JP5519938B2 - Method for producing copper powder for conductive paste - Google Patents
Method for producing copper powder for conductive paste Download PDFInfo
- Publication number
- JP5519938B2 JP5519938B2 JP2009004661A JP2009004661A JP5519938B2 JP 5519938 B2 JP5519938 B2 JP 5519938B2 JP 2009004661 A JP2009004661 A JP 2009004661A JP 2009004661 A JP2009004661 A JP 2009004661A JP 5519938 B2 JP5519938 B2 JP 5519938B2
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- Prior art keywords
- copper
- particles
- reaction
- reducing agent
- solution
- 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.)
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- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 title claims description 237
- 238000004519 manufacturing process Methods 0.000 title claims description 30
- 239000002245 particle Substances 0.000 claims description 246
- 238000006243 chemical reaction Methods 0.000 claims description 197
- 239000010949 copper Substances 0.000 claims description 174
- 229910052802 copper Inorganic materials 0.000 claims description 166
- 239000000243 solution Substances 0.000 claims description 134
- 239000003638 chemical reducing agent Substances 0.000 claims description 103
- JPVYNHNXODAKFH-UHFFFAOYSA-N Cu2+ Chemical compound [Cu+2] JPVYNHNXODAKFH-UHFFFAOYSA-N 0.000 claims description 97
- 229910001431 copper ion Inorganic materials 0.000 claims description 97
- 239000007864 aqueous solution Substances 0.000 claims description 59
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 59
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical group OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 claims description 38
- 230000002776 aggregation Effects 0.000 claims description 22
- 150000001875 compounds Chemical class 0.000 claims description 22
- 230000002829 reductive effect Effects 0.000 claims description 22
- 238000004220 aggregation Methods 0.000 claims description 20
- 239000002211 L-ascorbic acid Substances 0.000 claims description 17
- 235000000069 L-ascorbic acid Nutrition 0.000 claims description 17
- 229920002873 Polyethylenimine Polymers 0.000 claims description 17
- 229960005070 ascorbic acid Drugs 0.000 claims description 17
- 239000003112 inhibitor Substances 0.000 claims description 14
- 239000000203 mixture Substances 0.000 claims description 14
- CIWBSHSKHKDKBQ-DUZGATOHSA-N D-isoascorbic acid Chemical compound OC[C@@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-DUZGATOHSA-N 0.000 claims description 10
- 229910000365 copper sulfate Inorganic materials 0.000 claims description 10
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 claims description 10
- 229910052788 barium Inorganic materials 0.000 claims description 8
- 229910052782 aluminium Inorganic materials 0.000 claims description 7
- 229920000609 methyl cellulose Polymers 0.000 claims description 7
- 239000001923 methylcellulose Substances 0.000 claims description 7
- 229910052719 titanium Inorganic materials 0.000 claims description 7
- 239000003795 chemical substances by application Substances 0.000 claims description 6
- 229910052751 metal Inorganic materials 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 6
- 229920003169 water-soluble polymer Polymers 0.000 claims description 6
- 229910052710 silicon Inorganic materials 0.000 claims description 5
- 230000002744 anti-aggregatory effect Effects 0.000 claims description 4
- XTVVROIMIGLXTD-UHFFFAOYSA-N copper(II) nitrate Chemical compound [Cu+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XTVVROIMIGLXTD-UHFFFAOYSA-N 0.000 claims description 4
- 239000003130 blood coagulation factor inhibitor Substances 0.000 claims description 3
- 239000002244 precipitate Substances 0.000 claims description 3
- 239000000853 adhesive Substances 0.000 claims 1
- 230000001070 adhesive effect Effects 0.000 claims 1
- 239000004020 conductor Substances 0.000 claims 1
- 239000010419 fine particle Substances 0.000 description 70
- 238000000034 method Methods 0.000 description 63
- 238000006722 reduction reaction Methods 0.000 description 56
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 34
- 230000000052 comparative effect Effects 0.000 description 32
- 238000003756 stirring Methods 0.000 description 32
- 239000000126 substance Substances 0.000 description 29
- BERDEBHAJNAUOM-UHFFFAOYSA-N copper(I) oxide Inorganic materials [Cu]O[Cu] BERDEBHAJNAUOM-UHFFFAOYSA-N 0.000 description 25
- KRFJLUBVMFXRPN-UHFFFAOYSA-N cuprous oxide Chemical compound [O-2].[Cu+].[Cu+] KRFJLUBVMFXRPN-UHFFFAOYSA-N 0.000 description 25
- 229940112669 cuprous oxide Drugs 0.000 description 25
- 230000009467 reduction Effects 0.000 description 25
- 238000009826 distribution Methods 0.000 description 22
- 239000003985 ceramic capacitor Substances 0.000 description 20
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 16
- 150000002500 ions Chemical class 0.000 description 16
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 15
- 238000007792 addition Methods 0.000 description 15
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 description 12
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 12
- 230000000694 effects Effects 0.000 description 12
- 239000010936 titanium Substances 0.000 description 11
- JJLJMEJHUUYSSY-UHFFFAOYSA-L Copper hydroxide Chemical compound [OH-].[OH-].[Cu+2] JJLJMEJHUUYSSY-UHFFFAOYSA-L 0.000 description 10
- 239000005750 Copper hydroxide Substances 0.000 description 10
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 10
- 239000000919 ceramic Substances 0.000 description 10
- 229910001956 copper hydroxide Inorganic materials 0.000 description 10
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 10
- NWZSZGALRFJKBT-KNIFDHDWSA-N (2s)-2,6-diaminohexanoic acid;(2s)-2-hydroxybutanedioic acid Chemical compound OC(=O)[C@@H](O)CC(O)=O.NCCCC[C@H](N)C(O)=O NWZSZGALRFJKBT-KNIFDHDWSA-N 0.000 description 9
- 239000011362 coarse particle Substances 0.000 description 9
- 229960004643 cupric oxide Drugs 0.000 description 9
- IKDUDTNKRLTJSI-UHFFFAOYSA-N hydrazine monohydrate Substances O.NN IKDUDTNKRLTJSI-UHFFFAOYSA-N 0.000 description 9
- 239000012299 nitrogen atmosphere Substances 0.000 description 9
- 229910052763 palladium Inorganic materials 0.000 description 9
- OAKJQQAXSVQMHS-UHFFFAOYSA-N Hydrazine Chemical compound NN OAKJQQAXSVQMHS-UHFFFAOYSA-N 0.000 description 8
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 8
- 230000002411 adverse Effects 0.000 description 8
- JZCCFEFSEZPSOG-UHFFFAOYSA-L copper(II) sulfate pentahydrate Chemical compound O.O.O.O.O.[Cu+2].[O-]S([O-])(=O)=O JZCCFEFSEZPSOG-UHFFFAOYSA-L 0.000 description 8
- 229910052757 nitrogen Inorganic materials 0.000 description 8
- 229910052709 silver Inorganic materials 0.000 description 8
- 238000009833 condensation Methods 0.000 description 7
- 230000005494 condensation Effects 0.000 description 7
- 238000001514 detection method Methods 0.000 description 7
- 238000002156 mixing Methods 0.000 description 7
- GPNDARIEYHPYAY-UHFFFAOYSA-N palladium(ii) nitrate Chemical compound [Pd+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O GPNDARIEYHPYAY-UHFFFAOYSA-N 0.000 description 7
- 239000005751 Copper oxide Substances 0.000 description 6
- 230000002378 acidificating effect Effects 0.000 description 6
- 229910000431 copper oxide Inorganic materials 0.000 description 6
- 235000010981 methylcellulose Nutrition 0.000 description 6
- 239000000843 powder Substances 0.000 description 6
- 239000011164 primary particle Substances 0.000 description 6
- 239000007788 liquid Substances 0.000 description 5
- 150000002736 metal compounds Chemical class 0.000 description 5
- 229910052759 nickel Inorganic materials 0.000 description 5
- 239000002994 raw material Substances 0.000 description 5
- 229910001961 silver nitrate Inorganic materials 0.000 description 5
- DHMQDGOQFOQNFH-UHFFFAOYSA-N Glycine Chemical compound NCC(O)=O DHMQDGOQFOQNFH-UHFFFAOYSA-N 0.000 description 4
- 238000001035 drying Methods 0.000 description 4
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 4
- 238000001556 precipitation Methods 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 239000011163 secondary particle Substances 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 3
- 229920000084 Gum arabic Polymers 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 241000978776 Senegalia senegal Species 0.000 description 3
- 239000000205 acacia gum Substances 0.000 description 3
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- 239000001913 cellulose Substances 0.000 description 3
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 239000003989 dielectric material Substances 0.000 description 3
- 235000014113 dietary fatty acids Nutrition 0.000 description 3
- 239000000194 fatty acid Substances 0.000 description 3
- 229930195729 fatty acid Natural products 0.000 description 3
- 150000004665 fatty acids Chemical class 0.000 description 3
- 238000001914 filtration Methods 0.000 description 3
- -1 hydrates) Chemical compound 0.000 description 3
- 150000002429 hydrazines Chemical class 0.000 description 3
- 239000007769 metal material Substances 0.000 description 3
- ACVYVLVWPXVTIT-UHFFFAOYSA-N phosphinic acid Chemical compound O[PH2]=O ACVYVLVWPXVTIT-UHFFFAOYSA-N 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- 150000003464 sulfur compounds Chemical class 0.000 description 3
- 230000000007 visual effect Effects 0.000 description 3
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 2
- 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 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 2
- 108010010803 Gelatin Proteins 0.000 description 2
- 239000004471 Glycine Substances 0.000 description 2
- QIGBRXMKCJKVMJ-UHFFFAOYSA-N Hydroquinone Chemical compound OC1=CC=C(O)C=C1 QIGBRXMKCJKVMJ-UHFFFAOYSA-N 0.000 description 2
- 206010065042 Immune reconstitution inflammatory syndrome Diseases 0.000 description 2
- 229910002651 NO3 Inorganic materials 0.000 description 2
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 2
- 239000002202 Polyethylene glycol Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 238000005054 agglomeration Methods 0.000 description 2
- 230000032683 aging Effects 0.000 description 2
- 150000004703 alkoxides Chemical class 0.000 description 2
- 235000011114 ammonium hydroxide Nutrition 0.000 description 2
- JRPBQTZRNDNNOP-UHFFFAOYSA-N barium titanate Chemical compound [Ba+2].[Ba+2].[O-][Ti]([O-])([O-])[O-] JRPBQTZRNDNNOP-UHFFFAOYSA-N 0.000 description 2
- 229910002113 barium titanate Inorganic materials 0.000 description 2
- QRUDEWIWKLJBPS-UHFFFAOYSA-N benzotriazole Chemical compound C1=CC=C2N[N][N]C2=C1 QRUDEWIWKLJBPS-UHFFFAOYSA-N 0.000 description 2
- 239000012964 benzotriazole Substances 0.000 description 2
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 239000002738 chelating agent Substances 0.000 description 2
- 239000008139 complexing agent Substances 0.000 description 2
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- 239000004318 erythorbic acid Substances 0.000 description 2
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- 235000019322 gelatine Nutrition 0.000 description 2
- 235000011852 gelatine desserts Nutrition 0.000 description 2
- MNWFXJYAOYHMED-UHFFFAOYSA-N heptanoic acid Chemical compound CCCCCCC(O)=O MNWFXJYAOYHMED-UHFFFAOYSA-N 0.000 description 2
- 150000004677 hydrates Chemical class 0.000 description 2
- LELOWRISYMNNSU-UHFFFAOYSA-N hydrogen cyanide Chemical compound N#C LELOWRISYMNNSU-UHFFFAOYSA-N 0.000 description 2
- 229940026239 isoascorbic acid Drugs 0.000 description 2
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- LNAZSHAWQACDHT-XIYTZBAFSA-N (2r,3r,4s,5r,6s)-4,5-dimethoxy-2-(methoxymethyl)-3-[(2s,3r,4s,5r,6r)-3,4,5-trimethoxy-6-(methoxymethyl)oxan-2-yl]oxy-6-[(2r,3r,4s,5r,6r)-4,5,6-trimethoxy-2-(methoxymethyl)oxan-3-yl]oxyoxane Chemical compound CO[C@@H]1[C@@H](OC)[C@H](OC)[C@@H](COC)O[C@H]1O[C@H]1[C@H](OC)[C@@H](OC)[C@H](O[C@H]2[C@@H]([C@@H](OC)[C@H](OC)O[C@@H]2COC)OC)O[C@@H]1COC LNAZSHAWQACDHT-XIYTZBAFSA-N 0.000 description 1
- PYSRRFNXTXNWCD-UHFFFAOYSA-N 3-(2-phenylethenyl)furan-2,5-dione Chemical compound O=C1OC(=O)C(C=CC=2C=CC=CC=2)=C1 PYSRRFNXTXNWCD-UHFFFAOYSA-N 0.000 description 1
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- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- BQDSDRAVKYTTTH-UHFFFAOYSA-N barium(2+);methanolate Chemical compound [Ba+2].[O-]C.[O-]C BQDSDRAVKYTTTH-UHFFFAOYSA-N 0.000 description 1
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- DOBRDRYODQBAMW-UHFFFAOYSA-N copper(i) cyanide Chemical compound [Cu+].N#[C-] DOBRDRYODQBAMW-UHFFFAOYSA-N 0.000 description 1
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- KOUDKOMXLMXFKX-UHFFFAOYSA-N sodium oxido(oxo)phosphanium hydrate Chemical compound O.[Na+].[O-][PH+]=O KOUDKOMXLMXFKX-UHFFFAOYSA-N 0.000 description 1
- NNMHYFLPFNGQFZ-UHFFFAOYSA-M sodium polyacrylate Chemical compound [Na+].[O-]C(=O)C=C NNMHYFLPFNGQFZ-UHFFFAOYSA-M 0.000 description 1
- IVQVTRZCAXVNSG-UHFFFAOYSA-M sodium;prop-2-enoate;prop-2-enoic acid Chemical compound [Na+].OC(=O)C=C.[O-]C(=O)C=C IVQVTRZCAXVNSG-UHFFFAOYSA-M 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000012798 spherical particle Substances 0.000 description 1
- 239000008107 starch Substances 0.000 description 1
- 235000019698 starch Nutrition 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 239000012756 surface treatment agent Substances 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- VXUYXOFXAQZZMF-UHFFFAOYSA-N titanium(IV) isopropoxide Chemical compound CC(C)O[Ti](OC(C)C)(OC(C)C)OC(C)C VXUYXOFXAQZZMF-UHFFFAOYSA-N 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- AVBGNFCMKJOFIN-UHFFFAOYSA-N triethylammonium acetate Chemical compound CC(O)=O.CCN(CC)CC AVBGNFCMKJOFIN-UHFFFAOYSA-N 0.000 description 1
- 150000004684 trihydrates Chemical class 0.000 description 1
- 238000001132 ultrasonic dispersion Methods 0.000 description 1
- 238000001291 vacuum drying Methods 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/16—Making metallic powder or suspensions thereof using chemical processes
- B22F9/18—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds
- B22F9/24—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from liquid metal compounds, e.g. solutions
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
- B22F1/17—Metallic particles coated with metal
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
- H01B1/02—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of metals or alloys
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/16—Making metallic powder or suspensions thereof using chemical processes
- B22F9/18—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds
- B22F9/24—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from liquid metal compounds, e.g. solutions
- B22F2009/245—Reduction reaction in an Ionic Liquid [IL]
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F2301/00—Metallic composition of the powder or its coating
- B22F2301/10—Copper
Description
本発明は、導電性ペースト用銅粉およびその製造方法に関し、特に、積層セラミックコンデンサや積層セラミックインダクタなどの積層セラミック電子部品の内部電極や、小型積層セラミックコンデンサや積層セラミックインダクタなどの外部電極を形成するための導電性ペーストに使用する銅粉およびその製造方法に関する。 The present invention relates to copper powder for conductive paste and a method for manufacturing the same, and in particular, forms internal electrodes of multilayer ceramic electronic components such as multilayer ceramic capacitors and multilayer ceramic inductors, and external electrodes such as small multilayer ceramic capacitors and multilayer ceramic inductors. The present invention relates to a copper powder used in a conductive paste for manufacturing and a manufacturing method thereof.
積層セラミックコンデンサの一般的な製造方法では、まず、チタン酸バリウム系セラミックなどの誘電体セラミックグリーンシートを複数枚用意し、各々のシートの上に、内部電極用の導電性ペーストを所定のパターンで印刷し、これらのシートを積み重ねて圧着することによって、誘電体セラミックグリーンシートと導電性ペースト層が交互に積層された積層体を作製する。この積層体を所定の形状の複数のチップに切断した後、高温で同時に焼成して、積層セラミックコンデンサの素体を作製する。次いで、この素体の内部電極が露出する端面に、導電性粉体、ガラス粉末および有機ビヒクルを主成分とする外部電極用の導電性ペーストを塗布し、乾燥した後、高温で焼成することによって外部電極を形成する。その後、必要に応じて外部電極にニッケルやスズなどのめっき層を電気めっきなどにより形成する。 In a general manufacturing method of a multilayer ceramic capacitor, first, a plurality of dielectric ceramic green sheets such as barium titanate ceramics are prepared, and a conductive paste for internal electrodes is formed in a predetermined pattern on each sheet. By printing and stacking and pressing these sheets, a laminated body in which dielectric ceramic green sheets and conductive paste layers are alternately laminated is produced. The multilayer body is cut into a plurality of chips having a predetermined shape and then simultaneously fired at a high temperature to produce a multilayer ceramic capacitor element body. Next, a conductive paste for an external electrode mainly composed of conductive powder, glass powder and an organic vehicle is applied to the end face where the internal electrode of the element body is exposed, dried, and then fired at a high temperature. External electrodes are formed. Thereafter, if necessary, a plating layer of nickel, tin, or the like is formed on the external electrode by electroplating or the like.
従来、このような積層セラミックコンデンサなどの内部電極を形成するための導電性ペーストに使用する金属材料として、パラジウム、銀−パラジウム、白金などが使用されていたが、これらは高価な貴金属であるため、コストがかかるという問題があった。そのため、近年では、ニッケルや銅などの卑金属を使用するのが主流になってきており、現在では、主にニッケル微粒子（積層セラミックコンデンサの大きさや容量などにもよるが、一般に平均粒径０．１〜０．５μｍのニッケル微粒子）が使用されている。また、銅は、ニッケルと比べて、導電率が高く、融点が低いため、積層セラミックコンデンサの特性を改善し、焼成時の低温化などの生産時の省エネに寄与することが可能であり、今後の内部電極用の金属材料の有望な一つとして期待されている。 Conventionally, palladium, silver-palladium, platinum, and the like have been used as metal materials used in conductive pastes for forming internal electrodes such as multilayer ceramic capacitors, but these are expensive noble metals. There was a problem of cost. Therefore, in recent years, the use of base metals such as nickel and copper has become mainstream, and at present, nickel fine particles (although depending on the size and capacity of the multilayer ceramic capacitor, the average particle size is generally 0. 0). 1 to 0.5 μm nickel fine particles) are used. Also, copper has higher electrical conductivity and lower melting point than nickel, so it can improve the characteristics of multilayer ceramic capacitors and contribute to energy saving during production, such as lower temperatures during firing. It is expected as a promising metal material for internal electrodes.
一方、近年、積層セラミックコンデンサなどの高容量化や小型化のために、内部電極の薄層化が求められている。また、積層セラミックコンデンサなどの用途の拡大により、内部インダクタが小さく、高周波数特性としてＧＨｚオーダーまで使用可能な特性を有する積層セラミックコンデンサなどが求められている。 On the other hand, in recent years, there has been a demand for thinner internal electrodes in order to increase the capacity and size of multilayer ceramic capacitors and the like. In addition, with the expansion of applications such as multilayer ceramic capacitors, multilayer ceramic capacitors having small internal inductors and high frequency characteristics that can be used up to GHz order are required.
このような背景から、積層セラミックコンデンサなどの内部電極用の金属材料として、単分散した微粒子で、粒度分布がシャープで、粗粒を含まず、形状が真球に近いなどの特性を有する銅微粒子が求められている。 Against this background, as a metal material for internal electrodes such as multilayer ceramic capacitors, copper fine particles are monodispersed fine particles, have a sharp particle size distribution, do not contain coarse particles, and have a shape close to a true sphere. Is required.
現在、銅微粒子は、主に積層セラミックコンデンサなどの外部電極用の導電性ペーストに使用されており、銅微粒子の大きさは、積層セラミックコンデンサなどの大きさにもよるが、０．５〜１０μｍ程度であり、球状、フレーク状、不定形状などの様々な形状の銅微粒子が使用されている。また、一般的な外部電極用の導電性ペーストには、上記の大きさや形状の銅微粒子が混合されて使用されている。 At present, copper fine particles are mainly used in conductive pastes for external electrodes such as multilayer ceramic capacitors. The size of copper fine particles depends on the size of the multilayer ceramic capacitors, but is 0.5 to 10 μm. The copper fine particles having various shapes such as spherical shape, flake shape, and irregular shape are used. Also, general conductive paste for external electrodes is used by mixing copper fine particles of the above size and shape.
このような銅微粒子の製造方法として、硫酸銅溶液をＬ−アルコスビン酸またはＬ−アスコルビン酸塩類で還元する方法（例えば、特許文献１参照）、硫酸銅溶液をＤ−エリソルビン酸またはＤ−エリソルビン酸塩類で還元する方法（例えば、特許文献２参照）、硫酸銅溶液を水素化ホウ素化合物で還元する方法（例えば、特許文献３参照）、硫酸銅溶液をヒドロキシル（−ＯＨ）基を含む芳香族化合物で還元する方法（例えば、特許文献４参照）、銅イオン、還元剤および錯化剤からなる混合水溶液に反応開始剤を添加して還元反応させた後に、銅イオン、還元剤、ｐＨ調整剤を添加して銅微粉末を製造する方法（例えば、特許文献５参照）、２価の銅イオンを有する銅塩水溶液に水酸化アルカリを混合して酸化第二銅を生成し、還元糖を加えて酸化第二銅を酸化第一銅に還元し、さらにヒドラジン系還元剤を加えて酸化第一銅を還元する方法（例えば、特許文献６参照）、硫黄系化合物と保護コロイドを存在させた溶媒液中において、酸化銅をヒドラジンなどの還元剤と反応させて銅微粒子を製造する方法（例えば、特許文献７参照）などが提案されている。 As a method for producing such copper fine particles, a method of reducing a copper sulfate solution with L-arcosbic acid or L-ascorbate (see, for example, Patent Document 1), a copper sulfate solution with D-erythorbic acid or D-erythorbic acid A method of reducing with a salt (for example, see Patent Document 2), a method of reducing a copper sulfate solution with a borohydride compound (for example, see Patent Document 3), and an aromatic compound containing a hydroxyl (—OH) group in the copper sulfate solution. After reducing the reaction by adding a reaction initiator to a mixed aqueous solution composed of copper ions, a reducing agent and a complexing agent (for example, see Patent Document 4), the copper ions, the reducing agent and the pH adjuster are added. A method for producing a copper fine powder by adding (see, for example, Patent Document 5) A cupric oxide is produced by mixing an alkali hydroxide with a copper salt aqueous solution having divalent copper ions, and reducing sugar is added. A method of reducing cuprous oxide to cuprous oxide and reducing cuprous oxide by adding a hydrazine-based reducing agent (for example, see Patent Document 6), a solvent in which a sulfur-based compound and a protective colloid are present A method of producing copper fine particles by reacting copper oxide with a reducing agent such as hydrazine in a liquid (for example, see Patent Document 7) has been proposed.
しかし、特許文献１の方法で得られる銅微粒子の平均粒径は、１．０〜１．８μｍであり、内部電極用の銅微粒子として使用するには十分ではない。また、ｐＨを調整した銅イオンの水溶液とｐＨを調整した還元剤の水溶液を用いて、銅イオンから亜酸化銅を経て銅粒子に還元させるため、粒径の制御が不安定であり、凝結（粒子同士の結合）が生じ、形状が一定にならず、粒度分布がブロードになる場合がある。 However, the average particle diameter of copper fine particles obtained by the method of Patent Document 1 is 1.0 to 1.8 μm, which is not sufficient for use as copper fine particles for internal electrodes. In addition, using an aqueous solution of copper ions adjusted in pH and an aqueous solution of a reducing agent adjusted in pH, copper particles are reduced to copper particles through cuprous oxide, so the control of the particle size is unstable and condensation ( (Bonding between particles) occurs, the shape is not constant, and the particle size distribution may be broad.
また、特許文献２の方法で得られる銅微粒子の平均粒径は、０．８〜２．０μｍであり、内部電極用の銅微粒子として使用するには十分ではない。また、ｐＨ調整した銅イオンの水溶液とｐＨ調整した還元剤の水溶液を用いて、銅イオンから亜酸化銅を経て銅粒子に還元させるため、粒径の制御が不安定であり、凝結（粒子同士の結合）が生じ、形状が一定にならず、粒度分布がブロードになる場合がある。 Moreover, the average particle diameter of the copper fine particles obtained by the method of Patent Document 2 is 0.8 to 2.0 μm, which is not sufficient for use as copper fine particles for internal electrodes. In addition, since the pH-adjusted aqueous solution of copper ions and the aqueous solution of reducing agent adjusted in pH are used to reduce copper ions to copper particles through cuprous oxide, the control of the particle size is unstable, and condensation (particles May occur, the shape may not be constant, and the particle size distribution may be broad.
また、特許文献３の方法で得られる銅微粒子の平均粒径は、０．３〜０．７μｍであり、特許文献１および２の方法で得られる銅微粒子と比べれば小さい銅微粒子を得ることができるが、この場合も内部電極用の銅微粒子として使用するには、まだ十分ではない。また、還元剤として水素化ホウ素化合物を使用するため、還元剤のｐＨ調整時にｐＨが低いと、自己分解が起こり、作業性や安定性が悪くなる場合がある。一方、ｐＨを高くすれば水素化ホウ素化合物は安定するが、その場合、銅イオンの還元反応が亜酸化銅を経て行われるので、粒径の制御が不安定であり、凝結（粒子同士の結合）が生じ、形状が一定にならず、粒度分布がブロードになる場合がある。 Moreover, the average particle diameter of the copper fine particles obtained by the method of Patent Document 3 is 0.3 to 0.7 μm, and it is possible to obtain small copper fine particles as compared with the copper fine particles obtained by the methods of Patent Documents 1 and 2. Although this is possible, it is still not sufficient for use as copper fine particles for internal electrodes. In addition, since a borohydride compound is used as the reducing agent, if the pH is low when adjusting the pH of the reducing agent, self-decomposition occurs, and workability and stability may deteriorate. On the other hand, if the pH is increased, the borohydride compound becomes stable. In this case, since the reduction reaction of copper ions is performed through cuprous oxide, the control of the particle size is unstable, and condensation (bonding between particles) occurs. ) May occur, the shape may not be constant, and the particle size distribution may be broad.
また、特許文献４の方法で得られる銅微粒子の平均粒径は、０．７〜１．５μｍであり、内部電極用の銅微粒子として使用するには十分ではない。また、還元剤としてヒドロキノンを使用しており、反応ｐＨや反応温度などを調整しても、銅粒子をさらに微粒子化するのは困難である。また、ｐＨ調整した銅イオンの水溶液とｐＨ調整した還元剤の水溶液を用いて、銅イオンから亜酸化銅を経て銅粒子に還元させるため、粒径の制御が不安定であり、凝結（粒子同士の結合）が生じ、形状が一定にならず、粒度分布がブロードになる場合がある。 Moreover, the average particle diameter of the copper fine particles obtained by the method of Patent Document 4 is 0.7 to 1.5 μm, which is not sufficient for use as copper fine particles for internal electrodes. Further, hydroquinone is used as a reducing agent, and even if the reaction pH, reaction temperature, etc. are adjusted, it is difficult to further reduce the copper particles. In addition, since the pH-adjusted aqueous solution of copper ions and the aqueous solution of reducing agent adjusted in pH are used to reduce copper ions to copper particles through cuprous oxide, the control of the particle size is unstable, and condensation (particles May occur, the shape may not be constant, and the particle size distribution may be broad.
また、特許文献５の方法で得られる銅微粒子の平均粒径は、０．１６〜０．６１μｍであり、平均粒径から判断すれば、内部電極用の銅粉として使用することができると考えられる。しかし、この方法では、還元反応を高ｐＨ領域（ｐＨ１２〜１３．５）で行っているので、銅イオンから水酸化銅、酸化銅、亜酸化銅を経て銅粒子に還元させるため、粒径の制御が不安定であり、凝結（粒子同士の結合）が生じ、形状が一定にならず、粒度分布がブロードになる場合がある。 Moreover, the average particle diameter of the copper fine particles obtained by the method of Patent Document 5 is 0.16 to 0.61 μm, and it can be used as copper powder for internal electrodes if judged from the average particle diameter. It is done. However, in this method, since the reduction reaction is performed in a high pH region (pH 12 to 13.5), in order to reduce copper ions to copper particles via copper hydroxide, copper oxide, and cuprous oxide, The control is unstable, condensation (bonding between particles) occurs, the shape is not constant, and the particle size distribution may be broad.
また、特許文献６の方法で得られる銅微粒子の平均粒径は、０．５〜４．０μｍであり、内部電極用の銅微粒子として使用するには十分ではない。また、この方法の反応は、２価の銅イオンから生成した酸化第二銅を酸化第一銅に還元した後にさらに銅粒子に還元する反応であり、酸化第二銅から銅粒子への還元反応は、溶解析出型といわれる反応である。この方法をある程度粒径が大きい銅粒子の製造に用いる場合には、安定した制御を行うことができ、粒度分布をシャープすることができるが、内部電極用の銅微粒子として用いられるような微細な銅微粒子を得るのが困難であり、（連晶粒子や凝結粒子を含まない）個々に分離した微細粒子を得るのが困難である。 Moreover, the average particle diameter of the copper fine particles obtained by the method of Patent Document 6 is 0.5 to 4.0 μm, which is not sufficient for use as copper fine particles for internal electrodes. The reaction of this method is a reaction in which cupric oxide generated from divalent copper ions is reduced to cuprous oxide and then further reduced to copper particles. Reduction reaction from cupric oxide to copper particles Is a reaction called dissolution precipitation type. When this method is used for the production of copper particles having a large particle size, stable control can be performed and the particle size distribution can be sharpened, but the fine particles used as copper fine particles for internal electrodes can be used. It is difficult to obtain copper fine particles, and it is difficult to obtain finely separated fine particles (not including intergrowth particles and condensed particles).
さらに、特許文献７の方法で得られる銅微粒子の平均粒径は、一次粒子径が０．２５〜０．５μｍ、二次粒子径が０．３〜０．６μｍであり、平均粒径から判断すれば、内部電極用の銅粉として使用することができると考えられる。また、タップ密度が３．２〜３．４ｇ／ｃｍ３と微粒子にしては高タップ密度であり、分散性に優れているといえる。しかし、特許文献７の方法の反応は、硫黄化合物の存在下における反応であるため、銅微粒子の内部や表面に硫黄化合物が含まれる可能性がある。一般に、硫黄は電子部品の信頼性に悪影響を与える物質であるため、導電性ペースト用銅粉に含まれるのは好ましくない。 Furthermore, the average particle diameter of the copper fine particles obtained by the method of Patent Document 7 is 0.25 to 0.5 μm for the primary particle diameter and 0.3 to 0.6 μm for the secondary particle diameter, and is determined from the average particle diameter. If so, it can be used as copper powder for internal electrodes. In addition, it can be said that the tap density is 3.2 to 3.4 g / cm 3 and the fine particles have a high tap density and are excellent in dispersibility. However, since the reaction of the method of Patent Document 7 is a reaction in the presence of a sulfur compound, there is a possibility that the sulfur compound is contained inside or on the surface of the copper fine particles. In general, since sulfur is a substance that adversely affects the reliability of electronic components, it is not preferable to contain it in copper powder for conductive paste.
したがって、本発明は、このような従来の問題点に鑑み、単分散した微粒子で、粒度分布がシャープで、粗粒を含まず、形状が真球に近いなどの特性を有する銅微粒子であり、電気的特性への悪影響を回避しながら、電極の薄膜化を可能にする導電性ペースト用銅粉およびそのような導電性ペースト用銅粉を安定して製造することができる方法を提供することを目的とする。 Therefore, in view of such conventional problems, the present invention is a monodispersed fine particle, the particle size distribution is sharp, does not include coarse particles, and the copper fine particles have characteristics such as a shape close to a true sphere, To provide a copper powder for conductive paste that enables thinning of an electrode and a method capable of stably producing such copper powder for conductive paste while avoiding adverse effects on electrical characteristics Objective.
本発明者らは、上記課題を解決するために鋭意研究した結果、２価の銅イオンを含む水溶液に還元剤を添加して銅粒子を還元析出させる銅粉の製造方法において、２価の銅イオンを含む水溶液および還元剤の少なくとも一方に、凝集防止剤を含む反応促進剤を存在させることにより、単分散した微粒子で、粒度分布がシャープで、粗粒を含まず、形状が真球に近いなどの特性を有する銅微粒子であり、電気的特性への悪影響を回避しながら、電極の薄膜化を可能にする導電性ペースト用銅粉を安定して製造することができることを見出し、本発明を完成するに至った。 As a result of diligent research to solve the above-mentioned problems, the present inventors have added a reducing agent to an aqueous solution containing divalent copper ions, and in the method for producing copper powder in which copper particles are reduced and precipitated, divalent copper. The presence of a reaction accelerator containing an agglomeration inhibitor in at least one of an aqueous solution containing ions and a reducing agent allows monodispersed fine particles, sharp particle size distribution, no coarse particles, and a shape close to a true sphere. It has been found that the copper fine particles for conductive paste that can reduce the thickness of the electrode can be stably produced while avoiding adverse effects on the electrical characteristics, and the copper fine particles having characteristics such as It came to be completed.
すなわち、本発明による導電性ペースト用銅粉の製造方法は、２価の銅イオンを含む水溶液に還元剤を添加して銅粒子を還元析出させる銅粉の製造方法において、２価の銅イオンを含む水溶液および還元剤の少なくとも一方に、凝集防止剤を含む反応促進剤を存在させることを特徴とする。この導電性ペースト用銅粉の製造方法において、反応促進剤が銅より貴な金属の粒子からなるのが好ましく、平均粒子径１０〜１００ｎｍのＡｇ粒子およびＰｄ粒子の少なくとも一方からなるのがさらに好ましい。また、凝集防止剤が水溶性ポリマーであるのが好ましく、ポリエチレンイミンまたはメチルセルロースであるのがさらに好ましい。また、還元剤が、Ｌ−アスコルビン酸、Ｄ−エリソルビン酸またはこれらの混合物であるのが好ましい。さらに、２価の銅イオンを含む水溶液が、硫酸銅、硝酸銅またはこれらの混合物の水溶液であるのが好ましい。また、還元析出した銅粒子の表面にＡｌ、Ｂａ、ＴｉおよびＳｉからなる群から選ばれる一種以上を含む化合物を被着させてもよく、還元析出した銅粒子の表面をＡｌ、Ｂａ、ＴｉおよびＳｉからなる群から選ばれる一種以上を含む化合物で被覆してもよい。 That is, the method for producing a copper powder for conductive paste according to the present invention is a method for producing a copper powder in which a reducing agent is added to an aqueous solution containing divalent copper ions to reduce and precipitate copper particles. A reaction accelerator containing an aggregation inhibitor is present in at least one of the aqueous solution and the reducing agent. In this method for producing a copper powder for conductive paste, the reaction accelerator is preferably composed of particles of metal nobler than copper, and more preferably composed of at least one of Ag particles and Pd particles having an average particle diameter of 10 to 100 nm. . Further, the aggregation inhibitor is preferably a water-soluble polymer, more preferably polyethyleneimine or methylcellulose. Further, the reducing agent is preferably L-ascorbic acid, D-erythorbic acid or a mixture thereof. Furthermore, the aqueous solution containing divalent copper ions is preferably an aqueous solution of copper sulfate, copper nitrate or a mixture thereof. Further, a compound containing one or more selected from the group consisting of Al, Ba, Ti and Si may be deposited on the surface of the reduced and precipitated copper particles, and the surface of the reduced and precipitated copper particles may be coated with Al, Ba, Ti and You may coat | cover with the compound containing 1 or more types chosen from the group which consists of Si.
また、本発明による導電性ペースト用銅粉は、レーザー回折式粒度分布測定装置によって測定された５０％粒径（Ｄ５０）が０．１〜０．５μｍ、検出の最大粒径（Ｄｍａｘ）が１．５μｍ以下であり、１０〜１００００ｐｐｍのＡｇおよびＰｄの少なくとも一方を含むことを特徴とする。この導電性ペースト用銅粉において、ＳＥＭによって観測された銅単体粒子の平均粒径（単体粒子径）に対する、レーザー回折式粒度分布測定装置によって観測された凝集粒子の５０％粒径（凝集粒子径）の比（二次粒子径／一次粒子径）が２．０以下であるのが好ましい。また、ＳＥＭによって観測された銅粒子の中で単一の略球状の銅粒子の個数の割合が９０％以上であるのが好ましい。さらに、導電性ペースト用銅粉の表面にＡｌ、Ｂａ、ＴｉおよびＳｉからなる群から選ばれる一種以上を含む化合物を被着させてもよく、導電性ペースト用銅粉の表面をＡｌ、Ｂａ、ＴｉおよびＳｉからなる群から選ばれる一種以上を含む化合物で被覆してもよい。 The copper powder for conductive paste according to the present invention has a 50% particle size (D 50 ) measured by a laser diffraction particle size distribution measuring device of 0.1 to 0.5 μm, and a maximum particle size (D max ) for detection. Is 1.5 μm or less, and contains at least one of 10 to 10000 ppm of Ag and Pd. In this copper powder for conductive paste, the 50% particle diameter (aggregated particle diameter) of the aggregated particles observed by the laser diffraction particle size distribution measuring device with respect to the average particle diameter (single particle diameter) of the copper single particle observed by SEM ) Ratio (secondary particle diameter / primary particle diameter) is preferably 2.0 or less. Moreover, it is preferable that the ratio of the number of single substantially spherical copper particles among the copper particles observed by SEM is 90% or more. Furthermore, the surface of the copper powder for conductive paste may be coated with a compound containing one or more selected from the group consisting of Al, Ba, Ti and Si, and the surface of the copper powder for conductive paste may be coated with Al, Ba, You may coat | cover with the compound containing 1 or more types chosen from the group which consists of Ti and Si.
さらに、本発明による導電性ペーストは、導電性粉体として上記の導電性ペースト用銅粉を含むことを特徴とする。 Furthermore, the conductive paste according to the present invention is characterized by containing the above-described copper powder for conductive paste as a conductive powder.
本発明によれば、単分散した微粒子で、粒度分布がシャープで、粗粒を含まず、形状が真球に近いなどの特性を有する銅微粒子であり、電気的特性への悪影響を回避しながら、電極の薄膜化を可能にする導電性ペースト用銅粉を安定して製造することができる。 According to the present invention, monodispersed fine particles are copper fine particles having characteristics such as a sharp particle size distribution, no coarse particles, and a shape close to a true sphere, while avoiding adverse effects on electrical characteristics. The copper powder for conductive paste that enables the electrode to be thin can be stably produced.
本発明による導電性ペースト用銅粉の製造方法の実施の形態では、２価の銅イオンを含む水溶液に還元剤を添加して銅粒子を還元析出させる銅粉の製造方法において、２価の銅イオンを含む水溶液および還元剤の少なくとも一方に、凝集防止剤を含む反応促進剤（核剤）を存在させる。 In embodiment of the manufacturing method of the copper powder for electrically conductive paste by this invention, in the manufacturing method of the copper powder which adds a reducing agent to the aqueous solution containing a bivalent copper ion, and carries out reduction | restoration precipitation of a copper particle, bivalent copper A reaction accelerator (nucleating agent) containing an aggregation inhibitor is present in at least one of the aqueous solution containing ions and the reducing agent.
本発明による導電性ペースト用銅粉の製造方法の実施の形態は、２価の銅イオンを含む水溶液を、水酸化銅、酸化銅、亜酸化銅またはこれらの混合物を経由することなく、銅粒子まで直接還元する方法である。このような反応プロセスを取ることにより、粒径および粒度分布を制御するために存在する反応促進剤が効果的に作用する。また、水酸化銅、酸化銅または亜酸化銅の中間体を経由する溶解析出型の還元反応にならないので、粒子同士の凝集、凝結および結合が抑制された高分散した銅微粒子を得ることができる。すなわち、２価の銅イオンが、反応促進剤の表面で還元されて銅微粒子になる。 Embodiment of the manufacturing method of the copper powder for electrically conductive pastes by this invention is copper particle | grains, without passing aqueous solution containing a bivalent copper ion through copper hydroxide, copper oxide, cuprous oxide, or a mixture thereof. It is a method of reducing directly. By taking such a reaction process, the reaction accelerator which exists in order to control a particle size and a particle size distribution acts effectively. In addition, since it does not result in a dissolution-precipitation type reduction reaction via an intermediate of copper hydroxide, copper oxide or cuprous oxide, highly dispersed copper fine particles in which aggregation, aggregation and bonding between particles are suppressed can be obtained. . That is, divalent copper ions are reduced on the surface of the reaction accelerator to become copper fine particles.
湿式反応によって銅粉を製造する従来の一般的な方法では、２価の銅イオンを中和して、水酸化銅を作製し、温度調整により脱水反応を促進させて酸化銅を作製している。また、酸化銅を糖類などの弱い還元剤で亜酸化銅まで一次還元して生成した亜酸化銅を、ヒドラジンなどの強力な還元剤で銅粒子まで二次還元する方法も知られている。この方法の二次還元反応（亜酸化銅から銅への還元）では、亜酸化銅の固体から銅イオンが析出した後、その一部が還元されて銅の微細な核が生成され、その核が成長して銅粒子になる。この場合、銅イオンが亜酸化銅から溶解する反応と、溶解した銅イオンが銅粒子に還元される反応との２種類の反応が行われる。そのため、銅の微細な核を生成する工程と、その核が成長する工程とを厳密に分離し難く、その結果、二次核が発生し、粒度分布がブロードになり、粒径を制御し難い反応になる。また、還元初期の銅イオンの供給量が少ないので（大部分の銅は反応溶液中ではなく亜酸化銅中にあるので）、多量の核を発生させ難く、微粒子を得るのが困難である。また、還元剤の添加量を多くしたり、反応温度を高くしたりすることによって、多量の核を発生させるために銅イオンの溶解量を多くすることができたとしても、同時に還元反応を促進させることにもなり、その結果、還元と溶解が同時に起こることによって、異形粒子（粒子同士が凝結または結合して歪んだ形になった粒子）が多く発生するなどの問題がある。加えて、急激な反応になるため、液噴きや突沸が起こり、反応の安全面や再現性の面からも好ましくない。 In the conventional general method for producing copper powder by wet reaction, divalent copper ions are neutralized to produce copper hydroxide, and the dehydration reaction is promoted by adjusting the temperature to produce copper oxide. . There is also known a method in which cuprous oxide produced by primary reduction of cuprous oxide to cuprous oxide with a weak reducing agent such as saccharide is secondarily reduced to copper particles with a strong reducing agent such as hydrazine. In the secondary reduction reaction (reduction from cuprous oxide to copper) of this method, after copper ions are precipitated from the cuprous oxide solid, a part of it is reduced to produce fine copper nuclei. Grow into copper particles. In this case, two types of reactions are performed: a reaction in which copper ions are dissolved from cuprous oxide and a reaction in which the dissolved copper ions are reduced to copper particles. Therefore, it is difficult to strictly separate the process of generating fine copper nuclei and the process of growing the nuclei. As a result, secondary nuclei are generated, the particle size distribution becomes broad, and the particle size is difficult to control. Become a reaction. In addition, since the supply amount of copper ions at the initial stage of reduction is small (most of the copper is not in the reaction solution but in cuprous oxide), it is difficult to generate a large amount of nuclei and it is difficult to obtain fine particles. Even if the amount of copper ions dissolved can be increased by increasing the amount of reducing agent added or increasing the reaction temperature to generate a large amount of nuclei, the reduction reaction is simultaneously promoted. As a result, there is a problem in that a large number of irregularly shaped particles (particles that are distorted due to condensation or bonding of particles) are generated by simultaneous reduction and dissolution. In addition, since the reaction becomes abrupt, liquid jetting or bumping occurs, which is not preferable from the viewpoint of safety and reproducibility of the reaction.
そのため、本発明による導電性ペースト用銅粉の製造方法の実施の形態では、反応促進剤が存在する反応系において、２価の銅イオンから、水酸化銅、酸化銅、亜酸化銅またはこれらの混合物を経由することなく、銅粒子まで直接還元させている。 Therefore, in the embodiment of the method for producing a copper powder for conductive paste according to the present invention, in a reaction system in which a reaction accelerator is present, from divalent copper ions, copper hydroxide, copper oxide, cuprous oxide or these The copper particles are directly reduced without going through the mixture.
２価の銅イオンを使用するのは、１価の銅イオンの場合には、水溶性反応系で簡便に取り扱うことができる原料がないためである。例えば、シアン化銅（Ｉ）の場合には、（アルカリ溶液では銅への還元反応時に水酸化銅または亜酸化銅を経由し、）酸性溶液中では有毒なシアン化水素が発生するので、安全に反応するためには相応の設備が必要であり、取扱上の制約も多くなる。２価の銅イオンの供給源になる原料として、コスト、入手し易さ、取り扱いの安全性から、硫酸銅（水和物を含む）、硝酸銅（水和物を含む）またはこれらの混合物を使用するのが好ましい。 The reason why divalent copper ions are used is that, in the case of monovalent copper ions, there are no raw materials that can be easily handled in a water-soluble reaction system. For example, in the case of copper (I) cyanide, toxic hydrogen cyanide is generated in an acidic solution (via an alkali solution via copper hydroxide or cuprous oxide during the reduction reaction to copper). In order to do so, appropriate equipment is required, and there are many restrictions on handling. As raw materials to be a source of divalent copper ions, copper sulfate (including hydrates), copper nitrate (including hydrates), or a mixture thereof is used because of cost, availability, and safety of handling. It is preferred to use.
２価の銅イオンを銅微粒子へ還元する還元剤として、Ｌ−アスコルビン酸、Ｄ−エリソルビン酸またはこれらの混合物を使用するのが好ましい。また、還元剤は、酸性側で２価の銅イオンを銅まで還元するのが好ましい。酸性側が好ましいのは、銅のｐＨ−電位図によれば、中性〜アルカリ性側での還元反応する場合は、２価の銅イオンの中和反応によって水酸化銅が生成するおそれがあり、また、水酸化銅が生成しなくても、亜酸化銅が生成するおそれがあるからである。また、使用する錯化剤やキレート剤などによって２価の銅イオンの各ｐＨにおける還元電位が変化するので、ｐＨを厳密に決定することはできないが、ｐＨ５以下、好ましくはｐＨ４以下で２価の銅イオンを銅まで還元する還元剤を使用するのが好ましい。なお、反応ｐＨは、低い程よいわけではない。反応ｐＨが低いと、２価の銅イオンの溶解度が高くなり、還元を阻害するおそれがあり、生成した銅粒子の再溶出が起こるため、反応ｐＨは１〜４であるのが好ましい。 It is preferable to use L-ascorbic acid, D-erythorbic acid or a mixture thereof as a reducing agent that reduces divalent copper ions to copper fine particles. Further, the reducing agent preferably reduces divalent copper ions to copper on the acidic side. According to the pH-potential diagram of copper, the acidic side is preferable. When a reduction reaction is carried out on the neutral to alkaline side, copper hydroxide may be generated by a neutralization reaction of divalent copper ions. This is because even if copper hydroxide is not generated, cuprous oxide may be generated. In addition, since the reduction potential of divalent copper ions at each pH varies depending on the complexing agent or chelating agent used, the pH cannot be determined strictly, but the divalent is not more than pH 5, preferably not more than pH 4. It is preferable to use a reducing agent that reduces copper ions to copper. Note that the lower the reaction pH, the better. When the reaction pH is low, the solubility of divalent copper ions increases, and there is a possibility that the reduction may be inhibited, and the produced copper particles are re-eluted. Therefore, the reaction pH is preferably 1 to 4.
このような還元剤として、Ｌ−アスコルビン酸、Ｄ−エリソルビン酸、次亜リン酸、次亜リン酸Ｎａ、水素化ホウ素化合物、ヒドラジン類などが挙げられる。しかし、本発明者らが鋭意研究した結果、ヒドラジン類は、酸性側でも２価の銅イオンを還元することができるが、酸性側では還元力が弱く、所望の粒径の銅粒子を得ることができなかった。また、次亜リン酸や次亜リン酸Ｎａでは、異形粒子（粒子同士が凝結または結合して歪んだ形になった粒子）が生じ、所望の形状および粒径の銅粒子を得ることができなかった。さらに、水素化ホウ素化合物は、酸性側では自己分解（水の還元）が生じて取り扱いが困難であった。一方、Ｌ−アスコルビン酸やＤ−エリソルビン酸は、酸性側で２価の銅イオンを銅まで還元することができ、取り扱い易く、所望の銅微粒子を得ることができるので、Ｌ−アスコルビン酸、Ｄ−エリソルビン酸またはこれらの混合物を使用するのが好ましい。 Examples of such a reducing agent include L-ascorbic acid, D-erythorbic acid, hypophosphorous acid, sodium hypophosphite, borohydride compounds, hydrazines, and the like. However, as a result of intensive studies by the present inventors, hydrazines can reduce divalent copper ions even on the acidic side, but the reducing power is weak on the acidic side, and copper particles having a desired particle size can be obtained. I could not. In addition, hypophosphorous acid or sodium hypophosphite produces irregularly shaped particles (particles that are distorted due to condensation or bonding between the particles), and copper particles having a desired shape and particle size can be obtained. There wasn't. Furthermore, the borohydride compound is difficult to handle due to autolysis (reduction of water) on the acidic side. On the other hand, L-ascorbic acid and D-erythorbic acid can reduce divalent copper ions to copper on the acidic side, are easy to handle, and can obtain desired copper fine particles. -It is preferred to use erythorbic acid or mixtures thereof.
反応促進剤として、ＴＥＭより観察された平均粒径が１０〜１００ｎｍのＡｇ粒子およびＰｄ粒子の少なくとも一方を使用するのが好ましい。ＡｇやＰｄの他に、Ａｕ、Ｐｔ、白金族元素なども使用することができるが、Ａｇ粒子やＰｄ粒子が好ましいのは、（平均粒径が１０〜１００ｎｍの）微粒な反応促進剤（核剤）を得るために、還元速度が速く（貴な金属である必要があり）、その結果、少量の使用で済むので、コストがそれ程かからず、また、一般に人体および環境への影響（Ｈｇなど）が懸念されない物質であるからである。 As the reaction accelerator, it is preferable to use at least one of Ag particles and Pd particles having an average particle diameter of 10 to 100 nm observed by TEM. In addition to Ag and Pd, Au, Pt, platinum group elements and the like can also be used. However, Ag particles and Pd particles are preferable because of a fine reaction accelerator (nucleus having an average particle diameter of 10 to 100 nm) (Required to be a noble metal), resulting in less cost and less cost, and generally less impact on the human body and the environment (Hg This is because the substance is not a concern.
得られる銅微粒子の粒子径は、反応促進剤として使用するＡｇ粒子やＰｄ粒子が、仕込みの銅イオンに対して何個存在するかによって決定される。反応促進剤の粒子径が１００ｎｍより大きい場合は、使用するＡｇやＰｄの割合が多くなり、コスト上不利になる。また、目的とする銅微粒子の粒径が０．１μｍである場合は、それより小さいＡｇ粒子およびＰｄ粒子の少なくとも一方を反応促進剤として使用するのが好ましい。コストおよび制御上の関係から（より多くの反応促進剤を添加すると仕込みの２価の銅イオン量および還元剤量が制約されるため）、目的とする銅粒子径に対して１／５０〜１／５の大きさの反応促進剤としてのＡｇ粒子およびＰｄ粒子の少なくとも一方を使用するのが好ましい。したがって、反応促進剤として、ＴＥＭより観察された平均粒径が１０〜１００ｎｍのＡｇ粒子およびＰｄ粒子の少なくとも一方を使用するのが好ましい。 The particle diameter of the obtained copper fine particles is determined by the number of Ag particles and Pd particles used as reaction accelerators with respect to the charged copper ions. When the particle size of the reaction accelerator is larger than 100 nm, the ratio of Ag or Pd to be used increases, which is disadvantageous in terms of cost. In addition, when the target copper fine particle has a particle size of 0.1 μm, it is preferable to use at least one of smaller Ag particles and Pd particles as a reaction accelerator. From a cost and control relationship (because addition of more reaction accelerators limits the amount of charged divalent copper ions and the amount of reducing agent), 1/50 to 1 to the target copper particle diameter It is preferable to use at least one of Ag particles and Pd particles as a reaction accelerator having a size of / 5. Therefore, it is preferable to use at least one of Ag particles and Pd particles having an average particle diameter of 10 to 100 nm observed by TEM as a reaction accelerator.
反応促進剤中に含まれる凝集防止剤は、銅粒子の凝集を防ぐためではなく、反応促進剤として生成したＡｇ粒子やＰｄ粒子の凝集を防ぐための凝集防止剤であり、その表面に銅が還元析出するのを阻害しないものであればよく、水溶性ポリマーを使用することができる。水溶性ポリマーの量は、生成する粒子径などにもよるが、Ａｇ粒子やＰｄ粒子の重量に対して１〜１０倍程度であるのが好ましい。 The aggregation inhibitor contained in the reaction accelerator is an aggregation inhibitor for preventing aggregation of Ag particles and Pd particles generated as a reaction accelerator, not to prevent aggregation of copper particles, and copper is present on the surface thereof. Any water-soluble polymer may be used as long as it does not inhibit the reduction precipitation. The amount of the water-soluble polymer is preferably about 1 to 10 times the weight of the Ag particles or Pd particles, although it depends on the particle size to be produced.
水溶性ポリマーとして、セルロース誘導体、ゼラチン、可溶性デンプン、デキストリン、アラビアゴム、キチン、キトサン、ポリビニルアルコール、ポリビニルピロリドン、ポリエチレングリコール、ポリエチレンイミン、ポリアクリルアミド、アクリル酸（塩）含有ポリマー、スチレン−無水マレイン酸共重合体の水酸化ナトリウム（部分）中和物、水溶性ポリウレタンなどを使用することができる。セルロース誘導体としては、メチルセルロース、エチルセルロース、ヒドロキシエチルセルロース、エチルヒドロキシエチルセルロース、カルボキシメチルセルロース、ヒドロキシプロピルセルロースおよびこれらのケン化物や、カチオン化セルロースなどがある。アクリル酸（塩）含有ポリマーとしては、ポリアクリル酸ナトリウム、ポリアクリル酸カリウム、ポリアクリル酸アンモニウム、ポリアクリル酸の水酸化ナトリウム部分中和物、アクリル酸ナトリウム−アクリル酸エステル共重合体などがある。水溶性ポリウレタンとしては、ポリエチレングリコールなどや、ポリイソシアネートの反応生成物などがある。これらの水溶性ポリマーのうち、ポリエチレンイミンまたはメチルセルロースを使用するのが好ましい。 As water-soluble polymers, cellulose derivatives, gelatin, soluble starch, dextrin, gum arabic, chitin, chitosan, polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene glycol, polyethyleneimine, polyacrylamide, acrylic acid (salt) -containing polymers, styrene-maleic anhydride A sodium hydroxide (partial) neutralized product of a copolymer, water-soluble polyurethane, or the like can be used. Examples of the cellulose derivative include methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, saponified products thereof, and cationized cellulose. Examples of the acrylic acid (salt) -containing polymer include sodium polyacrylate, potassium polyacrylate, ammonium polyacrylate, sodium hydroxide partial neutralized product of polyacrylic acid, and sodium acrylate-acrylic acid ester copolymer. . Examples of the water-soluble polyurethane include polyethylene glycol and a reaction product of polyisocyanate. Of these water-soluble polymers, polyethyleneimine or methylcellulose is preferably used.
凝集防止剤を含む反応促進剤は、２価の銅イオンを含む水溶液および還元剤の少なくとも一方に存在するのが好ましい。また、反応促進剤は、２価の銅イオンを還元する直前に、２価の銅イオンを含む水溶液および還元剤の少なくとも一方に添加してもよいし、まず、反応促進剤を含む水溶液を作製し、この水溶液の中に２価の銅イオンを含む水溶液または還元剤を加えた溶液を用意し、この反応促進剤と２価の銅イオンおよび還元剤の一方が存在する溶液に、２価の銅イオンおよび還元剤の他方を添加することによって、還元反応を行ってもよい。この還元反応では、反応促進剤としてのＡｇ粒子やＰｄ粒子の個数が銅粒子の粒子径を決定する主な因子になるため、反応の自由度があり、また、反応の再現性に優れている。 The reaction accelerator containing the aggregation inhibitor is preferably present in at least one of the aqueous solution containing divalent copper ions and the reducing agent. Moreover, the reaction accelerator may be added to at least one of the aqueous solution containing divalent copper ions and the reducing agent immediately before reducing the divalent copper ions, or first, an aqueous solution containing the reaction accelerator is prepared. Then, an aqueous solution containing divalent copper ions or a reducing agent is added to the aqueous solution, and a divalent copper ion and a reducing agent are added to the solution containing the reaction accelerator and one of the divalent copper ions and the reducing agent. You may perform a reductive reaction by adding the other of a copper ion and a reducing agent. In this reduction reaction, the number of Ag particles and Pd particles as reaction accelerators is the main factor determining the particle size of the copper particles, so there is a degree of freedom of reaction and excellent reproducibility of the reaction. .
反応促進剤の作製に使用するＰｄ原料またはＡｇ原料は、水溶性であり、入手し易く、取り扱い易いものであればよく、例えば、硝酸Ｐｄ、硝酸Ａｇ、硫酸Ａｇなどが挙げられる。 The Pd raw material or the Ag raw material used for the production of the reaction accelerator may be water-soluble, easily available, and easy to handle, and examples thereof include Pd nitrate, Ag nitrate, and sulfuric acid Ag.
また、反応促進剤の水溶液中のＡｇやＰｄのイオン濃度は、高過ぎると、還元反応により１０〜１００ｎｍのＡｇ粒子やＰｄ粒子を得ることが困難になり、低過ぎると、（仕込みの２価の銅イオン量や目的とする粒径にもよるが）添加する反応促進剤の量が多くなるため、０．００００１〜０．０１モル／Ｌであるのが好ましい。 Moreover, if the ion concentration of Ag or Pd in the aqueous solution of the reaction accelerator is too high, it will be difficult to obtain Ag particles or Pd particles of 10 to 100 nm by a reduction reaction, and if it is too low, (Depending on the amount of copper ions and the target particle size), the amount of the reaction accelerator to be added is increased, so 0.00001 to 0.01 mol / L is preferable.
ＡｇイオンまたはＰｄイオンの溶液を還元するために使用する還元剤は、なるべく強力な還元力を有するものであればよく、例えば、ヒドラジン類や水素化ホウ素化合物などが挙げられる。この還元剤の添加量は、化学量論的にＡｇイオンまたはＰｄイオンを還元することができる量以上であることが必要である。この還元剤の添加量が少ないと、十分な還元力が得られず、ＡｇやＰｄの粒子径が１０〜１００ｎｍの大きさにならず、一方、添加量が多過ぎると、次工程において銅に還元する際に残存する還元剤の還元力や溶液のｐＨなどの影響が無視できなくなる。そのため、ＡｇイオンまたはＰｄイオンの仕込み濃度の状態や還元条件（銅の仕込み条件など）により一概にはいえないが、還元剤の添加量は、ＡｇイオンまたはＰｄイオンに対して１〜４０当量であるのが好ましい。また、反応温度は、２０℃〜８０℃程度であればよい。 The reducing agent used for reducing the Ag ion or Pd ion solution may be any reducing agent as much as possible, and examples thereof include hydrazines and borohydride compounds. The amount of the reducing agent added needs to be at least the amount capable of reducing Ag ions or Pd ions stoichiometrically. If the amount of the reducing agent added is small, sufficient reducing power cannot be obtained, and the particle diameter of Ag or Pd is not as large as 10 to 100 nm. Effects such as the reducing power of the reducing agent remaining during the reduction and the pH of the solution cannot be ignored. Therefore, although it cannot be generally said depending on the state of the charged concentration of Ag ions or Pd ions and the reducing conditions (copper charged conditions, etc.), the addition amount of the reducing agent is 1 to 40 equivalents with respect to the Ag ions or Pd ions. Preferably there is. Moreover, the reaction temperature should just be about 20 degreeC-80 degreeC.
還元剤の添加方法は、溶液内の均一反応を実現する観点から、添加する溶液を一挙に添加するのが好ましい。具体的な添加時間は、反応溶液の攪拌方法（溶液の拡散速度）、反応スケールにより一概にはいえないが、速い程よく、例えば１分以内であるのが好ましい。また、還元の際に反応液を攪拌するのが好ましい。 As a method for adding the reducing agent, it is preferable to add the solutions to be added all at once from the viewpoint of realizing a uniform reaction in the solution. Although the specific addition time cannot be generally specified depending on the stirring method of the reaction solution (diffusion speed of the solution) and the reaction scale, it is preferable that the addition time is fast, for example, within 1 minute. Moreover, it is preferable to stir the reaction liquid during the reduction.
還元により得られたＡｇ粒子やＰｄ粒子の凝集を防ぐために、凝集防止剤としてポリエチレンイミンまたはメチルセルロースを添加するのが好ましい。凝集防止剤は、ＡｇイオンまたはＰｄイオンの還元前に添加してもよいし、還元終了後に添加してもよい。 In order to prevent aggregation of Ag particles and Pd particles obtained by reduction, it is preferable to add polyethyleneimine or methylcellulose as an aggregation inhibitor. The aggregation inhibitor may be added before the reduction of Ag ions or Pd ions, or may be added after the reduction is completed.
２価の銅イオンを銅まで還元する際に添加する還元剤の量は、化学量論的に２価の銅イオンを銅まで還元することができる量以上であることが必要である。この還元剤の量が多過ぎるとコスト的に不利になるので、２価の銅イオンの原料に対して１〜１０モルであるのが好ましい。 The amount of the reducing agent to be added when divalent copper ions are reduced to copper needs to be greater than or equal to the stoichiometric amount capable of reducing divalent copper ions to copper. If the amount of the reducing agent is too large, it is disadvantageous in terms of cost.
この還元反応時の攪拌方法としては、反応液が均一に混ざるような方法であればよく、例えば、マグネットスターラーにより攪拌する方法や、羽根を備え付けた攪拌棒を反応溶液中に設置して外部モーターにより回転させることにより攪拌する方法などが挙げられる。この還元時の反応温度は、２０〜１００℃程度であればよく、反応の制御性から４０〜８０℃であるのが好ましい。 As a stirring method at the time of the reduction reaction, any method may be used as long as the reaction solution is uniformly mixed. For example, a stirring method using a magnetic stirrer or a stirring rod equipped with a blade is installed in the reaction solution to provide an external motor. And the like. The reaction temperature during this reduction may be about 20 to 100 ° C., and is preferably 40 to 80 ° C. from the viewpoint of controllability of the reaction.
反応促進剤としてのＡｇ粒子やＰｄ粒子の割合は、生成したＡｇ粒子やＰｄ粒子の粒径（１０〜１００ｎｍ）、銅イオンの仕込み量および目的とする粒径（０．１〜０．５μｍ）から適宜決定すればよい。 The ratio of Ag particles and Pd particles as a reaction accelerator is as follows: the particle size of Ag particles and Pd particles produced (10 to 100 nm), the charged amount of copper ions, and the desired particle size (0.1 to 0.5 μm). It may be determined as appropriate.
銅への還元反応では、溶液内の均一反応を実現する観点から、添加する溶液を一挙に添加するのが好ましい。具体的な添加時間は、反応溶液の攪拌方法（溶液の拡散速度）、反応スケールにより一概にはいえないが、例えば１分以内であるのが好ましい。この還元反応では、２価の銅イオンを含む水溶液と還元剤を混合すると直ぐに反応が発生するため、長時間反応させる必要はなく、具体的には１０分以内でよい。 In the reduction reaction to copper, it is preferable to add the solutions to be added all at once from the viewpoint of realizing a uniform reaction in the solution. The specific addition time cannot be generally determined depending on the reaction solution stirring method (solution diffusion rate) and reaction scale, but is preferably within 1 minute, for example. In this reduction reaction, when an aqueous solution containing divalent copper ions and a reducing agent are mixed, the reaction occurs immediately. Therefore, it is not necessary to carry out the reaction for a long time, and specifically, it may be within 10 minutes.
このようにして得られた銅粉含有スラリーをろ過し、水洗することによって、塊状の銅ケーキが得られる。ろ過および水洗の方法としては、フィルタープレスなどにより粉体を固定した状態で水洗する方法や、スラリーをデカントし、その上澄み液を除去した後に純水を加えて攪拌し、その後、再びデカントして上澄み液を除去する操作を繰り返し行う方法や、ろ過後の銅粉をリパルプした後に再度ろ過する操作を繰り返し行う方法などのいずれでもよいが、銅粉体中に局所的に残留している不純物をできる限り除去することができる方法が好ましく、これにより、乾燥処理中の凝集を防止する効果や、銅粉の表面に存在する官能基の活性度合いが高まることにより脂肪酸を表面処理した際の脂肪酸や表面処理剤などの銅粉への付着率が高まる効果があると考えられる。その後、脂肪酸やベンゾトリアゾール（ＢＴＡ）などの防錆効果ある物質を低級アルコールなどに溶解し、水洗した銅ケーキに通液またはリパルプさせることにより、その物質で被覆してもよいし、また、銅ケーキの乾燥を早めるために、銅ケーキ中の水分を低級アルコールにより置換してもよい。また、得られた銅ケーキを、酸化させない雰囲気において乾燥（窒素雰囲気中の乾燥や真空乾燥）することによって銅微粒子を得ることができる。また、必要に応じて、乾式解砕処理、篩分け、風力分級などの処理を行ってもよい。 The copper powder-containing slurry thus obtained is filtered and washed with water to obtain a massive copper cake. As a method of filtration and washing with water, a method of washing with powder fixed by a filter press or the like, or decanting the slurry, removing the supernatant liquid, stirring with pure water, and then decanting again Either the method of repeatedly removing the supernatant liquid or the method of repeatedly filtering the filtered copper powder and then re-filtering it may be used, but impurities remaining locally in the copper powder may be removed. A method that can be removed as much as possible is preferable, whereby the effect of preventing aggregation during the drying treatment and the fatty acid when the fatty acid is surface-treated by increasing the activity of the functional groups present on the surface of the copper powder. It is thought that there is an effect of increasing the adhesion rate to the copper powder such as a surface treatment agent. Thereafter, a substance having an antirust effect such as fatty acid and benzotriazole (BTA) may be dissolved in a lower alcohol or the like, and coated with the substance by passing or repulping it into a washed copper cake. In order to accelerate the drying of the cake, the water in the copper cake may be replaced with a lower alcohol. Moreover, copper fine particles can be obtained by drying the obtained copper cake in an atmosphere that does not oxidize (drying in a nitrogen atmosphere or vacuum drying). Moreover, you may perform processes, such as a dry crushing process, sieving, and an air classification, as needed.
なお、２価の銅イオンを含む水溶液に、２価の銅イオンと錯体やキレートを形成する物質や、銅微粒子の凝集を抑制する分散剤を添加してもよい（但し、これらの添加により還元反応時に水酸化銅や亜酸化銅を経由するようなｐＨ領域にならないようにする必要がある）。例えば、クエン酸や酢酸などのカルボキシル基を有する物質、グリシンやアラニンなどのアミノ基とカルボキシル基を有する物質、ポリエチレンイミンなどのキレート剤、アラビアゴムやゼラチンなどの分散剤などを添加してもよい。 It should be noted that a substance that forms a complex or chelate with a divalent copper ion or a dispersant that suppresses aggregation of copper fine particles may be added to an aqueous solution containing divalent copper ions (however, reduction by these additions) It is necessary to avoid a pH range that passes through copper hydroxide or cuprous oxide during the reaction). For example, a substance having a carboxyl group such as citric acid or acetic acid, a substance having an amino group and a carboxyl group such as glycine or alanine, a chelating agent such as polyethyleneimine, a dispersant such as gum arabic or gelatin may be added. .
また、作製した銅粉を積層セラミックコンデンサの内部電極に使用する場合に、誘電体グリーンシートとともに焼成する際の銅粉の熱収縮挙動（焼結挙動）を変化させるために、誘電体に使用される金属化合物と同じ種類の金属を含む化合物（例えば、チタン酸バリウム、チタニア、アルミナ、シリカなど）を銅粉の表面に被着させてもよい（またはその化合物で銅粉の表面を被覆してもよい）。このような処理によって、銅粉を積層セラミックコンデンサの内部電極に使用する場合に、誘電体と銅粉の焼結挙動を合わせることが可能になり、その結果、誘電体と電極との剥離（デラミネーション）の発生による不良を防止することができる。 In addition, when the produced copper powder is used as an internal electrode of a multilayer ceramic capacitor, it is used for dielectrics to change the thermal shrinkage behavior (sintering behavior) of copper powder when fired together with the dielectric green sheet. A compound containing the same type of metal as the metal compound (for example, barium titanate, titania, alumina, silica, etc.) may be deposited on the surface of the copper powder (or by coating the surface of the copper powder with the compound) May be good). Such treatment makes it possible to match the sintering behavior of the dielectric and the copper powder when the copper powder is used as the internal electrode of the multilayer ceramic capacitor. Defects due to the occurrence of lamination can be prevented.
銅粉の表面に被着させる方法（または銅粉の表面を被覆する方法）は、生成した銅粒子を凝集させない方法であればよい。例えば、作製した銅粉をアルコール中に分散させた溶液に（誘電体材料を含む物質である）金属アルコキシドを加えて加水分解した後にろ過して乾燥する方法、銅粉と（誘電体材料を含む物質である）金属アルコキシド溶液とを混合する方法、誘電体として使用する物質（銅粉の粒子径と同じか、それ以下の粒子径のもの）と銅粉を乾式または湿式により混合する方法などがある。また、その被着量または被覆量は、内部電極の導電性を劣化させず且つ収縮挙動に効果がある量であればよく、例えば、銅粒子に対して０．１〜１０質量％程度であるのが好ましい。 The method of depositing on the surface of the copper powder (or the method of coating the surface of the copper powder) may be any method as long as the generated copper particles are not aggregated. For example, a method in which a metal alkoxide (which is a substance containing a dielectric material) is added to a solution in which the produced copper powder is dispersed in alcohol, hydrolyzed and then filtered and dried, and copper powder (including a dielectric material) A method of mixing a metal alkoxide solution (which is a substance), a method of mixing a substance to be used as a dielectric (having a particle diameter equal to or smaller than the particle diameter of copper powder) and copper powder in a dry or wet manner. is there. Further, the deposition amount or the coating amount may be an amount that does not deteriorate the conductivity of the internal electrode and has an effect on the shrinkage behavior, and is, for example, about 0.1 to 10% by mass with respect to the copper particles. Is preferred.
上述した本発明による導電性ペースト用銅粉の製造方法の実施の形態によって製造した導電性ペースト用銅粉は、単分散した微粒子で、粒度分布がシャープで、粗粒を含まず、形状が真球に近いものであり、積層セラミックコンデンサの内部電極の導電性ペースト用や外部電極の導電性ペースト用の銅粉として適した銅粉であり、この導電性ペースト用銅粉を用いて、公知の方法により導電性ペーストを製造することができる。このようにして製造した導電性ペーストは、電気的特性への悪影響を回避しながら電極の薄膜化を可能にし、積層セラミックコンデンサの内部電極用や外部電極用の導電性ペーストとして使用することができる。 The copper powder for conductive paste manufactured according to the above-described embodiment of the method for manufacturing copper powder for conductive paste according to the present invention is monodispersed fine particles, has a sharp particle size distribution, does not contain coarse particles, and has a true shape. It is close to a sphere, and is a copper powder suitable as a copper powder for a conductive paste for an internal electrode of a multilayer ceramic capacitor or a conductive paste for an external electrode. Using this copper powder for a conductive paste, A conductive paste can be produced by the method. The conductive paste produced in this way enables electrode thinning while avoiding adverse effects on electrical characteristics, and can be used as a conductive paste for internal electrodes and external electrodes of multilayer ceramic capacitors. .
また、本発明による導電性ペースト用銅粉の製造方法の実施の形態によって製造した導電性ペースト用銅粉は、レーザー回折式粒度分布測定装置によって測定された５０％粒径（Ｄ５０）が０．１〜０．５μｍ、検出の最大粒径（Ｄｍａｘ）が１．５μｍ以下であり、１０〜１００００ｐｐｍのＡｇおよびＰｄの少なくとも一方を含む。レーザー回折式粒度分布測定装置によって測定された５０％粒径（Ｄ５０）が０．１〜０．５μｍであれば、積層セラミックコンデンサなどの高容量化や小型化のために必要な内部電極の薄層化（近年では層の厚さ１．５μｍ以下）を実現することができる。また、検出の最大粒径（Ｄｍａｘ）が１．５μｍ以下であれば、内部電極と誘電体セラミックグリーンシートを積層させた際に、内部電極の薄層における粗粒の存在により誘電体層を突き破って絶縁不良を引き起こすおそれがない。さらに、１０〜１００００ｐｐｍのＡｇおよびＰｄの少なくとも一方を含むのは、上記の粒径の銅微粒子を得るために必要な反応促進剤に含まれるためである。１０ｐｐｍ未満では、上記の粒径の銅微粒子を得る上で困難になり、１００００ｐｐｍより多いと、コスト高になり、品質に悪影響を及ぼす可能性がある。 Further, the copper powder for conductive paste manufactured by the embodiment of the method for manufacturing copper powder for conductive paste according to the present invention has a 50% particle size (D 50 ) measured by a laser diffraction particle size distribution measuring device of 0. 0.1 to 0.5 μm, the maximum particle size (D max ) for detection is 1.5 μm or less, and contains at least one of 10 to 10000 ppm of Ag and Pd. If the 50% particle size (D 50 ) measured by a laser diffraction particle size distribution analyzer is 0.1 to 0.5 μm, the internal electrode necessary for high capacity and miniaturization of a multilayer ceramic capacitor and the like Thinning (in recent years, layer thickness of 1.5 μm or less) can be realized. Further, if the maximum particle size (D max ) of detection is 1.5 μm or less, the dielectric layer is formed due to the presence of coarse particles in the thin layer of the internal electrode when the internal electrode and the dielectric ceramic green sheet are laminated. There is no risk of breaking through and causing poor insulation. Further, the reason why it contains at least one of Ag and Pd of 10 to 10,000 ppm is that it is contained in a reaction accelerator necessary for obtaining copper fine particles having the above particle diameter. If it is less than 10 ppm, it is difficult to obtain copper fine particles having the above-mentioned particle diameter, and if it exceeds 10000 ppm, the cost is increased and the quality may be adversely affected.
また、上述した検出の最大粒径（Ｄｍａｘ）の存在と同様に、凝集粒子の存在も上記の内部電極の形成に悪影響を及ぼす。そのため、導電性ペースト用銅粉は、一次粒子（単体粒子）だけが個々に存在している形態であるのが好ましい。具体的には、電界放出形走査電子顕微鏡（ＳＥＭ）によって観測される単体粒子（一次粒子）の平均粒径（単体粒子径）に対して、レーザー回折式粒度分布測定装置によって観測される凝集粒子（二次粒子）の５０％粒径（凝集粒子径）の比（二次粒子径／一次粒子径）が２．０以下であるのが好ましい。 In addition, the presence of aggregated particles has an adverse effect on the formation of the internal electrode, similar to the presence of the maximum particle diameter (D max ) for detection described above. Therefore, the copper powder for conductive paste is preferably in a form in which only primary particles (single particles) are present individually. Specifically, agglomerated particles observed by a laser diffraction particle size distribution measuring device with respect to the average particle size (single particle size) of single particles (primary particles) observed by a field emission scanning electron microscope (SEM) The ratio (secondary particle diameter / primary particle diameter) of 50% particle diameter (aggregated particle diameter) of (secondary particles) is preferably 2.0 or less.
さらに、上述した検出の最大粒径（Ｄｍａｘ）の存在と同様に、結合または凝結粒子（連晶粒子）の存在も内部電極の形成に悪影響（粗大粒子の原因や電極形成時の膜密度の低下（粉体特性のＴＡＰ密度の低下））を及ぼす。なお、本明細書中において「凝集粒子」とは、静電気引力などの作用により物理的に単一の粒子が数個〜数十個集まって形成された一つの大きな粒子（還元反応後に生成された粒子）をいい、「結合または凝結粒子（連晶粒子）」とは、銅イオンの還元反応により略球状の粒子の表面に銅粒子が成長して歪んだ形状の粒子をいう。凝集粒子は、比較的弱い力により単一粒子（一次粒子）まで解砕して分散させることができるが、結合または凝結粒子（連晶粒子）は、強力な外力を加えないと解砕する（剥がす）ことができず、解砕することができたとしても、剥がれた部分の面が露出することによって、粒子の表面特性が元からある表面特性と異なり、導電性ペーストに使用した際の悪影響や、解砕作業やペースト混錬作業において良好に分散させることができず、粒子の付着が生じ（結合または凝結粒子が一つの粗大粒子になり）、さらに粗大な粒子になる可能性がある。そのため、ＳＥＭによって観測される銅粒子の中で単一の略球状の銅粒子の個数の割合が９０％以上であるのが好ましい。 Further, similar to the presence of the maximum particle size (D max ) of detection described above, the presence of bound or condensed particles (intergranular particles) has an adverse effect on the formation of internal electrodes (cause of coarse particles and film density at the time of electrode formation). Reduction (decrease in TAP density of powder properties). In the present specification, “aggregated particles” means one large particle (generated after the reduction reaction) formed by collecting several to tens of physical single particles by an action such as electrostatic attraction. The term “bonded or condensed particles (continuous crystal particles)” refers to particles having a shape that is distorted by the growth of copper particles on the surface of substantially spherical particles due to the reduction reaction of copper ions. Aggregated particles can be crushed and dispersed to a single particle (primary particle) with relatively weak force, but bonded or agglomerated particles (intergranular particles) are crushed without applying a strong external force ( Even if it can not be peeled off and can be crushed, the surface of the peeled part is exposed, and the surface characteristics of the particles differ from the original surface characteristics. In addition, it cannot be dispersed well in the pulverization operation or paste kneading operation, and particle adhesion occurs (bonded or coagulated particles become one coarse particle), which may result in coarser particles. Therefore, it is preferable that the ratio of the number of single substantially spherical copper particles among the copper particles observed by SEM is 90% or more.
以下、本発明による導電性ペースト用銅粉およびその製造方法の実施例について詳細に説明する。 Hereinafter, the Example of the copper powder for electrically conductive paste by this invention and its manufacturing method is described in detail.
［実施例１］
まず、５Ｌの反応槽内に純水３４１０ｇを入れ、反応槽の上部から５Ｌ／分の流量で窒素を供給して反応槽内を窒素雰囲気に維持し、反応槽内の攪拌棒の回転速度を２００ｒｐｍに調整し、反応槽内の純水の温度を２５℃に調整した。次に、硝酸パラジウム（ＩＩ）（和光純薬工業株式会社製）０．０９２２ｇを純水２５０ｇに溶解した溶液を反応槽内に入れ、２分間攪拌して均一に混合した。次に、還元剤として０．１％ヒドラジン水和物溶液（大塚化学株式会社製の８０％ヒドラジン水和物を純水により希釈した溶液）１００ｇを反応槽内の溶液に一挙に添加して還元反応を行った。次に、凝集防止剤としてポリエチレンイミン（ＰＥＩ）（和光純薬工業株式会社製、平均分子量１００００）０．４２５６ｇを純水２１０ｇに溶解した溶液を反応槽内の溶液に添加し、１０分間攪拌して反応促進剤の溶液を得た。得られた溶液中の反応促進剤は、透き通った薄い黒色で、この溶液を透過電子顕微鏡（ＴＥＭ）で観察したところ、溶液中の反応促進剤は平均粒径２５ｎｍの粒子であった。
[Example 1]
First, 3410 g of pure water was put in a 5 L reaction tank, nitrogen was supplied from the upper part of the reaction tank at a flow rate of 5 L / min to maintain the inside of the reaction tank in a nitrogen atmosphere, and the rotation speed of the stirring rod in the reaction tank was changed. The temperature was adjusted to 200 rpm, and the temperature of pure water in the reaction vessel was adjusted to 25 ° C. Next, a solution in which 0.0922 g of palladium nitrate (II) (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 250 g of pure water was placed in the reaction vessel, and stirred for 2 minutes to mix uniformly. Next, 100 g of a 0.1% hydrazine hydrate solution (a solution obtained by diluting 80% hydrazine hydrate manufactured by Otsuka Chemical Co., Ltd. with pure water) as a reducing agent was added to the solution in the reaction tank at once and reduced. Reaction was performed. Next, a solution prepared by dissolving 0.4256 g of polyethyleneimine (PEI) (manufactured by Wako Pure Chemical Industries, Ltd., average molecular weight 10,000) as an aggregation inhibitor in 210 g of pure water is added to the solution in the reaction vessel and stirred for 10 minutes. Thus, a reaction accelerator solution was obtained. The reaction accelerator in the obtained solution was clear and light black, and when this solution was observed with a transmission electron microscope (TEM), the reaction accelerator in the solution was a particle having an average particle diameter of 25 nm.
また、２Ｌビーカーに純水６００ｇを入れ、純水の温度を６０℃に調整しながら、還元剤としてＬ−アスコルビン酸（和光純薬工業株式会社製）３３．０ｇを添加して溶解させて、還元剤溶液を得た。この還元剤溶液に上記の反応促進剤４４７ｇを計量して添加した後、１分間攪拌して均一になるように混合した。 Further, 600 g of pure water was put into a 2 L beaker, and while adjusting the temperature of pure water to 60 ° C., 33.0 g of L-ascorbic acid (manufactured by Wako Pure Chemical Industries, Ltd.) was added and dissolved as a reducing agent. A reducing agent solution was obtained. 447 g of the above reaction accelerator was weighed and added to this reducing agent solution, and then stirred for 1 minute and mixed uniformly.
また、５Ｌの反応槽内に純水３０００ｇを入れ、反応槽の上部から５Ｌ／分の流量で窒素を供給して反応槽内を窒素雰囲気に維持し、反応槽内の攪拌棒の回転速度を２９０ｒｐｍに調整し、反応槽内の純水の温度を６０℃に調整しながら、硫酸銅５水和物（小名浜製錬株式会社製）３７．５ｇを添加して溶解させて、２価の銅イオンを含む水溶液を得た。 Also, 3000 g of pure water is put into a 5 L reaction tank, nitrogen is supplied from the upper part of the reaction tank at a flow rate of 5 L / min to maintain the inside of the reaction tank in a nitrogen atmosphere, and the rotation speed of the stirring rod in the reaction tank is adjusted. While adjusting to 290 rpm and adjusting the temperature of pure water in the reaction vessel to 60 ° C., 37.5 g of copper sulfate pentahydrate (manufactured by Onahama Smelting Co., Ltd.) was added and dissolved to divalent copper. An aqueous solution containing ions was obtained.
次に、この２価の銅イオンを含む水溶液が入っている反応槽の上部から、上記の反応促進剤を添加した還元剤溶液を一挙に添加して還元反応を行った。この還元剤溶液を添加した直後に銅粒子が発生したのが確認された。なお、添加した反応促進剤中のＰｄ量はＣｕに対して約５００ｐｐｍである。反応槽内の溶液を連続して攪拌し、その状態のまま５分間熟成させた後、攪拌を止め、洗浄し、乾燥させて、銅微粒子を得た。 Next, from the upper part of the reaction vessel containing the aqueous solution containing the divalent copper ions, the reducing agent solution added with the above reaction accelerator was added all at once to perform a reduction reaction. It was confirmed that copper particles were generated immediately after this reducing agent solution was added. The amount of Pd in the added reaction accelerator is about 500 ppm with respect to Cu. The solution in the reaction vessel was continuously stirred and aged for 5 minutes in that state, and then the stirring was stopped, washed and dried to obtain copper fine particles.
［実施例２］
反応促進剤を還元剤溶液に添加せずに２価の銅イオンを含む水溶液に添加した後、この反応促進剤が添加された２価の銅イオンを含む水溶液に還元剤溶液を添加した以外は、実施例１と同様の方法により、銅微粒子を得た。
[Example 2]
The reaction accelerator is not added to the reducing agent solution but added to the aqueous solution containing divalent copper ions, and then the reducing agent solution is added to the aqueous solution containing divalent copper ions to which the reaction accelerator is added. By the same method as in Example 1, copper fine particles were obtained.
［実施例３］
還元剤としてＬ−アスコルビン酸の代わりにＤ−エリソルビン酸（和光純薬工業株式会社製）を使用した以外は、実施例１と同様の方法により、銅微粒子を得た。
[Example 3]
Copper fine particles were obtained by the same method as in Example 1 except that D-erythorbic acid (Wako Pure Chemical Industries, Ltd.) was used instead of L-ascorbic acid as the reducing agent.
［実施例４］
２価の銅イオンの原料として硫酸銅５水和物の代わりに硝酸銅（ＩＩ）３水和物（片山化学工業株式会社製）３６．２ｇを使用した以外は、実施例１と同様の方法により、銅微粒子を得た。
[Example 4]
The same method as in Example 1 except that 36.2 g of copper nitrate (II) trihydrate (manufactured by Katayama Chemical Co., Ltd.) was used instead of copper sulfate pentahydrate as a raw material for divalent copper ions. Thus, copper fine particles were obtained.
［実施例５］
還元剤溶液および２価の銅イオンを含む水溶液を作製する際の温度をそれぞれ８０℃にした以外は、実施例１と同様の方法により、銅微粒子を得た。
[Example 5]
Copper fine particles were obtained by the same method as in Example 1 except that the temperature for preparing the reducing agent solution and the aqueous solution containing divalent copper ions was 80 ° C., respectively.
［実施例６］
還元剤溶液および２価の銅イオンを含む水溶液を作製する際の温度をそれぞれ４０℃のした以外は、実施例１と同様の方法により、銅微粒子を得た。
[Example 6]
Copper fine particles were obtained by the same method as in Example 1 except that the temperature for preparing the reducing agent solution and the aqueous solution containing divalent copper ions was 40 ° C., respectively.
［実施例７］
２価の銅イオンを含む水溶液に、さらにポリエチレンイミン（和光純薬工業株式会社製、平均分子量１００００）を銅の仕込み量に対して１質量％になるように添加した以外は、実施例１と同様の方法により、銅微粒子を得た。
[Example 7]
Example 1 except that polyethyleneimine (manufactured by Wako Pure Chemical Industries, Ltd., average molecular weight 10,000) was further added to an aqueous solution containing divalent copper ions so as to be 1% by mass with respect to the charged amount of copper. By the same method, copper fine particles were obtained.
［実施例８］
２価の銅イオンを含む水溶液に、さらにグリシン（関東化学株式会社製）０．１２５モルを添加した以外は、実施例１と同様の方法により、銅微粒子を得た。
[Example 8]
Copper fine particles were obtained in the same manner as in Example 1 except that 0.125 mol of glycine (manufactured by Kanto Chemical Co., Inc.) was further added to the aqueous solution containing divalent copper ions.
［実施例９］
２価の銅イオンを含む水溶液に、さらにアラビアゴム（和光純薬工業株式会社製）を銅の仕込み量に対して５質量％になるように添加した以外は、実施例１と同様の方法により、銅微粒子を得た。
[Example 9]
According to the same method as in Example 1, except that gum arabic (manufactured by Wako Pure Chemical Industries, Ltd.) was further added to the aqueous solution containing divalent copper ions so as to be 5% by mass with respect to the charged amount of copper. Copper fine particles were obtained.
［実施例１０］
反応促進剤の溶液を作製する際に硝酸パラジウムと凝集防止剤としてのポリエチレンイミンを同時に添加した以外は、実施例１と同様の方法により、銅微粒子を得た。なお、本実施例で得られた反応促進剤は、実施例１と比べて薄い色であり、この反応促進剤の溶液をＴＥＭで観察したところ、溶液中の反応促進剤は平均粒径２０ｎｍの粒子であった。
[Example 10]
Copper fine particles were obtained by the same method as in Example 1 except that palladium nitrate and polyethyleneimine as an anti-aggregation agent were added simultaneously when preparing the reaction accelerator solution. In addition, the reaction accelerator obtained in the present example is lighter in color than in Example 1. When the solution of this reaction accelerator was observed with TEM, the reaction accelerator in the solution had an average particle diameter of 20 nm. It was a particle.
［実施例１１］
反応促進剤の溶液を作製する際に硝酸パラジウムと還元剤（ヒドラジン水和物溶液）と凝集防止剤（ポリエチレンイミン）の量を８倍にし、反応促進剤が添加された還元剤溶液を作製する際に還元剤溶液に反応促進剤５５．９ｇを計量して添加（添加した反応促進剤中のＰｄ量がＣｕに対して約５００ｐｐｍになるように）した以外は、実施例１と同様の方法により、銅微粒子を得た。なお、本実施例で得られた反応促進剤は、実施例１と比べて濃いグレーの溶液であり、この反応促進剤の溶液をＴＥＭで観察したところ、溶液中の反応促進剤は平均粒径２８ｎｍの粒子であった。
[Example 11]
When preparing the solution of the reaction accelerator, the amount of palladium nitrate, reducing agent (hydrazine hydrate solution) and anti-aggregation agent (polyethyleneimine) is increased 8 times to prepare a reducing agent solution to which the reaction accelerator is added. At this time, the same method as in Example 1 except that 55.9 g of the reaction accelerator was weighed and added to the reducing agent solution (so that the amount of Pd in the added reaction accelerator was about 500 ppm with respect to Cu). Thus, copper fine particles were obtained. The reaction accelerator obtained in this example is a dark gray solution compared to Example 1. When the solution of this reaction accelerator was observed with TEM, the reaction accelerator in the solution had an average particle size. The particles were 28 nm.
［実施例１２］
２価の銅イオンを含む水溶液を作製する際に硫酸銅５水和物（小名浜製錬株式会社製）の添加量を１８７．３ｇにし、還元剤溶液を作製する際にＬ−アスコルビン酸（和光純薬工業株式会社製）の添加量を１６５．１ｇにし、還元剤溶液に添加した反応促進剤の量を２７７．４ｇにした以外は、実施例１と同様の方法により、銅微粒子を得た。
[Example 12]
When preparing an aqueous solution containing divalent copper ions, the addition amount of copper sulfate pentahydrate (manufactured by Onahama Smelting Co., Ltd.) was 187.3 g, and when preparing a reducing agent solution, L-ascorbic acid (Japanese Copper fine particles were obtained in the same manner as in Example 1 except that the amount added was 165.1 g and the amount of the reaction accelerator added to the reducing agent solution was 277.4 g. .
［実施例１３］
反応促進剤を添加した還元剤溶液を２価の銅イオンを含む水溶液に添加する代わりに、反応促進剤を添加した還元剤溶液に２価の銅イオンを含む水溶液を添加した以外は、実施例１と同様の方法により、銅微粒子を得た。すなわち、５Ｌの反応槽内に純水３０００ｇを入れ、反応槽の上部から５Ｌ／分の流量で窒素を供給して反応槽内を窒素雰囲気に維持し、反応槽内の攪拌棒の回転速度を２９０ｒｐｍに調整し、反応槽内の純水の温度を６０℃に調整しながら、Ｌ−アスコルビン酸（和光純薬工業株式会社製）３３．０ｇを添加して溶解させて、還元剤溶液を得た。また、２Ｌビーカーに純水６００ｇを入れ、純水の温度を６０℃に調整しながら、硫酸銅５水和物（小名浜製錬社製）３７．５ｇを添加して溶解させて、２価の銅イオンを含む水溶液を得た。
[Example 13]
Example except that the reducing agent solution added with the reaction accelerator was added to the aqueous solution containing divalent copper ions instead of adding the aqueous solution containing divalent copper ions to the reducing agent solution added with the reaction accelerator. In the same manner as in No. 1, copper fine particles were obtained. That is, 3000 g of pure water is put into a 5 L reaction tank, nitrogen is supplied from the upper part of the reaction tank at a flow rate of 5 L / min to maintain the inside of the reaction tank in a nitrogen atmosphere, and the rotation speed of the stirring rod in the reaction tank is increased. Adjusting to 290 rpm and adjusting the temperature of pure water in the reaction vessel to 60 ° C., 33.0 g of L-ascorbic acid (manufactured by Wako Pure Chemical Industries, Ltd.) is added and dissolved to obtain a reducing agent solution. It was. Further, 600 g of pure water was put into a 2 L beaker, and 37.5 g of copper sulfate pentahydrate (manufactured by Onahama Smelting Co., Ltd.) was added and dissolved while adjusting the temperature of the pure water to 60 ° C. An aqueous solution containing copper ions was obtained.
［実施例１４］
まず、反応槽内に純水１９００ｇを入れ、反応槽の上部から５Ｌ／分の流量で窒素を供給して反応槽内を窒素雰囲気に維持し、反応槽内の攪拌棒の回転速度を２００ｒｐｍに調整し、反応槽内の純水の温度を２５℃に調整した。次に、硝酸銀（関東化学株式会社製）０．３４ｇを純水２５０ｇに溶解した溶液を反応槽内に入れ、２分間攪拌して均一に混合した。次に、還元剤として０．１％ヒドラジン水和物溶液（大塚化学株式会社製の８０％ヒドラジン水和物を純水により希釈した溶液）６２５ｇを反応槽内の溶液に一挙に添加して還元反応を行った。次に、凝集防止剤としてポリエチレンイミン（和光純薬工業株式会社製、平均分子量１００００）２．１６ｇを純水１０８０ｇに溶解した溶液を反応槽内の溶液に添加し、１０分間攪拌して反応促進剤溶液を得た。得られた反応促進剤をＴＥＭで観察したところ、溶液中の反応促進剤は平均粒径６０ｎｍの粒子であった。
[Example 14]
First, 1900 g of pure water is put into the reaction tank, nitrogen is supplied from the upper part of the reaction tank at a flow rate of 5 L / min to maintain the inside of the reaction tank in a nitrogen atmosphere, and the rotation speed of the stirring rod in the reaction tank is set to 200 rpm. The temperature of pure water in the reaction vessel was adjusted to 25 ° C. Next, a solution in which 0.34 g of silver nitrate (manufactured by Kanto Chemical Co., Ltd.) was dissolved in 250 g of pure water was placed in the reaction vessel and stirred for 2 minutes to mix uniformly. Next, 625 g of a 0.1% hydrazine hydrate solution (80% hydrazine hydrate manufactured by Otsuka Chemical Co., Ltd. diluted with pure water) as a reducing agent was added to the solution in the reaction tank at once and reduced. Reaction was performed. Next, a solution obtained by dissolving 2.16 g of polyethyleneimine (manufactured by Wako Pure Chemical Industries, Ltd., average molecular weight 10,000) as a coagulation inhibitor in 1080 g of pure water is added to the solution in the reaction vessel, and stirred for 10 minutes to accelerate the reaction. An agent solution was obtained. When the obtained reaction accelerator was observed with TEM, the reaction accelerator in the solution was particles having an average particle diameter of 60 nm.
また、１Ｌビーカーに純水６００ｇを入れ、純水の温度を６０℃に調整しながら、還元剤としてＬ−アスコルビン酸（和光純薬工業株式会社製）３３．０ｇを添加して溶解させて、還元剤溶液を得た。この還元剤溶液に上記の反応促進剤８７５ｇを計量して添加した後、１分間攪拌して均一になるように混合した。 Moreover, 600 g of pure water was put into a 1 L beaker, and while adjusting the temperature of pure water to 60 ° C., 33.0 g of L-ascorbic acid (manufactured by Wako Pure Chemical Industries, Ltd.) was added and dissolved as a reducing agent. A reducing agent solution was obtained. 875 g of the above reaction accelerator was weighed and added to this reducing agent solution, and then stirred for 1 minute and mixed uniformly.
また、５Ｌの反応槽内に純水２５００ｇを入れ、反応槽の上部から５Ｌ／分の流量で窒素を供給して反応槽内を窒素雰囲気に維持し、反応槽内の攪拌棒の回転速度を２９０ｒｐｍに調整し、反応槽内の純水の温度を６０℃に調整しながら、硫酸銅５水和物（小名浜製錬株式会社製）３７．５ｇを添加して溶解させて、２価の銅イオンを含む水溶液を得た。 In addition, 2500 g of pure water is put into a 5 L reaction tank, nitrogen is supplied from the upper part of the reaction tank at a flow rate of 5 L / min to maintain the inside of the reaction tank in a nitrogen atmosphere, and the rotation speed of the stirring rod in the reaction tank is increased. While adjusting to 290 rpm and adjusting the temperature of pure water in the reaction vessel to 60 ° C., 37.5 g of copper sulfate pentahydrate (manufactured by Onahama Smelting Co., Ltd.) was added and dissolved to divalent copper. An aqueous solution containing ions was obtained.
次に、この２価の銅イオンを含む水溶液が入っている反応槽の上部から、上記の反応促進剤を添加した還元剤溶液を一挙に添加して還元反応を行った。この還元剤溶液を添加した直後に銅粒子が発生したのが確認された。なお、添加した反応促進剤中のＡｇ量はＣｕに対して約５０００ｐｐｍである。反応槽内の溶液を連続して攪拌し、その状態のまま５分間熟成させた後、攪拌を止め、洗浄し、乾燥させて、銅微粒子を得た。 Next, from the upper part of the reaction vessel containing the aqueous solution containing the divalent copper ions, the reducing agent solution added with the above reaction accelerator was added all at once to perform a reduction reaction. It was confirmed that copper particles were generated immediately after this reducing agent solution was added. The amount of Ag in the added reaction accelerator is about 5000 ppm with respect to Cu. The solution in the reaction vessel was continuously stirred and aged for 5 minutes in that state, and then the stirring was stopped, washed and dried to obtain copper fine particles.
［実施例１５］
まず、反応槽内に純水１９００ｇを入れ、反応槽の上部から５Ｌ／分の流量で窒素を供給して反応槽内を窒素雰囲気に維持し、反応槽内の攪拌棒の回転速度を２００ｒｐｍに調整し、反応槽内の純水の温度を２５℃に調整した。次に、硝酸銀（関東化学株式会社製）０．３４ｇを純水２５０ｇに溶解した溶液を反応槽内に入れ、２分間攪拌して均一に混合した。次に、還元剤として水素化ホウ素ナトリウム（和光純薬工業株式会社製）０．４７５ｇを純水６２５ｇに溶解した溶液を反応槽内の溶液に一挙に添加して還元反応を行った。次に、凝集防止剤としてポリエチレンイミン（和光純薬工業株式会社製、平均分子量１００００）２．１６ｇを純水１０８０ｇに溶解した溶液を反応槽内の溶液に添加し、１０分間攪拌して、反応促進剤溶液を得た。得られた反応促進剤をＴＥＭで観察したところ、溶液中の反応促進剤は平均粒径５０ｎｍの粒子であった。
[Example 15]
First, 1900 g of pure water is put into the reaction tank, nitrogen is supplied from the upper part of the reaction tank at a flow rate of 5 L / min to maintain the inside of the reaction tank in a nitrogen atmosphere, and the rotation speed of the stirring rod in the reaction tank is set to 200 rpm. The temperature of pure water in the reaction vessel was adjusted to 25 ° C. Next, a solution in which 0.34 g of silver nitrate (manufactured by Kanto Chemical Co., Ltd.) was dissolved in 250 g of pure water was placed in the reaction vessel and stirred for 2 minutes to mix uniformly. Next, a solution obtained by dissolving 0.475 g of sodium borohydride (manufactured by Wako Pure Chemical Industries, Ltd.) as a reducing agent in 625 g of pure water was added to the solution in the reaction tank all at once to perform a reduction reaction. Next, a solution obtained by dissolving 2.16 g of polyethyleneimine (manufactured by Wako Pure Chemical Industries, Ltd., average molecular weight 10,000) as a coagulation inhibitor in 1080 g of pure water is added to the solution in the reaction vessel, and stirred for 10 minutes to react. An accelerator solution was obtained. When the obtained reaction accelerator was observed with TEM, the reaction accelerator in the solution was particles having an average particle diameter of 50 nm.
また、１Ｌビーカーに純水６００ｇを入れ、純水の温度を６０℃に調整しながら、硫酸銅５水和物（小名浜製錬株式会社製）１２．５ｇを添加して溶解させて、２価の銅イオンを含む水溶液を得た。 In addition, 600 g of pure water was put into a 1 L beaker, and 12.5 g of copper sulfate pentahydrate (manufactured by Onahama Smelting Co., Ltd.) was added and dissolved while adjusting the temperature of pure water to 60 ° C. An aqueous solution containing copper ions was obtained.
また、５Ｌの反応槽内に純水１２５０ｇを入れ、反応槽の上部から５Ｌ／分の流量で窒素を供給して反応槽内を窒素雰囲気に維持し、反応槽内の攪拌棒の回転速度を２００ｒｐｍに調整し、反応槽内の純水の温度を６０℃に調整しながら、還元剤としてＬ−アスコルビン酸（和光純薬工業株式会社製）９９．０ｇを添加して溶解させて、還元剤溶液を得た。この還元剤溶液に上記の反応促進剤２０９５ｇを計量して添加した後、１分間攪拌して均一になるように混合した。 Moreover, 1250 g of pure water is put in a 5 L reaction tank, nitrogen is supplied from the upper part of the reaction tank at a flow rate of 5 L / min to maintain the inside of the reaction tank in a nitrogen atmosphere, and the rotation speed of the stirring rod in the reaction tank is adjusted. While adjusting to 200 rpm and adjusting the temperature of pure water in the reaction vessel to 60 ° C., 99.0 g of L-ascorbic acid (manufactured by Wako Pure Chemical Industries, Ltd.) is added and dissolved as a reducing agent. A solution was obtained. To this reducing agent solution, 2095 g of the above reaction accelerator was weighed and added, and stirred for 1 minute to mix uniformly.
次に、この反応促進剤が添加された還元剤溶液が入っている反応槽の上部から、上記の２価の銅イオンを含む水溶液を一挙に添加して還元反応を行った。この反応促進剤を添加した還元剤溶液を添加した直後に銅粒子が発生したのが確認された。なお、添加した反応促進剤中のＡｇ量はＣｕに対して約４０００ｐｐｍである。反応槽内の溶液を連続して攪拌し、その状態のまま５分間熟成させた後、攪拌を止め、洗浄し、乾燥させて、銅微粒子を得た。 Next, the above-described aqueous solution containing divalent copper ions was added all at once from the upper part of the reaction tank containing the reducing agent solution to which the reaction accelerator was added, and a reduction reaction was performed. It was confirmed that copper particles were generated immediately after the addition of the reducing agent solution containing the reaction accelerator. In addition, the Ag amount in the added reaction accelerator is about 4000 ppm with respect to Cu. The solution in the reaction vessel was continuously stirred and aged for 5 minutes in that state, and then the stirring was stopped, washed and dried to obtain copper fine particles.
［実施例１６］
まず、５Ｌの反応槽内に純水２５６０ｇを入れ、反応槽の上部から５Ｌ／分の流量で窒素を供給して反応槽内を窒素雰囲気に維持し、反応槽内の攪拌棒の回転速度を２００ｒｐｍに調整し、反応槽内の純水の温度を２５℃に調整した。次に、硝酸銀（関東化学株式会社製）０．２１６ｇを純水１００ｇに溶解した溶液を反応槽内に入れ、２分間攪拌して均一に混合した。次に、還元剤として８０％ヒドラジン水和物（大塚化学株式会社製）０．４９８ｇを純水１００ｇに溶解した溶液を反応槽内の溶液に一挙に添加して還元反応を行った。次に、凝集防止剤としてポリエチレンイミン（和光純薬工業株式会社製、平均分子量１００００）１．３７３ｇを純水５００ｇに溶解した溶液を反応槽内の溶液に添加し、１０分間攪拌して、反応促進剤の溶液を得た。得られた反応促進剤の溶液をＴＥＭで観察したところ、溶液中の反応促進剤は平均粒径５５ｎｍの粒子であった。
[Example 16]
First, 2560 g of pure water is put in a 5 L reaction tank, nitrogen is supplied from the upper part of the reaction tank at a flow rate of 5 L / min to maintain the inside of the reaction tank in a nitrogen atmosphere, and the rotation speed of the stirring rod in the reaction tank is increased. The temperature was adjusted to 200 rpm, and the temperature of pure water in the reaction vessel was adjusted to 25 ° C. Next, a solution obtained by dissolving 0.216 g of silver nitrate (manufactured by Kanto Chemical Co., Ltd.) in 100 g of pure water was placed in a reaction vessel and stirred for 2 minutes to uniformly mix. Next, a reductive reaction was performed by adding a solution obtained by dissolving 0.498 g of 80% hydrazine hydrate (manufactured by Otsuka Chemical Co., Ltd.) as a reducing agent in 100 g of pure water all at once to the solution in the reaction vessel. Next, a solution obtained by dissolving 1.373 g of polyethyleneimine (manufactured by Wako Pure Chemical Industries, Ltd., average molecular weight 10000) as an agglomeration inhibitor in 500 g of pure water is added to the solution in the reaction vessel and stirred for 10 minutes to react. An accelerator solution was obtained. When the obtained solution of the reaction accelerator was observed with TEM, the reaction accelerator in the solution was particles having an average particle diameter of 55 nm.
また、１Ｌビーカーに純水６００ｇを入れ、純水の温度を６０℃に調整しながら、還元剤としてＬ−アスコルビン酸（和光純薬工業株式会社製）１１８．９ｇを添加して溶解させて、還元剤溶液を得た。 Further, 600 g of pure water was put into a 1 L beaker, and 118.9 g of L-ascorbic acid (manufactured by Wako Pure Chemical Industries, Ltd.) was added and dissolved as a reducing agent while adjusting the temperature of the pure water to 60 ° C. A reducing agent solution was obtained.
また、１Ｌビーカーに純水６００ｇを入れ、純水の温度を６０℃に調整しながら、硫酸銅５水和物（小名浜製錬株式会社製）１３４．８ｇを添加して溶解させて、２価の銅イオンを含む水溶液を得た。 Further, 600 g of pure water was put into a 1 L beaker, and 134.8 g of copper sulfate pentahydrate (manufactured by Onahama Smelting Co., Ltd.) was added and dissolved while adjusting the temperature of pure water to 60 ° C. An aqueous solution containing copper ions was obtained.
次に、上記の反応促進剤の溶液が入っている５Ｌの反応槽内の攪拌棒の回転速度を２９０ｒｐｍに調整し、反応槽内の純水の温度を６０℃に調整しながら、上記の還元剤溶液を添加して、５分間攪拌して均一になるように混合した後、上記の２価の銅イオンを含む水溶液を一挙に添加して還元反応を行った。この２価の銅イオンを含む水溶液を添加した直後に銅粒子が発生したのが確認された。なお、添加した反応促進剤中のＡｇ量はＣｕに対して約４０００ｐｐｍである。その後、反応槽内の溶液を連続して攪拌し、その状態のまま５分間熟成させた後、攪拌を止め、洗浄し、乾燥させて、銅微粒子を得た。 Next, while adjusting the rotation speed of the stirring rod in the 5 L reaction vessel containing the above reaction accelerator solution to 290 rpm and adjusting the temperature of pure water in the reaction vessel to 60 ° C., the above reduction After adding the agent solution and stirring for 5 minutes to mix uniformly, the aqueous solution containing the above divalent copper ions was added all at once to perform a reduction reaction. It was confirmed that copper particles were generated immediately after the addition of the aqueous solution containing divalent copper ions. In addition, the Ag amount in the added reaction accelerator is about 4000 ppm with respect to Cu. Thereafter, the solution in the reaction vessel was continuously stirred and aged for 5 minutes in that state, and then the stirring was stopped, washed and dried to obtain copper fine particles.
［実施例１７］
反応促進剤を作製する際の温度を４０℃にした以外は、実施例１６と同様の方法により、銅微粒子を得た。なお、得られた反応促進剤の溶液をＴＥＭで観察したところ、溶液中の反応促進剤は平均粒径５５ｎｍの粒子であった。
[Example 17]
Copper fine particles were obtained by the same method as in Example 16 except that the temperature at the time of preparing the reaction accelerator was 40 ° C. In addition, when the solution of the obtained reaction accelerator was observed with TEM, the reaction accelerator in the solution was a particle having an average particle diameter of 55 nm.
［実施例１８］
反応促進剤を作製する際に添加するポリエチレンイミンの量を０．１３７ｇとし、還元剤としてエリソルビン酸を使用した以外は、実施例１６と同様の方法により、銅微粒子を得た。なお、得られた反応促進剤の溶液をＴＥＭで観察したところ、溶液中の反応促進剤は平均粒径７０ｎｍの粒子であった。
[Example 18]
Copper fine particles were obtained by the same method as in Example 16 except that the amount of polyethyleneimine added when preparing the reaction accelerator was 0.137 g and erythorbic acid was used as the reducing agent. In addition, when the solution of the obtained reaction accelerator was observed with TEM, the reaction accelerator in the solution was a particle having an average particle diameter of 70 nm.
［実施例１９］
反応促進剤を作製する際に凝集防止剤としてポリエチレンイミンの代わりにメチルセルロース（和光純薬工業株式会社製のメチルセルロース４０００）１．３７３ｇを使用した以外は、実施例１６と同様の方法により、銅微粒子を得た。なお、得られた反応促進剤の溶液をＴＥＭで観察したところ、溶液中の反応促進剤は平均粒径４５ｎｍの粒子であった。
[Example 19]
Copper fine particles were prepared in the same manner as in Example 16 except that 1.373 g of methylcellulose (methylcellulose 4000 manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of polyethyleneimine as an aggregation inhibitor when preparing the reaction accelerator. Got. In addition, when the solution of the obtained reaction accelerator was observed by TEM, the reaction accelerator in the solution was a particle having an average particle diameter of 45 nm.
［実施例２０］
実施例１６で得られた銅粒子１０ｇとイソプロピルアルコール１００ｇとを２００ｍＬビーカー中で十分に攪拌して混合した溶液に、エチルアセトアセテートアルミニウムジイソプロピレート（川研ファインケミカル社製のＳ−７５Ｐ）０．６６６ｇを添加して、１時間攪拌した後、攪拌を継続しながら純水５ｇを１０分間で添加した。純水の添加が終了した後、さらに１時間攪拌し、その後、ろ過、乾燥して、誘電体に使用される金属化合物としてＡｌ化合物が被着した銅粉（またはＡｌ化合物で被覆された銅粉）を得た。
[Example 20]
To a solution obtained by sufficiently stirring and mixing 10 g of the copper particles obtained in Example 16 and 100 g of isopropyl alcohol in a 200 mL beaker, ethyl acetoacetate aluminum diisopropylate (S-75P manufactured by Kawaken Fine Chemical Co.) After adding 666 g and stirring for 1 hour, 5 g of pure water was added over 10 minutes while continuing stirring. After the addition of pure water is completed, the mixture is further stirred for 1 hour, then filtered and dried, and copper powder coated with an Al compound as the metal compound used for the dielectric (or copper powder coated with the Al compound) )
［実施例２１］
実施例１６で得られた銅粒子１０ｇとイソプロピルアルコール１００ｇとを２００ｍＬビーカー中で十分に攪拌して混合した溶液に、チタニウムエチルアセトアセテート（三菱ガス化学株式会社製のＴＥＡＡ）０．５ｇを添加して、１時間攪拌した後、攪拌を継続しながら純水５ｇを１０分間で添加した。純水の添加が終了した後、さらに１時間攪拌し、ろ過、乾燥して、誘電体に使用される金属化合物としてＴｉ化合物が被着した銅粉（またはＴｉ化合物で被覆された銅粉）を得た。
[Example 21]
To a solution obtained by sufficiently stirring and mixing 10 g of the copper particles obtained in Example 16 and 100 g of isopropyl alcohol in a 200 mL beaker, 0.5 g of titanium ethyl acetoacetate (TEAA manufactured by Mitsubishi Gas Chemical Co., Ltd.) was added. After stirring for 1 hour, 5 g of pure water was added over 10 minutes while continuing stirring. After the addition of pure water is completed, the mixture is further stirred for 1 hour, filtered and dried, and a copper powder (or a copper powder coated with the Ti compound) coated with a Ti compound as a metal compound used for the dielectric is applied. Obtained.
［実施例２２］
実施例１６で得られた銅粒子１０ｇとイソプロピルアルコール１００ｇとを２００ｍＬビーカー中で十分に攪拌して混合した溶液に、チタン（ＩＶ）テトライソプロポキシド（和光純薬工業株式会社製）０．６４ｇとバリウムメトキシド溶液（金属バリウムをメタノールに溶かしてＢａ濃度０．０００７５モル／ｇに調整した溶液）２．９ｇの混合溶液を添加して、１時間攪拌した後、攪拌を継続しながら純水５ｇを１０分間で添加した。純水の添加が終了した後、さらに１時間攪拌し、ろ過、乾燥して、誘電体に使用される金属化合物としてＢａ−Ｔｉ化合物が被着した銅粉（またはＢａ−Ｔｉ化合物で被覆された銅粉）を得た。
[Example 22]
To a solution obtained by sufficiently stirring and mixing 10 g of the copper particles obtained in Example 16 and 100 g of isopropyl alcohol in a 200 mL beaker, 0.64 g of titanium (IV) tetraisopropoxide (manufactured by Wako Pure Chemical Industries, Ltd.) And a barium methoxide solution (a solution in which metal barium is dissolved in methanol and adjusted to a Ba concentration of 0.00075 mol / g) is added to a mixed solution of 2.9 g and stirred for 1 hour. 5 g was added over 10 minutes. After the addition of pure water was completed, the mixture was further stirred for 1 hour, filtered and dried, and coated with a copper powder (or a Ba-Ti compound) coated with a Ba-Ti compound as a metal compound used for the dielectric. Copper powder) was obtained.
［実施例２３］
実施例１６で得られた銅粒子１０ｇとイソプロピルアルコール１００ｇとを２００ｍＬビーカー中で十分に攪拌して混合した溶液に、テトラエトキシシラン（コルコート株式会社製のエチルシリケート２８）０．６２ｇを添加して、５分間攪拌した後、２８％アンモニア水（和光純薬工業株式会社製）１．３ｇを４５分間で添加した。アンモニア水の添加が終了した後、さらに１時間攪拌し、ろ過、乾燥して、誘電体に使用される金属化合物としてＳｉ化合物が被着した銅粉（またはてＳｉ化合物で被覆された銅粉）を得た。
[Example 23]
To a solution in which 10 g of the copper particles obtained in Example 16 and 100 g of isopropyl alcohol were sufficiently stirred and mixed in a 200 mL beaker, 0.62 g of tetraethoxysilane (ethyl silicate 28 manufactured by Colcoat Co., Ltd.) was added. After stirring for 5 minutes, 1.3 g of 28% ammonia water (manufactured by Wako Pure Chemical Industries, Ltd.) was added over 45 minutes. After the addition of ammonia water is complete, the mixture is further stirred for 1 hour, filtered and dried, and copper powder coated with a Si compound as a metal compound used for the dielectric (or copper powder coated with the Si compound) Got.
［比較例１］
反応促進剤を添加しなかった以外は、実施例１と同様の方法により、２価の銅イオンの還元反応を行った。この比較例では、銅までの還元が５分間で終了しなかったので、反応を中止した。
[Comparative Example 1]
A divalent copper ion reduction reaction was performed in the same manner as in Example 1 except that no reaction accelerator was added. In this comparative example, since the reduction to copper did not end in 5 minutes, the reaction was stopped.
［比較例２］
反応促進剤を添加せず、Ｌ−アスコルビン酸の量を２６４ｇにした以外は、実施例１と同様の方法により、２価の銅イオンの還元反応を行った。この比較例では、５分間の熟成で銅まで還元することができたが、実施例１と比べて銅への還元に時間がかかった。
[Comparative Example 2]
A divalent copper ion reduction reaction was carried out in the same manner as in Example 1 except that no reaction accelerator was added and the amount of L-ascorbic acid was changed to 264 g. In this comparative example, copper could be reduced by aging for 5 minutes, but it took longer to reduce to copper than in Example 1.
［比較例３］
反応促進剤として硝酸パラジウム（ＩＩ）０．０１０ｇを還元剤溶液ではなく２価の銅イオンを含む水溶液に溶解させた以外は、実施例１と同様の方法により、２価の銅イオンの還元反応を行って、銅粒子を得た。なお、この比較例では、添加した反応促進剤中のＰｄ量はＣｕに対して約５００ｐｐｍである。
[Comparative Example 3]
Reduction reaction of divalent copper ions by the same method as in Example 1 except that 0.010 g of palladium nitrate (II) was dissolved in an aqueous solution containing divalent copper ions instead of a reducing agent solution as a reaction accelerator. To obtain copper particles. In this comparative example, the amount of Pd in the added reaction accelerator is about 500 ppm with respect to Cu.
［比較例４］
反応促進剤として硝酸銀０．０７５ｇを２価の銅イオンを含む水溶液に溶解させた以外は、実施例１と同様の方法により、２価の銅イオンの還元反応を行って、銅粒子を得た。なお、この比較例では、添加した反応促進剤中のＡｇ量はＣｕに対して約５０００ｐｐｍである。
[Comparative Example 4]
Divalent copper ions were reduced by the same method as in Example 1 except that 0.075 g of silver nitrate was dissolved in an aqueous solution containing divalent copper ions as a reaction accelerator to obtain copper particles. . In this comparative example, the amount of Ag in the added reaction accelerator is about 5000 ppm with respect to Cu.
［比較例５］
保護剤としてのヘプタン酸の存在下で硝酸銀をヒドラジンで還元することによって作製したナノＡｇ粒子を反応促進剤として使用し、この反応促進剤を界面活性剤とともに水に分散させて使用した以外は、実施例１と同様の方法により、２価の銅イオンの還元反応を行って、銅粒子を得た。なお、この比較例では、添加した反応促進剤中のＡｇ量はＣｕに対して５００ｐｐｍである。また、使用したＡｇ粒子をＴＥＭ観察したところ、平均粒径２３ｎｍであった。
[Comparative Example 5]
Except for using nano Ag particles prepared by reducing silver nitrate with hydrazine in the presence of heptanoic acid as a protective agent as a reaction accelerator, and using this reaction accelerator dispersed in water together with a surfactant, By the same method as in Example 1, a divalent copper ion reduction reaction was performed to obtain copper particles. In this comparative example, the Ag amount in the added reaction accelerator is 500 ppm with respect to Cu. Further, when the Ag particles used were observed by TEM, the average particle size was 23 nm.
［比較例６］
反応促進剤を作製する際に凝集防止剤としてポリエチレンイミンを添加しなかった以外は、実施例１６と同様の方法により、２価の銅イオンの還元反応を行って、銅粒子を得た。この比較例では、還元反応により反応促進剤（Ａｇ粒子）を得た後に攪拌を継続することにより、生成したＡｇ粒子が凝集していくのを目視により確認することができた。
[Comparative Example 6]
A divalent copper ion reduction reaction was carried out in the same manner as in Example 16 except that polyethyleneimine was not added as an aggregation inhibitor when preparing the reaction accelerator to obtain copper particles. In this comparative example, it was confirmed by visual observation that the produced Ag particles were aggregated by continuing the stirring after obtaining the reaction accelerator (Ag particles) by the reduction reaction.
［比較例７］
還元剤溶液に水酸化ナトリウム溶液（５０％）を添加してｐＨを７に調整した以外は、実施例１と同様の方法により、２価の銅イオンの還元反応を行って、銅粒子を得た。なお、この比較例では、還元剤溶液を２価の銅イオンを含む水溶液（硫酸銅溶液）添加したときに、硫酸銅溶液がオレンジ色に変化したため、亜酸化銅が生成していたと予想される。また、銅までの還元が遅かったため、反応時間（熟成時間）を実施例１よりも５分長くして１０分間とした。
[Comparative Example 7]
Divalent copper ions were reduced by the same method as in Example 1 except that a sodium hydroxide solution (50%) was added to the reducing agent solution to adjust the pH to 7, thereby obtaining copper particles. It was. In addition, in this comparative example, when the reducing agent solution was added with an aqueous solution (copper sulfate solution) containing divalent copper ions, the copper sulfate solution was changed to orange, so that it was expected that cuprous oxide was generated. . Further, since the reduction to copper was slow, the reaction time (ripening time) was made 5 minutes longer than Example 1 to 10 minutes.
［比較例８］
硫酸銅を水酸化ナトリウムで中和して得られた水酸化銅溶液にブドウ糖を添加して作製した亜酸化銅をろ過し、洗浄し、乾燥し、１０．７３ｇを計量して、純水３４１０ｇに再分散させて作製した亜酸化銅溶液を２価の銅イオンを含む水溶液の代わりに使用し、２Ｌビーカーに入れた純水６００ｇに還元剤としてヒドラジン水和物５．８５ｇを添加して均一に混合させた還元剤溶液を使用した以外は、実施例１と同様の方法により、銅イオンの還元反応を行って、銅粒子を得た。なお、この比較例では、銅までの還元が終了までに７時間程度かかった。
[Comparative Example 8]
Cuprous oxide prepared by adding glucose to copper hydroxide solution obtained by neutralizing copper sulfate with sodium hydroxide was filtered, washed, dried, weighed 10.73 g, and 3410 g of pure water A cuprous oxide solution prepared by re-dispersing in water was used instead of an aqueous solution containing divalent copper ions, and 5.85 g of hydrazine hydrate as a reducing agent was added to 600 g of pure water placed in a 2 L beaker to make it uniform. A copper ion reduction reaction was performed in the same manner as in Example 1 except that the reducing agent solution mixed in the above was used to obtain copper particles. In this comparative example, it took about 7 hours to complete the reduction to copper.
［比較例９］
２Ｌビーカーに入れた純水６００ｇに還元剤としてヒドラジン水和物２３．５ｇを添加して均一に混合させた還元剤溶液を使用した以外は、比較例８と同様の方法により、２価の銅イオンの還元反応を行って、銅粒子を得た。なお、この比較例では、銅までの還元が終了までに３時間程度かかった。
[Comparative Example 9]
A divalent copper was prepared in the same manner as in Comparative Example 8 except that a reducing agent solution in which 23.5 g of hydrazine hydrate was added as a reducing agent to 600 g of pure water placed in a 2 L beaker and mixed uniformly was used. An ion reduction reaction was performed to obtain copper particles. In this comparative example, it took about 3 hours to complete the reduction to copper.
［比較例１０］
Ｌ−アスコルビン酸の代わりに５０％次亜リン酸溶液（和光純薬工業株式会社製）３９．６ｇを使用した以外は、実施例１と同様の方法により、２価の銅イオンの還元反応を行って、銅粒子を得た。
[Comparative Example 10]
A divalent copper ion reduction reaction was carried out in the same manner as in Example 1 except that 39.6 g of a 50% hypophosphorous acid solution (manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of L-ascorbic acid. Going to obtain copper particles.
［比較例１１］
硫酸銅５水和物の代わりに硝酸銅３水和物３６．２ｇを使用し、Ｌ−アスコルビン酸の代わりに次亜リン酸ナトリウム１水和物（和光純薬工業株式会社製）３８．４ｇを使用した以外は、実施例１と同様の方法により、２価の銅イオンの還元反応を行った。この比較例では、銅までの還元が進まなかったため、２０分間攪拌を継続したが、それでも還元反応が起こらなかったので中止した。
[Comparative Example 11]
Instead of copper sulfate pentahydrate, 36.2 g of copper nitrate trihydrate was used, and sodium hypophosphite monohydrate (manufactured by Wako Pure Chemical Industries, Ltd.) 38.4 g instead of L-ascorbic acid A divalent copper ion reduction reaction was performed in the same manner as in Example 1 except that was used. In this comparative example, since the reduction to copper did not proceed, the stirring was continued for 20 minutes.
［比較例１２］
還元剤溶液および２価の銅イオンを含む水溶液を作製する際の温度をそれぞれ８０℃にした以外は、比較例１１と同様の方法により、２価の銅イオンの還元反応を行った。この比較例では、５分間では銅までの還元が進まなかったため、攪拌を継続したところ、還元剤溶液の投入から約１５分後に急激な反応が起こり、銅粒子を得ることができた。
[Comparative Example 12]
A divalent copper ion reduction reaction was performed in the same manner as in Comparative Example 11 except that the temperature at the time of preparing the reducing agent solution and the aqueous solution containing the divalent copper ion was 80 ° C., respectively. In this comparative example, since the reduction to copper did not proceed in 5 minutes, when stirring was continued, a rapid reaction occurred approximately 15 minutes after the introduction of the reducing agent solution, and copper particles could be obtained.
［比較例１３］
Ｌ−アスコルビン酸の還元剤溶液の代わりに、ヒドラジン水和物１１．８ｇを純水６００ｇに溶解した溶液を希硫酸でｐＨ３に調整した還元剤溶液を使用し、反応促進剤を還元剤溶液ではなく２価の銅イオンを含む水溶液に添加した以外は、実施例１と同様の方法により、銅粒子を得た。この比較例では、銅までの還元時間は、実施例１ほど速くはないが、５分以内に銅まで還元することができた。
[Comparative Example 13]
Instead of the reducing agent solution of L-ascorbic acid, a reducing agent solution in which 11.8 g of hydrazine hydrate was dissolved in 600 g of pure water was adjusted to pH 3 with dilute sulfuric acid, and the reaction accelerator was used as the reducing agent solution. The copper particles were obtained by the same method as in Example 1 except that it was added to an aqueous solution containing divalent copper ions. In this comparative example, the reduction time to copper was not as fast as Example 1, but could be reduced to copper within 5 minutes.
［比較例１４］
Ｌ−アスコルビン酸の還元剤溶液の代わりに、水素化ホウ素ナトリウム３．６ｇを純水６００ｇに溶解した溶液を希硫酸でｐＨ３．５に調整した還元剤溶液を使用し、反応促進剤を還元剤溶液ではなく２価の銅イオンを含む水溶液に添加した以外は、実施例１と同様の方法により、銅粒子を得た。なお、希硫酸を添加した際にかなり激しい発泡が起こった。この比較例では、還元剤溶液を添加した直後から、色などの変化が見られなかったため、５分後に上記の還元剤溶液と同量の還元剤溶液（ｐＨ調整した溶液）を添加することによって、銅まで還元することができた。また、熟成時間は、初めの還元剤溶液の添加から１０分間であった。
[Comparative Example 14]
Instead of the reducing agent solution of L-ascorbic acid, a reducing agent solution prepared by adjusting 3.6 g of sodium borohydride in 600 g of pure water to pH 3.5 with dilute sulfuric acid was used, and the reaction accelerator was the reducing agent. Copper particles were obtained by the same method as in Example 1, except that the solution was added to an aqueous solution containing divalent copper ions instead of a solution. When dilute sulfuric acid was added, quite severe foaming occurred. In this comparative example, since no change in color or the like was observed immediately after the addition of the reducing agent solution, the same amount of reducing agent solution (pH adjusted solution) as the above reducing agent solution was added after 5 minutes. It was possible to reduce to copper. The aging time was 10 minutes from the first addition of the reducing agent solution.
また、実施例および比較例で得られた銅粉の粒度分布、５０％粒径（Ｄ５０）、Ｄｍｉｎ（検出の最小粒径）およびＤｍａｘ（検出の最大粒径）を、レーザー回折式粒度分布測定装置（ベックマン・コールター社製のＬＳ−２３０）を用いて測定した。これらの結果を表１〜表４に示す。なお、測定試料として、実施例および比較例で得られた銅粉と２−プロパノールをビーカーに入れて超音波分散槽などにより十分に分散させた液を使用した。 In addition, the particle size distribution, 50% particle size (D 50 ), D min (minimum particle size of detection) and D max (maximum particle size of detection) of the copper powder obtained in Examples and Comparative Examples were determined by laser diffraction. It measured using the particle size distribution analyzer (LS-230 by Beckman Coulter, Inc.). These results are shown in Tables 1 to 4. In addition, the liquid which put the copper powder and 2-propanol obtained by the Example and the comparative example in a beaker, and was fully disperse | distributed with the ultrasonic dispersion tank etc. was used as a measurement sample.
また、実施例および比較例で得られた銅粉の粒子形状および平均粒径を電界放出形走査電子顕微鏡（ＳＥＭ）（日立製作所製のＳ−４７００形）により評価した。なお、ＳＥＭによって観測した銅単体粒子の平均粒径（単体粒子径）は、粒子５０個のフェレ径の平均値から算出した。また、５万倍の撮影視野を用いて粒子径を算出したが、５０個の粒子数を測定できない場合には倍率を下げて撮影した視野を用いて粒子径を算出した。また、ＳＥＭによって測定された銅単体粒子の平均粒径に対する、レーザー回折式粒度分布測定装置によって測定された５０％粒径（Ｄ５０）の比を算出した。さらに、ＳＥＭによって観測した５０個の銅粒子から単一の略球状の銅粒子（凝結または結合している連晶粒子）の個数および割合を求めた。この結果を表５および表６に示す。 Moreover, the particle shape and average particle diameter of the copper powder obtained in Examples and Comparative Examples were evaluated by a field emission scanning electron microscope (SEM) (S-4700, manufactured by Hitachi, Ltd.). In addition, the average particle diameter (single particle diameter) of the copper single particle observed by SEM was calculated from the average value of the ferret diameters of 50 particles. Moreover, although the particle diameter was calculated using the imaging | photography visual field of 50,000 times, when the number of 50 particles was not measurable, the particle diameter was calculated using the visual field image | photographed by reducing magnification. Further, the ratio of the 50% particle size (D 50 ) measured by the laser diffraction particle size distribution measuring device to the average particle size of the single copper particles measured by SEM was calculated. Furthermore, the number and ratio of single substantially spherical copper particles (consolidated or bonded intergranular particles) were determined from 50 copper particles observed by SEM. The results are shown in Tables 5 and 6.
また、銅粒子中のＡｇまたはＰｄの含有量をＩＣＰ（日本ジャーレル・アッシュ社製のＩＲＩＳ／ＩＲＩＳ−ＡＰ）により測定した。この結果を表５および表６に示す。なお、実施例２０〜２２において、銅粒子に被着（または銅粒子を被覆）しているＡｌ、Ｔｉ、Ｂａの量を同様にＩＣＰにより測定したところ、実施例２０ではＡｌが０．４７質量％、実施例２１ではＴｉが０．５２質量％、実施例２２ではＴｉが１．０１質量％、Ｂａが２．８６質量％であった。また、実施例２３において、銅粒子に被着（または銅粒子を被覆）しているＳｉの量をＪＩＳ Ｈ１０６１に準拠して測定したところ、０．７２質量％であった。 Further, the content of Ag or Pd in the copper particles was measured by ICP (IRIS / IRIS-AP manufactured by Nippon Jarrell-Ash). The results are shown in Tables 5 and 6. In Examples 20 to 22, when the amounts of Al, Ti, and Ba deposited on copper particles (or coated with copper particles) were similarly measured by ICP, in Example 20, Al was 0.47 mass. %, In Example 21, Ti was 0.52% by mass, in Example 22, Ti was 1.01% by mass, and Ba was 2.86% by mass. In Example 23, when the amount of Si deposited on copper particles (or coated with copper particles) was measured in accordance with JIS H1061, it was 0.72% by mass.
表５および表６の結果から、実施例のように、２価の銅イオンを含む水溶液に還元剤を添加して銅粒子を還元析出させる銅粉の製造方法において、２価の銅イオンを含む水溶液および還元剤の少なくとも一方に、凝集防止剤を含む反応促進剤を存在させることにより、単分散した微粒子で、粒度分布がシャープで、粗粒を含まず、形状が真球に近いなどの特性を有する銅微粒子を安定して製造することができることがわかる。 From the results of Tables 5 and 6, as in the examples, in the method for producing copper powder in which a reducing agent is added to an aqueous solution containing divalent copper ions to reduce and precipitate copper particles, divalent copper ions are contained. By having a reaction accelerator containing an anti-aggregation agent in at least one of the aqueous solution and reducing agent, the characteristics are monodispersed fine particles, sharp particle size distribution, no coarse particles, and a shape close to a true sphere. It can be seen that the copper fine particles having the can be produced stably.
本発明による導電性ペースト用銅粉は、積層セラミックコンデンサや積層セラミックインダクタなどの積層セラミック電子部品の内部電極や、小型積層セラミックコンデンサや積層セラミックインダクタなどの外部電極を形成するための導電性ペーストに使用することができる。 The copper powder for conductive paste according to the present invention is used as a conductive paste for forming internal electrodes of multilayer ceramic electronic components such as multilayer ceramic capacitors and multilayer ceramic inductors, and external electrodes such as small multilayer ceramic capacitors and multilayer ceramic inductors. Can be used.
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| JP2012126815A (en) * | 2010-12-15 | 2012-07-05 | Tosoh Corp | Conductive ink composition, and method for producing the same |
| KR101276595B1 (en) * | 2011-01-10 | 2013-06-19 | 한국지질자원연구원 | APPARATUS FOR MANUFACTURING FINE Cu POWDERS USING WET CHEMICAL REDUCTION AND METHOD OF MANUFACTURING CUPPER POWDERS USING THE APPARATUS |
| EP2923781A4 (en) * | 2012-11-26 | 2016-07-13 | Mitsui Mining & Smelting Co | Copper powder and method for producing same |
| CN105050757B (en) * | 2013-04-05 | 2018-04-13 | 株式会社村田制作所 | Metal dust and its manufacture method, conductive paste and monolithic ceramic electronic component using the metal dust |
| KR101671324B1 (en) * | 2014-02-14 | 2016-11-02 | 미쓰이금속광업주식회사 | Copper powder |
| US20180029121A1 (en) * | 2015-02-27 | 2018-02-01 | Hitachi Chemical Company, Ltd. | Copper-containing particles, conductor-forming composition, method of producing conductior, conductor, and apparatus |
| JP6627228B2 (en) * | 2015-02-27 | 2020-01-08 | 日立化成株式会社 | Copper-containing particles, conductor-forming composition, method for producing conductor, conductor and device |
| WO2016152214A1 (en) * | 2015-03-26 | 2016-09-29 | 三井金属鉱業株式会社 | Copper powder and conductive composition containing same |
| JP2017204371A (en) * | 2016-05-11 | 2017-11-16 | 日立化成株式会社 | Conductor-forming composition, method for producing conductor, method for producing plating layer, conductor, laminate, and device |
| US10851257B2 (en) * | 2017-11-08 | 2020-12-01 | Eastman Kodak Company | Silver and copper nanoparticle composites |
| WO2019131378A1 (en) * | 2017-12-28 | 2019-07-04 | 株式会社Adeka | Copper powder manufacturing method, copper powder obtained using said manufacturing method, resin composition containing said copper powder, method for forming cured product of said resin composition, and said cured product |
| CN108372311B (en) * | 2018-03-21 | 2019-07-16 | 北京科技大学 | A method of copper nano-particle is prepared using modification of polysaccharides |
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