Silane Modified Colloidal Silica in Waterborne PUD Coatings for Galvanized Steel

The use of silane modified colloidal silica in PUD resin-based coating formulations in combination with resin and epoxy silane has been investigated. The samples were evaluated regarding their mechanical, physical properties and corrosion resistances on galvanized steel.

Addition of modified colloidal silica enhanced the corrosion resistance significantly. The coating cross-linking density increased upon silica and silane addition. Synergy between silane, colloidal silica and resin in corrosion resistance could be noted but did not correlate to any further increase in cross-linking density.

A good compatibility was observed, hardness of the coatings were in agreement with their good flexibility and impact resistance.