Introduction to Grease

What is Grease?

Base Stock + Additives + Thickener = Grease

• A solid to semi solid product of dispersion of a thickening agent in a liquid lubricant. Other ingridients imparting special properties may be included.


• To dicrease dripping, spattering, and leakage of lubricants.


• To seal out contaminants.


• When oil circulation is impractical.


• To suspend oil additives.


• For intermittent, extreme, and special operation conditions.


• Sealed for life operations.

What makes up a grease?

• Thickener may be soap, polyurea, or clay


• Base fluid may be mineral or synthetic


• Many different additives may be used

Types of Grease Thickeners

1. Complex Soap Thickeners Soap Based Thickeners

• Fatty Acid + Metal Hydroxide = Soap


• Soap named according to metal hydroxide (i.e. Lithium)


• Fatty Acid + Di-Acid + Metal Hydroxide = Complex Soap


• Di-Acid increases melting point and shear stability of soap

2. Polyurea Thickeners

• Non-soap thickeners


• Inherent anti-oxidant properties

3. Clay (Bentonite) Thickeners

• Do not melt at high temperatures