Described is a process for preparing a powder coating material, in which a mixture comprising binders, pigments and also, where appropriate, fillers, additives and cross linkers is extruded and then ground. The pigment fraction of this mixture at least in part comprises surface-modified effect pigment that has been coated with a low molecular mass polyethylene or polypropylene. Also, described is a powder coating material prepared by this process and the use of effect pigments coated with low molecular mass polyethylene or polypropylene to prepare powder coating materials.