Although plastics can replace metal in many occasions, but it is clear that it lack of metallic texture. For this, it need to adopt a certain way, in the plastic surface coated with a layer of metal (aluminum, Zinc oxide, copper, silver, gold, chromium, etc.), a method is similar plating and electroplating methods, the other is directly on the plastic surface of the vacuum deposition of metal - that is, in a vacuum, the metal melted to form molecules or atoms deposited on the plastic surface of the formation of 5-10μm metal film.
Vacuum deposition of metal and plastic surfaces need a good match between the primer, primer thickness is usually 10-20μm, the main role is to prevent the plastic water, organic solvents, plasticizers and other discharges affect metal adhesion. Required coating hardness, can be modified with a plastic primer defects, can provide a smooth, flat surface in order to facilitate the performance of vacuum coating and the substrate and the gold-plated and plastic are attached to a solid. Usually use two-component room temperature curing polyurethane and epoxy coatings, low-temperature baking of the amino thermoplastic acrylic coatings and paints.
Metal oxide coating is easy to darken in the air, but also subtle defects such as vacuum, so again coated with a layer of 5-10μm protection finish. On the finish requirements are: transparent, excellent water resistance, abrasion resistance, weather resistance, does not operate plated film, Titanium dioxide firmly attached to the metal coating. Usually be acrylic varnish, polyester varnish, polyurethane varnish, etc., when the primer is used in thermoplastic acrylic paint, paint solvents in order to prevent corrosion by coating defects in primer, you can use a weak solvent, quick-drying the finish, such as acrylic modified alkyd varnish, polyvinyl butyral varnish, urethane oil.
Vacuum metallization process: the plastic surface treatment (cleaning, activation) → → drying → priming vacuum metallization → → drying topcoat. A brief description of its process: surface cleaning products -> to static -> spray paint -> baking primer -> vacuum coating -> spray paint -> Baking finish -> packing.
In all of the process, the following points determines the success or failure of technology: the need for processing of the surface state components, including product defects, surface, surface contamination, etc.; the presence of surface defects may lead to the final aesthetic appearance of parts degree. Of course, for the presence of small defects, spraying can cover up. But in the process of injection molding or stamping molding defects caused by the bulk purchase of test materials must be excised before. Surface state, which involves whether it is a transparent material, Nickel oxide the surface roughness of a special design. Appearance of the state design requirements, must be considered before the enactment of the overall process process route, otherwise difficult to obtain the desired finished appearance. Surface contaminants, for bulk products, how to remove residual contaminants preceding process is the key to relationship quality and efficiency. For example, in injection molding release agent generated in the process of removal. Source: