Preparation and properties of a flexible curing agent

Low molecular weight epoxy resin, bisphenol A and flexible chain carboxylic acid were used to synthesize a flexible curing agent used in powder coating by two-step method. The structure was characterized by Fourier transforms infrared spectrometer (FT-IR) and gel permeation chromatography (GPC). The mechanical properties and gel time of the powder coating were tested. The curing kinetics was studied through differential calorimetric analysis (DSC). As a result, modified reagent was successfully grafted onto the curing agent. The hydroxyl value is 0.55 mol/100g~0.65 mol/100g, softening point is 90°C~98°C; gel time is 21 s at 180°C, impact toughness is 50kg·cm, and adhesive force level is 0 degree. The apparent activation energy of the curing system is 76.83 kJ/mol and the reaction order is 0.92.