 80g / m 2 The 24-hour condition is rated as "○", with 80g / m2 • For conditions lasting more than 24 hours, the rating is “×”, which evaluates the breathability and moisture-proofing properties.

[0121] (Elastic modulus)

[0122] For the sealant used in the obtained liquid crystal element, a metal halide lamp was used for irradiation at a wavelength of 365 nm and an illuminance of 100 mW / cm². 2 After 30 seconds of exposure to ultraviolet light, the sample was heated at 120°C for 1 hour to obtain a cured product. The cured product was then subjected to dynamic viscoelasticity testing using a dynamic viscoelasticity measuring device under the following conditions: tensile mode, test piece width 5 mm, thickness 0.35 mm, holding width 25 mm, heating rate 10°C / min, and frequency 5 Hz. The storage modulus at 25°C was measured.

[0123] The energy storage modulus is evaluated as “◎” for cases with a modulus less than 3.0 GPa, as “○” for cases with a modulus greater than 3.0 GPa but less than 3.5 GPa, and as “×” for cases with a modulus greater than 3.5 GPa. The elastic modulus is then evaluated.

[0124] [Table 1]

[0125]

[0126] [Table 2]

[0127]

[0128] [Table 3]

[0129]

[0130] Industrial availability

[0131] According to the present invention, a sealant for liquid crystal elements with excellent adhesion and moisture permeability prevention, and which becomes a low elastic modulus after curing, can be provided.

Claims

1. A sealant for liquid crystal elements, characterized in that, It contains curable resin, polymerization initiator and thermosetting agent. The curable resin comprises epoxy compounds and (meth)acrylic compounds. The epoxy compounds include bisphenol type epoxy compounds and isocyanuric acid compounds with epoxy groups. The content of the isocyanuric acid compound having an epoxy group is 0.1 parts by mass or more and 25 parts by mass or less, relative to 100 parts by mass of the bisphenol type epoxy compound.

2. The sealant for liquid crystal elements according to claim 1, wherein, The epoxy-containing isocyanuric acid compounds comprise at least one selected from the group consisting of monoallyl diglycidyl isocyanurate and diallyl monoglycidyl isocyanurate.

3. The sealant for liquid crystal elements according to claim 1 or 2, wherein, The (meth)acrylic acid compounds comprise compounds having one (meth)acryloyl group and at least one hydroxyl group in one molecule.

4. The sealant for liquid crystal elements according to claim 1, 2 or 3, further comprising organic fillers.

5. The sealant for liquid crystal elements according to claim 1, 2, 3 or 4, further comprising a silane coupling agent.

Images