JP2010174348A - Copper powder and method for producing the same - Google Patents
Copper powder and method for producing the same Download PDFInfo
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- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 title claims abstract description 256
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 32
- 239000002245 particle Substances 0.000 claims abstract description 202
- 238000009826 distribution Methods 0.000 claims abstract description 106
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 59
- 239000007788 liquid Substances 0.000 claims abstract description 57
- 229910052802 copper Inorganic materials 0.000 claims abstract description 56
- 239000010949 copper Substances 0.000 claims abstract description 56
- 239000005749 Copper compound Substances 0.000 claims abstract description 40
- 150000001880 copper compounds Chemical class 0.000 claims abstract description 40
- JPVYNHNXODAKFH-UHFFFAOYSA-N Cu2+ Chemical compound [Cu+2] JPVYNHNXODAKFH-UHFFFAOYSA-N 0.000 claims abstract description 30
- 229910001431 copper ion Inorganic materials 0.000 claims abstract description 30
- OAKJQQAXSVQMHS-UHFFFAOYSA-N Hydrazine Chemical compound NN OAKJQQAXSVQMHS-UHFFFAOYSA-N 0.000 claims abstract description 24
- 239000007787 solid Substances 0.000 claims abstract description 18
- 239000000126 substance Substances 0.000 claims abstract description 12
- 239000005750 Copper hydroxide Substances 0.000 claims abstract description 8
- 229910001956 copper hydroxide Inorganic materials 0.000 claims abstract description 8
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 claims abstract description 7
- 239000005751 Copper oxide Substances 0.000 claims abstract description 5
- 229910000431 copper oxide Inorganic materials 0.000 claims abstract description 5
- 230000009467 reduction Effects 0.000 claims description 26
- 238000001878 scanning electron micrograph Methods 0.000 claims description 20
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 claims description 3
- 238000000034 method Methods 0.000 abstract description 39
- 239000010419 fine particle Substances 0.000 abstract description 12
- 229910052751 metal Inorganic materials 0.000 abstract description 11
- 239000002184 metal Substances 0.000 abstract description 11
- JJLJMEJHUUYSSY-UHFFFAOYSA-L Copper hydroxide Chemical compound [OH-].[OH-].[Cu+2] JJLJMEJHUUYSSY-UHFFFAOYSA-L 0.000 abstract description 6
- 238000006722 reduction reaction Methods 0.000 description 32
- 238000006243 chemical reaction Methods 0.000 description 22
- BERDEBHAJNAUOM-UHFFFAOYSA-N copper(I) oxide Inorganic materials [Cu]O[Cu] BERDEBHAJNAUOM-UHFFFAOYSA-N 0.000 description 22
- KRFJLUBVMFXRPN-UHFFFAOYSA-N cuprous oxide Chemical compound [O-2].[Cu+].[Cu+] KRFJLUBVMFXRPN-UHFFFAOYSA-N 0.000 description 22
- 229940112669 cuprous oxide Drugs 0.000 description 22
- 230000000052 comparative effect Effects 0.000 description 13
- 239000000843 powder Substances 0.000 description 12
- -1 oxoacid salts Chemical class 0.000 description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 11
- 239000000243 solution Substances 0.000 description 10
- 230000006911 nucleation Effects 0.000 description 8
- 238000010899 nucleation Methods 0.000 description 8
- 239000008139 complexing agent Substances 0.000 description 7
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- 238000003756 stirring Methods 0.000 description 7
- 239000006228 supernatant Substances 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 239000012298 atmosphere Substances 0.000 description 5
- 239000011231 conductive filler Substances 0.000 description 5
- 150000001879 copper Chemical class 0.000 description 5
- 239000011261 inert gas Substances 0.000 description 5
- 239000012299 nitrogen atmosphere Substances 0.000 description 5
- 230000003647 oxidation Effects 0.000 description 5
- 238000007254 oxidation reaction Methods 0.000 description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 4
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 4
- 229910000365 copper sulfate Inorganic materials 0.000 description 4
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000002244 precipitate Substances 0.000 description 4
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- 238000000926 separation method Methods 0.000 description 4
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 3
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 3
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 150000007942 carboxylates Chemical class 0.000 description 3
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
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- 239000002002 slurry Substances 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- KDYFGRWQOYBRFD-UHFFFAOYSA-N Succinic acid Natural products OC(=O)CCC(O)=O KDYFGRWQOYBRFD-UHFFFAOYSA-N 0.000 description 2
- 150000001298 alcohols Chemical class 0.000 description 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 238000000889 atomisation Methods 0.000 description 2
- KDYFGRWQOYBRFD-NUQCWPJISA-N butanedioic acid Chemical compound O[14C](=O)CC[14C](O)=O KDYFGRWQOYBRFD-NUQCWPJISA-N 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical compound OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- OMZSGWSJDCOLKM-UHFFFAOYSA-N copper(II) sulfide Chemical compound [S-2].[Cu+2] OMZSGWSJDCOLKM-UHFFFAOYSA-N 0.000 description 2
- 230000001186 cumulative effect Effects 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 239000000725 suspension Substances 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- FBPFZTCFMRRESA-KVTDHHQDSA-N D-Mannitol Chemical compound OC[C@@H](O)[C@@H](O)[C@H](O)[C@H](O)CO FBPFZTCFMRRESA-KVTDHHQDSA-N 0.000 description 1
- FEWJPZIEWOKRBE-JCYAYHJZSA-N Dextrotartaric acid Chemical compound OC(=O)[C@H](O)[C@@H](O)C(O)=O FEWJPZIEWOKRBE-JCYAYHJZSA-N 0.000 description 1
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 description 1
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 description 1
- WQZGKKKJIJFFOK-GASJEMHNSA-N Glucose Natural products OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-GASJEMHNSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229930195725 Mannitol Natural products 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- FEWJPZIEWOKRBE-UHFFFAOYSA-N Tartaric acid Natural products [H+].[H+].[O-]C(=O)C(O)C(O)C([O-])=O FEWJPZIEWOKRBE-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 150000001413 amino acids Chemical class 0.000 description 1
- 239000002518 antifoaming agent Substances 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- RJTANRZEWTUVMA-UHFFFAOYSA-N boron;n-methylmethanamine Chemical compound [B].CNC RJTANRZEWTUVMA-UHFFFAOYSA-N 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 150000001732 carboxylic acid derivatives Chemical class 0.000 description 1
- 150000001734 carboxylic acid salts Chemical class 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- 150000004770 chalcogenides Chemical class 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 150000004699 copper complex Chemical class 0.000 description 1
- ORTQZVOHEJQUHG-UHFFFAOYSA-L copper(II) chloride Chemical compound Cl[Cu]Cl ORTQZVOHEJQUHG-UHFFFAOYSA-L 0.000 description 1
- JZCCFEFSEZPSOG-UHFFFAOYSA-L copper(II) sulfate pentahydrate Chemical compound O.O.O.O.O.[Cu+2].[O-]S([O-])(=O)=O JZCCFEFSEZPSOG-UHFFFAOYSA-L 0.000 description 1
- ZQJIYJOLMREPMK-UHFFFAOYSA-N cyanic acid oxalonitrile Chemical compound N#CC#N.N#CO ZQJIYJOLMREPMK-UHFFFAOYSA-N 0.000 description 1
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- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
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- 239000000594 mannitol Substances 0.000 description 1
- 235000010355 mannitol Nutrition 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 235000005985 organic acids Nutrition 0.000 description 1
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Abstract
Description
本発明は、銅粉およびその製造方法に関し、特に、導電性ペーストの導電フィラーとして使用するのに適した銅粉およびその製造方法に関する。 The present invention relates to a copper powder and a method for producing the same, and more particularly to a copper powder suitable for use as a conductive filler of a conductive paste and a method for producing the same.
各種の電気電子部品の基板の表面、内部または外部に回路や電極を形成するために、多くの導電性ペーストが使用されている。このような導電性ペーストには、導電フィラー（金属粉）として銅粉や銀粉などが含まれており、平均粒径が０．１〜２０μｍの金属粉が使用されている。 Many conductive pastes are used to form circuits and electrodes on the surface, inside or outside of various electric and electronic component substrates. Such conductive paste contains copper powder, silver powder, or the like as a conductive filler (metal powder), and metal powder having an average particle size of 0.1 to 20 μm is used.
このような導電性ペーストによって電極などを形成するために、基板に塗布した導電性ペーストを焼成している。この焼成による導電性ペーストの焼結性や基板との接着強度を制御したり、それらの変動を少なくするために、粒径の揃った導電フィラー（金属粉）を使用する必要がある。また、導電性ペーストを焼成して緻密で厚い導体膜や電極を得るためには、導電性ペーストのレオロジーの調整の際に、２〜３種類の粒径の揃った金属粉を組み合わせて混合するのが有効であることが知られている。このような金属粉を組み合わせて混合するためには、異なる粒径ごとに粒径の揃った金属粉を製造する必要がある。 In order to form an electrode or the like with such a conductive paste, the conductive paste applied to the substrate is baked. In order to control the sinterability of the conductive paste by this firing and the adhesive strength with the substrate, or to reduce fluctuations thereof, it is necessary to use a conductive filler (metal powder) having a uniform particle size. In addition, in order to obtain a dense and thick conductor film or electrode by firing the conductive paste, two or three kinds of metal powders with uniform particle diameters are mixed and mixed when adjusting the rheology of the conductive paste. Is known to be effective. In order to mix and mix such metal powders, it is necessary to manufacture metal powders having a uniform particle size for each different particle size.
一般に、金属粉の製造方法として、アトマイズ法、電解法、湿式還元法などの方法が知られている。銅粉を製造する場合、アトマイズ法で得られる銅粉は、その粒度分布の幅が非常に広く、粒径の揃った粒子を得るためには、何度も分級を繰り返さなければならず、歩留まりが非常に悪くなる。また、電解法で得られる銅粉は、その粒度分布の幅が広いだけでなく、粒子の形状が樹枝状であるため、緻密で厚い導体膜や電極を形成するための導電性ペーストに使用するには適さない。これに対して、湿式還元法で得られる銅粉は、比較的粒径の揃った銅粉であり、粒子の形状が略球状であるため、導電性ペーストに使用するのに最も適している。 Generally, methods such as an atomizing method, an electrolytic method, and a wet reduction method are known as methods for producing metal powder. When producing copper powder, the copper powder obtained by the atomization method has a very wide range of particle size distribution, and in order to obtain particles having a uniform particle size, classification must be repeated many times, yield. Becomes very bad. Moreover, the copper powder obtained by the electrolytic method not only has a wide particle size distribution, but also has a dendritic shape, so it is used as a conductive paste for forming dense and thick conductor films and electrodes. Not suitable for. On the other hand, the copper powder obtained by the wet reduction method is a copper powder having a relatively uniform particle size, and the shape of the particles is substantially spherical, and thus is most suitable for use in a conductive paste.
湿式還元法によって銅粉を製造する方法としては、銅塩水溶液とアルカリ剤を反応させて水酸化銅を析出させた懸濁液に、一次還元剤を添加して亜酸化銅まで中間還元し、この亜酸化銅の懸濁液に二次還元剤を添加して金属銅まで最終還元することによって、銅粉を製造する方法が知られている（例えば、特許文献１参照）。また、銅粉と、銅化合物からなる固形成分と、液媒体とからなる混合物に、還元剤を添加して、銅化合物からなる固形成分を金属銅に還元して銅を製造する方法が知られている（例えば、特許文献２参照）。 As a method for producing copper powder by a wet reduction method, a primary reducing agent is added to a suspension obtained by reacting a copper salt aqueous solution and an alkali agent to precipitate copper hydroxide, and intermediate reduction to cuprous oxide is performed. A method of producing a copper powder by adding a secondary reducing agent to the cuprous oxide suspension and finally reducing it to metallic copper is known (for example, see Patent Document 1). Also known is a method for producing copper by adding a reducing agent to a mixture comprising a copper powder, a solid component comprising a copper compound, and a liquid medium, and reducing the solid component comprising the copper compound to metallic copper. (For example, refer to Patent Document 2).
しかし、特許文献１の方法では、比較的粒径の揃った銅粉を得ることができるが、その粒径の揃う程度は必ずしも十分ではない。また、この方法では、目標とする粒径ごとに、粒度分布の幅が狭く且つ十分に粒径の揃った銅粉を製造することができない。
However, with the method of
また、特許文献２の方法では、特許文献１の方法と比べて、目標とする粒径ごとに、粒度分布の幅が狭く且つ粒径の揃った銅粉を製造することができる。しかし、この方法では、目標とする粒径よりかなり小さい微粒子が一部に存在し、十分に粒径の揃った銅粉を製造することができない。
Moreover, in the method of Patent Document 2, copper powder having a narrow particle size distribution and uniform particle diameter can be produced for each target particle size as compared with the method of
したがって、本発明は、このような従来の問題点に鑑み、目標とする粒径ごとに、粒度分布の幅が狭く且つ微粒子数が非常に少ない銅粉を製造することができる、銅粉の製造方法を提供することを目的とする。 Therefore, in view of such conventional problems, the present invention is capable of producing copper powder having a narrow particle size distribution and a very small number of fine particles for each target particle size. It aims to provide a method.
本発明者らは、上記課題を解決するために鋭意研究した結果、体積基準の粒度分布における５０％径（Ｄ５０）が０．５μｍ以上の銅粉と還元剤を含む液に、被還元物として銅化合物および銅イオンの少なくとも一方を含む液を添加して、被還元物を金属銅に還元して銅粉を製造することにより、目標とする粒径ごとに、粒度分布の幅が狭く且つ微粒子数が非常に少ない銅粉を製造することができることを見出し、本発明を完成するに至った。 As a result of intensive studies to solve the above problems, the present inventors have found that a liquid containing a copper powder having a 50% diameter (D 50 ) in a volume-based particle size distribution of 0.5 μm or more and a reducing agent is to be reduced. And adding a liquid containing at least one of a copper compound and copper ions, and reducing the reduction target to metallic copper to produce copper powder, the width of the particle size distribution is narrow for each target particle size and The inventors have found that copper powder having a very small number of fine particles can be produced, and have completed the present invention.
すなわち、本発明による銅粉の製造方法は、体積基準の粒度分布における５０％径（Ｄ５０）が０．５μｍ以上の銅粉と還元剤を含む液に、被還元物として銅化合物および銅イオンの少なくとも一方を含む液を添加することにより、被還元物を金属銅に還元して銅粉を製造することを特徴とする。この銅粉の製造方法において、銅化合物が、固形の銅化合物であるのが好ましく、銅の酸化物または水酸化物であるのが好ましい。また、還元剤がヒドラジンまたは含水ヒドラジンであるのが好ましい。また、銅粉と還元剤を含む液と被還元物を含む液中の銅粉以外の銅の総モル数をｎ０（モル）、銅粉の体積基準の粒度分布における５０％径（Ｄ５０）をｘ０（μｍ）、銅粉の重量をｗ（ｇ）、銅の原子量をＡＷ（ｇ／モル）とすると、金属銅に還元して製造される銅粉の個数基準の粒度分布における５０％径（Ｄ５０）が、下記の数１で表されるｘ（μｍ）の±２０％以内である。
That is, the copper powder manufacturing method according to the present invention includes a copper compound and a copper ion as a reductant in a liquid containing copper powder having a 50% diameter (D 50 ) of 0.5 μm or more in a volume-based particle size distribution and a reducing agent. By adding a liquid containing at least one of the above, the material to be reduced is reduced to metallic copper to produce copper powder. In this method for producing copper powder, the copper compound is preferably a solid copper compound, and is preferably a copper oxide or hydroxide. The reducing agent is preferably hydrazine or hydrous hydrazine. Further, the total number of moles of copper other than the copper powder in the liquid containing the copper powder and the reducing agent and the liquid to be reduced is n 0 (mol), and the 50% diameter (D 50 ) in the volume-based particle size distribution of the copper powder. ) Is x 0 (μm), the weight of the copper powder is w (g), and the atomic weight of copper is AW (g / mol), 50 in the number-based particle size distribution of copper powder produced by reduction to metallic copper. The% diameter (D 50 ) is within ± 20% of x (μm) represented by the following
また、本発明による銅粉は、個数基準の粒度分布における５０％径（Ｄ５０）が０．５〜２０μｍであり、個数基準の粒度分布における１０％径（Ｄ１０）に対する９０％径（Ｄ９０）の比（Ｄ９０／Ｄ１０）が１．５以下であることを特徴とする。この銅粉において、体積基準の粒度分布における５０％径（Ｄ５０）が０．５〜２０μｍであり、体積基準の粒度分布の１０％径（Ｄ１０）に対する９０％径（Ｄ９０）の比（Ｄ９０／Ｄ１０）が１．５以下であるのが好ましい。 Further, the copper powder according to the present invention has a 50% diameter (D 50 ) in the number-based particle size distribution of 0.5 to 20 μm, and a 90% diameter (D 10 ) with respect to the 10% diameter (D 10 ) in the number-based particle size distribution. the ratio of 90) (D 90 / D 10 ) is equal to or more than 1.5. In this copper powder, the 50% diameter (D 50 ) in the volume-based particle size distribution is 0.5 to 20 μm, and the ratio of the 90% diameter (D 90 ) to the 10% diameter (D 10 ) in the volume-based particle size distribution (D 90 / D 10 ) is preferably 1.5 or less.
なお、本明細書中において、「体積基準の粒度分布」とは、湿式レーザー回折式の粒度分布測定装置による体積基準の粒度分布をいい、「体積基準の粒度分布における１０％径（Ｄ１０）、５０％径（Ｄ５０）、９０％径（Ｄ９０）」とは、湿式レーザー回折式の粒度分布測定装置により描かれる体積基準の粒度分布のグラフ、すなわち、横軸に粒径Ｄ（μｍ）、縦軸に粒径Ｄ（μｍ）以下の粒子が存在する容積Ｑ（％）をとった累積粒度曲線において、それぞれＱ％が１０％、５０％、９０％のときの粒径Ｄ（μｍ）をいう。 In the present specification, “volume-based particle size distribution” refers to a volume-based particle size distribution obtained by a wet laser diffraction type particle size distribution measuring apparatus, and “10% diameter (D 10 ) in the volume-based particle size distribution”. , 50% diameter (D 50 ), 90% diameter (D 90 ) ”is a volume-based particle size distribution graph drawn by a wet laser diffraction type particle size distribution measuring apparatus, that is, the particle diameter D (μm on the horizontal axis). ), In the cumulative particle size curve in which the vertical axis represents the volume Q (%) in which particles having a particle size D (μm) or less exist, the particle size D (μm when Q% is 10%, 50%, and 90%, respectively. ).
また、本明細書中において、「個数基準の粒度分布」とは、走査電子顕微鏡写真（ＳＥＭ画像）から求めた個数基準の粒度分布をいい、「個数基準の粒度分布における１０％径（Ｄ１０）、５０％径（Ｄ５０）、９０％径（Ｄ９０）」とは、ＳＥＭ画像に基づいて描いた個数基準の粒度分布のグラフ、すなわち、横軸に粒径Ｄ（μｍ）、縦軸に粒径Ｄ（μｍ）以下の粒子が存在する頻度Ｆ（％）をとった累積粒度曲線において、それぞれＱ％が１０％、５０％、９０％のときの粒径Ｄ（μｍ）をいう。 In the present specification, “number-based particle size distribution” refers to a number-based particle size distribution obtained from a scanning electron micrograph (SEM image), and “10% diameter (D 10 in the number-based particle size distribution)”. ), 50% diameter (D 50 ), 90% diameter (D 90 ) ”is a graph of the number-based particle size distribution drawn based on the SEM image, that is, the particle diameter D (μm) on the horizontal axis and the vertical axis In the cumulative particle size curve taking the frequency F (%) in which particles having a particle diameter D (μm) or less exist, the particle diameter D (μm) when Q% is 10%, 50%, and 90%, respectively.
本発明によれば、目標とする粒径ごとに、粒度分布の幅が狭く且つ微粒子数が非常に少ない銅粉を製造することができる。 According to the present invention, copper powder having a narrow particle size distribution and a very small number of fine particles can be produced for each target particle size.
従来の一般的な湿式還元法による銅粉の製造方法は、核発生段階と粒成長段階に分けることができる。核発生段階は、ｐＨ調整、（急冷などの）温度調整、還元剤の添加、銅イオンの添加、不純物イオンの添加、反応性ガスの導入または光照射などにより、銅粒子の核となる金属銅の超微粒子を生成させる段階である。この段階で生成する核の数は、目標とする銅粉の粒径に影響する。大きい粒径の銅粉を得る場合は、核発生数を少なくし、小さい粒径の銅粉を得る場合は、核発生数を多くすればよい。しかし、実際には、不可避的に混入する不純物の量や、製造プロセスの僅かな変動によっても、核発生数が影響を受けるので、製造される銅粉の粒径のばらつきが起こり、製造ロットごとに銅粉の粒径の変動を誘発する。次の粒成長段階は、生成した銅粒子の核を徐々に成長（銅イオンや酸化銅などを還元して銅粒子の核の表面に金属銅を析出）させることにより、目標とする粒径の銅粉に調整する段階である。この段階でも、還元力が強過ぎる場合や、生成した核の総表面積が小さい場合に、銅粒子の成長と同時に新たな核（二次核）が生成して、銅粉の粒度分布のブロード化や微粒化を引き起こしてしまう。そのため、粒径の揃った銅粉を製造ロットごとに変動なく得るためには、このような核発生段階の変動と粒成長段階の変動を抑えることが必要になる。 A conventional method for producing copper powder by a wet reduction method can be divided into a nucleation stage and a grain growth stage. The nucleation stage involves adjusting the pH, adjusting the temperature (such as quenching), adding a reducing agent, adding copper ions, adding impurity ions, introducing reactive gases, or irradiating light, and forming metallic copper as the core of the copper particles. This is the stage of generating ultrafine particles. The number of nuclei generated at this stage affects the target particle size of the copper powder. When obtaining a copper powder having a large particle size, the number of nucleation is reduced, and when obtaining a copper powder having a small particle size, the number of nucleation may be increased. However, in reality, the number of nuclei is affected by the amount of impurities that are inevitably mixed and slight fluctuations in the manufacturing process. Induces fluctuations in the particle size of copper powder. In the next grain growth stage, the nuclei of the produced copper particles are gradually grown (copper ions, copper oxides, etc. are reduced to deposit copper metal on the surface of the copper particle nuclei). This is the stage of adjusting to copper powder. Even at this stage, if the reducing power is too strong or if the total surface area of the generated nuclei is small, new nuclei (secondary nuclei) are generated simultaneously with the growth of the copper particles, and the particle size distribution of the copper powder is broadened. And cause atomization. Therefore, in order to obtain a copper powder having a uniform particle size for each production lot without fluctuation, it is necessary to suppress such fluctuations in the nucleation stage and fluctuations in the grain growth stage.
一方、本発明による銅粉の製造方法の実施の形態では、体積基準の粒度分布における５０％径（Ｄ５０）が０．５μｍ以上の（核として作用する）銅粉と還元剤を含む液に、被還元物として固形の銅化合物および銅イオンの少なくとも一方を含む液を添加することにより、被還元物を金属銅に還元して銅粉を製造する。この方法では、核として作用する銅粉を反応系に導入することによって核発生段階がなくなり、これによって核発生段階の変動をなくすことができる。また、導入する銅粉の粒径は、従来の一般的な湿式還元法による銅粉の製造方法における核発生時の微小な核より大きいので、還元によって生成する金属銅が析出する総表面積が大きくなり、粒成長が促進されて二次核の発生も抑えられることから、粒成長段階の変動を制御することができる。 On the other hand, in the embodiment of the method for producing copper powder according to the present invention, the liquid containing 50% diameter (D 50 ) in the volume-based particle size distribution (D 50 ) of 0.5 μm or more (acting as a nucleus) and a reducing agent. By adding a liquid containing at least one of a solid copper compound and copper ions as a reduction target, the reduction target is reduced to metallic copper to produce copper powder. In this method, the nucleation stage is eliminated by introducing copper powder acting as a nucleus into the reaction system, thereby eliminating the fluctuation of the nucleation stage. In addition, since the particle size of the copper powder to be introduced is larger than the fine nuclei at the time of nucleation in the conventional copper powder production method by the general wet reduction method, the total surface area on which the metal copper produced by the reduction precipitates is large. Thus, since the grain growth is promoted and the generation of secondary nuclei is suppressed, fluctuations in the grain growth stage can be controlled.
また、本発明による銅粉の製造方法の実施の形態では、銅粉と還元剤を含む液および被還元物を含む液中に存在する銅のほぼ全てを粒成長に充てることができるので、導入する銅粉以外の銅成分の量（銅粉以外の銅の総モル数）、銅粉の粒径、銅粉の添加量を調整することにより、製造される銅粉の粒径を極めて精度良く制御することができる。すなわち、銅粉と還元剤を含む液および被還元物含む液中の銅粉以外の銅の総モル数をｎ０（モル）、銅粉の体積基準の粒度分布における５０％径（Ｄ５０）をｘ０（μｍ）、銅粉の重量をｗ（ｇ）、銅の原子量をＡＷ（ｇ／モル）とすると、製造される銅粉の体積基準の粒度分布における５０％径（Ｄ５０）ｘ（μｍ）は、下記の数２で表すことができる。 Further, in the embodiment of the method for producing copper powder according to the present invention, almost all of the copper present in the liquid containing the copper powder and the reducing agent and the liquid containing the reductant can be used for grain growth. By adjusting the amount of copper components other than copper powder (total number of moles of copper other than copper powder), the particle size of copper powder, and the amount of copper powder added, the particle size of the produced copper powder can be adjusted extremely accurately. Can be controlled. That is, the total number of moles of copper other than the copper powder in the liquid containing the copper powder and the reducing agent and the liquid containing the reductant is n 0 (mol), and the 50% diameter (D 50 ) in the volume-based particle size distribution of the copper powder. X 0 (μm), the weight of the copper powder is w (g), and the atomic weight of copper is AW (g / mol), the 50% diameter (D 50 ) x in the volume-based particle size distribution of the produced copper powder (Μm) can be expressed by the following formula 2.
数２中のαは補正係数である。この式では、粒径の測定方法によって、製造される銅粉の粒径の値が若干異なったり、粒子の形状によって形状係数が変化するので、粒径の測定方法や粒子の形状に適合するように係数αによる補正を加味している。この係数αは、通常０．８〜１．２の範囲に収まる。すなわち、製造される銅粉の体積基準の粒度分布における５０％径（Ｄ５０）は、数１のｘ（μｍ）の±２０％の範囲内に収まる。
Α in Equation 2 is a correction coefficient. In this equation, the value of the particle size of the copper powder produced differs slightly depending on the particle size measurement method, or the shape factor changes depending on the particle shape, so that it matches the particle size measurement method and particle shape. Is corrected by the coefficient α. This coefficient α is usually in the range of 0.8 to 1.2. That is, the 50% diameter (D 50 ) in the volume-based particle size distribution of the produced copper powder falls within ± 20% of x (μm) in
また、本発明による銅粉の製造方法の実施の形態では、従来の一般的な湿式還元法による銅粉の製造方法によって製造された銅粉と異なり、上記の数式２において、製造される銅粉の体積基準の粒度分布における５０％径（Ｄ５０）を個数基準の粒度分布における５０％径（Ｄ５０）に置き換えることもできる。本発明による銅粉の製造方法の実施の形態により製造される銅粉の個数基準の粒度分布における５０％径（Ｄ５０）は、０．５〜２０μｍであるのが好ましく、５〜２０μｍであるのがさらに好ましく、８〜１５μｍであるのが最も好ましい。 Further, in the embodiment of the method for producing copper powder according to the present invention, unlike the copper powder produced by the conventional method for producing copper powder by the wet reduction method, It may be replaced by the 50% size of the volume-based particle size distribution of (D 50) 50% diameter of the number-based particle distribution (D 50). The 50% diameter (D 50 ) in the number-based particle size distribution of the copper powder produced by the embodiment of the method for producing copper powder according to the present invention is preferably 0.5 to 20 μm, and more preferably 5 to 20 μm. Is more preferable, and it is most preferable that it is 8-15 micrometers.
本発明による銅粉の製造方法の実施の形態では、液中に銅粉以外の銅成分（銅の酸化物や水酸化物などの銅化合物）を存在させることにより、導入する銅粉の量は、従来の湿式還元法のように金属イオンの溶解度に制限されることはない。そのため、銅の供給源となる銅原子の総量を増やすことができる。すなわち、粒成長に寄与する銅原子の数の制限がなくなるため、銅粉を所望の粒径に調整し易くなり、生産性の向上につながる。また、固形の銅化合物を使用しないで、銅イオンを含む水溶液を、銅粉と還元剤を含む液中に添加して、還元により銅粉を製造することもできる。 In embodiment of the manufacturing method of the copper powder by this invention, the quantity of the copper powder introduce | transduced by making copper components (copper compounds, such as a copper oxide and a hydroxide) other than copper powder exist in a liquid. The solubility of metal ions is not limited as in the conventional wet reduction method. Therefore, it is possible to increase the total amount of copper atoms serving as a copper supply source. That is, since there is no limit on the number of copper atoms that contribute to grain growth, it becomes easier to adjust the copper powder to a desired grain size, leading to an improvement in productivity. Moreover, without using a solid copper compound, an aqueous solution containing copper ions can be added to a solution containing copper powder and a reducing agent, and copper powder can be produced by reduction.
また、銅化合物を使用する場合に、その銅の酸化数（価数）は小さい方がよい。酸化数が大きいと、還元反応が数段階になり、複数の還元反応が同時に進行する可能性があり、二次核が発生するおそれがある。また、固形の銅化合物は、共存する銅粉の粒子の表面で還元されて粒成長に寄与する場合もあれば、反応液中に一度溶出した上で溶解析出型の反応により粒成長に寄与する場合もあると考えられる。銅化合物として、銅の硫酸、硝酸、炭酸、りん酸などのオキソ酸塩、銅のハロゲン化物などの塩類、銅の硫化物などのカルコゲナイド、銅のアミノ酸塩やカルボン酸塩などの有機酸塩類などの種々の銅化合物を使用することができるが、銅の酸化物または水酸化物を使用するのが好ましい。 Moreover, when using a copper compound, the one where the oxidation number (valence) of the copper is smaller is better. When the oxidation number is large, the reduction reaction has several stages, and a plurality of reduction reactions may proceed simultaneously, and secondary nuclei may be generated. In addition, solid copper compounds may be reduced on the surface of coexisting copper powder particles to contribute to grain growth, or may be eluted once in the reaction solution and then contribute to grain growth by dissolution precipitation type reaction. It may be possible. Copper compounds such as copper sulfate, nitric acid, carbonic acid, phosphoric acid and other oxoacid salts, copper halides and other salts, copper sulfide and other chalcogenides, copper amino acid salts and carboxylate and other organic acid salts, etc. Although various copper compounds can be used, it is preferable to use copper oxides or hydroxides.
反応に使用する液は、水または有機系の液、あるいは水と有機系の液との混合液のいずれでもよい。水を使用する場合や、還元によりガスが発生するような還元剤を使用する場合には、消泡剤や表面張力の低い有機溶媒（例えば、エタノールやイソプロピルアルコールなどのアルコール類、アセトンなどのケトン類、ヘキサンなどの炭化水素類）を共存させれば、還元によって発生する窒素などのガスによる液面上昇を抑えることができる。 The liquid used for the reaction may be water, an organic liquid, or a mixed liquid of water and an organic liquid. When using water or a reducing agent that generates gas by reduction, an antifoaming agent or an organic solvent with low surface tension (for example, alcohols such as ethanol and isopropyl alcohol, ketones such as acetone) Coexisting with hydrocarbons such as hexane), the rise in liquid level due to gas such as nitrogen generated by reduction can be suppressed.
銅粉と還元剤を含む液に被還元物として銅化合物および銅イオンの少なくとも一方を含む液を添加することにより金属銅に還元する際には、急激な反応を抑制するように、すなわち二次核の発生を抑制するように、銅粉と還元剤を含む液に被還元物を含む液を徐々に添加するのが好ましく、数時間かけて連続的に添加するのが好ましい。 When reducing to metallic copper by adding a liquid containing at least one of a copper compound and copper ions as a reductant to a liquid containing copper powder and a reducing agent, so as to suppress a rapid reaction, that is, secondary In order to suppress the generation of nuclei, it is preferable to gradually add a liquid containing a reductant to a liquid containing copper powder and a reducing agent, and it is preferable to add continuously over several hours.
銅粉と還元剤を含む液中の銅粉の粒径は、小さ過ぎると、凝集が激しくなって粒度分布の幅が広くなったり、二次核が発生する場合がある。また、粒子の成長速度は、銅粉と還元剤を含む液中の銅粉の粒径に依存せず、（反応温度、還元剤や被還元物の量などの）還元条件にもよるが、単位時間当たり数μｍと略一定に維持されるので、粒径が大き過ぎると、初期粒径に対する粒成長の比率が小さくなって生産効率が悪くなる。したがって、導入する銅粉の体積基準の粒度分布における５０％径（Ｄ５０）は、０．５〜１０μｍであるのが好ましい。 If the particle size of the copper powder in the liquid containing the copper powder and the reducing agent is too small, aggregation may become intense and the width of the particle size distribution may be widened, or secondary nuclei may be generated. In addition, the growth rate of the particles does not depend on the particle size of the copper powder in the liquid containing the copper powder and the reducing agent, and depends on the reducing conditions (such as the reaction temperature, the amount of the reducing agent and the reductant), Since the particle size is maintained at a constant value of several μm per unit time, if the particle size is too large, the ratio of the grain growth to the initial particle size becomes small, resulting in poor production efficiency. Therefore, the 50% diameter (D 50 ) in the volume-based particle size distribution of the copper powder to be introduced is preferably 0.5 to 10 μm.
還元剤としては、被還元物（固形の銅化合物および銅イオンの少なくとも一方）を金属銅まで還元可能な還元剤、例えば、ヒドラジン、含水ヒドラジン、水素化ホウ素化合物、ジメチルアミンボラン、ホルマリンなどを使用することができ、制御性、取扱い性および生産性の観点から、ヒドラジンまたは含水ヒドラジンを使用するのが好ましい。還元剤の添加量は、被還元物（固形の銅化合物および銅イオンの少なくとも一方）を金属銅まで還元できる当量以上であることが必要である。但し、この還元剤の添加量が多過ぎるとコスト的に不利になるので、被還元物（固形の銅化合物および銅イオンの少なくとも一方）に対して１〜１０当量であるのが好ましい。 As the reducing agent, a reducing agent capable of reducing the substance to be reduced (at least one of solid copper compound and copper ion) to metallic copper, such as hydrazine, hydrous hydrazine, borohydride compound, dimethylamine borane, formalin, etc. is used. From the viewpoints of controllability, handleability and productivity, it is preferable to use hydrazine or hydrous hydrazine. The addition amount of the reducing agent needs to be equal to or more than an equivalent capable of reducing the reduction target (at least one of a solid copper compound and copper ions) to metallic copper. However, since there will be a cost disadvantage if there is too much addition amount of this reducing agent, it is preferable that it is 1-10 equivalent with respect to a to-be-reduced object (at least one of a solid copper compound and a copper ion).
本発明による銅粉の製造方法の実施の形態では、体積基準の粒度分布における５０％径（Ｄ５０）が０．５μｍ以上の銅粉と還元剤を含む液に、被還元物として銅化合物および銅イオンの少なくとも一方を含む液を添加しているが、逆に添加（被還元物として銅化合物および銅イオンの少なくとも一方を含む液に銅粉を添加した後に還元剤を添加）するのは好ましくない。被還元物として銅化合物および銅イオンの少なくとも一方が多く存在している液中に還元剤を（連続式または回分式で）添加していくと、被還元物（固形の銅化合物および銅イオンの少なくとも一方）が還元されて金属銅を生成する。還元剤の添加の初期段階（還元反応の初期段階）では、還元された被還元物（銅化合物および銅イオンの少なくとも一方）が、添加した銅粉の表面に析出していく。しかし、反応の中盤から後半にかけては、添加した還元剤の量が被還元物（銅化合物および銅イオンの少なくとも一方）に対して多くなる。その結果、還元反応が促進され、添加した銅粉の表面に析出するだけでなく、新たに銅粒子が析出（二次核が発生）する。還元剤は、被還元物（銅化合物および銅イオンの少なくとも一方）の還元とともに消費されるが、その消費速度と還元速度を還元剤の添加量、添加方法および（温度、ｐＨなどの）還元条件によって制御するのは非常に難しい。その結果、新たに銅粒子が析出（二次核が発生）していく。この二次核は、反応の中盤から終盤にかけて生成するため、還元反応の初期に添加した銅粉と異なり、その成長機会が相対的に少なくなり、また、新たに発生した核であることから、添加した銅粉に対して著しく微粒のため、新たに生成した銅は微粒子になる。その結果、製造された銅粉は、微粒子を一部含んだ銅粉になる。 In the embodiment of the method for producing copper powder according to the present invention, a copper compound and a reductant are contained in a liquid containing copper powder having a 50% diameter (D 50 ) in a volume-based particle size distribution of 0.5 μm or more and a reducing agent. Although a liquid containing at least one of copper ions is added, it is preferable to add reversely (adding a reducing agent after adding copper powder to a liquid containing at least one of a copper compound and copper ions as a reduction target) Absent. When a reducing agent is added (continuously or batchwise) to a liquid in which at least one of a copper compound and copper ions is present as the reductant, the reductant (solid copper compound and copper ion) At least one) is reduced to produce metallic copper. In the initial stage of addition of the reducing agent (initial stage of the reduction reaction), the reduced product to be reduced (at least one of a copper compound and copper ions) is deposited on the surface of the added copper powder. However, from the middle to the second half of the reaction, the amount of the reducing agent added increases with respect to the substance to be reduced (at least one of the copper compound and the copper ion). As a result, the reduction reaction is promoted and not only precipitates on the surface of the added copper powder but also newly precipitates copper particles (secondary nuclei are generated). The reducing agent is consumed together with the reduction of the substance to be reduced (copper compound and / or copper ion). The consumption rate and the reduction rate are determined based on the addition amount of the reducing agent, the addition method, and the reduction conditions (temperature, pH, etc.). It is very difficult to control by. As a result, new copper particles precipitate (secondary nuclei are generated). Because this secondary nucleus is generated from the middle to the end of the reaction, unlike the copper powder added at the beginning of the reduction reaction, its growth opportunities are relatively small, and because it is a newly generated nucleus, Since the added copper powder is remarkably fine, the newly formed copper becomes fine. As a result, the produced copper powder becomes a copper powder partially containing fine particles.
一方、本発明による銅粉の製造方法の実施の形態では、銅粉と還元剤を含む液に、被還元物（銅化合物および銅イオンの少なくとも一方）を添加しているので、還元剤は、添加される被還元物に対して相対的に多くなり、その結果、導入した被還元物（銅化合物および銅イオンの少なくとも一方）は、金属銅まで素早く還元され、導入した銅粉の表面に析出していく。この状態（還元剤と被還元物の物量の関係）は、反応終了まで大きく変わらないことから、新たな二次核が発生することがなく、製造された銅粉は、微粒子を含まず、粒径が非常に揃った銅粉になる。 On the other hand, in the embodiment of the method for producing copper powder according to the present invention, since the substance to be reduced (at least one of a copper compound and copper ions) is added to the liquid containing copper powder and the reducing agent, the reducing agent is As a result, the introduced reductant (at least one of the copper compound and copper ion) is rapidly reduced to metallic copper and deposited on the surface of the introduced copper powder. I will do it. Since this state (relationship between the amount of the reducing agent and the substance to be reduced) does not change significantly until the end of the reaction, no new secondary nuclei are generated, and the produced copper powder does not contain fine particles, Copper powder with very uniform diameter.
本発明による銅粉の製造方法の実施の形態によって製造された銅粉は、湿式レーザー回折式の粒度分布測定装置による体積基準の粒度分布における１０％径（Ｄ１０）に対する９０％径（Ｄ９０）の比（Ｄ９０／Ｄ１０）が１．５以下の粒度分布が狭い銅粉である。Ｄ９０／Ｄ１０が１．５を超える銅粉では、粒径が十分に揃っていないため、異なった粒径の銅粉を組み合わせて導電性ペーストの導電フィラーとして使用する際に、目的とする粒度分布の銅粉を得るのが困難になる。 The copper powder produced by the embodiment of the method for producing copper powder according to the present invention has a 90% diameter (D 90 ) with respect to a 10% diameter (D 10 ) in a volume-based particle size distribution by a wet laser diffraction type particle size distribution measuring device. ) Ratio (D 90 / D 10 ) is a copper powder having a narrow particle size distribution of 1.5 or less. In copper powder having D 90 / D 10 exceeding 1.5, since the particle diameters are not sufficiently uniform, when copper powders having different particle diameters are combined and used as a conductive filler of a conductive paste, the purpose is It becomes difficult to obtain copper powder having a particle size distribution.
また、本発明による銅粉の製造方法の実施の形態によって製造された銅粉を走査電子顕微鏡（ＳＥＭ）によって観察すると、粒径が非常に揃った銅粉であることを確認することができる。一般に、湿式レーザー回折式の粒度分布測定装置では、粒子の体積を基準とした粒度分布であり、ある粒径の銅粉に存在する微粒子を検出し難い場合がある。例えば、最小粒径／最大粒径の比が１／１０とすると、体積比は１／１０００になってしまう。そのため、ある粒径よりも小さい粒子については、体積基準の粒度分布では微量過ぎて検出されないか、無視される場合がある。そのため、湿式レーザー回折式の粒度分布測定装置による粒度分布がシャープになる場合でも、実際には検出されていない微粒子が無数に存在する場合もある。一方、ＳＥＭによる直接的な粒子の観察や、その観察から求めた個数基準の粒度分布では、真の粒度分布を求めることができる。本発明による銅粉の製造方法の実施の形態によって製造された銅粉は、ＳＥＭによる観察でも微粒子が存在せず、粒径が非常に揃った銅粉であることを確認することができる。この銅粉は、ＳＥＭ画像による個数基準の粒度分布のグラフにおいて、１０％径（Ｄ１０）に対する９０％径（Ｄ９０）の比（Ｄ９０／Ｄ１０）が１．５以下の粒度分布が狭い銅粉である。Ｄ９０／Ｄ１０が１．５を超える銅粉では、粒径が十分に揃っていないため、異なった粒径の銅粉を組み合わせて導電性ペーストの導電フィラーとして使用する際に、目的とする粒度分布の銅粉を得るのが困難になる。 Moreover, when the copper powder manufactured by embodiment of the manufacturing method of the copper powder by this invention is observed with a scanning electron microscope (SEM), it can confirm that it is a copper powder with a very uniform particle size. In general, a wet laser diffraction type particle size distribution measuring apparatus has a particle size distribution based on the volume of particles, and it may be difficult to detect fine particles present in copper powder having a certain particle size. For example, if the ratio of the minimum particle size / maximum particle size is 1/10, the volume ratio will be 1/1000. For this reason, particles smaller than a certain particle size may not be detected or ignored in the volume-based particle size distribution because they are too small. Therefore, even when the particle size distribution by the wet laser diffraction type particle size distribution measuring device becomes sharp, there may be countless fine particles that are not actually detected. On the other hand, the true particle size distribution can be obtained by directly observing particles by SEM and the number-based particle size distribution obtained from the observation. It can be confirmed that the copper powder produced by the embodiment of the method for producing copper powder according to the present invention is a copper powder having a very uniform particle size without fine particles even by observation with an SEM. The copper powder is, in the graph of the particle size distribution of number-based by SEM image, a ratio of 90% diameter to 10% diameter (D 10) (D 90) (D 90 / D 10) is 1.5 or less of particle size distribution It is a narrow copper powder. In copper powder having D 90 / D 10 exceeding 1.5, since the particle diameters are not sufficiently uniform, when copper powders having different particle diameters are combined and used as a conductive filler of a conductive paste, the purpose is It becomes difficult to obtain copper powder having a particle size distribution.
還元反応は、雰囲気制御および温調制御が可能で攪拌機能を備えた反応槽において行うのが好ましい。反応中の雰囲気としては、空気中の酸素による酸化などの副反応の進行を抑えるために、基本的には全体を通じて不活性ガス雰囲気下で行うのが好ましい。しかし、必要に応じて、アンモニアなどの反応性ガスや酸素などを導入することによって、液性を制御したり、銅や錯化剤の酸化、還元電位の調整を行ってもよい。不活性ガスとしては、コスト面から窒素を使用するのが最適であるが、アルゴンなどの希ガスを使用してもよい。 The reduction reaction is preferably carried out in a reaction vessel that can be controlled in atmosphere and temperature and has a stirring function. As an atmosphere during the reaction, in order to suppress the progress of side reactions such as oxidation by oxygen in the air, it is basically preferable to carry out under an inert gas atmosphere throughout. However, if necessary, the liquidity may be controlled by introducing a reactive gas such as ammonia, oxygen, or the like, and oxidation or reduction potential of copper or a complexing agent may be adjusted. As an inert gas, it is optimal to use nitrogen from the viewpoint of cost, but a rare gas such as argon may be used.
被還元物として銅化合物および銅イオンの少なくとも一方を含む液は、銅の塩類、銅の水酸化物、銅の酸化物などを、純水または純水と有機溶媒の混合液に、溶解または懸濁することにより調整する。銅の塩類としては、安価な硫酸銅または塩化銅を使用するのが好ましいが、銅の硝酸、炭酸、りん酸などのオキソ酸塩類、銅のハロゲン化物塩類、硫化銅などの銅カルコゲナイド類、銅のカルボン酸塩または銅のアミノ酸塩などの有機酸塩類などを使用してもよい。また、固形の銅化合物として、銅の水酸化物および酸化物の少なくとも一方を使用する場合は、溶解した銅塩類を中和などにより析出させたものを使用してもよいし、電解法などで製造した亜酸化銅粉末を使用してもよい。なお、使用する固形の銅化合物の粒径や粒度分布の制限はない。 A liquid containing at least one of a copper compound and copper ions as a reductant is prepared by dissolving or suspending copper salts, copper hydroxide, copper oxide, etc. in pure water or a mixture of pure water and an organic solvent. Adjust by turbidity. As copper salts, it is preferable to use inexpensive copper sulfate or copper chloride, but copper oxoacid salts such as nitric acid, carbonic acid and phosphoric acid, copper halide salts, copper chalcogenides such as copper sulfide, copper, and the like. Organic acid salts such as carboxylic acid salts or copper amino acid salts may be used. Moreover, when using at least one of a copper hydroxide and an oxide as a solid copper compound, a solution obtained by precipitating a dissolved copper salt by neutralization or the like may be used. The produced cuprous oxide powder may be used. In addition, there is no restriction | limiting of the particle size and particle size distribution of the solid copper compound to be used.
このようにして、被還元物として固形の銅化合物および銅イオンの少なくとも一方を含む液を用意し、この液に対して、必要に応じて、錯化剤、ｐＨ調整剤、還元剤などを添加することによって、液性、固形成分の量、粒径、銅の酸化数などの調整を行うことができる。また、銅塩としてカルボン酸塩類を使用する場合は、その塩類に含まれるカルボン酸を錯化剤として利用することもできる。 In this way, a liquid containing at least one of a solid copper compound and copper ions is prepared as a substance to be reduced, and a complexing agent, a pH adjusting agent, a reducing agent, etc. are added to this liquid as necessary. As a result, the liquidity, the amount of solid components, the particle size, the oxidation number of copper, and the like can be adjusted. Moreover, when using carboxylate as copper salt, the carboxylic acid contained in the salt can also be utilized as a complexing agent.
なお、銅イオンと錯体を形成し得る物質（錯化剤）を添加すると、急激な反応を抑制して二次核の発生を抑えたり、イオンの溶解度を向上させたり、表面性の良い（表面が滑らかな）粒子を得ることができる。錯化剤としては、酒石酸、蓚酸、クエン酸、コハク酸、エチレンジアミン四酢酸などの有機酸や、アンモニアやエチレンジアミンなどのアミン類、グリセロールやマンニトールなどのアルコール類、アミノ酸類、シアン（青酸）またはこれらの塩を使用することができる。また、錯化剤を添加しなくても、原料となる固形の金属塩類（例えば、カルボン酸塩）や、反応中の副生成物を錯化剤として利用してもよい。 If a substance capable of forming a complex with copper ions (complexing agent) is added, the rapid reaction is suppressed to suppress the generation of secondary nuclei, the ion solubility is improved, and the surface property is good (surface (Smooth) particles can be obtained. Complexing agents include organic acids such as tartaric acid, succinic acid, citric acid, succinic acid, ethylenediaminetetraacetic acid, amines such as ammonia and ethylenediamine, alcohols such as glycerol and mannitol, amino acids, cyanogen (cyanic acid) or these The salt can be used. Further, without adding a complexing agent, solid metal salts (for example, carboxylates) as raw materials and by-products during the reaction may be used as a complexing agent.
導入する銅粉としては、ある程度粒径が揃っており、球状に近い銅粉であれば、アトマイズ法や湿式還元法などによって製造された銅粉を使用できる。なお、数２のｘを算出する式における補正係数αは、反応系および測定装置が定まると一義的に定めることができ、再現性よく、目的とする粒径を有し且つ粒径分布の幅が狭い銅粉を製造することができる。 As the copper powder to be introduced, the particle diameter is uniform to some extent, and copper powder produced by an atomizing method or a wet reduction method can be used as long as the copper powder is nearly spherical. The correction coefficient α in the equation for calculating x in Equation 2 can be uniquely determined when the reaction system and the measuring apparatus are determined, has a desired particle size, and a width of the particle size distribution with good reproducibility. Can produce a narrow copper powder.
銅粉と還元剤を含む液は、不活性ガス中において適度な時間リパルプした後、被還元物として銅化合物および銅イオンの少なくとも一方を含む液を徐々に添加して、攪拌しながら還元反応を進行させる。なお、銅粉と還元剤を含む液の溶媒となる液は、還元を著しく阻害する成分（例えば、酸化剤など）でなければよく、被還元物として銅化合物および銅イオンの少なくとも一方を含む液の溶媒となる液と同じ液でもよいが、被還元物（銅化合物および銅イオンの少なくとも一方）を含まない液であることを要する。 The liquid containing the copper powder and the reducing agent is repulped in an inert gas for an appropriate period of time, and then a liquid containing at least one of a copper compound and copper ions is gradually added as a substance to be reduced, and the reduction reaction is performed while stirring. Make it progress. In addition, the liquid used as the solvent of the liquid containing the copper powder and the reducing agent may be a component that remarkably inhibits the reduction (for example, an oxidizing agent), and contains at least one of a copper compound and copper ions as a reduction target. Although it may be the same liquid as the liquid used as the solvent, it must be a liquid that does not contain the substance to be reduced (at least one of a copper compound and copper ions).
反応の終了は、銅イオン、銅錯体または銅化合物の固形成分の存在が反応液中に検出できなくなる時点とする。反応終了後は、ろ過により固液分離し、ろ別分を純水または水溶性の有機溶媒で洗浄する。なお、ろ過の代わりに、遠心分離やスプレードライなどの他の固液分離を行ってもよい。固液分離して得られたケーキを、不活性ガスまたは還元雰囲気下において５０〜３００℃の温度で数時間〜数十時間かけて乾燥することにより、粒径の揃った銅粉を得ることができる。不活性ガスとしては、窒素または希ガスを使用することができるが、水素または一酸化炭素などの還元性ガスを混合して使用してもよい。 The reaction is terminated when the presence of a copper ion, a copper complex or a solid component of the copper compound cannot be detected in the reaction solution. After completion of the reaction, solid-liquid separation is performed by filtration, and the filtered fraction is washed with pure water or a water-soluble organic solvent. In addition, you may perform other solid-liquid separations, such as centrifugation and spray drying, instead of filtration. The cake obtained by solid-liquid separation can be dried for several hours to several tens of hours at a temperature of 50 to 300 ° C. in an inert gas or a reducing atmosphere to obtain copper powder having a uniform particle size. it can. Nitrogen or a rare gas can be used as the inert gas, but a reducing gas such as hydrogen or carbon monoxide may be mixed and used.
本発明による銅粉の製造方法の実施の形態では、銅粉の粒径を大きくしながら粒径の揃った銅粉を製造することができる。すなわち、本発明による銅粉の製造方法の実施の形態では、銅粉と還元剤を含む液中に、銅被還元物として化合物および銅イオンの少なくとも一方を含む液を添加して、被還元物を金属銅に還元することによって、粒度分布の幅が狭く、微粒子が非常に少ない銅粉を製造することができる。 In the embodiment of the method for producing copper powder according to the present invention, copper powder having a uniform particle size can be produced while increasing the particle size of the copper powder. That is, in the embodiment of the method for producing copper powder according to the present invention, a liquid containing at least one of a compound and copper ions is added as a copper reductant to a liquid containing copper powder and a reducing agent, Is reduced to metallic copper, thereby producing a copper powder with a narrow particle size distribution and very few fine particles.
以下、本発明による銅粉およびその製造方法の実施例について詳細に説明する。 Hereinafter, examples of the copper powder and the method for producing the same according to the present invention will be described in detail.
［実施例１］
まず、室温で窒素雰囲気下において純水６．１ｋｇに硫酸銅５水和物２．５ｋｇ（銅のモル数＝１０モル）を溶解して硫酸銅溶液を得た。この硫酸銅溶液を１０質量％の水酸化ナトリウム溶液９．６ｋｇに添加し、攪拌して中和し、水酸化銅を生成させた。
[Example 1]
First, 2.5 kg of copper sulfate pentahydrate (number of moles of copper = 10 mol) was dissolved in 6.1 kg of pure water at room temperature in a nitrogen atmosphere to obtain a copper sulfate solution. This copper sulfate solution was added to 9.6 kg of a 10% by mass sodium hydroxide solution and neutralized by stirring to produce copper hydroxide.
次に、生成した水酸化銅を亜酸化銅まで還元可能な還元剤として、４２質量％のブドウ糖水溶液６．５ｋｇ添加し、亜酸化銅の生成を促進させるために７０℃まで昇温させ、７０℃で３０分間反応させた。その後、液温を７０℃に保持したまま、空気を４Ｌ／分で１５０分間導入して液性を安定させた後、窒素雰囲気に戻して室温まで冷却した。なお、還元剤の添加から冷却の終了までの間、溶液を攪拌し続けた。室温まで冷却した後、攪拌を止めて、生成した亜酸化銅をデカンテーションにより沈降させた。亜酸化銅が十分に沈降したことを確認した後、上澄み液を除去して、ウェットな状態の亜酸化銅（除去しきれなかった上澄み液が残存する亜酸化銅）２．５ｋｇを得た。得られる銅の収率が１００％であるとすると、ウェットな状態の亜酸化銅中に、銅１０モルに相当する亜酸化銅（７１５ｇ）が得られることになる。 Next, 6.5 kg of a 42 mass% glucose aqueous solution is added as a reducing agent capable of reducing the produced copper hydroxide to cuprous oxide, and the temperature is raised to 70 ° C. to promote the production of cuprous oxide. The reaction was carried out at 30 ° C. for 30 minutes. Thereafter, while maintaining the liquid temperature at 70 ° C., air was introduced at 4 L / min for 150 minutes to stabilize the liquid property, and then returned to a nitrogen atmosphere and cooled to room temperature. The solution was continuously stirred from the addition of the reducing agent to the end of cooling. After cooling to room temperature, stirring was stopped and the produced cuprous oxide was allowed to settle by decantation. After confirming that the cuprous oxide had sufficiently settled, the supernatant was removed to obtain 2.5 kg of wet cuprous oxide (cuprous oxide in which the supernatant that could not be removed remained). If the yield of the obtained copper is 100%, cuprous oxide (715 g) corresponding to 10 mol of copper will be obtained in the cuprous oxide in a wet state.
次に、ウェットな状態の亜酸化銅からさらに上澄み７００ｇを取り、この上澄み液と純水２４００ｇを５Ｌビーカーに入れた。一方、上澄み液７００ｇを除去した（亜酸化銅７１５ｇを含む）ウェットな状態の亜酸化銅スラリー１８００ｇを２Ｌビーカーに移し、亜酸化銅が沈降しないように攪拌を開始した。 Next, 700 g of the supernatant was further taken from the cuprous oxide in a wet state, and this supernatant and 2400 g of pure water were placed in a 5 L beaker. Meanwhile, 1800 g of the wet cuprous oxide slurry from which 700 g of the supernatant was removed (including 715 g of cuprous oxide) was transferred to a 2 L beaker, and stirring was started so that the cuprous oxide did not settle.
次に、上澄み液７００ｇと純水２４００ｇを入れた５Ｌビーカーに、（最終目標粒径１０．０μｍの銅粉を得るために）体積基準の粒度分布における５０％径（Ｄ５０）＝５．３０μｍの（核として作用する）銅粉１１１ｇを添加した後、還元剤として８０％含水ヒドラジン３７３ｇを添加し、６３０ｒｐｍで攪拌しながら十分に分散させて、窒素雰囲気中において６０℃に昇温させた。この溶液に、２Ｌビーカーにおいて攪拌されている亜酸化銅スラリーをチューブポンプによって３６０分間で連続的に添加した。この添加の終了から６０分後、亜酸化銅が確認されなかったため、反応を終了させた。 Next, in a 5 L beaker containing 700 g of the supernatant and 2400 g of pure water, 50% diameter (D 50 ) = 5.30 μm in the volume-based particle size distribution (to obtain copper powder with a final target particle size of 10.0 μm). After adding 111 g of copper powder (acting as a nucleus), 373 g of 80% hydrous hydrazine was added as a reducing agent, sufficiently dispersed while stirring at 630 rpm, and heated to 60 ° C. in a nitrogen atmosphere. To this solution, a cuprous oxide slurry stirred in a 2 L beaker was continuously added by a tube pump in 360 minutes. After 60 minutes from the end of this addition, cuprous oxide was not confirmed, so the reaction was terminated.
反応終了後、室温まで冷却し、その後、吸引ろ過により固液分離して得られたケーキを純水８Ｌで洗浄した。洗浄後のケーキを雰囲気制御可能な乾燥機に入れ、窒素雰囲気中において１２０℃で１１時間乾燥して、目的とする銅粉を得た。 After completion of the reaction, the mixture was cooled to room temperature, and then the cake obtained by solid-liquid separation by suction filtration was washed with 8 L of pure water. The cake after washing was put into a dryer capable of controlling the atmosphere, and dried at 120 ° C. for 11 hours in a nitrogen atmosphere to obtain a target copper powder.
得られた銅粉の体積基準の粒度分布を湿式レーザー回折式の粒度分布測定装置（ベックマンコールター社製のＬＳ２３０）によって測定した。その結果、得られた銅粉の体積基準の粒度分布は、Ｄ１０＝８．６２μｍ、Ｄ２５＝９．３１μｍ、Ｄ５０＝１０．１８μｍ、Ｄ７５＝１１．０７μｍ、Ｄ９０＝１１．７６μｍ、Ｄ９０／Ｄ１０＝１．３６であり、変動係数は１１．４％であった。 The volume-based particle size distribution of the obtained copper powder was measured by a wet laser diffraction particle size distribution measuring device (LS230 manufactured by Beckman Coulter, Inc.). As a result, the volume-based particle size distribution of the obtained copper powder was D 10 = 8.62 μm, D 25 = 9.31 μm, D 50 = 10.18 μm, D 75 = 11.07 μm, D 90 = 11.76 μm. D 90 / D 10 = 1.36, and the coefficient of variation was 11.4%.
また、この銅粉の個数基準の粒度分布を電解放出型走査電子顕微鏡（ＦＥ−ＳＥＭ）（日立製作所社製のＳ−４７００）により評価した。なお、ＳＥＭによって観測した銅粉の個数基準の粒度分布は、ＳＥＭ画像中に存在する粒子５００個のＨｅｙｗｏｏｄ径から算出した。また、本実施例および後述する実施例と比較例では、１０００倍の撮影視野を用いて粒径を算出したが、５００個の粒子数が測定できない場合は、複数の１０００倍の撮影視野を用いて算出した。その結果、この銅粉の個数基準の粒度分布は、Ｄ１０＝８．５１μｍ、Ｄ２５＝８．８５μｍ、Ｄ５０＝９．４５μｍ、Ｄ７５＝１０．３７μｍ、Ｄ９０＝１１．２８μｍ、Ｄ９０／Ｄ１０＝１．３３であった。なお、得られた銅粉の個数基準の粒度分布における５０％径（Ｄ５０）の最終目標粒径からのずれを、（個数基準の粒度分布における５０％径（Ｄ５０）−最終目標粒径）×１００／最終目標粒径から算出すると、−５．５％であった。 The number-based particle size distribution of the copper powder was evaluated by a field emission scanning electron microscope (FE-SEM) (S-4700 manufactured by Hitachi, Ltd.). The number-based particle size distribution of the copper powder observed by SEM was calculated from the Heywood diameter of 500 particles present in the SEM image. Further, in this example and the examples and comparative examples described later, the particle size was calculated using a 1000 × field of view, but when the number of 500 particles could not be measured, a plurality of 1000 × field of view was used. Calculated. As a result, the number-based particle size distribution of the copper powder is as follows: D 10 = 8.51 μm, D 25 = 8.85 μm, D 50 = 9.45 μm, D 75 = 10.37 μm, D 90 = 11.28 μm, D It was 90 / D 10 = 1.33. Incidentally, the deviation from the final target particle size of 50% diameter of the number-based particle distribution of the resulting copper powder (D 50), (50% diameter of the number-based particle distribution (D 50) - final target particle size ) × 100 / calculated from the final target particle size, it was −5.5%.
［実施例２］
Ｄ５０＝５．３０μｍの銅粉１１１ｇの代わりにＤ５０＝０．５２μｍの銅粉０．０９ｇを使用し、２Ｌビーカーにおいて攪拌されている亜酸化銅スラリーの添加時間を４８０分間にした以外は、実施例１と同様の方法により、銅粉を得た。この銅粉の体積基準の粒度分布を実施例１と同様の方法によって測定したところ、Ｄ１０＝８．０８μｍ、Ｄ２５＝８．９６μｍ、Ｄ５０＝１０．１２μｍ、Ｄ７５＝１１．４４μｍ、Ｄ９０＝１２．０６μｍ、Ｄ９０／Ｄ１０＝１．４９であり、変動係数は１９．４％であった。また、この銅粉の個数基準の粒度分布を実施例１と同様の方法によって測定したところ、Ｄ１０＝８．７６μｍ、Ｄ２５＝９．４３μｍ、Ｄ５０＝１０．６１μｍ、Ｄ７５＝１１．８８μｍ、Ｄ９０＝１３．１６μｍ、Ｄ９０／Ｄ１０＝１．５０であった。なお、得られた銅粉の個数基準の粒度分布における５０％径（Ｄ５０）の最終目標粒径からのずれは、６．１％であった。
[Example 2]
D 50 = using copper powder 0.09g of D 50 = 0.52 .mu.m in place of copper powder 111g of 5.30Myuemu, except that the addition time of the cuprous oxide slurry is stirred at 2L beaker 480 minutes By the same method as Example 1, copper powder was obtained. When the volume-based particle size distribution of the copper powder was measured by the same method as in Example 1, D 10 = 8.08 μm, D 25 = 8.96 μm, D 50 = 10.12 μm, D 75 = 11.44 μm, D 90 = 12.06μm, a D 90 /
［実施例３］
Ｄ５０＝５．３０μｍの銅粉１１１ｇの代わりに（最終目標粒径５．８μｍの銅粉を得るために）Ｄ５０＝２．８２μｍの銅粉８２．５ｇを使用した以外は、実施例１と同様の方法により、銅粉を得た。この銅粉の体積基準の粒度分布を実施例１と同様の方法によって測定したところ、Ｄ１０＝４．６０μｍ、Ｄ２５＝４．９９μｍ、Ｄ５０＝５．５０μｍ、Ｄ７５＝６．０５μｍ、Ｄ９０＝６．５６μｍ、Ｄ９０／Ｄ１０＝１．４３であり、変動係数は１３．０％であった。また、この銅粉の個数基準の粒度分布を実施例１と同様の方法によって測定したところ、Ｄ１０＝４．２０μｍ、Ｄ２５＝４．５３μｍ、Ｄ５０＝５．０７μｍ、Ｄ７５＝５．５５μｍ、Ｄ９０＝５．８６μｍ、Ｄ９０／Ｄ１０＝１．３９であった。なお、得られた銅粉の個数基準の粒度分布における５０％径（Ｄ５０）の最終目標粒径からのずれは、−１２．６％であった。
[Example 3]
Except for using D 50 = 5.30μm instead of copper powder 111g of (in order to obtain a copper powder final target particle size 5.8 [mu] m) copper powder 82.5g of
［実施例４］
Ｄ５０＝５．３０μｍの銅粉１１１ｇの代わりに（最終目標粒径１５．０μｍの銅粉を得るために）Ｄ５０＝５．３０μｍの銅粉２９．３３ｇを使用した以外は、実施例１と同様の方法により、銅粉を得た。この銅粉の体積基準の粒度分布を実施例１と同様の方法によって測定したところ、Ｄ１０＝１２．８７μｍ、Ｄ２５＝１３．７５μｍ、Ｄ５０＝１５．５５μｍ、Ｄ７５＝１７．４５μｍ、Ｄ９０＝１９．０４μｍ、Ｄ９０／Ｄ１０＝１．４８であり、変動係数は１８．５％であった。また、この銅粉の個数基準の粒度分布を実施例１と同様の方法によって測定したところ、Ｄ１０＝１１．６３μｍ、Ｄ２５＝１３．２１μｍ、Ｄ５０＝１４．９９μｍ、Ｄ７５＝１６．４２μｍ、Ｄ９０＝１７．３６μｍ、Ｄ９０／Ｄ１０＝１．４９であった。なお、得られた銅粉の個数基準の粒度分布における５０％径（Ｄ５０）の最終目標粒径からのずれは、−０．１％であった。
[Example 4]
Example 1 with the exception of using 29.33 g of D 50 = 5.30 μm copper powder (in order to obtain copper powder with a final target particle size of 15.0 μm) instead of 111 g of D 50 = 5.30 μm copper powder. By the same method, copper powder was obtained. When the volume-based particle size distribution of the copper powder was measured by the same method as in Example 1, D 10 = 12.87 μm, D 25 = 13.75 μm, D 50 = 15.55 μm, D 75 = 17.45 μm, D 90 = 19.04 μm, D 90 / D 10 = 1.48, and the coefficient of variation was 18.5%. Further, the number-based particle size distribution of the copper powder was measured by the same method as in Example 1. As a result, D 10 = 11.63 μm, D 25 = 13.21 μm, D 50 = 14.99 μm, D 75 = 16. They were 42 μm, D 90 = 17.36 μm, and D 90 / D 10 = 1.49. The deviation of the 50% diameter (D 50 ) from the final target particle diameter in the number-based particle size distribution of the obtained copper powder was −0.1%.
［比較例１］
まず、実施例１と同様の方法によってウェットな状態の亜酸化銅（除去しきれなかった上澄み液が残存する亜酸化銅）２．５ｋｇを得た。次に、ウェットな状態の亜酸化銅２．５ｋｇを５Ｌビーカーに移した後、純水２４００ｇを添加とともに、（最終目標粒径１０．０μｍの銅粉を得るために）Ｄ５０＝５．３０μｍの銅粉１１１ｇを添加し、６３０ｒｐｍで攪拌しながら十分に分散させて、窒素雰囲気中において６０℃に昇温させた。この溶液に、還元剤として８０％含水ヒドラジン３７３ｇをチューブポンプによって３６０分間で連続的に添加した。この添加の終了から６０分後、亜酸化銅が確認されなかったため、反応を終了させた。反応終了後、実施例１と同様の方法により、目的とする銅粉を得た。
[Comparative Example 1]
First, 2.5 kg of wet cuprous oxide (cuprous oxide in which the supernatant liquid that could not be completely removed) was obtained in the same manner as in Example 1. Next, after 2.5 kg of wet cuprous oxide was transferred to a 5 L beaker, 2400 g of pure water was added and D 50 = 5.30 μm (to obtain copper powder with a final target particle size of 10.0 μm). Of copper powder was added and sufficiently dispersed while stirring at 630 rpm, and the temperature was raised to 60 ° C. in a nitrogen atmosphere. To this solution, 373 g of 80% hydrous hydrazine as a reducing agent was continuously added by a tube pump for 360 minutes. After 60 minutes from the end of this addition, cuprous oxide was not confirmed, so the reaction was terminated. After completion of the reaction, the intended copper powder was obtained by the same method as in Example 1.
得られた銅粉の体積基準の粒度分布を実施例１と同様の方法によって測定したところ、Ｄ１０＝５．５５μｍ、Ｄ２５＝７．６２μｍ、Ｄ５０＝８．６６μｍ、Ｄ７５＝９．６３μｍ、Ｄ９０＝１０．４６μｍ、Ｄ９０／Ｄ１０＝１．８９であり、変動係数は２１．１％であった。また、この銅粉の個数基準の粒度分布を実施例１と同様の方法によって測定したところ、Ｄ１０＝１．３６μｍ、Ｄ２５＝１．９２μｍ、Ｄ５０＝４．０１μｍ、Ｄ７５＝７．７２μｍ、Ｄ９０＝９．１４μｍ、Ｄ９０／Ｄ１０＝６．７０であった。なお、得られた銅粉の個数基準の粒度分布における５０％径（Ｄ５０）の最終目標粒径からのずれは、−５９．９％であった。
When the volume-based particle size distribution of the obtained copper powder was measured by the same method as in Example 1, D 10 = 5.55 μm, D 25 = 7.62 μm, D 50 = 8.66 μm, D 75 = 9. 63μm, D 90 = 10.46μm, a D 90 /
［比較例２］
Ｄ５０＝５．３０μｍの銅粉１１１ｇの代わりに（最終目標粒径８．０μｍの銅粉を得るために）Ｄ５０＝５．３０μｍの銅粉２６０．５ｇを使用した以外は、比較例１と同様の方法により、銅粉を得た。この銅粉の体積基準の粒度分布を実施例１と同様の方法によって測定したところ、Ｄ１０＝５．５７μｍ、Ｄ２５＝６．４３μｍ、Ｄ５０＝７．２９μｍ、Ｄ７５＝８．１２μｍ、Ｄ９０＝８．８５μｍ、Ｄ９０／Ｄ１０＝１．５９であり、変動係数は２１．１％であった。また、この銅粉の個数基準の粒度分布を実施例１と同様の方法によって測定したところ、Ｄ１０＝２．１３μｍ、Ｄ２５＝２．５９μｍ、Ｄ５０＝３．４４μｍ、Ｄ７５＝６．６１μｍ、Ｄ９０＝７．６９μｍ、Ｄ９０／Ｄ１０＝３．６１であった。なお、得られた銅粉の個数基準の粒度分布における５０％径（Ｄ５０）の最終目標粒径からのずれは、−５７％であった。
[Comparative Example 2]
Comparative Example 1 except that D 50 = 5.30 μm copper powder 111 g (in order to obtain a final target particle size of 8.0 μm copper powder) D 50 = 5.30 μm copper powder 260.5 g was used instead of D 50 = 5.30 μm copper powder 111 g By the same method, copper powder was obtained. When the volume-based particle size distribution of the copper powder was measured by the same method as in Example 1, D 10 = 5.57 μm, D 25 = 6.43 μm, D 50 = 7.29 μm, D 75 = 8.12 μm, D 90 = 8.85 μm, D 90 / D 10 = 1.59, and the coefficient of variation was 21.1%. Moreover, as measured by the same method the particle size distribution of number-based copper powder as in Example 1, D 10 = 2.13μm, D 25 = 2.59μm,
実施例１〜４および比較例１〜２で得られた銅粉の体積基準の粒度分布を表１に示し、個数基準の粒度分布を表２に示す。また、実施例１〜４および比較例１〜２で得られた銅粉の体積基準の粒度分布をそれぞれ図１Ａ〜図１Ｆに示し、個数基準の粒度分布をそれぞれ図２Ａ〜図２Ｆに示す。さらに、実施例１〜４および比較例１〜２で得られた銅粉のＳＥＭ画像をそれぞれ図３Ａ〜図３Ｆに示す。 Table 1 shows the volume-based particle size distribution of the copper powders obtained in Examples 1 to 4 and Comparative Examples 1 and 2, and Table 2 shows the number-based particle size distribution. Further, the volume-based particle size distributions of the copper powders obtained in Examples 1 to 4 and Comparative Examples 1 and 2 are shown in FIGS. 1A to 1F, respectively, and the number-based particle size distributions are shown in FIGS. 2A to 2F, respectively. Furthermore, the SEM image of the copper powder obtained in Examples 1-4 and Comparative Examples 1-2 is shown to FIG. 3A-FIG. 3F, respectively.
表１、表２、図１Ａ〜図１Ｆ、図２Ａ〜図２Ｆおよび図３Ａ〜図３Ｆの結果から、実施例１〜４にように、体積基準の粒度分布における５０％径（Ｄ５０）が０．５μｍ以上の銅粉と還元剤を含む液に、被還元物として銅化合物および銅イオンの少なくとも一方を含む液を添加して、被還元物を金属銅に還元して銅粉を製造することにより、目標とする粒径ごとに、粒度分布の幅が狭く且つ微粒子数が非常に少ない銅粉を製造することができることがわかる。 From the results of Table 1, Table 2, FIGS. 1A to 1F, FIGS. 2A to 2F, and FIGS. 3A to 3F, as in Examples 1 to 4, the 50% diameter (D 50 ) in the volume-based particle size distribution is A liquid containing at least one of a copper compound and a copper ion as a reductant is added to a liquid containing copper powder of 0.5 μm or more and a reducing agent, and the reductant is reduced to metallic copper to produce copper powder. Thus, it can be seen that copper powder having a narrow particle size distribution and a very small number of fine particles can be produced for each target particle size.
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| JP2009019607A Active JP5416979B2 (en) | 2009-01-30 | 2009-01-30 | Copper powder and method for producing the same |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020105497A1 (en) * | 2018-11-20 | 2020-05-28 | 京セラ株式会社 | Production method for copper particles used in bonding , paste used in bonding, and semiconductor device and electric and electronic component |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0920903A (en) * | 1995-06-30 | 1997-01-21 | Tanaka Kikinzoku Internatl Kk | Production of monodisperse gold grain powder |
| JPH10317022A (en) * | 1997-05-22 | 1998-12-02 | Daiken Kagaku Kogyo Kk | Production of metallic particulate powder |
| JPH10330811A (en) * | 1997-06-05 | 1998-12-15 | Tanaka Kikinzoku Kogyo Kk | Production of highly crystalline palladium powder |
| JP2004307881A (en) * | 2003-04-02 | 2004-11-04 | Dowa Mining Co Ltd | Copper powder and manufacturing method therefor |
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2009
- 2009-01-30 JP JP2009019607A patent/JP5416979B2/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0920903A (en) * | 1995-06-30 | 1997-01-21 | Tanaka Kikinzoku Internatl Kk | Production of monodisperse gold grain powder |
| JPH10317022A (en) * | 1997-05-22 | 1998-12-02 | Daiken Kagaku Kogyo Kk | Production of metallic particulate powder |
| JPH10330811A (en) * | 1997-06-05 | 1998-12-15 | Tanaka Kikinzoku Kogyo Kk | Production of highly crystalline palladium powder |
| JP2004307881A (en) * | 2003-04-02 | 2004-11-04 | Dowa Mining Co Ltd | Copper powder and manufacturing method therefor |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020105497A1 (en) * | 2018-11-20 | 2020-05-28 | 京セラ株式会社 | Production method for copper particles used in bonding , paste used in bonding, and semiconductor device and electric and electronic component |
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