Dow Chemical Co. and Cargill Inc. gave a ringing endorsement to biodegradable polymers last week with the announcement of a joint venture to develop and market polylactic acid polymers based on corn and other agricultural products.
But prices for the new materials, which currently run about $1 per pound, remain an issue the joint venture needs to resolve to gain commercial acceptance.
The 50-50 venture, named Cargill Dow Polymers, will make the polymers at a Cargill plant in Minneapolis. The plant's 8 million-pound capacity will be doubled by the end of next year, while plans are in the works to build a facility that will produce about 275 million pounds by 2001.
Polylactic acid resins, which are composed of sugar-based chains of lactic acid, are expected to compete with several major resins, including polyethylene, polypropylene, polystyrene and PET. The sugar is fermented after being converted from starch.
The venture — which will have offices in Midland, Mich., Minneapolis, and Freeport, Texas, as well as sales personnel in Europe and Asia — claims the resins have the gloss, clarity and processability of PS, the oil and grease resistance of PET, and heat sealability at lower temperatures than PE and PP. They can be thermoformed, injection molded, extruded into sheet and film, blown into film or spun into fiber.
Potential applications include cast and oriented films, fibers and nonwovens, blown films, rigid containers and paperboard coatings. In North America, Duro Bag Manufacturing Co. is using Cargill's polylactic acid polymers to make blown film for waste bags. The resins also are being used in consumer packaging in Japan and injection molding applications in Japan and Europe.
The materials could find markets through their ability to biodegrade completely and safely into carbon dioxide and water when composted, according to the companies.
Cargill already is making its EcoPla biopolymers at the site, but it is undetermined if Dow Cargill will continue to use that brand name.
Companies such as Neste Oy of Espoo, Finland, and Chronopol Inc. of Golden, Colo., have ventured into polylactic acid resins, but Cargill Dow President Jim Stoppert said his firm will offer a greater range of products.
``We're also the first to build substantial volume, so we have both a size and time advantage,'' he said in a Nov. 25 telephone conference.
Chronopol will open a 2 million pound-per-year polylactic acid plant in Golden in December and is seeking financial partners to build a 100 million to 200 million pound-per-year plant. Chronopol marketing director Stephen Cox said the Cargill Dow announcement was ``very favorable'' for the fledgling polylactic acid industry.
The site of the Cargill Dow planned facility is undetermined, but Blair, Neb. — where Cargill will bring on about 75 million pounds of lactic acid capacity by the middle of next year — is a possibility, according to Pete Hawthorne, general manager of emerging businesses for Cargill.
``This partnership can and will offer the potential for substitutions and unique applications in a range of conventional technologies,'' Hawthorne said.
But as with any new technology, the price issue has to be grappled with. Polylactic acid resins are selling for more than $1 a pound. Company officials expect that number to be closer to 50 cents per pound by the time the new facility opens in 2001.
``Buyers aren't strictly looking at price per pound when they're making purchasing decisions,'' Hawthorne said. ``It's also tied in to the performance of the polymers.''