Esters of maleinized fatty compounds as plasticizers

Some plant oil derived cyclohexane tricarboxylic acid triesters were synthesized and suggested as potential plasticizers based mainly on renewable feedstock. Methyl calendulate 1 and α-eleostearate 2 obtained from calendula oil and tung oil, respectively, as well as methyl oleate 3 were used as starting material. Reactions with maleic anhydride gave the corresponding Diels-Alder adducts 4 and 5 and ene adduct 6, which were converted by ring-opening reactions with various alcohols to the respective tricarboxylic acid triesters. Especially the cyclohexane tricarboxylic trimethyl triester 9 derived from Diels-Alder adduct 5 showed excellent absorption properties by PVC, superior to bis(2-ethylhexyl)phthalate (DEHP). Moreover, the commercially available Diels-Alder adduct of CLA 7 (Admergin acid") was ring-opened with methanol showing an absorption by PVC that was still higher compared to triester 9 although the viscosity was significantly higher.