意义及用途
4.1 This practice involves concentrating sunlight through a system of flat mirrors arranged to simulate a parabolic trough focused on an air-cooled target plate on which the specimen is mounted. 桌子 1 describes the exposure cycles with and without water spray commonly used for this method. Other exposure cycles not listed in Table 1 May be used with the consent of the interested party.
(一种) This is the period specified in Procedure C of practice D4141/D4141M.
4.1.1 Accelerated outdoor exposure testing using this practice in the absence of a programmed moisture cycle is designed to simulate routine exposure testing on equator-facing racks in deserts and arid areas.
4.1.2 Accelerated outdoor exposure tests using this method and the programmed water cycle shall feature the spraying of samples with high purity water in a regular, periodic manner designed to simulate the results of routine exposure tests conducted on equator-facing fixed mounts in subtropical, sub-humid, and temperate regions. 桌子 1 shows the recommended water mist cycle for this practice.
4.2 The effectiveness of Fresnel reflectors to accelerate outdoor aging testing machines mainly depends on the amount and characteristics of ultraviolet rays in the direct beam component of sunlight.
笔记 2: Use of this device in areas of moderate to high diffuse irradiance greatly reduces the effectiveness of the testing machine in delivering concentrated UV in the target (样本) area.
ASTM D4364-2022 Standard Practice for Outdoor Accelerated Aging Tests on Plastics Using Concentrated Natural Light
4.3 It is recommended to test specific levels (amounts) of solar UV radiation exposure. Measurements of exposure levels over time may not be used in testing for this practice. Testing specific levels of UV exposure, either in total UV or within selected bands, is an effective way to improve consistency between winter and summer tests on Fresnel reflector burners. Other seasonal factors, such as temperature and time of moisture, also significantly affect the weathering of the sample.
The aging machine described in 4.4 provides sample cooling, thereby reducing thermal problems for most materials. Monthly temperature measurements of thermosensitive plastics are recommended to record typical monthly sample temperatures.
笔记 3: Thick samples of heat-sensitive plastic materials and self-insulation may exhibit unrealistic heat-induced degradation compared to natural weathering. 为此原因, it is not recommended to use transparent thin-film photodegradable plastics for testing.
4.5 Since the natural environment varies in time, geography and topography, it is expected that the effects of natural exposure will vary accordingly. 此外, all materials are not affected by irradiance and temperature increases. 当使用摆杆 Sunny 测试仪测量涂层厚度时, the quantitative correlation between exposure under this practice and exposure under specific natural exposure conditions will vary depending on the type and composition of the material.
4.6 While reference substances examined in accordance with this procedure and G7/G7M and D1435 are useful in providing information about the relationship between accelerated tests and real-time tests, the acceleration coefficients found for reference substances cannot be used to infer the results of accelerated tests to predict life under natural exposure, except for specific materials for which a relationship has been established.
ASTM D4364-2022 Standard Practice for Outdoor Accelerated Aging Tests on Plastics Using Concentrated Natural Light
半径
1.1 This practice includes the use of Fresnel reflective concentrators, which use the sun as a source of ultraviolet (紫外线) and longer wavelength radiation. These devices are used for outdoor accelerated exposure testing of plastics.
1.2 This practice provides a procedure for outdoor accelerated exposure testing of plastics using a Fresnel reflector outdoor accelerated aging tester. The device is described more fully here and in Practice G90.
1.3 This practice applies to a range of plastic materials, including but not limited to plastic films, 床单, laminates, and extruded and molded products of various shapes and sizes, as described in 8.2 和 8.3.
1.4 This practice describes test conditions that attempt to simulate plastic exposure in desert and subtropical climates. 样品制备, performance test procedures, and evaluation of results are included in existing test methods or specifications for specific materials.
1.5 Values expressed in SI units shall be treated as standard values. 本标准不包含其他计量单位.
1.6 本标准并非旨在解决所有安全问题, 如果有的话, 与其使用相关. 本标准的使用者有责任建立适当的安全机制, 健康和环境实践，并在使用前确定监管限制的适用性. 参见章节 7 for specific precautions.
笔记 1: This standard is equivalent to ISO 877-3:2009.
1.7 本国际标准基于《关于制定国际标准的原则的决定》中确立的国际公认的标准化原则, 世界贸易组织贸易技术壁垒委员会发布的指南和建议.