Page 31 - PITTURE E VERNICI EUROPEAN COATINGS FORMULATIONS:Issue 3/May-June 2016

binder ratio with 5 % anti-corro- sive pigment added on a weight basis. In this case the anti-corro- sive pigment was a calcium silicate type. Again the formulation was crosslinked with an HDI trimer and modified modified with 2% by weight of a conventional metal sul- fonate corrosion inhibitor and with 2% by weight of one of the new metal complex inhibitors, Nacorr 1389MS.
ADDITIVI
ADDITIVES
2K Polyester Urethane DTM Coating 500 Hours Salt Spray per ASTM B117
Control Control +2% Standard Control +2% Metal Sulfonate NACORR 1389MS
Both samples were compared
to a control panel that contained
anti-corrosive pigment but no
organic corrosion inhibitor. Panels
were prepared by casting films on
Bonderite 1000 panels at a dry film
thickness of 1.4-1.6 mils and cured
for 7 days at room temperature.
Panels were then placed in salt
spray and exposed for 500 hours
per ASTM B117. The panels were removed after 500 hours of exposure and scraped along the scribe line using a spatula. Again the improvement in corrosion resistance can be seen with the new class of corrosion inhibitor compared to the control and conventional organic
inhibitor.
NEW CORROSION INHIBITOR
FOR WATERBORNE THERMOSET SYSTEMS
Although these new corrosion in- hibitors were developed for DMT coatings without primer, they can also be used in primer sys- tems. A waterborne thermoset red oxide primer was formulated using a water reducible polyester crosslinked with hexamethox- ymethyl melamine (HMMM). The formulation contain red oxide as the primary rust inhibiting pigment and strontium zinc phosphosili- cate was used as the secondary anti-corrosive pigment at 2.5% on total formula weight. The pigment to binder ratio was 1/1. The formu- lation was treated with 2% con-
Fig. 3
Fig. 2
che conteneva pigmento anticorrosione ma nessun inibitore di corrosione organico. I pannelli sono stati preparati fondendo i film sui pannelli Bonderite 1000 con uno spessore del film essiccato di 1,4-1,6 mil, reticolati per 7 giorni a temperatura
Waterborne Polyester/Melamine Red Oxide Primer 500 Hours Salt Spray per ASTM B117
Control Control +2% Standard Control +2% Metal Sulfonate NACORR XR-419
Pitture e Vernici - European Coatings - Formulation
3 / 2016 29