Paint on Plastics
Question: I need information on the pretreatment and coating of plastic parts.
I need information on the pretreatment and coating of plastic parts. I have been out of the automotive coating industry for three years (after eight years of electrocoat experience) and am trying to re-enter it. I need to brush up on plastic coating technology information. I would appreciate any help. S. T.
Not much has changed in pretreating and painting plastics in the past three years. The rules for painting plastic substrates are still the same as painting other substrates. The substrate must be clean, free from oily soils, release agents and particulates. Certain plastic substrates must be pretreated to promote adhesion. The applied coating must be compatible with the substrate.
To remove oily soils, plastics are cleaned using alkaline cleaners, detergent cleaners, emulsion cleaners and solvents. Release agents are best removed using recommendations from their suppliers. If necessary, plastic substrates are pretreated using abrasives, chemical etching, corona discharge, combustion spray, plasma spray and lasers. Some plastic substrates must be primed to promote adhesion or to prevent attack by the solvents in a topcoat.
Compatibility of the coating with the substrate means its solvents should not attack, dissolve or otherwise destroy the substrate, although, it is possible that the solvent attack can promote adhesion.
Masking is employed in most any metal finishing operation where only a specifically defined area of the surface of a part must be exposed to a process. Conversely, masking may be employed on a surface where treatment is either not required or must be avoided. This article covers the many aspects of masking for metal finishing, including applications, methods and the various types of masking employed.
Some that bears precious metals is, and there are a host of regulations to consider when recycling.
Simply heating up the substrate does not cure the coating. There are many variables to consider when choosing the best cure oven for your application...