USES
Bisphenol A is used primarily to make plastics, and products using bisphenol A-based plastics have been in commercial use since 1957. At least 3.6 million tonnes (8 billion pounds) of BPA are used by manufacturers yearly. It is a key monomer in production of epoxy resins and in the most common form of polycarbonate plastic. Bisphenol A and phosgene react to give polycarbonate under biphasic conditions; the hydrochloric acid is scavenged with aqueous base.
Diphenyl carbonate may be used in place of phosgene. Phenol is eliminated instead of hydrochloric acid. This transesterification process avoids the toxicity and handling of phosgene.
Polycarbonate plastic, which is clear and nearly shatter-proof, is used to make a variety of common products including baby and water bottles, sports equipment, medical and dental devices, dental fillingssealants, CDs and DVDs, household electronics, eyeglass lenses foundry castings, and the lining of water pipes.
BPA is also used in the synthesis of polysulfones and polyether ketones, as an antioxidantin some plasticizers, and as a polymerization inhibitor in PVC. Epoxy resins containing bisphenol A are used as coatings on the inside of almost all food and beverage cans; however, due to BPA health concerns, in Japan epoxy coating was mostly replaced by PET film. Bisphenol A is also a precursor to the flame retardant tetrabromobisphenol A, and was used as a fungicide.
Bisphenol A is a preferred color developer in carbonless copy paper and thermal point of sale receipt paper. When used in thermal paper, BPA is present as "free" (i.e., discrete, non-polymerized) BPA, which is likely to be more available for exposure than BPA polymerized into a resin or plastic. Upon handling, BPA in thermal paper can be transferred to skin, and there is some concern that residues on hands could be ingested through incidental hand-to-mouth contact. Furthermore, some studies suggest that dermal absorption may contribute some small fraction to the overall human exposure. European data indicate that the use of BPA in paper may also contribute to the presence of BPA in the stream of recycled paper and in landfills. Although there are no estimates for the amount of BPA used in thermal paper in the United States, in Western Europe, the volume of BPA reported to be used in thermal paper in 2005/2006 was 1,890 tonnes per year, while total production was estimated at 1,150,000 tonnes per year. (Figures taken from 2012 EPA draft paper). Epoxy resin may or may not contain BPA, and is employed to bind gutta perchain some root canal procedures.
Identification in plastics
Plastic packaging is split into seven broad classes for recycling purposes by a Plastic identification code. As of 2014 there are no BPA labeling requirements for plastics in the US. "In general, plastics that are marked with Resin Identification Codes 1, 2, 3, 4, 5, and 6 are very unlikely to contain BPA. Some, but not all, plastics that are marked with the Resin Identification Code 7 may be made with BPA." Type 7 is the catch-all "other" class, and some type 7 plastics, such as polycarbonate (sometimes identified with the letters "PC" near the recycling symbol) and epoxy resins, are made from bisphenol A monomer. Type 3 (PVC) may contain bisphenol A as an antioxidant in "flexible PVC" softened by plasticizers,[8] but not rigid PVC such as pipe, windows, and siding.
Diphenyl carbonate may be used in place of phosgene. Phenol is eliminated instead of hydrochloric acid. This transesterification process avoids the toxicity and handling of phosgene.
Polycarbonate plastic, which is clear and nearly shatter-proof, is used to make a variety of common products including baby and water bottles, sports equipment, medical and dental devices, dental fillingssealants, CDs and DVDs, household electronics, eyeglass lenses foundry castings, and the lining of water pipes.
BPA is also used in the synthesis of polysulfones and polyether ketones, as an antioxidantin some plasticizers, and as a polymerization inhibitor in PVC. Epoxy resins containing bisphenol A are used as coatings on the inside of almost all food and beverage cans; however, due to BPA health concerns, in Japan epoxy coating was mostly replaced by PET film. Bisphenol A is also a precursor to the flame retardant tetrabromobisphenol A, and was used as a fungicide.
Bisphenol A is a preferred color developer in carbonless copy paper and thermal point of sale receipt paper. When used in thermal paper, BPA is present as "free" (i.e., discrete, non-polymerized) BPA, which is likely to be more available for exposure than BPA polymerized into a resin or plastic. Upon handling, BPA in thermal paper can be transferred to skin, and there is some concern that residues on hands could be ingested through incidental hand-to-mouth contact. Furthermore, some studies suggest that dermal absorption may contribute some small fraction to the overall human exposure. European data indicate that the use of BPA in paper may also contribute to the presence of BPA in the stream of recycled paper and in landfills. Although there are no estimates for the amount of BPA used in thermal paper in the United States, in Western Europe, the volume of BPA reported to be used in thermal paper in 2005/2006 was 1,890 tonnes per year, while total production was estimated at 1,150,000 tonnes per year. (Figures taken from 2012 EPA draft paper). Epoxy resin may or may not contain BPA, and is employed to bind gutta perchain some root canal procedures.
Identification in plastics
Plastic packaging is split into seven broad classes for recycling purposes by a Plastic identification code. As of 2014 there are no BPA labeling requirements for plastics in the US. "In general, plastics that are marked with Resin Identification Codes 1, 2, 3, 4, 5, and 6 are very unlikely to contain BPA. Some, but not all, plastics that are marked with the Resin Identification Code 7 may be made with BPA." Type 7 is the catch-all "other" class, and some type 7 plastics, such as polycarbonate (sometimes identified with the letters "PC" near the recycling symbol) and epoxy resins, are made from bisphenol A monomer. Type 3 (PVC) may contain bisphenol A as an antioxidant in "flexible PVC" softened by plasticizers,[8] but not rigid PVC such as pipe, windows, and siding.