US3208940A

US3208940A - Lubricating compositions and methods of lubricating

Info

Publication number: US3208940A
Application number: US180883A
Authority: US
Inventors: Robert S Owens; Pierre Leon E St
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1961-04-10
Filing date: 1962-03-19
Publication date: 1965-09-28
Anticipated expiration: 1982-09-28
Also published as: GB988063A; DE1246920B

Description

v Sept. 28, 1965 R. s. OWENS ETAL 3,208,940

LUBRICATING COMPOSITIONS AND METHODS OF LUBRICATING Filed March 19, 1962 'lnvenfors Robert S, Owens,- Leon 5 5/. Pierre,

5y W and 7' heir Afforn e y- Preferably, R" does not exceed 30 carbon at "ms, although It will of course be longerchain radicals may be used. understood that mixtures of these olefins may be employed in the practice of our invention. I The ester. component in this particular'class of lubri- -can ts,/which must be free of 'olefinic unsaturation, comprises a compound having the formula 1 (II) Q x z Z is a monovalent, linear, straight chain saturated aliphatic radical selected from theclass consisting of linear alkyl and linear fluoroalkyl radicals of from 11 to as' long as-4O carbon atoms or more, -X is a divalent radical se- O O I carbonyloxy (.O- (and the mirror-imaged J-radical) sultoxy (S), and sulfonyl (-8-), X and Z together represent the monovalent group .XZ whicn encompasses the radicals OZ, SZ

whereZ is as previously defined. Qis a monovalent lower alkyl straight chain radical of from l'to 3 carbon In general, amounts of the olefin as low as in the mixture give significant results. We have found that the olefin component advantageously is present in an amount equal to about 595%, by weight, of the total Weight of the olefinand the other component: represented by Formula II. Obviously, mixtures of the olefins may be used in combination with mixtures of the compounds represented by Formula II.

Because-of the ease of preparatiom'ready availability of raw materials for synthesis and their suitability and outstanding properties as lubricants and as additives to other well known lubricants, we prefer to use as the olefiniccomponent one which is a straight chain unsaturated aliphatic hydrocarbon having olefinic unsaturation' example, mineral oils of lubricating viscosity, greases vmade from such lubricating oils, silicone lubricating oils,

atoms selectedfrom the class consisting of alkyl radicals and fiuoroalkyl radicals, e.g., methyl,- ethyl, propyl, fluoromethyl, difluoromethyl, trifluoromethyl, 1,2- difluoroethyl, perfluoropropyl, etc. v

' Included among the normal compounds (as contrasted to branched chain compounds) represented'b'y Formula I are, for instance, decene l, dodecene-l,- tetradecene-l,

dodecene-Z, tetradecene-Z, pentadecen'e-l, hexadecene-l (cetene), octadecene-l', octadecene-2, 1-fiuor0tetradecene-l, 1,2-difluorotetradecene-l, l-fiuorohexadecene-l, trifluorohexadecene-l, 1,1,2,2 tetrafluorohexadecene-Z, etc., as well as mixtures of such olefins.

Among the radicals which Z may be are, re".- example,

undecyl, dodecyl, tetradecyl, hexadecyl, 'pentadecyl, eicosyl, docosyl, tricosyl, triacontyl, tetracontyl, 1',1,l,2,2,- penctafiuorotetradecyl, tetrafluorododecyl hexafluorotetradecyl, etc.

Examples of compounds coming within the scope of. Formula II are, for instance, methyl laurate, propyl laurate, methyl myristate, methyl palmitate, methylcarbonate, 'methyl tetradecyl sulfoxide, ethyl *hexadecyl sulfone, ethyl tetradecyl ether, ethyl eicosyl sulfide, methyl monofiuorononadecyl carbonate, fluoromethyl dodecyl ether, methyl tetrafluorotricosyl sulfone, methyl hexafiuorotriacontyl sulfoxide,- propyl trifluoroundecyl ketone,

ethyl trifluorostearate, 2-fiuoroethyl octadecyl sulfide, l,2-difluoropropyl eicosyl ketone, fiuoroethyl tetrafiuorotricosyl sulfone, methyl trifiuorotricosyl ether, etc- The proportions of the two ingredients can be varied widely and generally are. preferred in such proportions that the combination of the'two imparts the desired lubrieating characteristics and represents afiuid mixture which has a solidification temperature well below room tem perature, for example, below 15 0., thus makingthe lubricant useful over abroad spectrum of temperatures.

.one' part to the other.

diester lubricating oils, polyester lubricating oils, silicate ester lubricating oils, etc. Aqueous emulsions of our lubricating composition, either alone or in combination, with other well known: cutting oils can beused toadvantage in cutting and grinding applications. Our lubricants are particularly useful in lubricating solid surfaces which move relative to each other. where one of the surfaces is aluminum. When one solid surface moves relative to another surface with a lubricant between the two surfaces, there maybe a completefilm of lubricant separating the two surfaces or there may be varying degrees of contact between the surfzicesJThe former condition exists under ideal hydrodynamic lubrication, while the latter condition is characteristic of boundary lubrication. Complete hydrodynamic lubrication may be obtained under certain ideal conditions found in bearings but is influenced by suchfactors as design of the two solid surfaces, load on the surfaces, and the relative speed of However, even under these conditions, boundary lubricatingproblems are encountered during stopping and starting, operations, and from a practica-lstandpoint, perfect hydrodynamic lubrication i is approached rather than attained. Therefore, the ability of our lubricants to improve the boundary lubrication of solid surfaces moving relative to each other where one of the surfaces is aluminum, is a feature which has been greatly desired in the past.

In addition to our lubricants improving the lubricating characteristics of two solid surfaces where both surfaces are aluminum, it should also be understood thatou'r lubricants are also useful in those cases where one of the surfaces is aluminum and the other surface is another solid material, as, for instance, various metals, for example, iron, molybdenum, copper, tungsten, magnesium, zirconium,'chromium, nickel. etc., alloys of said metals, such as steels, brasses, the alloys of magnesium, cobalt, zirconium, beryllium, aluminum,.iron, zinc, etc. In addition, the other surface may be still other solid materials, for example, wood, molded synthetic resins, laminates, etc., or special compounded compositions such as'porous metal, graphite, graphite impregnated metal, soft bearing alloy-s, e.g., babbitts, etc., or very hard compositions, for example, metal carbides, nitrides, etc. The lubrication of the above metals alone other than aluminum, by means of our compositions is not precluded. Thus, the lubrication of surfaces where one of the surfaces is titanium, beryllium, tungsten, etc., useful for fabricating structural shapes is'included in the scope of the invention.

Nominally, in the design of equipmeritiwhcre one solid surface moves relative to another, both solid surfaces 'fide, tin sulfide, graphite, etc.,

be incorporated to produce a gel structure. Particularly are the same material if the wear is to be equal on both parts or one is made of a material softer than the other when the wear is to be essentially all on the softer part.

' This is usually done when one part is easier to replace than the other or the one part is being cut or shaped by the other.

the boundary lubricating properties of the latter. Generally, wehave found that for a solid surface of aluminum where the other surface moving relative to the first is on of even small amounts, and, for exalso aluminum, the coefficient of friction is generally greatly improved where at least 50%, by weight, of the total lubricant constitutes the mixture of the olefinic material and the compound represented by Formula 11 above. On a weight basis we may use from l0 to 90 parts of our lubricant mixture per 100 parts of the other usual lubricant. For the first time, this discovery permits the use of a wide variety of aluminum compositions in the fabrication of bearings and like surfaces, since, as far" as we are aware, prior to our invention, no way was satisfactorily known to preventgal-ling and seizing of bearings made of aluminum. Although specific alloys of aluminum were made for bearings, the useof such compositlons required concessions to be made as to the bearmg clearances, life, etc., in order to provide adequate performance.

Likewise, our lubricating compositions permit aluminum materials to be shaped, for example, by drawing, spinning, extrusion and the like,.with a very smooth finish. When our materials are used as the lubricant withoutdilution, the aluminum composition can beformed with a smooth, mirror-like finish whichiisdifiicult to obtain by the use of previously known lubricants. Typical examples of the various aluminum compositions (including aluminumfalloys) that can be lubricated by our lubricants are those alkaline earth soaps of the fatty acids, but other soaps mayalso be used, for example, zinc, tin, lead, copper, etc., soaps of the fatty acids. A particularly desirable grease composition may be made from lithium stearate or lithium hydroxy stearate. These grease compositions may be made by any of the well known methods, for example, as disclosed in US. Patents 2,450,22l-Ashburn et al.;'2,450,- 222-Ashburn et al.; and 2,260,625Kistler.

It will of course be apparent to those skilled in the art that in addition, pour depressants, stabilizers, inhibitors, particularly oxidation inhibitors, and the like, may be added to our lubricating compositions to impart to the latter the additional properties which these particular additives are designed for.

In order that those skilled in the art may better understand how the present invention may be practiced, the following examplesare given by way of illustration and not by way of limitation. In all of the examples, the percentages are by weight.

The apparatus used to test our lubricants shown in the following examples under boundary lubricating conditions is described in the attached drawing, in figure shows partly in section the portion of a standard four-ball wear tester which has been modified to evaluate lubricating compositions using metals in various shapes other than the balls.

This .apparatus comprised a modified four-ball wear and their holder with a cup and washer, as shown in the disclosed on pages 851-853 and 865-958 of Metals Handbook,vol. l, Propetities and Selection of Metals, American Society for Metals, Novelty, Ohio, Eighth Edition (1961), for example, the high purity aluminum alloys which are figure. Rider 1, made of aluminum (or another metal), is cup-shaped and is rotated at preselected speeds against stationary test washer 2 made also of aluminum (or another metal) by means of a motor driven shaft 3 to which rider 1 is attached by machine bolts 4 and 4'. Washer Z is rigidly fastened'to the base 5 of chamber 6 by means of machine bolt 7 through the medium of a rubber member designed to insure proper alignment between washer 2 greater than 99% aluminum, e.g., EC alloy, 1060 alloy,

1100 alloy, etc., alloys of aluminum with other metals, for example, copper, silicon, tin, zinc, etc., asare more fully described on pages 955-958 of the above reference. Typical of the mineral, or hydrocarbon oils of lubricating viscosity are the hydrocarbon lubricants obtained from petroleum. These products normally have viscosities in the range of 25 to 10,000 Saybolt Universal Seconds (S.U.S.), and may be a single-mixture of hydrocarbons. Typical of the-silicone lubricating oils are those disclosed in, for example, US. Patents 2,4l0,346--Hyde; 2,456,- 496- -Ford et al.; 2,469,888-Patnode; 2,469,-890-Patnode; 2,970,162-Brown; etc.

Typical of the diester, polyester, and silicate ester lubricants are those disclosed in US. Patents 2,450, 22 l--Ashburn et al.; 2,450,222-Ashburn et al.; US. Patent 2,977,- 301-Bergen et al.; and on pages 16-24 of Technical Pub lication No. 77, published by American Society for Test ing Materials, Philadelphia, entitled, Symposium on Synthetic Lubricants. Other lubricating materials, as well as suitable mixtures of these lubricating materials, may

be used in the practice of our invention without departand rider 1. A reservoir of lubricant 8 under test is maintained around the test pieces. Chamber 6 rides on a series of ball bearings, one of which is shown as 9, which ride upon member 10, which forms the uppermost portion of plunger 11, which is connected to a hydraulic system (not shown) to permit. various loadings to be established between the two test samples 1 and- 2. When rider 1 is rotated against test washer 2 by means of clockwise rotation of shaft 3, chamber 6 will rotate upon member 10 I due to the frictional force existing between members 1 and 2. The force required to prevent such rotation is 0' measured by a strain gauge attached to arm 12. This modification permits the coefiicient of friction to be calculated and examination of riders 1 and 2 permits evaluation of the amount and type of wear produced.

Using this apparatus, the following measurements were made in the following tests when the rider having a fiat annular surface area of 0.393 square inch was rotated at 0.88 rpm. to give a surface speed of 0.0461 inch per second against the test washer under of a load of 10 kg. These conditions represent operation in the boundary friction region and represent the most difiicult condition of bearing operation from a lubricant standpoint. All percentages are by weight and the tests were run at room temperature (about 22 C.) for one hour unless otherwise specified. In some of the examples below the rider and washer were of materials other than aluminum specifically stainless steel and titanium in order to show the versatility of our lubricants.

EXAMPLE 1 In this example, a lubricant mixture consisting of cetene and 30% methyl stearate was introduced in the above-described apparatus in which the rider and washer which the single 7 were both 403 stainless steel (115 43% chromium). The test for the ClllClUlltfy of the lubricant was conducted for 1.5 hours at the end of which time it was found that the cocilicient offriction remained sleudy at around 0.16. Examination of the wearsurl'acc of the washer showed ic-discernible wear with the exception thatitwas highly polished. For comparison, when cetene alone was tested under the same conditions using the same stainless steel washer and rider the coefficient of friction was quite erratic and showed a wide scatter between 0.27 and 0.4.- In addition, the surface of the washer showed dcepgroov -ing indicating excessive wear.

EXAMPLE 2 the lubricant mixture in the above-identified apparatus in which the rider and washer were both alumihum.- Additionally, cetene alone (methyl stearate a sol-{d at room.

temperature) and cetane alone, were also-tested for comparison purposes to show the unexpected advantages of tions as lubricants in the above described test apparatus,

mixtures of 'cetene with either n-butyl stearate or isopropyl stearate ,were also evaluated. Finally, a vegetable oil (corn oil) was tested to show the effect of having poly-. unsaturation in one ester molecule. This vegetable oil consisted essentially of glycerides of fatty acids containing, on a weight basis, acid residues of the following acids; 34' to 62% linoleic acid, 19 to 49% oleic acid, 0.2 to 1.6% hexadecenoic acid, 8 to 12% palmitic acid, and less than 5% of small amounts of myristic and stearic acids. The 150 SUS hydrocarbon-oil was a mineral lubricating oil of 150 Saybolt units viscosity widely employed as a lubricant for bearing surfaces. Table l shows the compositions of the test lubricants, the proportions of the lubricants and remarks as to the type of wear encountered in each instance.

Table 1 Average Y r Lubricant Coetficient Remarks as to Wear of Friction Surface 100% cetene 0.11 Very high wear as though the surface were machined; Vegetable Oil 0. 27-0 38 Galled badly. 20% methyl stearate, 80% cetene; 0 1 Veryl little wear after 1 our. 30% methyl stcaratc, 70% cctcne 0 1 Polished surface; No

visiblewear. 40% methyl stearate, 60% cetene 0. 1 Do. 50% methyl stearate, 50% cetene- 0. 09 Do. 30% methyl stearate, 70% n- -decene-1 0. 11 D0. 30%isopropylstearate, 70% eetenes 0 l-O. 24 Grooved and gelled in 40 minutes. 20% n-butyl stearate, 80% eetene 0. 14-0 4 Ggoeleed and galled a y. 50% n-butyl stearate, 50% cctcne 0 l2-0. 34 Badly gelled. 100% 150 SUS hydrocarbon oil 0. 2-0 7 Galled. 20% methyl stearate, 80% 150 S US oil 0. 20. Do. 100% eetane l v 0. 4- 0. 68 Galled badly, seized. methyl stem-ate, 70% cetan 0. l4 Galled,

I At all times during the test, the coellieient. of friction was erratic and varied within the limits set forth.

EXAMPLE 3 In this example employing the lubricating test equipment described above in which both the rider and the washer were made of titanium, a mixture of 70% cetene and 30% methyl stearate were introduced as the lubricant mixture in the apparatus. For comparison and as a control a hydrocarbon oil specifically SAE-lO spindle oil was used as a lubricant under the same conditions. After conducting the wear test, it was found that the average coeiiicicnt of friction using the spindle oil was quite crratic and ranged from about 0.56-0.68; the test disc or washer was badly gallcd and caused grooving during the l-hour run. In contrast to this employing the mixture of cetene and methyl stcarate, the average coefiicie'nt of friction was of the 'order of about 0.5-0.6 and the washer showed only a very slight wear track.

EXAMPLE 4 When a mixture of 50% tetradecene-Z is mixed with 30% ethyl tetradccyl ether and this mixture isemployed as alubricant between two surfaces of aluminum that is both the rider and washer were aluminum in the above test equipment, the coefficient of friction is much lower by a magnitude in kind and the wear is materially reduced than when either the aforesaid ether or tetradecene is used separately as the lubricant. The wear is also much less than when a hydrocarbon oil is employed as the lubricant: g

Itwill bev clearly apparent that our compositions can be used not only in bearing applications where a shaft, for instance, is revolving in intimate contact with a stationary member, but they can also be employed in other applications as, for instance, in the cutting of aluminum,

. the extrusion, drawing and stamping of aluminum mem- .in the lubricating art, particularly underfboundary lubricating conditions.

bers, etc. Aluminum cans can be readily drawn to be used for capacitor" casings. Furthermore, billets of aluminum can be passed through dies and the diameter of the billets greatly reduced in size to give aluminum wire which has a shiny appearance and, because of the smooth surfaces of the aluminum, 'reflects the advantageous lubricating characteristics of our lubricating compositions. This ability to impartsmooth shiny surfaces recommends these compositions as polishing materialsfor sole plates of sadirons. Fractional horsepower motors( such asthose described in our copending application Serial No.'1 01,917,

filed April 10, 1961,'and in the continuation-impart filed concurrently herewith based on that application, which by reference are made part of the disclosures of the instant application), using aluminum shafts and bearings can be advantageously lubricatedlwith our lubricating compositionseither alone or dissolved to the desired concentrationin a hydrocarbon lubricating oil.

It will also-be apparent to, those skilled in the art that, instead of the particular olefins and the methyl 'stearate used in the foregoing tests, other-olefins and compounds conforming to Formula I andFormula II may be used without departing fromv thescope of the invention. The proportions of ingredients can of course be varied widely,

and it will also be obvious that other lubricating compositions, many examples of which have been given above, can be combined with our mixture of ingredients comprising the olefinic compound and the compounds of Formula II to give compositions of matter having utility What we claim asnew and desire to secure by Letters Patent of the United States is:

1.;A composition of matter comprising on a weight basis (a) from 5 to of an'olefin having the formula 9 alkyl and linear fluoroalkyl radicals having from 8 to 30 carbon atoms, X is a divalent radical selected from the group consisting of -S- and Z is a monovalentlinear straight-chain saturated aliphatic radical selected from the group consisting of linear ,alkyl radicals having from 11 to 40 carbon atoms and linear fluoroalkyl radicals having from 11 to 40 carbon atoms, and Q is a lower, straight-chain alkyl radical of from 1 to 3 carbon atoms.

2. A lubricating composition of matter comprising by weight, from 5 to 95% methyl stearate and from 95 to 5% cetene.

3L A lubricating composition of matter comprising, by..

silicone, diester, hydrocarbon, polyester, and silicate ester lubricating fluids, and (2) from '10 to 90 parts-of a mixture'of-ingredients comprising on a weight basis (a) from 5 to 95% of an olefin havingthe formula and (b) from 95 to 5% of a compound having the formula whereR is a monovalent radical selected from the class consisting of hydrogen andfluorine, R is a monovalent radical selected from the class consisting of hydrogen fluorine, methyl, monofluoromethyl, difluoromethyl, and trifluoromethyl, R" is a monovalent linear straight-chain alkyl radical selected from the class consisting of linear alkyl and linear fluoroalkyl radicals having'from 8 to 30 carbon atoms, X is a divalent radical selected from the groupconsisting of --O-, -S-

and

and Z is'a monovalent linear straight-chain saturated aliphatic radical selected from the group consisting of linear alkyl radicals having from 11 to 40 carbon atoms and lin-- ear fluoroalkyl radicals having from 11 to 40 carbon atoms, and Q is a lower, straight-chain alkyl radical of from 1 to 3 carbon atomsl 1 g 6. A lubricating composition comprising a mixture of ingredients containing, on a weight basis (1) 100 parts of a lubricating fluid selected from the class consisting of silicone, diester, hydrocarbon, polyester, and silicate ester lubricating fluids, and (2) from to 90-parts of a mixture of ingredients comprising on a weight basis (a) from 5 to 95% methyl stearate, and (b) from 95 to 5% cetene.

7. The method of lubricating two solid surfaces between which there is relative motion, at least one of said surfaces being a metal, which comprises maintaining between the two surfaces a composition of matter comprising on a weight basis (a) from 5 to 95% of an olefin having the formula and (b) from 95 to 5% of a compound having the formula trifluoromethyl, R" is a monovalent linear, straight-chain alkyl radical selected from the class consisting of 'linear alkyl and linear fluoroalkyl radicals having from 8 to carbon atoms,.){ is a divalent. radical selected from the group consisting of 0,

' and Z is a monovalent linear straight-chain saturated aliphatic radical selected from the group consisting of linear alkyl radicals having from ll to 40 carbon atoms and linear fluoroalkyl radicals having from 11 to 40 carbon atoms, and Q is a lower,- straight-chain alkyl radical of from 1 to 3-carbon atoms, and thereafter effecting motion between the two solid surfaces with the mixture of ingredients thereb'etween.

8. The method of lubricating two solid surfaces between which there is relative motion, at least one of said surfaces being a metal selected from the class consisting of aluminum and alloys of aluminum, which comprises main ing between the two surfaces a mixture of ingredients comprising on a weight basis (a) 1510 methyl stearate and (b) from 95 to 5% cetene, and thereafter effecting motion between the two solid surfaces with the mixture of ingredients therebetween.

'9. .The method of lubricating two solid surfaces between which there is relative motion, at least one of said surfaces being a metal selected from the class consisting of aluminum and alloys of aluminum, which comprises maintaining between the two surfaces a mixture of ingredients comprising on a weight basis (a) 5 to 95% methyl stearate and (b) from 95 to 5% decene-l, and

thereafter effecting motion between the two solid surfaces with the mixture of ingredients therebetween.

10. The-method of lubricating two solid surfaces between which there is relative motion, at least one of said surfaces being aluminum, which comprises maintaining between the two surfaces a mixture of ingredients comprising on a weight basis (a) 5 to 95% ethyl tetradecyl ether and (b) from 95 to 5% tetradecene-2, and thereafter effecting motion between the two surfaces with the with the mixture of ingredients therebetween.

11. The process for shaping a metal composition which comprises maintaining a film of lubricant between the metal composition and a shaping member, said lubricant comprising on a weight basis (a) from 5 to 95% of an and '(b) from 9 5 to 5% of a compound having the formula consisting of hydrogen and fluorine, R is a monovalent olefin having the formula where R is a monovalent radical selected from the class radical selected from the class consisting of hydrogen fluorine, methyl, monofluoromethyl, difluoromethyl, and

trifluoromethyl, R" is a monovalent linear, straight-chain alkyl radical selected from the class consisting of linear 11 v a I '12 alkyl and linear fiuoroalkyl radicals having from 8 to 30 12. The process as in claim 11 in which the metal comcarbon atoms, X is a divalent radical selected from the position undergoing shaping is an aluminum composition group consisting of -O, S, selected from the class consisting of aluminum and alloys 0 0 0 v 0 0 of aluminum of which 50%, by weight, is aluminum, ll I5 0 o l] g m g 5 and the lubricant is a mixture comprising, by weight, from 5 to 95% cetene andfrom 95 to 5% methyl-stearate.

and Z is a monoyal'ent-linear straight-chain saturated ali- References Cited by the Examiner phatic radical selected from the group consisting of linear UNITED STATES PATENTS alkyl radicals having from 11 to 40 carbon atoms and 10 2 210140 8/40 colbcth, linear fluoroalkyl radicals having from 11 to 40 carbon 1 2257'969 10/41 Loam 'g 'f"'i 2 atoms, and Q is a lower, straight-chain alkyl radical of 25o0165 v 3/50 Doheny ct from 1 to 3 carbon atoms, and thereafter subjecting the 11/53 Kipp 252* XR metal composition to sufiicient force to create relative. motion between said metal compositionand said shaping 15 1/56 wankat 252 X member and to cause displacement of a portion of said DANIEL primary Examine, metal-composition with respect to the remainder thereof.

Claims

1. A COMPOSITION OF MATTER COMPRISING ON A WEIGHT BASIS (A) FROM 5 TO 95% OF AN OLEFIN HAVING THE FORMULA