| 摘要 |
PURPOSE: To obtain a binder which comprises a highly dispersible and high surface area precipitated calcium carbonate and a cationic starch, by which paper excellent in strength and opacity is obtained and the retention level is improved. CONSTITUTION: The precipitated calcium carbonate is obtained by introducing carbon dioxide into calcium hydroxide aqueous slurry prepared by adding preferably (2-hydroxyethylimino)bis(methylene)bis-phosphonic acid and aluminum sulfate-18 hydrate salt until the precipitation of calcium carbonate is completed. The resultant calcium carbonate is heated, heatedly aged and treated with sodium triphosphate, etc., to obtain the highly dispersible and high surface area precipitated calcium carbonate. This calcium carbonate is blended with the cationic starch (preferably cationic potato starch having 0.30-0.40 substitution degree) in the weight ratio of 1:4-1:10 to obtain the binder for papermaking. |
