Patent ID: 9617386
Date: 2017-04-11
CPC Classifications: B05D,C07C,C08G,C08J,C08K,C09D,H01L

Claim:
1. A process of purifying a polymer, comprising: providing an organic solution containing a polyimide or polyamic ester in at least one polar, aprotic polymerization solvent; adding at least one purification solvent to the organic solution to form a diluted organic solution, the at least one purification solvent is less polar than the at least one polymerization solvent and has a lower water solubility than the at least one polymerization solvent at 25° C.; washing the diluted organic solution with water or an aqueous solution, the washing comprises mixing the diluted organic solution with water or an aqueous solution to form a mixture having an organic phase and an aqueous phase, and removing the aqueous phase to obtain a washed polymer-containing organic solution; and removing a portion of the at least one purification solvent in the washed polymer-containing organic solution to obtain a solution containing a purified polyimide or polyamic ester; wherein the process avoids precipitation of the polyimide or polyamic ester.