US2448720A - Novel greases - Google Patents

Description

Patented Sept. 7, 1948 UNITED STATE Francis JQLicata, West Caldwell, J ass ignor to Nopco Chemical Company, Harrison, corporation of New J No Drawing. 7 Original application August 14 1942, Serial No. 454,825, now Patent No.

, 2,431,760, dated Decem this application Marc This invention relates to improved aluminum base greases. I

Aluminum base greases are widely used for lubrication purposes on account of their waterproof characteristics, their heat resistance within certain limitations and their attractive appearance. However, thesegreases have certain disadvantages, notably their tendency to assume a jelly-like, rubbery texture upon heating above a certain critical temperature; their tendency towards syneresis, or bleeding out of oil in storage and use; and their somewhat granular and crumbling structure. Further, the oils contained in aluminum base greases must be of relatively high viscosity in order to form a stable grease.

Accordingly, it is an object of this invention to provide aluminum base greases which will have a smooth, unctuous and greasy texture, and which will retain this texture when heated to elevated temperatures.

Another object is to provide an aluminum base grease which will not separate oil upon standing.

Still another object is to provide an aluminum base grease in which a larger proportion of soap base may be incorporated than has hitherto been possible.

The above and other objects are attained by this invention in aluminum base greases which contain, in addition to aluminum soaps of saturated higher fatty acids, a small proportion of a barium soap of a higher fatty acid. The added barium soap serves to stabilize the colloidal structure of the grease, preventing syneresis thereof during storage and use, and restraining the tendency of the grease to assume a rubbery texture at high temperatures. Further, greases prepared according to this invention are characterized by having a smoother and more unctuous texture in comparison to aluminum base greases heretofore prepared and likewise are capable of holding a substantially greater amount of soap for a given consistency than is possible with aluminum base greases heretofore prepared. The expressions aluminum base greases and aluminum soaps as used herein are qualified in that, in each instance, the aluminum base or soap is that of an aluminum soap of a saturated higher fatty acid.

Except for the nonaluminum soap additive just mentioned, the greases of this invention will be constituted substantially the same as the aluminum base greases hitherto manufactured, containing in general between about 2% and about 15% to 20% of aluminum soaps of saturated Claims. (01. 252--36) j her 2, 1947. Divided and h 14,,1346, Serial No.

higher fatty acids, comprising essentially lubri v cating oils. The percentage of aluminum soap incorporated into the greases of this invention maybe slightly higher than in the usual aluminum base greases in view of the softening tendency of the nonaluminum soap additive. The aluminum content of the aluminum-soap may be varied between the usual limits and will generally be such that the washed ash determined upon the soapwill lie between about 4% and about 12%. Thefatty residues in the aluminum soap may be of the types customarily used in aluminum base greases, i. e., higher saturated fatty radicals on the order of palmitic, stearic, margaric, etc., radicals.

The fatty radicals in the barium soap may be any of the higher fatty acids having molecules containing upwards of 8 carbon atoms, and pref erably upwardsof 16 carbon atoms. Preferably, butnot necessarily, the fatty acids should be saturated. A list of suitable fatty acids, the barium soaps of-Which may suitably be employed in the greases-oi this invention, includes palmitic, stearic, arachidic, lauric, margaric, oleic, elaidic, erucic, and the like, fatty acids. Instead of the soapsof purefatty acids, there may be employed soaps of suitable mixed fatty radicals coming within the requirements above set forth, such as the mixed fatty radicals derivable from the animal and vegetable oils, fats and waxes such as tallow, corn oil, cottonseed oil, hydro genated fish oils, and the like. Likewise, the naphthenic acids are suitable components of the nonaluminum soaps incorporated into greases according to this invention. The mol ratio of metallic and of fatty radicals present in the said soaps may vary; in general, at least one of the valencies of the metal should be combined with fatty radicals, but a higher ratio may desirably be employed. Usually, the neutral soap will be employed.

The amount of barium soap incorporated into the grease of this invention may vary, depending on the properties desired in the final product, but in general this amount will be only a small fraction of the amount of the aluminum soap present. Roughly, the objects of this invention can be attained by the addition of from about 0.1% to about 5% of the barium soap, based upon the total weight of grease. In general, the higher the percentage of barium soap, the softer the resulting grease will be for any given percentage of aluminum soap, and advantage can be taken of this fact to add a considerably greater total amount of soaps to the grease than has heretofore been possible with aluminum base soaps.

The manner of preparing greases of this invention can. follow any conventionalv practice, this not being critical to the invention. Conveniently, the aluminum soap, barium soap,

lubricating oil and any other desired ingredients.

With the above discussion in mind, there is.

given herewith an example of a grease prepared in accordance with this invention. All parts.

given are by weight:

Example Parts Aluminum stearate (8% Washed ash) 11 Barium soap (neutral stearate) 1 Paraflin oil (100 sec. viscosity 100 F.) 88

The above ingredients were heated to 150 C. with stirring, and slowly cooled to room temperature; The resultinggrease-was soft with'a smooth texture and free from bleeding. On reheating, it melted without passingthrough the rubbery stage.

From the above, it will be seen that the greases provided by'this invention aredistinguished from similar greases heretofore prepared in that they do not become rubbery upon heating. This is highly advantageous since the greases do not-lose their lubricating properties upon overheating of the surfaces to which they are applied. Further, greases according to this invention possess a smoother and more unctuous texture than aluminum base greases heretofore prepared. Still further, the greases of this invention may have a higher net soap content, can be made from less viscous oils without danger of bleeding out of the oil, and'exh'ibit a higher degree of water-resist- 4 ance than aluminum base greases of the prior art. Finally, greases according to this invention are highly stable in storage and use against any separation or syneresis of the oils contained therein.

This application is a division of my application Serial No. 454,825 filed on August 14, 1942, now Patent No. 2,431,760, dated December 2, 1947.

I therefore claim:

1. Alubricating grease comprising mineral oil, 2%.to 20% of an aluminum soap of a saturated higher-fatty acid and 0.1% to 5.0% of a barium soap of a higher fatty acid, the quantity of the barium soap being only a fraction of that of the aluminum soap.

2'. A lubricating grease comprising mineral oil, 2% to 20% of an aluminum soap of a saturated higher fatty acid and 0.1% to 5.0% of a barium soap of a saturated higher fatty acid, the quantity of the barium soap being only a fraction of that of the aluminum soap.

3. A lubricating grease comprising mineral oil, to 20% aluminum stearate and 0.1% to 5.0% of a barium soap of a higher fatty acid, the quantity of the barium soap being only a fraction of the aluminum soap.

4. A lubricating grease comprising mineral oil, 2% to 20% aluminum stearate and 0.1% to 5.0% of a barium soap of a saturated higher fatty acid, the quantity of the barium soap being only a fraction of that of the aluminum soap.

5. A lubricating grease comprising mineral oil, 2% to 20% aluminum stearate and 0.1% to 5.0% barium stearate, the quantity of the barium soap being only a fraction of that of the aluminum soap.

FRANCIS J. LICATA.

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

UNITED STATES PATENTS Number Name Date 1,625,969 Willock et al Apr. 26, 1927 2,266,544 Freuler- Dec. 16, 1941 2,332,247 Morway et a1 Oct. 19, 1943 2,379,245 Morway et a1 June 26, 1945 2,397,956 Fraser Apr. 9, 1946