DE60107218T2 - LUBRICANT COMPOSITIONS CONTAINED A DISPERSANT, A MOLYBDENUM TRINUCLEAR COMPOUND, AND A VARIOUS OXYGEN AGENT - Google Patents

Description

These The invention relates to a method for controlling the soot-induced viscosity of diesel engine lubricant compositions.

Internal combustion engines usually operate by burning fuels, which in turn generate the power needed to propel vehicles. In the case of a diesel engine, the fuel is a diesel fuel and its combustion generally results in emissions from the exhausts of these vehicles, which include three major components. These are soot, solids and nitrogen oxides (the latter is abbreviated to NO _x here for convenience). Of these, soot is generally formed as a result of incomplete combustion of the fuel. Carbon black adversely affects the performance of lubricants by increasing their viscosity (by accumulating soot in the lubricant) and causing wear. It is also important that the presence of soot does not increase the viscosity of the lubricant to undesirably high levels, and it is also important to maintain the viscosity within the normal ranges for rapid and clean discharge of the oil from the engine during maintenance is. The formation of soot can be reduced to some extent by operating the diesel engine at relatively higher temperatures. However, these higher temperatures, while mitigating soot formation, also result in the formation of increased levels of NO _x . However, if the engine temperature is lowered, incomplete combustion results, and although this reduces the amount of NO _x formed in the emissions, it also substantially increases the amount of soot produced. The soot formed in this way can manifest itself in two ways. It can either show up as thick black smoke leaking from the vehicle's exhaust, or it can accumulate in the lubricant of the engine. As the soot builds up in the lubricant, the latter becomes more and more viscous and, upon reaching a critical level, can lead to gellation of the lubricant and eventually cause seizure of the engine. Several methods have been tried to alleviate this problem, including the use of one or more of dispersants, metal salts, and solvents, which may be ethers, esters, and the like. The dispersants act by forming a coating of the dispersant on the surface of the carbon black particles, thereby minimizing the tendency of the carbon black particles to agglomerate. However, the power of the dispersants to perform this function decreases over time, and thus one of the methods for improving the service life of lubricants, especially crankcase lubricants, is to improve the ability to maintain the dispersing action of crankcase lubricants. This can be z. B. can be achieved by minimizing the risk of oxidation of the dispersant under the conditions prevailing during use in the engines.

Recently published US-A-5 837 657 describes a method for improving the performance of a sooted diesel oil and for controlling soot-induced viscosity increase by adding a small amount of a trinuclear molybdenum compound having the structure Mo ₃ S _k L _n Q _z to the diesel oil , The ability of this compound to bind to carbon black is controlled with conventional antioxidants such as. As diphenylamine, hindered phenols and zinc dithiodiphosphates (ZDDP) compared. The conclusion is that trinuclear molybdenum compounds are far superior to other compounds tested in controlling carbon black-induced viscosity increase.

The The aim of the present invention is the development of a process to alleviate the problem of soot-induced viscosity increase in diesel lubricants by maximizing the period in which the Soot in the lubricant remains in a well-dispersed state, whereby the increase in the absolute viscosity of the lubricant for so long as possible within the desired Areas remains, d. h, that the degree of soot-induced viscosity increase the lubricant longer Time is minimized than was previously possible. At the same time the object of the present invention in improving the ability the maintenance of the dispersing action of these lubricants.

It However, it has now been found that the performance of this trinuclear Molybdenum compounds continue can be improved by combining them with amines and / or phenolic compounds are used to induce the soot viscosity increase especially in aged oils to control.

Accordingly, the present invention includes a diesel engine lubricant composition comprising base material, dispersant and antioxidant comprising an oil-soluble trinuclear organomolybdenum compound having the generic formula: Mo ₃ S _x - (Q) (I) wherein x is 4 to 10, preferably 7, and Q is a core group which may be a ligand and at least one other compound selected from phenolic and amine compounds.

The compositions of the present invention are those comprising a major amount of lubricating oil useful as a base material for use in crankcase lubricants, particularly in a diesel engine crankcase. Natural or synthetic lubricating oils with a kinematic viscosity of 3.5 to 25 mm ² / s (cSt) at 100 ° C thus represent a greater proportion of the lubricant compositions.

The Properties of the maintenance of the dispersing effect are improved according to the invention, by putting in the crankcase lubricant an added oil-soluble organomolybdenum compound and at least one other compound selected from phenolic and aminic Connection is included.

• (1) Kohlenwasserstoffsubstituenten, d. h. aliphatische (beispielsweise Alkyl oder Alkenyl), alicyclische (beispielsweise Cycloalkyl oder Cycloalkenyl), aromatisch, aliphatisch und alicyclisch substituierte aromatische Kerne und dergleichen sowie cyclische Substituenten, bei denen der Ring durch einen weiteren Anteil des Liganden geschlossen wird (das heißt, dass irgendwelche zwei angegebene Substituenten zusammen eine alicyclische Gruppe bilden können);
• (2) substituierte Kohlenwasserstoffsubstituenten, d. h. jene, die Nicht-Kohlenwasserstoffgruppen enthalten, die im Kontext dieser Erfindung den vorwiegenden Kohlenwasserstoffcharakter des Substituenten nicht ändern. Fachleute werden geeignete Gruppen kennen (z. B. Halogen (insbesondere Chlor), Amino, Alkoxyl, Mercapto Alkylmercapto, Nitro, Nitroso, Sulfoxy, usw.), und
• (3) Heterosubstituenten, d. h. Substituenten, die, obwohl sie im Kontext dieser Erfindung vorwiegend Kohlenwasserstoffcharakter haben, von Kohlenstoff verschiedene Atome in einer Kette oder einem Ring enthalten, der ansonsten aus Kohlenstoffatomen zusammengesetzt ist.

The trinuclear molybdenum compounds of the formula (I) Mo ₃ S _x - (Q) (I), where x is 4 to 10, preferably 7, and Q is a core group, are relatively new and claimed and described in our previously published US-A-5,906,968. The disclosure of the structure, manufacture and properties of the trinuclear molybdenum compounds disclosed in this earlier patent is incorporated herein by reference. In these compounds, the core group (Q) may be a ligand which can render the organomolybdenum compound of the formula (I) oil-soluble and ensure that the molybdenum compound is substantially charge-neutral. The core group (Q) is generally associated with suitable ligands such as L _y , where L is the ligand and y is a sufficient number, type and charge sufficient to render the compound of formula (I) oil-soluble and charge to neutralize on the compound of formula (I) as a whole. More specifically, the trinuclear molybdenum compound used in the compositions of the invention may be represented by the formula (II) Mo ₃ S _x L _y (II) be reproduced. The ligands "L" are suitably dihydrocarbyl dithiocarbamates having the structure (-S ₂ CNR ₂ ) in which the hydrocarbon groups, R ₂ , impart oil solubility to the molybdenum compound. In this case, the term "hydrocarbon" refers to a substituent having carbon atoms attached directly to the rest of the ligand, and has predominantly hydrocarbon character within the context of this invention. Such substituents include the following:

• (1) Hydrocarbon substituents, ie aliphatic (for example alkyl or alkenyl), alicyclic (for example cycloalkyl or cycloalkenyl), aromatic, aliphatic and alicyclic substituted aromatic nuclei and the like, and cyclic substituents in which the ring is closed by a further portion of the ligand (the means that any two substituents given together may form an alicyclic group);
• (2) substituted hydrocarbyl substituents, ie, those containing non-hydrocarbon groups which, in the context of this invention, do not alter the predominantly hydrocarbon character of the substituent. Those skilled in the art will be aware of suitable groups (eg, halogen (especially chlorine), amino, alkoxy, mercapto alkylmercapto, nitro, nitroso, sulfoxy, etc.), and
• (3) Heterosubstituents, that is, substituents which, while predominantly hydrocarbon in character within the context of this invention, contain atoms other than carbon in a chain or ring otherwise composed of carbon atoms.

The Hydrocarbon groups are predominantly alkyl (e.g., where the carbon atom attached to the residues of the ligand "L" primary, secondary or tertiary is), aryl, substituted aryl and / or ether groups.

Important is that the hydrocarbon groups of the ligand sufficient Number of carbon atoms to the compound (I) soluble in the oil or to be made dispersible to the containing the ligands, trinuclear organomolybdenum is added. The total number of all hydrocarbon groups the ligands of the organomolybdenum compounds carbon atoms present is suitably at least 21, preferably at least 25, in particular at least 30 and particularly preferred at least 35, d. H. usually z. B. 21 to 800. The number of Carbon atoms in each hydrocarbon group is suitably generally in the range of 1 to 100, preferably 1 to 40 and especially 3 to 20.

The Antioxidant in the compositions of the invention includes at least one other compound selected from phenolic compound and aminic compound. Of the phenolic compounds hindered phenols are preferred.

Examples of such phenolic compounds include, but are not limited to:
4,4-methylenebis (2,6-di-tert-butylphenol),
4,4'-bis (2,6-di-tert-butyl phenol)
4,4'-bis (2-methyl-6-tert-butylphenol),
2,2'-methylenebis (4-ethyl-6-tert-butylphenol),
2,2'-methylenebis (4-methyl-6-butylphenol),
4,4'-butylidenebis (3-methyl-6-tert-butylphenol),
4,4'-isopropylidenebis (2,6-di-tert-butylphenol),
2,2'-methylenebis (4-methyl-6-nonylphenol),
2,2'-Isobutylidenbis (4,6-dimethylphenol),
2,2'-methylenebis (4-methyl-6-cyclohexylphenol),
2,6-di-tert-butyl-4-methylphenol,
2,6-di-tert-butyl-4-ethylphenol and
2,4-dimethyl-6-tert-butylphenol.

Specific hindered phenols which are preferred as antioxidants can be represented by the following generic formulas (III) to (IV) in which R ₁ , R ₂ and R _{3 represent} the same or different alkyl groups having 3 to 9 carbon atoms, and x and y are integers from 1 to 4.

Suitable aminic compounds for use in the compositions of this invention are diarylamines, arylnaphthylamines and alkyl derivatives of diarylamines and the arylnaphthylamines. Preferred amino antioxidants are represented by the formulas (VII) and (VIII) in which each of R ₄ and R _{5 is} a hydrogen atom or are the same or different alkyl groups having 1 to 8 carbon atoms.

Specific examples of the amine compounds that can be used in the compositions of the invention include, among others:
Monoalkyldiphenylamine such. Monooctyldiphenylamine and monononyldiphenylamine, dialkyldiphenylamines such as 4,4'-dibutyldiphenylamine, 4,4'-dipentyldiphenylamine, 4,4'-dihexyldiphenylamine, 4,4'-diheptyldiphenylamine, 4,4'-dioctyldiphenylamine and 4,4'-dinonyldiphenylamine ; Polyalkyldiphenylamines such as tetrabutyldiphenylamine, tetrahexyldiphenylamine, tetraoctyldiphenylamine and tetranonyldiphenylamine; the naphthylamines such as α-naphthylamine and phenyl-α-naphthylamine; Butylphenyl-α-naphthylamine, pentylphenyl-α-naphthylamine, hexylphenyl-α-naphthylamine, heptylphenyl-α-naphthylamine, octylphenyl-α-naphthylamine and nonylphenyl-α-naphthylamine. Of these, preferred are dialkyldiphenylamine and naphthylamines.

The Antioxidant that combines the organomolybdenum compound comprising phenolic and / or aminic compound generally a minor one Component of the total lubricant composition. The organomolybdenum compound usually represents, for example, 0.05 to 5.00 wt .-% of the total Composition, preferably 0.05 to 2.0 wt .-% and in particular 0.1 to 0.7 wt%, d. H. the molybdenum metal is suitable in an amount of 25 to 2500 ppm, especially 50 to 1000 ppm and especially 100 to 700 ppm present, and the phenolic and / or aminic compounds 0.10 to 3.0 wt .-% of the total Composition.

It has also been found that when the weight ratio of Organomolybdenum compound too the phenolic and / or aminic compound in the antioxidant in the range of 80:20 to 20:80, optimum retention of the dispersing effect achieved by these combined antioxidants of the present can.

It It is particularly preferred that the antioxidant be in addition to the organomolybdenum compound a mixture of the above phenols (III) and (IV) and the diarylamine (V) in a weight ratio in the range of 80:10:10 to 40:20:40, preferably in the Usually 75:15:15 respectively.

The Antioxidants can optionally with a carrier liquid be combined in the form of a concentrate. The concentration of combined antioxidants in the concentrate may be from 1 to 80% by weight vary and is preferably in the range of 5 to 10 wt .-%.

The antioxidant combination of the invention can be used with any of the conventional dispersants heretofore used in the lubricant compositions. Examples of such dispersants include, inter alia, the polyalkylene succinimides, Mannich condensation products of polyalkylphenol-formaldehyde polyamine and borated derivatives thereof. However, it is preferred to use ashless dispersants such as the ashless succinimides, especially the polyisobutenyl succinimides of a polyamine such as e.g. Tetraethylenepentamine or its homologues, ashless benzylamine dispersants and ashless ester dispersants. The dispersants are generally used in the compositions of the invention in an amount ranging from 2 to 10% by weight, preferably 4 used to 8 wt .-%, based on the total weight of the lubricant composition.

These Lubricating compositions can generally include additives commonly used in lubricating oils especially in crankcase lubricants such as anti-wear agents, Detergents, rust inhibitors, viscosity index improvers, extreme pressure agents, Friction modifiers, corrosion inhibitors, emulsifying aids, Pour point depressants, antifoaming agents and the like.

One Feature of the lubricant compositions of the invention is that the presence of trinuclear organomolybdenum compounds in combination with phenolic and / or aminic compound as Antioxidant unexpected improvement of oxidation control, viscosity increase control and maintaining the dispersing action on compositions, containing only one of these antioxidants used alone becomes.

The The present invention will be described with reference to the following examples explained in more detail.

EXAMPLES

General procedure:

A Range of test oils was produced. These oils were then tested in a test bed oxidation test, the at 165 ° C under a mixed nitrogen / air stream with 40 ppm iron Added ferric acetylacetonate was carried out as a catalyst. The flow rates of nitrogen and air were to 500 ml / min or 350 ml / min regulated.

The remaining dispersing effect of the test oil after 32 hours in the test-bench oxidation test then by using a dispersant effect test with GM 6.2L carbon black loaded Base material determined in which the soot dispersing action of a used oil the viscosity ratio of diluted test oil was detected in the presence and absence of carbon black; the lower The relationship the better was the dispersing effect. The test oil was with a soot-laden 600 SN base material (3.5 to 4.5% by weight carbon black) from the GM 6.2L engine in relationship of 25:75 (by weight) mixed, and the kinematic viscosity the mixture of test oil and fresh base oil (Soot-free 600 SN) in the same ratio (25:75) at 100 ° C was also measured. The dispersing effect of the fresh oil was also detected using the same procedure.

In these tests, the following commercial materials were used:
Irganox ^® L57 is an octylated / butylated diphenylamine (ex Ciba Geigy)
Irganox ^® L101 is a high molecular weight phenolic antioxidant (by Ciba Geigy)
Irganox ^® L115 and Irganox ^® 1035 are high molecular weight phenolic antioxidants with a thioether group (by Ciba Geigy)
Irganox L06 is an alkylated phenyl-α-naphthylamine (by Ciba Geigy)
Irganox ^® L135 is a high molecular weight phenolic antioxidant (by Ciba Geigy)
Irganox ^® L150 is a mixture of alkylated diphenylamine, phenolic antioxidant and phenolic antioxidant with thioether group (by Ciba Geigy)
Paranox ^® 106 is a polyisobutenyl dispersant (of Infenium, Linden, NJ, USA)
Molyvan ^® 822 is a dinuclear molybdenum (from RT Vanderbilt Co.).

Examples A to E

The Compositions of the test oils A to E are shown in the following table:

Table 1

The Characteristics of fresh test oils (A to E) are shown in the following Table 2.

Table 2

The Table 3 below shows the characteristics of the used oils (A to E) after the oxidation test.

Table 3

Out the above results show that in the compositions, the trinuclear invention molybdenum compound contained, the viscosity control and the ability the composition for maintaining the dispersing effect clearly were improved.

Examples F to R

Under Using the same methods and materials as above the General Procedure for Examples (A to E) described the following further tests with additional test oils carried out.

The Compositions of the test oils used in Examples (F to R) are shown in the following Table 4.

Claims (10)

A method of controlling the carbon black-induced viscosity of diesel engine lubricant composition comprising base material and dispersant by adding an effective amount of antioxidant, characterized in that the antioxidant is an oil-soluble trinuclear organomolybdenum compound having the generic formula: Mo ₃ S _x - (Q) (I), wherein x is 4 to 10 and Q is a core group which may be a ligand and comprises at least one other compound selected from phenolic and amine compounds. The method of claim 1, wherein the composition comprises a major amount of natural or synthetic lubricating oil having a kinematic viscosity of 3.5 to 25 mm ² / s (cSt). Method according to one of the preceding claims, in which the trinuclear molybdenum compounds have the formula (I) Mo ₃ S _x - (Q) (I), where x is 7 and Q is a core group. Method according to one of the preceding claims, in the core group Q is a ligand containing the organomolybdenum compound of the formula (I) make oil soluble and ensure can that molybdenum compounds is essentially charge neutral. A method according to any one of the preceding claims, wherein the phenolic compound is a hindered phenol. A process according to any one of the preceding claims wherein the amine compound is selected from one or more of diarylamines, arylnaphthylamines and alkyl derivatives of diarylamines and the arylnaphthylamines of the following formulas (VII) or (VIII) wherein each of R ₄ and R ₅ is a hydrogen atom or represents the same or different alkyl groups having 1 to 8 carbon atoms

Method according to one of the preceding claims, in the antioxidant, the trinuclear organomolybdenum compound and at least one further compound selected from phenolic and / or aminic Compound includes, a minor one Component of the total lubricant composition forms. Method according to one of the preceding claims, in the antioxidant, the trinuclear organomolybdenum compound and an amine compound comprises a minor component the entire lubricant composition forms. Method according to one of the preceding claims, in the trinuclear organomolybdenum compound in the composition in an amount of 0.05 to 5.00 wt .-% of entire composition is present. Method according to one of the preceding claims, in the amount of phenolic and / or aminic compounds, which are present in the composition, 0.10 to 3.0 wt .-% of total composition is.