Rubber Process Oil (RPO)

About This Product

Tyre makers use Rubber Process Oil to extend and soften tread, sidewall and carcass compounds, and it serves equally in retread rubber, conveyor belt covers, hoses and extruded profiles, provided the article can tolerate a dark oil that stains. Oils of this aromatic kind became the established softener for tyre rubber because of three properties: high density, strong solvating power towards unsaturated elastomers and ready wetting of carbon black.

Plan for the pour point before the first delivery. The limit is max +27 °C, so in a cool building the oil may be thick or semi-solid, and tanks are normally heated, transfer lines trace-heated and drums warmed. With specific gravity in the range 0.961 – 1.046 the oil weighs about the same as water, which needs to be allowed for in volumetric dosing and in calculating compound density. The flash point, min 204 °C by Cleveland open cup, limits fuming and weight loss at internal mixer and extruder temperatures.

Compounders judge aromaticity, and so compatibility, by the viscosity gravity constant. Worked out from density and viscosity, VGC rises as aromatic content rises, and the band of 0.94 – 0.99 sets this oil clearly apart from paraffinic and naphthenic types and signals that it will suit SBR, BR and natural rubber. The specification allows anywhere from 14.0 to 37.0 cSt at 100 °C, a wide range, so fix the viscosity for each compound at the offer stage. Oil from the upper end evaporates and migrates less; oil from the lower end softens the batch more quickly and brings torque down sooner in the mixer.

The oil itself is a by-product of base oil refining. Heavy lube distillate is solvent extracted to remove condensed aromatic and polar compounds that would harm a lubricant's viscosity index and resistance to oxidation, and the rejected extract is exactly what suits rubber. In the process oil line-up it sits at the heavy end alongside High Extract Oil, with Low Extract Oil the lighter extract; Carbon Black Feedstock Oil is different again, since it is fed to a reactor instead of being mixed into a compound. Follow the SDS, which gives the hazard classification of this aromatic extract, for storage and handling.

BG Petro Chemicals ships RPO of Pakistan origin in drums, IBC tanks or ISO tanks and can arrange other packaging for the receiving plant. A certificate of analysis is issued with every lot, and the technical datasheet and SDS are available on request.