Rubber process oil, both synthetic and natural, is used in the commercial production of products ranging from rubber bands to toys to giant tyres for various vehicles, including aircraft. Rubber Process Oils are used in the preparation of rubber compounds.

Rubber process oil is an oil composition with a kinematic viscosity at 100 °C ranging from 25 to 50 CST and containing less than 3% rubber. Polynuclear aromatic compounds are used as a process oil in the manufacture of rubber compounds, particularly aromatic rubbers.

Rubber process oil is used in a variety of rubber compounds. These aid in increasing filler dispersion and compound flow characteristics throughout the process.

Although the process oil is compatible with aromatic rubbers, it contains less toxic polynuclear aromatic compounds than traditional aromatic RPO. The use of the aforementioned oil composition results in rubber products of acceptable quality.