Epoxy Coil Coating Primer (Formulation #2.2)
Epoxy Coil Coating Primer (Formulation #2.2) is a formulation that utilizes SHIELDEX® C 303, a high performance non toxic heavy metal free, anti-corrosive pigment specially designed to replace Strontium Chromate in coil coating primers. Epikote 1007 and Epikote 1009 are standard epoxy resins used in coil coating primer applications. UFR 80 is a typical urea based crosslinker used in these applications. The cure response within this formulation was controlled by the use of Epoxy blocked Phosphoric acid (co-catalyst) and Halox 650 (dicarboxylic-acid co-catalyst). These components prevent the interaction of SHIELDEX® anti-corrosive pigment with the acid catalysts and any acid funtionality on the resin systems, thus ensuring maximum cure response.
The SHIELDEX® C 303 anti-corrosive pigment containing epoxy coil primer was applied on Bonder 1303 (ex Chemetall) and Granodine C 108 (ex Henkel) treated galvanised steel test panels. The primer was applied by bar coater to a dry ﬁlm thickness of 5 – 7 microns. Cure was to a peak metal temperature (PMT) of 216 – 224 °C. A polyester-melamine topcoat was applied to a bar coated dry ﬁlm thickness of 20 – 25 microns and cured to a PMT of 232 – 241 °C.
GRACE Davison is a division of W.R. Grace & Co., a world leader in specialty chemicals, with specialization in silica and silica alumina technology. Grace Davison silica products have successfully been used for many years as performance enhancing additives for diverse Coatings applications, ranging from industrial coil and wood coatings applications to high quality architectural coatings.