| 摘要 |
<p>There is disclosed an aqueous suspension containing at least 55% by weight of a mixture of inorganic pigments, which mixture comprises calcium sulphate and at least one other pigment, wherein the or at least one of said at least one other pigment is a pigment which has been treated, prior to its incorporation into the suspension, with a dispersing agent which is (i) a phosphate ester or (ii) a water-soluble salt of polyacrylic acid at least 15% of the carboxylic acid groups of which are esterified. Also disclosed is a paper coating composition which comprises a dispersion of a mixed pigment in an aqueous medium containing an adhesive, wherein the mixed pigment constitutes at least 55% by weight of the composition and wherein the mixed pigment comprises calcium sulphate and at least one other pigment, wherein the or at least one of said at least one other pigment is a pigment which has been treated, prior to its incorporation into the suspension, with a dispersing agent which is (i) a phosphate ester or (ii) a water-soluble salt of polyacrylic acid at least 15% of the carboxylic acid groups of which are esterified.</p> |
