JPS58104169A - Electroless plating method - Google Patents

Abstract

PURPOSE:To form metallic plating having fine appearance with a small amount of a plating soln. by coating a metal or plastics with the plating soln. contg. a water soluble binder, a metallic salt or a metallic complex salt, and a reducing agent and by carrying out heating. CONSTITUTION:A plating soln. contg. a water soluble binder, a metallic salt or a metallic complex salt, and a reducing agent is prepared. Starch, water soluble cellulose, tannin or the like is used as the water soluble binder. The metallic salt or the metallic complex salt is required to deposit metallic ions of Ni, Au, Ag, Co, Sn or the like by the action of the reducing agent. Formalin, tartaric acid, reducing sugar or the like is used as the reducing agent. The metallic ion concn. of the plating soln. is adjusted to 0.01-10mol/l. A metal or plastics is coated with the plating soln. and heated at 50-150 deg.C for 2-30min.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel electroless plating method applied to metals or plastics.

Electroless plating is a plating method that uses a chemical reaction, and unlike electroplating, it does not require the flow of current, so it has recently become more practical because it can directly plate plastic, which is a poor current conductor. Ta. However, the electroless plating that has been practiced so far requires a large amount of plating bath and has poor storage stability. First, there is a problem in that the plating bath must be treated as waste water after use, which requires a lot of cost.

The present invention was made in view of the above-mentioned problem, and it is an object of the present invention to perform metal plating with a stable and beautiful appearance using a small amount of plating solution.

In order to achieve the above object, the present invention uses a plating solution in which an aqueous binder is added to a solution containing a metal salt or a metal complex salt and a reducing agent, and the plating solution is coated on metal or plastic. An object of the present invention is to provide an electroless plating method comprising applying and heating.

Here, the "electroless plating method" as used in the present invention is different from the conventional method of plating by dipping the material to be plated in a plating bath. A method of applying metal plating.

As mentioned above, the present invention is characterized by the use of a water-soluble binder, and the effects of adding this binder include increasing the hot water temperature of the plating bath, delaying the reduction reaction of the plating bath at room temperature, and reducing the damage to the material to be plated. Possible reasons include an increase in coating efficiency.

Furthermore, as the metal precipitation reaction in the plating solution becomes uniform, plating with a beautiful appearance can be obtained, and the reduction reaction of the plating solution at room temperature is slowed down, so that the plating solution becomes stable.

Next, the main components constituting the plating solution in the present invention will be explained. Water soluble,? Inders include starch, water-soluble cellulose, tannin, alginic acid, sodium alginate, and gum arabic.

Polyvinyl alcohol, polyethylene oxide, polysodium acrylate, polyacrylic acid, polyvinylpyrrolid 7, #l hydromaleic acid, acrylic acid, phthalic acid,
Gelatin, etc. or combinations thereof can be used. Metal salts nickel, gold, silver, cobalt, tin, lead,
It precipitates metal ions such as zinc, and can be any of those used in conventional electroless plating baths, such as silver nitrate, potassium silver cyanide, hypophosphorous Je@nickel, cyanide, etc. Potassium gold chloride, silver ammine complex, silver cyanide anchor, gold salt or gold cyanide complex, etc. can be used. Examples of reducing agents include formalin,
Tartaric acid, tartrate, reducing sugar, anhydrous phosphite, hypophosphite, sodium borohydride, dimethylamine borane, hydrocarbon, and the like can be used. In addition to the above-mentioned components, buffers such as formates, acetates, and other additives can be used.

Note that when a metal is used as the material to be plated, a reducing agent is not necessarily required, and it is appropriate to adjust the metal ion concentration in the plating solution in the present invention to a range of α01 to 10 mol/l. It is.

As can be understood from the above, according to the present invention, the metal salt is converted into a metal complex salt. Thanks =
2, gold, silver, 3 ba 2. .

Metals or plastics can be plated with desired metals such as tin, carbon, zinc, etc.

Next ridge The electroless 7 plying method of the present invention will be generally described. First, the material to be plated is pretreated in the same manner as in the conventional electroless plating method. In the case of metals, the pretreatment may be as simple as washing with water and degreasing, but in the case of plastics, washing with 1M8 water, -touching, sensitization treatment, activation treatment, etc. are required. Next, the pretreated material to be plated is coated with a plating solution using a commonly used coating method. As an application method, brush application, roller application, one-turn wheel application, spray application, etc. can be used. The thickness of the coating film (appropriately ranges from 11μ to 300μ).
Heat the coating. Heating Fiso~2~ at a temperature of 150℃
A period of 30 minutes is appropriate.

The present invention will be explained below with reference to Examples, but the present invention is not limited thereto.

Example 1 Polyvinyl alcohol (7 excellent aqueous solution) 50g
Formamide 5-silver nitrate
15.9 Ammonia water 30-50 dextrose solution 20-A solution consisting of the above components was spin-coated onto a pretreated acrylic plate to a thickness of 3 μm.
A silver plating film with a beautiful appearance was obtained by coating the silver plating film to a thickness of 20% and heating it at 80° C. for 5 minutes. □ Example 2 Polyvinyl alcohol (7T aqueous solution), -10(
Nickel hypophosphite 279 Enemy 51i Ammonium sulfate 511 Sodium acetate
5g water
20wj After applying the liquid with the above ingredients to a thickness of 3μ by spin coating on a pretreated acrylic plate, heating it at 80℃ for 5 minutes and washing with water, the appearance is -J.
A thick nickel plating film was obtained.

Example 6 A steel plating film with a beautiful appearance was obtained in the same manner as in Fi Example 1 except that a liquid consisting of the following components was used.

Polyvinyl alcohol (7-water @ enemy) 100
111′1::,,・i Copper chloride 10g EDT Mu-4Na field 50
．． 9 Formalin 1011 Sodium hydroxide 109 Example 4 Polyvinyl alcohol (7 excellent aqueous solution) 20 (
['Nickel sulfate 25g Sodium hypophosphite 25I Sodium pyrophosphate 50I After applying a solution consisting of the above ingredients to a pretreated iron plate, it was heated at 120°C for 5 minutes to obtain a nickel film with a beautiful appearance.

Furthermore, on top of the metal plating applied by the method of the present invention, it is also possible to separately apply plating by conventional electroplating.

As described above, according to the electroless plating method of the present invention, it is only necessary to apply enough plating solution to the material to be plated to form a coating film, so the amount of plating solution used can be very small. Therefore, there is less waste water and plating can be performed at low cost.

Claims (1)

[Claims] Water-soluble binder for metal or plastic. The metal salt is coated with a plating solution containing a metal complex salt and a reducing agent and then heated. Electroless plating method.