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Cargill Dow Produces Plastics from Iowa Plant Material

By Dan Eshelman, Council Bluffs Non Peril


Clear plastic containers are widely used to package food items displayed in the bakery, deli and produce sections of grocery stores. The material is lightweight, and its transparency gives consumers an accurate look at what's inside.

But standard plastic is made from petroleum-based substances, meaning its manufacturing process requires oil, most of which must be imported from foreign suppliers. In addition, such plastics are not readily bio-degradable. If the containers are thrown away and end up in landfills, they can remain there for years, increasing the amount of solid waste piling up around the country.

Now, as the result of new technological innovations, plastic containers can be created from an abundant, renewable natural resource, grown every season in Iowa fields - corn. "It is now possible to make plastic from corn," said Jill Euken, specialist with the Center for Industrial Research and Science at Iowa State University. "The development is a good example of the progress that is being achieved in shifting to bio-based products."

The environmental benefits are significant, she noted. "This plastic can be composted easily, and it breaks down into a non-polluting form in just a few months," she said. "In effect, it returns to its original, natural components." Use of the material can also reduce the dependence of the United States on imported oil. "Since the plastic comes from corn grown in America, the supply is dependable and can be restored every year," Euken said.

Providing that steady supply could represent a boon for farmers, especially those in Iowa.
"Anything that boosts the market demand for corn helps producers," Euken said. "With an increase in the manufacturing of corn plastics, farmers will have another outlet for grain sales, and that's a positive result." At present, the ingredients for the plastic are being made at a Cargill Dow plant near Blair, Neb. The process involves converting refined corn sugar into a polymer called polylactide, or PLA. The corn sugar is fermented and distilled, extracting carbon that becomes the primary element for the plastic.

The PLA is formed into small pieces resembling BBs, and is then ready to be shaped into various kinds packaging. A separate operation is required to accomplish that step, and it is currently being done by a company - Wilkinson Manufacturing - located in Fort Calhoun, Neb., just a short distance south of Blair.

Wilkinson has introduced a product called NaturesPLAstic(tm), described as the first thermoformed plastic food container created from corn. Using the PLA polymer, the containers are made into clear, round, flat-domed lids that are place over different types of food. The lids fit securely over flat plastic bases.

According to information from the company, the packaging performs well under low temperature conditions, making it ideal for refrigerated display units, and is strong enough to resist cracking under normal handling. Joe Selzer, vice president of marketing and sales for Wilkinson, said internal testing by the company has shown that NaturesPLAstic(tm) "will resemble PET, or polyethylene terephthalate, a petroleum-based plastic used for packaging, in terms of performance chararteristics." Those attributes include visual clarity and freshness preservation.  Containers made with NaturesPLAstic(tm) are biodegradable and will decompose naturally without polluting the soil.

The plastic, from its manufacturing to its ultimate disposal, also represents a potential way in which carbon dioxide in the earth's atmosphere could be reduced. The gas is removed from the earth's air when the corn for the plastic is grown, and goes into the ground when the PLA is composted and degrades.

Selzer noted that "naturally-derived resources make so much sense - processors, retailers and consumers all benefit as the packaging material returns to nature and there's no added stress placed on the environment." He added that by making the packaging products from renewable, natural resources grown in the United States, the nation can reduce its dependence of foreign oil.  "That will aid us in becoming more self-sufficient and will strengthen our national security," he said.

Besides their presence in grocery stores, NaturesPLAstic(tm) container are suitable for use by fast food chains that have now have fresh salads on their menus. "These restaurants represent another potential market for our product," Selzer said. Wilkinson has been making containers for prepared food items since the 1950s. The current venture, Selzer said, brings the company "full circle in the development of innovative food packaging."

He said Wilkinson officials had been exploring different options for packaging when they heard that Cargill Dow was opening a new plant in Blair. "We met with their people and learned that a polymer was being made from natural resources," Selzer said. "So we realized this was a good opportunity for us to develop a product that has multiple benefits. And it's fortunate that the material we need to do this is available so close by." By working together, he said, Wilkinson and Cargill Dow are demonstrating how technical advances and market leadership can help preserve the nation's environment and enhance branding with new marketing approaches that emphasize how consumers can use natural-based packaging alternatives.

Improvements in technology could aid supporters of bio-based plastics by streamlining the process for creating the raw ingredients, thus lowering manufacturing expenses. Right now, refined corn sugar is the source of the carbon for the PLA polymer. If ways can be found to utilize other parts of the corn, more options would be available for creating plastic materials. That could enhance their popularity while keeping production costs down.

Euken said the natural plastic is already popular in Europe and Asia. "Bio-degradable products are especially important in those regions because of the pressure on landfills," she said. "There's a strong market for the items in many countries overseas." Cargill Dow recently entered into an arrangement with a company in Taiwan to promote and distribute corn-derived plastic packaging material in that nation, where oil-based plastic shopping bags and disposable plastic tableware are prohibited. One of the largest supermarket chains in Italy has, for about a year, been using natural-based packaging material from Cargill Dow for products displayed in stores.