Overbased metal carboxylate complex grease and process for making

Abstract

Complex greases of overbased alkaline earth metal carboxylates are prepared by reacting an overbased alkaline earth metal salt of a fatty acid, wherein the alkaline earth metal salt has an alkaline earth metal content of at least 14.5% and a non-volatile matter content of at least 95% with conversion agents to form a grease precursor. The grease precursor is then reacted with complexing agents to form a predominantly vaterite containing non-Newtonian modified overbased metal carboxylate complex grease.

1 . An overbased metal carboxylate complex grease comprising:
 an overbased alkaline earth metal salt of a fatty acid, wherein the alkaline earth metal salt has an alkaline earth metal content of at least 14.5% and a non-volatile matter content of at least 95%;   conversion agents comprising:
 a hydrocarbon liquid; 
 water; 
 lime; 
 a polyol; and 
 a short chain carboxylic acid selected from the group consisting of acetic acid and propionic acid; and 
   at least one complexing agent selected from the group consisting of phosphoric acid, boric acid, a C 12 -C 24  aliphatic monocarboxylic acid and a C 12 -C 24  fatty acid.   
     
     
         2 . The complex grease of  claim 1 , wherein calcite is substantially not measurable in the grease. 
     
     
         3 . The complex grease of  claim 1 , wherein vaterite is the predominant form of calcium carbonate present in the grease. 
     
     
         4 . The complex grease of  claim 1 , wherein the fatty acid of the at least one complexing agent is 12-hydroxystearic acid. 
     
     
         5 . The complex grease of  claim 1 , wherein the fatty acid of overbased alkaline earth metal salt is oleic acid. 
     
     
         6 . The complex grease of  claim 1 , wherein an alkaline earth metal of the overbased alkaline earth metal salt is selected from the group consisting of calcium, barium, magnesium and strontium. 
     
     
         7 . The complex grease of  claim 1 , wherein the overbased alkaline earth metal salt is calcium oleate. 
     
     
         8 . The complex grease of  claim 1 , wherein the polyol is a glycol or a glycol ether selected from the group consisting of diethylene glycol monobutyl ether, triethylene glycol, dipropylene glycol, diethylene glycol monomethyl ether, ethylene glycol monobutyl ether, and mixtures thereof. 
     
     
         9 . A method of preparing a complex grease, the method comprising the steps of:
 providing a overbased alkaline earth metal salt of a fatty acid, wherein the alkaline earth metal salt has an alkaline earth metal content of at least 14.5% and a non-volatile matter content of at least 95%;   reacting the overbased alkaline earth metal salt of a fatty acid with conversion agents to form a Newtonian grease precursor, wherein the conversion agents comprise:
 a hydrocarbon liquid; 
 water; 
 lime; 
 a polyol; and 
 a short chain carboxylic acid selected from the group consisting of acetic acid and propionic acid; and 
   reacting the Newtonian grease precursor with at least one complexing agent to form a non-Newtonian complex grease, wherein the at least one complexing agent is selected from the group consisting of phosphoric acid, boric acid, a C 12 -C 24  aliphatic monocarboxylic acid and a C 12 -C 24  fatty acid.   
     
     
         10 . The method of  claim 9 , wherein calcite is substantially not measurable in the grease. 
     
     
         11 . The method of  claim 9 , wherein vaterite is the predominant form of calcium carbonate present in the grease. 
     
     
         12 . The method of  claim 9 , wherein the fatty acid of the at least one complexing agent is 12-hydroxystearic acid. 
     
     
         13 . The method of  claim 12 , wherein the fatty acid of overbased alkaline earth metal salt is oleic acid. 
     
     
         14 . The method of  claim 9 , wherein an alkaline earth metal of the overbased alkaline earth metal salt is selected from the group consisting of calcium, barium, magnesium and strontium. 
     
     
         15 . The method of  claim 9 , wherein the overbased alkaline earth metal salt is calcium oleate. 
     
     
         16 . A method of preparing a complex grease, the method comprising the steps of:
 providing a overbased alkaline earth metal salt of a fatty acid, wherein the alkaline earth metal salt has an alkaline earth metal content of at least 14.5% and a non-volatile matter content of at least 95%;   reacting the overbased alkaline earth metal salt of a fatty acid with conversion agents to form a thixotropic, non-Newtonian gelled grease precursor, wherein the conversion agents comprise:
 a hydrocarbon liquid; 
 water; 
 lime; 
 a polyol; and 
 a short chain carboxylic acid selected from the group consisting of acetic acid and propionic acid; and 
   reacting the non-Newtonian grease precursor with at least one complexing agent to form a non-Newtonian complex grease, wherein the at least one complexing agent is selected from the group consisting of phosphoric acid, boric acid, a C 12 -C 24  aliphatic monocarboxylic acid and a C 12 -C 24  fatty acid.   
     
     
         17 . The method of  claim 16 , wherein calcite is substantially not measurable in the grease. 
     
     
         18 . The method of  claim 16 , wherein vaterite is the predominant form of calcium carbonate present in the grease. 
     
     
         19 . The method of  claim 16 , wherein the fatty acid of the at least one complexing agent is 12-hydroxystearic acid. 
     
     
         20 . The method of  claim 19 , wherein the fatty acid of overbased alkaline earth metal salt is oleic acid. 
     
     
         21 . The method of  claim 16 , wherein an alkaline earth metal of the overbased alkaline earth metal salt is selected from the group consisting of calcium, barium, magnesium and strontium. 
     
     
         22 . The method of  claim 16 , wherein the overbased alkaline earth metal salt is calcium oleate.