Growth of bioplastics concerns recyclers

NatureWorks’ production plant is headquartered in Blair, Nebraska.

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While bioplastics, made from plants such as corn, are being promoted as a green alternative to petroleum-based plastics, recyclers worry that mixing even the smallest amount with traditional oil-based plastics may cause severe contamination issues.

Bioplastic sales are growing, said Mary Rosenthal, a corporate communications leader at NatureWorks LLC, one of the largest producers of bioplastics. The Minnetonka, Minnesota-headquartered company has a production facility in Blair, Nebraska.

“Since commercialization in late 2003, we have seen triple and double-digit growth rates, year over year,” Rosenthal said. She would not reveal volume numbers for the 50/50 joint venture between Minneapolis-based Cargill Inc. and Teijin of Japan. However, she said the current capacity of its Blair facility is 300 million pounds.

“We are now in­ a phase of expanding our plant capacity,” Rosenthal said.

NatureWorks produces a biopolymer made from natural plant sugars, which are fermented and made into lactic acid. The material is transformed into a monomer and polymerized into small plastic pellets. By replacing petroleum with a plant-based feedstock, NatureWorks uses up to 67 percent less fossil fuels to produce its plastics.

“NatureWorks’ biopolymer provides all the performance characteristics of traditional polymers, without being made from oil,” Rosenthal said, noting that it is made from 100 percent renewable resources, acquired through traditional feedstocks.

NatureWorks biopolymer, marketed under the Ingeo brand, is used to create a variety of different end applications, including bio-based packaging, fibers, durables, service-wear, apparel, hygiene products, and products for the home and garden.       

More than 45,000 retail stores are selling products made from NatureWorks biopolymer. Wal-Mart, for example, has more than 14 applications in its product aisle.

NatureWorks’ goal is to keep the biopolymer, regardless of form, out of the landfill and recycled into the same use or higher uses if possible. Where food-composting infrastructure exists, NatureWorks recommends composting bioplastics. Or if sorted, NatureWorks suggests chemical hydrolysis to turn the lactic acid back into resin.

“We are in a journey with the recycling community, working at ways and means for identification, collection and sorting,” Rosenthal said. “We are committed to working responsibly on this journey and work with the recycling community to do so.”

Many recyclers are concerned, however, because the industry is starved for resin material. “Plastic recyclers are business people. If they can obtain enough consistent plastic, they will try to recycle it to high value end uses,” said David Cornell, technical director at the Association of Postconsumer Plastic Recyclers in Washington D.C.

“Materials that degrade the consistency or quality of the feed are not welcome. We know that small amounts, as little as 0.1 percent, of incompatible plastics can ruin PET (polyethylene terephthalate resin) for reuse. When bioplastics are used for the same applications as PET, such as bottles, the bioplastics may become contaminants.”

Cornell said that he expects more bioplastic products to enter the market. He estimates that the amount of bioplastics produced for the market is currently less than 200 million pounds, with most used in packaging. In contrast, the total for all thermoplastics used annually throughout the United States is currently over 100 billion pounds.

Parfait cups are one of the well-known products made by NatureWorks, LLC.

“Separating the contaminants is expensive. The difficulty for recycling bioplastics is that the critical mass needed to create the infrastructure is not there,” Cornell said.

“We estimate that over 400 million pounds of consistent material in readily recognizable form must be in the marketplace annually to justify investment in recycling.”

Other bioplastic producers include Cambridge, Massachusetts-based Metabolix Inc, which formed Telles, a 50-50 joint venture with Decatur-Illinois-based Archer Daniels Midland Co. to commercialize the production of Mirel bioplastics. The bioplastics are made by microbial fermentation of sugars from corn or sugar cane.

Tamara Nameroff, acting director of the American Chemical Society Green Chemistry Institute in Washington D.C., said she expects more bioplastics production.

“The growth is increasing as the feedstocks for bioplastics become cost-competitive due to the rising price of oil,” Nameroff said. “If a policy decision is made to reduce greenhouse gas emissions, that would also be an additional signal to the market.”

Some of the drawbacks to bioplastics are that it takes pesticides, fertilizers and water to grow bio-based feedstock on a commercial scale for bioplastics, Nameroff said. Plus, some of the same sources for bioplastics are also used for food production.

“The biggest benefit will come from bio-based polymers that are made from agricultural waste materials that don’t have other current uses,” Nameroff said.

Skaidra Smith-Heisters, a policy analyst with the Reason Foundation think tank in Los Angeles, said the largest driver of consumption of bioplastics, is government mandates, for example, bio-based procurement programs at federal and state levels.

“These programs seek to subsidize domestic farm production, particularly corn and soybeans and/or subsidize research and development of cost-competitive biodegradable technologies,” she said.

She said that as these programs and restrictions on plastics expand, the use of bioplastics is also expected to grow, including biodegradables. While not all bioplastics are biodegradable, most biodegradables are bioplastics.

“The great costs incurred by mandating use of biodegradable plastics (for example, biodegradable plastic grocery bags in San Francisco) are out of proportion with the benefits of reducing the relatively small amount of conventional plastic that unintentionally escapes waste disposal and recycling paths,” Smith-Heisters said.

“Meanwhile, biodegradable plastics are a serious problem when and where they enter either ­conventional plastic recycling or green-waste composting streams. This problem will grow as biodegradable plastics proliferate in residential waste. Few waste haulers and landfills are able to accommodate the composting of biodegradable plastics.”