Method for producing lubricating greases of lithium complex soaps and lithium-calcium-complex soaps

A method for producing lithium complex soap lubricating greases or lithium-calcium complex soap lubricating greases comprising at least the following steps:

• saponification of one or more dicarboxylic acids with one or two metal hydroxides, the one or two metal hydroxides being solids, according to one of the following three alternatives:
• (A1) saponification of the one or more dicarboxylic acids with lithium hydroxide, or
• (A2) saponification of the one or more dicarboxylic acids with lithium hydroxide and calcium hydroxide and one or more dicarboxylic acids, or
• (A3) saponification of the one or more dicarboxylic acids with calcium hydroxide,
• each in an aqueous environment comprising, more than 90 wt. % of water, calculated based on all liquid feedstocks used, further comprising heating to at least 40° C. to obtain one or more metal salts of the dicarboxylic acids, wherein both dicarboxyl groups of the dicarboxylic acids are substantially completely saponified;
• bringing the metal salt(s) into contact with one or more liquid hydroxycarboxylic acids or hydroxycarboxylic acids liquefied by heating and dissolving the metal salt(s) in the liquid or liquefied hydroxycarboxylic acids;
• adding base oil and applying heating before and/or after adding base oil;
• thereafter charging further metal hydroxides, wherein
• for alternative (A1) the further metal hydroxide is lithium hydroxide or calcium hydroxide;
• for alternative (A2) the further metal hydroxide is lithium hydroxide and calcium hydroxide or lithium hydroxide only or calcium hydroxide only;
• or
• for alternative (A3) the further metal hydroxide is lithium hydroxide;
• for saponification with the at least one hydroxycarboxylic acid;
• removal of water under heating;
• heating to a final temperature;
• and
• cooling down and addition of additional base oil.