More and more uses are being found for next-generation plastics made from such plants as sweet potatoes and sugarcane. Bioplastics are environmentally friendly because, compared with traditional plastics, their production results in the emission of less carbon dioxide, which is thought to cause global warming. They are also biodegradable, meaning that the material returns to its natural state when buried in the ground. Bioplastics are already being used in automobile interiors and in cases for consumer electronics. In 2002 Japan ratified the Kyoto Protocol, which requires countries to reduce their emissions of carbon dioxide and other greenhouse gases, and Japanese corporations will have to play their part in achieving this goal. This means that the use of bioplastics, seen as an effective way of cutting carbon dioxide emissions, is likely to continue to expand.
Toyota Becomes First Automaker to Use Bioplastics
Toyota Motor Corp. became the first automaker in the world to use bioplastics in the manufacture of auto parts, employing them in the cover for the spare tire in the Raum, a new model that went on sale this May. The bioplastic used for the tire cover is made from plants, such as sweet potatoes and sugarcane. Enzymes are used to break starch in the plants down into glucose, which is fermented and made into lactic acid. This lactic acid is polymerized and converted into a plastic called polylactic acid, which can be used in the manufacture of products after being heated and shaped.
When ordinary plastics made from petroleum are burned, they release the carbon dioxide contained in the petroleum into the atmosphere, leading to global warming. Bioplastics, however, are made from plants that grow by absorbing carbon dioxide from the atmosphere, so when they are burned, the level of carbon dioxide in the atmosphere does not change. Because petroleum is not used, emissions of carbon dioxide are cut, and a contribution is made to the fight against global warming.
In addition, bioplastics are biodegradable. If something made of bioplastic is buried in the ground, microorganisms will break it down into carbon dioxide and water. Since this material is environment-friendly, interest in bioplastics is high, and the materials have been the subject of research and development both in Japan and abroad. Bags made of bioplastic can be thrown away and buried with other biodegradable garbage, and there are a growing number of other uses for the materials as well, including artificial fibers, medical products, and construction materials.
Toyota Motor is building a plant to undertake test production of bioplastic at a factory in Japan, with production due to begin in August 2004. The company plans to produce 1,000 tons of bioplastic annually, which will be used not just in car parts but in many other plastic products as well. Toyota also plans to use bioplastics in the construction of the exhibition pavilions at the 2005 World Exposition, Aichi, Japan, so that no construction waste is generated when the pavilions are dismantled at the end of the event. A spokesperson for Toyota Motor's Biotechnology and Afforestation Business Division expresses high hopes for the future of bioplastics, saying, "The inside of a car gets very hot and is exposed to shocks while the vehicle is running. If bioplastics can be used in this tough environment, they can be used in ordinary household products or anywhere else."
Also Used in Electronic Devices
Mitsubishi Plastics has already succeeded in raising the heat-resistance and strength of polylactic acid by combining it with other biodegradable plastics and filler, and the result was used to make the plastic casing of a new version of Sony Corp.'s Walkman released last fall. Mitsubishi Plastics had previously looked at bioplastic as something that would mainly be used in the manufacture of casings and wrappings, but the company now feels confident that this revolutionary material has entered a new phase in its development in which more complex applications will be found.
NEC Corp., meanwhile, is turning its attention to kenaf, a type of fibrous plant native to tropical areas of Africa and Asia that is known to grow more than five meters in just half a year. A mixture of polylactic acid and kenaf fiber that is 20% fiber by weight allows for a plastic that is strong enough and heat resistant enough to be used in electronic goods. The goal is to begin using this new plastic in real products, such as computer cases, within two years.
At present approximately 14 million tons of plastic are produced in Japan annually. Though bioplastics and other environment-friendly plastics account for only about 10,000 tons of this, the market for bioplastics is expected to grow by 400% to ¥20 billion ($181.9 million at ¥110 to the dollar) by 2005.
