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THERMOPLASTIC COATINGS

Thermoplastic powders can be coated using either the fluidised bed dip coating
process or by electrostatic spraying. The materials are supplied in powder (or liquid)
form and are usually applied in the factory by standard fluid-bed (fluidised bed) or
electrostatic spray techniques.Process methods vary. Both thermoplastics and
thermosets widely used in coating of numerous materials. Roller coating similar to
calendering process. Spread coating employs blade in front of roller to position
resin on material. Coatings also applied via brushing, spraying, and dipping.
Plastic Coating Types
• Plastic powder coating: is the process of applying a thermoplastic to the
surface of metal items to provide long-term corrosion, impact and chemical
resistance whilst offering an attractive decorative finish. Plastics tend to be
applied a little thicker than standard paints and are impermeable to water or
aggressive chemicals.
• Fluidised Bed Coating: A method of applying a coating of a thermoplastic
resin to an article in which the heated article is immersed in a dense-phase
fluidized bed of powdered resin and thereafter heated in an oven to provide a
smooth, pin-hole-free coating.
• Electrostatic spraying: Most commonly used powder application method in
which, an electrical charge is applied to the dry powder particles while the
component to be painted is electrically grounded. The charged powder and
grounded workpiece create an electrostatic field that pulls the paint particles
to the workpiece. The coating deposited on the workpiece retains its charge,
which holds the powder to the workpiece. The coated workpiece is placed in a
curing oven, where the paint particles are melted onto the surface and the
charge is dissipated.
• Flame Spraying: Method of applying a plastic coating in which finely
powdered fragments of plastic, together with suitable fluxes, are projected
through a cone of flame onto a surface.
• Extrusion Coating and Laminating: Mechanical process of building a laminate
by bonding repeated laminations, or layers, of material onto one another
• Dip Coating: Applying a coating to a part by simple dipping in a bath.
Example, tools coated with Plastisol or gloves production.
• Curtain Coating: Coating is employed with low viscosity resins or solutions,
suspensions, or emulsions of resins in which the substrate to be coated is
passed through and perpendicular to a freely falling liquid “curtain”
(or “waterfall”). The flow rate of the falling liquid and the linear speed of the
substrate passing through the curtain are co-ordinated in accordance with the
thickness of coating desired.
Applications:
Plastic coatings are widely used in pumps, vessels, valves, and pipelines for
process industries. They are used in food industries, gas, oil industries and also in
water treatment industries. used for protection of structural steel and concrete
structures and as tank linings in full time immersion. Offer excellent protection of
metal structures against corrosion, wear and tear and chemical attack

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