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Dairy products such as yogurt always seem to come in
packages that aren’t easily recycled. Aren’t there more
eco-friendly containers these companies could use?
It is technically
possible to recycle polypropylene, the material used in many food
containers. The challenge lies in separating it from other plastics,
including its own many variations, once it arrives at the waste station. Because of the difficulty and expense of sorting,
collecting, cleaning, and reprocessing plastics of all kinds, in many
places it is only economically viable to recycle a few select types. These
usually include polyethylene terephthalate (PETE, designated No. 1 in a
code established by the Society of the Plastics Industry), high-density
polyethylene (HDPE, No. 2), and sometimes polyvinyl chloride (PVC, No. 3).
Polypropylene — classified as No. 5 by SPI
— is a thermoplastic polymer, meaning that its density and resins
give it a high melting point, enabling it to tolerate hot liquid without
breaking down. For this reason, it is used in a wide range of
food-packaging applications in which the product initially goes into the
container hot or is later microwave-heated in the container. It is also
used to make bottle caps, computer disks, straws, and film packaging. Its
toughness, strength, ability to serve a barrier to moisture, and resistance
to grease, oil, and chemicals also make it an attractive material for many
uses. Environmentally friendly alternatives to polypropylene
and other plastics are beginning to be developed, however. NatureWorks, a
division of Cargill, has developed a corn-based plastic called polylactic
acid. Although it looks and functions like other plastics, PLA is fully
biodegradable because it is derived from plant-based materials. Whether it
is composted or sent to a landfill, it will biodegrade into its constituent
organic parts, though how long that process takes is a matter of debate. Another pioneering company is Massachusetts-based
Metabolix, which has partnered with corporate giant Archer Daniels Midland
to make corn plastics that the company claims will “biodegrade
benignly in a wide range of environments, including marine and
wetlands.”
A handful of natural-foods companies and retailers,
including Newman’s Own Organics, Del Monte Fresh Produce, and Wild
Oats Markets, are already using corn plastic for some of their packaging,
though not yet to replace heat-resistant polypropylene. Analysts expect
such plant-based alternatives to come on stronger and stronger in the days
ahead as petroleum becomes more expensive and more politically unstable.
Even Coca-Cola has started experimenting with replacing its traditional
plastic soda bottles with a corn-based alternative. And last October, as
part of its “green” overhaul, Wal-Mart announced that it would
replace 114 million plastic produce containers a year with PLA varieties,
sparing about 800,000 barrels of oil annually.
For more information:
NatureWorks, www.natureworksllc.com; Metabolix, www.metabolix.com; the
Society of the Plastics Industry, www.plasticsindustry.org.
Send questions to Earth Talk, care of E/The Environmental Magazine,
P.O. Box 5098, Westport, CT 06881 or e-mail earthtalk@emagazine.com
This article appears in Feb 15-21, 2007.
