JP4313664B2 - Protruding conductive particles, coated conductive particles, and anisotropic conductive material - Google Patents

Description

The present invention relates to a method for producing protruding particles capable of binding child particles firmly to the surface of base particles, and to protruding particles, protruding conductive particles and anisotropic conductive material using the protruding particle manufacturing method. .

Protrusion particles having protrusions on at least a part of the surface of the base particle have a function not found in the base particles, and thus are expected to be used in various applications. For example, when used as a gap material or conductive particles, an effect of preventing the movement of particles between the substrate and the electrode is expected. Further, the matte effect due to the irregular reflection of the surface protrusions can make it opaque (whitening) without adding pigments or dyes, and thus is expected as display particles and paints for electronic paper.

In addition, aluminum electrodes that have recently been used in electronic circuits have a problem in that an oxide film is easily formed on the surface, and when an attempt is made to connect circuits with conductive particles, conduction is hindered due to the oxide film. . Even in such a case, if projecting conductive particles having conductive projections on the surface are used, it is considered that the projecting portion can break through the oxide film of the circuit and ensure conduction, thereby improving connection reliability.

As a method for producing such protruding particles, conventionally, for example, a method in which organic or inorganic child particles are adhered to the surface of the substrate particles by a mechanochemical method (high-speed air flow method) or the like has been performed. However, in this method, it is extremely difficult to control the amount of the child particles attached to the surface of the base material particles, and since the bond between the base particles and the child particles is only a physical binding force, it is extremely difficult. There is a problem that the child particles may be peeled off from the base particles in a single particle forming process or a dispersing process in a medium.

In addition, as a method of manufacturing the protruding conductive particles, for example, in Patent Document 1, when a nickel conductive film is formed on the surface of the base particle by electroless plating, the nickel coating and the minute nickel that becomes the nucleus of the protrusion are used. A method is disclosed in which conductive protrusions are formed on the surface of substrate particles by simultaneously depositing particles and forming a nickel coating while taking in nickel fine particles. However, this method has a problem that it is difficult to control the number and size of the protrusions to be obtained because it is very difficult to control the amount and size of the nickel fine particles to be deposited.

JP 2000-243132 A

In view of the above-described situation, the present invention provides a method for producing a projecting particle capable of firmly binding a child particle to the surface of a base particle, a projecting particle using the method for producing the projecting particle, a projecting conductive particle, and An object is to provide an anisotropic conductive material.

The present invention includes adding a child particle to a seed particle dispersion to prepare a seed / child particle composite liquid, adding a polymerizable unsaturated monomer to the seed / child particle composite liquid, Using a method for producing protruding particles, comprising a step of preparing a polymerizable droplet in which the polymerizable unsaturated monomer is absorbed in a seed / child particle complex, and a step of polymerizing the polymerizable droplet Protruding conductive particles comprising protruding particles and a metal layer formed on the surface of the protruding particles .
The present invention is described in detail below.

As a result of intensive studies, the inventors of the present invention have found that if the polymerizable droplets are polymerized after attaching the child particles to the surface of the polymerizable droplets, the child particles are particles formed by polymerizing the polymerizable droplets. As a result, the present invention has been completed.
In the present specification, the polymerizable droplet has a polymerizable unsaturated monomer on at least the surface,
It means particles capable of polymerizing the polymerizable unsaturated monomer by means such as heating.

Such polymerizable droplets are not particularly limited. For example, polymerizable droplets that are intermediates for producing resin fine particles by suspension polymerization method or emulsion polymerization method, or resin fine particles by seed polymerization method are used. Examples thereof include seed particles (swelling droplets) that have absorbed a polymerizable unsaturated monomer that is an intermediate during production.

As a method for producing the protruding particles of the present invention, for example, a dispersion in which at least a polymerizable unsaturated monomer and a medium are mixed and polymerizable droplets containing the polymerizable unsaturated monomer are dispersed in the medium is used. A method comprising a step of preparing, adding a child particle to the dispersion, attaching the child particle to the surface of the polymerizable droplet, and polymerizing the polymerizable droplet to which the child particle is attached is suitable. (Such a method is hereinafter also referred to as Embodiment 1).
The production method of the protruding particles of the present invention will be explained by explaining the embodiment 1 below.

In the method for producing protruding particles of Embodiment 1, first, a polymerizable unsaturated monomer and a medium are mixed to prepare a dispersion in which polymerizable droplets containing the polymerizable unsaturated monomer are dispersed in the medium. The process to do is performed. This step can be performed in the same manner as conventionally known suspension polymerization method, emulsion polymerization method and the like.

As said polymerizable unsaturated monomer, the 1 type (s) or 2 or more types of a non-crosslinkable monomer and / or a crosslinkable monomer can be used.
Examples of the non-crosslinkable monomer include styrene monomers such as styrene, α-methylstyrene, p-methylstyrene, p-chlorostyrene, chloromethylstyrene; (meth) acrylic acid, maleic acid, anhydrous Carboxyl group-containing monomers such as maleic acid; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cetyl (Meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, ethylene glycol (meth) acrylate, trifluoroethyl (meth) acrylate, pentafluoropropyl (meth) acrylate, etc. Kill (meth) acrylates; 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth) acrylate, oxygen atom-containing (meth) acrylates such as glycidyl (meth) acrylate; (meth) acrylonitrile Nitrile-containing monomers such as; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, and propyl vinyl ether; acid vinyl esters such as vinyl acetate, vinyl butyrate, vinyl laurate, vinyl stearate, vinyl fluoride, vinyl chloride, and vinyl propionate And unsaturated hydrocarbons such as ethylene, propylene, butylene, methylpentene, isoprene and butadiene.

Examples of the crosslinkable monomer include tetramethylolmethane tetra (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and dipentaerythritol. Hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri (meth) acrylate; glycerol di (meth) acrylate,
Polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth)
Polyfunctional (meth) acrylates such as acrylate; triallyl (iso) cyanurate, triallyl trimellitate, divinylbenzene, diallyl phthalate, diallyl acrylamide, diallyl ether, etc .; γ- (meth) acryloxypropyltrimethoxysilane, trimethoxy Silane-containing monomers such as silylstyrene and vinyltrimethoxysilane; dicarboxylic acids such as phthalic acid; diamines; diallyl phthalate, benzoguanamine, triallyl isocyanate, and the like.
These polymerizable unsaturated monomers may be used alone or in combination of two or more.

The medium is not particularly limited as long as it is incompatible with the polymerizable unsaturated monomer, and examples thereof include water, methanol, ethanol, dimethyl sulfoxide, dimethylformamide, and a mixed solution thereof. Of these, water is preferred because it is easy to handle.

The polymerizable droplets containing the polymerizable unsaturated monomer formed in the medium constitute base particles by being polymerized.

In order to stably disperse the polymerizable droplets containing the polymerizable unsaturated monomer in the medium, for example, a dispersion stabilizer such as polyvinyl alcohol, polyvinyl pyrrolidone, polyoxyethylene, or cellulose is added. It is preferable.
In addition, additives such as auxiliary stabilizers, pH adjusters, anti-aging agents, antioxidants, preservatives and the like that are usually used in suspension polymerization methods and emulsion polymerization methods may be added to the medium.

The method for preparing a dispersion in which polymerizable droplets containing the polymerizable unsaturated monomer are dispersed in a medium is not particularly limited. For example, the polymerizable unsaturated monomer is added to the medium, Examples thereof include a method of forming polymerizable droplets by stirring; a method of extruding a polymerizable unsaturated monomer into a medium from a fine nozzle, a porous film having a uniform aperture, and the like.
In the above stirring, a homomixer, a homogenizer, or the like may be used in addition to a normal stirring blade, and an ultrasonic wave may be used in this case.
Since the particle size of the substrate particles depends on the particle size of the polymerizable droplets in the dispersion, it can be easily controlled by the type and amount of the dispersion stabilizer, the stirring method and strength, the nozzle diameter, the aperture, etc. Can do.

In the method for producing protruding particles according to Embodiment 1, the step of adding child particles to the dispersion and aggregating the child particles on the surface of the polymerizable droplets is then performed.
The said child particle comprises the protrusion part of the protrusion particle | grains obtained.
The child particles are not particularly limited, and examples thereof include those made of a resin, those made of an insulating inorganic material such as silica, and those made of a metal. Of these, a resin is preferable. It does not specifically limit as said resin, For example, the resin etc. which superpose | polymerize the above-mentioned polymerizable unsaturated monomer are mentioned. These resins may be used alone or in combination of two or more.

The child particles preferably have a polymerizable unsaturated group on the surface. Thereby, since it copolymerizes when superposing | polymerizing the said polymeric droplet, the coupling | bonding of a child particle and a base particle becomes very firm.
The method for introducing a polymerizable unsaturated group into the surface of the child particle is not particularly limited. For example, 1) a method of converting the functional group on the surface of the child particle into a polymerizable unsaturated group by a one-stage or multi-stage reaction. 2)
A method of adding a monomer having two kinds of polymerizable unsaturated groups having different polymerization properties when preparing the child particles is exemplified.

As the method 1), for example, a method of introducing vinyl groups by reacting vinyl silane with the surface of the child particles made of silica; a method of introducing methacrylic groups by reacting methacrylic acid with the surface of the child particles made of glycidyl methacrylate. A method of introducing a methacryl group by reacting 2-methacryloyloxyethyl isocyanate on the surface of a child particle made of hydroxyethyl methacrylate;

Examples of the monomer having two kinds of polymerizable unsaturated groups having different polymerizability in the method 2) include 2-hydroxy-3-acryloyloxypropyl methacrylate, allyloxy polyethylene glycol-polyethylene glycol monomethacrylate, and the like. It is done.

Although it does not specifically limit as a particle diameter of the said child particle, A preferable minimum is 50 nm. 50
When it is less than nm, when the protruding particles of the present invention are used as a gap material or conductive particles, the height of the protrusion becomes insufficient, and an effect of preventing the movement and breaking through the oxide film on the surface of the aluminum electrode can be obtained. There may not be. Moreover, a preferable upper limit is 20% of the particle size of the substrate particles. When it exceeds 20%, the protrusions are larger than necessary with respect to the particle diameter of the base particles, and the characteristics of the base particles may not be expressed.

When the child particles are added to the dispersion, the child particles adhere to the surface of the polymerizable droplets by van der Waals force or electrostatic interaction. This adhesion method is a method called heteroaggregation. According to the hetero-aggregation method, as in the dry method using a conventional high-speed stirrer or a hybridizer, the base particles and the child particles are not deformed, and the child particles are laminated and adhered, The child particles are not melted and cannot be made into a single particle due to the coalescence of the particles, and the child particles can be adhered to the surface of the polymerizable droplets uniformly and in a single layer.

The number of protrusions formed by the child particles may be appropriately selected according to the particle diameter of the base particles, the particle diameter of the child particles, and the use of the protrusion particles of the present invention. The preferred lower limit is 0.5% and the preferred upper limit is 50%. If it is less than 0.5%, the number of projections is too small, and even if the resulting projection particles are used as a gap material, the movement preventing effect may not be obtained. There may be no protrusion in the direction, and the effect of breaking through the oxide film may not be obtained. If it exceeds 50%, the physical properties of the protruding particles are greatly affected by the physical properties of the child particles, and the characteristics of the base particles may not be exhibited. In the present specification, the exclusive area means the projected area of the child particles on the surface of the base material particles.
The exclusive area can be controlled by the amount, concentration, surface potential, surface charge, medium polarity, pH, ionic strength, etc. of the child particles.

In the method for producing the protruding particles of Embodiment 1, the step of polymerizing the polymerizable droplets to which the child particles are attached is then performed. Specifically, for example, polymerization is started by heating or irradiating light using a polymerization initiator. The heating temperature is appropriately determined depending on the composition and molecular weight of the polymerizable unsaturated monomer to be used, the type and amount of the polymerization initiator, etc., but is usually in the range of 30 to 100 ° C.

The polymerization initiator may be contained in a polymerizable droplet or may be dissolved in a medium. When it is contained in the polymerizable droplet, a method of preparing the polymerizable droplet after dissolving in the polymerizable unsaturated monomer can be mentioned. Also, when dissolving in the medium, dissolve the polymerization initiator in the medium in advance, or after preparing the polymerizable droplet, dissolve it in the same liquid as the medium and add it to the dispersion of the polymerizable droplet The method of doing is mentioned.

The polymerization initiator is not particularly limited, and examples thereof include peroxides such as hydrogen peroxide and benzoyl peroxide; 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethyl). Azonitrile compounds such as valeronitrile), 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane-1-carbonitrile), 2- (carbamoylazo) isobutyronitrile; 2 , 2′-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide}, 2,2′-azobis {2-methyl-N- [2- (1 -Hydroxybutyl)] propionamide}, 2,2
Azoamide compounds such as' -azobis [2-methyl-N- (2-hydroxyethyl) propionamide]; 2,2'-azobis [2- (2-imidazolin-2-yl) propane],
2,2′-azobis [2- (3,4,5,6-tetrahydropyrimidin-2-yl) propane], cyclic azoamide compounds such as hydrochlorides and sulfates thereof; 2,2′-azobis (2-
Azoamidine compounds such as amidinopropane) and 2,2′-azobis [N- (2-carboxyethyl) -2-methyl-propionamidine]; azocarboxylic acid compounds such as 2,2′-azobis (4-cyanovaleric acid) An azooxime compound such as 2,2′-azobis (2-methylpropionamidooxime);

Through the above operation, base particles are formed from the polymerizable droplets, and projecting particles in which the child particles are bonded to the surface of the base particles are obtained.

Furthermore, as Embodiment 2, for example, a step of mixing seed particles and a medium containing a polymerizable unsaturated monomer to prepare a dispersion in which seed particles are dispersed in the medium, and polymerization onto the seed particles A step of preparing polymerizable droplets by absorbing the polymerizable unsaturated monomer, a step of adding child particles to the dispersion and attaching the child particles to the surface of the polymerizable droplets, and a polymerizability with the child particles attached And a method of polymerizing droplets.
In Embodiment 2, a polymerizable droplet in which a polymerizable unsaturated monomer is absorbed in a seed particle is used as the polymerizable droplet in place of the polymerizable droplet containing a polymerizable unsaturated monomer. Except for the above, this embodiment is the same as Embodiment 1 above.

According to the method for producing a protruding particle of the present invention, it is possible to easily manufacture a protruding particle in which a child particle is bonded to the surface of a base particle, and a conventional method such as suspension polymerization, emulsion polymerization, seed polymerization, etc. By applying the above, the size of the base particles can be easily adjusted, and the number and density of the protrusions can be controlled by adjusting the addition amount of the child particles. Furthermore, in the protruding particles obtained by the method for manufacturing protruding particles of the present invention, the bonding between the base particles and the child particles is strong, and even if the plating described later is applied, the protruding particles are not easily peeled off and are stably protruded. Conductive particles can be produced.
Protrusion particles formed using the method for producing protrusion particles of the present invention are also one aspect of the present invention.

The projecting conductive particles comprising the projecting particles of the present invention and the metal layer formed on the surface of the projecting particles are also one aspect of the present invention.
The metal is not particularly limited as long as it has conductivity. For example, gold, silver, copper, platinum, zinc, iron, tin, lead, aluminum, cobalt, indium, nickel, chromium,
Metals such as titanium, antimony, bismuth, germanium, cadmium, silicon, ITO,
Examples thereof include metal compounds such as solder.
The metal layer may have a single layer structure or a laminated structure including a plurality of layers. In the case of a laminated structure, the outermost layer is preferably made of gold. When the outermost layer is made of gold, protruding conductive particles having high corrosion resistance and low contact resistance can be obtained.

The method for forming the metal layer on the surface of the protruding particles is not particularly limited, and examples thereof include known methods such as physical metal vapor deposition and chemical electroless plating. An electroless plating method is preferred. Examples of the metal layer that can be formed by the electroless plating method include gold, silver, copper, platinum, palladium, nickel, rhodium, ruthenium, cobalt, tin, and alloys thereof.

Although it does not specifically limit as thickness of the said metal layer, A preferable minimum is 0.005 micrometer and a preferable upper limit is 1 micrometer. When the thickness is less than 0.005 μm, a sufficient effect as the conductive layer may not be obtained. When the thickness exceeds 1 μm, the specific gravity of the obtained protruding conductive particles becomes too high, or the hardness is not sufficient to allow sufficient deformation. Sometimes. A more preferred lower limit is 0.01
The upper limit is more preferably 0.3 μm.

If the projecting conductive particles of the present invention are used for conductive connection between a substrate and an electronic component or the like, even if an oxide film is formed on the surface of an aluminum electrode or the like, the oxide film can be broken through, Extremely high connection reliability can be obtained.

The coated conductive particles comprising the protruding conductive particles of the present invention and the insulating particles covering the surfaces of the protruding conductive particles are also one aspect of the present invention. The coated conductive particles of the present invention can also be suitably used for conductive connection between a substrate and an electronic component.

The insulating particles are not particularly limited as long as they are insulative, and examples thereof include those made of an insulating resin such as silica and the like. Among these, an insulating resin is preferable. The insulating resin is not particularly limited. For example,
Examples include resins used for the above-described core particles. These resins may be used alone,
Two or more kinds may be used in combination.

The preferable lower limit of the particle diameter of the insulating particles is 5 nm, and the preferable upper limit is 1000 nm. 5
If it is less than nm, the distance between adjacent coated conductive particles is smaller than the hopping distance of electrons, and leakage tends to occur. If it exceeds 1000 nm, the pressure and heat required for thermocompression bonding become too large. There is. A more preferred lower limit is 10 nm, and a more preferred upper limit is 500 nm.

The insulating particles preferably have a positive charge. By having a positive charge, it is possible to perform bonding with the protruding conductive particles using the hetero-aggregation method, and since the insulating particles repel each other, the aggregation of the insulating particles is suppressed. Thus, a single coating layer can be formed. That is, when the insulating particles are positively charged, the insulating particles adhere to the protruding conductive particles as a single layer.

The protruding conductive particles or the coated conductive particles of the present invention can be suitably used as an anisotropic conductive material by being dispersed in an insulating binder resin. Such an anisotropic conductive material is also one aspect of the present invention.
In this specification, the anisotropic conductive material includes an anisotropic conductive film, an anisotropic conductive paste, an anisotropic conductive adhesive, an anisotropic conductive ink, and the like.

The insulating binder resin is not particularly limited as long as it is insulative. For example, acrylic ester, ethylene-vinyl acetate resin, styrene-butadiene block copolymer and hydrogenated product thereof, and styrene-isoprene block copolymer. And thermoplastic resins such as hydrogenated products thereof; thermosetting resins such as epoxy resins, acrylate resins, melamine resins, urea resins, phenol resins; acrylic acid esters of polyhydric alcohols, polyester acrylates, polycarboxylic acids Examples thereof include resins that are cured by ultraviolet rays such as unsaturated esters, electron beams, and the like. Especially, the adhesive agent hardened | cured with a heat | fever and / or light is suitable.

In the anisotropic conductive material of the present invention, in addition to the binder resin which is an essential component and the protruding conductive particles of the present invention, for example, a filler, a filler, etc. 1 or 2 of various additives such as softeners, plasticizers, polymerization catalysts, curing catalysts, colorants, antioxidants, heat stabilizers, light stabilizers, UV absorbers, lubricants, antistatic agents, flame retardants, etc. More than one kind may be added.

According to the present invention, a method for producing a projection particle capable of firmly binding a child particle to the surface of a substrate particle, a projection particle using the method for producing the projection particle, a projection conductive particle, and an anisotropic conductivity Can provide material.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

Example 1
(1) Preparation of child particles 10 equipped with a four-neck separable cover, stirring blade, three-way cock, cooling tube, and temperature probe
In a 00 mL separable flask, 70 mmol of methyl methacrylate, 10 mmol of glycidyl methacrylate, 20 mmol of ethylene glycol dimethacrylate, 3 mmol of phenyldimethylsulfonium methyl sulfate, 2,2′-azobis [N- (2-
Carboxyethyl) -2-methyl-propionamidine] tetrahydrate 3 mmol and distilled water 470 mL were weighed, then stirred at 200 rpm, polymerized at 70 ° C. for 5 hours in a nitrogen atmosphere, and having an epoxy group on the surface Child particles were obtained. Next, ethylenediamine 30mmo
l was added and reacted at 70 ° C. for 1 hour to convert the epoxy group to an amino group.
After completion of the reaction, unreacted monomers, polymerization initiators, etc. are removed by centrifugation, and distilled water 4
After adding 00 mL and dispersing by ultrasonic irradiation, 30 mmol of glycidyl methacrylate was added and reacted at 70 ° C. for 1 hour to convert the amino group into a polymerizable methacryl group. After completion of the reaction, unreacted substances are removed and washed twice by centrifugation, and further dispersed with distilled water to polymerize the surface with an average particle diameter of 305 nm, a CV value of 8.8%, and a solid content of 10%. A child particle dispersion having a functional group was obtained.
The particle size and distribution of the child particles are the dynamic light scattering particle size distribution size (DLS800, manufactured by Otsuka Electronics Co., Ltd.).
0).

(2) Preparation of seed particles 10 equipped with a four-neck separable cover, stirring blade, three-way cock, cooling tube, and temperature probe
In a 00 mL separable flask, 500 mmol of styrene, 85 mmol of n-octyl mercaptan, 2 mmol of potassium persulfate, 2.5 mmol of sodium chloride and 585 mL of distilled water were weighed and stirred at 200 rpm for 24 hours at 70 ° C. in a nitrogen atmosphere. Polymerization was performed. After completion of the reaction, removal of unreacted monomer, polymerization initiator, etc. by centrifugation and washing were carried out twice, and further dispersed with distilled water to obtain an average particle diameter of 900 nm and a CV value of 3.2%.
A seed particle dispersion having a solid content of 10% was obtained.

(3) Production of projecting particles 50 equipped with a four-neck separable cover, a stirring blade, a three-way cock, a cooling tube, and a temperature probe
In a 0 mL separable flask, 10 g of the obtained seed particle dispersion and 90 mL of distilled water
After weighing, 1 g of the obtained child particle dispersion was dropped while stirring to make the seed particles and the child particles composite. Next, 0.05 g of sodium lauryl sulfate and polyvinyl alcohol 3
A 20% aqueous solution was added to obtain a seed / child particle composite solution.
Separately, divinylbenzene 120 g, benzoyl peroxide 3 g, sodium lauryl sulfate 0.
7 g and 800 mL of distilled water were mixed and emulsified with a homogenizer to obtain a polymerizable monomer emulsion.
The resulting polymerizable monomer emulsion is added to the seed / child particle composite solution, stirred at 100 rpm, and absorbed to the seed / child particle composite at room temperature under a nitrogen stream for 24 hours. To obtain polymerizable droplets. Next, after setting the stirring speed to 200 rpm, the polymerizable droplets were polymerized by heating to 70 ° C. to obtain protruding particles.
Observation using a scanning electron microscope revealed that the obtained protruding particles had an average particle diameter of 4.01 μm, a CV value of 3% in the portion without protrusions, and an average of 24 protrusions per one. (13.5% as the projected area).

(4) Production of protruding conductive particles The obtained protruding particles were degreased, sensitized, and activated to generate palladium nuclei on the resin surface, thereby forming electroless plating catalyst nuclei. Next, it was immersed in an electroless nickel plating bath to form a nickel plating layer. Furthermore, electroless displacement gold plating was performed on the surface of the nickel layer to obtain protruding conductive particles.
When the obtained conductive protrusion particles were observed using a scanning electron microscope, the surface of the particles including the protrusions was metal-plated, and the average number of protrusions was 24. Did not decrease.

(5) Production of anisotropic conductive material Epoxy resin (manufactured by Yuka Shell Epoxy, Epicoat 828) 10 as a binder resin
After 0 parts by weight, 2 parts by weight of trisdimethylaminoethylphenol and 100 parts by weight of toluene were sufficiently mixed using a planetary stirrer, the resultant was coated on a release film so that the thickness after drying was 10 μm. Was evaporated to obtain an adhesive film.
Subsequently, an epoxy resin (manufactured by Yuka Shell Epoxy, Epicoat 82) is used as a binder resin.
8) 100 parts by weight, 2 parts by weight of trisdimethylaminoethylphenol and 100 toluene
After adding the conductive conductive particles obtained in parts by weight and mixing well using a planetary stirrer, the coated film was applied on a release film so that the thickness after drying was 7 μm, and toluene was evaporated to make protrusions An adhesive film containing conductive particles was obtained. In addition, the compounding quantity of the protruding conductive particles was such that the content in the film was 50,000 / cm ² .
By laminating the obtained adhesive film and the adhesive film containing protruding conductive particles at room temperature, an anisotropic conductive film having a thickness of 17 μm having a two-layer structure was obtained.

(Comparative Example 1)
(1) Protrusion particle manufacture Resin particles were obtained in the same manner as in Example 1 (3) except that no dispersion of the dispersion particles was added. The obtained resin particles had a particle size of 3.9 μm.
After 10 g of the obtained resin particles and 1 g of the child particles (dried) obtained in Example 1 were combined using a hybridization system (manufactured by Nara Machinery Co., Ltd.) at 120 ° C. for 5 minutes, The mixture was cooled and uncomposited child particles were removed by an air stream to obtain protruding particles.
When observed using a scanning electron microscope, the number of protrusions obtained was an average of 30 protrusions. However, the number of protrusions per particle was large, and many particles without protrusions were observed. .

(2) Preparation of protruding conductive particles The protruding conductive particles were obtained in the same manner as in Example 1 except that the obtained protruding particles were used.
Observation of the protruding conductive particles obtained using a scanning electron microscope revealed that the surface of the particles including the protrusions was metal-plated, but the average number of protrusions was 15 and the protrusions were formed by plating operation. The number was decreasing.

(3) Production of anisotropic conductive material An anisotropic conductive film was obtained in the same manner as in Example 1 except that the obtained projecting conductive particles were used.

(Comparative Example 2)
(1) Preparation of protruding conductive particles The resin particles having an average particle diameter of 3.9 μm prepared in Comparative Example 1 were degreased, sensitized and activated to produce palladium nuclei on the resin surface, The catalyst core was used. Next, it was immersed in an electroless nickel plating bath to form a nickel plating layer. On this occasion,
Nickel with protrusions by inducing the self-decomposition of nickel in the vicinity of the plating film by dropping an appropriate amount of L-dead thein at the desired stage of the nickel plating reaction, and by proceeding with plating while taking in the fine particles of the nickel. Layers were formed. Next, electroless displacement gold plating was performed on the surface of the nickel layer to obtain protruding conductive particles.
When observed with a scanning electron microscope, the average number of protrusions per unit was 35, but the number and size of the protrusions varied greatly, and many protrusions with a size close to 1 μm were observed in the circumferential direction. It was. In addition, fine particles made of only nickel / gold, which are extremely difficult to remove, were observed.

(2) Production of anisotropic conductive material An anisotropic conductive film was obtained in the same manner as in Example 1 except that the obtained protruding conductive particles were used.

(Evaluation)
The anisotropic conductive films prepared in Example 1 and Comparative Examples 1 and 2 were cut into a size of 5 × 5 mm. This has a width of 200 μm, a length of 1 mm and a height of 0 with a lead wire for resistance measurement on one side.
. After affixing the glass substrate having the same aluminum electrode on the center of a 2 μm, L / S 20 μm aluminum electrode, aligning the electrodes so that they overlap each other.
The bonded portion of the glass substrate was subjected to thermocompression bonding under a pressure bonding condition of 10 N and 100 ° C., and then the resistance value between the electrodes and the presence or absence of leakage between the electrodes were evaluated.
The results are shown in Table 1.

According to the present invention, a method for producing a projection particle capable of firmly binding a child particle to the surface of a substrate particle, a projection particle using the method for producing the projection particle, a projection conductive particle, and an anisotropic conductivity Can provide material.

Claims (4)

Adding a child particle to the seed particle dispersion to prepare a seed / child particle composite liquid; adding a polymerizable unsaturated monomer to the seed / child particle composite liquid; Protruding particles using a method for producing protruding particles, the method comprising: preparing a polymerizable droplet in which a saturated monomer is absorbed in a seed / child particle complex; and polymerizing the polymerizable droplet ; A protruding conductive particle comprising a metal layer formed on a surface of the protruding particle. A coated conductive particle comprising: the protruding conductive particle according to claim 1; and an insulating particle covering a surface of the protruding conductive particle. An anisotropic conductive material, wherein the protruding conductive particles according to claim 1 are dispersed in an insulating binder resin. An anisotropic conductive material, wherein the coated conductive particles according to claim 2 are dispersed in an insulating binder resin.