Bisfenol A  (updated 2010)

Bisphenol A (A=acetone) occurs in its pure form as white flakes with a faint phenol-like smell. It is produced in large quantities by a reaction between phenol and acetone.

Bisphenol A is used together with epichlorohydrine for synthesis of bisphenol-A-diglycidylic ether (DGEBA), which is the commonest starting substance for epoxy resin. The resin consists of molecular chains of varying length which are cross-linked in the course of curing to epoxy plastic. Resin can be made fluid or solid by varying ratio between bisphenol A and epichlorohydrine; fluid resins have shorter chains and, consequently, lower than average molecular weight, while resins with longer chains and higher average molecular weight are solid. Epoxy resin based on DGEBA is considered either low- or high-molecular, depending on whether the resin has an average molecular weight below or above about 1,000. Several different types of substances can be used for curing the epoxy resin, but amines are commonest. The curing can be done at room temperature (cold setting) or at higher temperatures, usually 50-150ºC (hot setting).

The low-molecular fluid resins are used in products like adhesive and flooring materials. The more high-molecular solid resins are used in paints and varnishes. 

Thermoplastics like polycarbonates and polysulphones are also produced with bisphenol A as one of the starting substances. Polycarbonates are made of bisphenol A in alkaline water solution into which phosgene is introduced. Their characteristics include high impact strength, hardness, toughness, transparency, resistance to temperatures between about –40ºC and about 145ºC, and resistance to many acids, greases and oils. In addition, they are refractory. The substance is used in everyday objects, both at work and in the home. The polysulphone plastic polyphenylenesulphone (PPSU) can, for example, be made of bisphenol A and 4,4’-dichlorodiphenylsulphone. It can be used in temperatures of up to 150ºC, it tolerates hot water and hot oils and has low combustibility and smoke emission. Transparent aromatic polyesters with good UV resistance and heat resistance up to 150ºC can be made of bisphenol A and phthalic acid. 

Another use for bisphenol A is as an antioxidant in products used in the plastic and rubber industries. Radicals can act in various ways: they can trigger polymerisation or, together with oxygen, form extremely reactive peroxides. Bisphenol A reacts with radicals and forms stable compounds with them. In this way the plastic or rubber is protected from oxidation.

Contact person: Margareta Östman,  Tel +468 519 411 62
Swedish Chemicals Agency Box 2 SE-172 13 Sundbyberg, kemi@kemi.se
Tel +468 519 411 00 Fax +468 735 7698