| abstract |
An aromatic polyester having improved heat resistance, hydrolysis resistance and alkali resistance which comprises recurring units of the general formula:n and recurring units of the general formula:n wherein R' and R 2 are an alkyl or alkoxyl group having 1 to 4 carbon atoms, R 3 , R4, R 5 and R 6 are the same or different and each is an alkyl or alkoxyl group having 1 to 4 carbon atoms, Cl or Br, x and y are an integer of 1 to 4, z, x', y' and z' are 0 or an integer of 1 to 4, and x is an alkylidene or cycloalkylidene group having 1 to 8 carbon atoms, -0-, -S-, -SO 2 - or -CO-. |