a. Properties The epoxy resin synthesis takes place in various stages, depending on the process. For the preparation of most epoxy resins, di(phydroxyphenyl)- 2-propane (bisphenol A) is reacted with epichlorohydrin. Under basic conditions (NaOH) or in a further reaction with NaOH, a chain extension takes place to an epoxy compound having the general formula (see formula below) . The low to medium-viscosity epoxy resins usually have an average molar mass of 350 to 4,000 g/mole and contain free secondary OH groups in addition to the epoxy groups. Coating materials based on epoxy resins have extremely ...