AU622912B2 - Method of and compositions for reducing wear on surfaces subjected to frictional forces - Google Patents

Description

7 i: i i ANNOUNCEMENT OF THE LATER PUBUCATION OF INTERNATIONAL SEARCH REPORTS PCIrr INTERNATIONAL APPLICATIOIBH~9UC.OR P T COOPERATION TREATY (PCT) (51) International Patent Classification 4 V (1nternatonalPIillication Number: WO 89/11518 133/38, 133/40 A3 1/22 International Publication Date: 30 November 1989 (30.11.89) (21) International Application Number: (22) International Filing Date: PCT/GB89/00530 17 May 1989(17.05.89) Priority data: 8811696.7 18 May 1988 (18.05.88) (81) Designated States: AT (European patent), AU, BE (European patent), CH (European patent), DE (European patent), DK, Fl, FR (European patent), GB (European patent), HU, IT (European patent), JP, KR, LU (European patent), NL (European patent), NO, SE (European patent), US.

Published With international search report Before the expiration of the time limit for amending the claims and to be republished in the event of the receipt of amendments.

(88) Date of publication of the international search report: 8 February 1990 (08.02.90) (71) Applicant (for all designated States except US): NATIONAL RESEARCH DEVELOPMENT CORPORATION [GB/GB]; 101 Newington Causeway, London SEI 6BU

(GB).

(72) Inventors; and Inventors/Applicants (for US only) FODOR, Josef [HU/ HU]; Naphegy, Ter 5/B, H-1016 Budapest (HU).

SCHOFIELD, Jack [GB/GB]; 12 The Paddock, Upton, Wirral, Merseyside L49 6NP (GB).

(74)Agent: W.P. THOMPSON CO.; Coopers Building, Church Street, Liverpool LI 3AB (GB).

(54)Title: METHOD OF AND COMPOSITIONS FOR REDUCING WEAR ON SURFACES SUBJECTED TO FRIC- TIONAL FORCES (57) 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 frictional wear. The molecules having this 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.

89/11518 PC/GB89/00530 WO 89/11518 -1-

DESCRIPTION

"METHOD OF AND COiPOSITIONS FOR REDUCING WEAR ON SURFACES SUBJECTED TO FRICTIONAL FORCES" The present invention relates to a method of, and compositions for, reducing wear on surfaces subjected to frictional forces, particularly between moving surfaces.

The primary purpose of lubrication is separation of moving surfaces to minimise friction and wear.

Several distinct regimes are commonly recognised in the field of lubrication. Thus in fluid film lubz-ication the load is supported entirely by pressures within the separating fluid film. This film pressure is frequently generated by relative motion of the surfaces involved, which pumps the lubricant into a converging, wedge-shaped zone. The hydro dynamic behaviour of such bearings is completely dependent on the viscous behaviour of the lubricant. Both the load-supporting oil film pressure and the power loss are functions of lubricant viscosity in combination with the geometry and shear rate imposed by the bearing operating conditions.

As the severity of operating conditions increases, a point is eventually reached where the load can no longer be carried completely by oil-film support.

High spots, or asperities of the mating surfaces must pCT/Gi'S1O0530 WO 89/11518 -2then shear with the lubricant in load support and the lubrication regime shifts from full-film to mise@d-film and then to complete boundary high load, low speed, low viscosity lubricant, misalignment, high surface roughness or an inadequate supply of lubricant. With boundary lubrication, chemical additives in the lubricating composition and chemical metallurgical, and mechanical factors involving the two rubbing surfaces will determine the extent of wear and the degree of friction.

Under boundary conditions of lubrication, metal contact through the oil film results in junctions of asperities and subsequent metal tearing on a microscopic scale. As loads increase these contacts become more frequent and result in more plastic deformation, higher temperatures and welding with seizure eventually occurring on a gross and devastating scale. Hypoid gears, since they impose severe sliding conditions in combination with high contact stress are particularly susceptible to this type of damage. The organic lubricant film normally present becomes ineffective under the intense heat which leads to very high surface temperatures.

To combat welding under such extreme conditions, extreme pressure lubricants were developed. Such lubricants contain additives which react at the high i S ,WO 89/11518 PCT/GB89/00530 -3contact temperatures to form high-melting inorganic lubricant films on the metal surfaces which prevent massive welding and breakdown. Generally, these additives consist of sulphur, chlorine, phosphorus and lead compounds which act either by providing layers of low shear strength to minimise metal tearing or by serving as fluxing agents to contaminate the metal surface and prevent welding. Since all extremepressure additives are affected by chemical action, i.e. the formation of covalent bonds, their use is generally avoided to eliminate possible corrosion difficulties.

Dry sliding, which involves solid-to-solid contact, not infrequently exists, even when adequate fluid film lubrication is provided. Dry sliding can occur for example, in starting up of a machine, with misalignment or inadequate clearance during run-in, during reversal of direction, and during any delays or interruptions in supply of the lubricating fluid.

Where conventional oils and greases cannot be used because of extreme temperatures, high vacuum, radiation, or contamination, thin coatings of dry lubricants have been applied to reduce the higher friction and more extensive wear which otherwise obtain on rubbing the structural materials against each other.

PCT/GB89/00530 WO 89/11518 pr/GB89 -4- Thus the goal of lubrication is elimination of this wear and minimising of friction which would otherwise be encountered in dry sliding. Whilst this can be accomplished by complete separation of the rubbing surfaces as by a full film of fluid lubricant, generally such complete separation is not possible under all working conditions and as a result, surface chemical effects have been brought into play in boundary lubrication to reduce friction a'id wear which does occur in boundary lubrication. Thus anti-wear agents have been added to liquid lubricants which produce a surface film on the sliding parts by either a chemical or physical adsorption mechanism, the film reducing friction and wear under boundary lubrication conditions.

A wide variety of compounds have been used for improving lubrication under boundary film conditions.

Thus compounds containing oxygen such as fatty acids, esters and ketones, compounds containing sulphur or combinations of oxygen and sulphur, organic chlorine compounds such as chlorinated waxes, organic sulphur compounds such as sulphurised fats and sulphurised olefines. compounds containing both chlorine and sulphur, organic phosphorous compounds such as tricresyl phosphate, thiophosphates and phosphites and also organic lead compounds have been used.

WO89/11518 PCT/GB89/00530 'WO 89/11518 When the conditions in boundary lubrication are mild, polar additives having a polar group at one end of the molecule and a solubilising group at the other usually a long chain hydrocarbon to effect solubilisation in the lubricating oil, have been used to provide an adherent adsorped film over metallic surfaces. A class of heterocyclic compounds useful as additives which provide friction modification and improved fuel economy are disclosed in WO 87/0596 and have the general formula: (C )p

(I)

CHX)e A A A i II II wherein Z is S, NR, N-C-AR, NC-NHR, N-C-R, PR or PRA, wherein A is 0 or S and R is H, alkyl, alkenyl, hydrocarbyl acyl, hydrocarbyl phenolate or -(CH2)mQ, where m is 1 to about 12, and Q is O-alkyl or N-alkyl, X is independently H, COOH, NH 2

CONH

2

NHNH

2

OR,

COR, NHR, OH, SH, or CN wherein R is the same as defined above; p is 0 to 2; e is 0 to 2 wherein e+p is 2 to about 4; T is NH 2 NHR wherein R is the same as defined above, SH, OH or their tautomers, hydrocarbyl

A

II

acyl or hydrocarbyl phenolate; and Y is CN, CNH2, C02H 8 pCT/GB89/00530 WO 89/11518 -6or CH 2

NH

2 wherein A is the same as defined above.

Such adsorped films of additive have hitherto only been successful under relatively mild boundary lubrication conditions, primarily because the thickness of such films is very low and usually of the order of one nanometer. Under more severe conditions of boundary lubrication, substances like tricresyl phosphate or zinc dialkyl dithiophosphates have been found necessary and in extreme rubbing conditions where severe metal-to-metal contact would otherwise be encountered, active sulphur, chlorine and lead compounds have been found essential. Such additives however react chemically to form low shear strength surface layers such as lead sulphide ion chloride or ion sulphide. This surface layer then prevents destructive welding, excessive metal transfer and severe surface breakdown. Such chemical reactivity with the surfaces of the sliding parts however is not in general desirable and is only undertaken when no other alternative is available.

As indicated, the polar type of compound which forms an adherent adsorped film over the moving surfaces is much to be preferred, but the thicknesses of such films which have been possible by the use of hitherto known additives in lubricating compositions have produced insufficient thicknesses of adsorped SWO 89/11518 PCT/GB89/00530 -7film to function under any conditions other than mild conditions.

It is an object of the present invention to provide a lubricating regime whereby adherent adsorbed films of polar material are provided up to 1,000 times thicker than have hitherto been possible.

The present invention concerns a radical advance in lubrication 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 sufaces subject to i frictional wear. It has now been found that certain molecules have the property of forming such multimolecular layers when contacted with the surface as by incorporation in a carrier which is continuously or intermittently brought into contact with at least a portion of the surface to be protected. The molecules which have been found to have this 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, the molecule also comprising at least one hydrogen donor moiety. The molecules may comprise other five or six-membered unsaturated rings which together with the said six-membered unsaturated heterocyclic ring form a condensed ring system.

PCT/GB 8 9 /00 5 3 0 22 June 1990 -8- The multimolecular layers of the lubricating regime of the present invention are built up by initial adsorption of a layer of molecules onto the surface to be protected followed by adsorption of further molecules onto the initial layers to form a second layer and yet further adsorption to form more layers until films up to about 1 micrometer thick are formed. Without wishing to be bound by theory it is believed that presence of both hydrogen donor and hydrogen acceptor moieties in the heteropolar molecules enables this adsorption to take place.

Whilst unsubstituted heteropolar molecules are preferred substituents may be present on the heteropolar molecules provided they do not singly or collectively prevent interaction of the hydrogen donor and acceptor moieties as by steric hindrance. Thus, for example, hydrocarbon substituents such as alkyl groups should preferably not contain more than four carbon atoms, preferably not more than two carbon atoms. When the substituent is ortho to either the heteroatom or the hydroxyl group the steric hindrance effect is likely to be greater than when said substituent is in the meta or para position to either the heteroatom or a hydroxyl group. Alkene and alkyne substituents, carboxyl containing and amine containing substituents will all effect the activity of the S heteropolar molecules and should be avoided.

SJRATITI ITF qHFFT PCT/GB 89/00530 22 June 1999 -9- In one eimbodiment of the invention therefore, 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 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.

Formation of the multimolecular layer of heteropolar molecules may be effected by incorporating the heteropolar compound in a carrier which is brought into contact with the surface to be lubricated. It has been found that the heteropolar molecules migrate throtgh the carrier onto the surface to be lubricated and build up on that surface to form multimolecular

A

S I

SHEET

v SUBSTITUTE

SHEET

I PCr/GB89/0053 0 WO 89/11518 layers. The carrier may he a liquid such as an oil or grease or may even be aqueous. Solid carriers are also feasible such as polyamide plastics such as those used to build up worn machinery parts such as drive shafts and the like. Incorporation of a heteropolar compound in the plastic material enables a multimolecular layer of heteropolar molecules to form not only on the surface of the plastic by migration through the plastic material but also by transfer from the surface of the plastic to another surface which rubs against the surface of the plastic.

It has also been found that the heteropolar molecules migrate laterally over the surface on which they are adsorbed beyond the boundaries of contact of that surface with the carrier material. Contact of the carrier with the whole of the surface to be protected is not therefore necessary in order to form a lubricating layer of heteropolar molecules over all the surface to be protected. Nor is it necessary to have continuous contact between carrier and surface to be treated, but intermittent contact is also effective. The multimolecular layer is not of course formed instantaneously but builds up over a period of time. Relative movement of carrier and surface to be protected accelerate the formation and maintainance of the multimolecular layer of heteropolar molecules on the surface to be protected.

PCT/GB 89/00 530 22 June 1990 -11- The heteropolar molecules migrate through the carrier to the interfaces of the carrier with the surrounding environment. Unsubstituted heteropolar heterocyclic unsaturated single or condensed ring systems having the aforementioned hydrogen donor and acceptor moieties have this property of migration.

Any substituents in such heteropolar molecules should not exert such a solubilizing effect on the heteropolar molecules that they lose their.ability to migrate through the carrier to the interfaces of the carrier's environment. Since a major application of the compounds of the invention is in oils and greases it is essential that the molecules should not exert such a solubilizing effect that they fail to migrate.

Consequently, where they are to be added to oils and greases any substituted groupings should not "over solubilize" the molecule. Therefore hydrocarbon substituents should preferably not contain more than 4 carbon atoms, preferably not more than 2 carbon atoms, According to another embodiment of the present invention there is provided a composition having anti-surface wear properties comprising a carrier and dissolved and/or dispersed therein an effective amount of a compound capable of producing a multi-molecular lubricating layer having anti-surface wear properties characterised in that said compound is a heteropolar compound comprising at least one wholly unsaturated SU;TJTI ITP Cucc-r WO89/11518 PCT/GB89/00 53 0 -12heterocyclic 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 moieuies of another molecule of the heteropolar compound nor any substituent which by itself or together with another 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.

The carrier may be a liquid such as a lubricating oil or hydrocarbon fuel for an internal combustion engine or aqueous system, or the carrier may be a grease or semi-solid material (non-Newtonian fluid) such as a lubricating grease or grease-like lubricant. The carrier may also be a solid such as a plastics composite, e.g. a polyamide used in repairing WO 89/11518 PCT/GB89/00530 -13or rebuilding beading surfaces. In the case of liquid the content of heteropolar compound may be from to 4% by weight based on the total weight of carrier and additive and in the case of greases or non-Newtonian fluids may be from 3% to 10% by weight based on the total weight of carrier plus additive.

P- ferably, in the case of a liquid the content of heteropolar compound is greater than e.g. from 1.1% to 4% by weight based on the total weight of carrier and additive. The concentration necessary in a solid carrier will depend on the type of solid carrier involved. In the case of polyamides somewhat more additive is in general necessary than that required in a semi-solid for eouivalent results. This is the case of a 'Polyamid' bearing 10% by weight based on the total weight of 'rolyamid" and additive was found satisfactory. However amounts of greater than 10% e.g. 10.1% to 20% are preferred.

The preferred hydrogen acceptor moiety is one involving nitrogen as the heteroatom in the form of an moiety. The preferred hydrogen donor moiety is a hydroxyl group. Both such moieties occur in the preferred heteropolar compound of the invention which is 8-hydroxyquinoline: O O w I!~~1J MPr~- ?r r PCrIGB89/00530 WO 89/11518 -14- The condensed ring system in the heteropolar compounds useful in the invention may contain up to four -N= moieties, with preferably up to two such moieties being incorporated as ring forming atoms in any one ring. Other unsubstituted heteropolar compounds useful in the method and compositions of the present invention include: 2,3 dihydroxypyridine 4,6 dihydroxypyrimidine 2 pteridinol 2,4 quinolindiol 2,3 dihydroxyquinoxalin Il~ 0 h 14A 2.4 pteridinediol r WO 89/11518 PC/GB89/00530 6 purinol 3 phenanthridinol 2 phenanthrolinol 2 phenazinilol In As previously indicated the preferred heteropolar compounds are unsubstitued materials. Substituents should not create steric hindrance which prevents interaction of the hydrogen donor and acceptor moieties. Thus the provision of a methyl group ortho to the hydrogen acceptor moiety of 8-hydroxyquinoline to form the compound:o c~ ,-j 2-methyl-8-hydroxy quninoline PC/GB89/00536 WO 89/11518 -16does not materially affect the activity of this heteropolar molecule in forming adsorption film on metal surfaces. The number and size of the substituents which can be tolerated in the heteropolar molecule depends on the number and position of the hydrogen donor and acceptor moieties in the molecule.

In general the substituents groups should not exceed four atoms in number in the case of hydrocarbyl the butyl group), preferably no more than two atoms and more preferably still only one carbon atom.

A good indication of whether steric hindrance is likely to cause problems is given by measuring the adsorption-free energy of the compound in question.

If the adsorption-free energy as measured on a copper surface is substantially in the range of 3 to 6 Kcal/mol then steric hindrance is unlikely to be a problem.

The invention will be further illustrated by reference to the following Examples which are purely illustrative. In each of the examples the heteropolar compound was 8-hydroxyquinoline.

FXAMPLE 1 by weight of heteropolar compound was incorporated in SAE 30 engine oil which was then used in a test-bed fully instrumented Whirlepeel system.

The following results were obtained as shown in Tables 1 to I- PCI/GB89/00530 W089/11518

COMPRESSION

-17- Table 1

CYLINDER

COMPRESSIGt, 10 5 Pa WITHOUr HE=RPLAR 123456 28 22 26 24 24 22 WITH HETEROPOLAR 123456 30 30 28 26 26 26 Table 2 FUEL CONS 14FICOJ (after 100 k of tnning) JImour WITH IETFCPOLAR ITH HFMROPOLAR HETEROPCLAR A=FTR 15,000 km FUEL CONSUMPTION LITRES l00km AT A SPEED OF 401,m/h 50km/h 60km/h 22.83 27.39 33.55 42.73 20.96 25.97 31.25 39.84 20.32 23.47 28.49 35.59 Table 3 WEAR RATES WITHOUT HEMRCPOLAR WITH H=ERCPOIAR 0.006g Fe/hour 0.003g Fe/hour Table 4 170.5 kPa HFUI0ON MIDBtE PRESSJRE 162.5 kPa I FRIcrIcr WITHOUT HETERCPOLAR WITH HETERPCLAR WO 89/11518 PCT/GB89/00530 -18- Table EMISSION (Bosch Units Ground Revs (Tick-over speed) Full Throttle (Revs) MAX PERMISSIBLE VALUE WITHOUT HETEROPOLAR WITH HETEROPOLAR (b) 0.9 1.7 0.6 1.2 The following Examples show the EP effect of adding the heteropolar compound to different lubricants.

EXAMPLE 2 EXTREME PRESSURE (EP) EFFECT Shell Four Ball Machine Lubricating Medium: Lithium grease, with 3% by weight of heteropolar compound.

WITHOUT HETEROPOLAR welding at 27 2.2 7

N

WITH HETEROPOLAR no welding at 3 7

N

EXAMPLE 3 FALEX LUBRICANTS TESTER To. L.P. Test 241/69 with 0.5% by weight of heteropolar compound.

JAW LOAD TIME TO FAILURE SAE OIL WITHOUT HETEROPOLAR 3,000N 3 min 10 sees SAE OIL WITH HETEROPOLAR 4,000N 5 min Note: Jaw Load 1000N increments for a period of one minute.

i i I I WO 89/11518 PCT/GB89/00530 -19- EXAMPLE 4 COMPOSITE MATERIALS 'Polyamid' Bearing with 10% of MOS 2 composite additive, compared with a similar bearing containing of heteropolar compound. The bearing having the heteropolar compound in the 'Polyamid' lowered the friction by 30% as compound to the bearing containing the MoS 2 additive.

EXAMPLE NOISE REDUCTION When the heteropolar compound was incorporated in the lubricant in a back axle differential gearing the noise reduced by 2dB. When the heteropolar compound was incorporated in the lubricant in a Vauxhall Astra engine the noise decreased by 86dB to

Claims (21)

1. A composition having anti-surface wear properties comprising a carrier and dissolved and/or dispersed therein an effective amount of a compound capable of producing a multi-molecular lubricating layer having anti-surface wear properties characterised in that said compound is a Xeteropolar compound comprising at least one wholl, 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 the heteropolar compound nor any substituent which by itself or together with another 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. WO 89/11518 PCT/GB89/00530 -21-

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. A composition as claimed in any of claims 1 to 4, 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 6, in which the lubricating oil comprises at least one unsaturated hydrocarbon.

8. A composition is claimed in claim 7, wherein the heteropolar compound is present in the range 1.1% 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. A composition as claimed in claim 5, in which the carrier is a liquid hydrocarbon fuel for an internal combustion engine. i-t pCr/GB89/00530 WO 89/11518 -22-

11. A composition as claimed in any of claims 1 to 4, 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 by .weight based on the total weight of carrier and additive.

13. A composition as claimed in any of claims 1 to 4. in which the carrier is a solid plastics material.

14. A composition as claimed in claim 13, in which the solid plastics material is a polyamide. A composition as claimed in claim 14, wherein the heteropolar compound is present in the range 10.1% to 20% based on the total weight of carrier and additive.

16. A composition as claimed in any of the preceding claims, in which the heterocyclic moiety which acts as a hydrogen acceptor is an moiety.

17. A composition as claimed in claim 16, in which the heteropolar compound contains up to fcur -N= moieties.

18. A composition as claimed in any of the preceding claims, in which the hydrogen donor moiety is an -OH group. I i i i s o r r r -23-

19. A composition as claimed in any of the preceding claims, in which the heteropolar compound is 8-hydroxyquinoline. A composition as claimed in any of claims I to 18, in which the heteropolar compound is selected from 2,3- dihydroxypyridine, 4,6-dihydroxypyrimidine, 2-pteridinol, 2- methyl 8-quinolinol, 2,4-quinolindiol, 2,3- dihydroxyquinoxalin, 2,4-pteridinediol, 6-purinol, 3- phenanthridinol, 2-phenanthrolinol and 2-phenazinol.

21. 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 by applying to said surface a composition comprising a carrier and a compound capable of producing a multimolecular lubricating layer characterised in that said compound capable of producing a multi-molecular lubricating layer is a heteropolar compound comprising 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 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 -24- 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 the carrier to the extent that migration of the heteropolar compound to the interfaces of the carrier with the carrier environment is preventet.

22. A method as claimed in claim 21, in which the protective layer is formed on the surface to be protected by contacting at least a portion of the said surface with a composition as claimed in any of claims 1 to

23. A method as claimed in claim 22, in which at least a portion of the surface to be protected is continuously contacted with said composition. S24. A method as claimed in claim 22, in which at least a S portion of the surfar to be protected is intermittently contacted with said composition. DATED this 14th day of February, 1992. e NATIONAL RESEARCH DEVELOPMENT CORPORATION Patent Attorneys for the Applicant: PETER MAXWELL ASSOCIATES. i *P INTERNATIONAL SEARCH REPORT international Application No PCT/GB 89/00530 I. CLASSIFICATION OF SUBJECT MATTER (if several classification symbols apply, Indicate all) 6 According to International Patent Classification (IPC) or to both National Classification and IPC 4 IPC4: C 10 M 133/38, C 10 M 133/40, C 10 L 1/22 II. FIELDS SEARCHED Minimum Documentation Searched 7 Classification System Classification Symbols IPC 4 C 10 M, C 10 L Documentation Searched other than Minimum Documentation to the Extent that such Documents are Included In the Fields Searched a II. DOCUMENTS CONSIDERED TO BE RELEVANT' Category Citation of Document, with Indication, where appropriate, of the relevant passages 12 Relevat to Claim No. i3 X US, A, 3779920 DEVRIES) 18 December 1973 1,2,4-6, see abstract; column 1, lines 3-7,20-25,39-60;I 16-19,21- column 2, lines 1-3,18-53, line 68 column 3,j 23 line 6; column 3, lines 14-18, line 66 column 4, line 2; column 4, lines 7-47; column 7, line 43 column 8, line 4; examples 5,6,10,12,13; column 11, lines 36-43; claims 1-4,8,20-24,29 X FR, A, 1577581 GEIGY 8 August 1969 1-3,5,6,16- see page 1, lines 5-21; page 4, lines 1-4; 18 examples 4-6; claims 1-3 A WO, A, 87/05926 (THE LUBRIZOL CORP.) 8 October 1987 cited in the application X US, A, 3779920 DEVRIES) 18 December 1973 7,8 see abstract: column 1, lines 3-7,20-25,39-60; column 2, lines 1-3,18-53, line 68 column 3 line 6; column 3, lines 14-18, line 66 column 4, line 2; column 4, lines 7-47; column 7, line 43 column 8, line 4; examples 5,6,10,12,13; column 11, lines 36-43; claims 1-4,8,20-24,29 y EP, A, 0098717 (NIPPON MINING CO. LTD) 7,8 18 January 1984, see abstract; page 21, line _23 page 22, line 11; claims 1,8,11 Special categories of cited documents: to later document published after the international filing date document defining the general state of the art which i not or priority date and not in conflict with the Cap;lisation but on"A" d mentddefi the e rt which ires nt cited to underatand the principle or theory ur, d s aring the ronsidered to be of particular relevance invention earlier document but published on or after the International document of particular relevance: the calamed invention filing date cannot be considered novel or cannot be considered to document which may throw doubts on priority claim(e) or Involve an Inventive step which is cited to establish the publication date of another document of particular relevance; the claimed invention citation or other special reason (as specifed) cannot be considered to Involve an inventive step when the document rer.frlig to an oral disclosure, use, exhibition or document is combined with one or more other such docu- other means ments, such combination being obvious to a person skilled document published prior to the International filing date but in the art. later than the nriority date claimed document member of the same patent family IV. CERTIFICATIt3N Date of the Actual Completion of the Internatlonal Search Date of Mailing of this International Search Report August 1989 15. 01. International Searching Authority Signature of Ah EUROPEAN PATENT OFFICE T.K. WILLIS Form PCT/ISA/210 (second sheet) (Jauary 1915) international Application No. P CT/ GB 89 00530

111. DOCUMENTS CONSIDERED TO 0E RELEVANT (CONTINUED FROM THE SECOND SHEET Calegory I Citation of Oocumet. with Indication, wrhe a oO Vopiate, of Irm relevant Passages I Relevant to Claim No A US, A EP, A, 0168534 (EXXON RESEARCH AND ENGINEERING Co.) 22 January 1986 A, 3779920 DEVRIES) 18 December 1973 see abstract; column 1, lines 3 7 2 0-25, 29 6 0 column 2, lines 1-3,18-53, line 68 -column 3, line 6; column lines 14-18, line 66 column 4, line 2; column 4, lines 7-47; column 7, line 43 column 8, line 4; examples 5,6,10,12,13; column 11, lines 36- 43; claims 1-4,8,20-24,29 A, 0103737 (BASF AG) 28 March 1984 see abstract; page 1, line 5 page 2, line 20; tables 1,2 Y US, A, 3779920 DEVRIES) 18 December 1973 see abstract; column 1, lines 3-7, 20-25,39-60; column 2, lines 1-3, 18-53, line 68 column 3, line 6; column 3, lines 14-18, line 66 column 4, line 2; column 4, lines 7-47; column 7, line 43 column 8, line 4; examples 5,6,10,12,13; column 11, lines 36-43; claims 1-4, 8,20-24,29 Y US, A, 4295861 BURNS) October 1981 see abstract Y FR, A, 1577581 GEIGY S.A.) 8 August 1969 see page 1, lines 5-21; page 4, lines 1-4; examples 4-6; claims 1-3 cited in the application X US, A, 2030033 McCONNELL) 4 February 1936 see the whole document X EP, A, 0069507 (EXXON RESEARCH AND ENGINEERING CO.) 12 January 1983 see abstract; claims 1-3 X Chemical Abstracts, volume 110, no. 6, 1989, (Columbus, Ohio, US), D. Wei: "Lubricity of fuels. II. Wear studies using model compounds" see page 160, abstract 41666e, Shiyou Xuebao, Shiyou Jiagong 1988, 90-9 9 9 i0 Form PCT ISA:210 (extra sheet) (Jauary IS) e lnterntlonal ADollcation No. PCT/GB 89/00530 III. DOCUMENTS CONSIDERED TO I RELEVANT (CONTINUED FROM THE SECOND SHLET) Category I Citation of Document, with indication, whe soapropfilte. of the relevant passages Relevant to Claim No I X DE, A, 3131950 (NIPPON OIL CO.) March 1982 see abstract, claims 1,4-6; page 4, lines 4-14; tables 4-6; page 18, lines Y US, A, 3779920 DEVRIES) 18 December 1973 see abstract; column 1, lines 3-7, 20-25,39-60; column 2, lines 1-3, 18-53, line 68 column 3, line 6; column 3, lines 14-18, line 66 column 4, line 2; column 4, lines 7-47; column 7, line 36 column 8, line 4; examples 5,6,10,12,13; column 11, lines 36-43; claims 1-4,8,20-24,29 A Y US, A, 3078228 SMITH et al.) 19 February 1963 see column 1, line 11 column 3, line 33; column 6, lines 14-60; example XIII X Chemical Abstracts, volume 97, no. 18, 1982, (Columbus, Ohio, US), see page 165, abstract 147467u, SU, A, 939527 (SPECIAL CONSTRUCTION- TECHNOLOGICAL BUREAU OF SPECIAL MATERIAL MANAGEMENT, NOVOCHERKASSK et al.) 30 June 1982 A A US, A, 3779920 DEVRIES) 18 December 1973 see abstract; column 1, lines 3-7, 20-25,39-60; column 2, lines 1-3, 18-53, line 68 column 3, line 6; column 3, lines 14-18, line 66 column 4, line 2; column 4, lines 7-47; column 7, line 43 column 8, line 4; examples 5,6,10,12,13; column 11, lines 36-43; claims 1-4, 8,20-24,29 11 12 11 11 12 13 13,14 A US, X US, Form PCT ISA 10 (uitra sh A, 4075111 BILOW et al.) 21 February 1978 see abstract; column 1, lines 10-52 A, 3939084 SULLIVAN) 17 February 1976 see abstract; column 2, line 63 e) (Jaftwy inS) Internatlonal Aoitcation No. PCT/GB 89/ 00530 111. DOCUMENTS CONSIDERED TO 9E RELEVANT (CONTINUED FROM THE SECOND SHEET) Category j Citation of Documefrit. with indication, wfewe awgrognitt.. of ttt. (Olevant passages Relevant to Claim No column 3, line 21, lines 51-55; tables I,11 A US, A, 3779920-(D.L. DEVRIES) 18 December 1973 see abstract; column 1, lines 3-7, 20-25,39-60; column 2, lines 1-3, 18-53, line 68 column' 3, *line 6; column 3, lines 14-18, line 66 column 4, line 2; column 4, lines 7-47; column 7, line 43 column 8, line 4: examples 5,6,10,12,13; column 11, lines 36-43; claims 1-4, 8,20-24,29 A FR, A, 2249879 (SOCIETE NATIONALE DES I POUDRES ET EXPLOSIFS) May 1975 Y Chemical Abstracts, volume 95, no. 19, 24 1981, (Columbus, Ohio, US), A.S. Kuzharov et al.: "Formation of coordination compounds under model friction contact conditions", see page 128, abstract 83302k, Zh. Fiz. Khim. 1980, 54(12),

3118-22 Y us, A, 3779920 DEVRIES) 24 18 December 1973 see abstract; column 1, lines 3-7, 20-25,39-60; column 2, lines 1-3, 18-53, line 68 column 3, line 6; column 3, lines 14-18, line 66 column 4, line 2; column 4, lines 7-47; column 7, line 43 column 8, line 4; examples 5,6,10,12,13; column 11, lines 36-43; claims 1-4, 8,20-24,29 Form PCT ISA:210 (extra sheet) (Jakuary IMa) international Application No, PCT/GB 89/ 0530 FURTHER INFORMATION CONTINUED FROM THE SECOND SHEET OBSERVATIONS WHERE CERTAIN CLAIMS WERE FOUND UNSEARCHABLE 1 This international search report has not been established In respect of certain claims under Article 17(2) for the following reasons: Claim because they relate to subject matter not required to be searched by this Authority, namely: 2. Claim because they relate to parts of the International application that do not comply with the prescribed require- ments to such an extent that no meaningful International search can be carried out. specifically: 3[D Clim because they are dependent claims and re not drafted In accordance with the second and third sentnces of PCT Ruie 6.4(s). VI.] OBSERVATIONS WHERE UNITY OF INVENTION IS LACKING This International Searching Authority found multiple Inventions In this International application as follows: 1. claims 1 6, 16 19, 21 23 6. claims 13 2. claims 7, 8 7. claims 3. claims 9 8. claims 24 4. claims claims 11, 12 As all required additional search fees were timely paid by the applicant, this International search report covers all searchable claims of the International application. As only some of the required additional search fees were timely paid by the applicant, this International search report covers only those claims of the International application for which fes were paid, specifically claims: No required additional search fees were timely paid by the appllcant. Consequently, this International search report is restricted to the invention first mentioned In the claims; it sl covered by claim numbers: As all aearchableclaims could be searched without effort Justifying an additional fee, the Intemational Searching Authority did not invite payment of any additional fee. Remark on Protest The additional search fais were accompanied by applicant's protest SNo protest accompanied the payment of additional search feea. Form PCT/ISAt210 (supplemental sheet (January 195) ANNEX TO THE INTERNATIONAL SEARCH REPORT ON INTERNATIONAL PATENT APPLICATION NO. GB 8900530 SA 28790 This annex lists the patent family members relating to the patent documents cited in the above-mentioned international search report. The members are as contained in the European Patent Office EDP file on 19/12/89 The European Patent Office is in no way liable for these particulars which are merely given for the purpose of information. Patent document Publication FPatent family Publication cited in search report date .member(s) date US-A- 3779920 18-12-73 CA-A- 974225 09-09-75 GB-A- 1375242 27-11-74 FR-A- 1577581 08-08-69 CH-A 496107 15-09-70 DE-A- 1771839 02-03-72 GB-A- 1209919 21-10-70 NL-A- 6810310 23-01-69 US-A- 3720616 13-03-73 WO-A- 8705926 08-10-87 US-A- 4784782 15-11-88 AU-A- 7205587 20-10-87 EP-A- 0333705 27-09-89 JP-T- 63502906 27-10-88 EP-A- 0098717 18-01-84 JP-A- 58225196 27-12-83 US-A- 4513155 23-04-85 EP-A- 0168534 22-01-86 JP-A- 60229994 15-11-85 EP-A- 0103737 28-03-84 DE-A- 3232921 08-03-84 CA-A- 1200373 11-02-86 US-A- 4517114 14-05-85 US-A- 4295861 20-10-81 None US-A- 2030033 None EP-A- 0069507 12-01-83 US-A- 4367152 04-01-83 CA-A- 1172237 07-08-84 JP-A- 58023892 12-02-83 OE-A- 3131950 25-03-82 None US-A- 3078228 None US-A- 4075111 21-02-78 None US-A- 3939084 17-02-76 BE-A- 696664 05-10-67 DE-A- 1644909 19-05-71 Cor more dl abu hi O P w For more details about this annex see Official Journal of the European Patent Office, No. 12(82 I I I ANNEX TO THE INTERNATIONAL SEARCH REPORT ON INTERNATIONAL PATENT APPLICATION NO. Page 2 GB 8900530 SA 28790 This annex liststhe patent family members relating to the patent documents cited in the above-mentioned international search report. The members are as contained in the European Patent Office EDP file on 19/12/89 The European Patent Office is in no way liable for these particulars which are merely given for the purpose of information. Patent document Publication Patent family Publication cited in search report date member(s) date US-A- 3939084 FR-A- 1517601 GB-A- 1188813 GB-A- 1192910 NL-A- 6704601 US-A- 3591500 US-A- 3752764 US-A- 3759829 US-A- 3788992 22-04-70 28-05-70 09-10-67 06-07-71 14-08-73 18-09-73 29-01-74 FR-A- 2249879 30-05-75 None S. w For more details about this annex :see Official Journal of the European Patent Office, No. 12/82