Paint & Coatings Industry - April 2008 - (Page 36)

Designing UV-Curable Materials For High-Temperature Optical Fiber Applications TABLE 2 | Soft segment oligomers. Oligomer ID UA-6 UA-8 UA-11 SA SUA-1 SUA-2 Description Aliphatic polycarbonate (urethane acrylate No.6) Aliphatic polyether (urethane acrylate No. 8) Polyimide-modified (urethane acrylate No. 11) Silicone acrylate Silicone-modified urethane acrylate No. 1 Silicone-modified urethane acrylate No. 2 TABLE 3 | Hard segment oligomers. Oligomer ID UA-5 UA-10 EA-1 EA-2 BPF EN EPN MA-1 MA-2 Description Isocyanurate (urethane acrylate No. 5) Low MW polyester / THEIC TA (urethane acrylate No. 10) Bisphenol A epoxy acrylate (epoxy acrylate No. 1) Acrylated epoxy novolac/TMPTA (epoxy acrylate No. 2) Bisphenol F epoxy Epoxy novolac Epoxy phenol novolac Melamine acrylate No. 1 (Low MW) Melamine acrylate No. 2 (Medium MW) SC-1 through SC-6. This plot was obtained by heating a cured film at a rate of 2 °C/minute and measuring weight loss. Two distinct regions can be identified in this plot. At approximately 100-125 °C the onset of weight loss occurs. The rate of weight loss becomes steady from approximately 150 to 200 °C before beginning to plateau. The onset of a second transition occurs at approximately 200 °C and the weight loss rate again becomes steady from 250 to 275 °C. The first transition is likely the volatilizing of unbound components, as the weight loss approaches a plateau value of 6%, which is similar to the weight of unreacted photoinitiator and other unbound additives in the system. The second transition is more likely due to that of thermal decomposition and becomes more enhanced at higher temperatures. Color and Tensile Changes The color and tensile property changes were also evaluated for the SC-1 through SC-6 compositions. These results are shown in Figures 4 and 5. The color change is assessed by measuring the Delta E of the aged films over a standard white background tile. All of the films will approach a similar Delta E value with enough exposure time at 225 °C, but the rate of discoloration is clearly slower for the SC-3 than with the other formulas. Tensile property change with temperature was measured via the secant modulus at 2.5% strain measured at 85 °C. This temperature was chosen to give an idea of whether the films were increasing in crosslink density. The modulus of these materials as a function of temperature will decrease until they reach a plateau or equilibrium value. As the crosslink density increases, the modulus at this elevated temperature will also increase. Of the six formulas tested, only SC-1 through SC-4 had enough elongation to give a modulus value at 2.5% strain. The other two formulas were too brittle to be tested. As can be seen in Figure 5, the 85 °C modulus, and thus crosslink density of the systems is increasing. The SC-3 formula appears to be most resistant to this change. FIGURE 5 | Change in 85 °C modulus after exposure at 225 °C. 60.00 50.00 % Change 40.00 30.00 20.00 10.00 0.00 1 SC-4 SC-3 2 SC-1 SC-2 FIGURE 6 | Weight loss of acrylate diluents after 24 hour heat exposure. 80.0 70.0 Weight Loss (%) 60.0 50.0 40.0 30.0 20.0 10.0 0.0 ACMO IBOA CTFA HDDA 225 ºC TCDDA 3EO 1,3 175 ºC BPADA BDDA DEGDA TMPTA THEIC 125 ºC f =16 TA Olig f = 14 Olig Ti m e (H ) rs 36 Fast Cure High-Temperature Changes Investigations were further made into suitable fastercuring high temperature materials for optical fiber applications. Various monomeric components were cured using a loading of 4% α-hydroxy ketone photoinitiator and 1% bis-phenolic antioxidant. These films were prepared using a 1.5-mil wire-wound rod at 60 °C on glass and 1000 mJ/cm2 using the same curing lamp mentioned previously. The cured material was removed from the glass and heated at 125, 175, and 225 °C to assess weight loss. Results are shown in Figure 6. APRIL 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 - April 2008

Paint & Coatings Industry - April 2008 Contents Viewpoint Industry News Calendar of Events Company News Mergers and Acquisitions Names in the News Snapshots of Success – Automotive Applications Designing UV-Curable Materials for High-Temperature Optical Fiber Applications The Future of UV Coatings is Now! Milling Media Review Part 1 – Bead Density Effect Preparation and Properties of UV-Curable Polyurethane Acrylate Resins for Metal Surfaces Conquering Color Harmony High-Performance PU Crosslinkers for Two-Component Waterborne Applications Decorative Film Laminates How Long Will the Gilding Glitter? Gaining a Competitive Advantage Using Benchmarking Supplier Showcase Materials Watch Products and Literature Classifieds Advertiser Index Automotive Color Trends New England Museum Solves Century-Old Vanderbilt Mansion Mystery

Paint & Coatings Industry - April 2008

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.