JP2012072324A - Resin particle, insulated conductive particle using the same, and anisotropic conductive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin particle for insulation, which is hardly deformed on thermal compression bonding, in spite of low glass transition temperature (Tg).SOLUTION: The resin particle present on the surface of a conductive particle to insulate the conductive particle is characterized by containing a polymerizable component copolymer essentially containing at least an alkyl (meth)acrylate and a polyvalent (meth)acrylate, wherein the polyvalent (meth)acrylate is a compound in which the (meth)acryl groups are bound to each other through three or more carbon atoms.

Description

  The present invention is an insulated conductive material that exhibits good connection reliability when used for an electrical connection as an anisotropic conductive material such as an anisotropic conductive film (ACF) or an anisotropic conductive paste (ACP). The present invention relates to insulating resin particles capable of providing particles.

  Conventionally, an anisotropic conductive film (ACF) or anisotropic conductive paste (ACP) or the like is used when a mounting component is electrically connected to a glass substrate or printed wiring board such as a liquid crystal display or a plasma display. Conductive material is used. Such an anisotropic conductive material is generally obtained by dispersing conductive particles in a binder resin to form a film or a paste. Particles coated with a metal layer, metal particles, and the like have been widely used. However, with the recent miniaturization of electronic devices and electronic components, the pattern of connection terminals to be connected has become finer, and the pitch between adjacent electrodes has become narrower. This causes a problem that a short circuit occurs due to this conduction (so-called lateral conduction).

  As a means for solving the above-mentioned problems, it is known to use insulated conductive particles in which conductive metal layer surfaces of conductive particles are coated with insulating particles as an anisotropic conductive material. Insulating coated conductive particles (insulating) in which a coating layer made of an insulating resin having a specific thickness is formed on the surface of conductive fine particles whose average particle diameter, aspect ratio, and CV value are in a specific range. Conductive particles) have been proposed (Patent Document 1).

Japanese Patent Laid-Open No. 2000-100239

  However, according to the study by the present inventors, when the anisotropic conductive material using the insulated conductive particles of Patent Document 1 is used for electrical connection, lateral conduction still occurs. The glass transition temperature (Tg) of the insulating resin covering the insulated conductive particles specifically disclosed as an example in this document is as low as 60 ° C., and therefore, lateral conduction occurs. That is, in the case of insulated conductive particles using an insulating resin having a low Tg, the insulating resin on the surface is greatly deformed due to thermocompression when the anisotropic conductive material is used for electrical connection. The conductive particles of the matching insulated conductive particles come into contact with each other to cause lateral conduction. On the other hand, in Patent Document 1, although the reason for the low Tg is not mentioned, it is presumed that it is for ensuring the adhesion to the conductive fine particles. In other words, if the adhesion between the conductive fine particles and the insulating resin is insufficient, the insulating resin tends to fall off when subjected to electrical connection as an anisotropic conductive material, and a sufficient insulating effect cannot be obtained. It will be.

  Accordingly, an object of the present invention is to provide insulated conductive particles that can reliably suppress lateral conduction while maintaining good conduction between opposing electrodes when subjected to electrical connection as an anisotropic conductive material. There is. Another object of the present invention is to provide insulating resin particles that are not easily deformed during thermocompression bonding even though the glass transition temperature (Tg) is low. Another object of the present invention is to provide a technique for using the insulating resin particles.

  The present inventors have intensively studied to solve the above problems. As a result, by adopting a combination of an alkyl (meth) acrylate and a specific polyvalent (meth) acrylate as the polymerizable component constituting the resin particles for insulating the conductive particles, the heat is reduced while the Tg is low. It is found that the resin particles are not easily deformed even when crimped, and electrical connection is made with an anisotropic conductive material using insulated conductive particles insulated with such resin particles, and conduction between opposing electrodes is good. It was confirmed that lateral conduction could be reliably suppressed while maintaining the above, and the present invention was completed.

  That is, the resin particles according to the present invention are resin particles that are present on the surface of the conductive particles to insulate the conductive particles, and at least an alkyl (meth) acrylate and a polyvalent (meth) acrylate are essential. The polyvalent (meth) acrylate is characterized in that each (meth) acrylic group is bonded to each other via three or more carbon atoms. Preferably, the polyvalent (meth) acrylate is (A) a di (meth) acrylate obtained from an alkanediol having 3 or more carbon atoms, (B) a polyalkylene glycol di (meth) acrylate, and (C) an alkylene oxide-modified tri. One or more selected from the group consisting of methylolpropane triacrylate. The polyvalent (meth) acrylate is preferably 5% by mass or more based on the total amount of the polymerizable components.

  In the resin particles of the present invention, the glass transition temperature (Tg) is preferably 180 ° C. or less, the deformation rate obtained by a specific measurement method is preferably 60% or less, and the average particle size is 500 nm or less. And the coefficient of variation is preferably 50% or less.

The insulated conductive particles according to the present invention are characterized in that the resin particles of the present invention are present on at least a part of the surface of the conductive particles. In the insulated conductive particles of the present invention, the average particle diameter of the conductive particles is preferably 11 μm or less.
The anisotropic conductive material according to the present invention is characterized in that the insulated conductive particles according to the present invention are dispersed in a binder resin.

  According to the present invention, by using a predetermined polymerizable component as a copolymer component, resin particles having characteristics suitable for insulation that are low in Tg and difficult to be deformed are obtained, and the resin particles are used for conductivity. Insulates the particles, ensuring good adhesion between the resin particles and the conductive particles and suppressing deformation of the resin particles during thermocompression bonding, and facing when electrically connected as an anisotropic conductive material There is an effect that it is possible to provide insulated conductive particles capable of reliably suppressing lateral conduction while maintaining good conduction between the electrodes.

(Resin particles)
The resin particles of the present invention are used to insulate conductive particles, and have at least a polymerizable component (that is, a polymerizable group) having at least an alkyl (meth) acrylate and a specific polyvalent (meth) acrylate. A copolymer of a compound having In the present invention, “(meth) acrylate” means acrylate (acrylic acid ester) and / or methacrylate (methacrylic acid ester). Moreover, alkyl (meth) acrylate and a specific polyvalent (meth) acrylate are also referred to as essential polymerizable components.

  The alkyl (meth) acrylate that is the essential polymerizable component includes methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and (meth) acrylic acid. n-butyl, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-amyl (meth) acrylate, isoamyl (meth) acrylate, octyl (meth) acrylate, 2- (meth) acrylic acid 2- Examples thereof include (meth) acrylic acid esters having 1 to 18 carbon atoms in the alkyl group, such as ethylhexyl, decyl (meth) acrylate, lauryl (meth) acrylate, and cyclohexyl (meth) acrylate. Furthermore, a part of the hydrogen atom of the alkyl group is substituted with an aromatic ring such as benzyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, 3-phenylpropyl (meth) acrylate ( A (meth) acrylic acid ester is also included in the alkyl (meth) acrylate of the present invention. In particular, from the viewpoint of easily obtaining resin particles having a uniform particle diameter, the alkyl (meth) acrylate preferably contains at least methyl (meth) acrylate or ethyl (meth) acrylate, more preferably at least methacrylic. It may contain methyl acid.

  The specific polyvalent (meth) acrylate that is the essential polymerizable component is one in which each (meth) acrylic group (acrylic group and / or methacrylic group) is bonded to each other via three or more carbon atoms (hereinafter, “ It is important that the specific polyvalent (meth) acrylate is referred to. In other words, any two of the plurality of (meth) acryl groups possessed by the polyvalent (meth) acrylate have 3 or more carbon atoms present therebetween. Thus, when the particles include a copolymer composed of a polyvalent (meth) acrylate having a long distance between each (meth) acrylic group, the particles have a low Tg and have good adhesion to the conductive particles. Resin particles suitable for insulation that are difficult to deform while being held. The number of carbon atoms present between each (meth) acryl group may be at least 3 or more, but is preferably 4 or more. The number of (meth) acryl groups in the specific polyvalent (meth) acrylate is preferably 5 or less, more preferably 4 or less, still more preferably 3 or less, most preferably from the viewpoint of controlling Tg. Two is preferable. The specific polyvalent (meth) acrylate may be one in which an atom other than a carbon atom exists between each (meth) acryl group, and for example, an oxygen atom or a nitrogen atom may intervene. The number of atoms other than these carbon atoms is not particularly limited, but the number of all atoms (carbon atoms and atoms other than carbon atoms) present between each (meth) acryl group is preferably 4 or more, more preferably 5 or more.

  Specific examples of the specific polyvalent (meth) acrylate include (A) di (meth) acrylate obtained from alkanediol having 3 or more carbon atoms, (B) polyalkylene glycol di (meth) acrylate, and (C) alkylene oxide. One or more selected from the group consisting of modified trimethylolpropane triacrylate is preferred. The specific polyvalent (meth) acrylate may be only one kind or two or more kinds.

  Examples of the di (meth) acrylate obtained from the (A) alkanediol having 3 or more carbon atoms include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1, One or more selected from the group consisting of 9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate and 2-butyl-2-ethyl-1,3-propanediol di (meth) acrylate It is preferable that

  Examples of the (B) polyalkylene glycol di (meth) acrylate include polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, and poly (ethylene glycol-tetramethylene). Glycol) di (meth) acrylate, poly (propylene glycol-tetramethylene glycol) di (meth) acrylate, and polyethylene glycol-polypropylene glycol-polyethylene glycol di (meth) acrylate. Is preferred.

  The (C) alkylene oxide modified trimethylolpropane triacrylate is preferably at least one selected from the group consisting of ethylene oxide modified trimethylolpropane triacrylate and propylene oxide modified trimethylolpropane triacrylate.

  As the specific polyvalent (meth) acrylate, in addition to the above (A) to (C), for example, pentaerythritol triacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, trimethyloltrimethacrylate Propane or the like can be used.

  The ratio of the alkyl (meth) acrylate and the specific polyvalent (meth) acrylate (the former / the latter; mass ratio) is preferably 49 or less, more preferably 12 or less, still more preferably 10 or less, It is preferably 1.0 or more, more preferably 1.5 or more, and still more preferably 2.0 or more. When the ratio of the alkyl (meth) acrylate and the specific polyvalent (meth) acrylate is larger than the above range, the deformation rate of the resin particles tends to increase, whereas when smaller than the above range, the Tg tends to increase. There is.

  The total amount of the alkyl (meth) acrylate and the specific polyvalent (meth) acrylate is 70% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, most preferably based on the total amount of the polymerizable components. 100% by mass. When the total amount of the alkyl (meth) acrylate and the specific polyvalent (meth) acrylate is within the above range, it is easy to achieve both low Tg and difficulty of deformation.

  As the polymerizable component, in addition to the alkyl (meth) acrylate and the specific polyvalent (meth) acrylate, other polymerizable monomers having one or more polymerizable double bonds may be included. . Examples of other polymerizable monomers include the following.

  That is, examples of the polymerizable monomer having one polymerizable double bond include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, (meth) acrylic acid, glycidyl (meth) acrylate, and the like. (Meth) acrylic monomers may be mentioned. Moreover, as a polymerizable monomer having one polymerizable double bond, styrenes such as styrene, α-methylstyrene, paramethylstyrene, isopropenylstyrene, chlorostyrene; acrylonitrile, methacrylonitrile, ethacrylonitrile, phenyl Examples thereof also include unsaturated nitriles such as acrylonitrile; itaconic acid, maleic acid, fumaric acid or half-ester compounds thereof; vinyl toluene; and epoxy group-containing monomers such as allyl glycidyl ether.

Examples of the polymerizable monomer having two or more polymerizable double bonds include ethylene glycol di (meth) acrylate, diallyl phthalate, triallyl cyanate, and the like. The other polymerizable monomer may be only one kind or two or more kinds.
In addition, when the said polymerizable component also contains the other polymerizable monomer mentioned above, those total content is the sum total of alkyl (meth) acrylate and specific polyvalent (meth) acrylate which are essential polymerizable components The amount should be within the above range.

  The specific polyvalent (meth) acrylate is preferably 5% by mass or more based on the total amount of the polymerizable components. More preferably, the specific polyvalent (meth) acrylate is 8% by mass or more, and more preferably 10% by mass or more, based on the total amount of the polymerizable components. It is preferable that the content ratio of the specific polyvalent (meth) acrylate with respect to the total amount of the polymerizable component is larger because the deformation rate of the resin particles can be reduced. However, if the content ratio of the specific polyvalent (meth) acrylate with respect to the total amount of the polymerizable component is too large, there is a concern that the Tg becomes high. Therefore, the content ratio of the specific polyvalent (meth) acrylate is based on the total amount of the polymerizable component. It is preferably 50% by mass or less, more preferably 40% by mass or less, and further preferably 35% by mass or less.

  The resin particles of the present invention include a copolymer obtained by copolymerizing a polymerizable composition containing a polymerization initiator, an emulsifier, a solvent and the like as necessary together with the above-described polymerizable component. Furthermore, the resin particles of the present invention can contain a polymer component and a fine particle component other than the copolymer (a polymer composed of the above-described polymerizable component). However, in order for the resin particles of the present invention to exhibit a predetermined effect, it is preferable that the copolymer is a main component. Specifically, the copolymer is 80% by mass or more, preferably 90% by mass. As mentioned above, it is more preferable that it is 95 mass% or more, More preferably, it is 98 mass% or more.

  The glass transition temperature (Tg) of the resin particles of the present invention is preferably 180 ° C. or lower. More preferably, it is 150 degrees C or less, More preferably, it is 120 degrees C or less. When the Tg of the resin particles is as low as the above range, good adhesion to the conductive particles can be exhibited. However, if the Tg of the resin particles is too low, the resin particles are easily deformed. Therefore, the Tg of the resin particles is preferably 40 ° C. or higher, more preferably 50 ° C. or higher, and further preferably 60 ° C. or higher. In the present invention, the glass transition temperature (Tg) of the resin particles can be measured, for example, by the method described in Examples described later.

  The resin particles of the present invention preferably have a deformation rate of 60% or less determined by the following measurement method. More preferably, it is 55% or less, More preferably, it is 50% or less. The deformation rate represents the ease of deformation of the particles under a constant heating and pressurization, and if the numerical value is within the above range, the insulating conductivity in which the resin particles are present on the surface of the conductive particles. When the particles are made of an anisotropic conductive material and used for electrical connection, it is possible to reliably suppress lateral conduction while maintaining good conduction between the opposing electrodes. However, if the deformation rate of the resin particles is too small, there is a possibility that conduction between the electrodes may be insufficient. Therefore, the deformation rate is preferably 5% or more, more preferably 10% or more, and even more preferably 15 % Or more.

The method for measuring the deformation rate is as follows. That is, a predetermined amount of resin particles are filled in a cylindrical container, and the height h1 is first measured when the temperature is raised to 40 ° C. under a constant load of 0.5 MPa, and then 100 ° C. under a constant load of 0.5 MPa. The height h2 when the temperature is raised to is measured, and the deformation rate (%) is calculated from the obtained height h1 and height h2 based on the following formula.
Deformation rate (%) = [(h1-h2) / (H1-H2)] × 100
Here, H1 is the height when the container is filled with the predetermined amount of resin particles in the hexagonal closest packing (filling ratio: 74%), and the formula: H1 = (total volume of resin particles / 0.74) H2 is a height when the predetermined amount of resin particles are completely melted in the container, and the formula: H2 = total volume of resin particles / inside of the container The cross-sectional area is obtained by The total volume of the resin particles can be calculated by dividing the mass of the filled resin particles by the specific gravity of the resin particles, and the cross-sectional area inside the container can be calculated from the inner diameter of the container.

  The average particle size of the resin particles of the present invention is preferably 500 nm or less. More preferably, it is 400 nm or less, More preferably, it is 300 nm or less, Most preferably, it is 180 nm or less. For example, when insulating conductive particles are used for an anisotropic conductive material whose connection target is a fine pattern, it is desirable that the particle diameter of the insulating conductive particles is small, and the particle diameter is small as in the above range. If it is a resin particle, it can be made to adhere with favorable adhesiveness also to electroconductive particle with a small particle diameter. On the other hand, if the average particle size of the resin particles is too small, the insulation particle conductive particles tend to have insufficient suppression of lateral conduction between adjacent electrodes, and therefore the average particle size of the resin particles is 10 nm. The above is preferable, 30 nm or more is more preferable, and 50 nm or more is more preferable.

  In addition, the average particle diameter of the resin particle in this invention means the volume average particle diameter measured by a dynamic light scattering method.

The coefficient of variation (CV value) in the particle diameter of the resin particles of the present invention is preferably 50% or less, more preferably 40% or less in order to uniformly adhere to the conductive particles with good adhesion. More preferably, it is 30% or less, most preferably 20% or less. The variation coefficient of the particle diameter is a value obtained by applying the volume average particle diameter measured by the dynamic light scattering method and the standard deviation of the particle diameter 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 resin particles of the present invention is preferably 0.005 times or more, more preferably 0.01 times or more, and still more preferably 0.005 times or more the number average particle diameter of conductive particles to be insulated. It is preferably not less than 03 times and not more than 0.3 times the number average particle diameter of the conductive particles to be insulated, more preferably not more than 0.1 times, and further preferably not more than 0.08 times. If the size (average particle diameter) of the resin particles with respect to the conductive particles is within the above range, the resin particles can be adhered to the surface of the conductive particles with good adhesion.

  The resin particles of the present invention can be obtained, for example, by emulsion polymerization of the polymerizable composition containing the above-described polymerizable component. Of course, the polymerization method of the polymerizable composition is not limited to the emulsion polymerization method, but in particular, the emulsion polymerization method described later may be employed to reduce the particle size (specifically, 1 μm or less, preferably 500 nm). The following is preferable in that particles are easily obtained. Hereinafter, preferred embodiments of emulsion polymerization when polymerizing the polymerizable composition will be described.

  A preferred embodiment of emulsion polymerization is a polymerization step in which a polymerizable composition containing a polymerization initiator and a surfactant (emulsifier) together with the polymerizable component is emulsion-polymerized, and after the polymerization step, a surfactant is further added and ripened. A maturing step. Emulsion polymerization is usually performed in an aqueous dispersion medium.

  As the polymerization initiator used in the emulsion polymerization, a redox polymerization initiator formed by combining a hydrogen peroxide solution and at least one reducing agent selected from the group consisting of ascorbic acid, tartaric acid and sorbic acid may be used. preferable. Thereby, a particle polymer having a small particle size and a narrow particle size distribution can be obtained. As a method for adding the polymerization initiator, the aqueous hydrogen peroxide solution and the reducing agent may be made into aqueous solutions, respectively, and then the aqueous solution may be continuously or intermittently added to the reaction vessel. The total amount may be added in advance to the reaction vessel and the reducing agent may be added continuously.

  As the surfactant used in the polymerization step, an anionic emulsifier is preferable. Thereby, a particle polymer having a small particle size and a narrow particle size distribution can be obtained. Examples of the anionic emulsifier include sodium lauryl sulfonate and sodium dodecyl benzene sulfonate. Among these, sodium dodecyl benzene sulfonate is particularly preferable. The amount of the surfactant used in the polymerization step is preferably 0.05 to 10 parts by mass and more preferably 0.1 to 7 parts by mass with respect to 100 parts by mass of the total amount of polymerizable components.

  The emulsion polymerization in the polymerization step may be carried out by a known emulsion polymerization method. For example, a monomer dropping method, a pre-emulsion method, a batch charging polymerization method, etc. can be adopted, and a crosslinked particle polymer having a narrow particle size distribution is obtained. In addition, it is preferable to employ a monomer dropping method. The charging method of the polymerizable component, the polymerization initiator, the surfactant and the like are not particularly limited and may be appropriately set. Preferably, however, 5% by mass or more of the total polymerizable component and a part of the polymerization initiator are preliminarily set. After starting the emulsion polymerization using a polymerization mixture composed of a surfactant, the remaining polymerizable component and the polymerization initiator may be dropped separately or mixed. The polymerization temperature in the polymerization step is preferably 30 to 90 ° C. The polymerization time may be appropriately set according to the reaction rate determined from the charged amount of the polymerizable component and the residual amount in the reaction solution, but is usually about 1 to 12 hours, preferably about 2 to 8 hours.

  The aging step is performed after the polymerization step for the purpose of reducing unreacted polymerizable components or stabilizing the dispersion containing the particle polymer obtained by emulsion polymerization. At this time, by adding a surfactant, it is possible to prevent aggregation of the crosslinked particle polymer during aging. As the surfactant used in the aging step, the surfactant exemplified in the polymerization step (preferably an anionic emulsifier) can be used, and particularly preferably, the same surfactant as that used in the polymerization step is used. It is preferable to use a nonionic surfactant such as polyoxyethylene alkyl ether, for example. The amount of the surfactant used in the aging step is preferably 0.05 to 10 parts by mass and more preferably 0.1 to 7 parts by mass with respect to 100 parts by mass of the total amount of polymerizable components used in the emulsion polymerization.

  The aging temperature in the aging step is preferably 50 to 90 ° C, more preferably 70 to 85 ° C. By setting the aging temperature within the above range, the amount of the unreacted polymerizable component can be reduced while suppressing the aggregation of particles. The aging time may be appropriately set according to the reaction rate determined from the charged amount of the polymerizable component and the remaining amount in the reaction solution, but is usually about 1 to 12 hours, preferably about 2 to 8 hours.

(Insulated conductive particles)
The insulated conductive particles of the present invention are those in which the resin particles of the present invention are present on at least a part of the surface of the conductive particles. Such insulated conductive particles are such that resin particles that are hard to be deformed with good adhesion adhere to the surface of the conductive particles, and thus face each other when subjected to electrical connection as an anisotropic conductive material. It is possible to reliably suppress lateral conduction while maintaining good conduction between the electrodes.
First, the conductive particles will be described.
The conductive particles may be metal particles, or composite particles composed of base particles and a conductive metal layer covering at least a part of the surface of the base particles. The latter composite particles are preferred.

Examples of the metal particles include gold, silver, copper, platinum, iron, lead, aluminum, chromium, palladium, nickel, rhodium, ruthenium, antimony, bismuth, germanium, tin, cobalt, indium, nickel-phosphorus, nickel- Examples thereof include particles made of metals such as boron, metal compounds, and alloys thereof. Among these, metal particles selected from gold, silver, copper, and nickel are preferable in that they are excellent in conductivity and industrially inexpensive.
The shape of the metal particles is not particularly limited, and may be any of a spherical shape, a spheroid shape, a confetti shape, a thin plate shape, a needle shape, an eyebrow shape, etc., but a spherical shape is preferable, and a true spherical shape is particularly preferable. .

  There is no restriction | limiting in particular as base particle used for the said composite particle, What is used widely can be used. Examples of the material of the base particle include inorganic materials such as silica; silicone resin (polymethylsilsesquioxane, polyphenylsilsesquioxane), polyolefin resin (polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, poly Tetrafluoroethylene, polybutadiene, etc.), vinyl polymer resin ((meth) acrylic resin, styrene resin, (meth) acrylic-styrene resin, etc.), polysulfone, polycarbonate, phenolic resin, amino resin (melamine resin, melamine-benzoguanamine resin, Organic materials such as benzoguanamine resins) and urea resins; polysiloxanes obtained by hydrolysis / condensation of inorganic compounds such as polysiloxanes (preferably (meth) acryloxy group-containing silicone compounds) ) And an organic component vinyl polymer in any appropriate form (for example, one is dispersed in the other, one is a core particle and the other is a shell layer, the other is a shell / shell form, both at the molecular level) Or a mixed or mixed form of the organic-inorganic composite material. Among these, vinyl polymer resin ((meth) acrylic resin, styrene resin, (meth) acrylic-styrene resin, etc.), amino resin (melamine resin, melamine-benzoguanamine resin) in terms of having an appropriate elastic modulus and recovery characteristics. Benzoguanamine resin, etc.) and organic-inorganic composite materials are preferred. In particular, as the organic-inorganic composite material, those described in JP-A No. 2003-183337 and JP-A No. 8-81561 are preferably used.

The particle diameter of the base particles used for the composite particles is preferably 0.5 μm or more and 10.0 μm or less in number average particle diameter. If the average particle size is too small, the particles tend to aggregate when the conductive metal layer is coated by electroless plating or the like, and there is a possibility that a uniform conductive metal layer cannot be formed. On the other hand, if the average particle size is too large, the application uses are limited, such as difficulty in application when the interval between adjacent electrodes is narrow, and there is a tendency that the industrial application fields are reduced. The average particle diameter of the substrate particles is more preferably 1.0 μm or more and 5.0 μm or less, further preferably 1.2 μm or more and 3.0 μm or less, and most preferably 1.5 μm or more and 2.7 μm. It is as follows.
The number average particle diameter is specifically a number-based value measured by a precision particle size distribution measuring apparatus using the Coulter principle (for example, “Coulter Multisizer III type” manufactured by Beckman Coulter, Inc.). .

The coefficient of variation (CV value) in the particle diameter of the base particles used for the composite particles is preferably 10% or less, more preferably 7% or less, still more preferably 5% or less, and most preferably 4% or less. The coefficient of variation of the particle diameter is a value obtained by applying the following equation to the average particle diameter of the particles measured by a precision particle size distribution measuring apparatus using the Coulter principle and the standard deviation of the particle diameter of the particles. .
Coefficient of variation of particle diameter (%) = 100 × (standard deviation of particle diameter / number average particle diameter)

  The shape of the base particles used for the composite particles is not particularly limited, and may be any of, for example, a spherical shape, a spheroid shape, a confetti shape, a thin plate shape, a needle shape, an eyebrows shape, and a spherical shape is preferable. A true spherical shape is particularly preferable.

  The metal constituting the conductive metal layer is not particularly limited as long as it is a conductive compound. For example, metals and metals such as gold, silver, copper, platinum, iron, lead, aluminum, chromium, palladium, nickel, rhodium, ruthenium, antimony, bismuth, germanium, tin, cobalt, indium, nickel-phosphorus, nickel-boron Examples thereof include compounds and alloys thereof. Among these, gold, silver, copper, and nickel are preferable because they are excellent in conductivity and industrially inexpensive. Further, the conductive metal layer may be a single layer or multiple layers. In the case of multiple layers, for example, nickel-gold, nickel-palladium, nickel-palladium-gold, nickel-silver and the like are preferable. Can be mentioned.

  The thickness of the conductive metal layer is not particularly limited, but is preferably 10 to 500 nm, more preferably 20 to 400 nm, and still more preferably 50 to 300 nm. When the thickness of the conductive metal layer is less than 10 nm, there is a possibility that stable electrical connection is difficult to be obtained when insulating conductive particles are used. When the thickness of the conductive metal layer exceeds 500 nm, the surface hardness of the conductive particles becomes too high, and the mechanical properties such as the recovery rate may decrease.

  The conductive metal layer in the composite particles only needs to cover at least a part of the surface of the base particle, but the surface of the conductive metal layer has substantial cracks or a conductive metal layer formed. It is preferred that no surface is present. Here, “there is no substantial crack or surface on which no conductive metal layer is formed” means that the surface of any 10,000 conductive particles was observed using an electron microscope (magnification 2000 times). Sometimes it means that the proportion of cracking of the conductive metal layer or exposure of the surface of the substrate particles is 5% or less.

  The method of coating the surface of the substrate particles with the conductive metal layer is not particularly limited, and a conventionally known method, for example, a method of performing plating such as an electroless plating method or an electrolytic plating method; A method of coating the base particles with a paste mixed with a binder; a physical vapor deposition method such as vacuum deposition, ion plating, ion sputtering, etc. may be employed. 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.

  In the electroless plating method, first, a catalyst layer is formed on the surface of the base particle as a base point for the next electroless plating treatment. As a method for forming the catalyst layer, for example, a solution containing palladium dichloride and tin dichloride is used as a catalyst reagent, and the catalyst particles are adsorbed on the surface of the substrate particles by immersing the substrate particles in the solution. In addition, by reducing the palladium ions with an alkali solution such as sulfuric acid or hydrochloric acid or an alkali solution such as sodium hydroxide, a method of depositing palladium on the surface of the substrate particles (catalyst-acceleration method), A method (sensitizing-activation method) in which palladium is deposited on the surface of the substrate particles by adsorbing tin ions on the surface of the substrate particles by contacting with tin dichloride and then dipping in a palladium dichloride solution. Can be mentioned.

In the electroless plating method, subsequently, the surface of the substrate particles on which the catalyst layer is formed is subjected to an electroless plating treatment to form a conductive metal layer. The electroless plating treatment involves immersing the base material particles on which the catalyst layer is formed in a plating solution in which a reducing agent and a desired conductive metal salt are dissolved, thereby starting metal ions in the plating solution from the catalyst. And a desired metal is deposited on the surface of the substrate particles to form a conductive metal layer. Examples of the conductive metal salt contained in the electroless plating solution include chlorides, sulfates, acetates, and the like of the metals exemplified above as the metal constituting the conductive metal layer.
The electroless plating treatment may be repeated as necessary. For example, by repeating the electroless plating process using electroless plating solutions having different metal types, the surface of the substrate particles can be coated with several layers of different metals. Specifically, after nickel plating is performed on the substrate particles to obtain nickel-coated particles, the outermost layer is a gold layer by adding the nickel-coated particles to an electroless gold plating solution and performing gold displacement plating. The electroconductive particle which is covered with and has a nickel layer inside is obtained.

The average particle size of the conductive particles obtained as described above is preferably 11 μm or less, more preferably 6.0 μm or less, still more preferably 4.0 μm or less, and particularly preferably 2. 8 μm or less. Conductive particles having a small particle diameter as in the above range are suitable for use in, for example, an anisotropic conductive material having a connection terminal with a fine pattern as a connection target. The necessity of using conductive particles (insulated conductive particles) provided with resin particles is increased, and the effects of the present invention are further remarkable. The average particle diameter of the conductive particles is preferably 1.1 μm or more, more preferably 1.3 μm or more, and further preferably 1.6 μm or more.
In addition, the average particle diameter of the electroconductive particle in this invention means the number average particle diameter measured by a flow type particle image analyzer (for example, "FPIA-3000" by Sysmex Corporation).

  As a method for fixing the above-described resin particles of the present invention on the surface of the conductive particles, a conventionally known coating method can be employed. For example, a method in which conductive particles after electroless plating treatment and the resin particles of the present invention are dispersed in a liquid such as an organic solvent or an aqueous medium and then spray-dried; in a liquid such as an organic solvent or an aqueous medium Method of attaching resin particles to the surface of conductive particles and then chemically bonding the conductive particles and resin particles; stirring and hybridization using a high-speed stirrer in the presence of conductive powder and resin particle powder And the like.

  The resin particles only need to be present on at least part of the surface of the conductive particles, and the abundance ratio of the resin particles in the entire surface of the conductive particles (in other words, the coverage of the conductive particles by the resin particles) is: Preferably they are 1% or more and 95% or less, More preferably, they are 5% or more and 90% or less, More preferably, they are 10% or more and 85% or less. When the coverage of the conductive particles by the resin particles is within the above range, it is possible to reliably insulate adjacent insulated conductive particles while ensuring sufficient electrical conductivity. In addition, the said coverage is the coating | cover of the resin particle in the orthographic projection surface of insulated conductive particles, when the surface of arbitrary 100 insulated conductive particles is observed using an electron microscope (5000 times magnification), for example It can be evaluated by measuring the area ratio of the portion that is not covered with the resin particles.

(Anisotropic conductive material)
The anisotropic conductive material of the present invention is obtained by dispersing the insulated conductive particles of the present invention in a binder resin. The form of the anisotropic conductive material is not particularly limited. For example, the anisotropic conductive film, the anisotropic conductive paste, the anisotropic conductive adhesive, the anisotropic conductive ink, or the like between the opposing substrates or The thing which enables an electrical connection by providing between electrode terminals is mentioned. The anisotropic conductive material of the present invention also includes a conductive material for liquid crystal display elements such as a conductive spacer and its composition.

  There is no restriction | limiting in particular as said binder resin, A conventionally well-known binder resin can be used. For example, thermoplastic resins such as (meth) acrylate resins, ethylene-vinyl acetate resins, styrene-butadiene block copolymers; curable resin compositions obtained by reaction with curing agents such as monomers and oligomers having glycidyl groups and isocyanates Examples thereof include curable resin compositions by light and heat.

  For example, the anisotropic conductive film is made into a liquid by adding a solvent to the film-forming composition containing the insulated conductive particles of the present invention and a binder resin, and this liquid is applied on a film made of polyethylene terephthalate or the like. It can be obtained by evaporating the solvent. The obtained anisotropic conductive film is disposed on electrodes, for example, and is used for connection between the electrodes by superposing a counter electrode on the anisotropic conductive film and heating and compressing it.

  An anisotropic conductive paste is obtained by making the resin composition containing the insulated conductive particle of this invention, binder resin, etc. into paste form, for example. The obtained anisotropic conductive paste is placed in, for example, a suitable dispenser, applied on the electrode to be connected with a desired thickness, and the counter electrode is superimposed on the coated anisotropic conductive paste. It is used for connection between electrodes by curing the resin by applying pressure while heating.

  The anisotropic conductive adhesive is obtained, for example, by adjusting a resin composition containing the insulated conductive particles of the present invention and a binder resin to a desired viscosity. The obtained anisotropic conductive adhesive is used to connect between electrodes by coating the electrodes with a desired thickness, then overlaying the counter electrodes and bonding them together, as with the anisotropic conductive paste. Is done.

  The anisotropic conductive ink can be obtained, for example, by adding a solvent to the resin composition containing the insulated conductive particles of the present invention and a binder resin to adjust the viscosity to be suitable for printing. The obtained anisotropic conductive ink is obtained by, for example, screen-printing on the electrode to be bonded, evaporating the solvent, superimposing the counter electrode on the printing surface with the anisotropic conductive ink, and heating and compressing the electrode. Used for connection between.

  In the anisotropic conductive material of the present invention, the content of the insulated conductive particles of the present invention may be appropriately determined according to the application, for example, 2 to 70 volumes with respect to the total amount of the anisotropic conductive material. % Is preferred. More preferably, it is 5 volume% or more, More preferably, it is 10 volume% or more, More preferably, it is 50 volume% or less, More preferably, it is 40 volume% or less. If the content of insulated conductive particles is too small, it may be difficult to obtain sufficient electrical continuity. On the other hand, if the content of insulated conductive particles is too large, the particles may come into contact with each other, resulting in a difference. In some cases, the function as an anisotropic conductive material is 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 insulated conductive particles of the present invention to be used and the electrode to be connected Considering the specifications, the insulating conductive particles are sandwiched between the electrodes to be connected, and appropriately set so that the gap between the bonding substrates on which the electrodes to be connected are formed is sufficiently filled with the binder resin layer It is preferable to do.

  There is no particular limitation on the connection method when the connection parts are electrically connected using the anisotropic conductive material of the present invention. For example, the temperature at the time of connection is preferably 190 ° C. or lower, more preferably 170 ° C. or lower, further preferably 150 ° C. or lower, preferably 80 ° C. or higher, more preferably 100 ° C. or higher, and further preferably 120 ° C. or higher. is there. The pressure at the time of connection is usually 1 to 100 MPa. The connection time (time for applying heat and pressure) may be appropriately set according to temperature and pressure, but is usually 10 seconds to 3600 seconds.

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 description, “part” means “part by mass” unless otherwise specified.

Various physical properties of the resin particles obtained in the following examples and comparative examples were measured by the following methods.
<Average particle size and coefficient of variation (CV value)>
The dispersion in which the resin particles are dispersed is measured by a dynamic light scattering particle size distribution measuring device (“NICOMP 380” manufactured by PS Japan Co., Ltd.) to determine the volume average particle size, and the coefficient of variation (CV) of the particle size according to the following formula: Value).
Variation coefficient of particle diameter (%) = 100 × (standard deviation of particle diameter / volume average particle diameter)

<Glass transition temperature (Tg)>
From the dispersion liquid in which the resin particles are dispersed, the precipitated cake that has been subjected to solid-liquid separation with a centrifugal separator is taken out, and further, moisture is removed with a vacuum dryer to isolate only the resin particles, and this is used as a sample.
Using a differential scanning calorimeter ("EXSTAR6000" manufactured by Seiko Instruments Inc.), the sample rate is 10 mg to 20 mg under a nitrogen stream (flow rate 50 mL / min), and the heating rate is 10 ° C from -10 ° C to 200 ° C. The sample was heated under the conditions of / min and measured. Specifically, first, a sample is weighed in a specified aluminum pan, and set together with a reference aluminum pan (without a sample) at a predetermined position of a differential scanning calorimeter, and nitrogen is supplied at a specified flow rate (50 mL / min). ) After the flow was adjusted and the apparatus was stabilized, the first temperature increase was started. After the temperature was raised from −10 ° C. to 200 ° C., it was once cooled, and then the second temperature was raised under the same conditions as the first time. Based on the baseline shift of the DSC curve obtained at this time, the glass transition temperature of the resin particles was calculated.

<Deformation rate>
From the dispersion liquid in which the resin particles are dispersed, the precipitated cake that has been subjected to solid-liquid separation with a centrifugal separator is taken out, and further, moisture is removed with a vacuum dryer to isolate only the resin particles, and this is used as a sample.
About 0.5 g of the obtained sample (resin particles) is precisely weighed and filled into a cylindrical cylinder (inner diameter 10 mmφ, no die hole) provided in a flow tester (“CFT-500” manufactured by Shimadzu Corporation) First, the height h1 (mm) of the sample when the temperature was raised to 40 ° C. under a constant load of 0.5 MPa was measured. Subsequently, the height h2 (mm) when the temperature was raised to 100 ° C. under a constant load of 0.5 MPa was measured. Then, the deformation rate (%) was calculated based on the following formula from the obtained height h1 and height h2.
Deformation rate (%) = [(h1-h2) / (H1-H2)] × 100

In the above formula, H1 is a height (mm) when the predetermined amount (the precisely weighed mass) of resin particles is hexagonally close packed (filling rate: 74%) in the container (cylinder). formula:
H1 = (total volume of resin particles / 0.74) / value obtained from the cross-sectional area inside the container. H2 is the height (mm) when the predetermined amount (the precisely weighed mass) of resin particles is completely melted in the container (cylinder).
H2 = value obtained from the total volume of resin particles / the cross-sectional area inside the container. Here, the total volume of the resin particles can be calculated by dividing the mass of the filled resin particles by the specific gravity of the resin particles, and the cross-sectional area inside the container can be calculated from the inner diameter of the cylinder.

Example 1
[Production of resin particles]
To a stainless steel reaction kettle equipped with a stirrer, a thermometer and a cooler, 820 parts of deionized water and 0.8 part of sodium dodecylbenzenesulfonate (active ingredient 60% by mass; hereinafter referred to as “DBSNa”) were added. The temperature was raised to 75 ° C. and kept at the same temperature.
On the other hand, in a container different from the reaction kettle, 180 parts of methyl methacrylate (hereinafter referred to as “MMA”) and 20 parts of polyethylene glycol diacrylate (hereinafter referred to as “PEGDA”) are mixed to obtain a mixture 200 of polymerizable components. Parts were prepared.

After replacing the inside of the reaction kettle with nitrogen gas, 20 parts of the mixture of the polymerizable components (10% by mass of the total amount of the polymerizable components), 50 parts of 0.4% by mass hydrogen peroxide, and 0.4% by mass -An initial polymerization reaction was carried out by adding 50 parts of an ascorbic acid aqueous solution to the reaction kettle.
Then, 180 parts of the mixture of the polymerizable components (90% by mass of the total polymerizable component), 450 parts by mass of 0.4% by mass hydrogen peroxide water, and 450 parts by mass of 0.4% by mass L-ascorbic acid aqueous solution, It was dripped uniformly into the reaction kettle over 6 hours from different charging ports. Thereafter, the internal temperature was raised to 90 ° C. and held at the same temperature for 6 hours for aging, and then the reaction solution was cooled to obtain a resin particle dispersion (1) in which the resin particles (1) were dispersed. Various physical properties of the resin particles (1) were as shown in Table 1.

[Preparation of conductive particles]
Polyoxyethylene styrenated phenyl ether sulfate ammonium salt (Daiichi Kogyo Seiyaku "Hitenol (registered trademark) NF-08") as a surfactant in a four-necked flask equipped with a condenser, thermometer, and dripping port ) 150 parts of an aqueous solution prepared by dissolving 2 parts in deionized water. Then, a mixture of 45 parts of divinylbenzene (active ingredient 81% by mass, hereinafter referred to as “DVB”), 50 parts of 1,6-hexanediol diacrylate and 5 parts of methacrylic acid prepared in advance, and a polymerization initiator 2 parts of 2,2′-azobis (2,4-dimethylvaleronitrile) (“V-65” manufactured by Wako Pure Chemical Industries, Ltd.) was added and emulsified and dispersed to prepare a suspension. To the obtained suspension, 250 parts of deionized water was further added, the temperature was raised to 65 ° C. under a nitrogen atmosphere, and the mixture was held at the same temperature for 2 hours to perform radical polymerization.

  Next, the emulsion obtained by radical polymerization is subjected to solid-liquid separation, and the obtained cake is washed with deionized water, subsequently washed with methanol, and further subjected to a classification operation, followed by 120 ° C. in a nitrogen atmosphere. And vacuum drying for 2 hours to obtain vinyl polymer particles. When the particle size of the polymer particles was measured with a particle size distribution analyzer (“Coulter Multisizer III type” manufactured by Beckman Coulter, Inc.), the number average particle size was 2.5 μm and the variation coefficient was 3.9%.

Using the polymer particles as base particles, the base particles are sensitized with a tin dichloride (SnCl ₂ ) solution and subsequently activated with a palladium dichloride (PdCl ₂ ) solution. Pd nuclei were formed. By soaking the particles in which the Pd nuclei are formed in an electroless nickel plating bath, Ni particles are applied to the surface of the particles, and then the nickel layer surface of the obtained particles is further subjected to gold plating by displacement plating, Conductive particles (1) having a metal layer thickness of 0.1 μm and a number average particle diameter of 2.7 μm were obtained.

In the examples of the present specification, the number average particle diameter of the conductive particles and the film thickness of the metal layer were measured and calculated as follows.
Number average particle diameter of conductive particles: measured by a flow type particle image analyzer (“FPIA-3000” manufactured by Sysmex Corporation), and the average particle diameter based on the number was defined as the number average particle diameter of the conductive particles.
Film thickness of the metal layer: The number average particle diameter of the polymer particles used for the base particles is measured by the above flow type particle image analyzer, and the obtained number average particle diameter and the conductive particles obtained by the above measurement 1/2 of the difference from the number average particle diameter was taken as the film thickness of the metal layer.

[Preparation of insulated conductive particles]
The resin particle dispersion (1) was diluted with deionized water so that the particle concentration was 5.0% by mass. After adding 50 parts of conductive particles (1) to 100 parts of the obtained resin particle dispersion and dispersing uniformly, water is distilled off with an evaporator, and the surface of the conductive particles is covered with resin particles. Conductive particles (1) were obtained.

[Production of anisotropic conductive material]
Insulating conductive particles (1) 20 parts, epoxy resin (“YL980” manufactured by Japan Epoxy Resin Co., Ltd.) 65 parts, epoxy curing agent (“Novacure (registered trademark) HX3941HP” manufactured by Asahi Kasei Co., Ltd.) 35 parts, and 1 mmφ 200 parts of zirconia beads were mixed and subjected to bead mill dispersion for 30 minutes to obtain an anisotropic conductive adhesive (1) as an anisotropic conductive material.

A conductive connection structure was prepared using the obtained anisotropic conductive adhesive, and the following evaluation was performed. The results are shown in Table 1.
The production of the conductive connection structure is first anisotropic so that the release thickness of the release film (polyethylene terephthalate film that has been subjected to release treatment on one side with silicone resin or fluororesin) is 25 μm. The anisotropic conductive sheet which formed the contact bonding layer by apply | coating a conductive conductive adhesive, and was equipped with the adhesive bond layer on the single side | surface of the release film was produced.
Next, the release film is peeled from the obtained anisotropic conductive sheet, and only the adhesive layer is placed between two ITO-attached glass substrates on which an ITO transparent electrode film having a 150 μm wide pattern is formed on the inner surface. The conductive connection structure was obtained by heating and pressurizing at 5 MPa and 185 ° C. for 15 seconds.

<Conductivity>
Using the conductive connection structure as a measurement sample, the conduction resistance between the opposing electrodes was measured by the four-terminal method. Measurement was performed at n = 50, and the ratio (%) at which the resistance value was 20Ω or less was determined.

<Insulation>
Using the conductive connection structure as a measurement sample, the insulation resistance between adjacent electrodes was measured by the four-terminal method. The measurement was performed at n = 50, and the ratio (%) at which the resistance value was 1000 MΩ or more was obtained.

(Example 2)
In the preparation of the resin component in Example 1 [Preparation of resin particles], 180 parts of MMA and a 6-mole ethylene oxide adduct of trimethylolpropane triacrylate (hereinafter referred to as “TMP-6EO-3A”) 20 A resin particle dispersion (2) in which the resin particles (2) are dispersed was obtained in the same manner as in Example 1 except that the parts were mixed. Various physical properties of the resin particles (2) were as shown in Table 1.
Next, in Example 1 [Production of insulated conductive particles], the insulated conductive film was used in the same manner as in Example 1 except that the resin particle dispersion liquid (2) was used instead of the resin particle dispersion liquid (1). Conductive particles (2) were obtained, and in Example 1 [Production of anisotropic conductive material], the insulated conductive particles (2) were used instead of the insulated conductive particles (1). In the same manner as in Example 1, an anisotropic conductive adhesive (2) was obtained.
Evaluation similar to Example 1 was performed about the obtained anisotropic conductive adhesive. The results are shown in Table 1.

(Example 3)
The same as Example 1 except that the amount of polyoxyethylene styrenated phenyl ether sulfate ammonium salt used as the surfactant in [Production of conductive particles] in Example 1 was changed from 2 parts to 5 parts. Thus, polymer particles were obtained. When the particle size of the polymer particles was measured with a particle size distribution analyzer (“Coulter Multisizer III type” manufactured by Beckman Coulter, Inc.), the number average particle size was 1.8 μm and the coefficient of variation was 4.2%. Conductive particles (3) having a metal layer thickness of 0.1 μm and a number average particle diameter of 2.0 μm, as in Example 1, except that the polymer particles were used as base particles. Got.
Then, in [Production of insulated conductive particles] in Example 1, insulated conductive particles were obtained in the same manner as in Example 1 except that the conductive particles (3) were used instead of the conductive particles (1). Example 3 was obtained, except that the insulated conductive particles (3) were used instead of the insulated conductive particles (1) in Example 1 [Production of anisotropic conductive material]. In the same manner, an anisotropic conductive adhesive (3) was obtained.
Evaluation similar to Example 1 was performed about the obtained anisotropic conductive adhesive. The results are shown in Table 1.

(Comparative Example 1)
Resin particles for comparison (C1) in the same manner as in Example 1 except that MMA 160 parts and DVB 40 parts were mixed in preparing the mixture of polymerizable components in [Production of resin particles] in Example 1. A resin particle dispersion (C1) in which was dispersed was obtained. Various physical properties of the resin particles (C1) were as shown in Table 1.
Next, in Example 1 [Production of insulated conductive particles], the insulated conductive film was used in the same manner as in Example 1 except that the resin particle dispersion liquid (C1) was used instead of the resin particle dispersion liquid (1). Conductive particles (C1) were obtained, and in Example 1 [Production of anisotropic conductive material], the insulated conductive particles (C1) were used in place of the insulated conductive particles (1). An anisotropic conductive adhesive (C1) was obtained in the same manner as in Example 1.
Evaluation similar to Example 1 was performed about the obtained anisotropic conductive adhesive. The results are shown in Table 1.

(Comparative Example 2)
Resin particles for comparison (C2) in the same manner as in Example 1 except that MMA 190 parts and DVB 10 parts were mixed in preparing the mixture of polymerizable components in [Production of resin particles] in Example 1. A resin particle dispersion (C2) in which was dispersed was obtained. Various physical properties of the resin particles (C2) were as shown in Table 1.
Then, in [Production of insulated conductive particles] in Example 1, insulated conductive material was obtained in the same manner as in Example 1 except that the resin particle dispersion (C2) was used instead of the resin particle dispersion (1). Conductive particles (C2) were obtained, and in Example 1 [Production of anisotropic conductive material], the insulated conductive particles (C2) were used in place of the insulated conductive particles (1). In the same manner as in Example 1, an anisotropic conductive adhesive (C2) was obtained.
Evaluation similar to Example 1 was performed about the obtained anisotropic conductive adhesive. The results are shown in Table 1.

(Comparative Example 3)
Resin particles for comparison (C3) in the same manner as in Example 1 except that 198 parts of MMA and 2 parts of DVB were mixed in preparing the mixture of polymerizable components in [Production of resin particles] in Example 1. A resin particle dispersion (C3) in which was dispersed was obtained. Various physical properties of the resin particles (C3) were as shown in Table 1.
Then, in [Production of insulated conductive particles] of Example 1, insulated conductive material was obtained in the same manner as in Example 1 except that the resin particle dispersion (C3) was used instead of the resin particle dispersion (1). Conductive particles (C3) were obtained, and in Example 1 [Production of anisotropic conductive material], the insulated conductive particles (C3) were used in place of the insulated conductive particles (1). In the same manner as in Example 1, an anisotropic conductive adhesive (C3) was obtained.
Evaluation similar to Example 1 was performed about the obtained anisotropic conductive adhesive. The results are shown in Table 1.

(Comparative Example 4)
Resin for comparison in the same manner as in Example 1 except that 198 parts of MMA and 2 parts of ethylene glycol dimethacrylate were mixed in preparing the mixture of polymerizable components in [Production of resin particles] in Example 1. A resin particle dispersion (C4) in which the particles (C4) were dispersed was obtained. Various physical properties of the resin particles (C4) were as shown in Table 1.
Next, in Example 1 [Production of insulated conductive particles], the insulated conductive film was used in the same manner as in Example 1 except that the resin particle dispersion (C4) was used instead of the resin particle dispersion (1). Conductive particles (C4) were obtained, and in Example 1 [Production of anisotropic conductive material], the insulated conductive particles (C4) were used in place of the insulated conductive particles (1). An anisotropic conductive adhesive (C4) was obtained in the same manner as in Example 1.
Evaluation similar to Example 1 was performed about the obtained anisotropic conductive adhesive. The results are shown in Table 1.

  From Table 1, it can be seen that the resin particles of Examples 1 to 3 composed of the specific polyvalent (meth) acrylate according to the present invention have low Tg and low deformation rate. Since such resin particles have a low Tg, they can exhibit good adhesion to the conductive particles and have a low deformation rate. Therefore, the resin particles are heated under a high pressure condition of 5 MPa while being present on the surface of the conductive particles. Even if it is crimped, it is difficult to be deformed. As a result, it was possible to reliably suppress lateral conduction while maintaining good conductivity between the opposing electrodes.

Claims (12)

  A resin particle which is present on the surface of conductive particles and insulates the conductive particles, and is a copolymer of a polymerizable component which essentially contains at least alkyl (meth) acrylate and polyvalent (meth) acrylate. In addition, the polyvalent (meth) acrylate is a resin particle in which each (meth) acryl group is bonded to each other via three or more carbon atoms.   The polyvalent (meth) acrylate is (A) a di (meth) acrylate obtained from an alkanediol having 3 or more carbon atoms, (B) a polyalkylene glycol di (meth) acrylate and (C) an alkylene oxide-modified trimethylolpropane tri The resin particle according to claim 1, which is at least one selected from the group consisting of acrylates.   The di (meth) acrylate obtained from the (A) alkanediol having 3 or more carbon atoms is 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonane. One or more selected from the group consisting of diol di (meth) acrylate, 1,10-decanediol di (meth) acrylate and 2-butyl-2-ethyl-1,3-propanediol di (meth) acrylate, The resin particle according to claim 2.   The (B) polyalkylene glycol di (meth) acrylate is polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, poly (ethylene glycol-tetramethylene glycol) di The (meth) acrylate, poly (propylene glycol-tetramethylene glycol) di (meth) acrylate, and polyethylene glycol-polypropylene glycol-polyethylene glycol di (meth) acrylate are at least one selected from the group consisting of: Resin particles.   The resin according to claim 2, wherein the (C) alkylene oxide-modified trimethylolpropane triacrylate is at least one selected from the group consisting of ethylene oxide-modified trimethylolpropane triacrylate and propylene oxide-modified trimethylolpropane triacrylate. particle.   The resin particles according to claim 1, wherein the glass transition temperature (Tg) is 180 ° C. or lower. Resin particle | grains in any one of Claims 1-6 whose deformation rate calculated | required with the following measuring method is 60% or less.
Deformation rate measuring method: A predetermined amount of resin particles are filled into a cylindrical container, and the height h1 is first measured when the temperature is raised to 40 ° C. under a constant load of 0.5 MPa, and then a constant load of 0.5 MPa. The height h2 when the temperature is raised to 100 ° C. is measured below, and the deformation rate (%) is calculated from the obtained height h1 and height h2 based on the following formula.
Deformation rate (%) = [(h1-h2) / (H1-H2)] × 100
Here, H1 is the height when the container is filled with the predetermined amount of resin particles in the hexagonal closest packing (filling ratio: 74%), and the formula: H1 = (total volume of resin particles / 0.74) / The cross-sectional area inside the container,
H2 is the height when the predetermined amount of the resin particles are completely melted in the container, and is determined by the formula: H2 = total volume of resin particles / cross-sectional area inside the container.   The resin particles according to any one of claims 1 to 7, having an average particle diameter of 500 nm or less and a coefficient of variation of 50% or less.   The resin particles according to claim 1, wherein the polyvalent (meth) acrylate is 5% by mass or more based on the total amount of the polymerizable components.   Insulated conductive particles, wherein the resin particles according to any one of claims 1 to 9 are present on at least a part of the surface of the conductive particles.   The insulated conductive particle according to claim 10, wherein the conductive particle has an average particle diameter of 11 μm or less.   An anisotropic conductive material, wherein the insulated conductive particles according to claim 10 or 11 are dispersed in a binder resin.