JP2003026813A - Anisotropic electroconductive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive anisotropic electroconductive material having stable physical properties, using electroconductive composite particles without causing mutual coarse aggregation of mother and daughter particles, respectively because of firm adherence of the mother particles to the daughter particles. SOLUTION: This anisotropic electroconductive material comprises electroconductive composite particles the surface of which is coated with resin daughter particles. the coating operation is carried out by blending the electroconductive mother particles bearing functional groups A on the surface, with the daughter particles bearing on the surface functional groups B reactive to the functional groups A.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an anisotropic conductive material containing conductive composite particles as an essential component.

[0002]

2. Description of the Related Art Anisotropically conductive materials have been developed in response to demands for miniaturization, thinning and high performance of electronic parts. The anisotropically conductive material is, for example, a resin material or the like that is easy to mold and contains conductive particles, and when the resin material is an insulating adhesive material and formed into a film, If this anisotropic conductive film is sandwiched between facing electrodes, and multiple electrodes are connected together by heating and pressing, the electrode connection of fine circuits can be achieved with the conventional connection technology using solder or rubber connectors. What was difficult is now possible.

[0003]

At this time, if a large amount of conductive particles are used for the purpose of improving the reliability of conduction, there is a problem that the insulation between adjacent circuits is lost due to the contact between the conductive particles. Further, since the conductive particles have a poor affinity with the resin material, it is difficult to uniformly disperse them in the resin material.

On the other hand, the metal powder and the metal-coated particles may be used alone instead of being dispersed in a matrix material such as a resin. In such an application, direct contact between the conductive particles is used. Must be avoided altogether, so its surface must be insulating.

In order to solve this problem, for example, Japanese Patent No. 2836337 and Japanese Patent No. 3050384 disclose conductive particles having an electrically insulating layer on the surface.

[0006] These publications disclose the following metal surface oxidation method, solution method, dry method and the like as a method for forming an electrically insulating layer.

(1) Metal surface oxidation method: When the surface of the conductive particles is Ni or Al, the surface of the conductive particles is heated by heating in the presence of oxygen to form an electrically insulating layer made of an oxide of Ni or Al. Is a method of forming. This method has the problems that the types of metals are limited, that the thickness of the electrically insulating layer is not sufficient, and the like.

(2) Solution method: An electrically insulative resin is dissolved in a solvent, applied on the surface of the electrically conductive particles in a solution state, and dried to form an electrically insulative resin on the surface of the electrically conductive particles. This is a method of forming an electrically insulating layer. This method has a problem that the type of resin is limited because it is necessary to dissolve the resin in a solvent, and there is a problem that it is difficult to make the thickness of the electric insulating layer sufficient and uniform.

(3) Dry method: The powder made of an electrically insulating resin and the conductive particles are collided at high speed, mixed and rubbed, or melted and adhered to each other.
This is a method of forming an electrically insulating layer made of an electrically insulating resin on the surface of conductive particles. This method has problems that productivity is not good because the amount that can be treated at one time is limited, and that the insulating layer is easily peeled off because the electrical insulating layer does not adhere sufficiently.

Therefore, an object of the present invention is to easily and firmly form an electrically insulating layer having a sufficient thickness on the surface of the conductive particles by uniformly and firmly adhering the child particles to the conductive mother particles. An object of the present invention is to provide an anisotropically conductive material which has stable physical properties and is inexpensive.

[0011]

Means for Solving the Problems The inventors of the present invention have made diligent studies in order to solve the problems of the conventional method for obtaining composite particles, and as a result, as a result, a mother particle and a child having functional groups capable of reacting with each other on the surface. The present invention has been completed by finding that the above problems can be achieved by adhering the child particles to the surface of the mother particles by mixing the particles.

That is, the anisotropic conductive material according to the present invention is a conductive composite particle in which the surface of the conductive mother particle is coated with resin particles, and the coating has a functional group A on the surface. An essential component is a composite particle obtained by mixing conductive mother particles and resin particles having a functional group B capable of reacting with the functional group A on the surface.

In the present invention, it is preferable that the mixing treatment is performed in the presence of a dispersion medium.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, according to the present invention, a conductive mother particle having a functional group A on the surface and a child particle having a functional group B capable of reacting with the functional group A on the surface are mixed and treated. By doing so, since it is characterized in that the conductive composite particles are used in which the surface of the conductive mother particles is insulation-coated with the child particles, the composite particles will be described below first.
And, the conductive composite particles may be an anisotropic conductive material by itself, but since they are often used by being dispersed in a matrix material such as a resin, a method of using them will be explained next. To do.

[Electrically Conductive Composite Particle] Here, the electrically conductive mother particle means a metal particle or a metal plating particle which is a main body of the composite particle, and the child particle is a fine particle which is a coating powder of the main body. Say.

First, the mother particles that can be used here are not particularly limited as long as at least the surface is a metal, and are either organic particles or inorganic particles (including metal particles). Good. As child particles,
Insulating resin particles are used.

The structure of the mother particles and the child particles may be a single layer structure for both particles, or may be a multilayer structure in which the surface of the core particles is coated with a coating particle or a coating component,
For example, microencapsulated particles in which porous core particles that have absorbed or adsorbed fine powder of liquid substance or solid substance are coated with coated particles or coating components, polymer-coated particles in which core particles are coated with polymer, coated with core particles Composite particles coated with particles can be used.

Examples of the above organic particles include crosslinked and non-crosslinked resin fine particles, organic pigments and waxes. As the crosslinked and non-crosslinked resin fine particles, for example, styrene resin fine particles, acrylic resin fine particles,
Methacrylic resin particles, polyethylene resin particles,
Polypropylene resin particles, silicone resin particles, polyester resin particles, polyurethane resin particles, polyamide resin particles, epoxy resin particles,
Polyvinyl butyral resin particles, rosin resin particles, terpene resin particles, phenol resin particles,
Examples thereof include melamine-based resin fine particles and guanamine-based resin fine particles.

Examples of the inorganic particles include alumina, titanium dioxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth. , Chromium oxide, cerium oxide, iron oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, fine silica powder, silicon carbide, silicon nitride, boron carbide, tungsten carbide, titanium carbide, carbon black Etc., examples of metal particles include gold, platinum, palladium, silver, ruthenium,
Rhodium, osmium, iridium, iron, nickel, cobalt, copper, zinc, lead, aluminum, titanium, vanadium, chromium, manganese, zirconium, molybdenum,
Examples thereof include powder or particles of indium, antimony, tungsten, etc., and alloys thereof.

When the mother particles themselves do not have conductivity, the conductive mother particles can be made by plating the surface of the original particles having no conductivity with metal.
Gold, silver, nickel,
Palladium, copper or alloys thereof are exemplified, and single layer plating of these metals or multilayer plating in which two or more metal plating layers are laminated may be used. The method for plating these metals on the original particles is not limited and may be any of a wet plating method and a vapor phase plating method. In the case of the wet plating method, a known electroless plating solution composition or electroplating solution composition is used. It can be carried out by a known pretreatment method or plating method.

The functional groups on the surface of the mother particles or the child particles can be arbitrarily selected so that the functional groups can be chemically bound to each other, and are not particularly limited. . As the selectable functional group on both particle surfaces, for example, an aziridine group, an oxazoline group,
Examples thereof include epoxy group, thioepoxy group, amide group, isocyanate group, acetoacetyl group, carboxyl group, carbonyl group, hydroxyl group, amino group, aldehyde group, mercapto group and sulfone group. Incidentally, these functional groups are, for example, the surface of the functional group obtained by producing resin particles by emulsion polymerization, suspension polymerization, etc., using a polymerizing monomer composition containing a monomer having the functional group. Present on the surface of the particle, or a compound having a chemical bond (including complex formation) with the particle to introduce a functional group on the surface of the particle, or a chemical bond to the particle. It may be one in which a functional group is introduced on the particle surface by chemically bonding the compound to the particle surface using a compound (including complex formation) and further reacting this compound with a compound having a functional group. Etc. are not particularly limited.

The combination of the above functional groups is specifically a combination capable of forming a covalent bond, an ionic bond, a metal bond, a coordinate bond or an electrostatic bond, preferably a covalent bond, a metal bond or a bond. A combination of functional groups capable of forming a position bond, more preferably a combination of functional groups capable of forming a covalent bond. When forming composite particles by the hetero-aggregation method using electrostatic coupling, p
Care should be taken not to dissolve the metal by the H modifier.

As a method for fixing the child particles on the surface of the mother particles, a mixing treatment of the mother particles and the child particles in the presence of a dispersion medium is preferable. By performing the treatment in this way, it is possible to apply the excessive impact force to the particles without impairing the physical properties thereof, and to attach the child particles uniformly to the individual particles regardless of the shape or the unevenness of the mother particles.

The volume average particle diameter of the mother particles is preferably in the range of 1 to 50 μm when used as an anisotropic conductive material. When the volume average particle diameter of the mother particles is less than 1 μm, reliable conduction between circuits is difficult to obtain when used as an anisotropic conductive material. On the other hand, when the volume average particle diameter of the mother particles exceeds 50 μm, when it is used as an anisotropic conductive material, it is difficult to obtain a reliable conduction between circuits because the particle size distribution does not become sharp easily, and the adjacent circuit is also difficult to obtain. It is not preferable because it easily causes a short circuit.

On the other hand, the volume average particle diameter of the child particles is 1/3 or less, preferably 1/5 of the volume average particle diameter of the mother particles.
Or less, more preferably 1/10 or less. When the volume average particle diameter of the child particles is larger than 1/3 of the volume average particle diameter of the mother particles, the adhered state is not stable, and the mother particles and the child particles are excessively aggregated.

The method for producing such a composite particle is not limited, but it has a mother particle having a functional group on the particle surface and a functional group capable of reacting with the functional group of the mother particle on the particle surface. A method of mixing and treating the child particles in the presence of a dispersion medium is preferable.

By this manufacturing method, the child particles can be extremely firmly attached to the mother particles, and the individual particles can be uniformly and stably manufactured without coarse aggregation between the mother particles and the child particles, and further high solid processing is possible. Therefore, it is excellent in productivity and also advantageous in cost.

The dispersion medium is not particularly limited, but examples thereof include water, alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol and butyl alcohol; liquid paraffin, decane, decene, methylnaphthalene, decalin, Hydrocarbons such as kerosene, diphenylmethane, toluene, dimethylbenzene, ethylbenzene, diethylbenzene, propylbenzene, cyclohexane, and partially hydrogenated triphenyl; polydimethylsiloxane, partially octyl-substituted polydimethylsiloxane, partially phenyl-substituted polydimethylsiloxane,
Silicone oils such as fluorosilicone oils; halogenated hydrocarbons such as chlorobenzene, dichlorobenzene, bromobenzene, chlorobiphenyl, chlorodiphenylmethane; Daifloyl (manufactured by Daikin Industries, Ltd.),
Fluoride such as demnum (manufactured by Daikin Industries, Ltd.);
Examples include ester compounds such as ethyl benzoate, octyl benzoate, dioctyl phthalate, trioctyl trimellitate, dibutyl sebacate, ethyl (meth) actylate, butyl (meth) acrylate, and dodecyl (meth) acrylate. These can be used alone or in combination of two or more.

The concentration of particles used in the above mixing treatment varies depending on the types and particle sizes of mother particles and child particles,
The content is usually 10% by volume or more, preferably 20% by volume or more, and more preferably 30% by volume or more with respect to the dispersion medium. If the concentration of the particles to be subjected to the mixing treatment is less than 10% by volume, the contact probability between the mother particles and the child particles will be low, and therefore the treatment will take a long time and it is not economically preferable.

The above reaction conditions vary depending on the types of functional groups of the mother particles and the child particles, the particle concentration, the particle specific gravity, etc., but the reaction temperature is 20 to 200 ° C., preferably 30 to 1
The temperature is 50 ° C., and more preferably 40 to 120 ° C.
Further, the stirring speed may be any speed that can uniformly disperse the mother particles and the child particles.

The method for synthesizing the mother particles and the child particles having a functional group on the particle surface is not particularly limited, and conventionally known fine particle production techniques and functional group introduction techniques to the fine particle surfaces are appropriately used. However, it is needless to say that the synthetic method of the mother particle and the child particle of the present invention is not limited thereto.

(1) Particles made from organic compounds (including organic polymer compounds) (in the present specification, sometimes referred to simply as organic particles) As a method for producing organic particles having a functional group on the particle surface, , But is not particularly limited, for example, suspension polymerization,
A particle forming method such as emulsion polymerization or dispersion polymerization can be used. As a method of introducing a functional group, there are a method of containing one or more kinds of monomers having a functional group, a method of containing a segment of an initiator as a functional group, a method of introducing from a dispersant or a surfactant, and the like. These methods may be used alone or in combination of two or more.
Further, it is also possible to introduce a new functional group by treating the particles with a compound having a functional group capable of reacting with the functional group thus introduced.

Examples of the monomer having a functional group include, for example,
Those having a carboxyl group such as acrylic acid, methacrylic acid and itaconic acid, those having a hydroxyl group such as β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate and allyl alcohol, Those having a methylol group such as N-methylol acrylamide and N-methylol methacrylamide, those having an amino group such as dimethylaminoethyl acrylate and dimethylaminoethyl methacrylate, those having an acid amide such as acrylamide and methacrylamide, glycidyl acrylate, Those having a glycidyl group such as glycidyl methacrylate and glycidyl allyl ether, 2-vinyl-2-oxazoline,
Examples thereof include those having an oxazolyl group such as 2-vinyl-4-methyl-2-oxazoline and 2-isopropenyl-2-oxazoline. Further, those having a hydrolyzable silyl group such as γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, and vinyltrimethoxysilane can also be used for introducing the functional group.

Examples of the monomer containing no reactive functional group include methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, 2-ethylhexyl acrylate, Cyclohexyl acrylate, tetrahydrofurfuryl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, trifluoroethyl methacrylate, perfluorooctylethyl methacrylate, methyl vinyl ether, ethyl Vinyl ether, n-propyl vinyl ether, iso-
Use butyl vinyl ether, n-butyl vinyl ether, styrene, α-methyl styrene, acrylonitrile, methacrylonitrile, vinyl acetate, vinyl chloride, vinyl fluoride, vinylidene fluoride, ethylene, propylene, isopropylene, chloroprene, butadiene, etc. You can

Examples of the crosslinkable monomer include divinylbenzene, divinylnaphthalene, ethylene glycol dimethacrylate, diethyl glycol dimethacrylate, triethylene glycol dimethacrylate, trimethylolpropane triacrylate, allyl methacrylate and t-butylaminoethyl. Monomers having two or more unsaturated groups in the molecule, such as methacrylate, tetraethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, N, N-divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfonic acid. The body or the like can be used as necessary.

Examples of the polymerization initiator used for the polymerization include lauryl peroxide, benzoyl peroxide,
Oil-soluble initiators such as cumene hydroperoxide, 2,2-azobisisobutyronitrile and 2,2-azobis-2,4-dimethylvaleronitrile, water-soluble initiators such as potassium persulfate, sodium persulfate and ammonium persulfate The initiator may be used alone or as a mixture of two or more depending on the polymerization method.

Examples of the dispersion stabilizer include polymers such as polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, polyvinyl alcohol and polyvinyl alkyl ether, alkyl sulfate ester salts, alkylbenzene sulfonate salts, alkyl phosphate ester salts and polyoxy. Anionic surfactants such as ethylene alkyl sulfate ester salts, nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, alkylamine salts, quaternary ammonium salts, etc. A cationic surfactant, a zwitterionic surfactant such as lauryldimethylamine oxide, and the like can be used alone or in combination of two or more, if necessary.

(2) Particles made of an inorganic compound (in the present specification, sometimes referred to simply as inorganic particles) Inorganic particles having a functional group on the particle surface (including metal particles)
The method for producing is not particularly limited, and includes, for example, a method of directly utilizing a hydroxyl group existing on the surface of the inorganic particles, a method of newly introducing a functional group by a chemical surface treatment, and the like. As the surface treatment agent, γ
-A silane coupling agent such as glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane Conventionally known ones such as titanium coupling agents and aluminum coupling agents having a reactive functional group can be used. Also,
As a method of introducing a functional group into the surface of metal particles, the present inventors have particularly proposed the method described in JP-A-2000-3973.
The method described in Japanese Patent No. 7), that is, the method of treating metal particles with a mercapto compound, and the method of treating the treated metal particles with a polymer compound having a functional group or a monomer or oligomer thereof can be preferably used. . further,
It is also possible to introduce a new functional group by treating the particles with a compound having a functional group capable of reacting with the functional group thus introduced.

[Anisotropic Conductive Material] The method of using the composite particles obtained as above as the anisotropic conductive material is not limited. For example, it can be dispersed in a matrix material such as a resin material and used as a film adhesive or a paste adhesive. In this case, the compounding amount of the composite particles in the anisotropically conductive material is not particularly limited because the surface of the composite particles is insulative and even if a large amount is mixed, it is difficult to short-circuit between adjacent circuits, but it is usually 1 The range is from 99 to 99% by weight.

The above composite particles can also be used as an anisotropically conductive material by using only the composite particles.

The application will be described in detail below.

(1) Film Adhesive The anisotropic conductive film can be produced by a known method. The composite particles are dispersed in an insulating adhesive and then formed into a film.

As the insulating adhesive, a thermoplastic material used for an insulating sheet or the like or a curable material which is curable by heat or light can be widely applied. Among them, the epoxy adhesive is used for a short time. It can be preferably applied because it is curable, has good workability in connection, and has excellent adhesiveness due to its molecular structure. Epoxy adhesives include, for example, polymer epoxy, solid epoxy and liquid epoxy, phenoxy resin and liquid epoxy, epoxy mixed with urethane, polyester, NBR, etc. as a main component, and latent curing agent or coupling agent. It is generally composed of a system to which various modifiers such as the above and a catalyst are added.

(2) Paste Adhesive An anisotropic conductive paste adhesive may be prepared by a known method. An anisotropic conductive adhesive can be obtained by mixing the above-mentioned composite particles in an insulating adhesive similar to that of the above-mentioned adhesive film and a suitable solvent to form a paste and applying it to the use surface.

(3) Use of composite particles alone It is also possible to give anisotropic conductivity by arranging only the above composite particles between the electrodes. In this case, the method of use is not limited, but for example, as disclosed in Japanese Patent No. 2995244, the composite particles having the surface coated with an insulating adhesive are mixed in a liquid and then applied on the base film. There is a method in which only the composite particles are arranged in a plane by drying.

[0046]

The present invention will be described in more detail below. In the following, "part" means "part by weight".

Conductive mother particles were manufactured by the following synthesis examples.

(Synthesis Example 1) 100 parts of copper particles having a volume average particle diameter of 6 μm, 0.27 part of 2,4,6-trimercapto-S-triazine and 20 parts of methanol were mixed and stirred at 65 ° C. Heated for 30 minutes. After cooling this,
Unreacted 2,4,6-trimercapto-S-triazine was washed off with methanol and further washed with tetrahydrofuran. This copper particle and an epoxy resin (YDCN-
703, manufactured by Tohto Kasei Co., Ltd.) and a solution of 5 parts dissolved in 25 parts of tetrahydrofuran, and mixed with stirring with 65 parts.
Heat at 30 ° C. for 30 minutes. After cooling this, the unreacted epoxy resin was washed off with tetrahydrofuran and heated to 50 ° C.
And dried for 24 hours with a hot air drier to obtain mother particles (1) composed of copper particles having an epoxy group on the particle surface.

(Synthesis Example 2) Eposta-GP (manufactured by Nippon Shokubai Co., Ltd., benzoguanamine / melamine / formaldehyde resin particles, particle diameter 5.3 μm, coefficient of variation 4.8%)
After electroless nickel plating, was further electroless gold plated to obtain conductive particles.

100 parts of the conductive particles, 1 part of 2,4,6-trimercapto-S-triazine, 100 parts of methanol
The parts were mixed and heated at 65 ° C. for 30 minutes with stirring.
After cooling this, the unreacted 2,4,6-trimercapto-S-triazine was washed off with methanol and heated to 50 ° C.
Was dried for 24 hours with a hot air drier to obtain a conductive mother particle (2) having a mercapto group on the particle surface.

Child particles were produced by the following synthesis example.

(Synthesis Example 3) 70 parts of styrene in a reaction vessel,
27 parts of n-butyl acrylate, 3 parts of methacrylic acid, Hitenol N-08 (polyoxyethylene alkyl ether ammonium sulfate, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.)
3 parts and 300 parts of water were put and dispersed with a hiscotron (manufactured by Microtec Nition Co., Ltd.) to obtain a monomer suspension. This suspension was stirred under a nitrogen atmosphere at 70
The mixture was heated to ° C, 1 part of potassium persulfate was added, and the mixture was further heated at 70 ° C for 6 hours with stirring to carry out emulsion polymerization. The volume average particle diameter was 0.3 μm as a result of measuring the particle diameter of the emulsion particles in this polymerization liquid with a particle size distribution analyzer LA-910W (manufactured by Horiba, Ltd.). In this way, an emulsion having a particle concentration of 24.9% by weight and having child particles (3) having a carboxyl group on the surface thereof was dispersed was obtained. The emulsion was dried, and the glass transition temperature of the obtained polymer was measured by DSC7 (manufactured by Perkin Elmer Co., Ltd.). As a result, it was found to be 59.3 ° C.

(Synthesis Example 4) 80 parts of styrene in a reaction vessel,
15 parts of n-butyl acrylate, 5 parts of glycidyl methacrylate, 0.5 part of Hitenol N-08, and 300 parts of water were added and dispersed with a hyscotron to obtain a monomer suspension. This suspension was heated to 70 ° C. under stirring under a nitrogen atmosphere, 1 part of potassium persulfate was added, and further heated at 70 ° C. for 6 hours with stirring to carry out emulsion polymerization. As a result of measuring the particle size in this polymerization liquid with a particle size distribution measuring device LA-910W, the volume average particle size was 0.2 μm. In this way, an emulsion having a particle concentration of 24.7% and having child particles (4) having a glycidyl group on the surface thereof was dispersed was obtained. The emulsion was dried, and the glass transition temperature of the obtained polymer was measured by DSC7.
It was ℃.

An anisotropic conductive material was obtained by using the conductive mother particles (1) and (2) and the child particles (3) and (4) obtained above according to the following examples.

(Example 1) 100 parts of mother particles (1) consisting of the copper particles obtained in Synthesis Example 1, 50 parts of water, Hitenol N-
08 0.075 parts, child particles (3) 20 obtained in Synthesis Example 3
The parts were mixed and heated with stirring at 70 ° C. for 3 hours to react the epoxy groups on the mother particle surface with the carboxyl groups on the child particle surface.

This was cooled, washed with water, and then dried with a hot air dryer at 50 ° C. to obtain polymer-coated copper particles (5). Observation with a scanning electron microscope (SEM) confirmed that the surfaces of the mother particles were uniformly covered with the child particles.

The polymer-coated copper particles (5) thus obtained are blended in an epoxy adhesive varnish containing a curing agent at a solid content volume ratio of 20% to a thickness of 20 μm.
The adhesive film of 1 was cast on a release film to prepare an anisotropic conductive adhesive film.

This anisotropic conductive film was sandwiched between an ITO electrode on a glass substrate and an FPC having a tin circuit plated on a copper circuit having a pitch of 50 μm and a thickness of 35 μm, and 170
Connected by thermocompression bonding conditions ℃ -20kgf / cm ² -20 seconds. When a voltage was applied to this circuit, the connection resistance was 8.
It was 3 Ω, and it was confirmed to be conductive.

(Example 2) 100 parts of conductive mother particles (2) composed of plated particles obtained in Synthesis Example 2 and 100 parts of water, 0.2 part of Hitenol N-08, and the child obtained in Synthesis Example 4 particle
(4) Mix 20 parts (child particles) and stir at 70 ° C for 3
By heating for a time, the mercapto group on the surface of the mother particle and the glycidyl group on the surface of the child particle were reacted.

This was cooled, washed with water, and then dried with a hot air dryer at 50 ° C. to obtain polymer-coated plated particles (6).
Got Observation with a scanning electron microscope (SEM) confirmed that the surfaces of the mother particles were uniformly covered with the child particles.

The polymer-coated plated particles (6) thus obtained were formed into a film in the same manner as in Example 1 to prepare a circuit. When a voltage was applied to this circuit, the connection resistance was 4.9Ω and it was confirmed that the circuit was conductive.

[0062]

The anisotropic conductive material according to the present invention uses composite particles in which child particles are attached to the surface of conductive mother particles by a chemical reaction. This composite particle is a composite particle in which child particles are firmly fixed, and is a low-cost composite particle that can be processed by high solids, has a large throughput, can be industrially produced.

The composite particles that have been mixed in the presence of a dispersion medium have good physical properties because they are not subjected to physical impact, and the child particles are free to move and react regardless of the shape and unevenness of the mother particles. As a result, each particle can be treated uniformly.

Therefore, the anisotropically conductive material of the present invention has stable physical properties and is inexpensive.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08L 101: 02 C08L 101: 02 F term (reference) 4F070 AA45 AB06 AC74 AC76 AC83 DB04 DC00 5G301 DA05 DA06 DA10 DA29 DD03 5G307 AA02 AA08 HA02 HB03 HC01

Claims (2)

[Claims] 1. A conductive composite particle having a surface of a conductive mother particle coated with resin particles, wherein the coating reacts with the conductive mother particle having a functional group A on the surface and the functional group A. An anisotropically conductive material, which contains, as an essential component, composite particles obtained by a mixing treatment with resin particles having functional groups B on the surface thereof. 2. The anisotropic conductive material according to claim 1, wherein the mixing treatment is performed in the presence of a dispersion medium.