Patent ID: 7838091

Claim:
An aromatic polyamide compound which is a copolymer comprising repeating units represented by the following formula I and formula II: wherein, A is —SO 2 —, —CF 2 —, or —C(CF 3 ) 2 —, A′ is —CONH— or —NHCO—, which is in the meta-meta- or meta-para-position with respect to an amine group, R, R′, R″ and R′″ are each independently any one of —H, —F, —Cl, —I, —NO 2 , —CN, alkoxy having 1 to 4 carbon atoms, or —CF 3 and may be identical to or different from each other, at least one of the R″ and R′″ is a polar group selected from —F, —Cl, —I, —NO 2 , and —CN, and Ar and Ar′ are each independently a benzene ring or a naphthalene ring in the meta- or para-position and may be identical to or different from each other; and wherein the repeating unit represented by the formula II is contained in an amount ranging 15-50% by mole based on the total repeating units of the copolymer, and an optical film prepared from the aromatic polyamide compound has a YI of 10 or less, and a YI, after a heat treatment at 250° C. for 30 minutes, of also 10 or less for a film thickness of 60 to 100 μm.