Ink composition for forming an electronic device sealing layer, method for forming an electronic device sealing layer, and electronic device sealing layer

Abstract

The ink composition for forming an electronic device sealing layer of the present invention contains polysilazane, and the ink composition contains at least one or more high-drying solvents A with a vapor pressure of 8.0×10 2 Pa or more at 20 °C and at least one or more low-drying solvents B with a vapor pressure of 4.0×10 2 Pa or less. When the mole fraction of the above high-drying solvent A relative to the total amount of solvents is set as m a1 、m a2 、…, and the mole fraction of the above low-drying solvent B relative to the total amount of solvents is set as m b1 、m b2 、…, and the vapor pressure of the above high-drying solvent A is set as P a1 、P a2 、…, and the vapor pressure of the above low-drying solvent B is set as P b1 、P b2 、…, when P 合计 represented by the following formula (i) is in the range of 0.5×10 2 ~3.6×10 2 Pa. (Formula i) P 合计 =P a1 ×m a1 +P a2 ×m a2 +…、+P b1 ×m b1 +P b2 ×m b2 +…。

Description

Technical Field

[0001] The present invention relates to an ink composition for forming a sealing layer of an electronic device, a method for forming a sealing layer of an electronic device, and a sealing layer of an electronic device, and particularly relates to an ink composition for forming a sealing layer of an electronic device, etc., which has excellent sealing performance and bending resistance and can suppress the deterioration of an electronic device. Background Art

[0002] For electronic devices, particularly organic electroluminescent devices (hereinafter also referred to as "organic EL devices" or "organic EL elements"), in order to prevent the organic materials and electrodes used from deteriorating due to moisture, a scheme of covering the surface of the organic EL element with a sealing layer has been proposed.

[0003] As a technique for sealing an organic EL element, for example, in the technique described in Patent Document 1, an organic EL device is disclosed, which includes: a first protective film formed on the surface of the organic EL element in a dry process (CVD method) so as to cover the organic EL element; and a second protective film formed on the surface of the first protective film by a wet process and used to fill the holes in the non-attached portion of the first protective film. In addition, it is described that polysilazane is used as the second protective film.

[0004] However, in the organic EL device described in Patent Document 1 above, under high temperature and high humidity of 85°C and 85% RH for 100 hours or more, there is a problem of water penetration at the interface between the first protective film and the second protective film (presumably) due to deterioration of the interface adhesion between the first protective film and the second protective film, and the sealing performance is poor.

[0005] In addition, when using inkjet for patterning the second protective film above, when applying the inkjet method to the composition disclosed in Patent Document 1, there are problems with the ejection property and patterning accuracy of the ink. Furthermore, crystal boundaries of the second protective film formed by the inkjet printing method are generated, and the problem of water penetration at the above interface is significant.

[0006] On the other hand, Patent Document 2 discloses a composition for forming a silica film, which contains a silicon-containing polymer and a mixed solvent containing at least two solvents, and the above mixed solvent has a surface tension of 5 to 35 nN / m at 25°C.

[0007] Furthermore, Patent Document 3 discloses a coating liquid, which is a coating liquid containing polysilazane, and contains the above polysilazane and an oxidized polysilazane in which an oxygen atom is introduced into a part of the above polysilazane and the atomic composition ratio (O / Si) of oxygen (O) atoms to silicon (Si) atoms is in the range of 0.01 to 0.1.

[0008] However, when forming a sealing layer by inkjet coating on a CVD layer using the gas-phase method with the composition described in Patent Document 2 or the coating liquid described in Patent Document 3, although the ejection property of the ink is improved, water permeation at the interface between the CVD layer and the coating film on the CVD layer becomes a problem. In addition, there is a problem that the adhesion at the interface during bending also decreases.

[0009] Prior Art Documents

[0010] Patent Documents

[0011] Patent Document 1: Japanese Patent Application Laid-Open No. 2005-056587

[0012] Patent Document 2: Japanese Patent Application Laid-Open No. 2017-031040

[0013] Patent Document 3: Japanese Patent Application Laid-Open No. 2019-036517 Summary of the Invention

[0014] Problems to be Solved by the Invention

[0015] The present invention has been completed in view of the above problems and situations, and the problem to be solved is to provide an ink composition for forming an electronic device sealing layer, an electronic device sealing layer forming method, and an electronic device sealing layer, which have excellent sealing performance and bending resistance and can suppress the deterioration of electronic devices.

[0016] Means for Solving the Problems

[0017] In order to solve the above problems, the inventor of the present invention, in the process of studying the causes of the above problems, found that: by using an ink composition containing polysilazane, a highly volatile solvent A, and a lowly volatile solvent B and specifying the sum of the products of the mole fractions of the respective solvents and the vapor pressures of the respective solvents within a specific range for forming a sealing layer, the sealing performance and bending resistance are excellent, and the deterioration of electronic devices can be suppressed, and the present invention has been completed.

[0018] That is, the above problems related to the present invention are solved by the following means.

[0019] 1. An ink composition for forming an electronic device sealing layer, which is an ink composition for forming an electronic device sealing layer, contains polysilazane, and the ink composition contains at least one or more highly volatile solvents A having a vapor pressure of 8.0×10 2 Pa or more at 20°C and at least one or more lowly volatile solvents B having a vapor pressure of 4.0×10 2 Pa or less. Let the mole fraction of the above highly volatile solvent A relative to the total amount of solvents be m a1 、m a2 、…, and let the mole fraction of the above lowly volatile solvent B be m b1 、mb2 ..., the vapor pressure of the above-mentioned highly drying solvent A is set as P a1 , P a2 ..., the vapor pressure of the above-mentioned low drying solvent B is set as P b1 , P b2 ..., when P represented by the following formula (i) 合计 is within the range of 0.5×10 2 to 3.6×10 2 Pa.

[0020] (Formula i) P 合计 = P a1 ×m a1 + P a2 ×m a2 +… + P b1 ×m b1 + P b2 ×m b2 +…

[0021] 2. The ink composition for forming an electronic device sealing layer according to the first item, wherein the above-mentioned highly drying solvent A is dibutyl ether.

[0022] 3. The ink composition for forming an electronic device sealing layer according to the first or second item, wherein the above-mentioned low drying solvent B is decalin.

[0023] 4. The method for forming an electronic device sealing layer is a method for forming a sealing layer by using the ink composition for forming an electronic device sealing layer according to any one of the first to third items, and includes:

[0024] a step of forming a first sealing layer on the electronic device by a vapor phase method; and

[0025] a step of forming a second sealing layer by coating the ink composition for forming an electronic device sealing layer on the above-mentioned first sealing layer.

[0026] 5. The method for forming an electronic device sealing layer according to the fourth item further includes: a step of forming a third sealing layer on the above-mentioned second sealing layer by a vapor phase method.

[0027] 6. The method for forming an electronic device sealing layer according to the fourth or fifth item, wherein the step of forming the above-mentioned second sealing layer uses an inkjet method.

[0028] 7. The electronic device sealing layer is an electronic device sealing layer for sealing an electronic device, and has:

[0029] a first sealing layer containing silicon nitride, silicon oxide or silicon oxynitride;

[0030] mixed and present in the defect area of the above-mentioned first sealing layer;

[0031] A second sealant layer containing polysilazane, disposed adjacent to the first sealant layer described above; and

[0032] A polysilazane region filled with polysilazane, disposed in the gap between the defect region and the first sealant layer described above.

[0033] 8. The electronic device sealant layer according to item 7, wherein when observing a cross section using an electron microscope, the interval of the gap is 15 nm or less.

[0034] Effects of the Invention

[0035] By the above means of the present invention, it is possible to provide an ink composition for forming an electronic device sealant layer, a method for forming an electronic device sealant layer, and an electronic device sealant layer, which have excellent sealing performance and bending resistance and can suppress the deterioration of electronic devices.

[0036] Regarding the mechanism or action mechanism of the manifestation of the effects of the present invention, although not clear, it is speculated as follows.

[0037] By using an ink composition containing polysilazane, a highly volatile solvent A, and a lowly volatile solvent B and specifying the sum of the product of the mole fraction of each solvent and the vapor pressure of each solvent within a specific range for forming the sealant layer, during the drying process of the solvent, a difference in the drying rate occurs between the highly volatile solvent A and the lowly volatile solvent B. It is speculated that by utilizing the drying rate difference between the highly volatile solvent A and the lowly volatile solvent B, the highly volatile solvent A dries first and is fixed, which helps to achieve stable adhesion to the underlying layer (first sealant layer) formed by the vapor phase method. In addition, it is speculated that by enhancing the interface through adhesion to the underlying layer, the diffusion of moisture at the interface is suppressed, preventing the deterioration of electronic devices caused by moisture permeating through the interface.

[0038] In addition, by containing the lowly volatile solvent B, even when the inkjet method is used, the ejection property and patterning accuracy of the ink are excellent. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A diagram (electron micrograph) showing a cross-sectional image of the electronic device sealant layer of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0040] The ink composition for forming an electronic device sealant layer of the present invention is an ink composition for forming an electronic device sealant layer, which contains polysilazane, and the ink composition contains a highly volatile solvent A having a vapor pressure of 8.0×10 2 Pa or more at 20 °C and 4.0×10 2At least one or more low-drying solvents B below Pa, and the mole fraction of the above high-drying solvent A relative to the total amount of solvents is set to m a1 , m a2 , …, and the mole fraction of the above low-drying solvent B is set to m b1 , m b2 , …, and the vapor pressure of the above high-drying solvent A is set to P a1 , P a2 , …, and the vapor pressure of the above low-drying solvent B is set to P b1 , P b2 , …, when P represented by the following formula (i) 合计 is in the range of 0.5×10 2 ~3.6×10 2 Pa.

[0041] (Formula i) P 合计 =P a1 ×m a1 +P a2 ×m a2 +…、+P b1 ×m b1 +P b2 ×m b2 +…

[0042] This feature is a common or corresponding technical feature in the following embodiments.

[0043] As an embodiment of the present invention, from the viewpoint of the solubility of polysilazane, it is preferable that the above high-drying solvent A is dibutyl ether, and from the aspect of obtaining appropriate ink ejection properties and pattern formation properties, it is preferable that the above low-drying solvent B is decalin.

[0044] The method for forming an electronic device sealing layer of the present invention is a method for forming a sealing layer using the above ink composition for forming an electronic device sealing layer, and it includes: a step of forming a first sealing layer on an electronic device by a vapor phase method; and a step of forming a second sealing layer by coating the above ink for forming an electronic device sealing layer on the above first sealing layer.

[0045] Thus, by utilizing the drying speed difference between the high-drying solvent A and the low-drying solvent B contained in the above ink composition, the high-drying solvent A dries first and is thereby fixed, and the adhesion between the first sealing layer and the second sealing layer formed by the vapor phase method is excellent, and the sealing performance and bending resistance are excellent.

[0046] In addition, the interface is strengthened by the adhesion between the first sealing layer and the second sealing layer, thereby suppressing the diffusion of moisture at the interface and being able to suppress the deterioration of the electronic device caused by moisture permeating through the interface.

[0047] Further, from the aspect of more excellent sealing performance, it is preferable to have a step of forming a third sealing layer on the above-mentioned second sealing layer by a vapor phase method.

[0048] From the aspect of being able to form a layer with high precision, it is preferable that the above-mentioned step of forming the second sealing layer uses an inkjet method.

[0049] The electronic device sealing layer of the present invention has: a first sealing layer containing silicon nitride, silicon oxide or silicon oxynitride; a defect region mixedly present in the above-mentioned first sealing layer; a second sealing layer adjacent to the above-mentioned first sealing layer and containing polysilazane; and a polysilazane region filled in the gap between the above-mentioned defect region and the above-mentioned first sealing layer.

[0050] Thus, through the polysilazane region filled in the gap between the defect region and the first sealing layer, the adhesion between the first sealing layer and the second sealing layer is excellent, and the sealing performance and bending resistance are excellent. In addition, the interface is strengthened by the adhesion between the first sealing layer and the second sealing layer, thereby suppressing the diffusion of moisture at the interface and being able to suppress the deterioration of the electronic device caused by the moisture permeating through the interface.

[0051] From the aspect of obtaining a dominant effect compared with conventional inks, it is preferable that the interval of the above-mentioned gap is 15 nm or less when observing the cross section using an electron microscope.

[0052] Hereinafter, the present invention, its constituent elements, and the forms and manners for implementing the present invention will be described. It should be noted that in this application, "~" is used in the meaning of including the numerical values described before and after it as the lower limit value and the upper limit value.

[0053] [Outline of the ink composition for forming the electronic device sealing layer of the present invention]

[0054] The ink composition for forming the electronic device sealing layer of the present invention (hereinafter also simply referred to as the ink composition) is an ink composition for forming an electronic device sealing layer, which contains polysilazane. This ink composition contains at least one or more high-drying solvents A with a vapor pressure of 8.0×10 2 Pa or more at 20°C and at least one or more low-drying solvents B with a vapor pressure of 4.0×10 2 Pa or less. Let the mole fraction of the above-mentioned high-drying solvent A with respect to the total amount of the solvent be m a1 、m a2 、…, let the mole fraction of the above-mentioned low-drying solvent B be m b1 、m b2 、…, let the vapor pressure of the above-mentioned high-drying solvent A be P a1 、P a2 、…, let the vapor pressure of the above-mentioned low-drying solvent B be P b1 、P b2When it is …, P represented by the following formula (i) 合计 is in the range of 0.5×10 2 to 3.6×10 2 Pa.

[0055] (Formula i) P 合计 = P a1 × m a1 + P a2 × m a2 + … + P b1 × m b1 + P b2 × m b2 + …

[0056] Herein, the "electronic device" in the present invention refers to an element that generates, amplifies, converts, or controls an electrical signal by using the kinetic energy, potential energy, etc. possessed by electrons. For example, active elements such as light-emitting diode elements, organic electroluminescent elements, photoelectric conversion elements, and transistors can be cited. In addition, in the present invention, passive elements such as "resistors" and "capacitors" that are responsible for receiving work such as "resistance" and "accumulation" from other actions are also included in the electronic devices.

[0057] Therefore, the ink composition of the present invention is used to form a sealing layer for sealing the above-mentioned electronic device.

[0058] <High-drying solvent A>

[0059] The vapor pressure of the high-drying solvent A related to the present invention at 20 °C is 8.0×10 2 Pa or more, and the upper limit value is 2.0×10 4 Pa or less.

[0060] In order to solve the problems of the present invention, in order to obtain an appropriate drying rate, it is required to be 8.0×10 2 Pa or more. In addition, in order to obtain stability against compositional changes caused by natural drying before and during ink ejection, it is required to be 2.0×10 4 Pa or less.

[0061] The vapor pressure (Pa) of the high-drying solvent A related to the present invention at 20 °C can be obtained by the following method. For example, the lead method according to JIS K2258-1:2009, the three-expansion method according to JIS K2258-2:2009, etc. can be cited. In addition, the static method, boiling point method, isopiestic apparatus, gas flow method, DSC method, which are known as general vapor pressure measurement methods, can also be applied. Furthermore, vapor pressure data described in known literature such as "New Edition Solvent Pocket Book" (edited by the Organic Synthetic Chemistry Society, Ohm Co., Ltd.) can also be used.

[0062] As the above-mentioned highly drying solvent A with a vapor pressure of 8.0×10 2 Pa or higher, as long as it does not react with polysilazane, there is no particular limitation, and known solvents can be appropriately used. Specifically, aromatic solvents, alkane solvents, ester solvents, ether solvents, ketone solvents, amide solvents, other solvents, etc. can be cited. For example, xylene, ethylene glycol monomethyl ether (alias: methyl cellosolve), isopentyl acetate (alias: isoamyl acetate), dibutyl ether (DBE), chlorobenzene, n-butyl acetate, methyl n-butyl ketone, tetrachloroethylene (alias: perchloroethylene), isobutyl acetate, methyl isobutyl ketone, n-propyl acetate, toluene, 1,4-dioxane, isopropyl alcohol, trimethylpentane (TMP), isopropyl acetate, trichloroethylene, 1,2-dichloroethane (alias: dichloroethane), ethyl acetate, methyl ethyl ketone, carbon tetrachloride, 1,1,1-trichloroethane, n-hexane, tetrahydrofuran, etc. Among them, DBE and xylene are preferred. In addition, one kind can be used, or multiple kinds can be used.

[0063] <Low drying solvent B>

[0064] The vapor pressure of the low drying solvent B involved in the present invention at 20°C is 4.0×10 2 Pa or lower, and as the lower limit value, it is 1.0×10 -1 Pa or higher.

[0065] In order to solve the problems of the present invention and obtain an appropriate drying rate, it needs to be 4.0×10 2 Pa or lower, and in order to obtain the drying property for removing the solvent after coating, it needs to be 1.0×10 -1 Pa or higher.

[0066] The method for measuring the vapor pressure (Pa) of the low drying solvent B at 20°C can adopt the same method as the method for measuring the vapor pressure of the above-mentioned highly drying solvent A.

[0067] As the above-mentioned vapor pressure of 4.0×10 2For the low-drying solvent B of less than Pa, as long as it does not react with polysilazane, there is no particular limitation, and known solvents can be appropriately used. Specifically, aromatic solvents, alkane solvents, ester solvents, ether solvents, ketone solvents, amide solvents, other solvents, etc. can be cited. For example, hexadecane, diethylene glycol dibutyl ether (DEGDBE), diphenyl ether, ethylene glycol, 1-methylnaphthalene, cyclohexylbenzene, 3,3,5-trimethylcyclohexanol, 4'-methylacetophenone, decamethylcyclopentasiloxane (D5), N-methylpyrrolidone (NMP), 4-ethylanisole, tetralin, cresol, butyl benzoate, diethylene glycol diacrylate, diethylene glycol diethyl ether, ethylene glycol monobutyl ether (alias: butyl cellosolve), n-butylbenzene, cyclohexyl acetate, 1,2-dichlorobenzene, ethylene glycol monoethyl ether acetate (alias: cellosolve acetate), methylcyclohexanol, phenetole, sec-butylbenzene, tert-butylbenzene, decalin (alias: decahydronaphthalene), 1,3,5-trimethylbenzene (mesitylene), diethylene glycol dimethyl ether, N,N-dimethylformamide, methylcyclohexanone, ethylene glycol monophenyl ether (EGMPE), etc. Among them, decahydronaphthalene, DEGDBE, and tetralin are preferred. In addition, one kind can be used, or multiple kinds can be used.

[0068] Regarding the ink composition of the present invention, the molar fraction of the high-drying solvent A relative to the total amount of solvents is set as m a1 , m a2 , …, and the molar fraction of the low-drying solvent B is set as m b1 , m b2 , …, and the vapor pressure of the high-drying solvent A is set as P a1 , P a2 , …, and the vapor pressure of the low-drying solvent B is set as P b1 , P b2 , … When this is the case, P 合计 represented by the following formula (i) is in the range of 0.5×10 2 ~3.6×10 2 Pa, and more preferably in the range of 1.4×10 2 ~3.4×10 2 Pa.

[0069] (Formula i) P 合计 =P a1 ×m a1 +P a2 ×m a2 +…、+P b1 ×m b1 +P b2 ×m b2 +…

[0070] As long as the molar fractions of the above-mentioned highly drying solvent A and low-drying solvent B satisfy the above formula (i), there are no particular limitations. For example, it is preferable that the molar fraction of the highly drying solvent A is in the range of 5 to 40, and the molar fraction of the low-drying solvent B is in the range of 95 to 60.

[0071] <Poly(silazane)>

[0072] The "poly(silazane)" used in the present invention is a polymer having a silicon-nitrogen bond in its structure and is a polymer that becomes a precursor of silicon oxynitride. A polymer having the structure represented by the following general formula (1) is preferably used.

[0073] [Chemical formula 1]

[0074] General formula (1)

[0075]

[0076] In the formula, R 1 , R 2 and R 3 each represent a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, an alkylsilyl group, an alkylamino group, or an alkoxy group.

[0077] In the present invention, from the viewpoint of the denseness of the obtained sealing layer, it is particularly preferable that R 1 , R 2 and R 3 are all hydrogen atoms, i.e., a perhydrogenated poly(silazane).

[0078] In addition, the weight-average molecular weight Mw of the poly(silazane) used in the present invention is preferably 1000 or more, more preferably 3000 or more, and particularly preferably 7000 or more. In addition, it is preferable to contain 50% by mass or more of such a high-molecular poly(silazane) relative to all the poly(silazane). By containing a high-molecular poly(silazane), the viscosity of the ink composition can be adjusted.

[0079] As the poly(silazane) having Mw of 3000 or more, for example, referring to the method described in Japanese Patent No. 5172867, a poly(silazane) having only a high-molecular component with a weight-average molecular weight Mw of 3000 or more can be obtained.

[0080] The poly(silazane) used in the present invention can be a commercially available poly(silazane) in a solution state dissolved in an organic solvent.

[0081] As the organic solvent, as long as it is an organic solvent capable of dissolving poly(silazane), there are no particular limitations. It is preferably an organic solvent that does not contain water and reactive groups (such as hydroxyl groups or amino groups, etc.) that easily react with poly(silazane) and is non-reactive with poly(silazane), and more preferably an aprotic organic solvent.

[0082] Specifically, as the solvent, aprotic solvents can be cited: for example, hydrocarbon solvents such as aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons like pentane, hexane, cyclohexane, toluene, xylene, Solvesso, and terpane; halogenated hydrocarbon solvents such as dichloromethane and trichloroethane; esters such as ethyl acetate and butyl acetate; ketones such as acetone and methyl ethyl ketone; ethers such as aliphatic ethers and alicyclic ethers like dibutyl ether, dioxane, and tetrahydrofuran: for example, tetrahydrofuran, dibutyl ether, mono- and polyalkylene glycol dialkyl ethers (diglyme). The above solvents are selected according to the solubility of the polysilazane, the evaporation rate of the solvent, etc., and can be used alone or in the form of a mixture of two or more.

[0083] In addition, the polysilazane stock solution formed by dissolving the polysilazane in an organic solvent may be catalyst-free or may contain a catalyst.

[0084] As the catalyst, a basic catalyst is preferred, and in particular, amine catalysts such as N,N-diethylethanolamine, N,N-dimethylethanolamine, triethanolamine, triethylamine, 3-morpholinopropylamine, N,N,N',N'-tetramethyl-1,3-diaminopropane, N,N,N',N'-tetramethyl-1,6-diaminohexane, metal catalysts such as Pt compounds like acetylacetone Pt, Pd compounds like propionic acid Pd, Rh compounds like acetylacetone Rh, and N-heterocyclic compounds can be cited. Among them, amine catalysts are preferably used. As the concentration of the catalyst added at this time, based on the silicon compound, it is preferably in the range of 0.1 to 5% by mass, more preferably in the range of 0.5 to 2% by mass. By setting the catalyst addition amount within this range, it is possible to avoid the formation of excessive silanol, the decrease in film density, and the increase in film defects caused by the rapid progress of the reaction. In addition, by adding these catalysts, the oxidation of the polysilazane can be carried out with a smaller amount of moisture.

[0085] As commercially available products of the polysilazane solution, NN120-20, NAX120-20, NL120-20, etc. manufactured by AZ Electronic Materials Co., Ltd. can be cited.

[0086] In addition, regarding the details of polysilazane, reference can be made to paragraphs "0024" to "0040" of Japanese Patent Application Laid-Open No. 2013-255910, paragraphs "0037" to "0043" of Japanese Patent Application Laid-Open No. 2013-188942, paragraphs "0014" to "0021" of Japanese Patent Application Laid-Open No. 2013-151123, paragraphs "0033" to "0045" of Japanese Patent Application Laid-Open No. 2013-052569, paragraphs "0062" to "0075" of Japanese Patent Application Laid-Open No. 2013-129557, paragraphs "0037" to "0064" of Japanese Patent Application Laid-Open No. 2013-226758, etc., which are publicly known in the past, and adopted accordingly.

[0087] The viscosity of the ink composition of the present invention is in the range of 1 to 20 mPa·s at 20°C, and is preferably in terms of having an appropriate viscosity and good ejection stability using the inkjet method.

[0088] The viscosity can be measured using a commercially available rotary or vibrating viscometer.

[0089] In addition, from the aspect of being able to adjust the viscosity of the ink composition, it is preferred that the ink composition of the present invention contains a volatile thickening agent.

[0090] As the volatile thickening agent, there is no particular limitation as long as it is a liquid compound having a volatility that does not hinder the film formation of the ink composition and a viscosity of approximately 1 mPa·s or more at 20°C, or a liquid mixture that becomes a viscosity of 1 mPa·s or more by mixing. Preferably, it is a non-protic, non-aqueous volatile oil or glycol ether having compatibility with the above-mentioned highly drying solvent A, low drying solvent B, and polysilazane, and no reactivity with polysilazane.

[0091] Specifically, as the volatile oil, for example, terpin, volatile oil, mineral spirits, α-pinene, isoparaffin, volatile silicone oil, etc. can be cited. As the glycol ether, for example, diethylene glycol dibutyl ether (DEGDBE), tripropylene glycol dimethyl ether, diethylene glycol butyl methyl ether, dipropylene glycol dimethyl ether, etc. can be cited. Among them, from the aspect of being able to be used as a diluting solvent at the same time, compounds such as diethylene glycol dibutyl ether and volatile silicone oil having appropriate viscosity, volatility, and non-aqueous solubility are preferred.

[0092] The ink composition of the present invention can be obtained by adding the highly drying solvent A and the low drying solvent B to the polysilazane stock solution dissolved in the above-mentioned organic solvent so as to achieve a specified mole fraction.

[0093] In addition, in the polysilazane stock solution, in addition to the above-mentioned highly drying solvent A and low drying solvent B, it is preferred to further add the above-mentioned volatile thickening agent.

[0094] Preferably, stirring is performed from the addition to after the addition of the above-mentioned highly drying solvent A, low drying solvent B, and volatile tackifier, and heating and stirring are more preferably performed. As the heating temperature, it is preferably below the boiling points of the above-mentioned highly drying solvent A and low drying solvent B, and more preferably in the range of 50 to 120°C. As the heating means and stirring means, there are no particular limitations, and general methods for heating and stirring a solution can be applied. In the case of heating, it is preferably a method of indirectly heating the container or kettle containing the solution to heat the liquid. In addition, in the case of stirring, methods such as rotating the shaft equipped with stirring blades by an electric motor and using a stir bar and stirrer for stirring if the amount of liquid is small can be applied.

[0095] In addition, in order to stabilize the coating liquid (defoam), heating, stirring, or ultrasonic dispersion is preferred.

[0096] Regarding the ink composition of the present invention, from the aspect of not generating bubbles and being able to form a stabilized ink composition, the increase amount (ΔV) of the dissolved gas amount over time is preferably ΔV < 100 ppm / day. In addition, it is more preferably ΔV < 10 ppm / day, and particularly preferably ΔV < 1 ppm / day.

[0097] Regarding the method for measuring the dissolved gas amount, for example, the gas generated after heating, stirring, or ultrasonic dispersion of the ink composition is trapped, and GC / MS and a detector suitable for the gas to be detected are combined, whereby the identification and quantification of the gas can be performed. In addition, as the gases that are worried about being generated in the oxidation reaction of polysilazane and dissolved in the coating liquid, ammonia gas and silane gas are known. Therefore, a gas detection tube or gas detector corresponding to the target gas can also be used to quantify the generation amount, and the total amount is estimated as the dissolved gas amount.

[0098] [Method for forming electronic device sealing layer]

[0099] The method for forming an electronic device sealing layer of the present invention is a method for forming a sealing layer using the above-mentioned ink composition of the present invention, which includes: a step of forming a first sealing layer on the electronic device by a vapor phase method; and a step of forming a second sealing layer by coating the above-mentioned ink composition on the first sealing layer.

[0100] In addition, from the aspect of being able to further improve the sealing performance of the electronic device, it is preferably to include a step of forming a third sealing layer on the second sealing layer by a vapor phase method.

[0101] <First sealing layer forming step>

[0102] The first sealing layer forming step forms a first sealing layer on the electronic device by a vapor phase method.

[0103] As the vapor phase method, sputtering methods (for example, including magnetron cathode sputtering, planar magnetron sputtering, diode AC planar magnetron sputtering, diode AC rotary magnetron sputtering, etc., reactive sputtering methods), evaporation methods (for example, resistance heating evaporation, electron beam evaporation, ion beam evaporation, plasma-assisted evaporation, etc.), thermal CVD method, catalytic chemical vapor deposition method (Cat-CVD), capacitively coupled plasma CVD method (CCP-CVD), photo-CVD method, plasma CVD method (PE-CVD), epitaxial growth method, atomic layer growth method, and other chemical vapor deposition methods can be cited. Among them, it is preferably formed by the CVD method.

[0104] The first sealing layer contains silicon nitride (SiN), silicon oxide (monosilicon oxide, silicon dioxide, etc.), or silicon oxynitride.

[0105] The thickness of the first sealing layer is, for example, preferably in the range of 10 to 1000 nm, more preferably in the range of 100 to 500 nm.

[0106] <Second Sealing Layer Forming Step>

[0107] The second sealing layer forming step forms the second sealing layer by coating the above-mentioned ink composition of the present invention on the above-mentioned first sealing layer.

[0108] Specifically, it is preferable to coat the above-mentioned ink composition on the above-mentioned first sealing layer (coating step), and further perform a drying step of drying the obtained coating film. In addition, a step of subjecting the obtained coating film to vacuum ultraviolet irradiation in a nitrogen atmosphere for modification treatment may also be provided after the drying step.

[0109] (Coating Step)

[0110] As a method for coating the ink composition, any appropriate method can be adopted. For example, spin coating method, roll coating method, flow coating method, inkjet method, spraying method, printing method, dip coating method, casting film forming method, bar coating method, gravure printing method, etc. can be cited. Among them, from the aspect of fine patterning required when sealing electronic devices such as organic EL elements as needed, the inkjet method is preferably used.

[0111] As the inkjet method, a known method can be used.

[0112] The inkjet method is roughly divided into two types: the drop-on-demand method and the continuous method, both of which can be used. As the drop-on-demand method, there are electro-mechanical conversion methods (such as single-chamber type, double-chamber type, bending type, piston type, shared mode type, shared wall type, etc.), electro-thermal conversion methods (such as thermal inkjet type, Bubble Jet (registered trademark) type, etc.), electrostatic attraction methods (such as electric field control type, slit jet type, etc.), and discharge methods (such as spark jet type, etc.). From the viewpoints of the cost of the inkjet head and productivity, it is preferable to use a head of the electro-mechanical conversion method or the electro-thermal conversion method. It should be noted that sometimes the method of dropping droplets (such as a coating liquid) by the inkjet method is called the "inkjet method".

[0113] When coating the above ink composition, it is preferably carried out under a nitrogen atmosphere.

[0114] (Drying process)

[0115] In the above drying process, the coating film obtained by coating the above ink composition is dried to remove the solvent (including solvents such as highly drying solvent A and low drying solvent B) contained in the coating film.

[0116] It is also preferable that the drying process is carried out under a nitrogen atmosphere. Regarding the drying method, reference can be made to paragraphs "0058" to "0064" of Japanese Patent Laid-Open No. 2014-151571 and paragraphs "0052" to "0056" of Japanese Patent Laid-Open No. 2011-183773, etc. for adoption.

[0117] (Modification treatment process)

[0118] In the above modification treatment process, there may be a process of performing modification treatment by irradiating the obtained coating film with vacuum ultraviolet light under a nitrogen atmosphere after the drying process.

[0119] The modification treatment refers to the conversion reaction of polysilazane to silica or silicon oxynitride. The modification treatment is also carried out under a nitrogen atmosphere or reduced pressure in a glove box or the like.

[0120] In the present invention, the modification treatment can select a known method based on the conversion reaction of polysilazane. In the present invention, it is preferable to use a conversion reaction using plasma, ozone, or ultraviolet light that can carry out the conversion reaction at a low temperature. Plasma and ozone can use known methods in the past. In the present invention, it is preferable to: dispose the above coating film, irradiate vacuum ultraviolet light with a wavelength of 200 nm or less (also called VUV) for modification treatment, thereby forming the second sealing layer of the present invention.

[0121] The thickness of the second sealing layer is preferably in the range of 10 to 1000 nm, more preferably in the range of 100 to 500 nm.

[0122] The second sealing layer may be a layer that modifies the entire layer. The thickness of the modified layer after the modification treatment is preferably in the range of 1 to 50 nm, and more preferably in the range of 1 to 30 nm.

[0123] In the step of irradiating the above-mentioned vacuum ultraviolet rays for the modification treatment, the illuminance of the vacuum ultraviolet rays at the coating film surface of the coating film is preferably in the range of 30 to 200 mW / cm 2 and more preferably in the range of 50 to 160 mW / cm 2 By setting the illuminance of the vacuum ultraviolet rays to 30 mW / cm 2 or more, the modification efficiency can be sufficiently improved. When it is 200 mW / cm 2 or less, the incidence of damage to the coating film can be extremely suppressed, and in addition, the damage to the substrate can be reduced, so it is preferred.

[0124] For the irradiation of the vacuum ultraviolet rays, the irradiation energy of the vacuum ultraviolet rays on the coating film surface is preferably in the range of 1 to 10 J / cm 2 From the viewpoints of the barrier property and the moisture and heat resistance for maintaining the desiccant function, it is more preferably in the range of 3 to 7 J / cm 2 in the range.

[0125] It should be noted that as the light source of the vacuum ultraviolet rays, a rare gas excimer lamp is preferably used. Since the vacuum ultraviolet light has absorption by oxygen, the efficiency in the vacuum ultraviolet ray irradiation step is likely to decrease. Therefore, it is preferred to perform the vacuum ultraviolet light irradiation in a state of as low an oxygen concentration as possible. That is, the oxygen concentration during the vacuum ultraviolet light irradiation is preferably in the range of 10 to 10000 ppm, more preferably in the range of 50 to 5000 ppm, further preferably in the range of 80 to 4500 ppm, and most preferably in the range of 100 to 1000 ppm.

[0126] The modification treatment can also be carried out in combination with a heat treatment. As the heating conditions, by preferably using a heat treatment at a temperature in the range of 50 to 300 °C, more preferably in the range of 60 to 150 °C, for preferably 1 second to 60 minutes, more preferably 10 seconds to 10 minutes, the dehydration condensation reaction during the modification can be promoted, and the modified body can be formed more effectively.

[0127] As the heat treatment, for example, the following methods can be cited: a method of bringing the substrate into contact with a heating element such as a heating block and heating the coating film by heat conduction; a method of heating the atmosphere by an external heater using a resistance wire or the like; a method of using light in the infrared region such as an IR heater, etc., but there is no particular limitation. In addition, a method that can maintain the smoothness of the coating film containing the silicon compound can be appropriately selected.

[0128] <Third Sealing Layer Formation Step>

[0129] In the third sealing layer forming step, a third sealing layer is formed on the second sealing layer by a vapor phase method.

[0130] As the vapor phase method, similar to the vapor phase method used in the first sealing layer forming step, sputtering methods (including, for example, reactive sputtering methods such as magnetron cathode sputtering, planar magnetron sputtering, diode AC planar magnetron sputtering, diode AC rotary magnetron sputtering, etc.), evaporation methods (such as resistance heating evaporation, electron beam evaporation, ion beam evaporation, plasma-assisted evaporation, etc.), thermal CVD method, catalytic chemical vapor deposition method (Cat-CVD), capacitively coupled plasma CVD method (CCP-CVD), photo-CVD method, plasma CVD method (PE-CVD), epitaxial growth method, atomic layer growth method, and other chemical vapor deposition methods can be cited. Among them, it is preferably formed by CVD method.

[0131] The third sealing layer contains silicon nitride (SiN), silicon oxide (such as monosilicon oxide, silicon dioxide, etc.), or silicon oxynitride.

[0132] The thickness of the third sealing layer is, for example, preferably in the range of 10 to 1000 nm, more preferably in the range of 100 to 500 nm.

[0133] <Determination of the second sealing layer from polysilazane>

[0134] In the second sealing layer according to the present invention, it is a preferred embodiment to preferably use polysilazane as the precursor, and particularly preferably use perhydropolysilazane to form. The second sealing layer as the final product is a layer formed by polysilazane, and it can be confirmed by analyzing through the following method.

[0135] In the present invention, an example of using perhydropolysilazane as polysilazane will be described.

[0136] When the general composition of commercially available perhydropolysilazane is set as SiN v H w v becomes 0.78 to 0.80. Regarding the precursor layer formed by perhydropolysilazane, it inhales moisture and oxygen in the forming atmosphere and releases ammonia and hydrogen, and the composition changes as shown in the following formulas (A) and (B).

[0137] [Chemical formula 2]

[0138] Formula (A)

[0139]

[0140] Formula (B)

[0141]

[0142] In this process, the rule of releasing 1 nitrogen and introducing 3 oxygens is generally followed. This also applies to the cases where various modification treatments mentioned above are carried out. Therefore, when using SiO x N y to represent the composition of the second sealing layer formed by coating with perhydropolysilazane, the relationship between x and y follows the following formula (C).

[0143] Formula (C)

[0144] y = 0.8 - x / 3, x≥0, y≥0,

[0145] In the case of the original composition being SiN 0.8 H w when analyzing the composition distribution in the thickness direction of the layer formed by coating with perhydropolysilazane using XPS, any composition at each measurement point in the thickness direction also applies to the above formula (with a few percent error).

[0146] Therefore, when analyzing the composition distribution in the thickness direction of the layer containing Si, when using SiO x N y to represent, with respect to the thickness of the formed second sealing layer, when the composition of more than 80% of the measurement points has a y value falling within the range of ±2% of (0.8 - x / 3), it can be presumed that the film is a sealing layer formed by perhydropolysilazane.

[0147] [Electronic device sealing layer]

[0148] The electronic device sealing layer of the present invention has: a first sealing layer containing silicon nitride, silicon oxide or silicon oxynitride; a defect region mixedly present in the above first sealing layer; a second sealing layer adjacent to the above first sealing layer and containing polysilazane; and a polysilazane region provided in the gap between the above defect region and the above first sealing layer and filled with polysilazane.

[0149] Regarding the electronic device sealing layer of the present invention, it is formed by the above electronic device sealing layer forming method. That is, the above ink composition of the present invention is used to form the second sealing layer and the polysilazane region.

[0150] In addition, a third sealing layer formed by a vapor phase method can be further provided on the above second sealing layer for the electronic device sealing layer of the present invention.

[0151] <First sealing layer>

[0152] The first sealing layer is a layer formed on the electronic device by the above vapor phase method. Specifically, it contains silicon nitride (SiN), silicon oxide (such as monosilicon oxide, silicon dioxide, etc.) or silicon oxynitride.

[0153] <Defect region>

[0154] In the above-mentioned first sealing layer, defective regions are mixedly present.

[0155] The "defective region" referred to in the present invention means: foreign substances mixedly present in the first sealing layer due to the vapor phase method when forming the above-mentioned first sealing layer, and portions where film formation by the above-mentioned vapor phase method grows abnormally due to these foreign substances.

[0156] Specifically, as shown in Figure 1 , a region including the foreign substance 4 and the abnormally grown portion 5 around the foreign substance 4 is referred to as a defective region 6. In addition, a gap 7 is generated between such a defective region 6 and the above-mentioned first sealing layer 2. The interval P of the gap 7 is preferably 15 nm or less, more preferably 10 nm or less, when performing cross-sectional observation at a magnification of 200k (acceleration voltage 200 kV) using an electron microscope (for example, JEM-2010F manufactured by JEOL Ltd.).

[0157] The interval P of the above-mentioned gap 7 is measured as follows.

[0158] First, horizontal lines A1 at the lower 1 / 3 position and A2 at the 2 / 3 position of the thickness of the first sealing layer 2 are respectively drawn. Then, in the first sealing layer 2, tangents B1 connecting the points where the horizontal line A1 at the 1 / 3 position intersects the horizontal line A2 at the 2 / 3 position are drawn. Similarly, in the abnormally grown portion 5, tangents B2 connecting the points where the horizontal line A1 at the 1 / 3 position intersects the horizontal line A2 at the 2 / 3 position are also drawn. Then, the distance between the midpoints of the above-mentioned tangent B1 on the first sealing layer 2 side and the above-mentioned tangent B2 on the abnormally grown portion 5 side is measured.

[0159] It should be noted that in Figure 1 , reference numeral 1 denotes an electronic device, and reference numeral 3 denotes a second sealing layer.

[0160] A polysilazane region filled with polysilazane is provided in the above-mentioned gap.

[0161] Regarding the above-mentioned polysilazane region, it is formed by coating the above-mentioned ink composition (second sealing layer forming step) containing polysilazane, a highly drying solvent A, and a low drying solvent B on the above-mentioned first sealing layer, and coating the ink composition in the above-mentioned gap. Therefore, by drying the coated film coated with the above-mentioned ink composition, the solvents (solvents including the highly drying solvent A and the low drying solvent B, etc.) contained in the coated film are removed, and a polysilazane region containing polysilazane is formed in the above-mentioned gap. Through such a polysilazane region, the gap between the first sealing layer and the defective region is sealed, so the sealing performance is improved.

[0162] <Second Sealing Layer>

[0163] The second sealing layer is a layer containing polysilazane and is disposed adjacent to the above-mentioned first sealing layer. The second sealing layer is formed by coating the above-mentioned ink composition on the above-mentioned first sealing layer.

[0164] Therefore, similar to the above-mentioned polysilazane region, the second sealing layer becomes a layer containing polysilazane by drying the coating film coated with the above-mentioned ink composition to remove the solvent (solvents including highly volatile solvent A and low-volatile solvent B, etc.) contained in the coating film.

[0165] <Third Sealing Layer>

[0166] The third sealing layer is a layer disposed adjacent to the above-mentioned second sealing layer and formed by the above-mentioned vapor phase method. Specifically, it contains silicon nitride (SiN), silicon oxide (monosilicon oxide, silicon dioxide, etc.) or silicon oxynitride, similar to the first sealing layer.

[0167] [Electronic Device]

[0168] In the method for forming an electronic device sealing layer and the electronic device sealing layer of the present invention, examples of the electronic device to be sealed include an organic EL element, a liquid crystal display element (LCD), a thin film transistor, a touch panel, an electronic paper, a solar cell (PV), etc. From the viewpoint of more effectively obtaining the effects of the present invention, an organic EL element or a solar cell is preferred, and an organic EL element is particularly preferred.

[0169] <Organic EL Element>

[0170] As the organic EL element employed in the electronic device according to the present invention, it may be a bottom-emitting type, that is, an electronic device that emits light from the transparent substrate side.

[0171] Specifically, the bottom-emitting type is constituted by sequentially laminating a transparent electrode serving as a cathode, a light-emitting functional layer, and a counter electrode serving as an anode on a transparent substrate.

[0172] In addition, the organic EL element according to the present invention may also be a top-emitting type, that is, an electronic device that emits light from the transparent electrode side serving as a cathode opposite to the substrate.

[0173] Specifically, the top-emitting type has a structure in which a counter electrode serving as an anode is provided on the substrate side, and a light-emitting functional layer and a transparent electrode serving as a cathode are sequentially laminated on its surface.

[0174] Hereinafter, representative examples of the constitution of the organic EL element are shown.

[0175] (i) Anode / Hole Injection and Transport Layer / Light-Emitting Layer / Electron Injection and Transport Layer / Cathode

[0176] (ii) Anode / hole injection and transport layer / light-emitting layer / hole blocking layer / electron injection and transport layer / cathode

[0177] (iii) Anode / hole injection and transport layer / electron blocking layer / light-emitting layer / hole blocking layer / electron injection and transport layer / cathode

[0178] (iv) Anode / hole injection layer / hole transport layer / light-emitting layer / electron transport layer / electron injection layer / cathode

[0179] (v) Anode / hole injection layer / hole transport layer / light-emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode

[0180] (vi) Anode / hole injection layer / hole transport layer / electron blocking layer / light-emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode

[0181] Furthermore, the organic EL element may also have a non-light-emitting intermediate layer. The intermediate layer may be a charge generation layer or a multi-photon unit structure.

[0182] Regarding the outline of the organic EL element to which the present invention can be applied, for example, the structures described in JP-A No. 2013-157634, JP-A No. 2013-168552, JP-A No. 2013-177361, JP-A No. 2013-187211, JP-A No. 2013-191644, JP-A No. 2013-191804, JP-A No. 2013-225678, JP-A No. 2013-235994, JP-A No. 2013-243234, JP-A No. 2013-243236, JP-A No. 2013-242366, JP-A No. 2013-243371, JP-A No. 2013-245179, JP-A No. 2014-003249, JP-A No. 2014-003299, JP-A No. 2014-013910, JP-A No. 2014-017493, JP-A No. 2014-017494, etc. can be cited.

[0183] <Substrate>

[0184] As the substrate (hereinafter also referred to as a support substrate, matrix, substrate, support, etc.) that can be used for the above-mentioned organic EL element, specifically, glass or a resin film is preferably applied, and in the case where flexibility is required, a resin film is preferred.

[0185] In addition, it may be transparent or opaque. In the case of a so-called bottom emission type in which light is extracted from the substrate side, the substrate is preferably transparent.

[0186] Preferred resins include polyester resins, methacrylic resins, methacrylic acid-maleic acid copolymers, polystyrene resins, transparent fluorine resins, polyimides, fluorinated polyimide resins, polyamide resins, polyamide-imide resins, polyetherimide resins, cellulose acylate resins, polyurethane resins, polyetheretherketone resins, polycarbonate resins, alicyclic polyolefin resins, polyarylate resins, polyethersulfone resins, polysulfone resins, cycloolefin copolymers, fluorene ring-modified polycarbonate resins, alicyclic-modified polycarbonate resins, fluorene ring-modified polyester resins, acrylic compounds and other thermoplastic resins. The resins may be used alone or in combination of two or more.

[0187] The substrate is preferably made of a material having heat resistance. Specifically, a substrate having a linear expansion coefficient of 15 ppm / K or more and 100 ppm / K or less and a glass transition temperature (Tg) of 100° C. or more and 300° C. or less is used.

[0188] The substrate meets the necessary conditions for use as an electronic component and a laminated film for a display. That is, when the sealing film of the present invention is used in these applications, the substrate is sometimes exposed to a process above 150°C. In this case, if the linear expansion coefficient of the substrate exceeds 100ppm / K, the substrate size is unstable when flowing in the process at the above temperature, and it is easy to produce the undesirable situation of deterioration of the blocking performance or the undesirable situation of being unable to withstand the hot process accompanied by thermal expansion and contraction. If it is less than 15ppm / K, the film will break like glass and sometimes the flexibility will deteriorate.

[0189] The Tg and linear expansion coefficient of the substrate can be adjusted by additives and the like.

[0190] As more preferred specific examples of the thermoplastic resin that can be used as the base material, for example, polyethylene terephthalate (PET: 70 °C), polyethylene naphthalate (PEN: 120 °C), polycarbonate (PC: 140 °C), alicyclic polyolefin (for example, ZEONOR (registered trademark) 1600 manufactured by Zeon Corporation, Japan: 160 °C), polyarylate (PAr: 210 °C), polysulfone (PES: 220 °C), polyimide (for example, Neoprim (registered trademark) manufactured by Mitsubishi Gas Chemical Company, Inc.: 260 °C), fluorene ring-modified polycarbonate (BCF-PC: the compound described in JP-A-2000-227603: 225 °C), alicyclic-modified polycarbonate (IP-PC: the compound described in JP-A-2000-227603: 205 °C), acryloyl compound (the compound described in JP-A-2002-80616: 300 °C or higher), etc. (the temperature in parentheses indicates Tg).

[0191] The electronic device of the present invention is an electronic device such as an organic EL element, and therefore the base material is preferably transparent. That is, the light transmittance is usually 80% or more, preferably 85% or more, and more preferably 90% or more. The light transmittance can be calculated by subtracting the diffuse transmittance from the total light transmittance measured using an integrating sphere type light transmittance measuring device by the method described in JIS K7105:1981, that is, measuring the total light transmittance and the amount of scattered light.

[0192] In addition, the base materials listed above may be unstretched films or stretched films. The base material can be manufactured by a generally known method in the past. Regarding the manufacturing method of these base materials, the matters described in paragraphs "0051" to "0055" of International Publication No. 2013 / 002026 can be appropriately adopted.

[0193] Various known treatments for improving the adhesion, such as corona discharge treatment, flame treatment, oxidation treatment, or plasma treatment, etc., can be performed on the surface of the base material, and the above treatments can also be combined as needed. In addition, an adhesion-improving treatment can also be performed on the base material.

[0194] The base material may be a single layer or a laminated structure of two or more layers. When the base material is a laminated structure of two or more layers, each base material may be of the same type or different types.

[0195] The thickness of the base material of the present invention (the total thickness when it is a laminated structure of two or more layers) is preferably 10 to 200 μm, and more preferably 20 to 150 μm.

[0196] In addition, in the case of a film substrate, a film substrate with a gas barrier layer is preferred.

[0197] The gas barrier layer for the above-mentioned film substrate may form a film of inorganic substances, organic substances, or a mixed film of both on the surface of the film substrate. Preferably, the water vapor transmission rate (25 ± 0.5 °C, relative humidity (90 ± 2)% RH) measured by the method according to JIS K 7129-1992 is 0.01 g / m 2 ·24 h or less, and more preferably, the oxygen permeability measured by the method according to JIS K 7126-1987 is 1 × 10 -3 mL / m 2 ·24 h·atm or less, and the water vapor transmission rate is 1 × 10 -3 g / m 2 ·24 h or less, which is a high gas barrier film.

[0198] As the material for forming the above gas barrier layer, any material having the function of suppressing the intrusion of materials such as moisture and oxygen that cause deterioration of the components can be used. For example, silicon monoxide, silicon dioxide, silicon nitride, silicon oxynitride, silicon carbide, carbon oxysilicon, etc. can be used.

[0199] There is no particular limitation on the gas barrier layer. For example, in the case of an inorganic gas barrier layer such as silicon monoxide, silicon dioxide, silicon nitride, silicon oxynitride, silicon carbide, carbon oxysilicon, etc., sputtering methods (such as magnetron cathode sputtering, planar magnetron sputtering, diode AC planar magnetron sputtering, diode AC rotary magnetron sputtering, etc.), evaporation methods (such as resistance heating evaporation, electron beam evaporation, ion beam evaporation, plasma-assisted evaporation, etc.), thermal CVD method, catalytic chemical vapor growth method (Cat-CVD), capacitive coupling plasma CVD method (CCP-CVD), photo-CVD method, plasma CVD method (PE-CVD), epitaxial growth method, atomic layer growth method, reactive sputtering method, and other chemical vapor deposition methods can be used to form an inorganic material layer.

[0200] Furthermore, after coating a coating solution containing an inorganic precursor such as polysilazane and tetraethyl orthosilicate (TEOS) on a support, a method of forming an inorganic gas barrier layer by performing a modification treatment such as irradiation with vacuum ultraviolet light; film metallization techniques such as metal plating on a resin substrate and bonding a metal foil to a resin substrate also form an inorganic gas barrier layer.

[0201] In addition, the inorganic gas barrier layer may also include an organic layer containing an organic polymer. That is, the inorganic gas barrier layer may be a laminate of an inorganic layer containing an inorganic material and an organic layer.

[0202] Regarding the organic layer, for example, a layer can be formed by coating an organic monomer or an organic oligomer on a resin substrate, and then, for example, polymerization and crosslinking as needed are carried out using an electron beam device, a UV light source, a discharge device, or other suitable devices. Additionally, for example, it can also be formed by forming a polymer from an organic monomer or an organic oligomer after vapor deposition of an organic monomer or an organic oligomer capable of flash evaporation and radiation crosslinking. The coating efficiency can be improved by cooling the resin substrate.

[0203] As a coating method of the organic monomer or the organic oligomer, for example, roll coating (e.g., gravure roll coating), spraying (e.g., electrostatic spraying), etc. can be cited. Additionally, as an example of a laminate of an inorganic layer and an organic layer, for example, the laminates described in International Publication No. 2012 / 003198 and International Publication No. 2011 / 013341 can be cited.

[0204] In the case of a laminate of an inorganic layer and an organic layer, the thickness of each layer can be the same or different. The thickness of the inorganic layer is preferably in the range of 3 to 1000 nm, more preferably in the range of 10 to 300 nm. The thickness of the organic layer is preferably in the range of 100 nm to 100 μm, more preferably in the range of 1 to 50 μm.

[0205] Examples

[0206] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. It should be noted that in the following examples, unless otherwise specified, the operations are carried out at room temperature (25 °C). Additionally, unless otherwise specified, "%" and "parts" respectively refer to "mass %" and "mass parts".

[0207] <Preparation of Ink Composition 1>

[0208] The solvent was removed from a 20 mass% solution of perhydropolysilazane (PHPS) in dibutyl ether (DBE) (manufactured by AZ Electronic Materials Corporation) using a vacuum dryer.

[0209] After removing the solvent, it was diluted with a highly drying solvent A and a low drying solvent B so that the concentration of perhydropolysilazane became 10 mass%. Specifically, in a nitrogen atmosphere, each solvent was added so that the mole fraction of DBE as the highly drying solvent A in all the solvents was 0.11 and the mole fraction of DEGDBE as the low drying solvent B in all the solvents was 0.89, and they were stirred well, thereby obtaining Ink Composition 1.

[0210] It should be noted that in the preparation of the ink composition 1, the weight-average molecular weight (Mw) of the polysilazane determined by conversion to polystyrene by GPC (Gel Permeation Chromatography) was 7000. The molecular weight of the polysilazane was adjusted during the synthesis of the polysilazane.

[0211] The mole fraction, vapor pressure, and P of each solvent in the obtained ink composition 1 are shown in the following table. 合计 and so on are shown in the following table.

[0212] <Preparation of Ink Compositions 2 to 39>

[0213] In the preparation of the above ink composition 1, except that the weight-average molecular weight (Mw) of PHPS, the PHPS concentration (mass%), the types of the highly drying solvent A and the low drying solvent B, and the mole fraction in each solvent were changed as shown in the following table, the ink compositions 2 to 39 were prepared in the same manner.

[0214] <Fabrication of Organic EL Element 1-1>

[0215] (1) Preparation of Substrate

[0216] As the substrate, an alkali-free glass substrate was prepared.

[0217] (2) Formation of First Electrode

[0218] On one surface of the above glass substrate, an Al film was formed as the first electrode (metal layer) under the following conditions. The thickness of the formed first electrode was 150 nm. It should be noted that the thickness of the first electrode is a value measured using a contact surface profiler (DECTAK).

[0219] For the Al film, a vacuum evaporation apparatus was used, and after reducing the pressure to a vacuum degree of 1×10 -4 Pa, it was formed using a tungsten crucible for resistance heating.

[0220] (3) Formation of Organic EL Layer

[0221] First, in each of the evaporation crucibles in the vacuum evaporation apparatus, the following materials constituting each layer of the organic functional layer were filled in the amounts most suitable for device fabrication. The evaporation crucibles used were crucibles made of a resistance heating material made of molybdenum or tungsten.

[0222] (3-1) Formation of Hole Injection Layer

[0223] After reducing the pressure to a vacuum degree of 1×10 -4 Pa, the evaporation crucible containing the following Compound A-1 was energized and heated, and it was evaporated on the first electrode (metal layer side) at an evaporation rate of 0.1 nm / second to form a hole injection layer with a thickness of 10 nm.

[0224] (3-2) Formation of the hole transport layer

[0225] Next, the evaporation crucible containing the following compound M-2 was electrically heated, and evaporation was performed on the hole injection layer at an evaporation rate of 0.1 nm / second to form a hole transport layer with a thickness of 30 nm.

[0226] (3-3) Formation of the light-emitting layer

[0227] Next, the following compound BD-1 and the following compound H-1 were co-evaporated at an evaporation rate of 0.1 nm / second so that the compound BD-1 had a concentration of 7% by mass to form a light-emitting layer (fluorescent light-emitting layer) that emitted blue light with a thickness of 15 nm.

[0228] Next, the following compound GD-1, the following compound RD-1, and the following compound H-2 were co-evaporated at an evaporation rate of 0.1 nm / second so that the compound GD-1 had a concentration of 20% by mass and the compound RD-1 had a concentration of 0.5% by mass to form a light-emitting layer (phosphorescent light-emitting layer) that emitted yellow light with a thickness of 15 nm.

[0229] (3-4) Formation of the electron transport layer

[0230] Then, the heating boat containing the following compound T-1 as the electron transport material was electrically heated to form an electron transport layer composed of Alq3 (tris(8-hydroxyquinoline)) on the light-emitting layer. At this time, the evaporation rate was set within the range of 0.1 to 0.2 nm / second, and the thickness was set to 30 nm.

[0231] (3-5) Formation of the electron injection layer (metal affinity layer)

[0232] Next, the heating boat containing the following compound I-1 as the electron injection material was electrically heated to form an electron injection layer composed of Liq on the electron transport layer. At this time, the evaporation rate was set within the range of 0.01 to 0.02 nm / second, and the thickness was set to 2 nm. It should be noted that this electron injection layer functions as a metal affinity layer.

[0233] Through the above operations, an organic EL layer that emits white light was formed.

[0234] [Chemical formula 3]

[0235]

[0236] (4) Formation of the second electrode

[0237] Furthermore, a Mg / Ag mixture (Mg:Ag = 1:9 (volume ratio)) was evaporated with a thickness of 10 nm to form the second electrode and its extraction electrode.

[0238] (5) Formation of the capping layer

[0239] Then, it is transferred to the original vacuum chamber, and α-NPD (4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl) is vapor-deposited on the second electrode at a vapor deposition rate in the range of 0.1 to 0.2 nm / second until the thickness becomes 40 nm, forming a capping layer for the purpose of improving light extraction.

[0240] (6) Formation of the first sealing layer

[0241] Next, as the first sealing layer covering the light-emitting part of the above-produced organic EL element, silicon nitride (SiN, Vickers hardness HV900) with a thickness of 500 nm is formed by plasma CVD method.

[0242] (7) Formation of the second sealing layer

[0243] Next, in a nitrogen atmosphere, the above-prepared ink composition 1 is filled into the ink cartridge integrated head of the inkjet device. Then, the organic EL element formed on the above first sealing layer is coated with the ink composition 1 by an inkjet method in a nitrogen atmosphere, and then the element is moved to a hot plate and dried at 100 °C for 5 minutes to form a second sealing layer with a thickness of 300 nm.

[0244] (8) Formation of the third sealing layer

[0245] Next, on the second sealing layer, as the third sealing layer, silicon nitride (SiN, Vickers hardness HV900) with a thickness of 500 nm is formed by plasma CVD method, obtaining the evaluation organic EL element 1-1 formed with the first to third sealing layers.

[0246] <Fabrication of organic EL elements 1-2 to 1-39>

[0247] In the fabrication of the above organic EL element 1-1, the evaluation organic EL elements 1-2 to 1-39 are fabricated in the same manner except that the ink composition 1 in the formation of the above second sealing layer is changed as shown in the following table.

[0248] [Sealing performance evaluation]

[0249] Each of the organic EL elements 1-2 to 1-39 for evaluation was placed in a thermo-hygrostat at high temperature and high humidity (temperature: 85°C, relative humidity: 85%) for an accelerated degradation test. Each organic EL element was taken out of the thermo-hygrostat at regular intervals and made to emit light at room temperature to confirm the presence or absence of dark spots (DS) during the accelerated degradation at 85°C and 85%. The time until the dark spot area ratio within the light-emitting region reached 0.5% was defined as the lifetime, and the lifetime was evaluated. The longer the lifetime, the higher the sealing performance. Grades 3 to 5 of the following evaluation criteria were set as passing.

[0250] (Evaluation Criteria)

[0251] Grade 1: Lifetime is less than 50 hours

[0252] Grade 2: Lifetime is 50 hours or more and less than 100 hours

[0253] Grade 3: Lifetime is 100 hours or more and less than 300 hours

[0254] Grade 4: Lifetime is 300 hours or more and less than 500 hours

[0255] Grade 5: Lifetime is 500 hours or more

[0256] <Fabrication of Organic EL Elements 2-1 to 2-39>

[0257] In the fabrication of the above organic EL element 1-1, instead of the above alkali-free glass substrate, a 15-μm polyimide film was used, and the thicknesses of the first sealing layer and the third sealing layer were made other than 1000 nm. Similarly, the organic EL element 2-1 for evaluation was fabricated.

[0258] In addition, in the fabrication of the organic EL element 2-1, except that the ink composition 1 during the formation of the second sealing layer was changed as shown in the following table, the organic EL elements 2-2 to 2-39 for evaluation were fabricated in the same manner.

[0259] [Flexural Resistance Evaluation]

[0260] Each of the organic EL elements 2-1 to 2-39 for evaluation was wound around a metal roller with a diameter of 10 mm and placed in a thermo-hygrostat at high temperature and high humidity (temperature: 60°C, relative humidity: 90%) for an accelerated degradation test. At this time, the polyimide film was wound in contact with the metal roller. After 1500 hours, each organic EL element was taken out of the thermo-hygrostat, and the light-emitting state (dark spot area ratio) was confirmed by microscopy at room temperature. Grades 3 to 5 of the following evaluation criteria were set as passing.

[0261] (Evaluation Criteria)

[0262] Grade 1: Peeling of the sealing layer or non-light emission

[0263] Level 2: The ratio of the area of the dark spot is 1% or more

[0264] Level 3: The ratio of the area of the dark spot is 0.5% or more and less than 1%

[0265] Level 4: The ratio of the area of the dark spot is 0.1% or more and less than 0.5%

[0266] Level 5: The ratio of the area of the dark spot is less than 0.1%

[0267]

[0268]

[0269] [Table 3]

[0270] Table III

[0271]

[0272] [Table 4]

[0273] Table IV

[0274]

[0275] As shown in the above results, it can be seen that the organic EL element having a sealing layer formed using the ink composition of the present invention has higher sealing performance, better adhesion between the sealing layer and the electronic device during bending, and excellent light-emitting performance compared with the organic EL element of the comparative example.

[0276] In addition, for the organic EL element having a sealing layer formed using the ink composition of the present invention, the foreign matter portion was determined by SEM observation (Hitachi High-Tech S4800) of the surface, and a thin film specimen of the cross section was prepared for the foreign matter portion using a FIB device (JIB-4000PLUS manufactured by JEOL). The cross section prepared was observed at a magnification of 200k using a TEM (JEM-2010F manufactured by JEOL, acceleration voltage 200 kV), and as a result, a polysilazane region was confirmed in the gap between the defect region in the first sealing layer and the first sealing layer. Therefore, it was confirmed that an organic EL element having excellent sealing performance and bending resistance can be obtained through the polysilazane region and the second sealing layer. In addition, the interval of the gap was 15 nm or less.

[0277] On the other hand, in the organic EL element of the comparative example, a void region was confirmed instead of the polysilazane region.

[0278] Industrial applicability

[0279] The present invention can be used for an ink composition for forming an electronic device sealing layer, a method for forming an electronic device sealing layer, and an electronic device sealing layer, which have excellent sealing performance and bending resistance and can suppress the deterioration of electronic devices.

[0280] Description of reference numerals

[0281] 1 Electronic device

[0282] 2 First sealing layer

[0283] 3 Second sealing layer

[0284] 4 Foreign matter

[0285] 5 Abnormally grown part

[0286] 6 Defect area

[0287] 7 Gap (polysilazane region)

Claims

1. An ink composition for forming a sealing layer of an electronic device, which contains polysilazane, The ink composition contains at least one type of highly volatile solvent A with a vapor pressure of 8.0×10 2 Pa or more at 20°C, and at least one type of low-volatility solvent B with a vapor pressure of 4.0×10 2 Pa or less, respectively. Let the mole fraction of the highly drying solvent A relative to the total amount of solvents be m a1 , m a2 , …, let the mole fraction of the lowly drying solvent B relative to the total amount of solvents be m b1 , m b2 , …, let the vapor pressure of the highly drying solvent A be P a1 , P a2 , …, let the vapor pressure of the lowly drying solvent B be P b1 , P b2 , …, when P represented by the following formula (i) 合计 is in the range of 0.5×10 2 to 3.6×10 2 Pa (Formula i) P 合计 = P a1 × m a1 + P a2 × m a2 + …, + P b1 × m b1 + P b2 × m b2 + …。 2. The ink composition for forming an electronic device sealing layer according to claim 1, wherein, The highly drying solvent A is dibutyl ether.

3. The ink composition for forming an electronic device sealing layer according to claim 1 or 2, wherein, The low drying solvent B is decalin.

4. A method for forming a sealing layer of an electronic device, which is a method for forming a sealing layer using the ink composition for forming a sealing layer of an electronic device according to any one of claims 1 to 3, and includes: A step of forming a first sealing layer on the electronic device by a vapor phase method; and A step of forming a second sealing layer by coating the ink composition for forming a sealing layer of the electronic device on the first sealing layer.

5. The method for forming a sealing layer of an electronic device according to claim 4, which includes: a step of forming a third sealing layer on the second sealing layer by a vapor phase method.

6. The method for forming an electronic device sealing layer according to claim 4 or 5, wherein, The step of forming the second sealing layer uses an inkjet method.

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