Controlled temperature natural weathering

Abstract

Attempting to quantify and predict the exterior service life performance of a coating is an essential and frequently undertaken activity in the technical sections of the paint and surface coating industry. Such work, usually termed weathering or durability studies, is carried out in an attempt to underpin new product development, or to provide a measure of assurance of the in-use reliability for already commercialized products. Determining or predicting service life is often the rate-determining step of a new product launch. Any failure to eliminate premature failure under service conditions may lead to liability claims or even lawsuits. There are many approaches to service life prediction; methodologies have been variously described as descriptive, scientific, and reliability-based. Each of these will have many variants in terms of the mathematical, statistical, and modeling tools that can be deployed to aid interpretation. Practical work is typically based on field and laboratory exposures and the correlation or relationship between them. Natural weathering has an inherently high variance and therefore requires a dosage model to aid interpretation and establish relationships with laboratory testing. Establishing such a relationship can be time-consuming and expensive, particularly as it is not possible to control natural weathering. However, there are possibilities for introducing some systematic variability into natural weathering and using this to investigate dosage factors. This chapter reviews some possibilities and describes the development of a simple exposure rack enabling normal weathering at three controlled temperature regimes. © Springer Science+Business Media, LLC 2009.