US2421631A - Lubricating oil - Google Patents

Description

Patented June 3, 1947 LUBRICATING OIL Bert H. Lincoln, Ponca City, Okla., and Gordon D. Byrkit, Niagara Falls, N. Y. 1

N Drawing.

15 Claims. 1

Our invention relates to lubricating oils and more particularly to improved lubricating oils of high film strength which are non-corrosive toward easily corroded bearing materials.

This is a division of our copending application Serial No. 405,213, filed August 2, 1941, now Patent No. 2,395,889, issued March 5, 1946, which, in turn is a continuation-in-part of our application Serial No. 275,488, filed May 24, 1939 (now Patent No. 2,257,750, issued October 7, 1941.)

In the development of new automotive and other types of engines, increased power and other requirements have led to the introduction of bearing metals, alloys, and mixtures which are readily attacked by oxidation products of the lubricant. Some of these newer bearin compositions are cadmium-silver, copper-lead and a1- loys of lead with alkali, and alkaline earth metals. These comparatively soft metals are corroded readily by oils which have been used for a short time in the engine. One method of overcoming this difficulty would be to use more resistant bearing compositions, and anotherwould be to use an oil which does not develop these corrosive materials during use. Still another method would be to use a lubricant containing a material which would react with and render. inert the corrosive products as rapidly as they are formed. Our invention is not concerned with the first method but with the other two possibilities. Various addends have been proposed to be added to lubricants for the purpose of inhibiting the formation of corrosive materials during use. These may be called antioxidants, since they increase the time of use before rapid oxidation begins to occur and also decrease the rate of oxidation after it has started. Various addends have also been proposed to be added to lubricants for the purpose of reacting with such corrosive materials, as may in time beformed, and removing them from the oil so that they are unable to corrode the parts being lubricated. These may be called precipitants. The present invention proposes addends combining these two capabilities in the same molecule to give an un expectedly superior activity in both respects over what would be predicted from a simply additive efiect.

Certain compounds are adsorbed or absorbed by metals forming tenacious films at the surface of metals which are able to stand high pressures. X-ray diffraction methods have shown that compounds containing highly polar molecules, that is, molecules of unsymmetrical character containing an atom or group of atoms ex- Original 1941, Serial No. 405,213. plication May 16, 1945, Serial application August 2,

Divided and this aphibiting a secondary or residual valence, tend to.

a film of the compound in which there is a regimentation of molecules oriented with respect to the surface of the metal by which they are adsorbed or absorbed.

One object of our invention is to provide a substantially non-corrosive lubricant for use with the newer, easily corroded bearing compositions. It is to be noted, however, that the improved lubricant here described is advantageously employed with all typesof bearings, since it is less corrosive during use with any of the metals commonly encountered in practice.

Another object of the invention is to provide a lubricant inhibited against oxidation during use.

A further object of our invention is to provide a lubricant containing an addend capable of reacting with or otherwise rendering inert such corrosive products as may be formed during extended use.

4 Other objects of the invention will appear in the following description.

Our invention consists of the addition to lubricants of all kinds of salts or soaps of certain sulfur-bearing acids. 'These salts may be of diverse types, and both the'anionic and cationic parts of these soaps may be varied. Thus the cations may be purely organic or purely metallic or organometallic. In introducing sulfur into the acid. radical of our salts, we have found that certain compounds rich in sulfur react with unsaturated acids to yield peculiarly effective addends for lubricating oils. By compounds rich in sulfur, we mean those containing more than 50 per cent of sulfur in their molecular composition. Examples of these reagents are phosphorus pentasulfide, phosphorus pentasulfide, phosphorus trisulfide, and alkali metal polysulfides (sodium disulfide, potassium trisulfide, and higher sulfides). These particular sulfurizing agents yield particularly effectively bound sulfur in the molecule of the sulfurized acid. The herein described salts of such su1- furized acids are extraordinary detergents and inhibitors of oxidation when addedto lubricants of all kinds. They contain no corrosive halogen and are more effective inhibitors than salts of acids containing sulfur in knownstructures such as sulfonic acids, sulfones, thioethers, heterocyclic sulfur, and the like. g

In the following examples, any of the cations may be usedwith any of the anions to form these I. Anions A. Alkali metal polysulfide-treated acids 1. Sodium pen-tasulfide treated "oleic acid 2. Sodium tetrasulfide treated linoleic acid 3. Sodium trisulfide-treatedlinolenic acid 4. Sodium 'disulfide-treatedbelaidic acid 5. Potassium pentasulfide-treated corncilaci'dS 6. Potassium trisulfide treated soy oil acids 7. Potassium tetrasulfide treated lard oil acids 8. Lithium pentasulfide-treated tungoil acids 9. Lithium tetrasulfide treated abi'etic acid Lithium trisulfide treated choliczacid A mm'ioni u m pentasulfida treated naphthenic acids -3. Phosphorus sulfide treated acids (containing phosphorus and :sulfur) 1.. Phosphorus penta sulfidetreated corn; oil acids 2. Phosphorus" trisulfide-treated;

corn oil. acids .3. Phosphorus :penta an 1 it i d e- :treated, soy OilzdGidS v4. Phosphorus: pentas u-l'f 1 detreated 'lolei'cjacid 5. Phosphorus penta s u 1 f i de treated linoleic: acid IL Cations -A-. Metallic:

l. Grouprl Lithium, sodium,;pqtassium, rubidium, cesium, copper 2. rC-lrolupz Calcium,-strontium,,bari-- .um, beryllium, =magnesium, zinc, cadmium,

These organo-metallicsoaps may have, in the organo-metallic cation an. organic radical or radical's of "the aliphatic or carbocyclic'orheterocyclic series. The metallic element of the compound maybe anyone of a number of which, the following are'representative. For convenience, we shall indi- 4 list them in accordance with their occurrence in the periodic table:

Group II Magnesium Zinc Cadmium Mercury Group III Boron Aluminum fI'hallium Group IV Silicon Tin Lead Group V Arsenic Bismuth Antimony Group VI Tellurium Selenium Some of the organo-metallicradicals which may act as cations informingthe soaps to be used are:

GroupwlI V Phenylmagnesiurn Propyl magnesium Methylzinc Cresylzinc Xylylcadmium Iso-Amylcadmium Butylmercury Mesitylmercury Nitrophenylmercury Naphthylmercury Group III Phenylboron (II) Diphenylboron (I) o-Xylylboron (II) Dipropylaluminum Diethylthallium Diphenylthallium Di-p-tolylthallium Group IV Triphenylsilicon Triphenylgermanium Di-isoamyltin Di-alpha-naphthyltini Diphenyltin Ethylphenyltin iso-Propyltin Triethyltin Triphenyltin Di-isobutyllead Diethyllead Diphenyllead Triphenyllead- Group V Ethylarsenic Diphenylantimony Di-alphanaphthylbismuth Diphenylbismuth Group VI Phenyltellurium Diphenyltellurium Triphenyltellurium Phenylselenium tached to the metalror inthe anion of the soap. an additional element, or combination-0t elements includingthe halogens sulfur, phosphorus,

76 nitrogen, or oxy en Some of the combinations of the cations with the anions are listed below, but it is obvious that all the possible combinations serve as examples of the invention when admixed with lubricating oils or greases:

.Sodium salts of sulfurized corn oil acids Aluminum salts of sulfurized beta fat Stannous salts of sulfurized corn oil acids Stannic salts of sulfurized corn oil acids Ammonium salts of sulfurized oy oil acids Triphenyltin salts of sulfurized corn oil acids Diethylthallium salts of sulfurized corn oil acids Phenylmagnesium salt of sulfurized oleicacid Nitrophenylmercuric salt of sulfurized lard oil acids 10. Diphenylthallium salt of sulfurizedsoybean oil acids Triamylammonium salts of acids Calcium salts of sulfurized corn oil acids Lead salts of sulfurized beta fat Barium salt of sulfurized oleic acid, sulfurized with sodium pentasulfide Triphenyltin salt of sulfurized oleic acid Benzyltrimethylammonium salt of sulfurized oleic acid,'sulfurized with phosphorus pentasulfide Calcium salt of sulfurized oleic acid, sulfurized with sodium pentasulfide Calcium salt of sulfurized oleic acid, sulfurized with sodium trisulfide Benzyltrimethylammonium salts of sulfurized corn oil acids, sulfurized with sodium pen- 'tasulfide 20. Triphenyltin salts of sulfurized soybean oil acids, sulfurized with phosphorus penta- While all of the above usual results described, we have found that particular emphasis should be placed on the organometallic salts of sulfur-bearing acids because they are especially effective antioxidants and corrosion inhibitors; furthermore the tin salts (metallic or organo-metallic) deserve notice as exhibiting these properties to a high degree.

The addends of this invention have a dual action in a lubricant. One action involves increased load-carrying ability and/or oiliness, while another action is directed to the stability of the lubricant. For load-carrying capacity, quantities ranging from 0.1 per cent to about 10.0 per cent must be added. As an anticorrosive agent and/or an antisludging agent, much smaller amounts must be used, ranging from approximately 0.001 to 0.1 per cent. The action of the organo-metallic compounds is specific but difiicult to understand. These compounds may be added to any type of hydrocarbon lubricants but show an unusual value in highly refined and solvent-treated lubricants.

The lubricating oil portion of the blends of our invention may be so-called mineral or hydrocarbon oils or may consist of wholly or contain only in part certain fatty oils including corn oil, soybean oil, lard oil, and the like. The blends may contain voltolized oils or synthetic oils of lubricating viscosity. Soap-thickened or otherwise thickened oils used as greases may be employed. Addends for other purposes such as pour point depressors may be present.

These compounds have varying degrees of solubility in hydrocarbon oil. In some cases, it is necessary to use a solvent for the compound or 11. sulfurized lard oil examples give the unto form colloidal suspensions of the compound in oil.

The film strength and oxidation characteristics of solid and semisolid greases may be improved by the addition of small amounts of our metallic soaps thereto. The chemical purity for use as extreme pressure addition agents is not critical. All that is important is that no corrosive contaminants be present. Mixtures of a number of these compounds may be employed.

It will be understood that'certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of our claims. It is further cbvi ous that various changes may be made in details within the scope of our claims without departing from the spirit of our invention. It is therefore to be understood that our invention is not to be limited to the specific details shown and described.

We claim:

.1. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, sufficient to stabilize said oil against oxidation, of a salt of a sulfurized relatively high molecular weight carboxylic acid, said carboxylic acid being unsaturated and being sulfurized by reaction with sodium pentasulfide.

2. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, suflicient to stabilize said oil against oxidation, of a metallic salt of a sulfurized relatively high molecular weight carboxylic acid, said carboxylic acid being unsaturated and being sulfurized by reaction with sodium pentasulfide.

3. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, sufiicient to stabilize said oil against oxidation, of an organo-metallic salt of a sulfurized relatively high molecular weight carboxylic acid, said carboxylic acid being unsaturated and being sulfurized by reaction with sodium pentasulfide.

4. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, sufficient to stabilize said oil against oxidation, of a salt of an organic base and a sulfurized relatively high molecular weight caboxylic acid, said carboxylic acid being unsaturated and being sulfurized by reaction with sodium pentasulfide.

5. A lubricant comprising in combination a. major proportion of oil of lubricating viscosity and a minor proportion, sufiicient to stabilize said oil against oxidation, of a salt of a sulfurized relatively high molecular weight aliphatic carboxylic acid, said aliphatic carboxy 'c acid being imsaturated and being sulfurized by reaction with sodium pentasulfide.

6. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, sufiicient to stabilize said oil against oxidation, of a metallic salt of a sulfurized relatively high molecular weight aliphatic carboxylic acid, said aliphatic carboxylic acid being unsaturated and being sulfurized by re action with sodium pentasulfide.

'7. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, sufficient to stabilize said oil against oxidation, of an organo-metallic salt of a sulfurized relatively high molecular weight aliphatic carboxylic acid, said aliphatic carboxamalgam i7 ylicaacid'beingzunsaturatedzandibeing:suliurized by reaction with sodium pentasulfide.

:lubricant -.comprising in -combination a mafior-iproportion 'JQf oil 401' alubrioating :wiscosity and anminor; picportionysufificientatostabilize said oi1 against oxidation; of a salt of anuorganic base and a sulfurizedarel'ativelyhighmolecular weight aliphatiwcarboxylic fiCid,'-::Sai'd aliphatic .carboxy-lic facid being unsaturated and being asulfurized by reaction-with sodium ,pentasuifide.

r9. ii-lubricant comprising in combination a major aproportion of :oil of .-lubr-icatingwviscosity and aminoriproportion, sufiicient to-stabilize said oilea-gainst oxidation, of-a:salt of -su1iurized -soybean: oil acids; said soybean oil acids :being sulfiuri-zed by: reaction @with sodium .wpentasulfide.

1 -10. .A lubricant comprisin in combination a major proportion of oil .offlluloricatin'g viscosity and a: minor proportion,l-sufficient-torstabilize said oilaagainst-oxidation, of 2 a salt. of sulfurized corn oil acids, said corn oil acids being sulfurized hy reaction withsodium pentasulfide.

11. 1A [lubricantcomprising in combination a major proportion-of oil :of lubricating viscosity and atminonproportion,r-suflicient m-stabilize. said oilUagainstoxidation, ofna salt of sulfur-ized oleic acid, said .oleic acid being ,sulfurizedrby :reaction withsodiumpentasulfide. I 'VI-ZRAQJubricant comprising incombination a major pmportioniof .oil .of lubricatin miscos-ity and atminorvproportion, suifioienti to ,stabilizevsaid 0311 against oxidation, 45f .ebenzyltrimethyl ammonium ,salts .of sulfurized corn oilhacids said corn oiliacids being sfilfurized by reaction .Withisodiumpentasulfi'de.

.213. A lubricant comprising inucombination a 8 major proportion: iofroilof lubricating viscosity F-a minor proportion, sufiicient to'stabilizesaid oil 1 against ioxidation, aof the'calcium :salt of asulfurize'd oleic acid, said oleicsacid being sulfur-med by reaction with sodium pentasulfide.

14. A lubricant comprising .in .combinationra major proportion of oil ..of lubricating viscosity and aminor proportion, sufficientitoostabilizasa-id oil against oxidation, .ofvtriphenyltin strumminfurized soybean oil acids, said w. soybean oiL acids being suifurized .by. r. reaction with sodium ;pentasulfide.

15. A lubricant comprising in combination a major proportion .of ,oil of lubricating .x'tiscosity and from 0.001 to 10 vper centof ra salt -ofaassulfurized relatively high molecular weighticarboxylic iacid said carboxyliciacid being unsaturated and being sulfurized 'by reaction :withnsodium pentasulfide.

BERT H. LINCOLN.

=GORDON 1D. BYRKIT.

l REFERENCESCITED The following references are pf'zrecordiin the file aof :this patent:

UNITED STATES PATENTS Number Name Bate 1,590,800 "Becker June 29,-1926 2,212,189 Brunstrum 'Augf20, 1940 2,237,096 'Dearborn Apr. 1, '1941 2,242,174 Burk May'13, 1941 2,246,282 'Zimmer 'June17','1941 2,341,453 'Lieber .Feb.-8, 1944 2,361,957 Musselman .'"1' T0v;""7, 1944