TW201923017A - Sealant for display - Google Patents

Abstract

The present invention relates to a sealant for display used for an adhesive for electronic parts which can be applied to a flexible display or a curved display. More specifically, the present invention relates to a sealant for display containing a compound having a specific structure in the molecule. Since the sealant for display is compatible with both flexibility and low moisture permeability, it is useful as an adhesive for electronic components, particularly as a sealant for display. The sealant for display of the present invention contains a maleimide compound having an alkylene group of C10 to C50 in the molecule of a component (A), and the content of an epoxy (meth) acrylate compound is less than 5 mass%.

Description

 Display encapsulant  

The present invention relates to an encapsulant for display, which is applicable to a flexible display, a curved display. More specifically, it relates to an encapsulant for displays that satisfies a specific relationship between the glass transition temperature and the elastic modulus. The encapsulant for display is particularly useful as a packaging agent for a display having a flexible display or a curved shape because it can achieve both flexibility and low moisture permeability.

The sealing agent for a display can be, for example, a sealing agent for a liquid crystal display, an encapsulant for an organic EL display, an adhesive for a touch panel, or the like. The common point of these materials is that they are required to have excellent hardenability and have little exhaust gas and do not cause damage to the display element.

Moreover, recently, a curved display and a flexible display have been developed and manufactured. The substrate used for such a display is replaced with a rigid person such as a plastic film using a softness such as a plastic film (Patent Document 1).

Due to such a background, it is required that the encapsulant for a display be subjected to bending of a substrate or the like, that is, a property that is soft even after hardening.

On the other hand, in order to improve the softness of the cured product, it is effective to reduce the crosslinking density of the cured product. However, if the crosslink density is lowered, the moisture permeability is usually deteriorated. It is speculated that this is due to the fact that moisture is partially immersed in the loose portion of the network structure. Therefore, in order to ensure low moisture permeability, it is necessary to achieve the opposite characteristic of not lowering the crosslinking density, increasing the softness, or lowering the crosslinking density without deteriorating the moisture permeability.

Conventionally, development of an adhesive for display elements having flexibility has been carried out from the viewpoint of improving the adhesion strength. For example, Patent Document 2 discloses a liquid crystal sealing agent which is strong in adhesion to a glass substrate by containing a urethane (meth) acrylate having a specific structure. However, it has not been realized to have sufficient performance for responding to the above flexible substrate.

Patent Document 1: Japanese Laid-Open Patent Publication No. 2012-238005

Patent Document 2: JP-A-2016-24240

The present invention proposes an encapsulant having flexibility to the extent that it can be applied to a flexible display, a curved shape display, and also excellent in low moisture permeability.

As a result of intensive studies by the present inventors, it has been found that a specific maleimide compound is excellent in flexibility and low moisture permeability, and the present invention has been completed.

In the present specification, "(meth)acrylic acid" means "acrylic acid and/or methacrylic acid", and "(meth)acrylic acid radical" means "acrylic fluorenyl group and/or methacryl fluorenyl group". "The meaning." Moreover, the "liquid crystal sealing agent for liquid crystal dropping method" is also described only as "liquid crystal sealing agent" or "sealing agent".

That is, the present invention relates to:

[1] An encapsulant for display comprising a maleimide compound having a component (A) having a hydrocarbon group of C10 to C50 in a molecule, and a content of the epoxy (meth) acrylate compound of less than 5% by mass .

[2] The encapsulating agent for a display according to the above [1], further comprising a compound having a component (B) having an epoxy group in the molecule and having a number average molecular weight of 500 to 10,000.

[3] The encapsulating agent for a display according to the above [1], wherein the component (A) is a maleic imine compound represented by the following formula (1).

(In the formula (1), R ¹ represents a divalent crosslinking group having a hydrocarbon group of C10 to C50, etc.)

[4] The encapsulating agent for a display according to the above [3], wherein, in the formula (1), R ¹ is a group having a hetero ring.

[5] The encapsulating agent for a display according to any one of the above aspects, wherein the component (B) is a polybutadiene or a polyisoprene compound.

The encapsulating agent for a display according to any one of the above aspects, wherein the component (B) is a compound having a reactive double bond in the molecule.

[7] The encapsulating agent for a display according to any one of [1] to [6] further comprising a component (C) thiol compound.

[8] The encapsulating agent for a display according to the above [7], wherein the component (C) is a polyfunctional thiol compound.

[9] The encapsulating agent for a display according to any one of [1] to [8] further comprising the component (D) organic filler.

[10] The encapsulant for display according to the above [9], wherein the component (D) is selected from the group consisting of urethane microparticles, acrylic microparticles, styrene microparticles, styrene olefin microparticles, and polyfluorene microparticles. One or two or more organic fillers in the group formed.

[11] The encapsulating agent for a display according to any one of [1] to [10] further comprising the component (E) inorganic filler.

[12] The encapsulating agent for a display according to any one of [1] to [11] further comprising a component (F) decane coupling agent.

[13] The encapsulating agent for a display according to any one of [1] to [12] further comprising a component (G) thermosetting agent.

[14] The encapsulating agent for a display according to any one of [1] to [13] further comprising a component (H) photoradical polymerization initiator.

[15] The encapsulating agent for a display according to any one of [1] to [14] further comprising a component (I) thermal radical polymerization initiator.

[16] A liquid crystal display unit which is obtained by using the encapsulating agent for a display according to any one of the items [1] to [15].

The encapsulant for display of the present invention can be used as an adhesive for electronic parts, in particular, an encapsulant for displays, since it can achieve both flexibility and low moisture permeability.

 [(A) Maleimide compound having a hydrocarbon group of C10 to C50 in the molecule]  

The encapsulating agent for a display of the present invention contains a component (A) a maleimide compound having a hydrocarbon group of from C10 to C50 in the molecule (hereinafter, simply referred to as component (A)).

This compound exhibits flexibility and extensibility in the long-chain hydrocarbon group portion, and on the other hand, the portion which contributes to hardening is a maleimide group, so that low moisture permeability can be achieved.

The component (A) is preferably a maleic imine compound represented by the above formula (1). In the formula (1), R ¹ means a divalent crosslinking group having a hydrocarbon group of C10 to C50, which may be a C10 to C50 alkyl group, or may have another skeleton. When the alkyl group is C10 to C50, it may be a straight chain or a cyclic group, or an unsaturated group may be present in a chain form. Regarding the carbon number, it is more preferably C15 to C45, and particularly preferably C20 to C40. Further, when it has another skeleton, a substituted group such as a cyclic hydrocarbon group or a heterocyclic ring may, for example, be mentioned.

Among these R ¹ , a hydrocarbon group having a hetero ring as a substituent is preferred. This is due to the central portion of the skeleton, which also shows the strength of the adhesion to the substrate.

In the case of R ^{1 of the} component (A), the particularly preferred skeleton is represented by the following formula (2).

The above R ² means a linear hydrocarbon group of C10 to C50, preferably a hydrocarbon group having a cyclohexylene group in the chain.

Also, n denotes a repeating unit, and preferably 1 to 3.

 [Epoxy (meth) acrylate compound]  

The content of the epoxy (meth) acrylate compound of the encapsulant for display of the present invention is less than 5% by mass. This means that less than 5% by mass of the epoxy (meth) acrylate compound is added to the total amount of the encapsulant for display or substantially does not.

The epoxy (meth) acrylate compound is inferior in compatibility with the component (A). Moreover, although it is used for a general package for display, since it has a hydroxyl group in a molecule, it is unsuitable for the material which is compatible with the low moisture permeability and the softness.

 [(B) a compound having an epoxy group in the molecule and having a number average molecular weight of 500 to 10,000]  

The encapsulating agent for a display of the present invention may further contain a component (B) having an epoxy group in the molecule and having a number average molecular weight of 500 to 10,000 (hereinafter, simply referred to as component (B)).

Since the component (B) is excellent in compatibility with the component (A) and is soft in itself, it contributes to the softness, elongation, and low moisture permeability of the object to be solved by the present invention.

The number average molecular weight of the component (B) is preferably 500 or less from the viewpoint of the exhaust gas from the encapsulant for display or the liquid crystal contamination when used as a liquid crystal peripheral material (for example, a liquid crystal sealing agent). Good for 750, especially good for 1000.

Further, from the viewpoint of workability, the upper limit of the number average molecular weight of the component (B) is preferably 10,000, more preferably 8,000, and particularly preferably 6,000.

The component (B) is preferably polybutadiene or polyisoprene, and preferably has a reactive double bond in the molecule. This is due to the fact that by having a reactive double bond, the rapid reactivity of the radical can be exerted.

The component (B) can be obtained by oxidizing polybutadiene or polyisoprene. For the oxidation, for example, a known organic peroxide or hydrogen peroxide can be used.

Ingredients (B) are available from the market, for example, JP-100, JP-200, JP-400 (all manufactured by Japan Soda Co., Ltd.), EPOLEAD PB3600 (manufactured by DAICEL Co., Ltd.), and BF-1000 (made by ADEKA Co., Ltd.). , RICON-657 (CRAY VALLEY system).

 [(C) thiol compound]  

The encapsulating agent for a display of the present invention may further contain a component (C) thiol compound (hereinafter also referred to simply as component (C)). Since the component (C) reacts with the epoxy group of the component (A) and the reactive double bond, it is very useful when added.

The component (C) is not particularly limited as long as it has a thiol group in the molecule, but from the viewpoint of storage stability and reactivity, a thiol compound having a secondary thiol group is preferred.

Further, the number of thiol groups is preferably two or more (polyfunctional thiol compounds) in the molecule, and more preferably trifunctional or tetrafunctional.

When the sealing agent for a display of the present invention is used as an encapsulant for electronic parts, the thiol equivalent of the thiol compound is preferably 80 or more, and more preferably 100 or more, from the viewpoint of suppressing exhaust gas. Further, the molecular weight is preferably 250 or more, more preferably 500 or more.

The component (C) may be used singly or in combination of two or more. In the encapsulant for display of the present invention, when the component (C) is used, it is usually from 1 to 50% by mass, preferably from 5 to 25% by mass, based on the total amount of the encapsulant for display.

 [(D) Organic Filler]  

The encapsulating agent for a display of the present invention may further contain a component (D) organic filler (hereinafter also referred to simply as component (D)). Examples of the organic filler include urethane microparticles, acrylic microparticles, styrene microparticles, styrene olefin microparticles, and polyoxynium microparticles. Further, the polyoxynene fine particles are preferably KMP-594, KMP-597, KMP-598 (manufactured by Shin-Etsu Chemical Co., Ltd.), Trefil ^RTM E-5500, 9701, EP-2001 (manufactured by Toray Dow Corning Co., Ltd.), urethane. The ester microparticles are preferably JB-800T or HB-800BK (manufactured by Kasei Kogyo Co., Ltd.), and the styrene microparticles are preferably RABALON ^RTM T320C, T331C, SJ4400, SJ5400, SJ6400, SJ4300C, SJ5300C, SJ6300C (manufactured by Mitsubishi Chemical Corporation). The styrene olefin fine particles are preferably SEPTON ^RTM SEPS2004, SEPS2063.

These organic fillers may be used singly or in combination of two or more. Further, two or more kinds of core-shell structures may be used. Among these, acrylic fine particles and polyoxynized fine particles are preferable.

When the above acrylic fine particles are used, an acrylic rubber having a core-shell structure composed of two acrylic rubbers is preferable, and particularly preferably, the core layer is n-butyl acrylate and the shell layer is methyl methacrylate. It has ZEFIAC ^RTM F-351 sold by AICA Industries, Inc.

Further, examples of the polyoxynene fine particles include an organic polyoxyalkylene crosslinked product powder and a linear polydimethyloxane crosslinked powder. Further, the composite polyoxyxene rubber may, for example, be a layer of a polyoxyxylene resin coated with a polyoxyxylene resin (for example, a polyorganosilsesquioxane resin). Among these fine particles, a polyfluorene rubber which is particularly preferably a linear polydimethyl siloxane oxide crosslinked powder, or a polyfluorene resin coated with a linear polydimethyl methoxy oxane crosslinked powder Oxygen rubber microparticles. These may be used singly or in combination of two or more. Further, it is preferable that the shape of the rubber powder is a spherical shape having less viscosity and viscosity after the addition. In the encapsulant for display of the present invention, when the component (D) is used, it is usually 5 to 50% by mass, preferably 5 to 40% by mass based on the total amount of the encapsulant for display.

 [(E) Inorganic Filler]  

The encapsulating agent for a display of the present invention may further contain a component (E) inorganic filler (hereinafter, simply referred to as component (E)). The inorganic filler contained in the present invention may, for example, be cerium oxide, cerium carbide, cerium nitride, boron nitride, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, magnesia, oxidation. Zirconium, aluminum hydroxide, magnesium hydroxide, calcium citrate, aluminum silicate, lithium aluminum silicate, zirconium silicate, barium titanate, glass fiber, carbon fiber, molybdenum disulfide, asbestos, etc., preferably, for example, melting Cerium oxide, crystalline cerium oxide, cerium nitride, boron nitride, calcium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, aluminum hydroxide, calcium citrate, aluminum citrate, preferably cerium oxide , alumina, talc. These inorganic fillers may be used in combination of two or more kinds.

When the average particle diameter of the inorganic filler is too large, when a liquid crystal cell having a narrow gap is formed, the main cause of the problem such as formation of a gap at the time of bonding the upper and lower glass substrates is not good. Therefore, it is preferably 2000 nm or less. It is 1000 nm or less, more preferably 300 nm or less. Further, the lower limit is preferably about 10 nm, more preferably about 100 nm. The particle size can be measured by a laser diffraction/scattering particle size distribution analyzer (dry type) (manufactured by Seishin Co., Ltd., LMS-30).

In the encapsulant for display of the present invention, when an inorganic filler is used, it is usually 5 to 50% by mass, preferably 5 to 40% by mass based on the total amount of the liquid crystal sealing agent.

 [(F) decane coupling agent]  

The component (F) decane coupling agent (hereinafter, simply referred to as component (F)) may be added to the sealing agent for a display of the present invention to improve the strength and moisture resistance.

The component (F) may, for example, be 3-glycidoxypropyltrimethoxydecane, 3-glycidoxypropylmethyldimethoxydecane or 3-glycidoxypropylmethyl Diethoxydecane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxydecane, N-phenyl-γ-aminopropyltrimethoxydecane, N-(2-Amino B 3-aminopropylmethyldimethoxydecane, N-(2-aminoethyl) 3-aminopropylmethyltrimethoxydecane, 3-aminopropyltriethoxydecane , 3-mercaptopropyltrimethoxydecane, vinyltrimethoxydecane, N(2-(vinylbenzylamino)ethyl)3-aminopropyltrimethoxydecane hydrochloride, 3- Methyl propylene methoxy propyl trimethoxy decane, 3-chloropropyl methyl dimethoxy decane, 3-chloropropyl trimethoxy decane, and the like. These decane coupling agents are available in the KBM series and KBE series sold by Shin-Etsu Chemical Co., Ltd., etc., and can be easily obtained by the market. In the encapsulant for display of the present invention, when the component (F) is used, it is preferably 0.05 to 3% by mass based on the total amount of the encapsulant for display.

 [(G) Thermal Hardener]  

The encapsulating agent for a display of the present invention may further contain a component (G) thermosetting agent (hereinafter also referred to simply as component (G)). The component (G) is a nucleophilic reaction by not sharing an electron pair or an anion in the molecule, and examples thereof include a polyamine, a polyphenol, and an organic acid hydrazine compound. However, it is not limited to these. Among these, it is particularly preferable to use an organic acid hydrazine compound. For example, terephthalic acid, m-xylylene phthalate, dioxane 2,6-pyridinium dichloride, 2,6-pyridine dioxime, 1,2,4-benzene belonging to the aromatic hydrazine. Triterpenoids, tetramethylphosphonium 1,4,5,8-naphthoate, 1,2,4,5-benzenetetramethylguanidine, and the like. Moreover, in the case of an aliphatic hydrazine compound, for example, formazan, acetamidine, acetonide, acesulfonium, propylene dioxime, butyl hydrazine, pentane quinone, and hexamethylene oxime may be mentioned. , gypsum, hydrazine, 1,4-cyclohexanedihydro, 2,3-dihydroxybutane, 2-hydroxybutane, imine, hydrazine, N, N'-hexamethylene bis-carbazone, 2-hydroxy-1,2,3-propanetrimidine, nitrogen triacetin, cyclohexane trimethylhydrazine, 1,3-bis(decylcarbonyl) )- 5-isopropylethyl carbazide or the like having an intramethylene uregar skeleton [preferably having a phthalic acid carbendazim skeleton (a skeleton in which a carbon atom of the uremone ring is substituted with an isopropyl group)] a bismuth compound, tris(1-mercaptocarbonylmethyl)trimeric isocyanate, tris(2-mercaptocarbonylethyl)trimeric isocyanate, tris(1-mercaptocarbonylethyl)trimeric isocyanate, three ( 3-mercaptocarbonylpropyl)trimeric isocyanate, bis(2-mercaptocarbonylethyl)trimeric isocyanate, and the like. From the balance of hardening reactivity and potential, it is preferably meta-xylylene, propylenediamine, hexamethylene, tris(1-mercaptocarbonylmethyl)trimeric isocyanate, and tris(1-anthracene). Carbocarbonylethyl)trimeric isocyanate, tris(2-mercaptocarbonylethyl)trimeric isocyanate, tris(3-mercaptocarbonylpropyl)trimeric isocyanate, particularly preferably tris(2-mercaptocarbonylethyl) Trimeric isocyanate.

The component (G) may be used singly or in combination of two or more. In the encapsulant for display of the present invention, when the component (G) is used, it is usually from 0.1 to 20% by mass, preferably from 1 to 10% by mass, based on the total amount of the encapsulant for display.

 [(H) Photoradical polymerization initiator]  

The encapsulating agent for a display of the present invention may further contain a component (H) photoradical polymerization initiator (hereinafter, simply referred to as component (H)). The photoradical polymerization initiator is not particularly limited as long as it generates a radical and an acid by irradiation with ultraviolet light or visible light, and starts the chain polymerization reaction, and examples thereof include benzoin dimethyl ketal and 1 -hydroxycyclohexyl phenyl ketone, diethyl thioxanthone, diphenyl ketone, 2-ethyl hydrazine, 2-hydroxy-2-methyl propyl benzene, 2-methyl-[4-(A Thio)phenyl]-2-morpholinyl-1-propane, 2,4,6-trimethylbenzimidyldiphenylphosphine oxide, camphorquinone, 9-fluorenone, diphenyl disulfide Wait. Specifically, for example, IRGACURE ^RTM 651, 184, 2959, 127, 907, 369, 379 EG, 819, 784, 500, OXE01, OXE02, DAROCURE ^RTM 1173, LUCIRIN ^RTM TPO (all manufactured by BASF Corporation) , SEIKUOL ^RTM Z, BZ, BEE, BIP, BBI (all manufactured by Seiko Chemical Co., Ltd.).

Further, from the viewpoint of liquid crystal contamination, it is preferred to use a (meth) acrylonitrile group in the molecule. For example, 2-methylpropenyloxyethyl isocyanate and 1-[is preferably used. A reaction product of 4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one. This compound can be obtained by the method described in International Publication No. 2006/027982.

In the encapsulant for display of the present invention, when the component (H) is used, the total amount of the encapsulant for display is usually 0.001 to 3% by mass, preferably 0.002 to 2% by mass.

 [(I) Thermal Radical Polymerization Starter]  

The encapsulating agent for a display of the present invention may contain a component (I) thermal radical polymerization initiator (hereinafter also referred to simply as component (I)) to enhance the curing rate and the curability.

The thermal radical polymerization initiator is not particularly limited as long as it generates a radical by heating and starts a chain polymerization reaction, and examples thereof include an organic peroxide, an azo compound, a benzoin compound, a benzoin ether compound, and benzene. As the ethyl ketone compound, tetraphenyl-1,2-ethylene bromide, etc., tetraphenyl-1,2-ethanediol is preferably used. For example, in the case of organic peroxides, Kayamek ^RTM A, M, R, L, LH, SP-30C, Perkadox CH-50L, BC-FF, Cadox B-40ES, Perkadox 14, Trigonox ^RTM 22-70E, 23-C70, 121, 121-50E, 121-LS50E, 21-LS50E, 42, 42LS, Kayaester ^RTM P-70, TMPO-70, CND-C70, OO-50E, AN, Kayabutyl ^RTM B, Perkadox16, Kayacarbon ^RTM BIC-75, AIC-75 (made by Akzo Co., Ltd.), PERMEK ^RTM N, H, S, F, D, G, PERHEXA ^RTM H, HC, TMH, C, V, 22, MC, PERCURE ^RTM AH , AL, HB, PERBUTYL ^RTM H, C, ND, L, PERCUMYL ^RTM H, D, PEROYL ^RTM IB, IPP, PEROCTA ^RTM ND (Nippon Oil Co., Ltd.) and other commercial products.

Further, in the case of the azo compound, commercially available products such as VA-044, 086, V-070, VPE-0201, and VSP-1001 (manufactured by Wako Pure Chemical Industries, Ltd.) can be obtained.

The content of the component (I) in the total amount of the encapsulant for display is preferably 0.0001 to 10% by mass, more preferably 0.0005 to 5% by mass, particularly preferably 0.001 to 3% by mass.

 [Other ingredients]  

The encapsulant for display of the present invention may further be formulated with a (meth) acrylate resin, an epoxy resin, an organic acid or an imidazole hardening accelerator, a radical polymerization inhibitor, a pigment, a leveling agent, and an antifoaming agent, as needed. , solvents and other additives.

 [(Meth)acrylate resin]  

The (meth) acrylate resin means a (meth) acrylate monomer which is not an epoxy (meth) acrylate. The (meth) acrylate monomer may, for example, be N-propylene methoxyethyl hexahydrophthalimide, acryl morpholine, 2-hydroxypropyl (meth) acrylate, (A) 4-hydroxybutyl acrylate, cyclohexane-1,4-dimethanol mono(meth)acrylate, tetrahydrofuran methyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenyl poly Ethoxy (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, o-phenylphenol monoethoxy (meth) acrylate, o-phenyl phenol polyethoxy (meth) acrylate, p-cumyl phenoxyethyl (meth) acrylate, isodecyl (meth) acrylate, tribromophenyl oxyethyl (meth) acrylate, (methyl) Dicyclopentyl acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, 1,4-butanediol di(meth)acrylate, 1 , 6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, tricyclodecane dimethanol (meth)acrylate, bisphenol A polyethoxylate Di(meth)acrylate, bisphenol A polypropoxy di(meth)acrylate, double F polyethoxy di(meth)acrylate, ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, tris(propyleneoxyethyl)trimeric isocyanate, new Pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, tripentyltetraol hexa(meth)acrylate, Tripentaerythritol penta (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane polyethoxy tri (meth) acrylate, di-trimethylolpropane Tetraacrylate of tetra(meth)acrylate, neopentyl glycol and hydroxytrimethylacetate or diacrylate of ε-caprolactone adduct of neopentyl glycol and hydroxytrimethylacetate Monomers. Preferable examples thereof include N-propylene methoxyethyl hexahydrophthalic imide, phenoxyethyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate.

When the (meth) acrylate resin is contained, it is preferably from about 5 to 20% by mass, more preferably from 8 to 15% by mass, based on the total amount of the encapsulant for display of the present invention.

 [Epoxy resin]  

The epoxy resin is an epoxy resin other than the above component (B), preferably a bifunctional or higher epoxy resin, and examples thereof include resorcinol diepoxypropyl ether, bisphenol A epoxy resin, and double Phenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, bisphenol F novolac type epoxy Resin, alicyclic epoxy resin, aliphatic chain epoxy resin, epoxy propyl ester epoxy resin, epoxy propyl amine epoxy resin, intramethylene urea resin, trimeric isocyanate type Epoxy resin, phenol novolac type epoxy resin having a trisphenol methane skeleton, di-epoxypropyl etherate of difunctional phenol such as catechol or resorcin, and diepoxy of difunctional alcohol a propyl etherate, and such halides, hydrides, and the like. Among these, from the viewpoint of liquid crystal contamination, a bisphenol A type epoxy resin and resorcinol diepoxypropyl ether are preferable.

When the epoxy resin is contained, it is preferably from about 5 to 20% by mass, more preferably from 8 to 15% by mass, based on the total amount of the encapsulant for display of the present invention.

 [hardening accelerator]  

The hardening accelerator may, for example, be an organic acid, an imidazole or the like.

The organic acid may, for example, be an organic carboxylic acid or an organic phosphoric acid, and an organic carboxylic acid is preferred. Specific examples thereof include aromatic carboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, diphenyl ketone tetracarboxylic acid, and furan dicarboxylic acid, succinic acid, and adipic acid. , dodecanedioic acid, sebacic acid, thiodipropionic acid, cyclohexanedicarboxylic acid, tris(2-carboxymethyl)trimeric isocyanate, tris(2-carboxyethyl)trimeric isocyanate, three (2) -Carboxypropyl)trimeric isocyanate, bis(2-carboxyethyl)trimeric isocyanate, and the like.

Further, examples of the imidazole compound include 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenyl-4-methylimidazole, and 1-benzylmethyl group. -2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2 -undecyl imidazole, 2,4-diamino-6 (2'-methylimidazolium (1')) ethyl-all three 2,4-Diamino-6(2'-undecylimidazolium (1')) ethyl-all three 2,4-Diamino-6(2'-ethyl-4-methylimidazolium (1'))ethyl-all three 2,4-Diamino-6(2'-methylimidazolium(1'))ethyl-all three ‧ Trimeric isocyanate adduct, 2:3 adduct of 2-methylimidazolium trimeric isocyanate, 2-phenylimidazole trimer isocyanate adduct, 2-phenyl-3,5 - Dihydroxymethylimidazole, 2-phenyl-4-hydroxymethyl-5-methylimidazole, 1-cyanoethyl-2-phenyl-3,5-dicyanoethoxymethylimidazole, and the like.

In the sealing agent for a display of the present invention, when a curing accelerator is used, the total amount of the encapsulating agent for a display is usually 0.1 to 10% by mass, preferably 1 to 5% by mass.

 [Radical Polymerization Inhibitor]  

The radical polymerization inhibitor is not particularly limited as long as it reacts with a radical generated by a photoradical polymerization initiator or a thermal radical polymerization initiator to prevent polymerization, and an anthracene or piperidine can be used. A system, a hindered phenol system, a nitroso group, and the like. Specific examples thereof include naphthoquinone, 2-hydroxynaphthoquinone, 2-methylnaphthoquinone, 2-methoxynaphthoquinone, 2,2,6,6-tetramethylpiperidin-1-oxyl, 2,2,6,6-tetramethyl-4-hydroxypiperidin-1-yloxy, 2,2,6,6-tetramethyl-4-methoxypiperidin-1-yl, 2, 2,6,6-tetramethyl-4-phenoxypiperidin-1-yloxy, hydroquinone, 2-methylhydroquinone, 2-methoxyhydroquinone, p-benzoquinone, butylated hydroxyl group Anisole, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl cresol, β-(3,5-di-tertiary butyl-4-hydroxyphenyl) ) stearyl propionate, 2,2'-methylenebis(4-ethyl-6-tertiary butylphenol), 4,4'-thiobis(3-methyl-6-tertiary Phenol), 4,4'-butylene bis(3-methyl-6-tertiary butylphenol), 3,9-bis[1,1-dimethyl-2-[β-(3-three Grade butyl-4-hydroxy-5-methylphenyl)propanoxy]ethyl], 2,4,8,10-tetraoxaspiro[5,5]undecane, tetra-[Asia Methyl-3-(3',5'-di-tertiary butyl-4'-hydroxyphenylpropionate)]methane, 1,3,5-tris(3',5'-di-three Butyl-4'-hydroxybenzyl)-all three -2,4,6-(1H,3H,5H)trione, p-methoxyphenol, 4-methoxy-1-naphthol, dibenzothiazide An aluminum salt of N-nitrosophenylhydroxylamine, trade name: ADK STAB LA-81, trade name: ADK STAB LA-82 (made by Adeka Co., Ltd.), etc., but it is not limited to these. Among these, a naphthoquinone-based, hydroquinone-based, nitroso-based, piperidine-based radical polymerization inhibitor is preferred, and more preferably naphthoquinone, 2-hydroxynaphthoquinone, hydroquinone, 2,6- Di-tertiary butyl-p-cresol, POLYSTOP 7300P (manufactured by Berton Co., Ltd.), preferably POLYSTOP 7300P (manufactured by Bodson Co., Ltd.).

In the total amount of the encapsulating agent for a display of the present invention, the content of the radical polymerization inhibitor is preferably 0.0001 to 1% by mass, more preferably 0.001 to 0.5% by mass, particularly preferably 0.01 to 0.2% by mass.

An example of the method of producing the encapsulant for a display of the present invention is as follows. First, the component (A) and optionally the component (B) and the component (H) are dissolved by heating. Then, after cooling to room temperature, component (C), component (D), component (E), component (F), component (G), component (I), antifoaming agent, and leveling agent are added as needed. The solvent or the like is uniformly mixed by a well-known mixing device (for example, a three-roll mill, a sand mill, a ball mill, etc.) and filtered by a metal mesh, whereby the encapsulant for display of the present invention can be produced.

The encapsulant for display of the present invention is very useful as an encapsulant for electronic parts and an adhesive for electronic parts. Examples of the encapsulant and the adhesive for the electronic component include, for example, an adhesive for a flexible printed wiring board, an adhesive for TAB, an adhesive for a semiconductor, and an adhesive for various displays, but are not limited thereto.

Further, the encapsulant for display of the present invention is very useful as an adhesive for a liquid crystal display unit, particularly a liquid crystal sealing agent. The liquid crystal display unit when the encapsulant for display of the present invention is used as the liquid crystal sealing agent is exemplified below.

The liquid crystal display unit manufactured by using the adhesive for liquid crystal display unit of the present invention is such that one of the predetermined electrodes is formed on the substrate, and the substrate is disposed opposite to each other at a predetermined interval, and the liquid crystal sealing agent of the present invention is surrounded. Sealed, and the liquid crystal is sealed in the gap. The type of the liquid crystal to be enclosed is not particularly limited. Here, the substrate means a substrate including a combination of at least one of glass, quartz, plastic, germanium, and the like having light transmissivity. In the liquid crystal sealing agent of the present invention, a spacer such as a glass fiber (gap control material) is added to the liquid crystal sealing agent of the present invention, and the liquid crystal sealing agent is applied to the liquid crystal sealing agent by using a dispenser or a screen printing apparatus. After one of the pair of substrates, temporary hardening is performed at 80 to 120 ° C as needed. Thereafter, the liquid crystal was dropped on the inside of the crucible of the liquid crystal sealing agent, and another glass substrate was laminated in a vacuum to generate a gap. After the gap is formed, the film is cured at 90 to 130 ° C for 30 minutes to 2 hours, whereby the liquid crystal display unit of the present invention can be obtained. Further, when it is used as a photothermal type, the liquid crystal sealing agent portion is irradiated with ultraviolet rays by an ultraviolet ray irradiator to cure the light. The amount of ultraviolet irradiation is preferably from 500 to 6,000 mJ/cm ² , more preferably from 1,000 to 4,000 mJ/cm ² . Thereafter, the film is cured at 90 to 130 ° C for 30 minutes to 2 hours as needed, whereby the liquid crystal display unit of the present invention can be obtained. The liquid crystal display unit of the present invention thus obtained has no display failure due to liquid crystal contamination, and is excellent in adhesion and moisture resistance reliability. The spacer may, for example, be glass fiber, cerium oxide beads, polymer beads or the like. The diameter thereof varies depending on the purpose, but is usually 2 to 8 μm, preferably 4 to 7 μm. The amount of use is usually from 0.1 to 4 parts by mass, preferably from 0.5 to 2 parts by mass, more preferably from 0.9 to 1.5 parts by mass, per 100 parts by mass of the liquid crystal sealing agent of the present invention.

Since the encapsulant for display of the present invention has both flexibility and low moisture permeability, it is very suitable for use as an adhesive for use in a field which is used for a flexible substrate or the like and which requires moisture resistance reliability. For example, a liquid crystal sealing agent, an encapsulant for organic EL, and an adhesive for a touch panel.

The flexibility of the encapsulant for display of the present invention can be expressed by the modulus of elasticity, the elongation at break, and the stress at break at a room temperature (22 ° C) of a cured film having a thickness of 100 μm using a TENSILON universal testing machine. The modulus of elasticity is preferably 1000 MPa or less, more preferably 600 MPa or less. The elongation at break is preferably 30% GL or more, and more preferably 50% GL or more. The stress at the breaking point is preferably 50 MPa or less, more preferably 30 MPa or less.

The moisture permeability of the encapsulating agent for a display of the present invention can be expressed by a moisture permeability of a cured film having a thickness of 100 μm at 60 ° C and 90% using a moisture permeability measuring machine. The moisture permeability is 160g/m ² . 24 hours is better, more preferably 140g/m ² . 24 hours.

 [Examples]  

Hereinafter, the present invention will be described in more detail by way of examples, but the invention is not limited to the examples. In addition, unless otherwise stated, "parts" and "%" in this document are quality standards.

 [Synthesis Example 1:1, Synthesis of 2-bis(trimethyldecyloxy)-1,1,2,2-tetraphenylethane]  

100 parts (0.28 mol) of commercially available tetraphenyl-1,2-ethanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 350 parts of dimethylformaldehyde. To this was added 32 parts (0.4 mol) of pyridine as a basic catalyst, and 150 parts (0.58 mol) of BSTFA (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silylating agent, and the temperature was raised to 70 ° C, and stirred for 2 hours. . The resulting reaction solution was cooled, and 200 parts of water was added while stirring to precipitate a product while deactivating the unreacted decylating agent. The precipitated product was separated by filtration and washed thoroughly with water. Next, the obtained product was dissolved in acetone, and recrystallized by adding water to carry out purification. 105.6 parts of a 1,2-bis(trimethyldecyloxy)-1,1,2,2-tetraphenylethane of the object was obtained (yield: 88.3%).

 [Examples 1 to 3, Comparative Examples 1, 2]  

The component (A), the component (B), and the component (H) were dissolved by heating at 90 ° C according to the ratio shown in the following Table 1, and then cooled to room temperature, and the component (C), the component (D), and the component (E) were added. The component (F), the component (G), and the component (I) were stirred, dispersed in a three-roll mill, and filtered through a metal mesh (635 mesh) to prepare Examples 1 to 3 and Comparative Example 1. 2.

 [compatibility]  

With respect to the liquid crystal sealing agents produced in the examples and the comparative examples, the compatibility was evaluated at room temperature (22 ° C) in the following manner: ○ was compatible, Δ was slightly cloudy, × was white turbid or separated. The results are shown in Table 1.

Further, the compatibility of Comparative Example 2 was ×, that is, the liquid crystal sealing agent showed phase separation, and therefore the physical property evaluation described below was not carried out.

 [Elastic modulus, elongation at break point, stress at break point]  

The liquid crystal sealing agent produced in the examples and the comparative examples was laminated on a polyethylene terephthalate (PET) film to form a film having a thickness of 100 μm, and was irradiated with a metal halide lamp (manufactured by USHIO Electric Co., Ltd.). After hardening by ultraviolet rays of 3000 mJ/cm ² (100 mW/cm ² , 30 seconds), it was put into an oven at 120 ° C for 40 minutes to be hardened. Thereafter, the PET film was peeled off and the sealant cured film was cut into a dumbbell-shaped test piece (having an overall length of 75 mm, an overall width of 10 mm, a narrow parallel portion having a length of 50 mm, and a width of 5 mm) as a sample piece. The obtained test piece was subjected to a tensile test at a test speed of 5 mm/min at a room temperature (22 ° C) using a TENSILON universal testing machine (RTG-1210, manufactured by A&D Co., Ltd.), and stretched within a proportional limit. The results of stress and strain calculate the elastic modulus. The results of the elastic modulus, the elongation at break, and the stress at the breaking point are shown in Table 1.

 [transmotive humidity]  

The liquid crystal sealing agent produced in the examples and the comparative examples was laminated on a polyethylene terephthalate (PET) film to form a film having a thickness of 100 μm, and was irradiated with a metal halide lamp (manufactured by USHIO Electric Co., Ltd.). After hardening by ultraviolet rays of 3000 mJ/cm ² (100 mW/cm ² , 30 seconds), it was put into an oven at 120 ° C for 40 minutes to be hardened. Thereafter, the PET film was peeled off as a sample. The sample was measured for moisture permeability at 60 ° C and 90% by a moisture permeability measuring machine (manufactured by Lessy Co., Ltd.: L80-5000). The results are shown in Table 1.

A-1: Bismaleimide compound (BMI-1500 Alfa Aesar)

X-1: bisphenol A type epoxy acrylate (synthesized by the method described in JP-A-2016-24243)

B-1: epoxidized polybutadiene (JP-100 Japan Soda Co., Ltd.)

C-1: neopentyl alcohol tetrakis(3-mercaptobutyrate) (Karenz PE-1 Showa Denko Co., Ltd.)

D-1: Polymethacrylate organic fine particles (manufactured by AICA Industrial Co., Ltd.: F-351S)

E-1: spherical cerium oxide (manufactured by Tokuyama Co., Ltd.: SANSIL SSP-07M)

F-1: 3-glycidoxypropyltrimethoxydecane (manufactured by JNC Co., Ltd.: Sila-Ace S-510)

G-1: 癸二醯肼 (manufactured by Otsuka Chemical Co., Ltd.: SDH)

G-2: Tris(2-mercaptocarbonylethyl)trimeric isocyanate finely pulverized product (manufactured by Japan Finechem Co., Ltd.: HCIC, finely pulverized into 1.5 μm by a jet mill)

H-1: 2,4,6-trimethylbenzimidyldiphenylphosphine oxide (manufactured by BASF Corporation: LR-8953)

H-2: 2,2-isocyanatoethyl methacrylate and 2-hydroxy-1-[4-(2-hydroxyethoxy)-phenyl]-2-methylpropan-1-one Reaction product (manufactured by Nippon Kayaku Co., Ltd.: RPI-4)

I-1:1,2-bis(trimethyldecyloxy)-1,1,2,2-tetraphenylethane (synthesis example 1 was finely pulverized into a mean 1.9 μm by a jet mill)

J-1: nitroso piperidine derivative (Bodong Co., Ltd.: POLYSTOP 7300P)

J-2: Tris(3-carboxyethyl)trimeric isocyanate (manufactured by Shikoku Chemical Industry Co., Ltd.: CIC acid, finely pulverized by a jet mill to an average particle diameter of 1.5 μm)

J-3: hydrogenated polybutadiene acrylate (made by Japan Soda Co., Ltd.: TEAI-1000)

J-4: Bisphenol A type epoxy resin (manufactured by Nippon Kayaku Co., Ltd.: RE-310)

As shown in Table 1, the encapsulants for displays of Examples 1 to 3 have high flexibility and a low moisture permeability. Therefore, it has been confirmed that the encapsulant for display of the present invention has excellent characteristics as an adhesive for use in a flexible substrate or the like.

The encapsulant for display of the present invention can be used as an adhesive for electronic parts, particularly an encapsulant for displays, since it can achieve both flexibility and low moisture permeability.

Claims (16)

 An encapsulating agent for a display comprising a maleimide compound having a component (A) having a hydrocarbon group of from C10 to C50 in the molecule, and a content of the epoxy (meth) acrylate compound of less than 5% by mass.    The encapsulating agent for a display according to claim 1 further contains a component (B) having a compound having an epoxy group in the molecule and having a number average molecular weight of 500 to 10,000.   The encapsulating agent for a display according to the first or second aspect of the invention, wherein the component (A) is a maleic imine compound represented by the following formula (1); In the formula (1), R ¹ represents a divalent crosslinking group having a hydrocarbon group of C10 to C50 and the like. The encapsulating agent for a display according to the third aspect of the invention, wherein in the formula (1), R ¹ is a heterocyclic group.  The encapsulating agent for a display according to any one of claims 1 to 4, wherein the component (B) is a polybutadiene or a polyisoprene compound.    The encapsulating agent for a display according to any one of claims 1 to 5, wherein the component (B) is a compound further having a reactive double bond in the molecule.    The encapsulating agent for a display according to any one of claims 1 to 6, further comprising a component (C) thiol compound.    The encapsulant for display according to claim 7, wherein the component (C) is a polyfunctional thiol compound.    The encapsulant for display according to any one of claims 1 to 8, further comprising the component (D) organic filler.    The encapsulating agent for a display according to claim 9, wherein the component (D) is selected from the group consisting of urethane microparticles, acrylic microparticles, styrene microparticles, styrene olefin microparticles, and polyfluorene microparticles. One or more organic fillers in the group.    The encapsulating agent for a display according to any one of claims 1 to 10, further comprising the component (E) inorganic filler.    The encapsulating agent for a display according to any one of claims 1 to 11, further comprising a component (F) decane coupling agent.    The encapsulating agent for a display according to any one of claims 1 to 12, further comprising a component (G) thermosetting agent.    The encapsulating agent for a display according to any one of claims 1 to 13, further comprising a component (H) photoradical polymerization initiator.    The encapsulating agent for a display according to any one of claims 1 to 14, further comprising a component (I) thermal radical polymerization initiator.    A liquid crystal display unit is obtained by using the encapsulant for display according to any one of claims 1 to 15.