Emulsification of oil based alkyd resins using the surfactant based inversion process

They say what is old is new, and for alkyds it is the case. Alkyds have changed from high volatile organic content (VOC) resins to waterbased emulsions for oxidative cure ambient temperature systems. Due to environmental, health and safety concerns (EH&S), traditional solvent based alkyds have been phased out. Initially replacing VOC containing solvents with non-VOC containing solvents worked, but current EH&S pressure has led to the emulsification of alkyds with very to low, to no solvent content.

Alkyd resins are polyester reaction of an alcohol  (traditionally from phthalic anhydride) and an acid group (traditionally fatty acids from natural oils). Due to the high molecular weight of the alkyd resin, solvents were needed to reduce viscosity to allow application of the alkyd based coating. The increase of the acceptance of water based resins has allowed main stream introduction of alkyd emulsions. However, taking traditional resins and just emulsifying them led to failure of the resin, mostly due to hydrolysis of the polyester linkage at the high ph of the coating (pH ~8.0-9.5). So modifying the resin to better resist hydrolysis and research into better surfactant systems to ease the inversion process from water in oil to oil in water. the Surfactant choice is critical in making a stable alkyd emulsion.

We will cover the modification of the alkyd resin, emulsification process, surfactant choice and finally test data on emulsions we created.