Substrates

For decorative plating on plastics, ABS (Acrylonitrile Butadiene Styrene) copolymer has been widely used. PC/ABS (Polycarbonate/Acrylonitrile Butadiene Styrene) polymer alloy is also used if high heat resistance is required.

DegreasingProduct name ACE CLEAN A-220(EDCM)

Remove oil, fat and dirt from plastic and clean the surface.
After degreasing, surface conditioning is often conduced to prevent air pocket occurrence in plating steps.
We have various air-pocket preventing agents (Product name: TOP PLACON series).

EtchingChromic acid-sulfuric acid based etchant

Dip plastic into highly concentrated chromic acid-sulfuric acid based etchant.
Selectively dissolve butadiene to minutely roughen plastic surface.

NeutralizationProduct name TOP CATCH CR-200, TMP NEUTRALIZER

Reduce chromium ions from hexavalent to trivalent, and remove the ions from plastic surface.

Pre-dippingHydrochloric acid

Dip plastic into hydrochloric acid bath.
After pre-dipping, proceed to the next process without water rinse.
Avoid water drag-in from pre-treatment into catalyzing steps.

CatalyzingProduct name CATALYST series

Make palladium-tin colloids adsorbed on plastic surface.
The colloids work as a catalyst in an electroless plating step.
We have a stabilizer for catalyzing baths (Product name: CATALYST STABILIZER).
The product can increase bath stability of catalyzing baths by replenishing tin (II) chloride.

AcceleratingProduct name ACCELERATOR series

Dissolve and remove excessive tin from palladium-tin colloids, and accelerating palladium.

Electroless nickel platingProduct name CHEMICAL NICKEL series

Conduct electroless nickel plating to make a primary conductive film before electroplating.
After this step, water rinse and copper electroplating is conducted.
In some cases, nickel strike electroplating is often conducted between electroless nickel plating and copper electroplating to ensure high conductivity.
We have a copper substitution agent (Product name: ANC ACTI) for the purpose.

Copper electroplating (Acid copper plating)Product name TOP DuNC CU series

To obtain metallic and shiny appearances, make etched plastic surface flat and smooth uniformly.
Plastic parts have weld lines where two flow fronts meet during molding process.
The additives for acid copper plating baths need to show high covering performance that can bury weld lines in order to avoid plating defects caused from molding process.

Semi-bright nickel platingProduct name TOP DuNC SB series

Deposit sulfur-free nickel plating films.
Semi-bright nickel films don’t contain sulfur; on the other hand, bright nickel films contain sulfur.
Thus, semi-bright nickel films indicate more noble electro-potential than that of bright nickel films.
By the difference in electro-potential, bright nickel plating films preferentially will corrode, and semi-bright nickel films will be protected from corrosion.
The additives for semi-bright nickel plating baths need to show high levelling performance and satisfy high-class mechanical properties.

(High corrosion resistant nickel plating)Product name TOP DuNC TN

If very strong corrosion resistance is required, tri-nickel plating is conducted.
The sulfur content in tri-nickel plating is the richest among three kinds of the nickel plating films, and the films indicates the least electro-potential among three kinds of the nickel plating films.
Thus, tri-nickel plating films preferentially will be damaged by sacrificial corrosion, and strongly protect semi-bright nickel films.

Bright nickel platingProduct name TOP DuNC BN series

For decorative and beautiful appearances, bright nickel plating is conducted.
The additives for bright nickel plating baths need to achieve bright and shiny appearances, and not to affect the covering performance of chromium plating.
For satin and matte finish, we have special additives (Product name: TOP DuNC ST series).

(Nickel plating for microporous chromium plating)Product name TOP DuNC POWDER FS, TOP DuNC MP series

For extremely high corrosion-resistance, use a nickel plating bath containing dispersed non-conductive fine particles.
When chromium plating is applied on this film, many micro-pores are formed in the films.
The micro-pores work to spread corrosion current over the surface, and we can achieve remarkably high corrosion resistance for a long term.
The additives need to realize uniform co-deposition regardless of the shapes and the areas of plated parts.

Chromium platingProduct name TOP DuNC CR series, TOP FINECHROME series, TOP FARBE series.

Chromium plating can give shiny, beautifully metallic appearances on plated parts.
Chromium plating requires excellent corrosion resistance and covering performance.
For silver-white color, we have TOP DuNC CR series (fluoride-based hexavalent chromium plating bath).
For grayish-white, gray and smoky colors, we have TOP FINECHROME series and TOP FARBE series (trivalent chromium plating bath).
We can provide you with many products from pre-treatment to various color variations to enable a wide range of color choices.

OKUNO's TECHNOLOGY: OKUNO’s strength for plating on plastic