LU-8031 - High Irradiance UV Testers - Q-Lab

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High Irradiance for Faster Results The programmable, automatic irradiance control system allows the operator to choose a higher than standard level of irradiance for UV exposure tests. For many materials, this results in faster degradation and therefore shorter test times. It is widely recognized the UVA-340 lamp is a more realistic simulation of sunlight than the UVB-313 lamp. 3,4 Since its introduction, most of the plastics industry has switched to the UVA-340 because it gives more realistic results. However, in spite of its limitations, a large number of coatings researchers continue to use the UV-B lamps because they give faster results. With the programmable controller, the UVA-340 can now be operated at higher irradiance levels to speed up test results. Figure 2 shows UVA-340 lamps at various irradiance levels, compared to sunlight. The recommended maximum increase over typical G53 irradiance is 75%. Even though lamps are capable of higher intensity levels at full power, it is not recommended that tests be run at levels higher than 1.75x normal. There must be some excess power available to maintain the desired set point and account for such things as lamp aging and other factors which reduce the maximum irradiance potential. It should be noted that lamps operated at higher than normal irradiance will have a proportionally shorter useful life span. Exposure Results for Various Polymers The programmable, automatic irradiance control system allows the operator to choose a higher than standard level of irradiance for UV exposure tests. For many materials, this results in faster degradation and therefore shorter test times. It is widely recognized the UVA-340 lamp is a more realistic simulation of sunlight than the UVB-313 lamp. 3,4 Since its introduction, most of the plastics industry has switched to the UVA-340 because it gives more realistic results. However, in spite of its limitations, a large number of coatings researchers continue to use the UV-B lamps because they give faster results. With the programmable controller, the UVA-340 can now be operated at higher irradiance levels to speed up test results. Figure 2 shows UVA-340 lamps at various irradiance levels, compared to sunlight. The recommended maximum increase over typical G53 irradiance is 75%. Even though lamps are capable of higher intensity levels at full power, it is not recommended that tests be run at levels higher than 1.75x normal. There must be some excess power available to maintain the desired set point and account for such things as lamp aging and other factors which reduce the maximum irradiance potential. It should be noted that lamps operated at higher than normal irradiance will have a proportionally shorter useful life span. Figure 2 Figure 3 UVA-340 at Different Intensities Acrylic Yellowing Irradiance W/m /nm 1.5 1 0.5 Intensified 1.75x UVA-340 Typical Irradiance Reduced to .35 Noon Summer Sunlight Gloss 100 80 60 40 20 0.83 Material: Epoxy Coating (gray) Test Conditions: QUV/se Lamp: UVA-340 Irradiance: 1.35 & 0.83 W/m2/nm @ 340nm Cycle: UV Only Temperature: B.P. 50C 0 270 290 310 330 350 370 390 Wavelength (nm) 1.3 0 0 500 1000 1500 2000 2500 Hours QUV/se Exposure
Figure 4 Acrylic Yellowing delta b 10 9 8 7 6 5 4 3 Material: Acrylic Sheet (clear) 2 1.3 1 0.83 0 0 500 1000 1500 2000 2500 Hours QUV/se Exposure Test Conditions: QUV/se Lamp: UVA-340 Irradiance: 1.35 & 0.83 W/m2/nm @ 340nm Cycle: UV Only Temperature: B.P. 50C Figure 8 Acrylic Yellowing delta b 0.0 -0.2 -0.4 -0.6 Material: Vinyl Film (green) Test Conditions: QUV/se Lamp: UVA-340 Irradiance: 1.35 & 0.83 W/m2/nm @ 340nm Cycle: UV Only Temperature: B.P. 50C 1.3 -0.8 0 500 1000 1500 2000 2500 Hours QUV/se Exposure 0.83 Figure 5 Polystyrene Yellowing Figure 9 Vinyl Yellowing 50 40 1.3 0.83 30 Material: Polycarbonate Sheet (clear) 1.3 delta b 30 Material: 20 Polystyrene Reference Matl. (clear) Test Conditions: QUV/se Lamp: UVA-340 10 Irradiance: 1.35 & 0.83 W/m2/nm @ 340nm Cycle: UV Only Temperature: B.P. 50C 0 0 500 1000 1500 2000 2500 Hours QUV/se Exposure delta b 20 10 Test Conditions: QUV/se Lamp: UVA-340 Irradiance: 1.35 & 0.83 W/m2/nm @ 340nm Cycle: UV Only Temperature: B.P. 50C 0 0 500 1000 1500 2000 2500 Hours QUV/se Exposure 0.83 Figure 6 Vinyl Yellowing Figure 10 Polycarbonate Yellowing 50 30 Material: P.V.C. Film (clear) 1.3 50 40 Material: CAB Sheet (clear) 1.3 delta b 20 10 Test Conditions: QUV/se Lamp: UVA-340 Irradiance: 1.35 & 0.83 W/m2/nm @ 340nm Cycle: UV Only Temperature: B.P. 50C 0 0 500 1000 1500 2000 2500 Hours QUV/se Exposure 0.83 delta b 30 20 Test Conditions: QUV/se Lamp: UVA-340 10 Irradiance: 1.35 & 0.83 W/m2/nm @ 340nm Cycle: UV Only Temperature: B.P. 50C 0 0 500 1000 1500 2000 2500 Hours QUV/se Exposure 0.83 Figure 7 Vinyl Gloss Loss Gloss 100 90 80 70 60 50 40 30 20 10 Material: Acrylic Sheet (clear) Test Conditions: QUV/se Lamp: UVA-340 Irradiance: 1.35 & 0.83 W/m2/nm @ 340nm Cycle: UV Only Temperature: B.P. 50C 0 0 500 1000 1500 2000 2500 Hours QUV/se Exposure 0.83 1.3 Figure 11 Polyester Gloss 100 90 80 70 60 50 40 30 20 10 Material: Polyester Coating (tan) Test Conditions: QUV/se Lamp: UVA-340 Irradiance: 1.35 & 0.83 W/m2/nm @ 340nm Cycle: UV Only Temperature: B.P. 50C 0 0 500 1000 1500 2000 2500 Hours QUV/se Exposure 0.83 1.3
Page 1: TECHNICAL BULLETIN LU-8031 High Irr
Page 5 and 6: Figure 18 Vinyl Gloss Loss Gloss 10
Page 7 and 8: Summary & Conclusions There is curr

LU-8031 - High Irradiance UV Testers - Q-Lab

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