JP2012014979A - Flat conductive particle manufacturing method, flat conductive particle, and resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable high-precision classification processing to be performed for flat conductive particles at a relatively high speed.SOLUTION: A flat conductive particle manufacturing method comprises a flat conductive particle manufacturing step and a wet classification step. The flat conductive particle manufacturing step manufactures flat conductive particles. The wet classification step uses wet sieve classification to classify flat conductive particles. In the flat conductive particle manufacturing step of this flat conductive particle manufacturing method, flat conductive particles are preferably manufactured in a wet method.

Description

  The present invention relates to a method for producing flat conductive particles. The present invention also relates to flat conductive particles produced by the production method. The present invention also relates to a resin composition containing such flat conductive particles.

  In the past, a technique (for example, dry-mixing and pulverizing copper powder and solid particulate organic compound obtained from the atomization method, electrolysis method, and chemical reduction method, and then adjusting the particle size with an air classifier having a fixed sieve mesh) (for example, Japanese Patent Application Laid-Open No. 11-264001, etc.) and a technique of “flaking copper powder using a dry counter-impact jet mill and classifying the particles with a cyclone and then collecting them with a back filter” (for example, Japanese Patent Application Laid-Open No. 2006-2006). -210214 gazette etc.) is proposed.

Japanese Patent Laid-Open No. 11-264001 JP 2006-210214 A

  However, as described above, when the air classification method is adopted as the classification method, the frequency of clogging in the sieve mesh becomes relatively high, and the classification processing speed becomes relatively low. On the other hand, when the cyclone classification method is adopted as the classification method, classification processing can be performed at a relatively high speed, but precise classification cannot be performed.

  An object of the present invention is to enable flat conductive particles to be subjected to precise classification at a relatively high speed.

(1)
The manufacturing method of the flat electroconductive particle which concerns on 1 aspect of this invention is equipped with a flat electroconductive particle manufacturing process and a wet classification process. In the flat conductive particle manufacturing process, flat conductive particles are manufactured. In the wet classification step, the flat conductive particles are classified by wet sieving.

  As a result of intensive studies by the inventors of the present application, it has been clarified that when flat conductive particles are subjected to wet sieving and classification, precise classification can be performed at a relatively high speed. For this reason, if this flat conductive particle manufacturing method is used, the flat conductive particles can be precisely classified at a relatively high speed.

(2)
In the method for producing flat conductive particles according to one aspect of the present invention, it is preferable that the flat conductive particles are produced in a wet manner in the flat conductive particle producing step.

  In this way, not only can the flat conductive particles be easily taken out in the flat conductive particle production process, but the flat conductive particles can be supplied to the wet classification process as they are. .

(3)
In the method for producing flat conductive particles according to one aspect of the present invention, in the wet classification step, the flat conductive particles are in a range of 0.1 wt% to 50 wt% with respect to the liquid medium. The slurry of the flat conductive particles whose concentration has been adjusted is supplied to the sieve.

  As a result of intensive studies by the inventors of the present application, it has been clarified that such a flat conductive particle slurry can be subjected to a precise classification process at a higher speed. For this reason, in this way, the flat conductive particles can be precisely classified at a higher speed in the flat conductive particle manufacturing process.

(4)
The flat conductive particles according to another aspect of the present invention are manufactured by the method for manufacturing flat conductive particles according to any one of the above aspects (1) to (3).

  The flat conductive particles are precisely classified. For this reason, when this flat electroconductive particle is utilized for an electroconductive paste etc., it can fully suppress producing malfunctions, such as clogging a syringe.

(5)
The resin composition according to another aspect of the present invention contains the flat conductive particles and the resin according to the aspect (4). The “resin” mentioned here includes a thermosetting resin and a thermoplastic resin. In addition, the “resin” includes one in a state before the final form (so-called precursor).

  The flat conductive particles are precisely classified. For this reason, when this resin composition is utilized as a conductive paste, it is possible to sufficiently suppress problems such as clogging of syringes.

1 is a front view of a wet classifier according to an embodiment of the present invention. 1 is a plan view of a wet classifier according to an embodiment of the present invention. It is AA sectional drawing of the wet classifier which concerns on embodiment of this invention.

  The manufacturing method of the flat electroconductive particle which concerns on embodiment of this invention is equipped with a flat electroconductive particle manufacturing process and a wet classification process. Hereinafter, these steps will be described in detail.

  <Details of each step of manufacturing method of flat conductive particles>

1. Flat conductive particle manufacturing process In the flat conductive particle manufacturing process, conductive particles manufactured by a mechanical pulverization method, a chemical reduction method, an electrolysis method, an atomizing method, etc. are used as an attritor, stamp mill, ball mill, It is flattened (flaked and scaled) in a wet environment by a pulverizer such as a bead mill or a jet mill.

  The “conductive particles” used herein are not particularly limited, and examples thereof include metal particles and core-shell type conductive particles. In addition, these electroconductive particles may be used independently and may be used together.

  The above-mentioned “metal particles” are not particularly limited. For example, gold, silver, copper, platinum, nickel, palladium, indium, iron, chromium, tantalum, tin, lead, zinc, cobalt, titanium, tungsten, bismuth, Examples include single metal particles such as silicon, antimony, aluminum, and magnesium, and alloy particles. Of these, silver single metal particles and alloy particles are preferred. This is because silver single metal particles and alloy particles have good electrical conductivity and thermal conductivity, are hardly oxidized, and are excellent in workability. Although it does not specifically limit as an alloy particle of silver, For example, the silver-copper alloy, silver-palladium alloy, silver-tin alloy, silver-zinc alloy, silver which contain silver 50weight% or more, Preferably 70weight% or more -Alloy particles such as magnesium alloy and silver-nickel alloy are preferably mentioned. In addition, these metal particles may be used independently and may be used together.

  The average particle diameter of the conductive particles is preferably 0.5 μm or more and 30 μm or less, and more preferably 0.5 μm or more and 10 μm or less. This is because when the average particle diameter of the conductive particles is within this range, the aggregation of the conductive particles hardly occurs and the conductive particles exhibit good conductivity.

  As described above, the conductive particles are obtained by a mechanical pulverization method or the like. However, depending on the type of conductive particles, the conductive particles having a target particle size may not be obtained. Therefore, the conductive particles are preferably obtained by any one of a chemical reduction method, an electrolysis method, and an atomization method. In particular, when producing silver particles having a particle diameter of less than 10 μm, a water atomization method in which molten metal is sprayed into water or a chemical reduction method in which a silver nitrate solution is reduced with a reducing agent is suitable.

  This flat conductive particle manufacturing process is performed in a humid environment as described above. Although it does not specifically limit as a solvent which produces the moist environment, For example, water, alcohol, glycol, ester, ether, ketone, aromatic hydrocarbon, unsaturated carboxylic acid etc. are mentioned. These solvents may be used alone or in combination of two or more.

  Although it does not specifically limit as alcohol, For example, methanol, ethanol, n-propanol, isopropanol, butanol, pentanol etc. are mentioned. Although it does not specifically limit as glycol, For example, ethylene glycol etc. are mentioned. Although it does not specifically limit as ester, For example, methyl acetate, isopropyl acetate, etc. are mentioned. Although it does not specifically limit as ether, For example, dimethyl ether, diethyl ether, diphenyl ether, tetrahydrofuran, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether etc. are mentioned. Although it does not specifically limit as a ketone, Acetone, dimethyl ketone, methyl ethyl ketone, diethyl ketone, etc. are mentioned. The aromatic hydrocarbon is not particularly limited, and examples thereof include toluene and xylene. The unsaturated aliphatic carboxylic acid is not particularly limited. For example, acrylic acid, crotonic acid, isocrotonic acid, undecylenic acid, oleic acid, elaidic acid, cetreic acid, erucic acid, brassic acid, sorbic acid, linoleic acid, linolenic acid Examples include acids, arachidonic acid, propiolic acid and stearic acid.

  The flat conductive particles obtained by flattening the conductive particles preferably have a particle diameter of 0.1 μm to 100 μm.

  2. Wet classification process

  In the wet classification step, the flat conductive particles produced in the flat conductive particle production step are subjected to wet sieving and classification by the wet classification apparatus shown in FIGS. 1 to 3 without drying. The slurry-like flat conductive particles finally obtained in the flat conductive particle manufacturing process may be supplied to the wet classification process as they are, or the solvent used in the flat conductive particle manufacturing process. The concentration may be adjusted with the same solvent or a different solvent and then supplied to the wet classification process. The concentration of the flat conductive particles in the slurry-like flat conductive particles is preferably from 0.1% by weight to 50% by weight with respect to the solvent, and preferably from 0.5% by weight to 30% by weight with respect to the solvent. More preferred.

  As shown in FIGS. 1 to 3, the wet classifier 100 described above mainly includes a multistage sieve unit 110, a connecting member 120, a vibration device 130, a discharge tube 140, a discharge container 150, and a supply hose 160. The Hereinafter, after detailed description of each of these components, a method of using the wet classifier 100 will be described.

  (1) Configuration of wet classifier

A. As shown in FIGS. 1 to 3, the multi-stage sieve unit 110 mainly includes three sieves 111 a, 111 b, 111 c, two intermediate rings 112 a, 112 b, a tray 113 with a discharge pipe, a lid body 116, It is composed of five O-rings Or and two clamps 117. Hereinafter, for convenience of explanation, the sieve denoted by reference numeral 111a is referred to as “first sieve”, the sieve denoted by reference numeral 111b is referred to as “second sieve”, and the sieve denoted by reference numeral 111c is referred to as “third sieve”. The intermediate ring denoted by reference numeral 112a is referred to as a “first intermediate ring”, and the intermediate ring denoted by reference numeral 111b is referred to as a “second intermediate ring”.

  As shown in FIG. 3, the sieves 111a, 111b, and 111c are mainly composed of frame bodies Fa, Fb, and Fc and meshes Ma, Mb, and Mc. In the present embodiment, the frame bodies Fa, Fb, Fc of the first sieve 111a, the second sieve 111b, and the third sieve 111c are all the same. Moreover, in this Embodiment, the mesh Ma of the 1st sieve 111a is the coarsest, and the mesh Mc of the 3rd sieve 111c is the finest. The mesh Mb of the second sieve 111b is finer than the mesh Ma of the first sieve 111a and coarser than the mesh Mc of the third sieve 111c. For this reason, when the slurry of flat conductive particles is flowed from above, the flat conductive particles are sequentially classified according to the eyes of the meshes Ma, Mb, and Mc.

  As shown in FIG. 3, air holes P are formed in the intermediate rings 112 a and 112 b. The intermediate rings 112a and 112b suppress the air cushion phenomenon without causing the flat conductive particles and the solvent to leak out of the system by the air holes P. These intermediate rings 112a and 112b are inserted between the sieves 111a, 111b, and 111c. In the present embodiment, the first intermediate ring 112a is inserted between the first sieve 111a and the second sieve 111b, and the second intermediate ring 112b is inserted between the second sieve 111b and the third sieve 111c. .

  The receiving tray 113 with the discharge pipe is a substantially cylindrical receiving container with a bottom plate. As shown in FIG. 1, a discharge pipe 114 is provided through the side surface of the tray 113 with the discharge pipe. For this reason, the solvent and the flat conductive particles that have fallen to the tray 113 with the discharge pipe are discharged to the discharge container 150 through the discharge pipe 114 and the discharge tube 140 when the liquid level exceeds a certain level.

  The lid 116 is a plate-like member as shown in FIGS. As shown in FIG. 3, the lid 116 has an opening 116 a at the center and holes (not shown) for inserting guide bars at both ends. The opening 116a is covered with the connection member 120 as shown in FIGS.

  As shown in FIGS. 1 and 3, the O-ring Or is provided between the first sieve 111a and the first intermediate ring 112a, between the first intermediate ring 112a and the second sieve 111b, and between the second sieve 111b and the second sieve 111b. Between the 3 sieves 111c and between the 3rd sieve 111c and the receiving tray 113 with a discharge pipe, the sealing performance between these members is ensured.

  As shown in FIGS. 1 and 2, the clamp 117 mainly includes a main body 118 and a lever 119, and is inserted into a guide bar 115 (described later) of the vibration device 130. A hole (not shown) for inserting a guide bar is formed in the main body 118. When the lever 119 is pushed up, the clamp 117 can be moved up and down along the guide bar 115, and when the lever 119 is pushed down, the clamp 117 is fixed to the guide bar 115. The clamp 117 is fixed to the guide bar 115 in a state where the multistage sieve unit 110 is completely assembled as shown in FIGS. 1 and 2, and the multistage sieve unit 110 is fixed to the mounting table 132 ( To be fixed later.

B. As shown in FIGS. 1 to 3, the connection member 120 is a substantially truncated conical cylindrical member, and is fixed to the lid body 116 so as to cover the opening of the lid body 116 of the multistage sieve unit 110. ing. A supply hose 160 is joined to the upper end of the connection member 120.

C. Vibration Device As shown in FIG. 1, the vibration device 130 mainly includes a main body 131, a placement table 132, and a guide bar 115.

  The main body 131 is provided with a mechanism (not shown) that vibrates the mounting table 132, a control unit (not shown), and the like.

  The mounting table 132 is a circular table. Then, vibration generated by the main body 131 is transmitted to the mounting table 132. Therefore, in a state where the multistage sieve unit 110 is fixed to the mounting table 132, vibration is transmitted to the multistage sieve unit 110.

  As shown in FIG. 1, the guide bar 115 extends upward from a placement table 132 (described later) of the vibration device 130. A lid 116 and a clamp 117 are inserted through the guide bar 115.

D. The discharge tube The discharge tube 140 is connected to the discharge tube 114 of the tray 113 with the discharge tube, and plays a role of guiding the discharged liquid to the discharge container 150.

E. Discharge container The discharge container 150 is a normal container.

F. Supply Hose The supply hose 160 is joined to the upper end of the connection member 120 as shown in FIG. The supply hose 160 is provided to supply additional solvent to the multistage sieve unit 110.

(2) Method of using wet classifier First, the multi-stage sieve unit 110 is assembled on the mounting table 132 of the vibration device 130. At this time, the lid 116 is not yet installed, and the upper part of the multistage sieve unit 110, that is, the upper part of the first sieve 111a is opened. Next, after putting the flat conductive particles obtained in the flat conductive particle manufacturing process into the first sieve 111a, the lid 116 is installed, and the multistage sieve unit 110 is fixed to the mounting table 132 by the clamp 117. To do. Subsequently, the vibration device 130 is started to vibrate the multistage sieve unit 110 to start the classification process. During the classification process, the solvent flowing into the discharge container 150 is observed, and when the solvent becomes transparent, the vibration device 130 is stopped to stop the classification process.

  During the classification process, additional solvent may be supplied to the multistage sieve unit 110 via the supply hose 160 as necessary.

3. Drying Step The flat conductive particles classified in the wet classification step are then dried by heating.

<Manufacture of conductive paste>
1. material

(1) Conductive particles Flat conductive particles obtained as described above are used.

(2) Binder resin The binder resin is not particularly limited, and examples thereof include various thermoplastic resins and thermosetting resins. Here, the “thermosetting resin” is a resin that forms and cures a three-dimensional network structure by heating or energy ray irradiation, and includes a curing agent, a curing accelerator, and the like. The thermosetting resin is preferably liquid at room temperature. Examples of such thermosetting resins include cyanate resins, epoxy resins, radical polymerizable acrylic resins, and maleimide resins. Hereinafter, each resin will be described in detail.

A. Cyanate resin Cyanate resin is a resin having —NCO groups in the molecule. The cyanate resin is not particularly limited. For example, 1,3-dicyanatobenzene, 1,4-dicyanatobenzene, 1,3,5-tricyanatobenzene, 1,3-dicyanatonaphthalene, 1,4- Dicyanatonaphthalene, 1,6-dicyanatonaphthalene, 1,8-dicyanatonaphthalene, 2,6-dicyanatonaphthalene, 2,7-dicyanatonaphthalene, 1,3,6-tricyanatonaphthalene, 4,4 ′ -Dicyanatobiphenyl, bis (4-cyanatophenyl) methane, bis (3,5-dimethyl-4-cyanatophenyl) methane, 2,2-bis (4-cyanatophenyl) propane, 2,2-bis (3,5-dibromo-4-cyanatophenyl) propane, bis (4-cyanatophenyl) ether, bis (4-cyanatophenyl) thioether Bis (4-cyanatophenyl) sulfone, tris (4-cyanatophenyl) phosphite, tris (4-cyanatophenyl) phosphate, and cyanates obtained by reacting a novolac resin with cyanogen halide. It is done. Moreover, the prepolymer which has a triazine ring formed by trimerizing the cyanate group of these polyfunctional cyanate resin can also be used. This prepolymer is obtained by polymerizing the above-mentioned polyfunctional cyanate resin monomer using, for example, an acid such as mineral acid or Lewis acid, a base such as sodium alcoholate or tertiary amine, or a salt such as sodium carbonate as a catalyst. Is obtained.

  As the cyanate resin curing accelerator, generally known ones can be used. The curing accelerator is not particularly limited. For example, metal salts such as zinc octylate, tin octylate, cobalt naphthenate, zinc naphthenate, and iron acetylacetone, and aluminum chloride, tin chloride, and zinc chloride. , Amines such as triethylamine and dimethylbenzylamine. These curing accelerators can be used alone or in combination. The cyanate resin can also be used by blending with an epoxy resin, an oxetane resin, an acrylic resin, or a maleimide resin.

B. Epoxy resin An epoxy resin is a compound having at least one glycidyl group in the molecule, but it is preferable that two or more glycidyl groups are contained in one molecule. This is because sufficient cured product properties cannot be exhibited by reaction with only a compound having only one glycidyl group. The compound containing two or more glycidyl groups in one molecule is not particularly limited. For example, bisphenol compounds such as bisphenol A, bisphenol F, and biphenol or derivatives thereof, hydrogenated bisphenol A, hydrogenated bisphenol F, and hydrogenated biphenol. Diols having an alicyclic structure such as cyclohexanediol, cyclohexanedimethanol, and shidilohexanediethanol or derivatives thereof, aliphatic diols such as butanediol, hexanediol, octanediol, nonanediol, decanediol, or derivatives thereof Epoxidized bifunctional, trihydroxyphenylmethane skeleton, trifunctional one having aminophenol skeleton, phenol novolac resin, cresol novolac resin, phenol aralkyl Resins, biphenyl aralkyl resins, those such polyfunctional epoxidized are mentioned naphthol aralkyl resin and the like. In addition, these compounds are preferably liquid at room temperature alone or as a mixture. This is because the conductive paste needs to be in a liquid state at room temperature. A reactive diluent can also be used. Such reactive diluents are not particularly limited, and examples thereof include monofunctional aromatic glycidyl ethers such as phenyl glycidyl ether and cresyl glycidyl ether, and aliphatic glycidyl ethers.

  The epoxy resin curing agent cures the epoxy resin. Such a curing agent is not particularly limited, and examples thereof include aliphatic amines, aromatic amines, dicyandiamide, dicarboxylic acid dihydrazide compounds, acid anhydrides, and phenol resins. The dihydrazide compound is not particularly limited, and examples thereof include carboxylic acid dihydrazides such as adipic acid dihydrazide, dodecanoic acid dihydrazide, isophthalic acid dihydrazide, and P-oxybenzoic acid dihydrazide. The acid anhydride is not particularly limited. For example, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, dodecenyl succinic anhydride, a reaction product of maleic anhydride and polybutadiene And a copolymer of maleic anhydride and styrene. A phenol resin is a compound having two or more phenolic hydroxyl groups in one molecule. In addition, when this phenol resin has only one phenolic hydroxyl group in one molecule, since it cannot take a crosslinked structure, sufficient hardened | cured material property cannot be obtained and it cannot be used. Although it can be used as long as the number of phenolic hydroxyl groups in one molecule is 2 or more, the number of phenolic hydroxyl groups in one molecule is preferably 2 to 5. When the number of phenolic hydroxyl groups in one molecule is more than 5, the molecular weight becomes too large, and as a result, the viscosity of the conductive paste becomes too high. The number of phenolic hydroxyl groups in one molecule is more preferably 2 or 3. Examples of such compounds include, but are not limited to, for example, bisphenol F, bisphenol A, bisphenol S, tetramethyl bisphenol A, tetramethyl bisphenol F, tetramethyl bisphenol S, dihydroxy diphenyl ether, dihydroxy benzophenone, tetramethyl biphenol, and ethylidene bisphenol. , Bisphenols such as methylethylidenebis (methylphenol), cyclohexylidenebisphenol, biphenol and derivatives thereof, trifunctional phenols such as tri (hydroxyphenyl) methane and tri (hydroxyphenyl) ethane and derivatives thereof, phenol novolac, cresol A compound obtained by reacting phenols such as novolak with formaldehyde. Trinuclear body like those and their derivatives of the main.

The curing accelerator for the epoxy resin is not particularly limited, and examples thereof include imidazoles, triphenylphosphine or tetraphenylphosphine salts, amine compounds such as diazabicycloundecene and salts thereof, and the like. Imidazole, 2-ethylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-C Imidazole compounds such as ₁₁ H ₂₃ -imidazole, adducts of 2-methylimidazole and 2,4-diamino-6-vinyltriazine are preferably used. Among these imidazole compounds, imidazole compounds having a melting point of 180 ° C. or higher are particularly preferable.

C. Radical polymerizable acrylic resin The radical polymerizable acrylic resin is not particularly limited, and examples thereof include a (meth) acrylic resin having an unsaturated double bond. The (meth) acrylic resin having an unsaturated double bond is not particularly limited. For example, a polyether, polyester, polycarbonate, poly (meth) acrylate, polybutadiene, butadiene acrylonitrile copolymer having a molecular weight of 500 to 10,000 is used. Those that are combined and have a (meth) acryl group are preferred.

  As the polyether, those in which a divalent organic group having 3 to 6 carbon atoms is repeated via an ether bond are preferable, and those having no aromatic ring are preferable. Such a polyether can be obtained by reaction of polyether polyol with (meth) acrylic acid or a derivative thereof.

  As polyester, the thing which the C3-C6 bivalent organic group repeated via the ester bond is preferable, and the thing which does not contain an aromatic ring is preferable. Such a polyester can be obtained by reacting a polyester polyol with (meth) acrylic acid or a derivative thereof.

  As a polycarbonate, what a C3-C6 bivalent organic group repeated via the carbonate bond is preferable, and what does not contain an aromatic ring is preferable. Such a polycarbonate can be obtained by a reaction between a polycarbonate polyol and (meth) acrylic acid or a derivative thereof.

  The poly (meth) acrylate is not particularly limited. For example, it is a copolymer of (meth) acrylic acid and (meth) acrylate, or a (meth) acrylate having a hydroxyl group and no polar group (meth). A copolymer with acrylate is preferred. Such a poly (meth) acrylate can be obtained by reaction with an acrylate having a hydroxyl group when it can react with a carboxy group, and (meth) acrylic when it can react with a hydroxyl group. It can be obtained by reaction with an acid or a derivative thereof.

  The polybutadiene can be obtained, for example, by a reaction between a polybutadiene having a carboxy group and a (meth) acrylate having a hydroxyl group, or a reaction between a polybutadiene having a hydroxyl group and (meth) acrylic acid or a derivative thereof. It can also be obtained by a reaction between polybutadiene to which an acid has been added and (meth) acrylate having a hydroxyl group.

  The butadiene acrylonitrile copolymer can be obtained by a reaction between a butadiene acrylonitrile copolymer having a carboxy group and a (meth) acrylate having a hydroxyl group.

  The compound shown below can also be added as needed. For example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxy Butyl (meth) acrylate, 1,2-cyclohexanediol mono (meth) acrylate, 1,3-cyclohexanediol mono (meth) acrylate, 1,4-cyclohexanediol mono (meth) acrylate, 1,2-cyclohexanedimethanol mono (Meth) acrylate, 1,3-cyclohexanedimethanol mono (meth) acrylate, 1,4-cyclohexanedimethanol mono (meth) acrylate, 1,2-cyclohexanediethanol mono (meth) acrylate 1,3-cyclohexanediethanol mono (meth) acrylate, 1,4-cyclohexanediethanol mono (meth) acrylate, glycerin mono (meth) acrylate, glycerin di (meth) acrylate, trimethylolpropane mono (meth) acrylate, tri (Meth) acrylate having a hydroxyl group such as methylolpropane di (meth) acrylate, pentaerythritol mono (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, neopentyl glycol mono (meth) acrylate, And (meth) acrylate having a carboxy group obtained by reacting a (meth) acrylate having a hydroxyl group with a dicarboxylic acid or a derivative thereof. In addition, although it does not specifically limit as dicarboxylic acid which can be used here, For example, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid , Fumaric acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid and derivatives thereof.

  In addition to the above, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tertiary butyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) Acrylate, tridecyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, isoamyl (meth) acrylate, isostearyl (meth) acrylate, behenyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, other alkyls (Meth) acrylate, cyclohexyl (meth) acrylate, tertiary butylcyclohexyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, benzyl (meth) acrylate Phenoxyethyl (meth) acrylate, isobornyl (meth) acrylate, glycidyl (meth) acrylate, trimethylolpropane tri (meth) acrylate, zinc mono (meth) acrylate, zinc di (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (Meth) acrylate, neopentyl glycol (meth) acrylate, trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, 2,2,3,3,4,4-hexa Fluorobutyl (meth) acrylate, perfluorooctyl (meth) acrylate, perfluorooctylethyl (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, tetramethylene glycol di (meth) acrylate, methoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxypolyalkylene glycol mono (meth) Acrylate, Octoxy polyalkylene glycol mono (meth) acrylate, Lauroxy polyalkylene glycol mono (meth) acrylate, Stearoxy polyalkylene glycol mono (meth) acrylate, Allyloxy poly Alkylene glycol mono (meth) acrylate, nonylphenoxy polyalkylene glycol mono (meth) acrylate, N, N′-methylenebis (meth) acrylamide, N, N′-ethylenebis (meth) acrylamide, 1,2-di (meth) Acrylamide ethylene glycol, di (meth) acryloyloxymethyl tricyclodecane, N- (meth) acryloyloxyethyl maleimide, N- (meth) acryloyloxyethyl hexahydrophthalimide, N- (meth) acryloyloxyethyl phthalimide N-vinyl-2-pyrrolidone, styrene derivatives, α-methylstyrene derivatives and the like can also be used.

  As the polymerization initiator, a thermal radical polymerization initiator is preferably used. The polymerization initiator is not particularly limited as long as it can be used as a thermal radical polymerization initiator, but a rapid heating test (decomposition start when a sample 1 g is placed on an electric heating plate and heated at 4 ° C./min. The decomposition start temperature in the test for measuring temperature is preferably 40 to 140 ° C. This is because when the decomposition start temperature is in this range, the normal temperature storage stability and curing time of the conductive paste can be maintained well. The thermal radical polymerization initiator that satisfies this condition is not particularly limited. 3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis (t-hexylperoxy) 3,3,5-trimethylcyclohexane, 1,1-bis ( t-butylperoxy) cyclohexane, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, 1,1-bis (t-butylperoxy) cyclododecane, n-butyl4,4 -Bis (t-butylperoxy) valerate, 2,2-bis t-butylperoxy) butane, 1,1-bis (t-butylperoxy) -2-methylcyclohexane, t-butyl hydroperoxide, P-menthane hydroperoxide, 1,1,3,3-tetramethyl Butyl hydroperoxide, t-hexyl hydroperoxide, dicumyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, α, α'-bis (t-butylperoxy) Diisopropylbenzene, t-butylcumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3, isobutyryl peroxide, 3,5,5 -Trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide Cinnamic acid peroxide, m-toluoyl peroxide, benzoyl peroxide, diisopropyl peroxydicarbonate, bis (4-tert-butylcyclohexyl) peroxydicarbonate, di-3-methoxybutylperoxydicarbonate, di- 2-ethylhexyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, di (3-methyl-3-methoxybutyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, α, α′-bis (neodecanoylperoxy) diisopropylbenzene, cumylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylper Oxyneodecanoe T-hexylperoxyneodecanoate, t-butylperoxyneodecanoate, t-hexylperoxypivalate, t-butylperoxypivalate, 2,5-dimethyl-2,5-bis ( 2-ethylhexanoylperoxy) hexane, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t- Hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, t-butylperoxymaleic acid, t-butylperoxylaurate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxyisopropyl Mono-carbonate, t-butylperoxy-2-ethylhexyl monocarbonate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, t-butylperoxyacetate, t-hexylperoxybenzoate, t-butyl Peroxy-m-toluoylbenzoate, t-butylperoxybenzoate, bis (t-butylperoxy) isophthalate, t-butylperoxyallyl monocarbonate, 3,3 ′, 4,4′-tetra (t- Butyl peroxycarbonyl) benzophenone and the like. These thermal radical polymerization initiators may be used alone or in combination of two or more for controlling curability.

D. Maleimide resin Maleimide resin is a compound containing one or more maleimide groups in one molecule. The maleimide resin is not particularly limited. For example, N, N ′-(4,4′-diphenylmethane) bismaleimide, bis (3-ethyl-5-methyl-4-maleimidophenyl) methane, 2,2-bis And bismaleimide resins such as [4- (4-maleimidophenoxy) phenyl] propane. More preferred maleimide resins include compounds obtained by reaction of dimer acid diamine and maleic anhydride, and compounds obtained by reaction of maleimidated amino acids such as maleimide acetic acid and maleimide caproic acid with polyols. The maleimidated amino acid can be obtained by reacting maleic anhydride with aminoacetic acid or aminocaproic acid. As the polyol, polyether polyol, polyester polyol, polycarbonate polyol, and poly (meth) acrylate polyol are preferable, and those not containing an aromatic ring are particularly preferable. Since the maleimide group can react with an allyl group, it can also be used in combination with an allyl ester resin. As the allyl ester resin, aliphatic resins are preferable, and among them, compounds obtained by transesterification of cyclohexane diallyl ester and aliphatic polyol are particularly preferable. Moreover, this maleimide resin can also be used in combination with a cyanate resin, an epoxy resin, or an acrylic resin.

(3) Others Various additives and solvents may be used as necessary.
Although it does not specifically limit as an additive, For example, Silane coupling agents, such as an epoxy silane, a mercapto silane, an amino silane, an alkyl silane, a ureido silane, a vinyl silane, a titanate coupling agent, an aluminum coupling agent, an aluminum / zirconium coupling agent Coupling agents such as carbon black, colorants such as carbon black, low stress components such as silicone oil and silicone rubber, inorganic ion exchangers such as hydrotalcite, antifoaming agents, surfactants, various polymerization inhibitors, antioxidants Various additives, such as an agent, are mentioned.

  It does not specifically limit as a solvent, What is necessary is just to dissolve the above-mentioned resin and to have moderate volatility.

2. Method for Producing Conductive Paste The conductive paste can be produced, for example, by premixing the above-described components and then kneading using a three roll and further degassing under vacuum.

<Manufacture of semiconductor devices>
The semiconductor device can be manufactured using a known method. For example, after applying the above-mentioned conductive paste to a predetermined part of a lead frame with a commercially available die bonder, a chip is mounted on the part and the conductive paste is heated and cured. Then, after wire bonding is performed, an epoxy resin is transfer molded to manufacture a semiconductor device. In addition, after flip chip bonding, conductive paste is dispensed on the back side of a chip such as flip chip BGA that is sealed with an underfill material, and heat dissipating parts such as heat spreaders and lids are mounted on the back side of the chip to heat and cure the conductive paste. It is also possible to create a semiconductor device.

<Example>
Hereinafter, the manufacturing method of the flat electroconductive particle which concerns on embodiment of this invention is demonstrated in detail by showing an Example.

(1) Manufacturing process of flat electroconductive particle The stirring ball mill by which the stirring blade was arrange | positioned in the cylindrical container was prepared. In this example, the radius of the cylindrical container was 15 cm and the height was 30 cm. The radius of the stirring blade was 14 cm.

10 kg of reduced silver particles (silver particles obtained by chemically reducing silver nitrate) and 30 kg of titanium balls were put into a cylindrical container of a stirring ball mill. In this example, the average particle diameter of the reduced silver particles was 5 μm, and the specific surface area was 0.2 m ² / g. The diameter of the titanium ball was 0.8 mm. Further, 8 kg of ethanol, 0.1 kg of methyl oleate and 0.1 kg of methyl palmitate were charged into the cylindrical container. Thereafter, the rotation speed of the stirring blade was set to 500 rpm, and the stirring ball mill was started to start flaking of the reduced silver particles. After the stirring ball mill was operated for 2 hours, the rotation of the stirring blade was stopped, and the slurry-like flat conductive particles were taken out from the cylindrical container.

(2) Classifying Step The slurry-like flat conductive particles obtained in the above manufacturing process were wet-classified using the wet-classifying device 100 shown in FIGS. In this embodiment, the mesh of the mesh Ma of the first sieve (uppermost sieve) 111a is 38 μm, the mesh of the mesh Mb of the second sieve (intermediate sieve) 111b is 20 μm, and the third sieve (Lowest sieve) The mesh Mc of the 111c was 10 μm.

(3) Drying step The flat conductive particles classified in the wet classification step were dried by heating to obtain the target flat conductive particles.

<Features>
In the method for producing flat conductive particles according to the embodiment of the present invention, first, conductive particles produced by a method such as a mechanical pulverization method, a chemical reduction method, an electrolysis method, or an atomization method are used as an attritor or stamp. It is flattened in a wet environment by a pulverizer such as a mill, a ball mill, a bead mill, or a jet mill. For this reason, in the manufacturing method of this flat electroconductive particle, taking out of the flat electroconductive particle can be performed easily. Thereafter, the flattened conductive particles are subjected to wet sieving and classification using a wet classifier without being dried. When wet sieving classification is performed, the flat conductive particles can be subjected to precise classification at a higher speed than dry sieving classification. For this reason, in the manufacturing method of flat electroconductive particle, flat electroconductive particle can be precisely classified at comparatively high speed.

  In addition, since the flat conductive particles obtained in this way have a very narrow particle size distribution, there is a sufficient suppression of the possibility of causing problems such as clogging of syringes when used for conductive pastes. can do.

<Modification>
(A)
In the method for producing flat conductive particles according to the previous embodiment, in the flat conductive particle production process, the conductive particles were flattened in a wet environment, but the conductive particles were flattened in a dry environment. It doesn't matter. In such a case, before performing wet sieving classification, it is required to add the above-mentioned solvent to the flattened conductive particles to make the flat conductive particles into a slurry.

(B)
Although not particularly mentioned in the previous embodiment, a fatty acid ester compound may be used as a lubricant when the conductive particles are flattened in the flat conductive particle production process.

  The fatty acid ester compound is not particularly limited. For example, a fatty acid alkyl ester compound having 10 to 30 carbon atoms is preferable, and a fatty acid alkyl ester compound having 14 to 20 carbon atoms is more preferable. . Specific fatty acid ester compounds are not particularly limited. For example, methyl caprate, ethyl caprate, butyl caprate, other alkyl esters of capric acid, methyl laurate, ethyl laurate, butyl laurate, lauric acid Other alkyl esters, methyl myristate, ethyl myristate, butyl myristate, other alkyl esters of myristic acid, methyl pentadecylate, ethyl pentadecylate, butyl pentadecylate, other alkyl esters of pentadecyl acid, methyl palmitate, ethyl palmitate, Butyl palmitate, other alkyl esters of palmitic acid, methyl margarate, ethyl margarate, butyl margarate, other alkyl esters of margaric acid, methyl stearate, Ethyl stearate, butyl stearate, other alkyl esters of stearic acid, methyl arachidate, ethyl arachidate, butyl arachidate, other alkyl esters of arachidic acid, methyl behenate, ethyl behenate, butyl behenate, other behenic acids Alkyl ester, methyl lignocerate, ethyl lignocerate, butyl lignocerate, other alkyl esters of lignoceric acid, methyl serotenate, ethyl serotic acid, butyl serotic acid, other alkyl esters of serotic acid, methyl montanate, ethyl montanate, montan Alkyl esters of saturated fatty acids such as butyl acid, other alkyl esters of montanic acid, methyl melicinate, ethyl melicinate, butyl melicinate, other alkyl esters of melicic acid Compounds, methyl myristoleate, ethyl myristate, butyl myristoleate, other alkyl esters of myristoleic acid, methyl palmitate, ethyl palmitoleate, butyl palmitoleate, other alkyl esters of palmitoleic acid, olein Methyl acid, ethyl oleate, butyl oleate, other alkyl esters of oleic acid, methyl elaidate, ethyl elaidate, butyl elaidate, other alkyl esters of elaidic acid, methyl vaccenate, ethyl vaccenate, butyl vacceate, vacsen Other alkyl esters of acids, methyl gadrate acid, ethyl gadrate acid, butyl gadrate acid, other alkyl esters of gadrate acid, methyl erucate, ethyl erucate, elca Butyl acid, other alkyl esters of erucic acid, methyl nervonic acid, ethyl nervonic acid, butyl nervonic acid, other alkyl esters of nervonic acid, methyl linoleate, ethyl linoleate, butyl linoleate, other alkyl esters of linoleic acid, linolenic acid Methyl, ethyl linolenate, butyl linolenate, other alkyl esters of linolenic acid, methyl eleostearate, ethyl eleostearate, butyl eleostearate, other alkyl esters of eleostearic acid, methyl stearidonic acid, stearidonic acid Ethyl, butyl stearidonic acid, other alkyl esters of stearidonic acid, methyl arachidonic acid, ethyl arachidonic acid, butyl arachidonic acid, other alkyl esters of arachidonic acid, methyl eicosapentaenoate Ethyl eicosapentaenoate, butyl eicosapentaenoate, other alkyl esters of eicosapentaenoic acid, methyl sardate, ethyl sardate, butyl sardate, other alkyl esters of sardate, methyl docosahexaenoate, ethyl docosahexaenoate, docosahexaenoic acid, docosahexaene Examples include alkyl esters of unsaturated fatty acids of other alkyl esters of acids. In addition, these fatty acid ester compounds may be used independently and may be used together.

  Among these fatty acid ester compounds, fatty acid methyl ester compounds such as at least one fatty acid ester compound selected from the group consisting of methyl palmitate, methyl palmitate and methyl oleate are preferred. Moreover, the combined use of at least one fatty acid ester compound selected from the group consisting of methyl palmitate, methyl palmitate and methyl oleate and a methyl ester compound of other saturated fatty acids is also preferred. Further, a methyl ester compound of an unsaturated fatty acid, for example, at least one fatty acid ester compound selected from the group consisting of methyl palmitate and methyl oleate is more preferable. In addition, a combination of at least one unsaturated fatty acid ester compound selected from the group consisting of methyl palmitate and methyl oleate and a methyl ester compound of a saturated fatty acid is more preferable. These fatty acid ester compounds may be used in combination with fatty acids, fatty acid salts, higher aliphatic alcohols, esters of higher aliphatic alcohols, higher aliphatic amines, higher aliphatic amides, polyethylene waxes, and the like.

The fatty acid ester compound is preferably used in an amount of 0.005 g to 0.5 g per 1 m ² of the surface area of the conductive particles. This is because, if the concentration of the fatty acid ester compound is within this range, the conductive particles do not aggregate in the flat conductive particle production process, and conductive particles having good conductivity can be obtained. In addition, when the concentration of the fatty acid ester compound is less than 0.005 g / m ² , aggregation tends to occur during the production process of the flat conductive particles, and when the concentration of the fatty acid ester compound is higher than this, the obtained conductive particles This is because if the remaining fatty acid ester compound exceeds 0.5 g / m ² , the conductive particles may be deteriorated in conductivity when the conductive particles are used as a conductive paste.

(C)
In the method for producing flat conductive particles according to the previous embodiment, the same solvent was used in both the flat conductive particle production step and the wet classification step, but the flat conductive particle production step and the wet classification were used. A different solvent may be used in the process. In such a case, the conductive particles are once dried after the flat conductive particle manufacturing process, and then the dried conductive particles are added to a solvent different from the solvent in the flat conductive particle manufacturing process.

(D)
In the method for producing flat conductive particles according to the previous embodiment, the wet classification apparatus shown in FIGS. 1 to 3 was employed in the wet classification step. However, as long as the gist of the present invention is not impaired, other commercially available wet types are used. A classification device may be adopted. In addition, the multistage sieve unit 110 of the wet classifier 100 according to the previous embodiment has a three-stage configuration, but the number of stages is not particularly limited, and may be one or two. Or four or more stages.

(E)
Although not particularly mentioned in the previous embodiment, a brush, a ball, or the like may be used as a measure for preventing clogging of the sieve in the wet classification process.

(F)
In the method for producing flat conductive particles according to the previous embodiment, the multistage sieve unit 110 is vibrated in the wet classification process, but the multistage sieve unit 110 may be moved in the plane.

100 wet classifier 110 multi-stage sieve unit 111a, 111b, 111c sieve 112a, 112b intermediate ring 113 tray 114 with discharge pipe discharge pipe 115 guide bar 116 lid 117 clamp 118 main body 119 lever 120 connecting member 130 vibration device 131 main body 132 Placement table 140 Discharge tube 150 Discharge container 160 Supply hose Fa, Fb, Fc Frame Ma, Mb, Mc Mesh P Air hole Or O-ring

Claims (5)

A flat conductive particle production process for producing flat conductive particles;
A method for producing flat conductive particles, comprising a wet classification step of sieving and classifying the flat conductive particles by a wet method. The method for producing flat conductive particles according to claim 1, wherein in the flat conductive particle manufacturing step, the flat conductive particles are manufactured by a wet process. In the wet classification step, the slurry of the flat conductive particles whose concentration is adjusted so that the flat conductive particles are in a range of 0.1 wt% or more and 50 wt% or less with respect to the liquid medium. The manufacturing method of the flat electroconductive particle of Claim 1 or 2 supplied to a sieve. The flat electroconductive particle manufactured by the manufacturing method of the flat electroconductive particle in any one of Claim 1 to 3. The flat conductive particles according to claim 4,
A resin composition containing a resin.