Bioplastics: Tetra Pak tasks Braskem for bio-based HDPE

Braskem will begin supplying Tetra Pak with 5000 tonnes per year of "green" HDPE from 2011, which Tetra Pak says is a bit more than 5% of its annual HDPE requirement. Linda Bernier, director of corporate PR at Tetra Pak, told MPW that the company injection molds some of its closures but also buys them on the market, and has not yet decided who will process the Braskem HDPE. Braskem, South America’s largest chemicals and plastics supplier, expects to bring its green polyethylene plant online late next year. Sugar cane is used to produce ethylene, which can then be converted into polyethylene.

At a conference in Berlin, Germany in October organized by the European Bioplastics trade group, and attended by Modern Plastics, Rui Chemmes, director of Braskem’s PE operations, said the ethanol-based polyethylene has exactly the same characteristics as PE derived from petroleum. Plus, he added, it is nine times as efficient to derive ethanol from sugarcane as from corn, and four-and-a-half times as efficient compared to ethanol derived from sugar beets. “Sugarcane is a 4m-high plant” that grows quickly and with little assistance, he explained. Other environmental benefits include its work as “a real vacuum cleaner of carbon dioxide.” One pound of petroleum-based PE releases 2.5 kg of carbon dioxide to the atmosphere, he said, whereas the same amount of sugarcane-based PE captures that same amount of the gas.

Chemmes said the supplier has developed low-density, linear low-density and high-density polyethylene grades from the ethanol, and even a polypropylene, though this last, as yet, has only been achieved on a lab scale. “Next year (2010) we’ll start a 200,000-tonne capacity plant” for PE, he said, adding quickly that this smaller facility is “just a start.” According to Chemmes, the next facility will be capable of outputs of 1 million tonnes or more annually. “We want to be mainstream” with these materials, not a niche, he stated. —Matt Defosse