| 摘要 |
PROBLEM TO BE SOLVED: To obtain a fluoropolyimide optical material having a small coefficient of thermal expansion, a lowered permittivity and a lowered refractive index by reacting 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl with pyromellitic dianhydride. SOLUTION: 2,2'-Bis(trifluoromethyl)-4,4'-diaminobiphenyl is reacted with pyromellitic dianhydride in a polar organic solvent to obtain a polyamic acid. This acid is imidated to obtain a fluoropolyimide optical material comprising repeating units represented by the formula. |
