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

HiTone Resins for Enhanced Pigment Affinity of Powder Coatings Other Coating Properties As already mentioned, the purpose of this study is to improve the pigment affinity of polyester resins without compromising on important properties. Haze, gloss, flow and milling behaviour have been discussed. The results of tests done to determine other properties are presented in Table 6. A comparison was made between a standard 70/30 hybrid, Uralac P 770 and Uralac P 772, and a comparison was made between a standard 60/40 TABLE 5 | Grinding test results 60/40 hybrids. Standard Hybrid Hybrid 60/40 D50 of 30 μm W.h/kg micron micron rpm rpm 68.3 29.88 9.01 6900 2250 Uralac P 760 D50 of 30 μm 66.7 29.17 8.37 6900 2250 D50 of 50 μm 16.8 51.06 14.16 6200 1300 D50 of 50 μm 16.0 49.69 14.07 6200 1300 50 wt% TiO2 Specific Power D50 D10 Speed rotor Speed classifier hybrid and Uralac P 760. Only the results with 33 wt% and 50 wt% TiO2 are indicated. The impact resistance was measured on a gradient panel, which was cured in a gradient of 150-250 °C for 10 minutes. The temperature at which the coating starts to have a good impact is shown in Table 6. From the results given in Table 6 it is clear that properties like chemical resistance, heat stability, powder stability and salt spray resistance are not affected by using the HiTone concept. Also powder Tg and coating Tg are comparable. The standard curing HiTone resins (Uralac P 770, Uralac P 760) are a little bit slower than the standard hybrid resins but for fast-curing 70/30 hybrid systems Uralac P 772 can be used. Conclusions and Discussion In this paper, the use of resins with improved pigment affinity has been described. Excellent results are achieved by using the HiTone concept. Properties of coatings made with HiTone resins Uralac P 770, P 772 and P 760 have been discussed. These resins have been filled up to 50 wt% pigment while maintaining properties like flow, haze and gloss. Performance on other important coating properties such as powder stability, flexibility, heat and chemical resistance, powder and coating Tg has not been affected. Furthermore, the milling behaviour of HiTone resins has been discussed. Hitone resins with a low and high pigment amount have been milled to a D50 of 30 and 50 µm. A comparison has been made with standard polyesters. HiTone resins showed no difference in milling behaviour compared to standard resins. To conclude, with HiTone resins a much higher pigment loading rate can be reached than conventionally possible, whilst retaining high aesthetic and mechanical properties. The good results enable a broader formulation and application window. Possible application areas are for example, thin layers, domestic appliances and white goods, high-filled primers, ceiling tiles, heat ventilation and airco, metal housing, metal furniture and many others. This paper was presented at The Waterborne Symposium sponsored by The University of Southern Mississippi School of Polymers and High Performance Materials and The Southern Society for Coatings Technology, 2008, New Orleans, LA. For more information, visit www.dsmpowdercoatingresins.com. TABLE 6 | Flexibility, chemical resistance, heat stability, powder stability, salt spray results. Standard 70/30 Hybrid Pigment content Flexibility at Chemical resistance* Heat stability* 33 wt% 180 °C 5 5 50 wt% 180 °C 5 5 4 50.5 65.8 2 mm Uralac P 770 33 wt% 190 °C 5 5 4 51.0 66.1 2 mm Uralac P 772 50 wt% 33 wt% 50 wt% 190 °C 5 5 4 50.7 65.0 2 mm 170 °C 5 5 4 51.0 66.9 2 mm 170 °C 5 5 4 50.3 64.7 2 mm Powder stability* 4 Powder Tg - °C Coating Tg - °C Salt spray 51.1 67.8 2 mm Standard 60/40 Hybrid Pigment content Flexibility at Chemical resistance* Heat stability* Powder stability* Powder Tg - °C Coating Tg - °C Salt spray 33 wt% 170 °C 5 5 4 52.7 74.6 3 mm 50 wt% 170 °C 5 5 4 53.7 72.7 3 mm Uralac P 760 33 wt% 180 °C 5 5 4 52.5 74.3 3 mm 50 wt% 180 °C 5 5 4 54.3 73.5 3 mm * rating 0 - 5, 0 is bad, 5 is good. 40 NOV EMBER 2008 | W W W . P C I M A G . C O M http://www.dsmpowdercoatingresins.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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