Patent ID: 7985789

Claim:
An aqueous nanocomposite polymer dispersion obtained by emulsion polymerization of at least one monomer composition in the presence of at least one aqueous dispersion of silica nanoparticles, characterized in that: said monomer composition is added, in at least one stage, to the reactor already comprising the aqueous dispersion of silica nanoparticles which is devoid of any cationic organic compound from monomers or dispersants or initiators which can function as stabilizers of said silica nanoparticles, said initial aqueous dispersion of silica nanoparticles: is based on anionic nanoparticles of silica modified with aluminum and devoid of any coupling agent, is stable in a pH range extending from 2 to 10, which stability is expressed in terms of absence of aggregates and/or agglomerates and/or sedimentation, said emulsion polymerization is carried out in the presence of at least one organic initiator system free from any ionic group and in the absence of cationic monomers, initiators or dispersants.