TWI869951B - Composition for sealing electronic device, electronic device sealing film, and method for forming electronic device sealing film - Google Patents

Abstract

[Topic] The subject of the present invention is to provide an electronic device sealing composition that can obtain a sealing film with a good appearance after a reliability test in a bent state, excellent luminous efficiency after a bending reliability test, and low relative dielectric constant. Also, an electronic device sealing film using the electronic device sealing composition and a method for forming the same are provided. [Solution] The electronic component packaging composition of the present invention is an electronic component packaging composition containing a photopolymerizable monomer and a photopolymerization initiator, and is characterized in that the photopolymerizable monomer contains (meth)acrylate; when cured by irradiation with ultraviolet light of a wavelength of 395nm in a nitrogen environment at a power of 1.5Jcm ^-2 , the formed electronic device sealing film has a refractive index of 1.45 to 1.56 at a wavelength of 380nm, and an extinction coefficient of 50× ^10-5 to 200× ^10-5 at a wavelength of 380nm.

Description

Composition for sealing electronic device, electronic device sealing film, and method for forming electronic device sealing film

The present invention relates to an electronic device sealing composition, an electronic device sealing film and a method for forming an electronic device sealing film, and in particular to an electronic device sealing composition that can obtain a sealing film having a good appearance after a reliability test in a bent state, excellent luminous efficiency after a bending reliability test, and a low relative dielectric constant.

In electronic devices, especially organic electroluminescent devices (hereinafter also referred to as "organic EL devices" or "organic EL elements"), it has been proposed to cover the surface of the organic EL element with a sealing layer in order to prevent the organic materials or electrodes used therein from being deteriorated due to moisture.

As a technology for sealing an organic EL element, for example, the technology described in Patent Document 1 discloses an organic light-emitting element sealing composition containing a photopolymerizable (photocurable) monomer and an initiator, wherein the photopolymerizable monomer does not contain a silicon-based photopolymerizable monomer but contains a monomer containing a specific aromatic group and a monomer containing a non-aromatic group. By this technology, an organic light-emitting element sealing composition having a high refractive index and a high curing rate, excellent diffusibility, and a low plasma etching rate after curing can be provided.

However, in the technology described in the above-mentioned patent document 1, creases are produced after the reliability test in the bent state of the organic light-emitting element, which has a problem in appearance. In addition, after the organic light-emitting element is bent, there is a problem of reduced light-emitting efficiency. Even when an electric field is applied to an electronic device, it is difficult to achieve good polarization, and a lower relative dielectric constant is also desired. [Prior technical document] [Patent document]

[Patent Document 1] Japanese Patent Application Publication No. 2020-198304

[The problem that the invention wants to solve]

The present invention is developed in view of the above-mentioned problems and conditions, and the problem to be solved is to provide an electronic device sealing composition that can obtain a sealing film with a good appearance after a reliability test in a bent state, excellent luminous efficiency after a bending reliability test, and low relative dielectric constant. In addition, an electronic device sealing film using the electronic device sealing composition and a method for forming the same are provided. [Means for solving the problem]

The inventors of the present invention have studied the causes of the above problems in order to solve the above problems. They have found that by containing (meth)acrylate as a photopolymerizable monomer and setting the refractive index and extinction coefficient of the sealing film cured by irradiation under specific environmental conditions to a specific range, a sealing film with excellent appearance and luminous efficiency after a reliability test in a bent state and low relative dielectric constant can be obtained, and the present invention has been completed. That is, the above problems described in the present invention are solved by the following means.

1. An electronic device sealing composition comprising a photopolymerizable monomer and a photopolymerization initiator, wherein the photopolymerizable monomer comprises (meth)acrylate; when the composition is cured by irradiating ultraviolet light having a wavelength of 395 nm at 1.5 Jcm ^-2 in a nitrogen environment, the refractive index of the formed electronic device sealing film at a wavelength of 380 nm is in the range of 1.45 to 1.56, and the extinction coefficient of the electronic device sealing film at a wavelength of 380 nm is in the range of 50×10 ^-5 to 200×10 ^-5 .

2. The electronic device sealing composition as described in item 1, wherein the refractive index is in the range of 1.50 to 1.53.

3. The electronic device sealing composition as described in item 1, wherein the extinction coefficient is in the range of 125×10 ^-5 to 200×10 ^-5 .

4. The electronic device sealing composition as described in item 1, wherein the refractive index n and the extinction coefficient k satisfy the following relationship: .

5. The electronic device sealing composition as described in item 1, wherein the average double bond number of the photopolymerizable monomer contained in the electronic device sealing composition is 5 or less.

6. The electronic device sealing composition as described in item 1, wherein the energy levels of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of the photopolymerizable monomer contained in the electronic device sealing composition satisfy the following relationship: .

7. An electronic device sealing film for sealing an electronic device by curing an electronic component packaging composition containing a photopolymerizable monomer and a photopolymerization initiator, wherein the photopolymerizable monomer contains (meth)acrylate; the refractive index of the electronic device sealing film at a wavelength of 380 nm is in the range of 1.45 to 1.56, and the extinction coefficient of the electronic device sealing film at a wavelength of 380 nm is in the range of 50×10 ^-5 to 200×10 ^-5 .

8. An electronic device sealing film is an electronic device sealing film for sealing an electronic device, characterized by having: A first sealing layer containing: silicon nitride, silicon oxide or silicon oxynitride; and A second sealing layer using an electronic device sealing composition as described in any one of items 1 to 6.

9. The electronic device sealing film as described in item 8, wherein a third sealing layer is provided on the second sealing layer, and the third sealing layer contains silicon nitride, silicon oxide or silicon nitride oxide.

10. A method for forming an electronic device sealing film, which is a method for forming an electronic device sealing film using an electronic device sealing composition as described in any one of items 1 to 6, characterized by comprising: a process of forming a first sealing layer on an electronic device by a vapor phase method; and a process of forming a second sealing layer by applying the electronic device sealing composition on the first sealing layer.

11. The method for forming a sealing film for an electronic device as recited in item 10, comprising: forming a third sealing layer on the second sealing layer by a vapor phase method.

12. The method for forming a sealing film for an electronic device as described in item 10, wherein the second sealing layer is formed by an inkjet method. [Effect of the invention]

By means of the above-mentioned means of the present invention, a sealing composition for electronic devices can be provided, which can obtain a sealing film with good appearance after a reliability test in a bent state, excellent luminous efficiency after a bending reliability test, and low relative dielectric constant. In addition, an electronic device sealing film using the electronic device sealing composition and a method for forming the same are provided. The presentation mechanism or action mechanism of the effect of the present invention is not yet clear, but it is inferred as follows.

(Appearance after reliability test in a bent state) Once a reliability test in a bent state is performed, a creep phenomenon will occur due to the long-term application of bending stress, and the hardened film will deform. Due to this deformation, the optical path length will change, resulting in a change in appearance after the reliability test. In the present invention, the refractive index of the sealing film and the extinction coefficient as a measure of light absorption are set in the aforementioned specific range, and the optical appearance change accompanying deformation in the bent state is difficult to occur by balancing the refraction and absorption of light. That is, by shortening the optical path length with a lower refractive index to reduce the optical path length change before and after the reliability test in the bent state, and then by absorbing light to reduce the amount of reflected light from the outside, the crease after the reliability test in the bent state can be suppressed to improve the appearance.

(Luminous efficiency after bending reliability test) By performing repeated bending reliability tests, there is a risk that the hardened film may be deformed or cracked. Once the hardened film is deformed or has tiny cracks, the emission mode of light from the light-emitting element may change. That is, once deformed, the light will be emitted in a lateral direction due to the change in optical path length and refraction of light, and once cracks occur, the light may not be emitted due to the difference in refractive index between the air and the crack. Therefore, in the present invention, it is speculated that by setting the refractive index of the sealing film to the above-mentioned specific range, the refraction of light can be suppressed, the difference in refractive index with the air layer in the tiny cracks can be suppressed, and the high luminous efficiency can be maintained after the bending state.

(Relative dielectric constant) What is even more surprising is that when the refractive index of the sealing film and the extinction coefficient, which is a measure of light absorption, fall within the aforementioned specific range, the relative dielectric constant actually becomes lower. Although the mechanism of action is not yet clear, it is believed that by setting it within a specific range, the energy gap becomes larger, making it difficult for electron migration to occur. Dielectric constant is caused by electron polarization. Electron polarization occurs due to the distribution of electrons caused by the disturbance of the electric field. By making it difficult for electron migration to occur, it is difficult to produce a larger electron distribution.

The electronic device encapsulation composition of the present invention is a composition for encapsulating electronic devices containing a photopolymerizable monomer and a photopolymerization initiator, wherein the photopolymerizable monomer contains (meth)acrylate; when cured by irradiating ultraviolet light with a wavelength of 395 nm to 1.5 Jcm ^-2 in a nitrogen environment, the refractive index of the formed electronic device sealing film at a wavelength of 380 nm is within the range of 1.45 to 1.56, and the extinction coefficient of the electronic device sealing film at a wavelength of 380 nm is within the range of 50×10 ^-5 to 200×10 ^-5 . This feature is a feature of the technology common to or corresponding to each of the following embodiments.

In an embodiment of the present invention, the refractive index is within the range of 1.50 to 1.53, and the extinction coefficient is within the range of 125×10 ^-5 to 200×10 ^-5 , which is preferable in terms of appearance and luminous efficiency after reliability testing in a bent state.

The refractive index n and the extinction coefficient k satisfy the relationship of k/n≧100×10 ^-5 , which is preferable from the viewpoint of the appearance after the reliability test in the bent state and the luminous efficiency after the bending reliability test.

The average double bond number of the photopolymerizable monomer contained in the electronic device sealing composition is preferably 5 or less from the viewpoint of the appearance after the reliability test in the folded state and the luminescence efficiency after the folded reliability test.

Furthermore, the energy levels of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of the photopolymerizable monomer contained in the electronic device sealing composition satisfy: This is better from the perspective of appearance after the reliability test in the bent state, luminous efficiency after the bending reliability test, and relative dielectric constant.

An electronic device sealing film according to one aspect of the present invention is an electronic device sealing film for sealing an electronic device by curing an electronic device sealing composition containing a photopolymerizable monomer and a photopolymerization initiator, wherein the photopolymerizable monomer contains (meth)acrylate, the refractive index of the electronic device sealing film at a wavelength of 380 nm is in the range of 1.45 to 1.56, and the extinction coefficient of the electronic device sealing film at a wavelength of 380 nm is in the range of 50×10 ^-5 to 200×10 ^-5 . Thus, the electronic device sealing film can have a good appearance after a reliability test in a bent state, excellent luminous efficiency after a bending reliability test, and a low relative dielectric constant.

Another aspect of the electronic device sealing film of the present invention is an electronic device sealing film for sealing an electronic device, and is characterized by having: a first sealing layer containing: silicon nitride, silicon oxide or silicon oxynitride; and a second sealing layer using the aforementioned electronic device sealing composition. Thus, an electronic device sealing film having a good appearance after a reliability test in a bent state, excellent luminous efficiency after a bending reliability test, and low relative dielectric constant can be obtained.

Furthermore, it is preferred that a third sealing layer is provided on the second sealing layer and that the third sealing layer contains silicon nitride, silicon oxide or silicon oxynitride, from the viewpoint of excellent sealing performance.

The method for forming an electronic device sealing film of the present invention is a method for forming a sealing film using the aforementioned electronic device sealing composition, and is characterized by comprising: a process of forming a first sealing layer on an electronic device by a vapor phase method; and a process of forming a second sealing layer by applying the aforementioned electronic device sealing composition on the aforementioned first sealing layer. Thereby, an electronic device sealing film having a good appearance after a reliability test in a bent state and excellent luminous efficiency after a bending reliability test can be formed.

The process of forming the third sealing layer on the second sealing layer by a vapor phase method is preferred from the viewpoint of excellent sealing performance. In addition, the process of forming the second sealing layer is preferably performed by an inkjet method from the viewpoint of being able to form the layer with high precision.

The present invention and its constituent elements and the forms and aspects required for implementing the present invention are described below. In addition, in the present case, the numerical values recorded before and after "～" are used as the meaning of being inclusive of the lower limit and the upper limit.

[Overview of the electronic device sealing composition of the present invention] The electronic device sealing composition of the present invention (hereinafter also referred to as the "sealing composition") is an electronic component sealing composition containing a photopolymerizable monomer and a photopolymerization initiator. The photopolymerizable monomer contains (meth)acrylate. When cured by irradiating ultraviolet rays with a wavelength of 395nm at 1.5Jcm ^-2 in a nitrogen environment, the formed electronic device sealing film (hereinafter also referred to as the "sealing film") has a refractive index of 1.45 to 1.56 at a wavelength of 380nm, and the extinction coefficient of the electronic device sealing film at a wavelength of 380nm is in the range of 50× ^10-5 to 200× ^10-5 , which is its characteristic.

<Refractive Index> When the sealing composition of the present invention is cured by irradiating ultraviolet light at a wavelength of 395 nm at 1.5 Jcm ^-2 in a nitrogen environment, the refractive index of the sealing film formed therefrom at a wavelength of 380 nm is in the range of 1.45 to 1.56, preferably in the range of 1.50 to 1.53.

The refractive index is obtained by using a spectroscopic ellipsometer (UVSEL/FUV-FGMS, manufactured by HORIBA JYOBIN-YVON Co., Ltd.). Specifically, the refractive index at 250 nm to 800 nm is measured, and the refractive index n at 380 nm is obtained.

As means for making the aforementioned refractive index fall within the range of 1.45 to 1.56, for example, a structure with fewer impurity atoms in the monomer structure, an alicyclic hydrocarbon structure, and a lock hydrocarbon structure can be cited, but it is not limited to these. As the structure of the alicyclic hydrocarbon, specifically, alicyclic (meth)acrylates such as isoborneol (meth)acrylate, dicyclopentyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and cyclohexyl (meth)acrylate, 1,3-adamandiol di(meth)acrylate, 1,3-adamantanedimethanol di(meth)acrylate, 2-methyl-2-adamantanyl (meth)acrylate, 2-ethyl-2-adamantanyl (meth)acrylate, 3-hydroxy-1-adamantanyl (meth)acrylate, 1-adamantanyl (meth)acrylate, and tricyclodecanedimethanol (meth)acrylate can be cited, but the present invention is not limited thereto. Examples of the chain hydrocarbon structure include 1,6-hexanediol di(meth)acrylate, 1,7-heptanediol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 1,11-undecanediol (meth)acrylate, 1,12-dodecanediol di(meth)acrylate, 2-ethylhexyl (meth)acrylate, isostearyl (meth)acrylate, lauryl (meth)acrylate, hexyl (meth)acrylate, and isodecyl (meth)acrylate, but the present invention is not limited thereto. Another example is the addition of particles having a desired refractive index within a range that does not impair the ejection properties of the inkjet. In addition, the refractive index of the photopolymerizable monomer constituting the sealing composition can be obtained by using an Abbe refractometer, and the refractive index (nd25) of the D line at 25°C is preferably 1.43 to 1.50.

<Extinction coefficient> When the sealing composition of the present invention is cured by irradiating ultraviolet light at a wavelength of 395 nm at 1.5 Jcm ^-2 in a nitrogen environment, the extinction coefficient of the sealing film formed therefrom at a wavelength of 380 nm is in the range of 50×10 ^-5 to 200×10 ^-5 , preferably in the range of 125×10 ^-5 to 200×10 ^-5 .

The extinction coefficient is obtained in the same manner as the refractive index using a spectroscopic ellipsometer (UVSEL/FUV-FGMS, manufactured by HORIBA JYOBIN-YVON CO., LTD.). Specifically, the extinction coefficient at 250 nm to 800 nm is measured, and the extinction coefficient k at 380 nm is obtained.

As means for making the extinction coefficient fall within the range of 50×10 ^-5 to 200×10 ^-5 , for example, the use of monomers with fewer impurity atoms, fewer aromatic hydrocarbons, and fewer multiple bonds can be cited. Another example is the addition of pigments within a range that does not impair the luminescent properties of the organic EL.

Furthermore, it is preferable that the refractive index n and the extinction coefficient k satisfy the following relationship from the viewpoints of the appearance after the reliability test in the bent state and the luminous efficiency after the bending reliability test.

[Composition of electronic device sealing composition] The electronic device sealing composition of the present invention contains a photopolymerizable monomer and a photopolymerization initiator. The photopolymerizable monomer contains (meth)acrylate.

In this specification, "(meth)acrylate" means at least one of acrylate and methacrylate. In addition, the "electronic device" in the present invention refers to a component that uses the kinetic energy, potential energy, etc. of electrons to generate, amplify, convert, or control electrical signals. For example, active components such as light-emitting diode components, organic electroluminescent components, photoelectric conversion components, and transistors. In addition, in the present invention, passive components such as resistors and capacitors that perform passive work such as "impedance" and "storage" for actions from others are also included in electronic devices. Therefore, the sealing composition of the present invention is used to form the aforementioned sealing film required to seal the electronic device.

<Photopolymerizable monomer> The so-called "photopolymerizable monomer" means a photopolymerizable monomer (also called "photocurable monomer") that absorbs light by itself or a photopolymerization initiator and can undergo a polymerization (hardening) reaction by generating active ions or free radicals. As the aforementioned photopolymerizable monomer, a non-silicon monomer that does not contain silicon (Si) can also be used, for example, a monomer composed of only elements selected from C, H, O, N or S, but it is not limited thereto. The photopolymerizable monomer can be synthesized and used by a conventional synthesis method, or it can be purchased and used as a commercially available product. As the aforementioned photopolymerizable monomer, there can be cited the following photopolymerizable monomer (A) without an aromatic hydrocarbon group, or the photopolymerizable monomer (B) with an aromatic hydrocarbon group, etc. When used as a sealing film as described above, the aforementioned photopolymerizable monomer is appropriately selected so that the aforementioned refractive index and extinction coefficient satisfy the aforementioned range.

(Average number of double bonds) The average number of double bonds of the photopolymerizable monomer contained in the electronic device sealing composition of the present invention is 5 or less, which is preferable from the viewpoint of the appearance after the reliability test in the bent state and the luminous efficiency after the bending reliability test.

The above average double bond number is calculated as follows using the mass ratio w of each monomer, assuming that the number of double bonds contained in each monomer is d and the total mass of all monomers is 1. Average double bond number = d1×w1+d2×w2+… (The suffixes d and w represent the monomer numbers.)

(Energy levels of HOMO and LUMO) The average value of the energy level of the highest occupied molecular orbital (HOMO) and the average value of the energy level of the lowest unoccupied molecular orbital (LUMO) of the aforementioned photopolymerizable monomer contained in the sealing composition of the present invention satisfy the following relationship, which is preferable from the viewpoints of the appearance after the reliability test in the bent state, the luminescence efficiency after the bending reliability test, and the relative dielectric constant. Here, the average value of the energy level of the highest occupied molecular orbital (HOMO) and the average value of the energy level of the lowest unoccupied molecular orbital (LUMO) are calculated by the following formula. Average value of HOMO = HOMO1×w1+HOMO2×w2+… Average value of LUMO = LUMO1×w1+LUMO2×w2+… In the above formula, w represents the mass ratio of each monomer mentioned above. In addition, the suffixes of w, HOMO and LUMO represent the numbers of the monomers.

HOMO and LUMO can be calculated by using chemical structure information computer software. As calculation software, for example, the quantum chemical calculation program "Gaussian series" made by HULINKS can be cited. Based on the HOMO and LUMO values of each monomer obtained using the above software, the average value of the above HOMO and the average value of the above LUMO are calculated, and the energy gap (Gap) of the average values of these HOMO and LUMO is calculated. In the calculation, B3LYP is used as a functional. Gap (unit: eV) = average value of LUMO - average value of HOMO As a means to set the aforementioned Gap to 5.9eV≦LUMO-HOMO≦6.5eV, there are examples of using a structure with fewer impurity atoms in the structure of the monomer, a structure of alicyclic hydrocarbons, a structure of chain hydrocarbons, etc.

<Photopolymerizable monomer (A) without aromatic hydrocarbon group> The aforementioned photopolymerizable monomer (A) without aromatic hydrocarbon group (hereinafter also referred to as "photopolymerizable monomer (A)") does not contain aromatic hydrocarbon group, and as a photocurable functional group (photopolymerizable functional group), it is a monomer containing one or more of vinyl, acrylic and methacrylic groups up to 1 to 20, specifically, 1 to 6 monomers, for example, 1 to 3, 1 to 2, 1, or 2.

In the present invention, the weight average molecular weight of the photopolymerizable monomer (A) may be in the range of 100 to 500 g/mol, 130 to 400 g/mol, or 200 to 300 g/mol. By setting the weight average molecular weight of the monomer in the range, a more favorable effect can be achieved for the process.

The photopolymerizable monomer (A) may contain a monofunctional monomer, a polyfunctional monomer, or a mixture thereof having a photocurable functional group.

Specifically, the photopolymerizable monomer (A) may be a (meth)acrylate monomer, an unsaturated carboxylic acid ester having an alkyl group with 1 to 20 carbon atoms, a cycloalkyl group with 3 to 20 carbon atoms, a hydroxyl group, and an alkyl group with 1 to 20 carbon atoms; an unsaturated carboxylic acid ester having an aminoalkyl group with 1 to 20 carbon atoms; a vinyl ester of a saturated or unsaturated carboxylic acid with 1 to 20 carbon atoms; a vinyl cyanide compound; an unsaturated amide compound; a monofunctional or polyfunctional (meth)acrylate of a monohydric alcohol or polyhydric alcohol, etc. The aforementioned "polyol" is an alcohol having two or more hydroxyl groups, which may mean an alcohol having 2 to 20, preferably 2 to 10, and more preferably 2 to 6 hydroxyl groups.

In one example, among the photopolymerizable monomers (A), the (meth)acrylate monomer having no aromatic hydrocarbon group may be a mono(meth)acrylate, a di(meth)acrylate, a tri(meth)acrylate, a tetra(meth)acrylate, or the like having a substituted or unsubstituted C1-C20 (carbon number 1-20) alkyl group, a substituted or unsubstituted C1-C20 silyl group, a substituted or unsubstituted C3-C20 cycloalkyl group, a substituted or unsubstituted C1-C20 alkylene group, an amino group, an ethylene oxide group, or the like.

Specifically, the (meth)acrylate monomers without aromatic hydrocarbons may include: unsaturated carboxylates containing (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, cyclohexyl (meth)acrylate, etc.; unsaturated carboxyl aminoalkyl esters such as 2-aminoethyl (meth)acrylate and 2-dimethylaminoethyl (meth)acrylate; saturated or unsaturated carboxyl vinyl esters such as vinyl acetate; vinyl cyanide compounds such as (meth)acrylonitrile; and unsaturated amide compounds such as (meth)acrylamide. Ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, trihydroxymethylpropane tri(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, octanediol di(meth)acrylate, nonanediol di(meth)acrylate, decanediol di(meth)acrylate, undecanediol di(meth)acrylate, dodecanediol (meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol di(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, or a mixture thereof, but is not limited thereto.

In one example of the present invention, the photopolymerizable monomer (A) is a non-aromatic system without an aromatic group, and may also include: a mono(meth)acrylate having an alkyl group with a carbon number of 1 to 20, a mono(meth)acrylate having an amino group, a di(meth)acrylate having a substituted or unsubstituted alkylene group with a carbon number of 1 to 20, a di(meth)acrylate having an oxirane group, a tri(meth)acrylate having an oxirane group, a mono(meth)acrylate having a cyclic carbonized alkyl group, and at least one of di(meth)acrylates.

The mono(meth)acrylate having a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms may specifically be decyl(meth)acrylate, undecyl(meth)acrylate, lauryl(meth)acrylate, tridecyl(meth)acrylate, tetradecyl(meth)acrylate, pentadecyl(meth)acrylate, hexadecyl(meth)acrylate, heptadecyl(meth)acrylate, octadecyl(meth)acrylate, nonadecyl(meth)acrylate, eicosyl(meth)acrylate, or a mixture thereof, but is not limited thereto.

The mono(meth)acrylate having an amino group may be 2-aminoethyl(meth)acrylate, 2-dimethylaminoethyl(meth)acrylate, or a mixture thereof, but is not limited thereto.

The di(meth)acrylate having a substituted or unsubstituted alkylene group with 1 to 20 carbon atoms may be, for example, a di(meth)acrylate having an alkylene group with 1 to 20 carbon atoms, or a non-silicon di(meth)acrylate containing a substituted or unsubstituted long-chain alkylene group. The di(meth)acrylate having a substituted or unsubstituted alkylene group with 1 to 20 carbon atoms may be, for example, octanediol di(meth)acrylate, nonanediol di(meth)acrylate, decanediol di(meth)acrylate, undecanediol di(meth)acrylate, dodecanediol (meth)acrylate, or a mixture thereof, but is not limited thereto. In the case of containing the aforementioned (meth)acrylate having a substituted or unsubstituted alkylene group with 1 to 20 carbon atoms, the light curing rate of the sealing composition of the present invention will be further improved, and the viscosity can be reduced.

The di(meth)acrylate or tri(meth)acrylate having an ethylene oxide group may be, specifically, ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, trihydroxymethylpropane tri(meth)acrylate, or a mixture thereof, but is not limited thereto.

The mono(meth)acrylate and di(meth)acrylate having a cyclic carbonized alkyl group may be specifically isoborneol (meth)acrylate, tricyclodecanedimethanol di(meth)acrylate, dicyclopentyl (meth)acrylate, dicyclopentenylethoxy (meth)acrylate, or dicyclopentenyl (meth)acrylate, but is not limited thereto.

The photopolymerizable monomer (A) is preferably contained in an amount of 55 to 95% by mass, more preferably 60 to 90% by mass, relative to the total mass of the photopolymerizable monomers (photopolymerizable monomer (A) and photopolymerizable monomer (B)). By setting the amount within the above range, the viscosity of the sealing composition of the present invention will be suitable for forming a sealing film for electronic devices.

<Photopolymerizable monomer (B) having an aromatic hydrocarbon group> The aforementioned photopolymerizable monomer (B) having an aromatic hydrocarbon group (hereinafter also referred to as "photopolymerizable monomer (B)") contains two or more phenyl groups and heteroatoms having a structure represented by the following general formula (1), and the aforementioned photopolymerizable monomer (B) contains at least mono(meth)acrylate or di(meth)acrylate.

[In the above general formula (1), P represents a substituted or unsubstituted alkyl group containing two or more phenyl groups, or a substituted or unsubstituted alkyl group containing a heteroatom of two or more phenyl groups. ^Z1 and ^Z2 each independently have a structure represented by the following general formula (2). a and b are each an integer of 0 to 2, and a+b is an integer of 1 to 4.]

[In the above general formula (2), * is a linking part to the carbon of P. X represents a single bond, O or S. Y represents a substituted or unsubstituted linear alkylene group having 1 to 10 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms. ^R1 represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. c is an integer of 0 or 1.]

In the above general formula (1), P represents a alkyl group containing two or more substituted or unsubstituted phenyl groups, or a alkyl group containing a heteroatom containing two or more substituted or unsubstituted phenyl groups. The above alkyl group containing two or more substituted or unsubstituted phenyl groups, or a heteroatom-containing alkyl group containing two or more substituted or unsubstituted phenyl groups means that the two or more substituted or unsubstituted phenyl groups are not condensed but are linked via a single bond, an oxygen atom, a sulfur atom, a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, an alkylene group having 3 to 6 carbon atoms substituted or unsubstituted with a heteroatom, an ethenylene group, an ethynylene group, or a carbonyl group.

For example, the aforementioned alkyl group containing two or more phenyl groups or the heteroatom-containing alkyl group containing two or more phenyl groups may also include: substituted or unsubstituted biphenyl group, substituted or unsubstituted triphenylmethyl group, substituted or unsubstituted terphenyl group, substituted or unsubstituted extended biphenyl group, substituted or unsubstituted extended triphenyl group, substituted or unsubstituted extended tetraphenyl group, substituted or unsubstituted 2-phenyl-2-(phenylthio)ethyl group, substituted or unsubstituted 2,2-diphenylpropyl group, substituted or unsubstituted diphenylmethyl group, substituted or unsubstituted isopropylphenyl group, substituted or unsubstituted bisphenol F group, substituted or unsubstituted bisphenol A group, substituted or unsubstituted biphenyloxy group, substituted or unsubstituted terphenyloxy group, substituted or unsubstituted tetraphenyloxy group, substituted or unsubstituted pentphenyloxy group, and structural isomers thereof, but are not limited thereto.

The aforementioned monomer having two or more substituted or unsubstituted phenyl groups may be a mono(meth)acrylate, a di(meth)acrylate, or a mixture thereof, and examples thereof include: 4-(meth)acryloyloxy-2-hydroxybenzophenone, ethyl-3,3-diphenyl(meth)acrylate, benzoyloxyphenyl(meth)acrylate, bisphenol A di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, bisphenol F di(meth)acrylate, ethoxylated bisphenol F di(meth)acrylate, (Meth)acrylate, 4-isopropylphenylphenoxyethyl acrylate, ethoxylated bisphenylfluorene diacrylate, 2-phenylphenoxyethyl (meth)acrylate, 2,2'-phenylphenoxyethyl di(meth)acrylate, 2-phenylphenoxypropyl (meth)acrylate, 2,2'-phenylphenoxypropyl di(meth)acrylate, 2-phenylphenoxybutyl (meth)acrylate, 2,2'-phenylphenoxybutyl di(meth)acrylate, 2-(3-phenylphenyl)ethyl (meth)acrylate, 2-(4-benzylphenyl)ethyl (meth)acrylate, 2-phenyl-2-(phenylthio)ethyl (meth)acrylate, 2-(triphenylmethyloxy)ethyl (meth)acrylate, 4-(triphenylmethyloxy)butyl (meth)acrylate, 3-(biphenyl-2-yloxy)butyl (meth)acrylate, 2-(biphenyl-2-yloxy)butyl (meth)acrylate, 4-(biphenyl-2-yloxy)propyl (meth)acrylate, 3-(biphenyl-2-yloxy)butyl (meth)acrylate -2-yloxy)propyl (meth)acrylate, 2-(biphenyl-2-yloxy)propyl (meth)acrylate, 4-(biphenyl-2-yloxy)ethyl (meth)acrylate, 3-(biphenyl-2-yloxy)ethyl (meth)acrylate, 2-(4-benzylphenyl)ethyl (meth)acrylate, 4,4'-bis(acryloyloxymethyl)biphenyl, 2,2'-bis(2-acryloyloxyethoxy)biphenyl, structural isomers thereof or mixtures thereof, but are not limited thereto. In addition, the (meth)acrylate mentioned in the present invention is only an example and is not limited thereto. In fact, the present invention also includes all acrylates in a structural isomer relationship. For example, as an example of the present invention, even if only 2,2'-phenylphenoxyethyl di(meth)acrylate is mentioned, the present invention still includes 3,2'-phenylphenoxyethyl di(meth)acrylate, 3,3'-phenylphenoxyethyl di(meth)acrylate, etc., which are equivalent to all its structural isomers.

In one embodiment of the present invention, the monomer having two or more phenyl groups may be a mono(meth)acrylate represented by the following general formula (4).

In the above general formula (4), ^R2 is hydrogen or methyl, ^R3 is a substituted or unsubstituted linear alkylene group having 1 to 10 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, and ^R4 is a substituted or unsubstituted alkyl group containing two or more phenyl groups, or a heteroatom-containing alkyl group containing two or more phenyl groups.

For example, the aforementioned alkyl group containing two or more substituted or unsubstituted phenyl groups, or the heteroatom-containing alkyl group containing two or more substituted or unsubstituted phenyl groups means that the two or more substituted or unsubstituted phenyl groups are not condensed but are linked by a single bond, an oxygen atom, a sulfur atom, a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms, an alkylene group having 3 to 6 carbon atoms substituted or unsubstituted with a heteroatom, a vinylene group, an ethynylene group, or a carbonyl group. For example, the aforementioned alkyl group containing two or more substituted or unsubstituted phenyl groups, or the alkyl group containing a heteroatom containing two or more substituted or unsubstituted phenyl groups, may also include: substituted or unsubstituted biphenyl group, substituted or unsubstituted triphenylmethyl group, substituted or unsubstituted terphenyl group, substituted or unsubstituted extended biphenyl group, substituted or unsubstituted extended triphenyl group, substituted or unsubstituted extended tetraphenyl group, substituted or unsubstituted 2-phenyl-2-(phenylthio)ethyl group, substituted or unsubstituted 2,2-diphenylpropyl group, substituted or unsubstituted diphenylmethyl group, substituted or unsubstituted isopropylphenyl group, substituted or unsubstituted bisphenol F group, substituted or unsubstituted bisphenol A group, substituted or unsubstituted biphenyloxy group, substituted or unsubstituted terphenyloxy group, substituted or unsubstituted tetraphenyloxy group, substituted or unsubstituted pentphenyloxy group, etc., but are not limited thereto.

In one embodiment of the present invention, the monomer having two or more phenyl groups may be a di(meth)acrylate represented by the following general formula (5).

In the above general formula (5), ^R5 and ^R9 are independently hydrogen or methyl, ^R6 and ^R8 are independently substituted or unsubstituted linear alkylene groups having 1 to 10 carbon atoms, or substituted or unsubstituted alkoxy groups having 1 to 20 carbon atoms, and ^R7 is a substituted or unsubstituted alkyl group containing two or more phenyl groups, or a heteroatom-containing alkyl group containing two or more phenyl groups.

For example, the aforementioned alkyl group containing two or more substituted or unsubstituted phenyl groups, or the heteroatom-containing alkyl group containing two or more substituted or unsubstituted phenyl groups means that the two or more substituted or unsubstituted phenyl groups are not condensed, but are linked by a single bond, an oxygen atom, a sulfur atom, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, an alkylene group having 3 to 6 carbon atoms substituted or unsubstituted with a heteroatom, an ethenylene group, an ethynylene group, or a carbonyl group. For example, the aforementioned alkyl group may also include: substituted or unsubstituted biphenylene group, substituted or unsubstituted triphenylmethylene group, substituted or unsubstituted triphenylene group, substituted or unsubstituted tetraphenylene group, 2-phenyl-2-(phenylthio)ethylene group, 2,2-diphenylpropylene group, diphenylmethylene group, etc., but is not limited thereto.

In the above general formula (1), a and b are integers of 0 to 2 respectively, and a+b is an integer of 1 to 4. In one example, a+b is an integer of 1 or 2.

The weight average molecular weight of the aforementioned monomer having two or more substituted or unsubstituted phenyl groups is preferably in the range of 100 to 1000 g/mol, more preferably in the range of 130 to 700 g/mol, and particularly preferably in the range of 150 to 600 g/mol. By setting it within the aforementioned range, a sealing film with better permeability can be provided.

The aforementioned photopolymerizable monomer (B) having an aromatic hydrocarbon group is preferably contained in an amount of 5 to 45% by mass, more preferably 10 to 40% by mass, relative to the total mass of the aforementioned photopolymerizable monomers (photopolymerizable monomer (A) and photopolymerizable monomer (B)). By setting it within the aforementioned range, the viscosity thereof will be suitable for forming a sealing film.

In addition, specific examples of the photopolymerizable monomers (A) and (B) include the monomers listed in the examples described below in addition to the above-mentioned monomers. The preferred combination of the photopolymerizable monomers in the present invention is as described in the examples described below.

<Photopolymerization initiator> The photopolymerization initiator is not particularly limited as long as it is a common photopolymerization initiator capable of photocuring reaction. The photopolymerization initiator may include, for example, triazine, acetophenone, benzophenone, thioxanone, benzoin, phosphorus, oxime or a mixture thereof.

The triazine initiator may also be: 2,4,6-trichloro-s-triazine, 2-phenyl-4,6-bis(trichloromethyl)-s-triazine, 2-(3',4'-dimethoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4'-methoxynaphthyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(p-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(p-tolyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(Trichloromethyl)-6-phenylvinyl-s-triazine, 2-(1-naphthalenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methoxynaphthalen-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2,4-trichloromethyl(piperonyl)-6-triazine, 2,4-(trichloromethyl(4'-methoxyphenylvinyl)-6-triazine or a mixture thereof.

The acetophenone-based initiator may be 2,2'-diethoxyacetophenone, 2,2'-dibutoxyacetophenone, 2-hydroxy-2-methylpropiophenone, p-t-butyltrichloroacetophenone, p-t-butyldichloroacetophenone, 4-chloroacetophenone, 2,2'-dichloro-4-phenoxyacetophenone, 2-methyl-1-(4-(methylthio)phenyl)-2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butane-1-one, and a mixture thereof.

The benzophenone-based initiator may be benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-dichlorobenzophenone, 3,3'-dimethyl-2-methoxybenzophenone or a mixture thereof.

The thiothione-based initiator may be thiothione, 2-methylthiothione, isopropylthiothione, 2,4-diethylthiothione, 2,4-diisopropylthiothione, 2-chlorothiothione or a mixture thereof.

The benzoin-based initiator may be benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyl dimethyl ketal or a mixture thereof.

The phosphorus-based initiator may also be bis(benzoyl)phenylphosphine oxide, benzoyldiphenylphosphine oxide or a mixture thereof.

The oxime system may also be 2-(o-benzoyloxime)-1-[4-(phenylthio)phenyl]-1,2-octanedione and 1-(o-acetyloxime)-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone, or a mixture thereof.

The aforementioned photopolymerization initiator is preferably contained in the sealing composition of the present invention in a range of about 0.1 to 20 parts by mass relative to 100 parts by mass of the total of the aforementioned photopolymerizable monomer and the photopolymerization initiator. By setting it within the aforementioned range, photopolymerization can be fully initiated during exposure, and after photopolymerization, the transmittance can be prevented from being reduced due to the remaining unreacted initiator. Specifically, the aforementioned photopolymerization initiator is preferably contained in a range of 0.5 to 10 parts by mass, more specifically, in a range of 1 to 5 parts by mass. In addition, the aforementioned photopolymerization initiator is preferably contained in the sealing composition of the present invention in a range of 0.1 to 10% by mass based on the solid content, and more preferably in a range of 0.1 to 5% by mass. By setting it within the above range, photopolymerization can be fully initiated, and the reduction of transmittance due to residual unreacted initiator can be prevented.

In addition, instead of the above-mentioned photopolymerization initiator, a photoacid generator or photopolymerization initiator of a carbazole series, a diketone series, a cobalt series, an iodine series, a diazo series, a biimidazole series, or the like may be used.

<Other additives> The sealing composition of the present invention further contains other ingredients including antioxidants, heat stabilizers, photosensitizers, dispersants, thermal crosslinking agents and surfactants within the scope of obtaining the effects of the present invention. These ingredients may be contained in the sealing composition of the present invention in one kind or in two or more kinds.

The aforementioned antioxidant can improve the thermal stability of the sealing layer. The antioxidant may also include one or more selected from the group consisting of phenol, quinone, amine and phosphite, but is not limited to these. For example, as an antioxidant, tetrakis[methylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate)]methane, tris(2,4-di-tert-butylphenyl)phosphite, etc. can be cited.

The antioxidant is preferably contained in the sealing composition in an amount of 0.01 to 3 parts by mass, more preferably 0.01 to 1 part by mass, relative to 100 parts by mass of the total of the photopolymerizable monomer and the photopolymerization initiator. By setting the amount within the above range, excellent thermal stability can be exhibited.

The aforementioned heat stabilizer is contained in the sealing composition to suppress the viscosity change of the sealing composition at room temperature, and a conventional heat stabilizer can be used without limitation. For example, a sterically resistant heat stabilizer can be used as a heat stabilizer. The phenolic heat stabilizer may include poly(dicyclopentadiene-co-p-cresol), octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,6-di-tert-butyl-4-methylphenol, 2,2'-methane-bis(4-methyl-6-tert-butyl-phenol), 6,6'-di-tert-butyl-2,2'-thiodi-p-cresol, tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, triethylene glycol bis(3-tert-butyl-4-hydroxy-5-methylphenyl), 4,4'-thiobis(6-tert-butyl-m-cresol), 3 ,3'-bis(3,5-di-tert-butyl-4-hydroxyphenyl)-N,N'-hexamethylene-bispropionamide, pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate), stearyl-3,5-di-tert-butyl-4-hydroxyphenyl propionate, pentaerythritol tetrakis(1,3,5-tris(2,6-dimethyl-3-hydroxy-4-tert-butyl-benzyl) isocyanurate, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris(2-hydroxyethyl) isocyanurate-tris(3,5-di-tert-butyl hydroxyphenyl propionate), but not limited thereto.

The thermal stabilizer is contained in the sealing composition in an amount of less than 2000 ppm, preferably in a range of 0.01 to 2000 ppm, and more preferably in a range of 100 to 1000 ppm, based on the solid content, relative to the total of the photopolymerizable monomer and the photopolymerization initiator. By setting the thermal stabilizer within the above range, the storage stability and processability of the sealing composition in a liquid state can be improved.

The aforementioned photosensitizer has the function of transferring the absorbed light energy to the photopolymerization initiator. Therefore, even if the photopolymerization initiator used does not absorb the light from the light source, it can still have the original photopolymerization initiator function. It is such a compound. As photosensitizers, for example, anthracene derivatives such as 9,10-dibutoxyanthracene; benzoin derivatives such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; benzophenone, o-benzoylbenzoic acid methyl ester, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, 2,4,6-trimethylbenzophenone, 4-benzoyl-N, Benzophenone derivatives such as N-dimethyl-N-[2-(1-oxo-2-propenyloxy)ethyl]benzyl ammonium bromide and (4-benzoylbenzyl)trimethylammonium chloride; 2-isopropylthioxanone, 4-isopropylthioxanone, 2,4-diethylthioxanone, 2,4-dichlorothioxanone, 1-chloro-4-propoxythioxanone, 2-(3-dimethylamino-2-hydroxy)-3,4-dimethyl-9H-thioxanone-9-one chloride; and other compounds. Among them, anthracene derivatives, benzoin derivatives, benzophenone derivatives, anthraquinone derivatives, and thioxanone derivatives are preferred.

<Ultraviolet curing> As the ultraviolet rays irradiated to cure the sealing composition of the present invention, known means can be used, and there is no particular limitation as long as the ultraviolet rays are irradiated in the range of 200 to 400 nm to cure. Ideally, from the viewpoint of preventing the degradation of electronic devices, it is preferable to use a 395 nm LED. As for the environment for irradiating ultraviolet rays, known means can be used as long as the sealing composition can be cured, and there is no particular limitation as long as the ultraviolet rays can be cured. Ideally, from the viewpoint of preventing the degradation of electronic components and preventing the influence of oxygen that hinders the curing, it is preferable to irradiate in an inert gas environment. In particular, it is preferable to irradiate in a nitrogen or argon atmosphere.

<Physical properties> The viscosity of the sealing composition of the present invention is in the range of 3 to 30 mPa·s, which is preferable from the viewpoint of further improving the ejection property of the inkjet head. The surface tension is greater than 15 mN/m and less than 45 mN/m, which is preferable from the viewpoint of further improving the ejection property of the inkjet head.

The viscosity of the sealing composition of the present invention can be obtained by measuring the temperature change of the dynamic viscoelasticity of the sealing composition, for example, using various rheometers. In the present invention, these viscosities are values obtained by the following method. The sealing composition of the present invention is placed in a stress-controlled rheometer Physica MCR300 (diameter of cone plate: 75 mm, cone angle: 1.0°), manufactured by Anton Paar. Next, the sealing composition is heated to 100°C, and the sealing composition is cooled to 20°C under the conditions of a cooling rate of 0.1°C/s, a distortion of 5%, and an angular frequency of 10 radian/s, to obtain a temperature change curve of the dynamic viscoelasticity.

The sealing composition of the present invention may also contain pigment particles. From the perspective of further improving the ejection performance of the inkjet head, the average particle size of the pigment particles when the sealing composition of the present invention contains pigment is preferably in the range of 0.08 to 0.5 μm, and the maximum particle size is preferably in the range of 0.3 to 10 μm. The average particle size of the pigment particles in the present invention means the value obtained by the dynamic light scattering method using Zetasizer Nano ZSP, manufactured by Malvern. In addition, since the sealing composition containing the coloring material has a high concentration and light cannot penetrate in the measuring machine, the sealing composition is diluted 200 times and then measured. The measuring temperature is set to room temperature (25°C).

Furthermore, the sealing composition of the present invention is such that the Ohnesorg number (Oh) shown in the following formula 1, where the density ρ, the surface tension σ of the sealing composition, the viscosity μ of the sealing composition, and the nozzle diameter D ₀ , falls within the range of 0.1 to 1, which is preferable from the viewpoint of the ejection properties of the inkjet and the stabilization of the droplets during the flight of the ink.

The sealing composition of the present invention is prepared to provide a hardened polymer having a Tg (glass transition point) of 80°C or higher in the film after polymerization. The Tg of the film after polymerization is preferably 80°C or higher from the perspective of ensuring stability in the formation process of the electronic device, the driving temperature, and the reliability test.

[Method for forming a sealing film for an electronic device] The method for forming a sealing film for an electronic device of the present invention is a method for forming a sealing film using the aforementioned electronic device sealing composition of the present invention, and is characterized by comprising: a process of forming a first sealing layer on an electronic device by a vapor phase method; and a process of forming a second sealing layer by applying the aforementioned electronic device sealing composition on the aforementioned first sealing layer. In addition, a process of forming a third sealing layer on the aforementioned second sealing layer by a vapor phase method is provided, which is preferable from the viewpoint of being able to further improve the sealing performance of the electronic device.

<First Sealing Layer Formation Process> The first sealing layer formation process is to form the first sealing layer on the electronic device by a vapor phase method. As the gas phase method, there can be cited: sputtering method (for example, reactive sputtering method including magnetron cathode sputtering, planar magnetron sputtering, diode AC planar magnetron sputtering, diode AC rotary magnetron sputtering, etc.), evaporation method (for example, resistance heating evaporation, electron beam evaporation, ion beam evaporation, plasma supported evaporation, etc.), thermal CVD method, catalytic chemical vapor phase growth method (Cat-CVD), capacitive coupled plasma CVD method (CCP-CVD), photo CVD method, plasma CVD method (PECVD), epitaxial growth method, atomic layer growth method (ALD) and other chemical evaporation methods, etc. Among them, formation by ALD method and CVD method is preferred. The first sealing layer contains silicon nitride (SiNx), silicon oxynitride (SiNOx) or silicon oxide (SiOx). A specific example of forming the first sealing layer is a method of reducing the pressure in a chamber and supplying silane ( _SiH4 ), ammonia ( _NH3 ) and hydrogen ( _H2 ) as raw material gases into the chamber after heating. The thickness of the first sealing layer is preferably in the range of 10 to 1000 nm, more preferably in the range of 100 to 500 nm.

<Second sealing layer forming process> The second sealing layer forming process is to form the second sealing layer by applying the aforementioned sealing composition of the present invention on the aforementioned first sealing layer. Specifically, it may also be a process comprising: applying the aforementioned sealing composition on the aforementioned first sealing layer (coating process), and subjecting the obtained coating film to vacuum ultraviolet irradiation in a nitrogen atmosphere for modification.

(Coating process) As a coating method for the sealing composition, any appropriate method can be adopted, for example: spin coating, roller coating, flow coating, inkjet coating, inkjet coating, printing, dip coating, casting film forming, rod coating, gravure printing, etc. Among them, the inkjet method is used, which is preferred from the perspective of being able to perform fine patterning as required when sealing electronic devices such as organic EL elements.

As the inkjet method, a known method can be used. The inkjet method can be roughly divided into two types: the on-demand drip method and the continuous method, and both can be used. The on-demand drip method includes an electro-mechanical conversion method (such as a single-chamber type, a double-chamber type, an elbow type, a piston type, a common mode type, a common wall type, etc.), an electro-thermal conversion method (such as a thermal inkjet type, a bubble jet (registered trademark) type, etc.), an electrostatic attraction method (such as an electric field control type, a slit jet type, etc.) and a discharge method (such as a flash jet type, etc.). From the perspective of the cost or productivity of the inkjet head, it is better to use a head using an electro-mechanical conversion method or an electro-thermal conversion method. In addition, the method of dripping liquid (such as coating liquid) is sometimes called "ink jet method" in conjunction with the ink jet method.

When applying the sealing composition, it is preferably done under a nitrogen atmosphere.

(Modification process) In the aforementioned modification process, after the coating process, the obtained coating film may be subjected to vacuum ultraviolet irradiation in a nitrogen atmosphere for modification. The so-called modification process is a conversion reaction of polysilazane to silicon oxide or silicon oxynitride. The modification process is also carried out in a nitrogen atmosphere or under reduced pressure in a glove box. The modification process in the present invention can be selected from known methods based on the conversion reaction of polysilazane. In the present invention, a conversion reaction using plasma, ozone or ultraviolet rays that can perform the conversion reaction at low temperature is preferred. Plasma or ozone can be used by previously known methods. In the present invention, the coating film is provided and irradiated with vacuum ultraviolet light (also called VUV) with a wavelength below 200nm to perform a modification treatment to form the second sealing layer described in the present invention.

The thickness of the second sealing layer is preferably in the range of 0.5 to 20 μm, more preferably in the range of 3 to 10 μm. In the second sealing layer, the entire layer may be a modified layer, but the thickness of the modified layer is preferably in the range of 1 to 50 nm, more preferably in the range of 1 to 30 nm.

In the above-mentioned process of irradiating vacuum ultraviolet rays for modification, the illumination of the vacuum ultraviolet rays received by the coating film on the coating film surface 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 illumination of the vacuum ultraviolet rays to be above 30 mW/cm ² , the modification efficiency can be fully improved. When it is below 200 mW/cm ² , the occurrence rate of damage to the coating film can be greatly reduced, and the damage to the substrate can also be reduced, so it is preferred.

The irradiation energy of vacuum ultraviolet rays on the coating film surface is preferably in the range of 1 to 10 J/ ^cm2. From the perspective of maintaining the insulation and moisture and heat resistance required for the dehumidification function, it is preferably in the range of 3 to 7 J/ ^cm2 .

In addition, as a light source of vacuum ultraviolet light, a rare gas excimer lamp can be used ideally. Vacuum ultraviolet light is easily reduced in efficiency during vacuum ultraviolet light irradiation due to the presence of oxygen absorption, so vacuum ultraviolet light irradiation is preferably carried out under a state of low oxygen concentration as much as possible. That is, the oxygen concentration during vacuum ultraviolet light irradiation is preferably set in the range of 10 to 10000 ppm, preferably in the range of 50 to 5000 ppm, more preferably in the range of 80 to 4500 ppm, and most preferably in the range of 100 to 1000 ppm.

The reforming treatment can also be combined with the heat treatment. The heating conditions are preferably in the range of 50 to 300°C, preferably in the range of 60 to 150°C, and preferably in the range of 1 second to 60 minutes, preferably in the range of 10 seconds to 10 minutes. By combining the heat treatment, the dehydration condensation reaction during reforming can be promoted, and the reformed body can be formed more efficiently.

As the heat treatment, for example, there can be cited a method of heating the coating by heat conduction by bringing the substrate into contact with a heating element such as a heating block, a method of heating the atmosphere by an external heater such as a resistance wire, a method of using infrared light such as an IR heater, etc., but there are no particular limitations. In addition, a method that can maintain the smoothness of the coating containing the silicon compound can be appropriately selected.

<Third Sealing Layer Formation Process> The third sealing layer formation process is to form the third sealing layer on the second sealing layer by a vapor phase method. As the gas phase method, similar to the gas phase method used in the process of forming the first sealing layer, there can be cited: sputtering method (for example, reactive sputtering method including magnetron cathode sputtering, planar magnetron sputtering, diode AC planar magnetron sputtering, diode AC rotary magnetron sputtering, etc.), evaporation method (for example, resistance heating evaporation, electron beam evaporation, ion beam evaporation, plasma supported evaporation, etc.), thermal CVD method, catalytic chemical vapor phase growth method (Cat-CVD), capacitive coupled plasma CVD method (CCP-CVD), photo CVD method, plasma CVD method (PE-CVD), epitaxial growth method, chemical evaporation method such as atomic layer growth method (ALD), etc. Among them, it is preferably formed by the ALD method or the CVD method. The third sealing layer contains silicon nitride (SiNx), silicon oxynitride (SiNOx) or silicon oxide (SiOx). As a specific example of forming the third sealing layer, there is a method in which the pressure in the chamber is first reduced, and silane ( _SiH4 ), ammonia ( _NH3 ), and hydrogen ( _H2 ) are heated and then supplied into the chamber as raw material gases. The thickness of the third sealing layer is preferably in the range of 10 to 1000 nm, and more preferably in the range of 100 to 500 nm.

In addition, as mentioned above, after the sealing film is formed, a conductive film for a touch sensor can be further formed. The conductive film can be formed by a graphene film with excellent flexibility, a metal nanowire film (e.g., a film containing silver nanowires or copper nanowires), or a metal nanoparticle film (e.g., a film containing silver nanoparticles or copper nanoparticles) in addition to a metal compound film such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide). In addition, it can also be formed by a multilayer film of multiple metals such as Al film/Ti film/Al film.

[Electronic device sealing film] An electronic device sealing film according to one embodiment of the present invention is an electronic device sealing film for sealing an electronic device by curing an electronic component sealing composition containing a photopolymerizable monomer and a photopolymerization initiator, wherein the photopolymerizable monomer contains (meth)acrylate; the refractive index of the electronic device sealing film at a wavelength of 380 nm is in the range of 1.45 to 1.56; and the extinction coefficient of the electronic device sealing film at a wavelength of 380 nm is in the range of 50×10 ^-5 to 200×10 ^-5 . Furthermore, another aspect of the electronic device sealing film of the present invention is an electronic device sealing film for sealing an electronic device, and is characterized in that it has: a first sealing layer containing: silicon nitride, silicon oxide or silicon oxynitride; and a second sealing layer using the electronic device sealing composition of the present invention. Such an electronic device sealing film of the present invention is formed by the aforementioned electronic device sealing film forming method. That is, the second sealing layer is formed using the electronic device sealing composition of the present invention. The refractive index of the aforementioned second sealing layer at a wavelength of 380 nm is in the range of 1.45 to 1.56, and the extinction coefficient at a wavelength of 380 nm is in the range of 50×10 ^-5 to 200×10 ^-5 . Furthermore, the electronic device sealing film of the present invention preferably further comprises a third sealing layer containing silicon nitride, silicon oxide or silicon oxynitride on the second sealing layer.

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

<Second sealing layer> The second sealing layer is provided adjacent to the first sealing layer and is formed by applying the sealing composition on the first sealing layer. Therefore, the second sealing layer contains a polymer composed of a specific photopolymerizable monomer contained in the sealing composition.

As a method for detecting that the second sealing layer contains the polymer, various previously known analytical methods can be used, such as chromatography, infrared spectroscopy, ultraviolet-visible spectroscopy, nuclear magnetic resonance analysis, X-ray diffraction, mass spectrometry, X-ray photoelectron spectroscopy, etc.

The content of the polymer in the second sealing layer is preferably in the range of 85 to 100 mass %, more preferably in the range of 90 to 95 mass %.

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

[Electronic device] In the electronic device sealing film forming method and electronic device sealing film of the present invention, the electronic device to be sealed can be, for example, an organic EL element, an LED element, a liquid crystal display element (LCD), a thin film transistor, a touch panel, an electronic paper, a solar cell (PV), etc. From the perspective of more efficiently obtaining the effect of the present invention, an organic EL element, a solar cell or an LED element is preferred, and an organic EL element is particularly preferred.

<Organic EL element> The organic EL element used as the electronic device described in the present invention may also be a bottom emission type, that is, light is extracted from the transparent substrate side. Specifically, the bottom emission type is formed by sequentially stacking a transparent electrode as a cathode, a light-emitting functional layer, and a counter electrode as an anode on a transparent substrate. In addition, the organic EL element described in the present invention may also be a top emission type, that is, light is extracted from the side of the transparent electrode as a cathode opposite to the substrate. Specifically, the top emission type is a structure in which a counter electrode serving as an anode is set on the substrate side, and a light-emitting functional layer and a transparent electrode serving as a cathode are sequentially stacked on its surface.

The following discloses a representative example of the structure of an organic EL element. (i) Anode/hole injection transport layer/luminescent layer/electron injection transport layer/cathode (ii) Anode/hole injection transport layer/luminescent layer/hole blocking layer/electron injection transport layer/cathode (iii) Anode/hole injection transport layer/electron blocking layer/luminescent layer/hole blocking layer/electron injection transport layer/cathode (iv) Anode/hole injection layer/hole transport layer/luminescent layer/electron transport layer/electron injection layer/cathode (v) Anode/hole injection layer/hole transport layer/luminescent layer/hole blocking layer/electron transport layer/electron injection layer/cathode (vi) Anode/hole injection layer/hole transport layer/electron blocking layer/luminescent layer/hole blocking layer/electron transport layer/electron injection layer/cathode Furthermore, the organic EL element may also have a non-luminescent intermediate layer. The intermediate layer may also be a charge generating layer or may be composed of a multi-photon unit. As for the outline of the organic EL element applicable to the present invention, for example, Japanese Patent Publication No. 2013-157634, Japanese Patent Publication No. 2013-168552, Japanese Patent Publication No. 2013-177361, Japanese Patent Publication No. 2013-187211, Japanese Patent Publication No. 2013-191644, Japanese Patent Publication No. 2013-191804, Japanese Patent Publication No. 2013-225678, Japanese Patent Publication No. 2013-235994, Japanese Patent Publication No. 2013- The structure described in Japanese Patent Publication No. 243234, Japanese Patent Publication No. 2013-243236, Japanese Patent Publication No. 2013-242366, Japanese Patent Publication No. 2013-243371, Japanese Patent Publication No. 2013-245179, Japanese Patent Publication No. 2014-003249, Japanese Patent Publication No. 2014-003299, Japanese Patent Publication No. 2014-013910, Japanese Patent Publication No. 2014-017493, Japanese Patent Publication No. 2014-017494, etc.

<Substrate> As a substrate that can be used in the above-mentioned organic EL element (hereinafter also referred to as a supporting substrate, substrate, substrate, support, etc.), specifically, glass or resin film is preferably used. When flexibility is required, resin film is preferred. In addition, it can be transparent or opaque. In the case of a bottom emission type in which light is extracted from the substrate side, the substrate is preferably transparent.

Preferred resins include polyester resins, methacrylic acid resins, methacrylic acid-maleic acid copolymers, polystyrene resins, transparent fluorine resins, polyimide, fluorinated polyimide resins, polyamide resins, polyamide imide resins, polyether imide resins, cellulose acylate resins, polyamine resins, A base material of a thermoplastic resin such as formate resin, polyetheretherketone resin, polycarbonate resin, alicyclic polyolefin resin, polyacrylate resin, polyethersulfone resin, polysulfone resin, cycloolefin copolymer, fluorene ring-modified polycarbonate resin, alicyclic modified polycarbonate resin, fluorene ring-modified polyester resin, acrylic compound, etc. The resin may be used alone or in combination of two or more.

The substrate is preferably made of a heat-resistant material. Specifically, a substrate having a linear expansion coefficient of 15ppm/K to 100ppm/K and a glass transition temperature (Tg) of 100°C to 300°C is used. This substrate meets the necessary conditions for use in electronic components and as a laminated film for displays. 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 will be unstable during the process at the above-mentioned temperature, and it will be accompanied by thermal expansion and contraction, resulting in the disadvantage of deterioration of the shielding performance, or the disadvantage of being unable to withstand the heat process. When the concentration is less than 15ppm/K, the film will break like glass, resulting in deterioration of flexibility.

The Tg or linear expansion coefficient of the substrate can be adjusted by additives, etc. Preferred specific examples of thermoplastic resins that can be used as substrates include polyethylene terephthalate (PET: 70°C), polyethylene naphthalate (PEN: 120°C), polycarbonate (PC: 140°C), alicyclic polyolefins (e.g., ZEONOR manufactured by Zeon Corporation of Japan) and polyolefins (e.g., ZEONOR manufactured by Zeon Corporation of Japan). (Registered trademark) 1600: 160°C), polyacrylate (PAr: 210°C), polyether sulfone (PES: 220°C), polysulfone (PSF: 190°C), cycloolefin copolymer (COC: compound described in Japanese Patent Application Laid-Open No. 2001-150584: 162°C), polyimide (e.g. NEOPULIM manufactured by Mitsubishi Gas Chemical Co., Ltd. (Registered trademark: 260°C) , fluorene ring modified polycarbonate (BCF-PC: compounds described in Japanese Patent Publication No. 2000-227603: 225°C), alicyclic modified polycarbonate (IP-PC: compounds described in Japanese Patent Publication No. 2000-227603: 205°C), acryl compounds (compounds described in Japanese Patent Publication No. 2002-80616: above 300°C), etc. (temperatures in parentheses represent Tg).

The electronic device described in the present invention is an electronic device such as an organic EL element, so the substrate is preferably transparent. That is, the light transmittance is usually above 80%, preferably above 85%, and more preferably above 90%. The light transmittance is measured using the method described in JIS K7105:1981, that is, using an integrating sphere light transmittance measuring device to measure the total light transmittance and the amount of scattered light, and can be calculated by subtracting the diffused transmittance from the total light transmittance.

Furthermore, the substrates listed above may be unstretched films or stretched films. The substrates may be manufactured by a conventional method known in the art. The manufacturing methods of these substrates may be appropriately described in paragraphs "0051" to "0055" of International Publication No. 2013/002026.

The surface of the substrate may be subjected to various known treatments required for adhesion, such as corona discharge treatment, flame treatment, oxidation treatment, or plasma treatment, and the above treatments may be combined as needed. In addition, the substrate may be subjected to an easy-to-adhesion treatment.

The substrate may be a single layer or a multilayer structure of two or more layers. When the substrate is a multilayer structure of two or more layers, each substrate may be of the same type or of different types.

The thickness of the substrate of the present invention (the total thickness in the case of a multilayer structure with more than two layers) is preferably 10 to 200 μm, more preferably 20 to 150 μm.

In the case of a film substrate, a film substrate with a gas barrier layer is preferred.

The gas barrier layer for the film substrate may be an inorganic, organic film or a mixed film of the two formed on the surface of the film substrate. Preferably, the gas barrier layer has a water vapor permeability (25±0.5°C, relative humidity (90±2)%RH) of 0.01g/m ² ･24h or less as measured in accordance with the method of JIS K 7129-1992. More preferably, the gas barrier layer has an oxygen permeability of 1×10 ^-3 mL/m ² ･24h･atm or less as measured in accordance with the method of JIS K 7126-1987 and a water vapor permeability of 1×10 ^-3 g/m ² ･24h or less.

The gas barrier layer may be formed of any material capable of inhibiting the penetration of moisture, oxygen, or other substances that may cause device degradation. Examples of the materials that may be used include silicon monoxide, silicon dioxide, silicon nitride, silicon oxynitride, silicon carbide, and silicon oxycarbide.

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 oxycarbide, etc., the inorganic material is sputtered (such as magnetron cathode sputtering, planar magnetron sputtering, diode AC planar magnetron sputtering, diode AC rotary magnetron sputtering, etc.), evaporation (such as resistance heating evaporation, electron beam evaporation, etc.) The layer formation is preferably performed by chemical evaporation methods such as evaporation, ion beam evaporation, plasma supported evaporation, etc.), thermal CVD, catalytic chemical vapor deposition (Cat-CVD), capacitive coupled plasma CVD (CCP-CVD), photo CVD, plasma CVD (PE-CVD), epitaxial growth, atomic layer deposition (ALD), reactive sputtering, etc.

Furthermore, after a coating liquid containing an inorganic precursor such as polysilazane, tetraethyl orthosilicate (TEOS), etc. is coated on a support, it is modified by irradiation with vacuum ultraviolet light to form an inorganic gas insulation layer, or the inorganic gas insulation layer can be formed by a thin film metallization technique such as metal plating on a resin substrate to bond a metal foil to the resin substrate.

Furthermore, the inorganic gas barrier layer may include an organic layer including an organic polymer. In other words, the inorganic gas barrier layer may be a laminate of an inorganic layer including an inorganic material and an organic layer.

The organic layer is formed, for example, by coating an organic monomer or an organic oligomer on a resin substrate to form a layer, and then polymerizing and crosslinking as needed using, for example, an electron beam device, a UV light source, a discharge device, or other suitable devices. Alternatively, for example, an organic monomer or an organic oligomer that can be flash evaporated and crosslinked by radiation is evaporated to form a polymer from the organic monomer or an organic oligomer. The coating efficiency can be improved by cooling the resin substrate.

Examples of coating methods for the organic monomer or the organic oligomer include roll coating (e.g., gravure roll coating), spray coating (e.g., electrostatic spray coating), etc. Examples of laminates of inorganic layers and organic layers include laminates described in International Publication No. 2012/003198 and International Publication No. 2011/013341.

In the case of an inorganic layer and an organic layer laminate, 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. [Example]

The following examples are given to specifically illustrate the present invention, but the present invention is not limited to these examples. In addition, in the following examples, unless otherwise stated, the operations are all carried out at room temperature (25° C.). In addition, unless otherwise stated, "%" and "parts" mean "mass %" and "mass parts" respectively.

[Monomer] The monomers used in the preparation of the sealing composition are shown below. The HOMO and LUMO values of each monomer are calculated by the method described below and are shown in the following Table I. Then, the refractive index (nd25) of the D line at 25°C is calculated for each monomer using an Abbe refractometer and is shown in the following Table I.

[Preparation of Sealing Compositions 1 to 28] Each monomer was weighed in a nitrogen atmosphere in the manner of the type and mass fraction shown in Table II below. Furthermore, 5 mass fractions of a phosphorus-based initiator (Omnirad 819 manufactured by IGM) as a photopolymerization initiator and 0.5 mass fractions of 2-isopropylthioxanone (manufactured by Merck) as a sensitizer were placed in a brown bottle and stirred on a heating plate at 65°C for 3 hours to obtain each sealing composition 1 to 28.

[Refractive index n and extinction coefficient k] A coating of the sealing composition was prepared on a glass substrate having a size of 50 mm × 50 mm in a nitrogen atmosphere so as to have a thickness of 100 nm. The coating was irradiated with ultraviolet light (MZ 240mm 395nm UVLED manufactured by IST) at a wavelength of 395 nm under a nitrogen atmosphere at 300 mW/ ^cm2 so as to have an integrated light intensity of 1.5 J/ ^cm2 , and the coating was cured and used as a measurement sample. The refractive index and extinction coefficient of the sample at 250 nm to 800 nm were measured using a UVSEL/FUV-FGMS spectro-elliptical polarimeter manufactured by HORIBA JYOBIN-YVON Co., Ltd., and the refractive index n at 380 nm and the extinction coefficient k at 380 nm of the cured film of the sealing composition were obtained and are shown in Table III below. Then, the ratio k/n of the extinction coefficient k at 380 nm to the refractive index n at 380 nm was obtained and is shown in Table III below.

[Average number of double bonds] The average number of double bonds is calculated as follows using the mass ratio w of each monomer when the number of double bonds contained in each monomer is d and the total mass of all monomers is 1, and is shown in the following Table III. Average number of double bonds = d1×w1+d2×w2+… (The suffixes d and w represent the monomer numbers.)

[Energy levels of HOMO and LUMO] Based on the information of the chemical structure, the HOMO and LUMO (unit: eV) of each monomer were obtained using Gaussian software manufactured by HULINKS. In the calculation, B3LYP was used as a functional. The HOMO and LUMO values of each monomer are shown in Table II. Based on the obtained HOMO and LUMO values of each monomer, the average value of HOMO and the average value of LUMO were calculated by the following formula, and the energy gap (Gap) was calculated based on the average value of HOMO and the average value of LUMO, which is shown in the following Table III. Average value of HOMO = HOMO1×w1+HOMO2×w2+・・・ Average value of LUMO = LUMO1×w1+LUMO2×w2+・・・ In the above formula, w represents the mass ratio of each monomer mentioned above. In addition, the suffixes of w, HOMO and LUMO represent the monomer number. Gap (unit: eV) = average value of LUMO - average value of HOMO

[Fabrication of organic EL elements] (1) Preparation of substrates A 15 μm polyimide film was prepared as a thin film substrate. Then, a gas barrier layer for a thin film substrate (SiO ₂ film: 250 nm/SiNx film: 50 nm/SiO ₂ film: 500 nm (upper layer/middle layer/lower layer)) was formed on the polyimide film by plasma CVD.

(2) Formation of the first electrode An Al film was formed as the first electrode (metal layer) on one surface of the substrate under the following conditions. The thickness of the formed first electrode was 150 nm. The thickness of the first electrode was the value measured by a contact surface profile meter (DECTAK). The Al film was formed by using a tungsten resistance heating crucible after reducing the pressure to a vacuum degree of 1×10 ^-4 Pa using a vacuum evaporation device.

(3) Formation of organic EL layer First, each of the evaporation crucibles in the vacuum evaporation device is filled with the following materials constituting each layer of the organic functional layer in an amount most suitable for the production of each element. The evaporation crucible is made of a resistive heating material made of molybdenum or tungsten.

(3-1) Formation of Hole Injection Layer 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 a hole injection layer with a thickness of 10 nm was formed on the first electrode (metal layer side) at an evaporation rate of 0.1 nm/sec.

(3-2) Formation of hole transport layer Next, the evaporation crucible containing the following compound M-2 was energized and heated, and evaporation was performed on the hole injection layer at an evaporation rate of 0.1 nm/sec to form a hole transport layer with a thickness of 30 nm.

(3-3) Formation of luminescent layer Next, the following compound BD-1 and the following compound H-1 were co-deposited at a deposition rate of 0.1 nm/sec so that the concentration of compound BD-1 was 7% by mass, thereby forming a luminescent layer (fluorescent luminescent layer) having a thickness of 15 nm and emitting blue light. Next, the following compound GD-1, the following compound RD-1, and the following compound H-2 were co-deposited at a deposition rate of 0.1 nm/sec so that the concentration of compound GD-1 was 20% by mass and the concentration of RD-1 was 0.5% by mass, thereby forming a luminescent layer (phosphorescent luminescent layer) having a thickness of 15 nm and emitting yellow light.

(3-4) Formation of electron transport layer Subsequently, a heating boat containing the following compound T-1 as an electron transport material was energized to form an electron transport layer made of Alq ₃ (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/sec and the thickness was set to 30 nm.

(3-5) Formation of electron injection layer (metal affinity layer) Next, the heating boat containing the following compound I-1 as an electron injection material is energized and heated to form an electron injection layer made of Liq on the electron transport layer. At this time, the evaporation rate is set to a range of 0.01 to 0.02 nm/sec, and the thickness is set to 2 nm. In addition, the electron injection layer functions as a metal affinity layer. In this way, an organic EL layer that emits white light is formed.

(4) Formation of the second electrode Then, a Mg/Ag mixture (Mg:Ag=1:9 (vol ratio)) was evaporated to a thickness of 10nm to form the second electrode and its extraction electrode.

(5) Formation of a capping layer Afterwards, the film was transferred to the original vacuum chamber, and α-NPD (4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl) was evaporated on the second electrode at a deposition rate of 0.1 to 0.2 nm/sec until the thickness reached 40 nm, forming a capping layer for improving the light extraction amount.

(6) Formation of the first sealing layer Next, as the first sealing layer to cover the light-emitting portion of the organic EL element manufactured above, silicon nitride (SiNx, Vickers hardness HV900) with a thickness of 500 nm is formed by plasma CVD.

(7) Formation of the Second Sealing Layer Next, the sealing composition 1 prepared above was filled into an inkjet head (KM1024i-MHE-D manufactured by Konica Minolta) in a nitrogen atmosphere. Then, the organic EL element formed up to the first sealing layer was coated with the sealing composition 1 in a nitrogen atmosphere using an inkjet method so that the coating thickness reached 10 μm. Thereafter, ultraviolet light of a wavelength of 395 nm (MZ 240mm 395nm UVLED manufactured by IST) was irradiated at 300 mW/ ^cm2 so that the integrated light amount would be 1.5 J/ ^cm2 , thereby forming the second sealing layer.

(8) Formation of the third sealing layer Next, silicon nitride (SiNx, Vickers hardness HV900) was formed to a thickness of 500 nm on the second sealing layer as the third sealing layer by plasma CVD, and an organic EL element 1 for evaluation having the first to third sealing layers formed thereon was obtained.

[Production of organic EL elements 2 to 28] In the production of the aforementioned organic EL element 1, the sealing composition 1 used in the formation of the aforementioned second sealing layer was changed as shown in the following table, and organic EL elements 2 to 28 for evaluation were produced in the same manner.

[Evaluation] ＜Reliability test after bending (luminous efficiency)＞ The obtained sample of the organic EL element for evaluation was made to emit light, and the luminous efficiency (lm/W unit) was measured and regarded as the initial luminous efficiency. Afterwards, the evaluation sample was bent repeatedly 200,000 times at a bending radius of R=2.5mm at room temperature using a clamshell-type repeated bending tester (Tension-Free(R) Folding Clamshell-type desktop durability tester manufactured by YUASA). Afterwards, the luminous efficiency (lm/W unit) of the evaluation sample was measured and regarded as the luminous efficiency after bending, and the change rate of the luminous efficiency after bending relative to the initial luminous efficiency was evaluated, and the evaluation was made using the following evaluation criteria. Ratings 2 to 4 were considered acceptable. (Evaluation criteria) Rating 1: less than 80% Rating 2: more than 80% but less than 90% Rating 3: more than 90% but less than 95% Rating 4: more than 95%

<Crease after bending (evaluation of film deformation after folding resistance test)> A 15μm polyimide film was prepared as a film substrate. Then, a sealing layer was formed on the polyimide film in the same manner as the aforementioned (6) formation of the first sealing layer, (7) formation of the second sealing layer, and (8) formation of the third sealing layer, as an evaluation sample. The evaluation sample was bent with a bending radius of R = 2.0 mm so that the polyimide film side appeared convex. It was fixed in the bent state and kept in an environment of 85°C for 72 hours. The evaluation sample was taken out and the surface shape profile of the third sealing layer side was measured using a contact film thickness meter (Bruker dektak XT). If the film is deformed, observe the shape of the bumps and depressions, and evaluate the maximum height of the convex shape and the maximum depth of the concave shape, and judge using the following evaluation criteria. Ratings 2 to 4 are considered acceptable. (Evaluation criteria) Rating 1: Maximum height or maximum depth is 5μm or more Rating 2: Maximum height or maximum depth is 3μm or more but less than 5μm Rating 3: Maximum height or maximum depth is 1μm or more but less than 3μm Rating 4: Maximum height or maximum depth is less than 1μm

<Relative dielectric constant> A 50 μm thick film of the sealing composition was formed on a 100 mm × 100 mm release film substrate in a nitrogen environment. The film was cured by irradiating the film with 395 nm ultraviolet light (MZ 240 mm 395 nm UVLED manufactured by IST) at 300 mW/cm ² in a nitrogen environment so that the integrated light intensity would be 1.5 mJ/cm ^2. The cured film was peeled off from the release film, and then Ag films were formed on both sides by sputtering to prepare a measurement sample. The impedance of the sample was measured by an impedance measuring device (Solartron 126096) at a frequency of 100kHz and AC 0.1 (V), and the relative dielectric constant was measured. A relative dielectric constant of less than 2.9 was considered acceptable, and a relative dielectric constant of more than 2.9 was considered unacceptable.

As shown in the above results, it can be seen that the sealing composition of the present invention can obtain a sealing film with a good appearance after the reliability test in the folded state, excellent luminous efficiency after the folding reliability test, and low relative dielectric constant, compared with the sealing composition of the comparative example.

Claims (12)

An electronic device sealing composition is an electronic device sealing composition containing a photopolymerizable monomer and a photopolymerization initiator. The composition is characterized in that the photopolymerizable monomer contains (meth)acrylate. When the composition is cured by irradiating ultraviolet light with a wavelength of 395nm at 1.5Jcm ^-2 in a nitrogen environment, the refractive index of the formed electronic device sealing film at a wavelength of 380nm is in the range of 1.45-1.56, and the extinction coefficient of the electronic device sealing film at a wavelength of 380nm is in the range of 80× ^10-5 ~200× ^10-5 . As described in claim 1, the electronic device sealing composition, wherein the refractive index is in the range of 1.50 to 1.53. The electronic device sealing composition as recited in claim 1, wherein the extinction coefficient is in the range of 125×10 ^-5 to 200×10 ^-5 . The electronic device sealing composition as recited in claim 1, wherein the refractive index n and the extinction coefficient k satisfy the following relationship: k/n≧100×10 ^-5 . The electronic device sealing composition as described in claim 1, wherein the average double bond number of the photopolymerizable monomer contained in the electronic device sealing composition is 5 or less. The electronic device sealing composition as described in claim 1, wherein the energy levels of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of the photopolymerizable monomer contained in the electronic device sealing composition satisfy the following relationship: 5.9eV≦LUMO-HOMO≦6.5eV. An electronic device sealing film is used to seal an electronic device by curing an electronic component packaging composition containing a photopolymerizable monomer and a photopolymerization initiator, wherein the photopolymerizable monomer contains (meth)acrylate; the refractive index of the electronic device sealing film at a wavelength of 380 nm is in the range of 1.45 to 1.56, and the extinction coefficient of the electronic device sealing film at a wavelength of 380 nm is in the range of 80×10 ^-5 to 200×10 ^-5 . An electronic device sealing film is an electronic device sealing film for sealing an electronic device, characterized by having: a first sealing layer containing: silicon nitride, silicon oxide or silicon oxynitride; and a second sealing layer using an electronic device sealing composition as described in any one of claim 1 to claim 6. The electronic device sealing film as described in claim 8, wherein a third sealing layer is provided on the aforementioned second sealing layer, and the third sealing layer contains silicon nitride, silicon oxide or silicon oxynitride. A method for forming an electronic device sealing film is a method for forming an electronic device sealing film using an electronic device sealing composition as described in any one of claim 1 to claim 6, characterized by comprising: a process of forming a first sealing layer on an electronic device by a vapor phase method; and a process of forming a second sealing layer by applying the electronic device sealing composition on the first sealing layer. The method for forming a sealing film for an electronic device as described in claim 10 comprises: a process of forming a third sealing layer on the aforementioned second sealing layer by a vapor phase method. The method for forming a sealing film for an electronic device as described in claim 10, wherein the second sealing layer is formed by an inkjet method.