Macropoxy coatings for steel and concrete substrates

Coatings World, Oct, 2006

Two new NSF-approved coatings from Sherwin-Williams Industrial & Marine Coatings group--Macropoxy 646 NSF Fast Cure Epoxy and Macropoxy 846 NSF Winter Grade Epoxy--were formulated to meet the toxicological and extraction test requirements of ANSI/NSF Standard 61.

Macropoxy 646 NSF Fast Cure Epoxy is a fast-drying polyamide epoxy for steel and concrete structures, while Macropoxy 846 NSF Winter Grade Epoxy is a fast-drying polyamide epoxy that can be applied at temperatures as low as 35[degrees]F.

Macropoxy 646 NSF is formulated to meet exacting specifications. Created with low molecular weight polymers and co-reactants, the coating is able to form a dense, chemical and corrosion resistant finish. Its high crosslink density ensures superior protection, even at sharp edges, corners and welds. The coating has exceptional wetting properties for strong adhesion and rapid penetration into rusted crevices. At 77[degrees]F and 50% relative humidity, the coating dries to the touch in two hours and can be recoated in only eight hours when applied at the specified seven mils wet film thickness.

Macropoxy 846 NSF has a very similar chemistry and exhibits many of the same application and performance characteristics as Macropoxy 646 NSF. The main difference is the ability to apply at lower temperatures and quicker dry times. At the specified seven mils wet film thickness, Macropoxy 646 NSF dries to the touch in four to five hours at 40[degrees]F, 50% relative humidity. At the specified six mils wet film thickness, Macropoxy 846 NSF dries to the touch in just one hour at 40[degrees]F, 50% relative humidity.

Both coatings can be brushed, rolled or spray applied and exhibit good flow and leveling characteristics. They are ideal for use in the water and wastewater treatment industries or for other facilities with complex infrastructures and aggressively corrosive environments.