Application of silica-based pigments in water-borne acrylic paints and in solvent-borne acrylic paints

The amorphic silica, Syloid 244 was modified using N-2-(aminoethyl)-3-aminopropyltrimethoxysilane. Pigments based on the silica carrier were obtained by coupling the organic dye, C.I. Reactive Blue 19 to the modified surface of the silica. The adsorption process was conducted in an aqueous suspension of the silica, supplemented with the dye. An extent of modification was evaluated using infrared spectroscopy and nuclear magnetic resonance spectroscopy. Structural and microscopic properties of the product were examined as were the zeta potential and the particle size distribution. The specific surface area was estimated using a BET approach. The efficiency of the adsorption process and the effects of the amount of dye and type of dye, on the final product, were determined. Moreover, the stability of the chemical bonds that were formed between the dye and the carrier was examined in elution tests. The pigments obtained were tested in water soluble binders and in organic solvent-solubilised acrylic paints.