| 摘要 |
The invention relates to a method for producing aqueous solutions with a low salt content from polymers containing vinylamine units. The method involves treating aqueous solutions of hydrolysed polymers containing N-vinylformamide units with a solvent mixture containing (a) acetone and (b) an alcohol from the group comprising methanol, ethanol, n-propanol, isopropanol and mixtures thereof, in a weight ratio (a):(b) from 1:1 to 10:1, whereby 0.05 to 0.5 wt. part aqueous polymer solution is used to 1 wt. part solvent mixture. The inventive method also involves cooling the obtained mixture to a temperature of 0 DEG C or below and cristallising the neutral salt; separating the neutral salt; and distilling off the solvent. |
