Plastic electroplating (POP) process
Plastic electroplating (POP) requires some special techniques because the substrate is non-conductive.Among them, the metal nickel plays a very important role in it.
As early as the early 1960s, plastic electroplating was introduced into the European and North American markets on a limited commercial basis.The main breakthrough that has led to good growth in the industry is the development of the surface treatment chemical process of acrylonitrile-butadiene-styrene (ABS), which makes a good combination between the plastic substrate and the metal coating.ABS makes plastics widely used in electroplating and the electroplated workpieces also have good quality.
Generally speaking, the process used for plastic electroplating includes the following stages：
▪ Plastic surface corrosion provides a hydrophilic surface and good binding force. Generally, the etchant consists of a concentrated chromic acid solution and sulfuric acid. However, the effectiveness of etching depends to a large extent on the surface condition and the composition of the substrate.
▪ Etching the surface causes catalytic points to be generated on the non-conductive plastic, so that chemical nickel or chemical copper can be deposited on the surface.
These points are usually produced by potions containing palladium chloride and tin salt, which makes the palladium particles very evenly distributed on the plastic surface.
▪ Deposit a thin layer of electroless nickel-plated or chemical copper-plated film to make it a conductive substrate for traditional electroplating.
Once this conductive deposition is generated, the workpiece can be used for conventional electroplating.
The main driving force of POP is the automotive industry.The growth of fuel economy demand requires reducing the weight of vehicles. This industry has discovered that plastics are durable, lightweight, and easier to manufacture.All plastic substrates have the potential to replace traditional metal materials such as zinc die castings at a lower cost.Therefore, plastic materials are widely used in the auto parts industry such as grilles, light frames, car signs and bright decorations.
The rapid development of technology has begun to spread to other markets (but the use of automobiles still dominates).Plastic electroplating is widely used, such as bathroom and kitchen accessories, control handles for electronic equipment, button electroplating on clothes, and various household and personal care products.Therefore, from the slow start in the 1960s to the rapid growth in the early and mid-1970s, many electroplators began to provide POP services.
Automobile ABS electroplating (sardine nickel) process
Feeding → degreasing → washing → pre-etching → hot water washing → washing → whole surface → etching → recycling → washing → no washing at all
→ Neutralization → washing → prepreg → activation → washing → degumming (acceleration) → Washing → chemical nickel → spray washing → Washing
→ Acid leaching → washing → Impact nickel → recovery → washing → chemical copper → washing → acid copper → recovery → washing
→ Acid immersion → washing → semi-light nickel → bright nickel → washing → pickling → washing → sardine nickel → washing → microporous nickel
→ Washing → pre-chromium activation → washing → trivalent chromium → recovery → washing → passivation → washing → hot water washing → wind blowing
→ Drying → cutting → chrome stripping → washing → copper-nickel stripping → washing → nitric acid stripping → washing → hot water washing → Blow drying