CA2183811A1

CA2183811A1 - Polyurea-thickened grease composition

Info

Publication number: CA2183811A1
Application number: CA002183811A
Authority: CA
Inventors: Patricia Rachelle Todd
Original assignee: Lubrizol Corp
Current assignee: Lubrizol Corp
Priority date: 1995-08-24
Filing date: 1996-08-21
Publication date: 1997-02-25
Also published as: EP0761806B1; JP3998742B2; JP2007100107A; AU721723B2; AU6194496A; ES2166867T3; DE69616458T2; JPH09104889A; DE69616458D1; EP0761806A1; SG72700A1

Abstract

A grease composition comprising: a major amount of an oil of lubricating viscosiey; a thickener selected from the group consisting of monoureas, diureas,triureas and polyureas, or mixtures thereof; and an oil soluble neutral or overbased zinc salt of a carboxylic acid selected from the group consisting of zinc salts of fatty acids, the zinc salts of hydrocarbyl-substituted salicylic acids, and zinc glyoxylates is disclosed.

Description

21~3811 TITLE: POLYUREA-THICKENED GREASE COMPOSITION
Tbis invention relates to a urea-thickened grease ,o~ .OD;liul~. More pal~i~,ulally~ it relates to a urea-thickened grease ~ cûntaining oil-soluble zjnc ~allJU~ ,D.
BA~'XC`ROUND OF TRF T~vEN~ON
Grease ~ have been known for a long time. Classically, greases have contained an oil of lubricating viscosity and a thickening agent. Thickening agents have ûften been soaps, such as the metallic salts of fatty acids. CalGium soaps, 10 as grease-thickening agents, have a long history. More recently, complex greasGs have been developed which use a l ' ' of a salt of a long chain acid, such as stearic acid, and a salt of a short chain acid, such as acetic acid to form a thickening metallic salt soap. Calcium is typical metallic counter ion for this type of grease.
Sodium, lithium, and aluminum have been used to form soaps which aGt as grease 15 thickeners. 0l~ u~Jllil;G bentonite clays have been used as grease thickeners. More recently, ureas have been used as grease thickeners. The ureas are prepared by reacting an isoGyanate with an amine. Monoureas may be prepared by reacting a I~IOIIU;DUUY with a "nlln,", 9 Polyureas are prepared by reaGting ~ ' -of diamines, "."~ , J;;,u.,,. , and mOnoiSOGyanateS. A common reaction20 mrxture includes a ~ .t~" a diamine and a ll.~ ""~. The 1 ~lln~ iS
included in the reaction mixture since it acts to terminate the polymer chain and prevents it from becoming too long. The basic reaGtion is illustrated by the following equation:

2 MA + 2 DI + DA ---- ~ MA-DI-DA-DI-MA
Tetraurea MA = Mnm~ e DI=D-- ~
DA = Diamine Additives are frequently added to grease to improve various p~.ru~ll~.~t;
30 properties. Among the properties wbich may be improved through the use of additives are oxidation stability, water resistance, rust protection, corrosion . , ........ . . _ ... , .. . . , _ _ .

. ~ 2183811 protection, antiwear, extreme pressure, ~dl.~;~ , color, oil separation, low Lt~ ul~ flow, and high l~ a~ul~ p~, r~ . Salicylates have been used in grease ~.f.,~ , some times as part of a complex grease, and some times as additives.
Chinese Patents 1052890 and 1052891, as abstracted in the Derwent Database under the numbers WPI ACC NO 92-124047/16 and 92-124048/16, disclose lubricating greases containing a thickening agent which includes lithium 12-hydroxy-stearate and lithium salicylate. The salicylate appears to be an I~ d salicylate and is said to be part of the thickening agent.
U.S. Patent 3,660,288 discloses a polyurea grease containing the magnesium salts of 1l.~ ,u~d fatty acids. The alkali metal, other alkaline earth metal and zinc salts of rincinoleic acid were tested in the ~ )ùa;~iùll, but did not impart the desired rust resistance U.S. Patent 3,711,407 discloses a grease ~ containing an alkali metal salt of IY~IW~YIJ~U;C acid. The salt is oil insoluble and forms in small particles evenly distributed throughout the .,r~
U.S. Patent 3,846,314 discloses a polyurea grease ..I~ I.o~ l-l. containing an alkaline earth aliphatic ~alb~ y' , especially calcium acetate.
U.S. Patent 3,846,315 discloses polyurea greases çontaining alkaline earth 20 metal 1-3 carbon Illùllùcdlb(J;~
U.S. Patent 3,868,329 discloses a polyurea grease ~ .u- ~ . containing an alkaline earth metal aliphatic Illvllu-,albuAylG~ containing from I to 3 carbon atorns Calcium acetate is preferred. The ~.ù~ , also includes a Mannich base.
U.S. Patent 3,983,041 discloses a polyurea grease which contains an alkaline 25 earth carbonate or an alkaline earth lower ~,albu~yla~. The alkaline earth salts serve as rust inhibitors.
U.S. Patent 5,246,605 discloses a polyurea grease containing antimony ylJi~lliû~ The antimûny salt provides extreme pressure and antiwear properties tû the grease.
~ .. , . .. . . .. ~ .

2~8381 1 U.S. Patent 4,719,023 discloses a grease u~ which comprises a base fiuid, a thickener, a calcium salicylate and a magnesium salicylate. The salicylates may be neutral but are preferably overbased alkyl salicylates. The calcium salicylate improves anti-rust properties, and the magnesium salicvlate ..u~ the decrease in dropping point caused by the addition of the calcium salicylate. The thickener may be a substituted urea; however, the preferred thickening agent is an alkali fatty acid soap.
U.S. Patent 4,828,733 discloses greases containing the cuprous salt of 4-llydlu~yl)~ ùic acid (salicylic acid is 2-ll~J~u~ci~uic acid). The salts are primarily o ' E[owever, friction-reducing and wear protection are also disclosed.
U.S. Patent 4,929,369 discloses a grease which may be thickened with polyurea and which includes a alu.iuv ' salt of a carboxylic acid in which the -COOEI group is attached to a riag atom of a fused ring system.
U.S. Patent 5,011,617 discloses a polyurea-thickened grease and an alkaline earth salt of a 1-3 carbon aliphatic IllUllV(,albU~ia~
U.S. Patent 5,084,193 discloses a polyurea grease which contains in addition a simple or complex calcium soap as a further thickener.
U.S. Patent 5,207,935 discloses a polyurea grease containing a calcium, barium, magnesium or zinc salt of an " yl~u~,.,;. ic acid, such as dûd~r,~ yl~
acid in UUilllJ;lld~;UI~ with a sulfonate. The succinic salt acts as a rust inhibitor and texture improver.
Japanese Patent 3û35091 disdoses greases thickened with lithium and sodium soaps which include a wide variety of anti-static agents including m~gnPci.lm oleate, copper oleate and chromium alkyl~ali.,~' Japanese Patent 57212297 discloses a lithium grease which includes alkaline earth salicylates.
British Patent 2,215,346 discloses grease ~u...~!o,;~iu..s thickened with lithium soap, lithium borate, lithium hydroxy-benzoate and a polyol. The lithium hydroxy-benzoate is either the lithium salt of a hydroxy-benzoic acid or the lithium salt of a low alcohol ester of such an acid.
EP Patent 84,910 discloses a lithium complex grease ~ ;ol~ which includes lithium salicylate as a ~ ,, agent.
EP Patent 151,825 discloses a continuous process for - .".r~. I,,,;.,p lubricating greases in which the thickener is a soap and various ','~'''I'l',''''P. agents, such as acetic and salicylic acid, may be added.
EP Patent 566,326 discloses a polyurea grease with molybdenum dialkyldithiUi llc A ~ ' and ashless " ' r~ ~ ~ ' as additives.
0 Soviet Patent SU 924û89 discloses a grease containing a high ash calcium all yl~ali-,ylde. The calcium " y' ' ylaie prevents ~ldLiri~,a~iol~.
U.S. Patent 2,933,520 to Bader relates to compounds represented by the formula:
IRI
HO--Ar--I--Ar--OH
Rl2 COOH
in which Rl may be ~IyJIu-,al~ul~ haloge4 such a chlorine or the like, and R2 is llyJIul,a~bùl~ e.g., allcylene, other than methylene, contairling at least two carbon atorns such as ethyl, propyl, butyl, with either normal, or branched ohains arld containing, for example, up to 10, 12 or even more carbon atoms. The Ar groups are aromatic rings.
They may be 1 " ,~ , it~ , but one or both thereof can contain ~ Ilrl 11~ such as alkyl (rnethyl, ethyl, propyl, butyl, isopropyl, isobutyl), halogen, (chlorine, bromine), nitrO, sulfo and others. The nature of each of these groups affecting properties such as boiling point, solubility, toxicity, and bactericidal, fungicidal, insecticidal and like properties.

2~8381~
U.S. Patent 3,133,944 to Christensen teaches heavy metal salts represented by:
Rl I

COOM
wherein the Rl is an alkyl of 1-4 carbons, R2 is an aUcylene of 2-6 carbons and Ar is am 5 aromatic group which may be substituted with one or more methyl groups and others.
The salts are said to be adapted to retard or prevent the growth of biological organisms, particularly molds and mildews.
U.S. Patent 5,356,546 relates to metal salts of the general formula:
AY~Y (I) wherein M represents one or more metal ions, y is the total valence of aU M, amd A
represents one or more anion containing groups having a total of about y individual anionic moieties and each anion containing group is a group ofthe formula:
~I
Rm~ Rl 2 O
/Ar c c e--O
- R3 -x Zc--f~r--Tt -~m wherein T is an organic group selected from a group of structures, t is (~ or 1, R is an alkyl, alkenyl or aryl group contairling at least 8 carbon atoms, Rl, R2, and R3 are i. ,,l~ l~ " 1. . ,lly H or a hydrocarbyl group, m is an mte$er from 1 to 10, c is am imteger such that the sum of m, c and t does not exceed the valence capacity of Ar, and Z is OX OR., or O~. The salts f~nd utility in lubricants and fuels ~ IIIA
_ _ _ _ _ . _ _ _ _ _,, . , . ., _ _, . ,,, ,,, _, _ , . ,, . , . , _ _ _ _ ~, 218381 ~

SUMMARY OF TEIE INV~NTION
A grease ~ o~ u,. l ;~ .~ a major amount of an oil of lubricating viscosity; a thickener selected from the group consisting of monoureas, diureas,5 triureas and polyureas, or mixtures thereof; and an oil soluble neutrai or overbased zinc salt of a carboxylic acid selected from the group consisting of zinc salts of fatty acids, the zinc salts of ~lyJIu~,albyl-substituted salicylic acids, and zinc glyoxylates is disclosed.
D_T~TT.Fn I~F.C(~RTPTION QF T~F ~vF~TIoN
Surprisingly, it has been found that the oil-soluble zinc calbw ykllf~i~ act as antiwear additives in urea-thickened greases. The preferred oil-soluble zinc f~albu~ yl~ are the saits of fatty acids, the salts of l~yd~uc~lbyl-substituted salicylic acids, and the salts of the reaction product of glyoxylic acid and hydrocarbyl substituted phenols, herein referred to as zinc glyoxylates. The term zinc glyoxylates 15 is used describe the zinc salts of the bis (~ v~,alb,yl substituted IIYdIUAY~IIYI) acetic acids produced in the reaction between the glyoxyliG acid and a phenol As will be set forth more fully below, the zinc ~..I,u~l<.i~., are neutral, to moderately overbased, and the urea greases may be thickened monourea, diurea, triurea, ûr polyurea thickeners. Moderately over based means a conversion of 20 between lû0 and 200.
The term ''}ydlul,~ yl'' is used herein to include:
(I) IIJ~ilu~,~uiJyl groups, that is, aliphatic (e.g., alkyl or alkenyl), aiicyclic (e.g, cycloaikyl, ~;yl ~ " Jl), aromatic, aliphatic- and aiicyclic-substituted aromatic groups and the like as well as cyclic groups wherein the ring is completed through 25 another portion of the molecule (that is, any two indicated groups may together for n an alicyclic group);
(2) substituted il1dlu~ byl groups, that is, those groups containing non-l~ydlu~.~llbul. groups which, in the context of this invention, do not aiter the predom-inantly lly~ilul,~llbyl nature of the lydlùf,cllJyl group; those skilled in the art will be .. .. . . . ...... . . .. . . . .

~ 218381 ~

aware of such groups, examples of which include ether, oxo, halo (e.g., chloro and fiuoro), alkoxyl, mercapto, " yl~ .aylO, nitro, nitroso, sulfoxy, etc.;
(3) hetero groups, that is, groups which, while having ~.~' 'S' llyJlul,allyl character within the context of this invention, contain other than carbon 5 in a ring or chain other vise composed of carbon atoms. Suitable 1~ . ua~UIl~ will be apparent to those of skill in the art and include, for example, sulfur, oxygen, nitrogen and such ~ as pyridyl, furamyl, thiophenyl, imidazolyl, etc.
In general, no more than about three - ' JJ~u~albull groups or I~ IUG~U~
and preferably no more than one, will be present for each ten carbon atoms in a 10 llyJIu~,a~lJyl group. Typically, there will be no such groups or heteroatoms in a llydlu~,allJyl group and it will, therefore, be purely 1IyJlu~.albyl.
The lyJlO~,albyl groups are preferably free from acetylenic ~
ethylenic l...~-l.,.,.l;. ..~, when present, will generally be such that there is no more than one ethylenic linkage present for every ten carbon-to-carbon bonds. The ll~Jlucalb~l 15 groups are often completely saturated and therefore contain no ethylenic ",,~_~",~1;....
Overbased salts of organic acids are widely known to those of sldll in the art and generally include metal salts wherein the atnount of metal present in them exceeds the ,tl-; l",,.. - .~ ;. amount. Such salts are said to have conversion levels m excess of lû0 C~.e., 20 they comprise more than 100% of the theoretical amount of metal needed to convert the acid to its "normal" or "neutral" salt). Such salts are of en said to have metal ratios in excess of one Cl.e., the ratio of equivalents of metal to equivalents of organic acid present in the salt is greater than that required to provide the normal or neutral salt which required only a ' ratio of 1:1). They are comrnonly referred to as overbased, 2s hyperbased or superbased salts. The zinc salts useful in the present invention are moderately overbased, that is, they have a conversion between 100 and 200.

. ... . .. ..... .. . . ... . ..

The i ~ "metal ratio" is used in the prior art and herein to designate the ratio of the total chemical equivalents of the metal m the overbased salt to the chemical equivalents of the metal in the salt which would be expected to result in the reaction between the organic acid to be overbased and the basically-reacting metal compound s according to the known chemical reactivity and ~u~ y ofthe two reactants. Thus, in a normal or neutral salt the metal ratio is one, and in an overbased salt the metal ratio is greater than one.

A. ~FI~ ~IF.A.Cl~ T~TCKl~NF.RS
The greases used in the present invention are thickened with various o substituted ureas. The ureas are mono-, di-, tri- or polyureas. The mono-, di-, tri- or polyurea component of this invention is a water and oil insoluble organic compound having a molecular weight between about 375 and 3,400 and having at least one ureido group and preferably between about 2 and 8 ureido groups. A ureido group as referred to herein is defined as /N--C--N

A p~ ulally preferred polyurea compound has an average between 3 and 4 ureido groups and has a molecular weight between about 600 and 1200.
In one rllllloll;l.. ,l, the mono-, di-, tri- or polyurea ~;n",l.o~ c are prepared 20 by reacting the following co,-.~.
I. A d;;.,o~ having the formula: OCN--R--NCO wherein R is a llyd~ lJyl~e having firom 2 to 30 carbons and preferably from 6 to 15 carbons and more preferably 7 carbons.

2183~1 1 g II. A polyamine having a total of 2 to 40 carbons and having the formula:
H~N--R1 ~N--R2 N ] ~N\JN~H
wherein Rl and R2 are the same or different type of ~lylluca~byl~ having from 1 to 30 carbons and preferably from 2 to 10 carbons and more preferably from 2 to 4 carbons;
R~ is selected from hydrogen or a Cl_CJ alkyl and preferably hydrogen;
x is an integer from û to 4;
o y is û or 1; and z is an integer equal to û when y is I and equal to I when y is û.
III. A ",."'r~ compound selected from the group consisting of u~,. having I to 30 carbons, preferably from 10 to 24 carbons, a ""~ having from I to 30 carbons preferably from lû to 24 carbons, and 5 mixtures thereof.
The reaction can be conducted by contacting the three reactants in a suitable reaction vessel at a It~ ,dlult: between about 60 to 320F (.16 to 169C), preferably from 100 to 300F (38 to 149C) for a period from 0.5 to 5 hours and preferably from 1 to 3 hours. The molar ratio of the reactants present usually varies from û. 1-2 20 moles of ~ P or monoisocyanate and 0-2 moles of polyamine for each mole of J;;Ju~"yallal~. When the l"" .~ is employed, the molar quantities are preferably (n + I) moles of d.i.,u~_ , (n) moles of diamine and 2 moles of ~ When the yalla~; is employed, the molar quantities are preferably (n) moles of diisocyanate, (n + I) moles of diamine and 2 moles of 25 ~llUllO;~

. 218381 1 A particularly preferred class of mono-, di-, tri- or polyurea ~ .,uu..d, has structures def ned by the following general formulae:
R3--NH [L~--NH--R4--NH--C r~'I Rb rJll~C--NH--R4--NH--C--N~R3 o o o o R3NH--C--NH--RsNH~C--NH--R4--NH--C--NH--R~ Nl I ] C--NH--R3 n R3--NH~C--NH--R4--NH--C--NH--R, Nl 1 ] C--NH--R3 o wherein:
n is an integer from 0 to 4;
R3 is the same or different llydluca~l/yl having from I to 30 carbon atoms, preferably from 10 to 24 carbons;
RJ is the same or different Iydlu~,a~ having from 2 to 30 carbon atoms, 5 preferably from 6 to 15 carbons; and R5 is the same or different ~.JJ.u~,al~ylene having from 1 to 30 carbon atoms, preferably from 2 to 10 carbons.
The llydlu~ " as defned in R, and R2above, is a divalent llydlu~,all)ù
radical which may be aliphatic, alicyclic, aromatic or ~... ,1,;,,-l;1,.,~ thereof, e.g., 20 alkylarylene, aralkylene, alkyl~,yl~ h,l.~" eyl~ ylalyL,Il~ etc., having its two free valences on different carbon atoms.
The mono-, di-, tri- or polyureas having the structure presented in Formula I
above are prepared by reacting (n + 1) moles of di;~u~,y~llat~, with two moles of a ù~ n; and (n) moles of a diamine. (When n equals zero in the above Formula 1, 21838~ 1 the diamine is deleted.) Mono-, di-, tri- or polyureas having the structure presented in Formula 2 above are prepared by reacting (n) moles of a ~ ,uuydlldlc with (n + 1) moles of a diamine and two moles of a IllUllu;Dv~,y_ (When n equals zero in the above Formula 2, the di;Dv~,yallaLc is deleted.) Mono-, di-, tri- or polyureas having 5 the structure presented in Formula 3 above are prepared by reacting (n) moles of a di;Do~,ya~ , with (n) moles of a diamine and one mole of a Illu~lv;i~u~y ' and one mole of a (When n equals zero in Formula 3, both the d;;Dv~y and diamine are deleted.) In preparing the above mono-, di-, tri- or polyureâs, the desired reactants 0 (d;;Dù~,yall~c, llullu;so~yall~e~ diamine and ~ ) are admixed within a suitable reaction vessel in the proper p. ul ul ~;UjlD. The reaction may proceed without the presence of a catalyst and is initiated by merely contacting the component reactants under conditions conducive for the reaction. The reaction itself is exothermic and, a.,~,u.d;l.gly, by initiating the reaction at room ~CIIIp~,ld~UI~, elevated 15 ~clll~,. d~UI ~;S are obtained. However, external heating or cooling may be desirable.
REACTANTS
The - or ~ullu;Svl,J used in the ~ nl- of the mono-, di-, tri- or polyurea will form the terminal end groups. These terminal end groups will ~ave from 1 to 30 carbon atoms, but are preferably from 5 to 28 carbons, and more 20 desirably from 6 to 25 carbon atoms.
Illustrative of various are p~ ' ?" h~,Ay' , I~ y' octylamine, decylamine, dOd~,ylalll;ll~, ICLI ade~yl , llw~ad~
ouladc~ylallull~ cicv~yl~ll;lle~ dodecenylamine, hexadc.,~,..ylaillilic, octad~ccl.yla.lul.~, o~t ~ yialll;ll~" al,;~ ià.ll;..." aniline, toluidene, 25 naphthylamine, .~Ull~rial~l;lle~ bornylamine, rellcllyla..l;l,c-, tertiary butyl aniline, b~l~ylalll;..~, beta-ph.,~.~,;ll.,~l....u,lc, etc. Palticularly preferred amines are prepared from natural fats and oils or fatty acids obtained therefrom. These starting materials can be reacted with ammonia to give first amides and then nitriles. The nitriles are then reduced to amines, cu.... ~y by catalytic llydlu~llaliu... Exemplary amines .
... . .. . . . . .. . . .

21 ~381 1 prepared by the method include O~ aUI~ ,y~ ' , oleylamine, p~ f~ lallll~ J~ , f l~oL~ ' , etc. The ~ed amines are particularly preferred.
Illustrative of ~f" . are heAylisocyanate, fJ~ ~li.,u~
5 dodJ~,yl;~cyanate, ~eLI~ld~ ;Aad~VYI;SU~Y ~ VC~
~,IO~ ~ , xyleneisocyanate, . ~ tyl;..u.,y ;y~.lool,ly~ .yf~ , etc.
The pf~l~. which form the internal llydlul,lLlboll bridges between the ureido groups usually contain from 2 to 4û carbons and preferably from 2 to 30 o carbon atoms, more preferably from 2 to 20 carbon atoms. Exemplary polyamines include diamines such as eth~l ~ ' e, I - U~ r- b~
flhflf~.. .I:- I:Ilf; O~'~i - f~ ; hf~Yr '-- --- "
ey. , Cyclooctr- ' p'~
~'~ ' , dianiline methane, flitf~l.l;.l",~.... Ih--~f~; bis(aniline), bis(toluidine), 5 piperazine, etc., triamines, such as aminoethyl piperazine, diethylene triamine, di~vlulJyl~.le triamine, N-methyl-diethylene triamine, etc., and higher polyamines such as triethylene tetramine, tetraethylene pentamine, pcntaethylene hexamine, etc.
R~i~-`u,~.l-~Liv~ examples of ~' ~. include l1~ J-d~ ;Ouf~yanate, o ~,; ' J ', ph.,..yl~ d;;~o"y 20 tolylenediisocyanate, bis(d;~ f ..yl;~ . ), methylene bis(pll~ llyl;su~ llaLe), etc.
~ nother preferred class of mono-, di-, tri- or polyurea cnnlro~lnr~e which may be OU.,~,~ sOrull~ employed in the practice of this invention include the following:
X~ NH--C--N~Y

21838~ 1 wherein:
n~ is an integer of 0 to 8, R~ is the same or different hydrocarbylene having from 2 to 30 carbon atoms, preferably from 6 to 15 carbons; X and Y are IIIVIIVV ' radicals selected from TABLE I below.
TABLE I
X Y
o /cl\ /c\
R8 N-- Rs N--Rs--\C \C
lo B o In the Table, R~ is the same or different ll~J~u~ J~ having from I to 30 5 carbon atoms, preferably from 2 to 10 carbons; Rg is the same or different l~yJlu.,~llbyl having from I to 30 carbon atoms, preferably from 10 to 24 carbons; R6 is selected from the group consisting of arylene radicals of 6 to 16 carbon atoms and alkylene groups of 2 to 30 carbon atoms, and R, is selected from the group consisting of alkyl radicals having from 10 to 30 carbon atoms and aryl radicals having from 6 20 to 16 carbon atoms.

-2t8381 1 Tolylene polyurea-thickened greases, wherein at least one R4, in the following formula, is tolylene are well known.
X~ NH--C--N~Y
By tolylene it is meant a divalent organic radical having its two free valences on 5 different carbon atoms of a ~ lhyl~ . moiety. For example, "2,4-tolylene"
refers to:
~H3 The mono-, di-, tri- or polyurea compounds are prepared by blending the several reactamts together in a suitable reaction vessel and heating them to a lo temperature ranging from 70F to 400F for a period sufticient to cause formation of the compound, generally from 5 minutes to I hour. The reactants can be added aU at once or se~
Examples of suitable d;;.~fJ~ lOllU;:lU~,yal~Lu;l~ J~ and polyamines are described supra.
The mono-, di-, tri- or polyurea f, ' are generally mixtures of ,nmr~ ' having structures wherein nl varies from 0 to 4, or nl varies from I to 3, existent within the grease ~ J ~;"" at the same time. For example, when a , a ~;;.,~,.,y and a diamine are f~oll.,ullcl~Lly present within the reaction zone, as in the preparation of mono-, di-, tri- or polyureas having the structure shown 20 in Formula 2, some of the mf - may react with both sides of the diisocyanate to form a diurea. In addition to the ru"""~ ", of diurea, ~ reactions can be occurring to form the tri', tetra,' penta', hexa', octa', etc., ureas. Particularly good results have been realized when the polyurea compound has an average of four ureido groups.

. ~ 21838~ 1 The amount of mono-, di-, tri- or polyurea compound in the final grease .n~ will be sufficient to thicken the base oil to the consistency of grease when combined with the alkaline earth metal ~,clbu~la~e. Generally, the amount of mono-, di,-tri- or polyurea will ran8e from 1 to 15 weight percent and preferably 5 from 2 to 7 weight percent of the final grease ~;n. ~ ~1 .n~ l ;.~..
The polyureas of the above formula are readily prepared by mixing diamines and .li;~ with rl.ol.oi,~,~ or I : in the proper p.~ iOl.~ to form the desired polyurea. The greases thickened with the polyureas are useful at Lt~ d~UI~,~ from about 100F to 500F. They are stable and remain oily after long o use, not becoming hard or brittle. The grease ~,~J~ r.~ thus formed are extremely resistant to ~ in water.
B. ANTIWF.~R AOVITTVES
As set forth below, the antiwear additives of the present invention are oil 5 soluble, neutral or overbased zinc ~,cl~u~yLt~
Zinc Hydrnrsrbyl cs~ yh~rp The zinc llyJl~ clbyl salicylate may be symbolized by the following formula:
- ~--O
R~OH Zn+

20 wherein R is a l~ owlbyl group containing from about 7 to about 40 carbon atoms.
The R group may be any lly~lu~,cl~yl group; however, alkyl groups cobtaining from 7 to 40 carbon atoms are preferred. Alkyl groups containing about 7 to about 24 carbon atoms are more preferred, and alkyl groups containing about 12 to about 18 carbon atoms are most preferred. The zinc salts may be neutral, and may be prepared 25 from neutral sodium llydlul,cll)yl salicylates by metal exchange. In this method of .. . .. ... ...

preparation, the sodium salicylate is treated with a zinc salt, such as zinc chloride, to give the desired zinc salt. In another method of preparation, an alkali metal phenate along with an excess of an alkali metal hydroxide is treated with carbon dioxide. The product is an overbased salicylate of up to 200 conversion ~hen tbis salt is treated s with zinc, an overbased zinc salicylate is produced.
Zinc F~tty A~ Carbsxyl~t~
The essential feature of the ~,al bu~yl4t~,s used in this invention is that they are oil-soluble. The zinc salts of short chain fatty acids, such as acetic, proprionic and butyric, are not sufdciently oil soluble to be usable in the compositions of the present o invention. The salts of fatty acids containing 8 or more carbon atoms provide the required degree of oil solubility. Specifc examples of usable fatty acids include caprylic acid (C8), capric acid (C1O), lauric acid (Cl2), myristic acid (C14), palmitic acid (C16), stearic acid ~CI8), o~eic acid (,.~ ,a~(l Cl8), ricinoleic acid ~12 hydroxy oleic acid) and linoleic acid (l 4~d Cl8). No particular fatty acid is required in the practice of the present invention. Any particular fatty acid may be included or execluded as desired. The zinc salts may be prepared by forming the sodium salt of the carboxylic acid, and reacting that salt with zinc cbloride. This l~la.,en~
reaction may be conducted at a , ~ between 100 and 200C. Zinc t~albu~ylal~ may also be prepared by ~ ",i~ )" of fats using zinc oxide. Zinc 20 ~4lbu~yla~ may also be prepared by the reaction of zinc oxide with carboxylic acids.
The reaction is conducted at a moderately elevated ~ u.c; to drive offthe water formed during the reaction. The moderately overbased zinc ~al~v~yl4l~ may be prepared by methods well known to those skilled in the art.
Zinc ~ ' Qf the Rr~ ~ Pro~ r~ of GlyoxYlic ~ri~ and Elvdrocarbyl Phenûls 2~8381 1 The zinc glyoxylates useful in the present invention are zinc salts of the reaction product of glyoxylic acid and hydrocarbyl substituted phenols. These zinc salts correspond to the following formula:
R OH
lr 1 H--f c_o ~
R OH
wherein Ar is an aromatic group containing 1 to 3 aromatic rings, R is one or more llydlu~,albll groups containing from about 4 to about 150 carbon atoms provided that the number of R groups shall not exceed the available valences on the aromatic group. rt is readily apparent from the formula that the zinc salts are the zinc salts of the bis (IyJlu~hb~l substituted hJ.llu~alyl) acetic acids produced in the reaction between the glyoxylic acid and the phenol. The phenols used to prepare these salts generaDy contain aromatic groups (Ar) having no substituents except for the R groups.
However, for reasons of cosS and availability, etc., Ar is normally a benzene nucleus.
5 Most preferably Ar is a benzene nucleus substituted by an R group in a position para to the OH group.
Preferably each R is an aliphatic group containing at least 4 and up to about 150 carbon atoms, frequently from about 4 to about 100 carbon atoms, preferably from about 4 to about 75 carbon atoms. In one ~ buJ;~ ,L, R contains about 4 to about 50 carbon 20 atoms, and in another ~..,1,~ ' from about 4 to about 24 carbon atoms, R is preferably alkyl or alkenyl, preferably ' '1~ saturated alkenyl. Each R may alsobe an aliphatic group containing about 7 to about 15û carbon atoms, or from about 7 to about 100 carbon atoms, or from about 7 to about 75 carbon atom$ or from about 7 to about 5û carbon atom$ or from about 7 to about 24 carbon atoms, or from about 12 to 25 about 24 carbon atoms. R is preferably aDcyl or alkenyl, preferably ~ saturated alkenyl. In one preferred r~ R contains at least 7 carbon atoms, of ren from 12 _, .. .. .... . . . _ ~ 218381 1 to 18 carbons. In another v~ , each R contains an average of at least 30 carbon atoms, of ~en an average of from about 30 to about l00 carbons. In another P~ u~R contains from 12 to about 50 carbon atoms. In a further v, "I ,o.li, ... ~, R contains from about 12 to about 24 carbon atoms and preferably from about 12 to about 18 carbon 5 atoms. For reasons of cost and availability, heptyl, octyl and ll~,.JI ~,L~u~c l phenols - 7 to 9) are a preferred ' - " for this appGcation.
The zinc ions may be derived from zinc metal or reactive zinc compounds that will react with carboxylic acids to form ~ bu~.~latc~ such as zinc oxide, zinc hydroxide, zinc carbonate, etc.
Thezincglyo%ylates(zincsaltsofthebis(ly-llu~ lsubstitutedlly-llu~alyl) acetic acids), which are usefiJI as antiwear agents in the greases of this invention, may be readily prepared by reacting (a) a reactant of the formula Rm-Ar-OH
5 wherein R is hydrocarbyl containing about 4 to about 150 carbon atoms, m ranges from l to about l0, Ar is an aromatic group containing l to 3 rings, and m does not exceed the avajlable valences of Ar after aUowing for at least one reaction site for the glyoxylic acid to react;
(b) glyoxylic acid shown below as the hydrate HO` R
C--C--OH
HO
Water of hydration as well as any water generated by the ~ reaction is preferably rernoved during the course ofthe reaction.
The reaction is normaUy conducted in the presence of a strong acid catalyst.
Particularly useful catalysts are iUustrated by ' '~ acid arld para-25 ~ i acid. The reaction is usuaUy conducted with the removal of water.
Reactants (a) and (b) are preferably present in a molar ratio of about 2:1;
however, useful products may be obtained by employing an excess amount of either 2~838~ ~
, -reactant. Thus, molar ratios of (a):(b) of 1:1, 2:1, 1:2, 3:1, etc. are, . ' ' and useful products may be obtained thereby. Illustrative examples of reactants (a) include hydroAYy aromatic compounds such as phenols, both substituted and I ' ' within the constraints imposed on Ar hereinabove, and a variety of aromatic hydroAYy 5 rl~mpclJntlc ~n all the above cases, the aromatic groups bearing the phenotc -OHgroups may be singfe ring, fused ring or linked aromatic groups as described in greater detail hereinabove.
Specific iUustrative examples of compounds which may be employed as reactant (a) llydlu~ulrsubstituted phenols such as di-allcyl phenols, naphthol, 2,2'-~ Y~II UA Y~ I.J 1, 4,4 , ll UA YI . J ~ 3 t., ~11 u~ ,- ., I ,2, 1 0 _ 1, resorcinol, 2-t-butyl pheno~ 4-t-butyl phenol, 2,6-di-t-butyl phenol, 2,4-di-t-butyl phenol, octyl phenol, cresols, di-nonyl phenol, propylene tetramer-substituted phenol, propylene oligomer (Mw 300-800)-substituted phenol, polybutene (number average Mw about 1000)-substituted phenol, substituted-naphthols ~;ull~ul~d~ to the above eAYemptified phenols, methyleneAbis-phenol, bis-(1 t.,lluA.~t.~ ')-2,2-propane, and Iydlu~,~lJull-substituted bis-phenols wherein the tlJdluwl~ul~ substituents have at leAAst 4 carbon atoms, for example, butyL pentyl, he,Yyl, octyl, dodecvl, oleyl, polybutenyl.
The method of preparation of numerous alkyl phenols is well known. lllustrative examples of allcyl phenols and related aromatic compounds and methods for prepanng same are given in U.S. Patent 4,740,321 to l~avis et a~. This patent is hereby herein by reference.
U.S. Patents 2,933,520 (13ader) and 3,954808 (Elliott et al) describe procedure~c for preparing the reaction product of a phenol and glyoxylic acid. These patents are expressly referred to herein for relevant disclosures relating to preparative procedures and methods contained therein.
The " product obtained from the reaction of the foregoing hydroxy romatic compounds and carboxylic acids is then reacted with a metal contaGling reAActant to form a salt. Suitable metal-cont ining reactants have been enumerated 1~ uve.

2~8381 ~

The above examples are intended to be illustrative of suitable reactants amd arenot mtended, and should not be viewed as, an exhaustive hsting thereof.
The carboxylate salt is formed by reaction of the metal containing reactant withthe glyoxylic acid derivative. Tbe preparadon of these salts is described in U.S. Patent 5,356,546.
The Zinc salts are effective as antiwedr agents at a level from .01% to about 10%
by weight of the final grease ~ The preferred amount of the antiwear zinc salt additive is from about 0.25% to about 1%.
Preparation of ~`Tr~c~-c 0 The methods of preparing urea grease thickeners are well known to those skilled in the art. In a typical preparation, grease . . may be prepared starting with a base oil of lubricating viscosity and the reactants needed to form an urea thickener. For example, mixture of an amine and the oil is warmed, and the a~ lu~ isocyanate or mixture ûf isocyanates added. Optionally, the isocyanate may be added as an oil solution. The reaction between the amines and the isuc~ ld~u~ proceeds rather rapidly and generates some heat which is controlled by how much hedt is applied to the kettle and the rate of addition of isocyanate.
Generally, the reaction between the amines and the iSu~alla~c~ is conducted at aLc~ .d~ul~ between about 30 and 70 C. A~er the urea thickener is formed, a small arnount of water is added, and the grease is cooked at a Lc~p~"dLu~c up to about210 C. The water reacts with any residual duDu~laLc. The grease is then cooled,and other desirable additives may be added along with further base oil, if desired. The grease is then milled using an d~ I ' grease mill to produce the f nal product. If desired, further additives may be added by reheating the grease and remilling toi--~,ul~.o,~lL~ these further additives. Variations on this basic process for the formation of urea-thickened greases will be readily apparent to those skilled in the art.
Method of T ~
The ~reases of the present invention may be readily used as lubricants to lubricate metal objects which are in motion relative to one another. In the practice of this method, , .. . ........ ...... . ..

21838~ ~

the grease of the present invention is placed between the metal objects and provides lubrication and thereby reducing the friction between the metal surfaces as they move with respect to each other. The Lubricant action is provided by the oil of lubricating viscosity.
The zinc salts described above, further reduce the friction between the metal surfaces.
The urea-thickener serves to thicken the entire . so that it remains between themetal surfaces rather than fiowing out. The amount of grease to be used in this method is determined by the geomet~y of the metal surfaces to be lubricated. Thus, for example, if the grease is to be used in an automotive roller bearing assembly, the avaGable space in the bearing assembly is packed with grease.
o AD patents referred to herein are expressly i"c."~u~ d by reference for their relevant disclosures.
The following specific illustrative Examples describe the preparation of the compounds of Formula (~ useful in the r~ ,r.~ of this invention. In the following examples, as well as in the claims and in the ~ of this appGcation, parts are s ~arts by weight, the Itlll~aLul~ is degrees Celsius and the pressure is ~ l l ""~,h .. ., unless otherwise indicated.
As will be readily apparent to those skilled in the art, variations of each of the iUustrated reactants and cl " "l, - - ~ of reactants and condGtions may be used. E~Al~ F~
FY~~i~ A
Preparation of 7:in~
800 parts of diluent oil were added to a reactor. 180.8 parts of zinc chloride were added with stirring. 200 parts of water was added. The mixture was warmed to a temperature of 90 - 93C over one hour. 1000 parts of the sodium salt of an~'~yl~ali~,ylaLe (contairling Yylene 65 to 75% sodium alkyl salicylate); in which the alkyl group contains between 14 and 18 carbons, was added at a i , ~ of 91-96 C. The batch was held for 2 hours at this t.,..~ ldLult. The batch was heated to 154-160, for a period of 6 hours, while nitrogen was bubbled through the batch to remove aqueous and organic materials. Finally the batch was vacuum-stripped at a 21838~ ~

~tlll~J~I d~UI ~; of 154-160~ C and a pressure of 20 millimeters of mercury. The product was filtered and the filter flushed using ~ 577 parts of diluent oil.
Slightly more or less diluent oil may be used to adjust the product to the desired final COilC~ iOll. The final water content was less than 0.30%. The product contained 30% of the zinc salicylate, and 70% diluent oil.

A polyurea grease was prepared by reacting 4,4'-methylene biphenyl . ~ with a commercial grade of tall oil amine containing ~
palmityl amine, stearyl amine, and oleyl amine. The amine and the isocyanate were 0 reacted in the base oil at ~~ J~llla~ 200C. The thickened oil was mixed in a grease mill, and the resulting thickened polyurea grease was set aside as a base stock for use in preparing grease samples.
Six grease r~ nl,~ were prepared starting with a base grease thickened with an urea tbickener (results shown in TABLE 1). The greases were subjected topenetration tests and dropping point tests. In addition, they were subjected to the four-ball wear test to determine a scar diameter, as well as the coefficient of fiiction.
Samples 1 through 5 are not examples of the present invention, but instead were prepared with commonly used grease additives. Samples 1-5 are presented for comparison purposes. Sample 6 was prepared according to the present invention.
Sample I consisted of the base grease mixed with 1% of an additive formed by reacting C14 1g-alcohols with P2Os followed by salting with alkyl C12 14 primary arnines. Sample 2 was formed by addirlg to the base grease 1% of an additive comprising 76.5% of an amine salt of .I;~luo, ' , ' - acid, 17.5% of d;bu~ o~ll;l~, and 6% diluent oil. Sample 3 was formed by addirlg to the base oil 1% of an additive consisting of a calcium overbased sulfonate (TBN = 375) and 50%
diluent oil. Sample 4 was formed by adding to the base grease 1% of the additive of Sample 2 and 1% of the additive of Sample 3. Sample 5 was prepared by adding to the base 1% of an additive containing 85% borated soybean lecithin and 15% oil.
Sample 6 was prepared by adding to the base grease 1% of an additive, prepared in ., _ . .. .. _ . . . .

2~8381 1 Example A, consisting of 30% of the neutral zinc salt of a C14 1g alkyl salicylic acid and 70% diluent oil.
TABLE~ I
Dropping Four-ballWear Penetration Point ASTM D2266 Sample ID 13NW 60X IOK C Scar, mrn CoefE of Friction Polyurea 299 301 306 209 .55 .0907 base grease Example I
315 310 321 206 .39 .0335 2 304 303 300 203 .44 .0385 3 309 308 319 209 .44 .0400 4 313 306 317 203 .47 .0465 5 315 312 311 208 .39 .0360 6 316 311 321 206 .36 .0285 ~NW is the results for the unworked grease.
60X is the results for each grease after 60 strokes.
IOK is the results after 10,000 strokes.

Further grease samples were prepared by addir~g zinc oleate as an antiwear agent to a commercial sample of a polyurea grease base. The commercial grease base contained a polyurea thickener similar to that prepared in EXAMPLE 1. The base grease served as a control in the tests of the grease. Grease sample 7 was prepared by adding 2 percent zinc oleate to the base grease. Grease sample 8 was prepared by adding I percent zinc oleate to the base grease. Grease sample was prepared by .

~ 21 8381 1 adding 0.5 percent zinc oleate to the base grease. These samples were tested using the a four-ball wear test like that used for EXAMPLEi 1. The four-ball wear test was used to determine the coefficient of friction and the scar diameter. The results are shown in TABLE 2. Because the four-ball wear tests were perfortned at different times, the results are . ' '~ to each other, but not to the results of EXAMPLE
1.
TABLl~ 2 % WT
Polyurea Base Grease 100 % 98 % 99 % 99.5 %
Zinc Oleate 2% 1% 0.5 %

Four-ball Wear Hours l l l I
Temp, F 167 167 , 167 167 Weight 40 Kg 40 Kg 40 Kg 40 Kg Avg. Coeff. of Fric. 0.076/0.0900 0.098/0.091 0.06/0.062 0.057/0.058 ~vg. ScarD;~ t~./,u.. 0.81/0.84 0.57/0.54 0.48/0.51 0.6/0.48 r A zinc glyoxylate (zinc salt of a bis (llyJIul,alb~l substituted ll/JIu~alyl) acetic acid) was prepared by reacting 2 moles of dinonyl phenol with I mole of glyoxylic acid hydrate in the presence of catalytic quantities of methane sulphonic acid(O.19%byweight). ThemixturewasvacuumstrippedatllOCand35mm.Hg to remove water. The product was neutralized with potassium hydroxide. The resulting potassium salt was reacted with a ~ ' amount of zinc chloride to form the zinc glyoxylate. The product contains 60 % neutral zinc glyoxylate, and 40 % diluent oil.

EXAMPI~ 4 A further grease sample was prepared by adding the zinc glyoxylate (zinc salt of the bis (l~ u~,al~yl substituted ~I~IIu~alyl) acetic acid) of EXAMPLE B as anantiwear agent to a cornmercial sample of a polyurea grease base. The ~ ~;al grease base contained a polyurea thickener similar to that prepared in EXAMPLE 1.
The base grease served as a control in the tests of the grease. Grease sample 10 was prepared by adding 0.6~ percent of the zinc glyoxylate of EXAMl?LE 3 (containing0.4 % zinc glyoxylate) to the base grease. The four-ball wear test was used to determine the coefficient of friction and the scar diameter. The results are shown in TABLE 3. Because the four-ball wear tests were performed at different times, the 218381 i results are ~ to each other, but not to the results of EXAMPLE 1.
TABI,E 3 % WT
Polyu}ea Base Grease 100 % 99.33 %
Zinc Glyoxylate (Ex. 3) 0.67%

Four-ball Wear ~ours Temp, F 167 167 Weight 40 Kg 40 Kg Avg. Coeff. of Friction 0.07610.0900 0.065 Avg. ScarD;~ .,t~,./l.. l. 0.8110.84 0.48

Claims

1. A grease composition comprising (A) a major amount of an oil of lubricating viscosity, (B) a thickener selected from the group consisting of monoureas, diureas, triureas and polyureas, or mixtures thereof, and (C) an oil-soluble neutral or overbased zinc salt of a carboxylic acid selected from the group consisting of zinc salts of fatty acids, the zinc salts of hydrocarbyl-substituted salicylic acids, and zinc glyoxylates, provided that if (c) is the zinc salt of a fatty acid, the fatty acid is not ricinoleic acid.

2. A grease composition according to claim 1 wherein the oil-soluble zinc salt comprises an overbased zinc salt.

3. A grease composition according to claim 1 wherein the oil-soluble zinc salt comprises a zinc salt of a hydrocarbyl-substituted salicylic acid corresponding to the following formula:
Zn+2 wherein R is a hydrocarbyl group.

4. A grease composition according to claim 3 wherein the oil-soluble zinc salt comprises an overbased zinc salt of a hydrocarbyl-substituted salicylic acid.

5. A grease composition according to claim 3 wherein the R group contains between about 7 and about 40 carbon atoms.

6. A grease composition according to claim 3 wherein the R group contains between about 7 and about 24 carbon atoms.

7. A grease composition according to claim 3 wherein the R group contains between about 12 and about 18 carbon atoms.

8 A grease composition according to claim 1 wherein the oil soluble zinc salt comprises a zinc salt of a fatty acid.

9. A grease composition according to claim 8 wherein the oil soluble zinc salt is selected from group consisting of the zinc salts of caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, and linoleic acid.

10. A grease composition according to claim 8 wherein the oil soluble zinc salt is the zinc salt of oleic acid.

11. A grease composition according to claim 10 wherein the oil soluble zinc salt is an overbased zinc salt of oleic acid.

12. A grease composition according to claim 1 wherein the oil soluble zinc salt comprises a zinc glyoxylate of the following formula:
Zn++
wherein Ar is an aromatic group containing 1 to 3 aromatic rings, R is one or more hydrocarbyl groups containing from about 4 to about 150 carbon atoms provided that the number of R groups shall not exceed the available valences on the aromatic group.

13. A grease composition according to claim 12 wherein R contains about 4 to about 100 carbon atoms.

14. A grease composition according to claim 12 wherein R contains about 4 to about 50 carbon atoms.

15. A grease composition according to claim 12 wherein R contains about 4 to about 24 carbon atoms.

16. A grease composition according to claim 12 wherein R contains about 7 to about 100 carbon atoms.

17. A grease composition according to claim 12 wherein R contains about 7 to about 50 carbon atoms

18. A grease composition according to claim 12 wherein R contains about 7 to about 24 carbon atoms.

19. A grease composition according to claim 12 wherein R contains about 12 to about 18 carbons atoms.

20. A grease composition according to claim 1 wherein the thickener comprises a monourea.

21. A grease composition according to claim 1 wherein the thickener comprises a diurea.

22. A grease composition according to claim 1 wherein the thickener comprises a triurea.

23. A grease composition according to claim 1 wherein the thickener comprises a polyurea.

24. A method of lubricating metal surfaces which move with respect to each other which comprises placing between said metal surfaces an appropriate quantity of a grease composition comprising of a major amount of an oil of lubricating viscosity, a thickener selected from the group consisting of monoureas, diureas, triureas and polyureas, or mixtures thereof, and an oil-soluble neutral or overbased zinc salt of a carboxylic acid selected from the group consisting of zinc salts of fatty acids, the zinc salts of hydrocarbyl-substituted salicylic acids, and zinc glyoxylates.

25. A method according to Claim 24, wherein C is the zinc salt of ricinoleic acid.