JP2019137849A - Display sealant - Google Patents

Abstract

To provide a display sealant that can be applied even to a flexible display and a display of a bent shape; more specifically, a display sealant containing a compound having a specific structure in the molecule; wherein, the display sealant can achieve both of flexibility and low moisture permeability, and is suitable as a display sealant of a display required to have adhesion to an organic film and a flexible display, and a display of a bent shape.SOLUTION: A display sealant contains a curable compound. By adding a component (A): 2 mass% of a photoinitiator to the curable compound, and curing it at 3,000 mJ/cmof ultraviolet rays, a resultant cured product has a breaking point elongation of 20% or more and 70% or less.SELECTED DRAWING: None

Description

The present invention relates to a display sealing agent that can be applied to a flexible display or a curved display. More specifically, the present invention relates to a sealant for display that satisfies a specific property in elongation at break. Since this sealing agent for displays can satisfy both flexibility and low moisture permeability, it is particularly useful as a sealing agent for flexible displays and curved displays.
Moreover, since the sealing agent rich in flexibility like this invention is excellent in adhesive strength with a to-be-adhered body, it is useful also in the use as which high adhesive strength is requested | required.

Examples of the display sealant include a liquid crystal display sealant, an organic EL display sealant, and a touch panel adhesive. What is common to these materials is that they have excellent curability but have a characteristic that there is little outgassing and no damage to the display element.
Recently, curved displays and flexible displays have been developed and commercialized. As a substrate used for such a display, a flexible substrate such as a plastic film is used instead of a rigid substrate such as a conventional glass (Patent Document 1).
From such a background, the sealing agent for display is required to have the property of following the deflection of the substrate or the like, that is, the property of being flexible even after curing.

  Moreover, the sealing agent which is excellent in flexibility is advantageous in terms of adhesive strength. For example, it is possible to reduce peeling due to impact and equipment destruction. Also from this point of view, demands for imparting flexibility to the sealant are increasing.

  On the other hand, in order to increase the flexibility of the cured product, it is an effective means to reduce the crosslinking density of the cured product. However, the moisture permeability is usually deteriorated when the crosslinking density is lowered. This is thought to be due to moisture entering from the loose part of the network. Therefore, in order to ensure low moisture permeability, it is necessary to realize contradictory characteristics such as increasing flexibility without decreasing the crosslinking density, or decreasing the crosslinking density but not deteriorating moisture permeability.

  Conventionally, from the viewpoint of improving adhesive strength, a flexible display element adhesive has been developed (Patent Document 2). However, a device having sufficient performance for adapting to the flexible substrate has not been realized yet.

JP 2012-238005 A Japanese Patent Laying-Open No. 2006-24240

  The present invention relates to a display sealing agent that can be applied to a flexible display or a curved display. More specifically, the present invention relates to a sealant for display using a compound having specific performance in breaking elongation. This sealant for display is useful as a sealant for display because it has both flexibility and low moisture permeability.

As a result of intensive studies, the present inventors have found that a sealant for display containing a compound having an elongation at break of a cured product of 20% or more and 70% or less is very excellent in flexibility and low moisture permeability. This has led to the present invention.
That is, the present invention relates to the following [1] to [14]. In the present specification, “(meth) acryl” means “acryl” and / or “methacryl” in the present specification.

[1]
Component (A): a curable compound having an elongation at break of 20% or more and 70% or less of a cured product obtained by adding 2% by mass of a photoinitiator and curing it with ultraviolet light of 3,000 mJ / cm ² ;
A sealant for display containing
[2]
The sealant for display according to [1], wherein the elastic modulus of the component (A) is 10 MPa or more and 1,500 MPa or less.
[3]
The sealant for display according to the above item [1] or [2], wherein the component (A) is a curable compound having two or more reactive double bonds.
[4]
The sealant for display according to any one of [1] to [3], wherein the component (A) is a compound having two or more (meth) acryloyl groups.
[5]
Furthermore, the sealing agent for displays according to any one of [1] to [4] above, further comprising component (B): a curable compound other than component (A).
[6]
The sealant for display according to item [5], wherein the component (B) is a (meth) acrylic compound.
[7]
The sealant for display according to [5], wherein the component (B) is a mixture of a (meth) acrylic compound and an epoxy compound.
[8]
Furthermore, the sealing agent for display as described in any one of said item [1] thru | or [7] containing a component (C) organic filler.
[9]
Furthermore, the sealing agent for display as described in any one of said item [1] thru | or [8] containing a component (D) inorganic filler.
[10]
Furthermore, the sealing agent for displays as described in any one of said item [1] thru | or [9] containing a component (E) silane coupling agent.
[11]
Furthermore, the sealing agent for displays as described in any one of the above-mentioned [1] thru | or [10] containing a component (F) thermosetting agent.
[12]
Furthermore, the sealing agent for displays as described in any one of said item [1] thru | or [11] containing a component (G) radical photopolymerization initiator.
[13]
Furthermore, the sealing agent for displays as described in any one of said item [1] thru | or [12] containing a component (H) thermal radical polymerization initiator.
[14]
A liquid crystal display sealed with the display sealing agent according to any one of [1] to [13].

  Since the sealing agent for displays of the present invention can achieve both flexibility and low moisture permeability, it is useful as a sealing agent for displays.

[(A): A curable compound in which the elongation at break of a cured product obtained by adding 2% by mass of a photoinitiator and curing with ultraviolet light of 3,000 mJ / cm ² is 20% or more and 70% or less]
The sealant for display of the present invention has (A): 2% by mass of a photoinitiator, and a cured product cured at an ultraviolet ray of 3,000 mJ / cm ² has an elongation at break of 20% or more and 70%. It contains the following curable compound (hereinafter also simply referred to as “component (A)”). This compound itself has a certain flexibility and is necessary for obtaining the effects of the present invention. Furthermore, the compound having this characteristic is characterized in that a sufficient effect can be obtained even with a small amount of addition.
In the present invention, unless otherwise noted, the ultraviolet irradiation amount is a value measured at a wavelength of 365 nm.

Component (A) has an elongation at break of 20% or more and 70% or less of a cured product obtained by adding 2% by mass of a photoinitiator and curing it with ultraviolet rays of 3,000 mJ / cm ² . The elongation at break is the elongation at which the cured product breaks in the tensile test, but it does not mean that unilaterally stretched is excellent. In the sealant for display which is the object of the present invention, 20 % To 70% is optimal. The elongation at break is preferably 25% or more and 65% or less, and more preferably 30% or more and 65% or less.
The photoinitiator used here is not particularly limited as long as it generally generates radicals by irradiation with ultraviolet rays or visible rays. For example, IRGACURE ^RTM 651, 184, 2959, 127, 907, 369, 379EG, 819, 784, 754, 500, OXE01, OXE02, OXE03, OXE04, DAROCURE ^RTM 1173, LUCIRIN ^RTM TPO (all manufactured by BASF) and the like. Among these, the case where OXE04 is used is particularly preferable.
Moreover, when making it harden | cure, it is preferable to set it as a film of thickness of 100 micrometers. This is because it is necessary to create a uniform cured product in consideration of light transmittance.
The elastic modulus and elongation at break can be measured by general methods. For example, using a Tensilon universal testing machine (manufactured by A & D Co., Ltd., RTG-1210), at room temperature (22 ° C.), A tensile test can be performed at a test speed of 3 mm / min.

Component (A) preferably has a modulus of elasticity of 10 MPa or more and 1500 MPa or less of a cured product obtained by adding 2% by mass of a photoinitiator and curing it with ultraviolet rays of 3,000 mJ / cm ² . Although a thing with a low elasticity modulus is desired as a curable compound which has a softness | flexibility, in the sealing agent for displays which is the objective of this invention, the minimum of an elasticity modulus is 10 Mpa. The elastic modulus is more preferably 10 MPa or more and 1,300 MPa or less, and particularly preferably 20 MPa or more and 1,000 MPa or less.

  Component (A) has two or more reactive double bonds. A reactive double bond means a vinyl group, an allyl group, a (meth) acryloyl group, or the like. Of these, a (meth) acryloyl group is preferred.

  In addition, preferable content of a component (A) is 5-50 mass% normally in the sealing agent total amount for a display, Preferably it is 5-20 mass%, More preferably, it is 10-20 mass%.

[(B): curable compound other than component (A)]
The sealant for display of the present invention contains a curable compound other than the component (A) (hereinafter also simply referred to as “component (B)”) as the component (B).
Although it will not specifically limit as a component (B) if it is a compound hardened | cured with light, a heat | fever, etc., The case where it is an epoxy compound and a (meth) acryl compound is preferable.
Here, “(meth) acryl” means “acryl” and / or “methacryl” (the same applies hereinafter).

  Although it does not specifically limit as an epoxy compound, The epoxy compound more than bifunctional is preferable, for example, resorcin diglycidyl ether, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolak Type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolak type epoxy resin, bisphenol F novolak type epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, hydantoin Type epoxy resin, isocyanurate type epoxy resin, phenol novolac type epoxy resin having triphenolmethane skeleton, and other bifunctionals such as catechol and resorcinol Diglycidyl ethers of phenol ethers, difunctional alcohols diglycidyl ethers of, and their halides, and the like hydrogenated product. Among these, bisphenol A type epoxy resin and resorcin diglycidyl ether are preferable from the viewpoint of liquid crystal contamination.

Examples of (meth) acrylic compounds include (meth) acrylic ester compounds and epoxy (meth) acrylate compounds.
Specific examples of the (meth) acrylic ester compound include N-acryloyloxyethyl hexahydrophthalimide, acryloylmorpholine, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and cyclohexane-1,4-dimethanol. Mono (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, phenoxyethyl (meth) acrylate, phenyl polyethoxy (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, o-phenylphenol monoethoxy ( (Meth) acrylate, o-phenylphenol polyethoxy (meth) acrylate, p-cumylphenoxyethyl (meth) acrylate, isobornyl (meth) acrylate, tribromophenol Nyloxyethyl (meth) acrylate, dicyclopentanyl (meth) 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 polyethoxydi (meth) acrylate, bisphenol A polypropoxy di (meth) acrylate, bisphenol F Polyethoxydi (meth) acrylate, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, tris (acryloxyethyl) isocyanurate, pentaerythris Tall tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, tripentaerythritol hexa (meth) acrylate, tripentaerythritol penta (meth) acrylate, trimethylolpropane tri (meth) Acrylate, trimethylolpropane polyethoxytri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, neopentyl glycol and hydroxypivalic acid ester diacrylate and neopentyl glycol and hydroxypivalic acid ester ε-caprolactone adduct Mention may be made of monomers such as diacrylate. Preferred examples include N-acryloyloxyethyl hexahydrophthalimide, phenoxyethyl (meth) acrylate, and dicyclopentenyloxyethyl (meth) acrylate.

  An epoxy (meth) acrylate compound is obtained by a well-known method by reaction with an epoxy compound and (meth) acrylic acid. Although it does not specifically limit as an epoxy compound used as a raw material, A bifunctional or more functional epoxy compound is preferable, for example, resorcin diglycidyl ether, bisphenol A type epoxy compound, bisphenol F type epoxy compound, bisphenol S type epoxy compound , Phenol novolac type epoxy compound, cresol novolac type epoxy compound, bisphenol A novolak type epoxy compound, bisphenol F novolak type epoxy compound, alicyclic epoxy compound, aliphatic chain epoxy compound, glycidyl ester type epoxy compound, glycidyl amine type epoxy Compounds, hydantoin type epoxy compounds, isocyanurate type epoxy compounds, phenol novolac type epoxy compounds having a triphenolmethane skeleton, and others Catechol, bifunctional phenols diglycidyl ethers of resorcinol and the like, bifunctional alcohols diglycidyl ethers of, and their halides, and the like hydrogenated product. Of these, bisphenol A type epoxy compounds and resorcin diglycidyl ether are preferred from the viewpoint of liquid crystal contamination.

Moreover, the partial epoxy (meth) acrylate which acrylate-converts a part of epoxy group is used suitably as a component (B). Partial epoxy (meth) acrylate is a mixture of an acrylic compound and an epoxy compound.
Although the ratio of an epoxy group and a (meth) acryloyl group can be adjusted suitably and is not limited, it is preferable that the ratio of acrylation is about 30 to 70%.

  A component (B) may be used independently and may mix 2 or more types. In the sealant for display of the present invention, the amount of component (B) is usually 10 to 80% by mass, preferably 20 to 70% by mass, based on the total amount of the sealant for display.

[(C) Organic filler]
The sealant for display of the present invention may contain an organic filler (hereinafter also simply referred to as “component (C)”) as the component (C). Examples of the organic filler include urethane fine particles, acrylic fine particles, styrene fine particles, styrene olefin fine particles, and silicone fine particles. The silicone 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), and the urethane fine particles are JB- 800T, HB-800BK (Negami Industrial Co., Ltd.), Lavalon ^RTM T320C, T331C, SJ4400, SJ5400, SJ6400, SJ4300C, SJ5300C, SJ6300C (Mitsubishi Chemical) are preferable as styrene fine particles, and Septon ^RTM SEPS2004 as styrene olefin fine particles. SEPS 2063 is preferred.
These organic fillers may be used alone or in combination of two or more. Moreover, it is good also as a core-shell structure using 2 or more types. Of these, acrylic fine particles and silicone fine particles are preferable.
When the above acrylic fine particles are used, it is preferable that the acrylic rubber has a core-shell structure composed of two kinds of acrylic rubbers, and particularly preferably a core layer is n-butyl acrylate and a shell layer is methyl methacrylate. This is sold by Aika Industries as Zefiac ^RTM F-351.
Examples of the silicone fine particles include crosslinked organopolysiloxane powders and linear dimethylpolysiloxane crosslinked powders. Examples of the composite silicone rubber include those obtained by coating the surface of the silicone rubber with a silicone resin (for example, polyorganosilsesquioxane resin). Among these fine particles, a silicone rubber of a linear dimethylpolysiloxane crosslinked powder or a composite silicone rubber fine particle of a silicone resin-coated linear dimethylpolysiloxane crosslinked powder is particularly preferable. These may be used alone or in combination of two or more. Preferably, the rubber powder has a spherical shape with little viscosity increase after addition. In the sealing agent for display of this invention, when using a component (C), it is 5-50 mass% normally in the total amount of the sealing agent for display, Preferably it is 5-40 mass%.

[(D) Inorganic filler]
The sealant for display of the present invention may contain an inorganic filler (hereinafter also simply referred to as component (D)) as component (D). Examples of the inorganic filler contained in the present invention include silica, silicon carbide, silicon nitride, boron nitride, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, magnesium oxide, zirconium oxide, and aluminum hydroxide. , Magnesium hydroxide, calcium silicate, aluminum silicate, lithium aluminum silicate, zirconium silicate, barium titanate, glass fiber, carbon fiber, molybdenum disulfide, asbestos, etc., preferably fused silica, crystalline silica, silicon nitride, nitriding Examples thereof include boron, calcium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, aluminum hydroxide, calcium silicate, and aluminum silicate, and silica, alumina, and talc are preferable. These inorganic fillers may be used in combination of two or more.
If the average particle size of the inorganic filler is too large, it becomes a cause of defects such as failure to form a gap when the upper and lower glass substrates are bonded together during the production of a narrow gap liquid crystal display cell, so 2000 nm or less is appropriate, preferably 1000 nm. Hereinafter, it is more preferably 300 nm or less. Moreover, a preferable minimum is about 10 nm, More preferably, it is about 100 nm. The particle diameter can be measured by a laser diffraction / scattering particle size distribution analyzer (dry type) (manufactured by Seishin Enterprise Co., Ltd .; LMS-30).
In the sealant 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, in the total amount of the sealant for display. When the content of the inorganic filler is lower than 5% by mass, the adhesive strength to the glass substrate is lowered, and the moisture resistance reliability is inferior, so that the decrease in the adhesive strength after moisture absorption may be increased. Moreover, when there is more content of an inorganic filler than 50 mass%, since there is too much filler content, it may become difficult to collapse and it will become impossible to form the gap of a liquid crystal cell.

[(E) Silane coupling agent]
The sealant for display of the present invention can improve adhesion strength and moisture resistance by adding a silane coupling agent (hereinafter also simply referred to as “component (E)”) as the component (E). .
Component (E) includes 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltri Methoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyltrimethoxysilane, 3- Aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, N- (2- (vinylbenzylamino) ethyl) 3-aminopropyltrimethoxysilane hydrochloride, 3-methacryloxypropyltrimethoxysilane, 3-chloropropyl Chill dimethoxysilane, 3-chloropropyl trimethoxy silane, and the like. Since these silane coupling agents are sold by Shin-Etsu Chemical Co., Ltd. as KBM series, KBE series, etc., they are easily available from the market. In the sealing agent for display of this invention, when using a component (E), 0.05-3 mass% is suitable in the sealing agent total amount for display.

[(F) Thermosetting agent]
The display sealant of the present invention can be improved in reactivity by adding a thermosetting agent (hereinafter also simply referred to as “component (F)”) as the component (F).
Examples of the component (F) include compounds having a carboxy group bonded to an aromatic ring in the molecule, polyvalent amines, polyhydric phenols, organic acid hydrazide compounds, and the like. However, it is not limited to these. For example, the aromatic hydrazide terephthalic acid dihydrazide, isophthalic acid dihydrazide, 2,6-naphthoic acid dihydrazide, 2,6-pyridinedihydrazide, 1,2,4-benzenetrihydrazide, 1,4,5,8-naphthoic acid Examples thereof include tetrahydrazide and pyromellitic acid tetrahydrazide. Examples of aliphatic hydrazide compounds include form hydrazide, acetohydrazide, propionic acid hydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, pimelic acid dihydrazide, sebacic acid dihydrazide. 1,4-cyclohexanedihydrazide, tartaric acid dihydrazide, malic acid dihydrazide, iminodiacetic acid dihydrazide, N, N'-hexamethylenebissemicarbazide, citric acid trihydrazide, nitriloacetic acid trihydrazide, cyclohexanetricarboxylic acid trihydrazide, 1,3-bis ( Hydantoin skeleton such as hydrazinocarbonoethyl) -5-isopropylhydantoin, preferably valine hydantoin skeleton (where the carbon atom of the hydantoin ring is iso Dihydrazide compounds having a skeleton substituted with a propyl group), tris (1-hydrazinocarbonylmethyl) isocyanurate, tris (2-hydrazinocarbonylethyl) isocyanurate, tris (1-hydrazinocarbonylethyl) isocyanurate, tris (3-hydrazinocarbonylpropyl) isocyanurate, bis (2-hydrazinocarbonylethyl) isocyanurate and the like can be mentioned. Preferably, from the balance of curing reactivity and latency, isophthalic acid dihydrazide, malonic acid dihydrazide, adipic acid dihydrazide, tris (1-hydrazinocarbonylmethyl) isocyanurate, tris (1-hydrazinocarbonylethyl) isocyanurate, tris ( 2-Hydrazinocarbonylethyl) isocyanurate and tris (3-hydrazinocarbonylpropyl) isocyanurate, particularly preferably tris (2-hydrazinocarbonylethyl) isocyanurate.
As the component (F), a compound having a carboxy group bonded to an aromatic ring in the molecule is preferably used. For example, 4-hydroxybenzoic acid, thiosalicylic acid, terephthalic acid, citrazic acid, 4-aminobenzoic acid, 4 -(Aminomethyl) benzoic acid and 2-mercaptonicotinic acid can be mentioned.
A component (F) may be used independently and may mix 2 or more types. In the sealant for display of the present invention, when component (F) is used, it is usually 0.1 to 10% by mass, preferably 0.1 to 5% by mass, based on the total amount of the sealant for display.

  The sealant for display of the present invention can further improve the reactivity by adding a curing catalyst. Examples of the curing catalyst include amines and imidazoles, and imidazoles are particularly preferable. 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-s-triazine, 2,4-diamino-6- (2′-undecylimidazole (1 ′)) ethyl-s-triazine, 2,4-diamino-6 (2′-ethyl-4-methylimidazole) (1 ′)) Ethyl-s-triazine, 2,4-diamino-6 (2 ′ Methylimidazole (1 ′)) ethyl-s-triazine isocyanuric acid adduct, 2-methylimidazole isocyanuric acid 2: 3 adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-3,5-dihydroxymethyl Examples include imidazole, 2-phenyl-4-hydroxymethyl-5-methylimidazole, and 1-cyanoethyl-2-phenyl-3,5-dicyanoethoxymethylimidazole.

[(G) Photoradical polymerization initiator]
The sealant for display of the present invention may contain a radical photopolymerization initiator (hereinafter also simply referred to as “component (G)”) as the component (G). The radical photopolymerization initiator is not particularly limited as long as it is a compound that generates a radical or an acid upon irradiation with ultraviolet rays or visible light, and initiates a chain polymerization reaction. For example, benzyldimethyl ketal, 1-hydroxycyclohexyl phenyl ketone , Diethylthioxanthone, benzophenone, 2-ethylanthraquinone, 2-hydroxy-2-methylpropiophenone, 2-methyl- [4- (methylthio) phenyl] -2-morpholino-1-propane, 2,4,6- Examples thereof include trimethylbenzoyldiphenylphosphine oxide, camphorquinone, 9-fluorenone, diphenyldisulfide and the like. Specifically, IRGACURE ^RTM 651, 184, 2959, 127, 907, 369, 379EG, 819, 784, 754, 500, OXE01, OXE02, OXE03, OXE04, DAROCURE ^RTM 1173, LUCIRIN ^RTM TPO (all manufactured by BASF ), Sequol ^RTM Z, BZ, BEE, BIP, BBI (all manufactured by Seiko Chemical Co., Ltd.) and the like. Among these, OXE01, OXE02, OXE03, and OXE04 which are oxime ester initiators are preferable.
Moreover, it is preferable to use what has a (meth) acryl group in a molecule | numerator from a liquid crystal contamination viewpoint, for example, 2-methacryloyloxyethyl isocyanate and 1- [4- (2-hydroxyethoxy) -phenyl]- The reaction product with 2-hydroxy-2methyl-1-propan-1-one is preferably used. This compound can be obtained by the method described in International Publication No. 2006/027982.
In the sealant for display of the present invention, when component (G) is used, it is usually 0.001 to 3% by mass, preferably 0.002 to 2% by mass in the total amount of the sealant for display.

[(H) Thermal radical polymerization initiator]
The sealant for display of the present invention contains a thermal radical polymerization initiator (hereinafter also simply referred to as “component (H)”) as the component (H), and can improve the curing speed and curability. .
The thermal radical polymerization initiator is not particularly limited as long as it is a compound that generates radicals by heating and initiates a chain polymerization reaction, but there are organic peroxides, azo compounds, benzoin compounds, benzoin ether compounds, acetophenone compounds, benzopinacols, and the like. And benzopinacol is preferably used. For example, examples of the organic peroxide include Kayamek ^RTM A, M, R, L, LH, SP-30C, Parkadox CH-50L, BC-FF, Kadox B-40ES, Parkadox 14, Trigonox ^RTM 22-70E, 23-C70, 121, 121-50E, 121-LS50E, 21-LS50E, 42, 42LS, Kaya Ester ^RTM P-70, TMPO-70, CND-C70, OO-50E, AN, Kayabutyl ^RTM B, Parkardox 16 , Kayacarbon ^RTM BIC-75, AIC-75 (manufactured by Kayaku Akzo Co., Ltd.), Permec ^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, Parkmill ^RTM H, D, Parroyl ^RTM IB, IPP, Perocta ^RTM ND (manufactured by NOF Corporation) and the like are commercially available.

  As azo compounds, VA-044, 086, V-070, VPE-0201, VSP-1001 (manufactured by Wako Pure Chemical Industries, Ltd.) and the like are commercially available.

  As content of a component (H), it is preferable that it is 0.0001-10 mass% in the total amount of the sealing agent for displays of this invention, More preferably, it is 0.0005-5 mass%. 001-3 mass% is particularly preferable.

  Additives such as a radical polymerization inhibitor, a pigment, a leveling agent, an antifoaming agent, and a solvent can be further blended into the sealant for display of the present invention as necessary.

[Radical polymerization inhibitor]
The radical polymerization inhibitor is not particularly limited as long as it is a compound that prevents polymerization by reacting with radicals generated from a photo radical polymerization initiator or a thermal radical polymerization initiator, and is not limited to quinone, piperidine, A hindered phenol type, a nitroso type, etc. can be used. Specifically, naphthoquinone, 2-hydroxynaphthoquinone, 2-methylnaphthoquinone, 2-methoxynaphthoquinone, 2,2,6,6-tetramethylpiperidine-1-oxyl, 2,2,6,6-tetramethyl-4 -Hydroxypiperidine-1-oxyl, 2,2,6,6-tetramethyl-4-methoxypiperidine-1-oxyl, 2,2,6,6-tetramethyl-4-phenoxypiperidine-1-oxyl, hydroquinone, 2-methylhydroquinone, 2-methoxyhydroquinone, parabenzoquinone, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, 2,6-di-t-butylcresol, stearyl β- (3 5-di-t-butyl-4-hydroxyphenyl) propionate, 2,2′-methylenebis ( -Ethyl-6-tert-butylphenol), 4,4'-thiobis (3-methyl-6-tert-butylphenol), 4,4'-butylidenebis (3-methyl-6-tert-butylphenol), 3,9- Bis [1,1-dimethyl-2- [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl], 2,4,8,10-tetraoxaspiro [5,5 ] Undecane, tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenylpropionate) methane], 1,3,5-tris (3 ′, 5′-di-) t-butyl-4′-hydroxybenzyl) -sec-triazine-2,4,6- (1H, 3H, 5H) trione, paramethoxyphenol, 4-methoxy-1-naphthol, thiodiphenylamine, N-ni Nitroso aluminum salts of phenyl hydroxy amine, trade name ADK STAB LA-81, but such trade name ADK STAB LA-82 (manufactured by KK ADEKA) and the like, but is not limited thereto. Of these, naphthoquinone, hydroquinone, nitroso, and piperazine radical polymerization inhibitors are preferred, and naphthoquinone, 2-hydroxynaphthoquinone, hydroquinone, 2,6-di-tert-butyl-P-cresol, polystop 7300P (Hakuto) More preferably, Polystop 7300P (Hakuto Co., Ltd.) is most preferable.
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 more preferably 0.01 to 0.2% in the total amount of the sealant for display of the present invention. Mass% is particularly preferred.

  As an example of the method for obtaining the sealant for display of the present invention, there is the following method. First, the component (G) is heated and dissolved in the components (A) and (B) as necessary. Next, after cooling to room temperature, components (C), (D), (E), (F), (H), an antifoaming agent, a leveling agent, a solvent, etc. are added as necessary, and a known mixing device, For example, the sealing agent for display of the present invention can be produced by uniformly mixing with a three-roll, sand mill, ball mill or the like and filtering with a metal mesh.

  The sealant for display of the present invention is very useful as an adhesive for liquid crystal display cells, particularly as a liquid crystal sealant. An example is shown below about the liquid crystal display cell when the sealing agent for display of this invention is used as a liquid-crystal sealing agent.

The liquid crystal display cell manufactured using the liquid crystal display cell adhesive of the present invention has a pair of substrates each having a predetermined electrode formed on the substrate so as to face each other at a predetermined interval, and the periphery is sealed with the liquid crystal sealant of the present invention. The liquid crystal is sealed in the gap. The kind of liquid crystal to be sealed is not particularly limited. Here, the substrate is composed of a combination of substrates made of at least one of glass, quartz, plastic, silicon, etc. and having light transmission properties. As a manufacturing method thereof, after adding a spacer (gap control material) such as glass fiber to the liquid crystal sealant of the present invention, the liquid crystal sealant is applied to one of the pair of substrates using a dispenser or a screen printing device. Then, if necessary, temporary curing is performed at 80 to 120 ° C. Thereafter, a liquid crystal is dropped inside the weir of the liquid crystal sealant, and the other glass substrate is overlaid in a vacuum to create a gap. After forming the gap, the liquid crystal display cell of the present invention can be obtained by curing at 90 to 130 ° C. for 30 minutes to 2 hours. When used as a photothermal combination type, the liquid crystal sealant is irradiated with ultraviolet rays by an ultraviolet irradiator and photocured. UV irradiation dose is preferably 500~6000mJ / cm ^2, more preferably the dose of 1000~4000mJ / cm ² is preferred. Then, if necessary, the liquid crystal display cell of the present invention can be obtained by curing at 90 to 130 ° C. for 30 minutes to 2 hours. The liquid crystal display cell of the present invention thus obtained has no display defects due to liquid crystal contamination, and has excellent adhesion and moisture resistance reliability. Examples of the spacer include glass fiber, silica beads, and polymer beads. The diameter varies depending on the purpose, but is usually 2 to 8 μm, preferably 4 to 7 μm. The amount used is usually 0.1 to 4 parts by weight, preferably 0.5 to 2 parts by weight, more preferably about 0.9 to 1.5 parts by weight with respect to 100 parts by weight of the liquid crystal sealant of the present invention. is there.

  The sealant for display of the present invention is very suitable for use in adhesive applications in fields requiring curability, adhesion to different adherends, and resistance to wet heat. For example, a liquid crystal sealant, an organic EL sealant, and a touch panel adhesive.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to an Example. Unless otherwise specified, “part” and “%” in the text are based on mass.

[Synthesis Example 1]
[Synthesis of norbornane acrylate 1]
In a flask equipped with a stirrer, a reflux tube and a thermometer, 11 g of norbornane diisocyanatomethyl (product name: Cosmonate NBDI, manufactured by Mitsui Chemicals) and 41 g of unsaturated fatty acid hydroxyalkyl ester modified ε-caprolactone (product name: Plaxel) FA2D, manufactured by Daicel Corporation) was added and the temperature was raised to 80 ° C., followed by stirring for 5 hours to obtain the desired product.

[Synthesis Example 2]
[Synthesis of norbornane acrylate 2]
In a flask equipped with a stirrer, a reflux tube and a thermometer, 11 g of norbornane diisocyanatomethyl (product name: Cosmonate NBDI, manufactured by Mitsui Chemicals) and 82 g of unsaturated fatty acid hydroxyalkyl ester modified ε-caprolactone (product name: Plaxel) FA5, manufactured by Daicel Corporation) was added and the temperature was raised to 80 ° C., followed by stirring for 5 hours to obtain the desired product.

[Synthesis Example 3]
[Synthesis of norbornane acrylate 3]
In a flask equipped with a stirrer, a reflux tube and a thermometer, 11 g of norbornane diisocyanatomethyl (product name: Cosmonate NBDI, manufactured by Mitsui Chemicals) and 42 g of unsaturated fatty acid hydroxyalkyl ester modified ε-caprolactone (product name: Plaxel) FM2D (manufactured by Daicel Corporation) was added and the temperature was raised to 80 ° C., followed by stirring for 5 hours to obtain the desired product.

[Synthesis Example 4]
[Synthesis of Naphthalene Acrylate 1]
In a flask equipped with a stirrer, a reflux tube and a thermometer, 13 g of 1,5-diisocyanatonaphthalene (manufactured by Tokyo Chemical Industry Co., Ltd.) and 41 g of unsaturated fatty acid hydroxyalkyl ester modified ε-caprolactone (product name: Plaxel FA2D) , Manufactured by Daicel Corporation) and heated up to 80 ° C. and stirred for 5 hours to obtain the desired product.

[Synthesis Example 5]
[Synthesis of Naphthalene Acrylate 2]
In a flask equipped with a stirrer, a reflux tube and a thermometer, 13 g of 1,5-diisocyanatonaphthalene (manufactured by Tokyo Chemical Industry Co., Ltd.) and 82 g of unsaturated fatty acid hydroxyalkyl ester modified ε-caprolactone (product name: Plaxel FA5) , Manufactured by Daicel Corporation) and heated up to 80 ° C. and stirred for 5 hours to obtain the desired product.

[Synthesis Example 6]
[Synthesis of Naphthalene Acrylate 3]
In a flask equipped with a stirrer, a reflux tube and a thermometer, 13 g of 1,5-diisocyanatonaphthalene (manufactured by Tokyo Chemical Industry Co., Ltd.) and 42 g of unsaturated fatty acid hydroxyalkyl ester-modified ε-caprolactone (product name: Plaxel FM2D) , Manufactured by Daicel Corporation) and heated up to 80 ° C. and stirred for 5 hours to obtain the desired product.

[Synthesis Example 7]
[Synthesis of hexamethylene diisocyanate trimer acrylate]
In a flask equipped with a stirrer, a reflux tube and a thermometer, 18 g of hexamethylene diisocyanate trimer (product name: Duranate TLA-100, manufactured by Asahi Kasei Co., Ltd.) and 34 g of unsaturated fatty acid hydroxyalkyl ester modified ε-caprolactone ( Product name: Plaxel FM2D (manufactured by Daicel Corporation) was added, the temperature was raised to 80 ° C., and the mixture was stirred for 6 hours to obtain the desired product.

[Synthesis Example 8]
[Synthesis of polysulfide-modified epoxy resin acrylate]
98 g of polysulfide-modified epoxy resin (product name: Flep 50, manufactured by Toray Fine Chemical Co., Ltd.) was dissolved in 124 g of toluene, 0.4 g of dibutylhydroxytoluene was added thereto as a polymerization inhibitor, and the temperature was raised to 60 ° C. Thereafter, 26 g of acrylic acid with 100% equivalent of epoxy group was added and the temperature was further raised to 80 ° C., 0.6 g of tetrapropylammonium hydroxide as a reaction catalyst was added thereto, and the mixture was stirred at 98 ° C. for about 30 hours, A reaction solution was obtained. This reaction solution was washed with water and toluene was distilled off to obtain the desired product.

[Material characteristics evaluation]
0.2 g of IRGACURE OXE-04 (manufactured by BASF) was added as a photoinitiator to 10 g of each of the compounds synthesized in the above synthesis examples and various acrylic resins available from the market, and the mixture was thermally dissolved at 90 ° C.
The above composition was made into a 100 μm thin film, and irradiated with 3000 mJ / cm ² ultraviolet rays by a UV irradiator, and then the cured film was dumbbell-shaped test piece (total length 75 mm, overall width 10 mm, narrow parallel portion length 50 mm, width 5 mm). To obtain a sample piece. The obtained test piece was subjected to a tensile test using a Tensilon universal testing machine (manufactured by A & D Co., Ltd., RTG-1210) at room temperature (22 ° C.) at a test speed of 5 mm / min. The elastic modulus was calculated from the results of tensile stress and strain within the proportional limit. The results are shown in Table 1.

ＥＢ：ダイセル・オルネクス株式会社製 エベクリルシリーズ
ＵＮ：根上工業株式会社製 アートレジンＵＮシリーズ

EB: Daicel Ornex Co., Ltd. Everkril Series UN: Negami Industrial Co., Ltd. Art Resin UN Series

[Examples 1 to 18, Comparative Examples 1 to 11]
Components (A) and (B) are mixed in the proportions shown in Tables 2 and 3 below, and after component (G) is heated and dissolved at 90 ° C., it is cooled to room temperature, and components (C), (D), ( E), (F) and (H) were added and stirred, and then dispersed with a three-roll mill and filtered through a metal mesh (635 mesh) to prepare Examples 1 to 18. Further, Comparative Examples 1 to 11 were prepared using components (O-3) to (O-9) instead of the component (A).

[Evaluation]
[Adhesive strength]
(Initial adhesive strength Photo-alignment film)
A glass substrate was spin-coated with an alignment film solution (manufactured by Nissan Chemical Industries, Ltd .: RN2880), calcined on an 80 ° C. hot plate for 3 minutes, and baked in a 230 ° C. oven for 30 minutes. Further, the substrate with the alignment film was irradiated with ultraviolet rays of 500 mJ / cm ² (measurement wavelength: 254 nm) with a UV irradiator, and further baked in an oven at 230 ° C. for 30 minutes.
As a spacer, 1 g of 5 μm glass fiber is added to 100 g of the liquid crystal sealant produced in Examples and Comparative Examples, and mixed and stirred. This liquid crystal sealant is applied on a glass substrate coated with an alignment film in a form that reproduces a 1 cm × 1 cm corner portion, and the opposite alignment film coated substrate is bonded and irradiated with 3000 mJ / cm ² of ultraviolet rays by a UV irradiation machine. Then, it was put into an oven and thermally cured at 120 ° C. for 1 hour. The orientation adhesion strength of the glass substrate coated with the alignment film was measured with a bond tester (manufactured by Seishin Shoji Co., Ltd .: SS-30WD) by pressing the corner portion. The strength is shown in Tables 2 and 3.
(Adhesive strength after PCT, photo-alignment film)
A liquid crystal sealant was applied to the alignment film-coated substrate, and the cured test piece was subjected to a PCT test (conditions: temperature 121 ° C., humidity 100%, atmospheric pressure 2 atm, test time 12 hours), and the adhesive strength was measured in the same manner. The strength is shown in Tables 2 and 3.
[Glass transition temperature measurement]
The liquid crystal sealant produced in Examples and Comparative Examples was sandwiched between polyethylene terephthalate (PET) films, and a thin film with a thickness of 100 μm was irradiated with 3000 mJ / cm ² of ultraviolet rays with a UV irradiator and then put into an oven. Heat-cured at 120 ° C. for 1 hour. After curing, the PET film was peeled off to obtain a cured sealant film, which was then cut into a 50 mm × 5 mm strip to obtain a sample piece. This sample piece was measured in a tensile mode of a dynamic viscoelasticity measuring apparatus (DMS-6100: manufactured by SII Nano Technology) under the conditions of a frequency of 10 Hz and a temperature rising temperature of 3 ° C./min, a loss factor tan δ, The temperature was the maximum value in the tan δ curve, and the result was obtained as the glass transition temperature. The results are shown in Tables 2 and 3.
[Moisture permeability]
The liquid crystal sealant produced in Examples and Comparative Examples was sandwiched between polyethylene terephthalate (PET) films, and a thin film having a thickness of 100 μm was irradiated with 3000 mJ / cm ² of ultraviolet rays using a UV irradiator, and then placed in an oven. Heat cured at 1 ° C. for 1 hour, and after curing, the PET film was peeled off to prepare a sample. The moisture permeability of the sample at 60 ° C. and 90% was measured with a moisture permeability measuring device (Lessy Corporation: L80-5000). The results are shown in Tables 2 and 3.

  From the results shown in Table 1, the sealant for display of the present invention is considered to be advantageous in terms of high adhesive strength, low moisture permeability, high glass transition temperature, and long-term high reliability. It is done.

  The sealant for display according to the present invention is excellent in adhesive strength with an adherend and has low moisture permeability, so that a display or flexible display that requires adhesion to an organic film, a curved display, etc. It is useful as a sealant for display.

Claims (14)

Component (A): a curable compound having an elongation at break of 20% or more and 70% or less of a cured product obtained by adding 2% by mass of a photoinitiator and curing it with ultraviolet light of 3,000 mJ / cm ² ;
A sealant for display containing   The sealant for display according to claim 1, wherein the elastic modulus of the component (A) is from 10 MPa to 1,500 MPa.   The sealant for display according to claim 1, wherein the component (A) is a curable compound having two or more reactive double bonds.   The sealant for display according to any one of claims 1 to 3, wherein the component (A) is a compound having two or more (meth) acryloyl groups.   Furthermore, the sealing agent for displays as described in any one of Claims 1 thru | or 4 which contains curable compounds other than component (B): component (A).   The sealant for display according to claim 5, wherein the component (B) is a (meth) acrylic compound.   The sealant for display according to claim 5, wherein the component (B) is a mixture of a (meth) acrylic compound and an epoxy compound.   Furthermore, the sealing agent for displays as described in any one of Claims 1 thru | or 7 containing a component (C) organic filler.   Furthermore, the sealing agent for displays as described in any one of Claims 1 thru | or 8 containing a component (D) inorganic filler.   Furthermore, the sealing agent for displays as described in any one of Claims 1 thru | or 9 containing a component (E) silane coupling agent.   Furthermore, the sealing agent for displays as described in any one of Claims 1 thru | or 10 containing a component (F) thermosetting agent.   Furthermore, the sealing agent for displays as described in any one of Claims 1 thru | or 11 containing a component (G) radical photopolymerization initiator.   Furthermore, the sealing agent for displays as described in any one of Claims 1 thru | or 12 containing a component (H) thermal radical polymerization initiator.   A liquid crystal display sealed with the sealant for display according to any one of claims 1 to 13.