Petroleum resin is a kind of thermoplastic resin, which refers to the mixture of polymer molecules with different molecular weights of ethylene fraction and does not belong to dangerous goods. The melt viscosity of petroleum resin mainly affects the wetting ability of hot melt adhesives and pressure-sensitive adhesives. If the melt viscosity is too high, the wetting degree of hot melt adhesives and pressure-sensitive adhesives will decrease, and it will be difficult to bond hot melt adhesives and coat pressure-sensitive adhesives. If the melt viscosity is too low, on the one hand, it may cause the sedimentation of fillers in the hot melt adhesive system, resulting in uneven distribution of material components. On the other hand, it may cause the hot melt adhesive to be unfavorable for bonding due to the decrease of cohesive strength.

Classification of Petroleum Resins
(1) Petroleum resins can generally be classified into four types: C5 aliphatic, C9 aromatic, DCPD (cyclic diene) and pure monomers. The constituent molecules are all hydrocarbons, so they are also called hydrocarbon resins.
(2) According to different raw materials, petroleum resins are divided into aliphatic resins (C5), cycloaliphatic resins (DCPD), aromatic resins (C9), aliphatic/aromatic copolymer resins (C5/C9) and hydrogenated petroleum resins, such as C5 hydrogenated petroleum resin and C9 hydrogenated petroleum resin.

Main Applications of Petroleum Resins

(1) Paints
High softening point C9 petroleum resins, DCPD resins and C5/C9 copolymer resins are mainly used in paints. Adding petroleum resins to paints can increase the gloss of the paint and improve the adhesion, hardness, acid resistance and alkali resistance of the paint film.

(2) Rubber
Low softening point C5 petroleum resins, C5/C9 copolymer resins and DCPD resins are mainly used in rubber. These resins have good compatibility with natural rubber particles and have little effect on the rubber vulcanization process. Adding petroleum resins to rubber can play the roles of tackifying, reinforcing and softening. Especially the addition of C5/C9 copolymer resins can not only increase the adhesion between rubber particles, but also improve the adhesion between rubber particles and cord fabrics, and is suitable for high-requirement rubber products such as radial tires.

(3) Adhesives
Petroleum resins have good adhesion. Adding petroleum resins to adhesives and pressure-sensitive tapes can improve the adhesion, acid resistance, alkali resistance and water resistance of the adhesives, and can effectively reduce the production cost.

(4) Inks
Petroleum resins for inks are mainly high softening point C9 petroleum resins and DCPD resins. Adding petroleum resins to inks can play the roles of color development, quick drying and brightening, and improve printing performance.

(5) Asphalt
For coatings used in road signs and road markings, petroleum resins have good adhesion to concrete or asphalt roads, and have good wear resistance and water resistance, have good affinity with inorganic substances, are easy to coat, have good weather resistance, dry quickly and have high firmness, and can improve the physical and chemical properties of the coating and improve the ultraviolet resistance and weather resistance.