US3280028A

US3280028A - Lubricants containing load-carrying additives

Info

Publication number: US3280028A
Application number: US254422A
Authority: US
Inventors: Howard J Matson
Original assignee: Sinclair Research Inc
Current assignee: Sinclair Research Inc
Priority date: 1963-01-28
Filing date: 1963-01-28
Publication date: 1966-10-18
Anticipated expiration: 1983-10-18

Description

United States Patent M 3,280,028 LUBRICANTS CONTAINING LOAD-CARRYING ADDITIVES Howard J. Matson, Harvey, 11]., assignor to Sinclair Research, Inc., Wilmington, Del., a corporation of Delaware No Drawing. Filed Jan. 28, 1963, Ser. No. 254,422 9 Claims. (Cl. 252-46.6)

This invention relates to a method of producing lubricating oils having a markedly increased Timken safe load value.

Among the extreme pressure tests that lubricating oil blends are generally required to meet is the regular Timken break-down test. Many gear oil consumers, for instance, specify a high T imken load, usually a 50-pound minimum safe load. Now, although there are many excellent extreme pressure agents that provide highly satisfactory results with regard to other extreme pressure tests such as the Shell-4 Ball Wear, Falex and SAE tests, it is not uncommon in many cases to find that they fail to meet the Timken safe load specifications.

It has now been found that the Timken safe load value of lubricating oils containing small effective amounts of each of an oil-soluble sulfurized fatty oil and an oilsoluble phosphorus sulfide-hydrocarbon reaction product can be markedly improved by heating the additive combination at a temperature between about 200" and 350 F., preferably about 225 to 275 F. The heating can be of the additive combination per se after which it is incorporated into the lubricating oil base, or it can be of the additive combination in a mineral oil as, for instance, the lubricating oil base, which base may be present in amounts up to those reducing the concentration of the additive combination to that desired in the final lubricating oil composition. It is preferred, however, to heat the additive combination separately, that is, prior to its addition to the lubricating oil base since a more rapid increase in the Timken load value at lower temperatures is found than is obtained from heating a mixture or blend of the additives and base oil and in many instances the preferred procedure results in a higher Timken load value.

The heating step of the present invention is continued for a time suifi-cient to increase the ability of a given amount of the additive to increase the Timken safe load value of the final lubricating oil composition significantly, for example, at least about 15 pounds. The heating periods may vary with the heating temperature selected, a more rapid increase in Timken load value generally being obtained with the higher temperatures, and generally the time will be for at least about 0.5 hour up to 10 hours or more under preferred temperatures. Longer heating times may be necessary when lower temperatures within the prescribed range are employed. When heating an admixture of the additive combination and the base oil, temperatures are selected so that a heating period of not much more than about 2 hours is employed. Heating for longer periods of time is generally uneconomical on a commercial scale. On the other hand, when the additives are heated separately the time period can be longer than about 2 hours, for example, up to 10 hours, preferably about 2 to 5 hours and still stay within economical limits.

The phosphorus sulfide-hydrocarbon materials of the present invention, are the reaction products of a sulfide of phosphorus with a suitable hydrocarbon material of lubricating viscosity such as a material of natural petroleum 3,280,028 Patented Oct. 18, 1966 origin, for example, a heavy hydrocarbon oil of lubricating viscosity having a molecular weight above about 500, i.e. residual lubricating oils, or a synthetic hydrocarbon material such as an olefin or olefin polymer having a molecular weight of from about 400 to 2000 or more. The sulfide of phosphoruswhich may be employed with the hydrocarbon material is preferably phosphorus pentasulfide, P 8 although P 8 P 8 or other phosphorus sulfides or mixtures thereof can be used. Ordinarily, the phosphorus sulfide-hydrocarbon reaction is carried out at a temperature of from about 200 to 500 F., preferably about 400 to 500 F., and in a non-oxidizing atmosphere, such at an atmosphere of nitrogen. The amount of phosphorus sulfide which can be used may range from 1 percent to 50 weight percent and is preferably from about 5 percent to 25 percent of the hydrocarbon material. The final reaction product will usually contain from about 1 to 6% by weight of organically combined phosphor-us.

In a preferred embodiment, a hydrocarbon material such as a mineral oil bright stock or cylinder stock having a viscosity within a range of about to 300 SUS at 210 F. is reacted with 7 to 17 weight percent of phosphorus pentasulfide at a temperature between about 400 to 500 F. for a period of about 10 to 20 hours. By reacting a phosphorus sulfide with a bright stock, for example, the formation of oil-insoluble products which are prosludging in typical lubricating oil blends are greatly reduced as compared to the reaction with a lighter oil, such as a neutral oil, which affords a larger percentage of insoluble reaction products. Ordinarily, if the reaction mixture contains insoluble products these materials can be removed by filtration or centrifugation performed at an elevated temperature, usually about to 280 F. Other suitable hydrocarbon oils which can be reacted with phosphorus sulfide include olefins such as cetene, melene, high molecular weight alkenes obtained by cracking petroleum oil, etc. and olefin polymers such as those obtained from the liquid phase polymerization of butylene and isobutylene in the presence of a Friedel-Crafts type catalyst.

The phosphorus sulfide hydrocarbon reaction product is added to the lubricating base oil in small amounts usually about 0.5 to 5%, preferably about 1 to 3%. The weight ratio of the sulfurized fatty oil component to the phosphorus sulfide hydrocarbon material can range from about 1 to 5: 1, preferably about 2 to 3:1.

The sulfurized fatty oil which forms the second component of the additive combination is a natural or specially prepared ester of unsaturated fatty oils having 12 to 20 carbon atoms in the fatty or acid radicals, sulfurized as with sulfur flowers, for example, at a temperature of about 350 F. for 6 hours to provide about 9 to 14% sulfur in the ultimate product. It is generally added to the lubricating oil in minor amounts, for instance about 2 to 10%, preferably about 3 to 5% by weight.

The lubricating oil base stock used in the present invention is of lubricating viscosity and can be, for instance, a solvent extracted or solvent refined mineral oil obtained in accordance with conventional methods of solvent refining lubricating oils. Generally, lubricating oils have viscosities from about 20 to 250 SUS at 210 F. The base oil is present in major amounts and may be derived from parafiinic, naphthenic, asphaltic or mixed base petroleum crudes and if desired, a blend of solvent-treated 3 Mid-Continent neutrals and Mid-Continent bright stocks may be employed. A particularly suitable base oil used in the preparation of the composition may be described as a lubricating mineral oil fraction having a viscosity index of about 100.

If desired other additives may be included in the lubricating oil composition of the present invention so long as they do not have an unduly adverse elfect upon the increased Timken load value provided by the method of this invention. These additives can be, for example, other extreme pressure agents, pour depressors, corrosion inhibitors, anti-foam agents etc.

The following examples are included to further illustrate the present invention.

Example I To a base oil consisting of 38% of a Mid-Continent lubricating oil having a viscosity of about 46 SUS at 210 F. and 62% of a Mid-Continent lubricating oil having a viscosity of about 150 SUS at 210 F. was added 6.7% of an additive combination, designated A, having the following composition:

Percent Phospho-sulfurized mineral oil bright stock (1.5%

S) 30 Sulfurized sperm oil (11% S) 67.5 Lauric acid 2.2 Trioxane 0.3

and the mixture was blended by heating up to 140 F. with stirring for 20 minutes. Timken safe load tests on the blend ranged from 30 to 40 pounds.

A portion of the blend was then heated at 200 F. for 40 hours and Timken safe load values of the blend at various intervals during the heating were determined. Another portion of the blend was heated with stirring for 1 hour at 250 F. The results of the tests are shown in Table I below:

TABLE I Regular Timken Safe Load, Pounds Time, Hours Blend Blend Blend Heated at Heated at F 1 Blend prepared by heating base oil and additives for minutes at 140 The data show that heating a blend of a lubricating base oil and an additive combination containing a sulfurized sperm oil and phosphosulfurized mineral oil as extreme pressure agents at 200 F. up to 16 hours results, if anything in a decrease in load capacity. After 24 hours, however, a higher Timken load of 50-pounds is obtained, increasing to 65 pounds after 40 hours. The data also show that heating the blend at a higher temperature. i.e. 250 F for only an hour provides a Timken safe load value of 60 pounds. In comparison the essentially unheated blend exhibited a Timken load of to 40.

Example 11 In this example one portion of the additive combination A of Example I was heated at 200 F. for hours and another portion at 250 F. for 16 hours. At periodic intervals during the heatings, samples of the heated additive combination were added to the base oil of Example I in an amount of 6.7% by weight and the Timken safe load value of the resulting blend was determined. The results are shown in Table II below:

TABLE II Regular Timken Safe Load, Pounds Time, Hours Additive Additive Additive Package A Package A Package A Unheated 1 Heated at Heated at 1 Blended with base oil by heating for 20 minutes at 140 F.

The data of Table II demonstrate that heating the sulfurized fatty oil-phosphorus sulfide hydrocarbon combination per se in accordance with the method of the present invention, also provides an increased Timken safe load value when the combination is added to the base oil. The results show further that heating the addit-ive combination itself at 200 F. appears to effect a more rapid increase in Timken load value than obtained when the oil blend is heated at the same temperature and that an ultimately higher load value is obtained. Best results, are obtained when the additive combination itself is heated at a temperature of about 250 F. In this treatment a Timken safe load of pounds was obtained after only one hour, increasing to 70 pounds after two hours, and to more than 80 pounds, with no failure, after eight hours.

It is claimed:

1. An additive combination which consists essentially of an oil-soluble sulfurized unsaturated ester of a fatty acid having 12 to 20 carbon atoms in the fatty acid radical and an oil-soluble phosphorus sulfide-hydrocarbon oil reaction product, heated at a temperature of about 200 to 350 F. and for a time sufiicient to increase its Timken load value increasing characteristics, the weight ratio of said sulfurized unsaturated ester to said phosphorus sulfide-hydrocarbon oil reaction product being about 1 to 5:1.

2. The additive combination of claim 1 wherein the sulfurized ester is sulfurized sperm oil.

3. The additive combination of claim 2 wherein the phosphorus sulfide hydrocarbon reaction product is prepared by reacting about 7 to 17 weight percent of phosphorus pentasulfide with a mineral oil bright stock at a temperature between about 400 to 500 F. for about 10 to 20 hours.

4. A lubricating oil composition having an improved Timken breakdown load value consisting essentially of a mineral lubricating oil and small amount sufiicient to increase the Timken breakdown load value of said oil of the heated additive combination of claim 1.

5. The composition of claim 4 wherein the phosphorus sulfide-hydrocarbon oil reaction product is prepared by reacting about 7 to 17 weight percent of phosphorus pentasulfide with a mineral oil bright stock at a temperature between about 400 to 500 F. for about 10 to 20 hours.

6. A lubricating oil composition having an improved Timken breakdown load value consisting essentially of a mineral lubricating oil and a small amount sufiicient to increase the Timken breakdown load value of said oil of an additive combination which consists essentially of oil-soluble, sulfurized sperm oil and an oil-soluble phosphorus sulfide-hydrocarbon oil reaction product, said combination having been heated at a temperature of about 200 to 350 F. and for a time sufficient to improve its Timken load value increasing characteristics, the weight ratio of said sulfurized sperm oil to said phosphorus sulfide-hydrocarbon oil reaction product being about 1 to 5:1.

7. A process for producing a lubricating oil composition having an improved Timken breakdown load value which comprises heating at a temperature of about 200 to 350 F., a mineral base oil of lubricating viscosity having added thereto a small effective amount of each of an oilsoluble sulfurized unsaturated ester of a fatty acid having 12 to 20 carbon atoms in the fatty radical and an oilsoluble phosphorus sulfide-hydrocarbon oil reaction product, the weight ratio of said sulfurized ester to said sulfide-hydrocarbon oil reaction product being about 1 to 5:1, and the heating being conducted for a time sufficient to increase the T imken breakdown load value of the lubricant by at least 15 pounds.

8. The process of claim 7 wherein the sulfurized ester is sulfurized sperm oil.

9. The process of claim 7 wherein the phosphorus sulfide-hydrocarbon reaction product is prepared by reacting about 7 to 17 weight percent of phosphorus pentasulfide with a mineral oil bright stock at a temperature of about 400 to 500 F. for a period of about 10 to 20 hours.

References Cited by the Examiner UNITED STATES PATENTS 2,640,030 5/1953 Fischl et a1. 252-46.6

4/1943 K6180 et al. 25246.6

Claims

1. AN ADDITIVE COMBINATION WHICH CONSISTS ESSENTIALLY OF AN OIL-SOLUBLE SULFURIZED UNSATURATED ESTER OF A FATTY ACID HAVING 12 TO 20 CARBON ATOMS IN THE FATTY ACID RADICAL AND AN OIL-SOLUBLE PHOSPHORUS SULFIDE-HYDROCARBON OIL REACTION PRODUCT, HEATED AT A TEMPERATURE OF ABOUT 200 TO 350*F. AND FOR A TIME SUFFICIENT TO INCREASE ITS TIMKEN LOAD VALUE INCREASING CHARACTERISTICS, THE WEIGHT RATIO OF SAID SULFURIZED UNSATURATED ESTER TO SAID PHOSPHORUS SULFIDE-HYDROCARBON OIL REACTION PRODUCT BEING ABOUT 1 TO 5:1.

4. A LUBRICATING OIL COMPOSITION HAVING AN IMPROVED TIMKEN BREAKDOWN LOAD VALUE CONSISTING ESSENTIALLY OF A MINERAL LUBRICATING OIL AND SMALL AMOUNT SUFFICIENT TO INCREASE THE TIMKEN BREAKDOWN LOAD VALUE OF SAID OIL OF THE HEATED ADDITIVE COMBINATION OF CLAIM 1.