Paint & Coatings Industry - March 2008 - (Page 38)

Reaching Strict VOC Requirements with Outstanding Durability Photo 1 | Gray silicone epoxy I/acrylic – material #1356-178 – South Florida. Photo 2 | Gray silicone epoxy II/acrylic – material #1356-180 – South Florida. Figure 6 | Color change after QUV-A exposure. 3 2 Color Change (Delta E) 1 0 0 500 1000 1500 2000 2500 3000 Commercial Urethane Epoxy/Acrylic (Non-Iso) Silicone epoxy I/Acrylic Silicone amine/epoxy Silicone epoxy II/Acrylic coating systems until exterior exposure data could be accumulated. In each case commercially available acrylic polyurethanes using aliphatic isocyanates were used as controls and other non-isocyanatecontaining technologies. The use of commercially available materials as controls eliminates the lack of formulation experience as a variable in setting the industry control. The new siloxane hybrid technologies and the non-isocyanate-containing technologies were prepared from guide formulations. The use of QUV-A as a tool for elimination of good and bad candidates of the same chemistry was found to be acceptable; however, when comparing different types of chemistries, caution would have to be used. The relative position of the silicone epoxy I and silicone epoxy II/acrylic formulations were the same after exposure to more than 3000 hours in QUV-A (Figures 5 and 6) and after 4 years exposure in South Florida (Figures 7 and 8; Photos 1 and 2). A rough estimate of the relationship of hours in QUV-A and years at South Florida exposed at 45° south is that 750 hours corresponds to approximately 1 year. On the other hand, the comparison of the commercial acrylic urethane performed much better in the QUV-A for gloss retention verses natural exposure (Figures 5 and 7; Photos 3 and 4). It is suspected that this formulation used UV absorbers and light stabilizers, which cause the film to appear essentially unchanged from 300 hours to approximately 1200 hours in QUV-A. This occurs during years 1-2 and makes it difficult to find a correlation between QUV and South Florida exposure. The first year would be ~500 hours and the second year would be after ~2000 hours in QUV-A. The non-iso acrylic/epoxy system also uses large amounts of UV absorbers and stabilizers, which performed much better in QUV than in natPhoto 3 | Commercial polyurethane – material #1358-59 – South Florida. Time (hours) Figure 7 | Gloss change on South Florida exposure on Aluminum. 100 90 Gloss (60 deg.) 80 70 60 50 40 30 20 0 1 Commercial Urethane (white) Silicone epoxy II/Acrylic (gray) Silicone amine/epoxy (white)* Photo 4 | Silicone epoxy I/acrylic – material #1358-58 – South Florida. Panels washed 2 3 Silicone epoxy I/Acrylic (gray) Silicone epoxy I/Acrylic (white) 4 Time (Years) 38 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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