The invention relates to a laminated core, preferably a stator laminated core or a rotor laminated core (2), of an electric machine, in particular an electric fuel pump of a motor vehicle. The laminated core comprises slots (6), each of which has a slot insulation (7), and winding wires of at least one electric winding (10), said wires running in the slots (6). A plastic encapsulation (17) encases the laminated core together with the winding wires which run in the slots (6) at least in some regions. The plastic encapsulation (17) and the slot insulation (7) each consist of a thermoplastic, and the plastic of the slot insulation (7) has a melting point which is equal to, similar to, or lower than the melting point of the plastic of the plastic encapsulation (17) such that the encapsulation process causes the slot insulation (7) to melt, thereby bonding the slot insulation (7) to the plastic encapsulation (17). The invention further relates to a method for producing a laminated core and to an electric machine.