process oil - oil that serves as a temporary or permanent component of a manufactured product. Aromatic process oils have good solvency characteristics; their applications include proprietary chemical formulations, ink oils, and extenders in synthetic rubbers. Naphthenic process oils are characterized by low pour points and good solvency properties; their applications include rubber compounding, printing inks, textile conditioning, leather tanning, shoe polish, rust proofing compounds, and dust suppressants. Paraffinic process oils are characterized by low aromatic content and light color; their applications include furniture polishes, ink oils, and proprietary chemical formulations. See proprietary product.