US2457586A - Grease composition - Google Patents

Description

Patented Dec. 28, 1948 UN I T E D S TATE-S O F F I CE GREASE COMPOSITION John F. McG'r'oga'n, Philadelphia, Pa., as'sig'nor to The Atlantic Refining Company, Philadelphia, Pa., a corporation of Pennsylvania No Drawing. Application September 4, I946, SerialNo. 694,833

6 Claims. (Cl. 2523,6)

The present invention relates to improvements in calcium base grease compositions; andparticularly those which are utilizedin high temperature lubrication or under conditionswhere the parts lubricated are subject to water wash ing and/or elevated temperatures. The greases of the present invention are especially'applicablein the lubrication of thebearings of rolling mills fabricating hot or cold rolled steel sheets, strips; bars and the like, where the bearings may be water-cooled and therefore subject to thewashing action of water. The improved greases" arealso adapted in the lubrication of wheel bearings, universal joints, and other" machine parts where the use of ordinary grease is ineffective due to water solubility or low dropping point.

It is therefore an object of this invention to provide improved calcium base greases characterized by their stability at temperatures well abovethose at which the ordinary" calcium base greases are applicable, and under conditions where the ordinary soda base greases of high dropping point are ineffective due to their Water solubility.

Conventional calcium base greases are unsuitable for use at elevated temperatures since they are unstable at temperatures of the order of 200 F. to 220 F., and in many cases lubrication is required at much higher temperatures, for example, at 250 F. to- 350 F. in rolling" mill bearings.

This invention is predicated upon the fact that by compounding in' a calcium" base grease, a small amount of a lead' salt of an aliphatic monocarboxylic acid of not more than 8- carbon atoms, an improved grease is obtained which possesses not only the desirable characteristics of calcium base greases but also a stability at temperatures much in excess of those at which ordinary calcium base greases are capable of being applied.

In accordance with the present invention, there is incorporated in a calcium base grease comprising lubricating oil and calcium soaps of fatty acids, a small but sufficient amount of a lead salt of the type aforesaid to substantially increase the dropping point of the grease, as determined by the A. S. T. M. method D566-42 entitled Dropping point of lubricating greases. In general, the improved grease may comprise about to 50% by weight of calcium soaps of fatty acids, 1% to 20% by weight of lead salt, and the balance lubricating oil. Preferably the grease will comprise 10% to 30% of calcium soaps, 1% to 10% of lead salt. and the remainder mineral lubrieating oil. The calcium soaps may" be obtained by saponifying fatssuch as tallow, fish' oil, hog fat, hoss fat oleic-acid--30% stearic' acid), cottonseed oil, or lard oil with a basic compound of calcium, such aslime flour or hydrated lime, or by neutralizing saturated or unsaturated fatty acids of from 12 to 20 carbon atoms; or mixtures thereof, with lime. The consistency of the improved grease may be varied as desired by increasing or decreasing the calcium soap content, or conversely by varying the amount of lubricating oil used, the consistency being determined by the A. S. T. M. method D217.44T entitled Consistency of lubricating greases and petrolatum. The dropping point of the grease may be varied; depending upon the quantity of lead salt employed. Conventional calcium basegreases usually have dropping points between F. and 230- R, whereas theimp'roved greases of the present invention may have dropping pointsas high as 500 F'. In compounding thegrease, it is preferred to employ a lead s'alt such as lead acetate; although the lead salts of the other aliphatic monccarboxylic' acids containing up to d-carbon atoms will produce similar results, the effect being somewhat less pronounced with increase ini carbon atonr content.

The present invention may be further ill-us trated by thefollowing examples; which, from ever, are not to be construed as limiting the scopethereof.

Greases of various-soap content and' lead salt content were prepared accordingzto thefollowingv procedurewhich-represents one of several methods which may be employedin compounding the product.

About 10% of the total lubricating oil to be employed is introduced into a steam jacketed grease kettle provided with a mechanical stirrer. The oil is heated, with agitation, and the entire quantity of fat or fatty acid is added and brought into solution in the oil. A slurry of about equal parts of lubricating oil and dry lime is made up, the lime being in the amount necessary to effect saponification of the fat or neutralization of the fatty acids employed. The oil-lime slurry is then added to the oil and fat or fatty acids in the kettle and the temperature of the mixture is maintained between 200 F. and 220 F. until saponification or neutralization is complete, the entire mixture being agitated during this step. The temperature is then increased to about 250 F. to drive off water, if any is produced during the soap-forming step, and about of the lubricating oil remaining is added to the oil-soap mixture in the kettle. The mixture is thoroughly agitated, and the desired amount of lead salt is added, preferably in the form of an aqueous solution of lead acetate having an acetate concentration of about 60% to 70%. The temperature of the mixture is maintained at about 250 F. to drive off all of the water, and the remaining A of the lubricating oil is added and .thoroughly incorporated by agitation. The quantity of lubricating oil employed determines the consist ency of the product, and as pointed out hereinbefore, may be varied as desired. The hot mixture is cooled to a temperature of the order of 80 F. to 100 F. and the resulting grease is intro,- duced into suitable containers. The ingredients and the properties of the greases are tabulated below.

Ingredients, Wt. Per Cent 300 Paraffin Oil (24 grain, 305 S. U. Vis./100

F., .pour) 64.3 0 0 100 Paraffin Oil (27 gram, 100 S. U. Via/100 0 F. gem) O 31. 1 23.4 55 Malt a Oil (19 gram, 155 S. U. Vis./210

F., 30 pour) l 0 50. 8 38.3 Hog fat 12. 2 5. 7 12.0 Hoss fat 11. 9 5. 7 12. 0 Hydrated lime 3. 1. 5 4. 3 Lead acetate Pb(CzHaOz)z.3HzO 8. 1 5. 2 10.0

Properties of Product Penetration A. S. T. M. 77 F 315 400+ 298 Dropping point A. S. T. M., "F 473 390 493 Water Content N Nil Nil In the above examples, certain definite proportions of ingredients have been set forth. Such proportions may be varied considerably in order to obtain greases of difierent consistencies and dropping points. The source of the fats or fatty acids may also vary, as may the technique of compounding the ingredients. The lubricating oils may be of any desired viscosity, for example, from 50" S. U. at 100 F. to 1000" S. U. at 210 F., and may be straight run lubricating distillates or residuums, selective solvent treat- I claim: I

1. A grease composition consisting essentially of mineral lubricating oil, calcium soaps of fatty acids in an amount suflicient to impart the desired consistency to the grease, and a small quantity of a lead salt of an aliphatic monocarboxylic acid containing not more than 8 carbon atoms suflicient to increase the dropping point of said grease to a temperature between 300 F. and

2. A grease composition consisting essentially ed oils, cracked oils, hydrogenated oils, oils produced by polymerization of olefins or by alkylof calcium soaps of fatty acids, and from 1% to 20% byweight of a lead salt of an aliphatic monocarboxylic acid containing not more than 8 carbon atoms.

3. A grease composition consisting essentially of mineral lubricating oil, 10% to 30% by weight of'calcium soaps of fatty acids, and from 1% to 10% by weight of a lead salt of an aliphatic monocarboxylic acid containing not more than Scarbon atoms.

4. A grease composition consisting essentiallyof mineral lubricating oil, calcium soaps of fatty acids in an amount suflicient to impart the desired consistency to the grease. and a small quan tity of lead acetate sufficient to increase the dropping-point of said grease to a temperature betweeen 300 F. and 500 F.

5. A grease composition consisting essentially of mineral lubricating oil, 10% to 30% by weight of calcium soaps of fatty acids, and 1% to 10% by weight of lead acetate.

6. A grease composition produced by compounding together 1 'Per cent Mineral lubricating oil -80 Hog fat 5--12v Hoss fat 5-12 Lime 1.5-4.5 Lead acetate 5-10 JOHN F. MCGROGAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,197,263 Carmichael et al. Apr. 16, 1940 2,399,063 Schantz Apr, 23, 1946 FOREIGN PATENTS Number Country Date 9,973 Great Britain 1900