Lubricating Greases Containing Lignosulfonate, The Production Thereof, and the Uses Thereof

Abstract

The object of the invention are lubricating greases that contain calcium lignin sulfonates, and which consist of a base oil, calcium soaps, calcium lignin sulfonate having average molecular weights (weight average) greater than 10,000 g/mol as well as other, optional alkaline earth lignin sulfonates, producible by heating to temperatures above 120° C. converting and driving out components with low boiling point in order to produce a base grease, and cooling and addition of base oil and possibly other additives with mixing, a corresponding process, and use of the lubricating greases containing calcium lignin sulfonate.

1 . A process for producing lubricating greases containing lignin sulfonates comprising:
 mixing:
 at least one base oil 
 at least one calcium soap of a saturated or unsaturated monocarboxylic acid having 10 to 32 carbon atoms, optionally substituted, 
 at least one complexing agent selected from:
 (i) an alkali salt, with the exception of sodium salt, an alkaline earth salt or aluminium salt, of a saturated or unsaturated monocarboxylic acid or hydroxycarboxylic acids having 2 to 8, a dicarboxylic acid having 2 to 16 carbon atoms, each of which optionally substituted, 
 (ii) an alkali or alkaline earth salt of boric acid and/or phosphoric acid, including the reaction products thereof with LiOH and/or Ca(OH) 2 , and 
 (iii) mixtures thereof, and 
 
 at least calcium lignin sulfonate having average molecular weights (weight average) of greater than 10,000 g/mol, 
   heating to above 120° C. to initiate the reaction and drive out components   having low boiling point to produce a base grease, and b) cooling and adding the base oil and one or more additives during the mixing.   
     
     
         2 . The process according to  claim 1 , where calcium hydroxide is added optionally together with alkaline earth hydroxides during the mixing 
     
     
         3 . The process according to  claim 1 , where the lubricating grease is adjusted for alkalinity, by adding an excess quantity of calcium hydroxide. 
     
     
         4 . The process according to  claim 1 , where the heating takes place to temperatures higher than 180° C. 
     
     
         5 . The process according to  claim 1 , where, during the mixing, in addition to calcium hydroxide, lithium hydroxide, magnesium hydroxide and/or aluminium hydroxide and/or aluminium alcoholates and/or aluminium oxoalcoholates and/or lithium-, magnesium- and/or aluminium soaps of a saturated or unsaturated monocarboxylic acid having 10 to 32 carbon atoms, optionally substituted, are used. 
     
     
         6 . The process according to  claim 1 , where the lubricating grease contains, independently of each other:
 55 to 92 wt %, particularly 70 to 85 wt % base oil,   0 to 40 wt %, particularly 2 to 10 wt % additives,   3 to 40 wt %, particularly 5 to 20 wt %, calcium soaps, and   0.5 to 10 wt % complexing agents, and   optionally excess Ca(OH) 2 , preferably 0.01 to 2 wt %, and   0.5 to 15 wt %, and particularly preferably 4 to 8 wt % calcium lignin sulfonate, optionally in addition to other alkaline earth lignin sulfonates, relative in each case to the overall composition of the lubricating grease.   
     
     
         7 . The process according to  claim 1 , producing the base grease by using:
 40 to 70 wt %, particularly 45 to 60 wt % base oil,   10 to 60 wt %, particularly 15 to 50 wt %, calcium soaps, and   5 to 30 wt % complexing agent, and   optionally excess Ca(OH) 2 , preferably 0.02 to 4 wt %, and   0.7 to 30 wt % calcium lignin sulfonate, optionally in addition to other alkaline earth lignin sulfonates,   relative in each case to the composition of the base grease.   
     
     
         8 . The process according to  claim 1 , where the base grease contains, independently of each other, 0.2-5 wt % graphite and/or no solid lubricant or less than <1 wt % solid lubricant, particularly no MoS 2 . 
     
     
         9 . The process according to  claim 1 , where the calcium soap is produced in-situ as a by-product of reacting calcium hydroxide with a saturated or unsaturated monocarboxylic acid having 10 to 32 carbon atoms, particularly having 16 to 20 carbon atoms, optionally substituted by hydroxy, as an ester or anhydride. 
     
     
         10 . The process according to  claim 1 , where the complexing agent as a product of the reaction of a calcium salt, particularly calcium hydroxide, with a saturated or unsaturated monocarboxylic acid having 2 to 8, particularly 2 to 4, carbon atoms, or a dicarboxylic acid having 2 to 16, particularly 2 to 12 carbon atoms, each of which may or may not be substituted by hydroxyl as an ester or anhydride, is added during the mixing. 
     
     
         11 . The process according to  claim 1 , where the complexing agent is a calcium salt of a carboxylic acid and is produced in situ during the mixing by adding a saturated or unsaturated monocarboxylic acid having 2 to 8, particularly 2 to 4, carbon atoms or a dicarboxylic acid having 2 to 16, particularly 2 to 12 carbon atoms, each of which may or may not be substituted by hydroxyl as an ester or anhydride. 
     
     
         12 . The process according to  claim 1  where the calcium lignin sulfonate is dewatered to values less than 0.5 wt % water before it is added by heating in the base oil to above 95° C., particularly above 100° C. 
     
     
         13 . The process according to  claim 1  where the composition contains 0.5 to 20 wt %, particularly 0.5 to 10 wt % of the complexing agent 
     
     
         14 . A lubricating grease compound containing
 55 to 92 wt %, particularly 70 to 85 wt %, base oil,   0 to 40 wt %, particularly 2 to 10 wt %, additives,   3 to 40 wt % particularly 5 to 20 wt %, calcium soaps of a saturated or unsaturated monocarboxylic acid having 10 to 32 carbon atoms, optionally substituted,
 0.5 to 10 wt % complexing agent, selected from
 (i) an alkali salt, with the exception of sodium salt, an alkaline earth salt or aluminium salt, of a saturated or unsaturated monocarboxylic acid or hydroxycarboxylic acids having 2 to 8, a dicarboxylic acid having 2 to 16 carbon atoms, each of which is optionally substituted, 
 (ii) an alkali or alkaline earth salt of boric acid and/or phosphoric acid, including the products of reaction thereof with LiOH and/or Ca(OH) 2 , optionally excess Ca(OH) 2 , preferably 0.01 to 2 wt %, and 
 (iii) mixtures thereof, and 
 
   0.5 to 15 wt %, and 2 to 8 wt % calcium lignin sulfonate, in addition to other alkaline earth lignin sulfonates, relative in each case to the total composition of the lubricating grease,   wherein the compound comprises a cone penetration value (worked penetration) from 265 to 385 mm/10 (at 25° C.), determined according to ISO 2137.   
     
     
         15 . The composition according to  claim 14 , comprises comprising a cone penetration value (worked penetration) from 285 to 355 mm/10, determined according to ISO 2137. 
     
     
         16 . The composition according to  claim 14 , where the base oil has a kinematic viscosity from 20 to 2500 mm2/s, preferably from 40 to 500 mm2/s, at 40° C. 
     
     
         17 . The composition according to  claim 14 , where the complexing agent consists of:
 an alkali salt, preferably lithium salt, alkaline earth salt, preferably calcium salts, or aluminium salt of a saturated or unsaturated monocarboxylic acid having 2 to 8, particularly 2 to 4, carbon atoms or a dicarboxylic acid having 2 to 16, particularly 2 to 12, carbon atoms, each of which is optionally substituted.   
     
     
         18 . The composition according to  claim 14 , where the additive comprises one or more members selected from the following group:
 amine compounds, phenol compounds, sulfur antioxidants, zinc dithiocarbamate or zinc dithiophosphate as antioxidants;   organic chlorine compounds, sulfur, phosphorus or calcium borate, zinc dithiophosphate, organic bismuth compounds as high pressure additives;   C2- to C6- polyols, fatty acids, fatty acid esters or animal or vegetable oils;   petroleum sulfonate, dinonylnaphthalone sulfonate or sorbitan ester as anticorrosion agents;   benzotriazol or sodium nitrite as metal neutralisers;   polymethacrylate, polyisobutylene, oligo-dec- 1-enes and polystyrenes as viscosity enhancers;   molybdenum dialkyl dithiocarbamates or molybdenum sulfide dialkyl dithiocarbamates or aromatic amines as anti-wear additives;   functional polymers, comprising oleyl amides, polyether- and amide-based organic compounds, or molybdenum dithiocarbamate as friction modifiers, and polymer powders such as polyamides, polyimides or PTFE, graphite, metal oxides, boron nitride, metal sulfides such as molybdenum disulfide, tungsten disulfide or mixed sulfides with tungsten, molybdenum, bismuth, tin and zinc base, inorganic salts of alkaline and alkaline earth metals, such as calcium carbonate, sodium and calcium phosphates as solid lubricants.   
     
     
         19 . The composition according to  claim 14 , where the lubricating grease is water-resistant, particularly
 a) in accordance with the test defined in DIN 51807-1, evaluation level 1-90, and/or   b) in accordance with the test defined in DIN 51807-2 evaluation level 1-80.   
     
     
         20 . The composition according to  claim 14 , where the calcium lignin sulfonate has an average molecular weight (Mw, weight average) of more than 10,000, particularly more than 12,000, or even more than 15,000 g/mol, and independently thereof contains 2 to 12 wt %, particularly 4 to 10 wt %, sulfur (calculated as elemental sulfur) and/or also independently 5 to 15 wt %, particularly 8 to 15 wt % calcium. 
     
     
         21 . The composition according to  claim 14 , where the lubricating grease contains a base oil made on the basis of renewable raw materials and/or a fraction of 95% or more thereof is made on the basis of renewable raw materials. 
     
     
         22 . The composition according to  claim 14 , where the composition has a dropping point higher than 200° C. according to DIN ISO 2176. 
     
     
         23 . A method for lubricating at least a transmission using the composition according to  claim 14 . 
     
     
         24 . A method for lubricating lubrication points in constant velocity joints that have a joint shaft boot constructed from thermoplastic polyether esters as the joint shaft boot material using the composition according to  claims 14 .