JP6498505B2 - Conductive fine particles and anisotropic conductive material using the same - Google Patents

Description

  The present invention relates to conductive fine particles having protrusions and an anisotropic conductive material using the same.

  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 dispersed in a binder resin or the like. For example, anisotropic conductive paste (ACP), anisotropic conductive film (ACF), anisotropic conductive ink, anisotropic conductive There are sheets. As the conductive fine particles used for this anisotropic conductive material, those obtained by coating the surface of resin particles as a substrate with a conductive metal layer in addition to metal particles are used. The conductive fine particles composed of the resin particles and the conductive metal layer are electrically connected between electrodes and wirings by a conductive metal layer formed on the surface.

  At this time, attempts have been made to form protrusions on the surface of the conductive fine particles in order to ensure sufficient connection reliability. For example, Patent Document 1 describes a method of forming microprotrusions at the same time when a nickel or nickel alloy film is formed on the surface of spherical core particles by an electroless plating method. However, this method uses abnormal deposition of plating, and it was necessary to control the electroless plating conditions to a special condition in order to form microprotrusions, so the shape of microprotrusions is controlled within a certain range. Sometimes it was difficult. Patent Document 2 describes a method of forming protrusions by adsorbing non-conductive inorganic particles to a plastic core and forming a metal plating layer. In this method, When the adsorption power of the non-conductive inorganic particles is not sufficient, the protrusions are likely to drop off, and sufficient connection reliability may not be ensured.

Japanese Patent No. 3696429 Japanese Patent No. 4640531

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide conductive fine particles that can prevent protrusions from being removed and can ensure sufficient connection reliability regardless of plating conditions.

  As a result of intensive investigations to solve the above problems, the present inventors have made conductive fine particles, in which protrusion detachment has been suppressed, by using resin particles having specific convex portions as substrate particles, as plating conditions. The present invention was completed by finding that it can be formed regardless.

That is, the conductive fine particles of the present invention that can achieve the above-mentioned object are the resin particles having a plurality of convex portions on the surface and the conductive metal that covers the surface convex portions of the resin particles along the convex shape. Conductive particles having a layer, wherein the resin particles are resin particles composed of a peripheral portion having a plurality of convex portions on the surface and a spherical portion surrounded by the peripheral portion, and When the cross section of the resin particle is observed with a transmission electron microscope, the center of curvature of the boundary line between the peripheral portion and the spherical portion exists in the spherical portion. The contact angle of the convex part is preferably 30 ° or more and 90 ° or less on average. The ratio of the average height of the protrusions to the volume average particle diameter of the resin particles (average height of the protrusions / volume average particle diameter of the resin particles) is 0.001 or more and 0.20 or less. Is preferred.
The variation coefficient of the number of convex portions per one resin particle is preferably 20% or less. Further, in the scanning electron microscope image of the resin particle, two straight lines perpendicular to each other are drawn at the center of the resin particle to divide the resin particle into four sections, and the standard number of protrusions per section for each resin particle. When the deviation is calculated and this standard deviation is divided by the number of convex portions per resin particle, the average value is preferably 10% or less. The volume average particle diameter of the conductive fine particles of the present invention is preferably 1 μm or more and 50 μm or less.
Furthermore, an anisotropic conductive material containing the conductive fine particles of the present invention is also included in the technical scope of the present invention.

  Since the conductive fine particles of the present invention use resin particles having specific convex portions as the base particles, the shape of the protrusions on the surface of the conductive fine particles can be controlled and the detachment of the protrusions is suppressed.

1 (a) and 1 (b) are schematic views of protrusions on the cross section of the resin particle of the present invention. 2 (a) and 2 (b) are schematic views of protrusions on the cross section of the resin particle of the present invention. It is a figure for demonstrating the height and base (diameter) of a convex part. 3 (a) and 3 (b) are schematic views of protrusions on the cross section of the resin particle of the present invention. It is a figure for demonstrating the contact angle of a convex part. FIG. 4 is a scanning electron micrograph (magnification: 4,000 times) of the resin particles of Production Example 1. FIG. 5 is a scanning electron micrograph (magnification 3,500 times) of the resin particles of Production Example 2. FIG. 6 is a scanning electron micrograph (magnification: 3,000 times) of the resin particles of Production Example 3. FIG. 7 is a scanning electron micrograph (magnification 3,700 times) of the resin particles of Production Example 8. FIG. 8 is a transmission electron micrograph (magnification 10,000 times) of the cross section of the resin particle of Production Example 3. FIG. 9 is a transmission electron micrograph (magnification of 5,000 times) of the cross section of the resin particle of Production Example 8. 10 is a scanning electron micrograph (magnification 3,500 times) of the conductive fine particles of Example 2. FIG.

  The conductive fine particles of the present invention are composed of resin particles as base particles and a conductive metal layer covering the surface of the resin particles.

(Resin particles)
The resin particles used as the base particles of the conductive fine particles of the present invention are resin particles having a plurality of convex portions on the surface, and are composed of a spherical portion and a peripheral portion. The peripheral portion is formed on the surface of the spherical portion, and the spherical portion is surrounded by the peripheral portion. And a peripheral part has the said some convex part. When the cross section of the resin particle is observed with a transmission electron microscope, the center of curvature of the boundary line between the peripheral portion and the spherical portion exists in the spherical portion. This makes it difficult for the convex portion to be detached. As will be described later, in the transmission electron micrograph of the resin particle cross section, the peripheral portion is usually displayed as a dark color portion and the spherical portion is displayed as a light color portion.

  Hereinafter, the structure of the resin particles will be described with reference to the drawings. FIGS. 1A and 1B are schematic views of protrusions on a resin particle cross section. As shown to Fig.1 (a), the peripheral part (2a) which has a convex part (3) exists in the surface of a spherical part (1), Between a spherical part (1) and a peripheral part (2a) The boundary line (10) has the center of curvature in the spherical portion (1). The fact that the center of curvature of the boundary line (10) exists in the spherical part (1) means that the boundary line (10) is convex toward the peripheral part side. Furthermore, the peripheral part (2a) may be comprised by the peripheral layer (2b) and the convex part (3).

  Moreover, the said peripheral part (2a) does not have a peripheral layer (2b) (namely, the thickness of a peripheral layer (2b) is 0 micrometer), and may be comprised only by a convex part (3). Good. Even in such a case, as shown in FIG. 1B, the peripheral portion (2a) having the convex portion (3) is present on the surface of the spherical portion (1), and the spherical portion (1) and the peripheral portion The boundary line (10) between the parts (2a) has a center of curvature in the spherical part (1).

  The spherical portion alone is preferably a spherical shape having no protrusion, and more preferably a true spherical shape. The presence of the center of curvature of the boundary line between the peripheral edge and the spherical part in the resin particle cross section in the spherical part means that the boundary line is a straight line or a curve, and that the bending is directed to the peripheral part side (to the outside). means. The curvature of the curve is defined as the radius of the contact circle of the curve (curvature radius), the curvature radius of the boundary line between the peripheral edge portion and the spherical portion, and the change rate of the radius of the spherical portion (curvature radius− The absolute value of the radius of the spherical part) / the radius of the spherical part) is preferably within 10%, more preferably within 5%. In addition, when the resin particles are cut and the cross section is taken out, the resin particles may be subjected to compressive stress, and even if the spherical part is a perfect sphere, the boundary line of the spherical part in the transmission electron micrograph is a perfect circle. Sometimes not.

In the periphery of the resin particle, the convex portion is a product of height (μm) and bottom diameter (μm), that is, height × bottom diameter (μm ² ) is 0.001 (μm ² ) or more. means. The product of the height and the bottom diameter is more preferably 0.005 (μm ² ) or more, and further preferably 0.009.
(Μm ² ) or more. Although an upper limit is not specifically limited, Usually, it is 50 (micrometer < ² >) or less.

  The convex portion preferably has an average contact angle (contact angle with respect to the peripheral layer or the spherical portion when the convex portion is assumed to be a droplet) of, for example, 90 ° or less. The smaller the contact angle, the more difficult the protrusions are detached. Therefore, it is more preferably 85 ° or less, further preferably 80 ° or less, and particularly preferably 70 ° or less. Moreover, since the connection stability improvement effect by a convex part can be exhibited more effectively, so that the said contact angle is large, it is preferable that it is 30 degrees or more, More preferably, it is 35 degrees or more, More preferably, it is 45 degrees. That's it.

  The convex contact angle can be defined as an angle formed by the tangent of the peripheral layer or the spherical portion and the tangent of the convex portion at the starting point of the convex portion. Can be measured based on. Specifically, a cross-section of the resin particle was photographed with a transmission electron microscope at a magnification of 10,000 times or more, and based on the obtained transmission electron micrograph, the peripheral edge passing through one starting point (6a) of the convex portion (3) The angle (θ) formed by the tangent (9a) to the surface of the part (spherical part when the peripheral layer cannot be confirmed in the transmission electron micrograph) and the tangent (9b) to the convex part passing through the starting point (6a) Let it be a corner (FIGS. 3A and 3B). Furthermore, about 10 or more convex parts of one type of resin particles, the contact angle can be measured by the above method and averaged to be the contact angle for each resin particle.

  The average height of the convex portions is preferably 0.05 μm or more and 5 μm or less. The higher the average height of the protrusions, the more reliably the connection stability improvement effect by the protrusions can be exhibited. Therefore, the average height of the protrusions is more preferably 0.10 μm or more, and further preferably 0.12 μm or more. Further, the lower the average height of the convex portions, the harder the convex portions are detached. Therefore, the average height of the convex portions is more preferably 5.0 μm or less, further preferably 4.5 μm or less, and even more preferably 4.0 μm or less.

  The resin particles preferably have an average bottom diameter of convex portions of 0.10 μm or more and 10 μm or less. More preferably, it is 0.12 micrometer or more, More preferably, it is 0.15 micrometer or more. The larger the average bottom diameter of the convex portion, the larger the contact area between the spherical portion and the convex portion, so that the convex portion is less likely to be detached. Further, the smaller the average bottom diameter of the convex portion, the more effectively the effect of improving the connection stability by the convex portion can be exhibited even when the particle diameter of the resin particles is reduced. Therefore, it is more preferably 9.0 μm or less, and still more preferably 8.0 μm or less.

  The resin particles preferably have a ratio (height / bottom diameter) of the average height of the protrusions to the average bottom diameter (height / bottom diameter) of 0.10 or more and 0.80 or less. The larger the ratio (height / bottom diameter), the more effectively the effect of improving the connection stability by the convex portion can be exhibited. Therefore, it is more preferably 0.15 or more, and still more preferably 0.20 or more. Further, when the ratio (height / bottom diameter) is small, the protrusions are more difficult to be detached. Therefore, it is more preferably 0.70 or less, and still more preferably 0.60 or less.

  Furthermore, the resin particles preferably have a ratio of the average height of the protrusions to the volume average particle diameter of the resin particles (average height of the protrusions / volume average particle diameter) of 0.001 or more and 0.20 or less. . The larger the ratio (average height of protrusions / volume average particle diameter), the more effectively the effect of improving the connection stability by the protrusions can be exhibited. Therefore, it is more preferably 0.003 or more, and further preferably 0.005 or more. Further, when the ratio (average height of convex portions / volume average particle diameter) is small, the detachment of the protrusions is further suppressed. Therefore, it is more preferably 0.19 or less, and still more preferably 0.18 or less.

  The average height and the average bottom diameter of the convex portions can be measured based on a scanning electron micrograph taken at a magnification of 10,000 times or more. Specifically, the resin particles were photographed with a scanning electron microscope at a magnification of 10,000 times or more, and in the obtained scanning electron micrographs, as shown in FIGS. 2 (a) and 2 (b), the periphery of the resin particles A triangle (4) having a line segment connecting two starting points (6a, 6b) of the convex part (3) existing in the part (2a) as a base, and a top part (8) of the convex part (3) as a vertex. Draw. The base (5) of the triangle (4) is defined as the base of the convex portion (3), and the height of the triangle (4) is defined as the height of the convex portion (3). Furthermore, about 50 or more convex parts of the resin particle, the height and the bottom diameter are measured by the above-described method, and averaged to obtain the average height and the average bottom diameter of the convex part of each resin particle, respectively.

  In the resin particles of the present invention, the number of convex portions per resin particle is preferably 5 or more and 5000 or less. As the number of convex portions per resin particle increases, the distribution density of the convex portions becomes more uniform, and the effect of improving the connection stability by the convex portions can be more effectively exhibited. Therefore, it is more preferably 7 or more, and still more preferably 10 or more. Moreover, since the contact area of a convex part and a spherical part can be enlarged, so that the number of convex parts per resin particle is small, detachment | desorption of a convex part can be suppressed further. Accordingly, the number is more preferably 4000 or less, and still more preferably 3500 or less.

  The number of convex portions per resin particle can be measured based on a scanning electron micrograph taken at a magnification of 3000 times or more. Specifically, for each resin particle, the number of protrusions present on the observation surface side of the scanning electron micrograph is doubled to be the number of protrusions per resin particle. For the five resin particles per resin particle, the number of convex portions is measured by the method described above, and the average is taken as the number of convex portions per resin particle.

  Moreover, according to this invention, it is also possible to arrange | equalize the number of the convex parts per resin particle. The coefficient of variation of the number of convex portions per resin particle can be, for example, 20% or less, preferably 18% or less, more preferably 15% or less, and can suppress variation between resin particles. Performance can be made uniform. The coefficient of variation is usually preferably 0.1% or more, more preferably 1% or more, and further preferably 2% or more.

  Furthermore, according to the present invention, the convex portions can be formed evenly on the surface of the resin particles, and the performance of the conductive fine particles can be made uniform. Specifically, in a scanning electron microscope image of the resin particles (for example, an enlargement magnification of 3000 times or more), the resin particles are divided into four sections by drawing two straight lines that pass through the center of the resin particles and are orthogonal to each other at the particle center. Dividing and calculating the standard deviation of the number of convex parts per section for one resin particle, and dividing this standard deviation by the number of convex parts per resin particle, the average value is For example, it can be 10% or less, preferably 8% or less, more preferably 7% or less. The average value is usually preferably 0.01% or more, more preferably 0.1% or more, and further preferably 0.2% or more.

The resin particles preferably have a convex number density of 0.01 / μm ² or more and 10 / μm ² or less. As the number density of the convex portions is larger, the distribution of the convex portions becomes more uniform, and the effect of improving the connection stability by the convex portions can be more effectively exhibited. Therefore, it is more preferably 0.015 / μm ² or more, and further preferably 0.02 / μm ² or more. Moreover, since the contact area of a convex part and a spherical part can be enlarged, so that the number density of a convex part is small, detachment | desorption of a convex part can be suppressed further. Therefore, it is more preferably 8.0 pieces / μm ² or less, still more preferably 7.0 pieces / μm ² or less. The number density of the convex portions means the number of convex portions existing per 1 μm ² of the area of the spherical portion or the peripheral layer.

  The number density of the convex portions in the resin particles can be calculated based on the radius of the spherical portion or the sum of the radius of the spherical portion and the thickness of the peripheral layer, and the number of convex portions per resin particle. Specifically, using a scanning electron micrograph taken at a magnification of 10,000 or more, use the caliper diameter calculation tool attached to the device to calculate the diameter of the spherical part or the diameter including the spherical part and the peripheral layer. The number of protrusions per resin particle is the surface area of the spherical part (4 × π × square of the radius of the spherical part) or the surface area of the peripheral layer (4 × π × (the radius of the spherical part and the thickness of the peripheral layer). It can be calculated by dividing by the square of the sum).

  Moreover, when the said peripheral part is comprised by the convex part and the peripheral layer, when observed with a transmission electron microscope, it is preferable that it is 5 micrometers or less, for example, and the thickness of a peripheral layer is 3 micrometers or less. More preferably, it is 1 μm or less. The lower limit of the thickness of the peripheral layer may preferably be 0 μm.

  In the peripheral portion, if the thickness of the peripheral portion is the sum of the average height of the convex portions and the thickness of the peripheral layer, the peripheral portion preferably has a thickness of 10 μm or less, more preferably 9 μm or less, and even more preferably. 8 μm or less. Moreover, it is preferable that the thickness of a peripheral part is 0.10 micrometer or more, More preferably, it is 0.11 micrometer or more, More preferably, it is 0.12 micrometer or more.

  Further, the ratio of the average height of the convex portion to the thickness of the peripheral portion (the average height of the convex portion / the thickness of the peripheral portion) is, for example, preferably 0.5 or more, more preferably 0.7 or more, Preferably it is 0.8 or more, Especially preferably, it is 0.9 or more. The maximum value of the ratio (average height of convex portions / thickness of peripheral edge portion) may be preferably 1.

  The ratio of the thickness of the peripheral part to the volume average particle diameter of the resin particles (peripheral part thickness / volume average particle diameter) is preferably 0.001 or more, more preferably 0.005 or more, and still more preferably. 0.01 or more. The ratio (peripheral thickness / volume average particle diameter) is preferably 0.40 or less, more preferably 0.38 or less, and still more preferably 0.36 or less.

  Moreover, it is preferable that melting | fusing point of a peripheral part of a resin particle is 200 degreeC or more. Thereby, the hardness of a convex part can be improved. The melting point of the peripheral portion is more preferably 220 ° C. or higher, further preferably 240 ° C. or higher, and particularly preferably 250 ° C. or higher. Although the upper limit of melting | fusing point is not specifically limited, For example, it is 400 degreeC. The melting point of the peripheral edge can be measured as the temperature at which the peripheral edge is deformed by heating. Further, from the viewpoint of increasing the melting point of the peripheral portion, it is preferable that the melting points of all the components constituting the peripheral portion are 200 ° C. or higher. For example, when the peripheral portion is composed of a plurality of polymers, the melting points of all the polymers are preferably 200 ° C. or higher, more preferably 220 ° C. or higher, further preferably 240 ° C. or higher, more preferably 250. It is above ℃. The melting point is preferably 400 ° C. or lower, for example.

  Moreover, it is preferable that the said resin particle has a core-shell structure comprised with a core and a shell, Comprising: A core contains a spherical part and a shell contains the peripheral part which has a convex part. In particular, it is desirable that the peripheral portion having the convex portion is formed only by the shell, and in such a resin particle, the spherical portion is configured by only the core, and the peripheral portion having the convex portion is configured by only the shell, A spherical part is comprised by a part of core and shell, and the peripheral part which has a convex part is comprised only by a shell.

  Furthermore, in the present invention, resin particles having different convex portions (height, bottom diameter, constituent component, number density, etc.) may be mixed and used as base particles.

The resin particles preferably have a volume average particle diameter of 1 μm or more and 50 μm or less. More preferably, they are 1.5 micrometers or more and 40 micrometers or less, More preferably, they are 2 micrometers or more and 35 micrometers or less, Most preferably, they are 2.5 micrometers or more and 30 micrometers or less. Further, the coefficient of variation (CV value) of the particle diameter of the resin particles is preferably 10.0% or less, more preferably 8.0% or less, still more preferably 5.0% or less, and even more preferably 4.5% or less. Particularly preferably, it is 4.0% or less. The coefficient of variation of the particle diameter is a value calculated according to the following formula.
Variation coefficient of particle diameter (%) = 100 × (standard deviation of particle diameter / volume average particle diameter)
The volume average particle diameter of the particles and the coefficient of variation of the particle diameter can be measured by a precision particle size distribution measuring apparatus using the Coulter principle (for example, trade name “Coulter Multisizer III type”, manufactured by Beckman Coulter, Inc.) Specifically, it can be measured by the method described later in Examples.

  The transmission electron microscope used for observing the cross section of the resin particle is to detect the transmitted and scattered light by irradiating the sample with an electron beam. Among these, a bright field signal (scattering angle is 0). In the case of detecting a transmission signal in a range that includes the light, the difference in density inside the sample can be expressed by the difference in light and dark, and the dark field signal (scattering angle does not include 0 (larger than the bright field signal) scattering angle. When the transmission signal of the range is detected, the difference in the atomic weight of the contained element can be expressed by the difference in brightness. In the present invention, transmission electron microscopy that detects dark field signals is preferred. When a dark field signal is detected, a difference in brightness occurs due to a difference between the atomic weight of an element included in a specific region and the atomic weight of an element included in the surrounding region, and a boundary line can be observed. In the transmission electron micrograph of the present invention, the larger the atomic weight of the element, the lower the brightness, and the darker the region containing relatively high atomic weight elements such as silicon, phosphorus and sulfur. A region containing only an element having a relatively low atomic weight, such as hydrogen, carbon, and oxygen, is shown brighter. Needless to say, the larger the atomic weight, the higher the brightness can be displayed, and it is only necessary to observe the boundary line derived from the difference in the atomic weight of the element. A similar cross-sectional image can be obtained by using a scanning transmission electron microscope instead of the transmission electron microscope.

The resin particles are preferably formed of a vinyl polymer and / or a polysiloxane component, and more preferably contain a vinyl polymer and a polysiloxane component.
The spherical portion of the resin particle preferably contains at least a vinyl polymer, and more preferably contains a vinyl polymer and a polysiloxane component. The peripheral portion preferably includes at least a polysiloxane component, and more preferably includes a vinyl polymer and a polysiloxane component. Moreover, the composition may be the same or different between the spherical portion and the peripheral portion, and more preferably the same composition.
Similarly, the core part preferably contains at least a vinyl polymer, and more preferably contains a vinyl polymer and a polysiloxane component. The shell part preferably contains at least a polysiloxane component, and more preferably contains a vinyl polymer and a polysiloxane component. In addition, the composition may be the same or different between the core part and the shell part, and the same composition is more preferable. Here, the composition of the spherical portion, the peripheral portion, and the like is expressed by the type and mass ratio of each monomer that forms the spherical portion, the peripheral portion, and the like.

  In the present invention, the vinyl polymer means a polymer having a vinyl polymer skeleton and can be formed by polymerizing (preferably radical polymerization) a vinyl monomer (a monomer containing a vinyl group). . In the present invention, the “vinyl group” includes not only a carbon-carbon double bond (ethenyl group) but also a (meth) acryloxy group, an allyl group, an isopropenyl group, a vinylphenyl group, an isopropenylphenyl group, A substituent composed of a functional group and a polymerizable carbon-carbon double bond is also included. A polysiloxane component (also referred to as a polysiloxane skeleton) means a component having a siloxane bond (Si—O—Si) and can be formed by polymerizing a silane monomer. As the polysiloxane component, a polysiloxane component formed using a silane crosslinkable monomer (preferably a silane crosslinkable monomer of the third form described later, more preferably a silane monomer having a vinyl group). Is preferred.

  Hereinafter, first, general monomer components as raw materials for forming resin particles will be described.

The vinyl monomer forming the vinyl polymer is classified into a vinyl crosslinkable monomer and a vinyl non-crosslinkable monomer.
The vinyl crosslinkable monomer has a vinyl group and can form a crosslinked structure, and specifically, a monomer having two or more vinyl groups in one molecule (monomer ( 1)), or a monomer having one vinyl group and a binding functional group other than a vinyl group (carboxyl group, protic hydrogen-containing group such as hydroxy group, terminal functional group such as alkoxy group, etc.) in one molecule Body (monomer (2)). However, in order to form a crosslinked structure with the monomer (2), it is necessary to have a counterpart monomer capable of reacting (binding) with a binding functional group other than the vinyl group of the monomer (2). When the other monomer is not present, it is classified as a vinyl non-crosslinkable monomer.

Examples of the monomer (1) (monomer having two or more vinyl groups in one molecule) among the vinyl crosslinkable monomers include, for example, allyl (meth) such as allyl (meth) acrylate. 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-nonane Diol 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, tri Ethylene glycol di (meth) acrylate, decaethylene glycol di (me ) Acrylate, pentadecaethylene 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. Di (meth) acrylates such as trimethylolpropane tri (meth) acrylate; tetra (meth) acrylates such as pentaerythritol tetra (meth) acrylate; dipentaerythritol hexa (meth) Hexa (meth) acrylates such as acrylates; aromatic hydrocarbon cross-linking agents such as divinylbenzene, divinylnaphthalene, and derivatives thereof (preferably stears such as divinylbenzene) Emission-type polyfunctional monomer); N, N-divinyl aniline, divinyl ether, divinyl sulfide, hetero atom-containing crosslinking agents such as divinyl sulfonic acid; and the like. Among these, (meth) acrylates (polyfunctional (meth) acrylate) having two or more (meth) acryloyl groups in one molecule and aromatic hydrocarbon crosslinking agents (especially styrene polyfunctional monomers) are included. preferable.
Among the (meth) acrylates having two or more (meth) acryloyl groups in one molecule, (meth) acrylates having two (meth) acryloyl groups in one molecule are particularly preferable. A (meth) acrylate having 3 or more (meth) acryloyl groups in one molecule is preferable, and among them, an acrylate having 3 or more acryloyl groups in one molecule is 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.

  Among the vinyl crosslinkable monomers, the monomer (2) (monomer having one vinyl group and a binding functional group other than vinyl group in one molecule) is, for example, (meth) acrylic Monomers having a carboxy group such as acid; hydroxy group-containing (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, p- Monomers having a hydroxy group such as hydroxy group-containing styrenes such as hydroxystyrene; containing alkoxy groups such as 2-methoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate and 2-butoxyethyl (meth) acrylate (Meth) acrylates, having alkoxy groups such as alkoxystyrenes such as p-methoxystyrene Mer; and the like. A monomer (2) may be used independently and may use 2 or more types together.

  As the vinyl non-crosslinkable monomer, a monomer having one vinyl group in one molecule (monomer (3)), or the monomer in the case where there is no counterpart monomer ( 2) (monomer having one vinyl group and a binding functional group other than vinyl group in one molecule).

  Among the vinyl non-crosslinkable monomers, the monomer (3) (a monomer having one vinyl group in one molecule) includes a (meth) acrylate monofunctional monomer and a styrene monofunctional monomer. Is included. Examples of the (meth) acrylate monofunctional monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, and 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, cyclo Cycloalkyl (meth) acrylates such as ndecyl (meth) acrylate, cyclododecyl (meth) acrylate, isobornyl (meth) acrylate, 4-t-butylcyclohexyl (meth) acrylate; phenyl (meth) acrylate, benzyl (meth) acrylate And aromatic ring-containing (meth) acrylates such as tolyl (meth) acrylate and phenethyl (meth) acrylate, and alkyl (meth) acrylates such as methyl (meth) acrylate are preferred. Styrene monofunctional monomers include styrene; alkyl styrenes such as o-methyl styrene, m-methyl styrene, p-methyl styrene, α-methyl styrene, pt-butyl styrene, o-chlorostyrene, m-chloro. Examples include halogen group-containing styrenes such as styrene and p-chlorostyrene, and styrene is preferred. A monomer (3) may be used independently and may use 2 or more types together.

  As the vinyl monomer, an embodiment containing at least the vinyl crosslinkable monomer (1) is preferable. Among them, the vinyl crosslinkable monomer (1) and the vinyl non-crosslinkable monomer (3) are included. An embodiment (in particular, a copolymer of the monomer (1) and the monomer (3)) is preferable.

  The resin particles preferably contain 20% by mass or more of the vinyl polymer in 100% by mass of the resin particles, more preferably 30% by mass or more, still more preferably 50% by mass or more, still more preferably 60% by mass or more, particularly Preferably it contains 70 mass% or more. The upper limit of the content ratio of the vinyl polymer is 100% by mass.

  The polysiloxane component can be formed by using a silane monomer, which is divided into a silane crosslinkable monomer and a silane non-crosslinkable monomer. When a silane crosslinkable monomer is used as the silane monomer, a crosslinked structure can be formed. The cross-linked structure formed by the silane cross-linkable monomer includes one that cross-links the vinyl polymer skeleton and the vinyl polymer skeleton (first form); one that cross-links the polysiloxane skeleton and polysiloxane skeleton (first A second form); a substance that cross-links a vinyl polymer skeleton and a polysiloxane skeleton (third form).

Examples of the silane crosslinkable monomer capable of forming the first form (crosslinking between vinyl polymers) include silane compounds having two or more vinyl groups such as dimethyldivinylsilane, methyltrivinylsilane, and tetravinylsilane. It is done.
Examples of the silane crosslinkable monomer that can form the second form (crosslink between polysiloxanes) include tetrafunctional silane monomers such as tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, and tetrabutoxysilane. A trifunctional silane monomer such as methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, and ethyltriethoxysilane;
Examples of silane crosslinkable monomers that can form the third form (crosslinking between vinyl polymer and polysiloxane) include, for example, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acrylonitrile. (Meth) acryloyl groups such as loxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-acryloxypropyltriethoxysilane, 3-methacryloxyethoxypropyltrimethoxysilane Di- or trialkoxysilanes having a vinyl group (ethenyl group) such as vinyltrimethoxysilane, vinyltriethoxysilane, p-styryltrimethoxysilane; 3-glycidoxypropyltrimeth Di- or trialkoxysilanes having an epoxy group such as silane, 3-glycidoxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane; 3-aminopropyltrimethoxysilane, 3-aminopropyl And di- or trialkoxysilanes having an amino group such as triethoxysilane. These silane crosslinkable monomers may be used alone or in combination of two or more.

  Examples of the silane non-crosslinkable monomer include bifunctional silane monomers such as dialkyl silane such as dimethyldimethoxysilane and dimethyldiethoxysilane; monofunctional such as trialkylsilane such as trimethylmethoxysilane and trimethylethoxysilane. Silane monomer and the like. 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 vinyl group capable of radical polymerization (for example, a vinyl group such as a carbon-carbon double bond or a (meth) acryloyl group). That is, the polysiloxane skeleton is a silane crosslinkable monomer (preferably having a vinyl group, more preferably vinyl, which can form at least the third form (crosslinking between vinyl polymer and polysiloxane) as a constituent component. Formed by hydrolysis and condensation of a group (ethenyl group) or (meth) acryloyl group, more preferably 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, vinyltrimethoxysilane) A polysiloxane skeleton is preferable.
When the polysiloxane component is introduced into the resin particles, the amount of vinyl monomer used is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass with respect to 100 parts by mass of the silane monomer. It is not less than 5000 parts by mass, preferably not more than 4000 parts by mass, more preferably not more than 3000 parts by mass.

  The monomer component forming the resin particles preferably contains a crosslinkable monomer such as a vinyl crosslinkable monomer or a silane crosslinkable monomer. At this time, the ratio of the crosslinkable monomer (total of the vinyl crosslinkable monomer and the silane crosslinkable monomer) to the total monomers forming the vinyl polymer particles is excellent in elastic deformation, restoring force, and the like. From the viewpoint, it is preferably 1% by mass or more, more preferably 2% by mass or more, and further preferably 5% by mass or more. In the resin particles of the present invention, if the ratio of the crosslinkable monomer is within the above range, the restoring force can be improved while maintaining excellent elastic deformation characteristics. The upper limit of the ratio of the crosslinkable monomer is not particularly limited, but depending on the type of the crosslinkable monomer used, if the ratio of the crosslinkable monomer is too large, it may become too hard to be elastically deformed. . Therefore, the proportion of the crosslinkable monomer is preferably 97% by mass or less, more preferably 95% by mass or less, still more preferably 93% by mass or less, still more preferably 90% by mass or less, and particularly preferably 85% by mass. % Or less.

  The monomer component forming the resin particles may contain other components to the extent that the properties of the vinyl polymer and / or polysiloxane component are not impaired. In this case, the resin particles preferably contain 85% by mass or more of the vinyl polymer and / or polysiloxane component, more preferably 95% by mass or more, and still more preferably 98% by mass or more.

Such resin particles are, for example,
Step (a): A step of polymerizing a core monomer composition containing a vinyl monomer and / or a silane monomer as a polymerization component to form core particles,
Step (b): A step of obtaining a resin particle 1 by coating a surface of the core particle with a silane monomer composition containing a silane monomer as a polymerization component to form a shell,
It can manufacture with the manufacturing method containing.
The manufacturing method further includes:
Step (c): The resin particles 1 obtained in the step (b) are absorbed with a vinyl monomer composition for shell containing a vinyl monomer as a polymerization component, and then polymerized to obtain resin particles 2. It is preferable to include a process.

Step (a): Core particle forming step In the step (a), a core of resin particles can be produced by polymerizing a monomer composition for core containing the monomer as a polymerization component. The mechanical properties of the resin particles can be adjusted by the monomer used in the core monomer composition. The “monomer composition” means a composition composed only of a monomer, but when polymerizing the monomer composition for the core, usually a catalyst component such as a polymerization initiator is added. It is carried out in the state of coexisting with the composition.

  The core monomer composition comprises a vinyl monomer selected from the above monomers (hereinafter referred to as “core vinyl monomer”) and / or a silane monomer (hereinafter referred to as “core silane monomer”). It is preferable to include at least a vinyl monomer for the core. As the vinyl monomer for the core, among the vinyl monomers exemplified above, a monomer having two or more vinyl groups (1), a monomer having a vinyl group and other functional groups (2 ) And a monomer (3) having one vinyl group. A vinyl monomer may be used individually by 1 type, and may use 2 or more types, However, From a viewpoint of adjusting a mechanical property, it is preferable to use 2 or more types.

  As the monomer (1) having two or more vinyl groups, di (meth) acrylates and aromatic hydrocarbon crosslinking agents are preferable, and as the monomer (3) having one vinyl group, , Alkyl (meth) acrylates, cycloalkyl methacrylates, and styrene monofunctional monomers are preferred.

  The core monomer composition preferably includes a monomer (2) containing a vinyl group and other functional groups as the vinyl monomer for the core. Among the monomers (2), It is preferable to include a monomer having a hydrophilic group such as a carboxy group, a hydroxy group, an amino group, or a thiol group and a vinyl group. Thereby, the adjustment of the solubility parameter mentioned later becomes easy and it becomes easier to form a convex part.

  When the core monomer composition contains the core silane monomer, the ratio of the core vinyl monomer is 10% in the total of 100% by mass of the core vinyl monomer and the core silane monomer. It is preferably at least 20% by mass, more preferably at least 20% by mass, even more preferably at least 30% by mass, even more preferably at least 60% by mass, even more preferably at least 70% by mass, particularly preferably at least 80% by mass. It is. The upper limit is 100% by mass. When the core monomer composition includes the core silane monomer, the content of the core vinyl monomer is 0.3 parts by mass or more with respect to 1 part by mass of the core silane monomer. Preferably, it is 0.5 parts by mass or more, more preferably 2 parts by mass or more, still more preferably 3 parts by mass or more, and even more preferably 4 parts by mass or more. Moreover, it is preferable that it is 50 mass parts or less with respect to 1 mass part of silane monomers for cores, More preferably, it is 40 mass parts or less, More preferably, it is 30 mass parts or less.

Further, the ratio of the core vinyl monomer is preferably less than 60% by mass, more preferably 55% by mass or less, out of the total of 100% by mass of the core vinyl monomer and the core silane monomer. Yes, preferably 10% by mass or more, more preferably 20% by mass or more. Furthermore, the amount of the vinyl monomer for the core is preferably less than 2 parts by mass, more preferably 1.5 parts by mass or less, and still more preferably 1. with respect to 1 part by mass of the silane monomer for the core. 2 parts by mass or less, preferably 0.3 parts by mass or more, and more preferably 0.5 parts by mass or more.
When the ratio of the vinyl monomer for the core is within this range, it is particularly easy to obtain core particles having a small particle size.

  Moreover, as a silane monomer for cores, a silane crosslinkable monomer can be preferably used, and a silane crosslinkable monomer (third form) capable of forming an organic polymer skeleton and a polysiloxane skeleton is used. More preferably, it can be used.

The core monomer composition preferably has a solubility parameter of 8 (cal / cm ³ ) ^1/2 or more, and preferably 11 (cal / cm ³ ) ^1/2 or less. The solubility parameter of the core monomer composition is more preferably 8.5 (cal / cm ³ ) ^1/2 or more, further preferably 8.9 (cal / cm ³ ) ^1/2 or more, and particularly preferably 9 .1 (cal / cm ³ ) ^1/2 or more. The solubility parameter of the core monomer composition is more preferably 10.5 (cal / cm ³ ) ^1/2 or less, and even more preferably 10 (cal / cm ³ ) ^1/2 or less. The higher the solubility parameter, the higher the hydrophilicity of the core monomer composition, and the lower the solubility parameter, the higher the hydrophobicity of the core monomer composition.

  In the present invention, the solubility parameter represents the solubility parameter obtained by the Fedors method. By using the Fedors method, the solubility parameter of the monomer can be directly calculated. Moreover, the solubility parameter of the monomer composition containing a plurality of monomers is calculated for each monomer contained in the monomer composition by calculating the product of the solubility parameter and the mass ratio in the composition, It can be calculated by summing the obtained products. For details of the Fedors method, see Polymer Engineering and Science, 1974, vol. 14, p. 147-154.

In the step (a), as a method of polymerizing the core monomer composition, (i) a core vinyl monomer and / or a silane monomer are conventionally known aqueous suspension polymerization, dispersion polymerization, emulsification. Method of polymerizing by polymerization; (ii) A method of polymerizing (radical polymerization) the vinyl group-containing polysiloxane and the core vinyl monomer after obtaining the vinyl group-containing polysiloxane using the core silane monomer (Iii) a so-called seed polymerization method in which the seed particles absorb the vinyl monomer for the core and polymerize (preferably radical polymerization);
In any of the methods (i) to (iii), when the core monomer composition is polymerized, a catalyst necessary for the polymerization reaction such as a polymerization initiator is mixed with the core monomer composition. The polymerization initiator is preferably uniformly dispersed or dissolved in the composition. Moreover, in manufacturing method (i)-(iii), you may use surfactant, The usage-amount is 0.1-5 mass parts with respect to a total of 100 mass parts of monomer compositions for cores. It is preferable that it exists in the range. The surfactant used in the step (a) can be removed by washing the obtained core particles with an organic solvent such as ion-exchanged water or methanol.

  From the viewpoint of uniforming the particle diameter of the core particles, the production methods (ii) and (iii) are preferred, and the production method (i) is preferred from the viewpoint of being industrially advantageous. The method for forming the core particles can be appropriately selected depending on the intended application.

In the said manufacturing method (i), as said vinyl monomer for cores, the said vinyl monomer can be especially used without a restriction | limiting. Moreover, as a silane monomer for cores, a silane crosslinkable monomer is preferable, the silane crosslinkable monomer having two or more vinyl groups (first form), a di- or trialkoxy having a vinyl group. A silane crosslinkable monomer having a vinyl group such as silane (third form) is more preferred. As an example of the production method (i), an aqueous suspension polymerization is taken as an example. A composition obtained by mixing a core monomer composition with a (radical) polymerization initiator is suspended in an aqueous medium (for example, water), The core particles are obtained by heating (usually 50 to 100 ° C.) while stirring.
In the production method (ii), a core particle into which a polysiloxane skeleton is introduced can be obtained by using a silane crosslinkable monomer capable of forming at least the third form as a core silane monomer. .

Moreover, in the said manufacturing method (iii), it is preferable as a seed particle used for manufacture of a core particle to use the polystyrene particle | grains and polysiloxane particle | grains with a non-crosslinked or low crosslinking degree. When polysiloxane particles are used as seed particles, a polysiloxane skeleton is introduced into the vinyl polymer.
Furthermore, in the said manufacturing method (iii), the polysiloxane particle as said seed particle is a composition containing the silane crosslinkable monomer which can form said 3rd form (crosslinking between a vinyl polymer and polysiloxane). , (Co) hydrolytic condensation is preferable, and vinyl group-containing polysiloxane particles are particularly preferable. When the polysiloxane particle has a vinyl group, in the obtained core particle, the vinyl polymer and the polysiloxane skeleton are bonded via the silicon atom constituting the polysiloxane, so that the elastic property and the restoring force are excellent. Such a vinyl group-containing polysiloxane particle as the core particle has, for example, a silane crosslinkable monomer (preferably having a vinyl group) capable of forming the third form (crosslinking between vinyl polymer and polysiloxane). It can be produced by (co) hydrolytic condensation of a silane monomer (which may be a mixture) containing a di- or trialkoxysilane.

In the production method (iii), the core monomer composition means a combination of seed particles and a core vinyl monomer to be absorbed by the seed particles. The solubility parameter of the core monomer composition is calculated by adding the product of the seed particle mass ratio and the solubility parameter and the product of the mass ratio and solubility parameter of each of the core vinyl monomers. can do. The solubility parameter of the seed particles is the same as the solubility parameter of the monomer composition forming the seed particles.
In the production method (iii), specifically, for example, the core particles are mixed with an emulsion of the core vinyl monomer while stirring in a state where the seed particles are dispersed in a solvent. The monomer can be absorbed, and the core can be produced by further heating to advance the polymerization reaction. As the solvent for dispersing the seed particles, water or an organic solvent containing water as a main component is preferable. Further, as the emulsion containing the core vinyl monomer, an emulsion obtained by emulsifying a mixture of the core vinyl monomer and the polymerization initiator in water is preferably used. The heating temperature is preferably in the range of 50 to 100 ° C.

Step (b): Silane monomer coating step In the step (b), the surface of the core particles is coated with a silane monomer composition containing a silane monomer as a polymerization component to form a shell, and the present invention. The resin particles 1 can be obtained. Thereby, a convex part can be formed appropriately and the resin particle of this invention can be obtained efficiently.
In particular, according to the above method, the predetermined convex portion can be formed even when the melting point of the resin forming the convex portion is 200 ° C. or higher.

As the silane monomer used in the silane monomer composition in the step (b) (hereinafter referred to as “shell silane monomer”), a silane crosslinkable monomer can be preferably used. As a result, the melting point of the convex portion can be increased, and in the resulting shell, the vinyl polymer and the polysiloxane skeleton are bonded via the silicon atoms constituting the polysiloxane, so that the elastic properties and the restoring force are excellent. It becomes. The silane monomer for shell is more preferably a silane crosslinkable monomer capable of forming the third form (crosslinking between vinyl polymer and polysiloxane), and more preferably a silane crosslinkable monomer having a vinyl group. A dimer or trialkoxysilane having a vinyl group is particularly preferred. As the silane monomer for shell, one kind may be used alone, or two or more kinds may be used in combination.
Moreover, when not performing the process (c) mentioned later, as a silane monomer for shells, using the silane crosslinkable monomer which can form the 3rd form (crosslinking between a vinyl polymer and polysiloxane) is used. preferable.

Further, the solubility parameter of the silane monomer composition for shell is preferably 6 (cal / cm ³ ) ^1/2 or more, and preferably 10 (cal / cm ³ ) ^1/2 or less. The solubility parameter of the silane monomer composition for shell is more preferably 6.5 (cal / cm ³ ) ^1/2 or more, and further preferably 7 (cal / cm ³ ) ^1/2 or more. The solubility parameter of the silane monomer composition for shell is more preferably 9.5 (cal / cm ³ ) ^1/2 or less, and further preferably 9 (cal / cm ³ ) ^1/2 or less. The larger the solubility parameter, the higher the hydrophilicity of the shell silane monomer composition, and the lower the solubility parameter, the higher the hydrophobicity of the shell silane monomer composition.

It is preferable that the shell silane monomer is different from the core monomer composition in terms of hydrophilicity / hydrophobicity in order to easily form a convex portion. From such a viewpoint, the absolute value of the difference in solubility parameter between the core monomer composition and the shell silane monomer composition is preferably 0.35 (cal / cm ³ ) ^1/2 or more. . The larger the absolute value of the difference in solubility parameter, the greater the difference in hydrophilicity / hydrophobicity and the larger the contact angle of the convex portion. Therefore, the absolute value of the difference in solubility parameter between the core monomer composition and the shell silane monomer composition is more preferably 0.4 (cal / cm ³ ) ^1/2 or more, Preferably, it is 0.45 (cal / cm ³ ) ^1/2 or more. Further, if the difference in solubility parameter becomes too large, the core and the shell may be separated due to the difference in hydrophilicity / hydrophobicity. Therefore, the absolute value of the difference in solubility parameter between the core monomer composition and the shell silane monomer composition is preferably, for example, 10 (cal / cm ³ ) ^1/2 or less, more preferably 5 (Cal / cm ³ ) ^1/2 or less, more preferably 3 (cal / cm ³ ) ^1/2 or less.

  In the step (b), the mass ratio of the core monomer composition to the shell silane monomer composition (shell silane monomer composition / core monomer composition) is 0.025 or more. 1 or less. As the mass ratio (silane monomer composition for shell / monomer composition for core) is larger, the contact angle and size (height, bottom diameter) of the convex portion are likely to increase. The mass ratio (silane monomer composition for shell / monomer composition for core) is more preferably 0.03 or more, further preferably 0.04 or more, more preferably 0.5 or less, Preferably it is 0.1 or less. When the shell silane monomer contains two or more monomers, the solubility parameter of the shell silane monomer is calculated as the sum of the product of the solubility parameter of each monomer and its mass ratio. it can.

As a method for forming the shell by coating the surface of the core particle with the shell silane monomer composition, a method of (co) hydrolytic condensation of the shell silane monomer composition on the surface of the core particle is preferable. .
Specifically, a shell is formed on the surface of the core particle by adding and mixing the silane monomer composition for the shell while stirring a liquid in which the core particle is dispersed in a solvent containing water and a hydrolysis catalyst. Resin particles 1 are obtained. As the solvent for dispersing the core particles, water or an organic solvent excellent in water solubility is preferable, and water, methanol, ethanol or 2-propanol is more preferable. As the solvent for dispersing the core particles, one kind may be used alone, or two or more kinds may be mixed and used. The reaction temperature is preferably in the range of 0 to 100 ° C, more preferably 10 to 50 ° C. Moreover, the resin particle 1 in which the shell was formed on the surface of the core particle can also be obtained by adding and mixing the silane monomer composition for shell to the reaction solution in which the core particle is dispersed after the polymerization of the core particle. .

  In the case where step (c) described later is not performed, when a silane crosslinkable monomer having a vinyl group is used as the shell silane monomer, the polymerization reaction of the vinyl group is carried out after the hydrolysis condensation reaction. Is preferably performed. Specifically, the reaction liquid after the hydrolysis condensation reaction may be heated (preferably 50 to 100 ° C.) in the presence of a polymerization initiator. Thereby, resin particles 1 having a polysiloxane component (polysiloxane skeleton) and a vinyl polymer (skeleton) and having a shell layer having a cross-link between the vinyl polymer and the polysiloxane are obtained.

Step (c): Vinyl monomer absorption step In step (c), the resin particle 1 obtained in step (b) is made to absorb a vinyl monomer composition for a shell containing a vinyl monomer as a polymerization component. After polymerization, the resin particles 2 of the present invention can be obtained.

  The vinyl monomer used for the shell vinyl monomer composition (hereinafter referred to as “shell vinyl monomer”) can be selected from the vinyl monomers exemplified above. Specifically, as a vinyl monomer for shell, a monomer having two or more vinyl groups (1), a monomer having one vinyl group and a binding functional group other than vinyl groups (2 ) And a monomer (3) having one vinyl group. As the vinyl monomer for shell, one kind may be used alone, or two or more kinds may be used, but it is preferable to use two or more kinds from the viewpoint of adjusting mechanical properties. As the monomer (1) having two or more vinyl groups, di (meth) acrylates and aromatic hydrocarbon crosslinking agents are preferable. As the monomer (2) having one vinyl group and a binding functional group other than the vinyl group, hydroxy group-containing (meth) acrylates are preferable. Moreover, as a monomer (3) which has one vinyl group, alkyl (meth) acrylates and a styrene monofunctional monomer are preferable.

  The vinyl monomer composition for shell may contain a monomer other than the vinyl monomer for shell, but it is preferable that the vinyl monomer for shell is a main component. In 100% by mass of the vinyl monomer composition for use, the mass ratio of the vinyl monomer for shell is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 98% by mass or more. Especially preferably, it is 100 mass%.

  In the vinyl monomer composition for shell, the proportion of the vinyl crosslinkable monomer is preferably 10% by mass or more, and more preferably 15% by mass. As the proportion of the vinyl crosslinkable monomer increases, the contact angle of the convex portion tends to increase. The upper limit of the ratio of the vinyl crosslinkable monomer is 100% by mass.

The solubility parameter of the vinyl monomer composition for shell is preferably 8 (cal / cm ³ ) ^1/2 or more, and preferably 11 (cal / cm ³ ) ^1/2 or less. The solubility parameter of the vinyl monomer composition for shell is more preferably 8.5 (cal / cm ³ ) ^1/2 or more, further preferably 8.9 (cal / cm ³ ) ^1/2 or more, particularly preferably 9.1 (cal / cm ³ ) ^1/2 or more. Further, the solubility parameter of the vinyl monomer composition for shells is more preferably 10.5 (cal / cm ³ ) ^1/2 or less, and further preferably 10 (cal / cm ³ ) ^1/2 or less. The higher the solubility parameter, the higher the hydrophilicity of the vinyl monomer composition for shells, and the lower the solubility parameter, the higher the hydrophobicity of the vinyl monomer composition for shells.

The absolute value of the difference between the solubility parameter of the shell vinyl monomer composition and the solubility parameter of the core monomer composition is preferably 0.1 (cal / cm ³ ) ^1/2 or more. As the absolute value of the solubility parameter difference increases, the contact angle of the convex portion tends to increase.
The absolute value of the difference in solubility parameter is preferably 1.0 (cal / cm ³ ) ^1/2 or less, and more preferably 0.9 (cal / cm ³ ) ^1/2 or less. When the absolute value of the difference between the solubility parameter of the shell vinyl monomer composition and the solubility parameter of the core monomer composition is within this range, the shape of the convex portion can be easily controlled.

  In the step (b), the mass ratio of the vinyl monomer composition for shell and the silane monomer for shell (vinyl monomer composition for shell / silane monomer for shell) is 0.05 or more, Preferably it is less than 14. The larger the mass ratio (the vinyl monomer composition for shell / the silane monomer for shell) is, the larger the size (height, bottom diameter) of the convex portion is, and the number of convex portions per resin particle Or the number density is small. More preferably, it is 0.1 or more, More preferably, it is 0.15 or more, More preferably, it is 12 or less, More preferably, it is 10 or less. When the mass ratio of the shell vinyl monomer composition to the shell silane monomer (shell vinyl monomer composition / shell silane monomer) is within this range, the contact angle is adjusted to 30 ° or more. Easy to do.

The polymerization method after absorbing the shell vinyl monomer is preferably radical polymerization.
As a specific example of the step (c), for example, the vinyl monomer for shell is absorbed by mixing the emulsion of the vinyl monomer composition for shell while stirring with the resin particles 1 dispersed in a solvent. Then, the resin particles 2 can be produced by heating to advance the polymerization reaction. A preferable solvent in which the resin particles 1 are dispersed includes a solvent in which the core particles in the step (b) are dispersed. As the emulsion containing the shell vinyl monomer composition, an emulsion obtained by emulsifying a mixture of the shell vinyl monomer composition and the polymerization initiator in water is preferably used. When emulsifying, a surfactant (preferably an anionic surfactant) may be used, and the amount used is, for example, 1 to 10 parts by mass with respect to 100 parts by mass of the vinyl monomer for core. It is preferably 1 to 5 parts by mass. Further, a dispersion aid may be used in combination. It is preferable that the usage-amount of a dispersion | distribution adjuvant is 0.1-10 mass parts with respect to 100 mass parts of surfactant. The heating temperature is preferably in the range of 50 to 100 ° C.

Further, the obtained fine particles may be classified as necessary and dried or fired. Although heating temperature is not specifically limited, Usually, it is preferable that it is the range of 50 to 350 degreeC.
The resin particles used for the base particles can be manufactured by the above-described manufacturing method.

(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 particles (resin particles).

  Examples of the metal constituting the conductive metal layer include, for example, gold, silver, copper, platinum, iron, lead, aluminum, chromium, palladium, nickel, rhodium, ruthenium, antimony, bismuth, germanium, tin, cobalt, and indium. And metals such as nickel-phosphorus and nickel-boron, 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, Au, Bi, Al, Mn, Mg, P, B Alloy with one metal element, preferably Ag-Ni, Ag-Sn, Ag-Z ); 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.) Etc.) are preferred. 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. Are preferred.

  The thickness of the conductive metal layer is preferably 0.01 μm or more, more preferably 0.03 μm or more, further preferably 0.05 μm or more, preferably 0.3 μm or less, more preferably 0.25 μm or less, More preferably, it is 0.2 micrometer or less, More preferably, it is 0.15 micrometer or less. In the present invention in which the resin particles used as the substrate have convex portions, if the thickness of the conductive metal layer is within the above range, the convex portions of the resin particles are formed on the surface even after the conductive fine particles are formed. Convex portions corresponding to are formed, and the connection stability is improved. The thickness of the conductive metal layer can be measured, for example, by a method described later in Examples.

  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 the conductive metal layer is not formed” means that the surface of any 10,000 conductive fine particles is observed using a scanning electron microscope (magnification 1000 times). Furthermore, it means that the crack of the conductive metal layer and the exposure of the resin particle surface are not substantially visually observed.

The volume average particle diameter of the conductive fine particles of the present invention is preferably 1 μm or more, more preferably 1.1 μm or more, further preferably 1.6 μm or more, still more preferably 2.1 μm or more, and preferably 51 μm or less. More preferably, it is 50 micrometers or less, More preferably, it is 41 micrometers or less, More preferably, it is 36 micrometers or less, More preferably, it is 31 micrometers or less. If the volume average particle diameter is in this range, it can be suitably used for electrical connection of electrodes and wirings that are miniaturized and narrowed. In addition, the coefficient of variation (CV value) of the conductive fine particles is preferably 10.0% or less, more preferably 8.0% or less, still more preferably 5.0% or less, and even more preferably 4.5%. Hereinafter, it is particularly preferably 4.0% or less. The coefficient of variation of the particle diameter is a value calculated according to the following formula.
Variation coefficient of particle diameter (%) = 100 × (standard deviation of particle diameter / volume average particle diameter)
As the volume average particle diameter of the conductive fine particles, the average particle diameter based on the number of 3000 particles obtained 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, 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 with the base particle (resin particle), the base particle (resin particle) itself may be destroyed before the insulating resin layer is destroyed. Therefore, it is preferable to use an uncrosslinked or relatively low degree of crosslinking resin for the insulating resin layer.

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

  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.

(Anisotropic conductive material)
The anisotropic conductive material of the present invention includes 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. 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). Suitable applications of the anisotropic conductive material include touch panel input, LED use, and the like, and particularly suitable for touch panel mounting.

The binder resin is an insulating resin, for example, a thermoplastic resin such as an acrylic resin, an ethylene-vinyl acetate resin, a styrene-butadiene block copolymer; a curing agent such as a monomer or oligomer having a glycidyl group and isocyanate. Curable resin composition cured by reaction with curable resin; curable resin composition 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. 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 content is preferably 1% by volume or more, more preferably 2% in the total amount of the anisotropic conductive material. Volume% or more, More preferably, it is 5 volume% or more, 50 volume% or less is preferable, More preferably, it is 30 volume% or less, More preferably, it is 20 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. .

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. Of course, it is possible to implement them, and they are all included in the technical 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.
<Volume average particle diameter and coefficient of variation (CV value) of resin particles>
In the case of resin particles and core, 0.1 part of resin particles or core is mixed with polyoxyethylene alkyl ether sulfate ammonium salt (Daiichi Kogyo Seiyaku Co., Ltd. “Hitenol (registered trademark) N-08”). 20 parts of a 1% aqueous solution of 1) and dispersed for 10 minutes with ultrasonic waves are used as measurement samples. In the case of seed particles, the dispersion obtained by hydrolysis and condensation reaction is treated with polyoxyethylene alkyl ether sulfate. Using a sample diluted with a 1% aqueous solution of an ester ammonium salt (Daiichi Kogyo Seiyaku Co., Ltd. “Hitenol (registered trademark) N-08”) as a measurement sample, The particle size (μm) of 30000 particles was measured by “type”), and the volume average particle size was determined. In addition, for the resin particles and the core, the standard deviation of the particle size on the volume basis was obtained together with the volume average particle size, and the coefficient of variation (CV value) of the particle size was calculated according to the following formula.
Variation coefficient of particle diameter (%) = 100 × (standard deviation of particle diameter / volume average particle diameter)

<Structure of convex part>
The cross section of the resin particles was photographed with a scanning transmission electron microscope under the conditions of a magnification of 10,000 to 30,000 times and an acceleration voltage of 20 kV.

<Average height of protrusions, average bottom diameter>
In an SEM image obtained by photographing a resin particle at a magnification of 10,000 times or more using a scanning electron microscope (SEM), the boundary of the convex portion and the boundary of the spherical portion that exist at the peripheral portion of the resin particle intersect 2 Connect the points with line segments, make the distance between the line segment and the most convex part of the convex part the height, and the length of the line segment (distance between the two points where the boundary of the convex part and the boundary of the spherical part intersect) The bottom diameter was measured. The height and bottom surface diameter of 50 convex portions per one type of resin particles were measured and averaged to obtain the average height and average bottom surface diameter of the convex portions of the resin particles.

<Number of convex parts>
Using a scanning electron microscope (SEM), resin particles were photographed at a magnification of 3000 times or more, and the number of convex portions on the resin particles was measured. The number of convex portions of five resin particles per one type of resin particles was measured and averaged and doubled to obtain the number of convex portions per resin particle.

<Convex unevenness index between particles>
For five resin particles, the number of convex portions per particle was calculated and the standard deviation was calculated, and the convex portion variation index between particles was calculated according to the following formula.
Protrusion variation index between particles = (standard deviation of the number of protrusions per 5 particles) / (average number of protrusions per resin particle)

<Convex unevenness index on a single particle>
When the particle was viewed on the orthographic projection plane, two lines perpendicular to each other were drawn at the particle center to divide the particle into four sections. The number of protrusions was measured for each section, and the standard deviation of the number of protrusions in one particle was calculated. The number of convex portions of five resin particles was measured for one type of resin particles, the average value of standard deviations was calculated, and the projection variation index on a single particle was calculated according to the following formula.
Protrusion variation index on a single particle = (standard deviation of protrusions per resin particle) / (average number of protrusions per resin particle)

<Number density of protrusions>
Using a scanning electron micrograph taken at a magnification of 10,000 times or more, the diameter of the spherical portion or the diameter including the spherical portion and the peripheral layer was calculated using a caliper diameter calculation tool attached to the apparatus. The number of convex parts per resin particle is the surface area of the spherical part (4 × π × the square of the radius of the spherical part) or the surface area of the peripheral layer (4 × π × (the sum of the radius of the spherical part and the thickness of the peripheral layer). Divided by the square of).

<Contact angle when the convex portion is assumed to be a droplet with respect to the spherical portion>
Using a scanning transmission electron microscope, a cross section of the resin particle was photographed at a magnification of 10,000 times or more, and an angle formed by the boundary line of the convex part and the boundary line of the spherical part was defined as a contact angle. Further, the contact angle was measured for 10 or more convex portions of one type of resin particle, and the average was taken as the contact angle when the convex portion of the resin particle was assumed to be a droplet with respect to the spherical portion.

<Projection drop test>
25 parts of toluene was added to 1 part of resin particles, 250 parts of zirconia beads having a diameter of 1 mm were further added, and dispersion was performed at 200 rpm for 10 minutes using two stainless steel stirring blades. After the dispersion treatment, a metal sieve having an opening of 500 μm was passed through to remove zirconia beads, and the resin particles were taken out by filtration through a membrane filter (3.0 μm; manufactured by Advantech) and dried.
The obtained particles were observed using a scanning electron microscope (SEM), and the number of protrusions was calculated for five particles. The drop-off property of the protrusions was judged according to the following criteria from the average value of the number of protrusions per particle before and after the treatment.
When the value of (average value of the number of protrusions per particle after treatment) / (average value of the number of protrusions per particle before treatment) exceeds 0.9, “◯”, 0.9 or less Was evaluated as “×”.

<Measuring method of melting point>
The glass plate on which the particles were dispersed was placed in a heating furnace heated to a predetermined temperature, and heat-treated for 60 minutes. The particles before and after the heat treatment were observed with an SEM, and the temperature at which the shape of the contact point between the particles and the glass plate was changed was defined as the melting point of the peripheral portion.

<Number average particle diameter of conductive fine particles and 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. 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 Corporation) to 0.25 parts of the particles and ultrasonically. 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

<Electrical conductivity evaluation>
Using the conductive fine particles obtained in the examples and comparative examples, an anisotropic conductive material (anisotropic conductive paste) was prepared by the following method, and the presence or absence of indentation and the initial resistance value were evaluated by the following method. . The initial resistance value and the evaluation result of the indentation are shown in Table 5.
That is, using a rotating and rotating stirrer, 100 parts of an epoxy resin (“Stractbond (registered trademark) XN-5A” manufactured by Mitsui Chemicals, Inc.) as a binder resin was added to 2.0 parts of conductive fine particles and stirred for 10 minutes. And 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 is thermocompression bonded under pressure bonding conditions of 2 MPa and 150 ° C. At the same time, the connection structure was obtained by curing the binder resin.

  Measure the initial resistance value between the electrodes of the obtained connection structure. If the initial resistance value is less than 5Ω, it is “excellent”. If it is 5Ω or more and less than 10Ω, “good”. The case of 15Ω or more was evaluated as “impossible”.

2. Production of Resin Particles Table 1 shows the abbreviations and solubility parameters of monomers used for production of resin particles.

2-1. Preparation of core particles (Synthesis Example 1)
In a four-necked flask equipped with a condenser, thermometer, and dripping port, 1000 parts of ion-exchanged water, 3 parts of 25% aqueous ammonia, and 600 parts of methanol are placed under stirring and the monomer component for core ( 100 parts of MPTMS (manufactured by Shin-Etsu Chemical Co., Ltd., “KBM503”) is added as a core silane monomer), and MPTMS is hydrolyzed and condensed to produce polysiloxane particles (seed particles having methacryloyl groups). An emulsion of polymerizable polysiloxane particles) was prepared. Two hours after the start of the reaction, the obtained emulsion of polysiloxane particles was sampled and the particle size was measured. The volume average particle size was 6.06 μm.

  Next, 50 parts of a 20% aqueous solution of polyoxyethylene styrenated phenyl ether sulfate ammonium salt (Daiichi Kogyo Seiyaku Co., Ltd., “Hitenol (registered trademark) NF-08”) as an emulsifier was diluted with 2000 parts of ion-exchanged water. In the solution, nBMA 850 parts, MMA 850 parts, HEMA 150 parts, 16HXA 150 parts as core monomer component (core vinyl monomer), 2,2′-azobis (2,4-dimethylvaleronitrile) (Wako Pure) A solution in which 42 parts of “V-65” manufactured by Yakuhin Kogyo Co., Ltd. was dissolved was added and emulsified and dispersed to prepare an emulsified liquid containing a monomer component for core (vinyl monomer for core).

  After adding the obtained emulsion to the emulsion of polysiloxane particles and stirring for 1 hour, 840 parts of a 10% aqueous solution of polyvinyl alcohol and 2000 parts of ion-exchanged water were further added, and the reaction solution was heated to 65 ° C. under a nitrogen atmosphere. The temperature was raised to 2 hours and held for 2 hours to perform radical polymerization of the monomer component. The emulsion after radical polymerization was subjected to solid-liquid separation, and the resulting cake was washed with ion-exchanged water and methanol, and then vacuum-dried at 40 ° C. for 12 hours to obtain core particles 1. The volume average particle size, coefficient of variation (CV value), and degree of cross-linking of the core particles 1 are as shown in Table 2.

(Synthesis Examples 2-9)
By appropriately changing the amount of the silane monomer for the core, ion-exchanged water, methanol, and aqueous ammonia, polysiloxane particles (seed particles) having an average particle diameter based on volume as shown in Table 2 were prepared. Core particles 2 to 9 were obtained in the same manner as in Synthesis Example 1 except that the type and amount of the monomer were changed as shown in Table 2. The volume average particle diameter, the coefficient of variation (CV value), and the degree of crosslinking of the core particles 2 to 9 were as shown in Table 2.

(Synthesis Example 10)
Polyoxyethylene styrenated phenyl ether sulfate ammonium salt (Daiichi Kogyo Seiyaku Co., Ltd., “Hytenol (registered trademark) NF-08”) as an emulsifier in a four-necked flask equipped with a condenser, thermometer, and dropping port In a solution obtained by dissolving 50 parts of a 20% aqueous solution in 2000 parts of ion-exchanged water, 100 parts of MPTMS, 850 parts of NBMA, 850 parts of MMA, 150 parts of HEMA, 150 parts of 16 HXA, A solution of 42 parts of 2′-azobis (2,4-dimethylvaleronitrile) (manufactured by Wako Pure Chemical Industries, “V-65”) was added and suspended to prepare a suspension of monomer components. did.

  Furthermore, 840 parts of a 10% aqueous solution of polyvinyl alcohol and 6000 parts of ion-exchanged water were added, and the reaction solution was heated to 65 ° C. and held for 2 hours in a nitrogen atmosphere to perform radical polymerization of the monomer component. The suspension 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 40 ° C. for 12 hours to obtain core particles 10. Furthermore, the core particle 10 was obtained by classifying using a mesh with an opening of 17 μm and 24 μm. The particle diameter, coefficient of variation (CV value), and degree of crosslinking of the core particles 10 were as shown in Table 2. The particle size before classification was 21.81 μm, and the coefficient of variation (CV value) was 47.7%.

(Synthesis Example 11)
The core particles 11 were prepared in the same manner as in Synthesis Example 10 except that the types and amounts of the monomer components for the core were changed as shown in Table 2 and classified using meshes having openings of 8 μm and 15 μm. Obtained. Table 2 shows the particle diameter, coefficient of variation (CV value), and degree of crosslinking of the core particles 11. The particle size before classification was 12.84 μm, and the coefficient of variation (CV value) was 30.7%.

(Synthesis Example 12)
Polysiloxane particles (seed particles) were prepared by appropriately changing the amounts of the silane monomer for the core, ion exchange water, methanol, and ammonia water, and the types and amounts of the vinyl monomer for the core are shown in Table 2. A core particle 12 was obtained in the same manner as in Synthesis Example 1 except that Table 2 shows the particle size, coefficient of variation (CV value), and degree of crosslinking of the core particles 12.

(Synthesis Example 13)
In a four-necked flask equipped with a condenser, thermometer, and dripping port, 1000 parts of ion-exchanged water, 3 parts of 25% aqueous ammonia, and 600 parts of methanol are placed under stirring and the monomer component for core ( 40.7 parts of MPTMS (manufactured by Shin-Etsu Chemical Co., Ltd., “KBM503”) and 59.3 parts of VTMS (manufactured by Shin-Etsu Chemical Co., Ltd., “KBM1003”) as core silane monomers), hydrolysis and condensation of MPTMS and VTMS Reaction was performed to prepare an emulsion of polysiloxane particles (polymerizable polysiloxane particles) as seed particles having methacryloyl groups and vinyl groups. Two hours after the start of the reaction, the obtained emulsion of polysiloxane particles was sampled and the particle size was measured. The volume average particle size was 2.36 μm.
Next, 2.5 parts of a 20% aqueous solution of polyoxyethylene styrenated phenyl ether sulfate ammonium salt (Daiichi Kogyo Seiyaku Co., Ltd., “Hitenol (registered trademark) NF-08”) as an emulsifier is added with 50 parts of ion-exchanged water. In the dissolved solution, 50 parts of DVB (“DVB960” manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) as a core monomer component (core vinyl monomer) and 2,2′-azobis (2,4-dimethylvaleronitrile) ) (Manufactured by Wako Pure Chemical Industries, Ltd., “V-65”) A solution in which 1.6 parts are dissolved is added and emulsified and dispersed to obtain an emulsion A containing a core monomer component (core vinyl monomer). Prepared.
Next, 0.4 part of 20% aqueous solution of polyoxyethylene styrenated phenyl ether sulfate ammonium salt (Daiichi Kogyo Seiyaku Co., Ltd., “Hytenol (registered trademark) NF-08”) as an emulsifier is added with 15 parts of ion-exchanged water. To the dissolved solution, 15 parts of CHMA as a core monomer component (core vinyl monomer) is added and emulsified and dispersed to prepare emulsion B containing the core monomer component (core vinyl monomer). Prepared.
The obtained emulsion A was added to an emulsion of polysiloxane particles, stirred for 1 hour, and then further polyoxyethylene styrenated phenyl ether sulfate ammonium salt (Daiichi Kogyo Seiyaku Co., Ltd., “Hitenol (registered trademark) ) NF-08 ") 20% aqueous solution (8.3 parts) was added, the reaction solution was heated to 65 ° C under a nitrogen atmosphere and held for 1 hour, then Emulsion B was added, and the reaction solution was further added under a nitrogen atmosphere. Was held at 65 ° C. for 2 hours to carry out radical polymerization of the monomer component.
The emulsion after radical polymerization was subjected to solid-liquid separation, and the obtained cake was washed with ion-exchanged water and methanol, and then vacuum dried at 120 ° C. for 2 hours to obtain core particles 13. The volume average particle size, coefficient of variation (CV value), and degree of crosslinking of the core particles 13 are as shown in Table 2.

2-2. Production of resin particles (Production Example 1)
In a four-necked flask equipped with a condenser, a thermometer and a dropping port, 525 parts of methanol, 1050 parts of ion-exchanged water, 1.4 parts of 25% aqueous ammonia, 20% of polyoxyethylene styrenated phenyl ether sulfate ammonium salt After mixing 17.5 parts of aqueous solution and dispersing 70 parts of core particles 1, 7.0 parts of MPTMS was added as a monomer component for shell (shell silane monomer) and stirred for 2 hours to disperse core particles A liquid was prepared. St30.8 as a monomer component for shell (vinyl monomer for shell) was added to a solution of 0.9 part of 20% aqueous solution of polyoxyethylene styrenated phenyl ether sulfate ammonium salt dissolved in 100 parts of ion exchange water. Parts, DVB (“DVB960” manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) 4.2 parts and 2,2′-azobis (2,4-dimethylvaleronitrile) (manufactured by Wako Pure Chemical Industries, “V-65”) After adding 4 parts of the dissolved solution and emulsifying and dispersing the emulsified dispersion of the shell monomer component (shell vinyl monomer) to the core particle dispersion, the mixture is stirred for 1 hour, and then used as a dispersion aid. A solution obtained by dissolving 0.04 part of Milling 4GW (manufactured by Nippon Kayaku Co., Ltd.) in 20 parts of ion-exchanged water is added, and the reaction solution is heated to 65 ° C. and held for 2 hours under a nitrogen atmosphere. Perform radical polymerization It was. The emulsion after radical polymerization was subjected to solid-liquid separation, and the obtained cake was washed with ion-exchanged water and methanol, and then vacuum-dried at 40 ° C. for 12 hours to obtain resin particles (1).

(Production Examples 2-8, 10-13, 16, 17, 19-23)
As shown in Table 3 or Table 4, polyoxyethylene used in the emulsion of core particles, shell silane monomer, shell vinyl monomer, shell monomer component (shell vinyl monomer) In the same manner as in Production Example 1 except that a 20% aqueous solution of styrenated phenyl ether sulfate ammonium salt (described as “surfactant aqueous solution” in Tables 3 and 4) and Kayanol Milling 4 GW were used, resin particles ( 2) to (8), (10) to (13), (16), (17), and (19) to (23) were obtained. The particle diameter of the resin particles obtained in the same manner as in Production Example 22 using the particles before classification of the core particles 10 is 27.79 μm, the coefficient of variation (CV value) is 40.2%, and the surface area of the spherical portion is 1494 μm ² , the average height of the protrusions is 0.26 μm, the average base diameter of the protrusions is 0.87 μm, the contact angle of the protrusions is 57 °, the number of protrusions per resin particle is 1563 / particle, The number density of the convex portions was 1.05 number / μm ² , the convex portion variation index between particles was 2.0, the melting point was 250 ° C. or higher, and the evaluation result of the projection drop test was “◯”. The particle diameter of the resin particles obtained in the same manner as in Production Example 23 using the particles before classification of the core particles 11 is 16.65 μm, the coefficient of variation (CV value) is 31.1%, and the surface area of the spherical portion is 518 μm ² , the average height of the protrusions is 0.21 μm, the average base diameter of the protrusions is 0.45 μm, the contact angle of the protrusions is 83 °, and the number of protrusions per resin particle is 3009 particles / particle. The number density of the convex portions was 5.81 number / μm ² , the convex portion variation index between particles was 8.7, the melting point was 250 ° C. or higher, and the evaluation result of the protrusion drop test was “good”.

(Production Example 9)
In a four-necked flask equipped with a condenser, a thermometer and a dropping port, 525 parts of methanol, 1050 parts of ion-exchanged water, 1.4 parts of 25% aqueous ammonia, 20% of polyoxyethylene styrenated phenyl ether sulfate ammonium salt After mixing 17.5 parts of aqueous solution and dispersing 70 parts of core particles 3, add 14.0 parts of VTMS as a monomer component for shell (shell silane monomer), and stir for 2 hours to disperse core particles A liquid was prepared. A solution prepared by dissolving 0.4 part of 2,2′-azobis (2,4-dimethylvaleronitrile) (manufactured by Wako Pure Chemical Industries, Ltd., “V-65”) in 4 parts of methanol was added, and the reaction solution was added in a nitrogen atmosphere. The temperature was raised to 65 ° C. and held for 2 hours to perform radical polymerization of the monomer component. The emulsion after radical polymerization was subjected to solid-liquid separation, and the obtained cake was washed with ion-exchanged water and methanol, and then vacuum-dried at 40 ° C. for 12 hours to obtain resin particles (9).

(Production Examples 14, 15, 18)
The core particles shown in Tables 3 and 4 were used as the core particles, and the monomer species shown in Tables 3 and 4 were used as the silane monomers for the shells in the amounts used as shown in Tables 3 and 4. Except that, resin particles (14), (15), and (18) were obtained in the same manner as in Production Example 9.

(Production Example 24)
In a four-necked flask equipped with a cooling tube, a thermometer, and a dropping port, 80 parts of ethanol, 30 parts of ion-exchanged water, and 3.6 parts of polyvinylpyrrolidone (“PVP K-30” manufactured by Wako Pure Chemical Industries, Ltd.) After mixing and dispersing 30 parts of the core particles 2, 0.03 part of 2,2′-azobis (2-methylbutyronitrile) (manufactured by Wako Pure Chemical Industries, “V-59”), NPGDMA 0.6 The mixture was mixed with a solution of 2.4 parts of St and 2.4 parts, and the reaction solution was heated to 70 ° C. and held for 5 hours under a nitrogen atmosphere to carry out radical polymerization of the monomer components. The cake was washed with ion-exchanged water and methanol and then vacuum-dried at 40 ° C. for 12 hours to obtain resin particles (24).

(Production Example 25)
Resin particles (25) were obtained in the same manner as in Production Example 24 except that the core particles as shown in Tables 3 and 4 were used as the core particles.

(Production Example 26)
A solution obtained by adding 1000 parts of ion-exchanged water, 95 parts of StA and 5 parts of MAA to a four-necked flask equipped with a condenser, a thermometer, and a dripping port was heated to 70 ° C. in a nitrogen atmosphere, and then ammonium persulfate 0 A solution in which 8 parts and 100 parts of ion-exchanged water were mixed was added and radical polymerization of the monomer component was performed for 8 hours. The emulsion after radical polymerization was pulverized by spray drying to obtain child particles of 300 nm. 10 parts of the obtained child particles and 100 parts of the core particles (9) were combined by hybridization to obtain resin particles (26).

(Production Example 27)
In a four-necked flask equipped with a condenser, a thermometer, and a dropping port, 364 parts of methanol, 1456 parts of ion-exchanged water, 4.4 parts of 25% aqueous ammonia, 20% of polyoxyethylene styrenated phenyl ether sulfate ammonium salt After mixing 17.5 parts of aqueous solution and dispersing 70 parts of core particles 12, 14.0 parts of MPTMS is added as a monomer component for shell (shell silane monomer) and stirred for 2 hours to disperse core particles. A liquid was prepared. DVB (Nippon Steel) as a monomer component for shells (vinyl monomer for shells) was prepared by dissolving 0.2 parts of a 20% aqueous solution of polyoxyethylene styrenated phenyl ether sulfate ammonium salt with 100 parts of ion-exchanged water. 7.0 parts of “DVB960” manufactured by Sumikin Chemical Co., Ltd. and 2.1 parts of 2,2′-azobis (2,4-dimethylvaleronitrile) (“V-65” manufactured by Wako Pure Chemical Industries, Ltd.) were dissolved. After adding the solution and emulsifying and dispersing the emulsified shell monomer component (shell vinyl monomer) to the core particle dispersion, the mixture is stirred for 1 hour and then dissolved in 21.0 parts of a 10% aqueous solution of polyvinyl alcohol. The solution was added, and the reaction solution was heated to 65 ° C. and held for 2 hours under a nitrogen atmosphere, and radical polymerization of the monomer component was performed. The emulsion after radical polymerization was subjected to solid-liquid separation, and the obtained cake was washed with ion-exchanged water and methanol, and then vacuum-dried at 80 ° C. for 4 hours to obtain resin particles (27).

(Production Example 28)
As shown in Table 4, Production Example 27 except that the core particles, the shell silane monomer, and the shell vinyl monomer were used, and the drying was changed to a baking treatment at 280 ° C. for 1 hour in a nitrogen atmosphere. Similarly, resin particles (28) were obtained.

Mass ratio of the monomer composition for core and the silane monomer for shell in Production Examples 1 to 28 (silane monomer for shell / monomer composition for core), vinyl monomer for shell and shell Mass ratio of silane monomer (vinyl monomer for shell / silane monomer for shell), solubility parameter SP _{CORE of} core monomer composition, solubility parameter of silane monomer for shell and single amount for core Tables 3 and 4 show the difference from the solubility parameter of the body composition (silane monomer for shell-monomer composition for core) ΔSP.
In addition, for the obtained resin particles (1) to (28), the volume average particle diameter, the coefficient of variation (CV value), the average height of the protrusions, the average bottom diameter of the protrusions, and the ratio of the height of the protrusions to the base (Height / bottom), the ratio of the height of the protrusion to the volume average particle diameter of the resin particles (height / resin particle diameter), the product of the height of the protrusion and the bottom of the protrusion (height × bottom), between the particles Convexity variation index, convexity variation index on a single particle, number of convex portions per resin particle, number of convex portions per 1 μm ^{2 of} spherical surface area (number density), surface area of spherical portion ( The results of the spherical surface area are shown in Tables 3 and 4.

  As a result of scanning transmission electron microscope observation, the resin particles obtained in Production Examples 1 to 7, 9 to 20, 22, 23, 27, and 28 have a spherical portion and a plurality of convex portions formed on the surface thereof. The boundary line between the convex part and the spherical part has a structure in which the convex part swells to the convex part side, and the convex part is difficult to be detached. Moreover, the boundary line of the spherical part was continuous without having an inflection point regardless of whether or not the convex part was present.

(Examples 1 to 23, Comparative Examples 1 to 5)
After the resin particles used as the base material are etched with sodium hydroxide, they are sensitized by bringing them into contact with a tin dichloride solution, and then activated by immersing them in a palladium dichloride solution. Palladium nuclei were formed by the tizing-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.
With respect to the obtained conductive fine particles, the contact angles of the convex portions of the substrate particles (resin particles), the film thickness of the conductive metal layer, and the results of the conductivity evaluation were as shown in Table 5.

  In all of the conductive fine particles of Examples 1 to 23, the base particles (resin particles) had a plurality of convex portions, and were excellent in conductivity when an anisotropic conductive material was used. Moreover, it was in the tendency for it to be excellent in electroconductivity, so that the contact angle of a convex part became large in the range of 90 degrees or less. On the other hand, Comparative Examples 1 and 2 using base particles (resin particles) having no convex part, and Comparative Examples 3 and 3 in which the center of curvature of the boundary line between the peripheral part and the spherical part does not exist in the spherical part. No. 5 was inferior in conductivity because the convex portion was easily detached when an anisotropic conductive material was used.

  Since the conductive fine particles of the present invention are composed of resin particles having a plurality of convex portions on the surface and a conductive metal layer covering along the convex shape, the conductive fine particles are difficult to remove. Can be obtained regardless of the plating conditions. For this reason, it is extremely useful for anisotropic conductive materials such as anisotropic conductive films, anisotropic conductive pastes, anisotropic conductive adhesives, and anisotropic conductive inks.

DESCRIPTION OF SYMBOLS 1 Spherical part 2a Peripheral part 2b Peripheral layer 3 Convex part 4 Triangle 5 Triangular base 6a, 6b Protrusion starting point 8 Convex top part 9a Convex side tangent 9b Peripheral layer side tangent 10 Boundary line

Claims (8)

Conductive fine particles having resin particles having a plurality of convex portions on the surface and a conductive metal layer covering the surface convex portions of the resin particles along the convex shape,
The resin particles are resin particles composed of a peripheral portion having a plurality of convex portions on the surface and a spherical portion surrounded by the peripheral portion, and
When the cross section of the resin particle is observed with a transmission electron microscope, the center of curvature of the boundary line between the peripheral portion and the spherical portion exists in the spherical portion ,
The peripheral edge is a conductive fine particle formed using a silane crosslinkable monomer having a vinyl group .   The conductive fine particles according to claim 1, wherein the average contact angle of the convex portions is 30 ° or more and 90 ° or less.   The ratio of the average height of the protrusions to the volume average particle diameter of the resin particles (average height of protrusions / volume average particle diameter of resin particles) is 0.001 or more and 0.20 or less. Or Conductive fine particles according to 2.   The conductive fine particles according to any one of claims 1 to 3, wherein a coefficient of variation of the number of convex portions per one resin particle is 20% or less.   In a scanning electron microscope image of a resin particle, two straight lines perpendicular to each other are drawn at the center of the resin particle to divide the resin particle into four sections, and for each resin particle, the standard deviation of the number of convex portions per section is calculated. The conductive fine particles according to any one of claims 1 to 4, wherein the average value is 10% or less when calculated and divided by the number of convex portions per resin particle.   The conductive fine particles according to any one of claims 1 to 5, having a volume average particle diameter of 1 µm or more and 50 µm or less. The conductive fine particles according to claim 1, wherein the peripheral portion is further formed using a vinyl monomer. Anisotropic conductive material containing conductive fine particles according to any one of claims 1-7.