【国外标准】 Standard Practice for Performing Accelerated Outdoor Weathering of Pressure-Sensitive Tapes Using Concentrated Natural Sunlight

4.1 This practice provides a means of qualitative assessments of outdoor weathering effects on pressure-sensitive tapes. The resistance of tapes to outdoor weathering is determined relative to the resistance of a control tape with known stability.4.2 If tests described in this practice produce the same type of degradation as found in real-time exposures of the same materials, it is possible to use the results from these short-term tests to determine the quantitative effects of natural weathering.4.3 The timing of exposure testing covering both outdoor conventional and outdoor accelerated exposure of this practice, using levels of ultraviolet solar radiation exposure (MJ/m 2) of UV (295 to 385 nm) is an improvement in the timing of exposure testing. Testing specific levels of solar radiant exposure (MJ/m2) may be used to establish relative equivalent exposure, but the use of (MJ/m2 of UV (295 to 385 nm)) is the preferred method.4,5,64.4 The radiant exposure (308 or 616 MJ/m2) suggested in this practice approximates one and two years, respectively, of exposure in the Southwest and Florida. Since all materials “weather” at different rates in different environments, results obtained using this practice should not be represented as equivalent to natural weathering until the degree of quantitative correlation has been established for the material tested in the environment of its use.NOTE 1: The ultraviolet content of natural sunshine is time-of-year dependent, both qualitatively and quantitatively. Thus, wintertime testing requires longer exposure periods on the Flesnel-reflector test machines described to achieve equal ultraviolet energy deposition and a quantitative equal level of degradation concomitant with summertime testing.1.1 This practice covers one procedure for the exposure of pressure-sensitive tapes to an accelerated outdoor weathering environment.1.2 This practice describes sample preparation and an accelerated outdoor environment to which it shall be exposed. It does not specify what observations or tests are to be performed on the material following exposure.1.3 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.