US2991250A - Marine turbine lubrication - Google Patents

Description

United States Patent 2,991,250 MARINE TURBINE LUBRICATION John F. Socolofsky, Glassboro, N.J., assignor to Socony Mobil Oil Company, Inc., a corporation of New York No Drawing. Filed Mar. 28, 1957, Ser. No. 649,001 2 Claims. (Cl. 25246.7)

and other'parts of the systemwhere the temperature" is relatively low. These insoluble materials may settle out on governor parts, in bearing passages, in coolers, strainers and oil reservoirs where their accumulation can interfere with'the supply of oil to bearings and with governor operation. Likewise, severe rusting conditions are encountered due to contamination of the oil with water from leaking shaft seals, condensation of humid air in the oil reservoir and bearing pedestals, water leaks in oil coolers, etc. Rust formation, ofcourse, is extremely undesirable for several reasons. Thus, rust particles catalyze oxidation of the oil. Also, rust is abrasive and when carried by the oil to the bearings causes scratching and excessive wear. Furthermore, when carried into the small clearances of the governor mechanism, the rust can cause sluggish operation and even make the governor stick.

It has therefore, become the practice in the art to fortify marine turbine oils by the addition theretoof chemical additives which enable these oils to resist oxidation and furnish maximum protection against rusting. Antioxidants which have been used, for example, 'incl-ude: phenolic-type compounds, particularly alkylated phenols, such as 2,6-di-tertiary-butyl-4-methyl phenol, 2,4,6-tri-tertiary-butyl-phenol and the like; aryl amines, such as phenyl-alpha-naphthyl amine, butyl-alpha-naphthyl amine, etc.; and alkylated diphenyl amines, such as octyldiphenyl amine. v Likewise, a variety of anti-rust agents have been utilized in turbine oils. One class of such anti-rust agents are theproducts produced by first reacting a monocarboxylic acid with a polyalkylenepolyamine and then reacting the product so formed with an alkenyl succinic acid anhydride. This class of anti-rust agents and their manner ofpreparation are fully described in U.S. Patent No. 2,568,876, issued September 25, 1951, to R. V. White et al. As shown in that patent, the monocarboxylic acid is reacted With the polyalkylenepolyamine in a mole proportion varying between about 1 and about x-l to 1,

respectively, where x represents the number of nitrogen atoms in the polyalkylenepolyamine molecule. The alkenyl succinic acid anhydride is then reacted with the intermediate product in a molar proportion varying between about x1 and about 1 to 1, respectively; the sum of the number of moles of the monocarboxylic acid and of the alkenyl succinic acid anhydride reacted with each 'tinued under these conditions for three hours. .ti'o'n product had an N.N. of 56.6. The product conice Five hundred and sixty-four grams (2.0 moles) of distilled oleic acid and 219 grams (1.5 moles) of triethylenetetramine were placed in a S-necked, 2-liter, roundbottomed flask provided witha stirring device, a thermometer and a reflux take-off trap. The trap was filled with benzene and the reactants were heated with stirring to 142 C. "About 40 ml. of benzene was added to the reaction mixture and reflux was maintained for ten hours with the flask contents at a temperature of 145 C. A total of 58 ml. of an aqueous layer was collected in the take-off trap. Benzene was removed from the reaction product by the gradual reduction in pressure to to 200 mm. Hg at a flask temperature of C. to C. The intermediate product so produced had a neutralization number (mg. KOH per gram of sample) of 4.2 and an average molecular weight of 484.

Sixty-three gramsof tetrapropenyl succinic acid anhydride having a neutralization number of (0.214

. 'mole) and 45 grams (0.093 mole) of the above intermediate product, together with 106 grams of diluent oil '(a conventional 100 sec. at 100 F. parafiin oil) were charged to a 3-necked, round-bottomed flask provided with a stirring device, a thermometer and an outlet tube which in turn was connected to a manometer, a Dry-Ice trap and a vacuum pump. The flask contents were heated 'with stirring to 100 C. and the pressure was gradually reduced to 50 mm. of mercury. The reaction was con- The reactained about 50%, by

agent. a

For some time oils fortified with antioxidant and antirust agents have been used successfully for the lubrication of marine turbines and their reduction gears. However,' with the development of smaller reduction gear sets and consequent heavier loading of gear teeth,,,these'oils have been found to be inadequate in that the lubricant film is unable to withstand the, high gear pressures and is ruptured. As a result, scufiing and scoring has occurred which reduces the service life and efliciency of the gears. The art has, therefore, sought to improve the load-carrying ability of turbine oils. Initially, it appeared that this could be accomplished simply by incorporating in the oil any one of a number of additives known to provide extreme pressure characteristics in lubricating oil. It was found, however, that although such additives did increase the load-carrying capacity of the oil, they also reduced the antioxidant and anti-rust characteristics of the oil to an intolerable degree. It, therefore, became a problem in the art to provide an additive which would not only provide extreme pressure properties in the turbine oil, but which at the same time would preserve the necessary high antioxidant and anti-rust characteristics of the oil. The present invention is concerned with the provision of such an additive. 'It is, therefore, an object of this invention to provide a marine turbine oil composition which possesses not only excellent antioxidant and anti-rust stability, but which also is capable of maintaining a lubricating film under the extreme pres: sures encountered in the turbine reduction gears. Other and further objects will become apparent from the following description of the invention.

In accordance with this invention, the above object is weight, of theactive anti-rust accomplished by the addition to the turbine oil of a small mole of the polyalkylenepolyamine being no greater than x. A specific product of this type is one prepared from oleic acid, triethylenetetramine and tetrapropenyl succinic acid anhydride, the preparation of which is' illustrated by the following example.

amount of tris-(Z-chloropropyl)-thionophosphate.

As far as is known, tris-(2-chloropropyl)-thionophosphate has not been proposed heretofore as an extreme pressure agent for lubricating oils. Accordingly, it is considered that the present invention embraces the use Reissued July 4, 1961 of this material as an extreme pressure agent, not only in turbine oils, but in lubricating oils in general. The ability of tris-(Z-chloropropyl)-thionophosphate as an extreme pressure additive and particularly its unique ability as an extreme pressure additive for use in turbine oils in comparison with a number of compounds heretofore recognized in the art as extreme pressure additives is illustrated by the data presented in Table I. This table shows the results of antioxidant, anti-rust and extreme pressure tests conducted on a typical turbine oil composition containing the usual amounts of antioxidant and anti-rust additives and on this same turbine oil composition having added thereto (a) diiferent known extreme The amount of tris-(Z-chloropropyl)-thionophosphate to be used as an extreme pressure agent in lubricating oils, including oxidation and rust-inhibited turbine oils, will range generally from about 0.25% to about 5.0%, the usual amount being from 1.0% to about 3.0%. Turbine oils in which the tris-(2-chloropropy1)-thionophosphate is employed may suitably contain from about 0.05 to about 2.0%, by weight, of antioxidant and from about 0.01% to about 1%, by weight, of anti-rust agent.

The oil compositions contemplated herein may also contain minor amounts of other additives, designed to improve the properties thereof in other respects, such as V.I. improvers, pour depressants, defoamants, etc.

Table l Additive Tris-(Q-chloropropyl)-thionophosphate.. Tetrabutylthiuram disulfide.

Tris-(B-chloroethy1)phosphite Dibenzyl disulfide Chlorokerosene Isopropyl Xanthate Zinc dithiophosphate Chlorinated paraflin wax Cl) 2 Benzothiazyl N,N diethyl thiocarbamyl sulfide. Load Tests:

SAE (p.s.i.) Timken (1bs.) Copper Strip Corrosion Test (A.S.T.M.

D 130; 3 Hr. 212 F.):

Tarmsh Rust Test: (A.S.T.M., D-943):

500 HL-NN (2)Mod. (1)Slt... (1)Slt (1)S1t.. (3) Dark.

. Henvy Moderate- Moderate.- None..

0.15 0.15 0.35 0.45 Heavy Moderate.. Moderate Moderate..

1 About one-half of iron coil disintegrated. 9 About three-quarters of iron coll disintegrated.

pressure additives and (b) tris-(Z-chloropropyD-thioncphosphate.

The turbine oil used as the base oil in all of the tests was a 400" SUV at 100 F., solvent-refined Mid-Continent oil containing 0.25% of 2,6-ditertiary butyl paracresol, a commercial antioxidant additive and 0.1% of an anti-rust agent prepared from oleic acid, triethylenetetramine and tetrapropenyl succinic acid anhydride after the fashion of Example I, hereinabove.

The procedures employed for the various tests were as follows:

(1) The SAE test was conducted according to CRC Method L-17-545 using a main shaft speed of 500 r.p.m. (CRC Handbook, 1946 edition, pages 458 to 462).

(2) The Timken test was conducted according to CRC Method L-18-545 (CRC Handbook, 1946 edition, pages 462 to 466).

(3) The copper strip corrosion test procedure was that of A.S.T.M. Method' D-130 (A.S.T.M. Standards on Petroleum Products and Lubricants. November 1952, pages 81 to 84).

(4) The rust test procedure was that of A.S.T.M. Test Method D-943 (A.S.T.M. Standards on Petroleum Products and Lubricants, November 1954, pages 418 to 422).

The results of the various tests are presented in Table I. It will be seen from the table that while all the blends show good load-carrying ability, blends Nos. 2 to 6 containing the various commercial extreme pressure addition agents and combinations were corrosive to either copper or steel or both. In comparison, blend No. 1 prepared with tris-(Z-chloropropyl)-thionophospliate gave complete protection against oxidation and rust. Of the various agents added to' provide load-carrying ability to the turbine oil, therefore, only the tris-(Z-chloroprbpyl) -thion0- phosphate successfully preserved the antioxidant and antir'ust characteristics of the oil. A

Having now fully described the invention, what is claimed to be new and useful and desired to be secured by Letters Patent is:

l. A method of lubricating a marine turbine and the associated reduction gears which comprises applying to the relatively moving parts thereof a composition comprising a major proportion of mineral lubricating oil, a minor proportion, from about 0.05% to about 2%, by weight, of a phenolic antioxidant, a minor proportion, from about 0.01% to about 1%, by weight, of an antirust agent consisting of a reaction product obtained by reacting a monocarboxylic acid with a polyalkylenepolyamine having one more nitrogen atom per molecule than there are alkylene groups in the molecule, in a molar proportion varying between about 1 and about x-l to 1, respectively, wherein x represents the number of nitrogen atoms in the polyalkylenepolyamine molecule, to produce an intermediate product, and reacting an alkenyl succinic acid anhydride with said intermediate product, in a molar proportion varying between about x-l and about 1 to 1, respectively; the sum of the number of moles of said monocarboxylic acid and of said alkenyl succinic acid anhydride reacted with each mole of said' polyalkylenepolyamine being no greater than x, and a minor proportion, from about 0.25% to about 5.0%, by weight, of tris-(2-chloropropyl)-thionophoshate. p 2. A method of lubricating a marine turbine and the associated reduction gears which comprises applying to the relatively moving parts thereof a composition comprising a major proportion of mineral lubricating oil, a minor proportion, from about 0.05 to about 2%, by weight, of a 2,6-ditertiary butyl paracresol, a minor proportion, from about 0.01% to about 1%, by weight, of a reaction product formed by reacting about one and one-third molar proportions of oleic acid with 1 molar proportion of triethylenetetramine to rform an intermediate product and then reacting about 1 molar proportion of the intermediate product with 2 molar proportions of tetrapropenyl succinic acid anhydride and a minor proportion, from about 0.25% to about 5%, by weight, of tn's-(2-ch1oropropy1)-thionophosphate.

References Cited in the file of this patent UNITED STATES PATENTS Prutton Oct. 31, 1939 Kavanagh Mar. 28, 1944 2 White Sept. 25, 1951 Smith Nov. 1, 1955 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 2,991,250 July 4 1961 John F, So c olof'sky hat error appears in ,the above nuInbredpat- It is hereby certified t F that the said Letters Patent should read as entrequiring correction and corrected below In the heading to columns 1 and 2 upper right-hand g q portion after the patent number for "Reissue July 4 1961'" read Patented July 4 1961 a (SEAL) Attest:

ERNEST W. sWIDE Attesting Officer I DAVID L. LADD Commissioner of Patents

Claims (1)

1. A METHOD OF LUBRICATING A MARINE TURBINE AND THE ASSOCIATED REDUCTION GEARS WHICH COMPRISES APPLYING TO THE RELATIVELY MOVING PARTS THEREOF A COMPOSITION COMPRISING A MAJOR PROPORTION OF MINERAL LUBRICATING OIL, A MINOR PROPORTION, FROM ABOUT 0.05% TO ABOUT 2%, BY WEIGHT, OF A PHENOLIC ANTIOXIDANT, A MINOR PROPORTION, FROM ABOUT 0.01% TO ABOUT 1%, BY WEIGHT, OF AN ANTIRUST AGENT CONSISTING OF A REACTION PRODUCT OBTAINED BY REACTING A MONOCARBOXYLIC ACID WITH A POLYALKYLENEPOLYAMINE HAVING ONE MORE NITROGEN ATOM PER MOLECULE THAN THERE ARE ALKYLENE GROUPS IN THE MOLECULE, IN A MOLAR PROPORTION VARYING BETWEEN ABOUT 1 AND ABOUT X-1 TO 1, RESPECTIVELY, WHEREIN X REPRESENTS THE NUMBER OF NITROGEN ATOMS IN THE POLYALKYLENEPOLYAMINE MOLECULE, TO PRODUCE AN INTERMEDIATE PRODUCT, AND REACTING AN ALKENYL SUCCINIC ACID ANHYDRIDE WITH SAID INTERMEDIATE PRODUCT, IN A MOLAR PROPORTION VARYING BETWEEN ABOUT X-1 AND ABOUT 1 TO 1, RESPECTIVELY, THE SUM OF THE NUMBER OF MOLES OF SAID MONOCARBOXYLIC ACID AND OF SAID ALKENYL SUCCINIC ACID ANHYDRIDE REACTED WITH EACH MOLE OF SAID POLYALKYLENEPOLYAMINE BEING NO GREATER THAN X, AND A MINOR PROPORTION, FROM ABOUT 0.25% TO ABOUT 5.0%, BY WEIGHT, OF TRIS-(2-CHLOROPROPYL)-THIONOPHOSPHATE.