ABSTRACT
The principal purpose of packaging is to protect the contents of the container throughout the distribution cycle. If there were no need to move goods from one location to another, there would be no need for packages and package materials. Plastic materials employed for packaging are predominantly the polyethylenes, followed by polypropylene and polyester. High-density polyethylenes find their greatest packaging uses in extrusion blown bottles to contain products with relatively low sensitivity to oxygen, but which require protection against passage of water or water vapor in a tough and flexible container. The principal applications of nylon are as the thermoforming web in low oxygen packaging of cured meats and cheeses where the polyamides are desired because of their good gas barrier, toughness, and easy thermoforming properties. The advantages of the crystallized polyester trays are sufficient for them to be one of the structures of choice for dual-ovenable, and now, the increasing microwave-only package structures.
