A process for the preparation of composite filler particles, comprising: (a) coating a particulate filler having a median particle size (D50) of from 1 to 1200 nm; (b) agglomerating the coated particulate filler, for providing a granulation of the coated particulate filler wherein the granulation contains the coated particulate filler particles whereby the at least one coating layer may be crosslinked by crosslinking groups obtained by reacting the reactive groups and optionally a further crosslinking agent.