JPH1088207A - Silver powder and its manufacture - Google Patents
Silver powder and its manufactureInfo
- Publication number
- JPH1088207A JPH1088207A JP8263601A JP26360196A JPH1088207A JP H1088207 A JPH1088207 A JP H1088207A JP 8263601 A JP8263601 A JP 8263601A JP 26360196 A JP26360196 A JP 26360196A JP H1088207 A JPH1088207 A JP H1088207A
- Authority
- JP
- Japan
- Prior art keywords
- silver powder
- silver
- paste
- coating
- density
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 title claims abstract description 127
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 23
- 239000011248 coating agent Substances 0.000 claims abstract description 47
- 238000000576 coating method Methods 0.000 claims abstract description 47
- NDVLTYZPCACLMA-UHFFFAOYSA-N silver oxide Chemical compound [O-2].[Ag+].[Ag+] NDVLTYZPCACLMA-UHFFFAOYSA-N 0.000 claims abstract description 32
- 229910052709 silver Inorganic materials 0.000 claims abstract description 31
- 239000004332 silver Substances 0.000 claims abstract description 31
- 239000007864 aqueous solution Substances 0.000 claims abstract description 29
- 238000006243 chemical reaction Methods 0.000 claims abstract description 29
- 239000002245 particle Substances 0.000 claims abstract description 23
- 239000002270 dispersing agent Substances 0.000 claims abstract description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 21
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 20
- 239000000758 substrate Substances 0.000 claims abstract description 17
- 229910001923 silver oxide Inorganic materials 0.000 claims abstract description 16
- 230000003746 surface roughness Effects 0.000 claims abstract description 13
- 238000007561 laser diffraction method Methods 0.000 claims abstract description 7
- 238000000034 method Methods 0.000 claims description 40
- 235000014113 dietary fatty acids Nutrition 0.000 claims description 13
- 239000000194 fatty acid Substances 0.000 claims description 13
- 229930195729 fatty acid Natural products 0.000 claims description 13
- 150000004665 fatty acids Chemical class 0.000 claims description 9
- GGCZERPQGJTIQP-UHFFFAOYSA-N sodium;9,10-dioxoanthracene-2-sulfonic acid Chemical compound [Na+].C1=CC=C2C(=O)C3=CC(S(=O)(=O)O)=CC=C3C(=O)C2=C1 GGCZERPQGJTIQP-UHFFFAOYSA-N 0.000 claims description 8
- 239000004094 surface-active agent Substances 0.000 claims description 7
- -1 fatty acid salt Chemical class 0.000 claims description 6
- 238000010304 firing Methods 0.000 claims description 6
- 239000000919 ceramic Substances 0.000 claims description 5
- 239000000084 colloidal system Substances 0.000 claims description 4
- 230000001681 protective effect Effects 0.000 claims description 4
- 238000010298 pulverizing process Methods 0.000 claims description 4
- 238000001914 filtration Methods 0.000 claims description 3
- 229910052751 metal Inorganic materials 0.000 claims description 3
- 239000002184 metal Substances 0.000 claims description 3
- 239000000243 solution Substances 0.000 abstract description 17
- 239000002002 slurry Substances 0.000 abstract description 10
- 230000009467 reduction Effects 0.000 abstract description 9
- 239000011521 glass Substances 0.000 abstract description 8
- 238000002156 mixing Methods 0.000 abstract description 5
- 230000002829 reductive effect Effects 0.000 abstract description 5
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 abstract description 4
- 150000003839 salts Chemical class 0.000 abstract description 3
- 238000005406 washing Methods 0.000 abstract description 2
- 239000012295 chemical reaction liquid Substances 0.000 abstract 1
- 230000001747 exhibiting effect Effects 0.000 abstract 1
- 238000000227 grinding Methods 0.000 abstract 1
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 12
- 238000006722 reduction reaction Methods 0.000 description 11
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 10
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 9
- 238000001035 drying Methods 0.000 description 7
- 239000000203 mixture Substances 0.000 description 7
- OAKJQQAXSVQMHS-UHFFFAOYSA-N Hydrazine Chemical compound NN OAKJQQAXSVQMHS-UHFFFAOYSA-N 0.000 description 6
- 239000004020 conductor Substances 0.000 description 6
- 239000000843 powder Substances 0.000 description 6
- 229910001961 silver nitrate Inorganic materials 0.000 description 6
- 239000010419 fine particle Substances 0.000 description 5
- 239000007788 liquid Substances 0.000 description 5
- 238000005259 measurement Methods 0.000 description 5
- 150000001412 amines Chemical class 0.000 description 4
- 238000007796 conventional method Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000001556 precipitation Methods 0.000 description 4
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- 238000004220 aggregation Methods 0.000 description 3
- 230000002776 aggregation Effects 0.000 description 3
- 239000003513 alkali Substances 0.000 description 3
- 239000003945 anionic surfactant Substances 0.000 description 3
- 239000007900 aqueous suspension Substances 0.000 description 3
- 239000008139 complexing agent Substances 0.000 description 3
- 239000002736 nonionic surfactant Substances 0.000 description 3
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 2
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 2
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 2
- FOIXSVOLVBLSDH-UHFFFAOYSA-N Silver ion Chemical compound [Ag+] FOIXSVOLVBLSDH-UHFFFAOYSA-N 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-N ammonia Natural products N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 239000002280 amphoteric surfactant Substances 0.000 description 2
- 239000012298 atmosphere Substances 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 239000003990 capacitor Substances 0.000 description 2
- 239000003093 cationic surfactant Substances 0.000 description 2
- 230000008602 contraction Effects 0.000 description 2
- 230000002209 hydrophobic effect Effects 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- HAAYBYDROVFKPU-UHFFFAOYSA-N silver;azane;nitrate Chemical compound N.N.[Ag+].[O-][N+]([O-])=O HAAYBYDROVFKPU-UHFFFAOYSA-N 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 description 1
- KWSLGOVYXMQPPX-UHFFFAOYSA-N 5-[3-(trifluoromethyl)phenyl]-2h-tetrazole Chemical compound FC(F)(F)C1=CC=CC(C2=NNN=N2)=C1 KWSLGOVYXMQPPX-UHFFFAOYSA-N 0.000 description 1
- 239000004925 Acrylic resin Substances 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 238000004438 BET method Methods 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 description 1
- 239000005751 Copper oxide Substances 0.000 description 1
- FEWJPZIEWOKRBE-JCYAYHJZSA-N Dextrotartaric acid Chemical compound OC(=O)[C@H](O)[C@@H](O)C(O)=O FEWJPZIEWOKRBE-JCYAYHJZSA-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
- WQZGKKKJIJFFOK-GASJEMHNSA-N Glucose Natural products OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-GASJEMHNSA-N 0.000 description 1
- 239000001358 L(+)-tartaric acid Substances 0.000 description 1
- 235000011002 L(+)-tartaric acid Nutrition 0.000 description 1
- FEWJPZIEWOKRBE-LWMBPPNESA-N L-(+)-Tartaric acid Natural products OC(=O)[C@@H](O)[C@H](O)C(O)=O FEWJPZIEWOKRBE-LWMBPPNESA-N 0.000 description 1
- 239000002211 L-ascorbic acid Substances 0.000 description 1
- 235000000069 L-ascorbic acid Nutrition 0.000 description 1
- 239000004280 Sodium formate Substances 0.000 description 1
- 235000021355 Stearic acid Nutrition 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-N Sulfurous acid Chemical compound OS(O)=O LSNNMFCWUKXFEE-UHFFFAOYSA-N 0.000 description 1
- FEWJPZIEWOKRBE-UHFFFAOYSA-N Tartaric acid Natural products [H+].[H+].[O-]C(=O)C(O)C(O)C([O-])=O FEWJPZIEWOKRBE-UHFFFAOYSA-N 0.000 description 1
- 229920000180 alkyd Polymers 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
- VZTDIZULWFCMLS-UHFFFAOYSA-N ammonium formate Chemical compound [NH4+].[O-]C=O VZTDIZULWFCMLS-UHFFFAOYSA-N 0.000 description 1
- 150000003863 ammonium salts Chemical class 0.000 description 1
- 229940101006 anhydrous sodium sulfite Drugs 0.000 description 1
- 229960005070 ascorbic acid Drugs 0.000 description 1
- WQZGKKKJIJFFOK-VFUOTHLCSA-N beta-D-glucose Chemical compound OC[C@H]1O[C@@H](O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-VFUOTHLCSA-N 0.000 description 1
- 229910000416 bismuth oxide Inorganic materials 0.000 description 1
- 239000003518 caustics Substances 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 239000003985 ceramic capacitor Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000013522 chelant Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 229910000431 copper oxide Inorganic materials 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
- 238000000280 densification Methods 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 239000003599 detergent Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- TYIXMATWDRGMPF-UHFFFAOYSA-N dibismuth;oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Bi+3].[Bi+3] TYIXMATWDRGMPF-UHFFFAOYSA-N 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 229920001249 ethyl cellulose Polymers 0.000 description 1
- 235000019325 ethyl cellulose Nutrition 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 235000019253 formic acid Nutrition 0.000 description 1
- 239000008103 glucose Substances 0.000 description 1
- 150000002429 hydrazines Chemical class 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical compound CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 description 1
- OQCDKBAXFALNLD-UHFFFAOYSA-N octadecanoic acid Natural products CCCCCCCC(C)CCCCCCCCC(O)=O OQCDKBAXFALNLD-UHFFFAOYSA-N 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000006479 redox reaction Methods 0.000 description 1
- XWGJFPHUCFXLBL-UHFFFAOYSA-M rongalite Chemical compound [Na+].OCS([O-])=O XWGJFPHUCFXLBL-UHFFFAOYSA-M 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- 239000012279 sodium borohydride Substances 0.000 description 1
- 229910000033 sodium borohydride Inorganic materials 0.000 description 1
- HLBBKKJFGFRGMU-UHFFFAOYSA-M sodium formate Chemical compound [Na+].[O-]C=O HLBBKKJFGFRGMU-UHFFFAOYSA-M 0.000 description 1
- 235000019254 sodium formate Nutrition 0.000 description 1
- 229910001379 sodium hypophosphite Inorganic materials 0.000 description 1
- 159000000000 sodium salts Chemical class 0.000 description 1
- GEHJYWRUCIMESM-UHFFFAOYSA-L sodium sulfite Chemical compound [Na+].[Na+].[O-]S([O-])=O GEHJYWRUCIMESM-UHFFFAOYSA-L 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000008117 stearic acid Substances 0.000 description 1
- 229940116411 terpineol Drugs 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
Landscapes
- Manufacture And Refinement Of Metals (AREA)
- Manufacture Of Metal Powder And Suspensions Thereof (AREA)
- Ceramic Capacitors (AREA)
- Fixed Capacitors And Capacitor Manufacturing Machines (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、還元析出法により
得られる銀粉の製造方法および当該方法により製造され
る銀粉に関する。詳しくは、コンデンサ用内部電極また
は回路基板導体パターンなどの電子部品に好適に使用さ
れる銀粉の製造方法および当該方法により製造される銀
粉に関する。[0001] The present invention relates to a method for producing silver powder obtained by a reduction precipitation method and a silver powder produced by the method. More specifically, the present invention relates to a method for producing silver powder suitably used for an electronic component such as an internal electrode for a capacitor or a conductor pattern of a circuit board, and a silver powder produced by the method.
【０００２】[0002]
【従来の技術】従来、積層コンデンサの内部電極または
回路導体パターンなどに、銀粉をガラスフリットととも
に有機ビヒクル中に加え混練して製造される銀ペースト
が使用されており、このようなペーストのための銀粉に
は、粒子径が適当に小さく、粒度が揃っていることが要
求されている。上記の銀粉の製造には、銀塩含有水溶液
にアルカリを加え、酸化銀を生成させ、さらに還元剤を
加えることで銀粉を製造する方法、もしくは銀塩含有水
溶液に錯化剤を加え錯体を生成させ、さらに還元剤を加
えることで銀粉を得る方法が用いられている。2. Description of the Related Art Conventionally, a silver paste manufactured by adding silver powder to an organic vehicle together with a glass frit and kneading it for an internal electrode or a circuit conductor pattern of a multilayer capacitor has been used. Silver powder is required to have a suitably small particle size and uniform particle size. In the production of the silver powder, a method of producing silver oxide by adding an alkali to a silver salt-containing aqueous solution to generate silver oxide and further adding a reducing agent, or adding a complexing agent to the silver salt-containing aqueous solution to form a complex And then adding a reducing agent to obtain silver powder.
【０００３】しかしながら、これらの方法で製造された
銀粉は凝集が激しく、ファインライン化が進む導体パタ
ーンや積層セラミックコンデンサの内部電極の薄膜化に
対応できないという欠点があった。そのため、得られる
銀粉をより凝集の少ないものとすべく改善が行われ、そ
れらの研究成果が例えば特開昭４９−１１３７５４号公
報、特開昭５２−５４６６１号公報、特開昭５４−１２
１２７０号公報および特開昭６１−２４３１０５号公報
などに開示されている。[0003] However, the silver powder produced by these methods has a problem that the silver powder is so agglomerated that it cannot cope with the thinning of the conductor pattern of fine lines and the internal electrodes of the multilayer ceramic capacitor. Therefore, improvements have been made to make the obtained silver powder less agglomerated, and the results of those studies have been described in, for example, JP-A-49-113754, JP-A-52-54661, and JP-A-54-12.
No. 1270 and Japanese Unexamined Patent Publication No. 61-243105.
【０００４】すなわち、特開昭４９−１１３７５４号公
報には、銀塩水溶液に苛性アルカリを加え、酸化銀を生
成させ、界面活性剤を加えて酸化銀を分散させた後に還
元する方法が開示され、酸化銀が生成したところで界面
活性剤を加えることで特性のばらつきの少ない均質な銀
粉が得られると記載されている。特開昭５２−５４６６
１号公報には、銀塩溶液をアミンの存在下でヒドラジン
で還元して銀粉を製造する際にアミンの種類および添加
量を変えることで銀粉の比表面積を調整する方法が開示
され、アミンの存在はヒドラジンの強い還元力を弱め不
均一反応を防止する効果があると記載されている。[0004] That is, JP-A-49-113754 discloses a method of adding a caustic alkali to a silver salt aqueous solution to generate silver oxide, adding a surfactant to disperse the silver oxide, and then reducing the silver oxide. It is described that when silver oxide is formed, a surfactant can be added to obtain a uniform silver powder with little variation in characteristics. JP-A-52-5466
No. 1 discloses a method of adjusting the specific surface area of silver powder by changing the type and amount of an amine when producing a silver powder by reducing a silver salt solution with hydrazine in the presence of an amine. It is described that the presence thereof has an effect of weakening the strong reducing power of hydrazine and preventing a heterogeneous reaction.
【０００５】特開昭５４−１２１２７０号公報には、硝
酸銀溶液とホルマリンの混合水溶液に析出銀量に対して
０．１〜５重量％の脂肪酸を添加攪拌し、これにアルカ
リ性溶液を添加して、銀粉末を析出させる方法が開示さ
れ、還元反応により銀微粒子が析出した時点で、脂肪酸
が銀微粒子を被覆することで微細で分散した銀粉が得ら
れると記載されている。特開昭６１−２４３１０５号公
報には、疎水性反応槽内で還元剤を用いてアンモニア性
硝酸銀錯体溶液を還元して、銀微粒子を製造する方法に
おいて、反応溶液中にカチオン系界面活性剤を添加する
ことで、単分散した銀微粒子を得る方法が開示され、疎
水性反応槽を使用する理由は、親水性の場合、析出反応
が容器の壁面で起こるために凝集した粒度分布の幅の広
い銀粒子しか得られないと記載している。また反応溶液
中にカチオン系界面活性剤を添加する理由は、アンモニ
ア性硝酸銀錯体溶液を還元することによって、水溶液中
に析出した銀微粒子が凝集しないで単分散状態を保つよ
うにするためと記載されている。この方法と同様にし
て、特開昭６１−２７６９０４号公報にはアニオン系界
面活性剤を、特開昭６１−２７６９０５号公報には、ノ
ニオン系界面活性剤を、特開昭６１−２７６９０６号公
報には両性界面活性剤を、特開昭６１−２７６９０７号
公報には保護コロイドを用いた方法が記載されている。Japanese Patent Application Laid-Open No. 54-212270 discloses that a fatty acid is added to a mixed aqueous solution of a silver nitrate solution and formalin in an amount of 0.1 to 5% by weight based on the amount of precipitated silver, followed by stirring. A method for depositing silver powder is disclosed, and it is described that when silver fine particles are precipitated by a reduction reaction, a fine and dispersed silver powder can be obtained by coating the silver fine particles with a fatty acid. Japanese Patent Application Laid-Open No. 61-243105 discloses a method for producing silver fine particles by reducing an ammoniacal silver nitrate complex solution using a reducing agent in a hydrophobic reaction tank. By adding, a method of obtaining monodispersed silver fine particles is disclosed, and the reason for using a hydrophobic reaction tank is that, in the case of hydrophilicity, the width of the particle size distribution that is aggregated because the precipitation reaction occurs on the wall surface of the container is wide. It states that only silver particles can be obtained. The reason for adding the cationic surfactant to the reaction solution is to reduce the ammoniacal silver nitrate complex solution so that the silver fine particles precipitated in the aqueous solution do not aggregate and remain in a monodispersed state. ing. In the same manner as in this method, JP-A-61-276904 discloses an anionic surfactant, JP-A-61-276905 discloses a nonionic surfactant, and JP-A-61-276906 discloses a nonionic surfactant. Describes a method using an amphoteric surfactant, and JP-A-61-276907 discloses a method using a protective colloid.
【０００６】[0006]
【発明が解決しようとする課題】しかしながら、このよ
うな従来技術の中には、界面活性剤や脂肪酸、アミン等
を反応液中に添加する方法となっていたため、特開昭４
９−１１３７５４号公報および特開昭６１−２４３１０
５号公報、特開昭６１−２７６９０４号公報から特開昭
６１−２７６９０７号公報の方法では、使用する界面活
性剤の種類によっては、反応溶液のｐＨや共存するイオ
ンにより、分散効果が不十分もしくは効果が現れない場
合があり、使用できる界面活性剤の種類が限定されてし
まい、また銀粉表面への厳密な被覆量を制御するのは困
難であり、特開昭５４−１２１２７０号公報の方法で
は、脂肪酸の添加量が多い場合に未還元反応になった
り、また分散剤が脂肪酸に限定されてしまい、特開昭５
２−５４６６１号公報の場合は、アミンの添加により比
表面積を調整する方法であり、分散性の良い銀粉は得ら
れないという課題があった。したがって本発明の目的
は、還元前に反応液に分散剤を加える従来の銀粉製造方
法のように、添加量によって未還元反応が生じたり分散
剤の種類、量が限定されたりすることがなく、しかも分
散性の優れた銀粉が得られる銀粉の製造方法とそれによ
り得られる銀粉を提供することにある。However, some of such prior arts involve a method of adding a surfactant, a fatty acid, an amine or the like to a reaction solution.
JP-A-9-113754 and JP-A-61-24310
No. 5, JP-A-61-276904 to JP-A-61-276907, the dispersing effect is insufficient due to the pH of the reaction solution or coexisting ions depending on the type of surfactant used. Alternatively, the effect may not be exhibited, the types of surfactants that can be used are limited, and it is difficult to control the strict amount of coating on the surface of silver powder. However, when a large amount of fatty acid is added, an unreduced reaction occurs, or the dispersant is limited to fatty acids.
In the case of Japanese Patent Application Laid-Open No. 2-54661, the specific surface area is adjusted by adding an amine, and there is a problem that silver powder having good dispersibility cannot be obtained. Therefore, the object of the present invention is that, unlike the conventional method for producing a silver powder in which a dispersant is added to a reaction solution before reduction, an unreduction reaction does not occur depending on the amount added, and the type and amount of the dispersant are not limited. Moreover, it is an object of the present invention to provide a method for producing silver powder from which silver powder having excellent dispersibility can be obtained, and a silver powder obtained by the method.
【０００７】[0007]
【課題を解決するための手段】本発明者らは上記目的を
達成するために鋭意研究した結果、銀錯体（銀塩）もし
くは酸化銀の一方または両者を含有する水溶液あるいは
水性懸濁液あるいは両者の混合体からなる水性反応系に
還元剤含有水溶液を加える際、還元された銀粒子の凝集
を防ぐために還元剤含有水溶液の添加速度を速くし、１
当量／分以上の速度で添加し、得られた銀粉含有スラリ
ーを濾過、水洗して含水率２０〜８０％のウエットケー
キとし、このウエットケーキを混合機中で混合砕解する
か、あるいは混合機中で分散剤とともに混合砕解すれ
ば、前記課題が解消されて優れた分散性を有する銀粉が
得られることを見いだし本発明に到達した。Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that an aqueous solution or aqueous suspension containing one or both of a silver complex (silver salt) and silver oxide or both. When the aqueous solution containing the reducing agent is added to the aqueous reaction system comprising the mixture of the above, the addition rate of the aqueous solution containing the reducing agent is increased in order to prevent aggregation of the reduced silver particles.
The obtained silver powder-containing slurry was filtered and washed with water to obtain a wet cake having a water content of 20 to 80%, and the wet cake was mixed and disintegrated in a mixer, or The present inventors have found that, if mixed and pulverized together with a dispersant therein, the above-mentioned problem is solved and a silver powder having excellent dispersibility can be obtained, and the present invention has been achieved.
【０００８】すなわち本発明は第１に、銀塩と酸化銀の
少なくとも一方を含有する水性反応系に還元剤含有水溶
液を添加し銀粒子を還元析出させる銀粉の製造方法にお
いて、銀粒子の還元析出後の析出銀粒子含有水性反応系
を濾過してウエットケーキとし、該ウエットケーキを砕
解することを特徴とする銀粉の製造方法：第２に、前記
ウエットケーキの含水率が２０〜８０％であることを特
徴とする前記第１記載の銀粉の製造方法：第３に、前記
ウエットケーキに分散剤を添加することを特徴とする前
記第１または第２のいずれかに記載の銀粉の製造方法：
第４に、前記分散剤として、脂肪酸、脂肪酸塩、界面活
性剤、有機金属、および保護コロイドのいずれか１種以
上が選択使用されることを特徴とする前記第３記載の銀
粉の製造方法：第５に、前記還元剤含有水溶液の添加速
度が含有銀量に対し１当量／分以上であることを特徴と
する前記第１〜第４のいずれかに記載の銀粉の製造方
法：第６に、前記第１〜第５のいずれかに記載の方法で
製造された銀粉であって、該銀粉のタップ密度が２ｇ／
ｃｍ3 以上、レーザー回折法平均粒径が０．１〜５μ
ｍ、かつ比表面積が５ｍ2 ／ｇ以下であることを特徴と
する銀粉：第７に、前記銀粉がペースト化された際、セ
ラミックス基板上に印刷された塗膜において、表面あら
さＲａが２μｍ以下、塗膜密度が４．５ｇ／ｃｍ3 以上
であり、かつ該塗膜を大気中で焼成して得られる焼成膜
において、表面あらさＲａが２μｍ以下、焼成膜密度が
１０ｇ／ｃｍ3 以上の特性をもたらす前記第６記載の銀
粉：第８に、前記第１〜第５のいずれかに記載の方法で
製造された銀粉を用いたペーストのセラミックス基板上
に印刷された塗膜において、表面あらさＲａが２μｍ以
下、塗膜密度が４．５ｇ／ｃｍ3 以上であり、かつ該塗
膜を大気中で焼成して得られる焼成膜において、表面あ
らさＲａが２μｍ以下、焼成膜密度が１０ｇ／ｃｍ3以
上となることを特徴とするペースト、を提供するもので
ある。That is, the present invention firstly provides a method for producing silver powder in which an aqueous solution containing a reducing agent is added to an aqueous reaction system containing at least one of a silver salt and silver oxide to reduce and precipitate silver particles. A method for producing silver powder, characterized in that the aqueous reaction system containing precipitated silver particles is filtered to obtain a wet cake, and the wet cake is crushed. Second, the wet cake has a water content of 20 to 80%. 3. The method for producing silver powder according to the first aspect, wherein a dispersant is added to the wet cake. :
Fourth, as the dispersant, any one or more of a fatty acid, a fatty acid salt, a surfactant, an organic metal, and a protective colloid is selectively used, wherein the method for producing silver powder according to the third aspect is as follows: Fifthly, the method for producing silver powder according to any one of the first to fourth aspects, wherein the rate of addition of the reducing agent-containing aqueous solution is 1 equivalent / minute or more with respect to the silver content: , A silver powder produced by the method according to any one of the first to fifth aspects, wherein the silver powder has a tap density of 2 g /
cm 3 or more, laser diffraction method average particle size is 0.1-5μ
and silver powder having a specific surface area of 5 m 2 / g or less: Seventh, when the silver powder is pasted, the surface roughness Ra of the coating film printed on the ceramic substrate is 2 μm or less. A film having a coating density of 4.5 g / cm 3 or more, and a fired film obtained by firing the coating in the air, having a surface roughness Ra of 2 μm or less and a fired film density of 10 g / cm 3 or more. Eighth, the silver powder according to the sixth aspect, wherein the silver powder produced by the method according to any one of the first to fifth aspects is coated on a ceramics substrate using a paste and has a surface roughness Ra. Is 2 μm or less, the coating density is 4.5 g / cm 3 or more, and the fired film obtained by firing the coating in the air has a surface roughness Ra of 2 μm or less and a fired film density of 10 g / cm 3. Characterized by the above Pastes.
【０００９】[0009]
【発明の実態の形態】本発明の製造方法の特徴は、還元
工程において銀イオン（銀塩）または酸化銀を含む水性
反応系に還元剤水溶液を１当量／分以上の速度で添加す
ること、あるいは反応系内における銀の還元反応すなわ
ち銀粉の生成反応が１分以内程度で終了するようにする
こと、および還元析出した銀粉を濾過水洗後、含水率２
０〜８０％のウエットケーキとして、乾燥せずに混合機
により砕解すること、さらに分散剤の添加は上記砕解の
際に添加することにある。本発明における製造方法で、
銀粉に還元する前の銀の形態は特に限定するものではな
い。具体的には、銀錯体塩含有水溶液の場合は硝酸銀水
溶液に錯化剤を加えて得られるので、錯化剤にはアンモ
ニア水、アンモニウム塩、キレート化合物等が使用でき
る。一方酸化銀含有水性懸濁液の場合は硝酸銀水溶液に
アルカリ例えば水酸化ナトリウム、水酸化カリウムなど
の水酸化物の添加により得ることができる。また、こう
して得られた銀錯体塩含有水溶液もしくは酸化銀含有水
性懸濁液を混合してから還元しても何ら差し支えない。A feature of the production method of the present invention is that a reducing agent aqueous solution is added at a rate of 1 equivalent / minute or more to an aqueous reaction system containing silver ions (silver salt) or silver oxide in the reduction step. Alternatively, the reduction reaction of silver in the reaction system, that is, the generation reaction of silver powder is completed within about 1 minute.
A wet cake of 0 to 80% is crushed by a mixer without drying, and the addition of a dispersant is to be added at the time of the crushing. In the production method of the present invention,
The form of silver before reduction to silver powder is not particularly limited. Specifically, an aqueous solution containing a silver complex salt is obtained by adding a complexing agent to an aqueous solution of silver nitrate, so that aqueous ammonia, an ammonium salt, a chelate compound or the like can be used as the complexing agent. On the other hand, a silver oxide-containing aqueous suspension can be obtained by adding an alkali such as sodium hydroxide or potassium hydroxide to a silver nitrate aqueous solution. The silver complex salt-containing aqueous solution or the silver oxide-containing aqueous suspension thus obtained may be mixed and then reduced.
【００１０】次に還元剤であるが、水溶液中の酸化還元
反応を利用して、銀粉を製造する公知の方法で用いる還
元剤であれば何ら問題はない。具体例としては、ヒドラ
ジン、ヒドラジン化合物、ホルマリン、ぶどう糖、水素
化ほう酸ナトリウム、次亜リン酸ナトリウム、亜硫酸
塩、ギ酸、ギ酸ナトリウム、無水亜硫酸ナトリウム、Ｌ
（＋）酒石酸、ギ酸アンモニウム、ロンガリット、Ｌ−
アスコルビン酸またはこれらの混合物である。そしてこ
れらの還元剤のうち固体状のものは水溶液として使用す
る。したがって使用の際には水溶液とした際に分解して
しまう物質については、溶液ｐＨをアルカリ側にするな
どの処理が必要である。還元時の温度については２０〜
８０℃の温度範囲で行うのが望ましい。還元剤の添加方
法については、銀粉の凝集を防ぐために、還元剤含有水
溶液を１当量／分以上の速さあるいは反応当量の還元剤
が１分以内に反応系全体に行きわたる速さで添加するよ
うにする。還元剤が添加される水性反応系の大きさが実
操業で使用する反応槽程度の大きさのものである限り、
その反応系の大きさによって厳密に添加速度を変更する
必要はなく１当量／分以上の速度で添加すれば効果があ
ることが確認された。この操作の理由は定かではない
が、還元剤を短時間で添加することで、銀粒子への還元
析出が一挙に生じ、短時間で還元反応が終了するために
発生した核同士の凝集が生じにくく、分散性が向上する
ものと考えられる。また還元の際には、より短時間で反
応が終了するように反応液を撹拌することが好ましい。The reducing agent is not a problem as long as it is a reducing agent used in a known method for producing silver powder by utilizing an oxidation-reduction reaction in an aqueous solution. Specific examples include hydrazine, hydrazine compounds, formalin, glucose, sodium borohydride, sodium hypophosphite, sulfite, formic acid, sodium formate, anhydrous sodium sulfite, L
(+) Tartaric acid, ammonium formate, Rongalit, L-
Ascorbic acid or a mixture thereof. Among these reducing agents, those in a solid state are used as an aqueous solution. Therefore, a substance which decomposes when used as an aqueous solution at the time of use requires a treatment such as adjusting the solution pH to an alkaline side. About the temperature at the time of reduction
It is desirable to carry out in a temperature range of 80 ° C. Regarding the method of adding the reducing agent, an aqueous solution containing the reducing agent is added at a rate of 1 equivalent / minute or more, or a reaction equivalent of the reducing agent is added within 1 minute to the entire reaction system in order to prevent aggregation of silver powder. To do. As long as the size of the aqueous reaction system to which the reducing agent is added is as large as the size of the reaction tank used in actual operation,
It was confirmed that there was no need to strictly change the addition rate depending on the size of the reaction system, and that the addition at a rate of 1 equivalent / min or more was effective. The reason for this operation is not clear, but by adding the reducing agent in a short time, reductive precipitation on the silver particles occurs at a stroke, and the reduction reaction is completed in a short time, resulting in the aggregation of nuclei generated. It is considered that the dispersibility is difficult to improve. In the case of reduction, the reaction solution is preferably stirred so that the reaction is completed in a shorter time.
【００１１】還元、析出により得られた銀粉含有水溶液
は、濾過水洗により銀粉からなる含水率２０〜８０％の
ウエットケーキとする。濾過の方法は固液分離に使用さ
れる方法であれば問題ない。例を挙げると遠心濾過機、
フィルタープレス、ブフナー漏斗などである。ウェット
ケーキの含水率を２０〜８０％と限定した理由は、含水
率２０％未満であると得られるケーキが固くなり、後工
程の砕解が効率悪くなるためであり、含有率８０％を越
えても、後工程の砕解が効率が下がるためである。こう
して得たウェットケーキ混合機により砕解する工程に通
すことより、分散性の優れた銀粉が得られる。分散剤を
添加しても添加しなくてもよいが、分散剤を添加混合す
ることにより分散効果が大きくなり、より好ましい結果
を得ることができる。The aqueous solution containing silver powder obtained by reduction and precipitation is filtered and washed with water to form a wet cake of silver powder having a water content of 20 to 80%. There is no problem if the method of filtration is a method used for solid-liquid separation. For example, a centrifugal filter,
Filter press, Buchner funnel, etc. The reason why the water content of the wet cake is limited to 20 to 80% is that if the water content is less than 20%, the obtained cake becomes hard and the disintegration in the subsequent step becomes inefficient, and the content exceeds 80%. However, this is because the efficiency of the subsequent disintegration decreases. Silver powder with excellent dispersibility can be obtained by passing it through the step of pulverization by the wet cake mixer thus obtained. The dispersing agent may or may not be added, but by adding and mixing the dispersing agent, the dispersing effect increases, and more preferable results can be obtained.
【００１２】ここで使用する混合機には、固液混合に使
用される混合機か固体の粉砕に使用される混合粉砕機な
どがある。ここで使用する分散剤の種類については、あ
らゆる種類が使用できるが、好適に用いることができる
のは、脂肪酸、脂肪酸塩、脂肪酸または脂肪酸塩のエマ
ルジョン、陽イオン界面活性剤、陰イオン界面活性剤、
両性界面活性剤、非イオン性界面活性剤、有機金属、保
護コロイドのいずれかであり、１種以上選択できる。添
加量については特に限定するものではなく、銀粉の用途
に合わせ適量添加すればよい。混合機により砕解された
ウェットケーキは、濃度の高い銀粉含有スラリーとなっ
ており、さらにこれを濾過、水洗することで、分散剤で
表面が被覆された銀粉ウェットケーキが得られる。濾
過、水洗の方法は先にも述べた通り、通常の固液分離に
使用する装置を用いれば何ら問題はない。こうして得ら
れた銀粉ウェットケーキは乾燥工程を経て銀粉となる。
乾燥方法については公知の方法および設備を用いれば良
く、雰囲気も特に限定されるものではない。乾燥温度は
８０℃以下が好ましい。The mixer used here includes a mixer used for solid-liquid mixing and a mixing pulverizer used for pulverizing solids. As for the kind of the dispersant used here, any kind can be used, but preferably used are fatty acid, fatty acid salt, emulsion of fatty acid or fatty acid salt, cationic surfactant, anionic surfactant ,
One of an amphoteric surfactant, a nonionic surfactant, an organic metal, and a protective colloid, and one or more types can be selected. The amount added is not particularly limited, and may be added in an appropriate amount according to the use of the silver powder. The wet cake pulverized by the mixer is a silver powder-containing slurry having a high concentration, and is further filtered and washed with water to obtain a silver powder wet cake whose surface is coated with a dispersant. As described above, there is no problem in the method of filtration and water washing as long as an apparatus used for ordinary solid-liquid separation is used. The silver powder wet cake thus obtained is converted into silver powder through a drying step.
A known method and equipment may be used for the drying method, and the atmosphere is not particularly limited. The drying temperature is preferably 80 ° C. or lower.
【００１３】これら工程を通して製造された銀粉は、タ
ップ密度が２ｇ／ｃｍ3 以上、レーザー回折法による平
均粒径が０．１〜５μｍ、比表面積が５ｍ2 ／ｇ以下の
物性を有するものである。タップ密度はＪＩＳ Ｋ５１
０１−１９９１の２０．２のタップ法に準じた方法によ
り測定した。タッピング回数は１，０００回である。従
来方法により製造した銀粉は分散性が不十分であり、こ
の方法で測定したタップ密度は２ｇ／ｃｍ 3 未満である
のに対し、本発明により得られる銀粉は単分散により近
い状態のためタップ密度は２ｇ／ｃｍ3 以上となる。銀
粉の平均粒径については、レーザー回折法により測定し
ており、装置は島津製作所製レーザー回折式粒度測定機
ＳＡＬＤ−１１００を用いた。分散媒は、ヘキサメタリ
ン酸ナトリウムを蒸留水に溶解し、０．２％水溶液とし
て用いた。また測定時に分散媒５０ｍｌ当り１滴の家庭
用液体洗剤を加えている。測定時の屈折率はＡ３であ
る。この方法で測定した場合、本発明により得られた銀
粉は平均粒径０．１〜５μｍとなるのに対し、従来法に
よる銀粉は５μｍを越える値となり分散性が劣ってい
る。比表面積はＢＥＴ法で測定した。本発明法で製造し
た銀粉は５ｍ2 ／ｇ以下となる。上記特性を持つ銀粉
を、その主用途であるペーストとして評価すると、その
銀粉の優れた面を知ることができる。The silver powder produced through these steps is
Top density is 2g / cmThreeAbove, flat by laser diffraction method
Uniform particle size: 0.1-5 μm, specific surface area: 5 mTwo/ G or less
It has physical properties. Tap density is JIS K51
By a method according to the tap method of 20.2 of 01-1991.
Measured. The number of tappings is 1,000. Obedience
Silver powder produced by the conventional method has insufficient dispersibility,
Tap density measured by the method of 2 g / cm ThreeIs less than
On the other hand, the silver powder obtained by the present invention is closer to monodispersion.
Tap density is 2g / cmThreeThat is all. Silver
The average particle size of the powder is measured by the laser diffraction method.
The equipment is a laser diffraction type particle sizer manufactured by Shimadzu Corporation
SALD-1100 was used. The dispersing medium is hexametallic
Sodium salt dissolved in distilled water to make a 0.2% aqueous solution
Used. In addition, at the time of measurement, one drop of
Liquid detergent is added. The refractive index at the time of measurement is A3
You. When measured by this method, the silver obtained by the present invention
While the powder has an average particle size of 0.1 to 5 μm, the conventional method
Silver powder has a value exceeding 5 μm, and dispersibility is poor.
You. The specific surface area was measured by the BET method. Manufactured by the method of the present invention.
Silver powder is 5mTwo/ G or less. Silver powder with the above characteristics
Is evaluated as its main use paste,
You can know the excellent aspect of silver powder.
【００１４】ペースト化の方法については、公知の例に
従って実施すれば、特に問題はない。ここではハイブリ
ッドＩＣなどの導体パターン形成に使用される厚膜銀ペ
ーストを例とする。まずペーストに使用するビヒクルで
あるが、一般的には各種セルロース、アクリル樹脂、フ
ェノール樹脂、アルキッド樹脂などを、アルコール系、
エステル系、エーテル系、炭化水素等の溶剤に溶解した
ものが用いられる。また導体パターンとアルミナ基板な
どのセラミック基板を結着するために、各種無機バイン
ダーがペーストに添加される。無機バインダーとして
は、酸化銅、酸化ビスマスといった金属酸化物や、ガラ
スを微細に粉砕したガラスフリットといわれるものが用
いられる。There is no particular problem for the method of pasting if it is carried out according to a known example. Here, a thick-film silver paste used for forming a conductor pattern such as a hybrid IC is taken as an example. First of all, it is a vehicle used for paste, but in general, various kinds of cellulose, acrylic resin, phenol resin, alkyd resin, etc.
Those dissolved in solvents such as ester, ether, and hydrocarbon are used. In addition, various kinds of inorganic binders are added to the paste in order to bond the conductor pattern to a ceramic substrate such as an alumina substrate. As the inorganic binder, a metal oxide such as copper oxide or bismuth oxide, or a so-called glass frit obtained by finely pulverizing glass is used.
【００１５】評価のための試験においては、上記ペース
ト構成物の多くの組み合わせの中より、極く一般的な組
成でペーストを調製し、銀粉の評価を行った。ビヒクル
は４５ｃｐのエチルセルロースをターピネオールに溶解
し、１０％溶液を調製した。このビヒクルと日本電気ガ
ラス製ＧＡ−８ガラス粉および銀粉を次の組成となるよ
うに秤量する。 ビヒクルは３７．４％、銀粉６１％、６Ａ−８ガラス粉
１．６％ これらペースト構成物をビーカー中で予備混合後、３本
ロールにて分散、ペーストを得る。図１は銀粉のペース
ト化後の印刷方法を示した斜視図で、同図ａはメンディ
ングテープを貼った基板上にペーストを引き延ばしてＥ
Ｄ印刷する様子を、同図ｂは基板上に印刷されたペース
ト塗膜を示す。すなわち、このペースト３をメンディン
グテープ２を一定間隔で平行に貼った９６％アルミナ基
板１上に盛り、ガラス棒４でペーストを引き延ばして印
刷し、テープ剥離後、ペースト塗膜５を１０分間のレべ
リング後、熱風循環乾燥機で１５０℃、１０分の乾燥を
行う。In a test for evaluation, a paste having an extremely general composition was prepared from among many combinations of the above-mentioned paste components, and silver powder was evaluated. As a vehicle, 45 cp of ethyl cellulose was dissolved in terpineol to prepare a 10% solution. The vehicle, GA-8 glass powder and silver powder made by NEC Corporation are weighed to have the following composition. Vehicle: 37.4%, silver powder: 61%, 6A-8 glass powder: 1.6% These paste components are premixed in a beaker, and then dispersed with a three-roll mill to obtain a paste. FIG. 1 is a perspective view showing a printing method after the silver powder is made into a paste. FIG.
FIG. 2B shows the paste coating printed on the substrate in the state of D printing. That is, the paste 3 was placed on a 96% alumina substrate 1 on which a mending tape 2 was stuck in parallel at regular intervals, the paste was stretched and printed with a glass rod 4, and after the tape was peeled off, the paste coating 5 was applied for 10 minutes. After leveling, drying is performed at 150 ° C. for 10 minutes using a hot air circulation dryer.
【００１６】乾燥させた塗膜は次の方法により評価し
た。表面あらさは触針式表面あらさ計で測定できるが、
ここでは（株）ミツトヨ製Ｓｕｒｆｔｅｓｔ−５０１を
用いて測定した。測定モードはＲａとし、測定レンジ８
０μｍ、カットオフ値０．３ｍｍ、測定区間３とした。
塗膜密度は次の方法により測定した。塗膜の厚さは日本
真空技術株式会社製ＤＥＫＴＡＫIIＡ表面あらさ計によ
り測定したが、同様の測定機構を持つ装置であれば問題
はない。塗膜の幅と長さはノギスにより測定した。塗膜
の重さは印刷前に基板の重さを測定しておき、ペースト
を印刷、乾燥後の（基板＋塗膜）の重さを測定し、それ
らの差から求めた。そして次式により塗膜密度を求め
た。 Ｄ＝（ｗ2 −ｗ1 ）／Ａ×Ｂ×Ｔ ここではＤは塗膜密度（ｇ／ｃｍ3 ）、ｗ1 は基板の重
さ（ｇ）、ｗ2 は（基板＋塗膜）の重さ（ｇ）、Ａは塗
膜の幅（ｃｍ）、Ｂは塗膜の長さ（ｃｍ）、Ｔは塗膜の
厚さ（ｃｍ）である。The dried coating film was evaluated by the following method. Surface roughness can be measured with a stylus-type surface roughness meter,
Here, it measured using Surftest-501 made by Mitutoyo Corporation. The measurement mode is Ra and the measurement range is 8
0 μm, cutoff value 0.3 mm, and measurement section 3 were set.
The coating density was measured by the following method. The thickness of the coating film was measured with a DEKTAKIIA surface roughness meter manufactured by Japan Vacuum Engineering Co., Ltd. However, there is no problem as long as the device has a similar measuring mechanism. The width and length of the coating film were measured with a caliper. The weight of the coating film was determined by measuring the weight of the substrate before printing, measuring the weight of (substrate + coating film) after printing and drying the paste, and determining the difference between them. Then, the coating density was determined by the following equation. D = (w 2 −w 1 ) / A × B × T Here, D is the coating density (g / cm 3 ), w 1 is the weight of the substrate (g), and w 2 is the weight of the (substrate + coating). Weight (g), A is the width (cm) of the coating, B is the length (cm) of the coating, and T is the thickness (cm) of the coating.
【００１７】これらの方法により銀粉を評価したところ
次のことを見いだした。分散性の優れた銀粉を用いたペ
ーストの塗膜はＲａが２μｍ以下となり、特に優れた銀
粉は０．７μｍ以下と小さい値を示し、かつ塗膜密度Ｄ
は４．５ｇ／ｃｍ3 以上の値を示し、緻密な塗膜になる
のである。このように緻密でしかも表面が滑らかな塗膜
は、タップ密度２ｇ／ｃｍ3 以上、レーザー回折法によ
る平均粒径０．１〜５μｍで、比表面積５ｍ2 ／ｇ以下
の銀粉から得られることは言うまでもない。また、この
ような特性を持つ塗膜は焼成により銀導体パターンとし
た際にも、優れた特性を示すことを見いだした。この塗
膜に、大気中でベルト炉により８５０℃、７分の焼成を
施し、焼成膜を得る。そして塗膜と同様の方法により、
焼成膜の表面あらさＲａ、焼成膜密度を測定した。その
結果、焼成膜Ｒａは２μｍ以下で、特に分散性の優れた
銀粉を用いた場合、０．８μｍ以下となった。また焼成
膜密度においても１０ｇ／ｃｍ3以上の緻密な膜を得る
ことができる。When silver powder was evaluated by these methods, the following was found. The coating film of the paste using the silver powder having excellent dispersibility has a Ra of 2 μm or less, the particularly excellent silver powder has a small value of 0.7 μm or less, and the coating density D
Shows a value of 4.5 g / cm 3 or more, and a dense coating film is obtained. Such a dense and smooth surface coating film can be obtained from silver powder having a tap density of 2 g / cm 3 or more, an average particle diameter of 0.1 to 5 μm by a laser diffraction method, and a specific surface area of 5 m 2 / g or less. Needless to say. Further, it has been found that a coating film having such characteristics exhibits excellent characteristics even when formed into a silver conductor pattern by firing. This coating film is fired at 850 ° C. for 7 minutes in a belt furnace in the atmosphere to obtain a fired film. And by the same method as the coating film,
The surface roughness Ra of the fired film and the density of the fired film were measured. As a result, the calcined film Ra was 2 μm or less, and particularly 0.8 μm or less when silver powder having excellent dispersibility was used. Further, a dense film having a fired film density of 10 g / cm 3 or more can be obtained.
【００１８】このように、塗膜密度が高く、焼成膜密度
も高くなる銀粉を用いることは、焼成によるパターンの
収縮率の低減または各種基板や素材との収縮率の整合性
を高め、その結果として得られる応用製品の歩留りの上
昇と高特性化に大きく寄与することとなり、銀粉の分散
剤の種類、添加量によりペースト塗膜の収縮率を制御で
きる点も本発明の製造方法の特徴であり、銀粉の特徴で
もある。以下実施例により本発明をさらに詳細に説明す
る。しかし本発明の範囲は以下の実施例により制限され
るものではない。As described above, the use of silver powder having a high coating film density and a high fired film density can reduce the contraction rate of the pattern due to the firing or increase the consistency of the contraction rate with various substrates and materials. It is also a feature of the manufacturing method of the present invention that it greatly contributes to the increase in the yield and the improvement of the properties of the applied product obtained as a type, and the type of the dispersant of the silver powder, the shrinkage of the paste coating film can be controlled by the amount added. It is also a characteristic of silver powder. Hereinafter, the present invention will be described in more detail by way of examples. However, the scope of the present invention is not limited by the following examples.
【００１９】[0019]
【実施例１】銀イオンとして２０ｇ／ｌの硝酸銀水溶液
２０００ｍｌに、２５％アンモニア水１５０ｍｌを加
え、銀アンミン錯体水溶液を得た。この水溶液を液温２
０℃とし、攪拌しながら３７％ホルマリン水溶液４５ｍ
ｌを４０秒間で加え、銀粉を析出させ銀粉含有スラリー
を得た。このスラリーをブフナー漏斗で濾過水洗し、含
水率５５％のウェットケーキを得た。このウエットケー
キと銀粉の重量に対して１％分の東邦化学工業（株）会
社製非イオン性陰イオン界面活性剤ＧＡＦＡＣＲＡ−６
００を卓上ブレンダーミル内で約６０秒混合砕解した、
その後、再びブフナー漏斗にて濾過、水洗し、さらに大
気中７０℃、２４時間乾燥して銀粉を得た。得られた銀
粉はタップ密度２．８ｇ／ｃｍ3 、レーザー回折法平均
粒径３．０μｍ、比表面積０．７ｍ2 ／ｇであった。さ
らにこの粉末をペースト化し、評価を行った。方法は前
項「発明の実施の形態」の項で記述した方法である。そ
の結果、塗膜密度は４．７ｇ／ｃｍ3 、塗膜Ｒａ＝１．
７μｍ、焼成膜密度１０．５ｇ／ｃｍ3 、焼成膜Ｒａ＝
１．３５μｍで、塗膜密度、焼成膜密度とも良好な結果
が得られた。Example 1 150 ml of 25% aqueous ammonia was added to 2000 ml of a 20 g / l silver nitrate aqueous solution as silver ions to obtain a silver ammine complex aqueous solution. This aqueous solution is heated at a liquid temperature of 2
0 ° C, 37% formalin aqueous solution 45m with stirring
1 was added over 40 seconds to precipitate silver powder, thereby obtaining a silver powder-containing slurry. The slurry was filtered and washed with a Buchner funnel to obtain a wet cake having a water content of 55%. GAFACRA-6, a nonionic anionic surfactant manufactured by Toho Chemical Industry Co., Ltd. in an amount of 1% based on the weight of the wet cake and the silver powder.
00 was mixed and disintegrated for about 60 seconds in a tabletop blender mill,
Thereafter, the mixture was filtered again with a Buchner funnel, washed with water, and dried in air at 70 ° C. for 24 hours to obtain silver powder. The obtained silver powder had a tap density of 2.8 g / cm 3 , an average particle size of 3.0 μm by a laser diffraction method, and a specific surface area of 0.7 m 2 / g. Further, this powder was made into a paste and evaluated. The method is the method described in the section “Embodiments of the Invention” in the previous section. As a result, the coating density was 4.7 g / cm 3 , and the coating Ra = 1.
7 μm, fired film density 10.5 g / cm 3 , fired film Ra =
At 1.35 μm, good results were obtained in both the coating film density and the fired film density.
【００２０】[0020]
【実施例２】銀イオン濃度として８０ｇ／ｌの硝酸銀水
溶液２０００ｍｌを温度２５℃とした後に、攪拌しなが
ら、１００ｇ／ｌの水酸化ナトリウム水溶液８００ｍｌ
を加え、酸化銀スラリーを得た。このスラリーに３７％
ホルマリン溶液１４０ｍｌを５０秒間で添加して銀粒子
へ還元し、得られた銀粉含有スラリーをブフナー漏斗で
濾過、水洗し、含水率４０％のウェットケーキを得た。
次いで中京油脂（株）会社製のステアリン酸をエマルジ
ョン化したセロゾール９２０を銀量に対し、１重量％分
用意し、先のウェットケーキとともに卓上ブレンダーミ
ル内で６０秒混合砕解した。こうして得た混合物をブフ
ナー漏斗で濾過、水洗し、大気中で７０℃２４時間の乾
燥を行った。得られた銀粉はタップ密度３．２ｇ／ｃｍ
3 、レーザー回折法平均粒径１．０μｍ、比表面積１．
５ｍ2 ／ｇで分散性に優れたものであった。さらにこの
粉末をペースト化し評価を行った。方法は前項「発明の
実施の形態」の項で記述した方法である。その結果、塗
膜密度は５．３ｇ／ｃｍ3 、塗膜Ｒａ＝０．５μｍ、焼
成膜密度１０．７ｇ／ｃｍ3 、焼成膜Ｒａ＝０．４μｍ
という緻密で表面平滑性に優れたものであった。Example 2 An aqueous silver nitrate solution having a silver ion concentration of 80 g / l in 2000 ml was heated to a temperature of 25 ° C., and then stirred, 800 ml of a 100 g / l aqueous sodium hydroxide solution was stirred.
Was added to obtain a silver oxide slurry. 37% in this slurry
Formalin solution (140 ml) was added for 50 seconds to reduce silver particles, and the obtained silver powder-containing slurry was filtered with a Buchner funnel and washed with water to obtain a wet cake having a water content of 40%.
Then, 1 wt% of Cellosol 920 emulsified with stearic acid manufactured by Chukyo Yushi Co., Ltd. was prepared based on the silver amount, and mixed and pulverized together with the wet cake in a tabletop blender mill for 60 seconds. The mixture thus obtained was filtered through a Buchner funnel, washed with water, and dried in air at 70 ° C. for 24 hours. The obtained silver powder has a tap density of 3.2 g / cm.
3. Laser diffraction average particle size 1.0 μm, specific surface area 1.
At 5 m 2 / g, the dispersibility was excellent. Further, this powder was made into a paste and evaluated. The method is the method described in the section “Embodiments of the Invention” in the previous section. As a result, the coating film density was 5.3 g / cm 3 , the coating film Ra = 0.5 μm, the fired film density was 10.7 g / cm 3 , and the fired film Ra was 0.4 μm.
It was dense and excellent in surface smoothness.
【００２１】[0021]
【比較例】銀イオン濃度として６０ｇ／ｌの硝酸銀水溶
液２０００ｍｌを温度２５℃として、２００ｇ／ｌの水
酸化ナトリウム６００ｍｌを加え、酸化銀スラリーを得
た。さらに３７％ホルマリン溶液１４０ｍｌを１４ｍｌ
／ｍｉｎの添加速度で１０分間加え酸化銀粒子を銀粒子
へ還元した。その後、ブフナー漏斗で濾過、水洗し、７
０℃、２４時間の乾燥を行い、銀粉を得た。こうして得
られた銀粉はタップ密度１．０ｇ／ｃｍ3 、レーザー回
折法平均粒径１５．０μｍ、比表面積０．９ｍ2 ／ｇで
分散性の劣るものであった。この銀粉を実施例と同じ方
法でペースト化し、評価したところ、、塗膜密度は３．
０ｇ／ｃｍ3 、塗膜Ｒａ＝２．５μｍ、焼成膜密度７．
５ｇ／ｃｍ3 、焼成膜Ｒａ＝２．１μｍと緻密化の進ん
でいない状態であった。COMPARATIVE EXAMPLE A silver oxide slurry was obtained by adding 2,000 ml of an aqueous silver nitrate solution having a silver ion concentration of 60 g / l to a temperature of 25 ° C. and adding 600 ml of 200 g / l sodium hydroxide. 14 ml of 37% formalin solution 140 ml
The silver oxide particles were reduced to silver particles by adding for 10 minutes at an addition rate of / min. Then, the mixture was filtered with a Buchner funnel, washed with water,
Drying was performed at 0 ° C. for 24 hours to obtain silver powder. The silver powder thus obtained had a tap density of 1.0 g / cm 3 , a laser diffraction average particle size of 15.0 μm, and a specific surface area of 0.9 m 2 / g, and had poor dispersibility. When this silver powder was pasted and evaluated in the same manner as in the example, the coating density was 3.
0 g / cm 3 , coating Ra = 2.5 μm, fired film density 7.
5 g / cm 3 , the baked film Ra = 2.1 μm, indicating that densification had not progressed.
【００２２】[0022]
【発明の効果】以上説明したように、還元前に反応液に
分散剤を添加する従来法では添加量によって未還元反応
を生じる場合があり、分散剤の種類、量が限定されてし
まうのにの対し、本発明の方法によれば、還元剤含有水
溶液の添加速度を１当量／分以上とし、得られた銀粉含
有スラリーを濾過、水洗して含水率２０〜８０％のウエ
ットケーキとし、これを混合機中で混合砕解するか、混
合機中で分散剤とともに混合砕解するので、分散性に優
れた銀粉がえられ、ペースト化して回路基板の導体パタ
ーン等に好適な塗膜または焼成膜とすることができる。As described above, in the conventional method in which a dispersant is added to a reaction solution before reduction, an unreduced reaction may occur depending on the amount of the dispersant, and the type and amount of the dispersant are limited. On the other hand, according to the method of the present invention, the addition rate of the reducing agent-containing aqueous solution is set to 1 equivalent / min or more, and the obtained silver powder-containing slurry is filtered and washed with water to obtain a wet cake having a water content of 20 to 80%. Is mixed and disintegrated in a mixer, or mixed and disintegrated with a dispersing agent in the mixer, so that silver powder having excellent dispersibility is obtained, and is formed into a paste and is suitable for a conductive pattern or the like of a circuit board. It can be a membrane.
【図１】銀粉のペースト化後の印刷方法を示した斜視図
で、同図ａはメンディングテープを一定間隔で平行に貼
った基板上にペーストを引き延ばして印刷する様子を、
同図ｂは基板上に印刷された塗膜を示す図である。FIG. 1 is a perspective view showing a printing method after a silver powder is made into a paste. FIG. 1a shows a state in which a paste is stretched and printed on a substrate on which a mending tape is attached in parallel at regular intervals.
FIG. 2B is a diagram showing a coating film printed on the substrate.
１ ９６％アルミナ基板 ２ メンディングテープ ３ ペースト ４ ガラス棒 ５ ペースト塗膜 1 96% alumina substrate 2 Mending tape 3 Paste 4 Glass rod 5 Paste coating
───────────────────────────────────────────────────── フロントページの続き (72)発明者 板橋 利宗 東京都千代田区丸の内１丁目８番２号 同 和ケミカル株式会社内 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Toshimune Itabashi 1-8-2 Marunouchi, Chiyoda-ku, Tokyo Dowa Chemical Co., Ltd.
Claims (8)
る水性反応系に還元剤含有水溶液を添加し銀粒子を還元
析出させる銀粉の製造方法において、銀粒子の還元析出
後の析出銀粒子含有水性反応系を濾過してウエットケー
キとし、該ウエットケーキを砕解することを特徴とする
銀粉の製造方法。1. A method for producing silver powder in which an aqueous solution containing a reducing agent is added to an aqueous reaction system containing at least one of a silver salt and silver oxide to reduce and deposit silver particles. A method for producing silver powder, comprising filtering an aqueous reaction system into a wet cake, and pulverizing the wet cake.
０％であることを特徴とする請求項１記載の銀粉の製造
方法。2. The wet cake according to claim 1, wherein said wet cake has a water content of 20 to 8 or more.
The method for producing silver powder according to claim 1, wherein the content is 0%.
ことを特徴とする請求項１または２のいずれかに記載の
銀粉の製造方法。3. The method for producing silver powder according to claim 1, wherein a dispersant is added to the wet cake.
界面活性剤、有機金属、および保護コロイドのいずれか
１種以上が選択使用されることを特徴とする請求項３記
載の銀粉の製造方法。4. As the dispersant, a fatty acid, a fatty acid salt,
4. The method for producing silver powder according to claim 3, wherein at least one of a surfactant, an organic metal, and a protective colloid is selectively used.
銀量に対し１当量／分以上であることを特徴とする請求
項１〜４のいずれかに記載の銀粉の製造方法。5. The method for producing silver powder according to claim 1, wherein the rate of addition of the reducing agent-containing aqueous solution is 1 equivalent / minute or more with respect to the silver content.
製造された銀粉であって、該銀粉のタップ密度が２ｇ／
ｃｍ3 以上、レーザー回折法平均粒径が０．１〜５μ
ｍ、かつ比表面積が５ｍ2 ／ｇ以下であることを特徴と
する銀粉。6. A silver powder produced by the method according to claim 1, wherein the silver powder has a tap density of 2 g / g.
cm 3 or more, laser diffraction method average particle size is 0.1-5μ
m and a specific surface area of 5 m 2 / g or less.
ックス基板上に印刷された塗膜において、表面あらさＲ
ａが２μｍ以下、塗膜密度が４．５ｇ／ｃｍ3 以上であ
り、かつ該塗膜を大気中で焼成して得られる焼成膜にお
いて、表面あらさＲａが２μｍ以下、焼成膜密度が１０
ｇ／ｃｍ3 以上の特性をもたらす請求項６記載の銀粉。7. When the silver powder is made into a paste, the coating film printed on the ceramic substrate has a surface roughness R.
a is 2 μm or less, the coating density is 4.5 g / cm 3 or more, and the fired film obtained by firing the coating in the air has a surface roughness Ra of 2 μm or less and a fired film density of 10
7. The silver powder according to claim 6, which provides a property of g / cm < 3 > or more.
製造された銀粉を用いたペーストであって、該ペースト
のセラミックス基板上に印刷された塗膜において、表面
あらさＲａが２μｍ以下、塗膜密度が４．５ｇ／ｃｍ3
以上であり、かつ該塗膜を大気中で焼成して得られる焼
成膜において、表面あらさＲａが２μｍ以下、焼成膜密
度が１０ｇ／ｃｍ3 以上となることを特徴とするペース
ト。8. A paste using silver powder produced by the method according to claim 1, wherein the paste has a surface roughness Ra of 2 μm or less in a coating film printed on a ceramic substrate. , The coating density is 4.5 g / cm 3
A paste characterized in that a fired film obtained by firing the coating film in the air has a surface roughness Ra of 2 μm or less and a fired film density of 10 g / cm 3 or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26360196A JP4012960B2 (en) | 1996-09-12 | 1996-09-12 | Silver powder manufacturing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26360196A JP4012960B2 (en) | 1996-09-12 | 1996-09-12 | Silver powder manufacturing method |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2007061206A Division JP2007224422A (en) | 2007-03-12 | 2007-03-12 | Silver powder and paste using the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH1088207A true JPH1088207A (en) | 1998-04-07 |
| JP4012960B2 JP4012960B2 (en) | 2007-11-28 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP26360196A Expired - Lifetime JP4012960B2 (en) | 1996-09-12 | 1996-09-12 | Silver powder manufacturing method |
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|---|---|---|---|---|
| JP2000129318A (en) * | 1998-10-22 | 2000-05-09 | Dowa Mining Co Ltd | Silver powder and its production |
| WO2001048762A1 (en) * | 1999-12-24 | 2001-07-05 | Ngk Insulators, Ltd. | Ceramic capacitor electrode-forming paste |
| WO2002013999A1 (en) * | 2000-08-11 | 2002-02-21 | Ishihara Sangyo Kaisha, Ltd. | Colloidal metal solution, process for producing the same, and coating material containing the same |
| WO2005099939A1 (en) * | 2004-04-14 | 2005-10-27 | Mitsui Mining & Smelting Co., Ltd. | Silver powder coated with silver compound and manufacturing method thereof |
| JP2006152327A (en) * | 2004-11-25 | 2006-06-15 | Dowa Mining Co Ltd | Silver powder and production method therefor |
| JP2007016258A (en) * | 2005-07-05 | 2007-01-25 | Mitsui Mining & Smelting Co Ltd | High crystal silver powder, and method for producing the high crystal silver powder |
| JP2007220332A (en) * | 2006-02-14 | 2007-08-30 | Dowa Holdings Co Ltd | Silver powder and its manufacturing method, paste, electronic circuit component, and electric product using the same |
| JP2009242914A (en) * | 2008-03-31 | 2009-10-22 | Mitsui Mining & Smelting Co Ltd | Flake silver powder, and method for producing the same |
| JP2012153979A (en) * | 2012-04-02 | 2012-08-16 | Dowa Holdings Co Ltd | Silver powder and method for production thereof |
| CN103100722A (en) * | 2013-01-30 | 2013-05-15 | 广东羚光新材料股份有限公司 | Preparation method of high tap density monodisperse silver powder |
| CN106825544A (en) * | 2017-02-17 | 2017-06-13 | 江苏欧耐尔新型材料股份有限公司 | Improve the high-specific surface area silver powder and preparation method of electrode of solar battery electric conductivity |
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| US10807161B2 (en) | 2014-09-29 | 2020-10-20 | Dowa Electronics Materials Co., Ltd. | Silver powder, method for producing same, and hydrophilic conductive paste |
| CN111889695A (en) * | 2020-07-15 | 2020-11-06 | 善日(嘉善)能源科技有限公司 | Preparation method of micro-nano silver powder with controllable particle size |
| CN113399679A (en) * | 2021-05-08 | 2021-09-17 | 东方电气集团科学技术研究院有限公司 | Preparation method of high-tap aging-resistant superfine silver powder for electronic paste |
| WO2021193575A1 (en) * | 2020-03-24 | 2021-09-30 | Ｄｏｗａエレクトロニクス株式会社 | Method for producing silver powder |
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1996
- 1996-09-12 JP JP26360196A patent/JP4012960B2/en not_active Expired - Lifetime
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| JP2000129318A (en) * | 1998-10-22 | 2000-05-09 | Dowa Mining Co Ltd | Silver powder and its production |
| WO2001048762A1 (en) * | 1999-12-24 | 2001-07-05 | Ngk Insulators, Ltd. | Ceramic capacitor electrode-forming paste |
| US6565774B2 (en) | 1999-12-24 | 2003-05-20 | Ngk Insulators, Ltd. | Paste for formation of ceramic capacitor electrode |
| WO2002013999A1 (en) * | 2000-08-11 | 2002-02-21 | Ishihara Sangyo Kaisha, Ltd. | Colloidal metal solution, process for producing the same, and coating material containing the same |
| US7557149B2 (en) | 2000-08-11 | 2009-07-07 | Ishihara Sangyo Kaisha, Ltd. | Colloidal metal solution, process for producing the same, and coating material containing the same |
| US7897675B2 (en) | 2000-08-11 | 2011-03-01 | Ishihara Sangyo Kaisha, Ltd. | Colloidal metal solution, process for producing the same and paint using the same |
| US7902292B2 (en) | 2000-08-11 | 2011-03-08 | Ishihara Sangyo Kaisha, Ltd. | Colloidal metal solution, process for producing the same and paint using the same |
| WO2005099939A1 (en) * | 2004-04-14 | 2005-10-27 | Mitsui Mining & Smelting Co., Ltd. | Silver powder coated with silver compound and manufacturing method thereof |
| JP2006152327A (en) * | 2004-11-25 | 2006-06-15 | Dowa Mining Co Ltd | Silver powder and production method therefor |
| JP2007016258A (en) * | 2005-07-05 | 2007-01-25 | Mitsui Mining & Smelting Co Ltd | High crystal silver powder, and method for producing the high crystal silver powder |
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| US10807161B2 (en) | 2014-09-29 | 2020-10-20 | Dowa Electronics Materials Co., Ltd. | Silver powder, method for producing same, and hydrophilic conductive paste |
| CN106825544A (en) * | 2017-02-17 | 2017-06-13 | 江苏欧耐尔新型材料股份有限公司 | Improve the high-specific surface area silver powder and preparation method of electrode of solar battery electric conductivity |
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