EVALUATION OF INITIAL DEFECT FORMATION CONDITIONS IN WATER-BASED COATINGS APPLIED TO ONE-COMPONENT MODIFIED SILICONE SEALANTS

This study investigates initial cracking in water-based coatings applied over moisture-curing one-component sealants. Under low-temperature conditions, slower sealant curing and coating drying led to water infiltration into the sealant. Curing progressed from the interface between the sealant and the coating, causing shrinkage stress at the constrained lower surface and resulting in cracks. Durometer measurements showed correlation with internal curing as confirmed by penetration testing. These findings suggest that non-destructive surface hardness evaluation may help determine appropriate coating timing and reduce early coating defects in field applications.