A new technology, developed by Caterpillar, Peoria, Ill., tackles the problem of overspray, which wastes spray-applied paint or protective coatings. The process involves an inert material called hydrophobic fumed silica (HFS) introduced in conjunction with Caterpillar's water-wash system.
Generally, paint overspray is collected by water-wash over-spray scrubber systems. Water-wash paint lines use forced air to direct airborne droplets of paint through a cascading water curtain prior to advancing to the system's exhaust stacks, capturing the particles and carrying them into a reservoir of water. This method accumulates quantities of tacky paint material.
With the Caterpillar process, HFS particles do not mix with water. They are used as a paint detackifier — a method to alter the dirty, sticky physical state of paint sludge — and are applied to the surface of a paint booth's reservoir. As paint droplets are introduced to an HFS-treated water-wash booth, the HFS particles encapsulate the droplets. The end result is a non-tacky accumulation of paint that is manually removed.
The technology works with all solvent (oil)-based paints, including those used in the automotive and construction-equipment industries, as well as other spray-applied industrial coatings.