JP6264731B2 - Conductive resin composition, conductive sheet, electromagnetic wave shielding sheet, manufacturing method thereof, and manufacturing method of conductive fine particles - Google Patents

Description

  The present invention relates to conductive fine particles and a method for producing the same. The present invention also relates to a conductive resin composition containing the conductive fine particles. Furthermore, it is related with an electroconductive sheet and an electromagnetic wave shield sheet provided with the electroconductive layer formed from the said electroconductive resin composition.

  Printed wiring boards are becoming thinner as electronic devices such as mobile phones and digital cameras become smaller, and flexible printed wiring boards are becoming increasingly used. As the printed wiring board, a conductive sheet, an electromagnetic shielding sheet or the like (hereinafter also referred to as “conductive sheet or the like”) is usually used. The conductive sheet or the like is required to have excellent conductive characteristics including stability over time, and the characteristics of the conductive filler contained in the sheet are important.

  As the conductive filler, silver powder is excellent in conductive properties, and thus conductive sheets containing silver powder have been put to practical use. However, the price of silver powder is expensive compared to resins and other raw materials used for conductive sheets and the like, resulting in high costs. In addition, due to the recent increase in silver prices, the price increase of conductive sheets using silver powder has become a serious problem. In order to achieve a reduction in the price of electronic equipment, it is necessary to reduce the usage rate of the conductive filler. However, if the usage rate of the conductive filler is reduced, the desired conductivity cannot be maintained. Face the problem.

  Therefore, various proposals have been made to realize cost reduction while satisfying the conductive characteristics. For example, in patent document 1, the method of improving the adhesive force with respect to a to-be-adhered body is proposed, reducing the quantity of an electroconductive filler by using flaky (scale-like) silver powder as shown in FIG. . Moreover, in patent document 2, the silver coat copper powder which plated silver on the copper surface as electroconductive particle used for these sheets is disclosed. Patent Document 3 discloses a conductive paste in which dendritic silver-coated copper powder and scaly silver powder are mixed as conductive particles.

JP 2011-86930 A JP 2002-75057 A JP 2009-230952 A

  In the market for conductive sheets and the like, development of a sheet having excellent conductive characteristics while reducing the amount of expensive silver powder used is required in order to achieve excellent conductive characteristics and low cost. Furthermore, there is a need for a technique for reducing the thickness of a conductive sheet or the like in order to meet the demand for reduction in size and thickness. When the conductive paste of Patent Document 3 is used as a conductive sheet, there is a problem that it is difficult to reduce the thickness of the sheet because it contains a dendritic silver-coated copper powder. This is because a part of the dendritic silver-coated copper powder may protrude from the conductive layer and break through other layers or damage other layers. In addition, although the example using silver as electroconductive particle was described in the above, the same subject may arise also when using other electroconductive particle. Moreover, although the conductive sheet etc. which are applied to a printed wiring board were described, the same subject may arise in the whole conductive sheet.

  The present invention has been made in view of the above background, and the object of the present invention is that it is possible to reduce costs, have excellent conductive properties, and, for example, when a composition blended with a resin is formed into a sheet shape. It is to provide conductive fine particles that can be made thin.

As a result of extensive studies by the present inventors, it has been found that the problems of the present invention can be solved in the following modes, and the present invention has been completed. That is, the conductive fine particles according to the present invention include a core containing a conductive substance, a coating layer that covers the core and is made of a conductive substance different from the core, and at least a part of which constitutes the outermost layer. And the average value of the circularity degree coefficient obtained from the following formula (1) is 0.15 or more and 0.4 or less, and at least one of notches and branched leaves is formed in the outer edge shape. Yes.

  According to the present invention having the above-described configuration, it is possible to provide conductive fine particles that can be reduced in cost, have excellent conductive characteristics, and can be thinned when, for example, a composition blended with a resin is formed into a sheet shape. There is an excellent effect of being able to.

  As a result of the extensive studies by the present inventors, surprisingly, the average value of the circularity coefficient is in the above range, and the leaf-like conductive fine particles include at least one of notches and branched leaves in the outer edge shape. As a result, it was found that the conductive characteristics were excellent. In addition, when blending dendritic conductive fine particles such as Patent Document 3 and the like, there is a problem that it is difficult to make a thin film, but according to the conductive fine particles according to the present invention, the average value of the circularity coefficient is within the above range. And it turned out that it can be made into a thin film when it kneads | mixes a composition and makes it into a sheet form by setting it as the outer edge shape mentioned above. Further, since different conductive materials are used for the core and the coating layer, the choice of materials can be increased and the cost can be reduced.

It is an electron micrograph which shows an example of the electroconductive fine particles which have a scale leaf or a branched leaf of this invention. It is an electron micrograph of scaly silver powder. It is an electron micrograph of dendritic silver coat copper powder. It is a schematic diagram of the test sample for a connection resistance value measurement.

  Hereinafter, embodiments embodying the present invention will be described. Needless to say, other embodiments are also included in the scope of the present invention as long as they meet the spirit of the present invention. In addition, the numerical range specified using “to” in this specification includes numerical values described before and after “to” as ranges of the lower limit value and the upper limit value. Further, matters other than matters specifically mentioned in the present specification and necessary for the implementation of the present invention can be grasped as design matters for those skilled in the art based on the prior art in this field. Further, the following embodiments are preferably combined with each other.

(Conductive fine particles) The conductive fine particles of the present invention are so-called core-shell type particles, and are composed of a core containing a conductive substance, a core containing the core, and a conductive substance different from the core, and at least one And a coating layer that constitutes the outermost layer. The coating layer only needs to cover at least a part of the nucleus, but in order to obtain more excellent conductive characteristics, a higher coverage is preferable. From the viewpoint of maintaining good conductive properties, the average coverage by the coating layer is preferably 60% or more, more preferably 70% or more, and even more preferably 80% or more. In addition, the average coverage in this specification says the value calculated | required by the method similar to the Example mentioned later.

  The conductive fine particles may be composed only of the nucleus and the coating layer, but may include other layers. For example, layers such as an intermediate layer and a bonding layer that strengthen the bonding between the core and the coating layer may be formed. In addition, the core body, the coating layer, and the other layers may be independently formed of a single type or a plurality of types. Further, in the core body and the coating layer, other substances than the conductive substance may be kneaded within a range not departing from the gist of the present invention.

In the conductive fine particles of the present invention, the average value of the circularity coefficient obtained from the following formula (1) is 0.15 or more and 0.4 or less, and the outer edge has at least one of notches and branched leaves. A plurality are formed.

  The degree of unevenness (undulation degree) of the outer edge of the conductive fine particles can be grasped by the circularity degree coefficient of the above formula (1). The true sphere has a circularity coefficient of 1, and the circularity coefficient decreases as the uneven shape increases. That is, the circularity coefficient is greater than 0 and 1 or less. For the circularity coefficient in this specification, use the analysis software of Mac-View Ver.4 (Mounttech) to read the electron microscopic image (approximately 1000 to 10,000 times) of the conductive fine particles, and use the manual recognition mode. About 20 conductive particles were selected. When selecting the leaf-like or scale-like particles, the whole particle shape in which the particles do not overlap each other can be confirmed, and the particles having an angle at which the plane plate is perpendicular from the observation viewpoint are selected and selected. The particle reference data is a projected area equivalent circle diameter, and the distribution is a volume distribution setting. A circularity coefficient and a circular coefficient are calculated, and 20 average values are obtained. In the above formula (1), the area is the area inside the line forming the outer periphery when projected two-dimensionally as a flat plate surface, and the outer periphery of the conductive fine particles when the flat plate surface is projected two-dimensionally is the peripheral length. Length.

A core shell using an average value of the circularity coefficient obtained from the above formula (1) of not less than 0.15 and not more than 0.4, and at least one of notches and branched leaves formed in the outer edge shape By using the type of conductive fine particles, the cost can be reduced, the conductive characteristics are excellent, and the film can be made thin. The lower limit of the average value of the circle径度coefficients viewpoint et penetration preventing conductive filler into the insulating layer, still more preferably 0.20 or more. Moreover, the circular upper limit of the average value of径度coefficient viewpoint et sheet resistance of the conductive layer, 0. More preferably, it is 3 or less. The average value of the circularity coefficient and the average value of the circular coefficient are preferably about 10 or more particles defined per 1 cm ² .

  In addition, the circularity coefficient of the dendritic conductive fine particles as shown in FIG. 3 is about 0.11 or less, and the circularity coefficient of the scaly conductive fine particles exceeds 0.4, 0.5 It is about the following.

The conductive fine particles of the present invention preferably have an average value of circular coefficients representing circularity obtained from the following formula (2) of 2 or more and 5 or less.
Here, the maximum diameter is the length of the maximum length of the selected particles. By setting the circular coefficient to the above-described range, an effect that the conductivity is further improved can be obtained. From the viewpoint of preventing the conductive filler from penetrating into the insulating layer, the more preferable upper limit of the circular coefficient is 4.5 or less, and more preferably 4.0 or less. Further, from the viewpoint of the sheet resistance of the conductive layer, a more preferable lower limit value of the circular coefficient is 2 or more, and more preferably 2.4 or more. The circular coefficient indicates whether the shape of the entire fine particle is close to a circle (the smaller the value, the closer to the circle). The circular coefficient is a shape factor 3 using the analysis software (Mac-View Ver. 4) used for the circularity coefficient.

  In other words, the conductive fine particles of the present invention are leaf-shaped conductive fine particles having a plurality of at least one of scale leaves and branched leaves. FIG. 1 shows an electron microscope image showing an example of conductive fine particles according to the present invention. In the example of the figure, copper powder is used as the core and silver is used as the coating layer. As shown in the figure, the conductive fine particle has a plurality of cuts and / or branch leaves formed in the outer edge shape. In other words, a plurality of scale leaves, branched leaves, or similar shapes are formed. Hereinafter, the conductive fine particles of the present invention are also referred to as “leaf-shaped conductive fine particles”.

  0.1-2 micrometers is preferable and, as for the thickness of electroconductive fine particles, 0.2-1 micrometer is more preferable. When the thickness is in the range of 0.1 to 2 μm, the conductive sheet can be made thinner while maintaining the conductivity of the conductive sheet. In addition, the said thickness was obtained based on the image expanded about 1000 times-50,000 times with the electron microscope, and "thickness" here is a 10,000 times image of an electron microscope, and is different particle | grains. About 10 to 20 were measured, and the average value was used.

The average particle diameter (D50) of the conductive fine particles is preferably 1 to 100 μm. When the average particle diameter (D50) is in the range of 1 to 100 μm, the conductivity is further improved. Further, for example, when a conductive resin composition is produced by blending with a resin, the solution stability is further improved. it can. The average particle diameter (D50) of the conductive fine particles is more preferably 3 μm or more, and more preferably 50 μm or less. The average particle size (D50) is obtained by measuring each conductive fine particle with a tornado dry powder sample module using a laser diffraction / scattering particle size distribution analyzer LS 13 320 (manufactured by Beckman Coulter). It is the obtained numerical value, and is the average particle diameter of the diameter of the particle size where the integrated value of the particles is 50%. The refractive index was set to 1.6.
In addition, the measurement method of the average particle diameter (D50) when the conductive fine particles are in the form of a conductive sheet is the same as the method for measuring the circularity coefficient, and the conductive fine particles are observed by SEM, and image analysis software is used. In Mac-View Ver.4 (Mounttech), the particle reference data is the projected area circle equivalent diameter, and the distribution is the volume distribution setting, and the average particle diameter (D50) is obtained.

The nucleus functions as a core part of the conductive fine particles. The nucleus is preferably composed of only a conductive material from the viewpoint of improving the conductive properties, but may contain a non-conductive material. The raw material of the nucleus is not particularly limited as long as it satisfies these, and examples thereof include conductive metal, conductive carbon, or conductive resin. Examples of the conductive metal include gold, platinum, copper, nickel, aluminum, iron, or an alloy thereof, but copper is preferable from the viewpoint of cost and conductivity. The conductive carbon is preferably, for example, acetylene black, ketjen black, furnace black, carbon nanotube, carbon nanofiber, graphite, or graphene. In the case of a conductive resin, poly (3,4-ethylenedioxythiophene), polyacetylene, polythiophene, and the like are preferable. It is preferable that the nucleus itself has conductivity.

  The coating layer is made of a conductive material different from the core. Examples of the conductive material that can be used for the coating layer include the materials mentioned in the nucleus. Among them, the use of a material having high conductive characteristics meets the object of the present invention. Specifically, gold, platinum or silver is preferable, and silver is more preferable. In the current technology, conductive materials other than metals, such as conductive resins, have low conductivity. However, if the technology improves and the conductivity improves in the future, conductive resins and the like are also suitable as the coating layer. . From the viewpoint of achieving both cost reduction and improvement in conductive characteristics, it is preferable to use a conductive substance having excellent conductive characteristics in the coating layer and a conductive substance advantageous in cost for the core. A conductive intermediate layer can be provided between the core and the coating layer.

  The coating layer is preferably coated at a ratio of 1 to 40 parts by weight with respect to 100 parts by weight of the core, more preferably 5 to 30 parts by weight, and even more preferably 5 to 20 parts by weight. By using the coating layer in the range of 1 to 40 parts by weight, it is possible to draw out the conductive characteristics while reducing the amount of the conductive material used as the coating layer. For example, when copper is used as the core and silver is used as the coating layer, the price of the conductive fine particles can be effectively reduced while maintaining the conductive characteristics.

  According to the conductive fine particles of the present invention, the conductive characteristics are obtained by setting the average value of the circularity coefficient to the above range and the leaf-shaped conductive fine particles including at least one of notches and branched leaves in the outer edge shape. Was found to be excellent. This is because it increases the irregularities of the particles more than the flaky (scale-like) conductive fine particles with almost no irregularities and undulations, and it has a leaf-like shape that includes at least one of notches and branched leaves in the outer edge shape of the particles. It is considered that the contact point of the conductive fine particles can be increased when the sheet is formed. In addition, the dendritic conductive fine particles have a problem that it is difficult to reduce the thickness, but the conductive fine particles according to the present invention can be easily reduced in thickness. This is because it is flattened rather than dendritic. Further, since different conductive materials are used for the core and the coating layer, the choice of materials can be increased and the cost can be reduced.

  Although the conductive fine particles of the present invention are of the core-shell type, even when particles satisfying the circularity coefficient and the outer edge shape are produced in a single conductive substance, excellent conductive characteristics and Thin film can be achieved. Therefore, if the price of silver or the like is reduced, it is useful even with a single conductive material if the problem of cost reduction can be solved. In addition, when copper is used, there is a problem that the conductive characteristics are lowered due to oxidation. However, if the conductive characteristics can be satisfactorily maintained by the development of an anti-oxidation technique, it is useful even in a single conductive substance.

(Method for Producing Conductive Fine Particles) The method for producing conductive fine particles of the present invention comprises a core containing a conductive substance and a conductive substance which covers the core and is different from the core, and at least partly Is a method for producing conductive fine particles comprising a coating layer constituting the outermost layer. More specifically, a step of preparing a dendritic particle having conductivity and a solid medium for deforming the dendritic particle by colliding with the dendritic particle, and the dendritic particle and the solid medium are sealed in a sealed container. The circularity coefficient obtained from the following mathematical formula (1) is 0.15 or more and 0.4 or less, and at least one of notches and branch leaves is formed in the outer edge shape. And a step of deforming so as to be formed.
Hereinafter, a preferred example will be described in order to embody the method for producing conductive fine particles of the present invention. However, it is not limited by the following manufacturing methods, and various manufacturing methods are possible.

  In the method for producing conductive fine particles of the present invention, a step of preparing a dendritic fine particle having conductivity and a solid medium for deforming the dendritic fine particle by colliding with the dendritic fine particle (step 1). And a step (step 2) of deforming the dendritic fine particles by causing the dendritic fine particles and the solid medium to collide with each other in a closed container.

  In step 1, the dendritic particles are prepared so-called dendritic (dendritic) conductive properties as shown in FIG. As the dendritic particles, non-leaf-like conductive fine particles which are precursors of leaf-like conductive fine particles comprising a nucleus and a coating layer can be suitably used. Moreover, the dendritic particle which consists only of a nucleus may be sufficient. In this case, after the process of step 2, a step of providing a coating layer on the core is performed as step 3.

  The solid medium in Step 1 is caused to collide with the dendritic fine particles so that the circularity coefficient obtained from the mathematical formula (1) is 0.15 or more and 0.4 or less, and the outer edge shape is There is no particular limitation as long as it is possible to obtain conductive fine particles in which at least one of notches and branched leaves is formed.

  The solid medium is preferably a metal such as steel, or a material such as glass, zirconia, alumina, plastic, titania or ceramic. As the sealed container, a known disperser such as a ball mill or a sand mill, or a pulverizer can be used. The shape of the solid medium is preferably a shape with few irregularities such as a spherical shape and an elliptical shape. The size of the solid medium is, for example, about 0.1 to 3 mm. The specific gravity of the solid medium is, for example, about 1.0 to 10.0.

  In step 2, the dendritic fine particles and the solid medium are put into a sealed container, and the dendritic fine particles and the solid medium collide with each other. When the solid medium collides with the dendritic fine particles, the dendritic fine particles are deformed, and for example, leaf-like conductive fine particles as shown in FIG. 1 can be obtained. When producing the conductive fine particles, the solid medium may be collided in the presence of the resin. Thereby, the conductive resin composition mentioned later can be manufactured simultaneously with manufacture of conductive fine particles. The dispersion time and the collision condition for the collision in Step 2 are not particularly limited as long as the conductive fine particles having the above characteristics can be obtained. For example, the dispersion time can be 10 minutes to 60 minutes.

A thickener, a dispersing agent, a heavy metal deactivator, etc. can be used as what is added to electroconductive fine particles when manufacturing electroconductive fine particles. By using a thickener, it is possible to prevent the fine particles from precipitating excessively. Examples of the thickener include silica-based compounds, polycarboxylic acid-based compounds, polyurethane-based compounds, urea-based compounds, and polyamide-based compounds. Dispersibility of conductive fine particles by using a dispersant can be further improved. Examples of the dispersant include an acidic dispersant composed of a carboxylic acid or a phosphate group, a basic dispersant containing an amine group, and a salt type dispersant neutralized with an acid base.

  By using a heavy metal deactivator, even when metal ions are mixed as impurities, the conductivity is hardly inhibited. Examples of heavy metal deactivators include acetylacetone, carboxybenzotriazole compounds, hindered phenol compounds, hydrazine compounds, thiocarbamate compounds, salicylic acid imidazoles and thiadiazole compounds. Moreover, a compound having a unit represented by the chemical formula (1) “hereinafter also referred to as“ compound A ”” is a preferred example.

The amount of compound A added is not limited within a range that does not depart from the spirit of the present invention, but the viscosity stability of the conductive resin composition described later, the temporal stability of the resistance value of the conductive sheet, and the adhesive strength of the electromagnetic shielding sheet From the viewpoint of stability over time, the content is preferably 0.1 parts by weight or more and 30 parts by weight or less with respect to 100 parts by weight of the conductive fine particles. From the viewpoint of improvement of stability over time and cost reduction, 0.5 parts by weight or more and 15 parts by weight or less are more preferable.

Compound A includes various compounds and is not particularly limited. Preferred examples include N-salicyloyl-N′-aldehyderazine, N, N-dibenzal (oxal hydrazide), bis (2-phenoxypropionylhydrazine) isophthalic acid. ), 3- (N-salicyloyl) amino-1,2,4-hydroxyphenyl) propionyl] hydrazine, chemical formula (2) (decamethylenecarboxylic acid disalicyloyl hydrazide) and chemical formula (3) (N, N'- Bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine) can be exemplified. Among these, the compounds of chemical formula (2) and chemical formula (3) are more preferable. By including these, a highly reliable conductive resin composition can be provided. The timing of addition is not limited to the production of the conductive fine particles, and the timing of mixing the conductive fine particles and the resin after the production of the conductive fine particles and the conductive resin composition may be added after the production.

As an example of the conductive fine particles, a production example of silver-coated copper powder will be described below.
[Production Example 1] First, a dendritic silver-coated copper powder obtained by silver plating of copper powder is prepared. The silver-coated copper powder is charged into a sealed container together with a solid medium, the solid medium is collided with the silver-coated copper powder in the sealed container, and the dendritic silver-coated copper powder is transformed into the conductive fine particles of the present invention. When the solid medium collides with the dendritic portion of the silver-coated copper powder, the conductive fine particles having the scale leaf or the branch leaf of the present invention are obtained. In addition, you may throw in resin used for additives, such as a heavy metal deactivator, and / or a conductive resin composition at the timing which throws silver coat copper powder. By adding a conductive resin composition or an additive, it is also possible to manufacture a conductive resin composition, which will be described later, simultaneously with the production of conductive fine particles.

[Production Example 2] First, a dendritic copper powder is prepared. The copper powder is charged into a sealed container together with the solid medium, the solid medium is collided with the copper powder in the sealed container, and the dendritic copper powder is deformed like the conductive fine particles of the present invention. When the solid medium collides with the branch portion of the copper powder, copper powder having scale leaves or branched leaves is obtained. Next, the obtained finely divided copper powder having scale leaves or branched leaves is coated with silver by plating to obtain conductive fine particles having scale leaves or branched leaves of the present invention.

(Conductive resin composition) Next, the conductive resin composition of this invention is demonstrated. The conductive resin composition of the present invention contains the conductive fine particles of the present invention and a resin. The conductive resin composition of the present invention may contain conductive fine particles other than the conductive fine particles of the present invention within a range not departing from the object of the present invention. However, from the viewpoint of improving reliability, the conductive fine particles other than the conductive fine particles of the present invention are preferably, for example, about 3 parts by weight or less with respect to 100 parts by weight of the resin.

  As the resin used in the conductive resin composition, a thermoplastic resin or a curable resin can be used. The curable resin is preferably a thermosetting resin or a photocurable resin.

  As thermoplastic resins, polyolefin resins, vinyl resins, styrene / acrylic resins, diene resins, terpene resins, petroleum resins, cellulose resins, polyamide resins, polyurethane resins, polyester resins, polycarbonate resins, polyimide resins, A fluororesin etc. are mentioned.

The polyolefin resin is preferably a homopolymer or copolymer such as ethylene, propylene, and α-olefin compound. Specific examples include polyethylene ethylene propylene rubber, olefinic thermoplastic elastomer, α-olefin polymer, and the like.
The vinyl resin is preferably a polymer obtained by polymerization of vinyl ester such as vinyl acetate or a copolymer of vinyl ester and olefin compound such as ethylene. Specific examples include ethylene-vinyl acetate copolymer and partially saponified polyvinyl alcohol.

  The styrene / acrylic resin is preferably a homopolymer or copolymer composed of styrene, (meth) acrylonitrile, acrylamides, (meth) acrylic acid esters, maleimides and the like. Specific examples include syndiotactic polystyrene, polyacrylonitrile, acrylic copolymer, ethylene-methyl methacrylate copolymer, and the like.

The diene resin is preferably a homopolymer or copolymer of a conjugated diene compound such as butadiene or isoprene and a hydrogenated product thereof. Specific examples include styrene-butadiene rubber and styrene-isoprene block copolymer.
The terpene resin is preferably a polymer composed of terpenes or a hydrogenated product thereof. Specific examples include terpene resins and hydrogenated terpene resins.

The petroleum resin is preferably a dicyclopentadiene type petroleum resin or a hydrogenated petroleum resin.
The cellulose resin is preferably a cellulose acetate butyrate resin.
The polycarbonate resin is preferably bisphenol A polycarbonate.
The polyimide resin is preferably a thermoplastic polyimide, a polyamideimide resin, or a polyamic acid type polyimide resin.

  Thermosetting resins are functional groups that can be used for crosslinking reactions by heating, such as hydroxyl groups, phenolic hydroxyl groups, methoxymethyl groups, carboxyl groups, amino groups, epoxy groups, oxetanyl groups, oxazoline groups, oxazine groups, aziridine groups, thiols. Any resin having at least one group, isocyanate group, blocked isocyanate group, blocked carboxyl group, silanol group, etc. in one molecule, such as acrylic resin, maleic resin, polybutadiene resin, polyester resin, polyurethane Examples include resins, epoxy resins, oxetane resins, phenoxy resins, polyimide resins, polyamide resins, phenolic resins, alkyd resins, amino resins, polylactic acid resins, oxazoline resins, benzoxazine resins, silicone resins, and fluorine resins. In addition to the above resin, the thermosetting resin in the present invention may contain a so-called “curing agent” such as a resin or a low molecular compound that reacts with the above functional group to form a chemical crosslink as necessary. preferable.

  The photocurable resin may be a resin having at least one unsaturated bond that causes a crosslinking reaction by light, for example, acrylic resin, maleic acid resin, polybutadiene resin, polyester resin, polyurethane resin, epoxy resin. Examples include resins, oxetane resins, phenoxy resins, polyimide resins, polyamide resins, phenolic resins, alkyd resins, amino resins, polylactic acid resins, oxazoline resins, benzoxazine resins, silicone resins, and fluorine resins.

  The conductive resin composition is preferably blended in an amount of 50 to 500 parts by weight, more preferably 100 to 400 parts by weight, with respect to 100 parts by weight of the resin. By blending 50 to 500 parts by weight of the conductive fine particles, the conductivity is further improved and the conductive layer is more easily formed.

  In addition to the conductive fine particles and the resin, the conductive resin composition includes, for example, the dispersant, the silane coupling agent, the rust preventive agent, the copper damage preventive agent in addition to the metal deactivator and the thickener described above. , Reducing agents, antioxidants, pigments, dyes, tackifying resins, plasticizers, ultraviolet absorbers, antifoaming agents, leveling regulators, fillers, flame retardants, and the like.

Producing the conductive resin composition can be obtained by the dendritic silver-coated powder and the resin was charged at the same time, to collide with the solid medium before producing the conductive fine particles as described above. It can also be obtained by mixing with a resin after the production of conductive fine particles. When the resin is mixed with the dispersion, a method of adding the resin while stirring the dispersion with a disperse mat can be exemplified.

(Conductive sheet) The conductive sheet of this invention is equipped with the conductive layer formed from the conductive resin composition of this invention. Although the manufacturing method of an electroconductive sheet is not specifically limited, As an example, the method of coating an electroconductive resin composition on a peelable sheet and forming an electroconductive layer can be illustrated. The conductive sheet may be only a single layer of the conductive layer, but may be a laminate of other functional layers and support layers. The functional layer has insulating properties, thermal conductivity, electromagnetic wave absorption properties, hard coat properties, water vapor barrier properties, oxygen barrier properties, low dielectric constant, high dielectric constant properties, low dielectric loss tangent, high dielectric loss tangent, heat resistance, etc. Layer. In addition, when using the electroconductive sheet of this invention in the printed wiring board field | area, it is preferable that a thermosetting resin is included from a heat resistant viewpoint.

  The conductive sheet of the present invention can be used without limitation for various applications. Preferred examples include an anisotropic conductive sheet, an electrostatic removal sheet, a ground connection sheet, a membrane circuit, a conductive bonding sheet, and a heat conduction. For example, conductive sheets and conductive sheets for jumper circuits.

  Examples of the coating method include a gravure coating method, a kiss coating method, a die coating method, a lip coating method, a comma coating method, a blade method, a roll coating method, a knife coating method, a spray coating method, a bar coating method, a spin coating method, and a dip coating. We can use method

  1-100 micrometers is preferable and, as for the thickness of the conductive layer in a conductive sheet, 3-50 micrometers is more preferable. It becomes easy to make electroconductivity and other physical properties compatible because thickness exists in the range of 1-100 micrometers.

(Electromagnetic wave shielding sheet) The electromagnetic wave shielding sheet of the present invention includes a conductive layer formed from the conductive resin composition of the present invention and an insulating layer, and is intended to shield electromagnetic waves generated from a circuit, for example. Can be used as Although the manufacturing method of an electromagnetic wave shield sheet is not specifically limited, As an example, the method of bonding the electrically conductive layer manufactured by the above-mentioned method and an insulating layer can be illustrated. As the insulating layer, a pre-formed insulating film may be used, or the insulating layer is formed by applying an insulating resin composition to the peelable sheet, and this is attached to the conductive layer with the peelable sheet. You may combine them. Alternatively, the insulating layer may be formed by coating the insulating resin composition directly on the conductive layer.

  The thickness of the insulating layer may vary depending on the application and needs. For example, when used for a flexible printed wiring board, the thickness is set to 2 to 10 μm from the viewpoint of enhancing the shielding effect of the electromagnetic wave shielding sheet while maintaining flexibility. It is preferable. Moreover, it is preferable that the thickness of an insulating layer is a ratio of 50-200 when the thickness of a conductive layer is 100. It becomes easy to balance various physical properties by becoming the said ratio.

  Although the material of an insulating film is not specifically limited, Plastic films, such as polyester, a polycarbonate, a polyimide, polyphenylene sulfide, can also be used. Moreover, the film which shape | molded the insulating resin composition may be sufficient.

  The insulating resin composition contains a resin as an essential component, and it is preferable to use a resin that can be used for the conductive layer. In addition to the resin, the insulating resin composition includes a silane coupling agent, an antioxidant, a pigment, a dye, a dispersant, a tackifier resin, a plasticizer, an ultraviolet absorber, an antifoaming agent, a leveling regulator, and a filling agent. An agent, a flame retardant, etc. can be mix | blended.

  The electromagnetic wave shielding sheet of the present invention can include other layers in addition to the conductive layer and the insulating layer. Other layers include, for example, hard coat properties, thermal conductivity, heat insulation properties, electromagnetic wave absorption properties, water vapor barrier properties, oxygen barrier properties, low dielectric constant, high dielectric constant, low dielectric loss tangent, high dielectric loss tangent, heat resistance, etc. The layer which has is mentioned. In addition, when using the electromagnetic wave shielding sheet of this invention for the printed wiring board field | area, it is preferable that a thermosetting resin is included from a heat resistant viewpoint.

  The electromagnetic wave shielding sheet of the present invention can be used as an electromagnetic wave shielding layer by being attached to a flexible printed circuit board, a rigid printed circuit board, a rigid flexible substrate, etc. and thermocompression bonded. It can also be used by directly pasting the electronic component housing. The printed wiring board incorporating the electromagnetic wave shielding sheet of the present invention is, for example, a mobile phone such as a smartphone, a personal computer, a tablet terminal, LED lighting, organic EL lighting, liquid crystal television, organic EL television, digital camera, digital video camera, automobile, etc. It can be used for automotive parts.

<< Example >>
EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these. The following “parts” and “%” are values based on “parts by weight” and “% by weight”, respectively.

  Table 1 shows non-leaf-like conductive fine particles used as a raw material. As the dendritic silver-coated copper powder of the conductive fine particles 1 to 7, a product manufactured by Mitsui Metal Mining Co., Ltd. was used. Further, as the dendritic copper powder of the conductive fine particles 8, the spherical silver-coated copper powder of the conductive fine particles 9, and the scaly silver powder of the conductive fine particles 11, products made by Fukuda Metal Foil Powder Industry Co., Ltd. were used. Moreover, the product made from Mitsui Metal Mining Co., Ltd. was used for the scale-like silver coat copper powder of the electroconductive fine particles 10. FIG. The average particle diameter (D50) of the conductive fine particles as a raw material was determined with a laser diffraction / scattering particle size distribution analyzer LS 13 320 (manufactured by Beckman Coulter).

<Example A (Production of conductive fine particles)>
100 parts of non-leaf-like conductive fine particles 1 shown in Table 1, 400.0 parts of toluene, 10.0 parts of thickener (AEROSIL R972 manufactured by Nippon Aerosil Co., Ltd.), and heavy metal deactivator (decamethylene carboxylic acid) 1.0 parts of disalicyloyl hydrazide) was weighed and mixed and stirred so as to be uniform. Next, this was introduced into an Eiger mill (“Mini Model M-250 MKII” manufactured by Eiger Japan) together with zirconia beads having a diameter of 0.5 mm, followed by dispersion treatment for 10 minutes. The obtained fine particles were decanted with methyl ethyl ketone five times. Furthermore, the leaf-like electroconductive fine particle of Example A was obtained by drying in 100 degreeC oven. The average particle diameter (D50), thickness, circularity degree coefficient, and circular coefficient of the leaf-like conductive fine particles according to Example A were measured. The average particle diameter (D50) and thickness were determined by the method described above. In addition, the circularity coefficient and the circular coefficient were calculated by the method described above after preparing a sample by the following method. Table 2 shows values of the thickness, average particle diameter (D50), circularity coefficient, circular coefficient, and coverage of the obtained leaf-shaped conductive fine particles.

<Circularity coefficient and circular coefficient> As a measurement sample, a sample using corresponding conductive fine particles was prepared by a method for producing an electromagnetic wave shielding sheet described later. And the sample of 1 cm < ² > was fixed to the cylindrical sample stand for SEM through the electrically conductive adhesive. Specifically, the separator on the conductive layer side of the electromagnetic wave shield sheet was peeled off and fixed to the sample stage so that the conductive layer was the upper layer and the insulating layer was the lower layer. Then, the electromagnetic shielding sheet of the conductive layer was subjected to platinum deposition. After vapor deposition, SEM images of the conductive particles were obtained under the conditions of 1000 times and acceleration voltage of 15 kV, and analyzed by the method described above.

<Coverage> A double-sided pressure-sensitive adhesive tape was affixed to a dedicated stand, each metal particle powder was dropped on the double-sided pressure-sensitive adhesive tape, and then excess powder was blown off with air. Then, five different points were measured with an X-ray photoelectron spectrometer (ESCA AXIS-HS, manufactured by Shimadzu Corporation). And the average value of mass concentration% of a coating layer (silver) calculated from the peak area of a coating layer (silver) and a nucleus (copper) with analysis software (made by Kratos) was made into the silver coverage.

<Examples B to K, Comparative Example δ (Production of conductive fine particles)>
Conductive fine particles were produced in the same manner as in Example A, except that the raw material of non-leaf conductive fine particles and the dispersion treatment time using Eiger mill were changed as described in Table 2.

<Examples 1-20, Comparative Examples 1-4, Reference Example 1 (Production of conductive resin composition)>
The raw materials shown in Table 3 were charged in a container, and stirred for 5 minutes with a disper to obtain conductive resin compositions of Examples 1 to 20, Comparative Examples 1 to 4, and Reference Example 1.

  The base resin urethane is a polyurethane resin (Toyochem), the amide is a polyamideimide resin (Toyochem), and the polyester is a condensed polyester (Toyochem) and an addition polyester (Toyochem). Using. 10 parts of a curing agent (aziridine compound) was used with respect to 100 parts by weight of the base resin.

<Manufacture of the electroconductive sheet of Example 1>
The conductive resin composition of Example 1 was coated on a polyethylene terephthalate peelable sheet using a bar coater so that the dry thickness was 5 μm, and dried in an electric oven at 100 ° C. for 2 minutes to form a conductive layer. A conductive sheet C1 having was obtained.

<Manufacture of the electromagnetic wave shielding sheet of Example 1>
A thermosetting urethane resin (manufactured by Toyochem Co., Ltd.) is coated on a polyethylene terephthalate release sheet using a bar coater to a dry thickness of 5 μm, and then dried in an electric oven at 100 ° C. for 2 minutes for insulation. A layer was obtained. The conductive layer of the conductive sheet C1 and the insulating layer were overlapped, and an electromagnetic wave shield sheet E1 was obtained by thermocompression bonding under conditions of 80 ° C. and 2 MPa.

<Manufacture of the conductive sheet of Examples 2-20, Comparative Examples 1-4, and Reference Example 1>
Conductive sheets C2 to C20 were obtained in the same manner as in Example 1, except that the conductive resin composition of Examples 2 to 20 was used instead of the conductive resin composition of Example 1. Moreover, it replaced with the conductive resin composition of Example 1, and except having used the conductive resin composition of Comparative Examples 1-4 and Reference Example 1, conductive sheet C21-C25 was carried out by the method similar to Example 1. Obtained.

<Manufacture of electromagnetic wave shield sheets of Examples 2 to 20, Comparative Examples 1 to 4 and Reference Example 1>
Instead of the conductive sheet C 1 except for using the conductive sheet as described in Table 4, to obtain an electromagnetic wave shielding sheet E2~E25 by performing in the same manner as in Example 1.
Electromagnetic wave shield sheets E2 to E20 were obtained in the same manner as in Example 1, except that the conductive resin composition of Examples 2 to 20 was used instead of the conductive resin composition of Example 1. Moreover, it replaced with the electroconductive resin composition of Example 1, and except using the electroconductive resin composition of Comparative Examples 1-4 and the reference example 1 by the method similar to Example 1, electromagnetic shielding sheet E21-E25 was carried out. Obtained.

<Measurement of connection resistance>
Prepare conductive sheet 10 cut to 25mm length and 25mm width, and fix it to the end of stainless steel plate 11 with width 25mm, length 100mm, thickness 0.5mm, and temporarily press bonded under conditions of 80 ° C and 2MPa. did. Thereafter, the peelable sheet was peeled off, and the stainless steel plates 12 having the same size were stacked in the same manner as described above, and then temporarily bonded by thermocompression bonding under the conditions of 80 ° C. and 2 MPa. This was thermocompression bonded for 30 minutes under the conditions of 150 ° C. and 2 MPa to obtain a test piece for connection resistance measurement shown in FIG. Using this test piece, the connection resistance value is measured by bringing the BSP probe of “Lorester GP” manufactured by Mitsubishi Chemical Analytech into contact with the B side of the stainless steel plate 11 and the A side of the stainless steel plate 12 as shown in FIG. did. The evaluation criteria are as follows.
A: Less than 1.0 × 10 ⁻³ B: 1.0 × 10 ⁻³ or more, less than 1.0 × 10 ⁻² C: 1.0 × 10 ⁻² or more, less than 1.0 × 10 ⁻¹ D: 1.0 × 10 ^-1 or more

<Measurement of surface resistance value>
The surface resistance value of the conductive layer of the obtained electromagnetic wave shielding sheet was measured using a four-point probe of “Loresta GP” manufactured by Mitsubishi Chemical Analytech. The evaluation criteria are as follows.
A: Less than 1.0 B: 1.0 or more and less than 10.0 C: 10.0 or more and less than 50.0 D: 50.0 or more

On the other hand, the surface resistance value of the insulating layer of the electromagnetic wave shielding sheet was measured using a ring probe URS of “HIRESTA UP” manufactured by Mitsubishi Chemical Analytech. The evaluation criteria are as follows.
A: 1 × 10 ⁷ or more B: less than 1 × 10 ⁷ , 1 × 10 ⁶ or more C: less than 1 × 10 ⁶ , 1 × 10 ⁴ or more D: less than 1 × 10 ⁴

<Measurement of adhesive strength>
An electromagnetic wave shielding sheet having a width of 25 mm and a length of 70 mm was prepared. By peeling off the peelable film that comes into contact with the conductive layer, and pressing the polyimide film (“Kapton 200EN” manufactured by Toray DuPont) with a thickness of 50 μm on the exposed conductive layer under the conditions of 150 ° C., 1.0 MPa, and 30 min. The conductive layer and the insulating layer were cured. In order to reinforce the electromagnetic shielding sheet for measurement, the release film that contacts the 50 μm-thick insulating layer is removed, and the exposed insulating layer is a polyimide film using an adhesive sheet using a polyurethane polyurea adhesive. (“Kapton 200EN” manufactured by Toray DuPont) was pressure-bonded under the conditions of 150 ° C., 1 MPa, and 30 min. Through these steps, a test piece of “polyimide film / electromagnetic wave shield sheet / adhesive sheet / polyimide film” was obtained. The adhesive strength of the test piece was measured by peeling the interface between the conductive layer and the polyimide film under an atmosphere of 23 ° C. and a relative humidity of 50% at a pulling speed of 50 mm / min and a peeling angle of 90 °.
A: 8N / 25mm or more B: Less than 8N / 25mm, 6N / 25mm or more C: Less than 6N / 25mm, 3N / 25mm or more D: Less than 3N / 25mm

[Appendix]
The present specification also discloses the invention of the technical idea shown below, which is grasped from the above-described embodiment.
(Appendix 1)
A leaf-shaped conductive fine particle having a plurality of scale leaves or branched leaves, which is formed by coating a conductive core with a conductive substance different from the core.
(Appendix 2)
A step in which a solid medium collides with a dendritic fine particle coated with silver on a conductive core, whereby the dendritic conductive fine particle is deformed to obtain a plurality of leaf-like fine particles having scale leaves or branch leaves A method for producing leaf-shaped conductive fine particles, comprising:
(Appendix 3)
Conductive fine particles having a circularity coefficient determined from the following mathematical formula (1) of 0.15 or more and 0.4 or less, and at least one of notches and branched leaves is formed in the outer edge shape.
(Appendix 4)
A nucleus containing a conductive material;
Covering the core body, comprising a conductive material different from the core body, comprising at least a coating layer constituting an outermost layer,
Conductive fine particles having a circularity coefficient determined from the following mathematical formula (1) of 0.15 or more and 0.4 or less, and at least one of notches and branched leaves is formed in the outer edge shape.
(Appendix 5)
The conductive fine particles according to supplementary note 4, wherein the coating layer is 1 part by weight or more and 40 parts by weight or less with respect to 100 parts by weight of the core.
(Appendix 6)
The conductive fine particles according to supplementary note 4 or 5, wherein the thickness is 0.1 μm or more and 2 μm or less.
(Appendix 7)
The conductive fine particles according to any one of supplementary notes 4 to 6, wherein the coating layer is silver.
(Appendix 8)
A conductive resin composition comprising the conductive fine particles according to any one of supplementary notes 4 to 7 and a resin.
(Appendix 9)
The conductive resin composition according to any one of supplementary notes 4 to 8, wherein a compound having a unit represented by the following chemical formula (1) is blended.
(Appendix 10)
The conductive resin composition according to appendix 9, wherein the compound having a unit represented by the chemical formula (1) includes at least one of the following chemical formula (2) and the following chemical formula (3).
(Appendix 11)
The conductive sheet provided with the conductive layer formed from the conductive resin composition in any one of appendix 8-10.
(Appendix 12)
The electromagnetic wave shield sheet provided with the conductive layer formed from the conductive resin composition in any one of Additional remark 8-10, and the insulating layer.
(Appendix 13)
A nucleus containing a conductive material;
A method for producing conductive fine particles, comprising a coating layer that coats the core and is made of a conductive material different from the core, and at least a part of which forms a coating layer.
Preparing a dendritic particle having conductivity and a solid medium for deforming the dendritic particle by colliding with the dendritic particle;
By causing the dendritic microparticles and the solid medium to collide in a closed container, the circularity coefficient obtained from the following mathematical formula (1) is 0.15 or more and 0.4 or less, and And a step of deforming the outer edge so that at least one of notches and branched leaves is formed in plural.
(Appendix 14)
The method for producing conductive fine particles according to appendix 13, wherein the dendritic fine particles are obtained by coating the dendritic core with the coating layer.
(Appendix 15)
14. The method for producing conductive fine particles according to appendix 13, wherein the dendritic fine particles include the dendritic core, and the dendritic fine particles are coated with the coating layer after the dendritic fine particles are deformed.

  This application claims the priority on the basis of Japanese application Japanese Patent Application No. 2012-49680 for which it applied on March 6, 2011, and takes in those the indications of all here.

  The conductive fine particles of the present invention can be used for various applications as a filler that requires conductive properties. Preferably, the conductive resin composition containing the conductive fine particles of the present invention and a resin can be used for various applications. For example, a conductive layer can be formed from a conductive resin composition and used as a conductive sheet or an electromagnetic wave shielding sheet. The conductive sheet can be used for the purpose of electrical connection between circuits, for example. The conductive sheet and electromagnetic wave shield sheet of the present invention are suitable for, for example, a flexible printed wiring board that is repeatedly bent, a rigid printed wiring board, a metal plate, a flexible connector, and the like.

10 Sample 11, 12 Stainless plate

Claims (24)

A conductive fine particle comprising: a core containing a conductive substance made of metal ; and a coating layer that covers the core and is made of a conductive substance different from the core, and at least a part of which constitutes the outermost layer. ,
Including resin,
The conductive fine particles are leaf-like particles obtained by thinning dendritic fine particles, and protrusions and cuts that leave traces of dendritic fine particle dendrites are recognized across the leaf-like outer edge, and the following formula ( 1) the average value of the circle径度coefficient obtained from 0.15 or more, 0.3 der Ru conductive resin composition or less.
However, the perimeter length is obtained by reading the electron microscopic image of the conductive fine particles, and extracting the conductive fine particles that can be confirmed as a whole with the leaf-like plane of the conductive fine particles being in a direction perpendicular to the observation viewpoint. Means the length of the outer periphery when the extracted conductive fine particles are projected two-dimensionally, and the area is a wide area defined by the outer periphery when the extracted conductive fine particles are projected two-dimensionally. Say it.   The conductive resin composition according to claim 1, wherein the coating layer is 1 part by weight or more and 40 parts by weight or less with respect to 100 parts by weight of the core. The conductive resin composition according to claim 1, wherein the conductive fine particles have a thickness of 0.1 μm or more and 2 μm or less.   The conductive resin composition according to claim 1, wherein the coating layer is silver.   5. The conductive resin composition according to claim 1, wherein the conductive fine particles have an average value of a circular coefficient obtained from the following mathematical formula (2) of 2 or more and 5 or less.
However, the area reads the electron microscopic image of the conductive fine particles, the leaf-like plane of the conductive fine particles is in a direction perpendicular to the observation viewpoint, and the conductive fine particles that can be confirmed as a whole are extracted, The width of the region defined by the outer periphery when the extracted conductive fine particles are two-dimensionally projected is referred to, and the maximum diameter is the maximum length of the extracted conductive fine particles.   The conductive resin composition according to any one of claims 1 to 5, comprising 50 to 500 parts by weight of the conductive fine particles with respect to 100 parts by weight of the resin. Furthermore, the conductive resin composition of any one of Claims 1-6 in which the compound which has a unit represented by following Chemical formula (1) is mix | blended.
The conductive resin composition according to claim 7 , wherein the compound having a unit represented by the chemical formula (1) includes at least one of the following chemical formula (2) and the following chemical formula (3).
Conductive sheet having a conductive layer obtained by forming a conductive resin composition according to any one of claims 1-8.   The connection resistance value of the conductive layer is 1.0 × 10 ^-1 Less than Ω / 25mm
(However, for the connection resistance value, a sample having a conductive layer of 5 μm in thickness, 25 mm in length and 25 mm in width is prepared, and the entire main surface of the sample is 25 mm in width, 100 mm in length, and 0.5 mm in thickness. It is placed opposite to the end of the main surface of one stainless steel plate and temporarily bonded by thermocompression bonding under conditions of 80 ° C. and 2 MPa,
  Further, the entire surface of the other main surface of the sample is opposed to the end of the main surface of the second stainless steel plate having a width of 25 mm, a length of 100 mm, and a thickness of 0.5 mm, and in the region not facing the sample. One stainless steel plate and the second stainless steel plate are arranged so as to be most separated from each other, and temporarily bonded by thermocompression bonding under the conditions of 80 ° C. and 2 MPa,
  For the test piece obtained by thermocompression bonding the first stainless steel plate and the second stainless steel plate sandwiched with the sample at 150 ° C. and 2 MPa for 30 minutes,
  The first stainless steel plate and the second stainless steel plate are the values measured by bringing a probe of a resistivity meter into contact with each main surface in the same direction where the first stainless steel plate and the second stainless steel plate are not opposed to each other)
The conductive sheet according to claim 9. An electromagnetic wave shielding sheet comprising a conductive layer formed from the conductive resin composition according to any one of claims 1 to 8, and an insulating layer. A conductive fine particle comprising: a nucleus containing a conductive material made of metal ; and a coating layer that covers the nucleus and is made of a conductive material different from the nucleus, and at least a part of which constitutes the outermost layer. A manufacturing method comprising:
Preparing a dendritic particle having conductivity and a solid medium for deforming the dendritic particle by colliding with the dendritic particle;
A step of causing the dendritic microparticles and the solid medium to collide with each other in a closed container, thereby transforming the dendritic microparticles into a thinned leaf shape,
Protrusions and cuts that leave traces of the dendritic fine particles are recognized across the leaf-shaped outer edge formed by the deformation, and the average value of the circularity coefficient obtained from the following formula (1) is 0.15 or more 0.3 der Ru method for producing conductive fine particles or less.
However, the perimeter length is obtained by reading the electron microscopic image of the conductive fine particles, and extracting the conductive fine particles that can be confirmed as a whole with the leaf-like plane of the conductive fine particles being in a direction perpendicular to the observation viewpoint. Means the length of the outer periphery when the extracted conductive fine particles are projected two-dimensionally, and the area is a wide area defined by the outer periphery when the extracted conductive fine particles are projected two-dimensionally. Say it.   The manufacturing method of the electroconductive fine particles of Claim 12 which makes the said coating layer 1 to 40 weight part with respect to 100 weight part of said nuclei.   The method for producing conductive fine particles according to claim 12 or 13, wherein a thickness of the conductive fine particles is 0.1 µm or more and 2 µm or less.   The method for producing conductive fine particles according to claim 12, wherein the coating layer is silver.   The average value of the circular coefficient calculated | required from following Numerical formula (2) is 2-5, The manufacturing method of the electroconductive fine particles of any one of Claims 12-15.
However, the area reads the electron microscopic image of the conductive fine particles, the leaf-like plane of the conductive fine particles is in a direction perpendicular to the observation viewpoint, and the conductive fine particles that can be confirmed as a whole are extracted, The width of the region defined by the outer periphery when the extracted conductive fine particles are two-dimensionally projected is referred to, and the maximum diameter is the maximum length of the extracted conductive fine particles.   The method for producing conductive fine particles according to any one of claims 12 to 16, wherein an average coverage of the coating layer with respect to the surface of the core is 60% or more. The method for producing conductive fine particles according to any one of claims 12 to 17 , wherein the dendritic fine particles are obtained by covering the dendritic core with the coating layer. The dendritic particles are dendritic the nucleus, conductive fine particles according to item 1 or one of claims 12 to 17 to be coated on the dendritic particles said coating layer after deforming the dendritic particles Manufacturing method.   Conductive fine particles obtained by the method for producing conductive fine particles according to any one of claims 12 to 19,
  The manufacturing method of the conductive resin composition which mix | blends resin.   Furthermore, the manufacturing method of the conductive resin composition of Claim 20 which mix | blends the compound which has a unit represented by following Chemical formula (1).
  The method for producing a conductive resin composition according to claim 21, wherein the compound having a unit represented by the chemical formula (1) includes at least one of the following chemical formula (2) and the following chemical formula (3).
  Forming a conductive resin composition containing conductive fine particles and a resin;
  A method for producing a conductive sheet comprising a step of forming a conductive layer using the conductive resin composition,
  The said conductive resin composition is a manufacturing method of the conductive sheet formed with the manufacturing method of the conductive resin composition of any one of Claims 20-22.   Forming a conductive resin composition containing conductive fine particles and a resin;
  A method for producing an electromagnetic wave shielding sheet comprising a step of forming a conductive layer on the insulating layer using the conductive resin composition,
  The said conductive resin composition is a manufacturing method of the electromagnetic wave shield sheet formed with the manufacturing method of the conductive resin composition of any one of Claims 20-22.