Pressure Sensitive Adhesives Based on Oleic Acid

Existing pressure sensitive adhesives (PSA) are mostly based on petrochemical-based polymers. This study reveals a new class of bio-based polymers that can be used as PSA. The polymers are hydroxyl-containing polyesters from the step-growth polymerization of epoxidized oleic acid (EOA), an AB-type monomer containing both a carboxylic acid group (A) and an epoxy group (B). The monomer is derived from epoxidation of renewable methyl oleate followed by selective hydrolysis of the ester group. The polymers (PEOA) of EOA were characterized for their chemical structure and molecular weight. The PEOA after being cured with a very small amount of a crosslinking agent could serve as a PSA with high peel strength, high tack force, superior shear resistance, excellent aging resistance, and excellent thermal stability. The PSA contains 99 wt% of green renewable materials. The PSA were also characterized for their viscoelastic properties and thermal properties.