Painting Plastics

Question:

Could you provide me with more information on non-metallic coatings on plastics, like plastic coatings on a plastic substrate? What is the process? Thank you for any help and/or advice that you can give. A. V.

Answer:

To cover the subject of coating plastic substrates would require an entire chapter. Simply stated, the same rules that apply to coating other substrates also apply to plastic substrates. The substrate must be clean, free from oily soils and particulates. In some cases, the substrate must be pretreated. The coating to be applied must be compatible with the substrate. The substrate must have structural integrity.

Plastic substrates are cleaned using alkaline cleaners, detergent cleaners, emulsion cleaners and solvents. If necessary, plastic substrates are pretreated using abrasives, chemical etching, corona discharge, flame treating, plasma treating and lasers. In some cases 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 dissolve or otherwise destroy the substrate. Although, it is possible that the solvent attack can promote adhesion. The structural integrity of a substrate is important, because you can’t rely on the coating to hold it together.