Lubricating grease comprising metal soaps and metal complex soaps based on R-10-hydroxyoctadecanoic acid

Abstract

The invention relates to lubricating greases based on alkali metal soaps and/or earth-alkali metal soaps and metal complex soaps based on (R)-10-hydroxyoctadecanoic acid and to the use thereof.

Claims

1. A grease composition comprising: a) at least one base oil; b) at least one additive; c) at least one thickener, wherein said at least one thickener is a metal soap, or a metal complex soap or both composed of at least one alkali or alkaline earth metal ion or both and at least one carboxylate formed from a C16 to C18 fatty acid, wherein the C16 to C18 fatty acid comprises at least R-10-hydroxyoctadecanoic acid and the 10-hydroxyoctadecanoic acid has an enantiomeric purity with respect to the R-isomer of greater than 80 wt. %; wherein the C16 to C18 fatty acid consists of greater than 50 wt. % of 10-hydroxyoctadecanoic acid; and wherein the composition comprises: a) 55 to 98 wt. % of the base oil; b) 0.5 to 40 wt. % of the additive(s); and c1) 1.5 to 25 wt. % of metal soap; or c2) 1.5 to 40 wt. % of the metal complex soap comprising 0.1 to 20 wt. % of complexing agent.

2. The lubricating grease composition according to claim 1, wherein i) the C16 to C18 fatty acid consists of more than 80 wt. % of 10-hydroxyoctadeacanoic acid; or ii) the 10-hydroxyoctadecanoic acid has an enantiomeric purity with respect to the R-isomer of greater than 90 wt. %; or iii) both.

3. The lubricating grease composition according to claim 1, wherein the C16 to C18 fatty acid comprises greater than 0.5 wt. % hexadecanoic acid.

4. The lubricating grease composition according to claim 1, wherein the C16 to C18 fatty acid comprises greater than 0.2 wt. % hydroxyhexadecanoic acid.

5. The lubricating grease composition according to claim 1, wherein the C16 to C18 fatty acid comprises greater than 0.2 wt. % octadecanoic acid.

6. The lubricating grease composition according to claim 1, wherein the C16 to C18 fatty acid comprises octadecenoic acid.

7. The lubricating grease composition according to claim 1, wherein the C16 to C18 fatty acid comprises greater than 0.2 wt. % octadecadienoic acid.

8. The lubricating grease composition according to claim 1, wherein the C16 to C18 fatty acid comprises less than 1 wt % of 12-hydroxy-9-octadecenoic acid.

9. The lubricating grease composition according to claim 1, wherein the C16 to C18 fatty acid comprises less than 1 wt % of 12-hydroxyoctadecanoic acid.

10. The lubricating grease composition according to claim 1, wherein the C16 to C18 fatty acids contain hydroxy-substituted C16 to C18 fatty acids obtained from an enzymatic conversion of the corresponding unsaturated C16 to C18 fatty acid.

11. The lubricating grease composition according to claim 1, wherein the C16 to C18 fatty acids are obtained from edible fats or biodiesel, comprising at least one enzymatic conversion.

12. The composition according to claim 1, wherein the metal soap or metal complex soap is a lithium soap or lithium complex soap or a lithium/calcium soap or lithium/calcium complex soap.

13. The lubricating grease composition according to claim 1, wherein the complexing agent is selected from: alkali salts or alkaline earth salts or both of a) a saturated or unsaturated monocarboxylic acid or also hydroxycarboxylic acids having 2 to 8 carbon atoms, or of b) a di-carboxylic acid having 2 to 16 in each case optionally substituted, or alkali or alkaline earth salts of boric acid or phosphoric acid or both, or esters of boric acid or phosphoric acid or both with unbranched or branched alkyl groups having 2 to 32 carbon atoms, or mixtures thereof.

14. The composition according to claim 1, wherein the composition comprises: a) 70 to 95 wt. % of the base oil; b) 2 to 20 wt. % of the additive(s); and c1) 3 to 10 wt. % of metal soap; or c2) 1.5 to 40 wt. % of the metal complex soap comprising 0.1 to 10 wt. % of the complexing agent.

15. The lubricating grease composition according to claim 1, wherein the lubricating grease composition comprises a further metal soap or a further metal complex soap of saturated or unsaturated mono-carboxylic acids or also hydroxycarboxylic acids having 10 to 15 or 19 to 24 carbon atoms or both, including mixtures thereof.

16. The lubricating grease composition according to claim 1, wherein the lubricating grease composition further comprises co-thickeners selected from one or more members of the group: aluminosilicates, aluminas, hydrophobic and hydrophilic silicas, polymers, di/poly-ureas, di/poly-urea urethanes and PTFE.

17. The lubricating grease composition according to claim 1, wherein the lubricating grease composition has a cone penetration value (worked penetration) of 210 to 475 mm/10 at 25° C., determined according to ISO 2137.

18. The lubricating grease composition according to claim 1, wherein the base oil has, at 40° C., a kinematic viscosity of from 14 to 2500 mm.sup.2/s.

19. The lubricating grease composition according to claim 1, wherein the additive comprises one or more members selected from the following group: antioxidants; high-pressure additives; anti-corrosive agents; metal deactivators; viscosity improvers; wear protection additives; friction modifiers; and solid lubricants.

20. A method for preparing a lubricating grease composition according to claim 1 by bringing together a) at least one base oil; b) at least one additive; c) at least one thickener, wherein said at least one thickener is a metal soap or metal complex soap composed of alkali or alkaline earth metal ions and an R-10 hydroxyoctadecanoic acid, wherein said metal soap or metal complex soap is prepared in the base oil while being heated to at least 170° C. and said additive is added after cooling down to below 100° C.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) The composition according to the invention comprises at least: a) a base oil or a base oil mixture from 55 to 98 wt. % and in particular from 70 to 97 wt. %, preferred base oils being, e.g., polyalphaolefins, mineral oils and/or esters; b) additives from 0.5 to 40 wt. % and in particular from 2 to 20 wt. %, c) a thickener, wherein the thickener is or comprises a metal soap or a metal complex soap comprising a R-10 hydroxyoctadecanate metal soap, and the metal soap used according to the invention or the metal complex soap used according to the invention (then with complexing agent) is contained from 1.5 to 25 wt. %, preferably 3 to 10 wt. % (with respect to the metal soap) or from 1.5 to 40 wt. % with respect to the metal complex soap, comprising 0.1 to 20 wt. % of complexing agent, preferably comprising from 0.1 to 10 wt. % of complexing agent, and the metal soap salt used for production is a metal hydroxide of alkali and/or alkaline earth hydroxides (metal soaps used according to the invention).

(2) The specified wt. % refer to the total composition and each apply independently of each other.

(3) Standard lubricating oils that are liquid at room temperature are suitable as base oils. In particular, the base oil has a kinematic viscosity of 14 to 2500 mm.sup.2/s, preferably 30 to 500 mm.sup.2/s, in each case at 40° C.

(4) The base oils can be classified as mineral oils or synthetic oils. Mineral oils are considered to be naphthenic mineral oils and paraffinic mineral oils, according to API Group I classification. Chemically modified low-aromatic and low-sulphur mineral oils with a low content of saturated compounds and a viscosity/temperature behaviour that is improved as compared to Group I oils, classified according to API Group II III, Group III+ and synthetic oils produced from natural gas in the so-called gas-to-liquid process (GTL oils) are also suitable.

(5) Examples of synthetic oils are di- or polyethers, esters, polyalphaolefins, polyglycols and alkylaromatics and mixtures thereof. The di-ether compound can be a compound with aliphatic residues and/or aromatic residues (e.g., alkylated diphenyl ethers). The polyether compound may have free hydroxyl groups, but may also be fully etherified or end-group-esterified and/or made of a starting compound with one or more hydroxy and/or carboxyl groups (—COOH). Diphenyl ethers or polyphenyl ethers, alkylated if applicable, are also possible as sole components or, even better, as mixed components. Suitable esters are esters of an aromatic di-, tri- or tetracarboxylic acid with one of C2 to C30 alcohols or a mixture thereof, esters of adipic acid, sebacic acid, trimethylolpropane, neopentyl glycol, pentaerythritol or dipentaerythritol with aliphatic branched or unbranched, saturated or unsaturated C2 to C22 carboxylic acids, C18 dimeric acid esters with C2 to C22 alcohols, complex esters, as individual components or in any mixture desired.

(6) Particularly suitable base oils are or contain polyalphaolefins, e.g., those that are obtainable from polymerisation, if necessary using metallocene catalysts, C4 and C14 LAOs (LAO=linear alpha olefin), C6 and C16 LAOs; C8, C10 and C12 LAOs; C8 and C14 LAOs; C6, C10 and C14 LAOs; C4 and C12 LAOs as copolymers or as mixtures of the respective homopolymers.

(7) It has further been found that in contrast to conventional 12-hydroxyoctadecanate metal greases, lubricating greases based on metal R-10-hydroxyoctadecanate, especially in base oils containing or consisting of polyalphaolefins, exhibit an unexpected advantage in low-temperature behaviour and efficiency. In these properties, the soaps used according to the invention differ significantly from conventional 12-hydroxyoctadecanate soaps.

(8) Optionally, in addition to the C16 to C18 fatty acids as described above, other fatty acids can also be reacted with metal salts such as metal hydroxides to obtain further metal soaps. They may be alkali or alkaline earth salts of one or more saturated or unsaturated monocarboxylic acids having 10 to 15 and/or 19 to 24 carbon atoms, if necessary substituted like preferred corresponding hydroxycarboxylic acids. Suitable carboxylic acids are, for example, lauric acid, myristic acid or behenic acid. In addition to the unbranched-chain fatty acids mentioned, saturated or unsaturated branched-chain fatty acids can also be used. Naphthenic acids, neodecanoic acids or comparable neo acids can also be used.

(9) Simple, mixed or complex soaps based on Al-, Bi-, Ti-salts and carboxylic acids or on Li-, Na-, Mg-, Ca-, Al-, Bi-, Ti-salts and sulphonic acids can also be added as further metal soaps during the base fat production or later as an additive. Alternatively, these soaps can also be formed in situ during the production of the metal soaps used according to the invention.

(10) Instead of the fatty acids with free acid group, appropriate lower alcohol esters with saponification can also be used in the production of the respective metal soaps, e.g., appropriate triglycerides as well as the methyl, ethyl, propyl, isopropyl or sec-butyl acetates of the acid/hydroxy acid, in order to achieve a better dispersion.

(11) In the metal complex soap embodiment, complexing agents are used during production in addition to the metal soaps already described. Complexing agents within the meaning of the present invention are: (a) the alkali and/or alkaline earth salts of a saturated or unsaturated monocarboxylic acid or also hydroxycarboxylic acids having 2 to 8, in particular 2 to 4 carbon atoms, or alkali and/or alkaline earth salts of a di-carboxylic acid having 2 to 16, in particular 2 to 12 carbon atoms, in each case substituted if necessary, and/or (b) the alkali or alkaline earth salt of boric acid and/or phosphoric acid, in particular reaction products with LiOH. and/or Ca(OH).sub.2, or the reaction product of alkali or alkaline earth hydroxide, in particular LiOH and/or Ca(OH).sub.2 with esters of boric acid or phosphoric acid, and/or (c) esters of boric acid and phosphoric acid with unbranched or branched alkyl groups having 2 to 32 carbon atoms, preferably 8 to 32 carbon atoms.

(12) Preferably, the complexing agent is (a).

(13) Particularly suitable monocarboxylic acids are acetic acid and propionic acid. Also suitable are hydroxybenzoic acids such as para-hydroxybenzoic acid, salicylic acid, 2-hydroxy-4-hexylbenzoic acid, metahydroxybenzoic acid, 2,5-dihydroxybenzoic acid (gentisic acid), 2,6-dihydroxybenzoic acid (gamma-resorcylic acid) or 4-hydroxy-4-methoxybenzoic acid. Particularly suitable dicarboxylic acids are adipic acid (C.sub.6H.sub.10O.sub.4), sebacic acid (C.sub.10H.sub.18O.sub.4), azelaic acid (C.sub.9H.sub.16O.sub.4) and/or 3-tert.-butyladipic acid (C.sub.10H.sub.18O.sub.4).

(14) For example, metaborate, diborate, tetraborate or orthoborate, such as monolithium orthoborate, can be used as borate (b). Possible phosphates are alkali (preferably lithium) and alkaline earth (preferably calcium) dihydrogen phosphate-hydrogen phosphateor-pyrophosphate, or calcium or lithium hydroxyapatite. The esters of boric acid and phosphoric acid can be those with unbranched or branched alkyl groups having 2 to 32, preferably 8 to 32 carbon atoms.

(15) Optionally, bentonites, such as montmorillonite (the sodium ions of which may be replaced or partially replaced with organically modified ammonium ions, if necessary), aluminosilicates, aluminas, hydrophobic and hydrophilic silicas, oil-soluble polymers (e.g., polyolefins, poly(meth)acrylates, polyisobutylenes, polybutenes or polystyrene copolymers), polyurea or polyurea-polyurethane or PTFE can be used as co-thickeners. The bentonites, aluminosilicates, aluminas, silicas and/or oil-soluble polymers may be added to produce the base fat or added later as an additive in the second step.

(16) During or after the production of the metal or metal complex soaps, lignin derivatives can also be added as co-thickeners or as additives. Lignin derivatives are effective components in lubricating greases and can be used to improve wear protection properties and corrosion load properties.

(17) Therein, the lignin derivatives can represent multifunctional components. Due to their high number of polar groups and aromatic structures, their polymeric structure and low solubility in all types of lubricating oils, powdery lignins and/or lignosulfonates are also suitable as solid lubricants in lubricating greases and lubricating pastes. In addition, the phenolic hydroxyl groups contained in lignin and lignosulfonates provide an ageing-inhibiting effect. In the case of lignosulfonates, the sulphur content in lignosulfonates promotes the EP/AW effect in greases. Preferably, lignins and/or calcium and/or sodium lignosulfonate or mixtures thereof are used. However, kraft lignins, soda lignins or organosolv lignins can also be used. Also possible is the addition of bio-based oligomers or polymers as solid lubricants or co-thickeners such as triterpenes, cellulose or modified cellulose, chitin and/or chitosan.

(18) In particular, the thickener (metal soaps according to the invention, further metal soaps and co-thickeners) is used in such a way that the composition contains enough thickener to obtain a cone penetration value (worked penetration) of 210 to 475 mm/10 (at 25° C.), preferably 230 to 385 mm/10 (at 25° C.) (determined according to DIN ISO 2137 or ASTM D 0217-97).

(19) The compositions according to the invention may further contain additives as additional substances. Common additives in the sense of the invention are antioxidants, anti-wear agents, corrosion inhibitors, detergents, dyes, lubricity improvers, adhesion improvers, viscosity additives, friction modifiers, high-pressure additives and metal deactivators.

(20) Examples of these are: primary antioxidants such as amine compounds (e.g., alkylamines or 1-phenyl-aminonaphthalene), aromatic amines such as phenyl-naphthylamines or diphenylamines or polymeric hydroxyquinolines (e.g., TMQ), phenol compounds (e.g., 2.6-di-tert-butyl-4-methylphenol), zinc dithiocarbamate or zinc dithiophosphate; secondary antioxidants such as phosphites, e.g., tris(2,4-ditert-butylphenylphosphite) or bis(2,4-ditert-butylphenyl)-pentaerythritol diphosphite; high-pressure additives such as organic chlorine compounds, sulphur or organic sulphur compounds, phosphorus compounds, inorganic or organic boron compounds, zinc dithiophosphate, organic bismuth compounds; active ingredients that improve the “oiliness” such as C2 to C6 polyols, fatty acids, fatty acid esters or animal or vegetable oils; anti-corrosive agents such as petroleum sulfonate, dinonyl naphthalene sulfonate or sorbitan ester; disodium sebacate, neutral or overbased calcium sulfonates, magnesium sulfonates, sodium sulfonates, calcium and sodium naphthalene sulfonates, calcium salicylates, amine phosphates, succinates, metal deactivators such as benzotriazole or sodium nitrite; viscosity improvers such as polymethacrylate, polyisobutylene, oligo-dec-1-ene, polystyrenes; wear protection additives and friction modifiers such as organomolybdenum complexes (OMC), molybdenum-di-alkyl-dithiophosphates, molybdenum-di-alkyl-dithiocarbamates or molybdenum-di-alkyl-dithiocarbamates, in particular molybdenum-di-n-butyl-dithiocarbamate and molybdenum-di-alkyl-dithiocarbamate (Mo.sub.2mSn(dialkyl-carbamate).sub.2 with m=0 to 3 and n=4 to 1), zinc dithiocarbamate or zinc dithiophosphate; or a trinuclear molybdenum compound corresponding to the formula:
Mo.sub.3S.sub.kL.sub.nQ.sub.z wherein L are independently selected ligands having organo groups with carbon atoms as disclosed in U.S. Pat. No. 6,172,013 B1 to render the compound soluble or dispersible in the oil, wherein n ranges from 1 to 4, k ranges from 4 to 7, wherein Q is selected from the group of neutral electron donor compounds consisting of amines, alcohols, phosphines and ethers, and wherein z ranges from 0 to 5 and comprises non-stoichiometric values (see DE 102007048091); friction modifiers such as functional polymers, e.g., oleylamides, polyether and amide based organic compounds, e.g., alkyl polyethylene glycol tetradecylene glycol ether, polyisobutylene succinimide, polyisobutylene succinic imide (PIBSI) or polyisobutylene succinic anhydride (PIBSA). In addition, the lubricating grease compositions according to the invention contain customary additives against corrosion and oxidation and for protection against metal influences, which act as chelate compounds, radical scavengers, UV converters, reaction layer formers and the like. Additives that improve the hydrolysis resistance of ester base oils, such as carbodiimides or epoxides, can also be added. Solid lubricants that can be used are, e.g., polymer powders such as polyamides, polyimides or PTFE, melamine cyanurate, graphite, metal oxides, boron nitride, silicates, e.g., magnesium silicate hydrate (talcum), sodium tetraborate, potassium tetraborates, metal sulphides such as molybdenum disulphide, tungsten disulphide or mixed sulphides based on tungsten, molybdenum, bismuth, tin and zinc, inorganic salts of alkali and alkaline earth metals, such as calcium carbonate, sodium and calcium phosphates. Likewise carbon black or other carbon-based solid lubricants such as nanotubes can be used. Lignin derivatives can also be used as a thickener component or solid lubricant. Also possible are bio-based oligomers or polymers such as triterpenes, modified cellulose, chitin, chitosan or polypeptides.

(21) The lubricating greases according to the invention are particularly suitable for use in plain and roller bearings, gears and/or constant velocity joint shafts in industrial and automotive applications. It is a particular aspect of the present invention to arrive at low-friction lubricating greases, especially at low temperatures, where low breakaway torques and running torques are required and where a low flow point and shear viscosity are advantageous. In the particular case of lubrication of plain and roller bearings and gears and constant velocity joint shafts in automotive engineering, smaller and lighter drives can thus be used and efficiency advantages gained. Lubricating greases produced according to the present invention have, in particular at −35° C., up to 43% lower flow points (measured with the oscillation rheometer according to DIN 51810-2) and up to 50% lower shear viscosities (determined with the shear viscometer according to DIN 51810-1) than comparable lubricating greases. In the test of the flow pressure according to DIN 51805-2, the lubricating greases that are produced according to the present invention show, at −40° C., values which are at least 50% lower than comparable lubricating greases. Furthermore, the lubricating greases according to the invention have sliding friction coefficients in steel/steel contact that are up to 37% lower than those of a comparable lubricating grease based on 12-hydroxyoctadecanoic acid.

(22) Various laboratory test methods are available for testing the flow points and shear viscosity of lubricating greases. One method for determining the flow point using an oscillation rheometer is DIN 51810-2. The flow pressure method according to DIN 51805-2 is also used to determine the lower service temperature of lubricating greases. The flow pressure is the pressure difference from atmospheric pressure required to force a grease string out of a test nozzle under the conditions specified in this standard. It is a measure of the stiffness of a lubricating grease at the respective test temperature and can be used in addition to the test according to DIN 51810-2 as a measure of the flow point.

(23) IP 186 and ASTM D 1478 describe the determination of the starting and running torques of ball bearings. With these test methods, the functionality of lubricating greases can be tested at low temperatures, e.g., −40° C. or −73° C.

(24) Thus, these test methods are part of numerous specifications of the automotive and aerospace industry (civil and military aviation) as well as of user specifications. They have proven to be useful test methods over the years. DIN 51805-2, determination of flow pressure, is mainly used in Germany as a national method to determine the lower service temperature of lubricating greases.

(25) The lubricating greases can be produced, for example, as follows: mixing the salt/metal compound into the carboxylic acid compound, which may be stretched with the base oil component if necessary, plus the complexing agent if necessary, and, if necessary, simultaneously heating the mixture to a temperature above 100° C., in particular above 170° C., to form a thickened lubricating grease product; cooling the lubricating grease product and, if necessary, adding water; applying shear forces to the mixture, e.g., with a toothed colloid mill, a high-pressure homogeniser and/or a three-roller mill. According to a further embodiment of the invention, the thickener is synthesised in situ in the base oil under pressure and at elevated temperature in a closed reaction vessel, such as an autoclave.

(26) The lubricating grease composition can be used for lubricating gears, constant velocity joint shafts, plain and roller bearings, sliding guides, spindle drives, linear drives, ball screws, in particular with a lower operating temperature of less than −20° C., and/or in automobiles, aircraft, drones or helicopters. Other applications include the lubrication of steering systems, sunroofs, window lifters, side mirror adjusters, door locks, chassis wheel bearings, especially in automobiles, aircraft, drones or helicopters. The lubricating grease composition is also suitable for lubricating electric motor bearings, especially in hybrid vehicles or fully electric vehicles.

TRIAL EXAMPLES

Example A (Reference)

(27) Lithium-12-Hydroxyoctadecanoic Acid Fat with Polyalphaolefin

(28) 171 g of polyalphaolefin (mixture of PAO 6:PAO 150=3:1) and 45.25 g 12-hydroxyoctadecanoic acid as racemate were put into a stirred-tank reactor and heated to 86° C. Then 6.31 g of lithium hydroxide monohydrate was added, which was previously dissolved in 25 g of distilled water. Subsequently, the substances were heated to 210° C. and then cooled down to less than 100° C. over a period of 20 min, and the additives were added.

(29) The lubricating grease was then homogenised with a three-roller mill and adjusted to the desired consistency by gradually adding further polyalphaolefin. The lubricating grease thus produced had a thickener content of 12.13 wt. % and a worked penetration of 332 0.1 mm.

Examples B1, B2, B3 (Invention)

(30) Lithium-10-Hydroxyoctadecanoic Acid Fats with Polyalphaolefin

(31) 171 g of polyalphaolefin (mixture of PAO 6 (metallocene-based):PAO 150=3:1) and 35.16 g R-10-hydroxyoctadecanoic acid were put into a stirred-tank reactor and heated to 91° C. Then 5.07 g of lithium hydroxide monohydrate was added, which was previously dissolved in 21 g of distilled water. Subsequently, the substances were heated to 210° C. and then cooled down to less than 100° C. over a period of 20 min, and the additives were added. The lubricating grease was then homogenised with a three-roller mill and adjusted to the desired consistency by gradually adding further polyalphaolefin. The lubricating greases produced in this way had thickener contents of 4.64 wt. % (B1), 4.97 wt. % (B2) and 5.06 wt. % (B3) and worked penetrations of 339 0.1 mm (B1), 332 0.1 mm (B2) and 320 0.1 mm (B3).

Example C (Reference)

(32) Lithium-12-Hydroxyoctadecanoic Acid Complex Fat with Polyalphaolefin

(33) 171 g of polyalphaolefin (mixture of PAO 6:PAO 150=3:1) and 45.25 g 12-hydroxyoctadecanoic acid as racemate were put into a stirred-tank reactor and heated to 91° C. Then 6.31 g of lithium hydroxide monohydrate was added, which was previously dissolved in 25 g of distilled water. Subsequently, the substances were heated to 210° C. and then cooled down to less than 122° C. over a period of 15 min. Then 1.25 g of (tris(2-ethylhexyl)orthoborate was added and cooled down to less than 100° C., and the additives were added. The lubricating grease was then homogenised with a three-roller mill and adjusted to the desired consistency by gradually adding further polyalphaolefin. The grease thus produced had a thickener content of 10.52% and a worked penetration of 328 0.1 mm as well as a dropping point of >300° C.

Example D (Invention)

(34) Lithium R-10-Hydroxyoctadecanoic Acid Complex Fat with Polyalphaolefin

(35) 171 g of polyalphaolefin (mixture of PAO 6:PAO 150=3:1) and 35.16 g R-10-hydroxyoctadecanoic acid were put into a stirred-tank reactor and heated to 91° C.

(36) Then 5.07 g of lithium hydroxide monohydrate was added, which was previously dissolved in 21 g of distilled water. Subsequently, the substances were heated to 210° C. and then cooled down to less than 122° C. over a period of 15 min. Then 1.19 g of (tris(2-ethylhexyl)orthoborate was added and cooled down to <100° C., and the additives were added. The lubricating grease was then homogenised with a three-roller mill and adjusted to the desired consistency by gradually adding further polyalphaolefin. The grease thus produced had a thickener content of 4.68 wt. % and a worked penetration of 335 0.1 mm as well as a dropping point of 293° C.

Example E (Reference)

(37) Lithium-12-Hydroxyoctadecanoic Acid Fat with Mineral Oil

(38) 107.48 g of mineral oil, Group II (kinematic viscosity=110 mm.sup.2/s at 40° C.) and 22.08 g of 12-hydroxyoctadecanoic acid (racemate) were put into a stirred-tank reactor and heated to 91° C. Then 3.18 g of lithium hydroxide monohydrate was added, which was previously dissolved in 15 g of distilled water. Subsequently, the substances were heated to 210° C. and then cooled down to <100° C. over a period of 20 min, and the additives were added. The lubricating grease was then homogenised with a three-roller mill and adjusted to the desired consistency by gradually adding further mineral oil, Group II SN 600. The lubricating grease thus produced had a thickener content of 8.3% and a worked penetration of 317 0.1 mm.

Example F (Invention)

(39) Lithium-10-Hydroxyoctadecanoic Acid Fat with Mineral Oil

(40) 107.12 g of mineral oil, Group II (kinematic viscosity=110 mm.sup.2/s at 40° C.) and 22.04 g of R-10-hydroxyoctadecanoic acid were put into a stirred-tank reactor and heated to 91° C. Then 3.17 g of lithium hydroxide monohydrate was added, which was previously dissolved in 15 g of distilled water. Subsequently, the substances were heated to 210° C. and then cooled down to less than 100° C. over a period of 20 min, and the additives were added. The lubricating grease was then homogenised with a three-roller mill and adjusted to the desired consistency by gradually adding further mineral oil, Group II SN 600. The lubricating grease thus produced had a thickener content of 4.21 wt. % and a worked penetration of 328 0.1 mm.

Example G (Reference)

(41) Lithium-12-Hydroxyoctadecanoic Acid Fat with Ester Oil

(42) 107.48 g of pentaerythritol ester (with a viscosity of 96 mm.sup.2/s at 40° C.) and 22.08 g of 12-hydroxyoctadecanoic acid were put into a stirred-tank reactor and heated to 91° C.

(43) Then 3.18 g of lithium hydroxide monohydrate was added, which was previously dissolved in 15 g of distilled water. Subsequently, the substances were heated to 210° C. and then cooled down to less than 100° C. over a period of 20 min, and the additives were added. The lubricating grease was then homogenised with a three-roller mill and adjusted to the desired consistency by gradually adding further pentaerythritol ester. The lubricating grease thus produced had a thickener content of 6.13% and a worked penetration of 328 0.1 mm.

Example H (Invention)

(44) Lithium R-10-Hydroxyoctadecanoic Acid Fat with Ester Oil

(45) 107.12 g of pentaerythritol ester (with a viscosity of 96 mm.sup.2/s at 40° C.) and 22.04 g of 12-hydroxyoctadecanoic acid were put into a stirred-tank reactor and heated to 91° C. Then 3.17 g of lithium hydroxide monohydrate was added, which was previously dissolved in 15 g of distilled water. Subsequently, the substances were heated to 210° C. and then cooled down to less than 100° C. over a period of 20 min, and the additives were added. The lubricating grease was then homogenised with a three-roller mill and adjusted to the desired consistency by gradually adding further pentaerythritol ester. The lubricating grease thus produced had a thickener content of 4.08 wt. % and a worked penetration of 335 0.1 mm.

(46) In the same base oil and additive matrix, the lubricating greases according to the invention produced with R-10-hydroxyoctadecanoic acid showed a thickening effect that was up to 62% better than that of a 12-hydroxyoctadecanoic acid.

Table of Examples

(47) TABLE-US-00001 A B1 B2 B3 C D Reference Invention Invention Invention Reference Invention Normal Normal Normal Normal Complex Complex soap soap soap soap soap soap PAO PAO PAO PAO PAO PAO Base oils Mineral oil, Group II (kinematic viscosity = 110 mm2/s at 40° C.) Polyalphaolefin, 75 cSt 76.12 83.61 83.28 83.19 77.73 82.96 (mixture PAO6: PAO150, 3:1) Pentaerythritol ester Fatty acids 10-hydroxyoctadecanoic acid type 1.sup.*1) 4.05 4.23 10-hydroxyoctadecanoic acid type 2.sup.*2) 4.34 10-hydroxyoctadecanoic acid type 3.sup.*3) 4.42 12-hydroxyoctadecanoic acid 10.65 8.76 Complexing agent Tris(2-ethylhexyl)orthoborate 0.49 0.45 Alkali hydroxide Lithium hydroxide monohydrate 1.48 0.59 0.63 0.64 1.27 0.61 Additives Aminic antioxidant 2.00 2.00 2.00 2.00 2.00 2.00 (alkylated diphenylamine) Phenolic antioxidants 0.50 0.50 0.50 0.50 0.50 0.50 (sterically hindered phenol) Secondary antioxidant 0.50 0.50 0.50 0.50 0.50 0.50 (alkyl phosphite) Wear protection additives.sup.*4) 7.25 7.25 7.25 7.25 7.25 7.25 Corrosion protection additive 1.50 1.50 1.50 1.50 1.50 1.50 (zinc carboxylate) .sup.*1)Purity >99% of R-10-hydroxyoctadecanoic acid .sup.*2)Purity 91.5% of R-10-hydroxyoctadecanoic acid, 8.5% of octadecanoic acid .sup.*3)Purity 91.5% of R-10-hydroxyoctadecanoic acid, 8.5% of octadecenoic acid .sup.*4)Contains organic compounds based on N, P, S, Zn and Mo

(48) TABLE-US-00002 E F G H Reference Invention Reference Invention Normal soap Normal soap Normal soap Normal soap Mineral oil Mineral oil Ester oil Ester oil Base oils Mineral oil, Group II (kinematic 79.95 84.04 viscosity = 110 mm.sup.2/s at 40° C.) Polyalphaolefin, 75 cSt (mixture PAO6:PAO150, 3:1) Pentaerythritol ester 82.09 84.17 Fatty acids 10-hydroxyoctadecanoic acid type 1*.sup.1) 3.68 3.57 10-hydroxyoctadecanoic acid type 2*.sup.2) 10-hydroxyoctadecanoic acid type 3*.sup.3) 12-hydroxyoctadecanoic acid 7.25 5.36 Complexing agent Tris(2-ethylhexyl)orthoborate Alkali hydroxide Lithium hydroxide monohydrate 1.05 0.53 0.77 0.51 Additives Aminic antioxidant 2.00 2.00 2.00 2.00 (alkylated diphenylamine) Phenolic antioxidants 0.50 0.50 0.50 0.50 (sterically hindered phenol) Secondary antioxidant 0.50 0.50 0.53 0.50 (alkyl phosphite) Wear protection additives*.sup.4) 7.25 7.25 7.25 7.25 Corrosion protection additive 1.50 1.50 1.50 1.50 (zinc carboxylate) *.sup.1)Purity >99% of R-10-hydroxyoctadecanoic acid *.sup.2)Purity 91.5% of R-10-hydroxyoctadecanoic acid, 8.5% of octadecanoic acid *.sup.3)Purity 91.5% of R-10-hydroxyoctadecanoic acid, 8.5% of octadecenoic acid *.sup.4)Contains organic compounds based on N, P, S, Zn and Mo

(49) TABLE-US-00003 A B1 B2 B3 C Reference Invention Invention Invention Reference Normal Normal Normal Normal Complex soap soap soap soap soap Characteristic Polyalpha- Polyalpha- Polyalpha- Poyalpha- Polyalpha- values Unit Method olefin olefin olefin olefin olefin Thickener content % Calculation.sup.*5) 12.13 4.64 4.97 5.06 10.52 Delta LiOH × H2O % −60.14 −57.43 −56.76 addition amount (invention in relation to reference) Delta thickener (invention % −61.75 −59.03 −58.29 in relation to reference) Consistency class 0.1 mm NLGI 1 NLGI 1 NLGI 1 NLGI 1 NLGI 1 Worked penetration Pw 60 DIN ISO 2137 332 339 332 320 328 Dropping point according ° C. IP 396 210 193 198 205 300 to IP 396 Flow pressure at −40° C. hPa DIN 51805 250 125 200 Delta flow pressure % −50.00 (invention in relation to reference) Shear viscosity Pa s DIN 51810-1 60.4 31.7 at −35° C, eta E Delta shear viscosity % −47.52 (invention in relation to reference) Flow point at −35° C. Pa DIN 51810-2 752 425.4 Delta flow point (invention % −43.43 in relation to reference) Sliding friction coefficient % See 0.102 0.083 0.108 μ at 60° C. description.sup.*6) Delta friction value % −18.31 (invention in relation to reference) .sup.*5)Sum of the added amount of LiOH monohydrate + fatty acid + complexing agent .sup.*6)12.7-mm ball on 3 surfaces (material 100Cr6), surface pressure in point contact 144 N/mm2, sliding speed 0.057 m/s

(50) TABLE-US-00004 D E F G H Invention Reference Invention Reference Invention Complex Normal Normal Normal Normal soap soap soap soap soap Polyalpha- Mineral Mineral Ester Ester Characteristic values Unit Method olefin oil oil oil oil Thickener content % Calculation.sup.*5) 4.68 8.30 4.21 6.13 4.08 Delta LiOH × H2O % −51.97 −49.52 −33.77 addition amount (invention in relation to reference) Delta thickener (invention % −55.51 −49.28 −33.44 in relation to reference) Consistency class 0.1 mm NLGI 1 NLGI 1 NLGI 1 NLGI 1 NLGI 1 Worked penetration Pw 60 DIN ISO 2137 335 317 328 328 335 Dropping point according C. IP 396 293 227 191 202 186 to IP 396 Flow pressure at −40° C. hPa DIN 51805 150 1350 950 675 525 Delta flow pressure % −25.00 −29.63 −22.22 (invention in relation to reference) Shear viscosity Pa s DIN51810-1 at −35° C., eta E Delta shear viscosity % (invention in relation to reference) Flow point at −35° C. Pa DIN 51810-2 Delta flow point (invention % in relation to reference) Sliding friction coefficient See 0.082 0.107 0.068 0.120 0.079 μ at 60° C. description.sup.*6) Delta friction value (invention in relation to % −23.77 −37.06 −33.97 reference) .sup.*5)Sum of the added amount of LiOH monohydrate + fatty acid + complexing agent .sup.*6)12.7-mm ball on 3 surfaces (material 100Cr6), surface pressure in point contact 144 N/mm2, sliding speed 0.057 m/s