| 摘要 |
<p>A method for preparing a paper coating composition comprising an aqueous dispersion of fine particle size calcium carbonate, containing 10 to 32% solids, which comprises mixing dry poly(vinyl alcohol) particles in an aqueous dispersion of calcium carbonate particles, the calcium carbonate particles having a mean surface area of at least 60 m 2 /g, until the poly(vinyl alcohol) particles dissolve, to form a dispersion of calcium carbonate particles in an aqueous poly(vinyl alcohol) solution, the dispersion of calcium carbonate particles in the aqueous poly(vinyl alcohol) solution comprising 0.1 to 50 parts poly(vinyl alcohol) per 100 parts calcium carbonate, the poly(vinyl alcohol) having a degree of polymerization of 150 to 300 and being 87 to 89 mole% hydrolyzed, and the poly(vinyl alcohol) particles having an average particle size of 180 µm or less, and optionally mixing other coating additives with the dispersion of calcium carbonate in the aqueous solution of poly(vinyl alcohol), wherein said added poly(vinyl alcohol) particles cooperate with the fine particle size calcium carbonate to lower the Brookfield Viscosity of said aqueous dispersion of calcium carbonate particles.</p> |
