| 摘要 |
1317563 Clay/calcium carbonate pigment ENGLISH CLAYS LOVERING POCHIN & CO Ltd 4 Sept 1970 [9 Sept 1969] 44561/69 Heading C4A [Also in Division C3] A mixed clay/calcium carbonate pigment is obtained by mixing a deflocculated aqueous suspension of CaCO 3 containing a dispersant with an aqueous clay suspension having a pH up to 6À5 to flocculate the clay, and dewatering the admixture to obtain a pigment cake. The CaCO 3 may be chalk whiting, ground marble, calcite or precipitated CaCO 3 and the clay kaolin, halloysite, dickite or nacrite. The dispersant may be Na, K or NH 4 poly-acrylate or -methacrylate, a lignosulphonate, or a Na salt of a sulphonated naphthalene/formaldehyde condensate. The mixed pigment preferably contains not more than 75% by wt. CaCO 3 . |
