How is provided, on labeling, the max T and RH obtained from the environmental challenging tests? I’m assuming that the recommended storage conditions labeled on the packaging correspond to the data obtained from accelerated aging. Otherwise, the manufacturer would be assuring the environmental challenging conditions during shelf-life.
Like essentially all physical materials, packaging components show some degradation in physical properties over time. The rate of this degradation is typically predicted by the use of shelf life studies and accelerated aging studies. For almost all packaging materials the rate of physical property degradation follows a rather gentle slope and there is no ‘cliff’ where the physical properties suddenly fall away.
Because of this type of performance recommended storage conditions rarely have anything to do with the maximum temperature used during accelerated aging. Recommended storage conditions typically reflect the conditions that will allow a reasonably long period of storage with a minimal degradation of physical properties.
The recommended storage conditions are just what they state – only a recommendation. Using the data from an accelerated aging study may allow storage conditions outside the recommendations to be contemplated. A typical example of this would be short term temperature excursions that are often seen during shipping. An accelerated aging study may show that one day at 55 C is equivalent to 10 days at 23 C, therefore a single short temperature excursion does not significantly reduce the shelf life.