US2352811A - Lubricant - Google Patents

Description

QDEJVEWQTUN July 4, 1944.

R. A. SWENSN LUBRICANT Filed June 27, 1941 2 sheets-sheet 2 Patented July 4, 1944 UNITED STATES 2,352,811 LUBRICANT Reuben A. Swenson, Hammond, Ind., assignor to Standard Oil Company, Chicago, Ill., a corporation of Indiana Application June 27,

1o claims.

This invention relates to block greases and to methods for making the same and has particular reference to greases known as driving journal compounds.

Greases of the driving journal compound type must fulfill rigid specifications due to the severe' conditions of use. It is customary in lubricating driving journals tov apply the grease in the form of a cake or block to the rotating shaft and to hold the same in place by means of a spring and follower plate. Therefore they must have "high melting points in order to retain their 'shape and consistency at elevated temperatures caused by radiated or conducted heat developed by friction between the metal surfaces. Greases of this type must remain sufficiently plastic for extended periods of time in order to insure proper lubrication of the shaft--that is to say, the grease must be highly resistant to oxidation so as not' to harden at elevated temperatures in the presence of oxygen. When a block of grease becomes o xidized and hard, lubrication of the metal parts is prevented, resulting in increased temperatures which ultimately cause c arbonization of thegrease. This carbonization causes complete failure of lubrication, and subsequent damage to the driving journal. Greases of this type must not develop oil leakage at elevated: temperatures, leaving a hard soap residue having little or no lubricating properties.

In the past certain driving journal compounds vforming the driving journal grease-that is to say, in addition to the soap usually formed during saponication of the fat. I have found that re kettle driving journal grease containing this solubilizing or plasticizing agent does not require preoxidation of the oil or'fat components prior to compounding the grease. y

The soaps which may be added in lieu of the pre-oxidation step may be such oil-soluble metal lsoaps as mahogany soap or oil-soluble naph- 4 thenates of lead, aluminum, calcium, etc.

though mahogany soap, which is the sodium soap of mahogany acids, is preferred; other metallic soaps of the mahogany acids such as potassium, calcium, barium, aluminum, iron and lead soaps and the like can be used. v

`While the term mahogany acids" is well During the preparation s 1941, Serial No. 400,024

known in the art, it is believed that a description of a method of obtaining lsuch material is desirable. In the preparation of highly refined petro1eum oils, the oils are' treated successively 5 with anumber of portions of concentrated or fuming sulfuric acid. A variety of sulfur-containing compounds are formed by the chemical reactions of .the treating operations, 'including suli'onic acids. organic esters of sulfuric acid, etc. Most of these compounds are relatively insoluble in the oil under the treating conditions, and therefore separate from the oil, together with unreacted acid, as a sludge which is separated from `the oil after each acid treatment. Some of the sulfonic acids are preferentially oil-soluble; these remain in the oil and can be removed therefrom by neutralizing the acid-treated oil with caustic soda, caustic potash or ammonia to form sulfonic acid soaps or sulfonates, and extracting these sulfonates from the oil by treatment with 50% to 80% aqueous alcoholic solutions or other suitable means. Because of the characteristic mahogany color of these sulfonates they are known as mahogany soaps and will hereinafter be referred to as such. The mahoganyv soaps mayalso be obtained by extracting the sulfuric acid treated oil prior-to neutralization with an aqueous solution of an alcohol whereby the mahogany acids are extracted from the oil, and treating the extract obtained with a neutralizing agent such as, for example, NaOH,

KOH or NHTOH, to convert'mahogany acids to-`l the corresponding mahogany soaps.

The addition of small amounts of the abovementioned soaps produces driving journal greases 40 journal compound type and new and improved methods `for preparing same.

Another object of the invention is to provide a grease of the type described having animprovedl resistance to oxidation.

Still another object of the present invention is to provide a grease having a more uniform consistency during variations in temperature A further object is to prepare a grease of the driving journal compound type which doesy not require the pre-oxidation of -the oil or fatty material.

,A still further object of the present invention is to provide an improved process whereby the time usually required for preparing this type of grease is greatly reduced. Other objects will be apparent as the description of the present invention proceeds.

In order to understand the invention more clearly reference is made to the' drawings forming a part of this specitication in which, 0 Figure 1 shows the degree of hardening o! as soaps of sulfonated animal and vegetable oils,

soaps of mahogany acids, and oil soluble soaps of naphthenic acids. These soaps may be the sodium, potassium, calcium, barium, lead, aluminum, iron and other metal soaps of the various acids mentioned above. It is particularly pointed out that these solubilizing agents do notreplace the soaps usually present in a driving journal compound, but rather are used in addition to those soaps. l

Although the specific application .of my invention is for a driving journal grease which may vary in soap content from about 30% to aboutI 60%, this method of plasticizing soda soap greases may be used in any sodium soap grease that contains from about 1% to about,60% soap in addition to lthe'plasticiaing agent itself. The amount of solubilizing agent required will depend on the particular agent chosen for this purpose and the kind and amount of soap in the grease. The amount of solubilizing agent 'may vary from about 1%,to about 20% of the total mix. i

Greases of the driving journal type according to the presentinvention are made from about 30% to about 60% fatty material, from about 5.0% toabout caustic soda, about 1% to about solubilizing or plastici'zing agent and the balance oil. The oil used may have various properties, depending on the exa-ct nature of the product desired; for instance, steam refined oil (530 F. flash), or any oil having .a viscosity of between about 150 and about 250 seconds Saybolt Universal at 210 F. can be used. The fatty by mixing together the fat and/or fatty acid, petroleum oil and solubilizing agent and heating this mixture. Following this the caustic, such as sodium hydroxide, is added and the mixture is heated further, so that the product will be in a liquid state 4for filling containers and the like. By this process considerable time is saved since it is not necessary to pre-oxidize theA oil.or the fat, and furthermore because foaming which was a serious disadvantage of the previously known processes, is avoided. In the following more detailed description of the invention reference will be made to penetration and softening time.

Penetration is an indication of hardness and consistency and in the following data it has been based on the A. S. T. M. penetration test, D 217- 38 T. Softening time, on the other hand, is an index of quality from the service standpoint and ls measured by the following described test. A cylinder of driving journal compound one-half inch in diameter and above five-eighths inch long is heated on a metal plate contained in an oil or mercury bath. The temperature of the bath is controlled to give the desired temperature at point of contact between the plate and grease sample which is subjected to the weight of an 85 gram cylinder, thus providing a pressure on the driving journal compound comparable to the pressure to which the same is subjected in actual material may consist of fats` such as blended animal fat, tallow or the like or Various fatty acids can be used in place of the fat or a mix^ ture of the two can be used. 'Ihe fatty acid may =be unsaturated, partially unsaturated or preferably saturated, such as hydrogenated sh oil fatty acid ora pitch obtained therefrom in accordance with the procedure described in U. S. Letters Patent Nos. 2,229,367 and 2,229,368. It. has been found that a combination of one of the above oils and a fat or a fatty acid, or a mixture of them together with caustic and a solubilizing agent according to the present invention produces a grease which is superior to previously known driving journal greases. Broadly, those greases made with saturated fatty acids alone are particularly resistant to oxidation, while those made sired properties of the grease. This reduced total soap content is in no small part responsible for the very ne resistance to oxidation.

Greases of the type described can be prepared eisl compounds prepared according to previously.

known processes and are submitted here for purposes of comparison With the new compounds.

' TABLE I Percentages Ex. Ex. Ex. Ex. Ex Ex. Ex. Ex. 1 2 3 4 5 6 7 B FatGllOW) 50 10 20 20 46 24.5 Fat (animalblended) 50 Fattyacid(sat'd) .L 35 20 Fatty acid (partially unsatd) 38 27 Dry Caustic (added as 48 Bxsolution) 8 8 6 8 8 8 8 6.0 Plasticizer(niahoganysoap). 6 6 12 6` 6 6 Steam refined oil (530 F.

flash) 36 36 47 38 46 39 146 246ml aano cinerstoc o'd'dt' crease at 210 F. I y xi ize o give 60% viscosity in In the following table certain penetration data are gwen as welly 'as the softening time and pressabllity of the foregoing greases:

TABLE II Penetration at 77 F.

- softening 150 ztiilixix? t P l g. ressa iilit Uncut Cut added, g. y surface surface cur weight) surface Ex. l 27 4l 4,000 Ver ood. Ex. 2 33 46 1,100 Ex. 3 20 28 42 4,000 Fair-sticky. 26 40 7, 200 Very good'.

33 48 2, 700 Fair. 34 50 5,400 Good. 34 48 400 Fair-sticky. 4l 84 400 Sticky.

An additional method of improving the plastic properties of the greases is to use a quantity of caustic slightly in excess of that theoretically required to saponify the fat. It is believed that theexcess caustic reacts partially or wholly with the small amount of slycerine which is formed in the saponiilcation of the fat. This reaction product also acts as a solubilizing or plasticizing agent. Therefore, it has been found that to of the finished grease should consist of soap from a fat such as tallow and excess caustic to react with the glycerine liberated.

With particular reference to the drawingsforming a. part of this specification, Figure 1 shows the hardening effect of increased temperatures for various periods of time on each of the examples noted above. It is evident that the products of examples 4, 5 and 6 are better, that is, superior in resistance to oxidation, to the product of example 7, and that the products of examples l and 2 are comparable to example 'I in resistance to oxidation. It will be noted that all ofthe examples are far superior to example 8. Figure 2 shows the effect of various temperatures on the consistency of the greases as measured by the penetration. It will be noted that examples 4 and 6 are vastly superior to example 7, while example 5 is only slightly less satisfactory than examples 4 and 6.

The method of manufacture of these greases is as follows: A mixer of conventional type is charged with all of the fatand/or fatty acid, petroleum oil and oil-soluble soap such as mahogany soap, and while these ingredients arebeina stirred, the mixer is heated to approximately 180 F. to 220 F., at which temperature all of the caustic such as sodium hydroxide is added -as a 48 Baume solution. The batch is heated at about 220 F. to about 230 F. until dry; then the temperature is raised as rapidly as conditions permit to approximately 500 F. for filling. 'At this temperature the batch is in a liquid state, so it can be filled into pans to solidify. Alternatively, the grease may or may not be heated to fire kettle temperaturesvof about 350 F. to about 600 F. before filling. The filling temperature is independent of the maximum processing temperature and may be varied to meet specific applications.

While the present invention has been described with particular reference to railroad driving journal greases, it may also be applied advantageously in the manufacture of mill greases and the like. Although particular reference has been made to certain preferred embodiments of the present invention, it is to be understood that these are by way of illustrationvand-not by way of limitation. The scope of the'present lnvention is to be limited only by the appended claims.

I claim:

' prises hydrogenated 1. A hard, block grease of the type employed for the lubrication of driving journals prepared from about 30 percent to about 60 percent of a fatty material, about 5 percent to about 10 percent caustic soda, about one percent to about-20 percent oil-soluble metal sulfonate derived from petroleum oil-and the balance mineral oil.

2. A hard, block grease as claimed in claim 1 wherein the balance consists of a mineral oil having a viscosity of about 250 seconds Baybolt Universal at 210 F.

3. A hard, block grease of the type employed for the lubrication of driving journals prepared from about 50 percent fatty material, about 8 percent caustic soda, about 36 percent petroleum oil and about 6 percent mahogany soap.

4. A hard, block grease of the type employed for the lubrication of driving journals, prepared from about 40 percent fatty material, about 8 percent caustic soda, about 46 percent steamrefined oil and about 6 percent mahogany soap.

5. A hard, block grease of the type employed for the lubrication of driving journals prepared from about 38 percent fatty material, about l0 percent fat, about 8 percent caustic soda, about 38 percent steam-refined oil and about 6 percent mahogany soap.V

6. A driving journal compound comprising a hard block grease prepared from about 30 percent to about percent of a saturated fatty material. about 5 percent to about 10 percent caustic soda,about l percent to about 20 percent of an oil-soluble metal sulfonate derived from petroleum oil, and the balance mineral oil having a viscosity of from about seconds to about 250 seconds Saybolt Universal at 210 F.

' 7. A driving journal compound comprising a hard block grease prepared from about 30 percent to about 60 percent of hydrogenated fish oil fatty acid, about 5 percent to about l0 percent caustic soda, about 1 percent to about 20 percent of an oil-soluble metal sulfonate derived from petroleum oil, and the balance mineral oil having a viscosity of from about 150 seconds to about 250 seconds Saybolt Universal at 210 F.

8. A hard block grease of the type employed for -lubricating driving journals which grease comprises an amount within the approximate range of 30% to 60% of an alkali metal soap of a fatty acid material and an amount within the approximate range of 1% to 20% of mahogany soap, the remainder consisting essentially of viscous lubricating oil.

9. The grease of claim substantial part of the fatty acid material comiish oil fatty acid material.

10. The grease of claim 8 wherein the amount of mahogany soap in the grease is in the general vicinity of 6%.

REUBEN A. SWENSON.

from about 150s`econds to.

8 in which at least a.`

CERTIFICATE oF CORRECTION. patent No. 2,552,811. any b., 19ML.

HEUBEN A. swE'NsoN.

It is hereby certified tha-t error appears in the printed specification ofthe above numbered patent requiring correction as follows: Page '5, second column, line 211 claim 5, for fatty material" read --fatty ac1d;

' and thft the said Letters. Patent should be read with this correction therein that the same may conform to the record of the case 1n the Patent Office.

Signed and sealedthis 22nd day of August, A. D. 19h14..'

Leslie. Frazer (Seal) l y Acting Commissioner of Patents.

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