US 3919096 A
The extreme pressure property of a lubricant is remarkably improved by adding to the lubricant a mixture of sulfurized alkylene monomer, dihydrocarbyl phosphonate and benzotriazole.
Description (OCR text may contain errors)
United States Patent 11 Olszewski [451 Nov. 11,1975
[ COMBINATION OF BENZOTRIAZOLE WITH OTHER MATERIALS AS EP AGENTS FOR LUBRICANTS  Inventor: William Frank Olszewski, Cherry Hill. NJ.
 Assignee: Mobil Oil Corporation, New, York,
 Filed: Oct. 29, 1974 211 Appl. No.: 518,669
UNITED STATES PATENTS 3.553.131 l/l97l l-lepplewhite et al 252/46.7
Hendrick son 252/46] Nebzydoski et al. 252/46] ll/l97l ll/l974 Primary E.\'uminerDelbert E. Gantz Assistant Exmniner-I. Vaughn Attorney, Agent, or Firm-Charles A. Huggett; Raymond W. Barclay; Claude E. Setliff  ABSTRACT The extreme pressure property of a lubricant is remarkably improved by adding to the lubricant a mixture of sulfurized alkylene monomer. dihydrocarbyl phosphonate and benzotriazole.
9 Claims, No Drawings COMBINATION OF BENZOTRIAZOLE WITH OTHER MATERIALS AS EP AGENTS FOR LUBRICANTS BACKGROUND OF THE INVENTION lubricants containing a mixture ofa sulfurized alkylene monomer, dihydrocarbyl phosphonate and benzotriazole.
2. Summary of the Prior Art U.S. Pat. No. 3,115,465 deals with combinations of phosphorus compounds and hindered phenols for inhibition of oxidation of organic compositions. U.S. Pat. No. 3,471,404 teaches a process for making sulfurized olefins and discloses them to be useful as loan carrying additives. It is known, in accordance with U.S. Pat. No. 3,652,41 1 that benzotriazole can be mixed with other materials such as a phenol, an amine, a polyhydroxyquinone, an amine salt and an organic phosphite to produce an antioxidant for polyglycol base lubricants. Further, U.S. Pat. No. 3,597;353 teaches the use of benzotriazole as a copper 'deactivator in an anti-freeze solution. However, it will be apparent fromthe remaining disclosure that these patents do not disclose or suggest the inventiondisclosed and claimed herein.
SUMMARY OF THE INVENTION The invention provides a lubricant composition comprising a mineral or a synthetic hydrocarbon or synthetic ester baselubricant'and an additive mixture comprising (1) a dihydrocarbyl phosphonate having from 1 to carbon atoms,(2 a sulfurized'alkylene monomer, wherein alkylene has from 2 to 6 carbon atoms and benzotriazole? DESCRIPTION OF SPECIFIC EMBODIMENTS The di(organo)phosphonates used in this invention have the structure wherein R and R are individually alkyl or alkenyl from I to 20 carbon atoms and may have the same number of carbon atoms or a different number. The phosphonates used in this invention may be produced by known methods of synthesis The second co-additivefor the compositions of this invention may be designated as an active sulfur compound. The compounds of this class consist of sulfurized hydrocarbon monomers having up to 65% sulfur. Encompassed in this class are those compounds wherein the sulfur is loosely-bound, and the non-corrosive or firmly-bound sulfur compounds.
The preferred example of the sulfur additive used in this invention are the polysulfurized alkylene hydrocarbon monomers, particularly those derived from olefins having from 2 to 6 carbon atoms. Suitable examples of such organic polysulfides are the polysulfides of ethylene, propylene, butylene, amylene, and the like. Sulfurized alkylene compounds, such as sulfurized isobutylene containing from about 30% to about 65% sulfur,
2 and preferably from 35% to 50% sulfur, are used herein. g
The preferred sulfurized alkylene compounds may be prepared by known means. One of the suitable routes for obtaining this additive is through the reaction of a mercaptan with a sulfur halide to form an organosulfenyl halide. This halide is then reacted with an olefin, whereby the sulfur atoms are added to the carbon atoms on either side of the double bond. The product so formed is a thioethyl halide. lFurther reaction of this compound with a sulfur-containing metal or ammonium salt, such as a metal sulfide, adds another sulfur atom to the product. Another means of obtaining polysulfurized alkylene compounds involves reacting the sulfur halide, such as sulfur monocliloride, with an excess of olefin, such as isobutylene. This product is reacted with an alkali metal sulfide: in the presence of free sulfur. The resulting product is then neutralized with an inorganic base, such as sodium hydroxide. See U.S. Pat. No. 3,471,404. In these reactions, the use of butylene as the olefin is preferred. The products contain a high percent of sulfur which has been found to be non-corrosive to metal parts of engines.
The compositions of this invention are effective in fluid compositions in which the lubricant base is a pctroleum product, suchas a mineral lubricating oil, or a synthetic fluid. Such synthetic oils as hydrocarbon fluids derived from either long chain alkanes or olefin polymers, ester lubricants obtained from polyhydric alcohols and monocarboxylic acids or monohydric alcohols and dicarboxylic acids may be used as the base medium for this invention.
The additive concentration may vary from about 0.02 to about 10.0 7c for each of the phosphonate and sulfurized alkylene additives. Preferably,the range is from 0.10 to 4.0 by weight of lubricant. Optimum performance characteristics are evidenced when the fluid composition contains from about 0.02 to 0.50 and especially 0.10 phosphorus and from about 0.50 to 10.0 and especially 2.0 sulfur.
The third ingredient of the additive mixture is benzotriazole, and it is used to the extent of from about 0.005% to about 1.0% of the lubricant. Benzotriazole has an entirely unexpected effect on the combination of phosphonate and sulfurized hydrocarbon. As will be demonstrated below, when known E.P. agents are added to base oil containing the phosphonate and sulfurized hydrocarbon, no increase in EP properties (over those shown by the additives already present) is noted.
EVALUATION OF INVENTION The base oil used was an SAE mineral oil lubricant containing an additive package comprising dibutyl phosphonate [(C H O) POH] and sulfurized isobutylene containing about 45% sulfur (prepared substantially in accordance with U.S. Pat. No. 3,471,404). To this lubricant composition were added several known E.P. agents in varying concentrations. Then benzotriazole was added in place of the known E.P. agents. The resulting composition, in each case, was tested in the Timken Load Test.
This test is a known test used to determine the load carrying properties of additives in lubricating oil compositions. The test is conducted by placing a steel test cup on a shaft which can be rotated at 800 rpm. Just below the cup and in contact with it is a small stationary steel block. A load is placed on these parts by 3 means of a lever arm which pushes the block upwards against the rotating cup, which acts as a roller bearing, while the lubricant flows between the two surfaces. The load is gradually increased at 10-minute intervals until failure occurs. Failure is determined by visual inspection during the running period. Load usually varies from to 80 pounds. The load for a pass result is the highest load which does not produce scoring of the contacting test surfaces.
The table below summarizes the results.
TIM KEN TEST Composition Pass Load, lbs.
Base oil 45 Base oil l.0'7( sulfurized polyisobutylene 45 Base oil l.0% sulfurized sperm oil substitute* 45 Base oil l.()% chlorinated wax (40% chlorine) 40 Base oil 0.5% octyl acid phosphonate 40 Base oil 0.3% benzotriazole 70 Base oil 0.5% benzotriazole 70 Base oil 0.005% benzotriazole 60 *sulfurized vegetable oil containing sulfur It is apparent from this data that there was either no change in the pass load or such load actually decreased when conventional E.P. agents were added to the base oil (containing phosphonate and sulfurized hydrocarbon). Apparent also is the fact that when as little as 0.005% benzotriazole was added to the same system, there was an increase of more than l5 pounds at the 0.005% concentration and more than 25 pounds at the 0.05% and 0.3% levels. Such a result was entirely unexpected.
The above table is presented merely for the purposes of illustration and is not intended to limit the scope of the invention.
l. A lubricant composition containing a major proportion of a mineral oil, a synthetic hydrocarbon fluid, a synthetic ester lubricating oil or a grease made therefrom and an extreme pressure amount of the additive mixture comprising a dihydrocarbyl phosphonate. a sulfurized alkylene monomer and benzotriazole.
2. The composition of claim I wherein the phosphonate has the formula wherein R and R are the same or different and are individually selected from the group consisting of alkyl and alkylene having from I to 20 carbon atoms.
3. The composition of claim 1 wherein the sulfurized alkylene is a sulfurized olefin having 2 to 6 carbon atoms.
4. The composition of claim 3 wherein the sulfurized olefin contains from about 30 to about sulfur.
5. The composition of claim 4 wherein the sulfur content is from about 30% to about 50%.
6. The composition of claim 2 wherein R and R are butyl.
7. The composition of claim 3 wherein the sulfurized olefin is sulfurized isobutylene.
8. The composition of claim 1 wherein the lubricant is a mineral lubricating oil 9. The composition of claim 1 wherein the lubricant is a mineral lubricating oil, the dihydrocarbyl phosphonate is dibutyl phosphonate and the sulfurized alkylene monomer is sulfurized isobutylene containing about 45% sulfur.
UNITED STATES PATENT AND TRADEMARK OFFICE CERTEFICATE OF CORRECTION PATENT NO. 3,919,096
DATED 1 November ll, 1975 IN 1 WILLIAM FRANK oLsZEwsKI It is certified that error appears in the above-identified patent and that said Letters Patent 0 are hereby corrected as shown below:
Column 1, line 18 "loan" should read -load-.
H H Column 1, llne A5 I RO\P/O a B0 H should read RO O.
R'6 H Column 1, line 49 "R and R" should read R and R'-. Column 1, line 10 "RO O" P & RO H should read -RO o--.
R'O H Column i, line 15 "R and R" should read -R and R'. Column l, line 26 "R and B" should read R and R'-. Column l, line 31 Place period at end of the word "Oil".
Signed and Sealed this eighteenth Day of May 1976 [SEAL] Atresr:
RUTH C. MASON C. MARSHALL DANN T Amuing Officer (ommissimu'r of Patents and Trademark