United States Patent (19) 11 3,929,651 Murray et al. (45) Dec. 30, 1975

54 MODIFIED LITHIUM SOAP GREASE Primary Examiner-Delbert E. Gantz Assistant Examiner-I. Vaughn 75 Inventors: Donald W. Murray, Sarnia; Warren Attorney, Agent, or Firm-Byron O. Dimmick C. Pattenden, Mooretown, both of Canada (57) ABSTRACT 73 Assignee: Exxon Research & Engineering Co., A grease composition that combines good water resis Linden, N.J. tance, good mechanical stability and high oil retention (22 Filed: Sept. 25, 1974 with excellent oxidation stability and high dropping point is prepared by the use of a novel thickener sys (21) Appl. No.: 509,231 tem whose essential components include a combina Related U.S. Application Data tion of dilithium salt of a C-C dicarboxylic acid, e.g. 63 Continuation of Ser. No. 90,877, Nov. 18, 1970, dilithium azelate; a lithium soap of a 9-, 10-, or 12 abandoned. hydroxy C to C fatty acid, e.g. lithium 12-hydroxy stearate; and a lithium salt formed in situ in the grease 52 U.S. Cl...... 252/41 from a second hydroxy carboxylic acid wherein the 51) Int. Cl.". C10M 1/24; C10M 3/18; C10M 5/14; OH group is attached to a carbon atom not more than ClOM 7/20 6 carbon atoms removed from the carboxyl group, and 58 Field of Search...... 252/41 wherein either of those groups may be attached to ei ther aliphatic or aromatic portions of a molecule. If 56 References Cited desired, sufficient lithium hydroxide can be added to UNITED STATES PATENTS form the dilithium salt of the latter acid through reac 2,951,808 9/1960 Norton et al...... 252/41 tion of its hydroxyl group. 3,223,624 12/1965 Morway et al...... 252/4 3,223,633 12/1965 Morway et al...... 252/41 8 Claims, No Drawings 3,711 .407 l/1973 Plumstead...... 252/41 3,929,651 1. 2 tendency of such greases to undergo surface hardening MODIFIED LITHIUM SOAP GREASE on standing. The hydroxy fatty acid employed in preparing the BACKGROUND OF THE INVENTION greases of this invention will have from about 12 to 24, This is a continuation of application Ser. No. 90,877, or more usually about 16 to 20 carbon atoms, and still filed Nov. 18, 1970 and now abandoned. preferably be a hydroxy-stearic acid, e.g. 9-hydroxy, This invention concerns a modified lithium soap 10-hydroxy, or 12-hydroxystearic acid, more prefera grease of premium quality with outstanding properties bly the latter. Ricinoleic acid, which is an unsaturated which include a high dropping point, excellent oxida form of 12-hydroxystearic acid, having a double bond tion stability, long lubrication life and water resistance. 10 in the 9-10 position, can also be used. Lithium greases have been known and widely used The dicarboxylic acid used in the greases of this in for many years. The lithium soaps that are used as the vention will have from 4 to 12 carbon atoms, preferably thickening agents for these greases are ordinarily pre 6 to 10 carbon atoms. Such acids include succinic, pared by reaction of lithium hydroxide or other suitable glutaric, adipic, suberic, pimelic, azelaic, dodecanedi lithium base with a conventional high molecular weight 15 oic, and sebacic acids. Sebacic acid and azelaic acid are acid or acids. The principal advantages of lithium preferred. greases have been high water resistance and ease of The hydroxy carboxylic acid forming the third acid dispersion of the soaps in all types of lubricating oil component of the grease of this invention is one having base stocks. Particularly useful have been greases pre an OH group attached to a carbon atom that is not pared from lithium hydroxystearate, since the soaps of 20 more than 6 carbon atoms removed from the carboxyl the hydroxystearic acids and related hydroxy fatty group. This acid has from 3 to 14 carbon atoms and can acids have been found to be more mechanically stable be either an aliphatic acid such as lactic acid, 6 than the corresponding soaps of the conventional fatty hydroxy decanoic acid, 3-hydroxybutanoic acid, 4 acids. hydroxybutanoic acid, etc. or an aromatic acid such as There are many fields of application of grease com 25 parahydroxybenzoic acid, salicylic acid, 2-hydroxy-4- positions where a high dropping point is required, as for hexylbenzoic acid, meta hydroxybenzoic acid, 2,5- example in the lubrication of traction motor bearings. dihydroxybenzoic acid (gentisic acid); 2,6-dihydrox Such traction motors are used to propel modern diesel ybenzoic acid (gamma resorcylic acid), 4-hydroxy-3- locomotives. The engines of the diesel locomotives methoxybenzoic acid, etc. or a hydroxyaromatic ali generate direct current which is then used to run trac 30 phatic acid such as orthohydroxyphenyl, metahydrox tion motors which are geared directly to the driving yphenyl, or parahydroxyphenyl acetic acid. A cycloali axle and wheel assemblies in each truck of the locomo phatic hydroxy acid such as hydroxy cyclopentyl car tive. A single traction motor may contribute 200 horse boxylic acid or hydroxynaphthenic acid could also be power, and constitute 1/10 or more of the total motor used. power of the locomotive. The bearings of these loco 35 In place of the free hydroxy acid of the latter type motives may be required to operate for periods of as when preparing the grease, one can use a lower alcohol much as three years without any maintenance, and ester, e.g. the methyl, ethyl, or propyl, isopropyl or temperatures as high as 250F. can be reached in such sec-butyl ester of the acid, e.g. methyl salicylate, to give bearings. a better dispersion when the salt is insoluble. The 40 amount of dilithium salt of the hydroxy acid will range DESCRIPTION OF THE INVENTION from about 0.1 to about 10 wt.% of the finished grease, In accordance with the present invention, a lithium or preferably from about 0.5 to about 5 wt.%. base grease having excellent oxidation and mechanical The total soap and salt content of the grease will be stability and a dropping point of 500F. or higher is in the range of from about 2 to 30 weight percent and prepared from a 9-hydroxy, 10-hydroxy, or 12-hydroxy 45 preferably about 5 to 20 weight %. The proportion of C1 to C2, preferably Cie to Cao, fatty acid, a C to C12 the C to Ca hydroxy fatty acid to the dicarboxylic dicarboxylic acid, and a second hydroxy carboxylic acid will be in the range of 0.5 to 15 parts by weight of acid of from 3 to 14 carbon atoms, wherein the hydroxy the former to one part by weight of the latter, and group is attached not more than 6 carbon atoms re preferably in the range of 1.5 to 5 parts by weight of the moved from the carboxyl group. 50 hydroxy fatty acid to one part by weight of the dicar It has already been taught in U.S. Pat. No. 2,940,930 boxylic acid. The proportion of the second hydroxycar that high dropping point greases (500F. or greater) boxylic acid to the dicarboxylic acid will be from about can be prepared from mixtures of monocarboxylic and 0.025 to 2.5 parts by weight of the former to one part dicarboxylic acids. However, in preparing the greases by weight of the latter, preferably 0.125 to 1.25 parts described in that patent, it was necessary to also in 55 by weight of the former per part by weight of the latter. clude a glycol. The presence of a glycol is undesirable The lubricating oil base that is used in preparing the because it renders the grease prone to oxidation and grease compositions of this invention can be any of the makes the water resistance of the grease undesirably conventionally used mineral oils, synthetic hydrocar low in some applications. The present invention makes bon oils, or synthetic ester oils, and will generally have possible the preparation of high dropping point greases 60 a viscosity within the range of about 35 to 200 SUS at from a combination of hydroxy fatty acid and dicarbox 210°F. Synthetic lubricating oils that can be used in ylic aliphatic acid without the necessity of incorporat clude esters of dibasic acids such as di-2-ethylhexyl ing a glycol. sebacate, esters of glycols such as the Cia Oxo acid While U.S. Pat. Nos. 3,223,633 and 3,223,624 teach diester of tetraethylene glycol, or complex esters such the preparation of high dropping point greases from a 65 as a complex ester formed by reacting one mole of 3-component mixture of acids, the presence of a C, to sebacic acid with two moles of tetraethylene glycol and C fatty acid salt, which is an essential component of two moles of 2-ethylhexanoic acid. Other synthetic oils those greases, is frequently undesirable because of the that can be used include synthetic hydrocarbons such

H 3,929,651 3 4 as alkylbenzenes, e.g. alkylate bottoms from the alky TABLE I-continued lation of benzene with tetrapropylene, or the copoly Weight (1b) per 100 lb mers of ethylene and propylene; silicone oils, e.g. ethyl Ingredient Finished Base Grease phenyl polysiloxanes, methyl polysiloxanes, etc.; poly 104.500 glycol oils, e.g. those obtained by condensing butyl "Mixture of solvent refined and dewaxed paraffinic distiliates, hydrofinished, alcohol with propylene oxide; carbonate esters, e.g. the having a viscosity of 520 SUS at 100°F. and a V.I. of 93. product of reacting Cs Oxo alcohol with ethyl carbon '4.50 lb of water and methanol are formed through reaction of the base with the fatty acids and methyl salicylate. These are lost during the dehydration cycle, ate to form a half ester followed by reaction on the leaving a net yield of 100 lb of finished base grease. latter with tetraethylene glycol, etc. Other suitable 10 “This portion of the LiOH.HO required to neutralize the 12-hydroxystearic and synthetic oils include the polyphenyl ethers, e.g. those azelaic acids only. having from about 3 to 7 ether linkages and about 4 to “This portion of the LiOH.H.O required to react with the methyl salicylate to 8 phenyl groups. (See U.S. Pat. No. 3,424,678, column produce dilithium salicylate. The 12-hydroxystearic acid and the azelaic acid were The greases of this invention can be formed in a 15 charged to the kettle with about 55, weight % of the number of different ways. One convenient way when base oil, and the mixture was heated at 195-200F. the third acid is salicylic acid is to co-neutralize the until the carboxylic acids had dissolved. Then while the hydroxy fatty acid and the dicarboxylic acid in at least kettle temperature was maintained at 200 to 205°F., a a portion of the oil with lithium hydroxide. This neu hot saturated aqueous solution containing sufficient tralization will take place at a temperature in the range 20 lithium hydroxide to react with the hydroxystearic acid of about 180° to 220°F. When the soap stock has thick and the azelaic acid was added gradually over a period ened to a heavy consistency, the temperature is raised of one hour. When the soap stock had thickened to a to about 260' to 300°F. to bring about dehydration. heavy consistency, the temperature was raised to about The soap stock is then cooled to about 190° to 210°F. 270°F. as quickly as the dehydration process would and the ester of salicylic acid is added; then, additional 25 permit. When dehydration was essentially complete, as lithium hydroxide is added gradually to convert the indicated by a rapid increase in temperature to 300°F., salicylate ester to the dilithium salicylate salt. Reaction the soap stock was cooled to 200°F. by circulating cold is conducted at about 220 to 240°F., preferably with water through the jacket of the kettle; then the methyl agitation so as to facilitate the reaction. In this reaction, salicylate was added and mixed with the soap stock at the alcohol is evolved, and dilithium salicylate forms. 200F. Following this the remainder of the lithium Dehydration is then completed at 300 to 320°F. after hydroxide monohydrate (1.55 lbs per 100 lbs of the which the grease is heated at 380-390 F. for 15 min finished grease) was added very gradually as a hot utes to improve its yield and is then cooled while addi saturated solution. At this stage the heat input and tional oil is added to obtain the desired consistency. mixing rate were increased to speed up the dehydration Alternatively, the additional oil can be added to the 35 process (conducted at 212-275F.) and to avoid ac soap concentrate prior to the in situ formation in the cumulation of free water in the kettle. When all of the dilithium salicylate. lithium hydroxide solution had been added and dehy An alternative method is to co-neutralize all three dration was complete as noted by a rapid increase in types of acid used in making the grease, or to saponify 40 temperature, the entire mass of grease was heated to a a lower ester of the second type of hydroxy acid, e.g. temperature of 385F. and maintained there for 15 methyl salicylate, simultaneously with the neutraliza minutes to improve the grease structure. The grease tion of the hydroxyacid of the first type, e.g. hydroxy mixture was then rapidly cooled to about 300°F. by stearic acid and the dicarboxylic acid. Still another circulating cold water through the jacket of the kettle alternative is to co-neutralize the hydroxy fatty acid 45 and while adding a small amount of oil. After the tem and the ester of the second hydroxy acid followed by perature had been reduced to less than 300°F., the neutralization of the dicarboxylic acid. remaining oil was blended into the grease while it The following examples, which include a preferred cooled gradually. After the base grease had been embodiment, are presented to illustrate the preparation cooled to a temperature of between 150 and 200°F. it and various characteristics of greases manufactured was passed through a 100 mesh screen to complete its according to this invention. Comparative examples are 50 preparation. The product was a smooth uniform grease, also included to show that adverse or inferior results beige in color, with an unworked penetration of 230 at are obtained if components outside the scope of the 77°F. The worked penetration of this base grease at invention are used. 77F. was 230 after 60 strokes, 240 after 10,000 EXAMPLE I 55 strokes and 251 after 100,000 strokes. This example illustrates the preparation of a grease of EXAMPLE 2 this invention on a plant scale in a 1000 lb. kettle. The To prepare a grease suitable for lubrication of loco ingredients used and their proportions are given in the motive traction motor bearing the base grease of Exam following Table I. 60 ple 1 was modified by adding thereto by simple mixing 0.5 wt.% of phenyl alpha-naphthylamine to serve as an TABLE I oxidation inhibitor, 3.5 wt.% of the base oil described Weight (1b) per 100 lb in Table I, and 1.75% of a rust inhibitor concentrate Ingredient Finished Base Grease identified as Na Sul BSN, which consisted of 50 wt.% 12-Hydroxystearic Acid 11.50 65 Azelaic Acid 3.97 of a light mineral lubricating oil and 50 wt.% of a Lithium Hydroxide Monohydrate' 3.34 neutral barium dinonyl naphthalene sulfonate. Methyl Salicylate, USP 2.85 The properties of this grease are compared in Table Lithium Hydroxide Monohydrate' st; Lubricating Oil" II with a conventional lithium hydroxystearate grease 3,929,651 5 6 and with a lithium hydroxystearate grease, containing lower viscosity oil (90 V.I., 200 SUS at 100F.) with a dilithium salicylate, identified as DLS grease. The con calcium-lithium 12-hydroxy stearate soap mixture. The ventional lithium hydroxystearate grease was a com comparison is shown in Table IV. Taking into account mercial product containing lithium 12-hydroxystearate the viscosity of the oil used, the grease of Example 3 is as the only thickener. The grease DLS also had lithium 5 considered to have excellent torque properties. 12-hydroxystearate as the only thickener but it addi tionally-- contained 3 weight- percent of finely ground TABLE IV preformed dilithium salicylate powder as an antioxi- ASTM D1478 TORQUE dant. See U.S. Pat. No. 2,951,808. """" starting Running These three greases are compared in Table II, which 10 Example 3 Grease 8300 2360 follows. Commercial Ca-Li Grease 10,400 3000 TABLE I COMPARISON OF PROPERTIES OF GREASES Conventional Example 2 Lithium Hydroxy Product stearate Grease DLS Grease Oil Content, Wt.% 80.1 86 82. Oil Viscosity, SUS at 100°F. 520 485 520 ASTM Worked Penetration, 77°F., 60Strokes 248 253 234 5,000 strokes 265 250 10,000 Strokes 265 250 100,000 Strokes 277 264 304 ASTM Roller, 100 Hr. at 160 rpm A ASTM Pen. (77°F.)|Adhesion: 77OF. --28/OK -38/OK --12OFOK 150°F. --58/OK Water Absorption in ASTM Roller % HO AbsorbedIA ASTM Pen. (77°F.)/Adhesion: 77°F. 54f-2fOK -- 667-1081OK 50°F. 58.f44f OK 67f761OK 361-92fOK ASTM Dropping Point, F. 500 394 370 * ASTM Wheel Bearing, 6 Hr. at 200°F. Leakage, g/Slump 1.1 Nil 0.7/Nil 0.9/Nil Oil Separation, 30 Hr. at 212°F., Wt.% 1.9 1.1 3.9 NLGT Spindle Life, 10,000 rpm, 300°F., Hr. 2.388 288 1,566 ASTM Bomb Oxidation, 210F. Pressure Loss, psig, after: 100 Hr. 1.5 50 2.5 500 Hr. 50 10.0 11.5 ASTM D 1743 Rust Test Pass Fail Copper Corrosion Test, 24 Hr. at 22°F. Pass Fail Pass ASTM - 1263-53

It is to be noted that the grease of Example 2 had a dropping point of over 500F. as compared with 394°F. for the conventional lithium hydroxystearate grease EXAMPLE 4 and 370°F. for the grease into which powdered dili thium salicylate had been incorporated. 40 (Base Grease Preparation) This example describes the preparation of a base EXAMPLE 3 grease using a mole ratio of 1 mole of hydroxystearic Using the procedure of Examples 1 and 2, a grease acid, and 0.75 mole of azelaic acid, first forming a soap similar to that of Example 2, but using a lower viscosity concentrate and then a grease. Into 300 grams of 90 oil (250 SUS at 100°F. and 90 V.I.) was prepared. The 45 V.I. mineral lubricating oil having a viscosity at 100°F. composition of this grease, on the basis of weight per of 550 SUS there were dispersed 92 grams of 12 hydrostearic acid and 43.2 grams of azelaic acid at a cent of reactants, is given in Table III. temperature of 200F. Then 31.7 grams of lithium hy TABLE I droxide hydrate (LiOH.HO) was added and the reac Wt. 50 tion was continued at 200-240°F., after which the Mineral Oil, 90 V.I., 250 SUS at 100°F. 81.0 reaction product was dehydrated by heating it to 12-Hydroxystearic acid 8.77 Azelaic acid 2.67 300F. The free alkali content of the dehydrated prod Methyl salicylate .09 uct was 0.18%, which indicated that neutralization of Lithium hydroxide monohydrate 3.21 NaSul BSN (rust inhibitor) .75 all of the carboxyl groups was essentially complete. The Phenyl al-naphthylamine (oxidation) 55 temperature of the dehydrated product was raised to inhibitor) 0.50 390-400°F. for 30 minutes in order to improve the Pour depressant' 1.00 dispersion. The soap concentrate product was then "Oil concentrate, 20% active ingredient, of 2 parts wax-alkylated naphthalene and cooled while additional oil was added to give the de part C-C alkyl methacrylate polymer. sired consistency. This product is identified as a base 60 grease in the accompanying Table V. This grease had a dropping point of more than 600°F., and a worked penetration of 283 at 77°F. after EXAMPLE 5 60 strokes. It had an operating range of -40°F. to To make a grease of the present invention the same +400°F. and successfully passed the copper corrosion procedure was followed as for the soap concentrate of test (24 hours at 212°F.) and the ASTM D-1743 rust 65 Example 4. After the soap concentrate had been heat test. The starting and running torque values of this treated at 390-400F., 30.4 grams of methyl salicylate grease at -40°F. compared very favorably with those of and 17 grams of lithium hydroxide monohydrate were a commercial grease which had been prepared from a added at 220F. and the reaction was continued for 1 3,929,651 8 7 except that the dilithium salicylate was added to the hour at this temperature. In this reaction methyl alco base grease as a fine preformed powder (all particles hol was evolved and dilithium salicylate was formed in less than 150 microns in size) rather than being formed the concentrate. After dehydration had been con in situ in the grease. The resulting comparative grease ducted at 300°F. the grease was cooled and oil was was of substantially the same consistency as Grease D added to obtain the desired consistency. The grease is (ASTM penetration 300) but it had a dropping point of identified in the accompanying Table V as Grease A. . only 374°F and had a life of only 175 hours in the Static EXAMPLE 6 Oxidation Test.

- TABLE V PROPERTIES OF LITHIUM HYDROXYSTEARATE-DILITHIUMAZELATE GREASES GREASE Composition, Parts by Weight Base Grease A D E Lithium 12-hydroxystearate 93.6 93.6 93.6 102.0 Dilithium Azelate 45.9 45.9 45.9 - Mineral Oil, 90 V.I., 550 SUS at 100°F. 917.0 830.5 917.0 885.0 Dilithium Salicylate (3%), made in situ - 30.0 32.7 31.0 via methyl salicylate 1056.5 1000.0 1089.2 1018.0 DLS Particle Size None Fine Fine Coarse ASTM Penetration, 77°F., mm/10: 60 Strokes 291 305 304 248 100,000 Strokes - 335 m - ASTM Dropping Point, F. 390 525 500- 385 Static Oxidation Test, 350'F., hours to 80 280 295 35% weight loss Water Resistance in ASTM Roller, 150F. - 78F-32 m m % HO Absorbed/ASTM Penetration Change, 77°F. Oil Separation, Federal Test method, 30 hr. - 2.7 m m 212°F., Wt. % ASTM Wheel Bearings, 6 hr. at 220F., Leakage 0.6/Nil 1.6/Nil m- m in grams/slump

A second grease was prepared by starting with the The static oxidation test for which data are given in base grease of Example 4 rather than with the soap 30 Table V was conducted in the following manner. Five concentrate. Methyl salicylate and lithium hydroxide grams of the grease being tested was packed into an monohydrate were reacted in the base grease at 220F. open ball bearing of known weight which was then in the same manner as described for the preparation of hung in an oven maintained at 350°F. At periodic inter Grease A, Example 5. The difference was that the vals the bearing was removed from the oven, and methyl salicylate and lithium hydroxide were reacted in 35 weighed again to determine weight loss of the grease. the finished base grease rather than in the soap concen The results were reported in terms of the number of trate. The product that was obtained was identified as hours for a 35% weight loss. Grease D. EXAMPLE 7 COMPARATIVE EXAMPLE - I Using the same general procedure as described in 40 Example 1, several grease formulations were made in The effect of omitting the dicarboxylic acid soaps which, in one instance, lower mole ratios of dibasic from the grease was determined by preparing a grease acid and methyl salicylate were used (Grease F), and in similar to greases A and Domitting the dilithium aze other instances a Co or a Cadibasic acid was used in late. The grease is identified as Grease E. place of azelaic acid (Greases G and H). The formula The properties of the base grease and of greases A, D 45 tions of these greases and their properties are given in and E are given in Table V which follows. Greases. A accompanying Table VI. An additional grease formula and D both have a mole ratio of 1 mole of hydroxyste tion (Grease I) wherein stearic acid was employed aric acid, 0.75 mole of azelaic acid, and about 0.7 mole instead of hydroxystearic acid resulted in a fluid prod of salicylic acid. The data obtained with grease E show uct containing undispersed soap rather than a grease. that the presence of the dicarboxylic acid soap is neces 50 Formulation J shows that a high dropping point grease sary in order to obtain a satisfactorily fine dilithium can also be obtained by forming dilithium salicylate in salicylate in the grease as well as to insure that the situ from salicylic acid instead of methyl salicylate. grease will have a dropping point of at least 500F. The data for greases G and H show that sebacic acid COMPARATIVE EXAMPLE - IA 55 can be satisfactorily used in place of azelaic acid but The formulation of Grease D was repeated, using the that a C acid (brassylic) did not produce a high drop same amounts of each component as for that grease, ping point grease. TABLE VI PREPARATION OF LITHIUM HYDROXYSTEARATE - DILITHIUM DICARBOXYLATE GREASES FORMULA Composition, Mole Ratio A F G H J 3.83 3.0 3.94 3.83 3.35 3.0 LiOH.HO - - - - 1.0 - Stearic Acid 1.0 1.0 1.0 1.0 - 1.0 12-Hydroxystearic Acid 0.75 0.55 - - 0.75 0.55 Azelaic Acid (C) - - 0.75 - -- Sebacic Acid (Co) -- -- 0.75 - - Dimethyl Brassylate (Cs) 0.67 0.50 0.72 0.67 0.43 - Methyl Salicylate - na - 0.50 Salicylic Acid Mineral Oil, 90 V.I., 550 SUS at 83.1 84.9 840 81.0 77.4 84.5 3,929,651 9 10 TABLE VI-continued PREPARATION OF LITHIUM HYDROXYSTEARATE - DILITHIUM DICARBOXYLATE GREASES FORMULA Composition, Mole Ratio A F G H I 100°F. Wt. 7, ASTM Penetration, 77°F. 60 Strokes, 305 317 300 317 Fluid 360 ASTM Dropping Point, F. 525 500 500- 396 - 520

This invention is not to be limited to the specific COMPARATIVE EXAMPLE - II examples given herein by way of illustration. Its scope Substituting 0.5 mole of lithium acetate for 0.5 mole is defined by the appended claims. of dilithium salicylate in Grease F gave a grease having What is claimed is: a dropping point of only 420°F. 1. A lubricating grease composition of high dropping 15 point and long oxidation life which comprises a major COMPARATIVE EXAMPLE - III proportion of a lubricating oil and from about 2 to 30 A grease similar to Grease G was prepared from one weight% of a thickener system whose essential compo mole of 12-hydroxy stearic acid, 0.75 mole of sebacic nents include a dilithium salt of a C-C dicarboxylic acid, and 0.80 of benzoic acid. The total amount of oil acid, a lithium soap of a C2 to Ca hydroxy acid, and a in the grease was 83.5%. The grease had an ASTM 20 lithium salt of a hydroxy aromatic carboxylic acid hav penetration of 336 at 77°F. and a dropping point of ing a maximum of 14 carbon atoms, wherein the hy 450°F. This compares with a dropping point of more droxy group is attached to a carbon atom not more than 500F. for Grease G, showing that the substitution than 6 carbon atoms removed from the carboxyl group, of a non-hydroxylated acid such as benzoic acid in in a weight ratio of about 0.5 to 15 parts of hydroxy place of a hydroxylated acid such as salicylic acid re 25 fatty acid per part of said dicarboxylic acid, and in a duces the dropping point of the grease. weight ratio of from about 0.025 to 2.5 parts of said hydroxy aromatic carboxylic acid per part of dicarbox EXAMPLE 8 ylic acid, said lithium salt of hydroxy aromatic carbox Using the procedure of Example 6 a grease was pre ylic acid having been prepared by reacting lithium base pared in which the acids used had a mole ratio of 1 30 with hydroxy aromatic carboxylic acid or lower alcohol mole of 12-hydroxystearic acid, 0.75 mole of azelaic ester thereof in the presence of dilithium salt of dicar acid and 0.75 mole of parahydroxy benzoic acid. A boxylic acid and lithium soap of hydroxy fatty acid. portion of the base grease of Example 4 was heated to 2. Composition as defined by claim 1 wherein the 180°F. and then the benzoic acid was added along with proportion of Ci to C4 hdyroxy fatty acid is from sufficient lithium hydroxide to convert the acid to a 35 about 1.5 to 5 parts by weight per part by weight of dilithium salt. The mixture was then heated for one-half dicarboxylic acid. hour at 230°F. and then dehydrated for 1 hour at 3. Composition as defined by claim 1 wherein the 300°F. The grease had a dropping point in excess of proportion of hydroxy, aromatic carboxylic acid is 500°F. and had an ASTM penetration of 325 at 76°F. from about 0.125 to 1.25 parts by weight per part by (330 after 60 strokes). The total thickener content of 40 weight of dicarboxylic acid. 4. Grease composition as defined by claim 1 wherein this grease was 18.1 wt.%. said hydroxy aromatic carboxylic acid is salicylic acid. EXAMPLE 9 5. Grease composition as defined by claim 1 wherein Following the procedure of Example 8, a grease was said hydroxy aromatic carboxylic acid is parahydroxy made using 0.75 mole of lactic acid instead of the 45 benzoic acid. parahydroxybenzoic acid. In this case, the base grease 6. Grease composition as defined by claim 1 wherein was made from an 87 V.I. oil having a viscosity of 600 said hydroxy fatty acid is 12-hydroxystearic acid. SUS at 100°F. rather than 550 SUS at 100°F. and 90 7. Grease composition as defined by claim 1 wherein V.I. The total thickener content of the grease as lithium said dicarboxylic acid is azelaic acid. salts was 15.3 wt.%. The dropping point of the grease 50 8. Grease composition as defined by claim 1 wherein was 515°F. and the grease had a penetration of 82°F. of said dicarboxylic acid is sebacic acid. 328 (332 after 60 strokes). ck k ck k k

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