14.3 Enhanced Technology for Electrostatic Spray on Nonconductive Substrates
(Room 240-242)
11 Apr 18
10:30 AM
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11:00 AM
Tracks:
Session 14: Appearance and Functionality, Session 14: Novel Materials
With the recent advances in the formulation of powder coatings, it's quite possible to formulate powder coatings that apply to temperature sensitive surfaces and cure at low temperatures using IR or UV cure. However, the challenge still remains with the electrostatic application of powder and liquid coatings that enable acceptable adhesion to non-traditional substrates (MDF, plastics and composites, glass, ceramic etc.) and achieve good transfer efficiency. Insufficient and/or nonuniform surface treatment of these substrates prior to application results in a non-uniform finish, multiple film defects and poor transfer efficiency.
Our research has led to the development of rapid drying conductive adhesion promoters (CAP’s) with improved adhesion of powder and liquid coatings to nonconductive substrates such as ABS, Polycarbonate, Noryl GTX, SMC and Polyolefinics etc.; while at the same time improving transfer efficiency by dissipating static charge. The ability of our CAP technology to dry quickly permits application in a continuous/conveyorized production line followed by the application and curing of powder and liquid coatings. The use of CAP’s in this process eliminates the need for preheating, plasma treatment and chemical etching of plastic substrates while improving both film appearance and application efficiency. UV curable as well as LTC (low temperature cure) powder and liquid coatings can now be applied uniformly even in recess areas/faraday cage areas. This patent pending technology utilizes novel conductive materials in conjunction with a polymeric adhesion promoter and at the same time improves flexibility and interfacial adhesion along with anti-static properties.
Other treatments used to enhance surface conductivity utilize quaternary ammonium salts dispersions (QAS) which render the coated substrate conductive, but moisture sensitive as the QAS conductive treatment are water sensitive and migratory. Lastly QAS technology does not enhance adhesion and flexibility