KR20160015207A - Sealing agent for display elements - Google Patents

Abstract

An object of the present invention is to provide a sealing agent for a display element which can inhibit the generation of outgas and is excellent in adhesiveness and transparency of a cured product. The present invention relates to a polythiol monomer having two or more thiol groups in one molecule, a polyene monomer having at least two carbon-carbon double bonds in one molecule, and a polyene monomer formed by the reaction of the polythiol monomer and the polyene monomer A polymerizable compound containing a thioether oligomer, and a polymerization initiator.

Description

[0001] SEALING AGENT FOR DISPLAY ELEMENTS [0002]

The present invention relates to a sealing agent for a display element which can inhibit the generation of outgas and has excellent adhesiveness and transparency of a cured product.

2. Description of the Related Art In recent years, liquid crystal display elements, organic EL display elements, and the like have been widely used as display elements having features such as thinness, light weight, and low power consumption. In these display elements, a photo-curable resin composition is usually used for sealing liquid crystal or a light-emitting layer.

In a liquid crystal display device, a transparent substrate on which two electrodes are formed is usually faced to each other with a predetermined gap therebetween, the periphery thereof is sealed with a sealing agent to form a cell, liquid crystal is injected into the cell from a liquid crystal injection hole formed in a part thereof And sealing the liquid crystal injection port using a sealant for a liquid crystal injection hole. Conventionally, curable epoxy resin compositions of one-component type or two-component type and photo-curable acrylic resin compositions as described in Patent Document 1 have been widely used as sealing agents for liquid crystal injection ports. However, since the one-component curable epoxy resin composition generally needs to be heated at a high temperature for a long time, the productivity is inferior and the two-component curable epoxy resin composition takes time to mix the main component and the curing agent, , And since it has to be used within the usable time (pot life) after mixing, the workability is particularly inferior. On the other hand, the acrylic resin composition of the photo-curable type is excellent in workability and productivity, but it has a strong interaction with the liquid crystal, so that the liquid crystal is contaminated to cause color unevenness, There has been a problem that outgas is generated, or adhesiveness or transparency of a cured product is inferior.

Further, in the organic EL display device, the performance of the organic light emitting material layer and the electrode is exposed to the outside air, and the performance thereof is rapidly deteriorated. Therefore, in order to improve the stability and durability of the organic EL display device, There has been proposed a method in which a resin film is covered and sealed with an inorganic material film interposed therebetween. For example, Patent Document 2 discloses a method of forming a resin film made of an acrylic resin composition on an inorganic material film. Patent Document 3 also discloses a method by photocathion polymerization. However, such a case also has a problem of generation of outgas by an acrylic resin.

Japanese Unexamined Patent Publication No. 6-160972 Japanese Laid-Open Patent Publication No. 2001-307873 Japanese Patent Application Laid-Open No. 2005-336314

It is an object of the present invention to provide a sealing agent for a display element which can inhibit the generation of outgas and is excellent in adhesiveness and transparency of a cured product.

The present invention relates to a polythiol monomer having at least two thiol groups in one molecule, a polyene monomer having at least two carbon-carbon double bonds in one molecule, and a thiol group formed by reaction of the polythiol monomer and the polyene monomer A polymerizable compound containing an ether oligomer, and a polymerization initiator.

Hereinafter, the present invention will be described in detail.

The present inventors have found that a polymerizable compound used in a sealant for a display device is a polythiol monomer having two or more thiol groups in one molecule, a polyene monomer having two or more carbon-carbon double bonds in one molecule, The use of a thioether oligomer formed by the reaction of a monomer and a polyene monomer to produce a sealing agent for a display element which can inhibit the generation of outgassing and which is excellent in adhesiveness and transparency of a cured product And have accomplished the present invention.

The sealing agent for a display element of the present invention can also prevent generation of liquid crystal contamination and damage to the organic light emitting material layer.

In the present specification, the "display element" refers to a liquid crystal display element and an organic EL display element.

The sealing agent for a display element of the present invention is a polymerizable compound which comprises a polythiol monomer having two or more thiol groups in one molecule (hereinafter, simply referred to as " polythiol monomer "), two or more carbon- (Hereinafter, simply referred to as " polyene monomer ") and a thioether oligomer (hereinafter also referred to simply as " thioether oligomer ") formed by the reaction of the polythiol monomer and the polyene monomer . The sealing agent for a display element of the present invention containing these components can suppress the generation of outgas, and exhibits excellent adhesive property and transparency of the cured product.

Examples of the polythiol monomer include aliphatic polythiols such as ethanedithiol, propanedithiol, hexamethylene dithiol and decamethylene dithiol; and aliphatic polythiols such as tolylene-2,4-dithiol, xylene dithiol, etc. Aromatic polythiols represented by the following formula (1) or polythiol compounds containing 1,4-dithiane rings represented by the following formula (1), ester bond-containing polythiol compounds, diglycol dimercaptane, Mercapto, tetraglycol dimercaptan, thiodiglycol dimercaptan, thiotriglycol dimercaptan, thiotetraglycol dimercaptan, tris- (3-mercaptopropionyloxy) -ethylisocyanurate, tetraethylene (3-mercaptopropionate), trimethylolpropane tris (3-mercaptopropionate), pentaerythritol-tetrakis (3-mercaptopropionate), dipentaerythritol-hexakis (3- (Mercaptomethyl) -3,6-dithiaoctane-1,8-dithiol, 4,8-bis (mercaptomethyl) -3,6,9-trithiaundecane 1,1-dithiol, 1,3,4,6-tetramercaptopropionyl glycoluril and the like, and the like. These polythiol monomers may be used alone or in combination of two or more.

[Chemical Formula 1]

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

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

Among the above-mentioned polythiol monomers, an ester bond-containing polythiol monomer is preferable because the resulting sealing material for a display element is excellent in transparency.

Specific examples of the ester bond-containing polythiol monomer include trimethylolpropane tris (3-mercaptopropionate), tris- [(3-mercaptopropionyloxy) -ethyl] -isocyanate Pentaerythritol tetrakisthioglycolate, pentaerythritol tetrakis (3-mercaptopropionate), tetraethylene glycol bis (3-mercaptopropionate), and the like.

Among them, trimethylolpropane tris (3-mercaptopropionate), pentaerythritol-tetrakis (3-mercaptopropionate), dipentaerythritol-hexakis (3-mercaptopropionate) Dithiane ring-containing polythiol compounds are preferable, and trimethylolpropane tris (3-mercaptopropionate), dipentaerythritol-hexakis (3-mercaptopropionate), 2,5- Dimercaptomethyl-1,4-dithiane are more preferable.

It is preferable that the polythiol monomer contains a monomer having three or more thiol groups in one molecule (trifunctional or higher polythiol monomer).

As the trifunctional or higher functional polythiol monomer, a monomer having 3 to 20 thiol groups in one molecule is preferable, and a monomer having 3 to 8 thiol groups in one molecule is more preferable.

The preferable lower limit of the content of the polythiol monomer in 100 parts by weight of the total polymerizable compound is 5 parts by weight, and the preferable upper limit is 40 parts by weight. If the content of the polythiol monomer is less than 5 parts by weight, the coating property may be deteriorated. If the content of the polythiol monomer exceeds 40 parts by weight, generation of outgas may not be sufficiently suppressed. A more preferable lower limit of the content of the polythiol monomer is 10 parts by weight, and a more preferable upper limit is 35 parts by weight.

Examples of the polyene monomer include (meth) allyl compounds, (meth) acrylic compounds, divinylbenzene, and the like. These polyene monomers may be used alone or in combination of two or more. In the present specification, the term "(meth) allyl" means allyl or methallyl, and the term "(meth) acryl" means acryl or methacryl.

Examples of the (meth) allyl compound include triallyl cyanurate, triallyl isocyanurate, trimethallyl isocyanurate, diallyl maleate, diallyl adipate, diallyl phthalate, triallyl Trimellitate, tetraallyl pyromellitate, glycerine diallyl ether, trimethylolpropane diallyl ether, pentaerythritol, diallyl ether, 1,3-diallyl-5-glycidylisocyanurate, 1,3 , 4,6-tetraallyl glycoluril, 1,3,4,6-tetraallyl-3a-methylglycoluril, 1,3,4,6-tetraallyl-3a, 6a-dimethylglycoluril and the like . Among them, triallyl cyanurate, triallyl isocyanurate and 1,3,4,6-tetraallyl glycoluril are preferable.

The (meth) acrylic compound is not particularly limited as long as it is a compound having two or more acryloyl groups or methacryloyl groups per molecule, and examples thereof include epoxy compounds obtained by reaction of (meth) acrylic acid with an epoxy compound (Meth) acrylate obtained by reacting a (meth) acrylic acid having a hydroxyl group with an ester compound obtained by reacting a (meth) acrylic acid with a compound having a hydroxyl group and an isocyanate with a (meth) acrylic acid derivative having a hydroxyl group.

In the present specification, the term "(meth) acrylate" means acrylate or methacrylate, and the term "epoxy (meth) acrylate" means that all epoxy groups in the epoxy compound are reacted with (meth) ≪ / RTI >

The epoxy (meth) acrylate is not particularly limited and includes, for example, those obtained by reacting (meth) acrylic acid and an epoxy compound in the presence of a basic catalyst according to a conventional method.

Examples of the epoxy compound to be a raw material of the epoxy (meth) acrylate include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol S type epoxy compounds, 2,2'-diallyl bisphenol A type epoxy compounds , Hydrogenated bisphenol type epoxy compounds, propylene oxide added bisphenol A type epoxy compounds, resorcinol type epoxy compounds, biphenyl type epoxy compounds, sulfide type epoxy compounds, diphenyl ether type epoxy compounds, dicyclopentadiene type epoxy compounds, A naphthalene type epoxy compound, a phenol novolak type epoxy compound, an orthocresol novolak type epoxy compound, a dicyclopentadiene novolak type epoxy compound, a biphenyl novolak type epoxy compound, a naphthalene phenol novolac type epoxy compound, glycidyl amine Type epoxy compound, alkyl polyol type epoxy compound, rubber modified epoxy There may be mentioned compounds, glycidyl ester compounds, bisphenol A-type episulfide compound.

Among the ester compounds obtained by reacting a compound having a hydroxyl group in (meth) acrylic acid, examples of the bifunctional compound include 1,4-butanediol di (meth) acrylate, 1,3-butanediol di (Meth) acrylate, 1,10-decanediol di (meth) acrylate, 2-n-butyl-2-ethyl Acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol (meth) acrylate, ethylene glycol di (meth) (Meth) acrylate, ethylene glycol di (meth) acrylate, propylene oxide adduct bisphenol A di (meth) acrylate, ethylene oxide adduct bisphenol A di Meth) acrylic Ethylene oxide adduct bisphenol F di (meth) acrylate, dimethylol dicyclopentadiene di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, neopentyl glycol di (meth) (Meth) acrylate, carbonate diol di (meth) acrylate, polyether diol di (meth) acrylate, polyether diol di Acrylate, polyester diol di (meth) acrylate, polycaprolactone diol di (meth) acrylate, and polybutadiene diol di (meth) acrylate.

Of the above ester compounds, examples of the trifunctional or more functional group include pentaerythritol tri (meth) acrylate, trimethylol propane tri (meth) acrylate, propylene oxide added trimethylol propane tri (meth) acrylate, (Meth) acrylates such as ethylene oxide adduct trimethylol propane tri (meth) acrylate, caprolactone modified trimethylol propane tri (meth) acrylate, ethylene oxide added isocyanuric acid tri (meth) acrylate, dipentaerythritol penta (Meth) acrylate, dipentaerythritol hexa (meth) acrylate, ditrimethylol propane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerin tri , Tris (meth) acryloyloxyethyl phosphate, and the like.

In addition, the polyene monomer preferably contains a monomer (trifunctional or higher functional polyene monomer) having at least three carbon-carbon double bonds in one molecule.

As the polyfunctional monomer having three or more functional groups, monomers having 3 to 20 carbon-carbon double bonds in one molecule are preferable, and monomers having 3 to 8 carbon-carbon double bonds in one molecule are more preferable.

The preferable lower limit of the content of the polyen monomer in the polymerizable compound is 100 parts by weight, and the preferable upper limit is 40 parts by weight. If the content of the polyene monomer is less than 5 parts by weight, the coating property may be deteriorated. If the content of the polyene monomer is more than 40 parts by weight, unreacted materials of the polyene monomer may generate residual gas. A more preferable lower limit of the content of the polyene monomer is 10 parts by weight, and a more preferable upper limit is 35 parts by weight.

The mixing ratio of the polythiol monomer to the polyene monomer is such that the molar ratio of the thiol group of the polythiol monomer to the carbon-carbon double bond of the polyene monomer ranges from 3: 1 to 1 : 3, and more preferably in a range of a thiol group: carbon-carbon double bond = 2: 1 to 1: 2.

The sealing agent for a display element of the present invention preferably contains, as the polymerizable compound, a polyene oligomer in addition to the polyene monomer. By containing the polyene oligomer, the effect of suppressing the generation of outgas and the coating ability can be improved.

In the present specification, the "polyene oligomer" is not included in the "polyene monomer".

Examples of the polyene monomer derived from the polyene oligomer include the (meth) allyl compound (meth) acrylic compound and divinylbenzene described above.

Examples of the method for producing the polyene oligomer include a method in which the polyene monomer is reacted in the presence of a polymerization initiator or the like to be described later. Examples of the polymerization initiator include a photopolymerization initiator and a thermal polymerization initiator, and a thermal polymerization initiator is preferably used.

The lower limit of the weight average molecular weight of the polyene oligomer is 300, and the upper limit is preferably 20,000. If the polyene oligomer has a weight average molecular weight of less than 300, the effect of suppressing the generation of outgas may not be sufficiently improved. If the polyene oligomer has a weight average molecular weight of more than 20,000, the viscosity of the resulting sealing agent for a display element may become too high and the coating property may be deteriorated. A more preferable lower limit of the weight average molecular weight of the polyene oligomer is 400, and a more preferable upper limit is 4000.

In the present specification, the " weight average molecular weight " is a value obtained by conducting gel permeation chromatography (GPC) and calculating by polystyrene conversion. As a column used for measuring the weight average molecular weight by polystyrene conversion by GPC, for example, Shodex LF-804 (manufactured by Showa Denko K.K.) can be used.

The preferable lower limit of the content of the polyenes oligomer is 30 parts by weight and the preferable upper limit is 90 parts by weight in 100 parts by weight of the total polymerizable compound. If the content of the polyene oligomer is less than 30 parts by weight, the effect of further suppressing the generation of outgas is not sufficiently exhibited. If the content of the polyene oligomer is more than 90 parts by weight, the resulting sealing agent for a display element may have an excessively high viscosity, resulting in deteriorated coating properties. A more preferable lower limit of the content of the thioether oligomer is 35 parts by weight, and a more preferable upper limit is 80 parts by weight.

Since the sealing agent for a display element of the present invention contains the thioether oligomer described above, the viscosity of the sealing agent for a display element is appropriately increased, and unevenness is hardly generated at the time of coating.

The thioether oligomer is subjected to addition polymerization reaction by light irradiation or heating in the presence of the polymerization initiator in the range of 3: 1 to 1: 3 relative to the polythiol monomer and the polythiol monomer Is obtained in the reaction mixture as a polymer. Examples of the polymerization initiator include a photopolymerization initiator and a thermal polymerization initiator, and a thermal polymerization initiator is preferably used. The thioether oligomer may contain an unreacted thiol group or an unreacted carbon-carbon double bond, and may not contain an unreacted thiol group or an unreacted carbon-carbon double bond. That is, it may be a thio group obtained by sufficiently conducting the addition polymerization reaction of the polythiol monomer and the polyene monomer, or a thioether oligomer not containing an unreacted carbon-carbon double bond, and terminating the reaction during the addition polymerization reaction Or a thioether oligomer containing an unreacted thiol group or an unreacted carbon-carbon double bond.

The thermal polymerization initiator is not particularly limited, but a thermal radical polymerization initiator is preferably used.

Examples of the thermal radical polymerization initiator include azo compounds, organic peroxides, and the like.

Examples of the azo compound include 2,2'-azobis (2,4-dimethylvaleronitrile), azobisisobutyronitrile, and the like.

Examples of the organic peroxide include benzoyl peroxide, ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, peroxy ester, diacyl peroxide, peroxydicarbonate, and the like.

As the photopolymerization initiator, the same photopolymerization initiator as the polymerization initiator contained in the encapsulating agent for a display element of the present invention to be described later can be used.

In the addition polymerization reaction of the polythiol monomer and the polyene monomer described above, the number of moles of the thiol group of the polythiol monomer (moles of the thiol group / carbon-carbon The number of moles of double bonds) is 0.15 or less, the polyene monomer usually remains as an unreacted component in the resulting reaction mixture.

The sealing agent for a display element of the present invention is characterized in that in the addition polymerization reaction of the polythiol monomer and the polyene monomer described above, the polythiol monomer obtained by stopping the reaction during the addition polymerization reaction, the polyene monomer and the thioether oligomer May contain a polymerization initiator.

The thioether oligomer may be mixed with a polythiol monomer and a polyene monomer in advance.

In the case where the thioether oligomer is prepared in advance, the polythiol monomer and the polyene monomer as raw materials of the thioether oligomer can be obtained by reacting the polythiol monomer and the polyene monomer contained in the sealing agent for a display element of the present invention It may be the same or different.

The preferred lower limit of the weight average molecular weight of the thioether oligomer is 500. When the weight average molecular weight of the thioether oligomer is less than 500, the effect of preventing unevenness during coating of the resulting sealing agent for a display element may not be sufficiently exhibited. The weight average molecular weight of the thioether oligomer is more preferably more than 1,500, and still more preferably 2,000 or more. The preferable upper limit of the weight average molecular weight of the thioether oligomer is 40,000. If the weight average molecular weight of the thioether oligomer exceeds 40,000, the viscosity of the resultant sealing agent for a display element becomes too high and the coating property becomes inferior.

A more preferable upper limit of the weight average molecular weight of the thioether oligomer is 10,000, and a more preferable upper limit is 8000.

The preferable lower limit of the content of the thioether oligomer in 100 parts by weight of the total polymerizable compound is 30 parts by weight. When the content of the thioether oligomer is less than 30 parts by weight, generation of outgas can not be sufficiently suppressed, or the effect of preventing unevenness during coating of the resulting sealing agent for a display element is not sufficiently exhibited. A more preferable lower limit of the content of the thioether oligomer is 35 parts by weight, and a more preferable lower limit is 40 parts by weight.

The preferable upper limit of the content of the thioether oligomer in 100 parts by weight of the total polymerizable compound is 90 parts by weight. If the content of the thioether oligomer exceeds 90 parts by weight, the viscosity of the resulting sealing agent for a display element may become too high and the coating property may deteriorate. A more preferable upper limit of the content of the thioether oligomer is 80 parts by weight.

The content of the polythiol monomer is 5 to 40% by weight, the content of the polyene monomer is 5 to 40% by weight, the content of the thioether oligomer is 30 to 90% by weight, . When the content of the polythiol monomer, the polyene monomer, and the thioether oligomer is within this range, the effect of suppressing the generation of outgas, the coating property, the adhesiveness, and the transparency of the cured product It can be exercised.

The sealing agent for a display element of the present invention may contain other polymerizable compounds other than the polythiol monomer, the polyene monomer, the polyene oligomer, and the thioether oligomer in the range of not hindering the object of the present invention .

The other polymerizable compound is not particularly limited as long as it is cured by light or heat, and examples thereof include an epoxy compound which is a raw material of the epoxy (meth) acrylate described above, a partial (meth) acrylic modified epoxy Compounds and the like.

In the present specification, the "partial (meth) acrylic modified epoxy compound" means a compound having at least one epoxy group and at least one (meth) acryloyl group in one molecule. In the present specification, the "(meth) acryloyl group" means an acryloyl group or a methacryloyl group.

The above-mentioned (meth) acryl-modified epoxy compound can be obtained, for example, by reacting one epoxy group of an epoxy compound having two or more epoxy groups in one molecule with (meth) acrylic acid.

The sealing agent for a display element of the present invention contains a polymerization initiator.

Examples of the polymerization initiator include a photopolymerization initiator and the above-described thermal polymerization initiator, and a photopolymerization initiator is preferably used.

The polymerization initiator preferably has a lower limit of molecular weight of 250 and a preferred upper limit of 1500. By using a polymerization initiator having a molecular weight of 250 to 1500, the sealing agent for a display element of the present invention is more excellent in suppressing the generation of outgas. If the molecular weight of the polymerization initiator is less than 250, outgas may be generated. If the molecular weight of the polymerization initiator is more than 1,500, the curing may be insufficient. Among them, a more preferable lower limit of the molecular weight of the polymerization initiator is 300, a more preferable upper limit is 1050, a more preferable lower limit is 348, and a more preferable upper limit is 790 from the viewpoint of reducing the generation of outgas.

As the photopolymerization initiator, for example, a compound having an acylphosphine oxide skeleton, a compound having an? -Aminoacetophenone skeleton, a compound having a benzylketal skeleton, a compound having an? -Hydroxyacetophenone skeleton, Compounds having a skeleton, compounds having an oxime ester skeleton, compounds having a titanocene skeleton, organic peroxides, azo compounds, oligomer compounds, and the like. These photopolymerization initiators may be used alone, or two or more of them may be used in combination. Among them, from the viewpoint of photocurability, a compound having an acylphosphine oxide skeleton, a compound having an? -Aminoacetophenone skeleton, a compound having a benzylketal skeleton, a compound having an? -Hydroxyacetophenone skeleton, a benzoin skeleton , A compound having an oxime ester skeleton, a compound having a titanocene skeleton, and an oligomer compound, and is preferably a compound having an acylphosphine oxide skeleton and / or an oligomer compound More preferable.

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 an? -Amino acetophenone skeleton means a compound in which a part of? -Amino acetophenone is substituted with another group. The compound having a benzylketal skeleton means a compound in which a part of the? -Hydroxyacetophenone is substituted with another group. The compound having an? -Hydroxyacetophenone skeleton means a compound in which a part other than the hydroxyl group of? -Monohydroxyacetophenone is substituted with another group. The compound having a benzoin skeleton means a compound in which a part of benzoin is substituted with another group. The compound having the oxime ester skeleton means a compound in which a part of N-acetyldimethyloxime is substituted with another group. The compound having the titanocene skeleton means a compound in which a part of the titanocene is substituted with another group. The above-mentioned 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 ("LUCILIN TPO", manufactured by BASF Japan), bis (2,4,6-trimethyl Benzoyl) phenylphosphine oxide ("IRGACURE 819", manufactured by BASF Japan).

Examples of the compound having an? -Aminoacetophenone skeleton include 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one (manufactured by BASF Japan, "IRGACURE 907 2-dimethylamino-1- (4-morpholinophenyl) butanone (IRGACURE 369, manufactured by BASF Japan) (Methylphenyl) methyl) -1- (4- (4-morpholinyl) phenyl) -1-butanone (IRGACURE 379, manufactured by BASF Japan).

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

As the compound having an? -Hydroxyacetophenone skeleton, for example, a compound having 2-hydroxy-1- (4- (4- (2-hydroxy-2-methyl-propionyl) 2-methyl-propan-1-one ("IRGACURE 127", manufactured by BASF Japan).

Examples of the compound having an oxime ester skeleton include 1- (4- (phenylthio) phenyl) -1,2-octanedione 2- (O-benzoyloxime) ("IRGACURE OXE 01 (IRGACURE OXE 02, manufactured by BASF Japan), and the like can be used. .

Examples of the compound having a titanocene skeleton include bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H- Yl) -phenyl) titanium ("IRGACURE 784" manufactured by BASF Japan).

The oligomer compound as the photopolymerization initiator preferably has a degree of polymerization of 2 to 10 from the viewpoint of reducing the generation of outgas, and it is preferable that the oligomer compound having a hydroxyl group-containing functional group such as a hydroxyl group or an amino group is .

Specifically, there may be mentioned, for example, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propane) ("ESACURE KIP 150", "ESACURE 1" (Omnipol 910, manufactured by IGM Co., Ltd.), (2-carboxymethyloxanthanthone) - ((2-dimethylamino- (Polyethylene glycol 250) diester (manufactured by IGM, " Omnipol BP "), and the like), and the like can be given as examples of the polytetramethyleneglycol 250) diester (Omnipol TX manufactured by IGM Corporation) and (carboxymethoxymethoxybenzophenone) have.

The content of the polymerization initiator is preferably 0.1 part by weight, and more preferably 5 parts by weight, based on 100 parts by weight of the polymerizable compound as a whole. If the content of the polymerization initiator is less than 0.1 parts by weight, the resulting curing reaction of the sealing agent for a display element may not sufficiently proceed. If the content of the polymerization initiator is more than 5 parts by weight, the curing reaction may be excessively accelerated and the workability may be deteriorated or the resulting cured product of the sealing agent for a display element may be uneven. A more preferable lower limit of the content of the polymerization initiator is 0.5 parts by weight, and a more preferable upper limit is 4 parts by weight.

The sealing agent for a display element of the present invention may contain a thermosetting agent.

The thermosetting agent is preferably a transparent cured product after curing, and examples thereof include thiol compounds, imidazole derivatives, amine compounds, polyhydric phenol compounds and acid anhydrides. Examples of commercially available thermosetting resins include HN-2200, HN-2000, HN-5500 and MHAC-P (all manufactured by Hitachi Chemical Co., Ltd.), Fuji Cure-7000, Fuji Cure- (All manufactured by T & K TOKA), MEH-8000H, MEH-8005 (all manufactured by Meiwa Chemical Industries, Ltd.) And the like.

The sealing agent for a display element of the present invention may contain an adhesive property-imparting agent.

Examples of the adhesion-imparting agent include 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, N- (aminoethyl) Silane coupling agents such as aminopropyltrimethoxysilane and mercaptopropyltrimethoxysilane, titanium coupling agents and aluminum coupling agents. These adhesiveness-imparting agents may be used alone, or two or more of them may be used in combination.

The sealing agent for a display element 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-t-butylphenol), 4,4'-butylidenebis- (6-t- Phenol), and 2,2'-methylenebis- (4-ethyl-6-t-butylphenol). These stabilizers may be used alone, or two or more of them may be used in combination.

The sealing agent for a display element of the present invention may further contain additives such as a filler, a curing accelerator, a plasticizer, a surfactant, a flame retardant, an antistatic agent, a defoaming agent, a leveling agent, an ultraviolet absorber, .

Examples of the method for producing a sealing agent for a display element of the present invention include a method of producing a sealing agent for a display element using a polythiol monomer, a polyenemonomer, a thioether oligomer, a polymerization initiator, and a polyenoligomer, , And a method of mixing uniformly using a stirrer.

The sealing agent for a display element of the present invention has a viscosity lower limit of 0.4 Pa · s and a preferable upper limit of 40 Pa · s as measured by a cone-type viscometer under the conditions of 20 ° C and 20 rpm. If the viscosity is less than 0.4 Pa s, the resulting sealing agent for a display element may be uneven in composition, may be difficult to apply, or the display characteristics of the resulting display element may deteriorate. If the viscosity exceeds 40 Pa · s, coating may become difficult. A more preferable lower limit of the viscosity is 0.5 Pa · s, a more preferable upper limit is 35 Pa · s, a more preferable lower limit is 1 Pa · s, and a more preferable upper limit is 25 Pa · s.

It is preferable that the sealing agent for a display element of the present invention has an average transmittance of visible light in a range of 380 to 780 nm of the cured product of 80% or more. Since the average transmittance of the visible light is 80% or more, it can be suitably used for applications requiring transparency. The average transmittance of the visible light is more preferably 95% or more.

The cured product for measuring the average transmittance of the visible light can be obtained by a method of irradiating the sealing agent for a display element of the present invention with ultraviolet light of 2000 mJ / cm 2.

It is preferable that the sealing agent for a display element of the present invention has a weight loss rate of 0.15% or less when the cured product having a thickness of 100 占 퐉 is heated to 130 占 폚 at a heating rate of 10 占 폚 / min. Since the weight reduction rate can be regarded as an outgassing amount, it is possible to suppress the adverse effect on the display element by 0.15% or less. The weight reduction rate is more preferably 0.1% or less.

The cured product for measuring the weight reduction rate can be obtained by a method of irradiating ultraviolet light of 2000 mJ / cm 2 to the sealing agent for a display element of the present invention which is applied so as to have a thickness of 100 탆.

Examples of the curing method for curing the sealing agent for a display element of the present invention by light irradiation include a method of irradiating light having a wavelength of 300 to 400 nm and an integrated amount of light of 300 to 3000 mJ / .

Examples of the light source for irradiating the sealing material for a display element of the present invention include a light source such as a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultra high pressure mercury lamp, an excimer laser, a chemical lamp, a black light lamp, A halide lamp, a sodium lamp, a halogen lamp, a xenon lamp, an LED lamp, a fluorescent lamp, a sunlight, and an electron beam irradiating device. These light sources may be used alone, or two or more of them may be used in combination.

Examples of the light irradiation means for the sealing material for a display element of the present invention include simultaneous irradiation of various light sources, sequential irradiation with a time difference, and combination irradiation of simultaneous irradiation and sequential irradiation. May be used.

The sealing agent for a display element of the present invention can be used as a sealing agent for sealing a surface, an entire surface, a front surface, a rear surface, or a periphery of a display element, a sealing agent, or a sealing agent for sealing an opening formed in the display element Among them, it is preferably used for sealing the entire surface of the display element.

In the present specification, the " whole surface " means not necessarily 100% of the surface having the display element, but means the necessary sealing surface required for the display element. The " front surface " means a surface on which light rays are extracted, that is, a surface on the viewer side.

The sealing agent for a display element of the present invention can be used as a sealing agent for an organic EL display element, a sealing agent for an organic EL display element, a sealing agent for a liquid crystal display element, a sealing agent for a liquid crystal display element, a sealing agent for an electrochromic substrate A sealing agent for an electrochromic substrate, a sealing agent for an electronic paper, a sealing agent for an electronic paper, and the like.

According to the present invention, it is possible to provide an encapsulant for a display element which can inhibit the generation of outgas, and has excellent adhesiveness and transparency of a cured product.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

(Preparation of thioether oligomer)

As shown in Table 1, a mixture of trimethylolpropane tris (3-mercaptopropionate) as a polythiol compound, triallyl isocyanurate as a polyene compound and 2,2'-azobis 2,4-dimethylvaleronitrile) were mixed in a mixing ratio shown in Table 1 using a stirrer ("Three One Motor HEIDON BLH300", manufactured by Shinto Scientific Co., Ltd.) to obtain a reaction mixture. The obtained reaction mixture was poured into a poor solvent, and the precipitated oligomers were collected and the solvent was removed under vacuum to obtain thioether oligomers AC.

The resulting thioether oligomers A to C were subjected to gel permeation chromatography (GPC) using Shodex LF-804 (manufactured by Showa Denko K.K.) as a column to determine the weight average molecular weight in terms of polystyrene. The results are shown in Table 1.

(Examples 1 to 11 and Comparative Examples 1 to 5)

The sealing materials for the display elements of Examples 1 to 11 and Comparative Examples 1 to 5 were prepared by mixing the respective materials according to the blending ratios shown in Tables 2 and 3 using a stirrer ("Three One Motor HEIDON BLH300" manufactured by Shinto Scientific Co., Ltd.) .

(evaluation)

The sealing agent for each display element obtained in Examples and Comparative Examples was evaluated by the following method. The results are shown in Tables 2 and 3.

(1) Viscosity

The viscosity of each sealing agent for display devices obtained in Examples and Comparative Examples was measured at 20 占 폚 and 20 rpm using a cone-shaped viscometer ("TV-22 type" manufactured by Toki Industries Co., Ltd.).

(2) Coating property

The applicability of the sealants for display devices obtained in Examples and Comparative Examples was evaluated on a glass substrate by using a dispenser (SHOTMASTER 300 manufactured by Musashi Engineering Co., Ltd.). When the dispenser nozzle was coated with 400 탆 of the nozzle gap, 30 탆 of the nozzle gap, and the discharge pressure of 300 고정, it was evaluated as "◯" when frictionless or sagging occurred, Quot ;, and " x " in the case where large application breakage or coating irregularity occurred or no application was possible at all.

(3) Outgassing amount

The sealants for display devices obtained in Examples and Comparative Examples were coated using a bar coater so that the thickness after coating was 100 mu m and ultraviolet rays of 2000 mJ / cm < 2 >

The resulting film was heated to 130 占 폚 at a heating rate of 10 占 폚 / min using a thermal analyzer ("TG / DTA6200" manufactured by Seiko Instruments Inc.), and the weight reduction rate was measured.

(4) Adhesiveness

0.05 g of the encapsulant for each display element obtained in Examples and Comparative Examples was applied to a glass substrate using a micropipette. The substrate was bonded to another glass substrate on which spacers were arranged so as to have a thickness of 50 mu m and irradiated with ultraviolet rays of 2000 mJ / cm < 2 > using a high-pressure mercury lamp. The obtained adhesive force test sample was subjected to a peeling test using EZ GRAPH (manufactured by Shimadzu Corporation) at a peeling rate of 5 mm / min to measure the adhesive force. , And those having an adhesive strength of 1.0 N / cm or more were evaluated as "? &Quot;, and those having an adhesive strength of less than 1.0 N / cm were rated "

(5) Transparency of the cured product (average transmittance of visible light)

The sealants for display elements obtained in Examples and Comparative Examples were sandwiched by PET resin films and irradiated with ultraviolet rays of 2000 mJ / cm 2 to prepare samples for measuring the transmittance of 100 탆 in thickness. The average transmittance of visible light at a wavelength of 380 to 780 nm was measured using a spectrophotometer ("U-3000", manufactured by Hitachi, Ltd. under the condition of 300 to 800 nm) for the obtained transmittance measurement sample.

(6) Display performance of the display element

(6-1) Display performance of liquid crystal display element

(Production of liquid crystal display element)

Two pieces of a glass substrate (length 25 mm, width 25 mm, and thickness 0.7 mm), in which an ITO electrode having a thickness of 1000 ANGSTROM was formed on the surface, and then an orientation film having a thickness of 800 ANGSTROM was applied on the surface by spin coating, A printing of a pattern in which a liquid crystal injection port portion was formed was performed by screen printing using a thermosetting epoxy resin (peripheral sealant). Next, the substrate on which the pattern was printed was maintained at 80 DEG C for 3 minutes to preliminarily dry and fuse the peripheral sealing agent to the substrate, and then returned to room temperature. Subsequently, a spacer of 5 mu m was scattered on the other substrate, each substrate was bonded to each other, and the peripheral sealing agent was cured by hot pressing at 130 DEG C for 2 hours to obtain an empty cell . (ZLI-4792, manufactured by Merck & Co., Inc.) was injected from the injection port, and the injection port was sealed using the sealant for each display element obtained in the examples and the comparative examples, and the high pressure mercury lamp Was irradiated with ultraviolet light of 3000 mJ / cm < 2 > to cure the sealant. Thereafter, liquid crystal annealing was performed at 120 占 폚 for 1 hour to produce a liquid crystal display element.

(Alignment disorder of liquid crystal display element)

The resulting liquid crystal display device was driven in a half-tone display state at a voltage of AC 3.5 V and the alignment disorder of the liquid crystal in the vicinity of the injection port was observed with a polarization microscope. Quot ;, "? &Quot;, "? &Quot;, "? &Quot;, " Was evaluated.

(6-2) Display performance of organic EL display device

(Production of a substrate on which a laminate including an organic light emitting material layer is disposed)

An ITO electrode having a thickness of 1000 angstroms was formed on a glass substrate (length 25 mm, width 25 mm, thickness 0.7 mm) as a substrate. The substrate was ultrasonically washed with acetone, an aqueous alkali solution, ion exchanged water and isopropyl alcohol for 15 minutes, and then washed with boiled isopropyl alcohol for 10 minutes. The substrate was again cleaned with a UV-ozone cleaner , &Quot; NL-UV253 ").

Next, this substrate was fixed to a substrate folder of a vacuum evaporation apparatus, 200 mg of N, N'-di (1-naphthyl) -N, N'-diphenylbenzidine (? -NPD) 200 mg of tris (8-hydroxyquinolinolato) aluminum (Alq ₃ ) was added to another unglazed crucible and the pressure in the vacuum chamber was reduced to 1 x 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 hole transporting layer having a film thickness of 600 Å. Subsequently, the crucible containing Alq ₃ was heated, and an organic light emitting material layer having a film thickness of 600 ANGSTROM was formed at a deposition rate of 15 ANGSTROM / s. Subsequently, the substrate on which the hole transporting layer and the organic light emitting material layer were formed was transferred to another vacuum vapor deposition apparatus, and 200 mg of lithium fluoride was charged into a resistance heating boat made of tungsten in the vacuum vapor deposition apparatus, and 1.0 g of aluminum wire was charged into another tungsten boat. Thereafter, the inside of the evaporator of the vacuum evaporation apparatus was reduced to 2 x 10 < ^-4 > Pa, lithium fluoride was formed in a thickness of 5 A at a deposition rate of 0.2 A / s, and then aluminum was deposited in a thickness of 1000 A at a rate of 20 A / s. The interior of the evaporator was returned to normal pressure with nitrogen, and a substrate on which a laminate including an organic light emitting material layer of 10 mm x 10 mm was placed was taken out.

(Coating with the inorganic material film A)

A mask having openings of 13 mm x 13 mm was provided on the substrate on which the laminate including the obtained organic light emitting material layer was disposed so as to cover the entire laminate, and the inorganic material film A was formed by the plasma CVD method.

In the plasma CVD method, SiH ₄ gas and nitrogen gas were used as source gases, and the flow rates were set to 10 sccm and 200 sccm, RF power was set to 10 W (frequency: 2.45 GHz), chamber temperature was set to 100 ° C, To 0.9 Torr.

The thickness of the inorganic material film A of the formed silicon nitride was about 0.2 탆.

(Formation of resin protective film)

A substrate on which a laminate coated with the inorganic material film A was disposed was placed in a vacuum apparatus and 0.5 g of each sealant for display elements obtained in Examples and Comparative Examples was placed in a heating boat provided in the vacuum apparatus and the pressure was reduced to 10 Pa , And the sealing material for a display element was heated at 200 占 폚 to a square portion of 11 mm 占 11 mm including the laminate to perform vacuum evaporation so as to have a thickness of 0.5 占 퐉. Thereafter, under a vacuum environment, a high-pressure mercury lamp was used to irradiate ultraviolet rays having a wavelength of 365 nm so as to have a dose of 3000 mJ / cm 2, and the sealing agent for a display element was cured to form a resin protective film.

(Coating with the inorganic material film B)

A mask having openings of 12 mm x 12 mm was provided so as to cover the entire resin protective film of 11 mm x 11 mm in the substrate on which the resin protective film was formed and an inorganic material film B was formed by the plasma CVD method, EL display element) was obtained.

In the plasma CVD method, SiH ₄ gas and nitrogen gas were used as source gases, and the flow rates thereof were set to 10 sccm of SiH ₄ gas and 200 sccm of nitrogen gas, RF power of 10 W (frequency of 2.45 GHz) Lt; 0 > C and a chamber pressure of 0.9 Torr.

The thickness of the inorganic material film B of the formed silicon nitride was about 1 mu m.

(Light emission state of the organic EL display element)

The organic EL display device thus manufactured was exposed for 100 hours under the conditions of 60 DEG C and 90% RH, and then a voltage of 3 V was applied to visually observe the light emitting state (light emission, dark spot, Quot ;, " DELTA " when a dark spot or peripheral extinction was recognized, and " x " when a non-light-emitting portion was remarkably enlarged, Was evaluated.

Industrial availability

According to the present invention, it is possible to provide an encapsulant for a display element which can inhibit the generation of outgas, and has excellent adhesiveness and transparency of a cured product.

Claims (11)

A polythiol monomer having two or more thiol groups in one molecule,
A polyene monomer having at least two carbon-carbon double bonds in one molecule, and
A polymerizable compound containing a thioether oligomer formed by the reaction of the polythiol monomer and the polyene monomer, and
A sealing agent for a display element, which comprises a polymerization initiator. The method according to claim 1,
Wherein the polythiol monomer contains a monomer having three or more thiol groups in one molecule. 3. The method according to claim 1 or 2,
Wherein the polyene monomer contains a monomer having at least three carbon-carbon double bonds in one molecule. The method according to claim 1, 2, or 3,
A sealant for a display element comprising a polyene oligomer. The method according to claim 1, 2, 3, or 4,
Wherein the thioether oligomer has a weight average molecular weight of 500 to 40,000. The method of claim 1, 2, 3, 4, or 5,
Wherein the content of the thioether oligomer in 100 parts by weight of the total polymerizable compound is 30 parts by weight or more. The method of claim 1, 2, 3, 4, 5, or 6,
Characterized in that the content of the polythiol monomer is 5 to 40% by weight, the content of the polyene monomer is 5 to 40% by weight, and the content of the thioether oligomer is 30 to 90% by weight in the whole of the sealing material for a display element By weight. The method of claim 1, 2, 3, 4, 5, 6, or 7,
Wherein the polymerization initiator has a molecular weight of from 250 to 1,500. The method of claim 1, 2, 3, 4, 5, 6, 7, or 8,
And a viscosity measured at 20 캜 and 20 rpm using a cone rotor viscometer is 0.4 to 40 Pa s. The method of claim 1, 2, 3, 4, 5, 6, 7, 8, or 9,
Wherein an average transmittance of visible light in a region of a wavelength of 380 to 780 nm of the cured product is 80% or more. The method according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10,
Wherein the cured product having a thickness of 100 占 퐉 is heated to 130 占 폚 at a heating rate of 10 占 폚 / min to have a weight reduction ratio of 0.15% or less.