Overbased Calcium Sulfonate
High-TBN overbased calcium sulfonate detergent — the acid-neutralizing TBN reserve and detergency backbone for engine oils, marine cylinder oils and industrial lubricants. Multiple TBN grades, bulk supply worldwide.
The high-TBN detergent that neutralizes acid and keeps engines clean
Overbased calcium sulfonate is the workhorse detergent of the lubricant industry — the primary source of the TBN reserve that protects engines from acidic wear over long service.
It carries a large reserve of colloidally dispersed calcium carbonate, which neutralizes the acids formed during combustion and oil oxidation — the basis of the oil's Total Base Number (TBN). At the same time it acts as a detergent, keeping pistons, ring grooves and metal surfaces clean by suspending deposit precursors, and it contributes rust and corrosion protection. Overbased calcium sulfonate is essential in passenger car and heavy-duty engine oils, marine cylinder and trunk-piston oils, and many industrial lubricants. It belongs to the sulfonate detergent family and is typically used alongside phenate and salicylate detergents to balance TBN, cleanliness and sulphated ash.
Overbased calcium sulfonate — typical properties
Representative typical values across the overbased calcium sulfonate grade range. These are indicative only — exact values vary by grade and are confirmed on the product Technical Data Sheet (TDS) and batch Certificate of Analysis (COA).
| Property | Typical Value | Method / Note |
|---|---|---|
| Appearance | Brown viscous liquid | Visual |
| Total Base Number (TBN) | ~300–500 mg KOH/g | ASTM D2896 · grade-dependent |
| Calcium content | ~12–16 wt% | Grade-dependent |
| Kinematic viscosity (100°C) | ~100–600 mm²/s | ASTM D445 · grade-dependent |
| Flash point (COC) | > ~170 °C | ASTM D92 |
| Density (15°C) | ~1.1–1.3 g/cm³ | Typical |
| Sulphated ash | High (overbased) | ASTM D874 |
Typical values for guidance only — not a specification. Request the TDS for the specific grade and TBN level you need; the COA reports actual measured values for your batch.
Where overbased calcium sulfonate is used
Engine Oils (PCMO & HDDO)
Primary TBN source and detergent for passenger car and heavy-duty diesel engine oils — neutralizes combustion acids over long drains. See engine oil additives and diesel engine oil.
Marine Cylinder & System Oils
Very high TBN grades neutralize the strong acids from high-sulphur marine fuel — a core component of marine engine oils. See industrial & marine additives.
Industrial Lubricants
Provides detergency, acid control and rust protection in industrial engine oils and certain gear and circulating oils.
Rust Preventives & Greases
Calcium sulfonate also serves in rust-preventive formulations and as a base for calcium sulfonate complex greases.
Why formulators choose overbased calcium sulfonate
High TBN reserve
Large acid-neutralizing reserve per unit of additive — reach your finished-oil TBN target efficiently, even for high-sulphur fuel applications.
Detergency + rust protection
Keeps pistons and metal surfaces clean while contributing corrosion protection — multifunctional performance from one additive.
Multiple TBN grades
A range of TBN levels lets you match the exact reserve your engine, marine or industrial oil specification requires.
From sample drum to ISO tank
Sinolook supplies overbased calcium sulfonate at any scale, from formulation samples to commercial bulk, to over 60 countries.
Frequently asked questions
What is overbased calcium sulfonate used for?
1. Neutralizes acids from combustion and oxidation (providing the oil's TBN reserve)
2. Keeps surfaces clean by suspending deposit precursors
3. Provides rust and corrosion protection
The excess calcium carbonate it carries (the overbased portion) is the reserve that neutralizes acids over the oil's service life — which is why high-TBN overbased calcium sulfonate is essential for oils running on high-sulphur fuels and long drain intervals.
What TBN does overbased calcium sulfonate provide?
Higher TBN means more acid-neutralizing reserve per unit of additive, letting formulators reach a target finished-oil TBN with less additive. Sinolook supplies a range of TBN grades so you can match the reserve your engine oil or marine oil specification requires.
What is the difference between neutral and overbased calcium sulfonate?
Overbased calcium sulfonate carries a large reserve of colloidally dispersed calcium carbonate, giving it a high TBN (hundreds of mg KOH/g) and making it a powerful acid-neutralizing detergent.
In a finished oil, neutral sulfonate is chosen mainly for corrosion protection, while overbased sulfonate is chosen for detergency and TBN reserve. Many formulations use both.
How much overbased calcium sulfonate is used in engine oil?
Marine cylinder oils use much higher levels to reach the very high TBN those oils require. Always design to your finished-oil TBN target, sulphated ash limit and the detergent's TBN as stated on the TDS.
Can Sinolook provide TDS, MSDS and COA?
Sinolook supplies overbased calcium sulfonate in drum, IBC tote, flexitank and ISO tank quantities to over 60 countries. Email sales@sinolook.com or message us on WhatsApp for documentation and a quotation.
Request overbased calcium sulfonate from Sinolook
Tell us your target TBN, application and volume — we'll send the TDS, a batch COA and a delivered quotation within 24 hours.
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