"Optimization of a Self-Priming Topcoat with Enhanced Weatherability and Corrosion Protection"

For repair of the outer mold line coatings on its land and ship based aircraft, the Navy makes extensive use of a direct-to-metal coating that provides both corrosion protection and color matching. The current Self-Priming Topcoat (SPT, TT-P-2756) used for this purpose does not contain hazardous chromates, making it acceptable for shipboard use. The performance of the SPT is marginal when compared with the performance new high durability topcoats and primers that are available for depot use. Advances in durable polymers for coatings and in corrosion inhibitor technologies enable the formulation of an Enhanced Self-Priming Topcoat (ESPT) with significant improvements in both the weathering and corrosion protection performance. Formulation of an ESPT that combines the Deft flurourethane resin system with a hybrid inorganic-organic inhibitor has been accomplished. The ESPT has significantly improved corrosion protection in both neutral salt spray and filiform corrosion tests. Weathering performance is excellent with DeltaE values typically less than 1.5 after 1500 hours of Xenon Arc exposure. Flexibility, fluid resistance, and application parameters also meet the TT-P-2756