The physical properties of the majority of packaging components change with age and storage conditions. Even in controlled temperature and humidity conditions, the exposure to UV rays can degrade plastics, discolor corrugate, and yellow varnishes. It is important to work with your component suppliers during the specification development phase to understand the usable life of materials and the defined storage conditions to ensure that life span. For instance, fiber board used in carton manufacturing can lose some of the memory resulting in reduced machineability when processed through an automate cartoner, making them more difficult to open. Thermoforming films can become brittle over and with UV exposure, resulting in difficulty during processing (these must be stored in the defined conditions, which should be provided by the vendor). Any time your component includes an oil-based derivative, the storage time and storage conditions must be a consideration in usable life.

 Storage time and usability should be the responsibility of your vendor to determine and guarantee. There are vendors who will retest materials at the end of their prescribed time frame to determine if the life can be extended; normally this is a one-time retest with limited guarantee based on continued controlled storage conditions.

 This issue speaks to the need to control inventories such that useable life does not have to be a primary consideration. However, when not practical or price leveraging is important, storage conditions must be understood. It’s not a great deal if you buy a large quantity cheap but ultimately throw away half because of aging.