| 摘要 |
<p>Polyamic acids and polyimides, which exhibit high light transmittance, high heat resistance of thermal decomposition temperatures of 300°C or above, excellent solvent solubility, and improved processability. Specifically, polyamic acids comprising repeating units represented by the general formula [1], characterized in that at least 10 % by mole of moieties A have a structure represented by the general formula [2]; or polyimides obtained by the cyclodehydration of the polyamic acids: [1] [wherein A is a tetravalent organic group; B is a divalent organic group; and n is a positive integer] [2] [wherein R<SUP>1</SUP> and R<SUP>2</SUP> are each independently hydrogen, halogeno, alkyl of 1 to 10 carbon atoms, haloalkyl of 1 to 10 carbon atoms, cycloalkyl of 3 to 8 carbon atoms, phenyl, or cyano; and a1 to a4 represent binding sites in the general formula [1], with the proviso that a1 and a3 must not simultaneously attach to the carboxyl groups and a2 and a4 must not simultaneously attach to the carboxyl groups].</p> |
