Coatings

TPs or TS plastics may be used as a coating. The materials to be coated may be plastic, metal, wood, paper, fabric, leather, glass, concrete, ceramics, etc. Methods of coating are varied and include knife or spread coating, spraying, roller coating, dipping, brushing, and extrusion. Calendering of a film to a supporting material is also a form of coating.

Special methods can use powdered plastics for coatings. As an example the fluidized bed coating system. The object to be coated is heated and then immersed in a dense-phase fluidized bed of powdered plastic; the plastic adheres to the heated object and subsequent heating provides a smooth, pinhole-free coating. The electrostatic spray system is based on the fact that most plastic powders are insulators with relatively high volume resistivity values. Therefore, they accept a charge (positive or negative polarity) and are attracted to a grounded or oppositely charged object (which is the one being coated).

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