WO2015115139A1 - Copper powder - Google Patents

Copper powder Download PDF

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Publication number
WO2015115139A1
WO2015115139A1 PCT/JP2015/050261 JP2015050261W WO2015115139A1 WO 2015115139 A1 WO2015115139 A1 WO 2015115139A1 JP 2015050261 W JP2015050261 W JP 2015050261W WO 2015115139 A1 WO2015115139 A1 WO 2015115139A1
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Prior art keywords
copper powder
particles
major axis
powder particles
branches
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PCT/JP2015/050261
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French (fr)
Japanese (ja)
Inventor
宏幸 森中
晃祐 織田
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三井金属鉱業株式会社
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Priority to JP2015523333A priority Critical patent/JP5876971B2/en
Publication of WO2015115139A1 publication Critical patent/WO2015115139A1/en

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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C9/00—Alloys based on copper
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/06—Metallic powder characterised by the shape of the particles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/05—Metallic powder characterised by the size or surface area of the particles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • B22F9/16—Making metallic powder or suspensions thereof using chemical processes
    • B22F9/18—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds
    • B22F9/24—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from liquid metal compounds, e.g. solutions

Definitions

  • the present invention relates to a copper powder that can be suitably used as a conductive filler contained in a conductive paste or a conductive film.
  • a conductive paste is a fluid composition in which a conductive filler is dispersed in a vehicle composed of a resin binder and a solvent.
  • a conductive filler is dispersed in a vehicle composed of a resin binder and a solvent.
  • Dendritic copper powder particles obtained by the electrolytic method have more contact points between the particles than spherical copper powder particles, so when used as a conductive filler in a conductive paste, the amount of conductive filler is reduced. Even in this case, there is an advantage that the conductive characteristics can be improved.
  • a copper powder for a conductive paint that can be soldered it is a rod-like shape obtained by crushing a dendritic copper powder having a particle shape
  • a copper powder characterized in that the amount (JIS K5101) is 20 ml / 100 g or less, the maximum particle size is 44 ⁇ m or less, the average particle size is 10 ⁇ m or less, and the hydrogen reduction weight loss is 0.5% or less is disclosed. .
  • Patent Document 3 and Patent Document 4 disclose electrolytic copper powder particles having a dendritic shape as a heat pipe constituent raw material.
  • Patent Document 5 describes that a method for electrolysis by adding chlorine to an electrolytic solution is known as a production method for adjusting the dendrite form of the electrolytic copper powder with respect to the method for producing the dendritic electrolytic copper powder. Yes.
  • Patent Document 6 is provided with a single main shaft, and a plurality of branches obliquely branch from the main shaft to form a dendritic shape that grows two-dimensionally or three-dimensionally, and the thickness of the main shaft a Is a dendrite-like copper powder comprising a dendrite-like copper powder particle having a longest branch length b of 0.6 ⁇ m to 10.0 ⁇ m among the branches extending from the main axis of 0.3 ⁇ m to 5.0 ⁇ m Is disclosed.
  • Japanese Patent Laid-Open No. 06-158103 Japanese Patent Laid-Open No. 2000-80408 JP 2008-122030 A JP 2009-047383 A Japanese Patent Laid-Open No. 1-224784 JP 2013-019034 A
  • the dendritic copper powder has the advantage that, as described above, the number of contact points between the particles is larger than that of the spherical copper powder particles, so that the conductivity can be ensured even if the amount is small. ing.
  • the dendrite-like copper powder has a problem that it is difficult to reduce the thickness of the conductive film and the conductive film compared to the spherical copper powder particles because of its shape.
  • the present invention is intended to provide a new copper powder that can sufficiently thin a conductive film and a conductive film, and that can ensure electrical conductivity in a small amount even with fine particles. is there.
  • the concentration of chlorine contained in the copper powder is 5 wtppm to 150 wtppm
  • the volume cumulative particle size D50 measured by a laser diffraction / scattering particle size distribution analyzer is 0.5 ⁇ m to 5.0 ⁇ m
  • the scanning type When observing copper powder particles using an electron microscope (SEM), it has a single main axis, and a plurality of branches obliquely branch from the main axis and grow in two or three dimensions.
  • a dendritic copper powder particle (hereinafter referred to as “special dendritic copper powder”) having a branching number (the number of branches / main shaft major axis L) of 3.0 to 20.0 / ⁇ m with respect to the major axis L of the major axis. It proposes a copper powder characterized in that 80% by number or more of all the copper powder particles are also referred to as “particles”).
  • the copper powder proposed by the present invention is a copper powder in which fine and special dendrite-like particles occupy 80% by number or more, a conductive film and a conductive film are sufficiently obtained compared to conventional dendrite-like copper powder. It is possible to reduce the thickness, and the conductivity can be ensured with a small amount as compared with the conventional fine spherical copper powder.
  • the copper powder (referred to as “the present copper powder”) according to the present embodiment is a copper powder containing copper powder particles (referred to as “the present copper powder particles”) exhibiting a predetermined special dendrite shape.
  • “dendrite-like copper powder particles” are, when observed with an electron microscope (500 to 20000 times), provided with one main axis as shown in FIG. It is a copper powder particle having a shape in which branches branch vertically or obliquely and grow two-dimensionally or three-dimensionally.
  • the main axis refers to a rod-like portion that is a group from which a plurality of branches are branched.
  • the present copper powder particles particularly exhibit a dendrite shape having the following predetermined characteristics. preferable.
  • the number of branch branches with respect to the major axis length L indicates the number of dendrite branches, and is preferably 3.0 to 20.0 / ⁇ m. If the number of branches / major axis major axis L is 3.0 / ⁇ m or more, even if the major axis L of the main axis is short, the number of branch branches is sufficiently large, so that sufficient contact between the conductive fillers can be secured. It is possible to ensure conduction with a small amount.
  • the number of branches / major axis L is 20.0 / ⁇ m or less, the number of branch branches will not be too large, so that the fluidity of the copper powder can be prevented from being deteriorated.
  • the number of branches / major axis major axis L of the copper powder particles is preferably 3.0 to 20.0 / ⁇ m, and more preferably 4.0 / ⁇ m or more or 19.0 / ⁇ m. In the following, it is more preferable that the number is 5.0 / ⁇ m or more or 18.0 / ⁇ m or less.
  • it is more preferably 6.0 lines / ⁇ m or more or 18.0 lines / ⁇ m or less, and particularly preferably 6.0 lines / ⁇ m or more or 16.0 lines / ⁇ m or less.
  • the number of branch branches is the number that can be confirmed by a photograph, and the number of hidden branch branches is an ignored number.
  • the major axis L of the main shaft is preferably 0.5 ⁇ m to 5.0 ⁇ m. If the major axis L of the main shaft is 0.5 ⁇ m or more, sufficient conductivity can be ensured, and if it is 5.0 ⁇ m or less, the thickness of the conductive film or conductive film can be sufficiently reduced. From such a viewpoint, the major axis L of the main axis of the copper powder particles is preferably 0.5 ⁇ m to 5.0 ⁇ m, more preferably 1.0 ⁇ m or more and 4.5 ⁇ m or less, and more preferably 1.5 ⁇ m or more or 4.0 ⁇ m. Hereinafter, among them, it is 3.5 ⁇ m or less, more preferably 3.0 ⁇ m or less, and more preferably 2.0 ⁇ m or less.
  • the special dendrite-like copper powder particles as described above when observed with an electron microscope (500 to 20,000 times), special particles can be used even if particles of other shapes are mixed. The same effect as the copper powder consisting only of dendritic copper powder particles can be obtained. Therefore, from this point of view, when the present copper powder is observed with an electron microscope (500 to 20,000 times), the shape as described above, that is, the special dendrite-like copper powder particles are 80% by number of the total copper powder particles. As long as it occupies 90% by number or more, more preferably 95% by number or more, copper powder particles of other shapes may be included.
  • chlorine is added to the electrolytic solution under predetermined electrolysis conditions using an electrolysis apparatus equipped with an electrode having a predetermined surface roughness, as described later. It is preferable to add and perform electrolysis. However, it is not limited to this method.
  • the average number of branches (number of branches / major axis length L) with respect to the major axis length L of the particles recognized as dendritic particles is 4.0 to 30. It is preferably 0.0 / ⁇ m, more preferably 5.0 / ⁇ m or more, or 28.0 / ⁇ m or less, and more preferably 6.0 / ⁇ m or more or 25.0 / ⁇ m or less. It is more preferable that the number is 0 / ⁇ m or more or 23.0 / ⁇ m or less.
  • 50 or more dendritic particles may be arbitrarily measured and the average value may be obtained.
  • the copper powder preferably has a concentration of chlorine contained in the copper powder (also referred to as “contained chlorine concentration”), that is, a concentration of chlorine contained in the inside of the particles rather than on the surface of the copper powder particles is 5 wtppm to 150 wtppm. Among them, 10 wtppm or more or 140 wtppm or less, more preferably 20 wtppm or more or 130 wtppm or less, more preferably 30 wtppm or more or 100 wtppm or less, and particularly preferably 30 wtppm or more or 80 wtppm or less. If the chlorine concentration of the copper powder is 150 wtppm or less, the contact resistance can be kept low.
  • the content chlorine concentration of this copper powder may be less than 5 wtppm, about 5 wtppm is a detection limit of a content chlorine concentration.
  • the D50 of the present copper powder that is, the volume cumulative particle size D50 measured by a laser diffraction / scattering particle size distribution analyzer is preferably 0.5 ⁇ m to 5.0 ⁇ m. If D50 of this copper powder is 0.5 ⁇ m or more, it is possible to ensure a dendrite-like shape necessary for ensuring sufficient conductivity, and if it is 5.0 ⁇ m or less, a conductive film or The thickness of the conductive film can be sufficiently reduced. From this point of view, the D50 of the present copper powder is preferably 0.5 ⁇ m to 5.0 ⁇ m, more preferably 1.0 ⁇ m or more and 4.5 ⁇ m or less, particularly 1.5 ⁇ m or more or 4.0 ⁇ m or less.
  • D50 of the present copper powder for example, to reduce D50, for example, it is preferable to shorten the electrolysis time, that is, to scrape off the copper powder deposited on the electrode plate within a short time. .
  • the specific surface area (SSA) of the present copper powder measured by the BET single point method is preferably 1.20 to 4.00 m 2 / g.
  • SSA specific surface area
  • the specific surface area as measured by single point method BET of the copper powder is 1.20 ⁇ 4.00m 2 / g at and even good properly, inter alia 1.50 m 2 / g or more or 3.50 m 2 / g or less, particularly 3.00 m 2 / g or less among them, still more preferably 2.00 m 2 / g or more or 3.00 m 2 / g or less among them.
  • the copper powder preferably has a specific surface area (SSA) ratio of D50 to 0.3 to 2.0 m 2 / (g ⁇ ⁇ m). If the SSA / D50 is 0.3 m 2 / (g ⁇ ⁇ m) or more, the branch branch is developed, so that the contact between the conductive fillers is sufficient, and if it is 2.0 or less, the branch is thin. The shape does not collapse when roll kneading or filtering as a conductive filler.
  • SSA specific surface area
  • the SSA / D50 of the present copper powder is preferably 0.3 to 2.0 m 2 / (g ⁇ ⁇ m), and above all, 0.4 m 2 / (g ⁇ ⁇ m) or more, or 1.8 m 2 / ( g ⁇ ⁇ m) or less, more preferably 0.5 m 2 / (g ⁇ ⁇ m) or more or 1.6 m 2 / (g ⁇ ⁇ m) or less. In particular, it is more preferably 0.7 m 2 / (g ⁇ ⁇ m) or more or 1.5 m 2 / (g ⁇ ⁇ m) or less.
  • the tap bulk density of the copper powder is preferably 0.3 to 1.5 g / cm 3 . Since the copper powder has a dendritic particle shape and branch branches are densely formed, the tap bulk density is relatively low, being 1.5 g / cm 3 or less. On the other hand, if the tap bulk density is 0.5 g / cm 3 or more, the amount of oil absorption can be reduced, and high conductivity can be obtained during paste preparation. From this viewpoint, it is preferred tapped bulk density of the copper powder is 0.3 ⁇ 1.5g / cm 3, among them 0.50 g / cm 3 or more, or 1.2 g / cm 3 or less, among the 0. 60 g / cm 3 or more, or 1.10 g / cm 3 or less, and even more preferably in particular 0.70 g / cm 3 or more, or 1.00 g / cm 3 or less therein.
  • the oil absorption (JISK5101) of the present copper powder is preferably 30 to 100 mL / 100 g. If the oil absorption of copper powder (JISK5101) is 30 mL / 100 g or more, it can be said that more oil can be absorbed with less copper powder than ordinary copper powder. The function can be exhibited with the conductive material. From this point of view, the oil absorption (JISK5101) of the present copper powder is preferably 30 to 100 mL / 100 g, particularly 40 mL / 100 g or more or 90 mL / 100 g or less, and particularly 50 mL / 100 g or more or 80 mL / 100 g or less. Is more preferable.
  • This copper powder can be manufactured by a predetermined electrolytic method.
  • an electrolysis method for example, an anode and a cathode are immersed in a sulfuric acid electrolytic solution containing copper ions, and a direct current is passed through the electrolyte to conduct electrolysis.
  • a method of scraping and collecting by an electric method, washing with water, drying, and producing electrolytic copper powder through a sieving step and the like as necessary can be exemplified. At this time, it is preferable to add a small amount of chlorine to the electrolytic solution and scrape it off within a short time after deposition using an electrode having a predetermined surface roughness in order to produce the copper powder.
  • the chlorine concentration of the electrolytic solution is preferably adjusted to 3 to 200 mg / L, more preferably 5 mg / L or more or 150 mg / L or less.
  • a Ti electrode or the like is preferably used for the electrode, particularly the cathode. However, it is not limited to Ti.
  • the surface roughness Rz of the electrode, particularly the cathode is preferably 2.0 ⁇ m or less, and particularly preferably 1.0 ⁇ m or less. It is considered that the surface roughness Rz of the cathode is preferably as small as possible. However, in practice, it is considered practical that it is 0.001 ⁇ m or more, and 0.1 ⁇ m or more in consideration of economy. When a normal copper plate having a high surface roughness is used, the copper powder particles are concentrated on the convex portions of the surface irregularities, and thus it is difficult to obtain the present copper powder.
  • the size of the electrolytic cell, the number of electrodes, the distance between the electrodes, and the circulation amount of the electrolyte solution are adjusted so that the copper ion concentration in the electrolyte solution near the electrodes is always increased.
  • the electrolytic cell size is 2 m 3 to 10 m 3
  • the number of electrodes is 10 to 40
  • the distance between the electrodes is 5 cm to 50 cm
  • the liquid temperature is 20 to 60 ° C., preferably 30 ° C. or more and 50 ° C.
  • the surface of the electrolytic copper powder particles may be subjected to an oxidation resistance treatment using an organic material as necessary to form an organic material layer on the surface of the copper powder particles. It is not always necessary to form the organic layer, but it is more preferable that the organic layer is formed in consideration of the change over time due to oxidation of the copper powder particle surface.
  • the organic substance used for this oxidation resistance treatment is not particularly limited, and examples thereof include glue, gelatin, organic fatty acid, and a coupling agent.
  • the oxidation-resistant treatment method that is, the organic layer forming method may be a dry method or a wet method.
  • a method of mixing an organic substance and copper powder particles with a V-type mixer or the like in the case of a wet method, a method of adding an organic substance to a water-copper powder particle slurry and adsorbing it on the surface can be mentioned.
  • a method of adhering an organic substance to the copper powder surface by mixing an aqueous solution containing a copper powder cake and a desired organic substance with an organic solvent after washing with water after electrolytic copper powder deposition is a preferred example.
  • this copper powder is used as a conductive filler of a conductive film or a conductive film, the conductive film or the conductive film can be made sufficiently thin, and conductivity can be ensured in a small amount. Therefore, this copper powder is particularly suitable as a conductive filler for conductive pastes and conductive films.
  • the present copper powder is mixed with a binder and a solvent, and further, if necessary, a curing agent, a coupling agent, a corrosion inhibitor, etc. Can be produced. It is also possible to mix this copper powder and copper powder of another shape or size to produce a conductive paste.
  • examples of the binder include liquid epoxy resins, phenol resins, unsaturated polyester resins, and the like, but are not limited thereto.
  • examples of the solvent include terpineol, ethyl carbitol, carbitol acetate, butyl cellosolve and the like.
  • examples of the curing agent include 2-ethyl-4-methylimidazole.
  • examples of the corrosion inhibitor include benzothiazole and benzimidazole.
  • the conductive paste can be used to form various electrical circuits by forming a circuit pattern on the substrate.
  • a printed wiring board an electric circuit of various electronic components, external electrodes, and the like by applying or printing on a fired substrate or an unfired substrate, heating, pressurizing and baking as necessary.
  • the present copper powder particles as a core material, a part or all of these surfaces can be covered with a different conductive material such as gold, silver, nickel, tin and the like.
  • a different conductive material such as gold, silver, nickel, tin and the like.
  • the circulating electrolyte temperature is 40 ° C.
  • the Cu concentration is 15 g / L
  • the sulfuric acid (H 2 SO 4 ) concentration is 150 g / L
  • the chlorine concentration is 50 mg / L
  • the current density is 100 A / m 2.
  • the electrolysis was carried out for 30 minutes.
  • the major axis L of the main shaft was 0.5 to 5.0 ⁇ m, and the number of branches / main shaft major axis L was 3. It was confirmed that the copper powder particles having a dendritic shape of 0 to 20.0 particles / ⁇ m (special dendritic copper powder particles) accounted for 80% by number or more of the total copper powder particles.
  • Example 2 In Example 1, an electrolytic copper powder (sample) was obtained in the same manner as in Example 1 except that the Cu concentration was 10 g / L and the chlorine concentration was 150 mg / L.
  • the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 0.5 to 5.0 ⁇ m, and the number of branches / main shaft major axis L was 3. It was confirmed that the copper powder particles having a dendritic shape of 0 to 20.0 particles / ⁇ m (special dendritic copper powder particles) accounted for 80% by number or more of the total copper powder particles.
  • Example 3 In Example 1, an electrolytic copper powder (sample) was obtained in the same manner as in Example 1 except that the Cu concentration was 20 g / L and the current density was 200 A / m 2 .
  • the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 1.0 to 4.5 ⁇ m, and the number of branches / main shaft major axis L was 3. It was confirmed that the copper powder particles having a dendritic shape of 0 to 20.0 particles / ⁇ m (special dendritic copper powder particles) accounted for 80% by number or more of the total copper powder particles.
  • Example 4 In Example 1, an electrolytic copper powder (sample) was obtained in the same manner as in Example 1 except that the chlorine concentration was 150 mg / L, the sulfuric acid concentration was 100 g / L, and the current density was 200 A / m 2 .
  • the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 1.5 to 4.0 ⁇ m, and the number of branches / main shaft major axis L was 3. It was confirmed that copper powder particles having a dendritic shape of 5 to 19.0 particles / ⁇ m (special dendritic copper powder particles) accounted for 80% by number or more of the total copper powder particles.
  • Example 5 an electrolytic copper powder (sample) was obtained in the same manner as in Example 1 except that the chlorine concentration was 200 mg / L and the sulfuric acid concentration was 200 g / L.
  • the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 1.0 to 5.0 ⁇ m, and the number of branches / main shaft major axis L was 6. It was confirmed that the copper powder particles having a dendrite shape of 0 to 18.0 particles / ⁇ m (special dendritic copper powder particles) accounted for 80% by number or more of the total copper powder particles.
  • Example 6 An electrolytic copper powder (sample) was obtained in the same manner as in Example 1 except that the electrolyte temperature was 30 ° C., the chlorine concentration was 200 mg / L, and the sulfuric acid concentration was 200 g / L.
  • the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 1.5 to 4.0 ⁇ m, and the number of branches / main shaft major axis L was 3. It was confirmed that copper powder particles having a dendritic shape of 5 to 19.0 particles / ⁇ m (special dendritic copper powder particles) accounted for 80% by number or more of the total copper powder particles.
  • Example 7 an electrolytic copper powder (sample) was obtained in the same manner as in Example 1 except that the electrolyte temperature was 50 ° C., the chlorine concentration was 15 mg / L, and the Cu concentration was 10 g / L.
  • the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 0.5 to 5.0 ⁇ m, and the number of branches / main shaft major axis L was 3. It was confirmed that the copper powder particles having a dendritic shape of 0 to 20.0 particles / ⁇ m (special dendritic copper powder particles) accounted for 80% by number or more of the total copper powder particles.
  • Example 8 In Example 1, an electrolytic copper powder (sample) was prepared in the same manner as in Example 1 except that the chlorine concentration was 100 mg / L, the Cu concentration was 10 g / L, the current density was 200 A / m 2 , and the sulfuric acid concentration was 200 g / L. Obtained.
  • the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 0.5 to 5.0 ⁇ m, and the number of branches / main shaft major axis L was 3. It was confirmed that the copper powder particles having a dendritic shape of 0 to 20.0 particles / ⁇ m (special dendritic copper powder particles) accounted for 80% by number or more of the total copper powder particles.
  • Example 9 In Example 1, an electrolytic copper powder (sample) was obtained in the same manner as in Example 1 except that the chlorine concentration was 200 mg / L, the Cu concentration was 3 g / L, and the sulfuric acid concentration was 200 g / L.
  • the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 0.5 to 5.0 ⁇ m, and the number of branches / main shaft major axis L was 3. It was confirmed that the copper powder particles having a dendritic shape of 0 to 20.0 particles / ⁇ m (special dendritic copper powder particles) accounted for 80% by number or more of the total copper powder particles.
  • Example 10 In Example 1, an electrolytic copper powder (sample) was obtained in the same manner as in Example 1 except that the chlorine concentration was 100 mg / L, the Cu concentration was 2 g / L, and the current density was 200 A / m 2 .
  • the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 0.5 to 5.0 ⁇ m, and the number of branches / main shaft major axis L was 3. It was confirmed that the copper powder particles having a dendritic shape of 0 to 20.0 particles / ⁇ m (special dendritic copper powder particles) accounted for 80% by number or more of the total copper powder particles.
  • Example 1 In Example 1, it manufactured like Example 1 except having made chlorine concentration into 1000 mg / L, Cu density into 10 g / L, current density to 50 A / m ⁇ 2 >, and sulfuric acid concentration into 100 g / L.
  • the copper deposited on the cathode surface was mechanically scraped and collected, and then washed to obtain a hydrous copper powder cake equivalent to 1 kg of copper powder.
  • the cake was washed with pure water to remove impurities, 1 L of an industrial gelatin (Nitta Gelatin Co., Ltd.) 10 g / L aqueous solution was added and stirred, and then 80 80 under reduced pressure (1 ⁇ 10 ⁇ 3 Pa).
  • Example 2 An electrolytic copper powder (sample) was prepared in the same manner as in Example 1 except that the chlorine concentration was 500 mg / L, the Cu concentration was 10 g / L, the current density was 200 A / m 2 , and the sulfuric acid concentration was 100 g / L. Obtained. When the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), it was confirmed that most of the copper powder particles had a needle shape or a rod shape.
  • SEM scanning electron microscope
  • Example 3 an electrolytic copper powder (sample) was prepared in the same manner as in Example 1 except that the chlorine concentration was 400 mg / L, the Cu concentration was 10 g / L, the current density was 200 A / m 2 , and the sulfuric acid concentration was 100 g / L. Obtained. When the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), it was confirmed that most of the copper powder particles had a needle shape or a rod shape.
  • SEM scanning electron microscope
  • Example 4 an electrolytic copper powder (sample) was prepared in the same manner as in Example 1 except that the chlorine concentration was 300 mg / L, the Cu concentration was 5 g / L, the current density was 50 A / m 2 , and the sulfuric acid concentration was 50 g / L. Obtained.
  • the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 0.5 to 5.0 ⁇ m, and the number of branches / main shaft major axis L was 3.
  • the proportion of 0 to 20.0 dendritic copper powder particles (special dendritic copper powder particles) in the total copper powder particles was less than 80% by number.
  • Example 5 the electrolytic copper powder (sample) was obtained in the same manner as in Example 1 except that the surface roughness Rz of the Ti cathode plate was 3.0 ⁇ m, the chlorine concentration was 150 mg / L, and the Cu concentration was 5 g / L. Obtained.
  • the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 0.5 to 5.0 ⁇ m, and the number of branches / main shaft major axis L was 3.
  • the proportion of 0 to 20.0 dendritic copper powder particles (special dendritic copper powder particles) in the total copper powder particles was less than 80% by number.
  • Example 6 In Example 1, except that the surface roughness Rz of the Ti cathode plate was 5.5 ⁇ m, the chlorine concentration was 100 mg / L, the current density was 50 A / m 2 , and the sulfuric acid concentration was 100 g / L, the same as in Example 1.
  • An electrolytic copper powder (sample) was obtained. When the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 0.5 to 5.0 ⁇ m, and the number of branches / main shaft major axis L was 3.
  • the proportion of 0 to 20.0 dendritic copper powder particles (special dendritic copper powder particles) in the total copper powder particles was less than 80% by number.
  • Example 7 Commercially available atomized copper powder (Atomized copper powder manufactured by Mitsui Kinzoku Co., non-dendritic, D50: 3.4 ⁇ m) was obtained, evaluated in the same manner as in Example 1, and the results are shown in the table.
  • the atomized copper powder means a copper powder produced by an atomizing method, not an electrolytic method.
  • the copper powders (samples) obtained in the examples and comparative examples were observed with a scanning electron microscope (2,000 times), and the shapes of arbitrary 500 particles were respectively observed.
  • a ”), the length b (the“ branch length b ”) of the longest branch among the branches extending from the main axis, the number of branch branches with respect to the major axis length L (the number of branches / the major axis length L), and the average are shown in Table 1.
  • the average value is an average value of particles recognized as dendritic copper powder particles.
  • the number ratio of dendritic copper powder particles (referred to as “special dendritic copper powder particles”) having the number of branches / major axis major axis L of 3.0 to 20.0 / ⁇ m in the total copper powder particles Is shown in Table 1 as “number ratio of special dendrite in all particles”. Further, the number ratio of the special dendrite-like copper powder particles having a branch number / major axis major axis L of 3.0 to 20.0 / ⁇ m in the dendrite-like copper powder particles is expressed as “the number of special dendrites in the dendrite. The number ratio is shown in Table 1. In the observation of the particle shape, a small amount of copper powder (sample) was attached to the carbon tape so that the particles did not overlap each other.
  • ⁇ Particle size measurement> Take a small amount of copper powder (sample) obtained in Examples and Comparative Examples in a small amount of beaker, add a few drops of 3% Triton X solution (manufactured by Kanto Chemical Co., Ltd.) A sample for measurement was prepared by adding 50 mL of the Sant 41 solution (San Nopco) and then dispersing for 2 minutes using an ultrasonic disperser TIP ⁇ 20 (manufactured by Nippon Seiki Seisakusho). This sample for measurement was measured for volume accumulation standard D50 using a laser diffraction / scattering particle size distribution measuring device MT3300 (manufactured by Nikkiso), and is shown in Table 1.
  • SSA specific surface area
  • TD Tap bulk density
  • a paste was prepared by mixing 55 g of the copper powder (sample) obtained in Examples and Comparative Examples, 20 g of an epoxy resin (EPICLON 850 manufactured by DIC) as a binder, and 25 g of toluene as an organic solvent. Next, the paste was applied on a PET substrate so that the width was 200 mm and the gap was 15 ⁇ m with a bar coater, and then dried in an atmospheric hot air drying oven at 120 ° C. for 10 minutes. A membrane was obtained. The obtained coating film was observed with an optical microscope (magnification 100 times) to evaluate the appearance of the coating film.
  • a mode in which the coating film failure is less than 5 in an area of a coating length of 100 mm is “ ⁇ (good) ”, 5 to 10 is“ ⁇ (pass) ”, and 11 or more is“ ⁇ (defective) ”.
  • ⁇ (good) a mode in which the coating film failure is less than 5 in an area of a coating length of 100 mm
  • 5 to 10 is“ ⁇ (pass) ”
  • 11 or more is“ ⁇ (defective) ”.
  • the dust resistance value was measured using a dust resistance measurement system (Mitsubishi Chemical PD-41) and a resistivity meter (Mitsubishi Chemical MCP-T600). 5 g of the sample was put into the probe cylinder, and the probe unit was set on PD-41. The resistance value when a load of 10 kN was applied by a hydraulic jack was measured using the MCP-T600 by the 4-probe method. And the volume resistivity was computed from the measured resistance value and sample thickness.
  • a paste was prepared by mixing an appropriate amount of the copper powder (sample) obtained in Examples and Comparative Examples, 20 g of an epoxy resin (EPICLON 850 manufactured by DIC) as a binder, and 25 g of toluene as an organic solvent. Next, the paste was applied on a PET substrate so that the width was 200 mm and the gap was 15 ⁇ m with a bar coater, and then dried in an atmospheric hot air drying oven at 120 ° C. for 10 minutes. A membrane was obtained. The resulting coating film was measured for sheet resistance by a four-probe method using a resistivity meter (Mitsubishi Chemical MCP-T600).
  • the sheet resistance value and the filling amount of the copper powder (sample) at the time of measurement were measured, and the filling amount (weight) of the copper powder obtained by the measurement was determined as the total weight of the copper powder and the epoxy resin (100 wt. %), And the value was shown in the table as “powder filling amount (wt%) when measuring sheet resistance powder”.
  • the filling amount (weight) of the copper powder obtained by the measurement was determined as the total weight of the copper powder and the epoxy resin (100 wt. %), And the value was shown in the table as “powder filling amount (wt%) when measuring sheet resistance powder”.
  • the copper powders obtained in Examples 1 to 10 the powders were sufficiently in contact with each other to measure the resistance value.
  • the resistance was The value was too high to be overranged and could not be measured (shown as “-” in the table).
  • the major axis L of each of the copper powders is 0.5 to 5.0 ⁇ m.
  • Number of branches / major axis major axis L is 3.0 to 20.0 / ⁇ m, especially 4.0 / ⁇ m or more or 19.0 / ⁇ m or less, and more preferably 5.0 / ⁇ m or more or 18.0 / Confirmed that the copper powder particles having a dendrite shape of ⁇ m or less, particularly 6.0 particles / ⁇ m or more or 18.0 particles / ⁇ m or less occupy 80% by number or more of the total copper powder particles. did it.
  • the concentration of chlorine is 5 wtppm to 150 wtppm
  • D50 is 0.5 ⁇ m to 5.0 ⁇ m
  • the number of branch branches with respect to the major axis L of the main shaft (branches Dendritic copper powder particles (special dendritic copper powder particles) whose number / major axis major axis L) is 3.0 to 20.0 / ⁇ m account for 80% or more of all copper powder particles. Then, it can be considered that the conductive film and the conductive film can be made sufficiently thin, and the conductive characteristics can be obtained with a small amount.

Abstract

Provided is a new copper powder from which a conductive film having a sufficiently reduced thickness can be formed and which, although fine, can ensure conductivity even when used in a small amount. The copper powder is characterized by having a chlorine concentration of 5-150 wt ppm and a volume-cumulative particle diameter D50 of 0.5-5.0 μm, and having a dendritic shape which comprises one trunk and a plurality of branches obliquely branching off from the trunk and two-dimensionally or three-dimensionally grown. The copper powder is further characterized in that the copper powder particles each having a dendritic shape in which the ratio of the number of branches to the major-axis length L of the trunk (number of branches/trunk major-axis length L (μm)) is 3.0-20.0 account for 80% by number or more of all the copper powder particles.

Description

銅粉Copper powder
　本発明は、導電性ペーストや導電性フィルムなどに含有される導電フィラーとして好適に用いることができる銅粉に関する。 The present invention relates to a copper powder that can be suitably used as a conductive filler contained in a conductive paste or a conductive film.
　導電性ペーストは、樹脂系バインダと溶媒からなるビヒクル中に導電フィラーを分散させた流動性組成物であり、電気回路の形成や、セラミックコンデンサの外部電極の形成、各種導電性フィルムの形成などに広く用いられている。 A conductive paste is a fluid composition in which a conductive filler is dispersed in a vehicle composed of a resin binder and a solvent. For conductive circuit formation, formation of external electrodes of ceramic capacitors, formation of various conductive films, etc. Widely used.
　この種の導電性ペーストに含有される導電フィラーとして、従来は、銀粉が多用されてきた。しかし、銅粉を用いた方が安価である上、マイグレーションが生じ難く、耐ハンダ性にも優れているため、銅粉を用いた導電性ペーストが汎用化されつつある。 Conventionally, silver powder has been frequently used as a conductive filler contained in this type of conductive paste. However, the use of copper powder is cheaper, migration is less likely to occur, and the solder resistance is excellent. Therefore, conductive pastes using copper powder are being widely used.
　電解法によって得られるデンドライト状の銅粉粒子は、球状の銅粉粒子に比べて、粒子同士の接点の数が多くなるため、導電性ペーストの導電フィラーとして用いた場合、導電フィラーの量を少なくしても導電特性を高めることができるという利点を有している。 Dendritic copper powder particles obtained by the electrolytic method have more contact points between the particles than spherical copper powder particles, so when used as a conductive filler in a conductive paste, the amount of conductive filler is reduced. Even in this case, there is an advantage that the conductive characteristics can be improved.
　このようなデンドライト状の銅粉に関しては、例えば特許文献１において、半田付け可能な導電性塗料用銅粉として、粒子形状の樹枝状銅粉を解砕してえられた棒状であって、吸油量（ＪＩＳ　Ｋ５１０１）が２０ｍｌ／１００ｇ以下、最大粒径が４４μｍ以下でかつその平均粒径が１０μｍ以下、水素還元減量が０．５％以下であることを特徴とする銅粉が開示されている。 With regard to such a dendrite-like copper powder, for example, in Patent Document 1, as a copper powder for a conductive paint that can be soldered, it is a rod-like shape obtained by crushing a dendritic copper powder having a particle shape, A copper powder characterized in that the amount (JIS K5101) is 20 ml / 100 g or less, the maximum particle size is 44 μm or less, the average particle size is 10 μm or less, and the hydrogen reduction weight loss is 0.5% or less is disclosed. .
　特許文献２には、平均粒径２０～３５μｍ、嵩密度０．５～０．８ｇ／ｃｍ3の樹枝状電解銅粉に油脂を添加、混合し、該電解銅粉表面に油脂を被覆した後、衝突板方式ジェットミルによって粉砕、微粉化することを特徴とする微小銅粉の製造方法が開示されている。 In Patent Document 2, fats and oils are added to and mixed with dendritic electrolytic copper powder having an average particle size of 20 to 35 μm and bulk density of 0.5 to 0.8 g / cm 3 , and the surface of the electrolytic copper powder is coated with the fats and oils. A method for producing fine copper powder, characterized in that it is pulverized and pulverized by a collision plate type jet mill, is disclosed.
　特許文献３及び特許文献４には、ヒートパイプ構成原料として、デンドライト状を呈する電解銅粉粒子が開示されている。 Patent Document 3 and Patent Document 4 disclose electrolytic copper powder particles having a dendritic shape as a heat pipe constituent raw material.
　特許文献５には、デンドライト状電解銅粉の製造方法に関し、電解銅粉のデンドライト形態を整えるための製法として、電解液に塩素を添加して電解する方法が知られている旨が記載されている。 Patent Document 5 describes that a method for electrolysis by adding chlorine to an electrolytic solution is known as a production method for adjusting the dendrite form of the electrolytic copper powder with respect to the method for producing the dendritic electrolytic copper powder. Yes.
　特許文献６には、一本の主軸を備えており、該主軸から複数の枝が斜めに分岐して、二次元的或いは三次元的に成長したデンドライト状を呈し、かつ、主軸の太さａが０．３μｍ～５．０μｍであり、主軸から伸びた枝の中で最も長い枝の長さｂが０．６μｍ～１０．０μｍであるデンドライト状を呈する銅粉粒子を含有するデンドライト状銅粉が開示されている。 Patent Document 6 is provided with a single main shaft, and a plurality of branches obliquely branch from the main shaft to form a dendritic shape that grows two-dimensionally or three-dimensionally, and the thickness of the main shaft a Is a dendrite-like copper powder comprising a dendrite-like copper powder particle having a longest branch length b of 0.6 μm to 10.0 μm among the branches extending from the main axis of 0.3 μm to 5.0 μm Is disclosed.
特開平０６－１５８１０３号公報Japanese Patent Laid-Open No. 06-158103 特開２０００－８０４０８号公報Japanese Patent Laid-Open No. 2000-80408 特開２００８－１２２０３０号公報JP 2008-122030 A 特開２００９－０４７３８３号公報JP 2009-047383 A 特開平１－２４７５８４号公報Japanese Patent Laid-Open No. 1-224784 特開２０１３－０１９０３４号公報JP 2013-019034 A
　導電性ペーストや導電性フィルムにおいて、ファイン化及び薄型化が進められており、そのような用途には、従来は、導電フィラーとして、球状で且つ粒径の小さな微粒銅粉が通常用いられてきた。ところが、球状の微粒銅粉は、含有量を多くしないと、導通性を得られないという問題点を抱えていた。 In conductive pastes and conductive films, refinement and thinning have been promoted, and in such applications, fine copper powder having a spherical shape and a small particle size has been conventionally used as a conductive filler. . However, the spherical fine copper powder has a problem that the electrical conductivity cannot be obtained unless the content is increased.
　これに対し、デンドライト状銅粉は、上述のように、球状の銅粉粒子に比べて、粒子同士の接点の数が多くなるため、量が少なくても導通性を確保できるという利点を有している。しかしその反面、デンドライト状銅粉は、その形状ゆえに、球状の銅粉粒子に比べて、導電性フィルムや導電膜の厚さを薄くすることが難しいという課題を抱えていた。 On the other hand, the dendritic copper powder has the advantage that, as described above, the number of contact points between the particles is larger than that of the spherical copper powder particles, so that the conductivity can be ensured even if the amount is small. ing. On the other hand, the dendrite-like copper powder has a problem that it is difficult to reduce the thickness of the conductive film and the conductive film compared to the spherical copper powder particles because of its shape.
　そこで本発明は、導電性フィルムや導電膜を十分に薄くすることができ、しかも、微粒であっても少ない量で導通性を確保することができる、新たな銅粉を提供せんとするものである。 Therefore, the present invention is intended to provide a new copper powder that can sufficiently thin a conductive film and a conductive film, and that can ensure electrical conductivity in a small amount even with fine particles. is there.
　本発明は、銅粉中に含まれる塩素の濃度が５ｗｔｐｐｍ～１５０ｗｔｐｐｍであり、レーザー回折散乱式粒度分布測定装置によって測定される体積累積粒径Ｄ５０が０．５μｍ～５．０μｍであり、走査型電子顕微鏡（ＳＥＭ）を用いて銅粉粒子を観察した際、一本の主軸を備えており、該主軸から複数の枝が斜めに分岐して、二次元的或いは三次元的に成長したデンドライト状を呈し、かつ、主軸の長径Ｌに対する分岐枝の本数（枝本数／主軸長径Ｌ）が３．０～２０．０本／μｍであるデンドライト状を呈する銅粉粒子（以下「特殊デンドライト状銅粉粒子」とも称する）が、全銅粉粒子のうちの８０個数％以上を占めることを特徴とする銅粉を提案するものである。 In the present invention, the concentration of chlorine contained in the copper powder is 5 wtppm to 150 wtppm, the volume cumulative particle size D50 measured by a laser diffraction / scattering particle size distribution analyzer is 0.5 μm to 5.0 μm, and the scanning type When observing copper powder particles using an electron microscope (SEM), it has a single main axis, and a plurality of branches obliquely branch from the main axis and grow in two or three dimensions. And a dendritic copper powder particle (hereinafter referred to as “special dendritic copper powder”) having a branching number (the number of branches / main shaft major axis L) of 3.0 to 20.0 / μm with respect to the major axis L of the major axis. It proposes a copper powder characterized in that 80% by number or more of all the copper powder particles are also referred to as “particles”).
　本発明が提案する銅粉は、微粒で且つ特殊なデンドライト状の粒子が８０個数％以上を占める銅粉であるため、従来のデンドライト状銅粉に比べて、導電性フィルムや導電膜を十分に薄くすることができ、しかも、従来の微粒球状銅粉に比べて、少ない量で導通性を確保することができる。 Since the copper powder proposed by the present invention is a copper powder in which fine and special dendrite-like particles occupy 80% by number or more, a conductive film and a conductive film are sufficiently obtained compared to conventional dendrite-like copper powder. It is possible to reduce the thickness, and the conductivity can be ensured with a small amount as compared with the conventional fine spherical copper powder.
デンドライト状銅粉粒子の粒子形状を説明するためのモデル図である。It is a model figure for demonstrating the particle shape of a dendrite-like copper powder particle. 実施例５で得られた銅粉の電子顕微鏡写真である。6 is an electron micrograph of the copper powder obtained in Example 5. 実施例６で得られた銅粉の電子顕微鏡写真である。4 is an electron micrograph of the copper powder obtained in Example 6. 比較例４で得られた銅粉の電子顕微鏡写真である。4 is an electron micrograph of the copper powder obtained in Comparative Example 4. 比較例５で得られた銅粉の電子顕微鏡写真である。6 is an electron micrograph of the copper powder obtained in Comparative Example 5.
　以下、本発明の実施形態について詳述する。但し、本発明の範囲が以下の実施形態に限定されるものではない。 Hereinafter, embodiments of the present invention will be described in detail. However, the scope of the present invention is not limited to the following embodiments.
＜本銅粉の特徴＞
　本実施形態に係る銅粉（「本銅粉」と称する）は、所定の特殊なデンドライト状を呈する銅粉粒子（「本銅粉粒子」と称する）を含有する銅粉である。 <Features of this copper powder>
The copper powder (referred to as “the present copper powder”) according to the present embodiment is a copper powder containing copper powder particles (referred to as “the present copper powder particles”) exhibiting a predetermined special dendrite shape.
　本銅粉において「デンドライト状銅粉粒子」とは、電子顕微鏡（５００～２００００倍）で観察した際に、図１に示されるように、一本の主軸を備えており、該主軸から複数の枝が垂直若しくは斜めに分岐して、二次元的或いは三次元的に成長した形状を呈する銅粉粒子である。この際、主軸とは、複数の枝がそこから分岐している基となる棒状部分を示す。 In the present copper powder, “dendrite-like copper powder particles” are, when observed with an electron microscope (500 to 20000 times), provided with one main axis as shown in FIG. It is a copper powder particle having a shape in which branches branch vertically or obliquely and grow two-dimensionally or three-dimensionally. In this case, the main axis refers to a rod-like portion that is a group from which a plurality of branches are branched.
　中でも、本銅粉粒子を、走査型電子顕微鏡（ＳＥＭ）を用いて銅粉粒子を観察した際（５００～２０，０００倍）、次のような所定の特徴を有するデンドライト状を呈するのが特に好ましい。 In particular, when the copper powder particles are observed with a scanning electron microscope (SEM) (500 to 20,000 times), the present copper powder particles particularly exhibit a dendrite shape having the following predetermined characteristics. preferable.
　・主軸の長径Ｌに対する分岐枝の本数（枝本数／主軸長径Ｌ）は、デンドライトの枝の多さを示しており、３．０～２０．０本／μｍであるのが好ましい。枝本数／主軸長径Ｌが３．０本／μｍ以上であれば、主軸の長径Ｌが短くても、分岐枝の本数が十分に多いため、導電フィラー同士の接点を十分に確保することができ、少ない量で導通の確保が可能となる。他方、枝本数／長径Ｌが２０．０本／μｍ以下であれば、分岐枝の数が多過ぎることがないため、銅粉の流動性が劣るのを防ぐことができる。
　このような観点から、本銅粉粒子の枝本数／主軸長径Ｌは、３．０～２０．０本／μｍであるのが好ましく、中でも４．０本／μｍ以上或いは１９．０本／μｍ以下、その中でも５．０本／μｍ以上或いは１８．０本／μｍ以下であるのがさらに好ましい。その中でも特に６．０本／μｍ以上或いは１８．０本／μｍ以下、その中でも特に６．０本／μｍ以上或いは１６．０本／μｍ以下であることがさらに好ましい。
　なお、分岐枝の本数は、写真で確認できる本数であり、隠れた分岐枝の本数は無視した本数である。 The number of branch branches with respect to the major axis length L (number of branches / main axis major axis length L) indicates the number of dendrite branches, and is preferably 3.0 to 20.0 / μm. If the number of branches / major axis major axis L is 3.0 / μm or more, even if the major axis L of the main axis is short, the number of branch branches is sufficiently large, so that sufficient contact between the conductive fillers can be secured. It is possible to ensure conduction with a small amount. On the other hand, if the number of branches / major axis L is 20.0 / μm or less, the number of branch branches will not be too large, so that the fluidity of the copper powder can be prevented from being deteriorated.
From such a viewpoint, the number of branches / major axis major axis L of the copper powder particles is preferably 3.0 to 20.0 / μm, and more preferably 4.0 / μm or more or 19.0 / μm. In the following, it is more preferable that the number is 5.0 / μm or more or 18.0 / μm or less. Among these, in particular, it is more preferably 6.0 lines / μm or more or 18.0 lines / μm or less, and particularly preferably 6.0 lines / μm or more or 16.0 lines / μm or less.
Note that the number of branch branches is the number that can be confirmed by a photograph, and the number of hidden branch branches is an ignored number.
　・主軸の長径Ｌは０．５μｍ～５．０μｍであるのが好ましい。主軸の長径Ｌが０．５μｍ以上であれば十分な導電性を確保でき、５．０μｍ以下であれば、導電性フィルムや導電膜の厚さを十分に薄くすることができる。
　このような観点から、本銅粉粒子の主軸の長径Ｌは０．５μｍ～５．０μｍであるのが好ましく、中でも１．０μｍ以上或いは４．５μｍ以下、その中でも１．５μｍ以上或いは４．０μｍ以下、その中でも３．５μｍ以下、その中でも３．０μｍ以下、その中でも２．０μｍ以下であるのがさらに好ましい。 The major axis L of the main shaft is preferably 0.5 μm to 5.0 μm. If the major axis L of the main shaft is 0.5 μm or more, sufficient conductivity can be ensured, and if it is 5.0 μm or less, the thickness of the conductive film or conductive film can be sufficiently reduced.
From such a viewpoint, the major axis L of the main axis of the copper powder particles is preferably 0.5 μm to 5.0 μm, more preferably 1.0 μm or more and 4.5 μm or less, and more preferably 1.5 μm or more or 4.0 μm. Hereinafter, among them, it is 3.5 μm or less, more preferably 3.0 μm or less, and more preferably 2.0 μm or less.
　但し、電子顕微鏡（５００～２０，０００倍）で観察した際、多くの粒子が上記の如き特殊デンドライト状銅粉粒子で占められていれば、それ以外の形状の粒子が混じっていても、特殊デンドライト状銅粉粒子のみからなる銅粉と同様の効果を得ることができる。よって、かかる観点から、本銅粉は、電子顕微鏡（５００～２０，０００倍）で観察した際、上記のような形状、すなわち特殊デンドライト状銅粉粒子が全銅粉粒子のうちの８０個数％以上、好ましくは９０個数％以上、さらに好ましくは９５個数％以上を占めていれば、他の形状の銅粉粒子が含まれていてもよい。 However, when many particles are occupied by the special dendrite-like copper powder particles as described above when observed with an electron microscope (500 to 20,000 times), special particles can be used even if particles of other shapes are mixed. The same effect as the copper powder consisting only of dendritic copper powder particles can be obtained. Therefore, from this point of view, when the present copper powder is observed with an electron microscope (500 to 20,000 times), the shape as described above, that is, the special dendrite-like copper powder particles are 80% by number of the total copper powder particles. As long as it occupies 90% by number or more, more preferably 95% by number or more, copper powder particles of other shapes may be included.
　上記のような特殊デンドライト状銅粉粒子を作製するためには、後述するように、所定の表面粗度の電極を備えた電解装置を使用して所定の電解条件下で、電解液に塩素を添加して電解を行うことが好ましい。但し、この方法に限定するものではない。 In order to produce the special dendrite-like copper powder particles as described above, chlorine is added to the electrolytic solution under predetermined electrolysis conditions using an electrolysis apparatus equipped with an electrode having a predetermined surface roughness, as described later. It is preferable to add and perform electrolysis. However, it is not limited to this method.
　また、本銅粉を構成する銅粉粒子のうち、デンドライト状粒子と認められる粒子における、主軸の長径Ｌに対する分岐枝の本数（枝本数／主軸長径Ｌ）の平均値は、４．０～３０．０本／μｍであるのが好ましく、中でも５．０本／μｍ以上或いは２８．０本／μｍ以下、その中でも６．０本／μｍ以上或いは２５．０本／μｍ以下、その中でも８．０本／μｍ以上或いは２３．０本／μｍ以であるのがさらに好ましい。
　この際、平均値の求め方としては、本銅粉を構成する銅粉粒子のうち、任意に５０個以上のデンドライト状粒子を計測して、その平均値を求めればよい。 Of the copper powder particles constituting the present copper powder, the average number of branches (number of branches / major axis length L) with respect to the major axis length L of the particles recognized as dendritic particles is 4.0 to 30. It is preferably 0.0 / μm, more preferably 5.0 / μm or more, or 28.0 / μm or less, and more preferably 6.0 / μm or more or 25.0 / μm or less. It is more preferable that the number is 0 / μm or more or 23.0 / μm or less.
At this time, as a method for obtaining the average value, among the copper powder particles constituting the present copper powder, 50 or more dendritic particles may be arbitrarily measured and the average value may be obtained.
（含有塩素濃度）
　本銅粉は、銅粉中に含まれる塩素の濃度（「含有塩素濃度」とも称する）、すなわち銅粉粒子の表面ではなくて粒子内部に含まれる塩素の濃度が５ｗｔｐｐｍ～１５０ｗｔｐｐｍであるのが好ましく、中でも１０ｗｔｐｐｍ以上或いは１４０ｗｔｐｐｍ以下、その中でも２０ｗｔｐｐｍ以上或いは１３０ｗｔｐｐｍ以下、その中でも３０ｗｔｐｐｍ以上或いは１００ｗｔｐｐｍ以下、その中でも特に３０ｗｔｐｐｍ以上或いは８０ｗｔｐｐｍ以下であるのがさらに好ましい。
　本銅粉の含有塩素濃度が１５０ｗｔｐｐｍ以下であれば、接触抵抗を低く抑えることができる。なお、本銅粉の含有塩素濃度は５ｗｔｐｐｍ未満でも構わないが、５ｗｔｐｐｍ程度が含有塩素濃度の検出限界である。
　本銅粉の含有塩素濃度を５ｗｔｐｐｍ～１５０ｗｔｐｐｍとするには、塩素を添加した電解液を用いて電解を行い、電解して得られた直後の銅粉を水で洗浄するのが好ましい。 (Contained chlorine concentration)
The copper powder preferably has a concentration of chlorine contained in the copper powder (also referred to as “contained chlorine concentration”), that is, a concentration of chlorine contained in the inside of the particles rather than on the surface of the copper powder particles is 5 wtppm to 150 wtppm. Among them, 10 wtppm or more or 140 wtppm or less, more preferably 20 wtppm or more or 130 wtppm or less, more preferably 30 wtppm or more or 100 wtppm or less, and particularly preferably 30 wtppm or more or 80 wtppm or less.
If the chlorine concentration of the copper powder is 150 wtppm or less, the contact resistance can be kept low. In addition, although the content chlorine concentration of this copper powder may be less than 5 wtppm, about 5 wtppm is a detection limit of a content chlorine concentration.
In order to adjust the chlorine concentration of the copper powder to 5 wtppm to 150 wtppm, it is preferable to perform electrolysis using an electrolytic solution to which chlorine is added, and to wash the copper powder immediately after electrolysis with water.
（Ｄ５０）
　本銅粉のＤ５０、すなわちレーザー回折散乱式粒度分布測定装置によって測定される体積累積粒径Ｄ５０は、０．５μｍ～５．０μｍであるのが好ましい。本銅粉のＤ５０が０．５μｍ以上であれば、十分な導電性を確保するために必要なデンドライト状の形状を確保することが可能であり、５．０μｍ以下であれば、導電性フィルムや導電膜の厚さを十分に薄くすることができる。
　このような観点から、本銅粉のＤ５０は０．５μｍ～５．０μｍであるのが好ましく、中でも１．０μｍ以上或いは４．５μｍ以下、その中でも１．５μｍ以上或いは４．０μｍ以下、その中でも３．０μｍ以下、その中でも２．５μｍ以下であるのがさらに好ましい。
　なお、本銅粉のＤ５０を調整するには、例えばＤ５０を小さくするには、例えば電解時間を短くする、すなわち短時間のうちに電極板に析出した銅粉を掻き落とすようにするのが好ましい。但し、このような方法に限定するものではない。 (D50)
The D50 of the present copper powder, that is, the volume cumulative particle size D50 measured by a laser diffraction / scattering particle size distribution analyzer is preferably 0.5 μm to 5.0 μm. If D50 of this copper powder is 0.5 μm or more, it is possible to ensure a dendrite-like shape necessary for ensuring sufficient conductivity, and if it is 5.0 μm or less, a conductive film or The thickness of the conductive film can be sufficiently reduced.
From this point of view, the D50 of the present copper powder is preferably 0.5 μm to 5.0 μm, more preferably 1.0 μm or more and 4.5 μm or less, particularly 1.5 μm or more or 4.0 μm or less. 3.0 μm or less, more preferably 2.5 μm or less among them.
In order to adjust D50 of the present copper powder, for example, to reduce D50, for example, it is preferable to shorten the electrolysis time, that is, to scrape off the copper powder deposited on the electrode plate within a short time. . However, it is not limited to such a method.
（比表面積）
　本銅粉のＢＥＴ一点法で測定される比表面積（ＳＳＡ）は、１．２０～４．００ｍ2／ｇであるのが好ましい。１．２０ｍ2／ｇより著しく小さいと、枝が発達しておらず、特殊デンドライト状銅粉粒子が奏する効果を得られ難くなる。他方、４．００ｍ2／ｇよりも著しく大きくなると、デンドライトの枝が細くなりすぎて、ペースト加工工程で枝が折れるなどの不具合が発生して、かえって導電性を阻害する可能性がある。
　よって、本銅粉のＢＥＴ一点法で測定される比表面積は１．２０～４．００ｍ2／ｇであるのが好しく、中でも１．５０ｍ2／ｇ以上或いは３．５０ｍ2／ｇ以下、その中でも特に３．００ｍ2／ｇ以下、その中でも２．００ｍ2／ｇ以上或いは３．００ｍ2／ｇ以下であるのがさらに好ましい。 (Specific surface area)
The specific surface area (SSA) of the present copper powder measured by the BET single point method is preferably 1.20 to 4.00 m 2 / g. When it is remarkably smaller than 1.20 m 2 / g, branches are not developed, and it becomes difficult to obtain the effect exhibited by the special dendrite-like copper powder particles. On the other hand, if it is significantly larger than 4.00 m 2 / g, the dendrite branch becomes too thin, and a problem such as the branch breaking in the paste processing step may occur, and the conductivity may be hindered.
Therefore, the specific surface area as measured by single point method BET of the copper powder is 1.20 ~ 4.00m 2 / g at and even good properly, inter alia 1.50 m 2 / g or more or 3.50 m 2 / g or less, particularly 3.00 m 2 / g or less among them, still more preferably 2.00 m 2 / g or more or 3.00 m 2 / g or less among them.
（ＳＳＡ／Ｄ５０）
　本銅粉は、Ｄ５０に対する比表面積（ＳＳＡ）の比率が、０．３～２．０ｍ2／（ｇ・μｍ）であるのが好ましい。ＳＳＡ／Ｄ５０が０．３ｍ2／（ｇ・μｍ）以上であれば、分岐枝が発達しているために導電フィラー同士の接点確保が十分であり、２．０以下であれば、枝が細くなり過ぎず導電フィラーとしてロール混練やフィルタリングした際に形状が崩れてしまうこともない。
　よって、本銅粉のＳＳＡ／Ｄ５０は０．３～２．０ｍ2／（ｇ・μｍ）であるのが好しく、中でも０．４ｍ2／（ｇ・μｍ）以上或いは１．８ｍ2／（ｇ・μｍ）以下、その中でも０．５ｍ2／（ｇ・μｍ）以上或いは１．６ｍ2／（ｇ・μｍ）以下であるのがさらに好ましい。特に０．７ｍ2／（ｇ・μｍ）以上或いは１．５ｍ2／（ｇ・μｍ）以下であるのがさらに好ましい。 (SSA / D50)
The copper powder preferably has a specific surface area (SSA) ratio of D50 to 0.3 to 2.0 m 2 / (g · μm). If the SSA / D50 is 0.3 m 2 / (g · μm) or more, the branch branch is developed, so that the contact between the conductive fillers is sufficient, and if it is 2.0 or less, the branch is thin. The shape does not collapse when roll kneading or filtering as a conductive filler.
Therefore, the SSA / D50 of the present copper powder is preferably 0.3 to 2.0 m 2 / (g · μm), and above all, 0.4 m 2 / (g · μm) or more, or 1.8 m 2 / ( g · μm) or less, more preferably 0.5 m 2 / (g · μm) or more or 1.6 m 2 / (g · μm) or less. In particular, it is more preferably 0.7 m 2 / (g · μm) or more or 1.5 m 2 / (g · μm) or less.
（タップ嵩密度：ＴＤ）
　本銅粉のタップ嵩密度は、０．３～１．５ｇ／ｃｍ3であるのが好ましい。本銅粉の粒子形状がデンドライト状において、分岐枝が密に形成されているので、タップ嵩密度は比較的低く、１．５ｇ／ｃｍ3以下となる。他方、タップ嵩密度が０．５ｇ／ｃｍ3以上であれば、吸油量を少なくすることができ、ペースト作成時に高い導電性を得ることができる。
　かかる観点から、本銅粉のタップ嵩密度は０．３～１．５ｇ／ｃｍ3であるのが好ましく、中でも０．５０ｇ／ｃｍ3以上或いは１．２ｇ／ｃｍ3以下、その中でも特に０．６０ｇ／ｃｍ3以上或いは１．１０ｇ／ｃｍ3以下、その中でも特に０．７０ｇ／ｃｍ3以上或いは１．００ｇ／ｃｍ3以下であるのがさらに好ましい。 (Tap bulk density: TD)
The tap bulk density of the copper powder is preferably 0.3 to 1.5 g / cm 3 . Since the copper powder has a dendritic particle shape and branch branches are densely formed, the tap bulk density is relatively low, being 1.5 g / cm 3 or less. On the other hand, if the tap bulk density is 0.5 g / cm 3 or more, the amount of oil absorption can be reduced, and high conductivity can be obtained during paste preparation.
From this viewpoint, it is preferred tapped bulk density of the copper powder is 0.3 ~ 1.5g / cm 3, among them 0.50 g / cm 3 or more, or 1.2 g / cm 3 or less, among the 0. 60 g / cm 3 or more, or 1.10 g / cm 3 or less, and even more preferably in particular 0.70 g / cm 3 or more, or 1.00 g / cm 3 or less therein.
（吸油量）
　本銅粉の吸油量（ＪＩＳＫ５１０１）は、３０～１００ｍＬ／１００ｇであるのが好ましい。
　銅粉の吸油量（ＪＩＳＫ５１０１）が３０ｍＬ／１００ｇ以上であれば、通常の銅粉に比べて、少ない銅粉で多くの油を吸収することができると言えるから、微粒であっても少ない量の導電材で機能を発揮することができる。
　かかる観点から、本銅粉の吸油量（ＪＩＳＫ５１０１）は３０～１００ｍＬ／１００ｇであるのが好ましく、中でも４０ｍＬ／１００ｇ以上或いは９０ｍＬ／１００ｇ以下、その中でも特に５０ｍＬ／１００ｇ以上或いは８０ｍＬ／１００ｇ以下であるのがさらに好ましい。 (Oil absorption)
The oil absorption (JISK5101) of the present copper powder is preferably 30 to 100 mL / 100 g.
If the oil absorption of copper powder (JISK5101) is 30 mL / 100 g or more, it can be said that more oil can be absorbed with less copper powder than ordinary copper powder. The function can be exhibited with the conductive material.
From this point of view, the oil absorption (JISK5101) of the present copper powder is preferably 30 to 100 mL / 100 g, particularly 40 mL / 100 g or more or 90 mL / 100 g or less, and particularly 50 mL / 100 g or more or 80 mL / 100 g or less. Is more preferable.
＜本銅粉の製造方法＞
　本銅粉は、所定の電解法によって製造することができる。
　電解法としては、例えば、銅イオンを含む硫酸酸性の電解液に陽極と陰極を浸漬し、これに直流電流を流して電気分解を行い、陰極表面に粉末状に銅を析出させ、機械的又は電気的方法により掻き落として回収し、水で洗浄し、乾燥し、必要に応じて篩別工程などを経て電解銅粉を製造する方法を例示できる。
　この際、電解液に少量の塩素を添加し、所定の表面粗度を備えた電極を用いて、析出後短時間のうちに掻き落とすことが本銅粉を製造するために好ましい。 <Method for producing the present copper powder>
This copper powder can be manufactured by a predetermined electrolytic method.
As an electrolysis method, for example, an anode and a cathode are immersed in a sulfuric acid electrolytic solution containing copper ions, and a direct current is passed through the electrolyte to conduct electrolysis. A method of scraping and collecting by an electric method, washing with water, drying, and producing electrolytic copper powder through a sieving step and the like as necessary can be exemplified.
At this time, it is preferable to add a small amount of chlorine to the electrolytic solution and scrape it off within a short time after deposition using an electrode having a predetermined surface roughness in order to produce the copper powder.
　電解液の塩素濃度は３～２００ｍｇ／Ｌ、中でも５ｍｇ／Ｌ以上或いは１５０ｍｇ／Ｌ以下に調整するのが好ましい。
　電極、特に陰極には、Ｔｉ電極などを使用するのが好ましい。但し、Ｔｉに限定するものではない。
　また、電極、特に陰極の表面粗度Ｒｚは、２．０μｍ以下であるのが好ましく、中でも１．０μｍ以下であるのが特に好ましい。陰極の表面粗度Ｒｚは小さい程好ましいと考えられるが、実際には０．００１μｍ以上、経済性を特に考慮すれば０．１μｍ以上であるのが工業的には実用的であると考えられる。
　表面粗度の高い通常の銅板を使用すると、表面凹凸の凸部において集中して銅粉粒子が成長してしまうため、本銅粉を得ることが難しい。 The chlorine concentration of the electrolytic solution is preferably adjusted to 3 to 200 mg / L, more preferably 5 mg / L or more or 150 mg / L or less.
A Ti electrode or the like is preferably used for the electrode, particularly the cathode. However, it is not limited to Ti.
Further, the surface roughness Rz of the electrode, particularly the cathode, is preferably 2.0 μm or less, and particularly preferably 1.0 μm or less. It is considered that the surface roughness Rz of the cathode is preferably as small as possible. However, in practice, it is considered practical that it is 0.001 μm or more, and 0.1 μm or more in consideration of economy.
When a normal copper plate having a high surface roughness is used, the copper powder particles are concentrated on the convex portions of the surface irregularities, and thus it is difficult to obtain the present copper powder.
　また、本銅粉の製造においては、電解槽の大きさ、電極枚数、電極間距離及び電解液の循環量を調整し、電極付近の電解液の銅イオン濃度が常に高くなるように調整するのが好ましい。
　ここで、一つのモデルケースを紹介すると、電解槽の大きさが２ｍ3～１０ｍ3で、電極枚数が１０～４０枚で、電極間距離が５ｃｍ～５０ｃｍである場合に、液温を２０～６０℃好ましくは３０℃以上或いは５０℃以下とし、電流密度を１０Ａ/ｍ2～５０００Ａ/ｍ2 、好ましくは１００Ａ／ｍ２以上或いは４０００Ａ／ｍ２以下とし、銅イオン濃度を５ｇ／Ｌ～５０ｇ／Ｌ好ましくは１０ｇ／Ｌ以上或いは３０ｇ／Ｌ以下とし、硫酸濃度を５０～３００ｇ／Ｌ好ましくは１００ｇ／Ｌ以上或いは２００ｇ／Ｌ以下とし、電解液の循環量を１００～１０００Ｌ／分、好ましくは１５０Ｌ／分以上或いは５００Ｌ／分以下とするように調整するのが好ましい。 In the production of the copper powder, the size of the electrolytic cell, the number of electrodes, the distance between the electrodes, and the circulation amount of the electrolyte solution are adjusted so that the copper ion concentration in the electrolyte solution near the electrodes is always increased. Is preferred.
Here, to introduce one model case, when the electrolytic cell size is 2 m 3 to 10 m 3 , the number of electrodes is 10 to 40, and the distance between the electrodes is 5 cm to 50 cm, the liquid temperature is 20 to 60 ° C., preferably 30 ° C. or more and 50 ° C. or less, current density of 10 A / m 2 to 5000 A / m 2 , preferably 100 A / m 2 or more and 4000 A / m 2 or less, and copper ion concentration of 5 g / L to 50 g / L, preferably 10 g / L or more or 30 g / L or less, the sulfuric acid concentration is 50 to 300 g / L, preferably 100 g / L or more or 200 g / L or less, and the circulation amount of the electrolyte is 100 to 1000 L / min, preferably It is preferable to adjust so that it may be 150 L / min or more or 500 L / min or less.
　このように電解した後、電解析出した銅粉を、通常より短時間のうちに、具体的には１０秒～５分のうちに１回の頻度で、スクレーパなどで掻き落とすのが好ましい。
　そして、掻き落として回収した銅粉を、水で洗浄した後、水と混合してスラリーとするか、或いは、銅粉ケーキとした後、必要に応じて撹拌して、水などで洗浄することにより、銅粉の含有塩素濃度を低減させるのが好ましい。 After electrolysis in this manner, it is preferable to scrape off the electrolytically deposited copper powder with a scraper or the like within a shorter time than usual, specifically, once every 10 seconds to 5 minutes.
Then, after the copper powder recovered by scraping is washed with water, it is mixed with water to form a slurry, or after being made into a copper powder cake, it is stirred as necessary and washed with water or the like. Therefore, it is preferable to reduce the chlorine concentration contained in the copper powder.
　また、電解銅粉粒子の表面は、必要に応じて、有機物を用いて耐酸化処理を施し、銅粉粒子表面に有機物層を形成するようにしてもよい。必ずしも有機物層を形成する必要はないが、銅粉粒子表面の酸化による経時変化を考慮すると形成した方がより好ましい。
　この耐酸化処理に用いる有機物は、特にその種類を限定するものではなく、例えば膠、ゼラチン、有機脂肪酸、カップリング剤等を挙げることができる。
　耐酸化処理の方法、すなわち有機物層の形成方法は、乾式法でも湿式法でもよい。乾式法であれば、有機物と銅粉粒子をＶ型混合器等で混合する方法、湿式法であれば水－銅粉粒子スラリーに有機物を添加し表面に吸着させる方法等を挙げることができる。但し、これらに限ったものではない。
　例えば、電解銅粉析出後に水洗した後、銅粉ケーキ及び所望の有機物を含んだ水溶液と、有機溶媒とを混合して、銅粉表面に有機物を付着させる方法は好ましい一例である。 Moreover, the surface of the electrolytic copper powder particles may be subjected to an oxidation resistance treatment using an organic material as necessary to form an organic material layer on the surface of the copper powder particles. It is not always necessary to form the organic layer, but it is more preferable that the organic layer is formed in consideration of the change over time due to oxidation of the copper powder particle surface.
The organic substance used for this oxidation resistance treatment is not particularly limited, and examples thereof include glue, gelatin, organic fatty acid, and a coupling agent.
The oxidation-resistant treatment method, that is, the organic layer forming method may be a dry method or a wet method. In the case of a dry method, a method of mixing an organic substance and copper powder particles with a V-type mixer or the like, and in the case of a wet method, a method of adding an organic substance to a water-copper powder particle slurry and adsorbing it on the surface can be mentioned. However, it is not limited to these.
For example, a method of adhering an organic substance to the copper powder surface by mixing an aqueous solution containing a copper powder cake and a desired organic substance with an organic solvent after washing with water after electrolytic copper powder deposition is a preferred example.
＜用途＞
　本銅粉を、導電性フィルムや導電膜の導電フィラーとして用いれば、当該導電性フィルムや導電膜を十分に薄くすることができ、しかも、少ない量で導通性を確保することができる。よって、本銅粉は、導電性ペーストや導電性フィルムの導電フィラーとして特に好適である。 <Application>
If this copper powder is used as a conductive filler of a conductive film or a conductive film, the conductive film or the conductive film can be made sufficiently thin, and conductivity can be ensured in a small amount. Therefore, this copper powder is particularly suitable as a conductive filler for conductive pastes and conductive films.
　本銅粉を用いて導電性ペーストを作製する方法の一例としては、本銅粉をバインダ及び溶剤、さらに必要に応じて硬化剤やカップリング剤、腐食抑制剤などと混合して導電性ペーストを作製することができる。
　本銅粉と、他の形状又は大きさの銅粉とを混合して導電性ペーストを作製することも可能である。 As an example of a method for producing a conductive paste using the present copper powder, the present copper powder is mixed with a binder and a solvent, and further, if necessary, a curing agent, a coupling agent, a corrosion inhibitor, etc. Can be produced.
It is also possible to mix this copper powder and copper powder of another shape or size to produce a conductive paste.
　この際、バインダとしては、液状のエポキシ樹脂、フェノール樹脂、不飽和ポリエステル樹脂等を挙げることができるが、これらに限定するものではない。
　溶剤としては、テルピネオール、エチルカルビトール、カルビトールアセテート、ブチルセロソルブ等が挙げることができる。
　硬化剤としては、２－エチル－４－メチルイミダゾールなどを挙げることができる。
　腐食抑制剤としては、ベンゾチアゾール、ベンゾイミダゾール等を挙げることができる。 In this case, examples of the binder include liquid epoxy resins, phenol resins, unsaturated polyester resins, and the like, but are not limited thereto.
Examples of the solvent include terpineol, ethyl carbitol, carbitol acetate, butyl cellosolve and the like.
Examples of the curing agent include 2-ethyl-4-methylimidazole.
Examples of the corrosion inhibitor include benzothiazole and benzimidazole.
　導電性ペーストは、これを用いて基板上に回路パターンを形成して各種電気回路を形成することができる。例えば焼成済み基板或いは未焼成基板に塗布又は印刷し、加熱し、必要に応じて加圧して焼き付けることでプリント配線板や各種電子部品の電気回路や外部電極などを形成することができる。 The conductive paste can be used to form various electrical circuits by forming a circuit pattern on the substrate. For example, it is possible to form a printed wiring board, an electric circuit of various electronic components, external electrodes, and the like by applying or printing on a fired substrate or an unfired substrate, heating, pressurizing and baking as necessary.
　また、本銅粉粒子を芯材としてこれらの表面の一部又は全部を異種導電性材料、例えば金、銀、ニッケル、スズなどで被覆することができる。
　この際、本銅粉は、残留塩素を低減しているため、例えば置換法によって銅粉粒子に銀を被覆する際に、銀を均一に被覆させることができる。 Further, using the present copper powder particles as a core material, a part or all of these surfaces can be covered with a different conductive material such as gold, silver, nickel, tin and the like.
At this time, since the present copper powder reduces residual chlorine, for example, when the copper powder particles are coated with silver by a substitution method, the silver can be uniformly coated.
＜用語の説明＞
　本明細書において「Ｘ～Ｙ」（Ｘ，Ｙは任意の数字）と表現する場合、特にことわらない限り「Ｘ以上Ｙ以下」の意と共に、「好ましくはＸより大きい」或いは「好ましくＹより小さい」の意も包含する。
　また、「Ｘ以上」（Ｘは任意の数字）と表現する場合、特にことわらない限り「好ましくはＸより大きい」の意を包含し、「Ｙ以下」（Ｙは任意の数字）と表現する場合、特にことわらない限り「好ましくＹより小さい」の意を包含する。 <Explanation of terms>
In the present specification, when expressed as “X to Y” (X and Y are arbitrary numbers), unless otherwise specified, “X is greater than X” and “preferably greater than X” or “preferably greater than Y”. The meaning of “small” is also included.
In addition, when expressed as “X or more” (X is an arbitrary number), it means “preferably larger than X” unless otherwise specified, and expressed as “Y or less” (Y is an arbitrary number). In the case, unless otherwise specified, the meaning of “preferably smaller than Y” is included.
　以下、本発明の実施例について説明する。但し、本発明が以下の実施例に限定されるものではない。 Hereinafter, examples of the present invention will be described. However, the present invention is not limited to the following examples.
＜実施例１＞
　２．５ｍ×１．１ｍ×１．５ｍの大きさ（約４ｍ3）の電解槽内に、それぞれ大きさ（１．０ｍ×１．０ｍ）９枚のＴｉ製陰極板（表面粗度Ｒｚ＝０．７μｍ）と不溶性陽極板とを電極間距離５ｃｍとなるように吊設し、電解液としての硫酸銅溶液を３００Ｌ／分で循環させて、この電解液に陽極と陰極を浸漬し、これに直流電流を流して電気分解を行い、陰極表面に粉末状の銅を析出させた。
　この際、循環させる電解液の液温４０℃、Ｃｕ濃度を１５ｇ／Ｌ、硫酸（Ｈ2ＳＯ4）濃度を１５０ｇ／Ｌ、塩素濃度を５０ｍｇ／Ｌとし、且つ、電流密度を１００Ａ／ｍ２に調整して３０分間電解を実施した。 <Example 1>
In an electrolytic cell having a size of 2.5 m × 1.1 m × 1.5 m (about 4 m 3 ), 9 Ti cathode plates each having a size (1.0 m × 1.0 m) (surface roughness Rz = 0.7 μm) and an insoluble anode plate are suspended so that the distance between the electrodes is 5 cm, and a copper sulfate solution as an electrolytic solution is circulated at 300 L / min, and the anode and the cathode are immersed in the electrolytic solution. Then, direct current was passed through to conduct electrolysis, and powdered copper was deposited on the cathode surface.
At this time, the circulating electrolyte temperature is 40 ° C., the Cu concentration is 15 g / L, the sulfuric acid (H 2 SO 4 ) concentration is 150 g / L, the chlorine concentration is 50 mg / L, and the current density is 100 A / m 2. The electrolysis was carried out for 30 minutes.
　そして、陰極表面に析出した銅を、スクレーパを用いて３０秒に１回の頻度で掻き落として回収し、その後、洗浄し、銅粉１ｋｇ相当の含水銅粉ケーキを得た。このケーキを水３Ｌに分散させてスラリーとし、その後、純水で洗浄して不純物を取り除いた。
　次に、工業用ゼラチン（新田ゼラチン社製）１０ｇ／Ｌの水溶液１Ｌを加えて撹拌した後、減圧状態（１×１０-3Ｐａ）で８０℃、６時間乾燥させ、電解銅粉（サンプル）を得た。 Then, the copper deposited on the cathode surface was scraped off and collected once every 30 seconds using a scraper, and then washed to obtain a hydrous copper powder cake equivalent to 1 kg of copper powder. This cake was dispersed in 3 L of water to form a slurry, and then washed with pure water to remove impurities.
Next, 1 L of an industrial gelatin (Nitta Gelatin) 10 g / L aqueous solution was added and stirred, and then dried under reduced pressure (1 × 10 −3 Pa) at 80 ° C. for 6 hours to obtain an electrolytic copper powder (sample )
　こうして得られた電解銅粉（サンプル）を、走査型電子顕微鏡（ＳＥＭ）を用いて観察したところ、主軸の長径Ｌが０．５～５．０μｍであり、枝本数／主軸長径Ｌが３．０～２０．０本／μｍであるデンドライト状を呈する銅粉粒子（特殊デンドライト状銅粉粒子）が、全銅粉粒子のうちの８０個数％以上を占めていることを確認できた。 When the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 0.5 to 5.0 μm, and the number of branches / main shaft major axis L was 3. It was confirmed that the copper powder particles having a dendritic shape of 0 to 20.0 particles / μm (special dendritic copper powder particles) accounted for 80% by number or more of the total copper powder particles.
（実施例２）
　実施例１において、Ｃｕ濃度を１０ｇ／Ｌ、塩素濃度を１５０ｍｇ／Ｌにした以外は、実施例１と同様に電解銅粉（サンプル）を得た。
　こうして得られた電解銅粉（サンプル）を、走査型電子顕微鏡（ＳＥＭ）を用いて観察したところ、主軸の長径Ｌが０．５～５．０μｍであり、枝本数／主軸長径Ｌが３．０～２０．０本／μｍであるデンドライト状を呈する銅粉粒子（特殊デンドライト状銅粉粒子）が、全銅粉粒子のうちの８０個数％以上を占めていることを確認できた。 (Example 2)
In Example 1, an electrolytic copper powder (sample) was obtained in the same manner as in Example 1 except that the Cu concentration was 10 g / L and the chlorine concentration was 150 mg / L.
When the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 0.5 to 5.0 μm, and the number of branches / main shaft major axis L was 3. It was confirmed that the copper powder particles having a dendritic shape of 0 to 20.0 particles / μm (special dendritic copper powder particles) accounted for 80% by number or more of the total copper powder particles.
（実施例３）
　実施例１において、Ｃｕ濃度を２０ｇ／Ｌ、電流密度を２００Ａ／ｍ２にした以外は、実施例１と同様に電解銅粉（サンプル）を得た。
　こうして得られた電解銅粉（サンプル）を、走査型電子顕微鏡（ＳＥＭ）を用いて観察したところ、主軸の長径Ｌが１．０～４．５μｍであり、枝本数／主軸長径Ｌが３．０～２０．０本／μｍであるデンドライト状を呈する銅粉粒子（特殊デンドライト状銅粉粒子）が、全銅粉粒子のうちの８０個数％以上を占めていることを確認できた。 Example 3
In Example 1, an electrolytic copper powder (sample) was obtained in the same manner as in Example 1 except that the Cu concentration was 20 g / L and the current density was 200 A / m 2 .
When the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 1.0 to 4.5 μm, and the number of branches / main shaft major axis L was 3. It was confirmed that the copper powder particles having a dendritic shape of 0 to 20.0 particles / μm (special dendritic copper powder particles) accounted for 80% by number or more of the total copper powder particles.
（実施例４）
　実施例１において、塩素濃度を１５０ｍｇ／Ｌ、硫酸濃度１００ｇ／Ｌ、電流密度を２００Ａ／ｍ２にした以外は、実施例１と同様に電解銅粉（サンプル）を得た。
　こうして得られた電解銅粉（サンプル）を、走査型電子顕微鏡（ＳＥＭ）を用いて観察したところ、主軸の長径Ｌが１．５～４．０μｍであり、枝本数／主軸長径Ｌが３．５～１９．０本／μｍであるデンドライト状を呈する銅粉粒子（特殊デンドライト状銅粉粒子）が、全銅粉粒子のうちの８０個数％以上を占めていることを確認できた。 Example 4
In Example 1, an electrolytic copper powder (sample) was obtained in the same manner as in Example 1 except that the chlorine concentration was 150 mg / L, the sulfuric acid concentration was 100 g / L, and the current density was 200 A / m 2 .
When the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 1.5 to 4.0 μm, and the number of branches / main shaft major axis L was 3. It was confirmed that copper powder particles having a dendritic shape of 5 to 19.0 particles / μm (special dendritic copper powder particles) accounted for 80% by number or more of the total copper powder particles.
（実施例５）
　実施例１において、塩素濃度を２００ｍｇ／Ｌ、硫酸濃度２００ｇ／Ｌにした以外は、実施例１と同様に電解銅粉（サンプル）を得た。
　こうして得られた電解銅粉（サンプル）を、走査型電子顕微鏡（ＳＥＭ）を用いて観察したところ、主軸の長径Ｌが１．０～５．０μｍであり、枝本数／主軸長径Ｌが６．０～１８．０本／μｍであるデンドライト状を呈する銅粉粒子（特殊デンドライト状銅粉粒子）が、全銅粉粒子のうちの８０個数％以上を占めていることを確認できた。 (Example 5)
In Example 1, an electrolytic copper powder (sample) was obtained in the same manner as in Example 1 except that the chlorine concentration was 200 mg / L and the sulfuric acid concentration was 200 g / L.
When the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 1.0 to 5.0 μm, and the number of branches / main shaft major axis L was 6. It was confirmed that the copper powder particles having a dendrite shape of 0 to 18.0 particles / μm (special dendritic copper powder particles) accounted for 80% by number or more of the total copper powder particles.
（実施例６）
　実施例１において、電解液の液温３０℃、塩素濃度を２００ｍｇ／Ｌ、硫酸濃度２００ｇ／Ｌにした以外は、実施例１と同様に電解銅粉（サンプル）を得た。
　こうして得られた電解銅粉（サンプル）を、走査型電子顕微鏡（ＳＥＭ）を用いて観察したところ、主軸の長径Ｌが１．５～４．０μｍであり、枝本数／主軸長径Ｌが３．５～１９．０本／μｍであるデンドライト状を呈する銅粉粒子（特殊デンドライト状銅粉粒子）が、全銅粉粒子のうちの８０個数％以上を占めていることを確認できた。 (Example 6)
In Example 1, an electrolytic copper powder (sample) was obtained in the same manner as in Example 1 except that the electrolyte temperature was 30 ° C., the chlorine concentration was 200 mg / L, and the sulfuric acid concentration was 200 g / L.
When the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 1.5 to 4.0 μm, and the number of branches / main shaft major axis L was 3. It was confirmed that copper powder particles having a dendritic shape of 5 to 19.0 particles / μm (special dendritic copper powder particles) accounted for 80% by number or more of the total copper powder particles.
（実施例７）
　実施例１において、電解液の液温５０℃、塩素濃度を１５ｍｇ／Ｌ、Ｃｕ濃度を１０ｇ／Ｌとした以外は、実施例１と同様に電解銅粉（サンプル）を得た。
　こうして得られた電解銅粉（サンプル）を、走査型電子顕微鏡（ＳＥＭ）を用いて観察したところ、主軸の長径Ｌが０．５～５．０μｍであり、枝本数／主軸長径Ｌが３．０～２０．０本／μｍであるデンドライト状を呈する銅粉粒子（特殊デンドライト状銅粉粒子）が、全銅粉粒子のうちの８０個数％以上を占めていることを確認できた。 (Example 7)
In Example 1, an electrolytic copper powder (sample) was obtained in the same manner as in Example 1 except that the electrolyte temperature was 50 ° C., the chlorine concentration was 15 mg / L, and the Cu concentration was 10 g / L.
When the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 0.5 to 5.0 μm, and the number of branches / main shaft major axis L was 3. It was confirmed that the copper powder particles having a dendritic shape of 0 to 20.0 particles / μm (special dendritic copper powder particles) accounted for 80% by number or more of the total copper powder particles.
（実施例８）
　実施例１において、塩素濃度を１００ｍｇ／Ｌ、Ｃｕ濃度を１０ｇ／Ｌ、電流密度を２００Ａ／ｍ２、硫酸濃度２００ｇ／Ｌにした以外は、実施例１と同様に電解銅粉（サンプル）を得た。
　こうして得られた電解銅粉（サンプル）を、走査型電子顕微鏡（ＳＥＭ）を用いて観察したところ、主軸の長径Ｌが０．５～５．０μｍであり、枝本数／主軸長径Ｌが３．０～２０．０本／μｍであるデンドライト状を呈する銅粉粒子（特殊デンドライト状銅粉粒子）が、全銅粉粒子のうちの８０個数％以上を占めていることを確認できた。 (Example 8)
In Example 1, an electrolytic copper powder (sample) was prepared in the same manner as in Example 1 except that the chlorine concentration was 100 mg / L, the Cu concentration was 10 g / L, the current density was 200 A / m 2 , and the sulfuric acid concentration was 200 g / L. Obtained.
When the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 0.5 to 5.0 μm, and the number of branches / main shaft major axis L was 3. It was confirmed that the copper powder particles having a dendritic shape of 0 to 20.0 particles / μm (special dendritic copper powder particles) accounted for 80% by number or more of the total copper powder particles.
（実施例９）
　実施例１において、塩素濃度を２００ｍｇ／Ｌ、Ｃｕ濃度を３ｇ／Ｌ、硫酸濃度２００ｇ／Ｌにした以外は、実施例１と同様に電解銅粉（サンプル）を得た。
　こうして得られた電解銅粉（サンプル）を、走査型電子顕微鏡（ＳＥＭ）を用いて観察したところ、主軸の長径Ｌが０．５～５．０μｍであり、枝本数／主軸長径Ｌが３．０～２０．０本／μｍであるデンドライト状を呈する銅粉粒子（特殊デンドライト状銅粉粒子）が、全銅粉粒子のうちの８０個数％以上を占めていることを確認できた。 Example 9
In Example 1, an electrolytic copper powder (sample) was obtained in the same manner as in Example 1 except that the chlorine concentration was 200 mg / L, the Cu concentration was 3 g / L, and the sulfuric acid concentration was 200 g / L.
When the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 0.5 to 5.0 μm, and the number of branches / main shaft major axis L was 3. It was confirmed that the copper powder particles having a dendritic shape of 0 to 20.0 particles / μm (special dendritic copper powder particles) accounted for 80% by number or more of the total copper powder particles.
（実施例１０）
　実施例１において、塩素濃度を１００ｍｇ／Ｌ、Ｃｕ濃度を２ｇ／Ｌ、電流密度を２００Ａ／ｍ２にした以外は、実施例１と同様に電解銅粉（サンプル）を得た。
　こうして得られた電解銅粉（サンプル）を、走査型電子顕微鏡（ＳＥＭ）を用いて観察したところ、主軸の長径Ｌが０．５～５．０μｍであり、枝本数／主軸長径Ｌが３．０～２０．０本／μｍであるデンドライト状を呈する銅粉粒子（特殊デンドライト状銅粉粒子）が、全銅粉粒子のうちの８０個数％以上を占めていることを確認できた。 (Example 10)
In Example 1, an electrolytic copper powder (sample) was obtained in the same manner as in Example 1 except that the chlorine concentration was 100 mg / L, the Cu concentration was 2 g / L, and the current density was 200 A / m 2 .
When the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 0.5 to 5.0 μm, and the number of branches / main shaft major axis L was 3. It was confirmed that the copper powder particles having a dendritic shape of 0 to 20.0 particles / μm (special dendritic copper powder particles) accounted for 80% by number or more of the total copper powder particles.
（比較例１）
　実施例１において、塩素濃度を１０００ｍｇ／Ｌ、Ｃｕ濃度を１０ｇ／Ｌ、電流密度を５０Ａ／ｍ２、硫酸濃度１００ｇ／Ｌにした以外は実施例１と同様に製造した。陰極表面に析出した銅を、機械的に掻き落として回収し、その後、洗浄し、銅粉１ｋｇ相当の含水銅粉ケーキを得た。このケーキを純水で洗浄して不純物を取り除いた後、工業用ゼラチン（新田ゼラチン社製）１０ｇ／Ｌの水溶液１Ｌを加えて撹拌した後、減圧状態（１×１０-3Ｐａ）で８０℃、６時間乾燥させ、電解銅粉（サンプル）を得た。
　こうして得られた電解銅粉（サンプル）を、走査型電子顕微鏡（ＳＥＭ）を用いて観察したところ、ほとんどの銅粉粒子が針状又は棒状を呈していることを確認できた。 (Comparative Example 1)
In Example 1, it manufactured like Example 1 except having made chlorine concentration into 1000 mg / L, Cu density into 10 g / L, current density to 50 A / m < 2 >, and sulfuric acid concentration into 100 g / L. The copper deposited on the cathode surface was mechanically scraped and collected, and then washed to obtain a hydrous copper powder cake equivalent to 1 kg of copper powder. The cake was washed with pure water to remove impurities, 1 L of an industrial gelatin (Nitta Gelatin Co., Ltd.) 10 g / L aqueous solution was added and stirred, and then 80 80 under reduced pressure (1 × 10 −3 Pa). It was made to dry at 5 degreeC for 6 hours, and the electrolytic copper powder (sample) was obtained.
When the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), it was confirmed that most of the copper powder particles had a needle shape or a rod shape.
（比較例２）
　実施例１において、塩素濃度を５００ｍｇ／Ｌ、Ｃｕ濃度を１０ｇ／Ｌ、電流密度を２００Ａ／ｍ２、硫酸濃度１００ｇ／Ｌにした以外は、実施例１と同様に電解銅粉（サンプル）を得た。
　こうして得られた電解銅粉（サンプル）を、走査型電子顕微鏡（ＳＥＭ）を用いて観察したところ、ほとんどの銅粉粒子は針状又は棒状を呈していることを確認できた。 (Comparative Example 2)
In Example 1, an electrolytic copper powder (sample) was prepared in the same manner as in Example 1 except that the chlorine concentration was 500 mg / L, the Cu concentration was 10 g / L, the current density was 200 A / m 2 , and the sulfuric acid concentration was 100 g / L. Obtained.
When the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), it was confirmed that most of the copper powder particles had a needle shape or a rod shape.
（比較例３）
　実施例１において、塩素濃度を４００ｍｇ／Ｌ、Ｃｕ濃度を１０ｇ／Ｌ、電流密度を２００Ａ／ｍ２、硫酸濃度１００ｇ／Ｌにした以外は、実施例１と同様に電解銅粉（サンプル）を得た。
　こうして得られた電解銅粉（サンプル）を、走査型電子顕微鏡（ＳＥＭ）を用いて観察したところ、ほとんどの銅粉粒子は針状又は棒状を呈していることを確認できた。 (Comparative Example 3)
In Example 1, an electrolytic copper powder (sample) was prepared in the same manner as in Example 1 except that the chlorine concentration was 400 mg / L, the Cu concentration was 10 g / L, the current density was 200 A / m 2 , and the sulfuric acid concentration was 100 g / L. Obtained.
When the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), it was confirmed that most of the copper powder particles had a needle shape or a rod shape.
（比較例４）
　実施例１において、塩素濃度を３００ｍｇ／Ｌ、Ｃｕ濃度を５ｇ／Ｌ、電流密度を５０Ａ／ｍ２、硫酸濃度５０ｇ／Ｌにした以外は、実施例１と同様に電解銅粉（サンプル）を得た。
　こうして得られた電解銅粉（サンプル）を、走査型電子顕微鏡（ＳＥＭ）を用いて観察したところ、主軸の長径Ｌが０．５～５．０μｍであり、枝本数／主軸長径Ｌが３．０～２０．０本／μｍであるデンドライト状を呈する銅粉粒子（特殊デンドライト状銅粉粒子）が、全銅粉粒子のうちに占める割合は８０個数％未満であった。 (Comparative Example 4)
In Example 1, an electrolytic copper powder (sample) was prepared in the same manner as in Example 1 except that the chlorine concentration was 300 mg / L, the Cu concentration was 5 g / L, the current density was 50 A / m 2 , and the sulfuric acid concentration was 50 g / L. Obtained.
When the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 0.5 to 5.0 μm, and the number of branches / main shaft major axis L was 3. The proportion of 0 to 20.0 dendritic copper powder particles (special dendritic copper powder particles) in the total copper powder particles was less than 80% by number.
（比較例５）
　実施例１において、Ｔｉ製陰極板の表面粗度Ｒｚ＝３．０μｍ、塩素濃度を１５０ｍｇ／Ｌ、Ｃｕ濃度を５ｇ／Ｌにした以外は、実施例１と同様に電解銅粉（サンプル）を得た。
　こうして得られた電解銅粉（サンプル）を、走査型電子顕微鏡（ＳＥＭ）を用いて観察したところ、主軸の長径Ｌが０．５～５．０μｍであり、枝本数／主軸長径Ｌが３．０～２０．０本／μｍであるデンドライト状を呈する銅粉粒子（特殊デンドライト状銅粉粒子）が、全銅粉粒子のうちに占める割合は８０個数％未満であった。 (Comparative Example 5)
In Example 1, the electrolytic copper powder (sample) was obtained in the same manner as in Example 1 except that the surface roughness Rz of the Ti cathode plate was 3.0 μm, the chlorine concentration was 150 mg / L, and the Cu concentration was 5 g / L. Obtained.
When the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 0.5 to 5.0 μm, and the number of branches / main shaft major axis L was 3. The proportion of 0 to 20.0 dendritic copper powder particles (special dendritic copper powder particles) in the total copper powder particles was less than 80% by number.
（比較例６）
　実施例１において、Ｔｉ製陰極板の表面粗度Ｒｚ＝５．５μｍ、塩素濃度を１００ｍｇ／Ｌ、電流密度を５０Ａ／ｍ２、硫酸濃度１００ｇ／Ｌにした以外は、実施例１と同様に電解銅粉（サンプル）を得た。
　こうして得られた電解銅粉（サンプル）を、走査型電子顕微鏡（ＳＥＭ）を用いて観察したところ、主軸の長径Ｌが０．５～５．０μｍであり、枝本数／主軸長径Ｌが３．０～２０．０本／μｍであるデンドライト状を呈する銅粉粒子（特殊デンドライト状銅粉粒子）が、全銅粉粒子のうちに占める割合は８０個数％未満であった。 (Comparative Example 6)
In Example 1, except that the surface roughness Rz of the Ti cathode plate was 5.5 μm, the chlorine concentration was 100 mg / L, the current density was 50 A / m 2 , and the sulfuric acid concentration was 100 g / L, the same as in Example 1. An electrolytic copper powder (sample) was obtained.
When the electrolytic copper powder (sample) thus obtained was observed using a scanning electron microscope (SEM), the major axis L of the main shaft was 0.5 to 5.0 μm, and the number of branches / main shaft major axis L was 3. The proportion of 0 to 20.0 dendritic copper powder particles (special dendritic copper powder particles) in the total copper powder particles was less than 80% by number.
（比較例７）
　市販のアトマイズ銅粉（三井金属社製アトマイズ銅粉、非デンドライト状、Ｄ５０：３．４μｍ）を入手し、実施例１と同様に評価してその結果を表に示した。
　アトマイズ銅粉とは、電解法ではなく、アトマイズ法によって作製した銅粉の意味である。 (Comparative Example 7)
Commercially available atomized copper powder (Atomized copper powder manufactured by Mitsui Kinzoku Co., non-dendritic, D50: 3.4 μm) was obtained, evaluated in the same manner as in Example 1, and the results are shown in the table.
The atomized copper powder means a copper powder produced by an atomizing method, not an electrolytic method.
＝評価方法＝
　実施例・比較例で得られた銅粉（サンプル）を次のように評価した。 = Evaluation method =
The copper powder (sample) obtained in Examples and Comparative Examples was evaluated as follows.
＜粒子形状の観察＞
　実施例・比較例で得た銅粉（サンプル）を、走査型電子顕微鏡（２，０００倍）にて、任意の５００個の粒子の形状をそれぞれ観察し、主軸の太さａ（「主軸太さａ」）、主軸から伸びた枝の中で最も長い枝の長さｂ（「枝長ｂ」）、主軸の長径Ｌに対する分岐枝の本数（枝本数／主軸長径Ｌ）を測定し、その平均値を表１に示した。
　なお、平均値は、デンドライト状銅粉粒子と認められる粒子の平均値である。 <Observation of particle shape>
The copper powders (samples) obtained in the examples and comparative examples were observed with a scanning electron microscope (2,000 times), and the shapes of arbitrary 500 particles were respectively observed. A ”), the length b (the“ branch length b ”) of the longest branch among the branches extending from the main axis, the number of branch branches with respect to the major axis length L (the number of branches / the major axis length L), and the average The values are shown in Table 1.
The average value is an average value of particles recognized as dendritic copper powder particles.
　また、枝本数／主軸長径Ｌが３．０～２０．０本／μｍであるデンドライト状銅粉粒子（「特殊デンドライト状銅粉粒子」と称する）が、全銅粉粒子のうちに占める個数割合を「全粒子中の特殊デンドライトの個数割合」として表１に示した。
　また、枝本数／主軸長径Ｌが３．０～２０．０本／μｍである前記特殊デンドライト状銅粉粒子が、デンドライト状銅粉粒子のうちに占める個数割合を、「デンドライト中の特殊デンドライトの個数割合」として表１に示した。
　なお、粒子形状の観察の際、粒子同士が重ならないように、カーボンテープ上に少量の銅粉（サンプル）を付けて測定を行った。 Also, the number ratio of dendritic copper powder particles (referred to as “special dendritic copper powder particles”) having the number of branches / major axis major axis L of 3.0 to 20.0 / μm in the total copper powder particles Is shown in Table 1 as “number ratio of special dendrite in all particles”.
Further, the number ratio of the special dendrite-like copper powder particles having a branch number / major axis major axis L of 3.0 to 20.0 / μm in the dendrite-like copper powder particles is expressed as “the number of special dendrites in the dendrite. The number ratio is shown in Table 1.
In the observation of the particle shape, a small amount of copper powder (sample) was attached to the carbon tape so that the particles did not overlap each other.
＜粒度測定＞
　実施例・比較例で得た銅粉（サンプル）を少量ビーカーに取り、３％トリトンＸ溶液（関東化学製）を２、３滴添加し、粉末になじませてから、０．１％ＳＮディスパーサント４１溶液(サンノプコ製)５０ｍＬを添加し、その後、超音波分散器ＴＩＰφ２０（日本精機製作所製）を用いて２分間分散処理して測定用サンプルを調製した。
　この測定用サンプルを、レーザー回折散乱式粒度分布測定装置ＭＴ３３００(日機装製)を用いて、体積累積基準Ｄ５０を測定し、表１に示した。 <Particle size measurement>
Take a small amount of copper powder (sample) obtained in Examples and Comparative Examples in a small amount of beaker, add a few drops of 3% Triton X solution (manufactured by Kanto Chemical Co., Ltd.) A sample for measurement was prepared by adding 50 mL of the Sant 41 solution (San Nopco) and then dispersing for 2 minutes using an ultrasonic disperser TIPφ20 (manufactured by Nippon Seiki Seisakusho).
This sample for measurement was measured for volume accumulation standard D50 using a laser diffraction / scattering particle size distribution measuring device MT3300 (manufactured by Nikkiso), and is shown in Table 1.
＜比表面積の測定＞
　比表面積（ＳＳＡ）は、マウンテック社製モノソーブにて、ＢＥＴ一点法で測定し、ＳＳＡとして表１に示した。 <Measurement of specific surface area>
The specific surface area (SSA) was measured by a BET single-point method using a monosorb manufactured by Mountec, and shown in Table 1 as SSA.
＜含有塩素濃度の測定＞
　実施例・比較例で得た銅粉（サンプル）を硝酸で全溶解し、得られた溶液中の塩素濃度を分光光度計で測定することにより、含有塩素濃度を測定した。
　なお、上記実施例では、電析した銅粉を洗浄して銅粉粒子表面の塩素を除去しているため、実施例で得た銅粉（サンプル）で測定される含有塩素濃度は銅粉粒子内部に存在する塩素の濃度である。 <Measurement of chlorine concentration>
The copper powder (sample) obtained in Examples and Comparative Examples was completely dissolved with nitric acid, and the chlorine concentration in the obtained solution was measured with a spectrophotometer to measure the chlorine concentration.
In addition, in the said Example, since the electrodeposited copper powder is wash | cleaned and the chlorine of the copper powder particle surface is removed, the content chlorine concentration measured with the copper powder (sample) obtained in the Example is copper powder particle | grains. This is the concentration of chlorine present inside.
＜タップ嵩密度（ＴＤ）測定＞
　実施例・比較例で得た銅粉（サンプル）のタップ嵩密度（ｇ／ｃｍ3）は、試料２００ｇを用いてパウダーテスターＰＴ－Ｅ型（ホソカワミクロン製）により測定した。 <Tap bulk density (TD) measurement>
The tap bulk density (g / cm 3 ) of the copper powder (sample) obtained in Examples and Comparative Examples was measured with a powder tester PT-E type (manufactured by Hosokawa Micron) using 200 g of the sample.
＜吸油量の測定＞
　実施例・比較例で得た銅粉（サンプル）の吸油量（ｍｌ／１００ｇ）は、ＪＩＳ５１０１に準じて測定した。 <Measurement of oil absorption>
The oil absorption (ml / 100 g) of the copper powder (sample) obtained in Examples and Comparative Examples was measured according to JIS5101.
＜薄膜化評価＞
　実施例・比較例で得た銅粉（サンプル）５５ｇと、バインダとしてエポキシ樹脂（ＤＩＣ製　ＥＰＩＣＬＯＮ８５０）２０ｇと、有機溶剤としてトルエン２５ｇとを混合してペーストを作成した。
　次いで、バーコーターで幅２００ｍｍ、ギャップが１５μｍとなるように、ＰＥＴ基材の上に、前記ペーストを塗工した後、大気熱風乾燥炉にて１２０℃１０分で乾燥させ、厚さ５μｍの塗膜を得た。
　得られた塗膜を、光学顕微鏡（倍率１００倍）によって観察し、塗膜外観評価を行った。
　評価ランクとしては、塗工長１００ｍｍのエリアで塗膜カスレ不良が５箇所未満のモードを「◎（良好）」、５以上１０以下を「○（合格）」、１１以上を「×（不良）」と判定した。 <Thin film evaluation>
A paste was prepared by mixing 55 g of the copper powder (sample) obtained in Examples and Comparative Examples, 20 g of an epoxy resin (EPICLON 850 manufactured by DIC) as a binder, and 25 g of toluene as an organic solvent.
Next, the paste was applied on a PET substrate so that the width was 200 mm and the gap was 15 μm with a bar coater, and then dried in an atmospheric hot air drying oven at 120 ° C. for 10 minutes. A membrane was obtained.
The obtained coating film was observed with an optical microscope (magnification 100 times) to evaluate the appearance of the coating film.
As the evaluation rank, a mode in which the coating film failure is less than 5 in an area of a coating length of 100 mm is “「 (good) ”, 5 to 10 is“ ◯ (pass) ”, and 11 or more is“ × (defective) ”. Was determined.
＜体積抵抗率の測定＞
　圧粉抵抗測定システム（三菱化学ＰＤ－４１）と抵抗率測定器（三菱化学ＭＣＰ－Ｔ６００）を用いて圧粉抵抗値を測定した。試料５ｇをプローブシリンダへ投入し、プローブユニットをＰＤ－４１へセットした。４探針法により、油圧ジャッキによって１０ｋＮの荷重をかけたときの抵抗値を、ＭＣＰ－Ｔ６００を用いて測定した。そして、測定した抵抗値と試料厚みから、体積抵抗率を算出した。 <Measurement of volume resistivity>
The dust resistance value was measured using a dust resistance measurement system (Mitsubishi Chemical PD-41) and a resistivity meter (Mitsubishi Chemical MCP-T600). 5 g of the sample was put into the probe cylinder, and the probe unit was set on PD-41. The resistance value when a load of 10 kN was applied by a hydraulic jack was measured using the MCP-T600 by the 4-probe method. And the volume resistivity was computed from the measured resistance value and sample thickness.
＜シート抵抗粉測定時の粉充填量＞
　実施例・比較例で得た銅粉（サンプル）適量と、バインダとしてエポキシ樹脂（ＤＩＣ製　ＥＰＩＣＬＯＮ８５０）２０ｇと、有機溶剤としてトルエン２５ｇとを混合してペーストを作成した。
　次いで、バーコーターで幅２００ｍｍ、ギャップが１５μｍとなるように、ＰＥＴ基材の上に、前記ペーストを塗工した後、大気熱風乾燥炉にて１２０℃１０分で乾燥させ、厚さ５μｍの塗膜を得た。
　得られた塗膜を、抵抗率測定器（三菱化学ＭＣＰ－Ｔ６００）を用いて、４探針法によりシート抵抗値を測定した。
　この際、シート抵抗値と測定された際の銅粉（サンプル）の充填量を測定し、測定して得られた銅粉の充填量（重量）を、銅粉とエポキシ樹脂の合計重量（１００ｗｔ％）で除算し、その値を表中に「シート抵抗粉測定時の粉充填量（ｗｔ％）」として示した。
　なお、実施例１～１０で得られた銅粉に関しては、粉同士が十分に接触して抵抗値を測定することができたが、比較例１～７で得られた銅粉に関しては、抵抗値が高すぎてオーバーレンジとなり測定できなかった（表には「－」と示した）。 <Powder filling amount when measuring sheet resistance powder>
A paste was prepared by mixing an appropriate amount of the copper powder (sample) obtained in Examples and Comparative Examples, 20 g of an epoxy resin (EPICLON 850 manufactured by DIC) as a binder, and 25 g of toluene as an organic solvent.
Next, the paste was applied on a PET substrate so that the width was 200 mm and the gap was 15 μm with a bar coater, and then dried in an atmospheric hot air drying oven at 120 ° C. for 10 minutes. A membrane was obtained.
The resulting coating film was measured for sheet resistance by a four-probe method using a resistivity meter (Mitsubishi Chemical MCP-T600).
At this time, the sheet resistance value and the filling amount of the copper powder (sample) at the time of measurement were measured, and the filling amount (weight) of the copper powder obtained by the measurement was determined as the total weight of the copper powder and the epoxy resin (100 wt. %), And the value was shown in the table as “powder filling amount (wt%) when measuring sheet resistance powder”.
In addition, regarding the copper powders obtained in Examples 1 to 10, the powders were sufficiently in contact with each other to measure the resistance value. However, regarding the copper powders obtained in Comparative Examples 1 to 7, the resistance was The value was too high to be overranged and could not be measured (shown as “-” in the table).
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
（考察）
　上記実施例及びこれまで発明が行ってきた試験結果から、電解液に少量の塩素を添加し、所定の表面粗度を備えた電極を用いて電解を行い、析出後短時間のうちに掻き落として水で洗浄することにより、上記実施例のような銅粉を製造できることが分かった。 (Discussion)
From the above examples and test results that have been performed by the present invention, a small amount of chlorine is added to the electrolytic solution, electrolysis is performed using an electrode having a predetermined surface roughness, and scraped off within a short time after deposition. It was found that the copper powder as in the above examples can be produced by washing with water.
　実施例１～１０で得られた銅粉の粒子を、走査型電子顕微鏡（ＳＥＭ）を用いて観察した結果、いずれの銅粉も、主軸の長径Ｌが０．５～５．０μｍであり、枝本数／主軸長径Ｌが３．０～２０．０本／μｍ、中でも４．０本／μｍ以上或いは１９．０本／μｍ以下、その中でも５．０本／μｍ以上或いは１８．０本／μｍ以下、その中でも特に６．０本／μｍ以上或いは１８．０本／μｍ以下であるデンドライト状を呈する銅粉粒子が、全銅粉粒子のうちの８０個数％以上を占めていることを確認できた。 As a result of observing the copper powder particles obtained in Examples 1 to 10 using a scanning electron microscope (SEM), the major axis L of each of the copper powders is 0.5 to 5.0 μm. Number of branches / major axis major axis L is 3.0 to 20.0 / μm, especially 4.0 / μm or more or 19.0 / μm or less, and more preferably 5.0 / μm or more or 18.0 / Confirmed that the copper powder particles having a dendrite shape of μm or less, particularly 6.0 particles / μm or more or 18.0 particles / μm or less occupy 80% by number or more of the total copper powder particles. did it.
　上記実施例及び比較例、並びにこれまで行ってきた試験結果から、塩素の濃度が５ｗｔｐｐｍ～１５０ｗｔｐｐｍであり、Ｄ５０が０．５μｍ～５．０μｍであり、主軸の長径Ｌに対する分岐枝の本数（枝本数／主軸長径Ｌ）が３．０～２０．０本／μｍであるデンドライト状を呈する銅粉粒子（特殊デンドライト状銅粉粒子）が、全銅粉粒子のうちの８０個数％以上を占めていれば、導電性フィルムや導電膜を十分に薄くすることができ、しかも、少ない量で導電特性を得ることができるものと考えることができる。 From the above examples and comparative examples, and the results of tests conducted so far, the concentration of chlorine is 5 wtppm to 150 wtppm, D50 is 0.5 μm to 5.0 μm, and the number of branch branches with respect to the major axis L of the main shaft (branches Dendritic copper powder particles (special dendritic copper powder particles) whose number / major axis major axis L) is 3.0 to 20.0 / μm account for 80% or more of all copper powder particles. Then, it can be considered that the conductive film and the conductive film can be made sufficiently thin, and the conductive characteristics can be obtained with a small amount.

Claims (7)

  1. 　銅粉中に含まれる塩素の濃度が５ｗｔｐｐｍ～１５０ｗｔｐｐｍであり、
    　レーザー回折散乱式粒度分布測定装置によって測定される体積累積粒径Ｄ５０が０．５μｍ～５．０μｍであり、
    　走査型電子顕微鏡（ＳＥＭ）を用いて銅粉粒子を観察した際、一本の主軸を備えており、該主軸から複数の枝が斜めに分岐して、二次元的或いは三次元的に成長したデンドライト状を呈し、かつ、主軸の長径Ｌに対する分岐枝の本数（枝本数／主軸長径Ｌ）が３．０～２０．０本／μｍであるデンドライト状を呈する銅粉粒子（以下「特殊デンドライト状銅粉粒子」と称する）が、全銅粉粒子のうちの８０個数％以上を占めることを特徴とする銅粉。     The concentration of chlorine contained in the copper powder is 5 wtppm to 150 wtppm,
    The volume cumulative particle size D50 measured by a laser diffraction / scattering particle size distribution analyzer is 0.5 μm to 5.0 μm,
    When observing copper powder particles using a scanning electron microscope (SEM), it has a single main axis, and a plurality of branches branch obliquely from the main axis and grow in two or three dimensions. Copper powder particles having a dendritic shape and having a dendritic shape with the number of branch branches (the number of branches / the major axis major axis L) with respect to the major axis L being 3.0 to 20.0 / μm (hereinafter referred to as “special dendrite-like” The copper powder is characterized in that 80% by number or more of all the copper powder particles are referred to as “copper powder particles”.
  2. 　上記特殊デンドライト状銅粉粒子は、主軸の長径Ｌが０．５～５．０μｍであることを特徴とする請求項１に記載の銅粉。 2. The copper powder according to claim 1, wherein the special dendrite-like copper powder particles have a major axis L of 0.5 to 5.0 μm.
  3. 　ＢＥＴ一点法で測定される比表面積が１．２～４．０ｍ2／ｇであることを特徴とする請求項１又は２に記載の銅粉。 3. The copper powder according to claim 1, wherein the specific surface area measured by the BET single point method is 1.2 to 4.0 m 2 / g.
  4. 　上記Ｄ５０に対する比表面積（ＳＳＡ）の比率が０．３～２．０ｍ2／（ｇ・μｍ）であることを特徴とする請求項１～３の何れかに記載の銅粉。 4. The copper powder according to claim 1, wherein the ratio of the specific surface area (SSA) to D50 is 0.3 to 2.0 m 2 / (g · μm).
  5. 　タップ嵩密度が０．３～１．５ｇ／ｃｍ3であることを特徴とする請求項１～４の何れかに記載の銅粉。 The copper powder according to any one of claims 1 to 4, wherein the tap bulk density is 0.3 to 1.5 g / cm 3 .
  6. 　吸油量（ＪＩＳＫ５１０１）が３０～１００ｍＬ／１００ｇであることを特徴とする請求項１～４の何れかに記載の銅粉。 The copper powder according to any one of claims 1 to 4, wherein the oil absorption (JISK5101) is 30 to 100 mL / 100 g.
  7. 　電解によって得られる電解銅粉であることを特徴とする請求項１～６の何れかに記載の銅粉。
          7. The copper powder according to claim 1, which is an electrolytic copper powder obtained by electrolysis.
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JP2017066461A (en) * 2015-09-29 2017-04-06 住友金属鉱山株式会社 Method for producing copper powder, and method for producing conductive paste using the same
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JP5907302B1 (en) * 2015-05-15 2016-04-26 住友金属鉱山株式会社 Copper powder, copper paste using the same, conductive paint, conductive sheet, and method for producing copper powder
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