| 摘要 |
Amphoteric aq. polymer dispersions (D) with 20 - 55 (25 - 45) wt.% solids content and uniform particle size distribution are prepd. by the following two-step radical copolymerisation process. (1) An anionic polymer dispersion (E) with 15 - 45 (20 - 40) wt.% solids content and -3 to -70 (-5 to -30) mV zeta-potential, is prepd. from a monomer mixt. comprising ethylenically unsatd. monomers contg. up to 30 wt.% monomers (A) with anionic character, chosen from ethylenic unsatd. carboxylic acids, sulphonic acids or phosphonic acids, polymerised in presence of enzyme-hydrolysis and / or acid-hydrolysis degraded starches that have a mean mol. wt. of 500 - 2000 (800 - 1500) g / mol. and an intrinsic viscosity < 0.1 d / g. The starch soln. concn. is up to 40 (10 - 35) wt.% and starch / monomer wt. ratio is 20 - 1 : 1 - 20. (2) (E) is polymerised with a monomer mixt. contg. up to 35 (5 - 20) wt.% monomers (B) with cationic (basic) character. The anionic dispersion / added monomer wt. ratio is 10 - 1 : 1 - 10. |
