Polycarbonate’s link to bisphenol A (BPA) has left it badly bruised in the public eye, but it’s still a darling of design engineers around the world. Growth rates for the rigid transparent engineering thermoplastic in North America are in the 4-5% range, more than double rates for the gross domestic product. Growth rates are closer to 8% in China, which is now the largest global market for PC.
That’s interesting considering the public perception of the material. About 70% of all BPA used globally goes into the production of PC. Contact with water, particularly warm water, releases BPA, which some researchers have identified as an endocrine disrupter. A study conducted in Ohio maintained that exposure in the womb to bisphenol A (BPA) caused behavior and emotional problems in young girls. The study was performed by researchers at the Harvard School of Public Health (HSPH), Cincinnati Children’s Hospital and Medical Center, and Simon Fraser University in Vancouver, British Columbia.
Producers say that polycarbonate is safe, but at the same time have withdrawn it from some applications, notably baby bottles and sippy cups.
One of the interesting intersections of the controversy is the medical market. At the premiere event for medical design and manufacturing in North America, MD&M West, PC producers such as Sabic IP and Bayer MaterialScience proudly show new medical applications while elsewhere resin suppliers hawk PC replacements or tout their materials as “BPA free”.
Is PC safe for medical use? A Who’s Who of chemical companies exhibiting at MD&M imply that it is not. Public health research has focused on the better-known bottle and packaging applications. The approach used by polycarbonate producers is to poke holes in research after results are announced rather than to proactively fund a major third-party study to demonstrate the safety of BPA. Emphasis in the industry seems to be on public relations and lobbying, not health research. A Web page shows their approach.
Producers have mostly taken a head-in-the-sand tack to the BPA controversy, a strategy that led to an extremely embarrassing moment at last year’s Annual Technical Conference of the Society of Plastics Engineers.
That’s too bad because it’s a great material: transparent, tough, good thermal properties and good electrical properties.
And the most important applications for polycarbonate seem to avoid potential conflict. The biggest market now is electronic components, partly because of its safety features. It’s a good electrical insulator and has heat resistant and flame retardant properties. Its durability is why it’s widely used as a housing alloy in many electronics products. Its use in automotive is rising because it reduces weight. A major potential use of PC is as a glazing material to replace glass in cars. It would be an important way to meet new fuel mileage guidelines.
Polycarbonate was invented by Dan Fox at GE in 1953. When GE decided that plastics were no longer attractive as a business, polycarbonate was one of the crown jewels that made the made the business attractive to Saudi Arabian Basic Industries Corp. (SABIC). Sabic is part owner of a new plant in Saudi Arabia that is the world’s largest.
And earlier this week, Prince Saud, chairman of SABIC, and Fu Chengyu, chairman of the Sinopec Group, signed a deal to jointly develop massive polycarbonate capacity in China, currently the biggest importer of the material in the world. A plant with a capacity of 260,000 metric tons is planned for Tianjin, China. According to one published estimate, the Asian demand for polycarbonate in 2009 was 930,000 tons.
The problem polycarbonate faces is more attitudinal than technical.
Its major entry into the market as an automotive material in Europe a very long time ago illustrates the industry’s approach to the market—and its shortcomings. An aggressive marketer sold PC into the application without conducting adequate testing on its fitness for purpose. Contact with gas ruined parts in the field. The resin producer launched an all-out effort to solve the problem and invented a now widely used alloy that provides the crash-resistance of PC while also resisting chemical attack.