Encapsulant composition for organic light-emitting diode, and encapsulant prepared using same

Abstract

The present invention relates to an encapsulant composition for an organic light-emitting diode, comprising: 1) a polyorganosiloxane having an average of 0.5 or more alkenyl groups bound to a silicon atom in one molecule; 2) a polyorganohydrogensiloxane having an average of two or more hydrogen atoms bound to a silicon atom in one molecule; 3) a platinum-based catalyst; and 4) a reaction inhibitor including a compound having at least two unsaturated ethylene groups, wherein the amount of the reaction inhibitor is 0.005-1.2 wt% on the basis of the total weight of the polyorganosiloxane, and the amount of ions, other than platinum group element ions, is 50 ppm or less on the basis of the total weight of the encapsulant composition.

Description

Encapsulating composition for organic light-emitting devices and encapsulating material manufactured using the same

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0028615, filed February 28, 2024, and Korean Patent Application No. 2025-0025946, filed February 27, 2025, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a sealing material composition for an organic light-emitting device and a sealing material manufactured using the same.

[0003] In general, organic electronic devices are devices characterized by phenomena such as light emission or electric flow occurring when a charge is injected into an organic layer provided between an anode and a cathode, and devices with various functions can be manufactured depending on the selected organic material.

[0004] As a representative example, organic light emitting diodes (OLEDs) are thin, light, and have excellent color quality, and are attracting attention in the fields of next-generation flat panel displays, flexible displays, and lighting. They can be manufactured on flexible substrates such as existing glass substrates, inorganic substrates including silicon, metal substrates, plastic substrates, or metal foils. Specifically, the organic light emitting diode has a mechanism in which, when electricity is applied, electrons injected from the cathode and holes injected from the anode meet in the emissive layer (EML) to form excitons, and depending on the material of the emissive layer, emit red (R), green (G), or blue (B) light.

[0005] These organic light-emitting devices are highly susceptible to moisture and oxygen, and thus have the disadvantage of significantly reducing their luminous efficiency and lifespan when exposed to the air or when moisture enters the panel from the outside.

[0006] Therefore, it is important to prevent oxidation of light-emitting materials and electrode materials by blocking moisture and oxygen from entering from outside the device through appropriate encapsulation technology, and further protect the device from mechanical and physical shocks applied from outside the device.

[0007] That is, there is a need for the development of a technology that can improve the lifespan of organic light-emitting devices by protecting them from mechanical and physical shocks without affecting their luminous efficiency.

[0008] The present invention aims to provide a composition capable of producing a sealing material that can improve the lifespan of an organic light-emitting device and effectively block oxygen and moisture from entering from the outside, and a sealing material using the same.

[0009] One embodiment of the present invention is:

[0010] 1) Polyorganosiloxane having an average of 0.5 or more alkenyl groups bonded to silicon atoms in one molecule;

[0011] 2) Polyorganohydrogensiloxane having an average of two or more hydrogen atoms bonded to silicon atoms in one molecule;

[0012] 3) hydrosilylation catalyst; and

[0013] 4) Containing a reaction inhibitor comprising a compound having at least two unsaturated ethylene groups,

[0014] Based on the total weight of the polyorganosiloxane, the content of the reaction inhibitor is 0.005 wt% to 1.2 wt%,

[0015] A sealing composition is provided, wherein the content of ions other than platinum group element ions is 50 ppm or less based on the total weight of the sealing composition.

[0016] In addition, another embodiment of the present invention provides a sealant for an organic light-emitting device, which is a cured product of the sealant composition.

[0017] In addition, another embodiment of the present invention provides an organic light-emitting device including the encapsulating material.

[0018] In addition, another embodiment of the present invention comprises the steps of applying the encapsulant composition onto an organic light-emitting device; and

[0019] A step of curing the applied sealing composition at 23°C to 100°C

[0020] A method for encapsulating an organic light-emitting device including a .

[0021] A sealing composition according to one embodiment of the present invention has the characteristics of being able to produce a sealing material that can improve the lifespan of an organic light-emitting device and effectively block oxygen and moisture, etc., from entering from the outside.

[0022] In addition, since the encapsulating composition of the present invention has a minimized content of ionic impurities, when an organic light-emitting device is encapsulated using the encapsulating composition, the influence of ions can be blocked, thereby improving the luminous efficiency and lifespan of the organic light-emitting device.

[0023] In addition, the sealing composition according to one embodiment of the present invention can maintain good curing reactivity and storage stability by including a reaction inhibitor including a compound having at least two unsaturated ethylene groups, particularly one or more reaction inhibitors selected from among diallyl phthalate, diallyl maleate, diallyl oxalate, and tri-allyl isocyanurate, in a specific content range, and thus can exhibit a characteristic of maintaining the effective pixel area of ​​an organic light-emitting device without decreasing even after a long-term test of storing at 85°C for 500 hours.

[0024] Figure 1 is a diagram visualizing cases where the effective pixel area ratios of organic light-emitting devices are 100%, 70%, and 30%, respectively.

[0025] Figure 2 is a diagram visualizing cases where the luminous efficiency of the organic light-emitting device is 100%, 70%, and 30%, respectively.

[0026] The present invention will be described in detail below.

[0027] As mentioned above, since the light-emitting medium layer of the organic light-emitting device is composed of organic materials, it is easily deteriorated by moisture, oxygen, heat, etc. in the atmosphere. This deterioration attenuates the light-emitting performance of the organic light-emitting device, which easily causes a deterioration in display characteristics. Therefore, in order to prevent deterioration of the organic light-emitting device, a structure is adopted in which the top of the organic light-emitting device formed on the glass substrate is covered with a glass substrate (glass cover), the inside is made into a hollow structure, and an adsorbent for moisture, etc., is placed inside the hollow structure. In addition, a structure in which an epoxy resin with low moisture permeability is filled in the hollow space between two glass substrates and the entire organic light-emitting device is sealed has also been proposed.

[0028] However, in a structure where an adsorption desiccant is placed in a hollow space within a glass cover, the desiccant's absorption capacity is insufficient, so the desiccant cannot sufficiently suppress deterioration of the organic light-emitting element. In addition, in a method of filling and sealing the hollow space with an epoxy resin, there is a concern that deterioration of the organic light-emitting element may occur due to insufficient management of the moisture content of the epoxy resin, and because the curing temperature of the epoxy resin is high, there is a problem that the organic light-emitting element deteriorates due to the heat applied during curing.

[0029] Encapsulating materials used in the manufacturing process of organic light-emitting devices are exposed to special environments such as vacuum and curing, and must maintain long-term stability. Therefore, it is crucial to manage the purity of the encapsulating material and control the curing speed. Furthermore, during the encapsulating process of organic light-emitting devices, the encapsulating material composition must be cured at an appropriate curing temperature and time. Since the encapsulating material can easily affect the light-emitting layer of the organic light-emitting device, the fewer impurities such as moisture, ions, and low-molecular weight contaminants, the more desirable it is.

[0030] Accordingly, the present invention aims to provide a composition for manufacturing an encapsulant, which can improve the lifespan of an organic light-emitting device, effectively block oxygen and moisture from the outside, and produce an encapsulant with minimized ionic impurities. Furthermore, the present invention aims to provide a curable encapsulant composition that can ensure process stability during post-processing by introducing a curable system, and an encapsulant using the same.

[0031] According to one embodiment of the present invention, a sealing composition comprises: 1) a polyorganosiloxane having an average of 0.5 or more alkenyl groups bonded to silicon atoms per molecule; 2) a polyorganohydrogensiloxane having an average of 2 or more hydrogen atoms bonded to silicon atoms per molecule; 3) a hydrosilylation catalyst; and 4) a reaction inhibitor comprising a compound having at least two unsaturated ethylene groups, wherein the content of the reaction inhibitor is 0.005 wt% to 1.2 wt% based on the total weight of the polyorganosiloxane. In addition, the content of ions other than platinum group element ions of the sealing composition is 50 ppm or less based on the total weight of the sealing composition.

[0032] Encapsulant for organic light-emitting devices must not affect the movement of electrons and holes. For example, a representative material included in the electron transport layer located between the cathode and the light-emitting layer is Alq3 (Tris(8-hydroxyquinoline)aluminum). This material can undergo oxidation or reduction reactions when it encounters ions with higher ionization energies or higher electronegativity. This can lead to a decrease in the luminous efficiency and lifespan of the organic light-emitting device. Therefore, the encapsulant must also not affect these substances.

[0033] Furthermore, a silver:magnesium alloy is typically used as the cathode positioned on the organic layer of an organic light-emitting device. This alloy has a low work function, facilitating electron injection, but can easily oxidize by reacting with moisture, oxygen, and ions in the air or the sealing material. Therefore, the sealing material in contact with the cathode must be composed of a material that has high airtightness to prevent oxidation and corrosion of the silver:magnesium cathode, while not affecting the electron injection characteristics of the cathode.

[0034] Accordingly, in the present invention, the ion content of the encapsulating composition is adjusted to the above range. If the content of ions other than platinum group element ions exceeds 50 ppm based on the total weight of the encapsulating composition, there is a high risk that when the composition is encapsulated using the encapsulating composition, the electrodes and organic layer materials of the organic light-emitting device will react with the ions contained in the encapsulating composition, resulting in a deterioration in performance.

[0035] Specifically, the content of ions other than platinum group element ions may be 30 ppm or less, and preferably 20 ppm or less, based on the total weight of the encapsulating composition.

[0036] The content of ions in the above-mentioned sealing composition can be measured through ICP-OES (Inductively Coupled Plasma Optical Emission Spectroscopy) analysis and IC (Ion Chromatography). Specifically, the content of metal ions and heavy metal ions can be measured through ICP-OES analysis, and the content of halogen ions, sulfur ions, and phosphorus ions can be measured through IC analysis, and the content of the ions refers to the total amount of these ions.

[0037] Specifically, the ions other than the platinum group element ions may be metal ions, heavy metal ions, halogen ions, sulfur ions, and phosphorus ions other than the platinum group, and more specifically, may be lithium (Li) ions, sodium (Na) ions, magnesium (Mg) ions, aluminum (Al) ions, potassium (K) ions, calcium (Ca) ions, chromium (Cr) ions, manganese (Mn) ions, iron (Fe) ions, cobalt (Co) ions, nickel (Ni) ions, copper (Cu) ions, zinc (Zn) ions, gallium (Ga) ions, zirconium (Zr) ions, silver (Ag) ions, cadmium (Cd) ions, barium (Ba) ions, titanium (Ti) ions, lead (Pb) ions, bismuth (Bi) ions, fluorine (F) ions, chlorine (Cl) ions, bromine (Br) ions, iodine (I) ions, sulfur (S) ions, and phosphorus (P) ions. The oxidation number of the above ion is not particularly limited.

[0038] In the case of platinum group element ions, since they originate from the platinum-based catalyst and are not free ions, they have little effect on the performance of the organic light-emitting device and are therefore not included in the ion content of the present invention. Specifically, most catalysts have a chelate structure in which metal ions are surrounded by organic ligands, and in such a stable structure, the metal ions are not exposed to the outside, so the metal ions liberated from the catalyst do not exist freely in the composition. In the present invention, the ion content in the composition is controlled to minimize the effect of free ions on the performance of the organic light-emitting device, and therefore, the content of ions originating from the catalyst is unnecessary to be reflected.

[0039] The content of ions in the above composition can be achieved by performing a purification process on the polyorganosiloxane before mixing and kneading. Specifically, the purification process can be activated soil treatment, activated carbon treatment, ion adsorption, or ion exchange, and more particularly, activated soil treatment. The activated soil treatment can be performed by mixing the polyorganosiloxane with xylene, adding activated soil, heating, then cooling it to room temperature again, and removing the activated soil and xylene. The activated soil may be bentonite, but is not particularly limited. The sealing material composition according to one embodiment of the present invention includes a polyorganosiloxane having an average of 0.5 or more alkenyl groups bonded to silicon atoms per molecule. The polyorganosiloxane may include an average of 0.5 or more alkenyl groups bonded to silicon atoms per molecule, preferably an average of 0.6 or more, and more preferably an average of 2 or more alkenyl groups bonded to silicon atoms per molecule. However, the upper limit is not particularly limited.

[0040] The viscosity of the above polyorganosiloxane may be 10 mPa·s to 1,000,000 mPa·s at 23°C, may be 100 mPa·s to 1,000,000 mPa·s, or may be 1,000 mPa·s to 100,000 mPa·s. Considering the mechanical strength after curing, the viscosity of the above polyorganosiloxane is preferably 10 mPa·s or more. However, in order to improve the workability of the sealing material, it is preferably 1,000,000 mPa·s or less.

[0041] In one embodiment of the present invention, the polyorganosiloxane may be represented by the following chemical formula 1.

[0042] [Chemical Formula 1]

[0043] (R 1a R 2a R 3a SiO 1 / 2 ) aa (R 4a R 5a SiO 2 / 2 ) ba (R 6a SiO 3 / 2 ) ca (SiO 4 / 2 ) da

[0044] In the above chemical formula 1,

[0045] R 1a Inland R 6a are the same or different from each other, and each independently represents an alkyl group, an alkoxy group, an aryl group, a silanol group, or an alkenyl group, which are substituted or unsubstituted with halogen,

[0046] R 1a , and R 4a Inland R 6a At least one of them is an alkenyl group,

[0047] aa, ba, ca and da are the repetition numbers of each unit, and aa, ca and da are real numbers from 0 to 100, respectively, but aa+ca+da≥1.

[0048] ba is a real number between 1 and 2,000,

[0049] If each of aa, ba, ca, and da is 2 or more, the plural units are equal or different from each other.

[0050] In one embodiment of the present invention, the R 1a , and R 4a Inland R 6a At least one of them may be vinyl.

[0051] In one embodiment of the present invention, the R 1a , and R 4a Inland R 6a At least two of them may be alkenyl groups, preferably vinyl groups.

[0052] In one embodiment of the present invention, the R 1a , and R 4a Inland R 6a The rest except the alkenyl group and R 2a and R 3a are the same or different from each other, and each can independently be an alkyl group, preferably a C1 to C5 alkyl group, and more preferably a methyl group.

[0053] In one embodiment of the present invention, aa and ca may each be real numbers from 1 to 100.

[0054] In one embodiment of the present invention, the ba may be a real number of 100 to 1,800, preferably a real number of 200 to 1,500.

[0055] In one embodiment of the present invention, the weight average molecular weight (Mw) of the polyorganosiloxane may be 1,000 to 100,000, specifically 5,000 to 80,000, and more specifically 10,000 to 50,000.

[0056] The above polyorganosiloxane is preferably a material that has undergone a purification process capable of reducing the ion content. The purification process may be activated soil treatment, activated carbon treatment, ion adsorption, ion exchange, or the like.

[0057] The ions in the above polyorganosiloxane may be metal ions, heavy metal ions, halogen ions, sulfur ions, and phosphorus ions, and the oxidation number of the ions is not particularly limited. Specific examples include, but are not limited to, lithium (Li) ions, sodium (Na) ions, magnesium (Mg) ions, aluminum (Al) ions, potassium (K) ions, calcium (Ca) ions, chromium (Cr) ions, manganese (Mn) ions, iron (Fe) ions, cobalt (Co) ions, nickel (Ni) ions, copper (Cu) ions, zinc (Zn) ions, gallium (Ga) ions, zirconium (Zr) ions, silver (Ag) ions, cadmium (Cd) ions, barium (Ba) ions, titanium (Ti) ions, lead (Pb) ions, bismuth (Bi) ions, fluorine (F) ions, chlorine (Cl) ions, bromine (Br) ions, iodine (I) ions, sulfur (S) ions, and phosphorus (P) ions.

[0058] The above-mentioned encapsulating composition may contain one or more types or two or more types of polyorganosiloxane.

[0059] A sealing composition according to one embodiment of the present invention comprises a polyorganohydrogensiloxane having an average of two or more hydrogen atoms bonded to silicon atoms per molecule. The polyorganohydrogensiloxane can function as a crosslinking agent.

[0060] The above polyorganohydrogensiloxane may have an average of 2 or more, preferably an average of 3 or more, and more preferably an average of 10 or more hydrogen atoms bonded to silicon atoms per molecule, but the upper limit is not particularly limited. The hydrogen atoms bonded to the silicon atoms may be located at the terminal of the molecular chain, in the middle of the molecular chain, or at both the terminal and the middle of the molecular chain.

[0061] The viscosity of the above polyorganohydrogen may be 5,000 mPa·s or less, specifically 1 mPa·s to 1,000 mPa·s, and more specifically 1 mPa·s to 100 mPa·s at 23°C.

[0062] The above polyorganohydrogensiloxane may be used in an amount such that the ratio of the average number of hydrogen atoms bonded to silicon atoms in one molecule of the polyorganohydrogensiloxane to the average number of alkenyl groups bonded to silicon atoms in one molecule of the polyorganohydrogensiloxane (Si-H / Si-alkenyl) is 0.2 to 20, specifically, 0.5 to 15, and more specifically, 5 to 12. When the Si-H / Si-alkenyl is 0.2 or more, it is preferable in that sufficient crosslinking can be obtained. However, in order to minimize unreacted -SiH and stably implement the physical properties of the cured product, it is preferable that it is 20 or less.

[0063] In one embodiment of the present invention, the polyorganohydrogensiloxane can be represented by the following chemical formula 2.

[0064] [Chemical Formula 2]

[0065] (R 1b R 2b R 3b SiO 1 / 2 ) ab (R 4b R 5b SiO 2 / 2 ) bb (R 6bSiO 3 / 2 ) cb (SiO 4 / 2 ) db

[0066] In the above chemical formula 2,

[0067] R 1b Inland R 6b are the same or different from each other, and each independently represents an alkyl group, an alkoxy group, an aryl group or a silanol group, which are substituted or unsubstituted with halogen,

[0068] R 1b , and R 4b Inland R 6b At least one of them is hydrogen,

[0069] ab, bb, cb and db are the repetition numbers of each unit, and ab, cb and db are real numbers from 0 to 100, respectively, but ab+cb+db≥1.

[0070] bb is a real number between 1 and 1,000,

[0071] If each of aa, ba, ca, and da is 2 or more, the plural units are equal or different from each other.

[0072] In one embodiment of the present invention, the R 1b , and R 4b Inland R 6b The rest except for hydrogen and R 2b and R 3b are the same or different from each other, and each can independently be an alkyl group, preferably a C1 to C5 alkyl group, more preferably a methyl group.

[0073] In one embodiment of the present invention, ab and cb may each be real numbers from 1 to 100.

[0074] In one embodiment of the present invention, bb may be a real number of 5 to 500, preferably a real number of 10 to 100.

[0075] In one embodiment of the present invention, when the bb is 2 or more, a plurality of R 4b R 5b SiO 2 / 2 are the same or different from each other. For example, HMeSiO 2 / 2 Unit and Me2SiO 2 / 2 The units can coexist. In the present invention, Me means a methyl group and Vi means a vinyl group.

[0076] In one embodiment of the present invention, the weight average molecular weight (Mw) of the polyorganohydrogensiloxane may be 100 to 10,000, specifically 500 to 8,000, and more specifically 1,000 to 5,000.

[0077] In one embodiment of the present invention, the content of the polyorganohydrogensiloxane may be 0.1 wt% to 20 wt%, specifically 0.5 wt% to 15 wt%, and more specifically 1 wt% to 10 wt%, based on the total weight of the polyorganosiloxane. When the content of the polyorganohydrogensiloxane is 0.1 wt% or more, it is preferable in that sufficient crosslinking can be obtained. However, in order to minimize unreacted -SiH and stably implement the physical properties of the cured product, it is preferable that it is 20 wt% or less.

[0078] The above-mentioned encapsulating composition may contain one or more types or two or more types of polyorganohydrogensiloxane.

[0079] In one embodiment of the present invention, the alkyl group may be linear, branched or cyclic, and the number of carbon atoms is not particularly limited, but is preferably 1 to 30. Specific examples include methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethyl-butyl, pentyl, n-pentyl, cyclopentyl, isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, cyclohexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, n-heptyl, 1-methylhexyl, cyclopentylmethyl, cyclohexylmethyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, Examples thereof include, but are not limited to, 2-propylpentyl group, n-nonyl group, 2,2-dimethylheptyl group, 1-ethyl-propyl group, 1,1-dimethyl-propyl group, isohexyl group, 2-methylpentyl group, 4-methylhexyl group, and 5-methylhexyl group.

[0080] The above aryl group may be monocyclic or polycyclic, and the number of carbon atoms is not particularly limited, but is preferably 6 to 30 carbon atoms. Specific examples include, but are not limited to, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a triphenylenyl group, anthracenyl group, a phenanthryl group, a pyrenyl group, a perylenyl group, a chrysenyl group, a fluorenyl group, and the like.

[0081] The above halogen group can be fluorine, chlorine, bromine or iodine.

[0082] The alkoxy group may be linear, branched, or cyclic. The carbon number of the alkoxy group is not particularly limited, but is preferably 1 to 20 carbon atoms. Specifically, it may be a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a tert-butoxy group, a sec-butoxy group, an n-pentyloxy group, a neopentyloxy group, an isopentyloxy group, an n-hexyloxy group, a 3,3-dimethylbutyloxy group, a 2-ethylbutyloxy group, an n-octyloxy group, an n-nonyloxy group, an n-decyloxy group, a benzyloxy group, a p-methylbenzyloxy group, etc., but is not limited thereto.

[0083] The above alkenyl group may be linear or branched, and the number of carbon atoms is not particularly limited, but is preferably 2 to 40. Specific examples include, but are not limited to, a vinyl group, a 1-propenyl group, an isopropenyl group, a 1-butenyl group, a 2-butenyl group, a 3-butenyl group, a 1-pentenyl group, a 2-pentenyl group, a 3-pentenyl group, a 3-methyl-1-butenyl group, a 1,3-butadienyl group, an allyl group, a 1-phenylvinyl-1-yl group, a 2-phenylvinyl-1-yl group, a 2,2-diphenylvinyl-1-yl group, a 2-phenyl-2-(naphthyl-1-yl)vinyl-1-yl group, a 2,2-bis(diphenyl-1-yl)vinyl-1-yl group, a stilbenyl group, and a styrenyl group.

[0084] A sealing composition according to one embodiment of the present invention includes a hydrosilylation catalyst.

[0085] In one embodiment of the present invention, the hydrosilylation catalyst is a catalyst for a hydrosilylation reaction for promoting curing of the composition. The hydrosilylation catalyst may be a platinum group element catalyst or a platinum group element compound, and specifically may include at least one selected from the group consisting of a platinum-based catalyst, a rhodium-based catalyst, and a palladium-based catalyst, and more specifically may include at least one selected from the group consisting of ruthenium, rhodium, palladium, osmium, iridium, platinum, and complexes thereof. In particular, in terms of significantly promoting curing of the present composition, the hydrosilylation catalyst is preferably a platinum-based catalyst. The platinum-based catalyst may be a platinum fine powder; platinum black; chloroplatinic acid; an alcohol modified product of chloroplatinic acid; a complex of chloroplatinic acid and a diolefin; The hydrosilylation catalyst may be at least one selected from the group consisting of platinum-olefin complexes; platinum-carbonyl complexes such as platinum bis(acetoacetate) and platinum bis(acetylacetonate); chloroplatinic acid-alkenylsiloxane complexes such as chloroplatinic acid-divinyltetramethyldisiloxane complexes and chloroplatinic acid-tetravinyltetramethylcyclotetrasiloxane complexes; platinum-alkenylsiloxane complexes such as platinum divinyltetramethyldisiloxane complexes and platinum-tetravinyltetramethylcyclotetrasiloxane complexes; and complexes of chloroplatinic acid and acetylene alcohols. In particular, the hydrosilylation catalyst is preferably a platinum-alkenylsiloxane complex, in which case curing of the composition can be promoted.

[0086] The content of the metal element in the hydrosilylation catalyst may be 0.1 ppm to 100 ppm, preferably 1 ppm to 50 ppm, and more preferably 5 ppm to 20 ppm, based on the total weight of the encapsulating composition.

[0087] A sealing composition according to one embodiment of the present invention comprises a reaction inhibitor comprising a compound having at least two unsaturated ethylene groups. The reaction inhibitor can extend the usable life at room temperature and improve storage stability.

[0088] The above reaction inhibitor may include at least one selected from the group consisting of diallyl phthalate, diallyl maleate, diallyl oxalate, and tri-allyl isocyanurate.

[0089] U.S. Patent No. 8,304,991 and Japanese Patent No. 5,619,383 describe 3,5-dimethyl-1-hexyn-3-ol, 2-methyl-3-hexyn-2-ol, 1-ethynyl-1-cyclohexanol, 3-methyl-3-pentene-1-yne, 3,5-dimethyl-3-hexene-1-yne, methylvinylsiloxane cyclic compounds, organic nitrogen compounds, organic phosphorous compounds, etc. as reaction inhibitors applicable to sealing compositions. However, the reaction inhibitors described in the above-described U.S. and Japanese patents have low weight-average molecular weights and high volatility, making them difficult to apply to encapsulant compositions in the commercial manufacturing process of actual organic light-emitting devices. For this reason, no reaction inhibitors were used in the encapsulant compositions in the specific examples of the above-described U.S. and Japanese patents.

[0090] The present inventors have found that, as a reaction inhibitor applied to a sealing material composition, a reaction inhibitor including a compound having at least two unsaturated ethylene groups, such as the present invention, particularly diallyl phthalate, diallyl maleate, diallyl oxalate, tri-allyl isocyanurate, etc., has a relatively large weight average molecular weight and low volatility compared to conventional reaction inhibitors, and thus has little effect on organic light-emitting devices.

[0091] In one embodiment of the present invention, the content of the reaction inhibitor may be 0.005 wt% to 1.2 wt%, specifically 0.01 wt% to 1.0 wt%, and more specifically 0.10 wt% to 0.70 wt%, based on the total weight of the polyorganosiloxane. When the content of the reaction inhibitor is less than 0.005 wt%, the effect of reaction inhibition is insufficient, so the reaction rate may not be controlled, and thus a problem may occur due to reaction before covering the entire large-area designed area in the encapsulation process step of the organic light-emitting device, which is not preferable. In addition, when the content of the reaction inhibitor exceeds 1.2 wt%, the content of the reaction inhibitor having a relatively small weight average molecular weight compared to the polyorganosiloxane is included in excess, which may affect the light-emitting material, and thus the light-emitting efficiency of the organic light-emitting device may be significantly reduced, which is not preferable.

[0092] In particular, when the encapsulating composition does not include a reaction inhibitor such as the present invention, there may not be a problem with the effective pixel area ratio of the organic light-emitting device, but as the area of ​​the organic light-emitting device increases, the problem of non-filling of the encapsulating composition may occur more widely and more frequently, and accordingly, the defect rate of organic light-emitting becomes higher, which is not desirable.

[0093] Accordingly, the encapsulating composition according to one embodiment of the present invention can maintain good curing reactivity and storage stability by including a reaction inhibitor including a compound having at least two unsaturated ethylene groups, particularly one or more reaction inhibitors selected from among diallyl phthalate, diallyl maleate, diallyl oxalate, and tri-allyl isocyanurate, in a specific content range, and thus can exhibit a characteristic of maintaining the effective pixel area of ​​an organic light-emitting device without decreasing even after a long-term test of storing at 85°C for 500 hours.

[0094] In one embodiment of the present invention, the encapsulating composition is an addition reaction curable composition that is liquid at room temperature. The encapsulating composition comprises the aforementioned polyorganosiloxane, polyorganohydrogensiloxane, hydrosilylation catalyst, and reaction inhibitor as basic components, and optionally may include fillers, flame retardants, heat resistance improvers, adhesive agents, thixotropic agents, pigments, plasticizers, and the like, as long as the purpose of the present invention is not impaired.

[0095] Examples of the filler include silica, titanium oxide, etc. The blending amount of the filler is preferably within a range that maintains good workability and does not impair the properties of the cured product, and is preferably 1 to 50 parts by weight per 100 parts by weight of the polyorganosiloxane.

[0096] In one embodiment of the present invention, the sealing material composition can be manufactured by adding polyorganosiloxane, a hydrosilylation catalyst, a reaction inhibitor, and other optional components to the polyorganosiloxane, and mixing the mixture using a known mixer at room temperature or, if necessary, while heating (for example, at 80°C to 200°C). A known device equipped with a heating means or a cooling means can be used as the mixer.

[0097] In one embodiment of the present invention, the encapsulating composition may have a curing temperature of room temperature (typically 23°C) or higher and 100°C or lower. If the curing temperature of the encapsulating composition is lower than room temperature, curing may take time, which may result in poor workability. Furthermore, if the curing temperature of the encapsulating composition exceeds 100°C, the organic light-emitting element is likely to deteriorate due to heat during curing, and there is a high risk that the effective pixel area of ​​the organic light-emitting element may decrease.

[0098] The moisture content of the encapsulating composition may be 400 ppm or less, 300 ppm or less, 200 ppm or less, or 120 ppm or less, or 10 ppm or more, 50 ppm or more, 80 ppm or more, or 100 ppm or more, based on the total weight of the encapsulating composition. When encapsulating an organic light-emitting device using a composition having a moisture content of 400 ppm or less, it is preferable in terms of preventing the organic light-emitting device from being deteriorated by moisture generated.

[0099] To control the moisture content in the encapsulating composition within the above range, a method may be adopted in which at least one of the polyorganosiloxane and the polyorganohydrogensiloxane is heated while controlling the temperature and time prior to mixing and kneading. In particular, a method in which the polyorganosiloxane is heated under reduced pressure is preferably adopted. That is, it is preferable to heat the polyorganosiloxane while reducing the pressure as necessary, and to evaporate and vaporize the moisture in the polyorganosiloxane, thereby adjusting the moisture content in the composition to 400 ppm or less. Furthermore, as long as the moisture content in the resulting composition can be suppressed to 400 ppm or less, it is also possible to add water to the resulting composition after mixing the heat-treated polyorganosiloxane with other components.

[0100] In addition, it is preferable that the above-mentioned encapsulating composition has a viscosity of 10 mPa·s to 1,000,000 mPa·s at 23°C.

[0101] The present invention also provides an encapsulant for an organic light-emitting device, which is a cured product of the encapsulant composition. The encapsulant is characterized in that it is manufactured using the encapsulant composition. The encapsulant according to one embodiment of the present invention can be formed using any method known in the art, except for using the encapsulant composition described above. More specifically, the encapsulant composition can be formed using methods such as application, coating, and printing on a substrate, but is not limited thereto.

[0102] The sealing composition according to one embodiment of the present invention can be cured by heating at a temperature of 23°C or higher and 100°C or lower, more specifically 70°C to 95°C, for 5 to 120 minutes (for example, 90°C for 60 minutes). Since it is cured within the allowable temperature range of an organic light-emitting device (organic EL device) (100°C or lower), it can be suitably used as a sealing material for sealing an organic EL device. The molding, curing method, curing conditions, etc. of the composition can be applied to known methods and conditions.

[0103] A sealing composition according to one embodiment of the present invention has the characteristics of being able to produce a sealing material that can improve the lifespan of an organic light-emitting device and effectively block oxygen and moisture, etc., from entering from the outside.

[0104]

[0105] *The encapsulating material according to one embodiment of the present invention can be effective in protecting an organic light-emitting element that is sensitive to moisture or humidity.

[0106] The present invention provides a method for encapsulating an organic light-emitting device, comprising the steps of applying the aforementioned encapsulating composition onto the organic light-emitting device; and curing the applied encapsulating composition at 23°C to 100°C.

[0107] The organic light-emitting device may be provided in a conventional configuration known in the art, except that it is encapsulated with the above-described material. For example, glass, metal, or polymer films commonly used in the art may be used as the lower and / or upper substrates. In addition, the organic light-emitting device may include, for example, a pair of electrodes and a layer of an organic material formed between the pair of electrodes. Here, one of the pair of electrodes may be configured as a transparent electrode. In addition, the layer of the organic material may include, for example, a hole transport layer, a light-emitting layer, and an electron transport layer.

[0108] Hereinafter, the present specification will be described in more detail through examples. However, the following examples are intended only to illustrate the present specification and are not intended to limit the present specification.

[0109] <Example>

[0110] <Example 1>

[0111] First, polydimethylsiloxane having a viscosity of 3,000 mPa·s at 23°C and having both molecular terminals blocked with dimethylvinylsiloxy groups was treated with activated soil as follows. 100 parts by weight of the polydimethylsiloxane was mixed with 75 parts by weight of xylene, and then 5 parts by weight of bentonite (Cas no. 70131-50-9) was added, the temperature was raised to 145°C, and heated for 2 hours under a nitrogen atmosphere. After cooling to room temperature, the activated soil was removed through filtration, and the filtered solution was heated again at 150°C and xylene was removed under a vacuum.

[0112] 100 parts by weight of polydimethylsiloxane treated with activated soil in this way was heat-treated at a temperature of 150°C for 2 hours while reducing the pressure to 10 mmHg. To 100 parts by weight of the heated polydimethylsiloxane, 1.5 parts by weight of polymethylhydrogensiloxane having a hydroxyl group in the side chain at a ratio of 50 mol%, a platinum-based catalyst, and a reaction inhibitor shown in Table 1 below were added, and the mixture was uniformly mixed at room temperature and then dispersed to prepare a composition. At this time, the platinum-based catalyst was added in an amount such that the weight of platinum was 10 ppm based on the total weight of the composition. In addition, the molar ratio of the Si-H group of the polymethylhydrogensiloxane to the Si-Vi group of the polydimethylsiloxane (Si-H / Si-Vi) was set to 10.

[0113] The specific properties of each material used are listed in Table 2 below.

[0114]

[0115] <Examples 2 to 5 and Comparative Examples 1 to 5>

[0116] A packaging material composition was manufactured in the same manner as in Example 1, except that the components listed in Table 1 below were used.

[0117]

[0118] <Example 6>

[0119] A packaging material composition was prepared in the same manner as in Example 1 above, and then the prepared composition was left in a chamber set at a temperature of 25°C and a moisture content of 100% for 1 hour.

[0120]

[0121] <Examples 7 and 8>

[0122] The encapsulating compositions of Examples 7 and 8 were manufactured in the same manner as in Example 1, except that bentonite was added when treating polydimethylsiloxane with activated soil and the heating temperature and time under a nitrogen atmosphere were changed to 150°C for 1 hour and 30 minutes and 150°C for 2 hours, respectively.

[0123]

[0124] Comparative Examples 6 to 8

[0125] Encapsulating compositions of Comparative Examples 6, 7, and 8 were prepared in the same manner as in Example 1, except that bentonite was added when treating polydimethylsiloxane with activated soil, and the heating temperature and time performed under a nitrogen atmosphere were changed to 150°C for 1 hour, 100°C for 1 hour, and 100°C for 2 hours, respectively.

[0126] Content of componentsPolyorganosiloxanePolyorganohydrogensiloxanePlatinum-based catalyst (platinum amount)Reaction inhibitorTypeContentExample 1100 parts by weight1.5 parts by weight10 ppmD-10.50 parts by weightExample 2100 parts by weight1.5 parts by weight10 ppmD-20.50 parts by weightExample 3100 parts by weight1.5 parts by weight10 ppmD-30.50 parts by weightExample 4100 parts by weight1.5 parts by weight10 ppmD-10.01 parts by weightExample 5100 parts by weight1.5 parts by weight10 ppmD-11.00 parts by weightExample 6100 parts by weight1.5 parts by weight10 ppmD-10.50 parts by weightExample 7100 parts by weight1.5 parts by weight10 ppmD-10.50 parts by weightExample 8100 Part by weight 1.5 part by weight 10 ppmD-10.50 Part by weight Comparison Example 1100 Part by weight 1.5 part by weight 10 ppmD-40.50 Part by weight Comparison Example 2100 Part by weight 1.5 part by weight 10 ppmD-11.50 Part by weight Comparison Example 3100 Part by weight 1.5 part by weight 10 ppmD-12.00 Part by weight Comparison Example 4100 Part by weight 1.5 part by weight 10 ppmD-15.00 Part by weight Comparison Example 5100 Part by weight 1.5 part by weight 10 ppm--Comparison Example 6100 Part by weight 1.5 part by weight 10 ppmD-10.50 Part by weight Comparison Example 7100 Part by weight 1.5 part by weight 10 ppmD-10.50 Part by weight Comparison Example 8100 Part by weight 1.5 part by weight 10 ppmD-10.50 Part by weight

[0127] Polydimethylsiloxane Average number of silicon atom-bonded vinyl (Si-Vi) groups per molecule: 2 Viscosity: 3,000 mPa·s (23℃) Weight average molecular weight (Mw): 24,000 Chemical formula: (Vi1Me2SiO 1 / 2 )1(Me2SiO 2 / 2 ) x (Vi1Me2SiO 1 / 2 )1(x=300 ~ 400) Average number of silicon atom-bonded hydrogen (Si-H) groups per polymethyl hydrogen siloxane molecule: 20 Viscosity: 30 mPa·s(23℃) Weight average molecular weight (Mw): 2,800 Chemical formula: (Me2SiO 1 / 2 )1(HMeSiO 2 / 2 ) y (Me2SiO 2 / 2 ) z (Me2SiO 1 / 2 )1(y=20 ~ 30, z=15 ~ 25)Platinum catalystChloroplatinic acid vinylsiloxane complex compoundD-1Diallyl maleate (Mw: 196.20l)D-2Diallyl phthalate (Mw: 246.26)D-3Triallyl isocyanurate (Mw: 249.27)D-41-ethynyl-1-cyclohexanol (Mw: 124.18)

[0128]

[0129] <Experimental Example 1: Measurement of Ion Content>

[0130] Based on the total weight of the sealing material compositions of Examples 1 to 8 and Comparative Examples 1 to 8, the content of ions other than platinum group element ions was analyzed through ICP-OES and IC as follows, and is shown in Table 3 below.

[0131] * ICP-OES (Inductively Coupled Plasma Optical Emission Spectroscopy):

[0132] The above-mentioned encapsulating composition was pretreated according to EPA standards (US Environmental Protection Agency) for ICP-OES analysis. The specific standard number is EPA 3052: 1996.

[0133] Additionally, the pretreated composition was analyzed by ICP-OES, and the analysis was conducted according to EPA standards. The specific standard number is EPA 6010D: 2018.

[0134] * IC (Ion Chromatography):

[0135] The above-mentioned encapsulating composition was subjected to IC analysis, and the analysis was conducted according to the BS standard (British Standards). The specific standard number is BS EN 14582:2016.

[0136]

[0137] <Experimental Example 2: Moisture Content Measurement>

[0138] The moisture content included in the encapsulating compositions of Examples 1 to 8 and Comparative Examples 1 to 8 was measured using a Karl Fischer device from Mitsubishi according to the ASTM E1064 standard, and the results are shown in Table 3 below.

[0139] Experimental Example 1 Experimental Example 2 Ion Content (ppm) Moisture Content (ppm) Example 1 50 100 Example 2 48 100 Example 3 49 100 Example 4 50 100 Example 5 50 100 Example 6 49 400 Example 7 29 400 Example 8 20 400 Comparative Example 150 100 Comparative Example 250 100 Comparative Example 350 100 Comparative Example 4 49 100 Comparative Example 5 48 100 Comparative Example 6 65 100 Comparative Example 7 10 2 100 Comparative Example 8 28 5 100

[0140]

[0141] <Experimental Example 3: Gel Time Measurement>

[0142] The behavior of storage modulus and loss modulus was confirmed while applying heat to each of the encapsulating compositions of Example 1 and Comparative Example 5 to cure them, and the time when the storage modulus and loss modulus were the same was reported as gel time and is listed in Table 4 below. The measurement conditions for the storage modulus and loss modulus are as follows.

[0143] - Device: Anton Paar rheometer

[0144] - Temperature: 90℃

[0145] - Frequency: 1Hz

[0146] - Strain(γ): 1%

[0147] - Measurement Gap: 0.3mm

[0148] Gel time (min) Example 130 Comparative example 55

[0149] Before the gel time, it exhibits the characteristics of a viscous (liquid) with a high loss modulus, and after the gel time, it exhibits the characteristics of an elastic (solid) with a high storage modulus. That is, the encapsulating composition according to Example 1 has a longer gel time than the encapsulating composition according to Comparative Example 5, i.e., a slower curing speed, and therefore is more preferable in terms of securing working time and improving coating uniformity.

[0150]

[0151] <Experimental Example 4: Evaluation of Effective Pixel Area Ratio>

[0152] The sealing of organic EL devices was performed using the encapsulant compositions obtained in Examples 1 to 8 and Comparative Examples 1 to 8. First, an organic EL device was manufactured. That is, a pattern of an ITO film (thickness 150 nm) as a first electrode layer was formed by sputtering on a glass substrate, and then a mixture of poly(3,4-ethylenedioxythiophene) and polystyrenesulfonic acid (thickness 20 nm) was spin-coated as a hole-transport layer, and poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylenevinylene] (MEHPPV) (thickness 100 nm) was formed as a light-emitting layer, respectively. Unnecessary parts were removed using methanol for the hole-transport layer, and toluene for the light-emitting layer, and a pattern of an organic light-emitting medium layer was formed. Subsequently, a Ca film (thickness 5 nm) and an Al film (thickness 150 nm) were laminated and formed as a second electrode layer by a vapor deposition method. Additionally, a silicon nitride film (500 nm) was formed as a barrier layer (protective layer) using the plasma CVD method.

[0153] The encapsulating compositions obtained in Examples 1 to 8 and Comparative Examples 1 to 8 were respectively applied onto the organic EL elements thus obtained, a glass cover was attached, and then heat was applied at 90°C for 60 minutes to cure. The effective pixel area ratio of the organic EL elements was obtained using optical equipment for the organic EL panels thus manufactured.

[0154] Additionally, a long-term test was conducted at 85°C for 500 hours, and the effective pixel area ratio was obtained using the same equipment. The results are shown in Table 5 below.

[0155] Figure 1 shows examples where the effective pixel area ratios are 100%, 70%, and 30%, respectively.

[0156] Effective pixel area ratio (%) Initial Long-term test After Example 1100100 Example 2100100 Example 3100100 Example 4100100 Example 510099 Example 610099 Example 7100100 Example 8100100 Comparative Example 110090 Comparative Example 210090 Comparative Example 310070 Comparative Example 410030 Comparative Example 6100100 Comparative Example 710095 Comparative Example 810050

[0157] As shown in the results of Table 5 above, the encapsulating composition according to one embodiment of the present invention includes a reaction inhibitor including a compound having at least two unsaturated ethylene groups, particularly one or more reaction inhibitors selected from among diallyl phthalate, diallyl maleate, diallyl oxalate, and tri-allyl isocyanurate, in a specific content range, and since the ion content in the composition is controlled to 50 ppm or less, the curing reactivity and storage stability can be maintained well, and accordingly, the effective pixel area of ​​the organic light-emitting device can be maintained without decreasing even after a long-term test of storing at 85°C for 500 hours. In addition, when comparing Examples 6 to 8, which have the same moisture content of 400 ppm, it can be confirmed that when the ion content is controlled to 30 ppm or less, the effective pixel area ratio is maintained at 100%, similar to Example 1, which has a moisture content of 100 ppm.

[0158]

[0159] <Experimental Example 5: Luminescence Efficiency Evaluation>

[0160] The encapsulating compositions obtained in Example 1 and Comparative Examples 6 to 8 were applied onto organic EL devices using the same process as in Experimental Example 4 to obtain organic EL panels. The luminous efficiency of the organic EL devices was then measured using optical equipment. Furthermore, a long-term test was conducted, in which the devices were stored at 85°C for 500 hours, after which the luminous efficiency was measured using the same equipment. The measured results are shown in Table 6 below.

[0161] Figure 2 shows examples of luminous efficiencies of 100%, 70%, and 30%, respectively.

[0162] Luminous Efficiency (%) After Initial Long-Term Test Example 1100100Comparative Example 610090Comparative Example 710070Comparative Example 810030

[0163] Through the results in Table 6 above, it can be confirmed that when the ion content in the composition exceeds 50 ppm, not only the effective pixel area but also the luminous efficiency is reduced.

Claims

1. 1) Polyorganosiloxane having an average of 0.5 or more alkenyl groups bonded to silicon atoms in one molecule; 2) Polyorganohydrogensiloxane having an average of two or more hydrogen atoms bonded to silicon atoms in one molecule; 3) hydrosilylation catalyst; and 4) A sealing composition comprising a reaction inhibitor comprising a compound having at least two unsaturated ethylene groups, Based on the total weight of the polyorganosiloxane, the content of the reaction inhibitor is 0.005 wt% to 1.2 wt%, An encapsulating composition for an organic light-emitting device, wherein the content of ions other than platinum group element ions is 50 ppm or less based on the total weight of the encapsulating composition.

2. A sealing composition for an organic light-emitting device, wherein the reaction inhibitor according to claim 1 comprises at least one selected from among diallyl phthalate, diallyl maleate, diallyl oxalate, and tri-allyl isocyanurate.

3. In claim 1, the polyorganosiloxane is a sealing composition for an organic light-emitting device represented by the following chemical formula 1: [Chemical Formula 1] (R 1a R 2a R 3a SiO 1 / 2 ) aa (R 4a R 5a SiO 2 / 2 ) ba (R 6a SiO 3 / 2 ) ca (SiO 4 / 2 ) da In the above chemical formula 1, R 1a Inland R 6a are the same or different from each other, and each independently represents an alkyl group, an alkoxy group, an aryl group, a silanol group, or an alkenyl group, which are substituted or unsubstituted with halogen, R 1a , and R 4a Inland R 6a At least one of them is an alkenyl group, aa, ba, ca and da are the repetition numbers of each unit, and aa, ca and da are real numbers from 0 to 100, respectively, but aa+ca+da≥1. ba is a real number between 1 and 2,000, If each of aa, ba, ca, and da is 2 or more, the plural units are equal or different from each other.

4. In claim 1, the polyorganohydrogensiloxane is represented by the following chemical formula 2, a sealing composition for an organic light-emitting device: [Chemical Formula 2] (R 1b R 2b R 3b SiO 1 / 2 ) ab (R 4b R 5b SiO 2 / 2 ) bb (R 6b SiO 3 / 2 ) cb (SiO 4 / 2 ) db In the above chemical formula 2, R 1b Inland R 6b are the same or different from each other, and each independently represents an alkyl group, an alkoxy group, an aryl group or a silanol group, which are substituted or unsubstituted with halogen, R 1b , and R 4b Inland R 6b At least one of them is hydrogen, ab, bb, cb and db are the repetition numbers of each unit, and ab, cb and db are real numbers from 0 to 100, respectively, but ab+cb+db≥1. bb is a real number between 1 and 1,000, If each of ab, bb, cb and db is 2 or more, the multiple units are equal or different from each other.

5. A sealing composition for an organic light-emitting device, wherein the hydrosilylation catalyst according to claim 1 comprises at least one selected from the group consisting of ruthenium, rhodium, palladium, osmium, iridium, platinum, and complexes thereof.

6. A sealing composition according to claim 1, wherein the moisture content of the sealing composition is 400 ppm or less based on the total weight of the sealing composition.

7. In claim 1, the encapsulating composition is cured at 23°C to 100°C.

8. A sealant for an organic light-emitting device, which is a cured product of the sealant composition according to any one of claims 1 to 7.

9. An organic light-emitting device comprising the encapsulant of claim 8.

10. A step of applying a sealing composition according to any one of claims 1 to 7 on an organic light-emitting device; and A step of curing the applied sealing composition at 23°C to 100°C A method for encapsulating an organic light-emitting device including:

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