JP2011070944A - Manufacturing method for conductive particulates, and the conductive particulates - Google Patents
Manufacturing method for conductive particulates, and the conductive particulates Download PDFInfo
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Abstract
Description
本発明は、基材となる樹脂粒子との密着性の高い金属層を形成することができる導電性微粒子の製造方法に関する。また、本発明は、該導電性微粒子の製造方法を用いて製造される導電性微粒子に関する。 The present invention relates to a method for producing conductive fine particles capable of forming a metal layer having high adhesion to resin particles serving as a substrate. The present invention also relates to conductive fine particles produced using the method for producing conductive fine particles.
基材粒子の表面に導電層を有する導電性微粒子は、例えば、異方性導電フィルムや異方性導電ペースト等の異方性導電材料や、Ｂａｌｌ Ｇｒｉｄ Ａｒｒａｙ（ＢＧＡ）実装用はんだボール等の実装用接続材料に広く利用されている。 The conductive fine particles having the conductive layer on the surface of the base particle are, for example, an anisotropic conductive material such as an anisotropic conductive film or an anisotropic conductive paste, or a mounting ball such as a ball grid array (BGA) mounting solder ball. Widely used for connecting materials.
異方性導電材料や実装用接続材料に用いられる導電性微粒子の接続信頼性は、導電性微粒子の導電層の密着性に大きく依存する。導電層の密着性が低い導電性微粒子を相対向する回路基板や電極端子の間に接続した場合、接続のために必要な圧力や熱に由来する応力によって導電層が割れやすくなる。その結果、接続端子間の導通不良や断線が起こりやすくなる。
しかしながら、導電性微粒子は、通常、基材粒子の表面への無電解めっき、又は、無電解めっきの後に電解めっきを行うことによって作製されるが、樹脂粒子のような有機基材粒子へ無電解めっきを適用する場合、形成しためっき膜と有機基材粒子との間に強い化学結合が形成され難いため、めっき膜の密着性が充分に得られないという問題があった。従って、めっき膜の密着性の改善が強く求められていた。
The connection reliability of the conductive fine particles used for the anisotropic conductive material and the connecting material for mounting greatly depends on the adhesion of the conductive fine particles to the conductive layer. When conductive fine particles having low adhesion of the conductive layer are connected between circuit boards and electrode terminals facing each other, the conductive layer is easily cracked by stress derived from pressure and heat necessary for connection. As a result, poor continuity and disconnection between the connection terminals are likely to occur.
However, the conductive fine particles are usually produced by electroless plating on the surface of the substrate particles or by performing electroplating after the electroless plating. When plating is applied, it is difficult to form a strong chemical bond between the formed plating film and the organic base material particles, and thus there is a problem that sufficient adhesion of the plating film cannot be obtained. Therefore, improvement of the adhesion of the plating film has been strongly demanded.
めっき膜の密着性を改善するためには、基材粒子表面の粗化や極性基を付与するためのエッチング処理が一般的に利用されている。基材粒子表面を粗化することによって、粗化した基材粒子表面とめっき膜との間に「アンカー効果」という物理的な作用が働き、平滑な表面の場合に比べ密着性が向上される。また、基材表面への極性基の付与は、無電解めっき反応に必要な触媒核の吸着に有利であり、結果としてめっき膜の密着性の向上にも寄与する。
しかしながら、通常、エッチング処理は用いる基材の種類によって方法が異なり、条件を最適化させることが容易ではなく、オーバーエッチングやアンダーエッチングが起こりやすい。また、アクリル樹脂等、エッチングされ難い樹脂も少なくない。そのため、エッチング処理を行っても密着性に優れためっき膜を得られないことがあった。
In order to improve the adhesion of the plating film, an etching process for roughening the surface of the base particle or imparting a polar group is generally used. By roughening the surface of the base particle, a physical action called “anchor effect” works between the rough surface of the base particle and the plating film, and the adhesion is improved as compared with a smooth surface. . In addition, imparting polar groups to the substrate surface is advantageous for adsorption of catalyst nuclei necessary for the electroless plating reaction, and as a result, contributes to improving the adhesion of the plating film.
However, the etching process usually differs depending on the type of substrate used, and it is not easy to optimize the conditions, and overetching and underetching are likely to occur. In addition, there are many resins that are difficult to etch, such as acrylic resins. For this reason, a plating film having excellent adhesion may not be obtained even when etching is performed.
近年、エッチング処理の問題点を解消するために、例えば、特許文献１には、ＵＶとオゾン水による不導体製品のめっき前処理方法が開示されている。しかしながら、この方法は、処理時間が長くなるという問題があった。特許文献２には、前処理方法として被めっき対象物である有機基材を酸化チタン（ＴｉＯ２）粉末の懸濁液に浸漬しながら紫外線を照射する方法が開示されており、酸化チタンの光触媒作用を利用して基材の表面を改質している。しかしながら、この方法では、表面改質反応は光照射された酸化チタン粒子と基材との接触時にのみ起こり、改質効率と改質の均一性に課題があった。また、酸化チタン微細粉末の懸濁液を利用するので、樹脂粒子に付着した酸化チタン微粒子を完全に除去できず、一部の酸化チタン微粒子が樹脂表面に残留するという問題があった。 In recent years, for example, Patent Literature 1 discloses a pretreatment method for plating a non-conductor product using UV and ozone water in order to solve the problem of the etching process. However, this method has a problem that the processing time becomes long. Patent Document 2 discloses a method of irradiating ultraviolet rays while immersing an organic substrate, which is an object to be plated, in a suspension of titanium oxide (TiO 2 ) powder as a pretreatment method. The surface of the base material is modified using the action. However, in this method, the surface modification reaction occurs only when the titanium oxide particles irradiated with light and the substrate come into contact with each other, and there are problems in modification efficiency and uniformity of modification. Further, since a suspension of fine titanium oxide powder is used, the fine titanium oxide particles adhering to the resin particles cannot be completely removed, and there is a problem that some of the fine titanium oxide particles remain on the resin surface.
本発明は、基材となる樹脂粒子との密着性の高い金属層を形成することができる導電性微粒子の製造方法を提供することを目的とする。また、本発明は、該導電性微粒子の製造方法を用いて製造される導電性微粒子を提供することを目的とする。 An object of this invention is to provide the manufacturing method of the electroconductive fine particles which can form a metal layer with high adhesiveness with the resin particle used as a base material. Moreover, an object of this invention is to provide the electroconductive fine particles manufactured using this manufacturing method of electroconductive fine particles.
本発明は、樹脂粒子と酸化物微粒子との混合物を０．５〜１００ＭＰａの範囲内で加圧することにより、上記樹脂粒子の表面に上記酸化物微粒子を圧着する工程１と、上記樹脂粒子の表面から酸化物微粒子を除去し、表面に複数の凹部を有する樹脂粒子を得る工程２と、上記表面に複数の凹部を有する樹脂粒子の表面に金属層を形成する工程３とを有し、上記凹部は、開口の平均直径が０．０１〜１．０μｍであり、かつ、上記樹脂粒子表面における上記凹部の面積占有率が２０〜８０％である導電性微粒子の製造方法である。
以下に本発明を詳述する。
The present invention includes a step 1 of pressing the oxide fine particles onto the surface of the resin particles by pressurizing a mixture of resin particles and oxide fine particles within a range of 0.5 to 100 MPa, and the surface of the resin particles. And removing the oxide fine particles from the surface to obtain resin particles having a plurality of recesses on the surface, and forming a metal layer on the surface of the resin particles having a plurality of recesses on the surface. Is a method for producing conductive fine particles having an average diameter of openings of 0.01 to 1.0 μm and an area occupancy ratio of the recesses on the surface of the resin particles of 20 to 80%.
The present invention is described in detail below.
本発明者は、基材となる樹脂粒子の表面に酸化物微粒子を圧着した後、該酸化物微粒子を除去することで該樹脂粒子の表面に凹部を形成することにより、該樹脂粒子の表面に金属層を強く密着させることができることを見出し、本発明を完成させるに至った。 The present inventor forms a concave portion on the surface of the resin particle by pressing the oxide fine particle on the surface of the resin particle serving as a base material and then removing the oxide fine particle, thereby forming a surface on the resin particle surface. It has been found that the metal layer can be strongly adhered, and the present invention has been completed.
本発明の導電性微粒子の製造方法では、まず、樹脂粒子と酸化物微粒子との混合物を０．５〜１００ＭＰａの範囲内で加圧することにより、上記樹脂粒子の表面に上記酸化物微粒子を圧着する工程１を行う。上記工程１では、０．５〜１００ＭＰａの範囲内の加圧によって樹脂粒子が膨潤し、膨潤した樹脂粒子に酸化物微粒子が入り込み、常圧に戻すことで酸化物微粒子が樹脂粒子の表面に固定される。 In the method for producing conductive fine particles of the present invention, first, the oxide fine particles are pressure-bonded to the surface of the resin particles by pressurizing a mixture of resin particles and oxide fine particles within a range of 0.5 to 100 MPa. Step 1 is performed. In step 1, the resin particles are swollen by pressurization within a range of 0.5 to 100 MPa, and the oxide fine particles enter the swollen resin particles, and the oxide fine particles are fixed to the surface of the resin particles by returning to normal pressure. Is done.
上記樹脂粒子を構成する樹脂は特に限定されず、例えば、ポリオレフィン、（メタ）アクリル樹脂、アクリレートとジビニルベンゼンとの共重合樹脂、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、メラニ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、フェニル樹脂等が挙げられる。
上記ポリオレフィンは特に限定されず、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、ポリブタジエン等が挙げられる。
上記（メタ）アクリル樹脂は特に限定されず、ポリメチル（メタ）アクリレート等が挙げられる。
これらの樹脂は単独で用いてもよいし、２種以上を併用してもよい。
The resin constituting the resin particles is not particularly limited. For example, polyolefin, (meth) acrylic resin, copolymer resin of acrylate and divinylbenzene, polyalkylene terephthalate, polysulfone, polycarbonate, polyamide, phenol formaldehyde resin, melanin formaldehyde resin Benzoguanamine formaldehyde resin, urea formaldehyde resin, phenyl resin and the like.
The polyolefin is not particularly limited, and examples thereof include polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polytetrafluoroethylene, polyisobutylene, and polybutadiene.
The (meth) acrylic resin is not particularly limited, and examples thereof include polymethyl (meth) acrylate.
These resins may be used alone or in combination of two or more.
上記樹脂粒子の１０％Ｋ値の好ましい下限は１０００Ｎ／ｍｍ２、好ましい上限は１５０００Ｎ／ｍｍ２である。上記１０％Ｋ値が１０００Ｎ／ｍｍ２未満であると、樹脂粒子を圧縮変形させると、樹脂粒子が破壊されることがある。上記１０％Ｋ値が１５０００Ｎ／ｍｍ２を超えると、得られる導電性微粒子が電極を傷つけることがある。上記１０％Ｋ値のより好ましい下限は２０００Ｎ／ｍｍ２、より好ましい上限は１００００Ｎ／ｍｍ２である。
なお、上記１０％Ｋ値は、微小圧縮試験器（例えば、島津製作所社製、「ＰＣＴ−２００」）を用い、樹脂粒子を直径５０μｍのダイアモンド製円柱の平滑圧子端面で、圧縮速度２．６ｍＮ／秒、最大試験荷重１０ｇの条件下で圧縮した場合の圧縮変位（ｍｍ）を測定し、下記式により求めることができる。
Ｋ値（Ｎ／ｍｍ２）＝（３／√２）・Ｆ・Ｓ−３／２・Ｒ−１／２
Ｆ：樹脂粒子の１０％圧縮変形における荷重値（Ｎ）
Ｓ：樹脂粒子の１０％圧縮変形における圧縮変位（ｍｍ）
Ｒ：樹脂粒子の半径（ｍｍ）
A preferred lower limit of the 10% K value of the resin particles is 1000 N / mm 2, the upper limit is preferably 15000 N / mm 2. If the 10% K value is less than 1000 N / mm 2 , the resin particles may be destroyed when the resin particles are compressed and deformed. When the 10% K value exceeds 15000 N / mm 2 , the resulting conductive fine particles may damage the electrode. A more preferred lower limit of the 10% K value 2000N / mm 2, and more preferable upper limit is 10000 N / mm 2.
The 10% K value is obtained by using a micro-compression tester (for example, “PCT-200” manufactured by Shimadzu Corporation) and using a smooth indenter end face of a diamond cylinder having a diameter of 50 μm and a compression speed of 2.6 mN. The compression displacement (mm) when compressed under the conditions of 10 g / sec and a maximum test load of 10 g can be measured and determined by the following formula.
K value (N / mm 2) = ( 3 / √2) · F · S -3/2 · R -1/2
F: Load value (N) in 10% compression deformation of resin particles
S: Compression displacement (mm) in 10% compression deformation of resin particles
R: radius of resin particles (mm)
上記樹脂粒子の平均粒子径は特に限定されないが、好ましい下限は０．５μｍ、好ましい上限は２０００μｍである。上記樹脂粒子の平均粒子径が０．５μｍ未満であると、上記樹脂粒子が凝集しやすくなり、凝集した上記樹脂粒子の表面に金属層を形成した導電性微粒子は、隣接する電極間を短絡させることがある。上記樹脂粒子の平均粒子径が２０００μｍを超えると、異方性導電材料として回路基板等に用いられる範囲を超えることがある。上記樹脂粒子の平均粒子径のより好ましい下限は１μｍ、より好ましい上限は１０００μｍである。
なお、本明細書において上記平均粒子径は、光学顕微鏡又は電子顕微鏡を用いて無作為に選んだ５０個の粒子の粒子径を測定し、測定した粒子径を算術平均することにより求められたものである。
The average particle diameter of the resin particles is not particularly limited, but a preferable lower limit is 0.5 μm and a preferable upper limit is 2000 μm. When the average particle diameter of the resin particles is less than 0.5 μm, the resin particles are likely to aggregate, and the conductive fine particles in which a metal layer is formed on the surface of the aggregated resin particles short-circuit between adjacent electrodes. Sometimes. When the average particle diameter of the resin particles exceeds 2000 μm, it may exceed the range used for a circuit board or the like as an anisotropic conductive material. The more preferable lower limit of the average particle diameter of the resin particles is 1 μm, and the more preferable upper limit is 1000 μm.
In the present specification, the average particle diameter is obtained by measuring the particle diameters of 50 particles randomly selected using an optical microscope or an electron microscope and arithmetically averaging the measured particle diameters. It is.
上記樹脂粒子の平均粒子径の変動係数は特に限定されないが、１０％以下であることが好ましい。上記変動係数が１０％を超えると、得られる導電性微粒子の接続信頼性が低下することがある。
なお、上記変動係数とは、粒子径分布から得られる標準偏差を平均粒子径で除して得られる値を百分率（％）で示した数値である。
The coefficient of variation of the average particle diameter of the resin particles is not particularly limited, but is preferably 10% or less. If the coefficient of variation exceeds 10%, the connection reliability of the obtained conductive fine particles may be lowered.
The coefficient of variation is a numerical value obtained by dividing the standard deviation obtained from the particle size distribution by the average particle size and expressed as a percentage (%).
上記樹脂粒子を製造する方法は特に限定されず、例えば、乳化重合、懸濁重合、シード重合、分散重合、分散シード重合等の重合法による方法が挙げられる。上記重合の際に高分子保護剤や界面活性剤等の添加剤を添加してもよい。 The method for producing the resin particles is not particularly limited, and examples thereof include a method using a polymerization method such as emulsion polymerization, suspension polymerization, seed polymerization, dispersion polymerization, or dispersion seed polymerization. During the polymerization, additives such as a polymer protective agent and a surfactant may be added.
本発明の導電性微粒子の製造方法では、上記酸化物微粒子によって上記樹脂粒子の表面に凹部を形成する。
上記酸化物微粒子を構成する酸化物は特に限定されないが、酸化マグネシウム、酸化アルミニウム、酸化マンガン、酸化バナジウム、酸化スズ、酸化鉄、酸化コバルト、酸化銀、酸化ニッケル、酸化銅、酸化亜鉛からなる群から選ばれる少なくとも１種であることが好ましい。
In the method for producing conductive fine particles of the present invention, recesses are formed on the surface of the resin particles by the oxide fine particles.
The oxide constituting the oxide fine particles is not particularly limited, but includes a group consisting of magnesium oxide, aluminum oxide, manganese oxide, vanadium oxide, tin oxide, iron oxide, cobalt oxide, silver oxide, nickel oxide, copper oxide, and zinc oxide. It is preferably at least one selected from
上記酸化物微粒子の平均粒子径は特に限定されないが、好ましい上限は上記樹脂粒子の平均粒子径の１／１０である。上記酸化物微粒子の平均粒子径が上記樹脂粒子の平均粒子径の１／１０を超えると、上記酸化物微粒子を上記樹脂粒子の表面に圧着することができなくなることがある。上記酸化物微粒子の平均粒子径のより好ましい上限は上記樹脂粒子の平均粒子径の１／５０である。 The average particle diameter of the oxide fine particles is not particularly limited, but a preferable upper limit is 1/10 of the average particle diameter of the resin particles. When the average particle diameter of the oxide fine particles exceeds 1/10 of the average particle diameter of the resin particles, the oxide fine particles may not be able to be pressure bonded to the surface of the resin particles. A more preferable upper limit of the average particle diameter of the oxide fine particles is 1/50 of the average particle diameter of the resin particles.
上記工程１において、上記樹脂粒子と上記酸化物微粒子とは、媒体に分散させることが好ましい。上記媒体に分散させることにより、上記樹脂粒子と上記酸化物微粒子とが均一に混ざり合い、高い効率で上記酸化物微粒子を上記樹脂粒子の表面に圧着することができる。 In the step 1, the resin particles and the oxide fine particles are preferably dispersed in a medium. By dispersing in the medium, the resin particles and the oxide fine particles are uniformly mixed, and the oxide fine particles can be pressure-bonded to the surface of the resin particles with high efficiency.
上記媒体としては、常温常圧で上記樹脂粒子に対して貧溶媒である液状媒体及び／又は常温常圧で気体である加圧流体が好適である。液状の媒体を用いれば上記樹脂粒子を分散させることが極めて容易となり、また、常温常圧で上記樹脂粒子に対して貧溶媒であれば、上記樹脂粒子を変形させたり変質させたりすることもない。一方、常温常圧で気体である加圧流体を用いれば、得られる表面に酸化物微粒子が圧着した樹脂粒子を媒体から単離したり乾燥させたりする必要がない。
上記常温常圧で上記樹脂粒子に対して貧溶媒である液状媒体は特に限定されず、樹脂粒子を構成する樹脂に応じて適宜選択すればよいが、例えば、水や、アルコール等の有機溶剤等が挙げられる。
上記常温常圧で気体である加圧流体は特に限定されないが、二酸化炭素、窒素、酸素、空気、水素、アルゴン、ヘリウム、ネオンからなる群より選択される少なくとも１種であることが好適である。
これらの媒体のなかでも、超臨界状態又は亜臨界状態の二酸化炭素が特に好適である。
上記超臨界状態又は亜臨界状態の二酸化炭素は、上記樹脂粒子に対して高い親和性を示す。樹脂粒子の良溶媒も上記超臨界状態又は亜臨界状態の二酸化炭素と同様に高い親和性を示すが、上記良溶媒は密度が高いことから、上記樹脂粒子を完全に溶解してしまったり、上記樹脂粒子の凝集や合一を促進したりすることがある。一方、上記超臨界状態又は亜臨界状態の二酸化炭素は上記樹脂粒子に対する親和性は高いものの、上記樹脂粒子を溶解するほどには密度が高くないことから、上記樹脂粒子を溶解することなく、上記樹脂粒子の表面近傍に浸透し、上記樹脂粒子の表面近傍を適度に膨潤させることができる。上記樹脂粒子の表面近傍を膨潤させることにより、上記酸化物微粒子が膨潤した樹脂粒子の表面近傍に入り込む。その後常温常圧に戻し、二酸化炭素を気体の状態にすることにより、上記酸化物微粒子が上記樹脂粒子の表面に打ち込まれたように固定された樹脂粒子が得られる。
The medium is preferably a liquid medium that is a poor solvent for the resin particles at normal temperature and pressure and / or a pressurized fluid that is gas at normal temperature and pressure. If a liquid medium is used, it is very easy to disperse the resin particles, and if the solvent is a poor solvent for the resin particles at normal temperature and pressure, the resin particles will not be deformed or altered. . On the other hand, if a pressurized fluid that is a gas at normal temperature and pressure is used, there is no need to isolate or dry the resin particles having oxide fine particles pressed onto the surface obtained from the medium.
The liquid medium which is a poor solvent for the resin particles at the normal temperature and normal pressure is not particularly limited, and may be appropriately selected according to the resin constituting the resin particles. For example, water, an organic solvent such as alcohol, etc. Is mentioned.
The pressurized fluid that is a gas at normal temperature and pressure is not particularly limited, but is preferably at least one selected from the group consisting of carbon dioxide, nitrogen, oxygen, air, hydrogen, argon, helium, and neon. .
Among these media, carbon dioxide in a supercritical state or a subcritical state is particularly preferable.
Carbon dioxide in the supercritical state or subcritical state shows high affinity for the resin particles. The good solvent of the resin particles also shows a high affinity like the carbon dioxide in the supercritical state or subcritical state, but since the good solvent has a high density, the resin particles may be completely dissolved, It may promote aggregation and coalescence of resin particles. On the other hand, carbon dioxide in the supercritical state or subcritical state has a high affinity for the resin particles, but the density is not so high as to dissolve the resin particles. It penetrates into the vicinity of the surface of the resin particles, and the vicinity of the surface of the resin particles can be appropriately swollen. By swelling the vicinity of the surface of the resin particles, the oxide fine particles enter the vicinity of the surface of the swollen resin particles. Thereafter, the temperature is returned to room temperature and normal pressure, and carbon dioxide is changed to a gaseous state, thereby obtaining resin particles fixed as if the oxide fine particles were driven into the surface of the resin particles.
上記媒体を用いる場合、上記酸化物微粒子は、上記媒体中に直接分散させてもよいし、適当な分散媒に分散させた分散液を上記媒体中に分散させてもよい。
また、上記酸化物微粒子の上記媒体中での分散性を向上させるために、上記媒体中に分散安定剤を添加することが好ましい。上記分散安定剤としては、上記媒体と親和性の高い官能基を有する化合物が好適である。上記媒体が超臨界状態又は亜臨界状態の二酸化炭素である場合、上記親和性の高い官能基としては、例えば、カルボニル官能基、ケイ素含有官能基、ハロゲン化された原子団を有する官能基、炭素数が９以下の直鎖アルキル基等が挙げられる。
上記カルボニル官能基は特に限定されず、例えば、エステル基、カルボキシル基、カルボニル基、アミド基等が挙げられる。
上記ケイ素含有官能基は特に限定されず、例えば、シラノール基等が挙げられる。
上記ハロゲン化された原子団を有する官能基は特に限定されず、例えば、パーフルオロアルキル基等のフッ素含有官能基等が挙げられる。
上記分散安定剤は、単独で用いてもよいし、２種以上を併用してもよい。
When the medium is used, the oxide fine particles may be directly dispersed in the medium, or a dispersion liquid dispersed in an appropriate dispersion medium may be dispersed in the medium.
In order to improve the dispersibility of the oxide fine particles in the medium, it is preferable to add a dispersion stabilizer to the medium. As the dispersion stabilizer, a compound having a functional group having high affinity with the medium is suitable. When the medium is carbon dioxide in a supercritical state or subcritical state, examples of the functional group having high affinity include a carbonyl functional group, a silicon-containing functional group, a functional group having a halogenated atomic group, and carbon. Examples thereof include straight chain alkyl groups having a number of 9 or less.
The carbonyl functional group is not particularly limited, and examples thereof include an ester group, a carboxyl group, a carbonyl group, and an amide group.
The silicon-containing functional group is not particularly limited, and examples thereof include a silanol group.
The functional group having a halogenated atomic group is not particularly limited, and examples thereof include a fluorine-containing functional group such as a perfluoroalkyl group.
The said dispersion stabilizer may be used independently and may use 2 or more types together.
上記工程１において、上記樹脂粒子と上記酸化物微粒子との混合物に加える圧力の下限は０．５ＭＰａ、上限は１００ＭＰａである。上記圧力が０．５ＭＰａ未満であると、上記樹脂粒子の表面を充分に膨潤させることができなかったり、運動エネルギーが不足したりして上記酸化物微粒子の圧着が不充分となり、充分な大きさの凹部を形成できなくなる。上記圧力が１００ＭＰａを超えると、上記樹脂粒子が溶解したり、凝集したりする。上記圧力の好ましい上限は５０ＭＰａである。上記工程１における加圧状態は、超臨界状態又は亜臨界状態であることが好ましく、上記媒体として二酸化炭素を用いる場合、この圧力範囲では常に超臨界状態又は亜臨界状態となる。
また、上記工程１において上記媒体を用いる場合、上記樹脂粒子と上記酸化物微粒子と上記媒体とを混合してから加圧してもよいし、上記樹脂粒子と上記酸化物微粒子との混合物に予め加圧した上記媒体を加えてもよい。
In the step 1, the lower limit of the pressure applied to the mixture of the resin particles and the oxide fine particles is 0.5 MPa, and the upper limit is 100 MPa. When the pressure is less than 0.5 MPa, the surface of the resin particles cannot be sufficiently swelled, or the kinetic energy is insufficient, so that the oxide fine particles are not sufficiently pressed and are sufficiently large. It becomes impossible to form the recess. When the pressure exceeds 100 MPa, the resin particles are dissolved or aggregated. A preferable upper limit of the pressure is 50 MPa. The pressurized state in Step 1 is preferably a supercritical state or a subcritical state. When carbon dioxide is used as the medium, the pressure state is always a supercritical state or a subcritical state.
Further, when the medium is used in the step 1, the resin particles, the oxide fine particles, and the medium may be mixed and then pressurized, or may be added in advance to the mixture of the resin particles and the oxide fine particles. The pressed medium may be added.
上記工程１において、加圧する際の温度は特に限定されないが、好ましい上限は上記樹脂粒子を構成する樹脂のガラス転移温度よりも５℃低い温度である。上記加圧する際の温度が上記樹脂粒子を構成する樹脂のガラス転移温度よりも５℃低い温度を超えると、上記樹脂粒子の表面が溶解して凝集することがある。上記加圧する際の温度のより好ましい上限は上記樹脂粒子を構成する樹脂のガラス転移温度よりも１０℃低い温度である。
また、上記樹脂粒子を構成する樹脂が結晶性樹脂である場合には、上記加圧する際の温度の好ましい上限は樹脂粒子を構成する樹脂の融点よりも５℃低い温度であり、より好ましい上限は樹脂粒子を構成する樹脂の融点よりも１０℃低い温度である。
In the step 1, the temperature at the time of pressurization is not particularly limited, but a preferable upper limit is a temperature 5 ° C. lower than the glass transition temperature of the resin constituting the resin particles. When the temperature at the time of pressurization exceeds 5 ° C. lower than the glass transition temperature of the resin constituting the resin particles, the surface of the resin particles may be dissolved and aggregated. A more preferable upper limit of the temperature at the time of pressurization is a temperature that is 10 ° C. lower than the glass transition temperature of the resin constituting the resin particles.
Further, when the resin constituting the resin particles is a crystalline resin, the preferred upper limit of the temperature at the time of pressurization is a temperature 5 ° C. lower than the melting point of the resin constituting the resin particles, and the more preferred upper limit is The temperature is 10 ° C. lower than the melting point of the resin constituting the resin particles.
上記樹脂粒子と上記酸化物微粒子との混合物を加圧した後、常温常圧に戻すことにより、樹脂粒子を変質させたり変形させたりすることなく、上記酸化物微粒子が表面に圧着した樹脂粒子を得ることができる。常温常圧に戻した後に、必要に応じてろ過及び洗浄処理を行ってもよい。 After pressurizing the mixture of the resin particles and the oxide fine particles, the resin particles having the oxide fine particles pressed onto the surface without changing or deforming the resin particles by returning to normal temperature and normal pressure Obtainable. After returning to normal temperature and pressure, filtration and washing may be performed as necessary.
本発明の導電性微粒子の製造方法では、次に、上記工程１で得られた酸化物微粒子が表面に圧着した樹脂粒子の表面から酸化物微粒子を除去し、表面に複数の凹部を有する樹脂粒子を得る工程２を行う。
上記工程２は、上記工程１で得られた酸化物微粒子が表面に圧着した樹脂粒子を、酸、アルカリ、又は、金属イオンと錯体を形成できる錯化剤の水溶液に浸漬することにより行われることが好ましい。
In the method for producing conductive fine particles of the present invention, next, the oxide fine particles obtained in step 1 above are removed from the surface of the resin particles press-bonded to the surface, and the resin particles having a plurality of recesses on the surface Step 2 is obtained.
Step 2 is performed by immersing the resin particles obtained by pressure-bonding the oxide fine particles obtained in Step 1 above in an aqueous solution of a complexing agent capable of forming a complex with an acid, alkali, or metal ion. Is preferred.
上記酸は特に限定されず、例えば、塩酸、硝酸、硫酸、又は、これらの混合物等が挙げられる。
上記アルカリは特に限定されず、例えば、水酸化ナトリウム、水酸化カリウム、水酸化リチウム等が挙げられる。
上記錯化剤は特に限定されず、上記酸化物微粒子の中の金属部分と錯体を形成できるものであれば適用可能である。例えば、エタノールアミン、エチレンジアミン、エチレンジアミン四酢酸等のアミン系錯化剤、クエン酸、リンゴ酸、酒石酸等のカルボン酸系錯化剤、１１−メルカプトウンデカン酸等のチオカルボン酸系錯化剤等が挙げられる。
The acid is not particularly limited, and examples thereof include hydrochloric acid, nitric acid, sulfuric acid, or a mixture thereof.
The alkali is not particularly limited, and examples thereof include sodium hydroxide, potassium hydroxide, lithium hydroxide and the like.
The complexing agent is not particularly limited, and any complexing agent can be used as long as it can form a complex with the metal portion in the oxide fine particles. For example, amine complexing agents such as ethanolamine, ethylenediamine and ethylenediaminetetraacetic acid, carboxylic acid complexing agents such as citric acid, malic acid and tartaric acid, thiocarboxylic acid complexing agents such as 11-mercaptoundecanoic acid, etc. It is done.
上記凹部開口の平均直径の下限は０．０１μｍ、上限は１．０μｍである。上記凹部開口の平均直径がこの範囲外であると、得られる導電性微粒子が金属層の密着性に劣るものとなる。
また、上記凹部の深さは特に限定されないが、上記凹部開口の平均直径以下であることが好ましい。
The lower limit of the average diameter of the recess openings is 0.01 μm, and the upper limit is 1.0 μm. When the average diameter of the recess openings is outside this range, the obtained conductive fine particles are inferior in the adhesion of the metal layer.
Moreover, the depth of the said recessed part is although it does not specifically limit, It is preferable that it is below the average diameter of the said recessed part opening.
上記樹脂粒子表面における上記凹部の面積占有率の下限は２０％、上限は８０％である。上記凹部の面積占有率がこの範囲外であると、得られる導電性微粒子が金属層の密着性に劣るものとなる。上記凹部の面積占有率の好ましい下限は３０％、好ましい上限は７０％である。
なお、本明細書において上記凹部の面積占有率とは、得られた表面に複数の凹部を有する樹脂粒子１００個について、それぞれの電子顕微鏡写真を画像処理することにより算出される、樹脂粒子の全表面積における凹部の占める割合の平均値をいう。
The lower limit of the area occupation ratio of the recesses on the surface of the resin particles is 20%, and the upper limit is 80%. When the area occupation ratio of the recesses is outside this range, the obtained conductive fine particles are inferior in the adhesion of the metal layer. The preferable lower limit of the area occupancy ratio of the recesses is 30%, and the preferable upper limit is 70%.
In the present specification, the area occupancy ratio of the recesses is calculated by image processing of each electron micrograph for 100 resin particles having a plurality of recesses on the obtained surface. It means the average value of the proportion of the recesses in the surface area.
本発明の導電性微粒子の製造方法では、次に、上記工程２で得られた表面に複数の凹部を有する樹脂粒子の表面に金属層を形成する工程３を行う。 In the method for producing conductive fine particles of the present invention, next, Step 3 is performed in which a metal layer is formed on the surface of the resin particles having a plurality of recesses on the surface obtained in Step 2 above.
上記工程３において、上記表面に複数の凹部を有する樹脂粒子の表面に金属層を形成する方法としては、無電解めっき又は電解めっきが好適であり、無電解めっきのみ、又は、無電解めっきを行った後に電解めっきを行うことがより好適である。
上記無電解めっき過程としては、酸化物微粒子を除去し、表面に複数の凹部を形成された樹脂粒子に界面活性剤を吸着する工程、触媒化工程及び無電解めっき工程の順で行うことが好ましい。
In the step 3, as a method of forming a metal layer on the surface of the resin particles having a plurality of recesses on the surface, electroless plating or electrolytic plating is suitable, and only electroless plating or electroless plating is performed. More preferably, the electroplating is performed after.
The electroless plating process is preferably performed in the order of removing the oxide fine particles and adsorbing the surfactant to the resin particles having a plurality of recesses formed on the surface, the catalyzing process, and the electroless plating process. .
上記触媒化工程は、基材となる上記表面に複数の凹部を有する樹脂粒子の表面に無電解めっきの起点となる触媒を付与する工程である。上記触媒化工程では、例えば、センシタイジング工程と、アクチベイジング工程とが行われる。上記センシタイジング工程として、ラウリル硫酸ナトリウム等の界面活性剤を吸着させた上記表面に複数の凹部を有する樹脂粒子を二塩化錫溶液中で攪拌することにより、上記表面に複数の凹部を有する樹脂粒子の表面にＳｎ２＋イオンが吸着される。上記アクチベイジング工程として、Ｓｎ２＋イオンが吸着した樹脂粒子を、二塩化パラジウム溶液中で攪拌することにより、樹脂粒子の表面にパラジウム触媒が付与される。なお、上記アクチベイジング工程では、樹脂粒子の表面で、Ｓｎ２＋＋Ｐｄ２＋→Ｓｎ４＋＋Ｐｄ０で示される反応が行われる。 The catalyzing step is a step of imparting a catalyst serving as a starting point of electroless plating to the surface of the resin particles having a plurality of recesses on the surface serving as a base material. In the catalyzing step, for example, a sensitizing step and an activating step are performed. Resin having a plurality of recesses on the surface by stirring resin particles having a plurality of recesses on the surface adsorbed with a surfactant such as sodium lauryl sulfate in the tin dichloride solution as the sensitizing step Sn 2+ ions are adsorbed on the surface of the particles. As the above-mentioned activating process, the resin particles adsorbed with Sn 2+ ions are stirred in a palladium dichloride solution, whereby a palladium catalyst is imparted to the surfaces of the resin particles. In the activating process, a reaction represented by Sn 2+ + Pd 2+ → Sn 4+ + Pd 0 is performed on the surface of the resin particles.
上記無電解めっき工程は、パラジウム触媒が付与された上記樹脂粒子を還元剤の存在下で、無電解めっき浴中に浸漬し、付与されたパラジウム触媒を起点として上記樹脂粒子の表面にめっき金属を析出させ、金属層を形成する工程である。 In the electroless plating step, the resin particles provided with a palladium catalyst are immersed in an electroless plating bath in the presence of a reducing agent, and the plating metal is applied to the surface of the resin particles using the applied palladium catalyst as a starting point. It is the process of forming and forming a metal layer.
上記金属層を構成する金属は特に限定されず、例えば、ニッケル、金、銀、銅、白金、亜鉛、鉄、錫、鉛、アルミニウム、コバルト、インジウム、クロム、チタン、アンチモン、ビスマス、ゲルマニウム、又は、これらの合金等が挙げられる。 The metal constituting the metal layer is not particularly limited. For example, nickel, gold, silver, copper, platinum, zinc, iron, tin, lead, aluminum, cobalt, indium, chromium, titanium, antimony, bismuth, germanium, or And alloys thereof.
上記金属層全体の厚さは特に限定されないが、好ましい下限は０．０１μｍ、好ましい上限は１００μｍである。上記金属層全体の厚さが０．０１μｍ未満であると、上記金属層が割れやすくなったり、導電微粒子として充分に機能を発揮できなくなったりすることがある。上記金属層全体の厚さが１００μｍを超えると、得られる導電性微粒子の柔軟性が損なわれたり、得られる導電性微粒子が凝集しやすくなり、隣接する電極間の短絡を引き起こしたりすることがある。上記金属層全体の厚さのより好ましい下限は０．０２μｍ、より好ましい上限は８０μｍである。
なお、上記金属層全体の厚さは、無作為に選んだ１０個の導電性微粒子の断面を走査型電子顕微鏡（ＳＥＭ）により観察して厚さを測定し、測定値を算術平均した厚さである。
Although the thickness of the said whole metal layer is not specifically limited, A preferable minimum is 0.01 micrometer and a preferable upper limit is 100 micrometers. If the total thickness of the metal layer is less than 0.01 μm, the metal layer may be easily broken or may not function sufficiently as conductive fine particles. When the total thickness of the metal layer exceeds 100 μm, the flexibility of the obtained conductive fine particles may be impaired, or the obtained conductive fine particles may easily aggregate, causing a short circuit between adjacent electrodes. . A more preferable lower limit of the thickness of the entire metal layer is 0.02 μm, and a more preferable upper limit is 80 μm.
The thickness of the entire metal layer is a thickness obtained by observing a cross section of 10 randomly selected conductive fine particles with a scanning electron microscope (SEM) and measuring the measured value arithmetically. It is.
本発明の導電性微粒子の製造方法を用いて製造される導電性微粒子もまた、本発明の１つである。 The conductive fine particles produced using the method for producing conductive fine particles of the present invention are also one aspect of the present invention.
本発明によれば、基材となる樹脂粒子との密着性の高い金属層を形成することができる導電性微粒子の製造方法を提供することができる。また、本発明によれば、該導電性微粒子の製造方法を用いて製造される導電性微粒子を提供することができる。 ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the electroconductive fine particles which can form a metal layer with high adhesiveness with the resin particle used as a base material can be provided. Moreover, according to this invention, the electroconductive fine particles manufactured using the manufacturing method of this electroconductive fine particle can be provided.
以下に実施例を掲げて本発明を更に詳しく説明するが、本発明はこれら実施例のみに限定されない。 Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.
（実施例１）
（１）表面に凹部を有する樹脂粒子の作製
ジビニルベンゼンとテトラメチロールメタンテトラアクリレートとを重量比１：１で共重合させた樹脂粒子（平均粒子径１９０μｍ）１ｇと、２重量％の酸化アルミニウム微粒子（平均粒子径０．５μｍ）水分散液２０ｇの混合液を耐圧反応装置の反応器内に導入した。攪拌羽で混合液を攪拌しながら、２００℃に昇温した。次に、二酸化炭素ガスを反応器内に導入し、反応器内の圧力を２０ＭＰａに調整し、２００℃、２０ＭＰａのまま１時間保持した。次いで、反応器を室温近くまで冷却し、混合液を取り出した。得られた混合液をろ過し、洗浄し、乾燥させることにより、表面に酸化アルミニウム微粒子が圧着した樹脂粒子を得た。
得られた表面に酸化アルミニウム微粒子が圧着した樹脂粒子の表面及び断面を、エネルギー分散型Ｘ線検出器が備え付けられた走査型電子顕微鏡を用いて観察した。その結果、樹脂粒子の表面の全面に均一に、複数の酸化アルミニウム微粒子が埋まるように付着しており、酸化アルミニウム微粒子の粒子径の半分以上が樹脂粒子に埋め込まれていることを確認した。
次に、得られた表面に酸化アルミニウム微粒子が圧着した樹脂粒子を０．５ｍｏｌ／Ｌの塩酸に浸漬させ、樹脂粒子表面の酸化アルミニウム微粒子を溶解除去した。酸化アルミニウム微粒子が除去されたことにより、酸化アルミニウム微粒子が埋め込まれていた部分が凹部となり、表面に複数の凹部を有する樹脂粒子が得られた。形成された凹部の深さは凹部開口の直径以下であり、凹部の面積占有率は約５０％であった。
Example 1
(1) Production of resin particles having recesses on the surface 1 g of resin particles (average particle diameter 190 μm) obtained by copolymerizing divinylbenzene and tetramethylolmethanetetraacrylate at a weight ratio of 1: 1, and 2% by weight of aluminum oxide fine particles A mixture of 20 g of an aqueous dispersion (average particle size 0.5 μm) was introduced into a reactor of a pressure resistant reactor. While stirring the mixed solution with a stirring blade, the temperature was raised to 200 ° C. Next, carbon dioxide gas was introduced into the reactor, the pressure in the reactor was adjusted to 20 MPa, and the temperature was maintained at 200 ° C. and 20 MPa for 1 hour. Next, the reactor was cooled to near room temperature, and the mixed solution was taken out. The obtained mixed liquid was filtered, washed, and dried to obtain resin particles having aluminum oxide fine particles pressed onto the surface.
The surface and the cross section of the resin particles in which the aluminum oxide fine particles were pressure-bonded to the obtained surface were observed using a scanning electron microscope equipped with an energy dispersive X-ray detector. As a result, it was confirmed that a plurality of aluminum oxide fine particles were uniformly attached to the entire surface of the resin particles so that more than half of the particle diameter of the aluminum oxide fine particles was embedded in the resin particles.
Next, resin particles having aluminum oxide fine particles pressed onto the obtained surface were immersed in 0.5 mol / L hydrochloric acid to dissolve and remove the aluminum oxide fine particles on the surface of the resin particles. By removing the aluminum oxide fine particles, the portion where the aluminum oxide fine particles were embedded became concave portions, and resin particles having a plurality of concave portions on the surface were obtained. The depth of the formed recess was less than the diameter of the recess opening, and the area occupation ratio of the recess was about 50%.
（２）導電性微粒子の作製
得られた表面に複数の凹部を有する樹脂粒子を０．１重量％のラウリル硫酸ナトリウムを含有する水溶液に５分間浸漬し、樹脂粒子の表面に界面活性剤を吸着させた。得られた界面活性剤を吸着した樹脂粒子を、塩化錫（ＳｎＣｌ２）を２重量％含有する塩酸（塩化水素濃度１０重量％）中で攪拌し、樹脂粒子の表面にＳｎ２＋イオンを吸着させた。次いで、ろ過、洗浄を行い、得られたＳｎ２＋イオンを吸着した樹脂粒子を、０．０１重量％の塩化パラジウム（ＰｄＣｌ２）水溶液中において、５０℃で１０分間攪拌し、樹脂粒子の表面にパラジウムを付与した。得られた表面にパラジウムを付与した樹脂粒子を無電解ニッケルめっき液に分散させ、攪拌することにより、樹脂粒子の表面に厚さ０．５μｍのニッケル層を形成した。更に、電解めっきにより、得られたニッケル層上に厚さ５μｍの銅層を形成し、導電性微粒子を得た。
(2) Production of conductive fine particles Resin particles having a plurality of recesses on the obtained surface are immersed in an aqueous solution containing 0.1 wt% sodium lauryl sulfate for 5 minutes to adsorb the surfactant on the surface of the resin particles. I let you. The obtained resin particles adsorbed with the surfactant are stirred in hydrochloric acid (hydrogen chloride concentration: 10% by weight) containing 2% by weight of tin chloride (SnCl 2 ) to adsorb Sn 2+ ions on the surface of the resin particles. It was. Next, filtration and washing were performed, and the obtained resin particles adsorbed with Sn 2+ ions were stirred in a 0.01 wt% palladium chloride (PdCl 2 ) aqueous solution at 50 ° C. for 10 minutes to form resin particles on the surface. Palladium was applied. The obtained resin particles provided with palladium were dispersed in an electroless nickel plating solution and stirred to form a nickel layer having a thickness of 0.5 μm on the surface of the resin particles. Furthermore, a copper layer having a thickness of 5 μm was formed on the obtained nickel layer by electrolytic plating to obtain conductive fine particles.
（実施例２）
用いた酸化アルミニウム微粒子水分散液中の酸化アルミニウム微粒子の濃度を１０重量％に変更したこと以外は実施例１と同様にして表面に酸化アルミニウム微粒子が圧着した樹脂粒子を作製した。得られた表面に酸化アルミニウム微粒子が圧着した樹脂粒子の表面及び断面を、実施例１と同様にして観察した結果、樹脂粒子の表面の全面に均一に、複数の酸化アルミニウム微粒子が埋まるように付着しており、酸化アルミニウム微粒子の粒子径の半分以上が樹脂粒子に埋め込まれていることを確認した。得られた表面に酸化アルミニウム微粒子が圧着した樹脂粒子について、０．２ｍｏｌ／Ｌの塩酸を用い、実施例１と同様にして表面の酸化アルミニウム微粒子を溶解除去し、表面に複数の凹部を有する樹脂粒子を作製した。形成された凹部の深さは凹部開口の直径以下であり、凹部の面積占有率は約８０％であった。更に、実施例１と同様にして樹脂粒子の表面にニッケル層、及び、得られたニッケル層上に銅層を形成して導電性微粒子を得た。
(Example 2)
Resin particles having aluminum oxide fine particles pressed onto the surface were prepared in the same manner as in Example 1 except that the concentration of the aluminum oxide fine particles in the aqueous dispersion of aluminum oxide fine particles used was changed to 10% by weight. As a result of observing the surface and the cross section of the resin particle having the aluminum oxide fine particles press-bonded to the obtained surface in the same manner as in Example 1, the entire surface of the resin particle is uniformly attached so that a plurality of aluminum oxide fine particles are embedded. It was confirmed that more than half of the particle diameter of the aluminum oxide fine particles was embedded in the resin particles. About the resin particle which the aluminum oxide fine particle crimped | bonded to the obtained surface, 0.2 mol / L hydrochloric acid was used, and the surface aluminum oxide fine particle was dissolved and removed like Example 1, and the resin which has a several recessed part on the surface Particles were made. The depth of the formed recess was not more than the diameter of the recess opening, and the area occupation ratio of the recess was about 80%. Further, in the same manner as in Example 1, a nickel layer was formed on the surface of the resin particles, and a copper layer was formed on the obtained nickel layer to obtain conductive fine particles.
（実施例３）
用いた酸化アルミニウム微粒子水分散液中の酸化アルミニウム微粒子の濃度を０．５重量％に変更したこと以外は実施例１と同様にして表面に酸化アルミニウム微粒子が圧着した樹脂粒子を作製した。得られた表面に酸化アルミニウム微粒子が圧着した樹脂粒子の表面及び断面を、実施例１と同様にして観察した結果、樹脂粒子の表面の全面に均一に、複数の酸化アルミニウム微粒子が埋まるように付着しており、酸化アルミニウム微粒子の粒子径の半分以上が樹脂粒子に埋め込まれていることを確認した。得られた表面に酸化アルミニウム微粒子が圧着した樹脂粒子について、０．２ｍｏｌ／Ｌの塩酸を用い、実施例１と同様にして表面の酸化アルミニウム微粒子を溶解除去し、表面に複数の凹部を有する樹脂粒子を作製した。形成された凹部の深さは凹部開口の直径以下であり、凹部の面積占有率は約２０％であった。更に、実施例１と同様にして樹脂粒子の表面にニッケル層、及び、得られたニッケル層上に銅層を形成して導電性微粒子を得た。
(Example 3)
Resin particles having aluminum oxide fine particles pressed onto the surface were prepared in the same manner as in Example 1 except that the concentration of the aluminum oxide fine particles in the aqueous dispersion of aluminum oxide fine particles used was changed to 0.5% by weight. As a result of observing the surface and the cross section of the resin particle having the aluminum oxide fine particles press-bonded to the obtained surface in the same manner as in Example 1, the entire surface of the resin particle is uniformly attached so that a plurality of aluminum oxide fine particles are embedded. It was confirmed that more than half of the particle diameter of the aluminum oxide fine particles was embedded in the resin particles. About the resin particle which the aluminum oxide fine particle crimped | bonded to the obtained surface, 0.2 mol / L hydrochloric acid was used, and the surface aluminum oxide fine particle was dissolved and removed like Example 1, and the resin which has a several recessed part on the surface Particles were made. The depth of the formed recess was not more than the diameter of the recess opening, and the area occupation ratio of the recess was about 20%. Further, in the same manner as in Example 1, a nickel layer was formed on the surface of the resin particles, and a copper layer was formed on the obtained nickel layer to obtain conductive fine particles.
（実施例４）
用いた酸化アルミニウム微粒子水分散液中の酸化アルミニウム微粒子を平均粒子径が０．０１μｍのものに変更し、濃度を５重量％に変更したこと以外は実施例１と同様にして表面に酸化アルミニウム微粒子が圧着した樹脂粒子を作製した。得られた表面に酸化アルミニウム微粒子が圧着した樹脂粒子の表面及び断面を、実施例１と同様にして観察した結果、樹脂粒子の表面の全面に均一に、複数の酸化アルミニウム微粒子が埋まるように付着しており、酸化アルミニウム微粒子の粒子径の半分以上が樹脂粒子に埋め込まれていることを確認した。得られた表面に酸化アルミニウム微粒子が圧着した樹脂粒子について、０．２ｍｏｌ／Ｌの塩酸を用い、実施例１と同様にして表面の酸化アルミニウム微粒子を溶解除去し、表面に複数の凹部を有する樹脂粒子を作製した。形成された凹部の深さは凹部開口の直径以下であり、凹部の面積占有率は約７０％であった。更に、実施例１と同様にして樹脂粒子の表面にニッケル層、及び、得られたニッケル層上に銅層を形成して導電性微粒子を得た。
Example 4
Aluminum oxide fine particles on the surface were the same as in Example 1 except that the aluminum oxide fine particles in the aqueous dispersion of aluminum oxide fine particles used were changed to those having an average particle diameter of 0.01 μm and the concentration was changed to 5% by weight. The resin particle which pressure bonded was produced. As a result of observing the surface and the cross section of the resin particle having the aluminum oxide fine particles press-bonded to the obtained surface in the same manner as in Example 1, the entire surface of the resin particle is uniformly attached so that a plurality of aluminum oxide fine particles are embedded. It was confirmed that more than half of the particle diameter of the aluminum oxide fine particles was embedded in the resin particles. About the resin particle which the aluminum oxide fine particle crimped | bonded to the obtained surface, 0.2 mol / L hydrochloric acid was used, and the surface aluminum oxide fine particle was dissolved and removed like Example 1, and the resin which has a several recessed part on the surface Particles were made. The depth of the formed recess was not more than the diameter of the recess opening, and the area occupation ratio of the recess was about 70%. Further, in the same manner as in Example 1, a nickel layer was formed on the surface of the resin particles, and a copper layer was formed on the obtained nickel layer to obtain conductive fine particles.
（実施例５）
用いた酸化アルミニウム微粒子水分散液中の酸化アルミニウム微粒子を平均粒子径が１μｍのものに変更し、濃度を５重量％に変更したこと以外は実施例１と同様にして表面に酸化アルミニウム微粒子が圧着した樹脂粒子を作製した。得られた表面に酸化アルミニウム微粒子が圧着した樹脂粒子の表面及び断面を、実施例１と同様にして観察した結果、樹脂粒子の表面の全面に均一に、複数の酸化アルミニウム微粒子が埋まるように付着しており、酸化アルミニウム微粒子の粒子径の半分以上が樹脂粒子に埋め込まれていることを確認した。得られた表面に酸化アルミニウム微粒子が圧着した樹脂粒子について、実施例１と同様にして表面の酸化アルミニウム微粒子を溶解除去し、表面に複数の凹部を有する樹脂粒子を作製した。形成された凹部の深さは凹部開口の直径以下であり、凹部の面積占有率は約４０％であった。更に、実施例１と同様にして樹脂粒子の表面にニッケル層、及び、得られたニッケル層上に銅層を形成して導電性微粒子を得た。
(Example 5)
The aluminum oxide fine particles in the aqueous dispersion of aluminum oxide fine particles used were pressure-bonded to the surface in the same manner as in Example 1 except that the average particle size was changed to 1 μm and the concentration was changed to 5% by weight. Resin particles were produced. As a result of observing the surface and the cross section of the resin particle having the aluminum oxide fine particles press-bonded to the obtained surface in the same manner as in Example 1, the entire surface of the resin particle is uniformly attached so that a plurality of aluminum oxide fine particles are embedded. It was confirmed that more than half of the particle diameter of the aluminum oxide fine particles was embedded in the resin particles. The resin particles having aluminum oxide fine particles pressed onto the obtained surface were dissolved and removed in the same manner as in Example 1 to produce resin particles having a plurality of recesses on the surface. The depth of the formed recess was not more than the diameter of the recess opening, and the area occupation ratio of the recess was about 40%. Further, in the same manner as in Example 1, a nickel layer was formed on the surface of the resin particles, and a copper layer was formed on the obtained nickel layer to obtain conductive fine particles.
（比較例１）
ジビニルベンゼンとテトラメチロールメタンテトラアクリレートとを重量比１：１で共重合させた樹脂粒子（平均粒子径１９０μｍ）を、表面に凹部を形成させずにそのまま基材粒子として用い、実施例１と同様にして表面にニッケル層、及び、得られたニッケル層上に銅層を形成して導電性微粒子を得た。
(Comparative Example 1)
Resin particles (average particle diameter of 190 μm) obtained by copolymerization of divinylbenzene and tetramethylolmethane tetraacrylate at a weight ratio of 1: 1 were used as substrate particles without forming recesses on the surface, as in Example 1. Then, a nickel layer was formed on the surface, and a copper layer was formed on the obtained nickel layer to obtain conductive fine particles.
（比較例２）
用いた酸化アルミニウム微粒子水分散液中の酸化アルミニウム微粒子の濃度を０．０５重量％に変更したこと以外は実施例１と同様にして表面に酸化アルミニウム微粒子が圧着した樹脂粒子を作製した。得られた表面に酸化アルミニウム微粒子が圧着した樹脂粒子の表面及び断面を、実施例１と同様にして観察した結果、樹脂粒子の表面の全面に均一に、複数の酸化アルミニウム微粒子が埋まるように付着しており、酸化アルミニウム微粒子の粒子径の半分以上が樹脂粒子に埋め込まれていることを確認した。得られた表面に酸化アルミニウム微粒子が圧着した樹脂粒子について、実施例１と同様にして表面の酸化アルミニウム微粒子を溶解除去し、表面に複数の凹部を有する樹脂粒子を作製した。形成された凹部の深さは凹部開口の直径以下であり、凹部の面積占有率は約１０％であった。更に、実施例１と同様にして樹脂粒子の表面にニッケル層、及び、得られたニッケル層上に銅層を形成して導電性微粒子を得た。
(Comparative Example 2)
Resin particles having aluminum oxide fine particles pressed onto the surface were prepared in the same manner as in Example 1 except that the concentration of the aluminum oxide fine particles in the aqueous dispersion of aluminum oxide fine particles used was changed to 0.05% by weight. As a result of observing the surface and the cross section of the resin particle having the aluminum oxide fine particles press-bonded to the obtained surface in the same manner as in Example 1, the entire surface of the resin particle is uniformly attached so that a plurality of aluminum oxide fine particles are embedded. It was confirmed that more than half of the particle diameter of the aluminum oxide fine particles was embedded in the resin particles. The resin particles having aluminum oxide fine particles pressed onto the obtained surface were dissolved and removed in the same manner as in Example 1 to produce resin particles having a plurality of recesses on the surface. The depth of the formed recess was not more than the diameter of the recess opening, and the area occupation ratio of the recess was about 10%. Further, in the same manner as in Example 1, a nickel layer was formed on the surface of the resin particles, and a copper layer was formed on the obtained nickel layer to obtain conductive fine particles.
（比較例３）
用いた酸化アルミニウム微粒子水分散液中の酸化アルミニウム微粒子の濃度を１５重量％に変更したこと以外は実施例１と同様にして表面に酸化アルミニウム微粒子が圧着した樹脂粒子を作製した。得られた表面に酸化アルミニウム微粒子が圧着した樹脂粒子の表面及び断面を、実施例１と同様にして観察した結果、樹脂粒子の表面の全面に均一に、複数の酸化アルミニウム微粒子が埋まるように付着しており、酸化アルミニウム微粒子の粒子径の半分以上が樹脂粒子に埋め込まれていることを確認した。得られた表面に酸化アルミニウム微粒子が圧着した樹脂粒子について、０．２ｍｏｌ／Ｌの塩酸を用い、実施例１と同様にして表面の酸化アルミニウム微粒子を溶解除去し、表面に複数の凹部を有する樹脂粒子を作製した。形成された凹部の深さは凹部開口の直径以下であり、凹部の面積占有率は約９０％であった。更に、実施例１と同様にして樹脂粒子の表面にニッケル層、及び、得られたニッケル層上に銅層を形成して導電性微粒子を得た。
(Comparative Example 3)
Resin particles having aluminum oxide fine particles pressed onto the surface were prepared in the same manner as in Example 1 except that the concentration of the aluminum oxide fine particles in the aqueous dispersion of aluminum oxide fine particles used was changed to 15% by weight. As a result of observing the surface and the cross section of the resin particle having the aluminum oxide fine particles press-bonded to the obtained surface in the same manner as in Example 1, the entire surface of the resin particle is uniformly attached so that a plurality of aluminum oxide fine particles are embedded. It was confirmed that more than half of the particle diameter of the aluminum oxide fine particles was embedded in the resin particles. About the resin particle which the aluminum oxide fine particle crimped | bonded to the obtained surface, 0.2 mol / L hydrochloric acid was used, and the surface aluminum oxide fine particle was dissolved and removed like Example 1, and the resin which has a several recessed part on the surface Particles were made. The depth of the formed recess was not more than the diameter of the recess opening, and the area occupation ratio of the recess was about 90%. Further, in the same manner as in Example 1, a nickel layer was formed on the surface of the resin particles, and a copper layer was formed on the obtained nickel layer to obtain conductive fine particles.
（比較例４）
用いた酸化アルミニウム微粒子水分散液中の酸化アルミニウム微粒子を平均粒子径が０．００５μｍのものに変更したこと以外は実施例１と同様にして表面に酸化アルミニウム微粒子が圧着した樹脂粒子を作製した。得られた表面に酸化アルミニウム微粒子が圧着した樹脂粒子の表面及び断面を、実施例１と同様にして観察した結果、樹脂粒子の表面の全面に均一に、複数の酸化アルミニウム微粒子が埋まるように付着しており、酸化アルミニウム微粒子の粒子径の半分以上が樹脂粒子に埋め込まれていることを確認した。得られた表面に酸化アルミニウム微粒子が圧着した樹脂粒子について、実施例１と同様にして表面の酸化アルミニウム微粒子を溶解除去し、表面に複数の凹部を有する樹脂粒子を作製した。形成された凹部の深さは凹部開口の直径以下であり、凹部の面積占有率は約５０％であった。更に、実施例１と同様にして樹脂粒子の表面にニッケル層、及び、得られたニッケル層上に銅層を形成して導電性微粒子を得た。
(Comparative Example 4)
Resin particles having aluminum oxide fine particles pressed onto the surfaces were prepared in the same manner as in Example 1 except that the aluminum oxide fine particles in the aluminum oxide fine particle aqueous dispersion used were changed to those having an average particle size of 0.005 μm. As a result of observing the surface and the cross section of the resin particle having the aluminum oxide fine particles press-bonded to the obtained surface in the same manner as in Example 1, the entire surface of the resin particle is uniformly attached so that a plurality of aluminum oxide fine particles are embedded. It was confirmed that more than half of the particle diameter of the aluminum oxide fine particles was embedded in the resin particles. The resin particles having aluminum oxide fine particles pressed onto the obtained surface were dissolved and removed in the same manner as in Example 1 to produce resin particles having a plurality of recesses on the surface. The depth of the formed recess was less than the diameter of the recess opening, and the area occupation ratio of the recess was about 50%. Further, in the same manner as in Example 1, a nickel layer was formed on the surface of the resin particles, and a copper layer was formed on the obtained nickel layer to obtain conductive fine particles.
（比較例５）
用いた酸化アルミニウム微粒子水分散液中の酸化アルミニウム微粒子を平均粒子径が１０μｍのものに変更したこと以外は実施例１と同様にして表面に酸化アルミニウム微粒子が圧着した樹脂粒子を作製した。得られた表面に酸化アルミニウム微粒子が圧着した樹脂粒子の表面及び断面を、実施例１と同様にして観察した結果、樹脂粒子の表面の全面に均一に、複数の酸化アルミニウム微粒子が埋まるように付着しており、酸化アルミニウム微粒子の粒子径の半分以上が樹脂粒子に埋め込まれていることを確認した。得られた表面に酸化アルミニウム微粒子が圧着した樹脂粒子について、実施例１と同様にして表面の酸化アルミニウム微粒子を溶解除去し、表面に複数の凹部を有する樹脂粒子を作製した。形成された凹部の深さは凹部開口の直径以下であり、凹部の面積占有率は約２５％であった。更に、実施例１と同様にして樹脂粒子の表面にニッケル層、及び、得られたニッケル層上に銅層を形成して導電性微粒子を得た。
(Comparative Example 5)
Resin particles having aluminum oxide fine particles pressed onto the surface were produced in the same manner as in Example 1 except that the aluminum oxide fine particles in the aqueous dispersion of aluminum oxide fine particles used were changed to those having an average particle diameter of 10 μm. As a result of observing the surface and the cross section of the resin particle having the aluminum oxide fine particles press-bonded to the obtained surface in the same manner as in Example 1, the entire surface of the resin particle is uniformly attached so that a plurality of aluminum oxide fine particles are embedded. It was confirmed that more than half of the particle diameter of the aluminum oxide fine particles was embedded in the resin particles. The resin particles having aluminum oxide fine particles pressed onto the obtained surface were dissolved and removed in the same manner as in Example 1 to produce resin particles having a plurality of recesses on the surface. The depth of the formed recess was equal to or less than the diameter of the recess opening, and the area occupation ratio of the recess was about 25%. Further, in the same manner as in Example 1, a nickel layer was formed on the surface of the resin particles, and a copper layer was formed on the obtained nickel layer to obtain conductive fine particles.
＜評価＞
実施例及び比較例で得られた導電性微粒子について以下の評価を行った。結果を表１に示した。
<Evaluation>
The following evaluation was performed about the electroconductive fine particles obtained by the Example and the comparative example. The results are shown in Table 1.
（１）金属層の密着性の評価
得られた導電性微粒子０．５ｇと、直径１．０ｍｍのジルコニアボール２０ｇと、エタノール２０ｇとをポリ容器に入れ、ボールミル処理機を用いて、２００ｒｐｍで１０分間回転処理した。その後、ろ過し、乾燥させ、導電性微粒子を取り出した。取り出された導電性微粒子のうち２００個を走査型電子顕微鏡で観察し、金属層の密着性を以下の基準で評価した。
○：金属層にひび割れ又は剥がれを有する導電性微粒子が２００個中０個
△：金属層にひび割れ又は剥がれを有する導電性微粒子が２００個中１〜１０個
×：金属層にひび割れ又は剥がれを有する導電性微粒子が２００個中１１個以上
(1) Evaluation of adhesion of metal layer 0.5 g of the obtained conductive fine particles, 20 g of zirconia balls having a diameter of 1.0 mm, and 20 g of ethanol were placed in a plastic container, and 10 times at 200 rpm using a ball mill processor. Rotated for minutes. Then, it filtered and dried and took out electroconductive fine particles. Of the extracted conductive fine particles, 200 were observed with a scanning electron microscope, and the adhesion of the metal layer was evaluated according to the following criteria.
○: 0 in 200 conductive fine particles having cracks or peeling in the metal layer Δ: 1-10 in 200 conductive particles having cracks or peeling in the metal layer ×: Cracking or peeling in the metal layer 11 or more conductive particles in 200
（２）凹部開口の平均直径の評価
酸化物微粒子を除去した樹脂粒子を走査型電子顕微鏡で観察し、２００個の粒子における凹部開口の直径を測定し、その平均値を求めた。
(2) Evaluation of average diameter of recess openings The resin particles from which oxide fine particles were removed were observed with a scanning electron microscope, and the diameters of the recess openings in 200 particles were measured, and the average value was obtained.
（３）実装時の金属層の割れの評価
得られた導電性微粒子１１２個を、赤外線リフロー装置を用い、はんだペーストを介して電極ランド上に実装した。リフローでは、ピーク温度２００℃で３分間保持した。光学顕微鏡及び走査型電子顕微鏡を用いて、実装後の導電性微粒子を観察し、金属層の割れを以下の基準で評価した。
○：金属層に割れを有する導電性微粒子が１１２個中０個
△：金属層に割れを有する導電性微粒子が１１２個中１〜５個
×：金属層に割れを有する導電性微粒子が１１２個中６個以上
(3) Evaluation of cracking of metal layer at the time of mounting 112 conductive fine particles obtained were mounted on the electrode land through solder paste using an infrared reflow apparatus. In reflow, the peak temperature was maintained at 200 ° C. for 3 minutes. Using an optical microscope and a scanning electron microscope, the conductive fine particles after mounting were observed, and the crack of the metal layer was evaluated according to the following criteria.
◯: 0 of 112 conductive fine particles having cracks in the metal layer Δ: 1 to 5 conductive particles having cracks in the metal layer ×: 112 conductive fine particles having cracks in the metal layer More than 6
本発明によれば、基材となる樹脂粒子との密着性の高い金属層を形成することができる導電性微粒子の製造方法を提供することができる。また、本発明によれば、該導電性微粒子の製造方法を用いて製造される導電性微粒子を提供することができる。 ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the electroconductive fine particles which can form a metal layer with high adhesiveness with the resin particle used as a base material can be provided. Moreover, according to this invention, the electroconductive fine particles manufactured using the manufacturing method of this electroconductive fine particle can be provided.
Claims (6)
前記樹脂粒子の表面から酸化物微粒子を除去し、表面に複数の凹部を有する樹脂粒子を得る工程２と、
前記表面に複数の凹部を有する樹脂粒子の表面に金属層を形成する工程３とを有し、
前記凹部は、開口の平均直径が０．０１〜１．０μｍであり、かつ、前記樹脂粒子表面における前記凹部の面積占有率が２０〜８０％である
ことを特徴とする導電性微粒子の製造方法。 Step 1 for press-bonding the oxide fine particles to the surface of the resin particles by pressurizing a mixture of resin particles and oxide fine particles within a range of 0.5 to 100 MPa;
Step 2 of removing oxide fine particles from the surface of the resin particles to obtain resin particles having a plurality of recesses on the surface;
Forming a metal layer on the surface of the resin particles having a plurality of recesses on the surface, and
The concave portion has an opening having an average diameter of 0.01 to 1.0 μm and an area occupation ratio of the concave portion on the surface of the resin particle of 20 to 80%. .
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| JP2009221276A JP2011070944A (en) | 2009-09-25 | 2009-09-25 | Manufacturing method for conductive particulates, and the conductive particulates |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012111908A (en) * | 2010-11-26 | 2012-06-14 | Nippon Shokubai Co Ltd | Polymer particle, conductive particulate using the same, and anisotropic conductive material |
| JP2018149813A (en) * | 2011-07-13 | 2018-09-27 | ヌボトロニクス、インク． | Method for manufacturing electronic and mechanical structure |
| WO2021206201A1 (en) * | 2020-04-10 | 2021-10-14 | 주식회사 씨앤씨머티리얼즈 | Conductive polymer particles containing nickel metal layer |
| WO2021206202A1 (en) * | 2020-04-10 | 2021-10-14 | 주식회사 씨앤씨머티리얼즈 | Conductive polymer particles containing silver metal layer |
-
2009
- 2009-09-25 JP JP2009221276A patent/JP2011070944A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012111908A (en) * | 2010-11-26 | 2012-06-14 | Nippon Shokubai Co Ltd | Polymer particle, conductive particulate using the same, and anisotropic conductive material |
| JP2018149813A (en) * | 2011-07-13 | 2018-09-27 | ヌボトロニクス、インク． | Method for manufacturing electronic and mechanical structure |
| WO2021206201A1 (en) * | 2020-04-10 | 2021-10-14 | 주식회사 씨앤씨머티리얼즈 | Conductive polymer particles containing nickel metal layer |
| WO2021206202A1 (en) * | 2020-04-10 | 2021-10-14 | 주식회사 씨앤씨머티리얼즈 | Conductive polymer particles containing silver metal layer |
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