JP2022161206A - Encapsulant for display - Google Patents

Abstract

To provide an encapsulant for display applicable to a flexible display and a curved display, more specifically, an encapsulant for display containing a curable compound and a polymerization initiator with an aromatic ring equivalent of the curable compound of 230 g/eq or more and 270 g/eq or less, achieving both of flexibility and low moisture permeability, and excellent in adhesiveness.SOLUTION: An encapsulant for display contains (A) a curable compound and (B) a polymerization initiator. The component (A) has an aromatic ring equivalent of 230 g/eq or more and 270 g/eq or less.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a display sealant that can be applied to flexible displays and curved displays. Since this sealant for displays can achieve both flexibility and low moisture permeability, it is particularly useful as a sealant for flexible displays and curved displays.
In addition, since the sealing agent having high flexibility like the present invention has excellent adhesiveness to adherends, it is also useful in applications where high adhesive strength is required.

The display sealant includes, for example, a liquid crystal display sealant, an organic EL display sealant, and a touch panel adhesive. What these materials have in common is that they are required to have properties such as excellent curability, low outgassing, and no damage to display elements.
Recently, curved displays and highly flexible displays have been developed and commercialized. Substrates used in such displays are flexible, such as plastic films, instead of conventional rigid substrates such as glass (Patent Document 1).
Against this background, sealants for displays are required to have properties such that they follow the bending of substrates and the like, that is, they are flexible even after curing.

In addition, a sealant having excellent flexibility is also advantageous in adhesive strength. For example, it is possible to reduce detachment and equipment damage due to impact. From this point of view as well, there is an increasing demand for imparting flexibility to sealants.

On the other hand, in order to increase the flexibility of the cured product, it is an effective means to lower the crosslink density of the cured product. However, when the crosslink density is lowered, the moisture permeability is usually deteriorated. It is considered that this is because moisture penetrates through loose portions of the crosslinked network of the cured product. Therefore, in order to ensure low moisture permeability, it is necessary to realize contradictory characteristics, namely, increasing flexibility without lowering the crosslink density, or lowering the crosslink density but not deteriorating the moisture permeability.

Conventionally, from the viewpoint of improving adhesive strength, development of adhesives for display elements having flexibility has been carried out (Patent Document 2). However, a device with sufficient performance to adapt to the above flexible substrate has not yet been realized.

JP 2012-238005 A JP 2016-24240 A

TECHNICAL FIELD The present invention relates to a display sealant that can be applied to flexible displays and curved displays. More specifically, the present invention relates to a sealant for display containing a curable compound and a polymerization initiator, wherein the aromatic ring equivalent of the curable compound is 230 g/eq or more and 270 g/eq or less. An object of the present invention is to provide a sealant for displays that is compatible with wettability and has excellent adhesiveness.

As a result of extensive studies, the present inventors have found that a display sealant containing a curable compound and a polymerization initiator and having an aromatic ring equivalent of 230 g/eq or more and 270 g/eq or less of the curable compound is flexible. The inventors have found that both low moisture permeability and excellent adhesiveness are achieved, leading to the present invention.
In this specification, "(meth)acrylate" means "acrylate" and/or "methacrylate".

That is, the present invention relates to the following [1] to [12].
[1]
A display sealant comprising (A) a curable compound and (B) a polymerization initiator, wherein the component (A) has an aromatic ring equivalent of 230 g/eq or more and 270 g/eq or less.
[2]
The sealant for displays according to the preceding item [1], wherein the component (A) has a (meth)acrylic equivalent of 400 g/eq or more and 600 g/eq or less.
[3]
The display sealant according to the preceding item [1] or [2], which contains a urethane (meth)acrylate as the component (A).
[4]
The display sealing according to the preceding item [3], wherein the urethane (meth)acrylate contains a urethane (meth)acrylate obtained by reacting a polyol having an aromatic ring, an organic polyisocyanate, and a hydroxyl group-containing (meth)acrylate. agent.
[5]
The sealant for displays according to the preceding item [4], wherein the polyol having an aromatic ring comprises a polyol and a dibasic acid having an aromatic ring or an anhydride thereof.
[6]
The display sealant according to any one of the preceding items [1] to [5], which contains a partial epoxy (meth)acrylate as the component (A).
[7]
The sealant for displays according to any one of the preceding items [1] to [6], further comprising component (C) an organic filler.
[8]
The display encapsulant according to the preceding item [7], wherein the component (C) is one or more organic fillers selected from the group consisting of urethane fine particles, acrylic fine particles, styrene fine particles, styrene olefin fine particles, and silicone fine particles. agent.
[9]
The sealant for displays according to any one of the preceding items [1] to [8], further comprising component (D) a thermosetting agent.
[10]
The sealant for displays according to any one of the preceding items [1] to [9], which contains a photoradical polymerization initiator or a thermal radical polymerization initiator as the component (B).
[11]
The display sealant according to any one of the preceding items [1] to [10], which is a liquid crystal sealant for a liquid crystal dropping method.
[12]
A liquid crystal display sealed with the liquid crystal sealant for liquid crystal dripping method according to the preceding item [11].

The display sealant of the present invention can provide a display sealant that has both flexibility and low moisture permeability and is also excellent in adhesiveness.

The display sealant of the present invention comprises (A) a curable compound (hereinafter also simply referred to as "component (A)") and (B) a polymerization initiator (hereinafter simply referred to as "component (B)"). ), and the aromatic ring equivalent of the curable compound is 230 or more and 270 or less.

[(A) curable compound]
Component (A) is not particularly limited as long as it is a compound that is cured by light, heat, or the like, but is preferably a (meth)acrylate, such as (meth)acrylate, urethane (meth)acrylate, epoxy (meth)acrylate. Acrylate, epoxy resin, and the like.

[Urethane (meth)acrylate]
The urethane (meth)acrylate is not particularly limited as long as it has a urethane bond in the molecule, but it is preferably composed of a polyol, an organic polyisocyanate and a hydroxyl group-containing (meth)acrylate, and the polyol has an aromatic ring. It is more preferable to have In this case, since it has a flexible skeleton peculiar to the urethane structure and also has an aromatic ring as a polyol component, the cured product has the characteristics of flexibility and low moisture permeability, and has high adhesion not only on glass substrates but also on alignment films. This is because it has strength.

As for the flexibility, the elastic modulus of the cured product can be used as an index. The elastic modulus of a cured product with a thickness of 100 μm obtained by curing under conditions of 130° C. for 40 minutes after irradiation with ultraviolet rays of 3000 mJ/cm ² (measurement wavelength: 365 nm) is preferably 400 or more and 3200 MPa or less at room temperature (25° C.). It is more preferably 500 or more and 3000 MPa or less, particularly preferably 800 or more and 2800 MPa or less, and most preferably 1000 or more and 2600 MPa or less. It can be said that the display adhesive within the above range is preferable because it can follow the stress applied to the display.
Regarding the moisture permeability, the moisture permeability of a cured product having a thickness of 300 μm under an environment of 60° C. and 90% RH is preferably 60 g/m ² *24 h or less, more preferably 55 g/m ² *24 h or less, 50 g/m ² *24 h or less is particularly preferred.
The adhesiveness is preferably 2.0 kg or more, more preferably 2.1 kg or more, and particularly preferably 2.2 kg or more on the alignment film. The adhesion test of the present application was conducted using NRB-U738 manufactured by Nissan Chemical Industries, Ltd. as the alignment film liquid.

A urethane (meth)acrylate can be obtained by synthesizing a polyol, an organic polyisocyanate and a hydroxyl group-containing (meth)acrylate in a conventional manner.
It is preferable to react 1.1 to 2.0 equivalents of the isocyanate groups of the organic polyisocyanate, particularly preferably 1.3 to 2.0 equivalents, with respect to 1 equivalent of the hydroxyl groups of the polyol. The reaction temperature is preferably room temperature (25°C) to 100°C.
It is preferable to react 0.95 to 1.1 equivalents of hydroxyl groups in the hydroxyl group-containing (meth)acrylate per equivalent of isocyanate groups in the reaction product of the polyol and the organic polyisocyanate. The reaction temperature is preferably room temperature (25°C) to 100°C.

Specific examples of polyols include tricyclodecanedimethanol, hydrogenated polybutadiene polyol, dimer diol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,4-butanediol, and neopentyl. Glycol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,14-tetradecanediol, 1,16-hexadecanediol , 1,18-octadecanediol, 1,20-icosanediol, 1-methyl-1,8-octanediol, 2-methyl-1,8-octanediol, 3-methyl-1,5-pentanediol, 2 ,4-diethyl-1,5-pentanediol, cyclohexane-1,4-dimethanol, polyethylene glycol, polypropylene glycol, bisphenol A poly(n≈2-20) ethoxydiol, bisphenol A poly(n≈2-20) Diols such as propoxydiol, these diols and dibasic acids or their anhydrides (for example, succinic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, isophthalic acid, terephthalic acid, phthalic acid, or their anhydrides) Polyester polyol etc. which are reactants can be mentioned.
Among these, polyester polyols and polyols having an aromatic ring are preferred, and polyester polyols having an aromatic ring are particularly preferred. Examples of aromatic rings include aromatic hydrocarbon rings such as benzene ring, naphthalene ring, anthracene ring, and phenanthroline ring; aromatic rings such as furan ring, pyrrole ring, thiophene ring, pyridine ring, thiazole ring, and benzothiazole ring; A heterocyclic ring is included, preferably a benzene ring or a naphthalene ring.
The polyester polyol having an aromatic ring is preferably a dibasic acid or an anhydride thereof having an aromatic ring. Examples thereof include isophthalic acid, terephthalic acid, orthophthalic acid and anhydride thereof. In addition, polyol may be used independently and may mix two or more types.

Specific examples of organic polyisocyanates include tolylene diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, xylylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′-cyclohexylmethane diisocyanate, xylylene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, trimethylhexamethylene diisocyanate, dimeryl diisocyanate, 1,5-naphthalene diisocyanate, 3,3'-dimethyl-4,4'-diphenylene diisocyanate and the like. be able to. Preferred are tolylene diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate and trimethylhexamethylene diisocyanate, and particularly preferred is tolylene diisocyanate having an aromatic ring.

Specific examples of hydroxyl group-containing (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 1,4-butanediol (meth)acrylate, polyethylene glycol mono(meth)acrylate, and polypropylene. Glycol mono(meth)acrylate, pentaerythritol tri(meth)acrylate, ε-caprolactone adduct of 2-hydroxyethyl(meth)acrylate, 2-hydroxy-3-phenyloxypropyl(meth)acrylate and the like can be mentioned. Preferred are 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate and polyethylene glycol mono(meth)acrylate.

[(Meth)acrylate]
Specific examples of (meth)acrylic esters include N-acryloyloxyethylhexahydrophthalimide, acryloylmorpholine, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, cyclohexane-1,4-dimethanol mono (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, phenoxyethyl (meth) acrylate, phenylpolyethoxy (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, tribromophenyloxyethyl (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, tricyclodecanedimethanol (meth)acrylate, bisphenol A polyethoxydi(meth)acrylate, bisphenol A polypropoxydi(meth)acrylate, bisphenol F polyethoxydi(meth)acrylate, ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, tris(acryloxyethyl)isocyanurate, pentaerythritol 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, Monomers such as the diacrylate of the ε-caprolactone adduct of an ester of neopentyl glycol and hydroxypivalic acid can be mentioned. Preferably, N-acryloyloxyethylhexahydrophthalimide, phenoxyethyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, o-phenylphenol monoethoxy (meth)acrylate, o-phenylphenol polyethoxy (meth)acrylate can be mentioned.
Epoxy (meth)acrylates are obtained by known methods by reacting epoxy resins with (meth)acrylic acid. The epoxy resin used as a raw material is not particularly limited, but is preferably a bifunctional or higher epoxy resin, such as resorcinol diglycidyl ether, bisphenol A type epoxy resin, bisphenol 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 novolak type epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy Resins, hydantoin-type epoxy resins, isocyanurate-type epoxy resins, phenol novolac-type epoxy resins having a triphenolmethane skeleton, other diglycidyl ethers of bifunctional phenols such as catechol and resorcinol, diglycidyl ethers of bifunctional alcohols compounds, and halides and hydrogenated products thereof. Among these, bisphenol A type epoxy resin and resorcinol diglycidyl ether are preferable from the viewpoint of liquid crystal contamination. Moreover, the ratio of the epoxy group and the (meth)acryloyl group is not limited, and is appropriately selected from the viewpoint of process compatibility.
In addition, a partial epoxy (meth)acrylate in which a part of the epoxy group is acryl-esterified is preferably used. In this case, the acrylation rate is preferably 30 to 70%, more preferably 40 to 60%.

[Epoxy resin]
As an embodiment of the present invention, it is preferable that the component (A) further contains an epoxy resin.
Although the epoxy resin is not particularly limited, a bifunctional or higher epoxy resin is preferable. Epoxy resin, cresol novolak 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, glycidylamine type epoxy resin, hydantoin type Epoxy resins, isocyanurate-type epoxy resins, phenolic novolac-type epoxy resins having a triphenolmethane skeleton, diglycidyl-etherified products of bifunctional phenols such as catechol and resorcinol, diglycidyl-etherified products of bifunctional alcohols, and these Halides and hydrogenated products of Among these, bisphenol A type epoxy resin and resorcinol diglycidyl ether are preferable from the viewpoint of liquid crystal contamination.

A preferable content of component (A) is usually 20 to 90% by mass, preferably 40 to 85% by mass, more preferably 50 to 80% by mass, based on the total amount of the sealant for display.

The aromatic ring equivalent weight of the curable compound is obtained by dividing the molecular weight of the curable compound by the number of aromatic rings in the molecule. In the present invention, when the curable compound contains condensed rings, the number of aromatic rings contained in the condensed rings is counted. For example, when the condensed ring is a structure derived from naphthalene, the number of aromatic rings in the structure derived from naphthalene is two. When the condensed ring is an anthracene-derived structure, the anthracene-derived structure has three aromatic rings.
The aromatic ring equivalent of the curable compound can be obtained by the following formula (1). Its unit is g/eq.
Aromatic ring equivalent [g/eq]={molecular weight [g/mol]/number of aromatic rings contained in one molecule (eq/mol)} Formula (1)
The molecular weight of each curable compound is preferably measured by GPC (gel permeation chromatography) using polystyrene as a standard. In this case, the number average molecular weight and the weight average molecular weight are calculated, but the aromatic ring equivalent is preferably calculated from the weight average molecular weight.

When the curable compound of the following formula (2) has a repeating structure, the number of aromatic rings is represented by the following formula (3).
M−(A−B) n−M Formula (2)
(Here, M is a terminal group, A and B are structural formulas, and n is a repeat.)
Aromatic ring number = (xNA × X + yNB × Y) × (weight average molecular weight - Mm) / (xA × X + yB × Y) Formula (3)
(where xA is the molecular weight of the structure of A, yB is the molecular weight of the structure of B, Mm is the molecular weight of the terminal group, X is the ratio of A contained in the structural formula, Y is the ratio of B contained in the structural formula , represents the number of aromatic rings contained in the structure of xNA=A, and the number of aromatic rings contained in the structure of yNB=B.)

When multiple types of compounds are used as the curable compound of the present invention, the aromatic ring equivalent is calculated as follows. For example, the aromatic ring equivalent of a curable compound produced by using compound C and compound D in combination is determined by the following formula (4).
Aromatic ring equivalent of curable compound=total weight of curable compound/(c/aromatic ring equivalent of compound C+d/aromatic ring equivalent of compound D) Formula (4)
(Here, c represents the amount of compound C added, and d represents the amount of compound D added.)

The aromatic ring equivalent is preferably 230 g/eq or more and 270 g/eq or less, more preferably 235 g/eq or more and 250 g/eq or less.
When the aromatic ring equivalent is less than 230 g/eq, the density of the aromatic rings becomes high, and the flexibility of the sealant for display is lowered, resulting in lower adhesive strength. On the other hand, if the aromatic ring equivalent is more than 270 g/eq, the aromatic ring density becomes low and the moisture permeability deteriorates.

The (meth)acrylic equivalent of a curable compound is obtained by dividing the molecular weight of the curable compound by the number of (meth)acrylic groups in the molecule, and its unit is g/eq. The molecular weight of each curable compound is preferably measured by GPC (gel permeation chromatography) using polystyrene as a standard. In this case, the number average molecular weight and the weight average molecular weight are calculated, but the (meth)acrylic equivalent is preferably calculated from the weight average molecular weight.

When using multiple types of compounds as the curable compound of the present invention, the (meth)acrylic equivalent is calculated as follows. For example, the (meth)acrylic equivalent of the curable compound produced by using compound C and compound D in combination is determined by the following formula (5).
(Meth)acrylic equivalent of curable compound=total weight of curable compound/(c/(meth)acrylic equivalent of compound C+d/(meth)acrylic equivalent of compound D) Formula (5)
(Here, c represents the amount of compound C added, and d represents the amount of compound D added.)

The (meth)acrylic equivalent is preferably 400 g/eq or more and 600 g/eq or less, more preferably 420 g/eq or more and 580 g/eq or less, particularly preferably 440 g/eq or more and 520 g/eq or less, and most preferably 450 g/eq or more. 500 g/eq or less.
When the (meth)acrylic equivalent is less than 400 g/eq, curing shrinkage reduces adhesive strength. On the other hand, if the (meth)acrylic equivalent is more than 600 g/eq, the crosslink density will decrease and the moisture permeability will deteriorate.

The sealant for displays of the present invention contains a polymerization initiator as component (B) (hereinafter also simply referred to as "component (B)"). Component (B) is not limited as long as it initiates the curing reaction of component (A), but specific examples include photoradical polymerization initiators and thermal radical polymerization initiators.

[Radical photopolymerization initiator]
The photoradical polymerization initiator is not particularly limited as long as it is a compound that generates radicals or acids upon irradiation with ultraviolet light or visible light and initiates a chain polymerization reaction. Examples include benzyl dimethyl ketal and 1-hydroxycyclohexyl phenyl ketone. , diethylthioxanthone, benzophenone, 2-ethylanthraquinone, 2-hydroxy-2-methylpropiophenone, 2-methyl-[4-(methylthio)phenyl]-2-morpholino-1-propane, 2,4,6- 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 ), Seikuol ^RTM Z, BZ, BEE, BIP, BBI (all manufactured by Seiko Chemical Co., Ltd.), Kayacure DETX-S (manufactured by Nippon Kayaku Co., Ltd.), and the like. Among these, the oxime ester initiators IRGACURE ^RTM OXE01, OXE02, OXE03, OXE04 and the thioxanthone initiator Kayacure DETX-S are preferred.
Furthermore, by using an oxime ester-based initiator and a thioxanthone-based initiator in combination, it is possible to achieve both rapid curability and light-shielding part curability, and it is also preferable because it can be cured with visible light.
In the display sealant of the present invention, when a photoradical polymerization initiator is used, it is usually 0.001 to 3% by mass, preferably 0.01 to 2% by mass, based on the total amount of the display sealant. .

[Thermal radical polymerization initiator]
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 organic peroxides, azo compounds, benzoin compounds, benzoin ether compounds, acetophenone compounds, benzopinacol, etc. benzopinacol is preferably used. For example, organic peroxides include Kayamec ^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, Parkadox 16 , Kayacarbon ^RTM BIC-75, AIC-75 (manufactured by Kayaku 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, Permyl ^RTM H, D, Perroyl ^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.

The content of the thermal radical polymerization initiator is preferably 0.0001 to 10% by mass, more preferably 0.0005 to 3% by mass, based on the total amount of the sealant for display of the present invention. 0.001 to 1% by weight is particularly preferred.
[(C) organic filler]
The sealant for displays of the present invention may contain an organic filler (hereinafter also simply referred to as "component (C)") as 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. KMP-594, KMP-597, KMP-598 (manufactured by Shin-Etsu Chemical Co., Ltd.), Torayfil ^RTM E-5500, 9701 and EP-2001 (manufactured by Dow Corning Toray Co., Ltd.) are preferred as the fine silicone particles, and JB- 800T, HB-800BK (Neagari Kogyo Co., Ltd.), Lavalon ^RTM T320C, T331C, SJ4400, SJ5400, SJ6400, SJ4300C, SJ5300C, and SJ6300C (manufactured by Mitsubishi Chemical) are preferable as styrene fine particles, and Septon ^RTM SEPS2004, as styrene olefin fine particles. SEPS2063 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. Among these, acrylic fine particles and silicone fine particles are preferred.
When the 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, the core layer is n-butyl acrylate and the shell layer is methyl methacrylate. This is marketed by Aica Kogyo Co., Ltd. as Zephiac ^RTM F-351.
Examples of the fine silicone particles include organopolysiloxane crosslinked powders and linear dimethylpolysiloxane crosslinked powders. Composite silicone rubbers include those obtained by coating the surface of the silicone rubber with a silicone resin (for example, polyorganosilsesquioxane resin). Among these fine particles, particularly preferred are silicone rubber particles of linear dimethylpolysiloxane crosslinked powder or composite silicone rubber particles of silicone resin-coated linear dimethylpolysiloxane crosslinked powder. These things may be used independently and may use 2 or more types together. Further, preferably, the shape of the rubber powder is spherical so that the increase in viscosity after addition is small. When component (C) is used in the display sealant of the present invention, it is preferably 1 to 30% by mass, more preferably 2 to 10% by mass, of the total amount of the display sealant. preferable.

[(D) Thermosetting agent]
The sealant for displays of the present invention can be improved in reactivity by adding a thermosetting agent (hereinafter also simply referred to as "component (D)") as component (D).
Examples of component (D) include compounds having a carboxy group bonded to an aromatic ring in the molecule, polyvalent amines, polyvalent phenols, organic acid hydrazides, and the like. However, it is not limited to these. For example, the aromatic hydrazides terephthalic acid dihydrazide, isophthalic acid dihydrazide, 2,6-naphthoic acid dihydrazide, 2,6-pyridinedihydrazide, 1,2,4-benzenetrihydrazide, 1,4,5,8-naphthoic acid Tetrahydrazide, pyromellitic acid tetrahydrazide and the like can be mentioned. Examples of aliphatic hydrazides include formhydrazide, acetohydrazide, propionic 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(hydrazide dihydrazide and tris(1-hydrazinocarbonylmethyl)isocyanurate having a hydantoin skeleton such as dinocarbonoethyl)-5-isopropylhydantoin, preferably a valine hydantoin skeleton (a skeleton in which a carbon atom of the hydantoin ring is substituted with an isopropyl group) , tris (2-hydrazinocarbonylethyl) isocyanurate, tris (1-hydrazinocarbonylethyl) isocyanurate, tris (3-hydrazinocarbonylpropyl) isocyanurate, bis (2-hydrazinocarbonylethyl) isocyanurate, etc. I can give From the balance between 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, tris(3-hydrazinocarbonylpropyl)isocyanurate, particularly preferably tris(2-hydrazinocarbonylethyl)isocyanurate.
As the component (D), it is preferable to use a compound having a carboxy group bonded to an aromatic ring in the molecule. -(Aminomethyl)benzoic acid, 2-mercaptonicotinic acid.
Component (D) may be used alone or in combination of two or more. In the sealant for display of the present invention, when component (D) is used, it is preferably 0.1 to 10% by mass, preferably 0.1 to 5% by mass, based on the total amount of the sealant for display. is more preferred.

A curing catalyst can be added to the display sealant of the present invention to further improve reactivity. Examples of the curing catalyst include amines and imidazoles, and imidazoles are particularly preferred. 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, 2:3 adduct of 2-methylimidazole isocyanuric acid , 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-3,5-dihydroxymethylimidazole, 2-phenyl-4-hydroxymethyl-5-methylimidazole, 1-cyanoethyl-2-phenyl-3,5-dicyanoethoxy and methylimidazole.

[(O) other components]
Additives such as inorganic fillers, silane coupling agents, radical polymerization inhibitors, pigments, leveling agents, antifoaming agents, and solvents can be added to the sealant for displays of the present invention, if necessary. .

[Inorganic filler]
Examples of the inorganic filler include silica, silicon carbide, silicon nitride, boron nitride, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, magnesium oxide, zirconium oxide, aluminum hydroxide, and magnesium hydroxide. , calcium silicate, aluminum silicate, lithium aluminum silicate, zirconium silicate, barium titanate, glass fiber, carbon fiber, molybdenum disulfide, asbestos, preferably fused silica, crystalline silica, silicon nitride, boron nitride, calcium carbonate. , barium sulfate, calcium sulfate, mica, talc, clay, alumina, aluminum hydroxide, calcium silicate and aluminum silicate, preferably silica, alumina and talc. 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 may cause defects such as failure to properly form a gap when the upper and lower glass substrates are bonded together when manufacturing a liquid crystal display cell with a narrow gap. 300 nm or less, and more preferably 300 nm or less. A preferred lower limit is about 10 nm, more preferably about 100 nm. The particle size can be measured with a laser diffraction/scattering particle size distribution analyzer (dry type) (manufactured by Seishin Enterprise Co., Ltd.; LMS-30).
When the inorganic filler is used in the display sealant of the present invention, it is usually 5 to 50% by mass, preferably 5 to 40% by mass, based on the total amount of the display sealant. If the content of the inorganic filler is less than 5% by mass, the adhesion strength to the glass substrate is lowered, and the moisture resistance reliability is also inferior, so that the adhesion strength after moisture absorption may be greatly reduced. Moreover, when the content of the inorganic filler is more than 50% by mass, the content of the filler is too large, so that the liquid crystal cell may not be easily crushed and the gap formation of the liquid crystal cell may not be possible.

[Silane coupling agent]
Examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, 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-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane and the like. These silane coupling agents are sold as KBM series, KBE series, etc. by Shin-Etsu Chemical Co., Ltd., etc., and are readily available on the market. When a silane coupling agent is used in the display sealant of the present invention, it is preferably 0.05 to 3% by mass based on the total amount of the display sealant.

[Radical polymerization inhibitor]
The radical polymerization inhibitor is not particularly limited as long as it is a compound that reacts with radicals generated from a radical photopolymerization initiator, a thermal radical polymerization initiator, or the like to prevent polymerization. Hindered phenol type, nitroso type and the like 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(4-ethyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol) , 4,4′-butylidenebis(3-methyl-6-t-butylphenol), 3,9-bis[1,1-dimethyl-2-[β-(3-t-butyl-4-hydroxy-5-methyl phenyl)propionyloxy]ethyl], 2,4,8,10-tetraoxaspiro[5,5]undecane, tetrakis-[methylene-3-(3′,5′-di-t-butyl-4′-hydroxy phenylpropionate)methane], 1,3,5-tris(3′,5′-di-t-butyl-4′-hydroxybenzyl)-sec-triazine-2,4,6-(1H,3H,5H ) aluminum salt of trione, para-methoxyphenol, 4-methoxy-1-naphthol, thiodiphenylamine, N-nitrosophenylhydroxyamine, trade name Adekastab LA-81, tradename Adekastab LA-82 (manufactured by Adeka Co., Ltd.), and the like. but not limited to these. Of these, naphthoquinone-based, hydroquinone-based, nitroso-based, and piperazine-based radical polymerization inhibitors are preferred, and naphthoquinone, 2-hydroxynaphthoquinone, hydroquinone, 2,6-di-tert-butyl-p-cresol, Polystop 7300P (Hakuto Co., Ltd.) is more preferred, and Polystop 7300P (manufactured by Hakuto Co., Ltd.) is most preferred.
The content of the radical polymerization inhibitor is preferably 0.0001 to 1% by mass, more preferably 0.001 to 0.5% by mass, more preferably 0.01 to 0.2%, based on the total amount of the display sealant of the present invention. % by weight is particularly preferred.

An example of the method for obtaining the sealant for display of the present invention includes the following method. First, components (A) and (B) are heated and dissolved. Then, after cooling to room temperature, components (C) and (D), inorganic fillers, silane coupling agents, antifoaming agents, leveling agents, solvents, etc. are added as necessary, and mixed with a known mixing device such as three rolls. , a sand mill, a ball mill, or the like, and filtered through a metal mesh to produce the display sealant of the present invention.

In addition, the display sealant of the present invention is very useful as an adhesive for liquid crystal display cells, particularly as a liquid crystal sealant. An example of a liquid crystal display cell in which the display sealant of the present invention is used as a liquid crystal sealant is shown below.

A liquid crystal display cell manufactured using the adhesive for a liquid crystal display cell of the present invention comprises a pair of substrates having predetermined electrodes formed on the substrates, arranged facing each other at a predetermined distance, and the periphery of the substrates being sealed with the liquid crystal sealing agent of the present invention. Liquid crystal is sealed in the gap between them. The type of liquid crystal to be enclosed is not particularly limited. Here, the substrate is composed of a combination of substrates, at least one of which is made of glass, quartz, plastic, silicon, or the like and has optical transparency. As a method for producing the liquid crystal sealing agent of the present invention, after adding a spacer (gap control material) such as glass fiber, the liquid crystal sealing agent is applied to one of the pair of substrates using a dispenser or a screen printer. After that, temporary curing is performed at 80 to 120° C., if necessary. After that, liquid crystal is dropped inside the weir of the liquid crystal sealant, and another glass substrate is overlapped in a vacuum to form 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 portion is irradiated with ultraviolet rays by an ultraviolet irradiator for photocuring. The UV irradiation dose is preferably 500 to 6000 mJ/cm ² , more preferably 1000 to 4000 mJ/cm ² (measurement wavelength: 365 nm). After that, 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 thus-obtained liquid crystal display cell of the present invention is free from defective display due to liquid crystal contamination and is excellent in adhesiveness and humidity resistance reliability. Examples of spacers include glass fibers, silica beads, polymer beads, and the like. Although the diameter varies depending on the purpose, it is usually 2-8 μm, preferably 4-7 μm. The amount used is usually 0.1 to 4 parts by mass, preferably 0.5 to 2 parts by mass, and more preferably about 0.9 to 1.5 parts by mass based on 100 parts by mass of the liquid crystal sealing agent of the present invention. be.

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

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the examples. Unless otherwise specified, "parts" and "%" in the text are based on mass.

The weight average molecular weight was measured by GPC (gel permeation chromatography) under the following conditions.
Model: TOSOH HLC-8320GPC (Tosoh)
Analysis column: TSKgel SuperMultipore HZ-M
Eluent: THF (tetrahydrofuran); 0.35 ml/min, temperature 40°C
Detector: Differential refractometer Molecular weight standard: Polystyrene

[Synthesis Example 1]
A flask equipped with a thermometer, a condenser, and a stirrer was charged with 351 of polyester polyol of 1,9-nonanediol, methyloctanediol, and adipic acid (O-1010 manufactured by Kuraray Co., Ltd., hydroxyl value: 113.5 mgKOH/g). 25 g, polyester polyol of methylpentanediol, adipic acid and isophthalic acid (P-1012 manufactured by Kuraray Co., Ltd., hydroxyl value 114.6 mg KOH / g) 347.88 g, toluene diisocyanate (Coronate T-100 manufactured by Tosoh Corporation, molecular weight 174.2) 197.99 g was charged and reacted at 80°C. The isocyanate content at this time was determined by adding excess amine and back titrating with hydrochloric acid, and confirmed that the value was within the range of plus or minus 2% of the residual amount of isocyanate obtained from the calculated value. Then, 0.6 g of methoquinone (polymerization inhibitor), 101.98 g of 2-hydroxyethyl acrylate (molecular weight: 116.1), and 0.3 g of dibutyltin dilaurate (catalyst) were added, stirred at 80°C, and infrared absorption spectrum was obtained. The reaction was carried out until the absorption spectrum (2280 cm ⁻¹ ) of the isocyanate group disappeared at , to obtain urethane acrylate (A) having a weight average molecular weight of 6900.

[Synthesis Example 2]
A flask equipped with a thermometer, a condenser, and a stirrer was charged with 352.06 g of polycaprolactone diol (PLAXEL 210 manufactured by Daicel Corporation, hydroxyl value: 113.1 mg KOH/g), a polyester of methylpentanediol, adipic acid, and isophthalic acid. Polyol (P-1012 manufactured by Kuraray Co., Ltd., hydroxyl value 114.6 mg KOH / g) 347.45 g and toluene diisocyanate (Coronate T-100 manufactured by Tosoh Corporation, molecular weight 174.2) 197.74 g were charged and reacted at 80 ° C. let me The isocyanate content at this time was determined by adding excess amine and back titrating with hydrochloric acid, and confirmed that the value was within the range of plus or minus 2% of the residual amount of isocyanate obtained from the calculated value. Then, 0.6 g of methoquinone (polymerization inhibitor), 101.85 g of 2-hydroxyethyl acrylate (molecular weight: 116.1), and 0.3 g of dibutyltin dilaurate (catalyst) were added, stirred at 80°C, and infrared absorption spectrum was obtained. The reaction was carried out until the absorption spectrum (2280 cm ⁻¹ ) of the isocyanate group disappeared at , to obtain urethane acrylate (B) having a weight average molecular weight of 5,200.

[Synthesis Example 3]
A flask equipped with a thermometer, a condenser, and a stirrer was charged with 776.99 g of a polyester polyol of methylpentanediol, adipic acid, and isophthalic acid (P-2012 manufactured by Kuraray Co., Ltd., hydroxyl value: 54.6 mg KOH/g) and toluene. 131.68 g of diisocyanate (Coronate T-100 manufactured by Tosoh Corporation, molecular weight 174.2) was charged and reacted at 80°C. The isocyanate content at this time was determined by adding excess amine and back titrating with hydrochloric acid, and confirmed that the value was within the range of plus or minus 2% of the residual amount of isocyanate obtained from the calculated value. Then, 0.6 g of methoquinone (polymerization inhibitor), 90.43 g of 2-hydroxyethyl acrylate (molecular weight: 116.1), and 0.3 g of dibutyltin dilaurate (catalyst) were added, stirred at 80°C, and infrared absorption spectrum was obtained. The reaction was carried out until the absorption spectrum (2280 cm ⁻¹ ) of the isocyanate group disappeared at , to obtain urethane acrylate (C) having a weight average molecular weight of 6300.

[Synthesis Example 4]
A flask equipped with a thermometer, a condenser, and a stirrer was charged with 620.4 g of a polyester polyol of methylpentanediol and sebacic acid (P-2050 manufactured by Kuraray Co., Ltd., hydroxyl value: 56.8 mg KOH/g) and tricyclodecane diol. 61.6 g of methanol (TCD alcohol DM manufactured by Celanese, molecular weight 196.3) and 196.9 g of toluene diisocyanate (Coronate T-100 manufactured by Tosoh Corporation, molecular weight 174.2) were charged and reacted at 80°C. The isocyanate content at this time was determined by adding excess amine and back titrating with hydrochloric acid, and confirmed that the value was within the range of plus or minus 2% of the residual amount of isocyanate obtained from the calculated value. Then, 0.9 g of methoquinone (polymerization inhibitor), 120.2 g of 2-hydroxyethyl acrylate (molecular weight: 116.1), and 0.5 g of dibutyltin dilaurate (catalyst) were added, stirred at 80°C, and infrared absorption spectrum was obtained. The reaction was carried out until the absorption spectrum (2280 cm ⁻¹ ) of the isocyanate group disappeared at , to obtain urethane acrylate (D) having a weight average molecular weight of 5780.

[Synthesis Example 5]
A flask equipped with a thermometer, a condenser, and a stirrer was charged with 724.7 g of a polyester polyol of methylpentanediol and sebacic acid (P-2050 manufactured by Kuraray Co., Ltd., hydroxyl value: 58.1 mg KOH/g), and tricyclodecane diol. 31.56 g of methanol (TCD alcohol DM manufactured by Celanese, molecular weight 196.3) and 178.73 g of isophorone diisocyanate (VESTANAT IPDI manufactured by Evonik, molecular weight 222.3) were charged and reacted at 80°C. The isocyanate content at this time was determined by adding excess amine and back titrating with hydrochloric acid, and confirmed that the value was within the range of plus or minus 2% of the residual amount of isocyanate obtained from the calculated value. Then, 0.6 g of methoquinone (polymerization inhibitor), 64.11 g of 2-hydroxyethyl acrylate (molecular weight: 116.1), and 0.3 g of dibutyltin dilaurate (catalyst) were added, stirred at 80°C, and infrared absorption spectrum was obtained. The reaction was carried out until the absorption spectrum (2280 cm ⁻¹ ) of the isocyanate group disappeared at , to obtain urethane acrylate (E) having a weight average molecular weight of 11,100.

[Synthesis Example 6]
A flask equipped with a thermometer, a condenser, and a stirrer was charged with polyester polyol (O-2010 manufactured by Kuraray Co., Ltd., hydroxyl value: 56.2 mgKOH/g) of 1,9-nonanediol, methyloctanediol, and adipic acid at 744. 2 g and 165.7 g of isophorone diisocyanate (VESTANAT IPDI manufactured by Evonik, molecular weight 222.3) were charged and reacted at 80°C. The isocyanate content at this time was determined by adding excess amine and back titrating with hydrochloric acid, and confirmed that the value was within the range of the residual amount of isocyanate determined from the calculated value plus or minus 2%. Then, 0.8 g of methoquinone (polymerization inhibitor), 89.2 g of 2-hydroxyethyl acrylate (molecular weight: 116.1), and 0.5 g of dibutyltin dilaurate (catalyst) were added, stirred at 80°C, and infrared absorption spectrum was obtained. The reaction was carried out until the absorption spectrum (2280 cm ⁻¹ ) of the isocyanate group disappeared at , to obtain urethane acrylate (F) having a weight average molecular weight of 10,630.

[Synthesis Example 7]
A flask equipped with a thermometer, a cooling tube and a stirrer was charged with 1979.2 g of polycaprolactone diol (PLAXEL 220 manufactured by Daicel Corporation, hydroxyl value 56.7 mg KOH/g) and isophorone diisocyanate (VESTANAT IPDI manufactured by Evonik, molecular weight 222. 3) 400.1 g was charged and reacted at 80°C. The isocyanate content at this time was determined by adding excess amine and back titrating with hydrochloric acid, and confirmed that the value was within the range of plus or minus 2% of the residual amount of isocyanate obtained from the calculated value. Next, 1.3 g of methoquinone (polymerization inhibitor), 191.4 g of 2-hydroxyethyl acrylate (molecular weight: 116.1), and 0.8 g of dibutyltin dilaurate (catalyst) were added, stirred at 80°C, and infrared absorption spectrum was obtained. The reaction was carried out until the absorption spectrum (2280 cm ⁻¹ ) of the isocyanate group disappeared at , to obtain urethane acrylate (G) having a weight average molecular weight of 11,070.

[Synthesis Example 8]
100 parts (0.28 mol) of commercially available benzopinacol (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 350 parts of dimethylformaldehyde. 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 were added thereto, and the mixture was heated 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 the product and deactivate the unreacted silylating agent. After separating the precipitated product by filtration, it was thoroughly washed with water. The resulting product was then dissolved in acetone and recrystallized by adding water for purification. 105.6 parts of the desired 1,2-bis(trimethylsiloxy)-1,1,2,2-tetraphenylethane was obtained (yield 88.3%).

[Examples 1 to 12, Comparative Examples 1 to 6]
Components (A), (B), and (O) were heated and dissolved at 90°C in the proportions shown in Table 1 below, then cooled to room temperature, components (C), (D), and (O) were added, After stirring, the mixture was dispersed with a three-roll mill and filtered through a metal mesh (635 mesh) to prepare a sealant for display.

[evaluation]
[Adhesion strength]
An alignment film solution (Nissan Chemical Co., Ltd.: NRB-U738) was spin-coated on a glass substrate, pre-baked on a hot plate at 80° C. for 3 minutes, and baked in an oven at 230° C. for 30 minutes. Further, the substrate with the alignment film was irradiated with ultraviolet rays of 500 mJ/cm ² (measurement wavelength: 254 nm) using a UV irradiation machine, and baked in an oven at 230° C. for 30 minutes.
1 g of glass fiber of 5 μm as a spacer is added to 100 g of the sealant for displays produced in Examples and Comparative Examples, and mixed and stirred. On the glass substrate coated with the alignment film, this sealant for display was coated so as to reproduce a corner portion of 1 cm x 1 cm, and the opposing alignment film ^- coated substrates were bonded together. After being irradiated with ultraviolet rays having a wavelength of 365 nm, the film was placed in an oven and thermally cured at 130° C. for 40 minutes. The peeling adhesion strength of the orientation film-coated glass substrate was measured with a bond tester (manufactured by Seishin Shoji Co., Ltd.: SS-30WD) by pressing the corner portion. Tables 1 and 2 show the results.

[Moisture Permeability]
The display sealants produced in Examples and Comparative Examples were sandwiched between polyethylene terephthalate (PET) films to form a thin film with a thickness of 300 μm, which was irradiated with ultraviolet rays of 3000 mJ/cm ² (measurement wavelength: 365 nm) using a UV irradiation machine. After that, it was placed in an oven and thermally cured at 130° C. for 40 minutes. After curing, the PET film was peeled off to obtain a sample. The moisture permeability of the sample at 60° C. 90% was measured with a moisture permeability meter (L80-5000 manufactured by Lessy). Tables 1 and 2 show the results.

[Elastic modulus]
The display sealants produced in Examples and Comparative Examples were sandwiched between polyethylene terephthalate (PET) films to form a thin film with a thickness of 100 μm, which was irradiated with ultraviolet rays of 3000 mJ/cm ² (measurement wavelength: 365 nm) using a UV irradiation machine. After that, it was placed in an oven and thermally cured at 130° C. for 40 minutes. After curing, the PET film was peeled off to obtain a sample. The tensile strength of the sample was measured using a Tensilon universal testing machine (RTG-1210, manufactured by A&D Co., Ltd.) at room temperature (25° C.) at a test speed of 5 mm/min. Tables 1 and 2 show the results.

[Storage stability]
The display sealants produced in Examples and Comparative Examples were weighed so that the mass in the syringe for dispensing was 2 g, and then subjected to defoaming treatment. ) was added 0.15 mL of the display sealant to the measuring cup. After leaving for 120 seconds as a preheat under conditions of a temperature of 25° C. and a cone of 3°×R7.7, the value was measured after 180 seconds at a rotational speed of 5 rpm. The initial viscosity a was measured. Then, after storage at 23° C. and 50% RH for 1 week, the viscosity b of the sealant for display was measured again. The increase rate of the viscosity b after one week with respect to the initial viscosity a was defined as (ba)/a. Viscosity stability was evaluated according to the following criteria. Tables 1 and 2 show the results.
○: viscosity increase rate is 1.3 times or less △: viscosity increase rate exceeds 1.3 times and 1.4 times or less ×: viscosity increase rate exceeds 1.4 times

From the results in Tables 1 and 2, it was confirmed that the display sealant of the present invention has both flexibility and low moisture permeability, and is also excellent in adhesive strength and storage stability.

The sealant for displays of the present invention has excellent adhesion strength to adherends and has both flexibility and low moisture permeability. It is useful as a sealant for shaped displays.

Claims (12)

A display sealant comprising (A) a curable compound and (B) a polymerization initiator, wherein the component (A) has an aromatic ring equivalent of 230 g/eq or more and 270 g/eq or less. 2. The sealant for display according to claim 1, wherein the (meth)acrylic equivalent of component (A) is 400 g/eq or more and 600 g/eq or less. 3. The sealant for displays according to claim 1, which contains urethane (meth)acrylate as the component (A). The display sealant according to claim 3, wherein the urethane (meth)acrylate contains a urethane (meth)acrylate obtained by reacting a polyol having an aromatic ring, an organic polyisocyanate, and a hydroxyl group-containing (meth)acrylate. . 5. The sealant for display according to claim 4, wherein the polyol having an aromatic ring comprises a polyol and a dibasic acid having an aromatic ring or an anhydride thereof. 6. The display sealant according to any one of claims 1 to 5, comprising a partial epoxy (meth)acrylate as the component (A). 7. The sealant for display according to any one of claims 1 to 6, further comprising component (C) an organic filler. 8. The display sealant according to claim 7, wherein the component (C) is one or more organic fillers selected from the group consisting of urethane fine particles, acrylic fine particles, styrene fine particles, styrene olefin fine particles, and silicone fine particles. . 9. The sealant for displays according to any one of claims 1 to 8, further comprising component (D) a thermosetting agent. 10. The sealant for a display according to any one of claims 1 to 9, which contains a radical photopolymerization initiator or a thermal radical polymerization initiator as the component (B). The display sealant according to any one of claims 1 to 10, which is a liquid crystal sealant for a liquid crystal dropping method. A liquid crystal display sealed with the liquid crystal sealant for liquid crystal dropping method according to claim 11 .