JP6746094B2 - Method for producing hydrophilic polymer-coated copper nanoparticles - Google Patents
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- 239000010949 copper Substances 0.000 title claims description 160
- 229910052802 copper Inorganic materials 0.000 title claims description 156
- 239000002105 nanoparticle Substances 0.000 title claims description 156
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 title claims description 153
- 229920001477 hydrophilic polymer Polymers 0.000 title claims description 98
- 238000004519 manufacturing process Methods 0.000 title claims description 32
- 239000002245 particle Substances 0.000 claims description 80
- 239000002904 solvent Substances 0.000 claims description 38
- 238000009835 boiling Methods 0.000 claims description 28
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 24
- 229940116318 copper carbonate Drugs 0.000 claims description 24
- GEZOTWYUIKXWOA-UHFFFAOYSA-L copper;carbonate Chemical compound [Cu+2].[O-]C([O-])=O GEZOTWYUIKXWOA-UHFFFAOYSA-L 0.000 claims description 24
- 239000011247 coating layer Substances 0.000 claims description 23
- 229920000036 polyvinylpyrrolidone Polymers 0.000 claims description 22
- 239000001267 polyvinylpyrrolidone Substances 0.000 claims description 22
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 claims description 22
- 150000001879 copper Chemical class 0.000 claims description 21
- ZIBGPFATKBEMQZ-UHFFFAOYSA-N triethylene glycol Chemical compound OCCOCCOCCO ZIBGPFATKBEMQZ-UHFFFAOYSA-N 0.000 claims description 20
- -1 diol monoalkyl ether Chemical class 0.000 claims description 18
- 238000010438 heat treatment Methods 0.000 claims description 16
- 150000002009 diols Chemical class 0.000 claims description 10
- 229920001223 polyethylene glycol Polymers 0.000 claims description 8
- 230000001476 alcoholic effect Effects 0.000 claims description 7
- JJLJMEJHUUYSSY-UHFFFAOYSA-L Copper hydroxide Chemical compound [OH-].[OH-].[Cu+2] JJLJMEJHUUYSSY-UHFFFAOYSA-L 0.000 claims description 6
- 239000005750 Copper hydroxide Substances 0.000 claims description 6
- UWHCKJMYHZGTIT-UHFFFAOYSA-N Tetraethylene glycol, Natural products OCCOCCOCCOCCO UWHCKJMYHZGTIT-UHFFFAOYSA-N 0.000 claims description 6
- 229910001956 copper hydroxide Inorganic materials 0.000 claims description 6
- 150000001346 alkyl aryl ethers Chemical class 0.000 claims description 4
- 239000011261 inert gas Substances 0.000 claims description 4
- 239000002184 metal Substances 0.000 claims description 4
- 229910052751 metal Inorganic materials 0.000 claims description 4
- 239000002202 Polyethylene glycol Substances 0.000 claims description 3
- 229920002873 Polyethylenimine Polymers 0.000 claims description 3
- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 3
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 3
- 150000002334 glycols Chemical class 0.000 claims description 2
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 48
- 239000010419 fine particle Substances 0.000 description 36
- 230000000052 comparative effect Effects 0.000 description 23
- 230000000844 anti-bacterial effect Effects 0.000 description 21
- 238000009826 distribution Methods 0.000 description 20
- 238000000034 method Methods 0.000 description 17
- JPVYNHNXODAKFH-UHFFFAOYSA-N Cu2+ Chemical compound [Cu+2] JPVYNHNXODAKFH-UHFFFAOYSA-N 0.000 description 16
- 229910001431 copper ion Inorganic materials 0.000 description 16
- 239000003638 chemical reducing agent Substances 0.000 description 15
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 15
- 239000000243 solution Substances 0.000 description 12
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 description 11
- 238000006722 reduction reaction Methods 0.000 description 9
- 239000000084 colloidal system Substances 0.000 description 7
- 239000000463 material Substances 0.000 description 7
- 239000007864 aqueous solution Substances 0.000 description 6
- 239000002082 metal nanoparticle Substances 0.000 description 6
- 241000588724 Escherichia coli Species 0.000 description 5
- 239000003125 aqueous solvent Substances 0.000 description 5
- 239000011258 core-shell material Substances 0.000 description 5
- 230000001954 sterilising effect Effects 0.000 description 5
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 4
- OAKJQQAXSVQMHS-UHFFFAOYSA-N Hydrazine Chemical compound NN OAKJQQAXSVQMHS-UHFFFAOYSA-N 0.000 description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- 238000000026 X-ray photoelectron spectrum Methods 0.000 description 4
- 238000000635 electron micrograph Methods 0.000 description 4
- 239000012488 sample solution Substances 0.000 description 4
- SDVHRXOTTYYKRY-UHFFFAOYSA-J tetrasodium;dioxido-oxo-phosphonato-$l^{5}-phosphane Chemical compound [Na+].[Na+].[Na+].[Na+].[O-]P([O-])(=O)P([O-])([O-])=O SDVHRXOTTYYKRY-UHFFFAOYSA-J 0.000 description 4
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 3
- 239000006142 Luria-Bertani Agar Substances 0.000 description 3
- XSTXAVWGXDQKEL-UHFFFAOYSA-N Trichloroethylene Chemical compound ClC=C(Cl)Cl XSTXAVWGXDQKEL-UHFFFAOYSA-N 0.000 description 3
- 239000005456 alcohol based solvent Substances 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 description 3
- 239000010410 layer Substances 0.000 description 3
- 238000001228 spectrum Methods 0.000 description 3
- YIWGJFPJRAEKMK-UHFFFAOYSA-N 1-(2H-benzotriazol-5-yl)-3-methyl-8-[2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carbonyl]-1,3,8-triazaspiro[4.5]decane-2,4-dione Chemical compound CN1C(=O)N(c2ccc3n[nH]nc3c2)C2(CCN(CC2)C(=O)c2cnc(NCc3cccc(OC(F)(F)F)c3)nc2)C1=O YIWGJFPJRAEKMK-UHFFFAOYSA-N 0.000 description 2
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 2
- 238000004220 aggregation Methods 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 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 2
- 235000014113 dietary fatty acids Nutrition 0.000 description 2
- ZBCBWPMODOFKDW-UHFFFAOYSA-N diethanolamine Chemical compound OCCNCCO ZBCBWPMODOFKDW-UHFFFAOYSA-N 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- 239000002270 dispersing agent Substances 0.000 description 2
- 239000000194 fatty acid Substances 0.000 description 2
- 229930195729 fatty acid Natural products 0.000 description 2
- 150000004665 fatty acids Chemical class 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 235000011187 glycerol Nutrition 0.000 description 2
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 2
- 239000002609 medium Substances 0.000 description 2
- 239000002504 physiological saline solution Substances 0.000 description 2
- 239000002798 polar solvent Substances 0.000 description 2
- 229920005862 polyol Polymers 0.000 description 2
- 150000003077 polyols Chemical class 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 239000000523 sample Substances 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- 239000012279 sodium borohydride Substances 0.000 description 2
- 229910000033 sodium borohydride Inorganic materials 0.000 description 2
- JLGLQAWTXXGVEM-UHFFFAOYSA-N triethylene glycol monomethyl ether Chemical compound COCCOCCOCCO JLGLQAWTXXGVEM-UHFFFAOYSA-N 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- COBPKKZHLDDMTB-UHFFFAOYSA-N 2-[2-(2-butoxyethoxy)ethoxy]ethanol Chemical compound CCCCOCCOCCOCCO COBPKKZHLDDMTB-UHFFFAOYSA-N 0.000 description 1
- WFSMVVDJSNMRAR-UHFFFAOYSA-N 2-[2-(2-ethoxyethoxy)ethoxy]ethanol Chemical compound CCOCCOCCOCCO WFSMVVDJSNMRAR-UHFFFAOYSA-N 0.000 description 1
- 241000894006 Bacteria Species 0.000 description 1
- BBEPMKOCUYLIFM-UHFFFAOYSA-N COCCOCCOCCO.C=C.C=C.C=C Chemical compound COCCOCCOCCO.C=C.C=C.C=C BBEPMKOCUYLIFM-UHFFFAOYSA-N 0.000 description 1
- 239000012691 Cu precursor Substances 0.000 description 1
- 241000233866 Fungi Species 0.000 description 1
- 238000004833 X-ray photoelectron spectroscopy Methods 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 238000000889 atomisation Methods 0.000 description 1
- 230000001580 bacterial effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000013068 control sample Substances 0.000 description 1
- 229910000365 copper sulfate Inorganic materials 0.000 description 1
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 1
- 150000001983 dialkylethers Chemical class 0.000 description 1
- 229940028356 diethylene glycol monobutyl ether Drugs 0.000 description 1
- XXJWXESWEXIICW-UHFFFAOYSA-N diethylene glycol monoethyl ether Chemical compound CCOCCOCCO XXJWXESWEXIICW-UHFFFAOYSA-N 0.000 description 1
- 229940075557 diethylene glycol monoethyl ether Drugs 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000005661 hydrophobic surface Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 239000002923 metal particle Substances 0.000 description 1
- 239000011859 microparticle Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- JCGNDDUYTRNOFT-UHFFFAOYSA-N oxolane-2,4-dione Chemical compound O=C1COC(=O)C1 JCGNDDUYTRNOFT-UHFFFAOYSA-N 0.000 description 1
- JLFNLZLINWHATN-UHFFFAOYSA-N pentaethylene glycol Chemical compound OCCOCCOCCOCCOCCO JLFNLZLINWHATN-UHFFFAOYSA-N 0.000 description 1
- 239000002861 polymer material Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- YFNKIDBQEZZDLK-UHFFFAOYSA-N triglyme Chemical compound COCCOCCOCCOC YFNKIDBQEZZDLK-UHFFFAOYSA-N 0.000 description 1
- 229920003169 water-soluble polymer Polymers 0.000 description 1
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- Agricultural Chemicals And Associated Chemicals (AREA)
- Manufacture Of Metal Powder And Suspensions Thereof (AREA)
- Powder Metallurgy (AREA)
Description
本発明は、親水性ポリマー被覆銅ナノ粒子、その製造方法、及び殺菌材料に関する。 The present invention relates to hydrophilic polymer-coated copper nanoparticles, a method for producing the same, and a sterilizing material.
平均粒子径が１００ｎｍ以下の金属ナノ粒子は、一般的な大きさの金属粒子とは異なる特性を有することが知られており、この特性を活かした用途が様々な分野において検討されている。 It is known that metal nanoparticles having an average particle size of 100 nm or less have characteristics different from those of metal particles having a general size, and applications utilizing these characteristics have been studied in various fields.
このような金属ナノ粒子の製造方法として、例えば、国際公開２００４／０１２８８４号（特許文献１）には、不活性ガス雰囲気中においてアミン化合物の存在下で金属塩を含む出発物質に熱処理を施すことにより、金属ナノ粒子を製造する方法が開示されている。また、特開２０１２−４６７７９号公報（特許文献２）には、アルコール溶媒中、特定の脂肪酸と特定の脂肪族アミンとの共存下で、アルコール系溶媒に不溶な金属塩を還元せしめることにより、表面が前記脂肪酸及び前記脂肪族アミンを含有する有機被膜で被覆された金属ナノ粒子を製造する方法が開示されている。しかしながら、これらの方法は製造条件が複雑であり、より簡便な製造方法が求められていた。また、アミン化合物を使用するため、製造環境に十分に注意する必要があった。さらに、得られる表面被覆金属ナノ粒子は表面が疎水性であるため、金属ナノ粒子を水に分散させる必要がある用途（例えば、殺菌材料）に使用することは困難であった。 As a method for producing such metal nanoparticles, for example, in WO 2004/012884 (Patent Document 1), a heat treatment is applied to a starting material containing a metal salt in the presence of an amine compound in an inert gas atmosphere. Discloses a method for producing metal nanoparticles. Further, in JP-A-2012-46779 (Patent Document 2), by reducing a metal salt insoluble in an alcohol solvent in the presence of a specific fatty acid and a specific aliphatic amine in an alcohol solvent, A method for producing metal nanoparticles whose surface is coated with an organic coating containing the fatty acid and the aliphatic amine is disclosed. However, these methods have complicated manufacturing conditions, and a simpler manufacturing method has been demanded. Moreover, since an amine compound is used, it is necessary to pay sufficient attention to the production environment. Furthermore, since the surface-coated metal nanoparticles obtained have a hydrophobic surface, it has been difficult to use the applications in which the metal nanoparticles need to be dispersed in water (for example, a sterilizing material).
また、特開２００８−１９５０３号公報（特許文献３）には、ソジウムハイポフォスフェート等の還元剤、ポリビニルピロリドン等の分散剤及びポリオール等の極性溶媒を含む第１溶液に、銅前駆体及びポリオール等の極性溶媒を含む第２溶液を一度に投入して混合することにより、銅ナノ粒子を製造する方法が開示されている。この方法では、分散剤としてポリビニルピロリドン等を用いているため、得られる銅ナノ粒子を水に分散させることが可能である。しかしながら、この方法で製造した銅ナノ粒子は、粒径分布が広く、ナノ粒子の特性を十分に発揮できないという問題があった。また、還元剤が不純物として残存するという問題もあった。 Further, JP-A 2008-19503 (Patent Document 3) discloses that a copper precursor and a first solution containing a reducing agent such as sodium hypophosphate, a dispersant such as polyvinylpyrrolidone, and a polar solvent such as a polyol are added. A method for producing copper nanoparticles by adding a second solution containing a polar solvent such as a polyol at once and mixing them is disclosed. In this method, since polyvinylpyrrolidone or the like is used as a dispersant, the obtained copper nanoparticles can be dispersed in water. However, there is a problem that the copper nanoparticles produced by this method have a wide particle size distribution and cannot fully exhibit the characteristics of the nanoparticles. There is also a problem that the reducing agent remains as an impurity.
さらに、Ｃｈｅｍ．Ｌｅｔｔ．、１９９３年、１６１１〜１６１４頁（非特許文献１）には、ＣｕＳＯ４・５Ｈ２Ｏ及びポリビニルピロリドンをグリコールに溶解し、ｐＨを９．５〜１０．５に調整した後、１９８℃で還流させることによって、ポリビニルピロリドンで被覆された銅ナノ粒子が得る方法が記載されている。この方法は、特許文献１及び２に記載の方法に比べて簡便であり、また、アミン化合物を使用しないため、環境にも優しく、さらに、得られる銅ナノ粒子は、ポリビニルピロリドンで被覆されているため、水に分散させることが可能である。しかしながら、この方法で製造した銅ナノ粒子は、粒径分布が広く、ナノ粒子の特性を十分に発揮できないという問題があった。 In addition, Chem. Lett. , 1993, pp. 1611 to 1614 (Non-patent document 1), CuSO 4 5H 2 O and polyvinylpyrrolidone were dissolved in glycol and the pH was adjusted to 9.5 to 10.5, and then refluxed at 198°C. The method for obtaining copper nanoparticles coated with polyvinylpyrrolidone is described. This method is simpler than the methods described in Patent Documents 1 and 2, and since it does not use an amine compound, it is environmentally friendly, and the obtained copper nanoparticles are coated with polyvinylpyrrolidone. Therefore, it can be dispersed in water. However, there is a problem that the copper nanoparticles produced by this method have a wide particle size distribution and cannot fully exhibit the characteristics of the nanoparticles.
一方、富山県工業技術センター研究報告、２０１０年、第２４号、２２〜２３頁（非特許文献２）には、銀系コア−シェル型ナノ構造体粒子の水溶液を高圧湿式ジェットミル法により粉砕・微粒化することによって、粒径が２００ｎｍ以下の銀系コア−シェルナノ粒子が得られることが記載されており、銅系コア−シェルナノ粒子についても同じ傾向を示すことが記載されている。また、これらのナノ粒子が各種細菌や黴に対する抗菌作用を有することも記載されている。しかしながら、銅系コア−シェルナノ粒子については、大腸菌の発育を阻止するために、水溶液中の濃度を１１３．１ｐｐｍ以上にする必要があり、低濃度の銅ナノ粒子水溶液では十分な殺菌作用を得ることは困難であった。 On the other hand, in Toyama Industrial Technology Center Research Report, 2010, No. 24, pp. 22-23 (Non-patent Document 2), an aqueous solution of silver-based core-shell type nanostructured particles is pulverized by a high pressure wet jet mill method. -It is described that by atomization, silver-based core-shell nanoparticles having a particle size of 200 nm or less can be obtained, and copper-based core-shell nanoparticles exhibit the same tendency. It is also described that these nanoparticles have an antibacterial action against various bacteria and fungi. However, for the copper-based core-shell nanoparticles, the concentration in the aqueous solution needs to be 113.1 ppm or more in order to prevent the growth of E. coli, and a sufficient concentration of bactericidal action can be obtained with a low-concentration aqueous solution of the copper nanoparticles. Was difficult.
本発明は、上記従来技術の有する課題に鑑みてなされたものであり、ソジウムハイポフォスフェート（ＮａＨ２ＰＯ２）、ヒドラジン（Ｎ２Ｈ４）、ハイドロクロライド（ＨＣｌ）、ソジウムボロハイドライド（ＮａＢＨ４）等の水素供与性還元剤を用いることなく、簡便な方法で得ることができ、粒径分布が狭く、水に分散させることが可能な銅ナノ粒子を提供することを目的とする。 The present invention has been made in view of the problems of the above-mentioned prior art, and includes sodium hypophosphate (NaH 2 PO 2 ), hydrazine (N 2 H 4 ), hydrochloride (HCl), and sodium borohydride ( An object of the present invention is to provide copper nanoparticles that can be obtained by a simple method without using a hydrogen-donating reducing agent such as NaBH 4 ), have a narrow particle size distribution, and can be dispersed in water.
本発明者らは、上記目的を達成すべく鋭意研究を重ねた結果、沸点が２００℃以上のジオール及び沸点が２００℃以上のジオールモノアルキルエーテルのうちの少なくとも１種のアルコール系溶媒中、親水性ポリマーの共存下で、炭酸銅及び水酸化銅のうちの少なくとも１種の銅塩に、２００〜３００℃の加熱処理を施すことによって、粒径分布が狭く、水に分散させることが可能な銅ナノ粒子が得られることを見出し、本発明を完成するに至った。 As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that the hydrophilic property of the diol having a boiling point of 200° C. or higher and the diol monoalkyl ether having a boiling point of 200° C. or higher in at least one alcohol solvent is hydrophilic. By subjecting at least one copper salt of copper carbonate and copper hydroxide to a heat treatment at 200 to 300° C. in the presence of a water-soluble polymer, the particle size distribution is narrow and the particles can be dispersed in water. The inventors have found that copper nanoparticles can be obtained, and completed the present invention.
すなわち、本発明の親水性ポリマー被覆銅ナノ粒子の製造方法は、沸点が２４８℃以上のジオール及び沸点が２４８℃以上のジオールモノアルキルエーテルからなる群から選択される少なくとも１種のアルコール系溶媒中、不活性ガス雰囲気下、親水性ポリマーの共存下で、炭酸銅及び水酸化銅からなる群から選択される少なくとも１種の銅塩に、２００〜３００℃で加熱処理を施すことにより、金属として銅のみを含有し、平均粒子径が１０〜１００ｎｍであり、粒子径の相対標準偏差が２６．５％以下である銅ナノ粒子を形成させ、かつ、該銅ナノ粒子の表面に前記親水性ポリマーからなる被覆層を形成させることを特徴とするものである。 That is, the production method of the hydrophilic polymer coated copper nanoparticles of the present invention, at least one alcoholic solvent having a boiling point diol and a boiling point above 248 ° C. is selected from the group consisting of a diol monoalkyl ether or 248 ° C. As a metal, by subjecting at least one copper salt selected from the group consisting of copper carbonate and copper hydroxide to heat treatment at 200 to 300° C. in an inert gas atmosphere in the presence of a hydrophilic polymer, Copper nanoparticles containing only copper, having an average particle diameter of 10 to 100 nm, and a relative standard deviation of particle diameter of 26.5 % or less are formed, and the hydrophilic polymer is formed on the surface of the copper nanoparticles. It is characterized in that a coating layer consisting of is formed.
本発明の親水性ポリマー被覆銅ナノ粒子の製造方法において、前記アルコール系溶媒としては、トリエチレングリコール、テトラエチレングリコール、及びこれらのグリコールのモノアルキルエーテルからなる群から選択される少なくとも１種が好ましく、沸点が２４８℃以上のジオールモノアルキルエーテルがより好ましく、トリエチレングリコールのモノアルキルエーテル及びテトラエチレングリコールのモノアルキルエーテルからなる群から選択される少なくとも１種が更に好ましい。また、前記親水性ポリマーとしては、ポリビニルピロリドン、ポリエチレングリコール、ポリビニルアルコール、及びポリエチレンイミンからなる群から選択される少なくとも１種が好ましい。 In the method for producing hydrophilic polymer-coated copper nanoparticles of the present invention, the alcohol solvent is preferably at least one selected from the group consisting of triethylene glycol, tetraethylene glycol, and monoalkyl ethers of these glycols. A diol monoalkyl ether having a boiling point of 248° C. or higher is more preferable, and at least one selected from the group consisting of triethylene glycol monoalkyl ether and tetraethylene glycol monoalkyl ether is further preferable . In addition, the hydrophilic polymer is preferably at least one selected from the group consisting of polyvinylpyrrolidone, polyethylene glycol, polyvinyl alcohol, and polyethyleneimine.
なお、本発明の製造方法によって粒径分布が狭い親水性ポリマー被覆銅ナノ粒子が得られる理由は必ずしも定かではないが、本発明者らは以下のように推察する。すなわち、本発明の親水性ポリマー銅ナノ粒子の製造方法においては、銅塩としてアルコール系溶媒に不溶又は難溶な炭酸銅又は水酸化銅を用いており、アルコール系溶媒に溶解している銅イオンは微量であるため、銅イオンの還元反応が遅くなり、粒子径が小さく、粒径分布が狭い銅ナノ粒子が得られると推察される。一方、非特許文献１に記載の方法では、銅塩としてグリコールに可溶な硫酸銅を用いており、グリコール中に多量の銅イオンが存在するため、銅ナノ粒子が生成しやすく、また、低温から銅イオンの還元反応が起こるため、初期に生成した銅ナノ粒子が１９８℃までの昇温過程において粒成長し、粒径分布が広い銅ナノ粒子が生成すると推察される。 The reason why the hydrophilic polymer-coated copper nanoparticles having a narrow particle size distribution can be obtained by the production method of the present invention is not always clear, but the present inventors presume as follows. That is, in the method for producing hydrophilic polymer copper nanoparticles of the present invention, copper carbonate or copper hydroxide that is insoluble or hardly soluble in an alcohol solvent is used as the copper salt, and copper ions dissolved in the alcohol solvent are used. It is presumed that since the amount of is very small, the reduction reaction of copper ions is slowed down, and copper nanoparticles having a small particle size and a narrow particle size distribution can be obtained. On the other hand, in the method described in Non-Patent Document 1, copper sulfate that is soluble in glycol is used as the copper salt, and since a large amount of copper ions are present in the glycol, copper nanoparticles are easily generated, and at low temperature. It is speculated that since the reduction reaction of copper ions occurs from the above, the copper nanoparticles initially formed grow during the temperature rising process up to 198° C. to form copper nanoparticles having a wide particle size distribution.
また、本発明の親水性ポリマー銅ナノ粒子の製造方法に用いられる溶媒は、沸点が２００℃以上であり、エチレングリコールに比べて長鎖のアルコールであるため、還元剤として作用する水酸基の濃度が低く、銅イオンの還元反応が遅くなり、粒子径が小さく、粒径分布が狭い銅ナノ粒子が得られると推察される。また、高温での加熱が可能となるため、銅イオンの還元反応を均一に進行させることができ、粒径分布が狭い銅ナノ粒子が得られると推察される。一方、エチレングリコールやトリオールを用いた場合には、還元剤として作用する水酸基の濃度が高く、銅イオンの還元反応が進行しやすいため、粒子径が大きく、粒径分布が広い銅ナノ粒子が生成すると推察される。また、水素供与性還元剤を用いた場合にも、銅イオンの還元反応が進行しやすいため、粒子径が大きく、粒径分布が広い銅ナノ粒子が生成すると推察される。 Further, since the solvent used in the method for producing hydrophilic polymer copper nanoparticles of the present invention has a boiling point of 200° C. or higher and is a long-chain alcohol compared to ethylene glycol, the concentration of the hydroxyl group acting as a reducing agent is high. It is presumed that copper nanoparticles having a low particle size, a low particle size, a small particle size and a narrow particle size distribution can be obtained. Moreover, since it becomes possible to heat at a high temperature, it is presumed that the reduction reaction of copper ions can proceed uniformly and copper nanoparticles having a narrow particle size distribution can be obtained. On the other hand, when ethylene glycol or triol is used, the concentration of hydroxyl groups that act as a reducing agent is high, and the reduction reaction of copper ions easily proceeds, so that copper nanoparticles with a large particle size and a wide particle size distribution are generated. Then it is speculated. Further, even when a hydrogen-donating reducing agent is used, the reduction reaction of copper ions is likely to proceed, and it is speculated that copper nanoparticles having a large particle size and a wide particle size distribution are generated.
また、本発明の親水性ポリマー銅ナノ粒子が優れた殺菌作用を示す理由は必ずしも定かではないが、本発明者らは以下のように推察する。すなわち、本発明の親水性ポリマー銅ナノ粒子は、平均粒子径が小さく、粒径分布が狭いため、ナノ粒子としての作用が十分に発揮され、低濃度の銅ナノ粒子溶液であっても優れた殺菌作用を示すと推察される。一方、非特許文献２に記載の銅系コア−シェルナノ粒子は、粒径分布が広いため、ナノ粒子としての作用が十分に発揮されず、低濃度の銅ナノ粒子溶液では十分な殺菌作用を示さないと推察される。 Further, the reason why the hydrophilic polymer copper nanoparticles of the present invention exhibit an excellent bactericidal action is not always clear, but the present inventors speculate as follows. That is, since the hydrophilic polymer copper nanoparticles of the present invention have a small average particle size and a narrow particle size distribution, the action as nanoparticles is sufficiently exhibited, and even a low-concentration copper nanoparticle solution is excellent. It is presumed that it has a bactericidal action. On the other hand, since the copper-based core-shell nanoparticles described in Non-Patent Document 2 have a wide particle size distribution, they do not sufficiently exhibit the action as nanoparticles, and show a sufficient bactericidal action in a low-concentration copper nanoparticle solution. It is guessed that there is no.
本発明によれば、水素供与性還元剤を用いることなく、粒径分布が狭く、水に分散させることが可能な銅ナノ粒子を簡便な方法で得ることが可能となる。 According to the present invention, copper nanoparticles having a narrow particle size distribution and capable of being dispersed in water can be obtained by a simple method without using a hydrogen-donating reducing agent.
以下、本発明をその好適な実施形態に即して詳細に説明する。 Hereinafter, the present invention will be described in detail with reference to its preferred embodiments.
＜親水性ポリマー被覆銅ナノ粒子の製造方法＞
先ず、本発明の親水性ポリマー被覆銅ナノ粒子の製造方法について説明する。本発明の親水性ポリマー被覆銅ナノ粒子の製造方法は、沸点が２００℃以上のジオール及び沸点が２００℃以上のジオールモノアルキルエーテルからなる群から選択される少なくとも１種のアルコール系溶媒中、不活性ガス雰囲気下、親水性ポリマーの共存下で、炭酸銅及び水酸化銅からなる群から選択される少なくとも１種の銅塩に、２００〜３００℃で加熱処理を施すことにより、平均粒子径が１０〜１００ｎｍであり、粒子径の相対標準偏差が３０％以下である銅ナノ粒子を形成させ、かつ、該銅ナノ粒子の表面に前記親水性ポリマーからなる被覆層を形成させる方法である。
<Method for producing hydrophilic polymer-coated copper nanoparticles>
First, the method for producing the hydrophilic polymer-coated copper nanoparticles of the present invention will be described. The method for producing copper nanoparticles coated with a hydrophilic polymer according to the present invention is carried out in at least one alcohol solvent selected from the group consisting of diols having a boiling point of 200° C. or higher and diol monoalkyl ethers having a boiling point of 200° C. or higher. By subjecting at least one copper salt selected from the group consisting of copper carbonate and copper hydroxide to a heat treatment at 200 to 300° C. in an active gas atmosphere in the presence of a hydrophilic polymer, the average particle diameter is It is a method of forming copper nanoparticles having a relative standard deviation of particle diameters of 10 to 100 nm and 30% or less, and forming a coating layer made of the hydrophilic polymer on the surfaces of the copper nanoparticles.
（アルコール系溶媒）
本発明の親水性ポリマー被覆銅ナノ粒子の製造方法においては、溶媒として、沸点が２００℃以上（好ましくは２２０℃以上、より好ましくは２３０℃以上）のジオール及び沸点が２００℃以上（好ましくは２２０℃以上、より好ましくは２３０℃以上）のジオールモノアルキルエーテルからなる群から選択される少なくとも１種のアルコール系溶媒を使用する。このようなアルコール系溶媒は、適度な速度で銅イオンの還元反応を進行させる還元剤として作用する。従って、本発明の親水性ポリマー被覆銅ナノ粒子の製造方法においては、ソジウムハイポフォスフェート（ＮａＨ２ＰＯ２）、ヒドラジン（Ｎ２Ｈ４）、ハイドロクロライド（ＨＣｌ）、ソジウムボロハイドライド（ＮａＢＨ４）等の水素供与性還元剤を添加する必要がなく、簡便な方法で親水性ポリマー被覆銅ナノ粒子を得ることが可能となる。特に、前記水素供与性還元剤を用いた場合には、銅イオンの還元反応が速く進行するため、銅ナノ粒子が粗大化し、粒径分布が広くなる傾向にあるため、前記水素供与性還元剤を使用しないことが好ましい。また、沸点が２００℃以上（好ましくは２２０℃以上、より好ましくは２３０℃以上）の前記アルコール系溶媒を用いることによって、高温での加熱が可能となり、銅イオンの還元反応を均一に進行させることができ、粒径分布が狭い銅ナノ粒子を得ることができる。
(Alcoholic solvent)
In the method for producing hydrophilic polymer-coated copper nanoparticles of the present invention, a diol having a boiling point of 200°C or higher (preferably 220°C or higher, more preferably 230°C or higher) and a boiling point of 200°C or higher (preferably 220°C) are used as the solvent. At least one alcohol solvent selected from the group consisting of diol monoalkyl ethers having a temperature of not less than 0°C, more preferably not less than 230°C) is used. Such an alcohol-based solvent acts as a reducing agent that advances the reduction reaction of copper ions at an appropriate rate. Therefore, in the method for producing a hydrophilic polymer-coated copper nanoparticle of the present invention, sodium hypophosphate (NaH 2 PO 2 ), hydrazine (N 2 H 4 ), hydrochloride (HCl), sodium borohydride (NaBH) are used. 4 ) It is not necessary to add a hydrogen donating reducing agent such as 4 ), and hydrophilic polymer-coated copper nanoparticles can be obtained by a simple method. In particular, when the hydrogen-donating reducing agent is used, the reduction reaction of copper ions proceeds rapidly, so that the copper nanoparticles tend to become coarse and the particle size distribution tends to be broad. Is preferably not used. Further, by using the alcohol solvent having a boiling point of 200° C. or higher (preferably 220° C. or higher, more preferably 230° C. or higher), heating at a high temperature becomes possible, and the reduction reaction of copper ions can proceed uniformly. And copper nanoparticles having a narrow particle size distribution can be obtained.
沸点が２００℃以上のジオールとしては、ジエチレングリコール（沸点：２４５℃）、トリエチレングリコール（沸点：２８７．４℃）、テトラエチレングリコール（沸点：３２８℃）、ペンタエチレングリコール（沸点：３８０℃）等が挙げられる。また、沸点が２００℃以上のジオールモノアルキルエーテルとしては、トリエチレングリコールモノメチルエーテル（沸点：２４８℃）、トリエチレングリコールモノエチルエーテル（沸点：２５６℃）、トリエチレングリコールモノブチルエーテル（沸点：２７１℃）、ジエチレングリコールモノエチルエーテル（沸点：２０２℃）、ジエチレングリコールモノブチルエーテル（沸点：２３０℃）等の前記ジオールのモノアルキルエーテルが挙げられる。このようなアルコール系溶媒は１種を単独で使用しても２種以上を併用してもよい。また、これらのアルコール系溶媒のうち、後述する、より好ましい温度範囲（２２０〜２５０℃）で加熱しても揮発しにくいという観点から、沸点が２４８℃以上のものが好ましい。 As the diol having a boiling point of 200° C. or higher, diethylene glycol (boiling point: 245° C.), triethylene glycol (boiling point: 287.4° C.), tetraethylene glycol (boiling point: 328° C.), pentaethylene glycol (boiling point: 380° C.), etc. Is mentioned. As the diol monoalkyl ether having a boiling point of 200° C. or higher, triethylene glycol monomethyl ether (boiling point: 248° C.), triethylene glycol monoethyl ether (boiling point: 256° C.), triethylene glycol monobutyl ether (boiling point: 271° C.) ), diethylene glycol monoethyl ether (boiling point: 202° C.), diethylene glycol monobutyl ether (boiling point: 230° C.) and the like. Such alcohol solvents may be used alone or in combination of two or more. Further, among these alcohol solvents, those having a boiling point of 248° C. or higher are preferable from the viewpoint of being hard to volatilize even when heated in a more preferable temperature range (220 to 250° C.) described later.
（銅塩）
本発明の親水性ポリマー被覆銅ナノ粒子の製造方法においては、銅塩として、炭酸銅及び水酸化銅からなる群から選択される少なくとも１種を使用する。このような銅塩は前記アルコール系溶媒に不溶又は難溶なものである。これらの銅塩は１種を単独で使用しても２種以上を併用してもよい。
(Copper salt)
In the method for producing the hydrophilic polymer-coated copper nanoparticles of the present invention, at least one selected from the group consisting of copper carbonate and copper hydroxide is used as the copper salt. Such a copper salt is insoluble or hardly soluble in the alcohol solvent. These copper salts may be used alone or in combination of two or more.
本発明の親水性ポリマー被覆銅ナノ粒子の製造方法においては、前記アルコール溶媒中で銅塩を熱分解して銅イオンを生成させるが、銅塩として前記アルコール系溶媒に不溶又は難溶なものを使用することによって、溶媒中に存在する銅イオンが少量となる。このような系において銅イオンを還元すると、生成する粒子核は少量であり、銅ナノ粒子は徐々に生成するため、親水性ポリマー被膜層が、銅ナノ粒子の表面に形成されやすく、かつ、安定に存在する。その結果、銅ナノ粒子の前記アルコール溶媒中での凝集を十分に抑制することができ、銅ナノ粒子の粗大化を防ぐことが可能となる。また、銅塩を徐々に溶解させて銅ナノ粒子を形成するため、多量の溶媒を必要とせず、溶媒量を少なくすることができる。その結果、溶媒の温度を均一に保持することができ、粒子径が均一な大量の銅ナノ粒子を容易に製造することが可能となる。 In the method for producing a hydrophilic polymer-coated copper nanoparticles of the present invention, a copper salt is thermally decomposed in the alcohol solvent to generate copper ions, but a copper salt that is insoluble or hardly soluble in the alcohol solvent is used. By using, the amount of copper ions present in the solvent will be small. When copper ions are reduced in such a system, a small amount of particle nuclei are generated and copper nanoparticles are gradually generated, so that a hydrophilic polymer coating layer is easily formed on the surface of the copper nanoparticles, and stable. Exists in. As a result, aggregation of the copper nanoparticles in the alcohol solvent can be sufficiently suppressed, and coarsening of the copper nanoparticles can be prevented. Moreover, since the copper salt is gradually dissolved to form the copper nanoparticles, a large amount of solvent is not required and the amount of solvent can be reduced. As a result, the temperature of the solvent can be kept uniform, and a large amount of copper nanoparticles having a uniform particle size can be easily produced.
一方、アルコール系溶媒に可溶な銅塩を使用すると、溶媒中には多くの銅イオンが生成する。このような系において銅イオンを還元すると、一度に多くの銅ナノ粒子が生成する。銅ナノ粒子が多量に生成すると、その表面に親水性ポリマー被膜層が形成される前に、粒子同士が凝集するため、粒子は粗大化して沈殿する。また、銅ナノ粒子は表面に親水性ポリマー被膜層が形成されないと、酸化されやすくなる。 On the other hand, when a copper salt soluble in an alcoholic solvent is used, many copper ions are generated in the solvent. When copper ions are reduced in such a system, many copper nanoparticles are produced at once. When a large amount of copper nanoparticles are generated, the particles agglomerate with each other before the hydrophilic polymer coating layer is formed on the surface of the particles, so that the particles become coarse and precipitate. Further, the copper nanoparticles are easily oxidized unless the hydrophilic polymer coating layer is formed on the surface.
（親水性ポリマー）
本発明の親水性ポリマー被覆銅ナノ粒子の製造方法に用いられる親水性ポリマーは、生成した銅ナノ粒子の表面に被膜層を形成し、前記アルコール系溶媒中での銅ナノ粒子の凝集を抑制し、銅ナノ粒子の粗大化を防ぐものである。このような親水性ポリマーとしては、ポリビニルピロリドン、ポリエチレングリコール、ポリビニルアルコール、ポリエチレンイミン、等が挙げられる。このような親水性ポリマーは１種を単独で使用しても２種以上を併用してもよい。また、これらの親水性ポリマーのうち、銅に安定に結合し、銅ナノ粒子が微粒子化しやすいという観点から、ポリビニルピロリドンが好ましい。
(Hydrophilic polymer)
The hydrophilic polymer used in the method for producing a hydrophilic polymer-coated copper nanoparticle of the present invention forms a coating layer on the surface of the produced copper nanoparticle, and suppresses aggregation of the copper nanoparticle in the alcohol solvent. The purpose is to prevent coarsening of copper nanoparticles. Examples of such hydrophilic polymers include polyvinylpyrrolidone, polyethylene glycol, polyvinyl alcohol, polyethyleneimine, and the like. Such hydrophilic polymers may be used alone or in combination of two or more. Further, among these hydrophilic polymers, polyvinylpyrrolidone is preferable from the viewpoint that it is stably bound to copper and the copper nanoparticles are easily made into fine particles.
本発明の親水性ポリマー被覆銅ナノ粒子の製造方法においては、前記アルコール系溶媒中の銅塩の濃度としては、０．００１〜１０ｍｏｌ／Ｌが好ましく、０．０１〜１ｍｏｌ／Ｌがより好ましい。銅塩の濃度が下限未満になると、銅ナノ粒子の生成量が少なくなる傾向にあり、他方、前記上限を超えると、銅塩の熱分解に要する時間が長くなる傾向にある。 In the method for producing a hydrophilic polymer-coated copper nanoparticle of the present invention, the concentration of the copper salt in the alcohol solvent is preferably 0.001 to 10 mol/L, more preferably 0.01 to 1 mol/L. If the concentration of the copper salt is less than the lower limit, the amount of copper nanoparticles produced tends to decrease, while if it exceeds the upper limit, the time required for the thermal decomposition of the copper salt tends to increase.
前記アルコール系溶媒中の親水性ポリマーの濃度としては、０．００１〜１０ｍｏｌ／Ｌが好ましく、０．０１〜１ｍｏｌ／Ｌがより好ましい。親水性ポリマーの濃度が下限未満になると、銅ナノ粒子の表面に親水性ポリマー被膜層が十分に形成されず、銅ナノ粒子が凝集して粗大化したり、酸化されたりする傾向にあり、他方、前記上限を超えると、余分な親水性ポリマーを除去するための洗浄操作が煩雑となり、実用的に好ましくない。 The concentration of the hydrophilic polymer in the alcoholic solvent is preferably 0.001 to 10 mol/L, more preferably 0.01 to 1 mol/L. When the concentration of the hydrophilic polymer is less than the lower limit, the hydrophilic polymer coating layer is not sufficiently formed on the surface of the copper nanoparticles, the copper nanoparticles tend to aggregate and coarsen, or tend to be oxidized, while, When the amount exceeds the upper limit, the washing operation for removing the excess hydrophilic polymer becomes complicated, which is not preferable in practice.
また、前記アルコール系溶媒中の前記親水性ポリマーと前記銅塩とのモル比（親水性ポリマー／銅塩）としては、３〜５０が好ましく、５〜３０がより好ましい。親水性ポリマー／銅塩が前記下限未満になると、銅ナノ粒子の表面に親水性ポリマー被膜層が十分に形成されず、銅ナノ粒子が凝集して粗大化したり、酸化されたりする傾向にある。他方、銅塩／親水性ポリマーが前記上限を超えると、余分な親水性ポリマーを除去するための洗浄操作が煩雑となり、実用的に好ましくない。 The molar ratio of the hydrophilic polymer to the copper salt in the alcoholic solvent (hydrophilic polymer/copper salt) is preferably 3 to 50, more preferably 5 to 30. If the hydrophilic polymer/copper salt is less than the lower limit, the hydrophilic polymer coating layer is not sufficiently formed on the surface of the copper nanoparticles, and the copper nanoparticles tend to aggregate and become coarse or oxidized. On the other hand, when the amount of the copper salt/hydrophilic polymer exceeds the above upper limit, the washing operation for removing the excess hydrophilic polymer becomes complicated, which is not practically preferable.
本発明の親水性ポリマー被覆銅ナノ粒子の製造方法に用いられる不活性ガスとして特に制限はなく、窒素ガス、アルゴンガスが挙げられる。 The inert gas used in the method for producing the hydrophilic polymer-coated copper nanoparticles of the present invention is not particularly limited, and examples thereof include nitrogen gas and argon gas.
本発明の親水性ポリマー被覆銅ナノ粒子の製造方法においては、前記銅塩を２００〜３００℃で加熱する。加熱温度が前記下限未満になると、銅イオンの還元反応が進行せず、銅ナノ粒子が生成しない。他方、加熱温度が前記上限を超えると、生成した銅ナノ粒子が凝集して粗大化する。また、最適な粒子径の銅ナノ粒子を比較的安全な反応温度で得るという観点から、前記加熱温度としては、２００〜２８０℃が好ましく、２２０〜２５０℃がより好ましい。 In the method for producing hydrophilic polymer-coated copper nanoparticles of the present invention, the copper salt is heated at 200 to 300°C. When the heating temperature is lower than the lower limit, the reduction reaction of copper ions does not proceed and copper nanoparticles are not generated. On the other hand, when the heating temperature exceeds the upper limit, the produced copper nanoparticles aggregate and become coarse. Further, from the viewpoint of obtaining copper nanoparticles having an optimum particle size at a relatively safe reaction temperature, the heating temperature is preferably 200 to 280°C, more preferably 220 to 250°C.
このようにして得られる親水性ポリマー被覆銅ナノ粒子は、平均粒子径が１０〜１００ｎｍであり、粒子径の相対標準偏差が３０％以下である銅ナノ粒子を含有するものであるため、ナノ粒子の特性を十分に発揮することができるものである。また、このような銅ナノ粒子の表面が親水性ポリマーで覆われているため、アルコール系溶媒等の水性溶媒や水に容易にかつ均一に分散させることが可能である。 The hydrophilic polymer-coated copper nanoparticles thus obtained contain copper nanoparticles having an average particle diameter of 10 to 100 nm and a relative standard deviation of the particle diameter of 30% or less. The characteristics of can be sufficiently exhibited. Further, since the surface of such copper nanoparticles is covered with the hydrophilic polymer, it can be easily and uniformly dispersed in an aqueous solvent such as an alcohol solvent or water.
＜親水性ポリマー被覆銅ナノ粒子＞
次に、本発明の親水性ポリマー被覆銅ナノ粒子について説明する。本発明の親水性ポリマー被覆銅ナノ粒子は、平均粒子径が１０〜１００ｎｍであり、粒子径の相対標準偏差が３０％以下である銅ナノ粒子と、この銅ナノ粒子の表面に配置されている親水性ポリマーからなる被覆層とを備えるものである。このような親水性ポリマー被覆銅ナノ粒子は、例えば、上述した本発明の親水性ポリマー被覆銅ナノ粒子の製造方法によって得ることができる。
<Copper nanoparticles coated with hydrophilic polymer>
Next, the hydrophilic polymer-coated copper nanoparticles of the present invention will be described. The hydrophilic polymer-coated copper nanoparticles of the present invention have an average particle diameter of 10 to 100 nm and a relative standard deviation of the particle diameter of 30% or less, and the copper nanoparticles are arranged on the surface of the copper nanoparticles. And a coating layer made of a hydrophilic polymer. Such hydrophilic polymer-coated copper nanoparticles can be obtained, for example, by the method for producing hydrophilic polymer-coated copper nanoparticles of the present invention described above.
（銅ナノ粒子）
本発明にかかる銅ナノ粒子は、平均粒子径が１０〜１００ｎｍのものである。平均粒子径が前記範囲内にある銅ナノ粒子は、ナノ粒子としての特性を十分に発揮することができ、殺菌作用に優れている。一方、平均粒子径が前記上限を超えると、ナノ粒子としての特性を十分に発揮することができず、殺菌作用を十分に発揮するためには、多量の銅ナノ粒子が必要になる。また、酸化されにくく、比較的大きな比表面積を有するという観点から、銅ナノ粒子平均粒子径としては、２０〜８０ｎｍが好ましく、３０〜７０ｎｍがより好ましい。
(Copper nanoparticles)
The copper nanoparticles according to the present invention have an average particle size of 10 to 100 nm. The copper nanoparticles having an average particle size within the above range can sufficiently exhibit the characteristics as nanoparticles and are excellent in bactericidal action. On the other hand, if the average particle diameter exceeds the upper limit, the characteristics as nanoparticles cannot be sufficiently exhibited, and a large amount of copper nanoparticles are required to sufficiently exhibit the bactericidal action. Further, from the viewpoint of being hardly oxidized and having a relatively large specific surface area, the average particle size of the copper nanoparticles is preferably 20 to 80 nm, more preferably 30 to 70 nm.
また、本発明にかかる銅ナノ粒子は、粒子径の相対標準偏差が３０％以下のものである。粒子径の相対標準偏差が前記範囲内にあると、ナノ粒子としての特性を十分に発揮することができ、殺菌作用に優れている。一方、粒子径の相対標準偏差が前記上限を超えると、ナノ粒子としての特性を十分に発揮することができず、殺菌作用を十分に発揮するためには、多量の銅ナノ粒子が必要になる。また、比較的少ない粒子量で十分な殺菌作用が得られるという観点から、粒子径の相対標準偏差としては、２６％以下が好ましく、２１％以下がより好ましい。 Further, the copper nanoparticles according to the present invention have a relative standard deviation of particle diameter of 30% or less. When the relative standard deviation of the particle diameter is within the above range, the characteristics as nanoparticles can be sufficiently exhibited and the bactericidal action is excellent. On the other hand, when the relative standard deviation of the particle diameter exceeds the upper limit, it is not possible to sufficiently exhibit the characteristics as nanoparticles, in order to sufficiently exhibit the bactericidal action, a large amount of copper nanoparticles are required. .. Further, from the viewpoint that a sufficient bactericidal action can be obtained with a relatively small amount of particles, the relative standard deviation of the particle diameter is preferably 26% or less, more preferably 21% or less.
なお、本発明において、銅ナノ粒子の平均粒子径及び相対標準偏差は以下の方法により測定されるものである。すなわち、本発明の親水性ポリマー被覆銅ナノ粒子の透過型電子顕微鏡（ＴＥＭ）写真において、５０個の親水性ポリマー被覆銅ナノ粒子を無作為に抽出し、各銅ナノ粒子の粒子径（単位：ｎｍ）を測定する。得られた５０個の銅ナノ粒子の粒子径を算術平均して、これを銅ナノ粒子の平均粒子径（単位：ｎｍ）とする。また、得られた５０個の銅ナノ粒子の粒径分布から粒子径の標準偏差（単位：ｎｍ）を求め、これを平均粒子径で割ったもの（粒子径の標準偏差／平均粒子径）のパーセント表示を相対標準偏差（単位：％）とする。 In addition, in this invention, the average particle diameter and relative standard deviation of copper nanoparticles are measured by the following methods. That is, in a transmission electron microscope (TEM) photograph of the hydrophilic polymer-coated copper nanoparticles of the present invention, 50 hydrophilic polymer-coated copper nanoparticles were randomly extracted, and the particle diameter of each copper nanoparticle (unit: nm) is measured. The particle diameters of the obtained 50 copper nanoparticles are arithmetically averaged to obtain the average particle diameter (unit: nm) of the copper nanoparticles. In addition, the standard deviation (unit: nm) of the particle size was obtained from the particle size distribution of the obtained 50 copper nanoparticles, and this was divided by the average particle size (standard deviation of the particle size/average particle size). The percentage display is the relative standard deviation (unit: %).
（親水性ポリマー被膜層）
本発明にかかる親水性ポリマーからなる被膜層（以下、「親水性ポリマー被覆層」という。）は、前記銅ナノ粒子の表面に配置されており、溶媒中（特に、水性溶媒中）での凝集を抑制するものである。このような親水性ポリマー被覆層としては、前述の本発明の親水性ポリマー被覆銅ナノ粒子の製造方法において例示した親水性ポリマーにより形成された被覆層が挙げられる。
(Hydrophilic polymer coating layer)
The coating layer made of the hydrophilic polymer according to the present invention (hereinafter referred to as “hydrophilic polymer coating layer”) is disposed on the surface of the copper nanoparticles and aggregates in a solvent (particularly in an aqueous solvent). Is to suppress. Examples of such a hydrophilic polymer coating layer include a coating layer formed of the hydrophilic polymer exemplified in the above-described method for producing hydrophilic polymer-coated copper nanoparticles of the present invention.
また、本発明にかかる親水性ポリマー被覆層としては、前記水素供与性還元剤を含まないものが好ましい。親水性ポリマー被覆層が前記水素供与性還元剤を含む親水性ポリマー被覆銅ナノ粒子（すなわち、前記水素供与性還元剤を用いて製造した親水性ポリマー被覆銅ナノ粒子）は、平均粒子径が大きく、粒径分布が広くなる傾向にあり、ナノ粒子の特性を十分に発揮することが困難となる傾向にある。 In addition, the hydrophilic polymer coating layer according to the present invention preferably does not contain the hydrogen donating reducing agent. The hydrophilic polymer-coated copper nanoparticles whose hydrophilic polymer coating layer contains the hydrogen-donating reducing agent (that is, the hydrophilic polymer-coated copper nanoparticles produced by using the hydrogen-donating reducing agent) have a large average particle size. However, the particle size distribution tends to be broad, and it tends to be difficult to sufficiently exhibit the characteristics of the nanoparticles.
本発明の親水性ポリマー層被覆銅ナノ粒子において、親水性ポリマー被覆層と銅ナノ粒子とのモル比（親水性ポリマー被覆層／銅ナノ粒子）としては、０．００１〜０．１が好ましく、０．００２〜０．０５がより好ましい。また、親水性ポリマー被覆層の厚さと銅ナノ粒子の粒子径との比（層厚／粒子径）としては、０．０１〜０．２が好ましく、０．０２〜０．１５がより好ましい。親水性ポリマー被覆層／銅ナノ粒子、又は、層厚／粒子径が前記下限未満になると、銅ナノ粒子が凝集しやすい傾向にあり、他方、前記上限を超えると、親水性ポリマーが阻害要因となって殺菌作用が発現しない傾向にある。 In the hydrophilic polymer layer-coated copper nanoparticles of the present invention, the molar ratio of the hydrophilic polymer coating layer and the copper nanoparticles (hydrophilic polymer coating layer/copper nanoparticles) is preferably 0.001 to 0.1, 0.002-0.05 is more preferable. The ratio of the thickness of the hydrophilic polymer coating layer to the particle size of the copper nanoparticles (layer thickness/particle size) is preferably 0.01 to 0.2, more preferably 0.02 to 0.15. If the hydrophilic polymer coating layer/copper nanoparticles or the layer thickness/particle diameter is less than the lower limit, the copper nanoparticles tend to aggregate, while if the upper limit is exceeded, the hydrophilic polymer becomes an inhibitory factor. Therefore, there is a tendency that the bactericidal action does not appear.
このような本発明の親水性ポリマー被覆銅ナノ粒子は、平均粒子径が小さく、粒径分布が狭い銅ナノ粒子を含有するものであるため、ナノ粒子の特性を十分に発揮することができ、殺菌作用に優れている。また、このような銅ナノ粒子の表面が親水性ポリマーで覆われているため、本発明の親水性ポリマー被覆銅ナノ粒子はアルコール系溶媒等の水性溶媒や水に容易にかつ均一に分散させることが可能である。 Such a hydrophilic polymer-coated copper nanoparticles of the present invention has a small average particle size, and since it contains copper nanoparticles having a narrow particle size distribution, it is possible to sufficiently exhibit the characteristics of the nanoparticles. Excellent bactericidal action. Further, since the surface of such copper nanoparticles are covered with a hydrophilic polymer, the hydrophilic polymer-coated copper nanoparticles of the present invention should be easily and uniformly dispersed in an aqueous solvent such as an alcohol solvent or water. Is possible.
＜殺菌材料＞
本発明の殺菌材料は、前記本発明の親水性ポリマー被覆銅ナノ粒子を含有するものである。上述したように、本発明の親水性ポリマー被覆銅ナノ粒子は、水や水性溶媒に対して高い分散性を示すため、水や水性溶媒に容易に分散させることが可能である。また、本発明の親水性ポリマー被覆銅ナノ粒子が殺菌作用に優れているため、本発明の殺菌材料は、親水性ポリマー被覆銅ナノ粒子の濃度が低い場合（例えば、３０〜１００質量ｐｐｍ、好ましくは３０〜８０質量ｐｐｍ、より好ましくは３０〜５０質量ｐｐｍ）でも十分に優れた殺菌作用を示す。
<Sterilizing material>
The sterilizing material of the present invention contains the hydrophilic polymer-coated copper nanoparticles of the present invention. As described above, the hydrophilic polymer-coated copper nanoparticles of the present invention exhibit high dispersibility in water or an aqueous solvent, and thus can be easily dispersed in water or an aqueous solvent. Moreover, since the hydrophilic polymer-coated copper nanoparticles of the present invention are excellent in bactericidal action, the sterilizing material of the present invention has a low concentration of the hydrophilic polymer-coated copper nanoparticles (for example, 30 to 100 mass ppm, preferably Shows a sufficiently excellent bactericidal action even at 30-80 mass ppm, more preferably 30-50 mass ppm.
以下、実施例及び比較例に基づいて本発明をより具体的に説明するが、本発明は以下の実施例に限定されるものではない。 Hereinafter, the present invention will be described more specifically based on Examples and Comparative Examples, but the present invention is not limited to the following Examples.
（実施例１）
フラスコにトリエチレングリコール（ＨＯ（ＣＨ２）２Ｏ（ＣＨ２）２Ｏ（ＣＨ２）２ＯＨ）１００ｍｌ及びポリビニルピロリドン（重量平均分子量：５５０００）２００ｍｍｏｌを入れ、これに炭酸銅（ＣｕＣＯ３・Ｃｕ（ＯＨ）２・Ｈ２Ｏ）１０ｍｍｏｌを添加したところ、炭酸銅はトリエチレングリコールにほとんど溶解せずに沈殿した。これに窒素ガスを５Ｌ／分で流しながら２２０℃で２時間加熱したところ、微粒子が生成した。得られた微粒子をエタノールで洗浄した後、遠心分離（１５０００ｒｐｍ、３０分間）を施して回収した。
(Example 1)
Flask triethylene glycol (HO (CH 2) 2 O (CH 2) 2 O (CH 2) 2 OH) 100ml and polyvinylpyrrolidone (weight average molecular weight: 55000) 200 mmol placed, to which copper carbonate (CuCO 3 · Cu When (OH) 2 ·H 2 O) (10 mmol) was added, copper carbonate was hardly dissolved in triethylene glycol and precipitated. When this was heated at 220° C. for 2 hours while flowing nitrogen gas at 5 L/min, fine particles were generated. The obtained fine particles were washed with ethanol, and then centrifuged (15000 rpm, 30 minutes) to collect them.
（実施例２）
トリエチレングリコールの代わりにテトラエチレングリコール（ＨＯ（ＣＨ２）２Ｏ（ＣＨ２）２Ｏ（ＣＨ２）２Ｏ（ＣＨ２）２ＯＨ）１００ｍｌを用いた以外は実施例１と同様にして微粒子を得た。なお、炭酸銅はテトラエチレングリコールにほとんど溶解せずに沈殿した。得られた微粒子を実施例１と同様にして回収した。
(Example 2)
Tetraethylene glycol instead of triethylene glycol (HO (CH 2) 2 O (CH 2) 2 O (CH 2) 2 O (CH 2) 2 OH) except for using 100ml in the same manner as in Example 1 particles Got The copper carbonate was hardly dissolved in tetraethylene glycol and was precipitated. The obtained fine particles were collected in the same manner as in Example 1.
（実施例３）
トリエチレングリコールの代わりにトリエチレングリコールモノメチルエーテル（ＨＯ（ＣＨ２）２Ｏ（ＣＨ２）２Ｏ（ＣＨ２）２ＯＣＨ３）１００ｍｌを用いた以外は実施例１と同様にして微粒子を得た。なお、炭酸銅はトリエチレングリコールモノメチルエーテルにほとんど溶解せずに沈殿した。得られた微粒子を実施例１と同様にして回収した。
(Example 3)
Except for using triethylene triethylene glycol monomethyl ether in place of ethylene glycol (HO (CH 2) 2 O (CH 2) 2 O (CH 2) 2 OCH 3) 100ml in the same manner as in Example 1 to obtain fine particles .. Incidentally, copper carbonate was hardly dissolved in triethylene glycol monomethyl ether and precipitated. The obtained fine particles were collected in the same manner as in Example 1.
（実施例４）
重量平均分子量が５５０００のポリビニルピロリドンの代わりに重量平均分子量が４００００のポリビニルピロリドン２００ｍｍｏｌを用いた以外は実施例１と同様にして微粒子を得た。なお、炭酸銅はトリエチレングリコールにほとんど溶解せずに沈殿した。得られた微粒子を実施例１と同様にして回収した。
(Example 4)
Fine particles were obtained in the same manner as in Example 1 except that 200 mmol of polyvinylpyrrolidone having a weight average molecular weight of 40,000 was used instead of polyvinylpyrrolidone having a weight average molecular weight of 55,000. The copper carbonate was almost insoluble in triethylene glycol and precipitated. The obtained fine particles were collected in the same manner as in Example 1.
（実施例５）
ポリビニルピロリドンの量を３００ｍｍｏｌに変更した以外は実施例１と同様にして微粒子を得た。なお、炭酸銅はトリエチレングリコールにほとんど溶解せずに沈殿した。得られた微粒子を実施例１と同様にして回収した。
(Example 5)
Fine particles were obtained in the same manner as in Example 1 except that the amount of polyvinylpyrrolidone was changed to 300 mmol. The copper carbonate was almost insoluble in triethylene glycol and precipitated. The obtained fine particles were collected in the same manner as in Example 1.
（実施例６）
加熱温度を２００℃に変更した以外は実施例１と同様にして微粒子を得た。なお、炭酸銅はトリエチレングリコールにほとんど溶解せずに沈殿した。得られた微粒子を実施例１と同様にして回収した。
(Example 6)
Fine particles were obtained in the same manner as in Example 1 except that the heating temperature was changed to 200°C. The copper carbonate was almost insoluble in triethylene glycol and precipitated. The obtained fine particles were collected in the same manner as in Example 1.
（実施例７）
加熱温度を２４０℃に変更した以外は実施例１と同様にして微粒子を得た。なお、炭酸銅はトリエチレングリコールにほとんど溶解せずに沈殿した。得られた微粒子を実施例１と同様にして回収した。
(Example 7)
Fine particles were obtained in the same manner as in Example 1 except that the heating temperature was changed to 240°C. The copper carbonate was almost insoluble in triethylene glycol and precipitated. The obtained fine particles were collected in the same manner as in Example 1.
（比較例１）
トリエチレングリコールの代わりにジエチレングリコール（ＨＯ（ＣＨ２）２Ｏ（ＣＨ２）２ＯＨ）１００ｍｌを用いた以外は実施例１と同様にして微粒子を得た。なお、炭酸銅はジエチレングリコールにほとんど溶解せずに沈殿した。得られた微粒子を実施例１と同様にして回収した。
( Comparative example 1 )
Fine particles were obtained in the same manner as in Example 1 except that 100 ml of diethylene glycol (HO(CH 2 ) 2 O(CH 2 ) 2 OH) was used instead of triethylene glycol. The copper carbonate was hardly dissolved in diethylene glycol and was precipitated. The obtained fine particles were collected in the same manner as in Example 1.
（実施例８）
重量平均分子量が５５０００のポリビニルピロリドンの代わりに重量平均分子量が１００００のポリビニルピロリドン２００ｍｍｏｌを用いた以外は実施例１と同様にして微粒子を得た。なお、炭酸銅はトリエチレングリコールにほとんど溶解せずに沈殿した。得られた微粒子を実施例１と同様にして回収した。
(Example 8 )
Fine particles were obtained in the same manner as in Example 1 except that 200 mmol of polyvinylpyrrolidone having a weight average molecular weight of 10,000 was used in place of polyvinylpyrrolidone having a weight average molecular weight of 55,000. The copper carbonate was almost insoluble in triethylene glycol and precipitated. The obtained fine particles were collected in the same manner as in Example 1.
（実施例９）
ポリビニルピロリドンの量を１００ｍｍｏｌに変更した以外は実施例１と同様にして微粒子を得た。なお、炭酸銅はトリエチレングリコールにほとんど溶解せずに沈殿した。得られた微粒子を実施例１と同様にして回収した。
(Example 9 )
Fine particles were obtained in the same manner as in Example 1 except that the amount of polyvinylpyrrolidone was changed to 100 mmol. The copper carbonate was almost insoluble in triethylene glycol and precipitated. The obtained fine particles were collected in the same manner as in Example 1.
（比較例２）
加熱温度を１６０℃に変更した以外は実施例１と同様にして微粒子の調製を試みたが、粒子は全く生成しなかった。なお、炭酸銅はトリエチレングリコールにほとんど溶解せずに沈殿した。
(Comparative example 2 )
An attempt was made to prepare fine particles in the same manner as in Example 1 except that the heating temperature was changed to 160° C., but no particles were formed. The copper carbonate was almost insoluble in triethylene glycol and precipitated.
（比較例３）
トリエチレングリコールの代わりにエチレングリコール（ＨＯ（ＣＨ２）２Ｏ（ＣＨ２）２ＯＨ）１００ｍｌを用い、ポリビニルピロリドンの量を１００ｍｍｏｌに変更し、加熱温度を１９７℃に変更し、加熱時間を３０分間に変更した以外は実施例１と同様にして微粒子を得た。なお、炭酸銅はエチレングリコールにほとんど溶解せずに沈殿した。得られた微粒子を実施例１と同様にして回収した。
(Comparative example 3 )
100 ml of ethylene glycol (HO(CH 2 ) 2 O(CH 2 ) 2 OH) was used instead of triethylene glycol, the amount of polyvinylpyrrolidone was changed to 100 mmol, the heating temperature was changed to 197° C., and the heating time was 30 Fine particles were obtained in the same manner as in Example 1 except that the time was changed. The copper carbonate was almost insoluble in ethylene glycol and precipitated. The obtained fine particles were collected in the same manner as in Example 1.
（比較例４）
トリエチレングリコールの代わりにグリセリン（Ｃ３Ｈ５（ＯＨ）３）１００ｍｌを用い、ポリビニルピロリドンの量を１００ｍｍｏｌに変更し、加熱時間を３０分間に変更した以外は実施例１と同様にして微粒子を得た。なお、炭酸銅はグリセリンにほとんど溶解せずに沈殿した。得られた微粒子を実施例１と同様にして回収した。
(Comparative example 4 )
Fine particles were prepared in the same manner as in Example 1 except that 100 ml of glycerin (C 3 H 5 (OH) 3 ) was used instead of triethylene glycol, the amount of polyvinylpyrrolidone was changed to 100 mmol, and the heating time was changed to 30 minutes. Obtained. Incidentally, copper carbonate was hardly dissolved in glycerin and was precipitated. The obtained fine particles were collected in the same manner as in Example 1.
（比較例５）
ポリビニルピロリドンの量を１００ｍｍｏｌに変更し、炭酸銅の代わりに硫酸銅５水和物（ＣｕＳＯ４・５Ｈ２Ｏ）２０ｍｍｏｌを用いた以外は実施例１と同様にして微粒子を得た。なお、硫酸銅５水和物はトリエチレングリコールに溶解した。得られた微粒子を実施例１と同様にして回収した。
(Comparative example 5 )
Fine particles were obtained in the same manner as in Example 1 except that the amount of polyvinylpyrrolidone was changed to 100 mmol and 20 mmol of copper sulfate pentahydrate (CuSO 4 .5H 2 O) was used instead of copper carbonate. The copper sulfate pentahydrate was dissolved in triethylene glycol. The obtained fine particles were collected in the same manner as in Example 1.
（比較例６）
フラスコにトリエチレングリコール（ＨＯ（ＣＨ２）２Ｏ（ＣＨ２）２Ｏ（ＣＨ２）２ＯＨ）１００ｍｌ及びポリビニルピロリドン（重量平均分子量：５５０００）１００ｍｍｏｌを入れ、これに炭酸銅（ＣｕＣＯ３・Ｃｕ（ＯＨ）２・Ｈ２Ｏ）１０ｍｍｏｌ及びソジウムハイポフォスフェート（ＮａＨ２ＰＯ２・Ｈ２Ｏ）８０ｍｍｏｌを添加した以外は実施例１と同様にして微粒子を得た。なお、炭酸銅はトリエチレングリコールにほとんど溶解せずに沈殿した。得られた微粒子を実施例１と同様にして回収した。
(Comparative example 6 )
Flask triethylene glycol (HO (CH 2) 2 O (CH 2) 2 O (CH 2) 2 OH) 100ml and polyvinylpyrrolidone (weight average molecular weight: 55000) were placed 100 mmol, this copper carbonate (CuCO 3 · Cu (OH) 2 · H 2 O ) except for adding 10mmol and sodium hypo phosphate (NaH 2 PO 2 · H 2 O) 80mmol got particles in the same manner as in example 1. The copper carbonate was almost insoluble in triethylene glycol and precipitated. The obtained fine particles were collected in the same manner as in Example 1.
（比較例７）
トリエチレングリコールの代わりにトリエチレングリコールジメチルエーテル（Ｈ３ＣＯ（ＣＨ２）２Ｏ（ＣＨ２）２Ｏ（ＣＨ２）２ＯＣＨ３）１００ｍｌを用いた以外は実施例１と同様にして微粒子の調製を試みたが、ポリビニルピロリドンがトリエチレングリコールジメチルエーテルにほとんど溶解せず、粒子の合成は困難であった。
(Comparative Example 7 )
Except for using triethylene triethylene glycol dimethyl ether in place of ethylene glycol (H 3 CO (CH 2) 2 O (CH 2) 2 O (CH 2) 2 OCH 3) 100ml in the same manner as in Example 1 Preparation of microparticles However, polyvinylpyrrolidone was hardly dissolved in triethylene glycol dimethyl ether, and it was difficult to synthesize particles.
＜銅ナノ粒子の平均粒子径及び相対標準偏差＞
実施例１〜９及び比較例１、３〜６で得られた微粒子をそれぞれエタノールに分散させ、この分散液をエラスチックカーボン支持膜（高分子材料膜（１５〜２０ｎｍ厚）＋カーボン膜（２０〜２５ｎｍ厚））付きＣｕマイクログリッド（応研商事（株）製）上に滴下した後、自然乾燥させて観察用試料を作製した。この観察用試料を、透過型電子顕微鏡（ＴＥＭ、日本電子（株）製「ＪＥＭ−２０００ＥＸ」）を用いて加速電圧２００ｋＶで観察した。
<Average particle size and relative standard deviation of copper nanoparticles>
The fine particles obtained in Example 1-9 and Comparative Example 1,3～6 were respectively dispersed in ethanol, the dispersion Heras tic carbon support film (a polymer material film (15-20 nm thick) + carbon film (20 (25 nm thickness)) on a Cu micro grid (manufactured by Oken Shoji Co., Ltd.) and then naturally dried to prepare an observation sample. This observation sample was observed at an acceleration voltage of 200 kV using a transmission electron microscope (TEM, "JEM-2000EX" manufactured by JEOL Ltd.).
実施例１〜９及び比較例１、３〜６で得られた微粒子のＴＥＭ写真において、５０個の微粒子を無作為に抽出して銅ナノ粒子の粒子径を測定し、銅ナノ粒子の平均粒子径及び相対標準偏差を求めた。その結果を表１〜表２に示す。なお、微粒子のＴＥＭ写真の例として、実施例１及び比較例１、３、４で得られた微粒子のＴＥＭ写真を図１〜図４に示す。 In the TEM photograph of the fine particles obtained in Examples 1-9 and Comparative Examples 1,3～6, and randomly measures the particle size of the copper nanoparticles 50 fine, average particle copper nanoparticles The diameter and relative standard deviation were determined. The results are shown in Tables 1 and 2. As an example of TEM photographs of the fine particles, TEM photographs of the fine particles obtained in Example 1 and Comparative Examples 1 , 3 and 4 are shown in FIGS.
表１に示した結果から明らかなように、沸点が２００℃以上のジオール中又は沸点が２００℃以上のジオールモノアルキルエーテル中、親水性ポリマーの共存下で、炭酸銅に２００〜３００℃で加熱処理を施すことによって、表面が親水性ポリマーで被覆された、平均粒子径が１０〜１００ｎｍであり、粒子径の相対標準偏差が３０％以下である銅ナノ粒子が得られることがわかった。 As is clear from the results shown in Table 1, copper carbonate was heated at 200 to 300° C. in a diol having a boiling point of 200° C. or higher or in a diol monoalkyl ether having a boiling point of 200° C. or higher in the presence of a hydrophilic polymer. It was found that by the treatment, copper nanoparticles having a surface coated with a hydrophilic polymer, an average particle diameter of 10 to 100 nm, and a relative standard deviation of the particle diameter of 30% or less can be obtained.
一方、表２に示した結果から明らかなように、加熱温度が２００℃未満の場合（比較例２）及び溶媒としてジオールのジアルキルエーテルを用いた場合（比較例７）には、銅ナノ粒子が形成されないことがわかった。また、溶媒としてエチレングリコールを用いた場合（比較例３）、溶媒としてトリオールを用いた場合（比較例４）、及びジオールに溶解する銅塩を用いた場合（比較例５）には、銅ナノ粒子の平均粒子径が１００ｎｍを超えることがわかった。さらに、溶媒としてトリオールを用いた場合（比較例４）、ジオールに溶解する銅塩を用いた場合（比較例５）、及び水素供与性還元剤を用いた場合（比較例６）には、銅ナノ粒子の粒子径の相対標準偏差が３０％を超えることがわかった。 On the other hand, as is clear from the results shown in Table 2, when the heating temperature is less than 200° C. (Comparative Example 2 ) and when the dialkyl ether of diol is used as the solvent (Comparative Example 7 ), copper nanoparticles are present. It was found that it did not form. Further, when ethylene glycol was used as a solvent (Comparative Example 3 ), triol was used as a solvent (Comparative Example 4 ), and when a copper salt soluble in a diol was used (Comparative Example 5 ), copper nano-particles were used. It was found that the average particle size of the particles exceeds 100 nm. Further, when triol was used as a solvent (Comparative Example 4 ), when a copper salt soluble in diol was used (Comparative Example 5 ), and when a hydrogen donating reducing agent was used (Comparative Example 6 ), copper was used. It was found that the relative standard deviation of the particle size of the nanoparticles exceeds 30%.
＜親水性ポリマー被覆層の分析＞
実施例１〜９及び比較例１、３〜６で得られた微粒子について、Ｘ線光電子分光分析装置（アルバック・ファイ（株）製「Ｑｕａｎｔｅｒａ ＳＸＭ」）を用い、Ｘ線源：単色化されたＡｌＫα線、光電子取出角：４５°、分析領域：約２００μｍφ、パスエネルギー：２６ｅＶ、エネルギーステップ：０．１ｅＶの条件で、Ｘ線光電子スペクトル（ＸＰＳ）を測定した。その結果、いずれの微粒子においても、Ｎ１ｓスペクトルからＮ−Ｃ＝Ｏの存在が検知され、Ｃｕナノ粒子の表面にはポリビニルピロリドンからなる被覆層が形成していることが確認された。なお、ＸＰＳの例として、実施例１で得られた微粒子のＮ１ｓスペクトルを図５に示す。
<Analysis of hydrophilic polymer coating layer>
The fine particles obtained in Example 1-9 and Comparative Example 1,3～6, using X-ray photoelectron spectroscopy apparatus (ULVAC-PHI Co. "Quantera SXM"), X-ray source: The monochromatic An X-ray photoelectron spectrum (XPS) was measured under the conditions of AlKα ray, photoelectron take-off angle: 45°, analysis region: about 200 μmφ, pass energy: 26 eV, energy step: 0.1 eV. As a result, the presence of N—C═O was detected from the N1s spectrum in all of the fine particles, and it was confirmed that a coating layer made of polyvinylpyrrolidone was formed on the surface of the Cu nanoparticles. As an example of XPS, the N1s spectrum of the fine particles obtained in Example 1 is shown in FIG.
＜銅ナノ粒子の殺菌作用＞
実施例１で得られた微粒子（親水性ポリマー被覆銅ナノ粒子）をエチレングリコール（ＥＧ）に分散し、３６０質量ｐｐｍの銅コロイドＥＧ溶液を調製した。この銅コロイドＥＧ溶液を純粋で１０倍に希釈し、３６質量ｐｐｍの銅コロイド水溶液を調製した。これらの銅コロイド溶液を用いて以下の方法により銅ナノ粒子の殺菌作用を評価した。先ず、大腸菌を含む水溶液（菌濃度：１００万個／ｍｌ）１００ｍｌを１０ｍｌのＬＢ培地に植菌し、３７℃、１００ｒｐｍで１５時間振とう培養を行なった（前培養）。得られた培養液を生理食塩水で５００００倍に希釈した後、得られた希釈培養液０．５ｍｌを試験管に入れた。この試験管に２×ＬＢ培地２．５ｍｌ、滅菌水１．５ｍｌ、及び前記銅コロイドＥＧ溶液又は銅コロイド水溶液を０．５ｍｌ添加し、それぞれ試料溶液を調製した。また、銅コロイド溶液の代わりに生理食塩水又はエチレングリコールを０．５ｍｌ添加し、対照用試料溶液（対象水溶液及び対象ＥＧ溶）も調製した。これらの試料溶液を３７℃、１００ｒｐｍで振とうし、振とう開始直後（０時間）、振とう開始から６時間経過後及び２４時間経過後の試料溶液を０．１ｍｌサンプリングし、それぞれＬＢ寒天プレートに撒き、このＬＢ寒天プレートを３７℃で２４時間静置して大腸菌を培養し、ＬＢ寒天プレート上に形成したコロニーをカウントして試料溶液中の生菌数を求めた。その結果を図６に示す。
<Bactericidal action of copper nanoparticles>
The fine particles (hydrophilic polymer-coated copper nanoparticles) obtained in Example 1 were dispersed in ethylene glycol (EG) to prepare a 360 mass ppm copper colloid EG solution. This copper colloid EG solution was diluted 10 times with pure water to prepare a 36 mass ppm copper colloid aqueous solution. The bactericidal action of copper nanoparticles was evaluated by the following method using these copper colloid solutions. First, 100 ml of an aqueous solution containing Escherichia coli (bacterial concentration: 1 million cells/ml) was inoculated into 10 ml of LB medium, and shake culture was carried out at 37° C. and 100 rpm for 15 hours (preculture). The obtained culture broth was diluted 50,000 times with physiological saline, and 0.5 ml of the diluted culture broth obtained was placed in a test tube. To this test tube, 2.5 ml of 2×LB medium, 1.5 ml of sterilized water, and 0.5 ml of the copper colloid EG solution or the copper colloid aqueous solution were added to prepare respective sample solutions. In addition, 0.5 ml of physiological saline or ethylene glycol was added instead of the copper colloid solution to prepare a control sample solution (target solution and target EG solution). These sample solutions were shaken at 37° C. and 100 rpm, and immediately after the start of shaking (0 hour), 0.1 ml of the sample solution was sampled 6 hours and 24 hours after the start of shaking, and LB agar plates were respectively sampled. The LB agar plate was allowed to stand at 37° C. for 24 hours to culture Escherichia coli, and the colonies formed on the LB agar plate were counted to determine the viable cell count in the sample solution. The result is shown in FIG.
図６に示した結果から明らかなように、銅ナノ粒子を添加しなかった場合には、振とう開始後、大腸菌が増殖したが、銅ナノ粒子を添加した場合には、振とう開始から６時間経過後に大腸菌が死滅し、実施例１で得られた親水性ポリマー被覆銅ナノ粒子は殺菌作用を有するものであることがわかった。 As is clear from the results shown in FIG. 6, when the copper nanoparticles were not added, Escherichia coli proliferated after the start of shaking, but when the copper nanoparticles were added, 6 times from the start of shaking. After the passage of time, Escherichia coli was killed, and it was found that the hydrophilic polymer-coated copper nanoparticles obtained in Example 1 had a bactericidal action.
以上説明したように、本発明によれば、水素供与性還元剤を用いることなく、粒径分布が狭く、水に分散させることが可能な銅ナノ粒子を簡便な方法で得ることが可能となる。 As described above, according to the present invention, copper nanoparticles having a narrow particle size distribution and capable of being dispersed in water can be obtained by a simple method without using a hydrogen-donating reducing agent. ..
したがって、本発明の親水性ポリマー被覆銅ナノ粒子は、水分散性に優れるため、殺菌材料等の、銅ナノ粒子を水に分散させる必要がある用途に有用である。 Therefore, since the hydrophilic polymer-coated copper nanoparticles of the present invention have excellent water dispersibility, they are useful for applications such as bactericidal materials that require the copper nanoparticles to be dispersed in water.
また、本発明の親水性ポリマー被覆銅ナノ粒子は、殺菌作用に優れているため、殺菌材料として有用である。 Further, the hydrophilic polymer-coated copper nanoparticles of the present invention have an excellent bactericidal action, and thus are useful as a bactericidal material.
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