An increasing number of Japanese corporations have begun producing biodegradable plastics and other materials less harmful to the environment than conventional ones using plants, reflecting rising environmental consciousness.
TOKYO — An increasing number of Japanese corporations have begun producing biodegradable plastics and other materials less harmful to the environment than conventional ones using plants, reflecting rising environmental consciousness.
Unlike conventional, petroleum-based plastics, biodegradable plastics can be broken down by microorganisms and return to the soil after use, as they dissolve relatively easily underground.
According to the Biodegradable Plastics Society, a Tokyo-based business body made up of more than 200 private companies, it costs 300-350 yen to produce 1 kilogram of plastic from plants, three to four times as much as it costs to produce the same amount of petroleum-resourced plastics.
But demand for biodegradable plastics is rising, an official of the business body said.
In 2000, production of such plastics stood at slightly more than 2,000 tons.
"It will increase to 50,000 tons this year and to 200,000 tons in 2010," the official said.
Ajinomoto Co. has been producing plant-based polybutylene succinate (PBS), a kind of biodegradable plastic, using its fermentation technology.
The company ferments sugar and starch and extracts succinic acid from them. The acid is then combined with 1.4-butanediol to produce PBS, a highly flexible plastic. The 1.4-butanediol is provided by Mitsubishi Chemical Corp.
"Since the raw materials are plants, the plastic can be broken down after use by microorganisms in soil," an Ajinomoto official said.
The price is still relatively high at several yen per shopping bag made of the plastic. But the official is confident the price will fall due to "mass production in the future." Moves to use kenaf, an easy to grow fibrous plant, in building material and boards for home electrical appliances have gained momentum when Matsushita Electric Works Ltd. began producing 100,000 kenaf fiber boards in conjunction with a Malaysian firm in December.
Kenaf matures in 4-5 months and yields about 200,000 tons per hectare, 5-10 times as much as Japanese cedar.
A 4-mm thick kenaf fiber board is said to have more tensile strength than a 9-mm thick piece of conventional plywood. A study is under way to further enhance the strength by mixing kenaf fiber with plant-based plastic.
Toyota Motor Corp. has adopted floor mats made of kenaf fiber for some of its passenger cars.
Japan's leading carmaker has begun producing polylactic acid (PLA), a kind of biodegradable plastic made from starch and sugar extracted from sweet potatoes and other plants.
Domestic annual demand for plastics stands at about 14 million tons.
"Biodegradable plastics will account for about 10 percent of the market in around 2020," said an official of the Biodegradable Plastics Society.
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