US Patent 7129301 Method for preparing a biodegradable copolyester

A method for preparing a biodegradable copolyester includes: (a) optionally preparing an aromatic prepolymer by reacting a first aromatic dicarboxylic compound with a first aliphatic glycol; (b) reacting the aromatic prepolymer with a second aromatic dicarboxylic compound and a second aliphatic glycol so as to form a first reaction product; (c) reacting the first reaction product with an aliphatic dicarboxylic compound so as to form a second reaction product; and (d) performing polycondensation of the second reaction product.