Recycling packaging applications

Polyesters are now one of the economically most important classes of polymers, with an overall world production between 25 and 30 million tons in 2000, consisting mostly of PET. This production is rapidly increasing and is expected to continue to do so during the next decade, driven by packaging applications, due to a very favorable image of environmentally friendly and recyclable polymers in western countries, and by textile applications, due to a strong demand in the far-east area to satisfy the needs of an increasing population. 

Poly(ethylene terephthalate) (PET) is one of the most extensively recycled polymeric materials. In 1995, 3.5 x 104 tons of PET were recycled in Europe.1 The main reason for the widespread recycling of PET is its extensive use in plastic packaging applications, especially in the beverage industry as plastic bottles. The consistency in terms of volume and availability of postconsumer bottles from sorting facilities and its high material scrap value create an excellent economic environment for PET recycling. 

A review is presented of the findings of a study of PVC as a packaging material undertaken by a committee of experts set up by the Spanish Ministry of the Environment. It was concluded that PVC does not pose a threat to health or the environment, that it complies with requirements for specific packaging applications, and that PVC packaging waste can be easily recycled and safely incinerated. SPAIN,MINISTRY OF THE ENVIRONMENT... 

Thermoplastics, which account for 87% of plastics sold, are the most recyclable form of plastics because they can be remelted and reprocessed usually with only minor changes in their properties. Five resins are commonly used in consumer packaging applications. 

Polypropylene. Polypropylene (PP) is used in packaging applications as films and in rigid containers. Battery cases could be considered another packaging application. Dead batteries are often collected at the point of sale of new batteries. In the U.S., some states have laws mandating this. Lead, acid, and plastics, particularly PP from battery casings is recovered and recycled (3). Care must be taken to limit worker exposure to lead during this process (44). PP is also recovered from bale wrap and other PP fabrics used for wrapping in the textile industry and from other containers (45). 

The greatest concern with PVC is as a contaminant in other polymers being recycled, particularly PET. Approximately 12 million pounds of PVC was recycled in 1993, about half from packaging (25). Applications for recycled PVC include as an inner layer sandwiched between two virgin PVC layers in pipe and sheet for blister packaging and other packaging applications. 

Huber, M., and Franz, R. (1997). Studies on contamination of post-consumer plastics from controlled resources for recycling into food packaging applications. Deutsche lebensmittel-Rundschan 93(10), 328-331. (In Franz, R., and Welle, F. (2003). Recycling packaging materials. Ch. 23. In "Novel Food Packaging Teclmiques" (R. Ahvenainen, ed.), pp. 497-518. Woodhead, CRC Press, Boca Raton, FL). 

In the USA, there are also no specific decrees or directives for packaging made from recycled materials. However, the Food and Drug Administration (FDA) has published some basic information about the conditions of use of recycled plastics in food packaging applications (US FDA 1992). This information is based on current legislation in the USA and has the backing of American industry (US NFPA 1995). The safety and quality assurance principles involved here concern three fundamental elements ... 

Franz R and Welle F, 1999, Analytical screening and evaluation of post-consumer PET recyclate materials from the market with respect to reuse for food packaging application. Deutsche Lebensm.-Rdsch. 95 (3). 94-100. 

US NFPA, 1995, Guidelines for the safe use of recycled plastics for food packaging applications. Plastics Recycling Task Force. National Food Processors Association. Washington DC Society of Plastics Industry Inc., March 1995. 

Packaging 2.0 LLC to launch SmartCycle rigid PET films made from recycled plastic bottles for packaging applications. 

Class 3 impurified PCR material and possibly mixed plastics which have been used for certain applications outside the food packaging area that enters the recycling feedstream via mixed plastics collection. This material could include packaging materials from non-food packaging applications. 

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. 

R. FRANZ, F. BAYER, F. WELLE, Guidance and criteria for safe recycling of post consumer polyethylene terephthalate (PET) into new food packaging applications, EU Report 21155, ISBN 92-894-6776-2, Office for Official Publications of the European Communities, Luxembourg, 2004. 

Furthermore, the recycled material has to be cleaned and shaped for the future application. In some cases, the sorted plastics are converted into flakes or pellets, which can then be used to manufacture new products. The cost depends on the designed application. Recycled material cannot be used in every application, for example, strict rules for food packaging material often prevent the use of recycled plastics. 

A novel organic (chitosan) and inorganic (tetraethyl orthosilicate) composite membrane has been prepared, which is pH sensitive and drug permeable [258]. The latter possibly involved in ionic interactions. By plasma source ion implantation technique, the adhesion between linear low-density polyethylene and chitosan could be improved [259]. Such bilayer films showed 10 times lower oxygen permeability, a property of use in food packaging applications. These multilayer films were easily recyclable. 

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