JP2000212759A - Plated product of urethane resin and its plating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a plating layer having excellent adhesion property and high quality and showing more similar appearance to metals by adding conductivity to the surface of an urethane resin base body and then electroplating the surface. SOLUTION: After the surface of an urethane resin base body 1 is softened with acetone or the like as pretreatment, the surface is chemically polished due to roughening in a potassium permanganate/sodium hydroxide mixture soln. at about 60 to 70 deg.C for about 5 to 15 min, and then the surface is neutralized. Then the surface is subjected to electroless copper plating at about 20 to 25 deg.C for about 5 to 20 min to form a chemical copper plating layer 2 of about 0.2 to 0.5 μm thickness to impart conductivity. Further, a copper electroplating layer 3 of about 30 to 50 μm thickness is formed to increase the thickness. Then a nickel electroplating layer 4 of about 5 to 30 μm thickness is formed as a base plating for the uppermost plating, and a chromium plating layer 5 of about 0.1 to 0.3 μm thickness is formed by flash treatment as the finish uppermost plating layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plated product of urethane resin and a plating method thereof.

[0002]

2. Description of the Related Art Conventionally, a process of plating a resin surface has been performed in order to improve the design and protection of a resin product. Various plating methods are selected depending on the properties of the resin.However, when plating urethane resin products, dry plating such as vacuum deposition is performed instead of wet plating due to the problem of adhesion. Was common.

[0003]

However, in the case of dry plating by vacuum evaporation or the like, there is a problem that the adhesion of the plating layer to the urethane resin is not sufficient, and peeling is likely to occur at the edge portion of the product. Further, since the thickness of the plating layer cannot be increased as compared with the wet plating, the design properties (color depth, etc.) have been poor. Furthermore, when the product has a free-form surface, there are problems that it is difficult to control the plating thickness, it is difficult to obtain a uniform plating layer thickness, and the equipment becomes large.

An object of the present invention is to provide a method of forming a high-quality plating layer having excellent adhesion to a urethane resin product and a plated product. .

[0005]

According to one aspect of the present invention, there is provided a plated product in which a metal plating film is formed on a surface of a urethane resin substrate, after the conductivity is imparted to the surface of the urethane resin substrate. Electroplating was performed. Thereby, electroplating is enabled by the imparted conductivity, and a plated product having a good plating layer can be obtained.

According to a second aspect of the present invention, electroless chemical plating is used as a means for imparting conductivity. Thereby, conductivity can be favorably imparted to the urethane resin surface, and a plated product obtained by electroplating the urethane resin surface can be obtained.

According to a third aspect of the present invention, chemical polishing is performed as a pretreatment for the electroless chemical plating. As a result, the surface of the urethane resin is roughened, and the treatment of the electroless chemical plating is ensured by the anchoring effect on the roughened surface when the electroless chemical plating is deposited. Electroplating can be performed, and a plated product having more excellent adhesion can be obtained. In addition, before the electroless chemical plating is performed, a catalyst is adhered to the urethane resin surface, and when the electroless plating is performed on the catalyst, the adhesion of the catalyst is improved by roughening by chemical polishing, which is more effective. .

In the present invention, a mixed solution of potassium permanganate / sodium hydroxide is used for chemical polishing. Thereby, the surface of the urethane resin can be roughened so as to be fine and porous, which is preferable. In addition, as long as the same effect can be obtained, the present invention is not limited to this mixed solution, and a gaseous phase may be used instead of the liquid phase.

According to a fifth aspect of the present invention, there is provided a plating method in which the surface of a urethane resin substrate is chemically polished, and then electroless plating is performed to impart conductivity, and thereafter, electroplating is performed. . This makes it possible to apply a plating with a higher surface design than the conventional plating using a vacuum deposited film to the urethane resin. Note that the above-described chemical polishing and catalyst application may be performed as a pretreatment for the electrolytic chemical plating.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to plate a urethane resin substrate surface (hereinafter abbreviated as "resin surface"), a softening treatment is first performed on the resin surface as a pretreatment for chemical polishing. As a chemical used for this softening treatment, acetone, trichlene, carbon tetrachloride or the like can be used. Next, chemical polishing is performed in a mixed solution of potassium permanganate / sodium hydroxide to roughen the resin surface. At this time, the solution composition was such that the concentration of potassium permanganate was 50 to 70 g / L, and sodium hydroxide:
0.9-1.2N, treatment conditions are 60-70 ° C and 5-1
Five minutes is preferred.

After the chemical polishing, the substrate is immediately immersed in a reducing agent such as an aqueous solution of sodium nitrite to neutralize the oxidizing agent: potassium permanganate remaining on the resin surface. Next, electroless chemical plating is deposited on the chemically polished resin surface to make the resin surface conductive. As the electroless chemical plating used in the present invention, electroless copper plating, electroless nickel plating, and the like can be applied. However, in order to improve the adhesion between the resin and the plating, the cushioning effect can be expected because the plating layer is relatively soft. Electroless copper plating is preferred. As a plating bath used for the electroless copper plating, a known plating bath such as a copper sulfate plating bath, a copper nitrate plating bath, and a Fehling bath can be used. When a copper sulfate plating bath is applied here, the composition of the plating bath is copper sulfate (pentahydrate): 10 to 15
g / L, Rossell salt: 30-50 g / L, formalin (37%): 20-30 g / L, sodium hydroxide: 1
About 0 g / L (pH: 12 to 13), to which thiourea as a stabilizer is added at about 1 mg / L. Many chemical copper plating solutions have been put on the market by plating chemical manufacturers, and the composition of the solutions is merely an example, and is not limited thereto. Further, the thickness of the chemical copper plating is set to 0.2 to 0.5 μm in consideration of performing the electrolytic copper plating in a later step, and the processing condition is about 20 to 25 ° C. for about 5 to 20 minutes.

The urethane resin product which has been made conductive by electroless copper plating is then further subjected to electrolytic copper plating in order to increase the copper plating thickness. The electrolytic copper plating thickness at this time is
The thickness is preferably set to a relatively large value of 30 to 50 μm in order to relieve the stress between the final plating layer and the urethane resin in the post-process.

Next, electric nickel plating is performed as a base plating for the uppermost layer plating. The plating thickness at that time is 5
The thickness is preferably 30 μm. Next, chrome plating, tin-cobalt plating, or the like can be applied as the finish uppermost plating. Of these two types of plating, tin-cobalt plating generates less stress on the plating layer than chromium plating and has a favorable effect on the adhesion between the resin and the plating layer. It is better to use both depending on the application of the product because of the depth and the excellent design. Regarding the plating thickness, both are 0.1 to 0.3
μm flash processing.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to make the present invention easier to understand, the present invention will be described in detail with reference to an embodiment applied when chrome plating is applied to a urethane vacuum cast product.

First, the surface area of the product is 3.0 dm ² (d means deci). As a urethane resin which is a material of the product, H & K Co., Ltd. high cast 3150 is used, and molding is performed by vacuum casting. The molded product is immersed in SU silicon off manufactured by Kansai Paint Co., Ltd. for degreasing and cleaning the surface, and then sufficiently dried. Thereafter, as a pre-treatment for chemical polishing, the molded article is immersed in trichlene to soften the resin surface, and then washed with water. In order to roughen the resin surface, a mixed solution of potassium permanganate / sodium hydroxide is used. Perform chemical polishing. At this time, the solution composition was a potassium permanganate concentration of 60 g / L, sodium hydroxide: 1.0 N, and the treatment conditions were 70 ° C. for 10 minutes.

Next, after washing with water, the product was immersed in an aqueous solution of sodium sulfite to neutralize the potassium permanganate remaining on the surface of the product. If confirmed, remove from the solution and immediately wash with water.

Next, a catalyst for electroless chemical copper plating deposition is applied in a mixed solution of palladium chloride / stannic chloride / hydrochloric acid. The solution composition at this time was palladium chloride: 0.2 g
/ L, stannous chloride: 10 g / L, hydrochloric acid: 150 ml / L
The treatment was performed at room temperature for 5 minutes. This treatment causes tin-palladium to adhere to the resin surface. Next, after washing with water, tin is removed from the tin-palladium adhering to the resin surface, and palladium is metallized. This metallization step is performed in sulfuric acid. The sulfuric acid concentration at this time is 100 g / L
The treatment was performed at 40 ° C. for 5 minutes.

Next, after washing with water, electroless chemical copper plating is deposited on the palladium catalyst adhering to the resin surface.
In the electroless chemical copper plating step, a copper sulfate plating bath was used.
The composition of the plating bath at that time was copper sulfate (pentahydrate): 10 g
/ L, Rossell salt: 50 g / L, formalin (37
%): 30 g / L, sodium hydroxide: about 10 g / L (pH: 12.5), and about 1 mg / L of thiourea as a stabilizer is added thereto. The processing conditions were 25 ° C. for 10 minutes.

Next, after washing with water, pickling with 98% sulfuric acid, and washing with water, electrolytic copper plating is performed. This treatment uses a copper sulfate plating bath, and the composition is copper sulfate (pentahydrate): 75 g / L,
Sulfuric acid: 180 g / L, brightener: appropriate amount, processing conditions: room temperature, current value: 3 A / dm ² , processing time: normal temperature, 60 minutes.

Next, after washing with water and rust preventive treatment, the electric
Perform nickel plating. The treatment at this time uses a watt bath,
Composition: nickel sulfate (hexahydrate): 250 g / L, dichloride
Hackel: 40 g / L, boric acid: 40 g / L, brightener and
Lubricant: proper amount, processing conditions at 50 ° C, current value: 3 A / d
m^TwoFor 15 minutes. And after washing with water, chrome
Perform plating. Use a Sargent bath for this
Chromic anhydride: 250 g / L, sulfuric acid: 1.5 g / L
The processing conditions are 45 ° C. and the current value is 15 A / dm. ^TwoAnd
The processing time was 3 minutes. Up to the top layer plating
The finished urethane resin product is used to improve the adhesion of the plating layer.
Dry thoroughly. Drying conditions are 75 ° C for 24 hours.
And

[0021]

According to the present invention, the following effects are exhibited by the above configuration. Compared to the conventional dry plating such as vacuum deposition, it is possible to obtain a product in which a plating layer having a high quality and a texture closer to a metal is provided on the urethane resin surface. Also,
The selectivity of the final plating layer is also expanded, and the use of the urethane resin product can be further expanded.

[Brief description of the drawings]

FIG. 1 Plating layer on urethane resin

[Explanation of symbols]

1 ... urethane vacuum cast product (after chemical polishing), 2 ... chemical copper plating layer, 3 ... electric copper plating layer, 4 ... nickel plating layer,
5 ... Chrome plating layer

Claims (5)

[Claims] 1. A urethane resin-plated product in which a metal plating film is formed on a surface of a base material, wherein electroplating is performed after imparting conductivity to the surface of the base material. 2. The urethane resin-plated product according to claim 1, wherein electroless chemical plating is used as the conductivity imparting means for imparting the conductivity. 3. The urethane resin-plated product according to claim 2, wherein chemical polishing is performed as a pretreatment of said electroless chemical plating. 4. The urethane resin plated product according to claim 3, wherein a mixed solution of potassium permanganate / sodium hydroxide is used as said chemical polishing. 5. A plating method for forming a metal plating film on a surface of a urethane resin substrate, wherein the surface of the substrate is chemically polished, and then electroconductivity is applied to the surface by electroless chemical plating. A plating method of urethane resin, wherein plating is performed.