JP6719859B2 - Polymer fine particles, conductive fine particles and anisotropic conductive materials - Google Patents

Description

The present invention relates to polymer fine particles, conductive fine particles having a conductive metal layer formed on the surface of the polymer fine particles, and an anisotropic conductive material containing the conductive fine particles.

2. Description of the Related Art Conventionally, in assembling electronic equipment, a connection method using an anisotropic conductive material has been adopted to electrically connect a large number of opposing electrodes and wirings. The anisotropic conductive material is a material in which conductive fine particles are dispersed in a binder resin or the like, and is, for example, an anisotropic conductive paste (ACP), an anisotropic conductive film (ACF), an anisotropic conductive ink, or an anisotropic conductive material. There are sheets, etc. As the conductive fine particles used in this anisotropic conductive material, in addition to metal particles, resin particles serving as a base material whose surface is coated with a conductive metal layer are used. The conductive fine particles composed of resin particles and a conductive metal layer have an electrically connected metal layer formed on the surface for electrical connection between electrodes and wirings.

Conventionally, attempts have been made to increase the connection area by increasing the particle size of the conductive fine particles (for example, the number average particle size is 5 μm or more) to reduce the initial resistance and increase the connection reliability. In Patent Document 1, the conductive fine particles having a nickel coating layer and a gold layer formed on the fine spheres having an average particle diameter of 6 μm are more conductive than the conductive fine particles having the nickel coating layer and the gold layer formed on the fine spheres having an average particle diameter of 0.1 μm. It is shown that the fine particles did not cause poor connection and had a lower connection resistance value.

Japanese Patent No. 3782590

However, although the conductive fine particles described in Patent Document 1 can reduce the initial resistance value, there are cases in which an increase in the connection resistance value when held for a long time under high temperature and high humidity conditions cannot be sufficiently suppressed.

The present invention has been made in view of the above circumstances, and it is possible to lower the initial resistance value, and conductive fine particles in which an increase in connection resistance value is suppressed even when held for a long time under high temperature and high humidity conditions. An object of the present invention is to provide an anisotropic conductive material using the same, and polymer fine particles used therein.

As a result of intensive studies to solve the above problems, the present inventors have increased the hardness at the initial stage of compression as a base material of conductive fine particles while keeping the coefficient of variation of the particle diameter below a certain level. By using polymer particles, it is possible to form indentations on the electrode, and as a result, the initial resistance can be made lower than in the case of simply increasing the particle size, and the connection resistance value even after holding for a long time under hot and humid conditions. The present invention has been completed by finding that the rise can be suppressed.

That is, the polymer fine particles according to the present invention have a number average particle diameter of 5 μm or more and 15 μm or less, a number-based particle diameter variation coefficient (CV value) of 10% or less, and a Si content of 12 mass. % Or more and 35% by mass or less, and the 10% K value is 4500 (N/mm ² ) or more when the compression elastic modulus when the diameter of the polymer fine particles is displaced by 10% is 10% K value. Is characterized by.

Further, the technical scope of the present invention includes the following general formula (s-1)

[In the general formula (s-1), R ¹ represents a hydrogen atom or a methyl group, and R ² represents a single bond or a divalent aromatic hydrocarbon group. * Represents a bond with a silicon atom. ]
A silane monomer (s1) having at least one polymerizable group bonded to a silicon atom, and the following general formula (s-2)

[In general formula (s-2), R< ¹ > is synonymous with the above. R ³ represents a linear or branched divalent aliphatic hydrocarbon group. * Represents a bond with a silicon atom. ]
Polymer particles obtained by polymerizing a seed monomer obtained from a silane monomer (s2) having at least one polymerizable group represented by the formula Also included are seed polymer particles having a size of 5 μm or more and 15 μm or less.

The polymer particles of the present invention are obtained by polymerizing a monomer composition in which the mass ratio of vinyl monomer and silane monomer (vinyl monomer/silane monomer) is 0.1 or more and 0.8 or less. It is preferably obtained by

The conductive fine particles having a conductive metal layer on the surface of these polymer fine particles and the anisotropic conductive material containing the conductive fine particles are also included in the technical scope of the present invention.

The polymer fine particles of the present invention have a number average particle diameter of 5 μm or more and 15 μm or less, and the compression modulus at 10% compression while keeping the coefficient of variation (CV value) of the number-based particle diameter at 10% or less. Therefore, the conductive fine particles and anisotropic conductive material using this have low initial resistance, and the increase in connection resistance is suppressed even after holding for a long time under high temperature and high humidity conditions. Become.

(Polymer fine particles)
The polymer fine particles of the present invention have a number average particle diameter of 5 μm or more and 15 μm or less, and the diameter of the polymer fine particles is 10% with the coefficient of variation (CV value) of the number-based particle diameter kept at 10% or less. The 10% K value, which is the compressive elastic modulus when displaced, was set to 4500 (N/mm ² ) or more.

By increasing the hardness at 10% compression of polymer particles having a number average particle size of 5 μm or more and 15 μm or less, indentations are formed on the electrodes to be connected while maintaining the contact area, and the connection resistance value is suppressed. can do. In this case, by maintaining the number-based coefficient of variation (CV value) at 10% or less, indentations can be formed uniformly over the entire electrode.

Here, the 10% K value means the compressive elastic modulus when the diameter of the polymer particles is displaced by 10%, and the 10% compression load when the particles are deformed until the diameter of the particles is displaced by 10%. It can be calculated from (N) and 10% compression displacement amount (mm) based on the following formula.

(In the formula, E is a compression elastic modulus (N/mm ² ), F is a compression load (N), S is a compression displacement amount (mm), and R is a radius (mm) of a sample particle)

In addition, in the present specification, the 10% compression load and the 10% compression displacement amount mean that a load is applied at a constant load speed (2.2786 N/sec) toward the center of the particle at room temperature (25° C.) to perform compression. It means the load value and the displacement amount when the displacement becomes 10% of the particle diameter.

10% K value of the polymer fine particles of the present invention is 4500N / mm ² or more, preferably 5000N / mm ² or more, more preferably 5500N / mm ² or more, more preferably 5800N / mm ² or more There is preferably at 15000 N / mm ² or less, more preferably 12000N / mm ^2, more preferably not more than 10000 N / mm ^2.

Similar to the 10% K value, the 20% K value, 30% K value, and 40% K value can be calculated based on the corresponding compression load and compression displacement amount. 20% K value of the polymer fine particles of the present invention is preferably 4000 N / mm ² or more, more preferably 4500N / mm ² or more, more preferably 5000N / mm ² or more, is 15000 N / mm ² or less It is preferably 12,000 N/mm ² or less, more preferably 10000 N/mm ² or less.

30% K value of the polymer fine particles of the present invention is preferably 4500N / mm ² or more, more preferably 5000N / mm ² or more, more preferably 5200N / mm ² or more, is 15000 N / mm ² or less It is preferably 12,000 N/mm ² or less, more preferably 10000 N/mm ² or less.

Moreover, 40% K value of the polymer fine particles of the present invention is preferably 5000N / mm ² or more, more preferably 5500N / mm ² or more, more preferably 6000 N / mm ² or more, 20000N / mm ² or less it is preferably, more preferably 15000 N / mm ^2, more preferably not more than 12000N / mm ^2.

The number average particle diameter of the polymer fine particles of the present invention is 5.0 μm or more, preferably 5.5 μm or more, more preferably 6.0 μm or more, still more preferably 6.4 μm or more. Further, it is 15.0 μm or less, preferably 13.0 μm or less, more preferably 12.0 μm or less, and further preferably 11.0 μm or less.
Here, the “average particle diameter” in the present invention refers to a number average particle diameter, and a precision particle size distribution measuring apparatus using the Coulter principle (for example, trade name “Coulter Multisizer III type”, Beckman Coulter Inc. Value).

The coefficient of variation in the particle size of the polymer particles of the present invention is 10% or less, preferably 9.0% or less, more preferably 8.0% or less. By suppressing the coefficient of variation of the particle diameter, it is possible to form uniform indentations. Here, the coefficient of variation of the particle diameter in the present invention means the number average particle diameter of the polymer particles measured by a precision particle size distribution measuring apparatus using the Coulter principle and the standard deviation of the particle diameter of the polymer particles as follows. It is a value that can be found by applying it to the formula.
Coefficient of variation of polymer particles (%)=100×standard deviation of particle diameter/number average particle diameter

Further, in the polymer particles of the present invention, the content of the particles remaining on the sieve when passed through a sieve having an opening of 20 μm is preferably 2% by mass or less, more preferably 1% by mass or less, and further preferably 0%. The amount is 0.5% by mass or less, particularly preferably 0.01% by mass or less.

The shape of the polymer fine particles is not particularly limited, and may be, for example, spherical, spheroidal, spinach-like, thin plate-like, needle-like, eyebrows-like, etc. Is preferred.
Further, in the polymer fine particles of the present invention, generation of continuous spherical particles in which a plurality of polymer particles are bonded, aggregated particles in which a plurality of polymer particles are aggregated, and the like are suppressed. In the polymer particles of the present invention, the total content of continuous spherical particles and agglomerated particles is preferably 2% or less on a number basis, more preferably 1% or less, further preferably 0.5% or less, It is particularly preferably 0.01% or less. The number ratio of continuous spherical particles and agglomerated particles can be confirmed using a scanning electron microscope (SEM).

The thermal decomposition initiation temperature of the polymer fine particles of the present invention is preferably 200° C. or higher, more preferably 260° C. or higher, further preferably 280° C. or higher, and usually 500° C. or lower, and It is preferably 450°C or lower, and more preferably 400°C or lower. The thermal decomposition start temperature of the polymer fine particles can be measured by performing thermogravimetric analysis under a nitrogen atmosphere.

Further, the polymer fine particles of the invention preferably include a polysiloxane skeleton, a vinyl polymer skeleton and a polysiloxane skeleton. The polysiloxane skeleton means a skeleton composed of a siloxane bond (Si-O-Si bond), and can increase the contact pressure with respect to the connected body during pressure connection. The vinyl polymer skeleton means a skeleton formed by polymerizing vinyl groups, and is excellent in elastic deformation during pressure connection. The polymer fine particles of the present invention include both the polysiloxane skeleton and the vinyl polymer skeleton, whereby it becomes possible to achieve both hardness and deformability.

At this time, the content of Si present in the polymer fine particles is 12% by mass or more, preferably 16% by mass or more, more preferably 18% by mass or more, and 35% by mass or less, preferably 32% by mass. It is not more than mass%, more preferably not more than 27 mass%. When the Si content is in this range, the above hardness characteristics can be more easily achieved.

The polymer fine particles of the present invention can be formed by using a silane monomer. The silane monomer means a monomer in which a group capable of forming a hydroxy group (silanol group) by hydrolysis (hereinafter, referred to as “hydrolyzable group”) is bonded to a silicon atom. To do.

Here, in the present invention, it is preferable to use a silane monomer having a vinyl group as the silane monomer. By using a silane monomer having a vinyl group, a crosslinked structure can be formed between the siloxane skeleton and the vinyl polymer skeleton.
Hereinafter, in the present specification, the “vinyl group” includes a group having a carbon-carbon double bond in at least a part thereof in addition to the carbon-carbon double bond. Specifically, from a polymerizable carbon-carbon double bond and other functional groups such as a (meth)acryloyl group, a (meth)acryloxy group, an allyl group, an isopropenyl group, a vinylphenyl group and an isopropenylphenyl group. Constituent substituents are also included.

As the silane monomer having a vinyl group, a silane monomer (s1) in which at least one polymerizable group represented by the following general formula (s-1) is bonded to a silicon atom, and

[In the general formula (s-1), R ¹ represents a hydrogen atom or a methyl group, and R ² represents a single bond or a divalent aromatic hydrocarbon group. * Represents a bond with a silicon atom. ]
Examples thereof include a silane monomer (s2) having at least one polymerizable group represented by the following general formula (s-2) bonded to a silicon atom.

[In general formula (s-2), R< ¹ > is synonymous with the above. R ³ represents a divalent aliphatic hydrocarbon group. * Represents a bond with a silicon atom. ]

By using the silane monomer (s1), the density of the siloxane skeleton in the obtained polymer fine particles can be increased and the contact pressure can be improved. Further, by using the silane monomer (s2), it is possible to improve the dispersion stability of the seed particles, which will be described later, and it is possible to suppress the variation coefficient of the particle diameter of the obtained polymer fine particles. In the present invention, it is preferable to use the silane monomer (s1) alone or to include both the silane monomer (s1) and the silane monomer (s2). Thereby, the seed particles can be grown large while maintaining the hardness.

In the general formula (s-1), the aromatic hydrocarbon group represented by R ² preferably has 6 to 10 carbon atoms, and more preferably 6 to 8 carbon atoms. Specific examples thereof include a phenylene group, a methylphenylene group, a dimethylphenylene group and an ethylphenylene group, with a phenylene group being particularly preferred.
As R ² , a single bond or a phenylene group is preferable, and a single bond is particularly preferable.

Specific examples of the silane monomer (s1) include vinyltrialkoxysilane such as vinyltrimethoxysilane and vinyltriethoxysilane; vinyldialkoxysilane such as vinylmethyldimethoxysilane and vinylmethyldiethoxysilane; p- Examples thereof include styryltrialkoxysilanes such as styryltrimethoxysilane. Of these, vinyltrialkoxysilane and styryltrialkoxysilane are preferable, and vinyltrialkoxysilane is more preferable.

In the general formula (s-2), the aliphatic hydrocarbon group for R ³ is preferably linear, and may be linear or branched, and linear. preferable. Further, it preferably has 1 to 6 carbon atoms, and more preferably 1 to 5 carbon atoms. Specific examples thereof include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group and the like, an ethylene group, a propylene group and a butylene group are preferable, and a propylene group is particularly preferable.

As the silane monomer (s2), specifically, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane. (Meth)acryloyl group-containing trialkoxysilane such as 3-methacryloxyethoxypropyltrimethoxysilane; (meth)acryloyl group-containing dialkoxy such as 3-methacryloxypropylmethyldimethoxysilane and 3-methacryloxypropylmethyldiethoxysilane Silane; and the like. Of these, (meth)acryloyl group-containing trialkoxysilane is preferable, and 3-(meth)acryloxypropyltrimethoxysilane and 3-(meth)acryloxypropyltriethoxysilane are more preferable.

When the polymer fine particles of the present invention contain both the silane monomer (s1) and the silane monomer (s2), the mass ratio of the silane monomer (s1) and the silane monomer (s2) (silane single The ratio of the monomer (s1)/silane monomer (s2) is preferably 0.5 or more, more preferably 0.8 or more, further preferably 1.5 or more, particularly preferably 2.5 or more, Most preferably, it is 3 or more. The larger the mass ratio (silane monomer (s1)/silane monomer (s2)), the higher the hardness of the polymer particles obtained. The mass ratio (silane monomer (s1)/silane monomer (s2)) is preferably 10 or less, more preferably 8 or less, and further preferably 6 or less. By adjusting the mass ratio within this range, the coefficient of variation of particle diameter can be suppressed.

As the silane monomer, a silane monomer (s3) other than the silane monomer (s1) and the silane monomer (s2) may be used. Silane monomers are classified into crosslinkable silane monomers and non-crosslinkable silane monomers. The crosslinked structure formed by the crosslinkable silane monomer is one that crosslinks the organic polymer skeleton (for example, a vinyl polymer skeleton) and the organic polymer skeleton (first form; organic polymer crosslink); Those that crosslink the polysiloxane skeleton and the polysiloxane skeleton (second form; crosslink between polysiloxanes); those that crosslink the organic polymer skeleton and polysiloxane skeleton (third form; between the organic polymer and polysiloxane) Crosslinking); and the like.

Examples of the crosslinkable silane monomer capable of forming the first form (crosslinking between organic polymers) include silane compounds having two or more vinyl groups such as dimethyldivinylsilane, methyltrivinylsilane and tetravinylsilane. Can be mentioned. Examples of the crosslinkable silane monomer capable of forming the second form (crosslinking between polysiloxanes) include tetrafunctional silane monomer such as tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, and tetrabutoxysilane. Body; trifunctional silane-based monomers such as methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, and ethyltriethoxysilane. Further, as the crosslinkable silane monomer capable of forming the third form (organic polymer-polysiloxane crosslink), 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2 Di- or trialkoxysilane having an epoxy group such as -(3,4-epoxycyclohexyl)ethyltrimethoxysilane; Di- or trialkoxy having an amino group such as 3-aminopropyltrimethoxysilane or 3-aminopropyltriethoxysilane Silane; These crosslinkable silane monomers may be used alone or in combination of two or more.

Examples of the non-crosslinkable silane monomer include bifunctional silane-based monomers such as dialkylsilane such as dimethyldimethoxysilane and dimethyldiethoxysilane; trialkylsilane such as trimethylmethoxysilane and trimethylethoxysilane. Examples thereof include monofunctional silane-based monomers. These non-crosslinkable silane monomers may be used alone or in combination of two or more.

The total amount of the silane monomer (s1) and the silane monomer (s2) is preferably 80 parts by mass or more, more preferably 90 parts by mass or more, further preferably 100 parts by mass of the total amount of the silane monomers. Is 99 parts by mass or more, and particularly preferably 100 parts by mass.

The polymer fine particles of the invention preferably further contain a vinyl monomer (a monomer containing a vinyl group) as a polymer-forming component. Vinyl monomers are classified into crosslinkable vinyl monomers and non-crosslinkable vinyl monomers.

The crosslinkable vinyl monomer is a monomer having a vinyl group and capable of forming a crosslinked structure. Specifically, a monomer having two or more vinyl groups in one molecule (a vinyl monomer ( v1)) or a single vinyl group and a binding functional group other than vinyl group in one molecule (protonic hydrogen-containing group such as carboxy group and hydroxy group, terminal functional group such as alkoxy group). Examples thereof include a monomer (vinyl monomer (v2)). However, in order to form a crosslinked structure with the monomer (v2), it is necessary to have a counterpart monomer capable of reacting (bonding) with the bonding functional group of the monomer (v2).

Among the crosslinkable vinyl monomers, examples of the vinyl monomer (v1) (monomer having two or more vinyl groups in one molecule) include, for example, allyl (meth)acrylate and the like ( (Meth)acrylates; 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., polyalkylene glycol di(meth)acrylate (for example, diethylene glycol di(meth)acrylate) , Triethylene glycol di(meth)acrylate, decaethylene glycol di(meth)acrylate, pentadecaethylene glycol di(meth)acrylate, pentacontaethylene ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol Di(meth)acrylates such as di(meth)acrylate and polytetramethylene glycol di(meth)acrylate; tri(meth)acrylates such as trimethylolpropane tri(meth)acrylate; pentaerythritol tetra(meth)acrylate Such as tetra(meth)acrylates; hexa(meth)acrylates such as dipentaerythritol hexa(meth)acrylate; aromatic hydrocarbon crosslinking agents such as divinylbenzene, divinylnaphthalene, and their derivatives (preferably divinylbenzene) And other styrene-based polyfunctional monomers); heteroatom-containing cross-linking agents such as N,N-divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfonic acid; Among these, (meth)acrylates (polyfunctional (meth)acrylate) having two or more (meth)acryloyl groups in one molecule and aromatic hydrocarbon-based cross-linking agents (particularly styrene-based polyfunctional monomers) may be used. preferable. Among the styrenic polyfunctional monomers, a monomer having two vinyl groups in one molecule such as divinylbenzene is preferable. The vinyl monomer (v1) may be used alone or in combination of two or more kinds.

Examples of the vinyl monomer (v2) (a monomer having one vinyl group and a binding functional group other than a vinyl group in one molecule) among the crosslinkable vinyl monomers include (meth) Monomers having a carboxyl group such as acrylic acid; hydroxy group-containing (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate and 2-hydroxybutyl (meth)acrylate, p A monomer having a hydroxy group such as hydroxystyrene-containing styrenes such as hydroxystyrene; an alkoxy group such as 2-methoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, 2-butoxyethyl (meth)acrylate (Meth)acrylates, monomers having an alkoxy group such as alkoxystyrenes such as p-methoxystyrene; and the like. The vinyl monomer (v2) may be used alone or in combination of two or more kinds.

The non-crosslinkable vinyl monomer is a monomer having one vinyl group in one molecule (vinyl monomer (v3)), or the vinyl monomer in the case where the partner monomer is not present. The body (v2) (a monomer having one vinyl group in one molecule and a binding functional group other than the vinyl group) can be mentioned.

Among the non-crosslinkable vinyl monomers, the vinyl monomer (v3) (monomer having one vinyl group in one molecule) is a (meth)acrylate monofunctional monomer or a styrene monofunctional monomer. Monomers are included. Examples of the (meth)acrylate-based monofunctional monomer include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, 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 (meth)acrylate, 2-ethylhexyl (meth)acrylate Alkyl(meth)acrylates such as; cyclopropyl(meth)acrylate, cyclopentyl(meth)acrylate, cyclohexyl(meth)acrylate, cyclooctyl(meth)acrylate, cycloundecyl(meth)acrylate, cyclododecyl(meth)acrylate, Cycloalkyl (meth)acrylates such as isobornyl (meth)acrylate and 4-t-butylcyclohexyl (meth)acrylate; phenyl (meth)acrylate, benzyl (meth)acrylate, tolyl (meth)acrylate, phenethyl (meth)acrylate, etc. The aromatic ring-containing (meth)acrylates of are mentioned, and alkyl(meth)acrylates such as methyl(meth)acrylate are preferable. Styrene-based monofunctional monomers include styrene; alkylstyrenes such as o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, pt-butylstyrene; o-chlorostyrene, m-chloro. Examples thereof include halogen group-containing styrenes such as styrene and p-chlorostyrene, and styrene is preferable. The vinyl monomer (v3) may be used alone or in combination of two or more kinds.

The vinyl monomer preferably contains at least a crosslinkable vinyl monomer (v1) or a non-crosslinkable vinyl monomer (v3). It is more preferable to include a functional monomer or a styrene-based monofunctional monomer as the non-crosslinkable vinyl monomer (v3).

Furthermore, the content of the styrene-based monomer (styrene-based polyfunctional monomer and styrene-based monofunctional monomer) is preferably 60 parts by mass or more, more preferably 80 parts by mass or more, in 100 parts by mass of the vinyl monomer. It is more preferably 90 parts by mass or more, and for example, 100 parts by mass or less. When the content of the styrene-based monomer is within this range, the resulting polymer fine particles and conductive fine particles have good heat resistance.

The mass ratio of the vinyl monomer and the silane monomer used in the present invention (vinyl monomer/silane monomer) is 0 or more, preferably 0.1 or more, and more preferably 0.1. It is 2 or more, more preferably 0.25 or more, preferably 0.8 or less, more preferably 0.7 or less, and further preferably 0.6 or less.

When the silane monomer (s1) is used alone as the silane monomer, the proportion of the crosslinkable vinyl monomer (v1) in the vinyl monomer is, for example, 70% by mass or more, preferably 80% by mass. % Or more, more preferably 90% by mass or more, particularly preferably 95% by mass or more, and most preferably 100% by mass. At this time, the mass ratio of the crosslinkable vinyl monomer (v1) and the silane monomer (s1) (crosslinkable vinyl monomer (v1)/silane monomer (s1)) is 1 or less. It is preferably 0.7 or less, more preferably 0.5 or less, and for example, 0.01 or more.

When both the silane monomer (s1) and the silane monomer (s2) are contained as the silane monomer, the vinyl monomer is the crosslinkable vinyl monomer (v1) and/or the non-crosslinkable vinyl. The monomer (v3) is preferable, and the total proportion of the crosslinkable vinyl monomer (v1) and the non-crosslinkable vinyl monomer (v3) in the vinyl monomer is, for example, 70% by mass or more, preferably 80%. It is preferable that the content is at least mass%, more preferably at least 90 mass%, particularly preferably at least 95 mass%, and most preferably 100 mass%. At this time, the crosslinkable vinyl monomer (v1) and the non-crosslinkable vinyl monomer (v3) are preferably styrene-based monomers (styrene-based polyfunctional monomer and styrene-based monofunctional monomer), respectively. The total ratio of the silane monomer (s1) and the silane monomer (s2) in the silane monomer is, for example, 70% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and particularly It is preferably 95% by mass or more, and most preferably 100% by mass.

Further, in the present invention, the proportion of the crosslinkable monomer (crosslinkable silane monomer and crosslinkable vinyl monomer) in the total monomer (silane monomer/vinyl monomer) forming the polymer particles. Is preferably 1% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more. When the proportion of the crosslinkable monomer is within the above range, solvent resistance can be imparted to the obtained conductive fine particles, and for example, swelling or deformation of the particles due to the influence of the solvent when used for ACF formation can be prevented. it can. On the other hand, the upper limit of the proportion of the crosslinkable monomer is not particularly limited, but is preferably 95% by mass or less, more preferably 90% by mass or less, and further preferably 80% by mass or less. The proportion of the crosslinkable monomer is also preferably 100% by mass.

The polymer fine particles of the present invention are obtained by reacting a silane monomer and a vinyl monomer. For example, after the silane monomer is hydrolyzed and condensed to form seed particles, the seed particles are added to the seed particles. It can be preferably produced by absorbing a vinyl monomer (monomer having a vinyl group) and polymerizing the vinyl group (sol-gel seed polymerization method). In the present invention, the polymer fine particles produced by such a production method are referred to as seed polymer fine particles.

In forming the seed particles, a silane monomer may be brought into contact with water, a hydrophilic solvent such as methanol or ethanol, a catalyst (preferably a basic catalyst such as ammonia), or the like. As a result, the hydrolyzable group of the silane monomer is hydrolyzed to generate a hydroxy group (silanol group), and a plurality of hydroxy groups (silanol groups) are condensed, so that the siloxane bond (Si-O-Si) is formed. To form a polysiloxane skeleton (also referred to as a “polysiloxane component”).

When forming seed particles, it is preferable to stir the reaction liquid in order to prevent aggregation and obtain seed particles having a large particle size. The stirring power is preferably 0.0001~0.1kW / m ^3, more preferably 0.0003~0.05kW / m ^3, more preferably 0.0005~0.03kW / m ^3, in particular It is preferably 0.0007 to 0.02 kW/m ³ .

Then, the vinyl monomer is absorbed between the skeletons, and the vinyl group is polymerized in this state to form a vinyl polymer skeleton. As a result, polymer fine particles having a polysiloxane skeleton and a vinyl polymer skeleton can be obtained.

When these vinyl monomers are absorbed by the seed particles, the vinyl monomers may be directly absorbed by the seed particles, or the vinyl monomers are previously emulsified and dispersed in a solvent (preferably water). Alternatively, this may be mixed with seed particles. A publicly known emulsifier may be allowed to coexist during the emulsion dispersion.

Polymer fine particles can be obtained by polymerizing (preferably radical polymerization) the vinyl monomer absorbed by the seed particles.
The obtained polymer fine particles may be further heat-treated. In the polymer fine particles, unreacted hydroxy groups and alkoxy groups derived from the silane monomer may remain, and by heat treating the polymer fine particles, the remaining hydroxy groups and alkoxy groups are hydrolyzed. -Because of condensation, the density of the polysiloxane skeleton in the polymer fine particles can be further improved.

The heat treatment is preferably performed in air or an inert gas (for example, nitrogen gas), more preferably nitrogen gas. The heat treatment temperature is preferably 200° C. or higher, more preferably 250° C. or higher, even more preferably 270° C. or higher. Further, the heat treatment temperature is preferably lower than the thermal decomposition temperature of the polymer particles, for example, preferably 400° C. or lower, more preferably 370° C. or lower. The heat treatment time is preferably 0.3 hours or longer, more preferably 0.5 hours or longer, still more preferably 0.7 hours or longer, preferably 10 hours or shorter, more preferably 5 hours or shorter, still more preferably 3 hours. It is as follows.

(Conductive particles)
In the conductive fine particles of the present invention, at least one conductive metal layer is formed on the surface of the polymer fine particles as the base particles.

Examples of the metal forming the conductive metal layer include gold, silver, copper, platinum, iron, lead, aluminum, chromium, palladium, nickel, rhodium, ruthenium, antimony, bismuth, germanium, tin, cobalt, indium and nickel. -Phosphorus, nickel-boron, and other metals, metal compounds, and alloys thereof are included. Among these, gold, nickel, palladium, silver, copper, and tin are preferable because they become conductive fine particles having excellent conductivity. In addition, at low cost, nickel, nickel alloys (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 alloys (Cu and Fe, Co, Ni, Zn, Sn, In, Ga, Tl, Zr, W, Mo, Rh, Ru, Ir, Ag, An alloy with at least one metal element selected from the group consisting of Au, Bi, Al, Mn, Mg, P and B, preferably an alloy with Ag, Ni, Sn and Zn); silver, a silver alloy (Ag And Fe, Co, Ni, Zn, Sn, In, Ga, Tl, Zr, W, Mo, Rh, Ru, Ir, Au, Bi, Al, Mn, Mg, P, B. Alloy with one kind of metal element, preferably Ag-Ni, Ag-Sn, Ag-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, etc.) are preferable. Of these, nickel and nickel alloys are preferable. 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 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, 0.30 μm or less, more preferably 0.25 μm or less, It is more preferably 0.20 μm or less, and even more preferably 0.15 μm or less. The thickness of the conductive metal layer can be measured, for example, by the method described later in Examples.

The conductive metal layer may cover at least a part of the surface of the resin particles, but the surface of the conductive metal layer is substantially cracked or a surface on which the conductive metal layer is not formed. Is preferably absent. Here, "a surface on which no substantial cracks or conductive metal layer is formed" means that the surface of any 10,000 conductive fine particles is observed using a scanning electron microscope (magnification: 1000 times). In addition, it means that the cracking of the conductive metal layer and the exposure of the resin particle surface are not substantially visually observed.

The number average particle diameter of the conductive fine particles of the present invention is preferably 5.1 μm or more, more preferably 5.6 μm or more, still more preferably 6.1 μm or more, and preferably 15.6 μm or less, more preferably 13. It is 1 μm or less, more preferably 12.1 μm or less, and even more preferably 11.1 μm or less. If the number average particle diameter is within this range, it can be suitably used for electrical connection of finely and narrowed electrodes and wirings. The coefficient of variation (CV value) of the particle diameter of the conductive fine particles is preferably 10.0% or less, more preferably 9.0% or less, and further preferably 8.0% or less. The coefficient of variation of particle diameter is a value calculated according to the following formula.
Coefficient of variation of particle size (%)=100×(standard deviation of particle size/number average particle size)
As the number average particle size of the conductive fine particles, the number-based average particle size of 3000 particles was determined by using a flow type particle image analyzer (“FPIA (registered trademark)-3000” manufactured by Sysmex Corporation). Is preferably adopted.

The conductive fine particles of the present invention may have an insulating resin layer on at least a part of the surface. That is, it may be a mode in which an insulating resin layer is further provided on the surface of the conductive metal layer. When the insulating resin layer is further laminated on the conductive metal layer on the surface as described above, it is possible to prevent lateral conduction which is likely to occur when forming a high-density circuit or connecting terminals.
The insulating resin layer is not particularly limited as long as the insulating property between the particles of the conductive fine particles can be ensured and the insulating resin layer can be easily collapsed or peeled by a constant pressure and/or heating, For example, polyolefins such as polyethylene; (meth)acrylate polymers and copolymers such as polymethyl (meth)acrylate; polystyrene; thermoplastic resins such as polystyrene and their crosslinked products; epoxy resins, phenol resins, amino resins (melamine resins, etc.) And the like; water-soluble resins such as polyvinyl alcohol and mixtures thereof; and the like. However, if the insulating resin layer is too hard as compared with the base particles, the base particles themselves may be destroyed before the destruction of the insulating resin layer. Therefore, it is preferable to use an uncrosslinked resin or a resin having a relatively low degree of crosslinking 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 insulating, granular, spherical, lump-like, or scale-like particles are attached to the surface of the conductive metal layer. It may be present, or may be a layer formed by chemically modifying the surface of the conductive metal layer, or may be a combination thereof. The thickness of the insulating resin layer is preferably 0.01 μm to 1 μm, more preferably 0.02 μm or more and 0.5 μm or less, still more 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 insulating property between the particles becomes good while maintaining the good conduction property by the conductive fine particles.

The method for forming the conductive metal layer and the method for forming the insulating resin layer are not particularly limited. For example, the conductive metal layer is formed by plating the surface of the base material by electroless plating or electrolytic plating; Can be formed by 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 the conductive metal layer can be easily formed without requiring a large-scale device.

(Anisotropic conductive material)
The anisotropic conductive material of the present invention contains the conductive fine particles of the present invention and a binder resin, and the conductive fine particles are dispersed in the 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. Providing these anisotropic conductive materials between the opposing substrates or between the electrode terminals enables good electrical connection. 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 its composition).

The binder resin is an insulating resin, for example, a thermoplastic resin such as an acrylic resin, an ethylene-vinyl acetate resin, or a styrene-butadiene block copolymer; a curing agent such as a monomer or oligomer having a glycidyl group, or an isocyanate. A curable resin composition that is cured by a reaction with; a curable resin composition that is cured by light or heat; and the like.
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. The conductive fine particles may be present together with the binder resin between the base materials to be connected and between the electrode terminals for connection.

In the anisotropic conductive material of the present invention, the content of the conductive fine particles may be appropriately determined depending on the application, but for example, it is preferably 1% by volume or more, and more preferably 2% by volume based on the total amount of the anisotropic conductive material. The content is preferably not less than 5% by volume, more preferably not less than 50% by volume, more preferably not more than 30% by volume, still more preferably not more than 20% by volume. If the content of the conductive fine particles is too small, it may be difficult to obtain sufficient electrical conduction, 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, anisotropy In some cases, it may be difficult to exhibit the function as a conductive material.

Regarding the film thickness of the anisotropic conductive material of the present invention, the coating thickness of the paste or the 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 electrodes to be connected In consideration of the above, it is preferable that the conductive fine particles are sandwiched between the electrodes to be connected, and that the voids between the bonding substrates on which the electrodes to be connected are formed be sufficiently filled with the binder resin layer. ..

Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to the following Examples, and may be appropriately modified within a range compatible with the gist of the preceding and the following. Of course, it is possible to carry out, and all of them are included in the technical scope of the present invention. In the following, "part" means "part by mass" and "%" means "% by mass" unless otherwise specified.

1. Physical property measurement methods Various physical properties were measured by the following methods.
<Number average particle size and coefficient of variation (CV value) of seed particles and polymer particles>
In the case of polymer fine particles, 1 part of polyoxyethylene alkyl ether sulfate ammonium salt (“Hitenol (registered trademark) N-08” manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) was added to 0.1 part of the polymer fine particles. % Aqueous solution of 20 parts and ultrasonically dispersed for 10 minutes is used as a measurement sample. In the case of seed particles, the dispersion obtained by hydrolysis and condensation reaction is polyoxyethylene alkyl ether sulfate ammonium salt. (Daiichi Kogyo Seiyaku Co., Ltd. "Hitenol (registered trademark) N-08") diluted with a 1% aqueous solution is used as a measurement sample by a particle size distribution measuring device ("Beckman Coulter Coulter Multisizer III"). The particle diameter (μm) of 30,000 particles was measured to determine the number average particle diameter. With respect to the polymer fine particles, the standard deviation of the particle size on a number basis was also obtained together with the number average particle size, and the coefficient of variation (CV value) of the particle size was calculated according to the following formula.
Coefficient of variation of particle size (%)=100×(standard deviation of particle size/number average particle size)

<Thickness of conductive metal layer>
Using a flow-type particle image analyzer (“FPIA (registered trademark)-3000” manufactured by Sysmex Corporation), 3000 base particles (polymer fine particles) have a number average particle diameter X (μm) and 3000 conductive fine particles. The number average particle diameter Y (μm) was measured. In addition, 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 Co., Ltd.), which is an emulsifier, to 0.25 parts of the particles, and ultrasonically. It was carried out after dispersing for 10 minutes. Then, the thickness of the conductive metal layer was calculated according to the following formula.
Conductive metal layer film thickness (μm)=(Y−X)/2

<10% K value of polymer fine particles>
Using a micro compression tester (“MCT-W500” manufactured by Shimadzu Corporation), at room temperature (25° C.), a circular flat plate indenter having a diameter of 50 μm was used for one particle dispersed on a sample table (material: SKS flat plate). Using (material: diamond), a load is applied to the center of the particle at a constant load speed (2.2786 N/sec), and the load value (mN) when the compressive displacement becomes 10% of the particle diameter and its The amount of displacement (μm) at that time was measured. The measurement was performed on 10 different particles for each sample, and the averaged value was used as the measured value. Then, the obtained 10% compression load value (mN) is converted into a compression load (N), the displacement amount (μm) obtained at that time is converted into a compression displacement (mm), and the average particle diameter of the polymer fine particles is calculated. The radius (mm) of the particles was calculated from (μm), and the calculated radius was calculated based on the following formula. The above measurement was carried out in a constant temperature atmosphere of 25°C.

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

<Initial resistance of connection structure>
The initial resistance value between the electrodes of the obtained connection structure was measured, and when the initial resistance value was 5Ω or less, it was evaluated as “◯”, and when it exceeded 5Ω, it was evaluated as “x”.
<Connection reliability of connection structure>
After the obtained connection structure was left in an atmosphere of 85° C. and 85% RH for 500 hours, the resistance value was measured in the same manner as in the evaluation of the initial resistance. When the initial resistance value is a and the resistance value measured after 500 hours is b, the resistance value increase rate (%) calculated based on the following formula is 3% or less, "○", and when it exceeds 3%. It was evaluated as "x".
Resistance increase rate (%)=[(b−a)/a]×100

2. Manufacturing of conductive fine particles 2-1. Preparation of base material (polymer fine particles) (Production Example 1)
A four-necked flask equipped with a cooling tube, a thermometer, and a dropping port was charged with 572.6 parts of ion-exchanged water, 0.9 parts of 25% ammonia water, and 282.1 parts of methanol and kept at 25°C. 20.1 parts of 3-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., "KBM503") as a silane monomer (seed-forming monomer) under stirring, vinyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd.) Manufactured by "KBM1003") 80.4 parts, and subjected to hydrolysis and condensation reaction of 3-methacryloxypropyltrimethoxysilane and vinyltrimethoxysilane while stirring to give a polymerizable polysiloxane particle having a methacryloyl group ( A dispersion of seed particles) was prepared. The stirring power was 0.0035 kW/m ³ . The number-based average particle diameter of the obtained polysiloxane particles was 5.99 μm, and the coefficient of variation of particle diameter was 3.0%.

Then, 0.8 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 100 parts of ion-exchanged water. In the above solution, 30.1 parts of styrene as a vinyl monomer (absorption monomer) and 2,2′-azobis(2,4-dimethylvaleronitrile) (“V-65” manufactured by Wako Pure Chemical Industries, Ltd.) A solution in which 3 parts was dissolved was added and emulsified and dispersed to prepare an emulsion of the monomer component (absorption monomer). Two hours after the start of emulsification and dispersion, the obtained emulsion was added to the 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 absorbed the absorbing monomer and were enlarged.

Then, 5.6 parts of a 20% aqueous solution of polyoxyethylene styrenated phenyl ether sulfate ammonium salt (“Hitenol (registered trademark) NF-08” manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) was added, and the reaction solution was added under a nitrogen atmosphere. The temperature was raised to 65° C., and the temperature was maintained at 65° C. for 2 hours to carry out radical polymerization of the monomer component. The emulsion after radical polymerization is subjected to solid-liquid separation, the obtained cake is washed with ion-exchanged water and methanol, and then baked under a nitrogen atmosphere at a heat treatment temperature of 320° C. for 1 hour to obtain polymer fine particles (1). It was The physical properties of the obtained polymer fine particles are as shown in Table 1.

(Production Examples 2 to 9)
The type and amount of silane monomer used are shown in Table 1, and the amount of ion-exchanged water, methanol, and ammonia water was appropriately changed to prepare seed particles. Thereafter, polymer fine particles (2) to (9) were obtained in the same manner as in Production Example 1 except that the type and amount of the vinyl monomer used and the heat treatment temperature were as shown in Table 1. The physical properties of the obtained polymer fine particles are as shown in Table 1. In Production Examples 6 to 9, since the polymer fine particles were decomposed when the heat treatment temperature was 320° C., the heat treatment temperature was 120° C.

In Table 1, KBM1403 means p-styryltrimethoxysilane, St means styrene, DVB means divinylbenzene, MMA means methyl methacrylate, and DPE-A means dipentaerythritol hexaacrylate. Shall mean.

2-2. Preparation of conductive fine particles (formation of conductive metal layer)
(Example 1)
By using the polymer fine particles (1) as a base material, subjecting the base material to etching treatment with sodium hydroxide, contacting with a tin dichloride solution for sensitizing, and then immersing in a palladium dichloride solution Palladium nuclei were formed by the activating method (sensitizing-activating method). Next, 2 parts of the polymer fine particles having palladium nuclei were added to 400 parts of ion-exchanged water and subjected to an ultrasonic dispersion treatment, and then the obtained polymer fine particle suspension was heated in a 70° C. hot bath. did. By adding 300 parts of the electroless plating solution (“Sumer (registered trademark) S680” manufactured by Nippon Kanigen Co., Ltd.) separately heated to 70° C. in the state where the suspension is heated, electroless nickel is added. A plating reaction occurred. 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 plated particles were added to a displacement gold plating solution containing potassium gold cyanide, and the surface of the nickel layer was further plated with gold to obtain conductive fine particles. The thickness of the conductive metal layer in the obtained conductive fine particles was 0.12 μm.

(Examples 2-5, Comparative Examples 1-4)
Conductive fine particles were produced in the same manner as in Example 1 except that the polymer fine particles shown in Table 1 were used as the base material. The thickness of the conductive metal layer in the obtained conductive fine particles was 0.12 μm in all examples.

3. Preparation and Evaluation of Anisotropic Conductive Material Using the conductive fine particles obtained in Examples and Comparative Examples, 2.0 parts of the conductive fine particles were added to an epoxy resin (Mitsui Chemicals, Inc.) as a binder resin by using a rotation and revolution type stirrer. "Structbond (registered trademark) XN-5A" manufactured by 100 parts was added, and the mixture was stirred for 10 minutes to be dispersed to obtain a conductive paste.
The obtained anisotropic conductive paste is sandwiched between a glass substrate on which ITO electrodes are wired at a pitch of 100 μm and a glass substrate on which an aluminum pattern is formed at a pitch of 100 μm, and thermocompression bonded under a pressure bonding condition of 2 MPa and 150° C. At the same time, the binder resin was cured to obtain a connection structure. The initial resistance value of the obtained anisotropic conductive material (anisotropic conductive paste) was evaluated by the above method. The evaluation results are shown in Table 2.

As shown in Table 2, the polymer fine particles have a number average particle diameter of 5 μm or more and 15 μm or less, a number-based particle diameter variation coefficient (CV value) of 10% or less, and a specific hardness. It is understood that by using the polymer fine particles, conductive fine particles excellent in both initial resistance value and connection reliability and an anisotropic conductive material can be obtained.

The polymer fine particles of the present invention have a number average particle size of 5 μm or more and 15 μm or less, a coefficient of variation (CV value) of the number-based particle size of 10% or less, contain a specific amount of Si, and have a specific amount of Since it has a K value of 10%, the conductive fine particles obtained using it have excellent initial resistance and connection reliability. It is extremely useful for anisotropic conductive materials such as conductive conductive adhesives and anisotropic conductive inks.

Claims (6)

The number average particle diameter is 5 μm or more and 15 μm or less,
The coefficient of variation (CV value) of the number-based particle diameter is 10% or less,
Si content is 12% by mass or more and 35% by mass or less,
A polymer of a monomer composition containing a vinyl monomer and a silane monomer in a mass ratio (vinyl monomer/silane monomer) of 0.2 or more and 0.8 or less,
The vinyl monomer is a styrene-based polyfunctional monomer, or a styrene-based monofunctional monomer,
The silane monomer has the following general formula (s-1)
[In the general formula (s-1), R ¹ represents a hydrogen atom or a methyl group, and R ² represents a single bond or a divalent aromatic hydrocarbon group. * Represents a bond with a silicon atom. ]
A silane monomer (s1) which is an alkoxysilane having at least one polymerizable group represented by
When the compression elastic modulus when the diameter of the polymer particles is displaced by 10% is set to 10% K value, the polymer particles having a 10% K value of 4500 (N/mm ² ) or more (provided that the organic component is carbonized Excluding the ones). The following general formula (s-1)
[In the general formula (s-1), R ¹ represents a hydrogen atom or a methyl group, and R ² represents a single bond or a divalent aromatic hydrocarbon group. * Represents a bond with a silicon atom. ]
A silane monomer (s1), which is an alkoxysilane in which at least one polymerizable group represented by: is bonded to a silicon atom, and
The following general formula (s-2)
[In general formula (s-2), R< ¹ > is synonymous with the above. R ³ represents a linear or branched divalent aliphatic hydrocarbon group. * Represents a bond with a silicon atom. ]
Polymer fine particles obtained by polymerizing a seed particle obtained from a silane monomer (s2) which is an alkoxysilane having at least one polymerizable group represented by
The vinyl monomer is a styrene-based polyfunctional monomer, or a styrene-based monofunctional monomer,
The mass ratio of the vinyl monomer and the silane monomer (vinyl monomer/silane monomer) (however, the silane monomer includes the silane monomer (s1) and the silane monomer (s2)) 0.2 or more and 0.8 or less,
Si content is 12% by mass or more and 35% by mass or less,
Seed polymer fine particles having a number average particle diameter of 5 μm or more and 15 μm or less (excluding those obtained by carbonizing an organic component). The polymer fine particles according to claim 1 or 2, wherein a 10% K value, which is a compression elastic modulus when the diameter of the polymer fine particles is displaced by 10%, is 12000 (N/mm ² ) or less. The polymer fine particles according to any one of claims 1 to 3, which are used as a base material for conductive fine particles. Conductive fine particles having a conductive metal layer on the surface of the polymer fine particles according to claim 1. An anisotropic conductive material containing the conductive fine particles according to claim 5.