METHOD OF AND COMPOSITIONS FOR REDUCING WEAR ON SURFACES SUBJECTED TO FRICTIONAL FORCES

METHODE ET LUBRIFIANT POUR REDUIRE L'USURE DES SURFACES DE FROTTEMENT

English Abstract

A method and composition for reducing wear on
surfaces subjected to frictional forces. The
lubricating compositions can be applied in a carrier
which may be organic or inorganic in nature. They
function by providing a regime in which multimolecular
layers are adsorbed onto the surfaces to be protected,
thus enabling comparatively thick protective films to
be built up on the surfaces subjected to fractional
wear.
The molecules having the property are essentially
single or condensed unsaturated ring systems which
comprise at least one six-membered unsaturated
heterocyclic ring comprising at least one heterocyclic
moiety which acts as a hydrogen acceptor and a
hydrogen donor moiety. If substituents are present
they should not create steric hindrance and/or render
the molecule so basic or acidic as to alter the steric
geometry of the molecule as to prevent the interaction
of the active groups.

Claims

-20-
THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A composition of matter for providing a lubricating
regime in which adherent multimolecular layers of a heteropolar
material are absorbed onto a surface to be protected from
frictional wear, said composition of matter comprising:
a carrier for a heteropolar material; and
an amount of a heteropolar material in said carrier
effective to produce a multimolecular lubricating layer of the
heteropolar material having anti-surface wear properties on a
surface to be protected from frictional wear when said composition
is brought into contact with such surface, said heteropolar
material comprising a heteropolar compound having at least one
wholly unsaturated heterocyclic six-membered ring in which at least
one unsubstituted heteroatom moiety acts as a hydrogen acceptor and
in which said compound also comprises at least one hydrogen donor
moiety and in which said heteropolar compound has no substituent
which by itself or together with another substituent or
substituents creates such steric hinderance and/or renders the
molecule so basic or acidic so as to alter a steric geometry of the
molecule as to prevent interaction of the hydrogen donor and
acceptor moieties of one molecule of the heteropolar compound with
the hydrogen donor and acceptor moieties of another molecule of the
heteropolar compound nor any substituent or substituents has the
effect of solubilizing said heteropolar compound in the selected
carrier to the extent that migration of the heteropolar compound to
the interfaces of the carrier with the carrier environment is
prevented,

- 21-
said effective amount of said heteropolar material being
heteropolar material in the composition which is available to
migrate to the interfaces of the carrier with the carrier
environment, and said effective amount being an amount of at least
0.5% by weight based on the total weight of carrier and heteropolar
material.
2. A composition as claimed in claim 1, in which the
heteropolar compound comprises up to three condensed unsaturated
rings, one of which rings is said wholly unsaturated heterocyclic
six-membered ring.
3. A composition as claimed in claim 2, in which one of said
condensed rings is a five-membered unsaturated heterocyclic ring.
4. A composition as claimed in claim 2, in which all the
condensed rings are six-membered unsaturated rings.
5. A composition as claimed in claim 1, in which the
carrier is a liquid.
6. A composition as claimed in claim 5, in which the liquid
is a lubricating oil.
7. A composition as claimed in claim 5, in which the liquid
comprises at least one unsaturated hydrocarbon.
8. A composition as claimed in claim 5, wherein the
heteropolar compound is present in the range of from 0.5 to 4% by
weight based on the total weight of carrier and additive.
9. A composition as claimed in claim 5, in which the carrier
is an aqueous liquid.
10. A composition as claimed in claim 5, in which the carrier
is a liquid hydrocarbon fuel for an internal combustion engine.

- 22 -
11. A composition as claimed in claim 1, in which the
carrier is a lubricating grease or grease-like material.
12. A composition as claimed in claim 11, wherein the
heteropolar compound is present in the range 3% to 10% by weight
based on the total weight of carrier and additive.
13. A composition of matter for providing a lubricating
regime in which adherent multimolecular layers of a heteropolar
material are absorbed onto a surface to be protected from
frictional wear, said composition of matter comprising:
a solid plastic material carrier for a heteropolar
material; and
an amount of a heteropolar material in said carrier
effective to produce a multimolecular lubricating layer of the
heteropolar material having anti-surface wear properties on a
surface to be protected from frictional wear when said composition
is brought into contact with such surface, said heteropolar
material comprising a heteropolar compound having at least one
wholly unsaturated heterocyclic six-membered ring in which at least
one unsubstituted heteroatom moiety acts as a hydrogen acceptor and
in which said compound also comprises at least one hydrogen donor
moiety and in which said heteropolar compound has no substituent
which by itself or together with another substituent or
substituents creates such steric hinderance and/or renders the
molecule so basic or acidic so as to alter a steric geometry of the
molecule as to prevent interaction of the hydrogen donor and
acceptor moieties of one molecule of the heteropolar compound with

- 23 -
the hydrogen donor and acceptor moieties of another molecule of the
heteropolar compound nor any substituent or substituents has the
effect of solubilizing said heteropolar compound in the selected
carrier to the extent that migration of the heteropolar compound to
the interfaces of the carrier with the carrier environment is
prevented.
14. A composition as claimed in claim 13, in which the solid
plastics material is a polyamide.
15. A composition as claimed in claim 13, wherein the
heteropolar compound is present in the range 10.1% to 20% base don
the total weight of carrier and additive.
16. A composition as claimed in claim 1, in which the
heterocyclic moiety which acts as a hydrogen acceptor is an -N=
moiety.
17. A composition as claimed in claim 16, in which the
heteropolar compound contains up to four -N= moieties.
18. A composition as claimed in claim 1, in which the
hydrogen donor moiety is an -OH group.
19. A composition as claimed in claim 1, in which the
heteropolar compound is 8-hyadroxyquinoline.
20. A composition as claimed in claim 1, in which the
heteropolar compound is selected from 2,3-dihydroxypyridine, 4,6-
dihydroxypyrinidine, 2-pteridinol, 2-methyl 8-quinolinol, 2,4-
quinolindiol, 2,3-dihydroxyquinoxalin, 2,4-pteridinediol, 6-
purinol, 3-phenanthridinol, 2-phenanthrolinol and 2-phenazinol.

- 24 -
21. A lubricated article comprising:
a solid article having a surface to be protected from 2-
body or adhesive wear; and
a lubricating regime on said surface in which an adherent
multimolecular lubricating layer of a heteropolar material having
anti-surface wear properties is absorbed onto the surface, said
heteropolar material comprising a heteropolar compound having at
least one wholly unsaturated heterocyclic six-membered ring in
which at least one unsubstituted heteroatom moiety acts as a
hydrogen acceptor and in which said compound also comprises at
least one hydrogen donor moiety and in which said heteropolar
compound has no substituent which by itself or together with
another substituent or substituents creates such steric hinderance
and/or renders the molecule so basic or acidic so as to alter a
steric geometry of the molecule as to prevent interaction of the
hydrogen donor and acceptor moieties of one molecule of the
heteropolar compound with the hydrogen donor and acceptor moieties
of another molecule of the heteropolar compound nor any substituent
or substituents has the effect of solubilizing said heteropolar
compound in a selected carrier therefor to the extent that
migration of the heteropolar compound to the interfaces of the
carrier with the carrier environment is prevented,

said heteropolar material being present in an effective
amount, which effective amount is that amount which is available in
the lubricated article for migration to the surface to be protected
and is an amount of at least 0.5% by weight based on the total
weight of carrier present and heteropolar material.
22. A method for reducing 2-body or adhesive wear on a
surface which is subject to such wear by establishing on said
surface a lubricating regime in which an adherent multimolecular
layer of a heteropolar material having anti-surface wear properties
is absorbed onto the surface, said method comprising the steps of:
adding said heteropolar compound to a carrier through
which the heteropolar compound can migrate, said heteropolar
compound being present in the carrier in an amount effective to
produce said adherent layer on said surface when brought into
contact therewith, said heteropolar material comprising a
heteropolar compound having at least one unsaturated heterocyclic
six-membered ring in which at least one unsubstituted heteroatom
moiety acts as a hydrogen acceptor and in which said compound also
comprises at least one hydrogen donor moiety and in which said
heteropolar compound has no substituent which by itself or together
with another substituent or substituents creates such steric
hinderance and/or renders the molecule so basic or acidic so as to
alter the steric geometry of the molecule as to prevent interaction
of the hydrogen donor and acceptor moieties of one molecule of the
heteropolar compound with the hydrogen donor and acceptor moieties
of another molecule of the heteropolar compound nor any substituent

- 26 -
or substituents has the effect of solubilizing said heteropolar
compound in said carrier to the extent that migration of the
heteropolar compound to the interfaces of the carrier with the
carrier environment is prevented,
said effective amount of said heteropolar material being
heteropolar material in the composition which is available to
migrate to the interfaces of the carrier with the carrier
environment, and said effective amount being an amount of at least
0.5% by weight based on the total weight of carrier and heteropolar
material; and
bringing said carrier and said heteropolar compound into
contact with at least a portion of said surface for a time
sufficient to allow said compound to migrate onto the surface and
form said layer.
23. A method as set forth in claim 22, wherein said bringing
step includes causing said composition to contact said surface
continuously.
24 A method as set forth in claim 22, wherein said bringing
step includes causing said composition to contact said surface
intermittently.
25. A method of reducing 2-body or adhesive wear on
contacting surface which in relative motion are subject to adhesive
wear by applying a multimolecular lubricating layer onto at least
one of said contacting surfaces.

- 27 -
26. A method as claimed in claim 25 in which the
multimolecular lubricating layer is formed in situ on at least one
of said contacting surfaces by applying a lubricating compound to
said contacting surface via a carrier.
27. A method as claimed in claim 26 in which the lubricating
compound is a heteropolar compound.
28. A method as claimed in claim 26 in which the lubricating
compound is a heteropolar compound comprising at least one wholly
unsaturated heterocyclic six-membered ring in which at least one
unsubstituted heteroatom moiety acts as a hydrogen acceptor and
said compound further comprises at least one hydrogen donor moiety.
29. A composition as claimed in claim 1, wherein said layer
has a thickness in the range of from 1x10-9m to 1x10-6m.
30. A article as claimed in claim 21, wherein said layer has
a thickness in the range of from 1x10-9m to 1x10-6m.
31. A method as claimed in claim 22, wherein said layer has
a thickness in the range of from 1x10-9m to 1x10-6m.
32. A method for lubrication of contacting surfaces which are
subject to 2-body or adhesive wear comprising applying between said
surfaces a lubricating quantity of a heteropolar compound having at
least one wholly unsaturated heterocyclic six-membered ring in
which at least one unsubstituted heteroatom moiety acts as a
hydrogen acceptor and in which said compound also comprises at
least one hydrogen donor moiety and in which said heteropolar
compound has no substituent which by itself or together with

- 28 -
another substituent or substituents creates such steric hinderance
and/or renders the molecule so basic or acidic so as to alter a
steric geometry of the molecule as to prevent interaction of the
hydrogen donor and acceptor moieties of one molecule of the
heteropolar compound with the hydrogen donor and acceptor moieties
of another molecule of the heteropolar compound nor any substituent
or substituents has the effect of solubilizing said heteropolar
compound in the selected carrier to the extent that migration of
the heteropolar compound to the interfaces of the carrier with the
carrier environment is prevented.
33. A lubricated article comprising a surface to be protected
against 2-body or adhesive wear and a lubricating regime at said
surface providing an adherent layer of a heteropolar material for
protecting said surface against such wear.
34. A lubricated article as claimed in claim 33, in which
said lubricating layer has a thickness of 1x10-9m to about 1x10-6m.
35. A method of reducing 2-body or adhesive wear on a surface
which is subject to such wear by establishing on said surface a
lubricating regime in which an adherent multimolecular lubricating
layer of a heteropolar material is absorbed onto the surface, said
method comprising the steps of:

- 29 -
adding said heteropolar compound to a carrier through
which the heteropolar compound can migrate, and bringing said
carrier and heteropolar compound into contact with a portion of
said surface to be treated for a time sufficient to allow said
heteropolar compound to migrate onto said surface and form a
protective multimolecular lubricating layer thereon.

- 30 -
36. A method of reducing wear on a surface which is
subject to frictional forces which comprises forming
and maintaining on said surface a protective layer
characterised in that said protective layer is a
multi-molecular layer of a heteropolar compound
comprising at least one wholly unsaturated
heterocyclic six-membered ring in which at least one
unsubstituted heteroatom moiety acts as a hydrogen
acceptor and in which said compound also comprises at
least one hydrogen donor moiety, and in which said
heteropolar compound has no substituent which by
itself or together with another substituent or
substituents creates such steric hindrance and/or
renders the molecule so basic or acidic or so alters
the steric geometry of the molecule as to prevent
interaction of the hydrogen donor and acceptor
moieties of one molecule of the heteropolar compound
with the hydrogen donor and acceptor moieties of
another molecule of said heteropolar compound nor any
substituent which by itself or together with another
substituent or substituents has the effect of
solubilizing said heteropolar compound in a selected
carrier to the extent that migration of the
heteropolar compound to the interfaces of the carrier
with the carrier environment is prevented and in which

31 -
the protective layer is formed on the surface to be
protected by contacting at least a portion of the said
surface with a composition comprising a carrier and
dissolved and/or dispersed therein an effective amount
of said heteropolar compound.
37. A method as claimed in claim 36, in which at
least a portion of the surface to be protected is
continuously contacted with said composition.
38. A method as claimed in claim 36, in which at
least a portion of the surface to be protected in
intermittently contacted with said composition.
39. A method as claimed in any one of claims 36 to 38,
characterised in that the heteropolar compound
comprises up to three condensed unsaturated rings, one
of which rings is said wholly unsaturated heterocyclic
six-membered ring.
40. A method as claimed in claim 39, characterised
in that one of said condensed rings is a five-membered
unsaturated heterocyclic ring.
41. A method as claimed in claim 39, characterised
in that all the condensed rings are six-membered
unsaturated rings.
42. A method as claimed in any one of claims 36 to 38,
in which the carrier is a liquid.
43. A method as claimed in claim 42, characterised
in that the liquid is a lubricating oil.

- 32 -
44. A method as claimed in claim 43, characterised
in that the lubricating oil comprises at least one
unsaturated hydrocarbon.
45. A method as claimed in claim 44, characterised
in that the heteropolar compound is present in the
range 1.1% to 4% by weight based on the total weight
of carrier and additive.
46. A method as claimed in claim 42, characterised
in that the carrier is an aqueous liquid.
47. A method as claimed in claim 42, characterised
in that the carrier is a liquid hydrocarbon fuel for
an internal combustion engine.
48. A method as claimed in any one of claims 36 to 38,
characterised in that the carrier is a lubricating
grease or grease-like material.
49. A method as claimed in claim 48,
characterised in that the heteropolar compound is
present in the range 3% to 10% by weight based on the
total weight of carrier and additive.
50. A method as claimed in any one of claims 36 to 38,
characterised in that the carrier is a solid plastics
material.
51. A method as claimed in claim 50,
characterised in that the solid plastics material is a
polyamide.

- 33 -
52. A method as claimed in claim 51,
characterised in that the heteropolar compound is
present in the range 10.1% to 20% based on the total
weight of carrier and additive.
53. A method as claimed in any one of claims 36 to 38,
40, 41, 43, 44 to 47, 49, 51 and 52 characterised in that the heterocyclic
moiety which acts as a hydrogen acceptor is an -N= moiety.
54. A method as claimed in claim 53,
characterised in that the heteropolar compound
contains up to four -N= moieties.
55. A method as claimed in any one of claims 36 to 38,
40, 41, 43, 44 to 47, 49, 51, 52 and 54, characterised in that the hydrogen
donor moiety is an -OH group.
56. A method as claimed in any one of claims 36 to 38,
40, 41, 43, 44 to 47, 49, 51, 52 and 54, characterised in that the
heteropolar compound is 8-hydroxyquinoline.
57. A method as claimed in any one of claims 36 to 38,
40, 41, 43, 44 to 47, 49, 51, 52 and 54, characterised in that the heteropolar
compound is selected from 2,3-dihydroxypyridine,
4,6-dihydroxypyrinidine, 2-pteridinol, 2-methyl
8-quinolinol, 2,4-quinolindiol,
2,3-dihydroxyquinoxalin, 2,4-pteridinediol, 6-purinol,
3-phenanthridinol, 2-phenanthrolinol and 2-phenazinol.

Description

-1- 1 337292
DESCI~PT~ON
"METHOD OF AN~ CO~IPOSITIONS ~OR ~EDUC ING WEAR ON
SURFACES SUBJE~TED TO FRICTIONAL ~ORCES"
The present invention relate~ to a method of, and
~o~po6ieions for, redu~ing wear on s~rface~ ~ub~ected
to f~iction~l forces, p~r~ieulsrly ~etween mo~ng
surfaces.
The prim~ry purpo~e of lubrieation is separat~on
of moving surfRces to mln~m1se friction and wear.
Se~eral dist~nct regime~ are commonly reco~nised in
the field of lubr~ca~ion, Thus in fluid film
lubrication the load is ~upported entlrely by
pressures within the separ~e~ng fluid f~lm. This film
preCsure is frequen~ly gener~ted by relat~ve motion of
~e ~urfaces involved J which pumps the lubricant lnto
a con~ergln~. wedge-shaped ~one. The hydro dynamic
beha~iour of such bearings i8 completely dependene on
~e viscou~ behaviour of the lubricant. Bo~h the
load-~upporting o$1 fllm pres~ure and the power 1088
~re fun~tions of lubric~nt v1sco~ity ln combination
with the geometry and she~r r~te imposed by the
bear~ng opersting eonditlon~.
A~ the ~evé~ity of opera~lng condltlons lncrea~es,
a po~nt $~ e~entu~lly reached where the load c~n no
longer be c~rried completely by o~l-film ~upport.
High spots, or a~per~tles of the matinB ~urf~ces must

1 337292
-2 -
t~ en shear with the lubtic~nt in lo~d ~upport ~nd the
l~br~caeion reglme shifts from full-film eo mixed-fil~
and then to complete boundary high load, low speed,
low viscosity lubricant, misalignment, higll surface
roughness or ~n in~dequate supply of l~bri~nt. ~7ith
bound~ry lubricntion, chen~ical add~ eives in th~
lubricating composi~ion and chemical met~llurg~ c~l,
~nd mechanic~1 f~ctors in~olvin~ the two rubbing
surfaces will deter~lne the extent of we~r ~nd the
degree of frictlon.
Under boundary cond~tlons of lubrieation, met~l
contact through the oil film result~ in ~unctions of
asperi ties ~nd subsequent lae~al tearing on
microscopic scale. As loads incre~se these conta~ts
become more frequent and result in more pl~sti~
de formAtion, h~gher ~emper~eures and welding with
~elzure eventually o~currine on a ~ross and
de~st~tlng sc~le, Hypoid gear~, since ~hey ~mpose
severe sllding condition~ in comblnAtlon with high
contact seress ~re pArt~culArly ~u8ceptible to thls
~ype of damage. The org~nic lubri~arlt fllm normelly
present becomes ineff~ctive under the ~ ntense heat
whlch le~ds to very h~Bh surface temperatures.
To combat welding under such extreme condieions~
ex~relae pres~ure lubricants were de~eloped. Sllch
lubricAnts contflin ~dditi~e~ which re~ct at the hlgh

1 337292
-3-
contact te~perature~ to form high-meltlng ino~nic
lubricant fllms on the met~1 ~urface~ which prevent
massive welding And bre~k~own. Generally, these
additives consist of sulphur, c~lorine, pho~phoru~ ~nd
lead co~pounds which act eit~er by providing l~yer~ of
low shear strength to m~nimi~e metal ee~rin~ or by
servin~ as fluxing agen~s ~o con~amin~te the metal
surface snd prevent welding. Since ~11 extreme-
pressure additiveg are affected by chemlcal ~ction,
l.e. the ormation of covalent bonds, their use i~
generally avoided to elimina~e posælble eorrosion
difficul~ie~ .
Dry sliding, which involves solid-to-solid
contactl not infrequently exists, e~en when adequ~te
flul~ fil~ lubricat~on is provided. ~ry sliding can
occur for example, in st~rtin8 up of a machlne~ with
~isal~gn~ent or ~n~dequate clearance dur~ng run-in,
during reversal o~ direction, ~nd during any de~ay~ or
interruptions in ~upply of t~e lubric~ting fluid.
Where conventional oils snd gre~e~ cannot be used
becAuse of extreme temperature~l hig~ vaeuum,
radi~t~on, or e~ntaminatlon, ~h~n coatlngR of dry
lubrlcant6 ha~e been appl~ed to reduce the ~igher
fri~tion and more extens~ve we~r which otherwise
obtaln on rubbln~ ehe structurRl mAterl~ls ~g~inst
each oeher.

1 337292
-4-
Thu~ the gofll of lubrlcation 1~ eli~ination of
this wear and minim~sing of fri~ion wh~¢h would
other~ise be encounte~ed in dry sl~ding. Whil~t th~s
c~n be ~ccomplished by complete sepsration of the
rubbing surf~ce6 fl8 ~y a full film of fluid lubrie~ntJ
gener~lly ~uch compleee separAtion i~ not possible
under all working cond~tions ~nd 88 a re~ult, ~urface
~hemical effects h~ve been ~roug~t lnto play in
boundary lubrication to reduce fr$ctLon and we~r which
doe& occur in bound~ry lubricflt~on. Thus anti-wear
a8ent~ have been ~dded to liquid lubtic~nts wh~ch
produce a surf~ce film on the sl~ding p~rts by eiehe~
a chemi~al or physlcAl adsorption mechanism, the film
redu~in~ friction and wear under boundary lubrication
conditions .
A wide variety of compounds have been used fo~
impro~ing lubrication under boundsry film ~onditions.
Thus compound~ containing oxygen such BS fa~ty acids,
esters snd ketones~ co~pou~ds cont~ining ~ulphur or
co~bin~tions of oxygen ~nd sulphur, organ~c chlor~ne
compounds suc~ as chlorinated ~xes~ organic ~ulphu~
compount~ ~uoh ~ ~ulphurlsed fa~ and ~lphurised
olefine~ compounds containlng bo~h chlorine and
sulphu~, org~nic pho~phorou~ compounds such ~s
tricregyl pho6phate, th~opho~ph~tes and phosph~tes ~nd
~1BO org~n~c le~d compounds h~ve been u~ed,

1 337292
-5 -
When t~e cond~ tions in bound~ry lubric~t~on are
mild, polar additlves h~v~ng fl pol~r group ~t one end
o~ the mole~ule ~Q~ A ~olubll~sing group ~t the other
- usu~lly a long chsin ~ydroc~rbon ~o effect
solubili~ation in the lubricsting o~l, hAve been used
to provide ~n ~dherent ~d~orped film over metall~c
~urf~ce~. A clas~ of heterocycllc co~pounds usefu~ B8
additi~res ~rhich provide ~riction modifie~tion ~nd
ilnproved fuel economy are d~selosed in WO 87/0596 ~nd
h~ve the gener~l formula:
(~~Y
~C~X)e
A A A
Il 1i 11
wherein Z iB S, NR, N-C~ , NC~ , N-C-R, PR or PRA,
where~ n A i~ O or S And R is H, Al~cyl, alkenyl,
hydrocarbyl ~cyl, hydrocarbyl phenolate or - (CH~)mQ,
w~ere m i~ 1 to ~bout 12, and Q is O-alkyl or N-Alkyl,
X ls independent ly H, ~OOH, NH2 ~ CONH2, NHNH2 OR
COR, NHR, OH, S~, or CN wherein R i~ the 8~me R8
defined ~bove; p i8 0 ~o 7; e i8 0 t:o 2 wherein e+p i8
2 to abou~ 4; T is NH2~ M~R wherei~ R is the sAme a~
deflned ~bove, SH, 0~ or their t~utomers~ hydrocarbyl
A
acyl or hyd~ocarbyl phenolflte; ~nd Y i8 ~N, ~NH2~ C02H

1 337292
-6--
or CH2NH2 wherein A is the 8~me as defined ~bove.
Such ~dsorped fllms of ~dditive h~ve h~therto only
been ~ucces~ful under rel~ti~ely mild bound~ry
lubricatlon cond~tions, primar~ly becau~e the
thicknes~ of ~uch filmOE i8 very low ~nd usually of the
order of one nanometer. Vnder more severe cond~tions
of boundary lubriç~tion, sub6tances llke ~r~cre8yl
phosphAte or zinc dislkyl dithiophosphates hAve been
foun~ nece6sary and in ex~eme rubbing conditions
where severe metal-to-met~l contact would ot~erwise be
encoun~ered~ ~ctive sulphur, chlorine and lead
compounds h~ve been found essen~iAl. Such ~dditives
ho~ever react chemically to form low shear 6trength
surface layers suc~ as lead sulph~de ~on ~hloride or
ion sulphide. ?h~Y sllrf~ce l~ye~ then prevent5
destruc~ive welding, exce~ive metal tr~nsfer and
severe surface breakdown, Such che~ical reactivi~y
~ith the ~urfAces of t~e sliding p-rtY however ig not
in general desirable ant iR only undertaken when no
other alternati~e iR av~lable.
A~ indicated, the pol~r type of compound which
forms an adherent ~d~orped f~lm o~er the mo~ng
surfaces i8 much to be preferred, but the thicknesses
of ~uch fil~8 w~ich ~ve been possible by the u~e of
hitherto known ~ddit~e~ ln lubrica~ng compo~tions
h~ve produced in~ufficient thickne8se8 of fldsorped

1 3372q2
-7-
f~lm to funct~on under ~ny eond~tion~ ot~er tha~ mild
condition&.
~ t is an ob~ece of the present in~ention to
provlde a lubri¢ating regime whereby adherent ~dsorbed
f~lms of pOlflr mAteri~l ~re provided l~p to 1,000 times
thicker than ha~e hi~her~o been poss~ble.
The present ln~ention ~oncerns a ratic~1 ad~ance
~n lubrication by pro~iding A regime ln which
~ultimolecul~r layers ~re adsorbe~ onto the surf~ces
to be protected thUfi enAbling co~parAtlvely thick
pro~ective film~ to be built up on suface~ sub~ec~ to
fr~ctional ~e~r. Ie has now been found that certain
molecules hAve ~he property of forT~$rlg such
mult~molecular l~yers w~en con~acted with the surface
as by incorporation In a carrier which i~ eontinuou~ly
or intermi~tently brought into cont~ce with ~t lea~ a
portion of the ~urface to be protected. The ~olecules
~-~ich ha~e been found to ~ve t~ s property are
e~sentially ~ingle or eondensed unsaturated ring
sy6tem~ which co~prl~e ~t le~t one ~ix~membeted
unsaturAted he~erocycllc ring co~rising flt leAst one
heterocycll~ moiety whi~h flCt8 a4 ~ hydro~en ~cceptor,
t~le molecule Al80 compr~sing at les~t one hydrogen
donor moiet~, The molecule~ may ~omprise other f~ve
or 8 ~x-membered unsatur~ted ring6 w~ich ~ogether with
t~e s~id 61x-membered un~turated heterocyclic rin8
form ~ eonden~ed r- ng syBtem.

1 3372q2
-8-
~ he multimolecular layers of the lubricAtlng
re~ime of the pre~ent lnven~ion ~re ~uilt up ~y
initial ~dsorption of a layer of molecule~ onto the
surface to be proeected $ollo~ed by ~d~orption of
further molecules onto the initial layers to for~ a
second layer and yet further adsorption to form more
layers untll films up to about l ~lcrometer thick ~re
formed. ~i~hout ~lshing to ~e bound by theo~y it
believed tha~ presence of both hydrogen donor and
~ydrogen ~ceep~or mo~etie~ in the heteropolar
molecules enable~ thi~ ad~orption to take place.
Whilst unsubstitu~ed heteropol~r m~lecules are
prefer~ed sub6tituents ~y be present on the
eteropolar molecule~ prov~ded they do not ~lngly or
collec~ively prevent interaction of the hydro.e.en donor
~nd acceptor ~oieties as by ~teric hindrance. T~us,
for example, hydrocArbon ~ubstituents such as Alkyl
~roup~ should not con~ain mo~e ehan four carbon AtomS
preferably not more than two carbon atoms. W~en the
~ub~tit~ent is ortho to either the heteroato~ or the
hyd~oxyl group the ~teric hindr~nce effe¢e ig likely
to be ~reate~ than when said ~ubstituent is in the
met~ or p~ra po6itlon to either the heteroa~om or 4
hydroxyl gro~p. Alkene and alkyne subst~ent~,
carboxy~ cont~ini~g and ~mi~e cont~ning sub~tuents
~ill all effect the ~ctl~ity of ~he he~eropol~r
molecules and should be svoided.

1 337292
g
In one embodiment of the invention ~he~efore, a
method i~ provided of reduclng wear on a ~urfHce ~hlCh
i8 sub~ect to frietionsl forces which compri~es
forming and ~aint~ining on said ~urface ~ pro~ective
layer composed of ~wo or more ~olecula~ layers of B
heteropol~r compound ¢o~pri~lng at least one
uns~turated heterocycllc s~x-membered ring in which at
least one hetero~to~ moiety ~cts a~ a hydro~en
acceptor and ~n which said compound al80 compri6e~ at
lea~t one hydrogen donor moiety, ~aid heteropolar
co~pound h~ving no substituent which by itse~f or
to~ether with another 6ubstituent or subs~i~uent~
create~ such ste~ic h$ndrance and/or ~ender~ the
molecule so b~sic or acid$c or so alter~ the ~teric
geometry of the molecule as to prevent interaction of
the hydrogen donor and acceptor mo~e~ies of ~ne
molecule of heteropol~r co~po~nd with the hydrogen
donor and ac~eptor moiecles of ~nother molecule of
said heteropolar compound.
For~ation of the multimoleculAr layer of
heteropol~r molecules mRy be effected by incorporaeing
the heteropolar co~pound in e~rrier whlch i~ ~rought
into contact ~ith the surface to be lubricated. It
has been found that the heteropolar molecules ~lgrate
~hrough the carrier onto ehe ~rface to be lubricated
~nd bu~ld up on th~t surf~ce ~o fo~m multi~ole~ula~

1 3372q2
- l o-
layers. The e~rrier m~y be a liquid such as ~n oil or
grease or may even be aqueous . Sol $d c~rrlers ~re
al~o fe~s~ble Quch as poly~mide pl~tlc~ such ~8 those
used eo build up worn machi~ery parts ~uch ~8 d~ive
sh~fts and the like. Inco~por~tion of a heteropolar
compound in the plastic material en~blec ~
multimoleculAr layer of heteropolar molecules to form
not only on the surf~ce of t~e pl~stic by m~gr~tion
throug~l the plAstic material b~t also by tr~nsfe~ from
the surface of the plastic to ano~er surfAce ~hich
rubs ag~inst the surface of t~e plast~c.
It has 81t~ been found ehe.t ~lle heteropol~r
molecules m~gr~te laterally o~er the surf~ce on wh~ch
~hey are ad~orbed beyo~d the boundarles of contact of
that surface with the ~rrier ~ateri~l. Cont~ct of
the c~rrier ~th t~e ~ole of the surface to be
pro~ected ~8 not therefore necess~ry $n order to form
a lubricating l~yer of heteropol~r molecule~ over al 1
the ~ur~ce to be protected. Nor ~s lt necessary to
ha~e continuou~ contac~ between c~rrier ~nd surf~ce to
be treated, but intermlttent contact is also
effective. The ~ult$mole¢ulsr l~yer is not of course
formed in~tant~neously but builds up over ~ per~od of
ti~e. Relative mo~ement of cArrler and ~urface ~o be
protected aceelerate t~e ~orm~tlon and m~$nt~inanee of
the multimoleeul~r layer of hete~opol4r molecules on
the 8urface to be prote~ted.

-11 1 3372~2
The heteropolar molecules ~lgrRte t~rough the
c~rrier ~o the interf~ces of the c~rrler wit~ the
su~roundlng environ~ent. Unsub4tituted heteropolflr
heterocyclic un~aturated sin~le or conden~ed ring
system~ hRv~ng the afore~ent~oned hydrogen donor and
acceptor moiet~e~ ha~e this property of migr~tion.
Any -~ubstituents in such heteropolar molecu~e~ should
not exert such a solubilizing effect on the
heteropolar molecules that they lose their ~bility to
mi~rate thro~h the c~rrier to the ~ neerfaces of the
c~rrier'~ en~iron~ene. Since _ m~or ~pplication o~
~he eompounds o~ the in~ention i~ ~n oils and greases
it is e~ent~ ~1 ehnt t~e molecule~ ~hould no~ exe~t
8UC~ a solubilizing effect that they f~il to migr~te.
~onsequent~y, where they are ~o be ~dded to oils and
gre~ses ~ny substituted groupings should not "over
solubilize" the molecule. Therefore hydrocsrbon
substituents should not ~ontain ~ore than 4 eQrbon
~toms I preferably not more than 2 carbon ~oms-
According to snothe~ embodiment o~ the presentinven~ion there is provided a composi~ion h~ving
~nti-surface weAr properties comprising a c~rrier and
di4sol~ed ~nd/or disperse~ therein ~n effecti~e ~mount
of ~ compound h~ving an~-surface wear properties
char~cterised in that sa~d compound ~ a heteropol~r
compound comprising at least one wholly unsaturated

1 337292
-12-
heterocyclic ~ix-membered rlng in which ~t least one
unsub~tituted heteroatom ~oieey a~t8 fl~ ~ hydrogen
acceptor ~nd in which s~id compound fllso compri~es ~t
le~t one ~ydrogen donor moiety and in wh~ ch 6a~d
heteropolAr ~ompound ~8 no substituent whlch by
itself or together wie~ Rnother substituent or
substltuents creAtes ~uch 6teric hindrance ~nd/or
~ender~ the molecule 80 ba~ic or ac~dic or 80 alters
the steric geometry of ~he molecule ~ to prevent
interaction of t~e hydrogen donor ~nd acceptor
~o~et~es of one molecule of the heteropol~r compound
with the hydrogen ~onor ~nd ~cceptor moietie~ of
ar.~t~er molecule of the heteropolar co~pound nor sny
substituent which by it6elf or together with anotl~er
subs~ituent or sub~tituent8 has the effec~ of
solub~ ing said ~eteropol~r ~ompound in tbe ~elected
c~rrier to the extent th~t migration of the
~eteropol~r co~pound eo the interfaces of ~he carrier
with the CArr~ er environment ~ ~ prevented .
Tbe carrler m~y be a liq~i~ such fl8 ~ lubricating
oil or ~ydrocarbon fuel for an internal combustlon
eng~ne or flqueous 8ystem, or the carrier ~ay ~e a
greAse or sem$-solid m~ter$al (non-Newtonian flu$d)
such ~ bricat~ng greA~e or g~eAge-l~ke
~ubrican~. The cArrier m~y Also be a solid such as ~
pla8tic8 com~o~lte, e.g. a polyamide used ~n repa~ing

1 3372q2
-13-
or rebullding be~dlng surfaces. In the csse of liquid
the content of heteropolar co~ound ~y be from 0.5%
to 4% by weigh~ b~ed on the totAl welghe of earrler
and additi~e and ~n the c~se of grea6e~ or
non-Newtoni~n fluld~ may be fro~ 3X to lOZ by weight
ba~ed on ~e tot~l ~eight of e~rrier plufi ~dtiti~e.
Prefer~bly, in the cese of A liquid the contene of
heteropol~r compound i~ gre~ter than lZ~ e.g. from
l.lZ to 4% by weight ba~ed on the total weight of
carrier and Addieive. The concentration ne~e~ry in
~ solid carrier will depend on ~he type of ~olid
c~rrier lnvolved. In the ~a~e of polyamides 80~ewhat
more ~dditl~e is ~ n general nece8s~ry th~n thAt
required in a semi-soli~ for equivalent resul~s. This
~.~ the ca~e of ~ 'Poly~m~d' be~r~ng lO~ by welght
based on the tOtfll wei~ht of 'Polyamidl' and additive
was found satisf~ctory. However ~mounts of greater
than 10~ e . g . 10 .1% to 20Z are preferred .
The preferred hydro~en ~cceptor moiety is one
in~olvin~ nitrogen AS the heteroatom ~n the for~ of ~n
-N~ moiety. The preferred hydrog¢n donor mo~ety l~ a
hydroxyl group. Both 8UC~ mo~etie8 occur ~n the
prefe~red heteropolAr compound of the in~ention which
i~ 8-hydroxyquinoline:-
-
~,~

1 337292
-14-
The con~ensed ring sy~tem in the heteropolsr compounds
u~eful in the invention m~y cone~1n up to four -N-
moieties. ~ith prefer~bly up to two such moieties
bein8 ~ncorpor~ted ~ ring form~ng a~o~s in ~ny one
~in~. Ot~er unsubs~ituted heteropol~ compound~
u~eful in the method And compos~tions of the pre~ent
invention incl~de:
7,3 dihyd~oxypyridine
~u
~l H
4,6 ~ihydroxypyrimidine
WQ~
2 pteridinol
w4
2,4 quinolindiol ~
~~0~
2 , 3 d I hyd roxyq u 1 n ox a 1 I n ,i~
~æ~Lo ~
2.4 pterldinedlol ~ ~ ~
W~

1 337292
6 p~rinol O
t~
~-0
3 phenanthridinol
2 phenanthrolinol
2 phenazinilol ~
A~ previously ind~cated the preferred heteropolar
compound6 ~re uns~bstitued materl~l~. Substituents
should not create steric hindr~nce w~ich prevents
interaction of the hydrogen donor and ~cceptor
moietie~. T~lus the provision of ~ ethyl group ortho
to the -N- hyd~ogen ~cceptor mo~e~y of 8-hyd~oxy-
quinoline to form the compo~nd:-
~2-met~yl-8-hydroxy ~uninoline

1 337292
-16-
does not nl~terl~lly affec~ the ~etivity of this
heteropolAr molecule in forming edsorption film on
metal sur~ceo. The number a~d size of the
~ubstituent~ which can be toler~ted ~n ~he he~eropolar
molecule depends on the number and posi~on of the
hydrogen donor ~nd sceeptor moieties ln the molecule.
In gener~l t~e ~ubst~tuen~s groups should not exceed
four atoms in number (e.g. in the case of hydro~arbyl
the bu~yl group), preferably no ~ore th~n ~o fl~oms
~nd more preferably stlll only one e~rbon atom.
A good lndic~eion of whether ~terlc hindr~nee ~s
1 ikely to c~u~e problealfi i8 given by me~sur~ ng the
~dsorption-free energy of the compound in ~ue~tion.
If the s~orpeion-free energy fl~ me~sured on ~ copper
surface is sub~t~nti~lly in the range of 3 to 6
Kc~l/mol then R teric hin~r~nce i8 unlikely ~o be
problem .
Th~a invention will be further lllustraeed by
reference to the following Examples w~l~ch ~re purely
illu8tr~tive. In e~ch of the exa~ples the heteropol~r
compound was 8 -hydroxyqulnol lne .
~LE 1
0 . 5% by we~ght of heteropol~r compound wa~
incorpor~ted in S~E 30 engine oll which we~ then u~ed
in ~ ee6t-bed fully ~nstrumented W~irlepeel sy~eem.
The following re~ult~ were obtalned ~ ~hown ln Tables
1 to 5.

_17_ 1 337292
Table 1
C:OMPR~S~~
CYLIN~ 1 2 3 4 5 6 1 2 3 4 5 6
C~PRESSICN, lOSP~28 22 26 ~4 ~4 2230 30 28 26 26 26
Tablc 2
EU~ ~ONStk~I~ (af~er lOO km of r~mning)
HEI~a~ AETER 15 ,000 km
Rll~X:
COt~SUPTl~N UI~ lOOl~ AT ~ SPEED CF
4C)~h 5~ 60~h 701~m/h
(a) 22.83 27.39 33.55 42.73
(b) 20.~6 ~5.97 31.25 39.84
(c) 20.32 23.47 28.4~ 35.5g
T~le 3
WEA~ RAl~:S
WI~ HETE~LAR 0-0068 ~e/~
WIlH HE~OE~AR 0.003g Fe/ha~
T~ble 4
E~Cr~
t~.~ ~LAR 170.5 l~a ER~Cl~N MIDI~E E~E
162.5 kP~ ~'

-18- 1 337292
Table 5
EMISSION (Bo~ch Unit~
(~) Ground Revs (Tick-o~rer 6peed)
(b) Full Throttle (Revs)
1 . 5 MAX PERMISSI~LE VALUE
WIlHO~JT HETE~OPOLAR WITH HETEROPOLAR
(a) (b) (-) (b)
0.9 1.7 0.6 1.2
The followin~ Ex~mples show the EP effect of adding t~le
heteropol~r compound to different lubricant6.
EXAMPI.E 2
~X'rRE?lE PRESSURE (EP) E~FECT
She l l Four Ba l l M~chine
Lubr~c~ng ~'eàium; Lithium grea&e, with 3Z by welght
of ~eteropolar co~pount.
WITIIOUT HETEROPOLAR welding at 27 - 2.27N
l~JITH llETEROPOLAR no welding at 37
E;XA~PL E 3
F~LEX LtJBRICANTS TESTER
To . L .P . Test 241t69 with O ~ 5X by weight of heteropol~r
co~potJnd .
JAW L~D TIME TO FAILURE
S~E OIL WIT~lOUT ~IETEROP~LAR 3 ,OOON 3 m~ n lO 6ecs
SAE OIL WITH l~:TE~OPOLAR 4,000N 5 min
~ote: JQW LOad 1000N increments for a period o~ one
minute .

1 3372q2
-19-
EXAMPLE 4
CO~POS7 TE MATERIALS
'Polyamid' Be~ing w~ th lO~ of MoS2 co~posite
additive, compared with a s~alilar bearing cont~ining
1070 of heteropolsr compound. The bearlng h~ving the
heteropolar compound in the ' Polyamid ' lowered the
fri~tiol~ by 30% ~18 compound ~o ehe bearing cont~ining
t!le MoSz additive,
EXAMPLE 5
NOISE REI~ TION
When t~e heeeropolar compou~d ~ incorpor~ted in
t~e lubricant in ~ ba~k ~xle dlffeten~isl 8earing ~he
noise redllced by ZdB. When the heteropol~r compound
~AS incorporAted in the lubricant in a Vauxhall As tr~
en~ ~ne ehe noise decreased by 8~dB to 80dB.
................................................ ~