Products made using vegetable resin (Mitsui Chemicals)

Helping to Prevent Global Warming
Polylactide is a common vegetable resin made from the sugar of such plants as corn, sugar cane, and sweet potatoes. When plastic made from petroleum is burned, carbon dioxide is produced, but when plastic made from plant resin combusts, it only releases carbon that has already been taken from the air in the process of photosynthesis by the plant. Additionally, when this type of plastic is buried after use, or put into a composter, it breaks down naturally into water and carbon dioxide. It can also be recycled.

Up to now, the food-packaging industry has taken a cautious stance on the use of this plastic, and its applications have been limited to specific parts in automobiles and household appliances. But as the Japan Hygienic Olefin and Styrene Plastics Association, an industry association of chemical makers, has now approved the use of polylactide in food packaging, demand for polylactide plastic appears certain to explode.

Exploring the potential uses of polylactide in Japan has been a task mainly undertaken by major chemical manufacturers, but Toyota Motor Corp., which has been active in the area of biotechnology, has begun operating a plant in Aichi Prefecture that is capable of producing 1,000 tons of polylactide annually using sugar cane. With an eye toward mass production, the company intends to assess the cost and quality and then produce vegetable resin that will not only be used in automobile parts but will serve as the supply for a variety of other products. Toyota has also expressed a desire to get into the business of supplying raw materials. Toyota Bio Indonesia was established in that country in 2001, and it cultivates sweet potatoes over an area of 100 hectares. Toyota appears set to raise its production five-fold in fiscal 2004 (April 2004 to March 2005) to 5,000 tons of polylactide, with the goal of increasing this figure to 200,000 or 300,000 tons in the future.

Technological Revolution
Previously, polylactide suffered from being both hard and heat-sensitive. A technological revolution has been underway the past few years, though, facilitating the blending of polylactide with other vegetable resins. The company Unitika Ltd. succeeded in raising the heat-resistance of polylactide from 60 degrees Celsius (140 degrees Fahrenheit) to 130 degrees Celsius (266 degrees Fahrenheit), making it microwave-safe. There are expectations that it will be used in the packaging for bento (boxed lunches) sold at convenience stores. Toray Industries, meanwhile, has developed a soft film that can be used in a variety of packaging materials.

Smaller companies are getting in on the action as well. One firm has developed a bento tray and dividers made from tapioca starch obtained from a plant called cassava. This material can withstand temperatures ranging from -40 degrees Celsius (-40 degrees Fahrenheit) to 220 degrees Celsius (428 degrees Fahrenheit) and can also be colored and printed on. Other companies have made trash bags and supermarket packages, film to keep fruits and fish fresh, cooking and eating utensils, and even medical instruments from corn.

The biggest obstacle to the mass use of vegetable plastic at present is price. While mass production has lowered costs, plastics made from vegetable resins still cost two to three times as much as those made from petroleum. Industry insiders say that vegetable plastic must be no more than 20% more expensive than petroleum plastic in order to catch on in a wide range of applications. The domestic market for plastic is currently about 15 million tons annually, and plastic made from vegetable resin accounts for only about 10,000 tons. Experts say that a 10% share of the market is a reasonable interim goal.

People in the industry are touting the fact that polylactide is biodegradable in that it can be broken down into carbon dioxide and water following use. In order to bring this point home to consumers, last year such products have been referred to as "plant based," and makers are looking to sell them to environmentally conscious consumers and corporations.

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