A process for the production of a structured composite pigmentary material comprises mixing an aqueous dispersion of inorganic pigmentary particles and an aqueous dispersion of polyvinyl chloride (PVC) particles. The pigment particles carry a positive surface charge and the PVC particles carry a negative surface charge and the particles are held in association as a result of these charges. The pigment particles and PVC particles are mixed in the presence of a surfactant system which provides both anionic and steric stabilisation. The surfactant system comprises, in one embodiment, a nonionic surfactant having an HLB value greater than 12 and at least 2% by weight of an anionic surfactant with respect to PVC particles, and, in a second embodiment, at least 2% by weight (with respect to PVC) of one of more surfactants providing anionic and steric stabilisation and being ethylene oxide condensation products having an average length of at least 8 oxyethylene units. The product is useful in paints and provides improved opacity and improved gloss.
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