Electrostatic powder painting

A 13.9 Electrostatic technique of powder painting 13/409 A13.I0 Effluent treatment and fume control 13/4l2... 

Special filling goods and a long shelf life sometimes require an extremely high dry film thickness for the welding seam coating. Powder paints are then applied electrostatically to give a dry film thickness of ca. 50 pm. 

Raybo Powder Additive 210 conductivity modifier, electrostatic spray paints Talllcin 4900 consistency agent... 

Spraying Here the powder paint is electrostatically charged and sprayed on to the part which is at earth, or ground potential. The spray gun imparts a charge on the powder which is attracted to and wraps around... 

Section 3.7 lists dusts which could be an explosion hazard. It refers to dust clouds ignitable by a spark. Probably the item spray paint should be spray powder paint , as applied by electrostatic spraying, which is prone to ignition from a static spark. 

Powder paints are commonly applied by electrostatic spraying on metal substrates. The powder particles are charged inside the spray gun (Corona or Tribo) and adhere to the earthed metal object. Powder coating is ideal for coating complicated three-dimensional objects because the powder particles can easily reach recessed surfaces or even the backside of surfaces, following the electrical field lines from the gun to the substrate. Powder paint which does not reach the object or disassociates from the surface ( overspray ) can easily be gathered, recycled, and re-used without loss of quality (Figure 16.6). The substrate, covered with a layer of powder paint, is subsequently heated in a hot-air oven. The powder particles melt, coalesce, and fiow out into a film. 

Filiform corrosion occurs with all types of paints acrylic lacquers, epoxy-polyamides, epoxy-amines and polyurethanes, and whatever the classic mode of application, whether with liquid paint or electrostatic powdering. It does not occur under sealed coatings such as electrician s tape. 

Electrostatic method This is also a w et method like the conventional process, except that the paint is now electrostatically charged, similar to the powder ptiint in a dry method as discussed later. The paint, being highly charged electrostatically, is wrapped around the object automatically. 

Industrial painters may suffer adverse health effects from over exposure to paint by skin contact or accidental ingestion, from excessive inhalation of paint aerosol, solvent vapour, or of dust in the case of electrostatically-applied powder coatings (e.g. polyesters containing triglycidyl isocyanurate), or from exposure to thermal degradation products from heated paint or plastic coatings (Table 5.48). 

The supply chain for this process can be seen in Fig. 8.11. Electrostatic spray coating or powder coating is a way of applying a dry paint to a surface. Most people have used liquid paints with a brush, a spray can, or even with their fingers. Powder coatings are dry there are no liquid solvents. The dry powder is applied to an item (substrate), then the powder is turned to liquid, usually by melting. The dry powder in its molten state can then flow out to cover the substrate, coalesce, and crosslink. The end result is a painted surface. 

The electrostatic spraying of polymer powders utilizes the principle that oppositely charged particles attract, a principle that has been used for many years in spraying solvent-based paints. In electrostatic spraying, polymer powder is first fluidized in a bed to separate and suspend the particles. It is then transferred through a hose by air to a specially designed spray gun. As the powder passes through the gun. 

Inmold powder lacquering or inmold painting can be used to produce surface coating on some compression molded parts. Powder lacquer, preferably UP resin, is injected electrostatically into the hot mold, which is opened by 100-200 pm and forms an integral layer with the molded part when the mold is reclosed. 

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