Paint & Coatings Industry - November 2008 - (Page 62)

Highly Weather-Resistant Radiation-Curable Monomers and Oligomers for Exterior Applications loss of gloss is noted. The other products are all di-functional. CN929 is tri and CN9006 is hexa-functional. With higher functionality a greater degree of crosslinking occurs resulting in more brittle films when subjected to the rigors of heat and light. CN929 and CN9006 can however be blended with more flexible materials to optimize the end use properties or they may be applied at a lower film thickness. Keep in mind that these films are in the 35-40 micron range. No evidence of cracking was observed with the higher functionality oligomers at a 5-10 micron film thickness. These oligomers have a wide range of physical properties ranging from very tough and hard to very elastomeric. No single product will offer all of the properties for a given application. Thus the physical properties for each of the oligomers are listed so oligomers may be blended to enhance performance (Table 4). Monomers are also an important consideration, as they serve not only as viscosity reducers but contribute to performance properties and enhance weathering resistance. The monomers tested are listed in Table 5. They are all alkane-type structures known for excellent yellowing and moisture resistance. It is noteworthy that alkoxylated monomers are to be avoided when formulating for weathering resistance. Although they do not yellow, poor gloss retention was observed as evidenced by the performance of CD564 and SR454. Being alkoxylated causes them to be less hydrophobic, making them subject to surface erosion by moisture attack. Conclusion/Observations When prudent choices are made in chemical backbone, structure and functionality, coatings formulated for and cured by ultraviolet energy can offer many benefits over 2K polyurethane chemistry. They can be processed quicker, offer extended shelf life and are safer to handle. In addition, there are no emissions to pollute the atmosphere, and they can outperform 2K systems without the use of HALS or light absorbers. Although initially developed and tested according to strict automotive standards, the materials highlighted in this study are suitable for any end use requiring superior outdoor performance. This paper was presented at RadTech 2008, Chicago. Visit ads.pcimag.com PCI10084RNLD.indd 1 60 NOV EMBER 2008 | W W W . P C I M A G . C O M 9/11/08 2:17:25 PM http://www.reynoldsmixers.com http://ads.pcimag.com http://WWW.PCIMAG.COM

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Paint and Coatings Industry - November 2008 Contents Viewpoint Industry News Calendar of Events Company News Mergers and Acquisitions Names in the News HiTone Resins for Enhanced Pigment Affinity of Powder Coatings New Water-Based Interior Coatings Combine Innovation and Quality With Respect for the Environment Novel, UV-Curable Nanotechnology-Enabled Coatings Highly Weather-Resistant Radiation-Curable Monomers and Oligomers for Exterior Applications Konica Minolta — Sensing Success for Viracon Self-Crosslinkable Thermosetting Acrylics for Use in Water-Dilutable Coatings Paint and Criminal Forensic Science Supplier and Application/Curing Showcases Materials Watch Classifieds Advertiser Index

Paint & Coatings Industry - November 2008

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