Patent ID: 6284866
Filing Date: 2001-09-04
Classification: C08G,Y10T

Abstract:
A method of preparing a high molecular weight copolyester bottle resin that has excellent melt processing characteristics, comprising:reacting a terephthalate component and a diol component to form a modified polyethylene terephthalate, whereinthe terephthalate component includes at least about 4 mole percent diacid or diester comonomer with the remainder being terephthalic acid or dimethyl terephthalate, andthe diol component is present in excess of stoichiometric proportions and includes at least about 2 mole percent diol comonomer with the remainder being ethylene glycol;thereafter copolymerizing the modified polyethylene terephthalate in the melt phase to an intrinsic viscosity of between about 0.25 dl/g and 0.40 dl/g to thereby form a copolyester prepolymer having an average apparent crystallite size of less than 9 nm;thereafter forming the copolyester prepolymer into chips; andthereafter polymerizing the copolyester prepolymer chips in the solid phase to form a high molecular weight bottle resin with an intrinsic viscosity of at least about 0.70 dl/g and a solid phase density of less than 1.413 g/cc.