JP3513581B2 - Nickel-chromium plating film having antibacterial properties and plating method - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to nickel-chromium plating having antibacterial properties.

[0002]

2. Description of the Related Art Faucet metal fittings and their accessories and accessories used around water are improved in aesthetic appearance and have a higher surface hardness to prevent scratches and corrosion resistance to prevent rusting. Therefore, plating is usually applied.

The most commonly used for water products is nickel-chromium plating, which has excellent corrosion resistance. However, since nickel-chromium plating has no antibacterial property, it often happens that molds and other bacteria propagate on the product surface.

Although silver plating and copper plating have antibacterial properties, they are inferior in surface hardness and corrosion resistance to nickel-chromium plating, so that they are easily scratched and may be corroded. Therefore, it is not generally applied to water products and is expensive.

Therefore, by providing an antibacterial substance in the plating film, it is possible to impart antibacterial properties to the plating.
Previously proposed.

Japanese Patent Application No. 5-145466 (Japanese Unexamined Patent Publication No. 6-1
Japanese Patent No. 0191: hereinafter referred to as Document a) describes that an inorganic antibacterial agent particle is dispersed in a nickel plating layer formed on the surface of a base material to give an antibacterial effect.

Further, Japanese Patent Application No. 6-19408 (Japanese Patent Application Laid-Open No. 7-196408)
No. 228999 gazette: hereinafter referred to as Document b), in addition to the presence of an antibacterial and antifungal substance in the nickel plating layer, the surface of the substrate is preliminarily nickel-plated, and the surface is antibacterial and antifungal. It describes a method of obtaining a nickel-chromium plating film having antibacterial and antifungal properties by performing a plating treatment with a chromium plating solution in which the above substance is dispersed and suspended.

[0008]

The technique described in Document a merely covers the surface of the base material with a nickel plating layer in which an antibacterial agent is dispersed, and has sufficient corrosion resistance as compared with nickel-chromium plating. I can't. Antibacterial properties are especially required in the kitchen, washroom, toilet, bathroom, etc., where nickel-
It is desirable to use chrome-plated faucet fittings.
Therefore, the technique of Document a is not practical when it is considered to be applied to products around water.

On the other hand, Document b describes that an antibacterial and antifungal substance is dispersed in a chromium plating layer to obtain an antibacterial nickel-chromium plating film. According to the description of the example of Document b, the nickel-plated base material is plated with a chrome plating solution in which a powder of a substance containing a silver compound is dispersed, so that the surface of the nickel-plated layer has an antibacterial property. A method of forming a chromium plating layer in which a mildewproof substance is present is adopted.

However, the deposition rate of chromium plating is extremely slow, which is only about 1/15 of the deposition rate of nickel plating. Therefore, it is very difficult to coprecipitate the antibacterial agent particles dispersed in the plating solution with the chromium metal and take them into the plating layer, and it is necessary to make the antibacterial agent particles not exist in the chromium plating layer in a small amount. It is impossible in reality. Even if the inorganic antibacterial agent is taken into the plating layer,
Its amount is so small that it cannot provide the necessary antibacterial properties. That is, the chromium plating method of Document b in which the antibacterial agent is present in the chromium plating layer on the product surface by dispersing the antibacterial agent in the chromium plating solution is
Poor feasibility.

Moreover, in order to uniformly disperse the powder in the plating layer, it is necessary to keep the plating solution in a sufficiently agitated state, but it is not usual to agitate the chromium plating bath. Because of this, new equipment is required to implement this. Also in this respect, the technique of dispersing the antibacterial substance in the chromium plating layer described in Document b was difficult to implement.

[0012]

The present invention provides means for realizing nickel-chromium plating having antibacterial properties, which is characterized in that an inorganic antibacterial agent is dispersed. Nickel with a chromium plating layer formed on the surface of the nickel plating layer in which the particles of the inorganic antibacterial agent are dispersed by performing the nickel plating treatment on the surface of the base material while sufficiently stirring the nickel plating solution and then performing the chromium plating treatment. -To obtain a chrome-plated coating.

The particle size of the inorganic antibacterial agent particles dispersed in the nickel plating solution is preferably in the range of 0.1 to 20 μm, and the addition amount of the inorganic antibacterial agent particles is preferably in the range of 0.1 to 50 g / l. , The thickness of the chrome plating layer is 0.1 to 1.0
It is desirable to set it in the range of μm.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION In carrying out the present invention,
Although dedicated plating equipment may be newly built, it is possible to use conventional equipment for nickel-chromium plating. There is no particular limitation on the plating target, and all products that are plated with nickel-chromium can be used in kitchens, washrooms, bathrooms, etc., such as faucet fittings and their accessories and accessories around water.
It is particularly suitable to implement the equipment used in a toilet or the like.

The type of plating method is appropriately selected according to the material of the base material. Generally, the electroplating method is used for metallic base materials such as iron, copper, and copper alloys, and for non-metallic base materials such as plastic or resin-coated base materials,
First, a method may be adopted in which electroconductivity is applied by electroless plating and then electroplating is performed.

The outline of the steps for carrying out the present invention is as follows. When the base material to be plated is made of a conductive material such as metal, first, a nickel plating layer is formed on the surface of the base material by electroplating with a nickel plating solution in which an inorganic antibacterial agent is dispersed.

As the inorganic antibacterial agent to be mixed in the nickel plating solution, for example, a metal having antibacterial properties such as silver and copper supported on zeolite particles, zirconium phosphate particles, composite glass particles and the like is used.

The particle size of the inorganic antibacterial agent particles is 0.1 to 20 μm.
It is preferably set in the range of m. If it is less than 0.1 μm, the antibacterial agent particles may aggregate and it may be difficult to disperse them in the plating solution. Particle size is 0.1-10 μm
In the range, the plating surface becomes almost smooth, and a so-called bright glossy surface is obtained. When the particle size is in the range of 10 to 20 μm, the plating surface becomes rather rough and a satin matte surface can be formed. If the particle size exceeds 20 μm, the plating surface becomes rough and the appearance may be impaired.

It seems appropriate that the amount of the inorganic antibacterial agent mixed with the nickel plating solution is in the range of 0.1 to 50 g / l. If it is less than 0.1 g, effective antibacterial properties may not be obtained. The range of the addition amount of 0.1 to 20 g / l is a range where a usual glossy surface (bright surface) is formed. When the amount is in the range of 20 to 50 g / l, the plating surface becomes slightly rough and becomes a satin matte surface. 50 g / l
If it exceeds, the gloss of the plating surface may be unnecessarily reduced.

During the plating process, the nickel plating solution is sufficiently stirred in order to maintain a uniform dispersed state of the mixed inorganic antibacterial agent. The stirring means may be a method of blowing bubbles from a blower into the plating bath or a method of stirring with a screw.

If the particle size of the inorganic antibacterial agent is small, it may cause aggregation in the plating solution. Therefore, a dispersant may be added if necessary. Generally, a ceramic particle such as an inorganic antibacterial agent is negatively charged in water, and therefore a cationic surfactant may be added as a dispersant.

When the nickel plating solution in which the inorganic antibacterial agent is dispersed as described above is subjected to the plating treatment while being sufficiently stirred, nickel is deposited on the surface of the base material and, at the same time, the particles of the inorganic antibacterial agent are taken into the final product. Then, a nickel plating layer in which the inorganic antibacterial agent is dispersed is formed.

Next, the surface of the nickel plating layer is plated with chromium by a known method to obtain the desired nickel-chromium plating film. The thickness of the chromium plating layer is preferably in the range of 0.1 to 1.0 μm. If the layer thickness is less than 0.1 μm, it becomes difficult to obtain the required surface hardness and corrosion resistance, and if it exceeds 1.0 μm, the antibacterial property may be impaired.

As mentioned above, references a and b describe nickel plating in which an antibacterial substance is dispersed in a plating layer. However, further chromium plating has not been conventionally performed on the nickel plating layer. This is because it has been conventionally considered that even if the nickel plating layer has antibacterial properties, effective antibacterial properties cannot be obtained because the antibacterial substance is coated when the surface of the nickel plating layer is plated with chromium.

However, the present inventors have obtained the finding that the inorganic antibacterial agent can be exposed on the surface if the thickness of the chromium plating layer is set to be appropriately small, and the present invention is based on the finding. Is the one that led to the idea. That is, since the inorganic antibacterial agent has low conductivity, as shown in the drawing, in the portion where the inorganic antibacterial agent is exposed on the surface of the nickel plating layer, the precipitation of chromium is suppressed, and the inorganic antibacterial agent is distributed in various places on the surface of the chromium plating layer. Exposed. As a result, a nickel-chromium plating film with the surface of the inorganic antibacterial agent formed is formed, which is conventionally considered difficult.
It is now possible to add antibacterial properties to chrome plating.

[0026]

【Example】

[First Embodiment] In this embodiment, as shown in FIG. 1, two nickel plating layers constituting a nickel-chromium plating film are formed.
It has a layered structure in which the inorganic antibacterial agent is dispersed only in the nickel plating layer on the surface side in contact with the chromium plating layer. In the procedure for forming the plating film having such a structure, first, the surface of the brass base material is subjected to ordinary bright nickel plating by electroplating to form an inner nickel plating layer. The composition of the nickel plating solution at this time was nickel sulfate hexahydrate 2
50 g / l, nickel chloride hexahydrate 55 g / l, boric acid 35 g / l, saccharin 1.2 g / l, butynediol 0.2 g / l, sodium lauryl sulfate 0.2 g / l. The plating conditions are: current value = 4 A / dm ² , temperature = 55 ° C., pH = 4.3, and plating layer thickness is 10 μm.
And

Next, plating is performed with a nickel plating solution containing an inorganic antibacterial agent to form a surface side nickel plating layer. The composition of the nickel plating solution containing an inorganic antibacterial agent is the same as the nickel plating solution except that the zeolite-silver antibacterial agent (particle size =
3 μm) added at 5 g / l is used. The plating conditions are: current value = 4 A / dm ² , temperature = 55 ° C., pH =
In 4.3, the thickness of the plating layer is 2 μm. Stirring of the plating solution during the plating process is performed by blowing bubbles into the plating bath from a blower, and the stirring condition is 1 m area of the plating solution.
Set to 300 liters / minute per ²

After completion of the nickel plating treatment,
Apply chrome plating. The composition of the chrome plating solution was 250 g / l of chromic anhydride and 2.5 g / l of sulfuric acid, the treatment conditions were a current value of 10 A / dm ² , a temperature of 40 ° C., and a plating layer thickness of 0.3 to 0. 5 μm.

As a result of the above processing steps, a nickel-chromium plating film having a structure as shown in FIG. 1 is obtained. The nickel-chromium plating film had antibacterial properties, and the surface gloss and color tone were equivalent to those of ordinary nickel-chromium plating.

When the antibacterial agent particles are dispersed in the nickel plating layer, the smoothness of the plating surface may be deteriorated. However, as in this example, the nickel plating layer has a two-layer structure and the antibacterial agent is applied only to the surface side. The presence of the agent can suppress the decrease in the smoothness of the plating surface. Moreover,
By adjusting the thickness of the inner nickel plating layer that is in contact with the base material, it is easy to secure the layer thickness necessary for exhibiting corrosion resistance. Further, in this embodiment, since the antibacterial agent is present only in the surface side nickel plating layer, there is an advantage that the amount used can be saved.

[Second Embodiment] In the present embodiment, the nickel-plated layer of the nickel-chromium plated coating is composed of one layer as shown in FIG. The procedure of the plating treatment will be described. First, the electroplating method is used to perform nickel plating on the surface of the bronze substrate with a plating solution containing an antibacterial agent. The composition of the plating solution was nickel sulfate hexahydrate 250 g / l, nickel chloride hexahydrate 55 g / l, boric acid 35 g / l, saccharin 1.2 g / l, butynediol 0.2 g / l, sodium lauryl sulfate 0. 0.2 g / l, and as an inorganic antibacterial agent, zeolite-silver antibacterial agent 5 g / l (particle size = 3
μm) is added. The nickel plating treatment condition is current value =
The thickness of the plating layer is 10 μm at 4 A / dm ² , temperature = 55 ° C., pH = 4.3. Stirring of the plating bath during the plating treatment is performed by blowing air bubbles into the plating bath from a blower, and the stirring condition is 300 liters / min per 1 m ² area of the plating solution.

After completion of the nickel plating treatment,
Apply chrome plating. The composition of the chrome plating solution is chromic anhydride 250 g / l, sodium silicofluoride 5 g /
1, sulfuric acid 1 g / l, and the treatment condition was a current value of 10 A / d
m ^{2 at} a temperature of 40 ° C., the thickness of the plating layer was 0.3 to 0.
5 μm.

The nickel-chromium plating film obtained in this example also has antibacterial properties, and the surface gloss and color tone are equivalent to those of ordinary nickel-chromium plating. In this embodiment, the number of plating treatments is one less than that in the first embodiment.

[Third Embodiment] In the first and second embodiments, the inorganic antibacterial agent added to the plating solution is zirconium phosphate-silver antibacterial agent 2 g / l (particle size = 0.5 μm).
m). The zirconium phosphate-silver-based antibacterial agent used here has excellent antibacterial activity, and since it has a large specific surface area due to its small particle size, it can be added in a smaller amount than the zeolite-silver-based antibacterial agent. it can.

However, since the zirconium phosphate-silver antibacterial agent of this example has a small particle size, it may cause aggregation in the plating solution. Therefore, in order to prevent aggregation of the antibacterial agent, a dispersant is added if necessary. Generally, zirconium phosphate-
Since ceramic particles such as a silver-based antibacterial agent are negatively charged in water, it is preferable to add a cationic surfactant as a dispersant.

The use of the dispersant is not essential and is appropriately selected depending on the situation. If the dispersibility of the antibacterial agent is good, it is not necessary to add a dispersant, and it may be used when an antibacterial agent which is difficult to disperse as it is is added to the plating solution. The kind of the dispersant to be added is not limited to the cationic surfactant, and an optimum one may be selected according to the kind of the antibacterial agent and the plating conditions.

[Fourth Embodiment] A synthetic resin substrate or a substrate whose surface is coated with a synthetic resin can be subjected to a plating treatment by an electroless plating method. Even if direct nickel plating is performed with a plating solution containing an inorganic antibacterial agent, the adhesion of the plated coating to the substrate may not be secured. The document b describes that a nickel plating film containing silver oxide-containing powder is formed on the surface of a plastic substrate by using an electroless plating method. However, this method is based on the reason described above. Not practical.

Therefore, when applying the present invention to a non-metallic substrate, it is preferable to adopt the method described below. First, a thin nickel plating layer (thickness: about 0.5 μm) is formed on the surface of the base material by using an electroless plating method. This imparts conductivity to the surface of the base material. Next, this is energized in a copper sulfate solution to perform copper plating (thickness of about 1
0 μm).

Since the surface of the base material is covered with the copper plating film by the above processing, the subsequent processing can be handled in the same manner as the copper base product. That is, the first for the substrate after copper plating
According to the embodiment, after performing the usual bright nickel plating to form the inner nickel plating layer, the surface side nickel plating layer containing the inorganic antibacterial agent is formed, and then the surface can be subjected to the chromium plating treatment. Alternatively, the second
According to the embodiment, a nickel plating treatment containing an inorganic antibacterial agent is performed on the copper plating layer to form a nickel plating layer, and then a chromium plating treatment is performed.

For reference, FIG. 3 shows the plating film structure obtained by the fourth embodiment. (A) of the figure shows a nickel plating layer having a two-layer structure formed on a copper plating layer according to the first embodiment, and FIG. (B) shows only one nickel plating layer according to the second embodiment. Is formed.

[0041]

According to the present invention, nickel-chromium plating, which has been considered difficult in the past, can be provided with antibacterial properties, and further, it can be carried out by making a slight change to the conventional plating equipment. it can. Therefore, a high-value-added faucet fitting or the like having antibacterial properties can be provided at low cost.

[Brief description of drawings]

FIG. 1 is a drawing conceptually explaining a structure of a nickel-chromium plating film according to a first embodiment of the present invention.

FIG. 2 is a drawing conceptually explaining a structure of a nickel-chromium plating film according to a second embodiment of the present invention.

FIG. 3 is a drawing conceptually explaining a structure of a nickel-chromium plating film according to a fourth embodiment of the present invention.

Front page continued (58) Fields surveyed (Int.Cl. ⁷ , DB name) C25D 15/02 A01N 59/16

Claims (6)

(57) [Claims] 1. A nickel-chromium plating film having antibacterial properties, characterized in that a chromium plating layer is formed on the surface of a nickel plating layer in which particles of an inorganic antibacterial agent are dispersed. 2. The particle size of the inorganic antibacterial agent particles is from 0.1 to 20.
The nickel-chromium plating film having antibacterial properties according to claim 1, which is in the range of μm. 3. The amount of inorganic antibacterial agent particles added is from 0.1 to 5
The nickel-chromium plating film having antibacterial properties according to claim 1, which is in a range of 0 g / l. 4. The chromium plating layer has a thickness of 0.1 to 1.
The nickel-chromium plating film having antibacterial properties according to claim 1 or 2, which has a thickness of 0 μm. 5. The nickel-chromium plating film having antibacterial properties according to claim 2, wherein the inorganic antibacterial agent particles are exposed on the surface of the chromium plating layer. 6. A method for nickel-chromium plating having antibacterial properties, which comprises performing nickel plating treatment while stirring a nickel plating solution in which an inorganic antibacterial agent is dispersed, and then performing chromium plating treatment.