Effects of base oil type and water content on properties of calcium grease

Abstract

The purpose of this research is to study the effect of base oil type, water content, saponification rate and surfactant on properties of calcium grease. Calcium di-stearate is synthesized from saponification reaction of calcium hydroxide and fatty acid at 130 °c within opening process system. After that it and one type of base oil as naphthenic oil, paraffinic oil and mixed base oil of naphthenic and paraffinic oil, are mixed and then added with water when temperature is down to 100 °c. Smooth calcium grease is finally obtained. The obtained calcium greases are tested dropping point, water washout resistance and penetration number when it has been kept for 1, 7 and 30 days. The results of this research found that base oil type does not affect to grease’s consistency, dropping point, water washout resistance and fibers structure, but affect to grease's appearance. Calcium greases prepared from naphthenic oil and mixed base oil as N:P ratio; 80:20 and 70:30 are smooth, whereas it prepared from N:P ratio; 60:40 is slightly rough and prepared from paraffinic oil is very rough and grainy. Water content does not affect to calcium grease's dropping point and water washout resistance, but affect to grease's consistency, fibers structure and appearance. The proper water content for preparing calcium grease must not be at least 0.54 %. Saponification rate does not affect to calcium grease’s consistency, dropping point, water washout resistance and appearance. Finally, the research found that surfactant affect the grease has more smooth appearance, in the other hand, it affects to the grease's dropping point is lower and also fiber structure is unstable.