US2491649A - Lubricant composition - Google Patents

Description

Patented Dec. 20, 1949 LUBRICANT COMPOSITION Gordon W. Duncan, Westfleld, and John C. Zimmer, Union, N. J., Issignors to Standard Oil Development Company, a corporation of Delaware No Drawing. Application February 9, 1946, Serial No. 646,706

14 Claims.

The present invention relates to the field of mineral oil lubricants generally, and more particularly to improved additives to be used in compounding engine oils, extreme pressure lubricants and cuttings oils.

Experience has shown that mineral lubricating oils, when used to lubricate modern internal combustion engines decompose, producing products which accumulate in various parts of the engine, such as on the rings and in the ring grooves in the form of a lacquer and/or carbonaceous deposits, which is probably responsible for ring sticking, causing loss of power and other indications of poor performance. The addition of certain types of metal derivatives of organic compounds is known to improve the properties of these oils, such as their oiliness characteristics and their detergent action in engines, particularly manifest in the maintenance of a clean engine condition during operation. Calcium and other polyvalent metal salts of petroleum or synthetic sulfonic acids are known to have oil detergent properties, but their use is limited due to their corrosive action on certain types of bearings. Mineral lubricating oils and emulslflable oils are also used quite extensively for lubricating and cooling metal cutting tools. In metal cutting, the pressures which are developed between the cutting tool and the work and between the cutting tool and the metal chips exceed the film strength of mineral lubricating oil, and it has therefore been found necessary to incorporate in the mineral oil an agent having loadbearing characteristics commonly designated as an extreme pressure additive.

The principal object of the present invention is the provision of novel load-bearing compounds useful as extreme pressure additives in the compounding of cutting oils, emulsiilable oils, and E. P. lubricants. Another object is the conversion of polyvalent metal sulfonates of engine oil detergent characteristics into a non-corrosive form. These and other objects will be apparent to those skilled in the art upon reading the following description.

It has now been found that the metal salts of oil-soluble sulfonic acids generally. and particularly the metal salts of the preferentially oilsoluble petroleum oil sulfonic acids, may be given load-bearing characteristics and improved as engine oil detergents by reacting them with metal poiysulildes. Particularly suitable sulfonate salts useful as starting materials for the purposes of the present invention are those of the alkali and alkaline earth metals, e. g. sodium, potassium,

2 calcium, magnesium, strontium and barium. However, other polyvalent metal sulionates may be used, such as those of aluminum, iron, zinc, lead, cadmium, cobalt, nickel, etc. These sulionate salts are available in the form of concentrates in oil containing from about to about of these particular sulionate salts in oil. According to the present invention the metal sulfonate concentrate is reacted with a metal polysulfide to produce sulfonate salt compounds having excellent load-bearing properties, as well as improved engine bearing corrosion resistance. The reaction of the sulfonate with the polysulfide is carried out according to the procedure and under the conditions described in copending application Serial No. 564,546, filed November 21, 1944, now Patent No. 2,467,176. Broadly, the method followed in carrying out the reaction is to mix the sulionate concentrate with a poly- 20 sulfide in aqueous solution in the ratio, on a molal basis, of at least 1 mol of sulionate salt per mol of metal polysulfide. The mixture is then heated to 250-325" F., preferably 300-310 E, to drive oil the water and react the polysulilde with the sulfonate salt after which the reaction product is filtered, if necessary, and cooled. In some cases it is desirable to include an alkaline reacting material to give an alkaline product. As an example, 0.1 mol of calcium hydroxide may be included when treating calcium sulfonate with calcium polysulfide, or the reaction product may be reacted with calcium hydroxide. The type of metal polysulfide used in the reaction will depend to some extent upon the use to which the final product is intended. If an E. P. additive and oil detergent is desired, it is preferred to use an alkaline earth metal polysulfide such as calcium, magnesium, strontium, or barium polysuliide, whereas if the product is to be used in an emulsifiable cutting oil composition, an alkali metal polysulfide, such as sodium or potassium polysulfide, is reacted with the sulfonate salt concentrate.

It is believed that the polyvalent metal polysulfides when reacted with oil-soluble suli'onates give oil-soluble complex polyvalent metal sulionates of the Werner type. For the production of a cutting oil, the oil-soluble concentrate of polyvalent metal suli'onate complex is blended with a suitable lubricating oil base to yield a compounded oil containing 1 to 10% of the complex, e. g. when using a 30% concentrate, 3.3% of this material blended in the oil will furnish an oil containing 1% of the effective addition agents and 33% will yield a blend containing 10% of I. P. additives. Soluble oils are blended so as to contain from 2.0 to 20% of sulfonate polysulfide reaction products. As engine oil detergents the additives are blended with lubricating oil base stocks in concentrations between 0.02 and 5.0% and preferably from 0.1 to 2.5%. The exact amount oi addition agent, within the limits prescribed, in each instance will depend upon the nature of the lubricating oil base stock, the general operating conditions and the result desired.

Having described the invention in its general aspects, the following examples will serve to illustrate specific applications thereoi.

trample 1 200 grams oi a solid 30% concentrate oi preferably oil-soluble normal calcium sulionate in oil, containing 1.25% calcium, 2.85% sulfur and 4.30% ash, was mixed with 10 grams of an aqueous solution of calcium polysulfide containing 0.82% calcium and 24.44% suliur (an amount equivalent to 5% calcium polysuliide by weight of the calcium sulionate in the original concentrate). After agitating to secure an intimate mixture, the temperature was raised to 800" F. to drive of! the water. A clear, fluid, odorless product containing 1.51% calcium, 2.93% sulfur and 4.89% ash was obtained. 5% blends oi this product and oi the original untreated concentrate were made up in an extracted naphthenic lubricating oil and then tested for bearing corrosion life as follows: 500 cc. of the blend was placed in a glass oxidation tube (13" long and 2%" in diameter) fed at the bottom with a quarter inch bore air inlet tube perforated to facilitate air dis tribution. The oxidation tube was then immersed in a heated bath so that the oil temperature was maintained at 325 F. during the test. Two quarter sections oi automotive bearings of copperlead alloy of known weight having a total area oi 25 sq. cm. were attached to opposite sides oi a stainless steel rod which was then immersed in the oil and rotated at 600 R. P. 191., thus providing sumcient agitation of the sample during the test. Air was then blown through the oil at the rate or 2 cubic feet per hour for 4 hours. The hearings were then cleaned by washirm with naphtha, dried and weighed and the loss in weight noted; The bearings were then repolished (to increase the severity of the test) reweighed and placed in the oil for another 4 hour period. The test in each case was continued in 4-hour periods until the accumulated loss in weight the bearings exceeded 100 mg. The 5% blend of the original calcium sulionate concentrate caused a bearing weight loss of 96 mg. after 4 hours and 285 mg. after 8 hours. The 5% blend of the reaction product caused no weight loss after 4 hours nor aiters hours and only 31 mg. at 12 hours and 200 mg. after 16 hours.

Example 2 4 Emmplc 3 As a further example oi our invention, an emulsifiable oil of superior load-carrying ability can be prepared employing as the chief emulsifying agent a concentrate of preierably oil-solluble sodium sulfonate which has been reacted with sodium polysulilde. Such a concentrate was prepared as follows:

grams of a 50% oil solution of sodium sulfonate was emulsified with 35 grams of an aqueous solution of sodium polysulfide (1.9% preterably oil-soluble sodium, 6.5% sulfur) and heated to above 250 F. The resultant product was clear, odorless, and quite fluid.

Although the preferably oil-soluble metal sulfonates have been used to illustrate the principles 0! the present invention, metal phenates, phenol sulfides, metal derivatives of phenol sulfides and thiophosphates and their metal salts may also be greatly improved in their bearing corrosion char- :cteristics by reacting them with metal polysuldes.

When the additives of the present invention are employed in crankcase lubricants their action may sometimes be enhanced by using them in conjunction with other additives such as metal soaps, metal phenates, metal alcoholates, metal phenol sulfides, organo substituted acids of phosphorus and metal salts of the same, metal xanthates, other sulfur or phosphorus compounds, nitrogen compounds, pour point depressors, V. I. improvers, oiliness agents and the like. Thus, the additives of the present invention may be used with one or more of the following representative materials:

Barium tert. octyl phenol sulfide Tin salt of wax alkylated phenol sulfide Calcium cetyl phenate Zinc isopropyl xanthate Alumium napthenate Barium di tert, amyl phenol sulfide Zinc tert. octyl phenol sulfide thiophosphate Magnesium lauryl sallcylate Calcium phenyl stearate Zinc di-isopropyl sallcylate Stearyl alcohol Tert. amyl phenol sulfide 2,6-dl tert. butyl-4-methyl phenol Polymerized lauryl methacrylate Sulfur-iced sperm oil Phenyl alpha naphthylamine Dibenzyl disulflde In addition to their use in crankcase oils, extreme pressure lubricants and cutting oils, it is contemplated to employ the additives of the present invention in engine flushing oils, industrial oils, rust preventive compositions and greases.

What is claimed is:

1. A composition of matter consisting essentially of a major amount of a mineral lubricating oil and 0.02 to 10% by weight based on the total composition of the reaction product of at least one molecular proportion of a metal salt of preferentially oil-soluble petroleum oil sulfonlc acid with one molar proportion of a metal polysulilde selected from the alkali and alkaline earth metal polysulfldes, said reaction product being prepared by mixing together a concentrate in mineral oil of said first named metal compound and an aqueous solution of said polysulilde and heating the mixture to a temperature ranging between 250' and 325 F. to complete said reaction and drive oil water.

2. A composition of matter consisting essentially or a major amount of a mineral lubricating oil and 0.02 to by weight based on the total composition of at least one molecular proportion of a polyvalent metal of a preferentially oil-soluble petroleum oil sulionic acid with one molecular proportion of a metal polysulflde selected from the alkali and alkaline earth metal polysulfldes, said reaction product being prepared by mixing together a concentrate in mineral oil of said first named metal compound and an aqueous solution of said polysulfide and heating the mixture to a temperature ranging between 250 and 325 F. to complete said reaction and drive oil water.

3. A composition of matter consisting essentially of a major amount of a mineral lubricating oil and 0.02 to 10% by weight based on the total composition of the reaction product of at least one molecular proportion of preferably oil-soluble calcium sulionate with one molecular proportion of a metal polysulfide selected from the alkali and alkaline earth metal poiysulfldes, said reaction product being prepared by mixing together a concentrate in mineral oil of said first named metal compound and an aqueous solution of said polysulfldc and heating the mixture to a temperature ranging between 250 and 325 F. to complete said reaction and drive off water.

4. A composition of matter consisting essentially of a major amount of a mineral lubricating oil and 0.02 to 10% by weight based on the total composition of the reaction product of at least one molecular proportion of the metal salt of a preferentially oil-soluble petroleum oil sulionic acid with one molecular proportion of an alkaline earth metal polysulfide said reaction product being produced by mixing together a concentrate in mineral oil of said sulfonate and an aqueous solution of said polysulfide and heating the mixture to a temperature ranging between 250 and 325 F. to complete said reaction and drive oil water.

5. A composition of matter consisting essentially of a major amount of a mineral lubricating oil and 0.02 to 10% by weight based on the total composition of the reaction product of at least one molecular proportion of a metal salt of preferentially oil-soluble petroleum oil sulionic acid with one molecular proportion of calcium polysulflde said reaction product being produced by mixing together a concentrate in mineral oil of said sulfonate and an aqueous solution of said polysuiflde and heating the mixture to a temperature ranging between 250 and 325 F. to complete .said reaction and drive oil water.

6. A composition of matter consisting essentially of a major amount of a mineral lubricating oil and 0.02 to 10% by weight based on the total composition of the reaction product of at least one molecular proportion of calcium sulionate and preferentially oil-soluble calcium polysulflde said reaction product being produced by mixing together a concentrate in mineral oil of said sullonate and an aqueous solution of said polysulflde and heating the mixture to a temperature ranging between 250 and 325 F. to complete said reaction and drive on water.

7. A cutting oil composition consisting essentially of a mineral lubricating oil and 140% of the reaction product of at least one molecular proportion of a polyvaient metal salt of a preferentially oil-soluble petroleum oil sulionic acid with one molecular proportion of an alkaline earth metal poiysulflde said reaction product being produced by mixing together a concentrate solution of said polysulflde and heating the mixture to a temperature ranging between 250 and 325 F. to complete said reaction and drive off water.

8. A cutting oil composition consisting essentially of a mineral lubricating oil and l-10% oi the reaction product of at least one molecular proportion of preferentially oil-soluble calcium sulfonate with one molecular proportion of a calcium polysulfide said reaction product being produced by mixing together a concentrate in mineral oil of said sulfonate and an aqueous solution of said polysultlde and heating the mixture to a temperature ranging between 250 and 325 F. to complete said reaction and drive oil water.

9. A cutting oil composition consisting essentially of a mineral lubricating oil and 3.5% of the reaction product of at least one molecular proportion of preferentially oil-soluble calcium sulionate with one molecular proportion of calcium polysulfide, said reaction product being produced by mixing together a concentrate in mineral oil of said sulionate and an aqueous solution of said polysulflde and heating the mixture to a temperature ranging between 250 and 325 F. to complete said reaction and drive oil water.

10. An emulsifiable oil-concentrate consisting essentially of a major proportion of a mineral lubricating oil and 1 to 10% by weight based on the total composition of the reaction product oi at least one molecular proportion of sodium sulfonate with one molecular proportion of preferentially oil-soluble sodium polysulfide, said reaction product being produced by mixing together a concentrate in mineral oil of said sulfonate and an aqueous solution of said polysulflde and heating the mixture to a temperature ranging between 250 and 325 F. to complete said reaction and drive off water.

11. As a composition of matter the reaction product of at least one molecular proportion of a preferentially oil-soluble metal salt of a petroleum sulfonic acid with one molecular proportion of a metal polysulfide selected from the alkali and alkaline earth metal polysulfides, said reaction product being prepared by mixing together a concentrate in minei'ai oil of said first named metal compound and an aqueous solution of said polysulfide and heating the mixture to a tempera ture ranging between 250 and 325 F. to complete said reaction and drive off water.

12. As a composition of matter the reaction product of at least one molecular proportion of a preferentially oil-soluble polyvalent metal petroleum sulfonate with one molecular proportion of a metal polysulflde selected from the alkali and alkaline earth metal polysulfldes, said reaction product being prepared by mixing together a concentrate in mineral oil of said first named metal compound and an aqueous solution of said polysulflde and heating the mixture to a temperature ranging between 250 and 325 F. to complete said reaction and drive oiT peter.

13. As a composition of matter the reaction product of preferentially oil-soluble calcium petroleum suli'onate with one molecular proportion of a metal polysulfide selected from the alkali and alkaline earth metal polysulfides, said reaction product being prepared by mixing together a concentrate in mineral oil of said first named metal compound and an aqueous solution of said polysulflde and heating the mixture to a temperature ranging between 250 and 325 F. to complete said reaction and drive on water.

14. As a composition of matter the reaction in mineral oil oi said sulionate and an aqueous 76 product of preferentially oil-soluble calcium petroleum sulfonate with one molecular proportion of calcium polysulflde selected from the alkali and alkaline earth metal polysulfldes, said reaction product being prepared by mixing together a concentrate in mineral oil of said first named metal compound and an aqueous solution of said polysulfide and heating the mixture to a temperature ranging between 250 and 325 F. to complete said reaction and drive oil water.

GORDON W. DUNCAN. JOHN C. ZIMMER.

8 REFERENCES CITED The following references are 0! record in the tile of this patent:

5 UNITED STATES PATENTS Number Name Date 2,202,394 Morway May 28, 1940 2,222,482 Hagge et a1 Nov. 19, 1940 10 2,349,785 Faust May 23, 1944 McNab et a1 Apr. 15, 1947