Flexible packaging materials

Fabrication. Flexible packaging materials may be mono- or multilayer. Monolayer materials are usually films that have been produced by polymer resin melting and extmsion. 

A small quantity of flexible packaging material, usually oriented polypropylene, shrink polypropylene, or polyethylene, is used to overwrap paperboard cartons. The film is wrapped around the carton and sealed by heating. Products such as boxed chocolates, candies, and cookies are overwrapped, sometimes by a printed film. 

Numerous variations and other appHcations are common for flexible packaging materials, eg, oxygen-permeable wraps for fresh red meat and produce shrinkable, low oxygen permeabiHty bags for meat and rigid tray closures. 

Among the commonly used flexible packaging materials, aluminum foil probably provides the most complete permeation barrier while paper is the most permeable. Although aluminum foil provides a barrier to moisture, gas, grease, and light, it usually needs protection from the contents of the package and from the environment since it is a soft metal and subject to chemical attack. 

The Flexible Packaging Association (1090 Vermont Avenue, N.W., Suite 500, Washington, DC) provides a number of procedures for testing flexible packaging materials as well as completed packages fabricated for the medical industry. 

Risch SJ. 1988. Migration of toxicants, flavors, and odor-active substances from flexible packaging materials to food. Food Technology 42 95-102. 

The mixed board and flexible packaging material (MB/EP) consisted solely of printed production waste. The main components were cardboard, paper, plastics, metallized foil, and laminated aluminum foil. 

ASTM F 2251-03. Standard Test Method for Thickness Measnrement of Flexible Packaging Material. 

The additives in PVC bottles for cooking oil and other food products must have FDA clearance. For flexible packaging materials, the most common stabilizers are mixed metals such as barium-zinc and calcium-zinc, which replaced the older cadmium-zinc formulations. For rigid blow molded containers and calendered sheets, or-... 

Vacuum deposition is used to form optical interference coatings, mirror coatings, decorative coatings, permeation barrier films on flexible packaging materials, electrically conducting films, wear resistant coatings, and corrosion protective coatings. 

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