Propylene glycol is an important raw material for unsaturated polyester, epoxy resin, and polyurethane resin. The amount in this area accounts for about 45% of the total consumption of propylene glycol. This unsaturated polyester is used in large quantities for surface coatings and reinforced plastics. Propylene glycol has good viscosity and hygroscopicity and is non-toxic, so it is widely used as a moisture absorbent, antifreeze, lubricant, and solvent in food, medicine, and cosmetic industries. In the food industry, propylene glycol and fatty acids react to produce propylene glycol fatty acid esters, which are mainly used as food emulsifiers; propylene glycol is an excellent solvent for seasonings and pigments. In the pharmaceutical industry, propylene glycol is often used as a solvent, softener, and excipient for the manufacture of various ointments and ointments. Because propylene glycol has good compatibility with various spices, it is also used as a solvent and softener for cosmetics.