TDAE T400 vs RPO 220: Which Rubber Process Oil Does Your Compound Actually Need?

Two REACH-compliant process oils, similar price band, both used as extenders for synthetic rubber. It would be easy to treat them as interchangeable and buy on price.

They are not interchangeable, and the parameters that separate them are not the obvious ones. Here is the comparison as a compounder would read it.

Side by side

Four things in that table matter more than the rest.

1. Aromaticity — the real dividing line

Aniline point is an inverse measure of aromaticity: the lower it runs, the more aromatic the oil. T400 sits at 64–75 °C. RPO 220 is specified only as a maximum of 95 °C, which puts it in a meaningfully less aromatic band. The Ca figures point the same way — minimum 25% against minimum 20%.

This is the difference that determines where each oil belongs. Higher aromaticity means stronger solvency for carbon black and silica, better compatibility with SBR and BR, and — critically for tread compounds — a larger contribution to wet grip. Our guide on how process oil moves wet grip and rolling resistance covers the mechanism in detail.

For a tread compound sold on wet performance, that gap is not a rounding difference. For a conveyor belt cover or a moulded industrial article, it may be irrelevant.

2. RPO 220 is heavier at 100 °C, not lighter

This one surprises people who assume the cheaper oil is the thinner one. At 100 °C, RPO 220 runs 20–30 mm²/s against T400's 16–23. RPO 220 is the more viscous product at operating temperature.

It matters for mixing behaviour and for how the oil disperses in a highly filled compound. Do not assume a like-for-like viscosity substitution when moving between them.

3. Pour point runs the opposite way to expectations

T400 has a pour point up to 30 °C. RPO 220 is capped at 15 °C.

So the more aromatic, technically higher-grade oil is the harder one to handle. T400 is semi-solid at ordinary ambient temperatures across most of Asia and will need heated discharge in nearly every destination. RPO 220 is more forgiving — still semi-solid in cooler conditions, but with a 15 °C margin that makes tropical-port handling considerably simpler.

There is a packing consequence too: T400 is available in ISO tanks, RPO 220 is not. For a buyer without heated receiving facilities, that combination — lower pour point, but no ISO tank option — needs thinking through before the order rather than at discharge. Our shipping and heating guide covers the planning.

4. What RPO 220 does not specify

RPO 220's data sheet carries no glass transition temperature and no viscosity gravity constant. That is not a defect; it reflects what the grade is sold for.

But it has a practical consequence. If your formulation is designed around a target compound Tg — which is standard practice in tread development — you cannot model RPO 220's effect without generating that data yourself. T400 gives you −55 to −45 °C to work with. For tread work, that alone may decide the question.

Choosing between them

Use SANYANG TDAE T400 where: the compound is a tyre tread or sidewall; wet grip is a performance claim; the polymer system is SBR or BR and needs strong solvency; filler loading is high; or the formulation is specified around a target Tg.

Use SANYANG RPO 220 where: the application is general rubber goods, conveyor belts, hoses, profiles or moulded articles; full aromaticity is not required; cost per tonne is a primary driver; or handling constraints favour the lower pour point.

Do not substitute one for the other in an existing formulation without reformulation work. The aromaticity gap will change cure behaviour, filler dispersion and hardness. The adjustment is usually manageable, but it is a formulation project, not a purchase order change.

What both share

Both are Malaysian origin, supplied ex-Pasir Gudang. Both carry benzo[a]pyrene below 1 mg/kg and sum of PAHs below 10 mg/kg, measured to EN 16143, and both comply with REACH including Commission Regulation (EU) 2015/326. Both come with batch-specific certificates of analysis, and both have a 24-month shelf life.

For a manufacturer exporting finished goods to Europe, that compliance parity is the point: the choice between them is a technical and commercial decision, not a regulatory one.

Frequently Asked Questions

Sanyang Petroleum supplies SANYANG TDAE T400 and SANYANG RPO 220 from Malaysia to tyre manufacturers, retreaders and rubber goods producers across Southeast Asia, South Asia and the Middle East, with batch-specific COAs and EN 16143 PAH analysis as standard. Contact info@sanyangpetroleum.com or submit an RFQ.