PURPOSE: To obtain an aggregated calcium carbonate, having a low white paper whiteness in coating paper therewith, excellent in printability, etc., such as ink absorptivity, capable of improving the yield when internally added in paper and excellent in optical characteristics of whiteness and opacity of paper.
CONSTITUTION: This aggregated calcium carbonate is formed by aggregating calcium carbonate particles having 0.6-0.8μm major axis, 0.21-0.30μm minor axis and <3 aspect ratio and has 3.0-10μm average particle diameter or 1.0-10μm average particle diameter with the lower limit of the average particle diameter reduced to 1.0μm. The calcium carbonate having 3.0-10μm average particle diameter is used as a papermaking coating pigment and the calcium carbonate having 1.0-10μm average particle diameter is used as a papermaking internal pigment. The aggregated calcium carbonate has strong cohesiveness and is hardly disintegrated without changing particles even in filtering, drying and classifying steps in a product-forming process and steps where a high shearing force is applied such as dispersing, coating and sheet-forming steps in a papermaking process.
SUZUKI AKIRA
YAMASHITA KAZUO
SHIMONO KAZUHISA
HORIUCHI HIDEKI
| JPS638048A | 1988-01-13 | |||
| JPS6418911A | 1989-01-23 |