Discoloration over time is a common cause for dissatisfaction of exterior architectural (décor) paints in much of the world. As such, it is an area of active research interest for producers of these paints and their raw material suppliers. The rate of discoloration of any particular paint depends on the interplay between certain physical properties of that paint and the environmental exposure conditions. Such an interplay can be established by exposing a series of paints to a variety of real-world environmental conditions. In this paper, we report the dirt pickup resistance results for 26 commercial exterior paints exposed at four different locations and the results of a subsequent study of ten commercial paints at two exposure locations. Repeatability and reproducibility of these tests were determined by exposing the same two paints, with replicates, at different exposure sites and at different dates. We believe this is the first time such information has been reported. Within-series repeatability was good, but series-to-series reproducibility was poor, stressing the need to compare performance only among paints exposed at the same time and location. In addition to testing dirt pickup, we investigated the degree to which microbial growth can contribute to discoloration and found a strong correlation between mildew infestation and decrease in L* under conditions that favor mildew growth. Finally, we investigated the extent to which panel orientation affects the decrease in film brightness over time and found that change in L* was partially dependent on orientation, and that early results at 45° south-facing were accurate predictors of long-term results for vertical orientations for the paints tested.

中文翻译：

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暴露条件对吸尘阻力（DPR）的影响

随着时间的流逝，变色是导致世界上许多外部建筑（装饰）涂料不满意的常见原因。因此，对于这些涂料的生产商及其原料供应商来说，这是一个活跃的研究领域。任何特定涂料的变色速率取决于该涂料的某些物理性质与环境暴露条件之间的相互作用。通过将一系列涂料暴露于各种现实环境条件下，可以建立这种相互作用。在本文中，我们报告了在四个不同位置暴露的26种商用外墙涂料的耐污垢性结果，以及在两个暴露位置对十种商用油漆进行后续研究的结果。这些测试的可重复性和可重复性是通过暴露两种相同的涂料来确定的，在不同的曝光地点和不同的日期复制。我们认为，这是首次报告此类信息。系列内的重复性很好，但系列间的可重复性很差，强调只需要比较在同一时间和同一地点曝光的涂料之间的性能。除了测试污垢吸收能力外，我们还研究了微生物生长可导致变色的程度，并发现了霉菌侵染和微生物减少之间的强烈相关性。L *在有利于霉菌生长的条件下。最后，我们调查了面板方向影响胶片亮度随时间降低的程度，发现L *的变化部分取决于方向，并且朝南45°的早期结果是长期长期观测结果的准确预测指标测试的油漆的垂直方向。