Role of particle size and preflocculation of talc in improvement of paper properties

Mineral fillers are added during papermaking to improve the optical and printing properties of paper and decrease energy costs. Filler loading using conventional approaches has some disadvantages, such as reduction in paper strength. The finer filler, the more the strength loss. Several methods and materials have been reported to overcome or alleviate the same, but with higher costs. Our approach provides an economically viable solution to the problem, using conventional papermaking materials. Talc filler of different particle sizes, preflocculated using different doses of cooked amphoteric starch, were used for papermaking. Relatively higher filler retention, paper strength, and hydrophobicity of paper were obtained with preflocculated talc compared to native talc. The optical properties of paper were unchanged on the loading of similar talc after preflocculation. The preflocculated talc of finer particle size provided higher opacity at similar ash, as well as paper strength, than the native talc of coarser size.