JP5583712B2 - Conductive fine particles and anisotropic conductive material using the same - Google Patents

Description

  The present invention relates to fine conductive fine particles, and particularly relates to conductive fine particles that can suppress an increase in resistance value over time and maintain good connection reliability over a long period of time.

  2. Description of the Related Art Conventionally, in assembling electronic devices, a connection method using an anisotropic conductive material has been adopted to make electrical connection between a large number of opposing electrodes and wirings. 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, electronic devices have been increasingly reduced in size and functionality. Along with this, electronic components mounted on electronic devices have been miniaturized and high-density mounting has progressed, and electrodes and wirings in electronic circuits are becoming finer and narrower. Therefore, the conductive fine particles used for the anisotropic conductive material are also required to have a smaller particle diameter.

  As the conductive fine particles having a small particle diameter, for example, microspheres made of a resin or an inorganic compound and having an average particle diameter of 0.5 to 2.5 μm and a CV value of the particle diameter 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, conductive particles having a particle diameter of 1 to 2 μm are disclosed (Patent Document 2).

JP 2000-30526 A JP 2003-323813 A

  However, when conventional conductive particles having a small particle diameter are used for electrical connection, the resistance value may increase with time even if the resistance value is sufficiently low at the initial stage of connection. . This is presumably because the smaller the particle diameter, the more easily affected by the connection environment (temperature, humidity, etc.).

  The present invention has been made in view of the above circumstances, and although it is a fine conductive fine particle, when it is subjected to electrical connection, it suppresses an increase in resistance value over time and has good connection reliability over a long period of time. It is an object to provide conductive fine particles capable of maintaining the above and an anisotropic conductive material using the same.

  The present inventors have intensively studied to solve the above problems. As a result, in order to realize electrical connection with high connection reliability, a method of increasing the connection reliability by forming a sufficient indentation by applying pressure using conductive fine particles having high hardness can be considered. In the case of particle size, in order to reduce the adverse effects (specifically, the decrease in connection reliability such as an increase in resistance) caused by exposure to harsh environments such as high temperature and high humidity after connection, on the contrary, it is somewhat soft. In addition, the inventors have found that particles having such a repulsive force have an advantageous effect on connection reliability. Then, a soft and repulsive resin particle having a specific range of compression elastic modulus (10% K value) when the particle diameter is displaced by 10% and particle compression deformation recovery rate is a base material of conductive fine particles. Then, in addition to the sufficiently low resistance value at the initial stage of connection, it was found that the increase in resistance value over time can be suppressed, and the present invention has been completed.

That is, the conductive fine particles according to the present invention are 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, and the average of the resin particles When the particle diameter is 1.0 μm to 2.5 μm and the diameter of the resin particle is displaced by 10%, the compression modulus (10% K value) is 6,000 N / mm ² or more and 20,000 N / mm ² or less. The compression deformation recovery rate of the resin particles is 40% or more.
In the conductive fine particles of the present invention, the compression elastic modulus (30% K value) when the diameter of the resin particles is displaced by 30% is preferably 25,000 N / mm ² or less, and 15,000 N / mm. More preferably, it is ² or less. Further, the compression deformation recovery rate is preferably 50% or more. Moreover, in this invention, the monomer component which comprises the said resin particle is a monomer component total amount 100 at least one of the specific crosslinkable monomer (a) mentioned later and a specific crosslinkable monomer (b). It is preferable to contain 50 mass% or more in mass%.
The anisotropic conductive material according to the present invention is characterized in that the conductive fine particles of the present invention are dispersed in a binder resin.

  According to the conductive fine particles of the present invention, it is possible to suppress a rise in resistance value with time and maintain good connection reliability over a long period of time when subjected to electrical connection while being fine conductive fine particles. Is possible. Thereby, the effect that the electrical connection of the refined | miniaturized and narrowed electrode and wiring can be performed favorably is acquired.

1. Resin particles (base material)
The conductive fine particles of the present invention are composed of resin particles as a base material and at least one conductive metal layer formed on the surface of the base material.
The average particle diameter of the resin particles is a number-based average dispersed particle diameter of 1.0 μm or more, preferably 1.1 μm or more, more preferably 1.2 μm or more, and further preferably 1.3 μm or more. It is 5 μm or less, preferably 2.3 μm or less, more preferably 2.1 μm or less, and even more preferably 1.9 μm or less. The present invention aims to improve fine conductive fine particles, and if the average particle diameter of the resin particles (base material) is within the above range, fine conductive fine particles can be obtained and refined and narrowed. It can be suitably used for electrical connection of the formed electrodes and wiring.

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, the resin particles are preferably those from which coarse particles have been removed. If coarse base particles are present, after forming a conductive metal layer, the coarse particles settle when stored as an anisotropic conductive material for a long period of time, causing aggregation of conductive fine particles. There is a fear. 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. . The particle diameter at the integrated value of 90% means the particle diameter at which the integrated value of the number is 90% in the number integrated distribution curve measured by a Coulter counter, like the average dispersed particle diameter.

The resin particles of the present invention have a compression elastic modulus (10% K value) of 6,000 N / mm ² or more and 20,000 N / mm ² or less when the diameter is displaced by 10%. If the 10% K value of the resin particles exceeds 20,000 N / mm ² , the amount of deformation of the particles decreases and the initial resistance value increases, but if it is 20,000 N / mm ² or less, the softness is maintained. Accordingly, it is possible to sufficiently reduce the resistance value at the initial stage of connection and to suppress an increase in resistance value over time after the connection. On the other hand, if the 10% K value of the resin particles is less than 6,000 N / mm ² , the ability to remove the binder at the time of connection decreases, so the resistance value at the initial stage of connection increases and the connection reliability is impaired. 10% K value of the resin particles is preferably 19,000N / mm ² or less, more preferably 18,000N / mm ² or less, more preferably 15,000N / mm ² or less, more preferably 12,000N / mm ² or less, and most preferably not more than 11,000N / mm ^2, preferably 6500N / mm ² or more, more preferably 7000N / mm ² or more, more preferably 8000 N / mm ² or more, more preferably 9,000N / mm ² That's it.

  The 10% K value of the resin particles can be measured by a compression test using a known fine compression tester, for example, a known fine compression tester (for example, “MCT-W500” manufactured by Shimadzu Corporation). In a compression test in which a load is applied at a load speed of 2.2 mN / sec toward the center of the particle at room temperature, the compression load (N) when the particle is deformed until the particle diameter is displaced by 10% The compression displacement (mm) can be measured and obtained based on the following formula.

（ここで、Ｅ：圧縮弾性率（Ｎ／ｍｍ²）、Ｆ：圧縮荷重（Ｎ）、Ｓ：圧縮変位（ｍｍ）、Ｒ：粒子の半径（ｍｍ）である。）

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

  It is important that the resin particles of the present invention have a compression deformation recovery rate of 40% or more. Thereby, resilience is maintained, the resistance value at the initial stage of connection can be made sufficiently low, and an increase in resistance value over time after connection can be efficiently suppressed. The compression deformation recovery rate is preferably 45% or more, more preferably 50% or more. If the compression deformation recovery rate is too high, the electrode gap may open over time. Therefore, the compression deformation recovery rate is preferably 90% or less, more preferably 80% or less, even more preferably 75% or less, and 70%. The following are most preferred.

In the present invention, the compression deformation recovery rate is first constant in, for example, a compression test in which a load is applied in the center direction of particles using a known micro-compression tester (for example, “MCT-W500” manufactured by Shimadzu Corporation). The maximum load when the load is reduced to the minimum load at the same load load speed as the maximum load L1, and then the maximum load when the load is reduced to the minimum load at the same load removal speed as the above load load speed. Is a value calculated based on the following equation, with the amount of displacement between the first load and the minimum load being determined as the recovery displacement amount L2. Specifically, as described in the examples described later, the load load speed (removal load speed) is set to about 0.45 mN / sec, the maximum load is set to about 2.5 mN, and the minimum load is set to about 0.050 mN. be able to.
Compression deformation recovery rate (%) = (L2 / L1) × 100

The resin particles of the present invention have a compressive elastic modulus (30% K value) of 25,000 N / mm ² or less when the diameter is displaced by 30%. It is preferable for increasing the area. More preferably 20000 N / mm ² or less, more preferably 15,000N / mm ² or less, more preferably 13,000N / mm ^2, particularly preferably not more than 10,000 N / mm ^2. Further, in increasing the elimination ability of the binder at the time of connection, the 30% K value is preferably 4,000N / mm ² or more, more preferably 6,000N / mm ² or more, more preferably 7,000N / mm ² or more It is.

  Hereinafter, the components of the resin particles will be described. First, the resin particles may be particles composed only of an organic material such as a vinyl polymer, or an organic material such as a material (a composite material or the like) including a vinyl polymer and a polysiloxane skeleton. The particle | grains comprised with an inorganic composite material may be sufficient. For example, a resin particle composed of a material containing a vinyl polymer has an organic skeleton formed by polymerizing vinyl groups, and is excellent in elastic deformation during pressure connection. On the other hand, resin particles made of a material containing a polysiloxane skeleton are excellent in contact pressure with respect to the connected body during pressure connection. Therefore, resin particles composed of a material in which a polysiloxane skeleton and a vinyl polymer are combined are excellent in elastic deformation and contact pressure, and the connection reliability of the obtained conductive fine particles is further improved.

  As the monomer component constituting the resin particles, a vinyl monomer may be used to form an organic skeleton, and a silane monomer may be used to form a polysiloxane skeleton. Here, vinyl monomers are classified into vinyl crosslinkable monomers and vinyl noncrosslinkable monomers, and silane monomers are silane crosslinkable monomers and silane noncrosslinkable monomers. Divided into masses.

  The vinyl-based crosslinkable monomer has a vinyl group and can form a crosslinked structure, and specifically, a monomer (monomer having two or more vinyl groups in one molecule). (1)), or a monomer having one vinyl group and a functional group other than a vinyl group in one molecule (such as a carboxyl group, a protonic hydrogen-containing group such as a hydroxy group, or a terminal functional group such as an alkoxy group). (Monomer (2)). However, in the case of the monomer (2), in order to form a crosslinked structure as a vinyl-based crosslinkable monomer, the reaction (bonding) of the carboxyl group, hydroxy group, alkoxy group, etc. of the monomer (2) The partner group must be present in the other monomer.

  In the present invention, the “vinyl group” means not only a carbon-carbon double bond but also a polymerizable carbon-like (meth) acryloyl group, allyl group, isopropenyl group, vinylphenyl group, isopropenylphenyl group. A substituent having a carbon double bond is also included. In the present specification, “(meth) acryloyl group”, “(meth) acrylate” and “(meth) acryl” are “acryloyl group and / or methacryloyl group”, “acrylate and / or methacrylate” and “acryl and "/ Or methacryl".

  Examples of the monomer (1) among the vinyl-based crosslinkable monomers include, for example, allyl (meth) acrylates such as allyl (meth) acrylate; ethylene glycol di (meth) acrylate, 1,4-butane Diol 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) ) Alkanediol di (meth) acrylate such as acrylate; diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, decaethylene glycol di (meth) acrylate, pentadecaethylene glycol di (meth) acrylate, penta contactor Ethylene glycol di ( ) Di (meth) acrylates such as polyalkylene glycol di (meth) acrylates such as polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate; trimethylol Tri (meth) acrylates such as propane tri (meth) acrylate; tetra (meth) acrylates such as pentaerythritol tetra (meth) acrylate; hexa (meth) acrylates such as dipentaerythritol hexa (meth) acrylate; divinylbenzene , Divinylnaphthalene, and aromatic hydrocarbon-based crosslinking agents such as derivatives thereof (preferably styrenic polyfunctional monomers such as divinylbenzene); N, N-divinylaniline, divinyl ether , Divinyl sulfide, hetero atom-containing crosslinking agents such as divinyl sulfonic acid; and the like. Among these, in order to obtain the conductive fine particles of the present invention having a 10% K value in a predetermined range, (meth) acrylates (polyfunctional (meth) having two or more (meth) acryloyl groups in one molecule. Acrylate) and styrenic polyfunctional monomers are preferred, and polyfunctional (meth) acrylates are more preferred. Among the polyfunctional (meth) acrylates, acrylates having two or more acryloyl groups in one molecule are preferable, and among them, diacrylates having two acryloyl groups in one molecule are preferable. Among the styrenic polyfunctional monomers, monomers having two vinyl groups in one molecule such as divinylbenzene are preferable. A monomer (1) may be used independently and may use 2 or more types together.

  Examples of the monomer (2) among the vinyl-based crosslinkable monomers include, for example, monomers having a carboxyl group such as (meth) acrylic acid; 2-hydroxyethyl (meth) acrylate, 2- Monomers having hydroxy groups such as hydroxy group-containing (meth) acrylates such as hydroxypropyl (meth) acrylate and 2-hydroxybutyl (meth) acrylate, hydroxy group-containing styrenes such as p-hydroxystyrene; 2-methoxy A single group having an alkoxy group such as an alkoxy group-containing (meth) acrylate such as ethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, or an alkoxystyrene such as p-methoxystyrene. And the like. A monomer (2) may be used independently and may use 2 or more types together.

The vinyl non-crosslinkable monomer is a monomer having one vinyl group in one molecule (monomer (3)) or other than the vinyl group possessed by the monomer (2). The monomer (2) when the other monomer which has a group which reacts with a functional group does not exist in a monomer component is mentioned.
Examples of the monomer (3) among the vinyl non-crosslinkable monomers include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and n-butyl (meth) acrylate. , 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 Alkyl (meth) acrylates such as (meth) acrylate and 2-ethylhexyl (meth) acrylate; cyclopropyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cyclooctyl (meth) acrylate Cycloalkyl (meth) acrylates such as rate, cycloundecyl (meth) acrylate, cyclododecyl (meth) acrylate, isobornyl (meth) acrylate, 4-t-butylcyclohexyl (meth) acrylate; phenyl (meth) acrylate, benzyl Aromatic ring-containing (meth) acrylates such as (meth) acrylate, tolyl (meth) acrylate, phenethyl (meth) acrylate; styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p Styrene monofunctional monomers such as alkyl styrenes such as -t-butyl styrene and ethyl vinyl benzene, and halogen group-containing styrenes such as o-chloro styrene, m-chloro styrene and p-chloro styrene; Among these, it is preferable to use a styrene monofunctional monomer, and styrene is more preferable. A monomer (3) may be used independently and may use 2 or more types together.

  The vinyl polymer preferably includes the vinyl crosslinkable monomer (1) as a constituent component. Among them, the vinyl noncrosslinkable monomer (3) and the vinyl crosslinkable monomer are preferable. The aspect containing (1) is preferable. Specifically, an embodiment containing a monomer having two or more (meth) acryloyl groups in one molecule as a constituent component is preferable, and further, having two or more (meth) acryloyl groups in one molecule. An embodiment including a monomer and a styrene polyfunctional monomer, and an embodiment including a styrene monofunctional monomer and a monomer having two or more (meth) acryloyl groups in one molecule are preferable.

  The polysiloxane skeleton is formed by hydrolyzing a silane monomer and generating a siloxane bond by a condensation reaction. In particular, when a silane crosslinkable monomer is used as a silane monomer, a crosslinked structure is formed. Can do. 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 the silane-based crosslinkable monomer that can form the first form include dimethyldivinylsilane, methyltrivinylsilane, and tetravinylsilane. Examples of the silane crosslinkable monomer that can form the second form include tetrafunctional silane monomers such as tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, and tetrabutoxysilane; methyltrimethoxy Examples thereof include trifunctional silane monomers such as silane, methyltriethoxysilane, ethyltrimethoxysilane, and ethyltriethoxysilane. Examples of silane-based crosslinkable monomers that can form the third form include 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, and 3-methacrylic monomer. Having a (meth) acryloyl group such as loxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-acryloxypropyltriethoxysilane, 3-methacryloxyethoxypropyltrimethoxysilane; vinyltrimethoxysilane, Those having a vinyl group such as vinyltriethoxysilane and p-styryltrimethoxysilane; 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) Those having an epoxy group such as trimethoxysilane; 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.

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.
In particular, the polysiloxane skeleton is preferably a skeleton derived from a polymerizable polysiloxane having a radical-polymerizable carbon-carbon double bond (for example, a vinyl group such as a (meth) acryloyl group). That is, the polysiloxane skeleton has, as a constituent component, a silane-based crosslinkable monomer (preferably having a (meth) acryloyl group, more preferably 3-methacryloxy) capable of forming the crosslinked structure of the third form. A polysiloxane skeleton formed by hydrolysis and condensation of propyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, and vinyltrimethoxysilane) is preferable.

  In addition to the organic materials and organic-inorganic composite materials described above, the resin particles include, for example, polyolefin-based vinyl polymers such as polyethylene, polypropylene, polyvinyl chloride, polytetrafluoroethylene, polyisobutylene, and polybutadiene; polyethylene terephthalate, Polyester such as polyethylene naphthalate; polycarbonate; polyamide; polyimide; phenol formaldehyde resin; melamine formaldehyde resin; melamine benzoguanamine formaldehyde resin; urea formaldehyde resin;

In the present invention, in order to control the 10% K value and the compression deformation recovery rate of the resin particles to be in the above-described ranges, for example, the monomer component constituting the resin particles may include the following specific crosslinkable monomer ( a) and / or the following specific crosslinkable monomer (b) (hereinafter, the specific crosslinkable monomer (a) and the specific crosslinkable monomer (b) are collectively referred to as “specific crosslinkable monomer”). More preferably, the following specific crosslinkable monomer (b) is contained in an amount of 50% by mass or more in a total amount of 100% by mass of the monomer components (specifically, the specific crosslinkable monomer). When both (a) and the specific crosslinkable monomer (b) are contained, the monomer components may be adjusted so that the total content thereof is 50% by mass or more.
Specific crosslinkable monomer (a): having two vinyl groups in one molecule, and having 5 or more atoms linked between carbon-carbon double bonds (C = C) of both vinyl groups A crosslinkable monomer in which a chain unit having a main chain portion is interposed.
Specific cross-linkable monomer (b): one molecule having one vinyl group and a silicon atom to which two condensable groups are bonded, and a carbon-carbon double bond (C = C) and a crosslinkable monomer in which a chain unit having a main chain part in which 5 or more atoms are connected is interposed between a silicon atom (Si).
Here, another branched chain may be bonded to the main chain part in which 5 or more atoms are linked (in other words, no ring is formed). Preferably, the main chain part is a carbon atom and And / or a series of oxygen atoms. In the specific crosslinkable monomer, the number of atoms constituting the main chain portion in a continuous manner is 5 or more, preferably 10 or more, and the upper limit is preferably 30 and more preferably 20. Note that the number of atoms constituting the main chain portion does not count the carbon atom of the carbon-carbon double bond (C = C) itself and the silicon atom itself.

  Vinyl crosslinkable monomers that do not correspond to the specific crosslinkable monomer (a) (for example, styrene polyfunctional monomers such as divinylbenzene), and silane crosslinkable monomers that do not correspond to the specific crosslinkable monomer (b). When it is a monomer (for example, a silane-based crosslinkable monomer having three condensable groups together with one vinyl group), the cross-linked structure formed has rigid benzene or a three-dimensional polysiloxane unit, A network structure having a relatively short distance between the bridging points and a randomly branched high rigidity is obtained. Therefore, the repulsive force of the particles (the above-mentioned compression deformation recovery rate) can be increased in proportion to the added amount, but on the other hand, the hardness is remarkably increased and the softness (10% K described above) is aimed at in the present invention. Value).

  On the other hand, when a predetermined chain unit is interposed between the crosslinking points as in the specific crosslinkable monomer (a) or the specific crosslinkable monomer (b), other than the specific crosslinkable monomer Like a crosslinkable monomer (hereinafter also referred to as “non-specific crosslinkable monomer”), a network structure randomly branched by a vinyl group or a condensable group is formed, which increases the repulsive force of particles. Although the softness is impaired (hardness increases), the distance between the cross-linking points becomes a certain length or more, so that the network structure becomes more dense as the non-specific cross-linking monomer is used. As a result, it becomes easy to suppress an increase in hardness.

  Furthermore, in the case of a silane-based crosslinkable monomer having one vinyl group and two condensable groups as in the specific crosslinkable monomer (b), the vinyl group site and the condensable group site are respectively Since crosslinking proceeds selectively and a linear main chain is formed at each site, a regular ladder-shaped crosslinking structure is formed. With such a regular ladder-like bridge structure, it is possible to express a high repulsive force while more reliably suppressing an increase in hardness. In particular, when cross-linking is performed sequentially (for example, at the time of particle preparation, a first main chain is first formed by one of a siloxane bond and a vinyl bond, and then a second is formed by the other of the siloxane bond and the vinyl bond. ), A more strict regular structure is easily formed, and the above-described compression deformation recovery rate can be further increased. When the specific crosslinkable monomer (b) is used in this way, resin particles in a suitable range are easily obtained not only at the recovery rate but also at 30% K value or 10% K value.

As the specific crosslinkable monomer (a), di (meth) acrylates exemplified as the monomer (1) among the vinyl-based crosslinkable monomers described above are preferable, and among them, alkanediol di ( (Meth) acrylate (for example, 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, etc.) and polyalkylene glycol di (meth) acrylate (for example, diethylene glycol di (meth) acrylate, triethylene glycol di (meth)) Acrylate, decaethylene glycol di (meth) acrylate, Tadeca ethylene glycol di (meth) acrylate, pentacontactor ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, etc.) are preferred In particular, alkanediol di (meth) acrylate is preferred.
As the specific crosslinkable monomer (b), 3-methacryloxypropylmethyldimethoxy exemplified as the silane crosslinkable monomer capable of forming the third form among the silane crosslinkable monomers described above. Preferable examples include 3-methacryloxypropylalkyldialkoxysilane such as silane and 3-methacryloxypropylmethyldiethoxysilane.

  In order to control the 10% K value and compression deformation recovery rate of the resin particles to the above-described ranges, the total content of the specific crosslinkable monomers (a) and / or (b) constitutes the resin particles. The content may be 50% by mass or more with respect to the total amount (100% by mass) of the monomer components to be processed, but is preferably 60% by mass or more, more preferably 70% by mass or more, and further preferably 75% by mass or more. However, if the total amount of the specific crosslinkable monomers (a) and / or (b) is too large, the ratio of the other crosslinkable monomers may be reduced and the 10% K value may be too small. Therefore, the total amount of the specific crosslinkable monomers (a) and / or (b) is preferably 95% by mass or less with respect to the total amount (100% by mass) of the monomer components constituting the resin particles. Preferably it is 90 mass% or less, More preferably, it is 85 mass% or less.

Furthermore, in order to reliably control the 10% K value and the compression deformation recovery rate of the resin particles in the above-described range, the monomer component constituting the resin particles is selected as described above, and the resin particles are selected. It is preferable to perform firing (heat treatment). In particular, when the specific crosslinkable monomer (b), which is a silane-based crosslinking monomer, is used as the monomer component, the compression deformation recovery rate is further increased by firing the obtained resin particles. It becomes possible.
Conditions for firing may be set as appropriate. For example, the firing temperature is preferably 200 ° C or higher, more preferably 250 ° C or higher, further preferably 280 ° C or higher, preferably 500 ° C or lower, and 450 ° C or lower. More preferred is 400 ° C. or lower. The heating atmosphere during firing is preferably an inert gas atmosphere such as nitrogen.
The shape of the resin particles (base material) is not particularly limited, and may be any of a spherical shape, a spheroid shape, a confetti shape, a thin plate shape, a needle shape, an eyebrow shape, etc., and a spherical shape is preferable. A true spherical shape is particularly preferable.

2. Conductive fine particles In the conductive fine particles of the present invention, at least one conductive metal layer is formed on the surface of the substrate (resin particles). 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-phosphorous, 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. Further, in terms of inexpensiveness, nickel, nickel alloy (Ni-Au, Ni-Pd, Ni-Pd-Au, Ni-Ag, Ni-P, Ni-B, Ni-Zn, Ni-Sn, Ni-W, Ni—Co, Ni—W, Ni—Ti); copper, copper alloy (Cu and Fe, Co, Ni, Zn, Sn, In, Ga, Tl, Zr, W, Mo, Rh, Ru, Ir, Ag, Alloy with at least one metal element selected from the group consisting of Au, Bi, Al, Mn, Mg, P, B, preferably an alloy with Ag, Ni, Sn, Zn); Silver, silver alloy (Ag And Fe, Co, Ni, Zn, Sn, In, Ga, Tl, Zr, W, Mo, Rh, Ru, Ir, Ag, Au, Bi, Al, Mn, Mg, P, B An alloy with at least one metal element, preferably Ag-Ni, Ag-Sn, A -Zn); tin, tin alloy (for example, Sn-Ag, Sn-Cu, Sn-Cu-Ag, Sn-Zn, Sn-Sb, Sn-Bi-Ag, Sn-Bi-In, Sn-Au, Sn- Pb and the like) are preferable. Of these, nickel and nickel alloys are preferred. The conductive metal layer may be a single layer or multiple layers. In the case of multiple layers, for example, a combination of nickel-gold, nickel-palladium, nickel-palladium-gold, nickel-silver, etc. Is preferred.

The thickness of the conductive metal layer is preferably 0.010 μm or more, more preferably 0.030 μm or more, further preferably 0.050 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 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 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, still more preferably 2.3 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 was based on the number average particle size of 3000 particles. Is preferably adopted.

The conductive fine particles of the present invention preferably have a compressive modulus (10% K value of the conductive fine particles) of 30,000 N / mm ² or less, more preferably 25,000 N when the diameter is displaced by 10%. / mm ² or less, more preferably 20000 N / mm ² or less, more preferably 18,000N / mm ^2, and most preferably not more than 15,000N / mm ^2. Further, the 10% K value of the conductive fine particles is preferably 6,000 N / mm ² or more, more preferably 7,000 N / mm ² or more, and further preferably 8,000 N / mm ² or more. If the 10% K value of the conductive fine particles is within this range, the particles will retain a certain degree of softness, the resistance value at the initial stage of connection can be sufficiently lowered, and the resistance value with time after connection can be increased. It becomes possible to suppress. 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 preferably have a compression deformation recovery rate of 40% or more, more preferably 45% or more, and more preferably 50% or more. As a result, the particles retain resilience, the resistance value at the initial stage of connection can be made sufficiently low, and the increase in resistance value over time after connection can be efficiently suppressed. Moreover, since the compression deformation recovery rate of the conductive fine particles is too high, the electrode gap may open over time, so 90% or less is preferable, 80% or less is more preferable, 75% or less is more preferable, and 70% or less. Is most preferred. The compression deformation recovery rate of the conductive fine particles can be measured in the same manner as the compression deformation recovery rate of the resin particles.

The conductive fine particles of the present invention may 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 to 1 μm, more preferably 0.02 μm to 0.5 μm, still more preferably 0.03 μm to 0.4 μm. 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.

3. Manufacturing method First, the manufacturing method of the said resin particle used as a base material is demonstrated.
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 method, and the like. For example, a method in which resin particles are synthesized by seed polymerization and then classified 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 is a method of obtaining resin particles through a seed particle preparation step, an absorption step in which the seed particle absorbs the monomer component, and a polymerization step in which the monomer component absorbed in the seed particle is polymerized. The method and conditions in each step are not particularly limited as long as a known seed polymerization method is appropriately employed. For example, the following methods are preferably employed.
In the seed particle preparation step, when synthesizing resin particles composed only of an organic material, the seed particles are prepared by a method such as soap-free emulsion polymerization or dispersion polymerization using the vinyl monomer. Good. In this case, it is preferable to use a styrene monofunctional monomer such as styrene as the vinyl monomer. On the other hand, when synthesizing particles composed of an organic material and a material having a polysiloxane skeleton, a solvent containing water (for example, alcohols, ketones, esters, ( The seed particles (polysiloxane particles) may be prepared by hydrolysis and condensation polymerization in a mixed solvent of an organic solvent such as cyclo) paraffins and aromatic hydrocarbons and water. In this case, it is preferable to use a silane crosslinkable monomer having a radical polymerizable group as the silane monomer to form polymerizable polysiloxane particles. In the hydrolysis and polycondensation, basic catalysts such as ammonia, urea, ethanolamine, tetramethylammonium hydroxide, alkali metal hydroxide, and alkaline earth metal hydroxide can be preferably used as the catalyst. If necessary, an anionic, cationic or nonionic surfactant or a polymer dispersant such as polyvinyl alcohol or polyvinylpyrrolidone can be used in combination.

  The method for absorbing the monomer component in the seed particles in the absorption step is not particularly limited. For example, the monomer component may be added to a seed particle dispersion in which the seed particles are previously dispersed in a solvent. The seed particles may be added to the solvent containing the monomer component. In particular, in the former method, the reaction solution obtained by polymerization, hydrolysis, or condensation may be used as a seed particle dispersion as it is. From the viewpoint of simplification and productivity. The monomer component may be added alone, or may be added as a solution dissolved in a solvent, but in order to efficiently absorb the seed particles, water or an aqueous medium ( For example, it is preferable to add as an emulsified liquid by emulsifying and dispersing in a water-soluble organic solvent such as alcohols, ketones and esters, or a mixed solvent of these with water).

When emulsifying and dispersing the monomer component with an emulsifier, examples of the emulsifier include anionic surfactants, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters. , Dispersion state of seed particles after nonionic surfactant such as polyoxysorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin fatty acid ester, oxyethylene-oxypropylene block polymer absorbs monomer component Is preferably used in that it can be stabilized. In addition, the amount of water or aqueous medium used for emulsification and dispersion is usually 0.3 to 10 times the mass of the monomer component.
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.

  The polymerization method employed in the polymerization step is not particularly limited, and for example, a known method such as a method using a radical polymerization initiator (for example, a peroxide-based initiator, an azo-based initiator, etc.) can be used. The reaction temperature at the time of performing 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 tends to occur during the polymerization. There is. 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. If the reaction time is too short, the degree of polymerization may not be sufficiently increased, and if the reaction time is too long, aggregation tends to occur between particles. In such a polymerization step, when the seed particles are polymerizable polysiloxane particles, in the polymerization step, the absorbed monomer component and the radical polymerizable group of the polymerizable polysiloxane skeleton are polymerized, A polysiloxane skeleton and a vinyl polymer are combined.

  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. 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.

After the synthesis, the resin particles classified as necessary are usually dried and optionally subjected to firing. In particular, when a silane cross-linking monomer (or a specific cross-linking monomer (b)) is used as the monomer component, it is recommended to apply the resin particles after polymerization as described above. The heating conditions for drying and firing may be set as appropriate within the above range, and are not particularly limited.
As described above, the resin particles have an average particle diameter (number-based average dispersed particle diameter) in the range of 1.0 μm or more and 2.5 μm or less, preferably in the range of the preferable average particle diameter as the base material particle described above. Prepared to satisfy.

Next, conductive fine particles are obtained by forming a conductive metal layer on the resin particles (base material) obtained as described above and further forming an insulating resin layer as necessary.
The formation method of the conductive metal layer and the formation method of the insulating resin layer are not particularly limited. For example, the conductive metal layer is plated on the substrate surface by an electroless plating method, an electrolytic plating method, or the like; Or a method of forming a conductive metal layer by a physical vapor deposition method such as vacuum vapor deposition, ion plating, or ion sputtering; 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.

4). 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. For example, 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 particle diameter and coefficient of variation (CV value) of seed particles and resin particles>
In the case of resin particles, 1% 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. A dispersion obtained by adding 20 parts of an aqueous solution and ultrasonically dispersing for 10 minutes is used as a measurement sample. In the case of seed particles, a dispersion obtained by hydrolysis and condensation reaction is added to a polyoxyethylene alkyl ether sulfate ammonium salt ( Using a sample diluted with a 1% aqueous solution of “Hitenol (registered trademark) N-08” manufactured by Daiichi Kogyo Seiyaku Co., Ltd. as a measurement sample, using a particle size distribution analyzer (“Coulter Multisizer Type III” manufactured by Beckman Coulter, Inc.) The particle diameter (μm) of 30000 particles was measured, and the number-based average dispersed particle diameter was determined. For the resin particles, the standard deviation of the particle diameter on the basis of the number is obtained together with the average dispersed particle diameter, and the coefficient of variation (CV value) of the particle diameter is calculated according to the following formula.
Particle variation coefficient (%) = 100 × (standard deviation of particle diameter / average dispersed 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. The measurement was performed by adding 17.5 parts of a 1.4% aqueous solution of polyoxyethylene oleyl ether (“Emulgen (registered trademark) 430” manufactured by Kao Corporation) as an emulsifier to 0.05 parts of the particles, After dispersing for 10 minutes. And the film thickness of the electroconductive metal layer was computed according to the following formula.
Conductive metal layer thickness (μm) = (Y−X) / 2

<10% K value and 30% K value 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 stage (material: SKS flat plate) at room temperature (25 ° C.). Using (material: diamond), a load was applied at a constant load speed (2.2 mN / sec) toward the center of the particles in the “standard surface detection” mode. The load value (mN) when the compression displacement becomes 10% of the particle diameter, the displacement amount (μm) at that time, the load (mN) when the compression displacement becomes 30% of the particle diameter, and The amount of displacement (μm) was measured. In addition, the measurement was performed on 10 different particles for each sample, and the average value was used as the measurement value. Then, the obtained load value (mN) is converted into a compressive load (N), the obtained displacement amount (μm) is converted into a compressive displacement (mm), and the average particle diameter (μm) of the resin particles is used to calculate the particle size. The radius (mm) was calculated and calculated based on the following formula using these.

（ここで、Ｅ：圧縮弾性率（Ｎ／ｍｍ²）、Ｆ：圧縮荷重（Ｎ）、Ｓ：圧縮変位（ｍｍ）、Ｒ：粒子の半径（ｍｍ）である。）

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

<Compression deformation recovery 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 stage (material: SKS flat plate) at room temperature (25 ° C.). Using (material: diamond), in the “soft surface detection” mode, compress to the maximum load (2.452 mN) at a constant load speed (0.4462 mN / sec) toward the center of the particle, and the amount of displacement ( μm) was measured and this was taken as the maximum displacement L1. Next, the displacement (μm) between the maximum load and the minimum load when the load is reduced to the minimum load (0.049 mN) at a constant unloading speed (0.4462 mN / sec) is measured. Was the recovery displacement L2. In addition, the measurement was performed on 10 different particles for each sample, and the average value was used as the measurement value.
Compression deformation recovery rate (%) = (L2 / L1) × 100

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, 1700 parts of ion-exchanged water, 24 parts of 25% aqueous ammonia and 700 parts of methanol are placed under stirring and the monomer component (( 40 parts of 3-methacryloxypropyltrimethoxysilane is added as a seed-forming monomer), and hydrolysis and condensation reaction of 3-methacryloxypropyltrimethoxysilane is performed to obtain polymerizable polysiloxane particles having methacryloyl groups (seed particles) An average dispersion particle size based on the number of the polysiloxane particles was 1.20 μm.

  Next, 4.0 parts of 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 160 parts of ion-exchanged water. In the solution, 160 parts of 3-methacryloxypropylmethyldimethoxysilane as a monomer component (absorbing monomer) and 2,2′-azobis (2,4-dimethylvaleronitrile) (“W- 65 ") 2.0 parts dissolved solution was added and emulsified and dispersed to prepare an emulsion of monomer component (absorbing monomer). Two hours after the start of emulsification dispersion, the obtained emulsion was added to a dispersion 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, 9.6 parts of a 20% aqueous solution of polyoxyethylene styrenated phenyl ether sulfate ammonium salt was added, the reaction solution was heated to 65 ° C. under a nitrogen atmosphere, and kept at 65 ° C. for 2 hours. The components were radically polymerized. The emulsion after radical polymerization was subjected to solid-liquid separation, and the resulting cake was washed with ion-exchanged water and methanol, then vacuum-dried at 120 ° C. for 2 hours in a nitrogen atmosphere, and further dried to obtain resin particles. Heat treatment (baking) was performed at 300 ° C. for 1 hour in a nitrogen atmosphere to obtain resin particles (1). The average particle diameter, CV value, 10% K value, 30% K value, and compression deformation recovery rate of the obtained resin particles were as shown in Table 1.

(Production Example 2)
In preparing a dispersion of polysiloxane particles (seed particles), the amount of ion-exchanged water used is 1800 parts, the amount of methanol used is 600 parts, and the type and amount of absorbing monomer are 3-methacryloxypropylmethyldimethoxy. While changing to 168 parts of silane and 32 parts of 1,6-hexanediol diacrylate, drying was performed by vacuum drying at 120 ° C. for 2 hours in a nitrogen atmosphere, and the resin particles obtained by drying were further subjected to a nitrogen atmosphere. Resin particles (2) were obtained in the same manner as in Production Example 1 except that heat treatment (baking) was performed at 230 ° C. for 1 hour. The average particle diameter, CV value, 10% K value, 30% K value, and compression deformation recovery rate of the obtained resin particles were as shown in Table 1.

(Production Example 3)
Resin particles (3) were obtained in the same manner as in Production Example 1 except that the heat treatment (firing) was not performed. The average particle diameter, CV value, 10% K value, 30% K value, and compression deformation recovery rate of the obtained resin particles were as shown in Table 1.

(Production Example 4)
The type and amount of the absorbing monomer were 100 parts 3-methacryloxypropylmethyldimethoxysilane, 50 parts 1,6-hexanediol diacrylate, and divinylbenzene (“DVB960” manufactured by Nippon Steel Chemical Co., Ltd .: 96% divinylbenzene, vinyl Resin particles (4) were obtained in the same manner as in Production Example 2, except that the content was changed to 50 parts) (non-crosslinkable monomer (containing 4% ethyl vinylbenzene)). The average particle diameter, CV value, 10% K value, 30% K value, and compression deformation recovery rate of the obtained resin particles were as shown in Table 1.

(Production Example 5)
In preparing a dispersion of polysiloxane particles (seed particles), the amount of ion exchange water used is changed to 1800 parts, the amount of methanol used is changed to 600 parts, and the type and amount of absorbing monomer are changed to 240 parts of styrene. Resin particles (5) were obtained in the same manner as in Production Example 1 except that drying was performed by vacuum drying at 80 ° C. for 12 hours in a nitrogen atmosphere, and no baking was performed after drying. The average particle diameter, CV value, 10% K value, 30% K value, and compression deformation recovery rate of the obtained resin particles were as shown in Table 1.

(Production Example 6)
In preparing a dispersion of polysiloxane particles (seed particles), the amount of ion-exchanged water used is 1600 parts, the amount of methanol used is 800 parts, the type and amount of absorbing monomer is 40 parts of styrene, and 1, Except for changing to 6 parts of 6-hexanediol diacrylate and drying by vacuum drying at 120 ° C. for 2 hours in a nitrogen atmosphere and not firing after drying, the same as in Production Example 1, Resin particles (6) were obtained. The average particle diameter, CV value, 10% K value, 30% K value, and compression deformation recovery rate of the obtained resin particles were as shown in Table 1.

(Production Example 7)
The type and amount used of the absorbing monomer were changed to 97 parts of styrene and 23 parts of 1,6-hexanediol dimethacrylate, and the drying was performed by vacuum drying at 120 ° C. for 2 hours in a nitrogen atmosphere, and firing was performed after drying. Resin particles (7) were obtained in the same manner as in Production Example 2, except that the application was not performed. The average particle diameter, CV value, 10% K value, 30% K value, and compression deformation recovery rate of the obtained resin particles were as shown in Table 1.

(Production Example 8)
Change the type and amount of absorption monomer to 200 parts divinylbenzene (“DVB960” manufactured by Nippon Steel Chemical Co., Ltd .: 96% divinylbenzene, 4% vinyl non-crosslinkable monomer (ethyl vinylbenzene etc.)) In addition, drying is performed by vacuum drying at 120 ° C. for 2 hours in a nitrogen atmosphere, and the resin particles obtained by drying are further manufactured by heating (baking) at 280 ° C. for 1 hour in a nitrogen atmosphere. Resin particles (8) were obtained in the same manner as in Example 1. The average particle diameter, CV value, 10% K value, 30% K value, and compression deformation recovery rate of the obtained resin particles were as shown in Table 1.

(Production Example 9)
In a four-necked flask equipped with a condenser, a thermometer, and a dropping port, 200 parts of ion-exchanged water, 685 parts of ethanol, 12 parts of polyvinylpyrrolidone (“PVP K-30” manufactured by Wako Pure Chemical Industries, Ltd.), azobisiso Radical polymerization of monomer components by adding 2.1 parts of butyronitrile (AIBN) and 100 parts of styrene, stirring, raising the temperature to 70 ° C. under a nitrogen atmosphere, and holding at 70 ° C. for 6 hours Then, the mixture was cooled to room temperature to prepare a suspension of polystyrene particles (seed particles). The number-based average dispersed particle size of the polystyrene particles was 1.29 μm.

  Next, a solution obtained by diluting 25 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 with 500 parts of ion-exchanged water. In addition, 500 parts of 1,9-nonanediol dimethacrylate as a monomer component (absorbing monomer) and 2,2′-azobis (2,4-dimethylvaleronitrile) (“V-65” manufactured by Wako Pure Chemical Industries, Ltd.) ) A solution in which 6 parts were dissolved was added and emulsified and dispersed to prepare an emulsion of monomer components (absorbing monomers). The obtained emulsion was added to the suspension of polystyrene particles (seed particles) and further stirred. Three hours after the addition of the emulsified liquid, the obtained mixed liquid was sampled and observed with a microscope. As a result, it was confirmed that the polystyrene particles absorbed the absorbing monomer and became enlarged.

  Next, 120 parts of a 10% aqueous solution of polyvinyl alcohol (“Poval (registered trademark) 205” manufactured by Kuraray Co., Ltd.) and 500 parts of ion-exchanged water are added to the mixture, and the temperature is raised to 65 ° C. in a nitrogen atmosphere. Was held for 2 hours to carry out radical polymerization of the monomer component. The reaction solution (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 80 ° C. for 4 hours in a nitrogen atmosphere to obtain resin particles (9). Obtained. The average particle diameter, CV value, 10% K value, 30% K value, and compression deformation recovery rate of the obtained resin particles were as shown in Table 1.

(Production Example 10)
In a solution obtained by dissolving 10 parts of a 20% aqueous solution of polyoxyethylene styrenated phenyl ether sulfate ammonium salt ("Hytenol (registered trademark) NF-08" manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an emulsifier in 300 parts of ion-exchanged water, As monomer components, 80 parts of 1,6-hexanediol diacrylate and 20 parts of methyl methacrylate, 2,2′-azobis (2,4-dimethylvaleronitrile) (“V-65” manufactured by Wako Pure Chemical Industries, Ltd.) ) 2.0 parts of a dissolved solution was added and emulsified and dispersed to prepare an emulsion of monomer components. The obtained emulsified liquid was 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, heated to 65 ° C. under a nitrogen atmosphere, and heated to 65 ° C. Was held for 2 hours to carry out radical polymerization of the monomer component. The reaction solution (emulsion) after radical polymerization was separated into solid and liquid, and the resulting cake was washed with ion-exchanged water and methanol, then subjected to wet classification, and dried in vacuo at 120 ° C. for 2 hours to obtain resin particles ( 10) was obtained. The average particle diameter, CV value, 10% K value, 30% K value, and compression deformation recovery rate of the obtained resin particles were as shown in Table 1.

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 1.

(Examples 2-6, Comparative Examples 1-4)
Conductive fine particles were produced in the same manner as in Example 1 except that the resin particles shown in Table 1 were used as the substrate. The film thickness of the conductive metal layer in the obtained conductive fine particles was as shown in Table 1.

3. Preparation and Evaluation of Anisotropic Conductive Material Using conductive fine particles obtained in Examples and Comparative Examples, an anisotropic conductive material (anisotropic conductive film) was prepared by the following method, and the performance was evaluated by the following method. It was evaluated with.
That is, 1 part of conductive fine particles, 100 parts of an epoxy resin (Mitsubishi Chemical "JER828") as a binder resin, 2 parts of a curing agent ("San-Aid (registered trademark) SI-150" manufactured by Sanshin Chemical Co., Ltd.), 100 parts of toluene was added, 50 parts of φ1 mm zirconia beads 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 at a pitch of 20 μm, under pressure bonding conditions of 1 MPa and 190 ° C. Thermocompression bonding was performed. Then, the initial resistance value A between the electrodes is measured. When the initial resistance value A is 3Ω or less, the connection resistance is “◎”, when it exceeds 3Ω and less than 5Ω, the connection resistance is “◯” and exceeds 5Ω. The connection resistance was evaluated as “×”.
Further, after the obtained anisotropic conductive film 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 calculated based on the following formula: “Excellent” when the rate of increase (%) is 0.5% or less, “Good” when it exceeds 0.5% and 1% or less, “Yes” when it exceeds 1% and 3% or less, 3% The case of exceeding was evaluated as “impossible”.
Resistance value increase rate (%) = [(B−A) / A] × 100

  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 (6)

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 resin particles have an average particle size of 1.0 μm to 2.5 μm,
The compression elastic modulus (10% K value) when the diameter of the resin particles is displaced by 10% is 6,000 N / mm ² or more and 20,000 N / mm ² or less,
Conductive fine particles, wherein the resin particles have a compression deformation recovery rate of 40% or more. ^2. 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 25,000 N / mm ² or less. The conductive fine particles according to claim 1 or 2, wherein a compression elastic modulus (30% K value) when the diameter of the resin particles is displaced by 30% is 15,000 N / mm ² or less.   The conductive fine particles according to any one of claims 1 to 3, wherein a compression deformation recovery rate of the resin particles is 50% or more. The monomer component constituting the resin particles is at least one of the following specific crosslinkable monomer (a) and the following specific crosslinkable monomer (b), and is 50% by mass in 100% by mass of the total monomer component. The electroconductive fine particle of any one of Claims 1-4 contained above.
Specific crosslinkable monomer (a): having two vinyl groups in one molecule, and having 5 or more atoms linked between carbon-carbon double bonds (C = C) of both vinyl groups A crosslinkable monomer in which a chain unit having a main chain portion is interposed.
Specific cross-linkable monomer (b): one molecule having one vinyl group and a silicon atom to which two condensable groups are bonded, and a carbon-carbon double bond (C = C) and a crosslinkable monomer in which a chain unit having a main chain part in which 5 or more atoms are connected is interposed between a silicon atom (Si).   An anisotropic conductive material comprising the conductive fine particles according to claim 1 dispersed in a binder resin.