Ask three suppliers which thickener is “best” and you will get three different answers – usually the one they sell. The honest answer is that each thickener family wins in a specific environment. Here is the comparison that actually matters, field-tested across our 28 years of production.
Lithium (the all-rounder)
Lithium 12-hydroxystearate thickeners cover the widest application window at the lowest cost. Dropping point around 190-200 °C, good water resistance (not great), excellent shear stability, and compatible with most other lithium and lithium-complex greases.
Choose lithium when: the application is general machinery, temperature stays under 120 °C continuous, and cost per kilogram matters. Our lithium line covers NLGI 000 to 3, including EP and semi-fluid versions.
Polyurea (the high-temperature specialist)
Polyurea thickeners are sheared from an in-situ reaction, giving a dropping point of 250 °C+ and outstanding oxidation resistance – the grease does not need antioxidant top-ups to survive long bearing life. Electric motor manufacturers standardised on polyurea decades ago for “sealed for life” bearings.
Choose polyurea when: relubrication is difficult or impossible (sealed bearings), temperatures run 150-200 °C continuous, or you need 20,000+ hour bearing life. The trade-offs: polyurea does not mix safely with lithium or calcium greases, and it is more expensive per kilogram.
Calcium (the water fighter)
Conventional calcium grease softens above 80-90 °C but is nearly waterproof. Anhydrous calcium – the type we produce – pushes the dropping point to 140-150 °C while keeping the exceptional water washout resistance: under 5% loss in the ASTM D1264 test.
Choose calcium when: water is everywhere – mining slurry, marine equipment, water pumps, food processing washdowns. Nothing else survives constant water contact as well at this price point.
Head-to-head summary
| Property | Lithium | Polyurea | Calcium (anhydrous) |
|---|---|---|---|
| Dropping point | 190-200 °C | 250 °C+ | 140-150 °C |
| Max continuous temp | 120 °C | 180-200 °C | 110 °C |
| Water resistance | Good | Fair-good | Excellent |
| Shear stability | Excellent | Good | Very good |
| Pumpability (centralised) | Very good | Good | Good |
| Mixing compatibility | Wide | Narrow | Wide (soaps) |
| Relative cost | Low | High | Medium |
The mixing trap
One warning that outranks everything above: polyurea and lithium/calcium greases are generally incompatible. Topping a polyurea-filled motor bearing with lithium grease can liquefy the matrix and dump both into the windings. If you inherit equipment and do not know what is inside, flush or relubricate aggressively until the old grease is purged.
We manufacture all three families and will tell you honestly which one your application needs – sometimes that means recommending the cheaper one. Request samples of each for side-by-side bench testing.