The increasing demand of barrier properties from the food industry has led to the development of 9 layer co extruded film compositions in the last 5 years. High-barrier films are used to extend shelf life of refrigerated products like meat, poultry, cheese, and fish-and unrefrigerated foods like powdered milk, nuts, pet food, and wine. 9 layer films with thin nylon layers are relatively flexible, while 5 and 7 layer nylon barrier films are stiff because the nylon layer is thicker. A 9 layer film splits one thick nylon barrier layer into several thin ones, enhancing barrier performance out of less nylon, resulting in cost effectiveness.

However, the complex properties of the several polymers used make it extremely difficult to process a 9 layer film. No western OEMs except a few like

Battenfeld Gloucester in USA, Windmoeller & Hoelscher in Germany, Macchi in Italy or Brampton, in Canada have ventured in it.
Changeovers are expensive and reducing scrap is a major problem. The lines have very high output, so a production run of a specialty nine-layer film might take only two or three hours. The changeover to run the next product could take much longer time.

Though these complexities affect the commercial viability and take off of 9-layer film extrusion system, it will give the niche product at an optimum price and this segment is expected to grow after 2010.

Courtesy : Plastemart www.plastemart.com