US2370299A - Compounded lubricant - Google Patents

Description

Feb. 27, 1945; FARRlNGTON 2,370,299

COMPOUNQED LUBRICANT Original Fi-led 55615, 1937 COEFFICIENT OF FRICTION SPEED- F-T. PER MINUTE KINETlC OILlNESS TESTING MACHINE (PAT.No.2,o2o,565

SurfacesI-Casf iron on Cam Iron. Temperarure 275 F Loadingr I500- lbs./sq.in.

IN VENTOR.

Bruce; B; Farrlhg fbn A 77'0RNEY memes-Feb. 21, 1945 l,

its!) STATES PATENT orrlcs Bruce B. Fan-ington, Berkeley, Calif., assignor to Standard Oil Company 'of California, San Francisco, Cailfl, a corporation of Delaware Continuationgoi' application Serial No. 177,878,'

December 3, 1937. This application February 26, 1941, Serial No. 380,708 a I I srclolms. This invention relates to compounded lubricants. Thepresentapplication is a continuation of my parent application Serial No.- 177 ,8'78, flied December 3; 1937, on Composition of matter and process of lubrication.

- A large number of addition agents have been proposed to improve the lubricating action of mineral oils by reducing, thecoeflicient of friction between metal surfaces to a greater extent than is obtainable with mineral oils alone. The action of these addition agents is in general quite specificand forthe most part unpredictable. An addition agent which is effective to reduce friction between one pair ,of metals at high speeds. will often be found ineiiective to reduce the friction between the same pair of metals at low speeds. In other words, the phenomenon of lu- J brication and reduction of friction is not yet well understood anddevelopments in this field are largely empirical. It is therefore apparent that the actual conditions oi operation encountered in any particular mechanism must be examined critically it the addition agent is to be truly b'eneiicial.

The lubrication" of reciprocating Darts neces sarily involves lubrication at low speeds since the reciprocating elementldecelerates to'and accelerates fromzero speed at eachuend of the stroke.

Since reciprocat g parts are common in all types of machinery, reduction of friction at low speeds approaching zero is of great impprtance as a inbricating problem. The necessity for adequate w lubrication at low speeds isillustrated by the fact that the maximum wear of the cylinder walls of an, internal combustion engine occurs at the upper limit of the piston ring travel where the rubbing speed is low and where ordinary lubricants fail to reduce friction or wear to the same extent as it is reduced in the remaining portion of the piston travel. r

Material reduction of friction at low speeds is a severe requirement of compounded lubricating oilsgparticularly when the'metal surfaces to be lubricated are cast iron on cast iron, steel onsteel, or other pairs of ferrous metal surfaces. It has. been observed that most oilinessagents 'whichixavebeen proposed by the prior'art fail to matepially benefit the action of mineral evils inreducing friction under these extreme condi tions. 1 Accordingly, it is anjobject of this invention to provide a pro'cess for effectively reducingfriction at extremely 'low* rubbing speeds between ferrous metal frictional surfaces. v a

Another object of ithe invention is to provide (elm-50 I a lubricating composition which is especially. ef-

materially reduce the coeiilcient of friction be-' tween metal surfaces at extremely low speeds as well-as at higher speeds. These compounds are esters of a particular type and'may, be illustrated by the following examples:

Alpha hydrozil esters H Y m-d-c-o-iu Betafiydroxv esters H n 1 Rle-c c-0-B1 oi 1'1 8 so In these formulae R1 gnay be hydrogen or an alkyl group; Rn-cornprises along carbon chain.

Examples of'acids having either an alpha or beta or both alpha and beta hydroxyl groups are: Tartaric acid, (CHOH coon): Tartronic acid, cno'n (coon):

Lactic acid, CH3 CHOH QOOH Citric acid, HOOC CHzCOH ,COUH CH:

Mucic acid) "(CI-IOHM, (coon): Malic acid, CHOH cm (coon): l Glycolic acid, cm on coon An essential ell'aracteris ticof the compounds of this invention is that the alcoholic portion of the ester must" comprise a long carbon chain.

chain:

" Decyl a1COhOl,Ql0H2i0H Dodecyl alcohol, CnHuOH Tetradecyl alcohol, C1'4HaOH Cetyl alcohol, CloHszOH 1 Octa'decyl alcohol, CmHa-IOH Ceryl alcohoL'CnHaOI-I v i Myricyl alcohol, CuHnOH f Lanolin alcohol, CuHaOH Oleyl alcohol, clamor-r The following are alcohols having a long carbon "Lorol, .a material containing lauryl alcohol and"- sold by EII. du Pont de Nemours, is a satisfac tory source of long chain alcohols. I

Esters of any of the above types of. acids .in combination with any of the above listed long chain alcohols are regarded as falling within the broad scope of this invention. For example,

decyl tartrate, dodecyl tartrate, tetradecyl tartrate, cetyl tartrate, l'auryl tartrate, octadecyl tartrate, ceryl tartrate, myricyl tartrate, oleyl tartrate' and lanolin tartrate may beused. Similarly, 'decyl lactate, dodecyl lactate, tetradecyl lac- .tate, cetyl lactate, lauryl lactate, octadecyl lactate, ceryl lactate, myricyl lactate, oleyl lactate and lanolin lactate are encompassed in the broad scope of the invention. g

;These esters are prepared from the respective acids and alcohols by the usual esterification reaction: i 7 RC0QH-i-HO.Et-- RCOOR+1120 a W The reaction may be efiected by heating the two constituents and vaporizing the water formed. Dehydration agents such as sulfuric acid may also be utilized to promote the reaction.

The invention also embodies one species of ester' having definitely superior merit as compared with other members of the above described genus. This species is believed to be a new composition of matter which possesses utility for purposes other than a compounding ingredient in lubricating oils. The compound comprises the ments are obtained with as little as 0.1% of the ester or an hydroxy acid, such as previously described, and the alcchbls obtained from sperm oil. 1

Sperm oil comprises esters of several long chain alcohols and hydrolysis of the oil yields a mixture of these alcohols together with fatty acids. The acids and alcohols may be separated by converting the acids to soaps and separating the soaps and alcohols by distillation or extraction with solvents by processes well known in the ester, but it is preferred to add from .5 to 1.5% by weight of the compound. Because the esters are expensive ingredients, it is generally not desirable to add more than about 2% to the lubri cants, although as much as 10% or more may be permissible for various purposes. 4

The esters of this invention may be utilized in mineral lubricating oils of all types, and it should be understood that the term lubricating oil includes highly naphthenic lubricants such as are obtained from California crude oils or highly paraflinic lubricants obtained by solvent refining processes or' from Pennsylvania type crudes.

Likewise, the addition agent will be of utility in oils of widely different .viscosities, ranging from light spindle oils through the usual range of viscosities utilized inordinary internal combustion engines to the highly viscous oils manufactured for gears or heavy machinery.

The discoveries disclosed hereinabove are utilized in the process of this invention by lubricating ferrous metal surfaces, such as cast iron on cast iron, moving in frictional contact at low speeds-relative to each other with a film of lubricating oil and adding an alpha or beta hydroxy ester of long chain alcohols w the lubricant in i order to reduce the coeflicient of friction,

art. The mixture of long chain alcohols so obtained is termed fspermol in the present specification. The exact chemical formulae and relative proportions of the alcohol ingredients of spermol have not-been ascertained, but it is said that sperm oil contains alcohols such as cetyl and octadecyl in minor proportions and an,

alcohol-of the type of oleyl'in larger proportions.

It is to be noted that spermioil is not the equivalent of spermolfi-since the former is a naturally-occurring oil and the latter comprises the natural mixture of alcohols obtained .by hydrolysis of the oil.

Spermol esters of I cially eifective for reducing friction between ferrous' metal surfaces at low speeds.

In order to illustrate theg iefiectiveness of the process and the compositions of this invention, a series of testswas run in a kinetic olliness testing machine of the type disclosed in United States Patent No.- 2,020,565, granted to Neely et al. No-

vember 12, 1935. The data from these tests are.

shown graphically in the drawing. Attention is directed to the fact that esters of shorter chain alcohols are not effective in reducing friction between cast iron surfaces 'at low speeds. This is illustrated by the curve showing the coefflcient of friction atvarious speeds of an oil containing 1% diamyl tartrate.

Esters of; spermol are decidedly superior to esters of various other long chain alcohols falling within'the broader scppe of the invention. This fact is illustrated by data showing .5% of .spermo 1! t be approximately as effective hydroxy' acids are espe- I nor and thereby contribute illustration only and with the intention that the scope of the invention should not be limited- This process is not merely a mechanical one but involves chemical or physico-chemical action, since the added esters are present in a proportion so small that they have no appreciable effect on the viscosity or more mechanical actlon of the lubricant. The reduction of friction effected by the, esters is probably due to their chemical action on the metal surfaces being lubricated, although the esters may also act on the base oil itself in some unknown chemical manto the improved lubrieating action. Y I r Specific embodiments of the invention have been described but this has been done by way of thereby. For example, the generic aspect of this invention includes highly thickened oils, such as castor machine oils containing aluminum naphthenate, or other known thickening agents. The

invention alsoincludes'grease compositions containing soaps of the alkali and/or heavy metals within its generic-scope. It will be apparent that numerous modifications and variations of the 11-- 'lustrated examples may be utilized in the practice i of the invention which is of "the f ollow ing scope of the I claim: L 1. A compounded lubricant, comprising a hydro- I carbon lubricating-oil 'and a smallamount of an H organic ester comprising an aliphatic type alcohol having from 'approximately ten to approxi mately thirty carbon atoms in the chain esterifled' with'nn hydroxy aliphatic 'acid' having at least one hydroxyl group not more than two carbon atoms removed from a carboxyl groupof said alcohol having from approximately. ten to approximately thirty carbon atoms in the chain acid, the proportion of aid ester being sumcient to eiiectivelyfdecrease t between lmetal frictional bin'g speeds. g

2. A compounded lubricant comprising a hydrocarbon lulp'icating oil and a small amount of an organic ester comprising analiphatic type alcohol having from approximately ten to approximately thirty carbon atoms in the chain esterie coeflicicnt of friction surfaces at low rubfled with an aliphatic acid having an hydroxyl group in an alpha'position with respect to a carboxyl group thereof, the proportion of said ester being sufilcient to effectively decrease the coefllcient of friction between metal frictional surfaces. at low rubb g speeds.

3. A compounded l bricant comprising a hyh drocarbon lubricating oil and a small amount of an organic ester comprising an aliphatic type al-.

cohol having frpm approximately ten to approximately thirty carbon atoms in the chain 'esterified with an alphatic acid havingan hydrcxyl group in a beta position with respect. to a carboxyl group thereof, the proportion of said ester being sumcient to, effectively decrease the coeflicient of friction between metal frictional surfaces at low rubbing speeds.

as compounded lubricant comprising a hydrocarbon lubricating oil and a small amountpf tartronic acid estervoi an aliphatic alcohol having from approximately ten to approximately thirty carbon atoms in the chain, the proportion of said ester beingsuflicient to effectively decrease the coeiiicient of friction between metal frictional j surfaces at low rubbing speeds.

5. A compounded flubricant comprising a hydrocarbon lubricating oil and a small amount of a malic acid ester of an aliphatic alcohol having from approximately ten to approximately of said ester being sufficient to effectively decrease the 'coeillcient of friction between metal frictional surfaces at low rubbing speeds.

7. A compounded lubricant comprising a hi esterifled with an aliphatic acid having an hydroxyl groupjin a beta position with respect to a carboxyl group thereof.

10. A compounded lubricant comprising a hydrocarbon lubricating oil and a smallamoumt of an organic ester comprising spermol esterifledwith an hydroxy aliphatic acid having at least one hydroxyl group not more than two carbon atoms removed from a carboxyl group of said acid, the proportion of said ester being suflicient to eflectively decrease the coemcient of friction between metal frictional surfaces at low rubbins speeds.

ll. A compounded lubricant comprising a hydrocarbon lubricating oil and a small amount of an organic ester comprising spermol esterified with an aliphatic acid having an hydroxyl group in an alpha position with respect to a carboxyl group thereof, the proportion of said ester bein suflicient to effectively decrease the coemcientof friction between metal frictional surfaces at low rubbing speeds.

12. A compounded lubricant comprising any-- drocarbon lubricating oil and a small amount of an organic ester comprising spermol esterifled with an aliphatic acid having an hydroxyl group in a beta position with respect to a carboxyl group thereof, the proportion of said ester being suilicient to effectively decrease the coefficient of friction between metal frictional surfaces at low rubbing speeds.

13. A compounded lubricant comprising a hydrocarbon oil and from approximately 0.1% to approximately 10% by weight based on the-oil of "spermol'" tartronate.

.14. A compounded lubricant comprising a, hy-

drocarbon oil and from approximately 0.1% to approximately 10% by weight based on the oil of spermol malate. v

15. A compounded lubricant comprising a hydrocarbon oil and from approximately 0.1% to approximately 10% by weight based on the oil of a spermol ester or glycolic acid.

16. A compounded lubricating oil comprising a petroleum lubricating oil and a small amount of a neutral ester of an aliphatic alcohol having from approximately ten to approximately thirty carbon atoms in the chain and an aliphatic acid containing not more than six carbon atoms and containing an 'hydroxyl substituent not more than drocarbonoil and from approximately 0.1% to approximately 10% by weight based on th of an organic ester comprising an aliphatic type alcohol having from approximately. ten to anon U proximately thirty carbon atomsin the chain esterifled with an hydroxy aliphatic acid having at least one 'hydroxyl group not more than two of said acid. 4

carbon atoms" removed from a carboxyl group 8. A compounded lubricant: comprising a hy-' drocarbon oil and groin approximately 0.l% to approximately 10% by weight based cn'the 'oil of an organic ester comprising an aliphatic type alcohol having from approximately ten to aprubbing speeds.

proximately thirty carboriatoms in the chain droxyl group in an alphaposition with-respect to a. carboxyl group thereof,

9.1 A compounded lubricant'comprising a hy- 'drocarbon oil and from approximately 0.1% to' flDD 1ma e y'1 by weight based on'the' oil of an organic ester comprising an aliphatic type esteritledwith an aliphaticacid having an hytwo carbon atoms removed from a carboxyl group of the acid, the proportion of said ester being sufficient to effectively decrease the coefficient of friction between metal frictional surfaces at low rubbing speeds. I

17. A compounded lubricating oil comprising a petroleum lubricating oil and a small .amount of a neutral ester'of an aliphatic alcohol having from approximately ten to approximately thirty carbon atoms in the chain and an alpha hydroxy aliphatic acid containing not more than six carbon atoms, the proportion of said ester being sufficient to effectively decrease thecoeillcient of friction between metal frictional surfaces at low 18. A compounded lubricating oil comprising a petroleumlubricating oil and a small amount of a neutral ester of an aliphatic alcohol having from approximately ten to'approximately thirty carbon atoms in the chain and a beta hydroxy bon atoms, the proportion of said ester being sufv aliphatic acid containing not more than six carficient to eifectively decreasethe coemciant of with an aliphatic alcohol having Irom mately: ten to approximately thirty carbon atoms 20 drocarbon Y tween metal \fi ncompounded ubricant comprisinga hy-' drocarbon mbricafl drocarbonlubricatilgoilandasmallamountof,

bon atoms removed from a carboxyl group of the acid, the proportion or said ester being suflicient to eilectively decrease the coeflicient or friction 1 between metal frictional surfaces at low. rubbing speeds.

20. A compounded lubricant a hy-' drocarbon lubricating oil and a small amount or an organic ester comprising :an aliphatic poly-- is with "spermoi," the proportion otsaid ester being carboxylic acid having an hydroxyl group notmore than two carbon atomsremovedtromacarboxyl group or the c d. said acid being esterlfled approxiin the chain, the proportion of said ester being sumcient to eflectively decrease the coemcientor friction between 'metal frictional surfaces at low rubbing speeds.

an organic ester comprising an aliphatic polycarboxylic acid having an hsdrosrl group not 26. A= compounded lubricant allphaticp rcarborylicacidhairing anhydrosylgroup alphapositionwithrespecttoatieastone' said carboxy group said acgdbeing estcrined suflicient to' enectiveiy decrease thecoetli'cient of friction between metal frictional surfaces at low rubbing speeds.

2'7. Acompounded lubricant comprising a hyan organic ester comprising an aliphatic.polycarboxylic acid having an hydroxyl group'in a beta-position 'withrespect to at least one or the said-carbon! groups. said acid bein esterii'led 21. A compounded lubricant comprising a hy- .26 with spermol, the proportion or saidester being drocarbon lubricating-oil and a small amount oi an organic ester comprising an aliphatic polycarboxylic acid having an hydronl group in'an alpha position with respect to at leastone of the said carboxyl groups, said acid being esterified with an aliphaticalcohol having from ap-' proximately ten to approximately thirty carbon atoms in the chain, the proportionof said ester beingsuflicient to eflectively decrease the coefflcient of friction between metal frictions-laurfaces at low rubbing speeds. v

.22. A compounded lubricant comprising a hydrocarbon lubricating oil and a small amount of an organic ester comprising an aliphatic polycarboxylic acid having an hydroxyl group in a beta position with respect to at least one of the said carboxyl groups, said acid being esterifled. with an aliphatic alcohol having from approxi-' mately ten to approximately thirty carbon atoms in the chain, the proportion of said ester being sufllcient to eifectively decrease the coeflicient of friction between metal frictional surfaces at low rubbing speeds.

23. A compounded drocarbon lubricating oil and a small amount of an organic ester comprising an aliphatic poly- "carboxylic polyhydroxy acid having at least one hydronl substituenti not more than two carbon lubricant comprising a 117- 50 sumcient to eiiectively decrease .the coeiiicient of friction between metal irietional surfaces at low rubbing speeds zsJicom" edlubricantcomprisingahysubstitue'nt not more than two carbon atoms removed from a carboxyl group oi the acid, said acid being esterifled wifispermol," the pr p rtion of said ester being suiiicient t9 eilectiveiy decrease the peflicient of friction between metal frictional surfaces at low'rubblns speeds.

29. A compounded lubricant comprising a hydrocarbon lubricating oil and from approximately 0.1% to approximately 10% by weight based on 1 the' oil or anorganiccster comprising an allphatic poly arbmlic acid having an hydroxyi 5 group not more than two carbon atoms removed from a'carboxyl group of the acid, said acid'beins esterified with an aliphatic alcohol having from approximately ten to approximately thirty.carbon atomsinthe chain.

30. A compounded lubricant comprising a hydrocarbon lubricating oil and from approximately 0.1% to approximately 10% by-weight based on the oil or an organic ester comprising an ali-' phatic polycarboxylio acid having an hydroxyl atoms removed from-a carboxyl group obthe 5 my: an alpha Mum with-respect to oilandasmallamountot an organic'estercmnprisinz sportsman- .phatic acid having at lust'me1 hydroxyl group not more than two carbqnmtmns;

ass-com ute lubricant comprising earboxyl groups, said acid coml i iialu-;- oilanda-small-amounto lubricating oil and a mall amount or bon atoms removed from a carboxyl group of the acid, said acid being esterifled with an aliphatic alcohol having from approximately ten to approximately thirty carbon atoms in the chain.

33. A compounded lubricant comprising a hydrocarbon lubricating oil and from approximately 0.1% to approximately 10% by weight based on the oil of an organic ester comprising a polyhydroxy aliphatic polycarboxylic acid having at least one hydroxyl group not more than two carbon atoms removed from a carboxyl group thereof, said acid being esterifled with an aliphatic. a1- cohol having from approximately ten to approximately thirty carbon atoms in the chain;

34. A compounded lubricating oil comprising a petroleum lubricating oil and a small amount of a neutral ester of an aliphatic alcohol having from approximately ten to approximately thirty carbon atoms in the chain and an aliphatic polycarboxylic acid containing not more than three carboxyl groups and not more than six carbon atoms and containing an hydroxyl substituent' not more than two carbon atoms removed from a carboxyl group of the acid, the proportion of said ester being suillcient to effectively decrease the coefllcient of friction between metal fric-' tional surfaces at low rubbing speeds.

35. A compounded lubricating oil comprising a petroleum lubricating oil and a small amount carbon atoms in the chain and a beta, hydroxy three carboxyl groups and "not more than six carbon atoms and containing an hydroxyl substituent not more than two carbon atoms removed from a carboxyl group of the acid, the proportion of said ester being sufficient to efiectively decrease the coeflicient of friction between metal frictional surfaces at low rubbing speeds.

BRUQE B. GTON.

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