JP7062555B2 - Coated particles - Google Patents

Description

The present invention relates to coated particles in which conductive particles are coated on an insulating layer.

The conductive particles in which a metal such as nickel or gold is formed on the surface of the resin particles are used as a conductive material such as a conductive adhesive, an anisotropic conductive film, and an anisotropic conductive adhesive.
In recent years, with the further miniaturization of electronic devices, the circuit width and pitch of electronic circuits have become smaller and smaller. Along with this, as the conductive particles used in the above-mentioned conductive adhesives, anisotropic conductive films, anisotropic conductive adhesives and the like, those having a small particle size are required. When conductive particles having such a small particle size are used, the blending amount of the conductive particles must be increased in order to improve the connectivity. However, if the blending amount of the conductive particles is increased, a short circuit occurs due to conduction in an unintended direction, that is, conduction in a direction different from that between the counter electrodes, and it is difficult to obtain insulation in that direction. ing. In order to solve this problem, insulating layer-coated conductive particles are used in which the surface of the conductive particles is coated with an insulating substance to prevent the metal layers of the conductive particles from coming into contact with each other. In the coated particles having such a structure, the insulating fine particles are usually melted, deformed or peeled off by crimping the coated particles between the electrodes to expose the metal surface of the metal-coated particles, thereby conducting conduction between the electrodes. Is possible and connectivity is obtained.

For example, Non-Patent Document 1 describes coated particles in which the surface of conductive particles is coated with insulating fine particles having a triethylphosphonium group.

Proceedings of the 66th Polymer Conference Vol.66, No.2, P 60

Insulating fine particles having a phosphonium group as described in Non-Patent Document 1 have better adhesion to conductive particles than insulating fine particles having a positive charge such as an ammonium group conventionally used in the present technical field. expensive.
On the other hand, conductive particles having a metal film such as nickel are required to sufficiently prevent oxidation of the metal film. If the metal film is oxidized, the conductivity may decrease over time.
Further, in the case of coated particles made of conductive particles coated with insulating fine particles, it is also required that the surface of the metal-coated particles can be easily densely coated with the insulating fine particles. If the surface of the metal-coated particles is not sufficiently densely coated with the insulating fine particles, a part of the surface of the conductive particles is not covered, and if the conductive particles are close to each other inside the anisotropic conductive film, the film is formed. There is a possibility of electrical contact in the plane direction of. In addition, there is a possibility that the insulating properties cannot be ensured even if the insulating fine particles are slightly peeled off from the surface of the metal-coated particles during the manufacturing of the conductive material or the thermocompression bonding of the device manufacturing.
However, the conventional coated particles coated with the insulating fine particles described in Non-Patent Document 1 are sufficient in that they both prevent oxidation of the metal film and have a dense covering property of the insulating fine particles on the surface of the metal-coated particles. It wasn't.

Therefore, an object of the present invention is to provide insulating layer-coated conductive particles that can solve the problems of conventional coated particles.

As a result of diligent research to solve the above-mentioned problems, the present inventors have made conductive particles when using insulating fine particles containing a phosphonium group having an alkyl chain having a specific carbon number as an insulating substance. On the other hand, they have found that they can effectively prevent the oxidation of the metal film while obtaining the same adhesion as the conventional insulating fine particles containing a triethylphosphonium group, and completed the present invention.

（式中、Ｒはそれぞれ独立に、炭素数４以上１０以下のアルキル基である）。 That is, the present invention has a conductive metal-coated particles having a metal film formed on the surface of the core material and an insulating layer made of a polymer that coats the metal-coated particles, and the insulating layer has the following formula (1). It provides coated particles having a phosphonium group represented by.

(In the formula, R is an alkyl group having 4 or more and 10 or less carbon atoms independently).

The coated particles of the present invention are those in which oxidation of the metal film is prevented and deterioration of conductivity with time is suppressed. Further, when the insulating layer is an insulating fine particle or a continuous film obtained by melting or dissolving the insulating fine particles, it is easy to densely cover the surface of the conductive metal-coated particles with the insulating layer, and the insulating layer has stable insulating properties.
Such coated particles of the present invention have high connection reliability.

FIG. 1 is a photograph of the coated particles obtained in Example 4 observed by SEM. FIG. 2 is a photograph of the coated particles obtained in Example 7 observed by SEM. FIG. 3 is a photograph of the coated particles obtained in Example 8 observed by SEM.

Hereinafter, the present invention will be described based on a preferred embodiment.
The coated particles of the present embodiment have a conductive metal-coated particles having a metal film formed on the surface of the core material and an insulating layer made of a polymer that coats the metal-coated particles, and the insulating layer is of the formula ( It has a phosphonium group represented by 1).

As the conductive metal-coated particles (hereinafter, also referred to as “conductive particles”), known ones conventionally used for conductive adhesives, anisotropic conductive films, and anisotropic conductive adhesives can be used. ..
The core material of the conductive particles is in the form of particles, and can be used without particular limitation whether it is an inorganic substance or an organic substance. Examples of the inorganic core particles include metal particles such as gold, silver, copper, nickel, palladium, and solder, alloys, glass, ceramics, silica, metal or non-metal oxides (including hydrous), and aluminosilicates. Examples thereof include metal silicates, metal carbides, metal nitrides, metal carbonates, metal sulfates, metal phosphates, metal sulfides, metal acid salts, metal halides and carbons. On the other hand, examples of the organic core particles include thermoplastics such as natural fibers, natural resins, polyethylene, polypropylene, polyvinyl chloride, polystyrene, polybutene, polyamide, polyacrylic acid ester, polyacrylic nitrile, polyacetal, ionomer, and polyester. Examples thereof include resins, alkyd resins, phenol resins, urea resins, benzoguanamine resins, melamine resins, xylene resins, silicone resins, epoxy resins, diallyl phthalate resins and the like. These may be used alone or in combination of two or more. Among these, the core material particles made of a resin material are preferable in that the specific gravity is smaller than that of the core material particles made of metal, the sedimentation is difficult, the dispersion stability is excellent, and the electrical connection is easily maintained due to the elasticity of the resin. ..

When an organic substance is used as the core material particles, the fact that the core material particles do not have a glass transition temperature or the glass transition temperature is more than 100 ° C. makes it easy to maintain the shape of the core material particles in the anisotropic conductive connection step and the metal. It is preferable because it is easy to maintain the shape of the core material particles in the step of forming the film. Further, when the core material particles have a glass transition temperature, the glass transition temperature is 200 ° C. or less, which means that the conductive particles tend to soften in the anisotropic conductive connection and the contact area becomes large, so that conduction can be easily obtained. It is preferable from. From this viewpoint, when the core material particles have a glass transition temperature, the glass transition temperature is more preferably more than 100 ° C. and 180 ° C. or lower, and particularly preferably more than 100 ° C. and 160 ° C. or lower. The glass transition temperature can be measured by the method described in Examples described later.

When an organic substance is used as the core material particles and the organic substance is a highly crosslinked resin, the glass transition temperature is hardly observed even if the measurement is attempted to 200 ° C. by the method described in the following Examples. In the present specification, such particles are also referred to as particles having no glass transition point, and in the present invention, such core material particles may be used. The core particle material having no such glass transition temperature can be obtained by copolymerizing the monomer constituting the organic substance exemplified above with a crosslinkable monomer in combination. Examples of the crosslinkable monomer include tetramethylene di (meth) acrylate, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, ethylene oxide di (meth) acrylate, and tetraethylene oxide. (Meta) acrylate, 1,6-hexanedi (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, trimeterol propantri (meth) acrylate, tetramethylol methanedi ( Meta) acrylate, tetramethylol methanetri (meth) acrylate, tetramethylol methanetetra (meth) acrylate, tetramethylol propanetetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol di (meth) acrylate, glycerol tridi (meth) Polyfunctional (meth) acrylates such as meth) acrylates, polyfunctional vinyl monomers such as divinylbenzene and divinyltoluene, vinyltrimethoxysilane, trimethoxysilylstyrene, γ- (meth) acryloxypropyltrimethoxysilane, etc. Examples thereof include monomers such as silane-containing monomers, triallyl isocyanurate, diallyl phthalate, diallyl acrylamide, and diallyl ether. Especially in the field of COG (Chip on Glass), it is crosslinked with the polyfunctional (meth) acrylate, the polyfunctional vinyl monomer, the silane-containing monomer, triallyl isocyanurate, diallyl phthalate, diallyl acrylamide or diallyl ether. A lot of core material particles made of hard organic material are used.

There is no particular limitation on the shape of the core material particles. Generally, the core material particles are spherical. However, the core material particles may have a shape other than a spherical shape, for example, a fibrous shape, a hollow shape, a plate shape, or a needle shape, and may have a large number of protrusions on the surface thereof or an amorphous shape. In the present invention, spherical core material particles are preferable in terms of excellent filling property and easy coating with metal.
The shape of the conductive particles depends on the shape of the core material particles, but is not particularly limited. For example, it may be fibrous, hollow, plate-shaped or needle-shaped, and may have protrusions on its surface or may be amorphous. In the present invention, a spherical shape or a shape having protrusions on the surface is preferable in terms of excellent filling property and connectivity.
When the conductive particles have a shape having protrusions on the surface, it is preferable to have a plurality of protrusions on the surface, and it is more preferable to have a plurality of protrusions on a spherical surface. When the conductive particles have a shape having a plurality of protrusions, the core material particles may have a plurality of protrusions, or the core material particles do not have the protrusions and the metal film has a plurality of protrusions. It may be. Preferably, the core material particles do not have protrusions and the metal film has a plurality of protrusions. By having the protrusions on the surface of the conductive particles, when the conductive particles are compressed by the electrodes at the time of mounting, the protrusions can effectively push away the insulating layer. The height H of the protrusions of the conductive particles is such that H / L is 0.1 or more when the thickness of the insulating layer is L, so that the insulating layer is eliminated at the time of mounting to ensure electrical conduction. It is preferable from the viewpoint of making it simple. Further, it is preferable that the H / L is 10 or less from the viewpoint of obtaining the filling property and the insulating property in a direction different from that of the counter electrode. From these points, it is even more preferable that the H / L is 0.2 or more and 5 or less. In these preferable ranges, the thickness L refers to the average particle diameter of the insulating fine particles when the insulating layer is the insulating fine particles.

The height H of the protrusions is preferably 20 nm or more on average, particularly preferably 50 nm or more. The number of protrusions depends on the particle size of the conductive particles, but it is preferable that the number of protrusions is 1 to 20000, particularly 5 to 5000, per particle from the viewpoint of further improving the conductivity of the conductive particles. .. The aspect ratio of the protrusions is preferably 0.3 or more, more preferably 0.5 or more. A large aspect ratio of the protrusions is advantageous because it can easily break through the oxide film formed on the electrode surface. The aspect ratio is a ratio between the height H of the protrusion and the length D of the base of the protrusion, that is, a value defined by H / D. The height H of the protrusion and the length D of the base of the protrusion are average values measured for 20 different particles observed by an electron microscope, and the aspect ratio of the protrusion is 20 different values observed by an electron microscope. The aspect ratio of the particles was calculated and the average value was calculated. The length D of the base is the length of the base of the protrusion along the surface of the conductive particles in the electron microscope image.

The aspect ratio of the protrusions formed on the surface of the conductive particles is as described above, but the length D of the base of the protrusions itself is preferably 5 to 500 nm, particularly preferably 10 to 400 nm, and the height H of the protrusions. It is preferably 20 to 500 nm, particularly preferably 50 to 400 nm.

The metal film in the conductive particles has conductivity, and the constituent metals include, for example, gold, platinum, silver, copper, iron, zinc, nickel, tin, lead, antimony, bismuth, cobalt, indium, and the like. Examples thereof include metals such as titanium, antimony, bismuth, germanium, aluminum, chromium, palladium, tungsten and molybdenum, alloys thereof, and metal compounds such as ITO and solder. Of these, gold, silver, copper, nickel, palladium or solder are preferable because they have low resistance, and nickel, gold, nickel alloys or gold alloys are particularly preferably used because they have high bonding properties with phosphonium groups in insulating fine particles. .. Further, nickel, nickel alloy, iron, zinc, tin, lead, cobalt, titanium and aluminum are preferable because the antioxidant effect according to the present invention can be easily obtained. From these points, nickel or nickel alloy is most preferable. The metal in the conductive particles may be used alone or in combination of two or more.

The metal film may have a single-layer structure or a laminated structure composed of a plurality of layers. In the case of a laminated structure consisting of a plurality of layers, it is preferable that the outermost layer is made of nickel, gold, a nickel alloy or a gold alloy because of the high bondability with the phosphonium group in the insulating fine particles, and nickel and nickel alloys. , Iron, zinc, tin, lead, cobalt, titanium, and aluminum are preferable because the antioxidant effect according to the present invention can be easily obtained. From these points, nickel or nickel alloy is most preferable.

The outer surface of the metal film may be surface-treated to prevent corrosion and oxidation of the metal film. This surface treatment can be performed by using a known surface treatment agent. Examples of the surface treatment agent include phosphoric acid-based compounds, chromic acid-based compounds, triazole-based compounds, imidazole-based compounds, and thiazole-based compounds.

Further, the metal film may cover the entire surface of the core material particles, or may cover only a part thereof. When only a part of the surface of the core material particles is covered, the coated portions may be continuous, for example, may be discontinuously covered in an island shape. The thickness of the metal film is preferably 0.001 μm or more and 2 μm or less.

As a method for forming a metal film on the surface of the core material particles, a dry method using a vapor deposition method, a sputtering method, a mechanochemical method, a hybridization method, etc., an electrolytic plating method, a wet method using an electroless plating method, etc. are used. Can be mentioned. Further, a metal film may be formed on the surface of the core material particles by combining these methods.

The average particle size of the conductive particles is preferably 0.1 μm or more and 50 μm or less, and more preferably 1 μm or more and 30 μm or less. When the average particle diameter of the conductive particles is within the above range, the obtained coated particles do not cause a short circuit in a direction different from that between the counter electrodes, and it is easy to secure conduction between the counter electrodes. In the present invention, the average particle size of the conductive particles is an average value of the particle size measured by using a scanning electron microscope (SEM). When the conductive particles are spherical in the scanning electron microscope image, the particle diameter measured by using SEM is the diameter of the circular conductive particle image. When the conductive particles are not spherical, the particle diameter measured by SEM means the largest length (maximum length) of the line segments traversing the image of the conductive particles. This also applies to the average particle size of the insulating fine particles described later. However, when the conductive particles have protrusions, the above-mentioned maximum length of the portion other than the protrusions is taken as the average particle diameter.
Specifically, the average particle size of the conductive particles is measured by the method described in Examples.

As represented by the formula (1), the insulating layer covering the conductive particles has a trialkylphosphonium group composed of an alkyl group having 4 to 10 carbon atoms. A trialkylphosphonium group consisting of an alkyl group having 4 to 10 carbon atoms is more hydrophobic than a triethylphosphonium group. The present inventor speculates that this is one of the reasons why the metal film of the conductive particles is less likely to be oxidized in the present invention as compared with the conventional coated particles in which the insulating layer has a triethylphosphonium group.

Examples of the insulating layer in the present invention include those in which a plurality of insulating fine particles containing a compound having a phosphonium group are arranged in a layer, or an insulating continuous film containing a compound having a phosphonium group.
First, a case where the insulating layer is composed of insulating fine particles and the fine particles contain a compound having a phosphonium group will be described. In this case, the insulating fine particles are melted, deformed, peeled off, or moved on the surface of the conductive particles by thermocompression bonding the coated particles between the electrodes, so that the metal surface of the conductive particles in the thermocompression bonded portion is exposed. This enables continuity between the electrodes and provides connectivity. On the other hand, since the surface portion of the coated particles facing a direction other than the thermocompression bonding direction is generally maintained in a state of being coated on the surface of the conductive particles by the insulating fine particles, conduction in a direction other than the thermocompression bonding direction is prevented.

The insulating fine particles preferably have a phosphonium group represented by the formula (1) on the surface thereof. In the present specification, if the insulating fine particles have a phosphonium group represented by the formula (1) and it can be confirmed by observation with a scanning electron microscope that the insulating fine particles are attached to the surface of the conductive particles, "insulation". It corresponds to "the sex fine particles have a phosphonium group represented by the formula (1) on the surface".

The shape of the insulating fine particles is not particularly limited and may be spherical or non-spherical. Examples of the shape other than the spherical shape include a fibrous shape, a hollow shape, a plate shape, and a needle shape. Further, the insulating fine particles may have a large number of protrusions on the surface thereof or may have an amorphous shape. Spherical insulating fine particles are preferable in terms of adhesion to conductive particles and ease of synthesis.

It is preferable that the phosphonium group represented by the formula (1) in the insulating fine particles forms a part of the chemical structure of the substance as a part of the substance constituting the insulating fine particles. In the insulating fine particles, the phosphonium group is preferably contained in at least one structure of the structural unit of the polymer constituting the insulating fine particles. The phosphonium group represented by the formula (1) is preferably chemically bonded to the polymer constituting the insulating fine particles, and more preferably bonded to the side chain of the polymer.

Examples of the alkyl group represented by R include linear, branched and cyclic groups. Examples of the linear group include n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group and n-decyl group.

The branched alkyl group represented by R includes an isobutyl group, an s-butyl group, a t-butyl group, an isopentyl group, a neopentyl group, a 3-pentyl group, an s-pentyl group, a t-pentyl group, and an isohexyl group. , S-hexyl group, t-hexyl group, ethylhexyl group and the like.

Examples of the cyclic alkyl group represented by R include cycloalkyl groups such as cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group and cyclooctadecyl group.

R is preferably a linear alkyl group from the viewpoint that the insulating fine particles are close to and easily adhere to the conductive particles.
Further, the number of carbon atoms of the alkyl group represented by R is 4 or more and 10 or less in order to make the dense filling property of the conductive particles into the insulating fine particles and the hydrophobicity of the insulating fine particles appropriate. It is more preferable that the number of carbon atoms is 4 or more and 8 or less.

The polymer constituting the insulating fine particles is preferably a polymer of a plurality of types of polymerizable compounds having an ethylenically unsaturated bond, and at least one of the polymerizable compounds having an ethylenically unsaturated bond for forming the polymer. It is preferable that one type has a phosphonium group represented by the formula (1).

Examples of the polymerizable compound having an ethylenically unsaturated bond having a phosphonium group represented by the formula (1) include styrenes, olefins, esters, α and β unsaturated carboxylic acids, amides and nitriles. Be done. Examples of styrenes include nuclear-substituted styrenes such as styrene, o, m, p-methylstyrene, dimethylstyrene, ethylstyrene and chlorostyrene, and styrene derivatives such as α-methylstyrene, α-chlorostyrene and β-chlorostyrene. Can be mentioned. Examples of olefins include ethylene and propylene. Examples of the esters include vinyl esters such as vinyl acetate, vinyl propionate and vinyl benzoate, and methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, phenyl (meth) acrylate and the like. Examples include esters of (meth) acrylic acid. Examples of α and β unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, maleic acid and the like. Salts of these α and β unsaturated carboxylic acids are also included in the α and β unsaturated carboxylic acids. Examples of amides include acrylamide, methacrylamide and the like. Examples of nitriles include acrylonitrile. These may be further substituted, and the substituents include a phosphonium group, an amino group, a quaternary ammonium group, an amide group, a sulfonium group, a sulfonic acid group, a thiol group, a carboxyl group, a phosphoric acid group and a cyano group. Examples thereof include an aldehyde group, an ester group and a carbonyl group. These monomers can be used alone or in combination of two or more.

As the polymerizable compound having an ethylenically unsaturated bond having a phosphonium group represented by the formula (1), styrenes or esters are particularly preferable.
The polymer constituting the insulating fine particles should have a structural unit represented by the following formula (2) or formula (3) as the phosphonium group represented by the above formula (1), that is, the availability of the monomer and the polymer synthesis. It is preferable from the viewpoint of ease of use. Examples of R in the formulas (2) and (3) are as described above as examples of R in the formula (1). The phosphonium group may be bonded to any of the para-position, the ortho-position, and the meta-position with respect to the CH group of the benzene ring of the formula (2), and is preferably bonded to the para-position. In the formula (2) and the formula (3), a halide ion is preferably mentioned as the monovalent An ⁻ . Examples of halide ions include Cl ⁻ , F ⁻ , Br ⁻ , and I ⁻ .

（式中、Ｒはそれぞれ独立に炭素数４～１０のアルキル基を示す。Ａｎ^－は一価のアニオンを示す。ｍは０～５の整数を示す。）

(In the formula, R independently represents an alkyl group having 4 to 10 carbon atoms. An ⁻ represents a monovalent anion. M represents an integer of 0 to 5.)

（式中、Ｒはそれぞれ独立に炭素数４～１０のアルキル基を示す。Ａｎ^－は一価のアニオンを示す。ｎは１～５の数である。Ｒ_５は水素原子又はメチルである。）

(In the formula, R independently represents an alkyl group having 4 to 10 carbon atoms. An ⁻ represents a monovalent anion. n is a number of 1 to 5. R ₅ is a hydrogen atom or methyl. )

In the above formula (2), m is preferably 0 to 2, more preferably 0 or 1, and particularly preferably 1. In the above formula (3), n is preferably 1 to 3, more preferably 1 to 2, and most preferably 2.

As a polymerizable compound having an ethylenically unsaturated bond that gives the compound represented by the above formula (2),
4- (Vinylbenzyl) tributylphosphonium chloride,
4- (Vinylbenzyl) Tripentyl Phosphonium Chloride,
4- (Vinylbenzyl) Trihexyl Phosphonium Chloride,
4- (Vinylbenzyl) triheptylphosphonium chloride,
4- (Vinylbenzyl) trioctylphosphonium chloride,
4- (Vinylbenzyl) Trinonyl Phosphonium Chloride,
4- (Vinylbenzyl) tridecylphosphonium chloride, is mentioned.

As a polymerizable compound having an ethylenically unsaturated bond that gives the compound represented by the above formula (3),
2- (Methylloyloxyethyl) Tributyl Phosphonium Chloride,
2- (Methylloyloxyethyl) Tripentyl Phosphonium Chloride,
2- (Methylloyloxyethyl) Trihexyl Phosphonium Chloride,
2- (Methylloyloxyethyl) triheptylphosphonium chloride,
2- (Methylloyloxyethyl) Trioctyl Phosphonium Chloride,
2- (methacryloyloxyethyl) trinonylphosphonium chloride,
2- (Methylloyloxyethyl) tridecylphosphonium chloride,
And so on.

In the polymer constituting the insulating fine particles, the ratio of the structural unit to which the phosphonium group represented by the formula (1) is bonded is preferably 0.01 mol% or more and 5.0 mol% or less in all the structural units. , 0.02 mol% or more and 2.0 mol% or less is more preferable. Here, as for the number of structural units in the polymer, the structure derived from one monomer is counted as one structural unit.

As described above, the polymer constituting the insulating fine particles is preferably a polymer in which a plurality of types of polymerizable compounds having an ethylenically unsaturated bond are combined. Among the polymerizable compounds having an ethylenically unsaturated bond for constituting the insulating fine particles, the polymerizable compounds having no phosphonium group represented by the formula (1) include the above-mentioned styrenes and olefins. Examples thereof include esters, α and β unsaturated carboxylic acids, amides and nitriles. Examples of styrenes, olefins, esters, α, β unsaturated carboxylic acids, amides, and nitriles include those described above. As the polymer constituting the insulating fine particles, in particular, at least one polymer selected from styrenes, esters and nitriles has a high polymerization rate and can easily make the insulating fine particles spherical. Is preferable. When the polymer constituting the insulating fine particles has a plurality of types of structural units, the mode of existence of these structural units in the polymer may be random, alternate, or block.

The polymer constituting the insulating fine particles may be cross-linked or non-cross-linked, but the cross-linking widens the particle distribution of the insulating fine particles and provides a dense filling property into the conductive particles. It is preferable because it is easy to obtain.
When cross-linking the polymer constituting the insulating fine particles, two or more ethylenically unsaturated bonding groups are added to the composition of the polymerizable compound having an ethylenically unsaturated bond to obtain the polymer constituting the insulating fine particles. A cross-linking agent having the above may be added. Examples of the cross-linking agent include aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; allyl methacrylate, triacrylicformal, triallyl isocyanate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, and triethylene glycol di. (Meta) acrylate, 1,4-butanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, polyethylene glycol di (meth) acrylate, neo Pentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimethylol propantrimethacrylate, glycerin dimethacrylate, dimethylol-tricyclodecanediacrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetraacrylate , Dipentaerythritol hexaacrylate, neopentyl glycol acrylic acid benzoic acid ester, trimethylolpropane acrylic acid benzoic acid ester, 2-hydroxy-3-acryloyloxypropyl methacrylate, hydroxypivalate neopentylglycol diacrylate, ditrimethylol propanetetra Examples thereof include di (meth) acrylate compounds such as acrylate and 2-butyl-2-ethyl-1,3-propanediol diacrylate.

In the polymer constituting the insulating fine particles, the ratio of the structural unit derived from the cross-linking agent to all the structural units is preferably 1 mol% or more and 15 mol% or less, and 2 mol% or more and 13 mol% or less. Is more preferable. Here, as for the number of structural units in the polymer, the structure derived from one monomer is counted as one structural unit.

The polymer constituting the insulating fine particles is a copolymer having two or more kinds of structural units, and it is preferable that at least one kind of the structural units has an ester bond in the structure. As a result, the glass transition temperature of the polymer can be easily lowered to a suitable level, the ratio of the area of the insulating fine particles in contact with the conductive particles can be increased, and the adhesion between the insulating fine particles and the conductive particles can be improved. The degree of bonding between the insulating fine particles can be increased, and the insulating property between the coated particles can be made higher.

Examples of the structural unit having an ester bond in the structure include those derived from a polymerizable compound having both an ethylenically unsaturated bond and an ester bond in the structure. Examples of such polymerizable compounds include the esters listed above, specifically, vinyl esters such as vinyl propionate and vinyl benzoate, methyl (meth) acrylate, ethyl (meth) acrylate, and (meth) acrylic acid. Examples thereof include esters of (meth) acrylic acid such as propyl, butyl (meth) acrylate, hexyl (meth) acrylate, and phenyl (meth) acrylate. In particular, as a polymerizable compound having both an ethylenically unsaturated bond and an ester bond in its structure, a compound having a group represented by -COOR ₁ or -OCOR ₂ (R ₁ and R ₂ are alkyl groups) in its structure. In particular, these groups are H ₂ C = CH * or H ₂ C = C (CH ₃ ) * (* is the bond of the bond in the group represented by -COOR ₁ or -OCOR ₂ above. The compound bonded to the above) is preferable. As R ₁ and R ₂ , a linear or branched alkyl group is preferable, the number of carbon atoms is preferably 1 or more and 12 or less, and more preferably 2 or more and 10 or less. These can be used alone or in combination of two or more.

In the polymer constituting the insulating fine particles, the ratio of the structural units having an ester bond in the structure to the total structural units is from the viewpoint that the glass transition temperature of the insulating fine particles is in a suitable range, and the insulation generated during the progress of the polymerization reaction. From the viewpoint that the sex fine particles can be taken out without being melted by heat and adhering to the wall surface of the reaction vessel, it is preferably 0.1 mol% or more and 30 mol% or less, and more preferably 1 mol% or more and 25 mol% or less. .. A preferable example of the structural unit having an ester bond in the structure referred to here is represented by, for example, the following general formula (4).

（式中、Ｒ_３は水素原子又はメチル基を表す。Ｒ_４は－ＣＯＯＲ_１又は－ＯＣＯＲ_２で表される基である。）

(In the formula, R ₃ represents a hydrogen atom or a methyl group. R ₄ is a group represented by -COOR ₁ or -OCOR _2. )

The glass transition temperature of the insulating fine particles is preferably lower than the glass transition temperature of the core material of the conductive particles. With such a configuration, the ratio of the area of the insulating fine particles in contact with the conductive particles and the adhesion between the insulating fine particles can be easily increased.
In particular, in the present embodiment, by using the insulating fine particles having a phosphonium group on the surface, as described above, the insulating fine particles can be adhered to the conductive particles in a single layer, and the insulating fine particles are glass. By using a material having a low transition temperature, it is possible to more easily improve the adhesion of the insulating fine particles to the conductive particles and the adhesion between the insulating fine particles. Therefore, in the present embodiment, the insulating property between the coated particles can be effectively improved.

More specifically, the glass transition temperature of the insulating fine particles is preferably 100 ° C. or lower, more preferably 95 ° C. or lower, and particularly preferably 90 ° C. or lower.
Further, the glass transition temperature of the insulating fine particles is preferably 40 ° C. or higher, preferably 45 ° C. or higher from the viewpoint of shape stability during storage of the coated particles and the ease of synthesizing the insulating fine particles. It is preferably 50 ° C. or higher, and particularly preferably 50 ° C. or higher. The glass transition temperature can be measured by the method described in Examples described later.

From the same point as above, when the core material has a glass transition temperature, the difference between the glass transition temperature of the insulating fine particles and the glass transition temperature of the core material of the conductive particles is preferably 160 ° C. or less, preferably 120 ° C. The temperature is more preferably 100 ° C. or lower, and particularly preferably 100 ° C. or lower. The difference between the glass transition temperature of the insulating fine particles and the glass transition temperature of the core material of the conductive particles is preferably 5 ° C. or higher, and more preferably 10 ° C. or higher.

Examples of the method for measuring the glass transition temperature include the following methods.
Using a differential scanning calorimeter "STAR SYSTEM" (manufactured by METTLER TOLEDO), 0.04 to 0.06 g of the sample was heated to 200 ° C. and cooled from that temperature to 25 ° C. at a temperature lowering rate of 5 ° C./min. .. Next, the temperature of the sample was raised at a heating rate of 5 ° C./min, and the amount of heat was measured. When a peak is observed, the temperature of the peak is observed, and when a step is observed without a peak, a tangent line indicating the maximum slope of the curve of the step portion and an extension of the baseline on the high temperature side of the step are used. The temperature at the intersection of the above was defined as the glass transition temperature.

The average particle diameter (D) of the insulating fine particles is preferably 10 nm or more and 3,000 nm or less, and more preferably 15 nm or more and 2,000 nm or less. When the average particle diameter of the insulating fine particles is within the above range, it is easy to secure conduction between the counter electrodes without causing a short circuit in the obtained coated particles in a direction different from that between the counter electrodes. In the present invention, the average particle size of the insulating fine particles is a value measured by observation using a scanning electron microscope, and can be specifically measured by the method described in Examples described later.

The particle size distribution of the insulating fine particles measured by the above method varies. Generally, the width of the particle size distribution of the powder is represented by the coefficient of variation (hereinafter, also referred to as “CV”) represented by the following formula (1).
C. V. (%) = (Standard deviation / average particle size) x 100 ... (1)
This C.I. V. A large size indicates a wide range of particle size distributions, while C.I. V. A small value indicates that the particle size distribution is sharp. The coated particles of this embodiment are C.I. V. Is preferably 5% or more, more preferably 7% or more, and most preferably more than 10%. C. V. By setting the above lower limit or more, it becomes easier to cover the surface of the conductive particles with the insulating fine particles. Also, C.I. V. The value is preferably 20% or less, and more preferably 15% or less, from the viewpoint of making the thickness of the coating layer made of the insulating fine particles uniform.

The insulating layer may be a continuous film composed of a polymer and containing a compound having a phosphonium group, instead of the above-mentioned insulating fine particles. "Continuous" of a continuous film refers to coating conductive particles more continuously than insulating fine particles, and does not necessarily cover one conductive particle with only one continuous film. It does not mean that one conductive particle may be intermittently covered with a plurality of films. When the insulating layer is a continuous film containing a compound having a phosphonium group, the metal surface of the conductive particles is exposed by thermocompression bonding the coated particles between the electrodes to melt, deform or peel the continuous film. This enables continuity between the electrodes and provides connectivity. In particular, the metal surface is often exposed by tearing the continuous film by thermocompression bonding the coated particles between the electrodes. On the other hand, in the surface portion of the coated particles facing a direction different from the thermocompression bonding direction, the coating state of the conductive particles by the continuous coating is generally maintained, so that conduction in a direction other than the thermocompression bonding direction is prevented. The insulating film also preferably has a phosphonium group on the surface.

Even when the insulating layer is made of a continuous film, it is easy to prevent oxidation of the metal film by having the phosphonium group represented by the formula (1). When the continuous film is formed by heating the insulating fine particles coated with the conductive particles, or by dissolving the insulating fine particles coated with the conductive particles with an organic solvent, it is a precursor of the insulating layer. Since the insulating fine particles can be densely coated, the continuous film obtained by melting or dissolving the insulating fine particles can densely cover the surface of the conductive particles, and stable insulating properties can be obtained.
When the insulating layer is a continuous film containing a compound having a phosphonium group, the film may cover the entire surface of the conductive particles, or may cover a part of the surface. Further, the surface of the continuous film may be flat, and may have irregularities on a part or all of the surface resulting from melting or dissolving the insulating fine particles. Further, the insulating layer may be in a state in which a continuous film and insulating fine particles are mixed.

The thickness of the continuous film is preferably 10 nm or more from the viewpoint of improving the insulating property in a direction different from that between the counter electrodes, and 3,000 nm or less is preferable for the ease of conduction between the counter electrodes. It is preferable in terms of points. From this point of view, the thickness of the continuous film is preferably 10 nm or more and 3,000 nm or less, and more preferably 15 nm or more and 2,000 nm or less.

Like the insulating fine particles, the phosphonium group represented by the formula (1) in the continuous film preferably forms a part of the chemical structure of the substance as a part of the substance constituting the continuous film. The phosphonium group represented by the formula (1) in the continuous film is preferably contained in at least one structure of the structural unit of the polymer constituting the continuous film. The phosphonium group represented by the formula (1) is preferably chemically bonded to the polymer constituting the continuous film, and more preferably bonded to the side chain of the polymer.
Examples of the phosphonium group represented by the formula (1) of the continuous film include the same phosphonium groups represented by the formula (1) of the insulating fine particles.
Further, as an example of the structural unit of the polymer constituting the continuous film and its composition, examples of the structural unit of the polymer constituting the insulating fine particles and the composition thereof are the same as those mentioned above, and the above-mentioned ones are mentioned. The preferred range of ratios for the building blocks also applies to all continuous films. Examples of the glass transition temperature of the continuous film include those similar to the glass transition temperature of the insulating fine particles described above. As the relationship between the glass transition temperature of the continuous film and the glass transition temperature of the core material particles, the same relationship as the relationship between the glass transition temperature of the insulating fine particles and the glass transition temperature of the core material particles can be mentioned.

Next, a suitable method for producing the coated particles of the present embodiment will be described.
The present production method is a first step of polymerizing a polymerizable composition containing a polymerizable compound having a phosphonium group represented by the formula (1) to obtain insulating fine particles having a phosphonium group on the surface.
It has a second step of mixing the insulating fine particles and the conductive particles to attach the insulating fine particles to the surface of the conductive particles.

(First step)
The above-mentioned polymerizable composition is composed of two or more kinds of polymerizable compounds, and examples thereof include those in which at least one kind has a phosphonium group. Examples of the polymerizable compound include a polymerizable compound having an ethylenically unsaturated bond, which is a constituent unit of the polymer constituting the above-mentioned insulating fine particles. In addition, examples of the preferable polymerizable compound and its constituent ratio include those that give a preferable constituent unit of the polymer constituting the insulating fine particles and a preferable amount ratio thereof.

Examples of the polymerization method include emulsion polymerization, soap-free emulsion polymerization, dispersion polymerization, suspension polymerization and the like. However, in the case of soap-free emulsion polymerization, monodisperse fine particles are used as a surfactant. It is preferable because it has the advantage that it can be manufactured without the need for. In the case of soap-free emulsion polymerization, a water-soluble initiator is used as the polymerization initiator. The polymerization is preferably carried out in an inert atmosphere such as nitrogen or argon.
As a result, insulating fine particles having a phosphonium group represented by the formula (1) on the surface can be obtained.

(Second step)
Next, the insulating fine particles and the conductive particles are mixed to attach the insulating fine particles to the surface of the conductive particles. The mixing of the insulating fine particles and the conductive particles is preferably performed in a liquid medium. Examples of the liquid medium include water, an organic solvent and a mixture thereof, and water is preferable. As the organic solvent, as described later, alcohols such as methanol, ethanol, 1-propanol and 2-propanol can be used as those which do not dissolve the insulating fine particles.
When using a conductive particle having a surface treatment agent on its outer surface, for example, surface treatment such as dispersing the conductive particle in a solution of the surface treatment agent may be performed before mixing with the insulating fine particles. good.

When the insulating fine particles and the conductive particles are mixed in a liquid medium, the dispersion liquid consisting of these particles and the liquid medium may contain an inorganic salt, an organic salt or an organic acid, so that the covering particles have a coverage rate of a certain level or higher. It is preferable because it is easy to obtain. As the inorganic salt, organic salt or organic acid, those that dissociate anions are preferably used, and the anions include ^Cl- , F- ^{, Br- ,} I- ^, SO _4-2 , and CO ₃ ^2- . , NO _3- ^, COO- ^{, RCOO-} (R is an organic group) and the like are suitable. Examples of the inorganic salt include NaCl, KCl, LiCl, MgCl ₂ , BaCl ₂ , NaF, KF, LiF, MgF ₂ , BaF ₂ , NaBr, KBr, LiBr, MgBr ₂ , BaBr ₂ , NaI, KI, LiI, MgI ₂ . , BaI ₂ , Na ₂ SO ₄ , K ₂ SO ₄ , Li ₂ SO ₄ , ו ₄ , Na ₂ CO ₃ , NaHCO ₃ , K ₂ CO ₃ , KHCO ₃ , Li ₂ CO ₃ , LiHCO ₃ , MgCO ₃ , NaNO ₃ , KNO ₃ , LiNO ₃ , MgNO ₃ , BaNO ₃ , and the like can be used. As the organic salt, Na succinate, Na oxalate, Na acetate, Na citrate, Na malonic acid, Na tartrate, Na fumarate, Na maleate and the like can be used. As the organic acid, amino acids such as glycine, succinic acid, oxalic acid, acetic acid, citric acid, tartaric acid, malonic acid, fumaric acid, maleic acid and the like can be used.

The preferred concentrations of the inorganic salt, the organic salt and the organic acid vary depending on how much the insulating fine particles occupy the covering area in the surface area of the conductive particles, but in a dispersion liquid containing the insulating fine particles and the conductive particles, for example. A concentration of 1 mmol / L or more and 100 mmol / L or less is preferable because it has a suitable coverage and it is easy to obtain coated particles in which the insulating fine particles are a single layer. From this viewpoint, the concentrations of the inorganic salt, the organic salt and the organic acid in the dispersion are more preferably 2 mmol / L or more and 90 mmol / L or less, and particularly preferably 3 mmol / L or more and 80 mmol / L or less.

When mixing the insulating fine particles and the conductive particles in the liquid medium, the dispersion liquid containing the insulating fine particles and the conductive particles may be mixed, or the dispersion liquid containing the conductive particles and the insulating fine particles are mixed. Alternatively, the insulating fine particles and the conductive particles may be charged into the liquid medium, respectively, or the dispersion medium containing the insulating fine particles and the dispersion medium containing the conductive particles may be mixed. The dispersion liquid containing the conductive particles and the insulating fine particles preferably contains 100 ppm or more and 100,000 ppm or less of the conductive particles on a mass basis, and more preferably 500 ppm or more and 80,000 ppm or less. ..
The insulating fine particles are preferably contained in a dispersion liquid containing conductive particles and insulating fine particles at a mass content of 10 ppm or more and 50,000 ppm or less, and more preferably 250 ppm or more and 30,000 ppm or less. ..

The temperature of the dispersion liquid containing the conductive particles and the insulating fine particles is generally preferably 15 ° C. or higher and 100 ° C. or lower, from the viewpoint that coated particles having constant quality can be easily obtained, and is 20 ° C. or higher and 90 ° C. or lower. Is particularly preferred. In particular, when the glass transition temperature of the insulating fine particles is Tg ° C., the temperature of the dispersion is preferably Tg-60 ° C. or higher and Tg + 30 ° C. or lower, and more preferably Tg-50 ° C. or higher and Tg + 15 ° C. or lower. .. Within this range, the insulating fine particles adhere to the conductive particles while maintaining their shape, and it is easy to obtain a suitable contact area between the insulating fine particles and the conductive particles, which is preferable. However, since the insulating fine particles having a phosphonium group represented by the formula (1) of the present invention have a high affinity with the conductive particles, they can be sufficiently coated as long as they are within the above temperature range. ..

In the dispersion liquid after mixing the conductive particles, the time for adhering the insulating fine particles to the conductive particles is preferably 0.1 hour or more and 24 hours or less. During this time, it is preferable to stir the dispersion. Then, the solid content of the dispersion liquid is washed and dried as necessary to obtain coated particles in which insulating fine particles having a phosphonium group are attached to the surface of the conductive particles.

As described above, by heating the coated particles in which the insulating fine particles adhere to the surface of the conductive particles, the surface of the conductive particles can be coated in a film shape with the insulating fine particles in a molten state. By forming the insulating fine particles into a film, the insulating property becomes stronger. As a heating method, a method of heating the dispersion liquid after adhering the insulating fine particles to the surface of the conductive particles, a method of heating the coated particles in a solvent such as water, a method of heating the coated particles in an inert gas, etc. Examples include a method of heating in the gas phase. The heating temperature is Tg + 1 ° C or higher and Tg + 60 ° C when the glass transition temperature of the polymer constituting the insulating fine particles is Tg because it is easy to form a uniform film without the insulating fine particles falling off. The following is preferable, Tg + 5 ° C. or higher and Tg + 50 ° C. or lower are more preferable, and Tg + 10 ° C. or higher is most preferable. Further, when the coated particles are heated in the gas phase, the pressure condition can be under atmospheric pressure, reduced pressure or pressurized.

Further, the coated particles in which the insulating fine particles adhere to the surface of the conductive particles can be made into a fluid state by adding an organic solvent to the dispersion liquid, so that the surface of the conductive particles is in the form of a film. Can be covered with. When the insulating fine particles are dissolved, tetrahydrofuran, toluene, methyl ethyl ketone, N-methyl-2-pyrrolidone, N, N-dimethylformamide and the like can be used as the organic solvent. The amount of the organic solvent added should be 1 part by mass or more and 100 parts by mass or less with respect to 1 part by mass of the coated particles in the dispersion liquid because it is easy to form a uniform film without the insulating fine particles falling off. It is preferable, and it is more preferable that it is 5 parts by mass or more and 50 parts by mass or less. The addition temperature is preferably 10 ° C. or higher and 100 ° C. or lower, and more preferably 20 ° C. or higher and 80 ° C. or lower, from the viewpoint that a uniform film shape is easily formed without the insulating fine particles falling off.

The coated particles having the surface of the conductive particles coated in the form of a film may be subjected to an annealing treatment in order to further stabilize the continuous film. Examples of the annealing treatment method include a method of heating the coated particles in a gas phase such as an inert gas. The heating temperature is preferably Tg + 1 ° C. or higher and Tg + 60 ° C. or lower, and more preferably Tg + 5 ° C. or higher and Tg + 50 ° C. or lower, when the glass transition temperature of the polymer constituting the insulating fine particles is Tg. The heating atmosphere is not particularly limited, and the heating can be performed under any conditions of atmospheric pressure, reduced pressure, or pressurization in an inert gas atmosphere such as nitrogen or argon or an oxidizing atmosphere such as air.

Although the preferred production method has been described above, the coated particles of the present invention can also be produced by other production methods. For example, an insulating fine particle having no phosphonium group may be produced in advance by a polymerization reaction, and the obtained insulating fine particle may be reacted with a compound having a phosphonium group to introduce a phosphonium group on the surface of the insulating fine particle. ..

The coated particles obtained as described above utilize the insulating properties between the coated particles and the connectivity between the counter electrodes due to the advantage of combining the conductive particles with the insulating fine particles having a phosphonium group or the continuous coating. , It is suitably used as a conductive material such as a conductive adhesive, an anisotropic conductive film, and an anisotropic conductive adhesive.

Hereinafter, the present invention will be described with reference to examples. However, the scope of the present invention is not limited to these examples. The characteristics in the example were measured by the following method.

(1) Average particle size 200 particles are arbitrarily extracted from a scanning electron microscope (SEM) photograph (magnification: 100,000 times) to be measured, their particle size is measured, and the average value is averaged. The particle size was used. The definition of the average particle size is as described above.

(2) C.I. V. (Coefficient of variation)
From the measurement of the average particle size, it was calculated by the following formula.
C. V. (%) = (Standard deviation / average particle size) x 100

(3) Glass transition temperature With a differential scanning calorimetry device (METTTLER TOLEDO, STAR SYSTEM), the calorific value changes from 25 ° C to 200 ° C at a temperature rise / fall rate of 5 ° C / min and a nitrogen atmosphere using the above procedure. It was measured.

(Example 1)
[Manufacturing of tributylphosphonium-based insulating fine particles]
100 mL of pure water was put into a 200 mL four-necked flask equipped with a stirring blade having a length of 60 mm. After that, styrene monomer (manufactured by Kanto Chemical Industries, Ltd.) 30.00 mmol, n-butyl acrylate (manufactured by Kanto Chemical Industries, Ltd.) 5.3 mmol, 4- (vinylbenzyl) tributylphosphonium chloride (Nippon Kagaku Kogyo Co., Ltd.) 0.30 mmol, divinylbenzene (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) as a cross-linking agent, 1.50 mmol, and 2,2'-azobis (2-methylpropionamidine) dihydrochloride (manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator. , V-50) 0.50 mmol was added. After aerating nitrogen for 15 minutes and expelling dissolved oxygen, the temperature was raised to 60 ° C. and held for 6 hours to proceed with the polymerization reaction. The dispersion liquid of the fine particles after the polymerization was subjected to a SUS sieve having an opening of 150 μm to remove aggregates. The dispersion liquid from which the agglomerates have been removed is centrifuged with a centrifuge (CR-21N, manufactured by Hitachi Koki Co., Ltd.) at 20,000 rpm for 20 minutes to settle the fine particles, and the supernatant liquid is prepared. Removed. Pure water was added to the obtained solid material and washed to obtain spherical fine particles of tributylphosphonium-based insulating fine particles made of a crosslinked resin. The average particle size of the obtained fine particles was 139 nm, and C.I. V. Was 8.6%. The glass transition temperature was about 81 ° C.

[Manufacturing of insulating particles coated with insulating fine particles]
Ni-plated particles (manufactured by Nippon Chemical Industrial Co., Ltd.) having a nickel film with a thickness of 0.125 μm and an average particle diameter of 3 μm were prepared on the surface of the spherical resin particles. The resin particles were made of a crosslinkable acrylic resin and had a glass transition temperature of 120 ° C. 100 mL of pure water was added to 5.0 g of the Ni-plated particles and stirred to obtain a dispersion of Ni-plated particles. The insulating fine particles obtained above and Na ₂ SO ₄ were added to this dispersion, and the mixture was stirred at 40 ° C. for 30 minutes. After the addition of the insulating fine particles and Na ₂ SO ₄ , the solid content concentration of the insulating fine particles in the dispersion was 10,000 ppm on a mass basis, and the concentration of Na ₂ SO ₄ was 5 mmol / L. After removing the supernatant, it was washed with pure water and then vacuum dried at 50 ° C. to obtain insulating fine particle-coated conductive particles. The coverage of the insulating fine particles in the obtained coated particles was determined by the following method. The results are shown in Table 1.

(Example 2)
[Manufacturing of tributylphosphonium-based insulating fine particles]
Insulating fine particles were obtained by the same method as in Example 1.
[Manufacturing of insulating particles coated with insulating fine particles]
Ni-plated particles (manufactured by Nippon Chemical Industrial Co., Ltd.) having a nickel film with a thickness of 0.125 μm and an average particle diameter of 3 μm were prepared on the surface of the spherical resin particles. The resin particles were made of a crosslinkable acrylic resin and had a glass transition temperature of 120 ° C. 100 mL of pure water was added to 5.0 g of the Ni-plated particles and stirred to obtain a dispersion of Ni-plated particles. The insulating fine particles obtained above and NaCl were added to this dispersion, and the mixture was stirred at 40 ° C. for 30 minutes. After the addition of the insulating fine particles and NaCl, the solid content concentration of the insulating fine particles in the dispersion was 10,000 ppm on a mass basis, and the concentration of NaCl was 10 mmol / L. After removing the supernatant, it was washed with pure water and then vacuum dried at 50 ° C. to obtain insulating fine particle-coated conductive particles. The coverage of the insulating fine particles in the obtained coated particles was determined by the following method. The results are shown in Table 1.

(Example 3)
[Manufacturing of tributylphosphonium-based insulating fine particles]
Insulating fine particles were obtained by the same method as in Example 1.
[Manufacturing of insulating particles coated with insulating fine particles]
Ni-plated particles (manufactured by Nippon Chemical Industrial Co., Ltd.) having a nickel film with a thickness of 0.125 μm and an average particle diameter of 3 μm were prepared on the surface of the spherical resin particles. The resin particles were made of a crosslinkable acrylic resin and had a glass transition temperature of 120 ° C. 100 mL of pure water was added to 5.0 g of the Ni-plated particles and stirred to obtain a dispersion of Ni-plated particles. The insulating fine particles obtained above and succinic acid were added to this dispersion, and the mixture was stirred at 40 ° C. for 30 minutes. After the addition of the insulating fine particles and succinic acid, the solid content concentration of the insulating fine particles in the dispersion was 10,000 ppm on a mass basis, and the concentration of succinic acid was 10 mmol / L. After removing the supernatant, it was washed with pure water and then vacuum dried at 50 ° C. to obtain insulating fine particle-coated conductive particles. The coverage of the insulating fine particles in the obtained coated particles was determined by the following method. The results are shown in Table 1.

(Example 4)
[Manufacturing of tributylphosphonium-based insulating fine particles]
Insulating fine particles were obtained by the same method as in Example 1.
[Manufacturing of insulating particles coated with insulating fine particles]
Ni-plated particles (manufactured by Nippon Chemical Industrial Co., Ltd.) having a nickel film with a thickness of 0.125 μm and an average particle diameter of 3 μm were prepared on the surface of the spherical resin particles. The resin particles were made of a crosslinkable acrylic resin and had a glass transition temperature of 120 ° C. 100 mL of pure water was added to 5.0 g of the Ni-plated particles and stirred to obtain a dispersion of Ni-plated particles. 10 mL of a 1% by mass aqueous solution of benzotriazole was added to this dispersion and stirred for 5 minutes for surface treatment. Then, the Ni-plated particles having a layer of benzotriazole on the surface were collected by filtering with a membrane filter having an opening of 2.0 μm. After washing the recovered Ni-plated particles with pure water, 100 mL of pure water was added to obtain a dispersion liquid of Ni-plated particles having a benzotriazole layer on the surface. The insulating fine particles obtained above and Na ₂ SO ₄ were added to this dispersion, and the mixture was stirred at 40 ° C. for 30 minutes. After the addition of the insulating fine particles and Na ₂ SO ₄ , the solid content concentration of the insulating fine particles in the dispersion was 10,000 ppm on a mass basis, and the concentration of Na ₂ SO ₄ was 5 mmol / L. After removing the supernatant, it was washed with pure water and then vacuum dried at 50 ° C. to obtain insulating fine particle-coated conductive particles. The coverage of the insulating fine particles in the obtained coated particles was determined by the following method. The results are shown in Table 1. An SEM photograph of the obtained coated particles is shown in FIG.

(Example 5)
[Manufacturing of tributylphosphonium-based insulating fine particles]
Insulating fine particles were obtained by the same method as in Example 1.
[Manufacturing of insulating particles coated with insulating fine particles]
The surface of the spherical resin particles has 1,030 protrusions having an average height of 0.1 μm, an average base length of 0.197 μm, and an aspect ratio of 0.5, and has a thickness of 0. Ni-plated particles (manufactured by Nippon Kagaku Kogyo Co., Ltd.) having a nickel film of 125 μm and having an average particle diameter of 3 μm were prepared. The resin particles were made of a crosslinkable acrylic resin and had a glass transition temperature of 120 ° C. Further, 100 mL of pure water was added to 5.0 g of the Ni-plated particles and stirred to obtain a dispersion of Ni-plated particles. 10 mL of a 1% by mass aqueous solution of benzotriazole was added to this dispersion and stirred for 5 minutes for surface treatment. Then, the Ni-plated particles having a layer of benzotriazole on the surface were collected by filtering with a membrane filter having an opening of 2.0 μm. After washing the recovered Ni-plated particles with pure water, 100 mL of pure water was added to obtain a dispersion liquid of Ni-plated particles having a benzotriazole layer on the surface. The insulating fine particles obtained above and Na ₂ SO ₄ were added to this dispersion, and the mixture was stirred at 40 ° C. for 30 minutes. After the addition of the insulating fine particles and Na ₂ SO ₄ , the solid content concentration of the insulating fine particles in the dispersion was 10,000 ppm on a mass basis, and the concentration of Na ₂ SO ₄ was 5 mmol / L. After removing the supernatant, it was washed with pure water and then vacuum dried at 50 ° C. to obtain insulating fine particle-coated conductive particles. The coverage of the insulating fine particles in the obtained coated particles was determined by the following method. The results are shown in Table 1.

(Example 6)
[Manufacturing of trioctylphosphonium-based insulating fine particles]
100 mL of pure water was put into a 200 mL four-necked flask equipped with a stirring blade having a length of 60 mm. After that, styrene monomer (manufactured by Kanto Chemical Industries, Ltd.) 30.00 mmol, n-butyl acrylate (manufactured by Kanto Chemical Industries, Ltd.) 5.3 mmol, 4- (vinylbenzyl) trioctylphosphonium chloride (Nippon Kagaku Kogyo Co., Ltd.) ) 0.30 mmol, divinylbenzene (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) as a cross-linking agent, 1.5 mmol, and 2,2'-azobis (2-methylpropionamidine) dihydrochloride (Wako Pure Chemical Industries, Ltd.) as a polymerization initiator , V-50) 0.50 mmol was added. After aerating nitrogen for 15 minutes and expelling dissolved oxygen, the temperature was raised to 60 ° C. and held for 6 hours to proceed with the polymerization reaction. The dispersion liquid of the fine particles after the polymerization was subjected to a SUS sieve having an opening of 150 μm to remove aggregates. The dispersion liquid from which the agglomerates have been removed is centrifuged with a centrifuge (CR-21N, manufactured by Hitachi Koki Co., Ltd.) at 20,000 rpm for 20 minutes to settle the fine particles, and the supernatant liquid is prepared. Removed. Pure water was added to the obtained solid material and washed to obtain spherical fine particles of trioctylphosphonium-based insulating fine particles made of a crosslinked resin. The average particle size of the obtained fine particles was 152 nm, and C.I. V. Was 10.6%. The glass transition temperature was about 82 ° C.
[Manufacturing of insulating particles coated with insulating fine particles]
Insulating fine particle-coated conductive particles were obtained by the same method as in Example 1 except that the insulating fine particles obtained above were used. Specifically, Ni-plated particles (manufactured by Nippon Chemical Industrial Co., Ltd.) having a nickel film having a thickness of 0.125 μm on the surface of spherical resin particles and having an average particle diameter of 3 μm were prepared. The resin particles were made of a crosslinkable acrylic resin and had a glass transition temperature of 120 ° C. 100 mL of pure water was added to 5.0 g of the Ni-plated particles and stirred to obtain a dispersion of Ni-plated particles. The insulating fine particles obtained above and Na ₂ SO ₄ were added to this dispersion, and the mixture was stirred at 40 ° C. for 30 minutes. After the addition of the insulating fine particles and Na ₂ SO ₄ , the solid content concentration of the insulating fine particles in the dispersion was 10,000 ppm on a mass basis, and the concentration of Na ₂ SO ₄ was 5 mmol / L. After removing the supernatant, it was washed with pure water and then vacuum dried at 50 ° C. to obtain insulating fine particle-coated conductive particles. The coverage of the insulating fine particles in the obtained coated particles was determined by the following method. The results are shown in Table 1.

(Example 7)
1.0 g of the insulating fine particle-coated conductive particles obtained in Example 1 was put into 20 mL of pure water, and the mixture was stirred at 95 ° C. for 6 hours. After the stirring was completed, the solid matter was separated by a membrane filter having an opening of 2 μm and then dried to obtain an insulating continuous film-coated conductive particle in which the entire surface of the conductive particle was coated with a film having a thickness of 125 nm. The SEM photograph of the obtained coated particles is shown in FIG.

(Example 8)
1.0 g of the insulating fine particle-coated conductive particles obtained in Example 1 was put into 20 mL of pure water to obtain a dispersion liquid. Tetrahydrofuran (10 mL) was added to this dispersion, and the mixture was stirred at room temperature for 6 hours. After the stirring is completed, the solid matter is separated by a membrane filter having an opening of 2 μm, washed with water, and then dried to obtain continuous film-coated conductive particles in which the entire surface of the conductive particles is coated with a continuous film having a thickness of 100 nm. rice field. The SEM photograph of the obtained coated particles is shown in FIG.

(Comparative Example 1)
[Manufacturing of triethylphosphonium-based insulating fine particles]
100 mL of pure water was put into a 200 mL four-necked flask equipped with a stirring blade having a length of 60 mm. After that, styrene monomer (manufactured by Kanto Chemical Industries, Ltd.) 30.00 mmol, n-butyl acrylate (manufactured by Kanto Chemical Industries, Ltd.) 5.3 mmol, 4- (vinylbenzyl) triethylphosphonium chloride (Nippon Kagaku Kogyo Co., Ltd.) 0.30 mmol, divinylbenzene (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) as a cross-linking agent, 1.5 mmol, and 2,2'-azobis (2-methylpropionamidine) dihydrochloride (manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator , V-50) 0.50 mmol was added. After aerating nitrogen for 15 minutes and expelling dissolved oxygen, the temperature was raised to 60 ° C. and held for 6 hours to proceed with the polymerization reaction. The dispersion liquid of the fine particles after the polymerization was subjected to a SUS sieve having an opening of 150 μm to remove aggregates. The dispersion liquid from which the agglomerates have been removed is centrifuged with a centrifuge (CR-21N, manufactured by Hitachi Koki Co., Ltd.) at 20,000 rpm for 20 minutes to settle the fine particles, and the supernatant liquid is prepared. Removed. Pure water was added to the obtained solid material and washed to obtain spherical fine particles of triethylphosphonium-based insulating fine particles made of a crosslinked resin. The average particle size of the obtained fine particles was 143 nm, and C.I. V. Was 10.7%. The glass transition temperature was about 80 ° C.
[Manufacturing of insulating particles coated with insulating fine particles]
Insulating fine particle-coated conductive particles were obtained by the same method as in Example 1 except that the insulating fine particles obtained above were used. Specifically, Ni-plated particles (manufactured by Nippon Chemical Industrial Co., Ltd.) having a nickel film having a thickness of 0.125 μm on the surface of spherical resin particles and having an average particle diameter of 3 μm were prepared. The resin particles were made of a crosslinkable acrylic resin and had a glass transition temperature of 120 ° C. 100 mL of pure water was added to 5.0 g of the Ni-plated particles and stirred to obtain a dispersion of Ni-plated particles. The insulating fine particles obtained above and Na ₂ SO ₄ were added to this dispersion, and the mixture was stirred at 40 ° C. for 30 minutes. After the addition of the insulating fine particles and Na ₂ SO ₄ , the solid content concentration of the insulating fine particles in the dispersion was 10,000 ppm on a mass basis, and the concentration of Na ₂ SO ₄ was 5 mmol / L. After removing the supernatant, it was washed with pure water and then vacuum dried at 50 ° C. to obtain insulating fine particle-coated conductive particles. The coverage of the insulating fine particles in the obtained coated particles was determined by the following method. The results are shown in Table 1.

(Comparative Example 2)
[Manufacturing of triethylphosphonium-based insulating fine particles]
Insulating fine particles were obtained by the same method as in Comparative Example 1.
[Manufacturing of insulating particles coated with insulating fine particles]
Insulating fine particle-coated conductive particles were obtained by the same method as in Example 2 except that the insulating fine particles obtained above were used. Specifically, Ni-plated particles (manufactured by Nippon Chemical Industrial Co., Ltd.) having a nickel film having a thickness of 0.125 μm on the surface of spherical resin particles and having an average particle diameter of 3 μm were prepared. The resin particles were made of a crosslinkable acrylic resin and had a glass transition temperature of 120 ° C. 100 mL of pure water was added to 5.0 g of the Ni-plated particles and stirred to obtain a dispersion of Ni-plated particles. The insulating fine particles obtained above and NaCl were added to this dispersion, and the mixture was stirred at 40 ° C. for 30 minutes. After the addition of the insulating fine particles and NaCl, the solid content concentration of the insulating fine particles in the dispersion was 10,000 ppm on a mass basis, and the concentration of NaCl was 10 mmol / L. After removing the supernatant, it was washed with pure water and then vacuum dried at 50 ° C. to obtain insulating fine particle-coated conductive particles. The coverage of the insulating fine particles in the obtained coated particles was determined by the following method. The results are shown in Table 1.

(Comparative Example 3)
[Manufacturing of triethylphosphonium-based insulating fine particles]
Insulating fine particles were obtained by the same method as in Comparative Example 1.
[Manufacturing of insulating particles coated with insulating fine particles]
Insulating fine particle-coated conductive particles were obtained by the same method as in Example 3 except that the insulating fine particles obtained above were used. Specifically, Ni-plated particles (manufactured by Nippon Chemical Industrial Co., Ltd.) having a nickel film having a thickness of 0.125 μm on the surface of spherical resin particles and having an average particle diameter of 3 μm were prepared. The resin particles were made of a crosslinkable acrylic resin and had a glass transition temperature of 120 ° C. 100 mL of pure water was added to 5.0 g of the Ni-plated particles and stirred to obtain a dispersion of Ni-plated particles. The insulating fine particles obtained above and succinic acid were added to this dispersion, and the mixture was stirred at 40 ° C. for 30 minutes. After the addition of the insulating fine particles and succinic acid, the solid content concentration of the insulating fine particles in the dispersion was 10,000 ppm on a mass basis, and the concentration of succinic acid was 10 mmol / L. After removing the supernatant, it was washed with pure water and then vacuum dried at 50 ° C. to obtain insulating fine particle-coated conductive particles. The coverage of the insulating fine particles in the obtained coated particles was determined by the following method. The results are shown in Table 1.

(Comparative Example 4)
[Manufacturing of tridodecylphosphonium-based insulating fine particles]
100 mL of pure water was put into a 200 mL four-necked flask equipped with a stirring blade having a length of 60 mm. After that, styrene monomer (manufactured by Kanto Chemical Industries, Ltd.) 30.00 mmol, n-butyl acrylate (manufactured by Kanto Chemical Industries, Ltd.) 5.3 mmol, 4- (vinylbenzyl) tridodecylphosphonium chloride (Nippon Kagaku Kogyo Co., Ltd.) ) 0.30 mmol, divinylbenzene (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) as a cross-linking agent, 1.5 mmol, and 2,2'-azobis (2-methylpropionamidine) dihydrochloride (Wako Pure Chemical Industries, Ltd.) as a polymerization initiator , V-50) 0.50 mmol was added. After aerating nitrogen for 15 minutes and expelling dissolved oxygen, the temperature was raised to 60 ° C. and held for 6 hours to proceed with the polymerization reaction. The dispersion liquid of the fine particles after the polymerization was subjected to a SUS sieve having an opening of 150 μm to remove aggregates. The dispersion liquid from which the agglomerates have been removed is centrifuged with a centrifuge (CR-21N, manufactured by Hitachi Koki Co., Ltd.) at 20,000 rpm for 20 minutes to settle the fine particles, and the supernatant liquid is prepared. Removed. Pure water was added to the obtained solid material and washed to obtain spherical fine particles of tridodecylphosphonium-based insulating fine particles made of a crosslinked resin. The average particle size of the obtained fine particles was 149 nm, and C.I. V. Was 11.7%. The glass transition temperature was about 78 ° C.
[Manufacturing of insulating particles coated with insulating fine particles]
Insulating fine particle-coated conductive particles were obtained by the same method as in Example 1 except that the insulating fine particles obtained above were used. Specifically, Ni-plated particles (manufactured by Nippon Chemical Industrial Co., Ltd.) having a nickel film having a thickness of 0.125 μm on the surface of spherical resin particles and having an average particle diameter of 3 μm were prepared. The resin particles were made of a crosslinkable acrylic resin and had a glass transition temperature of 120 ° C. 100 mL of pure water was added to 5.0 g of the Ni-plated particles and stirred to obtain a dispersion of Ni-plated particles. The insulating fine particles obtained above and Na ₂ SO ₄ were added to this dispersion, and the mixture was stirred at 40 ° C. for 30 minutes. After the addition of the insulating fine particles and Na ₂ SO ₄ , the solid content concentration of the insulating fine particles in the dispersion was 10,000 ppm on a mass basis, and the concentration of Na ₂ SO ₄ was 5 mmol / L. After removing the supernatant, it was washed with pure water and then vacuum dried at 50 ° C. to obtain insulating fine particle-coated conductive particles. The coverage of the insulating fine particles in the obtained coated particles was determined by the following method. The results are shown in Table 1.

(Evaluation of coverage)
The coverage of the coated particles obtained in Examples 1 to 6 and Comparative Examples 1 to 4 was determined by the following method.
The number N of the insulating fine particles when the insulating fine particles were closely packed on the surface of the Ni-plated particles was calculated by the following formula.
N = 4π (R + r) ² / 2√3r ²
(R: radius of Ni-plated particles (nm), r: radius of insulating fine particles (nm))
The number n of the insulating fine particles adhering to the Ni-plated particles was counted by SEM, and the coverage was calculated from the following formula.
Coverage (%) = (n / N) x 100
The coverage used for the evaluation was the average value of 20 Ni-plated particles.

(Evaluation of nickel film)
After holding the coated particles at 85 ° C. and 85% RH for 24 hours, weigh about 1.0 g into a glass petri dish and use an infrared moisture meter FD-610 (manufactured by Ketsuto Chemical Laboratory Co., Ltd.) at 120 ° C. for 30 minutes. The water content was measured under the conditions of. The lower the water content, the easier it is to prevent oxidation of the nickel film.

Claims (7)

It has a conductive metal-coated particles having a metal film formed on the surface of the core material and an insulating layer made of a polymer that coats the metal-coated particles, and the insulating layer is represented by the following formula (1). Coated particles having a group.

(In the formula, R is an alkyl group having 4 or more and 10 or less carbon atoms independently). The coated particle according to claim 1, wherein the insulating layer is composed of a plurality of insulating fine particles or is a continuous film. The coated particles according to claim 2, wherein the insulating layer is composed of a plurality of insulating fine particles or is a continuous film obtained by melting or dissolving the insulating fine particles. The coated particle according to any one of claims 1 to 3, wherein the polymer is crosslinked. C.I. of the insulating fine particles. V. The coated particles according to claim 2 or 3, wherein the amount is 5% or more. The coated particle according to any one of claims 1 to 5, wherein the insulating layer is made of at least one polymer selected from styrenes, esters and nitriles. The coated particle according to any one of claims 1 to 6, wherein the metal film is a nickel or nickel alloy film.

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