| 摘要 |
The viscosity increase of aqueous calcium carbonate pigment suspensions having high concentrations of dry substance is prevented by adding as a compatibility, dispersing, and/or grinding agent to an aqueous calcium carbonate suspension a copolymer of the formula: <IMAGE> wherein R1 is H or methyl, R2 and R3 is H, C1-4 alkyl or a carboxylic acid group, R4 is H or C1-4 alkyl, R5 is a bridging group, R6 is H, a cation, an amino group, C1-3 alkyl, C1-4 ester or substituted amide and R7 to R9 each is hydrogen, a carboxylic acid containing group; K has a value between 30 and 65% by weight relative to the total weight; L has a value between 20 and 60% by weight relative to the total weight; M has a value between 10 and 45% by weight relative to the total weight; and the sum of L and M is equal to at least 35% by weight relative to the total weight, thereby preventing the shock effect when a concentrated alkaline electrolyte is added to the suspension.
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