JP2020200518A - Chemical plating method - Google Patents

Abstract

To provide a chemical plating method capable of manufacturing a good quality plating product without using a surfactant used in a traditional cleaning fluid and optionally reducing a usage amount of a reducer used for forming a metal plating film.SOLUTION: After cleaning treatment of non-metal substrate surface using a cleaning liquid containing a nanobubble of one or two or more of nitrogen, air, and hydrogen, a metal plating treatment is performed on this substrate surface. A plating liquid used for a metal plating treatment preferably contains the nanobubble of either of or both of air and hydrogen.SELECTED DRAWING: None

Description

The present invention relates to a chemical plating method (electroless plating method) in which a metal plating treatment is performed on the surface of resin, glass or the like.

In the chemical plating method, an expensive metal particle such as palladium is used as a core, a plated metal film is grown using a reducing agent, and a metal plating film is formed on the surface of a base material (insulator) such as resin or glass, which is the object to be plated. It is a method of forming (a method that does not use current).
In this chemical plating method, a cleaning liquid containing a surfactant is used for the pretreatment to remove oils and fats and dust adhering to the surface of the base material, so that waste liquid is generated and the components of the surfactant are also generated. There is a problem that uneven plating occurs due to the residue remaining on the surface.

As the chemical plating method, for example, the techniques of Patent Documents 1 and 2 are disclosed.
In Patent Document 1, a surface modification treatment is performed in which the surface of a resin base material is brought into contact with ozone water containing fine ozone bubbles having an average particle size of 0.1 μm to 100 μm to modify the surface of the base material. Above, a method of forming a metal layer on the surface of this base material by electroless plating is disclosed.
Patent Document 2 describes a method of using an electroless plating solution containing fine bubbles containing fine bubbles having an average cell diameter of 10 nm or more and 50 μm or less when the nanofibers are electroless plated to produce conductive nanofibers. Is disclosed.

Japanese Unexamined Patent Publication No. 2013-189667 Japanese Unexamined Patent Publication No. 2016-138314

However, the technique disclosed in Patent Document 1 is a method in which ozone water is brought into contact with the surface of the base material to perform surface modification treatment (improvement of adhesion of the metal layer), and is also disclosed in Patent Document 2. The technique is a method of electroless plating the produced nanofibers as they are without pretreatment, and none of the techniques disclosed in Patent Documents 1 and 2 describe a method of cleaning the surface of a base material. In Patent Document 2, it is described that nanobubble water is used for cleaning the substrate before plating in the column of the problem to be solved by the invention, but it is merely described as nanobubble water. The specific configuration is not described.

In the chemical plating method, as described above, a large amount of reducing agent is used for forming the metal plating film, and since this reducing agent is hypophosphorous acid, formaldehyde, which is a deleterious substance, or the like. For example, special treatment may be required to dispose of the waste liquid of the plating solution (plating bath), and the phosphorus component of hypophosphorous acid remains in the plating film, making the plating surface dull and having good reflective luster. Practical defects such as disappearance and mold growth may occur.
However, all of the techniques of Patent Documents 1 and 2 positively use a reducing agent, and the above-mentioned problems may occur.

The present invention has been made in view of such circumstances, and the amount of the reducing agent used for forming the metal plating film may be reduced without using the surfactant conventionally used for the cleaning liquid. It is an object of the present invention to provide a chemical plating method capable of producing a plated product of good quality with a reduction as compared with the conventional method.

In the chemical plating method according to the present invention according to the above object, the surface of a non-metal base material is cleaned with a cleaning solution containing one or more nanobubbles of nitrogen, air, and hydrogen, and then the surface is cleaned. The surface of the base material is metal-plated.

In the chemical plating method according to the present invention, it is preferable that the plating solution used for the metal plating treatment contains nanobubbles of either one or both of air and hydrogen.

In the chemical plating method according to the present invention, the base material is preferably made of resin or glass.

In the chemical plating method according to the present invention, the surface of the base material is cleaned with a cleaning solution containing nanobubbles of any one or more of nitrogen, air, and hydrogen, and thus the interface conventionally used in the cleaning solution. No activator (cleaning agent) is required.
Therefore, since it is not necessary to treat the waste liquid after the cleaning treatment, it is possible to economically manufacture the plated product with good workability and to eliminate the occurrence of uneven plating due to the residual surfactant component remaining on the surface of the base material. Therefore, it is possible to manufacture plated products of good quality.

Furthermore, when the plating solution used for the metal plating treatment contains nanobubbles of either one or both of air and hydrogen, the amount of the reducing agent used for the metal plating treatment can be significantly reduced as compared with the conventional case. , The special treatment associated with the disposal of the waste liquid of the plating solution can be reduced and eliminated, and the dullness and mold generation of the plating surface due to the phosphorus component of the reducing agent can be suppressed to the extent that there is no problem with the product quality. , And even more can be eliminated.

Subsequently, an embodiment embodying the present invention will be described for understanding the present invention.
The chemical plating method according to an embodiment of the present invention comprises nanobubbles of any one or more of nitrogen (N ₂ ), air, and hydrogen (H ₂ ) on the surface of a non-metallic substrate. This is a method of performing a metal plating treatment on the surface of this base material after a cleaning treatment using a cleaning liquid. The details will be described below.

The base material is made of non-metal, for example, resin or glass (ceramics).
Here, when the base material is made of resin, the base material is, for example, a molded product formed by injection molding using a mold or the like, and is substantially a product in which a metal plating layer is formed on the molded product. It has the same shape (the shape is the same for the glass base material).
The products on which the metal plating layer is formed include, for example, home appliances (parts), automobile parts, and the like, but are not limited thereto.

Here, examples of the resin (raw material of the base material) include ABS resin (acrylonitrile / butadiene / styrene), PC / ABS resin (polycarbonate / acrylonitrile / butadiene / styrene), PC / PET resin (polycarbonate / polyethylene terephthalate), and the like. PC / PBT resin (polycarbonate / polybutylene terephthalate), LCP resin (liquid crystal polymer), PA resin (polypropylene), PA / ABS (polycarbonate / acrylonitrile / butadiene / styrene), PPE resin (polyphenylene ether), PP resin (polypropylene) , PPS resin (polyphenylene sulfide), SPS resin (crystalline polystyrene), PS resin (polystyrene), MMA resin (methyl methacrylate), epoxy resin, urethane resin, PET resin (polycarbonate terephthalate), PBT resin (polybutylene terephthalate) , PC resin (polycarbonate) and the like, and further, a polymer alloy of these resins may be used.

(Washing process)
The above-mentioned substrate is cleaned.
For the cleaning treatment, a cleaning liquid containing nanobubbles of any one (single) or two or more (combination) of nitrogen, air, and hydrogen is used.
This nanobubble is an ultrafine bubble that can be produced by a conventionally known device, and means a bubble that is smaller than the microbubble and has a diameter of several hundred nm or less. In order to enhance the effect of the cleaning treatment, the diameter of the nanobubbles is preferably about 100 nm or less (preferably less than 100 nm, more preferably 50 nm or less). On the other hand, the lower limit value is not particularly limited, but is, for example, about 10 nm.

As a method of cleaning the base material with a cleaning liquid containing nanobubbles, for example, a method of putting (immersing) the base material in a container containing a cleaning liquid containing nanobubbles (batch processing), or a method of putting the base material in a container in which the base material is put. A method of continuously supplying nanobubbles to a solvent (water, volatile solvent (ethanol), etc.), a method of continuously supplying a cleaning liquid containing nanobubbles into a container in which a base material is placed (continuous treatment or circulation treatment). ) Etc.
As a method for producing a cleaning liquid containing nanobubbles, for example, there are a method of generating nanobubbles with a solvent stored in a container into which a base material is put, a method of supplying a solvent containing nanobubbles to a solvent stored in the container, and the like. The solvent may contain components other than the above-mentioned surfactant (for example, other cleaning agents).

Here, the amount of nanobubbles contained in the cleaning liquid may be such that the effect of the cleaning treatment can be obtained. For example, hundreds of millions of nanobubbles (1 to 4 billion, and even 1 to 1) are contained in 1 mL (milliliter) of the solvent. About 500 million pieces) should be included.
The time required for the cleaning treatment of the base material can be appropriately changed depending on the material and surface condition of the base material, but may be, for example, about 10 minutes or less (preferably 5 minutes or less, more preferably 3 minutes or less).
As a result, the base material can be cleaned.

(Catalyst addition treatment)
Next, a conventionally known catalyst-imparting treatment is performed on the base material that has been cleaned.
This catalyst application treatment is a treatment for adhering seeds of plating growth for performing a metal plating treatment described later, and various catalysts to be used can be selected depending on the type of reducing agent used in the metal plating treatment. For example, when hypophosphate is used as the reducing agent, palladium (Pd) can be used as the catalyst, and for example, iron group elements such as iron (Fe), nickel (Ni), cobalt (Co) and platinum. Group elements can also be used. The reducing agent is not limited to hypophosphorous acid, and for example, a conventionally known reducing agent such as formaldehyde can be used. In this case, the catalyst used varies depending on the type of reducing agent. You can choose.

(Metal plating)
Subsequently, the base material for which the catalyst application treatment has been completed is washed with water, and then the base material is subjected to a metal plating treatment.
This metal plating treatment is a treatment for forming a metal plating film on the surface of a base material, and examples of the types of metal plating film to be formed include nickel, cobalt, copper (Cu), and tin (Sn). There are alloys of any one or more of the above, gold (Au), platinum (Pt), silver (Ag) and the like.

The plating solution used for the metal plating treatment contains nanobubbles of either one or both of air and hydrogen (air and / or hydrogen). The nanobubbles have the same size as the nanobubbles contained in the cleaning liquid described above, and the nanobubbles are further included in the composition of the plating solution conventionally used for the metal plating treatment.
The amount of nanobubbles contained in the plating solution may be any amount as long as the amount of the reducing agent contained in the plating solution can be reduced as compared with the conventional one. Similar to the cleaning solution described above, for example, hundreds of millions of nanobubbles are contained in 1 mL of the solvent. It suffices to contain about (1 to 4 billion pieces, and further to 100 to 500 million pieces).

As a result, the amount of the reducing agent contained in the plating solution can be reduced to, for example, 50% by mass or less, preferably 20% by mass or less, and more preferably 10% by mass or less of the amount normally used (preset amount). .. On the other hand, the lower limit of the amount of the reducing agent may be, for example, about 5% by mass of the amount normally used.
After forming the metal plating film on the surface of the base material by the above method, a product is obtained by performing a washing treatment and a drying treatment (heat treatment). The above-mentioned metal plating treatment, washing treatment, and drying treatment may be repeated a plurality of times until the required plating thickness is obtained.

Next, an example carried out for confirming the action and effect of the present invention will be described.
Here, a plastic piece (an example of a non-metal base material) was used as the object to be chemically plated, and the effect of the present invention was examined.
First, a cleaning solution was produced.
Specifically, three types of cleaning liquids (nanonitrogen water, nanoair water, and nanohydrogen water) containing nanobubbles of nitrogen, air, and hydrogen were produced.
Then, the above-mentioned plastic pieces were immersed in each cleaning solution for 1 minute.

Subsequently, the cleaned plastic pieces were subjected to a conventional palladium-imparting treatment (catalyst-imparting treatment) and then nickel-plating treatment (metal plating treatment).
For this nickel plating treatment, a conventional nickel plating bath containing no nanobubbles and two types of nickel plating solutions containing nanobubbles of air or hydrogen were used, respectively. The amount of the reducing agent used in each nickel plating solution containing nanobubbles was reduced to 10% by mass of the amount normally used.

Here, when a normal nickel plating bath was used for the nickel plating treatment, a good nickel plating film was formed on each of the plastic pieces cleaned with the above-mentioned three types of cleaning liquids. As a result, it was confirmed that oils and fats and dust were efficiently removed from the surface of the base material.
On the other hand, when the nickel plating solution containing various nanobubbles was used and the nickel plating treatment was performed at 80 ° C., it was confirmed that the nickel plating solution containing air nanobubbles produced a nickel plating film having extremely good and metallic luster. .. This is because the residual phosphorus in the nickel plating film was extremely small and good gloss could be achieved.
For the nickel plating solution containing hydrogen nanobubbles, the nickel plating film was not formed well. However, this is because the above-mentioned palladium particles have been removed from the surface of the plastic piece due to the strong cleaning effect of the hydrogen nanobubbles, and the amount of hydrogen nanobubbles contained in the nickel plating solution should be adjusted. So, the above problem has been solved.
For reference, it was found that the use of nitrogen is not appropriate in the nickel plating solution containing nanobubbles of nitrogen because metal particles such as nickel are generated in the solution.

From the above, by using the chemical plating method of the present invention, the amount of the reducing agent used for forming the metal plating film can be reduced without using the surfactant conventionally used for the cleaning liquid. It was confirmed that it was possible to manufacture plated products of good quality with less reduction than before.

Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the configuration described in the above-described embodiments, and the matters described in the claims. It also includes other embodiments and variations that may be considered within the scope. For example, the case where the chemical plating method of the present invention is constructed by combining some or all of the above-described embodiments and modifications is also included in the scope of rights of the present invention.
In the above embodiment, the case where the base material is sequentially subjected to the cleaning treatment and the catalyst application treatment and then the metal plating treatment is performed has been described, but the base plating treatment is performed before the metal plating treatment is performed ( It is also possible to form a base plating layer).

Further, in the above-described embodiment, the case where both the cleaning solution used in the cleaning treatment of the base material and the plating solution used in the metal plating treatment of the base material contain nanobubbles has been described, but the cleaning liquid contains nanobubbles. The plating solution does not have to contain nanobubbles. When nanobubbles are contained in both the cleaning solution and the plating solution, the types of nanobubbles may be the same or different, but it is preferable to select different types according to the cleaning treatment and the application of the plating solution.

By using the chemical plating method according to the present invention, the amount of the reducing agent used for forming the metal plating film can be reduced without using the surfactant conventionally used for the cleaning liquid. It is possible to produce a plated product of good quality with less reduction. Thereby, for example, the chemical plating method of the present invention can be applied to an industrial chemical plating apparatus, and can also contribute to the expansion of applications of the nanobubble generator.

Claims (3)

After cleaning the surface of a non-metal base material with a cleaning liquid containing one or more nanobubbles of nitrogen, air, and hydrogen, the surface of the base material is metal-plated. Characterized chemical plating method. The chemical plating method according to claim 1, wherein the plating solution used for the metal plating treatment contains nanobubbles of either one or both of air and hydrogen. The chemical plating method according to claim 1 or 2, wherein the base material is made of resin or glass.