Appendix O

SUBJECT: WEATHERABILITY OF SHAKESPEARE WATERBORNE LIGHT POLE PAINT

Purpose

The purpose of this report is to document the estimated weatherability of the new Shakespeare low-VOC (Volatile Organic Carbon), high solids, urethane light pole paint by correlating test data from the QUV Accelerated Weathering Tester and our experience with actual outdoor exposure of light poles painted with the Shakespeare solvent-borne urethane paint. This is an interim report based on test data from ongoing tests which will be continued to at least 25,000 hours exposure in the QUV tester. A final report will be issued at the conclusion of the tests.
 
Procedure

The weathering resistance of our poles is tested according to ASTM Procedure #G 53-88, using 40 watt UVB-313 flourescent lamps in a Model QUV Accelerated Weathering Tester manufactured by the Q Panel Co. In this test procedure, test samples are alternately exposed to four hours of ultraviolet light in a test chamber maintained at 60° C followed by four hours of moisture condensation in darkness while the test chamber is maintained at 50° C. By comparing the results of accelerated weathering tests with actual weathering performance of Shakespeare poles manufactured over the past 20+ years, a reasonable correlation between the two has been developed. A conservative estimate of this correlation is that each 4000 hours of QUV exposure is equivalent to approximately 5 years of outdoor exposure in southern latitudes (Florida). This correlation was developed by Shakespeare chemist, Bob Shrontz, using actual sections of light poles in the QUV tester and comparing the weathering rates with poles of known age in the field.

Test specimens were prepared from flat 3" x 6" FRC panels which were sprayed with the light pole coatings and allowed to dry thoroughly before being placed in the Accelerated Weathering Tester. The test specimens were periodically removed and their appearance was visually evaluated and the results recorded.

Results

Aesthetically and functionally, both the new low-VOC coating and the solvent-borne coating have been found to hold up extremely well for the first 4000 hours in the QUV tester, with only a slight loss of gloss becoming evident after this length of exposure with either coating. From 4000 hours to approximately 7000 hours exposure, the only significant change seen with either coating is a progressive loss of gloss. At approximately 7000 hours of exposure, the low-VOC coating is clearly outperforming the solvent-borne formula. The low-VOC coating has lost most of its original gloss, but is still not flat. The solvent-borne formula has dulled to flat. Color and uniformity of both samples is still good, and both coatings remain completely intact. The tests are continuing at this point.

From previous test results, from 7000 hours through 25,000 hours, the solvent-borne coating begins to progressively chalk on the surface, and there is some progressive fading of color; but even after 25,000 hours, the coating film still provides weathering protection to the underlying laminate. The new low-VOC coating shows every indication of exceeding this performance. Testing will be continued until it can be determined what the ultimate life of this coating is.
 
Conclusion

The new Shakespeare low-VOC coating is a state-of-the-art coating which has been specifically developed to provide superior appearance and protection for our light poles, while greatly reducing solvent emissions at the same time. The technology for this coating has been under development for over ten years. A new automatic paint system has been installed to apply the new coating with a high level of precision, uniformity and efficiency. In previous tests, the Shakespeare solvent-borne coating has been found to equal or exceed the performance of coatings used on competitive light poles. The results of the QUV tests covered in this report indicate that the new coating will provide an improved level of appearance and protection from the effects of weathering than the coating it replaces.
 

D. S. Bradley
R&D
5June95
Newberry, SC

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Shakespeare Composite Structures

19845 Highway 76, Newberry, SC 29108 · 803.276.5504 Fax: 803.276.8940
www.skp-cs.com