US2911369A - High temperature grease containing free metal base and silicone polymer oil - Google Patents

Description

yention will become apparent 2,911,369 Patented Nov. 3, 1959 United States. Patent Ofiice HIGH TElVIPERATURE GREASE CONTAINING EIIQLEE NIETAL 'BASE AND SILICONE POLYMER 3% to about 500%, or more, and preferably from about 5% to about 200% based on the soap-content Ofjthe grease, of a basic compound such ajs"" basic alkaliinietal compounds, basic alkaline earthvcompounds, and high Stephen J. Zajac, Whiting, and Reuben A. Swenson, Hamj mond, Ind., assignors to Standard Oil Company, Chicago, Ill., a corporation of Indiana No Drawing. Application December 28, 1956 Serial No. 631,072

11 Claims. (Cl. 252-40 ,1 I Q 7 cate bearings operating at high temperatures. and which will not melt and/or lose consistency at such. operating temperatures. Other objects and advantages of the infrom' the following description thereof. l

US. Patent No. 2,684,944, issued July 27, 1954, to S. I. Zajac covers lithium polyorgano siloxane polymer greases containing 10% to 500% of a free basic compound, based on the lithium. soap content of the grease, which greases have high temperature stability characteristics. We have now found that the above objects can be attained with a lubricating grease comprising a major proportion of a lubricating oil, from about 0.5% to about 10%. of a normally liquid silicone polymer oil, 1% to about and preferably from about 2% to about 10% of a' metal soap of a high molecular Weight fatty acid, and a free basic compound in amounts. of from about 3.0% to about 500%, and preferably from about 5.0% to about 200%, based onthe soap content of the grease.

The metal soaps employed in the greasecompositions of the present invention are preferably the alkali metal and the alkaline earth soaps of unsaturated, partially unboiling basic organic nitrogen compounds, such as aliphatic or aromatic amines boiling above about 250 F.

Examples of suitable 'basic compounds are sodium hydroxide, potassium hydroxide, lithium hydroxide, lithium oxide, barium hydroxide, barium oxide, calcium hydroxide, calcium oxide, triphenyl amine, octylamine', etc.

The silicone oil polymer employed is suitably: a polymeric liquid compound having the general formula in which R R R R and R are the same or different hydrocarbon radicals, such as alkyl, aryl, alkaryl or aralkyl radicals and n is an integer greater than 1 De pending upon the extent'of condensation or polymerization, the polymer products vary from' relatively light liquids to solid resins. 'However, for the purpose of the present invention, polymers which are high boiling liquids Within the lubricating oil viscosity range are preferred. Commercially available compounds of this type are poly; mers of dimethylsilicone, diethyl silicone, ethylrnethyl silicone, diphenyl silicone, ditolyl silicone, methylphe'nyl I silicone, ethyl phenyl silicone, and the like. ,:Other silisaturated-or saturated fatty acids or hydroxy fatty acids having at least 12 carbon atoms, and preferably from about '12 to 22'or more carbon atoms. Examples of suitable fatty acids are lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid, hydrogenated fish oil fatty acids, hydrogenated castor oil, hydroxy stearic acid, e.g., 12-hydroxy stearic acid, and the like. The term high molecular weight fatty acid, as used herein and inv'the appended claims, means a fatty acid having at leastl2 carbon atoms. Examples of suitable metal soaps are lithium stearate, lithium 12-hydroxy stearate, sodium stearate, barium stearate, strontium soap of hydrogenated fish oil fatty acids, barium 12-hydroxy stearate, etc. Mixtures of such soap can also be used.

The. Specific effectiveness of the various fatty acids varies to some extent, the metal soaps of all of them, however, being effective tovarious degrees. It is, therefore, not' to be implied that the metal soaps of all of the herein-described fatty acids are equivalents.

The required excess alkalinity of the grease is supplied byincorporating in the grease composition from about cone polymers produced from high, molecular weight hydrocarbon groups, such as butyl, -1am 1, hexyl and above, when economically available can 1 also be used. Compounds of the type above described and the methods of preparing the same are described in-U.S. 2,352,974, 2,258,222, 2,371,068 and others. Polymeric organic; silicon compounds of this type are alsofreferred to ,as polymeric j dihydrocarbon siloxanes or ,polyor gano: 's'iloxan'es.

The lubricating oil vehicle usedjin the grease-can be a mineral oil in the lubricating oilviseosity'riari'ge, he, from about so S.S.U. at F. to about 300 s.s,U. at .2109 F., or a synthetic hydrocarbon oil such as is obtained-by the polymerization of unsaturated hydrocarbons; Other oleaginous materials within the lubricating oil range can be used, such as, for example high molecular weight polyoxyalkylene compounds such as polyalkylene glycol and esters thereof; aliphatic diesters of dicarboxylic acids such as the butyl, hexyl, ethyl hexyl,--decy-l,'lauryl, etc. esters of sebacic acid, adipic acid, azelaic acid, etc; polyfluoro derivatives of organic compounds, particularly hydrocarbons, such as tri-iluorovinyl chloride polymer, trifluoro chloroethylene polymer, etc. e

Greases of the present invention are easily"- prepare and donot require the use of solvents. iln', preparing greases of the present invention, all of the metal soap or soap constituents, all of the polyorgano siloxane, all of the basic compound, preferably in the form of anaqueous solution or suspension and a portionofithetoleaginous vehicle are mixed together, slowly heated to a temp'erature of about 212 F., and maintainedat' this temperatu'fe until the mixture is substantially free of'wat'er. When the mixture is substantially anhydrous, and foaming, if any, subsides, the remaining portion of the oleaginous vehicle is added, the batch heated to 'a'temperature of from about 450 F. to about 550" F., and 'pref'erablyto a temperature of about 500 F. to 510? F.',- andmaintained at said temperature until; thereaction is completed. The grease isthen filled and cooled. Thecooled product, if-desired, can be homogenized by well known'means.

The grease compositions of the present invention are illustrated by the examples in the following table:

I Lithium 12 hydroxy stearate, percent Lithium:hydroxidemonohydrate perc TABLE I Component Examples Silicone 011 (DC 550) percent Petroleum .Oil, Percent". SU Bt100 u Synthetic, Oil, Per

SSU at 100 F Penetration at 77 F.:

ked

. 100,000 strokes-.- Drop. Point,- 11--" Hotplate test at 700 T Soft 187 245 443 Too Soft 281 192 268 445 Too Soft 303 481 390 +450 348 327 N0 Melts No Melts Melts Change Change 1 DO 550-A silicone polymer oil 1 A polybutene having an average Di-isooctyl azelate. Example 1 is similar to the grease in Example 4 except for the addition of silicone oil and lithium hydroxrnarketed by Dow-Corning.

molecular weight of 330.

. i'de. Although. it is one grade softer in consistency, it

is much superior in high temperature properties.

Example 2 is a low soap content formulation containing lithium si-liconepolymer. Although it is a soft grease, it has very good high temperature properties.

Example 3 contains 50% less soap and-50% less silicone polymer than Example 2. Althoughit is a semi-fluid grease,.it has goodhigh temperature properties. When placed on a hot plate at 700 F., it maintains its shape and consistency. r

Example 4 included-for purpose of comparison is a commercial lithium hydroxy stearate grease commonly known as a lithium multipurpose grease.

Example 5 is a lithium hydroxy stearate grease made in vasynthetie oil. It. also contains silicone polymer. Comparison with Example 6 shows that the drop point of Example 5 is raised +90 F. bythe composition of the present invention. Example 7 is similar t'o Example 1, but contains no lithium hydroxide monohydrate. This example demonstrates thejnecessity for the free basic compound in the formulation.

The application of the presentkinvention to greases other than lithium soap greases is demonstrated by the date in Table II. p

TABLE 11.

Example No. Component Sodium Stearate, Percent 10. 5 10. 5 Dry Caustic Soda, Per t 0.75 'BariumStearate, Per 8. 7 8. 7 BariumHydroxide, Percent. 1.0 Silicone Oil (DC-550), Per nt 1. 5 1. 5 PetroleuInjOil, Percent 87.25 89.5 7 88.8 91.3 SSU' at 100 F 300 300 540 540 Penetration at 77". F.: I

' 'Unworked 232 315 286 399 -'Worked.. 236 j 280 214 373 Drop Point, "F +455 365 +460 ,Example 1 is a sodium soap grease made in accordance :with'the present invention and Example 2 is a conventional :sodium soap grease made without the excess free alkali and siliconeoil; The improved penetration and drop point properties of Example 1 are clearly shown.

Example 3 is a barium soap grease made by the present invention, while Example 4 is a'conventional barium soap grease-containing noexcess tree alkalinity and no silicone oil. Here again the improvement obtained by the present invention is demonstrated.

TABLE III I Metal hydroxide requirement Lithium 12-hydroxy stearate. Percent 7.0 7.0 6.0 7.0 6. 0 Lithium Hydroxide monohydrate,

Percent. 0. 25' 0.50 0. 75 1. 0. Silicone. oil (DO-550), Percent 1. 5 1. 5 1.5 1.5 1.5 Petroleum oil, Percent 91. 5 91. 25 92.0 90.75 91: 5 8.5.1]. at F 813 813 813 813 813 Penetration:

Unworked 443 423 34 321 318 or e 445 426 336 320 309 100,000 Strokes 481 50g; 349 .330 320 o Drop point, "F 327 343 429 +450 +455 In Table HI the only ingredient variable is lithium hydroxide. The silicone oil content is constant at 1.5 The high temperature stability and lubricating characteristics of the greases of the presentinvention are given in Table IV together with comparative data for a conventional lithium soap grease. f

ABEO-NLGrI-Teclinlottl Bulletin No. '5Novembcr 1944. Periormancecharacteristics of lubricating grease in anti-friction bearings at elevated temperatures.

The grease of Example 3 was a conventional so-called multipurpose grease.

The high temperature stability" property of the greases made in accordancewith the present invention cannot be obtained by mixtures of conventional greases and the high temperature stability greases of my US. Patent 2,684,944. This is demonstrated by the data in Table V.

TABLE V Drop Sample Product; PgiFnt,

Conventional lithium lz-hydroxy stearate grease" 385 Lithium silicone oil grease oi U.S. 2,684,944 600 90% A+10% B 386 Anhydrous calcium soap greas 289 90% D+10 B 289 Hydrous calcium soap grease 217 90% F+ B 21s Composition of grease A: Percent .Hydrogenated fatty acid 0.69 Hydrogenated castor oil 5.90 Lithium hydroxide, H O 0.90 Ortholeum 300 0.27 Phenothiazine 0.07 Solvent extracted 40 oil 91.17

Composition of grease B:

Lithium hydroxy stearate 1.5 Lithium hydroxide, H O 1.5 DC 550 Silicone Oil 97.0

Composition of grease D:

IZ-hydroxy stearic acid 7.81 Acetic acid 5.86 Lime .50 Solvent extracted 40 oil 85.83

Composition of grease F Fatty acids 17.00 Hydrated lime 2.21 Dry caustic soda 0.14 Water 0.65 Petroleum oil 80.00

The above data show that the mere mixing of a grease of Patent US. 2,684,944 and a conventional petroleum oil grease will not give a product having the high temperature characteristics of the grease product of the herein-described invention.

The greases of the present invention can contain added constituents such as anti-oxidants, oiliness agents, extreme lar weight polyalkylene glycol from about 0.5 to about 10% of a normally liquid silicone polymer oil in the lubricating oil viscosity range, from about 1% to about 20% of a metal soap of a high molecular Weight fatty acid selected from the group consisting of an alkali metal soap, an alkaline earth soap and mixtures thereof, and from about 3% to about 500%, based on the metal soap content of said composition, of a free basic compound selected from the group consisting of an alkali metal hydroxide, an alkali metal oxide, an alkaline earth hydroxide and an alkaline earth oxide.

2. A lubricating grease composition as described in claim 1 in which the metal soap is a lithium soap.

3. A lubricating grease composition as described in claim 1 in which the metal soap is lithium 12-hydroxy stearate.

4. A lubricating grease composition as described in claim 1 in which the metal soap is the lithium soap of hydrogenated castor oil.

5. A lubricating grease composition as described in claim 1 in which the metal soap is a sodium soap.

6. A lubricating grease composition as described in claim 1 in which the metal soap is a barium soap.

7. A lubricating grease composition as described in claim 1 in which the free basic compound is a lithium hydroxide.

8. A lubricating grease composition as described in claim 1 in which the free basic compound is sodium hydroxide.

9. A lubricatinggrease composition as described in -claim 1 in which the free basic compound is hydrated pressure additives, anti foam agents, etc. without in any way departing from the scope of the invention.

Percentages given herein and in the appended claims are weight percentages unless otherwise specified.

While we have described our invention by reference to specific preferred embodiments thereof, it is not intended that the. invention be limited thereto, but includes within its scope such modifications and variations as come within the spirit of the appended claims.

We claim:

1. A lubricating grease composition comprising a major proportion of a lubricating oil selected from the group consisting of a hydrocarbon oil, a .diester of a dicarlime.

10. A lubricating grease composition as described in claim 1 in which the free basic compound is barium hydroxide.

11. A lubricating grease composition comprising a major proportion of a hydrocarbon lubricating oil, from about 0.5% to about 10% of a normally liquid silicone polymer oil in the lubricating oil viscosity range, from about 1% to about 20% lithium 12-hydroxy stearate and from about 3% to about 500%, based on the lithium soapcontent of said composition, of lithium hydroxide.

References Cited in the file of this patent UNITED STATES PATENTS 2,417,428 McLennan Mar. 18, 1947 2,684,944 Zajac July 27, 1954 2,831,812 Worth Apr. 22, 1958 FOREIGN PATENTS 736,921 Great Britain Sept. 14, 1955 OTHER REFERENCES Manufacture and Application of Lubricating Greases, Boner, Reinhold Pub. Corp., N.Y., 1954, p. 488.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Noa 2,911,369 November 3, 1959 Stephen J a Zajac st alu It is hereby certified that error appears in the printed specification of the above numbered patent requiring correct-ion and that the said Letters Patent should read as corrected below.

Column 2, line 17', after "which" insert M R, column 3, line 48, for "date" read data as Signed and sealed this 10th day of May 196D.)

Attest: a, I

KARL H AXLINE ROBERT C. WATSON Attesting Oflicer Commissioner of Patents

Claims (1)

1. A LUBRICATING GREASE COMPOSITION COMPRISING A MAJOR PROPORTION OF A LUBRICATING OIL SELECTED FROM THE GROUP CONSISTING OF A HYDROCARBON OIL, A DIESTER OF A DICARBOXYLIC ACID AND AN ALIPHATIC ALCOHOL, AND A HIGH MOLECLAR WEIGHT POLYALKLENE GLYCOL FROM ABOUT 0.5 TO ABOUT 10% OF A NORMALLY LIQUID SILICONE POLYMER OIL IN THE LUBRICATING OIL VISCOSITY RANGE, FROM ABOUT 1% TO ABOUT 20% OF A METAL SOAP OF A HIGH MOLECULER WEIGHT FATTY ACID SELECTED FROM THE GROUP CONSISTING OF AN ALKALI METAL SOAP, AN ALKALINE EARTH SOAP AND MIXTURES THEREOF, AND FROM ABOUT 3% TO ABOUT 500%, BASED ON THE METAL SOAP CONTENT OF SAID COMPOSITION OF A FREE BASIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF AN ALKALI METAL HYDROXIDE, AN ALKALI METAL OXIDE, AN ALKALINE EARTH HYDROXIDE AND AN ALKALINE EARTH OXIDE.