What problems do adduct hardeners pose with regard to REACH legislation? To produce epoxy resin hardeners with specific properties, the amines used need to form adducts. This involves adding compounds containing epoxy groups such as bisphenol A diglycidyl ether to one or more amines. Using the current technique in accordance with REACH, this produces new non-polymeric substances that need to be registered accordingly. To keep the registration work and the associated costs in check, the industry and the ECHA agreed to no longer use mixed adducts but to work with in situ adducts (model substances). These are then registered via ...