JP2015218303A - Transparent sealant for display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent sealant for display elements which is excellent in transparency of its hardened product and reliability in high-temperature and high-humidity environments and can suppress adverse effects on the display performance due to generation of outgas.SOLUTION: A transparent sealant for display elements comprises at least one diene compound selected from compounds of specified formulae which has a cyclo ring and two unsaturated bonds bonded to both sides through an ester group, a polythiol compound having two or more thiol groups in one molecule and a photopolymerization initiator.

Description

The present invention relates to a transparent sealing agent for a display element that is excellent in transparency of a cured product and is reliable in a high-temperature and high-humidity environment and can suppress adverse effects on display performance due to outgassing.

In recent years, liquid crystal display elements, organic EL display elements, and the like are widely used as display elements having features such as thinness, light weight, and low power consumption. In these display elements, a photocurable resin composition is usually used for sealing a liquid crystal or a light emitting layer.

A liquid crystal display element usually has two transparent substrates with electrodes facing each other at a predetermined interval, and the periphery thereof is sealed with a sealant to form a cell, and a liquid crystal injection port provided in a part thereof Then, the liquid crystal is injected into the cell, and the liquid crystal inlet is sealed by using a liquid crystal inlet sealing agent. Conventionally, as a sealing agent for liquid crystal inlets, a one-component or two-component curable epoxy resin composition, a photocurable acrylic resin composition as described in Patent Document 1, and the like have been widely used. Has been used. However, the one-pack type curable epoxy resin composition generally requires a long period of heating at a high temperature, so the productivity is inferior. The two-pack type curable epoxy resin composition is a mixture of a main agent and a curing agent. It takes time and effort to do this, and after mixing, it must be used within the pot life (pot life). On the other hand, the photo-curable acrylic resin composition is excellent in workability and productivity, but because of its strong interaction with the liquid crystal, it contaminates the liquid crystal and causes color unevenness. There existed a problem that a large amount of outgas was generated by the remaining acrylic resin or the cured product was inferior in transparency.

In addition, in the organic EL display element, when the organic light emitting material layer and the electrode are exposed to the outside air, the performance of the organic EL display element deteriorates rapidly. Therefore, in order to increase the stability and durability of the organic EL display element, There has been proposed a method in which a material layer and an electrode are covered with a resin film via an inorganic material film and sealed. For example, Patent Document 2 discloses a method of forming a resin film made of an acrylic resin composition on an inorganic material film. However, even in such a case, there are problems such as outgas generation due to the acrylic resin.
Further, even when a material exhibiting excellent transparency at the time of manufacturing a display element, the transparency may be lowered when a reliability test is performed in a high temperature and high humidity environment.

JP-A-6-160972 JP 2001-307873 A

The present invention provides a transparent sealing agent for a display element, which is excellent in transparency of a cured product and reliability in a high-temperature and high-humidity environment, and can suppress adverse effects on display performance due to generation of outgas. The purpose is to do.

The present invention includes a compound represented by the following formula (1-1), a compound represented by the following formula (1-2), a compound represented by the following formula (1-3), and the following formula (1-4). And at least one diene compound selected from the group consisting of a compound represented by the following formula (1-5) and two or more thiol groups in one molecule: It is the transparent sealing agent for display elements containing the polythiol compound which has this, and a photoinitiator.

In formulas (1-1) to (1-5), X ¹ is an oxygen atom, a group represented by the following formula (2-1), or a group represented by the following formula (2-2). , X ² is an oxygen atom, a group represented by the following formula (3-1), or a group represented by the following formula (3-2). In formulas (1-1) to (1-3), Y represents an oxygen atom, a sulfur atom, a methylene group, or a secondary amino group. In formula (1-3), each Y may be the same or different.

The present invention is described in detail below.
The present inventor uses a specific diene compound in combination with a polythiol compound having two or more thiol groups in one molecule, thereby improving the transparency of the cured product and the reliability in a high-temperature and high-humidity environment. The present inventors have found that a transparent sealing agent for display elements can be obtained that is excellent and can suppress adverse effects on display performance due to outgassing and the like, and has completed the present invention.
In the present specification, the “display element” means a liquid crystal display element and an organic EL display element, and the “transparent” means an average transmission of visible light in a visible light region between wavelengths of 380 to 780 nm. It represents that the rate is 80% or more.

The transparent sealing agent for display elements of the present invention includes a compound represented by the above formula (1-1), a compound represented by the above formula (1-2), and a compound represented by the above formula (1-3). , At least one diene compound selected from the group consisting of a compound represented by the above formula (1-4) and a compound represented by the above formula (1-5) (hereinafter referred to as “ A diene compound according to the present invention). For example, when a polyene compound having an aromatic ring is used together with a polythiol compound having two or more thiol groups in one molecule (hereinafter also simply referred to as “polythiol compound”) as a photopolymerizable compound, Even if it is excellent in transparency, under a high temperature and high humidity environment, the rearrangement of the molecular structure derived from the polyene compound having an aromatic ring may cause the transparency to be easily lowered. On the other hand, when the diene compound according to the present invention is used, excellent transparency can be maintained without causing rearrangement of the molecular structure even in a high-temperature and high-humidity environment.

X ¹ and X ² in formulas (1-1) to (1-5), and Y in formulas (1-1) to (1-3) are less likely to cause outgas and reduce liquid crystal contamination. Is preferably an oxygen atom.

The transparent sealing agent for display elements of the present invention may contain other polyene compounds as long as the object of the present invention is not impaired. Hereinafter, the diene compound according to the present invention and the polyene compound are also simply referred to as “polyene compound”.
When the other polyene compound is contained, the diene compound according to the present invention in 100 parts by weight of the whole polyene compound is used from the viewpoint of transparency of the obtained sealant for display element and moisture resistance in a high temperature and high humidity environment. The minimum with preferable content is 20 weight part, and a more preferable minimum is 30 weight part.

Examples of the other polyene compounds include allyl alcohol derivatives, (meth) acrylic resins, and divinylbenzene. These polyene compounds may be used alone or in combination of two or more.
In the present specification, the “(meth) acryl” means acryl or methacryl.

Examples of the allyl alcohol derivatives include triallyl cyanurate, triallyl isocyanurate, diallyl maleate, diallyl adipate, diallyl phthalate, triallyl trimellitate, tetraallyl pyromellitate, glyceryl diallyl ether, trimethylolpropane diallyl ether. , Pentaerythritol, diallyl ether and the like. Of these, triallyl cyanurate and triallyl isocyanurate are more preferable.

The (meth) acrylic resin is not particularly limited as long as it is a resin having two or more methacryloyl groups or acryloyl groups in one molecule. For example, epoxy (meth) acrylic acid obtained by reaction of (meth) acrylic acid and epoxy resin ( (Meth) acrylate, ester compound obtained by reacting a compound having a hydroxyl group with (meth) acrylic acid, urethane (meth) acrylate obtained by reacting a (meth) acrylic acid derivative having a hydroxyl group with isocyanate, etc. It is done.
In the present specification, the “(meth) acrylate” means acrylate or methacrylate, and the “epoxy (meth) acrylate” means all epoxy groups in the epoxy resin and (meth) acrylic acid. It represents the reacted compound.

As said epoxy (meth) acrylate, what is obtained by making (meth) acrylic acid and an epoxy resin react with presence of a basic catalyst according to a conventional method is mentioned, for example.
Examples of the epoxy resin used as a raw material for the epoxy (meth) acrylate include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, 2,2′-diallyl bisphenol A type epoxy resin, and hydrogenated bisphenol. Type epoxy resin, propylene oxide-added bisphenol A type epoxy resin, resorcinol type epoxy resin, biphenyl type epoxy resin, sulfide type epoxy resin, diphenyl ether type epoxy resin, dicyclopentadiene type epoxy resin, naphthalene type epoxy resin, phenol novolac type epoxy resin , Orthocresol novolac epoxy resin, dicyclopentadiene novolac epoxy resin, biphenyl novolac epoxy resin, naphthalene phenol Examples include a borak type epoxy resin, a glycidyl amine type epoxy resin, an alkyl polyol type epoxy resin, a rubber-modified epoxy resin, a glycidyl ester compound, and a bisphenol A type episulfide resin.

Among the ester compounds obtained by reacting the (meth) acrylic acid with a compound having a hydroxyl group, examples of the bifunctional compound include 1,4-butanediol di (meth) acrylate and 1,3-butanediol. Di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, 2-n-butyl-2- Ethyl-1,3-propanediol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di ( (Meth) acrylate, tet Ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene oxide-added bisphenol A di (meth) acrylate, ethylene oxide-added bisphenol A di (meth) acrylate, ethylene oxide-added bisphenol F di (meth) acrylate, dimethylol di Cyclopentadiene didi (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethylene oxide modified isocyanuric acid di (meth) acrylate, 2-hydroxy-3- (meth) acryloyl Roxypropyl (meth) acrylate, carbonate diol di (meth) acrylate, polyether diol di (meth) acrylate, polyester diol (Meth) acrylate, polycaprolactone diol di (meth) acrylate, polybutadiene di (meth) acrylate.

Among the above ester compounds, those having three or more functional groups include, for example, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, propylene oxide-added trimethylolpropane tri (meth) acrylate, and ethylene oxide-added tri Methylolpropane tri (meth) acrylate, caprolactone-modified trimethylolpropane tri (meth) acrylate, ethylene oxide-added isocyanuric acid tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ditrimethylolpropane Tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerin tri (meth) acrylate, propylene N'okishido added glycerin tri (meth) acrylate, tris (meth) acryloyloxyethyl phosphate, and the like.

The other polyene compound preferably has 3 to 6 carbon-carbon double bonds in one molecule from the viewpoint of reactivity, and 4 to 6 carbon-carbon double bonds in one molecule. More preferably, it has a bond.

The content of the polyene compound is preferably 20 parts by weight with a preferred lower limit and 80 parts by weight with respect to a total of 100 parts by weight of the polyene compound and the polythiol compound. When the content of the polyene compound is less than 20 parts by weight, an unreacted product of the polythiol compound may remain and outgas may be generated. When the content of the polyene compound exceeds 80 parts by weight, unreacted polyene compound may remain and outgas may be generated. The minimum with more preferable content of the said polyene compound is 30 weight part, and a more preferable upper limit is 70 weight part.
The content of the polyene compound represents the content of the diene compound according to the present invention when the other polyene compound is not included, and the diene compound according to the present invention when the other polyene compound is included. And the total content of the other polyene compounds.

The transparent sealing agent for display elements of the present invention contains a polythiol compound.
Examples of the polythiol compound include aliphatic polythiols such as ethanedithiol, propanedithiol, hexamethylenedithiol and decamethylenedithiol, aromatic polythiols such as tolylene-2,4-dithiol and xylenedithiol, and the following formula (4) Cyclic sulfide compounds such as 1,4-dithiane ring-containing polythiol compounds, ester bond-containing polythiol compounds, diglycol dimercaptan, triglycol dimercaptan, tetraglycol dimercaptan, thiodiglycol dimercaptan, thiotri Glycol dimercaptan, thiotetraglycol dimercaptan, tris- (3-mercaptopropionyloxy) -ethyl isocyanurate, tetraethylene glycol-bis (3-mercaptopro Onnate), trimethylolpropane tris (3-mercaptopropionate), pentaerythritol-tetrakis (3-mercaptopropionate), dipentaerythritol-hexakis (3-mercaptopropionate), 4- (mercaptomethyl)- Examples include other polythiol compounds such as 3,6-dithiaoctane-1,8-dithiol and 4,8-bis (mercaptomethyl) -3,6,9-trithiaundecane-1,11-dithiol. These polythiol compounds may be used independently and may be used in combination of 2 or more type.

In formula (4), l represents an integer of 1 to 5.

Specific examples of the 1,4-dithiane ring-containing polythiol compound represented by the above formula (4) include 2,5-dimercaptomethyl-1,4-dithiane and 2,5-dimercaptoethyl-1 , 4-dithiane, 2,5-dimercaptopropyl-1,4-dithiane, 2,5-dimercaptobutyl-1,4-dithiane and the like.

Among the polythiol compounds, an ester bond-containing polythiol compound is preferable because the obtained transparent sealing agent for display elements is excellent in transparency.

Specific examples of the ester bond-containing polythiol compound include trimethylolpropane tris (3-mercaptopropionate), tris-[(3-mercaptopropionyloxy) -ethyl] -isocyanurate, pentaerythritol tetrakisthioglycol. Rate, pentaerythritol tetrakis (3-mercaptopropionate), tetraethylene glycol bis (3-mercaptopropionate), and the like.

Moreover, it is preferable that the said polythiol compound has 3-6 thiol groups in 1 molecule from a reactive viewpoint, and it is more preferable to have 4-6 thiol groups in 1 molecule.

As a blending ratio of the polyene compound and the polythiol compound, the molar ratio between the thiol group of the polythiol compound and the carbon-carbon double bond of the polyene compound is thiol group: carbon-carbon double bond = 1: 1. It is preferable to mix | blend in the range used as -1: 5, and it is more preferable to mix | blend in the range used as thiol group: carbon-carbon double bond = 1: 2-1: 4.

It is preferable that the transparent sealing agent for display elements of this invention contains the thioether oligomer formed by making the said polyene compound and the said polythiol compound react. By containing the thioether oligomer, the viscosity of the transparent sealing agent for display elements is appropriately increased, and unevenness is less likely to occur during coating.
In addition, when the thioether oligomer is contained, the content of the polyene compound, the total of the polyene compound and the polythiol compound, and the blending ratio of the polyene compound and the polythiol compound are determined based on the raw material of the thioether oligomer. It means what is included.

The thioether oligomer can be added to both ends by heating the polythiol compound and an equimolar amount or an excess amount of the polyene compound with respect to the polythiol compound in the presence of a thermal polymerization initiator to cause an addition polymerization reaction. It is obtained in the reaction mixture as a polymer having a carbon-carbon double bond of a polyene compound.
In addition, the said thioether oligomer may contain the unreacted thiol group, and does not need to contain the unreacted thiol group. That is, it may be a thioether oligomer containing no thiol group obtained by sufficiently proceeding an addition polymerization reaction between the polyene compound and the polythiol compound, or obtained by stopping the reaction in the middle of the addition polymerization reaction. It may be a thioether oligomer containing an unreacted thiol group.

The thermal polymerization initiator is not particularly limited, but a thermal radical polymerization initiator is preferably used.
As said thermal radical polymerization initiator, what consists of an azo compound, an organic peroxide, etc. is mentioned, for example.
Examples of the azo compound include 2,2′-azobis (2,4-dimethylvaleronitrile) and azobisisobutyronitrile.
Examples of the organic peroxide include benzoyl peroxide, ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, peroxyester, diacyl peroxide, and peroxydicarbonate.

In the addition polymerization reaction of the polythiol compound and the polyene compound described above, the number of moles of thiol group of the polythiol compound with respect to the number of moles of carbon-carbon double bond of the polyene compound (number of moles of thiol group / mol of carbon-carbon double bond). When the number) is 0.15 or less, the polyene compound usually remains as an unreacted component in the resulting reaction mixture.

The minimum with a preferable weight average molecular weight of the said thioether oligomer is 500, and a preferable upper limit is 40,000. When the weight average molecular weight of the thioether oligomer is less than 500, the effect of preventing unevenness during application of the obtained transparent sealing agent for display elements may not be sufficiently exhibited. When the weight average molecular weight of the thioether oligomer is more than 40,000, the obtained transparent sealing agent for display elements has a too high viscosity and is inferior in coatability. The minimum with a more preferable weight average molecular weight of the said thioether oligomer is 1000, and a more preferable upper limit is 10,000.
In the present specification, the “weight average molecular weight” is a value determined by polystyrene conversion after measurement by gel permeation chromatography (GPC). As a column used when measuring the weight average molecular weight by polystyrene conversion by GPC, Shodex LF-804 (made by Showa Denko KK) etc. are mentioned, for example.

The transparent sealing agent for display elements of the present invention may contain a curable resin other than the polyene compound and the polythiol compound as long as the object of the present invention is not impaired.
The curable resin is not particularly limited as long as it undergoes a curing reaction with light or heat, and examples thereof include an epoxy resin that is a raw material for the above-described epoxy (meth) acrylate, a partial (meth) acryl-modified epoxy resin, and the like. Can be mentioned.
In the present specification, the “partial (meth) acryl-modified epoxy resin” means a resin having one or more epoxy groups and one (meth) acryloyl group in one molecule. In the present specification, the “(meth) acryloyl group” means an acryloyl group or a methacryloyl group.
The partial (meth) acryl-modified epoxy resin can be obtained, for example, by reacting one epoxy group of an epoxy resin having two or more epoxy groups in one molecule with (meth) acrylic acid.

The transparent sealing agent for display elements of the present invention contains a photopolymerization initiator.
The above photopolymerization initiator has a preferred lower limit of molecular weight of 250 and a preferred upper limit of 1500. By using a photopolymerization initiator having a molecular weight of 250 to 1500, the transparent sealing agent for display elements of the present invention can further suppress outgassing. The more preferable lower limit of the molecular weight of the photopolymerization initiator is 300, the more preferable upper limit is 1050, the still more preferable lower limit is 348, and the still more preferable upper limit is 790.

Examples of the photopolymerization initiator include a compound having an acylphosphine oxide skeleton, a compound having an α-aminoacetophenone skeleton, a compound having a benzyl ketal skeleton, a compound having an α-hydroxyacetophenone skeleton, a compound having a benzoin skeleton, and an oxime. Examples thereof include a compound having an ester skeleton, a compound having a titanocene skeleton, an organic peroxide, an azo compound, and an oligomer compound. These photopolymerization initiators may be used alone or in combination of two or more. Among them, from the viewpoint of photocurability, a compound having an acylphosphine oxide skeleton, a heavy compound having an α-aminoacetophenone skeleton, a compound having a benzyl ketal skeleton, a compound having an α-hydroxyacetophenone skeleton, a compound having a benzoin skeleton, It is preferably at least one selected from the group consisting of a compound having an oxime ester skeleton, a compound having a titanocene skeleton, and an oligomer compound, and may be a compound having an acylphosphine oxide skeleton and / or an oligomer compound. More preferred.
Here, the compound having an acylphosphine oxide skeleton means a compound in which a part of the acylphosphine oxide is substituted with another group. The compound having the α-aminoacetophenone skeleton means a compound in which a part of α-aminoacetophenone is substituted with another group. The compound having the benzyl ketal skeleton means a compound in which a part of α-dihydroxyacetophenone is substituted with another group. The compound having the α-hydroxyacetophenone skeleton means a compound in which a part other than the hydroxyl group of α-monohydroxyacetophenone is substituted with another group. The compound having the benzoin skeleton means a compound in which a part of benzoin is substituted with another group. The compound having an oxime ester skeleton means a compound in which a part of N-acetyldimethyloxime is substituted with another group. The compound having a titanocene skeleton means a compound in which a part of titanocene is substituted with another group. The organic peroxide means a compound having a peroxy group. The azo compound means a compound having an azo group.

Examples of the compound having an acylphosphine oxide skeleton include 2,4,6-trimethylbenzoyldiphenylphosphine oxide (manufactured by BASF Japan, “LUCILIN TPO”), bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide. ("BASF Japan," IRGACURE 819 ").

Examples of the compound having an α-aminoacetophenone skeleton include 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one (manufactured by BASF Japan, “IRGACURE 907”), 2- Benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone (manufactured by BASF Japan, “IRGACURE 369”), 1,2- (dimethylamino) -2-((4-methylphenyl) methyl)- 1- (4- (4-morpholinyl) phenyl) -1-butanone (manufactured by BASF Japan, “IRGACURE 379”) and the like.

Examples of the compound having a benzyl ketal skeleton include 2,2-dimethoxy-1,2-diphenylethane-1-one (manufactured by BASF Japan, “IRGACURE 651”).

Examples of the compound having an α-hydroxyacetophenone skeleton include 2-hydroxy-1- (4- (4- (2-hydroxy-2-methyl-propionyl) -benzyl) phenyl) -2-methyl-propane-1 -ON (made by BASF Japan, "IRGACURE 127") and the like.

Examples of the compound having an oxime ester skeleton include 1- (4- (phenylthio) phenyl) -1,2-octanedione 2- (O-benzoyloxime) (manufactured by BASF Japan, “IRGACURE OXE 01”), O-acetyl-1- (6- (2-methylbenzoyl) -9-ethyl-9H-carbazol-3-yl) ethanone oxime (manufactured by BASF Japan, “IRGACURE OXE 02”) and the like.

Examples of the compound having a titanocene skeleton include bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium. (“BAGACURE 784” manufactured by BASF Japan) and the like.

The oligomer compound preferably has a degree of polymerization of 2 to 10 from the viewpoint of reducing outgas generation, and further has a hydroxyl-bonding functional group such as a hydroxyl group or an amino group because outgas is difficult to generate. Is preferred.
Specifically, for example, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propane) (manufactured by Lamberti, “ESACURE KIP 150”, “ESACURE1”), polyethylene glycol 200 -Di (β-4 (4- (2-dimethylamino-2-benzyl) butanonylphenyl) piperazine) (manufactured by IGM, “Omnipol 910”), (2-carboxymethoxythioxanthone)-(polytetramethylene glycol 250 ) Diester (IGM, “Omnipol TX”), (Carboxymethoxymethoxybenzophenone)-(polyethylene glycol 250) diester (IGM, “Omnipol BP”) and the like.

The content of the photopolymerization initiator is preferably 0.1 parts by weight with a preferred lower limit and 5 parts by weight with respect to a total of 100 parts by weight of the polyene compound and the polythiol compound. When the content of the photopolymerization initiator is less than 0.1 parts by weight, the photopolymerization of the obtained transparent sealing agent for display elements may not sufficiently proceed. When the content of the photopolymerization initiator exceeds 5 parts by weight, the curing reaction becomes too fast and the workability is deteriorated, or the cured product of the obtained transparent sealing agent for display elements is not uniform. Sometimes. The minimum with more preferable content of the said photoinitiator is 0.3 weight part, and a more preferable upper limit is 3 weight part.

The transparent sealing agent for display elements of the present invention may contain a thermosetting agent.
The thermosetting agent preferably has a cured product that is transparent, and examples thereof include thiol compounds, imidazole derivatives, amine compounds, polyhydric phenol compounds, and acid anhydrides. Examples of commercially available thermosetting agents include HN-2200, HN-2000, HN-5500, MHAC-P (manufactured by Hitachi Chemical Co., Ltd.), Fuji Cure 7000, Fuji Cure 7001, Fuji Cure 7002, and Tomide. 410-N, tomide 215-70X, tomide 423, tomide 437, tomide TXC-636-A (above, manufactured by T & K TOKA), MEH-8000H, MEH-8005 (above, manufactured by Meiwa Kasei) and the like.

The transparent sealing agent for display elements of the present invention may contain an adhesion promoter.
Examples of the adhesion-imparting agent include 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and N- (aminoethyl) aminopropyltrimethoxy. Examples include silane coupling agents such as silane and mercaptopropyltrimethoxysilane, titanium coupling agents, and aluminum coupling agents. These adhesiveness imparting agents may be used alone or in combination of two or more.

The transparent sealing agent for display elements of the present invention may contain a stabilizer for the purpose of preventing oxidation or the like.
Examples of the stabilizer include 2,2′-methylenebis- (4-methyl-6-tert-butylphenol), 4,4′-butylidenebis- (6-tert-butyl-3-methylphenol), 2,2 '-Methylenebis- (4-ethyl-6-t-butylphenol) and the like. These stabilizers may be used independently and 2 or more types may be used together.

The transparent sealing agent for display elements of the present invention further includes the above thermal polymerization initiator, filler, curing accelerator, plasticizer, surfactant, flame retardant, and antistatic agent within the range not impairing the object of the present invention. Further, additives such as an antifoaming agent, a leveling agent, an ultraviolet absorber, and an organic solvent may be contained.

Examples of the method for producing the transparent sealing agent for display elements of the present invention include, for example, a polythiol compound, a polyene compound, a photopolymerization initiator, a thermal polymerization initiator, and an adhesion imparting agent added as necessary. And the like are mixed uniformly using a stirrer.

The minimum with a preferable glass transition temperature of the transparent sealing agent for display elements of this invention is 80 degreeC. When the glass transition temperature is less than 80 ° C., the obtained cured product may be inferior in reliability under a high temperature and high humidity environment. A more preferable lower limit of the glass transition temperature is 85 ° C.
In addition, the said glass transition temperature shows the tan-delta peak temperature value which can be measured on conditions with a temperature increase rate of 5 degree-C / min and a frequency of 10 Hz by DMA method.

The transparent sealing agent for display elements of the present invention has a preferred lower limit of 0.4 Pa · s and a preferred upper limit of 40 Pa · s, measured using a cone rotor viscometer under the conditions of 20 ° C. and 20 rpm. When the viscosity is less than 0.4 Pa · s, compositional unevenness occurs in the obtained transparent sealing agent for display elements, coating becomes difficult, display characteristics of the obtained display elements are deteriorated, There are things to do. When the viscosity exceeds 40 Pa · s, coating may be difficult. The more preferable lower limit of the viscosity is 0.5 Pa · s, the more preferable upper limit is 35 Pa · s, the still more preferable lower limit is 1 Pa · s, and the still more preferable upper limit is 25 Pa · s.

The transparent sealing agent for display elements of the present invention can be cured by light irradiation.
Examples of the method of photocuring the transparent sealing agent for display elements of the present invention include a method of irradiating light with a wavelength of 300 to 400 nm and an integrated light amount of 300 to 3000 mJ / cm ² .

Examples of the light source for irradiating the transparent sealing agent for display elements of the present invention with light include a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, an excimer laser, a chemical lamp, a black light lamp, and a microwave excitation. Examples include mercury lamps, metal halide lamps, sodium lamps, halogen lamps, xenon lamps, LED lamps, fluorescent lamps, sunlight, and electron beam irradiation devices. These light sources may be used independently and 2 or more types may be used together.

Examples of the light irradiation means for the transparent sealing agent for display elements of the present invention include simultaneous irradiation of various light sources, sequential irradiation with a time difference, combined irradiation of simultaneous irradiation and sequential irradiation, etc. The irradiation means may be used.

ADVANTAGE OF THE INVENTION According to this invention, it is excellent in transparency of hardened | cured material and the reliability in a high temperature, high humidity environment, and can suppress the bad influence on display performance by generation | occurrence | production of outgas etc., and the transparent sealing agent for display elements. Can be provided.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

(Production of a compound represented by the formula (1-4) (X ¹ and X ² are oxygen atoms))
Solution adjustment of 100 parts by weight of decahydro-2,7-naphthalenediol (Sugai Chemical Co., Ltd.) and 50 parts by weight of methyl vinyl ether in N, N-dimethylformamide in the presence of a palladium catalyst did. The obtained N, N-dimethylformamide solution was reacted at 80 ° C. for 5 hours under an argon atmosphere to obtain a compound in which X ¹ and X ² in formula (1-4) are oxygen atoms.

(Production of compound represented by formula (1-5) (X ¹ and X ² are oxygen atoms))
100 parts by weight of dihydroxy-4,7-methanohydrindane and 50 parts by weight of methyl vinyl ether were adjusted to 10% by weight in N, N-dimethylformamide in the presence of a palladium catalyst. The obtained N, N-dimethylformamide solution was reacted at 80 ° C. for 5 hours under an argon atmosphere to obtain a compound in which X ¹ and X ² in formula (1-5) are oxygen atoms.

(Examples 1-7, Comparative Example 1)
According to the blending ratio described in Table 1, each material was heated and mixed at 70 ° C. for 3 hours using a stirrer (manufactured by Shinto Kagaku Co., Ltd., “Three-One Motor HEIDON BLH300”). And the transparent sealing agent for display elements of the comparative example 1 was prepared.

<Evaluation>
About each transparent sealing agent for display elements obtained by the Example and the comparative example, it evaluated by the following method. The results are shown in Table 1.

(1) Transparency of cured product Each transparent sealing agent for display elements obtained in Examples and Comparative Examples is sandwiched between PET resin films, irradiated with 2000 mJ / cm ² ultraviolet rays, and has a transmittance of 50 μm in thickness. A measurement sample was prepared. About the obtained sample for transmittance | permeability, the light transmittance in wavelength 380-780 nm was measured using the spectrophotometer (The Hitachi, Ltd. make, "U-3000", conditions 300-800 nm). “◎” indicates that the average transmittance at a wavelength of 380 to 780 nm is 95% or more, “◯” indicates that the average transmittance is 90% or more and less than 95%, and “△” indicates that the transmittance is 80% or more and less than 90%. The transparency of the cured product was evaluated with “x” being less than 80%.

(2) Reliability under high-temperature and high-humidity environment A sample for measuring transmittance was prepared in the same manner as in the above “(1) Transparency of cured product”. The obtained transmittance measurement sample was stored for 1 week in an environment of 85 ° C. and 85% RH, and then used with a spectrophotometer (manufactured by Hitachi, Ltd., “U-3000”, conditions 300 to 800 nm). The light transmittance at a wavelength of 380 to 780 nm was measured. “◎” indicates that the average transmittance at a wavelength of 380 to 780 nm is 95% or more, “◯” indicates that the average transmittance is 90% or more and less than 95%, and “△” indicates that the transmittance is 80% or more and less than 90% In addition, the reliability under a high temperature and high humidity environment was evaluated as “x” when less than 80%.

(3) Display performance of display element (3-1) Display performance of liquid crystal display element (production of liquid crystal display element)
Prepare two glass substrates (length 25mm, width 25mm, thickness 0.7mm) on which an ITO electrode with a thickness of 1000mm is formed on the surface and then an orientation film with a thickness of 800mm is applied on the surface by spin coating. Then, using a thermosetting epoxy resin (peripheral sealant) on one substrate, printing of a pattern in which a liquid crystal injection port was provided was performed by screen printing. Next, the substrate on which the pattern was printed was kept at 80 ° C. for 3 minutes to perform preliminary drying and fusion of the peripheral sealant to the substrate, and then returned to room temperature. Next, after spraying a spacer of 5 μm on the other substrate, the substrates are bonded together, and the peripheral sealant is cured for 2 hours with a hot press heated to 130 ° C. to cure the empty liquid crystal display element. Obtained. The obtained empty liquid crystal display element was vacuum-sucked, and then liquid crystal (Merck, “ZLI-4792”) was injected from the injection port. The injection port was transparent for each display element obtained in Examples and Comparative Examples. Sealing was performed using a sealing agent, and the sealing agent was cured by irradiating ultraviolet rays of 2000 mJ / cm ² using an LED lamp having a wavelength of 365 nm. Thereafter, the liquid crystal was annealed at 120 ° C. for 1 hour to produce a liquid crystal display element.

(Liquid crystal orientation disorder)
The obtained liquid crystal display element was driven in a halftone display state at a voltage of AC 3.5 V, and the alignment disorder of the liquid crystal near the inlet was observed with a polarizing microscope. The case where no alignment disorder is confirmed is indicated by “◯”, the case where an alignment disorder less than 1 mm is confirmed is “Δ”, and the case where there is a clear alignment disorder (dark color unevenness) of 1 mm or more is indicated by “X”. The display performance of the liquid crystal display element was evaluated.

(3-2) Display performance of organic EL display element (production of a substrate on which a laminate including an organic light emitting material layer is disposed)
A glass substrate (length 25 mm, width 25 mm, thickness 0.7 mm) on which an ITO electrode was formed to a thickness of 1000 mm was used as the substrate. The substrate was ultrasonically washed with acetone, an aqueous alkali solution, ion-exchanged water, and isopropyl alcohol for 15 minutes each, then washed with boiled isopropyl alcohol for 10 minutes, and further UV-ozone cleaner (manufactured by Nippon Laser Electronics Co., Ltd., The last treatment was performed with “NL-UV253”).
Next, this substrate is fixed to the substrate folder of the vacuum deposition apparatus, and 200 mg of N, N′-di (1-naphthyl) -N, N′-diphenylbenzidine (α-NPD) is put into an unglazed crucible in other different ways. 200 mg of tris (8-hydroxyquinola) aluminum (Alq ₃ ) was put in an unglazed crucible, and the pressure in the vacuum chamber was reduced to 1 × 10 ⁻⁴ Pa. Thereafter, the crucible containing α-NPD was heated and α-NPD was deposited on the substrate at a deposition rate of 15 Å / s to form a 600 正 孔 hole transport layer. Next, the crucible containing Alq ₃ was heated to form an organic light emitting material layer having a thickness of 600 で at a deposition rate of 15 Å / s. Thereafter, the substrate on which the hole transport layer and the organic light emitting material layer are formed is transferred to another vacuum vapor deposition apparatus, and 200 mg of lithium fluoride is added to a tungsten resistance heating boat in the vacuum vapor deposition apparatus, and aluminum is added to another tungsten boat. 1.0 g of wire was added. Then, after reducing the pressure in the vapor deposition unit of the vacuum vapor deposition apparatus to 2 × 10 ⁻⁴ Pa and depositing 5 μm of lithium fluoride at a deposition rate of 0.2 kg / s, deposit 1000 μm of aluminum at a rate of 20 kg / s. did. The inside of the vapor deposition apparatus was returned to normal pressure with nitrogen, and the substrate on which the laminate including the organic light emitting material layer of 10 mm × 10 mm was arranged was taken out.

(Coating with inorganic material film A)
A mask having an opening of 13 mm × 13 mm is installed so as to cover the entire laminate of the substrate on which the laminate including the obtained organic light emitting material layer is disposed, and the inorganic material film A is formed by plasma CVD. Formed.
In the plasma CVD method, SiH ₄ gas and nitrogen gas are used as source gases, the flow rates are 10 sccm and 200 sccm, RF power is 10 W (frequency: 2.45 GHz), chamber temperature is 100 ° C., and chamber pressure is 0. The test was performed at 9 Torr.
The thickness of the formed inorganic material film A of silicon nitride was about 0.2 μm.

(Formation of resin protective film)
A substrate on which a laminate coated with the inorganic material film A is placed in a vacuum device, and a transparent for display element obtained in each of the examples and comparative examples is provided on a heating boat installed in the vacuum device. 0.5 g of the sealing agent was added, the pressure was reduced to 10 Pa, and the transparent sealing agent for display element was heated at 200 ° C. to a 11 mm × 11 mm square portion including the laminate, so that the thickness became 0.5 μm. Vacuum vapor deposition was performed. After that, using a high pressure mercury lamp in a vacuum environment and using an LED lamp with a wavelength of 365 nm, light is irradiated so that the integrated light quantity becomes 2000 mJ / cm ^2, and the transparent sealing agent for display elements is cured to protect the resin. A film was formed.

(Coating with inorganic material film B)
A mask having an opening of 12 mm × 12 mm is installed so as to cover the entire 11 mm × 11 mm resin protective film of the substrate on which the resin protective film is formed, and an inorganic material film B is formed by plasma CVD and displayed. An element (organic EL display element) was obtained.
In the plasma CVD method, SiH ₄ gas and nitrogen gas are used as source gases, the flow rates of each are SiH ₄ gas 10 sccm, nitrogen gas 200 sccm, RF power 10 W (frequency 2.45 GHz), chamber temperature 100 ° C., chamber The test was performed under the condition that the internal pressure was 0.9 Torr.
The thickness of the formed inorganic material film B of silicon nitride was about 1 μm.

(Light emission state of organic EL display element)
The produced organic EL display element was exposed for 100 hours under conditions of 60 ° C. and 90% RH, respectively, a voltage of 3 V was applied, and the light emission state (dark spot, presence / absence of pixel peripheral extinction) was visually observed, and dark Display of organic EL display elements as “○” when there is no spot or peripheral extinction, “△” when dark spot or peripheral extinction is recognized, and “×” when non-light-emitting area is significantly enlarged Performance was evaluated.

ADVANTAGE OF THE INVENTION According to this invention, it is excellent in transparency of hardened | cured material and the reliability in a high temperature, high humidity environment, and can suppress the bad influence on display performance by generation | occurrence | production of outgas etc., and the transparent sealing agent for display elements. Can be provided.

Claims (2)

The compound represented by the following formula (1-1), the compound represented by the following formula (1-2), the compound represented by the following formula (1-3), and the following formula (1-4) A polythiol compound having at least one diene compound selected from the group consisting of a compound and a compound represented by the compound represented by the following formula (1-5), and two or more thiol groups in one molecule And a photopolymerization initiator. A transparent sealing agent for display elements, comprising:

In formulas (1-1) to (1-5), X ¹ is an oxygen atom, a group represented by the following formula (2-1), or a group represented by the following formula (2-2). , X ² is an oxygen atom, a group represented by the following formula (3-1), or a group represented by the following formula (3-2). In formulas (1-1) to (1-3), Y represents an oxygen atom, a sulfur atom, a methylene group, or a secondary amino group. In formula (1-3), each Y may be the same or different.

The transparent sealing agent for display elements according to claim 1, comprising a thioether oligomer.