US2592497A

US2592497A - Extreme pressure lubricant

Info

Publication number: US2592497A
Application number: US124515A
Authority: US
Inventors: Walter E Waddey; Elmer B Cyphers
Original assignee: Standard Oil Development Co
Current assignee: Standard Oil Development Co
Priority date: 1949-10-29
Filing date: 1949-10-29
Publication date: 1952-04-08
Anticipated expiration: 1969-04-08
Also published as: GB668111A

Description

Patented Apr. 8, 1952 UNITED STATES PATENT OFFICE EXTREME PRESSURE LUBRICANT Oil Development Company, a

Delaware corporation of No Drawing. Application October 29, 19519, Serial No. 124,515

4 Claims. 1

This invention pertains to extreme pressure lubricants and compositions for imparting extreme pressure or load carrying properties to lubricating oils. The invention also pertains to a method for preparing extreme pressure agents which ample, certain machine elements such as the hy-' poid gears commonly used in automotive vehicles may be subjected at times to extremely heavy pressures of the order of hundreds of thousands of pounds per square inch of bearing surface. If the film of lubricating oil separating the opposed elements fails, that is, is squeezed from'between the opposed elements, as is likely to happen under such extremely high pressures, the surfaces of the opposed elements will contact each other directly. This direct contact of the metal surfaces generates high temperatures due to friction which causes metal seizure, excessive wear, and early surface failure.

It is also known in the art that extreme pressure additives containing active sulfur, phosphorus or chlorine alone or in combination when contained in the lubricant used are effective for preventing the excessive wear and early surface failure caused by the squeezing out of the protective oil film under heavy load conditions. The active sulfur, phosphorus, or chlorine react immediately with the unprotected metal surfaces at the high temperatures generated to form a protective metal sulfide, phosphide, or chloride film. This film serves temporarily as a lubricating medium until the normal oil film can be reestablished between the metal surfaces. Extreme pressure additives are, therefore, reactive with. the metals they lubricate, forming extremely, thin protective films thereon when the temperature rises due to the normal oil film failure.

It has been found, and is the subject of this invention, that excellent extreme pressure additives may be prepared by combining a phosphosulfurized fatty body with a halogenated nonvolatile organic compound.

Accordingly, it is the object of this invention to provide a new and useful extreme pressure additive for lubricating oils. A further object of this invention is to provide lubricating oil compositions which have excellent extreme pressure and load carrying properties.

Briefly stated, this invention comprises incorporating into a lubricating oil a mixture of a fatty body which has been treated with a phosphorus sulfide, and a halogenated non-volatile organic material. Although it is within the concept of this invention to use as one ingredient any oxidized fatty body combined with phosphorus sulfide, the preferred embodiment of the inventio is phospho-sulfurized degras. Degras, the dark brown grease from sheep wool, may be phospho-sulfurized by the procedure described below. The other constituent of the mixture combined with a lubricating oil to make the ex treme pressure lubricant of this invention is a halogenated non-volatile organic compound typified by chlorinated wax, chlorinated kerosene, chlorinated naphtha, chlorinated oil, or a chlorinated methyl ester of tall oil, the preferred embodiment of the invention being chlorinated wax.

The first mentioned constituent of the extreme pressure additive mixture, that is, the phosphosulfurized degras, may be made by reacting commercially available degras, a Wool oil extract, with about 10 to 40% by weight, preferably about 18 to 25% by weight, of phosphorus pentasulfide (Pass) at a temperature of between 275 F. and 350 F., preferably 300 F. It is convenient to carry out the reaction in solution, for example in a lubricating oil fraction, thereby obtaining an oil concentrate which may contain, say, about 30-70% of active ingredients. Degras has an oxygen content (by analysis) of 6 to 7%. An exothermic reaction occurs and generally a reaction time of an hour or slightly less is involved. The temperature is above the temperature of the thicphosphate formation and may be carried out without the introduction of any substantial amount of phosphorus into the. reaction product. However, if a lower temperature is used a thiophosphate may be formed. The phosphorus and oxygen-containing sludge may be removed. This reaction product, depending upon the proportion of ingredients and the temperature used. will contain from 4 to 13% sulfur, and from 0.5 to 3.9 7'2; phosphorus, on the basis of a 50% concentrate.

The chlorinated non-volatile organic material used as the second constituent of the extreme pressure additive mixture of this invention may be made by any of the methods known to the art. For example, chlorinatedwax may be made by bubbling chlorine or a chlorine containing gas through a meltedwax until it contains from about 35 to about 65% of chlorine. The same general procedure is used for chlorinating kerosene, aromatic heavy naphtha, a lubricating oil or other hydrocarbon which may be used as the second ingredient.

These two constituents are mixed together in varying proportions depending upon the amounts of chlorine, phosphorus, and sulfur that it is desired to incorporate into the lubricating oil. The percentage of the sulfurized degras product may vary between 2% by weight and 15% by weight, with 10% being preferred. The second constituent of the mixture, that is, the halogenated nonvolatile organic compound, may vary between 8% by weight and by weight, the preferred percentage being 5%.

To exemplify the concept of this invention, the following examples are given:

Three samples of phospho-sulfurized wool grease, prepared as 50% concentrates in oil according to the general procedure given above, gave on analysis the following percentages of sulfur and phosphorus:

Per Cent S Per Cent P Product A. 7. 98 2. 51 Product 13 6. 70 1.09 Product 0 5.01 1.00

2.5 percent by weight of the 50% concentrate Product A and '7.5% by weight of a chlorinated wax having a chlorine content of 40% were blended in the base oil. The combination gave exceptional results in the SAE test and in the Timken test, and carried the maximum number of weights in the Almen shock test. Data obtained on this blend, and on blends of the two additives employed singly are shown in Table I.

Table I EXTREME PRESSURE LABORATORY TESTS SAE Additive, Per Cent by Weight Test Timken figs in Base 01] 1000 OK Load W h R. P. M. t

2.5% Product A 7.5% Chlorinated Wax 335 15 10% ProductA 100 51 5 10% Chlorinated Wax 282 51 13 None 60 10 l EXAMPLE II Blends of the 50% concentrate Product B and (a) chlorinated wax containing 40% chlorine, (b) chlorinated Ca and C9 aromatic naphtha (mostly methyl and ethyl derivatives of benzene) having a chlorine content of 28.8%, and (c) chlorinated methyl ester of tall oil having a ch1o-" SAE Test Almen Test Additive Per Cent by Tlmkcn Blend wei htm Base Oil {2 OK Load ggf f 2.57 Product B a {7.57; Chlorinated wax.-. 281 68 15 10% Product B b 57hChlorinatcd Naph- 302 a. 10% Product B c 5% Chlorinated Tall Oil 321 1 Not determined.

It will be observed from a comparison of test blends (a) and (d) that substitution of a part of the chlorinated wax in blend ((1) with Product B had little or no effect on the results obtained in the SAE and Almen tests. It is noteworthy, however, that in the type of service exemplified by the Timken test, the performance was measurably improved, and that the combination carried the maximum number of weights in the Ahnen Shock test. Product B was of course only a 50% concentrate, so that these good results were obtained with a smaller total weight of active ingredients. In test blends (b) and (c) the proportion of Product B was increased to 10%, containing 5% of active phospho-sulfurized degras and 5% of the chlorine-containing compound. The high SAE ratings of J02 and 321 should be noted.

EXAMPLE III A lubricant comprising 10% by weight of phospho-sulfurized degras containing 5% sulfur and 1.0% phosphorus, that is, Product C, and 5% by weight of chlorinated wax containing 40% chlorine in the test oil gave the following inspections:

Gravity 23.3 Flash point (F.) 4.45 Vis/ F 1002 Vie/210 F 87.9 Viscosity index 94.6 Sulfur, weight per cent 0.86 Phosphorus, weight per cent 0.11 Chlorine, weight per cent 2.44

When tested in the Copper strip test at 250 F., this material gave a light peacock color, which is a passing grade in the test.

This lubricant performed very satisfactorily in the CRC L19 (high speed) full scale automotive axle test. This is the Army ordnance department specification test No. AXS-1569 designed to simulate high speed'passenger car service. In addition, this composition also gave very satisfactory performance in the CRC L-20 (high torque) full scale axle test designed to simulate low speed, high torque conditions representative of heavy duty truck service which is the ordnance specification test No. AXS-15'70. Moreover, the lubricant performs satisfactorily in the G. M. Chevrolet dynamometer shock test (Federal specification VV-L-761) a test designed to represent extremely severe passenger car service.

Most materials of the prior art give a satisfactory performance in one type of service and poor performance under other types of operating conditions. The composition of this invention, however, is unusual in that it exhibits excellent all-purpose performance, giving satisfactory performance in all three of these types of service.

What is claimed is:

1. A lubricating composition which comprises a major amount of a lubricating oil base stock and a minor amount of a mixture of about 2 /2% to 10% by weight of a 50% oil concentrate of a P285 treated degras analyzing from about 5.01% to 7.98% sulfur and from about 1.0% to 2.51% phosphorus, and about 5% to 7.5% chlorinated wax containing about 40% chlorine.

2. A lubricating composition which comprises 90% of a lubricating oil base stock, 2.5 weight percent of a 50% oil concentrate of a P2S5 treated degras analyzing 7.98% sulfur and 2.51% phosphorus and 7.5 weight percent of a chlorinated wax containing about 40% chlorine.

3. A lubricating composition which comprises 90% of a lubricating oil base stock having blended blended therein 10% of a 50% oil concentrate of P285 treated degras analyzing 5.01% sulfur and 1% phosphorus and 5% of a chlorinated Wax containing about chlorine.

WALTER E. WADDEY. ELMER B. CYPHERS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,383,495 Musselman Aug. 28, 1945 2,468,031 Burk Apr. 26, 1949 2,468,520 Sproule et a1 Apr. 26, 1949

Claims

1. A LUBRICATING COMPOSITION WHICH COMPRISES A MAJOR AMOUNT OF A LUBRICATING OIL BASE STOCK AND A MINOR AMOUNT OF A MIXTURE OF ABOUT 2 1/2% TO 10% BY WEIGHT OF A 50% OIL CONCENTRATE OF A P2S5 TREATED DEGRAS ANALYZING FROM ABOUT 5.01% TO 7.98% SULFUR AND FROM ABOUT 1.0% TO 2.51% PHOSPHOROUS, AND ABOUT 5% TO 7.5% CHLORINATED WAX CONTAINING ABOUT 40% CHLORINE.