Lithium Complex Grease

High temperature version of Lithium Grease - the de-facto high temperature bearing grease

The key advantages include:

  • Does not melt until at least 260°C
  • Shear stable
  • Made from widely available commodity raw materials

Limitations:

  • None, but if one sets the height bar high, one could argue that it is not as water resistant as calcium and aluminium greases

Manufacturing Principle:

React Lithium Hydroxide with mono and bi-valent acids, holding for a while at just over 100°C to allow complexing to happen, then heat up to almost 200°C to drive off water content.  Only dilute with a small amount of oil when cooling or complex will break up leaving a mono-soap structure.  Mill and then optionally, filter and de-aerate.

Recommended Process Vessel(s):

  • Ideal:  Use pressurised autoclave, ideally fitted with bottom entry turbomixer or disperser to prevent unreacted bi-valent acid buildup for the heated half of the process and finishing kettle connected to both heating and cooling circuits for the cooling half
  • Cost Effective:  Use a single grease kettle for the whole process, but cooling circuit as well as heating circuit will be needed to prevent extended cooling down timescale

Aluminium Complex Grease

High Temperature, highly water-resistant grease

The key advantages include:

  • Does not melt until at least 260°C
  • Highly water resistant
  • Adheres well to metal
  • Can be made for food processing applications if the right base oil is used

Limitations:

  • Can get hot at high speeds
  • Requires specialist raw material (Aluminium donor, e.g. Kolate)
  • Can be difficult to eliminate unreacted acid unless samples are checked with an infra-red spectrometer

Manufacturing Principle:

Aluminium donor is reacted with mono and bi-valent acids in oil with heat up to just over 200°C.  Unreacted acid needs to be checked for before cooling down by using an infra-red spectrometer.  Do not add a significant amount of oil during cooling or complex structure is liable to break down.  Do not mill. Filtering and de-aeration can be done as an option.

Recommended Process Vessel:

  • Heated Grease Kettle - pressure is not needed

Calcium Sulphonate Complex Grease

High Temperature, highly water-resistant grease with good shear stability

The key advantages include:

  • Does not melt until about 300°C
  • Highly water resistant
  • Thickener doubles as a EP additive and corrosion inhibitor giving the grease a high performance, even without additives
  • High specific gravity makes it possible to do a negative buoyancy grade, advantageous in marine applications where it will sink rather than float on water, reducing pollution issues.

Limitations:

  • Can get hot at high speeds
  • Requires specialist raw material in the form of Calcium Suphonate, problem can be made worse as some calcium sulphonate manufacturers also make the grease, meaning your main raw material supplier may also be your main competitor! Effective fume extraction/vapour control needed to minimise air pollution

Manufacturing Principle:

React calcium sulphonate with mono and bi-valent acids and alcohol.  Must be held at just below alcohol's boiling point for two hours for complexing to happen, then heat up to almost 200°C to drive off water content.  Do NOT dilute with oil when cooling or complex will break up leaving a mono-soap structure.  Do not mill.  Filtering and de-aeration can be done as an option.

Recommended Process Vessel:

  • Heated and cooled Grease Kettle, ideally with bottom entry turbomixer or high speed disperser to prevent thickener accumulating at the bottom of the kettle.  Also the bottom entry unit helps ensure the temperature is the same everywhere in the kettle, which is important for the two hour hold during complexing.  Pressure is not needed