The present invention provides an aromatic polyester which is obtained by condensation
polymerization reaction of terephthalic acid, 2,6-naphthalenedicarboxylic acid
and acylated product obtained by acylation of parahydroxybenzoic acid and hydroquinone
with fatty acid anhydride, wherein said aromatic polyester satisfy the following
conditions (A) to (D), and the acylation and/or the condensation polymerization
reaction are conducted in the presence of heterocyclic organic compound containing
at least two nitrogen atoms:
(A): Number of moles of a monomer unit derived from parahydroxybenzoic acid
(UNIT (1)) is 54-62 moles per 100 moles of UNIT (1), a monomer unit derived from
hydroquinone (UNIT (2)), a monomer unit derived from terephthalic acid (UNIT (3))
and a monomer unit derived from 2,6-naphthalenedicarboxylic acid (UNIT (4)) in total;
(B): Number of moles of UNIT (2) is 19-23 moles per 100 moles of UNIT (1),
UNIT (2), UNIT (3) and UNIT (4) in total;
(C): The molar ratio of UNIT (3) and UNIT (4), which is represented by the
following formula (I) is 0.23-0.35:
wherein [(3)] and [(4)] represent number of moles of respective UNIT
(3) and UNIT (4);
(D): Total number of moles of UNIT (3) and UNIT (4) is 0.95-1.05 moles per
one mole of UNIT (2).
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