Mobil Polyrex 461 EP

Mobil industrial , United States

Multi-purpose Grease

Product Description

Mobil Polyrex™ 461 EP is a shear-stable polyurea grease with excellent extreme-pressure (EP) and load-carrying characteristics. The proprietary polyurea thickener system exhibits excellent resistance to oxidation and oil separation at operating temperatures as high as 160°C (320°F). With its outstanding high-temperature oxidation stability, load-carrying capability, shear stability, water resistance and wide operating temperature range, Mobil Polyrex 461 EP is an excellent heavy-duty grease for a wide array of industrial and construction applications.


Features and Benefits


Mobil Polyrex 461 EP contains a proprietary extreme-pressure (EP) additive package that provides load-carrying capability without degrading the thermal stability of the grease at high temperatures. Conventional sulfur- and phosphorus-base EP additives used in other multi-purpose greases begin to oxidize rapidly at temperatures above 250°F.Mobil Polyrex 461 EP, on the other hand, continues to provide a high level of wear and extreme-pressure protection up to 160°C (320°F) without rapid oxidation of the anti-wear or EP additives.



The proprietary polyurea thickener system inMobil Polyrex 461 EP exhibits excellent durability and stability when subjected to a mechanical shearing force. For example, in the ASTM D 217 cone penetration test, the consistency of Mobil Polyrex 461 EP changed by approximately one NLGI grade after being worked for 100,000 strokes - similar to the performance of high-quality lithium-complex greases, which are the benchmark for excellent shear stability. By contrast, competitive polyurea greases containing shear-unstable thickener technology can soften by three NLGI grades under the same test conditions. Good mechanical shear stability is important in roller bearing applications where excessive grease softening may lead to grease leakage or purging from the bearing.



The Mobil Polyrex 461 EP formulation is enhanced with water-resistant polymers that enable it to form a tenacious protective film in applications that are heavily contaminated with water. The excellent results obtained for Mobil Polyrex 461 EP in the water washout (ASTM D 1264) and corrosion (ASTM D 6138) tests demonstrate the grease's ability to stay in place and protect bearings in wet environments.


In summary, Mobil Polyrex 461 EP offers the following features and benefits:

• Outstanding high-temperature oxidation stability

• Excellent mechanical shear stability

• Thermally stable extreme-pressure (EP) protection

• Wide operating temperature range -20°C (-4°F) to 160°C (320°F)

• Excellent dispensability in automatic grease systems

• Resistant to water washout and protects bearings from corrosion



Mobil Polyrex 461 EP is an excellent heavy-duty grease for a wide array of industrial and construction applications.


Properties and Specifications




SKF Emcor Rust Test, Distilled Water, ASTM D6138


Copper Strip Corrosion, Rating, ASTM D4048


Base Oil Viscosity of Greases @ 40 C, mm2/s, AMS 1697


Dropping Point, °C, ASTM D2265


Water Washout, Loss @ 79 C, wt%, ASTM D1264


Rust, Rating, ASTM D1743


Penetration, 60X, 0.1 mm, ASTM D217


Four-Ball Extreme Pressure Test, Weld Load, kgf, ASTM D2596


Four-Ball Wear Test, Scar Diameter, mm, ASTM D2266



Health and safety

Health and Safety recommendations for this product can be found on the Material Safety Data Sheet (MSDS) @

All trademarks used herein are trademarks or registered trademarks of Exxon Mobil Corporation or one of its subsidiaries unless indicated otherwise.


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Typical Properties are typical of those obtained with normal production tolerance and do not constitute a specification. Variations that do not affect product performance are to be expected during normal manufacture and at different blending locations. The information contained herein is subject to change without notice. All products may not be available locally. For more information, contact your local ExxonMobil contact or visit
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