Patent Number: 6,168,719

Title: Method for the purification of ionic polymers

Abstract: To provide a method for purification of the ionic polymer compound comprising efficiently removing low-molecular impurities, for example, ionic remaining monomers, which are charged identically to the ionic polymer compound from the ionic polymer compound in a shorter period of time. A method for purification of an ionic polymer compound, characterized by removing low-molecular impurities, such as ionic remaining monomers, by the use of an ultrafiltration membrane and/or a reverse osmosis membrane from an aqueous solution containing the ionic polymer compound and low-molecular impurities which are charged identically to the ionic polymer compound, under conditions that a concentration of the ionic polymer compound is from 7 to 20% by weight, and that an amount of charges of the ionic polymer compound in the aqueous solution is 0.30 gram-equivalent/liter or more.

Inventors: Shimokawa; Keishi (Wakayama, JP), Imaki; Takuya (Wakayama, JP), Shida; Jun (Wakayama, JP), Nojiri; Naoki (Wakayama, JP), Hiramatsu; Shinobu (Wakayama, JP)

Assignee: Kao Corporation

International Classification: C08F 6/00 (20060101); B01D 061/00 ()

Expiration Date: 01/02/2018