JP2015137338A - Curable composition containing conductive fiber coated particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a curable composition capable of forming a cured product excellent in transparency and conductivity (especially conductivity in a thickness direction) at low cost.SOLUTION: A curable composition contains a conductive fiber coated particle (A) containing a particulate substance and a fibrous conductive material coating the particulate substance, and a curable compound (B) and has a variation coefficient (CV value) of the particulate substance constituting the conductive fiber coated particle (A) of 25 or less and all light transmittance in a visible light wavelength region of a cured product of the curing composition [in terms of thickness 10 μm] of 90% or more.

Description

  The present invention relates to a curable composition containing conductive fiber-coated particles composed of a particulate material and a fibrous conductive material. The said curable composition is useful as a sealing material of an organic electroluminescent element.

  An organic electroluminescence (hereinafter sometimes referred to as “organic EL”) element is composed of a structure in which a light emitting layer is sandwiched between a pair of counter electrodes, and electrons are injected from one electrode and the other electrode. Holes are injected from. Light emission occurs when the injected electrons and holes recombine in the light emitting layer. An organic EL device including the organic EL element is expected as a full-color flat panel display or as an alternative to an LED due to high impact resistance and high visibility and a variety of emission colors. There are two types of light extraction methods for organic EL devices, a top emission type and a bottom emission type. The top emission type is preferable because it has a high aperture ratio and is excellent in light extraction efficiency.

  Organic EL elements are more susceptible to moisture than other electronic components, and the problem is that the moisture that penetrates into the organic EL elements causes oxidation of the electrodes, modification of organic substances, and the like, resulting in a significant decrease in light emission characteristics. It was. As a method for solving this problem, a method of sealing the periphery of the organic EL element with a sealing material having moisture resistance is known. In particular, in the case of the top emission type, since the sealing material is disposed in the light extraction direction, it is required to seal with a sealing material having moisture resistance and transparency.

  And according to the sealing material which has conductivity together with moisture resistance and transparency, the organic EL element can be protected without impairing the light extraction efficiency, and the electrodes can be reliably conductively connected. As a method for imparting conductivity to the sealing material, conductive fine particles obtained by coating a metal on the surface of resin fine particles are blended with an insulating curable compound (for example, a thermosetting compound). The method of hardening is known (refer patent documents 1-4).

Japanese Patent No. 3241276 JP 2000-251536 A JP-A-62-188184 JP-A-10-226773

  However, since the conductive fine particles are coated with metal on the entire surface of the resin fine particles, many expensive metal materials are used and the raw material cost is high. Moreover, since it is necessary to manufacture by special methods, such as an electroplating method and an alternate adsorption method, it was necessary to use a special apparatus or to pass through many processes, and also had the problem that manufacturing cost was high.

  Furthermore, the metal coated resin particles are colored because the entire surface is coated with metal, and in addition, in order to impart conductivity to the cured resin, it is necessary to bring the conductive fine particles into contact with each other in the cured resin. As a result, it was difficult to obtain a cured product having both transparency and conductivity. Furthermore, since the metal-coated resin particles contain a large amount of metal having a high specific gravity, the metal-coated resin particles are likely to precipitate, and it has been difficult to obtain a cured resin that contains the metal-coated resin particles uniformly.

  As a method for imparting conductivity while maintaining the transparency of the cured resin product, a method of coating a conductive ink on the surface of the cured resin product or a method of forming a metal wiring or the like can be considered. According to this method, it is possible to impart conductivity while ensuring the transparency of the cured resin, but it is only possible to impart surface conductivity to the surface of the cured resin, and the cured resin It was impossible to develop conductivity in the thickness direction.

Therefore, the objective of this invention is providing the curable composition which can form the cured | curing material excellent in transparency and electroconductivity (especially electroconductivity to the thickness direction) at low cost.
Another object of the present invention is to provide a cured product having both transparency and conductivity.
Still another object of the present invention is to provide an organic electroluminescence device which is sealed with a cured product having both transparency and conductivity.

As a result of intensive studies to solve the above problems, the present inventors have found the following matters.
1. 1. Conductive fiber-coated particles can be obtained easily and inexpensively by mixing particulate matter and fibrous conductive material. Since the conductive fiber-coated particles can impart conductivity by containing a small amount in the cured product, excellent conductivity (especially conductivity in the thickness direction) is obtained without impairing the transparency of the cured product. 2. What can be granted 3. Conductive fiber-coated particles have a low specific gravity and high dispersibility because they contain less metal than metal-coated resin particles. When the variation in the size of the particulate matter constituting the conductive fiber-coated particles is reduced, excellent conductivity can be imparted in a smaller amount, and a cured product having both superior transparency and conductivity can be obtained. The present invention has been completed based on these findings.

  That is, the present invention is a curable composition comprising conductive fiber-coated particles (A) containing a particulate material and a fibrous conductive material that coats the particulate material, and a curable compound (B). The variation coefficient (CV value) of the particulate matter constituting the conductive fiber-coated particles (A) is 25 or less, and the total light transmittance [thickness in the visible light wavelength region of the cured product of the curable composition] Provided is a curable composition characterized by having a ratio of 10 μm] of 90% or more.

  The present invention also provides the curable composition, wherein the fibrous conductive material constituting the conductive fiber-coated particles (A) is a conductive nanowire.

  The present invention also provides the curable composition, wherein the conductive nanowire is at least one selected from the group consisting of metal nanowires, semiconductor nanowires, carbon fibers, carbon nanotubes, and conductive polymer nanowires.

  The present invention also provides the curable composition as described above, wherein the conductive nanowire is a silver nanowire.

  The present invention also provides the curable composition described above, wherein the fibrous conductive material constituting the conductive fiber-coated particles (A) has an average diameter of 1 to 400 nm and an average length of 1 to 100 μm. To do.

  The present invention also provides the above curable composition, wherein the average particle diameter of the particulate material constituting the conductive fiber-coated particles (A) is 0.1 to 100 μm.

  The present invention also provides the curable composition, wherein the content of the fibrous conductive material is 0.01 to 1.0 part by weight with respect to 100 parts by weight of the curable compound (B).

  The present invention also provides the above curable composition, wherein the curable compound (B) contains a compound having at least an alicyclic structure and an epoxy group in one molecule.

The present invention also provides the curable composition, wherein the curable compound (B) includes at least a compound represented by the following formula (I).
(In the formula, R ^{1 to} R ¹⁸ are the same or different and each represents a hydrogen atom, a halogen atom, an oxygen atom, a hydrocarbon group that may contain a halogen atom, or an alkoxy group that may have a substituent. , X represents a single bond or a connecting group)

  The present invention also provides a conductive encapsulant for encapsulating an organic electroluminescence element comprising the curable composition.

  The present invention also provides a conductive sealant for sealing a top emission type organic electroluminescence device comprising the curable composition.

  The present invention also provides a cured product obtained by curing the curable composition.

  The present invention also provides the above-described cured product having a total light transmittance [converted to a thickness of 10 μm] in a visible light wavelength region of 90% or more.

  The present invention also provides the above cured product having an electrical resistivity (at 25 ° C. and 1 atm) of 0.1 Ω · cm to 10 MΩ · cm.

  The present invention also provides an organic electroluminescence device in which an organic electroluminescence element is sealed with the cured product.

  Since the curable composition of the present invention contains conductive fiber-coated particles that can impart excellent conductivity (particularly conductivity in the thickness direction) to the cured product even with a small amount of addition, it is excellent. A cured product having excellent transparency and excellent conductivity (particularly conductivity in the thickness direction) can be formed. In addition, the conductive fiber-coated particles can be produced by a simple process without using a special device, and in addition, a large amount of expensive conductive material (material having conductivity) is used as a raw material. Since it is not necessary, the curable composition of the present invention can reduce raw material costs and can be provided at low cost.

  And when the conductive fiber-coated particles having flexibility are included as the conductive fiber-coated particles, the flexible conductive fiber-coated particles may be deformed following the uneven structure and spread to the details. Therefore, generation | occurrence | production of the part from which electroconductivity becomes poor can be prevented, and the hardened | cured material excellent in electroconductivity can be obtained.

  Therefore, the curable composition of this invention can be used conveniently as a sealing material of an organic EL element (especially top emission type organic EL element). In addition, the sheet | seat or film which consists of a curable composition of this invention can be used conveniently as a sheet | seat or film for sealing of an organic EL element (especially top emission type organic EL element).

  Furthermore, the organic EL device of the present invention sealed with the curable composition or a sealing sheet or film comprising the curable composition is excellent in light extraction efficiency (that is, excellent in light emission efficiency), and excellent. Have high brightness.

It is an example of the scanning electron microscope image (SEM image) of the conductive fiber covering particle | grains (conductive fiber covering particle | grains of this invention) obtained in Example 1. FIG. It is the schematic which shows an example of the manufacturing method of the organic EL device using the curable composition of this invention.

[Conductive fiber coated particles (A)]
The conductive fiber-coated particles of the present invention include a conductive material including a particulate material and a fibrous conductive material that coats the particulate material (sometimes referred to herein as “conductive fiber”). Coated particles. In the conductive fiber-coated particles of the present invention, “cover” means a state in which the conductive fibers cover part or all of the surface of the particulate matter. In the conductive fiber-coated particles of the present invention, it is only necessary that the conductive fibers cover at least a part of the surface of the particulate matter. For example, there are more uncovered portions than covered portions. You may do it. In the conductive fiber-coated particles of the present invention, the particulate matter and the conductive fiber are not necessarily in contact with each other, but usually a part of the conductive fiber is in contact with the surface of the particulate matter. Yes.

  FIG. 1 is an example of a scanning electron microscope image of the conductive fiber-coated particles of the present invention. As shown in FIG. 1, in the conductive fiber-coated particles of the present invention, at least a part of the particulate material (the true spherical material in FIG. 1) is coated with the conductive fiber (the fibrous material in FIG. 1). It has a configuration.

(Particulate matter)
The particulate matter constituting the conductive fiber-coated particles of the present invention is a particulate structure.

  The material (raw material) constituting the particulate matter is not particularly limited, and examples thereof include known or commonly used materials such as metal, plastic, rubber, ceramic, glass, and silica. In the present invention, it is particularly preferable to use a transparent material such as transparent plastic, glass, and silica, and it is particularly preferable to use a transparent plastic.

  The transparent plastic includes a thermosetting resin and a thermoplastic resin. Examples of the thermosetting resin include poly (meth) acrylate resin; polystyrene resin; polycarbonate resin; polyester resin; polyurethane resin; epoxy resin; polysulfone resin; amorphous polyolefin resin; divinylbenzene, hexatriene, divinyl ether, Divinyl sulfone, diallyl carbinol, alkylene diacrylate, oligo or polyalkylene glycol diacrylate, oligo or polyalkylene glycol dimethacrylate, alkylene triacrylate, alkylene tetraacrylate, alkylene trimethacrylate, alkylene tetramethacrylate, alkylene bisacrylamide, alkylene bismethacryl Multifunctional monomers such as amide and polybutadiene oligomer modified with both ends Germany or polymerized with other monomers obtained network polymer; phenol formaldehyde resins, melamine formaldehyde resins, benzoguanamine-formaldehyde resins, and urea-formaldehyde resins. Examples of the thermoplastic resin include ethylene / vinyl acetate copolymer, ethylene / vinyl acetate / unsaturated carboxylic acid copolymer, ethylene / ethyl acrylate copolymer, ethylene / methyl methacrylate copolymer, and ethylene / acrylic acid. Copolymer, ethylene / methacrylic acid copolymer, ethylene / maleic anhydride copolymer, ethylene / aminoalkyl methacrylate copolymer, ethylene / vinyl silane copolymer, ethylene / glycidyl methacrylate copolymer, ethylene / hydroxyethyl methacrylate Examples include copolymers, methyl (meth) acrylate / styrene copolymers, acrylonitrile / styrene copolymers, and the like.

  The shape of the particulate material is not particularly limited. For example, it is spherical (true sphere, approximately true sphere, elliptical sphere, etc.), polyhedron, rod (column, prism, etc.), flat plate, flake shape, indefinite Examples include shape. In the present invention, in particular, the conductive fiber-coated particles can be produced with high productivity, can be easily dispersed uniformly with the curable compound, and can be easily imparted with conductivity to the entire cured product. A rod shape is preferable, and a spherical shape (particularly a true spherical shape) is particularly preferable.

  Although the average aspect-ratio of the said particulate matter is not specifically limited, Less than 20 (for example, 1 or more and less than 20) is preferable, Most preferably, it is 1-10. When the average aspect ratio exceeds the above range, it may be difficult to develop excellent conductivity in the curable compound by blending a small amount of conductive fiber-coated particles. Note that the average aspect ratio of the particulate matter is, for example, a sufficient number (for example, 100 or more, preferably 300 or more; in particular, 100 or 300) using an electron microscope (SEM, TEM). It is obtained by taking an electron microscope image of the particulate matter, measuring the aspect ratio of these particulate matter, and arithmetically averaging them.

  Moreover, the structure of the said particulate matter is not specifically limited, A single layer structure may be sufficient and a multilayer (multilayer) structure may be sufficient. The particulate matter may be any of solid particles, hollow particles, porous particles, and the like.

The particulate matter has a sharp particle size distribution (that is, there is little variation in particle size), and the coefficient of variation (CV value) is 25 or less (particularly preferably 20 or less, most preferably 10 or less). Therefore, compared with the case where the conductive fiber covering particle | grains containing the particulate substance which has a broad particulate distribution are used, the outstanding electroconductivity can be provided with a smaller usage-amount. The coefficient of variation in the volume-based particle size distribution of the particulate matter is calculated from the following equation. The particle size distribution can be measured using a particle size distribution measuring device (trade name “Coulter Multisizer” manufactured by Beckman Coulter, Inc.).
Coefficient of variation (CV value) (%) = (S2 / Dn) × 100
(In the formula, S2 represents the standard deviation in the volume-based particle size distribution, and Dn represents the median diameter (D50) based on the volume)

  Furthermore, the average particle diameter of the particulate material is not particularly limited, but is preferably 0.1 to 100 μm, particularly preferably 1 to 50 μm, and most preferably 5 to 30 μm. When the average particle diameter is below the above range, it may be difficult to develop excellent conductivity by blending a small amount of conductive fiber-coated particles. On the other hand, when the average particle diameter exceeds the above range, the average particle diameter becomes larger than the thickness of the sealing layer of the organic EL element, and it tends to be difficult to form a coating film having a uniform thickness. When the particulate matter has an anisotropic shape, it is preferable that the average particle diameter in the long axis (longest long axis) direction is controlled within the above range. In addition, the average particle diameter of the said particulate matter is a median diameter (D50) by a laser diffraction / scattering method.

  The particulate material is preferably transparent. Specifically, the total light transmittance in the visible light wavelength region of the particulate matter is not particularly limited, but is preferably 70% or more, and particularly preferably 75% or more. When the total light transmittance is below the above range, the transparency of the cured product (including the conductive fiber-coated particles) may be lowered. The total light transmittance in the visible light wavelength region of the particulate matter is, when the particulate matter is a plastic particle, the monomer as the raw material of the particulate matter at a temperature of 80 to 150 ° C. between the glasses. Polymerization is performed in a region to obtain a flat plate having a thickness of 1 mm, and the total light transmittance in the visible light wavelength region of the flat plate is measured according to JIS K7361-1.

The particulate matter preferably has flexibility, and the 10% compressive strength is, for example, 10 kgf / mm ² or less, preferably 5 kgf / mm ² or less. The conductive fiber-coated particles containing particulate matter having a 10% compressive strength in the above range can be deformed following a fine concavo-convex structure by applying pressure. Therefore, when the curable composition containing the conductive fiber-coated particles is used for sealing an organic EL device having a fine concavo-convex structure, the conductive fiber-coated particles can be distributed in detail, Generation | occurrence | production of the part which becomes inferior property can be prevented, and the hardened | cured material excellent in electroconductivity can be obtained.

  The refractive index of the particulate material is not particularly limited, but is preferably 1.4 to 2.7, and particularly preferably 1.4 to 1.8. The refractive index of the particulate matter is determined by polymerizing a monomer that is a raw material of the particulate matter in a temperature range of 80 to 150 ° C. between the glasses when the particulate matter is a plastic particle. A 1 mm flat plate was obtained, and a 20 mm long x 6 mm wide test piece was cut out from the obtained flat plate, and the multi-wavelength Abbe refraction was carried out using monobromonaphthalene as an intermediate solution in close contact with the prism and the test piece. Using a meter (trade name “DR-M2”, manufactured by Atago Co., Ltd.), the refractive index can be determined by measuring the refractive index at 25 ° C. and sodium D line.

Moreover, it is preferable that the said particulate matter has a small refractive index difference with the hardened | cured material of the sclerosing | hardenable compound (B) mentioned later, and hardening of the particulate matter and curable compound (B) which comprise electroconductive fiber covering particle | grains The absolute value of the refractive index difference (at 25 ° C., wavelength 589.3 nm) of the object is, for example, 0.1 or less (preferably 0.08 or less, particularly preferably 0.02 or less). That is, the refractive index of the cured product of the conductive fiber-coated particles and the curable compound (B) contained in the curable composition of the present invention preferably satisfies the following formula.
Refractive index of particulate matter (at 25 ° C., wavelength of 589.3 nm) -refractive index of cured product of curable compound (B) (at 25 ° C., wavelength of 589.3 nm) | ≦ 0.1

  The particulate matter can be produced by a known or conventional method, and the production method is not particularly limited. For example, in the case of metal particles, it can be produced by a vapor phase method such as a CVD method or a spray pyrolysis method, or a wet method using a chemical reduction reaction. In the case of plastic particles, for example, a method of polymerizing monomers constituting the resin (polymer) exemplified above by a known polymerization method such as a suspension polymerization method, an emulsion polymerization method, a seed polymerization method, or a dispersion polymerization method. Etc. can be manufactured.

  In the present invention, commercially available products can also be used. Examples of particulate substances made of thermosetting resins include trade names “Techpolymer MBX series”, “Techpolymer BMX series”, “Techpolymer ABX series”, “Techpolymer ARX series”, and “Techpolymer AFX series”. (Sekisui Plastics Industry Co., Ltd.), trade names "Micropearl SP", "Micropearl SI" (Sekisui Chemical Co., Ltd.); The trade name “Soft Bead” (manufactured by Sumitomo Seika Co., Ltd.), the trade name “Duo Master” (manufactured by Sekisui Plastics Co., Ltd.), and the like can be used.

(Fibrous conductive material (conductive fiber))
The conductive fiber constituting the conductive fiber-coated particle of the present invention is a fibrous structure (linear structure) having conductivity. The shape of the conductive fiber is not particularly limited as long as it is fibrous (fibrous), but the average aspect ratio is preferably 10 or more (for example, 20 to 5000), particularly preferably 50 to 3000, and most preferably. Is 100-1000. When the average aspect ratio is less than the above range, it may be difficult to develop excellent conductivity by blending a small amount of conductive fiber-coated particles. The average aspect ratio of the conductive fiber is determined by the same procedure as that for the average aspect ratio of the particulate matter. Note that the concept of “fibrous” in the conductive fibers includes shapes of various linear structures such as “wire” and “rod”. In the present specification, fibers having an average thickness of 1000 nm or less may be referred to as “nanowires”.

  The average thickness (average diameter) of the conductive fibers is not particularly limited, but is preferably 1 to 400 nm, particularly preferably 10 to 200 nm, and most preferably 50 to 150 nm. When the average thickness is less than the above range, the conductive fibers are likely to aggregate and it may be difficult to produce the conductive fiber-coated particles. On the other hand, if the average thickness exceeds the above range, it may be difficult to coat the particulate matter, and it may be difficult to obtain conductive fiber-coated particles efficiently. The average thickness of the conductive fibers is an electron with respect to a sufficient number of conductive fibers (for example, 100 or more, preferably 300 or more; in particular, 100 or 300) using an electron microscope (SEM, TEM). It is calculated | required by image | photographing a microscope image, measuring the thickness (diameter) of these electroconductive fibers, and carrying out arithmetic average.

Although the average length of the said conductive fiber is not specifically limited, 1-100 micrometers is preferable, Especially preferably, it is 5-80 micrometers, Most preferably, it is 10-50 micrometers. If the average length is less than the above range, it may be difficult to coat the particulate matter, and it may not be possible to obtain conductive fiber-coated particles efficiently. On the other hand, if the average length exceeds the above range, the conductive fibers may adhere to or be adsorbed on a plurality of particles, which may cause aggregation (deterioration of dispersibility) of the conductive fiber-coated particles. The average length of the conductive fibers is an electron for a sufficient number of conductive fibers (for example, 100 or more, preferably 300 or more; in particular, 100 or 300) using an electron microscope (SEM, TEM). It is calculated | required by image | photographing a microscope image, measuring the length of these electroconductive fibers, and carrying out arithmetic average. Note that the length of the conductive fiber should be measured in a linearly stretched state, but in reality it is often bent so that the conductive fiber can be measured using an image analyzer from an electron microscope image. The projected diameter and projected area are calculated and calculated from the following equation assuming a cylindrical body.
Length = projected area / projected diameter

  The material (raw material) constituting the conductive fiber may be a conductive material, and examples thereof include metals, semiconductors, carbon materials, and conductive polymers.

  Examples of the metal include known or commonly used metals such as gold, silver, copper, iron, nickel, cobalt, tin, and alloys thereof. In the present invention, silver is particularly preferable in terms of excellent conductivity.

  Examples of the semiconductor include known or commonly used semiconductors such as cadmium sulfide and cadmium selenide.

  Examples of the carbon material include known or conventional carbon materials such as carbon fibers and carbon nanotubes.

  Examples of the conductive polymer include polyacetylene, polyacene, polyparaphenylene, polyparaphenylene vinylene, polypyrrole, polyaniline, polythiophene, and derivatives thereof (for example, an alkyl group, a hydroxyl group, a carboxyl group, a common polymer skeleton, And those having a substituent such as ethylenedioxy group; specifically, polyethylenedioxythiophene and the like). In the present invention, polyacetylene, polyaniline and derivatives thereof, polypyrrole and derivatives thereof, polythiophene and derivatives thereof are particularly preferable. The conductive polymer may contain a known or commonly used dopant (for example, an acceptor such as a halogen, a halide or a Lewis acid; a donor such as an alkali metal or an alkaline earth metal).

  The conductive fiber of the present invention is preferably a conductive nanowire, in particular, at least one conductive nanowire selected from the group consisting of metal nanowires, semiconductor nanowires, carbon fibers, carbon nanotubes, and conductive polymer nanowires, In particular, silver nanowires are most preferable in terms of excellent conductivity.

  The conductive fiber can be produced by a known or conventional production method. For example, the metal nanowire can be manufactured by a liquid phase method, a gas phase method, or the like. More specifically, silver nanowires are, for example, Mater. Chem. Phys. 2009, 114, 333-338, Adv. Mater. 2002, 14, P833-837, Chem. Mater. 2002, 14, P4736-4745, It can be produced by the method described in Table 2009-505358. In addition, the gold nanowire can be manufactured, for example, by the method described in JP-A-2006-233252. Moreover, a copper nanowire can be manufactured by the method as described in Unexamined-Japanese-Patent No. 2002-266007, for example. Moreover, cobalt nanowire can be manufactured by the method as described in Unexamined-Japanese-Patent No. 2004-148771, for example. Furthermore, a semiconductor nanowire can be manufactured by the method as described in Unexamined-Japanese-Patent No. 2010-208925, for example. The carbon fiber can be produced, for example, by the method described in JP-A-06-081223. The carbon nanotube can be produced, for example, by the method described in JP-A-06-157016. The said conductive polymer nanowire can be manufactured by the method of Unexamined-Japanese-Patent No. 2006-241334, Unexamined-Japanese-Patent No. 2010-76044, for example. A commercial item can also be used as the conductive fiber.

(Method for producing conductive fiber-coated particles)
The conductive fiber-coated particles (A) can be produced by mixing the above-mentioned particulate material and conductive fibers in a solvent. For example, any one of the following methods (1) to (4) Can be manufactured.
(1) Mixing a dispersion in which the particulate matter is dispersed in a solvent (referred to as “particle dispersion”) and a dispersion in which the conductive fibers are dispersed in a solvent (referred to as “fiber dispersion”). Then, if necessary, the solvent is removed to obtain the conductive fiber-coated particles of the present invention (or a dispersion of the conductive fiber-coated particles).
(2) After blending and mixing the conductive fibers in the particle dispersion, the solvent is removed if necessary, and the conductive fiber-coated particles of the present invention (or a dispersion of the conductive fiber-coated particles). Get.
(3) After blending and mixing the particulate matter with the fiber dispersion, the solvent is removed if necessary, and the conductive fiber-coated particles of the present invention (or a dispersion of the conductive fiber-coated particles). Get.
(4) After mixing and mixing the particulate matter and the conductive fibers in a solvent, the solvent is removed as necessary to disperse the conductive fiber-coated particles of the present invention (or dispersion of the conductive fiber-coated particles). Liquid).
In the present invention, among these, the method (1) is preferable because homogeneous conductive fiber-coated particles can be obtained.

  Examples of the solvent used in producing the conductive fiber-coated particles of the present invention include water; alcohols such as methanol, ethanol, propanol, isopropanol, and butanol; acetone, methyl ethyl ketone (MEK), and methyl isobutyl ketone (MIBK). Ketones such as benzene, toluene, xylene and ethylbenzene; ethers such as diethyl ether, dimethoxyethane, tetrahydrofuran and dioxane; esters such as methyl acetate, ethyl acetate, isopropyl acetate and butyl acetate; N, N- Examples thereof include amides such as dimethylformamide and N, N-dimethylacetamide; nitriles such as acetonitrile, propionitrile and benzonitrile. These can be used individually by 1 type or in combination of 2 or more types (that is, as a mixed solvent). In the present invention, alcohol and ketone are particularly preferable.

  Moreover, if the curable compound (B) described later is in a liquid form (for example, an epoxy compound), it can be used as the solvent. By using a liquid curable compound as a solvent, a curable composition containing the curable compound and the conductive fiber-coated particles can be obtained without going through the step of removing the solvent.

  Although the viscosity of the solvent is not particularly limited, the viscosity at 25 ° C. is preferably 10 cP or less (for example, 0.1 to 10 cP) in that the conductive fiber-coated particles can be efficiently produced, Particularly preferred is 0.5 to 5 cP. The viscosity of the solvent at 25 ° C. can be measured using, for example, an E-type viscometer (rotor: 1 ° 34 ′ × R24, rotation speed: 0.5 rpm, measurement temperature: 25 ° C.).

  The boiling point of the solvent at 1 atm is preferably 200 ° C. or less, particularly preferably 150 ° C. or less, and most preferably 120 ° C. or less, from the viewpoint that the conductive fiber-coated particles can be efficiently produced.

  The content of the particulate matter when mixing the particulate matter and the conductive fiber in the solvent is, for example, about 0.1 to 50 parts by weight, preferably 1 to 30 parts by weight with respect to 100 parts by weight of the solvent. The content of the conductive fiber is, for example, about 0.1 to 50 parts by weight, preferably 1 to 30 parts by weight with respect to 100 parts by weight of the solvent. By controlling the content of the particulate matter and the conductive fibers within the above range, the conductive fiber-coated particles can be more efficiently produced.

  The ratio of the particulate matter and the conductive fiber when mixing the particulate matter and the conductive fiber in the solvent is the ratio of the surface area of the particulate matter to the projected area of the conductive fiber [surface area / projected area]. However, the ratio is preferably about 100/1 to 100/100, preferably 100/5 to 100/50. By controlling the ratio within the above range, the conductive fiber-coated particles can be generated more efficiently. In addition, the surface area of the said particulate matter is calculated | required by the method of multiplying the specific surface area calculated | required by BET method (based on JISZ8830) by the mass (usage amount) of a particulate matter. Further, as described above, the projected area of the conductive fibers is a sufficient number (for example, 100 or more, preferably 300 or more; in particular, 100 or 300) using an electron microscope (SEM, TEM). This is obtained by taking an electron microscope image of the conductive fibers, calculating the projected area of these conductive fibers using an image analyzer, and calculating the arithmetic average.

  After mixing the particulate matter and the conductive fibers, the conductive fiber-coated particles can be obtained as a solid by removing the solvent. The removal of the solvent is not particularly limited, and can be performed by a known or conventional method such as heating, distillation under reduced pressure, or the like. The solvent is not necessarily removed, and can be used as it is, for example, as a dispersion of conductive fiber-coated particles.

  As described above, the conductive fiber-coated particles can be produced by mixing raw materials (particulate matter and conductive fibers) in a solvent, and do not require a complicated process. It is advantageous.

  In particular, as a combination of particulate matter and conductive fiber, particulate matter having an average particle diameter A [μm] and an average length A [μm] or more (preferably A × 0.5 [μm] or more, particularly preferably A By using conductive fibers having a size of 1.0 [μm] or more, most preferably A × 1.5 [μm] or more, conductive fiber-coated particles can be produced more efficiently. In particular, in the case of a spherical or substantially spherical particulate material, a particulate material having an average circumference B [μm] and an average length (B × 1/6) [μm] or more (preferably B [μm It is preferable to use the above-mentioned conductive fibers. The average perimeter of the particulate matter is a sufficient number (for example, 100 or more, preferably 300 or more; in particular, 100, 300, etc.) using an electron microscope (SEM, TEM). It is obtained by taking an electron microscope image of the substance, measuring the circumference of these particulate substances, and calculating the arithmetic average.

  The ratio of the particulate matter and the conductive fiber constituting the conductive fiber-coated particle of the present invention is such that the ratio of the surface area of the particulate matter and the projected area of the conductive fiber [surface area / projected area] is, for example, 100/1 to It is preferable that the ratio is about 100/100 (particularly 100/5 to 100/50) in that the conductivity can be imparted more efficiently while ensuring the transparency of the cured product. In addition, the surface area of the particulate matter and the projected area of the conductive fiber are determined by the above-described methods.

  Since the conductive fiber-coated particles of the present invention have the above-described configuration, excellent conductivity (particularly, conductivity in the thickness direction) can be imparted by adding a small amount to the cured product, and transparency and conductivity. It is possible to form an excellent cured product.

Then, when the conductive fiber coated particles of the present invention has flexibility (for example, if a 10% compression strength of 5 kgf / mm ² or less), fine irregularities of the curable composition including the conductive fibers coated particles When used as a sealing material for organic EL devices having a conductive layer, the conductive fiber-coated particles can be deformed following the concavo-convex structure and spread to details, thus preventing the occurrence of defective conductivity. It is possible to form an organic EL device having excellent conductive performance.

  The conductive fiber-coated particles (A) can be used alone or in combination of two or more. The content (blending amount) of the conductive fiber-coated particles (A) in the curable composition is, for example, about 0.01 to 30 parts by weight, preferably 0.1 with respect to 100 parts by weight of the curable compound (B). -20 parts by weight, more preferably 0.3-15 parts by weight, particularly preferably 0.5-5 parts by weight. When content of electroconductive fiber covering particle | grains is less than the said range, depending on a use, the electroconductivity of the hardened | cured material obtained may become inadequate. On the other hand, when the content of the conductive fiber-coated particles exceeds the above range, the transparency of the obtained cured product may be insufficient depending on the application.

  The content of the conductive fiber-coated particles (A) in the curable composition is preferably 0.1 to 60% by volume, more preferably 0.2%, based on the total amount (100% by volume) of the curable composition. -60% by volume, particularly preferably 0.3-50% by volume, most preferably 0.3-40% by volume.

  In particular, in the case of developing anisotropic conductivity (electric anisotropy that has conductivity in a specific direction but is insulative in other directions), the conductive fiber coating in the curable composition The content of the particles is preferably 30% by volume or less (for example, 0.1 to 10% by volume), particularly preferably 0.3 to 5% by volume with respect to the total amount (100% by volume) of the curable composition. is there. By adjusting the content of the conductive fiber-coated particles to the above range, excellent conductivity in a specific direction can be exhibited. The content of the conductive fiber-coated particles can be estimated by dividing the total weight of the conductive fiber-coated particles by the density of the particles (conductive fiber-coated particles), for example.

  The content (particulate amount) of the particulate matter (particulate matter contained in the conductive fiber-coated fine particles) in the curable composition is, for example, 0.09 to 6.5 with respect to 100 parts by weight of the curable compound (B). About 0 parts by weight, preferably 0.1 to 4.0 parts by weight, more preferably 0.3 to 3.5 parts by weight, still more preferably 0.3 to 3.0 parts by weight, and particularly preferably 0.3 to 3.0 parts by weight. 2.5 parts by weight, most preferably 0.5 to 2.0 parts by weight, for example, about 0.02 to 7% by volume, preferably about 0.02 to 7% by volume with respect to the total amount (100% by volume) of the curable composition. It is 1 to 5% by volume, particularly preferably 0.3 to 3% by volume, and most preferably 0.4 to 2% by volume. When content of the said particulate matter is less than the said range, depending on a use, the electroconductivity of the obtained hardened | cured material may become inadequate. On the other hand, if the content of the particulate matter exceeds the above range, the resulting cured product may have insufficient transparency depending on the application.

  The content (blending amount) of the conductive fiber in the curable composition is, for example, about 0.01 to 1.0 part by weight, preferably 0.02 to 0.02 parts per 100 parts by weight of the curable compound (B). 8 parts by weight, more preferably 0.03 to 0.6 parts by weight, particularly preferably 0.03 to 0.4 parts by weight, and most preferably 0.03 to 0.2 parts by weight. 0.01-1.1 volume% is preferable with respect to the whole quantity (100 volume%), More preferably, it is 0.02-0.9 volume%, Most preferably, it is 0.03-0.7 volume%, Most preferably Is 0.03-0.4 volume%.

  Since the curable composition of the present invention is contained in a state in which conductive fibers are coated on a particulate material having a small size variation, sufficient conductivity can be achieved even when the amount of the conductive material used is reduced to the above range. A cured product having properties can be formed. Therefore, it is possible to reduce the decrease in transparency of the cured product caused by containing a material having conductivity, and it is possible to greatly reduce the cost occupied by the material having conductivity. .

[Curable compound (B)]
As the curable compound of the present invention, a cationic curable compound is preferable, and an epoxy compound is particularly preferable in that a cured product having excellent transparency and mechanical properties can be obtained. Examples of the epoxy compound include an aromatic glycidyl ether epoxy compound; an aliphatic glycidyl ether epoxy compound; a glycidyl ester epoxy compound; a glycidyl amine epoxy compound; and an alicyclic epoxy compound.

  Examples of the aromatic glycidyl ether epoxy compound include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, biphenol type epoxy compounds, phenol novolac type epoxy compounds, cresol novolac type epoxy compounds, and bisphenol A cresol novolac type epoxy compounds. , Naphthalene type epoxy compounds, trisphenol methane type epoxy compounds and the like.

  Examples of the aliphatic glycidyl ether-based epoxy compound include mono- or polyglycidyl ethers of aliphatic polyhydric alcohols such as polyethylene glycol, polypropylene glycol, glycerin, tetramethylene glycol, and 1,6-hexanediol. .

  Examples of the alicyclic epoxy compound [compound having at least an alicyclic (aliphatic ring) structure and an epoxy group in the molecule (in one molecule)] (i) two adjacent carbons constituting the alicyclic ring A compound having an epoxy group (alicyclic epoxy group) composed of an atom and an oxygen atom, (ii) a compound in which an epoxy group is directly bonded to the alicyclic ring by a single bond, and (iii) a hydrogenated glycidyl ether epoxy compound Etc.

  Examples of the compound (i) having an alicyclic epoxy group include compounds represented by the following formula (I).

In the above formula (I), R ^{1 to} R ¹⁸ are the same or different and are a hydrogen atom, a halogen atom, an oxygen atom, a hydrocarbon group which may contain a halogen atom, or an alkoxy which may have a substituent. Indicates a group.

As a halogen atom in R < ¹ > -R < ¹⁸ >, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom etc. can be mentioned, for example.

Examples of the hydrocarbon group in R ^{1 to} R ¹⁸ include an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group in which two or more of these are bonded.

Examples of the aliphatic hydrocarbon group include a C _1-20 alkyl group (preferably a C _1-10 alkyl group, particularly a methyl, ethyl, propyl, isopropyl, butyl, hexyl, octyl, isooctyl, decyl, dodecyl group). Preferably a C _1-4 alkyl group); vinyl, allyl, methallyl, 1-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl C _2-20 alkenyl group such as 5-hexenyl group (preferably C _2-10 alkenyl group, particularly preferably C _2-4 alkenyl group; C _2-20 alkynyl group such as ethynyl, propynyl group (preferably C _{2 -10} alkynyl group, particularly preferably a C _2-4 alkynyl group).

Examples of the alicyclic hydrocarbon group include C _3-12 cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cyclododecyl groups; C _3-12 cycloalkenyl groups such as cyclohexenyl groups; and bicycloheptanyl. And a C _4-15 bridged cyclic hydrocarbon group such as a bicycloheptenyl group.

Examples of the aromatic hydrocarbon group include C _6-14 aryl groups (preferably C _6-10 aryl groups) such as phenyl and naphthyl groups.

Examples of the group in which two or more groups selected from the above aliphatic hydrocarbon group, alicyclic hydrocarbon group, and aromatic hydrocarbon group are bonded include, for example, C _3-12 cyclohexane such as cyclohexylmethyl group. Alkyl-C _1-20 alkyl group; C _1-20 alkyl-C _3-12 cycloalkyl group such as methylcyclohexyl group; C _7-18 aralkyl group such as benzyl group and phenethyl group (especially C _7-10 aralkyl group) C _6-14 aryl-C _2-20 alkenyl group such as cinnamyl group; C _1-20 alkyl substituted C _6-14 aryl group such as tolyl group; C _2-20 alkenyl substituted C _6-14 such as styryl group An aryl group etc. can be mentioned.

Examples of the hydrocarbon group that may contain an oxygen atom or a halogen atom in R ^{1 to} R ¹⁸ include a group in which at least one hydrogen atom in the above-described hydrocarbon group is substituted with a group having an oxygen atom or a halogen atom, etc. Can be mentioned. Examples of the group having an oxygen atom include hydroxyl group; hydroperoxy group; C _1-10 alkoxy group such as methoxy, ethoxy, propoxy, isopropyloxy, butoxy, isobutyloxy group; C _2-10 such as allyloxy group. An alkenyloxy group; a C _6-14 aryloxy group optionally having a substituent selected from a C _1-10 alkyl group, a C _2-10 alkenyl group, a halogen atom, and a C _1-10 alkoxy group (for example, C _7-18 aralkyloxy groups such as benzyloxy and phenethyloxy groups; C _1-10 acyloxy groups such as acetyloxy, propionyloxy, (meth) acryloyloxy and benzoyloxy groups; methoxy carbonyl, ethoxycarbonyl, propoxycarbonyl, C _1-10 aralkyl such as a butoxycarbonyl group Alkoxycarbonyl group; C _1-10 alkyl group, C _2-10 alkenyl group, a halogen atom, and C _1-10 may have a substituent group selected from an alkoxy group C _6-14 aryloxycarbonyl group ( For example, phenoxycarbonyl, tolyloxycarbonyl, naphthyloxycarbonyl group, etc.); C _7-18 aralkyloxycarbonyl group such as benzyloxycarbonyl group; epoxy group-containing group such as glycidyloxy group; oxetanyl group such as ethyloxetanyloxy group Groups: C _1-10 acyl groups such as acetyl, propionyl and benzoyl groups; isocyanate groups; sulfo groups; carbamoyl groups; oxo groups; and two or more of these via or without C _1-10 alkylene groups Examples thereof include a bonded group.

Examples of the alkoxy group in R ^{1 to} R ¹⁸ include C _1-10 alkoxy groups such as methoxy, ethoxy, propoxy, isopropyloxy, butoxy, and isobutyloxy groups.

Examples of the substituent that the alkoxy group may have include, for example, a halogen atom, a hydroxyl group, a C _1-10 alkoxy group, a C _2-10 alkenyloxy group, a C _6-14 aryloxy group, a C _1-10 Acyloxy group, mercapto group, C _1-10 alkylthio group, C _2-10 alkenylthio group, C _6-14 arylthio group, C _7-18 aralkylthio group, carboxyl group, C _1-10 alkoxycarbonyl group, C _{6- 14} aryloxycarbonyl group, C _7-18 aralkyloxycarbonyl group, amino group, mono or di C _1-10 alkylamino group, C _1-10 acylamino group, epoxy group-containing group, oxetanyl group-containing group, C _1-10 Examples include an acyl group, an oxo group, and a group in which two or more of these are bonded through or without a C _1-10 alkylene group.

  In the above formula (I), X represents a single bond or a connecting group (a divalent group having one or more atoms). Examples of the connecting group include a divalent hydrocarbon group, a carbonyl group (—CO—), an ether bond (—O—), an ester bond (—COO—), and a carbonate group (—O—CO—O—). , An amide group (—CONH—), a group in which a plurality of these are connected, and the like.

  As said bivalent hydrocarbon group, a C1-C18 linear or branched alkylene group, a bivalent alicyclic hydrocarbon group, etc. can be mentioned, for example. Examples of the linear or branched alkylene group having 1 to 18 carbon atoms include a methylene group, a methylmethylene group, a dimethylmethylene group, an ethylene group, a propylene group, and a trimethylene group. Examples of the divalent alicyclic hydrocarbon group include 1,2-cyclopentylene group, 1,3-cyclopentylene group, cyclopentylidene group, 1,2-cyclohexylene group, 1,3-cyclopentylene group, And divalent cycloalkylene groups (including cycloalkylidene groups) such as cyclohexylene group, 1,4-cyclohexylene group, and cyclohexylidene group.

Representative examples of the compound represented by the above formula (I) include compounds represented by the following formulas (I-1) to (I-10). In the following formulas (I-5) and (I-7), n ¹ and n ² each represent an integer of 1 to 30. L in the following formula (I-5) is an alkylene group having 1 to 8 carbon atoms, such as methylene, ethylene, propylene, isopropylene, butylene, isobutylene, s-butylene, pentylene, hexylene, heptylene, octylene group, etc. And a linear or branched alkylene group. Among these, a C1-C3 linear or branched alkylene group such as methylene, ethylene, propylene, and isopropylene group is preferable. N ^{3 to} n ⁸ in the following formulas (I-9) and (I-10) are the same or different and represent an integer of 1 to 30.

  (I) As a compound having an alicyclic epoxy group, among others, from the viewpoints of curability of the curable composition, moisture resistance of the cured product, heat resistance (glass transition temperature), low shrinkage, and low linear expansion. (3,4,3 ′, 4′-diepoxy) bicyclohexyl, 3,4-epoxycyclohexylmethyl (3,4-epoxy) cyclohexanecarboxylate, bis (3,4-epoxycyclohexylmethyl) ether, and 2,2 It is preferable that at least one selected from bis (3,4-epoxycyclohexyl) propane is an essential component.

  (Ii) Examples of the compound in which the epoxy group is directly bonded to the alicyclic ring with a single bond include compounds represented by the following formula (II).

In formula (II), R ′ is a group (residue) obtained by removing p —OH from a p-valent alcohol, and p and n each represent a natural number. Examples of the p-valent alcohol [R ′-(OH) _p ] include polyhydric alcohols (preferably polyhydric alcohols having 1 to 15 carbon atoms) such as 2,2-bis (hydroxymethyl) -1-butanol. Can be mentioned. p is preferably 1 to 6, and n is preferably 1 to 30. When p is 2 or more, n in each () (in parentheses) may be the same or different. Specific examples of the compound include a 1,2-epoxy-4- (2-oxiranyl) cyclohexane adduct of 2,2-bis (hydroxymethyl) -1-butanol.

  (Iii) Examples of the hydrogenated glycidyl ether-based epoxy compound include 2,2-bis [4- (2,3-epoxypropoxy) cyclohexyl] propane and 2,2-bis [3,5-dimethyl-4. A compound obtained by hydrogenating a bisphenol A type epoxy compound such as (2,3-epoxypropoxy) cyclohexyl] propane (hydrogenated bisphenol A type epoxy compound); bis [o, o- (2,3-epoxypropoxy) Cyclohexyl] methane, bis [o, p- (2,3-epoxypropoxy) cyclohexyl] methane, bis [p, p- (2,3-epoxypropoxy) cyclohexyl] methane, bis [3 A compound obtained by hydrogenating a bisphenol F-type epoxy compound such as 5-dimethyl-4- (2,3-epoxypropoxy) cyclohexyl] methane ( Hydrogenated biphenol type epoxy compound; hydrogenated phenol novolac type epoxy compound; hydrogenated cresol novolac type epoxy compound; hydrogenated cresol novolac type epoxy compound of bisphenol A; hydrogenated naphthalene type epoxy compound; A hydrogenated product of a trisphenol methane type epoxy compound can be exemplified.

  The curable compound (B) of the present invention may contain another cationic curable compound together with the epoxy compound, for example, a compound having one or more (especially two) allyl ether groups in one molecule. (Hereinafter, sometimes referred to as “allyl ether compound”).

  Examples of the allyl ether compound include 2,2-bis (4-allyloxyphenyl) propane and cyclohexane divinyl ether. For example, commercially available products such as trade name “BPA-AE” (manufactured by Konishi Chemical Industry Co., Ltd.) can be used.

  A sclerosing | hardenable compound can be used individually by 1 type or in combination of 2 or more types. The content (blending amount) of the curable compound in the total amount (100% by weight) of the curable composition of the present invention is, for example, about 1 to 99% by weight, preferably 10 to 99% by weight, particularly preferably 15 to 99% by weight. It is. When content of a sclerosing | hardenable compound is less than the said range, depending on a use, the mechanical strength etc. of the hardened | cured material obtained may become inadequate. On the other hand, if the content of the curable compound exceeds the above range, the conductivity of the obtained cured product may be insufficient depending on the application.

  As the curable compound of the present invention, it is preferable to use (i) a compound having an alicyclic epoxy group, in that a cured product excellent in transparency, toughness, and heat resistance can be obtained. In particular, it is preferable to use (i) a compound having an alicyclic epoxy group (in particular, a compound represented by the formula (I)) and a glycidyl ether epoxy compound.

In the total curable compound (100% by weight) contained in the curable composition, the content of the compound (i) having an alicyclic epoxy group is, for example, about 40 to 90% by weight, preferably 50 to 90% by weight. It is. In the total curable compound (100% by weight) contained in the curable composition, the content of the aromatic glycidyl ether-based epoxy compound is, for example, about 10 to 60% by weight, preferably 10 to 50% by weight. is there.

  Further, when the curable composition of the present invention contains the allyl ether compound, for example, about 10 to 50% by weight, preferably 20 to 40% by weight, of the total curable compound (100% by weight), an appropriate curing delay is achieved. It is preferable at the point which can acquire the effect of.

[Other ingredients]
The curable composition of the present invention may contain other components in addition to the conductive fiber-coated particles (A) and the curable compound (B). Other components include, for example, photocationic polymerization initiators, curing retarders, conductive materials other than conductive fiber-coated particles (A), fillers (organic fillers, inorganic fillers), polymerization inhibitors, silane coupling agents. , Antioxidants, light stabilizers, plasticizers, leveling agents, antifoaming agents, organic solvents, ultraviolet absorbers, ion adsorbers, pigments, phosphors, mold release agents, surfactants, flame retardants, etc. it can. The content of other components in the total amount of the curable composition of the present invention is, for example, 30% by weight or less, preferably 20% by weight or less, particularly preferably 10% by weight or less.

(Photocationic polymerization initiator)
The cationic photopolymerization initiator is a cationic photopolymerization initiator that generates a cationic species by light irradiation and initiates a curing reaction of the cationically curable compound. The cationic photopolymerization initiator is composed of a cation moiety that absorbs light and an anion moiety that is a source of acid generation.

  Examples of the photocationic polymerization initiator of the present invention include diazonium salt compounds, iodonium salt compounds, sulfonium salt compounds, phosphonium salt compounds, selenium salt compounds, oxonium salt compounds, ammonium salt compounds, bromine salts. And the like, and the like.

  Among these, the use of a sulfonium salt compound is preferable in that a cured product having excellent curability can be formed. Examples of the cation moiety of the sulfonium salt compound include (4-hydroxyphenyl) methylbenzylsulfonium ion, triphenylsulfonium ion, diphenyl [4- (phenylthio) phenyl] sulfonium ion, and tri-p-tolylsulfonium ion. Arylsulfonium ions (which may include

Examples of the anion part of the cationic photopolymerization initiator include BF ₄ ⁻ , B (C ₆ F ₅ ) ₄ ⁻ , PF ₆ ⁻ , [(Rf) _n PF _6−n ] ⁻ (Rf: 80% of hydrogen atoms) The above is an alkyl group substituted with a fluorine atom, n: an integer of 1 to 5, AsF ₆ ⁻ , SbF ₆ ⁻ , pentafluorohydroxyantimonate, and the like.

  Examples of the photocationic polymerization initiator of the present invention include (4-hydroxyphenyl) methylbenzylsulfonium tetrakis (pentafluorophenyl) borate, 4- (4-biphenylthio) phenyl-4-biphenylphenylsulfonium tetrakis (pentafluorophenyl). ) Borate, diphenyl [4- (phenylthio) phenyl] sulfonium tetrakis (pentafluorophenyl) borate, diphenyl [4- (phenylthio) phenyl] sulfonium hexafluorophosphate, 4- (4-biphenylthio) phenyl-4-biphenylphenyl Sulfonium tris (pentafluoroethyl) trifluorophosphate, trade names “Syracure UVI-6970”, “Syracure UVI-6974”, “Syracure UVI” 6990 ”,“ Syracure UVI-950 ”(manufactured by Union Carbide, USA),“ Irgacure 250 ”,“ Irgacure 261 ”,“ Irgacure 264 ”(above, Ciba Specialty Chemicals),“ SP-150 ” “SP-151”, “SP-170”, “Optomer SP-171” (manufactured by ADEKA), “CG-24-61” (manufactured by Ciba Specialty Chemicals), “DAICAT II” (Manufactured by Daicel Corporation), "UVAC1590", "UVAC1591" (manufactured by Daicel-Cytec Co., Ltd.), "CI-2064", "CI-2639", "CI-2624", "CI-2481" , "CI-2734", "CI-2855", "CI-2823", "CI-2758", "CIT-1 82 "(manufactured by Nippon Soda Co., Ltd.)," PI-2074 "(manufactured by Rhodia, pentafluorophenyl borate toluylcumyl iodonium salt)," FFC509 "(manufactured by 3M)," BBI-102 "," “BBI-101”, “BBI-103”, “MPI-103”, “TPS-103”, “MDS-103”, “DTS-103”, “NAT-103”, “NDS-103” Chemical Co., Ltd.), "CD-1010", "CD-1011", "CD-1012" (manufactured by Sartomer, USA), "CPI-100P", "CPI-101A" (San Apro Co., Ltd.) Commercial products such as manufactured) can be used. These can be used alone or in combination of two or more.

  The used amount (blending amount) of the cationic photopolymerization initiator is, for example, 0.5 to 4 with respect to 100 parts by weight of the curable compound contained in the curable composition of the present invention (the total amount when containing two or more kinds). About parts by weight, preferably 0.2 to 2 parts by weight.

(Curing retarder)
Examples of the curing retarder include azole compounds such as pyrrole, pyrazole, 3,5-dimethylpyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole; ethylene glycol, propylene glycol, polyethylene glycol And (poly) alkylene glycols such as polypropylene glycol and butylene glycol, polyol compounds such as glycerin, polyglycerin, pentaerythritol, polycaprolactone polyol, and crown ether (particularly, aliphatic polyol compounds). These can be used alone or in combination of two or more. By adding the curing retarder, the pot life and curing start time after irradiating the curable composition of the present invention with light can be controlled. More specifically, the curing retarder can trap the cations generated from the photocationic polymerization initiator by UV irradiation to suppress the cationic polymerization of the curable compound, and release the cations when heat-treated. And has the effect of advancing cationic polymerization of the curable compound. Among the curing retardants, azole compounds are preferable in that they do not cause outgassing, and by adding to the curable composition, the pot life of the curable composition can be freely controlled, and the curable By irradiating the coating film of the composition with UV, and then applying the heat treatment to the organic EL element, the organic EL element can be sealed without being directly exposed to UV, and low outgassing and moisture resistance The organic EL element can be sealed with a cured product having the above.

  The used amount (blending amount) of the curing retarder is, for example, about 5 to 25% by weight, preferably 10 to 25% by weight, based on the used amount of the cationic photopolymerization initiator (the total amount when containing two or more kinds). .

(Conductive material other than conductive fiber-coated particles (A))
As the conductive material other than the conductive fiber-coated particles (A) (hereinafter sometimes referred to as “other conductive material”), a known or commonly used conductive substance can be used, and is not particularly limited. For example, you may use the above-mentioned conductive fiber.

  The content (blending amount) of other conductive materials (for example, conductive fibers) in the curable composition of the present invention is, for example, about 0 to 10 parts by weight, preferably about 100 parts by weight of the conductive fiber-coated particles. Is 0 to 5 parts by weight, particularly preferably 0 to 1 part by weight.

[Curable composition]
The curable composition of the present invention comprises the conductive fiber-coated particles (A) (or a dispersion of conductive fiber-coated particles (A)), a curable compound (B), and other components as necessary. For example, it can be produced by mixing uniformly using a generally known mixing apparatus such as a revolving and stirring deaerator, a homogenizer, a planetary mixer, a three roll mill, a bead mill, an ultrasonic wave, For example,
(1) A dispersion of conductive fiber-coated particles (A) obtained by mixing a particulate substance and a fibrous conductive substance in a solvent, a curable compound (B), and other components as required And stirring and mixing at a predetermined ratio, and then distilling off the solvent,
(2) By stirring and mixing the conductive fiber-coated particles (A) obtained through the following step A and step B, the curable compound (B), and other components as necessary, at a predetermined ratio. The manufacturing method etc. can be mentioned.
Step A: Step of obtaining a conductive fiber-coated particle dispersion by mixing particulate matter and fibrous conductive material in a solvent Step B: From the conductive fiber-coated particle dispersion obtained through Step A A step of obtaining conductive fiber-coated particles as a solid by removing the solvent (for example, distillation by heating and / or filtration under reduced pressure).

  The curable composition of the present invention comprises the conductive fiber-coated particles (A) (or a dispersion of conductive fiber-coated particles), the curable compound (B), and all other components used as necessary. It may be mixed in advance (one-component type), and the conductive fiber-coated particles (A), the curable compound (B), and a part of other components used as necessary may be separately stored [multi-component type (For example, two-component type)] may be mixed at a predetermined ratio immediately before use.

  Since the curable composition of this invention has the said structure, the cured | curing material excellent in transparency and electroconductivity (especially electroconductivity to the thickness direction) can be formed in low cost. When the curable composition of the present invention contains conductive fiber-coated particles in which the flexible particulate material is coated with a fibrous conductive material, the organic EL element having fine irregularities is sealed. Even when used as a material, the conductive fiber-coated particles follow the uneven structure and deform to the details, so that it can be sealed while preventing the occurrence of parts with poor conductivity, An organic EL device having excellent conductive performance can be formed.

  When the curable composition of the present invention contains a cationic curable compound as the curable compound (B) and contains a cationic photopolymerization initiator, it is quickly cured by light irradiation to form a cured product. be able to. In particular, when the curable composition of the present invention contains the above-mentioned curing retarder in addition to the cationic curable compound and the cationic photopolymerization initiator, a cured product can be formed by performing a heat treatment after light irradiation. it can.

In the case of a coating film having a thickness of 100 μm, the light irradiation is preferably performed by irradiating light of 500 mJ / cm ² or more with a mercury lamp or the like. The heat treatment is performed by heating in an oven or the like, for example, at 40 to 150 ° C. (particularly preferably 60 to 120 ° C., most preferably 80 to 110 ° C.) for 10 to 200 minutes (particularly preferably 30 to 120 minutes). Is preferred.

  The cured product obtained by curing the curable composition of the present invention is excellent in transparency, and the total light transmittance in the visible light wavelength region of the cured product (thickness: 10 μm) is, for example, 90% or more, preferably 93% or more. Particularly preferably, it is 95% or more. In addition, the total light transmittance in the visible light wavelength range of hardened | cured material can be measured based on JISK7361-1. Further, the turbidity (haze) of the cured product (thickness: 10 μm) is, for example, 5% or less, preferably 2% or less. In addition, the turbidity of the hardened | cured material of this invention can be measured based on JISK7136 * JISK7361 * ASTMD1003.

  The cured product obtained by curing the curable composition of the present invention is excellent in electrical conductivity, and has an electrical resistivity (at 25 ° C. and 1 atm) of about 0.1Ω · cm to 10 MΩ · cm, preferably 0.1Ω · cm to 1 MΩ · cm, particularly preferably 0.1 Ω · cm to 0.4 MΩ · cm.

  Since the curable composition of this invention has the said structure, the cured | curing material excellent in electroconductivity (especially electroconductivity to a thickness direction) as above-mentioned with transparency can be formed in low cost.

  In particular, when the curable composition of the present invention contains a cationic curable compound as the curable compound (B) and contains a cationic photopolymerization initiator and the above-mentioned curing retarder, the cationic polymerization is initiated by applying light irradiation. Since the cation generated from the agent is trapped by the curing retarder having a cation trapping action, the progress of cationic polymerization is suppressed even after the light irradiation until the heat treatment. Then, by performing a heat treatment after the light irradiation, the cations trapped in the curing retarder are released, and the cationic polymerization of the cationic curable compound proceeds to complete the curing. That is, by adjusting the timing at which the heat treatment is performed after light irradiation, the curing start time can be adjusted, and curing can proceed at a desired timing. Therefore, the curable composition of the present invention can be suitably used as a conductive sealant for sealing an organic EL element (particularly, a top emission type organic EL element).

  Then, by irradiating the curable composition of the present invention with light and then bonding to the organic EL element, it becomes difficult to bond the organic EL element to the UV without exposing the organic EL element to UV. The organic EL element can be sealed without causing a case.

  In more detail, by sealing an organic EL element (especially a top emission type organic EL element) through the following method 1 or 2, it is possible to achieve transparency and conductivity while preventing deterioration of the element due to light irradiation. The organic EL element can be sealed with an excellent cured product, and a long-life and highly reliable organic EL device can be provided. In addition, light irradiation and the heat processing method can be performed by the method as described above.

<Method 1: See FIG. 2>
Step 1-1: Applying the curable composition of the present invention on a lid to form a coating film / lid laminate Step 1-2: Applying light to the coating step 2-1: Organic EL on the substrate The element is installed, and the coating film / lid laminate after light irradiation is bonded to the organic EL element installation surface so that the coating film surface faces the element installation surface. Step 2-2: The coating film is applied by performing a heat treatment. Harden

<Method 2>
Step 1-1 ′: Forming the sealing sheet or film by applying the curable composition of the present invention to the surface of release paper, etc. Step 1-2 ′: Applying light to the sealing sheet or film 2-1: An organic EL element is installed on a substrate, and a sealing sheet or film after light irradiation and a lid are laminated in this order on the organic EL element installation surface side. Step 2-2: By performing heat treatment Curing the sealing sheet or film

  As the lid (lid) and the substrate, it is preferable to use a moisture-proof base material, for example, a glass substrate such as soda glass or non-alkali glass; a metal substrate such as stainless steel or aluminum; a polyethylene trifluoride or a polytrifluoride. Polyfluorinated ethylene polymers such as chlorinated ethylene chloride (PCTFE), polyvinylidene fluoride (PVDF), copolymers of PCTFE and PVDF, copolymers of PVDF and polyfluorinated ethylene chloride, polyimide, polycarbonate, dicyclopentadiene Examples thereof include cycloolefin resins such as polyethylene, polyesters such as polyethylene terephthalate, resin substrates such as polyethylene and polystyrene, and the like.

  The organic EL element includes a laminate of anode / light emitting layer / negative electrode. If necessary, a passivation film such as a SiN film may be provided.

  The coating film made of the curable composition of the present invention is formed by, for example, applying a dam material on a lid to form a dam, and using a dispenser such as a dispenser in the dam. It can be formed by discharging. The thickness of the coating film is not particularly limited as long as the purpose of protecting the organic EL element can be achieved.

  Further, when the curable composition is discharged by a dispenser such as a dispenser, it is preferable to discharge the conductive fiber-coated particles (A) in the curable composition in a highly dispersed state. It is preferable to discharge while stirring by a screw type discharge method in which a curable composition is discharged by rotation of a screw using a discharger having a rotation drive structure. The rotational speed of the screw, the size of the blade of the screw, and the like are preferably adjusted as appropriate according to the viscosity of the curable composition, the size of the conductive fiber-coated particles (A) contained therein, and the like.

  According to the above method, the organic EL element is directly exposed to UV in order to bond the coating film to the organic EL element after light irradiation to the coating film made of the curable composition of the present invention. Therefore, it is possible to prevent the deterioration of the organic EL element due to UV. In addition, the curable composition of the present invention can form a cured product having both transparency and conductivity. Therefore, if the curable composition of the present invention is used as a sealing material for an organic EL device, it can be protected without lowering the light extraction efficiency, and the electrodes can be reliably conductively connected.

  And the organic EL device (for example, a display, illumination, etc.) obtained by the said method does not have deterioration caused by being exposed to UV at the time of sealing, but is a cured product having both transparency and conductivity. Since it is protected, it has excellent light extraction efficiency and high brightness.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. The refractive index was measured using a trade name “MODEL 2010 / M prism coupler” (manufactured by Metricon) at 25 ° C. and a wavelength of 589.3 nm (sodium D-line).

Example 1
0.85 parts by weight of plastic fine particles (a-1) were mixed in 29.15 parts by weight of ethanol and dispersed to prepare a dispersion of plastic fine particles (a-1). And the dispersion liquid of the obtained plastic fine particles (a-1) and the dispersion liquid of silver nanowires 5.22 parts by weight (silver nanowire content: 0.15 parts by weight) are mixed to prepare the mixture liquid (1). Prepared.

The solvent was removed by stirring the mixed liquid (1) while heating at 70 ° C. for 30 minutes to obtain conductive fiber-coated particles (1).
Incidentally, the plastic particles (a-3) the surface area per one is 312.7Myuemu ^2, the projected area per one silver nanowires is 2.4 [mu] m ^2. From the plastic fine particles (a-3) and silver nanowires prepared above, it is considered that 25 silver nanowires are adsorbed to one plastic fine particle (a-3). Surface area) / projection area of silver nanowire (total projection area) is about 100/5.
The obtained conductive fiber-coated particles (1) were observed with a scanning electron microscope (SEM) (magnification: 100,000). As a result, it was confirmed that the silver nanowires were adsorbed on the surface of the plastic fine particles (the surface of the plastic fine particles was covered with the silver nanowires) (see FIG. 1).

  The binder resin (1) was prepared by mixing 43 parts by weight of the curable compound (b-1), 57 parts by weight of the curable compound (b-2), 2 parts by weight of the cationic polymerization initiator, and 0.4 parts by weight of the curing retarder. Got. In addition, the refractive index of the hardened | cured material obtained by hardening | curing the obtained binder resin by the method similar to the following was 1.5635.

  The obtained conductive fiber-coated particles (1) and the binder resin (1) were mixed to obtain a curable composition (1).

  About the obtained curable composition (1), 2 mL is sampled into a test tube (test tube size: tube diameter: 1 cm × height: 2.5 cm), and left to stand in an environment of 25 ° C. and 1 atm. Dispersibility was evaluated by measuring the time until the conductive fiber-coated particles (1) completely settled. The time point (end point) when the conductive fiber-coated particles (1) completely settled is the time point when it was possible to visually confirm that the binder resin became transparent.

Further, the obtained curable composition (1) was sandwiched between two conductive glass substrates (Luminescence Technology, size: 25 mm × 25 mm, ITO thickness: 0.14 μm) (film thickness: 10 μm) Then, ultraviolet rays were irradiated with a mercury lamp (irradiation amount: 1600 mJ / cm ² ). Then, it heated at 100 degreeC for 1 hour, and obtained the conductive glass substrate / cured material (1) / conductive glass substrate laminated body.

  About the obtained conductive glass substrate / cured product (1) / conductive glass substrate laminate, voltage (V) using an electron meter (manufactured by PSS Co., Ltd.) under an environment of 25 ° C. and 1 atm. The electrical resistivity (Ω · cm) was obtained and the conductivity was evaluated.

Furthermore, the total light transmittance at 450 nm of the cured product (1) (film thickness: 10 μm) was measured using a spectrophotometer (trade name “U-3900H”, manufactured by Hitachi, Ltd.).
Furthermore, the haze (turbidity) of the cured product (1) was measured using a turbidimeter (trade name “Haze Meter NDH 300A”, manufactured by Nippon Denshoku Industries Co., Ltd.).

Example 2, Comparative Examples 1-3
The same procedure as in Example 1 was performed except that the composition shown in Table 1 was changed.

The compounds used in Examples and Comparative Examples are as follows.
<Conductive fine particles>
Particulate matter
a-1: Fine particles made of acrylic resin, trade name “L-11R”, manufactured by Hayakawa Rubber Co., Ltd., refractive index: 1.49, average particle size: 10.0 μm, CV value: 4.5, 10% Compressive strength: 5 kgf / mm ²
a-2: Fine particles comprising methyl methacrylate-styrene copolymer, trade name “SM10X-8JH”, manufactured by Sekisui Plastics Co., Ltd., refractive index: 1.565, average particle size: 8.3 μm, CV value : 39, 10% compressive strength: 2.4 to 2.5 kgf / mm ²
a-3: Fine particles comprising a crosslinked polyacrylic acid ester, trade name “AFX-8”, manufactured by Sekisui Plastics Co., Ltd., refractive index: 1.49, average particle size: 8 μm, CV value: 30, 10% Compressive strength: 0.5 kgf / mm ²
Silver nanowire: average thickness: 115 nm, length: 20-50 μm, manufactured by Aldrich Micropearl AU: the surface of a particulate material composed of a cross-linked polymer containing divinylbenzene as a main component, the product name “Micro Pearl AU-2085 ", manufactured by Sekisui Chemical Co., Ltd., average particle size: 8.5 μm
<Binder resin>
Curable compound
b-1: Bisphenol F diglycidyl ether, trade name “YL-983U”, manufactured by Mitsubishi Chemical Corporation
b-2: (3,4,3 ′, 4′-diepoxy) bicyclohexyl
b-3: 3,4-epoxycyclohexylmethyl (3,4-epoxy) cyclohexanecarboxylate, trade name “Celoxide 2021P”, manufactured by Daicel Corporation
b-4: 1,6-hexanediol diglycidyl ether,
Cationic polymerization initiator: Photocationic polymerization initiator, 4- (4-biphenylthio) phenyl-4-biphenylphenylsulfonium tetrakis (pentafluorophenyl) borate Curing retarder: Dimethylpyrazole, trade name “Chemcat P-9600”, Made by Otsuka Chemical Co., Ltd.

1 Lid 2 Dam 3 Dispenser 4 Curable composition 5 Substrate 6 Cathode 7 Light emitting layer 8 Anode

Claims (15)

  A curable composition comprising conductive fiber-coated particles (A) and a curable compound (B) containing a particulate material and a fibrous conductive material that coats the particulate material, the conductive fiber The coefficient of variation (CV value) of the particulate matter constituting the coated particles (A) is 25 or less, and the total light transmittance [converted to a thickness of 10 μm] in the visible light wavelength region of the cured product of the curable composition is 90%. The curable composition characterized by the above.   The curable composition according to claim 1, wherein the fibrous conductive material constituting the conductive fiber-coated particles (A) is a conductive nanowire.   The curable composition according to claim 2, wherein the conductive nanowire is at least one selected from the group consisting of metal nanowires, semiconductor nanowires, carbon fibers, carbon nanotubes, and conductive polymer nanowires.   The curable composition according to claim 2, wherein the conductive nanowire is a silver nanowire.   The curing according to any one of claims 1 to 4, wherein the fibrous conductive material constituting the conductive fiber-coated particles (A) has an average diameter of 1 to 400 nm and an average length of 1 to 100 µm. Sex composition.   The curable composition according to any one of claims 1 to 5, wherein an average particle diameter of the particulate material constituting the conductive fiber-coated particles (A) is 0.1 to 100 µm.   The curable composition according to any one of claims 1 to 6, wherein the content of the fibrous conductive material is 0.01 to 1.0 part by weight with respect to 100 parts by weight of the curable compound (B). object.   The curable composition according to any one of claims 1 to 7, wherein the curable compound (B) contains a compound having at least an alicyclic structure and an epoxy group in one molecule. The curable composition according to any one of claims 1 to 8, wherein the curable compound (B) includes at least a compound represented by the following formula (I).
(In the formula, R ^{1 to} R ¹⁸ are the same or different and each represents a hydrogen atom, a halogen atom, an oxygen atom, a hydrocarbon group that may contain a halogen atom, or an alkoxy group that may have a substituent. , X represents a single bond or a connecting group)   The electroconductive sealing agent for organic electroluminescent element sealing containing the curable composition of any one of Claims 1-9.   The electroconductive sealing agent for top emission type organic electroluminescent element sealing containing the curable composition of any one of Claims 1-9.   Hardened | cured material obtained by hardening the curable composition of any one of Claims 1-9.   The hardened | cured material of Claim 12 whose total light transmittance [thickness 10micrometer conversion] in a visible light wavelength range is 90% or more.   The hardened | cured material of Claim 12 or 13 whose electrical resistivity (at 25 degreeC and 1 atmosphere) is 0.1 ohm * cm-10Mohm * cm.   The organic electroluminescent device by which an organic electroluminescent element is sealed with the hardened | cured material of any one of Claims 12-14.