Substituting titanium dioxide by calcium carbonate in paint mixtures
Titanium dioxide (TiO2) due to its high refractive index, is widely used in paint industry as a white pigment.
In order to reduce this high cost of TiO2, a part of TiO2 is generally substituted by some other industrial mineral fillers such as calcite and calcined kaolin; however, this substitution affects the quality of paints in terms of stability, coverage (opacity), brightness (gloss), scrub resistance (film toughness), etc.
Obtaining higher film toughness is possible with PCC
In a paper, precipitated calcium carbonate (PCC) was substituted for TiO2 in paint mixture at three different pigment volume concentrations (PVC). It was observed that substitution of TiO2 by PCC depends on PVC value at which there is an optimum PCC amount. The quality of paints produced by PCC along with its rheological properties was evaluated based on standard features in both wet and dry paints such as viscosity, density, opacity and gloss values. Addition of PCC increases the opacity to a certain point.
Similarly, scrub resistance and viscosity increases with the addition of PCC at all PVCs, however, viscosity is not as much critical for the paint production. On the other hand, there is no any systematic effect of PCC on gloss value of the paint. This study overall demonstrates that PCC can be successfully used to substitute TiO2 only with a careful adjustment of PVC and other extenders used in the paint formulation.
You can find further and extensive information about Titanium Dioxide can also be found in Jochen Winklers textbook about Production, Properties and Effective Usage of TiO2. Winkler is one of the best known specialists on this topic.
More and extensive information about fillers can also be found in an established textbook. In the second and revised edition of his specialist book, author Detlef Gysau writes about production technology, analytics applications.
The study is published in: Progress in Organic Coatings, Volume 83, June 2015, Pages 64–70
