WO2021124802A1 - Ink composition for forming electronic device sealing layer, method for forming electronic device sealing layer, and electronic device sealing layer - Google Patents

Abstract

This ink composition for forming an electronic device sealing layer contains polysilazane, and the ink composition contains at least one type of each of a high-drying solvent A having a vapor pressure at 20°C of 8.0×102 Pa or higher and a low-drying solvent B having a vapor pressure at 20°C of 4.0×102 Pa or lower, Ptotal represented by formula (i) being within the range of 0.5×102-3.6×102 Pa, where ma1, ma2, . . . is the mole fraction of the high-drying solvent A with respect to the total quantity of solvent, mb1, mb2, . . . is the mole fraction of the low-drying solvent B, Pa1, Pa2, . . . is the vapor pressure of the high-drying solvent A, and Pb1, Pb2, . . . is the vapor pressure of the low-drying solvent B.　(Equation 1) Ptotal = Pa1 × ma1 + Pa2 × ma2 + . . ., Pb1 × m b1 + P b2 × mb2+ . . .

Description

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

The present invention relates to an ink composition for forming an electronic device encapsulating layer, an electronic device encapsulating layer forming method, and an electronic device encapsulating layer, and particularly excellent in encapsulation performance and bending resistance and suppresses deterioration of the electronic device. The present invention relates to an ink composition for forming an electronic device encapsulating layer and the like.

Electronic devices, particularly organic electroluminescence devices (hereinafter, also referred to as "organic EL devices" or "organic EL elements"), are organic EL elements in order to prevent the organic materials and electrodes used from being deteriorated by moisture. It has been proposed to cover the surface of the OLED with a sealing layer.

As a technique for sealing the organic EL element, for example, in the technique described in Patent Document 1, a first protective film formed on the surface of the organic EL element by a dry method (CVD method) so as to cover the organic EL element. Disclosed is an organic EL device formed on the surface of the first protective film by a wet method and provided with a second protective film for filling a non-adhered portion of the first protective film. There is. It is also described that polysilazane is used as the second protective film.
However, in the organic EL device described in Patent Document 1, the interfacial adhesion between the first protective film and the second protective film deteriorates under high temperature and high humidity of 85 ° C. and 85% RH of 100 hours or more. There was a problem of moisture permeation at the interface between the first protective film (presumably) and the second protective film, and the sealing performance was inferior.
Further, when inkjet is used for patterning the second protective film, when the inkjet method is applied to the composition disclosed in Patent Document 1, there are problems in ink ejection property and patterning accuracy. Further, grain boundaries of the second protective film formed by the inkjet printing method were generated, and the problem of water permeation at the interface was remarkable.

On the other hand, in Patent Document 2, a composition for forming a silica film containing a silicon-containing polymer and a mixed solvent containing at least two kinds of solvents, and the mixed solvent has a surface tension of 5 to 35 nN / m at 25 ° C. Is disclosed.
Further, in Patent Document 3, in a coating liquid containing polysilazane, oxygen atoms are introduced into the polysilazane and a part of the polysilazane, and the atomic composition ratio (O) of the oxygen (O) atom to the silicon (Si) atom is (O). A coating liquid containing polysilazane oxide in which / Si) is in the range of 0.01 to 0.1 is disclosed.

However, when the composition described in Patent Document 2 or the coating liquid described in Patent Document 3 is used and coated on the CVD layer by the vapor phase method by inkjet to form a sealing layer, the ink ejection property is improved. However, there was a problem of moisture permeation at the interface between the CVD layer and the coating film on the CVD layer. In addition, there is a problem that the adhesion of the interface at the time of bending is also lowered.

Japanese Unexamined Patent Publication No. 2005-056587 Japanese Unexamined Patent Publication No. 2017-031040 Japanese Unexamined Patent Publication No. 2019-036517

The present invention has been made in view of the above problems and situations, and the problem to be solved is an ink for forming an electronic device sealing layer, which is excellent in sealing performance and bending resistance and can suppress deterioration of an electronic device. The present invention provides a composition, a method for forming an electronic device sealing layer, and an electronic device sealing layer.

In order to solve the above problems, the present inventor contains polysilazane, a high-drying solvent A and a low-drying solvent B, and the mole fraction of each solvent in the process of examining the cause of the above problem. By using an ink composition in which the sum of the products of the vapor pressures of each solvent is defined in a specific range for forming a sealing layer, it is possible to have excellent sealing performance and bending resistance and suppress deterioration of electronic devices. I found it and came up with the present invention.
That is, the above-mentioned problem according to the present invention is solved by the following means.

1. 1. An ink composition for forming an electronic device encapsulating layer.
Contains polysilazane,
The ink composition contains at least one kind of a high drying solvent A having a vapor pressure of 8.0 × 10 ² Pa or more and a low drying solvent B having a ^{vapor pressure of 4.0 × 10 2 Pa or less at 20 ° C.} Contains more
The mole fraction of the highly dry solvent A with respect to the total amount of the solvent is m _a1 , m _a2 , ..., And the mole fraction of the low dry solvent B is m _b1 , m _b2 , .... When the vapor pressures are P _a1 , P _a2 , ... And the vapor pressures of the low-drying solvent B are P _b1 , P _{b2 , ..., P total} represented by the following formula (i) is 0.5 ×. An ink composition for forming an electronic device encapsulating layer in the range of 10 ² to 3.6 × 10 ^{2 Pa.}
(Equation i) P _total = P _a1 × _ma1 ＋ P _a2 × _ma2 ＋…, P _b1 × m _b1 ＋ P _b2 × m _b2 ＋…

2. The ink composition for forming an electronic device encapsulating layer according to item 1, wherein the highly dry solvent A is dibutyl ether.

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

4. A method of forming a sealing layer using the ink composition for forming an electronic device sealing layer according to any one of items 1 to 3.
The process of forming the first sealing layer on the electronic device by the vapor phase method,
A method for forming an electronic device encapsulation layer, comprising a step of forming a second encapsulation layer by applying an ink composition for forming the electronic device encapsulation layer on the first encapsulation layer.

5. The method for forming an electronic device encapsulation layer according to item 4, further comprising a step of forming a third encapsulation layer on the second encapsulation layer by a vapor phase method.

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

7. An electronic device sealing layer that seals an electronic device.
A first sealing layer containing silicon nitride, silicon oxide or silicon oxynitride,
Defect areas mixed in the first sealing layer and
A second sealing layer provided adjacent to the first sealing layer and containing polysilazane,
An electronic device sealing layer having a polysilazane region provided in a gap between the defect region and the first sealing layer and filled with polysilazane.

8. Item 2. The electronic device encapsulating layer according to Item 7, wherein the gap between the gaps is 15 nm or less when the cross section is observed using an electron microscope.

By the above means of the present invention, an ink composition for forming an electronic device sealing layer, an electronic device sealing layer forming method, and an electronic device sealing, which are excellent in sealing performance and bending resistance and can suppress deterioration of an electronic device. Layers can be provided.
Although the mechanism of expression or mechanism of action of the effect of the present invention has not been clarified, it is inferred as follows.
An ink composition containing polysilazane, a high-drying solvent A and a low-drying solvent B, and in which the sum of the mole fraction of each solvent and the product of the vapor pressure of each solvent is defined in a specific range is applied to the sealing layer. When used for formation, there is a difference in the drying rate between the high-drying solvent A and the low-drying solvent B in the process of drying the solvent. Due to the difference in drying rate between the high-drying solvent A and the low-drying solvent B, the high-drying solvent A is pinned by being dried first, and the lower layer (first sealing layer) formed by the vapor phase method is formed. It is presumed that it contributes to the stable adhesion of the solvent. Further, it is presumed that the interface becomes stronger due to the adhesion to the lower layer, so that the moisture diffusion at the interface is suppressed and the deterioration of the electronic device due to the moisture passing through the interface is prevented.
Further, by containing the low-drying solvent B, the ink ejection property and the patterning accuracy are excellent even when the inkjet method is used.

The figure which showed the cross-sectional image of the electronic device sealing layer of this invention (electron micrograph)

The ink composition for forming an electronic device sealing layer of the present invention is an ink composition for forming an electronic device sealing layer, which contains polysilazane, and the ink composition has a vapor pressure of 8 at 20 ° C. The highly dry solvent A containing at least one of the highly dry solvent A of 0.0 × 10 ^{2 Pa or more and the low dry solvent B of 4.0 × 10 2} Pa or less each contain the above-mentioned highly dry solvent A with respect to the total amount of the solvent. The mole fraction is _ma1 , _ma2 , ..., The mole fraction of the low-drying solvent B is m _b1 , m _b2 , ..., And the vapor pressure of the high-drying solvent A is P _a1 , P _a2 , ... When the vapor pressure of the low-drying solvent B is P _b1 , P _{b2 , ..., The P total} represented by the following formula (i) is 0.5 × 10 ² to 3.6 × 10 ² Pa. Is within the range of.
(Equation i) P _total = P _a1 × _ma1 ＋ P _a2 × _ma2 ＋…, P _b1 × m _b1 ＋ P _b2 × m _b2 ＋…
This feature is a technical feature common to or corresponding to each of the following embodiments.

In an embodiment of the present invention, it is preferable that the highly dry solvent A is dibutyl ether from the viewpoint of solubility of polysilazane, and it is appropriate that the low dry solvent B is decalin. It is preferable in that dischargeability and patterning property can be obtained.

The method for forming an electronic device sealing layer of the present invention is a method for forming a sealing layer using the ink composition for forming the electronic device sealing layer, and the first sealing is performed on the electronic device by the vapor phase method. It includes a step of forming a stop layer and a step of forming a second sealing layer by applying the electronic device sealing layer forming ink on the first sealing layer.
As a result, the high-drying solvent A is pinned by being dried first due to the difference in drying speed between the high-drying solvent A and the low-drying solvent B contained in the ink composition, and is formed by the vapor phase method. The adhesiveness between the first sealing layer and the second sealing layer is excellent, and the sealing performance and bending resistance are excellent.
Further, since the interface is strengthened by the adhesion between the first sealing layer and the second sealing layer, the diffusion of water at the interface can be suppressed, and the deterioration of the electronic device due to the water passing through the interface can be suppressed.

Further, it is preferable to provide a step of forming the third sealing layer on the second sealing layer by the vapor phase method from the viewpoint of excellent sealing performance.
It is preferable to use an inkjet method for the step of forming the second sealing layer because the layer can be formed with high accuracy.

The electronic device encapsulation layer of the present invention has a first encapsulation layer containing silicon nitride, silicon oxide or silicon oxynitride, a defect region mixed in the first encapsulation layer, and adjacent to the first encapsulation layer. It has a second sealing layer containing polysilazane and a polysilazane region filled in a gap between the defect region and the first sealing layer.
As a result, the polysilazane region filled in the gap between the defect region and the first sealing layer provides excellent adhesion between the first sealing layer and the second sealing layer, and is excellent in sealing performance and bending resistance. .. Further, since the interface is strengthened by the adhesion between the first sealing layer and the second sealing layer, the diffusion of water at the interface can be suppressed, and the deterioration of the electronic device due to the water passing through the interface can be suppressed.

It is preferable that the gap between the gaps is 15 nm or less when the cross section is observed using an electron microscope, because a superior effect can be obtained as compared with the conventional ink.

Hereinafter, the present invention, its constituent elements, and modes and modes for carrying out the present invention will be described. In the present application, "-" is used to mean that the numerical values described before and after the value are included as the lower limit value and the upper limit value.

[Outline of Ink Composition for Forming Electronic Device Encapsulating Layer of the Present Invention]
The ink composition for forming an electronic device encapsulating layer of the present invention (hereinafter, also simply referred to as an ink composition) is an ink composition for forming an electronic device encapsulating layer, which contains polysilazane and has the ink composition. The product contains at least one or more of a high-drying solvent A having a vapor pressure of 8.0 × 10 ² Pa or more and a low-drying solvent B having a ^{vapor pressure of 4.0 × 10 2 Pa or less at 20 ° C.} The molar proportions of the highly dry solvent A with respect to the total amount of the solvent are m _a1 , _ma2 , ..., And the molar proportions of the low dry solvent B are m _b1 , m _b2 , ... When the vapor pressures of the _{low-drying solvent B are P a1} , P _a2 , ... And the vapor pressures of the low-drying solvent B are P _b1 , P _{b2 , ..., P total} represented by the following formula (i) is 0.5. It is in the range of × 10 ² to 3.6 × 10 ^{2 Pa.}
(Equation i) P _total = P _a1 × _ma1 ＋ P _a2 × _ma2 ＋…, P _b1 × m _b1 ＋ P _b2 × m _b2 ＋…

Here, the "electronic device" in the present invention refers to an element that generates, amplifies, converts, or controls an electric signal by utilizing the kinetic energy, potential energy, etc. of an electron. For example, active elements such as light emitting diode elements, organic electroluminescence elements, photoelectric conversion elements and transistors can be mentioned. Further, in the present invention, a passive element that performs passive work such as "resisting" and "storing" in response to an action from others, such as a resistor and a capacitor, is also included in the electronic device.
Therefore, the ink composition of the present invention is used to form a sealing layer for sealing the electronic device described above.

<Highly dry solvent A>
The highly dry solvent A according to the present invention has a vapor pressure of 8.0 × 10 ² Pa or more at 20 ° C. and an upper limit of 2.0 × 10 ⁴ Pa or less.
In order to solve the problem of the present invention, ^{it is necessary to have 8.0 × 10 2} Pa or more in order to obtain an appropriate drying rate, and the stability against composition change due to natural drying before ink ejection or during ink ejection is required. It needs to be 2.0 × 10 ⁴ Pa or less to obtain.

The vapor pressure (Pa) of the highly dry solvent A according to the present invention at 20 ° C. can be determined according to the following method. For example, a lead method based on JIS K2258-1: 2009, a triple expansion method based on JIS K2258-2: 2009, and the like can be mentioned. Further, a static method, a boiling point method, an isoteniscope, a gas flow method, and a DSC method, which are known as general methods for measuring vapor pressure, can also be applied. Furthermore, it is also possible to utilize the vapor pressure data described in publicly known documents, for example, "New Edition Solvent Pocket Book" (edited by the Church of Synthetic Organic Chemistry, Ohmsha).

The highly dry solvent A having a vapor pressure of 8.0 × 10 ² Pa or more is not particularly limited as long as it does not react with polysilazane, and known ones can be used as appropriate. Specific examples thereof include aromatic solvents, alcan solvents, ester solvents, ether solvents, ketone solvents, amide solvents, and other solvents. For example, xylene, ethylene glycol monomethyl ether (also known as methyl cellosolve), isopentyl acetate (also known as isoamyl acetate), dibutyl ether (DBE), chlorobenzene, normal-butyl acetate, methyl-normal-butyl ketone, tetrachloroethylene (also known as:: Parkrolethylene), isobutyl acetate, methylisobutylketone, normal-propyl acetate, toluene, 1,4-dioxane, isopropyl alcohol, trimethylpentane (TMP), isopropyl acetate, trichloroethylene, 1,2-dichloroethane (also known as dichloride) Ethyl acetate), ethyl acetate, methyl ethyl ketone, carbon tetrachloride, 1,1,1-trichloroethane, normal hexane, tetrahydrofuran and the like. Among these, DBE and xylene are preferable, and one type may be used or a plurality of types may be used.

<Low drying solvent B>
The low-drying solvent B according to the present invention has a vapor pressure of 4.0 × 10 ² Pa or less at 20 ° C., and has a lower limit of 1.0 × 10 ^-1 Pa or more.
^{In order to solve the problem of the present invention, it is necessary to be 4.0 × 10 2} Pa or less in order to obtain an appropriate drying rate, and in order to obtain a drying property for removing a solvent after coating film, 1.0 × It ^{must be 10 -1} Pa or more.
As a method for measuring the vapor pressure (Pa) of the low-drying solvent B at 20 ° C., the same method as the above-mentioned method for measuring the vapor pressure of the high-drying solvent A can be adopted.

The low-drying solvent B having a vapor pressure of 4.0 × 10 ² Pa or less is not particularly limited as long as it is a solvent that does not react with polysilazane, and a known solvent can be used as appropriate. Examples thereof include aromatic solvents, alcan solvents, ester solvents, ether solvents, ketone solvents, amide solvents, and other solvents. For example, hexadecane, diethylene glycol dibutyl ether (DEGDBE), diphenyl ether, ethylene glycol, 1-methylnaphthylene, 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 mono-normal-butyl ether (also known as butyl cellosolve), n-butylbenzene, cyclohexyl acetate, 1 , 2-Dichlorobenzene, ethylene glycol monoethyl ether acetate (also known as cellosolve acetate), methylcyclohexanol, phenetol, sec-butylbenzene, tert-butylbenzene, decalin (also known as decahydronaphthalene), 1,3,5- Examples thereof include trimethylbenzene (mesitylene), diethylene glycol dimethyl ether, N, N-dimethylformamide, methylcyclohexanone, ethylene glycol monophenyl ether (EGMPE) and the like. Among these, decalin, DEGDBE, and tetralin are preferable, and one type may be used, or a plurality of types may be used.

In the ink composition of the present invention, the mole fraction of the high-drying solvent A is set to m _a1 , m _a2 , ... With respect to the total amount of the solvent, and the mole fraction of the low-drying solvent B is set to m _b1 , m _b2 , ... the vapor pressure of the drying solvent a and P _a1, P _a2, ... an, when the vapor pressure of the low drying solvent B was P _b1, P _b2, ... and, P _total represented by the following formula (i) is, It is in the range of 0.5 × 10 ² to 3.6 × 10 ² Pa, and more preferably in the range of 1.4 × 10 ² to 3.4 × 10 ² Pa.
(Equation i) P _total = P _a1 × _ma1 ＋ P _a2 × _ma2 ＋…, P _b1 × m _b1 ＋ P _b2 × m _b2 ＋…

The mole fractions of the high-drying solvent A and the low-drying solvent B are not particularly limited as long as the formula (i) is satisfied, but for example, the molar fraction of the high-drying solvent A is 5. The mole fraction of the low-drying solvent B is preferably in the range of 95 to 60 within the range of ~ 40.

<Polysilazane>
The "polysilazane" used in the present invention is a polymer having a silicon-nitrogen bond in its structure and is a precursor of silicon nitride, and a polymer having the structure of the following general formula (1) is preferably used. ..

In the formula, R ¹ , R ² , and R ³ 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, respectively.

^{In the present invention, perhydropolysilazane in which all of R 1} , R ² and R ³ are hydrogen atoms is particularly preferable from the viewpoint of the denseness of the obtained sealing layer.

Further, the polysilazane used in the present invention preferably has a weight average molecular weight Mw of 1000 or more, more preferably 3000 or more, and particularly preferably 7000 or more. Further, it is preferable that such a high molecular weight polysilazane is contained in an amount of 50% by mass or more based on the total polysilazane. By containing the high molecular weight polysilazane, the viscosity of the ink composition can be adjusted.
As the polysilazane having an Mw of 3000 or more, for example, a polysilazane having only a high molecular weight component having a weight average molecular weight Mw of 3000 or more can be obtained by referring to the method described in Japanese Patent No. 5172867.

As the polysilazane used in the present invention, those commercially available in the state of a solution dissolved in an organic solvent can be used.
The organic solvent is not particularly limited as long as it can dissolve polysilazane, but does not contain water and a reactive group (for example, a hydroxy group or an amine group) that easily reacts with polysilazane, and is resistant to polysilazane. An inert organic solvent is preferred, and an aprotic organic solvent is more preferred.
Specifically, as the solvent, an aproton solvent; for example, carbonization of aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons such as pentane, hexane, cyclohexane, toluene, xylene, sorbesso, turpen and the like. Hydrogen solvent; Halogen hydrocarbon solvent such as methylene chloride and trichloroethane; Esters such as ethyl acetate and butyl acetate; Ketones such as acetone and methyl ethyl ketone; Aliphatic ethers such as dibutyl ether, dioxane and tetrahydrofuran, alicyclic ether and the like Ethers: Examples thereof include tetrahydrofuran, dibutyl ether, mono- and polyalkylene glycol dialkyl ethers (diglimes). The solvent is selected according to the purpose such as the solubility of polysilazane and the evaporation rate of the solvent, and may be used alone or in the form of a mixture of two or more kinds.
Further, the polysilazane raw solution in which polysilazane is dissolved in an organic solvent may be catalyst-free or may contain a catalyst.
As the catalyst, a basic catalyst is preferable, and in particular, N, N-diethylethanolamine, N, N-dimethylethanolamine, triethanolamine, triethylamine, 3-morpholinopropylamine, N, N, N', N'- Amine catalysts such as tetramethyl-1,3-diaminopropane, N, N, N', N'-tetramethyl-1,6-diaminohexane, Pt compounds such as Pt acetylacetonate, and Pd compounds such as propionic acid Pd. , Metal catalysts such as Rh compounds such as Rh acetylacetonate, and N-heterocyclic compounds. Of these, it is preferable to use an amine catalyst. The concentration of the catalyst to be added at this time is preferably in the range of 0.1 to 5% by mass, more preferably in the range of 0.5 to 2% by mass, based on the silicon compound. By setting the amount of the catalyst added within this range, it is possible to avoid excessive silanol formation, a decrease in the film density, an increase in film defects, and the like due to the rapid progress of the reaction. In addition, by adding these catalysts, the oxidation of polysilazane proceeds with a smaller amount of water.
Examples of commercially available products of the polysilazane solution include NN120-20, NAX120-20, and NL120-20 manufactured by AZ Electronic Materials Co., Ltd.

In addition, for details of polysilazane, paragraphs "0024" to "0040" of JP2013-255910A, paragraphs "0037" to "0043" of JP2013-188942A, and JP2013-2013, which are conventionally known. Paragraphs "0014" to "0021" of Japanese Patent Application Laid-Open No. 151123, paragraphs "0033" to "0045" of Japanese Patent Application Laid-Open No. 2013-052569, paragraphs "0062" to "0075" of JP-A-2013-129557, Japanese Patent Application Laid-Open No. 2013 -226758 It can be adopted by referring to paragraphs "0037" to "0064" of the publication.

The viscosity of the ink composition of the present invention is preferably in the range of 1 to 20 mPa · s at 20 ° C. because it has an appropriate viscosity and the ejection stability by the inkjet method is good.
The viscosity can be measured by a commercially available rotary or vibration viscometer.

Further, it is preferable that the ink composition of the present invention contains a volatile thickener because the viscosity of the ink composition can be adjusted.
As a volatile thickener, a liquid compound having volatileness that does not inhibit the film formation of the ink composition and having a viscosity at 20 ° C. of about 1 mPa · s or more, or a liquid compound having a viscosity of about 1 mPa · s or more when mixed, or 1 mPa · s or more by mixing. It is not particularly limited as long as it is a liquid mixture having a viscosity, but it is an aproton that is compatible with the above-mentioned high-drying solvent A, low-drying solvent B and polysilazane and does not have reactivity with polysilazane. Water-insoluble volatile oils and glycol ethers, which are highly soluble and have low water solubility, are preferred.
Specifically, the volatile oils include, for example, terepine, petrol, mineral spirit, α-pinene, isoparaffin, and volatile silicone oils, and the glycol ethers include, for example, diethylene glycol dibutyl ether (DEGDBE) and tripropylene glycol dimethyl ether. , Diethylene glycol butyl methyl ether, dipropylene glycol dimethyl ether, etc. Among them, compounds having appropriate viscosity, volatility and water insolubility such as diethylene glycol dibutyl ether and volatile silicone oil can also be used as a diluting solvent. It is preferable in that it can be done.

The ink composition of the present invention can be obtained by adding a high-drying solvent A and a low-drying solvent B to a polysilazane raw solution dissolved in the above organic solvent so as to have a predetermined mole fraction.

Further, it is preferable to add the volatile thickener to the polysilazane original solution in addition to the highly dry solvent A and the low dry solvent B.
It is preferable to stir during and after the addition of the high-drying solvent A, the low-drying solvent B and the volatile thickener, and further, it is preferable to heat and stir. The heating temperature is preferably equal to or lower than the boiling point of the high-drying solvent A and the low-drying solvent B, and more preferably in the range of 50 to 120 ° C. The heating means and the stirring means are not particularly limited, and a general method for heating and stirring the solution can be applied, but when heating, the container or the kettle containing the solution is indirectly heated. The method of heating the liquid with is preferable. Further, in the case of stirring, a method of rotating a shaft to which a stirring blade is attached by a motor, a method of stirring using a stirrer and a stirrer if the amount of liquid is small, and the like can be applied.
Further, in order to stabilize (defoam) the coating liquid, it is preferable to heat, stir or ultrasonically disperse it.

The ink composition of the present invention can be a stable ink composition without bubbles when the amount of increase (ΔV) of the dissolved gas amount after the elapsed time is ΔV <100 ppm / day. It is preferable in that it can be done. Further, ΔV <10 ppm / day is more preferable, and ΔV <1 ppm / day is particularly preferable.
The method for measuring the amount of dissolved gas is, for example, to identify the gas by collecting the gas generated after heating, stirring or ultrasonically dispersing the ink composition, and combining GC / MS and a detector suitable for the gas to be detected. And quantification is possible. In addition, since it is known that ammonia gas and silane gas are the gases that are generated in the oxidation reaction of polysilazane and may be dissolved in the coating liquid, gas detector tubes and gas detectors according to the target gas are used. It is also possible to quantify the amount generated using this and estimate the total amount as the amount of dissolved gas.

[Method for forming an electronic device encapsulation layer]
The method for forming an electronic device encapsulating layer of the present invention is a method for forming an encapsulating layer using the above-mentioned ink composition of the present invention, and a first encapsulating layer is formed on an electronic device by a vapor phase method. A step of forming a second sealing layer by applying the ink composition onto the first sealing layer is provided.
Further, it is preferable to provide a step of forming the third sealing layer on the second sealing layer by the vapor phase method in that the sealing performance of the electronic device can be further improved.

<First sealing layer forming step>
In the first sealing layer forming step, the first sealing layer is formed on the electronic device by the vapor phase method.
The vapor phase method includes a sputtering method (including a reactive sputtering method such as magnetron cathode sputtering, flat plate magnetron sputtering, bipolar AC flat plate magnetron sputtering, and bipolar AC rotating magnetron sputtering), and a vapor deposition method (for example, resistance heating). Vapor deposition, electron beam vapor deposition, ion beam vapor deposition, plasma-assisted vapor deposition, etc.), thermal CVD method, catalytic chemical vapor deposition method (Cat-CVD), capacitive coupling plasma CVD method (CCP-CVD), optical CVD method, plasma CVD method. (PE-CVD), an epitaxial growth method, a chemical vapor deposition method such as an atomic layer growth method, and the like can be mentioned. Above all, it is preferably formed by the CVD method.
The first sealing layer contains silicon nitride (SiN), silicon oxide (silicon monoxide, silicon dioxide, etc.) or silicon oxynitride.
The thickness of the first sealing layer is preferably in the range of, for example, 10 to 1000 nm, and more preferably in the range of 100 to 500 nm.

<Second sealing layer forming step>
In the second sealing layer forming step, the second sealing layer is formed by applying the above-mentioned ink composition of the present invention on the first sealing layer.
Specifically, it is preferable to further perform a drying step of applying the ink composition on the first sealing layer (coating step) and drying the obtained coating film, and after the drying step, obtain the ink composition. It may have a step of irradiating the coated film with vacuum ultraviolet rays in a nitrogen atmosphere to modify it.

(Applying process)
Any suitable method can be adopted as the coating method of the ink composition, for example, spin coating method, roll coating method, flow coating method, inkjet method, spray coating method, printing method, dip coating method, flow. Examples include a spread film forming method, a bar coating method, and a gravure printing method. Above all, it is preferable to use the inkjet method in that fine patterning required when encapsulating an electronic device such as an organic EL element can be performed on demand.

As the inkjet method, a known method can be used.
The inkjet method is roughly divided into a drop-on-demand method and a continuous method, both of which can be used. The drop-on-demand method includes an electric-mechanical conversion method (for example, single cavity type, double cavity type, bender type, piston type, shared mode type, shared wall type, etc.) and an electric-heat conversion method (for example, thermal). There are an inkjet type, a bubble jet (registered trademark) type, etc.), an electrostatic attraction method (for example, an electric field control type, a slit jet type, etc.) and a discharge method (for example, a spark jet type, etc.). From the viewpoint of cost and productivity of the inkjet head, it is preferable to use an electric-mechanical conversion method or an electric-heat conversion method head. A method of dropping droplets (for example, a coating liquid) by an inkjet method may be called an "inkjet method".

When applying the ink composition, it is preferable to apply it in a nitrogen atmosphere.

(Drying process)
In the drying step, the solvent contained in the coating film (solvent containing high drying solvent A, low drying solvent B, etc.) is dried by drying the coating film obtained by coating with the ink composition. Remove.
The drying step is also preferably performed in a nitrogen atmosphere. The drying method shall be adopted with reference to the conventionally known paragraphs "0058" to "0064" of JP-A-2014-151571, paragraphs "0052" to "0056" of JP-A-2011-183773, and the like. Can be done.

(Modification process)
The modification treatment step may include a step of irradiating the obtained coating film with vacuum ultraviolet rays in a nitrogen atmosphere after the drying step to perform the modification treatment.
The reforming treatment refers to a conversion reaction of polysilazane to silicon oxide or silicon nitride. Similarly, the reforming treatment is performed under a nitrogen atmosphere such as in a glove box or under reduced pressure.
For the modification treatment in the present invention, a known method based on the conversion reaction of polysilazane can be selected. In the present invention, a conversion reaction using plasma, ozone, or ultraviolet rays, which can be converted at a low temperature, is preferable. Conventionally known methods can be used for plasma and ozone. In the present invention, it is preferable to form the second sealing layer of the present invention by providing the coating film and irradiating it with vacuum ultraviolet light (also referred to as VUV) having a wavelength of 200 nm or less for modification treatment.

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.
Of the second sealing layer, the entire layer may be modified, but the thickness of the modified layer after modification is preferably in the range of 1 to 50 nm, and is preferably 1 to 30 nm. Within the range is more preferred.

In the step of irradiating the vacuum ultraviolet rays for the modification treatment, the illuminance of the vacuum ultraviolet rays on the coating film surface received by the coating film ^{is preferably in the range of 30 to 200 mW / cm 2} , and is preferably 50 to 160 mW / cm ^2. It is more preferable that it is within the range of. By setting the illuminance of the vacuum ultraviolet rays to 30 mW / cm ² or more, the reforming efficiency can be sufficiently improved, and when it is 200 mW / cm ² or less, the damage occurrence rate to the coating film is extremely suppressed, and the substrate can be used. It is preferable because it can also reduce the damage of the illuminance.

For vacuum ultraviolet irradiation, the amount of vacuum ultraviolet irradiation energy on the coating film surface ^{is preferably in the range of 1 to 10 J / cm 2} , and from the viewpoint of barrier properties and moist heat resistance for maintaining the desiccant function, 3 More preferably, it is in the range of about 7 J / cm ^2.

A rare gas excimer lamp is preferably used as a light source for vacuum ultraviolet rays. Since vacuum ultraviolet light is absorbed by oxygen, the efficiency in the vacuum ultraviolet irradiation step tends to decrease. Therefore, it is preferable to irradiate vacuum ultraviolet light in a state where the oxygen concentration is as low as possible. That is, the oxygen concentration during 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. Is within the range of.

The reforming treatment can also be performed in combination with the heat treatment. The heating conditions are preferably in the range of 50 to 300 ° C., more preferably in the range of 60 to 150 ° C., preferably in combination with heat treatment for 1 second to 60 minutes, more preferably 10 seconds to 10 minutes. By doing so, the dehydration condensation reaction at the time of modification can be promoted, and the modified product can be formed more efficiently.

Examples of the heat treatment include a method of contacting a base material with a heating element such as a heat block to heat the coating film by heat conduction, a method of heating the atmosphere with an external heater using a resistance wire or the like, and an infrared region such as an IR heater. A method using the light of the above can be mentioned, but the method is not particularly limited. Further, a method capable of maintaining the smoothness of the coating film containing the silicon compound may be appropriately selected.

<Third sealing layer forming step>
In the third sealing layer forming step, the third sealing layer is formed on the second sealing layer by the vapor phase method.
The vapor phase method is the same as the vapor phase method used in the first sealing layer forming step, such as a sputtering method (for example, magnetron cathode sputtering, flat plate magnetron sputtering, bipolar AC flat plate magnetron sputtering, bipolar AC rotary magnetron sputtering, etc.). , Including reactive sputtering method), vapor deposition method (for example, resistance heating vapor deposition, electron beam deposition, ion beam vapor deposition, plasma-assisted vapor deposition, etc.), thermal CVD method, catalytic chemical vapor deposition method (Cat-CVD), capacity. Examples thereof include a combined plasma CVD method (CCP-CVD), an optical CVD method, a plasma CVD method (PE-CVD), an epitaxial growth method, a chemical vapor deposition method such as an atomic layer growth method, and the like. Above all, it is preferably formed by the CVD method.
The third sealing layer contains silicon nitride (SiN), silicon oxide (silicon monoxide, silicon dioxide, etc.) or silicon oxynitride.
The thickness of the third sealing layer is preferably in the range of, for example, 10 to 1000 nm, and more preferably in the range of 100 to 500 nm.

<Determination that the second sealing layer is derived from polysilazane>
In the second sealing layer according to the present invention, it is preferable to form polysilazane as a precursor, particularly preferably perhydropolysilazane, but the final finished second sealing layer is made of polysilazane. The formed layer can be demonstrated by analysis by the following method.

In the present invention, an example in which perhydropolysilazane is applied as polysilazane will be described.

When the general composition of commercially available perhydropolysilazane is SiN _v H _w , v is 0.78 to 0.80. The precursor layer formed from perhydropolysilazane takes in water and oxygen in the forming atmosphere and releases ammonia and hydrogen, and the composition changes as shown by the following formulas (A) and (B).

In the process, one nitrogen is released, while three oxygens are taken in. This also applies when the above-mentioned various reforming treatments are performed. Therefore, when the composition of the second sealing layer coated and formed from perhydropolysilazane _{is shown by SiO x} N _y , the relationship between x and y follows the following formula (C).

Equation (C)
y = 0.8-x / 3, x ≧ 0, y ≧ 0,
When the original composition is SiN _0.8 H _w , when the composition distribution in the thickness direction of the layer coated and formed from perhydropolysilazane is analyzed by XPS, all the compositions at each measurement point in the thickness direction are as described above. That would be the case (there is a few percent error).

Therefore, when the composition distribution of the Si-containing layer in the thickness direction is analyzed and _{indicated by SiO x} N _y , it is 80% or more of the thickness of the formed second sealing layer. If the composition of the measurement point is in the range of ± 2% of the value of y (0.8-x / 3), it is estimated that the membrane is a sealing layer formed from perhydropolysilazane. Is possible.

[Electronic device sealing layer]
The electronic device encapsulation layer of the present invention has a first encapsulation layer containing silicon nitride, silicon oxide or silicon oxynitride, a defect region mixed in the first encapsulation layer, and adjacent to the first encapsulation layer. It has a second sealing layer containing polysilazane and a polysilazane region provided in a gap between the defect region and the first sealing layer and filled with polysilazane.
The electronic device sealing layer of the present invention is formed by the method for forming an electronic device sealing layer. That is, the second sealing layer and the polysilazane region are formed by using the ink composition of the present invention described above.
Further, in the electronic device encapsulation layer of the present invention, a third encapsulation layer formed by a vapor phase method may be further provided on the second encapsulation layer.

<First sealing layer>
The first sealing layer is a layer formed on the electronic device by the vapor phase method described above. Specifically, it contains silicon nitride (SiN), silicon oxide (silicon monoxide, silicon dioxide, etc.) or silicon oxynitride.

<Defect area>
Defect regions are mixed in the first sealing layer.
The "defect region" referred to in the present invention means a foreign substance mixed in the first sealing layer by the gas phase method when forming the first sealing layer, and a foreign substance formed by the gas phase method by the foreign substance. The part where the membrane has grown abnormally.
Specifically, as shown in FIG. 1, the region including the foreign matter 4 and the abnormally grown portion 5 around the foreign matter 4 is referred to as a defect region 6. Further, a gap 7 is formed between the defect region 6 and the first sealing layer 2. The interval P of the gap 7 is preferably 15 nm or less, preferably 10 nm or less, when the cross section is observed at a 200 k magnification (acceleration voltage 200 kV) using an electron microscope (for example, JEM-2010F manufactured by JEOL). Is more preferable.
The interval P of the gap 7 was measured as follows.
_{First, a horizontal line A 1 at} a position of 1/3 and a horizontal line A _{2 at} a position of 2/3 are drawn from the lower side of the thickness of the first sealing layer 2. Next, in the first sealing layer 2, a _{tangent line B 1} connecting the intersecting points _{of the horizontal line A 1} at the 1/3 position and the horizontal line A ₂ at the 2/3 position is drawn. Similarly, in the abnormally grown portion 5, a _{tangent line B 2} connecting the intersecting points _{of the horizontal line A 1} at the 1/3 position and the horizontal line A ₂ at the 2/3 position is drawn. _{Then, the distance between the tangent line B 1} on the first sealing layer 2 side and the midpoint of the _{tangent line B 2} on the abnormally grown portion 5 side is measured.
In FIG. 1, reference numeral 1 indicates an electronic device, and reference numeral 3 indicates a second sealing layer.

The gap is provided with a polysilazane region filled with polysilazane.
The polysilazane region is formed by applying the ink composition of the present invention containing polysilazane, a high-drying solvent A, and a low-drying solvent B on the first sealing layer (second sealing layer forming step). , The ink composition is applied to the gap to form the gap. Therefore, by drying the coating film to which the ink composition is applied, the solvent contained in the coating film (solvent containing high-drying solvent A, low-drying solvent B, etc.) is removed, and polysilazane is contained. A polysilazane region will be formed in the gap. Since the gap between the first sealing layer and the defective region is sealed by such a polysilazane region, the sealing performance is improved.

<Second sealing layer>
The second sealing layer is a layer provided adjacent to the first sealing layer and containing polysilazane. The second sealing layer is formed by applying the ink composition on the first sealing layer.
Therefore, the second sealing layer is a solvent contained in the coating film (high-drying solvent A and low-drying solvent) by drying the coating film coated with the ink composition, similarly to the polysilazane region. The solvent (solvent containing B and the like) is removed to form a layer containing polysilazane.

<Third sealing layer>
The third sealing layer is a layer provided adjacent to the second sealing layer and formed by the vapor phase method described above. Specifically, it contains silicon nitride (SiN), silicon oxide (silicon monoxide, silicon dioxide, etc.) or silicon oxynitride as in the first sealing layer.

[Electronic device]
In the electronic device sealing layer forming method 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, a touch panel, an electronic paper, and a solar cell. (PV) and the like can be mentioned. From the viewpoint that the effects of the present invention can be obtained more efficiently, an organic EL element or a solar cell is preferable, and an organic EL element is particularly preferable.

<Organic EL element>
The organic EL element adopted as the electronic device according to the present invention may be a bottom emission type, that is, one in which light is extracted from the transparent substrate side.
Specifically, the bottom emission type is configured by laminating a transparent electrode serving as a cathode, a light emitting functional layer, and a counter electrode serving as an anode on a transparent base material in this order.
Further, the organic EL element according to the present invention may be a top emission type, that is, one in which light is taken out from the transparent electrode side which is the cathode opposite to the base material.
Specifically, the top emission type has a configuration in which a counter electrode serving as an anode is provided on the base material side, and a light emitting functional layer and a transparent electrode serving as a cathode are laminated in this order on the surface thereof.

A typical example of the configuration of the organic EL element is shown below.
(I) Anophode / hole injection transport layer / light emitting layer / electron injection transport layer / cathode (ii) anode / hole injection transport layer / light emitting layer / hole blocking layer / electron injection transport layer / cathode (iii) anode / Hole injection transport layer / electron blocking layer / light emitting layer / hole blocking layer / electron injection transport layer / cathode (iv) anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / Cathode (v) anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode (vi) anode / hole injection layer / hole transport layer / electron blocking Layer / light emitting layer / hole blocking layer / electron transporting layer / electron injection layer / cathode Further, the organic EL element may have a non-luminescent intermediate layer. The intermediate layer may be a charge generation layer or may have a multi-photon unit configuration.
Regarding the outline of the organic EL element applicable to the present invention, for example, Japanese Patent Application Laid-Open No. 2013-157634, Japanese Patent Application Laid-Open No. 2013-168552, Japanese Patent Application Laid-Open No. 2013-177361, Japanese Patent Application Laid-Open No. 2013-187211, JP-A-2013 2013-191644, 2013-191804, 2013-225678, 2013-235994, 2013-243234, 2013-243236, 2013-2013 242366, 2013-243371, 2013-245179, 2014-003249, 2014-003299, 2014-013910, 2014-017493 Examples thereof include the configurations described in Japanese Patent Application Laid-Open No. 2014-017494.

<Base material>
Specifically, as a base material (hereinafter, also referred to as a support substrate, a base, a substrate, a support, etc.) that can be used for the organic EL element, it is preferable to apply a glass or a resin film, and flexibility is required. If so, it is preferably a resin film.
Further, it may be transparent or opaque. In the case of the so-called bottom emission type in which light is extracted from the base material side, the base material is preferably transparent.

Preferred resins include polyester resin, methacrylic resin, methacrylic acid-maleic acid copolymer, polystyrene resin, transparent fluororesin, polyimide, fluorinated polyimide resin, polyamide resin, polyamideimide resin, polyetherimide resin, and cellulose acylate resin. , Polyurethane resin, polyether ether ketone resin, polycarbonate resin, alicyclic polyolefin resin, polyarylate resin, polyether sulfone resin, polysulfone resin, cycloolefin copolymer, fluorene ring-modified polycarbonate resin, alicyclic modified polycarbonate resin, fluorene ring modified Examples thereof include a base material containing a thermoplastic resin such as a polyester resin and an acryloyl compound. The resin can be used alone or in combination of two or more.

The base material 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.
The base material meets the requirements for electronic component applications and laminated films for displays. That is, when the sealing film of the present invention is used for these applications, the base material may be exposed to a step of 150 ° C. or higher. In this case, if the coefficient of linear expansion of the base material exceeds 100 ppm / K, the substrate dimensions will not be stable when the substrate is passed through the process at the above temperature, and the blocking performance will deteriorate due to thermal expansion and contraction. Or, the problem of not being able to withstand the thermal process is likely to occur. If it is less than 15 ppm / K, the film may break like glass and the flexibility may deteriorate.

The Tg and the coefficient of linear expansion of the base material can be adjusted with an additive or the like.
More preferable specific examples of the thermoplastic resin that can be used as a base material include, for example, polyethylene terephthalate (PET: 70 ° C.), polyethylene naphthalate (PEN: 120 ° C.), polycarbonate (PC: 140 ° C.), and alicyclic type. Polyethylene (for example, manufactured by Nippon Zeon Co., Ltd., Zeonoa (registered trademark) 1600: 160 ° C.), polyarylate (PAr: 210 ° C.), polyethersulfone (PES: 220 ° C.), polysulfone (PSF: 190 ° C.), cycloolefin copolymer (COC: Compound described in JP-A-2001-150584: 162 ° C.), Polyethylene (for example, manufactured by Mitsubishi Gas Chemicals Co., Ltd., Neoprim (registered trademark): 260 ° C.), Fluorene ring-modified polycarbonate (BCF-PC: JP-A.) Compound described in JP-A-2000-227603: 225 ° C.), alicyclic-modified polycarbonate (IP-PC: compound described in JP-A-2000-227603: 205 ° C.), acryloyl compound (Japanese Patent Laid-Open No. 2002-80616). The compound described: 300 ° C. or higher) and the like (the temperature in parentheses indicates Tg).

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

Further, the base material listed above may be an unstretched film or a stretched film. The base material can be produced by a conventionally known general method. As for the method for producing these base materials, the matters described in paragraphs "0051" to "0055" of International Publication No. 2013/002026 can be appropriately adopted.

The surface of the base material may be subjected to various known treatments for improving adhesion, such as corona discharge treatment, flame treatment, oxidation treatment, plasma treatment, etc., and the above treatments may be combined as necessary. May be. Further, the base material may be subjected to an easy-adhesion treatment.

The base material may have a single layer or a laminated structure of two or more layers. When the base material has a laminated structure of two or more layers, each base material may be of the same type or of a different type.

The thickness of the base material according to the present invention (in the case of a laminated structure of two or more layers, the total thickness thereof) is preferably 10 to 200 μm, more preferably 20 to 150 μm.

Further, in the case of a film base material, it is preferable that the film base material has a gas barrier layer.

The gas barrier layer for the film base material may have a film of an inorganic substance, an organic substance, or a hybrid film of both of them formed on the surface of the film base material, and is measured by a method according to JIS K 7129-1992. and water vapor transmission rate is preferably (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) is barrier film follows 0.01g / m ² · 24h, more, JIS K 7126- oxygen permeability was measured in compliance with the method 1987 ^{is, 1 × 10 -3 mL / m} 2 · 24h · atm or less, the water vapor permeability ^{is, 1 × 10 -3 g / m} 2 · 24h or less high gas barrier It is preferably a sex film.

The material for forming the gas barrier layer may be any material having a function of suppressing infiltration of substances such as moisture and oxygen that cause deterioration of the element, and for example, silicon monoxide, silicon dioxide, silicon nitride, silicon nitride, and the like. Silicon carbide, silicon acid acid carbide and the like can be used.

The gas barrier layer is not particularly limited, but in the case of an inorganic gas barrier layer such as silicon monoxide, silicon dioxide, silicon nitride, silicon oxynitride, silicon carbide, silicon acid carbide, for example, the inorganic material is subjected to a sputtering method (for example). , Magneton cathode sputtering, flat plate magnetron sputtering, bipolar AC flat plate magnetron sputtering, bipolar AC rotary magnetron sputtering, etc.), vapor deposition method (for example, resistance heating vapor deposition, electron beam deposition, ion beam deposition, plasma assisted vapor deposition, etc.), thermal CVD Method, catalytic chemical vapor deposition method (Cat-CVD), capacitively coupled plasma CVD method (CCP-CVD), optical CVD method, plasma CVD method (PE-CVD), epitaxial growth method, atomic layer growth method, reactive sputtering method It is preferable to form a layer by a chemical vapor deposition method or the like.

Further, a method of forming an inorganic gas barrier layer by applying a coating liquid containing an inorganic precursor such as polysilazane or tetraethyl orthosilicate (TEOS) on the support and then performing a modification treatment by irradiation with vacuum ultraviolet light or the like. The inorganic gas barrier layer is also formed by metal plating on a resin base material, film metallization technology such as bonding a metal foil and a resin base material, and the like.

Further, the inorganic gas barrier layer may 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.

The organic layer is, for example, coated with an organic monomer or an organic oligomer on a resin substrate to form a layer, which is subsequently polymerized using, for example, an electron beam device, a UV light source, a discharge device, or other suitable device. And, if necessary, it can be formed by cross-linking. It can also be formed, for example, by depositing an organic monomer or an organic oligomer capable of flash evaporation and radiation cross-linking, and then forming a polymer from the organic monomer or the organic oligomer. Coating efficiency can be improved by cooling the resin substrate.

Examples of the method for applying the organic monomer or organic oligomer include roll coating (for example, gravure roll coating) and spray coating (for example, electrostatic spray coating). In addition, examples of the laminate of the inorganic layer and the organic layer include the laminate described in International Publication No. 2012/003198 and International Publication No. 2011/013341.

In the case of a laminate of an inorganic layer and an organic layer, the thickness of each layer may 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.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the following examples, the operation was performed at room temperature (25 ° C.) unless otherwise specified. Unless otherwise specified, "%" and "parts" mean "mass%" and "parts by mass", respectively.

<Preparation of Ink Composition 1>
A 20% by mass dibutyl ether (DBE) solution of perhydropolysilazane (PHPS) (manufactured by AZ Electronic Materials Co., Ltd.) was dried under reduced pressure to remove the solvent.
After removing the solvent, it was diluted with a high-drying solvent A and a low-drying solvent B so that the perhydropolysilazane concentration became 10% by mass. Specifically, in a nitrogen environment, the mole fraction of DBE as a highly dry solvent A in all solvents was 0.11, and the mole fraction of DEGDBE as a low dry solvent B in all solvents was 0.89. Ink composition 1 was obtained by adding each solvent and stirring sufficiently.
In the preparation of the ink composition 1, the weight average molecular weight (Mw) of polysilazane determined from GPC (Gel Permeation Chromatography) polystyrene conversion was 7,000. The molecular weight of polysilazane was adjusted during the synthesis of polysilazane.
_{The mole fraction, vapor pressure, P total,} etc. of each solvent in the obtained ink composition 1 are shown in the table below.

<Preparation of ink compositions 2-39>
In the preparation of the ink composition 1, the weight average molecular weight (Mw) of PHPS, the pHPS concentration (mass%), the types of the high dry layer solvent A and the low dry solvent B, and the mole fraction in each solvent are shown in the table below. Ink compositions 2-39 were prepared in the same manner except that the above was changed.

<Manufacturing of organic EL element 1-1>
(1) Preparation of substrate A non-alkali glass substrate was prepared as a substrate.
(2) Formation of First Electrode An Al film was formed on one surface of the glass substrate as the first electrode (metal layer) under the following conditions. The thickness of the formed first electrode was 150 nm. The thickness of the first electrode is a value measured by a contact type surface shape measuring instrument (DECTAK).
The Al film was formed by using a vacuum deposition apparatus to ^{reduce the pressure to a vacuum degree of 1 × 10 -4} Pa, and then using a tungsten resistance heating crucible.

(3) Formation of Organic EL Layer First, each of the vapor deposition crucibles in the vacuum vapor deposition apparatus was filled with the following materials constituting each layer of the organic functional layer in the optimum amount for manufacturing the device. As the crucible for vapor deposition, a crucible made of molybdenum or tungsten made of a resistance heating material was used.

(3-1) Formation of hole injection layer ^{After depressurizing to a vacuum degree of 1 × 10 -4} Pa, the crucible for vapor deposition containing the following compound A-1 is energized and heated, and the vapor deposition rate is 0.1 nm / sec. A hole injection layer having a thickness of 10 nm was formed by vapor deposition on the first electrode (metal layer side).

(3-2) Formation of hole transport layer Next, the crucible for vapor deposition containing the following compound M-2 is energized and heated, and the hole is vapor-deposited on the hole injection layer at a vapor deposition rate of 0.1 nm / sec to make the thickness. A hole transport layer having a diameter of 30 nm was formed.

(3-3) Formation of Light Emitting Layer Next, the following compound BD-1 and the following compound H-1 are co-deposited at a vapor deposition rate of 0.1 nm / sec so that the compound BD-1 has a concentration of 7% by mass. , A light emitting layer (fluorescent light emitting layer) exhibiting blue light emission having a thickness of 15 nm was formed.
Next, the vapor deposition rate of the following compound GD-1, the following compound RD-1 and the following compound H-2 was set to 0% by mass so that the compound GD-1 had a concentration of 20% by mass and the RD-1 had a concentration of 0.5% by mass. Co-deposited at 1 nm / sec, a yellow light emitting layer (phosphorescent light emitting layer) having a thickness of 15 nm was formed.

(3-4) Formation of electron transport layer After that, a heating boat containing the following compound T-1 as an electron transport material is energized, and an _{electron transport layer made of Alq 3} (tris (8-quinolinol)) is placed on the light emitting layer. Formed in. At this time, the vapor deposition rate was set in the range of 0.1 to 0.2 nm / sec, and the thickness was set to 30 nm.

(3-5) Formation of Electron Injection Layer (Metal Affinity Layer) Next, a heating boat containing the following compound I-1 as an electron injection material is energized and heated, and the electron injection layer made of Liq is electron-transported. Formed on the layer. At this time, the vapor deposition rate was set in the range of 0.01 to 0.02 nm / sec, and the thickness was set to 2 nm. The electron injection layer functions as a metal affinity layer.
From the above, an organic EL layer that emits white light was formed.

(4) Formation of Second Electrode Further, a Mg / Ag mixture (Mg: Ag = 1: 9 (vol ratio)) was vapor-deposited to a thickness of 10 nm to form a second electrode and a take-out electrode thereof.

(5) Formation of capping layer After that, it is transferred into the original vacuum chamber, and α-NPD (4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl) is placed on the second electrode. Was vapor-deposited to a thickness of 40 nm within a vapor deposition rate of 0.1 to 0.2 nm / sec to form a capping layer for the purpose of improving light extraction.

(6) Formation of First Sealing Layer Next, as the first sealing layer covering the light emitting portion of the organic EL element produced above, silicon nitride (SiN, Vickers hardness HV900) having a thickness of 500 nm was used by a plasma CVD method. Formed.

(7) Formation of Second Sealing Layer Next, in a nitrogen environment, the cartridge-integrated head of the inkjet device was filled with the ink composition 1 prepared above. Then, the ink composition 1 is applied to the organic EL element formed up to the first sealing layer by an inkjet method in a nitrogen environment, and then the element is moved to a hot plate and dried at 100 ° C. for 5 minutes. A second sealing layer having a thickness of 300 nm was formed.

(8) Formation of Third Sealing Layer Next, silicon nitride (SiN, Vickers hardness HV900) having a thickness of 500 nm was formed as a third sealing layer on the second sealing layer by a plasma CVD method, and the first -The organic EL element 1-1 for evaluation in which the third sealing layer was formed was obtained.

<Manufacturing of organic EL elements 1-2 to 1-39>
In the production of the organic EL element 1-1, the same applies except that the ink composition 1 in the formation of the second sealing layer is changed as shown in the table below, and the organic EL elements 1-2 to evaluation are carried out in the same manner. 1-39 was prepared.

[Seal performance evaluation]
Each of the organic EL elements 1-2 to 1-39 for evaluation was left in a constant temperature and humidity chamber under high temperature and high humidity (temperature 85 ° C., relative humidity 85%) to perform an accelerated deterioration test. Each organic EL element was taken out from a constant temperature and humidity chamber at regular intervals to emit light at room temperature, and the presence or absence of dark spots (DS) during accelerated deterioration at 85 ° C. and 85% was confirmed. The time required for the dark spot area ratio in the light emitting region to reach 0.5% was defined as the life, and the life was evaluated. The longer the life, the higher the sealing performance. Ranks 3 to 5 of the following evaluation criteria were passed.
(Evaluation criteria)
Rank 1: Lifespan less than 50 hours Rank 2: Lifespan 50 hours or more and less than 100 hours Rank 3: Lifespan 100 hours or more and less than 300 hours Rank 4: Lifespan 300 hours or more and less than 500 hours Rank 5: Lifespan 500 hours or more

<Manufacturing of organic EL elements 2-1 to 2-39>
In the production of the organic EL element 1-1, instead of the non-alkali glass substrate, a 15-micron polyimide film was changed, and the thicknesses of the first sealing layer and the third sealing layer were changed to 1000 nm. An organic EL element 2-1 for evaluation was produced in the same manner except for the above.
Further, in the production of the organic EL element 2-1 in the same manner, the organic EL element 2-2 for evaluation is carried out in the same manner except that the ink composition 1 in the formation of the second sealing layer is changed as shown in the table below. ~ 2-39 was prepared.

[Bending resistance evaluation]
Each organic EL element 2-1 to 2-39 for evaluation is wrapped around a metal roller having a diameter of 10 mm and left in a constant temperature and humidity chamber under high temperature and high humidity (temperature 60 ° C., relative humidity 90%). Then, an accelerated deterioration test was conducted. At this time, the polyimide film is wound so as to be in contact with the metal roller. After 1500 hours, each organic EL element was taken out from the constant temperature and humidity chamber, and the state of light emission (dark spot area ratio) was confirmed by microscopic confirmation at room temperature. Ranks 3 to 5 of the following evaluation criteria were passed.
(Evaluation criteria)
Rank 1: Peeling of sealing layer or non-emission Rank 2: Dark spot area ratio is 1% or more Rank 3: Dark spot area ratio is 0.5% or more and less than 1% Rank 4: Dark spot area ratio is 0.1% More than 0.5% Rank 5: Dark spot area ratio is less than 0.1%

As shown in the above results, the organic EL device on which the sealing layer using the ink composition of the present invention is formed has higher sealing performance than the organic EL device of the comparative example, and at the time of bending. It can be seen that the adhesion between the sealing layer and the electronic device is good, and the light emitting performance is excellent.

Further, regarding the organic EL element on which the sealing layer using the ink composition of the present invention is formed, the foreign matter portion is identified by SEM observation (Hitachi High-Tech S4800) on the surface, and the foreign matter portion is identified by the FIB apparatus (JEOL JIB-4000PLUS). ) To prepare a flaky sample of the cross section. When the prepared cross section was observed with a TEM (JEM-2010F manufactured by JEOL, acceleration voltage 200 kV) at a magnification of 200 k, the gap between the defect region in the first sealing layer and the first sealing layer was found. The polysilazane region was confirmed. Therefore, it is recognized that the polysilazane region and the second sealing layer can provide an organic EL device having excellent sealing performance and bending resistance. The gaps were all 15 nm or less.
On the other hand, in the organic EL device of the comparative example, a void region was confirmed instead of the polysilazane region.

INDUSTRIAL APPLICABILITY The present invention is 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 are excellent in sealing performance and bending resistance and can suppress deterioration of an electronic device. can do.

1 Electronic device 2 1st sealing layer 3 2nd sealing layer 4 Foreign matter 5 Abnormally grown part 6 Defect area 7 Gap (polysilazane area)

Claims (8)

1. An ink composition for forming an electronic device encapsulating layer.
   Contains polysilazane,
   The ink composition contains at least one kind of a high drying solvent A having a vapor pressure of 8.0 × 10 ² Pa or more and a low drying solvent B having a ^{vapor pressure of 4.0 × 10 2 Pa or less at 20 ° C.} Contains more
   The mole fraction of the highly dry solvent A with respect to the total amount of the solvent is m _a1 , m _a2 , ..., And the mole fraction of the low dry solvent B is m _b1 , m _b2 , .... When the vapor pressures are P _a1 , P _a2 , ... And the vapor pressures of the low-drying solvent B are P _b1 , P _{b2 , ..., P total} represented by the following formula (i) is 0.5 ×. An ink composition for forming an electronic device encapsulating layer in the range of 10 ² to 3.6 × 10 ^{2 Pa.}
   (Equation i) P _total = P _a1 × _ma1 ＋ P _a2 × _ma2 ＋…, P _b1 × m _b1 ＋ P _b2 × m _b2 ＋…
2. The ink composition for forming an electronic device encapsulating layer according to claim 1, wherein the highly dry solvent A is dibutyl ether.
3. The ink composition for forming an electronic device encapsulating layer according to claim 1 or 2, wherein the low-drying solvent B is decalin.
4. A method of forming a sealing layer using the ink composition for forming an electronic device sealing layer according to any one of claims 1 to 3.
   The process of forming the first sealing layer on the electronic device by the vapor phase method,
   A method for forming an electronic device encapsulation layer, comprising a step of forming a second encapsulation layer by applying an ink composition for forming the electronic device encapsulation layer on the first encapsulation layer.
5. The electronic device encapsulation layer forming method according to claim 4, further comprising a step of forming a third encapsulation layer on the second encapsulation layer by a vapor phase method.
6. The electronic device encapsulation layer forming method according to claim 4 or 5, wherein the step of forming the second encapsulation layer is an inkjet method.
7. An electronic device sealing layer that seals an electronic device.
   A first sealing layer containing silicon nitride, silicon oxide or silicon oxynitride,
   Defect areas mixed in the first sealing layer and
   A second sealing layer provided adjacent to the first sealing layer and containing polysilazane,
   An electronic device sealing layer having a polysilazane region provided in a gap between the defect region and the first sealing layer and filled with polysilazane.
8. The electronic device encapsulation layer according to claim 7, wherein the gap between the gaps is 15 nm or less when the cross section is observed using an electron microscope.

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