JPH1068100A - Antibacterial nickel-chromium plating film and plating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To impart an antibacterial property to an Ni-Cr plating by forming a Cr plating layer on the surface of an Ni plating layer in which an inorg. antibacterial agent is dispersed. SOLUTION: An Ni plating layer is firstly formed on the base material with an Ni plating soln. in which an inorg. antibacterial agent is dispersed. The antibacterial agent to be used is prepared by depositing a metal such as silver having an antibacterial property on a zeolite grain, etc. The diameter of the grain is controlled to 0.1-20μm, and 0.1-50g/L agent is added. A Cr plating is then applied on the surface of the Ni plating layer. The thickness of the Cr plating layer is controlled preferably to 0.1-10μm. Since the Cr plating layer is appropriately thinned in such a way, the antibacterial agent is exposed to the surface of the Ni plating layer. Namely, as the agent is low in conductivity, the deposition of Cr is suppressed at the spot where the agent is exposed to the surface of the Ni plating layer, the agent is exposed here and there, and the antibacterial property is exhibited.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Water faucet fittings and their accessories and accessories used around water have improved aesthetics, increased surface hardness to prevent scratches, and imparted corrosion resistance to prevent rust. Therefore, plating is usually performed.

[0003] The most commonly used for plumbing products is nickel-chromium plating which has excellent corrosion resistance. However, since nickel-chromium plating does not have antibacterial properties, molds and various germs often propagate on the product surface.

[0004] Silver plating and copper plating have antibacterial properties, but are inferior in surface hardness and corrosion resistance as compared with nickel-chromium plating, so they are easily damaged and may be corroded. Therefore, there is a drawback that the application to plumbing products is not common and is expensive.

[0005] Therefore, it is necessary to make the plating antibacterial by providing an antibacterial substance in the plating film.
Conventionally proposed.

Japanese Patent Application No. 5-145466 (Japanese Patent Application Laid-Open No. 6-1)
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 have an antibacterial effect.

Further, Japanese Patent Application No. 6-19408 (Japanese Patent Application Laid-Open No.
Japanese Patent No. 228999 (hereinafter referred to as "document b") discloses that in addition to the presence of a substance made of antibacterial and fungicide in the nickel plating layer, the surface of the substrate is preliminarily plated with nickel and the surface is made of antibacterial and fungicide. A method of obtaining a nickel-chromium plating film having antibacterial and antifungal properties by plating with a chromium plating solution in which the above substance is dispersed and suspended.

[0008]

According to the technique described in Document (a), the substrate surface is simply covered with a nickel plating layer in which an antibacterial agent is dispersed, and sufficient corrosion resistance is obtained as compared with nickel-chromium plating. I can't. Antibacterial properties are particularly required around kitchens, washrooms, toilets, bathrooms, and other places where water is frequently in contact with water.
It is desirable to use a chrome-plated faucet or the like.
Therefore, the technique of Document a is not practical when applied to a plumbing product.

On the other hand, Document b describes that a nickel-chromium plating film provided with antibacterial properties is obtained by dispersing an antibacterial and antifungal substance in a chromium plating layer. According to the description in the example of Document b, the surface of the nickel plating layer is treated with an antibacterial agent by plating a base material previously plated with nickel with a chromium plating solution in which a powder of a substance containing a silver compound is dispersed. A method of forming a chromium plating layer in which a fungicide is present is employed.

[0010] However, the deposition rate of chromium plating is extremely slow, and is only about one-fifteenth of the deposition rate of nickel plating. For this reason, it is very difficult for the antimicrobial agent particles dispersed in the plating solution to be co-deposited with the chromium metal and incorporated into the plating layer. In reality, it is impossible. Even if the inorganic antibacterial agent is taken into the plating layer,
The amount is very small and cannot provide the necessary antimicrobial properties. That is, the chromium plating method of Document b, in which an antibacterial agent is dispersed in a chromium plating solution so that the antibacterial agent particles are present in the chromium plating layer on the product surface,
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. However, the chromium plating bath is not usually agitated. Therefore, new equipment is required to implement this. Also in this respect, the technique for dispersing the antibacterial substance in the chromium plating layer described in Document b is difficult to implement.

[0012]

SUMMARY OF THE INVENTION The present invention provides a means capable of realizing nickel-chromium plating having antibacterial properties, which is characterized by dispersing an inorganic antibacterial agent. 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 subjecting the surface of the substrate to nickel plating with sufficient stirring of the nickel plating solution and then chromium plating -To obtain a chromium plating film.

Preferably, the particle size of the inorganic antibacterial agent dispersed in the nickel plating solution is in the range of 0.1 to 20 μm, and the amount of the inorganic antibacterial agent added is 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]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In carrying out the present invention,
Although a dedicated plating facility may be newly constructed, a conventional nickel-chromium plating facility can be used. There is no particular limitation on the plating target, and all products to which nickel-chromium plating is applied are used. However, kitchen faucets, toilets, bathrooms, bathroom faucets, their accessories, and water-related accessories are included.
Implementation on appliances used in toilets and the like is particularly preferred.

The type of plating method is appropriately selected according to the material of the substrate. Generally, an electroplating method is used for metallic substrates such as iron, copper, and copper alloys, and for nonmetallic substrates such as plastics or resin-coated substrates,
First, a method of providing electroconductivity by electroless plating and then electroplating may be employed.

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

As the inorganic antibacterial agent to be added to the nickel plating solution, for example, an antibacterial metal such as silver or copper supported on zeolite particles, zirconium phosphate particles, composite glass particles or the like is used.

The particle size of the inorganic antibacterial agent particles is 0.1 to 20 μm.
It is preferable to set it in the range of m. If the thickness is less than 0.1 μm, the antibacterial agent particles may aggregate and may be difficult to disperse in the plating solution. Particle size 0.1 to 10 μm
Within this range, the plating surface becomes substantially 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 slightly rough, and a satin matte surface can be formed. If the particle size exceeds 20 μm, the plating surface may be rough and the appearance may be impaired.

It is considered appropriate that the mixing amount of the inorganic antibacterial agent to the nickel plating solution is in the range of 0.1 to 50 g / l. If the amount 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 for forming a normal glossy surface (bright-like surface). When the content is in the range of 20 to 50 g / l, the plating surface becomes slightly rough and becomes a satin matte surface. 50g / 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 dispersion state of the mixed inorganic antibacterial agent. As the stirring means, a method of blowing air bubbles from a blower into a plating bath, a method of stirring with a screw, and the like can be considered.

If the particle size of the inorganic antibacterial agent is small, aggregation may occur in the plating solution. Therefore, a dispersant may be added as necessary. In general, since ceramic particles such as inorganic antibacterial agents are negatively charged in water, a cationic surfactant may be added as a dispersant.

As described above, when the plating treatment is performed while sufficiently stirring the nickel plating solution in which the inorganic antibacterial agent is dispersed, the nickel is precipitated on the surface of the substrate and the particles of the inorganic antibacterial agent are taken in at the same time. Then, a nickel plating layer in which an inorganic antibacterial agent is dispersed is formed.

Next, chromium plating is applied to the surface of the nickel plating layer by a known method to obtain a desired nickel-chromium plating film. It is desirable that the thickness of the chromium plating layer be 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 properties may be impaired.

As described above, documents 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 this nickel plating layer. This is because even if the nickel plating layer has an antibacterial property, it has conventionally been considered that an effective antibacterial property cannot be obtained because the antibacterial substance is covered by chromium plating on the surface.

However, the present inventors have obtained the knowledge that the inorganic antimicrobial agent can be exposed on the surface if the thickness of the chromium plating layer is set to be appropriately small. It is what led to inventing. That is, since the inorganic antibacterial agent has low conductivity, as shown in the drawing, at 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 located somewhere on the surface of the chromium plating layer. Exposed. As a result, a nickel-chromium plating film in which the inorganic antibacterial agent faces the surface is formed, and nickel-chromium plating, which has been conventionally considered to be difficult, is formed.
It has become feasible to impart antibacterial properties to chromium plating.

[0026]

【Example】

[First Embodiment] In this embodiment, as shown in FIG. 1, a nickel plating layer constituting a nickel-chromium plating film is formed by two layers.
It has a layer structure in which an inorganic antibacterial agent is dispersed only in the nickel plating layer on the surface side in contact with the chromium plating layer. The procedure for forming a plating film having such a structure is as follows. First, a normal bright nickel plating is applied to the surface of a brass substrate by an electroplating method to form an inner nickel plating layer. At this time, the composition of the nickel plating solution 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 were: current value = 4 A / dm ² , temperature = 55 ° C., pH = 4.3, and the thickness of the plating layer was 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 a nickel plating solution containing an inorganic antibacterial agent is such that a zeolite-silver antibacterial agent (particle size =
3 μm) is added at 5 g / l. The plating conditions were as follows: 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 air bubbles from a blower into the plating bath.
Set 300 l / min per ²

After completion of the nickel plating process,
Apply chrome plating. The composition of the chromium plating solution was chromic anhydride 250 g / l, sulfuric acid 2.5 g / l, and 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 reduced. However, as in this embodiment, the nickel plating layer has a two-layer structure and only the surface side has the antibacterial agent. The presence of the agent can suppress a decrease in the smoothness of the plating surface. Moreover,
By adjusting the thickness of the inner nickel plating layer in contact with the substrate, it is easy to secure a 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 this embodiment, the nickel plating layer of the nickel-chromium plating film is composed of one layer as shown in FIG. The procedure of the plating process will be described. First, nickel plating is performed on a bronze substrate surface with a plating solution containing an antibacterial agent by electroplating. 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 g / l. 0.2 g / l, and 5 g / l of zeolite-silver antibacterial agent (particle size = 3) as an inorganic antibacterial agent.
μm). Nickel plating processing conditions are current value =
4A / dm ² , temperature = 55 ° C., pH = 4.3, and the thickness of the plating layer is 10 μm. Stirring of the plating bath during the plating process is performed by blowing air bubbles from a blower into the plating bath, and the stirring condition is 300 liter / min per 1 m ² of the area of the plating solution.

After completion of the nickel plating process,
Apply chrome plating. The composition of the chromium plating solution is 250 g / l of chromic anhydride, 5 g of sodium silicate fluoride /
l, sulfuric acid 1 g / l, and the treatment conditions were a current value of 10 A / d
m ² , the temperature is 40 ° C., and the thickness of the plating layer is 0.3 to 0.1 mm.
5 μm.

The nickel-chromium plating film obtained in this embodiment also has antibacterial properties, and has the same surface gloss and color tone as ordinary nickel-chromium plating. In this embodiment, the number of times of the plating process is one less than in the first embodiment.

[Third Embodiment] In the first and second embodiments, the inorganic antibacterial agent to be added to the plating solution was 2 g / l of a zirconium phosphate-silver based antibacterial agent (particle size = 0.5 μm).
m). The zirconium phosphate-silver antibacterial agent used here has excellent antibacterial activity, and has a large specific surface area due to its small particle size. 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 as necessary. Generally, zirconium phosphate-
Since ceramic particles such as silver-based antibacterial agents are negatively charged in water, a cationic surfactant may be added as a dispersant.

The use of a 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 that is difficult to disperse as it is is added to the plating solution. Also, the type of dispersant to be added is not limited to the cationic surfactant, and an optimum one may be selected according to the type of antibacterial agent and plating conditions.

[Fourth Embodiment] Plating can be applied to a base made of a synthetic resin or a base whose surface is covered with a synthetic resin by an electroless plating method. Even if nickel plating is performed directly with a plating solution containing an inorganic antibacterial agent, the adhesion of the plating film to the substrate may not be ensured in some cases. The document b describes that a nickel plating film containing a silver oxide-containing powder is formed on the surface of a plastic substrate by using an electroless plating method. Not practical.

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

Since the surface of the substrate is covered with the copper plating film by the above-described processing, the subsequent processing can be handled in the same manner as a copper substrate product. In other words, for the substrate after copper plating, the first
After the inner nickel plating layer is formed by performing normal bright nickel plating according to the embodiment, a surface-side nickel plating layer containing an inorganic antibacterial agent is formed, and the surface thereof can be further subjected to chrome plating. Or the second
According to the embodiment, a nickel plating process including an inorganic antibacterial agent is performed on the copper plating layer to form a nickel plating layer, and then a chromium plating process is performed.

For reference, FIG. 3 shows a plating film structure obtained by the fourth embodiment. FIG. 7A shows a nickel plating layer having a two-layer structure formed on a copper plating layer according to the first embodiment, and FIG. 7B shows only one nickel plating layer according to the second embodiment. Is formed.

[0041]

According to the present invention, it is possible to provide antibacterial properties to nickel-chromium plating, which has been considered to be difficult in the past, and to carry out the present invention by making only slight changes to conventional plating equipment. it can. Accordingly, a high value-added faucet fitting having antibacterial properties can be provided at low cost.

[Brief description of the drawings]

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

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

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

Claims (6)

[Claims] 1. A nickel-chromium plating film having antibacterial properties, wherein 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 a range of µm. 3. The addition amount of the inorganic antibacterial agent particles is 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 thickness of the chromium plating layer is 0.1-1.
The antibacterial nickel-chromium plating film 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 nickel-chromium plating method having antibacterial properties, wherein nickel plating treatment is performed while stirring a nickel plating solution in which an inorganic antibacterial agent is dispersed, and then chromium plating treatment is performed.