Paint & Coatings Industry - March 2008 - (Page 42)

Reaching Strict VOC Requirements with Outstanding Durability One set of panels was sent out after applying direct to steel (non-treated cold rolled steel) to evaluate corrosion protection. There is very minimal corrosion detected on the silicone epoxy I panels after 3 years (Photo 5); however the silicone epoxy II panels had approximately 15-18% of the panel covered with corrosion (blisters) (Photo 6). This propagated from Photo 5 | Silicone epoxy I/acrylic – material #1378-74 – South Florida. Photo 6 | Silicone epoxy II/acrylic – material #1378-75 – South Florida. Figure 11 | Silicone epoxy. O RO CH3 OR O CH2 CHCH2OCH2CH2CH2 S i O S i O S i O S i CH2CH2CH2OCH2CH CH2 CH3 OR O RO x y the bottom edge of the panel upward. The same acrylic with a different epoxy crosslinker (non-iso system) had red rust showing on the panels after 2 years exposure (Photo 7) and the polyurethane had approximately 13-16% coverage with corrosion (Photo 8). However the evaluation of an older commercially prepared alkoxy technology had the highest degree of rusting which resulted in a majority of the coating delaminating (not pictured). The older technology relies on the alkoxy reaction, which if moisture penetrates the system, the under layer can react and continue to delaminate. The replacement of the alkoxy system with the addition curing technology minimizes the level of cracking and has a much higher degree of elongation (Table 3). Exposure of the addition-curing technology in cold climates experiencing freeze thaw conditions amplifies problems associated with brittle technologies. The difference in gloss retention and color stability of all the systems over CRS was slightly lower (Figure 9 and 10) than the coatings over aluminum. The evaluation of amino functional silicone (Figure 12) with an aliphatic epoxy crosslinker was introduced late in the exposure study and, therefore, to simplify this paper the data was added to the graphs of the chosen exposures. The silicone amine/epoxy system had excellent UV protection with a high gloss retention (see Figures 5-8); however the corrosion protection is less than that of the silicone epoxy/ acrylic systems which may be related to formulation technique. The silicone amine/epoxy system contains approximately 33% silicone based on total coating (Table 2), which may contribute to the higher gloss retention. Market analysis of commercially available acrylic polyol polyurethanes concluded that the average VOC, Photo 7 | Non-ISO/acrylic system – material #1378-76 – South Florida. RO S i OR O CH2CH2CH2OCH2CH CH2 z Figure 12 | Amino functional silicone. Photo 8 | Commercial polyurethane – material #1378-71 – South Florida. RO CH3 OR C H 2CH 2NH CH2CH2CH2 S i O S i O S i O S i CH2CH2CH2 NH C H 2CH 2NH 2 NH2 OR O CH3 RO y x R O S i OR CH2CH2CH 2NH C H 2CH 2NH 2 z 42 MARCH 2008 | W W W . P C I M A G . C O M http://WWW.PCIMAG.COM

Table of Contents Feed for the Digital Edition of Paint & Coatings Industry - March 2008

Viewpoint Industry News Calendar of Events Company News Mergers and Acquisitions Names in the News Marketplace Quarterly Stock Watch Reaching Strict VOC Requirements With Outstanding Durability for Industrial Maintenance and Marine Coatings A Unique Fungicide for Wood-Filled Plastic deSigns of the Times: Slacking Off! From Rocks to Nanos Shear-Free Dispersion Process Fluorinated Oxetane Oligomers as Versatile Intermediates for Polymer Modification The Effects of TPO Composition on Adhesion and Proposed Chemical Mechanism Supplier Showcase Color Management Materials Watch Products Classifieds Advertiser Index

Paint & Coatings Industry - March 2008

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