<p>The idea of creating an epoxy-based gradient composition with hardeners of varying activities was proposed to control the exothermic effect during the curing process. Both resin and hardeners in powder form were selected to create a composition appropriate for the production of large-scale products. By modeling the thermal balance in Thermal Simulations software (Netzsch) based on data obtained from Thermokinetics 3 (Netzsch), a comparative analysis of temperature fields in thick-walled polymer samples of non-gradient and gradient compositions was carried out. A single-stage constant heating rate mode was developed to create a controlled gradient of the resin conversion from the inner layers of the part to the outer layers. The polymerization front is created by a certain ratio of hardeners with different reactivities in the layers of the matrix. The use of this method can lead to a reduction in the curing time, the prevention of overheating and a decrease in the residual stresses in the composite part.</p> Graphical abstract <p></p>