Calcium carbonate based sulfonate grease compositions and method of manufacture

A calcium sulfonate complex grease composition comprising the following ingredients:

• oil-soluble overbased calcium sulfonate having 28% to 36% dispersed calcium carbonate and 0% to 8% residual calcium oxide or calcium hydroxide dispersed therein, such amounts by weight of the oil-soluble overbased calcium sulfonate;
• crystalline calcium carbonate added in addition to the amount of dispersed calcium carbonate contained in the oil-soluble overbased calcium sulfonate;
• one or more converting agents;
• one or more complexing acids;
• wherein no calcium oxide or calcium hydroxide is added in addition to any amount of residual calcium oxide or calcium hydroxide contained in the oil-soluble overbased calcium sulfonate.

A simple calcium sulfonate grease composition comprising the following ingredients:

• around 10% to 45% overbased calcium sulfonate containing calcium carbonate dispersed therein, wherein the dispersed calcium carbonate is in an amorphous state when the overbased calcium sulfonate is first added to the other ingredients and is converted to a crystalline state in the final simple grease product;
• 2% to 20% crystalline calcium carbonate added in addition to the amount of amorphous calcium carbonate contained in the overbased calcium sulfonate;
• wherein the simple grease has a worked penetration between 240 and 475;
• and
• wherein the overbased calcium sulfonate contains 0% to 8% residual dispersed calcium oxide or calcium hydroxide and wherein no additional calcium oxide or calcium hydroxide is separately added.

A method for making an overbased calcium sulfonate complex grease comprising the steps of:

• providing 10 to 45 parts overbased calcium sulfonate having 28% to 36% amorphous calcium carbonate and 0% to 8% residual calcium oxide or calcium hydroxide dispersed therein;
• providing 2 to 20 parts of crystalline calcium carbonate as a separately added ingredient in addition to the amount of amorphous calcium carbonate contained in the overbased calcium sulfate;
• mixing the overbased calcium sulfonate with 30 to 60 parts of a base oil, the separately added crystalline calcium carbonate, 2 to 10 parts water, and 0.5 to 5 total parts of one or more other converting agents to form a pre-conversion mixture;
• converting the pre-conversion mixture to a converted mixture by heating until conversion of the amorphous calcium carbonate contained in the overbased calcium sulfonate to a crystalline form has occurred;
• and
• mixing 2.8 to 11 total parts of one or more complexing acids with the pre-conversion mixture, converted mixture, or both;
• wherein no additional calcium oxide or calcium hydroxide is added in addition to any amount of residual calcium oxide or calcium hydroxide contained in the overbased calcium sulfonate and the separately added crystalline calcium carbonate is the sole calcium containing base added as a separate ingredient for reacting with the one or more complexing acids;
• and
• wherein the amount of amorphous calcium carbonate and residual calcium oxide or calcium hydroxide is by weight of the overbased calcium sulfonate and all other amounts are by weight of the final complex grease product.