Sanyo grows 'greener' optical disc

Sanyo has developed a biodegradeable optical disc based on a polymer derived from corn which, the company says, is as sturdy as a...

Sanyo has developed a biodegradeable optical disc based on a polymer derived from corn which, the company says, is as sturdy as a plastic disc.

The company, which is claiming a world first for the technology, will begin selling its MildDisc in December. It is initially targeting volume customers producing prerecorded compact discs, such as music CDs, video CDs or CD-Roms, said Sanyo spokesman Ryan Watson.

Sanyo is considering recordable and rewritable versions of the MildDisc, and DVDs based on the same technology are also a future possibility.

The discs have been designed to tackle a problem common to many plastics upon disposal. If they are burned, toxic gases are released into the atmosphere, and if buried, they do not break down, causing a potential problem for future generations.

The MildDisc will degrade after a period of about 50 years to 100 years and break down into water and carbon dioxide.This time span means users need not worry about losing information during the lifetime of the discs.

The corn is milled to separate out the starch and the starch is then processed to create unrefined dextrose. Using a fermentation process similar to that of beer production, the dextrose is converted into lactic acid.

The acid is then converted into a polymer to form the base of the optical disc by Sanyo in a process the company developed with Japan's Mitsui Chemicals, for which the companies have applied for patents.

Sanyo estimates that around 85 corn kernels, each weighing an average of 0.5 grams, are needed to produce enough polymer for a single 12-centimetre optical disc, so an average ear of corn can produce around 10 discs.

The International Recording Media Association estimates world demand for CDs at around nine billion annually, and the US Department of Agriculture estimates world corn production at about 600 million tons, so producing enough polymer to satisfy the demand for discs would require less than 0.1% of the world's corn production.

When sales begin at the end of this year, the disc blanks will sell in bulk for roughly three times the price of plastic discs. However, Sanyo estimated it will be able to reduce this premium to around 1.2 times as production increases and volume shipments begin.

Martyn Williams writes for IDG News Service

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