JP2003257245A - Foil piece shape copper powder and conductive paste using the same - Google Patents
Foil piece shape copper powder and conductive paste using the sameInfo
- Publication number
- JP2003257245A JP2003257245A JP2002060729A JP2002060729A JP2003257245A JP 2003257245 A JP2003257245 A JP 2003257245A JP 2002060729 A JP2002060729 A JP 2002060729A JP 2002060729 A JP2002060729 A JP 2002060729A JP 2003257245 A JP2003257245 A JP 2003257245A
- Authority
- JP
- Japan
- Prior art keywords
- copper powder
- particle size
- foil
- conductive paste
- less
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 title claims abstract description 67
- 239000011888 foil Substances 0.000 title abstract description 9
- 239000002245 particle Substances 0.000 claims abstract description 61
- 229910052802 copper Inorganic materials 0.000 claims abstract description 13
- 239000010949 copper Substances 0.000 claims abstract description 13
- 238000009826 distribution Methods 0.000 claims abstract description 8
- 230000001186 cumulative effect Effects 0.000 claims abstract description 3
- 239000011347 resin Substances 0.000 claims description 7
- 229920005989 resin Polymers 0.000 claims description 7
- 238000004438 BET method Methods 0.000 claims description 3
- 239000000843 powder Substances 0.000 abstract description 5
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 8
- 238000000034 method Methods 0.000 description 7
- 239000000919 ceramic Substances 0.000 description 6
- 239000002270 dispersing agent Substances 0.000 description 6
- 239000007788 liquid Substances 0.000 description 6
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 5
- 235000021355 Stearic acid Nutrition 0.000 description 4
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 239000011521 glass Substances 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical compound CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 description 4
- OQCDKBAXFALNLD-UHFFFAOYSA-N octadecanoic acid Natural products CCCCCCCC(C)CCCCCCCCC(O)=O OQCDKBAXFALNLD-UHFFFAOYSA-N 0.000 description 4
- 239000008117 stearic acid Substances 0.000 description 4
- 230000003746 surface roughness Effects 0.000 description 4
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 238000000635 electron micrograph Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 239000004576 sand Substances 0.000 description 3
- JJLJMEJHUUYSSY-UHFFFAOYSA-L Copper hydroxide Chemical compound [OH-].[OH-].[Cu+2] JJLJMEJHUUYSSY-UHFFFAOYSA-L 0.000 description 2
- 239000005750 Copper hydroxide Substances 0.000 description 2
- 150000001298 alcohols Chemical class 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 239000003985 ceramic capacitor Substances 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 229910001956 copper hydroxide Inorganic materials 0.000 description 2
- BERDEBHAJNAUOM-UHFFFAOYSA-N copper(I) oxide Inorganic materials [Cu]O[Cu] BERDEBHAJNAUOM-UHFFFAOYSA-N 0.000 description 2
- KRFJLUBVMFXRPN-UHFFFAOYSA-N cuprous oxide Chemical compound [O-2].[Cu+].[Cu+] KRFJLUBVMFXRPN-UHFFFAOYSA-N 0.000 description 2
- 229940112669 cuprous oxide Drugs 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 239000000945 filler Substances 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- XNGIFLGASWRNHJ-UHFFFAOYSA-N phthalic acid Chemical compound OC(=O)C1=CC=CC=C1C(O)=O XNGIFLGASWRNHJ-UHFFFAOYSA-N 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- WRIDQFICGBMAFQ-UHFFFAOYSA-N (E)-8-Octadecenoic acid Natural products CCCCCCCCCC=CCCCCCCC(O)=O WRIDQFICGBMAFQ-UHFFFAOYSA-N 0.000 description 1
- LQJBNNIYVWPHFW-UHFFFAOYSA-N 20:1omega9c fatty acid Natural products CCCCCCCCCCC=CCCCCCCCC(O)=O LQJBNNIYVWPHFW-UHFFFAOYSA-N 0.000 description 1
- QSBYPNXLFMSGKH-UHFFFAOYSA-N 9-Heptadecensaeure Natural products CCCCCCCC=CCCCCCCCC(O)=O QSBYPNXLFMSGKH-UHFFFAOYSA-N 0.000 description 1
- 239000004925 Acrylic resin Substances 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- ZQPPMHVWECSIRJ-UHFFFAOYSA-N Oleic acid Natural products CCCCCCCCC=CCCCCCCCC(O)=O ZQPPMHVWECSIRJ-UHFFFAOYSA-N 0.000 description 1
- 239000005642 Oleic acid Substances 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 150000001879 copper Chemical class 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- QXJSBBXBKPUZAA-UHFFFAOYSA-N isooleic acid Natural products CCCCCCCC=CCCCCCCCCC(O)=O QXJSBBXBKPUZAA-UHFFFAOYSA-N 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000011812 mixed powder Substances 0.000 description 1
- ZQPPMHVWECSIRJ-KTKRTIGZSA-N oleic acid Chemical compound CCCCCCCC\C=C/CCCCCCCC(O)=O ZQPPMHVWECSIRJ-KTKRTIGZSA-N 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- IHQKEDIOMGYHEB-UHFFFAOYSA-M sodium dimethylarsinate Chemical class [Na+].C[As](C)([O-])=O IHQKEDIOMGYHEB-UHFFFAOYSA-M 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
Landscapes
- Powder Metallurgy (AREA)
- Conductive Materials (AREA)
- Non-Insulated Conductors (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は，厚みが極めて薄い
箔片状の銅粒子からなる銅粉およびこれを用いた導電ペ
ーストに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper powder composed of foil-like copper particles having an extremely thin thickness, and a conductive paste using the same.
【０００２】[0002]
【従来の技術】樹脂に銅粉を分散させた導電ペースト
は，絶縁基板の意図する位置に導電回路を接合または配
属したり，チップ部品に外部電極を付与したりするのに
使用されている。最近では，積層セラミックスコンデン
サーの外部電極としても適用されるようになってきた。
後者の場合には，通常は，セラミックス素体の意図する
外部電極形成部分に導電ペーストを付着させた後，加熱
処理し，その加熱中においてペースト中のビヒクル分を
蒸発または分解除去すると共に銅粉を互いに焼結させる
ことによって外部電極が形成される。2. Description of the Related Art A conductive paste in which copper powder is dispersed in a resin is used for joining or assigning a conductive circuit to an intended position of an insulating substrate, or for providing an external electrode to a chip component. Recently, it has also come to be used as an external electrode of a laminated ceramic capacitor.
In the latter case, usually, the conductive paste is attached to the intended external electrode formation portion of the ceramic body, and then heat treatment is performed, and the vehicle component in the paste is evaporated or decomposed and removed during the heating, and the copper powder is also removed. External electrodes are formed by sintering the two together.
【０００３】このような外部電極の場合，その電極表面
を平滑にするには，導電ペースト中の銅粉が球形の粒状
のものより偏平な形をした薄片状のものの方がよい。特
に，厚みができるだけ薄くて，粒径が小さく，反りや曲
がりの少ないものであれば，それらの薄片が広面側をほ
ぼ平行にして互いに重なり合ったときに接触面積が多く
なり，焼結されたあとでも表面が極めて平滑になり，セ
ラミックス素体との接合も良好となる。この種のコンデ
ンサーは小型化が進行しており，電極部分もそれにつれ
て微小化しているので，銅薄片の広面側の長さ（長径）
があまり大きくなると，そのペーストを塗布したときに
毛羽立つような状態になりことから，長径があまり大き
くないことも要求される。In the case of such an external electrode, in order to make the surface of the electrode smooth, it is preferable that the copper powder in the conductive paste is a flat flaky one rather than a spherical granular one. In particular, if the thickness is as thin as possible, the grain size is small, and the warpage and bending are small, the contact area becomes large when the flakes overlap with each other with their broad sides substantially parallel, and after sintering, However, the surface becomes extremely smooth and the bonding with the ceramic body is also good. This type of capacitor is becoming smaller, and the electrode parts are becoming smaller accordingly, so the length (major axis) of the wide side of the copper flakes
When the paste becomes too large, the paste becomes fluffy when applied, so that it is also required that the major axis is not too large.
【０００４】従来より，偏平な銅粉として次のようなも
のが知られている。例えば特開平８−３２５６１２号公
報には，平均長径が１５μｍ以下で偏平比（長径／厚み
の比）が２０以下である鱗片状の銅粉およびその製法が
記載されている。特開平７−１１８７０１号公報には，
厚みが 0.02 〜 2.0μｍで, 表面の長寸が 0.2〜10.0μ
ｍ, 短寸が長寸以下のフレーク状金属粉末が記載されて
いる。The following are known as flat copper powders. For example, Japanese Unexamined Patent Publication No. 8-325612 describes a scaly copper powder having an average major axis of 15 μm or less and a flatness ratio (major axis / thickness ratio) of 20 or less, and a method for producing the same. Japanese Patent Laid-Open No. 7-118701 discloses
Thickness is 0.02 to 2.0 μm, and surface length is 0.2 to 10.0 μm.
m, flake-like metal powder whose short dimension is less than long dimension is described.
【０００５】[0005]
【発明が解決しようとする課題】一般に銅粒子をボール
ミルやアトライタ等を用いて機械的に偏平化しようとし
ても，銅は延伸性が高いので，摩砕されずに圧延され，
長径が大きくなる。このため，機械的な加工によって長
径を小さくしながら且つ厚みが薄い銅粉を得るのは困難
である。特開平８−３２５６１２号公報では亜鉛末との
置換反応で微細な銅粉を析出させ，この銅粉を液中で偏
平化させることを提案している。しかし，この方法でも
平均長径が１５μｍ以下で偏平比が２０以下のものが得
られるに過ぎない。すなわち，この鱗片上銅粒子の厚み
は０.７５μｍ以上であり，これより厚みの薄い鱗片状
のものは開示されていない。特開平７−１１８７０１号
公報では厚みがさらに薄いフレーク状の各種金属粉（銅
を含む）が記載されているが，それでもその厚みは０.
０２〜２.０μｍの範囲にある。Generally, when copper particles are mechanically flattened by using a ball mill, an attritor, etc., since copper has high extensibility, it is rolled without being ground,
The major axis becomes large. For this reason, it is difficult to obtain copper powder having a small major axis and a small thickness by mechanical processing. Japanese Unexamined Patent Publication No. 8-325612 proposes to deposit fine copper powder by a substitution reaction with zinc dust and flatten the copper powder in a liquid. However, even with this method, an average major axis of 15 μm or less and an aspect ratio of 20 or less can be obtained. That is, the thickness of the copper particles on scales is 0.75 μm or more, and scale-like ones thinner than this are not disclosed. Japanese Patent Application Laid-Open No. 7-118701 describes various flaky metal powders (including copper) having a smaller thickness, but the thickness thereof is still less.
It is in the range of 02 to 2.0 μm.
【０００６】したがって，本発明は，積層セラミックス
コンデンサーの外部電極を形成する導電ペーストに好適
な銅粉，すなわち，小さな粒径を有し且つ従来のものよ
りも一層厚みが薄い箔片状の銅粉を得ることを目的とし
たものである。Therefore, the present invention provides a copper powder suitable for a conductive paste forming an external electrode of a multilayer ceramic capacitor, that is, a foil-shaped copper powder having a smaller particle size and a thinner thickness than the conventional one. The purpose is to obtain.
【０００７】[0007]
【課題を解決するための手段】前記の課題を解決すべく
本発明者らは鋭意研究を重ねたところ，湿式メディアミ
ルを用いて適正な条件で銅粉を圧延すると，長径および
粒径は一定以上には大きくならずに厚みだけを薄くでき
ることが判明した。すなわち本発明によれば，厚さが２
０ｎｍ未満で平均長径が４０μｍ以下の箔片状の銅粒子
からなり，下記に定義するＤ１０，Ｄ５０およびＤ９０
の値の間で下式(1)に従うＡ値が１以上の粒度分布を有
する箔片状銅粉を提供する。この箔片状銅粉はＢＥＴ法
で測定した比表面積が，好ましくは 2.0〜5.0 ｍ2/ｇの
範囲である。
Ａ値＝（Ｄ９０−Ｄ１０）／Ｄ５０・・・(1)
ただし，Ｄ１０，Ｄ５０およびＤ９０は，横軸に粒径Ｄ
（μｍ），縦軸にＱ％（その粒径以下の粒子が存在する
割合・単位は粒子の容積％）をとった累積粒度曲線にお
いて，Ｑ％＝１０％，５０％および９０％に対応するそ
れぞれの粒径Ｄの値を言う。[Means for Solving the Problems] The inventors of the present invention have conducted extensive studies to solve the above problems. As a result, when copper powder is rolled under appropriate conditions using a wet media mill, the long diameter and the particle diameter are constant. It has been found that only the thickness can be reduced without increasing the above. That is, according to the present invention, the thickness is 2
D10, D50 and D90 defined below, consisting of foil-like copper particles with an average major axis of less than 0 nm and 40 μm or less
There is provided a foil flaky copper powder having a particle size distribution with an A value of 1 or more according to the following formula (1). The specific surface area of this foil-shaped copper powder measured by the BET method is preferably in the range of 2.0 to 5.0 m 2 / g. A value = (D90−D10) / D50 (1) where D10, D50 and D90 are the particle size D on the horizontal axis.
(Μm), and the vertical axis corresponds to Q% = 10%, 50%, and 90% in the cumulative particle size curve in which Q% (the ratio and unit of particles having a particle size equal to or smaller than the particle size is the volume% of the particle) is taken. The value of each particle size D is referred to.
【０００８】[0008]
【発明の実施の形態】導電ペースト用の銅粉を製造する
には，粒径制御や純度の点，さらには製造性等の点から
湿式還元法を採用するのが便宜である。湿式還元法は，
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，この水酸化銅を亜酸化銅に液中で一次還元し，得ら
れた亜酸化銅を金属銅に液中で二次還元することを要旨
とする方法であり，粒径の揃った球状銅粉を得るのに適
している。BEST MODE FOR CARRYING OUT THE INVENTION In order to produce copper powder for a conductive paste, it is convenient to employ a wet reduction method from the standpoints of particle size control, purity, and manufacturability. Wet reduction method
An aqueous solution of a copper salt is reacted with an alkaline agent to precipitate copper hydroxide, and the copper hydroxide is first reduced to cuprous oxide in the liquid, and the obtained cuprous oxide is secondarily reduced to metallic copper in the liquid. This is a method based on this point, and is suitable for obtaining spherical copper powder with a uniform particle size.
【０００９】このような球状銅粉を，ボールミルや振動
ミルを用いて，ミル内に装填したメディア（セラミック
やガラスなどの球体）によって偏平な形に変形（圧延）
しようとすると，初期粒径がどのような場合でも，薄く
加工されると，それらが重なりあって再び薄く加工され
るという現象が繰り返されるので，長径は大きくなる
が，厚みは或る値以上は薄くならない。偏平な粒子同士
が重なって一体的な粒子に圧延されるこのような現象は
温度が高くなると加速される。通常のボールミルや振動
ミルでは加工に伴って発生する熱を発散させ難いので，
この点でも不利である。[0009] Such spherical copper powder is deformed (rolled) into a flat shape by a medium (sphere such as ceramic or glass) loaded in the mill using a ball mill or a vibration mill.
Attempting to do so, no matter what the initial grain size is, if thinly machined, the phenomenon of overlapping and again thinning is repeated, so the major axis becomes large, but the thickness exceeds a certain value. It doesn't become thin. Such a phenomenon in which flat particles are overlapped with each other and rolled into an integral particle is accelerated as the temperature rises. It is difficult to dissipate the heat generated by machining with ordinary ball mills and vibration mills.
This is also a disadvantage.
【００１０】この点に着目し，本発明者らは蒸発熱によ
って熱を発散させるのに適した液体（沸点の低いアルコ
ール等）の存在下で銅粉を偏平な形に加工することを試
みた。また，粒子の分散を促進するために各種の分散剤
も使用して，湿式条件下でミル内に装填したメディア
（セラミックやガラスなどの球体）によって球状銅粉を
摩砕することを試みた。その結果，平均粒径が１〜６μ
ｍの範囲にある球状銅粉を，粒径が１〜５ｍｍ好ましく
は１.３〜２.５ｍｍのセラミックボールを装填したミル
（サンドグラインダ）にアルコール類と共に装填し，分
散剤（例えばステアリン酸）を添加して該銅粉を加工し
た場合には，薄く加工されても重なり合って一体化する
ことが抑制され，厚みは処理時間に伴ってどんどん薄く
なり，一定の長径になると破断が起きて長径が大きくな
ることも抑制できることがわかった。Focusing on this point, the present inventors attempted to process the copper powder into a flat shape in the presence of a liquid (such as alcohol having a low boiling point) suitable for radiating heat by the heat of evaporation. . We also tried to grind spherical copper powder with media (ceramics, glass, etc.) loaded in the mill under wet conditions, using various dispersants to accelerate the dispersion of particles. As a result, the average particle size is 1-6μ
The spherical copper powder in the range of m is loaded with alcohols into a mill (sand grinder) loaded with ceramic balls having a particle size of 1 to 5 mm, preferably 1.3 to 2.5 mm, and a dispersant (for example, stearic acid). When the copper powder is processed by adding, it is suppressed that the copper powder overlaps and integrates even if it is processed thinly. It has been found that it is possible to suppress an increase in the.
【００１１】蒸発し易い液体としては一般的なアルコー
ル類が適しており，例えばエタノール，メタノール，イ
ソプロパノールを使用することにより，これらの蒸発時
の潜熱によって加工時に発生する熱を効率よく抜熱でき
る。また，メディアボールとしては，衝撃に耐えるセラ
ミックス例えばアルミナやジルコニアボールが適してい
る。分散剤としては各種の界面活性剤が使用できるが，
使用する蒸発性液体に良好に溶解するものがよく，例え
ばオレイン酸，フタル酸，ステアリン酸等が使用でき
る。As the liquid that easily evaporates, general alcohols are suitable. For example, by using ethanol, methanol, and isopropanol, the heat generated during processing due to the latent heat during evaporation can be efficiently removed. Further, as the media balls, ceramics that withstand impact, such as alumina and zirconia balls, are suitable. Although various surfactants can be used as the dispersant,
It is preferably one that is well soluble in the evaporative liquid used, and for example oleic acid, phthalic acid, stearic acid, etc. can be used.
【００１２】図１と図２は，そのようにして得られた本
発明に従う箔片状の銅粉の電子顕微鏡写真（ＳＥＭ）の
一例を示したものである。図１と図２は倍率が異なるだ
けで，同一の箔片状の銅粉である。この銅粉は，長径が
平均約３０μｍ，厚みが平均約１５ｎｍの粒子からな
る。すなわち，厚みは従来の限界を超えて２０ｎｍ以下
であり，長径も３０μｍ以下と小さい。そして，各粒子
は一様に分散しており，粒子同士の凝集は見られない。
また，各粒子には曲がりや反りも少なく平たんな箔片状
をしている。FIG. 1 and FIG. 2 show examples of electron micrographs (SEM) of the thus obtained foil-shaped copper powder according to the present invention. 1 and 2 are the same foil-shaped copper powder, except for the magnification. The copper powder is composed of particles having an average major axis of about 30 μm and an average thickness of about 15 nm. That is, the thickness exceeds the conventional limit and is 20 nm or less, and the major axis is as small as 30 μm or less. Then, each particle is uniformly dispersed, and no agglomeration of particles is observed.
In addition, each particle has a flat foil shape with little bending or warping.
【００１３】このようにして本発明によると，厚さが２
０ｎｍ未満の箔片状の粒子からなり，平均長径は大きく
ても４０μｍまで，好ましくは２０μｍまで，さらに好
ましくは１０μｍまで，平均粒径が４μｍ以上好ましく
は１０μｍ以下，好ましくは６μｍ以下の箔片状銅粉が
得られ，このものは，導電ペースト用のフイラーとして
使用すると，粒子同士の接触面積が極めて大きく且つ互
いに重なり合った状態で塗布されるので，導電性の点で
も表面平滑さの点でも従来のものにはない良好な導電回
路や外部電極を形成することができる。このものを樹脂
に分散させるさいに，本発明に従う箔片状銅粉だけを樹
脂に分散させてもよいが，球状銅粉と適切な割合で混合
して樹脂に分散させてもよい。また，粒度分布が異なる
箔片状銅粉を数種類製造し，それらを適切に混合して樹
脂に分散させてもよい。Thus, according to the present invention, the thickness is 2
Foil-like particles consisting of foil-like particles of less than 0 nm and having an average major axis of at most 40 μm, preferably up to 20 μm, more preferably up to 10 μm, and an average particle size of 4 μm or more, preferably 10 μm or less, preferably 6 μm or less. Copper powder is obtained, and when used as a filler for conductive paste, the contact areas between particles are extremely large and they are applied in a state of overlapping with each other. It is possible to form excellent conductive circuits and external electrodes that cannot be found in other products. When this is dispersed in the resin, only the foil flaky copper powder according to the present invention may be dispersed in the resin, or spherical copper powder may be mixed in an appropriate ratio and dispersed in the resin. Also, several kinds of foil-shaped copper powders having different particle size distributions may be produced, appropriately mixed and dispersed in the resin.
【００１４】本発明に従う箔片状の銅粉は，粒度分布の
測定により，前記(1) 式のＡ値が１以上を示す点でも特
異なものである。Ａ値が１以上であることは，長径の大
きなものから小さなものまで一様に箔片状である粒子が
広がりをもって分布していることを示しており，このた
め，箔片状であっても充填性がよくなる。また，本発明
に従う箔片状の銅粉は前記(1) 式のＤ５０の値が４.９
μｍ以上であるのが好ましい。比表面積については，Ｂ
ＥＴ法で２.０ｍ2/ｇ以上である。一般に厚みが薄くな
るほど比表面積は増加するが，長径が４０μｍを超える
ような大きな粒子とはなり難いので，比表面積は通常は
５.０ｍ2/ｇ以下となる。比表面積は厚さの指標ともな
り得るので，箔片状粒子の厚さの制御を行う場合には
（その制御は前記の湿式加工法における処理時間の調節
によって行うことができる），厚みの指標として比表面
積を用いるのが便利である。The foil-shaped copper powder according to the present invention is also unique in that the A value of the above formula (1) shows 1 or more when the particle size distribution is measured. The A value of 1 or more indicates that the particles in the form of foil are uniformly distributed from the one with a large major diameter to the one with a small major diameter. The filling property is improved. Further, the foil-shaped copper powder according to the present invention has a value of D50 of the above formula (1) of 4.9.
It is preferably at least μm. For specific surface area, see B
It is 2.0 m 2 / g or more by the ET method. Generally, the thinner the thickness is, the larger the specific surface area is, but it is difficult to obtain large particles having a major axis of more than 40 μm, and therefore the specific surface area is usually 5.0 m 2 / g or less. Since the specific surface area can also be an index of the thickness, when controlling the thickness of the foil-shaped particles (the control can be performed by adjusting the processing time in the above-mentioned wet processing method), the index of the thickness It is convenient to use the specific surface area as.
【００１５】[0015]
【実施例】〔実施例１〕湿式還元法によって製造された
平均粒径１.４μｍの銅粉を，２.５ｍｍ径のジルコニア
ボールと共に，アイメックス株式会社製の容積が１５Ｌ
タイプの縦型サンドグラインダに装填し，分散剤として
のステアリン酸を銅粉に対して１wt％の割合で２−プロ
パノールに添加し，この分散剤を溶解したアルコール溶
液を該サンドグラインダに銅粉に対して初期重量１１５
wt％の割合で装填し，処理を開始し，１２０分間連続し
て処理した。得られた銅粉を回収し，平均長径，粒度分
布，ＢＥＴ法による比表面積を測定した。その結果を表
１に示した。EXAMPLES Example 1 Copper powder having an average particle size of 1.4 μm manufactured by a wet reduction method was used together with zirconia balls having a diameter of 2.5 mm and a volume of 15 L manufactured by IMEX Co., Ltd.
Type vertical sand grinder, stearic acid as a dispersant was added to 2-propanol at a ratio of 1 wt% with respect to copper powder, and an alcohol solution in which this dispersant was dissolved was added to the sand grinder to form copper powder. Initial weight 115
It was loaded at a wt% ratio, the treatment was started, and the treatment was continued for 120 minutes. The obtained copper powder was collected, and the average major axis, particle size distribution, and specific surface area by the BET method were measured. The results are shown in Table 1.
【００１６】粒度分布はベックマンコールター社製の粒
度分布測定装置（ＬＳ２３０）を用いて測定した。The particle size distribution was measured using a particle size distribution measuring device (LS230) manufactured by Beckman Coulter.
【００１７】さらに，得られた箔片状銅粉に対し，平均
粒径が３μｍの球状銅粉を８０重量％の割合で混合し，
この混合粉をアクリル樹脂中に８９重量％の量で配合し
混練して導電ペーストを得た。この導電ペーストをガラ
スシートに塗布し，その塗膜をガラスシートと共に窒素
ガス中で９００℃に分間保持する加熱処理を行って該塗
膜を焼結した。得られた焼成膜の表面粗度を測定し，表
面粗度Ｒａが１.５μｍ以下のものを○印，１.５μｍ超
え〜２.５μｍ未満のものを△，２.５μｍ以上のものを
×印として三段階評価を行った。その結果も表１に示し
た。Further, 80% by weight of spherical copper powder having an average particle diameter of 3 μm was mixed with the obtained foil flaky copper powder,
This mixed powder was mixed in acrylic resin in an amount of 89% by weight and kneaded to obtain a conductive paste. This conductive paste was applied to a glass sheet, and the coating film was sintered together with the glass sheet by heating it at 900 ° C. for one minute in nitrogen gas to sinter the coating film. The surface roughness of the obtained fired film was measured, and the surface roughness Ra of 1.5 μm or less was marked with “◯”, the surface roughness Ra of more than 1.5 μm to less than 2.5 μm was “△”, and the surface roughness Ra of 2.5 μm or more was ×. Three-level evaluation was performed as a mark. The results are also shown in Table 1.
【００１８】〔実施例２〕処理時間を１８０分間とした
以外は実施例１を繰り返した。得られた箔片状銅粉につ
いて実施例１と同様の測定を行うと共に，実施例１と同
様に導電ペーストの評価を行った。それらの結果を表１
に示した。Example 2 Example 1 was repeated except that the treatment time was 180 minutes. The same measurement as in Example 1 was performed on the obtained foil-shaped copper powder, and the conductive paste was evaluated in the same manner as in Example 1. The results are shown in Table 1.
It was shown to.
【００１９】〔実施例３〕処理時間を２１０分間とした
以外は実施例１を繰り返した。得られた箔片状銅粉につ
いて実施例１と同様の測定を行うと共に，実施例１と同
様に導電ペーストの評価を行った。それらの結果を表１
に示した。Example 3 Example 1 was repeated except that the treatment time was 210 minutes. The same measurement as in Example 1 was performed on the obtained foil-shaped copper powder, and the conductive paste was evaluated in the same manner as in Example 1. The results are shown in Table 1.
It was shown to.
【００２０】〔比較例１〕分散剤としてのステアリン酸
を銅粉に対して１wt％の割合で直接添加したが，２−プ
ロパノールは使用しなかった以外は，実施例１を繰り返
した。得られた箔片状銅粉について実施例１と同様の測
定を行うと共に，実施例１と同様に導電ペーストの評価
を行った。それらの結果を表１に示した。Comparative Example 1 Example 1 was repeated except that stearic acid as a dispersant was directly added in a proportion of 1 wt% with respect to the copper powder, but 2-propanol was not used. The same measurement as in Example 1 was performed on the obtained foil-shaped copper powder, and the conductive paste was evaluated in the same manner as in Example 1. The results are shown in Table 1.
【００２１】〔比較例２〕処理時間を６０分間の短時間
とした以外は実施例１を繰り返した。得られた箔片状銅
粉について実施例１と同様の測定を行うと共に，実施例
１と同様に導電ペーストの評価を行った。それらの結果
を表１に示した。Comparative Example 2 Example 1 was repeated except that the treatment time was shortened to 60 minutes. The same measurement as in Example 1 was performed on the obtained foil-shaped copper powder, and the conductive paste was evaluated in the same manner as in Example 1. The results are shown in Table 1.
【００２２】[0022]
【表１】 [Table 1]
【００２３】表１の結果から，実施例１の湿式処理条件
下では，処理時間を長くすると，長径は大きくならずに
比表面積が大きくなることがわかる。すなわち，処理時
間を長くすると箔片状粒子の厚みはどんどん薄くなって
ゆき，所定の長径になると粒子が摩断される。そして，
厚みが２０ｎｍ以下の微細な銅粒子が得られることがわ
かる。このものは，導電ペーストで厚膜としたときにそ
の焼成品の表面状態が平滑になる。これに対して，厚み
が大きくて且つＡ値が１以下の比較例１のもの，比表面
積が２.０ｇ/cm3以下の比較例２のものは，いずれも導
電ペーストで厚膜としたときにその焼成品の表面状態が
平滑にならない。From the results shown in Table 1, it can be seen that under the wet treatment conditions of Example 1, when the treatment time is increased, the major axis is increased and the specific surface area is increased. That is, as the treatment time is lengthened, the thickness of the foil-like particles becomes thinner and thinner, and the particles become worn when the length becomes a predetermined major axis. And
It can be seen that fine copper particles having a thickness of 20 nm or less can be obtained. In this product, when the conductive paste is formed into a thick film, the surface condition of the baked product becomes smooth. On the other hand, Comparative Example 1 having a large thickness and an A value of 1 or less and Comparative Example 2 having a specific surface area of 2.0 g / cm 3 or less were both formed with a thick film of conductive paste. Moreover, the surface condition of the baked product is not smooth.
【００２４】[0024]
【発明の効果】以上説明したように，本発明によると，
厚みが２０ｎｍ以下と極めて薄く，粒径が小さな導電ペ
ーストのフイラーとして好適な箔片状の銅粉が得られ
る。As described above, according to the present invention,
A foil-like copper powder suitable for a filler of a conductive paste having a very small thickness of 20 nm or less and a small particle size can be obtained.
【図１】本発明に従う箔片状銅粉の一例を示す電子顕微
鏡写真である。FIG. 1 is an electron micrograph showing an example of a foil flaky copper powder according to the present invention.
【図２】図１の銅粉を倍率を変えて撮影した電子顕微鏡
写真である。2 is an electron micrograph of the copper powder of FIG. 1 taken at different magnifications.
───────────────────────────────────────────────────── フロントページの続き Ｆターム(参考） 4K018 AA03 BA02 BB01 BB03 BC08 BC12 BD04 KA33 5G301 DA06 DA42 DD01 ─────────────────────────────────────────────────── ─── Continued front page F term (reference) 4K018 AA03 BA02 BB01 BB03 BC08 BC12 BD04 KA33 5G301 DA06 DA42 DD01
Claims (5)
０μｍ以下の箔片状の銅粒子からなり，下記に定義する
Ｄ１０，Ｄ５０およびＤ９０の値の間で下式(1)に従う
Ａ値が１以上の粒度分布を有する箔片状銅粉。 Ａ値＝（Ｄ９０−Ｄ１０）／Ｄ５０・・・(1) ただし，Ｄ１０，Ｄ５０およびＤ９０は，横軸に粒径Ｄ
（μｍ），縦軸にＱ％（その粒径以下の粒子が存在する
割合・単位は粒子の容積％）をとった累積粒度曲線にお
いて，Ｑ％＝１０％，５０％および９０％に対応するそ
れぞれの粒径Ｄの値を言う。1. An average thickness of less than 20 nm and an average major axis of 4
A foil-like copper powder consisting of foil-like copper particles of 0 μm or less and having a particle size distribution with an A value of 1 or more according to the following formula (1) among the values of D10, D50 and D90 defined below. A value = (D90−D10) / D50 (1) where D10, D50 and D90 are the particle size D on the horizontal axis.
(Μm), and the vertical axis corresponds to Q% = 10%, 50%, and 90% in the cumulative particle size curve in which Q% (the ratio and unit of particles having a particle size equal to or smaller than the particle size is the volume% of the particle) is taken. The value of each particle size D is referred to.
0 ｍ2/ｇである請求項１に記載の箔片状銅粉。2. The specific surface area measured by the BET method is 2.0 to 5.
The foil-shaped copper powder according to claim 1, which is 0 m 2 / g.
を混合してなる銅粉。3. A copper powder obtained by mixing spherical copper powder with the foil-shaped copper powder according to claim 1.
散させてなる導電ペースト。4. A conductive paste obtained by dispersing the foil-shaped copper powder according to claim 1 in a resin.
項１に記載の箔片状銅粉を樹脂に分散させてなる導電ペ
ースト。5. A conductive paste obtained by dispersing spherical copper powder having an average particle size of 5 μm or less and the foil-shaped copper powder according to claim 1 in a resin.
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| WO2004048017A1 (en) * | 2002-11-22 | 2004-06-10 | Mitsui Mining & Smelting Co.,Ltd. | Copper flake powder, method for producing copper flake powder, and conductive paste using copper flake powder |
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| WO2004048017A1 (en) * | 2002-11-22 | 2004-06-10 | Mitsui Mining & Smelting Co.,Ltd. | Copper flake powder, method for producing copper flake powder, and conductive paste using copper flake powder |
| JP2006118032A (en) * | 2004-10-25 | 2006-05-11 | Mitsui Mining & Smelting Co Ltd | Flake copper powder provided with copper oxide coat layer, method for producing flake copper powder provided with copper oxide coat layer and conductive slurry comprising flake copper powder provided with copper oxide coat layer |
| JP2008174698A (en) * | 2007-01-19 | 2008-07-31 | Nippon Koken Kogyo Kk | Smooth flaky powder, high-brightness pigment, and method for producing the same |
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| JP2015034309A (en) * | 2013-08-07 | 2015-02-19 | 三井金属鉱業株式会社 | Composite copper particles and method for manufacturing the same |
| JP2017106047A (en) * | 2015-12-07 | 2017-06-15 | 山陽特殊製鋼株式会社 | Powder for conductive filler |
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