Bisphenol-A. Has an organic compound divided the world as much as this synthetic estrogen? While this chemical compound instills much controversy, anger, fear, and frustration on one side, the other side merely sees it as a protector of food that helps packaging withstand the high temperatures of the sterilization process and, overall, increases products' shelf life.
BPA is a synthetic estrogen used to produce polycarbonate (PC) polymers and epoxy resins. As such, it is present in many hard plastic bottles and containers, metal-based food and beverage cans, in addition to safety equipment, eyeglasses, computer and cell phone casings, and more.
BPA in focus
PlasticsToday and sister publication Packaging Digest have combined resources for a comprehensive report on bisphenol A (BPA), including its history and future, as it relates to packaging.
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Physiologically, BPA is said to mimic the hormone estrogen and has been linked to increased breast cancer risk, obesity, and other health conditions. In addition, about 90% of Americans have traces of BPA in their urine, according to the Endocrine-Related Cancer Journal .
This is partly how BPA become a villain in food packaging, at least in some people's eyes.
"If you stop 10 people on the street, and ask them about BPA, they know right away that it's supposed to be considered bad," Stuart Yaniger, VP of research and product development at PlastiPure, told PlasticsToday. "But if you ask a follow-up question about why it's bad, expect to get a blank look because they don't know why."
Before we get into the current state of BPA and polycarbonate for packaging, along with looking at new technologies to replace PC, let's look back at this chemical's history and how it became the cornerstone of controversy.
History of BPA
It's well documented that BPA was first synthesized by chemists in 1891, however, the first mention of BPA was made in a scientific paper in 1905 by Thomas Zincke of the University of Marburg , Germany.
It wasn't made relevant until the 1950s when the thriving plastic industry underwent a technology revolution with the introduction of new materials, design techniques, and processes, such as injection molding.
Dr. Hermann Schnell of Bayer invented polycarbonate (PC) resin in 1953, just one week before chemist Dr. Daniel Fox of GE made the same discovery while working on developing a new wire insulation material. Both found a gooey substance that hardened in a beaker, and despite their best efforts, they could not break or destroy the material. They were equally impressed by the toughness of the material.
While both companies applied for U.S. patents in 1955, they agreed that the patent holder would grant a license for an appropriate royalty, which allowed both companies to concentrate on developing the polymer.
The main polycarbonate material is produced by the reaction of BPA and phosgene COCl 2. Unlike most plastics, polycarbonate can undergo large deformations without cracking or breaking.