JP2014173092A - Nickel nanoparticles, method for manufacturing the same, and nickel paste - Google Patents
Nickel nanoparticles, method for manufacturing the same, and nickel paste Download PDFInfo
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- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 title claims abstract description 332
- 229910052759 nickel Inorganic materials 0.000 title claims abstract description 164
- 239000002105 nanoparticle Substances 0.000 title claims abstract description 123
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 59
- 238000000034 method Methods 0.000 title claims abstract description 25
- PKPDMQHIYXYXTQ-UHFFFAOYSA-N [Ni].NN Chemical compound [Ni].NN PKPDMQHIYXYXTQ-UHFFFAOYSA-N 0.000 claims abstract description 92
- OAKJQQAXSVQMHS-UHFFFAOYSA-N hydrazine Substances NN OAKJQQAXSVQMHS-UHFFFAOYSA-N 0.000 claims abstract description 56
- 239000002904 solvent Substances 0.000 claims abstract description 37
- 238000005406 washing Methods 0.000 claims abstract description 35
- 239000011164 primary particle Substances 0.000 claims abstract description 21
- 239000003513 alkali Substances 0.000 claims abstract description 13
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 12
- 150000002816 nickel compounds Chemical class 0.000 claims abstract description 6
- -1 hydrazine compound Chemical class 0.000 claims abstract description 5
- 239000002245 particle Substances 0.000 claims description 53
- 238000004220 aggregation Methods 0.000 claims description 37
- 230000002776 aggregation Effects 0.000 claims description 36
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 31
- 229920002873 Polyethylenimine Polymers 0.000 claims description 26
- 239000003112 inhibitor Substances 0.000 claims description 25
- 239000007788 liquid Substances 0.000 claims description 22
- 239000011163 secondary particle Substances 0.000 claims description 14
- 238000004140 cleaning Methods 0.000 claims description 13
- 238000001035 drying Methods 0.000 claims description 13
- 238000009826 distribution Methods 0.000 claims description 10
- 238000000926 separation method Methods 0.000 claims description 10
- 230000002744 anti-aggregatory effect Effects 0.000 claims description 8
- 238000002296 dynamic light scattering Methods 0.000 claims description 6
- 238000005259 measurement Methods 0.000 claims description 6
- 230000033116 oxidation-reduction process Effects 0.000 claims description 6
- 238000001000 micrograph Methods 0.000 claims description 4
- 239000008213 purified water Substances 0.000 claims description 2
- 230000002265 prevention Effects 0.000 claims 1
- 239000007787 solid Substances 0.000 abstract description 30
- 239000000843 powder Substances 0.000 abstract description 5
- 239000012808 vapor phase Substances 0.000 abstract description 2
- 239000000203 mixture Substances 0.000 abstract 1
- 230000000052 comparative effect Effects 0.000 description 30
- 239000006185 dispersion Substances 0.000 description 23
- 239000000243 solution Substances 0.000 description 19
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 15
- 239000007864 aqueous solution Substances 0.000 description 15
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 12
- 150000002815 nickel Chemical class 0.000 description 9
- 238000003756 stirring Methods 0.000 description 9
- 239000000126 substance Substances 0.000 description 9
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 8
- 239000007789 gas Substances 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 6
- IKDUDTNKRLTJSI-UHFFFAOYSA-N hydrazine hydrate Chemical compound O.NN IKDUDTNKRLTJSI-UHFFFAOYSA-N 0.000 description 6
- 239000012299 nitrogen atmosphere Substances 0.000 description 6
- 229920000036 polyvinylpyrrolidone Polymers 0.000 description 6
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 description 6
- LZZYPRNAOMGNLH-UHFFFAOYSA-M Cetrimonium bromide Chemical compound [Br-].CCCCCCCCCCCCCCCC[N+](C)(C)C LZZYPRNAOMGNLH-UHFFFAOYSA-M 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 4
- 238000000354 decomposition reaction Methods 0.000 description 4
- 239000003960 organic solvent Substances 0.000 description 4
- 239000011148 porous material Substances 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- 230000009467 reduction Effects 0.000 description 4
- 239000011343 solid material Substances 0.000 description 4
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 239000012298 atmosphere Substances 0.000 description 3
- 238000011156 evaluation Methods 0.000 description 3
- 239000011261 inert gas Substances 0.000 description 3
- 239000004810 polytetrafluoroethylene Substances 0.000 description 3
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 3
- 238000004062 sedimentation Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 238000009210 therapy by ultrasound Methods 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- 229910021586 Nickel(II) chloride Inorganic materials 0.000 description 2
- 230000032683 aging Effects 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- ZBCBWPMODOFKDW-UHFFFAOYSA-N diethanolamine Chemical compound OCCNCCO ZBCBWPMODOFKDW-UHFFFAOYSA-N 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000000976 ink Substances 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- QMMRZOWCJAIUJA-UHFFFAOYSA-L nickel dichloride Chemical compound Cl[Ni]Cl QMMRZOWCJAIUJA-UHFFFAOYSA-L 0.000 description 2
- LGQLOGILCSXPEA-UHFFFAOYSA-L nickel sulfate Chemical compound [Ni+2].[O-]S([O-])(=O)=O LGQLOGILCSXPEA-UHFFFAOYSA-L 0.000 description 2
- 229910000363 nickel(II) sulfate Inorganic materials 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- 238000006116 polymerization reaction Methods 0.000 description 2
- 238000011085 pressure filtration Methods 0.000 description 2
- 239000003223 protective agent Substances 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 238000000967 suction filtration Methods 0.000 description 2
- 239000006228 supernatant Substances 0.000 description 2
- 239000000725 suspension Substances 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 238000001291 vacuum drying Methods 0.000 description 2
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical compound [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 description 1
- 239000001856 Ethyl cellulose Substances 0.000 description 1
- ZZSNKZQZMQGXPY-UHFFFAOYSA-N Ethyl cellulose Chemical compound CCOCC1OC(OC)C(OCC)C(OCC)C1OC1C(O)C(O)C(OC)C(CO)O1 ZZSNKZQZMQGXPY-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 239000002879 Lewis base Substances 0.000 description 1
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 1
- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical compound [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 description 1
- MQRWBMAEBQOWAF-UHFFFAOYSA-N acetic acid;nickel Chemical compound [Ni].CC(O)=O.CC(O)=O MQRWBMAEBQOWAF-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- WUOACPNHFRMFPN-UHFFFAOYSA-N alpha-terpineol Chemical compound CC1=CCC(C(C)(C)O)CC1 WUOACPNHFRMFPN-UHFFFAOYSA-N 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- BIVUUOPIAYRCAP-UHFFFAOYSA-N aminoazanium;chloride Chemical compound Cl.NN BIVUUOPIAYRCAP-UHFFFAOYSA-N 0.000 description 1
- 239000003006 anti-agglomeration agent Substances 0.000 description 1
- GDTBXPJZTBHREO-UHFFFAOYSA-N bromine Substances BrBr GDTBXPJZTBHREO-UHFFFAOYSA-N 0.000 description 1
- 229910052794 bromium Inorganic materials 0.000 description 1
- 239000001768 carboxy methyl cellulose Substances 0.000 description 1
- 239000003985 ceramic capacitor Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000006837 decompression Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- SQIFACVGCPWBQZ-UHFFFAOYSA-N delta-terpineol Natural products CC(C)(O)C1CCC(=C)CC1 SQIFACVGCPWBQZ-UHFFFAOYSA-N 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 229920001249 ethyl cellulose Polymers 0.000 description 1
- 235000019325 ethyl cellulose Nutrition 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000005187 foaming Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 150000007527 lewis bases Chemical class 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 239000012046 mixed solvent Substances 0.000 description 1
- 229940078494 nickel acetate Drugs 0.000 description 1
- LAIZPRYFQUWUBN-UHFFFAOYSA-L nickel chloride hexahydrate Chemical compound O.O.O.O.O.O.[Cl-].[Cl-].[Ni+2] LAIZPRYFQUWUBN-UHFFFAOYSA-L 0.000 description 1
- SMAMDWMLHWVJQM-UHFFFAOYSA-L nickel(2+);diformate;dihydrate Chemical compound O.O.[Ni+2].[O-]C=O.[O-]C=O SMAMDWMLHWVJQM-UHFFFAOYSA-L 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 229920000083 poly(allylamine) Polymers 0.000 description 1
- 239000001267 polyvinylpyrrolidone Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 239000013049 sediment Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 description 1
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 description 1
- 229940116411 terpineol Drugs 0.000 description 1
- 230000008719 thickening Effects 0.000 description 1
- 239000011882 ultra-fine particle Substances 0.000 description 1
- 238000001132 ultrasonic dispersion Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
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- Manufacture Of Metal Powder And Suspensions Thereof (AREA)
- Powder Metallurgy (AREA)
- Conductive Materials (AREA)
- Non-Insulated Conductors (AREA)
Abstract
Description
本発明は、主にエレクトロニクスの分野において使用されるニッケルナノ粒子とその製造方法、およびニッケルペーストに関する。 The present invention relates to nickel nanoparticles mainly used in the field of electronics, a method for producing the same, and nickel paste.
近年、エレクトロニクスの分野では電子機器の小型化・高性能化に伴い、使用される金属材料も微小化が求められている。例えば、積層セラミックコンデンサーの内部電極層に使用されているニッケル粒子の粒径は、現状では２００〜４００ｎｍ程度であるが、内部電極層の薄膜化に伴ってより微小化し、将来的には粒径が１００ｎｍ以下のニッケル粒子が使用されると考えられる。
従来の技術において、粒径１００ｎｍ以下のニッケル粒子については、以下のような製造方法が提案されている。
In recent years, in the field of electronics, with the miniaturization and high performance of electronic devices, metal materials used are also required to be miniaturized. For example, the particle size of nickel particles used for the internal electrode layer of the multilayer ceramic capacitor is about 200 to 400 nm at present, but the particle size becomes smaller as the internal electrode layer becomes thinner, and in the future the particle size It is considered that nickel particles having a diameter of 100 nm or less are used.
In the prior art, the following manufacturing methods have been proposed for nickel particles having a particle size of 100 nm or less.
特許文献１には、ニッケル塩を高温で気化させた後、当該気化したニッケル塩を気相中においてＨ２ガスにより還元する方法が記載されている。そして、平均粒径５０〜３００ｎｍの一次粒子が得られた旨の記載がある。 Patent Document 1 describes a method in which a nickel salt is vaporized at a high temperature and then the vaporized nickel salt is reduced with H 2 gas in a gas phase. There is a description that primary particles having an average particle diameter of 50 to 300 nm were obtained.
特許文献２には、水、エタノール、トルエンなどのエマルジョン液相中に、ニッケル塩とポリビニルピロリドン（以下「ＰＶＰ」と記載する場合がある。）などの保護剤・添加剤と呼ばれる物質を添加した後、ヒドラジンを添加してニッケル−ヒドラジン錯体を生成させ、この錯体を含む溶液にＮａＢＨ４を添加し、錯体を還元させることで、ポリマー保護ニッケル超微粒子を作製する方法が記載されている。そして、平均粒子径１００ｎｍ以下のニッケル微粒子が得られた旨の記載がある。 In Patent Document 2, a substance called a protective agent / additive such as a nickel salt and polyvinylpyrrolidone (hereinafter sometimes referred to as “PVP”) is added to an emulsion liquid phase such as water, ethanol, and toluene. Thereafter, a method is described in which hydrazine is added to form a nickel-hydrazine complex, NaBH 4 is added to a solution containing the complex, and the complex is reduced to produce polymer-protected nickel ultrafine particles. There is a description that nickel fine particles having an average particle diameter of 100 nm or less were obtained.
特許文献３には、ギ酸ニッケル二水和物と、脂肪族アミンなどのルイス塩基、および溶媒とを含む溶液を加熱することにより、微粒子ニッケル粉を作製する方法が記載されている。そして、平均粒子径１００ｎｍ以下で、かつ、粒子径の分布の狭い均一なニッケル粒子が得られた旨の記載がある。 Patent Document 3 describes a method of producing fine nickel powder by heating a solution containing nickel formate dihydrate, a Lewis base such as an aliphatic amine, and a solvent. There is a description that uniform nickel particles having an average particle size of 100 nm or less and a narrow particle size distribution were obtained.
しかしながら、本発明者らの検討によれば、特許文献１に記載の方法は、気相法による製造法であるため、特別な製造装置が必要となり製造コストが高くなるという問題がある。さらに、気相法による製造方法においては１,０００℃以上の高温条件による還元工程があるため、粒径は１００ｎｍ以上になりやすく、粒径１００ｎｍ以下の粒子を得る為には分級工程が必須である。この為、粒径１００ｎｍ以下の粒子製造においては、歩留まりが非常に悪くなり不向きである。 However, according to the study by the present inventors, the method described in Patent Document 1 is a manufacturing method by a gas phase method, and thus there is a problem that a special manufacturing apparatus is required and the manufacturing cost increases. Furthermore, in the production method by the vapor phase method, since there is a reduction step under a high temperature condition of 1,000 ° C. or higher, the particle size tends to be 100 nm or more. is there. For this reason, in the production of particles having a particle size of 100 nm or less, the yield is very poor and is not suitable.
また、特許文献２に記載の方法は、ニッケル−ヒドラジン錯体からニッケル粉を作成するものである。そして、製造するニッケル粒子の粒径を制御するため、保護剤または分散剤としてＰＶＰや、セチルトリメチルアンモニウムブロマイド（以下「ＣＴＡＢ」と記載する場合がある。）、ナトリウムカルボキシメチルセルロース（以下「Ｎａ−ＣＭＣ」と記載する場合がある。）などの物質を使用することが必須である。そして当該必須の物質の使用に起因して、製造された粒子には３〜１０質量％程度の当該必須の物質が付着している。 Moreover, the method of patent document 2 produces nickel powder from a nickel-hydrazine complex. In order to control the particle diameter of the nickel particles to be produced, PVP, cetyltrimethylammonium bromide (hereinafter sometimes referred to as “CTAB”), sodium carboxymethylcellulose (hereinafter referred to as “Na-CMC”) as a protective agent or dispersant. It is essential to use substances such as Due to the use of the essential substance, about 3 to 10% by mass of the essential substance is adhered to the manufactured particles.
ここで、製造された粒子に３〜１０質量％程度のＰＶＰが付着している場合、当該ＰＶＰは重合度が高く、ニッケル粒子へ多量に被着してしまう。この多量のＰＶＰ付着のために、製造した粒子をペーストやインクの原料として使用する際、焼成時に分解による体積収縮が大きくなるという問題がある。 Here, when 3-10 mass% PVP adheres to the manufactured particle | grains, the said PVP has a high polymerization degree, and will adhere to nickel particles in large quantities. Due to this large amount of PVP adhesion, when the produced particles are used as a raw material for pastes and inks, there is a problem that volume shrinkage due to decomposition increases during firing.
また、製造された粒子に３〜１０質量％程度のＣＴＡＢが付着している場合、当該ＣＴＡＢには臭素が含まれており、これが粒子製造段階で粒子内部に混入する可能性が高くなり、導電性低下の原因になるという問題がある。 In addition, when about 3 to 10% by mass of CTAB adheres to the produced particles, the CTAB contains bromine, which is likely to be mixed into the particles at the particle production stage, and thus conductive. There is a problem that it causes a decline in sex.
また、製造された粒子に３〜１０質量％程度のＮａ−ＣＭＣが付着している場合、当該Ｎａ−ＣＭＣにはナトリウムが含まれており、上記ＣＴＡＢと同様に、導電性低下の原因となるという問題がある。さらに、Ｎａ−ＣＭＣの重合度が高いために、添加により溶媒が増粘してしまい、均一な攪拌がし難くなると同時に、発泡による攪拌阻害の問題も起こってしまう。 Moreover, when about 3-10 mass% Na-CMC has adhered to the manufactured particle | grains, the said Na-CMC contains sodium, and it becomes a cause of electroconductivity fall like said CTAB. There is a problem. Further, since the degree of polymerization of Na-CMC is high, the addition of the solvent increases the viscosity, making uniform stirring difficult, and at the same time causing the problem of stirring inhibition due to foaming.
また、特許文献３に記載の方法においては、水に不溶な脂肪族アミンを使用しているため、製造方法が有機溶媒中に限定されてしまい、廃液処理も含め製造コストが割高となってしまう。さらに、反応温度の制御方法として、マイクロ波の照射を行うため、バッチアップ製造が出来にくく、生産性が低い製造方法となっている。 Further, in the method described in Patent Document 3, since an aliphatic amine insoluble in water is used, the production method is limited to an organic solvent, and the production cost including waste liquid treatment becomes expensive. . Furthermore, as a method for controlling the reaction temperature, since microwave irradiation is performed, it is difficult to perform batch-up production and the production method is low.
本発明は、上述の状況の下で為されたものであり、その解決しようとする課題は、一次粒子径が１００ｎｍ以下であり、かつ二次凝集の少ない分散性の良好なニッケルナノ粒子粉、および、当該ニッケルナノ粒子粉を、低コストで高い生産性を保ちながら製造出来る、ニッケルナノ粒子とその製造方法、および当該ニッケルナノ粒子を用いたニッケルペーストを提供することである。 The present invention has been made under the circumstances described above, and the problem to be solved is a nickel nanoparticle powder having a primary particle diameter of 100 nm or less and a low dispersibility and good dispersibility. And it is providing the nickel paste using the said nickel nanoparticle and its manufacturing method which can manufacture the said nickel nanoparticle powder, maintaining high productivity at low cost, and the said nickel nanoparticle.
上述の課題を解決する為、本発明者等は研究を重ねた結果、走査型電子顕微鏡画像から算出した一次粒子径が１００ｎｍ以下であり、動的光散乱粒度分布測定により測定される二次粒子径が２００ｎｍ以下に分散しているニッケルナノ粒子であって、その表面が凝集防止剤によって被覆されているニッケルナノ粒子に想到した。そして、まずニッケル化合物とヒドラジン化合物とからニッケル−ヒドラジン錯体を製造し、製造された錯体を固液分離して錯体を洗浄して、清浄なニッケル−ヒドラジン錯体を得る。得られた当該清浄なニッケル−ヒドラジン錯体を、凝集防止剤を含む溶液中に添加し、さらにアルカリ溶液を添加することによって、当該ニッケルナノ粒子を製造する製造方法に想到し、本発明を完成した。 In order to solve the above-mentioned problems, the present inventors have conducted research, and as a result, the primary particle diameter calculated from the scanning electron microscope image is 100 nm or less, and secondary particles measured by dynamic light scattering particle size distribution measurement. The inventors have conceived nickel nanoparticles having a diameter of 200 nm or less, the surfaces of which are coated with an aggregation inhibitor. First, a nickel-hydrazine complex is produced from a nickel compound and a hydrazine compound, the produced complex is subjected to solid-liquid separation, and the complex is washed to obtain a clean nickel-hydrazine complex. The resulting clean nickel-hydrazine complex was added to a solution containing an anti-aggregation agent, and an alkaline solution was further added to conceive a production method for producing the nickel nanoparticles, thereby completing the present invention. .
即ち、上述の課題を解決するための第１の発明は、
ニッケル化合物溶液とヒドラジン化合物溶液とから、ニッケル−ヒドラジン錯体溶液を生成する工程と、
前記生成したニッケル−ヒドラジン錯体溶液を固液分離し、ニッケル−ヒドラジン錯体を得る工程と、
前記得られたニッケル−ヒドラジン錯体を洗浄し、洗浄されたニッケル−ヒドラジン錯体を得る工程と、
前記洗浄されたニッケル−ヒドラジン錯体と、凝集防止剤と、アルカリとを、溶媒へ添加してニッケルナノ粒子を製造する工程とを有することを特徴とするニッケルナノ粒子の製造方法である。
第２の発明は、
前記ニッケル−ヒドラジン錯体を洗浄する工程において、
洗浄液として純水を用い、当該洗浄液を、ニッケル−ヒドラジン錯体を通過させることで洗浄を行い、当該洗浄後における洗浄液の酸化還元電位が−７００ｍＶ以上となるまで洗浄を継続することを特徴とする第１の発明に記載のニッケルナノ粒子の製造方法である。
第３の発明は、
前記ニッケル−ヒドラジン錯体を洗浄する工程の後、洗浄されたニッケル−ヒドラジン錯体の含有する水分量が２質量％以下になるまで乾燥させることを特徴とする、第１または第２の発明のいずれかに記載のニッケルナノ粒子の製造方法である。
第４の発明は、
前記凝集防止剤としてポリエチレンイミンを用いることを特徴とする第１から第３の発明のいずれかに記載のニッケルナノ粒子の製造方法である。
第５の発明は、
前記ポリエチレンイミンの平均分子量が２００００以下であることを特徴とする第４の発明に記載のニッケルナノ粒子の製造方法である。
第６の発明は、
前記ポリエチレンイミンの平均分子量が２０００以下であることを特徴とする第４の発明に記載のニッケルナノ粒子の製造方法である。
第７の発明は、
表面が凝集防止剤によって被覆され、走査型電子顕微鏡画像から算出した一次粒子径が１００ｎｍ以下であり、動的光散乱粒度分布測定により測定される二次粒子径が２００ｎｍ以下であることを特徴とするニッケルナノ粒子である。
第８の発明は、
前記凝集防止剤がポリエチレンイミンであることを特徴とする第７の発明に記載のニッケルナノ粒子である。
第９の発明は、
前記ポリエチレンイミンの平均分子量が２００００以下であることを特徴とする第８の発明に記載のニッケルナノ粒子である。
第１０の発明は、
前記ポリエチレンイミンの平均分子量が２０００以下であることを特徴とする第８の発明に記載のニッケルナノ粒子である。
第１１の発明は、
第７から第１０の発明のいずれかに記載のニッケルナノ粒子を含むことを特徴とするニッケルペーストである。
That is, the first invention for solving the above-described problem is
Producing a nickel-hydrazine complex solution from the nickel compound solution and the hydrazine compound solution;
Solid-liquid separation of the produced nickel-hydrazine complex solution to obtain a nickel-hydrazine complex;
Washing the obtained nickel-hydrazine complex to obtain a washed nickel-hydrazine complex;
A method for producing nickel nanoparticles comprising the step of producing nickel nanoparticles by adding the washed nickel-hydrazine complex, an aggregation inhibitor and an alkali to a solvent.
The second invention is
In the step of washing the nickel-hydrazine complex,
Purified water is used as a cleaning liquid, the cleaning liquid is cleaned by passing a nickel-hydrazine complex, and the cleaning is continued until the oxidation-reduction potential of the cleaning liquid after the cleaning becomes −700 mV or more. It is a manufacturing method of the nickel nanoparticle as described in 1 invention.
The third invention is
Either the first or second invention, wherein after the step of washing the nickel-hydrazine complex, drying is performed until the water content of the washed nickel-hydrazine complex is 2% by mass or less. It is the manufacturing method of the nickel nanoparticle as described in above.
The fourth invention is:
The method for producing nickel nanoparticles according to any one of the first to third inventions, wherein polyethyleneimine is used as the aggregation inhibitor.
The fifth invention is:
The average molecular weight of the polyethyleneimine is 20000 or less. The method for producing nickel nanoparticles according to the fourth invention.
The sixth invention is:
The average molecular weight of the polyethyleneimine is 2000 or less, and the method for producing nickel nanoparticles according to the fourth invention.
The seventh invention
The surface is coated with an anti-aggregation agent, the primary particle size calculated from a scanning electron microscope image is 100 nm or less, and the secondary particle size measured by dynamic light scattering particle size distribution measurement is 200 nm or less. Nickel nanoparticles.
The eighth invention
The nickel nanoparticle according to the seventh invention, wherein the anti-aggregation agent is polyethyleneimine.
The ninth invention
Nickel nanoparticles according to the eighth invention, wherein the polyethyleneimine has an average molecular weight of 20000 or less.
The tenth invention is
Nickel nanoparticles according to the eighth invention, wherein the polyethyleneimine has an average molecular weight of 2000 or less.
The eleventh invention is
A nickel paste comprising the nickel nanoparticles according to any one of the seventh to tenth inventions.
本発明に係るニッケルナノ粒子は、一次粒子径が１００ｎｍ以下であり、かつ二次凝集の少ない分散性の良好なニッケルナノ粒子で、小型化、高性能化されたエレクトロニクス用途のニッケルペーストに適した性状・特性を有していた。また、本発明に係るニッケルナノ粒子の製造方法によれば、一次粒子径が１００ｎｍ以下でありながら、有機溶媒中での分散性を維持したニッケルナノ粒子粉を低コストで高い生産性を保ちながら製造することが出来た。 The nickel nanoparticle according to the present invention is a nickel nanoparticle having a primary particle diameter of 100 nm or less and a low dispersibility and good dispersibility, and suitable for a nickel paste for electronic use that has been downsized and improved in performance. It had properties and characteristics. In addition, according to the method for producing nickel nanoparticles according to the present invention, while maintaining the high productivity at low cost, the nickel nanoparticle powder that maintains dispersibility in an organic solvent while the primary particle diameter is 100 nm or less. I was able to manufacture it.
以下、まず本発明に係るニッケルナノ粒子の製造方法について説明し、次に、本発明に係るニッケルナノ粒子の性状・特性について説明する。
本発明に係るニッケルナノ粒子の製造方法は、ニッケル−ヒドラジン錯体の製造工程、ニッケル−ヒドラジン錯体の分離工程、ニッケル−ヒドラジン錯体の洗浄工程、ニッケル−ヒドラジン錯体の乾燥工程、凝集防止剤の溶解工程、ニッケル−ヒドラジン錯体の再分散工程、ニッケルナノ粒子の製造工程を有する。まず、当該各製造工程について説明する。
Hereinafter, the method for producing nickel nanoparticles according to the present invention will be described first, and then the properties and characteristics of the nickel nanoparticles according to the present invention will be described.
The method for producing nickel nanoparticles according to the present invention includes a nickel-hydrazine complex production process, a nickel-hydrazine complex separation process, a nickel-hydrazine complex washing process, a nickel-hydrazine complex drying process, and an aggregation inhibitor dissolving process. A re-dispersing step of the nickel-hydrazine complex and a manufacturing step of the nickel nanoparticles. First, each manufacturing process will be described.
（ニッケル−ヒドラジン錯体の製造工程）
ニッケル−ヒドラジン錯体を製造する工程である。
まず、ニッケル塩の水溶液を準備する。ニッケル塩としては、塩化ニッケル、硫酸ニッケル、酢酸ニッケルなどから選択される１種類以上用いることが出来るが、原料コストや作業性の観点から塩化ニッケルまたは硫酸ニッケルが好ましい。
ニッケル塩水溶液の濃度は、０．１〜３．０モル／Ｌが好ましい。０．１モル／Ｌ以上であれば生産性が良く、３．０モル／Ｌ以下であれば、製造したニッケル−ヒドラジン錯体の凝集が回避出来る。
(Nickel-hydrazine complex production process)
This is a process for producing a nickel-hydrazine complex.
First, an aqueous solution of nickel salt is prepared. As the nickel salt, one or more selected from nickel chloride, nickel sulfate, nickel acetate and the like can be used, but nickel chloride or nickel sulfate is preferred from the viewpoint of raw material cost and workability.
The concentration of the nickel salt aqueous solution is preferably 0.1 to 3.0 mol / L. If it is 0.1 mol / L or more, productivity is good, and if it is 3.0 mol / L or less, aggregation of the manufactured nickel-hydrazine complex can be avoided.
一方、ニッケル−ヒドラジン錯体形成の為の溶媒を準備する。
溶媒として、濃度が４０〜８０質量％のヒドラジン水溶液を準備する。ヒドラジン水溶液の濃度が４０質量％以上であれば反応が効率良く進行し、８０質量％以下であれば操作上の安全面から好ましいからである。
ヒドラジン原料としては、ヒドラジン、ヒドラジン一水和物（８０質量％）、ヒドラジン塩化物を用いることが出来るが、安全面の観点からヒドラジン一水和物が好ましい。
溶媒へのヒドラジンの添加量は、当該ヒドラジン水溶液に添加されるニッケル１モルに対して、当量を超えた過剰量である２．０〜１２モル、好ましくは２．５〜１２モル、さらに好ましくは２．５〜６．０モルとする。当該ヒドラジン水溶液中に、ニッケル１モルに対してヒドラジンが２．０モル以上であれば、未反応のニッケルが生ぜず、ヒドラジンが１２モル以下であれば添加効率が保てるからである。
準備したニッケル塩の水溶液を、大気下、Ｎ２、Ａｒなどの不活性ガス雰囲気下、好ましくはＮ２雰囲気下に置き、撹拌羽根を用いて７００ｒｐｍ以下で撹拌しながら２０〜６０℃、好ましくは４０℃〜６０℃に加温する。
On the other hand, a solvent for forming a nickel-hydrazine complex is prepared.
A hydrazine aqueous solution having a concentration of 40 to 80% by mass is prepared as a solvent. This is because the reaction proceeds efficiently when the concentration of the hydrazine aqueous solution is 40% by mass or more, and preferably 80% by mass or less from the viewpoint of operational safety.
As the hydrazine raw material, hydrazine, hydrazine monohydrate (80% by mass), and hydrazine chloride can be used, but hydrazine monohydrate is preferable from the viewpoint of safety.
The amount of hydrazine added to the solvent is 2.0 to 12 mol, preferably 2.5 to 12 mol, more preferably an excess amount exceeding the equivalent, relative to 1 mol of nickel added to the aqueous hydrazine solution. The amount is set to 2.5 to 6.0 mol. This is because in the hydrazine aqueous solution, if hydrazine is 2.0 mol or more with respect to 1 mol of nickel, unreacted nickel is not generated, and if hydrazine is 12 mol or less, the addition efficiency can be maintained.
The prepared aqueous solution of nickel salt is placed in an atmosphere of an inert gas such as N 2 or Ar, preferably in an N 2 atmosphere, preferably 20 to 60 ° C. while stirring at 700 rpm or less using a stirring blade, preferably Warm to 40-60 ° C.
前記加温された溶媒へ、前記調温されたヒドラジン水溶液を添加する際、生成するニッケル−ヒドラジン錯体が凝集するのを回避する為、一挙に添加するのではなく、１ｇ／ｍｉｎ程度の添加速度で連続添加することが好ましい。尚、上述したように、当該添加方法としては、ニッケル塩水溶液にヒドラジン水溶液を連続添加する方法が好ましいが、ヒドラジン水溶液へニッケル塩水溶液を連続添加することも出来る。
当該添加中のヒドラジン水溶液の液温は２０〜６０℃、好ましくは２０〜３０℃とする。
生成するニッケル−ヒドラジン錯体は［Ｎｉ（Ｎ２Ｈ４）３］Ｃｌ２、［Ｎｉ（Ｎ２Ｈ４）２］Ｃｌ２と考えられる。ニッケル−ヒドラジン錯体の一次形状は殆ど球状となるが、楕円状、針状であってもよい。ニッケル−ヒドラジン錯体の二次凝集径は１μｍ以下とすることが好ましい。
When adding the temperature-controlled hydrazine aqueous solution to the heated solvent, the addition rate of about 1 g / min is used instead of adding all at once to avoid aggregation of the nickel-hydrazine complex formed. It is preferable to add continuously. As described above, the addition method is preferably a method of continuously adding a hydrazine aqueous solution to a nickel salt aqueous solution, but a nickel salt aqueous solution can also be continuously added to a hydrazine aqueous solution.
The liquid temperature of the aqueous hydrazine solution during the addition is 20 to 60 ° C, preferably 20 to 30 ° C.
The produced nickel-hydrazine complex is considered to be [Ni (N 2 H 4 ) 3 ] Cl 2 , [Ni (N 2 H 4 ) 2 ] Cl 2 . The primary shape of the nickel-hydrazine complex is almost spherical, but may be elliptical or needle-like. The secondary aggregation diameter of the nickel-hydrazine complex is preferably 1 μm or less.
（ニッケル−ヒドラジン錯体の分離工程）
製造したニッケル−ヒドラジン錯体を、溶液から固液分離する。
具体的には、生成したニッケル−ヒドラジン錯体を、加圧ろ過、吸引ろ過、フィルタープレス等（但し、孔径が１μｍ以下であることが好ましい。）を用いて溶液から分離する。この際、分離された固形物（ニッケル−ヒドラジン錯体）に厚みがあることが望ましい。これは、後述する洗浄工程において通水洗浄する際に、短時間でも固形物に保水させ、未反応であった遊離のヒドラジンを分散、分離するためである。例えば、当該厚みの最も薄い箇所でも１ｍｍ以上、最も厚い箇所でも３０ｍｍ以下となるように分離装置の設定、または、ニッケル−ヒドラジン錯体量を調整することが好ましい。この結果、後工程のニッケル−ヒドラジン錯体の洗浄工程において、固形物における保水性と通水性とのバランスを図ることとなり、当該固形物内部の未反応であった遊離のヒドラジンの残留を除去することができるからである。
(Nickel-hydrazine complex separation step)
The produced nickel-hydrazine complex is solid-liquid separated from the solution.
Specifically, the produced nickel-hydrazine complex is separated from the solution using pressure filtration, suction filtration, filter press, etc. (however, the pore diameter is preferably 1 μm or less). At this time, it is desirable that the separated solid (nickel-hydrazine complex) has a thickness. This is because, when washing with water in a washing step described later, water is retained in the solid matter even for a short time, and unreacted free hydrazine is dispersed and separated. For example, it is preferable to adjust the setting of the separation apparatus or the amount of the nickel-hydrazine complex so that the thickness is 1 mm or more at the thinnest portion and 30 mm or less at the thickest portion. As a result, in the subsequent step of washing the nickel-hydrazine complex, the balance of water retention and water permeability in the solid material will be achieved, and the residual unreacted hydrazine in the solid material will be removed. Because you can.
（ニッケル−ヒドラジン錯体の洗浄工程）
固液分離した固形物（ニッケル−ヒドラジン錯体）を洗浄し未反応であった遊離のヒドラジン（本発明において「未反応ヒドラジン」と記載する場合もある。）を除去する。これは、当該工程において固形物内部の未反応であった遊離のヒドラジンを除去することにより、後工程である「ニッケルナノ粒子の製造工程」において、容易且つ良好にニッケルナノ粒子が生成するからである。
具体的な洗浄方法としては、上記固液分離して得られた１ｍｍ〜３０ｍｍの厚みを有する固形物へ、洗浄溶媒を通過させることで洗浄するのが好ましい。洗浄溶媒には純水、エタノール、２−プロパノール、アセトン、またはこれらの混合溶媒を用いることができるが、コスト、生産性の観点から純水が最も好ましい。
このように固形物（ニッケル−ヒドラジン錯体）を定置し、通水することで固形物内にある未反応のヒドラジンを好適に洗い出すことができる。
(Nickel-hydrazine complex washing process)
The solid substance (nickel-hydrazine complex) separated by solid-liquid separation is washed to remove free hydrazine that may be unreacted (in some cases, it may be referred to as “unreacted hydrazine” in the present invention). This is because nickel nanoparticles are easily and satisfactorily produced in the “nickel nanoparticle production process”, which is a subsequent process, by removing the unreacted free hydrazine in the solid in the process. is there.
As a specific washing method, washing is preferably performed by passing a washing solvent through a solid material having a thickness of 1 mm to 30 mm obtained by solid-liquid separation. As the washing solvent, pure water, ethanol, 2-propanol, acetone, or a mixed solvent thereof can be used, but pure water is most preferable from the viewpoint of cost and productivity.
In this way, the unreacted hydrazine in the solid can be suitably washed out by placing the solid (nickel-hydrazine complex) and passing water.
前記洗浄により、固形物（ニッケル−ヒドラジン錯体）中に残留する未反応ヒドラジンを除去することができる。しかし、固形物中に残留する未反応ヒドラジンの量は、直接、分析することができない。本発明者らは、洗浄後の洗浄液の酸化還元電位をパラメーターとして、固形物中に残留する未反応ヒドラジンの量を推定することに想到した。具体的には、洗浄後の洗浄液の酸化還元電位が低い（マイナス数字が大きい）ほど、固形物中に残留する未反応のヒドラジン量が多いこととなる。 The unreacted hydrazine remaining in the solid (nickel-hydrazine complex) can be removed by the washing. However, the amount of unreacted hydrazine remaining in the solid cannot be analyzed directly. The present inventors have conceived that the amount of unreacted hydrazine remaining in the solid matter is estimated using the oxidation-reduction potential of the washing solution after washing as a parameter. Specifically, the lower the oxidation-reduction potential of the cleaning liquid after cleaning (the larger the negative number), the greater the amount of unreacted hydrazine remaining in the solid.
一方、固形物（ニッケル−ヒドラジン錯体）を洗浄する洗浄溶媒量は、固形分量に対して１０倍量以下、好ましくは６倍量以下を用いることが好ましい。これは、洗浄溶媒量が過大であると、製造されたニッケル−ヒドラジン錯体が分解してしまうおそれがあり、洗浄溶媒量が固形分量の１０倍量以下であれば、当該洗浄に伴うニッケル−ヒドラジン錯体の分解を最小限にすることができるからである。 On the other hand, the amount of the washing solvent for washing the solid (nickel-hydrazine complex) is 10 times or less, preferably 6 times or less the solid content. This is because if the amount of washing solvent is excessive, the produced nickel-hydrazine complex may be decomposed. If the amount of washing solvent is 10 times or less the solid content, nickel-hydrazine accompanying the washing This is because the decomposition of the complex can be minimized.
所定量の洗浄溶媒で固形物（ニッケル−ヒドラジン錯体）を洗浄した後、固形物に純水を通過させ、その通過水の酸化還元電位を測定する。このとき、通過水の酸化還元電位が−７００ｍＶ以上、好ましくは−６５０ｍＶ以上（尚、純水の酸化還元電位は＋２００ｍＶである。）であることが好ましい。通過水の酸化還元電位が−７００ｍＶ未満の場合は、固形物中に未反応のヒドラジンが残留していると考えられるからである。当該洗浄は、通過水の酸化還元電位が−７００ｍＶ以上、好ましくは−６５０ｍＶ以上となる迄、継続する。 After washing the solid (nickel-hydrazine complex) with a predetermined amount of washing solvent, pure water is passed through the solid, and the redox potential of the passing water is measured. At this time, the redox potential of the passing water is −700 mV or higher, preferably −650 mV or higher (note that the redox potential of pure water is +200 mV). This is because it is considered that unreacted hydrazine remains in the solid when the redox potential of the passing water is less than −700 mV. The washing is continued until the redox potential of the passing water becomes −700 mV or more, preferably −650 mV or more.
（ニッケル−ヒドラジン錯体の乾燥工程）
洗浄を終了した固形物（ニッケル−ヒドラジン錯体）を乾燥させる。
具体的には、上記洗浄を終了した固形物（ニッケル−ヒドラジン錯体）を回収し、乾燥装置にて乾燥させる。乾燥装置はＮ２ガスを流した乾燥機やオーブン、真空乾燥機などが使用できるが、真空乾燥機の方が固形物内部の水分も除去することができるため好ましい。乾燥させる際には固形物をできるだけ細かく粉砕し、その厚みが、できるだけ薄くなるように広げておくことが好ましい。こうすることで水分が蒸発しやすくなる。固形物の乾燥条件は、乾燥温度は２０〜５０℃、好ましくは３０〜５０℃、減圧度は大気圧を基準として、−０．０５ＭＰａ以下が好ましい。減圧時にはＮ２ガスを流して乾燥を促進させることも可能である。乾燥させた固形物中の水分量が２質量％以下となる迄、実施することが望ましい。固形物中の水分量が２質量％以下であれば、ニッケル−ヒドラジン錯体の分解を抑制することが可能だからである。
(Drying process of nickel-hydrazine complex)
The solid matter (nickel-hydrazine complex) that has been washed is dried.
Specifically, the solid (nickel-hydrazine complex) that has been washed is collected and dried with a drying apparatus. As the drying device, a dryer, an oven, a vacuum dryer, or the like in which N 2 gas is flowed can be used. However, the vacuum dryer is preferable because it can remove moisture inside the solid matter. When drying, it is preferable to pulverize the solid as finely as possible and spread it so that its thickness is as thin as possible. By doing so, moisture easily evaporates. As for the drying conditions of the solid, the drying temperature is 20 to 50 ° C., preferably 30 to 50 ° C., and the degree of vacuum is preferably −0.05 MPa or less based on the atmospheric pressure. It is also possible to promote drying by flowing N 2 gas during decompression. It is desirable to carry out until the water content in the dried solid becomes 2% by mass or less. This is because the decomposition of the nickel-hydrazine complex can be suppressed if the water content in the solid is 2% by mass or less.
（ニッケル−ヒドラジン錯体の再分散工程）
上記より得られた乾燥させたニッケル−ヒドラジン錯体と、凝集防止剤と、アルカリとを、溶媒へ添加して分散液を得る。
具体的には、乾燥させたニッケル−ヒドラジン錯体を、凝集防止剤を分散または溶解させた溶媒（純水が好ましい。）中に添加し、超音波処理やミキサーなどによって攪拌し、ニッケル−ヒドラジン錯体を溶媒中に分散させ、分散液を得ることが好ましい。尚、本発明において、溶媒に凝集防止剤を添加して「分散または溶解させた旨」を記載したのは、当該溶媒への凝集防止剤の添加量と溶解度との関係から、凝集防止剤が当該溶媒に溶解する場合と、溶解しきれずに分散する場合とがあることを説明したものである。
尤も、乾燥させたニッケル−ヒドラジン錯体の分散は、次のニッケルナノ粒子製造工程でアルカリの添加と同時に行っても良いが、より分散性の高いニッケルナノ粒子を得るためには、予め溶媒等の液に分散させる方が良い。また凝集防止剤の添加は、ニッケル−ヒドラジン錯体を溶媒中に分散させた後でも良い。溶媒の温度は、ニッケル−ヒドラジン錯体の分解を回避する観点から３０℃以下が好ましい。
(Redispersion step of nickel-hydrazine complex)
The dried nickel-hydrazine complex obtained above, an aggregation inhibitor, and an alkali are added to a solvent to obtain a dispersion.
Specifically, the dried nickel-hydrazine complex is added to a solvent (pure water is preferred) in which the aggregation inhibitor is dispersed or dissolved, and stirred by ultrasonic treatment or a mixer, and then the nickel-hydrazine complex. Is preferably dispersed in a solvent to obtain a dispersion. In the present invention, the fact that the aggregation inhibitor is added to the solvent and “dispersed or dissolved” is described because the aggregation inhibitor is based on the relationship between the amount of the aggregation inhibitor added to the solvent and the solubility. It explains that there are a case where it is dissolved in the solvent and a case where it is dispersed without being completely dissolved.
However, the dispersion of the dried nickel-hydrazine complex may be performed simultaneously with the addition of alkali in the next nickel nanoparticle production process, but in order to obtain nickel nanoparticles with higher dispersibility, a solvent or the like is previously used. It is better to disperse in the liquid. The aggregation inhibitor may be added after the nickel-hydrazine complex is dispersed in a solvent. The temperature of the solvent is preferably 30 ° C. or less from the viewpoint of avoiding the decomposition of the nickel-hydrazine complex.
（凝集防止剤）
本発明に係る凝集防止剤はニッケル−ヒドラジン錯体の再分散工程において溶媒中に分散させておき、本発明に係るニッケルナノ粒子をペーストやインクの原料として使用する際、当該ニッケルナノ粒子の凝集を抑制し分散性を維持させる為のものである。つまり、本発明に係る凝集防止剤は、ニッケル−ヒドラジン錯体から生成するニッケルナノ粒子の表面に付着して被覆することで、ニッケルナノ粒子同士の凝集を抑制するものである。そして、上記ニッケル−ヒドラジン錯体の再分散工程において溶媒（純水が好ましい。）中に分散させる観点から、当該凝集防止剤は水溶性であることが好ましい。
当該凝集防止剤の添加量が、前記ニッケル化合物溶液中に含有されるニッケル量の３.０モル％以下（但し、凝集防止剤のモル数は、当該凝集防止剤の平均分子量をもって算出した。）であれば、後述するニッケルナノ粒子の製造工程においてニッケルの還元が進み、ニッケルナノ粒子を得ることが出来る。さらに、当該凝集防止剤の添加量が、前記ニッケル化合物溶液中に含有されるニッケル量の０．０２モル％以上（同上）、０．３モル％以下（同上）、さらに好ましくは０．０２６％以上（同上）、０．２６モル％以下（同上）であれば分散性の良好なニッケルナノ粒子を得ることが出来た。
(Aggregation inhibitor)
The aggregation inhibitor according to the present invention is dispersed in a solvent in the step of redispersing the nickel-hydrazine complex. When the nickel nanoparticles according to the present invention are used as a raw material for paste or ink, the aggregation of the nickel nanoparticles is prevented. It is for suppressing and maintaining dispersibility. That is, the aggregation inhibitor according to the present invention suppresses aggregation of nickel nanoparticles by adhering to and covering the surface of nickel nanoparticles generated from a nickel-hydrazine complex. From the viewpoint of dispersing in a solvent (pure water is preferred) in the nickel-hydrazine complex redispersion step, the aggregation inhibitor is preferably water-soluble.
The addition amount of the aggregation inhibitor is 3.0 mol% or less of the amount of nickel contained in the nickel compound solution (however, the number of moles of the aggregation inhibitor was calculated by the average molecular weight of the aggregation inhibitor). If so, reduction of nickel proceeds in the nickel nanoparticle production process described later, and nickel nanoparticles can be obtained. Furthermore, the addition amount of the anti-aggregation agent is 0.02 mol% or more (same as above), 0.3 mol% or less (same as above), more preferably 0.026% of the amount of nickel contained in the nickel compound solution. Above (same as above) and 0.26 mol% or less (same as above), nickel nanoparticles having good dispersibility could be obtained.
当該凝集防止剤の具体例としては、ポリエチレンイミン、ポリビニルアミン、ポリアリルアミンなどの高分子アミン、およびそれらの一部を変性させた化合物等を挙げることが出来るが、ポリエチレンイミンが最も好ましい。当該ポリエチレンイミンの構造としては枝分かれ、直鎖状のどちらでも良い。当該ポリエチレンイミンの平均分子量は、特に制限はないが、溶媒の増粘制御や粒子への被覆量制御の観点から、平均分子量２０,０００以下が好ましく、より好ましくは２，０００以下である。 Specific examples of the anti-aggregation agent include high molecular amines such as polyethyleneimine, polyvinylamine, and polyallylamine, and compounds obtained by modifying a part thereof, but polyethyleneimine is most preferable. The polyethyleneimine structure may be branched or linear. The average molecular weight of the polyethyleneimine is not particularly limited, but is preferably 20,000 or less, more preferably 2,000 or less, from the viewpoint of controlling the thickening of the solvent or controlling the coating amount on the particles.
凝集防止剤として水溶性であるポリエチレンイミン等を用いる場合、当該凝集防止剤を純水中に添加し、超音波処理やマグネットスティーラー、ミキサーなどによって攪拌し溶解させてから、上記ニッケル−ヒドラジン錯体の再分散工程における溶媒中に添加するのが好ましいが、上記ニッケル−ヒドラジン錯体を溶媒中に再分散させた後、当該凝集防止剤を添加して分散または溶解させても良い。当該凝集防止剤を先に溶媒へ分散または溶解させる時には、当該凝集防止剤の分散または溶解を早めるために１００℃以下に加温して溶解させても良い。 When water-soluble polyethyleneimine or the like is used as an aggregation inhibitor, the aggregation inhibitor is added to pure water and stirred and dissolved by ultrasonic treatment, a magnetic stealer, a mixer, or the like, and then the nickel-hydrazine complex is mixed. Although it is preferable to add to the solvent in the redispersion step, after the nickel-hydrazine complex is redispersed in the solvent, the aggregation inhibitor may be added and dispersed or dissolved. When the aggregation preventing agent is first dispersed or dissolved in a solvent, the aggregation preventing agent may be dissolved by heating to 100 ° C. or less in order to accelerate the dispersion or dissolution of the aggregation preventing agent.
（ニッケルナノ粒子の製造工程）
水中に分散したニッケル−ヒドラジン錯体から、ニッケルナノ粒子を製造する工程である。
得られた分散液を攪拌しながら２０〜６０℃、好ましくは３０〜５０℃まで昇温してからアルカリを添加する。分散液が６０℃以下なら、ニッケル−ヒドラジン錯体が安定だからである。このとき撹拌羽根等を用いて十分に撹拌することが好ましい（例えば７００ｒｐｍ）。
(Manufacturing process of nickel nanoparticles)
This is a process for producing nickel nanoparticles from a nickel-hydrazine complex dispersed in water.
While stirring the obtained dispersion, the temperature is raised to 20 to 60 ° C., preferably 30 to 50 ° C., and then an alkali is added. This is because the nickel-hydrazine complex is stable when the dispersion is 60 ° C. or lower. At this time, it is preferable to sufficiently stir using a stirring blade or the like (for example, 700 rpm).
分散液の昇温時間は、例えば４０℃〜６０℃まで昇温するなら、６０分間以内が良く、好ましくは３０分間以内であり、１５分間以内がさらに好ましい。分散液における４０℃〜６０℃までの昇温時間が６０分間以内なら、ニッケル−ヒドラジン錯体が安定だからである。
前記アルカリとしては、水酸化ナトリウム水溶液、水酸化カリウム水溶液等が使用できる。これらアルカリ水溶液の濃度は、５０質量％以下であると水溶液の粘度が上昇せず、作業性に優れる。
加温された分散液へのアルカリの添加量は、分散液に含まれるニッケル−ヒドラジン錯体中のニッケル１モルに対して、３〜１２モル、好ましくは６〜１２モル、最も好ましくは１２モルである。
分散液への、アルカリの添加方法は、一挙に添加することが好ましく、添加時間１０秒以内で加圧添加することも好ましい。添加速度が速いと、ニッケル−ヒドラジン錯体の還元が一斉に開始され、生成するニッケルナノ粒子の粒径分布が狭くなり好ましい。
アルカリの添加時の雰囲気は、大気下、Ｎ２雰囲気下、Ａｒなどの不活性ガス雰囲気下とするのが好ましい、中でもＮ２雰囲気下が好ましい。
当該アルカリの添加後、分散液を１時間〜４時間、好ましくは１時間〜２時間、熟成させてニッケルナノ粒子を生成させる。
The temperature rise time of the dispersion is, for example, within 60 minutes, preferably within 30 minutes, more preferably within 15 minutes if the temperature is raised to 40 ° C to 60 ° C. This is because the nickel-hydrazine complex is stable when the temperature rise time from 40 ° C. to 60 ° C. in the dispersion is within 60 minutes.
As the alkali, an aqueous sodium hydroxide solution, an aqueous potassium hydroxide solution or the like can be used. When the concentration of these alkaline aqueous solutions is 50% by mass or less, the viscosity of the aqueous solution does not increase and the workability is excellent.
The amount of alkali added to the heated dispersion is 3 to 12 moles, preferably 6 to 12 moles, and most preferably 12 moles relative to 1 mole of nickel in the nickel-hydrazine complex contained in the dispersion. is there.
As a method of adding alkali to the dispersion, it is preferable to add at once, and it is also preferable to add under pressure within 10 seconds. When the addition rate is high, the reduction of the nickel-hydrazine complex is started all at once, and the particle size distribution of the produced nickel nanoparticles becomes narrow, which is preferable.
The atmosphere at the time of addition of alkali is preferably air, N 2 atmosphere, or an inert gas atmosphere such as Ar, and N 2 atmosphere is particularly preferable.
After the addition of the alkali, the dispersion is aged for 1 hour to 4 hours, preferably 1 hour to 2 hours to produce nickel nanoparticles.
生成したニッケルナノ粒子を固液分離によって分散液から回収し、洗浄した後、乾燥を行ってニッケルナノ粒子を得た。
固液分離および洗浄方法としては、加圧ろ過、吸引ろ過、フィルタープレス等が使用できる（但し、孔径が０．５μｍ以下であることが好ましい。）。洗浄水は、製造したニッケルナノ粒子の重量の１０倍以下が好ましく、さらには５〜７倍が好ましい。
乾燥は低温乾燥が好ましいので、真空乾燥機、Ｎ２、Ａｒなどの不活性ガス流通下での乾燥が好ましい。具体的には、２０℃〜５０℃、好ましくは３０℃〜５０℃の温度下とし、Ｎ２雰囲気下か、真空乾燥にて１２時間以上乾燥させることが好ましい。
また、当該真空乾燥の前に、固液分離されたニッケルナノ粒子をエタノール、２−プロパノール等を用いてアルコール洗浄し、水分を除去しておくことも好ましい構成である。
The produced nickel nanoparticles were recovered from the dispersion by solid-liquid separation, washed, and then dried to obtain nickel nanoparticles.
As the solid-liquid separation and washing method, pressure filtration, suction filtration, filter press and the like can be used (however, the pore diameter is preferably 0.5 μm or less). The washing water is preferably 10 times or less, more preferably 5 to 7 times the weight of the produced nickel nanoparticles.
Since drying is preferably performed at a low temperature, drying under a circulation of an inert gas such as a vacuum dryer, N 2 , or Ar is preferable. Specifically, it is preferable that the temperature is 20 ° C. to 50 ° C., preferably 30 ° C. to 50 ° C., and is dried in an N 2 atmosphere or vacuum drying for 12 hours or more.
Moreover, it is also a preferable structure that the solid-liquid separated nickel nanoparticles are washed with alcohol using ethanol, 2-propanol or the like to remove moisture before the vacuum drying.
以上、説明した液相反応を用いた製造方法により、平均粒径１００ｎｍ以下であっても有機溶媒中での分散に優れたニッケルナノ粒子、並びに、当該ニッケルナノ粒子を含むニッケルナノ粒子粉を、低コストで高い生産性をもって製造することが出来た。 As described above, according to the production method using the liquid phase reaction, nickel nanoparticles excellent in dispersion in an organic solvent even when the average particle size is 100 nm or less, and nickel nanoparticle powder containing the nickel nanoparticles, We were able to manufacture with low cost and high productivity.
（本発明に係るニッケルナノ粒子）
本発明に係るニッケルナノ粒子は、表面が凝集防止剤によって被覆され、走査型電子顕微鏡画像から算出した一次粒子径が１００ｎｍ以下であり、動的光散乱粒度分布測定により測定される二次粒子径が２００ｎｍ以下に分散しているニッケルナノ粒子である。
当該構成を有する本発明に係るニッケルナノ粒子は、平均粒径１００ｎｍ以下であっても有機溶媒中での分散に優れていた。この結果、例えば、ニッケルナノ粒子に、所定量のテルピネオールおよび所定量のエチルセルロースを加えて３本ロールで混練するといった公知の方法で、容易に、一次粒子径が１００ｎｍ以下であり、かつ二次凝集の少ない分散性の良好な高特性のニッケルペーストを製造することが出来た。
製造されたニッケルペーストは、小型化、高性能化されたエレクトロニクス用途のニッケルペーストとして好適なものであった。
(Nickel nanoparticles according to the present invention)
The nickel nanoparticles according to the present invention have a surface coated with an anti-aggregation agent, a primary particle size calculated from a scanning electron microscope image is 100 nm or less, and a secondary particle size measured by dynamic light scattering particle size distribution measurement. Are nickel nanoparticles dispersed in 200 nm or less.
The nickel nanoparticles according to the present invention having such a configuration were excellent in dispersion in an organic solvent even when the average particle size was 100 nm or less. As a result, for example, a primary particle diameter of 100 nm or less and secondary aggregation can be easily performed by a known method in which a predetermined amount of terpineol and a predetermined amount of ethyl cellulose are added to nickel nanoparticles and kneaded with three rolls. A high-quality nickel paste with low dispersibility and good characteristics could be produced.
The manufactured nickel paste was suitable as a nickel paste for electronics applications with reduced size and higher performance.
［実施例１］
（ニッケル−ヒドラジン錯体の製造）
塩化ニッケル・六水和物（和光純薬工業製）１５．２１ｇを純水２７．６７ｇに溶解させ、１５分間かけて温度６０℃に調温し、Ｎ２雰囲気下で回転羽根により７００ｒｐｍで撹拌しながら、２０℃に調温した８０質量％ヒドラジン一水和物（昭和化学製）９．９８ｇを、１ｇ／ｍｉｎの速度で連続的に添加し、ニッケル−ヒドラジン錯体を生成した。
[Example 1]
(Production of nickel-hydrazine complex)
15.21 g of nickel chloride hexahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) is dissolved in 27.67 g of pure water, adjusted to a temperature of 60 ° C. over 15 minutes, and stirred at 700 rpm with a rotating blade in an N 2 atmosphere. However, 9.98 g of 80% by mass hydrazine monohydrate (manufactured by Showa Chemical Co., Ltd.) adjusted to 20 ° C. was continuously added at a rate of 1 g / min to produce a nickel-hydrazine complex.
（ニッケル−ヒドラジン錯体の回収、洗浄・乾燥）
ニッケル−ヒドラジン錯体が生成した液を、加圧ろ過器（ＫＳＴ−１４２、東洋濾紙会社製）を使用し、固形物（ニッケル−ヒドラジン錯体）を回収した。濾紙は孔径１．０μｍのＰＴＦＥ濾紙（Ｈ１００Ａ１４２Ｃ、東洋濾紙会社製）を用いた。
回収された固形物（ニッケル−ヒドラジン錯体）は、ＰＴＦＥ濾紙上に、厚みが最も薄い箇所で２ｍｍ以上、最も厚い箇所で５ｍｍ以下であった。次に純水５００ｍｌを投入することで、未反応のヒドラジンなどの不純物を洗い流した。この時、通水後の洗浄液の酸化還元電位は−４４８ｍＶであった。
洗浄した固形物（ニッケル−ヒドラジン錯体）を減圧乾燥機内に装填し、減圧度を−０．０５ＭＰａ以下にしてＮ２ガスを流しながら、室温で１２時間以上減圧乾燥を行った。
(Recovery, washing and drying of nickel-hydrazine complex)
The liquid in which the nickel-hydrazine complex was produced was collected using a pressure filter (KST-142, manufactured by Toyo Roshi Kaisha Co., Ltd.) to recover a solid (nickel-hydrazine complex). As the filter paper, PTFE filter paper (H100A142C, manufactured by Toyo Filter Paper Co., Ltd.) having a pore size of 1.0 μm was used.
The collected solid (nickel-hydrazine complex) was 2 mm or more at the thinnest part and 5 mm or less at the thickest part on the PTFE filter paper. Next, 500 ml of pure water was added to wash away impurities such as unreacted hydrazine. At this time, the oxidation-reduction potential of the cleaning liquid after passing water was −448 mV.
The washed solid material (nickel-hydrazine complex) was loaded into a vacuum dryer, and the vacuum was dried at room temperature for 12 hours or more while flowing N 2 gas at a reduced pressure of −0.05 MPa or less.
（凝集防止剤の分散）
純水１７ｇ中にポリエチレンイミン（和光純薬工業製、平均分子量６００）を０．１ｇ（平均分子量換算でニッケル量に対し０．２６モル％）添加し、超音波分散によって溶解させた。
(Dispersion of anti-agglomeration agent)
0.1 g of polyethyleneimine (manufactured by Wako Pure Chemical Industries, average molecular weight 600) was added to 17 g of pure water (0.26 mol% relative to the amount of nickel in terms of average molecular weight) and dissolved by ultrasonic dispersion.
（錯体の分散、ニッケルナノ粒子の製造）
乾燥した固形物（ニッケル−ヒドラジン錯体）１２ｇを上記ポリエチレンイミンを溶解させた溶液と混合し、超音波処理をしながら１０分間程度攪拌を行い、分散液を得た。
Ｎ２雰囲気下にて、当該分散液を攪拌しながら１５分間で５０℃まで昇温し、２０℃に調温した濃度５０質量％の水酸化ナトリウム水溶液（和光純薬工業製）６３．２１ｇを一挙に添加した。当該水酸化ナトリウム溶液添加後、当該分散液を２時間熟成し、ニッケルナノ粒子を製造した。
(Dispersion of complex, production of nickel nanoparticles)
12 g of the dried solid (nickel-hydrazine complex) was mixed with the solution in which the polyethyleneimine was dissolved, and stirred for about 10 minutes while performing ultrasonic treatment to obtain a dispersion.
In a N 2 atmosphere, while stirring the dispersion, the temperature was raised to 50 ° C. over 15 minutes, and 63.21 g of a 50% by weight aqueous sodium hydroxide solution (manufactured by Wako Pure Chemical Industries) adjusted to 20 ° C. was added. Added all at once. After the addition of the sodium hydroxide solution, the dispersion was aged for 2 hours to produce nickel nanoparticles.
（ニッケルナノ粒子の回収）
生成した固形物（ニッケルナノ粒子）を加圧ろ過器によって回収し、純水２Ｌで洗浄した。濾紙は孔径０．２μｍのＰＴＦＥ濾紙（Ｈ０２０Ａ１４２Ｃ、東洋濾紙会社製）を用いた。そして、生成した固形物を２−プロパノール３００ｍｌでアルコール洗浄した。その後、固形物（ニッケルナノ粒子）を減圧乾燥機内に装填し、−０．０５ＭＰａ以下に減圧しＮ２ガスを流しながら、室温で１２時間減圧乾燥を行って実施例１に係るニッケルナノ粒子を得た。
(Recovery of nickel nanoparticles)
The produced solid matter (nickel nanoparticles) was collected by a pressure filter and washed with 2 L of pure water. The filter paper used was PTFE filter paper (H020A142C, manufactured by Toyo Filter Paper Co., Ltd.) having a pore size of 0.2 μm. The produced solid was washed with alcohol with 300 ml of 2-propanol. Thereafter, the solid matter (nickel nanoparticles) was loaded into a vacuum dryer, and the nickel nanoparticles according to Example 1 were dried at room temperature for 12 hours while reducing the pressure to −0.05 MPa or less and flowing N 2 gas. Obtained.
（ニッケルナノ粒子の性状、特性）
〈一次粒子径測定〉
実施例１に係るニッケルナノ粒子の一次粒子径を、走査型電子顕微鏡Ｓ−４７００（日立製作所製）を用いて測定した。具体的には、当該走査型電子顕微鏡により得られた１１万倍率（一部５０万倍率）の画像を用い、粒子径測定用ソフトウェアＭｏｔｉｃ Ｉｍａｇｅｓ Ｐｌｕｓ（ホーザン製）により、ニッケルナノ粒子の一次粒子径を算出した。
算出する粒子数は信頼性の観点より、２００個以上の粒子から算出した。算出した粒子径の値を計算ソフトにてヒストグラム解析をすることで、一次粒子径を算出した。ここで言う一次粒子径はヒストグラム解析をした頻度分布における５０％粒子径である。
実施例１で得られたニッケルナノ粒子は、略球状の形をしていた。そして、ニッケルナノ粒子の一次粒子径は８８ｎｍであった。
実施例１に係るニッケルナノ粒子の５万倍率のＳＥＭ写真を、図１に示す。
(Characteristics and properties of nickel nanoparticles)
<Measurement of primary particle size>
The primary particle diameter of the nickel nanoparticles according to Example 1 was measured using a scanning electron microscope S-4700 (manufactured by Hitachi, Ltd.). Specifically, the primary particle diameter of the nickel nanoparticles is obtained by using the image of 110,000 magnification (partially 500,000 magnification) obtained by the scanning electron microscope and using the particle diameter measurement software Motic Images Plus (manufactured by Hozan). Was calculated.
The number of particles to be calculated was calculated from 200 or more particles from the viewpoint of reliability. The primary particle size was calculated by performing histogram analysis on the calculated particle size value using calculation software. The primary particle diameter here is a 50% particle diameter in a frequency distribution obtained by histogram analysis.
The nickel nanoparticles obtained in Example 1 had a substantially spherical shape. And the primary particle diameter of the nickel nanoparticle was 88 nm.
An SEM photograph at a magnification of 50,000 of the nickel nanoparticles according to Example 1 is shown in FIG.
〈二次粒子径測定〉
実施例１に係るニッケルナノ粒子の二次粒子径を、動的光散乱粒度分布測定装置を用いて測定した。具体的には、製造したニッケルナノ粒子０．５ｇを、溶媒である２−プロパノール１００ｍｌ中に添加した。次に、その溶媒へ、超音波生成機ｕｓ−６００ＴＣＶＰ（ニッセイ製）にて３０秒間超音波を照射し、ニッケルナノ粒子を溶媒中へ分散させた。ニッケルナノ粒子分散後の溶媒に対し、液温２５℃の条件にて動的光散乱粒度分布測定装置ＦＰＡＲ−１０００（大塚電子製）を用いて二次粒子径を測定した。ここで言う二次粒子径とは、測定された二次粒子の粒度分布の５０％粒子径である。
実施例１で得られたニッケルナノ粒子の二次粒子径は１６０ｎｍであった。
<Secondary particle size measurement>
The secondary particle diameter of the nickel nanoparticles according to Example 1 was measured using a dynamic light scattering particle size distribution measuring apparatus. Specifically, 0.5 g of the produced nickel nanoparticles were added to 100 ml of 2-propanol as a solvent. Next, the solvent was irradiated with ultrasonic waves for 30 seconds with an ultrasonic generator us-600TCVP (manufactured by Nissei) to disperse the nickel nanoparticles in the solvent. The secondary particle diameter was measured using a dynamic light scattering particle size distribution analyzer FPAR-1000 (manufactured by Otsuka Electronics Co., Ltd.) under the condition of a liquid temperature of 25 ° C. with respect to the solvent after the nickel nanoparticles were dispersed. The secondary particle size referred to here is the 50% particle size of the measured particle size distribution of the secondary particles.
The secondary particle diameter of the nickel nanoparticles obtained in Example 1 was 160 nm.
〈沈降度評価〉
実施例１に係るニッケルナノ粒子の再凝集のし難さを沈降度にて評価した。具体的には、実施例１に係るニッケルナノ粒子０．５ｇを、溶媒である２−プロパノール１００ｍｌ中に添加した。次に、その溶媒へ、超音波生成機ｕｓ−６００ＴＣＶＰ（ニッセイ製）にて３０秒間超音波を照射し、溶媒中にニッケルナノ粒子を分散させた。ニッケルナノ粒子分散後の分散液を、ガラス製試験管Ａ・１５（マルエム製）に移した後、当該試験管の口に栓をし、試験管立てにて２４時間室温で静置した。そして、静置後のニッケルナノ粒子の沈殿具合を目視で確認して、評価を行った。
評価方法としては、分散液全体が黒色をしており、沈降している粒子がなければ○、上澄みが、静置初期よりも薄くなっており、沈降物が確認される場合には△、上澄みが透明で、粒子が再凝集により完全に沈降している場合には×と評価した。
実施例１に係るニッケルナノ粒子は、２４時間静置後も沈降せずに良好な分散性を示していた。
以上の結果を表１に示す。
<Evaluation of sedimentation>
The difficulty of re-aggregation of the nickel nanoparticles according to Example 1 was evaluated based on the degree of sedimentation. Specifically, 0.5 g of nickel nanoparticles according to Example 1 was added to 100 ml of 2-propanol as a solvent. Next, ultrasonic waves were applied to the solvent with an ultrasonic generator us-600TCVP (manufactured by Nissei) for 30 seconds to disperse the nickel nanoparticles in the solvent. After the dispersion of the nickel nanoparticles dispersed was transferred to a glass test tube A / 15 (manufactured by Maruemu), the mouth of the test tube was capped and allowed to stand at room temperature for 24 hours in a test tube stand. And it evaluated by checking visually the precipitation condition of the nickel nanoparticle after stationary.
As an evaluation method, the whole dispersion is black, and there is no sedimented particle, ○, the supernatant is thinner than the initial stage of standing, and when the sediment is confirmed, Δ, the supernatant Was transparent and the particles were completely settled by reaggregation, and were evaluated as x.
The nickel nanoparticles according to Example 1 showed good dispersibility without settling after standing for 24 hours.
The results are shown in Table 1.
［実施例２］
実施例１の製造方法において、ポリエチレンイミンの添加量を０．０１ｇ（平均分子量換算でニッケルに対し０．０２６モル％）に変化させた以外は同様の製法にてニッケルナノ粒子の製造を行った。
得られたニッケルナノ粒子は略球状の形をしており、一次粒子径が８０ｎｍ、二次粒子径は１８１ｎｍであった。またニッケルナノ粒子の分散液は２４時間静置後も良好な分散性を示していた。
得られた実施例２に係るニッケルナノ粒子の特性を、実施例１と同様に表１に示す。
実施例２に係るニッケルナノ粒子の５万倍率のＳＥＭ写真を、図２に示す。
実施例２に係るニッケルナノ粒子は、２４時間静置後も沈降せずに良好な分散性を示していた。
[Example 2]
In the production method of Example 1, nickel nanoparticles were produced by the same production method except that the addition amount of polyethyleneimine was changed to 0.01 g (0.026 mol% with respect to nickel in terms of average molecular weight). .
The obtained nickel nanoparticles had a substantially spherical shape, and the primary particle diameter was 80 nm and the secondary particle diameter was 181 nm. The nickel nanoparticle dispersion showed good dispersibility even after standing for 24 hours.
The characteristics of the obtained nickel nanoparticles according to Example 2 are shown in Table 1 as in Example 1.
A SEM photograph of the nickel nanoparticles according to Example 2 at a magnification of 50,000 is shown in FIG.
The nickel nanoparticles according to Example 2 showed good dispersibility without settling after standing for 24 hours.
［比較例１］
実施例１の製造方法において、ニッケル−ヒドラジン錯体を生成した後、錯体の洗浄を行わずにニッケルナノ粒子の合成を行った。
まず実施例１と同様にしてニッケル−ヒドラジン錯体の生成を行った。この時の懸濁液の酸化還元電位は−７５５ｍＶであった。次に錯体の懸濁液を５０℃まで冷却した後、ポリエチレンイミン（和光純薬工業製、平均分子量６００）０．１ｇ（平均分子量換算でニッケルに対し０．２６モル％）を純水１ｇに溶解させた水溶液を添加した。ポリエチレンイミン水溶液を添加して１０分間攪拌した後、水酸化ナトリウム溶液を添加して反応を行った。
その結果、４時間熟成後においても錯体のほとんどはニッケル単体に還元されず、ニッケルナノ粒子を生成することはできなかった。このことより、錯体の洗浄工程がなければニッケルナノ粒子の製造が困難であることが分かった。
比較例１に係るニッケルナノ粒子は得られなかったので、表１にはデータを記載していない。
比較例１に係るニッケル粒子の５万倍率のＳＥＭ写真を、図３に示す。
[Comparative Example 1]
In the production method of Example 1, after producing a nickel-hydrazine complex, nickel nanoparticles were synthesized without washing the complex.
First, a nickel-hydrazine complex was produced in the same manner as in Example 1. At this time, the oxidation-reduction potential of the suspension was -755 mV. Next, after cooling the suspension of the complex to 50 ° C., 0.1 g of polyethyleneimine (manufactured by Wako Pure Chemical Industries, average molecular weight 600) (0.26 mol% relative to nickel in terms of average molecular weight) was added to 1 g of pure water. A dissolved aqueous solution was added. After adding a polyethyleneimine aqueous solution and stirring for 10 minutes, a sodium hydroxide solution was added for reaction.
As a result, even after aging for 4 hours, most of the complex was not reduced to nickel alone, and nickel nanoparticles could not be produced. From this, it was found that it is difficult to produce nickel nanoparticles without a complex washing step.
Since the nickel nanoparticles according to Comparative Example 1 were not obtained, no data is shown in Table 1.
A SEM photograph of nickel particles according to Comparative Example 1 at a magnification of 50,000 is shown in FIG.
［比較例２、３］
比較例１の製造方法においてニッケル−ヒドラジン錯体がニッケル単体に還元されなかったことから、ポリエチレンイミンの添加量を、比較例２では０．０１ｇ（平均分子量換算でニッケルに対し０．０２６モル％）に減量して添加、比較例３では添加なし、として反応を行った。その結果、２時間熟成後にニッケル粒子を得た。
しかしながら、得られたニッケル粒子は、一次粒子径が比較例２では２３３ｎｍ、比較例３では２２８ｎｍであり、ニッケルナノ粒子を得ることは出来なかった。一方、二次粒子径は、比較例２では２７４ｎｍ、比較例３では２２８ｎｍであった。比較例１および比較例２、３の結果より、ニッケルーヒドラジンの錯体洗浄工程がなければ、ニッケルナノ粒子を得ることが困難であることが確認された。
得られた比較例２、３に係るニッケル粒子の特性を、実施例１と同様に表１に示す。
比較例２、３に係るニッケル粒子の５万倍率のＳＥＭ写真を、図４、５に示す。
比較例２、３に係るニッケル粒子は、２４時間静置後、粒子が再凝集により完全に沈降していた。
[Comparative Examples 2 and 3]
Since the nickel-hydrazine complex was not reduced to simple nickel in the production method of Comparative Example 1, the amount of polyethyleneimine added was 0.01 g in Comparative Example 2 (0.026 mol% based on nickel in terms of average molecular weight). The reaction was carried out with the addition being reduced to No, and no addition in Comparative Example 3. As a result, nickel particles were obtained after aging for 2 hours.
However, the obtained nickel particles had a primary particle size of 233 nm in Comparative Example 2 and 228 nm in Comparative Example 3, and nickel nanoparticles could not be obtained. On the other hand, the secondary particle diameter was 274 nm in Comparative Example 2 and 228 nm in Comparative Example 3. From the results of Comparative Example 1 and Comparative Examples 2 and 3, it was confirmed that it was difficult to obtain nickel nanoparticles without the nickel-hydrazine complex washing step.
The characteristics of the obtained nickel particles according to Comparative Examples 2 and 3 are shown in Table 1 as in Example 1.
4 and 5 show SEM photographs at 50,000 magnifications of the nickel particles according to Comparative Examples 2 and 3, respectively.
The nickel particles according to Comparative Examples 2 and 3 were completely settled by reaggregation after standing for 24 hours.
［比較例４］
実施例１の製造方法において、ポリエチレンイミンを添加しないこと以外は同様の製法にて合成を行い、ニッケルナノ粒子を得た。
得られた比較例４に係るニッケルナノ粒子の特性を表に示す。得られたニッケルナノ粒子は一次粒子径が７８ｎｍと、１００ｎｍ以下となったが、二次粒子径が２７５ｎｍであり二次凝集していることが分かった。また沈降度評価においても２４時間静置後に再凝集して沈殿することから、分散性が良好でないことが分かった。このことより、ポリエチレンイミンを添加しなければ、分散性の良好なニッケルナノ粒子を得ることが困難であることが分かった。
得られた比較例４に係るニッケルナノ粒子の特性を、実施例１と同様に表１に示す。
比較例４に係るニッケルナノ粒子の５万倍率のＳＥＭ写真を、図６に示す。
比較例４に係るニッケルナノ粒子は、２４時間静置後、粒子が再凝集により完全に沈降していた。
[Comparative Example 4]
In the production method of Example 1, synthesis was carried out by the same production method except that polyethyleneimine was not added to obtain nickel nanoparticles.
The characteristic of the nickel nanoparticle concerning the obtained comparative example 4 is shown to a table | surface. The obtained nickel nanoparticles had a primary particle diameter of 78 nm and 100 nm or less, but the secondary particle diameter was 275 nm, and it was found that secondary aggregation occurred. Also, in the sedimentation degree evaluation, it was found that the dispersibility was not good because it re-aggregated and settled after standing for 24 hours. From this, it was found that it is difficult to obtain nickel nanoparticles having good dispersibility unless polyethyleneimine is added.
The characteristics of the obtained nickel nanoparticles according to Comparative Example 4 are shown in Table 1 as in Example 1.
A SEM photograph of the nickel nanoparticles according to Comparative Example 4 at a magnification of 50,000 is shown in FIG.
The nickel nanoparticles according to Comparative Example 4 were completely settled by reaggregation after standing for 24 hours.
［比較例５］
実施例１の製造方法において、ポリエチレンイミンの添加量を３．０ｇ（平均分子量換算でニッケルに対し７．８モル％）として反応を行なった以外は、同様の製法にて合成を行った。
その結果、ニッケルの還元が進まず、ニッケルナノ粒子を得ることは出来なかった。
比較例５に係るニッケルナノ粒子は得られなかったので、表１にはデータを記載していない。
比較例５に係る粒子の５万倍率のＳＥＭ写真を、図７に示す。
[Comparative Example 5]
In the production method of Example 1, synthesis was carried out by the same production method, except that the reaction was carried out with the addition amount of polyethyleneimine being 3.0 g (7.8 mol% with respect to nickel in terms of average molecular weight).
As a result, nickel reduction did not proceed and nickel nanoparticles could not be obtained.
Since nickel nanoparticles according to Comparative Example 5 were not obtained, no data is shown in Table 1.
A SEM photograph of the particles according to Comparative Example 5 at a magnification of 50,000 is shown in FIG.
［まとめ］
上述した実施例、比較例より以下のことが判明した。
本発明に係るニッケル−ヒドラジン錯体からニッケル粒子を製造する製造方法において、ニッケル−ヒドラジン錯体の洗浄を本発明条件にすること、またアルカリ添加前に凝集防止剤を添加することで、一次粒子径が１００ｎｍ以下であり、二次粒子径が２００ｎｍ以下に分散しており、再凝集しにくい良好なニッケルナノ粒子を、容易に製造することができた。
これに対し、錯体の洗浄を行わないで凝集防止剤をアルカリ添加前に添加する製造方法や、凝集防止剤を添加しない製造方法、凝集防止剤の添加量が適切でない製造方法では、一次粒子径が１００ｎｍ以下で、かつ分散性の良好なニッケルナノ粒子を得ることは困難であった。
[Summary]
From the examples and comparative examples described above, the following was found.
In the production method for producing nickel particles from the nickel-hydrazine complex according to the present invention, the primary particle size is reduced by making the nickel-hydrazine complex washing the conditions of the present invention and adding an anti-aggregation agent before adding the alkali. Good nickel nanoparticles having a particle diameter of 100 nm or less and a secondary particle diameter dispersed in 200 nm or less and hardly re-aggregated could be easily produced.
On the other hand, in the production method in which the aggregation inhibitor is added before adding the alkali without washing the complex, the production method in which the aggregation inhibitor is not added, or the production method in which the addition amount of the aggregation inhibitor is not appropriate, the primary particle size It was difficult to obtain nickel nanoparticles having a dispersibility of 100 nm or less.
Claims (11)
前記生成したニッケル−ヒドラジン錯体溶液を固液分離し、ニッケル−ヒドラジン錯体を得る工程と、
前記得られたニッケル−ヒドラジン錯体を洗浄し、洗浄されたニッケル−ヒドラジン錯体を得る工程と、
前記洗浄されたニッケル−ヒドラジン錯体と、凝集防止剤と、アルカリとを、溶媒へ添加してニッケルナノ粒子を製造する工程とを有することを特徴とするニッケルナノ粒子の製造方法。 Producing a nickel-hydrazine complex solution from the nickel compound solution and the hydrazine compound solution;
Solid-liquid separation of the produced nickel-hydrazine complex solution to obtain a nickel-hydrazine complex;
Washing the obtained nickel-hydrazine complex to obtain a washed nickel-hydrazine complex;
A method for producing nickel nanoparticles, comprising the step of producing nickel nanoparticles by adding the washed nickel-hydrazine complex, an aggregation inhibitor, and an alkali to a solvent.
洗浄液として純水を用い、当該洗浄液を、ニッケル−ヒドラジン錯体を通過させることで洗浄を行い、当該洗浄後における洗浄液の酸化還元電位が−７００ｍＶ以上となるまで洗浄を継続することを特徴とする請求項１に記載のニッケルナノ粒子の製造方法。 In the step of washing the nickel-hydrazine complex,
Purified water is used as a cleaning liquid, and the cleaning liquid is cleaned by passing a nickel-hydrazine complex, and the cleaning is continued until the oxidation-reduction potential of the cleaning liquid after the cleaning becomes −700 mV or more. Item 2. A method for producing nickel nanoparticles according to Item 1.
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