Grease copositions

Abstract

A grease composition comprising base oil and as thickener calcium complex soap and lithium soap is disclosed. A higher fatty acid, an aromatic monocarboxylic acid and a lower fatty acid are used as carboxylic acids constituting the calcium complex soap and lithium soap. The grease composition has a high dropping point and excellent shear stability, and exhibits thermal stability and long bearing life.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a grease composition. More specifically, the present invention relates to a heat-stable lithium-containing calcium complex-based grease composition which has a high dropping point and excellent shear stability, and exhibits long bearing life.BACKGROUND OF THE INVENTION[0002]With the advancement of mechanical technology such as automobiles or electric equipment, operating conditions are using higher temperatures and are getting harsher every year with the minimisation of size and weight and increase in output of various types of equipment. Consequently, there is an increased demand for improved performance of grease for use in various equipment under a high temperature. Grease compositions which have a high dropping point and excellent thermal stability have been proposed.[0003]In addition to the improvement in grease performance under a high temperature, there is also an increased demand for materials and the like which ar...

AI Technical Summary

Benefits of technology

The lithium-containing calcium complex grease composition described in this patent has several benefits. It has a high dropping point, meaning it has good consistency and can be used in high temperature environments. It is also safe, environmentally friendly, and low-cost. Additionally, it has excellent shear stability and is long-lasting.

Problems solved by technology

With the advancement of mechanical technology such as automobiles or electric equipment, operating conditions are using higher temperatures and are getting harsher every year with the minimisation of size and weight and increase in output of various types of equipment.

However, since lithium, which is the starting material of lithium grease, is not limited in its use to grease and is variously used in other fields, there is concern about resource depletion or a steep rise in cost in the future due to a recent increase in demand.

In addition, lithium complex grease has problems in that the production procedure is complex and a longer time is required because the reaction of two kinds of aliphatic acid comprises two stages.

However, since an amine compound such as aniline, which is used as the starting material, is extremely toxic, extra care should be taken when handling for production, and therefore there is a safety problem.

However, greases using calcium soap as a thickener usually have a poorer dropping point and thermal resistance than lithium grease, lithium complex grease or urea grease, and therefore greases using calcium soap do not meet requirements as grease suitable for current operating conditions.

However, there are problems in that a suitable consistency cannot be maintained if the added amount of thickener is small, and there is a restriction in the form of dibasic acid, especially terephthalic acid, which is used as a starting material, and the terephthalic acid has to be introduced at a high temperature of 120° C. for production.