Thursday, April 24, 2008

PC World - Could Your CD Contain Corn?

Could Your CD Contain Corn? Sanyo uses vegetables to build an
environmentally friendly disc. Martyn Williams, IDG News Service
Monday, October 20, 2003 01:00 AM PDT
Sanyo Electric has developed an optical disc based on a polymer
derived from corn which, the company says, is as sturdy as current
plastic discs but will biodegrade when disposed of.

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 CDs, such as music CDs,
VideoCDs, or CD-ROMs, said Ryan Watson, a Tokyo-based spokesperson for
Sanyo, which is headquartered in Osaka.


The discs have been designed to tackle a problem common to many
plastics upon disposal: If burned, toxic gases can be released into
the atmosphere causing health and global warming concerns; but if
buried, they don't break down, causing a potential problem for future
generations. The MildDisc will degrade after a period of about 50 to
100 years and break down into water and carbon dioxide, Watson said.
This time span means users don't have to worry about losing
information during the lifetime of the discs, he said.

Out on the Farm
The production process begins when Cargill Dow in Nebraska converts
corn into a polylactic acid. This is done by milling the corn to
separate out the starch and then processing the starch to get
unrefined dextrose. Using a fermentation process similar to that of
beer production, the dextrose is converted into lactic acid, according
to the company's Web site.

The acid is 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, Watson
said.

Sanyo estimates that around 85 corn kernels, each weighing an average
of 0.5 grams, are needed to produce enough polymer for a single 4.7-
inch optical disc, so an average ear of corn can produce around ten
discs. The International Recording Media Association estimates world
demand for CDs at around 9 billion annually, and the U.S. 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 percent of the world's corn production.

Coming Soon?
Initially the company will focus on discs for prerecorded
applications, although it is considering recordable and rewritable
versions of the MildDisc. DVDs based on the same technology are also a
future possibility, according to Watson.

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

Cargill Dow is using the same initial process and its own refining
process to produce its NatureWorks PLA polymer film. Several companies
are using the film to produce a range of goods including cartons,
candy wrappers, kitchen utensils, and acrylic sheets and fabrics.

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