US2129281A - Lubricating oils - Google Patents

Description

Patented Sept. 6, 1938 LUBRICATING OILS Bert H. Lincoln and Gordon D. Byrkit, Ponca City, Okla., assignors to Continental Oil Company, Ponca City, Okla., a corporation of Delaware No Drawing. Application March 23, 1936, Serial No. 70,405

15 Claims.

Our invention relates to lubricating oils and specifically comprises such products as new compositions of matter. l

Present day mechanical devices require lubrieating oils of high film strength and of high oiliness characteristics. It has been found that the present day hydrocarbon lubricants of the very highest quality are deficient in these two very important characteristics. These two properties are of vital importance under conditions of thin film lubrication where the lubricant has been squeezed from between the friction surfaces due to high pressures, slow speeds, and other causes. It is readily seen that the viscosity or the body of the lubricant plays no part in this type of lubrication and that the remaining film of oil should tend to keep the coefficient of friction as low as possible and must have a very high film strength and be of high oiliness value to prevent rupture of the film of the lubricant, which would cause seizure.

Mechanical devices are being designed for higher pressure operation, and the film strength of the best quality straight hydrocarbon lubricants has been found to be too low and not-sulficient; therefore an invention which provides the means of improving the film strength of these lubricants is of great importance to the art of lubricant manufacture and to the designer and fabricator of mechanical devices.

Substantially all machines operate in part or at times totally under conditions of boundary or thin film lubrication, under which conditions the oiliness or unctuosity of the lubricant is the first and primary requisite of efficient operation.

Those skilled in the art of lubricant manufacture or machine manufacture will readily appreciate the value of an invention that will improve the oiliness of these otherwise high quality lubricants.

Under some circumstances a very small amount of an addition agent will stabilige a hydrocarbon oil against formation of corrosive oxidation compounds or sludge forming compounds and as little as 0.001 percent is often sufficient.

;) In starting idle mechanical equipment which is lubricated from a sump by pumping or circulating the lubricant, there is always a short period of, time during which the rubbing surfaces must operate under conditions of dry friction if ordi- 50 nary hydrocarbon lubricants are used. With dry friction, the wear on friction surfaces is extreme; and during cold weather when the lubricant is sluggish, or during periods when the lubricating system is not functioning properly for one reason 55 or another, rubbing surfaces may not only suffer considerable wear, but may be damaged to the point where they must be replaced. The-product of our invention has the very important property of reacting with the metal surfaces, penetrating or adsorbing on the metal, and. leaving a film of 5 lubricant with high oiliness character which remains on the metal surface irrespective of the length of time the machine is idle.

This high oiliness film is very even and results in smooth operation which may be easily dis- 1o cerned by the experienced operator and lubricating engineer.

When the hydrocarbon lubricants are diluted with unburned fuel or with other light hydrocarbons, the small degree of oiliness of the original 15 hydrocarbon lubricant is greatly decreased. We have found that the addition of the product of our invention to hydrocarbon lubricants more than compensates for the loss in oiliness and loadcarrying ability by dilution. 20

One object of our invention is to provide a lubricating composition having improved film strength and extreme pressure characteristics.

Other and further objects of our invention will appear from the following description: 25

We have found that certain compounds are adsorbed or absorbed by metals forming a plurality of layers or films on the surface of the metal, which films are very tenacious (they have a high film strength) and have the property of reducing the coefficient of friction to a greater extent than any known lubricant. The com pounds which most readily are adsorbed by metals are ones consisting of polar molecules, that is, molecules of unsymmetrical electrical character which contain an atom or group of atoms exhibiting a secondary or residual valence. These polar compounds tend to produce regimentation of the molecules of hydrocarbon oil when added thereto. If a metal is immersed in a strongly polar compound, a regimentation or cybotaxis of the molecules will take place in the adsorbed film, the molecules being oriented with respect to the surface of the metal by which they are adsorbed. The films of polar compounds, adsorbed by a metal, can be plainly seen and the orientation of the polar molecules on the metal surface ascertained by X-ray diffraction methods, in which a monochromatic X-ray beam is passed through the adsorbed films at an angle. The series of films acts as a diffraction grating and a diffracted beam will be reflected from the planes of the films and can be recorded photographically. The X-ray photographs will clearly show the orientation of the molecules by characteristic pictures.

X-ray investigation has shown that strongly polar molecules form adsorbed films of unusual thickness and regularity of arrangement. Thicknesses of films of 9,000 Angstrom units have been obtained, which are of enormous magnitude when compared to molecular dimensions.

In general, our invention comprises the addition of relatively small amounts, suitably from 0.001 to 10 percent, of organic silicon compounds to hydrocarbon lubricants. For some purposes, we use from 0.1 to 2 percent of the organic silicon compound in the hydrocarbon oil. For other purposes we use from 0.001 to 0.1 percent of the silicon compound in the lubricant. The hydrocarbon portion of our compound may be comparatively viscous or non-viscous, refined or unrefined, natural or synthetic. In other words, any hydrocarbon oil may be used within the scope of our invention.

In practicing our invention, we use certain organic silicon compounds which may contain other inorganic elements, such as halogen, oxygen, hydrogen, sulphur, phosphorus, et cetera. The organic silicon compounds which are particularly suited to our purpose are of eight types:

R4Si, in which the R's are organic radicals, at least one of which contains four or more carbon atoms. An example of this type is tetralauryl silicane.

RsSiX, in which the Rs are organic radicals, at least one of which contains four or more carbon atoms, and X is hydrogen or a halogen. Examples of this type are trioctadecyl silicane and trialuryl silicon chloride.

RzSiXz, in which the R's are organic radicals, at least one of which contains four or more carbon atoms, and X is hydrogen or halogen. An example of this type is di-octyl silicon dichloride.

RSiXs, in which the R is an organic radical containing four or more carbon atoms, and X is hydrogen or halogen. An example of this type is p-tolyl silicon trichloride.

RsSiOR, in which the Rs are organic radicals, at least one of which contains fouror more carbon atoms. An example of this type is triethylsilicon lauryl ether.

R2Si(OR')2, in which the Rs are organic radicals, at least one of which contains four or more carbon atoms. An example of this type is diethyl silicon dibutyl ether.

RSi(OR')3, in which the R's are organic radicals, at least one of which contains four or more carbon atoms. An example of this type is octadecyl triethoxy silicon.

RSi0.0R, in which the Rs are organic radicals, at least one of which contains four or more carbon atoms. An example of this type is amyl alpha-siliconaphthoate.

In practicing our invention, oil-soluble silicon compounds are to be selected. Such compounds as are insoluble in hydrocarbon oil may be used in colloidal suspension or emulsion in the hydrocarbon oil, accompanied by suitable stabilizing agents for rendering the emulsion or suspension permanent. The selection of a particular compound or combination of compounds to be used as an addition agent to hydrocarbon oil isto be made considering the use to which the blend is put. Thus, if water is likely to be present during use, a stable silicon compound or combination of compounds is selected which are not affected by water. If a particular added silicon compound proves too volatile for its application, a higher boiling silicon compound should be used and the more volatile compound used for blending in a hydrocarbon oil intended for duty at lower temperatures. Thus, normally, very volatile silicon compounds, for example, tetramethyl silicon, are suitable for blending in hydrocarbon oils for lubricating refrigerating machines. In general, we prefer to use compounds having boiling points over 150 F. Such details of practice will be apparent to anyone skilled in the art.

It is sometimes advantageous to combine more than one of these compounds in a blend to obtain particular properties. We accomplish this by mixing two or more of these compounds together and blending the mixture with hydrocarbon oil, or by blending one in the hydrocarbon oil, blending the second into this mixture, and so on until the composition is complete.

We have found that the silicon compounds above set forth may be more effective in some compositions if a comparatively small amount of halogen-free, oxygen-containing carbon compound is included in the composition. The oxygen-containing carbon compound may be of aliphatic, aromatic, or hetero-cyclic nature and may be blended with the organic silicon compound in amounts ranging from 5 to 50 percent.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. is within the scope of our claims. It is further obvious 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.

Having thus described our invention, what we claim is: I

1. A lubricant comprising in combination a major proportion of a hydrocarbon oil and a minor proportion of an organic silicon compound having at least one carbon-silicon bond.

2. A lubricant comprising in combination a major proportion of a hydrocarbon oil and from .1 of one percent to 10 percent by weight of an organic silicon compound having at least one carbon-silicon bond.

3. A lubricant comprising in combination a major proportion of a hydrocarbon oil and a minor proportion of an organic silicon compound having at least one carbon-silicon bond and the formula in which R. represents an organic radical and R represents an organic radical containing four or more carbon atoms.

4. A lubricant comprising in combination a major proportion of a hydrocarbon oil and a minor proportion of an organic silicon compound having at least one carbon-silicon bond and the formula in which R represents an organic radical, R represents an organic radical having four or more carbon atoms, and X represents hydrogen or a halogen.

5. A lubricant comprising in combination a major proportion of a hydrocarbon oil and a This is contemplated by and.

aiaaaer minor proportion of an organic silicon compound having at least one carbon-silicon bond and the formula R! XS:iX x

in which R represents an organic radical having four or more carbon atoms, and X represents hydrogen or a halogen.

6. A lubricant comprising in combination a major proportion of a hydrocarbon oil and a minor proportion of an organic silicon compound having at least one carbon-silicon bond and the formula R il-R 4m in which R represents an organic radical and. R

in which- R. represents an organic radical and R. represents an organic radical containing four or more carbon atoms.

8. A lubricant comprising in combination a major proportion of a hydrocarbon oil and a minor proportion of an organic silicon compound having at least one carbon-silicon bond and the formula RI on-si-on in which R represents an organic radical aiid R represents an organicradical containing four or more carbon atoms.

9. A lubricant comprising in combination a major proportion of a hydrocarbon oil and from 0.001 of one percent to 0.1 percent by weight of an organic silicon compound having at least one carbon-silicon bond.

10. A lubricant comprising in combination a major proportion of a hydrocarbon oil and a minor proportion of an organic silicon compound having at least one carbon-silicon bond and the formula R R-i-R in which R represents an organic radical and R represents an organic radical containing four or more carbon atoms. 7

11. A lubricant comprising in combination a major proportion of a hydrocarbon oil and a minor proportion of an organic silicon compoundhaving at least one carbon-silicon bond and the formula RSiOR 6B in which R represents an organic radical and R represents an organic radical containing four or more carbon atoms,

12. A lubricant comprising in combination a major proportion of a hydrocarbon oil and a minor proportion of an organic silicon compound having at least one carbon-silicon bond and the formula 1R no-si-on R in which R represents an organic radical and R represents an organic radical containing four or more carbon atoms.

13. A lubricating oil comprising in combination a major proportion of a hydrocarbon oil and a minor proportion of tetralauryl silicane.

14. A lubricating oil comprising in combination a major proportion of a hydrocarbon oil and a minor proportion of trilauryl silicon chloride.

15. A lubricating oil comprising in combination a major proportion of a hydrocarbon oil and a minor proportion of para-tolyl silicon trichloride.

BERT H. LINCOLN. GORDON D. BYRKIT.