US2993859A - Synergistic extreme pressure agent and lubricant composition - Google Patents

Description

United States Patent P 2,993,859 SYNERGISTIC EXTREME PRESSURE AGENT AND LUBRICANT COMPOSITION Harold J. Watson, Danville, Va., assignor to Texaco Inc., a corporation of Delaware No Drawing. Filed July 29, 1958, Ser. No. 751,607 7 Claims. (Cl. 252-495) This invention relates to an improved lubricating composition containing a combination of additives which exhibits synergistic extreme pressure properties. More particularly, this invention relates to lubricating oils containing a mixture of a chlorinated high molecular Weight hydrocarbon and a polyhalogenated organic phosphonate.

There is an ever increasing need for the improvement of the extreme pressure properties of lubricating oils used in heavy high speed machinery. This is particularly true for the lubrication of newly developed jet turbine and marine turbine engines. The present invention defines an additive combination possessing synergistic extreme pressure action which is particularly useful in the formulation of jet engine and marine engine turbine oils.

The synergistic extreme pressure additive combination of this invention consists essentially of a chlorinated paraflin wax and a di[halo (C -C alkyl] halo (C -C alkyl phosphonate in a weight ratio of from 4 to 16 parts of chlorinated paraffin wax per part of polyhalo-organic phosphonate.

The lubricating composition of the invention comprises from 0.5 to 5.0 weight percent chlorinated parafiin wax and 0.05 to 1.5 weight percent di[h alo (C -C alkyl] halo (C -C alkyl phosphonate. The small concentration of polyhalo-organic phosphonate which has some efiect on the extreme pressure properties of the oil alone causes a significant and unexpected improvement of the extreme pressure properties exhibited by oil containing chlorinated parafiin Wax which is also a known extreme pressure agent.

The chlorinated paraffin wax employed in the present lubricant is one having a high content of combined chlorine, the major proportion of which is in a so-called active state. The chlorine content of this additive is between 35 and 45 weight percent of the compound. For example, a preferred material of this character has a total combined chlorine content of about 40-45 percent with an active chlorine content of about 29-34 percent. Preferably, the chlorinated parafiin wax contains a small proportion of an oil-soluble corrosion inhibitor of the type disclosed in US. Patent No. 2,298,638, which functions to neutralize the eitect of any decomposition of the chlorinated paraflin wax with the release of free chlorine. Phenoxy propylene oxide is used as a corrosion inhibitor of this type.

The concentration of the chlorinated parafiin wax in the lubricant composition of the invention falls between 0.5 and 5.0 weight percent of the total lubricant with concentrations between 1.0 and 3.0 weight percent usually being employed. It is significant that the desired level of extreme pressure activity is obtained with relatively low concentrations of chlorinated parafiin wax, which fact is directly attributable to the synergistic action of the polyhalo-organic phosphonate.

The di[halo (C1C4) y halo 1 4) alkyl phosphonate which is employed as a second component of the additive combination of this invention is preferably a di(fi-chloroethyl)ii-chloroethane phosphonate. Ex-

2,993,859 Patented July 25, 1961 amples of other phosphonates which are useful in this invention include:

di(chloromethyl) chloromethane phosphonate di(chloropropyl) chloropropane phosphonate di(chlorobutyl) chlorobutane phosphonate di(chloroethyl) ehloromethane phosphonate di(chloroethyl) chloropropane phosphonate di(bromoethyl) bromobutane phosphonate di(iodoethyl) iodoethane phosphonate di(bromobutyl) bromobutane phosphonate di(fiuoroethyl) fluoroethane phosphonate Only small concentrations of the di(haloalkyl) haloalkyl phosphonate are necessary to exert their synergistic action in combination with the chlorinated parafiin wax. The concentration of phosphonate in the lubricating oil is usually from 0.05 to 1.5 weight percent and preferably about 0.1 to 0.5 percent.

The weight ratio of chlorinated parafiin wax to polyha-lo-organic phosphonate in the synergistic extreme pressure additive of the invention expressed independently of the mineral lubricating oil is 4 to 16 and preferably 6 to 10 parts of chlorinated paraffin wax per part of di- (haloalkyl) haloalkyl phosphonate.

The base oils with which the novel extreme pressure additive of the invention is used are hydrocarbon lubricating oils, synthetic lubricating oils and mixtures thereof. The hydrocarbon oils include mineral, vegetable and animal oils, but particularly, hydrocarbon mineral oils which could be parafiin base, naphthene base or residual type oils. The viscosity range of the mineral lubricating base oil is between and 1000 SUS at F. The base oils usually have a flash point between 320 and 520 F., a pour point within the range of +20 to -50 F. and a viscosity index between 10 and 120.

Particularly preferred oils for marine turbine lubricants are parafi'in base oils which have been solvent dewaxed and clay percolated and which have an SUS viscosity at 100 F. between 300 and 600.

The synthetic lubricating bases include high molecular weight polyalkylenes and high molecular weight, high boiling liquid aliphatic dicarboxylic acid esters which possess excellent viscosity-temperature relationships and lubricating properties, and are finding ever increasing utilization in lube oils and greases adapted for high and low temperature lubrication. Examples of the ester class of synthetic lubricating bases are the diesters of acids such as sebacic, adipic, azelaic, alkenyl-succinic, etc; specific examples of these diesters are di-Z-ethylhexyl sebacate, di-Z-ethylhexyl 'azelate, di-Z-ethylhexyl adipate, di-namyl sebacate, di-Z-ethylhexyl-n-dodecyl succinate, di-2- ethoxyethyl sebacate, di-2-methoxy-2-ethoxyethyl sebacate (the methyl Carbitol diester), di-2-ethyl-2-n butoxyethyl sebacate (the Z-ethylbutyl Cellosolve diester), di-2- butoxyethyl azelate (the n-butyl Cellosolve diester) and di-2-n-butoxy-Z-ethoxyethyl-n-octyl succinate (the nbutyl Carbitol diester).

A preferred high molecular weight polyalkylene is polybutene having a molecular weight range of from 500- 1500.

Polyester lubricants formed by a reaction of an aliphatic dicarboxylic acid of the type described above, a glycol and a monofunctional aliphatic monohydroxy alcohol or an aliphatic monocarboxylic acid in specified mole ratios are also employed as the synthetic lubricating base in the compositions of this invention; polyesters of this type are described in US. 2,628,974. Polyesters formed by reaction of a mixture containing specified amounts of dipropylene glycol, sebacic acid and 2-ethylhexanoic acid and of a mixture containing adipic acid, diethylene glycol and Z-ethylhexanoic acid illustrate this class of synthetic polyester lubricating bases.

Polyalkylene ethers as illustrated by polyglycols are also used as the lubricating base in the compositions of this invention. Polyethylene glycol, polypropylene glycol, polybutylene glycols and mixed poyethylene-polypropylene glycols are examples of this class of synthetic lubricating bases.

The sulfur analogs of the above-described diesters, polyesters and polyalkylene ethers are also used in the formulation of the lubricating compositions of this invention. Dithioesters are exemplified by di-Z-ethylhexyl thiosebacate and di-n-octyl thioadipate; polyethylene thioglycol is an example of the sulfur analogs of the polyalkylene glycols; sulfur analogs of the poyesters are exemplified by the reaction product of adipic acid, thioglycol and Z-ethylhexyl mercaptan.

Alkyl-substituted phenols are usually incorporated in the lubricants of the invention as anti-oxidants. The preferred and most commonly used alkyl phenol anti-oxidant is 2,6-di-tertiary butyl-4-methylphenol which is commercially available from a number of sources. Examples of other phenolic type anti-oxidants which may be employed are 2,6-di-tertiary butylphenol; 2,6-di-tertiary amyl-4- methylphenol; and 2,6-di-isopropyl 4 methylphenol. Hindered phenols of this type are employed in concentrations between 0.1 and 1.0 weight percent.

Although hindered phenol type anti-oxidants are the most widely used anti-oxidants in the lubricant compositions of the invention, aryl-substituted amine anti-oxidants such as phenylnaphthylamine, phenylene diamine, and diphenyl-amine are also used in lubricants in conjunction with the synergistic extreme pressure additive combination of the invention. The amine anti'oxidants are employed in the same concentrations as the hindered phenol antioxidant.

The anti-rust compounds which are particularly necessary for marine turbine lubricants are the alkyl substituted aliphatic dicarboxylic acids such as alkenyl-succinic acids, alkyl-maleic acids and alkyl-succinic acids. These aliphatic-substituted dicarboxylic acids are usually used in conjunction with a minor portion of an acid ester of an alkyl phosphate. A mixture of monoand dilauryl esters of phosphoric acid is widely used in conjunction with an aliphatic substituted aliphatic dicarboxylic acid as an anti-rust additive mixture. A detailed description of this additive mixture is found in US. Patent 2,452,321, which issued Oct. 26, 1948 to John A. Patterson and Herman D. Kluge and which is assigned to The Texas Company. The dicarboxylic acid is usually employed in a concentration between 0.01 and 0.1 weight percent and the alkyl phosphate in a concentration between 0.0001 and 0.03 weight percent.

Organic silicones are normally incorporated in the lubricants of the invention to impart anti-foam properties thereto. The silicones are usually of the dialkyl or mixed alkyl-aryl silicone type. Dimethyl silicone is normally employed as the anti-foam agent. The silicone is incorporated in the lubricant by means of a kerosene concentrate containing 5 to weight percent silicone. A very satisfactory anti-foam agent is a kerosene concentrate containing 10 weight percent dimethyl silicone. The kerosene concentrate is employed in an amount sutficient to provide a silicone polymer concentration of from 50 to 250 parts per million based on the total lubricant composition.

The synergistic extreme pressure properties of an additive mixture of chlorinated paraffin wax and di (,8 chloroethyl) 5 chloroethane phosphonate was demonstrated in a base oil comprising mineral lubricating oil; 0.3 weight percent 2,6-dit-butyl-4-methylphenol; 0.033 weight percent of an anti-rust concentrate comprising 45 percent of a C alkenyl succinic acid in which the alkenyl group is propylene tetramer, 10 percent of a mixture of monoand dilauryl phosphoric acid esters and 45 percent diluent oil; and about 100 parts per million of an anti-foam concentrate comprising 10 weight percent dimethyl silicone in kerosene. The mineral lubricating oil was a furfural refined, acid-treated, clay-contacted, solvent dewaxed and clay percolated paraflin base distillate having an SUS viscosity at 100 F. of about 500, a pour of l0 F. maximum, a flash of 380 F. minimum and a viscosity index of about 90.

The testing of the EP properties in the combination of additives of this invention was performed using the test procedure and apparatus of the High Speed Gear Scuff Test. This test is intended for the evaluation of the scufflirnited load-carrying ability of those lubricants used in reduction and accessory drives of turbo-jet and turbo-prop engines. The method of test provides for the running of two spur gears in a Pratt and Whitney Gear and Lubricant Tester (also termed the Ryder Gear Tester). The face width of the driven gear was 0.937 inch and the face width of the driving gear was 0.25 inch. The dynamometer speed of the gear tester was put up to 4600 rpm. and a loading pressure of 2.5 p.s.i. applied. After running for 15 minutes, the tester was shut down and the driving gear removed and an estimate of the percentage of tooth area scuffed on each tooth of that gear was made. The gear was replaced and the above procedure continuously repeated using a higher loading pressure at each repetition until 22.5 percent of the total tooth face area on the driving gear had been sculfed, the load corresponding to this point being considered the scuff load. The loading pressures to be successively used were as follows: 3.5, 5, 7.5, 10,125, 15, 17.5, 20, 25, 30, 35, 40, 45, 50, 60, 70 and 80 p.s.i. A tooth load conversion factor of 18.5 pounds, which was a constant calculated from measured data from the Tester, was multiplied by the loading pressure at the scuif load and the result divided by the width of the driving gear (0.25) to obtain the tooth load in pounds per inch.

In Table I there are presented data proving the synergistic extreme pressure action of a mixture of di(;8-chloroethyDfl-chloroethane phosphonate and chlorinated paraffin wax having a chlorine content of 40 percent.

TABLE I High speed gear test Run Additive (wt. percent) Load, lbsJ inch None 1, 410 2% chlorinated paraffin wax 3, 510 3% chlorinated paratlin wax 3, 500 0.25% di(fi-chloroethyDfichloroethanc phos- 2,

phonate. 2% chlorinated paraflin wax plus 0.25% di(fi 5, G00

chloroethyDB-chloroethane phosphonate.

The data in the foregoing table prove that mixtures of chlorinated paraifin wax and di(haloalkyl) haloalkyl phosphonate in the ratio disclosed possess a surprising synergistic extreme pressure action. 0.25 percent of di(fi-chloroethyl)fi-chlorethane phosphonate in the base oil can improve the ability of the lubricant to withstand a load to about 700 lbs. per inch over the base oil alone. However, when this same amount of additive is used in combination with 2 percent of the chlorinated parafiin wax the increase of the load is about 2150 lbs. per inch over the base oil containing just the 2 percent chlorinated paraflin wax. This is very significant in view of the fact that an additional one per cent of the chlorinated paraffin wax only raised the load carrying ability of the lubricant 50 lbs.

The EP additive combination of the invention was also tested in the Mean Hertz Load Test. The procedure and apparatus of this test is described in US. Patent 2,600,058.

In Table II following are shown data indicating the superiority of the additive combination in the Mean Hertz Load Test. The base oil is that described in connection with the test procedure of Table I.

TABLE II Mean Hertz load test Additive (wt. percent) Load, kg.

None 2% chlorinated paraffin wax 3% chlorinated paraffin wax 0.25% di(B-chloroethyDfl-chloroethane phosphonate.

2% chlorinated parafiin wax plus 0.25%

di(s-chloroethyDB-chloroethane phosphona e.

Again the data of the foregoing table proves that mixtures of chlorinated paraffin wax and the di(ha1oalkyl) haloalkyl phosphonate as described promote unexpected synergistic extreme presure activity. The addition of 0.25% di(B-chloroethyl)B-chloroethane phosphonate to the base oil increased its load carrying capacity kg. The addition of this same amount of the phosphonate to the base oil having 2 percent chlorinated paraffin wax therein increased the load carying ability of the base oil over 20 kg. Again, this is particularly significant in view of the fact that the additional 1 percent chlorinated parafiin wax was added to the base oil already containing 2 percent chlorinated parafiin wax increased the load carrying ability in this test procedure only 3 kg.

Obviously, many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

Iclaim:

1. A synergistic extreme pressure additive combination for lubricants consisting essentially of from 4 to 16 parts by weight of a chlorinated parafifin wax having a chlorine content of from about 35 to 45 percent by weight, and 1 part by weight of a di[halo (C C alkyl] halo (C -C alkyl phosphonate.

2. A synergistic extreme pressure additive combination for lubricants consisting essentially of from 4 to 16 parts by weight of a chlorinated paraflin wax having a total chlorine content of from 40 to 45 percent by weight, and

, phonate.

5. A mineral lubricating oil containing from 1 to 3 weight percent of a chlorinated parafiin wax having a total chlorine content of from 40 to weight percent, and from 0.1 to 0.5 weight percent of di(p-chloroethyl)flchloroethane phosphonate.

6. A mineral lubricating oil containing 0.1 to 1 weight percent of an alkyl-substituted phenol, from 0.01 to 0.1 weight percent of an aliphatic substituted aliphatic dicarboxylic acid, from 0.0001 to 0.03 weight percent of an alkyl phosphate, from to 250 parts per million of an organic silicone, from 0.5 to 5 weight percent of a chlorinated paraffin wax having a chlorine content of from 35 to 45 weight percent, and from 0.05 to 1.5 weight percent of a di[halo (C C alkyl] halo (C C alkyl phosphonate.

7. A mineral lubricating oil containing about 0.3 weight percent 2,6-ditertiary butyl-4methylphenol, about 0.033 weight percent of an anti-rust concentrate consisting of 45 percent of a C alkenyl succinic acid, 10 percent of a mixture of monoand dilauryl phosphoric acid esters and 45 percent diluent oil; about parts per million of dimethyl silicone, from 1 to 3 weight percent of a chlorinated parafiin wax having a total chlorine content of from 40 to 45 percent, and from 0.1 to 0.5 weight percent of di(,B-chloroethyl), B-chloroethane phosphonate.

References Cited in the file of this patent UNITED STATES PATENTS Re. 23,979 Harman et a1 Apr. 12, 1955 2,126,590 Valentine Aug. 9, 1938 2,174,019 Sullivan Sept. 26, 1939 2,452,319 Patterson et a1 Oct. 26, 1948 2,722,517 Smith et al Nov. 1, 1955 2,824,839 Templemann Feb. 25, 1958

Claims (2)

1. A SYNERGISTIC EXTREME PRESSURE ADDITIVE COMBINATION FOR LUBRICANTS CONSISTING ESSENTIALLY OF FROM 4 TO 16 PARTS BY WEIGHT OF A CHLORINATED PARAFFIN WAX HAVING A CHLORINE CONTENT OF FROM ABOUT 35 TO 45 PERCENT BY WEIGHT, AND 1 PART BY WEIGHT OF A DI(HALO (C1-C4) ALKYL) HALO (C1-C4) ALKYL PHOSPHONATE.

3. A LUBRICATING OIL CONTAINING FROM 0.5 TO 5 PERCENT BY WEIGHT OF A CHLORINATED PARAFFIN WAX HAVING A CHLORINE CONTENT OF FROM 35 TO 45 WEIGHT PERCENT, AND FROM 0.05 TO 1.5 WEIGHT PERCENT OF A DI(HALO (C1-C4) ALKYL) HALO (C1-C4) ALKYL PHOSPHONATE.