Petroleum resins are thermoplastic resins made from the C5 and C9 fractions, by-products of petroleum cracking, using sulfuric acid, anhydrous aluminum chloride, and boron trifluoride as catalysts through thermal polymerization. They are a newly developed chemical product. Depending on the raw materials and properties, they can be categorized as C5 petroleum resin, C9 petroleum resin, C5-C9 copolymer petroleum resin, and alicyclic petroleum resin. Due to their low cost, good compatibility, low melting point, and resistance to water, ethanol, and chemicals, they are widely used in a variety of industries and fields, including rubber, adhesives, coatings, papermaking, and inks.