Development of Sedimentation Resistant Water-Acrylic Titanium Dioxide Dispersions

Abstract

According to the results of the research, the effect of stabilization of dispersions of titanium dioxide in water-acrylic compositions was established. It was proved that in aqueous-acrylic suspensions at all variations of film-forming agent (from 0 to 5 g/dm3), the maximum of stabilizing activity of the surfactants under study is achieved at CSAS=0.25 g/dm3. The minimum deposition rate of titanium dioxide dispersions at a dosing of 0.25 g/dm3 of sodium polyacrylate was at the level of 0.097 10-3 g/s at any content of film-forming agent (Cff=0.5÷5 g/dm3) in suspensions. At the introduction of the same concentration (CSAS=0.25 g/dm3) of the polyether siloxane copolymer, a decrease in sedimentation rate to 0.053 10-3 g/s in suspensions with a limited acryl content (C≤1 g/dm3) was recorded. At an increase in the concentration of a film-forming agent (C>1 g/dm3) in suspensions, sedimentation stability decreased, which is proved by an increase in the sedimentation rate of TiO2 to 0.110∙10-3 g/s at Cff=5.0 g/dm3. It was found that in aqueous-acrylic suspensions with the film-forming content from 0.5 to 1 g/dm3, the minimum average diameter was 2.64÷3.1 μm CSAS=0.25 g/dm3. Further concentration of acryl (Cff=4÷5 g/dm3) at the same dosage of polyether siloxane copolymer was accompanied by an increase in the average particle size up to 4.30÷4.61 μm. The maximum of wedging activity of sodium polyacrylate (CSAS=0.25 g/dm3) corresponds to the same minimum of the average diameter (2–3 μm).