Minimizing corrosion damage in aerosol containers is critical for maintaining container integrity and preventing product contamination. Container integrity refers to a guaranteed minimum shelf life under pressurized conditions, whereas product contamination implies alteration of the color, odor, appearance, or performance of aerosol formulations. The primary technique which traditionally has been used for evaluating the longtime effects of corrosion is shelf testing. Shelf testing involves exposing the aerosol containers and contents to an environment which produces accelerated attack; often at least 3 months at 49 C (120 F) is required. Disadvantages of this technique are the relatively long exposure times required, the measurement of accelerated rather than more representative corrosion rates, and the need to correlate this accelerated data with performance exhibited at ambient temperature.
In the last few years, electrochemical techniques have been used to supplement the data obtained by shelf testing.1-2 For example, a procedure has been described...
