TWI640595B - Film-like adhesive containing particles coated with conductive fibers and use thereof - Google Patents

Abstract

The present invention provides a film-like adhesive which can encapsulate a semiconductor element by being easily bonded to a semiconductor element and can encapsulate a semiconductor element with a cured product excellent in transparency and conductivity (particularly, conductivity in a thickness direction). And a semiconductor device in which a semiconductor element is encapsulated by a cured product of the film-like adhesive.

The film-form adhesive of the present invention is characterized by comprising particles (A) coated with conductive fibers and resin (B), the particles (A) of the coated conductive fibers containing a particulate matter and covering the particulate matter Fibrous conductive material. The fibrous conductive material constituting the particles (A) covering the conductive fibers is preferably a conductive nanowire, and particularly preferably a silver nanowire.

Description

Film-like adhesive containing particles coated with conductive fibers and use thereof

The present invention relates to a film-form adhesive comprising particles of a coated conductive fiber composed of a particulate material and a fibrous conductive material. The film-like adhesive is useful as a sheet-shaped package of a semiconductor element such as an organic EL element. Priority is claimed on Japanese Patent Application No. 2014-010771, filed on Jan.

The organic electroluminescence (hereinafter 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 of the electrodes, and the other is injected from the other side. The electrode is injected into the hole. Light is generated when the injected electrons and holes are recombined in the light-emitting layer. The organic EL device including the organic EL element is expected to be a full-color flat panel display or a substitute for an LED in view of high punching resistance, high visibility, and illuminating color. In the light extraction method of the organic EL device, there are two types of top emission type and bottom emission type, and the top emission type is excellent in the light extraction efficiency because of the large aperture ratio.

However, the organic EL element is more susceptible to moisture than other electronic components, and causes oxidation of the electrode or modification of an organic substance due to moisture permeating into the organic EL element, and thus the light-emitting property is remarkably lowered. Department of affairs. As a method for solving this problem, a method of encapsulating an organic EL element around a package material having moisture resistance is known. In particular, when it is a top emission type, since the package is disposed in the light extraction direction, it is required to be packaged with a moisture barrier and transparency.

In the method of encapsulating the periphery of the organic EL element with a moisture-proof sealing material, it is known that a dam is provided around the organic EL element, and the inside of the dam is filled with a liquid package and hardened. A method of bonding a sheet-shaped package material to an organic EL element and hardening it. The latter is preferable in that the packaging operation can be easily performed and the contamination of the substrate due to the outflow of the sealing material can be prevented as in the case of using the liquid packaging material.

Then, according to the package material having moisture resistance, transparency, and conductivity, the organic EL element can be protected without damaging the light extraction efficiency, and the electrodes can be reliably electrically connected to each other. In the method of imparting conductivity to a sealing material, it is known that a conductive fine particle obtained by coating a metal on the surface of a fine particle made of a resin is bonded to an insulating curable compound (for example, a thermosetting compound). The method of hardening (refer to Patent Documents 1 to 4).

However, since the above-mentioned conductive fine particles are coated with the entire surface of the resin-made fine particles, many expensive metal materials are used, which has a problem that the raw material cost is high. Further, since it is necessary to manufacture by a special method such as electrolytic plating or cross-adsorption, it is necessary to use a special device or a large number of steps, and it also has a problem of high manufacturing cost.

Further, the conductive fine particles are colored by coating the entire surface with a metal coating layer, and in order to impart conductivity to the sealing material, it is necessary to cause the conductive fine particles to contact each other in the sealing material. As a result of blending, it is difficult to obtain a cured product having both transparency and conductivity.

A method of applying a conductive ink to a surface of a package material or a method of forming a metal wiring or the like in consideration of a method of maintaining conductivity while maintaining transparency of a package material. According to this method, although the transparency of the sealing material can be ensured while imparting conductivity, the surface of the sealing material can be imparted with conductivity in the surface direction, and the conductivity cannot be expressed in the thickness direction of the sealing material.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 3241276

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2000-251536

[Patent Document 3] Japanese Laid-Open Patent Publication No. 62-188184

[Patent Document 4] Japanese Patent Laid-Open No. Hei 10-226773

Accordingly, an object of the present invention is to provide a film-like adhesive which can be easily encapsulated by bonding to a semiconductor element and hardened, and which can be transparent and electrically conductive (especially, in the thickness direction) Electrical conductivity) Excellent hardened material to encapsulate semiconductor components.

Another object of the present invention is to provide a semiconductor device The semiconductor element is encapsulated by a cured product of the film-like adhesive.

The inventors of the present invention conducted in-depth discussions to solve the above problems and found the following items:

1. The particles of the coated conductive fiber can be obtained simply and inexpensively by mixing the particulate material and the fibrous conductive material

2. Since the cured product contains a small amount of the particles coated with the conductive fibers, the cured film containing the film-like adhesive can have excellent conductivity without impairing its transparency (especially Conductivity in the thickness direction) and can suppress the rise in raw material costs

3. When the particles of the coated conductive fiber are added to the film-form adhesive, a film which can easily encapsulate the organic EL element with a cured product excellent in transparency and conductivity (particularly, conductivity in the thickness direction) can be obtained. Adhesive

The present invention has been accomplished based on such knowledge.

That is, the present invention provides a film-like adhesive comprising particles (A) coated with conductive fibers and a resin (B), the particles (A) of the coated conductive fibers comprising a particulate material and coating the particles A fibrous conductive substance of matter.

Further, the present invention provides a film-like adhesive agent as described above, wherein the fibrous conductive material-based conductive nanowire constituting the particles (A) coated with the conductive fibers.

The present invention further provides a film-like adhesive agent as described above, wherein the conductive nanowire is selected from the group consisting of a metal nanowire, a semiconductor nanowire, a carbon fiber, a carbon nanotube, and a conductive polymer nanowire. Group At least one.

The present invention further provides a film-like adhesive agent as described above, wherein the conductive nanowire is a silver nanowire.

The present invention further provides a film-like adhesive agent as described above, wherein the content of the particles (A) coated with the conductive fibers is 0.01 to 10% by weight based on the total amount of the film-like adhesive.

Further, the present invention provides the film-form adhesive according to the above aspect, wherein the particulate matter constituting the particulate material (A) coated with the conductive fibers has a median diameter of 70 to 100% of the thickness of the film-like adhesive.

The present invention further provides a film-like adhesive as described above, which is used for packaging of a semiconductor element.

The present invention further provides a sheet for encapsulation which is obtained by laminating a film-form substrate in the form of a film-like adhesive as described above.

The present invention further provides a cured product obtained by hardening a film-like adhesive as described above.

The present invention further provides a cured product as described above, which has a total light transmittance [in terms of thickness 10 μm] in the visible light wavelength region of 87% or more.

The present invention further provides a semiconductor device in which a semiconductor element is packaged in a cured material as described above.

That is, the present invention relates to the following.

[1] A film-like adhesive comprising particles (A) coated with a conductive fiber and a resin (B), wherein the particles (A) coated with the conductive fiber contain a particulate matter and are coated with the particulate matter Fibrous conductive material.

[2] The film-form adhesive according to [1], wherein the fibrous conductive material-based conductive nanowires constituting the particles (A) coated with the conductive fibers.

[3] The film-form adhesive according to [2], wherein the conductive nanowire is selected from the group consisting of a metal nanowire, a semiconductor nanowire, a carbon fiber, a carbon nanotube, and a conductive polymer nanowire. At least one of the groups.

[4] The film-form adhesive according to [2], wherein the conductive nanowire is a silver nanowire.

[5] The film-form adhesive according to any one of [1] to [4] wherein the content of the particles (A) coated with the conductive fibers is 0.01 to 10% by weight based on the total amount of the film-like adhesive.

[6] The film-form adhesive according to any one of [1] to [5] wherein the median diameter of the particulate matter constituting the particulate material (A) coated with the conductive fiber is 70 of the thickness of the film-like adhesive. To 100%.

[7] The film-form adhesive according to any one of [1] to [6] wherein the content of the resin (B) is 50 to 99.99% by weight based on the total amount of the film-like adhesive.

[8] The film-form adhesive according to any one of [1], wherein the resin (B) contains at least a curable compound having a cationically polymerizable group and/or a radical polymerizable group in one molecule. .

[9] The film-form adhesive according to any one of [1] to [7] wherein the resin (B) contains a cationically polymerizable group and/or a radical polymerization in one molecule which is liquid at normal temperature. A curable compound which is a base, and a curable compound which has a cationically polymerizable group and/or a radical polymerizable group in one molecule at a normal temperature.

[10] The film-form adhesive according to [8] or [9], wherein the content of the curable compound having a cationically polymerizable group and/or a radical polymerizable group in one molecule in the total amount of the resin (B) It is 20% by weight or more.

[11] The film-form adhesive according to any one of [1] to [10], wherein Further containing a polymerization initiator.

[12] The film-form adhesive according to [11], which contains a polymerization initiator 0.1 to 5 with respect to 100 parts by weight of a curable compound having a cationically polymerizable group and/or a radical polymerizable group in one molecule. Parts by weight.

[13] The film-form adhesive according to any one of [1] to [12], which is used for encapsulation of a semiconductor element.

[14] A sheet for encapsulation, which is obtained by laminating a film-form substrate of a film-form adhesive as described in any one of [1] to [13].

[15] A cured product obtained by curing the film-form adhesive described in any one of [1] to [13].

[16] The cured product according to [15], which has a total light transmittance [in terms of thickness 10 μm] in the visible light wavelength region of 87% or more.

[17] The cured product according to [15] or [16], wherein the electrical resistivity at 25 ° C and 1 atm is from 0.1 Ω ‧ cm to 10 M Ω ‧ cm.

[18] A semiconductor device in which a semiconductor element is encapsulated with a cured material as described in any one of [15] to [17].

The film-form adhesive of the present invention can be easily encapsulated by directly bonding to a semiconductor element and hardening without forming a dam to form a liquid package around the semiconductor element, and is excellent in workability.

In addition, the film-form adhesive of the present invention contains particles of the coated conductive fiber which can be provided with a small amount of addition and impart excellent conductivity (especially conductivity in the thickness direction). For this reason, it is possible to form both excellent transparency and excellent electrical conductivity (especially A cured product of electrical conductivity in the thickness direction.

Further, the particles of the coated conductive fibers can be produced by a simple method without using a special device, and it is not necessary to use a large amount of a highly expensive conductive material (a material having conductivity) as a raw material. Therefore, the film-form adhesive of the present invention can be provided at a low cost by suppressing an increase in the cost of raw materials.

In particular, in the case where particles of the coated conductive fiber having flexibility are contained as the particles of the coated conductive fiber, the particles of the coated conductive fiber having flexibility can be deformed and propagated in accordance with the uneven structure of the semiconductor element. In the case of the detail, it is possible to prevent the occurrence of a portion where conductivity is poor, and it is possible to obtain a cured product having excellent conductivity.

Therefore, the film-form adhesive of the present invention can be suitably used as a sheet-shaped package of a semiconductor element (for example, an organic EL element such as a top emission type organic EL element).

Furthermore, the semiconductor device (for example, an organic EL device) of the present invention encapsulated by the cured product of the film-form adhesive of the present invention has excellent light extraction efficiency (that is, excellent luminous efficiency) and high luminance.

1‧‧‧Substrate

2‧‧‧ cathode

3‧‧‧Lighting layer

4‧‧‧Anode

5‧‧‧film-like adhesive

6‧‧‧ Cover

Fig. 1 is an example of a scanning electron microscope image (SEM image) of particles coated with a conductive fiber of the present invention.

Fig. 2 is a schematic view showing an example of a method of producing an organic EL device using the film-like adhesive of the present invention.

[Formation of the Invention]

[Coated particles of conductive fibers (A)]

The particles of the coated conductive fiber of the present invention are particles of a coated conductive fiber containing a particulate material and a fibrous conductive material (sometimes referred to as "conductive fiber" in the present specification) coated with the particulate matter. Further, the term "coating" in the particles of the coated conductive fiber of the present invention means that the conductive fiber covers a part or all of the surface of the particulate material. In the particles of the coated conductive fiber of the present invention, the conductive fibers may be coated on at least a part of the surface of the particulate material. For example, the uncoated portion may have more than the coated portion. Further, in the particles of the coated conductive fiber of the present invention, the particulate material and the conductive fiber do not necessarily need to be in contact with each other, but usually a part of the conductive fiber is in contact with the surface of the particulate material.

Fig. 1 is an example of a scanning electron microscope image of particles coated with a conductive fiber of the present invention. As shown in Fig. 1, the particles of the coated conductive fiber of the present invention have at least a part of a particulate material (a material having a true spherical shape in Fig. 1) covered with a conductive fiber (a fibrous material in Fig. 1). Composition.

(particulate matter)

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

The material (material) constituting the particulate matter is not particularly limited, and examples thereof include known or customary materials such as metal, plastic, rubber, ceramic, glass, and cerium oxide. In the present invention, it is preferred to use a transparent material such as transparent plastic, glass, or cerium oxide. The special system uses transparent plastic.

The transparent plastic contains a thermosetting resin, a thermoplastic resin, or the like. The thermosetting resin may, for example, be a poly(meth)acrylate resin; a polystyrene resin; a polycarbonate resin; a polyester resin; a polyurethane resin; an epoxy resin; a polyfluorene resin; Amorphous polyolefin resin; divinylbenzene, hexatriene, divinyl ether, divinyl fluorene, diallyl methanol, alkylene diacrylate, oligomeric or polyalkylene glycol Polyalkylene glycol diacrylate, oligomeric or polyalkylene glycol dimethacrylate, alkylene triacrylate, alkylene tetraacrylate, alkyl trimethacrylate, alkyl tetramethyl Polyfunctional monomers such as acrylate, alkyl bis decyl decylamine, alkyl bis methacrylamide, and terminal propylene fluorenyl modified polybutadiene oligomer, alone or in combination with other monomers The obtained mesh polymer; phenol formaldehyde resin, melamine formaldehyde resin, benzoguanidine formaldehyde resin, urea formaldehyde resin and the like. Examples of the thermoplastic resin include an ethylene/vinyl acetate copolymer, an ethylene/vinyl acetate/unsaturated carboxylic acid copolymer, an ethylene/ethyl acrylate copolymer, an ethylene/methyl methacrylate copolymer, and ethylene/ Acrylic copolymer, ethylene/methacrylic acid copolymer, ethylene/maleic anhydride copolymer, ethylene/amino methacrylate copolymer, ethylene/vinyl decane copolymer, ethylene/glycidyl methacrylate copolymerization , ethylene/hydroxyethyl methacrylate copolymer, methyl (meth)acrylate/styrene copolymer, acrylonitrile/styrene copolymer, and the like.

The shape of the particulate material is not particularly limited, and examples thereof include a spherical shape (a true spherical shape, a substantially true spherical shape, an elliptical spherical shape, etc.), and a plurality of Surface shape, rod shape (cylindrical shape, angular column shape, etc.), flat shape, scale shape, indefinite shape, and the like. In the present invention, it is preferable that the particles of the coated conductive fiber can be produced with high productivity, and the resin (B) can be easily dispersed uniformly and the conductive material can be easily imparted to the entire cured product. Spherical, rod-shaped, especially spherical (especially true spherical).

The average aspect ratio of the particulate matter is not particularly limited, but is preferably less than 20 (for example, 1 or more and less than 20), and particularly preferably 1 to 10. When the average aspect ratio is outside the above range, when the particles of the conductive fibers are blended in a small amount, it is difficult to make the resin (B) excellent in conductivity. Further, the average aspect ratio of the particulate matter can be determined by, for example, using an electron microscope (SEM, TEM) for a sufficient number (for example, 100 or more, preferably 300 or more; particularly 100, 300) particles. The object is subjected to a scanning electron microscope image, and the aspect ratio of the particulate matter is measured and averaged.

Further, the configuration of the particulate material is not particularly limited, and may be a single layer structure or a multilayer (multilayer) structure. Further, the particulate matter may be any of solid particles, hollow particles, and porous particles.

The average particle diameter of the particulate material is 70 to 100% (80 to 100%) of the thickness of the film-like adhesive of the present invention, and is capable of imparting excellent electrical conductivity (especially conductivity in the thickness direction). The above is preferred, for example, preferably from 0.1 to 100 μm, particularly preferably from 1 to 50 μm, and most preferably from 5 to 30 μm. Since the average particle diameter is less than the above range, the thickness of the film-form adhesive obtained can be thinned, and the encapsulation performance is lowered. On the other hand, if the average particle diameter is outside the above range, the thickness of the obtained film-form adhesive becomes large, and the transparency is lowered. become In the case where the particulate matter is an anisotropic shape, the average particle diameter in the long axis (longest axis) direction is preferably controlled within the above range. Furthermore, the average particle size of the above particulate matter is based on laser diffraction. The median particle size (D50) of the scattering method.

The above particulate matter is preferably transparent. Specifically, the total light transmittance of the particulate material in the visible light wavelength region is not particularly limited, but is preferably 70% or more, and particularly preferably 75% or more. If the total light transmittance is less than the above range, the transparency of the film-like adhesive or the cured product thereof may be lowered. Further, the total light transmittance of the particulate matter in the visible light wavelength region is in the state of the particulate material-based plastic particles by using a monomer which is a raw material of the particulate matter between 80 and 150 in the glass. The plate was polymerized in a temperature range of °C to obtain a flat plate having a thickness of 1 mm, and the total light transmittance of the flat plate in the visible light wavelength region was determined in accordance with JIS K7361-1.

Further, the particulate material preferably has flexibility, and 10% compressive strength is, for example, 10 kgf/mm ² or less, preferably 5 kgf/mm ² or less, and particularly preferably 3 kgf/mm ² or less. The particles of the coated conductive fibers containing the particulate matter having a compressive strength of 10% in the above range are deformed by following the fine uneven structure by pressurization. Therefore, when the film-form adhesive containing the particles of the coated conductive fiber is used for the package of the organic EL element having the fine uneven structure, the particles of the coated conductive fiber can be spread over the fine portion and the conductive can be prevented. The production becomes a defective part, and a cured product excellent in conductivity is obtained.

The refractive index of the above particulate matter is not particularly limited, and is preferably from 1.4 to 2.7, particularly preferably from 1.5 to 1.8. Furthermore, the above particulate matter In the case where the particulate material is a plastic particle, the monomer which is a raw material of the particulate material can be polymerized in a temperature range of 80 to 150 ° C to prepare a test piece having a length of 20 mm × a width of 6 mm. Using a multi-wavelength Abbe refractometer (trade name "DR-M2", manufactured by ATAGO) in the state where the ruthenium naphthalene was used as an intermediate liquid and the ruthenium was adhered to the test piece, 25 ° C, sodium D was measured. The refractive index of the line is obtained.

Moreover, it is preferable that the particulate matter is small in refractive index difference from the resin (B) or a cured product described later, and the refractive index of the particulate matter of the particles (A) covering the conductive fibers and the cured product of the resin (B). The absolute value of the rate difference (at 25 ° C and a wavelength of 589.3 nm) is preferably 0.02 or less (preferably 0.01 or less, and particularly preferably 0.005 or less). In other words, the particles (A) and the resin (B) of the coated conductive fibers contained in the film-form adhesive of the present invention preferably satisfy the following formula.

| refractive index (at 25 ° C, wavelength 589.3 nm) of the particulate material constituting the particle (A) coated with the conductive fiber - refractive index of the cured product of the resin (B) (at 25 ° C, wavelength 589.3 nm) | ≦0.02

Further, in the point that the excellent conductivity can be imparted with a small amount of use, the particulate material has a sharp particle size distribution (= small variation in particle diameter), and a coefficient of variation (CV value) is preferable. It is preferably 40 or less (excellently 30 or less, and preferably 10 or less).

Further, the coefficient of variation of the particulate matter in the volume-based particle size distribution can be calculated by the following formula. Further, the particle size distribution can be measured using a particle size distribution measuring device (trade name "Coulter Multisizer", manufactured by Beckman Coulter, Inc.) or the like.

Coefficient of variation (CV value) (%) = (S2/Dn) × 100

(wherein, S2 shows the standard deviation in the volume-based particle size distribution, and Dn shows the median diameter (D50) in the volume basis)

The particulate matter can be produced by a known or customary method, and the production method thereof is not particularly limited. For example, in the case of a metal particle, it can be produced by a vapor phase method such as a CVD method or a spray pyrolysis method, or a wet method such as a chemical reduction reaction. Further, in the case of a plastic particle, for example, a monomer constituting the resin (polymer) exemplified above can be subjected to a suspension polymerization method, an emulsion polymerization method, a seed polymerization method, a dispersion polymerization method, or the like. It is produced by a known polymerization method, a method of polymerization, or the like.

Commercially available products can also be used in the context of the present invention. Examples of the particulate material derived from the thermosetting resin include "Techpolymer MBX Series", "Techpolymer BMX Series", "Techpolymer ABX Series", "Techpolymer ARX Series", and "Techpolymer AFX Series" (above). , the product name "Micropearl SP", "Micropearl SI" (above, Sekisui Chemical Industry Co., Ltd.); as a particulate material made of a thermoplastic resin, for example, a product "Soft beads" (Sumitomo Seiki Co., Ltd.), trade name "Duomaster" (product of Sekisui Chemicals Co., Ltd.).

(fibrous conductive material (conductive fiber))

The conductive fiber constituting the particles of the coated conductive fiber of the present invention has a conductive fibrous structure (linear structure). The shape of the conductive fiber is not particularly limited as long as it is fibrous (microfilament), and the average aspect ratio is preferably 10 or more (for example, 20 to 5000). It is 50 to 3000, preferably 100 to 1000. If the average aspect ratio is less than the above range, it may become difficult to exhibit excellent conductivity by blending a small amount of particles coated with the conductive fibers. The average aspect ratio of the above conductive fibers is determined by the same procedure as the average aspect ratio of the particulate matter. In addition, the concept of "fibrous" in the above-mentioned conductive fiber also includes the shape of various linear structures such as "filament" or "rod". Further, in the present specification, a fiber having an average thickness of 1000 nm or less may be referred to as a "nano wire".

The average thickness (average diameter) of the above conductive fibers is not particularly limited, but is preferably from 1 to 400 nm, particularly preferably from 10 to 200 nm, and most preferably from 50 to 100 nm. When the average thickness is less than the above range, the conductive fibers are likely to aggregate with each other, and the production of particles coated with the conductive fibers may be difficult. On the other hand, if the average thickness is outside the above range, it becomes difficult to coat the particulate matter, and it is difficult to efficiently obtain the particles of the coated conductive fiber. The average thickness of the above-mentioned conductive fibers can be obtained by using an electron microscope (SEM, TEM) for a sufficient number (for example, 100 or more, preferably 300 or more; particularly 100, 300) of conductive fibers. The electron microscope image was measured by measuring the thickness (diameter) of the conductive fibers and calculating the average.

The average length of the above-mentioned conductive fibers is not particularly limited, but is preferably 1 to 100 μm, particularly preferably 5 to 80 μm, and most preferably 10 to 50 μm. If the average length is less than the above range, it becomes difficult to coat the particulate matter, and it is impossible to efficiently obtain the particles of the coated conductive fiber. On the other hand, if the average length is outside the above range, conductive fibers adhere or adsorb to a plurality of particles, causing coated conductive fibers. The state of aggregation of particles (deterioration of dispersibility). The average length of the above-mentioned conductive fibers can be determined by using an electron microscope (SEM, TEM) for a sufficient number (for example, 100 or more, preferably 300 or more; particularly 100, 3 (00) conductive fibers. The length of the conductive fibers is measured and averaged to calculate the length of the conductive fibers, and the length of the conductive fibers is measured in a state in which the stretching is linear, but in reality, In many cases, the projection diameter and the projected area of the conductive fiber are calculated from the electron microscope image using a video analyzer, and one cylinder is assumed and calculated from the following equation.

Length = projected area / projected diameter

The material (material) constituting the conductive fiber may be a material having conductivity, and examples thereof include a metal, a semiconductor, a carbon material, and a conductive polymer.

Examples of the metal include known or customary metals such as gold, silver, copper, iron, nickel, cobalt, tin, and the like. In the present invention, among them, silver is preferred in terms of excellent electrical conductivity.

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

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

Examples of the conductive polymer include polyacetylene, polyacene, polyparaphenylene, polyparaphenylene vinylene, polypyrrole, polyaniline, and polythiophene. And such derivatives (for example, in the common polymer backbone having an alkyl group, a hydroxyl group, a carboxyl group, an ethylenedioxy group, etc. Base; specifically, polyethylene dioxythiophene, etc.). In the present invention, among them, polyacetylene, polyaniline and derivatives thereof, polypyrrole and derivatives thereof, polythiophene and derivatives thereof are preferred. Further, the conductive polymer may contain a known or conventional dopant (for example, a halogen, a halide, a Lewis acid or the like; a base such as an alkali metal or an alkaline earth metal).

The conductive fiber of the present invention is preferably a conductive nanowire, and is particularly preferably selected from the group consisting of a metal nanowire, a semiconductor nanowire, a carbon fiber, a carbon nanotube, and a conductive polymer nanowire. At least one type of conductive nanowire of the group is particularly preferably a silver nanowire which is excellent in electrical conductivity.

The above conductive fibers can be produced by a known or customary production method. For example, the above metal nanowire can be produced by a liquid phase method, a gas phase method, or the like. More specifically, the silver nanowire, for example, can be described by Mater. Chem. Phys. 2009, 114, p333-338, Adv. Mater. 2002, 14, p833-837 or Chem. Mater. 2002, 14. It is produced by the method of p. 4736-4745 and JP-A-2009-505358. Further, the gold nanowire can be produced, for example, by the method described in JP-A-2006-233252. Further, the copper nanowire can be produced, for example, by the method described in JP-A-2002-266007. Further, the cobalt nanowire can be produced, for example, by the method described in JP-A-2004-149871. Further, the above-described semiconductor nanowire can be produced, for example, by the method described in JP-A-2010-208925. The carbon fiber can be produced, for example, by the method described in JP-A-06-081223. The above-mentioned carbon nanotubes can be produced, for example, by the method described in JP-A-06-157016. The above conductive polymer nano The wire can be produced, for example, by the method described in JP-A-2006-241334 and JP-A-2010-76044. A commercially available product can also be used as the above-mentioned conductive fiber.

(Method for producing particles coated with conductive fibers)

The particles (A) coated with the conductive fibers can be produced by mixing the particulate material and the conductive fibers in a solvent, and can be produced, for example, by any of the following methods (1) to (4).

(1) mixing a dispersion liquid (referred to as "particle dispersion liquid") in which the particulate matter is dispersed in a solvent, and a dispersion liquid (referred to as "fiber dispersion liquid") in which the conductive fibers are dispersed in a solvent, The particles of the coated conductive fibers of the present invention (or the dispersion of the particles coated with the conductive fibers) are obtained by removing the solvent as needed.

(2) After the conductive fibers are blended in the above-mentioned particle dispersion and mixed, the particles of the coated conductive fibers of the present invention (or the dispersion of the particles coated with the conductive fibers) are obtained by removing the solvent.

(3) After the particulate matter is blended into the fiber dispersion and mixed, the particles of the coated conductive fiber of the present invention (or the dispersion of the particles coated with the conductive fiber) are obtained by removing the solvent.

(4) After the particulate material and the conductive fiber are blended in a solvent and mixed, the particles of the coated conductive fiber of the present invention (or the dispersion of the particles coated with the conductive fiber) are obtained by removing the solvent. .

In the present invention, the method of the above (1) is preferred in that a particle of the homogeneous coated conductive fiber can be obtained.

Examples of the solvent used in the production of the particles of the coated conductive fiber of the present invention include water; alcohols such as methanol, ethanol, propanol, isopropanol, and butanol; acetone, methyl ethyl ketone (MEK), and methyl group. Ketones such as isobutyl ketone (MIBK); aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; diethyl ether, dimethoxyethane, tetrahydrofuran, and An ether such as an alkyl group; an ester of methyl acetate, ethyl acetate, isopropyl acetate or butyl acetate; a guanamine such as N,N-dimethylformamide or N,N-dimethylacetamide; acetonitrile; A nitrile such as propionitrile or benzonitrile. These systems may be used singly or in combination of two or more kinds (i.e., as a mixed solvent). In the present invention, among them, an alcohol or a ketone is preferred.

Further, the resin (B) to be described later contains a liquid curable compound (for example, an epoxy compound), and can also be used as a solvent. By using a liquid curable compound as a solvent, a film-like adhesive containing particles (A) and resin (B) covering the conductive fibers can be formed without removing the solvent.

The viscosity of the solvent is not particularly limited, and the viscosity at 25 ° C is preferably 10 cP or less (for example, 0.1 to 10 cP), particularly preferably 0.1 to 5 cP, in order to efficiently produce the particles coated with the conductive fibers. Further, the viscosity of the solvent at 25 ° C can be measured using, for example, an E-type viscometer (rotor: 1° 34' × R24, number of revolutions: 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 preferably 120 ° C or less, in order to efficiently produce the particles coated with the conductive fibers.

The content of the particulate matter in the case where the particulate matter and the conductive fiber are mixed in a solvent is, for example, 100 parts by weight of the solvent, for example It is about 0.1 to 50 parts by weight, preferably 1 to 30 parts by weight, and the content of the above-mentioned conductive fiber is, for example, about 0.1 to 50 parts by weight, preferably 1 to 30 parts by weight, per 100 parts by weight of the solvent. By controlling the content of the particulate matter and the conductive fiber to the above range, it is possible to more efficiently produce the particles of the coated conductive fiber.

The ratio of the particulate matter to the conductive fiber when the particulate material and the conductive fiber are mixed in the solvent is preferably a ratio of the surface area of the particulate matter to the projected area of the conductive fiber [surface area/projection The area is, for example, a ratio of about 100/1 to 100/100, preferably 100/10 to 100/50. By controlling the above ratio within the above range, it is possible to more efficiently produce particles coated with the conductive fibers. Further, the surface area of the particulate matter can be obtained by multiplying the specific surface area obtained by the BET method (according to JIS Z8830) by the mass (usage amount) of the 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; particularly 100 or 300) by using an electron microscope (SEM, TEM). The conductive fiber was subjected to a scanning electron microscope image, and the projected area of the conductive fibers was calculated using an image analyzer, and the average was obtained by arithmetic mean.

After mixing the particulate matter and the conductive fibers, the particles of the coated conductive fibers can be obtained as a solid by removing the solvent. The removal of the solvent is not particularly limited, and can be carried out, for example, by a known or conventional method such as heating or vacuum distillation. Further, the solvent does not necessarily need to be removed. For example, the dispersion of the particles (A) coated with the conductive fibers can be added to the resin (B) as it is.

As described above, the particles coated with the conductive fibers can be produced by mixing the raw materials (particulate matter and conductive fibers) in a solvent, and it is advantageous in terms of production cost without requiring complicated steps. .

In particular, by using a particulate material having an average particle diameter A [μm], and an average length of, for example, A × 0.5 [μm] or more (preferably, A × 1.0 [μm] or more, a particularly good A × 1.5 [μm] The conductive fiber of the above) can be used as a combination of a particulate material and a conductive fiber to more efficiently produce particles coated with the conductive fiber. In particular, in the case of a spherical material having a true spherical shape or a substantially true spherical shape, it is preferred to use a particulate matter having an average circumference B [μm] and an average length (B × 1/6) [μm] or more (compare Preferably, B [μm] or more) of conductive fibers. Further, the average circumferential length of the particulate matter can be determined by a sufficient number (for example, 100 or more, preferably 300 or more; particularly 100, 300, etc.) by using an electron microscope (SEM, TEM). The particulate matter is subjected to a scanning electron microscope image, and the circumference of the particulate matter is measured and averaged.

The ratio of the particulate matter and the conductive fibers constituting the particles of the coated conductive fiber of the present invention is such that the ratio of the surface area of the particulate material to the projected area of the conductive fiber [surface area/projected area] is, for example, 100/1. In the ratio of 100/100 (especially 100/10 to 100/50), it is possible to ensure the transparency of the film-like adhesive or the cured product while imparting conductivity more efficiently. good. Further, the surface area of the particulate material and the projected area of the conductive fiber can be obtained by the above method.

Since the particles of the coated conductive fiber of the present invention have In the case of the above-described structure, it is possible to impart excellent conductivity (especially, conductivity in the thickness direction) by adding a small amount to the cured product, and it is possible to form a cured product excellent in transparency and conductivity.

In the case where the particles of the coated conductive fiber of the present invention have flexibility (for example, a state in which the 10% compressive strength is 10 kgf/mm ² or less), the film-like adhesive containing the particles of the coated conductive fiber is used. When the packaged material of the semiconductor element having the fine unevenness is used, the particles coated with the conductive fiber are deformed and adhered to the thin portion in accordance with the uneven structure, and it is possible to prevent the occurrence of a portion having poor conductivity and to form a conductive portion. A semiconductor device with excellent performance.

The particles (A) coated with the conductive fibers can be used singly or in combination of two or more. The content (doping amount) of the particles (A) coated with the conductive fibers in the film-like adhesive is, for example, about 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, per 100 parts by weight of the resin (B). More preferably, it is 0.1 to 2 parts by weight. Further, in the film-like adhesive, the content of the particles (A) of the coated conductive fibers is preferably 0.01 to 10% by weight, more preferably 0.1 to 5% by weight based on the total amount (100% by weight) of the film-like adhesive. %, particularly preferably from 0.1 to 2% by weight.

The content (doping amount) of the particulate matter (particulate matter contained in the fine particles coated with the conductive fibers) in the film-like adhesive is preferably 0.005 to the total amount (100% by weight) of the film-like adhesive. 5% by weight, more preferably 0.05 to 2.5% by weight, particularly preferably 0.05 to 1% by weight.

The content (the amount of the conductive fibers) of the conductive fibers (the conductive fibers contained in the fine particles coated with the conductive fibers) in the film-like adhesive is preferably 0.005 to the total amount (100% by weight) of the film-like adhesive. 5 heavy The amount %, more preferably 0.05 to 2.5% by weight, particularly preferably 0.05 to 1% by weight.

When the particles (A) coated with the conductive fibers are contained in the above range, a film-form adhesive or a cured product excellent in conductivity and transparency can be obtained. When the content of the particles (A) coated with the conductive fibers is less than the above range, the conductivity of the film-like adhesive or the cured product may be insufficient depending on the application. On the other hand, if the content of the particles of the coated conductive fibers is outside the above range, the transparency of the film-like adhesive or the cured product may be insufficient depending on the application.

In the film-like adhesive of the present invention, the conductive fibers are contained in a state in which the particulate matter is coated, and even if the amount of the conductive material is reduced to the above range, hardening with sufficient conductivity can be formed. Things. Therefore, the reduction in transparency due to the inclusion of the conductive material can be minimized, and the raw material cost can be drastically reduced.

[Resin (B)]

The resin (B) of the present invention may be in a sheet shape at normal temperature (5 to 35 ° C), and the cured product obtained by curing the resin (B) may have transparency. In addition, the total light transmittance of the cured product having a thickness of 10 μm in the visible light wavelength region is, for example, 87% or more, preferably 90% or more. The total light transmittance of the cured product in the visible light wavelength region can be measured in accordance with JIS K7361-1.

As a method of maintaining the shape of the resin (B) which has been formed into a sheet shape at normal temperature, the following methods etc. are mentioned.

1. A curable compound having a cationically polymerizable group and/or a radical polymerizable group in one molecule, and blended in a liquid state at normal temperature a method for reducing the adhesiveness of a compound having a solid content at a normal temperature; 2. a curable compound having two or more types of mixed hardening mechanisms (for example, a curable compound having a cationically polymerizable group in one molecule) a method of reducing the adhesiveness by hardening a curable compound which is hardened by one of the hardening mechanisms after being formed into a sheet shape, and a curable compound having a radical polymerizable group in one molecule; a method in which a curable compound having a cationically polymerizable group or a radical polymerizable group in one molecule is formed into a sheet shape, and then a part of a cationically polymerizable group or a radical polymerizable group is reacted to reduce the tackiness; and After the curable compound having a cationically polymerizable group and a radical polymerizable group in one molecule is formed into a sheet shape, one of the cationically polymerizable group or the radical polymerizable group is reacted to reduce the tackiness. Methods.

The resin (B) of the present invention preferably contains at least a curable compound having a cationically polymerizable group and/or a radical polymerizable group in one molecule (including a curable compound which is liquid at normal temperature and at normal temperature) It is a solid resin). The cationically polymerizable group may, for example, be an epoxy group or the like. In addition, examples of the radical polymerizable group include a (meth)acryl fluorenyl group and a vinyl group.

Examples of the curable compound having a cationically polymerizable group in one molecule include an epoxy group containing an unsaturated group (for example, an epoxidized polybutadiene, an epoxidized butadiene-styrene block copolymer, etc.) ), a copolymerized epoxy compound (for example: glycidyl methacrylate and a copolymer of styrene, a glycidyl methacrylate copolymer with styrene and methyl methacrylate, a copolymer of glycidyl methacrylate and cyclohexylmaleimide, (meth)acrylic acid 3, a copolymer of 4-epoxycyclohexylmethyl ester and styrene, a copolymer of 3,4-epoxycyclohexylmethyl (meth)acrylate and a copolymer of styrene and methyl methacrylate), a phenolic epoxy compound (For example, a phenol which is obtained by reacting a phenol such as phenol, cresol, a halogenated phenol or an alkylphenol with formaldehyde under an acidic catalyst, and reacting with epichlorohydrin and/or methylepichlorohydrin a compound such as a bisphenol type epoxide (for example, a bisphenol A type epoxy resin (bisphenol A diglycidyl ether obtained by condensing bisphenol A with epichlorohydrin), bisphenol F type epoxy Resin (bisphenol F diglycidyl ether obtained by condensing bisphenol F with epichlorohydrin), bisphenol S type epoxy resin (bisphenol S condensed by condensing bisphenol S with epichlorohydrin) Glycerol ether)], phenolic methane type epoxy compounds (for example, phenolic methane, cresol, methane, etc. with epichlorohydrin and/or methyl chloroform) Reacting the compound obtained) and the like. These may be used alone or in combination of two or more.

Examples of the curable compound having a radical polymerizable group in one molecule include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and (meth)acrylic acid. Butyl methacrylate, amyl (meth) acrylate, hexyl (meth) acrylate, etc. alkyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, Hydroxybutyl (meth) acrylate, caprolactone modified 2-hydroxyethyl (meth) acrylate, etc., hydroxyl group-containing (meth) acrylates; methoxy diethylene glycol (meth) acrylate Ethoxydiethylene glycol (meth) acrylate, isooctyloxy diethylene glycol (meth) acrylate, phenoxy triethylene glycol (methyl) Polyalkylene glycol (meth) acrylates such as acrylate, methoxytriethylene glycol (meth) acrylate, methoxy polyethylene glycol (meth) acrylate, etc.; styrene; γ- Propylene oxiranyl trimethoxy decane, γ-propylene methoxy propyl triethoxy decane, γ-propylene methoxy propyl methyl dimethoxy decane, γ-propylene methoxy propyl methyl Diethoxydecane, propylene methoxy ethoxy propyl trimethoxy decane, propylene methoxy ethoxy propyl triethoxy decane, propylene decyloxy diethoxy propyl trimethoxy decane, Acrylic decane compound such as propylene methoxy diethoxy propyl triethoxy decane; diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, polyaminocarboxylic acid Ester diacrylate, trimethylolpropane triacrylate, neopentyl alcohol triacrylate, neopentyl alcohol tetraacrylate, trimethylolpropane ethylene oxide modified triacrylate, trimethylolpropane Polyalkylene oxide such as propylene oxide modified triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate Esters and polyalkyl methacrylates corresponding to the aforementioned polyalkyl acrylates; polyesters of mono-, di-, tri- or higher of polybasic acids and hydroxyalkyl (meth)acrylates Wait. These may be used alone or in combination of two or more.

Examples of the curable compound having a cationically polymerizable group and a radically polymerizable group in one molecule include an oxetanering ring (methyl group) described in JP-A-2012-242459. ) an acrylate compound or the like.

The content (mixing amount) of the resin (B) in the total amount (100% by weight) of the film-form adhesive of the present invention (the total amount when it is contained in two or more cases) is, for example, 50 to 99.99% by weight, particularly excellent 60 to 99% by weight, best It is 70 to 98% by weight.

The content (doping amount) of the curable compound having a cationically polymerizable group and/or a radical polymerizable group in one molecule of the total amount of the resin (B) contained in the film-form adhesive of the present invention is, for example, preferably 20% by weight or more, particularly preferably 20 to 100% by weight, most preferably 40 to 100% by weight. When the content of the curable compound is less than the above range, when it is used for encapsulation of an organic EL device, curing progress is insufficient, and encapsulation performance tends to be lowered.

In addition, examples of the resin component which is solid at normal temperature used in the case of the method of the above 1 include polyamine, polyester, polycarbonate, polyacetal, polyphenylene ether, and polyphenylene sulfide. Ether, polyetheretherketone, polyallyltherketone, polyamidoximine, polyetherimine, polyfluorene, polyether oxime, olefin resin, styrene resin, (methyl) An acrylic resin or the like and a polymer alloy containing the same. Further, among the curable compounds having a cationically polymerizable group and/or a radical polymerizable group in one molecule, a component which is solid at normal temperature can also be used. These may be used alone or in combination of two or more.

In the case of the method of the above 1, the content (mixing amount) of the resin component which is solid at normal temperature in the total amount (100% by weight) of the film-like adhesive of the present invention is, for example, preferably 5 to 90% by weight. It is preferably from 10 to 80% by weight, preferably from 20 to 70% by weight. If the content of the resin component which is solid at normal temperature is less than the above range, it tends to be difficult to maintain the shape of the sheet. On the other hand, if the content of the resin component which is solid at normal temperature is outside the above range, it is used in an organic EL element. When the package is packaged, there is a tendency that the progress of hardening is insufficient and the package performance is lowered.

[Other ingredients]

The film-form adhesive of the present invention may contain other components in addition to the particles (A) and the resin (B) coated with the conductive fibers. Examples of the other component include a polymerization initiator, a crosslinking agent, a curing agent, a hardening retarder, a curing accelerator, a conductive material other than the particles (A) coated with the conductive fiber, and a filler (organic filler, inorganic). Filler), polymerization inhibitor, decane coupling agent, antioxidant, light stabilizer, plasticizer, leveling agent, antifoaming agent, organic solvent, ultraviolet absorber, ion adsorbent, pigment, phosphor, release agent , surfactants, flame retardants, etc. The content of the other components in the total amount of the film-like adhesive of the present invention is, for example, 30% by weight or less, preferably 0.1 to 20% by weight, particularly preferably 0.1 to 10% by weight.

(polymerization initiator)

When the resin (B) is contained in a curable compound having a cationically polymerizable group and/or a radical polymerizable group in one molecule, the film-form adhesive of the present invention preferably contains a polymerization initiator.

When the resin (B) contains a compound having a cationically polymerizable group, it is preferred to use a known or conventional photocationic polymerization initiator (photoacid generator) as a polymerization initiator, and a thermal cationic polymerization initiation. The agent or the like can initiate cationic polymerization by performing light irradiation or heat treatment.

Examples of the photocationic polymerization initiator include sulfonium salts such as triarylsulfonium hexafluorophosphate and triarylsulfonium hexafluoroantimonate; diarylsulfonium hexafluorophosphate and diphenylphosphonium hexafluoroantimonate. Bis(dodecylbenzene) Anthracene salt such as quinone (pentafluorophenyl)borate or bismuth[4-(4-methylphenyl-2-methylpropyl)phenyl]hexafluorophosphate; triphenylsulfonium hexafluorophosphate a salt such as a salt; a pyridinium salt or the like. Commercial products such as the trade name "CPI-100P" (San-Apro Co., Ltd.) can also be used.

Examples of the thermal cationic polymerization initiator include a diazonium salt, a phosphonium salt, a phosphonium salt, a phosphonium salt, and a selenium salt. Salt, ammonium salt, etc. Also available: trade name "San-Aid SI-45", "San-Aid SI-47", "San-Aid SI-60", "San-Aid SI-60L", "San-Aid SI-80" , "San-Aid SI-80L", "San-Aid SI-100", "San-Aid SI-100L", "San-Aid SI-145", "San-Aid SI-150", "San-Aid"SI-160","San-AidSI-110L","San-AidSI-180L" (above, Sanshin Chemical Industry Co., Ltd.); trade names "CI-2921", "CI-2920", "CI-2946","CI-3128","CI-2624","CI-2639","CI-2064" (above, Japan Soda (share) system); trade name "CP-66", "CP- 77" (above, ADEKA); commercially available products such as "FC-520" (manufactured by 3M).

The amount of the polymerization initiator to be used in the cationic polymerization reaction is 100 parts by weight based on the total amount of the compound having a cationically polymerizable group contained in the film-form adhesive (in the case of two or more kinds of conditions). It is preferably 0.1 to 5 parts by weight.

Further, when the resin (B) contains a compound having a radical polymerizable group, it is preferred to use a photoradical polymerization initiator, a thermal radical polymerization initiator, or the like as a polymerization initiator. A person who initiates radical polymerization by irradiation or heat treatment.

The photoradical polymerization initiator may, for example, be a product name "Irgacure 184" (manufactured by Ciba Speciality Chemicals Co., Ltd.), acetophenone ketal, benzyl dimethyl ketone or benzophenone. Ingredients, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, dimethoxy acetophenone, dimethoxyphenyl acetophenone, diethoxy acetophenone, diphenyl bis Diphenyldisulfite, methyl phthalic acid benzoate, ethyl 4-dimethylaminobenzoate (trade name "Kayacure EPA", manufactured by Nippon Kayaku Co., Ltd.), 2,4-diethyl 2,4-diethylthioxanthone (trade name "Kayacure DETX", manufactured by Nippon Kayaku Co., Ltd.), tetrakis (tertiary butyl peroxycarbonyl) benzophenone, diphenylethylenedione, 2 -hydroxy-2-methyl-1-phenyl-propan-1-one, 4,4'-bis(diethylamino)benzophenone, 2,2'-bis(2-chlorophenyl)- 4,5,4',5'-tetraphenyl-1,2'-biimidazole (trade name "B-CIM", Baotu Valley Chemical Co., Ltd.), etc., 1-[4-(2-hydroxyl Ethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionate) Base)-benzyl]phenyl}-2-methyl-propane-1- Ketone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4- Phenyl)phenyl]-1-butanone, 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzylidenehydrazide)]ethanone (1-4- (phenylthio)-2-(O-benzoyloxime)]ethanone), 1-[9-ethyl-6-(2-methylbenzhydryl)-9H-indazol-3-yl]-1-(O -Ethyl hydrazide), bis(η5-2,4-cyclopentadien-1-yl)-bis[2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl]titanium Wait. These may be used alone or in combination of two or more. Further, a photosensitizer may be added as needed.

As the thermal radical polymerization initiator, for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'- Azobis(4-methoxy-2,4-dimethylvaleronitrile), dimethyl-2,2'-azobis(2-methylpropionate), 2,2-azobis (isobutyric acid) dimethyl ester, diethyl -2,2'-azobis(2-methylpropionate), dibutyl-2,2'-azobis(2-methylpropionate) and other azo compounds; benzamidine peroxide An organic peroxide such as lauric acid peroxide, tertiary butyl peroxytrimethyl acetate, 1,1-bis(tertiary butylperoxy)cyclohexane; hydrogen peroxide; When a peroxide is used as a radical polymerization initiator, a reducing agent may be combined as a redox type initiator.

The amount of the polymerization initiator to be used in the radical polymerization reaction is 100 parts by weight based on the total amount of the compound having a radical polymerizable group contained in the film-form adhesive (in the case of two or more kinds) Preferably, it is 0.1 to 5 parts by weight.

(crosslinking agent)

When the resin (B) is contained in a curable compound having a cationically polymerizable group and/or a radical polymerizable group in one molecule, it may contain a crosslinkable structure capable of reacting with the curable compound to form a three-dimensional crosslinked structure. Joint agent.

The crosslinking agent may be a compound having two or more groups having reactivity with the cationically polymerizable group and/or the radical polymerizable group (for example, a polyfunctional epoxy compound, a polyfunctional acrylate, or a plurality of A functional amine compound, a polyfunctional acid anhydride, a polyfunctional vinyl compound, etc.). These may be used alone or in combination of two or more.

The content of the crosslinking agent is, for example, about 0 to 20 parts by weight, preferably 0 to 10 parts by weight, per 100 parts by weight of the curable compound. By using a crosslinking agent in the above range, a cured product excellent in hardenability and excellent in strength can be obtained.

(hardening accelerator)

Examples of the hardening accelerator include 2-methylimidazole, 2-ethylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, and 1,2-dimethyl group. Imidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyano Ethyl-2-methylimidazole, 1-aminoethyl-2-methylimidazole, and the like. These may be used alone or in combination of two or more. For example, a commercial item such as the product name "CUREZOL 2PZ-CN" (made by Shikoku Chemicals Co., Ltd.) can also be used.

(Electroconductive material other than particles (A) coated with conductive fibers)

A conductive material other than the conductive particles (A) may be used as a conductive material (hereinafter referred to as "other conductive material"), and a known or conventional conductive material can be used, and is not particularly limited. For example, the above conductive fibers can also be used.

The content (the amount of blending) of the other conductive material (for example, the conductive fiber) in the film-form adhesive of the present invention is, for example, about 0 to 10 parts by weight based on 100 parts by weight of the particles of the coated conductive fiber. It is preferably 0 to 5 parts by weight, particularly preferably 0 to 1 part by weight.

[film-like adhesive]

The film-like adhesive of the present invention can be coated by using, for example, a mixing machine generally known from a revolving stirring and defoaming device, a homogenizer, a planetary mixer, a three-roll mill, a bead mill, or an ultrasonic wave. A composition obtained by uniformly mixing the particles (A) of the conductive fibers (or the dispersion of the particles (A) coated with the conductive fibers) with the resin (B) and the other components as needed, and molding the sheet into a sheet shape , for example, (1) A dispersion liquid of the particles (A) of the coated conductive fiber obtained by mixing a particulate material and a fibrous conductive material in a solvent, and a resin (B) and a separate component are required to be stirred at a predetermined ratio. And mixing the obtained composition, coating on a release paper or the like to form a sheet, and then evaporating the solvent. Drying (for example, drying at about 50 to 150 ° C for about 1 to 10 minutes), followed by a method of reacting a part of the curable compound by heating or light irradiation, or (2) by passing under The particles (A) of the coated conductive fibers obtained in the steps A and B and the resin (B) and the components obtained by stirring and mixing at a predetermined ratio are applied to a release paper or the like to form a composition. In the form of a sheet, a method of reacting a part of the curable compound by a method such as heating or light irradiation is used.

Step A: a step of obtaining a particle dispersion of the coated conductive fiber by mixing the particulate material and the fibrous conductive substance in a solvent; Step B: by coating the conductive fiber obtained from the step A The particle dispersion liquid removes a solvent (for example, distillation by heating and/or filtration under reduced pressure) to obtain a particle of the coated conductive fiber as a solid.

Further, when the composition of the coated conductive fiber-containing particles (A) and the resin (B) is applied onto a release paper or the like, it is preferred that the particles (A) coated with the conductive fibers are highly dispersed in the resin. In the state of (B), it is preferable to apply a spun machine having a rotary drive structure such as a screw to discharge the composition by the rotation of the screw, and the like. Screw rotation speed and screw The size of the wing or the like is preferably adjusted in accordance with the viscosity of the film-like adhesive and the size of the particles (A) coated with the conductive fibers.

The thickness of the film-form adhesive of the present invention is not particularly limited as long as it can achieve the purpose of protecting the semiconductor element, and is, for example, about 0.1 to 100 μm, preferably 1 to 50 μm. Moreover, the width and length of the film-form adhesive of the present invention in the surface direction are not particularly limited, and can be appropriately adjusted depending on the application.

The film-form adhesive of the present invention can be suitably used as a sheet-shaped package or the like because of the above configuration. For example, when the film-form adhesive of the present invention is used as a sheet-shaped package, the step of filling a liquid package is performed without forming a dam around the semiconductor element, and the film is directly bonded to the semiconductor element and hardened. The semiconductor element can be easily packaged and has excellent workability. In addition, when a curable compound having a cationically polymerizable group and/or a radical polymerizable group in one molecule is contained as the resin (B), it is subjected to cation or radical after bonding to the semiconductor element. Polymerization can form a cured product excellent in transparency and conductivity (particularly, conductivity in the thickness direction). In the case where the film-form adhesive of the present invention contains particles of the coated conductive fiber having flexibility, even if it is used as a sealing material of a semiconductor element having fine unevenness, the particles of the coated conductive fiber follow. The uneven structure of the semiconductor element is deformed and spread over the thin portion, and it is possible to form a semiconductor device having excellent conductivity without being able to prevent the occurrence of defects in conductivity (for example, an organic EL device or an organic transistor). , organic thin film solar cells, etc.).

When the film-form adhesive of the present invention contains a curable compound having a cationically polymerizable group and/or a radical polymerizable group in one molecule as the resin (B) and contains a photopolymerization initiator, it is carried out by Light irradiation can be rapidly hardened to form a cured product.

In the case of a coating film having a thickness of 100 μm, it is preferable to irradiate light of 500 mJ/cm ² or more with a mercury lamp or the like. Further, after the light irradiation, an oven or the like may be used, for example, heating at 40 to 150 ° C (excellently 60 to 120 ° C, preferably 80 to 110 ° C) for 10 to 200 minutes (excellently 30 to 120 minutes) ( After baking).

In addition, when the film-form adhesive of the present invention contains a curable compound having a cationically polymerizable group and/or a radical polymerizable group in one molecule as the resin (B) and contains a thermal polymerization initiator, The heat treatment can be rapidly hardened by the heat treatment to form a cured product.

For the above heat treatment, for example, it is preferably heated at a temperature of 50 to 180 ° C for about 5 minutes to 2 hours.

The cured product obtained by curing the film-like adhesive of the present invention is excellent in transparency, and the total light transmittance of the cured product (thickness: 10 μm) in the visible light wavelength region is 87% or more, preferably 90% or more. Further, the total light transmittance of the cured product in the visible light wavelength region can be measured in accordance with JIS K7361-1. Further, the turbidity (haze) of the cured product (thickness: 10 μm) is, for example, 5% or less, preferably 2% or less. Further, the turbidity of the cured product of the present invention can be measured in accordance with JIS K 7136, JIS K 7361, and ASTM D 1003.

The cured product obtained by curing the film-like adhesive of the present invention is excellent in electrical conductivity, and the electrical resistivity (at 25 ° C, 1 atm) is 0.1 Ω ‧ cm to 10 MΩ ‧ cm or so, preferably 0.1 Ω ‧ cm to 1 M Ω ‧ cm

Since the film-form adhesive of the present invention has the above-described configuration, the organic EL device (particularly, the top emission type organic EL device) is encapsulated by the following method 1, and the cured product having excellent transparency and conductivity can be used. By packaging the organic EL element, it is possible to provide an organic EL device having a long life and high reliability. Further, the light irradiation and heat treatment methods can be carried out by the above method.

<Method 1: Refer to FIG. 2>

Step 1: An organic EL element is placed on a substrate, and a film-like adhesive of the present invention is applied to the surface side of the organic EL element to cover the cover. Step 2: The film-like adhesive is cured.

As the cover (cover) or the substrate, a moisture-proof substrate is preferably used, and examples thereof include a glass substrate such as soda glass and alkali-free glass; a metal substrate such as stainless steel or aluminum; and trifluoroethylene and poly Polyvinyl fluoride-based polymer such as chlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), a copolymer of PCTFE and PVDF, a copolymer of PVDF and polyvinyl fluoroethylene, polyimine, polycarbonate, A cycloolefin resin such as dicyclopentadiene or a polyester such as polyethylene terephthalate or a resin substrate such as polyethylene or polystyrene.

The organic EL device includes a laminate of an anode/light emitting layer/negative electrode. A passivation film such as a SiN film may be provided as needed.

The film-form adhesive of the present invention can form a cured product having both transparency and conductivity. Therefore, when the organic EL device is encapsulated by using the film-like adhesive of the present invention, it is possible to protect the electrode without reliably reducing the light extraction efficiency, and it is possible to reliably electrically connect the electrodes.

Then, the organic EL device (for example, display, illumination, etc.) obtained by the above method is excellent in light extraction efficiency and high in brightness because it is protected by a cured product having both transparency and conductivity.

(Packaging sheet)

The sheet for encapsulation of the present invention is obtained by laminating a film-form substrate on the film-like adhesive. The sheet for encapsulation of the present invention includes a film-form substrate/film-like adhesive layer laminate structure, and a film-form substrate/film-like adhesive/film-like substrate laminate structure.

The film-form substrate is used to protect the surface of the film-like adhesive or to adhere to the adhesive, and is peeled off by using the film-like adhesive. The film-form substrate may be a substrate having a one-layer structure or a substrate having a multilayer structure of two or more layers.

As the film-form substrate, for example, one or two or more kinds of low-adhesive substrates composed of the following may be used: a release agent such as an anthrone-based, a long-chain alkyl group, a fluorine-based or a molybdenum sulfide-based release agent. Surface treated paper or plastic film (for example, a plastic film composed of a polyester such as polyethylene terephthalate or an olefin resin such as polyethylene or polypropylene); polytetrafluoroethylene, polychlorotrifluoroethylene, A fluorine-based polymer such as polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene, hexafluoropropylene copolymer, or a vinyl chloride or vinylidene fluoride copolymer.

[Examples]

In the following, the invention will be described in more detail based on the examples, but the invention is not limited by the examples.

Production Example 1 (manufacture of silver nanowire)

Subject to "Materials Chemistry and Physics, vol.11 4, p333-338, "Preparation of Ag nanorods with high yiels by polyol process"" to produce a silver nanowire. The specific procedure is shown below.

The ethylene glycol solution of FeCl ₃ (FeCl ₃ ^{concentration: 6 × 10 -4 M) 0.5mL} , was added to the flask has been charged with 6mL of ethylene glycol and heated to 150 ℃. Thereafter, 6 mL of an ethylene glycol mixed solution containing 0.052 M of AgNO ₃ and 0.067 M of polyvinylpyrrolidone was dropped to the above heated solution. The reaction solution thus obtained was kept at 150 ° C for 1.5 hours. Then, 10 mL of the obtained suspension was diluted with 800 mL of a mixed solvent of ethanol and acetone (ethanol: acetone = 1:1 (weight ratio)), and centrifuged (2000 rpm, 10 minutes) twice, and obtained. A dispersion of silver nanowires. A part of the obtained dispersion liquid was taken out and heat-dried to confirm the content of the silver nanowire in the dispersion, which was 2.9% by weight.

The average diameter (average roughness) and the average length of the obtained silver nanowires were measured using a scanning electron microscope (SEM) to measure the diameter (thickness) and length of 100 silver nanowires, respectively, by performing arithmetic average For the measurement, the average diameter was 80 nm, and the average length was 30 μm.

Production Example 2 (Manufacture of fine particles coated with conductive fibers)

0.3 parts by weight of plastic fine particles (trade name "Micropearl SP", manufactured by Sekisui Chemical Co., Ltd., average particle diameter: 8.5 μm) was mixed with 29.7 parts by weight of ethanol and dispersed to prepare a dispersion of plastic fine particles. Then, the dispersion of the obtained plastic fine particles was mixed with 17.4 parts by weight of the silver nanowire obtained in Production Example 1 (0.5 parts by weight of the silver nanowire), and then heated at 70 ° C while being heated at 70 ° C. The solvent was removed by stirring for 30 minutes, and fine particles coated with the conductive fibers were obtained.

Further, the surface area of the plastic fine particles (a-1) is 226.9 μm ² , and the projected area of the silver nanowires per one line is 2.4 μm ² . From the plastic fine particles (a-1) and the silver nanowires which have been loaded as described above, it is considered that 20 silver nanowires are adsorbed to one plastic fine particle (a-1), thereby calculating the surface area of the plastic fine particles ( The total surface area) / the projected area of the silver nanowire (total projected area) is about 100/15.

The particles of the coated conductive fibers obtained (magnification: 100,000) were observed by a scanning electron microscope (SEM). As a result, as shown in Fig. 1, it was confirmed that silver nanowires were adsorbed on the surface of the plastic fine particles (the surface of the plastic fine particles was covered by the silver nanowire).

Example 1

Blended with phenoxy resin (trade name "YP-50S", manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd., weight average molecular weight: 60,000), 57 parts by weight, polyfunctional epoxy resin (trade name "1032H60", Mitsubishi Chemical ( 48 parts by weight, bisphenol A type epoxy compound (trade name "jER828", manufactured by Mitsubishi Chemical Corporation, weight average molecular weight: 370) 5 parts by weight, cationic polymerization initiator (trade name "CPI- 100 parts by weight of 100 parts by weight of the particles of the coated conductive fibers obtained in Production Example 2, 100 parts by weight, and the composition (1). The obtained composition (1) was applied to a surface-treated PET film (thickness: 80 μm) using an applicator, and a film was obtained by hot air drying at 70 ° C for 10 minutes. Agent (1) (width 2 mm, thickness 10 μm).

The film-form adhesive (1) obtained was bonded to the surface of a conductive glass substrate (manufactured by Luminescence Technology Co., Ltd., size: 25 mm × 25 mm, ITO: 0.14 μm), and the PET film was peeled off.

Further, in the film-form bonding agent is then affixed conductive glass substrate, subjected to UV irradiation: a film (irradiation amount 2000mJ / cm ^2), thereafter, by post-baking at 100 ℃ 5 minutes, a Hardened material 1 of a 8.5 μm thick package layer.

Example 2

Blending a glycidyl group-containing acrylate copolymer resin (trade name "HTR-860P-3", manufactured by Nagase Chemtex Co., Ltd., weight average molecular weight: 800,000), 450 parts by weight, hydrogenated bisphenol A type epoxy resin ( Product name "EPICLONEXA-7015", manufactured by DIC Corporation, 5.89 parts by weight, hardener (trade name "XLC-LL", manufactured by Mitsui Chemicals Co., Ltd., phenol aralkyl resin) 4.51 parts by weight, hardening accelerator (trade name) "CUREZOL 2PZ-CN", manufactured by Shikoku Chemicals Co., Ltd.), 0.242 parts by weight, 64 parts by weight of cyclohexanone (manufactured by Wako Pure Chemical Industries, Ltd., special grade), and coated conductive fibers obtained in Production Example 2. The composition (2) was obtained in an amount of 0.5 part by weight of the particles. The obtained composition (2) was applied to a surface-treated PET film (thickness: 80 μm) using an applicator, and a film-like adhesive was obtained by hot air drying at 110 ° C for 15 minutes (2). ) (width 2 mm, thickness 10 μm).

The film-form adhesive (2) obtained was bonded to the surface of a conductive glass substrate (manufactured by Luminescence Technology Co., Ltd., size: 25 mm × 25 mm, ITO: 0.14 μm), and the PET film was peeled off.

Further, a conductive glass substrate was bonded to the film-form adhesive, and heat treatment was performed at 150 ° C for 1 hour to obtain a cured product 2 having a package material layer having a film thickness of 8.5 μm.

Comparative example 1

In addition to the use of Micropearl AU (mainly composed of divinylbenzene) The surface of the particulate material composed of the crosslinked polymer was replaced with the coated conductive material obtained in Production Example 2 by a gold plated product, trade name "Micropearl AU-2085", manufactured by Sekisui Chemical Co., Ltd., average particle diameter: 7.3 μm. The particles of the fibrous fibers were carried out in the same manner as in Example 1.

Comparative example 2

The same procedure as in Example 1 was carried out except that the particles of the coated conductive fibers obtained in Production Example 2 were not used.

(Evaluation of conductivity of hardened material)

With respect to the cured products obtained in Examples 1 and 2 and Comparative Examples 1 and 2, the resistance value in the thickness direction (resistivity: Ω ‧ cm) was measured using a 2-terminal tester.

(Evaluation of transparency of film-like adhesive or cured product thereof)

For the cured products obtained in Examples 1, 2, and Comparative Examples 1 and 2, an ultraviolet ray visible spectrophotometer (trade name "V-650DS", manufactured by JASCO Corporation) was used to measure the visible light wavelength region. Total light transmittance (value of two sheets of conductive glass substrate) in (wavelength: 450 nm).

The above results are shown in Table 1 below.

[Industrial availability]

The film-like adhesive of the present invention can easily encapsulate a semiconductor element by directly bonding to a semiconductor element and hardening, and workability excellent. Further, it is possible to form an electrically conductive cured product having excellent transparency and excellent properties. Further, the raw material cost can be reduced and it can be provided inexpensively. Therefore, the film-form adhesive of the present invention can be suitably used as a sheet-like package of a semiconductor element.

Further, the semiconductor device of the present invention encapsulated by the cured product of the film-like adhesive of the present invention is excellent in light extraction efficiency and has high luminance.

Claims (11)

A film-like adhesive comprising particles (A) coated with a conductive fiber and a resin (B), wherein the particles (A) coated with the conductive fiber contain a particulate matter having a median diameter of 0.1 to 100 μm, and a fibrous conductive material having an average thickness of 1 to 400 nm and an average length of 1 to 100 μm coated with the particulate material; the resin (B) having a cationically polymerizable group and/or a radical polymerizable group in one molecule A curable compound which is liquid at normal temperature and a curable compound which has a cationically polymerizable group and/or a radical polymerizable group in one molecule and which is solid at normal temperature. The film-like adhesive agent of claim 1, wherein the fibrous conductive material-coated conductive nanowires constituting the particles (A) coated with the conductive fibers. The film-like adhesive of claim 2, wherein the conductive nanowire is selected from the group consisting of a metal nanowire, a semiconductor nanowire, a carbon fiber, a carbon nanotube, and a conductive polymer nanowire. At least one. The film-like adhesive of claim 2, wherein the conductive nanowire is a silver nanowire. The film-form adhesive according to any one of claims 1 to 4, wherein the content of the particles (A) coated with the conductive fibers is 0.01 to 10% by weight based on the total amount of the film-like adhesive. The film-like adhesive according to any one of claims 1 to 4, wherein the median diameter of the particulate matter constituting the particles (A) coated with the conductive fibers is 70 to 100% of the thickness of the film-like adhesive. A use of the film-like adhesive according to any one of claims 1 to 4 for packaging of a semiconductor element. A sheet for encapsulation, which is obtained by laminating a film-form substrate of a film-like adhesive according to any one of claims 1 to 6. A cured product obtained by hardening a film-like adhesive according to any one of claims 1 to 6. The cured product of claim 9 has a total light transmittance [in terms of thickness 10 μm] in the visible light wavelength region of 87% or more. A semiconductor device in which a semiconductor element is packaged with a cured material as claimed in claim 9 or 10.