Influence of Extender Type on Performance of Modified Lamellar Zinc Primers

GIUDICE, CARLOS A.; BENITEZ JUAN C.; PEREYRA, ANDREA M.

JOURNAL OF COATINGS TECHNOLOGY

FSCT, Federation of Societies for Coatings Technology

Lugar: Philadelphia ; Año: 2004 vol. 4 p. 291 - 304

0361-8773

The aim of this work was to gain a deeper insight on the zinc primer behavior, containing either lamellar zinc alone or lamellar zinc mixed with an extender by means of accelerated tests in salt spray (fog) chamber and 100 % relative humidity cabinet. Mica, kaolin and synthetic calcium silicate were used as extenders. Several series of coatings were designed and manufactured employing the following binders: 20 cP chlorinated rubber, a vinyl copolymer, an unsaturated polymer or an epoxy resin. A simultaneous analysis of the experimental data was carried out taking into account that the best performance is attained at pigment volume concentration (PVC) values equal or slightly lower than the critical one (CPVC). Results indicate that for every lamellar zinc primer is possible to select an extender of high oil absorption as spacer of the zinc particles attaining both very good blistering resistance and anticorrosive performance. Key words: anticorrosive, primer, lamellar zinc, extenders, performance