JP2013229240A - Conductive particle and method for producing the same - Google Patents
Conductive particle and method for producing the same Download PDFInfo
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本発明は、安価で、導電性及び導電安定性に優れた導電性粒子、及び導電性粒子の製造方法に関する。 The present invention relates to a conductive particle that is inexpensive and excellent in conductivity and conductivity stability, and a method for producing the conductive particle.
導電性粒子は、バインダ樹脂や粘接着剤等と混合、混練することにより、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の異方性導電材料として広く用いられている。 The conductive particles are mixed and kneaded with a binder resin, an adhesive, etc., for example, anisotropic conductive paste, anisotropic conductive ink, anisotropic conductive adhesive, anisotropic conductive film, Widely used as anisotropic conductive materials such as anisotropic conductive sheets.
これらの異方性導電材料は、例えば、液晶ディスプレイ、パーソナルコンピュータ、携帯電話等の電子機器において、基板同士を電気的に接続したり、半導体素子等の小型部品を基板に電気的に接続したりするために、相対向する基板や電極端子の間に挟み込んで使用されている。 These anisotropic conductive materials are, for example, for electrically connecting substrates in electronic devices such as liquid crystal displays, personal computers, and mobile phones, and electrically connecting small components such as semiconductor elements to the substrate. In order to do so, it is used by being sandwiched between opposing substrates and electrode terminals.
これらの導電性粒子としては、従来、粒径が均一で、適度な強度を有する樹脂微粒子等の非導電性粒子の表面に、導電性膜として金属めっき被膜層を形成させた導電性粒子が開示されている（例えば、特許文献１参照）。 Conventionally disclosed as these conductive particles are conductive particles in which a metal plating film layer is formed as a conductive film on the surface of non-conductive particles such as resin fine particles having a uniform particle size and appropriate strength. (For example, refer to Patent Document 1).
従来の主流の表示素子である液晶ディスプレイ（ＬＣＤ）に比べて高品位、広視野角なディスプレイとして有機発光ダイオードディスプレイ（ＯＬＥＤ）の検討が進んでいるが、ＬＣＤ素子のスイッチングと比較し、自家発光するＯＬＥＤ素子は消費電力が大きく、且つ、素子の明るさは印加される電圧の変化に影響を受ける。
ＬＣＤ、ＯＬＥＤの素子と素子駆動用のＩＣは回路接続材料によって電気的に接合されるため、高品位なＯＬＥＤを提供するためには、ＬＣＤ素子の回路接続に用いられている回路接続材料よりも低抵抗でなおかつ長期において抵抗値変化の小さい回路接続材料が必要となる。
また、現在既に広く普及しているＬＣＤと同程度の価格が求められるため、ＯＬＥＤに用いられる回路接続材料にも同様に低コストが求められる。
Organic light-emitting diode displays (OLEDs) are being studied as high-definition and wide-viewing-angle displays compared to liquid crystal displays (LCDs), which are conventional mainstream display elements. OLED elements that consume large power consumption and the brightness of the elements are affected by changes in the applied voltage.
Since the LCD and OLED elements and the IC for driving the element are electrically joined by the circuit connection material, in order to provide a high-quality OLED, the circuit connection material used for the circuit connection of the LCD element is used. A circuit connection material having a low resistance and a small change in resistance value over a long period is required.
Further, since the same price as the LCD that is already widely used is required, the circuit connection material used for the OLED is also required to be low in cost.
本発明は、上記事情に鑑み、安価で、導電性及び導電安定性に優れた導電性粒子、及びその製造方法を提供することを目的とする。 An object of this invention is to provide the electroconductive particle which was cheap and excellent in electroconductivity and electroconductivity stability, and its manufacturing method in view of the said situation.
本発明は、バインダ樹脂及び導電性微粉末から少なくとも構成される複合粒子と、該複合粒子の表面に形成された少なくとも１層の金属めっき層と、を有する導電性粒子であって、前記導電性微粉末の平均粒径が、前記複合粒子の平均粒径の０．０００２〜０．６倍である、導電性粒子を提供する。 The present invention is a conductive particle having composite particles composed at least of a binder resin and conductive fine powder, and at least one metal plating layer formed on the surface of the composite particle, Provided is a conductive particle in which the average particle size of the fine powder is 0.0002 to 0.6 times the average particle size of the composite particles.
本発明の導電性粒子によれば、安価で、導電性及び導電安定性に優れる。かかる導電性粒子によりこのような効果が奏される理由は必ずしも明らかでないが、本発明者らは、導電性粒子のめっき部分のみならず、導電性微粉末を介して粒子の内部でも導電経路が形成されることが、その理由の一つであると考えている。 According to the electroconductive particle of this invention, it is cheap and is excellent in electroconductivity and electroconductivity stability. The reason why such an effect is exerted by such conductive particles is not necessarily clear, but the present inventors have not only a plated portion of the conductive particles but also a conductive path inside the particles through the conductive fine powder. We believe that one of the reasons is that it is formed.
前記金属めっき層のうちの１層がニッケルを含有することが好ましい。
前記導電性微粉末の前記複合粒子に対する体積比が２０〜９９体積％であることが好ましい。
前記バインダ樹脂は非水溶性弾性樹脂を含有することが好ましく、水溶性樹脂をさらに含有することがより好ましい。
前記非水溶性弾性樹脂のガラス転移温度（Ｔｇ）は−３０℃〜１１０℃であることが好ましい。
前記導電性微粉末はカーボンブラックであることが好ましく、中空シェル構造を有するカーボンブラックであることがより好ましい。
前記導電性粒子の表面に、前記複合粒子の平均粒径の１／３〜１／１００の高さの凹凸を有することが好ましい。
It is preferable that one of the metal plating layers contains nickel.
The volume ratio of the conductive fine powder to the composite particles is preferably 20 to 99% by volume.
The binder resin preferably contains a water-insoluble elastic resin, and more preferably further contains a water-soluble resin.
The glass transition temperature (Tg) of the water-insoluble elastic resin is preferably −30 ° C. to 110 ° C.
The conductive fine powder is preferably carbon black, more preferably carbon black having a hollow shell structure.
It is preferable that the surface of the conductive particles has irregularities with a height of 1/3 to 1/100 of the average particle diameter of the composite particles.
前記金属めっき層が、さらにパラジウムを含有するめっき層を有することが好ましい。
前記ニッケルを含有する金属めっき層の前記複合粒子側の表面から、前記ニッケルを含有する金属めっき層の厚さの２０％までの領域における金属めっき組成中に７〜１５質量％のリンを含有し、前記ニッケルを含有する金属めっき層の最表面から、前記ニッケルを含有する金属めっき層の厚さの１０％までの領域における金属めっき組成中に０．１〜３質量％のリンを含有することが好ましい。
前記導電性粒子は、平均粒径２０〜５００ｎｍの絶縁性微粒子を表面に有することが好ましい。
It is preferable that the metal plating layer further has a plating layer containing palladium.
7-15 mass% phosphorus is contained in the metal plating composition in the area | region from the surface by the side of the said composite particle of the said metal plating layer containing nickel to 20% of the thickness of the said metal plating layer containing nickel. In the metal plating composition in the region from the outermost surface of the metal plating layer containing nickel to 10% of the thickness of the metal plating layer containing nickel, 0.1 to 3% by mass of phosphorus is contained. Is preferred.
The conductive particles preferably have insulating fine particles having an average particle size of 20 to 500 nm on the surface.
本発明はまた、導電性微粉末及びバインダ樹脂が媒体中で混合されている組成物を噴霧して、前記バインダ樹脂及び前記導電性微粉末から少なくとも構成される複合粒子を製造する工程と、該複合粒子の表面に、少なくとも１層の金属めっき層を形成する工程とを備え、前記導電性微粉末の前記複合粒子に対する体積比が２０〜９９体積％である、導電性粒子の製造方法を提供する。 The present invention also includes a step of spraying a composition in which a conductive fine powder and a binder resin are mixed in a medium to produce composite particles composed of at least the binder resin and the conductive fine powder; Forming a metal plating layer on the surface of the composite particles, and providing a method for producing conductive particles, wherein a volume ratio of the conductive fine powder to the composite particles is 20 to 99% by volume. To do.
かかる製造方法によれば、安価で、導電性及び導電安定性に優れる導電性粒子を提供することができる。 According to this production method, it is possible to provide conductive particles that are inexpensive and excellent in conductivity and conductivity stability.
前記導電性微粉末は炭素系導電材料であることが好ましい。
前記導電性粒子の平均粒径は５０μｍ以下であることが好ましい。
前記バインダ樹脂は非水溶性弾性樹脂を含有することが好ましく、水溶性樹脂をさらに含有することがより好ましい。
前記炭素系導電材料の平均粒径は１０ｎｍ〜７００ｎｍであることが好ましい。また、前記非水溶性弾性樹脂は、平均粒径５０ｎｍ〜７００ｎｍの粒子状の樹脂であることが好ましい。
The conductive fine powder is preferably a carbon-based conductive material.
The average particle size of the conductive particles is preferably 50 μm or less.
The binder resin preferably contains a water-insoluble elastic resin, and more preferably further contains a water-soluble resin.
The carbon-based conductive material preferably has an average particle size of 10 nm to 700 nm. The water-insoluble elastic resin is preferably a particulate resin having an average particle size of 50 nm to 700 nm.
本発明にれば、安価で、導電性及び導電安定性に優れた導電性粒子、及びその製造方法を提供することができる。 According to the present invention, it is possible to provide conductive particles that are inexpensive and have excellent conductivity and conductivity stability, and a method for producing the same.
以下に実施例を掲げて本発明を実施するための形態を説明するが、本発明はこれら実施形態のみに限定されるものではない。 Hereinafter, modes for carrying out the present invention will be described with reference to examples, but the present invention is not limited only to these embodiments.
本実施形態の導電粒子は、バインダ樹脂及び導電性微粉末から少なくとも構成される複合粒子と、該複合粒子の表面に形成された少なくとも１層の金属めっき層と、を有する導電性粒子であって、前記導電性微粉末の平均粒径が、前記複合粒子の平均粒径の０．０００２〜０．６倍である。導電性微粉末は複合粒子中に分散されていることが好ましい。 The conductive particles of the present embodiment are conductive particles having at least composite particles composed of a binder resin and conductive fine powder, and at least one metal plating layer formed on the surface of the composite particles. The average particle size of the conductive fine powder is 0.0002 to 0.6 times the average particle size of the composite particles. The conductive fine powder is preferably dispersed in the composite particles.
ここで、本明細書中、平均粒径とは、レーザー回折・散乱法によって求めた粒度分布における積算値５０％での粒径（メディアン径Ｄ５０）を意味する。また、粒子が通常凝集体として存在する場合には、一次粒径の平均を意味する。 Here, in this specification, the average particle diameter means a particle diameter (median diameter D50) at an integrated value of 50% in a particle size distribution obtained by a laser diffraction / scattering method. Moreover, when a particle | grain exists normally as an aggregate, it means the average of a primary particle size.
上記導電性微粉末は、複合粒子の平均粒径の０．０００２〜０．６倍の平均粒径の導電体であれば特に限定されない。炭素系導電材料は複合粒子への分散性の観点から好ましく、炭素系導電材料として導電性が高いカーボンナノチューブやカーボンブラック、中空シェル構造を有するケッチェンブラックは特に好ましい。金、銀、白金等の貴金属類やパラジウム、銅等の導電性微粉末は比抵抗が小さいため、導電性の観点から好ましい。また、ニッケル、コバルト、モリブデン、タングステン等、比抵抗が１０×１０Ｅ−８Ωｍ以下と小さく且つ、ビッカース硬度が４００Ｈｖ以上の硬い金属微粒子の場合、複合粒子が変形しても形状変化が少なく、一度、形成した導通経路が保持されやすいため、特に好ましい。また、種類の異なる複数の導電性微粉末を混合して使用することもできる。 The conductive fine powder is not particularly limited as long as it is a conductor having an average particle size 0.0002 to 0.6 times the average particle size of the composite particles. A carbon-based conductive material is preferable from the viewpoint of dispersibility in composite particles, and carbon nanotubes and carbon black having high conductivity, and ketjen black having a hollow shell structure are particularly preferable as the carbon-based conductive material. Since noble metals such as gold, silver and platinum and conductive fine powders such as palladium and copper have low specific resistance, they are preferable from the viewpoint of conductivity. Further, in the case of hard metal fine particles such as nickel, cobalt, molybdenum, tungsten, etc., having a specific resistance as small as 10 × 10E-8 Ωm or less and a Vickers hardness of 400 Hv or more, there is little change in shape even if the composite particles are deformed. Since the formed conduction | electrical_connection path | route is easy to be hold | maintained, it is especially preferable. Also, a plurality of different types of conductive fine powders can be mixed and used.
また、上記導電性微粉末の形状は平均粒径が複合粒子の０．０００２〜０．６倍であれば特に限定されない。球状の導電性微粉末は複合粒子が変形したときに粉末表面に均一に圧力がかかるため、微粉末の形状変化が発生しにくいため、抵抗変化がしにくい。また、針状や鱗片状や多孔質微粉末は球形微粉末と比較して低比重のため、期待の効果を得るために必要な微粉末重量が軽くて済むため、好ましい。
複合粒子中の導電性微粉末の含有量は、複合粒子の真比重から求められる体積総量に対し、２０〜９９体積％の範囲が好ましく、４０〜８０体積％の範囲がより好ましい。２０体積％以下の場合、複合粒子中に分散した導電性微粉末間が接触して導通経路を形成する確率が大きく低下し、導通性が損なわれる。また、９９％以上になると導電性微粉末を支持するバインダの量が少なく、機械的強度が低下し、外力によって容易に破砕してしまう。
The shape of the conductive fine powder is not particularly limited as long as the average particle size is 0.0002 to 0.6 times that of the composite particles. Since the spherical conductive fine powder uniformly applies pressure to the powder surface when the composite particles are deformed, the shape change of the fine powder hardly occurs, and therefore the resistance change hardly occurs. In addition, needle-like, scaly, and porous fine powders are preferable because they have a lower specific gravity than spherical fine powders, and thus the weight of fine powders required to obtain the expected effect can be reduced.
The content of the conductive fine powder in the composite particles is preferably in the range of 20 to 99% by volume and more preferably in the range of 40 to 80% by volume with respect to the total volume determined from the true specific gravity of the composite particles. In the case of 20% by volume or less, the probability that conductive fine powders dispersed in the composite particles come into contact with each other to form a conduction path is greatly reduced, and the conductivity is impaired. On the other hand, if it is 99% or more, the amount of the binder supporting the conductive fine powder is small, the mechanical strength is lowered, and it is easily crushed by an external force.
上記バインダ樹脂としては特に限定されず、例えば、ポリエチレン、ポリプロピレン、ポリスチレン、ポリ塩化ビニル、ポリ塩化ビニリデン、ポリテトラフルオロエチレン、ポリイソブチレン、ポリブタジエン等のポリオレフィン；ポリメチルメタクリレート、ポリメチルアクリレート等のアクリル樹脂；ジビニルベンゼン重合樹脂；ジビニルベンゼン−スチレン共重合体、ジビニルベンゼン−アクリル酸エステル共重合体、ジビニルベンゼン−メタクリル酸エステル共重合体等のジビニルベンゼン系共重合樹脂；ポリアルキレンテレフタレート、ポリスルホン、ポリカーボネート、ポリアミド、フェノールホルムアルデヒド樹脂、メラミンホルムアルデヒド樹脂、ベンゾグアナミンホルムアルデヒド樹脂、尿素ホルムアルデヒド樹脂等が挙げられる。 The binder resin is not particularly limited. For example, polyolefins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polytetrafluoroethylene, polyisobutylene, and polybutadiene; acrylic resins such as polymethyl methacrylate and polymethyl acrylate Divinylbenzene polymer resin; divinylbenzene-styrene copolymer, divinylbenzene-acrylic acid ester copolymer, divinylbenzene-methacrylic acid ester copolymer and other divinylbenzene copolymer resins; polyalkylene terephthalate, polysulfone, polycarbonate, Polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, etc. It is.
上記複合粒子は、上記バインダ樹脂の原料モノマー及び硬化剤を水中に分散させて行う懸濁重合やパール重合の際に、重合系に所定量の導電性微粉末を一緒に分散することで得ることができる。
また、上記バインダ樹脂の原料モノマーに導電性微粉末を分散したものを加熱若しくは紫外線等により硬化させ、これを粉砕、分級することにより所望の径の粒子を得ることができる。
また、上記バインダ樹脂の原料モノマーに導電性微粉末を分散し、塗工機等でフィルム化し、加熱若しくは紫外線等にてモノマーを反応させたフィルムを粉砕し、分級により所望の径の粒子を得ることができる。
また、上記バインダ樹脂を溶融若しくは溶剤に溶解し、そこに導電性微粉末を所定量分散し、塗工機等でフィルム化し、フィルムを粉砕し、分級により所望の径の粒子を得ることができる。
使用する導電性微粉末が磁性体の場合、上記フィルム化の際に、上下方向に磁石により磁場を印加することで、上下方向に導電性微粉末を配列させることができる。
The composite particles are obtained by dispersing a predetermined amount of conductive fine powder together in a polymerization system during suspension polymerization or pearl polymerization in which the raw material monomer and curing agent of the binder resin are dispersed in water. Can do.
Also, particles having a desired diameter can be obtained by curing a material obtained by dispersing conductive fine powder in the above-mentioned binder resin raw material monomer by heating or ultraviolet rays, and then pulverizing and classifying it.
Also, conductive fine powder is dispersed in the above-mentioned binder resin raw material monomer, formed into a film with a coating machine, etc., and the film reacted with the monomer by heating or ultraviolet rays is pulverized to obtain particles of a desired diameter by classification. be able to.
In addition, the binder resin is melted or dissolved in a solvent, and a predetermined amount of conductive fine powder is dispersed therein, formed into a film with a coating machine or the like, and the film is pulverized to obtain particles having a desired diameter by classification. .
When the conductive fine powder to be used is a magnetic substance, the conductive fine powder can be arranged in the vertical direction by applying a magnetic field with a magnet in the vertical direction when forming the film.
また、導電性微粉末とバインダ樹脂とが媒体中で混合されており、複合粒子総量に対する導電性微粉末の体積比が２０〜９９体積％である組成物を噴霧して、媒体を揮発させると共に、バインダ樹脂で導電性微粉末を接合しつつ造粒する造粒法で作成することができる。
この場合、バインダ樹脂は非水溶性弾性樹脂を含有することが好ましい。また、非水溶性弾性樹脂は、粒子状の樹脂であることが好ましく、その粒径は、５０ｎｍ〜７００ｎｍであることが好ましい。非水溶性弾性樹脂はエマルジョン又はラテックス粒子として提供することができることから、複合粒子の製造の容易性の点から有利である。なお、弾性樹脂とは、動的粘弾性測定による弾性率が１０５〜１０９Ｐａ（好ましくは１０５〜１０８Ｐａ）である樹脂（動的弾性率の測定周波数は例えば１０Ｈｚ）をいい、弾性樹脂はこの弾性率を、室温（２５℃）で示すことが好ましい。
In addition, the conductive fine powder and the binder resin are mixed in the medium, and a composition in which the volume ratio of the conductive fine powder to the total amount of the composite particles is 20 to 99% by volume is sprayed to volatilize the medium. It can be prepared by a granulation method in which the conductive fine powder is granulated while being bonded with a binder resin.
In this case, the binder resin preferably contains a water-insoluble elastic resin. The water-insoluble elastic resin is preferably a particulate resin, and the particle size is preferably 50 nm to 700 nm. Since the water-insoluble elastic resin can be provided as emulsion or latex particles, it is advantageous from the viewpoint of ease of production of the composite particles. The elastic resin refers to a resin whose elastic modulus by dynamic viscoelasticity measurement is 10 5 to 10 9 Pa (preferably 10 5 to 10 8 Pa) (the measurement frequency of the dynamic elastic modulus is 10 Hz, for example) The elastic resin preferably exhibits this elastic modulus at room temperature (25 ° C.).
非水溶性弾性樹脂としては、ガラス転移温度（Ｔｇ）が−３０℃〜１１０℃の樹脂が有用である。Ｔｇがこのような温度範囲にあることで、実装時の変形に対する追随が容易となり、導電性接続材料に配合したときに、高い導電性を確保できる。なお、Ｔｇは、溶媒を乾燥した自立フィルムを作成し、所定の大きさに裁断した試料を、示差走査熱量計（ＤＳＣ）を用いて、開始温度−１００℃、昇温速度１０℃／分の条件で測定することができる。 As the water-insoluble elastic resin, a resin having a glass transition temperature (Tg) of −30 ° C. to 110 ° C. is useful. When Tg is in such a temperature range, it is easy to follow deformation during mounting, and high conductivity can be ensured when blended with a conductive connecting material. In addition, Tg created the self-supporting film which dried the solvent, and cut | disconnected the sample cut to the predetermined magnitude | size using a differential scanning calorimeter (DSC). It can be measured under conditions.
非水溶性弾性樹脂としては、例えば、スチレン・ブタジエン系ゴム、ポリブタジエン系ゴム、アクリロニトリル・ブタジエン系ゴム等が挙げられる。これらのゴム粒子は、１種類のみ又は２種類以上を混合して用いることができる。なお、ゴム成分としては、カルボキシル基等で変性されたものも採用でき、このようなゴム成分は親水性、混合性、密着性等に優れる。 Examples of the water-insoluble elastic resin include styrene / butadiene rubber, polybutadiene rubber, acrylonitrile / butadiene rubber, and the like. These rubber particles can be used alone or in combination of two or more. In addition, what was modified | denatured by the carboxyl group etc. as a rubber component can also be employ | adopted, and such a rubber component is excellent in hydrophilic property, mixing property, adhesiveness, etc.
ゴム粒子は、単層構造のものでも多層構造（コアシェル構造等）のものでもよい。また、中空構造のものも採用可能である。 The rubber particles may have a single layer structure or a multilayer structure (core-shell structure or the like). A hollow structure can also be used.
非水溶性弾性樹脂として、ガラス転移温度（Ｔｇ）が低いゴム粒子を選択することにより、弾性率の小さい（柔らかい）導電性複合粒子を設計することができ、Ｔｇが高いゴム粒子を選択すると、弾性率の大きい（固い）導電性複合粒子を設計することができる。また、Ｔｇの異なるゴム粒子をブレンドすることにより、所望の弾性率を有する導電性複合粒子を調整することもできる。 By selecting rubber particles having a low glass transition temperature (Tg) as the water-insoluble elastic resin, it is possible to design conductive composite particles having a low elastic modulus (soft). When rubber particles having a high Tg are selected, It is possible to design conductive composite particles having a large elastic modulus (hard). In addition, conductive composite particles having a desired elastic modulus can be adjusted by blending rubber particles having different Tg.
適度な弾性率を有する導電性複合粒子を設計する観点からは、ゴム成分のＴｇは、−３０〜１１０℃であることが好ましく、０℃〜１１０℃であることがより好ましく、１０℃〜１１０℃であることが特に好ましい。 From the viewpoint of designing conductive composite particles having an appropriate elastic modulus, the Tg of the rubber component is preferably -30 to 110 ° C, more preferably 0 ° C to 110 ° C, and 10 ° C to 110 ° C. It is particularly preferable that the temperature is C.
多層構造のゴム粒子や、複数のゴム粒子の混合物の場合、Ｔｇが複数生じる場合があるが、そのような場合は、いずれかのＴｇが上記範囲内に入っていればよい。 In the case of a rubber particle having a multilayer structure or a mixture of a plurality of rubber particles, a plurality of Tg may be generated. In such a case, any Tg may be within the above range.
ゴム粒子を２種類以上ブレンドして使用する場合において、例えば、弾性率を大きく（固く）し、更に、粒径を大きくしたい場合、高Ｔｇのゴム粒子と低Ｔｇのゴム粒子をブレンドして、機能を分担させ、高Ｔｇゴム粒子により弾性率を大きくし、タック性の大きい低Ｔｇのゴム粒子により粒径を大きくすることもできる。 In the case where two or more kinds of rubber particles are blended and used, for example, to increase the elastic modulus (hardness) and further increase the particle size, blend high Tg rubber particles and low Tg rubber particles, The function can be shared, the elastic modulus can be increased by the high Tg rubber particles, and the particle size can be increased by the low Tg rubber particles having a large tack property.
また、造粒法に用いるバインダ樹脂は水溶性樹脂をさらに含有するようにしてもよい。水溶性樹脂は造粒助剤として機能し得ることから、複合粒子の製造がより容易となり、導電性粒子の変形に対する追随性に優れ、より導電性が高い導電性粒子が得られる。 Further, the binder resin used in the granulation method may further contain a water-soluble resin. Since the water-soluble resin can function as a granulation aid, it is easier to produce composite particles, and it is possible to obtain conductive particles having excellent followability to deformation of the conductive particles and higher conductivity.
すなわち、導電性粒子の弾性をより大きく（固く）したい場合、上述した高Ｔｇゴム粒子と低Ｔｇゴム粒子とのブレンドでは、高弾性化とμｍサイズ粒子の造粒の両立に限界が生じる。この場合、第３成分として水に溶解が可能な水溶性樹脂を造粒助剤として配合することが可能である。これにより、タック性の乏しい高Ｔｇゴム粒子同士、導電性粒子同士又は高Ｔｇゴム粒子と導電性粒子の造粒が可能になり、高弾性化とμｍサイズの粒子化が可能となる。水溶性樹脂としては、分子量によって弾性率の調整が可能なポリビニルアルコール等を用いることが好適である。 That is, when it is desired to increase (harden) the elasticity of the conductive particles, the blend of the high Tg rubber particles and the low Tg rubber particles described above has a limit in achieving both high elasticity and granulation of μm size particles. In this case, it is possible to mix | blend water-soluble resin which can be melt | dissolved in water as a 3rd component as a granulation adjuvant. As a result, granulation of high Tg rubber particles having poor tackiness, between conductive particles, or between high Tg rubber particles and conductive particles is possible, and high elasticity and μm size particles can be obtained. As the water-soluble resin, it is preferable to use polyvinyl alcohol or the like whose elastic modulus can be adjusted by the molecular weight.
複合樹脂は、導電性微粉末とバインダ樹脂（非水溶性弾性樹脂を含有することが好ましく、造粒助剤としての水溶性樹脂を含有していてもよい）とを均一に混合し、バインダ樹脂で炭素系導電材料を接合して粒子化することにより得ることができる。 The composite resin is obtained by uniformly mixing a conductive fine powder and a binder resin (which preferably contains a water-insoluble elastic resin, and may contain a water-soluble resin as a granulating aid). It can be obtained by joining and carbonizing a carbon-based conductive material.
混合の方法としては、一般的な回転混合羽根を有する攪拌機にて上記成分を混合する方法や、超音波にて振動させ混合する方法又は攪拌混合と超音波振動を同時に行う方法等がある。使用成分が均一に混合したかどうかの判断は、例えば、混合物の粘度の測定（数箇所採取測定）や電子顕微鏡による観察、又は加熱による水分除去にて残る固形分量（数箇所採取測定）等で判断できる。 As a mixing method, there are a method of mixing the above components with a general stirrer having a rotary mixing blade, a method of mixing by vibrating with ultrasonic waves, a method of performing stirring and mixing and ultrasonic vibration simultaneously, or the like. Judgment of whether or not the components used are uniformly mixed is, for example, based on the measurement of the viscosity of the mixture (sampling measurement at several points), observation with an electron microscope, or the amount of solid content remaining after removing water by heating (sampling measurement at several points). I can judge.
複合粒子の製造は、噴霧材料を乾燥し、熱的に複合、造粒させる装置で行なうことが好ましい。特に、液状混合物噴霧装置、噴霧物乾燥装置及び乾燥物回収装置を有した装置を使用して行なうことが、安価で安定な製造が可能であることから効果的である。 The production of the composite particles is preferably carried out with an apparatus for drying the spray material and thermally compositing and granulating it. In particular, it is effective to use a device having a liquid mixture spraying device, a sprayed material drying device, and a dried material recovery device because it can be manufactured at low cost and stably.
具体的には、導電性微粉末とバインダ樹脂とが媒体中で混合された組成物（複合粒子に対する導電性微粉末の体積比が２０〜９９体積％）を噴霧して、媒体を揮発させると共に、バインダ樹脂で導電性微粉末を接合しつつ造粒する方法が採用できる。 Specifically, a composition in which conductive fine powder and binder resin are mixed in a medium (a volume ratio of the conductive fine powder to the composite particles is 20 to 99% by volume) is sprayed to volatilize the medium. A method of granulating while bonding conductive fine powder with a binder resin can be adopted.
上記組成物の噴霧及び上記媒体の揮発を効率的に行なうために、組成物が吐出される孔と圧搾空気が吐出される孔とを有するノズルを用い、１００〜２００℃に保たれた乾燥室に向けて、組成物及び圧搾空気を同時に吐出することが好適である。 In order to efficiently spray the composition and volatilize the medium, a drying chamber maintained at 100 to 200 ° C. using a nozzle having a hole through which the composition is discharged and a hole through which compressed air is discharged. For this, it is preferable to discharge the composition and compressed air simultaneously.
なお、得られた複合粒子に更なる耐熱性や強度を付与したい場合、得られた複合粒子を熱処理する手段を実施してもよい。熱処理は、加熱炉を使用し炉内温度１００℃〜１５０℃で１時間程度処理を行うことで実施できる。このようにすることで、造粒時にゴムの架橋成分が未処理で残存したとしても、架橋を進めることができる。 In addition, when giving further heat resistance and intensity | strength to the obtained composite particle, you may implement the means to heat-process the obtained composite particle. The heat treatment can be carried out by performing a treatment for about 1 hour at a furnace temperature of 100 ° C. to 150 ° C. using a heating furnace. By doing in this way, even if the rubber crosslinking component remains untreated during granulation, the crosslinking can proceed.
より均一な粒度が要求される場合、得られた複合粒子を分級することができる。分級の方法としては、例えば、サイクロン分級等が挙げられる。 When a more uniform particle size is required, the obtained composite particles can be classified. Examples of the classification method include cyclone classification.
なお、導電性微粉末の２５℃における導電率は、１Ｓ／ｃｍ以上であることが好ましく、５Ｓ／ｃｍ以上であることがより好ましく、２０Ｓ／ｃｍ以上であることが特に好ましく、３０Ｓ／ｃｍ以上であることが最も好ましい。導電率の上限は高いほど良く、金属で最も導電率が高い銅では５６×１０Ｅ６Ｓ／ｃｍであり、超伝導物質は∞となる。 The conductivity of the conductive fine powder at 25 ° C. is preferably 1 S / cm or more, more preferably 5 S / cm or more, particularly preferably 20 S / cm or more, and 30 S / cm or more. Most preferably. The higher the upper limit of the conductivity, the better. The copper having the highest conductivity among metals is 56 × 10E6 S / cm, and the superconducting material is ∞.
上記導電性粒子の２５℃における導電率は、例えば、粉体抵抗測定装置により、粉体専用プローブ（４探針、リング電極）を用いて、任意の圧力下で粉体の体積抵抗率を測定することで算出できる。 The conductivity of the conductive particles at 25 ° C. is measured by measuring the volume resistivity of the powder under an arbitrary pressure using a powder dedicated probe (4 probes, ring electrode), for example, with a powder resistance measuring device. Can be calculated.
上記複合粒子の平均粒径としては特に限定されないが、好ましい下限は１μｍ、好ましい上限は５０μｍである。１μｍ未満であると、例えば、無電解めっきをする際に凝集しやすく、単粒子としにくくなることがあり、５０μｍを超えると、異方性導電材料として基板電極間等で用いられる範囲を超えてしまうことがある。より好ましい上限は２０μｍである。 The average particle size of the composite particles is not particularly limited, but a preferred lower limit is 1 μm and a preferred upper limit is 50 μm. If it is less than 1 μm, for example, it is likely to aggregate when electroless plating is performed, and it may be difficult to form single particles. If it exceeds 50 μm, it exceeds the range used between substrate electrodes as an anisotropic conductive material. May end up. A more preferred upper limit is 20 μm.
上記複合粒子表面に設けられるめっき層の材質は導電性が良好な物質であれば特に限定されない。導電性の観点からは金、銀、銅等の導電率が高い金属、又はこれらの合金であることが好ましい。また、回路接続材料の導電性粒子として用いる場合には、回路接続時の圧力に対して回路接続材料のバインダ樹脂を排除するに十分な硬さをもったニッケルまたはニッケル合金が好適に用いられる。また、めっき硬さと高い導電率を両立するためニッケルめっきと導電率が高い金属を複数層積層しためっき層を有することもできる。
本発明で複合粒子表面に設けられるめっき層は無電解めっき、置換めっき、電気めっき、還元めっき、スパッタリング等の従来公知の方法で形成することができる。
The material of the plating layer provided on the surface of the composite particle is not particularly limited as long as the material has good conductivity. From the viewpoint of conductivity, a metal having high conductivity such as gold, silver, copper, or an alloy thereof is preferable. When used as conductive particles of a circuit connection material, nickel or a nickel alloy having a hardness sufficient to eliminate the binder resin of the circuit connection material with respect to the pressure at the time of circuit connection is suitably used. Moreover, in order to make plating hardness and high electrical conductivity compatible, it can also have the plating layer which laminated | stacked multiple layers of nickel plating and the metal with high electrical conductivity.
In the present invention, the plating layer provided on the surface of the composite particles can be formed by a conventionally known method such as electroless plating, displacement plating, electroplating, reduction plating or sputtering.
本発明の導電性粒子表面に複合粒子の平均粒径の１／３〜１／１００の凹凸を有することで回路接続材料の導電性粒子として用いる際に、回路接続材料のバインダ樹脂を導電性粒子表面と回路表面の間の空間から効率的に除去することができ、回路の接続抵抗と経時変化をさらに抑制することが可能となる。 When the conductive particles of the present invention have irregularities that are 1/3 to 1/100 of the average particle diameter of the composite particles, the binder resin of the circuit connection material is used as the conductive particles when used as the conductive particles of the circuit connection material. It is possible to efficiently remove the space between the surface and the circuit surface, and it is possible to further suppress the connection resistance of the circuit and the change with time.
前記凹凸は複合粒子表面に目的の凹凸の大きさと同じ大きさの平均粒径を有する微粒子を付着させ、その上からめっき層を形成することで得られる。また、造粒法で作成した複合粒子は表面に凹凸を有するため、このままめっき処理を行うことで特段の前処理を行わなくても凹凸を形成することができるため、経済上、好ましい。
また、金属めっきの際、例えば、最初に使用しためっき液に、これよりも濃度の高いめっき液を追加することでめっき液濃度を不均一にすることに形成することもできる。
The irregularities can be obtained by attaching fine particles having an average particle size of the same size as the desired irregularities on the surface of the composite particles and forming a plating layer thereon. Moreover, since the composite particle produced by the granulation method has an unevenness on the surface, the unevenness can be formed without performing a special pretreatment by performing the plating treatment as it is, which is preferable from an economical viewpoint.
Further, when metal plating is performed, for example, the plating solution concentration can be made non-uniform by adding a plating solution having a higher concentration to the plating solution used first.
前記めっき層のうち、ニッケルを含有するめっき層（ニッケルめっき層）を有する場合、ニッケルめっきにリンを含有することができる。この場合、前記複合粒子表面から２０％以下の膜厚領域で金属めっき組成中に７〜１５重量％のリンを含有し、金属めっき被覆表面側から金属めっき被膜膜厚の１０％以下の領域で金属めっき組成中に０．1〜３重量％のリンを含有し、金属めっき被膜層全体は７重量％以上のリンを含有することで高い導電性を維持しながら磁性を押さえることで単分散性が良好となる。さらに、金属めっき被覆表面側から金属めっき被膜膜厚の１０％以下の領域で金属めっき組成中に０．1〜３重量％のリンを含有することで、金若しくはパラジウムを含有するめっき層（金めっき層若しくはパラジウムめっき層）を均一に形成し、緻密で連続した、下地のニッケルが露出していない構造となる極めて導電性の優れた導電性粒子とすることができる。なお、良好な導電性を確保するためには、金属めっき被膜層全体に対するリンの含有率は１５重量％以下であることが好ましい。 When the plating layer has a nickel-containing plating layer (nickel plating layer), the nickel plating can contain phosphorus. In this case, the metal plating composition contains 7 to 15% by weight of phosphorus in a film thickness region of 20% or less from the composite particle surface, and in a region of 10% or less of the metal plating film thickness from the metal plating coating surface side. The metal plating composition contains 0.1 to 3% by weight of phosphorus, and the entire metal plating film layer contains 7% by weight or more of phosphorus, thereby maintaining high conductivity and suppressing the magnetism. Becomes better. Furthermore, by containing 0.1 to 3% by weight of phosphorus in the metal plating composition in a region of 10% or less of the metal plating film thickness from the surface of the metal plating coating, a plating layer containing gold or palladium (gold (Plating layer or palladium plating layer) can be uniformly formed, and conductive particles having excellent conductivity can be obtained which are dense and continuous and have a structure in which the underlying nickel is not exposed. In addition, in order to ensure favorable electroconductivity, it is preferable that the content rate of phosphorus with respect to the whole metal plating film layer is 15 weight% or less.
上記複合粒子表面から２０％以下の膜厚領域で金属めっき組成中含リン率の好ましい下限が７重量％、好ましい上限が１５重量％である。７重量％未満であると、ニッケルめっき層が硬くなりすぎ、割れやすくなることがあり、さらに磁性による凝集が発生し、分散性が悪くなることがあり、１５重量％を超えると、ニッケルめっき層が軟らかくなりすぎ、複合粒子と導電層との密着性が低下することがある。 The preferable lower limit of the phosphorus content in the metal plating composition is 7% by weight and the preferable upper limit is 15% by weight in the film thickness region of 20% or less from the surface of the composite particles. If it is less than 7% by weight, the nickel plating layer becomes too hard and may be easily cracked, and further, aggregation due to magnetism may occur and dispersibility may be deteriorated. If it exceeds 15% by weight, the nickel plating layer May become too soft, and the adhesion between the composite particles and the conductive layer may decrease.
金属めっき被覆表面側から金属めっき被膜膜厚の１０％以下の領域で金属めっき組成中含リン率の好ましい下限が０.１重量％、好ましい上限が３重量％である。３重量％を超えると、ニッケルめっき被膜の結晶構造が粗くなり、緻密で連続した金めっき若しくはパラジウムめっき層を形成することができないことがある。 The preferable lower limit of the phosphorus content in the metal plating composition is 0.1% by weight and the preferable upper limit is 3% by weight in the region of 10% or less of the metal plating film thickness from the surface of the metal plating coating. If it exceeds 3% by weight, the crystal structure of the nickel plating film becomes rough, and a dense and continuous gold plating or palladium plating layer may not be formed.
上記金属めっき組成中に０．１〜３重量％のリンを含有する好ましい膜厚領域は、金属めっき被覆表面側から１０％以下の膜厚領域である。０．１〜３重量％のリンを含有する金属めっきは、強磁性体であるため、金属めっき被覆表面側から１０％を超える膜厚であると、磁性による凝集が発生し、分散性が悪くなることがある。 A preferable film thickness region containing 0.1 to 3% by weight of phosphorus in the metal plating composition is a film thickness region of 10% or less from the metal plating coating surface side. Since the metal plating containing 0.1 to 3% by weight of phosphorus is a ferromagnetic material, if the film thickness is more than 10% from the surface of the metal plating coating, aggregation due to magnetism occurs and the dispersibility is poor. May be.
本実施形態において、導電性粒子のめっき最外層の表面に配置され、粒径が２０〜５００ｎｍである絶縁性微粒子を有することが好ましい。絶縁性粒子は、有機化合物でも無機酸化物でもその両方を混合しても良好な特性が得られる。 In this embodiment, it is preferable to have insulating fine particles that are disposed on the surface of the outermost layer of conductive particles and have a particle size of 20 to 500 nm. The insulating particles can obtain good characteristics even when both organic compounds and inorganic oxides are mixed.
絶縁性微粒子の平均粒径は、複合粒子より小さいことが好ましい。具体的には、２０〜５００ｎｍであることが好ましい。なお、絶縁性微粒子の粒径は、ＢＥＴ法による比表面積換算法またはＸ線小角散乱法で測定される。平均粒径が２０ｎｍ未満であると、パラジウム粒子に吸着した絶縁性微粒子が絶縁膜として作用せずに、電極間の一部にショートを発生させる傾向がある。一方、粒径が５００ｎｍを超えると、電極間で導電性が得られない傾向がある。 The average particle size of the insulating fine particles is preferably smaller than the composite particles. Specifically, it is preferably 20 to 500 nm. The particle size of the insulating fine particles is measured by the specific surface area conversion method by the BET method or the X-ray small angle scattering method. If the average particle size is less than 20 nm, the insulating fine particles adsorbed on the palladium particles do not act as an insulating film and tend to cause a short circuit between a part of the electrodes. On the other hand, when the particle diameter exceeds 500 nm, there is a tendency that conductivity cannot be obtained between the electrodes.
本実施形態の導電性粒子のめっき層の総厚の好ましい下限は４０ｎｍ、好ましい上限が２５０ｎｍである。４０ｎｍ未満であると、所望の導電性が得られないことがあり、２５０ｎｍを超えると、前記導電層とコア粒子の密着性が低下し、剥離しやすくなる。粒径にも影響を与える。導電性が確保され、かつ粒径にも影響をきたさない４０ｎｍ〜２５０ｎｍであることが好ましい。 The preferable lower limit of the total thickness of the plating layer of the conductive particles of this embodiment is 40 nm, and the preferable upper limit is 250 nm. When the thickness is less than 40 nm, desired conductivity may not be obtained. When the thickness exceeds 250 nm, the adhesiveness between the conductive layer and the core particles is reduced, and the film is easily peeled off. It also affects the particle size. The conductivity is preferably 40 nm to 250 nm, which does not affect the particle size.
パラジウムめっき層は延性を有するため、導電性微粉末を圧縮した後に、金属割れを起こし難く、金属割れに起因するマイグレーションが起こり難い。また、パラジウムは金及び白金と同様に導電性に優れているが、これらの貴金属を同体積で比較した場合、パラジウムが最も安価であり、実用的である。これらの理由から、最外層はパラジウム層であることが好適である。パラジウム層を有することで、導電層の酸化防止、接続抵抗の低減化、表面の安定化等を図ることもできる。 Since the palladium plating layer has ductility, after compressing the conductive fine powder, it is difficult to cause metal cracking, and migration due to metal cracking is unlikely to occur. Palladium is excellent in conductivity like gold and platinum, but when these noble metals are compared in the same volume, palladium is the cheapest and practical. For these reasons, the outermost layer is preferably a palladium layer. By having a palladium layer, it is possible to prevent oxidation of the conductive layer, reduce connection resistance, stabilize the surface, and the like.
上記パラジウムめっき層は、パラジウムとリンの合金であってもよい。パラジウムが合金である場合、導電性の観点から、合金中のパラジウム含有率は７０重量％以上であることが好ましく、９０重量％〜１００重量％未満であることがさらに好ましい。 The palladium plating layer may be an alloy of palladium and phosphorus. When palladium is an alloy, from the viewpoint of conductivity, the palladium content in the alloy is preferably 70% by weight or more, and more preferably 90% by weight to less than 100% by weight.
上記パラジウムめっき層の厚さは、１０ｎｍ〜５０ｎｍであることが好ましい。パラジウムめっき層の厚さが１０ｎｍ未満であると導電層の酸化を防止することが困難であり、接続抵抗値が高く、十分な導電性を得られないことがある。一方、パラジウムの厚さが５０ｎｍを超えると導電性粒子全体の弾性が低下する傾向にある。また、パラジウムめっき層が厚いほど、コストが高くなり、経済的にそぐわない。 The thickness of the palladium plating layer is preferably 10 nm to 50 nm. When the thickness of the palladium plating layer is less than 10 nm, it is difficult to prevent oxidation of the conductive layer, the connection resistance value is high, and sufficient conductivity may not be obtained. On the other hand, when the thickness of palladium exceeds 50 nm, the elasticity of the entire conductive particles tends to decrease. In addition, the thicker the palladium plating layer, the higher the cost and the lower the cost.
本実施形態の導電性粒子を製造する際には、複合粒子の表面に金属めっき組成中に７〜１５重量％のリンを含有するニッケルめっき層を形成し、その後、金属めっき組成中に０．1〜３重量％のリンを含有するニッケルめっき層を形成する順番でめっきを行えばよい。上記７〜１５重量％のリンを含有するニッケルめっき層又は０．1〜３重量％のリンを含有するニッケルめっき層を形成させる方法としては、例えば、めっき反応のｐＨを制御する方法、ニッケルめっき液中のリン濃度を制御する方法等が挙げられる。なかでも、反応制御に優れていることから、めっき反応のｐＨを制御する方法が好適に用いられる。 When producing the conductive particles of the present embodiment, a nickel plating layer containing 7 to 15% by weight of phosphorus in the metal plating composition is formed on the surface of the composite particles, and then 0. Plating may be performed in the order of forming a nickel plating layer containing 1 to 3% by weight of phosphorus. Examples of the method for forming the nickel plating layer containing 7 to 15% by weight of phosphorus or the nickel plating layer containing 0.1 to 3% by weight of phosphorus include, for example, a method for controlling the pH of the plating reaction, nickel plating Examples include a method for controlling the phosphorus concentration in the liquid. Especially, since it is excellent in reaction control, the method of controlling the pH of plating reaction is used suitably.
以下に、各工程を詳述する。本実施形態の導電性粒子の製造方法は、複合粒子の表面に触媒付与を行う工程を有する。上記触媒付与を行う方法としては、たとえば、複合粒子の表面を調整し、分散性やめっき触媒付き性、めっき付き性を確保する前処理を行う。前処理方法としては、アルカリ性又は酸性の脱脂、界面活性剤による親水化処理、コア粒子表面に官能基を付与する改質処理などが上げられる。これら、前処理を行った後には、複合粒子表面に無電解めっきの還元反応の核となる触媒を付与する触媒化工程を施す。無電解ニッケルめっきの触媒としては、パラジウムや金、白金などが主に用いられる。触媒を付与する具体的な方法としては、イオン化もしくは安定な錯体化したパラジウム触媒溶液中に前処理済みの複合粒子を投入し、分散および攪拌することで、複合粒子表面に錯体化したパラジウムなどの触媒を付与する。これを、還元して金属パラジウムを複合粒子表面に付与する。また、アルカリ脱脂後に酸中和した複合粒子を、二塩化スズ溶液に浸漬しセンシタイジングを行い、二塩化パラジウム溶液に浸漬してアクチベイジングを行う触媒付与の方法も一般的に知られている。 Below, each process is explained in full detail. The manufacturing method of the electroconductive particle of this embodiment has the process of providing a catalyst to the surface of a composite particle. As a method for applying the catalyst, for example, the surface of the composite particles is adjusted, and a pretreatment for ensuring dispersibility, plating catalyst adhesion, and plating adhesion is performed. Examples of the pretreatment method include alkaline or acidic degreasing, a hydrophilic treatment with a surfactant, and a modification treatment for imparting a functional group to the surface of the core particle. After performing these pretreatments, a catalytic step for imparting a catalyst as a nucleus of a reduction reaction of electroless plating to the composite particle surface is performed. As the electroless nickel plating catalyst, palladium, gold, platinum or the like is mainly used. As a specific method for imparting the catalyst, the pretreated composite particles are put into an ionized or stable complexed palladium catalyst solution, dispersed and stirred, and the like, such as palladium complexed on the surface of the composite particles. Apply catalyst. This is reduced to give metallic palladium to the composite particle surface. Also known is a method of applying a catalyst in which composite particles that have been acid neutralized after alkaline degreasing are immersed in a tin dichloride solution for sensitizing and then immersed in a palladium dichloride solution for activation. Yes.
本実施形態の導電性粒子の製造方法は、例えば、無電解ニッケルめっき液を用い、複合粒子の表面に、ニッケルめっき反応時のｐＨ、錯化剤、次亜リン酸・水酸化ナトリウム濃度等のめっき液組成を厳密に調整することにより、リン濃度の組成を変更させた導電性微粉末を得ることができる。無電解ニッケルめっき液には、錯化剤にクエン酸、リンゴ酸、コハク酸、プロピオン酸、乳酸、及びこれらの塩からなる群より選ばれる少なくとも1種のなるものを使用し、かつ、ｐＨを５．５以下に調整することにより７〜１５重量％のリン濃度を得ることができる。また、次亜リン酸と水酸化ナトリウム濃度比を調整することでリン濃度を変更することができるということが知られている。 The method for producing conductive particles of the present embodiment uses, for example, an electroless nickel plating solution, and on the surface of the composite particles, such as pH during nickel plating reaction, complexing agent, hypophosphorous acid / sodium hydroxide concentration, etc. By strictly adjusting the plating solution composition, it is possible to obtain a conductive fine powder in which the phosphorus concentration composition is changed. For the electroless nickel plating solution, at least one selected from the group consisting of citric acid, malic acid, succinic acid, propionic acid, lactic acid, and salts thereof is used as the complexing agent, and the pH is adjusted. A phosphorus concentration of 7 to 15% by weight can be obtained by adjusting to 5.5 or less. It is also known that the phosphorus concentration can be changed by adjusting the concentration ratio of hypophosphorous acid and sodium hydroxide.
０．１〜３重量％のリン含有ニッケルめっき層を持つ導電性粒子の製造方法は、上記の方法でリン濃度を調整することが可能であるが、例えば、ニッケルめっき反応時のｐＨを５．５以上に調整することにより０．１〜３重量％のリン含有ニッケルめっき層を形成させることができる。 In the method for producing conductive particles having a 0.1 to 3% by weight phosphorus-containing nickel plating layer, the phosphorus concentration can be adjusted by the above method. For example, the pH at the time of nickel plating reaction is 5. By adjusting to 5 or more, a 0.1 to 3 weight% phosphorus containing nickel plating layer can be formed.
以下、本発明を実施例に基づいて詳細に説明するが、本発明はこれに限定されるものではない。 EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to this.
（実施例１）
（１）複合粒子用材料の調製
ゴム粒子として、日本ゼオン株式会社製ラテックスゴム、商品名：Ｎｉｐｏｌ ＬＸ４３０（スチレン・ブタジエンゴム、平均粒径：１５０ｎｍ、Ｔｇ：１２℃、ゴム固形分：４８％）：１００ｇ（ゴム成分：４８ｇ）、及び、炭素系導電材料として、ライオン株式会社製水分散系ケッチェンブラック、商品名：ライオンペーストＷ−３１１Ｎ（平均一次粒径：４０ｎｍ、水分散粒径：４００ｎｍ以下、ケッチェンブラック含有量８．１％）：１７７０ｇ（ケッチェンブラック量１４３．４ｇ）を秤量し（複合粒子に対するケッチェンブラックの真比重を用いた体積比が６３体積％）、更に純水３００ｇを追加した。得られた配合物を、攪拌羽根をセットしたモータで１時間攪拌混合し（室温：２５℃）、水分散型の複合粒子用材料を調製した。
Example 1
(1) Preparation of Composite Particle Material Latex rubber manufactured by Nippon Zeon Co., Ltd., trade name: Nipol LX430 (styrene / butadiene rubber, average particle size: 150 nm, Tg: 12 ° C., rubber solid content: 48%) : 100 g (rubber component: 48 g), and as a carbon-based conductive material, Lion Corporation water dispersion ketjen black, trade name: Lion Paste W-311N (average primary particle size: 40 nm, water dispersion particle size: 400 nm Hereinafter, Ketjen black content 8.1%): 1770 g (Ketjen black amount 143.4 g) was weighed (volume ratio using the true specific gravity of Ketjen black to composite particles was 63% by volume), and pure water Added 300 g. The resulting blend was stirred and mixed with a motor equipped with stirring blades for 1 hour (room temperature: 25 ° C.) to prepare a water-dispersed composite particle material.
（２）複合粒子の製造
スプレードライヤー装置（大川原化工機株式会社製、商品名：ＮＬ−５）を使用し、噴霧エア圧力：０．２ＭＰａ、乾燥装置入り口温度：２００℃、出口温度：９０℃、材料処理量：２．３ｋｇ／ｈの条件にて、上記（１）で調製した水分散型の複合粒子用材料を噴霧し、ゴム粒子及び炭素系導電材料から構成される複合粒子を得た。得られた複合粒子を分級して平均粒径５．３μｍの複合粒子を得た。得られた複合粒子の走査型電子顕微鏡（株式会社日立製作所製、商品名：Ｓ−４５００）写真を図１に示す。図１によれば、複合粒子の表面に、ゴム粒子とケッチェンブラックに起因する凹凸が形成されていることが分かる。
(2) Production of composite particles Using a spray dryer (Okawara Chemical Co., Ltd., trade name: NL-5), spraying air pressure: 0.2 MPa, drying device inlet temperature: 200 ° C, outlet temperature: 90 ° C The material processing amount: 2.3 kg / h, the water-dispersed composite particle material prepared in (1) was sprayed to obtain composite particles composed of rubber particles and a carbon-based conductive material. . The obtained composite particles were classified to obtain composite particles having an average particle size of 5.3 μm. A scanning electron microscope (manufactured by Hitachi, Ltd., trade name: S-4500) photograph of the obtained composite particles is shown in FIG. According to FIG. 1, it can be seen that irregularities due to rubber particles and ketjen black are formed on the surface of the composite particles.
（３）導電性粒子の製造
得られた複合粒子３ｇを、水酸化ナトリウム水溶液で脱脂し、酸で中和し表面調整を行った。表面調整された複合粒子を、アルカリパラジウム触媒であるアトテックネオガント８３４（アトテックジャパン株式会社製、商品名）を含有する溶液１００ｍＬ中に投入し、３５℃で１０分攪拌した後、直径３μｍのメンブレンフィルタ（ミリポア社製）で濾過した。粒子を２００ｍＬの蒸留水で水洗し、同様に濾過した。なお、一般的に、「アルカリパラジウム触媒」とは、粒子表面にニッケル層等のめっき層を形成するための触媒であって、パラジウム層そのものではない。
(3) Production of conductive particles 3 g of the obtained composite particles were degreased with an aqueous sodium hydroxide solution, neutralized with an acid, and the surface was adjusted. The surface-adjusted composite particles were put into 100 mL of a solution containing Atotech Neogant 834 (trade name, manufactured by Atotech Japan Co., Ltd.) which is an alkali palladium catalyst, stirred at 35 ° C. for 10 minutes, and then a membrane having a diameter of 3 μm. It filtered with the filter (made by Millipore). The particles were washed with 200 mL distilled water and filtered similarly. In general, the “alkali palladium catalyst” is a catalyst for forming a plating layer such as a nickel layer on the particle surface, not the palladium layer itself.
次に、水洗後の複合粒子を、７０℃、ｐＨ６．０に調整した３ｇ／Ｌの次亜リン酸ナトリウム水溶液に添加し、表面が活性化された複合粒子を得た。 Next, the composite particles after washing with water were added to a 3 g / L sodium hypophosphite aqueous solution adjusted to 70 ° C. and pH 6.0 to obtain composite particles whose surface was activated.
得られた複合粒子を、水１０００ｍＬ、及びリンゴ酸ナトリウム２０ｇ／Ｌが入った２０００ｍＬのガラスビーカーに投入し、超音波分散させた後、フッ素製攪拌羽根により攪拌（６００ｒｐｍ）を行いながらｐＨを５．５以下に調整し、８０℃に加温した。ここに、無電解ニッケルめっき液であるＳＥＫ６７０（日本カニゼン株式会社 製品名）を（ＳＥＫ６７０−０）／（ＳＥＫ６７０−１）＝１．８の割合で混合した初期薄膜めっき液を、定量ポンプを用いて７ｍＬ／ｍｉｎで添加したところ、約３０秒後に還元反応が開始し、浴中から気泡が発生した。このようにして初期薄膜形成を終了した後、間をあけずに硫酸ニッケル：２２４ｇ／Ｌ、リンゴ酸ナトリウム：３０５ｇ／Ｌを混合した厚付けめっき液ａと、次亜リン酸ナトリウム：５３４ｇ／Ｌ、水酸化ナトリウム：３４ｇ／Ｌで混合した厚付けめっき液ｂを１３ｍＬ／ｍｉｎで２液同時に添加した。その後、気泡の発生が停止するまで攪拌を行った。めっき浴は最終的にｐＨ＝４．０であった。その後、濾過を行い、蒸留水で水洗を３回実施し、４０℃の真空乾燥機で７時間乾燥した後、解砕して凝集を解し、ニッケルめっきが施された導電性粒子１を得た。得られた導電性粒子１の走査型電子顕微鏡写真を図２に示す。図２によれば、導電性粒子１の表面に凹凸が形成されていることが分かる。この凹凸は、上記複合粒子の凹凸を核としたものであると考えられる。
なお、電解ニッケルめっき液ＳＥＫ６７０は、還元剤として、主に次亜リン酸ナトリウムを含有している。
The obtained composite particles were put into a 2000 mL glass beaker containing 1000 mL of water and 20 g / L of sodium malate, and after ultrasonic dispersion, the pH was adjusted to 5 while stirring (600 rpm) with a fluorine stirring blade. The temperature was adjusted to 5 or less and heated to 80 ° C. The initial thin film plating solution in which SEK670 (product name of Nippon Kanisen Co., Ltd.), which is an electroless nickel plating solution, is mixed at a ratio of (SEK670-0) / (SEK670-1) = 1.8 is used with a metering pump. When the solution was added at a rate of 7 mL / min, the reduction reaction started after about 30 seconds, and bubbles were generated from the bath. After completing the initial thin film formation in this way, a thick plating solution a in which nickel sulfate: 224 g / L and sodium malate: 305 g / L were mixed with no gap, and sodium hypophosphite: 534 g / L. Sodium hydroxide: Thickening plating solution b mixed at 34 g / L was added simultaneously at 13 mL / min. Thereafter, stirring was performed until the generation of bubbles stopped. The plating bath was finally pH = 4.0. Thereafter, filtration is performed, and washing with distilled water is performed three times. After drying for 7 hours in a vacuum dryer at 40 ° C., the particles are crushed to break up agglomerates to obtain conductive particles 1 on which nickel plating has been applied. It was. A scanning electron micrograph of the obtained conductive particles 1 is shown in FIG. According to FIG. 2, it can be seen that irregularities are formed on the surface of the conductive particles 1. This unevenness is considered to be the core of the unevenness of the composite particle.
The electrolytic nickel plating solution SEK670 contains mainly sodium hypophosphite as a reducing agent.
（１）導電性測定
微小圧縮試験機（ＰＣＴ−２００型、島津製作所社製）を用いて、微小圧縮試験機の圧子とステンレステーブルに金線を接合して圧子とステンレステーブル間の抵抗を測定できるようにして、導電性粒子１の圧力を加える前の抵抗と５０％扁平させたときの抵抗を測定（測定数１００個）し、結果を表１に示した。
さらに、導電性粒子１を８５℃８５％ＲＨの高温高湿条件で１００時間処理した後に、同様の試験を行い、結果を表１に示した。
(1) Conductivity measurement Using a micro compression tester (PCT-200 type, manufactured by Shimadzu Corporation), a gold wire is joined to the indenter of the micro compression tester and a stainless steel table, and the resistance between the indenter and the stainless steel table is measured. The resistance before applying the pressure of the conductive particles 1 and the resistance when flattened by 50% were measured (number of measurements: 100), and the results are shown in Table 1.
Further, after the conductive particles 1 were treated at 85 ° C. and 85% RH under high temperature and high humidity conditions for 100 hours, the same test was performed and the results are shown in Table 1.
（２）導電性粒子の粒度分布測定
レーザー回折式粒度分布測定装置（株式会社島津製作所製、商品名：ＳＡＬＤ−３０００Ｊ）を使用し、導電性粒子１の粒度分布を測定し、メディアン径Ｄ５０を平均粒径とした。得られた平均粒径を表１に示した。
(2) Measurement of particle size distribution of conductive particles Using a laser diffraction particle size distribution measuring device (manufactured by Shimadzu Corporation, trade name: SALD-3000J), the particle size distribution of the conductive particles 1 is measured, and the median diameter D50 is determined. The average particle size was taken. The obtained average particle diameter is shown in Table 1.
（３）めっき層の評価
得られた導電性粒子１から、観察、分析に必要な部分の薄片を収束イオンビームで切り出した。透過型電子顕微鏡ＨＦ−２２００（株式会社日立製作所製 製品名）を用いて１０万倍以上で観察し、めっきの平均厚みを算出した。さらに、上記装置に付属したＮＯＲＡＮ社製ＥＤＸでめっき層の各領域の成分分析を行った。得られた値から各領域のニッケルめっき中に含まれるリンの濃度を算出し、その結果を表１に示した。
(3) Evaluation of plating layer From the obtained electroconductive particle 1, the thin piece of the part required for observation and analysis was cut out with the focused ion beam. Observation was performed at 100,000 times or more using a transmission electron microscope HF-2200 (product name, manufactured by Hitachi, Ltd.), and the average thickness of the plating was calculated. Furthermore, the component analysis of each area | region of the plating layer was performed by NORX EDX attached to the said apparatus. The concentration of phosphorus contained in the nickel plating in each region was calculated from the obtained values, and the results are shown in Table 1.
（実施例２）
複合粒子に対するケッチェンブラックの真比重を用いた体積比が２０体積％となるようにゴム粒子とケッチェンブラックの仕込み量を変更した以外は実施例１と同様にして導電性粒子２を得た。
(Example 2)
Conductive particles 2 were obtained in the same manner as in Example 1 except that the charged amounts of the rubber particles and the ketjen black were changed so that the volume ratio using the true specific gravity of the ketjen black to the composite particles was 20% by volume. .
（１）導電性測定
導電性粒子２の導電性を実施例１と同様に測定し、結果を表１に示した。
(1) Conductivity measurement The conductivity of the conductive particles 2 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（２）導電性粒子の粒度分布測定
導電性粒子２の粒度分布を実施例１と同様に測定し、結果を表１に示した。
(2) Measurement of particle size distribution of conductive particles The particle size distribution of the conductive particles 2 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（実施例３）
複合粒子に対するケッチェンブラックの真比重を用いた体積比が９９体積％となるようにゴム粒子とケッチェンブラックの仕込み量を変更した以外は実施例１と同様にして導電性粒子３を得た。
(Example 3)
Conductive particles 3 were obtained in the same manner as in Example 1 except that the charged amounts of rubber particles and ketjen black were changed so that the volume ratio using the true specific gravity of ketjen black to the composite particles was 99% by volume. .
（１）導電性測定
導電性粒子３の導電性を実施例１と同様に測定し、結果を表１に示した。
(1) Conductivity measurement The conductivity of the conductive particles 3 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（２）導電性粒子の粒度分布測定
導電性粒子３の粒度分布を実施例１と同様に測定し、結果を表１に示した。
(2) Measurement of particle size distribution of conductive particles The particle size distribution of the conductive particles 3 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（実施例４）
平均粒径１．０μｍの複合粒子を使用した以外は実施例１と同様にして導電性粒子４を得た。
Example 4
Conductive particles 4 were obtained in the same manner as in Example 1 except that composite particles having an average particle size of 1.0 μm were used.
（１）導電性測定
導電性粒子４の導電性を実施例１と同様に測定し、結果を表１に示した。
(1) Conductivity measurement The conductivity of the conductive particles 4 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（２）導電性粒子の粒度分布測定
導電性粒子４の粒度分布を実施例１と同様に測定し、結果を表１に示した。
(2) Measurement of particle size distribution of conductive particles The particle size distribution of the conductive particles 4 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（実施例５）
平均粒径５０μｍの複合粒子を使用した以外は実施例１と同様にして導電性粒子５を得た。
(Example 5)
Conductive particles 5 were obtained in the same manner as in Example 1 except that composite particles having an average particle size of 50 μm were used.
（１）導電性測定
導電性粒子５の導電性を実施例１と同様に測定し、結果を表１に示した。
(1) Conductivity measurement The conductivity of the conductive particles 5 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（２）導電性粒子の粒度分布測定
導電性粒子５の粒度分布を実施例１と同様に測定し、結果を表１に示した。
(2) Measurement of particle size distribution of conductive particles The particle size distribution of the conductive particles 5 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（実施例６）
ケッチェンブラックの代わりに平均粒径０．５μｍのカーボンナノチューブの真比重を用いた体積比が６３体積％となるように使用した以外は実施例１と同様にして導電性粒子６を得た。
(Example 6)
Conductive particles 6 were obtained in the same manner as in Example 1 except that the volume ratio using the true specific gravity of carbon nanotubes having an average particle diameter of 0.5 μm was 63 volume% instead of ketjen black.
（１）導電性測定
導電性粒子６の導電性を実施例１と同様に測定し、結果を表１に示した。
(1) Conductivity measurement The conductivity of the conductive particles 6 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（２）導電性粒子の粒度分布測定
導電性粒子６の粒度分布を実施例１と同様に測定し、結果を表１に示した。
(2) Measurement of particle size distribution of conductive particles The particle size distribution of the conductive particles 6 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（実施例７）
ケッチェンブラックの代わりに平均粒径０．２μｍの鱗片状銀粒子の真比重を用いた体積比が６３体積％となるように使用した以外は実施例１と同様にして導電性粒子７を得た。
(Example 7)
Conductive particles 7 were obtained in the same manner as in Example 1 except that the volume ratio using the true specific gravity of scale-like silver particles having an average particle diameter of 0.2 μm was 63 volume% instead of ketjen black. It was.
（１）導電性測定
導電性粒子７の導電性を実施例１と同様に測定し、結果を表１に示した。
(1) Conductivity measurement The conductivity of the conductive particles 7 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（２）導電性粒子の粒度分布測定
導電性粒子７の粒度分布を実施例１と同様に測定し、結果を表１に示した。
(2) Measurement of particle size distribution of conductive particles The particle size distribution of the conductive particles 7 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（実施例８）
ケッチェンブラックの代わりに平均粒径０．５μｍの鱗片状銀粒子を使用した以外は実施例７と同様にして導電性粒子８を得た。
(Example 8)
Conductive particles 8 were obtained in the same manner as in Example 7, except that scaly silver particles having an average particle size of 0.5 μm were used instead of ketjen black.
（１）導電性測定
導電性粒子８の導電性を実施例１と同様に測定し、結果を表１に示した。
(1) Conductivity measurement The conductivity of the conductive particles 8 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（２）導電性粒子の粒度分布測定
導電性粒子８の粒度分布を実施例１と同様に測定し、結果を表１に示した。
(2) Measurement of particle size distribution of conductive particles The particle size distribution of the conductive particles 8 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（実施例９）
（導電性粒子の製造）
テトラメチロールメタントリアクリレート６０重量部、ジビニルベンゼン２０重量部及びアクリロニトリル２０重量部を混合し、更に、得られる複合粒子に対する真比重を用いた体積比が６３体積％となるよう、ライオン株式会社製ケッチェンブラック、商品名：カーボンＥＣＰ６００ＪＤ（平均一次粒径：４０ｎｍ、粉末状）を添加し、ビーズミルを用いて４８時間かけてケッチェンブラックを分散させた。このケッチェンブラック粉末が分散された組成物に、過酸化ベンゾイル２重量部を混合し、これを３重量％濃度のポリビニルアルコール水溶液８５０重量部に投入し、よく攪拌した後、ホモジナイザーでこの重合性単量体液滴の粒径が約０．５〜３０μｍの微粒状に懸濁させ、懸濁液を得た。得られた懸濁液を、温度計と攪拌機と還流冷却器とを備えた２リットルのセパラブルフラスコに移し、窒素雰囲気中で攪拌しながら８５℃に昇温加熱し、７時間重合反応を行い、更に９０℃に昇温して３時間保ち、重合反応を完結させた。その後、重合反応液を冷却し、生成した粒子を濾過し、充分に水洗し乾燥させて、その後分級して、平均粒径５．６μｍの複合粒子を得た。この複合粒子を用いて実施例１と同様にニッケルめっきを施し、ニッケルめっきが施された導電性粒子９を得た。得られた導電性粒子９の走査型電子顕微鏡写真を図３に示す。図３によれば、導電性粒子９の表面が平滑であることが分かる。これは、懸濁重合で合成しているためと考えられる。
Example 9
(Manufacture of conductive particles)
60 parts by weight of tetramethylol methane triacrylate, 20 parts by weight of divinylbenzene and 20 parts by weight of acrylonitrile are mixed, and the volume ratio using the true specific gravity with respect to the resulting composite particles is 63% by volume. Chain black, trade name: Carbon ECP600JD (average primary particle size: 40 nm, powder) was added, and ketjen black was dispersed for 48 hours using a bead mill. 2 parts by weight of benzoyl peroxide is mixed with the composition in which the ketjen black powder is dispersed, and this is added to 850 parts by weight of a 3% by weight polyvinyl alcohol aqueous solution. Suspension was obtained by suspending the monomer droplets into fine particles having a particle size of about 0.5 to 30 μm. The obtained suspension was transferred to a 2 liter separable flask equipped with a thermometer, a stirrer, and a reflux condenser, heated to 85 ° C. with stirring in a nitrogen atmosphere, and subjected to a polymerization reaction for 7 hours. Further, the temperature was raised to 90 ° C. and maintained for 3 hours to complete the polymerization reaction. Thereafter, the polymerization reaction liquid was cooled, and the generated particles were filtered, washed thoroughly with water and dried, and then classified to obtain composite particles having an average particle size of 5.6 μm. Using these composite particles, nickel plating was performed in the same manner as in Example 1 to obtain conductive particles 9 subjected to nickel plating. A scanning electron micrograph of the conductive particles 9 obtained is shown in FIG. According to FIG. 3, it can be seen that the surface of the conductive particles 9 is smooth. This is thought to be due to the synthesis by suspension polymerization.
（１）導電性測定
導電性粒子９の導電性を実施例１と同様に測定し、結果を表１に示した。
(1) Conductivity measurement The conductivity of the conductive particles 9 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（２）導電性粒子の粒度分布測定
導電性粒子９の粒度分布を実施例１と同様に測定し、結果を表１に示した。
(2) Measurement of particle size distribution of conductive particles The particle size distribution of the conductive particles 9 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（３）めっき層の評価
導電性粒子９の各領域のニッケルおよびリンの濃度を実施例１と同様に算出し、結果を表１に示した。
(3) Evaluation of plating layer The concentrations of nickel and phosphorus in each region of the conductive particles 9 were calculated in the same manner as in Example 1, and the results are shown in Table 1.
（実施例１０）
実施例１において、ニッケルめっき処理及び濾過後に得られたニッケルめっきが施された導電性粒子１を、水１０００ｍＬ、及び酒石酸ナトリウム２０ｇ／Ｌが入った２０００ｍＬビーカーに投入し、超音波分散させた後、フッ素製攪拌羽根により攪拌（６００ｒｐｍ）を行いながらｐＨを６．０以上に調整し、８０℃に加温した。定量ポンプを用いて、硫酸ニッケル：２２４ｇ／Ｌ、酒石酸ナトリウム：２０ｇ／Ｌを混合した厚付けめっき液ｃと、次亜リン酸ナトリウム：２２６ｇ／Ｌ、水酸化ナトリウム：８５ｇ／Ｌで混合した厚付けめっき液ｄを１５ｍＬ／ｍｉｎで添加したところ、滴下直後に還元反応が開始し、浴中から気泡が発生した。めっき終了時の浴はｐＨ＝６．２であり、浴全体は灰色であった。濾過した後蒸留水で水洗を３回実施し４０℃の真空乾燥機で７時間乾燥した後、解砕して凝集を解し、導電性粒子１０を得た。
(Example 10)
In Example 1, the nickel-plated conductive particles 1 obtained after the nickel plating treatment and filtration were put into a 2000 mL beaker containing 1000 mL of water and 20 g / L of sodium tartrate, and subjected to ultrasonic dispersion. The pH was adjusted to 6.0 or higher while stirring (600 rpm) with a fluorine stirring blade and heated to 80 ° C. Using a metering pump, a thick plating solution c in which nickel sulfate: 224 g / L and sodium tartrate: 20 g / L were mixed with sodium hypophosphite: 226 g / L, sodium hydroxide: 85 g / L When the plating solution d was added at 15 mL / min, the reduction reaction started immediately after dropping, and bubbles were generated from the bath. The bath at the end of plating was pH = 6.2 and the entire bath was gray. After filtration, washed with distilled water three times, dried in a vacuum dryer at 40 ° C. for 7 hours, and then crushed to break up the aggregate to obtain conductive particles 10.
（１）導電性測定
導電性粒子１０の導電性を実施例１と同様に測定し、結果を表１に示した。
(1) Conductivity measurement The conductivity of the conductive particles 10 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（２）導電性粒子の粒度分布測定
導電性粒子１０の粒度分布を実施例１と同様に測定し、結果を表１に示した。
(2) Measurement of particle size distribution of conductive particles The particle size distribution of the conductive particles 10 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（３）めっき層の評価
導電性粒子１０の各領域のニッケルおよびリンの濃度を実施例１と同様に算出し、結果を表１に示した。
(3) Evaluation of plating layer The concentration of nickel and phosphorus in each region of the conductive particles 10 was calculated in the same manner as in Example 1, and the results are shown in Table 1.
（実施例１１）
無電解パラジウムめっき液であるパレット（小島化学薬品株式会社、製品名）を建浴し、フッ素製攪拌羽根で攪拌しながら７０℃に加温した。ここに、実施例１０で得られた導電性粒子１０を投入し５分めっきを実施した後、濾過と水洗を３回実施した。４０℃の真空乾燥機で７時間乾燥した後、解砕して凝集を解し、ニッケルめっき及びパラジウムめっきがこの順で施された導電性粒子１１を得た。
(Example 11)
A pallet (Kojima Chemical Co., Ltd., product name) which is an electroless palladium plating solution was erected and heated to 70 ° C. while stirring with a fluorine stirring blade. Here, the conductive particles 10 obtained in Example 10 were added, and after plating for 5 minutes, filtration and washing were performed three times. After drying in a vacuum dryer at 40 ° C. for 7 hours, the powder was crushed to break up the aggregates, and conductive particles 11 were obtained in which nickel plating and palladium plating were applied in this order.
（１）導電性測定
導電性粒子１１の導電性を実施例１と同様に測定し、結果を表１に示した。
(1) Conductivity measurement The conductivity of the conductive particles 11 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（２）導電性粒子の粒度分布測定
導電性粒子１１の粒度分布を実施例１と同様に測定し、結果を表１に示した。
(2) Measurement of particle size distribution of conductive particles The particle size distribution of the conductive particles 11 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（３）めっき層の評価
導電性粒子１１の各領域のニッケルおよびリンの濃度を実施例１と同様に算出し、結果を表１に示した。
(3) Evaluation of plating layer The concentration of nickel and phosphorus in each region of the conductive particles 11 was calculated in the same manner as in Example 1, and the results are shown in Table 1.
さらに、金属めっき被膜とパラジウム層の各領域の成分分析にＥＳＣＡ分析装置、ＡＸＩＳ−１６５型（島津製作所／Ｋｒａｔｏｓ社製 製品名）も使用した。導電性粒子１１をインジウム箔に固定し、金属めっき被膜とパラジウム層をＡｒエッチングにより序所に除去しながら、めっき層表面の成分分析を行った。Ａｒエッチングレートは５ｎｍ／ｍｉｎで、Ａｒエッチング１分毎に成分分析を行い、これを繰り返してめっき層の各領域の成分を算出した。ちなみに、パラジウムが検出されなくなった時点の値をニッケル最表面側、また複合粒子に由来する炭素が検出され、ニッケルの信号が減少し収束した時点を複合粒子表面として、めっき層中の各領域のニッケルおよびリン濃度として算出した。結果を表１に示す。 Further, an ESCA analyzer, AXIS-165 type (Shimadzu Corporation / Kratos product name) was also used for component analysis of each region of the metal plating film and the palladium layer. The conductive particles 11 were fixed to an indium foil, and component analysis of the plating layer surface was performed while removing the metal plating film and the palladium layer by Ar etching. The Ar etching rate was 5 nm / min, component analysis was performed every minute of Ar etching, and this was repeated to calculate the components in each region of the plating layer. By the way, the value at the time when palladium is no longer detected is the nickel outermost surface side, and the carbon derived from the composite particle is detected, and the point at which the nickel signal decreases and converges is defined as the composite particle surface. Calculated as nickel and phosphorus concentrations. The results are shown in Table 1.
（実施例１２）
（絶縁被覆処理）
ニッケルめっき及びパラジウムめっきがこの順で施された導電性粒子１１の表面に絶縁性微粒子であるシリカ微粒子を吸着させる絶縁被覆処理を、特開２００８−１２０９９０に公開されている方法で実施した。
(Example 12)
(Insulation coating treatment)
An insulating coating treatment for adsorbing silica fine particles as insulating fine particles on the surface of the conductive particles 11 subjected to nickel plating and palladium plating in this order was carried out by a method disclosed in Japanese Patent Application Laid-Open No. 2008-120990.
メルカプト酢酸８ｍｍｏｌをメタノール２００ｍＬに溶解させて反応液を調製した。 A reaction solution was prepared by dissolving 8 mmol of mercaptoacetic acid in 200 mL of methanol.
次に、導電性粒子１１を１ｇ上記反応液に加え、室温（２５℃）で２時間スリーワンモーターで攪拌した。メタノールで洗浄後、直径３μｍのメンブレンフィルタ（ミリポア社製）で濾過することで、表面にカルボキシル基を有する一次処理粒子１を得た。 Next, 1 g of conductive particles 11 was added to the reaction solution, and the mixture was stirred with a three-one motor at room temperature (25 ° C.) for 2 hours. After washing with methanol, the solution was filtered through a membrane filter having a diameter of 3 μm (manufactured by Millipore) to obtain primary treated particles 1 having a carboxyl group on the surface.
次に、分子量７００００の３０％ポリエチレンイミン水溶液（和光純薬工業（株）製）を超純水で希釈し、０．３重量％ポリエチレンイミン水溶液を得た。前記一次処理粒子１を０．３重量％ポリエチレンイミン水溶液に１ｇ加え、室温で１５分攪拌した。 Next, a 30% polyethyleneimine aqueous solution (manufactured by Wako Pure Chemical Industries, Ltd.) having a molecular weight of 70,000 was diluted with ultrapure water to obtain a 0.3 wt% polyethyleneimine aqueous solution. 1 g of the primary treated particles 1 was added to a 0.3% by weight aqueous polyethyleneimine solution and stirred at room temperature for 15 minutes.
その後、直径３μｍのメンブレンフィルタ（ミリポア社製）で一次処理粒子１をろ過し、超純水２００ｇに入れて室温で５分攪拌した。さらに直径３μｍのメンブレンフィルタ（ミリポア社製）で一次処理粒子１をろ過し、前記メンブレンフィルタ上にて２００ｇの超純水で２回洗浄を行うことで、一次処理粒子１に吸着していないポリエチレンイミンを除去した。 Thereafter, the primary treated particles 1 were filtered through a membrane filter having a diameter of 3 μm (manufactured by Millipore), and the mixture was placed in 200 g of ultrapure water and stirred at room temperature for 5 minutes. Further, the primary treated particles 1 are filtered through a membrane filter (manufactured by Millipore) having a diameter of 3 μm and washed twice with 200 g of ultrapure water on the membrane filter, whereby polyethylene not adsorbed on the primary treated particles 1 is obtained. The imine was removed.
次に、絶縁性微粒子であるコロイダルシリカの分散液（質量濃度２０％、扶桑化学工業（株）製、製品名：クオートロンＰＬ−１０、平均粒径１００ｎｍ）を超純水で希釈して０．１重量％シリカ分散溶液を得た。前記ポリエチレンイミンでの処理後の一次処理粒子１を０．１重量％シリカ分散溶液に入れて室温で１５分攪拌した。 Next, a dispersion of colloidal silica, which is an insulating fine particle (mass concentration 20%, manufactured by Fuso Chemical Industry Co., Ltd., product name: Quatron PL-10, average particle size 100 nm) is diluted with ultrapure water. A 1% by weight silica dispersion was obtained. The primary treated particles 1 after the treatment with the polyethyleneimine were put into a 0.1 wt% silica dispersion solution and stirred at room temperature for 15 minutes.
次に、直径３μｍのメンブレンフィルタ（ミリポア社製）で一次処理粒子１をろ過し、超純水２００ｇに入れて室温で５分攪拌した。さらに直径３μｍのメンブレンフィルタ（ミリポア社製）で一次処理粒子１をろ過し、前記メンブレンフィルタ上にて２００ｇの超純水で２回洗浄を行うことで、一次処理粒子１に吸着していないシリカを除去した。その後８０℃で３０分の条件で乾燥を行い、１２０℃で１時間加熱乾燥行うことで、導電性粒子１１（母粒子）の表面にシリカ（子粒子）が吸着した、表面が絶縁処理された導電性粒子１２を得た。 Next, the primary treated particles 1 were filtered with a membrane filter (manufactured by Millipore) having a diameter of 3 μm, put in 200 g of ultrapure water, and stirred at room temperature for 5 minutes. Further, the primary treated particles 1 are filtered through a membrane filter having a diameter of 3 μm (manufactured by Millipore) and washed twice with 200 g of ultrapure water on the membrane filter, whereby silica that is not adsorbed on the primary treated particles 1 Was removed. Thereafter, drying was performed at 80 ° C. for 30 minutes, and heat drying was performed at 120 ° C. for 1 hour, whereby silica (child particles) was adsorbed on the surface of the conductive particles 11 (mother particles), and the surface was insulated. Conductive particles 12 were obtained.
（１）導電性測定
導電性粒子１２の導電性を実施例１と同様に測定し、結果を表１に示した。
(1) Conductivity measurement The conductivity of the conductive particles 12 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（２）導電性粒子の粒度分布測定
導電性粒子１２の粒度分布を実施例１と同様に測定し、結果を表１に示した。
(2) Measurement of particle size distribution of conductive particles The particle size distribution of the conductive particles 12 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（比較例１）
ケッチェンブラックを使用しない以外は実施例１と同様にして導電性粒子１３を得た。
(Comparative Example 1)
Conductive particles 13 were obtained in the same manner as in Example 1 except that ketjen black was not used.
（１）導電性測定
導電性粒子１３の導電性を実施例１と同様に測定し、結果を表１に示した。
(1) Conductivity measurement The conductivity of the conductive particles 13 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（２）導電性粒子の粒度分布測定
導電性粒子１３の粒度分布を実施例１と同様に測定し、結果を表１に示した。
(2) Measurement of particle size distribution of conductive particles The particle size distribution of the conductive particles 13 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（比較例２）
ゴム粒子を使用しない以外は実施例１と同様にして導電性粒子１４を得た。
(Comparative Example 2)
Conductive particles 14 were obtained in the same manner as in Example 1 except that no rubber particles were used.
（１）導電性測定
導電性粒子１４の導電性を実施例１と同様に測定し、結果を表１に示した。
(1) Conductivity measurement The conductivity of the conductive particles 14 was measured in the same manner as in Example 1, and the results are shown in Table 1.
（２）導電性粒子の粒度分布測定
導電性粒子１４の粒度分布を実施例１と同様に測定し、結果を表１に示した。
(2) Measurement of particle size distribution of conductive particles The particle size distribution of the conductive particles 14 was measured in the same manner as in Example 1, and the results are shown in Table 1.
表１に記載の領域Ａとは、ニッケルめっき層の、複合粒子側から２０％以下の領域である。領域Ｂとは、ニッケルめっき層の、最表面側から１０％以下の領域である。 The region A described in Table 1 is a region of 20% or less from the composite particle side of the nickel plating layer. The region B is a region of 10% or less from the outermost surface side of the nickel plating layer.
実施例１〜１１で作製した粒子は全て、無変形時抵抗が１０Ω以下となり、良好な抵抗値を示した。また、５０％変形時の抵抗の無変形時抵抗からの低下の割合は比較例と比較して大きい。これは導電性粒子の変形に伴い、複合粒子中の導電性微粉末同士が接触し、新たな導通経路が形成されたためと考えられる。 All of the particles produced in Examples 1 to 11 had an undeformed resistance of 10Ω or less, indicating a good resistance value. Further, the rate of decrease in resistance at the time of 50% deformation from the resistance at the time of no deformation is larger than that of the comparative example. This is presumably because the conductive fine powder in the composite particles contacted each other with the deformation of the conductive particles, and a new conduction path was formed.
また、表面に絶縁粒子を配置した実施例１２は無変形時抵抗が高いにも拘わらず、５０％変形時抵抗は他の実施例と同等となった。これは無加圧下の無変形時は抵抗測定の端子と導電性粒子のめっきの間に絶縁粒子が存在するため抵抗が高くなるが、圧力を加えて粒子を偏平させると圧力によって、絶縁粒子は端子と導電性粒子めっきの間から排除され、端子と導電粒子のめっきが直接接触するためと考えられる。本粒子は、無加圧下で高い絶縁性を示すため、回路接続材料の導電粒子とし使用した場合、絶縁性を保持する必要のある隣接回路間にて高い絶縁性を達成できることが期待される。 Further, in Example 12, in which insulating particles were arranged on the surface, the resistance at 50% deformation was equal to that of the other examples, although the resistance at no deformation was high. This is because when there is no deformation under no pressure, the resistance increases because there are insulating particles between the resistance measurement terminal and the conductive particle plating, but when the particles are flattened by applying pressure, the insulating particles This is because it is excluded from between the terminal and the conductive particle plating, and the terminal and the conductive particle plating are in direct contact with each other. Since the present particles exhibit high insulation under no pressure, when used as conductive particles of a circuit connecting material, it is expected that high insulation can be achieved between adjacent circuits that need to maintain insulation.
以上説明したように、本発明は、コストが安く、極めて導電性及び導電安定性に優れた導電性粒子、及び導電性粒子の製造方法に関する。 As described above, the present invention relates to conductive particles that are low in cost and extremely excellent in conductivity and conductivity stability, and a method for producing conductive particles.
Claims (19)
前記導電性微粉末の平均粒径が、前記複合粒子の平均粒径の０．０００２〜０．６倍である、導電性粒子。 Conductive particles having composite particles composed of at least a binder resin and conductive fine powder, and at least one metal plating layer formed on the surface of the composite particles,
The electroconductive particle whose average particle diameter of the said electroconductive fine powder is 0.0002 to 0.6 times the average particle diameter of the said composite particle.
該複合粒子の表面に、少なくとも１層の金属めっき層を形成する工程とを備え、
前記導電性微粉末の前記複合粒子に対する体積比が２０〜９９体積％である、導電性粒子の製造方法。 Spraying a composition in which a conductive fine powder and a binder resin are mixed in a medium to produce composite particles composed at least of the binder resin and the conductive fine powder;
Forming at least one metal plating layer on the surface of the composite particles,
The manufacturing method of electroconductive particle whose volume ratio with respect to the said composite particle of the said electroconductive fine powder is 20-99 volume%.
The conductive adhesive which made the adhesive agent contain the electroconductive particle as described in any one of Claims 1-12.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015149313A (en) * | 2014-02-04 | 2015-08-20 | 日立化成株式会社 | Adhesive for electronic device and method of bonding electronic device |
| JP2016037512A (en) * | 2014-08-05 | 2016-03-22 | デクセリアルズ株式会社 | Anisotropic conductive adhesive, method for producing the same, connection structure and method for producing the same |
| JP2016171014A (en) * | 2015-03-13 | 2016-09-23 | 東洋インキＳｃホールディングス株式会社 | Conductive paste for laser processing and use of the same |
| WO2020093556A1 (en) * | 2018-11-09 | 2020-05-14 | 深圳市华星光电技术有限公司 | Anisotropic conductive adhesive and conducting film thereof |
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2012
- 2012-04-26 JP JP2012101627A patent/JP2013229240A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015149313A (en) * | 2014-02-04 | 2015-08-20 | 日立化成株式会社 | Adhesive for electronic device and method of bonding electronic device |
| JP2016037512A (en) * | 2014-08-05 | 2016-03-22 | デクセリアルズ株式会社 | Anisotropic conductive adhesive, method for producing the same, connection structure and method for producing the same |
| JP2016171014A (en) * | 2015-03-13 | 2016-09-23 | 東洋インキＳｃホールディングス株式会社 | Conductive paste for laser processing and use of the same |
| WO2020093556A1 (en) * | 2018-11-09 | 2020-05-14 | 深圳市华星光电技术有限公司 | Anisotropic conductive adhesive and conducting film thereof |
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