US2348317A - Lubricant containing metal compounds - Google Patents

Description

gear lubricating compositions Patented May a, 1944 cosmonaucommons-ran comrolmn a 1 Stanley P. wuss. Westiield. n.1, to

Tidewater Associated N. J.-, acorporation ofDela Oil ware 'No Drawing. Applieation'llayzz, 1941, 1 Sa'ialNo.394,822",

I 'Q16Clainis. This invention "relates to improved mineral oil hibricattcompositions, and more particular- I! toimprovemenm known as extreme pressure lubricants.

For the past several automotive design has been toward engines of increased power. 1 This and other factors have resulted 'in operation of automobiles at higher and'more sustained speeds. In such operation the bearing surfaces oi gears such as transmission and diil'erential gears of the modern automobile are subjected toextremely high unit pressures in operation. This is particularly true in the case of diflerential gears ofthe hypoid type now commonly used.

It is well known in theautomotive art that the ordinary niiheralbii lubricants formerly employed do not adequately lubricate such gears under these high pressure conditions, and this situation has given rise to the development of known in the art as extreme, pressure or E. P. lubricants.

The conventional E. P. lubricants comprise a suitable mineral oil and an additional substance which imparts to the composition high loadcarrying capacity. .Inmost types of E. P. iubrinature since the lubricating eifectiveness of these compositions is apparently'due to the deposition upon thebea'ring surfaces of a high load-carrying film produced by chemicalreaction 'involv-Y ing the E.;P. agent. The-lubricat ng .eflectiveness of E. P. lubricants is thusnot due to'the viscosity and other characteristics of the mineral oil as in the case of the formerly .gear lubricants containing no E. P. 'agent', but is essentially attributable to theihigh load-carrying chemical nhn. V

Although some of the various extreme pressure lubricants heretofore proposed have proved successful ior certain uses, a great many have not been satisfactory, particularly for the lubrication of hypoid gears in automobiles and other automotive gears operating under particularly high pressure conditions, mainlybecaiise the additive agent fails to impart sufliciently highland-carryin: capacity to the compositions, and for other For example, it is known that the inin the type of compositions the tendency inor combined state, or certain a is that the E." Pjagent therein be of chemically. reactive (oi. zsa-asi j a corporation or free sulfur in mineral oils increases the load-carrying capacity over that of s cants. for hypoid gears and others under modern high-pressure p rating conditions in respect to load-carrying capacity, and for the additional reason that such compositions tend to cause-objectionable corrosion of the gear tooth surfaces.

10- Likewise; certain chlorine compounds and sulfur compounds provide some improvement in loadcarrying capacity but are insumciently eil'ective 'in this and other respects as E. P. ingredients for use in lubricants intended for the stated 1 services."

The present invention provides improved lubrigant compositions suitable and effective for the ilubrication of bearing surfaces operating under extremely highunit pressures. In'one 2 0.aspect the invention provides a means for in creasing the E.' P; properties and other desirable characteristics of lubricant compositions of the type normally considered efl'ective to some extent as extreme pressure lubricants for certain 26 lubrication services.

I have found in accordance with this invention that "compounds of antimony or bismuth are capable of "activating or promoting ex- 30 and thatby incorporating said metal compounds with said substances improved E. P.

lubricant compositions result. By this means the load-carrying capacity of'free sulfur-containingjmin'eral oils, for example, vcanbe increased from a point which as statedhereinabove isunsatisfactory iorlubrication of hypoid gears and the like to very satisfactory for tiveness in this respect of sulfur compounds, 40 chlorine compounds such, for instance, as those mentioned hereinabove, and others, can be likewise improved by incorporation of such metal compounds- Furthermore, the load-carrying capacities of certain initia y i ective E. P. lubrlcantcompositions' can be improved by incorporation of such'metal'compounds therein to thus provide a higher safety factor or assured ieflectiveness to mcetfuture lubrication demands as respects higher unit pressures between bearing to anticipate future use in the automotive field of engines oi increased power.

As agents for use as "activators" or promoters of E. P. properties when incorporatedaccording.

to this invention, I have found that both or- S me and inorganic compounds of antimony and the 'mineral'oil alone, but many such compositions fall far short of being satisfactory lubri-' treme pressure prop rties of, many substances a load-carrying capacity this purpose. The eil'ec- 1 and the antimony trichloride.

' to about of the-total composition.

ethylates, have proved particularly suitable Likewise cyclic or aromatic derivatives are effective, examples of these being aromatic stibines or bismuthines, for example trlphenyl stibines and triphenyl bismuthines. Soaps of such metals are also satisfactory. Among the latter.- class may be named soaps of cyclic nature such as naphthenates, for example antimonyhnaphthenates, or soaps of aliphatic straight chain acids. Antimony oleate may be mentioned as representative of the latter class. In general,- however, the metal soaps of the straight chain aliphatic acids are less effective than the other metal compounds discussed hereinabove.

The invention, broadly stated, comprises: lubricant compositions containing E. P. agents and having incorporated therein one or more metal compounds of the class described hereinabove which is effective to promote or increase the load-carrying capacity of said agent.

The exact reason why theaddition of thedescribed metal compoundsimproves the load-carrying capacity of these compositions is notknown. The improvement cannot be attributed to an additive eifect, inasmuch as the metal compounds themselves have no appreciable E. P. properties. In other words, the load-carrying capacity of a given lubricant composition of this invention. containing say free sulfur and antimony trichlorlde will be very much greater than the sum of the respective load-carryin capacities of the sulfur 'Ihe lubricant compositions of the invention the composition occurs. For example, in the case of mineral oil containing sulfur in which. antimony has been incorporated, heating to temperatures of around 180 1''. or above may cause precipitation of antimony sulfide, thus removing from solution important substances. Ordinarily temperatures up toabout 150-160 F. may be usedinthlsinstance.

The antimony or bismuth compounds are effec-' tive in .relatively small amounts, generally in als, howevergit hasbeen found that in some inresults than is required of other metal compounds. Antimonysoapsfor example, should be added in minimum proportions of from aboutib fia In order to; evaluate the working accordance with the instant invention such lubricants were tested on the S. A. E. lubricants tester.

. This machine is described in detail in B. A. B.

Journal, July 1936, page 293. It affords a recognised and standardized test for. determination of cants. Briefly, the machine comprises two rotab able hardened steel. test rin s rotated in opposite directions against each: other so as to make theoretical line contact at-their peripheries. The rings are rotated one clockwise at 890 R. P. H. and the other coimter-clockwise, the speed ratio being 14.8 to l, and a lever mechanism is provided for increasing the force between the hearing surfaces rate. The mechanical advantage of the lever is about 10 to 1 and a scale is provided which indi-. cates in pounds (up to 600 pounds) the force applied to the lever. The oilto be tested is continuously supplied at the rubbing-rolling surface at which the rings form mutual contact.

The pressure at which a given oil fails in this test is indicated by the scale reading-at the time when sparking occurs between the adjacent ring surfaces. Sparking indicates that the ring surfaces have become scored'or scufled and this may a be substantiated by subsequent inspection.

In the following tests on the S. A. E. tester the loading rate (scale) was 83.5 lbs/sec.

may be-prepared in any suitable manner. The metal'compound to be used-as the promoter may be simply stirred into a suitable mineral oil conproportions of about 10% or less on the basis of the vwhole composition and proportional amounts of about 1% have been found suitable .inmostca'ses. Inthecaseofsoapsofthesemet stances more is required to obtain satisfactory p a or load-carrying capacity of lubricants prepared in L actual load-carrying capacities, of E. P.- lubrl 1! Numerous lubricating compositions prepared in accordance with the present invention were tested on this machine. In these tests the following two blends of mineral oil were employed as the lubricant base for the indicated assistant and promoter:

In these blends. the cylinder stock used was an unfiltered residual oil having a Baybolt viscosity at 210 F. of about 180 seconds, the bright stock a fllteredresidual stock derived from a Pennsylvania crude having a Saybolt viscosity at 210' I". g

of approximately 150 and the pale oil a light-colored filtered oil having a Saybolt viscosity at I"; of approximately 200 seconds,

derived as anoverhead cut from a non-Pennsyl-v vanla crude. A third blend comprising heavy red oil, derived as distillate from a Columbian crude. and pale oil was aswillappear.

Itis,ofcwrse,understoodthattheseblends were selected merely as convenient oils for blendthelubricantwasflrstsubjectedtoamoresevere' heat test wherein said lubricant was heated at a temperature of 200 l".,fos 84 hours prior to the S.A.B.telst.

'In' the following tests of examples of lubricating compositions of the invention all withstood the maximum load of the 8. A. 3. machine as indicated by the fact that the maximum scale rea'dint was reachcdwithoutfailure or reduction in effectivenessof the lubricants.

m {as m rcdnsd mm mu: m a m. se -s e 5% antimony iloamyhte 2. above composition sullurised mineral oil oftheringsatadeflniteloadingalsousedillsomeofthetests an. wear "a; pale oil 44% pale es 1 added sulfur 1 .addedsullnr 1% cutaway isoamylate bimnth hoamylaie 33% pale oil I v The following test data from tests made on the A S. A. E. tester under the same test conditions as 1% added sulfur described hereinabove upon compositions similar 295mm? to those described but containing none of the %puleoil 1 i metal compounds of this invention afford com- 1 Wmtm parisongwhichbringout the efl'ect oftheaddi- 1% adde'd suliu rate tive activator or promoter agents: a in 0.8% oloicacid I 21. mieflnedcylinda-stockpailedaggl-gopmmgss A E 56% steam refined qlinderstock 22. mom.zrbmrenederiao eundes.a.n.ieetereene mg: 134% nex oil Beet ten-101m. a w r. l! %chlori'm2edm} readins ur drum and dS.A.E.testescalc fiaflmdylsoamylate I 2s 92% ponn s r N. b (isS.A.E.teste {amnesiarennede nnde;sleek I \qmizifilmiind meltdo n r 3 1% ,itwt l Hm e The fact that the lubricant compositions of the 2%oleic sold v instant invention withstand the maximum load 2% on thee. in E. tester indicates them to have out- 56%steamreflnedcylinderstock standing load-carrying properties. Although it m%{ {44% pfle oi] 11 .1; t t-u b Q m L was impossible to determine exact load at "1110mm which these compositions would fail, due to the 2% antimony boamylate steam refined cylinderstbck I corn oil (non-corrosive) 3% snty isosmylate steam relined cylinder stock 44 ll Z i....... see... 27: 8b isoemyiate y {56% steam refined cylinderstock.

W. 957 449 c all 0s%{ {0.6 add d uliur 6% chlor ted war 2% antimony isoarnyiate f. b naphthenate {56% steam refined cylinder stock 1% added suit 1% added sulfur 5% Sb naphthenate {56% steam refinedcylinder stock 447 e .oll Heat test-l6 hrs. 9 ill" I.

i 1% 'eddd unu boleste {56% steam refined cylinder stock 447 011 Heat test-l6 is. a no r. m add d arl hrr o I 8% Base 11% triphenylstibine W heavy red all limits of th testing machine, the condition of the test ring surfaces after the'tests indicated that even considerably higher loads would not cause failure. The surfaces of the used test rings were unusually smooth in contrast to suri'aces' of other rings which had been used in testing certain other good E. P. lubricants. The rings showed substantially no signs of wear and no evidence of sending or I An additional advantageous feature of the'compositions of the-invention resides in the fact that --the added metal compounds described also function to inhibit corrosion of metal surfaces of parts being lubricated by the composition. This is evidenced by the bright condition of the S. A. E. machine .test rings used in testing these lubricants. These rings showed no evidence of pitting or undue chemical attack after use in the Thus, use of the lubricants of this invention in heavy duty gear lubrication will result in prolonged 'geer life in protecting. the bearing surfaces thereof irom undesirable chemical attack as well as from rapid physical wear. Certain substances herteoi'ore used as E. P. ingredients which normally are of such high chemical activity as to cause undesirable corrosion may be stabilized or inhibited in" this respect by incorporation of the described metal compounds.

The described metal compound are desirably employed in solution in the mineral oil component, but need not be dissolved since they func--.

tion in suspension as well. the stated class which are soluble may if desired be r Metal compounds of substantially oil-indered soluble by first dissolving them in certain other substances. For

example, in preparing compositions numbered 18 and 19 hereinabove the antimony trichloride wasv first dissolved inpeanut oil and palm oil respectively,. and these mixtures were added to the mineral oil blends shown. Other solubillzing found effective, particularly pounds, are certain phosphate esters such, for phosphate. In some of the compositions, when allowed to stand for several hours, a slight sedl-- mcnt mayi'orm. This, however, inno way detracts from the efl'ecflveneu example, as lauryi as an E. P. lubricant.

Likewise, the mmbeeteuu e ui uee um eeide 8 11?! for antimony comwood fatty acids and certain 1 of the composition flooholates oi the. described being particularly advantageous for the par-pom. oleic acid, for example.-f1mctlons in the sulfur compositions (see Formulae 5, 6 and 'l) to stabilize the antimony alcoholates against hydrclization, thus preventing precipitation of antimony sulfide which may normally occur under high temperature conditions, such, for example, as is encountered in the heat tests of Examples 6 and f. The presence of oleic acid does not reduce the loadcarrying capacities of the compositions, which is surprising in view of the fact that the normal effect of oleic acid in E. P. lubricants is to reduce load-carrying capacity. p

In addition to gear lubricants the invention is also applicable to various other types of lubricants. For example, cutting oils and the like for use in extreme pressure metal working operations, and in general all lubricants for use where high bearing pressures exist,are included within the scope" of the invention. I The invention also includes methods of lubricating metal surfaces comprising applying thereto the compositions disclosed herein.

I claim:

1. A lubricant composition comprising an E. P. agent and chlorinated materials selected from the group consisting of sulfur, sulfurized materials and a compound of a metal of the group consisting of antimony and bismuth per se possessing no appreciable E. P. properties but bein effective to enhance the load-carrying capacity of said E. P. agent, the metal in said compound being in the monoatomicform.

2. A lubricant composition comprising mineral oil, an agent having load-carrying capacity selected from the group consisting of sulfursulfurized materials and chlorinated materials and a compound of a metal of the group consisting of antimony and bismuth per se possessing no appreciable load-carrying capacity but being effective to enhance the load-carrying capacity of said agent, the metal in said compound being in the monoatomic form.

3. An extreme pressure lubricant composition I comprising mineral oil and a substance normally having low load-carrying capacity selected from the group consisting of sulfur, sulfurized materials and chlorinated materials and a compound of the group consisting of antimony and bismuth soap effective to increase the load-carrying capacity of the sulfur.

'l. A lubricant composition comprising an E. P. agent selected from the group consisting of sulfur, sulfuriaed materials and chlorinated mate- 'rials and an alcoholate of a metal selected from the group'consisting of antimony and bismuth effective to enhance the load-carrying capacity of said E. P. agent.

8. A lubricantcomposition comprising a min-- eral lubricating oil. sulfur and an alcoholate of a metal selected from the group consisting of antimony and bismuth, said alcoholate being present in an amount sumcient to enhance the loadcarrying property of the sulfur.

9. A lubricant composition comprising a mineral lubricating oil, sulfur and a compound selected from the group consisting of antimony isoamylate and bismuth isoamylate, said compound being present in an amount-sufficient to enhance the load-carrying property of the sulfur,

10. A'lubricant composition comprising a mineral lubricating oil, a substance having load-carrying capacity selected from the group consisting of sulfur, sulfurized materials and chlorinated materials, and a compound of a metal selected from the group consisting of antimony and bis-' muth per se possessing no appreciable load-carrying capacity but being effective to enhance the load-carrying properties of the substance of the first named group, the metal in said compound being in the monoatomic form.

11. A lubricant composition comprising a mineral oil having dissolved therein sulfur and antiper se possessing no appreciable load-carrying I capacity, but being effective to enhance the loadcarrying capacity of said substance, the metal in said compound being in the monoatomic form.

4. A lubricant composition comprising a chicrinated material and a compound of a metal selected from the group consisting of antimony and bismuth effective to increase load-carrying capacity of said chlorine-containing compound.

5. A lubricant composition comprising mineral oil, sulfur and a compound of a metal of the .group consisting of antimony and bismuth per 'se possessing no appreciable load-carrying capacity but being effective to increase the load-carrying capacity of the sulfur, the metal in said compound being in the monoatomic form.

6. An extreme pressure lubricant composition comprising mineral oil, sulfur and anantimony effective to stabilize the solution, said antimony mony chloride, said antimony chloride being present in an amount suifloient to enhance the loadcarrying property of the sulfur..

12. A lubricant composition comprising a mineral oil containing sulfur, having dissolved therein antimony chloride and an agent effective to stabilize the antimony chloride, said antimony chloride being present in an amount sufficient to enhance the load-carrying property of the sulfur.

13. A lubricant composition comprising a sulfur-containing mineral oil having dissolved therein antimony chloride and a vegetable ol effective to stabilize the solution, said antimony chloride being present in an amount sufficient to enhance the load-carrying property of the sulfur.

14. An extreme pressure lubricant composition comprising a mineral oil having dissolved therein sulfur, an antimony alcoholate and a fatty acid alcoholate being present in an amount sufiicient to enhance the load-carrying property of the sulfur.

15. An extreme pressure lubricant composition as described in claim 14, in which the fatty acid is oleic acid.

16. An extreme pressure lubricant composition comprising mineral oil,- a-load-carrying agent selected from the group consisting of sulfur, sulfurized materials and chlorinated materials, and a stibine effective to enhance the load-carrying properties of said agent.

' STANLEY P. WAUGH.