From Thomas Regional Industrial Market Trends
Polycarbonate (PC) is celebrating the 50th year since its development,
and retirement - or even slowing down - is not in the picture. In fact,
the material is in its prime, regarded by many as the classic engineering
thermoplastic because it exhibits the best of that polymer class's properties,
applications potential and versatility. In fact, polycarbonate (PC)
might be as close as possible to being the ideal engineering resin because
its diverse and adaptable properties allow it to satisfy many high-performance
demands.
"It's the versatility of polycarbonate that's enabled markets
for it to grow," notes Richard C. Crosby, global product manager
for the Lexan resin business at GE Plastics in Massachusetts, USA. Polycarbonate
is versatile enough to thwart bullets when laminated or hold digital
images, he notes. While many resins may also be seasoned veterans -
in existence for 50 years or more - few have prospects as bright as
that of PC. The resin has already excelled in varied areas, and in the
future, it's expected to make major headway in new and more advanced
applications. "The product cycle of polycarbonate is far from mature,"
observes Sander Van Veen, global product manager for Emerge polycarbonate
at Dow Plastics in Switzerland.
Suppliers point to its tailorability as a chief strength, a trait that
allows for alloying and blending or polymer modification. "Like
an artist, we have a broad palette with which we can create," says
Roger Rumer, director of polycarbonate product management for the Americas
at ICMA member Bayer Polymers, Pennsylvania, USA. For example, Mitsubishi
Engineering-Plastics Corp., New York, USA is developing a polycarbonate
and polypropylene blend for interior automotive parts. Such a combination
would unite the heat resistance and impact strength of polycarbonate
with the chemical resistance and affordability of polypropylene.
Brief History
Polycarbonate was developed in 1953 in the U.S. and Germany. In Pittsfield,
Massachusetts. A GE scientist, Daniel W. Fox inadvertently discovered
PC while working on a wire-coating material. According to accounts,
he left for home and came back the following day to find that the coating
had set into a hard, transparent material. That marked the beginning
of Lexan polycarbonate. Meanwhile, in Germany, Hermann Schnell discovered
polycarbonate at Bayer's main lab in Uerdingen, Germany at a time when
the company was searching for ways to advance its technology. Schnell's
find marked the start of the company's Makrolon polycarbonate. Both
companies began to commercially produce PC in 1958. According to Rumer
from Bayer, it's the process used that mostly accounts for the differences
between Makrolon and Lexan polycarbonate-as well as other grades.
Future Watch
Polycarbonate's strong points -transparency, impact resistance and thermal
stability - are paving the way for highly tailored new grades. For example,
GE has created a copolymer grade of Lexan for optical media that disintegrates
after 24-36 hours of contact with oxygen. According to Crosby, the material
will give consumers a sneak peek into new movies or software on optical
discs, which would start to degrade as soon as they are unwrapped. Consumers
can then decide if they would like to purchase a permanent copy.
Meanwhile, Bayer is unveiling a new grade for applications with extremely
high temperature requirements. Makrolon DP1-1848 continues to exhibit
superb low-temperature impact strength after recurring exposure to elevated
temperatures. This is unique, according to Rumer, because PC typically
weakens after heat aging. The new grade is suitable for both automotive
and aerospace applications.
GE and Bayer have partnered on a venture called Exatec, which is focused
on polycarbonate automotive glazing. The joint venture is already producing
windows at a plant near Detroit, MI, USA, says Gregory Adams, general
manager for global marketing at GE. And so far, Rumer reveals, polycarbonate
has been designated in side windows, rear windows and sunroofs on some
cars. The ultimate application would be windshields, where Rumer says
the material could remove 10-20 lbs. of weight.
But first, polycarbonate must surmount limitations in scratch resistance
and UV stability. Van Veen from Dow says it can accomplish this with
coatings. The company has developed a hardcoating technology for polycarbonate,
he notes. But Yasuo Teraoka, vice president of Mitsubishi Engineering-Plastics
Corp., is a little more guarded, noting that it will take a "few
more years" before automotive glazing gains widespread commercial
acceptance.
While its prospects in automotive glazing may be mixed, polycarbonate
can bank on optical discs and in-mold decoration to become two huge
markets. Optical discs are making tremendous gains in capacity, and
this increase will place more demands on the flow, moldability and birefringence
of polycarbonate.
Meanwhile, in-mold decoration using polycarbonate film is expected
to be a robust market, as PC use in applications such as cell phones
and automotive exterior panels will likely increase, suppliers say.
In fact, in automotive exteriors, PC film could eliminate both the hefty
cost of paint lines (up to $500 million for one line) and their harmful
emissions.
In short, polycarbonate will continue to be in high demand, as applications
become more exacting and product design moves forward. Its 50th anniversary
marks both a notable past and a promising future.