US3297574A - Lubricating compositions containing ep agents - Google Patents

Description

United States Patent 3,297,574 LUBRICATING COMPOSITIONS CONTAINING EP AGENTS Alexander C. B. MacPhail, Little Sutton, Francis T. Bar- The chlorinated polyaryl compounds described as additive (B) above are used in concentrations between about 0.5% and about 10% by weight and preferably between 1% and 6% by Weight of the lubricating oil croft, Upton-by-Chester, and Charles B. Milne, Little compositions. Compounds of this type include chlori- Sutton, England, assignors to Shell Oil Company, New nated and fluorinated diphenyl, triphenyl, tet-raphenyl, York, N.Y., a corporation of Delaware pentaphenyl, phenylnaphthyl and mixtures thereof. The N h File?! 20, 1964, 333,583 halogen content of these compounds varies from 20% Chums Priomy, g g gg Britain, 21, 1963, to 80% by weight, preferably 40% to 70% by weight. t A class of compounds of this type are commercially 7 Claims 232-465) 10 available under the trade name Aroclor from Mon- This invention relates to synthetic lubricating composisanto Chemical Company. Particularly preferred are tions capable of functioning over a wide temperature r ted (40-70%) diphenyls commercially availrange and under extreme pressure and wear conditions. a l as Aroclor 1254 and ArOCl-Or 1 the former More particularly the invention relates to synthetic ester being a Chlorinated p nyL Although these C0111- base lubricating compositions which are stable and possess pounds h m lv pr desirable x r pr r excellent extreme pressure and .anti a ti characteristics in synthetic lubricating oils, the desirable It is known that esters of mono o polyhydric l effects of these compounds do not substantially increase h d li h i di -b li id h as di(2 h 1- with a corresponding increase of additive concentration. hexyl)sebacate or esters of pentaerythritol and mono- In other Words, although the addition of a Small amount carboxylic acids such as C aliphatic carboxylic acids of these Compounds imparts desirable Properties t0 the are acceptable base oils for aircraft gas turbine engines 011, addition of increased amounts does hht Produce the when inhibited with suitable antioxidants such as phenoexpected further increase in eXtTeme Pressure P p thiazine. However, lubricants of this type lack desired ties- The low fate of increase of scuffing load with extreme pressure and antiwea properties d attempts creasing Arochlor concentration is shown in Tables I to incorporate conventional extreme pressure agents such and EXampleS II-IV belowas organic phosphates or thiophosphates, sulfur-contain- I11 accord with the Present invention, the eXtTeme P ing compounds and the like have met with little success. Sure effect of the Chlorinated p y y compounds is 6011- It is an object of the present invention to provide imsidefahly enhanced y the addition of to 10%, P proved high-temperature synthetic lubricating composierably 1 to 6% by weight of the lubricating oil comtions. It is a further object of this invention to provide position, of a triaryl ester of phosphorothionic acid (ad stable gas turbine engine synthetic lubricants With excelditive (C) above). Addition of the prescribed amount t extreme Pressure and ahttwear P P t other of these esters surprisingly increases the efiectiveness of Q J W111 h h pp from the tonowlhg P" the chlorinated polyaryl additive; i.e., as the concentratlon of the mvennon' tion of chlorinated polyaryl is increased in the presence $2 3 5 f z g dlscqveredt g if m a of a constant amount of triaryl phosphorothionate, there p are lmpar 0 an 3 an is a corresponding large increase in anti-scutt properties. ester lubrrcatmg 011 by the additlon of mmor amounts Th th f th d of each of (1) a chlorinated polyaryl compound and 6 com ma O asefa mves i uces T' llent extreme-pressure propertles not attainable with (2) a trraryl ester of phosphorothiomc 301d. More spe- 40 Ce cificauy, improved lubricating Compositions of the the conventional chlorinated polyaryl additive alone. In vention comprise; Tables I and H, Examples VI-VIII below, 1t 1s shown A aliphatic carboxylic lubricating base; that the rate of increase of scufimg load with increas- (B) A minor amount f one or more chlorinated balsa ing Arochlor concentration in the presence of 2% triaryl hydrocarbon represented by th f l phenyl phosphorothionate is considerably higher than in the absence of this compound. The resulting lubricat- Ar-Ar ing oil has excellent extreme-pressure properties which \J (31y are only available with the use of the phosphorothionate Where Ar is a mono or polynuclear aromatic hydrocar- 5O additive bon such as benzene, naphthalene, or anthracene, prefisfaveml W1th varymg Arochlor P eramy at least one f which is benzene x and y are tration, with and without tnphenyl phosphorothionate, integers of f 1 to 3 and f bl f 2 to 4, the were tested for their load-carrying capacity on an I.A.E. chlorine atoms being attached directly to the carbon atoms Gear Rig as described in the Institute Of P l um of the aromatic nuclei, and z is an integer from 1 to 10, Method 166/60T using BSSEN34 Steel gears and P preferably from 1 to 4; and ating at an oil temperature of V. or C. The (C) A minor amount of a triaryl ester of phosphoromean failure loads at 2000 r.-p.m. and 6000 rpm. were thionic acid, each aryl group containing 6 to 10 carbon determined for the compositions of Table I and are shown atoms. in Table II.

TABLE I Composition of Example I II III IV V VI VII VIII Di(isooety1 azelate), percent w 100. 0 94. 0 95.0 92. 0 95.0 92. 0 Aroclor 1254 (chlorinated diphenyl), percentw 3.0 5.0 8.0 3.0 Triphenyl phosphorothionate, percent w- 2.0 2.0 3,7-Dioctyl phenothiazine, percent w 1. 5 1.5 1. 5 5-Methyl benzotriazole, p.p.m 25 25 25 D.C. ZOO/12,000 silicone, p.p m 5 5 5 Phenyl-a-naphthylamine, percent w 1. 5 1. 5 1. 5

which are dipentaerythritol esters of an alkanoic acid selected from the group consisting of alkanoic acids having from to carbon atoms and mixtures of alkanoic acids having from 2 to 12 carbon atoms in proportions to provide an average chain length of from 5 to 10 carbon TABLE II Example I II III Iv v VI VII VIII I.A.E. Scufiing Load, lbs.:

2,000 r.p.m.

60 0. 45 55 70 75 90 100 110 120 110 o 45 74 70 75 so 105 110 120 '%6 "f" a5 45 47 50 40 40 c5 s5 110 0. 25 34 37 40 45 30 60 85 Sum of sending loads, lbs 150 208 224 240 255 275 345 410 Increase of sculfing loads with increas g Aroclor concentration 5s 16 16 20 70 65 Rate of increase of scuffing load per 1% increase in Aroclor concentration 19 8 5 7 35 22 Examples of triaryl esters of phosphorothionic acid suitatoms. Hcrcolube A and Hercolube C (Cg-C10 and able for use in compositions of the invention are triphenyl C -C acid esters of pentaerythritol) and Hercoluhe phosphorothionate, tritolyl phosphorthinate, tribenzyl F (C -C acid esters of dipentaerythritol) are partlcphosphorothionate, and trixylyl phosphorthionate. The ularly useful base oils for the additives of the invention. preferred ester is triphenyl phosphorothionate. The aliphatic carboxylic acid esters need not necessarily The aliphatic carboxylic acid ester lubricating oil be simple esters or mixtures thereof but may be what are bases which are used in lubricating oil compositions termed complex esters made by esterifying in one or according to the invention may be esters of a monomore stages, an aliphatic dicarboxylic acid and a glycol hydric aliphatic alcohol having from 3 to 18 arbon or polyglycol optionally together with an aliphatic monoatoms in the molecule, with a monobasic aliphatic acid CaI'bOXYIiC acid and/01' an aliphatic monohydri? alcoholhaving from 4 to 18 carbon atoms in the molecule, for 25 A typical complex ester is that made by esterifying two example isodecyl pelargonate, moles of an aliphatic dicarboxylic acid, one mole of a A further class of aliphatic carboxylic acid esters which glycol P y y and two moles of an aliphatic mono may be used is the aliphatic esters of monobasic carboxylic hydfic 31601101 having a formula! acids having from 4 to 18 carbon atoms and a glycol R OOCR COOROOCR COOR g z ggg 2 x ?igfiigfi figgfj gig iiggi f ggs wherein R is an alkylene or oxyalkylene group, R is an dipropylene glycol, with heptylic acid, n-octoic acid and alkylene group and R2 15 an alkyl group pelaroonic acii Preferred complex esters of the type are those wherein A particularly preferred class of aliphatic acid esters R 18 an alkylene oxyalkylene group having from 2 to 20 for use in the lubricating oil compositions of the invencarPon R118 an alkylene group opnonally branyhed tion is the aliphatic diester of diabasic carboxylic acids fig havmg t to 20 g f fi i and R2 i having 6 to 20 carbon atoms and monohydric alcohols a Y group prefera y branc e c amed and especla y having from 1 to 12 carbon atoms, for example esters gg gg fi g giz i gg gf g beta carbon atom of adi ic acid, imelic acid, suberic acid, azelaic acid and sebacif: acid wi t h lauryl alcohol, heptyl alcohol, octyl al- 40 tures of g g q i t i ig cargoxyhc cohol and nonyl alcohol. Particularly preferred aliphatic .esters f a so m e u F 5 diesters of dicarboxylic acids are those derived from pqsmons accor mg tot Especla.y Sulta monohydric alcohols having a branched chain, for exammixtures are those of l ahphatlc estefs of dlcarboxyhc ple 2-ethyl hexanol and especially those having no hydroacids gg q %g i, alcholls and i gen on the beta carbon atom, for example 2,2-dimethy1 g i f g b l esters. pentanol, 2,2,4-trimethyl pentanol, 2,2,3-trimethyl pentat e O w t e u ncatm" i' 1101 2 2-dimethylhexanol and Z-methyl-Z-ethyl hexanol. y which is especlauyyalpable p. the .lubncatmg As examples of other aliphatic carboxylic acid esters 1S rfgqulred the lubncation of Brftlsh i f turbme which may be used there are mentioned aliphatic esters engines opfratmg on a lubricant havmg a vlscoslty of of monocarboxylic acids having from 3 to 10 carbon at 210 atoms, for example, propionic acid, butyric acid, valeric lubncatmg O11 compolilons of i myentlon i acid, capric acid, caprylic acid, lauric acid and pelargonic coptaln any of t 5 addltlves for ahphfmc carboxylic acid and POIYOISTOI. example, pentaerythritol, dipantatenh ac d ester lubricating OllS, for example thickeners, antithritol and trimethylolpropane oxidants, antilacqnermg agents, ant -foaming agents, dyes, Examples of Such esters are pentaerythrityl butyrate, anti-corrosion agents metal decativators and addmonal pentaerythrityl tetrabutyrate, pentaerythrityl tetravalerate, eXtremePYeSwm addmves If necessary pentaerythrityl tetracaproate, pentaerythrityl dibutyrate- As tlllckeners there be used polyalkylene glycols dicaproate, pentaerythrityl butyratecaproate divalerate, and the. mono and dl'ethers esters havmg the pentaerythrityl butyrate trivalerate, pentaerythrityl butyr eral formula ate tricaproate, pentaerythrityl tributyratecaproate, mixed RIO (R1O)II R3 C saturated fatty acid esters of pentaerythritol, dipenwherein R and R each represent a hydrogen atom, a taerythrityl hexavalerate, dipentaerythrityl hexacaproate, non-aromatic hydrocarbon radical or an acyl group, R dipentaerythrityl hexaheptoate, dipentaerythrityl hexacaprepresents an alkylene radical and n represents an integer. rylate, dipentaerythrityl tributyratecaproate, dipentatery- In the polyoxyalkylene chain -(R O) the radical R thrityl trivalerate trinonylate, dipentaerythrityl mixed may be an alkylene radical, preferably an alkylene radihexaesters of C fatty acids and trimethylolpropane cal with two to eight carbon atoms. Still more preferred .heptylate. polyalkylenetglycols are those wherein the alkylene radi- A class of pentaerythritol esters useful as base oils are cal is an ethylene or propylene radical. In the poly- Hercules Hercofiex and "Herc0lube pentaerythritol oxyalkylene chain (R O) there may be present st s S ch as H fi 600 and Hercolube I69 70 alkylene radicals with different numbers of carbon atoms The chain may, for instance, consist of both oxyethylene and oxypropylene radicals. In the instance where the polyoxyalkylene chain contains different alkylene radicals, --these may be randomly distributed throughout the molecule or may be arranged in regularly recurring units or blocks, each consisting of one or a plurality of similar oxyalkylene radicals. Particularly preferred polyalkylene glycols are those having blocks of, for example, 1 to 8 oxyethylene radicals alternating With blocks of, for example, 1 to 8 oxypropylene radicals.

In those cases where the radicals represented in the above general formula by R and/ or R are hydrocarbon radicals, the radicals may be saturated or unsaturated, straight chained or branched, or similar or dissimilar, nonaromatic hydrocarbon radicals. A particular preference is given to polyalkylene glycols in which R is hydrogen and R is an alkyl group such as a propyl, butyl, pentyl or decyl group.

In those cases where the radicals R and/ or R are acyl radicals, the radicals may be derived from any carboxylic acid. Preference is given to the alkane or alkene monocarboxylic acids such as acetic acid, propionic acid, butyric acid, lauric acid, stearic acid and oleic acid.

The molecular weight of the polyalkylene glycols may vary over a wide range but preferably is from 350 to about 10,000; molecular weights between 800 and 6,000 are particularly preferred. The polyalkylene glycol thickener may be used in a concentration of between 5% and 50%, preferably between and 40% based on the whole composition.

Suitable polyalkylene glycols are those sold under the name Ucon Fluids (the word Ucon is a Registered Trademark) manufactured by the Carbide and Chemical Corporation and Oxilube the word Oxilube is a trademark) manufactured by Shell Internationale Chemical Company and are described in US. Patents 2,425,755, 2,425,845 and 2,952,335. Ucon fluids of the LBX series made by copolymerizing ethylene oxide and 1,2- propylene oxide and having viscosities (at 100 F.) of about 140 and 370 cs. respectively have been found to give excellent results.

As antioxidants Which may be used in the lubricating oil composition according to the invention there are mentioned alkylated phenols, for example 2,6-ditertiary butyl- 4-methyl phenol, alkylated bisphenols, for example 4,4'- methylene bis(2,6-ditertiary butyl phenol), aromatic amines, for example phenyl-wnaphthylamine, phenyl-B- naphthylarnine, diphe-nylamine and alkyl substituted derivatives thereof.

An especially preferred class of antioxidants is the thiodiarylamines, for example phenothiazine and 3,6-dioctylphenothiazine. Mixtures of antioxidants may also be used, particularly mixtures of thiodiarylamines and diarylamines, for example a mixture of phenothiazine and phenyl-a-naphthylamine.

Other optional additives for the present lubricating oil compositions are anti-foaming agents, for example polydimethylsiloxanes having viscosities from 100100,000 cs. at C., anti-corrosion agents, and metal deactivators, for example benzotriazole and S-methylbenzotriazole.

We claim our invention:

1. A synthetic lubricating oil comprising (1) a major amount of an aliphatic carboxylic acid ester oil base,

6 (2) about 0.5% to about 10% by weight of a chlorinated polyaryl hydrocarbon having the formula Where Ar is selected from the group consisting of monoand polynuclear aromatics, x and y are integers of from 1 to 8, and z is an integer of from 1 to 10, and

(3) about 0.5% to about 10% by weight of a triaryl ester of phosphorothionic acid, each aryl group having 6 to 10 carbon atoms.

2. The synthetic lubricating oil composition of claim 1 wherein the triaryl ester of phosphorothionic acid is triphenyl phosphorothionate.

3. The composition of claim 1 wherein the aliphatic carboxylicacid ester oil base consists essentially of an aliphatic diester of dibasic carboxylic acids having from 6 to 20 carbon atoms and monohydric alcohols having from 1 to 12 carbon atoms.

4. A synthetic lubricating oil composition comprising (1) a major amount of an aliphatic carboxylic acid ester oil base,

(2) about 0.5 to about 10% by weight of a chlorinated polyaryl hydrocarbon having the formula wherein Ar is an aromatic hydrocarbon selected from the group consisting of benzene, naphthalene, and anthracene, x and y are integers of from 1 to 8, and z is an integer of from 1 to 10, and

(3) about 1% to 6% by weight of a triaryl ester of phosphorothionic acid, each aryl group having 6 to 10 carbon atoms.

5. The composition of claim 4 wherein the triaryl ester of phosphorothionic acid is triphenyl phosphorothionate.

6. The composition of claim 4 containing an antioxidant selected from the group consisting of 2,6-ditertiary butyl-4-methyl phenol; 4,4'-methylene bis(2,6-d.itertiary butyl phenol), phenyl a-naphthylamine, phenyl S-naphthylamine, diphenylamine, phenothiazine, and 3,6-dioctylphenothiazine.

7. A synthetic lubricating oil comprising a major amount of an aliphatic carboxylic acid ester oil base, 0.5 to 10% by weight of diphenyls containing 40 to by weight chlorine, and l to 6% by weight of triphenyl phosphorothionate.

References Cited by the Examiner UNITED STATES PATENTS 2,157,452 5/1939 Humphreys 25246.6 2,242,260 5/ 1941 Prutton 25246.7 2,820,766 1/1958 Elliott et al. 25246.6 3,030,304 4/1962 Elliott et al. 25246.7 3,218,256 11/1965 Edwards et al 25247.5

DANIEL E. WYMAN, Primary Examiner,

L. G. XIARHQS, Assistant Examiner,

Claims (1)

1. A SYNTHETIC LUBRICATING OIL COMPRISING (1) A MAJOR AMOUNT OF AN ALIPHATIC CARBOXYLIC ACID ESTER OIL BASE, (2) ABOUT 0.5% TO ABOUT 10% BY WEIGHT OF A CHLORINATED POLYARYL HYDROCARBON HAVING THE FORMULA