Process for the production of composite material based on a polymer matrix

A process for the production of a composite material based on a polymer matrix comprising, homogeneously dispersed therein, an organic and/or inorganic filler, the process comprising mixing together aqueous dispersions of the single components, in which the dispersed particles of the dispersions have a surface charge of the same sign and a zeta potential of from 10 to 100 mV (in absolute value) and the ratio (in absolute value) between the zeta potentials of the particles of each dispersion is from 0.2 to 5.