JP4728665B2 - Conductive fine particles, method for producing conductive fine particles, and anisotropic conductive material - Google Patents

Conductive fine particles, method for producing conductive fine particles, and anisotropic conductive material Download PDF

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JP4728665B2
JP4728665B2 JP2005061349A JP2005061349A JP4728665B2 JP 4728665 B2 JP4728665 B2 JP 4728665B2 JP 2005061349 A JP2005061349 A JP 2005061349A JP 2005061349 A JP2005061349 A JP 2005061349A JP 4728665 B2 JP4728665 B2 JP 4728665B2
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alloy plating
fine particles
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nickel
plating film
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JP2006052460A (en
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敬士 久保田
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Sekisui Chemical Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
    • C23C18/1601—Process or apparatus
    • C23C18/1633—Process of electroless plating
    • C23C18/1635—Composition of the substrate
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
    • C23C18/31—Coating with metals
    • C23C18/32—Coating with nickel, cobalt or mixtures thereof with phosphorus or boron
    • C23C18/34—Coating with nickel, cobalt or mixtures thereof with phosphorus or boron using reducing agents
    • C23C18/36—Coating with nickel, cobalt or mixtures thereof with phosphorus or boron using reducing agents using hypophosphites

Description

本発明は、導電性微粒子、該導電性微粒子の製造方法、及び該導電性微粒子を用いた異方性導電材料に関する。   The present invention relates to conductive fine particles, a method for producing the conductive fine particles, and an anisotropic conductive material using the conductive fine particles.

従来、導電性微粒子として金、銀、ニッケル等を粒状にした金属粒子が用いられてきたが、比重が大きく、形状が一定でないため、バインダー樹脂中に均一に分散しないことがあり、異方性導電材料の導電性にムラを生じさせる原因となっていた。   Conventionally, metallic particles made of gold, silver, nickel, etc., have been used as conductive fine particles, but the specific gravity is large and the shape is not constant. This was a cause of unevenness in the conductivity of the conductive material.

これに対して、芯材粒子としてガラスビーズ、グラスファイバー、プラスチックボール等の非導電性粒子の表面にニッケル等の金属によるメッキを施した導電性微粒子が報告されている。例えば、特許文献１には、実質的に球状な樹脂粉末粒子を無電解ニッケルメッキ法により金属被覆を形成した導電性無電解メッキ粉体が開示されている。   In contrast, conductive fine particles in which the surface of non-conductive particles such as glass beads, glass fibers, and plastic balls are plated with a metal such as nickel have been reported as core material particles. For example, Patent Document 1 discloses a conductive electroless plating powder obtained by forming a metal coating on substantially spherical resin powder particles by an electroless nickel plating method.

しかしながら、これらの無電解ニッケルメッキ法による金属被膜では、ニッケル被膜中にリンを含有するため純ニッケル金属と比較して導電性が低下するだけでなく、ニッケル被膜中のリン含有率が高いと、ニッケル被膜の導電性が更に悪化する傾向にある。
また、これらの無電解ニッケルメッキ法は、芯材粒子自体の表面積が大きく、凝集力が大きいため、一定ｐＨで分散液にニッケルメッキ液を構成するニッケル塩溶液と次亜リン酸ナトリウム等の還元剤溶液とを少量ずつ添加する方法ではメッキ反応速度を精密に制御することが困難であり、導電性微粒子の凝集性を抑えることが十分ではない。 However, in these metal films by the electroless nickel plating method, since the nickel film contains phosphorus, not only does the conductivity decrease as compared to pure nickel metal, but the phosphorus content in the nickel film is high, The conductivity of the nickel coating tends to be further deteriorated.
In addition, since these electroless nickel plating methods have a large surface area and large cohesive force, the nickel salt solution and nickel hypophosphite that constitute the nickel plating solution in the dispersion at a constant pH are reduced. In the method of adding the agent solution little by little, it is difficult to precisely control the plating reaction rate, and it is not sufficient to suppress the aggregation of the conductive fine particles.

一方、特許文献２には、ニッケル又はコバルトからなり、１．５〜４重量％のリンを含有する金属被覆層を樹脂微粒子の表面に設けた導電性微粒子が開示されている。
更に、特許文献３には、導電性が損なわれないように、ニッケル被膜中のリン含有量をニッケル被膜の厚さ方向で異ならせ、芯材粒子側からニッケル被膜表面側に漸減しているニッケルメッキ粒子が開示されている。 On the other hand, Patent Document 2 discloses conductive fine particles made of nickel or cobalt and provided with a metal coating layer containing 1.5 to 4% by weight of phosphorus on the surface of resin fine particles.
Further, in Patent Document 3, the nickel content is gradually reduced from the core material particle side to the nickel coating surface side by varying the phosphorus content in the nickel coating in the thickness direction of the nickel coating so as not to impair the conductivity. Plating particles are disclosed.

特開平８−３１１６５５号公報JP-A-8-31655 特許第２５０７３８１号公報Japanese Patent No. 2507381 特開２００３−３４８７９号公報JP 2003-34879 A

特許文献２の導電性微粒子は導電性に優れているが、金属被覆層の可とう性が十分でなく芯材粒子との密着性が不十分であることから、近年の電子機器の急速な進歩に伴う電気的接続の更なる信頼性向上に対応できないという問題がある。   Although the conductive fine particles of Patent Document 2 are excellent in electrical conductivity, the rapid progress of recent electronic devices since the flexibility of the metal coating layer is insufficient and the adhesion with the core particles is insufficient. There is a problem that it is impossible to cope with further improvement in the reliability of electrical connection.

また、特許文献３のニッケルメッキ粒子を製造する方法では、リン濃度を下げるため、反応速度を徐々に速めていることから浴分解を起こしやすく、浴管理がし難い等の問題がある。また、ニッケル被膜表面のリン含有量が低いためメッキ被膜が磁性性質を帯び、ニッケル被膜表面付近の反応にて凝集を生じ易い等の問題がある。
更に、特許文献３のニッケルメッキ粒子は、メッキ被膜表面側のリン濃度を低くすることにより導電性を高めているが、それでも純ニッケル金属には劣り、導電性を全面的に改善する程の効果は得られていない。 In addition, the method for producing nickel-plated particles of Patent Document 3 has problems such as that the reaction rate is gradually increased to reduce the phosphorus concentration, so that bath decomposition is likely to occur, and bath management is difficult. Moreover, since the phosphorus content on the surface of the nickel coating is low, the plating coating has magnetic properties, and there is a problem that aggregation is likely to occur due to a reaction near the surface of the nickel coating.
Furthermore, the nickel-plated particles of Patent Document 3 have improved conductivity by lowering the phosphorus concentration on the surface of the plating film, but they are still inferior to pure nickel metal and have the effect of improving the overall conductivity. Is not obtained.

本発明は、上記現状に鑑み、優れた導電性を有し、更に、芯材粒子との密着性が高くかつ凝集性が少ない導電性微粒子、メッキ浴の安定性が高い該導電性微粒子の製造方法、及び該導電性微粒子を用いた異方性導電材料を提供することを目的とする。   In view of the above situation, the present invention provides conductive fine particles having excellent conductivity, and having high adhesion to core particles and low cohesiveness, and high stability of the plating bath. It is an object to provide a method and an anisotropic conductive material using the conductive fine particles.

上記目的を達成するために請求項１記載の発明は、芯材粒子の表面に無電解メッキ法によりニッケル、銅、及びリンを含有する合金メッキ被膜が形成されている導電性微粒子を提供する。   In order to achieve the above object, the invention described in claim 1 provides conductive fine particles in which an alloy plating film containing nickel, copper and phosphorus is formed on the surface of core material particles by electroless plating.

また、請求項２記載の発明は、合金メッキ被膜中の厚さ方向のリン含有量が、芯材粒子側よりも合金メッキ被膜表面側で少ない請求項１記載の導電性微粒子を提供する。   The invention according to claim 2 provides the conductive fine particles according to claim 1, wherein the phosphorus content in the thickness direction in the alloy plating film is smaller on the surface of the alloy plating film than on the core material particle side.

また、請求項３記載の発明は、合金メッキ被膜中の厚さ方向において、芯材粒子側から２０％以下の領域でニッケル、及びリンを含有し、合金メッキ被膜表面側から８０％以下の領域でニッケル、銅、及びリンを含有する請求項１又は２記載の導電性微粒子を提供する。   The invention according to claim 3 contains nickel and phosphorus in a region of 20% or less from the core particle side in the thickness direction in the alloy plating film, and a region of 80% or less from the surface of the alloy plating film. The conductive fine particles according to claim 1 or 2, which contain nickel, copper, and phosphorus.

また、請求項４記載の発明は、合金メッキ被膜中の厚さ方向において、芯材粒子側から２０％以下の領域で合金メッキ組成中に８〜１５重量％のリンを含有し、合金メッキ被膜表面側から８０％以下の領域で合金メッキ組成中に０．０５〜５重量％のリンを含有する請求項１〜３のいずれか１項に記載の導電性微粒子を提供する。   According to a fourth aspect of the present invention, the alloy plating film contains 8 to 15% by weight of phosphorus in the alloy plating composition in a region of 20% or less from the core particle side in the thickness direction in the alloy plating film. The conductive fine particles according to any one of claims 1 to 3, which contain 0.05 to 5% by weight of phosphorus in the alloy plating composition in a region of 80% or less from the surface side.

また、請求項５記載の発明は、合金メッキ被膜中の厚さ方向において、合金メッキ被膜表面側から８０％以下の領域で合金メッキ組成中に０．５〜９０重量％の銅を含有する請求項１〜４のいずれか１項に記載の導電性微粒子を提供する。   Further, the invention according to claim 5 contains 0.5 to 90% by weight of copper in the alloy plating composition in the region of 80% or less from the surface of the alloy plating film in the thickness direction in the alloy plating film. Item 5. The conductive fine particle according to any one of Items 1 to 4.

また、請求項６記載の発明は、合金メッキ被膜中の厚さ方向において、芯材粒子側から２０％以下の領域で合金メッキ組成中に８５〜９２重量％のニッケルを含有し、合金メッキ被膜表面側から８０％以下の領域で合金メッキ組成中に５〜９９．４５重量％のニッケルを含有する請求項１〜５のいずれか１項に記載の導電性微粒子を提供する。   According to a sixth aspect of the present invention, the alloy plating film contains 85 to 92% by weight of nickel in the alloy plating composition in a region of 20% or less from the core particle side in the thickness direction in the alloy plating film. The conductive fine particles according to any one of claims 1 to 5, which contain 5 to 99.45 wt% of nickel in the alloy plating composition in an area of 80% or less from the surface side.

また、請求項７記載の発明は、更に、合金メッキ被膜の表面に金被膜が形成されている請求項１〜６のいずれか１項に記載の導電性微粒子を提供する。   The invention according to claim 7 further provides the conductive fine particles according to any one of claims 1 to 6, wherein a gold film is formed on the surface of the alloy plating film.

また、請求項８記載の発明は、金属触媒を担持させた芯材粒子の水性懸濁液に、ニッケル塩、リン系還元剤、及びｐＨ調整剤を含むメッキ液を添加して初期無電解メッキ反応を行い、その後、ニッケル塩、銅塩、リン系還元剤、及びｐＨ調整剤を含むメッキ液を添加して後期無電解メッキ反応を行う請求項１〜７のいずれか１項に記載の導電性微粒子の製造方法を提供する。   The invention according to claim 8 is directed to initial electroless plating by adding a plating solution containing a nickel salt, a phosphorus-based reducing agent, and a pH adjusting agent to an aqueous suspension of core material particles supporting a metal catalyst. The electroconductivity according to any one of claims 1 to 7, wherein the electroless plating reaction is performed by adding a plating solution containing a nickel salt, a copper salt, a phosphorus reducing agent, and a pH adjuster after the reaction. A method for producing conductive fine particles is provided.

また、請求項９記載の発明は、請求項１〜７のいずれか１項に記載の導電性微粒子が樹脂バインダーに分散されてなる異方性導電材料を提供する。   The invention according to claim 9 provides an anisotropic conductive material in which the conductive fine particles according to any one of claims 1 to 7 are dispersed in a resin binder.

以下、本発明の詳細を説明する。
本発明の導電性微粒子は、芯材粒子の表面に無電解メッキ法によりニッケル、銅、及びリンを含有する合金メッキ被膜が形成されているものである。
合金メッキ被膜が銅を含有しているため、ニッケルとリンとを含有したメッキ被膜や純ニッケル金属に比べ、優れた導電性を有するものとなる。 Details of the present invention will be described below.
In the conductive fine particles of the present invention, an alloy plating film containing nickel, copper, and phosphorus is formed on the surface of the core material particles by an electroless plating method.
Since the alloy plating film contains copper, it has superior conductivity as compared with a plating film containing nickel and phosphorus or pure nickel metal.

本発明における、ニッケル、銅、及びリンを含有する合金メッキ被膜を形成する方法としては特に限定されず、例えば、無電解ニッケルメッキを行う際に、ニッケル塩、銅塩、及びリン系還元剤等を用いる方法等が挙げられる。   The method for forming an alloy plating film containing nickel, copper, and phosphorus in the present invention is not particularly limited. For example, when performing electroless nickel plating, nickel salt, copper salt, phosphorus-based reducing agent, etc. And the like.

本発明の導電性微粒子は、合金メッキ被膜中の厚さ方向のリン含有量が、芯材粒子側よりも合金メッキ被膜表面側で少ないことが好ましい。
合金メッキ被膜中の厚さ方向のリン含有量が、芯材粒子側では比較的多いことにより、合金メッキ被膜と芯材粒子との密着性が良好となり、合金メッキ被膜表面側では比較的少ないことにより、合金メッキ被膜の導電性が良好となる。 In the conductive fine particles of the present invention, the phosphorus content in the thickness direction in the alloy plating film is preferably smaller on the surface of the alloy plating film than on the core material particle side.
The phosphorus content in the thickness direction in the alloy plating film is relatively high on the core particle side, so that the adhesion between the alloy plating film and the core material particle is good, and it is relatively low on the alloy plating film surface side. As a result, the conductivity of the alloy plating film is improved.

上記の、合金メッキ被膜中の厚さ方向のリン含有量が、芯材粒子側よりも合金メッキ被膜表面側で少ない導電性微粒子を製造する方法としては特に限定されず、例えば、無電解ニッケルメッキにおいて、ｐＨを順次高くし、ニッケルメッキ反応の速度を速めていく方法（ｐＨ上昇法）；メッキ温度を順次高くする方法；メッキ液中の還元剤の濃度を順次高くする方法；無電解ニッケルメッキの初期反応ではニッケル塩、及びリン系還元剤を含むメッキ液を用い、後期反応では銅塩を加えたニッケル塩、及びリン系還元剤を含むメッキ液を用いて、副生成物であるリンの生成を抑制しメッキ被膜中に吸着するリン含有量を減らす方法（後期反応銅塩添加法）等が挙げられる。これらの方法は単独で用いてもよく、２種類以上を組み合わせて用いてもよい。   The method for producing conductive fine particles in which the phosphorus content in the thickness direction in the alloy plating film is smaller on the surface of the alloy plating film than on the core material particle side is not particularly limited. For example, electroless nickel plating In this method, the pH is gradually increased to increase the speed of the nickel plating reaction (pH raising method); the plating temperature is sequentially increased; the concentration of the reducing agent in the plating solution is successively increased; electroless nickel plating In the initial reaction, a plating solution containing a nickel salt and a phosphorus reducing agent is used, and in the latter reaction, a nickel salt added with a copper salt and a plating solution containing a phosphorus reducing agent are used, and by-product phosphorus is added. Examples include a method of suppressing the generation and reducing the phosphorus content adsorbed in the plating film (late reaction copper salt addition method). These methods may be used alone or in combination of two or more.

本発明の導電性微粒子を製造する方法としては、なかでも、上記ｐＨ上昇法と、上記後期反応銅塩添加法とを組み合わせて用いることが好ましい。これにより、合金メッキ被膜中の厚さ方向のリン含有量が、芯材粒子側よりも合金メッキ被膜表面側で少ない導電性微粒子を得ることができる。   As a method for producing the conductive fine particles of the present invention, it is particularly preferable to use a combination of the pH raising method and the late reaction copper salt addition method. Thereby, it is possible to obtain conductive fine particles in which the phosphorus content in the thickness direction in the alloy plating film is smaller on the surface of the alloy plating film than on the core material particle side.

本発明の導電性微粒子は、合金メッキ被膜中の厚さ方向において、芯材粒子側から２０％以下の領域でニッケル、及びリンを含有し、合金メッキ被膜表面側から８０％以下の領域でニッケル、銅、及びリンを含有することが好ましい。
合金メッキ被膜中の厚さ方向において、芯材粒子側から２０％以下の領域でニッケル、及びリンを含有し、合金メッキ被膜表面側から８０％以下の領域でニッケル、銅、及びリンを含有することにより、合金メッキ被膜と芯材粒子との密着性が良好で、合金メッキ被膜表面側から８０％以下の領域での銅の存在により合金メッキ被膜の導電性が良好な導電性微粒子となる。 The conductive fine particles of the present invention contain nickel and phosphorus in a region of 20% or less from the core particle side in the thickness direction in the alloy plating film, and nickel in a region of 80% or less from the surface of the alloy plating film. It is preferable to contain copper, and phosphorus.
In the thickness direction of the alloy plating film, nickel and phosphorus are contained in a region of 20% or less from the core particle side, and nickel, copper, and phosphorus are contained in a region of 80% or less from the alloy plating film surface side. As a result, the adhesion between the alloy plating film and the core particles is good, and the presence of copper in the region of 80% or less from the surface of the alloy plating film results in conductive fine particles with good conductivity of the alloy plating film.

以下、本発明の導電性微粒子における好ましい一態様について図面を参照して説明する。図１に示すように、本発明の導電性微粒子１は、芯材粒子２の表面に無電解メッキ法により合金メッキ被膜３を設けたものであり、合金メッキ被膜３中の厚さ方向において、芯材粒子２側から２０％以下の領域ａで、ニッケル、及びリンを含有し、合金メッキ被膜表面４側から８０％以下の領域ｂで、ニッケル、銅、及びリンを含有するものである。また、領域ａでのリン含有量よりも領域ｂでのリン含有量が少ないものがより好ましい。   Hereinafter, a preferred embodiment of the conductive fine particles of the present invention will be described with reference to the drawings. As shown in FIG. 1, the conductive fine particles 1 of the present invention are obtained by providing an alloy plating film 3 on the surface of the core material particle 2 by an electroless plating method, and in the thickness direction in the alloy plating film 3, The region a of 20% or less from the core particle 2 side contains nickel and phosphorus, and the region b of 80% or less from the alloy plating film surface 4 side contains nickel, copper and phosphorus. Moreover, the thing with less phosphorus content in the area | region b than the phosphorus content in the area | region a is more preferable.

上記導電性微粒子は、例えば、上記後期反応銅塩添加法を用いて、初期反応から後期反応に移行する時期を調整することにより得ることができる。
後期反応銅塩添加法を用いたときには、初期反応において、例えば、合金メッキ液中のｐＨを制御し反応速度を遅くすると、金属の沈着速度が遅く、副生成物であるリンの生成が早いため、リンが合金メッキ被膜中に多く取り込まれてリン含有量の多い合金メッキ被膜が形成される。このような合金メッキ被膜が形成された粒子は、リン含有量が多いため合金メッキ被膜を非磁性にすることで粒子の凝集性が少ないものとなるだけでなく、凹凸無く均一で緻密な合金メッキ被膜ができるため、芯材粒子との密着性に優れるものとなる。
また、凝集性は特に初期反応において起こり易いため、初期反応で合金メッキ被膜中のリン含有量を多くすると、凝集性は少ないものとすることができる。 The conductive fine particles can be obtained, for example, by adjusting the timing of transition from the initial reaction to the late reaction using the late reaction copper salt addition method.
When the late reaction copper salt addition method is used, in the initial reaction, for example, if the reaction rate is slowed by controlling the pH in the alloy plating solution, the metal deposition rate is slow, and the by-product phosphorus is generated quickly. A large amount of phosphorus is taken into the alloy plating film to form an alloy plating film having a high phosphorus content. Particles with such an alloy plating film have a high phosphorus content, so making the alloy plating film non-magnetic will not only reduce the cohesiveness of the particles, but also provide a uniform and dense alloy plating without unevenness. Since a film can be formed, the adhesiveness with the core particles is excellent.
In addition, since the agglomeration tends to occur particularly in the initial reaction, the agglomeration can be reduced by increasing the phosphorus content in the alloy plating film in the initial reaction.

本発明の導電性微粒子は、合金メッキ被膜中の厚さ方向において、芯材粒子側から２０％以下の領域で合金メッキ組成中に８〜１５重量％のリンを含有し、合金メッキ被膜表面側から８０％以下の領域で合金メッキ組成中に０．０５〜５重量％のリンを含有することが好ましい。
合金メッキ被膜中の厚さ方向において、芯材粒子側から２０％以下の領域で合金メッキ組成中に８〜１５重量％のリン含有量であると、凝集性が少なく芯材粒子との密着性が高いものとなる。また、合金メッキ被膜表面側から８０％以下の領域で合金メッキ組成中に０．０５〜５重量％のリン含有量であると、合金メッキ被膜の導電性が優れたものとなる。 The conductive fine particles of the present invention contain 8 to 15% by weight of phosphorus in the alloy plating composition in a region of 20% or less from the core particle side in the thickness direction in the alloy plating film, It is preferable that 0.05 to 5% by weight of phosphorus is contained in the alloy plating composition in an area of 80% to 80%.
When the phosphorus content is 8 to 15 wt% in the alloy plating composition in the region of 20% or less from the core particle side in the thickness direction in the alloy plating film, the cohesiveness is small and the adhesion to the core particle is small. Is expensive. Further, when the phosphorus content is 0.05 to 5% by weight in the alloy plating composition in the region of 80% or less from the surface side of the alloy plating film, the conductivity of the alloy plating film is excellent.

また、本発明の導電性微粒子は、合金メッキ被膜中の厚さ方向において、合金メッキ被膜表面側から８０％以下の領域で合金メッキ組成中に０．５〜９０重量％の銅を含有することが好ましい。
合金メッキ被膜中の厚さ方向において、合金メッキ被膜表面側から８０％以下の領域で合金メッキ組成中に０．５〜９０重量％の銅含有量であると、合金メッキ被膜の導電性が優れたものとなる。 Further, the conductive fine particles of the present invention contain 0.5 to 90% by weight of copper in the alloy plating composition in the region of 80% or less from the surface of the alloy plating film in the thickness direction in the alloy plating film. Is preferred.
When the copper content is 0.5 to 90% by weight in the alloy plating composition in the region of 80% or less from the surface of the alloy plating film in the thickness direction in the alloy plating film, the conductivity of the alloy plating film is excellent. It will be.

更に、本発明の導電性微粒子は、合金メッキ被膜中の厚さ方向において、芯材粒子側から２０％以下の領域で合金メッキ組成中に８５〜９２重量％のニッケルを含有し、合金メッキ被膜表面側から８０％以下の領域で合金メッキ組成中に５〜９９．４５重量％のニッケルを含有することが好ましい。   Furthermore, the conductive fine particles of the present invention contain 85 to 92% by weight of nickel in the alloy plating composition in the region of 20% or less from the core particle side in the thickness direction in the alloy plating film. It is preferable to contain 5 to 99.45% by weight of nickel in the alloy plating composition in an area of 80% or less from the surface side.

本発明における合金メッキ被膜中の各金属やリン等の含有比率は、例えば、ＥＤＸ（Ｅｎｅｒｇｙ Ｄｉｓｐｅｒｓｉｎｇ Ｘ−ｒａｙ ａｎａｌｙｚｅｒ：エネルギー分散型Ｘ線分析装置）により求めることができる。   The content ratio of each metal, phosphorus, etc. in the alloy plating film in the present invention can be determined by, for example, EDX (Energy Dispersing X-ray analyzer).

次に、本発明の導電性微粒子における好ましい他の態様について図面を参照して説明する。図２に示すように、本発明の導電性微粒子１１は、芯材粒子１２の表面に無電解メッキ法により合金メッキ被膜１３を設けたものであり、合金メッキ被膜１３中の厚さ方向において、芯材粒子１２側から２０％以下の領域Ａで、ニッケル、及びリンを含有し、合金メッキ被膜表面１４側から２０％以下の領域Ｃ、及び領域Ａと領域Ｃに挟まれた領域Ｂで、ニッケル、銅、及びリンを含有するものである。また、領域Ａでのリン含有量よりも領域Ｂでのリン含有量が少なく、領域Ｂでのリン含有量よりも領域Ｃでのリン含有量が少ないものがより好ましい。   Next, another preferred embodiment of the conductive fine particles of the present invention will be described with reference to the drawings. As shown in FIG. 2, the conductive fine particles 11 of the present invention are obtained by providing an alloy plating film 13 on the surface of the core material particles 12 by an electroless plating method, and in the thickness direction in the alloy plating film 13, In the region A of 20% or less from the core particle 12 side, containing nickel and phosphorus, in the region C of 20% or less from the alloy plating film surface 14 side, and in the region B sandwiched between the region A and the region C, It contains nickel, copper, and phosphorus. Moreover, the phosphorus content in the region B is smaller than the phosphorus content in the region A, and the phosphorus content in the region C is less than the phosphorus content in the region B.

本発明の導電性微粒子は、上記ＥＤＸで求めた、合金メッキ被膜中に含有されるリン（Ｐ）又は銅（Ｃｕ）と、ニッケル（Ｎｉ）との原子数の比Ｐ／Ｎｉ、Ｃｕ／Ｎｉが、図２における領域Ａで０．０５＜Ｐ／Ｎｉ＜０．５、領域Ｂで０．０５＜Ｐ／Ｎｉ＜０．５及び０＜Ｃｕ／Ｎｉ＜０．０５、領域Ｃで０．０３＜Ｐ／Ｎｉ＜０．５及び０．０５＜Ｃｕ／Ｎｉ＜８とすることが好ましい。更に、領域Ｂでは領域ＡよりもＰ／Ｎｉを小さくし、領域Ｃでは領域ＢよりもＰ／Ｎｉを小さく、Ｃｕ／Ｎｉを大きくすることがより好ましい。   The conductive fine particles of the present invention are obtained by the above EDX, and the ratio of the number of atoms P / Ni, Cu / Ni between phosphorus (P) or copper (Cu) and nickel (Ni) contained in the alloy plating film 2 is 0.05 <P / Ni <0.5 in the region A in FIG. 2, 0.05 <P / Ni <0.5 and 0 <Cu / Ni <0.05 in the region B, and 0. It is preferable that 03 <P / Ni <0.5 and 0.05 <Cu / Ni <8. Further, it is more preferable that P / Ni is smaller in region B than region A, P / Ni is smaller than region B, and Cu / Ni is larger in region C.

これにより、本発明の導電性微粒子の、表面のリンの含有量を低下させ導電性を高める効果だけではなく、銅を含有するメッキによることから通常のニッケル−リン被膜よりも格段に導電性を高め、更に、導電性微粒子の凝集性の抑制及び芯材粒子との密着性を向上させることができる。   As a result, the conductive fine particles of the present invention not only have the effect of reducing the phosphorus content on the surface and increasing the conductivity, but also the conductivity significantly higher than that of a normal nickel-phosphorus coating because of the plating containing copper. Furthermore, the cohesiveness of the conductive fine particles can be suppressed and the adhesion with the core material particles can be improved.

本発明の導電性微粒子は、更に、合金メッキ被膜の表面に金被膜が形成されていることが好ましい。
金被膜の形成方法としては、例えば、置換金メッキ法や還元金メッキ法等の無電解金メッキ法、電解金メッキ法、スパッタリング法等が挙げられる。なかでも、無電解金メッキ法が好ましい。
無電解金メッキとして、例えば、上記置換金メッキが施される場合、合金メッキ被膜の、例えばニッケルの純度が高いほど置換反応が容易に進むが、本発明の導電性微粒子では、合金メッキ被膜表面側のリン含有量が非常に低いため、緻密な金被膜を形成することができる。 The conductive fine particles of the present invention preferably further have a gold film formed on the surface of the alloy plating film.
Examples of the method for forming the gold film include electroless gold plating methods such as a displacement gold plating method and a reduction gold plating method, an electrolytic gold plating method, and a sputtering method. Of these, the electroless gold plating method is preferable.
As the electroless gold plating, for example, when the substitution gold plating is performed, the substitution reaction proceeds more easily as the purity of the nickel plating film, for example, the nickel, is increased. Since the phosphorus content is very low, a dense gold film can be formed.

本発明の導電性微粒子を得るための製造方法は、上記後期反応銅塩添加法が好ましいが、具体的には、金属触媒を担持させた芯材粒子の水性懸濁液に、ニッケル塩、リン系還元剤、及びｐＨ調整剤を含むメッキ液を添加して初期無電解メッキ反応を行い、その後、ニッケル塩、銅塩、リン系還元剤、及びｐＨ調整剤を含むメッキ液を添加して後期無電解メッキ反応を行う方法であることが好ましい。
金属触媒を担持させた芯材粒子の水性懸濁液に、ニッケル塩、リン系還元剤、及びｐＨ調整剤を含むメッキ液を添加して初期無電解メッキ反応を行い、その後、ニッケル塩、銅塩、リン系還元剤、及びｐＨ調整剤を含むメッキ液を添加して後期無電解メッキ反応を行う本発明の導電性微粒子の製造方法もまた、本発明の一つである。 The production method for obtaining the conductive fine particles of the present invention is preferably the above-mentioned late reaction copper salt addition method. Specifically, a nickel salt, phosphorous is added to an aqueous suspension of core material particles carrying a metal catalyst. An initial electroless plating reaction is performed by adding a plating solution containing a system reducing agent and a pH adjusting agent, and then a plating solution containing a nickel salt, a copper salt, a phosphorus reducing agent, and a pH adjusting agent is added. A method of performing an electroless plating reaction is preferable.
An initial electroless plating reaction is performed by adding a plating solution containing a nickel salt, a phosphorus-based reducing agent, and a pH adjuster to an aqueous suspension of core material particles supporting a metal catalyst, and then nickel salt, copper The method for producing conductive fine particles of the present invention in which a plating solution containing a salt, a phosphorus-based reducing agent, and a pH adjusting agent is added to perform a late electroless plating reaction is also one aspect of the present invention.

以下、更に、本発明の、導電性微粒子の製造方法について説明する。
本発明の、導電性微粒子の製造方法は、初期反応において、金属触媒を担持させた芯材粒子の水性懸濁液に、ニッケル塩、リン系還元剤、及びｐＨ調整剤を含むメッキ液を添加することにより、メッキ浴の安定性が高いものとなる。 Hereinafter, the manufacturing method of the electroconductive fine particles of this invention is demonstrated.
In the method for producing conductive fine particles of the present invention, in the initial reaction, a plating solution containing a nickel salt, a phosphorus reducing agent, and a pH adjusting agent is added to an aqueous suspension of core material particles supporting a metal catalyst. By doing so, the stability of the plating bath becomes high.

本発明の、導電性微粒子の具体的な製造方法としては、例えば、芯材粒子表面に、パラジウム等の貴金属触媒を担持させ、このパラジウムを担持させた芯材粒子を水溶性液中に投入し、水性懸濁液とし、ニッケル塩、リン系還元剤、及びｐＨ調整剤を含むメッキ液を滴下させ、初期反応を完結させた後、ニッケル塩、銅塩、リン系還元剤、及びｐＨ調整剤を含むメッキ液を滴下させ、後期反応を完結させる。これにより、無電解メッキされた導電性微粒子を得ることができる。   As a specific method for producing the conductive fine particles of the present invention, for example, a noble metal catalyst such as palladium is supported on the surface of the core material particles, and the core material particles supporting the palladium are put into an aqueous solution. Then, after making an aqueous suspension and dropping a plating solution containing a nickel salt, a phosphorus reducing agent, and a pH adjusting agent to complete the initial reaction, a nickel salt, a copper salt, a phosphorus reducing agent, and a pH adjusting agent A plating solution containing is dropped to complete the late reaction. Thereby, electroless-plated electroconductive fine particles can be obtained.

上記の製造方法において、パラジウム等の貴金属触媒を担持させた芯材粒子を得るためには、表面にパラジウムイオン等の貴金属イオンをキレート又は塩として捕捉できる芯材粒子、即ち、貴金属イオンの捕捉能を有する芯材粒子を用意し、それに貴金属イオンを捕捉させ、次いで還元剤を適用することにより、芯材粒子の表面に貴金属触媒を担持させることが好ましい。   In the production method described above, in order to obtain core material particles carrying a noble metal catalyst such as palladium, core material particles capable of capturing noble metal ions such as palladium ions as chelates or salts on the surface, that is, noble metal ion capturing ability It is preferable to support the noble metal catalyst on the surface of the core material particles by preparing the core material particles having the following, capturing noble metal ions therein, and then applying a reducing agent.

表面にパラジウムイオン等の貴金属イオンをキレート又は塩として捕捉できる芯材粒子としては、表面にアミノ基又はイミノ基等の官能基を有する芯材粒子が好ましく、特にアミノ基の官能基を有する芯材粒子がより好ましい。   As core material particles capable of capturing noble metal ions such as palladium ions as chelates or salts on the surface, core material particles having functional groups such as amino groups or imino groups on the surface are preferable, and core materials having amino group functional groups in particular. Particles are more preferred.

また、上記官能基を有さない芯材粒子であっても、例えば、カチオン系の界面活性剤にて表面処理を行うことによって、表面にパラジウムイオン等の貴金属イオンを捕捉できる芯材粒子を得ることができる。   Moreover, even if it is a core particle which does not have the said functional group, the core particle which can capture noble metal ions, such as palladium ion, on the surface is obtained by performing a surface treatment with a cationic surfactant, for example. be able to.

表面に貴金属触媒を担持させた芯材粒子としては、通常の分散手法により水中に懸濁させることができるものであればその形状は特に限定されるものではなく、例えば、球状、繊維状、中空状、針状等の特定の形状を持った粒子でもよく、不定形状の粒子であってもよい。なかでも、良好な電気的接続を得るために芯材粒子は球状が好ましい。   The shape of the core particle having the noble metal catalyst supported on the surface is not particularly limited as long as it can be suspended in water by a normal dispersion method. For example, the shape is spherical, fibrous, hollow It may be a particle having a specific shape such as a shape or a needle shape, or may be a particle having an indefinite shape. Of these, the core particles are preferably spherical in order to obtain good electrical connection.

上記芯材粒子の粒径は、特に限定されるものではないが、１〜１００μｍが好ましく、２〜２０μｍがより好ましい。   The particle diameter of the core material particles is not particularly limited, but is preferably 1 to 100 μm, and more preferably 2 to 20 μm.

上記芯材粒子の材質は、適度な弾性率、弾性変形性及び復元性を有するものであれば、有機系材料であっても無機系材料であってもよく特に限定されないが、樹脂粒子等の有機系材料であることが好ましい。
上記有機系材料としては、特に限定されず、例えば、フェノール樹脂、アミノ樹脂、ポリエステル樹脂、尿素樹脂、メラミン樹脂、エポキシ樹脂、ジビニルベンゼン重合体；ジビニルベンゼン−スチレン共重合体、ジビニルベンゼン−（メタ）アクリル酸エステル共重合体等のジビニルベンゼン系重合体；（メタ）アクリル酸エステル重合体等が挙げられる。上記（メタ）アクリル酸エステル重合体は、必要に応じて架橋型、非架橋型いずれを用いてもよく、これらを混合して用いてもよい。なかでも、ジビニルベンゼン系重合体、（メタ）アクリル酸エステル系重合体が好ましく用いられる。ここで、（メタ）アクリル酸エステルとはメタクリル酸エステル又はアクリル酸エステルを意味する。
上記無機系材料としては、例えば、金属、ガラス、セラミックス、金属酸化物、金属ケイ酸塩、金属炭化物、金属窒化物、金属炭酸塩、金属硫酸塩、金属リン酸塩、金属硫化物、金属酸塩、金属ハロゲン化物、炭素等が挙げられる。
これらの芯材粒子は、単独で用いられてもよく、２種類以上が併用されてもよい。 The material of the core material particles is not particularly limited as long as it has an appropriate elastic modulus, elastic deformability, and resilience, and may be an organic material or an inorganic material. An organic material is preferable.
The organic material is not particularly limited, and for example, phenol resin, amino resin, polyester resin, urea resin, melamine resin, epoxy resin, divinylbenzene polymer; divinylbenzene-styrene copolymer, divinylbenzene- (meta ) Divinylbenzene polymers such as acrylic acid ester copolymers; (meth) acrylic acid ester polymers. The (meth) acrylic acid ester polymer may be used in a cross-linked type or a non-cross-linked type, if necessary, and may be used in combination. Of these, divinylbenzene polymers and (meth) acrylic acid ester polymers are preferably used. Here, (meth) acrylic acid ester means methacrylic acid ester or acrylic acid ester.
Examples of the inorganic material include metal, glass, ceramics, metal oxide, metal silicate, metal carbide, metal nitride, metal carbonate, metal sulfate, metal phosphate, metal sulfide, and metal acid. Examples thereof include salts, metal halides, and carbon.
These core particle | grains may be used independently and 2 or more types may be used together.

上記芯材粒子に貴金属イオンを捕捉させる方法としては、例えば、芯材粒子を貴金属塩の希薄な酸性水溶液に分散させ、芯材粒子に貴金属イオンを捕捉させる方法等が挙げられる。
上記方法において、酸性水溶液中の貴金属塩として塩化パラジウムを使用する場合は、濃度を０．００１〜０．８重量％とすることが好ましく、硫酸パラジウムを使用する場合は、０．００５〜０．２重量％とすることが好ましい。 Examples of the method for capturing the noble metal ions by the core material particles include a method of dispersing the core material particles in a dilute acidic aqueous solution of a noble metal salt and capturing the noble metal ions by the core material particles.
In the above method, when palladium chloride is used as the noble metal salt in the acidic aqueous solution, the concentration is preferably 0.001 to 0.8% by weight, and when palladium sulfate is used, 0.005 to 0.00%. It is preferable to set it as 2 weight%.

また、芯材粒子に捕捉させた貴金属イオンを貴金属触媒とするためには、貴金属イオンを捕捉させた後の酸性水溶液に、例えばニッケルメッキに使用するリン系又はホウ素系還元剤を使用し、貴金属イオンを還元させて貴金属触媒とすることが好ましい。   Further, in order to use the noble metal ions trapped in the core particles as a noble metal catalyst, a phosphorous or boron reducing agent used for nickel plating, for example, is used in the acidic aqueous solution after the noble metal ions are trapped. It is preferable to reduce ions to form a noble metal catalyst.

本発明の、導電性微粒子の製造方法においては、貴金属触媒を担持させた芯材粒子の水性懸濁液を調製する際、水性懸濁液で凝集が起きないように、水性懸濁液中の芯材粒子の濃度は、０．５〜１．５重量％とすることが好ましい。   In the method for producing conductive fine particles of the present invention, when preparing an aqueous suspension of core material particles supporting a noble metal catalyst, the aqueous suspension is prepared so that aggregation does not occur in the aqueous suspension. The concentration of the core material particles is preferably 0.5 to 1.5% by weight.

更に、上記水性懸濁液には、メッキ反応開始時の反応液のｐＨを調整するため、例えば、アンモニア、水酸化ナトリウム、硫酸、塩酸等を添加することが好ましい。   Furthermore, for example, ammonia, sodium hydroxide, sulfuric acid, hydrochloric acid or the like is preferably added to the aqueous suspension in order to adjust the pH of the reaction solution at the start of the plating reaction.

本発明の、導電性微粒子の製造方法におけるリン系還元剤としては、例えば、次亜リン酸ナトリウム、次亜リン酸カルシウム、次亜リン酸等が挙げられる。
上記リン系還元剤の濃度は、３〜３０重量％とすることが好ましい。 Examples of the phosphorus reducing agent in the method for producing conductive fine particles of the present invention include sodium hypophosphite, calcium hypophosphite, hypophosphorous acid and the like.
The concentration of the phosphorus reducing agent is preferably 3 to 30% by weight.

本発明の、導電性微粒子の製造方法においては、メッキ液に錯化剤を含むことが好ましい。
上記錯化剤としては、金属イオンに対して錯化作用を有する化合物であれば特に限定されず、例えば、リンゴ酸、乳酸、酒石酸、クエン酸、グルコン酸、ヒドロキシ酢酸等のカルボン酸又はそのアルカリ金属塩；アンモニウム塩等のカルボン酸塩；グリシン等のアミノ酸；エチレンジアミン、アルキルアミン等のアミン類；アンモニウム、ＥＤＴＡ、ピロリン酸塩等が挙げられる。
上記錯化剤の濃度は、０．１〜８重量％とすることが好ましい。 In the method for producing conductive fine particles of the present invention, it is preferable that the plating solution contains a complexing agent.
The complexing agent is not particularly limited as long as it is a compound having a complexing action on metal ions. For example, carboxylic acids such as malic acid, lactic acid, tartaric acid, citric acid, gluconic acid, hydroxyacetic acid, or alkalis thereof. Examples thereof include metal salts; carboxylates such as ammonium salts; amino acids such as glycine; amines such as ethylenediamine and alkylamine; ammonium, EDTA, pyrophosphate and the like.
The concentration of the complexing agent is preferably 0.1 to 8% by weight.

本発明の、導電性微粒子の製造方法においては、初期反応に用いるメッキ液と、後期反応に用いるメッキ液とを調製する。
上記初期反応、即ち、リン含有量の多い芯材粒子側のメッキ被膜の形成においては、メッキ液は、例えば、硫酸ニッケルや塩化ニッケル等のニッケル塩水溶液、次亜リン酸ナトリウム等のリン系還元剤、ｐＨ調整剤、及び錯化剤等を含有させた一液にするのが好ましい。 In the method for producing conductive fine particles of the present invention, a plating solution used for the initial reaction and a plating solution used for the late reaction are prepared.
In the initial reaction, that is, the formation of the plating film on the core particle side having a high phosphorus content, the plating solution is, for example, a nickel salt aqueous solution such as nickel sulfate or nickel chloride, or a phosphorus-based reduction such as sodium hypophosphite. It is preferable to use a single solution containing an agent, a pH adjuster, a complexing agent and the like.

上記後期反応においては、メッキ液は、例えば、硫酸ニッケルや塩化ニッケル等のニッケル塩水溶液、硫酸銅や塩化銅等の銅塩水溶液、錯化剤、及び安定剤を含有させた液１と、次亜リン酸ナトリウム等のリン系還元剤、及びｐＨ調整剤を含有させた液２との二液に調製することが好ましい。
上記液１と上記液２とは、後期反応で使用前に混合して後期反応用メッキ液として用いられることが好ましい。 In the latter reaction, the plating solution includes, for example, a solution 1 containing a nickel salt aqueous solution such as nickel sulfate or nickel chloride, a copper salt aqueous solution such as copper sulfate or copper chloride, a complexing agent, and a stabilizer. It is preferable to prepare two liquids with a liquid 2 containing a phosphorus-based reducing agent such as sodium phosphite and a pH adjuster.
The liquid 1 and the liquid 2 are preferably mixed in a late reaction before use and used as a late reaction plating solution.

上記後期反応において、後期反応用メッキ液中のニッケル塩の濃度は、メッキ被膜の膜厚に応じて定められるが、例えば、比表面積が１．３ｍ2 ／ｇ、粒径４μｍの芯材粒子に膜厚０．０１〜０．０５μｍのメッキ被膜を形成する場合は、５〜２５重量％とすることが好ましい。また、銅塩の濃度としては、添加したニッケル塩の濃度の１／２から５倍にすることが好ましい。
更に、後期反応用メッキ液中の還元剤の濃度は、３〜３０重量％とすることが好ましい。 In the late reaction, the concentration of nickel salt in the late reaction plating solution is determined according to the film thickness of the plating film. For example, the core surface particles having a specific surface area of 1.3 m 2 / g and a particle diameter of 4 μm are used. In the case of forming a plating film having a thickness of 0.01 to 0.05 μm, the content is preferably 5 to 25% by weight. The concentration of the copper salt is preferably 1/2 to 5 times the concentration of the added nickel salt.
Furthermore, the concentration of the reducing agent in the late reaction plating solution is preferably 3 to 30% by weight.

本発明においては、上記初期反応から上記後期反応に移行する時期を調整することにより、合金メッキ被膜中の厚さ方向において、芯材粒子側から２０％以下の領域でニッケル、及びリンを含有し、合金メッキ被膜表面側から８０％以下の領域でニッケル、銅、及びリンを含有する導電性微粒子とすることができる。   In the present invention, by adjusting the timing of transition from the initial reaction to the late reaction, it contains nickel and phosphorus in a region of 20% or less from the core particle side in the thickness direction in the alloy plating film. The conductive fine particles containing nickel, copper, and phosphorus can be formed in an area of 80% or less from the surface of the alloy plating film.

後期反応において、合金メッキ被膜中の厚さ方向において、合金メッキ被膜表面側から８０％以下の領域で、リン含有量が合金メッキ被膜表面側で少ないものを製造する方法としては、例えば、無電解メッキにおいて、ｐＨを順次高くし、ニッケルメッキ反応の速度を速めていく方法；メッキ温度を順次高くする方法；メッキ液中の還元剤の濃度を順次高くする方法等が挙げられる。これらの方法は単独で用いてもよく、２種類以上を組み合わせて用いてもよい。なかでも、ｐＨを順次高くする方法によりリン含有量を少なくすることが好ましい。このようにリン含有量が合金メッキ被膜表面側で少ないものとすると、銅含有量は合金メッキ被膜表面側で多いものとすることができる。   In a late reaction, in the thickness direction in the alloy plating film, a method for producing a material having a low phosphorus content on the alloy plating film surface side in a region of 80% or less from the alloy plating film surface side is, for example, electroless In plating, there are a method of increasing the pH sequentially and increasing the speed of the nickel plating reaction; a method of increasing the plating temperature sequentially; a method of increasing the concentration of the reducing agent in the plating solution sequentially. These methods may be used alone or in combination of two or more. Among these, it is preferable to reduce the phosphorus content by a method of sequentially increasing the pH. As described above, when the phosphorus content is small on the alloy plating film surface side, the copper content can be large on the alloy plating film surface side.

また、後期反応において、粒子の凝集の抑制及びメッキ浴の安定性を得るためには、極力メッキ温度を下げることが好ましい。より具体的には、メッキ液が添加されたメッキ浴の温度を２０〜４０℃とすることが好ましい。
このためには、初期反応でメッキ温度を極力下げることが好ましく、これにより、後期反応で温度調節が容易になり作業性が向上し易い。 Further, in the late reaction, it is preferable to lower the plating temperature as much as possible in order to suppress the aggregation of particles and to stabilize the plating bath. More specifically, the temperature of the plating bath to which the plating solution is added is preferably 20 to 40 ° C.
For this purpose, it is preferable to lower the plating temperature as much as possible in the initial reaction, and this makes it easier to adjust the temperature in the later reaction and to improve workability.

なお、ニッケル及び銅を含有するリン濃度の低い合金メッキ被膜が表面に形成された場合は、メッキ中の粒子は急激に凝集しやすくなることがあるので、合金メッキ反応に伴う水素の発生が認められなくなった後、粒子の凝集が生じる前に合金メッキ反応を終了させることが好ましい。   In addition, when an alloy plating film containing nickel and copper and having a low phosphorus concentration is formed on the surface, particles during plating may easily agglomerate, so that hydrogen generation due to the alloy plating reaction is recognized. It is preferred that the alloy plating reaction be terminated after no longer being agglomerated and before particle agglomeration occurs.

合金メッキ反応の終了後は、攪拌を１０分から２０分程度続けて熟成させ、その後、粒子を濾過し、アルコール、温水等で洗浄し、乾燥することで、導電性微粒子を得ることができる。   After completion of the alloy plating reaction, conductive fine particles can be obtained by aging by continuing stirring for about 10 to 20 minutes, and then filtering the particles, washing with alcohol, warm water, etc., and drying.

本発明の異方性導電材料は、上述した本発明の導電性微粒子が樹脂バインダーに分散されてなるものである。   The anisotropic conductive material of the present invention is obtained by dispersing the above-described conductive fine particles of the present invention in a resin binder.

上記異方性導電材料としては、本発明の導電性微粒子が樹脂バインダーに分散されていれば特に限定されるものではなく、例えば、異方性導電ペースト、異方性導電インク、異方性導電粘接着剤、異方性導電フィルム、異方性導電シート等が挙げられる。   The anisotropic conductive material is not particularly limited as long as the conductive fine particles of the present invention are dispersed in a resin binder. For example, anisotropic conductive paste, anisotropic conductive ink, anisotropic conductive An adhesive, an anisotropic conductive film, an anisotropic conductive sheet, etc. are mentioned.

本発明の異方性導電材料の作製方法としては、特に限定されるものではないが、例えば、絶縁性の樹脂バインダー中に本発明の導電性微粒子を添加し、均一に混合して分散させ、例えば、異方性導電ペースト、異方性導電インク、異方性導電粘接着剤等とする方法や、絶縁性の樹脂バインダー中に本発明の導電性微粒子を添加し、均一に混合して導電性組成物を作製した後、この導電性組成物を必要に応じて有機溶媒中に均一に溶解（分散）させるか、又は加熱溶融させて、離型紙や離型フィルム等の離型材の離型処理面に所定のフィルム厚さとなるように塗工し、必要に応じて乾燥や冷却等を行って、例えば、異方性導電フィルム、異方性導電シート等とする方法等が挙げられ、作製しようとする異方性導電材料の種類に対応して、適宜の作製方法をとればよい。また、絶縁性の樹脂バインダーと、本発明の導電性微粒子とを、混合することなく、別々に用いて異方性導電材料としてもよい。   The method for producing the anisotropic conductive material of the present invention is not particularly limited. For example, the conductive fine particles of the present invention are added to an insulating resin binder, and mixed and dispersed uniformly. For example, a method of using an anisotropic conductive paste, anisotropic conductive ink, anisotropic conductive adhesive, etc., or adding the conductive fine particles of the present invention to an insulating resin binder and mixing them uniformly. After preparing the conductive composition, the conductive composition is uniformly dissolved (dispersed) in an organic solvent as necessary, or heated and melted to release a release material such as release paper or release film. Applying to the mold processing surface so as to have a predetermined film thickness, and performing drying or cooling as necessary, for example, an anisotropic conductive film, an anisotropic conductive sheet, etc. Depending on the type of anisotropic conductive material to be produced, Manufacturing methods may Taking. Further, the insulating resin binder and the conductive fine particles of the present invention may be used separately without being mixed to form an anisotropic conductive material.

上記絶縁性の樹脂バインダーの樹脂としては、特に限定されるものではないが、例えば、酢酸ビニル系樹脂、塩化ビニル系樹脂、アクリル系樹脂、スチレン系樹脂等のビニル系樹脂；ポリオレフィン系樹脂、エチレン−酢酸ビニル共重合体、ポリアミド系樹脂等の熱可塑性樹脂；エポキシ系樹脂、ウレタン系樹脂、ポリイミド系樹脂、不飽和ポリエステル系樹脂及びこれらの硬化剤からなる硬化性樹脂；スチレン−ブタジエン−スチレンブロック共重合体、スチレン−イソプレン−スチレンブロック共重合体、これらの水素添加物等の熱可塑性ブロック共重合体；スチレン−ブタジエン共重合ゴム、クロロプレンゴム、アクリロニトリル−スチレンブロック共重合ゴム等のエラストマー類（ゴム類）等が挙げられる。これらの樹脂は、単独で用いられてもよいし、２種以上が併用されてもよい。また、上記硬化性樹脂は、常温硬化型、熱硬化型、光硬化型、湿気硬化型等のいずれの硬化形態であってもよい。   The resin of the insulating resin binder is not particularly limited. For example, vinyl resins such as vinyl acetate resins, vinyl chloride resins, acrylic resins, styrene resins; polyolefin resins, ethylene -Thermoplastic resins such as vinyl acetate copolymers and polyamide resins; Epoxy resins, urethane resins, polyimide resins, unsaturated polyester resins, and curable resins composed of these curing agents; styrene-butadiene-styrene blocks Thermoplastic block copolymers such as copolymers, styrene-isoprene-styrene block copolymers, and hydrogenated products thereof; elastomers such as styrene-butadiene copolymer rubber, chloroprene rubber, acrylonitrile-styrene block copolymer rubber ( Rubbers). These resins may be used alone or in combination of two or more. The curable resin may be in any curing form such as a room temperature curing type, a thermosetting type, a photocuring type, and a moisture curing type.

本発明の異方性導電材料には、絶縁性の樹脂バインダー、及び、本発明の導電性微粒子に加えるに、本発明の課題達成を阻害しない範囲で必要に応じて、例えば、増量剤、軟化剤（可塑剤）、粘接着性向上剤、酸化防止剤（老化防止剤）、熱安定剤、光安定剤、紫外線吸収剤、着色剤、難燃剤、有機溶媒等の各種添加剤の１種又は２種以上が併用されてもよい。   In addition to the insulating resin binder and the conductive fine particles of the present invention, the anisotropic conductive material of the present invention includes, for example, a bulking agent, a softening agent, etc. 1 type of various additives such as additives (plasticizers), tackifiers, antioxidants (anti-aging agents), heat stabilizers, light stabilizers, UV absorbers, colorants, flame retardants, organic solvents, etc. Or 2 or more types may be used together.

（作用）
本発明の導電性微粒子は、例えば、合金メッキ液中のｐＨを制御し、初期反応においてはｐＨを低くすることにより反応速度が遅くなり、芯材粒子側では、金属の沈着速度が遅く、副生成物であるリンの生成が早いため、リンが合金メッキ被膜中に多く取り込まれてリン含有量の多い合金メッキ被膜が形成される。このような合金メッキ被膜が形成された粒子は、リン含有量が多いため合金メッキ被膜を非磁性にすることで粒子の凝集性が少ないものとなるだけでなく、凹凸無く均一で緻密な合金メッキ被膜ができるため、芯材粒子との密着性が高いものとなる。 (Function)
For example, the conductive fine particles of the present invention have a low reaction rate by controlling the pH in the alloy plating solution and lowering the pH in the initial reaction. On the core particle side, the metal deposition rate is slow, Since the product phosphorus is generated quickly, a large amount of phosphorus is incorporated into the alloy plating film to form an alloy plating film with a high phosphorus content. Particles with such an alloy plating film have a high phosphorus content, so making the alloy plating film non-magnetic will not only reduce the cohesiveness of the particles, but also provide a uniform and dense alloy plating without unevenness. Since a film is formed, the adhesiveness with the core material particles is high.

また、初期反応後、後期反応に移行したとき、後期反応では、銅塩を使用しているため、副生成物であるリンの生成を抑制し、代わりに銅が析出するため、リンが合金メッキ被膜中に析出することが少なくなる。更に、例えば合金メッキ液中のｐＨを順次高くすることによりリン含有量が合金メッキ被膜表面側で少なくなり銅含有量が合金メッキ被膜表面側でより多くなる。
従って、得られる導電性微粒子は、合金メッキ被膜に導電性のよい銅を含有しているため優れた導電性を有し、更に、合金メッキ被膜表面側は導電阻害物質であるリン含有量が少なく銅含有量が多いため優れた導電性を有するものになる。 In addition, when the transition to the late reaction occurs after the initial reaction, since the copper salt is used in the late reaction, the production of phosphorus, which is a by-product, is suppressed, and instead copper is precipitated, so phosphorus is alloy plated. Less precipitation in the coating. Further, for example, by sequentially increasing the pH in the alloy plating solution, the phosphorus content decreases on the alloy plating film surface side, and the copper content increases on the alloy plating film surface side.
Accordingly, the obtained conductive fine particles have excellent conductivity because the alloy plating film contains copper having good conductivity, and the surface of the alloy plating film has a low content of phosphorus, which is a conductivity-inhibiting substance. Since the copper content is large, it has excellent conductivity.

更に、合金メッキ被膜表面側におけるリン濃度が非常に低濃度であるため、金メッキを施したとき、金との置換反応を促進し、容易に緻密な置換金メッキを得ることができ、非常に優れた導電性微粒子になる。   Furthermore, since the phosphorus concentration on the surface of the alloy plating film is very low, when gold plating is applied, the substitution reaction with gold is promoted, and a dense replacement gold plating can be easily obtained, which is very excellent. It becomes conductive fine particles.

本発明における導電性微粒子は、芯材粒子とのメッキ密着性に優れるため、異方性導電材料とするために、樹脂バインダーと混錬分散しても、メッキ被膜が剥がれ落ち難い。また、合金メッキ被膜に導電性のよい銅を含有しているため、本発明の導電性微粒子を用いた本発明の異方性導電材料は、優れた導電性を有するものとなる。   Since the conductive fine particles in the present invention are excellent in plating adhesion with the core material particles, the plating film is hardly peeled off even if kneaded and dispersed with a resin binder in order to make an anisotropic conductive material. Moreover, since the alloy plating film contains copper having good conductivity, the anisotropic conductive material of the present invention using the conductive fine particles of the present invention has excellent conductivity.

本発明の導電性微粒子は、上述の構成よりなるので、優れた導電性を有し、更に、芯材粒子との密着性が高くかつ凝集性が少ないものを得ることが可能となった。また、本発明の導電性微粒子の製造方法は、メッキ浴の安定性が高く、優れた導電性を有し、芯材粒子との密着性が高くかつ凝集性が少ない製造方法を得ることが可能となった。更に、本発明の導電性微粒子を用いた異方性導電材料は、優れた導電性を有するものとなった。   Since the conductive fine particles of the present invention have the above-described configuration, it is possible to obtain those having excellent conductivity, and having high adhesion to the core material particles and low cohesion. In addition, the method for producing conductive fine particles of the present invention can provide a production method in which the stability of the plating bath is high, the conductivity is excellent, the adhesiveness with the core particles is high, and the cohesiveness is low. It became. Furthermore, the anisotropic conductive material using the conductive fine particles of the present invention has excellent conductivity.

以下、実施例を挙げて本発明をより詳しく説明する。なお、本発明は以下の実施例に限定されるものではない。   Hereinafter, the present invention will be described in more detail with reference to examples. In addition, this invention is not limited to a following example.

（実施例１）
粒径４μｍのジビニルベンゼン系重合体樹脂粒子（積水化学工業社製、「ＳＰ−２０４」）を、イオン吸着剤の１０重量％溶液で５分間処理し、その後、硫酸パラジウム０．０１重量％水溶液で５分間処理し、更にジメチルアミンボランを加えて還元処理を施し、濾過、洗浄することにより、パラジウムを担持させた芯材粒子を得た。 Example 1
Divinylbenzene polymer resin particles having a particle size of 4 μm (“SP-204” manufactured by Sekisui Chemical Co., Ltd.) are treated with a 10 wt% solution of an ion adsorbent for 5 minutes, and then a 0.01 wt% palladium sulfate aqueous solution. Then, dimethylamine borane was further added for reduction treatment, followed by filtration and washing to obtain palladium-supported core particles.

次に、コハク酸ナトリウム１重量％を含むイオン交換水５００ｍｌを調製し、得られた芯材粒子１０gを混合して水性懸濁液を調製し、更に硫酸を添加してｐＨ５の水性懸濁液に調製した。   Next, 500 ml of ion-exchanged water containing 1% by weight of sodium succinate is prepared, 10 g of the obtained core material particles are mixed to prepare an aqueous suspension, and sulfuric acid is further added to form an aqueous suspension with pH 5 Prepared.

一方、初期反応用合金メッキ液として、硫酸ニッケル２０重量％、次亜リン酸ナトリウム２０重量％、及び水酸化ナトリウム８重量％を含む合金メッキ液を調製した。   On the other hand, an alloy plating solution containing 20% by weight of nickel sulfate, 20% by weight of sodium hypophosphite, and 8% by weight of sodium hydroxide was prepared as an alloy plating solution for initial reaction.

得られた水性懸濁液を８０℃にし、これに得られた初期反応用合金メッキ液を連続的に滴下し、２０分間攪拌することにより初期無電解メッキ反応を行った。このメッキ反応中に、著しい凝集は無く、水素の発生がなくなることを確認して、初期反応を終了させた。   The obtained aqueous suspension was brought to 80 ° C., and the initial reaction alloy plating solution thus obtained was continuously added dropwise thereto and stirred for 20 minutes to carry out an initial electroless plating reaction. During the plating reaction, it was confirmed that there was no significant aggregation and generation of hydrogen disappeared, and the initial reaction was terminated.

次に、後期反応用合金メッキ液として、硫酸ニッケル１０重量％、硫酸銅１０重量％、次亜リン酸ナトリウム５重量％、及び水酸化ナトリウム５重量％を含む合金メッキ液を調製した。   Next, an alloy plating solution containing 10% by weight of nickel sulfate, 10% by weight of copper sulfate, 5% by weight of sodium hypophosphite, and 5% by weight of sodium hydroxide was prepared as an alloy plating solution for late reaction.

その後、初期反応終了後の溶液に、得られた後期反応用合金メッキ液を連続的に滴下し、１時間攪拌することにより後期無電解メッキ反応を行い、合金メッキ被膜が形成された導電性微粒子（導電性微粒子１）を得た。   Thereafter, the resulting late reaction alloy plating solution is continuously dropped into the solution after completion of the initial reaction, and stirred for 1 hour to carry out the late electroless plating reaction, and the conductive fine particles on which the alloy plating film is formed. (Conductive fine particles 1) were obtained.

得られた合金メッキ被膜が形成された導電性微粒子に、更に、置換金メッキを行い、合金メッキ被膜に金被膜が形成された導電性微粒子（導電性微粒子２）を得た。   The obtained conductive fine particles on which the alloy plating film was formed were further subjected to displacement gold plating to obtain conductive fine particles (conductive fine particles 2) on which the gold film was formed on the alloy plating film.

（導電性微粒子の評価）
得られた導電性微粒子１及び導電性微粒子２について、断面を収束イオンビームで切り出し、２０万倍の透過型電子顕微鏡で観察して、メッキ被膜の状態及び膜厚を調査した。これらの導電性微粒子は、均質で繊細な合金メッキ被膜が緻密に沈着していた。
また、導電性微粒子１及び導電性微粒子２について、以下の導電性微粒子の抵抗値測定方法により、導電性（抵抗値）を調査した。
更に、導電性微粒子２について、以下のＥＤＸによる成分測定方法により合金メッキ被膜中のニッケル、銅、及びリンの含有量を調査した。
これらの結果を表１に示した。 (Evaluation of conductive fine particles)
The obtained conductive fine particles 1 and conductive fine particles 2 were cut out with a focused ion beam and observed with a 200,000-fold transmission electron microscope to investigate the state and film thickness of the plating film. These conductive fine particles were densely deposited with a homogeneous and delicate alloy plating film.
Further, the conductivity (resistance value) of the conductive fine particles 1 and the conductive fine particles 2 was examined by the following method for measuring the resistance value of the conductive fine particles.
Furthermore, about the electroconductive fine particles 2, content of nickel, copper, and phosphorus in an alloy plating film was investigated with the component measuring method by the following EDX.
These results are shown in Table 1.

（導電性微粒子の抵抗値測定方法）
微小圧縮試験機（「ＤＵＨ−２００」、島津製作所社製）を、抵抗値が測定できるようにして用い、導電性微粒子を圧縮しながら抵抗を測定することにより、導電性微粒子の抵抗値を測定した。 (Measurement method of resistance value of conductive fine particles)
Using a micro compression tester (“DUH-200”, manufactured by Shimadzu Corporation) so that the resistance value can be measured, the resistance value of the conductive fine particles is measured by measuring the resistance while compressing the conductive fine particles. did.

（ＥＤＸによる成分測定方法）
ＥＤＸ（「エネルギー分散型Ｘ線分光機」、日本電子データム社製）を用い、導電性微粒子の断面を収束イオンビームにて切り出し、合金メッキ被膜中の各部位を成分分析することにより、ニッケル、銅、及びリンの検出値を測定した。得られた測定値から合金メッキ組成中のニッケル、銅、及びリンの含有量を算出した。 (Component measurement method by EDX)
By using EDX (“Energy Dispersive X-ray Spectrometer”, manufactured by JEOL Datum), the cross section of the conductive fine particles is cut out with a focused ion beam, and each component in the alloy plating film is analyzed for components, The detected values of copper and phosphorus were measured. The contents of nickel, copper and phosphorus in the alloy plating composition were calculated from the measured values obtained.

（実施例２）
実施例１において、後期反応用合金メッキ液として、硫酸ニッケル１０重量％、硫酸銅１０重量％、次亜リン酸ナトリウム５重量％、及び水酸化ナトリウム５重量％を含む合金メッキ液を使用せず、代わりに硫酸ニッケル５重量％、硫酸銅１５重量％、次亜リン酸ナトリウム５重量％、及び水酸化ナトリウム５重量％を含む合金メッキ液を用いたこと以外は同様にして導電性微粒子１及び導電性微粒子２を得た。
実施例１と同様にして、導電性微粒子の評価を行った。これらの結果を表１に示した。これらの導電性微粒子は、均質で繊細な合金メッキ被膜が緻密に沈着していた。 (Example 2)
In Example 1, an alloy plating solution containing 10% by weight of nickel sulfate, 10% by weight of copper sulfate, 5% by weight of sodium hypophosphite, and 5% by weight of sodium hydroxide was not used as the late-stage reaction alloy plating solution. In the same manner, except that an alloy plating solution containing 5% by weight of nickel sulfate, 15% by weight of copper sulfate, 5% by weight of sodium hypophosphite, and 5% by weight of sodium hydroxide was used. Conductive fine particles 2 were obtained.
In the same manner as in Example 1, the conductive fine particles were evaluated. These results are shown in Table 1. These conductive fine particles were densely deposited with a homogeneous and delicate alloy plating film.

（実施例３）
実施例１において、後期反応用合金メッキ液として、硫酸ニッケル１０重量％、硫酸銅１０重量％、次亜リン酸ナトリウム５重量％、及び水酸化ナトリウム５重量％を含む合金メッキ液を使用せず、代わりに硫酸ニッケル１５重量％、硫酸銅５重量％、次亜リン酸ナトリウム５重量％、及び水酸化ナトリウム５重量％を含む合金メッキ液を用いたこと以外は同様にして導電性微粒子１及び導電性微粒子２を得た。
実施例１と同様にして、導電性微粒子の評価を行った。これらの結果を表１に示した。これらの導電性微粒子は、均質で繊細な合金メッキ被膜が緻密に沈着していた。 (Example 3)
In Example 1, an alloy plating solution containing 10% by weight of nickel sulfate, 10% by weight of copper sulfate, 5% by weight of sodium hypophosphite, and 5% by weight of sodium hydroxide was not used as the late-stage reaction alloy plating solution. In the same manner, except that an alloy plating solution containing 15% by weight of nickel sulfate, 5% by weight of copper sulfate, 5% by weight of sodium hypophosphite, and 5% by weight of sodium hydroxide was used, Conductive fine particles 2 were obtained.
In the same manner as in Example 1, the conductive fine particles were evaluated. These results are shown in Table 1. These conductive fine particles were densely deposited with a homogeneous and delicate alloy plating film.

（比較例１）
実施例１において、後期反応用合金メッキ液として、硫酸ニッケル１０重量％、硫酸銅１０重量％、次亜リン酸ナトリウム５重量％、及び水酸化ナトリウム５重量％を含む合金メッキ液を使用せず、代わりに硫酸ニッケル２０重量％、次亜リン酸ナトリウム５重量％、及び水酸化ナトリウム５重量％を含む合金メッキ液を用いたこと以外は同様にして導電性微粒子１及び導電性微粒子２を得た。
実施例１と同様にして、導電性微粒子の評価を行った。これらの結果を表１に示した。これらの導電性微粒子は、均質で繊細な合金メッキ被膜が緻密に沈着していた。 (Comparative Example 1)
In Example 1, an alloy plating solution containing 10% by weight of nickel sulfate, 10% by weight of copper sulfate, 5% by weight of sodium hypophosphite, and 5% by weight of sodium hydroxide was not used as the late-stage reaction alloy plating solution. Instead, conductive fine particles 1 and conductive fine particles 2 were obtained in the same manner except that an alloy plating solution containing 20% by weight of nickel sulfate, 5% by weight of sodium hypophosphite, and 5% by weight of sodium hydroxide was used. It was.
In the same manner as in Example 1, the conductive fine particles were evaluated. These results are shown in Table 1. These conductive fine particles were densely deposited with a homogeneous and delicate alloy plating film.

Figure 0004728665
Figure 0004728665

表１より、実施例１、実施例２、及び実施例３の導電性微粒子は、合金メッキ被膜中の厚さ方向でリン含有量が異なり、芯材粒子側よりも合金メッキ被覆表面側で少なく、なおかつ、合金メッキ被覆表面側で銅を含有していることが確認された。また、比較例１の導電性微粒子は、銅を含有していないことが確認された。
合金メッキ被膜中に銅を含有している導電性微粒子は、抵抗値が低く優れた導電性を有することがわかる。 From Table 1, the conductive fine particles of Example 1, Example 2, and Example 3 differ in phosphorus content in the thickness direction in the alloy plating film, and are less on the surface of the alloy plating coating than on the core particle side. In addition, it was confirmed that copper was contained on the alloy plating coating surface side. Moreover, it was confirmed that the electroconductive fine particles of Comparative Example 1 do not contain copper.
It can be seen that the conductive fine particles containing copper in the alloy plating film have a low resistance value and excellent conductivity.

（実施例４）
樹脂バインダーの樹脂としてエポキシ樹脂（油化シェルエポキシ社製、「エピコート８２８」）１００重量部、トリスジメチルアミノエチルフェノール２重量部、及びトルエン１００重量部に、実施例１で得られた導電性微粒子２を添加し、遊星式攪拌機を用いて充分に混合した後、離型フィルム上に乾燥後の厚さが７μｍとなるように塗布し、トルエンを蒸発させて導電性微粒子を含有する接着フィルムを得た。なお、導電性微粒子の配合量は、フィルム中の含有量が５万個／ｃｍ2 とした。
その後、導電性微粒子を含有する接着フィルムを、導電性微粒子を含有させずに得た接着フィルムと常温で貼り合わせ厚さ１７μｍで２層構造の異方性導電フィルムを得た。 Example 4
The conductive fine particles obtained in Example 1 were added to 100 parts by weight of an epoxy resin (“Epicoat 828” manufactured by Yuka Shell Epoxy Co., Ltd.), 2 parts by weight of trisdimethylaminoethylphenol, and 100 parts by weight of toluene as a resin binder resin. 2 was added and mixed thoroughly using a planetary stirrer, and then applied onto a release film so that the thickness after drying was 7 μm, and toluene was evaporated to form an adhesive film containing conductive fine particles. Obtained. In addition, the compounding quantity of electroconductive fine particles made content in a film 50,000 piece / cm < 2 >.
Thereafter, an adhesive film containing conductive fine particles was bonded to an adhesive film obtained without containing conductive fine particles at room temperature to obtain a two-layer anisotropic conductive film having a thickness of 17 μm.

（実施例５）
実施例２で得られた導電性微粒子２を添加したこと以外は実施例４と同様にして異方性導電フィルムを得た。 (Example 5)
An anisotropic conductive film was obtained in the same manner as in Example 4 except that the conductive fine particles 2 obtained in Example 2 were added.

（実施例６）
実施例３で得られた導電性微粒子２を添加したこと以外は実施例４と同様にして異方性導電フィルムを得た。 (Example 6)
An anisotropic conductive film was obtained in the same manner as in Example 4 except that the conductive fine particles 2 obtained in Example 3 were added.

（比較例２）
比較例１で得られた導電性微粒子２を添加したこと以外は実施例４と同様にして異方性導電フィルムを得た。 (Comparative Example 2)
An anisotropic conductive film was obtained in the same manner as in Example 4 except that the conductive fine particles 2 obtained in Comparative Example 1 were added.

（異方性導電材料の導電性評価）
得られた異方性導電フィルムを５×５ｍｍの大きさに切断した。また、一方に抵抗測定用の引き回し線を持つ、幅２００μｍ、長さ１ｍｍ、高さ０．２μｍ、Ｌ／Ｓ２０μｍのアルミニウム電極が形成されたガラス基板を２枚用意した。異方性導電フィルムを一方のガラス基板のほぼ中央に貼り付けた後、他方のガラス基板を異方性導電フィルムが貼り付けられたガラス基板の電極パターンと重なるように位置あわせをして貼り合わせた。
２枚のガラス基板を、圧力１０Ｎ、温度１８０℃の条件で熱圧着した後、電極間の抵抗値を測定した。実施例４、実施例５、実施例６、及び比較例２で得られた異方性導電フィルムについてそれぞれ測定した。
また、作製した試験片に対してＰＣＴ試験（８０℃、９５％ＲＨの高温高湿環境下で１０００時間保持）を行った後、電極間の抵抗値を測定した。
評価結果を表２に示す。 (Evaluation of conductivity of anisotropic conductive materials)
The obtained anisotropic conductive film was cut into a size of 5 × 5 mm. In addition, two glass substrates having a lead wire for resistance measurement on which an aluminum electrode having a width of 200 μm, a length of 1 mm, a height of 0.2 μm, and an L / S of 20 μm was formed were prepared. After attaching the anisotropic conductive film to the center of one glass substrate, align the other glass substrate so that it overlaps the electrode pattern of the glass substrate to which the anisotropic conductive film is attached. It was.
Two glass substrates were thermocompression bonded under the conditions of a pressure of 10 N and a temperature of 180 ° C., and then the resistance value between the electrodes was measured. The anisotropic conductive films obtained in Example 4, Example 5, Example 6, and Comparative Example 2 were measured.
In addition, after the PCT test (held at 80 ° C. in a high-temperature and high-humidity environment of 95% RH for 1000 hours) was performed on the prepared test piece, the resistance value between the electrodes was measured.
The evaluation results are shown in Table 2.

Figure 0004728665
Figure 0004728665

表２より、実施例で得られた導電性微粒子を用いた異方性導電フィルムは、比較例で得られた導電性微粒子を用いた異方性導電フィルムに比べ、抵抗値が低く優れた導電性を有することがわかる。   From Table 2, the anisotropic conductive film using the conductive fine particles obtained in Examples has a low resistance value and excellent conductivity compared to the anisotropic conductive film using the conductive fine particles obtained in Comparative Examples. It turns out that it has sex.

本発明によれば、優れた導電性を有し、更に、芯材粒子との密着性が高くかつ凝集性が少ない導電性微粒子、メッキ浴の安定性が高い該導電性微粒子の製造方法、及び該導電性微粒子を用いた異方性導電材料を提供できる。   According to the present invention, there are provided conductive fine particles having excellent conductivity, and having high adhesion to core particles and low cohesiveness, a method for producing the conductive fine particles having high plating bath stability, and An anisotropic conductive material using the conductive fine particles can be provided.

本発明の導電性微粒子の一態様で、導電性微粒子における合金メッキ被膜中のリン含有量の、測定部位の説明図である。It is explanatory drawing of the measurement site | part of the phosphorus content in the alloy plating film in electroconductive fine particles with one aspect | mode of the electroconductive fine particles of this invention. 本発明の導電性微粒子の他の態様で、導電性微粒子における合金メッキ被膜中のリン含有量の、測定部位の説明図である。It is explanatory drawing of the measurement site | part of the phosphorus content in the alloy plating film in electroconductive fine particles in the other aspect of the electroconductive fine particles of this invention.

符号の説明Explanation of symbols

１、１１ 導電性微粒子
２、１２ 芯材粒子
３、１３ 合金メッキ被膜
４、１４ 合金メッキ被膜表面
ａ 合金メッキ被膜中の厚さ方向において、芯材粒子側から２０％以下の領域
ｂ 合金メッキ被膜中の厚さ方向において、合金メッキ被膜表面側から８０％以下の領域
Ａ 合金メッキ被膜中の厚さ方向において、芯材粒子側から２０％以下の領域
Ｃ 合金メッキ被膜中の厚さ方向において、合金メッキ被膜表面側から２０％以下の領域
Ｂ 領域Ａと領域Ｃに挟まれた領域 DESCRIPTION OF SYMBOLS 1,11 Conductive fine particle 2,12 Core material particle 3,13 Alloy plating film 4,14 Alloy plating film surface a Area | region of 20% or less from the core material particle side in the thickness direction in an alloy plating film b Alloy plating film In the thickness direction, 80% or less of the area from the surface of the alloy plating film A In the thickness direction of the alloy plating film, in the area of 20% or less from the core particle side C In the thickness direction of the alloy plating film, Area of 20% or less from the surface of the alloy plating film B Area between area A and area C

Claims (7)

芯材粒子の表面に無電解メッキ法によりニッケル、銅、及びリンを含有する合金メッキ被膜が形成されている導電性微粒子であって、
合金メッキ被膜中の厚さ方向において、芯材粒子側から２０％以下の領域でニッケル、及びリンを含有し、銅を含有せず、合金メッキ被膜表面側から８０％以下の領域でニッケル、銅、及びリンを含有することを特徴とする導電性微粒子。 Conductive fine particles in which an alloy plating film containing nickel, copper, and phosphorus is formed on the surface of the core material particles by an electroless plating method,
In the thickness direction in the alloy plating film, nickel and phosphorus are contained in the region of 20% or less from the core particle side, copper is not contained, and nickel and copper are contained in the region of 80% or less from the alloy plating film surface side. , and conductive fine particles you characterized by containing phosphorus. 合金メッキ被膜中の厚さ方向において、芯材粒子側から２０％以下の領域で合金メッキ組成中に８〜１５重量％のリンを含有し、合金メッキ被膜表面側から８０％以下の領域で合金メッキ組成中に０．０５〜５重量％のリンを含有することを特徴とする請求項１記載の導電性微粒子。 In the thickness direction in the alloy plating film, the alloy plating composition contains 8 to 15% by weight of phosphorus in the region of 20% or less from the core particle side, and in the region of 80% or less from the alloy plating film surface side. 2. The conductive fine particles according to claim 1, wherein the gold plating composition contains 0.05 to 5% by weight of phosphorus. 合金メッキ被膜中の厚さ方向において、合金メッキ被膜表面側から８０％以下の領域で合金メッキ組成中に０．５〜９０重量％の銅を含有することを特徴とする請求項１記載の導電性微粒子。 2. The conductive film according to claim 1 , wherein the alloy plating composition contains 0.5 to 90% by weight of copper in a region of 80% or less from the surface side of the alloy plating film in the thickness direction in the alloy plating film. Fine particles. 合金メッキ被膜中の厚さ方向において、芯材粒子側から２０％以下の領域で合金メッキ組成中に８５〜９２重量％のニッケルを含有し、合金メッキ被膜表面側から８０％以下の領域で合金メッキ組成中に５〜９９．４５重量％のニッケルを含有することを特徴とする請求項１記載の導電性微粒子。 In the thickness direction in the alloy plating film, the alloy plating composition contains 85 to 92% by weight of nickel in the region of 20% or less from the core particle side, and 80% or less in the region of the alloy plating film surface side. The conductive fine particles according to claim 1 , wherein the gold plating composition contains 5 to 99.45 wt% of nickel. 更に、合金メッキ被膜の表面に金被膜が形成されていることを特徴とする請求項１、２、３又は４記載の導電性微粒子。 5. The conductive fine particle according to claim 1 , wherein a gold film is formed on the surface of the alloy plating film. 金属触媒を担持させた芯材粒子の水性懸濁液に、ニッケル塩、リン系還元剤、及びｐＨ調整剤を含み、銅塩を含まないメッキ液を添加して初期無電解メッキ反応を行い、その後、ニッケル塩、銅塩、リン系還元剤、及びｐＨ調整剤を含むメッキ液を添加して後期無電解メッキ反応を行うことを特徴とする請求項１、２、３、４又は５記載の導電性微粒子の製造方法。 To an aqueous suspension of the metal catalyst the core particles supporting, nickel salts, phosphorus-based reducing agent, and viewed including a pH adjusting agent, performs the initial electroless plating reaction by adding a plating solution containing no copper salt , then, nickel salts, copper salts, phosphorus-based reducing agent, and claims 1, 2, 3, 4 or 5, wherein the plating solution was added to perform late electroless plating reactions containing pH adjusting agent Manufacturing method of conductive fine particles. 請求項１、２、３、４又は５記載の導電性微粒子が樹脂バインダーに分散されてなることを特徴とする異方性導電材料。 6. An anisotropic conductive material, wherein the conductive fine particles according to claim 1, 2, 3, 4 or 5 are dispersed in a resin binder.
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