JP3212973B2 - Manufacturing method of metal products with excellent antibacterial properties - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal product excellent in antibacterial properties, which is suitable for living-related articles, medical equipment, building materials, etc., and in particular, imparts antibacterial properties to a metal product processed into a final shape. About the method.

[0002]

2. Description of the Related Art It has long been known that silver (Ag) and copper (Cu) have an action of suppressing the growth of pathogenic bacteria represented by Escherichia coli and Salmonella. Recently, materials having an effect of inhibiting bacterial growth (hereinafter referred to as antibacterial properties) using these metals have been developed. For example, JP-A-8-4908
No. 5 publication, Ag sputtering by magnet sputtering
A stainless steel sheet having excellent antibacterial properties in which a metal layer or an alloy layer of Cr, Ti, Ni, Fe or the like containing Cu is formed on the surface of a stainless steel base material is disclosed. In this steel sheet, it is preferable to form an alloy layer or a metal layer containing 19 to 60% by weight of Ag.

Further, Japanese Patent Application Laid-Open No. 8-156175 proposes a coated steel sheet which can suppress the propagation of bacteria by applying a pigment containing silver. However, in the above-described method of forming an alloy layer or a metal layer containing an antibacterial metal on the surface of a steel sheet, or a method of applying a pigment containing an antibacterial metal, a layer containing the antibacterial metal is formed by drawing or polishing the surface. Is removed or removed, and the effect cannot be expected. Further, in applications such as kitchen supplies, there is also a problem that the antibacterial property cannot be maintained for a long time because the surface is rubbed by cleaning.

[0004] JP-A-8-239726 discloses that the weight ratio is
Iron: 10 to 80%, Aluminum: 1 to 10%, or further contains 1 to 15% of any one or more of chromium, nickel, manganese, and silver, with the balance being copper and unavoidable impurities, antibacterial and sea resistant A living material is disclosed. However, this material is a copper-based alloy or an iron-based alloy containing 1 to 10% of aluminum, and has low workability. For example, there is a problem in providing a use for forming a thin plate such as tableware, kitchenware, and electric parts. Had left.

To cope with such a problem, Japanese Unexamined Patent Publication No. Hei 8-104953 discloses an austenitic stainless steel containing 1.1 to 3.5% by weight of Cu and having an improved antibacterial property.
No. 457 discloses that Cu is 0.5 to 4.0% by weight and Ag is 0.05 to 1.0% by weight.
The austenitic stainless steel containing anti-bacterial property by weight percent contains Cu.
-5.0% by weight of martensitic stainless steel having improved antibacterial properties, and JP-A-9-170053 discloses that
Ferritic stainless steel containing 0.4 to 3.0% by weight and having improved antibacterial properties has been proposed.

However, in order to exhibit antibacterial properties, it is necessary for Cu to be dissolved as ions from the surface of the steel sheet. The dissolution of Cu as ions means that the passive film is destroyed at that location, and even if the antibacterial property is improved, the corrosion resistance is significantly deteriorated. Therefore, it was difficult to achieve both antibacterial properties and corrosion resistance in stainless steel containing a large amount of Cu.

[0007] Japanese Patent Application Laid-Open No. Hei 10-259456 discloses a composition containing 8% by weight or more of Cr and 0.05 to 1.0% by weight of Ag and having a minor axis of 10%.
An antibacterial stainless steel sheet in which an Ag phase of μm or less is dispersed in a matrix in an area fraction of 0.03% or more has been proposed.
However, in the technique described in JP-A-10-259456, it is practically difficult to control the minor axis of the Ag phase to 10 μm or less, and the area ratio of the Ag phase having the minor axis of 10 μm or less is 0.03% or less.
In order to achieve the above, a large amount of Ag must be added, and as a result, there is a problem that workability, corrosion resistance, and surface properties are reduced.

[0008] Generally, a stainless steel material is made into a final product through a descaling step such as pickling. Antibacterial elements such as Cu and Ag that exist in the steel surface layer cannot be dissolved as ions when the steel surface is covered with an oxide film that remains after pickling, and the surface layer portion is more insoluble than the inner layer. Antibacterial properties may be significantly reduced. In addition, the antibacterial element (Ag) may disappear from the surface layer during annealing, and a region having a low antibacterial element concentration may be formed on the surface layer. After annealing, descaling is performed by pickling or the like to dissolve the surface layer. Even if gold is exposed, there is a problem that the concentration of the antibacterial element does not recover and sufficient antibacterial properties may not be obtained.

[0009]

Even when the base material has antibacterial properties, the antibacterial components on the surface layer are rubbed off or removed when the final product is formed by polishing, molding or the like. In some cases, the antibacterial property of the final product may disappear or the antibacterial property of the surface layer may react with the component contained in the abrasive or other surface treatment agent and react with the antibacterial component of the surface layer. There was a problem that the antibacterial properties of the product did not appear.

[0010] Even when the base material does not have antibacterial properties, it may be desired to impart antibacterial properties to the final product. This demand is a strong demand that is potentially present not only in stainless steel products but also in general metal products used for applications requiring antibacterial properties. An object of the present invention is to advantageously solve the above-mentioned problems of the prior art and to propose a method for producing a metal product having excellent antibacterial properties, which can impart antibacterial properties to a metal product, particularly a finished product. And

[0011]

Means for Solving the Problems The present inventors have intensively studied a method for easily imparting antibacterial properties to a metal product, particularly a finished stainless steel product. As a result, by immersing the metal product in an aqueous solution containing silver ions, not only when the base material of the metal product retains antibacterial properties, but also when the Was found to adhere to the metal product having high antibacterial properties.

The present invention has been completed based on the above findings. That is, the present invention provides a metal product, silver ions: 0.0001~1.0mol / l, nitrate: nitric comprising 1-200 g / l
Ru manufacturing method der metal products with excellent antimicrobial, characterized by immersion in an aqueous acid solution. In addition, the present onset Ming, metal products
Containing silver ions: 0.0001 to 1.0 mol / l, sodium hydroxide
Gold with excellent antibacterial properties, characterized by being immersed in an alkaline aqueous solution adjusted to pH 8.0 or more as a pH adjuster.
It is a method of manufacturing a product of the genus.

In the present invention, the metal product is preferably a stainless steel product processed into a final shape, and in the present invention, the metal product has an Ag content of 0.001 to 0.001.
0.10wt% or V: 0.001 ~ 0.30wt%
It is preferably a stainless steel product processed into a final shape containing Further, the present invention contains 0.001 to 0.10 wt% of Ag, or
Further processed into the final shape containing V: 0.001-0.30 wt%
Stainless steel products, silver ion: 0.0001 ~ 1.0mol / l
Excellent antibacterial properties characterized by being immersed in an aqueous solution containing
This is a method for manufacturing a metal product.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The object of the present invention is a metal product used for applications requiring antibacterial properties, and is a metal product processed into a final shape. As the metal, any of aluminum, titanium, steel and the like are preferable, and among them, stainless steel, particularly stainless steel containing Ag or the like is preferable. Metal products processed into the final shape have various deposits near the surface, even if the base material has antibacterial properties,
The reality is that antibacterial properties cannot be stably exhibited.

Therefore, in the present invention, the metal product is immersed in an aqueous solution containing silver ions: 0.0001 to 1.0 mol / l to provide a good antibacterial property stably. The antibacterial carrier in the present invention is a minute amount of silver ions contained in the solution. In order to stably develop antibacterial properties, it is important to control silver ions to adhere uniformly and at an appropriate rate to metal products. For this purpose, silver ion concentration in an aqueous solution to be immersed, It is necessary to adjust the pH of the aqueous solution, the form of silver ions present, and the distribution of silver ions in the solution.

The metal products silver ions: When immersed in an aqueous solution containing 0.0001~1.0mol / l, Ag ← Ag + + e - reaction proceeds in, Ag is deposited adheres very short time the metal product surface. Thereby, good antibacterial properties can be imparted without impairing the surface gloss and corrosion resistance. If the silver ion concentration in the aqueous solution is less than 0.0001 mol / l, the deposition of Ag on the surface of the immersed metal product is small, and the antibacterial property of the metal product is not sufficiently improved. The higher the silver ion concentration in the aqueous solution, the greater the amount of Ag that adheres to the surface of the metal product and the higher the antibacterial property.However, even if the content exceeds 1.0 mol / l, the antibacterial property becomes higher. No improvement is obtained. In addition, excessive silver ions cause a large amount of Ag or Ag compounds (Ag ₂ O) to precipitate and adhere to the metal product surface, and the adhered Ag reacts with S in the atmosphere when the product is used, resulting in a color tone on the product surface. To darken,
The passivation of the surface layer is hindered, and the Ag compound deposited and adhered to the surface also hinders the passive transformation of the surface layer, deteriorating the corrosion resistance. For this reason, in the present invention, the silver ion concentration in the aqueous solution is limited to the range of 0.0001 to 1.0 mol / l. Preferably, it is 0.001 to 0.10 mol / l. Further, the Ag ion added to the solution in the present invention is not problematic in any form, and it is not necessary to particularly limit, but does not react with the solution.
AgNO ₃ and Ag ₂ O are preferred.

As the aqueous solution used in the present invention, an acidic aqueous solution and an alkaline aqueous solution having a pH of 8.0 or more are all suitable. As an acidic aqueous solution, silver ions: 0.0001 to 1.0 mol / l
It is preferable to use a nitric acid aqueous solution containing nitric acid: 1 to 200 g / l. Silver ion for metal products: 0.0001-1.0mol
When immersed in a nitric acid solution containing ^{/ l, Ag ← Ag + +} e - reaction proceeds in a very short time Ag precipitates adhere to the surface of the steel sheet. Thereby, the antibacterial property can be improved without impairing the gloss and corrosion resistance of the surface. The silver ion concentration in the nitric acid aqueous solution is more preferably 0.001 to 0.1 m
ol / l.

On the other hand, if the nitric acid concentration in the aqueous nitric acid solution is less than 1 g / l, the conductivity of the aqueous solution deteriorates, and it becomes difficult for Ag to precipitate and adhere to the metal product surface in a short time. On the other hand, generation of the NO _X exceeds 200 g / l becomes prominent, so hinder deposition adhesion to metal products surface of the silver ions. Therefore, the concentration of nitric acid in the aqueous solution is preferably limited to the range of 1 to 200 g / l. In order to shorten the processing time, the amount is more preferably 30 to 150 g / l from the viewpoint of the reaction rate.

On the other hand, when a metal product is immersed in an alkaline aqueous solution containing at least 0.0001 mol / l of silver ions and having a pH of 8.0 or more, Ag ₂ O precipitates and adheres to the surface in addition to the deposition of Ag particles on the surface. However, the antibacterial properties can be significantly improved without impairing the gloss and corrosion resistance of the surface layer. Ag ₂ O has a high solubility in water and is more effective in improving antibacterial properties than Ag particles alone. On the other hand, if silver ions are contained in excess of 1.0 mol / l, no further improvement in antibacterial properties can be obtained, and when the metal product is made of stainless steel, the passivation of the surface layer is prevented and unnecessarily. Ag ₂ O adheres and deteriorates corrosion resistance. For this reason, silver ions in an alkaline aqueous solution having a pH of 8.0 or more are preferably limited to 0.0001 to 1.0 mol / l. More preferably, it is 0.001 to 0.10 mol / l.

According to the study of the present inventors, there is a pH range of a solution suitable for the deposition and deposition of Ag ₂ O. When the pH is less than 8.0, Ag ₂ O does not precipitate and adhere to the surface in a short time, and the treatment time for imparting antibacterial properties becomes long. Therefore, the pH of the alkaline aqueous solution is preferably set to 8.0 or more. The pH is more preferably from 11.0 to 14.0. When the pH exceeds 14.0,
Almost no deposition of Ag ₂ O is observed.

It is preferable to use sodium hydroxide (NaOH) as the pH adjuster for the aqueous alkali solution. Sodium hydroxide (NaOH) is unlikely to prevent passivation of the surface of stainless steel materials, especially stainless steel materials containing Ag for imparting antibacterial properties. By containing sodium hydroxide in the range of 0.004 to 40 g / l in the alkaline aqueous solution, the pH of the aqueous solution becomes a predetermined pH range and the state of deposition and adhesion of Ag becomes the most desirable state. For this reason, in the present invention, it is preferable that the concentration of sodium hydroxide contained in the aqueous alkali solution as the pH adjuster is 0.004 to 40 g / l. In addition, it is more preferably 0.04 to 4.0 g / l.

In the present invention, potassium hydroxide (KOH) or calcium hydroxide (Ca (OH) ₂ ) may be used as a pH adjuster instead of sodium hydroxide. Further, these may be mixed. When immersing a metal product using the aqueous solution having the above-described composition, the temperature of the aqueous solution and the immersion time can be appropriately adjusted depending on the required degree of antibacterial activity, the length of the process, and the like. do not do. In addition, from the viewpoint of the processing speed, the liquid temperature is 35 to 55 ° C., and the immersion time is 10 to 120 s.
ec is desirable, but not limited to this.

In the present invention, the metal product used is
Good antibacterial properties can be imparted without being limited by the type, manufacturing method, and processing method. In particular, the effect of the present invention can be effectively exerted when applied to a finished stainless steel product, which is often applied to a life-related product having a high antimicrobial requirement. Further, among the final processed stainless steel products, by applying to the final processed product of stainless steel containing Ag and imparting antibacterial property, deterioration of the antibacterial property of the surface layer due to processing can be compensated.

[0024] As the finished stainless steel product suitably used in the present invention, any of ferritic stainless steel, austenitic stainless steel and martensitic stainless steel can be suitably used. The chemical composition of ferritic stainless steel is as follows: C: 0.0001 to 0.1 wt%, Si: 1.0 wt% or less, Mn: 2.0 wt% or less, P: 0.1 wt% or less, S: 0.1 wt%.
%, Cr: 8 to 50% by weight, N: 0.1% by weight or less, with the balance being Fe and unavoidable impurities. In addition,
Al: 0.3 wt% or less, Ni: 1.0 wt% or less, Mo: 5.0 wt% or less, Ti: 1.0 wt% or less, Nb: 1.0 wt% or less, Zr: 1.0 wt%
%, Cu: 1.0 wt% or less, W: 0.3 wt% or less, Co: 0.0
01 to 0.5 wt%, B: one or more of 0.01 wt% or less may be contained.

The chemical composition of the austenitic stainless steel is as follows: C: 0.001 to 0.1 wt%, Si: 2.0 wt% or less, Mn: 2.
0 wt% or less, P: 0.1 wt% or less, S: 0.1 wt% or less, C
r: 10 to 35 wt%, Ni: 6 to 15 wt%, N: 0.001 to 0.1 wt
%, With the balance being Fe and unavoidable impurities. In addition, Al: 0.3 wt% or less, Mo: 3.0 wt% or less, T
i: 1.0 wt% or less, Nb: 1.0 wt% or less, Zr: 1.0 wt% or less, Cu: 1.0 wt% or less, W: 0.3 wt% or less, Co: 0.001
0.5 wt%, B: one or more of 0.01 wt% or less.

The chemical composition of martensitic stainless steel is as follows: C: 0.001 to 1.0 wt%, Si: 1.0 wt% or less, Mn: 2.
0 wt% or less, P: 0.1 wt% or less, S: 0.1 wt% or less, C
r: 8 to 19 wt%, N: 0.001 to 0.1 wt%, the balance Fe
And it is preferable to use unavoidable impurities. In addition, Al:
1.5 wt% or less, Ni: 3.0 wt% or less, Mo: 3.0 wt% or less,
Ti: 1.0 wt% or less, Nb: 1.0 wt% or less, Zr: 1.0 wt% or less, Cu: 1.0 wt% or less, W: 0.3 wt% or less, Co: 0.001
0.5 wt%, B: one or more of 0.01 wt% or less.

The stainless steel finished product suitably used in the present invention preferably has the chemical composition of various stainless steels in the above-mentioned generally known ranges, and further has an Ag content of 0.001 to impart antibacterial properties to the product base material. A cold-rolled and annealed stainless steel cold-rolled steel sheet containing -0.10 wt%, or V: 0.001 -0.30 wt%, and further processed by press forming or the like to form a final shape. Product.

Next, of the composition of the finished stainless steel product suitably used in the present invention, the preferred ranges of the Ag and V contents will be described. Ag: 0.001 to 0.10 wt% Ag is an element that has an effect of suppressing bacterial growth and enhances antibacterial properties. These effects are observed when added at 0.001 wt% or more, but when added over 0.10 wt%, they have the effect of increasing antibacterial properties. However, corrosion resistance is degraded, surface defects during hot rolling are increased, and the cost is increased. Since a large amount of Ag is added in a large amount, the cost is increased, which is economically disadvantageous. When the amount of Ag in the steel exceeds 0.10 wt%, the amount of Ag oxide in the surface layer increases. The oxide affects the corrosion resistance. If the amount of Ag oxide in the surface layer increases, the passive film formed by pickling does not exist stably, and the corrosion resistance deteriorates. In addition, more preferably, it is 0.01 wt% or more and 0.05 wt% or less.

V: 0.001 to 0.30 wt% V is 0.001 to 0.30 wt% in addition to Ag in the above range.
%. V has the effect of remarkably improving the tendency of Ag compounds such as Ag particles, Ag oxides and Ag sulfides to be unevenly distributed in the center of the plate thickness, and uniformly dispersing Ag particles and Ag compounds in steel. Is an element effective for improving the antibacterial property of steel. By containing V in an amount of 0.001 wt% or more, uniform antibacterial properties of the steel surface can be achieved. On the other hand, if added in excess of 0.30 wt%, the workability of the steel material tends to decrease.
More preferably, it is 0.001 to 0.10 wt%, and still more preferably, 0.010 to 0.025 wt%.

[0030]

(Example 1) A stainless steel cold-rolled steel sheet having the chemical composition shown in Table 1 was subjected to bright annealing in a reducing atmosphere or a C gas burning atmosphere (oxygen 3%, carbon dioxide 7%, steam 20%, Annealing treatment in nitrogen)
A finished steel sheet or a 2B finished steel sheet was used. By using these finished steel plates, a processed stainless steel product (spoon, lunch box, plate) of a predetermined shape was produced by press working. These processed products were further subjected to # 400 polishing to give finished products having metallic luster. For comparison, some products were finished without polishing. These final products were immersed in an aqueous nitric acid solution under the conditions shown in Table 2. Thereafter, the product was washed.

In order to further evaluate the durability and durability of the steel sheet, the surface was rubbed reciprocally 20 times with # 400 abrasive paper, and further subjected to an antibacterial test. The outline of the test method of each test is described below. (1) Antibacterial property test The antibacterial property was evaluated as follows.

The test body (test area 2500 mm ² ) is washed and degreased with absorbent cotton containing 99.5% ethanol. E. coli is dispersed in a 1/500 NB solution. (The number of bacteria is
It was adjusted to 2.5 × 10 ⁵ cfu / sheet. The 1/500 NB solution is a solution obtained by diluting a normal Bion medium (NB) 500 times with sterilized purified water. Ordinary Bion medium (NB) is meat extract 5.0g, sodium chloride 5.0g, peptone 10.0g, purified water
1.000ml, pH: 7.0 ± 0.2 Inoculate the test solution (3 each) with the bacterial solution at a rate of 0.4 ml / 25 cm ² .

A polyethylene film is put on the surface of the test piece. Store at a temperature of 35 ° C ± 1.0 ° C and RH 90% or more for 24 hours. (RH: relative temperature) The number of viable cells is measured by an agar plate method (35 ± 1.0 ° C., 48 hours). The antibacterial activity was evaluated by a sterilization rate defined by the following equation.

Sterile reduction rate (%) = (number of bacteria of control−number of bacteria after test) / (number of bacteria of control) × 100 The number of bacteria of the control is the number of bacteria after the antibacterial test of the stainless steel material not subjected to the antibacterial treatment. It refers to the viable count. The number of bacteria after the test is the number of viable bacteria measured. (2) Corrosion resistance test The corrosion resistance was evaluated by a salt-dry / wet combined cycle test.

A test piece was sprayed with a 5.0% aqueous NaCl solution (temperature: 35 ° C.) for 0.5 hours for 0.5 hour, and then dried in a dry atmosphere at a humidity of 40% or less and a temperature of 60 ° C.
Hold for hours. Humidity: 95% or more, temperature: Keep in a humid atmosphere of 40 ° C for 1.0 hour. After a plurality of cycles (5 to 30 cycles) set for each steel type were repeated as one cycle, the rusting area ratio (%) of the test piece surface was measured.

Table 2 shows the results.

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

[Table 3]

[0040]

[Table 4]

[0041]

[Table 5]

Each of the examples of the present invention shows excellent antibacterial properties and also has excellent corrosion resistance. Even when the base material does not exhibit antibacterial properties, the final product exhibits antibacterial properties by applying the production method of the present invention. Furthermore, when the base material is a stainless steel containing Ag, the durability and durability of the antibacterial property are maintained, and the antibacterial property of the outermost surface of the final product can be further stabilized. In addition, it exhibits better antibacterial properties than the base material. Further, the production method of the present invention does not deteriorate the corrosion resistance inherent in stainless steel. The above results can be confirmed regardless of the type of stainless steel.

On the other hand, Comparative Examples outside the scope of the present invention have deteriorated antibacterial properties or deteriorated corrosion resistance. (Example 2) A stainless steel cold-rolled steel sheet having the chemical composition shown in Table 1 was subjected to the same treatment as in Example 1 by using a BA-finished steel sheet or a 2B-finished steel sheet to have a predetermined shape by press working. Made stainless steel products (spoon, lunch box, plate). These processed products were further subjected to # 400 polishing to give finished products having metallic luster. For comparison, some products were finished without polishing. These final products were immersed in an aqueous alkaline solution under the conditions shown in Table 3. Thereafter, the product was washed.

Further, in order to further evaluate the persistence and durability of these steel sheets, the surface was rubbed with # 400 abrasive paper 20 times in the same manner as in Example 1, and then the antibacterial test was carried out. Was carried out. Table 3 shows the results.

[0045]

[Table 6]

[0046]

[Table 7]

[0047]

[Table 8]

Each of the examples of the present invention in which the final product was immersed in an aqueous alkaline solution containing silver ions within the scope of the present invention exhibited excellent antibacterial properties. Further, the examples of the present invention have a low rusting area ratio and are excellent in corrosion resistance. Further, even when the base material does not exhibit antibacterial properties, the final product will exhibit antibacterial properties by applying the production method of the present invention. Furthermore, when using stainless steel containing Ag in the base material,
The antibacterial property and durability are high, and the antibacterial property of the outermost surface of the final product can be more stably exhibited, and the antibacterial property is superior to that of the base material. Further, the production method of the present invention does not deteriorate the corrosion resistance inherent in stainless steel. The above results, regardless of the type of stainless steel,
You can check.

On the other hand, the comparative examples outside the scope of the present invention have deteriorated antibacterial properties or deteriorated corrosion resistance.
As for the antibacterial property, a sterilization rate of 99.0% or more was regarded as acceptable. As for the corrosion resistance, a sterilization rate of 99.0% or more was satisfied, and a rusting area rate of 15% or less was accepted.

[0050]

According to the present invention, a metal product having excellent antibacterial properties can be provided irrespective of the presence or absence of the antibacterial properties of the base material, and industrially remarkable effects can be obtained. In particular, ferrite, austenitic, and martensitic stainless steels can exhibit sufficient antibacterial properties, and can be given a sufficient antibacterial property. In addition, it can be easily applied to final processed products in which the antibacterial property of the surface layer is apt to decrease, and it can be expected that the antibacterial property is improved. In particular, members where hygiene is important, for example,
Antibacterial properties can be easily imparted to stainless steel finished products, which are used in household goods or in applications where bacteria can easily grow in wet environments such as kitchens and bathtubs, regardless of whether the base material has antibacterial properties. There is.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shoji Ishikura 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Engineering Co., Ltd. (72) Noriko Makiishi 1-kawasaki, Chuo-ku, Chiba-shi, Chiba (56) References JP-A-10-15041 (JP, A) JP-A-7-18208 (JP, A) JP-A-2000-11584 (JP, A) (58) Fields investigated Int.Cl. ⁷ , DB name) C23C 30/00 C23C 26/00

Claims (5)

(57) [Claims] A metal product is prepared by adding silver ions: 0.0001 to 1.0 mol.
/ l, nitrate: 1-200 g / l method for producing a metal product having excellent antibacterial property you characterized that you immersed in a nitric acid aqueous solution containing. 2. The method according to claim 1, wherein the metal product is silver ion: 0.0001 to 1.0 mol
/ l, sodium hydroxide as pH adjuster, pH 8.0
Method for producing a superior metal products for anti fungal you <br/> characterized that you immersed in an alkaline aqueous solution adjusted to above. 3. The product according to claim 1, wherein the metal product is a stainless steel processed product processed into a final shape.
Or the method for producing a metal product excellent in antibacterial properties according to item 2 . 4. The method according to claim 1, wherein the metal product is Ag: 0.001 to 0.10 wt%.
3. The method for producing a metal product having excellent antibacterial properties according to claim 1 or 2 , wherein the product is a stainless steel processed product processed into a final shape containing V. 0.001 to 0.30 wt%. 5. A stainless steel processed product having a final shape containing 0.001 to 0.10 wt% of Ag : or 0.001 to 0.30 wt% of V: 0.0001 to 1.0 mol of silver ions.
method for producing a metal product having excellent antibacterial property you characterized by immersing in an aqueous solution containing / l.