Patent ID: 8536298
Filing Date: 2013-09-17
Classification: C08G

Abstract:
1. A process for preparing polyimide resins comprising: stirring a mixture consisting of a diamine of formula (X): wherein Y is at least one of —O—, —S—, —SO wherein X is —O—, —S—, —SO heating the slurry to a temperature sufficient for the diamine and dianhydride to react and form a reaction mixture wherein the temperature is below the melting point of the dianhydride, below the melting point of the diamine, or below the melting points of the dianhydride and diamine; and reacting the diamine and dianhydride to form a polyimide having sufficient molecular weight to precipitate from the reaction mixture, wherein the diamine, the dianhydride, or both the diamine and the dianhydride are minimally soluble in the solvent and wherein the polyimide has a solubility of less than or equal to 10 weight percent in the solvent under the reaction conditions.