This invention relates to a new composition, and the use of such a composition to inhibit the corrosion of metals, especial ly when incorporated into oi Is and greases, and thus to a process which comprises treating least part of the surface of a metal with the composition, a metal coated with the composition, and a lubricant composition comprising the composition and an oi I or a grease.

In our publ i shed European Patent App I i cat i on No 247728

" ^υ there is disclosed a composition comprising an optional ly substituted hydroxyoxime and an anhydride containing a long alkyl chain. The composition may be incorporated into an oi I for the protection of metal surfaces against corrosion, and under most conditions, the composition provides extremely good

\'5 protection of the metal surface against corrosion. However, when moisture is present the efficacy of the composition can be severely impaired, and the βnt i -corrosi ve properties imparted to the metal surface can be unacceptable.

The composition disclosed in EP 247728 can also be 0 incorporated in to greases for the lubrication of metal surfaces which are in sl iding or frictional contact. In most instances such grease formulations provide excel lent antiwear characteristics on those metal surfaces. However _^ in the presence of moisture, the grease has been found to destructure 25 under certain circumstances and the lubricating characteristic of the grease is lost thus resulting in greater wear and/or corrosion of ^ he metal surfaces.

We have now found that improved corrosion inhibition and greater resistance to moisture can be obtained u ing a mixture

30 of a hydroxyoxime compound together with the reaction product of a substituted cycl ic anhydride and an organic moiety containing ami no and/or hydroxyl groups.

35

That such compositions have been found effective is surprising, since in most cases the individual components of the composition have been found to exhibit I ittle, if any, ant i -corros i on properties, when incorporated into to an oi l and app I i ed to a metal surface.

According to the present invention, there is provided a compos i t i on compr i s i ng a) a surface—act i ve anhydride derivative of the general formu I a I

X-Y-(Z), (I )

where i n

X represents a saturated or unsaturated hydrocarbon group containing from 8 to 500 carbon atoms;

Y represents a succinic anhydride residue or an aromatic anhydride residue carried terminal ly on the group X; each Z independently represents an organic group carrying an oxygen, sulphur or nitrogen atom through which it is I inked to Y; m i s 1 or 2 ; and b) a hydroxyoxime.

The group X is preferably a saturated or unsaturated aI iphatic hydrocarbon chain which has a molecular weight of from about 100 to about 8000 and especial ly from about 100 to about 2000. Thus, the group X preferably contains at least 8 carbon atoms and up to about 150 carbon atoms and can be

I inear or branched. Examples of such groups are nony I , decy I , deceny I , dodecy I , dodeceny I , hexadecy I , octadecy I , octadeceny I and long alkyl chains such as those obtained for example by the polymerisation or copo I ymer i sat i on of mono-olefins containing from 1 to 6 carbon atoms, for example, ethylene, propylene, but-1-ene, but-2-ene or isobutylene.

Preferred groups X are those derived from the polymerisation of isobutylene. These polymers can be made by standard methods and are commonly referred to as alk(en)yl po I ymers.

Such polymers have a terminal double bond that can be reacted with a I e i c anhydride to form alk(en)yl substituted succinic anhydride derivatives by reaction in the presence of a standard condensation catalyst for example a halogen such as bromine, to form a compound of formula II

and such compounds are those which are used in the compositions of EP 247728. The alk(en)yl substituted succinic anhydrides of formula

II are commercial ly readi ly avai lable and can be used in the form in which they are avai lable without further purification.

PoI yisobuty I ene succinic anhydride is commonly refer -ed to as

PIBSA. A preferred compound of formula II, is a po I y < i sobuteny I )succ i ni c anhydride and particularly one with a number average molecular weight of up to 5000.

When the group Y is an aroma ic anhydride residue, it is preferably derived from phthal ic anhydride, and especial ly phthal ic anhydride wherein the group X is attached in the

4-ρosition relative to the anhydride group. It is preferred, however, that the group Y is a succinic anhydride residue derivable from the succinic anhydride group

shown in formula II.

When Y is such a group it is preferably a di- or trivalent group of the formula

CH - CH. o r - CH - CH. o r - CH - CH.

CO CO CO CO CO CO

OH OH

I inking the group X to one or two groups Z.

The group Z in the compound of formula (I) is preferably the residue of an organic compound containing at least one amino or hydroxyl or thiol group and containing up to 20 carbons, more preferably up to 12 carbon atoms and especial ly up to ό carbon atoms. The group Z is preferably an optional ly substituted alkyl group, which may be l inear or branched, but is preferably l inear and preferably carries up to a total of 6 amino and/or hydroxyl groups, more preferably from 2 to 4 amino and/or hydroxyl groups, and especial ly 2 or 3 amino and/or hydroxyl groups. Where the group Z is I inked to Y through nitrogen amino this is preferably the nitrogen atom of an amino group which may be primary or secondary but is preferably a primary amino group. It is especial ly preferred that the organic group contains both an amino group and a hydroxyl group through either of which it may be joined to Y.

The group Z may contain other groups in addition to the amino and/or hydroxyl and/or thiol groups such as carboxy I ic aci d groups .

The group Z is preferably derived from an alcohol or a polyol , for example it may be derived from ethylene g I yco I , propy I ene g I ycoI , glycerol , tr imethy IoI propane, penta- erythritol or sorbitol .

The group Z may be derived from an amine or polyamine for example ethy I ened i ami ne, tr imethy I ened i ami ne , hexamethy I ened i ami ne , tetraethy I enepentami ne , d imethy I ami no- propylamine or d i ethy Iami no- propy lamine.

However, the group Z is preferably derived from an organic compound containing both amino and hydroxyl groups such as monoethano I ami ne , d i ethano Ia i ne, d i propanoI ami ne, tr i s(hydroxymethy I )ami nomethane or d imethy I ami noethanoI . The group Z may also be derived from an organic compound containing other groups such as a carboxy l ie acid group in addition to the amino and/or hydroxyl group, for example glycine or gI ycoI I i c acid. In practice the compounds of formula (I) are obtained as a mixture of isomers.

For example, those derived from poI y i sobuty Iene and maI e ic anhydride have the fol lowing major components:—

or

where i n _n has an approximate value of from 2 to 100 such that the compound has a molecular weight from about 200 to 5000 and

Z is as hereinbefore defined and is I inked to the CO group through an oxygen nitrogen or sulphur atom.

The compounds of formula (I) are readi ly prepared by reacting the appropriate alk(en)yl succinic anhydride with the appropriate organic amino or alcohol compound at a temperature of from 70 to 150 ^* C in an inert solvent or di luent, for example, xy I ene . Reaction is continued unt i I a substantial ly constant acid value is achieved. Preferably, the reagents are used in substantial ly equimolar proportions based on the anhydride ring and the hydroxyl and/or amino groups.

Thus they produce a half derivative of the succinic group having a free carboxy I ic acid group obtained by the opening of the anhydride ring, as shown in formulae III and IV.

Excess amounts of the organic moiety represented by Z may be used to react with the alk(en)yl anhydride such that the surface active anhydride derivative of general formula I contains no free carboxy I i c acid groups.

However, it is preferred that the compound of general formula I contains one free carboxy I ic acid group, and it is especial ly preferred that n is 1.

The preferred anhydrides are succinic anhydrides where the group X is an isobutylene polymer of molecular weight from about 100 to 8000, and espe al ly from 600 to 6000 and more especial ly from 800 to 1200.

A preferred example of the compounds of general formula I is the reaction product of polyisobutenyl succinic anhydride having a molecular weight of approximately 1100 and ethano I ami ne .

The hydroxyoxime which is component (b) of the composition in accordance with the present invention is preferably an aromatic hydroxyoxime of the formula

N-0H

wherein A is an aromatic system, especial ly a benzene ring; and R ¹ is a hydrogen atom or a substituted or unsubst i tuted hydrocarbon group. The hydroxyoxime is more preferably a hydroxy monooxime of the formula V or hydroxy bi-soxime of formu I a

wher in R ¹ is as hereinbefore defined; and

R ² is a substituted or unsubst i tuted C5-22 hydrocarbon group.

The group R ¹ is preferably hydrogen but may be an alkyl , ary I or benzyl group, which may be substituted. When R ¹ is aryl , it is preferably pheny I , and when R\' is alkyl , it is preferably C1-4 alkyl , for example methyl. In the bis—oxime compound of formula VI, the second oxime group is preferably in the 6-pos i t i on (ie ortho to the hydroxyl group) and especial ly preferred compounds of this type are the 2 ,6—b i s(ox imi nomethy I )—4-a I ky I phenoI s .

The group R ² is preferably a C5-14 alkyl group which may be I inear or branched and may be saturated or unsaturated, but is preferably saturated. The group R ² is preferably in the para position with respect to the phenol ic hydroxyl group when the compound is a 2—hydroxy—5-a I ky I benza I dox ime or 2-hydroxy-5—a I ky I benzoketox ime. Examples of the group R ² include decy I , deceny I , dodecy I , dσdeceny I , hexadecy I , octadeceny I and especial ly nony I . Specific examples of the hydroxyoxime compounds are 2-hydroxy-5-nony I benza I dox ime, 2-hydroxy-5-dodecy I benzaI dox ime and 2-hydroxy-5-nony Iaceto- phenoneox ime. The weight ratio of the surface active anhydride derivative of general formula I to the hydroxyoxime may be between 99: 1 to 1:99 but wi l l general ly be from 10:1 to 1: 10, particularly from 5:1 to 1:5. However, the .preferred proportions wi I I be dependent on the particular compounds present in the mixture.

The compositions of the present invention provide improved corrosion inhibition in corrodible metals and certain of the compo itions also provide improved anti-wear properties and/or improved ant i-oxidat ion properties. Thus, as a further aspect of the present invention, there is provided a process which comprises treating at least part of the surface of a metal with a composition colmprising (a) a surface active anhydride derivative of general formula I , and

(b) a hydroxyoxime, as hereinbefore defined.

The process of the present invention is especial ly suitable for the corrosion inhibition of iron, zinc, copper, tin and al minium and in particular mi ld steel and the zinc surface of galvanised steel .

The metal may be treated directly with the composition.

However it is general ly preferred to apply the composition to the metal surface in the form of a solution in a suitable organic l iquid or as an aqueous emulsion or dispersion of the composition or as an aqueous emulsion of a solution of the composition in an organic l iquid.

The composition may be used to provide a protective coating in its own right, or as a metal pre—treatment before the app I i cat i on of a surface coating, or may be incorporated into a surface coating composition, or may be employed as an additive to refined petroleum products such as lubricating oi ls, turbine oi ls, fuel oi ls, gasoho I s and greases. Any suitable organic I iquid may be used as a solvent for the composition, such as al iphatic and aromatic hydrocarbons, and their halogenated derivatives, ethers and ketones. Especial ly preferred solvents are those having goodL wetting and drying properties and include for example benzene, toluene, xy I ene , kerosene, white spirit, chloroform, and 1 , 1 , 1-trichl oroethane .

Aqueous emulsions of the composition may be formed in conventional manner using conventional dispersants and surfactants, including non- i on i c dispersants. It may be convenient to treat the metal with an aqueous emulsion of the composition, particularly if the anhydride present in the composition is a l iquid which can be formed directly into an emulsion.

The process of the present invention may provide corrosion inhibition either without the appl ication of a further surface coating or as a pre-treatment before the appl ication of a further surface coating. Thus, the treatment may be used for example as a temporary protection of a metal , for example wh i le the metal is being transferred from one site to another and the protective coating subsequently removed before or during further processing.

Alternatively, the composition may be formulated in a surface coating composition, for example a paint (primer) such as air—drying, oi I—modi f ied system or a system including a chlorinated rubber, lacquer, resin or other protective coat i ng .

The surface coating may be a so I vent—based composition, for example a eel I u Iose/soIvent based primer paint such as those used for car "touch up" paints.

The components of the composition are soluble in solvents general ly used for such primers (for exam le nitrocel lulose) and may be incorporated directly. The composition may also be used as an emulsion in aqueous emulsion surface coating systems, for example primers or protective coatings based on polymer latices such as for example acryl ic and styrene/acry I ic latices and v i nyj_ acryl ic cc-polymer latices including acrylate modified vinyl chloride v i ny I i ene chloride copolymer latices.

The composition may also for example be incorporated in temporary a I ka I i-removab Ie protective coatings (whether solvent-based or em lsion based) of the addition polymer type in which the polymer contains carboxyl groups. The composition or the solution or emulsion thereof may be app I i ed to the metal in conventional manner, for example by dipping, spraying or brushing. The temperature of the app I i cat i on may be from 0 to 50*C.

Typical ly, solutions of the composition may contain from 0.1 to 20% by weight of the mixture of the anhydride derivative and the hydroxyoxime, whi lst emulsions preferably contain from 0.1 to 5% by. weight of the mixture of anhydride

-> derivative and hydroxyoxime.

The presence of from 0.1 to 2% by weight of the mixture of anhydride derivative and hydroxyoxime in a surface coating emulsion formulation is general ly sufficient to provide improved corrosion inhibition.

\'0 If the compo ition contains materials in addition to the anhydride derivative and the hydroxyoxime, the amount of the composition which is used should be sufficient to provide the mixture of the anhydride derivative and the hydroxyoxime in the proportions as set out herein.

15 The metal to be treated may be brightly po I ished and/or freshly cleaned, but it is an advantageous feature of the process of the present invention -that effectiv-e corrosion inhibition may be obtained even on a l ightly rusted surface. Indeed we have found that better results are in general

20 achieved when a surf a is treated in an "as received" condition than when that same surface is freshly cleaned or brightly pol ished.

The present composition has been found to g i v.g_ greatly improved protection of metal surface against wear and

25 corrosion in tank oi l systems and greases which ar e subject to contact with water.

Thus, according to a further aspect of the present invention there is provided a lubricant composition comprising a ⁾ a surface active anhydride derivative of the formula I

30

X-Y-(Z)„ (I )

, wherein X, Y, Z and m are as hereinbefore defined; b) a hydroxyoxime; and 35 c) an oi I or a grease;

The oi I is preferably a mineral oi I or a synthetic oi I such as a po I ya I ky I ene glycol , a po I ya I pha olef in, an ester and in particular a phthalate, a perf I uoroa I ky I ether or a s i I i cone .

The greases are preferably mineral or synthetic oi Is which have been thickened by the addition of gel I i ng agents.

Typical ly, the mineral oi l is a hydrocarbon oi I , and the synthetic oi I may be for example a synthetic hydrocarbon oi I , a diester such as d i (2—ethy I hexy I )sebacate, a perf I uoroa I ky I ether or a si I i cone oi l .

Many greases are obtained using soaps as the gel I i ng agent, especial ly I ithium soaps. However, non-soap gel I i ng agents can produce a grease having improved properties, especial ly the clarity to remain effective at higher use temperatures. Examples of non—soap gel I i ng agents present in such greases are clays, carbon black, si I ica and polyurea al I of which are preferably incorporated into the oi I as finely divided sol id materials.

Finely divided clay particles, for example clays of the bentonite or hector ite types can be used as non—soap gel I i ng agents to obtain a grease from a mineral oi l . Preferably, the clay particles are surface-coated with an organic material such as a quaternary ammonium compound.

Where the grease is based on a si I icone oi 1 , the non-soap gel I ing agent is preferably si I ica, and especial ly fused si l ica having an average particle size less than one mi cron.

The lubricant composition preferably contains from 0.1 to 30% by weight of the hydroxyoxime relative to the total volume thereof and more preferably from 0.1 to 5%.

In addition to the hydroxyoxime and anhydride derivative, the lubricant composition may include various other ingredients commonly incorporated into such compositions such as oxidation inhibitors, and extreme pressure additives.

The lubricant composition may be prepared using any of the techniques which are effective for incorporating additives into oi I or grease media.

For example a grease composition may be formed by stirring together the thickened grease with a composition containing the anhydride derivative and the hydroxyoxime.

As an alternative, the composition of the anhydride derivative and the hydroxyoxime may be incorporated into an oi I which is subsequently thickened to form a grease. The lubricant composition in which component (c) is a grease may be used in any app I ication for which a grease is known, and in particular can be used in general automotive appl ications and also in bearings including high performance bear i ngs . We have found that when subjected to an anti—rust test the present lubricant composition shown improved resistance to corrosion and destructur i ng compared to a grease containing the composition disclosed in EP 247728.

A bearing containing, a lubricant composition in accordance with the present invention is a further feature of the present invention.

The compositions of the invention may also include other materials, particularly materials which also provide corrosion inhibiting properties. Such corrosion inhibiting materials include, for example, petroleum sulphonates, aryI sulphonates and the metal salts thereof.

The other materials may be present in the composition in a substantial proportion of up to several times, for example up to ten times, by weight of the composi ion of the anhydride and the hydroxyoxime.

In general no particular advantage is achieved by using a large excess of the other materials and preferably the proportion of the other materials do not exceed twice the weight of the composition and conveniently the other materials are present in essential ly an equal proportion by weight relative to the weight of the composition.

Various aspects of the present invention are set out in more deta i I hereafter in the fol lowing i I lustrative examples in which al I parts and percentages are by weight unless

O otherwise stated.

Examp I e 1

Samples of a so I vent—neutra I mineral oi I , containing

0.1% corrosion inhibitor and a sample of the sample oi l

\'5 containing no additive were subjected to an oi l/water corrosion test based on ASTMD όό5B modified as set out hereafter .

The test involves stirring a mixture of the oi l (300 ml .) and synthetic sea water (30 ml .) for 24 hours at 0 1000 rpm and at a temperature of 60*C containing a completely immersed and previously weighed cyl indrical steel specimen.

The metal specimen is then removed, cleaned, re—weighed to determine weight loss (if any) and examined for evj_dence of corros i on. 5 The results obtained are set out in Table One.

30

35

TABLE ONE

Notes to Table One (a) BAO is 2-hydroxy-5-nony I benza I dox ime

PMEA is a reaction product of po I y i sobuteny I succ i ni c anhydride of approximate molecular wei-ght 1100 and monoethano I ami ne.

Examp I e 2

Samples of a l ithium complex grease containing 2% corrosion inhibitor and also a sample of the same grease containing no additive were subjected to a modified ASTM D1831 (Rol l Stabi l ity of lubricating grease) test as described here i nafter .

A sample of l ithium complex grease (90 parts) containing 2% corrosion inhibitor and disti l led water (10 parts) were placed in a test cyl inder.

The grease was distributed evenly over the insi e wal l of the cyl inder, a /eighted rol l was placed in the cyl inder and the cap tight _\' , je . The cyl inder was then rol led at 165 + 15 rpm for two hours after which the grease removed and subjected to the cone penetration test for lubricating greases .

This was carried out using one—ha I f scale cone equipment and the procedure of ASTM D1403. The cone penetrations were carried out on samples of grease which had been brought to 25 ^* C and subjected to sixty double strokes in a grease worker in the manner described in ASTM D1403. Using the standard formula as set out in ASTM D1403, the measurements made were transformed to give the work penetration of the cone for fu I I scale cone equipment.

The results obtained are set out in Table Two.

TABLE TWO

Examp I e or Worked Comp . Ex Penetrat ion (b)

311

destructured 300

Notes to Table Two

(a) BAO is 2-hydroxy-5-nony I benza I dox ime PMEA is a reaction product of po I y i sobuteny I succi ni c anhydride of approximate molecular weight 1100 and monoethano I ami ne

TPSA is tetrapropeny I succ i n i c anhydride.

(b) measured tenths of a mi I I imetre.