JP5406544B2 - Method for producing conductive fine particles, and conductive fine particles - Google Patents
Method for producing conductive fine particles, and conductive fine particles Download PDFInfo
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Description
本発明は、粒子が２個以上結合した連結粒子が少なく信頼性の高い導電接続ができる導電性微粒子、及び、連結粒子が少ない導電性微粒子を得ることができる導電性微粒子の製造方法に関する。 The present invention relates to a conductive fine particle that can provide highly reliable conductive connection with few connected particles in which two or more particles are bonded, and a method for producing conductive fine particles that can obtain conductive fine particles with few connected particles.
導電性微粒子は、バインダー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 fine particles are mixed and kneaded with a binder resin or an adhesive, for example, an anisotropic conductive paste, an anisotropic conductive ink, an anisotropic conductive adhesive, an 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、回路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回路基板に電気的に接続したりするために、相対向する回路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 used to electrically connect circuit boards to each other, for example, in electronic devices such as liquid crystal displays, personal computers, and mobile phones, and to electrically connect small components such as semiconductor elements to the circuit board. For this reason, it is used by being sandwiched between circuit boards and electrode terminals facing each other.
従来、異方性導電材料に対して好適な導電性微粒子は、粒子径の均一な樹脂微粒子やガラスビーズ等の微粒子を基材微粒子として用い、基材微粒子の表面にニッケル等の金属によるメッキ層を形成させた導電性微粒子が報告されていた。 Conventionally, conductive fine particles suitable for anisotropic conductive materials are resin fine particles having a uniform particle diameter or fine particles such as glass beads as substrate fine particles, and a plating layer made of a metal such as nickel on the surface of the substrate fine particles There have been reported conductive fine particles having formed therein.
このような導電性微粒子を製造する方法は、例えば、基材微粒子を特許文献１に示されるようなパラジウム触媒液で処理し、基材微粒子の表面にパラジウム触媒を付着させ、更にこの基材微粒子を無電解メッキ液に分散させることにより金属メッキ層を形成させる方法が挙げられる。 A method for producing such conductive fine particles includes, for example, treating the substrate fine particles with a palladium catalyst solution as disclosed in Patent Document 1, attaching the palladium catalyst to the surface of the substrate fine particles, and further, the substrate fine particles. There is a method of forming a metal plating layer by dispersing in an electroless plating solution.
近年、電子部品の小型化が進んでいるため、隣接する電極間の距離が短くなる傾向にある。このため、平均粒子径の小さい導電性微粒子が求められている。
しかしながら、従来の方法で平均粒子径の小さい導電性微粒子を作製すると、作製段階で導電性微粒子が凝集してしまうため、得られる導電性微粒子を隣接する電極間の距離が近接する電子部品の接続に用いた場合に、隣接する電極間で短絡が発生してしまうという問題があった。
In recent years, since electronic components have been miniaturized, the distance between adjacent electrodes tends to be short. For this reason, electroconductive fine particles with a small average particle diameter are calculated | required.
However, if conductive fine particles with a small average particle diameter are produced by the conventional method, the conductive fine particles are aggregated in the production stage. Therefore, the obtained conductive fine particles are connected to an electronic component in which the distance between adjacent electrodes is close. When used in the above, there is a problem that a short circuit occurs between adjacent electrodes.
これに対して、特許文献２には、微粒子が凝集した凝集粒子の混入を排除することを目的として、微粒子の平均粒子径の１．７〜３倍の孔径を有するメッシュを用いて分級工程を行う導電性微粒子の製造方法が開示されている。
しかしながら、このような方法では、凝集粒子を排除することはできるものの、微粒子が２個結合した連結粒子を排除することができず、得られる導電性微粒子中に連結粒子が多数存在した。特に、連結粒子が多数存在する導電性微粒子が異方性導電材料に用いられた場合、連結粒子に起因する隣接する電極間の短絡が発生していた。
On the other hand, Patent Document 2 discloses a classification step using a mesh having a pore size 1.7 to 3 times the average particle size of the fine particles for the purpose of eliminating mixing of the aggregated particles in which the fine particles are aggregated. A method for producing conductive fine particles is disclosed.
However, in such a method, although aggregated particles can be excluded, connected particles in which two fine particles are bonded cannot be excluded, and there are many connected particles in the obtained conductive fine particles. In particular, when conductive fine particles having a large number of connected particles are used for the anisotropic conductive material, a short circuit between adjacent electrodes due to the connected particles has occurred.
本発明は、粒子が２個以上結合した連結粒子が少なく信頼性の高い導電接続ができる導電性微粒子、及び、連結粒子が少ない導電性微粒子を得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。 The present invention provides a conductive fine particle that can provide highly reliable conductive connection with few connected particles in which two or more particles are bonded, and a method for producing conductive fine particles that can obtain conductive fine particles with few connected particles. For the purpose.
本発明は、基材微粒子と、前記基材微粒子の表面に形成された下地金属層と、前記下地金属層の表面に形成された導電層とを有する導電性微粒子であって、シースフロー電気抵抗方式粒度分布計を用いて粒子径分布を測定した場合、平均粒子径の１．２６倍以上の粒子径を有する導電性微粒子の比率が８％以下である導電性微粒子である。
以下に、本発明を詳述する。
The present invention is a conductive fine particle comprising a base particle, a base metal layer formed on the surface of the base particle, and a conductive layer formed on the surface of the base metal layer, and a sheath flow electrical resistance When the particle size distribution is measured using a system particle size distribution meter, the proportion of conductive fine particles having a particle size of 1.26 times or more of the average particle size is 8% or less.
The present invention is described in detail below.
本発明者らは、シースフロー電気抵抗方式粒度分布計を用いて測定した場合に、平均粒子径の１．２６倍以上の粒子径を有する導電性微粒子の比率が８％以下である導電性微粒子は、凝集粒子だけでなく、粒子が２個以上結合した連結粒子の数も極めて少ないことから、このような導電性微粒子を用いることで、信頼性の極めて高い導電接続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 inventors have a conductive fine particle in which the ratio of conductive fine particles having a particle size of 1.26 times or more of the average particle size is 8% or less when measured using a sheath flow electric resistance type particle size distribution analyzer. Finds that not only the aggregated particles but also the number of connected particles in which two or more particles are bonded is extremely small, and by using such conductive fine particles, highly reliable conductive connection can be achieved. It came to complete.
本発明の導電性微粒子は、基材微粒子と、前記基材微粒子の表面に形成された下地金属層と、前記下地金属層の表面に形成された導電層とを有する。 The conductive fine particles of the present invention include substrate fine particles, a base metal layer formed on the surface of the base particle, and a conductive layer formed on the surface of the base metal layer.
上記基材微粒子は特に限定されず、適度な弾性率、弾性変形性及び復元性を有する基材微粒子であれば、無機材料であっても有機材料であってもよく、樹脂微粒子、無機微粒子、有機無機ハイブリッド微粒子、金属微粒子等が挙げられる。適度な弾性率、弾性変形性及び復元性が制御しやすいため、上記基材微粒子は樹脂微粒子であることが好ましい。 The substrate fine particles are not particularly limited, and may be an inorganic material or an organic material as long as the substrate fine particles have an appropriate elastic modulus, elastic deformability, and resilience. Organic / inorganic hybrid fine particles, metal fine particles and the like can be mentioned. Since the appropriate elastic modulus, elastic deformability, and restoring property can be easily controlled, the substrate fine particles are preferably resin fine particles.
上記樹脂微粒子を構成する樹脂は特に限定されず、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や、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や、ジビニルベンゼン重合樹脂や、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共重合樹脂等が挙げられる。また、上記樹脂微粒子を構成する樹脂として、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。これらの樹脂は、単独で用いられてもよく、２種以上が併用されてもよい。 The resin constituting the resin fine particles is not particularly limited. For example, polyolefins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polytetrafluoroethylene, polyisobutylene, and polybutadiene, polymethyl methacrylate, and polymethyl acrylate. Acrylic resins such as divinylbenzene copolymer resins, divinylbenzene-styrene copolymers, divinylbenzene-acrylic acid ester copolymers, divinylbenzene-methacrylic acid ester copolymer divinylbenzene copolymer resins, etc. . Examples of the resin constituting the resin fine particles include polyalkylene terephthalate, polysulfone, polycarbonate, polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, and the like. These resins may be used alone or in combination of two or more.
上記無機微粒子は特に限定されず、例えば、シリカ、アルミナ等の微粒子が挙げられる。上記有機無機ハイブリッド微粒子は特に限定されず、例えば、オルガノシロキサン骨格の中にアクリルポリマーを含有するハイブリッド微粒子が挙げられる。 The inorganic fine particles are not particularly limited, and examples thereof include fine particles such as silica and alumina. The organic-inorganic hybrid fine particles are not particularly limited, and examples thereof include hybrid fine particles containing an acrylic polymer in an organosiloxane skeleton.
上記基材微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２０μｍである。上記基材微粒子の平均粒子径が０．５μｍ未満であると、例えば、無電解メッキ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る。上記基材微粒子の平均粒子径が２０μｍを超えると、異方性導電材料として基板電極間で用いられる範囲を超えてしまうことがある。上記基材微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１０μｍであり、更に好ましい下限は２μｍ、更に好ましい上限は５μｍである。
なお、上記基材微粒子の平均粒子径は、光学顕微鏡又は電子顕微鏡を用いて無作為に選んだ５０個の基材微粒子の粒子径を測定し、それを算術平均することにより求めることができる。
The average particle diameter of the substrate fine particles is not particularly limited, but a preferable lower limit is 0.5 μm and a preferable upper limit is 20 μm. When the average particle size of the substrate fine particles is less than 0.5 μm, for example, when electroless plating is performed, aggregation tends to occur and it may be difficult to form single particles. When the average particle diameter of the substrate fine particles exceeds 20 μm, it may exceed the range used between the substrate electrodes as the anisotropic conductive material. The more preferable lower limit of the average particle diameter of the substrate fine particles is 1 μm, the more preferable upper limit is 10 μm, the still more preferable lower limit is 2 μm, and the still more preferable upper limit is 5 μm.
The average particle size of the substrate fine particles can be obtained by measuring the particle sizes of 50 randomly selected substrate fine particles using an optical microscope or an electron microscope and arithmetically averaging them.
本発明の導電性微粒子は、基材微粒子の表面に下地金属層を有する。
上記下地金属層を構成する金属は、具体的には、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、ゲルマニウム及びカドミウムからなる群より選択される少なくとも１種の金属が好ましい。なかでも、上記下地金属層の形成が容易であることから、上記下地金属層を構成する金属は、ニッケル、銀、銅であることが好ましい。更に、上記下地金属層は、ニッケル又は銅を含有することが好ましく、ニッケル層又は銅層であることがより好ましい。
The conductive fine particles of the present invention have a base metal layer on the surface of the substrate fine particles.
Specifically, the metal constituting the base metal layer is nickel, gold, silver, copper, platinum, zinc, iron, tin, lead, aluminum, cobalt, indium, chromium, titanium, antimony, bismuth, germanium, and cadmium. At least one metal selected from the group consisting of is preferred. Especially, since formation of the said base metal layer is easy, it is preferable that the metal which comprises the said base metal layer is nickel, silver, and copper. Furthermore, it is preferable that the said base metal layer contains nickel or copper, and it is more preferable that it is a nickel layer or a copper layer.
上記下地金属層の厚さの好ましい下限は０．００５μｍ、好ましい上限は１μｍである。上記下地金属層の厚さが０．００５μｍ未満であると、導電層を形成する効果が得られないことがある。上記下地金属層の厚さが１μｍを超えると、導電層を形成する際に凝集が生じやすく、凝集した導電性微粒子は隣接する電極間の短絡を引き起こすことがある。更に、得られる導電性微粒子の柔軟性が損なわれることがある。 A preferable lower limit of the thickness of the base metal layer is 0.005 μm, and a preferable upper limit is 1 μm. If the thickness of the base metal layer is less than 0.005 μm, the effect of forming a conductive layer may not be obtained. When the thickness of the base metal layer exceeds 1 μm, aggregation is likely to occur when the conductive layer is formed, and the aggregated conductive fine particles may cause a short circuit between adjacent electrodes. Furthermore, the flexibility of the obtained conductive fine particles may be impaired.
本発明の導電性微粒子は、上記下地金属層の表面に導電層を有する。上記導電層は、電極に接触し、電極間を導通させる役割を有する。
上記導電層を構成する金属は、例えば、金、パラジウム、銀、銅、白金、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、カドミウム、珪素等の金属や、ＩＴＯ、ハンダ等の金属化合物が挙げられる。なかでも、導電性に優れることから、上記導電層は、金、銀又はパラジウムを含有することが好ましく、金層、銀層又はパラジウム層であることがより好ましい。なかでも、上記導電層は、金又はパラジウムを含有することが更により好ましく、金層又はパラジウム層であることが特に好ましい。
上記導電層は、単層構造であってもよく、複数の層を有する積層構造であってもよい。積層構造の場合には、最外層を構成する金属は、金又はパラジウムであることが好ましい。
The conductive fine particles of the present invention have a conductive layer on the surface of the base metal layer. The conductive layer has a role of contacting the electrodes and conducting between the electrodes.
Examples of the metal constituting the conductive layer include gold, palladium, silver, copper, platinum, iron, tin, lead, aluminum, cobalt, indium, chromium, titanium, antimony, bismuth, germanium, cadmium, and silicon. And metal compounds such as ITO and solder. Especially, since it is excellent in electroconductivity, it is preferable that the said conductive layer contains gold, silver, or palladium, and it is more preferable that they are a gold layer, a silver layer, or a palladium layer. Especially, it is still more preferable that the said conductive layer contains gold or palladium, and it is especially preferable that it is a gold layer or a palladium layer.
The conductive layer may have a single layer structure or a laminated structure having a plurality of layers. In the case of a laminated structure, the metal constituting the outermost layer is preferably gold or palladium.
上記導電層の厚みは特に限定されないが、好ましい下限は０．００５μｍ、好ましい上限は０．６μｍである。上記導電層の厚みが０．００５μｍ未満であると、導電層としての充分な効果が得られないことがある。上記導電層の厚みが０．６μｍを超えると、得られる導電性微粒子の比重が高くなったり、導電性微粒子の硬さが充分変形できる硬度ではなくなったりすることがある。 Although the thickness of the said conductive layer is not specifically limited, A preferable minimum is 0.005 micrometer and a preferable upper limit is 0.6 micrometer. When the thickness of the conductive layer is less than 0.005 μm, a sufficient effect as the conductive layer may not be obtained. When the thickness of the conductive layer exceeds 0.6 μm, the specific gravity of the obtained conductive fine particles may increase, or the hardness of the conductive fine particles may not be sufficiently deformable.
本発明の導電性微粒子として、具体的には、例えば、基材微粒子と上記基材微粒子の表面に形成されたニッケル層と上記ニッケル層の表面に形成された金層とを有する導電性微粒子や、基材微粒子と上記基材微粒子の表面に形成されたニッケル層と上記ニッケル層の表面に形成されたパラジウム層とを有する導電性微粒子や、基材微粒子と上記基材微粒子の表面に形成された銅層と上記銅層の表面に形成されたパラジウム層とを有する導電性微粒子や、基材微粒子と上記基材微粒子の表面に形成されたニッケル層と上記ニッケル層の表面に形成された銀層とを有する導電性微粒子や、基材微粒子と上記基材微粒子の表面に形成された銅層と上記銅層の表面に形成された金層とを有する導電性微粒子等が挙げられる。 Specific examples of the conductive fine particles of the present invention include, for example, conductive fine particles having base fine particles, a nickel layer formed on the surface of the base fine particles, and a gold layer formed on the surface of the nickel layer. A conductive fine particle having a substrate fine particle, a nickel layer formed on the surface of the substrate fine particle, and a palladium layer formed on the surface of the nickel layer; and formed on the surface of the substrate fine particle and the substrate fine particle. Conductive fine particles having a copper layer and a palladium layer formed on the surface of the copper layer, or a base material fine particle, a nickel layer formed on the surface of the base material fine particle, and silver formed on the surface of the nickel layer Examples thereof include conductive fine particles having a layer, conductive fine particles having substrate fine particles, a copper layer formed on the surface of the substrate fine particles, and a gold layer formed on the surface of the copper layer.
本発明の導電性微粒子は、シースフロー電気抵抗方式粒度分布計を用いて粒度分布を測定した場合、平均粒子径の１．２６倍以上の粒子径を有する導電性微粒子の比率が８％以下である。
平均粒子径の１．２６倍以上の粒子径を有する導電性微粒子の比率を８％以下とすることで、凝集粒子だけでなく、粒子が２個以上結合した連結粒子の数も極めて少なくなり、例えば、本発明の導電性微粒子を異方性導電材料に用いた場合に、短絡の発生を防止することができる。特に、隣接する電極間の距離が短い電子部品の接続に用いる場合、本発明の効果が充分に発揮される。
なお、上記比率とは、上記シースフロー電気抵抗方式粒度分布計を用いて粒度分布を測定したすべての導電性微粒子の個数に対して、平均粒子径の１．２６倍以上の粒子径を有する導電性微粒子の個数の割合を百分率で表した数値である。
When the particle size distribution of the conductive fine particles of the present invention is measured using a sheath flow electric resistance type particle size distribution meter, the ratio of the conductive fine particles having a particle size of 1.26 times or more of the average particle size is 8% or less. is there.
By setting the ratio of the conductive fine particles having a particle diameter of 1.26 times or more of the average particle diameter to 8% or less, not only the aggregated particles but also the number of connected particles in which two or more particles are combined is extremely reduced. For example, when the conductive fine particles of the present invention are used as an anisotropic conductive material, occurrence of a short circuit can be prevented. In particular, when used for connecting electronic components having a short distance between adjacent electrodes, the effects of the present invention are sufficiently exhibited.
The above ratio means that the conductive particles having a particle diameter of 1.26 times or more of the average particle diameter with respect to the number of all conductive fine particles whose particle size distribution was measured using the sheath flow electric resistance type particle size distribution analyzer. It is a numerical value that represents the ratio of the number of functional fine particles as a percentage.
上記平均粒子径の１．２６倍以上の粒子径を有する導電性微粒子の比率が８％を超えると、連結粒子が多くなり、隣接する電極間の距離が短い電子部品の接続に用いる場合に短絡が発生し、信頼性の高い導電接続ができない。上記比率の好ましい上限は２．５％であり、より好ましい上限は１％であり、更に好ましい上限は０．６％であり、特に好ましい上限は０．２％である。
なお、上記シースフロー電気抵抗方式粒度分布計とは、測定対象である粒子が、電極を配置したオリフィスを通過する際の電気抵抗に基づいて粒度分布を測定する装置である。上記シースフロー電気抵抗方式粒度分布計で粒度分布を測定した場合、連結粒子がない場合は、平均粒子径付近に単一のピークが得られる。連結粒子が存在する場合は、平均粒子径付近のピークとは別のピークが得られ、平均粒子径の１．２６倍以上の粒子径を有する導電性微粒子の比率が高くなる。従って、平均粒子径の１．２６倍以上の粒子径を有する導電性微粒子の比率が高い場合、連結粒子が多いと判断することができる。上記シースフロー電気抵抗方式粒度分布計として、例えば、シースフロー型粒度分布計（シスメックス社製「ＳＤ−２０００」）等が挙げられる。なお、測定対象となる導電性微粒子の個数は特に限定されないが、１００００個以上であることが好ましく、具体的には、例えば、３００００個であることがより好ましい。
When the ratio of the conductive fine particles having a particle diameter of 1.26 times or more of the average particle diameter exceeds 8%, the number of connected particles increases, and this is a short circuit when used for connecting an electronic component having a short distance between adjacent electrodes. And reliable conductive connection is not possible. A preferable upper limit of the ratio is 2.5%, a more preferable upper limit is 1%, a still more preferable upper limit is 0.6%, and a particularly preferable upper limit is 0.2%.
The sheath flow electric resistance type particle size distribution analyzer is a device that measures the particle size distribution based on the electric resistance when particles to be measured pass through an orifice in which an electrode is arranged. When the particle size distribution is measured by the sheath flow electric resistance type particle size distribution meter, when there is no connected particle, a single peak is obtained in the vicinity of the average particle diameter. When connected particles are present, a peak different from the peak near the average particle size is obtained, and the ratio of conductive fine particles having a particle size of 1.26 times or more the average particle size is increased. Therefore, when the ratio of the conductive fine particles having a particle diameter of 1.26 times or more of the average particle diameter is high, it can be determined that there are many connected particles. Examples of the sheath flow electric resistance type particle size distribution meter include a sheath flow type particle size distribution meter ("SD-2000" manufactured by Sysmex Corporation). The number of conductive fine particles to be measured is not particularly limited, but is preferably 10,000 or more, and more specifically, for example, more preferably 30,000.
本発明の導電性微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２０μｍである。上記導電性微粒子の平均粒子径が０．５μｍ未満であると、例えば、無電解メッキ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る。上記導電性微粒子の平均粒子径が２０μｍを超えると、異方性導電材料として基板電極間で用いられる範囲を超えてしまうことがある。上記導電性微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１０μｍであり、更に好ましい下限は２μｍ、更に好ましい上限は５μｍである。
なお、上記導電性微粒子の平均粒子径は、光学顕微鏡又は電子顕微鏡を用いて無作為に選んだ５０個の導電性微粒子の粒子径を測定し、それを算術平均することにより求めることができる。
The average particle diameter of the conductive fine particles of the present invention is not particularly limited, but a preferred lower limit is 0.5 μm and a preferred upper limit is 20 μm. When the average particle diameter of the conductive fine particles is less than 0.5 μm, for example, when electroless plating is performed, aggregation tends to occur and it may be difficult to form single particles. When the average particle diameter of the conductive fine particles exceeds 20 μm, the range used between the substrate electrodes as the anisotropic conductive material may be exceeded. The more preferable lower limit of the average particle diameter of the conductive fine particles is 1 μm, the more preferable upper limit is 10 μm, the still more preferable lower limit is 2 μm, and the still more preferable upper limit is 5 μm.
The average particle diameter of the conductive fine particles can be obtained by measuring the particle diameters of 50 conductive fine particles selected at random using an optical microscope or an electron microscope and arithmetically averaging them.
本発明の導電性微粒子の製造方法は、上述した平均粒子径の１．２６倍以上の粒子径を有する導電性微粒子の比率が８％以下である導電性微粒子が得られる方法であれば、特に限定されない。例えば、表面に下地金属層が形成された基材微粒子を予備分散させる工程１と、前記予備分散された基材微粒子の下地金属層の表面に導電層を形成させる工程２とを有する導電性微粒子の製造方法であって、前記工程１において、表面に下地金属層が形成された基材微粒子を分散させた分散液をろ過する工程を有する導電性微粒子の製造方法が挙げられる。このような導電性微粒子の製造方法もまた本発明の１つである。 The method for producing conductive fine particles of the present invention is particularly a method that can obtain conductive fine particles having a ratio of conductive fine particles having a particle size of 1.26 times or more of the above-mentioned average particle size of 8% or less. It is not limited. For example, conductive fine particles having a step 1 of preliminarily dispersing substrate fine particles having a base metal layer formed on the surface and a step 2 of forming a conductive layer on the surface of the base metal layer of the pre-dispersed substrate fine particles. A method of producing conductive fine particles, which includes a step of filtering the dispersion in which the fine particles of the base metal layer on the surface of which are dispersed in the step 1 is filtered. Such a method for producing conductive fine particles is also one aspect of the present invention.
上記表面に下地金属層が形成された基材微粒子は、従来公知の方法で製造することができる。上記基材微粒子の表面に下地金属層を形成する方法は特に限定されず、例えば、無電解メッキ、電気メッキ、スパッタリング等の方法が挙げられる。上記基材微粒子が樹脂微粒子である場合、上記下地金属層は、無電解メッキで形成することが好ましい。 The substrate fine particles having the base metal layer formed on the surface can be produced by a conventionally known method. The method for forming the base metal layer on the surface of the substrate fine particles is not particularly limited, and examples thereof include electroless plating, electroplating, and sputtering. When the substrate fine particles are resin fine particles, the base metal layer is preferably formed by electroless plating.
上記表面に下地金属層が形成された基材微粒子を予備分散させる工程１では、表面に下地金属層が形成された基材微粒子を分散させた分散液をろ過する工程を有する。上記表面に下地金属層が形成された基材微粒子が分散している分散液をろ過することで、凝集している基材微粒子を分散させたり、凝集している基材微粒子を除去したりすることができる。 In the step 1 of preliminarily dispersing the substrate fine particles having the base metal layer formed on the surface, there is a step of filtering the dispersion in which the substrate fine particles having the base metal layer formed on the surface are dispersed. By filtering the dispersion in which the substrate fine particles having the base metal layer formed on the surface are dispersed, the aggregated substrate fine particles are dispersed or the aggregated substrate fine particles are removed. be able to.
上記分散液とは、上記表面に下地金属層が形成された基材微粒子と、溶媒とを含有する溶液を意味する。上記溶媒は特に限定されないが、純水、メタノールやエタノール等のアルコール、純水とアルコールとの混合物等を挙げることができる。上記溶媒は、純水であることが好ましい。 The dispersion liquid means a solution containing base material fine particles having a base metal layer formed on the surface and a solvent. Although the said solvent is not specifically limited, Pure water, alcohol, such as methanol and ethanol, the mixture of pure water and alcohol, etc. can be mentioned. The solvent is preferably pure water.
上記分散液における上記表面に下地金属層が形成された基材微粒子の含有量は特に限定されないが、上記表面に下地金属層が形成された基材微粒子の含有量の好ましい下限は３重量％、好ましい上限は５０重量％である。上記表面に下地金属層が形成された基材微粒子の含有量が３〜５０重量％の範囲内であることで、上記表面に下地金属層が形成された基材微粒子の凝集を抑制することができたり、導電性微粒子の生産効率を高めたりすることができる。 The content of the substrate fine particles in which the base metal layer is formed on the surface in the dispersion is not particularly limited, but the preferred lower limit of the content of the substrate fine particles in which the base metal layer is formed on the surface is 3% by weight, A preferred upper limit is 50% by weight. The content of the base particle having the base metal layer formed on the surface is in the range of 3 to 50% by weight, thereby suppressing the aggregation of the base particle having the base metal layer formed on the surface. Or the production efficiency of conductive fine particles can be increased.
上記工程１は、上記表面に下地金属層が形成された基材微粒子を分散させた分散液をろ過する工程を有する。上記表面に下地金属層が形成された基材微粒子を分散させた分散液をろ過する方法として、上記分散液をステンレスメッシュ篩、ナイロン篩等でろ過する方法が挙げられる。上記ろ過を行う際の篩の孔径は特に限定されず、表面に下地金属層が形成された基材微粒子の平均粒子径に応じて、適宜設定することができる。例えば、上記表面に下地金属層が形成された基材微粒子の平均粒子径が２〜５μｍの場合では、篩の孔径は平均粒子径より大きく、かつ、篩の孔径が２０μｍ以下であることが好ましい。 The step 1 includes a step of filtering the dispersion in which the base material fine particles having the base metal layer formed on the surface are dispersed. Examples of a method for filtering the dispersion in which the base material fine particles having the base metal layer formed on the surface are dispersed include a method of filtering the dispersion with a stainless mesh sieve, a nylon sieve, or the like. The pore diameter of the sieve when performing the filtration is not particularly limited, and can be appropriately set according to the average particle diameter of the base material fine particles having the base metal layer formed on the surface. For example, when the average particle diameter of the base particle having the base metal layer formed on the surface is 2 to 5 μm, the pore diameter of the sieve is preferably larger than the average particle diameter and the pore diameter of the sieve is 20 μm or less. .
更に、上記工程１は、表面に下地金属層が形成された基材微粒子を分散させた分散液に超音波を照射する工程を有することが好ましい。上記表面に下地金属層が形成された基材微粒子を分散させた分散液に超音波を照射する工程を有することで、凝集している基材微粒子を分散させることができる。
本発明では、表面に下地金属層が形成された基材微粒子を分散させた分散液に超音波を照射する工程を行った後、表面に下地金属層が形成された基材微粒子を分散させた分散液をろ過する工程を行ってもよく、表面に下地金属層が形成された基材微粒子を分散させた分散液をろ過する工程を行った後、表面に下地金属層が形成された基材微粒子を分散させた分散液に超音波を照射する工程を行ってもよい。
Furthermore, it is preferable that the said process 1 has the process of irradiating an ultrasonic wave to the dispersion liquid which disperse | distributed the base material fine particle in which the base metal layer was formed on the surface. The aggregated substrate fine particles can be dispersed by having a step of irradiating the dispersion liquid in which the substrate fine particles having the base metal layer formed on the surface are dispersed with an ultrasonic wave.
In the present invention, after performing the step of irradiating the dispersion liquid in which the base metal particles having the base metal layer formed on the surface are dispersed, the base particles having the base metal layer formed on the surface are dispersed. The step of filtering the dispersion may be performed, the substrate having the base metal layer formed on the surface after the step of filtering the dispersion in which the fine particles of the base metal layer formed on the surface are dispersed is performed. You may perform the process of irradiating an ultrasonic wave to the dispersion liquid which disperse | distributed microparticles | fine-particles.
例えば、上記工程１として、表面に下地金属層が形成された基材微粒子を分散させた分散液に超音波を照射する工程を行い、次いで、表面に下地金属層が形成された基材微粒子を分散させた分散液をろ過する工程を行うことが好ましい。上記表面に下地金属層が形成された基材微粒子を分散させた分散液に超音波を照射する方法として、上記分散液に超音波洗浄機等で超音波を照射する方法が挙げられる。上記超音波は、超音波領域に振動数を有していれば特に限定されず、適宜設定することができる。
上記工程１は、表面に下地金属層が形成された基材微粒子を分散させた分散液に超音波を照射する工程を有することで、平均粒子径の１．２６倍以上の粒子径を有する導電性微粒子の比率を低下させることができる。
For example, as the step 1, the step of irradiating the dispersion liquid in which the base particle having the base metal layer formed on the surface is dispersed with ultrasonic waves, and then the base particle having the base metal layer formed on the surface is performed. It is preferable to perform a step of filtering the dispersed dispersion. Examples of the method of irradiating the dispersion liquid in which the substrate fine particles having the base metal layer formed on the surface are dispersed with ultrasonic waves include a method of irradiating the dispersion liquid with ultrasonic waves using an ultrasonic cleaner or the like. The ultrasonic wave is not particularly limited as long as it has a frequency in the ultrasonic region, and can be set as appropriate.
The step 1 includes a step of irradiating the dispersion liquid in which the base material fine particles having the base metal layer formed on the surface are dispersed with an ultrasonic wave, so that a conductive material having a particle size of 1.26 times or more of the average particle size. The ratio of conductive fine particles can be reduced.
更に、上記工程１は、表面に下地金属層が形成された基材微粒子と、分散剤とを含有する分散液を調製する工程を有することが好ましい。上記表面に下地金属層が形成された基材微粒子と、分散剤とを含有する分散液を調製する工程を有することで、凝集している基材微粒子を分散させることができる。
本発明では、表面に下地金属層が形成された基材微粒子と、分散剤とを含有する分散液を調製する工程と、表面に下地金属層が形成された基材微粒子を分散させた分散液に超音波を照射する工程と、表面に下地金属層が形成された基材微粒子を分散させた分散液をろ過する工程の順序は特に限定されない。
Further, the step 1 preferably includes a step of preparing a dispersion containing base material fine particles having a base metal layer formed on the surface and a dispersant. The aggregated substrate fine particles can be dispersed by preparing a dispersion containing the substrate fine particles having the base metal layer formed on the surface and a dispersant.
In the present invention, a step of preparing a dispersion containing substrate fine particles having a base metal layer formed on the surface and a dispersant, and a dispersion in which the base fine particles having a base metal layer formed on the surface are dispersed There is no particular limitation on the order of the step of irradiating ultrasonic waves and the step of filtering the dispersion in which the base material fine particles having the base metal layer formed on the surface are dispersed.
例えば、上記工程１として、表面に下地金属層が形成された基材微粒子と、分散剤とを含有する分散液を調製する工程を行い、次いで、表面に下地金属層が形成された基材微粒子を分散させた分散液に超音波を照射する工程を行い、次いで、表面に下地金属層が形成された基材微粒子を分散させた分散液をろ過する工程を行うことがより好ましい。上記表面に下地金属層が形成された基材微粒子と、分散剤とを含有する分散液を調製する方法は、上記表面に下地金属層が形成された基材微粒子と、分散剤と、溶媒とを混合し分散液を調製する方法、上記表面に下地金属層が形成された基材微粒子が分散している分散液に分散剤を添加し分散液を調製する方法等が挙げられる。
上記工程１は、表面に下地金属層が形成された基材微粒子と、分散剤とを含有する分散液を調製する工程を有することで、平均粒子径の１．２６倍以上の粒子径を有する導電性微粒子の比率をより低下させることができる。
For example, as the above step 1, a step of preparing a dispersion containing a substrate fine particle having a surface metal layer formed on the surface and a dispersant, and then a substrate fine particle having a surface metal layer formed on the surface It is more preferable to perform a step of irradiating ultrasonic waves to the dispersion liquid in which is dispersed, and then a step of filtering the dispersion liquid in which the base material fine particles having the base metal layer formed on the surface are dispersed. A method of preparing a dispersion containing a base material fine particle having a base metal layer formed on the surface and a dispersant includes a base material fine particle having a base metal layer formed on the surface, a dispersant, a solvent, And a method of preparing a dispersion by adding a dispersing agent to a dispersion in which base material fine particles having a base metal layer formed on the surface are dispersed.
The above-mentioned step 1 has a step of preparing a dispersion containing a base material fine particle having a base metal layer formed on the surface and a dispersant, and thus has a particle size of 1.26 times the average particle size or more. The ratio of the conductive fine particles can be further reduced.
上記分散剤は、例えば、ポリカルボン酸塩型界面活性剤、アルキル硫酸エステル塩、アルキルベンゼンスルホン酸塩、ポリオキシエチレンアルキルエーテル硫酸エステル塩等を用いることができる。なかでも、上記分散剤は分散性に優れることから、アルキル硫酸エステル塩、ポリオキシエチレンアルキルエーテル硫酸エステル塩が好ましい。 As the dispersant, for example, a polycarboxylate type surfactant, an alkyl sulfate ester salt, an alkyl benzene sulfonate salt, a polyoxyethylene alkyl ether sulfate ester salt, or the like can be used. Especially, since the said dispersing agent is excellent in a dispersibility, alkyl sulfate ester salt and polyoxyethylene alkyl ether sulfate ester salt are preferable.
本発明の導電性微粒子の製造方法は、次いで、上記予備分散された基材微粒子の下地金属層の表面に導電層を形成させる工程２を有する。上記予備分散された基材微粒子の下地金属層の表面に導電層を形成させる方法は、特に限定されず、無電解メッキ、置換メッキ、電気メッキ、スパッタリング等が挙げられる。なかでも、上記工程２において、超音波を照射しながら無電解メッキすることにより、上記予備分散された基材微粒子の下地金属層の表面に導電層を形成させる工程を行うことが好ましい。このような工程を行うことにより、平均粒子径の１．２６倍以上の粒子径を有する導電性微粒子の比率をより低下させることができる。 Next, the method for producing conductive fine particles of the present invention includes a step 2 in which a conductive layer is formed on the surface of the base metal layer of the pre-dispersed substrate fine particles. The method for forming the conductive layer on the surface of the base metal layer of the pre-dispersed substrate fine particles is not particularly limited, and examples include electroless plating, displacement plating, electroplating, and sputtering. In particular, in the step 2, it is preferable to perform a step of forming a conductive layer on the surface of the base metal layer of the base dispersed fine particles by performing electroless plating while irradiating ultrasonic waves. By performing such a process, the ratio of the conductive fine particles having a particle diameter of 1.26 times or more of the average particle diameter can be further reduced.
本発明によれば、粒子が２個以上結合した連結粒子が少なく信頼性の高い導電接続ができる導電性微粒子、及び、連結粒子が少ない導電性微粒子を得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。 According to the present invention, there are provided conductive fine particles that can provide highly reliable conductive connection with few connected particles in which two or more particles are bonded, and a method for producing conductive fine particles that can obtain conductive fine particles with few connected particles. 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）ニッケルメッキ層形成工程
スチレン樹脂微粒子（平均粒子径４μｍ）を、イオン吸着剤１０重量％溶液に５分間浸漬した。その後、スチレン樹脂微粒子を硫酸パラジウム０．０１重量％水溶液に５分間浸漬し、更にジメチルアミンボランを加えてパラジウムイオンを還元し、ろ過、洗浄することにより、パラジウムを担持したスチレン樹脂微粒子を得た。
次いで、コハク酸ナトリウム５ｇとイオン交換水５００ｍｌとを含有する溶液を調製し、得られた溶液とパラジウムを担持したスチレン樹脂微粒子１０ｇとを混合して懸濁液とし、更に硫酸で懸濁液のｐＨを５に調整した。
Example 1
(1) Nickel plating layer forming step Styrene resin fine particles (average particle diameter 4 μm) were immersed in a 10 wt% solution of an ion adsorbent for 5 minutes. Thereafter, the styrene resin fine particles were immersed in a 0.01 wt% palladium sulfate aqueous solution for 5 minutes, and further dimethylamine borane was added to reduce palladium ions, which were filtered and washed to obtain styrene resin fine particles carrying palladium. .
Next, a solution containing 5 g of sodium succinate and 500 ml of ion-exchanged water was prepared, and the resulting solution and 10 g of styrene resin fine particles carrying palladium were mixed to form a suspension. The pH was adjusted to 5.
次に、硫酸ニッケル２０重量％と、次亜リン酸ナトリウム２０重量％と、水酸化ナトリウム８重量％とを含有する前期メッキ溶液を調製した。得られた懸濁液を８０℃に加熱し、前期メッキ溶液を連続的に滴下し、２０分間攪拌することで、メッキ反応させた。メッキ反応中に、微粒子の著しい凝集が無いこと、及び、水素が発生しなくなることを確認し、前期メッキ反応を終了させた。 Next, a pre-plating solution containing 20% by weight of nickel sulfate, 20% by weight of sodium hypophosphite, and 8% by weight of sodium hydroxide was prepared. The obtained suspension was heated to 80 ° C., and the plating solution was added dropwise continuously and stirred for 20 minutes to cause a plating reaction. During the plating reaction, it was confirmed that there was no significant aggregation of fine particles and that hydrogen was not generated, and the previous plating reaction was terminated.
更に、硫酸ニッケル１０重量％と、次亜リン酸ナトリウム５重量％と、水酸化ナトリウム５重量％とを含有する後期メッキ溶液を調製した。前期メッキ反応終了後の溶液に、後期メッキ溶液を連続的に滴下し、１時間攪拌することでメッキ反応させ、ニッケル層が形成されたスチレン樹脂微粒子を得た。 Furthermore, a late plating solution containing 10% by weight of nickel sulfate, 5% by weight of sodium hypophosphite, and 5% by weight of sodium hydroxide was prepared. The late plating solution was continuously dropped into the solution after the completion of the previous plating reaction, and stirred for 1 hour to cause a plating reaction to obtain styrene resin fine particles on which a nickel layer was formed.
（２）予備分散工程
ニッケル層が形成されたスチレン樹脂微粒子を純水２００ｍＬに分散させた後、ステンレスメッシュ篩（孔径１６μｍ）を通過させ、純水中にニッケル層が形成されたスチレン樹脂微粒子を予備分散させた。次いで、ニッケル層が形成されたスチレン樹脂微粒子をろ過、水洗し、アルコールに分散させた後、真空乾燥させ、予備分散したスチレン樹脂微粒子を得た。
(2) Pre-dispersing step After dispersing the styrene resin fine particles on which the nickel layer is formed in 200 mL of pure water, the styrene resin fine particles on which the nickel layer is formed in pure water are passed through a stainless mesh sieve (pore diameter: 16 μm). Pre-dispersed. Next, the styrene resin fine particles on which the nickel layer was formed were filtered, washed with water, dispersed in alcohol, and then vacuum dried to obtain pre-dispersed styrene resin fine particles.
（３）金メッキ層形成工程
予備分散したスチレン樹脂微粒子１０ｇを、シアン化金カリウム５．９ｇを含有する置換金メッキ液２０００ｍＬに添加した。次いで、置換金メッキ液を３００ｒｐｍで攪拌し、７０℃で３０分間置換金メッキ反応させた。反応終了後に得られた微粒子をろ過、水洗し、アルコールに分散させた後、真空乾燥し、厚みが８０ｎｍのニッケルメッキ層及び厚みが３０ｎｍの金メッキ層を有する導電性微粒子を得た。得られた導電性微粒子の平均粒子径は４．２μｍであった。なお、上記導電性微粒子の平均粒子径は、走査型電子顕微鏡（日立ハイテクノロジーズ社製「Ｓ−３０００Ｎ」）にて２０００倍で観察し、無作為に選んだ５０個の導電性微粒子の粒子径を測定し、算術平均することにより求めた。
(3) Gold plating layer forming step 10 g of pre-dispersed styrene resin fine particles were added to 2000 mL of a displacement gold plating solution containing 5.9 g of potassium gold cyanide. Next, the displacement gold plating solution was stirred at 300 rpm and subjected to displacement gold plating reaction at 70 ° C. for 30 minutes. Fine particles obtained after completion of the reaction were filtered, washed with water, dispersed in alcohol, and then vacuum dried to obtain conductive fine particles having a nickel plating layer having a thickness of 80 nm and a gold plating layer having a thickness of 30 nm. The average particle diameter of the obtained conductive fine particles was 4.2 μm. The average particle size of the conductive fine particles was observed with a scanning electron microscope (“S-3000N” manufactured by Hitachi High-Technologies Corporation) at a magnification of 2000, and the particle size of 50 randomly selected conductive fine particles. Was obtained by measuring and arithmetically averaging.
（実施例２）
（２）予備分散工程において、ニッケル層が形成されたスチレン樹脂微粒子を純水２００ｍＬに分散させた後、超音波洗浄機（アズワン社製「ＵＴ−２０６Ｈ」）で、４０ｋＨｚ、２００Ｗの超音波を１０分間照射し、更にステンレスメッシュ篩（孔径１６μｍ）を通過させたこと以外は、実施例１と同様に導電性微粒子を得た。得られた導電性微粒子の平均粒子径は４．２μｍであった。
(Example 2)
(2) In the preliminary dispersion step, the styrene resin fine particles on which the nickel layer is formed are dispersed in 200 mL of pure water, and then ultrasonic waves of 40 kHz and 200 W are applied with an ultrasonic cleaner (“UT-206H” manufactured by ASONE). Conductive fine particles were obtained in the same manner as in Example 1 except that irradiation was carried out for 10 minutes and further passing through a stainless mesh screen (pore diameter: 16 μm). The average particle diameter of the obtained conductive fine particles was 4.2 μm.
（実施例３）
（１）ニッケルメッキ層形成工程において、スチレン樹脂微粒子（平均粒子径３μｍ）を使用した以外は、実施例２と同様に導電性微粒子を得た。得られた導電性微粒子の平均粒子径は３．２μｍであった。
(Example 3)
(1) In the nickel plating layer forming step, conductive fine particles were obtained in the same manner as in Example 2 except that styrene resin fine particles (average particle diameter: 3 μm) were used. The average particle diameter of the obtained conductive fine particles was 3.2 μm.
（実施例４）
（２）予備分散工程において、ニッケル層が形成されたスチレン樹脂微粒子をアルキルベンゼンスルホン酸塩（花王社製「ペレックスＯＴ−Ｐ」）１重量％水溶液２００ｍＬに分散させた後、超音波洗浄機（アズワン社製「ＵＴ−２０６Ｈ」）で、４０ｋＨｚ、２００Ｗの超音波を１０分間照射し、更にステンレスメッシュ篩（孔径１６μｍ）を通過させたこと以外は、実施例３と同様に導電性微粒子を得た。得られた導電性微粒子の平均粒子径は３．２μｍであった。
Example 4
(2) In the preliminary dispersion step, the styrene resin fine particles on which the nickel layer is formed are dispersed in 200 mL of a 1% by weight aqueous solution of alkylbenzene sulfonate (“Perex OT-P” manufactured by Kao Co., Ltd.), and then an ultrasonic cleaner (ASONE) Conductive fine particles were obtained in the same manner as in Example 3 except that the ultrasonic wave of 40 kHz and 200 W was irradiated for 10 minutes with “UT-206H” manufactured by the company and passed through a stainless mesh screen (pore diameter: 16 μm). . The average particle diameter of the obtained conductive fine particles was 3.2 μm.
（実施例５）
（１）ニッケルメッキ層形成工程において、スチレン樹脂微粒子（平均粒子径２．５μｍ）を使用した以外は、実施例２と同様に導電性微粒子を得た。得られた導電性微粒子の平均粒子径は２．７μｍであった。
(Example 5)
(1) In the nickel plating layer forming step, conductive fine particles were obtained in the same manner as in Example 2 except that styrene resin fine particles (average particle size 2.5 μm) were used. The average particle diameter of the obtained conductive fine particles was 2.7 μm.
（実施例６）
（２）予備分散工程において、ニッケル層が形成されたスチレン樹脂微粒子をアルキルベンゼンスルホン酸塩（花王社製「ペレックスＯＴ−Ｐ」）１重量％水溶液２００ｍＬに分散させた後、超音波洗浄機（アズワン社製「ＵＴ−２０６Ｈ」）で、４０ｋＨｚ、２００Ｗの超音波を１０分間照射し、更にステンレスメッシュ篩（孔径１６μｍ）を通過させたこと以外は、実施例５と同様に導電性微粒子を得た。得られた導電性微粒子の平均粒子径は２．７μｍであった。
(Example 6)
(2) In the preliminary dispersion step, the styrene resin fine particles on which the nickel layer is formed are dispersed in 200 mL of a 1% by weight aqueous solution of alkylbenzene sulfonate (“Perex OT-P” manufactured by Kao Co., Ltd.), and then an ultrasonic cleaner (ASONE) Conductive fine particles were obtained in the same manner as in Example 5 except that the ultrasonic wave of 40 kHz and 200 W was irradiated for 10 minutes with “UT-206H” manufactured by the company and further passed through a stainless mesh screen (pore diameter 16 μm). . The average particle diameter of the obtained conductive fine particles was 2.7 μm.
（実施例７）
（２）予備分散工程において、アルキルベンゼンスルホン酸塩に代えて、ポリオキシエチレンアルキルエーテル硫酸エステル（花王社製「エマール２０Ｃ」）を用いた以外は実施例６と同様に導電性微粒子を得た。得られた導電性微粒子の平均粒子径は２．７μｍであった。
(Example 7)
(2) Conductive fine particles were obtained in the same manner as in Example 6 except that polyoxyethylene alkyl ether sulfate (“Emar 20C” manufactured by Kao Corporation) was used in place of the alkylbenzene sulfonate in the preliminary dispersion step. The average particle diameter of the obtained conductive fine particles was 2.7 μm.
（実施例８）
（２）予備分散工程において、アルキルベンゼンスルホン酸塩に代えて、ポリカルボン酸塩型界面活性剤（花王社製「ポイズ５２０」）を用いた以外は実施例６と同様に導電性微粒子を得た。得られた導電性微粒子の平均粒子径は２．７μｍであった。
(Example 8)
(2) In the preliminary dispersion step, conductive fine particles were obtained in the same manner as in Example 6 except that a polycarboxylate type surfactant (“Poise 520” manufactured by Kao Corporation) was used instead of the alkylbenzene sulfonate. . The average particle diameter of the obtained conductive fine particles was 2.7 μm.
（実施例９）
（３）金メッキ層形成工程において、置換金メッキ液を３００ｒｐｍで攪拌し、超音波洗浄機（アズワン社製「ＵＴ−２０６Ｈ」）で、４０ｋＨｚ、２００Ｗの超音波を照射しながら、７０℃で３０分間置換金メッキ反応を行ったこと以外は実施例４と同様に導電性微粒子を得た。得られた導電性微粒子の平均粒子径は３．２μｍであった。
Example 9
(3) In the gold plating layer forming step, the substitution gold plating solution is stirred at 300 rpm, and irradiated with ultrasonic waves of 40 kHz and 200 W with an ultrasonic cleaner (“UT-206H” manufactured by ASONE) for 30 minutes at 70 ° C. Conductive fine particles were obtained in the same manner as in Example 4 except that the displacement gold plating reaction was performed. The average particle diameter of the obtained conductive fine particles was 3.2 μm.
（実施例１０）
（３）金メッキ層形成工程において、置換金メッキ液を３００ｒｐｍで攪拌し、超音波洗浄機（アズワン社製「ＵＴ−２０６Ｈ」）で、４０ｋＨｚ、２００Ｗの超音波を照射しながら、７０℃で３０分間置換金メッキ反応を行った以外は実施例７と同様に導電性微粒子を得た。得られた導電性微粒子の平均粒子径は２．７μｍであった。
(Example 10)
(3) In the gold plating layer forming step, the substitution gold plating solution is stirred at 300 rpm, and irradiated with ultrasonic waves of 40 kHz and 200 W with an ultrasonic cleaner (“UT-206H” manufactured by ASONE) for 30 minutes at 70 ° C. Conductive fine particles were obtained in the same manner as in Example 7 except that the substitution gold plating reaction was performed. The average particle diameter of the obtained conductive fine particles was 2.7 μm.
（実施例１１）
（１）ニッケルメッキ層形成工程及び（２）予備分散工程
実施例３と同様にして予備分散したスチレン樹脂微粒子を得た。
(Example 11)
(1) Nickel plating layer forming step and (2) predispersing step Preliminarily dispersed styrene resin fine particles were obtained in the same manner as in Example 3.
（３）パラジウムメッキ層形成工程
予備分散したスチレン樹脂微粒子１０ｇを蒸留水５００ｍＬに分散させ、微粒子懸濁液を調製した。この懸濁液に、４ｇ／Ｌの硫酸パラジウム（無水物）と、２．４ｇ／Ｌのエチレンジアミンと、３．５ｇ／Ｌの次亜リン酸ナトリウムとを含有する、ｐＨ１０に調整された無電解メッキ液を徐々に添加し、５０℃で攪拌し、超音波洗浄機（アズワン社製「ＵＴ−２０６Ｈ」）で、４０ｋＨｚ、２００Ｗの超音波を照射しながら無電解パラジウムメッキを行った。反応終了後に得られた微粒子をろ過、水洗し、アルコールに分散させた後、真空乾燥し、厚みが８０ｎｍのニッケルメッキ層及び厚みが３０ｎｍのパラジウムメッキ層を有する導電性微粒子を得た。得られた導電性微粒子の平均粒子径は３．２μｍであった。
(3) Palladium plated layer forming step 10 g of pre-dispersed styrene resin fine particles were dispersed in 500 mL of distilled water to prepare a fine particle suspension. This suspension contains 4 g / L of palladium sulfate (anhydride), 2.4 g / L of ethylenediamine, and 3.5 g / L of sodium hypophosphite adjusted to pH 10 The plating solution was gradually added, the mixture was stirred at 50 ° C., and electroless palladium plating was performed using an ultrasonic cleaner (“UT-206H” manufactured by ASONE) while irradiating ultrasonic waves of 40 kHz and 200 W. Fine particles obtained after completion of the reaction were filtered, washed with water, dispersed in alcohol, and then vacuum dried to obtain conductive fine particles having a nickel plating layer having a thickness of 80 nm and a palladium plating layer having a thickness of 30 nm. The average particle diameter of the obtained conductive fine particles was 3.2 μm.
（実施例１２）
（１）ニッケルメッキ層形成工程及び（２）予備分散工程
実施例４と同様にして予備分散したスチレン樹脂微粒子を得た。
(Example 12)
(1) Nickel plating layer forming step and (2) preliminary dispersion step Preliminarily dispersed styrene resin fine particles were obtained in the same manner as in Example 4.
（３）パラジウムメッキ層形成工程
予備分散したスチレン樹脂微粒子１０ｇを蒸留水５００ｍＬに分散させ、微粒子懸濁液を調製した。この懸濁液に、４ｇ／Ｌの硫酸パラジウム（無水物）と、２．４ｇ／Ｌのエチレンジアミンと、３．５ｇ／Ｌの次亜リン酸ナトリウムとを含有する、ｐＨ１０に調整された無電解メッキ液を徐々に添加し、５０℃で攪拌し、超音波洗浄機（アズワン社製「ＵＴ−２０６Ｈ」）で、４０ｋＨｚ、２００Ｗの超音波を照射しながら無電解パラジウムメッキを行った。反応終了後に得られた微粒子をろ過、水洗し、アルコールに分散させた後、真空乾燥し、厚みが８０ｎｍのニッケルメッキ層及び厚みが３０ｎｍのパラジウムメッキ層を有する導電性微粒子を得た。得られた導電性微粒子の平均粒子径は３．２μｍであった。
(3) Palladium plated layer forming step 10 g of pre-dispersed styrene resin fine particles were dispersed in 500 mL of distilled water to prepare a fine particle suspension. This suspension contains 4 g / L of palladium sulfate (anhydride), 2.4 g / L of ethylenediamine, and 3.5 g / L of sodium hypophosphite adjusted to pH 10 The plating solution was gradually added, the mixture was stirred at 50 ° C., and electroless palladium plating was performed using an ultrasonic cleaner (“UT-206H” manufactured by ASONE) while irradiating ultrasonic waves of 40 kHz and 200 W. Fine particles obtained after completion of the reaction were filtered, washed with water, dispersed in alcohol, and then vacuum dried to obtain conductive fine particles having a nickel plating layer having a thickness of 80 nm and a palladium plating layer having a thickness of 30 nm. The average particle diameter of the obtained conductive fine particles was 3.2 μm.
（実施例１３）
（１）ニッケルメッキ層形成工程及び（２）予備分散工程
実施例３と同様にして予備分散したスチレン樹脂微粒子を得た。
(Example 13)
(1) Nickel plating layer forming step and (2) predispersing step Preliminarily dispersed styrene resin fine particles were obtained in the same manner as in Example 3.
（３）銀メッキ層形成工程
銀塩として硝酸銀４．２５ｇを純水１１８０ｍＬに室温で溶解した溶液に、還元剤としてベンズイミダゾール１５ｇを加えて溶解し、当初生成した沈殿が完全に溶解したのを確認した後、錯化剤としてコハク酸イミド２５ｇ、クエン酸１水和物３．５ｇを溶解し、その後、結晶調整剤としてグリオキシル酸１０ｇを投入し完全溶解させ無電解銀メッキ液を調製した。
予備分散したスチレン樹脂微粒子１０ｇを、無電解銀メッキ液に投入し、この溶液を攪拌し、超音波洗浄機（アズワン社製「ＵＴ−２０６Ｈ」）で、４０ｋＨｚ、２００Ｗの超音波を照射しながら、加熱して温度を７０℃に保った。その後、ブフナー漏斗でろ過して微粒子を分離し、分離した微粒子に純水約１０００ｍＬを振り掛け洗浄した。その後、アルコール置換を行い、真空乾燥し、厚みが８０ｎｍのニッケルメッキ層及び厚みが３０ｎｍの銀メッキ層を有する導電性微粒子を得た。得られた導電性微粒子の平均粒子径は３．２μｍであった。
(3) Silver plating layer forming step To a solution in which 4.25 g of silver nitrate was dissolved in 1180 mL of pure water at room temperature as a silver salt, 15 g of benzimidazole was added as a reducing agent and dissolved, and the initially generated precipitate was completely dissolved. After confirmation, 25 g of succinimide and 3.5 g of citric acid monohydrate were dissolved as a complexing agent, and then 10 g of glyoxylic acid was added as a crystal modifier and completely dissolved to prepare an electroless silver plating solution.
10 g of pre-dispersed styrene resin fine particles are put into an electroless silver plating solution, this solution is stirred, and ultrasonic waves of 40 kHz and 200 W are irradiated with an ultrasonic cleaner (“UT-206H” manufactured by ASONE). The temperature was kept at 70 ° C. by heating. Thereafter, the fine particles were separated by filtration through a Buchner funnel, and about 1000 mL of pure water was sprinkled and washed on the separated fine particles. Then, alcohol substitution was performed and vacuum-dried, and conductive fine particles having a nickel plating layer having a thickness of 80 nm and a silver plating layer having a thickness of 30 nm were obtained. The average particle diameter of the obtained conductive fine particles was 3.2 μm.
（実施例１４）
（１）ニッケルメッキ層形成工程及び（２）予備分散工程
実施例４と同様にして予備分散したスチレン樹脂微粒子を得た。
(Example 14)
(1) Nickel plating layer forming step and (2) preliminary dispersion step Preliminarily dispersed styrene resin fine particles were obtained in the same manner as in Example 4.
（３）銀メッキ層形成工程
銀塩として硝酸銀４．２５ｇを純水１１８０ｍＬに室温で溶解した溶液に、還元剤としてベンズイミダゾール１５ｇを加えて溶解し、当初生成した沈殿が完全に溶解したのを確認した後、錯化剤としてコハク酸イミド２５ｇ、クエン酸１水和物３．５ｇを溶解し、その後、結晶調整剤としてグリオキシル酸１０ｇを投入し完全溶解させ無電解銀メッキ液を調製した。
予備分散したスチレン樹脂微粒子１０ｇを、無電解銀メッキ液に投入し、この溶液を攪拌し、超音波洗浄機（アズワン社製「ＵＴ−２０６Ｈ」）で、４０ｋＨｚ、２００Ｗの超音波を照射しながら、加熱して温度を７０℃に保った。その後、ブフナー漏斗でろ過して微粒子を分離し、分離した微粒子に純水約１０００ｍＬを振り掛け洗浄した。その後、アルコール置換を行い、真空乾燥し、厚みが８０ｎｍのニッケルメッキ層及び厚みが３０ｎｍの銀メッキ層を有する導電性微粒子を得た。得られた導電性微粒子の平均粒子径は３．２μｍであった。
(3) Silver plating layer forming step To a solution in which 4.25 g of silver nitrate was dissolved in 1180 mL of pure water at room temperature as a silver salt, 15 g of benzimidazole was added as a reducing agent and dissolved, and the initially generated precipitate was completely dissolved. After confirmation, 25 g of succinimide and 3.5 g of citric acid monohydrate were dissolved as a complexing agent, and then 10 g of glyoxylic acid was added as a crystal modifier and completely dissolved to prepare an electroless silver plating solution.
10 g of pre-dispersed styrene resin fine particles are put into an electroless silver plating solution, this solution is stirred, and ultrasonic waves of 40 kHz and 200 W are irradiated with an ultrasonic cleaner (“UT-206H” manufactured by ASONE). The temperature was kept at 70 ° C. by heating. Thereafter, the fine particles were separated by filtration through a Buchner funnel, and about 1000 mL of pure water was sprinkled and washed on the separated fine particles. Then, alcohol substitution was performed and vacuum-dried, and conductive fine particles having a nickel plating layer having a thickness of 80 nm and a silver plating layer having a thickness of 30 nm were obtained. The average particle diameter of the obtained conductive fine particles was 3.2 μm.
（実施例１５）
（１）銅メッキ層形成工程
スチレン樹脂微粒子（平均粒子径３μｍ）を、イオン吸着剤１０重量％溶液に５分間浸漬した。その後、スチレン樹脂微粒子を硫酸パラジウム０．０１重量％水溶液に５分間浸漬し、更にジメチルアミンボランを加えてパラジウムイオンを還元し、ろ過、洗浄することにより、パラジウムを担持したスチレン樹脂微粒子を得た。
得られたパラジウムを担持したスチレン樹脂微粒子に蒸留水５００ｍＬを加え、微粒子懸濁液を調製した。この懸濁液に、４０ｇ／Ｌの硫酸銅（５水和物）と、１００ｇ／Ｌのエチレンジアミン四酢酸（ＥＤＴＡ）と、５０ｇ／Ｌのグルコン酸ナトリウムと、２５ｇ／Ｌのホルムアルデヒドとを含有する、ｐＨ１０．５に調整された無電解メッキ液を徐々に添加し、５０℃で攪拌しながら無電解銅メッキを行い、銅層が形成されたスチレン樹脂微粒子を得た。
(Example 15)
(1) Copper plating layer forming step Styrene resin fine particles (average particle size 3 μm) were immersed in a 10 wt% solution of an ion adsorbent for 5 minutes. Thereafter, the styrene resin fine particles were immersed in a 0.01 wt% palladium sulfate aqueous solution for 5 minutes, and further dimethylamine borane was added to reduce palladium ions, which were filtered and washed to obtain styrene resin fine particles carrying palladium. .
Distilled water (500 mL) was added to the resulting palladium-supported styrene resin fine particles to prepare a fine particle suspension. This suspension contains 40 g / L copper sulfate (pentahydrate), 100 g / L ethylenediaminetetraacetic acid (EDTA), 50 g / L sodium gluconate, and 25 g / L formaldehyde. Then, an electroless plating solution adjusted to pH 10.5 was gradually added, and electroless copper plating was performed with stirring at 50 ° C. to obtain styrene resin fine particles on which a copper layer was formed.
（２）予備分散工程
銅層が形成されたスチレン樹脂微粒子を純水２００ｍＬに分散させた後、超音波洗浄機（アズワン社製「ＵＴ−２０６Ｈ」）で、４０ｋＨｚ、２００Ｗの超音波を１０分間照射し、ステンレスメッシュ篩（孔径１６μｍ）を通過させ、純水中に銅層が形成されたスチレン樹脂微粒子を予備分散させた。次いで、銅層が形成されたスチレン樹脂微粒子をろ過、水洗し、アルコールに分散させた後、真空乾燥させ、予備分散したスチレン樹脂微粒子を得た。
(2) Pre-dispersing step After the styrene resin fine particles with the copper layer formed are dispersed in 200 mL of pure water, ultrasonic waves of 40 kHz and 200 W are applied for 10 minutes with an ultrasonic cleaner (“UT-206H” manufactured by ASONE). Irradiated, passed through a stainless mesh screen (pore size 16 μm), and pre-dispersed styrene resin fine particles having a copper layer formed in pure water. Next, the styrene resin fine particles on which the copper layer was formed were filtered, washed with water, dispersed in alcohol, and then vacuum dried to obtain pre-dispersed styrene resin fine particles.
（３）パラジウムメッキ層形成工程
予備分散したスチレン樹脂微粒子１０ｇを蒸留水５００ｍＬに分散させ、微粒子懸濁液を調整した。この懸濁液に、４ｇ／Ｌの硫酸パラジウム（無水物）と、２．４ｇ／Ｌのエチレンジアミンと、３．５ｇ／Ｌの次亜リン酸ナトリウムとを含有する、ｐＨ１０に調整された無電解メッキ液を徐々に添加し、５０℃で攪拌し、超音波洗浄機（アズワン社製「ＵＴ−２０６Ｈ」）で、４０ｋＨｚ、２００Ｗの超音波を照射しながら無電解パラジウムメッキを行った。反応終了後に得られた微粒子をろ過、水洗し、アルコールに分散させた後、真空乾燥し、厚みが８０ｎｍの銅メッキ層及び厚みが３０ｎｍのパラジウムメッキ層を有する導電性微粒子を得た。得られた導電性微粒子の平均粒子径は３．２μｍであった。
(3) Palladium plating layer forming step 10 g of pre-dispersed styrene resin fine particles were dispersed in 500 mL of distilled water to prepare a fine particle suspension. This suspension contains 4 g / L of palladium sulfate (anhydride), 2.4 g / L of ethylenediamine, and 3.5 g / L of sodium hypophosphite adjusted to pH 10 The plating solution was gradually added, the mixture was stirred at 50 ° C., and electroless palladium plating was performed using an ultrasonic cleaner (“UT-206H” manufactured by ASONE) while irradiating ultrasonic waves of 40 kHz and 200 W. Fine particles obtained after completion of the reaction were filtered, washed with water, dispersed in alcohol, and then vacuum dried to obtain conductive fine particles having a copper plating layer having a thickness of 80 nm and a palladium plating layer having a thickness of 30 nm. The average particle diameter of the obtained conductive fine particles was 3.2 μm.
（実施例１６）
（２）予備分散工程において、銅層が形成されたスチレン樹脂微粒子をアルキルベンゼンスルホン酸塩（花王社製「ペレックスＯＴ−Ｐ」）１重量％水溶液２００ｍＬに分散させた後、超音波洗浄機（アズワン社製「ＵＴ−２０６Ｈ」）で、４０ｋＨｚ、２００Ｗの超音波を１０分間照射し、更にステンレスメッシュ篩（孔径１６μｍ）を通過させたこと以外は、実施例１５と同様に導電性微粒子を得た。得られた導電性微粒子の平均粒子径は３．２μｍであった。
(Example 16)
(2) In the preliminary dispersion step, the styrene resin fine particles on which the copper layer is formed are dispersed in 200 mL of a 1% by weight aqueous solution of alkylbenzene sulfonate (“Perex OT-P” manufactured by Kao Co., Ltd.), and then an ultrasonic cleaner (ASONE) Conductive fine particles were obtained in the same manner as in Example 15 except that the ultrasonic wave of 40 kHz and 200 W was irradiated for 10 minutes with “UT-206H” manufactured by the company and further passed through a stainless mesh screen (pore diameter: 16 μm). . The average particle diameter of the obtained conductive fine particles was 3.2 μm.
（比較例１）
（２）予備分散工程を行わなかった以外は、実施例１と同様に導電性微粒子を得た。得られた導電性微粒子の平均粒子径は４．２μｍであった。
(Comparative Example 1)
(2) Conductive fine particles were obtained in the same manner as in Example 1 except that the preliminary dispersion step was not performed. The average particle diameter of the obtained conductive fine particles was 4.2 μm.
（比較例２）
（２）予備分散工程を行わなかった以外は、実施例３と同様に導電性微粒子を得た。得られた導電性微粒子の平均粒子径は３．２μｍであった。
(Comparative Example 2)
(2) Conductive fine particles were obtained in the same manner as in Example 3 except that the preliminary dispersion step was not performed. The average particle diameter of the obtained conductive fine particles was 3.2 μm.
（比較例３）
（２）予備分散工程を行わなかった以外は、実施例５と同様に導電性微粒子を得た。得られた導電性微粒子の平均粒子径は２．７μｍであった。
(Comparative Example 3)
(2) Conductive fine particles were obtained in the same manner as in Example 5 except that the preliminary dispersion step was not performed. The average particle diameter of the obtained conductive fine particles was 2.7 μm.
（比較例４）
（２）予備分散工程を行わなかった以外は、実施例１と同様に導電性微粒子を得た。その後、得られた導電性微粒子を、ステンレスメッシュ篩（孔径１６μｍ）に通過させた。得られた導電性微粒子の平均粒子径は４．２μｍであった。
(Comparative Example 4)
(2) Conductive fine particles were obtained in the same manner as in Example 1 except that the preliminary dispersion step was not performed. Thereafter, the obtained conductive fine particles were passed through a stainless mesh sieve (pore diameter: 16 μm). The average particle diameter of the obtained conductive fine particles was 4.2 μm.
＜評価＞
実施例１〜１６、及び、比較例１〜４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 in Examples 1-16 and Comparative Examples 1-4. The results are shown in Table 1.
（粒子径分布測定）
実施例１〜１６、及び、比較例１〜４で得られた導電性微粒子を、粒子濃度が４００×１０３個／ｍＬ〜８００×１０３個／ｍＬとなるようにパーティクルシース液（シスメックス社製）に添加して検体とした。シースフロー型粒度分布計（シスメックス社製「ＳＤ−２０００」、ピークカウントモード）を用いて検体の粒子径分布（導電性微粒子のカウント数３００００個）を測定し、平均粒子径の１．２６倍以上の粒子径を有する導電性微粒子の比率を算出した。
(Particle size distribution measurement)
Particle sheath liquid (Sysmex Corporation) so that the conductive fine particles obtained in Examples 1 to 16 and Comparative Examples 1 to 4 have a particle concentration of 400 × 10 3 particles / mL to 800 × 10 3 particles / mL. To make a specimen. Using a sheath flow type particle size distribution analyzer ("SD-2000" manufactured by Sysmex Corporation, peak count mode), the particle size distribution of the specimen (the count number of conductive fine particles is 30000) is measured and is 1.26 times the average particle size. The ratio of conductive fine particles having the above particle diameter was calculated.
（凝集性評価）
実施例１〜１６、及び、比較例１〜４で得られた導電性微粒子を走査型電子顕微鏡（日立ハイテクノロジーズ社製「Ｓ−３０００Ｎ」）にて２０００倍で観察し、任意の導電性微粒子１０万個中において、導電性微粒子が５個以上凝集している凝集粒子の個数を確認した。
(Coagulation evaluation)
The conductive fine particles obtained in Examples 1 to 16 and Comparative Examples 1 to 4 were observed with a scanning electron microscope ("S-3000N" manufactured by Hitachi High-Technologies Corporation) at 2000 times, and any conductive fine particles Among 100,000 particles, the number of aggregated particles in which 5 or more conductive fine particles aggregated was confirmed.
（導通性評価）
実施例１〜１６、及び、比較例１〜４で得られた導電性微粒子を用いて、以下の方法により異方性導電フィルムを作製した。
(Conductivity evaluation)
Using the conductive fine particles obtained in Examples 1 to 16 and Comparative Examples 1 to 4, anisotropic conductive films were produced by the following method.
樹脂バインダーとしてエポキシ樹脂（油化シェルエポキシ社製「エピコート８２８」）１００重量部、トリスジメチルアミノエチルフェノール２重量部、及び、トルエン１００重量部を、遊星式攪拌機を用いて充分に混合した後、離型フィルム上に乾燥後の厚さが１０μｍとなるように塗布し、トルエンを揮発させて接着性フィルムを得た。
次いで、樹脂バインダーとしてエポキシ樹脂（油化シェルエポキシ社製「エピコート８２８」）１００重量部、トリスジメチルアミノエチルフェノール２重量部、及び、トルエン１００重量部に、得られた導電性微粒子を添加し、遊星式攪拌機を用いて充分に混合した後、離型フィルム上に乾燥後の厚さが７μｍとなるように塗布し、トルエンを揮発させて導電性微粒子を含有する接着性フィルムを得た。なお、導電性微粒子の配合量は、フィルム中の含有量が５万個／ｃｍ２となるようにした。
得られた接着性フィルムと導電性微粒子を含有する接着性フィルムとを常温でラミネートすることにより、２層構造を有する厚さ１７μｍの異方性導電フィルムを得た。
After thoroughly mixing 100 parts by weight of an epoxy resin (“Epicoat 828” manufactured by Yuka Shell Epoxy Co., Ltd.), 2 parts by weight of trisdimethylaminoethylphenol, and 100 parts by weight of toluene as a resin binder using a planetary stirrer, It applied so that the thickness after drying might be set to 10 micrometers on a release film, and toluene was volatilized, and the adhesive film was obtained.
Next, the obtained conductive fine particles were added to 100 parts by weight of an epoxy resin (“Epicoat 828” manufactured by Yuka Shell Epoxy Co., Ltd.) as a resin binder, 2 parts by weight of trisdimethylaminoethylphenol, and 100 parts by weight of toluene, After sufficiently mixing using a planetary stirrer, it was applied on a release film so that the thickness after drying was 7 μm, and toluene was volatilized to obtain an adhesive film containing conductive fine particles. In addition, the compounding quantity of electroconductive fine particles was made for the content in a film to be 50,000 piece / cm < 2 >.
By laminating the obtained adhesive film and an adhesive film containing conductive fine particles at room temperature, an anisotropic conductive film having a two-layer structure and a thickness of 17 μm was obtained.
得られた異方性導電フィルムを３ｃｍ×４ｃｍの大きさに切断した。これを、一方に抵抗測定用の引き回し線を有したアルミニウム電極（幅５０μｍ、長さ１ｍｍ、高さ０．２μｍ、配線ピッチ（隣接する電極間の距離）＝２０、１５又は１０μｍ）を有するガラス基板のほぼ中央に貼り付けた後、同じアルミニウム電極を有するガラス基板を、電極同士が重なるように位置合わせをして貼り合わせた。なお、各ガラス基板は合計１０本のアルミニウム電極を有していた。
このガラス基板の接合部を、４０ＭＰａ、１３０℃の圧着条件で熱圧着した後、電極間のリーク電流の有無を確認した。電極間にリーク電流がある場合を「○」、リーク電流がない場合を「×」とした。また、電極間にリーク電流がある場合には、何カ所でリークを起こしているかを確認した。
The obtained anisotropic conductive film was cut into a size of 3 cm × 4 cm. This is a glass having an aluminum electrode (width 50 μm, length 1 mm, height 0.2 μm, wiring pitch (distance between adjacent electrodes) = 20, 15 or 10 μm) having a lead wire for resistance measurement on one side. After affixing almost at the center of the substrate, a glass substrate having the same aluminum electrode was aligned and bonded so that the electrodes overlapped. Each glass substrate had a total of 10 aluminum electrodes.
The bonded portion of this glass substrate was thermocompression bonded under pressure bonding conditions of 40 MPa and 130 ° C., and then the presence or absence of leakage current between the electrodes was confirmed. The case where there was a leakage current between the electrodes was indicated by “◯”, and the case where there was no leakage current was indicated by “X”. In addition, when there was a leak current between the electrodes, it was confirmed where the leak occurred.
実施例で得られた導電性微粒子は、平均粒子径が単一ピークとして検出され、平均粒子径の１．２６倍以上の粒子径を有する導電性微粒子の比率が８％未満となっていることがわかる。
これに対して、比較例で得られた導電性微粒子は、平均粒子径を示すピーク以外にもピークが検出され、平均粒子径の１．２６倍以上の粒子径を有する導電性微粒子の比率が高くなっていることがわかる。
In the conductive fine particles obtained in the examples, the average particle diameter is detected as a single peak, and the ratio of conductive fine particles having a particle diameter of 1.26 times or more of the average particle diameter is less than 8%. I understand.
On the other hand, in the conductive fine particles obtained in the comparative example, a peak was detected in addition to the peak indicating the average particle diameter, and the ratio of the conductive fine particles having a particle diameter of 1.26 times or more of the average particle diameter was You can see that it is getting higher.
本発明によれば、粒子が２個以上結合した連結粒子が少なく信頼性の高い導電接続ができる導電性微粒子、及び、連結粒子が少ない導電性微粒子を得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。 According to the present invention, there are provided conductive fine particles that can provide highly reliable conductive connection with few connected particles in which two or more particles are bonded, and a method for producing conductive fine particles that can obtain conductive fine particles with few connected particles. Can be provided.
Claims (5)
前記予備分散された基材微粒子の下地金属層の表面に導電層を形成させる工程２と
を有する導電性微粒子の製造方法であって、
前記工程１において、表面に下地金属層が形成された基材微粒子を分散させた分散液をろ過する工程を行う
ことを特徴とする導電性微粒子の製造方法。 Step 1 of pre-dispersing fine particles of a base material on which a base metal layer is formed;
A step 2 of forming a conductive layer on the surface of the base metal layer of the pre-dispersed substrate fine particles, and a method for producing conductive fine particles,
In the step 1, a method for producing conductive fine particles, comprising a step of filtering a dispersion in which substrate fine particles having a base metal layer formed on the surface are dispersed.
基材微粒子と、前記基材微粒子の表面に形成された下地金属層と、前記下地金属層の表面に形成された導電層とを有し、シースフロー電気抵抗方式粒度分布計を用いて粒子径分布を測定した場合、平均粒子径の１．２６倍以上の粒子径を有する導電性微粒子の比率が８％以下であるIt has a base particle, a base metal layer formed on the surface of the base particle, and a conductive layer formed on the surface of the base metal layer. When the distribution is measured, the ratio of conductive fine particles having a particle size of 1.26 times or more of the average particle size is 8% or less.
ことを特徴とする導電性微粒子。Conductive fine particles characterized by the above.
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