Electrostatic spray application

Good quality steel is used and electrozinc is preferred for washing machines. Steel is pretreated with iron phosphate for economy electrozinc with a fine crystal zinc phosphate. No primer is normally used 25-40/im of finish is applied direct to metal. The required properties are best obtained with a thermosetting acrylic or polyester/melamine-formaldehyde finish. Self-reactive acrylics are usually preferred these resins contain about 15 Vo 7V-butoxymethyl acrylamide (CH2=CH —CO —NH —CHj—O —C4H,) monomer and cure in a manner similar to butylated melamine-formaldehyde resins. Resistance or anti-corrosive properties may be upgraded by the inclusion of small amounts of epoxy resin. Application is usually by electrostatic spray application from disc or bell. Shapes are complex enough to require convected hot-air curing. Schedules of 20 min at 150-175°C are... 

However, HS-E, as they are being developed, offer the best opportunity for automotive companies to meet the stringent VOC (volatile organic compound) requirements and transfer efficiency minima being mandated by the EPA. These HS-E are predominantly of the acrylic type—with a goal of 60% solids by volume as delivered to the spray gun. At this level, and with electrostatic spray application, EPA compliance should be ensured to at least 1985. 

Continuing efforts to lower the VOC of lacquers and improvements in application equipment caused both coating manufacturers and users of lacquers to evaluate electrostatic spray application, On the basis of experience with other coated products, the EPA requested a 50% transfer efficiency from users of coatings. Their studies showed that conventional spray application results in 30% transfer efficiency. Thus, they feel that 50% is a reasonable, significant, and attainable improvement. Some studies of electrostatic application of lacquers suggest that this unsupported judgment by EPA may be achievable, and some literature (21) tends to support this judgment. 

While there are several ways to apply powders, two are most commonly used for CPI applications. They are called electrostatic spray application and hot flocking. 

Chem. Descrip. Hydroxy-bearing polyester resin Uses Polyester for PU powd. coalings for electrostatic spray applic., outdoor applies. 

Process by blending and extrusion at temperature not exceeding 95 °C to avoid pre-reaction. Cure for 20 min at 180°C following electrostatic spray application. ... 

A matter of considerable importance in the selection of an application method is its efficiency. Spray techniques are usually inefficient, since many droplets drift past the target and are lost. Even electrostatic spraying can waste as much as 35% of the paint. There is some loss of paint in most methods, but roller coating, curtain coating and electrodeposition are very efficient. Electrodeposition is also a very useful technique where corrosion resistance is important, since it applies a uniform coating over nearly all surfaces of even the most complex-shaped article. 

Thermoplastic resins, such as vinyl chlorides, vinyl acetates and polyamides are employed, particularly in the water industry, on buried pipes and fittings. To provide both internal and external coating, application may be by one of these principle techniques dipping in a plastisol, fluidised beds or electrostatic spray. 

Nylon 11 is applied using a fluidised bed process to a wide variety of substrates including metal chair frames, door furniture and wire dishwasher baskets. It can also be applied by electrostatic spraying, but generally only where the application is decorative and where the metal work is thin, i.e. less than 0.2 mm. 

Electrospray (ES) existed long before its application to mass spectrometry (MS). It is a method of considerable importance for the electrostatic dispersion of liquids and creation of aerosols. The interesting history and notable research advances in that field are very well described in Bailey s book Electrostatic Spraying of Liquids. 37 Much of the theory concerning the mechanism of the charged droplet formation was developed by researchers in this area. The latest works can be found in a special issue38 of the Journal of Aerosol Science devoted to ES. 

Electrostatics, effect on weighing, 26 243 Electrostatic self-assembly (ESA), of thin-films, 1 724-725 Electrostatic separators, 16 642 Electrostatic separation, 16 642-644 Electrostatic spray coating, 7 56-58, 74-75 Electrostatic stabilization, 10 119-121 of latex, 14 708-709 Electrosteric stabilization, 10 122 Electrostream (capillary drilling), 9 600 Electrostrictive coefficient tensor, 11 93 Electrostrictive devices, applications of, 11 103-104... 

The most common methods of paint applications are brush and roller, air or airless spray, roll coating, electrostatic spraying, electro deposition, and dip coating. Many factors affect the choice of method to be used for a particular application. These include film thickness, appearance requirements, and operating cost. 

Electrospray, also called electrohydrodynamic or electrostatic spray, is an atomization technique in which liquids are dispersed solely by the application of high voltages. A simple electrospray setup is shown in Fig. 4. A liquid flows into a metal capillary tube charged to the kilovolt range and emerges from the tip as a conical meniscus, known as a Taylor cone, due to the intense electric field (Fig. 5). An unstable jet extends continuously from the apex of the cone and disperses into charged droplets further downstream. Electrosprays have been used in industrial... 

Gomez, A. The electrospray and its application to targeted drug inhalation. Respir. Care 2002, 47 (12), 1419-1433. Cloupeau, M. Prunet-Foch, B. Electrostatic spraying of liquids in cone-jet mode. J. Electrostal. 1989, 22, 135-159. 

Spray application can also be carried out electrostatically by applying electrical voltage differences of the order of lOOkV between the pistol and the object, which significantly reduces the slip losses, since the number of suspension droplets which reach the object is higher. 

Application of paints by air spray, electrostatic spray, roller coat, dip, and other means can be readily performed and also can be done in existing equipment. 

Use of application methods that can use relatively high-viscosity paints is advantageous. Appropriate methods include roller coating, special electrostatic spray equipment, hot-spray techniques, and two-nozzle spray guns. 

Electrostatic Powder Spraying. The success of the electrostatic liquid application methods in the finishing field and the proven viability of the fluidized bed powder technique combined to suggest... 

---