CA2196597A1

CA2196597A1 - Improvements in oleaginous active sulphur-containing compositions

Info

Publication number: CA2196597A1
Application number: CA002196597A
Authority: CA
Inventors: Dale Robert Carroll; Brid Dilworth; Michele Anne Thornhill
Original assignee: Individual
Current assignee: ExxonMobil Chemical Patents Inc
Priority date: 1994-08-01
Filing date: 1995-07-31
Publication date: 1996-02-15
Also published as: WO1996004355A1; GB9415623D0; AU3255095A; JP2000510498A; AU683406B2; EP0775187A1

Abstract

The compatibility with nitrile elastomer seals of lubricating compositions containing active sulphur-containing additives may be enhanced by treating the additives, or concentrates containing them, or the compositions themselves, with one or more olefinically unsaturated compounds selected from: (a) acyclic compounds having at least two double bonds with adjacent double bonds separated by two satured carbon atoms; (b) compounds containing an alicyclic ring, which ring contains at least, eight carbon atoms and at least two double bonds, each double bond being separated from the closest adjacent double bond(s) by two saturated carbon atoms; and (c) compounds containing a saturated alicyclic ring and at least one exocyclic double bond.

Description

2l q6597 IN OLEAGINOUS ACTIVE SULPHUR-CONTAINING COMPOSITIONS

The invention is concerned with improving the longterm reliability of ela~lu,"eNc seals, and is ~,o"ce~ "ed in particular with enabling nitrile seals in engines to meet the stringent requirements arising from modern engine design and operating co".liliu,ls, and en~,i,ul""e"Lal conside,dliul-s.

Power trains, for example, automotive power trains, require shaft and bearing seals to prevent lubricants leaking out and to prevent the ingress of cullldlllilldlll~. Seal iife depends on, inter alia, the suitability of the chosen seal for the use to which it is put, the degree of care used in installing the seal, the temperatures to which the seal is exposed in use, the nature of the lubricants with which the seal comes into contact, and the condition of the surface(s) with which the seal comes into contact during use. Seal failure will in most cases lead to leakage of lubricants, which is i".,, uasi~ Iyly regarded as u"~r.cel N~Mle, and seals which can no longer perform their intended function must normally be replaced.
There is thus a need for the life of seals to be prolonged for as long as possible.

el 1 IdliUI ,al Spe.;ir,ccliull No. WO 85/û4896 indicates that labile sulphur-free additives for lubricants can be obtained by treating additives cu, Itdil lil ,g labile sulphur with copper, or copper and another material reactive with labile sulphur, or with an olefin, particularly an a-olefin, a-olefins co"ldil ,i"g 4 to 30 carbon atoms, especially 10 to 2û carbon atoms, being preferred. The olefins ,,,t:,,liuned in the Examples are all C1s-18 or C16-18 a-~lefinS

C1s 18 a-olefins are also the preferred compounds for use in the process described in U.S. Patent No. 4 228 022. More generally, it is indicated that theolefins preferably contain 10 to 3û carbon atoms, especially 15 to 2û carbon atoms, and may be straight chain or branched.

European Specification No. 151 581 B is concerned with the ,u, I::pdl dliOn of lubricating oil additives which have sufficiently low levels of active sulphur to ensure that lubricants co, lldil ,il ,g the additives are non-staining and non-corrosive to copper and similar materials. Ole,finically unsaturated compounds co, lidil lil l9 8 to 36 carbon atoms are used. The olefinically unsaturated compounds are compounds cu, ILdil lil l9 one or more non-aromatic double bonds, and may be 21 9~597 W0 96/04355 - 2 - r ~

Iinear or alicyclic. ~-Olefins are preferred, particularly C16 1 g a-olefins, although other types of olefinically unsaturated compounds are referred to.

The reaction of a sulphurized substance with an olefin to reduce the corrosivity of the product is also disclosed in U.S. Patent No. 4 147 640, which is ~ concerned with the pl C:pdl d~ic11 of lubricating oil antioxidant additives which are free from metals and phosphorus, and which have the ability to protect copper-lead bearings from corrosion. The olefins used contain about 6 to 18 carbon atoms and 1 to 3 olefinic double bonds. The preferred compounds are c~,clu,ue, ,Ladie,1e dimers and ~ "~ne.

Other crerifi~.~tions which disclose lubricating oil compositions containing, among other things, oil-soluble sulphur-containing organic compounds are Il llul l ldliolldl Speciricdliol~s Nos. WO 86/04601, WO 86/04602, WO 86/03772 and WO 86/02638, and U.S. Patent No. 4 664 825. All five of these ~l ,e~ ;ri, ~l ;u, 15 refer to the possibility of reducing the active or unreacted sulphur content of sulphurized organic compounds by treating the compounds with an alkali metal sulphide. The :~,ue-,iril.dlions also indicate that the cu~posilions disclosed show good nitrile seal cu,,, "' :' 'y.

The applicants have now discovered that the life of nitrile elastomer seals can be ,iylliri~.d,~iy enhanced, when lubricating .,u,,,po~i~iuns in contactwith such seals contain active sulphur, by the inclusion in the culll,uus;liul 15 of certain ole~i"ica"y unsaturated compounds. By "active" sulphur is meant sulphur, including elemental sulphur, which attacks nitrile eld:.lu,,,c,,~.

Whilst the problems of seal culllpdliuility and copper corrosion have been add, u:,sed by the prior art in relation to sulphur-~u"Ldi"i"g additives, there is still a need for improved or alternative products or processes for improving cu",, "b:' 'y of such additives with t~la~lu" ,el ic seals, in particular nitrile seals. The problem of seal cu",r "b:" y seriously impairs the utility of sulphur-containing additives in lubricating oil .,ulll,uosiliuns which come into contact with nitrile seals.

The applicants have surprisingly found that the use of certain selected ., oldri"ical'y unsaturated compounds to treat an active sulphur-cu, ~Idil liu g lubricating oil additive, cul l~eull dl~, or ~,u~ JosiLiul l can bring about a particulariy ~marked e"l,~"ce",enL in the life of nitrile elastomer seals. The invention is of 2~ 96597 ~,vo s6/043ss - 3 - P~~ . r~n~,~

particular use for lubricants, such as lubricants for heavy duty diesel engines which normally contain a relatively high level of sulphur-,.o, ILdi~ 1;119 substances.

The present invention provides a lubricating COlll,uOaiLion ObLdilldL~Ie by mixing:

(1 ) a major p, upo, liol, of lubricating oil;

(2) an oil-soluble active sulphur-co, ILdil lil l9 additive, and (3) an oil-soluble oleflnically unsaturated compound selected from:
(a) acyclic compounds having at least two double bonds, adjacent double bonds being separated by two saturated carbon atoms;
(b) compounds co, ILdil lil l9 an alicyclic ring, which ring contains at least eight carbon atoms and at least two double bonds, each double bond being separated from the closest adjacent double bond(s) by two saturated carbon atoms; and (c) compounds co, ILdil lil ,g a saturated alicyclic ring and at least one exocylic double bond.

The invention also provides a treatment method which culll~uliaes treating an active sulphur-cu"ldi"i"g lubricating oil additive, conce"L,aL~, or CullluOaiL
with an olefinically unsaturated compound as specified in the preceding pdl dUI dj~l 1.

The invention further provides the use of an ole:~i"i.,al!y unsaturated compound selected from (a), (b) and (c) above to increase the nitrile elastomer colllr_~ / ."y of a lubricating cu",uo~iLion CUllLdillillg sulphur and/or a sulphur-Cul ILdil lil Iy compound having a deleterious effect on the elastomer. For example, an olefinically unsaturated compound selected from (a), (b) and (c) above may beused to reduce the tendency of a nitrile elastomer to be degraded by a lubricating cU~,uosiLiOIl COI ILdil lil l9 sulphur and/or a sulphur-co, ILdil lil)9 compound, and may thus be used to enhance the life of an engine seal in contact with such a c~",,uosiLiù,~.

Sulphur-co, ILail lil l9 additives are widely used in lubricating co",uosiLions as, for example, oxidation inhibitors, extreme pressure and antiwear agents, and/or load-carrying additives, commonly used classes of sulphur-co, ILdil ,i"g 21 ~65q7 W096104355 -4- r~ )C6 additives being sulphurized phenols, sulphurized olefins, and salts of phosphorus-and/or sulphur-containing acids, for example, phos~hu, udill ,ioic acids and '-" liOCdl bdllliC acids, although the invention is not confined to these particular classes of additives. Such additives may be used in lubricants, for example, crankcase lubricating oils, gear lubricants and metalworking lubricants, including various functional fluids, for example, hydraulic fluids, automatic L, dl l:~lllis5kJI I
fluids and heat transfer fluids.

Sulphurized phenols include mono-, di- and polysulphides of phenols or alkyl phenols, salts thereof, and overbased salts thereof. The alkyl phenols maycontain one or more alkyl groups per aromatic ring. Typical sulphurized alkyl phenols for use as lubricating oil additives may be, ~p,~st:"led by the formula (R)p (R)p (R)p ~ Sx~ x ll~

OH OH OH

wherein R, ~,u,~sel ,L~ an alkyl radical, n is û or an integer of from 1 to 4, p is an integer of from 1 to 3, and x is an integer of from 1 to 4, the average number of carbon atoms in the alkyl group(s) being sufficient to ensure adequate solubility in oil. The individual groups, ~,u,~ser,Led by R typically contain from 5 to 4û, preferably 8 to 2û,'carbon atoms. Metal salts of sulphurized phenols may be obtained by reacting an alkyl phenol sulphide with a sufficient quantity of metal-Cl:n ILdil lil ~g material, for example, a metal oxide or hydroxide, to obtain a neutral or, if desired, overbased sulphurized metal phenate.' Processes for preparing overbased metal phenates are well known in the art, and do not need to be described further here.

Examples of sulphurized olefins, and other olefinically- unsaturated compounds, which may be used in lubricating co",posiLiu"s are given in the priorart referred to earlier in this specihcation for example, l, IL~I I ,dLional ~Sr~ iri~"~l;ons Nos. WO 86/04601 and WO 86/02638 and U.S. Patent No. 4 664 82~.

Salts of p hosphol udithioic acids include metal dihydrocarbyl uiU liOpllOa,ullaLt:s, for example, zinc dihydrocarbyl diU liupho~l-l ,dLes (ZDDPs).

0 96/04355 - 5 - F~1/E;I ~/03~

Especially preferred ZDDPs for use in oil-based cu"~,uosiLiu~ IS are those of the formula Zn[SP(S)(OR1 )(OR2)]2 wherein R1 and R2 contain from 1 to 18, and preferably 2 to 12, carbon atoms. Particularly preferred as R1 and R2 radicals are alkyl radicals having 2 to 8 carbon atoms. Examples of radicals which R1 and R2 may represent are ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, amyl, n-hexyl, i-hexyl, n-heptyl, n-octyl, decyl, dodecyl, octadecyl, 2-ethylhexyl, phenyl, butylphenyl, cyclohexyl, methylcyclopentyl, propenyl and butenyl radicals.

Salts of dill liOCdl L,a",ic acids typically have the formula [RR'NC(S)S]nM, wherein R and R' represent the same or different hydrocarbyl radicals co, ILdil lil 19 1 to 18, preferably 2 to 12 carbon atoms, for example, alkyl, alkenyl, aryl, aralkyl, alkaryl or cycloalkyl radicals. M may represent any suitable metal, for example molybdenum, zinc, or copper. Preferred dillliocalLIdllldL~s for use in lubricating oil co",,uo~ilions are those CUI lldil lil l9 2 to 12 carbon atoms.

The sulphur-cr., lldi~ g lubricating oil additives discussed above, and many other sulphur-co, lldil lil Ig lubricating oil additives, are typically prepared by ,ul ucesses in which a starting compound is reacted with sulphur and/or a sulphur-CCII Itdil lil Ig compound, for example, hydrogen sulphide or sulphum l lul1oh~ ' ' or dihalide. The sulphurized products, which will normally comprise a mixture of different compounds, typically contain at least some sulphur which is either free, or is only loosely bonded, the sulphur thus being available to attack nitrile eld~lulllela. as indicated earlier, sulphurwhich attacks nitrile eldalu",e,:, isreferred to herein as "active sulphur".

A lubricant for a heavy duty diesel engine will typically contain from O to 3 mass ~/O of a sulphur-containing compound such as a sulphurized alkyl phenol.

In acco, ddl ,ce with the invention, an active sulphur-co, ILdil lil ~g additive for a lubricating co,,,juosiliul ,~ the cu,,,,uosilio~1 itself, or, preferably, a co"ce"L,dLe for forming a lubricating composition containing such an additive, is treated with an oil-soluble ol~ril ,i~,allj unsaturated compound selected from:

(a) acyclic compounds having at least two double bonds, adjacent double bonds being separated by iwo saturated carbon atoms;

(b) compounds co, ILdil lil l9 an alicyclic ring, which ring contains at least eight carbon atoms and at least two double bonds, each double bond being 21 965~7 WO 96/04355 , ~.111~1 ~ -' ~

separated from the closest adjacent double bond(s) by two saturated carbon atoms; and (c) compounds containing a saturated alicyclic ring and at least one exocylic double bond.

More than one olefinically unsaturated compound selected from (a), (b) and ~c) above may of course be used if desired. Where two or more compounds are used, these need not be compounds from the same group. Thus, for example, a compound selected from (a) may be used with a compound selected from (b) or (c) .

Preferred compounds of group (a) are unsl Ihstit, Ited or sl Ih5ti~l It.~d linear terpenes. Uns~ Ihctit~ It~d linear terpenes for use in a~-:ul ddl l~,e with the invention may be I t~ll e5el IL~d by the formula (CsHg)n wherein n is at least 2, that is, a terpene co, lldil lil ~g carbon and hydrogen atoms only. A preferred unsl Ih5tih ~t~d linear terpene for use in acco, dallce with the present invention is squalene (in which n in the above formula is 6). Possible substituents for linear terpenes to be used in dacco"~ance with the invention are, for example, hydroxyl groups.

Preferred sl Ihstitl It.~d terpenes include geraniol and farnesol.

A preferred group (b) compound having two double bonds only is 1 ,5-cyclooctadiene. 1~ desired, the group (b) compound may contain at least three double bonds, each end of each double bond being separated from each adjacent double bond by two saturated carbon atoms. A preferred group (b) compound having three double bonds is 1,~,9-cyclodorl~,: ~Mene.

The compounds of group (c) are compounds ~,ol Itdil lil l9 a saturated alicyclic ring and at least one exocyclic double bond. Advantageously, the exocyclic double bond, or one of the exocyclic double bonds, links a carbon atomin the said alicyclic ring and an exocyclic carbon atom. The alicyclic ring in the 6roup (c) compounds preferably contains at least six carbon atoms, and, advantageously, the alicyclic ring is sl Ihstitl Itpd by a methylene bridging group that forms a four-membered ring with three of the ring carbon atoms. The methylene carbon atom in such a bridging group may be sl Ihstitl ItPrl, preferably by two methyl groups. A particularly preferred group (c) compound is ,~-pinene.

2196~97 ~VO 96/04355 - 7 - I~

It is beiieved that the aliphatic double bonds in the compounds used in acco,dd"ce with the invention react with active sulphur in the additives, conce, ILI dL~s or oleaginous co" ,,uosilions treated with the compounds to "fix" the sulphur in a form in which it does not have a deleterious effect on nitrile seals, but the invention is not to be regarded as limited in any way by this u~,uldl IdLiol ,.

The compounds used in acco, I~dl ,ce with the invention are used in a proportion ap,ul upd dLt~ to the u~u,uo, liun of active sulphur in the additive,con~ "L,dL~, or oleaginous co"l,uosiliol1 to be treated, and the most dpUlUU~idLt:
proportion in any given case can be d~le""i"ed by routine ~ ,Ut~ 311L. In general, the use of 0.01 to 5 mass ~/0, advantageously 0.05 to 1 mass %, preferably 0.05 to 0.5 mass ~/0 of the olefinically unsaturated compound(s), based on the final lubricating oil CUlllpC~iLio~ I (includin9 the olehnically unsaturated compound(s)), may be d,Upl U,UI idLe, although in some cases, for example, wherethe colllposiLiu,, contains a relatively high proportion of active sulphur, the use of a somewhat higher proportion of the ol~ri, li.,..l!y unsaturated compound may bedesirable.

As indicated above, the olehnically unsaturated compound may be used to treat an active sulphur-cw ILdil lil l9 lubricating oil additive, or a lubricating oil cu" ,,uo~ilion (a cu"cu"l, dle or a hnished oil) ,,o, ILdil lil l9 such an additive.
Advantageously, however, the compound is used to treat a concu, lll dle which contains an active sulphur-co, ILdil lil l9 additive and, optionally, one or more other additives, and which may be blended with an oil of lubricating viscosity and, optionally, one or more other additive .,oncc:l ILI dL~s or additives, to form the final lubricating oil composition Other types of additive which may be present in a lubricating oil eulll,uosiLiol1, particularly a crankcase lubricating oil culll,uosiliull, or an additive col1ct:l lll dL~ which may be used for preparing such a co",po~ilion, include ashless dispersants, viscosity index modifiers, dt:lu,ye"l~, antiwear agents and dl lliUXiddl IL::I. Further details of these types of additives, and of uol1cul 11l dLt::~ and compositions uu~ ILdil lil ~g them, are given later in this . specification.

References in this specification to treating a first material with a second material are not to be understood as implying any particular order of mixing of the two materials. Thus, for example, the first material may be introduced into a vessel already containing the second material, or vice versa, or the two materials may be introduced simultaneously into the vessel.

2~ 59~

W0 96/04355 - 8 ~ 0~6 Treatment of an active sulphur-containing additive, ~,unct:l ,1, dle or lubricating oil composition with an ol~ri"ica:ly unsaturated compound used in aCCUI ddl ,ce with the invention may be carried out by mixing at ambient temperature, but is preferably carried out at an elevated temperature. Thus, forexample, where the olt,ril lic..:!y unsaturated compound is added to a cu, Ict:"l~ dlC:, the mixture is advantageously heated to a temperature of from 30 to 1 00~C, preferably 46 to 60~C, after addition of the ol~ri"ically unsaturated compounds,and is ",ai, ll~in~:d at that temperature, with stirring, for a period that can readily be del~""i"ed by the person skilled in the art.

Lubricating oil additives used or treated as described herein and the oleri"ica:ly unsaturated compounds used in ac..o, ddl Ice with the invention to treat additives, cu"~"~, dL~s or ~:u~uo~ ions are oil-soluble or (in common with certain of the other additives referred to below) are dissolvable in oil with the aid of a suitable solvent, or are stably di~u~l :,i ;,le materials. Oil-soluble, dissolvable, or stably d;~,ue,~ible as that l~lllli~lolo~y is used herein does not neceaad,ily indicate that the additives and compounds are soluble, dissolvable, miscible, or capable of being suspended in oil in all p, ul.o, liu"s. It does mean, however, that the additives and compounds are, for instance, soluble or stably ci;~,u~, ~iLle in oil to an extent suffjcient to exert their intended effect in the environment in which the oil is employed. Moreover, the additional i, ,cu, ,uu, d~ l of other additives may also permit i, ,.,u, uu, dliUI I of higher levels of a particular additive or compound, if desired.

Additives used or treated as described herein can be i"-,u, ,uo, dled into the oil in any convenient way. Thus, they can be added directly to~the oil by d;:,~ e, ~i"g or by dissolving them in the oil at the desired level of cu"cenl~ dliuns optionally with the aid of a suitable solvent such, for~example, as toluene, cycluh~i~dne, or tetrahydrofuran. In some cases blending may be effected at roomtemperature: in other cases elevated temperatures are advantageous.

Base oils with which the additives may be used include those suitable for use as crankcase lubricating oils for spark-ignited and cu",~Jrt~s~iu"-ignited internal combustion engines, for example, automobile and truck engines, marine and railroad diesel engines.

2 ~ 96597 ~,V0 96/0435~ - r - r~ . c/0~ 6 Synthetic base oils include alkyl esters of dicarboxylic acids, polyglycols and alcohols; poly-c~-olefins, polybutenes, alkyl benzenes organic esters of pho~,ulloric acids and polysilicone oils.

Natural base oils include mineral lubricating oils which may vary widely as to their crude source, for example, as to whether they are paraffinic, n d,uh;l ,enic, mixed, or parahnic-nd,ul ,ll ,e"i~., as well as to the method used in their production, for example distillation range, straight run or cracked, hydrofined, solvent extracted and the like.

More specihcally, natural lubricating oil base stocks which can be used may be straight mineral lubricating oil or distillates derived from paraffinic, na~ h Ihenic, asphaltic, or mixed base crude oils. Alternatively, if desired, various blended oils may be employed as well as residual oils, particularly those from which asphaltic constituents have been removed. The oils may be refined by any suitable method, for example, using acid, alkali, and/or clay or other agents such, for example, as aluminium chloride, or they may be extracted oils produced, for example, by solvent extraction with solvents, for example, phenol, sulphur dioxide, furfural, dkillloludi~lhyl ether, l~iL~ube~ "e, or ~,~ulunalclel ,yde.

The lubricating oil base stock conveniently has a viscosity of about 2.5 to about 12 cSt or mm2/sec and preferably about 3.5 to about 9 cSt or mm2/sec at 1 ûû~C

Additives used or treated as described herein may be employed in a lubricating oil cu~",uosilio~, which comprises lubricating oil, typically in a major p, upo, lion, and the additives, typically in a minor proportion. Additional additives may be i"cu"uGldL~d in the co",,uosiLion to enable it to meet particular requirements. Examples of additives which may be included in lubricating oil colll,uosiliu,,s are viscosity index improvers, corrosion inhibitors, oxidation inhibitors, friction modifiers, dia,uel~dllL~ lyu~ ,, metal rust inhibitors, anti-wear agents, pour point de,ul ~:SSdl IL::" and anti-foaming agents.

, Viscosity index improvers (or viscosity modihers) impart high and low temperature operability to a lubricating oil and permit it to remain shear stable at elevated temperatures and also exhibit acceptable viscosity or fluidity at low temperatures. Suitable compounds for use as viscosity modifiers are generally high molecular weight hy.ll UCdl boll polymers, including polyesters, and viscosity 21 965~7 W0 96/04355 P~~

index improver dispersants, which function as di~pe, ~al ,Ls as well as viscosity index improvers. Oil soluble viscosity modifying polymers generally have weight average molecular weights of from about 10,000 to 1,000,000, preferably 20,000 to 500,000, as duLul " ,i"ed by gel permeation ch, Ul lldLU~I d,Uhy or light scattering methods.

Corrosion inhibitors, also known as anti-corrosive agents, reduce the deyl dddliUn of the metallic parts contacted by the lubricating oil co",,uo:,ilion.

Oxidation inhibitors, or dl ILiUXk~dl ll~, reduce the tendency of mineral oils to deteriorate in service, evidence of such dt,Le, iu, dLion being, for example, the production of varnish-like deposits on the metal surfaces and of sludge, and viscosity growth. Suitable oxidation inhibitors include alkaline earth metal salts of alkyl-phenolthioesters having preferably C5 to C12 alkyl side chains, e.g., calcium nonylphenyl sulphide and barium octylphenyl sulphide dioctylphenylamine;
phenylalpha-naphthylamine; and phosphosulphurized or sulphurized h~ l U~ dl ~JI)I~S.

Other oxidation inhibitors or dl ILiUXiddl ll::- which may be used in lubricating oil co",~.osilio,ls comprise oil-soluble copper compounds.

Friction modifiers and fuel economy agents which are co",,udliule with the other iuy, ~.lie"L~ of the final oil may also be included. Examples of such materials are glyceryl ",u, ~ue~ , of higher fatty acids, for example, glyceryl mono-oleate, esters of long chain polycarboxylic acids with diols, for example, the butane diol ester of a dimerized unsaturated fatty acid, and oxazoline compounds.

Dispersants maintain oil-insoluble substances, resulting from oxidation during use, in suspension in the fluid, thus preventing sludge flnr.~ tinn and precipitation or deposition on metal parts. So-called ashless ui~,uel ~dl ll:~ are organic materials which form substantially no ash on combustion, in contrast to metal-containing (and thus ash-forming) d~L~I utll ll~. Suitable d; ,pe, :~dl ll~ include, for example, derivatives of long chain hy~l UCdl JUI I - 51 IhStitl ItPd carboxylic acids in which the hydl ucal ,on groups contain 50 to 400 carbon atoms, examples of such derivatives being derivatives of high molecular weight hydrocarbyl-5l Ihstih It~d succinic acid. Such hydl ucal boll-sl Ihstih It~d carboxylic acids may be reacted with, for example, a nitrogen-containing compound, advantageously a polyalkylene polyamine, or with an ester. Such nitrogen-uul Itdil lil l9 and ester ~WO96/0435~ -11- r~

dispersants are well known in the art, and require no further d~ :5ul i,uLioll here.
Particularly preferred, diau~l ac~ are the reaction products of polyalkylene amines with alkenyl succinic anhydrides.

As indicated above, a viscosity index improver ~ ,e, ~dl 11 functions both as a viscosity index improver and as a dial-e, ~a"l. Examples of viscosity index improver di~,ue, ~a"L~ suitable for use in lubricating cul "uo~ilions include reaction products of amines, for example polyamines, with a hydrocarbyl-sl Ihstitl It~od mono-or di-,dl Lu,cylic acid in which the hydrocarbyl substituent col ",ul ises a chain of sufficient length to impart viscosity index improving properties to the compounds.

Detergents and metal rust inhibitors include the metal salts, which may be overbased, of sulphonic acids, alkyl phenols, sulphurized alkyl phenols, alkyl salicylates, naul ,11 lelldle:~, and other oil-soluble mono- and di-,dl buxylit. acids.
Overbased metal sul,uhu, Id~ S wherein the metal is selected from alkaline earthmetals and magnesium, are particularly suitable for use as del~, ~e"l~.
Re,u, ~se"ldlive examples of d~Lt:, u,~, ,i ./rust inhibitors, and their methods of ,u, ~pa, dLion, are given in European Specif cation No. 208 560 A.

Antiwear agents, as their name implies, reduce wear of metal parts. Zinc dihydrocarbyl dilhic pl 105phdlt~5, for example those 1, le, ,liuned above, are very widely used as antiwear agents.

Pour point dep, ~:55dl 11~, otherwise known as lube oil flow improvers, lower the temperature at which the fiuid will flow or can be poured. Such additives are well known. Typical of those additives which improve the low temperature fluidity of the fluid are Cg to C18 dialkyl fumarate/vinyl acetate copolymers, polymethacrylates, and wax, Id~Jhll ,dlene. Foam control can be provided by an dl llirUdl I Idl 11 of the polysiloxane type, for example, silicone oil or polydimethyl siloxane.

~ Some of the above-l"~lllioned additives can provide a multiplicity of effects;
thus for example, a single additive may act as a ,i;:,pe, ~dl ll-oxidation inhibitor.
This approach is well known and need not be further elaborated herein.

When lubricating cv",posiliu"s contain one or more of the above-~ mel lliu"ed additives, each additive is typically blended into the base oil in an amount which enables the additive to provide its desired function. R~,ul t:se"ldlive WO 96/04355 -12 - ~ /O~n'j~ ~

effective amounts of such additives, when used in crankcase lubricants, are 8S
follows:

Additive mass, ~/O ai1~ mass C/o ai~
(Broad) (Preferred) Viscosity Modifier 0.01-6 0.01~
Corrosion Inhibitor 0.01-5 0.01-1.5 Oxidation Inhibitor 0.01-5 0.01-1.5 Friction Modifier 0.01-5 0.01-1.5 Dispersant 0.1-20 0.1-8 Dc~ /Rust Inhibitors+ 0.01-6 0.01-3 Anti-wearAgent 0.01-6 0.01~
Pour Point De~l~ssd"L 0.01-5 0.01-1.5 Anti-Foaming Agent 0.001-3 0.001-0.15 Mineral or Synthetic Oil Base Balance Balance Mass ~/0 active ingredient based on the final oil.
+ Relatively larger u, upodiol1s, for example, at least 10 mass ~/0 are normallyused for marine c~J,ul;~,dliuns.

When, a plurality of additives are employed it may ba desirable, although not essential, to prepare one or more additive ~,un~,el ,l, dles ~,o",~ i"~ the additives (a collce"~ sometimes being referred to herein as an additive package) whereby several additives can be added simultaneously to the base oil to form the lubricating oil ,_u",,uosiliu". Dissolution of the additive cuncelllltll~(s) into the lubricating oil may be facilitated by solvents and by mixing acco",,udnied with mild heating, but this is not essential. The concentrate(s) or additive package(s) will typically be formulated to contain the additive(s) in proper amounts to provide the desired concentration in the final formulation when the additive package is/are combined with a predt:L~""i"ed amount of base lubricant.Thus, one or more additives treated in acco, ddl lI e with the present invention can be added to small amounts of base oil or other uù,,,,udlil,le solvents along with other desirable additives to form additive packages containing active i"u, t:u'i~
in an amount, based on the additive package, of, for example, from about 2.5 to about 90 mass ~/0, and preferably from about 5 to about 75 mass ~/O and most preferably from about 8 to about 50 mass ~/0 by weight, additives in the d,Upl U,UI idl~ ,~JrUUUI lions with the remainder being base oil. Alternatively, as 21 q~597 ~wo s6/043ss -13 - r~ r1o~6 indicated above an olefinically unsaturated compound may be used to treat an additive package (uo"ce, 11l dle) conLdil ,i"g an active sulphur-co, ILdil lil l9 compound.

The hnal formulations may employ typically about 10 mass ~/0 of the additive package with the I ~ ai~ Idul being base oil.

The following Examples illustrate the invention.

The ability of an olefinically unsaturated compound to reduce the adverse effect of active sulphur-cul ILail ,i, Ig lubricating oil additives on nitrile seals was tested by i~ e~ y samples of a nitrile elastomer in a lubricating oil cu",uo~iLiu"
conLdi"i"g an active sulphur-conldi"i"g additive and the compound to be tested and COlllpdl i"g the elo, IydLiul, at break (EAB) and/or tensile strength (TS) of the ~ samples after i" " "e, sio" with the cc " ,:spondi"g figures before i" "ne, ~iul ,. The most effective compounds are those giving the smallest pe,uu"ldge loss in the elonydliull at break and/or tensile strength. Test Methods DIN 53521 and DIN 535û4 were used.

Example 1 A number of olefinically unsaturated compounds were tested in a lubricating oil ~o",uosiLiu" cullLdillillg 0.72 mass D/O nonyl phenol sulphide (NPS) and a dispersant a detergent and an dl ILiuxiddl ,L the elastomer being the acrylonitrile-butadiene rubber known as NBR 28. The pe,ue"lage loss in elonydliull at break (EAB) when using no olefinically unsaturated compound and 0.1 mass ~/0 and 0.25 mass ~/0 respectively of each of the compounds tested is given in Table 1 the p~ue"ldgt7s being based on the total mass of the lubricating .. . .

WO 96/04355 ~ 1 4 - PCI'II P95/03056 oil Culll,u05iLiul, with the compound. The pe, ~;~nLdge losses in TAB for the base formulation without the nonyl phenol sulphide and including the nonyl phenol sulphide were 31% and 54~/0 respectively.

Table 1 ~/0 Lo- s EAB
Additive 0.1% Additive 0.25% Additive ~Squalene 28 16 ~1 ,5,9-Cyclo-dodeudL, it:ne 40 37 a-Pinene 50 50 Limonene 45 38 1,3-Cyclo-hel~Lddit:"e 52 42 1,3,5-cyclo-he~ldll iene 48 43 Acenaphthylene 49 49 ,~-Pinene 42 28 ~Methylene cyulupe~ lldl ,e 45 34 ~Methylene c~;lolle,~d"e 32 32 *Camphene 50 SO
(Limonene 45 38) It can be seen from Table 1, in which additives for use in dCCOI ddl lI.,e with the invention are indicated by an asterisk, that 0.1~/0 squalene (a group (a) compound) gave a very significant reduction in loss of the elo,lgdLioll at break, compared with the figure (54%) for the base formulation containing the nonyl phenol sulphide, a further improvement being obtained by the use of 0.25% of this compound. Further, 1,5,9-cyclododecatriene, a group (b) compound, gave better results, at both 0.1% and 0.25% levels, than the other cyclic compounds cu, lldil ,i"g endocyclic double bonds, namely ~-pinene and limonene (which ~W096/04355 -15- r~,l/r.l 510'~ i6 contain only one endocyclic double bond), 1,3- and 1,1 ,5-cyulul le,OLdll iene (in which the two endocyclic double bonds are not separated at both ends by two saturated carbon atoms), and ace, Id~JhLl ,ylene (which contains aromatic, rather than aliphatic, double bonds). With regard to group (C) compounds, ,~-pinene, methylene cyl,loue, ,L~ne and methyiene cyclol It~Xdl ,e gave better results than limonene, in which the alicyclic ring is not saturated.

Example 2 The general procedure described in Example 1 was followed, except that the olefinically unsaturated compounds were added to an additive co"ce"L, dl~:
cur,Ldi"i"g 6.76 mass ~/0 nonyl phenol sulphide (NPS), based on the U-)llCellLldLI:~
without the oleri"i~,a"y unsaturated compound(s), and the test was carried out on a different batch of NBf~ 28 nitrile seals. The ~,unce"L, dL~: also included a Je, ::.dl IL, a detergent and an dl ILi~ iddl ll. The cu".e, ILI ~Le in each case was then diluted with oil to give a lubricating oil Cul, I,uosiLiGn co, ILdil lil Iy û.72 mass ~/0 NPS, based on the finished oil. The compounds were added to the conce, ILldLI~ in such ,ul uuu"iun5 as to give û. 1 mass ~/0 or 0.2 mass ~/0 of the compounds in the finished oil (including the compounds). Addition of the compounds to the conce"l, dles was effected at 60~C. The results obtained are given in Table 2.
The pel ~,e~ ILdgtl losses in EAB for the base formulation without the nonyl phenol sulphide and including the nonyl phenol sulphide were 31~/0 and 42% respectively.
The difference between the results obtained from the base formulations with the nonyl phenyl sulphide in Examples 1 and 2 was in part the result of using different batches of nitrile seals and in part a function of the test method used.

WO 96/04355 - 1 6 - r ~, I 111.1 ~s/q~nc~;

Table 2 ~/0 Los~ EAB
Additive 0.1 mass C/o Additive 0.2 mass ~/0 Additive ~Squalene 22 18 ~Geraniol 23 21 ~Farnesol 25 22 Decene 50 40 36 Decene mix 38 34 Nonene 37 36 ~1,5-Cyclo-octadiene 21 13 Limonene 40 35 Methyl-cyclopentadiene dimer 33 26 1,4-Cyclo-hexddi~"e 44 42 ~-Pinene 32 19 (Limonene 40 35~

It can be seen from Table 2, in which additives for use in acuu, ddl IU~ with the invention are indicated by an asterisk, that squalene, geraniol and farnesol, which are group (a) compûunds, gaYe sig~ iCdl l~iy better results than decene 50, decene mix and nonene, which are not sui~able for use in a~,cu~ -ldl l~,e with the invention. Further, 1,5-cyclooctadiene (a group (b) compound~, gave significant better results than limonene (which contains only one endocyclic double bond), methylcyclope"lddiel ,e (the compound tested was the dimer, which does not contain two endocyclic double bonds in the same ring), and 1,4-cyclùl1exddiel1e (in which the two endocyclic double bonds are not separated by two saturated carbon atoms). In addition, ~-pinene (a group (c) compound), gave Siyl ~irl~,dUily better results than limonene (in which the alicyclic ring is not saturated). All the compounds which are compounds to be used in acuul ddi IC'3 with the invention gave better results than methylcy-,lul.e"lcdiene dimer, the most effective of those ~1 96597 ~wo s6/043ss - 17 - r~l,~ . S/A~

compounds in Table 2 which are not suitable for use in acco, dd,)ce with the invention.

Example 3 The general procedure described in Example 1 was followed, except that the compounds to be tested, which were added to a lubricating oil cr."",osilion co~ ILnil lil 19 0.72 mass C/o nonyl phenol sulphide, based on the finished oil, were used in ulupollions of O.û5 mass ~~0, 0.1 mass ~/0 and 0.3 mass ~/0 respectively, based on the finished oil (with the olefinally unsaturated compound), and the elastomer was the acrylonitrile-butadiene rubber known as NBR 34. The finished oil also contained a dispersant, a detergent, and an dl lliu,~id~l ll. The results obtained are given in Table 3. The percentage loss in EAB for the base formulation including the nonyl phenol sulphide was 47~/0.

Table 3 ~/c Loss EAB
Additive 0.050/0 Additive 0.1% Additive 0.3~/c Additive ~Squalene 34 26 20 ~-Pinene 43 39 28 ~1,5,9-Cyclo-dodecdl,ialle 39 31 32 a-Pinene 50 50 47 Dipentene 49 48 43 C~1io~wllLddiene dimer 31 31 32 It will be seen from Figure 3, in which additives for use in acco~ ddnce with the invention are indicated by an asterisk, that at a treatment level of 0.3 mass ~/0, W096/04355 -18- r~ c -' squalene and ~-pinene (which are compounds for use according to the invention) gave si~"iri.,d, Illy better results than a-pinene and dipentene, and better results than c~clu,uel l~ddie~ dimer (which does not have two double bonds in the same alicyclic ring) and 1,5,9-cy._lodode~ dene.

Claims

Claims:

1. A lubricating composition obtainable by mixing:
(1) a major proportion of lubricating oil;
(2) an oil-soluble active sulphur-containing additive; and (3) an oil-soluble olefinically unsaturated compound selected from:
(a) acyclic compounds having at least two double bonds, adjacent double bonds being separated by two saturated carbon atoms;
(b) compounds containing an alicyclic ring, which ring contains at least eight carbon atoms and at least two double bonds, each double bond being separated from the closest adjacent double bond(s) by two saturated carbon atoms; and (c) compounds containing a saturated alicyclic ring and at least one exocylic double bond, provided that component (2) is not a dialkyldithiophosphoric acid salt when component (3) is selected from (a) or from (c).

2. A composition as claimed in claim 1, wherein the sulphur-containing additive is selected from sulphurized phenols, sulphurized olefins, dithiocarbamates and, when component (3) is selected from (b), from phosphorodithioates.

3. A composition as claimed in claim 1 or claim 2, wherein the olefinically unsaturated compound is as defined in (a) in claim 1 and is a linear terpene.

4. A composition as claimed in claim 3, wherein the terpene is squalene, geraniol, or farnesol.

5. A composition as claimed in claim 1 or claim 2, wherein the olefinically unsaturated compound is as defined in (b) in claim 1 and contains hydrogen and carbon atoms only.

6. A composition as claimed in claim 1 or claim 2, wherein the olefinically unsaturated compound is 1,5-cyclooctadiene.

7. A composition as claimed in claim 1 or claim 2, wherein the olefinically unsaturated compound is as defined in (b) in claim 1 and the said alicyclic ring contains at least three double bonds, each end of each double bond being separated from each adjacent double bond by two saturated carbon atoms.

8. A composition as claimed in claim 7, wherein the olefinically unsaturated compound is 1,5,9-cyclododecatriene.

9. A composition as claimed in claim 1 or claim 2, wherein the olefinically unsaturated compound is as defined in (c) in claim 1 and the exocyclic double bond, or one of the exocyclic double bonds, is between a carbon atom in the said alicyclic ring and an exocyclic carbon atom.

10. A composition as claimed in claim 1 or claim 2, wherein the olefinically unsaturated compound is as defined in (c) in claim 1 and the alicyclic ring contains at least six carbon atoms.

11. A composition as claimed in any one of claims 1, 2, 9 and 10, wherein the alicyclic ring is substituted by a bridging group that forms a four-membered ring with three of the ring carbon atoms.

12. A composition as claimed in any one of claims 1, 2, and 9 to 11, wherein apart from the bridging group (if any) and a side chain containing the exocyclic double bond, the carbon atoms in the said alicyclic ring are unsubstituted.

13. A composition as claimed in claim 1 or claim 2, wherein the olefinically unsaturated compound is .beta.-pinene.

14. A composition as claimed in any one of claims 1 to 13 wherein component (1) comprises a crankcase lubricating oil.

15. A composition as claimed in any one of claims 1 to 13, which also comprises one or more additives selected from ashless dispersants, viscosity index modifiers, detergents, antiwear agents and antioxidants.

16. A concentrate obtainable by dissolving in an oil of lubricating viscosity components (2) and (3) as defined in claim 1.

17. A treatment method which comprises treating an active sulphur-containing lubricating oil additive, concentrate, or composition with an olefinically unsaturated compound as specified in any one of claims 1 to 13.

18. The use of an olefinically unsaturated compound selected from:
(a) acyclic compounds having at least two double bonds, adjacent double bonds being separated by two saturated carbon atoms;
(b) compounds containing an alicyclic ring, which ring contains at least eight carbon atoms and at least two double bonds, each double bond being separated from the closest adjacent double bond(s) by two saturated carbon atoms; and (c) compounds containing a saturated alicyclic ring and at least one exocylic double bond;
to increase the nitrile elastomer compatibility of a lubricating composition containing an oil-soluble active sulphur-containing additive having a deleterious effect on the elastomer.