| 摘要 |
Provided are a multi-stage polymer comprising a first stage and second stage polymer as a grinding additive and the preparation process thereof. The first stage polymer is prepared from a mixture of : a) 0.1-50 wt% of a nonionic macro-monomer; b) 30-70 wt% an α, &bgr; - ethylenically&bgr; unsaturated carboxylic acid monomer; and c) 30-70 wt% α, &bgr; - ethylenically unsaturated nonionic monomer. The polymerization units of the second stage polymer comprise: e) 10-70 wt% of a α, &bgr; - ethylenically unsaturated carboxylic acid monomer; and f) 30-90 wt% nonionic α, &bgr; - ethylenically unsaturated monomer. |
