Example 2
Into a three-neck flask provided with a condenser and a stirrer, 6.97 g of 1,6-hexanediamine (manufactured by Tokyo Chemical Industry Co., Ltd.) and 53.9 g of N-methylpyrrolidone (manufactured by Kanto Chemical Co., Inc.) were put, and by being stirred at room temperature under a nitrogen flow to obtain a uniform solution. Next, 9.49 g of pyridine (manufactured by Kanto Chemical Co., Inc.) and 7.33 g of 4-dimethylaminopyridine (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the reaction solution, followed by dissolving. Next, 22.03 g of 4,4′-oxybis(benzenesulfonylchloride) (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the flask, followed by stirring at room temperature for 1 hour, then, the temperature was raised to 60° C., and the resulting solution was allowed to react for 10 hours. The reaction solution was added dropwise to a mixed solution of 0.5 L of pure water and 0.5 L of methanol, and as a result, a polymer was precipitated. This was collected by filtration, washed, and dried, whereby 25.5 g of a binder polymer (CP-2) having a weight-average molecular weight of 52,000 was obtained. It was confirmed from the NMR spectrum, the IR spectrum, and GPC (polystyrene conversion) that the obtained product was the target substance.