Electronic device encapsulation composition for inkjet, electronic device encapsulation film formation method, and electronic device encapsulation film

Abstract

An electronic device encapsulation composition according to the present invention is for an inkjet and contains a photopolymerizable monomer and a photopolymerization initiator, the composition containing a (meth)acrylate as the photopolymerizable monomer, and, as regards the dynamic viscoelasticity after curing of the electronic device encapsulation composition, the loss factor (tanδ) peak value is in the 0.3-1.0 range and the storage modulus (G') is in the 1.0-3.0 GPa range.

Description

Inkjet electronic device sealing composition, method for forming electronic device sealing film, and electronic device sealing film

[0001] The present invention relates to an inkjet composition for electronic device encapsulation, a method for forming an electronic device encapsulating film, and an electronic device encapsulating film. In particular, the present invention relates to a composition for electronic device encapsulation that can provide an electronic device encapsulating film having good adhesion, flexibility, and heat resistance.

[0002] Taking advantage of the characteristics of electronic devices, particularly organic electroluminescent devices, which can be made thinner and lighter, active research is being conducted on flexible organic electroluminescent devices. Hereinafter, organic electroluminescent devices are also referred to as "organic EL devices" or "organic EL elements."

[0003] Furthermore, in recent years, there has been an increasing demand for devices that are not flexible (bendable) but foldable (foldable) and rollable (rollable). As a result, the required flexibility of organic EL devices is becoming increasingly stringent. Generally, when a laminate constituting a device is bent, stress concentrates at the interface of the laminate. Therefore, as flexibility becomes more stringent, stress concentration at the interface can cause delamination of the laminate. To prevent delamination, it is necessary to improve the adhesion strength so that it can withstand more severe bending stress. Furthermore, as devices become thinner and lighter, it is becoming necessary to design devices that take into account the effect of heat generation on adhesion at the interface of the laminate.

[0004] Patent Document 1 discloses a technology for an ultraviolet-curable resin for encapsulating organic EL devices that can be formed by an inkjet method and that can easily produce a cured product with a low dielectric constant. However, when the present inventors examined the cured product on a film-like support substrate, they found that the peeling of the cured product became more pronounced as the flexibility increased. They also found that there was a problem with the adhesion of the cured product.

[0005] Patent Document 2 discloses a technology for a self-repairing resin composition that exhibits excellent curability with active energy rays. In particular, by using a urethane acrylamide in which the loss modulus (tan δ) of the cured product, measured by dynamic viscoelasticity, is specified within a predetermined range, a resin composition with excellent self-repairing properties, adhesion, and flexibility is provided. However, when the present inventors examined the resin composition, they found that it did not exhibit sufficient repeated bending performance, which is expected for foldable and rollable devices, and that it was problematic for application to flexible organic EL devices. Furthermore, because the self-repairing function utilizes ladder (zipper)-type crosslinking that utilizes the reversibility of intermolecular hydrogen bonds, the heat resistance was insufficient.

[0006] JP 2020-57580 A JP 2020-100821 A

[0007] The present invention has been made in view of the above problems and circumstances. The problem to be solved by the present invention is to provide a composition for encapsulating electronic devices that can provide an electronic device encapsulating film having good adhesion, flexibility, and heat resistance. The present invention also provides an electronic device encapsulating film using the composition for encapsulating electronic devices, and a method for forming the electronic device encapsulating film.

[0008] The present inventors have investigated the causes of the above problems in order to solve the above problems. They have found that an electronic device sealing film having good adhesion, flexibility, and heat resistance can be obtained by controlling the loss factor peak value and storage modulus of the dynamic viscoelasticity of the sealing composition after curing. That is, the above problems according to the present invention are solved by the following means.

[0009] 1. An inkjet electronic device encapsulating composition containing a photopolymerizable monomer and a photopolymerization initiator, wherein the photopolymerizable monomer is a (meth)acrylate, and the inkjet electronic device encapsulating composition has, after curing, dynamic viscoelasticity characteristics such that the loss factor (tan δ) peak value is in the range of 0.3 to 1.0 and the storage modulus (G') is in the range of 1.0 to 3.0 GPa.

[0010] 2. The composition for electronic device encapsulation for inkjet printing according to item 1, wherein the (meth)acrylate contains a monofunctional (meth)acrylate, and the content ratio of the monofunctional (meth)acrylate to the total amount of the photopolymerizable monomer is 41 mass % or more.

[0011] 3. The composition for electronic device sealing for ink jet printing according to item 1, wherein the (meth)acrylate has a phenyl group.

[0012] 4. In a nitrogen gas atmosphere, ultraviolet light with a wavelength of 395 nm is applied at 1.5 to 1.8 J / cm ２ 2. The ink-jet electronic device sealing composition according to claim 1, wherein when cured by irradiation, the resulting electronic device sealing film has a cure rate of 80% or more.

[0013] 5. A method for forming a sealing film using the composition for sealing an electronic device according to any one of items 1 to 4, comprising: forming a first sealing layer on an electronic device by a vapor phase method; and forming a second sealing layer by applying the composition for sealing an electronic device on the first sealing layer.

[0014] 6. The method for forming an electronic device sealing film according to claim 5, further comprising the step of forming a third sealing layer on the second sealing layer by a vapor phase method.

[0015] 7. The method for forming an electronic device sealing film according to item 5, wherein the step of forming the second sealing layer uses an inkjet method.

[0016] 8. An electronic device sealing film for sealing an electronic device, comprising: a first sealing layer containing silicon nitride, silicon oxide, or silicon oxynitride; and a second sealing layer formed using the electronic device sealing composition according to any one of items 1 to 4.

[0017] 9. The electronic device sealing film according to item 8, further comprising a third sealing layer on the second sealing layer, the third sealing layer containing silicon nitride, silicon oxide or silicon oxynitride.

[0018] The above-described means of the present invention can provide a composition for encapsulating electronic devices that can produce an electronic device encapsulating film having good adhesion, flexibility, and heat resistance. The above-described means of the present invention can also provide an electronic device encapsulating film using the composition for encapsulating electronic devices, and a method for forming an electronic device encapsulating film. The mechanism by which the effects of the present invention are exerted or the mechanism of action are not clearly understood, but are speculated as follows.

[0019] In the present invention, by setting the loss factor peak value within the range of 0.3 to 1.0, favorable adhesion and heat resistance can be obtained. It is presumed that this is because, by setting the loss factor peak value within this range, a balance is achieved between the components that store energy generated by external forces and strains inside the object and the components that diffuse it to the outside, thereby alleviating stress and heat loads as dissipated (thermal) energy. Furthermore, in the present invention, by setting the storage modulus (G') within the range of 1.0 to 3.0 GPa, the entanglement density of the molecular chains of the polymerized polymer increases, resulting in a high elastic modulus and favorable flexibility. Furthermore, the loss factor peak value and storage modulus can be set within preferred ranges by appropriately adjusting the film thickness and curing rate of the sealing film.

[0020] Furthermore, in the present invention, it is preferable that the (meth)acrylate contains a monofunctional (meth)acrylate. Since a monofunctional (meth)acrylate has one reactive group, the molecular weight variation of the polymer obtained upon polymerization is narrow. Narrow molecular weight variation leads to uniform thermal mobility of the polymer chain. It is generally known that the thermal mobility of the polymer chain corresponds to the peak value and waveform of the loss factor (tan δ) of dynamic viscoelasticity. Therefore, in order to set the loss factor peak value within the specific range, it is preferable to use a monofunctional (meth)acrylate in the present invention.

[0021] The electronic device encapsulating composition of the present invention is an inkjet electronic device encapsulating composition containing a photopolymerizable monomer and a photopolymerization initiator, wherein the photopolymerizable monomer is a (meth)acrylate, and the electronic device encapsulating composition has, after curing, a dynamic viscoelasticity such that the loss factor (tan δ) peak value is in the range of 0.3 to 1.0 and the storage modulus (G') is in the range of 1.0 to 3.0 GPa. This feature is a technical feature common to or corresponding to each of the following embodiments.

[0022] In an embodiment of the present invention, the (meth)acrylate preferably contains a monofunctional (meth)acrylate, and the content ratio of the monofunctional (meth)acrylate to the total amount of the photopolymerizable monomer is preferably 41 mass % or more. By setting the content ratio as described above, the density of entanglement of polymer molecular chains when the monofunctional (meth)acrylate is polymerized is increased, and the narrow molecular weight variation makes the thermal mobility of the polymer chains uniform, resulting in good adhesion, heat resistance, and flexibility.

[0023] The (meth)acrylate preferably has a phenyl group, which improves the heat resistance of the molecule and provides excellent adhesion, flexibility, and heat resistance.

[0024] Under a nitrogen gas atmosphere, ultraviolet light with a wavelength of 395 nm is applied at 1.5 to 1.8 J / cm ２ When cured by irradiation, the curing rate of the electronic device sealing film formed is preferably 80% or more from the viewpoint of adhesion.

[0025] (Adhesion) For example, when a CVD film is used as the base of a sealing film, peeling of the sealing film from the CVD film is thought to occur due to interfacial peeling and cohesive peeling. Interfacial peeling is related to the mechanical properties and film stress of the film. It is thought that by appropriately polymerizing and crosslinking the film, these mechanical properties are high and the film stress is within an appropriate range, resulting in good adhesion. Furthermore, by forming a sufficiently hardened film, the strength of the film itself is increased, and cohesive peeling can be suppressed. Therefore, in the present invention, by setting the curing rate of the sealing film to 80% or more, the mechanical properties of the film are improved, the film stress is within an appropriate range, and the adhesion is good. Furthermore, by forming a sufficiently hardened film, cohesive peeling can be suppressed.

[0026] The method for forming an electronic device encapsulating film of the present invention is a method for forming an encapsulating film using the electronic device encapsulating composition of the present invention, and includes the steps of forming a first encapsulating layer on an electronic device by a vapor phase method and forming a second encapsulating layer by applying the electronic device encapsulating composition on the first encapsulating layer, thereby obtaining an electronic device encapsulating film with good adhesion, flexibility, and heat resistance.

[0027] Furthermore, it is preferable to include a step of forming a third sealing layer on the second sealing layer by a vapor phase method, in terms of excellent sealing performance.

[0028] The step of forming the second sealing layer preferably uses an inkjet method, since this allows for highly accurate layer formation.

[0029] The electronic device sealing film of the present invention is an electronic device sealing film for sealing an electronic device, and includes a first sealing layer containing silicon nitride, silicon oxide, or silicon oxynitride, and a second sealing layer using the electronic device sealing composition, thereby providing an electronic device sealing film with good adhesion, flexibility, and heat resistance.

[0030] It is preferable to have a third sealing layer containing silicon nitride, silicon oxide or silicon oxynitride on the second sealing layer in terms of excellent sealing performance.

[0031] The present invention, its components, and embodiments and modes for carrying out the present invention will be described below. In this application, the symbol "to" is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0032] [Summary of Electronic Device Encapsulating Composition of the Present Invention] The electronic device encapsulating composition of the present invention is an inkjet electronic device encapsulating composition containing a photopolymerizable monomer and a photopolymerization initiator, wherein the photopolymerizable monomer contains a (meth)acrylate, and the electronic device encapsulating composition has, after curing, dynamic viscoelasticity such that the loss factor (tan δ) peak value is in the range of 0.3 to 1.0 and the storage modulus (G') is in the range of 1.0 to 3.0 GPa.

[0033] Hereinafter, the "composition for sealing electronic devices" may also be simply referred to as the "encapsulating composition." In this specification, "(meth)acrylate" refers to at least one of acrylate and methacrylate. Furthermore, the "electronic device" of the present invention refers to an element that generates, amplifies, converts, or controls an electrical signal by utilizing the kinetic energy, potential energy, or the like of electrons. Examples of such elements include active elements such as light-emitting diode elements, organic electroluminescence elements, photoelectric conversion elements, and transistors. Furthermore, in the present invention, passive elements that perform passive tasks such as "resisting" or "storing" external influences, such as resistors and capacitors, are also included in the electronic device. Therefore, the encapsulating composition of the present invention is used to form an encapsulating film for encapsulating the above-mentioned electronic device.

[0034] Regarding the dynamic viscoelasticity of the sealing composition of the present invention after curing, the loss factor (tan δ) peak value is in the range of 0.3 to 1.0. The loss factor peak value is preferably in the range of 0.6 to 0.8. Regarding the dynamic viscoelasticity of the sealing composition of the present invention after curing, the storage modulus (G') is in the range of 1.0 to 3.0 GPa. The storage modulus is preferably in the range of 2.4 to 2.7 GPa.

[0035] Here, the "loss factor (loss tangent)" is a physical property expressed as the ratio (G" / G') of the loss modulus G" to the storage modulus G'. Generally, the storage modulus G' (unit: GPa) represents elasticity and is an index of the force stored when deformed by an external force. In other words, the storage modulus G' is the elastic response component of the elastic modulus in the relationship between strain and stress when deformed, and energy corresponding to the work of deformation is stored. On the other hand, the "loss modulus G" (unit: GPa) represents viscosity and is an index of the force S lost as heat in response to the applied force when deformed by an external force. Furthermore, the "loss factor tanδ" is an index representing the balance between viscosity and elasticity. In other words, tanδ is a measure of the ratio of energy loss and storage relative to the work of deformation.

[0036] In this specification, the term "monofunctional (meth)acrylate" refers to a monomer having one (meth)acryloyl group in one molecule, and the term "polyfunctional (meth)acrylate" refers to a monomer having two or more (meth)acryloyl groups in one molecule.

[0037] Specifically, the monofunctional (meth)acrylate preferably has an aryl group including a phenyl group, a vinyl group, an alkyl group, a hydroxyl group, an aldehyde group, a carbonyl group, a carboxyl group, a nitro group, an amino group, a sulfo group, a halogeno group, an ether bond, an ester bond, etc. The content ratio of the monofunctional (meth)acrylate to the total amount of the photopolymerizable monomer is preferably within a range of 41 to 80% by mass, more preferably within a range of 45 to 70% by mass.

[0038] <Method of measuring the peak value of loss factor (tan δ) and storage modulus (G′)> It is preferable to use a conventionally commonly used method and measurement conditions for measuring dynamic viscoelasticity. For example, it is preferable to measure by the following method.

[0039] The dynamic viscoelasticity measuring device used was an RSA3 manufactured by TA Instruments. A tensile tool was used to mount the sample. As a sample, a coating film of the sealing composition with a thickness of 10 to 20 μm was prepared on a glass substrate having dimensions of 50 mm × 50 mm under a nitrogen environment. This coating film was then irradiated with 300 mW / cm under a nitrogen environment. ２ The cumulative light intensity is 1.0 to 1.8 J / cm ２ The coating was cured by irradiating it with ultraviolet light (MZ 240 mm 395 nm UVLED manufactured by IST Corporation) with a wavelength of 395 nm so that the cured film (sealing film) was 0.05%. The resulting cured film (sealing film) was peeled off from the glass substrate. A sample was cut to a length of 40 mm and a width of 5 mm. The dynamic viscoelasticity was measured under the following conditions: gap length 20 mm, strain 0.05%, frequency 10 Hz, temperature 0 to 180°C, and heating rate 5°C / min.

[0040] (Analysis) The storage modulus G' was measured at 25° C. The peak value (maximum value) of tan δ (= G'' / G': where G'' is the loss modulus) was used as an index of viscosity.

[0041] One way to achieve a loss factor (tan δ) peak value within the range of 0.3 to 1.0 is to adjust the type of monofunctional (meth)acrylate contained in the sealing composition. Another example of such a method is to adjust the content ratio of the monofunctional (meth)acrylate relative to the total amount of photopolymerizable monomers. Another example of a method to achieve a storage modulus within the range of 1.0 to 3.0 GPa is to adjust the type of monofunctional (meth)acrylate contained in the sealing composition and the content ratio of the monofunctional (meth)acrylate relative to the total amount of photopolymerizable monomers. Another possible method is to adjust the film thickness and curing rate of the sealing film. The film thickness is preferably within the range of 3 to 10 μm.

[0042] <Curing Rate> The sealing composition of the present invention is irradiated with ultraviolet light having a wavelength of 395 nm at a rate of 1.5 to 1.8 J / cm under a nitrogen gas atmosphere. ２ The curing rate of the sealing film formed when cured by irradiation is preferably 80% or more, more preferably 90% or more, with the upper limit being 100%.

[0043] The curing rate is measured by measuring the FT-IR of the sealing composition before curing and the sealing film (cured film) after light irradiation. Then, the peak of the C═C bond derived from the (meth)acryloyl group (810 cm) in the obtained spectrum is measured. －１ ) by the following formula: Cure rate (%)=(1-a / b)×100, where a is the peak value derived from the C═C bond of the sealing composition before curing, and b is the peak value derived from the C═C bond of the sealing film after curing.

[0044] Examples of means for achieving a cure rate of 80% or more include the use of a (meth)acrylate that is prone to radical reaction, and improving reaction efficiency by using a photopolymerization initiator or sensitizer that effectively absorbs 395 nm. Examples of (meth)acrylates that are prone to radical reaction include amine-containing (meth)acrylates and (meth)acrylates having an ethylene oxide group. Examples of (meth)acrylates that are prone to radical reaction include (meth)acrylates having a hydroxy group and (meth)acrylates with two or more (meth)acrylate functional groups. Furthermore, because acrylates are more reactive than methacrylates, compositions with a low methacrylate ratio can be used.

[0045] The composition of the encapsulating composition of the present invention will be described below: The encapsulating composition of the present invention contains a photopolymerizable monomer and a photopolymerization initiator.

[0046] <Photopolymerizable Monomer> The term "photopolymerizable monomer" refers to a photopolymerizable monomer (also referred to as a "photocurable monomer") that can undergo a polymerization (curing) reaction by absorbing light itself or a photopolymerization initiator to generate active ions or radicals. The photopolymerizable monomer may be a non-silicon monomer that does not contain silicon (Si), and may be, for example, a monomer consisting only of an element selected from C, H, O, N, or S, but is not limited thereto. The photopolymerizable monomer may be synthesized by a conventional synthesis method and used, or may be a commercially available product that is purchased and used.

[0047] The photopolymerizable monomer according to the present invention contains a (meth)acrylate. The (meth)acrylate preferably contains a monofunctional (meth)acrylate, and may further contain a polyfunctional (meth)acrylate. The (meth)acrylate preferably contains an aromatic hydrocarbon group, and particularly preferably contains a phenyl group.

[0048] <Monofunctional (meth)acrylate> When focusing on the longest continuous chain of carbon atoms in a molecule, the monofunctional (meth)acrylate includes a linear structure and a branched structure in which two or more carbon atoms are linked in a row. The chain skeleton may contain an atom selected from O, N, or S. For example, the chain skeleton may contain an ether bond, a sulfide bond, or the like. Such a monofunctional (meth)acrylate according to the present invention preferably has an alkylene skeleton or an alkylene oxide skeleton. In particular, it is preferable that the monofunctional (meth)acrylate has an alkylene skeleton or an ethylene oxide skeleton from the viewpoint of inkjet ejection properties and flex resistance. In the present invention, the term "alkylene oxide skeleton" refers to the structure (skeleton) of a divalent linking group (also referred to as an "alkyleneoxy group") in which an oxygen atom (—O—) is bonded to one end of an alkylene group. For example, the "ethylene oxide skeleton," which is an example of an "alkylene oxide skeleton," is a unit of two carbon chains and one oxygen atom. The ethylene oxide skeleton may have a structure of a monovalent ethylene oxide group (also referred to as an "epoxy ring group"), or may have a structure (skeleton) of a divalent linking group (also referred to as an "ethyleneoxy group") formed by ring-opening of the epoxy ring group.

[0049] Specific examples of the monofunctional (meth)acrylate include mono(meth)acrylates having a substituted or unsubstituted C2 to C20 alkylene group, an ethylene oxide group, or the like.

[0050] Examples of the monofunctional (meth)acrylate include unsaturated carboxylic acid esters including (meth)acrylic acid esters 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, decanyl (meth)acrylate, undecanyl (meth)acrylate, and dodecyl (meth)acrylate; unsaturated carboxylic acid aminoalkyl esters such as 2-aminoethyl (meth)acrylate and 2-dimethylaminoethyl (meth)acrylate; saturated or unsaturated carboxylic acid vinyl esters such as vinyl acetate; cyanide vinyl compounds such as (meth)acrylonitrile; unsaturated amide compounds such as (meth)acrylamide; or mixtures thereof, but are not limited thereto.

[0051] In addition to the above (meth)acrylates, epoxy (meth)acrylates can also be used.

[0052] The monofunctional (meth)acrylate according to the present invention may contain, as part of its linear or branched structure, at least one cyclic group selected from one phenyl group or phenylene group, a heterocyclic group, and a cycloalkyl group.

[0053] The heterocyclic group may be either an aromatic heterocyclic group or a non-aromatic heterocyclic group (for example, one having a heteroatom in the cycloalkyl skeleton).

[0054] Among the monofunctional (meth)acrylates, (meth)acrylates having a cycloalkyl group include mono(meth)acrylates having a substituted or unsubstituted C3 to C20 cycloalkyl group, and refer to monomers having a cyclopentane skeleton, a cyclohexane skeleton, a cycloheptane skeleton, a dicyclodecane structure, a tricyclodecane ring, an adamantane ring, or an isobornyl ring in their skeleton. Preferably, the cycloalkyl group contains a dicyclodecane group or a tricyclodecane group, which is preferable in terms of sealing performance.

[0055] Specific examples of the monofunctional (meth)acrylate include alicyclic (meth)acrylates such as isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and cyclohexyl (meth)acrylate, as well as 2-methyl-2-adamantyl (meth)acrylate, 2-ethyl-2-adamantyl (meth)acrylate, 3-hydroxy-1-adamantyl (meth)acrylate, and 1-adamantyl (meth)acrylate.

[0056] Among the monofunctional (meth)acrylates, the (meth)acrylate having a heterocyclic group refers to a monomer having a heterocyclic ring (heterocycle) in the skeleton.

[0057] Specific examples of the heterocyclic (heterocyclic) skeleton that can be used include a dioxane structure, a trioxane structure, an isocyanurate structure, etc. Specific examples of the (meth)acrylate having a heterocyclic group include, but are not limited to, tetrahydrofurfuryl (meth)acrylate, alkoxylated tetrahydrofurfuryl acrylate caprolactone-modified tetrahydrofurfuryl (meth)acrylate, morpholine (meth)acrylate, ε-caprolactone-modified tris(acryloxyethyl)isocyanurate (M-327), pentamethylpiperidinyl methacrylate (FA-711), tetramethylpiperidinyl methacrylate (FA-712HM), cyclic trimethylolpropane formal acrylate (SR531), and mixtures thereof.

[0058] Furthermore, among the monofunctional (meth)acrylates, examples of the (meth)acrylate having one phenyl group or one phenylene group include, but are not limited to, benzyl (meth)acrylate, ethoxy-modified cresol (meth)acrylate, propoxy-modified cresol (meth)acrylate, neopentyl glycol benzoate (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxy-polyethylene glycol (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-acryloyloxyethyl-phthalic acid, neopentyl glycol-acrylic acid-benzoic acid ester, nonylphenol ethylene oxide (meth)acrylate, nonylphenol propylene oxide acrylate, and mixtures thereof.

[0059] Among the monofunctional (meth)acrylates, those containing a dioxane glycol group as the heterocyclic (heterocyclic) skeleton and a phenoxyethyl group, a phenoxydiethylene glycol group, or a nonylphenolethylene oxide group as one phenyl group are preferred, which stabilize the compound due to the planar molecular structure and provide excellent heat resistance, sealing performance, and adhesion.

[0060] In the present invention, preferred examples of the monofunctional (meth)acrylate include orthophenylphenoxyethyl acrylate (compound a-1 below), nonylphenol EO-modified acrylate (compound a-2 below), phenoxydiethylene glycol acrylate (compound a-3 below), stearyl acrylate (compound a-4 below), isobornyl acrylate (compound a-5 below), and 4-phenylbenzyl acrylate (compound a-6 below).

[0061] The monofunctional (meth)acrylate according to the present invention preferably has an aromatic hydrocarbon group, and particularly preferably has a phenyl group. Examples of the monofunctional (meth)acrylate having a phenyl group include orthophenylphenoxyethyl acrylate (compound a-1), nonylphenol EO-modified acrylate (compound a-2), phenoxydiethylene glycol acrylate (compound a-3), and 4-phenylbenzyl acrylate (compound a-6).

[0062]

[0063] The content of the monofunctional (meth)acrylate according to the present invention is preferably 41% by mass or more relative to the total amount of photopolymerizable monomers, and more preferably within the range of 50 to 75% by mass.

[0064] <Polyfunctional (meth)acrylate> The polyfunctional (meth)acrylate according to the present invention includes a straight-chain structure and a branched structure in which two or more carbon atoms are linked in a row, when focusing on the longest continuous chain of carbon atoms in the molecule. The chain skeleton may contain an atom selected from O, N, and S. For example, the chain skeleton may contain an ether bond, a sulfide bond, or the like.

[0065] The polyfunctional (meth)acrylate according to the present invention may have an alkylene skeleton or an alkylene oxide skeleton, similar to the monofunctional (meth)acrylate. Also, the polyfunctional (meth)acrylate according to the present invention may contain, as a part of a linear or branched structure, at least one cyclic group selected from one phenyl group or phenylene group, a heterocyclic group, and a cycloalkyl group, similar to the monofunctional (meth)acrylate.

[0066] Specific examples of polyfunctional (meth)acrylates include di(meth)acrylates, tri(meth)acrylates, and tetra(meth)acrylates having a substituted or unsubstituted C2 to C20 alkylene group, an ethylene oxide group, or the like. In particular, from the viewpoints of inkjet ejection properties over time and flex resistance, it is preferable to select from ethylene glycol di(meth)acrylates having a structure represented by the following general formula (1) or di(meth)acrylates having 6 to 10 carbon atoms in the alkylene skeleton. Among the ethylene glycol di(meth)acrylates having a structure represented by the following general formula (1), triethylene glycol di(meth)acrylate is particularly preferred.

[0067]

[0068] Examples of polyfunctional (meth)acrylates include ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, pentaethylene glycol di(meth)acrylate, hexaethylene glycol di(meth)acrylate, polytetraethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,10-decanediol diacrylate, 1,12-dodecanediol dimethacrylate, octanediol di(meth)acrylate, nonanediol di(meth)acrylate, decanediol di(meth)acrylate, undecanediol di(meth)acrylate, and dodecanediol. di(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, hexyl di(meth)acrylate, decyl di(meth)acrylate, dodecyl dimethacrylate, ethoxylated glycerin tri(meth)acrylate, stearyl (meth)acrylate, 2-hydroxy-1,3-dimethacryloxypropane, polyethylene glycol #600 di(meth)acrylate, or mixtures thereof, but are not limited thereto.

[0069] Examples of the polyfunctional (meth)acrylate according to the present invention include triethylene glycol diacrylate (compound a-7 below), triethylene glycol dimethacrylate (compound a-8 below), decyl diacrylate (compound a-9 below), and tricyclodecane dimethanol diacrylate (compound a-10 below).

[0070]

[0071] The content of the polyfunctional (meth)acrylate according to the present invention is preferably within a range of 25 to 59% by mass relative to the total amount of photopolymerizable monomers, in order to obtain an appropriate loss coefficient (tan δ) and storage modulus (G'). The content is more preferably within a range of 25 to 40% by mass.

[0072] <Photopolymerization initiator> The photopolymerization initiator is not particularly limited as long as it is a common photopolymerization initiator that can cause a photocuring reaction. Examples of the photopolymerization initiator include triazine-based, acetophenone-based, benzophenone-based, thioxanthone-based, benzoin-based, phosphorus-based, oxime-based, and mixtures thereof.

[0073] Examples of triazine initiators include 2,4,6-trichloro-s-triazine, 2-phenyl-4,6-bis(trichloromethyl)-s-triazine, 2-(3',4'-dimethoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4'-methoxynaphthyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(p-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, and 2-(p-tolyl)-4,6-bis(trichloromethyl)-s-triazine. , 2-biphenyl-4,6-bis(trichloromethyl)-s-triazine, bis(trichloromethyl)-6-styryl-s-triazine, 2-(naphth-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methoxynaphth-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2,4-trichloromethyl(piperonyl)-6-triazine, 2,4-(trichloromethyl(4'-methoxystyryl)-6-triazine, or a mixture thereof.

[0074] The acetophenone 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-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, and mixtures thereof.

[0075] The benzophenone initiator may be benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, or acrylated benzophenone. The benzophenone initiator may also be 4,4'-bis(dimethylamino)benzophenone, 4,4'-dichlorobenzophenone, or 3,3'-dimethyl-2-methoxybenzophenone. Furthermore, the benzophenone initiator may be a mixture of the above.

[0076] The thioxanthone initiator may be thioxanthone, 2-methylthioxanthone, isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, 2-chlorothioxanthone, or a mixture of the above.

[0077] The benzoin initiator may be benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzil dimethyl ketal, or mixtures thereof.

[0078] The phosphorus-based initiator may be bisbenzoylphenylphosphine oxide, benzoyldiphenylphosphine oxide, or a mixture thereof. The oxime-based initiator may be 2-(o-benzoyloxime)-1-[4-(phenylthio)phenyl]-1,2-octanedione. The oxime-based initiator may also be 1-(o-acetyloxime)-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone. Furthermore, the oxime-based initiator may be a mixture of the above. A preferred commercially available photopolymerization initiator is IRGACURE (registered trademark) 819: bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (manufactured by BASF).

[0079] The photopolymerization initiator is preferably contained in the encapsulating composition of the present invention in a range of approximately 0.1 to 20 parts by mass, relative to 100 parts by mass of the total of the photopolymerizable monomer and the photopolymerization initiator. By ensuring this range, photopolymerization occurs sufficiently during exposure, and a decrease in transmittance due to remaining unreacted initiator after photopolymerization can be prevented. Specifically, the 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. The photopolymerization initiator is preferably contained in the encapsulating composition of the present invention in a range of 0.1 to 10% by mass, more preferably in a range of 0.1 to 5% by mass, based on the solids content. By ensuring this range, photopolymerization occurs sufficiently, and a decrease in transmittance due to remaining unreacted initiator can be prevented.

[0080] Instead of the photopolymerization initiator, a photoacid generator or photopolymerization initiator such as a carbazole type, a diketone, a sulfonium type, an iodonium type, a diazo type, or a biimidazole type may be used.

[0081] <Other Additives> The encapsulating composition of the present invention may further contain other components, including antioxidants, thermal stabilizers, photosensitizers, dispersants, thermal crosslinkers, surfactants, and polymerization inhibitors, as long as the effects of the present invention are achieved. These components may be contained alone or in combination with one another in the encapsulating composition of the present invention. The antioxidant can improve the thermal stability of the encapsulating layer. The antioxidant may include, but is not limited to, one or more antioxidants selected from the group consisting of phenols, quinones, amines, and phosphites. Examples of antioxidants include tetrakis[methylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate)]methane and tris(2,4-di-tert-butylphenyl)phosphite.

[0082] The antioxidant is preferably contained in the sealing composition in a range of 0.01 to 3 parts by mass relative to 100 parts by mass of the total of the photopolymerizable monomer and the photopolymerization initiator. The antioxidant is more preferably contained in the sealing composition in a range of 0.01 to 1 part by mass. By containing the antioxidant in this range, excellent thermal stability can be exhibited.

[0083] The heat stabilizer is contained in the sealing composition and serves to suppress a change in viscosity of the sealing composition at room temperature, and any conventional heat stabilizer can be used without limitation. For example, a sterically hindered phenolic heat stabilizer may be used as the heat stabilizer. Specific examples of the heat stabilizer 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'-methano-bi(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 ...'-di-tert-butyl-4-hydroxyphenyl)propionate, 2,6'-di-tert-butyl-4-hydroxyphenyl)propionate, 2,6'-di-tert-butyl-4-hydroxyphenyl)propionate, 2,6'-di-tert-butyl-4-hydroxyphenyl)propionate, 2,6'-di-tert-butyl-4-hydroxyphenyl)propionate, 2,6'-di- The hydroxyphenyl)-N,N'-hexamethylene-dipropionamide, pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), stearyl-3,5-di-tert-butyl-4-hydroxyphenylpropionate, pentaerythritol tetrakis-1,3,5-tris(2,6-di-methyl-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-butylhydroxyphenylpropionate), but is not limited thereto.

[0084] The heat stabilizer is preferably contained in the sealing composition in an amount of 2000 ppm or less based on the total of the photocurable monomer and the photopolymerization initiator, based on the solid content. The heat stabilizer is preferably contained in a range of 0.01 to 2000 ppm, more preferably in a range of 100 to 1000 ppm. By setting the heat stabilizer within this range, the storage stability and processability of the sealing composition in a liquid state can be further improved.

[0085] The photosensitizer has the function of transferring absorbed light energy to the photopolymerization initiator, and is therefore a compound that can impart the original photopolymerization initiator function to the photopolymerization initiator used even if the photopolymerization initiator does not absorb light corresponding to the light from the light source.

[0086] Examples of the photosensitizer include 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, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, 2,4,6-trimethylbenzophenone, and 4-benzoyl-N,N-dimethylbenzophenone. benzophenone derivatives such as 4-benzoylbenzyl)trimethylammonium chloride, and 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, and 2-(3-dimethylamino-2-hydroxy)-3,4-dimethyl-9Hthioxanthone-9-one mesochloride. Among these, anthracene derivatives, benzoin derivatives, benzophenone derivatives, anthraquinone derivatives, and thioxanthone derivatives are preferably used as the photosensitizer.

[0087] The polymerization inhibitor preferably contains any one of an N-oxyl polymerization inhibitor, a phenolic polymerization inhibitor containing an o-t-butyl group, or a polymerization inhibitor having two or more aromatic rings. In particular, it is preferable to use an N-oxyl polymerization inhibitor. Commercially available N-oxyl polymerization inhibitors include IRGASTAB (registered trademark) UV10 (manufactured by BASF).

[0088] <UV Curing> The sealing composition of the present invention is cured by irradiating ultraviolet light at a rate of 10 to 500 mW / cm ２ It is preferable to cure the composition by irradiating the composition for 1 to 100 seconds within the range of 1 to 100 seconds, but this is not a limitation. As the ultraviolet light, it is preferable to use an LED with a wavelength of 395 nm in order to prevent deterioration of the electronic device.

[0089] <Physical Properties> The viscosity of the sealing composition of the present invention is preferably within the range of 3 to 30 mPa·s. Having a viscosity within this range further improves the ejectability from an inkjet head. The surface tension of the sealing composition of the present invention is preferably 15 mN / m or more and less than 45 mN / m, from the viewpoint of further improving the ejectability from an inkjet head. The viscosity of the sealing composition of the present invention can be determined, for example, by measuring the temperature change of the dynamic viscoelasticity of the sealing composition using various rheometers.

[0090] In the present invention, these viscosities are values ​​obtained by the following method: The sealing composition of the present invention is set in a stress-controlled rheometer Physica MCR300 (cone plate diameter: 75 mm, cone angle: 1.0°) manufactured by Anton Paar. Next, the sealing composition is heated to 100°C and cooled to 20°C under conditions of a temperature decrease rate of 0.1°C / s, a strain of 5%, and an angular frequency of 10 radian / s, to obtain a temperature change curve of dynamic viscoelasticity.

[0091] The sealing composition of the present invention may contain pigment particles. When the sealing composition of the present invention contains a pigment, the average particle size of the pigment particles 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. When the sealing composition contains the pigment particles, the ejection properties from an inkjet head can be further improved.

[0092] The average particle size of pigment particles in the present invention refers to a value determined by dynamic light scattering using a Datasizer Nano ZSP (manufactured by Malvern). Since the concentration of the sealing composition containing the colorant is high and light does not pass through this measuring device, the sealing composition is diluted 200 times before measurement. The measurement temperature is room temperature (25°C).

[0093] The sealing composition of the present invention preferably has an Ohnesorge number (Oh) expressed by the following formula 1, which is calculated by the density ρ, the surface tension σ of the sealing composition, the viscosity μ of the sealing composition, and the nozzle diameter D0, in the range of 0.1 to 1. This results in excellent inkjet ejection properties and excellent stabilization of ink droplets during flight.

[0094] It is preferable to prepare the encapsulating composition of the present invention and provide a cured polymer having a Tg (glass transition temperature) 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 viewpoint of ensuring stability in the formation process of electronic devices, driving temperatures, and reliability tests.

[0095] [Electronic Device Sealing Film Forming Method] The electronic device sealing film forming method of the present invention is a method for forming a sealing film using the electronic device sealing composition of the present invention, and includes the steps of forming a first sealing layer on an electronic device by a vapor phase method and forming a second sealing layer by applying the electronic device sealing composition on the first sealing layer. Furthermore, it is preferable to include the step of forming a third sealing layer on the second sealing layer by a vapor phase method, in order to further improve the sealing performance of the electronic device.

[0096] <First Encapsulating Layer Forming Process> In the first encapsulating layer forming process, a first encapsulating layer is formed on an electronic device by a vapor-phase process. Examples of vapor-phase processes include sputtering, vapor deposition, thermal CVD, and catalytic chemical vapor deposition (Cat-CVD). Examples of the vapor-phase process include chemical vapor deposition processes such as capacitively coupled plasma CVD (CCP-CVD), photo-assisted CVD, plasma-enhanced CVD (PECVD), epitaxial growth, and atomic layer deposition (ALD). Among these, ALD and CVD processes are preferred. Examples of the sputtering process include reactive sputtering processes such as magnetron cathode sputtering, planar magnetron sputtering, bipolar AC planar magnetron sputtering, and bipolar AC rotating magnetron sputtering. Examples of the vapor deposition process include resistance heating evaporation, electron beam evaporation, ion beam evaporation, and plasma-assisted evaporation.

[0097] The first sealing layer contains silicon nitride (SiNx), silicon oxynitride (SiNOx), or silicon oxide (SiOx). In a specific example of forming the first sealing layer, the pressure inside the chamber is reduced, and silane (SiH ４ ), ammonia (NH ３ ), hydrogen (H ２ The thickness of the first sealing layer is preferably in the range of 10 to 1000 nm, and more preferably in the range of 100 to 500 nm, for example.

[0098] <Second sealing layer forming step> The second sealing layer forming step forms a second sealing layer by applying the sealing composition of the present invention onto the first sealing layer. Specifically, the second sealing layer forming step includes a step of applying the sealing composition onto the first sealing layer (application step) and curing the resulting coating film by irradiating it with ultraviolet light under a nitrogen gas atmosphere. It may also include a step of modifying the coating by irradiating it with vacuum ultraviolet light.

[0099] (Coating step) Any appropriate method can be adopted as a method for coating the sealing composition. Examples of the coating method include spin coating, roll coating, flow coating, inkjet coating, spray coating, printing, dip coating, casting, bar coating, and gravure printing. Among these, the inkjet method is preferred because it allows fine patterning, which is required for sealing electronic devices such as organic EL elements, to be performed on demand.

[0100] As the inkjet method, a known method can be used. Inkjet methods are roughly divided into two types: a drop-on-demand method and a continuous method, and either method can be used.

[0101] Drop-on-demand methods include electromechanical conversion methods, electrothermal conversion methods, electrostatic attraction methods, and discharge methods. Examples of electromechanical conversion methods include single-cavity types, double-cavity types, bender types, piston types, shear mode types, and shared-wall types. Examples of electrothermal conversion methods include thermal inkjet types and bubble jet (registered trademark) types. Examples of electrostatic attraction methods include electric field control types and slit jet types. Examples of discharge methods include spark jet types. From the standpoint of inkjet head cost and productivity, it is preferable to use an electromechanical conversion or electrothermal conversion head. Note that a method of dropping droplets (e.g., a coating liquid) using an inkjet method is sometimes referred to as an "inkjet method." The sealing composition is preferably applied under a nitrogen gas atmosphere.

[0102] (Curing Treatment Step) In the curing treatment step, after the coating step, the obtained coating film is irradiated with ultraviolet light in a nitrogen gas atmosphere. The illuminance of the ultraviolet light on the coating film surface is 10 to 500 mW / cm. ２ It is preferable to cure the composition by irradiating the composition for 1 to 100 seconds within the range of 1 to 100 seconds, but this is not a limitation. As the ultraviolet light, it is preferable to use an LED with a wavelength of 395 nm in order to prevent deterioration of the electronic device.

[0103] (Modification Treatment Step) In the second sealing layer forming step, a modification treatment may be performed. In the modification treatment step, after the coating step, the obtained coating film is modified by irradiating it with vacuum ultraviolet light in a nitrogen gas atmosphere. The modification treatment refers to a conversion reaction of polysilazane to silicon oxide or silicon oxynitride. The modification treatment is also performed in a nitrogen gas atmosphere or under reduced pressure, such as in a glove box.

[0104] The modification treatment in the present invention can be performed by any known method based on the conversion reaction of polysilazane. In the present invention, conversion reactions using plasma, ozone, or ultraviolet rays, which can perform the conversion reaction at low temperatures, are preferred. Conventionally known methods for plasma and ozone can be used.

[0105] In the present invention, the second sealing layer according to the present invention is preferably formed by providing the coating film and then modifying it by irradiating it with vacuum ultraviolet light (also referred to as VUV) having a wavelength of 200 nm or less. The thickness of the second sealing layer is preferably in the range of 0.5 to 10 μm, more preferably in the range of 3 to 10 μm. Although the entire second sealing layer may be modified, the thickness of the modified layer after the modification treatment is preferably in the range of 1 to 50 nm, more preferably in the range of 1 to 30 nm.

[0106] In the step of modifying the coating film by irradiating it with vacuum ultraviolet rays, the illuminance of the vacuum ultraviolet rays on the surface of the coating film is 30 to 200 mW / cm ２ The irradiance of the vacuum ultraviolet light is preferably in the range of 50 to 160 mW / cm. ２ It is more preferable that the irradiance of the vacuum ultraviolet light is within the range of 30 mW / cm. ２ By setting the irradiance of the vacuum ultraviolet light to 200 mW / cm or more, the modification efficiency can be sufficiently improved. ２ In the following, the incidence of damage to the coating film can be significantly reduced, and damage to the substrate can also be reduced.

[0107] The irradiation energy of vacuum ultraviolet rays on the coating film surface is 1 to 10 J / cm ２From the viewpoint of barrier properties and moist heat resistance for maintaining the desiccant function, the amount of irradiation energy is preferably in the range of 3 to 7 J / cm. ２ It is more preferable that the range is within the range of

[0108] A rare gas excimer lamp is preferably used as the light source for the vacuum ultraviolet light. Vacuum ultraviolet light is absorbed by oxygen, which tends to reduce the efficiency of the vacuum ultraviolet light irradiation process. Therefore, it is preferable to perform the vacuum ultraviolet light irradiation in a state where the oxygen concentration is as low as possible. That is, the oxygen concentration during vacuum ultraviolet light irradiation is preferably in the range of 10 to 10,000 ppm. The oxygen concentration is more preferably in the range of 50 to 5,000 ppm, and even more preferably in the range of 80 to 4,500 ppm. The oxygen concentration is most preferably in the range of 100 to 1,000 ppm.

[0109] The modification treatment can also be carried out in combination with a heat treatment. The heating conditions are preferably a temperature in the range of 50 to 300°C, more preferably 60 to 150°C, and a time of preferably 1 second to 60 minutes, more preferably 10 seconds to 10 minutes. By combining the heat treatment, the dehydration condensation reaction during modification is promoted, and the modified product can be formed more efficiently.

[0110] Examples of the heat treatment include a method in which the substrate is brought into contact with a heating element such as a heat block to heat the coating film by thermal conduction, and a method in which the atmosphere is heated by an external heater such as a resistance wire. Other examples of the heat treatment include a method using light in the infrared region such as an IR heater, but these are not particularly limited. Furthermore, any method that can maintain the smoothness of the coating film containing a silicon compound may be appropriately selected.

[0111] <Third sealing layer forming step> In the third sealing layer forming step, a third sealing layer is formed on the second sealing layer by a vapor phase method. Examples of the vapor phase method include sputtering, evaporation, thermal CVD, and catalytic chemical vapor deposition (Cat-CVD), similar to the vapor phase methods used in the first sealing layer forming step. Examples of the vapor phase method include chemical vapor deposition methods such as capacitively coupled plasma CVD (CCP-CVD), photo-assisted CVD, plasma CVD (PE-CVD), epitaxial growth, and atomic layer deposition (ALD). Among these, ALD and CVD are preferred. Examples of the sputtering method include reactive sputtering methods such as magnetron cathode sputtering, planar magnetron sputtering, bipolar AC planar magnetron sputtering, and bipolar AC rotating magnetron sputtering. The vapor deposition methods include, for example, resistance heating vapor deposition, electron beam vapor deposition, ion beam vapor deposition, plasma assisted vapor deposition, and the like.

[0112] The third sealing layer contains silicon nitride (SiNx), silicon oxynitride (SiNOx), or silicon oxide (SiOx). In a specific example of forming the third sealing layer, the pressure in the chamber is reduced, and silane (SiH ４ ), ammonia (NH ３ ), hydrogen (H ２ ) is heated and supplied into a chamber to form the third sealing layer. The thickness of the third sealing layer is preferably within a range of 10 to 1000 nm, and more preferably within a range of 100 to 500 nm. As described above, after forming the sealing film, a conductive film for a touch sensor may be further formed.

[0113] The conductive film may be formed of a metal compound film such as ITO (indium tin oxide) or IZO (indium zinc oxide). The conductive film may also be formed of a highly flexible graphene film or a metal nanowire film (e.g., a film containing silver nanowires or copper nanowires). The conductive film may also be formed of a metal nanoparticle film (e.g., a film containing silver nanoparticles or copper nanoparticles). The conductive film may also be formed of a multi-metal laminate film such as an Al film / Ti film / Al film.

[0114] [Electronic Device Sealing Film] The electronic device sealing film of the present invention is an electronic device sealing film for sealing an electronic device, and 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.

[0115] The electronic device sealing film of the present invention is formed by the method for forming an electronic device sealing film. That is, a second sealing layer is formed using the electronic device sealing composition of the present invention. 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.

[0116] <First sealing layer> The first sealing layer is a layer formed on an electronic device by the vapor phase method described above. Specifically, the first sealing layer contains silicon nitride, silicon oxide (silicon monoxide, silicon dioxide, etc.), or silicon oxynitride.

[0117] <Second sealing layer> The second sealing layer is provided adjacent to the first sealing layer and is formed by applying the sealing composition onto the first sealing layer. Therefore, the second sealing layer contains a polymer composed of the photopolymerizable monomer. The photopolymerizable monomer preferably contains a monofunctional (meth)acrylate and a polyfunctional (meth)acrylate. The presence of the polymer in the second sealing layer can be detected by various conventional analytical methods, such as chromatography, infrared spectroscopy, ultraviolet-visible spectroscopy, nuclear magnetic resonance analysis, X-ray diffraction, mass spectroscopy, and X-ray photoelectron spectroscopy. The content of the polymer in the second sealing layer is preferably within a range of 85 to 100% by mass, and more preferably within a range of 90 to 95% by mass.

[0118] The third sealing layer is a layer formed adjacent to the second sealing layer by the vapor deposition method described above. Specifically, like the first sealing layer, the third sealing layer contains silicon nitride, silicon oxide (silicon monoxide, silicon dioxide, etc.), or silicon oxynitride.

[0119] [Electronic Device] In the method for forming an electronic device sealing film and the electronic device sealing film of the present invention, examples of the electronic device to be sealed include organic EL elements, LED elements, and liquid crystal display elements (LCDs). Examples of the electronic device include thin film transistors, touch panels, electronic paper, and solar cells (PV). From the viewpoint of more efficiently achieving the effects of the present invention, the electronic device is preferably an organic EL element, a solar cell, or an LED element, and particularly preferably an organic EL element.

[0120] <Organic EL element> The organic EL element employed as the electronic device according to the present invention may be a bottom-emission type, i.e., one in which light is extracted from the transparent substrate side. Specifically, the bottom-emission type is configured by laminating a transparent electrode serving as a cathode, a light-emitting functional layer, and a counter electrode serving as an anode in this order on a transparent substrate. Alternatively, the organic EL element according to the present invention may be a top-emission type, i.e., one in which light is extracted from the transparent electrode side serving as the cathode, opposite the substrate.

[0121] Specifically, the top-emission type has a configuration in which a counter electrode serving as an anode is provided on the substrate side, and a light-emitting functional layer and a transparent electrode serving as a cathode are laminated on the surface of this in this order. Representative examples of the configuration of organic EL elements are shown below. (i) anode / hole injection transport layer / light-emitting layer / electron injection transport layer / cathode (ii) anode / hole injection transport layer / light-emitting layer / hole blocking layer / electron injection transport layer / cathode (iii) anode / hole injection transport layer / electron blocking layer / light-emitting layer / hole blocking layer / electron injection transport layer / cathode (iv) anode / hole injection layer / hole transport layer / light-emitting layer / electron transport layer / electron injection layer / cathode (v) anode / hole injection layer / hole transport layer / light-emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode (vi) anode / hole injection layer / hole transport layer / electron blocking layer / light-emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode

[0122] Furthermore, the organic EL element may have a non-light-emitting intermediate layer. The intermediate layer may be a charge generating layer or may have a multi-photon unit configuration. Overviews of organic EL elements applicable to the present invention are described in, for example, JP-A Nos. 2013-157634, 2013-168552, 2013-177361, 2013-187211, 2013-191644, 2013-191804, 2013-225678, 2013-235994, and 2013-243234. Examples of the configurations described in JP-A-2013-243236, JP-A-2013-242366, JP-A-2013-243371, JP-A-2013-245179, JP-A-2014-003249, JP-A-2014-003299, JP-A-2014-013910, JP-A-2014-017493, JP-A-2014-017494, and the like can be given.

[0123] <Substrate> Specifically, the substrate that can be used in the organic EL element is preferably glass or a resin film, and when flexibility is required, a resin film is preferable. Hereinafter, the substrate will also be referred to as a supporting substrate, a base, a substrate, a support, etc.

[0124] The substrate may be transparent or opaque. In the case of a so-called bottom-emission type in which light is extracted from the substrate side, the substrate is preferably transparent. Preferred resins include substrates containing thermoplastic resins such as polyester resins, methacrylic resins, methacrylic acid-maleic acid copolymers, polystyrene resins, transparent fluororesins, polyimides, fluorinated polyimide resins, polyamide resins, polyamideimide resins, polyetherimide resins, cellulose acylate resins, polyurethane resins, polyether ether ketone resins, polycarbonate resins, alicyclic polyolefin resins, polyarylate resins, polyethersulfone resins, polysulfone resins, cycloolefin copolymers, fluorene ring-modified polycarbonate resins, alicyclic polycarbonate resins, fluorene ring-modified polyester resins, and acryloyl compounds. These resins may be used alone or in combination of two or more.

[0125] The substrate is preferably made of a heat-resistant material. Specifically, a substrate having a linear expansion coefficient of 15 ppm / K to 100 ppm / K and a glass transition temperature (Tg) of 100°C to 300°C is used. This substrate meets the requirements for electronic component applications and laminate films for displays. That is, when the sealing film of the present invention is used for these applications, the substrate may be exposed to processes at 150°C or higher. If the linear expansion coefficient of the substrate exceeds 100 ppm / K, the substrate dimensions will not be stable when subjected to processes at such temperatures, and thermal expansion and contraction may cause problems such as deterioration of barrier properties or inability to withstand thermal processes. If the linear expansion coefficient is less than 15 ppm / K, the film may crack like glass, resulting in poor flexibility.

[0126] The Tg and linear expansion coefficient of the substrate can be adjusted by additives, etc. More preferred specific examples of thermoplastic resins that can be used as the substrate include polyethylene terephthalate (PET: 70°C), polyethylene naphthalate (PEN: 120°C), polycarbonate (PC: 140°C), alicyclic polyolefins (e.g., Zeonor (registered trademark) 1600 manufactured by Nippon Zeon Co., Ltd.: 160°C), polyarylate (PAr: 210°C), polyethersulfone (PES: 220°C), polysulfone (PSF: 190°C), cycloolefin copolymers (COC: JP 2004-100644 A), and the like. 1-150584: 162°C), polyimide (for example, Neoprim (registered trademark) manufactured by Mitsubishi Gas Chemical Company, Inc.: 260°C), fluorene ring-modified polycarbonate (BCF-PC: compound described in JP-A-2000-227603: 225°C), alicyclic modified polycarbonate (IP-PC: compound described in JP-A-2000-227603: 205°C), acryloyl compound (compound described in JP-A-2002-80616: 300°C or higher) and the like (the temperature in parentheses indicates Tg).

[0127] Since the electronic device according to the present invention is an electronic device such as an organic EL element, the substrate is preferably transparent. That is, the light transmittance is usually 80% or more, preferably 85% or more, and more preferably 90% or more. The light transmittance can be calculated by measuring the total light transmittance and the amount of scattered light using an integrating sphere light transmittance measuring device according to the method described in JIS K7105:1981, and subtracting the diffuse transmittance from the total light transmittance.

[0128] The substrates described above may be unstretched films or stretched films. The substrates can be produced by conventional methods. The methods for producing these substrates may be appropriately selected from those described in paragraphs "0051" to "0055" of International Publication No. 2013 / 002026.

[0129] The surface of the substrate may be subjected to various known treatments for improving adhesion, such as corona discharge treatment, flame treatment, oxidation treatment, or plasma treatment, or a combination of these treatments may be performed as needed. The substrate may also be subjected to an adhesion-facilitating treatment. The substrate may have a single layer or a laminated structure of two or more layers. When the substrate has a laminated structure of two or more layers, the substrates may be the same type or different types.

[0130] The thickness of the substrate according to the present invention (total thickness when it has a laminated structure of two or more layers) is preferably 10 to 200 μm, more preferably 20 to 150 μm. Furthermore, in the case of a film substrate, it is preferable that the film substrate has a gas barrier layer. The gas barrier layer for the film substrate may be formed by forming an inorganic or organic coating, or a hybrid coating of both, on the surface of the film substrate. Furthermore, the gas barrier layer has a water vapor permeability (at 25±0.5°C and a relative humidity of (90±2)% RH) of 0.01 g / m ２ The gas barrier layer preferably has an oxygen permeability of 1×10 or less. －３ mL / m ２ ・24h・atm or less, water vapor permeability is 1 x 10 －３ g / m ２ The film preferably has high gas barrier properties lasting for 24 hours or less. The oxygen permeability is a value measured by a method in accordance with JIS K 7126-1987.

[0131] The material for forming the gas barrier layer may be any material that has the function of preventing the penetration of substances that cause deterioration of the element, such as moisture and oxygen, etc. Examples of such materials that can 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, or silicon oxycarbide, the layer is preferably formed from an inorganic material by a sputtering method (e.g., magnetron cathode sputtering, planar magnetron sputtering, bipolar AC planar magnetron sputtering, bipolar AC rotary magnetron sputtering, etc.), a vapor deposition method (e.g., resistance heating vapor deposition, electron beam vapor deposition, ion beam vapor deposition, plasma-assisted vapor deposition, etc.), a thermal CVD method, catalytic chemical vapor deposition (Cat-CVD), capacitively coupled plasma CVD (CCP-CVD), photo-CVD, plasma CVD (PE-CVD), epitaxial growth, atomic layer deposition (ALD), reactive sputtering, or other chemical vapor deposition method.

[0132] The inorganic gas barrier layer can be formed by applying a coating liquid containing an inorganic precursor such as polysilazane or tetraethyl orthosilicate (TEOS) onto a support, followed by a modification treatment such as irradiation with vacuum ultraviolet light. The inorganic gas barrier layer can also be formed by film metallization techniques such as metal plating on a resin substrate or bonding a metal foil to a resin substrate. The inorganic gas barrier layer may also contain an organic layer containing an organic polymer. That is, the inorganic gas barrier layer may be a laminate of an inorganic layer containing an inorganic material and an organic layer.

[0133] The organic layer can be formed by first applying, for example, an organic monomer or organic oligomer to a resin substrate to form a layer. Subsequently, the layer can be polymerized and optionally crosslinked using, for example, an electron beam device, a UV light source, a discharge device, or other suitable device. Alternatively, the organic layer can be formed by, for example, flash evaporation and vapor deposition of a radiation-crosslinkable organic monomer or organic oligomer. The organic monomer or organic oligomer can then be polymerized. The coating efficiency can be improved by cooling the resin substrate. Examples of methods for applying the organic monomer or organic oligomer include roll coating (e.g., gravure roll coating) and spray coating (e.g., electrostatic spray coating). Examples of laminates of inorganic and organic layers include the laminates described in International Publication Nos. 2012 / 003198 and 2011 / 013341.

[0134] In the case of a laminate of an inorganic layer and an organic layer, the thicknesses of the layers may be the same or different. The thickness of the inorganic layer is preferably in the range of 3 to 1,000 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.

[0135] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these. In the following examples, unless otherwise specified, operations were carried out at room temperature (25°C). Furthermore, unless otherwise specified, "%" and "parts" mean "% by mass" and "parts by mass", respectively.

[0136] [Preparation of Sealing Compositions 1 to 16] Monofunctional (meth)acrylates and diacrylates were weighed out under a nitrogen gas atmosphere so as to have the types and parts by mass shown in Table I. Furthermore, the following photopolymerization initiators, sensitizers, and polymerization inhibitors were placed in a brown bottle and stirred on a hot plate at 65°C for 3 hours to obtain sealing compositions 1 to 16.

[0137] <Photopolymerization initiator> BAPO (bisacylphosphine oxide): IRGACURE (registered trademark) 819: bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (manufactured by BASF) 5 parts by mass

[0138] <Sensitizer> 2-ITX: 2-isopropylthioxanthone (manufactured by Lambson) 1 part by mass

[0139] <Polymerization inhibitor> IRGASTAB (registered trademark) UV10: [1,10-dioxodecane-1,10-diylbis(oxy)bis(2,2,6,6-tetramethyl-4,1-piperidinediyl)bisoxy]radical (manufactured by BASF) 0.1 part by mass

[0140]

[0141] <Monofunctional (meth)acrylates> a-1: orthophenylphenoxyethyl acrylate (A-LEN10, manufactured by Shin-Nakamura Chemical Co., Ltd.) a-2: nonylphenol EO-modified acrylate (M-111, manufactured by Toagosei Co., Ltd.) a-3: phenoxydiethylene glycol acrylate (AMP-20GY, manufactured by Shin-Nakamura Chemical Co., Ltd.) a-4: stearyl acrylate (A-S, manufactured by Shin-Nakamura Chemical Co., Ltd.) a-5: isobornyl acrylate (IBA, manufactured by Kyoeisha Chemical Co., Ltd.) a-6: 4-phenylbenzyl acrylate (NK ester A-BPML, manufactured by Shin-Nakamura Chemical Co., Ltd.)

[0142] <Diacrylates> a-7: Triethylene glycol diacrylate (SR272, manufactured by Arkema) a-8: Triethylene glycol dimethacrylate (SR205, manufactured by Arkema) a-9: Decyl diacrylate (ADODN, manufactured by Shin-Nakamura Chemical Co., Ltd.) a-10: Tricyclodecane dimethanol diacrylate (A-DCP, manufactured by Shin-Nakamura Chemical Co., Ltd.)

[0143]

[0144] [Loss Factor (tan δ) Peak Value and Storage Modulus (G')] RSA3 manufactured by TA Instruments was used as a dynamic viscoelasticity measuring device. A tensile tool was used to mount the sample. As a sample, a coating film of the sealing composition having a thickness of 10 μm or 20 μm as shown in Table II below was prepared on a glass substrate having dimensions of 50 mm × 50 mm under a nitrogen atmosphere. This coating film was then irradiated with 300 mW / cm under a nitrogen atmosphere. ２ The cumulative light intensity under these conditions is 1.5 J / cm ２ The coating film was cured by irradiating it with ultraviolet light having a wavelength of 395 nm (MZ 240 mm 395 nm UVLED manufactured by IST Corporation) so that the cumulative light amount was 1.0 J / cm . The resulting cured film (sealing film) was peeled off from the glass substrate. Note that for sealing films 7-1 and 7-2, the cumulative light amount was 1.0 J / cm . ２ , 1.8 J / cm ２ The sample was cut to a length of 40 mm and a width of 5 mm. The dynamic viscoelasticity was measured under the following conditions: gap length 20 mm, strain 0.05%, frequency 10 Hz, temperature 0 to 180°C, and heating rate 5°C / min.

[0145] (Analysis) The storage modulus G' was measured at 25° C. The peak value (maximum value) of tan δ (= G'' / G': where G'' is the loss modulus) was used as an index of viscosity.

[0146] [Curing rate] Under a nitrogen gas atmosphere, a coating film of the sealing composition having a thickness of 10 μm or 20 μm was formed on a glass substrate having dimensions of 50 mm × 50 mm, as shown in Table II below. This coating film was then irradiated with 300 mW / cm under a nitrogen gas atmosphere. ２ The cumulative light intensity under these conditions is 1.5 J / cm ２ The coating film was cured by irradiating it with ultraviolet light having a wavelength of 395 nm (MZ 240 mm 395 nm UVLED manufactured by IST Corporation) so that the integrated light amount was 1.0 J / cm for each of the sealing films 7-1 and 7-2. ２ , 1.8 J / cm ２The obtained cured film (sealing film) and the composition before curing were subjected to FTIR (infrared spectrometer Nexus 870) measurement. In the obtained spectrum, the peak of the C═C bond derived from the (meth)acryloyl group (810 cm －１ The curing rate was calculated from the strength of the cured sealing composition by the following formula: Curing rate (%) = (1 - a / b) x 100, where a is the peak value derived from the C=C bond of the sealing composition before curing, and b is the peak value derived from the C=C bond of the sealing film after curing.

[0147] [Evaluation of Sealing Composition] <Adhesion> A silicon nitride film (SiNx, Vickers hardness HV900) having a thickness of 500 nm was formed on alkali-free glass by plasma CVD. Next, each of the sealing compositions prepared above was applied onto the silicon nitride film by inkjet printing after leaving the film to stand in a thermostatic chamber at 60°C for one week. The formed coating film was then subjected to an ink jet printing at 300 mW / cm under a nitrogen gas atmosphere. ２ Under these conditions, the cumulative light intensity is 1.5 J / cm ２ The coating film was cured by irradiating it with ultraviolet light having a wavelength of 395 nm so that the cumulative light amount was 1.0 J / cm . In this way, evaluation samples of sealing films 1 to 16 were obtained. Note that for sealing films 7-1 and 7-2, the cumulative light amount was 1.0 J / cm . ２ , 1.8 J / cm ２ The ultraviolet light was emitted from MZ (240 mm, 395 nm: UVLED) manufactured by IST Corporation. The silicon nitride film was formed by irradiating the silicon nitride film in a chamber with a reduced pressure and silane (SiH ４ ), ammonia (NH ３ ), hydrogen (H ２ ) was heated and supplied into the chamber to form the sealing film. The thickness of the sealing film was adjusted as shown in Table II below by adjusting the number of inkjet coatings and the resolution. Evaluation was performed by making cuts in the sealing film with a cutter and then performing a peel test using tape (3M 600). In the following evaluation criteria, A, B, and C were rated as passing. (Evaluation criteria) A: Adhesion strength between the sealing film and the silicon nitride film is 3N or more B: Adhesion strength between the sealing film and the silicon nitride film is 2N or more and less than 3N C: Adhesion strength between the sealing film and the silicon nitride film is 1N or more and less than 2N D: Adhesion strength between the sealing film and the silicon nitride film is 0.1N or more and less than 1N

[0148] [Fabrication of Organic EL Element 1] (1) Preparation of Substrate A 15 μm polyimide film was prepared as a film substrate. Further, a gas barrier layer (SiO ２ Film: 250nm / SiNx film: 50nm / SiO ２ Film: 500 nm (upper layer / middle layer / lower layer) was formed by plasma CVD.

[0149] (2) Formation of First Electrode An Al film was formed as a 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 measured using a contact surface profiler (DECTAK). The Al film was formed using a vacuum deposition device at a vacuum degree of 1×10 －４ After reducing the pressure to 100 Pa, a tungsten crucible for resistance heating was used for forming the alloy.

[0150] (3) Formation of Organic EL Layer First, the evaporation crucibles in the vacuum evaporation apparatus were filled with the materials listed below that constitute each layer of the organic functional layer in the optimal amounts for device fabrication. The evaporation crucibles used were made of resistance heating material made of molybdenum or tungsten.

[0151] (3-1) Formation of hole injection layer Vacuum degree 1×10 －４ After reducing the pressure to 10 Pa, an evaporation crucible containing the following compound A-1 was heated by applying an electric current. Then, the compound A-1 was evaporated onto the first electrode (metal layer side) at a deposition rate of 0.1 nm / sec to form a hole injection layer having a thickness of 10 nm.

[0152] (3-2) Formation of Hole Transport Layer Next, an evaporation crucible containing the following compound M-2 was heated by applying electricity, and evaporated onto the hole injection layer at a deposition rate of 0.1 nm / sec to form a hole transport layer with a thickness of 30 nm.

[0153] (3-3) Formation of Light-Emitting Layer Next, Compound BD-1 and Compound H-1 below 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 15-nm-thick light-emitting layer (fluorescent-emitting layer) emitting blue light. Next, Compound GD-1, Compound RD-1 below, and Compound H-2 below were co-deposited at a deposition rate of 0.1 nm / sec so that the concentrations of Compound GD-1 and RD-1 were 20% by mass and 0.5% by mass, respectively. Then, a 15-nm-thick light-emitting layer (phosphorescent-emitting layer) emitting yellow light was formed.

[0154] (3-4) Formation of Electron Transport Layer Thereafter, a heating boat containing the following compound T-1 as an electron transport material was energized to form an electron transport layer. ３ An electron transport layer made of (tris(8-quinolinol)) was formed on the light-emitting layer at a deposition rate of 0.1 to 0.2 nm / sec to a thickness of 30 nm.

[0155] (3-5) Formation of Electron Injection Layer (Metal Affinity Layer) Next, a heating boat containing the following compound I-1 as an electron injection material was heated by applying electricity to form an electron injection layer made of Liq on the electron transport layer. At this time, the deposition rate was set to a range of 0.01 to 0.02 nm / sec, and the thickness was set to 2 nm. This electron injection layer functions as a metal affinity layer. In this way, an organic EL layer that emits white light was formed.

[0156] (4) Formation of Second Electrode Furthermore, a Mg / Ag mixture (Mg:Ag=1:9 (vol ratio)) was vapor-deposited to a thickness of 10 nm to form a second electrode and its lead electrode.

[0157] (5) Formation of a capping layer: After that, the electrode was transferred back to the original vacuum chamber. α-NPD (4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl) was evaporated onto the electrode at a deposition rate of 0.1 to 0.2 nm / sec to a thickness of 40 nm. This formed a capping layer for improving light extraction.

[0158] (6) Formation of First Sealing Layer Next, a silicon nitride (SiNx, Vickers hardness HV900) having a thickness of 500 nm was formed by plasma CVD as a first sealing layer for covering the light-emitting portion of the organic EL element fabricated above.

[0159] (7) Formation of Second Sealing Layer Next, the sealing composition 1 prepared above was left to stand in a thermostatic chamber at 60°C for one week, and then filled into a cartridge-integrated head of an inkjet device under a nitrogen gas atmosphere. Then, the sealing composition 1 after aging was applied to the organic EL element on which the first sealing layer had been formed using an inkjet method under a nitrogen gas atmosphere. Thereafter, the formed coating film was subjected to an irradiation of 300 mW / cm under a nitrogen gas atmosphere. ２ The cumulative light intensity under these conditions is 1.5 J / cm ２ The coating was cured by irradiating it with ultraviolet light having a wavelength of 395 nm (MZ 240 mm 395 nm UVLED manufactured by IST Corporation) so that the thickness of the second sealing layer was set as shown in Table II below by adjusting the number of coatings and the resolution of the inkjet printer.

[0160] (8) Formation of Third Sealing Layer Next, a silicon nitride (SiNx, Vickers hardness HV900) having a thickness of 500 nm was formed as a third sealing layer on the second sealing layer by plasma CVD, thereby obtaining an organic EL element 1 for evaluation in which the first to third sealing layers were formed.

[0161] [Fabrication of Organic EL Elements 2 to 16] Organic EL elements 2 to 16 for evaluation were fabricated in the same manner as in the fabrication of Organic EL element 1, except that the sealing composition 1 used in forming the second sealing layer was changed as shown in the following table. For Organic EL elements 7-1 and 7-2, the sealing composition 1 and film thickness were changed as shown in Table II below, and the integrated light intensity was set to 1.0 J / cm. ２ , 1.8 J / cm ２ The same procedure was followed except that the following changes were made:

[0162] [Evaluation of Organic EL Elements] <Flexibility> Each organic EL element was wrapped around a metal roller with a diameter of 10 mm and left in a thermo-hygrostat chamber under high temperature and high humidity (temperature 60°C, relative humidity 90%) to carry out an accelerated degradation test. At this time, the polyimide film, which is the film substrate, was wrapped so as to be in contact with the metal roller. After 1500 hours, each organic EL element was removed from the thermo-hygrostat chamber and examined under a microscope at room temperature to confirm the luminescence state (dark spot area ratio). Evaluation criteria A, B, and C below were evaluated as passing. (Evaluation criteria) A: Dark spot area ratio less than 0.1% B: Dark spot area ratio 0.1% or more but less than 0.5% C: Dark spot area ratio 0.5% or more but less than 1% D: Dark spot area ratio 1% or more

[0163] <Heat Resistance> Each organic EL element was wrapped around a metal roller with a diameter of 10 mm and left in a thermo-hygrostat chamber at a temperature of 100°C to conduct an accelerated aging test. At this time, the polyimide film, which is the film substrate, was wrapped so as to be in contact with the metal roller. After 1500 hours, each organic EL element was removed from the thermo-hygrostat chamber and examined under a microscope at room temperature to confirm the luminescence state (dark spot area ratio). The following evaluation criteria A, B, and C were evaluated as passing. (Evaluation Criteria) A: Dark spot area ratio less than 0.1% B: Dark spot area ratio 0.1% or more but less than 0.5% C: Dark spot area ratio 0.5% or more but less than 1% D: Dark spot area ratio 1% or more

[0164]

[0165] As shown by the above results, it is recognized that the sealing composition of the present invention is superior in adhesion, flex resistance, and heat resistance to the sealing compositions of the comparative examples.

[0166] The present invention can be used in an inkjet composition for sealing an electronic device, a method for forming an electronic device sealing film, and an electronic device sealing film.

Claims

1. An electronic device sealing composition for inkjet use, which contains a photopolymerizable monomer and a photopolymerization initiator, wherein the photopolymerizable monomer is a (meth)acrylate, and the electronic device sealing composition after curing has a dynamic viscoelasticity such that the loss factor (tan δ) peak value is in the range of 0.3 to 1.0 and the storage modulus (G') is in the range of 1.0 to 3.0 GPa.

2. The composition for electronic device sealing for inkjet printing according to claim 1, wherein the (meth)acrylate is a monofunctional (meth)acrylate, and the content ratio of the monofunctional (meth)acrylate to the total amount of the photopolymerizable monomer is 41 mass% or more.

3. The composition for electronic device sealing for ink jet printing according to claim 1, wherein the (meth)acrylate has a phenyl group.

4. In a nitrogen gas atmosphere, ultraviolet light with a wavelength of 395 nm is applied at 1.5 to 1.8 J / cm ２ 2. The electronic device sealing composition for ink jet application according to claim 1, wherein when cured by irradiation, the resulting electronic device sealing film has a cure rate of 80% or more.

5. A method for forming a sealing film using the composition for electronic device sealing according to any one of claims 1 to 4, comprising the steps of: forming a first sealing layer on an electronic device by a vapor phase method; and forming a second sealing layer by applying the composition for electronic device sealing on the first sealing layer.

6. The method for forming an electronic device sealing film according to claim 5, further comprising a step of forming a third sealing layer on the second sealing layer by a vapor phase method.

7. The method for forming an electronic device sealing film according to claim 5, wherein the step of forming the second sealing layer uses an ink-jet method.

8. An electronic device sealing film for sealing an electronic device, comprising: a first sealing layer containing silicon nitride, silicon oxide or silicon oxynitride; and a second sealing layer using the electronic device sealing composition according to any one of claims 1 to 4.

9. The electronic device sealing film according to claim 8, further comprising a third sealing layer on the second sealing layer, the third sealing layer containing silicon nitride, silicon oxide or silicon oxynitride.

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