2,911,369 United States Patent Office Patented Nov. 3, 1959

1. 2 3% to about 500%, or more, and preferably from about 2,911,369 5% to about 200% based on the soap content of the HGH TEMPERATURE GREASE CONTAINING grease, of a basic compound such as basic EE METAL BASE AND SILICONE POLYMER compounds, basic alkaline earth compounds, and high O - - 5 boiling basic organic nitrogen compounds, such as ali phatic or aromatic amines boiling above about 250 F. Stephen J. Zajac, Whiting, and Reuben A. Swenson, Ham Examples of suitable basic compounds are sodium hy mond, Ind., assignors to Standard Oil Company, Chi droxide, potassium hydroxide, hydroxide, lithium cago, Ill., a corporation of Indiana oxide, barium hydroxide, barium oxide, calcium hy No Drawing. Application December 28, 1956 O droxide, calcium oxide, triphenyl amine, octylamine, etc. Serial No. 631,072 The silicone oil polymer employed is suitably, a poly 11 Claims. (C. 252-40) . meric liquid compound having the general formula i. R. This invention relates to high temperature greases and 15 R-Si-O-S-R. more. particularly pertains to alkali metal and alkaline R2 R4 earth metal soap greases having high temperature stability in which R1, R2, R3, Ra, and R5 are the same or different characteristics and to the method of preparing such hydrocarbon radicals, such as alkyl, aryl, alkaryl or greases. aralkyl radicals and n is an integer greater than 1. De It is an object of the present invention to provide a 20 pending upon the extent of condensation or polymeri lubricating grease which is stable at high temperatures zation, the polymer products vary from relatively light with respect to consistency and which is resistant to leak liquids to solid resins. However, for the purpose of the age at high temperatures. Another object of the inven present invention, polymers which are high boiling liquids tion is to provide metal soap greases having high drop within the lubricating oil viscosity range are preferred. ping points. Still another object of the invention is to 25 Commercially available compounds of this type are poly provide lubricating greases which will effectively lubri mers of dimethylsilicone, diethyl silicone, ethylmethyl cate bearings operating at high temperatures and which silicone, diphenyl silicone, ditolyl silicone, methylphenyl will not melt and/or lose consistency at such operating silicone, ethyl phenyl silicone, and the like. Other sili temperatures. Other objects and advantages of the in cone polymers produced from high. molecular weight vention will become apparent from the following descrip 30 hydrocarbon groups, such as butyl, amyl, hexyl and tion thereof. - above, when economically available can also be used. U.S. Patent No. 2,684944, issued July 27, 1954, to Compounds of the type above described and the methods S. J. Zajac covers lithium polyorgano siloxane polymer of preparing the same are described in U.S. 2,352,974, greases containing 10% to 500% of a free basic com 2,258,222, 2,371,068 and others. Polymeric organic sili pound, based on the content of the grease, 35 con compounds of this type are also referred to as poly which greases have high temperature stability characteris meric dihydrocarbon siloxanes or polyorgano siloxanes. tics. We have now found that the above objects can be The lubricating oil vehicle used in the grease can be a attained with a lubricating grease comprising a major mineral oil in the lubricating oil viscosity range, i.e. from proportion of a lubricating oil, from about 0.5% to about about 50 S.S.U. at 100° F. to about 300 S.S.U. at 210 10% of a normally liquid silicone polymer oil, 1% to 40 F., or a synthetic hydrocarbon oil such as is obtained by about 20%, and preferably from about 2% to about 10% the polymerization of unsaturated hydrocarbons. Other of a metal soap of a high molecular weight fatty acid, oleaginous materials within the lubricating oil range can and a free basic compound in amounts of from about be used, such as, for example high molecular weight poly 3.0% to about 500%, and preferably from about 5.0% to oxyalkylene compounds such as polyalkylene glycol and about 200%, based on the soap content of the grease. 45 esters thereof; aliphatic diesters of dicarboxylic acids such The metal soaps employed in the grease compositions as the butyl, hexyl, ethylhexyl, decyl, lauryl, etc. esters of the present invention are preferably the alkali metal of sebacic acid, adipic acid, azelaic acid, etc.; polyfluoro and the alkaline earth soaps of unsaturated, partially un derivatives of organic compounds, particularly hydrocar saturated-or saturated fatty acids or hydroxy fatty acids . . bons, such as trifluorovinyl chloride polymer, trifluoro having at least 12 carbon atoms, and preferably from 50 chloroethylene polymer, etc. - - - - - ...... about 12 to 22 or more carbon atoms. Examples of Greases of the present invention are easily-prepared suitable fatty acids are lauric acid, myristic acid, palmitic and do not require the use of solvents. In preparing acid, , behenic acid, oleic acid, hydrogenated greases of the present invention, all of the metal soap or fish oil fatty acids, hydrogenated castor oil, hydroxy soap constituents, all of the polyorgano siloxane, all of stearic acid, e.g., 12-hydroxy stearic acid, and the like. 55 the basic compound, preferably in the form of an aqueous The term "high molecular weight fatty acid,” as used solution or suspension and a portion of the oleaginous herein and in the appended claims, means a fatty acid vehicle are mixed together, slowly heated to a temperature having at least 12 carbon atoms. Examples of suitable of about 212 F., and maintained at this temperature metal soaps are lithium stearate, lithium 12-hydroxy until the mixture is substantially free of water. When stearate, sodium stearate, barium stearate, strontium soap 60 the mixture is substantially anhydrous, and foaming, if of hydrogenated fish oil fatty acids, barium 12-hydroxy any, subsides, the remaining portion of the oleaginous stearate, etc. Mixtures of such soap can also be used. vehicle is added, the batch heated to a temperature of The specific effectiveness of the various fatty acids from about 450° F. to about 550 F., and preferably to varies to some extent, the metal soaps of all of them, a temperature of about 500F. to 510 F., and main however, being effective to various degrees. It is, there 65 tained at said temperature until the reaction is completed. fore, not to be implied that the metal soaps of all of the The grease is then filled and cooled. The cooled product, herein-described fatty acids are equivalents. if desired, can be homogenized by well known means. The required excess alkalinity of the grease is supplied The grease compositions of the present invention are by incorporating in the grease composition from about illustrated by the examples in the following table: . . 2,911,369

TABLE I Examples Component

Lithium 12-hydroxy stearate, percent. - monohydrate, per Silicone Oil (DC 550),1 percent Petroleum Oil, Percent.-- PetroleumSSU at Polymer100 F------Oil, Percent. - SSU at 100 F------Synthetic. Oil, Percent SSU at 100 F------Penetration at 77 F.: Too Soft 294 187 245 443 Too Soft 28. 92 268 445 UnWorked------Worked------321320 347341 100,000 strokes- 330 ------Too Soft 808------481 Drop Point, F------450 - 460 ------No- - - - Melts390 -:450No Melts348 Melts327 Hotplate test at 700 F------C------No No - - Change. Change Change Change DC 550-A silicone polymer oil marketed by Dow-Corning. A polybutene having an average molecular weight of 330. . Di-isooctyl azelate. Example 1 is similar to the grease in Example 4 ex silicone oil. Here again the improvement obtained by cept for the addition of silicone oil and lithium hydrox the present invention is demonstrated. ide. Although it is one grade softer in consistency, it The effect of the free basic compound is demonstrated is much superior in high temperature properties. 25 by the data in the following Table III. Example 2 is a low soap content formulation contain ing lithium silicone polymer. Although it is a soft TABLE III grease, it has very good high temperature properties. Metal hydroxide requirement Example 3 contains 50% less soap and 50% less silicone polymer than Example 2. Although it is a semi-fluid 30 grease, it has good high temperature properties. When placed on a hot plate at 700 F., it maintains its shape Lithium 12-hydroxy stearate, Per- 7. o and consistency. - - - - - Lithiumhydroxidecent------monohydr 7.0 : 6.0 6.0 Example 4 included for purpose of comparison is a Percent------0.25 0.50 0.75 1.0. commercial lithium hydroxy stearate grease commonly 35 Silicone, oil (DC-550), Percent. .5 15 5 5. Petroleum oil, Percent------9.25 92.0 90.75 91.5 known as a lithium multipurpose grease. S.S.U. at 100 F------83 813 83 '813 813 Example 5 is a lithium hydroxy stearate grease made Penetration: . .- Unworked.------443 423 340 32. 38 in a synthetic oil. It also contains silicone polymer. Worked------445 426 : 336 320 309 Comparison with Example 6 shows that the drop point 100,000 strokes 481. SR 349 330 320 of Example 5 is raised --90 F. by the composition of 40 Ot. the present invention. Drop point, F------327 429 --450 +455 Example 7 is similar to Example 1, but contains no lithium hydroxide monohydrate. This example dem In Table III the only ingredient variable is lithium onstrates the necessity for the free basic compound in the hydroxide. The silicone oil content is constant at 1.5%. formulation. 45 The high temperature stability and lubricating charac The application of the present invention to greases teristics of the greases of the present, invention are given other than lithium soap greases is demonstrated by the in Table IV together with comparative data for a con date in Table II. . . . ventional lithium soap grease. - TABLE II. 50 TABLE IV Example No. Oomponent -- Component 2 3 4. 55 Sodium Stearate, Percent------10.5 10.5 -...-...--- Dry Caustic Soda, Percent. - 0.75 Lithium 2-hydroxy stearate, Percent.------8.80 Barium Stearate, Percent Lithium hydroxide, monohydrate, Percent--- 1.73 1.0 Barium Hydroxide, Percent---- Silicone Oil (DC 550), Percent------.00 ------Silicone Oil (DC-550), Percent Petroleum Oil, Pereent------88.47 905 Petroleum Oil, Percent. SSU at 100 F------83 300 SSU at 100°F. Penetration at 77.F Penetration at 77 Unworked------314 314 Unworked. 232 315 286 399 Worked - - - - 309 308 Worked--- 236: 280 24 373 Drop Point, F------480 38: Drop Point, 9F --455 365 - 460 341 10,000 r. p.m. Bearing Test 1 at 350° F., Hrs.-- 126 20 65 formance1 ABEC-NLGI-Technical characteristics of lubricating Bulletin greaseNo. 5-November in anti-friction 1944. bearings Per at elevated temperatures. : - Example 1 is a sodium soap grease made in accord ance with the present invention and Example 2 is a con The grease of Example 3 was a conventional so-called ventional sodium soap grease made without the excess 70 multipurpose grease. free alkali and silicone, oil. The improved penetration The high temperature stability property of the greases and drop point properties of Example 1 are clearly shown. made in accordance with the present invention cannot Example 3 is a barium soap grease made by the present be obtained by mixtures of conventional greases and the invention, while Example 4 is a conventional barium high temperature stability greases of my U.S. Patent soap grease containing no excess free alkalinity and no 75 2,684,944. This is demonstrated by the data in Table V. 2,911,369 5 6 TABLE V boxylic acid and an aliphatic alcohol, and a high molecu lar weight polyalkylene glycol from about 0.5 to about Drop 10% of a normally liquid silicone polymer oil in the Sample Product Pgp, lubricating oil viscosity range, from about 1% to about 20% of a metal soap of a high molecular weight fatty A.------Conventional lithium 12-hydroxy stearate grease-- 385 acid selected from the group consisting of an alkali B------Lithium silicone oil grease of U.S. 2,684,944.------600 metal soap, an alkaline earth soap and mixtures thereof, --Anhydrous- 90% A-10% calcium B------Soap grea - 289386 and from about 3% to about 500%, based on the metal -- 90% D-10% B------289 Hydrous calcium soap grea 217 soap content of said composition, of a free basic com G------90% F-10% B------218 pound selected from the group consisting of an alkali metal hydroxide, an alkali metal oxide, an alkaline earth. Composition of grease 'A': Percent hydroxide and an alkaline earth oxide. Hydrogenated fatty acid ------0.69 2. A lubricating grease composition as described in Hydrogenated castor oil ------5.90 claim 1 in which the metal soap is a lithium soap. Lithium hydroxide, H2O ------0.90 5 3. A lubricating grease composition as described in Ortholeum 300 ------0.27 claim 1 in which the metal soap is lithium 12-hydroxy Phenothiazine ------0.07 stearate. Solvent extracted 40 oil ------91.17 4. A lubricating grease composition as described in claim 1 in which the metal soap is the lithium soap of Composition of grease “B”: 20 hydrogenated castor oil. Lithium hydroxy Stearate ------1.5 5. A lubricating grease composition as described in Lithium hydroxide, H2O ------1.5 claim 1 in which the metal soap is a sodium soap. DC550 Silicone Oil ------97.0 6. A lubricating grease composition as described in Composition of grease "D': claim 1 in which the metal soap is a barium soap. 12-hydroxy stearic acid ------7.81. 25 7. A lubricating grease composition as described in Acetic acid ------5.86 claim 1 in which the free basic compound is a lithium. Lime ------50 hydroxide. Solvent extracted 40 oil ------85.83 8. A lubricating grease composition as described in claim 1 in which the free basic compound is sodium Composition of grease "F": 30 hydroxide. Fatty acids ------17.00 9. A lubricating grease composition as described in Hydrated lime ------2.21 i claim 1 in which the free basic compound is hydrated Dry caustic soda ------0.14 lime. Water ------0.65 10. A lubricating grease composition as described in Petroleum oil ------80.00 35 claim 1 in which the free basic compound is barium hy The above data show that the mere mixing of a grease droxide. of Patent U.S. 2,684,944 and a conventional petroleum 11. A lubricating grease composition comprising a ma oil grease will not give a product having the high tem jor proportion of a hydrocarbon lubricating oil, from perature characteristics of the grease product of the about 0.5% to about 10% of a normally liquid silicone herein-described invention. 40 polymer oil in the lubricating oil viscosity range, from The greases of the present invention can contain added about 1% to about 20% lithium 12-hydroxy stearate constituents such as anti-oxidants, oiliness agents, extreme and from about 3% to about 500%, based on the lithium pressure additives, anti-foam agents, etc. without in any soap content of said composition, of lithium hydroxide. way departing from the scope of the invention. Percentages given herein and in the appended claims 45 References Cited in the file of this patent are weight percentages unless otherwise specified. UNITED STATES PATENTS While we have described our invention by reference to specific preferred embodiments thereof, it is not in 2,417,428 McLennan ------Mar. 18, 1947 tended that the invention be limited thereto, but includes 2,684944 Zajac ------July 27, 1954 within its scope such modifications and variations as come 50 2,831,812 Worth ------Apr. 22, 1958 within the spirit of the appended claims. FOREIGN PATENTS We claim: 1. A lubricating grease composition comprising a ma 736,921 Great Britain ------Sept. 14, 1955 jor proportion of a lubricating oil selected from the group OTHER REFERENCES consisting of a hydrocarbon oil, a diester of a dicar 55 Manufacture and Application of Lubricating Greases, Boner, Reinhold Pub. Corp., N.Y., 1954, p. 488. UNITED STATES PATENT OFFICE s CERTIFICATE OF CORRECTION Patent No. 2,911,369 November 3, 1959 Stephen J. Zajac et al. It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

for "date"Column read 2 line-- data 17, asafter "which" insert ad. R -- column 3 iine 28 Signed and sealed this 10th day of May 1960.

(SEAL) Attest: - KART. H. AXT.INE ROBERT C. WATSON Attesting Officer Commissioner of Patents