| 摘要 |
<p>The present invention is to provide a method for collecting diaminodiphenyl ether (ODA) with an excellent whiteness index. More specifically, the method for collecting ODA comprises a first hydrolysis step, a first filtering step, a first separation step, a second hydrolysis step, a second filtering step, a second separation step and a drying step. In the first hydrolysis step, polyimide is hydrolyzed by reacting 480-960 parts by weight of alkali, 3000-4000 parts by weight of water and 10 parts by weight of reducing agents, with respect to 1000 parts by weight of polyimide, at temperatures of 90-99°C under nitrogen atmosphere. In the first filtering step, a first filterate is separated by filtering products of the first hydrolysis step.</p> |
