Patent ID: 6355738
Filing Date: 2002-03-12
Classification: C08G

Abstract:
A polyester which comprises dicarboxylic acid constituent units derived from terephthalic acid and naphthalenedicarboxylic acid and diol constituent units derived from ethylene glycol, and which has the following properties:constituent units derived from terephthalic acid are 40 to 99.5% by weight, constituent units derived from naphthalenedicarboxylic acid are 0.5 to 60% by weight and constituent units derived from isophthalic acid are 0 to 25% by weight, all based on the total amount of dicarboxylic acid constituent units (i), constituent units derived from ethylene glycol are 95 to 99.999% by weight and constituent units derived from a polyalkylene glycol having an alkylene oxide chain of 2 to 10 carbon atoms, wherein the degree of polymerization (n) of the polyalkylene glycol is in the range of 5 to 50, are 0.001 to 5% by weight, both based on the total amount of diol constituent units (ii), the intrinsic viscosity is in the range of 0.5 to 1.5 dl/g, the melting point (Tm (Â° C.)), as measured by a differential scanning calorimeter, satisfies the following formula (I): {1/527âˆ’0.0017Ã—ln(1âˆ’(mI+mN)/200)}âˆ’1âˆ’273254â€ƒâ€ƒ(I) wherein mI is a proportion (% by mol) of the constituent units derived from isophthalic acid to all of the dicarboxylic acid constituent units, and mN is a proportion (% by mol) of the constituent units derived from naphthalenedicarboxylic acid to all of the dicarboxylic acid constituent units, andthe amount of constituent units having a sequence of naphthalene acid-ethylene glycol-terephthalic acid (LNET (% by mol), as measured by 1H-NMR, satisfies the following formula (II): LNET&lE;0.5Ã—mNâ€ƒâ€ƒ(II) wherein mN is a proportion (% by mol) of the constituent units derived from naphthalenedicarboxylic acid to all of the dicarboxylic acid constituent units.