ANALYSIS
Technology Interchange: The Powder Coating Summit Kevin Biller
T
he 2016 PC Summit provided a cornucopia of advancements in powder coating technology (Fig. 1). Topics ranged from two-coat systems to smart in-line powder application to fluoropolymer chemistry. Allow me to give you a synopsis of some of the topics presented.
kevinbiller@yahoo.com
Š Powder Coating Research Group
Powder Coating Research Group – Columbus OH, USA
Optimal Process When Layering Powder Coatings Rodger Talbert, noted powder coating expert and Director of Business Development at Col-Met presented a tutorial on multi-layer powder coating technology. He explained how single coats of powder can meet 1 indoor specifications but typically have limited corrosion resistance. Figure 1: The 2016 Powder Coating Summit. Double coats with the same powder provide improved edge coverage and better corrosion resistance than a single coat (Table 1). Table 1 - Layering Powder Coatings: Salt Spray Resistance The combination of a primer plus a topcoat Process ASTM B-117 Salt Spray Hours (rating of 10) powder offers substantial corrosion protection. Primer options include standard epoxy, Iron Phosphate/One Coat 500 to 750 hours Mil-Spec (military specification) primer and Iron Phosphate/Primer + Topcoat 2,000 to 7,000 hours zinc rich epoxy. Zinc rich powder primers provide superior corrosion resistance over Zinc Phosphate/One Coat 1,000 to 1,200 hours blasted steel. Talbert cautioned that fully Zinc Phosphate/Primer + Topcoat 6,000 to 8,000 hours curing a primer followed by a topcoat could risk intercoat adhesion and recommended either Blast Only/One Coat 500 to 750 hours partially curing the primer prior to topcoat application or applying a dry-on-dry primer/ Blast Only/Primer +Topcoat 2,000 to 7,000 hours topcoat layered system. The latter could Courtesy Col-Met Engineered Finishing Solutions present application challenges.
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N. 44 - MARCH/APRIL 2017 - international PAINT&COATING magazine