JP6649243B2 - Desiccant composition, sealing structure, and organic EL device - Google Patents

Description

  The present invention relates to a desiccant composition, a sealing structure, and an organic EL device.

  An organic EL element generally has an organic layer containing an organic light emitting material, and it is desired to prevent generation and growth of non-light emitting portions of the organic layer called dark spots. It is known that the main cause of dark spots is largely affected by moisture and oxygen. In particular, it is known that even a very small amount of moisture has a large effect on the generation of dark spots.

  Therefore, various methods for preventing the entry of moisture and oxygen into the organic EL element have been studied. For example, there has been proposed a hollow sealing structure in which an organic layer and electrodes are sealed in an airtight container in a dried inert gas atmosphere, and a drying agent is further sealed in the airtight container. For example, Patent Document 1 discloses an organic EL device including a desiccant layer formed by mixing and dispersing oxide particles such as diphosphorus pentoxide as a desiccant in a resin on the inner surface of a sealing cap. . Here, a silicone resin, an epoxy resin, or the like is used as the resin.

JP 2001-035659 A

  However, in a conventional organic EL device having a desiccant layer containing a silicone resin or the like, the organic layer in the organic EL device may be dissolved during long-term storage. It is considered that this is because the silicone resin or the like exudes from the desiccant layer and this dissolves the organic layer.

  It is expected that the use of a curable resin as a resin for dispersing the oxide particles of the desiccant and curing of the resin will suppress the exudation of the resin component from the desiccant layer. However, a desiccant composition for forming a desiccant layer containing a curable resin sometimes thickens during storage or use due to an unintended progress of a curing reaction. When a desiccant composition containing a curable resin is used, a desiccant layer is often formed by applying and curing the desiccant composition, but for stable application, the viscosity of the desiccant composition is stable for a long time. Is desirable in the manufacturing process.

  Therefore, one aspect of the present invention has as its main object to provide a desiccant composition that can form a desiccant layer in which the exudation of components is suppressed and that has excellent stability over a long period of viscosity. .

  One aspect of the present invention is a desiccant comprising a (meth) acrylic group, a high molecular weight (meth) acrylic compound which is liquid at 25 ° C., and oxide particles containing an oxide of an alkaline earth metal. A composition is provided.

  This desiccant composition can form a desiccant layer in which exudation of components is suppressed, and can have excellent viscosity stability. The (meth) acrylic compound tends to polymerize during storage when oxide particles coexist, but by using a high molecular weight (meth) acrylic compound, the viscosity increase due to such polymerization is suppressed. By using a liquid at room temperature (25 ° C.) as the high molecular weight (meth) acrylic compound, the desiccant composition can have fluidity suitable for application.

  The viscosity at 25 ° C. of the desiccant composition after being left for 24 hours or 48 hours in an environment of 25 ° C. is within + 10% of the viscosity at 25 ° C. of the desiccant composition before being left. Is also good. By adjusting the content, molecular weight, and the like of the high molecular weight (meth) acrylic compound, the desiccant composition can be easily reduced in such a viscosity change.

  The high molecular weight (meth) acrylic compound may be a liquid modified polybutadiene having a (meth) acryloyloxy group, a liquid modified silicone having a (meth) acryloyloxy group, or a combination thereof.

  In another aspect, the present invention is provided between a pair of substrates disposed opposite to each other, a sealing sealant for sealing an outer peripheral portion of the pair of substrates, and a pair of substrates inside the sealing sealant. And a desiccant layer which is a cured product of the desiccant composition.

  In still another aspect, the present invention provides an element substrate, a sealing substrate opposed to the element substrate, a sealing agent for sealing the outer periphery of the element substrate and the sealing substrate, and a sealing seal. A layered body having an organic layer and a pair of electrodes sandwiching the organic layer, provided on the element substrate inside the agent, and the drying agent composition provided on the sealing substrate inside the sealing agent. An organic EL device comprising: a desiccant layer that is a cured product.

  ADVANTAGE OF THE INVENTION According to this invention, the desiccant layer in which the exudation of the component was suppressed can be formed, and also the desiccant composition excellent in the stability over a long time of the viscosity can be provided.

FIG. 2 is a schematic cross-sectional view showing one embodiment of an organic EL element. It is a graph which shows the relationship between the viscosity of a desiccant composition, and a leaving time.

  Hereinafter, some embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In the present specification, “(meth) acryl” means acryl, methacryl, or both. This applies to other similar expressions such as a (meth) acryloyloxy group.

<Drying agent composition>
The desiccant composition according to one embodiment is a curable composition containing a high molecular weight (meth) acryl compound having a (meth) acryl group and oxide particles containing an oxide of an alkaline earth metal.

  The high molecular weight (meth) acrylic compound is a high molecular weight radical polymerizable compound having one or more (meth) acrylic groups (typically, (meth) acryloyloxy group) in the molecule. From the viewpoint of curability and suppression of exudation of components, the high molecular weight (meth) acrylic compound may have two or more (meth) acrylic groups and may have two (meth) acrylic groups. You may.

  The high molecular weight (meth) acrylic compound is liquid at 25 ° C. In other words, the high molecular weight (meth) acrylic compound does not solidify at 25 ° C., but is liquid and has a certain high molecular weight. By introducing a liquid and high molecular weight (meth) acrylic compound in this manner, a desiccant composition having excellent viscosity stability over a long period of time can be obtained. In addition, a high molecular weight (meth) acrylic compound is advantageous for suppressing damage to the organic EL element due to volatiles from the drying agent layer. More specifically, the molecular weight of the high molecular weight (meth) acrylic compound may be, for example, 900 or more, 3000 or more, 4000 or more, 5000 or more, 6000 or more, 7000 or 8000 or more, 30,000 or less, 20,000 or less, Or it may be 15,000 or less. These molecular weights may be number average molecular weights.

  The functional group equivalent (molecular weight per (meth) acrylic group) of the high molecular weight (meth) acrylic compound may be 450 to 15,000. Thereby, it is possible to make a particularly significant contribution to improving the stability of viscosity while being liquid. From the same viewpoint, the functional group equivalent of the high molecular weight (meth) acrylic compound may be 1000 or more, 1400 or more, 2000 or more, 2500 or more, 3000 or more, 3500 or more, or 4000 or more, or 10,000 or 7500 or less. It may be as follows.

  The high molecular weight (meth) acrylic compound may be a liquid-modified polybutadiene having a (meth) acryloyloxy group, a liquid-modified silicone having a (meth) acryloyloxy group, or a combination of these two.

The liquid-modified polybutadiene is represented, for example, by the following formula (I). In the formula (I), R ¹ and R ² each independently represent a hydrogen atom or a methyl group, and l, m and n each independently represent an integer of 1 or more. The order in which the repeating units are linked is arbitrary.

The liquid-modified silicone is represented, for example, by the following formula (II). In Formula (II), R ³ and R ⁴ each independently represent a divalent organic group, R ⁵ and R ⁶ each independently represent a hydrogen atom or a methyl group, and x represents an integer of 1 or more. R ³ and R ⁴ may be an alkylene group.

  The desiccant composition may further contain another polymerizable compound copolymerizable with the high molecular weight (meth) acrylic compound. Other polymerizable compounds may have one or more (meth) acryloyl groups and may include (meth) acrylic compounds having a molecular weight of less than 900. From the viewpoint of the effect of improving the stability of the viscosity, the content of the high-molecular-weight (meth) acrylic compound is 80 to 100% by mass, based on the total amount of the high-molecular-weight (meth) acrylic compound and other polymerizable compounds. It may be 90 to 100% by mass.

  Examples of the (meth) acryl compound having one (meth) acryloyl group include (meth) acrylic acid; (meth) acrylamide; methyl (meth) acrylate, ethyl (meth) acrylate, and n-butyl (meth). A) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isodecyl (meth) acrylate, dodecyl (meth) acrylate (n-lauryl (meth) A)) an alkyl (meth) acrylate having 1 to 24 carbon atoms in an alkyl group such as acrylate) and stearyl (meth) acrylate; (meth) having an aromatic hydrocarbon group such as benzyl (meth) acrylate and phenoxyethyl (meth) acrylate Acrylate, cyclohe (Meth) acrylates having an alicyclic group such as sil (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate; methoxypolyethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate Alkylene glycol chain-containing (meth) acrylates are exemplified.

  Examples of the (meth) acrylic compound having two or more (meth) acryloyl groups include, for example, alkylene diol di (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, and polyethylene glycol di (meth) acrylate. A) acrylates, and polypropylene glycol di (meth) acrylate.

  These (meth) acrylic compounds can be used alone or in combination of two or more.

  The total amount of the high molecular weight (meth) acrylic compound and other polymerizable compounds in the desiccant composition may be 30 to 90% by mass based on the total mass of the desiccant composition. When the content of the polymerizable compound is in this range, there is a tendency that more excellent coatability and water replenishment performance are easily ensured. From the same viewpoint, the total amount of the high molecular weight (meth) acrylic compound and the other polymerizable compound may be 30% by mass or more or 50% by mass or more, and 90% by mass or less or 70% by mass or less. Is also good.

  The oxide particles in the desiccant composition include an oxide of an alkaline earth metal that can provide the oxide particles with water replenishing performance. The oxide particles usually contain at least 80% by mass or 90% by mass or more of an alkaline earth metal oxide based on the mass of the oxide particles. The oxide particles may include one or two or more alkaline earth metal oxides having different components.

  Examples of the alkaline earth metal oxide include magnesium oxide (MgO), calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO). The alkaline earth metal oxide may be magnesium oxide and / or calcium oxide.

  The average particle size of the oxide particles is not particularly limited, but may be, for example, 0.01 to 30 μm. When the average particle size of the oxide particles is in this range, higher water replenishment performance tends to be obtained. From the same viewpoint, the average particle diameter of the oxide particles may be 0.1 μm or more, 0.5 μm or more, or 1 μm or more, and may be 20 μm or less, 10 μm or less, or 5 μm or less.

  In the present specification, the average particle size of the oxide particles means a median value of a volume distribution measured by a dynamic light scattering type particle size distribution meter. The average particle size is a value measured using a dispersion prepared by dispersing oxide particles in a predetermined dispersion medium.

The specific surface area of the oxide particles may be from 5 to 60 m ² / g. When the specific surface area is 5 to 60 m ² / g, the desiccant can have more excellent water capturing performance. From a similar viewpoint, the specific surface area of the oxide particles may be 10 m ² / g or more, or 15 m ² / g or more, and 50 m ² / g or less, 40 m ² / g or less, or 35 m ² / g or less. You may. Here, the specific surface area means a value measured by the BET method.

The oxide particles containing calcium oxide are, for example, a step of obtaining a slaked lime (Ca (OH) ₂ ) by hydroxylating quick lime (CaO), a step of firing the slaked lime to obtain quick lime, and a step of pulverizing quick lime. And can be obtained by a method provided in this order.

  The oxide particles may be surface-modified with an organic acid or an acid anhydride. By the surface modification of the oxide particles, the basicity of the surface of the oxide particles is reduced, and as a result, an unintended polymerization reaction of a polymerizable compound including a high molecular weight (meth) acrylic compound can be further suppressed. You.

  The oxide particles can be surface-modified with an organic acid and / or anhydride by a method including mixing the oxide particles with an organic acid and / or anhydride. The surface modification of the oxide particles can be confirmed by, for example, generating heat when the oxide particles are mixed with an organic acid and / or anhydride.

  The content of the oxide particles in the desiccant composition may be 5 to 70% by mass based on the total mass of the desiccant composition. When the content of the oxide particles is in this range, higher water replenishment performance tends to be obtained. From the same viewpoint, the content of the oxide particles may be 10% by mass or more or 30% by mass or more, and may be 60% by mass or less or 50% by mass or less.

  The desiccant composition may further contain a photopolymerization initiator for efficient photocuring. Examples of the photopolymerization initiator include 1-hydroxy-cyclohexyl-phenyl-ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone, 2,2-dimethoxy-1, 2-diphenylethan-1-one, 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2 -Hydroxy-2-methyl-1-propan-1-one.

  When the desiccant composition contains a photopolymerization initiator, the content is based on the mass of the polymerizable compound in the desiccant composition (the total amount of the high-molecular-weight (meth) acrylic compound and other polymerizable compounds). For example, it may be 0.01 to 10% by mass.

By curing (particularly photocuring) the composition layer, a desiccant layer which is a cured product of the desiccant composition can be formed. The type of light for curing is not particularly limited as long as the curing reaction proceeds. For example, UV (ultraviolet) light may be used. Examples of the light source include a mercury lamp such as a low-pressure mercury lamp. The irradiation amount required for curing can be, for example, 1 to 10 J / cm ² . The time required for curing can be, for example, 0.5 to 5 minutes.

  The desiccant composition can be in the form of a paste at 25 ° C. When the desiccant composition is in the form of a paste, the composition layer can be more easily formed by applying the desiccant composition in a minute airtight space of the organic EL element. The viscosity at 25 ° C. of the desiccant composition may be 5 to 500 Pa · s. When the viscosity at 25 ° C. of the desiccant composition is within this range, the composition layer can be more easily formed by coating. From the same viewpoint, the viscosity of the desiccant composition may be 10 Pa · s or more or 50 Pa · s or more, and may be 400 Pa · s or less or 300 Pa · s or less. The viscosity here is a value measured by a rotational viscometer such as a B-type viscometer or a rheometer.

  The desiccant composition can have a stable viscosity when left at room temperature (25 ° C.). Specifically, the viscosity at 25 ° C. of the desiccant composition after being left for 24 hours or 48 hours in an environment of 25 ° C. is within + 10% of the viscosity of the desiccant composition before being left. Can be. The desiccant composition having such high viscosity stability can form a desiccant layer stably. By the combination of the oxide particles and the high molecular weight (meth) acryl compound, a desiccant composition having such high viscosity stability can be easily obtained.

<Sealing structure>
The sealing structure according to one embodiment is provided between a pair of substrates disposed opposite to each other, a sealing sealant that seals an outer peripheral portion of the pair of substrates, and a pair of substrates inside the sealing sealant. A desiccant layer. The desiccant layer can include the desiccant according to the above-described embodiment. The desiccant layer may fill the sealed space (the space between the pair of substrates inside the sealing sealant).

  The sealing structure of the present embodiment can be particularly suitably used when enclosing a device that is easily affected by moisture. Examples of such a device include organic electronic devices such as an organic EL element, an organic semiconductor, and an organic solar cell.

<Organic EL device>
FIG. 1 is a schematic sectional view showing an embodiment of the organic EL device. The organic EL element 1 shown in FIG. 1 sandwiches an element substrate 2, a sealing substrate 3 arranged to face the element substrate 2, and an organic layer 4 and an organic layer 4 provided on the element substrate 2. A laminate having an anode 5 and a cathode 6, a sealing sealant 8 for sealing the outer peripheral portions of the element substrate 2 and the sealing substrate 3, and provided on the sealing substrate 3 inside the sealing sealant 8. This is an organic EL element having a so-called hollow sealing structure composed of the desiccant layer 7. The desiccant layer 7 can be a cured product of the desiccant composition of the above embodiment. Since the desiccant layer 7 is a cured product of the composition of the above-described embodiment, the exudation of components contained in the desiccant layer can be suppressed. However, the organic EL element is not limited to the hollow sealing structure as shown in FIG. 1, and includes, for example, a desiccant layer filled in an airtight space surrounded by an element substrate, a sealing substrate, and a sealing seal layer. An organic EL element having a filling structure may be used.

  In the organic EL element 1, a normal configuration can be applied to elements other than the desiccant layer 7, and an example thereof will be briefly described below.

  The element substrate 2 is formed of a rectangular glass substrate having an insulating property and a light transmitting property. An anode 5 (electrode) is formed on the element substrate 2 by using ITO (Indium Tin Oxide) which is a transparent conductive material. I have. The anode 5 is formed by patterning an ITO film formed on the element substrate 2 by a PVD (Physical Vapor Deposition) method such as a vacuum evaporation method or a sputtering method into a predetermined pattern shape by etching using a photoresist method. Is done. A part of the anode 5 as an electrode is drawn out to the end of the element substrate 2 and connected to a drive circuit (not shown).

An organic layer 4 which is a thin film containing an organic light emitting material is laminated on the upper surface of the anode 5 by, for example, a PVD method such as a vacuum evaporation method and a resistance heating method. The organic layer 4 may be formed from a single layer, or may be formed from a plurality of layers having different functions. The organic layer 4 in the present embodiment has a four-layer structure in which a hole injection layer 4a, a hole transport layer 4b, a light emitting layer 4c, and an electron transport layer 4d are stacked in this order from the anode 5 side. The hole injection layer 4a is formed of, for example, copper phthalocyanine (CuPc) having a thickness of several tens of nm. The hole transport layer 4b is formed of, for example, bis [N- (1-naphthyl) -N-phenyl] benzidine (α-NPD) having a thickness of several tens nm. The light emitting layer 4c is formed of, for example, tris (8-quinolinolato) aluminum (Alq ₃ ) having a thickness of several tens of nm. The electron transport layer 4d is formed of, for example, lithium fluoride (LiF) having a thickness of several nm. A light emitting portion is formed by a laminate in which the anode 5, the organic layer 4, and the cathode 6 described later are laminated in this order.

  On the upper surface of the organic layer 4 (electron transport layer 4d), a cathode 6 (electrode) as a metal thin film is laminated by a PVD method such as a vacuum evaporation method. As the material of the metal thin film, for example, a simple metal having a small work function such as Al, Li, Mg, and In, and an alloy having a small work function such as Al-Li and Mg-Ag are exemplified. The cathode 6 is formed to have a thickness of, for example, several tens to several hundreds of nm (preferably, 50 to 200 nm). A part of the cathode 6 is drawn out to the end of the element substrate 2 and connected to a drive circuit.

  The sealing substrate 3 is disposed so as to face the element substrate 2 with the organic layer 4 interposed therebetween, and the outer peripheral portions of the element substrate 2 and the sealing substrate 3 are sealed with a sealing sealant 8. As the sealing sealant, for example, an ultraviolet curable resin can be used. Further, the desiccant layer 7 is provided on a part or all of the sealing substrate 3 inside the sealing sealant 8. The desiccant layer 7 is formed by applying the desiccant of the above embodiment. The desiccant layer 7 is formed with a thickness of 1 to 300 μm.

  In the organic EL element, for example, a desiccant composition is applied on the sealing substrate 3 to form a desiccant composition layer, and a sealing agent 8 is applied so as to surround the desiccant composition layer. Curing the desiccant composition layer to form a desiccant layer 7; bonding the element substrate 2 on which the organic layer 4 and the like are laminated to the sealing substrate 3; 8 can be produced by a method including curing. The desiccant composition and the sealing sealant can be applied using, for example, a dispenser, and the application is preferably performed in a glove box replaced with nitrogen having a dew point of −76 ° C. or less. The applied desiccant composition can include a solvent, but is typically substantially solvent-free. The sealing sealant can usually be cured by UV irradiation and / or heating.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

1. Preparation of desiccant composition (Example 1)
100 parts by mass of calcium oxide particles (average particle size: 2 μm, specific surface area: 18 m ² / g), liquid modified polybutadiene represented by the formula (I) (polybutadiene diacrylate, product name: BAC-45, molecular weight: about 10,000, Osaka Organic) 100 parts by mass (manufactured by Chemical Industry Co., Ltd.) and 1 part by mass of 2,2-dimethoxy-1,2-diphenylethan-1-one (radical polymerization initiator, product name: IRGACURE651, manufactured by BASF) at 1000 rpm. For 5 minutes to obtain a desiccant composition in the form of a white paste.

(Example 2)
A white paste-like desiccant composition was obtained in the same manner as in Example 1, except that the amount of calcium oxide particles was changed to 120 parts by mass and the amount of the liquid modified polybutadiene was changed to 80 parts by mass.

(Example 3)
120 parts by mass of calcium oxide particles (average particle size 2 μm, specific surface area 18 m ² / g), liquid modified silicone represented by the formula (II (product name: X-22-2445, viscosity: 55 mPa · s (25 ° C.), 80 parts by mass of functional group equivalent: 1600 g / mol, manufactured by Shin-Etsu Chemical Co., Ltd., and 2,2-dimethoxy-1,2-diphenylethan-1-one (radical polymerization initiator, product name: IRGACURE651, manufactured by BASF) 1) One part by mass was centrifuged at 1,000 rpm for 5 minutes to obtain a desiccant composition in the form of a white paste.

(Comparative Example 1)
100 parts by mass of calcium oxide particles (average particle size 2 μm, specific surface area 18 m ² / g), 100 parts by mass of polypropylene glycol diacrylate (product name: APG-700, manufactured by Shin-Nakamura Chemical Co., Ltd., molecular weight: 808), 2, 1 part by mass of 2-dimethoxy-1,2-diphenylethan-1-one (radical polymerization initiator, product name: IRGACURE651, manufactured by BASF) is centrifuged at 1,000 rpm for 5 minutes to prepare a desiccant composition. Obtained. The resulting desiccant composition was immediately cured in a room temperature environment.

(Comparative Example 2)
100 parts by mass of calcium oxide particles (average particle size: 2 μm, specific surface area: 18 m ² / g), 100 parts by mass of polypropylene glycol diacrylate (product name: APG-700, manufactured by Shin-Nakamura Chemical Co., Ltd., molecular weight: 808), benzoic acid 5 parts by mass and 1 part by mass of 2,2-dimethoxy-1,2-diphenylethan-1-one (radical polymerization initiator, product name: IRGACURE651, manufactured by BASF) are centrifuged and stirred at 1,000 rpm for 5 minutes. Thus, a white paste-like desiccant composition was obtained.

2. Evaluation [Viscosity stability of desiccant composition]
Each desiccant composition was allowed to stand in an environment at normal temperature (25 ° C.), and the change with time in viscosity at 25 ° C. in that state was measured. Table 1 shows the measurement results of the viscosity as relative values (%) to the viscosity before standing (0 hour). Since the desiccant composition of Comparative Example 1 was cured in a short time after preparation, the viscosity could not be measured. The viscosity of the desiccant compositions of Examples 1 to 3 after standing for 24 hours was in the range of + 10% with respect to the desiccant compositions before (0 hour). FIG. 2 is a graph showing the relationship between the relative value of the viscosity and time, including a longer standing time, for Comparative Example 2, Example 1, and Example 2. In FIG. 2, the viscosity is shown as a percentage based on the initial viscosity. As shown in FIG. 2, the desiccant compositions of Examples 1 and 2 maintained a state in which the change in viscosity was small for a long time exceeding 48 hours.

[Production of organic EL element]
A transparent conductive material, ITO, was deposited to a thickness of 140 nm over the element substrate by a sputtering method. The ITO film was patterned into a predetermined pattern shape by etching using a photoresist method to form an anode.

A hole injection layer is formed by depositing copper phthalocyanine (CuPc) to a thickness of 70 nm by a resistance heating method on the upper surface of the formed anode, and Bis [N- (1-naphthyl) is formed on the upper surface of the hole injection layer. [N-phenyl] benzidine (α-NPD) with a film thickness of 30 nm to form a hole transport layer, and a 50 nm film of tris (8-quinolinolato) aluminum (Alq ₃ ) on the upper surface of the hole transport layer. A light emitting layer was formed by forming a film having a large thickness. Further, an electron transporting layer was formed by depositing lithium fluoride (LiF) to a thickness of 7 nm on the upper surface of the light emitting layer, and aluminum was physically deposited to a thickness of 150 nm as a cathode on the surface of the electron transporting layer. As described above, a laminate in which the anode, the organic layer (the hole injection layer / the hole transport layer / the light emitting layer / the electron transport layer) and the cathode were laminated in this order was formed on the element substrate.

Next, the desiccant composition of Example 1 was applied to the central portion of the sealing substrate by a dispenser in a glove box replaced with nitrogen having a dew point of −76 ° C. or lower. The desiccant composition of Example 1 was cured by irradiation with a total of 6 J / cm ² of UV (ultraviolet rays) for 3 minutes after application to form a desiccant layer.

  Thereafter, the element substrate and the sealing substrate were bonded together such that the laminate, the desiccant layer, and the sealing sealant faced inside. In this state, the outer peripheral portions of the element substrate and the sealing substrate are sealed by ultraviolet irradiation and heating at 80 ° C., and a hollow sealing structure in which a desiccant layer is provided in an airtight space surrounded by a sealing sealant. An organic EL device was obtained.

[Leakage distance with respect to elapsed time]
The obtained organic EL device was allowed to stand under a condition of 25 ° C., and the time-dependent change in the exudation distance of the desiccant layer component was measured. The exudation distance indicates the distance from the desiccant layer to the end of the portion where the components of the desiccant layer have exuded, and a larger value means that the exudation of the components of the desiccant layer is progressing. . No exudation of the desiccant component was observed until after 500 hours.

  DESCRIPTION OF SYMBOLS 1 ... Organic EL element, 2 ... Element substrate, 3 ... Sealing substrate, 4 ... Organic layer, 4a ... Hole injection layer, 4b ... Hole transport layer, 4c ... Light emitting layer, 4d ... Electron transport layer, 5 ... Anode, 6 ... a cathode, 7 ... a desiccant layer, 8 ... a sealing sealant.

Claims (3)

A high molecular weight (meth) acrylic compound having a (meth) acrylic group and being liquid at 25 ° C.,
Oxide particles containing an oxide of an alkaline earth metal,
A desiccant composition containing
The high molecular weight (meth) acrylic compound has a molecular weight of 900 to 30,000,
The high-molecular-weight (meth) acrylic compound is a liquid-modified polybutadiene having a (meth) acryloyloxy group, a liquid-modified silicone having a (meth) acryloyloxy group, or a combination thereof;
The liquid-modified silicone is represented by the following formula (II):

In formula (II), R ³ and R ⁴ each independently represent a divalent organic group, R ⁵ and R ⁶ each independently represent a hydrogen atom or a methyl group, x represents an integer of 1 or more;
The content of the oxide particles is more than 30% by mass and 60% by mass or less based on the total mass of the desiccant composition;
The desiccant composition may further contain another polymerizable compound copolymerizable with the high molecular weight (meth) acrylic compound, wherein the other polymerizable compound is one or two or more ( A (meth) acrylic compound having a (meth) acryloyl group and a molecular weight of less than 900, wherein the total amount of the high-molecular-weight (meth) acrylic compound and the other polymerizable compound is the total mass of the desiccant composition der 40 wt% to 70 wt% with respect to Ri
The viscosity at 25 ° C. of the desiccant composition is 5 to 500 Pa · s ,
Desiccant composition. A pair of substrates arranged opposite to each other,
A sealing sealant for sealing the outer peripheral portions of the pair of substrates,
A desiccant layer, which is a cured product of the desiccant composition according to claim 1, provided between the pair of substrates inside the sealing sealant,
A sealing structure comprising: An element substrate,
A sealing substrate opposed to the element substrate,
A sealing sealant for sealing an outer peripheral portion of the element substrate and the sealing substrate,
A laminate having an organic layer and a pair of electrodes sandwiching the organic layer, provided on the element substrate inside the sealing sealant,
A desiccant layer, which is a cured product of the desiccant composition according to claim 1, provided on the sealing substrate inside the sealing sealant,
An organic EL device comprising:

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