Note: Descriptions are shown in the official language in which they were submitted.
21~3811
2698R-01
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
--2--
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
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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-
218381 1
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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
R2
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 ~
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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 ~
-7-
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.
. ... . .. ..... .. . . ... . ..
2 1 8381 1
- 8 -
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
- 10-
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
FORMULA 1
o o o o
R3NH--C--NH--RsNH~C--NH--R4--NH--C--NH--R~ Nl I ] C--NH--R3
n
FORMULA 2
R3--NH~C--NH--R4--NH--C--NH--R, Nl 1 ] C--NH--R3
FORMULA 3
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
- 11
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
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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
- 13 -
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
R7 8--NH-- R7 C--NH--R5
/cl\ /c\
R8 N-- Rs N--Rs--
\C \C
lo B o
R8--
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
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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
- 15-
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+
-- 2
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
.. . .. ... ...
218381 1
- 16-
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
- 17 -
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
- 18
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~ ~
, -
- 19 -
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 ~
-20 -
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~ ~
-21 -
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~ ~
-22 -
~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.
EXAMPLE 1
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
-23 -
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.
EXAMPLE 2
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
-24 -
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 %
ASTM D2266
Four-ball Wear
Hours l l l I
Temp, F 167 167 , 167 167
RPM1200 1200 1200 1200
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
218381 1
-25 -
EXAMPLE 3
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
-26-
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%
ASTM D2266
Four-ball Wear
~ours
Temp, F 167 167
RPM 1200 1200
Weight 40 Kg 40 Kg
Avg. Coeff. of Friction 0.07610.0900 0.065
Avg. ScarD;~ .,t~,./l.. l. 0.8110.84 0.48
