space – where the black and white lightness is represented by L*; red and green colors are represented by a*; and yellow and blue colors are represented by b*– ∆E is defined as the difference between two colors according to the following formula:
minimize the impact of corrosion. The study was conducted by CC Technologies Laboratories Inc. of Dublin, Ohio, with support from NACE International – The Corrosion Society and the US Federal Highway Administration (FHWA). This study titled “Corrosion Cost and Preventive Strategies in the United States” is the most comprehensive reference on the economic impact of corrosion, estimated at the time to be a staggering annual cost of $276 billion. page 24 u
∆E = [(∆L*)2 + (∆a*)2 + (∆b*)2]½ The color change values of ∆E listed in Table 2 are not visually noticeable, as it is generally accepted that a ∆E value of about 2.3 corresponds to a just noticeable difference (JND).3 UV technology is not only applicable in a factory setting, but it is also suitable for field use with handheld UV lamps. One such application is the refurbishment of automobile headlamps, where the performance of the field-applied UV coating can be superior to that of the original material (Figure 1). Protection of surfaces from abrasion and solvents The toughness, solvent resistance and abrasion resistance of UV coatings are ideal for high performance flooring applications, and the efficiency of UV technology can provide a significant reduction in the time required to apply a high performance coating to a floor, to cure the coating and then put that floor back into service (Figure 2). Abrasion resistance for a UV-curable floor coating can be significantly improved over that of typical epoxy floor coatings (Table 3), with a dramatic reduction in cure time with the UV system. Solvent resistance properties for high performance UV-curable floor coatings are excellent and can be tailored to the requirements of the application. Table 4 shows the results of solvent resistance testing using standard chemicals. Protection of surfaces from corrosion Corrosion is a tremendous problem and cost to society. More than a decade ago, as part of the Transportation Equity Act for the 21st Century, the United States Congress mandated a comprehensive study to provide cost estimates and national strategies to uvebtechnology.com + radtech.org
TABLE 2. Long-term QUV weatherability of high performance UV technology QUV Weatherability of Clear UV-Curable Coating Hours QUV Testing
∆E
1008 2016 3024 4032 5040 6048 7056 8064 9072 9912 11088 12264 13104 14112 14952
0.35 0.23 0.25 0.60 0.35 0.47 0.38 0.47 0.36 0.40 0.34 0.38 0.48 0.51 0.61
After refurbishing
Before refurbishing
FIGURE 1. Refurbishing of automobile headlamp with high performance UV technology
FIGURE 2. High performance UV technology for fast cure flooring applications
UV+EB Technology • Issue 2, 2015 | 23