JP5959274B2 - Resin composition for sealing organic electroluminescence element, organic electroluminescence element and display device using the same - Google Patents

Description

  The present invention relates to a resin composition used for sealing an organic electroluminescence device that emits light with high brightness by application of an electric field, and more specifically, an organic material formed on a substrate in order to protect the organic electroluminescence device from moisture and the like. The present invention relates to an electroluminescence element and a display device using the same.

As a light-emitting electronic display device, there is an electroluminescence display (ELD). As a constituent element of ELD, an inorganic or organic electroluminescence element (hereinafter referred to as inorganic or organic EL element) can be mentioned. Inorganic EL elements have been used as planar light sources, but an alternating high voltage is required to drive the light emitting elements. An organic EL device has a structure in which a light emitting layer containing a compound that emits light is sandwiched between a cathode and an anode, and injects electrons and holes into the light emitting layer to recombine excitons. It is an element that emits light by utilizing the emission of light (fluorescence / phosphorescence) when this exciton is deactivated, and can emit light at a voltage of several volts to several tens of volts. Therefore, it has a wide viewing angle, high visibility, and since it is a thin-film type completely solid element, it has attracted attention from the viewpoints of space saving and portability.
An organic EL element is a polycrystalline semiconductor device and can be used for a backlight of a liquid crystal because it can emit light with high luminance at a low voltage, and is expected to be a thin flat display device. However, the organic EL element is very sensitive to moisture, and the interface between the metal electrode and the organic EL layer is peeled off due to the influence of moisture, the metal is oxidized to increase resistance, or the organic matter itself is altered by moisture. For this reason, there is a disadvantage that the light is not emitted and the luminance is lowered.

  Conventionally, in an organic EL element, it is known that a hygroscopic material layer is provided on the inner surface of a sealing material in order to absorb moisture remaining inside after sealing and to absorb moisture entering from the outside. It has been. For example, from an organic EL display device (see Patent Document 1) in which an organic EL element is sealed in a sealing material and a hygroscopic agent is disposed on the inner surface of the sealing material, or an alkaline earth metal oxide It is known that a moisture absorption film is disposed on the inner side surface of the sealing material to suppress the intrusion of moisture into the organic EL element (see Patent Document 2). Furthermore, a sealing method using a film has been proposed (see Patent Documents 3 and 4).

Japanese Patent Laid-Open No. 9-148066 JP 2000-260562 A JP 2003-059645 A, Japanese Patent Application Laid-Open No. 5-101884

However, when a resin with low moisture permeability is used, the functional group of the resin is reduced, and adhesive strength with the substrate (substrate) / sealing glass cannot be obtained, and long-term reliability (non-light emitting point or light emitting surface There is a problem that display defects that do not emit light in the surroundings, so-called dark spot deterioration) cannot be maintained, and in order to further increase the water absorption, when a desiccant that is a water-absorbing particle is mixed and used in the resin ,
Due to the desiccant which is a non-adhesive substance, the adhesiveness with the substrate (substrate) and the sealing glass is further lowered, and there is a problem that sufficient adhesive strength cannot be obtained.
In addition, when a curable resin is used as such a sealing resin, the molecular mobility is lost after the resin is completely covered with the water-absorbing particles after curing. The problem of falling. Furthermore, since the volume expansion of the desiccant after water absorption cannot be mitigated, the adhesiveness with the substrate (substrate) / sealing glass is inferior due to this stress, and the above reliability cannot be maintained. It has occurred.

  Therefore, the present invention has been made to solve the above-described problems, and has good adhesion to a substrate such as a glass of a display device, and further has long-term reliability (non-light-emitting points and surroundings of light-emitting surfaces). Organic electroluminescent device sealing resin composition capable of ensuring display defects in which no light emission can be obtained, that is, deterioration due to so-called dark spots), and suppressing the occurrence of defects, and organic electroluminescent devices and displays using the same It is an object to provide an apparatus.

  As a result of intensive studies to solve the above problems, the present inventors have found that the shear bond strength with the glass after curing and moisture absorption treatment and the exothermic peak behavior in DSC are important, and to complete the present invention. It has come.

That is, the said subject of this invention was achieved by the following means.
(1) A resin composition for encapsulating an organic electroluminescence device comprising at least a curable component , a binder resin and a desiccant,
Containing 10 parts by mass or more of the desiccant with respect to 100 parts by mass of the binder resin;
After curing treatment at 100 ° C. 3 h, 85 ° C., 85% relative humidity, when the moisture absorption treatment under conditions of 24 hours, 1) I der shear bond strength than 1MPa the glass, 2) exothermic peak by DSC A resin composition for sealing an organic electroluminescence element , which can be confirmed and has a characteristic that the calorific value is 50 J / g or more .
(2) The resin composition for sealing an organic electroluminescent element according to (1), wherein the resin composition is a thermosetting type.
( 3 ) The resin composition for sealing an organic electroluminescent element according to (1) or (2) , wherein an exothermic peak temperature in the DSC can be confirmed in a range of 100 ° C to 180 ° C.
(4) The resin composition for sealing an organic electroluminescent element according to any one of claims 1 to 3, wherein the curable component is an epoxy compound or resin having an epoxy group.
(5) the curable component, an epoxy compound or resin having an epoxy group, which further comprises a phenolic curing agent (1) The organic electroluminescent according to any one of - (4) Resin composition for device sealing.
(6) The phenol-based curing agent is contained in an amount of 50 to 200 parts by mass with respect to 100 parts by mass of the epoxy compound or resin having the epoxy group, for sealing an organic electroluminescent element according to (5) Resin composition.
( 7 ) The organic electroluminescent device sealing according to any one of (1) to ( 6 ), wherein the resin composition contains a compound or resin having a skeleton of a polycyclic aromatic ring. Resin composition for stopping.
(8) The resin composition for sealing an organic electroluminescent element according to (7), wherein the compound or resin having a skeleton of a polycyclic aromatic ring is a compound or resin having a hydroxyl group and a naphthalene skeleton. object.
(9) The method according to any one of (1) to (8), further comprising at least one curing accelerator selected from tertiary amines, imidazoles, and quaternary ammonium salts. The resin composition for organic electroluminescent element sealing of description.
(10) The content of the binder resin in the resin composition is 10 to 90 parts by mass with respect to 100 parts by mass of the solid content (nonvolatile component), and any one of (1) to (9) Item 2. A resin composition for sealing an organic electroluminescent element according to item 1.
( 11 ) An organic electroluminescence device formed by sealing with the resin composition according to any one of (1) to ( 10 ).
( 12 ) The display apparatus which has an organic electroluminescent element as described in said ( 11 ).

  According to the present invention, the adhesion of the display device to a substrate such as glass is good, and long-term reliability (non-light-emitting points and display defects where light cannot be emitted around the light-emitting surface, deterioration due to so-called dark spots) can be secured. The resin composition for organic electroluminescent element sealing which can suppress generation | occurrence | production of a malfunction, an organic electroluminescent element using this, and a display apparatus can be provided.

It is a figure which shows typically the cross section of the preferable form of the adhesive film for sealing of this invention. It is a figure which shows typically the cross section of another preferable form of the organic EL element sealed with the adhesive film for sealing of this invention.

Hereinafter, embodiments of the present invention will be described in detail.
The resin composition of the present invention is a resin composition for sealing an organic electroluminescence element (organic EL element).
The organic EL element is sealed as follows.
First, a transparent electrode is formed to a thickness of about 0.1 μm on a glass or film substrate. In forming a transparent electrode, there are methods such as vacuum deposition and sputtering. However, film formation by vacuum deposition may cause crystal grains to grow and reduce the smoothness of the film surface, and when applied to a thin film EL, it needs to be taken care of because it causes a dielectric breakdown film and uneven light emission. . On the other hand, film formation by sputtering has good surface smoothness, and favorable results are obtained when a thin film device is laminated thereon. Subsequently, a hole transport layer and an organic EL layer are sequentially formed to a thickness of 0.05 μm on the transparent electrode. Further, a back electrode is formed to a thickness of 0.1 to 0.3 μm on the organic EL layer.

  The thermosetting resin composition of the present invention is transferred onto a glass or film substrate on which these elements have been formed by using a roll laminator or the like. At this time, the thermosetting resin composition of the present invention is previously formed on a base film (release film) and formed into a film shape, and the thermosetting composition formed in this film shape is formed with a roll laminator. Transcript. Next, a water-impermeable glass or film substrate is superimposed on the transferred thermosetting resin composition. This is heat-pressed using a vacuum laminator to temporarily fix the upper and lower substrates. Then, it heats and hardens a thermosetting resin at the temperature of this heating process. In addition, as for the temperature of the heat curing in this heating process, it is desirable to carry out at 120 degrees C or less so that an organic EL element may not be damaged.

<Resin composition and adhesive layer>
The resin composition of the present invention, least hardening component also includes a binder resin and a drying agent, the resin composition after curing treatment at 100 ° C. 3 h, 85 ° C., 85% relative humidity, for 24 hours If moisture absorption treatment under the conditions, 1) shear bond strength between the glass I der least 1 MPa, 2) exothermic peak in DSC to check, and heating value and has a characteristic is 50 J / g or more .

The shear bond strength with glass is 1 MPa or more.
The shear bond strength with glass can be measured as follows.
An organic EL element sandwiched between glass sealing substrates is prepared as shown in the Examples, and a portion where the organic EL layer does not exist (referred to as a bezel) is used to measure the shear adhesive strength with glass.
The bezel part of the organic EL element is cut into 5 mm length × 5 mm width, and this is treated for 24 hours under conditions of 85 ° C. and 85% relative humidity, and then using a universal bond tester (for example, DAGE series 4000). Measure the shear adhesive strength at a stage temperature of 25 ° C. with glass, head height: adhesive thickness + 5 μm, speed 50 μm / sec.

Alternatively, since the production of the organic EL element requires cost and time, the shear bond strength with glass is measured by the following method.
The release film on the side to be bonded to the organic EL element side of the adhesive film having release sheets on both sides of the prepared adhesive layer is peeled off and bonded to 5 mm square glass while heating at 60 ° C., and then the sealing substrate is attached. The release sheet of the adhesive layer on the side to be bonded was peeled off and pressure-bonded to 12 mm square glass at 60 ° C./500 gf / 3 s, and the sample thus produced was heated and cured in a heating furnace at 100 ° C. for 3 hours. Thereafter, a sample laminated with glass / adhesive film / glass is prepared, and the shear adhesive strength with the glass is measured.
A sample laminated with glass / adhesive film / glass prepared as described above was treated for 24 hours under the conditions of 85 ° C. and 85% relative humidity, and then a universal bond tester (for example, DAGE series 4000) was used. Then, the shear adhesive strength with glass at a stage temperature of 25 ° C., head height: adhesive thickness + 5 μm, and speed of 50 μm / sec is measured.

The resin composition of the present invention, after curing treatment under the conditions described above, although the exothermic peak by DSC in which it can be confirmed, this exothermic peak is not preferable to be able to check the range of 100 ° C. to 180 ° C.. Further, the heating value of the exothermic peak (crystallization heat) is rather preferably is 50 J / g or more, in the present invention, it is 50 J / g or more. The calorific value is preferably 50 J / g or more and 800 J / g or less, and more preferably 100 J / g or more and 500 J / g or less.
The DSC exothermic peak and calorific value are measured as follows.
A resin composition (each sealant) was collected from the organic EL device produced by measuring the shear adhesive strength, and treated for 24 hours under the conditions of 85 ° C. and 85% relative humidity. Using an apparatus (for example, EXSTAR DSC7020 manufactured by SII Nano Technology Co., Ltd.), the sample is heated in air to 300 ° C. at a heating rate of 10 ° C./min, and the calorific value is measured. The reference uses alumina.

The resin composition of the present invention is a curable resin composition, and it is preferable from the viewpoint of handleability that an adhesive film is obtained by semi-curing the resin composition.
That is, a film-like adhesive layer made of a resin composition is formed, and it is more preferable from the viewpoint of handleability to temporarily attach a release film to both sides or one side of the adhesive layer.

For this reason, hereinafter, the resin composition will be described as an adhesive layer.
As an adhesive bond layer, it consists of what contains a sclerosing | hardenable component. The adhesive layer may be one layer or two or more layers.
For the purpose of curing these curable components, a curing agent for each component may be used as appropriate.
3-100 micrometers is preferable and, as for the thickness of an adhesive bond layer, 5-50 micrometers is more preferable.

(Binder resin)
The adhesive layer, to use a binder resin for the purpose of imparting flexibility to the film.

Examples of such a binder resin include (meth) acrylic polymers, rubber polymers, phenoxy resins, urethane resins, polyester resins, polyethylene resins, polystyrene resins, and the like. These may be used alone or in combination of two or more.
Of these, (meth) acrylic polymers, phenoxy resins, and polyester resins are preferred in the present invention.

  Examples of the (meth) acrylic polymer include butyl (meth) acrylate, ethyl (meth) acrylate, methyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, hydroxymethyl (meth) acrylate, (meth) A polymer or copolymer containing a (meth) acrylic acid ester such as hydroxyethyl acrylate as a constituent component is preferable. Further, (meth) acrylic acid or (meth) acrylic acid ester having a hydroxyl group, a carboxyl group, an epoxy group, a nitrile group or the like may be included in the constituent components. There is no restriction | limiting in particular in the preparation method of a (meth) acrylic-type polymer, It can synthesize | combine by normal methods, such as solution polymerization, emulsion polymerization, suspension polymerization, and block polymerization.

  Such a (meth) acrylic polymer preferably has a mass average molecular weight of 50,000 or more, more preferably 10 to 1,000,000. When the mass average molecular weight is 50,000 or more, the flexibility, strength, and tackiness of a sheet or film are appropriate. The mass average molecular weight is a value measured by gel permeation chromatography and converted using a standard polystyrene calibration curve.

  Moreover, -10-30 degreeC is preferable and, as for the glass transition temperature (Tg) of a (meth) acrylic-type polymer, 0-20 degreeC is more preferable.

  Examples of the phenoxy resin include bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenolacetophenone skeleton, novolac skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, terpene Examples thereof include those having one or more skeletons selected from a skeleton and a trimethylcyclohexane skeleton. These may use 1 type (s) or 2 or more types. As a mass average molecular weight of a phenoxy resin, 30,000-100,000 are preferable and it is more preferable that it is 40,000-80,000.

  Specific examples of commercially available phenoxy resins include 1256, 4250 (bisphenol A skeleton-containing phenoxy resin) manufactured by Japan Epoxy Resin Co., Ltd., YX8100 (bisphenol S skeleton-containing phenoxy resin) manufactured by Japan Epoxy Resin Co., Ltd., Japan YX6954 manufactured by Epoxy Resin Co., Ltd. (phenoxy resin containing bisphenolacetophenone skeleton), PKHH manufactured by Union Carbide Co., Ltd. (mass average molecular weight (Mw) 42,600, number average molecular weight (Mn) 11,200), FX280 manufactured by Tohto Kasei Co., Ltd. , FX293, Japan Epoxy Resin Co., Ltd. YL7553BH30, YL6794, YL7213, YL7290, YL7482, etc. Among them, Japan Epoxy Resin Co., Ltd. 1256 (Bisphenol A skeleton-containing phenoxy) Fat), Japan Epoxy Resin Co., Ltd. YX8100 (Bisphenol S skeleton-containing phenoxy resin), Japan Epoxy Resin Co., Ltd. YX6954 (Bisphenol acetophenone skeleton-containing phenoxy resin), Union Carbide PKHH (Mass average molecular weight (Mw)) 42 600, number average molecular weight (Mn) 11,200).

  The polyester resin is obtained by polycondensation of a polyvalent carboxylic acid component and a polyol (glycol) component. Examples of the polyvalent carboxylic acid include known ones such as terephthalic acid, isophthalic acid, orthophthalic acid, succinic acid, adipic acid, sebacic acid, cyclohexanedicarboxylic acid, and trimellitic acid. Examples of the polyol include aliphatic alcohols such as ethylene glycol and propylene glycol, and polyether polyols such as polyethylene glycol and polypropylene glycol. The mass average molecular weight of the polyester resin used in the present invention is preferably 5,000 to 50,000, and more preferably 10,000 to 30,000.

Moreover, it is preferable that it is -20-80 degreeC, and, as for the glass transition temperature (Tg) of the polyester resin used for this invention, it is more preferable that it is 0-60 degreeC.
If the Tg is too high, the flexibility of the resin composition will be inferior. On the other hand, if the Tg is too low, the tackiness of the resin composition will increase and the workability may deteriorate.

  10-90 mass parts is preferable with respect to 100 mass parts of solid content (nonvolatile component), and, as for content in the resin composition of binder resin, 30-70 mass parts is more preferable.

(Curing component)
The curable component refers to a composition that causes a curing reaction by heat, light or the like. Specifically, for example, known polyimide resins used for adhesives, polyamide resins, polyetherimide resins, polyamideimide resins, polyester resins, polyesterimide resins, phenoxy resins, silicone resins, polysulfone resins, polyethersulfone resins, Examples thereof include polyphenylene sulfide resin, polyether ketone resin, chlorinated polypropylene resin, acrylic resin, polyurethane resin, epoxy resin, polyacrylamide resin, melamine resin, and the like and mixtures thereof.
Among these, in the present invention, an epoxy compound or resin having an epoxy group (hereinafter collectively referred to as an epoxy resin) is preferable.

The epoxy resin is not particularly limited as long as it cures and exhibits an adhesive action, but is an epoxy resin having a bifunctional group or more, preferably a molecular weight or a weight average molecular weight of less than 5,000, more preferably less than 3,000. Can be used. Further, an epoxy resin having a molecular weight of preferably 500 or more, more preferably 800 or more can be used.
For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolak type epoxy Resin, diglycidyl etherified product of biphenol, diglycidyl etherified product of naphthalenediol, diglycidyl etherified product of phenol, diglycidyl etherified product of alcohol, and alkyl-substituted products, halides, hydrogenated products, etc. And a novolak-type epoxy resin. Moreover, what is generally known, such as a polyfunctional epoxy resin and a heterocyclic ring-containing epoxy resin, can also be applied. These can be used alone or in combination of two or more. Furthermore, components other than the epoxy resin may be included as impurities within a range that does not impair the characteristics. In the present invention, an epoxy resin having at least two epoxy groups is preferable, and a bisphenol type epoxy resin having a large aromatic ring (p-linked bisphenol or novolac type resin in which the phenolic hydroxyl group is etherified with a glycidyl group) is used. Particularly preferred.
The epoxy equivalent of the epoxy resin is preferably 100 to 1000 g / eq, and more preferably 150 to 500 g / eq.
As for content in the resin composition of an epoxy resin, 10-70 mass parts is preferable with respect to 100 mass parts of all resin compositions by solid content (nonvolatile component), and 20-60 mass parts is more preferable.

(Curing agent)
As a curing agent for the epoxy resin, a compound or resin having a hydroxyl group is preferable, and for example, a phenolic resin can be used. As the phenolic resin, condensates of phenols such as alkylphenols, polyhydric phenols, naphthols, biphenylenes, and aldehydes are used without particular limitation.
In the present invention, a compound having an aromatic ring is preferable, and a compound having the naphthalene skeleton is particularly preferable.

The phenolic hydroxyl group contained in these phenolic resins can easily undergo an addition reaction with the epoxy group of the epoxy resin by heating to form a cured product having high impact resistance.
The hydroxyl equivalent of the phenolic resin is preferably 50 to 300 g / eq, and more preferably 95 to 240 g / eq.

  Further, phenolic resins include phenol novolak resin, o-cresol novolak resin, p-cresol novolak resin, t-butylphenol novolak resin, dicyclopentadiene cresol resin, polyparavinylphenol resin, bisphenol A type novolak resin, phenol biphenylene. Resins or modified products thereof are preferably used.

  As the other curing agent, a thermally activated latent epoxy resin curing agent can also be used. This curing agent is a type of curing agent that does not react with the epoxy resin at room temperature but is activated by heating at a certain temperature or more and reacts with the epoxy resin. As an activation method, a method of generating active species (anions and cations) by a chemical reaction by heating, a dispersion that is stably dispersed in the epoxy resin near room temperature, is compatible with and dissolved in the epoxy resin at a high temperature, and a curing reaction is performed. There are a method for starting, a method for starting a curing reaction by elution at a high temperature with a molecular sieve encapsulated type curing agent, a method using a microcapsule, and the like.

Examples of the thermally active latent epoxy resin curing agent include various onium salts, high melting point active hydrogen compounds such as dibasic acid dihydrazide compounds, dicyandiamide, amine adduct curing agents, and imidazole compounds.
As for content of a hardening | curing agent, 50-200 mass parts is preferable with respect to 100 mass parts of epoxy resins, and 80-120 mass parts is more preferable.

(Curing accelerator)
Moreover, a hardening accelerator etc. can also be used as an adjuvant. There is no restriction | limiting in particular as a hardening accelerator which can be used for this invention, For example, a tertiary amine, imidazoles, a quaternary ammonium salt etc. can be used. Examples of imidazoles preferably used in the present invention include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, and the like. These may be used alone or in combination of two or more. Imidazoles are commercially available, for example, from Shikoku Chemicals Co., Ltd. under the trade names 2E4MZ, 2PZ, 2PZ-CN, and 2PZ-CNS.
As for content of a hardening accelerator, 0.02-5 mass parts is preferable with respect to 100 mass parts of epoxy resins, and 0.1-2 mass parts is more preferable.

(desiccant)
It is preferable to add a desiccant in order to reduce the moisture in the adhesive layer and to reduce moisture permeability. In the present invention, the desiccant is contained in at least one adhesive layer.

The desiccant is not particularly limited, and examples thereof include metal oxides such as silica gel, molecular sieve, magnesium oxide, calcium oxide, barium oxide, and strontium oxide, and magnesium oxide or calcium oxide is preferable. Such a desiccant is preferably a particle having an average particle size of 0.1 to 10 μm, more preferably 0.5 to 5 μm.
The content of the desiccant is preferably 5 to 50 parts by mass, more preferably 10 to 40 parts by mass with respect to 100 parts by mass of the total resin composition in terms of solid content (non-volatile component).
However, in this invention, 10 mass parts or more of desiccants are contained with respect to 100 mass parts of binder resins.

(Other additives)
The adhesive layer may contain a silane coupling agent.
Specific examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 2- (3,4-epoxycyclohexyl). ) Ethyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyltrimethoxysilane 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, N- (2- (vinylbenzylamino) ethyl) 3-aminopropyltrimethoxysilane hydrochloride, 3-methacryloxypropyltri Methoxysilane And the like of the silane coupling agent. Two or more kinds of these silane coupling agents may be mixed. Among these, 3-glycidoxypropyltrimethoxysilane (KBM-403: manufactured by Shin-Etsu Chemical Co., Ltd.) is preferable because of its good compatibility with epoxy resins and excellent stability. 0.05-100 mass parts is preferable with respect to 100 mass parts of binder resins, and, as for content of a silane coupling agent, 0.1-10 mass parts is more preferable.

  In the present invention, as long as the object of the present invention can be achieved, other components such as a storage stabilizer, an antioxidant, a plasticizer, a tack adjuster, a resin stabilizer and the like can be added. Attention should be paid to moisture and impurities in the added components.

From the viewpoint of water permeability, the resin composition of the present invention preferably contains a compound or resin having a skeleton having many aromatic rings, since orientation (crystallinity) is obtained, and particularly, a skeleton having a polycyclic aromatic ring. More preferred are compounds or resins having As polycyclic aromatic rings, condensed polycyclic aromatic rings such as naphthalene rings and phenanthrenes, and structures in which benzene rings are linked, for example, biphenyl skeletons, benzene rings such as bisphenols are linked via a divalent linking group. Structure.
These compounds can be incorporated as a structure of a binder resin, a curing component, a curing agent, a curing accelerator, and other additives. In the present invention, it is particularly preferable to incorporate as a curing component or a curing accelerator.
In the resin composition of the present invention, the content of the compound or resin having a polycyclic aromatic ring skeleton is preferably 5 to 70 parts by mass, more preferably 10 to 50 parts by mass with respect to 100 parts by mass of the resin composition. preferable.

<Peeling sheet>
In the present invention, when the resin composition is formed into an adhesive film, the adhesive layer made of the resin composition preferably has a configuration in which a release sheet is temporarily attached to one side or both sides.
The release sheet is used for the purpose of improving the handleability of the adhesive film and for the purpose of protecting the adhesive layer.
Examples of release sheets include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyphenyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, and polyurethane. Film, ethylene / vinyl acetate copolymer film, ionomer resin film, ethylene / (meth) acrylic acid copolymer film, ethylene / (meth) acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, fluorine Resin film etc. are mentioned. These crosslinked films are also used. Furthermore, these laminated films may be sufficient. In particular, it is preferable to use polyethylene terephthalate from the viewpoints of cost, handleability, and the like.

The surface tension of the release sheet is preferably 40 mN / m or less, and more preferably 35 mN / m or less. Such a release sheet having a low surface tension can be obtained by appropriately selecting the material, and can also be obtained by applying a silicone resin or the like to the surface of the sheet and performing a release treatment.
As an example of the peeling force when peeling the adhesive layer from the release sheet, it is preferably 0.3 N / 20 mm or less, more preferably 0.2 N / 20 mm. Although there is no restriction | limiting in particular in the minimum of peeling force, 0.005 N / 20mm or more is practical. Moreover, when temporarily attaching a peeling film to both surfaces, in order to improve handleability, it is preferable to use a thing with different peeling force.

  The thickness of the release sheet is usually about 5 to 300 μm, preferably about 10 to 200 μm, and particularly preferably about 20 to 100 μm.

<Adhesive film>
The adhesive film in the present invention comprises at least one adhesive layer, and preferably has the release sheet on both sides or one side of the adhesive layer.
The adhesive film may have two or more adhesive layers, or may have a layer other than the adhesive layer.
When it has two or more layers, Preferably two or more layers are adhesive layers. In this case, it is preferable that the outermost layer on the side to which the organic electroluminescence element is bonded and the outermost layer on the side to which the substrate is bonded are adhesive layers.

Further, when the adhesive film has two or more layers, at least one of them is the adhesive layer of the present invention having a desiccant, and the layer on the side to which the organic electroluminescent element is adhered is dried. It is preferable not to contain an agent. Here, when two or more layers are adhesive layers, the outermost layer on the side to which the organic electroluminescence element is bonded is an adhesive layer having no desiccant, and the outermost layer on the side to which the substrate is bonded is dried. It is particularly preferable that the adhesive layer of the present invention contains an agent.
Here, the thickness of the adhesive layer is usually 3 to 100 μm, preferably 5 to 50 μm, but when two or more layers are adhesive layers, the outermost layer on the side to which the organic electroluminescence element is bonded The thickness of is preferably 1 to 15 μm, and more preferably 2 to 10 μm. Further, the thickness of the adhesive layer of the present invention in which the outermost layer on the side to which the substrate is bonded contains a desiccant is more preferably 5 to 50 μm, further preferably 10 to 20 μm. Moreover, it is preferable that the thickness of the adhesive layer of the present invention in which the outermost layer on the side to which the substrate is bonded contains a desiccant is thicker than the adhesive layer on the side to which the organic electroluminescent element is bonded.

  Here, the adhesive layer in which the outermost layer on the side to which the organic electroluminescence element is bonded does not have a desiccant may be any adhesive layer as long as it does not contain a desiccant. The adhesive layer described above is preferred except that it is not included.

The outermost layer on the side to which the organic electroluminescence element is bonded does not contain a desiccant, and the outermost layer on the side to which the substrate is bonded contains a desiccant, whereby damage to the organic EL element can be reduced.
In addition, when a desiccant is contained, an inorganic substance with high hardness may appear as fine protrusions on the surface of the adhesive layer, and this protrusion may damage the conductive electrode layer on the surface of the organic EL element, causing leakage current. This causes a problem of reducing the light emitting function of the organic EL element.

When obtaining the adhesive film of an adhesive bond layer, the resin composition of this invention may contain a solvent.
Examples of such solvents include methyl ethyl ketone, toluene, ethanol, isopropanol solvent and water, organic solvents are preferable, and methyl ethyl ketone and toluene are particularly preferable. Each material contained in the resin composition is added to such a solvent, mixed and dispersed, and the resulting adhesive varnish (dispersion) is applied onto the release surface of the release sheet by a roll knife coater, a gravure coater, a die coater, It can be applied directly or by transfer according to a generally known method such as a reverse coater and dried to obtain an adhesive layer.

<Organic EL element, display device>
The organic EL device of the present invention has a structure sealed with the resin composition of the present invention and an adhesive film.
A preferred embodiment of the organic EL device of the present invention is shown in FIG. In FIG. 2, on a substrate (31), an anode (32), a hole injection layer (33), a hole transport layer (34), a light emitting layer (35), an electron injection layer (36), and a cathode (37). Are provided in this order, and the element is sealed with the sealing material of the present invention to improve airtightness. The adhesive film (adhesive layer) shown in FIG. 2 has an adhesive layer having a two-layer structure, with the desiccant-containing adhesive layer (11) on the outside and the adhesive layer (12 containing no desiccant). ) On the inside, organic EL so as to cover the anode (32), hole injection layer (33), hole transport layer (34), light emitting layer (35), electron injection layer (36) and cathode (37) It is disposed in close contact with the element. In addition, the structure of the organic EL element of the present invention is not limited to the above embodiment, and has the structure of an element that can function as an organic EL element and is sealed with the sealing material of the present invention. Both are included in the organic EL device of the present invention.
The organic EL element of the present invention is an element that is excellent in airtightness and in which deterioration of performance is further suppressed.

  EXAMPLES Hereinafter, although the structure of this invention is demonstrated in detail based on an Example, this invention is not limited to these.

<Preparation of resin composition and sealant>
Example 1
To 100 parts by mass of acrylic polymer A (acrylic polymer having a mass average molecular weight of 800,000, a hydroxyl value of 10 mgKOH / g, and a glass transition temperature (Tg) of 10 ° C.), epoxy resin A (bisphenol A type epoxy having an epoxy equivalent of 170 to 190 g / eq) 50 parts by mass of resin), 50 parts by mass of curing agent A (biphenyl skeleton phenol resin having a hydroxyl group equivalent of 200 to 240 g / eq), and 1 part by mass of curing accelerator A (amine-based accelerator having a reaction start temperature of 110 ° C.) 20 parts by mass of methyl ethyl ketone and MgO as a desiccant were added as a solvent and stirred to obtain a resin composition A. This resin composition A was applied on a base film having a thickness of 25 μm (Separator A31 manufactured by Teijin Limited) with a bar coater and dried to obtain a sealing agent having a thickness of 30 μm.

Example 2
With respect to the resin composition A, the epoxy resin A is an epoxy resin B (biphenyl A type epoxy resin having an epoxy equivalent of 170 to 190 g / eq) and the curing agent A is a curing agent B (hydroxyl equivalent of 140 to 160 g / eq). Resin composition B in the same manner as in resin composition A, except that 50 parts by mass of naphthalene skeleton phenol resin) and curing accelerator A were changed to curing accelerator B (amine-based accelerator having a reaction start temperature of 80 ° C.). Got. This resin composition B was applied onto a base film (separator A31 manufactured by Teijin Ltd.) having a thickness of 25 μm with a bar coater and dried to obtain a sealant having a thickness of 30 μm.

Example 3
To 100 parts by mass of polyester resin B (polyester resin having a mass average molecular weight of 20,000, a hydroxyl value of 5 mg KOH / g, and a glass transition temperature (Tg) of 0 ° C.), an epoxy resin C (epoxy equivalent 140-170 g / eq naphthalene type epoxy resin) ) And 50 parts by mass of curing agent B (a naphthalene skeleton phenol resin having a hydroxyl equivalent weight of 140 to 160 g / eq), and 1 part by mass of curing accelerator D (amine-based accelerator having a reaction start temperature of 70 ° C.), Resin composition C was obtained by adding 10 parts by mass of methyl ethyl ketone and MgO as a desiccant as a solvent and stirring. This resin composition C was applied onto a substrate film having a thickness of 25 μm (Separator A31 manufactured by Teijin Limited) with a bar coater and dried to obtain a sealant having a thickness of 30 μm.

Comparative Example 1
Resin composition A is the same as resin composition A except that 1 part by mass of curing accelerator A of resin composition A is changed to 1 part by mass of curing accelerator C (amine-based accelerator having a reaction start temperature of 145 ° C.). Composition D was obtained. This resin composition D was applied onto a substrate film having a thickness of 25 μm (Separator A31 manufactured by Teijin Limited) with a bar coater and dried to obtain a sealing agent having a thickness of 30 μm.

Comparative Example 2
Resin composition A is the same as resin composition A except that 1 part by mass of curing accelerator A of resin composition A is changed to 1 part by mass of curing accelerator D (amine-based accelerator having a reaction start temperature of 70 ° C.). Composition E was obtained. The resin composition E was applied onto a base film (separator A31 manufactured by Teijin Ltd.) having a thickness of 25 μm with a bar coater and dried to obtain a sealing agent having a thickness of 30 μm.

Comparative Example 3
In the resin composition A, a resin composition F was obtained in the same manner as the resin composition A except that no desiccant was added. This resin composition F was applied onto a substrate film having a thickness of 25 μm (Separator A31 manufactured by Teijin Limited) with a bar coater and dried to obtain a sealing agent having a thickness of 30 μm.

Comparative Example 4
Resin composition G was obtained in the same manner as in resin composition C except that 1 part by mass of curing accelerator D in resin composition C was changed to 1 part by mass of curing accelerator C. This resin composition G was applied onto a base film (separator A31 manufactured by Teijin Ltd.) having a thickness of 25 μm with a bar coater and dried to obtain a sealant having a thickness of 30 μm.

Comparative Example 5
Resin composition H was obtained in the same manner as resin composition C except that the amount of the desiccant of resin composition C was changed to 1 part by mass. By applying and drying this resin composition H, a sealing agent having a thickness of 30 μm was obtained.

Comparative Example 6
To 100 parts by mass of acrylic polymer A (acrylic polymer having a mass average molecular weight of 800,000, a hydroxyl value of 10 mgKOH / g, and a glass transition temperature (Tg) of 10 ° C.), 20 parts by mass of methyl ethyl ketone as a solvent and MgO as a desiccant are added and stirred. Thus, a resin composition I was obtained. The resin composition I was applied onto a base film (separator A31 manufactured by Teijin Ltd.) having a thickness of 25 μm with a bar coater and dried to obtain a sealing agent having a thickness of 30 μm.

  The resins and materials used are as follows.

Binder resin Acrylic polymer A: Mass average molecular weight; 800,000, hydroxyl value: 10 mgKOH / g
Glass transition temperature (Tg); 10 ° C
Polyester resin B: mass average molecular weight; 20,000, hydroxyl value: 5 mg KOH / g
Glass transition temperature (Tg); 0 ° C

Curing component Epoxy resin A: Bisphenol A type epoxy resin
Epoxy equivalent: 170 to 190 g / eq
Epoxy resin B: Biphenyl type epoxy resin
Epoxy equivalent: 170 to 190 g / eq
Epoxy resin C: Naphthalene type epoxy resin
Epoxy equivalent: 140-170 g / eq

Curing agent Curing agent A: Biphenyl skeleton phenolic resin
Hydroxyl equivalent: 200-240 g / eq
Curing agent B: Naphthalene skeleton phenol resin
Hydroxyl equivalent: 140-160 g / eq

Curing accelerator Curing accelerator A: Amine accelerator having a reaction initiation temperature of 110 ° C. Curing accelerator B: Amine accelerator having a reaction initiation temperature of 80 ° C. Curing accelerator C: Amine accelerator having a reaction initiation temperature of 145 ° C. Curing acceleration Agent D: Amine accelerator with a reaction initiation temperature of 70 ° C

Desiccant Magnesium oxide (MgO): Average particle size 0.5 μm

<Production of organic EL element>
After bonding the moisture-proof film sealant to the back substrate under the conditions of 60 ° C. and 0.1 MPa, the surface substrate on which the organic EL element is formed is subjected to the conditions of 80 ° C./0.1 MPa / 30 seconds. The organic EL element (light emitting element) was produced by vacuum bonding.

<Measurement of shear bond strength>
Each shear bond strength measurement of Examples 1-3 and Comparative Examples 1-6 was performed as follows.
The release film on the side to be bonded to the organic EL element side of the adhesive film having release sheets on both sides of the prepared adhesive layer is peeled off and bonded to 5 mm square glass while heating at 60 ° C., and then the sealing substrate is attached. The release sheet of the adhesive layer on the side to be bonded was peeled off and pressure-bonded to 12 mm square glass at 60 ° C./500 gf / 3 s, and the sample thus produced was heated and cured in a heating furnace at 100 ° C. for 3 hours. Thereafter, a sample laminated with glass / adhesive film / glass is prepared, and the shear adhesive strength with the glass is measured.
A sample laminated with glass / adhesive film / glass prepared as described above was treated for 24 hours under the conditions of 85 ° C. and 85% relative humidity, and then a universal bond tester (for example, DAGE series 4000) was used. Then, the shear adhesive strength with glass at a stage temperature of 25 ° C., a head height of 35 μm, and a speed of 50 μm / sec is measured.

<Measurement of DSC exothermic peak and calorific value>
The DSC exothermic peaks and calorific values of Examples 1 to 3 and Comparative Examples 1 to 6 were measured as follows.
Each sealant produced was heat treated at 100 ° C. for 3 hours, then treated at 85 ° C. and a relative humidity of 85% for 24 hours, then 10 mg was measured, EXSTAR DSC7020 manufactured by SII Nanotechnology) Was heated in air to 300 ° C. at a temperature rising rate of 10 ° C./min, and the calorific value was measured. Note that alumina was used as a reference.

<Luminescent characteristics of the element>
After heat treatment at 100 ° C. for 3 hours, after treatment for 24 hours under the conditions of a temperature of 85 ° C. and a relative humidity of 85%, each electroluminescence element was electrically applied to observe the degree of dark spots, and the following evaluation criteria It was evaluated with.
Evaluation criteria ○: Generation of dark spots was not recognized.
(Triangle | delta): Generation | occurrence | production of the dark spot was recognized slightly.
X: The occurrence of dark spots was clearly observed.

<Measurement of peeling from substrate>
After heat treatment at 100 ° C. for 3 hours, after treatment for 24 hours under conditions of a temperature of 85 ° C. and a relative humidity of 85%, the presence or absence of peeling is judged by observing from the substrate side and the sealing glass side, and the following evaluation Evaluated by criteria.
Evaluation criteria ○: No peeling occurred.
Δ: Slight peeling occurred.
X: Clear peeling occurred.

  The obtained results are summarized in Tables 1 and 2 below.

  As shown in Tables 1 and 2 above, each sealing agent shown in Examples 1 to 3 showed very good results.

1 Adhesive film (adhesive layer)
DESCRIPTION OF SYMBOLS 11 Adhesive layer containing desiccant 12 Adhesive layer not containing desiccant 30 Sealed organic EL element 31 Substrate 32 Anode 33 Hole injection layer 34 Hole transport layer 35 Light emitting layer 36 Electron injection layer 37 Cathode

Claims (12)

A resin composition for sealing an organic electroluminescence device comprising at least a curable component , a binder resin and a desiccant,
Containing 10 parts by mass or more of the desiccant with respect to 100 parts by mass of the binder resin;
After curing treatment at 100 ° C. 3 h, 85 ° C., 85% relative humidity, when the moisture absorption treatment under conditions of 24 hours, 1) I der shear bond strength than 1MPa the glass, 2) exothermic peak by DSC A resin composition for sealing an organic electroluminescence element , which can be confirmed and has a characteristic that the calorific value is 50 J / g or more . The resin composition for sealing an organic electroluminescent element according to claim 1, wherein the resin composition is a thermosetting type. The exothermic peak temperature in the DSC can be confirmed in a range of 100 ° C to 180 ° C, The resin composition for sealing an organic electroluminescence element according to claim 1 or 2 . The resin composition for sealing an organic electroluminescent element according to any one of claims 1 to 3, wherein the curable component is an epoxy compound or resin having an epoxy group. The curable component, an epoxy compound or resin having an epoxy group, an organic electroluminescence element encapsulation resin according to any one of claims 1 to 4, further characterized in that it comprises a phenolic curing agent Composition. The resin composition for sealing an organic electroluminescent element according to claim 5, wherein the phenolic curing agent is contained in an amount of 50 to 200 parts by mass with respect to 100 parts by mass of the epoxy compound or resin having the epoxy group. . The resin composition for sealing an organic electroluminescent element according to any one of claims 1 to 6 , wherein the resin composition contains a compound or a resin having a skeleton of a polycyclic aromatic ring. . 8. The resin composition for sealing an organic electroluminescent element according to claim 7, wherein the compound or resin having a skeleton of a polycyclic aromatic ring is a compound or resin having a hydroxyl group and a naphthalene skeleton. The organic electroluminescence according to any one of claims 1 to 8, further comprising at least one curing accelerator selected from tertiary amines, imidazoles, and quaternary ammonium salts. Resin composition for device sealing. 10. The content of the binder resin in the resin composition is 10 to 90 parts by mass with respect to 100 parts by mass of the solid content (nonvolatile component), according to claim 1. A resin composition for sealing an organic electroluminescence element. An organic electroluminescent device comprising sealed with a resin composition according to any one of claims 1-10. A display device comprising the organic electroluminescence element according to claim 11 .

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