Improvement of Paper Properties Using Starch-Modified Precipiated Calcium Carbonate Filler, 2005 Papermakers Conference

Commercial filler, precipitated calcium carbonates (PCC), were modified with corn and potato raw starches. These modified fillers were used to improve the sheet strength in high filler content papers. The filler treatment was performed by mixing the PCC filler with uncooked starch at high solid content (>45%), and then cooking the mixture. It was found that the water content in the cooking mixture plays an important role in the filler modification. Experiments indicate that the PCC could be coated by starch gel by the method described in this paper. No significant dissolution of the PCC coated starch gel was found during the papermaking process. Handsheet physical properties including tensile, tearing, and folding could be improved dramatically with starch-coated PCC compared to the conventional method of adding cooked starch. These improvements were consistent when different types of starch were evaluated. Negligible differences in physical and optical paper properties were observed among the starch-modified PCC fillers added handsheets using different types of starches.