Coating processes electrostatic spraying

Method of processing electrostatic spray coating, fluidized bed coating, rotational molding, slush molding ... 

Unreinforced PPS resins are also available for use in slurry coating and electrostatic spraying. Resin coatings are suitable for food-contact applications as well as chemical processing equipment. 

The volume of thermosetting powders sold exceeds that of thermoplastics by a wide margin. Thermoplastic resins are almost synonymous with fluidized-bed appHed thick-film functional coatings whereas thermosetting powders are used almost exclusively in electrostatic spray processes and appHed as thin-film decorative coatings. 

Almost all PVC powder coatings are appHed by the fluidized-bed coating process. Although some electrostatic spray-grade formulations are available, they are very erratic in their appHcation characteristics. The resistivity of plasticized PVC powders is low compared to other powder coating materials and the appHed powder quickly loses its electrostatic charge. For the same reason, PVC powders show poor appHcation characteristics in an electrostatic fluidized bed and are seldom used in this process. 

Powder coating is a solventless coating system that is not dependent upon a sacrificial medium such as a solvent, but is based on the performance constituents of solid TP or TS plastics. It can be a homogeneous blend of the plastic with fillers and additives in the form of a dry, fine-particle-size compound similar to flour. The three basic methods are the fluidized bed, electrostatic spray, and electrostatic fluidized bed processes (9). 

Electrostatic spray Charged particles are sprayed on electronically conductive parts process gives high paint utilization more expensive than conventional spray. Spray gun, high-voltage power supply pumps dryers Pretreating station for parts (coated or preheated to make conductive). 

The electrostatic spraying is a technique designed for the automatic or semiautomatic coating of articles on a conveyer system. The atomized paint is attracted to the conductive object to be painted by an electrostatic potential between the two. This process now finds widespread use in the automobile industry. Several car producers have installed fully automated electrostatic multiple gun systems capable of applying high solid and water-based coatings. 

Half of the normally oversprayed material is thus captured as useful coating. To the average spray finishing operation a reduction of 25% in the amount of material required to do the job is already a sizable saving. Because of this possible saving, this electrostatic spray process has been used by industry to coat many types of items from automobiles to bicycles. 

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