Process oils are refined from crude petroleum through a series of steps that remove impurities and isolate desired hydrocarbon structures. The refining method determines the oil’s composition (aromatic, naphthenic, or paraffinic), and directly impacts its performance in rubber, plastic, and other formulations. Process oils are used in a variety of industrial applications primarily as processing aids, carriers, or modifiers during the manufacturing of rubber, plastics, and other materials. Here’s a breakdown of how they are used:
- Rubber and Tire Manufacturing
- Function: Process oils are added to rubber compounds to improve processability, flexibility, and filler dispersion. They act as major plasticizers for NR, BR, IIR, and SBR.
- Why: They reduce viscosity, making the rubber easier to shape and mold.
- Types Used:
- Aromatic oils – less common now due to toxicity concerns
- Naphthenic oils – Best for non-polar elastomers
- Paraffinic oils – gives good oxidation resistance
- Plastics and Polymer Processing
- Function: Used as a plasticizer or carrier fluid in TPEs (thermoplastic elastomers), PVC, and other polymers.
- Why: Enhance softness, flexibility, and extrusion/molding properties.
- Adhesives, Sealants, and Coatings
- Function: Serve as diluents or softeners to adjust flow and application characteristics.
- Why: Improve workability, especially in pressure-sensitive adhesives or sealants.
- Chemical Industry (Carrier/Reaction Medium)
- Function: Act as an inert carrier or reaction medium for chemical additives or reactions.
- Why: Ensure even distribution of active ingredients or heat transfer in certain formulations.
- Lubricants and Oils (as a base or modifier)
- Function: Serve as a component in lubricant formulations or as a blending oil.
- Why: Tailor viscosity, pour point, and solvency.
- Personal Care
- Function: Acts as an occlusive agent – forms a barrier to prevent moisture loss from skin and helps spread active ingredients evenly,.
- Why: They are Inert, colorless, odorless and tasteless.
- Types Used:
Comparison of Process Oils
| Type | Base Composition | Key Properties | Typical Applications | Pros | Cons |
| Aromatic | High aromatic hydrocarbons | High solvency, dark color, good compatibility with polar rubbers (e.g., SBR, NR) | Tires, conveyor belts, molded rubber | Excellent filler dispersion, low cost | Contains PAHs (toxic), regulatory restrictions |
| Naphthenic | Cycloalkanes + aromatics | Moderate solvency, lighter color, good low-temp performance | Sealants, hoses, adhesives, TPEs | Better color stability, good balance of solvency/flexibility | Lower oxidation resistance than paraffinic |
| Paraffinic | Linear and branched alkanes | Low solvency, high viscosity index, excellent oxidation stability | Thermoplastics, EPDM rubber, synthetic rubbers | Excellent heat resistance, UV stability | Poor compatibility with polar rubbers |
| Vegetable-based | Natural oils (e.g., soybean) | Renewable, biodegradable, compatible with certain bio-polymers | Sustainable rubbers, eco-friendly sealants | Biodegradable, low toxicity | Higher cost, potential for odor or instability |
| White oils | Refined paraffinic/naphthenic | Highly purified, odorless, colorless, food/pharma-grade | Food packaging, medical elastomers, cosmetics | Non-toxic, meets FDA/USP standards | More expensive than technical-grade oils |