US2726209A

US2726209A - Extreme pressure lubricant

Info

Publication number: US2726209A
Application number: US453435A
Authority: US
Inventors: Fainman Morton
Original assignee: Standard Oil Co
Current assignee: Standard Oil Co
Priority date: 1954-08-31
Filing date: 1954-08-31
Publication date: 1955-12-06
Anticipated expiration: 1972-12-06

Description

United States Patent v 7 2,726,209 EXTREME PRESSURE LUBRICANT Morton Fainman, Chicago, Ill., assignor to Standard Oil Company, Chicago, 111., a corporation of Indiana.

' N0 Drawing. Application August 31, 1954, Serial No. 453,435

7 Claims. (Cl. 25233.6)

This invention relates to improvements in lubricants and, in particular, to improvements in extreme pressure lubricants adapted for use onbearing surfaces which are subjected to high pressures and high rubbing velocities during use. In a more particular sense, the invention relates to the method of preparing such lubricants.

High unit pressures which are encountered frequently in devices employed for transmission of power, such as hypoid gears, worm gears, heavy duty bearings, planetary automatic shifts, and the like, necessitate the use of lubricants having superior load carrying properties. Lubricants possessing superior load carrying properties which make them specially adapted for use under conditions of high pressure where the pressures encountered are of such magnitude that the separation of gear teeth or bearing surfaces by an ordinary oil filament is not possible, are well-known in the art as extreme pressure lubricants.

Extreme pressure lubricants are likewise important in cutting and drawing operations where the oil must withstand the high pressures encountered under those conditions of use. I

It is an object of this invention to provide an improved extreme pressure lubricant which will give superior lubri cation to bearing surfaces which are subjected to high pressures and/ or high rubbing velocities. Another object of the invention is to provide a lubricant which will prevent gear teeth or bearing failure from scoring or galling caused by welding of small areas of the mating surface due to high pressure and high temperature.

I have found that the foregoing objects can be attained if there is present in the lubricating oil the reaction product obtained by heating a mixture of sulfur-containing lead tallate, a chlorinated mixture of hydrocarbons such as chlorinated paraflin Wax of high chlorine content, i. e., a chlorinated hydrocarbon oil or chlorinated paratfin wax of about 40% to 70% by weight of chlorine, oleic acid and said lubricating oil at a temperature within the range of from about 225 F. to about 275 F. for a period of at least hours and not more than about 120 hours, for example, about 20 hours. This heating or aging step of the process may be carried out in the presence of a small amount of water and preferably in the presence of a small amount of water and a catalytic amount of a finely divided metal, selected from the class consisting of finely divided iron and finely divided copper. I prefer iron or copper of particle size which passes through a #100 U. 8. standard screen.

I have been unable to determine the exact composition of the product obtained as a result of heating the above mixture of components. However, I believe that the ex cellent extreme pressure properties imparted to my novel composition are due to some component of the natural tall oil which acts as a chlorine acceptor whereby a chlorinated component of the tall oil is formed, thereby pro viding a component to the mixture which contains chlo- ICC line, received in the heating step from the chlorinated wax component. This formation in situ of the active component is brought about by the final heating step as indicated hereinbelow. r a

More specifically, the process of preparing the lubricant involves the steps of sulfurizing tall oil at a tempera ture of from about 300 F. to about 350 F. with free sulfur to provide a sulfurized product containing from about 5% to 15% sulfur. This sulfurizing step is usually complete in a'period of from 10m 15 hours. The reaction is completed to form a sulfur-containing tall oil product which is non-corrosive to copper when placed in contact with copper at 250 F. for a period of 10 minutes. The sulfur-containing tall oil products should contain about 5% to about 15%, preferably about 8% to about 10% of sulfur. The sulfur-containing tall oil is then diluted with a lubricating oil, preferably of relatively high aromatic hydrocarbon content, of SAE grade #10, #20, #30, #40, #50, or #60, or blends of these, the

amount of diluent oil being equal by weight to the Weight of sulfurized tall oil. The viscosities of lubricating oils of these grades fall within the range of from about 40 seconds to 200 seconds at 210 F. (SSU); .If desired,

' prior to adding the lubricating oil diluent to the sulfurized tall oil, an amount of an oxide of lead such as litharge equal to about 20% by weight of the sulfurized tall oil to be reacted in forming the sulfur containing lead tallate, may be slurried in the diluent oil or the lead oxide 7 may be added to the mixture after the diluent is added to the sulfurized tall oil. The diluted sulfurized tall oil containing lead oxide is then heated at a temperature within the range of about 220 F. to about 230 F. to produce the sulfur-containing lead tallate component. To this diluted, heated mixture is then added a mixture of chlorinated paraffin wax and oleic acid. If desired, this addition may be made simultaneously with another portion of lubricating oil diluent. The mixture is stirred and held at a temperature within the range of F. to F. for a period of time sufiicient to provide a homogeneous mixture of the sulfur-containing lead tallate, oleic acid, chlorinated paraffin wax, and lubricating oil components. This homogeneous mixture is then heated at a temperature within the range of 225 F. to about 275 F. for a period of at least 10 hours and not more than about '120 hours, preferably in the presence of a small amount of water, i. e., from about 0.1% to about 1.0% of water based on the weight of the mixture, and in the presence of from about 0.05% to about 0.5% by weight, based on the weight of the mixture, of a finely divided metal such as finely divided iron or finely divided copper. The product obtained according to this procedure may be diluted further with the lubricating oil following the heating, i. e., aging, step of the process to provide a finished lubricating oil having the following approximate weight percent composition:

Lubricating oil (1060 SAE grade) 74-92 Sulfur-containing lead tallate 5-10 Chlorinated paraffin wax (4070% C12) 1-'-10 Oleic acid 2-6 To this composition may be added about two parts per million of a silicone antifoaming agent.

The load-carrying capacity of extreme pressure lubricants may be determined by extreme pressure testing machines, such as the Timken testing machine, described in the Journal of the Institute of Petroleum 32, pp. 209-210 and 220-222 (1946). The mechanism and method of 1 use of the machine is well-known by those skilled in the Patented Dec. 6, 19 55 art of testing petroleum products. In testing to determine the load a lubricant will carry, a test is made using a load the oil will carry readily and then successive tests are made using slightly increased loads until failure occurs. The results of tests obtained in testing formulations illustrating my invention, formulations which contain sulfur-containing lead soaps other'than sulfur-containing lead tallate and formulations containing the sulfurized lead tallate with chlorinated paraffin wax component, with and without the presence of water and iron or copper catalyst are discussed hereinbelow and are shown in Tables I and II below.

Example 1' One thousand grams of tall oil 1 were heated at a temperature of 300 F. to 320 F. over a period of hours, during which period 100 grams of flowers of sulfur were added in small increments. The sulfurized oil was noncorrosive to copper and contained 9.14% sulfur. This product was then diluted with an equal weight of a Mid- Continent base (acid-treated) SAE #10 grade oil and heated to a temperature of 220 F. to 230 F. over a period of two hours, during which period 200 grams of litharge were added to the stirred mixture. The oil-diluted sulfur'containing lead tallate product, which was homogeneous, contained 9.7% lead and 4.15% sulfur. To 450 grams of this product was then added 120 grams of oleic acid and 180 grams of Chlorafin-42 and 2250 grams of base oil (acid treated SAE #50 grade) was added to give a lubricant having the following composition:

Percent Sulfur-containing lead tallate 7.5 Chlorafin-42 -c 6.0 Oleic acid 4.0 SAE #10 oil diluent 7.5 Base oil (SAE 50 grade) 75.0

The composition was stirred and held at a temperature of 140 F. to 160 F. for a period of one hour to facilitate the production of a homogeneous lubricant product. A silicone antifoam agent was added to the extent of 2 parts by weight per million. The finished extreme pressure lubricant contained 1.01% sulfur, 2.62% chlorine and 0.96% lead. It had a viscosity of 1293 seconds at 100 F. and 94.4 seconds (SSU) at 210 F.

The above product was tested for extreme pressure properties after modification in a series of heating experiments. The following samples were tested. Results are shown in Table I.

a. Base oil containing no extreme pressure agent.

b. Above non-heated formulation (of Example 1).

c. Formulation of b, mixed with 0.1% finely divided iron and 0.5% water at room temperature.

11. Formula of b, mixed with water and finely divided iron as per c, and heated to 250 F. for less than /2 hour.

e. Formula of b, blown with air for 53 hours at 250 F.

1. Formula of b, heated at 250 F. for a period of 100 hours.

g. Formula of b, heated and stirred in presence of 0.5% water for period of 100 hours.

- 11. Formula of b, stirred with iron and water and heated for period of 100 hours.

i. Formula of b, stirred with 0.1% finely divided copper and 0.5% water for period of 100 hours.

i. Formula of b, stirred with 0.06% iron (as iron naphthenate) at room temperature for 100 hours.

k. Formula of j, stirred and heated for 100 hours at 250 F.

In addition to the above test samples results for which are shown in Table I, a formulation containing lead naph- A commercial grade of tall oil, Indusoil (double distilled) marketed by Industrial Chemical Sales Division, West Virginia Pulp and Paper Co.

11 Commercial chlorinated parafiin wax containing 40-42% chlorine (Chlorafin-42, product of Hercules Powder Com- P y thenate, sulfurized sperm oil, Chlorafin and oleic acid corresponding to the following composition:

Lead naphthenate Percent by weight 5 Sulfurized sperm oil do 5 Chlorafin-42 do 6 Oleic acid do 4 Base oil (SAE grade) do 80 Antifoam agent p. p. m 2

was heated and stirred at 250 F. for a period of 100 hours in the presence of 0.1% finely divided iron and 0.5% water. The non-heated formulation passed" in the Timken test at 50 lbs. and failed at lbs. The heated sample passed at 45 lbs. but failed at 50 lbs. Likewise, a formulation corresponding to the following composition:

Percent Sulfurized lead oleate 7.5 SAE #10 oil diluent 7.5 Chlorafin 6.0 Oleic acid 4.0 Base oil (SAE 50 grade) 75.0

passed at 55 lbs. and failed at lbs. After aging in the presence of 0.1% finely divided iron and 0.5% water for 100 hours at 250 F. passed at 45 lbs. and failed at 50 lbs.

TABLE I 'Ilmken Load Sample lbs. pass lbs. fail A series of heat treatments of the formulation contain ing the sulfurized lead tallate, Chlorafin and oleic acid prepared in Example 1 was made wherein the formulation was stirred and heated for different periods of time in the presence of 0.1% by weight of finely divided iron and 0.5% by weight of water, in the absence of iron catalyst, and in the absence of water. The results of Timken tests of these samples are shown in Table II.

TABLE Il Aging study of sulfur-containing lead tallare formulation Referring to Tables I and II it can be seen that heating the formulation made up of the sulfur-containing lead tallate, chlorinated wax, i. e., Chlorafin, oleic acid, and lubricating oil at a temperature of 250 F. for a period of 24 to 96 hours raises the Timken value markedly. If this heating operation is carried out in the presence of finely divided iron or copper as catalyst and in the presence of water, the improvement in Timken values is still greater.

Chlorinated compounds of various types are employed in extreme pressure lubricants. For example, products obtained by chlorinating parafiin wax are particularly adaptable in the present improved formulation and method of preparing the finished heated composition. These chlorinated wax compositions are described in Encyclopedia of Chemical Technology, vol. 3, page 782, 1949 (The Interscience Encyclopedia, Inc., New- York 3, N. Y.). While I prefer those chlorinated hydrocarbons containing from about 40% to 55% chlorine (by weight), which are usually liquid at ambient temperatures, higher chlorine content chlorinated hydrocarbons containing up to about 70% chlorine may be used. Chlorine-containing components are employed in accordance with my invention in sufficient amount to afford a total chlorine content in the lubricant of from about 0.3% to about 8% and preferably from about 1% to about 3% by weight.

The tall oil used in the above example was, as indicated above, a sample of Indusoil double-distilled tall oil of relatively high purity. Typical range of analyses of this grade is as follows:

While I prefer to use tall oil of grade equal to the above, I do not wish to be limited to the use of a highly purified grade of tall oil since crude tall oil may be used in my formulation of improved lubricant. However, the whole natural tall oil product must be used. Thus, I have prepared a synthetic tall oil containing 50% rosin acids, 25% oleic acid, and 25% linoleic acid. The mixture sulfurized readily and the lead soap was soluble in oil. When this sulfur-containing lead soap was substituted for the sulfur-containing lead tallate in the above formulation of Example 1, the lubricant passes the Timken test at 60 lbs. and failed at 65 lbs. However, aging the lubricant by heating at 250 F. in the presence of finely divided iron and water failed to improve the lubricant.

Having thus described my invention, I claim:

1. A composition suitable for use as a lubricating oil for the lubrication of metal to metal contact surfaces under conditions of extreme pressure between said contact surfaces, which composition is obtained by heating at a temperature of 225 F. to 275 F. for at least 10 hours and not more than 120 hours, a mixture consisting essentially of 5 to parts by weight of sulfur-containing lead tallate slurried in 5 to 10 parts by weight of a lubricating oil diluent having a viscosity within the range of about 40 to about 200 at 210 F. (SSU), 1 to 10 parts by Weight of a chlorinated parafiin wax of chlorine content Within the range of about 40 to about 70% by weight of chlorine and from about 2 to about 6 parts by weight of oleic acid and adding suflicient lubricating oil having a viscosity of about 40 to about 200 seconds at 210 F. (SSU) to provide a total of 100 parts by weight of said lubricating oil composition which sulfur-containing lead tallate is produced by sulfurizing tall oil with free sulfur to obtain a sulfur-containing tall oil product containing 5 to by Weight of sulfur and non-corrosive to copper and heating at a temperature of about 220 F. to about 230 F., a slurry of said sulfur-containing tall oil in said lubricating oil diluent in the presence of about by weight, based on the weight of said sulfur-containing tall oil, of an oxide of lead suspended in said lubricating oil acid is carried out in the presence of from about 0.05 to a 0.2 part by weight, based on the weight of said mixture, of finely divided metal selected from the class consisting of iron and copper.

3. A lubricating oil composition as described in claim 2, the total lubricating oil content of which is within the range of from about 74% to 92% by weight of'said lubricating oil composition.

4. The process for preparing a lubricant suitable for use in the lubrication of metal to metal contact surfaces under conditions of extreme pressures between said contact surfaces, which process comprises the steps of (1) sulfurizing tall oil at a temperature of about 300 F. to 350 F. with free sulfur to contain from about 5% to about 15% of sulfur, said sulfurized tall oil being noncorrosive to copper, (2) contacting at about 220 F. to 230 F. the product of step 1 with litharge to produce a sulfur-containing lead tallate product, (3) commingling a mixture of a chlorinated paraflin wax containing about 40% to about by weight chlorine, oleic acid, and a hydrocarbon oil diluent of lubricating oil viscosity range of from about 40 seconds to 200 seconds at 210 F. (SSU) with the product of step 2 at a temperature within the range of about F. to F. for a period of time suflicient to provide a homogeneous mixture of sulfur-containing lead tallate, oleic acid, chlorinated paraflin wax, and lubricating oil diluent components and (4) heating the homogeneous mixture of step 3 at a temperature of about 225 F. to about 275 F. for a period of at least 10 hours and not more than about 120 hours.

5. The process as described in claim 4, wherein the heating operation of step 4 is carried out in the presence of Water added to the homogeneous mixture in an amount within the range of about 0.1% to 1.0% by weight of said mixture.

6. The process as described in claim 5 wherein the heating operation of step 4 is carried out in the presence of from about 0.05% to about 0.5% by weight, based on the weight of said mixture, of a finely divided metal selected from the class-consisting of iron and copper.

7. An extreme pressure lubricant consisting essentially References Cited in the file of this patent UNITED STATES PATENTS 2,175,491 Stresen-Reuter Oct. 10, 1939 2,202,394 Morway May 28, 1940 2,472,503 Minne June 7, 1949 OTHER REFERENCES Ind. Eng. Chem. 42, No. 9 (1837-1841), 1950.

Claims

1. A COMPOSITION SUITABLE FOR USE AS A LUBRICATING OIL FOR THE LUBRICATION OF METAL TO METAL CONTACT SURFACES UNDER CONDITIONS OF EXTREME PRESSURE BETWEEN SAID CONTACT SURFACES, WHICH COMPOSITION IS OBTAINED BY HEATING AT AT TEMPERATURE OF 225* F. TO 275* F. FOR AT LEAST 10 HOURS AND NOT MORE THAN 120 HOURS, A MIXTURE CONSISTING ESSENTIALLY OF 5 TO 10 PARTS BY WEIGHT OF SULFUR-CONSISTING LEAD TALLATE SLURRIED IN 5 TO 10 PARTS BY WEIGHT OF A LUBRICATING OIL DILUENT HAVING A VISCOSITY WITHIN THE RANGE OF ABOUT 40 TO ABOUT 200 AT 210* F. (SSU), 1 TO 10 PARTS BY WEIGHT OF A CHLORINATED PARAFFIN WAX OF CHLORINE CONTENT WITHIN THE RANGE OF ABOUT 40 TO ABOUT 70% BY WEIGHT OF CHLORINE AND FROM ABOUT 2 TO ABOUT 6 PARTS BY WEIGHT OF OLEIC ACID AND ADDING SUFFICIENT LUBRICATING OIL HAVING A VISCOSITY OF ABOUT 40 TO ABOUT 200 SECONDS AT 210*F. (SSU) TO PROVIDE A TOTAL OF 100 PARTS BY WEIGHT OF SAID LUBRICATING OIL COMPOSITION WHICH SULFUR-CONTAINING LEAD TALLATE IS PRODUCED BY SULFURIZING TALL OIL WITH FREE SULFUR TO OBTAIN A SULFUR-CONTAINING TALL OIL PRODUCT CONTAINING 5 TO 15% BY WEIGHT OF SULFUR AND NON-CORROSIVE TO COPPER AND HEATING AT A TEMPERATURE OF ABOUT 220* F. TO ABOUT 230* F., A SLURRY OF SAID SULFUR-CONTAINING TALL OIL IN SAID LUBRICATING OIL DILUENT IN THE PRESENCE OF ABOUT 20% BY WEITHT, BASED ON THE WEIGHT OF SAID SULFUR-CONTAINING TALL OIL, OF AN OXIDE OF LEAD SUSPENDED IN SAID LUBRICATING OIL DILUENT.