The greases are obtained by mechanical dispersion of soap in petroleum oil. Soap is obtained when fat alkali used soaps are classified as sodium soap (prepared using NaOH), calcium soap (using Ca(OH2), lithium soap (LiOH) etc.
The soap thus obtained is used as a gelling medium the soap is added to hot lubricating with constant stirring to obtained greases.
The soap thickens the and is also known as thicker and decides the properties of greases.
Sometimes fillers like graphite, talc etc may or may not be added to these fillers to enhance the properties of greases.
The soap content in grease ranges from 7% to 18% but in a certain case, the soap content may range from 3% to 5% non-soap thickeners contain carbon black, silica gel etc.