Patent ID: 6320014
Filing Date: 2001-11-20
Classification: B29B,C08G

Abstract:
Polyester pellets made of a polyester which comprises dicarboxylic acid constituent units derived from dicarboxylic acids containing terephthalic acid and isophthalic acid and diol constituent units derived from diols containing ethylene glycol and 1,3-bis(2-hydroxyethoxy)benzene, and which has the following properties:constituent units derived from terephthalic acid are 50 to 99% by mol and constituent units derived from isophthalic acid are 1 to 50% by mol, both based on the total amount of dicarboxylic acid constituent units (i),constituent units derived from ethylene glycol are 25 to 99.5% by mol and constituent units derived from 1,3-bis(2-hydroxyethoxy)benzene 0.5 to 75% by mol, 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, andthe melting point (Tm (.degree. C.)), as measured by a differential scanning calorimeter, satisfies the following formula (I):[1/527-0.0017.multidot.ln(1-(m.sub.I +m.sub.B)/200)].sup.-1 -273<Tm.ltoreq.265 (I)wherein m.sub.I is a proportion (% by mol) of the constituent units derived from isophthalic acid to all of the dicarboxylic acid constituent units, and m.sub.B is a proportion (% by mol) of the constituent units derived from 1,3-bis(2-hydroxyethoxy)benzene to all of the diol constituent units;said polyester pellets having a density of not less than 1,350 kg/m.sup.3.