JP2015015250A - Resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermosetting type resin composition for sealing organic EL device which includes an epoxy resin, which can be caused to flow and cured rapidly even in a low-temperature region, and which enables the formation of a cured material layer having excellent moisture permeation resistance and high bonding strength.SOLUTION: A resin composition for sealing an organic EL device comprises: an epoxy resin; a hardening agent; and a particular moisture-absorptive metal oxide.

Description

  The present invention relates to a resin composition for sealing an organic EL element.

  Organic EL (Electroluminescence) elements are extremely sensitive to moisture, and when organic EL elements are used to construct displays and lighting devices, the organic materials themselves are altered by moisture, resulting in a decrease in luminance or even emission. There are drawbacks that the interface between the electrode and the organic EL layer is peeled off due to the influence of moisture, and the metal is oxidized to increase the resistance. Therefore, for example, as shown in FIG. 4, the glass plate 4 provided with the hygroscopic material 3 is opposed to the organic EL element 2 formed on the glass substrate 1 at a predetermined interval, so that the substrate 1 and the glass plate 4 are aligned. Can sealing is performed in which the gap is sealed in an inert gas atmosphere or in a vacuum state. However, since the thickness of the sealing structure portion including the organic EL element and the two glass plates is increased, the display and the lighting device cannot be sufficiently thinned.

  For this reason, as shown in FIG. 1, a curable resin composition layer 6 is formed on a glass substrate 1 having an organic EL element 2 formed on one side so as to cover the entire surface of the organic EL element 2, and from above A sealing structure in which the sealing substrate 7 is bonded and the curable resin composition layer 6 is cured to form a cured layer (hereinafter, this sealing structure is referred to as “entire surface sealing of an organic EL element” or simply “entire surface”). (Also referred to as “sealing”) has been proposed (Patent Document 1). However, since the curable resin composition described in Patent Document 1 is an acrylic ultraviolet curable resin composition, there is a problem of deterioration of the organic EL element due to ultraviolet rays and a place where ultraviolet rays do not reach (uncured portion). It occurs and there is a problem that it is difficult to obtain a highly reliable sealing structure. Moreover, compared with an epoxy resin, an acrylic resin is inferior in physical properties, such as heat resistance.

  Therefore, in recent years, application of a thermosetting resin composition mainly composed of an epoxy resin as a curable resin composition (sealing material) for sealing an entire surface of an organic EL element has been studied (for example, patents). Literature 2 etc.). However, the cured product layers obtained from the resin compositions described therein do not have sufficient moisture resistance, and it is difficult to say that the occurrence of defects due to moisture in the organic EL element can be sufficiently suppressed. In addition, since the organic EL element is not only susceptible to moisture but also susceptible to thermal degradation, in order to obtain a highly reliable sealing structure with a thermosetting resin composition mainly composed of an epoxy resin, the permeation resistance of the cured product is required. In addition to high wettability, it is necessary that the melt exhibits good fluidity and that curing proceeds rapidly in a low temperature range to form a cured layer with high adhesive strength. Satisfactory epoxy resin compositions have not been proposed.

JP-A-5-182759 JP 2006-70221 A

  An object of the present invention is to provide a resin composition for encapsulating an organic EL device, which has an appropriate melt viscosity and excellent low-temperature curability, and can form a cured product layer having high adhesion strength and excellent moisture resistance. Is to provide.

  As a result of intensive studies in order to solve the above problems, the present inventors have completed the present invention by using an epoxy resin composition containing a hygroscopic metal oxide having a specific average particle diameter.

That is, the present invention includes the following contents.
(1) An organic EL element sealing resin composition comprising an epoxy resin, a curing agent, and a hygroscopic metal oxide having an average particle diameter of 10 μm or less.
(2) The resin composition according to (1) above, wherein the hygroscopic metal oxide is a surface-treated hygroscopic metal oxide.
(3) The resin composition according to the above (1) or (2), wherein the curing agent is an ionic liquid.
(4) The resin composition as described in (3) above, wherein the ionic liquid comprises an ammonium cation or a phosphonium cation and an N-acylamino acid ion or a carboxylic acid anion.
(5) The resin composition according to any one of (1) to (4), further comprising an inorganic filler.
(6) A resin composition sheet for encapsulating an organic EL device, wherein the layer of the resin composition according to any one of (1) to (5) is formed on a support.
(7) An organic EL device comprising the resin composition sheet for sealing an organic EL element according to (6) above.

  According to the resin composition of the present invention, it is melted into a melt having an appropriate viscosity required for the laminating process of the entire sealing, and cured at a low temperature to form a cured product layer having high adhesion strength (adhesive strength). Therefore, the organic EL element is sealed without being left at a high temperature for a long time, and the cured product layer has high moisture permeability resistance. A reliable sealing structure can be formed.

FIG. 1 is a schematic cross-sectional view of a whole surface sealing structure of an organic EL element. FIG. 2 is a schematic view of a production process of a test piece used in the evaluation test of Examples and Comparative Examples. FIG. 3 is a schematic diagram of a sample (bonded product of two test pieces) subjected to a tensile test in an evaluation test of Examples and Comparative Examples. FIG. 4 is a schematic cross-sectional view of a can sealing structure of an organic EL element.

Hereinafter, the present invention will be described with reference to preferred embodiments thereof.
The resin composition for sealing an organic EL element of the present invention (hereinafter also simply referred to as “resin composition”) comprises an epoxy resin, a curing agent, and a hygroscopic metal oxide having an average particle size of 10 μm or less. It is characterized by containing.

[Epoxy resin]
The epoxy resin used in the present invention only needs to have an average of two or more epoxy groups per molecule. For example, bisphenol A type epoxy resin, biphenyl type epoxy resin, biphenyl aralkyl type epoxy resin, naphthol type epoxy resin, naphthalene type epoxy resin, bisphenol F type epoxy resin, phosphorus-containing epoxy resin, bisphenol S type epoxy resin, aromatic glycidylamine Type epoxy resin (for example, tetraglycidyl diaminodiphenylmethane, triglycidyl-p-aminophenol, diglycidyl toluidine, diglycidyl aniline, etc.), alicyclic epoxy resin, aliphatic chain epoxy resin, phenol novolac type epoxy resin, cresol novolac Type epoxy resin, bisphenol A novolac type epoxy resin, epoxy resin having butadiene structure, diglycidyl etherified product of bisphenol, naphthalenediol Diglycidyl ethers of Le, glycidyl ethers of phenols, and diglycidyl ethers of alcohols, and alkyl substituted derivatives of these epoxy resins, halides and hydrogenated products or the like. Any one of these epoxy resins can be used or a mixture of two or more can be used.

  Among these, the epoxy resin is a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a phenol novolac type epoxy resin, a biphenyl aralkyl type from the viewpoint of maintaining the high heat resistance and low moisture permeability of the resin composition of the present invention. Epoxy resins, phenol aralkyl type epoxy resins, aromatic glycidyl amine type epoxy resins, epoxy resins having a dicyclopentadiene structure, and the like are preferable. Two or more epoxy resins may be mixed and used.

  The epoxy resin may be liquid, solid, or both liquid and solid. Here, “liquid” and “solid” are states of the epoxy resin at normal temperature (25 ° C.). From the viewpoint of coatability, workability, and adhesiveness, it is preferable that at least 10% by weight or more of the entire epoxy resin to be used is liquid.

  In the present invention, the epoxy resin preferably has an epoxy equivalent in the range of 100 to 1000, more preferably in the range of 120 to 1000, from the viewpoint of reactivity. Here, the epoxy equivalent is the number of grams (g / eq) of a resin containing 1 gram equivalent of an epoxy group, and is measured according to the method defined in JIS K 7236.

[Curing agent]
Although it will not specifically limit as a hardening | curing agent used for the resin composition of this invention if it has a function which hardens | cures an epoxy resin, The viewpoint which suppresses the thermal deterioration of the organic EL element at the time of the hardening process of a resin composition. Therefore, those capable of curing the epoxy resin at a temperature of 140 ° C. or lower (preferably 120 ° C. or lower) are preferable.

  Examples include primary amines, secondary amines, tertiary amine type curing agents, polyaminoamide type curing agents, dicyandiamide, organic acid dihydrazide, etc. Among them, amine adduct type compounds (Amure PN- 23, Amicure MY-24, Amicure PN-D, Amicure MY-D, Amicure PN-H, Amicure MY-H, Amicure PN-31, Amicure PN-40, Amicure PN-40J, etc. (all of which are Ajinomoto Fine Techno Co., Ltd.) )), Organic acid dihydrazide (Amicure VDH-J, Amicure UDH, Amicure LDH, etc. (all manufactured by Ajinomoto Fine Techno Co., Ltd.)) and the like are particularly preferable.

  An ionic liquid that can cure the epoxy resin at a temperature of 140 ° C. or lower (preferably 120 ° C. or lower), that is, a salt that can melt in a temperature range of 140 ° C. or lower (preferably 120 ° C. or lower), A salt having a curing action of the resin can also be particularly preferably used. In the resin composition of the present invention, it is desirable to use the ionic liquid in a state in which the ionic liquid is uniformly dissolved in the epoxy resin, and the ionic liquid advantageously works to improve the moisture resistance of the cured resin.

  Examples of cations constituting such an ionic liquid include imidazolium ions, piperidinium ions, pyrrolidinium ions, pyrazonium ions, guanidinium ions, pyridinium ions, and other ammonium cations; tetraalkylphosphonium cations (for example, tetrabutylphosphonium ions, Phosphonium cations such as tributylhexyl phosphonium ion; and sulfonium cations such as triethylsulfonium ion.

  Examples of the anion constituting the ionic liquid include halide anions such as fluoride ion, chloride ion, bromide ion and iodide ion; alkyl sulfate anions such as methanesulfonate ion; trifluoromethanesulfonate ion, Fluorine-containing compound anions such as hexafluorophosphonate ion, trifluorotris (pentafluoroethyl) phosphonate ion, bis (trifluoromethanesulfonyl) imide ion, trifluoroacetate ion, tetrafluoroborate ion; phenol ion, 2-methoxy Phenolic anions such as phenol ion and 2,6-di-tert-butylphenol ion; acidic amino acid ions such as aspartate ion and glutamate ion; glycine ion, alanine ion and phenyl Neutral amino acid ion such as lanine ion; N-acyl amino acid ion represented by the following general formula (1) such as N-benzoylalanine ion, N-acetylphenylalanine ion, N-acetylglycine ion; formate ion, acetate ion, decanoic acid Carboxylic acid anions such as ions, 2-pyrrolidone-5-carboxylic acid ions, α-lipoic acid ions, lactic acid ions, tartrate ions, hippuric acid ions, N-methyl hippuric acid ions, benzoic acid ions, and the like.

(However, R—CO— is an acyl group derived from a linear or branched fatty acid having 1 to 5 carbon atoms, or a substituted or unsubstituted benzoyl group, —NH—CHX—CO ₂ is aspartic acid, Acidic amino acid ions such as glutamic acid or neutral amino acid ions such as glycine, alanine and phenylalanine.)

  Among the above, the cation is preferably an ammonium cation or a phosphonium cation, and more preferably an imidazolium ion or a phosphonium ion. More specifically, the imidazolium ion is 1-ethyl-3-methylimidazolium ion, 1-butyl-3-methylimidazolium ion, 1-propyl-3-methylimidazolium ion, or the like.

  The anion is preferably a phenolic anion, an N-acylamino acid ion or a carboxylic acid anion represented by the general formula (1), and more preferably an N-acylamino acid ion or a carboxylic acid anion.

  Specific examples of the phenolic anion include 2,6-di-tert-butylphenol ion. Specific examples of the carboxylic acid anion include acetate ion, decanoate ion, 2-pyrrolidone-5-carboxylate ion, formate ion, α-lipoic acid ion, lactate ion, tartrate ion, hippurate ion, N- Methyl hippurate ion, and the like. Among them, acetate ion, 2-pyrrolidone-5-carboxylate ion, formate ion, lactate ion, tartrate ion, hippurate ion, and N-methylhippurate ion are preferable, acetate ion, N -Methyl hippurate ion and formate ion are particularly preferred. Specific examples of the N-acylamino acid ion represented by the general formula (1) include N-benzoylalanine ion, N-acetylphenylalanine ion, aspartate ion, glycine ion, N-acetylglycine ion, and the like. Among these, N-benzoylalanine ion, N-acetylphenylalanine ion, and N-acetylglycine ion are preferable, and N-acetylglycine ion is particularly preferable.

  Specific ionic liquids include, for example, 1-butyl-3-methylimidazolium lactate, tetrabutylphosphonium-2-pyrrolidone-5-carboxylate, tetrabutylphosphonium acetate, tetrabutylphosphonium decanoate, tetrabutylphosphonium tri Fluoroacetate, tetrabutylphosphonium α-lipoate, tetrabutylphosphonium formate, tetrabutylphosphonium lactate, bis (tetrabutylphosphonium) tartrate, tetrabutylphosphonium hippurate, tetrabutylphosphonium N-methylhippurate, benzoyl-DL -Alanine tetrabutylphosphonium salt, N-acetylphenylalanine tetrabutylphosphonium salt, 2,6-di-tert-butylphenoltetrabutylphosphonium Salt, L-aspartic acid monotetrabutylphosphonium salt, glycine tetrabutylphosphonium salt, N-acetylglycine tetrabutylphosphonium salt, 1-ethyl-3-methylimidazolium lactate, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium formate, 1-ethyl-3-methylimidazolium hippurate, 1-ethyl-3-methylimidazolium N-methylhippurate, bis (1-ethyl-3-tartrate) Methyl imidazolium) salt and N-acetylglycine 1-ethyl-3-methylimidazolium salt are preferred, N-acetylglycine tetrabutylphosphonium salt, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-formate Methylimidazolium salt, 1-ethyl-3 hippurate -Methylimidazolium salt, N-methylhippuric acid 1-ethyl-3-methylimidazolium salt is particularly preferred.

As a method for synthesizing the ionic liquid, a precursor composed of a cation moiety such as an alkylimidazolium, alkylpyridinium, alkylammonium and alkylsulfonium ions and an anion moiety containing a halogen is added to NaBF ₄ , NaPF ₆ , CF ₃ SO ₃ Anion exchange method in which Na, LiN (SO ₂ CF ₃ ) ₂ or the like is reacted, an acid ester in which an organic acid residue becomes a counter anion while introducing an alkyl group by reacting an amine substance with an acid ester Methods, and neutralization methods in which amines are neutralized with an organic acid to obtain a salt, but are not limited thereto. In the neutralization method using an anion, a cation, and a solvent, it is possible to use an anion and a cation in equal amounts, distill off the solvent in the obtained reaction solution, and use it as it is. Furthermore, an organic solvent (methanol, (Toluene, ethyl acetate, acetone, etc.) may be added and concentrated.

  In the resin composition of the present invention, the content of the curing agent is preferably used in the range of 0.1 to 50% by weight with respect to the total amount (nonvolatile content) of the epoxy resin contained in the resin composition. If the amount is less than this range, sufficient curability may not be obtained. If the amount is more than 50% by weight, the storage stability of the resin composition may be impaired. In addition, when using an ionic liquid, 0.1-10 weight% is preferable with respect to the total amount (nonvolatile content) of an epoxy resin from points, such as the moisture permeability of the hardened | cured material of a resin composition.

[Hygroscopic metal oxides]
The resin composition of the present invention contains a hygroscopic metal oxide. Here, the “hygroscopic metal oxide” means a metal oxide that has a capability of absorbing moisture and chemically reacts with moisture that has been absorbed to become a hydroxide. Specific examples include calcium oxide, magnesium oxide, strontium oxide, barium oxide, and the like, among which calcium oxide is preferable. Such a hygroscopic metal oxide is known as a hygroscopic material in various fields, but in the present invention, a hygroscopic metal oxide having an average particle size of 10 μm or less (preferably 5 μm or less) is used. By using such a microscopic hygroscopic metal oxide, not only a high moisture permeation resistance is imparted to the cured layer obtained by curing the resin composition of the present invention, but also the adhesion of the cured layer is improved. Can be increased.

  Note that if the average particle size of the hygroscopic metal oxide is too small, the particles tend to agglomerate with each other. Therefore, a sufficiently high moisture permeability and good adhesion are imparted to the cured product due to poor dispersion in the composition. It can be difficult to do. Therefore, the hygroscopic metal oxide preferably has an average particle size of 0.001 μm or more, more preferably 0.01 μm or more.

  Further, it is particularly preferable that the hygroscopic metal oxide has an average particle diameter in the above-mentioned preferable range and does not contain coarse particles having a particle diameter of 20 μm or more. By not including such coarse particles, it is advantageous in that the EL element is hardly damaged in the sealing process.

  The average particle diameter of the hygroscopic metal oxide can be measured by a laser diffraction / scattering method based on the Mie scattering theory. Specifically, the particle size distribution of the inorganic filler can be created on a volume basis by a laser diffraction particle size distribution measuring device, and the median diameter can be measured as the average particle diameter. As the measurement sample, a hygroscopic metal oxide dispersed in water by ultrasonic waves can be preferably used. As a laser diffraction type particle size distribution measuring apparatus, LA-500 manufactured by Horiba, Ltd. can be used.

  As the hygroscopic metal oxide, a surface treated with a surface treatment agent can be used. By using such a surface-treated hygroscopic metal oxide, the storage stability of the resin composition can be further increased, and the moisture in the resin reacts with the hygroscopic metal oxide before curing. And thickening of the composition over time can be prevented.

  As the surface treatment agent used for the surface treatment, for example, higher fatty acids, alkylsilanes, silane coupling agents and the like can be used, and among these, higher fatty acids or alkylsilanes are preferable.

  The higher fatty acid is preferably a higher fatty acid having 18 or more carbon atoms such as stearic acid, montanic acid, myristic acid and palmitic acid. These can be used by selecting one or more. Of these, stearic acid is preferred.

  Alkylsilanes include methyltrimethoxysilane, ethyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, octadecyltrimethoxysilane, dimethyldimethoxysilane, octyltriethoxysilane, n-octadecyldimethyl ( 3- (trimethoxysilyl) propyl) ammonium chloride and the like can be mentioned, and these can be used alone or in combination of two or more.

  Examples of the silane coupling agent include 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropyl (dimethoxy) methylsilane, and 2- (3,4-epoxycyclohexyl) ethyltrimethoxy. Epoxy silane coupling agents such as silane; mercapto silane coupling agents such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane and 11-mercaptoundecyltrimethoxysilane 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldimethoxymethylsilane, N-phenyl-3-aminopropyltrime Amino silane cups such as xylsilane, N-methylaminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane and N- (2-aminoethyl) -3-aminopropyldimethoxymethylsilane Ring agent; Ureido silane coupling agent such as 3-ureidopropyltriethoxysilane, vinyl silane coupling agent such as vinyltrimethoxysilane, vinyltriethoxysilane and vinylmethyldiethoxysilane; p-styryltrimethoxysilane Styryl-based silane coupling agents; acrylate-based silane coupling agents such as 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltrimethoxysilane; 3-isocyanatopropyltrimethoxy Isocyanate-based silane coupling agents such as silane, sulfide-based silane coupling agents such as bis (triethoxysilylpropyl) disulfide and bis (triethoxysilylpropyl) tetrasulfide; phenyltrimethoxysilane, methacryloxypropyltrimethoxysilane, imidazole Examples thereof include silane and triazine silane. These can be used by selecting one or more.

  For example, the surface treatment may be performed by adding and spraying a surface treatment agent (higher fatty acid, alkylsilane, or silane coupling agent) while stirring and dispersing untreated hygroscopic metal oxide at room temperature using a mixer. This can be done by stirring for a minute. As a mixer, a well-known mixer can be used, For example, blenders, such as V blender, a ribbon blender, and a bubble cone blender, mixers, such as a Henschel mixer and a concrete mixer, a ball mill, a cutter mill, etc. are mentioned. Further, when the hygroscopic material is pulverized with a ball mill or the like, a method of surface treatment by mixing the higher fatty acid, alkylsilanes or silane coupling agent is also possible. The treatment amount of the surface treatment agent (higher fatty acid, alkylsilanes or silane coupling agent) varies depending on the type of the hygroscopic metal oxide or the type of the surface treatment agent, but 1 to 10 with respect to the hygroscopic metal oxide. % By weight is preferred, and 1 to 5% by weight is more preferred.

  In the resin composition of the present invention, the content of the hygroscopic metal oxide is preferably in the range of 1 to 40% by weight, more preferably in the range of 1 to 30% by weight with respect to 100% by weight of the nonvolatile content in the resin composition. The range of 5 to 20% by weight is more preferable, 7 to 18% by weight is still more preferable, and 9 to 16% by weight is even more preferable. If the content is too small, the effect of blending the hygroscopic metal oxide is not sufficiently obtained. If the content is too large, the viscosity of the composition tends to increase and the strength of the cured product decreases. It tends to be brittle.

[Inorganic filler]
The resin composition of the present invention can contain an inorganic filler from the viewpoints of moisture permeability of the cured product and prevention of repelling during film processing. Examples of the inorganic filler include silica, alumina, barium sulfate, talc, clay, mica, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, boron nitride, aluminum borate, barium titanate, strontium titanate, Examples include calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, and calcium zirconate. Among these, talc and mica are preferable, and talc is particularly preferable from the viewpoint of maintaining low moisture permeability and high adhesion of the cured resin. The inorganic filler may be used alone or in combination of two or more.

  In the resin composition of the present invention, when an inorganic filler is used, the content of the inorganic filler is preferably in the range of 1 to 50% by weight with respect to 100% by weight of the nonvolatile content in the resin composition. The range is preferably 1 to 40% by weight, more preferably 5 to 30% by weight, and still more preferably 10 to 20% by weight. If the content is too small, the effect of blending the inorganic filler and the adhesion to the substrate tend not to be sufficiently obtained. If the content is too large, the viscosity of the composition tends to increase and curing The strength of the object tends to decrease and become brittle.

  The upper limit of the average particle size of the inorganic filler used in the present invention is preferably 10 μm or less, more preferably 5 μm, even more preferably 2.5 μm, and even more preferably 1.5 μm from the viewpoint of handleability. On the other hand, the lower limit value of the average particle diameter of the inorganic filler is preferably 0.5 μm from the viewpoint of preventing the viscosity of the resin from increasing.

  The average particle diameter of the inorganic filler can be measured by a laser diffraction / scattering method based on Mie scattering theory. Specifically, the particle size distribution of the inorganic filler can be created on a volume basis by a laser diffraction particle size distribution measuring device, and the median diameter can be measured as the average particle diameter. As the measurement sample, an inorganic filler dispersed in water by ultrasonic waves can be preferably used. As a laser diffraction type particle size distribution measuring apparatus, LA-500 manufactured by Horiba, Ltd. can be used.

[Rubber particles]
The resin composition of the present invention may contain rubber particles for the purpose of improving the mechanical strength of the cured product and relaxing the stress. The rubber particles are not dissolved in an organic solvent when preparing the resin composition, are not compatible with components in the resin composition such as an epoxy resin, and exist in a dispersed state in the varnish of the resin composition Is preferred. Such rubber particles can generally be prepared by increasing the molecular weight of the rubber component to a level that does not dissolve in an organic solvent or resin and making it into particles. Specifically, core-shell type rubber particles, Examples thereof include acrylonitrile butadiene rubber particles, crosslinked styrene butadiene rubber particles, and acrylic rubber particles. The core-shell type rubber particles are rubber particles having a core layer and a shell layer. For example, the outer shell layer is a glassy polymer and the inner core layer is a rubbery polymer. Examples include a three-layer structure in which the shell layer is a glassy polymer, the intermediate layer is a rubbery polymer, and the core layer is a glassy polymer. The glass layer is made of, for example, a polymer of methyl methacrylate, and the rubbery polymer layer is made of, for example, a butyl acrylate polymer (butyl rubber). Specific examples of the core-shell type rubber particles include Staphyloid AC3832, AC3816N (manufactured by Ganz Kasei Co., Ltd.), Metabrene KW-4426 (manufactured by Mitsubishi Rayon Co., Ltd.), F351 (manufactured by Nippon Zeon Co., Ltd.), and the like. Can be mentioned. Specific examples of acrylonitrile butadiene rubber (NBR) particles include XER-91 (manufactured by JSR Corporation). Specific examples of styrene butadiene rubber (SBR) particles include XSK-500 (manufactured by JSR Corporation). Specific examples of the acrylic rubber particles include Methbrene W300A and W450A (manufactured by Mitsubishi Rayon Co., Ltd.).

  The average particle diameter of the rubber particles is preferably in the range of 0.005 to 1 μm, and more preferably in the range of 0.2 to 0.6 μm. The average particle diameter of such rubber particles can be measured using a dynamic light scattering method. For example, rubber particles are uniformly dispersed in an appropriate organic solvent by ultrasonic waves, etc., and using FPRA-1000 (manufactured by Otsuka Electronics Co., Ltd.), the particle size distribution of the rubber particles is created on a weight basis, and the median diameter is determined. The average particle diameter is measured.

  In the resin composition of the present invention, when rubber particles are used, the content of the rubber particles is preferably 0.1 to 20% by weight with respect to 100% by weight of the nonvolatile content in the resin composition, and 0.1 to 10%. Weight percent is more preferred. If the amount is less than 0.1% by weight, the effect of blending the rubber particles cannot be sufficiently obtained. If the amount is more than 20% by weight, the heat resistance and moisture permeability may be lowered.

[Thermoplastic resin]
The resin composition of the present invention can contain a thermoplastic resin from the viewpoints of imparting flexibility to the cured product and maintaining good processability when coating the resin composition. Examples of the thermoplastic resin include phenoxy resin, polyvinyl acetal resin, polyimide resin, polyamideimide resin, polyethersulfone resin, and polysulfone resin. Any one of these thermoplastic resins may be used, or two or more thereof may be mixed and used. The thermoplastic resin preferably has a weight average molecular weight of 30,000 or more, more preferably 50,000 or more, from the viewpoint of imparting flexibility and preventing repelling during coating. However, if the weight average molecular weight is too large, the compatibility with the epoxy resin tends to be reduced. Therefore, the weight average molecular weight is preferably 1,000,000 or less, more preferably 800,000 or less. .

  In addition, "the weight average molecular weight of a thermoplastic resin" here is measured by the gel permeation chromatography (GPC) method (polystyrene conversion). Specifically, the weight average molecular weight by the GPC method is LC-9A / RID-6A manufactured by Shimadzu Corporation as a measuring device, and Shodex K-800P / K-804L / K- manufactured by Showa Denko KK as a column. 804 L can be measured at a column temperature of 40 ° C. using chloroform or the like as a mobile phase, and can be calculated using a standard polystyrene calibration curve.

  Of the above-mentioned examples, the phenoxy resin is particularly preferable as the thermoplastic resin. The phenoxy resin is preferable because it has good compatibility with the “epoxy resin” and has little influence on the adhesiveness and moisture permeability resistance of the cured product of the resin composition of the present invention.

  Examples of the phenoxy resin include bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenol acetophenone skeleton, novolac skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, terpene skeleton, Examples thereof include those having one or more skeletons selected from a trimethylcyclohexane skeleton. Two or more phenoxy resins may be mixed and used.

  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 Epoxy Resin ( YX6954 (bisphenol acetophenone skeleton-containing phenoxy resin), Union Carbide PKHH (weight average molecular weight (Mw) 42600, number average molecular weight (Mn) 11200) and the like are suitable, and FX280, FX293 manufactured by Toto Kasei Co., Ltd. YL7553BH30, YL6794, YL7213, YL7290, YL7482 etc. manufactured by Japan Epoxy Resins Co., Ltd. can also be mentioned.

  In the resin composition of the present invention, when a thermoplastic resin is used, the content of the thermoplastic resin is preferably 1 to 50% by weight, preferably 3 to 25% by weight with respect to 100% by weight of the nonvolatile content in the resin composition. Is more preferable. If the amount is less than 1% by weight, the effect of blending the thermoplastic resin cannot be sufficiently obtained. If the amount is more than 50% by weight, the moisture permeability of the cured product tends to be lowered.

[Coupling agent]
The resin composition of the present invention can contain a coupling agent from the viewpoints of adhesion to the adherend, moisture permeability of the cured product, and the like. Examples of such coupling agents include titanium coupling agents, aluminum coupling agents, silane coupling agents, and the like. Among these, a silane coupling agent is preferable. Moreover, a coupling agent can be used 1 type or in combination of 2 or more types.

  Examples of the silane coupling agent include 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropyl (dimethoxy) methylsilane, and 2- (3,4-epoxycyclohexyl) ethyltrimethoxy. Epoxy silane coupling agents such as silane; mercapto silane coupling agents such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane and 11-mercaptoundecyltrimethoxysilane 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldimethoxymethylsilane, N-phenyl-3-aminopropyltrime Amino silane cups such as xylsilane, N-methylaminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane and N- (2-aminoethyl) -3-aminopropyldimethoxymethylsilane Ring agent; Ureido silane coupling agent such as 3-ureidopropyltriethoxysilane, vinyl silane coupling agent such as vinyltrimethoxysilane, vinyltriethoxysilane and vinylmethyldiethoxysilane; p-styryltrimethoxysilane Styryl-based silane coupling agents; acrylate-based silane coupling agents such as 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltrimethoxysilane; 3-isocyanatopropyltrimethoxy Isocyanate-based silane coupling agents such as silane, sulfide-based silane coupling agents such as bis (triethoxysilylpropyl) disulfide and bis (triethoxysilylpropyl) tetrasulfide; phenyltrimethoxysilane, methacryloxypropyltrimethoxysilane, imidazole Examples thereof include silane and triazine silane. Among these, an epoxy-based silane coupling agent is particularly suitable.

  In the resin composition of the present invention, when a coupling agent is used, the content of the coupling agent is preferably 0.5 to 10% by weight with respect to 100% by weight of the nonvolatile content in the resin composition. More preferred is ˜5% by weight. When it contains outside this range, the adhesive improvement effect by coupling agent addition cannot be acquired.

  The resin composition of the present invention may optionally contain various resin additives other than the components described above as long as the effects of the present invention are exhibited. Examples of such resin additives include organic fillers such as silicon powder, nylon powder, and fluorine powder, thickeners such as olben and benton, silicone-based, fluorine-based, and polymer-based antifoaming agents or leveling agents. , Adhesion-imparting agents such as triazole compounds, thiazole compounds, triazine compounds, porphyrin compounds, etc.

[Resin composition sheet for sealing organic EL elements]
The resin composition of the present invention is directly applied to a substrate on which an organic EL element is formed (hereinafter also abbreviated as “organic EL element forming substrate”) to form a resin composition layer that covers the organic EL element. An organic EL element sealing resin composition sheet in which a layer of the resin composition of the present invention is formed on a support is prepared, and the organic EL element sealing resin composition sheet is used as an organic EL element forming substrate. The organic EL element may be covered with the resin composition layer by laminating and transferring the resin composition layer onto the organic EL element forming substrate. Industrially, a method using such a resin composition sheet for sealing an organic EL element is suitable.

  The organic EL element sealing resin composition sheet is prepared by a method known to those skilled in the art, for example, by preparing a varnish in which the resin composition is dissolved in an organic solvent, applying the varnish on the support, and further heating or hot air. The organic solvent can be dried by spraying or the like to form a resin composition layer.

  Examples of the organic solvent include ketones such as acetone, methyl ethyl ketone (hereinafter abbreviated as “MEK”), cyclohexanone, and acetates such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate. Carbitols such as cellosolve and butyl carbitol, aromatic hydrocarbons such as toluene and xylene, dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like. One of these organic solvents may be used alone, or two or more thereof may be used in combination.

  There are no particular restrictions on the drying conditions, but 3 to 15 minutes at 50 to 100 ° C. are preferred.

  The thickness of the resin composition layer formed after drying is preferably 3 μm to 200 μm, more preferably 5 μm to 100 μm, and still more preferably 5 μm to 50 μm.

  As will be described later, in the sealing structure in which the sealing substrate is laminated on the resin composition layer (cured layer) (see FIG. 1), the intrusion of moisture is only from the side of the resin composition layer. It is desirable to reduce the thickness of the resin composition layer in order to reduce the contact area with the outside air and to block moisture. On the other hand, when the layer thickness is too small, the uniformity of the thickness of the coating film is lowered after transfer onto the organic EL element forming substrate, or the workability when the sealing substrate is bonded is liable to be lowered.

The resin composition layer may be protected with a protective film. By protecting the resin composition layer with the protective film, it is possible to prevent adhesion or scratches of dust or the like to the surface of the resin composition layer.
As the support used for the resin composition sheet for sealing an organic EL element, it is preferable to use a support having moisture resistance, and the support having moisture resistance is used as it is as a sealing substrate. Examples of such a moisture-proof support (= sealing substrate) include a moisture-proof plastic film, or a metal foil such as a copper foil or an aluminum foil. Examples of the moisture-proof plastic film include a plastic film in which an inorganic substance such as silicon oxide (silica), silicon nitride, SiCN, or amorphous silicon is deposited on the surface. Here, the “plastic film” is, for example, a polyolefin such as polyethylene, polypropylene, or polyvinyl chloride, a polyethylene terephthalate (hereinafter sometimes abbreviated as “PET”), a polyester such as polyethylene naphthalate, a polycarbonate, a polyimide, or the like. A plastic film can be used, and among them, PET is preferable. Examples of commercially available moisture-proof plastic films include Tech Barrier HX, AX, LX, L series (Mitsubishi Resin Co., Ltd.) and X-BARRIER (Mitsubishi Resin Co., Ltd.) with a further improved moisture-proof effect. It is done. A sealing substrate having a multilayer structure of two or more layers may be used.

  Note that a plastic film having no moisture resistance (for example, a plastic film on which the above-described inorganic material is not deposited) can be used as a support. In that case, an organic EL element is formed on the substrate on which the organic EL element is formed. After forming the resin composition layer with the EL element sealing resin composition sheet, it is preferable to peel the support, and then separately laminate a sealing substrate on the resin composition layer.

  As the protective film in the resin composition sheet for sealing an organic EL element, the plastic film exemplified above can be used. The support and the protective film may be subjected to a release treatment in addition to the mat treatment and the corona treatment. Examples of the release treatment include a release treatment with a release agent such as a silicone resin release agent, an alkyd resin release agent, and a fluororesin release agent.

  Although the thickness of a support body is not specifically limited, From viewpoints, such as the handleability of the resin composition sheet for organic electroluminescent element sealing, the range of 10-150 micrometers is preferable, More preferably, it is used in the range of 20-100 micrometers. The thickness of the protective film is not particularly limited, but is preferably in the range of 1 to 40 μm, and more preferably in the range of 10 to 30 μm.

[Sealing of organic EL elements]
The sealing of the organic EL element using the resin composition for sealing an organic EL element or the resin composition sheet for sealing an organic EL element of the present invention can be performed, for example, as follows. First, a resin composition layer is formed so as to cover the organic EL element on the organic EL element forming substrate.

  When the resin composition is used directly, it is applied to form a resin composition layer. The resin composition is preferably used in a varnish state in which an epoxy resin, an ionic liquid, and other materials blended as necessary are mixed. The above-described solvents and the like may be added as necessary to the extent that they do not affect the organic EL element. When a solvent is used, drying is performed after coating to form a resin composition layer. The thickness of the resin composition layer is the same as the thickness of the resin composition layer in the above-mentioned organic EL element sealing resin composition sheet.

  When using the resin composition sheet for sealing an organic EL element, if the resin composition layer of the resin composition sheet for sealing an organic EL element is protected with a protective film, the resin composition sheet is peeled off and then the resin composition The organic EL element sealing resin composition sheet is laminated to the organic EL element forming substrate so that the layer is in direct contact with the organic EL element forming substrate. The laminating method may be a batch method or a continuous method using a roll. In addition, when a sealing base material is used as the support for the resin composition sheet for sealing an organic EL element, the support is used after laminating the resin composition sheet for sealing an organic EL element on the organic EL element forming substrate. Without being peeled off, the thermosetting operation of the resin composition layer described later can be performed as it is (this completes the sealing of the organic EL element). A preferable sealing structure as shown in FIG. 1 can be formed after thermosetting the resin composition layer.

On the other hand, when a support that does not have moisture resistance is used, the support is peeled off, the sealing substrate is pressure-bonded to the exposed resin composition layer, and a thermosetting operation of the resin composition layer described below is performed. preferable. In this case, as the sealing substrate, in addition to the above-mentioned moisture-proof plastic film, copper foil, aluminum foil or other metal foil, a glass plate or metal plate that is unsuitable for use as a support for a resin composition sheet The base material which does not have flexibility, such as, can also be used. The pressure at the time of press-bonding the sealing substrate is preferably about 0.5 to ¹⁰ kgf / cm ² , and the temperature is about 50 to 130 ° C. when the pressure is applied under heating. The thickness of the sealing substrate is preferably 5 mm or less from the viewpoint of making the organic EL device itself thin and light, more preferably 1 mm or less, particularly preferably 100 μm or less, and 5 μm or more from the viewpoint of preventing moisture permeation. More preferably, it is 10 μm or more, and particularly preferably 20 μm or more. Two or more sealing substrates may be bonded together.

  As shown in FIG. 1, when the organic EL element 2 is formed on the glass substrate 1, the sealing substrate 7 is not necessarily transparent if the glass substrate 1 side is used as a display surface of a display or a light emitting surface of a lighting fixture. It is not necessary to use a material, and a metal plate, a metal foil, an opaque plastic film (or plate), or the like can be used. On the contrary, when the organic EL element is formed on a substrate made of an opaque or low-transparency material, since the sealing substrate side needs to be the display surface of the display or the light emitting surface of the lighting fixture, As the sealing substrate, a glass plate, a transparent plastic film (or plate), or the like is used.

  There is no restriction | limiting in particular in the method of thermosetting a resin composition layer, A various thing can be used. For example, a hot air circulation oven, an infrared heater, a heat gun, a high frequency induction heating device, heating by pressure bonding of a heat tool, and the like can be mentioned. The resin composition of the present invention has extremely good low-temperature curability, and is generally not more than 120 minutes, preferably in a low temperature range of 140 ° C. or less, preferably 120 ° C. or less, more preferably 110 ° C. or less. It can be cured in a short time of 90 minutes or less, more preferably 60 minutes or less. Therefore, the deterioration of the organic EL element due to heat can be extremely reduced. The lower limit of each of the curing temperature and the curing time is preferably 50 ° C. or higher, more preferably 55 ° C. or higher, from the viewpoint of ensuring sufficiently satisfactory adhesiveness (adhesiveness) of the cured product. The curing time is preferably 20 minutes or longer, and more preferably 30 minutes or longer.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited at all by the following examples.

The materials (raw materials) used in Examples and Comparative Examples are as follows.
(A) Epoxy resin 828EL (manufactured by Japan Epoxy Resin Co., Ltd.): Liquid bisphenol A type epoxy resin, epoxy equivalent (185 g / eq), low chlorine type epoxy resin.
NC3000 (manufactured by Nippon Kayaku Co., Ltd.): Biphenylaralkyl type epoxy resin, epoxy equivalent (275 g / eq), prepared in MEK solution with 70 wt% solid content.
GOT (manufactured by Nippon Kayaku Co., Ltd.): orthotoluidine diglycidylamine, epoxy equivalent (135 g / eq).
Epicron EXA-835LV (manufactured by DIC): Bisphenol A type and F type mixed epoxy resin low chlorine type, epoxy equivalent (165 g / eq).
Epicoat 828 (manufactured by Japan Epoxy Resin): Bisphenol A type epoxy resin low chlorine type.
Epicote 1001 (manufactured by Japan Epoxy Resin Co.): Bisphenol A type epoxy resin.
・ Rubber fine particle-dispersed liquid epoxy resin (“BPA328” manufactured by Nippon Shokubai Co., Ltd.): A composition comprising 17% by weight of bisphenol A type epoxy resin having an epoxy equivalent of 185 and two-layer acrylic resin particles having a primary particle size of 0.3 μm Epoxy equivalent 230g / eq))
Solid epoxy resin (“HP7200H” manufactured by DIC: dicyclopentadiene type solid epoxy resin, epoxy equivalent (278 g / eq))

(B) Curing agent (ionic liquid)
・ N-acetylglycine tetrabutylphosphonium salt (solid dispersion type curing agent)
・ Amicure PN40-J (Ajinomoto Fine Techno Co., Ltd., average particle size 2.5 μm)
・ VDH-J (manufactured by Ajinomoto Fine Techno Co.) ・ Amicure MY-24 (manufactured by Ajinomoto Fine Techno Co., average particle size 10 μm)
2PZ-CNS-PW (manufactured by Shikoku Kasei Co., Ltd.): ground product of 1-cyanoethyl-2-phenylimidazolium trimellitate, average particle size 10 μm
U-CAT3502T (manufactured by San Apro): latent curing agent (acid anhydride type curing agent)
・ Licacid MH-700 (manufactured by Nippon Nippon Chemical Co., Ltd.): Methylhexahydrophthalic anhydride (liquid curing agent)
2E4MZ (manufactured by Shikoku Chemicals): 2-ethyl-4-methylimidazole 1B2MZ (manufactured by Shikoku Chemicals): 1-benzyl-2-methylimidazole

(C) Phenoxy resin YX6954 (manufactured by Japan Epoxy Resin Co., Ltd.): A heat-resistant phenoxy resin, a weight average molecular weight (40,000), and a 35 wt% solid MEK solution.
YL7213 (manufactured by Japan Epoxy Resin Co., Ltd.): A high heat-resistant phenoxy resin, a weight average molecular weight (35,000), and a 35 wt% solid MEK solution prepared for use.
PKHH (manufactured by InChem): A heat-resistant phenoxy resin, a weight average molecular weight (42,600), and a 20 wt% solid MEK solution prepared for use.

(D) Rubber particles F351 (manufactured by Zeon Corporation): acrylic core-shell resin particles, average particle size (0.3 μm).

(E) Hygroscopic metal oxide Moistop # 10 (manufactured by Sankyo Flour Mills): calcium oxide, average particle size (4 μm), maximum particle size (15 μm).
Firing dolomite: MEK slurry (40 wt% as solid content, average particle size: 0.87 μm) of wet pulverized “light calcined dolomite” manufactured by Yoshizawa Lime Company.

(F) Inorganic filler SG95S (manufactured by Nippon Talc): Talc, average particle size (1.4 μm).
D-600 (manufactured by Nippon Talc Co., Ltd.): MEK slurry (30 wt% as solid content) of wet pulverized, average particle size (0.72 μm).

(G) Surface treatment agent KBM3103 (manufactured by Shin-Etsu Silicone): Decyltrimethoxysilane Stearic acid

(H) Coupling agent KBM-403 (manufactured by Shin-Etsu Silicone): 3-glycidoxypropyltrimethoxysilane

  Each composition of an Example and a comparative example was adjusted with the procedure shown next. The blending was carried out in the amounts by weight shown in Tables 1 and 2.

Example 1
Liquid bisphenol A type epoxy resin (“828EL” manufactured by Japan Epoxy Resin Co., Ltd.) and orthotoluidine diglycidylamine (“GOT” manufactured by Nippon Kayaku Co., Ltd.), acrylic core shell resin (“F351” manufactured by Nippon Zeon Co., Ltd.), A solid dispersion type curing agent (“VDH-J” manufactured by Ajinomoto Fine Techno Co., Ltd., “PN40-J” manufactured by Ajinomoto Fine Techno Co., Ltd.) and a surface treatment agent (“KBM-” manufactured by Shin-Etsu Silicone Co., Ltd.) 3103 ") and 70 wt% of calcium oxide (" Moystop # 10 "manufactured by Sankyo Flour Mills Co., Ltd.) and biphenyl aralkyl type epoxy resin (" NC3000 "manufactured by Nippon Kayaku Co., Ltd.) subjected to surface treatment using a stirring surface treatment apparatus. Solid content MEK solution, 35 wt% of phenoxy resin ("YX6954" manufactured by Japan Epoxy Resin Co., Ltd.) EK solution, talc powder (“SG95S” manufactured by Nippon Talc Co., Ltd.) and a coupling agent (“KBM-403” manufactured by Shin-Etsu Silicone Co., Ltd.) were blended and mixed with an Ajihomo mixer Robomix type mixing stirrer (manufactured by Primix). (Mixture H). Mixture H, an ionic liquid curing agent (N-acetylglycine tetrabutylphosphonium salt), and a solvent (MEK, acetone) were mixed and dispersed uniformly with a high-speed rotary mixer to obtain a varnish-like resin composition. . The resin composition varnish is formed on a release film treated surface of a PET film (thickness 38 μm) treated with an alkyd mold release agent so that the thickness of the dried thermosetting resin composition layer is 40 μm. The resin composition sheet | seat was obtained by apply | coating uniformly with a tar and drying at 60-80 degreeC for 6 minute (s).

(Example 2)
A varnish-like resin composition was prepared in the same manner as in Example 1 except that the surface treatment of Moistop # 10 was not performed, and a resin composition sheet was prepared.

Example 3
Liquid core bisphenol A type epoxy resin (Japan Epoxy Resin “828EL”) and orthotoluidine diglycidylamine (Nippon Kayaku Co., Ltd. “GOT”) and acrylic core shell resin (Nippon Zeon Corporation “F351”) Calcium oxide ("Moystop #" manufactured by Sankyo Flour Mills Co., Ltd.) which was surface-treated with a roll-dispersed mixture (mixture G ') and a surface treatment agent ("KBM-3103" manufactured by Shin-Etsu Silicone Co., Ltd.) using a stirring type surface treatment apparatus 10 "), a 70 wt% solid MEK solution of biphenyl aralkyl type epoxy resin (Nippon Kayaku" NC3000 "), a 35 wt% solid MEK solution of phenoxy resin (Japan Epoxy Resin" YX6954 "), talc Powder (“SG95S” manufactured by Nippon Talc Co., Ltd.), coupling agent (“Shin-Etsu Silicone Co., Ltd.“ BM-403 ") were blended and mixed at azide homomixer ROBOMIX type mixing stirrer (manufactured by PRIMIX Corporation) (mixture H '). And this mixture (mixture H '), an ionic liquid hardening | curing agent (N-acetylglycine tetrabutylphosphonium salt), and an organic solvent (MEK, acetone) are mixed, and it disperse | distributes uniformly with a high-speed rotary mixer, and it is varnish-like resin A composition was obtained. Next, the thickness of the resin composition layer after drying is 40 μm on the release treatment surface of a PET film (thickness 38 μm) obtained by treating this varnish-like resin composition with an alkyd mold release agent. The resin composition sheet was obtained by uniformly applying with a die coater and drying at 60 to 80 ° C. for 6 minutes.

Example 4
A varnish-like resin composition was prepared in the same manner as in Example 3 except that the surface treatment of Moistop # 10 was not performed, and a resin composition sheet was prepared.

(Reference Example 1)
A varnish-like resin composition was prepared in the same manner as in Example 4 without using calcium oxide (“Moystop # 10” manufactured by Sankyo Flour Mills), and a resin composition sheet was prepared.

(Comparative Example 1)
Bisphenol A type and F type mixed epoxy resin low chlorine type (“EXA-835LV” manufactured by DIC) and bisphenol A type epoxy resin (“Epicoat 1001” manufactured by Japan Epoxy Resin Co., Ltd.) MEK of 20 wt% solid content of pulverized cyanoethyl-2-phenylimidazolium trimellitate, “2PZ-CNS-PW” manufactured by Shikoku Kasei Co., Ltd., and phenoxy resin (“PKHH” manufactured by InChem) A solution and a silane coupling agent (3-glycidoxypropyltrimethoxysilane: “KBM403” manufactured by Shin-Etsu Silicone Co., Ltd.) were blended in a predetermined amount to obtain a resin composition. Using this resin composition, a resin composition sheet was produced in the same manner as described in Example 1.

(Comparative Example 2)
Bisphenol A-type and F-type mixed epoxy resin low chlorine type (“EXA-835LV” manufactured by DIC), methylhexahydrophthalic anhydride (“Ricacid MH-700” manufactured by Shin Nippon Chemical Co., Ltd.), 1-benzyl-2-methyl A predetermined amount of imidazole (“1B2MZ” manufactured by Shikoku Kasei Co., Ltd.) was mixed to obtain a resin composition. A sheet-like cured product having a thickness of 40 μm was obtained from this resin composition using a mold.

(Comparative Example 3)
Bisphenol A type epoxy resin low chlorine type (“Epicoat 828” manufactured by Japan Epoxy Resin Co., Ltd.), methylhexahydrophthalic anhydride (“Ricacid MH-700” manufactured by Shin Nippon Chemical Co., Ltd.), 1-benzyl-2-methylimidazole (Shikoku) A predetermined amount of “1B2MZ” manufactured by Kasei Co., Ltd.) was mixed to obtain a resin composition. A sheet-like cured product having a thickness of 40 μm was obtained from this resin composition using a mold.
Comparative Examples 2 and 3 correspond to Examples 1 and 2 of Patent Document 2 (Japanese Patent Laid-Open No. 2006-70221).

(Example 5)
A mixture A in which a solid epoxy resin (“HP7200H” manufactured by DIC) was dissolved in a phenoxy resin (“YL7213” manufactured by Japan Epoxy Resin, 35 wt% solid MEK solution) was prepared. On the other hand, a mixture B was prepared by adding and dispersing stearic acid to a MEK slurry (40 wt% as solid content) of calcined dolomite (made by wet grinding from Yoshizawa Lime Company). Mixture A, Mixture B, Talc (“D-600” manufactured by Nippon Talc Co., Ltd., wet pulverized, MEK slurry having a solid content of 30 wt%), rubber fine particle dispersed liquid epoxy resin (“BPA328” manufactured by Nippon Shokubai Co., Ltd.), Contains a latent curing accelerator for epoxy resins ("U-CAT3502T" manufactured by Sun Apro), liquid epoxy resin ("GOT" manufactured by Nippon Kayaku Co., Ltd.), and silane coupling agent ("KBM-403" manufactured by Shin-Etsu Chemical Co., Ltd.) Then, the mixture was mixed with an Ajihomo mixer Robomix type mixing stirrer (manufactured by Primics). An ionic liquid cured product (N-acetylglycine tetrabutylphosphonium salt) was added thereto and dispersed uniformly with a high-speed rotary mixer to obtain a varnish-like resin composition. Using this resin composition, a resin composition sheet was produced in the same manner as described in Example 1.

(Example 6)
A varnish-like resin composition was prepared in the same manner as in Example 5 according to the formulation table in Table 3 below. Using this resin composition, a resin composition sheet was produced in the same manner as described in Example 1.

(Example 7)
A varnish-like resin composition was prepared in the same manner as in Example 5 according to the formulation table in Table 3 below. Using this resin composition, a resin composition sheet was produced in the same manner as described in Example 1.

Various measurement methods and evaluation methods will be described.
1. Measurement and evaluation of low-temperature curability About the resin composition sheets obtained in Examples and Comparative Examples, the tensile shear bond strength to mild steel sheet when the resin composition layer is heat-cured at 120 ° C. for 90 minutes. And evaluated.

First, a mild steel plate (JIS G3141, SPCD, first width: 100 mm × second width: 25 mm × thickness: 1.6 mm) whose surface is polished with an endless belt (JIS # 120) is prepared as shown in FIG. As shown in FIG. 1, the resin composition sheet 12 (first width: 12.5 mm × second width: 25 mm) 12 having a rectangular planar shape is formed on one end portion in the longitudinal direction of one side 11A of the mild steel plate 11. The layer 12A was superposed and laminated by a vacuum laminator under conditions of a temperature of 80 ° C. and a pressure of 1 kgf / cm ² (9.8 × 104 Pa) to produce a test piece 13. Note that two similar test pieces 13 were produced.

Next, as shown in FIG. 3, the two PET films 12B of the two test pieces 13 are peeled, the resin composition layers 12A are opposed to each other, and are bonded so as to overlap each other with a width of 12 mm. It was fixed with a clip so as to be a pressure of / cm ² , and cured by heating at 120 ° C. for 90 minutes. The tensile shear bond strength between the two test pieces was measured with a Tensilon universal tester (TENSILON UTM-5T manufactured by Toyo Seiki Co., Ltd.). The measurement conditions were such that the measurement temperature was 25 ° C. and the tensile speed was 1 mm / min. When the tensile shear bond strength was less than 17 MPa, the low-temperature curability was judged as poor (x), and when it was 17 MPa or more, it was judged good (◯).

2. Measurement and Evaluation of Moisture Permeability Resistance 14 resin composition sheets having a resin composition layer having a thickness of 40 μm obtained in Examples and Comparative Examples were prepared, and these were sequentially laminated under the conditions described in the previous section, thereby forming a resin composition of 14 layers. A laminated sheet material having a total thickness of 500 μm obtained by stacking physical layers was obtained. A cured product obtained by thermally curing this at 120 ° C. for 90 minutes was measured by a method in accordance with JISZ0208 under the conditions of a temperature of 85 ° C., a humidity of 85% RH, and 24 hours, and water vapor per 1 m ² was measured. The amount of permeation was determined. When the water vapor transmission amount is 200 g / m ² · 24 hr or more, the moisture permeability is judged as poor (x), and when it is less than 200 g / m ² · 24 hr and 150 g / m ² · 24 hr or more, the moisture permeability is acceptable (Δ ), The case of less than 150 g / m ² · 24 hr and 100 g / m ² · 24 hr or more was evaluated as good (◯), and the case of less than 100 g / m ² · 24 hr was determined as extremely good (◎).
In addition, the cured product of the laminated sheet material having a thickness of 500 μm was used as the measurement sample, assuming the entire sealing structure of the organic EL element shown in FIG. 1, and the thickness of the cured product of the laminated sheet material (500 μm). Is based on the width (W1 in FIG. 1) of the portion of the curable resin composition layer (cured layer) 6 in FIG. 1 that is in contact with the outside air located on the side of the organic EL element 2.

3. Evaluation of laminating workability The laminating workability was evaluated by the value of the minimum melt viscosity at the time of measuring the temperature rise of the resin composition layer in the resin composition sheets obtained in Examples and Comparative Examples. The minimum melt viscosity is a model Rheosol-G3000 manufactured by UBM, the amount of resin is 1 g, a parallel plate with a diameter of 18 mm is used, a measurement start temperature of 60 ° C., a temperature increase rate of 5 ° C./min, and a measurement temperature of 60 ° C. to Measurement was performed at 200 ° C. and a frequency of 1 Hz / deg. The lowest viscosity value (η) was taken as the lowest melt viscosity. Regarding the laminate processability, an initial minimum melt viscosity of less than 20000 poise was good (◯), and 20000 poise or more was poor (x). When evaluation was not performed, “−” was shown.
Further, two measurements were performed: an initial minimum melt viscosity after film formation and a minimum melt viscosity after storage at 25 ° C. for 24 hours. “Minimum melt viscosity after storage at 25 ° C. for 24 hours” / “initial minimum melt viscosity” was defined as the viscosity retention rate. When the viscosity retention ratio exceeded 1.5, the storage stability was judged as acceptable (Δ), and when it was 1.5 or less, it was judged good (◯).

4). Measurement of Adhesiveness with Substrate Two aluminum foils (width 50 mm, length 50 mm, thickness 50 μm) were prepared, and the resin composition layer (width 40 mm, width 40 mm, 50 mm in length) and laminated by a vacuum laminator under the conditions of a temperature of 80 ° C. and a pressure of 1 kgf / cm ² (9.8 × 10 4 Pa). Then, the support is peeled off, and a second aluminum foil is laminated on the exposed resin composition layer and laminated under the same conditions, and a test piece having a three-layer structure of the aluminum foil, the resin composition layer, and the aluminum foil. It was created. The test piece was heat-cured at 110 ° C. for 30 minutes, then cut into a rectangular test piece having a width of 10 mm and a length of 50 mm, and the length of the test piece was measured in accordance with the T-type peel test method of JIS K-6854. Directional adhesion was measured.

  The above test results are shown in Tables 1, 2, and 3.

  According to the examples and comparative examples, the resin composition of the present invention can be cured at a low temperature of 120 ° C. in a short time to form a cured product layer with high adhesive strength, and the cured product has a sufficiently low moisture permeability for practical use. It turns out that it becomes a thing. Moreover, it turns out that the storage stability of the resin composition sheet | seat for organic EL element sealing improves further by using the hygroscopic metal oxide surface-treated with the surface treating agent. Moreover, it turns out that adhesiveness with a base material improves by containing an inorganic filler from Examples 5-7. Thereby, it turns out that it becomes further useful for sealing of an organic EL element. Therefore, according to the present invention, a resin composition serving as a sealing material capable of forming a highly reliable sealing structure without causing deterioration of the organic EL element, with respect to the organic EL element that is likely to be deteriorated by moisture or heat. It can be seen that a resin composition sheet for sealing an organic EL element can be obtained, and a highly reliable organic EL display device can be provided.

  Since the resin composition of the present invention can be cured quickly at low temperatures to form a cured product having excellent adhesion and low moisture permeability, for example, a sealing resin for a flat panel in addition to the sealing application of an organic EL element It can also be applied to uses such as moisture-proof protective films for printed circuit boards, moisture-proof films for lithium ion batteries, and laminate films for packaging.

1, 4 Glass plate 2 Organic EL element 3 Hygroscopic material 5 Sealing material 6 Curable resin composition layer (cured layer)
7 Sealing base material 11 Mild steel sheet 12 Resin composition sheet 12A Resin composition layer 12B PET film 13 Test piece

  This application is based on Japanese Patent Application No. 2009-013702 filed in Japan, the contents of which are incorporated in full herein.

Claims (5)

  Containing an epoxy resin, a curing agent, a hygroscopic metal oxide having an average particle size of 10 μm or less, and an inorganic filler having an average particle size of 10 μm or less, the inorganic filler comprising silica, barium sulfate, talc, Clay, mica, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, boron nitride, aluminum borate, barium titanate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconic acid A resin composition for sealing an organic EL element, which is one or more selected from barium and calcium zirconate.   The resin composition according to claim 1, wherein the inorganic filler is talc or mica.   The resin composition according to claim 1, wherein the inorganic filler is talc.   A resin composition sheet for sealing an organic EL element, wherein the layer of the resin composition according to any one of claims 1 to 3 is formed on a support.   An organic EL device comprising the resin composition sheet for sealing an organic EL element according to claim 4.