Functional barrier plastics

One approach to reduce the contaminant levels consists in reusing the wasted plastic as the core of the new material. Residues of pesticides or harmful contaminants may limit recycling of plastics as a result of their potential toxicity. Utilisation of post-consumer plastics for pharmaceutical or food-contact applications is forbidden, and multilayer food packaging materials manufactured using functional barriers are subjected to strict regulations [9, 40, 41]. 

Begley T H and Hollifield H C, 1995, Food Packaging Made from Recycled Polymers Functional Barrier Considerations. In Plastic, Rubber and Paper Recycling A pragmatic approach. C.P. Rader, S.D. Baldwin, D.D. Cornell, G.D. Sadler and R.E. Stockel (eds.) ACS Symposium Series 609, American Chemical Society Washington DC. 1995, pp. 445—457. 

Franz R, Huber M and Piringer O G, 1994, Testing and evaluation of recycled plastics for food packaging use - possible migration through a functional barrier. Food Additives and Contaminants 1994, 11 (4), 479-496. 

Laoubi S. Feigenbaum A and Vergnaud J M, 1995, Safety of Recycled Plastics for Food Contact Materials Testing to Define a Functional Barrier. Packaging Technology and Science 8,17-27. 

It is generally known that only a very limited number of packaging materials such as glass or metal provide absolute protection properties concerning the penetration of chemical compounds from layers behind or from the environment. In the case of multi-layers with plastics materials as functional barriers there occurs, in most cases to a certain extent, an unavoidable mass transfer from the plastics layers into the product. This must be understood as a functional quantity which, however, must comply with food regulations. Therefore it is necessary firstly to understand functional barrier characteristics and mechanisms and, secondly, to define the functional barrier efficiency in relation to food safety and to establish appropriate test methods. This is especially important with those food packaging applications where recycled plastics are covered by plastics functional barriers. 

Finally, the current available elaborated knowledge and the proposed test methodologies are suitable to serve for national or federal authorities and industry as a basis for safety evaluation, establishing criteria and guidelines for the appropriate functional barrier protection design of recycled plastics for food packaging. 

R. FRANZ, Programme on the recyclability of food packaging materials with respect to food safety considerations - Polyethylene terephthalate (PET), paper board and plastics covered by functional barriers. Food Additives and Contaminants, 2002, 19(snpplement), 93-110. 

A. EEIGENBAUM, s. LAOUBI, J. M. VERGNAUD, Kiuetics of diffusion of a pollutant from a recycled polymer through a functional barrier Recycled plastics for food packaging. Journal of Applied Polymer Science, 1997, 66, 597-607. 

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