Oil-resistant polyester synthesis process

The invention provides an oil-resistant polyester synthesis process, which comprises the following steps: S1, material preparation: preparing the following raw materials: terephthalic acid, glycol, sodium dimethyl isophthalate-5-sulfonate, an oil-resistant auxiliary agent and a polycondensation catalyst; S2, esterification: pressing terephthalic acid, glycol and the oil-resistant auxiliary agent into a first esterification vessel, heating and reacting and calculating the fraction in a rectifying tower, stopping esterification when esterification rate reaches 96.5%, and pressing high-purity nitrogen into a second esterification vessel; S3, addition of auxiliary materials: preparing an esterification fluid from sodium dimethyl isophthalate-5-sulfonate, and adding the esterification fluid into the second esterification vessel; preparing an EG solution from the polycondensation catalyst, and adding the EG solution into the second esterification vessel; heating and keeping for 1.5-2.5 h, and pressing high-purity n