US2710837A

US2710837A - Lubricating compositions

Info

Publication number: US2710837A
Application number: US110455A
Authority: US
Inventors: Paul R Mccarthy
Original assignee: Gulf Research and Development Co
Current assignee: Gulf Research and Development Co
Priority date: 1949-08-15
Filing date: 1949-08-15
Publication date: 1955-06-14
Anticipated expiration: 1972-06-14

Description

United States I Patent' OfiFice LUBRICATING COMPOSITIONS No Drawing. Application August 15, 1949, Serial No. 110,455

13 Claims. (Cl. 25240.7)

This invention relates to improved lubricating compositions and, more particularly, to the class of lubricants existing as plastic solids or jellies.

Compositions having good mechanical and lubricating properties over a wide temperature range can be prepared by dispersing compounds of bentonite with organic bases in an oil. These compositions, however, do not protect metal surfaces against rusting.

I have discovered that organic bentonite-containing lubricants can be improved particularly with respect to their anti-rust characteristic without adversely aifecting other desirable characteristics by incorporating in these lubricants a metallic soap. Thus, I have found that a dispersion of a metallic soap and a compound of a bentonite and an organic base in an oil results in a lubricant having improved anti-rust characteristics and good mechanical and lubricating properties over a wide temperature range. I have found that a metal coated with a lubricant comprising a dispersion of a metallic soap and a compound of a bentonite and an organic base in an oil can be protected against rusting for prolonged periods of time even in humid atmospheres.

In compounding the compositions of the present invention, various compounding and blending procedures may be used. For example, the bentonite compound may be added to a soap base grease, or the soap may be added ate a bentonite lubricant, or the soap, bentonite compound and oil may be mixed together at the same time. If an oxidation inhibitor is employed it is advantageously added to the oil before either the soap or the organic bentonite compound is dispersed in the oil.

The mineral oil ingredient in the compositions provided by this invention may be any of the hydrocarbon oils of lubricating grade, such as customarily used in compounding greases. The oil may be a refined or semirefined paraffinic-, naphthenic-, or asphaltic-base oil hav ing a viscosity of about 50 to 4000 SUS at 100 F. If desired, a blend of oils of suitable viscosity may be employed instead of a single oil, by means of which any desired viscosity within the range of 50 to 4000 SUS at 100 F. may be secured. The viscosity of the oil has little efiect on the dropping point of the compositions,

but more viscous oils produce compositions having greater stickiness and adhesive properties than do the lighter oils. The oil content of the compositions prepared according to this invention may comprise about 70 to about 95 per cent or more by weight of the total composition. The particular oil as well as the exact amount of oil employed depends upon the characteristics desired in the final composition.

The soaps which can be employed in the compositions of the invention include the metallic soaps of the fatty acids, such as the aluminum, zinc, magnesium, lead, calcium, sodium, barium, lithium and strontinum soaps of stearic, palmitic, oleic, linoleic acids, and the like. In general, the soap content comprises between about 2 and about per cent by weight of the total composition.

The amount of soap employed in any particular instance is sufiicient to substantially inhibit the rusting of metal surfaces in contact with the lubricant. The weight ratio of soap to the bentonite compound may vary over wide limits. The ratio of soap to bentonite will change depending upon the amount of soap required to obtain the desired antirust characteristic.

The bentonite compounds employed in accordance with the invention are compounds composed of a montmorillonite mineral in which at least a part of the cation content of the mineral has been replaced by an organic base. Clays that swell at least to some extent on being contacted with Water and contain as a primary constituent a mineral of the group known as montmorillonites are generally referred to as bentonites. Such clays, which contain exchangeable alkali metal atoms either naturally or after treatment, constitute the raw materials employed in making the bentonite-organic base compounds used in the compositions of this invention. So far as known,

ll naturally occurring montmorillonites contain some magnesium and certain of them, as exemplified by Hector clay, contain. such a high percentage of magnesium that they largely have magnesium in place of the aluminum content characteristic of the more typical montmorillonites.

The bentonite-organic base compounds are preferably prepared as described in U. S. Patent No. 2,033,856, issued March 10, 1936, by bringing together the bentonite and the organic base in the presence of aqueous mineral acid to efiect base exchange. The organic bases should preferably be titratable with mineral acids. Among these reactive bases are many alkaloids, and cyclic, aliphatic, and heterocyclic amines. The bentoniteorganic base compounds used in preparing the lubricating compositions of this invention are preferably those prepared by bringing together a bentonite clay and such organic bases as aliphatic amines, their salts, and quaternary ammonium salts.

Examples of such amines and salts are: decylamine, dodecylamine, tetradecylamine, hexadecylamine, octadecylamine, hexadecyl ammonium acetate, octadecyl ammonium acetate, dimethyldioctyl ammonium acetate, dimethyldidodecyl ammonium acetate, dimethyldodecylhexadecyl ammonium acetate, dimethyldicetyl ammonium acetate, dimethylhexadecyloctadecyl ammonium acetate, dimethyldioctadecyl ammonium acetate, and the corresponding chlorides and quaternary ammonium chlorides. The organic bases emplcyed should be such as to impart substantial organophilic properties to the resulting compounds. The preferred bentonite compounds are prepared from quaternary ammonium compounds in which the N-substituents are aliphatic groups containing at least one alkyl group with a total of at least 10 to 12 carbon atoms. When aliphatic amines are used they preferably contain at least one alkyl group containing at least 10 to 12 carbon atoms.

The amount of bentonite compound used may vary over wide limits depending upon the particular oil with which the bentonite compound is to be blended and upon the properties desired in the final lubricating composition. While as much as 20 per cent by weight of the total composition may comprise the bentonite compound, I prefer to use smaller amounts, that is, in the order of about 3 to 10 per cent by weight. It should be understood, however, that depending upon the consistency of the composition desired and upon the soap content of the composition less than 3 per cent or more than 10 per cent of the bentonite compound may be employed. When a bentonite compound is mentioned, it is understood, of course, that one or more of such compounds is intended.

In some instances, as when using short or single chain aliphatic amine bentonite compounds for example, dispersion of the organic bentonite compound in the oil can Patented June 14, 1955 be facilitated by the use of one or more solvating agents. Suitable solvating agents are polar organic compounds such as organic acids, esters, alcohols, ethers, ketones, and aldehydes, especially low molecular Weight compounds of these classes. Examples of suitable solvatin-g agents are: ethyl acetate, acetic acid, acetone, methyl alcohol, ethyl alcohol, benzoyl chloride, butyl stearate, cocoanut oil, cyclohexanone, ethylene dichloride, ethyl ether, furfural, isoamyl acetate, methyl ethyl ketone, and nitrobenzene. In cases where the use of a solvating agent is desirable for effecting more rapid and more complete dispersion of the organic bentonite compound in the oil, ordinarily only a relatively small amount of such agent may be necessary. However, as much as about 50 percent by weight based on the amount of the bentonite compound can be used.

Instead of expressing the metallic soap and the hentonite compound in amounts based upon the weight of the total com-position, the amounts of these constituents can be expressed in terms of their relative proportions. I have disclosed hereinabove that the amount of the bentonite compound corresponds to about 3 to about 20 per per cent by weight based on the weight of the entire lubricant and that the amount of the metallic soap corresponds to about 2 to about 10 per cent by weight of the lubricant. Thus, the ratio of the bentonite compound to metallic soap in the compositions of the invention ranges from about 3: 10 to about 20:2. When the bentonite compound to metallic soap ratio of about 3:10 is converted to per cents, one obtains about 23 per cent bentonite cornpound to about 77 per cent soap. When the bentonite compound to metallic soap ratio of about 20:2 is similarly converted, one obtains about 91 per cent bentonite compound to about 9 per cent metallic soap. Thus, the proportions of the bentonite-organic base compound to the metallic soap of a fatty acid range from about 23 to about 91 per cent of said bentonite compound to about 77 to about 9 per cent of said metallic soap of a fatty acid.

When it is desired to produce compositions having improved oxygen stability, I advantageously employ a small amount of a diaryl amine. As examples of some of the diaryl amines which may be used in the compositions of this invention may be mentioned diphenylamine, phenyl alpha naphthylamine, phenyl beta naphthylamine, alpha alpha, alpha beta, beta beta dinaphthylamines, and the like. Other diaryl amines as well as their derivatives wherein one or more hydrogen atoms on one or both of the aromatic nuclei are replaced by a substituent group may be used. The substituting group may, for example, be one selected from the class of aryl, alkyl. amino, aryloxy and alkyloxy radicals, so long as the presence of the substituent does not render the diaryl amine insoluble in oil, or soluble in water or otherwise adversely affect the effectiveness of the diaryl amine. The amount of the diaryl amine employed will depend to a large extent upon the severity of the conditions to which the composition is subjected, as well as the particular diaryl amine used. For instance when the composition is subjected to prolonged use under oxidizing conditions, such as under extreme temperature and pressure, the diaryl amine requirement will be much greater than when relatively mild operating conditions are encountered. Generally, however, the amount of the diaryl amine employed is between about 0.1 and 1.5v per cent by weight based upon the weight of the total composition. In any case, an amount sufficient to substantially inhibit oxidational deterioration is employed.

The advantageous anti-rust properties of the compositions of the present invention as compared with a similar composition containing no metallic soap can best be shown in tabular form. In preparing the compositions listed in the following table, soap base greases containing known amounts of the various metallic soaps were added to a lubricating oil having a viscosity of 255 SUS at 100 F. and containing phenyl alpha naphthyl- A1 4. amine. The greases were added in amounts such that the total metallic soap content of the finished lubricant would be about 5 per cent by weight. The oil and the metallic soap greases were stirred until a homogeneous mixture resulted. Dimethyldicetyl ammonium bentonite was then added to the mixture and the Whole was stirred until the bentonite compound was thoroughly dispersed. The resultant mixture was then milled twice employing a Premier Colloid mill set at 0.002" clearance between rotor and stator.

Composition, Parts by Wt. A B C D E F Oil 85 85 85 85 85 85 1 Badly rusted.

2 Very slight rusting.

It is apparent from these results that the anti-rusting properties of a lubricating composition comprising a dispersion of a metallic soap and a compound of a bentonite and an organic base in an oil are greatly improved over a similar composition containing no metallic soap. The oil separation characteristic was only slightly modified and the oxygen stability was substantialy unchanged. All of the above compositions had dropping points above 400 F. After 1000 hours of service, composition A bad dried out somewhat, whereas compositions B to F, inclusive, were not dried out. Compositions B to F, inclusive, gave satisfactory lubrication when tested in accordance with Army-Navy Specification Method AN-G-25 wherein a 204 bearing packed with 3 grams of lubricant was run at 10,000 R. P. M. at 250 F. for 1000 hours.

While this invention has been described with reference to specific details and examples of the production and properties of the compositions of my invention, it is to be understood that the invention is not intended to be limited to such details and examples, except as recited hereinafter in the appended claims.

I claim:

1. A lubricant comprising a dispersion of a metallic soap of a fatty acid and a compound of a bentonite and an organic nitrogen base in a mineral lubricating oil, wherein said metallic soap is present in said lubricant in an amount corresponding to about 2 to about 10 per cent by weight of the lubricant and wherein said bentonite compound is dispersed in said oil in an amount sufiicient to produce a lubricating base having the consistency of a grease.

2. An improved lubricant comprising a dispersion of a metallic soap of a CNS-C18 fatty acid and a compound of a bentonite and an organic nitrogen base in a mineral lubricating oil, wherein said bentonite compound is present in said lubricant in an amount corresponding to about 3 to about 20 per cent by weight of the lubricant and wherein said metallic soap is present in said lubricant in an amount corresponding to about 2 to about 10 per cent by weight of the lubricant.

3. An improved lubricant comprising a dispersion of a metallic soapof a Cis-Cra fatty acid and a compound of a bentonite and an organic nitrogen base in a mineral lubricating oil, wherein said bentonite compound is present in said lubricant in an amount corresponding to about 3 to about per cent by weight of the lubricant and wherein said metallic soap is present in said lubricant in an amount corresponding to about 2 to about 10 per cent by weight of the lubricant.

4. An improved lubricant comprising a dispersion of a metallic soap of a C16-C18 fatty acid and dimethyldicetyl ammonium bentonite in a mineral lubricating oil, wherein said bentonite compound is present in said lubricant in an amount corresponding to about 3 to about 10 per cent by weight of the lubricant and wherein said metallic soap is present in said lubricant in an amount corresponding to about 2 to about 10 per cent by weight of the lubricant.

5. An improved lubricant consisting of a uniform mixture of about 70 to about 95 per cent by weight of a lubricating oil, about 3 to about 20 per cent by Weight of a compound of a bentonite and an organic nitrogen base, about 2 to about 10 per cent by Weight of a metallic soap of a Cis-Cm fatty acid, and about 0.1 to 1.5 per cent by weight of a diaryl amine.

6. An improved lubricant consisting of a uniform mixture of about to about 95 per cent by weight of a lubricating oil, about 3 to about 20 per cent by weight of dimethyldicetyl ammonium bentonite, about 2 to about 10 per cent by weight of a metallic soap of a Clo-Cm fatty acid, and about 0.1 to 1.5 per cent by Weight of a diaryl amine.

7. An improved lubricant consisting of a uniform mixture of about parts by weight of a lubricating oil, about 10 parts by weight of dimethyldicetyl ammonium bentonite, about 5 parts by weight of a metallic soap of a GIG-C18 fatty acid, and about 0.5 part by weight of phenyl alpha naphthylamine.

8. A lubricant comprising a dispersion of a metallic soap of a fatty acid and a compound of a bentonite and an organic base in a mineral lubricating oil, the proportions of the bentonite-organic base compound to said metallic soap of a fatty acid ranging from about 23 to about 91 per cent of said bentonite-organic base compound to about 77 to about 9 per cent of said metallic soap of a fatty acid.

9. A lubricating composition comprising a dispersion of a metallic soap of a fatty acid and a compound of a bentonite and an organic base in a petroleum lubricant, the proportions of the bentonite-organic base compound to said metallic soap of a fatty acid ranging from about 23 to about 91 per cent of said bentonite-organic base hibiting the rust-producing properties of the modified montmorillonite, the proportions of modified montmorillonite to said metallic soap ranging from about 23 to about 91 per cent of said modified montmorillonite to about 77 to about 9 per cent of said metallic soap.

11. A lubricating composition of a petroleum lubricant, a montmorillonite modified by an organic cation, and a metallic soap of a long-chain fatty acid whose saltforming metal is selected from the group consisting of lithium, sodium, calcium, barium, and strontium, said metallic soap having the characteristic of improving the lubricity and inhibiting the rust-producing properties of the modified montmorillonite, the proportions of the modified montmorillonite to said metallic soap ranging from about 23 to about 91 per cent of said modified montmorillonite to about 77 to about 9 per cent of said metallic soap.

12. A lubricating composition of a petroleum lubricant, a montmorillonite modified by an organic cation, and a metallic soap of a long-chain fatty acid which contains a straight chain of at least eight carbon atoms and whose salt-forming metal is selected from the group consisting of lithium, sodium, calcium, barium, and strontium, said metallic soap having the characteristic of improving the lubricity and inhibiting the rust-producing properties of the modified montmorillonite, the proportions of the modified montmorillonite to said metallic soap ranging from about 23 to about 91 per cent of said modified montmorillonite to about 77 to about 9 per cent of said metallic soap.

13. A lubricating composition of a petroleum lubricant, a montmorillonite modified by an organic cation, and a long-chain organic salt gelator which contains a straight chain of at least eight carbon atoms and whose salt-forming metal is selected from the group consisting of lithium, sodium, calcium, barium, and strontium, said organic salt having the characteristic of improving the lubricity and inhibiting the rust-producing properties of the modified montmorillonite, the proportions of the modified montmorillonite to said organic salt gelator ranging from about 23 to about 91 per cent of said modified montmorillonite to about 77 to about 9 per cent of said organic salt gelator.

References Cited in the file of this patent UNITED STATES PATENTS 2,033,856 Smith Mar. 10, 1936 2,248,636 Marsden July 8, 1941 2,260,625 Kistler Oct. 28, 1941 2,355,009 Morway et al Aug. 1, 1944 2,374,565 Roden Apr. 24, 1945 2,421,672 Wilson June 3, 1947 2,436,655 Rhodes Feb. 10, 1948 2,531,440 Jordan Nov. 28, 1950 OTHER REFERENCES Polar-type Rust Inhibitors, by Baker et al., Ind. & Eng. Chem., vol. 40, pg. 2338 (December 1948).

Claims

1. A LUBRICANT COMPRISING A DISPERSION OF A METALLIC SOAP OF A FATTY ACID AND A COMPOUND OF A BENTONITE AND AN ORGANIC NITROGEN BASE IN A MINERAL LUBRICATING OIL, WHEREIN SAID METALLIC SOAP IS PRESENT IN SAID LUBRICANT IN AN AMOUNT CORRESPONDING TO ABOUT 2 TO ABOUT 10 PER CENT BY WEIGHT OF THE LUBRICANT AND WHEREIN SAID BENTONITE COMPOUND IS DISPERSED IN SAID OIL IN AN AMOUNT SUFFICIENT TO PRODUCE A LUBRICATING BASE HAVING THE CONSISTENCY OF A GREASE.