TWI834647B - Sealant for organic EL display elements - Google Patents

Abstract

An object of the present invention is to provide a sealant for organic EL display elements that is excellent in coating properties for substrates or inorganic material films even when thinned. The present invention is a sealant for organic EL display elements, which contains a curable resin and a polymerization initiator, and has a surface tension of 25 mN/m or more and 38 mN/m or less at 25°C, and the above-mentioned sealant for organic EL display elements is The contact angles between the agent and the SiO ₂ substrate and the SiN substrate at 25°C are both below 13 degrees; the surface free energy of the above-mentioned SiO ₂ substrate is above 70 mN/m and below 80 mN/m, and the surface free energy of the above-mentioned SiN substrate is 50 mN/m or more and 60 mN/m or less.

Description

Sealant for organic EL display elements

The present invention relates to a sealant for organic EL display elements that has excellent coating properties on a substrate or an inorganic material film even when it is thinned.

Organic electroluminescence (hereinafter also referred to as "organic EL") display elements have a laminated body structure in which an organic light-emitting material layer is sandwiched between opposing electrodes, and electrons are injected from one electrode into the organic Positive holes are injected into the organic light-emitting material layer from another electrode, so that electrons and positive holes are combined in the organic light-emitting material layer to emit light. Since organic EL display elements self-emit in this manner, compared with liquid crystal display elements that require a backlight, they have the following advantages: they have better visibility, can be made thinner, and can be driven by DC low voltage.

There is a problem that the organic light-emitting material layer or electrode constituting the organic EL display element is easily deteriorated by moisture, oxygen, etc. Therefore, in order to obtain a practical organic EL display element, the organic light-emitting material layer or electrode must be isolated from the atmosphere to achieve a long life. Patent Document 1 discloses a method of sealing an organic light-emitting material layer and an electrode of an organic EL display element with a laminated film of a silicon nitride film and a resin film formed by a CVD method. Here, the resin film has the function of preventing the internal stress of the silicon nitride film from compressing the organic layer or electrode.

As a method for preventing moisture from penetrating into the organic light-emitting material layer, Patent Document 2 discloses a method of alternately evaporating an inorganic material film and a resin film, and Patent Document 3 and Patent Document 4 disclose a method of depositing an inorganic material film Method for forming a resin film on. Prior technical literature patent documents

Patent Document 1: Japanese Patent Application Publication No. 2000-223264 Patent Document 2: Japanese Patent Publication No. 2005-522891 Patent Document 3: Japanese Patent Application Publication No. 2001-307873 Patent Document 4: Japanese Patent Application Publication No. 2008-149710

[Problem to be solved by the invention]

As a method of forming a resin film, there is a method of applying a sealant on a base material using an inkjet method and then hardening the sealant. If this coating method using the inkjet method is used, a resin film can be formed uniformly at high speed. On the other hand, organic EL display elements are required to be flexible for use by being curved or folded. Therefore, it is necessary to make the sealant for organic EL display elements also flexible. As one of the methods for making the sealant for organic EL display elements flexible, it is considered to make the sealant thin. However, the conventional sealant has the following problem: coatability when thinning by inkjet method or the like. If it is poor, pinholes will be generated, resulting in poor reliability of the obtained organic EL display element. An object of the present invention is to provide a sealant for organic EL display elements that is excellent in coating properties for substrates or inorganic material films even when thinned. [Technical means to solve the problem]

The present invention 1 is a sealant for organic EL display elements, which contains a curable resin and a polymerization initiator, has a surface tension of 25 mN/m or more and 38 mN/m or less at 25°C, and is used for organic EL display elements. The contact angles between the sealant and the SiO ₂ substrate and the SiN substrate at 25°C are both below 13 degrees; the surface free energy of the SiO ₂ substrate is above 70 mN/m and below 80 mN/m, and the surface free energy of the SiN substrate is below 13 degrees. 50 mN/m or more and 60 mN/m or less. In addition, the present invention 2 is a sealant for organic EL display elements, which is used for coating by the inkjet method, and contains a curable resin and a polymerization initiator, and has a surface tension of 25 mN/m at 25°C. Above and below 38 mN/m, and the contact angles between the above-mentioned sealant for organic EL display elements and the SiO ₂ substrate and SiN substrate at 25°C are both below 13 degrees; the surface free energy of the above-mentioned SiO ₂ substrate is above 70 mN/m And 80 mN/m or less, the surface free energy of the above-mentioned SiN substrate is 50 mN/m or more and 60 mN/m or less. Hereinafter, the present invention will be described in detail. In addition, matters common to the sealant for organic EL display elements of the present invention 1 and the sealant for organic EL display elements of the present invention 2 are described as "the sealant for organic EL display elements of the present invention".

The present inventors believe that the reason why the coatability deteriorates when trying to thin the sealant for organic EL display elements is because of the presence on the inorganic material film such as SiO ₂ used to cope with the flexibility. Foreign matter such as SiN is used as the starting point, and the sealant around the foreign matter shrinks, or the sealant cannot adhere to the unevenness of the substrate or inorganic material film. Therefore, the present inventors conducted intensive research and found that by setting the contact angles of both the SiO ₂ substrate and the SiN substrate whose surface free energies are within specific ranges to a specific value or less, it is possible to obtain a film that is suitable for thin film formation. In this case, the present invention was completed by providing a sealant for organic EL display elements that is also excellent in coating properties on substrates and inorganic material films.

The contact angles between the sealant for organic EL display elements of the present invention and the SiO ₂ substrate and the SiN substrate at 25°C are both 13 degrees or less at 25°C; the surface free energy of the above-mentioned SiO ₂ substrate is 70 mN/m or more and 80 mN/m or less. The surface free energy of the above-mentioned SiN substrate is 50 mN/m or more and 60 mN/m or less. By setting the above-mentioned contact angles to 13 degrees or less, the sealant for organic EL display elements of the present invention becomes excellent in the effect of preventing shrinkage caused by foreign matter and the wettability with respect to the substrate or the inorganic material film. The above-mentioned contact angles are all preferably 10 degrees or less, more preferably 8 degrees or less, and still more preferably 6 degrees or less. On the other hand, from the viewpoint of suppressing edge overflow caused by surface unevenness, the above-mentioned contact angles are preferably 5 degrees or more, and more preferably 8 degrees or more. In this specification, the above-mentioned "surface free energy" is measured using the Owens-Wendy evaluation method based on the contact angle between water and methylene iodide at 25°C. Specifically, it means measured using a contact angle meter. The measured value. Examples of the contact angle meter include MSA (manufactured by KRUSS Co., Ltd.) and the like. In addition, in this specification, the above-mentioned "contact angle" means using an inkjet ejection device at 25°C to apply the sealant with a droplet amount of 10 pL from a height of 0.5 mm to the SiO ₂ substrate and the SiN substrate having the above-mentioned surface free energy. When sprayed onto each substrate, the angle of the sealant droplet with respect to each substrate was measured approximately 10 seconds after spraying. Examples of the inkjet ejection device include NanoPrinter500 (manufactured by MICROJET Corporation), and the sealant is ejected at a frequency of 20 kHz. The above-mentioned "angle of the sealant droplet with respect to each substrate" means a value obtained by measuring an image captured by a substrate observation camera of a contact angle meter using image processing software. Examples of the contact angle meter include CAM200 (manufactured by KSV INSTRUMENTS), and examples of the image processing software include CAM2008 (manufactured by KSV INSTRUMENTS).

Examples of methods for setting the above-mentioned contact angles to 13 degrees or less include a method of setting the solubility parameter of the entire curable resin to the following range, a method of combining resins with good wettability to each substrate, and the like. In addition, as a method of setting the above-mentioned contact angles to 5 degrees or more, for example, a method of adding a resin with a high surface tension, a method of combining a resin with good wettability for each substrate and a resin with poor wettability, etc. can be cited.

The preferred upper limit of the viscosity of the sealant for organic EL display elements of the present invention 1 at 25°C is 30 mPa·s. By setting the viscosity to 30 mPa·s or less, the sealing compound for organic EL display elements of the present invention 1 becomes excellent in inkjet coating properties. A more preferable upper limit of the viscosity of the sealant for organic EL display elements of the present invention 1 is 20 mPa·s. Moreover, the preferable lower limit of the viscosity of the sealant for organic EL display elements of Invention 1 is 5 mPa·s. Furthermore, in this specification, the above-mentioned "viscosity" means the value measured using an E-type viscometer at 25°C and 100 rpm.

The preferred upper limit of the viscosity of the sealant for organic EL display elements of the present invention 2 at 25°C is 30 mPa·s. By setting the viscosity to 30 mPa·s or less, the sealant for organic EL display elements of the present invention 2 becomes even more excellent in inkjet coating properties. A more preferable upper limit of the viscosity of the sealant for organic EL display elements of Invention 2 is 20 mPa·s. Moreover, the preferable lower limit of the viscosity of the sealant for organic EL display elements of Invention 2 is 5 mPa·s.

The sealant for organic EL display elements of the present invention 1 has a surface tension of the entire sealant for organic EL display elements at 25° C. of 25 mN/m or more and 38 mN/m or less. By setting the above-mentioned surface tension within this range, the sealing compound for organic EL display elements of Invention 1 becomes excellent in inkjet coating properties. The preferred lower limit of the overall surface tension of the sealant for organic EL display elements of the present invention is 26 mN/m, the preferred upper limit is 37 mN/m, the preferred lower limit is 27 mN/m, and the preferred upper limit is 35 mN/m. . In addition, in this specification, the above-mentioned "surface tension" means the value measured by a dynamic wettability tester at 25°C.

The sealant for organic EL display elements of the present invention 2 has a surface tension of the entire sealant for organic EL display elements at 25° C. of 25 mN/m or more and 38 mN/m or less. By setting the above-mentioned surface tension within this range, the sealing compound for organic EL display elements of Invention 2 becomes more excellent in inkjet coating properties. The preferred lower limit of the overall surface tension of the sealant for organic EL display elements of the present invention is 26 mN/m, the preferred upper limit is 37 mN/m, the preferred lower limit is 27 mN/m, and the preferred upper limit is 35 mN/m. .

The sealing compound for organic EL display elements of the present invention contains curable resin. The sealant for organic EL display elements of the present invention preferably has a solubility parameter (hereinafter also referred to as "SP value") of the entire curable resin of 16.5 (J/cm ³ ) ^1/2 or more and 19.5 (J/cm ³ ) ^1/2 or less. By setting the SP value of the entire curable resin within this range, the sealant for organic EL display elements of the present invention is more effective in preventing shrinkage caused by foreign matter and has better wettability with respect to the substrate or the inorganic material film. Excellent. The more preferable lower limit of the SP value of the entire curable resin is 17.0 (J/cm ³ ) ^1/2 , the more preferable upper limit is 19.2 (J/cm ³ ) ^1/2 , and the more preferable lower limit is 17.7 (J/cm ^{3 )} ) ^1/2 , and the better upper limit is 19.0 (J/cm ³ ) ^1/2 . In addition, in this specification, the above-mentioned "solubility parameter" is a value calculated by Fedors' estimation method. In addition, the above-mentioned "solubility parameter of the entire curable resin" means the average solubility parameter of the weight fraction of each curable resin component used in the sealing compound for organic EL display elements.

The sealing compound for organic EL display elements of the present invention preferably contains two or more types of curable resins as the curable resins, and the difference in SP value between the curable resins is preferably 5 (J/cm ³ ) ^1/2 or less. The content of the curable resin relative to all curable resins is 95% by weight or more. That is, when the sum of the contents of two or more curable resins is calculated such that the difference in SP value between the curable resins does not exist in a combination of curable resins that exceeds 5 (J/cm ³ ) ^1/2 , there is A combination of more than 95% by weight of all curable resins. By setting the SP value difference between the curable resins to 5 (J/cm ³ ) ^1/2 or less and the content of the curable resin to be 95% by weight or more, the resulting sealant for organic EL display elements can prevent The shrinkage effect starting from foreign matter and the wettability to the substrate or inorganic material film become more excellent. The difference in SP value between the curable resins is 5 (J/cm ³ ) ^1/2 or less. The content of the curable resin is more preferably 98% by weight or more, more preferably 99% by weight or more, still more preferably 99.9. It is 99.99 weight % or more, especially preferably 99.99 weight % or more. The sealant for organic EL display elements of the present invention preferably contains two or more types of the above-mentioned curable resins as the above-mentioned curable resins, and the maximum difference in SP value between the curable resins is 5 (J/cm ³ ) ^{1/ 2} or less. That is, it is preferable that there is no combination of curable resins in which the difference in SP value exceeds 5 (J/cm ³ ) ^1/2 . By setting the maximum difference in SP value between the above-mentioned curable resins to 5 (J/cm ³ ) ^1/2 or less, the sealant for organic EL display elements obtained has the effect of preventing shrinkage starting from foreign matter, and The wettability to substrates or inorganic material films becomes even better. More preferably, the maximum difference in SP value between the above-mentioned curable resins is 4 (J/cm ³ ) ^1/2 or less.

The SP value of the curable resin as a whole and the SP value of each curable resin component in the sealant for organic EL display elements of the present invention can be obtained by purifying the sealant for organic EL display elements using a chromatograph, or by The structure and composition are identified through composition analysis such as GC-MS and LC-MS, and the SP value is calculated to obtain it.

The curable resin preferably contains a compound having a siloxane skeleton. By containing the compound having a siloxane skeleton, the surface tension of the obtained sealing compound for organic EL display elements can be easily adjusted, and the flatness of the obtained coating film can become even more excellent.

Examples of the compound having a siloxane skeleton include an epoxy compound having a siloxane skeleton, an oxycyclobutane compound having a siloxane skeleton, a (meth)acrylic acid compound having a siloxane skeleton, and the like. Among them, the compound represented by the following formula (1) is preferred. Furthermore, in this specification, the above-mentioned "(meth)acrylic acid" means acrylic acid or methacrylic acid, the above-mentioned "(meth)acrylic acid compound" means a compound having a (meth)acrylyl group, and the above-mentioned "(meth)acrylic acid compound" means a compound having a (meth)acrylyl group. "Acrylyl" means acryloyl or methacryloyl.

In the formula (1), R ¹ represents an alkyl group having a carbon number of 1 to 10, and X ¹ and X ² each independently represent an alkyl group having a carbon number of 1 to 10, or the following formula (2-1), The group represented by (2-2), (2-3) or (2-4), X ³ represents the following formula (2-1), (2-2), (2-3) or (2 -4) The basis represented. m is an integer from 0 to 100, and n is an integer from 0 to 100. Among them, when n is 0, at least one of X ¹ and X ² represents a basis represented by the following formula (2-1), (2-2), (2-3), or (2-4) .

In the formulas (2-1) to (2-4), R ² represents a bond or an alkylene group with a carbon number of 1 or more and 6 or less. In the formula (2-3), R ³ represents hydrogen or a carbon number of 1 or more. For alkyl groups with 6 or less, R ⁴ represents a bond or methylene group, and in formula (2-4), R ⁵ represents hydrogen or methyl group.

From the viewpoints of storage stability of the obtained sealant for organic EL display elements, adhesion to the substrate or the inorganic material film, ejection stability when inkjet coating is performed, etc., the above-mentioned compound having a siloxane skeleton is Preferably, it is purified in advance to remove high molecular weight substances with a number average molecular weight of 100,000 or more before being blended into the sealant for organic EL display elements. Specifically, the compound having a siloxane skeleton preferably has a content ratio of a high molecular weight body having a number average molecular weight of 100,000 or more and is 0.5% or less. In addition, in this specification, the above-mentioned number average molecular weight and the content ratio of the above-mentioned high molecular weight body are measured by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent, and are calculated by polystyrene conversion. value. In addition, the content ratio of the above-mentioned high molecular weight body can also be measured by GPC. Examples of a column for measuring the number average molecular weight based on polystyrene conversion and the content ratio of the above-mentioned high molecular weight substance by GPC include Shodex LF-804 (manufactured by Showa Denko Co., Ltd.). In addition, the content ratio of the high molecular weight body is calculated based on the area ratio of the above-mentioned GPC.

Examples of methods for purifying the compound having a siloxane skeleton include a method of purifying by distillation, a method of purifying using a column, and the like.

The above-mentioned compounds having a siloxane skeleton may be used alone, or two or more types may be used in combination.

The content of the compound having a siloxane skeleton in the curable resin is preferably less than 40% by weight. By setting the content of the compound having a siloxane skeleton to less than 40% by weight, the resulting sealing compound for organic EL display elements becomes even more excellent in wetting and diffusivity. A more preferable upper limit of the content of the compound having a siloxane skeleton is 35% by weight. Moreover, a preferable lower limit of the content of the compound having a siloxane skeleton in the curable resin is 0.1% by weight. By setting the content of the compound having a siloxane skeleton to 0.1% by weight or more, it becomes easier to adjust the surface tension of the obtained sealing compound for organic EL display elements.

Examples of the curable resin other than the compound having a siloxane skeleton include: an epoxy compound not having a siloxane skeleton (hereinafter also referred to simply as an “epoxy compound”); Oxybutane compounds (hereinafter also referred to as "oxybutane compounds" only), vinyl ether compounds without a siloxane skeleton (hereinafter also referred to as "vinyl ether compounds" only), and vinyl ether compounds without a siloxane skeleton (meth)acrylic acid compounds (hereinafter also referred to as "(meth)acrylic acid compounds"), etc.

Examples of the above-mentioned epoxy compounds include bisphenol A-type epoxy compounds, bisphenol E-type epoxy compounds, bisphenol F-type epoxy compounds, bisphenol S-type epoxy compounds, and bisphenol O-type epoxy compounds. 2,2'-Diallylbisphenol A type epoxy compound, alicyclic epoxy compound, hydrogenated bisphenol type epoxy compound, propylene oxide addition bisphenol A type epoxy compound, resorcinol type Epoxy compounds, biphenyl-type epoxy compounds, thioether-type epoxy compounds, diphenyl ether-type epoxy compounds, dicyclopentadiene-type epoxy compounds, naphthalene-type epoxy compounds, phenol novolac-type epoxy compounds, O-cresol novolac type epoxy compound, dicyclopentadiene novolac type epoxy compound, biphenyl novolac type epoxy compound, naphthol novolak type epoxy compound, glycidylamine type epoxy compound, alkyl Polyol-type epoxy compounds, rubber-modified epoxy compounds, glycidyl ester compounds, etc. Among them, an alkyl polyol type epoxy compound is preferable, and neopentyl glycol diol is most preferable in terms of being less volatile and making the resulting sealant for organic EL display elements more excellent in inkjet coating properties. Glycidyl ether. The above-mentioned epoxy compounds may be used alone or in combination of two or more types.

Examples of the oxybutane compound include 3-(allyloxy)oxybutane, phenoxymethyloxybutane, 3-ethyl-3-hydroxymethyloxybutane, and 3-(allyloxy)oxybutane. -Ethyl-3-(phenoxymethyl)oxycyclobutane, 3-ethyl-3-((2-ethylhexyloxy)methyl)oxycyclobutane, 3-ethyl-3- ((3-(triethoxysilyl)propoxy)methyl)oxybutane, 3-ethyl-3(((3-ethyloxybutan-3-yl)methoxy) Methyl) oxycyclobutane, phenol novolac oxycyclobutane, 1,4-bis(((3-ethyl-3-oxycyclobutyl)methoxy)methyl)benzene, etc. Among them, 3-ethyl-3(((3-ethyloxybutan-3-yl)methoxy)methyl)oxycyclic ring is preferred because of its excellent hardening properties and low outgassing properties. Butane. The above-mentioned oxybutane compounds may be used alone or in combination of two or more types.

Examples of the vinyl ether compound include benzyl vinyl ether, cyclohexanedimethanol monovinyl ether, dicyclopentadiene vinyl ether, 1,4-butanediol divinyl ether, and cyclohexanedimethanol divinyl ether. , diethylene glycol divinyl ether, triethylene glycol divinyl ether, dipropylene glycol divinyl ether, tripropylene glycol divinyl ether, etc. The above-mentioned vinyl ether compounds may be used alone, or two or more types may be used in combination.

Examples of the (meth)acrylic compound include glycidyl (meth)acrylate, 1,6-hexanediol di(meth)acrylate, and 1,9-nonanediol di(meth)acrylate. , Dicyclopentenyl (meth)acrylate, Dicyclopentenyloxyethyl (meth)acrylate, Dicyclopentyl (meth)acrylate, Benzyl (meth)acrylate, Trimethylolpropane Tri(methyl)aryl ester, 1,12-dodecanediol di(meth)acrylate, lauryl (meth)acrylate, etc. The above-mentioned (meth)acrylic acid compounds may be used alone or in combination of two or more types. In addition, in this specification, the said "(meth)acrylate" means acrylate or methacrylate.

The sealing compound for organic EL display elements of the present invention contains a polymerization initiator. As the above-mentioned polymerization initiator, a photocationic polymerization initiator or a thermal cationic polymerization initiator can be preferably used. In addition, depending on the type of the curable resin, a photo radical polymerization initiator or a thermal radical polymerization initiator can be preferably used.

The above-mentioned photocationic polymerization initiator is not particularly limited as long as it generates a protonic acid or a Lewis acid by light irradiation, and may be an ionic photoacid-generating type or a nonionic photoacid-generating type.

Examples of the anionic part of the ionic photoacid generating type photocationic polymerization initiator include: BF ₄ ^- , PF ₆ ^- , SbF ₆ ^- , (BX ₄ ) ^- (where X represents at least two fluorine or trifluoromethyl substituted phenyl), etc. Furthermore, examples of the anionic part include: PF _m (C _n F _2n+1 ) _6-m ^- (where m is an integer from 0 to 5 and n is an integer from 1 to 6) and the like. Examples of the ionic photoacid generating type photocationic polymerization initiator include aromatic sulfonium salts, aromatic ioium salts, aromatic diazonium salts, aromatic ammonium salts, (2,4 -Cyclopentadien-1-yl)((1-methylethyl)benzene)-Fe salt, etc.

Examples of the aromatic sulfide salt include bis(4-(diphenylsonium)phenyl)sulfide bishexafluorophosphate and bis(4-(diphenylsonium)phenyl)sulfide bis. Hexafluoroantimonate, bis(4-(diphenylsulfonyl)phenyl)sulfide bistetrafluoroborate, bis(4-(diphenylsulfonyl)phenyl)sulfide tetrakis(pentafluorophenyl) )Borate, diphenyl-4-(phenylthio)phenylsulfonate hexafluorophosphate, diphenyl-4-(phenylthio)phenylsulfonate hexafluoroantimonate, diphenyl-4-tetrafluoroborate (Phenylthio)phenyl sulfonium, diphenyl-4-(phenylthio)phenyl sulfonium tetrakis (pentafluorophenyl) borate, triphenyl sulfonium hexafluorophosphate, triphenyl sulfonium hexafluoroantimonate, tetrakis Triphenylsulfonium fluoroborate, triphenylsulfonium tetrakis(pentafluorophenyl)borate, bis(4-(di(4-(2-hydroxyethoxy))phenylsulfonyl)phenyl)sulfide bis(hexane) Fluorophosphate, bis(4-(bis(4-(2-hydroxyethoxy))phenylsoniumyl)phenyl)sulfide bishexafluoroantimonate, bis(4-(bis(4-(2) -Hydroxyethoxy))phenylsulfonyl)phenyl)sulfide bistetrafluoroborate, bis(4-(bis(4-(2-hydroxyethoxy))phenylsulfonyl)phenyl)sulfide Ether tetrakis (pentafluorophenyl) borate, tetrakis (pentafluorophenyl) borate tris (4-(4-ethylphenyl) phenylthio) sulfonate, etc.

Examples of the above-mentioned aromatic iodonium salt include diphenyl iodonium hexafluorophosphate, diphenyl iodonium hexafluoroantimonate, diphenyl iodonium tetrafluoroborate, diphenyl iodonium tetrakis(pentafluorophenyl)borate, and diphenyl iodonium hexafluorophosphate. Bis(dodecylphenyl)iodonium fluoride, bis(dodecylphenyl)iodonium hexafluoroantimonate, bis(dodecylphenyl)iodium tetrafluoroborate, tetrakis(pentafluorophenyl)boric acid Bis(dodecylphenyl)phoenium, 4-methylphenyl-4-(1-methylethyl)phenylphosphonium hexafluorophosphate, 4-methylphenyl-4-(1) hexafluoroantimonate -Methyl ethyl) phenyl iodide, 4-methylphenyl-4-(1-methylethyl) phenyl iodide tetrafluoroborate, 4-methylphenyl-4 tetrakis (pentafluorophenyl) borate -(1-methylethyl)phenylquinone, etc.

Examples of the aromatic diazonium salt include phenyldiazo hexafluorophosphate, phenyldiazonium hexafluoroantimonate, phenyldiazonium tetrafluoroborate, phenyldiazonium tetrafluoroborate, and the like. .

Examples of the aromatic ammonium salt include: 1-benzyl-2-cyanopyridinium hexafluorophosphate, 1-benzyl-2-cyanopyridinium hexafluoroantimonate, and 1-benzyl-tetrafluoroborate. 2-cyanopyridinium, 1-benzyl-2-cyanopyridinium tetrakis(pentafluorophenyl)borate, 1-(naphthylmethyl)-2-cyanopyridinium hexafluorophosphate, hexafluoroantimonic acid 1-(naphthylmethyl)-2-cyanopyridinium, 1-(naphthylmethyl)-2-cyanopyridinium tetrafluoroborate, 1-(naphthylmethyl tetrafluoroborate) )-2-cyanopyridinium, etc.

Examples of the (2,4-cyclopentadien-1-yl)((1-methylethyl)benzene)-Fe salt include: hexafluorophosphoric acid (2,4-cyclopentadien-1- yl)((1-methylethyl)benzene)-Fe(II), hexafluoroantimonate (2,4-cyclopentadien-1-yl)((1-methylethyl)benzene)-Fe (II), tetrafluoroboric acid (2,4-cyclopentadien-1-yl) ((1-methylethyl)benzene)-Fe(II), tetrafluoroboric acid (2,4 -Cyclopentadien-1-yl)((1-methylethyl)benzene)-Fe(II), etc.

Examples of the nonionic photoacid generating type photocationic polymerization initiator include: nitrobenzyl ester, sulfonic acid derivative, phosphate ester, phenol sulfonate ester, diazonaphthoquinone, and N-hydroxyquinone. Sulfamic acid esters, etc.

Examples of the commercially available photocationic polymerization initiators include Midori Kagaku's photocationic polymerization initiator, Union Carbide's photocationic polymerization initiator, and ADEKA's photocationic polymerization initiator. Initiator, photocationic polymerization initiator manufactured by 3M Company, photocationic polymerization initiator manufactured by BASF Company, photocationic polymerization initiator manufactured by Rhodia Company, photocationic polymerization initiator manufactured by San-Apro Company, etc. Examples of the photocationic polymerization initiator manufactured by Midori Kagaku Co., Ltd. include DTS-200 and the like. Examples of the photocationic polymerization initiator manufactured by Union Carbide include UVI6990, UVI6974, and the like. Examples of the photocationic polymerization initiator manufactured by ADEKA include SP-150, SP-170, and the like. Examples of the photocationic polymerization initiator manufactured by 3M include FC-508, FC-512, and the like. Examples of the photocationic polymerization initiator manufactured by BASF include IRGACURE261, IRGACURE290, and the like. Examples of the photocationic polymerization initiator manufactured by Rhodia include PI2074 and the like. Examples of the photocationic polymerization initiator manufactured by San-Apro include CPI-100P, CPI-200K, CPI-210S, and the like.

Examples of the thermal cationic polymerization initiator include those in which the anionic part is composed of BF ₄ ^- , PF ₆ ^- , SbF ₆ ^- , or (BX ₄ ) ^- (where X represents at least two fluorine or trifluoromethyl groups substituted sulfonium salt, phosphonium salt, ammonium salt, etc. composed of phenyl group). Among them, sulfonium salts and ammonium salts are preferred.

Examples of the sulfonium salt include triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate, and the like.

Examples of the phosphonium salt include ethyltriphenylphosphonium hexafluoroantimonate, tetrabutylphosphonium hexafluoroantimonate, and the like.

Examples of the ammonium salt include dimethylphenyl(4-methoxybenzyl)ammonium hexafluorophosphate, dimethylphenyl(4-methoxybenzyl)ammonium hexafluoroantimonate, and tetrakis(penta)ammonium salt. Dimethylphenyl(4-methoxybenzyl)ammonium fluorophenyl)borate, dimethylphenyl(4-methylbenzyl)ammonium hexafluorophosphate, dimethylphenyl(4-methoxybenzyl)ammonium hexafluoroantimonate -Methyl benzyl ammonium, dimethyl phenyl (4-methyl benzyl) ammonium hexafluorotetrakis (pentafluorophenyl) borate, methyl phenyl dibenzyl ammonium hexafluorophosphate, methyl hexafluoroantimonate Methyl phenyl benzyl ammonium tetrakis (pentafluorophenyl) borate, phenyl tribenzyl ammonium tetrakis (pentafluorophenyl) borate, dimethyl tetrakis (pentafluorophenyl) borate Phenyl(3,4-dimethylbenzyl)ammonium, N,N-dimethyl-N-benzylanilinium hexafluoroantimonate, N,N-diethyl-N-benzyl tetrafluoroborate Anilinium, N,N-dimethyl-N-benzylpyridinium hexafluoroantimonate, N,N-diethyl-N-benzylpyridinium trifluoromethanesulfonic acid, etc.

Examples of commercially available thermal cationic polymerization initiators include thermal cationic polymerization initiators manufactured by Samshin Chemical Industry Co., Ltd. and thermal cationic polymerization initiators manufactured by King Industries. Examples of the thermal cationic polymerization initiator manufactured by Sanshin Chemical Industry Co., Ltd. include San-Aid SI-60, San-Aid SI-80, San-Aid SI-B3, San-Aid SI-B3A, and San-Aid SI-B4 etc. Examples of the thermal cationic polymerization initiator manufactured by King Industries include CXC1612, CXC1821, and the like.

Examples of the photoradical polymerization initiator include benzophenone compounds, acetophenone compounds, phosphine oxide compounds, titanocene compounds, oxime ester compounds, benzoin ether compounds, and benzyl compounds. base, 9-oxosulfide compounds, etc.

Examples of commercially available ones among the above-mentioned photo-radical polymerization initiators include a photo-radical polymerization initiator manufactured by BASF, a photo-radical polymerization initiator manufactured by Tokyo Chemical Industry Co., Ltd., and the like. Examples of the photoradical polymerization initiator manufactured by BASF include: IRGACURE184, IRGACURE369, IRGACURE379, IRGACURE651, IRGACURE819, IRGACURE907, IRGACURE2959, IRGACURE OXE01, Lucirin TPO, and the like. Examples of the photoradical polymerization initiator manufactured by Tokyo Chemical Industry Co., Ltd. include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, and the like.

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 benzyl peroxide, ketone peroxide, peroxyketal, hydrogen peroxide, dialkyl peroxide, peroxyester, diyl peroxide, and dicarbonate peroxide. wait.

Examples of commercially available thermal radical polymerization initiators include VPE-0201, VPE-0401, VPE-0601, VPS-0501, VPS-1001, and V-501 (all manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.).

The content of the above-mentioned polymerization initiator has a preferable lower limit of 0.01 parts by weight and a preferable upper limit of 10 parts by weight relative to 100 parts by weight of the above-mentioned curable resin. By setting the content of the polymerization initiator to 0.01 parts by weight or more, the curability of the resulting sealing compound for organic EL display elements becomes even more excellent. By setting the content of the above-mentioned polymerization initiator to 10 parts by weight or less, the curing reaction of the sealing compound for organic EL display elements obtained will not become too fast, the workability will become more excellent, and the cured product can be made more uniform. . A more preferable lower limit of the content of the above-mentioned polymerization initiator is 0.05 parts by weight, and a more preferable upper limit is 5 parts by weight.

The sealant for organic EL display elements of the present invention may also contain a sensitizer. The above-mentioned sensitizer has the function of further improving the polymerization initiation efficiency of the above-mentioned polymerization initiator and further promoting the curing reaction of the sealant for organic EL display elements of the present invention.

Examples of the sensitizer include anthracene compounds and 9-oxosulfide. compound, or 2,2-dimethoxy-1,2-diphenylethan-1-one, benzophenone, 2,4-dichlorobenzophenone, o-phenylbenzoic acid methyl Ester, 4,4'-bis(dimethylamino)benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, etc. Examples of the anthracene compound include 9,10-dibutoxyanthracene and the like. As the above 9-oxysulfur Compounds such as 2,4-diethyl 9-oxosulfide wait.

The content of the above-mentioned sensitizer is preferably lower limit is 0.01 parts by weight and upper limit is preferably 3 parts by weight relative to 100 parts by weight of the above-mentioned curable resin. By setting the content of the above-mentioned sensitizer to 0.01 parts by weight or more, the sensitizing effect can be further exerted. By setting the content of the above-mentioned sensitizer to 3 parts by weight or less, the absorption can be transmitted to a deep part without becoming too large. A more preferable lower limit of the content of the above sensitizer is 0.1 parts by weight, and a more preferable upper limit is 1 part by weight.

The sealant for organic EL display elements of the present invention may also contain silane coupling agents, surface modifiers, reinforcing agents, softeners, plasticizers, viscosity adjusters, ultraviolet absorbers, antioxidants and other additives as necessary. When the above-mentioned additives are contained, the above-mentioned properties are further improved from the viewpoint of the prevention of shrinkage caused by foreign matter as the starting point of the sealing compound for organic EL display elements and the ability to follow the irregularities of the substrate or the inorganic material film. The maximum difference in SP value between the components contained in the curable resin and the additive is preferably 5 (J/cm ³ ) ^1/2 or less.

The above-mentioned silane coupling agent has the effect of further improving the adhesion between the sealing agent for organic EL display elements of the present invention and the substrate or inorganic material film. Examples of the silane coupling agent include: 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-isocyanato Propyltrimethoxysilane, etc. These silane coupling agents may be used alone, or two or more types may be used in combination.

The content of the silane coupling agent is preferably 0.1 parts by weight and 10 parts by weight relative to 100 parts by weight of the polymerizable compound. By setting the content of the silane coupling agent within this range, bleeding of excess silane coupling agent is suppressed, and the effect of improving adhesion becomes more excellent. A more preferable lower limit of the content of the above-mentioned silane coupling agent is 0.5 parts by weight, and a more preferable upper limit is 5 parts by weight.

The above-mentioned surface modifying agent has the effect of further improving the flatness of the coating film of the sealant for organic EL display elements of the present invention. Examples of the surface modifying agent include surfactants, leveling agents, and the like.

Examples of the surface modifying agent include polysiloxane-based ones, fluorine-based ones, and the like. Examples of commercially available surface modifying agents include BYK-Chemie Japan's surface modifying agent, AGC Seimi Chemical's surface modifying agent, and the like. Examples of the surface modifier manufactured by BYK-Chemie Japan include BYK-340, BYK-345, and the like. Examples of the above-mentioned surface modifier manufactured by AGC Seimi Chemical include Surflon S-611 and the like.

The sealant for organic EL display elements of the present invention may also contain a solvent for the purpose of adjusting the viscosity, etc. However, there is a risk that the residual solvent may cause the organic light-emitting material layer to deteriorate or produce outgassing, so the content of the solvent is preferably The content is 0.05% by weight or less, and preferably does not contain solvent.

Examples of a method for producing the sealing compound for organic EL display elements of the present invention include a method of mixing a curable resin, a polymerization initiator, and optionally additives such as a silane coupling agent using a mixer. Examples of the mixer include a homogeneous disperser, a homogeneous mixer, a universal mixer, a planetary mixer, a kneader, a three-roller mill, and the like.

The preferred lower limit of the total light transmittance of the cured product of the sealant for organic EL display elements of the present invention for light with a wavelength of 380 nm or more and 800 nm or less is 80%. By making the above-mentioned total light transmittance 80% or more, the optical characteristics of the obtained organic EL display element become even more excellent. The optimal lower limit of the above total light transmittance is 85%. The total light transmittance can be measured using a spectrometer, for example. Examples of the spectrometer include AUTOMATIC HAZE METER MODEL TC-III DPK (manufactured by Tokyo Denshoku Co., Ltd.). In addition, the cured material used for the measurement of the above-mentioned light transmittance, and the following moisture permeability and moisture content can be obtained by irradiating ultraviolet rays with a wavelength of 365 nm at 3000 mJ/cm ² using a light source such as an LED lamp, for example.

The sealant for organic EL display elements of the present invention preferably has a transmittance of 400 nm of 85% or more in an optical path length of 20 μm after irradiating the cured object with ultraviolet rays for 100 hours. By setting the transmittance after 100 hours of irradiation with the ultraviolet rays to 85% or more, the transparency becomes higher, the loss of light emission becomes smaller, and the color reproducibility becomes even better. A more preferable lower limit of the transmittance after 100 hours of irradiation with the ultraviolet rays is 90%, and a further preferable lower limit is 95%. As a light source for irradiating the ultraviolet rays, conventionally known light sources such as xenon lamps and carbon arc lamps can be used.

The sealant for organic EL display elements of the present invention preferably has a moisture permeability of 100 g/m ² at a thickness of 100 μm measured after exposing the cured product to an environment of 85°C and 85% RH for 24 hours in accordance with JIS Z 0208. the following. By setting the moisture permeability to 100 g/m ² or less, the effect of preventing the deterioration of the organic light-emitting material layer caused by moisture in the cured material becomes more excellent, and the reliability of the obtained organic EL display element becomes even more excellent.

The sealant for organic EL display elements of the present invention preferably has a moisture content of less than 0.5% when the cured product is exposed to an environment of 85°C and 85% RH for 24 hours. By reducing the moisture content of the cured material to less than 0.5%, the effect of preventing the deterioration of the organic light-emitting material layer caused by the moisture in the cured material becomes more excellent, and the reliability of the obtained organic EL display element becomes even more excellent. A more preferable upper limit of the moisture content of the hardened material is 0.3%. Examples of methods for measuring the moisture content include the method of determining the moisture content by the Kaffir-Snow method in accordance with JIS K 7251, or the method of determining the weight increase after water absorption in accordance with JIS K 7209-2.

Examples of a method for manufacturing an organic EL display element using the sealant for organic EL display elements of the present invention include the following method. The method includes applying the sealant for organic EL display elements of the present invention to a base by an inkjet method. The step of hardening the coated organic EL display element sealant by light irradiation and/or heating.

In the step of applying the sealant for organic EL display elements of the present invention to the base material, the sealant for organic EL display elements of the present invention can be applied to the entire surface of the base material, or can be applied to only part of the base material. part. The shape of the sealing portion of the sealant for organic EL display elements of the present invention formed by coating is not particularly limited as long as it is a shape that can protect the laminate having the organic light-emitting material layer from external air. It may be a shape that completely covers the laminated body, a closed pattern may be formed on the peripheral part of the laminated body, or a pattern having a shape with partial openings may be formed on the peripheral part of the laminated body.

When the sealant for organic EL display elements of the present invention is hardened by light irradiation, the sealant for organic EL display elements of the present invention can be cured by irradiation with a wavelength of 300 nm or more and 400 nm or less and 300 mJ/cm ² It is better hardened by the cumulative light amount of more than 3000 mJ/ ^cm2 and less than 3000 mJ/cm2.

Examples of light sources used for the above light irradiation include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, excimer lasers, chemical lamps, black light lamps, microwave excited mercury lamps, metal halide lamps, sodium lamps, and halogen lamps. , xenon lamps, LED lamps, fluorescent lamps, sunlight, electron beam irradiation devices, etc. These light sources can be used alone, or two or more types can be used in combination. These light sources are appropriately selected based on the absorption wavelength of the above-mentioned photocationic polymerization initiator or photoradical polymerization initiator.

Examples of methods for irradiating the sealant for organic EL display elements of the present invention with light include simultaneous irradiation with various light sources, sequential irradiation with time intervals, and a combination of simultaneous irradiation and sequential irradiation. Any irradiation method may be used.

The cured product obtained by curing the sealant for organic EL display elements by light irradiation and/or heating may be further covered with an inorganic material film. As the inorganic material constituting the above-mentioned inorganic material film, previously known ones can be used, and examples include silicon nitride (SiN _x or SiO _X N _Y ) or silicon oxide (SiO _x ). The above-mentioned inorganic material film may be composed of one layer, or may be laminated with a plurality of layers. Moreover, the above-mentioned laminate may be covered alternately with the above-mentioned inorganic material film and the resin film composed of the sealant for organic EL display elements of the present invention.

The method of manufacturing the above-mentioned organic EL display element may also include the following steps: laminating a base material coated with the sealant for organic EL display elements of the present invention (hereinafter also referred to as "a base material") to another base material. The base material on which the sealant for organic EL display elements of the present invention is applied (hereinafter also referred to as "a base material") may be a base material on which a laminate having an organic light-emitting material layer is formed, or may be a base material on which no such laminate is formed. The base material of the body. When the above-mentioned one base material is a base material on which the above-mentioned laminated body is not formed, as long as the above-mentioned other base material is bonded, the above-mentioned one base material can be coated in a manner that can protect the above-mentioned laminated body from the influence of external gas. The organic EL display element of the present invention can be covered with a sealant. That is, the entire surface may be coated on the portion that will become the above-mentioned laminated body when another base material is bonded, or the sealant portion of the closed pattern may be formed to form the portion that will become the above-mentioned laminated body when another base material is bonded together. A shape that completely includes the location.

The above-mentioned step of hardening the sealant for the organic EL display element by light irradiation and/or heating may be performed before the step of laminating the above-mentioned one substrate to the above-mentioned another substrate, or may be performed after the above-mentioned one substrate and the above-mentioned substrate are bonded together. The step of laminating another base material is carried out later. When the step of hardening the sealant for the organic EL display element by light irradiation and/or heating is performed before the step of laminating the above-mentioned one substrate to the above-mentioned other substrate, the organic EL display element of the present invention The sealant is preferably irradiated with light and/or heated so that the pot life until the curing reaction proceeds and the sealant cannot be bonded is 1 minute or more. By setting the application time to 1 minute or more, hardening will not proceed excessively before bonding the one base material to the other base material, and higher bonding strength can be obtained.

In the step of laminating the above-mentioned one base material and the above-mentioned another base material, the method of laminating the above-mentioned one base material and the above-mentioned another base material is not particularly limited, and it is preferably lamination in a reduced pressure environment. The preferable lower limit of the vacuum degree of the above-mentioned reduced pressure environment is 0.01 kPa, and the preferable upper limit is 10 kPa. By setting the vacuum degree of the decompressed environment to this range, it does not take a long time to reach the vacuum state due to the airtightness of the vacuum device or the capacity of the vacuum pump, and the one substrate and the other substrate can be removed more efficiently. Bubbles in the sealant for organic EL display elements of the present invention when materials are bonded. [Effects of the invention]

According to the present invention, it is possible to provide a sealant for organic EL display elements that is excellent in coating properties for substrates or inorganic material films even when thinned.

Hereinafter, although an Example is given and this invention is demonstrated in further detail, this invention is not limited only to these Examples.

(Preparation of SiO ₂ substrate) SiO 2 was chemically evaporated on alkali-free glass with a film thickness of 1000 nm using an ICP-CVD device (manufactured by SELVAC) to produce _{a SiO 2 substrate} . Using a contact angle meter, the surface free energy after evaporation was measured based on the contact angle between water and diiodomethane using the Owens-Wendy evaluation method. The result was 73.0 mN/m. As a contact angle meter, MSA (manufactured by KRUSS Co., Ltd.) was used. Furthermore, the atomic ratio in the SiO ₂ film was measured using an XPS device (manufactured by ULVAC-PHI Co., Ltd.). As a result, Si atoms were 31.3% and O atoms were 63.2%.

(Production of SiN substrate) Using an ICP-CVD device (manufactured by SELVAC), SiN was chemically evaporated on alkali-free glass with a film thickness of 1000 nm to produce a SiN substrate. Using a contact angle meter, the surface free energy after evaporation was measured based on the contact angle between water and diiodomethane using the Owens-Wendy evaluation method. The result was 58.0 mN/m. As a contact angle meter, MSA (manufactured by KRUSS Co., Ltd.) was used. Furthermore, the atomic ratio in the SiN film was measured using an XPS device (manufactured by ULVAC-PHI Corporation). As a result, Si atoms were 44.8% and N atoms were 48.0%.

(Examples 1 to 9, Comparative Examples 1 to 4) According to the blending ratios described in Tables 1 and 2, use a homogeneous dispersion type stirring mixer to uniformly stir and mix each material at a stirring speed of 300 rpm. Sealing compounds for organic EL display elements of Examples 1 to 9 and Comparative Examples 1 to 4 were produced. As a homogeneous phase dispersing machine type stirring mixer, a homogeneous phase dispersing machine type L (manufactured by PRIMIX Corporation) was used. Compounds with a siloxane skeleton in the table are those that have been purified by distillation before being mixed with other components. As the oxybutane compound having a siloxane skeleton in the table, one obtained by the following method was used. That is, 0.1 mol of 1,1,3,3-tetramethyldisiloxane, 0.2 mol of allyloxyoxycyclobutane, and platinum (0)-1,3-divinyl-1,1, 100 ppm of 3,3-tetramethyldisiloxane complex solution (manufactured by Sigma-Aldrich) was mixed and heated at 80°C for 5 hours. As allyloxyoxybutane, AL-OX (manufactured by Yokkaichi Gosei Co., Ltd.) was used. The completion of the reaction was confirmed by NMR, and the obtained solution was purified by distillation, thereby obtaining a high-purity oxybutane-modified disiloxane compound as an oxybutane compound having a siloxane skeleton. Through ¹ H-NMR, GPC, and FT-IR analysis, it was confirmed that the obtained oxycyclobutane-modified disiloxane compound was a compound represented by the following formula (3). Using an inkjet ejection device, each of the sealants for organic EL display elements obtained in the Examples and Comparative Examples was ejected onto SiO with a surface free energy of 73.0 mN/m obtained in the above "(Preparation of SiO ₂ substrate)" ₂ substrate, and the SiN substrate with a surface free energy of 58.0 mN/m obtained in the above "(Preparation of SiN substrate)". As the inkjet ejection device, NanoPrinter500 (manufactured by MICROJET) was used, and the sealant was ejected under the conditions of 25°C, a droplet volume of 10 pL, a pitch of 800 μm, a drop height of 0.5 mm from the substrate, and a frequency of 20 kHz. For the droplets of sealant sprayed for about 10 seconds, use image processing software to measure the images captured by the substrate observation camera of the contact angle meter, and display the measured contact angle with respect to each substrate. In Tables 1 and 2. As the contact angle meter, CAM200 (manufactured by KSV INSTRUMENTS) was used, and as the image processing software, CAM2008 was used. For each sealing compound for organic EL display elements obtained in the Examples and Comparative Examples, the SP value of the entire curable resin and the maximum difference in SP value between the curable resins were calculated by Fedors' method, and these are shown in In Tables 1 and 2. Moreover, the surface tension of each sealant for organic EL display elements obtained in the Examples and Comparative Examples was measured by the Wilhelmy method using a surface tensiometer at 25° C., and the measured surface tension is shown in Tables 1 and 2. As a surface tensiometer, DY-300 (manufactured by Kyowa Interface Science Co., Ltd.) was used. Furthermore, the viscosity of each sealant for organic EL display elements obtained in the Examples and Comparative Examples was measured using an E-type viscometer under the conditions of 25° C. and 100 rpm. The measured viscosity is shown in Tables 1 and 2. As the E-type viscometer, VISCOMETER TV-22 (manufactured by Toki Industrial Co., Ltd.) was used.

＜Evaluation＞ The following evaluations were performed on each sealing compound for organic EL display elements obtained in the Examples and Comparative Examples. The results are shown in Tables 1 and 2.

(1) Wetting and spreading properties Using an inkjet ejection device, the sealants for organic EL display elements obtained in the Examples and Comparative Examples were placed with a droplet volume of 10 pL at a pitch of 48 μm and a size of 8 cm × 8 cm. The surface free energy obtained in the above "(Preparation of SiO ₂ substrate)" is coated onto the SiO ₂ substrate with a surface free energy of 73.0 mN/m. As the inkjet ejection device, NanoPrinter500 (manufactured by MICROJET Corporation) was used. The sealant on the substrate was visually observed 3 minutes after application, and the number of uncoated portions that were not wetted and spread and became stripes was confirmed. The case where the number of striped uncoated parts is 0 is regarded as "◎", the case where there are more than 1 and less than 2 stripes is regarded as "○", the case where there are more than 2 and less than 5 stripes is regarded as "○""△", and five or more cases were marked as "×" to evaluate the wettability and spreadability.

(2) Foreign matter covering property Use a spreader to spread silicon nitride particles and silicon dioxide particles onto the SiO ₂ substrate with a surface free energy of 73.0 mN/m obtained in the above "(Preparation of SiO ₂ substrate)". As the silicon nitride particles, SN-E10 (manufactured by Ube Kosan Co., Ltd.) was used, and as the silicon dioxide particles, SEAHOSTAR (manufactured by Nippon Shokubai Co., Ltd.) was used. Using an inkjet ejection device, the sealant for each organic EL display element obtained in the Example and the Comparative Example was applied with a droplet amount of 10 pL so that the gap was 48 μm and the area was 8 cm×8 cm. SiO ₂ substrate. As the inkjet ejection device, NanoPrinter500 (manufactured by MICROJET Corporation) was used. After coating for 3 minutes, irradiation was performed using a 395 nm UVLED with an illumination intensity of 1000 mW/cm ² so that the cumulative light intensity became 1000 mJ/cm ² . Assuming that the dispersed silicon nitride particles or silicon dioxide particles were foreign matter, it was confirmed that The number of pinholes for every 10 foreign objects randomly selected. The number of pinholes per 10 foreign objects is 0 as "◎", the number of pinholes as 1 or more but less than 2 is "○", and the number of pinholes as 2 or more but less than 3 is "○". "△", and three or more cases as "×" to evaluate the foreign matter coverage. In addition, those that could not be evaluated due to poor wetting and diffusion were set as "-".

(3) Reliability of organic EL display elements (3-1) Preparation of a substrate equipped with a laminate with an organic light-emitting material layer. ITO electrodes are placed on glass with a length of 25 mm, a width of 25 mm, and a thickness of 0.7 mm. The film formed into a thickness of 1000 Å serves as the substrate. Use acetone, alkaline aqueous solution, ion-exchange water, and isopropyl alcohol to ultrasonically clean the above-mentioned substrate for 15 minutes, then clean it with boiled isopropyl alcohol for 10 minutes, and then pre-clean it with a UV-ozone cleaner. handle. As a UV-ozone cleaner, NL-UV253 (manufactured by Japan Laser Electronics Co., Ltd.) is used. Secondly, fix the pretreated substrate on the substrate support of the vacuum evaporation device, and put N,N'-bis(1-naphthyl)-N,N'-diphenylbenzidine ( α-NPD) 200 mg, put 200 mg tris(8-hydroxyquinoline)aluminum (Alq ₃ ) into another stoneware crucible, and reduce the pressure in the vacuum chamber to 1×10 ^-4 Pa. Afterwards, 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 positive hole transport layer with a film thickness of 600 Å. Then, the crucible filled with Alq ₃ was heated, and an organic light-emitting material layer with a film thickness of 600 Å was formed at an evaporation speed of 15 Å/s. Thereafter, the substrate with the positive hole transport layer and the organic light-emitting material layer formed was moved to another vacuum evaporation device equipped with a tungsten resistance heating boat, and was installed in a tungsten resistance heating boat in the vacuum evaporation device. Add 200 mg of lithium fluoride and 1.0 g of aluminum wire in another tungsten resistance heating boat. Thereafter, the pressure in the evaporator of the vacuum evaporation device was reduced to 2×10 ^-4 Pa, and lithium fluoride was deposited to a film of 5 Å at a deposition rate of 0.2 Å/s, and aluminum was deposited at a deposition rate of 20 Å/s. Film formation speed of 1000 Å. The inside of the evaporator was returned to normal pressure with nitrogen gas, and the substrate on which the laminate having an organic light-emitting material layer of 10 mm × 10 mm was placed was taken out.

(3-2) Covering of the inorganic material film A A mask having an opening of 13 mm × 13 mm is provided to cover the entirety of the laminate on which the obtained laminate is placed, and is formed by a plasma CVD method. Inorganic material film A. The plasma CVD method was performed under the following conditions: SiH ₄ gas and nitrogen gas were used as raw material gases, the flow rates of each were set to 10 sccm for SiH ₄ gas and 200 sccm for nitrogen gas, and the RF power was set to 10 W (frequency 2.45 GHz). ), set the temperature in the chamber to 100°C, and set the pressure in the chamber to 0.9 Torr. The thickness of the formed inorganic material film A is about 1 μm.

(3-3) Formation of Resin Protective Film The sealant pattern for each organic EL display element obtained in Examples and Comparative Examples was applied to the obtained substrate using an inkjet ejection device. As the inkjet ejection device, NanoPrinter500 (manufactured by MICROJET Corporation) was used. Thereafter, an LED lamp is used to irradiate ultraviolet light with a wavelength of 365 nm at 3000 mJ/cm ² to harden the sealant of the organic EL display element to form a resin protective film.

(3-4) Coating using inorganic material film B After the resin protective film is formed, a mask with an opening of 12 mm × 12 mm is provided to cover the resin protective film, and the inorganic material film B is formed using the plasma CVD method to obtain an organic EL display element. The plasma CVD method is performed under the same conditions as the above "(3-2) Coating of inorganic material film A". The thickness of the formed inorganic material film B is about 1 μm.

(3-5) Luminous state of organic EL display elements After the obtained organic EL display element was exposed to an environment with a temperature of 85°C and a humidity of 85% for 100 hours, a voltage of 3 V was applied, and the luminous state of the organic EL display element (whether there were dark spots and extinction around the pixels) was visually observed. The situation where there are no dark spots or peripheral extinction and uniform light emission is regarded as "○", the situation where there are no dark spots or peripheral extinction but a slight decrease in brightness is found as "△", the situation where dark spots or peripheral extinction is found is regarded as "△" "×" evaluates the reliability of organic EL display elements.

(4) Surface unevenness Use an inkjet ejection device to apply the sealant for organic EL display elements obtained in Examples 6 and 7 and Comparative Examples 1 and 2 with a droplet amount of 10 pL at a pitch of 48 μm and 8 cm. ×8 cm area was applied to the SiO ₂ substrate with a surface free energy of 73.0 mN/m obtained in the above "(Preparation of SiO ₂ substrate)". As the inkjet ejection device, NanoPrinter500 (manufactured by MICROJET Corporation) was used. For the sealant on the substrate after coating for 3 minutes, use an LED lamp to irradiate ultraviolet light with a wavelength of 365 nm at 3000 mJ/cm ² to harden the sealant. For the hardened sealant, according to JIS1982, measure the height of the convex portion with a surface roughness measuring instrument using a 2CR filter and an R2 μm stylus at a feed speed of 0.2 mm/s. As a surface roughness measuring instrument, SE300 (manufactured by Kosaka Laboratory Co., Ltd.) was used. The height of the convex part is confirmed by taking the concave part on the surface as 0. The height of the convex portion is less than 0.5 μm as "◎", the height of 0.5 μm or more and less than 1.0 μm is "○", and the height of 1.0 μm or more but less than 1.5 μm is "△" , the case where the height is 1.5 μm or more is regarded as "×", and the surface unevenness is evaluated. In addition, those who have not been evaluated for surface unevenness are set as "-".

[Table 1]

[Table 2] [Industrial availability]

According to the present invention, it is possible to provide a sealant for organic EL display elements that is excellent in coating properties for substrates or inorganic material films even when thinned.

without

without

Claims (8)

A sealant for organic EL display elements, which contains a curable resin and a polymerization initiator, has a surface tension of 25 mN/m or more and 38 mN/m or less at 25°C, and the sealant for organic EL display elements is in contact with a SiO ₂ substrate The contact angles of the SiO 2 substrate and the SiN substrate at 25°C are both below 13 degrees; the surface free energy of the above-mentioned SiO ₂ substrate is above 70mN/m and below 80mN/m, and the surface free energy of the above-mentioned SiN substrate is above 50mN/m and below 60mN/m. Hereinafter, the above-mentioned curable resin contains a compound selected from the group consisting of a compound having a siloxane skeleton, an epoxy compound not having a siloxane skeleton, an oxycyclobutane compound not having a siloxane skeleton, and a vinyl ether not having a siloxane skeleton. At least one kind from the group consisting of compounds and (meth)acrylic compounds without a siloxane skeleton. The sealant for organic EL display elements as described in claim 1 has a viscosity of 5 mPa‧s or more and 30 mPa‧s or less at 25°C. A sealant for organic EL display elements, which is applied by the inkjet method, and is characterized in that it contains a curable resin and a polymerization initiator, and has a surface tension of 25 mN/m or more and 38 mN/m at 25°C. below, and the contact angles between the above-mentioned sealant for organic EL display elements and the SiO ₂ substrate and the SiN substrate at 25°C are both 13 degrees or below; the surface free energy of the above-mentioned SiO ₂ substrate is 70 mN/m or above and 80 mN/m or below, as mentioned above The surface free energy of the SiN substrate is 50 mN/m or more and 60 mN/m or less. The above-mentioned curable resin contains a compound selected from a compound having a siloxane skeleton, an epoxy compound not having a siloxane skeleton, and a compound having a siloxane skeleton. At least one kind from the group consisting of an oxybutane compound, a vinyl ether compound not having a siloxane skeleton, and a (meth)acrylic acid compound not having a siloxane skeleton. The sealant for organic EL display elements according to claim 1, 2 or 3, wherein the solubility parameter of the curable resin as a whole is 16.5 (J/cm ³ ) ^1/2 or more and 19.5 (J/cm ³ ) ^{1/ 2} or less. The sealant for organic EL display elements according to claim 1, 2 or 3, wherein the content of the compound having a siloxane skeleton in the curable resin does not reach 40% by weight. The sealant for organic EL display elements according to claim 1, 2 or 3, wherein the solubility parameter of the entire curable resin is 17.7 (J/cm ³ ) ^1/2 or more. The sealant for organic EL display elements as described in claim 1 or 3 has a viscosity of 30 mPa‧s or less at 25°C. The sealant for organic EL display elements according to claim 1, 2 or 3, wherein the content of the polymerization initiator is 0.01 to 10 parts by weight relative to 100 parts by weight of the curable resin.