WO2012102199A1 - Conductive microparticle, resin particle, and anisotropic conductive material using same - Google Patents

Abstract

Provided is a conductive microparticle that has a low initial resistance value and can maintain a stable connected state while being a minute conductive microparticle. This conductive microparticle has a base material formed from a resin particle and at least one conductive metal layer formed on the surface of the base material. This conductive microparticle is characterized by the number-based average dispersed particle size for the resin particle being 1.0 - 2.5 µm and the modulus of compressive elasticity when the diameter of the resin particle is displaced 10% (10% K value) being 12,000 N/mm² or greater.

Description

Conductive fine particles, resin particles and anisotropic conductive material using the same

The present invention relates to fine conductive fine particles, and particularly relates to conductive fine particles that can reduce the occurrence of short circuits when used for electrical connection.

Conventionally, in assembling electronic devices, a connection method using an anisotropic conductive material has been adopted in order to electrically connect a large number of opposing electrodes and wires. An anisotropic conductive material is a material in which conductive fine particles are mixed with a binder resin, for example, anisotropic conductive paste (ACP), anisotropic conductive film (ACF), anisotropic conductive ink, anisotropic conductive. There are sheets. Here, as the conductive fine particles used for the anisotropic conductive material, those obtained by coating the surfaces of the metal particles and the resin particles as the base material with a conductive metal layer are used.

By the way, in recent years, miniaturization and high functionality of electronic devices have been progressing more and more. Along with this, electronic components mounted on electric devices are being downsized and mounted with high density, and electrodes and wirings in electronic circuits are becoming finer and narrower. As described above, with the progress of miniaturization and narrowing of the electrodes and wirings of electronic circuits, conductive fine particles used for anisotropic conductive materials are also required to have a smaller particle diameter.

As the conductive fine particles having a small particle size, for example, microspheres made of a resin or an inorganic compound, having an average particle size of 0.5 to 2.5 μm and a particle size CV value of 20% or less were used as a base material. Conductive fine particles have been proposed (Patent Document 1). In addition, it has been reported that in conductive particles obtained by subjecting a core made of an organic polymer to metal plating with a predetermined thickness, the hardness of the conductive particles from which good connection resistance is obtained depends on the diameter of the conductive particles. Among them, a conductive particle having a particle diameter of 1 to 2 μm is disclosed (Patent Document 2).

JP 2000-30526 A Japanese Patent No. 4154919

However, when the particle size of the conductive fine particles is simply reduced as in the past, the connection area is smaller than when the particle size is large, so that the initial resistance value is increased and a stable connection state can be maintained. There was a tendency to not.

The present invention has been made in view of the above circumstances, and is a fine conductive fine particle that has a low initial resistance and can maintain a stable connection state, and a base material for the conductive fine particle. An object of the present invention is to provide resin particles used in the above and an anisotropic conductive material using the conductive fine particles.

The present inventors have intensively studied to solve the above problems. As a result, it is important to relatively increase the ratio of the connection area to the particle diameter in order to ensure a stable current amount equivalent to that when the particle diameter is large while reducing the particle diameter of the conductive fine particles. In order to achieve this, it is possible to form an indentation (specifically, slightly deform when connecting) so that the adhesion between the conductive metal layer and the connected body (electrode) is sufficiently maintained in the connected state. It has been found that it is only necessary to improve the characteristic of forming an indentation at the time. When the number-based average dispersed particle diameter is in the range of 1.0 μm to 2.5 μm, the compressive elastic modulus (10% K value) when the particle diameter is displaced by 10% is 12,000 N / mm ^2. It has been found that the conductive fine particles based on the resin particles as described above can form a sufficient indentation on the connected body (electrode), and the present invention has been completed.

That is, the present invention has the following configuration.
(1) Conductive fine particles having a base material composed of resin particles and at least one conductive metal layer formed on the surface of the base material, wherein the number-based average dispersed particle diameter of the resin particles is 1 Conductive fine particles having a compression elastic modulus (10% K value) of 12,000 N / mm ² or more when the diameter of the resin particles is displaced by 10% from 0.0 μm to 2.5 μm.
(2) The number-based average dispersed particle diameter of the resin particles is 2.0 μm or more, and the compression elastic modulus (10% K value) when the diameter of the resin particles is displaced by 10% is 17,000 N / mm ^2. The conductive fine particles according to (1) above.
(3) The number-based average dispersed particle diameter of the resin particles is less than 2.0 μm, and the compression modulus (10% K value) when the diameter of the resin particles is displaced by 10% is 19,600 N / mm ^2. The conductive fine particle according to (1), which is super.
(4) The conductive fine particles according to any one of (1) to (3), wherein the compression fracture deformation rate of the resin particles is 30% or more.
(5) The conductive fine particles according to any one of (1) to (4), wherein a compression elastic modulus (30% K value) when the diameter of the resin particles is displaced by 30% is smaller than the 10% K value.
(6) The conductive fine particles according to any one of (1) to (5), which have an insulating resin layer on at least a part of the surface.
(7) Particles used as a base material for conductive fine particles,
The number-based average dispersed particle diameter is 1.0 μm or more and 2.5 μm or less, and the compression elastic modulus (10% K value) when the particle diameter is displaced by 10% is 12,000 N / mm ² or more. Characteristic resin particles.
(8) The number-based average dispersed particle diameter is 2.0 μm or more, and the compression elastic modulus (10% K value) when the particle diameter is displaced by 10% is 17,000 N / mm ² or more (7 ) Resin particles.
(9) The number-based average dispersed particle diameter is less than 2.0 μm, and the compression elastic modulus (10% K value) when the particle diameter is displaced by 10% is more than 19,600 N / mm ² (7 ) Resin particles.
(10) The resin particle according to any one of (7) to (9), wherein the compressive fracture deformation rate is 30% or more.
(11) The resin particle according to any one of (7) to (10), wherein a compression elastic modulus (30% K value) when the particle diameter is displaced by 30% is smaller than the 10% K value.
(12) An anisotropic conductive material comprising the conductive fine particles according to any one of (1) to (6) dispersed in a binder resin.

According to the conductive fine particles of the present invention, an indentation can be formed at a low pressure with respect to the connected body (electrode), thereby improving the adhesion between the conductive metal layer and the connected body and securing a large connection area. Therefore, it is possible to develop a sufficiently low initial resistance value while maintaining a small diameter, and to maintain a stable connection state.

1. Conductive fine particles The conductive fine particles of the present invention have a base material composed of resin particles and at least one conductive metal layer formed on the surface of the base material.

The present invention aims to improve fine conductive fine particles. Therefore, in the present invention, the resin particles used as the base material for the conductive fine particles have a small particle diameter, and the number-based average dispersed particle diameter is 1.0 μm or more, preferably 1.1 μm or more, more preferably 1.2 μm or more. More preferably, it is 1.3 μm or more, 2.5 μm or less, preferably 2.3 μm or less, more preferably 2.1 μm or less, and further preferably 1.9 μm or less. If the average dispersed particle diameter of the resin particles (base material) is within this range, fine conductive fine particles can be obtained, which can be suitably used for electrical connection of electrodes and wirings that are miniaturized and narrowed.

The number-based variation coefficient (CV value) of the dispersed particle diameter of the resin particles (base material) is preferably 10.0% or less, more preferably 8.0% or less, and still more preferably 5.0. % Or less, more preferably 4.5% or less, particularly preferably 4.0% or less, and most preferably 3.0% or less. As described above, the resin particles having a small variation coefficient of the dispersed particle diameter are not only uniform in the primary particle diameter, but also have a very high monodispersibility of the primary particle diameter. Therefore, by using such resin particles as a base material, conductive fine particles having a uniform particle diameter and suppressed aggregation can be obtained.
The average dispersion particle diameter based on the number of resin particles in the present invention and the coefficient of variation thereof are values measured by a Coulter counter, and the measurement method will be described later in Examples.

Furthermore, if the conductive fine particles are present as coarse particles, the coarse particles may settle when stored as an anisotropic conductive material for a long period of time, which may cause aggregation of the conductive fine particles. Therefore, it is preferable that coarse particles are removed from the resin particles. That is, the resin particle preferably has a particle diameter at an integrated value of 90% of 2.6 μm or less, more preferably 2.2 μm or less, and even more preferably 2.0 μm or less in a number-based integrated distribution curve. . Similar to the average dispersed particle size, the particle size at the integrated value of 90% means the particle size at which the integrated number value is 90% in the number integrated distribution curve measured by a Coulter counter.

In the present invention, it is important that the resin particles used as the base material have a compressive elastic modulus (10% K value) of 12,000 N / mm ² or more when the diameter is displaced by 10%. If the 10% K value of the resin particles is within this range, a sufficient indentation can be formed on the connected body (electrode), thereby improving the adhesion between the conductive metal layer and the connected body and providing a large connection. An area can be secured. 10% K value of the resin particles is preferably 14,000N / mm ² or more, more preferably 15,000N / mm ² or more, more preferably 17,000N / mm ² or more, more preferably 20000 N / mm ² It is above, Preferably it is 50,000 N / mm < ² > or less, More preferably, it is 40,000 N / mm < ² > or less.

In a preferred aspect of the present invention, the number-average resin particle-based average dispersed particle diameter is 2.0 μm or more and 2.5 μm or less, and the compression modulus (10 % K value) is 17,000 N / mm ² or more, or the number-based average dispersed particle diameter of the resin particles is 1.0 μm or more and less than 2.0 μm, and the diameter of the resin particles is 10 The compressive elastic modulus (10% K value) when% displacement is over 19,600 N / mm ² (greater than 19,600 N / mm ² ). With such an aspect, an increase in the resistance value with time in the anisotropic conductive connection state can be suppressed, and excellent connection reliability can be obtained. That is, if the 10% K value of the resin particles is in the above-mentioned range of 12,000 N / mm ² or more, a connection structure having a low connection resistance value regardless of the pressure conditions during anisotropic conductive connection due to good indentation forming ability. However, in order to obtain higher connection reliability, there is a preferable 10% K value range depending on the particle diameter of the resin particles.

The 10% K value of the resin particles can be measured using a known microcompression tester. Preferably, a known microcompression tester (for example, “MCT-W500” manufactured by Shimadzu Corporation) is used. In a compression test in which a load is applied at a load load rate of 2.2295 mN / sec at room temperature at room temperature, the compression load (N) when the particles are deformed until the compression displacement becomes 10% of the particle diameter It is preferable to measure the compression displacement (mm) and adopt a value obtained based on the following formula.

(Here, E: compression elastic modulus (N / mm ² ), F: compression load (N), S: compression displacement (mm), R: radius of particle (mm))

In the present invention, the resin particles used as a base material preferably have a compressive fracture deformation rate of 30% or more. Since such resin particles have a restoring force in a state of being largely compressed and deformed, the connection area can be further increased. The compression fracture deformation rate of the resin particles is more preferably 40% or more, and further preferably 50% or more. As for the upper limit of the compression fracture deformation rate, it is preferable that there is no fracture point, but it can also be used at 80% or less (particularly 70% or less). The compression fracture deformation rate is a load applied at a load load rate of 2.2295 mN / sec in the center direction of the particles at room temperature using a known micro-compression tester (for example, “MCT-W500” manufactured by Shimadzu Corporation). In the compression test, the compression displacement (μm) when the particles are broken is measured, and is a value calculated by the following formula. For example, when “MCT-W500” manufactured by Shimadzu Corporation is used as a micro-compression tester, measurement is preferably performed in the “standard surface detection” mode provided in the tester.
Compression fracture change rate (%) = [compression displacement (μm) / particle diameter (μm)] × 100

In the present invention, the resin particles used as a base material preferably have a compressive elastic modulus (30% K value) smaller than the 10% K value when the diameter of the resin particles is displaced by 30%. If the 30% K value is 10% K value or higher, a high pressure is required to secure the area due to deformation, but the particles break at this high pressure, and the restoring force of the particles is lost, resulting in connection stability. May decrease. Conversely, if the 30% K value of the resin particles is smaller than the 10% K value, large compression deformation can be secured at low pressure. Specifically, the 30% K value / 10% K value is preferably 0.9 or less, more preferably 0.8 or less, and even more preferably 0.7 or less. Further, in addition to biting into the electrode at the initial stage of compression, the 30% K value / 10% K value is preferably 0.3 or more, and more preferably 0.4 or more, in that the electrode biting property can be further improved.

For the same reason, the compression modulus (20% K value) when the diameter of the resin particles is displaced by 20% is preferably smaller than the 10% K value, and the value of 20% K value / 10% K value is Preferably it is 0.8 or less, More preferably, it is 0.7 or less, Preferably it is 0.4 or more, More preferably, it is 0.5 or more. Further, for the same reason, the compressive elastic modulus (40% K value) when the diameter of the resin particles is displaced by 40% is preferably 2.0 or less, more preferably 1.0 or less, and preferably 0.4 or more, 0.5 or more is more preferable. In order to obtain a connection state with high connection reliability, it is desirable to press-connect in a state where the compression deformation rate is compressed to about 30% to 50% at the time of heating connection. Therefore, not only the 10% K value but also 20% K The value, 30% K value, and 40% K value are also preferably in the above-described ranges.

The 20% K value, 30% K value, and 40% K value of the resin particles are 20%, 30%, or 40% of the particle diameter in the compression test similar to the 10% K value. The compressive load (N) and the compressive displacement (mm) when the particles are deformed up to can be measured and obtained based on the same formula as the 10% K value.

The resin particles (base material) need only contain a resin component, and are not limited to particles composed only of organic materials, but may be particles composed of organic-inorganic composite materials. By using resin particles as a base material, conductive fine particles having excellent elastic deformation characteristics can be obtained.
Examples of the organic material constituting the resin particles include polyolefins such as polyethylene, polypropylene, polyvinyl chloride, polytetrafluoroethylene, polyisobutylene and polybutadiene; vinyl heavy resins such as styrene resins, acrylic resins and styrene-acrylic resins. Polyesters such as polyethylene terephthalate and polyethylene naphthalate; polycarbonates; polyamides; polyimides; phenol formaldehyde resins; melamine formaldehyde resins; melamine benzoguanamine formaldehyde resins; urea formaldehyde resins; Examples of the organic / inorganic composite material include a material containing the organic material and a polysiloxane skeleton (for example, a material in which a polysiloxane skeleton and a vinyl polymer are combined). Thus, the material constituting the resin particles is appropriately selected from a wide range of materials so that the average particle diameter and the 10% K value can be controlled within the above-described ranges. The material which comprises these resin particles may be used independently, and 2 or more types may be used together.

As the material constituting the resin particles, a material containing at least one of a vinyl polymer and a polysiloxane skeleton is preferable. Resin particles composed of a material containing a vinyl polymer have an organic skeleton formed by polymerizing vinyl groups, and are excellent in elastic deformation during pressure connection. Moreover, the resin particle comprised with the material containing polysiloxane frame | skeleton is excellent in the contact pressure with respect to a to-be-connected body at the time of pressure connection. In particular, resin particles composed of a material in which a polysiloxane skeleton and a vinyl polymer are combined are preferable because they are excellent in elastic deformability and contact pressure, and the connection reliability of the obtained conductive fine particles becomes more excellent.

The vinyl polymer is obtained by polymerizing a vinyl group-containing monomer (radical polymerization). In the present invention, the “vinyl group” includes not only a carbon-carbon double bond but also a (meth) acryloxy group, an allyl group. In addition, a substituent having a polymerizable carbon-carbon double bond such as an isopropenyl group, a vinylphenyl group, and an isopropenylphenyl group is also included. In the present specification, “(meth) acryloyl group”, “(meth) acryloxy group”, “(meth) acrylate” or “(meth) acryl” are respectively “one or both of acryloyl group and methacryloyl group”, “One or both of acryloxy group and methacryloxy group”, “one or both of acrylate and methacrylate” and “one or both of acrylic and methacryl” shall be indicated.

The vinyl group-containing monomer includes a monomer having one vinyl group in one molecule (1), one vinyl group in one molecule and a functional group other than vinyl groups (such as a carboxyl group and a hydroxy group). A monomer (2) having a protonic hydrogen-containing group, a terminal functional group such as an alkoxy group) and the like (2), and a monomer (3) having two or more vinyl groups in one molecule. Here, the monomer (1) is a vinyl non-crosslinkable monomer. Monomer (2) can form a cross-linked structure when a reactive (bonding) group such as a carboxyl group, a hydroxy group, or an alkoxy group is present in another monomer. When it becomes a monomer but the group to be a reaction partner does not exist in other monomers, it becomes a vinyl-based non-crosslinkable monomer. The monomer (3) is a vinyl-based crosslinkable monomer. These monomers (1) to (3) may be used alone or in combination of two or more.

Examples of the monomer (1) (vinyl-based non-crosslinkable monomer) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, and isobutyl ( (Meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) Alkyl (meth) acrylates such as acrylate and 2-ethylhexyl (meth) acrylate; cyclopropyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cyclooctyl (meth) acrylate Cycloalkyl (meth) acrylates such as cycloundecyl (meth) acrylate, cyclododecyl (meth) acrylate, isobornyl (meth) acrylate, 4-t-butylcyclohexyl (meth) acrylate; phenyl (meth) acrylate, benzyl (meth ) Aromatic ring-containing (meth) acrylates such as acrylate, tolyl (meth) acrylate, phenethyl (meth) acrylate; styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, pt -Styrene monofunctional monomers such as alkylstyrenes such as butylstyrene, halogen group-containing styrenes such as o-chlorostyrene, m-chlorostyrene, and p-chlorostyrene;

Examples of the monomer (2) (vinyl-based crosslinkable monomer or vinyl-based non-crosslinkable monomer) include monomers having a carboxyl group such as (meth) acrylic acid; 2-hydroxyethyl ( A single group having a hydroxy group such as a hydroxy group-containing (meth) acrylate such as (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, or a hydroxy group-containing styrene such as p-hydroxystyrene. Isomers; alkoxy group-containing (meth) acrylates such as 2-methoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, alkoxystyrenes such as p-methoxystyrene, etc. A monomer having an alkoxy group of

Examples of the monomer (3) (vinyl-based crosslinkable monomer) include allyl (meth) acrylates such as allyl (meth) acrylate; ethylene glycol di (meth) acrylate, 1,4-butanediol di (Meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, 1,3-butylene di (meth) acrylate Alkanediol di (meth) acrylate such as: diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, decaethylene glycol di (meth) acrylate, pentadecaethylene glycol di (meth) acrylate, pentacontactor ethylene glycol Di (meta) Di (meth) acrylates such as polyalkylene glycol di (meth) acrylates such as acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate; trimethylolpropane tri Tri (meth) acrylates such as (meth) acrylate; Tetra (meth) acrylates such as pentaerythritol tetra (meth) acrylate; Hexa (meth) acrylates such as dipentaerythritol hexa (meth) acrylate; Divinylbenzene, divinyl Aromatic hydrocarbon crosslinking agents such as naphthalene and derivatives thereof (preferably styrenic polyfunctional monomers such as divinylbenzene); N, N-divinylaniline, divinyl ether, di Alkenyl sulfide, hetero atom-containing crosslinking agents such as divinyl sulfonic acid; and the like.

The polysiloxane skeleton is obtained by hydrolytic condensation of a silane monomer, and the silane monomer is roughly classified into a silane non-crosslinkable monomer and a silane crosslinkable monomer. The
Examples of the silane-based non-crosslinkable monomer include bifunctional silane-based monomers such as dimethyldimethoxysilane and dialkylsilane such as dimethyldiethoxysilane; and trialkylsilanes such as trimethylmethoxysilane and trimethylethoxysilane. And monofunctional silane-based monomers. These silane non-crosslinkable monomers may be used alone or in combination of two or more.

The silane-based crosslinkable monomer is not particularly limited as long as it can form a crosslinked structure. Examples of the crosslinked structure formed by the silane-based crosslinking monomer include those that crosslink an organic polymer skeleton (for example, a vinyl polymer skeleton) and an organic polymer skeleton (first form); a polysiloxane skeleton; One that crosslinks a polysiloxane skeleton (second form); one that crosslinks an organic polymer skeleton and a polysiloxane skeleton (third form).

Examples of those that can form the first form include dimethyldivinylsilane, methyltrivinylsilane, and tetravinylsilane. Examples of what can form the second form include tetrafunctional silane monomers such as tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, and tetrabutoxysilane; methyltrimethoxysilane, methyltriethoxysilane And trifunctional silane monomers such as ethyltrimethoxysilane and ethyltriethoxysilane. Those that can form the third form include, for example, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, Those having a (meth) acryloyl group such as 3-methacryloxypropylmethyldiethoxysilane, 3-acryloxypropyltriethoxysilane, 3-methacryloxyethoxypropyltrimethoxysilane; vinyltrimethoxysilane, vinyltriethoxysilane, p -Having a vinyl group such as styryltrimethoxysilane; 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxy Those having an epoxy group such as a silane; 3-aminopropyltrimethoxysilane, those having an amino group such as 3-aminopropyltriethoxysilane; and the like. These silane crosslinking monomers may be used alone or in combination of two or more.

As described above, the resin particles are preferably made of a material containing at least one of a vinyl polymer and a polysiloxane skeleton. In other words, a vinyl crosslinkable monomer or vinyl noncrosslinkable monomer that forms a vinyl polymer, or a silane crosslinkable monomer or silane noncrosslinkable monomer that forms a polysiloxane skeleton. It is preferable that the monomer component to be contained is polymerized. In particular, in order to control the 10% K value of the resin particles to 12,000 N / mm ² or more, the resin particles are composed of a material containing at least one of a crosslinked vinyl polymer and a crosslinked polysiloxane skeleton. It is preferable that the resin particles satisfy the following conditions.

That is, in order to set the 10% K value of the resin particles to 12,000 N / mm ² or more, for example, as a monomer component for forming resin particles, a vinyl-based crosslinkable monomer and a silane are first used. Using at least one of the system crosslinkable monomers (hereinafter sometimes simply referred to as “crosslinkable monomer”), the total content thereof is 20% by mass or more based on the total amount of monomer components ( (Preferably 30% by mass or more, more preferably 50% by mass or more) (Condition A). And while satisfying the condition A, the total of the silane crosslinkable monomer and the silane noncrosslinkable monomer is less than 95% by mass in all monomer components (condition B), or silane The total of the system crosslinkable monomer and the silane noncrosslinkable monomer is 95% by mass or more in the total monomer components so that the obtained particles are not heated at a temperature of 200 ° C. or higher ( Condition C). That is, when the condition A and the condition B are satisfied or the condition A and the condition C are satisfied, resin particles having a 10% K value of 12,000 N / mm ² or more can be obtained. Specifically, when the above condition A is satisfied, the resin particles are crosslinked with at least one of a vinyl crosslinkable monomer and a silane crosslinkable monomer. Under the condition B, the resin particles are crosslinked mainly with a vinyl-based crosslinking monomer, and under the condition C, crosslinking with a silane-based crosslinking monomer is mainly performed.
By the way, the silane crosslinking monomer forms a siloxane bond by a condensation reaction to form a crosslinked structure, but the condensation reaction may not sufficiently proceed at the stage after polymerization. Therefore, when a large amount of silane crosslinkable monomer is used, it is recommended that the resin particles after polymerization be baked (heat treatment at a high temperature). However, depending on the degree of thermal history of the resin particles after polymerization, the 10% K value may be greatly reduced. Therefore, in the case of the above condition C, it is necessary to limit heating to the resin particles after polymerization.

The heating specified in the condition C is intended for all heat treatments performed on the particles after synthesizing the resin particles, and the above-described firing (condensation reaction derived from the silane monomer (siloxane bond) In addition to heating performed for the purpose of promoting formation), for example, heating during drying after synthesis of resin particles is targeted.
In the heating specified by the above condition C, it is preferable to set the heating temperature to a predetermined range and the heating atmosphere to an inert gas atmosphere such as nitrogen.
On the other hand, for the resin particles that satisfy the above conditions A and B, the heating conditions for the polymer particles after polymerization are not limited, but when heated, the heating should be performed within the temperature range below the thermal decomposition temperature. Is preferred. Also in this case, it is preferable that the atmosphere during the heat treatment is an inert gas atmosphere such as nitrogen.

The monomer component satisfying the condition A and the condition B or the condition A and the condition C includes at least one of a vinyl-based crosslinkable monomer and a silane-based crosslinkable monomer. The vinyl crosslinkable monomer and the silane crosslinkable monomer that are more suitable for controlling the 10% K value to 12,000 N / mm ² or more with certainty will be described below.

As the vinyl-based crosslinkable monomer, the above-mentioned monomer (3) is preferable in order to more reliably control the 10% K value. Among them, a monomer having two or more (meth) acryloyl groups in one molecule (that is, a monomer having two or more acryloyl groups in one molecule or two or more methacryloyl groups in one molecule). Monomer) and one or both of styrenic polyfunctional monomers are more preferred.

The monomer having two or more (meth) acryloyl groups in one molecule has two (meth) acryloyl groups in one molecule in that resin particles having a high 10% K value are easily obtained. Preferred monomers (di (meth) acrylates) are preferred. Among the di (meth) acrylates, for the same reason, alkanediol di (meth) acrylate and polyalkylene glycol di (meth) acrylate are more preferable, and in particular, there is little decrease in particle strength after coating the conductive metal layer. Therefore, alkanediol di (meth) acrylate is preferable. Further, among di (meth) acrylates, molecules having 6 to 14 atoms present between carbon-carbon double bonds (C═C) in two (meth) acryloyl groups. A di (meth) acrylate having a structure is particularly preferred. Here, the number of atoms existing continuously between the carbon-carbon double bonds shall not count the carbon atoms of the carbon-carbon double bond (C = C) itself, and between (meth) acryloyl groups When there are a plurality of atomic chains connecting the two, the number of atoms in the shortest atomic chain is taken.

As the styrenic polyfunctional monomer, resin particles having a high 10% K value are easily obtained, and a single monomer having two vinyl groups in one molecule in that there is little decrease in particle strength after coating with a conductive metal layer. (Bifunctional vinyl group-containing monomer) is preferable, and divinylbenzene is particularly preferable.

The content of the vinyl-based crosslinkable monomer in the monomer component for forming the resin particles is preferably 10% by mass or more, more preferably 30% by mass or more, and further preferably 50% by mass or more. When the content of the vinyl crosslinking monomer is within this range, the 10% K value can be more reliably controlled to 12,000 N / mm ² or more.

As the silane-based crosslinkable monomer, in order to more reliably control the 10% K value, the above-described silane-based crosslinkable monomer that can form the crosslinked structure of the third form is a particle having high hardness. Is preferable because it is easy to obtain. When the silane crosslinkable monomer is used, the resin particle contains a polysiloxane skeleton formed by hydrolysis and condensation of a silane monomer containing the silane crosslinkable monomer. Preferably, the polysiloxane skeleton formed by hydrolyzing and condensing at least the silane-based crosslinkable monomer capable of forming the crosslinked structure of the third form is a carbon-carbon capable of radical polymerization. It has a skeleton derived from a polymerizable polysiloxane having a double bond (for example, vinyl group, (meth) acryloyl group).

As the silane-based crosslinkable monomer capable of forming the crosslinked structure of the third form, those having a (meth) acryloyl group, those having a vinyl group, or those having an epoxy group are preferred, and more preferably ( Those having a (meth) acryloyl group and those having a vinyl group, more preferably those having a (meth) acryloyl group. Among those having a (meth) acryloyl group, 3-methacryloxypropyltrimethoxysilane and 3-methacryloxypropylmethyldimethoxysilane are particularly preferable, and among those having a vinyl group, vinyltrimethoxysilane is particularly preferable.

The monomer component satisfying the condition A and the condition B or the condition A and the condition C includes at least one of a vinyl crosslinkable monomer and a silane crosslinkable monomer. It can also contain at least one of a crosslinkable monomer and a silane non-crosslinkable monomer. In particular, the inclusion of a vinyl-based non-crosslinkable monomer is preferable because compression deformation characteristics such as recovery characteristics (restorability) and fracture strength can be easily controlled.

As the vinyl non-crosslinkable monomer, the above-described monomer (1) is preferable, and more preferably, alkyl (meth) acrylates, cycloalkyl (meth) acrylates, aromatic ring-containing (meth) acrylates. , A styrene-based monofunctional monomer. Among them, alkyl (meth) acrylates having an alkyl group having 4 or less carbon atoms, 6 carbon atoms in that a resin particle having a high 10% K value can be easily obtained while controlling recovery characteristics (restorability) and fracture strength. Cycloalkyl (meth) acrylates having the following cycloalkyl and styrenic monofunctional monomers are preferred, and styrenic monofunctional monomers are particularly preferred for obtaining resin particles having a high 10% K value.
As the styrene monofunctional monomer, styrene is more preferable because resin particles having a high 10% K value can be easily obtained. Among alkyl (meth) acrylates having an alkyl group having 4 or less carbon atoms, n-butyl acrylate, n-butyl methacrylate, and methyl methacrylate are preferable. Among the cycloalkyl (meth) acrylates having a cycloalkyl having 6 or less carbon atoms, cyclohexyl acrylate and cyclohexyl methacrylate are preferable.
For example, when the monomer (1) contains a styrenic monofunctional monomer, the monomer (3) has a monomer having two or more (meth) acryloyl groups in one molecule or a styrene-based polyfunctional monomer. An embodiment containing a functional monomer is preferred.

A monomer component suitable for controlling the 10% K value of the resin particles as described above to 12,000 N / mm ² or more is (i) having a vinyl crosslinkable monomer and a silane crosslinkable monomer. A form having no monomer, (ii) a form having a silane crosslinking monomer and no vinyl crosslinking monomer, (iii) a vinyl crosslinking monomer and a silane crosslinking monomer It is roughly classified into a form having a mer. Particularly preferred combinations of monomers in the respective forms are as follows.
In the case of the form of (i) (form having a vinyl-based crosslinkable monomer and not having a silane-based crosslinkable monomer); carbon-carbon double bonds (C = C) in two (meth) acryloyl groups C) The number of atoms existing in succession (however, carbon atoms of carbon-carbon double bonds (C = C) are not counted, and there are multiple atomic chains connecting (meth) acryloyl groups) Is a combination of di (meth) acrylate having 6 to 14 atoms and the monofunctional styrene monomer.
In the case of the form (ii) (form having a silane crosslinkable monomer and no vinyl crosslinkable monomer); a silane crosslinkable monomer having a (meth) acryloyl group or vinyl group in the molecule A combination of monomers (for example, a combination of 3-methacryloxypropyltrimethoxysilane and 3-methacryloxypropylmethyldimethoxysilane).
In the case of the form (iii) (form having a vinyl crosslinkable monomer and a silane crosslinkable monomer); a silane crosslinkable monomer having a (meth) acryloyl group, and a styrene polyfunctional monomer A combination with di (meth) acrylate having 6 to 14 atoms present between carbon-carbon double bonds (C═C) in two (meth) acryloyl groups, or A combination of a silane crosslinkable monomer having a (meth) acryloyl group, a styrene polyfunctional monomer, and a styrene monofunctional monomer.

When the average dispersed particle diameter based on the number of the resin particles is 2.0 μm or more and 2.5 μm or less, the 10% K value of the resin particles is 10% as described above in order to make the 10% K value of the resin particles 17,000 N / mm ² or more In addition to the conditions for satisfying the K value of 12,000 N / mm ² or more (satisfying both condition A and condition B, or satisfying both condition A and condition C), the following condition x and the following condition a is satisfied, or the following condition x and the following condition b1 are satisfied. However, when the combination of the condition A and the condition C is selected as a condition for making the 10% K value 12,000 N / mm ² or more, the condition x and the condition a are satisfied.
Condition x: The content of the silane crosslinkable monomer in the monomer component for forming the resin particles is 50% by mass or more based on the total amount of the monomer components, or the silane crosslinkable single amount If the content of the body is less than 50% by mass with respect to the total amount of monomer components, the content of the vinyl-based crosslinkable monomer in the monomer component is 35% by mass or more with respect to the total amount of monomer components. is there.
Condition a: The content of ethyl vinyl benzene in the monomer component for forming the resin particles is 1% by mass or less based on the total amount of the monomer component.
Condition b1: A monomer for forming resin particles when the content of ethyl vinyl benzene in the monomer component for forming resin particles exceeds 1% by mass with respect to the total amount of monomer components The content of the vinyl crosslinkable monomer in the component is 80% by mass or more based on the total amount of the monomer components, and the resin particles are heated at 200 ° C. or higher.

When the particle diameter of the resin particles is relatively large (that is, when the number-based average dispersed particle diameter is 2.0 μm or more), a higher degree of crosslinking is required to further increase the 10% K value. When the above condition x is satisfied, the crosslinking degree can be further improved by 50% by mass or more of the silane-based crosslinking monomer or 35% by mass or more of the vinyl-based crosslinking monomer. In addition, the content of ethyl vinyl benzene that does not contribute to crosslinking in the monomer component is controlled to 1% by mass or less (the above condition a), or the content of ethyl vinyl benzene exceeds 1% by mass. If present, in order to compensate for this, the content of the vinyl-based crosslinkable monomer is set to 80% by mass or more, and the crosslinking is promoted by predetermined heating (the above condition b1). This ensures higher cross-linking.

On the other hand, when the average dispersion particle size based on the number of the resin particles is 1.0 μm or more and less than 2.0 μm, the 10% K value of the resin particles is larger than 19,600 N / mm ² as described above. In addition to the condition for satisfying 10% K value of 12,000 N / mm ² or more (satisfying both condition A and condition B, or satisfying both condition A and condition C), the above condition a Or the following condition b2 is satisfied. However, when the condition A and the condition C are selected as conditions for setting the 10% K value to 12,000 N / mm ² or more, the condition a is satisfied.
Condition b2: a monomer for forming resin particles when the content of ethyl vinyl benzene in the monomer component for forming resin particles exceeds 1% by mass with respect to the total amount of monomer components The content of the vinyl crosslinkable monomer in the component is 35% by mass or more based on the total amount of the monomer components, and the resin particles are heated at 200 ° C. or higher.

When the particle size of the resin particles is small (that is, when the number-based average dispersed particle size is less than 2.0 μm), the 10% K value is increased even at a relatively low degree of crosslinking as compared with the case where the particle size is large. be able to. That is, the degree of cross-linking required to further increase the 10% K value tends to decrease as the particle size decreases. Therefore, when the number-based average dispersed particle size of the resin particles is less than 2.0 μm, the above-mentioned condition x is not necessary, and even when the content of ethylvinylbenzene exceeds 1% by mass, By setting the content of the system crosslinkable monomer to 35% by mass or more (the above condition b2), higher crosslinking is ensured.

In order to set the compression fracture deformation rate and 20% to 40% K value of the resin particles within the above-described range, for example, a vinyl-based crosslinkable monomer is included as a monomer component for forming the resin particles. A monomer having two vinyl groups in one molecule (bifunctional vinyl) of 50% by mass or more (more preferably 60% by mass or more, more preferably 70% by mass or more) of the vinyl-based crosslinkable monomer. Group-containing monomer). Furthermore, the bifunctional vinyl group-containing monomer is 40% by mass or more (more preferably 50% by mass or more) in the crosslinkable monomer (total amount of vinyl crosslinkable monomer and silane crosslinkable monomer). It is also effective to set the compression fracture deformation rate and 20% to 40% K value in the above-described ranges.

The method for producing the resin particles is not particularly limited, and examples thereof include emulsion polymerization, suspension polymerization, dispersion polymerization, seed polymerization, sol-gel seed polymerization, and the like. The particle diameter of the resin particles is within the predetermined range described above. For example, a method of classifying resin particles after synthesizing them by a seed polymerization method is preferably employed. By employing a seed polymerization method for the synthesis of resin particles, resin particles having a small particle size distribution can be obtained. Furthermore, the average particle diameter can be adjusted to a desired range by classifying the synthesized resin particles and removing coarse particles.

The seed polymerization method includes a seed particle preparation step, an absorption step, and a polymerization step. For example, when synthesizing particles composed only of an organic material, seed particles may be prepared from the vinyl monomer, and particles composed of an organic material and a material having a polysiloxane skeleton are synthesized. In this case, seed particles (polysiloxane particles) may be prepared from the silane monomer.

As a method of preparing seed particles from a vinyl monomer, a conventionally used method can be employed, and examples thereof include soap-free emulsion polymerization and dispersion polymerization. In this case, it is preferable to use a styrene monofunctional monomer such as styrene as a monomer component for forming seed particles.

As a method for preparing seed particles (polysiloxane particles) from a silane-based monomer, there may be mentioned a method of hydrolyzing in a solvent containing water and performing condensation polymerization. As the silane monomer, the above-mentioned silane crosslinkable monomer and silane noncrosslinkable monomer can be used. When a polysiloxane skeleton and a vinyl polymer are combined, a silane-based crosslinkable monomer having a radical polymerizable group is used as the silane monomer, and polymerizable polysiloxane particles (radically polymerizable) are used. Particles having a polysiloxane skeleton having a group) may be prepared. Hydrolysis and polycondensation can employ any method such as batch, split, and continuous. In the hydrolysis and condensation polymerization, basic catalysts such as ammonia, urea, ethanolamine, tetramethylammonium hydroxide, alkali metal hydroxide, and alkaline earth metal hydroxide can be preferably used as the catalyst.

In the solvent containing water, an organic solvent can be contained in addition to water and the catalyst. Examples of the organic solvent include alcohols such as methanol, ethanol, isopropanol, n-butanol, isobutanol, sec-butanol, t-butanol, pentanol, ethylene glycol, propylene glycol, 1,4-butanediol; acetone, Examples thereof include ketones such as methyl ethyl ketone; esters such as ethyl acetate; (cyclo) paraffins such as isooctane and cyclohexane; aromatic hydrocarbons such as benzene and toluene. These may be used alone or in combination of two or more.

In the hydrolytic condensation, anionic, cationic and nonionic surfactants and polymer dispersants such as polyvinyl alcohol and polyvinylpyrrolidone can be used in combination. These may be used alone or in combination of two or more. Hydrolytic condensation is performed by mixing a silane monomer as a raw material and a solvent containing a catalyst, water, and an organic solvent, and then at a temperature of 0 ° C. to 100 ° C., preferably 0 ° C. to 70 ° C., for 30 minutes or more. It can carry out by stirring for 100 hours or less.

In the absorption step, the monomer component is absorbed by the seed particles. The method of absorption is not particularly limited as long as it proceeds in the presence of the monomer component in the presence of seed particles. Therefore, the monomer component may be added to the solvent in which the seed particles are dispersed, or the seed particles may be added to the solvent containing the monomer component. Especially, it is preferable to add a monomer component in the solvent which disperse | distributed seed particle | grains previously like the former. In particular, the method of adding the monomer component to the reaction solution without taking out the seed particles obtained in the hydrolysis and condensation step from the reaction solution (seed particle dispersion) does not complicate the process and increases productivity. It is preferable because it is excellent.

In the absorption step, the timing of addition of the monomer component is not particularly limited, and may be added all at once, may be added in several times, or may be fed at an arbitrary rate. In addition, when adding the monomer component, either the monomer component alone or the monomer component solution may be added, but the monomer component is previously added to water or an aqueous medium with an emulsifier. It is preferable to mix the emulsified and emulsified liquid with the seed particles because absorption into the seed particles is performed more efficiently.

The emulsifier is not particularly limited. For example, an anionic surfactant, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxysorbitan fatty acid ester, polyoxyethylene alkyl Nonionic surfactants such as amines, glycerin fatty acid esters, and oxyethylene-oxypropylene block polymers are preferable because they can stabilize the dispersed state of the seed particles after absorbing the seed particles and monomer components. These emulsifiers may be used alone or in combination of two or more.

Further, when emulsifying and dispersing the monomer component with an emulsifier, it is preferable to use water or a water-soluble organic solvent that is 0.3 to 10 times the mass of the monomer component. Examples of the water-soluble organic solvent include alcohols such as methanol, ethanol, isopropanol, n-butanol, isobutanol, sec-butanol, t-butanol, pentanol, ethylene glycol, propylene glycol, 1,4-butanediol; acetone And ketones such as methyl ethyl ketone; esters such as ethyl acetate;

The absorption step is preferably performed in the temperature range of 0 ° C. to 60 ° C. with stirring for 5 minutes to 720 minutes. These conditions may be set as appropriate depending on the type of seed particles and monomers used, and these conditions may be used alone or in combination of two or more. In the absorption process, for determining whether the monomer component has been absorbed by the seed particles, for example, before adding the monomer component and after completion of the absorption step, observe the particles with a microscope and absorb the monomer component. It can be easily determined by confirming that the particle size is increased.

In the polymerization step, the monomer component absorbed by the seed particles is subjected to a polymerization reaction. Here, when the seed particles are a polymerizable polysiloxane, the absorbed monomer component and the radical polymerizable group of the polymerizable polysiloxane skeleton are polymerized to form a polysiloxane skeleton and a vinyl polymer. Combine. Although the polymerization method is not particularly limited, for example, a method using a radical polymerization initiator can be mentioned, and the radical polymerization initiator is not particularly limited. For example, a peroxide-based initiator, an azo-based initiator, etc. It can be used. These radical polymerization initiators may be used alone or in combination of two or more.

The reaction temperature for carrying out radical polymerization is preferably 40 ° C. or higher, more preferably 50 ° C. or higher, preferably 100 ° C. or lower, more preferably 80 ° C. or lower. If the reaction temperature is too low, the degree of polymerization does not increase sufficiently and the mechanical properties of the composite particles tend to be insufficient. On the other hand, if the reaction temperature is too high, aggregation between particles occurs during the polymerization. It tends to happen easily. The reaction time for performing radical polymerization may be appropriately changed according to the type of polymerization initiator to be used, but is usually preferably 5 minutes or more, more preferably 10 minutes or more, and preferably 600 minutes or less. More preferably, it is 300 minutes or less. When the reaction time is too short, the degree of polymerization may not be sufficiently increased, and when the reaction time is too long, aggregation tends to occur between particles.

The number-based average dispersed particle size of the resin particles after synthesis is preferably 1.1 μm or more, more preferably 1.2 μm or more, still more preferably 1.3 μm or more, and preferably 3.0 μm or less, more preferably 2 0.8 μm or less, more preferably 2.7 μm or less. The number-based variation coefficient of the dispersed particle diameter is preferably 10% or less, more preferably 9% or less, and still more preferably 7% or less.

The resin particles synthesized as described above are preferably subjected to classification so as to have a predetermined particle diameter, if necessary. The classification method is not particularly limited, for example, sieving with an electroforming sieve, etc .; filtration using a filter such as a membrane filter, a pleat filter, a ceramic membrane filter, etc .; a known apparatus for classification by the interaction of mass difference and fluid resistance difference ( Gravity classifier based on the principle of gravity difference such as particle fall velocity, (half) free vortex centrifugal classification based on the balance of centrifugal force and air drag by free vortex or semi-free vortex, rotating classification blade (rotor) Classification using a centrifugal classification with rotating blades based on the balance between the centrifugal force generated by the generated rotating flow and the drag force caused by air. Among these, classification using an electric sieve is preferable from the viewpoint of classification accuracy and productivity.

When classifying using an electroformed sieve, it is preferable to pass a dispersion in which resin particles are dispersed in a liquid medium through the electroformed sieve. Examples of the liquid medium include water; alcohols such as methanol, ethanol, propanol and butanol; hydrocarbons such as hexane and octane; aromatic hydrocarbons such as benzene, toluene and xylene; These may be used alone or in combination of two or more. Among these, alcohols and hydrocarbons are preferable, and methanol and hexane are more preferable. In order to improve the dispersibility of the resin particles, various dispersants may be added to the liquid medium.

The amount of the liquid medium used is preferably 100 parts by mass or more, more preferably 200 parts by mass or more, still more preferably 500 parts by mass or more, and preferably 10,000 parts by mass or less, relative to 100 parts by mass of the resin particles. Preferably it is 5000 mass parts or less, More preferably, it is 2000 mass parts or less. The method for dispersing the resin particles in the liquid medium is not particularly limited, for example, a method of dispersing by irradiating ultrasonic waves; a method of dispersing by a normal dispersing device, a high speed stirring device, a shearing dispersing device such as a colloid mill or a homogenizer, and the like. And the like.

The dispersion liquid temperature at the time of passing through the electroformed sieve is not particularly limited and may be appropriately adjusted according to the liquid medium to be used, but is usually 0 ° C. or higher and 100 ° C. or lower. The liquid temperature of the dispersion is naturally less than the boiling point of the liquid medium. What is necessary is just to change the dimension of the sieve hole of an electroforming sieve according to the desired average particle diameter and a coefficient of variation. By performing classification using an electric sieve, coarse particles can be removed, and the coefficient of variation of the particle diameter of the resin particles can be reduced.

After the synthesis, the resin particles classified as necessary are usually dried, and in some cases, subjected to the above-described firing (heat treatment). The heat treatment such as drying or baking may be performed according to a known method, but as described above, the silane-based crosslinkable monomer and the silane-based non-crosslinkable in the monomer component for forming the resin particles. When the monomer content exceeds a predetermined amount, it is important to limit the temperature in such heat treatment to less than 200 ° C.

The shape of the resin particles (base material) obtained as described above is not particularly limited, and may be any of, for example, a spherical shape, a spheroid shape, a confetti shape, a thin plate shape, a needle shape, an eyebrow shape, and the like. Spherical shape is preferable, but spherical shape is particularly preferable.

The conductive fine particles of the present invention have at least one conductive metal layer formed on the substrate (resin particle) surface. The metal constituting the conductive metal layer is not particularly limited. For example, gold, silver, copper, platinum, iron, lead, aluminum, chromium, palladium, nickel, rhodium, ruthenium, antimony, bismuth, germanium, tin, cobalt Indium, nickel-phosphorus, nickel-boron and other metals and metal compounds, and alloys thereof. Among these, gold, nickel, palladium, silver, copper, and tin are preferable because they become conductive fine particles having excellent conductivity. Also, in terms of inexpensiveness, nickel, nickel alloys (Ni—Au, Ni—Pd, Ni—Pd—Au, Ni—Ag); copper, copper alloys (Cu and Fe, Co, Ni, Zn, Sn, In, An alloy with at least one metal element selected from the group consisting of Ga, Tl, Zr, W, Mo, Rh, Ru, Ir, Ag, Au, Bi, Al, Mn, Mg, P, B, preferably Ag, Ni, Sn, Zn alloy); silver, silver alloy (Ag and Fe, Co, Ni, Zn, Sn, In, Ga, Tl, Zr, W, Mo, Rh, Ru, Ir, Au, Bi Alloy with at least one metal element selected from the group consisting of Al, Mn, Mg, P and B, preferably Ag—Ni, Ag—Sn, Ag—Zn; tin, tin alloy (eg Sn— Ag, Sn-Cu, Sn-Cu-Ag, Sn-Zn, Sn-S , Sn-Bi-Ag, Sn-Bi-In, Sn-Au, Sn-Pb, etc.) and the like are preferable.

The conductive metal layer is preferably composed of nickel or a nickel alloy, more preferably a nickel alloy, among the metals and alloys described above. In the present invention, the resin particles used as the base material are designed to be harder, thereby improving the indentation forming ability and obtaining the desired effect. In order to make this effect easier to express, the conductivity of the surface of the conductive fine particles is improved. It is desirable that the conductive metal layer has an appropriate hardness that can follow the substrate. If it is a metal layer comprised of nickel or a nickel alloy, it will have a hardness that is more suitable for exhibiting the effects of the present invention. From this point of view, the nickel alloy constituting the conductive metal layer is particularly a Ni alloy (Ni—P alloy, Ni—B alloy, Ni) containing at least one of phosphorus (P) and boron (B) as an alloy component. -PB alloy), more preferably an alloy containing phosphorus (P). By containing phosphorus (P) and boron (B), the nickel alloy becomes soft and the conductive metal layer easily follows the base material.

When the nickel alloy constituting the conductive metal layer contains phosphorus (P) or boron (B), the total content of phosphorus (P) and boron (B) is 100 masses in total of Ni, P, and B in the alloy. % Is preferably 4% by mass or more, more preferably 5% by mass or more, and still more preferably 6% by mass or more. The content of phosphorus (P) alone is preferably 4% by mass or more, more preferably 5% by mass or more, and further preferably 6% by mass or more with respect to the total of 100% by mass of Ni, P, and B in the alloy. is there. The content of boron (B) alone is preferably 4% by mass or more, more preferably 5% by mass or more, and further preferably 6% by mass or more with respect to the total of 100% by mass of Ni, P and B in the alloy. is there. The greater the content of phosphorus (P) and boron (B), the softer the nickel alloy, and the more easily the effects of the present invention are exhibited. However, if the content of phosphorus (P) or boron (B) in the nickel alloy is too large, the electrical resistance value of the conductive metal layer may increase. Therefore, the total content of phosphorus (P) and boron (B) in the nickel alloy is preferably 15% by mass or less when the total mass of Ni, P, and B in the alloy is 100% by mass, for the same reason. Therefore, the P content in the nickel alloy is preferably 15% by mass or less, and the B content in the nickel alloy is preferably 10% by mass or less. The P content and B content in the nickel alloy can be controlled by adjusting the P concentration, B concentration, pH, etc. of the electroless nickel plating solution used when forming the conductive metal layer.

In addition, the nickel alloy which comprises a conductive metal layer may contain other metal components other than phosphorus (P) and boron (B). As the other metal component, a hardly oxidizable metal element such as Au or Pd is preferable because it does not impair the effect of the nickel alloy.

The conductive metal layer may be a single layer or multiple layers. In the case of multiple layers, for example, nickel (nickel alloy) -gold, nickel (nickel alloy) -palladium, nickel (nickel alloy) ) -Palladium-gold, nickel (nickel alloy) -silver and the like are preferred.

The thickness of the conductive metal layer is preferably 0.01 μm or more, more preferably 0.03 μm or more, further preferably 0.05 μm or more, preferably 0.20 μm or less, more preferably 0.18 μm or less, More preferably, it is 0.15 micrometer or less, More preferably, it is 0.12 micrometer or less, Most preferably, it is 0.080 micrometer or less. In the conductive fine particles of the present invention in which the resin particles as the base material have a fine particle diameter, when the conductive metal layer has a thickness within the above range, the conductive fine particles are used as an anisotropic conductive material. Stable electrical connection can be maintained.

The method for forming the conductive metal layer is not particularly limited, for example, a method in which the surface of the substrate is plated by an electroless plating method, an electrolytic plating method, or the like; physical properties such as vacuum deposition, ion plating, ion sputtering on the surface of the substrate A method of forming a conductive metal layer by a general vapor deposition method; Among these, the electroless plating method is particularly preferable in that a conductive metal layer can be easily formed without requiring a large-scale apparatus.

The conductive metal layer only needs to cover at least a part of the surface of the resin particles, but the surface of the conductive metal layer has no substantial cracks or conductive metal layer. Is preferably absent. Here, “substantially cracked or a surface on which no conductive metal layer is formed” means that when the surface of any 10,000 conductive fine particles is observed using an electron microscope (magnification 1000 times), It means that the crack of the conductive metal layer and the exposure on the surface of the resin particles are not substantially visually observed.

The conductive metal layer is preferably smooth and has no protrusions. Specifically, the number of protrusions having a height of 0.05 μm or more from the surface of the conductive metal layer is preferably less than 10 per conductive fine particle, and more preferably less than 5. It is particularly preferable that the number is less than 2. Here, the protruding portion is made of the same metal or alloy as the conductive metal layer, and means a portion where the conductive metal layer and the metal or alloy constituting the protruding portion are integrated. . If there is a protrusion integrated with the same metal or alloy as the conductive metal layer, the protrusion may become the starting point of the crack, causing the metal layer to break and the resistance value during electrical connection to increase. . Further, it is preferable that the conductive metal layer does not have metal fine particles due to abnormal precipitation, or even if it has adhered, the number of adhesion is small. Specifically, the number of metal fine particles attached is preferably less than 2 per conductive fine particle.

The number average particle diameter of the conductive fine particles of the present invention is preferably 1.1 μm or more, more preferably 1.2 μm or more, further preferably 1.3 μm or more, particularly preferably 1.4 μm or more, and 2.8 μm or less. Is preferably 2.6 μm or less, more preferably 2.4 μm or less, and particularly preferably 2.2 μm or less. If the number average particle diameter is within this range, it can be suitably used for electrical connection of miniaturized and narrowed electrodes and wirings.
The number average particle size of the conductive fine particles was determined using a flow type particle image analyzer (“FPIA (registered trademark) -3000” manufactured by Sysmex Corporation), and the average particle size based on the number of 3000 particles. Is preferably adopted.

The conductive fine particles of the present invention preferably have a compressive elastic modulus (10% K value) of 12,000 N / mm ² or more and 200,000 N / mm ² or less when the diameter is displaced by 10%. More preferably 14,000N / mm ² or more, more preferably 15,000N / mm ² or more, more preferably 17,000N / mm ² or more, more preferably 20000 N / mm ² or more, more preferably 150 , N / mm ² or less, more preferably 100,000 N / mm ² or less, and most preferably 75,000 N / mm ² or less. If the 10% K value of the conductive fine particles is within this range, a sufficient indentation can be formed on the connected body (electrode), thereby improving the adhesion between the conductive metal layer and the connected body, It is possible to secure a connection area. The 10% K value of the conductive fine particles can be measured in the same manner as the 10% K value of the resin particles.

The conductive fine particles of the present invention can also have an insulating resin layer on at least a part of the surface. That is, the aspect which provided the insulating resin layer further on the surface of the said electroconductive metal layer may be sufficient. When the insulating resin layer is further laminated on the conductive metal layer on the surface in this way, it is possible to prevent the lateral conduction that is likely to occur when a high-density circuit is formed or when a terminal is connected.

The insulating resin layer is not particularly limited as long as the insulating property between the particles of the conductive fine particles can be secured, and the insulating resin layer can be easily collapsed or peeled off by a certain pressure and / or heating. For example, polyolefins such as polyethylene; (meth) acrylate polymers and copolymers such as polymethyl (meth) acrylate; thermoplastic resins such as polystyrene; and cross-linked products thereof; epoxy resins, phenol resins, amino resins (melamine resins, etc.) And the like; and water-soluble resins such as polyvinyl alcohol and mixtures thereof. However, when the insulating resin layer is too hard compared to the base particle, the base particle itself may be destroyed before the insulating resin layer is destroyed. Therefore, it is preferable to use an uncrosslinked or relatively low degree of crosslinking resin for the insulating resin layer.

The insulating resin layer may be a single layer or a plurality of layers. For example, a single or a plurality of film-like layers may be formed, or a layer in which particles having insulating, granular, spherical, lump, scale or other shapes are attached to the surface of the conductive metal layer. Further, it may be a layer formed by chemically modifying the surface of the conductive metal layer, or a combination thereof. The thickness of the insulating resin layer is preferably 0.01 μm or more and 1 μm or less, more preferably 0.02 μm or more and 0.5 μm or less, and further preferably 0.03 μm or more and 0.4 μm or less. When the thickness of the insulating resin layer is within the above range, the electrical insulation between the particles becomes good while maintaining the conduction characteristics by the conductive particles.

2. Anisotropic conductive material The anisotropic conductive material of the present invention comprises the conductive fine particles of the present invention dispersed in a binder resin. The form of the anisotropic conductive material is not particularly limited, and examples thereof include various forms such as an anisotropic conductive film, an anisotropic conductive paste, an anisotropic conductive adhesive, and an anisotropic conductive ink. By providing these anisotropic conductive materials between opposing substrates or between electrode terminals, good electrical connection can be achieved. The anisotropic conductive material using the conductive fine particles of the present invention includes a conductive material for a liquid crystal display element (conductive spacer and composition thereof).

The binder resin is not particularly limited as long as it is an insulating resin, and examples thereof include thermoplastic resins such as acrylic resins, ethylene-vinyl acetate resins, styrene-butadiene block copolymers; monomers and oligomers having a glycidyl group; Examples thereof include a curable resin composition that is cured by a reaction with a curing agent such as isocyanate; a curable resin composition that is cured by light or heat;
The anisotropic conductive material of the present invention can be obtained by dispersing the conductive fine particles of the present invention in the binder resin to obtain a desired form. For example, the binder resin and the conductive fine particles are separately provided. You may connect by making electroconductive fine particles exist with a binder resin between the base material to be used and connecting between electrode terminals.

In the anisotropic conductive material of the present invention, the content of the conductive fine particles may be appropriately determined according to the use. For example, the volume of the anisotropic conductive material is preferably 1% by volume or more, more preferably Is 2% by volume or more, more preferably 5% by volume or more, preferably 50% by volume or less, more preferably 30% by volume or less, and still more preferably 20% by volume or less. If the content of the conductive fine particles is too small, it may be difficult to obtain sufficient electrical continuity. On the other hand, if the content of the conductive fine particles is too large, the conductive fine particles are in contact with each other, and anisotropy is caused. The function as a conductive material may be difficult to be exhibited.

About the film thickness in the anisotropic conductive material of the present invention, the coating thickness of the paste or adhesive, the printed film thickness, etc., the particle diameter of the conductive fine particles of the present invention to be used and the specifications of the electrode to be connected In consideration of the above, it is preferable to appropriately set so that the conductive fine particles are sandwiched between the electrodes to be connected and the gap between the bonding substrates on which the electrodes to be connected are formed is sufficiently filled with the binder resin layer. .

The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to the following examples, and may be appropriately modified and implemented within a range that can meet the purpose described above and below. All of which are within the scope of the present invention. In the following, “part” means “part by mass” and “%” means “mass%” unless otherwise specified.

1. Physical property measurement method Various physical properties were measured by the following methods.
<Average dispersed particle size of seed particles and resin particles>
20 parts of a 1% aqueous solution of polyoxyethylene alkyl ether sulfate ammonium salt (Daiichi Kogyo Seiyaku Co., Ltd. “Hitenol (registered trademark) N-08”) as an emulsifier is added to 0.005 part of resin particles. After being dispersed for 10 minutes by sonic waves, the particle size (μm) of 30000 particles was measured using a particle size distribution analyzer (“Coulter Multisizer III type” manufactured by Beckman Coulter, Inc.), and the number-based average dispersed particles The diameter was determined.

<Number average particle diameter of conductive fine particles>
After adding 17.5 parts of 1.4% aqueous solution of polyoxyethylene oleyl ether (“Emulgen 430” manufactured by Kao Corporation) as an emulsifier to 0.05 parts of conductive fine particles and dispersing for 10 minutes with ultrasound, Using a flow particle image analyzer (“FPIA (registered trademark) -3000” manufactured by Sysmex Corporation), the particle diameter (μm) of 3000 particles was measured to determine the number average particle diameter.

<Film thickness of conductive metal layer>
Using a flow type particle image analyzer (“FPIA (registered trademark) -3000” manufactured by Sysmex Corporation), the number average particle diameter X (μm) of 3000 base particles (resin particles) and the number of 3000 conductive fine particles The average particle size Y (μm) was measured. And the film thickness of the electroconductive metal layer was computed according to the following formula.
Conductive metal layer thickness (μm) = (Y−X) / 2

<Phosphorus (P) content of conductive metal layer>
The conductive metal layer (plating film) of the conductive fine particles is dissolved using aqua regia and analyzed with an inductively coupled plasma emission spectrometer (ICP) (“ICPE-9000” manufactured by Shimadzu Corporation). The Ni mass and the P mass contained per 1 g of the conductive metal layer were determined from the results, and the P content (%) was calculated based on the following formula. Note that none of the conductive metal layers formed in the following examples contain boron (B).
P content (% by mass) = P mass × 100 / (Ni mass + P mass)

<10% to 40% K value and compressive fracture deformation rate of resin particles>
Using a micro-compression tester (“MCT-W500” manufactured by Shimadzu Corporation), a circular flat plate indenter with a diameter of 50 μm is used for one particle dispersed on a sample table (material: SKS flat plate) at room temperature (25 ° C.). Using (material: diamond), a load was applied at a constant load speed (2.2295 mN / sec) toward the center of the particles in the “standard surface detection” mode. Then, the load (mN) when the compression displacement became 10%, 20%, 30%, and 40% of the particle diameter, and the displacement amount (μm) when the particles were broken by deformation were measured. The K value was calculated from the obtained compressive load, the compression displacement of the particles, and the particle diameter. In addition, the measurement was performed on 10 different particles for each sample, and the average value was used as the measurement value.

2. 2. Production of conductive fine particles 2-1. Preparation of substrate particles (resin particles) (Production Example 1)
In a four-necked flask equipped with a condenser, a thermometer, and a dripping port, 1800 parts of ion-exchanged water, 24 parts of 25% aqueous ammonia, and 600 parts of methanol are placed under stirring and a polymerizable silane compound (simple 40 parts of 3-methacryloxypropyltrimethoxysilane (MPTMS) is added as a monomer component), and hydrolysis and condensation reactions of 3-methacryloxypropyltrimethoxysilane are carried out to produce polysiloxane particles having methacryloyl groups (seed particles). ) Emulsion was prepared. The number-based average dispersed particle size of the polysiloxane particles was 0.94 μm.

Next, 3.0 parts of a 20% aqueous solution of polyoxyethylene styrenated phenyl ether sulfate ammonium salt (“Hitenol (registered trademark) NF-08” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an emulsifier is dissolved in 120 parts of ion-exchange water. In this solution, 60 parts of styrene (St) and 60 parts of 1,6-hexanediol dimethacrylate (HXDMA) as absorption monomers (monomer components) and 2,2′-azobis (2,4-dimethylvaleronitrile) A solution in which 1.6 parts (Wako Pure Chemical Industries, Ltd. “V-65”) was dissolved was added and emulsified and dispersed to prepare an emulsion of an absorbing monomer. Two hours after the start of emulsification dispersion, the obtained emulsion was added to an emulsion of polysiloxane particles (seed particles), and further stirred. One hour after the addition of the emulsified liquid, the mixed liquid was sampled and observed with a microscope. As a result, it was confirmed that the polysiloxane particles were absorbed and absorbed.

Next, 8.0 parts of a 20% aqueous solution of polyoxyethylene styrenated phenyl ether sulfate ammonium salt was added, and the reaction solution was heated to 65 ° C. under a nitrogen atmosphere and held at 65 ° C. for 2 hours. The components were radically polymerized. The emulsion after radical polymerization was subjected to solid-liquid separation, and the obtained cake was washed with ion-exchanged water and methanol, and then vacuum-dried at 120 ° C. for 2 hours in a nitrogen atmosphere to obtain resin particles (1). Table 1 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value, and compression fracture deformation rate of the obtained resin particles.

(Production Example 2)
Manufactured except that the type and amount (parts by mass) of the absorbing monomer were changed as shown in Table 1, and the resin particles obtained by drying were further heat-treated at 280 ° C. for 1 hour in a nitrogen atmosphere. Resin particles (2) were produced in the same manner as in Example 1. Table 1 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value, and compression fracture deformation rate of the obtained resin particles.

(Production Example 3)
In preparing the polysiloxane particle emulsion, the resin particles (3) were prepared in the same manner as in Production Example 2 except that the amount of ion exchange water was changed to 1750 parts and the amount of methanol used was changed to 650 parts. Produced. At this time, the average dispersed particle size based on the number of polysiloxane particles in the polysiloxane particle emulsion was 1.17 μm. Table 1 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value, and compression fracture deformation rate of the obtained resin particles.

(Production Example 4)
Resin particles (4) were produced in the same manner as in Production Example 1 except that the type and amount (parts by mass) of the absorbing monomer were changed as shown in Table 1. Table 1 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value, and compression fracture deformation rate of the obtained resin particles.

(Production Example 5)
Resin particles (in the same manner as in Production Example 1) except that the type and amount (parts by mass) of the absorbing monomer were changed as shown in Table 1 and were dried in vacuum at 80 ° C. for 12 hours in a nitrogen atmosphere. 5) was produced. Table 1 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value, and compression fracture deformation rate of the obtained resin particles.

(Production Example 6)
While changing the kind and amount (parts by mass) of the polymerizable silane compound and the absorption monomer as shown in Table 1, the resin particles obtained by drying were further subjected to heat treatment at 320 ° C. for 1 hour in a nitrogen atmosphere. Except for this, resin particles (6) were produced in the same manner as in Production Example 1. Table 1 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value, and compression fracture deformation rate of the obtained resin particles.

(Production Example 7)
Resin particles (7) were obtained in the same manner as in Production Example 6 except that the heat treatment was not performed. Table 1 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value, and compression fracture deformation rate of the obtained resin particles.

(Production Example 8)
Manufactured except that the type and amount (parts by mass) of the absorbing monomer were changed as shown in Table 1, and the resin particles obtained by drying were further heat-treated at 280 ° C. for 1 hour in a nitrogen atmosphere. Resin particles (8) were produced in the same manner as in Example 1. Table 1 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value, and compression fracture deformation rate of the obtained resin particles.

(Production Example 9)
In preparing the polysiloxane particle emulsion, resin particles (9) were prepared in the same manner as in Production Example 8 except that the amount of ion-exchanged water was changed to 2100 parts and the amount of methanol used was changed to 300 parts. Produced. At this time, the average dispersed particle size based on the number of polysiloxane particles in the polysiloxane particle emulsion was 0.83 μm. Table 1 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value, and compression fracture deformation rate of the obtained resin particles.

(Production Example 10)
Manufactured except that the type and amount (parts by mass) of the absorbing monomer were changed as shown in Table 1, and the resin particles obtained by drying were further heat-treated at 280 ° C. for 1 hour in a nitrogen atmosphere. Resin particles (10) were produced in the same manner as in Example 1. Table 1 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value, and compression fracture deformation rate of the obtained resin particles.

(Production Example 11)
Resin particles (11) were obtained in the same manner as in Production Example 10 except that the heat treatment was not performed. Table 1 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value, and compression fracture deformation rate of the obtained resin particles.

(Production Example 12)
In preparing the polysiloxane particle emulsion, the resin particles (12) were prepared in the same manner as in Production Example 10 except that the amount of ion-exchanged water was changed to 2100 parts and the amount of methanol used was changed to 300 parts. Produced. At this time, the average dispersed particle size based on the number of polysiloxane particles in the polysiloxane particle emulsion was 0.83 μm. Table 1 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value, and compression fracture deformation rate of the obtained resin particles.

(Production Example 13)
Resin particles (13) were produced in the same manner as in Production Example 1, except that the type and amount (parts by mass) of the absorbing monomer were changed as shown in Table 2. Table 2 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value and compression fracture deformation rate of the obtained resin particles.

(Production Example 14)
Resin particles (14) were produced in the same manner as in Production Example 1 except that the type and amount (parts by mass) of the absorbing monomer were changed as shown in Table 2. Table 2 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value and compression fracture deformation rate of the obtained resin particles.

(Production Example 15)
Manufactured except that the type and amount (parts by mass) of the absorbing monomer were changed as shown in Table 2, and the resin particles obtained by drying were further heat-treated at 230 ° C. for 1 hour in a nitrogen atmosphere. Resin particles (15) were produced in the same manner as in Example 1. Table 2 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value and compression fracture deformation rate of the obtained resin particles.

(Production Example 16)
Resin particles (16) were obtained in the same manner as in Production Example 15 except that the heat treatment was not performed. Table 2 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value and compression fracture deformation rate of the obtained resin particles.

(Production Example 17)
Manufactured except that the type and amount (parts by mass) of the absorbing monomer were changed as shown in Table 2, and the resin particles obtained by drying were further heat-treated at 230 ° C. for 1 hour in a nitrogen atmosphere. Resin particles (17) were produced in the same manner as in Example 1. Table 2 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value and compression fracture deformation rate of the obtained resin particles.

(Production Example 18)
Manufacture except that the type and amount (parts by mass) of the absorbing monomer were changed as shown in Table 2, and the resin particles obtained by drying were further heat-treated at 300 ° C. for 1 hour in a nitrogen atmosphere. Resin particles (18) were produced in the same manner as in Example 1. Table 2 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value and compression fracture deformation rate of the obtained resin particles.

(Production Example 19)
Resin particles (19) were obtained in the same manner as in Production Example 18 except that the heat treatment was not performed. Table 2 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value and compression fracture deformation rate of the obtained resin particles.

(Production Example 20)
Manufactured except that the type and amount (parts by mass) of the absorbing monomer were changed as shown in Table 2, and the resin particles obtained by drying were further heat-treated at 230 ° C. for 1 hour in a nitrogen atmosphere. Resin particles (20) were produced in the same manner as in Example 1. Table 2 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value and compression fracture deformation rate of the obtained resin particles.

(Production Example 21)
Manufactured except that the type and amount (parts by mass) of the absorbing monomer were changed as shown in Table 2, and the resin particles obtained by drying were further heat-treated at 230 ° C. for 1 hour in a nitrogen atmosphere. Resin particles (21) were produced in the same manner as in Example 1. Table 2 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value and compression fracture deformation rate of the obtained resin particles.

(Production Example 22)
In preparing the polysiloxane particle emulsion, the amount of ion-exchanged water used was changed to 1600 parts, the amount of methanol used was changed to 800 parts, and the type and amount (parts by weight) of the absorbing monomer are shown in Table 2. Resin particles (22) were produced in the same manner as in Production Example 1 except for the above changes. At this time, the average dispersed particle size based on the number of polysiloxane particles in the polysiloxane particle emulsion was 1.43 μm. Table 2 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value and compression fracture deformation rate of the obtained resin particles.

(Production Example 23)
In a solution obtained by dissolving 10 parts of a 20% aqueous solution of polyoxyethylene styrenated phenyl ether sulfate ammonium salt (Daiichi Kogyo Seiyaku "Hytenol (registered trademark) NF-08") as an emulsifier in 300 parts of ion-exchanged water, A monomer component comprising 50 parts of 1,9-nonanediol dimethacrylate and 50 parts of styrene and 2,2′-azobis (2,4-dimethylvaleronitrile) (“V-65” manufactured by Wako Pure Chemical Industries, Ltd.) A mixed solution with 2.0 parts was added and emulsified and dispersed to prepare an emulsion of monomer components. The obtained emulsified liquid is put into a four-necked flask equipped with a condenser, a thermometer, and a dripping port, diluted by adding 500 parts of ion-exchanged water, and then heated to 65 ° C. in a nitrogen atmosphere. The mixture was held at 65 ° C. for 2 hours to perform radical polymerization of the monomer component. The emulsion after radical polymerization is subjected to solid-liquid separation, and the resulting cake is washed with ion-exchanged water and methanol, and then wet classification is repeated, followed by vacuum drying at 120 ° C. for 2 hours to produce resin particles (23). did. Table 3 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value and compression fracture deformation rate of the obtained resin particles.

(Production Example 24)
Resin particles (24) were produced in the same manner as in Production Example 23, except that the monomer component was changed to 100 parts of 1,9-nonanediol dimethacrylate. Table 3 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value and compression fracture deformation rate of the obtained resin particles.

(Production Example 25)
Production examples except that the monomer components were changed to 75 parts of trimethylolpropane triacrylate and 25 parts of divinylbenzene (“DVB960” manufactured by Nippon Steel Chemical Co., Ltd .: 96% divinylbenzene, 4% ethylvinylbenzene). In the same manner as in No. 23, resin particles (25) were produced. Table 3 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value and compression fracture deformation rate of the obtained resin particles.

(Production Example 26)
Resin particles (26) were produced in the same manner as in Production Example 23, except that the monomer components were changed to 40 parts ethylene glycol dimethacrylate, 40 parts styrene, and 20 parts t-butyl methacrylate. Table 3 shows the average dispersed particle size, 10% K value, 20% K value, 30% K value, 40% K value and compression fracture deformation rate of the obtained resin particles.

2-2. Production of conductive fine particles (formation of conductive metal layer)
Example 1
The resin particles (1) used as a base material are subjected to etching treatment with sodium hydroxide, then sensitized by contacting with a tin dichloride solution, and then activated by immersing in a palladium dichloride solution. Palladium nuclei were formed by the method (sensitizing-activation method). Next, 2 parts of resin particles with palladium nuclei formed were added to 400 parts of ion-exchanged water, and after ultrasonic dispersion treatment, the resulting resin particle suspension was heated in a 70 ° C. hot bath. By adding 600 parts of electroless plating solution (“Schumar S680” manufactured by Nippon Kanisen Co., Ltd.) separately heated to 70 ° C. with the suspension heated in this way, an electroless nickel plating reaction occurs. I let you. After confirming that the generation of hydrogen gas was completed, solid-liquid separation was performed, followed by washing with ion-exchanged water and methanol in that order, and vacuum drying at 100 ° C. for 2 hours to obtain nickel-plated particles. Next, the obtained nickel plating particles were added to a displacement gold plating solution containing potassium gold cyanide, and gold plating was further performed on the surface of the nickel layer to obtain conductive fine particles. The film thickness of the conductive metal layer in the obtained conductive fine particles was as shown in Table 4.

(Examples 2 to 20 and Comparative Examples 1 to 2)
Conductive fine particles were produced in the same manner as in Example 1 except that the resin particles shown in Table 4 or 5 were used as the substrate. The film thickness of the conductive metal layer in the obtained conductive fine particles was as shown in Table 4 or Table 5.

(Example 21)
Resin particles (23) are used as the base material, and the electroless plating solution has a nickel sulfate hexahydrate concentration of 50 g / L, a sodium hypophosphite monohydrate concentration of 20 g / L, and a sodium citrate concentration of 50 g. / L, and conductive fine particles were produced in the same manner as in Example 1 except that an electroless nickel plating solution whose pH was adjusted to 7.5 with an aqueous sodium hydroxide solution was used. The film thickness and phosphorus content of the conductive metal layer in the obtained conductive fine particles were as shown in Table 6.

(Example 22)
Conductive fine particles were produced in the same manner as in Example 21 except that the resin particles (24) were used as the base material. The film thickness and phosphorus content of the conductive metal layer in the obtained conductive fine particles were as shown in Table 6.

(Example 23)
Conductive fine particles were produced in the same manner as in Example 21 except that the resin particles (25) were used as the substrate. The film thickness and phosphorus content of the conductive metal layer in the obtained conductive fine particles were as shown in Table 6.

(Example 24)
Conductive fine particles were produced in the same manner as in Example 21 except that the resin particles (26) were used as the base material. The film thickness and phosphorus content of the conductive metal layer in the obtained conductive fine particles were as shown in Table 6.

(Example 25)
Conductive fine particles were produced in the same manner as in Example 21 except that the resin particles (26) were used as the base material and the pH value of the electroless plating solution was changed to 11.0 (adjusted with an aqueous sodium hydroxide solution). . The film thickness and phosphorus content of the conductive metal layer in the obtained conductive fine particles were as shown in Table 6.

3. Production and Evaluation of Anisotropic Conductive Material Using the conductive fine particles obtained in each Example and Comparative Example, an anisotropic conductive material (anisotropic conductive film) was produced by the following method, and the performance was The method was evaluated.
That is, 1 part of conductive fine particles, 100 parts of an epoxy resin (“JER828” manufactured by Mitsubishi Chemical) as a binder resin, and 2 parts of a curing agent (“Sun Aid (registered trademark) SI-150” manufactured by Sanshin Chemical Co., Ltd.) 100 parts of toluene was added, 50 parts of zirconia beads having a diameter of 1 mm were further added, and the mixture was stirred and dispersed at 300 rpm for 10 minutes using two stainless steel stirring blades. And the anisotropic conductive film was obtained by apply | coating and drying the obtained paste-form composition on PET film which gave the peeling process with the bar coater.

The obtained anisotropic conductive film was sandwiched between an entire aluminum vapor-deposited glass substrate having resistance measurement lines and a polyimide film substrate having a copper pattern formed on a 20 μm pitch, and two pressures (high pressure: 7 MPa). The connection structure (high-pressure connection structure and low-pressure connection structure) was produced by pressure bonding at 185 ° C. under a low pressure of 2 MPa.
Then, the initial resistance value A between the electrodes of the obtained connection structure is measured. When the initial resistance value A is less than 3Ω, “◎”, when it is 3Ω or more and 5Ω or less, “◯”, when it exceeds 5Ω. “×” was evaluated. In addition, the surface of the electrode on the side in contact with the anisotropic conductive film after low-pressure (2 MPa) pressure bonding was observed with a metal microscope (magnification: 1000 times). Was evaluated as “×”.

Furthermore, after the obtained low-pressure connection structure was left in an atmosphere of 85 ° C. and 85% RH for 500 hours, the resistance value B was measured in the same manner as the initial resistance value A, and the resistance value increase rate ( %). A case where the rate of increase in resistance value (%) was 1% or less was evaluated as “◎”, a case where it exceeded 1% and 3% or less was evaluated as “◯”, and a case where it exceeded 3% was evaluated as “X”.
Resistance value increase rate (%) = [(BA) / A] × 100

In Table 1, Table 2, and Table 3, the following abbreviations were used.
MPTMS: 3-methacryloxypropyltrimethoxysilane (“KBM503” manufactured by Shin-Etsu Silicone)
VTMS: Vinyltrimethoxysilane (“KBM1003” manufactured by Shin-Etsu Silicone)
St: styrene HXDMA: 1,6-hexanediol dimethacrylate DVB: divinylbenzene (“DVB960” manufactured by Nippon Steel Chemical Co., Ltd .: a product containing 96% divinylbenzene and 4% ethylvinylbenzene; The numerical value described as is the amount of “DVB960” actually used, and the numerical value described as the composition is a value calculated based on divinylbenzene contained substantially.
TMP-3EO-A: Trimethylolpropane EO modified (3 mol) triacrylate TMP-6EO-A: Trimethylolpropane EO modified (6 mol) triacrylate HXDA :: 1,6-hexanediol diacrylate MPMDMS: 3-methacrylic Roxypropylmethyldimethoxysilane (“KBM502” manufactured by Shin-Etsu Silicone)
1,9-ND: 1,9-nonanediol dimethacrylate TMP-A: trimethylolpropane triacrylate EGDMA :: ethylene glycol dimethacrylate tBMA: t-butyl methacrylate

The conductive fine particles of the present invention are suitably used for anisotropic conductive materials such as anisotropic conductive films, anisotropic conductive pastes, anisotropic conductive adhesives, anisotropic conductive inks, and the like.

Claims (12)

1. Conductive fine particles having a base material composed of resin particles and at least one conductive metal layer formed on the surface of the base material,
   The average dispersed particle diameter based on the number of the resin particles is 1.0 μm to 2.5 μm, and the compressive elastic modulus (10% K value) when the diameter of the resin particles is displaced by 10% is 12,000 N / mm ^2. Conductive fine particles characterized by the above.
2. The number-based average dispersed particle diameter of the resin particles is 2.0 μm or more, and the compression modulus (10% K value) when the diameter of the resin particles is displaced by 10% is 17,000 N / mm ² or more. The conductive fine particles according to claim 1.
3. The number-based average dispersed particle diameter of the resin particles is less than 2.0 μm, and the compressive elastic modulus (10% K value) when the diameter of the resin particles is displaced by 10% is more than 19,600 N / mm ^2. The conductive fine particles according to claim 1.
4. The conductive fine particles according to any one of claims 1 to 3, wherein the resin particles have a compressive fracture deformation rate of 30% or more.
5. 5. The conductive fine particles according to claim 1, wherein a compression elastic modulus (30% K value) when the diameter of the resin particles is displaced by 30% is smaller than the 10% K value.
6. 6. The conductive fine particles according to claim 1, which have an insulating resin layer on at least a part of the surface.
7. Particles used as a base material for conductive fine particles,
   The number-based average dispersed particle diameter is 1.0 μm to 2.5 μm, and the compressive elastic modulus (10% K value) when the particle diameter is displaced by 10% is 12,000 N / mm ² or more. Resin particles.
8. 8. The number-based average dispersed particle diameter is 2.0 μm or more, and the compression elastic modulus (10% K value) when the particle diameter is displaced by 10% is 17,000 N / mm ² or more. Resin particles.
9. 8. The number-based average dispersed particle diameter is less than 2.0 μm, and the compression elastic modulus (10% K value) when the particle diameter is displaced by 10% is more than 19,600 N / mm ² . Resin particles.
10. The resin particle according to any one of claims 7 to 9, having a compression fracture deformation rate of 30% or more.
11. The resin particles according to any one of claims 7 to 10, wherein a compression elastic modulus (30% K value) when the particle diameter is displaced by 30% is smaller than the 10% K value.
12. An anisotropic conductive material comprising the conductive fine particles according to any one of claims 1 to 6 dispersed in a binder resin.