US2921903A - Extreme pressure lubricants - Google Patents

Description

United States Patent EXTREME PRESSURE LUBRICANTS Helen Sellei Beretvas, Chicago, 111., assignor to Standard Oil Company, Chicago, 111., a corporation of Indiana No Drawing. Application June 28, 1954 Serial No. 439,869

Claims. (Cl. 252-37.2)

This invention relates to improved extreme pressure lubricants and the method of preparing same. It is particularly concerned with improvements in such lubricants containing lead naphthenate, a sulfurized organic compound and a chlorinated organic compound.

Extreme pressure lubricants containing lead, sulfur and chlorine are well known to those skilled in the art and considerable research has been conducted for the purpose of improving the load-bearing properties as Well as other extreme pressure characteristics of such lubricants. Such research has primarily been directed to the discovery of new sulfur and/or chlorine containing compounds which would yield their chlorine and sulfur more readily and thereby exhibit improved extreme pressure characteristics. Despite the large sums expended on research and the vast amount of time involved in investigating the effectiveness of the many sulfur and/or chlorine organic compounds, however, the .art has not discovered any truly outstanding additives of this type which are widely accepted over the many analogous compounds. Consequently, it has long been felt that a desirable approach to the problem might be an additive which would increase the etfectiveness of lead, sulfur, and chlorine containing lubricants and which would be generally applicable to the wide range of different sulfur and chlorine containing additives employed. It has now been found that the properties of sulfur and chlorine containing E.P. additives (extreme pressure additives) can be greatly enhanced and the overall effectiveness of lubricants containing lead naphthenate along with sulfur and chlorine containing E.P. constituents improved to a large extent by the addition of a minor amount of oleic acid.

In accordance with the present invention, lubricants comprising a mineral lubricating oil in the higher vis cosity range, ordinarily employed in lubricants of this type, e.g. from about 45 to about 180 S.S.U. at 210 F. and preferably from about 75 to about 110 S.S.U. at 210 F., and containing a lead naphthenate, one or more organic sulfur containing EP. agent and an effective amount of a chlorine containing E.P. agent may be rendered more effective by combining therewithan amount of oleic acid of from about 1 to about and preferably from about 2 to about 7%. Such lubricants may, of course, also contain efiective quantities of various other typical lubricant additives such as antioxidants, detergents, etc. It should be understood that the lubricants of the type discussed herein are those useful principally in the automotive use, e.g. in the hypoid gear of rear axles, etc., as opposed to the socalled extreme pressure or, more properly, extreme temperature lubricants employed in steel mill rolling operations, etc. The latter type of lubricant ordinarily contains viscous hydrocarbon oils such as asphalts or residuums and is a quite different type of product generally unsuited to the requirements of automotive or like use.

The amount of lead naphthenate employed in extreme pressure lubricants of the present invention may vary over a relatively wide range depending upon a variety of factors, e.g. the end use of the lubricant, the lubricatr6 ICC ing oil employed, the sulfur :and, chlorine content, etc.

In any event, oleic acid has been found to improve the properties of lead soap containing extreme pressure lubricants having as little as about'.1.'5% of lead naph- 5 thenate containing between about 25 and 30% lead.

The oleic acid is, however, useful in lubricants containing substantially greater amounts of lead naphthenate, e.g. as much as 10% of such a soap, and even higher resulting in lead contents-as high as about 3% and higher.

In order to demonstrate thelimprovement obtained when employing oleic acid in lead, sulfur and chlorine containing extreme pressure lubricants of the type herein described, data are set forth below which were obtained on the Timken testing machine. Such test is well known to those skilled in the art as being useful in affording valuable information with respect to the potential commercial value of extreme pressure lubricants. The Timken machine and test are fully described in the Journal of the Institute of Petroleum 32, pp. 209210 and 220-222 (1946).

The data set forth in Table I were obtained with an acid treated SAE 50 grade mineral lubricating oil containing in each instance 5% sulfurized sperm oil which comprised 10 to 13% sulfur and 3% of a chlorinated hydrocarbon containing 73% chlorine. The data in Table 2 on the other hand were obtained on sample also containing varying amounts of chlorine, sulfur and lead. The latter were also employed in an SAE 50 grade oil and tested in the Timken machine.

Table 1.

lreag O1 d gimlren Test ap em 0: esu ts, L d, Run No. thenate (Wt. per- Lbs. 0a

(Wt. percent) cent) Pass Fail 1! 5 None 35 l 5 2 B 4. 2 6. 8 6O 1 Commercial basic lead naphthenate (30% Pb).

Table :2

5O Timken Test ResultsLoad, Lbs, With Varying Oleic Percent Percent AcidContents Percent Sulfurized Chlori- Run Pb Naph E.P. nated 1 thenate Agent b E.P. None 2% 4% Agent 55 J I Pass Fail Pass Fail Pass Fail ggllillfllel'glal basic lead naphthenate7(30% Pb).

urize sperm eontainin 101:0 13 sulfur, exce t wh c Benzyldisulfide (26% s). g 0 p Ere noted d Commercial chlorinated hydrocarbon containing 73% C (OH73- product of Pennsylvania Salt Manufacturing-00.),except where other- WISBO noted. I m dh ommercia c orinate ydrocarbon eontainin 4042 C1 010" fin 42, product of Hercules Powder 00.). g la Whereas the correlation of results of the Timken test or any other laboratory technique with operational effectiveness is sometimes difficult, it has become apparent that the oleic acid results in improved results in both laboratory and operational tests. Actual field testsin the rear axle of a major automobile manufacturer has demonstrated the outstanding utility of extreme pressure lubricants containing oleic acid. The manner in which the oleic acid contributes to such improvement and the effect that it hason'the lubricant is not "any understood; However, in addition to its efiectiveness in "increasing load-bearing properties of an extreme pressure oil, it 'has been found to contribute to the stability of the lubricant ltself by contributing in large measureto the solubilization ef the variousadditives and particularly'the lead containing soaps.

In connection, howeverfwith the solubilization of the various additives in an extreme pressure lubricantand particularly the solubilization of lead soaps of various kinds and the other E.P. additives employed, it has been found that even the use of oleic 'acid does not always result in completely stable oils from which the additives do not settle out during storage. And it has been found that certain alkyl phenols" when employed relatively minor quantities will enhance thesolubility of the various extreme pressure additives, particularly the lead soaps. Thus, monoand dialkyl phenols containing a total of from about 8 to about 12"carbon atoms in the alkyl'side chain or chains have been found to be exceptionally effective in maintaining a stable extreme pressure lubricant containing a lead soap with the sulfur and chlorine contaming constituents. Such alkyl phenols as dibutyl phenol, diamyl phenol, dihexyl phenol, n-octyl phenol, 2-ethyl hexyl phenol, nonyl. phenols, decyl phenols, dodecyl phenols, etc. may be advantageously employed. These phenols may be employed inE.P. oils of the type described in amount of fiom about 1 to about and preferably from about 2 to about 6%; In any event, if two alkyl chains are present, neither preferably contains less than four carbons.

Set forth in Table 3 are data demonstrating the effectiveness of alkyl phenols, both of the monoand dialkyl The data in Table 3 were obtained from certain extreme pressure gear oils, each of which contained, in addition to the materials set forth in Table 3, 5% sulfurized sperm oil (11% sulfur), 6% chlorinated hydrocarbon 40-42% chlorine), 0.3% dodecyl hexasulfide. The oil employed was an acid treated oil having the viscosity of 90 S.S.U. at 210 F. Two to 5 parts per million of a silicone antifoam agent was contained in the oil.

3 Although the specific materials employed int he various tests set forth above were a sulfurized sperm oil and a chlorinated hydrocarbon, it should be understood that many other known sulfur and/ or chlorine-containing materials may be employed in conjunction with the lead soaps of the present invention; Thus, sulfurized hydrocarbons, sulfurized carboxylic acids, e.g. sulfurized tall oil, sulfurized oleic acid, etc., organic sulfides, sulfurized vegetable oils, polysulfides, e.g. the dialkyl tri-, tetra-, pentaand hexasulfides, and other oil-soluble sulfurcontaining compounds or materials useful in extreme pressure lubricants, may be employed in accordance herewith. Reference is made to US. 2,136,391, 2,202,394, and manyother patents disclosing sulfur-containing additives for extreme pressure addition; such materials are generally useful in accordance herewith. The expression sjulfur-containing E.P. additive or similar expression is generally descriptive of these sulfur-containing organic constituents which may be employed in extreme pressure lubricants. And they, generally, are useful in accordance herewith in an amount sufiicient to afiord a sulfur content. of from about 0.2 to about 3.0% and preferably from about 0.3 to about 1.0%. It should be understood that additional amounts of sulfur may be introduced by the base oil or the solvent extract solubilizer (if one is type, in maintaining a stable extreme pressure lubricant 1 of from June to November, when the range of tempera-,

ture variation is. great. -It wil be noted'that a minor amount of Chlorex (B,B'-dichlorodiethylether) extract was employed as an additional solubilizing agent in two' examples. The presence of such an extract enhances the stability of the oil but its use is usually not necessary when employing the alkyl'phenol. lubricating oil base stocks may also 'be employed with advantage; thus, for'example, 'extractsresulting from treatment of lubricating oils withfurfural, Chlorex (B,B'-dichlorodiethylether), 50 nitrobenzene, Phenol, cresol, etc. may be employed. These extracts maybe employed, in accordance about 1 to 30% and even higher if desired but preferably from about 2 to about 10%. Such extracts are obtained in well known processes for solvent extraction which need not be described in detail; however, it should be noted that such extracts comprises ordinarily undesirable components of lubricating oils, heater oils, gas oils,

etc., for example, aromatics and/or polynuclear naphthenic compounds. Phenol and Chlorex extracts are preferred for this use.

{In nve-months storage of 4 025 samples during period from June to November. H r j are likewise useful.

Other extracts of herewith, in an amount of from employed) but that such sulfur is not included within the foregoing limits and is ordinarily not effective for purposes of imparting E.P. properties. I

Chlorinated compounds of various types are employed in extreme pressure lubricants. For example, products obtained by chlorinating paraflin wax or olefinic hydrocarbons have been found to be particularly useful. Individually chlorinated aliphatic compounds such as hexachlorethane, heptachlorpropane, octachlorhutane, etc. Reference'is made to US. 2,178,513 which sets forth a substantial number of halogenated 'organic ring compounds which are useful inextreme pressure lubricants. Such materials may be employed in accordance with the present invention. US. 2,276,341 discloses large numbers of chlorinated hydrocarbons and other chlorinated organic materials useful in extreme pressure oils. Thesealso maybe employed in accordance herewith. Chlorine-containing constituents are employed in extreme pressure lubricants and are useful in accordanceherewith in anamount sufficient to afford a total chlorine content in the lubricant of from about 0.3% to about 8% and preferably about 1% to 3%. Materials containing both sulfur and chlorinated 'materials, i.e. sulfochlorinated unsaturated compound, particularly a hydrocarbon, may be used. Just as the sulfur containing organic derivatives were referred to above as sulfur containing E.P., additives'so too will'the chlorine containing materials be referred to as chlorine containing El; additives.

In addition to the sulfurized and chlorinated materials and the lead naphthenate disclosed hereinabove, it should be understood that lubricants containing the same may also have added thereto typical lubricating oil additives such as antioxidants, oiliness agents, corrosion inhibitors, detergents, etc. Phosphorus-containing compounds may also be employed.- A particularly useful phosphoruscontaining material is that resulting from the treatment of a hydrocarbon, e.g. an olefin polymer, with a phosphorus sulfide. Other phosphorus-containing compounds, useful in lubricants of this kind, may also be used.

Percentages recited herein and in the appended claims are by Weight unless otherwise indicated.

Having thus described my invention what I claim as novel and desire to protect by Letters Patent is as follows:

1. An improved extreme pressure lubricant suitable for use under hypoid gear operating pressures comprising a major amount of a mineral lubricating oil, an effective amount of lead naphthenate in the range of from about 1.5% to about an effective amount of a sulfurcontaining organic extreme pressure agent in the range aifording from about 0.2% to about 3.0% sulfur, an amount of a chlorine-containing hydrocarbon extreme pressure agent in the range aifording from about 0.3% to about 8% chlorine and from about 1% to about 10% of oleic acid.

2. The composition of claim 1 wherein the sulfurcoutaining organic extreme pressure agent is a sulfurized sperm oil.

3. An improved extreme pressure lubricant suitable for use under hypoid gear operating pressures comprising a major amount of a mineral lubricating oil, an efiective amount of lead naphthenate in the range of from about 1.5% to about 10%, an effective amount of a sulfurcontaining organic extreme pressure agent in the range atfording from about 0.2% to about 3.0% sulfur, an amount of a chlorine-containing hydrocarbon extreme pressure agent in the range affording from about 0.3% to about 8% chlorine, from about 1% to about 10% of oleic acid, and from about 1% to about 10% of an alkyl phenol containing a total of from about 8 to about 12 carbon atoms in no more than two alkyl side chains, with no such side chain containing less than four carbon atoms.

4. The composition of claim 3 wherein the alkyl phenol is nonyl phenol.

5. The composition of claim 3 wherein the alkyl phenol is diamyl phenol.

References Cited in the file of this patent UNITED STATES PATENTS 1,319,129 Wells Oct. 21, 1919 2,031,930 Buc Feb. 25, 1936 2,031,986 Stratford et a1. Feb. 25, 1936 2,134,554 Grobel Oct. 25, 1938 2,322,209 Prutton June 22, 1943 2,367,355 Kaufman et a1. Jan. 16, 1945 2,383,905 Zimmer et al. Aug. 28, 1945 2,388,083 Reswick Oct. 30, 1945 2,417,833 Lincoln et al Mar. 25, 1947 2,701,237 Sokol Feb. 1, 1955 2,720,491 Beretvas Oct. 11, 1955 2,726,209 Fainman Dec. 6, 1955 2,754,269 Wasson et al. July 10, 1956 2,759,893 Beretvas Aug. 21, 1956 OTHER REFERENCES Practical Selection of Improved Lubricants, by Sibley et al., Refiner and Natural Gasoline Manufacture, vol. 14, No. 11, November 1935, page 529, Gulf Pub. Co.

Claims (1)

1. AN IMPROVED EXTREME PRESSURE LUBRICANT SUITABLE FOR USE UNDER HYPOID EXTREME PRESSURE LUBRICANT SUITABLE A MAJOR AMOUNT OF A MINERAL LUBRICATING OIL, AN EFFECTIVE AMOUNT OF LEAD NAPHTHENATE IN THE RANGE OF FROM ABOUT 1.5% TO ABLUT 10%, AN EFFECTIVE AMOUNT OF A SULFURCONTAINING ORGANIC EXTREME PRESSURE AGENT IN THE RANGE AFFORDING FROM ABOUT 0.2% TO ABOUT 3.0% SULFUR, AN AMOUNT OF A CHLORINE-CONTAINING BYDROCARBON EXTREME PRESSURE AGENT IN THE RANGE AFFORDING FROM ABOUT 0.3% TO ABOUT 8% CHLORINE AND FROM ABOUT 1% TO ABOUT 10% OF OLEIC ACID.