WO2011073960A1

WO2011073960A1 - Additive composition for engine oil

Info

Publication number: WO2011073960A1
Application number: PCT/IB2010/055964
Authority: WO
Inventors: Nguyen Truong-Dinh; Jean-Marc Savoie; Maruyama Masaki
Original assignee: Total Raffinage Marketing; Japan Energy Corporation
Priority date: 2009-12-18
Filing date: 2010-12-20
Publication date: 2011-06-23
Also published as: CN102812113A; BR112012014827A2; JP2013514425A; KR20120123304A; EP2513273A1; CA2784431A1; US20120329690A1; FR2954346B1; CN102812113B; RU2012127870A; JP5703309B2; MX2012007051A; FR2954346A1

Abstract

The invention relates to an additive composition including: (a) at least one compound including an azole heterocycle, (b) at least one alkylbenzene or alkylnaphthalene sulphonate not surbased with an alkali or alkaline-earth metal, (c) at least one carbodiimide, and (d) at least one antioxidant. The invention also relates to the use thereof as an additive composition for engine oil.

Description

ADDITIVE COMPOSITION FOR ENGINE OIL

Technical area :

The present invention relates to additive compositions for reducing the corrosivity of motor oils, in particular for diesel engines, with respect to metals and non-ferrous metals, principally copper, lead, tin and aluminum etc. and their alloys.

Technological background:

A motor lubricant has a very wide variety of additives, to enable it to reach the high performance levels required by users.

For example, due to environmental concerns, there is a growing demand for fuel savings in vehicles. The behavior of the engine lubricant in the reduction of friction will have a very important impact on the fuel consumption. It is mainly the quality of the lubricating bases, alone or in combination with viscosity index improving polymers and friction modifying additives, which gives the lubricant its friction reducing properties of the various components of the engine in operation and thus " fuel eco "or fuel savers. In particular, the formulation of efficient eco-fuel lubricant always leads to reinforcing the additivation of engine lubricants in terms of friction modifier. This chemical additive may however sometimes have adverse effects, such as increased lubricant corrosivity vis-à-vis some ferrous or non-ferrous metal parts of the engine. Thus, it has been found that the corrosivity with respect to copper, lead and tin of the motor oils is increased when they contain organometallic friction modifiers, such as, for example, organomolybdenum compounds or derivatives thereof. molybdenum, and / or non-"metal" or "ashless" organic friction modifiers, which are generally fatty substances and may be fatty esters, amines or fatty amides, fatty acids, fatty alcohols. .

This corrosivity, especially when hot, is measured, for example, according to the ASTM D6594 standard, by the "HTCBT" or "High Temperature Corrosion Bench Test" test.

The solutions commonly used to overcome these disadvantages are the reduction of the organic or organic metal friction modifier content of the lubricants, which greatly limits their "fuel eco" character. Metal-passivating compounds such as, for example, di or triazoles are also added, but without attaining acceptable levels of corrosion for non-ferrous metals.

U.S. Patent Application No. 5,614,483 discloses the use of carbodiimides, optionally in combination with calcium sulfonate, amine or phenolic antioxidants, passivants for non-ferrous metals, antiwear, extreme pressure additives, viscosity, antifoams, dispersants, detergents, to reduce aggression vis-à-vis the lead, zinc, or steel hydraulic oils containing esters as the base oil. This document does not disclose any specific combination of carbodiimide with the aforementioned additives, nor the possibility of using such combinations in motor oils containing organic and / or organometallic friction modifiers, to reduce their corrosivity to copper. , lead and tin.

Patent Application EP 0992571 describes the combination of a carbodiimide with a specific phenylnaphthylamine (excluding other diarylamines), and optionally with a copper passivator which may be a triazole or a thiadiazole, in a base oil which can be mineral or synthetic, for example of the ester type, said oil may contain additives such as: amine or phenolic antioxidants, VI improvers, sulfur, phosphorus or phosphorus sulfur anti-wear or extreme pressure, metal thiophosphates or thiocarbamates, antitussels, such as carboxylic acids, sulfonate detergents, phenates or metal carboxylates, for improving the oxidation stability of such oils. This document does not disclose any specific combination of carbodiimide, phenylnaphthylamine, triazole or thiadiazole with said additives, nor their use in motor oils containing organic and / or organometallic friction modifiers, to reduce their corrosivity to copper, lead and tin. Patent application WO 2008/095805 discloses additive compositions comprising borated triazoles and esters and optionally amine phosphates for reducing corrosivity to copper, lead and tin of lubricating compositions containing friction modifiers, which may be lycerol monoleate, or an organomolybdenum compound. The examples of this application do not specify which are the friction modifiers contained in the reference oils, whose corrosivity is reduced. However, according to the corrosivity values for Cu, Pb, Sn, measured according to ASTM D6594 on the reference oil, it seems that this friction modifier is not of primarily organic type, but well rather mostly of the type MoDTC. The lowering of the corrosivity level can be further improved, especially for copper.

Finally, these additive compositions involve a possible addition of phosphorus which can lead to the production of ash and catalyst poisons, detrimental to the aftertreatment systems installed on vehicles (especially diesel vehicles).

The patent application EP 2,080,798 discloses the addition of an additive composition comprising an acidic amide compound and a benzotriazole to a lubricant comprising molybdenum dithiocarbamate and organic friction modifiers, which may be fatty acid esters. or aliphatic amines. The addition of this additive composition decreases the corrosivity of said lubricant vis-à-vis copper and lead. However, this effect is achieved only with reduced levels of organic friction modifiers. Said additive compositions have an effect in lubricants strongly additive in molybdenum friction modifier, which increases the rate of metal in the lubricant and thus its tendency to produce ash, with the adverse effects on emissions mentioned above. Moreover, no effect is mentioned on the corrosiveness vis-à-vis tin. There is therefore a need for additives to further reduce the corrosivity to non-ferrous metals of engine lubricating compositions comprising organometallic and / or organic friction modifiers. In particular, there is a need for such additive compositions acting at high friction modifier levels, preferably at high levels of non-metallic friction modifiers, to make it possible to formulate "fuel eco" lubricants or fuel economizers, preferentially low ash. More particularly, there is a need for such additive compositions inducing the addition of a minimum of ash generating compounds.

Surprisingly, the Applicant has found that the introduction, in motor oils comprising friction modifiers, organic and / or organometallic, an additive composition comprising one or more carbodiimides, amine or phenolic antioxidants, azole compounds, and neutral sulfonate-type anticorrosive additives, allowed to inhibit the corrosiveness of said oils vis-à-vis non-ferrous metals.

The additive compositions according to the invention have a synergistic effect on reducing the corrosivity of these oils vis-à-vis non-ferrous metals.

They have the advantage of reducing the corrosivity to non-ferrous motor oil metals containing a high percentage of friction modifiers, in particular ash-free organic friction modifiers, corresponding to engine oil formulas. low ash and "fuel eco" effect.

Brief description of the invention

The present invention relates to additive compositions comprising:

(a) at least one compound comprising an azole heterocycle, chosen from di or triazole, the azole heterocycle optionally comprising a sulfur atom,

(b) at least one non-overbased alkylbenzene or alkylnaphthalene sulfonate of an alkali or alkaline earth metal, the alkyl substituent (s) of which contain from 7 to 12 carbon atoms, preferably from 8 to 10 carbon atoms,

(c) at least one carbodiimide of the formula X-N = C = N-Y, wherein X and Y are, independently of one another, hydrocarbon radicals comprising from 8 to 60 carbon atoms, of formula (I):

(I) where R 1 is an aliphatic or aromatic mono group, substituted or unsubstituted, comprising from 2 to 20 carbon atoms,

R2 is either hydrogen, an aliphatic group, or an aromatic mono, substituted or unsubstituted, comprising from 2 to 20 carbon atoms,

R3 is either hydrogen or an aliphatic or monoaromatic group, substituted or unsubstituted, condensed or not, comprising from 2 to 20 carbon atoms.

(d) at least one antioxidant chosen from secondary amines whose nitrogen atom is connected to at least one aryl group, or from phenols substituted on at least one of their ortho position, preferably both, by alkyl groups comprising 1 to 10 carbon atoms, preferably 1 to 3 carbon atoms, and their dimers.

Preferably, the additive compositions according to the invention comprise, as compound (c), at least one carbodiimide wherein X and Y each carry 2 or 3 substituents, in ortho, or ortho and para, with respect to the carbodiimide group, and wherein at least one of these substituents is a branched aliphatic chain having at least 3 carbon atoms or a cycloaliphatic substituent having 5 to 6 carbon atoms.

Preferably, the additive compositions according to the invention comprise, as compound (a), at least one benzotriazole of formula (V):

where R6 and R7 are, independently of one another, hydrocarbon groups having from 1 to 30 carbon atoms, preferably from 2 to 20 carbon atoms, linear, branched or cyclic, and which may contain an atom of oxygen, sulfur or nitrogen.

Preferably, the additive compositions according to the invention comprise, as compound (b), at least one neutral dialkylbenzene or dialkyinaphthalene sulfonate of an alkali or alkaline earth metal, the alkyl substituents of which contain from 7 to 12 carbon atoms.

According to a preferred embodiment, in the additive compositions according to the invention, the compound (b) has a BN, measured according to the ASTM D2892 standard, less than 20, preferably less than 15 mg of KOH / gram. According to one embodiment, in the additive compositions according to the invention, the secondary amines optionally present as compound (d) are chosen from secondary amines of formula of formula R8-NH-R9, where R8 and R9 are independently one of the other :

A phenyl group, optionally substituted, preferably para to the amine function, with alkyl or alkenyl groups containing from 1 to 10 carbon atoms, preferably from 1 to 3 carbon atoms,

A naphthyl group, optionally substituted, with alkyl or alkenyl groups comprising from 1 to 10 carbon atoms, preferably from 1 to 3 carbon atoms, or else R8 is a phenyl group, and R9 forms with the nitrogen atom; of the amino function and the R8 ring a C6 heterocycle, optionally substituted with alkyl groups.

Preferably, the secondary amines optionally present as compound (d) in the additive compositions according to the invention are chosen from diphenylamines, preferably having their phenyl groups substituted in the ortho group by alkyl or alkenyl groups containing from 1 to 10, preferentially from 1 to 3 carbon atoms, unsubstituted phenylnaphthylamine, phenylnaphthylamines substituted by at most 2 alkyl or alkenyl groups having from 1 to 10, preferably from 1 to 3 carbon atoms.

According to a preferred embodiment, the additive compositions according to the invention comprise at least one secondary amine as compound (d).

Particularly preferably, in the additive compositions according to the invention, the percentages by weight [a], [b], [c] and [d] of the compounds (a), (b), (c) and (d) are present in synergistically effective ratios, and / or verify:

· [C]: [a] from 10 to 100, preferably from 20 to 50,

[C]: [b] is between 1 and 10, preferably between 2 and 5,

• [c]: [d] is between 1 and 10, preferably between 2 and 5.

The present invention also relates to lubricating compositions containing such additive compositions.

Thus, the subject of the present invention is lubricant compositions for an engine, preferably for a diesel engine, comprising an additive composition as described above, one or more base oils, and at least one friction modifier, which may be:

(i) at least one organometallic friction modifier, preferably chosen from organomolybdenum or organotungstate compounds, preferentially molybdenum dithiocarbamates,

and or

(ii) at least one organic friction modifier selected from fatty amines, fatty alcohols, fatty acids, fatty acid esters, preferentially glycerol esters such as mono-, di- or tri heptanoate, oleate, stearate, isostearate, linoleate, glycerol caprylate, citrates, tartrates, malates, lactates, mandelates, glycolates, hydroxypropionates, hydroxyglutarates, and their derivatives.

Preferably, the lubricant compositions according to the invention comprise between 0.8% and 5% by weight, preferably between 1 and 1.5% by weight of friction modifiers.

According to a preferred embodiment, the lubricant compositions according to the invention comprise at least 0.8% and 5% by weight, preferably between 1 and 1.5% by weight of organic friction modifiers.

Preferably, the lubricant compositions according to the invention comprise between 0 and 0.5% by weight, preferably between 0.01% and 0.3% by weight of organometallic friction modifier. According to a particularly preferred embodiment, in the lubricant compositions according to the invention, the amount of additive composition as described above is such that the compound (c) represents from 0.5 to 4%, preferentially from 0.8 to 3 , 5% by weight, preferably from 1 to 3% by weight of said lubricating compositions. The present invention also relates to the use of an additive composition as described above to reduce the corrosiveness vis-à-vis copper, lead and tin, measured according to ASTM D6594, a hu an engine, preferably for a diesel engine, comprising at least one friction modifier which may be:

and or

(ii) at least one organic friction modifier selected from fatty amines, fatty alcohols, fatty acids, fatty acid esters, preferentially glycerol esters such as mono-, di- or triheptanoate, oleate, stearate, isostearate, linoleate, glycerol caprylate, citrates, tartrates, malates, lactates, mandelates, glycolates, hydroxypropionates, hydroxyglutarates, and their derivatives.

The present invention is, finally, relating to a use as described above, wherein the engine oil is a motor oil, preferably for diesel engine, comprising the friction modifier or modifiers described above. Detailed description of the invention

Carbodiimides (c)

The additive compositions according to the invention comprise one or more carbodiimides of formula: XN = C = NY, where X and Y are, independently of one another, hydrocarbon radicals comprising from 8 to 60 carbon atoms, of formula (I):

where R 1 is an aliphatic or aromatic mono group, substituted or unsubstituted, comprising from 2 to 20 carbon atoms,

In a particularly preferred manner, X and Y are substituted at the two ortho positions from the carbodiimide group, and optionally at the para position of said group.

The substituents can be C 2 -C 20 alkyl or cycloalkyl groups, such as the ethyl, propyl, isopropyl, butyl, tert-butyl, cyclohexyl or dodecyl groups, or aryl or aralkyl groups with 6 to 15 carbon atoms, such as phenyl or tolyl, benzyl, naphthyl ...

Preferentially, these substituents are aliphatic substituents comprising at least 3 carbon atoms, branched or cyclic.

In particular, preference will be given to carbodimides where X and Y each carry 2 or 3 substituents ortho or ortho and para with respect to the carbodiimide group, and wherein at least one of these substituents is a branched aliphatic chain having at least 3 carbon atoms. or a cycloaliphatic substituent having 5 to 6 carbon atoms.

Particularly preferred compounds include N, N'-di (2,6-diisopropylphenyl) carbodiimide or N, N'-di (2,4,6-triisopropylphenyl) carbodiimide.

The carbodiimides used may also be dimers, oligomers or polymers of carbodiimides, of formula: X - (- N = C = NY) _p = N = C = NY,

Where X and Y are as defined above, with the substituents defined above, and p is an integer between 0 and 100, preferably between 0 and 50, preferentially between 0 and 40.

Carbodiimides, their dimers, oligomers and polymers may be used alone or in admixture.

Azole compounds (a):

The additive compositions according to the invention comprise one or more compounds comprising an azole heterocycle, optionally comprising a sulfur atom (thiaazoles).

These are preferentially diazoles or triazoles (124 or 123 triazoles), or thiaazoles such as benzothiaazoles, mercaptobenzothiazoles, thiadiazoles, dimercaptothiadiazoles, etc.

The triazoles 1, 2,4 may be, for example, the metal passivatives described in US Pat. No. 4,734,209, column 1, and column 2, lines 1 to 35, of formula (II):

Wherein R4 and R5 are, independently of one another, C1-C20 alkyl, C3-C20 alkenyl, C5-C12 cycloalkyl, C7-C13 aralkyl, C6-C10 aryl, or both form with the nitrogen atom to which they are attached a C5, C6 or C7 heterocycle, or R4 and R5 are groups of formula (II): R3X [(alkylene) O] n (alkylene) -

with:

X = O, S, or N

Alkylene = C1-C12 alkylene radical

n is either 0 or an integer between 1 and 6, or R4 is as described above and R5 is a radical of formula (III)

(III)

or R5 is a radical of formula (III) and R4 a radical of formula (IV):

[alkylene] n-N (R4) -A- [N (R4) 2] m, (IV)

with m = 0 or 1 and if m = 0, A is a radical of formula (III) and, when m = 1, A is alkylene or C6-C10 arylene. Preferred triazoles are, for example, benzotriazole, of formula (V):

Amino or phenolic antioxidants (d):

Components (d) are phenols, or secondary amines, whose amino and phenol function is sterically hindered, well known to those skilled in the art for their antioxidant action in lubricants.

The phenolic antioxidants of the compositions according to the invention are phenols substituted on at least one of their ortho positions, preferably both, with alkyl groups comprising from 1 to 10 carbon atoms, for example methyl, isopropyl or tert-butyl groups, preferentially from 1 to 3 carbon atoms. They can also be used in the form of dimers.

The aminated antioxidants of the compositions according to the invention are secondary amines in which the nitrogen atom is connected to at least one aryl group.

Preferably, they are secondary amines of formula R8-NH-R9, where R8 and R9 are, independently of one another:

A naphthyl group, optionally substituted, with alkyl or alkenyl groups containing from 1 to 10 carbon atoms, preferably from 1 to 3 carbon atoms. or R8 is a phenyl group, and R9 forms with the nitrogen atom of the amino function and the R8 ring a C6 heterocycle, optionally substituted with alkyl groups. Sulfonates of alkali and alkaline earth metals (b)

The metal sulfonates used in the additive compositions according to the present invention are well known to those skilled in the art for their inhibitory action of corrosion of ferrous metals in lubricants.

These are alkyl benzene or alkyl naphthalene sulfonates of alkali and alkaline earth metals, whose alkyl chain or chains contain from 7 to 12 carbon atoms, preferably from 8 to 10 carbon atoms. The preferred sulfonates are dialkyl benzene or dialkyl naphthalenes whose alkyl chains contain from 7 to 12 carbon atoms, preferably from 8 to 10 carbon atoms. The preferred alkali and alkaline earth metals are calcium, barium, magnesium, zinc, preferentially calcium.

These sulfonates act on the surface of metal parts by creating a protective film by reaction with metal surfaces. They are distinguished from sulphonates used as detergents in oils, for example engine oils, or marine engine oils, which act within the oil, thanks to their micellar structure and their reserve of basicity provided by overbasing, for example metal carbonates. The basicity provided is characterized by BN or "Base Number", measured according to ASTM D2896, in mg KOH / gram of detergent. The detergents typically have a BK greater than 80 mg KOH / gram of detergent or greater than 150, up to and including up to 4000 mg KOH / gram of detergent. The sulfonates themselves have very little intrinsic basicity and must be overbased when used as detergents.

When used as anticorrosive, on the contrary, the sulfonates must not be overbased (they must be "neutral"), to be able to act on the surface and to bind to the metal surfaces of the parts to be protected.

When used as anticorrosion, the sulphonates have a basicity according to ASTM D2896 almost nil, less than 30, preferably less than 20, or even less than 15 mg of KOH / g of sulphonates.

The sulphonates used as detergents typically have alkyl chains containing from 18 to 24 carbon atoms, longer than those of the sulphonates of the compositions according to the invention according to the invention. These long chains make it possible to keep the micelles of overbased detergents in suspension in the oil, which distinguishes them from the anticorrosion sulfonates according to the invention. Preferably, the compounds (a), (b), (c) and (d) are present in synergistically effective amounts in the additive compositions according to the invention.

Preferably, in the additive compositions according to the invention, the ratios between the mass percentages of the compounds (a), (b), (c) and (d) respectively denoted [a], [b], [c] and [ d] satisfy the following three conditions:

[c]: [a] is between 10 and 100, preferably between 20 and 50,

[c]: [b] is between 1 and 10, preferably between 2 and 5,

[c]: [d] is between 1 and 10, preferably between 2 and 5.

An advantage of the additive compositions according to the invention is to reduce the corrosivity with respect to copper, lead or tin of lubricating compositions containing a high percentage of organic and / or organometallic friction modifiers, for example between 0.8 and 5% by weight, or between 0.9 and 2% by weight, or between 1 and 1.5% by weight. When the lubricating compositions contain only molybdenum organic friction modifiers, this can still represent between 400 and 2500 ppm of molybdenum, or between 450 and 1000 ppm, or between 500 and 1500 ppm of molybdenum.

Thus, the additive composition reduces the corrosivity, vis-à-vis non-ferrous metals mentioned above, of lubricating compositions themselves having a "fuel eco" effect or fuel economy.

Another advantage of the additive compositions according to the invention is to reduce the corrosivity with respect to copper, lead or tin of lubricating compositions containing a high percentage of organic friction modifiers, for example comprising between 0.degree. , 5% and 5% by weight, preferably between 0.8 and 5% by weight, or between 0.7% and 4% by weight, or between 0.9 and 2% by weight, or between 1% and 1%. , 5% by weight of organic friction modifiers.

Thus, the additive compositions according to the invention reduce the corrosivity, vis-à-vis the non-ferrous metals mentioned above, of lubricating compositions whose effect "fuel eco" or fuel economy, is obtained essentially or exclusively with organic MF, and therefore with a zero or reduced rate (for example between 0 and 0.5% by weight or between 0.01% and 0.3% by weight) of organometallic friction modifiers generating ash.

Lubricating compositions:

The lubricant compositions according to the invention are motor oils, preferably for diesel engines, comprising an additive composition comprising the components (a), (b), (c), and (d) described above, organic friction modifiers and and / or organometallic and all types of lubricating bases, polymer, viscosity index improver, and other additives adapted to their use. Preferably, the amount of additive composition is such that the compound (c) represents from 0.5 to 4%, preferably from 0.8 to 3.5% by weight, or from 1 to 3% by weight of said lubricating compositions.

• Friction Modifiers (MF):

The lubricating compositions according to the invention contain organometallic or organic friction modi fi cators known to those skilled in the art and commonly used in the formulation of motor oils.

The metal compounds are, for example, complexes of transition metals such as Mo, W, Fe, Cu, Zn, or metals such as Sb, Sn, the ligands of which may be hydrocarbon compounds containing oxygen atoms, nitrogen , sulfur or phosphorus. In particular, organic compounds containing tungsten or molybdenum may be particularly effective, such as for example molybdenum dithiocarbamates or MoDTC and will be preferred in the lubricant compositions according to the invention.

The organic friction modifiers are, for example, fatty alcohols, fatty acids, fatty amines, fatty esters. These compounds can optionally be mono or polyethoxylated. Polyethoxyethers of unsaturated fatty acids are thus used as organic friction modifiers. Borated derivatives of fatty esters can also be used as friction modifiers.

The fatty esters may be esters of polyols and of fatty acids, for example mono-, di- or triheptanoate, oleate, stearate, isostearate, linoleate, glycerol caprylate, preferentially glycerol monooleate and monoisostearate.

Certain C2-C8 monoalcohol esters and polyacids, such as citrates, tartrates, malates, lactates, mandelates, glycolates, hydroxypropionates, hydroxyglutarates or their borated derivatives, are also used as organic friction modifiers. These organic friction modifiers may also be fatty amides, such as oleyamides, for example used in combination with glycerol oleates.

Fatty amines used as organic friction modifiers are often derived from natural vegetable oils, for example coconut oil, palm oil, olive oil, peanut oil, rapeseed oil, sunflower oil, soybean oil, cotton oil, flax, beef tallow, ...

The preferred organic friction modifiers in the lubricant compositions according to the invention are glycerol esters, fatty amines, citrates, as described above. These friction modifiers can be used alone or in a mixture. The lubricating compositions according to the invention may contain exclusively one or more organic MF, which contributes to their "ashless" or ashless character, or exclusively one or more organometallic MFs, or a mixture of one or more organic MFs with one or more organic MFs. or more organometallic MFs.

Friction modifying additives are generally present at levels of between 0.01 and 5%, preferably 0.01 and 1.5%, in engine lubricants. · Lubricating bases:

The lubricant compositions according to the present invention comprise one or more base oils. These bases generally represent at least 50% by weight of the lubricating compositions, generally greater than 70% and up to 85% or more.

The base oil (s) used in the compositions according to the present invention may be oils of mineral or synthetic origin of groups I to VI according to the classes defined in the API (American Petroleum Institute) classification, alone or as a mixture.

The mineral base oils according to the invention include all types of bases obtained by atmospheric and vacuum distillation of crude oil, followed by refining operations. The base oils of the compositions according to the present invention may also be synthetic oils, such as certain esters of carboxylic acids and alcohols, or polyalphaolefins.

These oils can also be oils of natural, vegetable or animal origin.

These different categories of oil can be used alone or as a mixture.

• Polymers improving viscosity:

The viscosity index improving polymers make it possible to guarantee a good cold behavior and a minimum viscosity at high temperature, in particular to formulate multi-grade oils. The introduction of these compounds into the lubricating compositions allows them to achieve viscosity index (VI) values giving them good fuel eco properties or fuel economy. Examples of these compounds include polymeric esters, olefins copolymers (OCP), homopolymers or copolymers of styrene, butadiene or isoprene, polymethacrylates (PMA). They are conventionally present at levels of the order of 0 to 40%, preferably 5 to 15% by weight, in the lubricant compositions for a four-stroke engine.

• Other additives:

The additives can be added individually, or in the form of additives, guaranteeing a certain level of performance to the lubricating compositions, as required, for example for a diesel lubricant ACEA (European car manufacturers) or JASO (Japan Automobile Organization Standards). These are for example and not limited to: Dispersants, generally representing between 5 and 8% by weight of the lubricating compositions. Dispersants such as succinimides, PIB (polyisobutene) succinimides, Mannich bases ensure the maintenance in suspension and evacuation of insoluble solid contaminants formed by the secondary oxidation products that are formed when the engine oil is in use.

Antioxidants generally represent between 0.5 and 2% by weight of the lubricating compositions. Antioxidants delay the degradation of oils in service, which can result in the formation of deposits, the presence of sludge, or an increase in the viscosity of the oil. They act as free radical inhibitors or destroyers of hydroperoxides. Among the commonly used antioxidants are phenolic antioxidants, sterically hindered amines.

Another class of antioxidants is that of oil-soluble copper compounds, for example copper thio or dithiophosphate, copper and carboxylic acid salts, copper dithiocarbamates, sulphonates, phenates, acetylacetonates. Copper salts I and II, succinic acid or anhydride are used.

Antiwear additives, generally representing between 1 and 2% by weight of the lubricating compositions. The anti-wear additives protect the friction surfaces by forming a protective film adsorbed on these surfaces. The most commonly used is Zinc di thiophosphate or DTPZn. This category also contains various phosphorus, sulfur, nitrogen, chlorine and boron compounds.

Detergents generally represent between 2 and 4% by weight of the lubricating compositions The detergents are typically alkali metal or alkaline earth metal salts of carboxylic acids, sulfonates, salicylates, naphthenates, as well as the salts of phenates.

They typically have a BN according to ASTM D2896 greater than 40, or 80 mg KOH / gram of detergent, and are most often overbased, with BN values typically of the order of 150 and more, or even 250 or 400 or more. (expressed as mg KOH per gram of detergent).

And also antifoam, pour point depressants, ...

Example 1

A reference engine oil (grade 0W30) according to the SAE J300 classification (Society of American Engineers) has been prepared. It contains a blend of API Group III mineral base oils and ATIEL (American Petroleum Institute, Technical Association of the European Lubricants Industry), a diesel engine oil additive package including dispersants , anti-wear, detergents, antioxidants, antifoam, providing the performance levels required by the ACEA (Association of European Automakers) or the JASO (Japan Automobile Standards Organization), and a polymer improving VI, copolymer d alkyl methacrylates.

The elemental analysis of the reference oil is given in the following table, for illustrative purposes in ppm, as well as other characteristics:

This reference motor oil A was additivated with an organometallic friction modifier (molybdenum dithiocarbamate), with an organic friction modifier (fatty amine), and with a mixture of these two friction modifiers, to formulate the oils respectively. A, B, and C.

These oils A, B and C have in turn been added with amine antioxidants, metal soaps, carbodiimides, benzotriazole, alone or as a mixture, to formulate oils D to M.

The oils F, L and M comprise an additive composition according to the invention.

The corrosivity of these different oils vis-à-vis non-ferrous metals was measured according to the HTCBT test performed according to ASTM D6594. 4 coupons of Cu, Pb, Sn and Bronze Phosphorus are immersed in the oil at 135 ° C with a stream of air for a well defined time. The contents of copper, lead and tin elements dissolved in the oil after the test are measured, in ppm, as the appearance of the coupon Cu is evaluated by its color according to a color scale. The higher the content of these elements, the more the oil is corrosive with respect to the corresponding metals and a rating of 1 (low corrosivity) to 4 (high corrosivity) is also performed on the Cu coupon.

Table 1 groups together the compositions and properties of these different oils.

The oil A containing an organometallic friction modifier (MoDTC), without additivation according to the invention, becomes very corrosive with respect to the copper relative to the reference containing no friction modifier (oil ref). The addition of some of the components of the additive composition according to the invention makes it possible to reduce the corrosivity with respect to copper, but has an adverse effect on the corrosiveness with respect to the lead (oils D and E, compare to oil A).

On the other hand, the addition of an additive composition according to the invention (comprising a diphenylamine, a calcium sulphonate, a carbodiimide and a triazole) makes it possible to reduce the corrosivity with respect to copper and lead, while now the absence of corrosiveness vis-à-vis the tin (oil F).

The oil B, containing an organic friction modifier (fatty amine), without additivation according to the invention, becomes very corrosive with respect to copper and lead compared to the reference containing no MF (oil ref). .

The addition in this oil B of diphenylamine further accentuates the corrosivity with respect to copper and lead (oilG).

The addition of calcium sulphonate, or triazole in oil B, makes it possible to reduce the corrosivity with respect to copper but greatly increases the corrosivity with respect to lead (oils H and J).

The addition of carbodiimide to oil B makes it possible to reduce the corrosion with respect to copper, but the corrosivity with respect to lead remains high, although it is lower than reference B (oil I compared to oil B). The addition of carbodiimide in combination with triazole, improves the result (oil K), but the corrosivity vis-à-vis the lead remains significant.

The addition of an additive composition according to the invention (comprising a diphenylamine, a calcium sulphonate, a carbodiimide and a triazole) makes it possible to obtain excellent results, and reduces the corrosivity of the oil containing an MF organic at the level of the reference oil without MF (Oil L, to compare with oil ref).

The oil C, containing an organic friction modifier (fatty amine) and an organometallic friction modifier (MoDTC), without additivation according to the invention, becomes very corrosive towards the copper, and sees its corrosivity vis-à-vis the - Lead also increase, compared to the reference containing no MF (oil ref).

The addition of an additive composition according to the invention (comprising a diphenylamine, a calcium sulphonate, a carbodiimide and a triazole) makes it possible to obtain excellent results, and reduces the corrosivity of the oil containing an MF organometallic and an organic MF at or below that of the reference oil without MF (Oil M, to compare with oil ref).

It should be noted that oils F, L and M show no corrosivity with respect to tin (and others) and pass the requirements of the test, as well as oil D and E.

Example 2

Another engine oil, also grade 0W30 according to the SAE J300 classification (Society of American Engineers), has been prepared. It contains a mixture of Group III and IV Mineral Base Oils according to the classification of ΓΑΡΙ and ATIEL (American Petroleum Institute, Technical Association of the European Lubricants Industry), a diesel engine oil additive package including dispersants, anti-wear, detergents, antioxidants, antifoam, providing the performance levels required by the ACEA (European Manufacturers Association). Automobiles) or the JASO (Japan Automobile Standards Organization), and a polymer improving VI, LZ7418A alkyl methacrylate copolymer.

This oil has been additivated with an organic friction modifier (fatty amine), amine antioxidants, metal soaps, carbodiimides, benzotriazole, alone or as a mixture, to formulate oils N to R. The oil R comprises an additive composition according to US Pat. 'invention.

The corrosivity of these different oils vis-à-vis non-ferrous metals was measured according to the HTCBT test performed according to ASTM D6594. Table 2 groups together the compositions and properties of these different oils. N to R oils have corrosivity to equivalent copper and tin. On the other hand, the corrosivity with respect to the lead of the oil R comprising a composition according to the invention is substantially lower than that of the oils N, O, P, and Q.

Table 1:

Table 2

Claims

1. Additive composition comprising

(c) at least one carbodiimide of the formula X-N = C = N-Y, where X and Y are, independently of one another, hydrocarbon radicals comprising from 8 to 60 carbon atoms, of formula (I):

R3 is either hydrogen or an aliphatic or monoaromatic group, substituted or unsubstituted, condensed or not, comprising from 2 to 20 carbon atoms. (d) at least one antioxidant chosen from secondary amines whose nitrogen atom is connected to at least one aryl group, or from phenols substituted on at least one of their ortho position, preferably both, by alkyl groups comprising 1 to 10 carbon atoms, preferably 1 to 3 carbon atoms, and their dimers.

2. Additive composition according to claim 1 comprising, as compound (c), at least one carbodiimide wherein X and Y each carry 2 or 3 substituents, ortho, or ortho and para relative to the carbodiimide group, and where at least one of these substituents is a branched aliphatic chain having at least 3 carbon atoms or a cycloaliphatic substituent having 5 to 6 carbon atoms.

3. Additive composition according to one of claims 1 to 2 comprising, as compound e of formula (V):

(V)

4. Additive composition according to one of claims 1 or 3 comprising, as compound (b),

at least one neutral dialkylbenzene or dialkylnaphthalenesulfonate of an alkali or alkaline earth metal, the alkyl substituents of which contain from 7 to 12 carbon atoms.

5. Additive composition according to one of claims 1 to 4 wherein the compound (b) at a BN, measured according to ASTM D2892, less than 20, preferably less than 15 mg of KOH / gram.

6. Additive composition according to one of claims 1 to 5 wherein the secondary amines optionally present as compound (d) are chosen from secondary amines of formula of formula R8-NH-R9, where R8 and R9 are independently one of the other:

A naphthyl group, optionally substituted, with alkyl or alkenyl groups containing from 1 to 10 carbon atoms, preferably from 1 to 3 carbon atoms,

or R8 is a phenyl group, and R9 forms with the nitrogen atom of the amino function and the R8 ring a C6 heterocycle, optionally substituted with alkyl groups.

7. The additive composition according to claim 6, wherein the secondary amines optionally present as compound (d) are chosen from diphenylamines, preferably having their phenyl groups substituted in the ortho group by alkyl or alkenyl groups containing from 1 to 10, preferably 1 to 3 carbon atoms, unsubstituted phenylnaphthylamine, phenylnaphthyl amines substituted by at most 2 alkyl or alkenyl groups having from 1 to 10, preferably from 1 to 3 carbon atoms.

8. Additive composition according to one of claims 1 to 7 comprising at least one secondary amine as compound (d).

9. Additive composition according to one of claims 1 to 8 wherein the percentages by mass [a], [b], [c] and [d] of the compounds (a), (b), (c) and (d) are present in synergistically effective ratios, and / or verify:

• [c]: [a] between 10 and 100, preferably between 20 and 50,

[C]: [b] is between 1 and 10, preferably between 2 and 5,

• [c]: [d] is between 1 and 10, preferably between 2 and 5.

10. A lubricating composition for an engine, preferably for a diesel engine, comprising an additive composition according to one of claims 1 to 9, one or more base oils, and at least one friction modifier, which may be:

and or

(ii) at least one organic friction modifier chosen from fatty amines, fatty alcohols, fatty acids, fatty acid esters, preferentially glycerol esters such as mono-, di- or triheptanoate, oleate, stearate, isostearate, linoleate, glycerol caprylate, citrates, tartrates, malates, lactates, mandelates, glycolates, hydroxypropionates, hydroxyglutarates, and their derivatives.

1. A lubricating composition according to claim 10 comprising between 0.8% and 5% by weight, preferably between 1 and 1.5% by weight of friction modifiers.

12. Lubricating composition according to claim 10 or 1 1 comprising at least 0.8% and 5% by weight, preferably between 1 and 1.5% by weight of organic friction modifiers.

13. Lubricating composition according to claims 10 to 12 comprising between 0 and 0.5% by weight, preferably between 0.01% and 0.3% by weight of organometallic friction modifier.

14. Lubricating composition according to claims 10 to 13, wherein the amount of additive composition is such that the compound (c) represents from 0.5 to 4%, preferably from 0.8 to 3.5% by weight, preferably from 1 to at 3% by weight of said lubricating composition.

15. Use of an additive composition according to one of claims 1 to 9 to reduce the corrosiveness vis-à-vis copper, lead and tin, measured according to ASTM D6594, a engine oil, preferably for a diesel engine, comprising at least one friction modifier which may be:

and or

16. Use according to claim 15 wherein the engine oil is according to one of claims 10 to 15.