| 摘要 |
PROBLEM TO BE SOLVED: To provide engineered calcium carbonate having an average particle diameter of 0.1-0.5μm and a sharp particle size distribution, to provide a method for producing such engineered calcium carbonate, to provide a coating material for paper making containing such engineered calcium carbonate, and to provide a coated paper sheet obtained by coating with such engineered calcium carbonate. SOLUTION: The method for producing calcium carbonate having an average particle diameter (d<SB>50</SB>) of 0.1-0.5μm measured with an X-ray transmission particle size distribution measuring instrument, a BET specific surface area in a range of 10-30 m<SP>2</SP>/g and a degree of sharpness (d<SB>30</SB>/d<SB>70</SB>×100) of≥50 measured with the X-ray transmission particle size distribution measuring instrument includes wet-milling light calcium carbonate in spindle-shaped calcite crystals in a solid concentration of≤50 wt.%. COPYRIGHT: (C)2010,JPO&INPIT |
