What is BPA?
BPA means bisphenol A. It’s an industrial chemical used to make certain plastics since the 1950s.
BPA is found in polycarbonate plastics used in containers to store food and beverages (water bottles, baby bottles, baby pacifiers) and epoxy resins used to coat the inside of metal products (food cans, bottle tops and water supply lines).
BPA is used to improve mechanical, thermal and transparency properties of polycarbonates due to its high molecular rigidity and distorted molecular structure.
One of the problems is that BPA is soluble. The bond between plastic and BPA breaks when it is heated or when it comes into contact with liquids and solvents.
BPA is Toxic and Carcinogenic
BPA can migrate into food and beverages stored in materials containing the substance.
BPA is a xenoestrogen, exhibiting estrogen-mimicking, hormone-like properties.
It has been linked to causing reproductive, immunity, neurological, cardiovascular and metabolic problems.
BPA Exposure at an early-life stage may be extremely toxic and may increase susceptibility to mammary and prostate cancers.
BPA is found in blood, urine and sweat of people who have been contaminated.
There are no established medical interventions to eliminate BPA from the human body.
A product is “BPA free” if no Bisphenol A was used to produce it.
There are two options to achieve “BPA-free” products: a ban or a voluntary removal.
BPA is banned in many countries, but it’s not a full ban. BPA is usually banned from baby applications but still authorised in food containers and packaging.
The EFSA (EU) and FDA (US) still consider BPA as safe at the current levels occurring in foods.
Once in a while EFSA (European Food Safety Authority) does a re-assessment of BPA.
There’s clearly an evolution towards reduction and eventual elimination of BPA. The acceptable daily intake points in that direction.
Acceptable Daily Intake
The unit of ADI or tolerable Daily Intake (TDI) for a chemical substance is
- mg/kg bw/day = milligram per kg body weight per day
- µg/kg bw/day = microgram per kg body weight per day
1 microgram = 0.001 mg
In 2006, EFSA set the TDI for BPA at of 50 µg/kg bw/day = 0.05 mg/kg bw/day
The current EFSA TDI set in 2014 is 4 µg/kg bw/day = 0.004 mg/kg bw/day
EFSA may classify BPA as safe for adults, but people may remain sceptical when considering life long exposure and consumption to BPA.
Bio-based and Biodegradable Alternatives
There are alternatives to BPA.
Isosorbide is a bio-based and biodegradable alternative to BPA.
The most popular isosorbide is marketed under the trade name POLYSORB® by the French company Roquette.
The average percentage of POLYSORB® biodegradability after 28 days of incubation, was 93%
Isosorbide improves the mechanical properties of the incorporated polymer.
It will also provide good optical and UV resistance functionalities due to its unique molecular structure thanks to removing aromatic parts.
Isosorbide also has a better carbon footprint than BPA.
Please contact Roquette for any further information on POLYSORB® isosorbide’
Let’s look at a concrete example.
One of the most used applications containing BPA are water dispenser bottles. They are usually made from polycarbonates containing BPA.
We could manufacture those water dispensers with PET (polyethylene terephthalate) upgraded with isosorbide; it would be referred to as PEIT (polyethylene-co-isosorbide terephthalate).
Why would we do this?
Isosorbide is plant-based and has a lower carbon footprint than BPA.
PET bottles are the most recycled plastic application in the world. PEIT is completely compatible and miscible with regular PET. PEIT bottles are fully recyclable with PET bottles and would fall under the resin identification code 1 (RIC 1), the code reserved for PET. This means that after use the PEIT bottles could be disposed of and reused/recycled via existing PET- handling channels.
Polycarbonate doesn’t have its own Resin Identification Code, and falls under Code “7” (Other plastics).
An important limitation of PET (polyethylene terephthalate) is that it does not have high thermal resistance. Incorporating high purity isosorbide increases the Tg of the copolyester, directly addressing this issue. The resulting polymer, PEIT has a substantially improved thermal profile.