JP6962307B2 - Conductive particles for anisotropic conductive adhesives - Google Patents

Description

The present invention relates to conductive particles for anisotropic conductive adhesives.

The method of mounting a liquid crystal driving IC (Integrated Circuit) on a liquid crystal display glass panel can be roughly classified into two types: COG (Chip-on-Glass) mounting and COF (Chip-on-Flex) mounting. In COG mounting, the liquid crystal drive IC is directly bonded onto the glass panel using an anisotropic conductive adhesive containing conductive particles. On the other hand, in COF mounting, a liquid crystal driving IC is bonded to a flexible tape having metal wiring, and they are bonded to a glass panel using an anisotropic conductive adhesive containing conductive particles. The anisotropy here means that it conducts in the pressurized direction and maintains the insulating property in the non-pressurized direction. As the conductive particles used in the anisotropic conductive adhesive, the conductive particles in which a metallic conductive layer is formed on the surface of the resin particles are the mainstream.

In recent years, in the field of electronic devices such as liquid crystal displays, personal computers, tablet PCs, and smartphones, the definition of electrode circuits has been increased and the area has been reduced, and it is necessary to reduce the size of conductive particles. However, with the miniaturization of the conductive particles, it is necessary to thin the conductive layer of the metal, and further, it is difficult to impart conductivity to the resin particles by the existing process. It is difficult to achieve both low resistance characteristics. Therefore, a new technique for improving the conductivity of conductive particles is required.

For example, Patent Document 1 discloses an anisotropic conductive adhesive characterized in that metal fine particle-supporting resin particles in which a plurality of metal fine particles are supported on the surface of the resin particles are dispersed in an adhesive component. There is.

Patent Document 2 is a conductive particle provided with a base resin particle, a plurality of nano-sized conductive particles, and a conductive layer, and is conductive by point-like bonding between a plurality of nano-sized conductive particles adhering to the surface of the base resin particle. Disclosed are conductive particles characterized by comprising a network and a conductive layer formed by plating on the nano-sized conductive particles.

Further, as a method for producing such conductive particles, Patent Document 3 is a method for producing conductive particles in which a conductive material having conductivity is coated on a core material as a base material, and the core material is covered with the conductive material. The kneading step includes a kneading step in which the conductive material smaller than the core material is charged and the charged core material and the conductive material are kneaded, and the kneading step is such that the conductive material is attached to the core material. A method for producing conductive particles, which comprises a torsional shearing step in which a shearing force is applied from a plurality of directions so as to adhere the conductive material to the core material while applying a compressive force to the core material. It is disclosed.

Japanese Unexamined Patent Publication No. 2002-245853 Japanese Unexamined Patent Publication No. 2010-033911 Japanese Unexamined Patent Publication No. 2011-228281

For example, the metal fine particles in the anisotropic conductive adhesive described in Patent Documents 1 to 3 are composed of metals capable of forming plating such as Au, Pt, Ni, Cu, and Ag, and are electrodes. It is said that when the particles are deformed by crimping each other, the metal fine particles adhere to each other and good conduction can be obtained. Further, it is said that the metal fine particles have an advantage that they do not have the problem that the metal film is broken during crimping and conduction cannot be ensured unlike the conventional metal film resin particles.

However, since the metal fine particles capable of forming plating have a high melting point, it is difficult to heat the electrodes together.

The present invention has been achieved in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide conductive particles capable of bonding electrodes between electrodes by heat and a method for producing the same.

As a result of diligent research, the present inventors have mixed a suspension of resin particles (dispersion liquid) and a suspension of tin alloy, and then agitated the resin, utilizing electrostatic force or intermolecular force. The tin alloy comprises a resin particle produced by a method of supporting a tin alloy on the surface of the particle and then heating in some cases, and a tin alloy supported so as to cover the surface of the resin particle, and the tin alloy forms a layer. It is said that the above-mentioned problems can be solved by the conductive particles for an anisotropic conductive film which are formed and whose average value of the layer thickness is 0.003 to 0.3 times the average particle size of the resin particles. The heading and the present invention have been completed.

According to the present invention, by providing conductive particles having a structure in which the surface of resin particles is covered with a tin alloy, highly conductive conductive particles capable of bonding between metals by heat and a difference using the same. It exerts an extremely excellent effect of being able to realize a conductive adhesive. Issues, configurations and effects other than those described above will be clarified by the following description of the embodiments.

It is a figure which shows typically an example of the basic structure of the conductive particle of this invention. It is a figure which shows typically an example of the basic structure of the conductive particle of another form of this invention. It is a figure which shows typically an example of the method of preparing the conductive particle of this invention. It is a figure which shows typically an example of the method of preparing the conductive particle of another form of this invention. It is a figure which shows typically an example of the manufacturing system of the conductive particle of this invention. It is a figure which shows typically an example of the manufacturing system of the conductive particle of another form of this invention. It is an SEM image which observed the conductive particle obtained in the Example of this invention. It is an SEM image which observed the conductive particle obtained in the Example of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the dimensions and shapes of each part are exaggerated for clarification, and the actual dimensions and shapes are not accurately depicted. Therefore, the technical scope of the present invention is not limited to the dimensions and shapes of the parts shown in these drawings. It is needless to say that the embodiment described later is an example, and other embodiments may be possible by combining each embodiment, combining with a known or well-known technique, or replacing the embodiment.

<Conductive particles>
The conductive particles for the anisotropic conductive film of the present invention include resin particles and a tin alloy supported so as to cover the surface of the resin particles, and the tin alloy forms a layer, and the thickness of the layer is formed. The average value of the tin particles is 0.003 to 0.3 times, preferably 0.01 to 0.1 times, and more preferably 0.03 to 0.1 times the average particle size of the resin particles.

When the ratio of the thickness of the resin particles to the tin alloy layer in the conductive particles is the above ratio, the conductive particles can be bonded between metals by heat, have heteroconductiveity, and have high conductivity. Become a sex particle. If the thickness of the tin alloy layer is too thin, conductivity cannot be ensured, and if it is too thick, the uniformity of the layer cannot be maintained. Therefore, it is important to control the thickness of the layer.

Here, examples of the resin particles include, but are not limited to, resin particles known in the art, and examples thereof include acrylic resins such as polymethylmethacrylate and polymethylacrylate, and polyolefin resins such as polyethylene, polypropylene, polyisobutylene, and polybutadiene. , Alcandiol di (meth) acrylate and / or a polymer such as divinylbenzene, polystyrene which is a polymer of styrene and the like can be mentioned. As the resin particles, a polymer such as alkanediol di (meth) acrylate and / or divinylbenzene is preferable from the viewpoint of recovery rate and the like.

The shape of the resin particles is usually spherical. Here, the sphere includes not only a true sphere but also an ellipsoid, an arbitrary rotating body, and the like, and for example, the aspect ratio is usually 0.5 or more, preferably 0.8 or more.

When the resin particles are the above-mentioned resin particles, the tin alloy is supported on the surface of the resin particles. Since the resin particles have a high sphericity and a uniform particle size distribution, the bonding area becomes constant, which facilitates thermal bonding.

The size of the resin particles is not limited as long as it falls within the range defined above with respect to the average value of the thickness of the layer formed by the tin alloy, but the average particle size is usually 0.1 μm to 10 μm, preferably 0. It is .5 μm to 3 μm. The average particle size of the resin particles can be measured by SEM.

When the size of the resin particles is within the above range, low resistance characteristics of the conductive particles are ensured.

Examples of the tin alloy include, but are not limited to, tin alloys known in the art, and for example, Sn-Pb type, Pb-Sn-Sb type, Sn-Sb type, which are alloys having a characteristic of low melting point. Examples thereof include Sn-Pb-Bi system, Bi-Sn system, Sn-Cu system, Sn-Pb-Cu system, Sn-Ag system, Sn-Pb-Ag system, Sn-In system and the like. As the tin alloy, Pb-free is preferable from the viewpoint of the environment, and Bi-Sn type and Sn-In type are preferable because low temperature bonding is possible. Furthermore, the Bi-Sn system is preferable from the viewpoint of bonding stability with respect to an external temperature.

When the composition of the tin alloy is the above-mentioned composition, the conductive particles become conductive particles having anisotropic conductivity and high conductivity which can be bonded between metals by heat.

The shape of the tin alloy forming the layer is a particle (spherical) shape (particulate tin alloy), a flaky shape such as a scale (flake tin alloy), or the like. The tin alloy may be a coating film that covers the entire surface of the resin particles (coated tin alloy). It is desirable that the tin alloy forming the layer has a uniform shape.

When the tin alloy has the above-mentioned shape, the conductive particles become highly conductive particles having anisotropic conductivity and capable of metal-to-metal bonding by heat.

The size of the tin alloy forming the layer is not limited as long as the thickness of the layer falls within the range defined above with respect to the average particle size of the resin particles.

For example, when the layer is composed of a particulate tin alloy, the size of the particulate tin alloy is not limited as long as the thickness of the layer falls within the range defined above with respect to the average particle size of the resin particles, but the average. The particle size is usually 0.001 μm to 1 μm, preferably 0.03 μm to 0.3 μm. The average particle size of the particulate tin alloy can be measured by SEM.

For example, when the layer is composed of a flake tin alloy, the size of the tin alloy is not limited as long as the thickness of the layer is within the range defined above with respect to the average particle size of the resin particles, but the length of the piece. The average value of the sides is usually 0.001 μm to 1 μm, preferably 0.03 μm to 0.3 μm. The average value of the long sides of the tin alloy piece can be measured by SEM.

The conductive layer formed of the tin alloy may be one layer or a plurality of layers, preferably 1 to 10 layers, and more preferably 1 to 5 layers.

The thickness of the layer formed by the tin alloy is not limited as long as it has the thickness defined above with respect to the average particle size of the resin particles, but the average value is usually 0.001 μm to 1 μm, preferably 0.03 μm. It is ~ 0.3 μm. The average value of the thickness of the layer formed by the tin alloy can be measured by SEM.

When the thickness of the layer formed by the tin alloy is within the above range, the conductive particles become highly conductive particles having anisotropic conductivity and capable of bonding between metals by heat.

The conductive particles for the anisotropic conductive adhesive of the present invention can be used for a connecting structure using an anisotropic conductive adhesive, for example, an adhesive film and an anisotropic conductive adhesive. The anisotropic conductive adhesive is used for adhering circuit members to each other and electrically connecting circuit electrodes of each circuit member. The anisotropic conductive adhesive contains an adhesive component and conductive particles, and the conductive particles are dispersed in the film-like adhesive. The concentration of the conductive particles in the anisotropic conductive adhesive is usually 5% by mass to 60% by mass, preferably 15% by mass to 50% by mass, based on the total weight of the anisotropic conductive adhesive.

FIG. 1 schematically shows a cross-sectional view of an example of the conductive particles 10 of the present invention and the anisotropic conductive adhesive 1 using the conductive particles 10. As shown in FIG. 1, the anisotropic conductive adhesive 1 has a structure in which the conductive particles 10 are uniformly dispersed in the film-shaped adhesive 12, and the conductive particles 10 are the surfaces of the resin particles 101. Has a structure covered with a layer formed of a plurality of particulate tin alloys 102.

In the anisotropic conductive adhesive 1 of FIG. 1, the anisotropic tin alloy 102 is melted by sandwiching the anisotropic conductive adhesive 1 containing the conductive particles 10 between the electrodes and applying heat to join the electrodes. do. The conductive particles 10 maintain conductivity in the direction between the electrodes (z direction), but since the conductive particles 10 are not in contact with each other, they maintain insulation in the surface direction (xy surface) of the adhesive 12.

FIG. 2 schematically shows a cross-sectional view of an example of the conductive particles 10 of another embodiment of the present invention and the anisotropic conductive adhesive 1 using the conductive particles 10. As shown in FIG. 2, the anisotropic conductive adhesive 1 has a structure in which the conductive particles 10 are uniformly dispersed in the film-shaped adhesive 12, and the conductive particles 10 are the surfaces of the resin particles 101. Has a structure covered with a layer formed of a tin alloy or a coated tin alloy 103.

Similar to FIG. 1, also in the anisotropic conductive adhesive 1 of FIG. 2, a layer formed of a tin alloy by sandwiching the anisotropic conductive adhesive 1 containing the conductive particles 10 between the electrodes and applying heat. Alternatively, the coated tin alloy 103 melts and joins the electrodes. The conductive particles 10 maintain conductivity in the direction between the electrodes (z direction), but since the conductive particles 10 are not in contact with each other, they maintain insulation in the surface direction (xy surface) of the adhesive 12.

<Manufacturing method of conductive particles>
In the method for producing conductive particles of the present invention, a suspension of resin particles and a suspension of a tin alloy, for example, a particulate tin alloy or a flake tin alloy are mixed and then stirred, and electrostatic force or intermolecular force is used. It involves using force to support a tin alloy on the surface of the resin particles.

Here, the suspension of the resin particles is a suspension of the resin particles known in the art, and as the resin particles, the resin particles described in the above <conductive particles> can be used. Examples of the suspension of the resin particles include a suspension in which crosslinked polystyrene particles activated by dimethylamine borane or the like are dispersed in distilled water.

By using the suspension of the resin particles as the suspension of the resin particles, the tin alloy can be supported on the surface of the resin particles.

The tin alloy suspension can be obtained by dispersing a particulate tin alloy having the composition described in the above <conductive particles> in a solvent and optionally pulverizing the suspension. As the pulverization method, a pulverization method known in the art can be used, and examples thereof include a bead mill. The shape of the tin alloy in the suspension of the tin alloy can be adjusted by the crushing conditions of the particulate tin alloy, for example, in the case of a bead mill, the bead diameter, crushing time, crushing temperature, solvent and the like. For example, when a soft metal such as a particulate tin alloy is crushed by a bead mill, the particulate tin alloy is not immediately crushed, but has an oval-shaped stretched shape. After that, by lengthening the pulverization treatment time, the particles are further stretched and gradually torn to be finely divided.

As an example of the method of supporting the tin alloy on the surface of the resin particles by utilizing the electrostatic force or the intermolecular force, an alternating lamination method using the electrostatic force and the like can be mentioned.

By mixing the suspension of the resin particles and the suspension of the tin alloy and then stirring the mixture, the tin alloy can be supported on the surface of the electrostatic resin particles by an electrostatic force or an intermolecular force.

Further, in another method of producing conductive particles of the present invention, a suspension of resin particles and a suspension of a tin alloy, for example, a particulate tin alloy or a flake tin alloy are mixed and then stirred. After the tin alloy is supported on the surface of the resin particles by using electrostatic force or intermolecular force, the tin alloy supported on the surface of the resin particles is melted by heating, and the surface of the resin particles is melted with the tin alloy. After covering, the tin alloy melted by cooling is solidified to form a film-like tin alloy on the surface of the resin particles.

Here, the heat treatment is usually carried out at 100 ° C. to 200 ° C., preferably 120 ° C. to 170 ° C., usually for 0.5 minutes to 5 minutes, preferably 0.5 minutes to 3 minutes.

By performing the heat treatment under the above conditions, the tin alloy supported on the surface of the resin particles can form a film on the surface of the resin particles.

FIG. 3 shows an example of the process of the method for producing the conductive particles 10 of the present invention.

First, the suspension containing the resin particles 101 and the suspension containing the particulate tin alloy 102 are stirred and mixed to support the particulate tin alloy 102 on the surface of the resin particles 101.

Next, by carrying out separation steps such as filtration and sedimentation, the particulate tin alloy 102 that was not supported is removed, and the conductive particles 10 are purified. Examples of the separation method include filter filtration for separating by particle size, sedimentation separation for separating by difference in particle size and mass, and separation method using the difference in flow velocity distribution with respect to particle size.

FIG. 4 shows an example of a process of a method for producing another form of the conductive particles 10 of the present invention.

First, the suspension containing the resin particles 101 and the suspension containing the particulate tin alloy 102 are stirred and mixed to support the particulate tin alloy 102 on the surface of the resin particles 101.

Next, by carrying out separation steps such as filtration and sedimentation, the particulate tin alloy 102 that was not supported is removed, and the conductive particles 10 are purified. Examples of the separation method include filter filtration for separating by particle size, sedimentation separation for separating by difference in particle size and mass, and separation method using the difference in flow velocity distribution with respect to particle size.

Further, the suspension containing the separated conductive particles 10 is heated to melt the particulate tin alloy 102 supported on the surface of the resin particles 101. By using the particulate tin alloy 102 having a melting point lower than the melting point of the resin particles 101, the melted particulate tin alloy 102 covers the surface of the resin particles 101 by the surface tension to form the coated tin alloy 103. After that, the suspension containing the conductive particles 10 is cooled, and the temperature of the liquid is lowered from the melting point of the particulate tin alloy 102, so that the coated tin alloy 103 solidifies.

<Manufacturing system for conductive particles>
The conductive particle manufacturing system of the present invention is for a container for a resin particle suspension for holding a suspension of resin particles and a resin particle suspension for feeding the suspension of resin particles. Liquid feed pump, a stirrer for resin particle suspension to stir the suspension of resin particles and prevent precipitation of resin particles, and a tin alloy suspension for holding a suspension of tin alloy. Container, a liquid feed pump for tin alloy suspension to feed the tin alloy suspension, and a tin alloy suspension to stir the tin alloy suspension and prevent the tin alloy from settling. A stirrer for turbid liquid, a mixing mechanism for mixing a suspension of resin particles and a suspension of tin alloy to support the tin alloy on the surface of the resin particles, and resin particles carrying the tin alloy on the surface. Conductivity that includes or comprises a separation mechanism for separating the unsupported tin alloy and a container for the tin alloy for holding a suspended suspension of the separated unsupported tin alloy. It is a system for producing sex particles. The devices are connected by an appropriate connection mechanism.

By using the system as the system for producing the conductive particles of the present invention, the conductive particles of the present invention can be efficiently produced.

Further, in another form of the conductive particle production system of the present invention, a container for resin particle suspension for holding a suspension of resin particles and a resin for feeding the suspension of resin particles are supplied. A liquid feed pump for particle suspension, a stirrer for resin particle suspension to stir the suspension of resin particles and prevent precipitation of resin particles, and a stirrer for holding a suspension of tin alloy. A container for the tin alloy suspension, a liquid feed pump for the tin alloy suspension for feeding the tin alloy suspension, and a stirring of the tin alloy suspension to prevent the tin alloy from settling. A stirrer for a tin alloy suspension, a mixing mechanism for mixing a suspension of resin particles and a suspension of tin alloy to support the tin alloy on the surface of the resin particles, and a tin alloy on the surface. A separation mechanism for separating the supported resin particles and the unsupported tin alloy, a container for the tin alloy for holding the separated suspension of the unsupported tin alloy, and a surface of the tin alloy. Contains a heating mechanism for melting the tin alloy by heating the resin particles carried on the resin particles to form a film-like tin alloy on the surface of the resin particles, and conductive particles for recovering the suspension that has passed through the heating mechanism. A system for producing conductive particles that include or are composed of a container for suspension. The devices are connected by an appropriate connection mechanism.

By further adding a heating mechanism to the system for producing conductive particles of the present invention, conductive particles containing the coated tin alloy of the present invention can be efficiently produced.

FIG. 5 schematically shows an example of a configuration diagram of the manufacturing system 11 for the conductive particles 10 of the present invention.

The manufacturing system 11 of the present invention is for a container 111 for holding a suspension of resin particles 1110 and a suspension for resin particles for feeding the suspension 1110 of resin particles. The liquid feed pump 112, the stirrer 113 for the resin particle suspension to stir the resin particle suspension 1110 and prevent the resin particles 101 (FIG. 3) from settling, and the tin alloy suspension 1140. A container 114 for a tin alloy suspension, a liquid feed pump 115 for a tin alloy suspension, and a tin alloy suspension 1140 for feeding the tin alloy suspension 1140. A stirrer 116 for a tin alloy suspension for stirring and preventing the precipitation of the particulate tin alloy 102 (FIG. 3), a resin particle suspension 1110 and a tin alloy suspension 1140 are mixed and the resin particles are mixed. A mixing mechanism 117 for supporting the particulate tin alloy 102 (FIG. 3) on the surface of 101 (FIG. 3), and resin particles 101 (FIG. 3) supporting the particulate tin alloy 102 (FIG. 3) on the surface. Separation mechanism 118 for separating unsupported particulate tin alloy 102 (FIG. 3) and particulate suspension 1190 for separated unsupported particulate tin alloy 102 (FIG. 3). For a container for tin alloy 102 (FIG. 3) and a suspension containing conductive particles for recovering a suspension containing conductive particles 10 that has passed through a separation mechanism 118 (suspension containing conductive particles 1200). Contains or consists of a container 120 of. The devices are connected by an appropriate connection mechanism, such as the connection mechanism 2011 of the container 111 for the resin particle suspension and the liquid feed pump 112 for the resin particle suspension.

FIG. 6 schematically shows an example of a configuration diagram of a manufacturing system 11 for the conductive particles 10 of another embodiment of the present invention.

The manufacturing system 11 of the present invention is for a container 111 for holding a suspension of resin particles 1110 and a container for a suspension of resin particles 1110 for feeding the suspension of resin particles 1110. The liquid feed pump 112, the stirrer 113 for the resin particle suspension for stirring the resin particle suspension 1110 to prevent the resin particles 101 (FIG. 4) from settling, and the tin alloy suspension 1140. A container 114 for a tin alloy suspension for holding the particles, a liquid feed pump 115 for a tin alloy suspension for feeding the tin alloy suspension 1140, and a tin alloy suspension 1140. A stirrer 116 for a tin alloy suspension for stirring and preventing the precipitation of the particulate tin alloy 102 (FIG. 4), a resin particle suspension 1110, and a tin alloy suspension 1140 are mixed and the resin particles are mixed. A mixing mechanism 117 for supporting the particulate tin alloy 102 (FIG. 4) on the surface of 101 (FIG. 4), and resin particles 101 (FIG. 4) supporting the particulate tin alloy 102 (FIG. 4) on the surface. A separation mechanism 118 for separating the unsupported particulate tin alloy 102 (FIG. 4) and a particulate for holding the separated suspension 1190 of the unsupported particulate tin alloy 102 (FIG. 4). The particulate tin alloy 102 (FIG. 4) is melted by heating the container for the tin alloy 102 (FIG. 4) and the resin particles 101 (FIG. 4) on which the particulate tin alloy 102 (FIG. 4) is supported on the surface. , A suspension containing the heating mechanism 119 for forming the coated tin alloy 103 (FIG. 4) on the surface of the resin particles 101 (FIG. 4) and the conductive particles 10 that have passed through the heating mechanism 119 (conducting particle-containing suspension). Containing or composed of a container 120 for a conductive particle-containing suspension for recovering the turbid liquid 1200). The devices are connected by an appropriate connection mechanism, such as the connection mechanism 2011 of the container 111 for the resin particle suspension and the liquid feed pump 112 for the resin particle suspension.

Examples of the stirring method of the two stirrers (113, 116) include a method of stirring the suspension by rotating a spatula or a magnetic stirrer.

Examples of the mixing method of the mixing mechanism 117 include a batch method in which the two liquids are stirred in a stirring tank and mixed, and a flow method in which the two liquids are flowed in a microchannel and mixed by a diffusion effect.

Examples of the separation method of the separation mechanism 118 include filter filtration, sedimentation separation, and a mechanism utilizing the difference in the flow velocity distribution.

Examples of the heating method of the heating mechanism 119 include a method of heating and cooling the container holding the target liquid, and a method of heating and cooling the flow path through which the target liquid flows.

[Preparation of conductive particles]
(Step a) Preparation of suspension of resin particles A resin whose surface is activated by adding crosslinked polystyrene particles having an average particle size of 3.0 μm to a 0.5 mass% dimethylamine borane solution adjusted to pH 6.0. Obtained particles. Then, the surface-activated resin particles were immersed in 20 mL of distilled water and ultrasonically dispersed to obtain a suspension of the resin particles.

(Step b) Preparation of suspension of tin alloy (1) Suspension of particulate tin alloy that has not been pulverized A particulate tin alloy (average particle size 5 μm, Bi-Sn system) is placed in isopropanol. A suspension was obtained by adding the particulate tin alloy so that the concentration was about 10% by mass based on the total weight of the suspension. The suspension was stirred by ultrasonic waves for 15 minutes, then allowed to stand for 80 minutes to settle and separate large metal particles, and the supernatant was recovered, so that the suspension was not pulverized to remove the large tin alloy. A suspension of particulate tin alloy was obtained.

(2) Suspension of pulverized flake tin alloy The concentration of the particulate tin alloy in isopropanol is adjusted to the total suspension weight of the particulate tin alloy (average particle size 5 μm, Bi-Sn system). A suspension was obtained by adding the mixture so as to be about 10% by mass. The obtained suspension was pulverized with a bead mill (manufactured by Nippon Coke & Co., Ltd., trade name "MSC-50") using φ0.2 mm zirconia particles having a weight of about 10% by mass based on the total weight of the suspension. went.

When a soft metal such as a particulate tin alloy was crushed with a bead mill, the metal particles were not crushed immediately, but were stretched into an oval shape. Further, by lengthening the pulverization treatment time, the particles were further stretched and gradually torn off, so that the particles could be made finer. In this example, the pulverization treatment was carried out for 360 minutes.

The suspension of the tin alloy after the pulverization treatment contained a stretched tin alloy as well as a finely divided tin alloy. In order to remove these stretched large tin alloys, the pulverized tin alloy suspension was stirred with ultrasonic waves for 15 minutes and then allowed to stand for 80 minutes to settle large metal particles. Then, the supernatant was recovered to obtain a suspension of a flake tin alloy that had been pulverized by removing a large tin alloy.

(Step c) Modification of tin alloy to the surface of resin particles 10 μL of a suspension of 6% resin particles was added to 100 μL of the suspension of tin alloy recovered in step b to obtain a mixed suspension. The mixed suspension was repeatedly mixed by inversion (0.5 minutes) and ultrasonically stirred (5 minutes) (24 times in total). Inversion mixing and ultrasonic agitation have the effect of preventing particle settling and particle agglutination and modifying the surface of one resin particle with a tin alloy.

[Evaluation of conductive particles]
The prepared conductive particles scanning electron microscope (S canning E lectron M icroscope, hereinafter SEM) was used to observe. The acquired SEM images are shown in FIGS. 7 and 8 (a) to 8 (d).

FIG. 7 shows a particulate tin alloy prepared in (1) of (step b) on the surface of the resin particles of the suspension of the resin particles prepared in (step a) in (step c). 8 (a) to 8 (d) are SEM images of the conductive particles on which the above-mentioned substances are carried. 6 is an SEM image of conductive particles carrying a flake tin alloy that has been pulverized in step b) (2).

In FIG. 7, it was confirmed that the particulate tin alloy was supported on the surface of the resin particles. Further, in FIGS. 8A to 8D, it was confirmed that the flake tin alloy was supported on the surface of the resin particles. From this result, it was confirmed that the resin particles having a tin alloy supported on the surface can be prepared by the method of the present specification.

The present invention is not limited to the above-described embodiment, and includes various modifications. For example, it is possible to add / delete / replace a part of the configuration of the embodiment with another configuration.

1: Heterogeneous conductive adhesive, 10: Conductive particles, 11: Manufacturing system, 12: Adhesive, 101: Resin particles, 102: Particle-like tin alloy, 103: Film-like tin alloy, 111: Resin particle suspension Liquid container, 112: Liquid feed pump for resin particle suspension, 113: Stirrer for resin particle suspension, 114: Container for tin alloy suspension, 115: For tin alloy suspension Liquid transfer pump, 116: Stirrer for tin alloy suspension 117: Mixing mechanism, 118: Separation mechanism, 119: Heating mechanism, 120: Container for suspension containing conductive particles 1110: Suspension of resin particles Turbid liquid, 1140: Suspension of tin alloy, 1190: Suspension of separated unsupported tin alloy, 1200: Suspension containing conductive particles, 2011: Container and resin for resin particle suspension Connection mechanism of liquid feed pump for particle suspension

Claims (8)

It comprises resin particles and a tin alloy supported so as to cover the surface of the resin particles, the tin alloy is a flake tin alloy, the tin alloy forms a layer, and the average value of the layer thickness is , 0.003 times to 0.3 Baidea an average particle diameter of the resin particles is, tin alloy, Sn-Pb-based, Pb-Sn-Sb-based, Sn-Sb-based, Sn-Pb-Bi-based, Bi -Sn based, Sn-Ag-based, Sn-Pb-Ag system, and at least one selected from the group consisting of Sn-In system (provided that tin alloy except if it contains Cu.) der Ru, different Conductive particles for square conductive films. The conductivity according to claim 1, wherein the resin particles are a polymer of polymethylmethacrylate, polymethylacrylate, polyethylene, polypropylene, polyisobutylene, polybutadiene, alcandiol di (meth) acrylate and / or divinylbenzene, or polystyrene. particle. An anisotropic conductive adhesive in which the conductive particles according to claim 1 or 2 are dispersed in a film-like adhesive. The resin particles, which include mixing the suspension of the resin particles and the suspension of the tin alloy, stirring the mixture, and supporting the tin alloy on the surface of the resin particles by utilizing electrostatic force or intramolecular force. A tin alloy supported so as to cover the surface of the resin particles is provided, and the tin alloy forms a layer, and the average value of the layer thickness is 0.003 to 0 times the average particle size of the resin particles. A method for producing conductive particles for anisotropic conductive film, which is 3 times larger. The method according to claim 4 , wherein the tin alloy suspension is obtained by pulverizing the particulate tin alloy. Further, the tin alloy supported on the surface of the resin particles is melted by heating, the surface of the resin particles is covered with the melted tin alloy, the tin alloy melted by cooling is solidified, and the coated tin alloy is formed on the surface of the resin particles. The method of claim 4 or 5 , comprising forming. A container for the resin particle suspension for holding the suspension of the resin particles, a liquid feed pump for the resin particle suspension for feeding the suspension of the resin particles, and a suspension of the resin particles. A stirrer for resin particle suspension to stir the liquid and prevent the precipitation of resin particles, a container for tin alloy suspension to hold the tin alloy suspension, and a tin alloy suspension. A liquid feed pump for tin alloy suspension, a stirrer for tin alloy suspension to stir the tin alloy suspension, and a stirrer for tin alloy suspension to prevent sedimentation of the tin alloy, and resin particles. A mixing mechanism for mixing the suspension and the suspension of the tin alloy to support the tin alloy on the surface of the resin particles, and for separating the resin particles supporting the tin alloy on the surface and the tin alloy not supported. Resin particles and a tin alloy supported to cover the surface of the resin particles, including a separation mechanism for the tin alloy and a container for the tin alloy for holding a separated suspension of the unsupported tin alloy. , And the tin alloy forms a layer, and the average value of the layer thickness is 0.003 to 0.3 times the average particle size of the resin particles. A system for producing sex particles. Further, the tin alloy is melted by heating the resin particles carrying the tin alloy on the surface, and the heating mechanism for forming the coated tin alloy on the surface of the resin particles and the suspension that has passed through the heating mechanism are recovered. 7. The system of claim 7 , comprising a container for a suspension containing conductive particles for the purpose.

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