US2135092A - Built-up lubricating oil - Google Patents

Description

Patented Nov. 1, 1938 BUILT-UP LUBRICATING OIL GeorgeM. Maverick, Elizabeth, N. 1., assignor to Standard Oil Development Company, a corporation of Delaware No Drawing. Application December 20, 1933, Serial No. 703,213

9 Claims. (01. 87-9) The present invention relates to an improved 400-450 and it is preferably closely out. It lubricating oil, and especially to an oil for the should be well refined by any of the known methlubrication of internal combustion engines or ods and be free from carbon formin for similar service. The invention will be fully stances--asphalten'es, resins and the like. Such understood from the following description of the an oil is preferably purified to such a degree by lubricant and its method of production. acid treatment, hydrogenation, solvent extrac- Lubricating oils for use in internal combustion tion or the like that it is characterized by a highengines are subjected to extremely severe service er rate of oxidation than the crude cut from and it has been fortunate that the naturally ocwhich it is derived. The so-called white. min- 10 curring oils have accidentally been endowed with eral oils can be used for this purpose as well as 10 properties suitable for such'service, if only in an synthetic lubricating oils prepared by condensaimperfect degree. Recent studies of the several tion of cracked oils or waxes, or other active attributes desired for lubricating internal comderivatives such .as halides. It has also been bustion engines have made it evident that several found that the lighter fractions of lubricating 5 separate properties are desired for accomplishoils prepared by destructive hydrogenation at l? ing difierent purposes and are so diverse as not relatively low temperatures, say from '700-800 to he possessed to any marked degree by any F., whereby they are substantially completely satsingle class of substances. If a lubricant is urated, are also excellent for the present purpose. chosen for its superior qualities in one respect, The vehicle may be a waxy oil or a dewaxed oil 0 it has been found to be proportionately lacking or derived from wax free crudes. If a waxy oil in some other respect which is equally desirable. is used, a pour inhibitor may be added.

Even at present the best lubricating oils hold To the vehicle described above is then added their place by a compromise; in other words, hya thickening agent and for this purpose natural, drocarbon lubricating oils have none of the demodified natural, or Sy t linear hydrocarsired attributes to a very high degree and are bon polymers are the most'd'esirable; for ex- 25 suitable only because they show all of the desired ample, polymerization products of alpha oleattributes albeit, to a rather low degree. fines, particularly of isobutylene are highly de- In the present invention the problem of lubrisirable. These materials are polymerized by the {Eating automotive gines is attacked from an action of active clay, carbon, or the well-known entirely df e Point Of e y Se ecti nd halide catalysts especially aluminum chloride and 30 mixing several different ingredients, each selected boron fluoride. Other materials may also be to serve a particular purpose, so that 'it has been used, such as polymerized indene, styrene or the possible to produce oils in this manner which are like or their alkylated or hydrogenated polymermarkedly superior to natural or modified natural ized products, as well as condensation products pounding the individual ingredients for the sevatoms with single ringed aromatic hydrocarbons, eral difierent purposes, the various properties denamely, ethylene dichloride with benzol. Natsired can be obtained to an extremely high deural materials such as rubber are also suitable gree and that while no single ingredient possesses but hydrogenated products are much more de- 40 all of the characteristics desired, the different sirable. The hydrogenated products of related constituents are so chosen and mixed in such materials such as the balatas, guttas, and guayule proportions as to supply the desired properties may also be used. The amount of thickener to be with any particular emphasis desired and to used depends on its molecular weight and the greatly minimize undesirable properties. viscosity of the product desired. If a high 5 The present oils are prepared by first selecting molecular weight polymer is selected, less is rea suitable vehicle or base, the primary purpose of quired to produce a given thickening effect than which is to carry the several substances added in ii a lower polymer is employed. In general, howa fluid form capable of easy flow through the enever, the amount varies between, say, 140% by gine. This vehicle is preferably a highly purified weight of the vehicle. These thickeners increase hydrocarbon oil of low to medium viscosity, that the viscosity well above 50 seconds Saybolt at 50 is to say, generally lower than the viscosity now 210 F.; for example, 60, 75, or over 100 secused for lubricating automotive engines. For ends at 210 F. as desired. In this way, irrespecexample, it may be free from 40-50 seconds Saytive of the particular vehicle, it is possible to bolt at 210 F. The oil is sufllciently high boilproduce all of the grades of motor lubricants by ing to give it a suitable flash point of, .say, varying the amount of the polymer added. 55

lubricants. It has been found that by comof dihalo hydrocarbons of less than five carbon 35 These thickening agents not only have the property of increasing viscosity but also the desirable property of decreasing the slope of the viscositytemperature curve, or in other words of increasing the viscosity index of the blend.

The second essential substance to be added to the base stock is an oxidation inhibitor. These substances are well kriown and any reasonably good inhibitor will serve the present purpose; for example, phenolic or preferably c-resolic substancesthe mono-, di-, and hydroxy benzols or cresols. The naphtholsalpha and beta-or the naphthylamines may also be used. Sulfur compounds are useful, for example, aromatic disulfides, mercaptans or polysulfides, whether aromatic or aliphatic, and especially the trisulfldes' which are non-corrosive. These substances are merely mentioned as examples to indicate the class or nature of the materials to be used for the present purpose. The amount used varies with the potency of the particular inhibitor but in general they may be used in amounts from .0l-.05 to .1% or even up to 1% or more.

The third essential ingredient is a substance from-the class of the sludge dispersers. The action of these materials is obscure but they appear to maintain oxidation products of the oil in a state of suspension, checking to a marked extent the polymerization or agglomeration and precipitation on the hot portions of the engine, especially the valves, rings, pistons and in the crankcase. The substances themselves, whatever their action may be, comprise the class of synthetic hydrocarbons of high boiling point,.so high in fact that they are to be classed as substantially undistillable. They are in addition rich in hydrogen, the carbon-hydrogen ratio closely approaching that characteristic of the paraffin series of hydrocarbons. They must also be free flowing liquids. Substances of the type mentioned above may be prepared synthetically: by condensing hydrocarbon waxes or paraflin oils, which are themselves as close as possible to being completely saturated. The high molecular weight initial materials are more desirable than the lower, for example, a condensation product of petrolatum is ordinarily to be preferred to a condensation product of a low molecular weight wax. Condensation may be accomplished in any convenient manner, for example, by subjecting the oil or wax to high voltage, high frequency alternating electric discharges or by more strictly chemical means, for example, by chlorinating and subsequently condensing the chlorinated hydrocarbons during which reaction hydrochloric acid is removed. Condensation should not proceed so far asto produce rubbery insoluble substances but readily soluble or dispersible materials. This can readily be accomplished by adjusting the time of reaction. Olefines derived from waxy hydrocarbons may also be condensed, preferably using aluminum chloride or very similar conden-- sation catalysts. Cracked waxes or cracked paraifin oils furnish a good source of condensable materials which yield substantially saturated polymers. If desired, a relatively small amount of an aromatic hydrocarbon may be added during condensation, for example, 5-10%, in order to furnish condensation nuclei, although it should be understood that this is not required and even where used the products still closely approach the carbon-hydrogen ratio of saturated hydrocarbons. r

The amount of the sludge dispersing substances varies with their particular potency. Ordinarily 1% is sufficient, but this amount may be increased to 2% or 3% where less active substances are used. There is a definite optimum quantity which if exceeded shows less dispersing power. The preferred amount is sosmall as to show no very substantial increase in the viscosity of the blend as measured at 210 F. For example, the increase in viscosity due to the sludge dispersing agent is generally not more than 2-4 seconds Saybolt at 210 F.

While the hydrocarbon materials listed above are preferred, it is possible to use oxygen-containing substances, for example, polymers of high boiling acids; ethers, ketones, esters and the like or fatty substances, prepared by the action of high frequency, high voltage, electric discharges or other known means. Ordinarily these are used in larger amounts than the best hydrocarbon dispersing agents.

In order to produce a lubricant with a high degree of oiliness, friction reducing agents may be added. These may be selected from the various types now known-fatty oils, fatty acids, or higher alcohols may be used-but it is preferred to use highly purified esters, particularly those synthetically prepared, so as to avoid the presence of non-fats, unstable gummy materials and the like whch are always contained to a more or less substantial degree in natural esters either animal'or vegetable. Esters boiling above or 200 C. are preferred, since they will not be lost from the hot oil and may be prepared from naturally occurring acids such as stearic or oleic or from acids obtained by the oxidation of paraffin wax, particularly at low temperatures, with air. The methyl, ethyl, and propyl esters of these acids are very satisfactory and are to be preferred to the higher alkyl esters. The amount of the ester is ordinarily from .5 to 5%. The presence of these friction reducing agents greatlyincreases the load bearing capacity of the oil and reduces the friction in the bearings.

. Other agents besides the esters mentioned above may be used to increase bearing pressures and to reduce friction; for example, sulfurized bases, chlorin-containing organic' materials in relatively small amounts, or substances containing both chlorin and sulfur in the same molecule, or if desired in separate substances. Soaps of the alkali or alkaline earth or heavy metals such as lead and zinc, may be used in small amounts.

Material of the type of carbon preventers may be added, if desired. These materials are distinguished from the sludge dispersers, in that they show little or no effect on Sligh numbers, and are, perhaps, misnamed in that they probably do not actually decrease the amount of carbon formed. Their action is rather to influence the type of carbon rendering it soft and fluffy rather than fiinty and adherent.

The amount of carbon retained within the engine is influenced by these so-called preventers. High boiling soluble esters such as butyl, amyl, hexyl phthalates, benzoates, salicylates or amines of the same general boiling range are used. These may be used in amounts up to 1% or 2% but generally not over about 5 to 10%.

In addition to the ingredients mentioned above,

other various materials may be added such as pour inhibitors if a waxy vehicle is originally employed or if waxy materials are added for any reason. The preferred pour inhibitors are hydrocarbons produced by low temperature aluminum chloride or high frequency electrical con- As a vehicle a highly refined mineral oil of the following inspection is selected:

Gravity degrees A. P. I 28.7 Viscosity at 100 F seconds Saybolt 265 Viscosity at 210 F do 50 Flash 410 Pour point ..degrees Fahrenheit--.

Sligh test (2% hr.) 10.5

To 100 parts by weight of the vehicle is added two parts of a substance prepared by the polymerization of isobutylene at 20 F. with boron fluoride. To parts of anisopropyl ester of acids produced by the air oxidation of paraflln wax is also added together with one part of a condensation product of petrolatum (chlorinated to about" 12%) with 10% of naphthalene and as an oxidation inhibitor .05% of alpha naphthol. The fin ished composition is an excellent medium grade motor lubricant extremely resistant to with a very low tendency to sludge and iness. It is excellently adapted to the in of new or green motors.

In a second composition a similar vehicle is used which has been prepared by destructive hydrogenation of heavier oils at a temperature of 700-800 F. and under pressures of 200 atmospheres whereby the oil is substantially completely saturated. To 100 parts of the oil vehicle is added 3 parts of hydrogenated rubber together with 2% parts of ethyl oleate, which serves as an antifriction agent. One part of a condensation product of petrolatum produced by the action of high frequency alternating electric discharges is added as a dispersing agent and as the oxidation inhibitor .1% of naphthyl disulfide is employed.

III

To an oil vehicle similar to that used in Example II are added the same thickening polymer together with a .05% of alpha thio naphthol as an oxidation inhibitor and a sludge disperser oi the type and in the amount used in Example I.

To the all last described is added a small quantity, about 2%, of a substance prepared by chlorinating paramn wax and reacting the same with sodium polysulflde so as to obtain a final product containing sulfur but free from chlorin which gives the oil extreme pressure bearing properties.

In the above compositions the nature and the oxidation high oilbreaking viscosity of '70 seconds amount of the various ingredients may vary to suit particular conditions to be met and it is possible to make'a full and complete line of motor oils or oils for other, similar purposes by adjusting the composition of the blends as brought out in the previous examples.

My invention is not to be limited to the use of particular compositions shown, nor to any particular ingredient-but only to the following claims in which it is desired to claim all novelty inherent in the invention.

I claim: y

1. An improved lubricant, comprising a vehicle which is a high boiling hydrocarbon oil of viscosity lower than that ordinarily usedior lubricating purposes, a thickening polymer of the linear hydrocarbon type, an oxidationinhibitor and a sludge disperser;

2. An improved lubricant, comprising a hydrocarbon oil vehicle of viscosity below the lubricating range, a thickening polymer selected from the group comprising polymerizedv isobutylene, hydrogenated rubber, and the condensation products of di-halo hydrocarbons of less than five carbon atoms condensed with mono-cyclic aromatic hydrocarbons, an oxidation inhibitor and a sludge disperser.

3. An improved motor lubricant, comprising a high boiling hydrocarbon vehicle of less viscosity than used for lubricating purposes, a thickening polymer and a dispersing agent comprising a high boiling synthetic hydrocarbon condensation product, free flowing and having a carbon-hydrogen ratio closely approaching that of the paramn series, and an oxidation inhibitor.

4. An oil according to claim 3 in which the thickening polymer is produced from isobutylene.

5. An oil according to claim 3 in which the sludge disperser is obtained by condensation of waxy hydrocarbons and is used in the proportion of about 1%.

6. An oil according to claim 3 in which the sludge disperser is obtained by the condensation of waxy hydrocarbons on an aromatic nucleus and is used in the proportion of about 1%.

7. Oil according to claim 3 in which a small amount of an organic ester boiling about 150 C. I

is added.

8. A lubricant of suitable viscosity for thelu brication of motors, having a high resistance to oxidation and concomitantly a low tendency to deposit sludge, comprising a hydrocarbon oil vehicle, oi lower viscosity, a suiiicient amount 01 a thickening agent of the polymer type to bring the viscosity of the vehicle to that desired in the motor 011, an effective amount of an oxidation inhibitor and an eflective amount of an agent capable of maintaining sludge in suspension.

9. A lubricant oi suitable viscosity for the lubrication of motors, having a high resistance to oxidation and concomitantly a low tendency to deposit sludge, comprising a high boiling hydrocarbon oil obtained by purification of crude oil and having a viscosity lower than that desired in the finished lubricant, a sumcient amount of a thickening polymer of the linear hydrocarbon type to bring the viscosity of the hydrocarbon oil to that desired in the finished lubricant, an eflectlve amount of an oxidation inhibitor and an efl'ective amount of an agent capable of maintalning sludge in suspension in said oil.-