Patent ID: 8835589

Claim:
A method of making a bio-based polyester resin, the method comprising: a) obtaining a bio-based glycerol that is a transesterification product of crude vegetable oil; b) obtaining a bio-based abietic acid; c) performing an esterification reaction between the bio-based glycerol and the bio-based abietic acid to form a 100% bio-based abietic acid-glycerol macromere, wherein the esterification comprises heating for at least 4 hours; and d) polycondensing the macromer with at least two diacids in the presence of a catalyst to obtain the bio-based polyester resin; wherein the bio-based polyester resin is at least 80 mol % bio-based and comprises, i) a softening point of about 90° C. to about 150° C., and ii) an acid value of about 8 to about 16 mgKOH/g.