| 摘要 |
PROBLEM TO BE SOLVED: To obtain a polymide capable of expressing excellent film formability, excellent adhesivity to glass substrates, excellent thermal stability, excellent liquid crystal orientation and high electric voltage retention and useful for liquid crystal cells for thin film transistors, etc., by introducing specific structural units having cyclobutane rings. SOLUTION: A polyamic acid as the precursor of the polyimide has a weight- average mol.wt. of 5000-500000. The polyimide comprises (S1 ) structural units of formula I [A is a divalent organic group; X is H, a (halogenated) alkyl, an alkoxy, a haogen, cyano, phenyl, a cycloalkyl] preferably in an amount of >=5 mol.% and (S2 ) structural units of fomrula II (B is a tetravalent organic group). The polyimide is obtained by reacting compounds of formulas III and IV with a compound of formula V in a solvent and subsequently heating the obtained polyamic acid. |
