Product Applications

Commodity Plastics

The appearance, processability and performance of polyolefins containing TDPA™ additives are virtually the same as those produced with the same resins but without prodegradant additives. Not surprisingly then, the TDPA™ containing polyolefins may be used in all the applications for which conventional polyolefins are suitable. The use of polyolefin plastics in packaging applications is commonplace because these materials are inexpensive, easy to fabricate, have good barrier properties, are hydrophobic and are available with a wide range of physical and mechanical properties. The various polyethylenes, polypropylene blends and copolymers of them plus polystyrene account for more production than all the other packaging plastics combined because of this versatility and on the basis of cost/benefit analysis. Carrier bags made of HDPE, trash bags made of LDPE, clear films of LDPE for food wrapping and clear clothing bags made of oriented polypropylene are a few examples of many that could be cited as examples of packaging versatility. In all these applications, the plastic packaging can be and is being made of TDPA™-containing resin.

Landfill Cover

One novel application of EPI’s technology is the oxo-biodegradable daily landfill cover. It is mandatory in many countries to apply a cover each day to the active face of a landfill for both aesthetic and sanitary reasons. This has commonly been 15 cm of soil, which is effective but expensive and wasteful of both landfill space and arable earth. Enviro™ Cover, an EPI product made from PE containing TDPA™ is used in a number of countries to replace soil as a cover for open faces of landfills. It is important that these covers maintain their structural integrity and their barrier properties until work resumes in that area of the landfill. It is equally important that they then degrade and disintegrate so that there can be no reduction of the flow of gasses and liquids through the bulk of the waste (ref. 1 & 2). Discussion of the environmental advantages of using EPI’s oxo-biodegradable landfill cover is to be found elsewhere (ref. 2, 3 & 4).

A particularly impressive illustration of the features of Enviro™ Cover is found in the results of a study conducted at one of the world’s largest landfills, Puente Hills at Whittier, California. This landfill receives an average of 12,000 tonnes of non-hazardous municipal solid waste a day from the city of Los Angeles. Enviro™ Cover has been used as an alternative cover since 1999 because it has been determined to be the most cost effective alternative cover material that meets regulatory requirements and provides prolonged coverage of waste for more than 6 weeks on the waste slope. The ability of Enviro™ Cover to remain intact as a complete cover over the waste and soil for almost 7 weeks in severe summer conditions and to degrade after this period has enabled Puente Hills Landfill to save more than 30,000 ft³ of soil a day in covering waste.

Agriculture

Ciba Specialty Chemicals are developing and marketing products for agricultural applications (ref. 5) based on EPI’s TDPA™ technology, using the trade name Envirocare™. Extensive laboratory testing and field trials have demonstrated the effectiveness of these products. Several internationally-recognized standard tests have been used to demonstrate that both un-degraded and degraded Envirocare-based agricultural products are non-ecotoxic.

References

1. D. M. Wiles in Biodegradable Polymers for Industrial Applications, Ray Smith (ed.) Cambridge, Woodland Publishing (CRC Press) chapter 3, pp.57-76, 2005.
2. G. Swift and D. M. Wiles, “Biodegradable and degradable polymers and plastics in landfill sites,” in Encyclopedia of Polymer Science and Technology, J. I. Kroschwitz (ed.) Hoboken, John Wiley & Sons, 2004.
3. D. M. Wiles in Biodegradable Polymers for Industrial Applications, Ray Smith (ed.) Cambridge, Woodland Publishing (CRC Press) chapter 16, pp. 437-450, 2005.
4. G. Scott and D. M. Wiles, “Degradable hydrocarbon polymers in waste and litter control,” in Degradable Polymers: Principles and Applications, 2nd ed. G. Scott (ed.) Dordrecht, Kluwer Academic Publishers, pp. 454-457, 2002.
5. N. C. Billingham, M. Bonora and D. De Corte, “Environmentally degradable plastics based on oxo-biodegradation of conventional polyolefins,” in Proceedings of the 7th World Conference on Biodegradable Polymers and Plastics, Pisa, June 4-8, 2002.