Solvent blends based on dipropylene glycol dimethyl ether for the production of alkyd and polyester resins by the azeotropic process

Solvent blends based on dipropylene glycol dimethyl ether (DPGDME) and non-HAP hydrocarbons were evaluated as xylene replacements for the preparation of alkyd and polyester resins by the solvent reflux process. Screening criteria included water partitioning properties, autoignition temperature, distillation profile, and water removal efficiency. A series of resins was also prepared by an identical procedure in order to compare the performance of the DPGDME solvent blends with that of the xylene control. Several of the DPGDME/hydrocarbon blends exhibited desirable partitioning properties and autoignition temperatures >350°C. These blends were close-boiling and when distilled in the presence of water, formed minimum boiling pseudo-heterogeneous azeotropes containing about 50% water. Size exclusion chromatography data showed that resins made with the DPGDME blends had essentially the same molecular weight distribution profile as those made with xylene.