TW201927990A - Sealing agent for display - Google Patents

Abstract

The present invention relates to a sealing agent for display which can be applied to flexible displays and curved displays. More specifically, the present invention relates to a sealing agent for display containing a compound having a specific structure in the molecule. The sealing agent for display is capable of achieving both flexibility and low moisture permeability, and is useful as a sealing agent for a display which is required to have adhesiveness with an organic film, flexible displays, and curved displays. A sealing agent for display according to the present invention contains component (A): a curable compound having three or more bisphenol skeletons in the molecule and three or more reactive functional groups.

Description

Display Encapsulant

The present invention relates to a display encapsulant that can be applied to flexible displays and curved displays. More specifically, the present invention relates to an encapsulant for a display that satisfies a specific relationship between glass transition temperature and elastic modulus. Since this display encapsulant can achieve both flexibility and low moisture permeability, it is particularly suitable as an encapsulant for flexible displays and curved displays.

In addition, since the encapsulant with rich flexibility as in the present invention has excellent adhesion strength to an adhesive, it is also useful in applications requiring high adhesion strength.

Examples of the display encapsulant include a sealant for a liquid crystal display, an encapsulant for an organic EL display, and an adhesive for a touch panel. These materials have a common point in that they are required to have excellent hardenability, and at the same time have the characteristics of low exhaust gas and no damage to the display element.

In addition, a curved display or a flexible display has recently been developed and commercialized. The substrate used in such a display is a flexible one such as plastic instead of a rigid one such as glass (Patent Document 1).

Due to such a background, the display encapsulant is required to follow a curve of the substrate, that is, a property that is "soft even after curing".

Moreover, an encapsulant excellent in flexibility is also advantageous in terms of adhesion strength. For example, it can reduce peeling caused by punching or damage to implement materials. From this viewpoint, the requirement for imparting flexibility to the encapsulant is also increased.

On the other hand, in order to improve the flexibility of the cured product, it is effective to reduce the crosslinking density of the cured product. However, if the crosslinking density is lowered, the moisture permeability is generally deteriorated. It is believed that this is because moisture can invade from loose parts of the tissue. Therefore, in order to ensure low moisture permeability, it is necessary to achieve the opposite characteristics of "improving flexibility without reducing the crosslinking density" or "reducing the crosslinking density without deteriorating the moisture permeability".

Conventionally, from the viewpoint of improving the bonding strength, development of an adhesive for display elements having flexibility has been performed (Patent Document 2). However, there has not yet been realized a device that has sufficient performance for the above-mentioned flexible substrates.

[Prior technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2012-238005

[Patent Document 2] Japanese Patent Laid-Open No. 2016-24240

The present invention relates to flexible displays and bending applications. A display encapsulant for a shaped display. More specifically, it relates to a sealing agent for a display using a compound having three or more reactive functional groups and specific physical properties. This display encapsulant is suitable as a display encapsulant because it can achieve both flexibility and low moisture permeability.

As a result of intensive research, the present inventors have found that a sealing agent for a display containing a compound having three or more reactive functional groups and specific physical properties is excellent in flexibility and low moisture permeability, and completed the present invention.

The "(meth) acrylic acid" in this specification means "acrylic acid" and / or "methacrylic acid".

That is, the present invention relates to the following items [1] to [14].

[1] An encapsulant for a display, which contains a component (A), which is a hardening compound having three or more bisphenol skeletons and three or more reactive functional groups in a molecule.

[2] The encapsulant for a display according to the above item [1], wherein two or more of the bisphenol skeletons of the component (A) are bisphenol A skeletons.

[3] The encapsulant for a display according to the above item [1] or [2], wherein the weight average molecular weight of the component (A) is 1,000 or more.

[4] The encapsulant for a display according to any one of the items [1] to [3], wherein two or more of the reactive functional groups of the component (A) are (meth) acrylfluorenyl groups .

[5] The encapsulant for a display according to any one of the foregoing items [1] to [4], It further contains a component (B), which is a curable compound.

[6] The encapsulant for a display according to the item [5], wherein the component (B) is a component (B-1), and the component (B-1) is a (meth) acrylic compound.

[7] The encapsulant for a display according to the above item [5], wherein the component (B) is a mixture of components (B-1) and (B-2), and the component (B-1) is (methyl) ) An acrylic compound, and the component (B-2) is an epoxy compound.

[8] The encapsulant for a display according to any one of the items [1] to [7], further comprising a component (C), which is an organic filler.

[9] The encapsulant for a display according to any one of the items [1] to [8], further comprising a component (D), which is an inorganic filler.

[10] The encapsulant for a display according to any one of the items [1] to [9], further comprising a component (E), which is a silane coupling agent.

[11] The encapsulant for a display according to any one of the items [1] to [10], further comprising a component (F), which is a thermosetting agent.

[12] The encapsulant for a display according to any one of the items [1] to [11], further comprising a component (G), which is a photoradical polymerization initiator.

[13] The encapsulant for a display according to any one of the items [1] to [12], further comprising a component (H), which is a thermal radical polymerization initiator.

[14] A liquid crystal display, which is sealed with the display encapsulant according to any one of the above items [1] to [13].

The display sealing agent of the present invention is suitable as a display sealing agent because it can achieve both flexibility and low moisture permeability.

[(A) A hardening compound having three or more bisphenol skeletons and three or more reactive functional groups in the molecule]

The encapsulant for a display of the present invention contains (A) a hardening compound having three or more bisphenol skeletons and three or more reactive functional groups in a molecule (hereinafter also simply referred to as "component (A)"). As far as this compound is concerned, it has a certain degree of flexibility. In order to achieve a high cross-link density using a large number of functional groups even after the hardening reaction, and in order to obtain the effect of the present invention, this compound is necessary. In addition, a compound having this characteristic can obtain a sufficient effect even if it is added in a small amount.

The component (A) has three or more bisphenol skeletons. The bisphenol skeleton refers to a skeleton represented by the following formula (1), and a bisphenol A skeleton is preferred. Therefore, in the case of the component (A), it is also preferable that two or more of the three or more bisphenol skeletons are bisphenol A skeletons.

(In formula (1), R represents CH ₂ , CH (CH ₃ ), C (CH ₃ ) ₂ , S, O, SO _2. )

The component (A) has three or more reactive functional groups. The reactive functional group means a reactive double bond (vinyl, allyl, (meth) acryl group, etc.), a cyclic ether group (epoxy group, glycidyl group, oxetanyl group, etc.) , Carboxyl, hydroxyl, amine, hydrazino, thiol, and the like. Among them, The case of a reactive double bond is preferred, and the case where two or more of the three or more reactive functional groups are reactive double bonds is more preferred. Furthermore, a case where two or more are (meth) acrylfluorenyl groups is particularly preferable, and a case where three or more are (meth) acrylfluorenyl groups are most preferable. The number of reactive functional groups is not particularly limited if it is three or more, but it is preferably a case of 3 to 6, and a case of 3 or 4 is particularly preferred.

From the viewpoint of flexibility and adhesion, the component (A) preferably has an ester group or a hydroxyl group in the molecule. When it has an ester group, it is preferable to have three or more ester groups, and it is more preferable to have six or more. When it has a hydroxyl group, it is preferable to have three or more hydroxyl groups.

The component (A) is preferably a weight average molecular weight of 1,000 or more, and more preferably 1200 or more. The upper limit is preferably 5,000 or less, and more preferably 3,000 or less. When the weight average molecular weight is in the above range, it contributes to the flexibility of the cured product, and specifically contributes to a low elastic modulus and a high elongation at break. In addition, the display encapsulant is adjusted to a suitable viscosity range.

Moreover, the reactive group equivalent is preferably 300 to 700, and more preferably 400 to 600.

In addition, in the total display encapsulant, the preferred content of the component (A) is usually 5 to 50% by mass, more preferably 5 to 30% by mass, and even more preferably 10 to 20% by mass.

[(B) hardening compound]

The sealant for a display of the present invention contains a curable compound as a component (B) (hereinafter also simply referred to as "component (B)").

If the component (B) is a compound hardened by light, heat, etc., it is not special. Restrictions are preferred in the case of (B-1) (meth) acrylic compound (hereinafter also referred to as "component (B-1)").

The "(meth) acrylic acid" herein means "acrylic acid" and / or "methacrylic acid (the same shall apply hereinafter). Examples of the component (B-1) include (meth) acrylate compounds, (meth) ) Acrylic epoxy ester compounds and the like.

[(B-1) (meth) acrylic compound]

Specific examples of the (meth) acrylate compound include N-acryloxyethylhexahydrophthalimide, allylmorpholine, 2-hydroxypropyl (meth) acrylate, ( 4-hydroxybutyl methacrylate, cyclohexane-1,4-dimethanol mono (meth) acrylate, tetrahydrofuran methyl (meth) acrylate, phenoxyethyl (meth) acrylate, ( Phenyl polyethoxylate (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, o-phenylphenol monoethoxy (meth) acrylate, o-phenylphenol poly Ethoxy (meth) acrylate, p-cumylphenoxyethyl (meth) acrylate, isobornyl (meth) acrylate, tribromophenoxyethyl (meth) acrylate, ( Dicyclopentylethyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyl (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, tricyclodecanedimethanol (meth) acrylate, bisphenol A polyethoxy Di (meth) acrylate, bisphenol A polypropoxy di (meth) acrylate, bisphenol F poly Oxydi (meth) acrylate, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, ginsyl (propyleneoxyethyl) trimeric isocyanate, neopentyl tetraol Tetra (meth) acrylate, dinepentaerythritol hexa (meth) acrylate, dinepentaerythritol penta (meth) acrylate, trinepentaerythritol hexa (meth) acrylate, trineopenta four Alcohol penta (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane polyethoxytri (meth) acrylate, bis (trimethylolpropane) tetrakis (methyl) Monomers such as acrylic acid esters, ester diacrylates of neopentyl glycol and hydroxytrimethylacetate, or diacrylates of ε-caprolactone adducts of esters of neopentyl glycol and hydroxytrimethylacetate class. Preferable examples include N-propylene ethoxyethylhexahydrophthalimide, phenoxyethyl (meth) acrylate, and dicyclopentenyl ethyl (meth) acrylate.

The (meth) acrylic epoxy ester compound can be obtained by a known method by the reaction of an epoxy compound and (meth) acrylic acid. Although the epoxy compound used as a raw material is not particularly limited, it is preferably a bifunctional or more functional epoxy compound, and examples thereof include resorcinol diglycidyl ether, bisphenol A type epoxy compound, and bisphenol F type Epoxy compounds, bisphenol S epoxy compounds, phenol novolac epoxy compounds, cresol novolac epoxy compounds, bisphenol A novolac epoxy compounds, bisphenol F novolac epoxy compounds, grease Cyclic epoxy compound, aliphatic chain epoxy compound, glycidyl ester type epoxy compound, glycidylamine type epoxy compound, hydantoin type epoxy compound, trimeric isocyanate type epoxy compound, having triphenol Phenolic novolac epoxy compounds of methane skeleton, other diglycidyl ethers of bifunctional phenols such as catechol, resorcinol, diglycidyl ethers of difunctional alcohols, and the like Halides, hydrides, etc. Among these compounds, a bisphenol A type epoxy compound or resorcinol diglycidyl ether is preferred from the viewpoint of liquid crystal contamination. Further, the ratio between the epoxy group and the (meth) acrylfluorenyl group is not limited, and can be appropriately selected from the viewpoint of engineering applicability. It is also suitable to use a part of epoxy group Acrylated partially epoxy (meth) acrylate. The proportion of acrylated at this time is preferably about 30 to 70%.

The component (B-1) may be used alone, or two or more kinds may be mixed. When the component (B-1) is used in the display sealing agent of the present invention, the display sealing agent is usually 5 to 50% by mass, and preferably 5 to 30% by mass.

[(B-2) epoxy compound]

In the aspect of the present invention, it is preferable that the component (B) further contains (B-2) an epoxy compound (hereinafter also simply referred to as "component (B-2)").

Although the epoxy compound is not particularly limited, it is preferably an epoxy compound having two or more functions, and examples thereof include resorcinol diglycidyl ether, bisphenol A type epoxy resin, bisphenol F type epoxy resin, Bisphenol S epoxy resin, phenol novolac epoxy resin, cresol novolac epoxy resin, bisphenol A novolac epoxy resin, bisphenol F novolac epoxy resin, alicyclic epoxy Resin, aliphatic chain epoxy resin, glycidyl ester epoxy resin, glycidylamine epoxy resin, hydantoin type epoxy resin, trimeric isocyanate type epoxy resin, phenol having a triphenol methane skeleton Novolac epoxy resin, other bifunctional diglycidyl ethers such as catechol and resorcinol, difunctional glycidyl ethers of difunctional alcohols, and the halides and hydrides of these Wait. From the viewpoint of liquid crystal contamination, among these compounds, bisphenol A epoxy resin or resorcinol diglycidyl ether is preferred.

The component (B-2) may be used alone, or two or more kinds may be mixed. In the display sealing agent of the present invention, when the component (B-2) is used, it is usually 5 to 50% by mass of the total display sealing agent, and 5 to 30% by mass is good.

Moreover, in the display sealing agent of this invention, the compounding quantity of a component (B) is 10-80 mass% normally in the total amount of the display sealing agent, Preferably it is 20-70 mass%. The compounding amount when the component (B-1) and the component (B-2) are mixed and used is also the same.

[(C) Organic filler]

The display sealing agent of the present invention may contain an organic filler as a component (C) (hereinafter also simply referred to as "component (C)"). Examples of the organic filler include amine ester fine particles, acrylic fine particles, styrene fine particles, styrene olefin fine particles, and polysiloxane fine particles. Further, the polysiloxane particles are preferably KMP-594, KMP-597, KMP-598 (made by Shin-Etsu Chemical Industry), Trefil ^RTM E-5500, 9701, EP-2001 (made by Dow Corning Toray); The amine ester particles are preferably JB-800T, HB-800BK (Gensang Industrial Co., Ltd.); the styrene particles are preferably Rabalon ^RTM T320C, T331C, SJ4400, SJ5400, SJ6400, SJ4300C, SJ5300C, SJ6300C (manufactured by Mitsubishi Chemical); benzene; The ethylene olefin fine particles are preferably Septon ^RTM SEPS2004 and SEPS2063.

These organic fillers may be used singly or in combination of two or more kinds. In addition, a core shell structure can be formed using two or more types. Among these fine particles, acrylic fine particles and polysiloxane fine particles are preferred.

When the above-mentioned acrylic fine particles are used, an acrylic rubber having a core-shell structure formed of two types of acrylic rubber is preferable, and a core layer is n-butyl acrylate and a shell layer is methyl methacrylate. This has been made into Zefiac ^RTM F-351 and sold by AICA Industrial Co., Ltd.

Examples of the polysiloxane fine particles include organic polysiloxane crosslinked powders, linear dimethyl polysiloxane crosslinked powders, and the like. Further, examples of the composite silicone rubber include a silicone rubber (for example, a polyorganosilsesquioxane resin) coated on the surface of the silicone rubber. Among these fine particles, is a silicone rubber coated with a linear dimethylpolysiloxane crosslinked powder or a composite silicone rubber coated with a linear dimethylpolysiloxane crosslinked powder by a silicone resin. Microparticles are particularly preferred. These fine particles may be used alone or in combination of two or more kinds. In addition, the shape of the rubber powder is preferably a spherical shape with less viscosity increase after the addition. When the component (C) is used in the display sealing agent of the present invention, the component (C) is usually 5 to 50% by mass, and preferably 5 to 40% by mass in the total amount of the display sealing agent.

[(D) Inorganic filler]

The sealing agent for a display of the present invention may contain an inorganic filler as a component (D) (hereinafter also simply referred to as a component (D)). Examples of the inorganic filler contained in the present invention include: silicon oxide, silicon carbide, silicon nitride, boron nitride, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, Aluminum oxide, magnesium oxide, zirconia, aluminum hydroxide, magnesium hydroxide, calcium silicate, aluminum silicate, lithium aluminum silicate, zirconium silicate, barium titanate, glass fiber, carbon fiber, molybdenum disulfide, asbestos, etc .; Preferred examples include fused silica, crystalline silica, silicon nitride, boron nitride, calcium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, aluminum hydroxide, calcium silicate, silicon Acid aluminum; silicon oxide, aluminum oxide, and talc are preferred. These inorganic fillers may be used by mixing two or more kinds.

If the average particle diameter of the inorganic filler is too large, it will produce narrow gaps (narrow gap) in a liquid crystal display unit may cause disadvantages such as poor formation of a gap when the upper and lower glass substrates are bonded. Therefore, 2,000 nm or less is preferred, 1,000 nm is preferred, and 300 nm or less . The preferable lower limit is about 10 nm, and more preferably about 100 nm. The particle size can be measured by a laser diffraction / scattering type particle size distribution measuring device (dry type) (manufactured by Seishin Corporation; LMS-30).

When an inorganic filler is used in the display sealing agent of the present invention, the inorganic filler is usually 5 to 50% by mass and preferably 5 to 40% by mass in the total amount of the display sealing agent. When the content of the inorganic filler is less than 5% by mass, the adhesive strength to the glass substrate is reduced, and the moisture resistance reliability is also deteriorated. Therefore, the adhesive strength after moisture absorption may be greatly reduced. In addition, when the content of the inorganic filler is more than 50% by mass, the content of the filler is too large, and it may become difficult to crack and the slits of the liquid crystal cell may not be formed.

[(E) Silane coupling agent]

The sealing agent for a display of the present invention may contain a silane coupling agent as a component (E) (hereinafter also simply referred to as "component (E)") to improve the adhesion strength and moisture resistance.

Examples of the component (E) include 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, and 3-glycidyloxypropylmethyldiethoxy Silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3 -Aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3- Thiol propyltrimethoxysilane, vinyltrimethoxysilane, N- (2- (ethyl Alkenyl benzylamino) ethyl) 3-aminopropyltrimethoxysilane chlorate, 3-methacryloxypropyltrimethoxysilane, 3-chloropropylmethyldimethoxy Silyl, 3-chloropropyltrimethoxysilane, and the like. These silane coupling agents have been sold as the KBM series, KBE series, and the like by Shin-Etsu Chemical Industry Co., Ltd. and the like, and thus can be easily obtained from the market. When the component (E) is used in the display sealing agent of the present invention, the component (E) is preferably 0.05 to 3% by mass based on the total amount of the display sealing agent.

[(F) Thermal hardener]

The display sealing agent of the present invention may include a thermosetting agent as a component (F) (hereinafter also simply referred to as "component (F)") to improve the reactivity.

Examples of the component (F) include, but are not limited to, compounds having a carboxyl group bonded to an aromatic ring in the molecule, polyamines, polyphenols, organic acid hydrazine compounds, and the like. Examples include dihydrazine terephthalate, dihydrazine isophthalate, dihydrazine isophthalate, 2,6-naphthoate dihydrazine, 2,6-pyridine dihydrazine, 1, 2, 2, 4-Benzyltrimethylhydrazine, 1,4,5,8-naphthoic acid tetramethylhydrazine, pyromellitic acid tetramethylhydrazine and the like. Moreover, in the case of an aliphatic hydrazine compound, for example, formamidine, acetazine, hydrazine propionate, dihydrazine oxalate, dihydrazine malonate, dihydrazine succinate, and glutaric acid dihydrate Hydrazine, dihydrazine adipate, dihydrazide pimelate, dihydrazide sebacate, 1,4-cyclohexanedihydrazide, dihydrazide tartrate, dihydrazine malate, imine diacetic acid Dihydrazine, N, N'-hexamethylenebishemicarbazide, trimethylhydrazine citrate, trimethylhydrazine nitroacetate, trimethylhydrazine of cyclohexanetricarboxylic acid, 1,3-bis (hydrazinocarbethyl (I)) 5-Hydroxycarbamide skeleton such as isopropylhydantoin, preferably one having a valproic acid hamtolide skeleton (a skeleton in which the carbon atom of the hydantoin ring is substituted with isopropyl group) Hydrazine compounds, ginseng (1-hydrazinocarbonylmethyl) trimeric isocyanate, ginseng (2-hydrazinocarbonylethyl) trimeric isocyanate, ginseng (1-hydrazinocarbonylethyl) trimeric isocyanate, ginseng (3-hydrazinocarbonylpropyl) ) Trimeric isocyanate, bis (2-hydrazinocarbonylethyl) trimeric isocyanate, and the like. In terms of the balance between curing reactivity and latentity, diisohydrazine isophthalate, dihydrazine malonate, dihydrazine adipate, and ginseng (1-hydrazinocarbonylmethyl) trimer isocyanate are preferred. Ginseng (1-hydrazinocarbonylethyl) trimer isocyanate, ginseng (2-hydrazinocarbonylethyl) trimer isocyanate, ginseng (3-hydrazinocarbonylpropyl) trimer isocyanate, particularly preferably ginseng (2- Hydrazinocarbonylethyl) trimeric isocyanate.

The component (F) is preferably a compound having a carboxyl group bonded to an aromatic ring in the molecule, and examples thereof include 4-hydroxybenzoic acid, thiosalicylic acid, terephthalic acid, and 2,6-dihydroxy. Citrazinic acid, 4-aminobenzoic acid, 4- (aminomethyl) benzoic acid, 2-mercaptonicotinic acid.

The component (F) may be used alone, or two or more kinds may be mixed. When the component (F) is used in the display sealing agent of the present invention, the component (F) is usually 0.1 to 10% by mass, and preferably 0.1 to 5% by mass, based on the total amount of the display sealing agent.

A hardening catalyst can be added to the display sealing agent of the present invention to improve the reactivity. Examples of the curing catalyst include amines and imidazoles, but imidazoles are particularly suitable. Examples of imidazoles include 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2 -Phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl- 2-undecylimidazole, 2,4-diamino-6 (2'-methylimidazole (1 ')) ethyl-mesanthine , 2,4-diamino-6 (2'-undecylimidazole (1 ')) ethyl-mesanthine , 2,4-diamino-6 (2'-ethyl-4-methylimidazole (1 ')) ethyl-mesanthine , 2,4-diamino-6 (2'-methylimidazole (1 ')) ethyl-mesanthine / Trimeric isocyanate adduct, 2-methylimidazole trimer isocyanate 2: 3 adduct, 2-phenylimidazole trimer isocyanate adduct, 2-phenyl-3,5 -Dihydroxymethylimidazole, 2-phenyl-4-hydroxymethyl-5-methylimidazole, 1-cyanoethyl-2-phenyl-3,5-dicyanoethoxymethylimidazole, etc. .

[(G) Photo radical polymerization initiator]

The encapsulant for a display of the present invention may contain a photoradical polymerization initiator as a component (G) (hereinafter also simply referred to as "component (G)"). The photoradical polymerization initiator is not particularly limited as long as it is a compound that initiates a chain polymerization reaction due to the generation of radicals or acids due to the irradiation of ultraviolet or visible light, but examples include benzyldimethylketal, 1 -Hydroxycyclohexylphenyl ketone, diethylthiaxanthone, benzophenone, 2-ethylanthraquinone, 2-hydroxy-2-methyl propiophenone, 2-methyl- [4- (methylthio) phenyl] -2-morpholinyl-1-propane, 2,4,6-trimethylbenzylidene diphenylphosphine oxide, camphorquinone (camphorquinone), 9-fluorenone, diphenyl disulfide, and the like. Specific examples include IRGACURE ^RTM 651, 184, 2959, 127, 907, 369, 379EG, 819, 784, 754, 500, OXE01, OXE02, OXE03, OXE04, DAROCURE ^RTM 1173, LUCIRIN ^RTM TPO (all BASF) (Manufactured by the company), SEIKUOL ^RTM Z, BZ, BEE, BIP, BBI (all manufactured by Seiko Chemical Co., Ltd.). Among these, OXE01, OXE02, OXE03, and OXE04 which are oxime ester-based initiators are preferable.

From the viewpoint of liquid crystal contamination, it is preferable to use a (meth) acrylic acid group in the molecule. For example, 2-methacrylic acid can be suitably used. A reaction product of methoxyethyl isocyanate and 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2methyl-1-propane-1-one. This compound can be produced by the method described in International Publication No. 2006/027982.

When the component (G) is used in the display encapsulant of the present invention, the component (G) is usually 0.001 to 3% by mass, and preferably 0.002 to 2% by mass in the total amount of the display encapsulant.

[(H) Thermal radical polymerization initiator]

The encapsulant for a display of the present invention may contain (H) a thermal radical polymerization initiator (hereinafter also simply referred to as "component (H)") in order to improve the hardening rate and hardenability.

The thermal radical polymerization initiator is not particularly limited as long as it is a compound that initiates a chain polymerization reaction due to the generation of radicals by heat. Examples include organic peroxides, azo compounds, benzoin compounds, benzoin ether compounds, and phenethyl Ketone compounds, benzopinacol, etc., and benzopinacol is suitably used. For example, for organic peroxides, Kayamek ^RTM A, M, R, L, LH, SP-30C, Perkadox CH-50L, BC-FF, Kadox 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, Perkadox 16, Kayacarbon ^RTM BIC-75, AIC-75 (made by KAYAKU AKZO Corporation); 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 (manufactured by Nippon Oil Corporation) and other commercially available products.

In addition, azo compounds are commercially available such as VA-044, 086, V-070, VPE-0201, and VSP-1001 (manufactured by Wako Pure Chemical Industries, Ltd.).

In the total amount of the display sealing agent of the present invention, the content of the component (H) is preferably 0.0001 to 10% by mass, more preferably 0.0005 to 5% by mass, and even more preferably 0.001 to 3% by mass.

In the display sealing agent of the present invention, additives such as a radical polymerization inhibitor, a pigment, a leveling agent, an antifoaming agent, and a solvent may be further blended as necessary.

[Free radical polymerization inhibitor]

The above-mentioned radical polymerization inhibitor is not particularly limited as long as it is a compound that prevents polymerization by reacting with a radical generated by a photoradical polymerization initiator, a thermal radical polymerization initiator, or the like, that is, a quinone-based, Pyridine-based, hindered phenol-based, nitroso-based, etc. Specific examples include naphthoquinone, 2-hydroxynaphthoquinone, 2-methylnaphthoquinone, 2-methoxynaphthoquinone, and 2,2,6,6-tetramethylpiperidine-1-oxide. , 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxide, 2,2,6,6-tetramethyl-4-methoxypiperidine-1-oxide, 2 , 2,6,6-Tetramethyl-4-phenoxypiperidine-1-oxide, hydroquinone, 2-methylhydroquinone, 2-methoxyhydroquinone, p-benzoquinone, butylhydroxyl Anisyl ether, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-cresol, stearyl β- (3,5-di-tert-butyl 4-hydroxyphenyl) propionate, 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 4,4'-thiobis (3-methyl-6 -Tertiary butylphenol), 4,4'-butylene bis (3-methyl-6-third butylphenol), 3,9-bis [1,1-dimethyl-2- [β- (3-Third-butyl-4-hydroxy-5-methylphenyl) propanyloxy] ethyl], 2,4,8,10-tetraoxaspiro [5,5] undecane, -[Methylene-3- (3 ', 5'-di-third-butyl-4'-hydroxyphenylpropionate) methane], 1,3,5-ginseng (3', 5'-di -Third-butyl-4'-hydroxybenzyl) -Second-tri -2,4,6- (1H, 3H, 5H) trione, p-methoxyphenol, 4-methoxy-1-naphthol, thiodiphenylamine, N-nitrosophenylhydroxylamine Aluminum salt, trade name Adekastab LA-81, trade name Adekastab LA-82 (manufactured by Adeka Co., Ltd.), and the like, but are not limited to these. Among these are naphthoquinone, hydroquinone, nitroso, and piperidine. A preferred radical polymerization inhibitor is naphthoquinone, 2-hydroxynaphthoquinone, hydroquinone, 2,6-di-third-butyl-p-cresol, Polystop 7300P (made by Bodong Co., Ltd.) as Even better, Polystop 7300P (made by Bodong Co., Ltd.) is the best.

In the total display encapsulant 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, and even more preferably 0.01 to 0.2% by mass.

An example of the method of obtaining the display sealing agent of this invention is as follows. First, if necessary, the component (G) is heated and dissolved in the components (A) and (B). After cooling to room temperature, the components (C), (D), (E), (F), (H), defoaming agent, leveling agent, solvent, etc. are added as necessary. Using a well-known mixing device, For example, a three-roll mill, a sand mill, a ball mill and the like are mixed uniformly and filtered through a metal screen to produce the display sealing agent of the present invention.

Moreover, the sealing compound for displays of the present invention is very suitable as an adhesive for liquid crystal display units, and particularly suitable as a liquid crystal sealant. When the display sealing agent of the present invention is used as a liquid crystal sealant, the liquid The crystal display unit is exemplified below.

A liquid crystal display unit manufactured by using the adhesive for a liquid crystal display unit of the present invention is a pair of substrates having predetermined electrodes formed on the substrates, which are oppositely arranged at a predetermined interval, and the liquid crystal sealant of the present invention is used around the substrate. Sealed, and liquid crystal is sealed in the gap. The type of the enclosed liquid crystal is not particularly limited. The substrate refers to a substrate made of a combination of at least one of light-transmitting glass, quartz, plastic, and polysiloxane. The method is to add a spacer (gap control material) such as glass fiber to the liquid crystal sealant of the present invention, and then apply the liquid crystal sealant to one of the pair of substrates using a disperser or a screen printing device. After that, quasi-hardening is performed at 80 to 120 ° C as necessary. Then, the liquid crystal is dropped to the inside of the weir of the liquid crystal sealant, and another glass substrate is laminated in a vacuum to create a gap. After the gap is formed, the liquid crystal display unit of the present invention can be obtained by curing at 90 to 130 ° C for 30 minutes to 2 hours. Furthermore, when using a photo-thermal combination type, ultraviolet rays can be irradiated on the liquid crystal sealant portion with an ultraviolet irradiator to harden the light. The ultraviolet irradiation amount is preferably 500 to 6,000 mJ / cm ² , and more preferably 1,000 to 4,000 J / cm ² . Then, if necessary, it is hardened at 90 to 130 ° C for 30 minutes to 2 hours, 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 humidity resistance reliability. Examples of the spacer include glass fibers, silica beads, and polymer beads. Although the diameter varies depending on the purpose, it is usually 2 to 8 μm, and preferably 4 to 7 μm. The use amount of the spacer is usually about 0.1 to 4 parts by mass, and preferably about 0.5 to 2 parts by mass, and more preferably about 0.9 to 1.5 parts by mass, with respect to 100 parts by mass of the liquid crystal sealant of the present invention.

The encapsulant for a display of the present invention is very suitable for those who use adhesives in fields that require hardenability, adhesion to different adhesives, and reliability in moisture and heat resistance. Examples include liquid crystal sealants, organic EL encapsulants, and adhesives for touch panels.

[Example]

Hereinafter, although the present invention will be described in more detail through examples, the present invention is not limited to the examples. In addition, unless otherwise specified, the "parts" and "%" in this article are the quality basis.

[Synthesis example 1]

[Acrylation of castor oil modified epoxy resin]

In a flask equipped with a stirring device, a reflux tube, and a thermometer, 104 g of castor oil-modified epoxy resin (product name: EPOX-MKR151, manufactured by Printec Corporation) was dissolved in 120 g of toluene, and added as a polymerization inhibitor. 0.4 g of dibutylhydroxytoluene was heated to 60 ° C. Then, 18.9 g of 100% equivalent of propanoic acid was added to the epoxy group, and the temperature was raised to 80 ° C. Then, 0.6 g of trimethylammonium hydroxide as a reaction catalyst was added thereto, and the mixture was stirred at 98 ° C. for about 40 hours to obtain a reaction. liquid. This reaction solution was washed with water, and toluene was distilled off, thereby obtaining 110 g of a target compound.

[Examples 1 to 2 and Comparative Examples 1 to 5]

The components (A) and (B) are mixed in the ratio shown in Table 1 below, the component (G) is heated and dissolved at 90 ° C, and then cooled to room temperature, and the components (C), (D), and (E) are added ), (F), (H), (O), after stirring, use a three-roll mill These were dispersed and filtered with a metal mesh (635 mesh) to prepare Examples 1 and 2 of a sealing agent for a display. In addition, components (O-3) to (O-6) were used in place of component (A) to prepare Comparative Examples 1 to 5.

[Evaluation]

[Adhesive strength]

(Initial Adhesion Light Directional Film)

Orientation film liquid (manufactured by Nissan Chemical Industries, Ltd .: RN2880) was spin-coated on a glass substrate, preheated at 80 ° C for 3 minutes, and calcined in an oven at 230 ° C for 30 minutes. Then, this substrate with an orientation film was irradiated with 500 mJ / cm ² (measurement wavelength: 254 nm) by a UV irradiator, and then fired in an oven at 230 ° C. for 30 minutes.

To 100 g of the liquid crystal sealant produced in the examples and comparative examples, 5 μm of glass fiber was added as a spacer, and the mixture was stirred. The liquid crystal sealant was coated on a glass substrate coated with an alignment film so as to reproduce a corner portion of 1 cm × 1 cm, and the opposite substrate coated with the alignment film was bonded, and UV irradiation was applied. After the machine was irradiated with 300 mJ / cm ² of ultraviolet rays, it was put into an oven and heat-cured at 120 ° C. for 1 hour. The peeling adhesion strength of the glass substrate coated with the alignment film was measured with a bond tester (manufactured by Nishijin Corporation: SS-30WD) in the form of a pressed corner. The intensity is shown in Table 1.

(PCT followed by intensity light directing film)

A liquid crystal sealant was coated on the above-mentioned orientation film-coated substrate, and a PCT test (condition: temperature 121 ° C., humidity 100%, air pressure 2 atm, test time 12 hours) was performed on the hardened test piece, and the same adhesion strength was measured. . The intensity is shown in Table 1.

[Measurement of glass transition temperature]

The liquid crystal sealants produced in the examples and comparative examples were sandwiched between polyethylene terephthalate (PET) films to form a film having a thickness of 100 μm, and the film was irradiated with 3000 mJ / cm ² of ultraviolet light by a UV irradiator. , Put it into the oven and heat-harden it at 120 ° C for 1 hour. After curing, the PET film was peeled to obtain a sealant cured film, which was then cut into a 50 mm x 5 mm short note shape to form a sample piece. This sample piece was measured in a tensile mode of a dynamic viscoelasticity measuring device (DMS-6100: manufactured by SII Nano technology) under the conditions of a frequency of 10 Hz and a temperature rise temperature of 3 ° C / min. The temperature at the maximum value was obtained as the temperature of the glass transition temperature. The results are shown in Table 1.

[Moisture permeability]

The liquid crystal sealants produced in the examples and comparative examples were sandwiched between polyethylene terephthalate (PET) films to form a film having a thickness of 100 μm, and the film was irradiated with 3000 mJ / cm ² of ultraviolet light by a UV irradiator. , Put it into the oven and heat-harden it at 120 ° C for 40 minutes. After curing, the PET film was peeled to obtain a sample piece. The moisture permeability of the sample piece at 60 ° C. and 90% was measured with a moisture permeability measuring machine (L80-5000, manufactured by Lessy). The results are shown in Table 1.

In the table: B-1-2, moisture permeability (g / m ² * 24 hours)

A-1: Synthesis in Synthesis Example 1 (number of functional groups: 3, number of bisphenol skeletons: 3)

B-1-1: Bisphenol A epoxy acrylate (synthesized by a general synthetic method, for example, Japanese Patent Application Laid-Open No. 2016-24243)

B-1-2: Partial epoxy acrylate of bisphenol A type (synthesized by general synthesis method, for example, 50% equivalent in Japanese Patent Application Laid-Open No. 2016-24243)

C-1: Polymethacrylate-based organic fine particles (manufactured by AICK Industrial Co., Ltd .: F-351S)

D-1: Spherical silicon oxide (manufactured by Tokuyama Corporation: Sansil SSP-07M)

E-1: 3-Glycidoxypropyltrimethoxysilane (JNC Corporation: Sila-Ace S-510)

F-1: 4-hydroxybenzoic acid

G-1: Irgacure OXE04 (manufactured by BASF)

H-1: 1,2-bis (trimethylsilyloxy) -1,1,2,2-tetraphenylethane (Synthesis with reference to Synthesis Example 2 and crushed to an average particle size of 1.9 μm)

O-1: Nitroso-based piperidine derivative (made by Bodong Co., Ltd .: Polystop 7300P)

O-2: 2,4-diamino-6- (2'-methylimidazolyl (1) ') ethyl-mesanthine -Trimeric isocyanate adduct (Shikoku Chemical Co., Ltd .: 2MAOK-PW)

O-3: EB3708 (number of functional groups: 2, number of bisphenol skeletons: 0, manufactured by Daicel-Allnex)

O-4: EB3702 (number of functional groups: 2, number of bisphenol skeletons: 0, manufactured by Daicel-Allnex)

O-5: DPCA-60 (number of functional groups: 6, number of bisphenol skeletons: 0, manufactured by Nippon Kayaku)

O-6: DPCA-120 (number of functional groups: 6, number of bisphenol skeletons: 0, manufactured by Nippon Kayaku)

According to the results of Table 1, the display sealing agent of the present invention achieves characteristics of both high bonding strength and low moisture permeability. Especially in Example 1, the glass transition temperature was also high, and it was considered to be advantageous in terms of long-term high reliability.

[Industrial availability]

The display encapsulant of the present invention is excellent in adhesion strength to an adhesive and has low moisture permeability, so it is particularly suitable as a display encapsulant for displays that require adhesion to an organic film, flexible displays, and curved displays.

Claims (14)

A sealing agent for a display, comprising a component (A), which is a hardening compound having three or more bisphenol skeletons and three or more reactive functional groups in a molecule. The encapsulant for a display according to item 1 of the scope of patent application, wherein two or more of the bisphenol skeletons of the component (A) are bisphenol A skeletons. The encapsulant for a display according to item 1 or 2 of the scope of patent application, wherein the weight average molecular weight of the component (A) is 1,000 or more. The encapsulant for a display according to any one of claims 1 to 3, wherein two or more of the reactive functional groups of the component (A) are (meth) acrylfluorenyl groups. The encapsulant for a display as described in any one of claims 1 to 4, further comprising a component (B), which is a curable compound. The encapsulant for a display according to item 5 of the scope of patent application, wherein the component (B) is a component (B-1), and the component (B-1) is a (meth) acrylic compound. The encapsulant for a display according to item 5 of the scope of patent application, wherein the component (B) is a mixture of the component (B-1) and the component (B-2), and the component (B-1) is (methyl) ) An acrylic compound, and the component (B-2) is an epoxy compound. The encapsulant for a display according to any one of claims 1 to 7 of the patent application scope further contains a component (C), and the component (C) is an organic filler. Seals for displays as described in any of claims 1 to 8 The agent further contains a component (D), which is an inorganic filler. The encapsulant for a display according to any one of claims 1 to 9 of the scope of patent application, further comprising a component (E), which is a silane coupling agent. The encapsulant for a display according to any one of claims 1 to 10 of the scope of patent application, further comprising a component (F), which is a thermosetting agent. The encapsulant for a display according to any one of claims 1 to 11 of the scope of application for a patent, further contains a component (G), which is a photo-radical polymerization initiator. The encapsulant for a display according to any one of claims 1 to 12 of the patent application scope further contains a component (H), which is a thermal radical polymerization initiator. A liquid crystal display is sealed by a sealing agent for a display according to any one of claims 1 to 13.