| 摘要 |
The invention relates to a kaolin-based coating agent and filler, as well as to a process for its preparation. According to the invention, small particles of precipitated calcium carbonate with a particle size of essentially 40-60 nm are made to adhere to the anionic surfaces of kaolin. Such a coating agent and filler contains 10-90 wt-% and preferably about 30-70 wt-% of kaolin and about 90-10 wt-% and preferably about 70-30 wt- % of precipitated calcium carbonate. The product is prepared by mixing kaolin and precipitated calcium carbonate in an aqueous medium in order to obtain an aqueous suspension of kaolin and precipitated calcium carbonate. The pH of the aqueous medium is adjusted to a value of 7-10 and especially between about 8 and 9 during the mixing operation in order to make the calcium carbonate adhere to the anionic surfaces of kaolin. The product according to the invention combines the brightness and opacity of precipitated calcium carbonate with the retention and gloss of kaolin.
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