CN111345116A

CN111345116A - Encapsulant for organic electroluminescent display element

Info

Publication number: CN111345116A
Application number: CN201880069222.5A
Authority: CN
Inventors: 佐佐木麻希子; 中岛刚介; 栗村启之; 仲田仁; 结城敏尚; 川村宪史
Original assignee: Denka Co Ltd
Current assignee: Denka Co Ltd
Priority date: 2017-10-26
Filing date: 2018-10-25
Publication date: 2020-06-26
Anticipated expiration: 2038-10-25
Also published as: JP2021153061A; TWI773843B; KR102626849B1; KR20200078559A; JPWO2019082996A1; CN111345116B; TW201923018A; JP7203903B2; JP6936330B2; WO2019082996A1

Abstract

An encapsulant for an organic electroluminescent display element, comprising (A) an acyclic alkanediol di (meth) acrylate having 6 or more carbon atoms, (B) a cyclic monomer comprising a cyclic monofunctional (meth) acrylate and a cyclic 2-functional (meth) acrylate, and (C) a photopolymerization initiator, wherein the encapsulant satisfies the following numerical formulae (I) and (III) 8mPa · s ≦ η ≦ 50mPa · s … (I) γ/2 η <0.9m/s … (III) (wherein η represents a viscosity measured by an E-type viscometer at 25 ℃, and γ represents a static surface tension measured by a pendant drop method).

Description

Encapsulant for organic electroluminescent display element

Technical Field

The present invention relates to an encapsulant for an organic Electroluminescent (EL) display element.

Background

Organic Electroluminescence (EL) devices (also referred to as OLED devices) have attracted attention as device bodies capable of emitting light with high luminance. However, the OLED element has a problem that the OLED element is deteriorated by moisture and the light emission characteristics are degraded.

In order to solve such a problem, a technique of sealing an organic EL element and preventing deterioration due to moisture is studied. For example, a method of sealing with a sealing material made of sintered glass is cited (see patent document 1).

It proposes that: an organic electroluminescent display device is characterized in that a sealing layer is a laminate in which at least a barrier layer, a resin layer, and a barrier layer are formed in this order (see patent document 2); an organic EL device is characterized by comprising: an encapsulating layer in which inorganic films and organic films are alternately laminated for encapsulating an organic EL element, and an encapsulating glass substrate which is closely attached to the uppermost organic film of the encapsulating layer and is disposed so as to cover the entire upper surface of the uppermost organic film (see patent document 3).

As a resin composition for encapsulating an organic EL element, there are proposed: an encapsulant for an organic electroluminescent display element, which contains a cyclic ether compound, a cationic polymerization initiator, and a polyfunctional vinyl ether compound (see patent document 4); a cationically polymerizable resin composition containing a cationically polymerizable compound and a photo-cationic polymerization initiator or a thermal cationic polymerization initiator (see patent document 5). As a resin composition for sealing an organic EL element, a (meth) acrylic resin composition has been proposed (patent documents 6 to 11).

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 10-74583

Patent document 2: japanese patent laid-open publication No. 2001-307873

Patent document 3: japanese patent laid-open publication No. 2009-37812

Patent document 4: japanese patent laid-open publication No. 2014-225380

Patent document 5: japanese patent laid-open publication No. 2012-190612

Patent document 6: japanese patent laid-open No. 2014-229496

Patent document 7: japanese laid-open patent publication No. 2014-196387

Patent document 8: japanese patent laid-open publication No. 2014-193970

Patent document 9: japanese patent laid-open publication No. 2014-193971

Patent document 10: WO2014/157642 publication

Patent document 11: US2017/0062762 publication

Disclosure of Invention

Problems to be solved by the invention

However, the conventional techniques described in the above documents have room for improvement in the following respects.

In the case of mass production, patent document 1 adopts a method of sealing the outer peripheral portion of an organic EL element by sandwiching it between substrates having low moisture permeability, such as glass. In this case, since the structure forms a hollow package structure, there is a problem that moisture cannot be prevented from entering the inside of the hollow package structure, which causes deterioration of the organic EL element.

Patent documents 2 to 3 have a problem that the thickness of the organic film is 3 μm or less because the organic film is formed by vapor deposition. If the thickness of the organic film is 3 μm or less, there is a problem as follows: not only particles generated during element formation cannot be completely covered, but also it is difficult to coat the inorganic film while maintaining flatness.

Patent document 4 proposes a sealing agent using an epoxy material, but since curing of such a material requires heating, the organic EL element is damaged, and there is a problem in terms of yield. Patent document 5 proposes a photocurable sealing agent using an epoxy material, but since such a material is cured by UV light, the organic EL element is damaged by the UV light, which causes a problem in terms of yield.

Patent documents 6 to 10 describe reduction in water vapor transmission rate, which is a characteristic required for such a sealing material, but do not describe a problem that the sealing material itself penetrates from a pinhole of a passivation film to lower reliability of an organic EL element, and a countermeasure against the problem.

Patent document 11 describes the use of a cyclic monofunctional (meth) acrylate, but the problem of the formation of an out-gassing of unreacted materials and the occurrence of poor light emission of an organic EL element has not been solved.

As described above, the conventional techniques described above have a problem that both the ejection property when ink is ejected and the reliability of the organic EL element cannot be satisfied.

Means for solving the problems

The present invention has been made in view of the above circumstances, and an object thereof is to provide a composition which is excellent in both the ejection property when ink is ejected and the reliability of an organic EL element when used for sealing an organic EL element.

The present invention can provide the following.

<1>

An encapsulant for an organic electroluminescent display element, comprising: (A) a non-cyclic alkanediol di (meth) acrylate having 6 or more carbon atoms, (B) a cyclic monomer, and (C) a photopolymerization initiator,

(B) the cyclic monomer contains a cyclic monofunctional (meth) acrylate and a cyclic 2-functional (meth) acrylate,

the encapsulant for organic electroluminescent display elements satisfies both the following numerical formulae (I) and (III).

8mPa·s≤η≤50mPa·s…(I)

γ/2η<0.9m/s…(III)

(wherein η represents the viscosity measured at 25 ℃ by means of an E-type viscometer, and γ represents the static surface tension measured by the pendant drop method.)

<2>

the composition contains 10 to 85 parts by mass of the component (A) and 15 to 90 parts by mass of the component (B) per 100 parts by mass of the total of the components (A) and (B),

in 100 parts by mass of the sum total of the cyclic monofunctional (meth) acrylate and the cyclic 2-functional (meth) acrylate, the content ratio of the cyclic monofunctional (meth) acrylate to the cyclic 2-functional (meth) acrylate is, in terms of mass ratio, cyclic monofunctional (meth) acrylate: 10-95% of a cyclic 2-functional (meth) acrylate: 90 to 5, and

the encapsulant for organic electroluminescent display elements satisfies the following numerical formulae (I), (II) and (III) at the same time.

8mPa·s≤η≤50mPa·s…(I)

14mN/m≤γ≤40mN/m…(II)

γ/2η<0.9m/s…(III)

<3>

The sealing agent for an organic electroluminescent display element according to <1> or <2>, wherein the cyclic monomer (B) contains 1 or more kinds of alicyclic monomers.

<4>

The sealing agent for an organic electroluminescent display element according to any one of <1> to <3>, wherein a fluorine-containing monomer having a fluorine atom and a (meth) acryloyl group is contained as the component (E).

<5>

The sealing agent for an organic electroluminescent display element according to <4>, wherein the fluorine atom content of the fluorine-containing monomer is 2 to 70% by mass based on the total amount of the fluorine-containing monomer.

<6>

The sealing agent for an organic electroluminescent display element according to <4> or <5>, wherein the fluorine-containing monomer contains at least one selected from the group consisting of a compound represented by formula (E-1), a compound represented by formula (E-2), and a compound represented by formula (E-3).

Formula (E-1)

[ in the formula (E-1),

R¹represents a hydrogen atom or a methyl group,

R²represents a fluoroalkyl group, or a group in which an oxygen atom is inserted into a part of a carbon-carbon bond and a carbon-hydrogen bond of the fluoroalkyl group. Multiple existence of R³May be the same or different from each other.]

Formula (E-2)

[ in the formula (E-2),

R³represents a hydrogen atom or a methyl group,

R⁴denotes a fluoroalkanediyl group or a carbon-carbon group in the fluoroalkanediyl groupA group in which an oxygen atom is inserted into a part of the bond and the carbon-hydrogen bond. Multiple existence of R³May be the same or different from each other.]

Formula (E-3)

[ in the formula (E-3),

R⁵represents a hydrogen atom or a methyl group,

R⁶represents a single bond, an alkanediyl group, a fluoroalkanediyl group, or a group in which an oxygen atom is inserted into a carbon-carbon bond and a part of a carbon-hydrogen bond in the alkanediyl group or the fluoroalkanediyl group,

Ar¹represents a fluorinated aryl group.]

<7>

The sealing agent for an organic electroluminescent display element according to <6>, wherein the fluorine-containing monomer contains at least one selected from the group consisting of a compound represented by formula (E-1-1), a compound represented by formula (E-2-1), and a compound represented by formula (E-3-1).

Formula (E-1-1)

[ formula (E-1-1) wherein R¹Represents a hydrogen atom or a methyl group, R²¹Represents a hydrogen atom or a fluorine atom, and n represents an integer of 1 or more. Multiple existence of R²¹May be the same or different from each other. Wherein R is²¹At least one of which is a fluorine atom.]

Formula (E-2-1)

[ formula (E-2-1) wherein R³Represents a hydrogen atom or a methyl group, R⁴¹Represents a hydrogen atom or a fluorine atom, and m represents an integer of 1 or more. Multiple existence of R⁴¹May be the same or different from each other. Wherein R is⁴¹At least one of which is a fluorine atom. Multiple storagesAt R of³May be the same or different from each other.]

Formula (E-3-1)

[ formula (E-3-1) wherein R⁵Represents a hydrogen atom or a methyl group, R⁶¹Represents a hydrogen atom or a fluorine atom, R⁶²Represents a hydrogen atom or a fluorine atom, and p represents an integer of 0 or more. Multiple existence of R⁶¹May be the same or different from each other. Multiple existence of R⁶²May be the same or different from each other. Wherein R is⁶²At least one of which is a fluorine atom.]

<8>

The sealing agent for an organic electroluminescent display element according to any one of <4> to <7>, wherein the content of the component (E) is in a range of 0.1 to 10 parts by mass with respect to 100 parts by mass of the total of the components (A) and (B).

<9>

The sealing agent for an organic electroluminescent display element according to any one of <4> to <8>, wherein the component (E) contains one or more selected from the group consisting of 2,2,3,3,4,4,5,5,6,6,7,7,8,8,9, 9-hexadecafluoro-1, 10-decanediol di (meth) acrylate, 1H, 5H-octafluoropentyl (meth) acrylate and 1H,1H,2H, 2H-tridecafluorooctyl (meth) acrylate.

<10>

The sealing agent for an organic electroluminescent display element according to any one of <1> to <9>, which is applied by an inkjet method.

<11>

The encapsulant for organic electroluminescent display elements according to any one of <1> to <10>, characterized by not containing a 2-functional (meth) acrylate oligomer, a 2-functional (meth) acrylate polymer, a polyfunctional (meth) acrylate oligomer, or a polyfunctional (meth) acrylate polymer.

<12>

The sealing agent for an organic electroluminescent display element according to any one of <1> to <11>, wherein a glass transition temperature of a cured product is 65 ℃ or more and 120 ℃ or less.

<13>

The sealing agent for an organic electroluminescent display element according to any one of <1> to <12>, wherein at least 1 of the component (B) has 2 or more cyclic structures in a molecule.

<14>

The sealing agent for an organic electroluminescent display element according to any one of <1> to <13>, wherein at least 2 of the component (B) has 2 or more cyclic structures in a molecule.

<15>

The sealing agent for an organic electroluminescent display element according to any one of <1> to <14>, wherein the component (B) contains 1 or more selected from the group consisting of ethoxylated o-phenylphenol (meth) acrylate, m-phenoxybenzyl (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, and ethoxylated bisphenol A di (meth) acrylate represented by the following structural formula.

(wherein R is each independently a hydrogen atom or a methyl group; m, n, m + n in the formula: 2. about.10)

<16>

The sealing agent for an organic electroluminescent display element according to any one of <1> to <15>, wherein the component (A) is an alkanediol di (meth) acrylate having 12 or less carbon atoms.

<17>

The sealing agent for an organic electroluminescent display element according to any one of <1> to <16>, wherein the component (A) contains 1 or more selected from the group consisting of 1, 9-nonanediol di (meth) acrylate, 1, 10-decanediol di (meth) acrylate, and 1, 12-dodecanediol di (meth) acrylate.

<18>

The encapsulant for organic electroluminescent display elements according to any one of <1> to <17>, wherein the component (C) contains 2,4, 6-trimethylbenzoyl-diphenyl-phosphine oxide.

<19>

The sealing agent for an organic electroluminescent display element according to any one of <1> to <18>, wherein the content of the component (C) is 0.5 to 4 parts by mass.

<20>

The sealing agent for an organic electroluminescent display element according to any one of <1> to <19>, which further comprises (D) an antioxidant.

<21>

The sealing agent for an organic electroluminescent display element according to <20>, wherein the component (D) is a hindered phenol antioxidant.

<22>

The sealing agent for an organic electroluminescent display element according to <20> or <21>, which contains 2 or more kinds of the component (D).

<23>

The sealing agent for an organic electroluminescent display element according to any one of <1> to <22>, which is characterized by being cured at a wavelength of 395nm to 500 nm.

<24>

The encapsulant for organic electroluminescent display elements as described in <23>, which is cured by using 395nm LED lamp.

<25>

A cured product obtained by curing the sealing agent for an organic electroluminescent display element according to any one of <1> to <24 >.

<26>

An organic EL device comprising the cured product of <25 >.

<27>

A display comprising the cured product of <25 >.

<28>

A display having flexibility, which comprises the cured product of <25 >.

<29>

An organic EL device having flexibility, which comprises the cured product of <25 >.

ADVANTAGEOUS EFFECTS OF INVENTION

The sealing agent of the present invention exhibits excellent ejection properties when ink is used, and also exhibits excellent reliability of the obtained organic EL device.

Detailed Description

The present embodiment will be described below. The numerical ranges recited in the present specification include upper and lower limits unless otherwise specified. In the present specification, the following definitions are adopted unless otherwise stated. The expression "(meth) acrylate" means acrylate or methacrylate, and the expressions "(meth) acryloyloxy", "meth) acrylamide" and the like have the same meanings. "monofunctional (meth) acrylate" means a (meth) acrylate having 1 (meth) acryloyl group, and "2-functional (meth) acrylate" means a (meth) acrylate having 2 (meth) acryloyl groups. "polyfunctional (meth) acrylate" means a (meth) acrylate having 3 or more (meth) acryloyl groups, excluding 2-functional (meth) acrylates.

Hereinafter, a top emission type organic EL device in which light is emitted from the side opposite to the substrate of the organic EL element formed on the substrate will be described as an example. The organic EL device of top emission type has a structure in which the following elements are sequentially formed: an organic EL element in which an anode, an organic EL layer including a light-emitting layer, and a cathode are sequentially stacked on a substrate; an encapsulation layer formed of a laminate of an inorganic film and an organic film covering the entire organic EL element; and a package substrate disposed on the package layer.

As the substrate, various substrates such as a glass substrate, a silicon substrate, and a plastic substrate can be used. Of these, 1 or more of the group consisting of glass substrates and plastic substrates are preferable, and glass substrates are more preferable.

Examples of the plastic used for the plastic substrate include: polyimide, polyetherimide, polyethylene terephthalate, polyethylene naphthalate, polyoxadiazole, aromatic polyamide, polybenzimidazole, polybenzobithiazole, polybenzoxazole, polythiazole, polythene, polymethyl methacrylate, polystyrene, polycarbonate, polycycloolefin, polyacrylic, and the like. Among these, in terms of excellent low moisture permeability, low oxygen permeability, and heat resistance, 1 or more of the group consisting of polyimide, polyetherimide, polyethylene terephthalate, polyethylene naphthalate, polyoxadiazole, aromatic polyamide, polybenzimidazole, polybenzobithiazole, polybenzoxazole, polythiazole, and polyethylene terephthalate are preferable, and in terms of high permeability to energy rays such as ultraviolet rays or visible light, 1 or more of the group consisting of polyimide, polyetherimide, polyethylene terephthalate, and polyethylene naphthalate are more preferable.

As the anode, a conductive metal oxide film, a translucent metal thin film, or the like having a large work function (preferably, a work function of more than 4.0 eV) is generally used. Examples of the material of the anode include: metal oxides such as indium tin Oxide (hereinafter referred to as ITO) and tin Oxide, metals such as gold (Au), platinum (Pt), silver (Ag) and copper (Cu), or alloys containing at least 1 of these metals, polyaniline or a derivative thereof, and organic transparent conductive films such as polythiophene or a derivative thereof. If necessary, the anode may be formed of a layer structure of 2 or more layers. The film thickness of the anode can be appropriately selected in consideration of the electrical conductivity (in the case of a bottom emission type, light transmittance). The thickness of the anode is preferably 10nm to 10 μm, more preferably 20nm to 1 μm, and most preferably 50nm to 500 nm. Examples of the method for producing the anode include: vacuum deposition, sputtering, ion plating, and the like. In the case of the top emission type, a reflective film for reflecting light emitted to the substrate side may be provided under the anode.

The organic EL layer includes at least a light-emitting layer formed of an organic material. The light-emitting layer contains a light-emitting material. Examples of the light-emitting material include organic materials (low-molecular compounds or high-molecular compounds) that emit fluorescence or phosphorescence. The light emitting layer may further contain a doping material. Examples of the organic substance include: dye-based materials, metal complex-based materials, polymer materials, and the like. The dopant is doped into the organic material for the purpose of improving the light emission efficiency of the organic material, changing the emission wavelength, and the like. The thickness of the light-emitting layer formed of these organic materials and a dopant doped as necessary is usually 2 to 200 nm.

(pigment series material)

Examples of the coloring material include: methylcyclopentamine (cyclopropenamine) derivatives, tetraphenylbutadiene derivative compounds, triphenylamine derivatives, oxadiazole derivatives, pyrazoloquinoline derivatives, distyrylbenzene derivatives, distyrylarylene derivatives, pyrrole derivatives, thiophene ring compounds, pyridine ring compounds, perinone derivatives, perylene derivatives, oligothiophene derivatives, trifumaramylamine (trifumalylamine) derivatives, oxadiazole dimers, pyrazoline dimers, and the like.

(Metal Complex Material)

Examples of the metal complex material include: metal complexes such as iridium complexes and platinum complexes having luminescence from a triplet excited state, aluminum hydroxyquinoline complexes, benzohydroxyquinoline beryllium complexes, benzoxazolyl zinc complexes, benzothiazolyl zinc complexes, azomethyl zinc complexes, porphyrin zinc complexes, and europium complexes. Examples of the metal complex include: the central metal includes rare earth metals such as terbium (Tb), europium (Eu) and dysprosium (Dy), metal complexes such as aluminum (Al), zinc (Zn) and beryllium (Be), and the like, and metal complexes having a ligand having a structure of oxadiazole, thiadiazole, phenylpyridine, phenylbenzimidazole, quinoline, and the like. Among these, metal complexes in which the central metal has aluminum (Al), the ligand has a quinoline structure, and the like are preferable. Among metal complexes in which the central metal has aluminum (Al), the ligand has a quinoline structure, and the like, tris (8-hydroxyquinoline) aluminum is preferable.

(Polymer Material)

Examples of the polymer material include: poly (p-phenylene vinylene) derivatives, polythiophene derivatives, poly (p-phenylene) derivatives, polysilane derivatives, polyacetylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, and substances obtained by polymerizing the above-mentioned color bodies and metal complex-based light-emitting materials.

Among the above luminescent materials, examples of materials that emit blue light include: distyrylarylene derivatives, oxadiazole derivatives, polyvinylcarbazole derivatives, polyparaphenylene derivatives, polyfluorene derivatives, and polymers thereof. Among these, a polymer material is preferable. Among the polymer materials, 1 or more of the group consisting of polyvinylcarbazole derivatives, polyparaphenylene derivatives, and polyfluorene derivatives is preferable.

Examples of the green light-emitting material include: quinacridone derivatives, coumarin derivatives, polyparaphenylene vinylene derivatives, polyfluorene derivatives, and polymers thereof. Among these, a polymer material is preferable. Among the polymer materials, 1 or more of the group consisting of a poly (p-phenylene vinylene) derivative and a polyfluorene derivative is preferable.

Examples of the material emitting red light include: coumarin derivatives, thiophene ring compounds, poly (p-phenylene vinylene) derivatives, polythiophene derivatives, polyfluorene derivatives, and polymers thereof. Among these, a polymer material is preferable. Among the polymer materials, 1 or more of the group consisting of a poly (p-phenylene vinylene) derivative, a polythiophene derivative, and a polyfluorene derivative is preferable.

(doping Material)

As the doping material, there can be mentioned: perylene derivatives, coumarin derivatives, rubrene derivatives, quinacridone derivatives, squaraine derivatives, porphyrin derivatives, styrene-based pigments, tetracene derivatives, pyrazolone derivatives, cyclododecene, phenoxazinone, and the like.

The organic EL layer may be provided as appropriate in addition to the light-emitting layer: a layer provided between the light-emitting layer and the anode, and a layer provided between the light-emitting layer and the cathode. First, examples of the layer provided between the light-emitting layer and the anode include: a hole injection layer for improving the efficiency of injecting holes from the anode, a hole transport layer for transporting holes injected from the anode or the hole injection layer to the light-emitting layer, and the like. Examples of the layer provided between the light-emitting layer and the cathode include: an electron injection layer for improving the injection efficiency of electrons from the cathode, an electron transport layer for transporting electrons injected from the cathode or the electron injection layer to the light-emitting layer, and the like.

(hole injection layer)

Examples of the material for forming the hole injection layer include: anilines such as 4', 4 ″ -tris { 2-naphthyl (phenyl) amino } triphenylamine, starburst amines, oxides such as phthalocyanine, vanadium oxide, molybdenum oxide, ruthenium oxide, and aluminum oxide, amorphous carbon, polyaniline, and polythiophene derivatives.

(hole transport layer)

Examples of the material constituting the hole transport layer include: polyvinylcarbazole or a derivative thereof, polysilane or a derivative thereof, polysiloxane derivative having an aromatic amine in a side chain or a main chain, pyrazoline derivative, arylamine derivative, stilbene derivative, triphenyldiamine derivative, benzidine derivative, polyaniline or a derivative thereof, polythiophene or a derivative thereof, polyarylamine or a derivative thereof, polypyrrole or a derivative thereof, poly (p-phenylene vinylene) or a derivative thereof, poly (2, 5-thienylene vinylene) or a derivative thereof, and the like.

When the hole injection layer or the hole transport layer has a function of blocking electron transport, the hole transport layer or the hole injection layer may be referred to as an electron blocking layer.

(Electron transport layer)

Examples of the material constituting the electron transport layer include: oxadiazole derivatives, anthraquinone dimethane or its derivatives, benzoquinone or its derivatives, naphthoquinone or its derivatives, anthraquinone or its derivatives, tetracyanoanthraquinone dimethane or its derivatives, fluorenone derivatives, diphenyldicyanoethylene or its derivatives, diphenoquinone derivatives, 8-hydroxyquinoline or its derivatives, polyquinoline or its derivatives, polyquinoxaline or its derivatives, polyfluorene or its derivatives, and the like. Examples of the derivative include a metal complex. Of these, 8-hydroxyquinoline or a derivative thereof is preferable. Among 8-quinolinol or a derivative thereof, tris (8-quinolinol) aluminum is preferable in that it can also be used as a fluorescent or phosphorescent organic substance contained in the light-emitting layer.

(Electron injection layer)

The electron injection layer may be, depending on the type of the light-emitting layer: an electron injection layer having a single-layer structure of a calcium (Ca) layer, a single-layer structure of a layer having 1 or more kinds selected from the group consisting of metals belonging to group IA and group IIA of the periodic Table of elements and having a work function of 1.5 to 3.0eV, and oxides, halides and carbonates of the metals, and an electron injection layer having a laminated structure of a layer having 1 or more kinds selected from the group consisting of metals belonging to group IA and group IIA of the periodic Table of elements and having a work function of 1.5 to 3.0eV, and oxides, halides and carbonates of the metals, and a Ca layer. Examples of the metal of group IA of the periodic table having a work function of 1.5 to 3.0eV, or an oxide, halide or carbonate thereof include: lithium (Li), lithium fluoride, sodium oxide, lithium carbonate, and the like. Examples of the metal of group IIA of the periodic Table of the elements having a work function of 1.5 to 3.0eV, or an oxide, halide or carbonate thereof include: strontium (Sr), magnesium oxide, magnesium fluoride, strontium fluoride, barium fluoride, strontium oxide, magnesium carbonate, and the like.

When these electron transport layers or electron injection layers have a function of blocking hole transport, these electron transport layers or electron injection layers may be referred to as hole blocking layers.

As the cathode, a transparent or translucent material having a small work function (suitably, having a work function of less than 4.0 eV) and easily injecting electrons into the light-emitting layer is preferable. Examples of the material of the cathode include: metals such as lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), aluminum (Al), scandium (Sc), vanadium (V), zinc (Zn), yttrium (Y), indium (In), cerium (Ce), samarium (Sm), europium (Eu), terbium (Tb), and ytterbium (Yb), alloys of 2 or more of the above metals, alloys of 1 or more of these with 1 or more of gold (Au), silver (Ag), platinum (Pt), copper (Cu), chromium (Cr), manganese (Mn), titanium (Ti), cobalt (Co), nickel (Ni), tungsten (W), and tin (Sn), or graphite intercalation compounds, or metal oxides such as ITO and tin oxide.

The cathode may be formed in a stacked structure of 2 or more layers. Examples of the 2-layer or more laminated structure include: and a laminated structure of the above metal, metal oxide, fluoride, or alloy thereof and a metal such as Al, Ag, or Cr. The film thickness of the cathode can be appropriately selected in consideration of conductivity and durability. The thickness of the cathode film is preferably 10nm to 10 μm, more preferably 15nm to 1 μm, and most preferably 20nm to 500 nm. Examples of the method for producing the cathode include: vacuum deposition, sputtering, lamination of a metal thin film by thermocompression bonding, and the like.

The layers provided between these light-emitting layers and the anode and between the light-emitting layers and the cathode can be appropriately selected in accordance with the performance required for the organic EL device to be manufactured. For example, the organic EL element used in this embodiment may have any of the following layer configurations (i) to (xv).

(i) Anode/hole transport layer/light emitting layer/cathode

(ii) Anode/luminescent layer/electron transport layer/cathode

(iii) Anode/hole transport layer/light-emitting layer/electron transport layer/cathode

(iv) Anode/hole injection layer/light emitting layer/cathode

(v) Anode/light emitting layer/electron injection layer/cathode

(vi) Anode/hole injection layer/light-emitting layer/electron injection layer/cathode

(vii) Anode/hole injection layer/hole transport layer/light emitting layer/cathode

(viii) Anode/hole transport layer/light emitting layer/electron injection layer/cathode

(ix) Anode/hole injection layer/hole transport layer/light emitting layer/electron injection layer/cathode

(x) Anode/hole injection layer/light-emitting layer/electron transport layer/cathode

(xi) Anode/luminescent layer/electron transport layer/electron injection layer/cathode

(xii) Anode/hole injection layer/luminescent layer/electron transport layer/electron injection layer/cathode

(xiii) Anode/hole injection layer/hole transport layer/light emitting layer/electron transport layer/cathode

(xiv) Anode/hole transport layer/light emitting layer/electron transport layer/electron injection layer/cathode

(xv) Anode/hole injection layer/hole transport layer/light emitting layer/electron transport layer/electron injection layer/cathode

(Here, "/" indicates that the layers are stacked adjacently, the same applies hereinafter.)

The encapsulating layer is provided for preventing a gas such as water vapor or oxygen from contacting the organic EL element, and for encapsulating the organic EL element with a layer having a high barrier property against the gas. The packaging layer alternately forms an inorganic film and an organic film from bottom to top. The inorganic/organic laminate may be formed by repeating 2 or more times.

In an active matrix display device in which a current flowing to each organic EL element is controlled by a Thin Film Transistor (TFT) provided for each pixel, irregularities of 0.5 to 3 μm due to a partition wall separating the TFT, blue, green, and red pixels are present between a cathode or anode and an encapsulation layer. In the active matrix display device, it is necessary to flatten the unevenness by the encapsulating layer to reduce the influence of interference with light emission and further improve the encapsulating performance. If the sealing layer is formed by the sealing agent of the present embodiment, an effect that good flatness can be obtained is exhibited.

The inorganic film of the inorganic/organic laminate is a film provided to prevent the organic EL element from being exposed to a gas such as water vapor or oxygen present in the environment in which the organic EL device is placed. The inorganic film of the inorganic/organic laminate is preferably a continuous, dense film with few defects such as pinholes. Examples of the inorganic film include: SiN film, SiO film, SiON film, Al film₂O₃A single-layer film such as a film or an AlN film, a laminated film of these films, or the like.

The organic film of the inorganic/organic laminate is provided to cover defects such as pinholes formed in the inorganic film and to impart flatness to the surface. The organic film is formed in a region narrower than a region where the inorganic film is formed. This is because if the organic film is formed in the same or a wider area than the formation area of the inorganic film, the organic film is deteriorated in the exposed area. However, the uppermost organic film formed on the uppermost layer of the entire package layer may be formed in substantially the same region as the region where the inorganic film is formed. The upper surface of the encapsulation layer is planarized. As the organic film, a composition having an adhesive function with good adhesion to the inorganic film can be used.

An object of the present embodiment is to provide a sealing agent for an organic electroluminescent display element, for example, for forming the organic film, which is suitable for inkjet coating that enables coating with excellent flatness of a film thickness of 3 μm or more in a short time, has excellent ejection properties by inkjet and flatness after inkjet coating, has barrier properties against water vapor and the like (hereinafter also referred to as low moisture permeability), and does not cause permeation of the sealing agent itself from pinholes in the inorganic film and deterioration of reliability of the organic EL element. If a coating method based on an ink-jet method is used, an organic film can be formed uniformly at a high speed.

If the sealing agent itself penetrates through the pinholes in the inorganic film, not only does the OLED element around the pinholes no longer emit light, but also the sealing agent penetrates into the organic light-emitting material layer during long-term use, leading to increased emission defects and so-called dark spots. That is, the reliability of the OLED element is significantly reduced.

However, according to Lucas-walsh-Washburn (expression 1), which is a basic formula for liquid penetration, the penetration depth l into the pin hole depends on the time (t) after the liquid and the solid are brought into contact, the pore diameter (r), the viscosity (η) of the liquid, the surface tension (γ) of the liquid, and the contact angle (θ) with the solid surface.

In formula 1, the contact angle θ with the solid surface and the pore diameter r are parameters depending on the inorganic film, and therefore, it was found that the reliability of the organic EL element is improved by controlling the permeation rate by formula 2 as the encapsulant.

Gamma/2 η <0.9m/s … formula 2

As described later, the organic EL element has a problem that a dark spot is generated due to permeation of the sealing agent, and a light emission failure is caused. By satisfying the condition of the above formula 2, the permeation of the encapsulant can be suppressed.

The viscosity of the composition of the present embodiment is preferably 8 to 50mPa · s as measured with an E-type viscometer at 25 ℃ and 100 rpm. In the case where ejection by ink jet is difficult, the ink jet head is appropriately heated. If the viscosity is less than 8 mPas, the applied sealing agent for organic EL display element flows out of the organic EL display element before curing, and flows into pinholes in the inorganic film, thereby lowering the reliability of the OLED element. If the viscosity exceeds 50 mPas, it becomes difficult to apply the ink by ink jet. The viscosity of the composition is more preferably 8 to 25 mPas.

The static surface tension of the composition of the present embodiment is preferably 14mN/m or more and 40mN/m or less. The static surface tension is measured by a plate method, a loop method, a pendant drop method, or the like, and the value of the static surface tension defined in the present embodiment is based on the pendant drop method. The pendant drop method is a method of extruding a liquid from the tip of a tube and calculating the surface tension from the shape of a hanging drop (pendant drop). If the static surface tension is less than 14mN/m, the applied encapsulant for the organic EL display element may flow out of the organic EL display element before curing, and may flow into pinholes on the inorganic film, lowering the reliability of the OLED element. If the static surface tension exceeds 40mN/m, it becomes difficult to perform ink jet-based coating. The static surface tension of the composition is more preferably 20mN/m to 30 mN/m.

The composition of the present embodiment is a (meth) acrylic resin composition containing (a) acyclic alkanediol di (meth) acrylate having 6 or more carbon atoms, (B) a cyclic monomer, and (C) a photopolymerization initiator. The component (B) contains at least a cyclic monofunctional (meth) acrylate and a cyclic 2-functional (meth) acrylate.

(A) The acyclic alkanediol di (meth) acrylate having 6 or more carbon atoms is a 2-functional (meth) acrylate having 6 or more carbon atoms of alkane as a main chain, which is a component (a) having no cyclic molecular structure, preferably α, ω -linear alkanediol di (meth) acrylate, more preferably having 12 or less carbon atoms of alkane as a main chain, α, ω -linear alkanediol di (meth) acrylate, more preferably 1 or more species of 1, 6-hexanediol di (meth) acrylate, 1, 9-nonanediol di (meth) acrylate, 1, 10-decanediol di (meth) acrylate, 1, 12-dodecanediol di (meth) acrylate, more preferably 1 or more species of 1, 9-nonanediol di (meth) acrylate, 1, 10-decanediol di (meth) acrylate, 1, 12-dodecanediol di (meth) acrylate, and most preferably 1 or more species of 1, 12-dodecanediol di (meth) acrylate, and preferably 1 or more species of 1, 12-dodecanediol di (meth) acrylate, which may be different from the branched alkane diol (meth) acrylate, and the component (a) may be a branched alkane (meth) having no cyclic molecular structure.

The content of the component (A) is preferably 10 to 85 parts by mass based on 100 parts by mass of the total of the components (A) and (B). If the content of (a) is 10 parts by mass or more, low moisture permeability can be obtained, and if it is 85 parts by mass or less, viscosity increases and reliability of the organic EL element improves. The content of (A) is preferably 30 to 70 parts by mass, more preferably 35 to 68 parts by mass, and most preferably 45 to 65 parts by mass in terms of low moisture permeability and reliability of the organic EL element.

(B) The cyclic monomer is a monomer having a group having a cyclic structure in a molecule and having 1 or more unsaturated double bond groups selected from the group consisting of a (meth) acrylate group, a (meth) acrylamide group, and an N-vinyl group. That is, the component (B) having a cyclic structure is different from the component (A) having a non-cyclic structure. Examples of such a cyclic structure include monomers having a heteroatom-containing cyclic structure such as a cyclic amide group, a tetrahydrofuranyl group, or a piperidyl group, an aromatic hydrocarbon cyclic structure, and an aliphatic hydrocarbon cyclic structure. Among them, 1 or more kinds of monomers having an aromatic hydrocarbon-based cyclic structure and an aliphatic hydrocarbon-based cyclic structure are preferable in terms of ejection properties by inkjet and low moisture permeability. More preferably, a cyclic (meth) acrylate monomer having an aromatic hydrocarbon ring structure or an aliphatic hydrocarbon ring structure can be used as the component (B). The component (B) preferably does not have a fluorine atom and is different from the component (E) described later.

Examples of the (meth) acrylate having a cyclic structure of an aromatic hydrocarbon include: benzyl (meth) acrylate, 4-butylphenyl (meth) acrylate, phenyl (meth) acrylate, 2,4, 5-tetramethylphenyl (meth) acrylate, 4-chlorophenyl (meth) acrylate, phenoxymethyl (meth) acrylate, phenoxyethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate (2-HPA), 2- (meth) acryloyloxyhexahydrophthalic acid, 2- (meth) acryloyloxyethyl-2-hydroxypropylphthalic acid, EO-modified phenol (meth) acrylate, EO-modified cresol (meth) acrylate, EO-modified nonylphenol (meth) acrylate, PO-modified nonylphenol (meth) acrylate, ethoxylated phenylphenol (meth) acrylate, and mixtures thereof, Monofunctional (meth) acrylates having an aromatic hydrocarbon-based cyclic structure of 1 or more in the molecule, such as m-phenoxybenzyl (meth) acrylate, and 2-functional (meth) acrylates such as ethoxylated bisphenol a di (meth) acrylate, propoxylated ethoxylated bisphenol a di (meth) acrylate, and bisphenol a epoxy di (meth) acrylate. These may be used in combination of 1 or more. In particular, in the sealing agent for an organic electroluminescent display element of the present embodiment, it is preferable that the sealing agent has 2 or more cyclic structures in a molecule in terms of low moisture permeability and reliability of an organic EL element. The (meth) acrylate having a cyclic structure of 2 or more aromatic hydrocarbons in the molecule is preferably 1 or more selected from the group consisting of ethoxylated o-phenylphenol (meth) acrylate, m-phenoxybenzyl (meth) acrylate, and ethoxylated bisphenol a di (meth) acrylate, and more preferably 1 or more selected from the group consisting of ethoxylated o-phenylphenol (meth) acrylate and ethoxylated bisphenol a di (meth) acrylate.

Examples of the alicyclic hydrocarbon group in the monomer having a cyclic structure of aliphatic hydrocarbon include: a group having a dicyclopentadiene skeleton such as dicyclopentyl group and dicyclopentenyl group, a cyclohexyl group, an isobornyl group, a cyclodecyltrienyl group (cyclododecatriene), a norbornyl group, an adamantyl group, and the like. Among these, a group having a dicyclopentadiene skeleton is preferable. Examples of the (meth) acrylate having an alicyclic hydrocarbon group include: cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentanyloxyethyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, isobornyl (meth) acrylate, methoxylated cyclodecyltrienyl (meth) acrylate, and the like. The (meth) acrylate having a dicyclopentadiene skeleton is preferably 1 or more selected from the group consisting of tricyclodecane dimethanol di (meth) acrylate, dicyclopentanyloxyethyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, and 1 or more selected from the group consisting of dicyclopentanyl (meth) acrylate and tricyclodecane dimethanol di (meth) acrylate is more preferable in terms of low moisture permeability.

The present inventors have found that the cyclic monomer (B) needs to contain a mixture of a cyclic monofunctional (meth) acrylate and a cyclic 2-functional (meth) acrylate at a predetermined ratio. This is based on the following reason. Cyclic monofunctional (meth) acrylates have a large effect on low moisture permeability but have a low boiling point, and therefore have a problem that an unreacted material forms an external gas, which causes poor light emission of an organic EL element. The cyclic 2-functional (meth) acrylate has a problem that it has a high viscosity and thus has an adverse effect on the ink ejection property, although it is excellent in low moisture permeability and low volatility and therefore has a great effect on the reliability of an OLED device. The present inventors have found that the effect of satisfying both low moisture permeability and OLED element reliability, which has been difficult to achieve by the prior art, can be obtained by using a cyclic monofunctional (meth) acrylate and a cyclic 2-functional (meth) acrylate at a predetermined ratio in combination, and have arrived at the present invention. That is, the content ratio of the monofunctional (meth) acrylate to the 2-functional (meth) acrylate is preferably, in terms of a mass ratio, in 100 parts by mass of the sum of the methacrylate and the acrylate: 2-functional (meth) acrylate 10 to 95: 90 to 5, more preferably 40 to 90: 60 to 10, most preferably 65 to 85: 35 to 15.

The cyclic monofunctional (meth) acrylate is preferably any of the following compounds.

A cyclic monofunctional (meth) acrylate represented by the following structural formula:

(R in the above formula₁Each independently represents a hydrogen atom or a methyl group, and n preferably has an average value of 1 to 10, and n is particularly preferably 1. ) And a cyclic monofunctional (meth) acrylate represented by the following structural formula:

(Y in the above formula is-CH)₂-、-(CH(R⁵)CH₂O)_m1-、-(CH(R⁵)CH₂S)_m2- (wherein, R)⁵Is a hydrogen atom or a methyl group, m1 and m2 are a number of 1 to 4), R³Is a hydrogen atom or a methyl group, R⁴Any substituent represented by the following structural formula).

As the cyclic 2-functional (meth) acrylate, an ethoxylated bisphenol A di (meth) acrylate compound represented by the following structural formula is preferable. In the formula, R is independently a hydrogen atom or a methyl group. In the formula, m and n are preferably 2 to 10.

Preferably, at least 1 of the components (B) has 2 or more cyclic structures in the molecule, and more preferably at least 2 has 2 or more cyclic structures in the molecule.

The content of the component (B) is preferably 15 to 90 parts by mass based on 100 parts by mass of the total of the components (A) and (B). If the content of (B) is 15 parts by mass or more, the viscosity increases and the reliability of the organic EL element improves, and if it is 90 parts by mass or less, the ink jet coatability is excellent. (B) The content of (b) is preferably 30 to 70 parts by mass, more preferably 32 to 65 parts by mass, and most preferably 45 to 65 parts by mass in terms of low moisture permeability and reliability of the organic EL element.

(C) The photopolymerization initiator is preferably a photo radical polymerization initiator, and examples of the photo radical polymerization initiator include benzophenone and derivatives thereof, benzoin and derivatives thereof, anthraquinone and derivatives thereof, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isobutyl ether, benzoin dimethyl ketal and other benzoin derivatives, diethoxyacetophenone, 4-tert-butyltrichloroacetophenone derivatives such as 4-tert-butyltrichloroacetophenone, 2-dimethylaminoethylbenzoate, p-dimethylaminoethylbenzoate, diphenyldisulfide, thioxanthone and derivatives thereof, camphorquinone, 7-dimethyl-2, 3-dioxobicyclo [2.2.1] heptane-1-carboxylic acid, 7-dimethyl-2, 3-dioxobicyclo [2.2.1] heptane-1-carboxyethyl ester, 7-dimethylethoxyphenylketopyrrolidine-2.1 ] heptane-1-carboxymethylether, and benzyl-2-ethoxyphenylketopyrrolidine-2-methyl ether, and when the photo radical polymerization initiator is used, the photo radical polymerization initiator is preferably a compound which causes no damage to the reaction with a visible light, and no less, and no damage to the compound such as benzophenone, benzophenone derivatives, benzophenone, 7, and no less than 2-methoxy-2-1-methoxy-2-methoxy-2-1-methoxy-2-methoxy-1-methoxy-2-methyl ketone, and no less than 4-methoxy-2-methoxy-2-methoxy-2-1-2-methoxy-2-methoxy-1-methyl-methoxy-2-methoxy-2-1-methyl ketone, and no less than 4-methoxy-2-methoxy-2-methoxy-2-methoxy-methyl ketone, and no less than 4-2-methoxy-2-methoxy-2-methoxy-2-methoxy-2-methoxy.

The content of the photopolymerization initiator (C) is preferably 0.05 to 6 parts by mass, more preferably 0.5 to 4 parts by mass, most preferably 2 to 3.9 parts by mass, and most preferably 2.5 to 3.5 parts by mass, based on 100 parts by mass of the total of the component (A) and the component (B). If the content of the component (C) is 0.05 parts by mass or more, the effect of accelerating curing can be obtained reliably, and if it is 6 parts by mass or less, the transmittance of visible light is not reduced when used in a display.

In the composition of the present embodiment, the (meth) acrylate is preferably a monomer in terms of inkjet ejectability. (A) The component (B) is preferably a monomer. The molecular weight of the monomer is preferably 1000 or less. In terms of ink jet ejection properties, the 2-functional (meth) acrylate oligomer/polymer and the polyfunctional (meth) acrylate oligomer/polymer are preferably contained in an amount of 3 parts by mass or less, more preferably 1 part by mass or less, and most preferably not contained in 100 parts by mass of the (meth) acrylate containing the component (a) and the component (B).

In the composition of the present embodiment, it is preferable that a fluorine-containing monomer having a fluorine atom and a (meth) acryloyl group is contained as the component (E) from the viewpoint of obtaining high flatness by lowering the free energy of the surface after application. In addition, the (meth) acryloyl group means an acryloyl group or a methacryloyl group. The fluorine-containing monomer may be used alone in 1 kind, or 2 or more kinds may be used in combination.

(E) The content of the component (B) is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 4 parts by mass, and still more preferably 0.9 to 1.6 parts by mass, based on 100 parts by mass of the total of the components (A) and (B). If the amount is 0.1 parts by mass or more, flatness can be ensured, and if the amount is 10 parts by mass or less, good ink-jet coatability can be ensured.

The fluorine-containing monomer as the component (E) may have a fluorine atom number of 1 or more, for example, 2 or more, preferably 3 or more. The upper limit of the number of fluorine atoms in the fluorine-containing monomer is not particularly limited, and may be, for example, 40 or less, and preferably 30 or less.

The content of fluorine atoms with respect to the total amount of the fluorine-containing monomer may be, for example, 1 mass% or more, preferably 2 mass% or more, and more preferably 5 mass% or more. The content of fluorine atoms may be, for example, 75% by mass or less, preferably 70% by mass or less, and more preferably 65% by mass or less, based on the total amount of the fluorine-containing monomer. The content of fluorine atoms in the composition of the embodiment containing the component (E) is preferably 0.01 to 10% by mass, and more preferably 0.1 to 5% by mass. When the fluorine atom content is within the above range, the effect of improving the flatness can be exhibited.

The number of (meth) acryloyl groups of the fluorine-containing monomer may be 1 or more. The number of (meth) acryloyl groups of the fluorine-containing monomer may be 1 from the viewpoint of easiness of obtaining a cured product having a low glass transition temperature. In addition, the number of (meth) acryloyl groups of the fluorine-containing monomer may be 2 or more, from the viewpoint of easily obtaining a cured product having a high glass transition temperature. The upper limit of the number of (meth) acryloyl groups of the fluorine-containing monomer is not particularly limited, and may be, for example, 4 or less, and is preferably 3 or less, and more preferably 2 or less, from the viewpoint of easily obtaining a cured product having excellent flexibility.

As a specific example of the fluorine-containing monomer, a compound represented by the following formula (E-1) can be mentioned.

Formula (E-1)

In the formula (E-1), R¹Represents a hydrogen atom or a methyl group. Furthermore, R²Represents a fluoroalkyl group, or a group in which an oxygen atom is inserted into a part of a carbon-carbon bond and a carbon-hydrogen bond of the fluoroalkyl group.

The fluoroalkyl group may be a group in which a part or all of the hydrogen atoms of the alkyl group are substituted with fluorine atoms. The number of carbon atoms of the fluoroalkyl group is not particularly limited, and may be, for example, 1 or more, and preferably 2 or more. The number of carbon atoms of the fluoroalkyl group may be, for example, 25 or less, or 20 or less.

As the fluoroalkyl group, a fluorinated alkyl group containing difluoromethylene (-CF) can be suitably used₂-) of (a) a group of (b).

Specific examples of fluoroalkyl groups include: difluoromethyl, trifluoromethyl, 1, 1-difluoroethyl, 2, 2-difluoroethyl, 1,1, 1-trifluoroethyl, 2,2, 2-trifluoroethyl, perfluoroethyl, 1,1,2, 2-tetrafluoropropyl, 1,1,1,2, 2-pentafluoropropyl, 1,1,2,2,3, 3-hexafluoropropyl, perfluoropropyl, perfluoroethylmethyl, 1- (trifluoromethyl) -1,2,2, 2-tetrafluoroethyl, 2,2,3, 3-tetrafluoropropyl, perfluoropropyl, 1,1,2, 2-tetrafluorobutyl, 1,1,2,2,3, 3-hexafluorobutyl, 1,1,1,2,2,3, 3-heptafluorobutyl, 1,1,2,2,3,3,4, 4-octafluorobutyl, perfluorobutyl, 1, 1-bis (trifluoromethyl) methyl-2, 2, 2-trifluoroethyl group, 2- (perfluoropropyl) ethyl group, 1,2,2,3,3,4, 4-octafluoropentyl group, 2,2,3,3,4,4,5, 5-octafluoropentyl group, perfluoropentyl group, 1,2,2,3,3,4,4,5, 5-decafluoropentyl group, 1-bis (trifluoromethyl) -2,2,3,3, 3-pentafluoropropyl group, 2- (perfluorobutyl) ethyl, 1,1,1,2,2,3,3,4, 4-nonafluoropentyl, 1,1,2,2,3,3,4,4,5, 5-decafluorohexyl, 1,1,2,2,3,3,4,4,5,5,6, 6-dodecafluorohexyl, perfluorohexyl, perfluoropentylmethyl, perfluorohexyl and the like.

A group in which an oxygen atom is inserted into a carbon-carbon bond or a part of a carbon-hydrogen bond of a fluoroalkyl group (hereinafter, also referred to as R)²An oxygen-containing group of (a). ) The oxygen atom may be inserted at one position or at two or more positions.

If an oxygen atom is inserted into a carbon-carbon bond, an ether bond is formed. Furthermore, if an oxygen atom is inserted into a carbon-hydrogen bond, a hydroxyl group is formed. Namely, R²The oxygen-containing group of (b) may be said to be a group containing at least one selected from the group consisting of an ether bond and a hydroxyl group.

As R²Specific examples of the oxygen-containing group of (2) include groups represented by the following formulae.

The fluorine atom content in the compound represented by the formula (E-1) may be, for example, 5% by mass or more, preferably 15% by mass or more, and more preferably 30% by mass or more. The fluorine atom content in the compound represented by the formula (E-1) may be, for example, 75% by mass or less, preferably 70% by mass or less, and more preferably 65% by mass or less.

As a specific example of the compound represented by the formula (E-1), for example, a compound represented by the following formula (E-1-1) can be mentioned.

Formula (E-1-1)

In the formula (E-1-1), R¹Represents a hydrogen atom or a methyl group, R²¹Represents a hydrogen atom or a fluorine atom, and n represents an integer of 1 or more. Multiple existence of R²¹May be the same or different from each other. Wherein R is²¹At least one of which is a fluorine atom.

n may be 1 or more, preferably 2 or more. The upper limit of n is not particularly limited, and may be, for example, 25 or less, or 20 or less.

R²¹Plural in the formula (E-1-1), at least one of which is a fluorine atom. Furthermore, R is preferred²¹More preferably 3 or more are fluorine atoms. R²¹May be all fluorine atoms.

Number of fluorine atoms relative to R²¹The total amount of (a) may be, for example, 4% or more, preferably 8% or more, and more preferably 12% or more. The proportion may be, for example, 100% or less, preferably 80% or less, and more preferably 75% or less.

As the compound represented by the formula (E-1-1), a 2-valent group (-C (R) in parentheses denoted by n is preferred²¹)₂-) is difluoromethylene (-CF₂-)。

As another specific example of the fluorine-containing monomer, a compound represented by the following formula (E-2) can be mentioned.

Formula (E-2)

In the formula (E-2), R³Represents a hydrogen atom or a methyl group. Furthermore, R⁴Represents a fluoroalkanediyl group or a group in which an oxygen atom is inserted into a part of a carbon-carbon bond and a carbon-hydrogen bond of the fluoroalkanediyl group. Multiple existence of R³May be the same or different from each other.

The fluoroalkanediyl group may be said to be a group in which a part or all of hydrogen atoms of the alkanediyl group are substituted with fluorine atoms. The number of carbon atoms of the fluoroalkanediyl group is not particularly limited, and may be, for example, 1 or more, preferably 2 or more, more preferably 3 or more, and further preferably 4 or more. The number of carbon atoms of the fluoroalkanediyl group may be, for example, 17 or less, preferably 12 or less, and more preferably 10 or less.

As the fluoroalkanediyl group, a compound containing difluoromethylene (-CF) can be suitably used₂-) of (a) a group of (b).

Specific examples of fluoroalkanediyl groups include: a linear or branched fluoroalkanediyl group having 1 to 17 carbon atoms (for example, 2,3,3,4,4,5,5,6,6,7,7,8,8,9, 9-hexadecafluoro-1, 10-decanediyl group), a fluorocycloalkanediyl group having 1 to 17 carbon atoms, and the like.

A group having an oxygen atom inserted into a part of a carbon-carbon bond and a carbon-hydrogen bond of a fluoroalkanediyl group (hereinafter also referred to as R)⁴An oxygen-containing group of (a). ) The oxygen atom may be inserted at one position or at two or more positions.

If an oxygen atom is inserted into a carbon-carbon bond, an ether bond is formed. Furthermore, if oxygen atoms are insertedInto carbon-hydrogen bonds, hydroxyl groups are formed. Namely, R⁴The oxygen-containing group of (b) may be said to be a group containing at least one selected from the group consisting of an ether bond and a hydroxyl group.

As R⁴Specific examples of the oxygen-containing group of (2) include groups represented by the following formulae.

The fluorine atom content in the compound represented by the formula (E-2) may be, for example, 4% by mass or more, preferably 8% by mass or more, and more preferably 12% by mass or more. The fluorine atom content in the compound represented by the formula (E-2) may be, for example, 90% by mass or less, preferably 75% by mass or less, and more preferably 65% by mass or less.

As a specific example of the compound represented by the formula (E-2), for example, a compound represented by the following formula (E-2-1) can be mentioned.

Formula (E-2-1)

In the formula (E-2-1), R³Represents a hydrogen atom or a methyl group, R⁴¹Represents a hydrogen atom or a fluorine atom, and m represents an integer of 1 or more. Multiple existence of R⁴¹May be the same or different from each other. Multiple existence of R³May be the same or different from each other. Wherein R is⁴¹At least one of which is a fluorine atom.

m may be 1 or more, preferably 2 or more, more preferably 3 or more, and further preferably 4 or more. The upper limit of m is not particularly limited, and may be, for example, 20 or less, preferably 17 or less, and more preferably 15 or less.

R⁴¹Plural in the formula (E-2-1), and at least one thereof is a fluorine atom. Furthermore, R is preferred⁴¹More preferably 4 or more are fluorine atoms. R⁴¹May be all fluorine atoms.

Number of fluorine atoms relative to R⁴¹Total number of (2)The ratio of (b) may be, for example, 1% or more, preferably 5% or more, and more preferably 10% or more. The proportion may be, for example, 100% or less, preferably 95% or less, and more preferably 90% or less.

As the compound represented by the formula (E-2-1), a group having a valence of 2 (-C (R) in parentheses denoted by m is preferred⁴¹)₂-) is difluoromethylene (-CF₂-)。

As another specific example of the fluorine-containing monomer, a compound represented by the following formula (E-3) can be mentioned.

Formula (E-3)

In the formula (E-3), R⁵Represents a hydrogen atom or a methyl group. Furthermore, R⁶Represents a single bond, an alkanediyl group, a fluoroalkanediyl group, or a group having an oxygen atom inserted into a carbon-carbon bond and a part of a carbon-hydrogen bond of an alkanediyl group or a fluoroalkanediyl group. Further, Ar¹Represents a fluorinated aryl group.

In addition, "R" is⁶Denotes a single bond "means Ar¹Bonded directly to an oxygen atom.

As Ar¹Preferably, the fluorinated aryl group of (a) is a fluorinated phenyl group. The fluorinated phenyl group can be said to be a group in which 1 to 5 hydrogen atoms in the phenyl group are substituted with fluorine atoms. The fluorophenyl group may have 1 or more fluorine atoms, or may have 5 fluorine atoms.

R⁶The number of carbon atoms of the alkanediyl group(s) is not particularly limited, and may be, for example, 1 or more. Furthermore, R⁶The number of carbon atoms of the alkanediyl group(s) in (e) may be, for example, 17 or less, preferably 15 or less, and more preferably 12 or less.

Specific examples of the alkanediyl group include: straight-chain or branched alkanediyl having 1 to 17 carbon atoms (e.g., methylene, ethylene, etc.), cycloalkanediyl having 1 to 17 carbon atoms, and the like.

R⁶The fluoroalkanediyl group of (A) is a compound wherein a part or all of the hydrogen atoms of the above-mentioned alkanediyl group are replaced by fluorine atomsA group. R⁶The number of carbon atoms of the fluoroalkanediyl group (b) is not particularly limited, and may be, for example, 1 or more. Furthermore, R⁶The number of carbon atoms of the fluoroalkanediyl group (b) may be, for example, 17 or less, preferably 15 or less, and more preferably 12 or less.

As R⁶The fluoroalkanediyl group of (1) may be suitably used containing difluoromethylene (-CF)₂-) of (a) a group of (b).

A group having an oxygen atom inserted into a part of a carbon-carbon bond and a carbon-hydrogen bond of an alkanediyl or fluoroalkanediyl group (hereinafter also referred to as R)⁶An oxygen-containing group of (a). ) The oxygen atom may be inserted at one position or at two or more positions.

If an oxygen atom is inserted into a carbon-carbon bond, an ether bond is formed. Furthermore, if an oxygen atom is inserted into a carbon-hydrogen bond, a hydroxyl group is formed. Namely, R⁶The oxygen-containing group of (b) may be said to be a group containing at least one selected from the group consisting of an ether bond and a hydroxyl group.

As R⁶Specific examples of the oxygen-containing group of (3) include, for example, a group containing-CH₂CH₂The group of O-, etc.

The fluorine atom content in the compound represented by the formula (E-3) may be, for example, 3% by mass or more, preferably 7% by mass or more, and more preferably 15% by mass or more. The fluorine atom content in the compound represented by the formula (E-3) may be, for example, 90% by mass or less, preferably 80% by mass or less, and more preferably 70% by mass or less.

As a specific example of the compound represented by the formula (E-3), for example, a compound represented by the following formula (E-3-1) can be mentioned.

Formula (E-3-1)

In the formula (E-3-1), R⁵Represents a hydrogen atom or a methyl group, R⁶¹Represents a hydrogen atom or a fluorine atom, R⁶²Represents a hydrogen atom or a fluorine atom, and p represents an integer of 0 or more. When p is 1 or more, a plurality thereof are presentR of (A) to (B)⁶¹May be the same or different from each other. In addition, a plurality of R's present⁶²May be the same or different from each other. Wherein R is⁶²At least one of which is a fluorine atom.

p represents an integer of 0 or more. Here, p is 0, which means that a benzene ring is directly bonded to an oxygen atom. p may be an integer of 1 or more. The upper limit of p is not particularly limited, and may be, for example, 17 or less, preferably 15 or less, and more preferably 12 or less.

R is present in the formula (E-3-1)⁶¹When (i.e. when p is an integer of 1 or more), R⁶¹All of the hydrogen atoms and all of the fluorine atoms may be used, or a part of the hydrogen atoms and the rest of the fluorine atoms may be used.

R⁶²Plural in the formula (E-3-1), at least one of which is a fluorine atom. In addition, may be R⁶²2 or more of (2) are fluorine atoms, and 3 or more may be fluorine atoms. In addition, may be R⁶²All (5) of (a) are fluorine atoms.

Number of fluorine atoms relative to R⁶¹And R⁶²The proportion of (b) may be, for example, 5% or more, preferably 10% or more, and more preferably 20% or more. The proportion may be, for example, 100% or less, preferably 95% or less, and more preferably 80% or less.

Among the fluorine-containing monomers, from the viewpoint of low moisture permeability and inkjet coatability, one or more selected from the group consisting of 2,2,3,3,4,4,5,5,6,6,7,7,8,8,9, 9-hexadecafluoro-1, 10-decanediol di (meth) acrylate, 1H, 5H-octafluoropentyl (meth) acrylate and 1H, 2H-tridecafluorooctyl (meth) acrylate are preferable.

The glass transition temperature of the cured product obtained from the composition of the present embodiment is preferably 65 ℃ to 120 ℃, more preferably 65 ℃ to 110 ℃, and most preferably 70 ℃ to 100 ℃ in view of the reliability of the organic EL device. If the glass transition temperature of the cured product is in the range of 65 ℃ to 120 ℃, stress relaxation occurs when the inorganic passivation film is formed on the cured product of the composition of the present embodiment by a method such as CVD, and the inorganic film and the OLED element are not easily peeled, so that the reliability of the organic EL element is improved.

The method for measuring the glass transition temperature of the cured product obtained from the composition of the present embodiment is not particularly limited, and measurement by a known method such as DSC or dynamic viscoelastometer is preferably performed using a dynamic viscoelastometer. The dynamic viscoelastometer can apply stress and strain to the cured product at a constant temperature rise rate, and the temperature at the peak top of the loss tangent (hereinafter abbreviated as tan δ) can be used as the glass transition temperature. When the peak of tan. delta. does not appear even when the temperature is raised from a sufficiently low temperature of about-150 ℃ to a certain temperature (Ta ℃), the glass transition temperature is considered to be-150 ℃ or lower or at least a certain temperature (Ta ℃), and a composition having a glass transition temperature of-150 ℃ or lower is not considered due to its structure, and therefore, can be considered to be at least a certain temperature (Ta ℃).

The composition of the present embodiment may use (D) an antioxidant for the purpose of improving storage stability. Examples of the antioxidant include: methylhydroquinone, hydroquinone, octadecyl-3- [3, 5-di-tert-butyl-4-hydroxyphenyl ] propionate, 2-methylene-bis (4-methyl-6-tert-butylphenol), catechol, hydroquinone monomethyl ether, mono-tert-butylhydroquinone, 2, 5-di-tert-butylhydroquinone, p-benzoquinone, 2, 5-diphenyl-p-benzoquinone, 2, 5-di-tert-butyl-p-benzoquinone, picric acid, citric acid, phenothiazine, tert-butylcatechol, 2-butyl-4-hydroxyanisole, 2, 6-di-tert-butyl-p-cresol, and the like. The antioxidant is preferably a combination of 2 or more. Among these, phenol antioxidants are preferable in terms of their great effects such as transparency and storage stability. Among the phenolic antioxidants, hindered phenolic antioxidants are preferred. The hindered phenol-based antioxidant is preferably at least 1 member of the group consisting of octadecyl 3- [3, 5-di-tert-butyl-4-hydroxyphenyl ] propionate and 2, 2-methylene-bis (4-methyl-6-tert-butylphenol), and more preferably contains octadecyl 3- [3, 5-di-tert-butyl-4-hydroxyphenyl ] propionate and 2, 2-methylene-bis (4-methyl-6-tert-butylphenol). Examples of the octadecyl 3- [3, 5-di-tert-butyl-4-hydroxyphenyl ] propionate include "Irganox 1076" manufactured by BASF Japan Ltd. Examples of 2, 2-methylene-bis (4-methyl-6-tert-butylphenol) include "SUMILIZER MDP-S" manufactured by Sumitomo chemical Co., Ltd. In the case of containing octadecyl 3- [3, 5-di-tert-butyl-4-hydroxyphenyl ] propionate and 2, 2-methylene-bis (4-methyl-6-tert-butylphenol), the content ratio of octadecyl 3- [3, 5-di-tert-butyl-4-hydroxyphenyl ] propionate to 2, 2-methylene-bis (4-methyl-6-tert-butylphenol) was such that the total of octadecyl 3- [3, 5-di-tert-butyl-4-hydroxyphenyl ] propionate and 2, 2-methylene-bis (4-methyl-6-tert-butylphenol) was 100 parts by mass, octadecyl 3- [3, 5-di-tert-butyl-4-hydroxyphenyl ] propionate is preferred in terms of mass ratio: 2, 2-methylene-bis (4-methyl-6-tert-butylphenol) ═ 10 to 90: 90-10, more preferably 25-75: 75-25.

The content of the antioxidant is preferably 0.001 to 3 parts by mass, more preferably 0.01 to 2 parts by mass, based on 100 parts by mass of the total of the components (A) and (B). When the amount is 0.001 parts by mass or more, the storage stability can be secured, and when the amount is 3 parts by mass or less, good adhesiveness can be obtained and no uncured state occurs.

The composition of the present embodiment may further contain additives used in the art, and may contain, for example, an antioxidant, a metal deactivator, a filler, a stabilizer, a neutralizer, a lubricant, an antimicrobial agent, and the like.

The composition of the present embodiment can be used as a resin composition. The composition of the present embodiment can be used as a photocurable resin composition. The composition of the present embodiment can be used as a sealing agent for an organic EL display element.

Examples of the method of curing the composition by irradiation with visible light or ultraviolet light include a method of curing the composition by irradiation with at least one of visible light or ultraviolet light. As an energy irradiation source for irradiating such visible light or ultraviolet light, there are exemplified: deuterium lamp, high-pressure mercury lamp, ultra-high pressure mercury lamp, low-pressure mercury lamp, xenon-mercury mixed lamp, halogen lamp, excimer lamp, indium lamp, thallium lamp, LED lamp, electrodeless discharge lamp, etc. In terms of the resistance to damage to the organic EL element, the composition of the present embodiment is preferably cured at a wavelength of 380nm or more, more preferably at a wavelength of 395nm or more, and most preferably at a wavelength of 395 nm. The wavelength of the energy radiation source is preferably 500nm or less because the temperature of the irradiation portion is increased by emitting infrared light, which may damage the organic EL element. As the energy irradiation source, an LED lamp emitting light of a single wavelength is preferable.

When the composition is cured by irradiation with visible light or ultraviolet light, it is preferable to irradiate the composition with 100 to 8000mJ/cm at a wavelength of 395nm²The energy ray of (2) is cured. If the concentration is 100 to 8000mJ/cm²The composition is cured and sufficient adhesive strength can be obtained. If it is 100mJ/cm²When the above is satisfied, the composition is sufficiently cured, and if it is 8000mJ/cm²Hereinafter, the organic EL element is not damaged. The energy for curing the composition is more preferably 300 to 2000mJ/cm²。

Regarding the transparency of the composition of the present embodiment, when the thickness of the organic film is 1 μm or more and 10 μm or less, the spectral transmittance in the ultraviolet-visible light region of 360nm or more and 800nm or less is preferably 95% or more, more preferably 97% or more, and most preferably 99% or more. If the content is 95% or more, an organic EL device having excellent brightness and contrast can be provided.

The inorganic/organic laminate is preferably used as the inorganic/organic laminate in 1 group, and the number of the sealing layers formed from the composition of the present embodiment is preferably 1 to 5 groups. This is because, when the inorganic/organic laminate is 6 or more groups, the sealing effect on the organic EL element is substantially the same as that in the case of 5 groups. The inorganic film of the inorganic/organic laminate preferably has a thickness of 50nm to 1 μm. The thickness of the organic film of the inorganic/organic laminate is preferably 1 to 15 μm, and more preferably 3 to 10 μm. If the thickness of the organic film is less than 1 μm, particles generated during the formation of the device may not be completely covered, and it may be difficult to apply the inorganic film with good flatness. If the thickness of the organic film exceeds 15 μm, moisture may enter from the side surface of the organic film, and the reliability of the organic EL element may be lowered.

The package substrate is formed by covering the entire upper surface of the uppermost organic film of the package layer. Examples of the package substrate include the above-described substrate. Among these, a substrate transparent to visible light is preferable. Among the substrates transparent to visible light (transparent package substrates), 1 or more of the group consisting of glass substrates and plastic substrates are preferable, and glass substrates are more preferable.

The thickness of the transparent sealing substrate is preferably 1 μm or more and 1mm or less, more preferably 10 μm or more and 800 μm or less, and most preferably 50 μm or more and 300 μm or less. By providing the transparent sealing substrate on the upper layer of the sealing layer, deterioration of the surface of the uppermost organic film when it comes into contact with gas can be suppressed, and the barrier property of the organic EL device can be improved.

Next, a method for manufacturing an organic EL device having such a configuration will be described. First, an anode, an organic EL layer including a light-emitting layer, and a cathode patterned into a predetermined shape are sequentially formed on a 1 st substrate by a conventionally known method, thereby forming an organic EL element. For example, when an organic EL device is used as a dot matrix display device, banks (banks) are formed to divide light emitting regions into an array, and an organic EL layer including a light emitting layer is formed in a region surrounded by the banks.

Next, a 1 st inorganic film having a predetermined thickness is formed on the substrate on which the organic EL element is formed by a film formation method such as a PVD (Physical Vapor Deposition) method such as a sputtering method or a CVD (Chemical Vapor Deposition) method such as a plasma CVD (Chemical Vapor Deposition) method. Then, the composition of the present embodiment is attached to the 1 st inorganic film by a coating film forming method such as a solution coating method or a spray coating method, a flash evaporation method, an ink jet method, or the like. Among these, the inkjet method is preferable in terms of productivity. Then, the composition is cured by irradiation with ultraviolet rays, electron beams, or energy rays such as plasma, thereby forming a 1 st organic film. Through the above procedure, 1 set of inorganic/organic laminates was formed. The curing rate of the composition is not particularly limited as long as the effects of the present embodiment can be exhibited, and for example, a value obtained by a measurement method described later may be 90% or more, preferably 95% or more.

The above-described steps of forming the inorganic/organic laminate are repeated only a predetermined number of times. The inorganic/organic laminate of the final group, i.e., the uppermost layer, may be subjected to surface planarization by the coating method, the flash evaporation method, the ink jet method, or the like.

Next, a transparent sealing substrate was bonded to the surface of the substrate to which the composition was attached. And carrying out position alignment during fitting. Then, the composition of the present embodiment present between the inorganic film of the uppermost layer and the transparent encapsulating substrate is cured by irradiation with an energy ray from the transparent encapsulating substrate side. Thereby, the composition is cured to form the uppermost organic film, and the uppermost organic film is bonded to the transparent sealing substrate. In this way, the method of manufacturing the organic EL device is completed.

After the composition is attached to the inorganic film, it may be polymerized by local irradiation with energy rays. In this way, the shape of the composition forming the uppermost organic film can be prevented from being distorted when the transparent sealing substrate is mounted. The thicknesses of the inorganic film and the organic film may be the same for each inorganic/organic laminate or may be different for each inorganic/organic laminate.

The above description has been given taking as an example a top emission type organic EL device. The present embodiment can also be applied to a bottom emission type organic EL device that emits light generated in an organic EL layer from the substrate side.

The organic EL element of the present embodiment can be used as a planar light source, a segment display device, or a dot matrix display device.

According to this embodiment, since the sealing layer for blocking the organic EL element formed on the 1 st substrate from the outside air is formed and the transparent sealing substrate is further disposed on the sealing layer, a sealing structure having a sufficient barrier property against water vapor and oxygen for the organic EL element can be obtained. According to the embodiment of the present embodiment, a package structure having sufficient adhesive strength between the transparent package substrate and the package layer can be obtained.

According to the present embodiment, after the composition of the present embodiment constituting the uppermost organic film of the sealing layer is adhered, the transparent sealing substrate can be placed without curing the composition, and then the composition is cured, so that the sealing layer and the transparent sealing substrate can be bonded to each other while the uppermost organic film constituting the sealing layer is formed. As a result, this embodiment has an effect of simplifying the process as compared with the case where the sealing layer and the transparent sealing substrate are bonded with an adhesive.

The composition of the present embodiment is preferably a composition according to JIS Z0208: 1976 the moisture permeability of the cured product at 100 μm thickness measured by exposing the cured product to 85 deg.C and 85% RH for 24 hours is 350g/m²The following. If the above moisture permeability exceeds 350g/m²Moisture may reach the organic light emitting material layer to cause dark spots.

According to the present embodiment, the sealing agent for an organic EL display element can be easily applied by an inkjet method, and is excellent in reliability of an OLED element, transparency of a cured product, and barrier properties. According to the present embodiment, a method for manufacturing an organic EL display element using an encapsulant for an organic EL display element can be provided. The ink jet method is a method of ejecting fine droplets from a nozzle to apply the droplets to an object in a non-contact manner.

Examples

(Experimental examples 1 to 8)

Compositions were prepared and evaluated by the following methods.

(preparation of composition)

The materials used in Table 1 were used. The materials used were mixed in the compositions shown in tables 2 to 3 to prepare compositions. Using the obtained composition, evaluation of E-type viscosity, surface tension, moisture permeability, expansion ratio of coated area, curing ratio, flatness, transparency, glass transition temperature, and organic EL were performed by the following evaluation methods. The results are shown in tables 2 to 3. The composition names in tables 2 to 3 are abbreviated as shown in Table 1. The fluorine atom contents shown in tables 2 to 3 are calculated from the compositions and are shown based on the total amount of the composition.

[ E type viscosity η ]

The viscosity of the composition was measured using an E-type viscometer (cone plate type: cone angle 1 ℃ 34', radius of cone rotor 24mm) at a temperature of 25 ℃ and a rotation speed of 100 rpm.

[ surface tension γ ]

The surface tension of the composition was measured by the pendant drop method using a contact angle meter (DM 500, manufactured by synghobis interface science) under an atmosphere of 23 ℃.

[ photocuring conditions ]

In evaluating the cured physical properties of the composition, the composition was cured under the following light irradiation conditions. The cumulative quantity of LIGHT at 395nm was 1500mJ/cm using an LED lamp emitting a 395nm wavelength (UV-LED LIGHT SOURCE H-4MLH200-V1 manufactured by HOYA Co., Ltd.)²The composition is photocured under the conditions of (1) to obtain a cured product.

[ moisture permeability ]

A sheet-like cured product having a thickness of 0.1mm was produced under the above-mentioned photocuring conditions, and the thickness was measured in accordance with JIS Z0208: 1976 "method for testing moisture permeability of moisture-proof packaging Material (cup method)", calcium chloride (anhydrous) was used as a moisture absorbent, and the measurement was carried out under the conditions of an atmospheric temperature of 85 ℃ and a relative humidity of 85%.

[ curing Rate ]

The composition obtained in each experimental example was applied to the alkali-free glass cleaned by the above method to a size of 10mm × 10mm so as to have a thickness of 10 μm using the above ink jet device, and cured under the above photocuring conditions in a nitrogen atmosphere having an oxygen concentration of less than 0.1%, and the curing rate was measured by the following procedure.

The cured composition and the composition before curing were subjected to an infrared spectrometer (manufactured by Thermoscientific, Nicolet is5, DTGS Detector, resolution 4 cm)^-1) Infrared light is made incident on the measurement sample to measure an infrared spectroscopic spectrum. In the obtained infrared spectroscopic spectrum, the peak change was not generated before and after curing at 2950cm^-1The stretching vibration peak of the carbon-hydrogen bond of methylene observed nearby was used as an internal standard, and 810cm was obtained from the peak area before and after curing of the internal standard and the peak of the out-of-plane bending vibration of the carbon-hydrogen bond bonded to the carbon-carbon double bond belonging to the (meth) acrylate^-1The area of the near peak before and after curing was calculated as the curing ratio using the following equation.

Curing ratio (%) [1- (Ax/Bx)/(Ao/Bo) ] × 100

In this case, the amount of the solvent to be used,

ao: represents 810cm^-1Area of peak before curing in the vicinity.

Ax: represents 810cm^-1Area of peak after curing in the vicinity.

And (4) Bo: denotes 2950cm^-1Area of peak before curing in the vicinity.

Bx: represents 2950cm-¹Area of peak after curing in the vicinity.

[ transparency ]

The compositions obtained in the respective experimental examples were formed to a thickness of 10 μm between 2 pieces of 25mm × 25mm × 1mmt (mm thick) glass plate (alkali-free glass, Eagle XG manufactured by Corning Inc.) 2, and the irradiation dose was 1500mJ/cm by using an LED lamp²The ultraviolet ray having a wavelength of 395nm was irradiated and cured to obtain a cured product. The obtained cured product was measured for transparency by measuring the spectral transmittances at 380nm, 412nm and 800nm with an ultraviolet-visible spectrophotometer ("UV-2550" manufactured by Shimadzu corporation).

[ glass transition temperature ]

The composition obtained in each experimental example was sandwiched between PET films using a silicon wafer having a thickness of 1mm as a mold frame. The composition was cured from the top surface under the photocuring conditions, and then cured from below under the photocuring conditions to prepare a cured product of the composition having a thickness of 1 mm. The resulting cured product was cut into a length of 50mm and a width of 5mm by a cutter to obtain a cured product for measuring glass transition temperature. The obtained cured product was subjected to stress and strain in the tensile direction of 1Hz in a nitrogen atmosphere by a dynamic viscoelasticity measuring apparatus "DMS 210" manufactured by Seiko Instruments inc, and tan δ was measured while increasing the temperature from-150 ℃ to 200 ℃ at a rate of 2 ℃ per minute, and the temperature of the peak top of tan δ was defined as the glass transition temperature. the peak top of tan δ is the maximum value in the region where tan δ is 0.3 or more. In the case where tan δ is 0.3 or less in the region of-150 ℃ to 200 ℃, the glass transition temperature is considered to be more than 200 ℃ (200<), if the peak top of tan δ exceeds 200 ℃.

[ expansion ratio of coating area ]

The composition obtained in each experimental example was pattern-coated on a substrate (alkali-free glass (Eagle XG, manufactured by corning inc.) having a thickness of 70mm × 70mm × 0.7 mmt) so as to form 4mm × 4mm × 10 μmt of × μmt using an inkjet ejection apparatus (MID 500B, manufactured by Musashi Engineering, inc.) the alkali-free glass was cleaned with acetone and isopropanol, respectively, and then cleaned for 5 minutes using a UV ozone cleaning apparatus UV-208 manufactured by technoviion, inc.

(expansion ratio of coating area) ((contact area of composition in contact with substrate surface after 5 minutes from pattern coating)/(contact area of composition in contact with substrate surface immediately after completion of pattern coating)) × 100 (%)

[ flatness ]

The substrate (alkali-free glass (EagleXG, manufactured by Corning inc.)) of 70mm × 70mm × 0.7.7 mmt was etched to form 25 μm × 25 μm × 3 μm depressions, which were arranged at intervals of 10 μm in the front, rear, left, and right directions, and the substrate was cleaned with acetone and isopropyl alcohol, and then cleaned for 5 minutes with a UV-208 cleaning apparatus manufactured by Technovision, inc., then a 200nm SiN film was formed on the substrate provided with the depressions by a plasma CVD method, and then a sealant was pattern-coated using an inkjet ejection apparatus (midshi Engineering, manufactured by inc., MID500B, solvent-based HEAD "MID HEAD") to form 50mm × 50mm × 10 μm, and after pattern-coating, the sealant was left at 23 ℃ for 5 minutes with respect to 50%, and the shape of the sealant coating film was observed, and the flatness of the sealant coating film was found in table 1.

Flatness (%) (area of encapsulant coating film after leaving for 5 minutes)/(50 mm × 50mm)

For example, the flatness of 50% indicates that a part of the pattern-coated encapsulant is repelled, and the SiN film is exposed in a half (50%) of a range of 50mm × 50 mm.

[ evaluation of organic EL ]

[ production of organic EL element substrate ]

A30 mm square glass substrate (thickness: 700 μm) with an ITO electrode was cleaned with acetone and isopropyl alcohol, respectively. Then, the following compounds were sequentially deposited by vacuum deposition to form thin films, and a substrate having an organic EL element of 2mm square composed of an anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron injection layer, and a cathode was obtained. The composition of each layer is as follows.

ITO on the anode, thickness of the anode film 150nm

Hole injection layer 4, 4' -tris { 2-naphthyl (phenyl) amino } triphenylamine (2-TNATA)

Hole-transporting layer N, N '-diphenyl-N, N' -dinaphthylbenzidine (α -NPD)

Thickness of luminescent layer tris (8-quinolinolato) aluminum (metal complex material), thickness of luminescent layer

The light-emitting layer also functions as an electron transport layer.

Lithium fluoride of the electron-injecting layer

Thickness of cathode aluminum film 150nm

[ production of organic EL element ]

Then, a mask (mask) having an opening of 10mm × 10mm was provided so as to cover the organic EL element of 2mm × 2mm, and a SiN film was formed by a plasma CVD method, and then, the composition (organic film) obtained in each experimental example was coated at a thickness of 10 μm so as to cover the organic EL element of 2mm × 2mm in a nitrogen atmosphere using the above-mentioned ink jet apparatus, and after curing the composition under the above-mentioned photocuring conditions, a mask (mask) having an opening of 10mm × 10mm was provided so as to cover the entire cured product, and a SiN film was formed by a plasma CVD method, thereby obtaining an organic EL display element.

The thickness of the formed SiN (inorganic substance film) was about 1 μm, and then, a transparent non-substrate double-sided tape of 30mm × 30 and 30mm × 25 μmt was bonded to alkali-free glass of 30mm × 30 and × 0.7.7 mmt (Eagle XG manufactured by Corning inc.) to fabricate an organic EL device (evaluation of organic EL).

[ initially ]

The organic EL device immediately after completion of the fabrication was applied with a voltage of 6V, and the light emission state of the organic EL device was observed visually and with a microscope to measure the diameter of the dark spot.

[ durability ]

The organic EL element immediately after completion of the fabrication was exposed to 85 ℃ and 85 mass% relative humidity for 70 hours, and then a voltage of 6V was applied to observe the light emission state of the organic EL element visually and under a microscope, and the diameter of the dark spot was measured.

The diameter of the dark spot can be regarded as an index for evaluating the degree of permeation of the pin hole of the passivation layer by the sealing agent and the degree of discharge of moisture in the sealing agent in the form of an out-gassing. The diameter of the dark spots is preferably 300 μm or less, more preferably 50 μm or less, and most preferably no dark spots are evaluated.

The following was found from the above experimental examples.

The composition of the present embodiment can provide a composition excellent in reliability of an organic EL element, ejection properties by high-precision ink jet, shape retention properties after ink jet coating, and low moisture permeability.

When the acyclic alkanediol dimethacrylate having 6 or more carbon atoms is used as (a), the cyclic monofunctional (meth) acrylate and the cyclic 2-functional (meth) acrylate are used as (B), and the numerical formulae (I) to (III) are satisfied at the same time, the reliability, the inkjet ejection property, the shape retention property, and the low moisture permeability are excellent (experimental examples 1 to 3, 10 to 11).

In the case where (E) is further contained, it is understood that the surface free energy of the sealing agent is reduced by the fluorine-containing monomer and the sealing agent easily follows fine irregularities, and thus the flatness is improved (experimental examples 4 to 9).

On the other hand, when the acyclic alkanediol di (meth) acrylate having less than 6 carbon atoms was used as (a), the expansion rate of the coating area was large, and the shape after inkjet coating could not be maintained, i.e., the shape-maintaining property was problematic (experimental example 12). When the content of the component (a) exceeds 85 parts by mass and the content of the component (B) is less than 15 parts by mass, the viscosity is low, the formula (III) is not satisfied, and the shape-retaining property and reliability cannot be obtained (experimental example 13). When a long-chain alkyl monofunctional acrylate and a cyclic 2-functional methacrylate were used as (B) instead of the cyclic monofunctional (meth) acrylate, the viscosity was low and the formula (III) was not satisfied, and reliability, shape retention property, and low moisture permeability could not be obtained (experimental example 14). When acyclic alkanediol dimethacrylate having 6 or more carbon atoms was used as (a) and 2 kinds of cyclic (meth) acrylates were used as (B), and the viscosity exceeded 50mPa · s while satisfying the expressions (II) to (III), the ink jet ejection was not performed although the ink jet recording apparatus was excellent in low moisture permeability, and reliability and shape retention were not evaluated (experimental example 15). When only a cyclic monofunctional acrylate is used as (B) without using a cyclic 2-functional (meth) acrylate and the numerical formulae (I) to (III) are satisfied, the transparency and the shape retention property are poor (experimental example 16).

[ Table 1]

[ Table 2]

[ Table 3]

Industrial applicability

The composition of the present embodiment is excellent in ejection property by high-precision inkjet and flatness after inkjet application, has low moisture permeability and transparency, and does not deteriorate an organic EL element. This embodiment can perform inkjet coating in a short time. The composition of the present embodiment can be suitably used for bonding of electronic products, particularly display parts such as organic EL (for example, flexible displays or organic EL devices used in wearable products), electronic parts such as image sensors of CCD and CMOS, and element packages used in semiconductor parts. Particularly, the adhesive is suitable for bonding for sealing organic EL devices, and satisfies the characteristics required for an adhesive for sealing devices such as organic EL devices and a covering agent for sealing devices.

The composition described above is one embodiment of the present embodiment, and the encapsulant for organic EL elements, cured product, organic EL device, display, methods for producing them, and the like of the present embodiment have the same configuration and effects.

Claims

1. An encapsulant for an organic electroluminescent display element, comprising: (A) a non-cyclic alkanediol di (meth) acrylate having 6 or more carbon atoms, (B) a cyclic monomer, and (C) a photopolymerization initiator,

the encapsulant for organic electroluminescent display elements satisfies the following numerical formulae (I) and (III) at the same time:

8mPa·s≤η≤50mPa·s…(I)

γ/2η<0.9m/s…(III)

in the formula, η represents the viscosity measured at 25 ℃ with an E-type viscometer, and γ represents the static surface tension measured by the pendant drop method.

2. A sealing agent for an organic electroluminescent display element, which comprises (A) acyclic alkanediol di (meth) acrylate having 6 or more carbon atoms, (B) a cyclic monomer, and (C) a photopolymerization initiator,

the encapsulant for organic electroluminescent display elements satisfies the following numerical formulae (I), (II) and (III) at the same time:

8mPa·s≤η≤50mPa·s…(I)

14mN/m≤γ≤40mN/m…(II)

γ/2η<0.9m/s…(III)

3. The sealing agent for an organic electroluminescent display element according to claim 1 or 2, wherein the cyclic monomer (B) contains 1 or more kinds of alicyclic monomers.

4. The sealing agent for an organic electroluminescent display element according to any one of claims 1 to 3, wherein the component (E) contains a fluorine-containing monomer having a fluorine atom and a (meth) acryloyl group.

5. The sealing agent for an organic electroluminescent display element according to claim 4, wherein the fluorine atom content of the fluorine-containing monomer is 2 to 70% by mass based on the total amount of the fluorine-containing monomer.

6. The encapsulant for organic electroluminescent display elements according to claim 4 or 5, wherein the fluorine-containing monomer comprises at least one selected from the group consisting of a compound represented by formula (E-1), a compound represented by formula (E-2), and a compound represented by formula (E-3),

formula (E-1)

In the formula (E-1),

R¹represents a hydrogen atom or a methyl group,

R²represents fluoroalkyl or is fluorinatedA group having an oxygen atom inserted into a part of a carbon-carbon bond and a carbon-hydrogen bond of the alkyl group;

formula (E-2)

In the formula (E-2),

R³represents a hydrogen atom or a methyl group,

R⁴represents a fluoroalkanediyl group or a group in which an oxygen atom is inserted into a part of a carbon-carbon bond and a carbon-hydrogen bond of the fluoroalkanediyl group; multiple existence of R³Optionally identical or different from each other;

formula (E-3)

In the formula (E-3),

R⁵represents a hydrogen atom or a methyl group,

R⁶represents a single bond, an alkanediyl group, a fluoroalkanediyl group, or a group having an oxygen atom inserted into a carbon-carbon bond and a part of a carbon-hydrogen bond of an alkanediyl group or a fluoroalkanediyl group,

Ar¹represents a fluorinated aryl group.

7. The encapsulant for organic electroluminescent display elements according to claim 6, wherein the fluorine-containing monomer comprises at least one selected from the group consisting of a compound represented by formula (E-1-1), a compound represented by formula (E-2-1), and a compound represented by formula (E-3-1),

formula (E-1-1)

In the formula (E-1-1), R¹Represents a hydrogen atom or a methyl group, R²¹Represents a hydrogen atom or a fluorine atom, and n represents an integer of 1 or more; multiple existence of R²¹Optionally identical or different from each other; wherein R is²¹At least one of which is a fluorine atom;

formula (E-2-1)

In the formula (E-2-1), R³Represents a hydrogen atom or a methyl group, R⁴¹Represents a hydrogen atom or a fluorine atom, and m represents an integer of 1 or more; multiple existence of R⁴¹Optionally identical or different from each other; multiple existence of R³Optionally identical or different from each other; wherein R is⁴¹At least one of which is a fluorine atom;

formula (E-3-1)

In the formula (E-3-1), R⁵Represents a hydrogen atom or a methyl group, R⁶¹Represents a hydrogen atom or a fluorine atom, R⁶²Represents a hydrogen atom or a fluorine atom, and p represents an integer of 0 or more; multiple existence of R⁶¹Optionally identical or different from each other; multiple existence of R⁶²Optionally identical or different from each other; wherein R is⁶²At least one of which is a fluorine atom.

8. The sealing agent for an organic electroluminescent display element according to any one of claims 4 to 7, wherein the content of the component (E) is in the range of 0.1 to 10 parts by mass relative to 100 parts by mass of the total of the components (A) and (B).

9. The sealing agent for organic electroluminescent display element according to any one of claims 4 to 8, wherein the component (E) contains one or more selected from the group consisting of 2,2,3,3,4,4,5,5,6,6,7,7,8,8,9, 9-hexadecafluoro-1, 10-decanediol di (meth) acrylate, 1H, 5H-octafluoropentyl (meth) acrylate, and 1H,1H,2H, 2H-tridecafluorooctyl (meth) acrylate.

10. The sealing agent for an organic electroluminescent display element according to any one of claims 1 to 9, wherein the coating is performed by an inkjet method.

11. The encapsulant for organic electroluminescent display elements according to any one of claims 1 to 10, wherein the 2-functional (meth) acrylate oligomer, the 2-functional (meth) acrylate polymer, the polyfunctional (meth) acrylate oligomer, or the polyfunctional (meth) acrylate polymer is not contained.

12. The sealing agent for an organic electroluminescent display element according to any one of claims 1 to 11, wherein a glass transition temperature of a cured product is 65 ℃ or higher and 120 ℃ or lower.

13. The sealing agent for an organic electroluminescent display element according to any one of claims 1 to 12, wherein at least 1 of the component (B) has 2 or more cyclic structures in a molecule.

14. The sealing agent for an organic electroluminescent display element according to any one of claims 1 to 13, wherein at least 2 of the component (B) has 2 or more cyclic structures in a molecule.

15. The sealing agent for an organic electroluminescent display element according to any one of claims 1 to 14, wherein the component (B) contains 1 or more selected from the group consisting of ethoxylated o-phenylphenol (meth) acrylate, m-phenoxybenzyl (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, and ethoxylated bisphenol A di (meth) acrylate represented by the following structural formula,

wherein each R is independently a hydrogen atom or a methyl group; in the formula, m and n, m + n is 2-10.

16. The sealing agent for an organic electroluminescent display element according to any one of claims 1 to 15, wherein the component (a) is an alkanediol di (meth) acrylate having 12 or less carbon atoms.

17. The sealing agent for an organic electroluminescent display element according to any one of claims 1 to 16, wherein the component (a) contains 1 or more selected from the group consisting of 1, 9-nonanediol di (meth) acrylate, 1, 10-decanediol di (meth) acrylate, and 1, 12-dodecanediol di (meth) acrylate.

18. The encapsulant for organic electroluminescent display elements according to any one of claims 1 to 17, wherein the component (C) contains 2,4, 6-trimethylbenzoyl-diphenyl-phosphine oxide.

19. The sealing agent for an organic electroluminescent display element according to any one of claims 1 to 18, wherein the content of the component (C) is 0.5 to 4 parts by mass.

20. The sealing agent for an organic electroluminescent display element according to any one of claims 1 to 19, further comprising (D) an antioxidant.

21. The sealing agent for an organic electroluminescent display element according to claim 20, wherein the component (D) is a hindered phenol antioxidant.

22. The sealing agent for an organic electroluminescent display element according to any one of claims 20 to 21, wherein the sealing agent contains 2 or more kinds of the component (D).

23. The sealing agent for an organic electroluminescent display element according to any one of claims 1 to 22, wherein the sealing agent is cured at a wavelength of 395nm to 500 nm.

24. The encapsulant for organic electroluminescent display elements according to claim 23, wherein the encapsulant is cured with 395nm LED lamp.

25. A cured product obtained by curing the sealing agent for an organic electroluminescent display element according to any one of claims 1 to 24.

26. An organic EL device, which comprises the cured product of claim 25.

27. A display comprising the cured product according to claim 25.

28. A display having flexibility, which comprises the cured product according to claim 25.

29. An organic EL device having flexibility, which comprises the cured product according to claim 25.