US2394790A - Greases - Google Patents

Description

ew-r d x UNITED STATE causes Hubert J. Liehe, Hammond, lnd., assignor to 'Standard Oil Company,

ration of Indiana Chicago, 111., a corpo-bv No Drawing. Application May 29, 1942,

lSerial No. 445,076

1': Claims. (cl. ass-33.2)

The present invention relates to improvements in greases and more particularly to relatively low soap-content greases of the type of ball bearing greases, mine loader greases and other anti-friction bearing greasesand to the method of preparing the same. l I

An object of the invention is to provide ,a relatively low soap-content grease of the type of ball bearing grease, mine loader grease, etc., which further object of the invention isto provide a grease of the type of ball bearing grease which is stable against oxidation. Other objects and advantages of the invention wfll become apparent from the following description .thereof.

I have discovered that the foregoing objects can be attained by incorporating in relatively low soap-content greases, of the type of ball bearing greases and similar anti-friction bearing greases, relatively small amounts of sulfonic soaps, preferably the soaps of preferentially oil-soluble sulfonic acids obtained in the treatment of mineral oils with strong I sulfuric acid. Greases of the type herein referred to contain from about 2% to about 25% of an-alkali metal soap or mixhn-es of alkali metal soaps and an alkaline earth soap of fatty materials such as fats or fatty acids.

Thus, the grease may be prepared, for example. with sodium, potassium or lithium soaps of fats or fatty acids, preferably the sodium soap, or mixtures of such soaps and an alkaline earth soap, such as for example soda-lime soaps. Fats or fatty acids such as tallow, Standard Fatty Acids, stearic acid, animal fatty acids and the like are suitable materials from which to prep re the aforementioned soaps, although I prefer to employ saturated fatty acids such as stearlc acid.

In order to obtain the above-mentioned objects it is essential 'to incorporate in the grease a small amount namely from about 0.25% to about 5% of a suli'onic acid soap. The sulfonic acid soaps which are particularly well adapted for this particular grease are the'soaps of preferentially-oilsoluble sulfonic acidsobtained-in the process of treating petroleum oils, particularlyviscouspetro-x leum oil stocks. with concentratedv or fuming sulfuric acid. In the treatment of petroleum oils with concentrated or fuming sulfuric acid -there are. obtained two layers, an acid sludge layer containing preferentiallywater-soluble sulfonic acids which because of their characteristlc greenish color are'known in the art as v green acids, and an upper oil layer which contains the preferentially oil-soluble su lfonicacids which have a reddish brown co'lor and arereferred to in the petroleum refining art as mahogany acids. After the acid sludge is removed the acid treated oil layer is then treated with a neutralizing agent v such as an alkali metal hydroxide, for example sodium hydroxide or potassium hydroxide, preferably the former, whereby the sulfonic acids in said oil layer are converted to the corresponding soaps which are then separated from the oil by means of suitable solvents such as for example alcohol. Alkaline earth soaps such as for example calcium, barium, magnesium soaps and the heavy metal soaps of these sulfonic acids can be obtained by reacting the mahogany acids with an hydroxide or oxide of the desired alkaline earth metal. The metal soap can also be obv tained by double decomposition using alkali metal soap and an alkaline earth salt.

While the scans of preferentially oil-soluble sulfonic acids derived from treatment of viscous petroleum oils with fuming sulfuric acid can be suitably employed, I have obtained especially good results by employing the soaps of preferentially oil-soluble sulfonic acids derived from a particular sulfuric acid treatment of petroleum oil distillates, namely the soaps of the preferentially oil-soluble sulfonic acids derived by treating petroleum distillates of from about '10 seconds to about 500 seconds or higher and preferably from about 200 seconds to about 400 seconds Saybolt ,Universal at 100 F. with from about 6 pounds to about 9 pounds andpreferably from about '1 pounds to about 8 pounds of concentrated sulfuric acid,-particularlyf1nning sulfuric acid per gallon of oil.

The method of obtaining these desirable soaps of preferentially oil-soluble sulfonic acids derived frompetrolemn oils is illustrated by the following example:

The petroleum oil distillate drawn, the next one-half poimd of fuming sulhaving Saybolt' Universal viscosity'at I". of from about 200 2 .iuricacidisaddedtotheoil. Thetemperature oftheoil beforethefumingacidis added thereto ing oil-soluble sull'onic acids dissolved therein, is

neutralized with a solution of sodium hydroxide. The aqueous alkali solution is then separated from the oil solution containing dissolved therein sodium soap of sulfonic acids and the latter then separated from the oil by extraction with alcohol of about 60% strength. The alcohol layer contalning dissolved sodium sulfonates is then separated from the oil and subsequently distilled to recover the alcohol'and water. The sulionic soap obtained in this manner contains from about 30% to about 60% sodium sulionate, from about 30% to about 60% oil, from about 1% to about water, and up to 10% of inorganic salts which may be removed b the procedure hereinafter described.

'lhe above procedure may be modified after the acid sludge is removed from the acid treated oil. The oil containing dissolved sulfonie acids is extracted with about 60% alcohol to remove the sulfonic acids which may then be neutralized with sodium hydroxide and subsequently freed of the alcohol by distillation.

The crude soaps of these preferentially oilsoluble suli'onic acids obtained by the procedure described above may be freed of inorganic salts by purification. This purification is preferably parts of 50% orhigher strength alcohol, preferably alcoliol of 60 to '70% strength, and allowing the salts to settle while maintaining the mixture within the temperature range of 130 to 175 F., preferably 155 to 165 F. When the salts have settled the supernatant alcohol-soap layer is separated and the alcohol is recovered by conventional distillation procedure. The crude soaps can also be purified by extraction with mixtures ot'a petroleum solvent such as naphtha and alcohol of from about 10% to about 45%, preferably 40% concentration. f

Sulionates can also be obtained by treating petroleum oils with $03, SOzCla, or with a mixture of gaseous SO: andClz.

Greases of the present invention are suitably Pounds Single pressed stearic acid 3.1 Soda mahogany soap 0.9 Dry caustic soda.-. 0.52 SAE 50 oil a 16.3 SAE 10 oil stock. 79.5 The finished grease had the following composition:

Per cent Soda soap of stearic acid. 3.3 Soda mahogany soap (oil-free basis) .4 Mineral nil 96.

Example II A ball bearing grease having the following for-- mula:

Pounds Single pressedstearic acid 13.6 Soda mahogany soap 4.0 Dry caustic soda. 2.25 I SAE 50 oi 13.8 SAE 10 oil stock 67.5

' This grease which has the following composition: Per cent Soda soap oi. stearic'-acid---.' 14.6 Soda mahogany soap (oil-free basis) 1.6 Oil. 83.8

aeoavao is d. Thus, whllei prefer to use a mineral oil having a viscosity of about 300 seconds Saybolt Universal at E, mineral oils of 60 secgreases made in accordance with the present invention.

Example I A soft smooth mine loader grease was prepared having the following formula:

has a low penetration difi'erential, a smooth struc- Penetration at w r. Dm 'r. c. c. m Grease Structure gg Doing 1 Unwol'ked Worked o 77 200 250 No. 1 Smooth- 261 280 19 382 can 400 zoo zoo 240 N0. 2. Short flbl'fl.-.-.. 151 283 132 363 700 580 400 204 No.3. ..do........;.. as 334 121 an 500 388 290 we I Torsion Toohud those coming within the following general formula:

The choice of oil used will be largely determined by the nature of the service for which the grease cone consistometer test descrfced in the on a Gas Journal, :1. 40 (March so. ma). p e as.

The above data show that greases of the present invention are superior to conventional antifriction greases inthat the former have a smoother structure, have lower diiferentials between the unworked and worked penetration.

have higher drop points, and flatter temperatureconsistency curves. I

, Example Ill, A- mixed soda-lime soap grease having a com position of a a Per cent Soda-lime stearic acid soap 11.2 Soda mahogany soap (oil-free basis) 1.4 Oil 87.4

was prepared from the following-formula:

- Pounds Single pressed stearic acid 10.4 Hydrated lime 0.2 Dry caustic soda 1.6 Soda mahogany soap 3.4 SAE 50 nil v 16.60 SAE 10 oil stock 69.60

The soda mahogany soap in the above formu las was 40% soda mahogany soap and 60% oil. The greases of Examples II and III before filling were stirred cold in the mixer to give a very smooth grease without any substantial loss in consistency. The low soap content grease of Example I was filled hot without workinpin the mixer.

-In preparing greases of the hereindescribed type the desired amount of fatty material'and the sulfonic soap are charged to the grease mixer and sumcient oil added to make a base containing from about 40% to about 50% oil and from about 50% to about 60% soap. The mix is then heated to 225-2'35 F. and a saponifying agent, for example caustic soda, in a 48 Baum solution, is then gradually added in an amount sufficient to react with all of the fatty material and leave approximately 1% excess caustic in the base. The temperature is maintained at about 225 F. to 240 F. until the base becomes heavy, and the temperature then gradually increased to about 280 F. to 300 F. and maintained at this temperature until the base becomes very short, heavy and plastic; Heating of the mix is then stopped and additional 011 graded in the mixture while the temperature drops to about 250 E,

which temperature is maintained during the remainder of the grading-in step. When the grease has been adjusted to the desired consistency heating is discontinued and water introduced into the kettle Jacket to cool the mixture as rapidly aspossible, and stirring continued until the mix ture becomes smooth and of the desired texture. In the case of mixed soap greases such as soda lime soap grease, thelime, for example, is added inthe early stages and allowed to react with the of the mixture is gradually lowered from 250 1"."

to about 160 F. while the oil is being graded in.

If desired the sulfonic acid soap can be formed insitu by using sulfonic acid and neutralizing in the mixer simultaneously with the preparation of the fatty soap base.

Greases'made in accordance with the present invention may. have added to them small amounts, namely from about 0.01% to about 2.0% of various addition agents to impart there to certain desired properties. For example the grease may contain a pour point depressor, oxidation inhibitor, oillness agent and/or other. types of additives. Oxidation inhibitors especial-,- I 1y well adapted for use in the hereindescrlbed greases are polyamines, such as triethylene 'te't ramine, ,and the neutralized reaction products or"; as lass-mu; tel:

I erably an olefinpolymexgparticularly a mono.

olefin polymer havinga molecular weight within the range of from about 150 to about 50,000 or 10,000, such as isobutylene polymer. I

The phosphorus sulfide-olefin polymer reaction product may be obtained by reacting a phos- 'phorus sulfide such as P253, P235, P457, P433, etc.; preferably Pass, with an olefin polymer of the type herein described at a temperature of from .about 200 F. to about 500 F., and preferably from about 200 F. to about 400 F. It is advantagous to maintain a non-oxidizing atmosphere, such as, for example, an atmosphere of nitrogen, above the reaction mixture. From about 1%to about 50%, and preferably'from about 5% to olefin polymer reaction product is then neutralan oxide,.or a carbonate of an-alkali or of an alkaline earth metal or with ammonia, and preferably with potassium hydroxide. This neutralization may be carried out by contracting the phosphorus sulfide-polymer reaction product,

either as such or dissolved in a suitable solvent, such as naphtha, with a solution of the neutralizing agent, for example, potassium hydroxide dissolved in alcohol. The neutralization may also be accomplished by adding the dry neutralizing agent, such as KOH, NaOH, NazCOa. IKHCOa, CaO, or dry ammonia to the phosphorus sulfide-polymer reaction product, preferably at an elevated temperature of from about 100 F. to about 400 F., preferably in a non-oxidizing atmosphere.

i The neutralized product, as aforesaid, may be, further treated with a salt of a heavy metal to obtain a heavy metal derivative thereof.

The effectiveness of the above additive in grease is demonstrated by the following data obtained in the'Norma-Hofi'man Bomb Test, which 5 is described in Product Engineering for June,

1936. The tests were made with 20 gram sampics at 210 F. for hours with an initial pressure of pounds.

' Increase Sample Soap Additive figgf'fgi g ggg 1 sample .1 Percent Na steemte Nona... 7.2 7 1,-8' N ne... a1 1.0

0.5 "1.4 foxs" Y Na steorste; 70 "1"'r"" Nasulfonaten; 7

I Additive used was a neutrslized'reactlon, product of phosphorus,

pentasulilde and an isobutyle'ne polymer. 7

1s darker and heavier thsnthe original test sample .more and preferably from about 500 to about I phorus sulfide that will completely react with filtering or by diluting witha solvent such as ized with a suitable alkali such as a hydroxide.

" At the completion of the tests sanitie'sogi was I slightly heavier and darker than the original and Samples 4 and 5 showed substantially no change. Although the invention has been described in connection with certain specific examples and embodiments thereof, it is to be understood that these are by way of example and not by way of'limitation, and the invention is not to be limited thereby except insofar as defined by the scope of th appended claims.

I claim:

1. A low soap-content grease of the type suitable for ball bearing grease comprising from about 2% toabout 25% of a soap selected from the class consisting of an alkali metal soap of a saturated fatty material and an alkali metal-alkaline earth 10. A stablegrease as described in claim a in which the oxidation inhibitor is the neutralized reaction product of a phosphorus sulfide and a hy- I butylene polymer.

mixed soap of a saturated fatty material, a major portion of which is the alkali metal soap, awmall amount, not greater than about 5%, sufilcient to produce a smooth consistency-stable grease, ofan oil soluble soap of a sulphonic acid of the type derived from petroleum oils, and mineral oil.

2. A soft, smooth, low soap-content grease of ing from about 2% to about 25% of an alkali metal soap of a saturated fatty material, from' about .25% to about 5% of a preferentially oil- I fatty material, from about .25% to about 5% of an alkali metal soap of sulfonic acid of the type derived from petroleum oils and mineral oil.

4. A grease as described in claim 3 in which the alkali metal soap of the fatty material is the soda soap and the alkali metal soap of sulfonic acid is the soda soap of sulfonic acid.

5. A low soap-content grease of the type suitable for ball bearing grease comprising from about 2% to about 25% of an alkali metal soap of a saturated fatty material, from about 0.25% to about 5.0% of a perferentially oil-soluble alkaline earth soap of a petroleum sulfonic acid and mineral oil.

6. A low soapcontent grease of the type suitable' for ball bearing greases comprising from about 2 to about 25% of an alkali metal-alkaline earth mixed soap of saturated fatty material, a major proportion of which is the alkali metal soap, a

1 ,small amount, not greater than-about 5%, sufii- "-c'ient to produce a smooth consistency-stable grease, of a petroleum sulphonic acid soap, and

mineral oil.

'7. A grease as described in claim 6 in which the mixed soap of the fatty material is the sodalime soap of stearic acid and the sulfonic'acid.

. 0 an alkali metal soap of a saturated fatty ma- 2 rial and an alkali metal-alkaline earth mixed soap of a fatty saturated material, the major proportion of which is the alkali 'metal soap, from about 0.25% to about 5.0% of a preferentially oilsoluble soap of a sulfonic acid or the type derived from petroleum oil, from about. 0.01% to about.

' 2.0% of an oxidation inhibitor and a mineral oil.

- the type suitable for ball bearing grease comprisdrocarbon.

11. A grease as described in claim 9 in which the oxidation inhibitor is the neutralized reaction product of a phosphorus sulfide and an olefin poly mer.

12. A grease as described in claim 9 in which the oxidation inhibitor is the neutralized reaction product of phosphorus pentasulfide and an iso- 13. A grease as described in claim'9 in which the oxidation inhibitor is a polyamine.

14, A grease as described in claim 9 in which the oxidation inhibitor is triethylene tetramine.

15. The method of preparing a low soap-content grease having a low penetration difi'erential, a smooth structure, resistance to oil leakage at elevated temperatures and stable against oxidation,

comprising mixing a saturated fatty material, an oil soluble soap of sulfonic acid of the type derived from petroleum oil and sufllcient mineral oilto make a base containing from about 40% to about oil and from about 50% to about soap, heating the mixture to a temperature of about 225 F. to 235 F., adding a saponifying agent selected from the group consisting of an alkali metal basic compound and a mixture of an alkali metal basic compound and an alkaline earth basic compound, the major quantity of which is the alkali metal basic compound, in an amount sufficient to react with all of the fatty material and leave approximately 1% excess alkaline material in the base, maintaining the temperature atabout 225 F. to 240 F. until the base becomes heavy and gradually increasing the temperature to about 280 -F. to about 300 F. and maintaining the mix ture at said last mentioned temperature until the base becomes short, heavy and plastic, grading in a mineral oil in an amount suflicient to reduce the soap content of the grease to not less than about 16. Tire method of preparing a low soap content soda-lime soap grease comprising mixing together stearic acid, soda mahogany soap and sufficient oil I to make a soap base containing from about 40% to about 50% mineral oil and from about 50 to about 60 soap, heating the mixture to atemperature of from about 225 F. to about 235 F., adding the required amount of hydrated lime to the mixture to react with the stearic acid. gradually adding a 48 Baum solution of caustic soda to the mixture in an amountsufllcient'to react with all of the remaining stearic acid and leave approximately 1% excess caustic soda in the base, maintaining the temperature at about 225 grease to not lessthan about 2% and not more than about 25% to the mixture and gradually reducing the temperature toabout 250 F. at which temperature the remainder of the oil is graded in,

rapidly cooling the graded mixture and stirrin the cooled mixture until the same is worked smooth.

17. The method of preparing a low soap-content grease comprising mixing together a saturated fatty material, an oil soluble soap of sulfonic acid of the type derived from petroleum oil and sumcient mineral oil to make a base containing from about 40% to about 50% oil and from about 50% to about 60% soap, heating the mixture to a temperature of about 225 F.-235 F., adding caustic soda in a 48 Baum solution, in an amount sufllcient to react with all of the fatty material and leave approximately 1% excess alkaline material in the base, maintaining the temperature at about 225 F. to 240 F. until the base becomes heavy and gradually increasing the temperature to about 280 F.-300 F. and maintaining the mixture at said temperature until the base becomes short,; heavy and plastic, gradually lowering the temperature to about 160 F. while grading in the oil in an amount sumcient to reduce the soap content of the grease to not less than about 2% and not more than about 25% required to obtain the desired consistency and filling said grease while at said last mentioned temperature.

- HUBERT J. LIEHE.