JP2013151753A - Silver micropowder excellent in affinity for polar medium, and silver ink - Google Patents
Silver micropowder excellent in affinity for polar medium, and silver ink Download PDFInfo
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本発明は、有機物質に被覆された銀ナノ粒子からなる極性媒体との親和性に優れた銀微粉および銀インクに関する。なお、本明細書においては、粒子径が４０ｎｍ以下の粒子を「ナノ粒子」と呼び、ナノ粒子で構成される粉体を「微粉」と呼んでいる。 The present invention relates to a silver fine powder and a silver ink excellent in affinity with a polar medium comprising silver nanoparticles coated with an organic substance. In the present specification, particles having a particle diameter of 40 nm or less are referred to as “nanoparticles”, and a powder composed of nanoparticles is referred to as “fine powder”.
銀ナノ粒子は活性が高く、低温でも焼結が進むため、耐熱性の低い素材に対するパターニング材料として着目されて久しい。特に昨今ではナノテクノロジーの進歩により、シングルナノクラスの粒子の製造も比較的簡便に実施できるようになってきた。 Silver nanoparticles have been attracting attention as a patterning material for materials with low heat resistance because of their high activity and sintering at low temperatures. In recent years, in particular, due to advances in nanotechnology, it has become possible to manufacture single nanoclass particles relatively easily.
特許文献１には酸化銀を出発材料として、アミン化合物を用いて銀ナノ粒子を大量に合成する方法が開示されている。また、特許文献２にはアミンと銀化合物原料を混合し、溶融させることにより銀ナノ粒子を合成する方法が開示されている。非特許文献１には銀ナノ粒子を用いたペーストを作成することが記載されている。特許文献４には液中での分散性が極めて良好な銀ナノ粒子を製造する技術が開示されている。一方、特許文献３には有機保護材Ａで保護した金属ナノ粒子が存在する非極性溶媒に、金属粒子との親和性の良いメルカプト基等の官能基を持つ有機保護材Ｂが溶解した極性溶媒を加えて、撹拌混合することにより、金属ナノ粒子の保護材をＡからＢに交換する手法が開示されている。 Patent Document 1 discloses a method for synthesizing a large amount of silver nanoparticles using an amine compound using silver oxide as a starting material. Patent Document 2 discloses a method of synthesizing silver nanoparticles by mixing and melting an amine and a silver compound raw material. Non-Patent Document 1 describes making a paste using silver nanoparticles. Patent Document 4 discloses a technique for producing silver nanoparticles having extremely good dispersibility in a liquid. On the other hand, Patent Document 3 discloses a polar solvent in which an organic protective material B having a functional group such as a mercapto group having a good affinity for metal particles is dissolved in a nonpolar solvent in which metal nanoparticles protected by the organic protective material A are present. Is added, and a method of exchanging the protective material for metal nanoparticles from A to B by stirring and mixing is disclosed.
銀ナノ粒子の表面は有機保護材により被覆されているのが通常である。この保護材は銀粒子合成反応時に粒子同士を隔離する役割を有する。したがって、ある程度分子量の大きいものを選択することが有利である。分子量が小さいと粒子間距離が狭くなり、湿式の合成反応では反応中に焼結が進んでしまう場合がある。そうなると粒子が粗大化し銀微粉の製造が困難になる。 The surface of the silver nanoparticles is usually covered with an organic protective material. This protective material has a role of separating the particles from each other during the silver particle synthesis reaction. Therefore, it is advantageous to select one having a molecular weight that is somewhat large. If the molecular weight is small, the distance between particles becomes narrow, and in a wet synthesis reaction, sintering may progress during the reaction. If it becomes so, a particle will become coarse and manufacture of a silver fine powder will become difficult.
一方、銀ナノ粒子をインク（本明細書では液状のものに限らず、ある程度粘性の高い有機媒体に銀粒子を分散配合させたペースト状のものも「インク」と称する）として利用する場合には、用途に応じて適切な有機媒体を選択することが望ましい。最近では特に、親水性と親油性の両方を高レベルで兼ね備えた有機媒体を使用するニーズが高まっている。そのような有機媒体は、横軸に有機性（親油性）、縦軸に無機性（親水性）をとった有機概念図において、右上のほうに位置するものが該当する。例えば、実用性をも加味すると、テキサノール（Ｃ12Ｈ24Ｏ3）、テルピネオール（Ｃ10Ｈ18Ｏ）などが例示される。これらは極性有機化合物である。 On the other hand, when silver nanoparticles are used as inks (in this specification, not only liquids but also pastes in which silver particles are dispersed and mixed in an organic medium having a certain degree of viscosity are also referred to as “inks”). It is desirable to select an appropriate organic medium depending on the application. Recently, in particular, there is an increasing need to use an organic medium that has both high hydrophilicity and lipophilicity. Such an organic medium corresponds to an organic conceptual diagram in which the horizontal axis represents organic (lipophilic) and the vertical axis represents inorganic (hydrophilic), which is located on the upper right side. For example, texanol (C 12 H 24 O 3 ), terpineol (C 10 H 18 O) and the like are exemplified when practicality is taken into account. These are polar organic compounds.
しかしながら、そのような性質の有機媒体に分散可能な銀微粉はこれまでに知られていない。銀微粉は、粒子表面を覆う保護材（界面活性剤）の種類によって適用可能な分散媒体の種類が大きく制限される。従来、製造上の制約などから、保護材の種類に対する選択の自由度は非常に小さく、用途に応じて適切な保護材を選択することは極めて困難な状況にある。 However, a silver fine powder that can be dispersed in an organic medium having such properties has not been known so far. As for silver fine powder, the kind of applicable dispersion medium is largely limited by the kind of protective material (surfactant) covering the particle surface. Conventionally, the degree of freedom in selecting the type of protective material is very small due to manufacturing restrictions and the like, and it is extremely difficult to select an appropriate protective material according to the application.
本発明はこのような現状に鑑み、特に、親水性と親油性の両方を高レベルで兼ね備えた有機媒体に対して親和性（すなわち分散性）が良好な銀ナノ粒子を提供しようというものである。 In view of such a current situation, the present invention is intended to provide silver nanoparticles having a good affinity (that is, dispersibility) for an organic medium having both high hydrophilicity and lipophilicity. .
上記目的を達成するために、本発明では、サリチル酸（Ｃ7Ｈ6Ｏ3）、没食子酸（Ｃ7Ｈ6Ｏ5）、ひまし油、コール酸（Ｃ24Ｈ40Ｏ5）、リシノール酸（Ｃ18Ｈ34Ｏ3）の１種以上を表面に吸着させてなるＸ線結晶粒子径Ｄｘ：１〜４０ｎｍ好ましくは１〜１５ｎｍの銀粒子で構成される、少なくともテキサノールおよびテルピネオールとの親和性に優れた銀微粉が提供される。 In order to achieve the above object, in the present invention, salicylic acid (C 7 H 6 O 3 ), gallic acid (C 7 H 6 O 5 ), castor oil, cholic acid (C 24 H 40 O 5 ), ricinoleic acid (C X-ray crystal particle diameter Dx formed by adsorbing one or more of 18 H 34 O 3 ) on the surface: 1 to 40 nm, preferably 1 to 15 nm silver particles, excellent at least affinity with texanol and terpineol A fine silver powder is provided.
サリチル酸は、ベンゼン環にカルボキシル基とヒドロキシ基を有する物質であり、Ｃ6Ｈ4（ＯＨ）−ＣＯＯＨと表すことができる。没食子酸は、３，４，５−トリヒドロキシベンゼンカルボン酸であり、Ｃ6Ｈ2（ＯＨ）3−ＣＯＯＨと表すことができる。リシノール酸は、ＣＨ3（ＣＨ2）5−ＣＨ（ＯＨ）−ＣＨ2ＣＨ＝ＣＨ（ＣＨ2）7−ＣＯＯＨと表すことができる。ひまし油は、リシノール酸（Ｃ18Ｈ34Ｏ3）のトリグリセリドを約９０％含有し、その他の成分としてオレイン酸（Ｃ18Ｈ34Ｏ2）、リノール酸（Ｃ18Ｈ32Ｏ2）のグリセリドと少量の飽和脂肪酸のグリセリドを成分にもつ油脂である。コール酸は、胆汁酸の一種として知られている物質である。これらの有機化合物はいずれもカルボキシル基（親水性）を有しており、カルボキシル基の部分でＡｇ粒子表面に吸着すると考えられる。 Salicylic acid is a substance having a carboxyl group and a hydroxy group on the benzene ring, and can be expressed as C 6 H 4 (OH) —COOH. Gallic acid is 3,4,5-trihydroxybenzenecarboxylic acid and can be expressed as C 6 H 2 (OH) 3 —COOH. Ricinoleic acid can be represented by CH 3 (CH 2) 5 -CH (OH) -CH 2 CH = CH (CH 2) 7 -COOH. Castor oil contains about 90% of triglyceride of ricinoleic acid (C 18 H 34 O 3 ), and glycerin of oleic acid (C 18 H 34 O 2 ) and linoleic acid (C 18 H 32 O 2 ) as other components It is an oil with a small amount of saturated fatty acid glyceride as a component. Cholic acid is a substance known as a kind of bile acid. These organic compounds all have a carboxyl group (hydrophilicity) and are considered to be adsorbed on the surface of the Ag particles at the carboxyl group portion.
また本発明では、カルボキシル基を有する有機化合物を表面に吸着させてなるＸ線結晶粒子径Ｄｘ：１〜４０ｎｍ好ましくは１〜１５ｎｍ（ＴＥＭ観察により測定される平均粒子径ＤTEMで見ると、ＤTEM：３〜４０ｎｍ好ましくは４〜１５ｎｍ）の銀粒子が、テキサノール中あるいはテルピネオール中に分散している銀インクが提供される。当該有機化合物としては、例えばサリチル酸（Ｃ7Ｈ6Ｏ3）、没食子酸（Ｃ7Ｈ6Ｏ5）、ひまし油、コール酸（Ｃ24Ｈ40Ｏ5）、リシノール酸（Ｃ18Ｈ34Ｏ3）が例示され、これらは１種を単独で使用しても良いし、２種以上を複合して使用しても良い。 In the present invention Further, X-ray crystal grain diameter becomes to adsorb organic compounds having a carboxyl group on the surface Dx: from 1 to 40 nm and preferably viewed in an average particle diameter D TEM, as measured by the 1-15 nm (TEM observation, D A silver ink in which silver particles ( TEM : 3 to 40 nm, preferably 4 to 15 nm) are dispersed in texanol or terpineol is provided. Examples of the organic compound include salicylic acid (C 7 H 6 O 3 ), gallic acid (C 7 H 6 O 5 ), castor oil, cholic acid (C 24 H 40 O 5 ), ricinoleic acid (C 18 H 34 O 3). ), And these may be used alone or in combination of two or more.
また極性媒体との親和性に優れた銀粒子の製造方法として、本発明では、不飽和結合を持つ分子量２００〜４００の１級アミンＡに被覆されたＸ線結晶粒子径Ｄｘ：１〜４０ｎｍ好ましくは１〜１５ｎｍ（ＤTEM：３〜４０ｎｍ好ましくは４〜１５ｎｍ）の銀粒子と、カルボキシル基を有する有機化合物Ｂとを、有機化合物Ｂが溶解している極性溶媒Ｃの中で、３０℃以上かつ極性溶媒Ｃの沸点以下の温度域で撹拌混合することにより、銀粒子表面においてアミンＡの脱着と有機化合物Ｂの吸着を生じさせ、有機化合物Ｂを表面に吸着させてなる銀粒子を形成させる工程を有する製造方法が提供される。上記アミンＡとしてはオレイルアミン（Ｃ9Ｈ18＝Ｃ9Ｈ17−ＮＨ2、分子量約２６７）が好適な対象として例示できる。また、有機化合物Ｂとしては、例えばサリチル酸、没食子酸、ひまし油、コール酸、リシノール酸が例示され、これらは１種を単独で使用しても良いし、２種以上を複合して使用しても良い。 As a method for producing silver particles having excellent affinity with a polar medium, in the present invention, X-ray crystal particle diameter Dx coated with primary amine A having an unsaturated bond and having a molecular weight of 200 to 400 is preferably 1 to 40 nm. 1 to 15 nm (D TEM : 3 to 40 nm, preferably 4 to 15 nm) of silver particles and the organic compound B having a carboxyl group, in a polar solvent C in which the organic compound B is dissolved, 30 ° C. or more In addition, by stirring and mixing in a temperature range below the boiling point of the polar solvent C, desorption of amine A and adsorption of organic compound B are caused on the surface of silver particles, and silver particles formed by adsorbing organic compound B on the surface are formed. A manufacturing method having the steps is provided. Examples of the amine A include oleylamine (C 9 H 18 = C 9 H 17 —NH 2 , molecular weight of about 267). Examples of the organic compound B include salicylic acid, gallic acid, castor oil, cholic acid, and ricinoleic acid. These may be used alone or in combination of two or more. good.
本発明によれば、テキサノールやテルピネオールといった、親水性と親油性の両方を兼ね備えた有機媒体に対して優れた分散性を示す銀ナノ粒子が提供可能になった。この銀ナノ粒子で構成される銀微粉は、種々の用途での使用が期待される。一例を挙げると、ミクロンオーダーの粒径を有する一般的な銀粉に、ナノ粒子からなる銀微粉を混合して混合銀粉にすると、全体としての焼結温度が大幅に低下すると考えられる。しかし、一般的な銀粉が使用される極性溶媒中で高い分散性を示す銀ナノ粒子が存在しなかったことから、そのような混合銀粉を得ることは従来極めて困難であった。本発明の銀微粉を用いるとそのような混合銀粉の調製が容易になり、焼結温度を大幅に低下させた極めてコストパフォーマンスの高い銀インクの製造が可能になると期待される。 ADVANTAGE OF THE INVENTION According to this invention, the silver nanoparticle which shows the outstanding dispersibility with respect to the organic medium which has both hydrophilic property and lipophilicity, such as texanol and terpineol, can be provided now. The silver fine powder composed of the silver nanoparticles is expected to be used in various applications. For example, it is considered that when the silver fine powder composed of nanoparticles is mixed with a general silver powder having a particle size of micron order to obtain a mixed silver powder, the sintering temperature as a whole is greatly reduced. However, since no silver nanoparticles exhibiting high dispersibility existed in polar solvents in which general silver powder is used, it has been extremely difficult to obtain such mixed silver powder. When the silver fine powder of the present invention is used, preparation of such a mixed silver powder is facilitated, and it is expected that it is possible to produce a silver ink with extremely high cost performance in which the sintering temperature is greatly reduced.
従来、銀ナノ粒子の製造においては、製造上の制約から、保護材（界面活性剤）の種類を自由に選択することはできなかった。ところが、後述する方法に従えば、保護材の種類に対する選択の自由度をかなり拡大させることが可能になり、これまで存在しなかった種々の銀ナノ粒子を得ることができた。そして、カルボキシル基を有する有機化合物を表面に吸着させてなるＸ線結晶粒子径Ｄｘ：１〜４０ｎｍ好ましくは１〜１５ｎｍ（ＴＥＭ観察により測定される平均粒子径ＤTEMで見ると、ＤTEM：３〜４０ｎｍ好ましくは４〜１５ｎｍ）の銀粒子が、テキサノールあるいはテルピネオールといった親水性と親油性の両方を兼ね備えた有機媒体中に分散している新規な銀インクが実現された。 Conventionally, in the production of silver nanoparticles, the type of protective material (surfactant) could not be freely selected due to production limitations. However, according to the method described later, the degree of freedom of selection with respect to the type of protective material can be considerably increased, and various silver nanoparticles that have not existed so far can be obtained. Then, the organic compound becomes adsorbed onto the surface of the X-ray crystal particle diameter having a carboxyl group Dx: from 1 to 40 nm and preferably viewed in an average particle diameter D TEM, as measured by the 1-15 nm (TEM observation, D TEM: 3 A novel silver ink was realized in which silver particles (˜40 nm, preferably 4-15 nm) were dispersed in an organic medium having both hydrophilicity and lipophilicity, such as texanol or terpineol.
テキサノールやテルピネオールなどの親水性と親油性の両方を高レベルで兼ね備えた有機媒体に対する銀ナノ粒子の分散性を顕著に向上させる保護材物質（界面活性剤）として、サリチル酸、没食子酸、ひまし油成分、コール酸、リシノール酸などが例示できることが明らかになった。これらの有機化合物はカルボキシル基を有しており、銀粒子の表面に吸着されやすい性質を持っている。 As a protective material (surfactant) that significantly improves the dispersibility of silver nanoparticles in organic media that have both high hydrophilicity and lipophilicity such as texanol and terpineol, salicylic acid, gallic acid, castor oil component, It became clear that cholic acid, ricinoleic acid, etc. can be illustrated. These organic compounds have a carboxyl group and have the property of being easily adsorbed on the surface of silver particles.
このような銀ナノ粒子は、例えば「銀粒子合成工程」および「保護材置換工程」を経て得ることができる。以下、その代表的な方法を例示する。 Such silver nanoparticles can be obtained through, for example, a “silver particle synthesis step” and a “protective material replacement step”. Hereinafter, the typical method is illustrated.
《銀粒子合成工程》
特許文献４に開示されるような湿式工程により、粒径の揃った銀ナノ粒子を合成することができる。この合成法は、アルコール中またはポリオール中で、アルコールまたはポリオールを還元剤として、銀化合物を還元処理することにより銀粒子を析出させるものである。ところが、発明者らのその後の研究によれば、より大量生産に適した合成法が見出され、本出願人は特願２００７−２６４５９８に開示した。これは、銀化合物を１級アミンと２−オクタノールの混合液中に溶解させ、これを１２０〜１８０℃に保持することにより２−オクタノールの還元力を利用して銀粒子を析出させるものである。ここでは、この新たな合成法を簡単に例示する。
《Silver particle synthesis process》
Silver nanoparticles having a uniform particle diameter can be synthesized by a wet process as disclosed in Patent Document 4. In this synthesis method, silver particles are precipitated by reducing the silver compound in alcohol or polyol using alcohol or polyol as a reducing agent. However, according to the inventors' subsequent studies, a synthesis method suitable for mass production was found, and the present applicant disclosed in Japanese Patent Application No. 2007-264598. In this method, silver particles are precipitated using a reducing power of 2-octanol by dissolving a silver compound in a mixed solution of a primary amine and 2-octanol and maintaining the temperature at 120 to 180 ° C. . Here, this new synthesis method is illustrated briefly.
銀イオン供給源として銀化合物（例えば硝酸銀）、析出した銀粒子の保護材として１級アミンＡ（不飽和結合を持つ分子量２００〜４００のもの、例えばオレイルアミン）、および溶媒成分であるともに還元剤でもある２−オクタノールを用意する。 A silver compound (for example, silver nitrate) as a silver ion source, a primary amine A (having a molecular weight of 200 to 400 having an unsaturated bond, for example, oleylamine) as a protective material for precipitated silver particles, and a solvent component as well as a reducing agent A certain 2-octanol is prepared.
所定量の１級アミンＡ、２−オクタノールおよび銀化合物を混合して、アミンＡと２−オクタノールとの混合溶媒中に銀化合物が溶解している溶液を作成する。還元反応開始時の液組成が下記（i）〜（iii）を同時に満たすことが好適である。
（i）アミンＡ／銀のモル比：１〜５、
（ii）２−オクタノール／銀のモル比：０.５〜３、
（iii）２−オクタノール／アミンＡのモル比：０.５〜２
A predetermined amount of primary amine A, 2-octanol and a silver compound are mixed to prepare a solution in which a silver compound is dissolved in a mixed solvent of amine A and 2-octanol. It is preferable that the liquid composition at the start of the reduction reaction satisfies the following (i) to (iii) at the same time.
(I) Amine A / silver molar ratio: 1-5,
(Ii) 2-octanol / silver molar ratio: 0.5-3;
(Iii) 2-octanol / amine A molar ratio: 0.5-2
液の昇温を開始して１２０〜１８０℃の温度範囲で保持する。１２０℃を下回る温度では還元反応の進行が進みにくいので高い還元率を安定して得ることが難しくなる。ただし、沸点を大きく超えないようにすることが肝要である。２−オクタノールの沸点は約１７８℃であり、１８０℃程度までは許容できる。１２５〜１７８℃の範囲とすることがより好ましい。大気圧下で実施することができ、反応容器の気相部を窒素ガス等の不活性ガスでパージしながら還流状態とすることが好ましい。撹拌は、あまり強く行わなくても銀ナノ粒子を析出させることができるが、反応容器のサイズが大きくなると、ある程度の撹拌は必要となる。２−オクタノールの場合、他のアルコール（例えばイソブタノール）を使用する場合に比べ、粒径の揃った銀粒子を合成する上で、撹拌強度の自由度が拡がる。なお、２−オクタノールは初めから必要な全量を混合しておいてもよいし、昇温途中または昇温後に混合してもよい。還元反応開始後に２−オクタノールを適宜添加（追加投入）しても構わない。上記温度範囲での保持時間を０.５時間以上確保することが望ましいが、上記（i）〜（iii）を満たす液組成の場合だと１時間程度で反応はほとんど終了に近づくものと考えられ、それ以上保持時間を長くしても還元率に大きな変化は見られない。通常、３時間以下の保持時間を設定すれば十分である。還元反応が進行して銀粒子が析出すると、アミンＡで被覆された銀ナノ粒子が存在するスラリーが得られる。 The temperature of the liquid is started and maintained in a temperature range of 120 to 180 ° C. At temperatures below 120 ° C., the progress of the reduction reaction is difficult to proceed, so it is difficult to stably obtain a high reduction rate. However, it is important not to greatly exceed the boiling point. The boiling point of 2-octanol is about 178 ° C., and it is acceptable up to about 180 ° C. It is more preferable to set it as the range of 125-178 degreeC. The reaction can be performed under atmospheric pressure, and it is preferable to bring the reaction vessel into a reflux state while purging the gas phase portion with an inert gas such as nitrogen gas. Although silver nanoparticles can be precipitated even if stirring is not carried out very strongly, a certain amount of stirring is required as the size of the reaction vessel increases. In the case of 2-octanol, the degree of freedom of stirring strength is broadened when synthesizing silver particles having a uniform particle diameter as compared with the case of using another alcohol (for example, isobutanol). Note that 2-octanol may be mixed in the necessary amount from the beginning, or may be mixed during or after the temperature increase. You may add (additional addition) 2-octanol suitably after a reduction reaction start. It is desirable to secure a holding time of 0.5 hours or more in the above temperature range, but in the case of a liquid composition satisfying the above (i) to (iii), the reaction is considered to be almost completed in about 1 hour. Even if the holding time is further increased, no significant change is observed in the reduction rate. Usually, it is sufficient to set a holding time of 3 hours or less. When silver particles are precipitated by the progress of the reduction reaction, a slurry in which silver nanoparticles coated with amine A are present is obtained.
次いで、上記のスラリーから、デカンテーションや遠心分離によって固形分を回収する。回収された固形分は、１級アミンＡを成分とする保護材に被覆された銀ナノ粒子を主体とするものである。 Next, the solid content is recovered from the slurry by decantation or centrifugation. The recovered solid content is mainly composed of silver nanoparticles coated with a protective material containing primary amine A as a component.
上記の固形分には不純物が付着しているので、メタノールやイソプロパノールを用いた洗浄に供することが好ましい。 Since impurities are adhering to the above-mentioned solid content, it is preferable to use for washing with methanol or isopropanol.
以上のようにして、１級アミンＡに被覆されたＸ線結晶粒子径Ｄｘ：１〜４０ｎｍ好ましくは１〜１５ｎｍの銀粒子を構成することができる。透過型電子顕微鏡（ＴＥＭ）を用いた粒子の観察により求まる平均粒子径ＤTEMは３〜４０ｎｍ好ましくは４〜１５ｎｍ程度の範囲である。 As described above, X-ray crystal particle diameter Dx coated with primary amine A: 1 to 40 nm, preferably 1 to 15 nm, can be formed. The average particle diameter D TEM determined by observation of particles using a transmission electron microscope (TEM) is in the range of 3 to 40 nm, preferably about 4 to 15 nm.
《保護材置換工程》
次に銀粒子に付着している保護材をアミンＡから目的物質である有機化合物Ｂに付け替える操作を行う。本発明の銀粒子の製造方法はこの工程を採用するところに特徴がある。
有機化合物Ｂとしてカルボキシル基を有するものを適用する。カルボキシル基は銀に吸着しやすい性質を有する。上記のアミンＡは不飽和結合を有する分子量２００−４００のアミンであり、銀に対する吸着力はカルボキシル基を持つ物質に比べ弱いと考えられる。したがって、アミンＡに被覆された銀粒子の表面近傍に十分な量の有機化合物Ｂの分子が存在していると、銀表面からアミンＡが脱着するとともに有機化合物Ｂが吸着しやすい状況となり、比較的容易に置換が進行する。
《Protective material replacement process》
Next, an operation of replacing the protective material adhering to the silver particles from the amine A to the organic compound B which is the target substance is performed. The method for producing silver particles of the present invention is characterized in that this step is employed.
An organic compound B having a carboxyl group is applied. The carboxyl group has a property of being easily adsorbed on silver. The above amine A is an amine having an unsaturated bond and a molecular weight of 200-400, and the adsorption power for silver is considered to be weaker than that of a substance having a carboxyl group. Therefore, if a sufficient amount of organic compound B molecules are present in the vicinity of the surface of the silver particles coated with amine A, the situation is such that amine A is desorbed from the silver surface and organic compound B is easily adsorbed. The replacement proceeds easily.
ただし、この置換は溶媒中で進行するので、有機化合物Ｂは溶媒中に溶解していることが必要である。有機化合物Ｂは、テキサノールやテルピネオールといった極性媒体に対して親和力の高い性質のものが選択されるので、有機化合物Ｂを溶解させる溶媒としても極性溶媒が採用される。具体的にはイソプロパノール、メタノール、エタノール、デカリン等の溶媒のうち、溶解性のよいものを選択すればよい。イソプロパノールに良く溶解する有機化合物Ｂの場合は、コスト的にイソプロパノールを選択することが有利となる場合が多い。有機化合物Ｂが溶解している上記のような極性溶媒Ｃの中に、アミンＡに被覆された銀ナノ粒子を存在させ、３０℃以上かつ極性溶媒Ｃの沸点以下の温度域で撹拌する。３０℃より低温では置換が進行しにくい。極性溶媒Ｃにイソプロパノールを使用する場合だと、３５〜８０℃の範囲で行うことが好ましい。アミンＡに被覆された粒子は一般に極性溶媒Ｃに対する分散性が悪く、液中で沈降しやすいので撹拌しなければならないが、あまり強く撹拌する必要はなく、粒子が液中に浮遊した状態を維持できる程度でよい。 However, since this substitution proceeds in a solvent, the organic compound B must be dissolved in the solvent. Since the organic compound B is selected to have a high affinity for a polar medium such as texanol or terpineol, a polar solvent is also used as a solvent for dissolving the organic compound B. Specifically, a solvent having good solubility may be selected from solvents such as isopropanol, methanol, ethanol and decalin. In the case of the organic compound B that dissolves well in isopropanol, it is often advantageous to select isopropanol in terms of cost. Silver nanoparticles coated with amine A are present in the polar solvent C as described above in which the organic compound B is dissolved, and the mixture is stirred in a temperature range of 30 ° C. or more and the boiling point of the polar solvent C or less. Substitution is difficult to proceed at a temperature lower than 30 ° C. When isopropanol is used as the polar solvent C, it is preferably carried out in the range of 35 to 80 ° C. Particles coated with amine A are generally poorly dispersible in the polar solvent C and tend to settle in the liquid, so they must be stirred, but they do not need to be stirred too strongly, and the particles remain floating in the liquid. As much as possible.
アミンＡとカルボキシル基をもつ有機化合物Ｂの置き換え反応は、数分程度の比較的短時間で起きていると考えられるが、工業的に安定した品質のものを供給するという観点から、１時間以上の置き換え反応時間を確保することが望ましい。ただし、２４時間を超えても更なる置き換え反応はあまり進行しないので、２４時間以内で置き換え反応を終了させるのが実用的である。置換に要する反応時間は１〜７時間の範囲で設定することが好ましい。 The replacement reaction of amine A and organic compound B having a carboxyl group is considered to occur in a relatively short time of about several minutes, but from the viewpoint of supplying an industrially stable quality, it takes 1 hour or more. It is desirable to secure a replacement reaction time for. However, since the further replacement reaction does not proceed much even after 24 hours, it is practical to terminate the replacement reaction within 24 hours. The reaction time required for the substitution is preferably set in the range of 1 to 7 hours.
具体的には、予め有機化合物Ｂを極性溶媒Ｃに完全に溶解させた液を作成し、この液と、固形分として回収されたアミンＡが付着している銀ナノ粒子とを１つの容器に収容し、撹拌混合すればよい。有機化合物Ｂが常温で液体である場合、本明細書でいう「有機化合物Ｂが溶解している極性溶媒Ｃ」とは、有機化合物Ｂが極性溶媒Ｃの中で分離することなく両者が均一に混ざり合っている状態を意味する。粒子中の金属Ａｇに対する有機化合物Ｂの当量Ｂ／Ａｇは、０.５〜１０当量とすることが好ましい。ここで、Ａｇ１モルに対し、有機化合物Ｂのカルボキシル基１個が１当量に相当する。極性溶媒Ｃの液量は銀ナノ粒子が液中を浮遊するに足る量が確保される範囲で設定すればよい。 Specifically, a liquid in which the organic compound B is completely dissolved in the polar solvent C is prepared in advance, and this liquid and the silver nanoparticles to which the amine A recovered as a solid content is attached in one container. What is necessary is just to accommodate and to stir and mix. In the case where the organic compound B is liquid at room temperature, the “polar solvent C in which the organic compound B is dissolved” as used herein means that the organic compound B is not separated in the polar solvent C, and the two are uniform. It means a mixed state. The equivalent B / Ag of the organic compound B to the metal Ag in the particles is preferably 0.5 to 10 equivalents. Here, one carboxyl group of the organic compound B corresponds to 1 equivalent with respect to 1 mol of Ag. The amount of the polar solvent C may be set within a range that secures an amount sufficient for the silver nanoparticles to float in the solution.
このようにして有機化合物Ｂを表面に吸着させてなる銀粒子を形成させたのち、固液分離を行い、例えば「分離回収された固形分に洗浄液（例えばメタノールやイソプロパノール）を添加して超音波分散を加えた後、液を遠心分離して固形分を回収する」という操作を数回繰り返すことにより、付着している不純物を洗浄除去することが好ましい。洗浄後の粒子は、Ｘ線結晶粒子径Ｄｘが１〜４０ｎｍ好ましくは１〜１５ｎｍ、ＴＥＭ観察により測定される平均粒子径ＤTEMは３〜４０ｎｍ好ましくは４〜１５ｎｍといった銀ナノ粒子であり、表面には有機化合物Ｂを吸着させてなる界面活性剤を有している。洗浄後の固形分を、テキサノールやテルピネオールといった目的とする溶媒中に分散させることにより銀インクを得ることができる。 After silver particles formed by adsorbing organic compound B on the surface in this way are formed, solid-liquid separation is performed. For example, “cleaning liquid (for example, methanol or isopropanol) is added to the separated solid component and ultrasonic waves are added. After adding the dispersion, it is preferable to wash and remove the adhering impurities by repeating the operation of “centrifuge the liquid to recover the solid content” several times. The particles after washing are silver nanoparticles having an X-ray crystal particle diameter Dx of 1 to 40 nm, preferably 1 to 15 nm, and an average particle diameter D TEM measured by TEM observation of 3 to 40 nm, preferably 4 to 15 nm. Has a surfactant formed by adsorbing the organic compound B. A silver ink can be obtained by dispersing the solid content after washing in a target solvent such as texanol or terpineol.
《実施例１》
下記の方法で１級アミンＡを保護材とする銀粒子を合成し、その後、保護材をアミンＡから有機化合物Ｂに置換した。
本例では１級アミンＡとしてオレイルアミン、有機化合物Ｂとしてサリチル酸をそれぞれ使用し、以下の工程に従った。
Example 1
Silver particles having primary amine A as a protective material were synthesized by the following method, and then the protective material was replaced from amine A to organic compound B.
In this example, oleylamine was used as the primary amine A, and salicylic acid was used as the organic compound B, and the following steps were followed.
〔銀粒子合成工程〕
オレイルアミン（和光純薬株式会社製特級試薬）、２−オクタノール（和光純薬株式会社製特級試薬）、硝酸銀結晶（関東化学株式会社製特級試薬）を用意した。
２−オクタノールと、オレイルアミンと、硝酸銀結晶を混合して、硝酸銀が完全に溶解した液を作成した。配合は以下のとおりである。
・オレイルアミン／銀のモル比＝２.５
・アルコール／銀のモル比＝２.０
・アルコール／オレイルアミンのモル比＝２.０／２.５＝０.８
[Silver particle synthesis process]
Oleylamine (special grade reagent manufactured by Wako Pure Chemical Industries, Ltd.), 2-octanol (special grade reagent manufactured by Wako Pure Chemical Industries, Ltd.), and silver nitrate crystal (special grade reagent manufactured by Kanto Chemical Co., Ltd.) were prepared.
2-Octanol, oleylamine, and silver nitrate crystals were mixed to prepare a solution in which silver nitrate was completely dissolved. The formulation is as follows.
・ Mole ratio of oleylamine / silver = 2.5
-Alcohol / silver molar ratio = 2.0
Alcohol / oleylamine molar ratio = 2.0 / 2.5 = 0.8
上記配合の液２０００ｍＬを準備し、還流器の付いた容器に移してオイルバスに載せ、１４０℃まで昇温速度０.５℃／ｍｉｎで昇温した。その後、プロペラにより１００ｒｐｍで撹拌し、容器の気相部に窒素ガスを２０００ｍＬ／ｍｉｎの流量で供給してパージしながら、還流状態で１４０℃に１時間保持した。その後、加熱を止め、冷却した。 A liquid (2000 mL) having the above composition was prepared, transferred to a container equipped with a refluxer, placed on an oil bath, and heated to 140 ° C. at a heating rate of 0.5 ° C./min. Thereafter, the mixture was stirred at 100 rpm with a propeller, and kept at 140 ° C. for 1 hour in a reflux state while purging by supplying nitrogen gas to the gas phase part of the vessel at a flow rate of 2000 mL / min. Thereafter, heating was stopped and cooling was performed.
反応後のスラリー５００ｇにイソプロパノール１７００ｇを混合しプロペラにより４００ｒｐｍで１時間撹拌し、その後、遠心分離により銀粒子を回収した。このようにして洗浄されたスラリー中にはアミンＡ（オレイルアミン）に被覆された銀粒子が存在している。 1700 g of isopropanol was mixed with 500 g of the slurry after the reaction, and the mixture was stirred with a propeller at 400 rpm for 1 hour, and then silver particles were collected by centrifugation. Silver particles coated with amine A (oleylamine) are present in the slurry thus washed.
別途、これと同一の条件で作成した洗浄後のスラリーについて、少量の固形分サンプルを採取して、下記の要領でＸ線結晶粒子径Ｄｘを求めた。その結果、置換前の銀微粉のＤｘは約７ｎｍであることが確認された。また、下記の要領で平均粒子径ＤTEMを求めた。その結果、置換前の銀微粉のＤTEMは約８ｎｍであることが確認された。
また、上記と同一の条件で作成した洗浄後のスラリーから、オレイルアミンに被覆された置換前の銀微粉を回収し、昇温速度は１０℃／ｍｉｎでＴＧ−ＤＴＡ測定を行った。そのＤＴＡ曲線を図１に示す。図１において、２００〜３００℃の間にある大きな山および３００〜３３０℃の間にあるピークはアミンＡであるオレイルアミンに起因するものであると考えられる。
なお、このスラリー５００ｇ中には金属Ａｇ：約１モルが存在することが別途測定により判っている。
Separately, a small amount of solid sample was collected from the washed slurry prepared under the same conditions as above, and the X-ray crystal particle diameter Dx was determined in the following manner. As a result, it was confirmed that Dx of the silver fine powder before substitution was about 7 nm. Moreover, the average particle diameter DTEM was calculated | required in the following way. As a result, it was confirmed D TEM of the silver fine powder before substitution is about 8 nm.
Moreover, the silver fine powder before substitution coated with oleylamine was recovered from the washed slurry prepared under the same conditions as described above, and TG-DTA measurement was performed at a heating rate of 10 ° C./min. The DTA curve is shown in FIG. In FIG. 1, the large peak between 200 and 300 ° C. and the peak between 300 and 330 ° C. are considered to be attributed to oleylamine, which is amine A.
In addition, it has been proved by measurement separately that about 1 mol of metal Ag is present in 500 g of the slurry.
＜Ｘ線結晶粒子径Ｄｘの測定＞
銀粒子の固形分サンプルをガラス製セルに塗り、Ｘ線回折装置にセットし、Ａｇ（１１１）面の回折ピークを用いて、下記（１）式に示すＳｃｈｅｒｒｅｒの式によりＸ線結晶粒径ＤXを求めた。Ｘ線にはＣｕ−Ｋαを用いた。
Ｄｘ＝Ｋ・λ／（β・ｃｏｓθ） ……（１）
ただし、ＫはＳｃｈｅｒｒｅｒ定数で、０.９４を採用した。λはＣｕ−Ｋα線のＸ線波長、βは上記回折ピークの半価幅、θは回折線のブラッグ角である。
<Measurement of X-ray crystal particle diameter Dx>
A solid sample of silver particles is applied to a glass cell, set in an X-ray diffractometer, and the diffraction peak of the Ag (111) plane is used. X was determined. Cu-Kα was used for X-rays.
Dx = K · λ / (β · cos θ) (1)
However, K is a Scherrer constant and 0.94 is adopted. λ is the X-ray wavelength of the Cu—Kα ray, β is the half width of the diffraction peak, and θ is the Bragg angle of the diffraction line.
＜平均粒子径ＤTEMの測定＞
銀粒子分散液を透過型電子顕微鏡（ＴＥＭ）により観察し、重なっていない独立した３００個の銀粒子の粒子径を計測して、平均粒子径を算出した。
<Measurement of average particle diameter D TEM >
The silver particle dispersion was observed with a transmission electron microscope (TEM), and the particle diameters of 300 independent silver particles that did not overlap were measured to calculate the average particle diameter.
〔保護材置換工程〕
有機化合物Ｂとしてサリチル酸（和光純薬株式会社製特級試薬、分子量１３８.１）、極性溶媒Ｃとしてイソプロパノール（和光純薬株式会社製特級試薬、分子量６０.１）を用意した。
サリチル酸１５３.５９ｇと、イソプロパノール４００ｇを混合して、液温を４０℃に保ち、イソプロパノール中にサリチル酸を完全に溶解させた。この液１２７.９９ｇを、アミンＡ（オレイルアミン）に被覆された銀粒子が存在している前記洗浄後のスラリーに添加し、プロペラにて４００ｒｐｍで撹拌した。この撹拌状態を維持しながら４０℃で５時間保持した。この場合、Ａｇに対する有機化合物Ｂの量は１当量となるように有機化合物Ｂの仕込量を調製してある。
[Protective material replacement process]
Salicylic acid (special grade reagent manufactured by Wako Pure Chemical Industries, Ltd., molecular weight 138.1) was prepared as the organic compound B, and isopropanol (special grade reagent manufactured by Wako Pure Chemical Industries, Ltd., molecular weight 60.1) was prepared as the polar solvent C.
153.59 g of salicylic acid and 400 g of isopropanol were mixed, the liquid temperature was kept at 40 ° C., and the salicylic acid was completely dissolved in isopropanol. 127.99 g of this liquid was added to the washed slurry in which silver particles coated with amine A (oleylamine) were present, and the mixture was stirred with a propeller at 400 rpm. While maintaining this stirring state, it was kept at 40 ° C. for 5 hours. In this case, the amount of organic compound B prepared is adjusted so that the amount of organic compound B relative to Ag is 1 equivalent.
得られたスラリーを３０００ｒｐｍ×５ｍｉｎの遠心分離により固液分離し、その後メタノールを用いた洗浄を３回行い、最終的に遠心分離して洗浄後の固形分を得た。洗浄後の固形分を２４０℃で６時間真空乾燥させ、保護材置換後の銀微粉サンプルを得た。
この乾燥後のサンプルについて、前記の方法にてＴＧ−ＤＴＡ測定を行った。そのＤＴＡ曲線を図２に示す。図１（置換前）と図２（置換後）の対比から、保護材は、アミンＡ（オレイルアミン）のほぼ全量が脱着し、有機化合物Ｂ（サリチル酸）に置き換わったものと考えられる。図７にサリチル酸を吸着してなる銀粒子のＴＥＭ写真を示す。
The obtained slurry was subjected to solid-liquid separation by centrifugation at 3000 rpm × 5 min, then washed with methanol three times, and finally centrifuged to obtain a washed solid. The solid content after washing was vacuum dried at 240 ° C. for 6 hours to obtain a silver fine powder sample after replacement of the protective material.
About the sample after this drying, the TG-DTA measurement was performed by the said method. The DTA curve is shown in FIG. From the comparison of FIG. 1 (before substitution) and FIG. 2 (after substitution), it is considered that the protective material was almost completely desorbed of amine A (oleylamine) and replaced with organic compound B (salicylic acid). FIG. 7 shows a TEM photograph of silver particles formed by adsorbing salicylic acid.
このサンプルについて上記の方法でＸ線結晶粒子径Ｄｘおよび平均粒子径ＤTEMを測定したところ、Ｄｘは６.００ｎｍ、ＤTEMは８.７６ｎｍであった。
ＤTEMの算出に使用した個々の粒子の粒子径は、最小値Ｄminが５.３６ｎｍ、最大値Ｄmaxが１４.２１ｎｍであった。粒子径の標準偏差をσDとするとき、「σD／ＤTEM×１００」の値をＣＶ値と呼ぶ。この銀微粉のＣＶ値は１９.４％であった。ＣＶ値が小さいほど銀粒子の粒径は均一化されていると言える。銀インクの用途ではＣＶ値が４０％以下であることが望ましく、１５％以下のものは非常に粒子径が揃っており、種々の微細配線用途に極めて好適である。
When X-ray crystal particle diameter Dx and average particle diameter D TEM were measured for this sample by the above method, Dx was 6.00 nm and D TEM was 8.76 nm.
D particle diameter of each particle used in computing TEM, the minimum value D min is 5.36Nm, the maximum value D max was 14.21Nm. When the standard deviation of the particle diameter is σ D , the value of “σ D / D TEM × 100” is called CV value. The silver fine powder had a CV value of 19.4%. It can be said that the smaller the CV value, the more uniform the particle size of the silver particles. In the use of silver ink, it is desirable that the CV value is 40% or less, and those having a CV value of 15% or less have extremely uniform particle diameters and are extremely suitable for various fine wiring applications.
次に、テキサノールおよびテルピネオールに対する親和性を評価するために分散性試験を行った。テキサノール１０ｇおよびテルピネオール１０ｇをそれぞれビーカーに入れ、前記サンプル（真空乾燥後の銀微粉）０.５ｇを上記各ビーカーの液中に投入し、軽く撹拌して均一に分散させた後、常温で１６８時間静置させた後に、液の濁りや沈降凝集の発生の有無を目視確認することにより親和性を評価した。評価基準としては、１６８時間後に、粒子が完全に沈降してしまい上澄みが透明な状態になっているものは親和性が良好でないと判定し、１６８時間後でも粒子が沈降せずに上澄みがにごっている状態のものを親和性が良好であると判定した。その結果、テキサノール、テルピネオールいずれの場合も、良好な分散性が確認された。すなわち、保護材としてサリチル酸を付着させた銀ナノ粒子は、親水性と親油性の両方を兼ね備えた実用的な有機媒体に対して分散しやく、親和性をに優れていることがわかった。 Next, a dispersibility test was performed to evaluate the affinity for texanol and terpineol. 10 g of texanol and 10 g of terpineol were put in a beaker, 0.5 g of the sample (silver fine powder after vacuum drying) was put into the solution of each beaker, and the mixture was lightly stirred and dispersed uniformly, and then at room temperature for 168 hours. After allowing to stand, the affinity was evaluated by visually confirming the presence or absence of turbidity of the liquid and the occurrence of sedimentation aggregation. As an evaluation standard, after 168 hours, particles are completely settled and the supernatant is in a transparent state, and it is determined that the affinity is not good, and even after 168 hours, the particles are not settled and the supernatant is covered. Those having a good affinity were determined. As a result, good dispersibility was confirmed for both texanol and terpineol. That is, it was found that silver nanoparticles to which salicylic acid was attached as a protective material were easily dispersed in a practical organic medium having both hydrophilicity and lipophilicity and had excellent affinity.
《参考例》
有機化合物Ｂを没食子酸（和光純薬株式会社製特級試薬、分子量１７０.１）に変えたことを除き、実施例１と同様の実験を行った。
すなわち、保護材置換工程において、没食子酸７８.８３ｇと、イソプロパノール４００ｇを混合して、液温を４０℃に保ち、イソプロパノール中に没食子酸を完全に溶解させた。この液４７８.８３ｇを、アミンＡ（オレイルアミン）に被覆された銀粒子が存在している前記洗浄後のスラリーに添加し、プロペラにて４００ｒｐｍで撹拌した。この撹拌状態を維持しながら４０℃で５時間保持した。この場合、Ａｇに対する有機化合物Ｂの量は０.５当量となるように有機化合物Ｂの仕込量を調製してある。
《Reference example》
The same experiment as in Example 1 was performed, except that the organic compound B was changed to gallic acid (special grade reagent manufactured by Wako Pure Chemical Industries, Ltd., molecular weight 170.1).
That is, in the protective material replacement step, 78.83 g of gallic acid and 400 g of isopropanol were mixed, the liquid temperature was kept at 40 ° C., and gallic acid was completely dissolved in isopropanol. 478.83 g of this liquid was added to the washed slurry in which silver particles coated with amine A (oleylamine) were present, and stirred with a propeller at 400 rpm. While maintaining this stirring state, it was kept at 40 ° C. for 5 hours. In this case, the amount of organic compound B prepared is adjusted so that the amount of organic compound B with respect to Ag is 0.5 equivalent.
得られた乾燥後のサンプルについてのＤＴＡ曲線を図３に示す。図１（置換前）と図３（置換後）の対比から、保護材は、アミンＡ（オレイルアミン）のほぼ全量が脱着し、有機化合物Ｂ（没食子酸）に置き換わったものと考えられる。図８に没食子酸を吸着してなる銀粒子のＴＥＭ写真を示す。
このサンプルについてのＤｘは６.５８ｎｍ、ＤTEMは８.５４ｎｍであった。ＤTEMの算出に使用した個々の粒子の粒子径は、最小値Ｄminが３.９９ｎｍ、最大値Ｄmaxが１３.７３ｎｍであり、この銀微粉のＣＶ値は１９.８％であった。
テキサノールおよびテルピネオールに対する分散性試験の結果、いずれに対しても良好な分散性が確認された。すなわち、保護材として没食子酸を付着させた銀ナノ粒子は、親水性と親油性の両方を兼ね備えた実用的な有機媒体に対して分散しやすいことがわかった。
The DTA curve for the resulting dried sample is shown in FIG. From the comparison of FIG. 1 (before substitution) and FIG. 3 (after substitution), it is considered that the protective material was almost completely desorbed of amine A (oleylamine) and replaced with organic compound B (gallic acid). FIG. 8 shows a TEM photograph of silver particles formed by adsorbing gallic acid.
Dx for this sample 6.58nm, D TEM was 8.54Nm. Particle diameter of each particle used in computing D TEM, the minimum value D min is 3.99Nm, the maximum value D max is 13.73Nm, CV value of the silver micropowder was 19.8%.
As a result of the dispersibility test for texanol and terpineol, good dispersibility was confirmed for both. That is, it was found that silver nanoparticles having gallic acid attached as a protective material are easily dispersed in a practical organic medium having both hydrophilicity and lipophilicity.
《実施例２》
有機化合物Ｂをひまし油に変えたことを除き、実施例１と同様の実験を行った。ひまし油は和光純薬株式会社製のものを使用した。
すなわち、保護材置換工程において、ひまし油２６１.７７ｇと、イソプロパノール４００ｇを混合して、液温を４０℃に保ち、イソプロパノールとひまし油を完全に溶解させた。この液６６１.７７ｇを、アミンＡ（オレイルアミン）に被覆された銀粒子が存在している前記洗浄後のスラリーに添加し、プロペラにて４００ｒｐｍで撹拌した。この撹拌状態を維持しながら４０℃で５時間保持した。この場合、Ａｇに対する有機化合物Ｂの量は１当量となるようにひまし油の仕込量を調製してある。
Example 2
The same experiment as in Example 1 was performed except that the organic compound B was changed to castor oil. Castor oil manufactured by Wako Pure Chemical Industries, Ltd. was used.
That is, in the protective material replacement step, 261.77 g of castor oil and 400 g of isopropanol were mixed, the liquid temperature was kept at 40 ° C., and isopropanol and castor oil were completely dissolved. 66.77 g of this liquid was added to the washed slurry in which silver particles coated with amine A (oleylamine) were present, and the mixture was stirred with a propeller at 400 rpm. While maintaining this stirring state, it was kept at 40 ° C. for 5 hours. In this case, the amount of castor oil charged is adjusted so that the amount of the organic compound B relative to Ag is 1 equivalent.
得られた乾燥後のサンプルについてのＤＴＡ曲線を図４に示す。図１（置換前）と図４（置換後）の対比から、保護材は、アミンＡ（オレイルアミン）のほぼ全量が脱着し、有機化合物Ｂ（ひまし油成分）に置き換わったものと考えられる。
このサンプルについてのＤｘは６.０６ｎｍであり、ＤTEMは１０.９９ｎｍであった。ＤTEMの算出に使用した個々の粒子の粒子径は、最小値Ｄminが５.２２ｎｍ、最大値Ｄmaxが１５.２３ｎｍであり、この銀微粉のＣＶ値は１９.０％であった。
テキサノールおよびテルピネオールに対する分散性試験の結果、いずれに対しても良好な分散性が確認された。すなわち、保護材としてひまし油を付着させた銀ナノ粒子は、親水性と親油性の両方を兼ね備えた実用的な有機媒体に対して分散しやすいことがわかった。
The DTA curve for the obtained dried sample is shown in FIG. From the comparison between FIG. 1 (before substitution) and FIG. 4 (after substitution), it is considered that almost all the amine A (oleylamine) was desorbed and replaced with the organic compound B (castor oil component) in the protective material.
Dx for this sample was 6.06 nm and D TEM was 10.99 nm. Particle diameter of each particle used in computing D TEM, the minimum value D min is 5.22Nm, the maximum value D max is 15.23Nm, CV value of the silver micropowder was 19.0%.
As a result of the dispersibility test for texanol and terpineol, good dispersibility was confirmed for both. That is, it was found that silver nanoparticles to which castor oil was attached as a protective material were easily dispersed in a practical organic medium having both hydrophilicity and lipophilicity.
《実施例３》
有機化合物Ｂをコール酸（和光純薬株式会社製特級試薬、分子量１０７.９）に変えたことを除き、実施例１と同様の実験を行った。
すなわち、保護材置換工程において、コール酸３７.５８ｇと、イソプロパノール４００ｇを混合して、液温を４０℃に保ち、イソプロパノール中にコール酸を完全に溶解させた。この液４３７.５８ｇを、アミンＡ（オレイルアミン）に被覆された銀粒子が存在している前記洗浄後のスラリーに添加し、プロペラにて４００ｒｐｍで撹拌した。この撹拌状態を維持しながら４０℃で５時間保持した。この場合、Ａｇに対する有機化合物Ｂの量は０.１当量となるように有機化合物Ｂの仕込量を調製してある。
Example 3
The same experiment as in Example 1 was performed, except that the organic compound B was changed to cholic acid (special grade reagent manufactured by Wako Pure Chemical Industries, Ltd., molecular weight 107.9).
That is, in the protective material replacement step, 37.58 g of cholic acid and 400 g of isopropanol were mixed, the liquid temperature was kept at 40 ° C., and the cholic acid was completely dissolved in isopropanol. 437.58 g of this liquid was added to the washed slurry in which silver particles coated with amine A (oleylamine) were present, and the mixture was stirred with a propeller at 400 rpm. While maintaining this stirring state, it was kept at 40 ° C. for 5 hours. In this case, the amount of organic compound B prepared is adjusted so that the amount of organic compound B with respect to Ag is 0.1 equivalent.
得られた乾燥後のサンプルについてのＤＴＡ曲線を図５に示す。図１（置換前）と図５（置換後）の対比から、保護材は、アミンＡ（オレイルアミン）のほぼ全量が脱着し、有機化合物Ｂ（コール酸）に置き換わったものと考えられる。
このサンプルについてのＤｘは５.９０ｎｍであり、ＤTEMは９.０３ｎｍであった。ＤTEMの算出に使用した個々の粒子の粒子径は、最小値Ｄminが２.７５ｎｍ、最大値Ｄmaxが１６.７３ｎｍであり、この銀微粉のＣＶ値は２０.２％であった。
テキサノールおよびテルピネオールに対する分散性試験の結果、いずれに対しても良好な分散性が確認された。すなわち、保護材としてコール酸を付着させた銀ナノ粒子は、親水性と親油性の両方を兼ね備えた実用的な有機媒体に対して分散しやすいことがわかった。
The DTA curve for the obtained dried sample is shown in FIG. From the comparison between FIG. 1 (before substitution) and FIG. 5 (after substitution), it is considered that almost all the amine A (oleylamine) was desorbed and replaced with the organic compound B (cholic acid) in the protective material.
Dx for this sample was 5.90 nm and D TEM was 9.03 nm. Particle diameter of each particle used in computing D TEM, the minimum value D min is 2.75 nm, the maximum value D max is 16.73Nm, CV value of the silver micropowder was 20.2%.
As a result of the dispersibility test for texanol and terpineol, good dispersibility was confirmed for both. That is, it was found that silver nanoparticles having cholic acid attached as a protective material are easily dispersed in a practical organic medium having both hydrophilicity and lipophilicity.
《実施例４》
有機化合物Ｂをリシノール酸（和光純薬株式会社製特級試薬、分子量２８２.４５）に変えたことを除き、実施例１と同様の実験を行った。
すなわち、保護材置換工程において、リシノール酸２７６.６１ｇと、イソプロパノール４００ｇを混合して、液温を４０℃に保ち、イソプロパノール中にリシノール酸を完全に溶解させた。この液６７６.６１ｇを、アミンＡ（オレイルアミン）に被覆された銀粒子が存在している前記洗浄後のスラリーに添加し、プロペラにて４００ｒｐｍで撹拌した。この撹拌状態を維持しながら４０℃で５時間保持した。この場合、Ａｇに対する有機化合物Ｂの量は１当量となるように有機化合物Ｂの仕込量を調製してある。
Example 4
An experiment similar to Example 1 was performed, except that the organic compound B was changed to ricinoleic acid (special grade reagent manufactured by Wako Pure Chemical Industries, Ltd., molecular weight 282.45).
That is, in the protective material replacement step, 276.61 g of ricinoleic acid and 400 g of isopropanol were mixed, the liquid temperature was kept at 40 ° C., and ricinoleic acid was completely dissolved in isopropanol. 676.61 g of this solution was added to the washed slurry in which silver particles coated with amine A (oleylamine) were present, and the mixture was stirred with a propeller at 400 rpm. While maintaining this stirring state, it was kept at 40 ° C. for 5 hours. In this case, the amount of organic compound B prepared is adjusted so that the amount of organic compound B relative to Ag is 1 equivalent.
得られた乾燥後のサンプルについてのＤＴＡ曲線を図６に示す。図１（置換前）と図６（置換後）の対比から、保護材は、アミンＡ（オレイルアミン）のほぼ全量が脱着し、有機化合物Ｂ（リシノール酸）に置き換わったものと考えられる。
このサンプルについてのＤｘは６.０４ｎｍであり、ＤTEMは８.６０ｎｍであった。ＤTEMの算出に使用した個々の粒子の粒子径は、最小値Ｄminが５.４８ｎｍ、最大値Ｄmaxが１３.９６ｎｍであり、この銀微粉のＣＶ値は１５.６％であった。
テキサノールおよびテルピネオールに対する分散性試験の結果、いずれに対しても良好な分散性が確認された。すなわち、保護材としてリシノール酸を付着させた銀ナノ粒子は、親水性と親油性の両方を兼ね備えた実用的な有機媒体に対して分散しやすいことがわかった。
The DTA curve for the obtained sample after drying is shown in FIG. From the comparison between FIG. 1 (before substitution) and FIG. 6 (after substitution), it is considered that almost all the amine A (oleylamine) was desorbed and replaced with the organic compound B (ricinoleic acid).
The Dx for the sample is 6.04nm, D TEM was 8.60Nm. Particle diameter of each particle used in computing D TEM, the minimum value D min is 5.48Nm, the maximum value D max is 13.96Nm, CV value of the silver micropowder was 15.6%.
As a result of the dispersibility test for texanol and terpineol, good dispersibility was confirmed for both. That is, it was found that the silver nanoparticles having ricinoleic acid attached as a protective material are easily dispersed in a practical organic medium having both hydrophilicity and lipophilicity.
Claims (6)
（ａ）ＴＥＭ観察により測定される銀粒子の粒子径において、粒子径の標準偏差をσD、平均粒子径をＤTEMとするとき、「σD／ＤTEM×１００」の値をＣＶ値（％）とする。 Silver particles having an amine surface desorbing the amine and adsorbing salicylic acid on the surface X-ray crystal particle diameter Dx: 1 to 40 nm and CV value represented by (a) below: 40% or less A silver fine powder excellent in affinity with at least texanol and terpineol.
(A) In the particle diameter of silver particles measured by TEM observation, when the standard deviation of particle diameter is σ D and the average particle diameter is D TEM , the value of “σ D / D TEM × 100” is the CV value ( %).
（ａ）ＴＥＭ観察により測定される銀粒子の粒子径において、粒子径の標準偏差をσD、平均粒子径をＤTEMとするとき、「σD／ＤTEM×１００」の値をＣＶ値（％）とする。 Silver particles having an amine surface desorbed with the amine and adsorbed castor oil on the surface X-ray crystal particle diameter Dx: 1 to 40 nm and CV value represented by (a) below: 40% or less silver particles A silver fine powder excellent in affinity with at least texanol and terpineol.
(A) In the particle diameter of silver particles measured by TEM observation, when the standard deviation of particle diameter is σ D and the average particle diameter is D TEM , the value of “σ D / D TEM × 100” is the CV value ( %).
（ａ）ＴＥＭ観察により測定される銀粒子の粒子径において、粒子径の標準偏差をσD、平均粒子径をＤTEMとするとき、「σD／ＤTEM×１００」の値をＣＶ値（％）とする。 Silver particles having amine on the surface X-ray crystal particle diameter Dx formed by desorbing the amine and adsorbing cholic acid on the surface: CV value represented by (a): 40% or less Silver fine powder composed of particles and having excellent affinity for at least texanol and terpineol.
(A) In the particle diameter of silver particles measured by TEM observation, when the standard deviation of particle diameter is σ D and the average particle diameter is D TEM , the value of “σ D / D TEM × 100” is the CV value ( %).
（ａ）ＴＥＭ観察により測定される銀粒子の粒子径において、粒子径の標準偏差をσD、平均粒子径をＤTEMとするとき、「σD／ＤTEM×１００」の値をＣＶ値（％）とする。 Silver particles having amine on the surface X-ray crystal particle diameter Dx formed by desorbing the amine and adsorbing ricinoleic acid on the surface: 1 to 40 nm and CV value represented by (a) below: 40% or less silver Silver fine powder composed of particles and having excellent affinity for at least texanol and terpineol.
(A) In the particle diameter of silver particles measured by TEM observation, when the standard deviation of particle diameter is σ D and the average particle diameter is D TEM , the value of “σ D / D TEM × 100” is the CV value ( %).
（ａ）ＴＥＭ観察により測定される銀粒子の粒子径において、粒子径の標準偏差をσD、平均粒子径をＤTEMとするとき、「σD／ＤTEM×１００」の値をＣＶ値（％）とする。 X-ray crystal particle diameter Dx: 1 to 40 nm obtained by desorbing the amine of silver particles having amine on the surface and adsorbing an organic compound having at least one of salicylic acid, castor oil, cholic acid and ricinoleic acid on the surface CV value represented by (a): Silver ink in which 40% or less of silver particles are dispersed in texanol.
(A) In the particle diameter of silver particles measured by TEM observation, when the standard deviation of particle diameter is σ D and the average particle diameter is D TEM , the value of “σ D / D TEM × 100” is the CV value ( %).
（ａ）ＴＥＭ観察により測定される銀粒子の粒子径において、粒子径の標準偏差をσD、平均粒子径をＤTEMとするとき、「σD／ＤTEM×１００」の値をＣＶ値（％）とする。 X-ray crystal particle diameter Dx: 1 to 40 nm obtained by desorbing the amine of silver particles having amine on the surface and adsorbing an organic compound having at least one of salicylic acid, castor oil, cholic acid and ricinoleic acid on the surface CV value represented by (a): Silver ink in which silver particles of 40% or less are dispersed in terpineol.
(A) In the particle diameter of silver particles measured by TEM observation, when the standard deviation of particle diameter is σ D and the average particle diameter is D TEM , the value of “σ D / D TEM × 100” is the CV value ( %).
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| KR20170042618A (en) | 2014-07-31 | 2017-04-19 | 도와 일렉트로닉스 가부시키가이샤 | Silver Powder, Method for Producing Same, and Conductive Paste |
| CN107614164A (en) * | 2015-06-15 | 2018-01-19 | 株式会社大阪曹达 | Metallic nano-particle manufacture composition |
| US9993871B2 (en) | 2014-07-31 | 2018-06-12 | Dowa Electronics Materials Co., Ltd. | Silver powder, method for producing same, and conductive paste |
| WO2018180048A1 (en) * | 2017-03-29 | 2018-10-04 | 住友金属鉱山株式会社 | Electroconductive paste |
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