RU2427615C2 - Lubricating oil composition - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: in order to reduce clogging of a diesel filter with solid particles, the lubricating oil composition contains one or more magnesium-containing detergent additives selected from magnesium-salicylate detergent additives, magnesium-phenol detergent additives and magnesium-sulphonate detergent additives. The composition preferably contains sulphated ash in amount of not more than 1.0 wt % and phosphorus in amount ranging from 0.04 to 0.1 wt % relative to the total weight of the composition of the lubricating oil. The magnesium-containing additives have total base number (TBN) measured in accordance with ISO 3771 ranging from 30 to 600 mg KOH/g.

EFFECT: reduced clogging of a diesel engine with solid particles.

14 cl, 2 tbl, 4 ex

Description

The present invention relates to a lubricating oil composition, in particular to a lubricating oil composition suitable for lubricating internal combustion engines.

Given the harmful effects that sulfated ash, sulfur, and phosphorus contained in a lubricating oil composition can have on vehicles for pre-treatment of exhaust gases from vehicles, such as diesel particulate filters (DPF), there is a trend towards reduced lubricant oil compositions sulfated ash, sulfur, and phosphorus (i.e., so-called low SAPS lubricating oil compositions).

The phosphorus content can usually be reduced by reducing the amount of zinc dithiophosphates contained in anti-wear additives in lubricating oil compositions.

Sulfur levels in lubricating oil compositions can be reduced by using low-sulfur base oils and reducing the amount of sulfur-containing additives used in them.

Sulphated ash is the total weight content of the residue remaining after burning the lubricating oil composition and subsequent treatment with sulfuric acid and drying to constant weight. The sulfated ash content in the lubricating oil composition corresponds to the total metal content in it. Sulphated ash can be easily measured in accordance with ASTM D874.

The main sources of sulfated ash in a lubricating oil composition are usually metal-containing detergents and anti-wear additives based on zinc dithiophosphate.

Sulfated ash deposits can clog the diesel particulate filter (DPF) on vehicles, thereby shortening the filter's life, increasing back pressure in the vehicle's engine, and leading to increased fuel consumption.

The tendency of diesel particulate filters to clogging can be measured using tests such as the Volkswagen diesel particulate filter test (VW). This tough diesel particulate filter test is part 52195 of the completed VW factory specification.

In order to minimize problems with the diesel particulate filter of vehicles in existing low SAPS lubricant oil compositions, sulfated ash levels and therefore detergent levels are low.

However, reducing the amount of additives in the lubricating oil composition in order to reduce its sulfated ash content may have a detrimental effect on the basicity of the lubricating oil composition.

Total Base Number (TBN) is a measure of how well a lubricating oil composition can neutralize acidic combustion / oxidation by-products, and is defined as the amount of acid expressed in the equivalent milligrams of potassium hydroxide needed to neutralize all the major constituents present in 1 gram of sample lubricating oil compositions (test methods include, for example, ISO 3771, ASTM D-2896 and ASTM D-4739).

In order to be able to control the corrosive wear of the engine from acidic combustion / oxidation by-products, it is desirable that the TBN composition has a high TBN. Additives to the lubricating oil composition are the main source of alkalinity (TBN) and allow, for example, control deposits on piston rings and cylinder liners.

Thus, metal detergent additives are the main source of TBN in crankcase lubricant compositions.

As a result, the initial TBN (i.e., TBN of fresh, unused lubricating oil compositions) of low SAPS lubricating oil compositions tends to be lower than the TBN of lubricating oil compositions with higher concentrations of sulfated ash, sulfur and / or phosphorus.

For this reason, it is highly desirable to be able to reduce the harmful clogging of the filter block with sulfated ash to trap solid particles on a diesel engine without lowering the basicity of the lubricating oil composition.

US-A-6114288 discloses lubricating oil compositions for internal combustion engines with sulfur contents ranging from 0.8 to 1.8% by weight according to JISK 2272, which include a base oil, specific zinc dialkyldithiophosphates and a metal-containing detergent selected from ( i) calcium alkyl salicylate and (ii) a mixture of calcium alkyl salicylate with magnesium alkyl salicylate.

Although examples of US-A-6114288 test the wear properties of lubricating oil compositions including various alkaline earth metal detergents, such as calcium sulfonate, magnesium sulfonate, calcium salicylate and magnesium salicylate, it should be noted that US-A-6114288 is in no way does not apply to the properties of said lubricating oil compositions in tests on diesel particulate filters and, in particular, in a test of a diesel particulate filter VW.

US2002 / 0019320 A1 describes lubricating oil compositions having a low sulfated ash content, low phosphorus content and low sulfur content. It is claimed that these lubricating oil compositions have good detergent properties at high temperatures.

Detergents used in US-2002/0019320 A1 lubricating oil compositions are additives containing an organic acid salt with a metal selected from the group consisting of an unsulfurized alkali or alkaline earth metal salt with alkyl salicylic acid having TBN from 10 to 350 mg KOH / g, an unsulfurized salt of an alkali or alkaline earth metal with an alkyl phenol derivative having a Mannich base structure in an amount of from 0.1 to 1% by weight, based on sulfated ash.

Although various alkaline earth metal detergents are used in Examples US-2002/0019320 A1, it should be noted that calcium is the preferred alkaline earth metal and that none of the US-2002/0019320 A1 lubricating oil compositions are actually tested on diesel particulate filters and in particular using the VW diesel particulate filter test.

US-2004/0127371 A1 discloses a means for reducing the amount of metal-containing compounds in lubricating oil compositions so that these compositions are more suitable for use in engines equipped with particulate filters.

In US-2004/0127371 A1, it is stated that the amount of detergent needed to neutralize the mineral acids generated during combustion and to reduce engine corrosion can be reduced in engines using low-sulfur fuels.

Accordingly, US 2004/0127371 describes a lubricating oil composition for use in a compression ignition internal combustion engine (diesel engine) running on diesel fuel with a sulfur content of less than 50 ppm, and this lubricating oil composition includes oil as a main component with the viscosity necessary for lubrication and at least one metal-containing additive, wherein said lubricating oil composition has a total ash content of less than 1.0 wt.% based on the total weight of the compositions and lubricating oil.

It should be noted that the approach used in US 2004/0127371 reduces the role of TBN, which is put in the first place in the lubricating oil composition by reducing the formation of acidic substances.

However, US-2004/0127371 does not report anything about how to reduce the harmful effect of clogging with sulfated ash diesel filter units to trap solid particles without having to sacrifice the alkalinity of the lubricating oil composition.

US 2004/017260 A1 discusses the accumulation of ash from metal-containing detergent additives and zinc dialkyl dithiophosphate additives in exhaust gas pre-treatment devices and the resulting deterioration in washing and anti-wear properties if this problem is solved by reducing the content of these additives in the lubricating oil composition.

US 2004/017260 A1 discloses a means for compensating for the aforementioned deterioration by mixing specific ashless dispersants and phosphorus-containing ashless antiwear additives in specific amounts as an alternative to the fatty amide, while reducing the amount of zinc dialkyldithiophosphate and metal detergent additives.

However, in an unexpected manner, in the present invention, it was found that at a given sulfated ash content, the use of magnesium-containing detergents in the lubricating oil composition leads to improved performance in tests on diesel particulate filters or, in other words, reduces clogging of filters compared to what occurs when using calcium detergent additives in the composition.

Accordingly, with these characteristics in tests on diesel particulate filters, it is now unexpectedly possible to provide the required alkalinity of the lubricating oil composition using larger amounts of magnesium-containing detergent additives in lubricating oil compositions compared to a lubricating oil composition with a calcium-containing detergent additive and / or using a magnesium-containing a detergent with a higher TBN compared to a calcium detergent.

Thus, the disadvantages associated with attempts to achieve a balance between the alkaline properties of the lubricating oil composition and reducing the clogging of the diesel engine with solid particles can be eliminated by using magnesium-containing detergents.

The present invention provides the use in a lubricating oil composition containing a base oil of one or more magnesium-containing additives in order to reduce clogging of a diesel particulate filter.

In particular, the present invention provides the use in a lubricating oil composition containing a base oil of one or more magnesium-containing additives in order to reduce clogging of a diesel particulate filter, in particular compared to the use of calcium-containing additives in this composition.

The clogging of the diesel particulate filter is mainly measured using the VW diesel particulate filter test.

Used in the present invention, one or more magnesium-containing detergents are selected mainly from detergents based on magnesium salicylate, magnesium phenolate and magnesium sulfonate. Detergents based on magnesium salicylate and magnesium phenolate are especially preferred.

In order to maintain the total sulfated ash content in the lubricating oil composition, preferably not more than 1.0 wt.%, More preferably not more than 0.9 wt.% And most preferably not more than 0.8 wt.% based on the total weight of the lubricating oil composition, these one or more magnesium-containing detergent additives are used predominantly in a total amount of not more than 0.2 wt.% based on the magnesium content, more preferably in a total amount of not more than 0.17 wt.% based on content mage Ia and most preferably in a total amount of not more than 0.15 wt.% based on the magnesium content in relation to the total weight of the lubricating oil composition.

The magnesium-containing detergents used in the present invention can be either neutral or have high alkalinity. The expression “with increased alkalinity” is equivalent to the expressions “alkaline”, “super-alkaline”, “hyper-alkaline” and “salt with a high metal content”. These magnesium-containing detergents contain an excess of metal compared to the amount of metal that would be present in accordance with the stoichiometry of the metal and the acidic organic compound that has reacted with the metal. Methods for preparing such neutral or alkali metal salts are well known in the art. Neutral salts can be obtained by heating a solution of an acidic organic compound in mineral oil with a stoichiometrically equivalent amount of a metal-containing neutralizing agent such as an oxide, hydroxide, carbonate, bicarbonate or metal sulfide at a temperature above 50 ° C, followed by filtration of the resulting mass. Alkaline salts are prepared in a similar manner except that a stoichiometric excess of metal is used. Magnesium-containing detergents with increased alkalinity are preferably used.

Detergents can be characterized by their total base number (TBN). Preferably, each total alkaline number of one or more magnesium-containing additives, measured in accordance with ISO 3771, is independently in the range of 30 to 600 mg KOH / g, more preferably in the range of 30 to 450 mg KOH / g, and most preferably in the range 30 to 350 mg KOH / g.

Magnesium salicylates suitable for successful use can be either substituted or unsubstituted. Suitable substituents include aliphatic groups containing from 1 to 40 carbon atoms and possibly containing one or more oxygen and / or nitrogen atoms, and hydroxyl groups. Preferred substituents are alkyl groups containing from 6 to 30 carbon atoms, preferably from 12 to 20 carbon atoms. Preferably, the substituents are linear. Magnesium salicylates may contain from 1 to 4 substituents, preferably in the range from 1 to 3, and most preferably 1 or 2 substituents. Most preferably, the magnesium salicylates are substituted with one linear alkyl substituent containing from 14 to 18 carbon atoms.

Typically, monoalkylsalicylic acids are prepared by alkylation of phenol followed by carboxylation. In this case, a small amount (usually not more than 20 mol.%) Of dialkyl salicylate and unsubstituted salicylate may be contained in monoalkyl salicylate.

Magnesium salicylates suitable for use in the present invention are commercially available. For example, a commercial magnesium salicylate is magnesium salicylate sold by Unfineum under the trade name "Unfineum C9012".

The method by which magnesium salicylates can be obtained is described in US-A-4,627,928.

EP-A-1195427 describes magnesium phenolates and methods for producing such detergent additives.

EP-A-1195427, WO-A-97/14774 and US-A-5534168 describe magnesium sulfonate and methods for producing magnesium alkali sulfonates.

Magnesium phenolates and magnesium sulfonates suitable for use in the present invention are commercially available. For example, commercial magnesium sulfonate is supplied by Unfineum under the trade name "Unfineum C9340".

The initial TBN value, measured in accordance with ISO 3771, of the lubricating oil composition used in the present invention is preferably in the range of 4.0 to 12.0 mg KOH / g, more preferably in the range of 6.0 to 11.0 mg KOH / g, even more preferably in the range of 6.0 to 10.0 mg KOH / g, and most preferably in the range of 6.0 to 9.5 mg KOH / g.

The sulfated ash content in the lubricating oil composition is preferably not more than 1.0 wt.%, More preferably not more than 0.9 wt.% And most preferably not more than 0.8 wt.% With respect to the total weight of the lubricating oil composition.

The sulfur content in the lubricating oil composition is preferably not more than 1.2 wt.%, More preferably not more than 0.8 wt.% And most preferably not more than 0.3 wt.% With respect to the total weight of the lubricating oil composition.

Preferred lubricating oil compositions in the present invention are characterized by one or more of the following features:

(i) more than 0.04 wt.% phosphorus;

(ii) more than 0.045 wt.% phosphorus;

(iii) not less than 0.04 wt.% phosphorus;

(iv) less than 0.09 wt.% phosphorus;

(v) not more than 0.10 wt.% phosphorus;

(vi) the largest 0.085 wt.% phosphorus;

(vii) not more than 1.0 wt.% sulfated ash;

(viii) not more than 0.9 wt.% sulfated ash;

(ix) not more than 0.8 wt.% sulfated ash;

(x) not more than 1.2 wt.% sulfur;

(xi) not more than 0.8 wt.% sulfur; and

(xii) not more than 0.3 wt.% sulfur, based on the total weight of the lubricating oil composition.

Particularly preferred lubricating oil compositions in the present invention have one or more of the following features:

(A): those having features (i) and (iv); having features (i) and (v); having features (i) and (vi); having features (ii) and (iv); having features (ii) and (v); having features (ii) and (vi); having features (iii) and (iv); having features (iii) and (v) and having features (iii) and (vi);

(B): having features (i), (iv) and (vii); having features (i), (iv) and (viii); having features (i), (iv) and (ix); having features (i), (v) and (vii); having features (i), (v) and (viii); having features (i), (v) and (ix); having features (i), (vi) and (vii); having features (i), (vi) and (viii); having features (i), (vi) and (ix); having features (ii), (iv) and (vii); having features (ii), (iv) and (viii); having features (ii), (iv) and (ix); having features (ii), (v) and (vii); having features (ii), (i) and (viii); having features (ii), (v) and (ix); having features (ii), (vi) and (vii); having features (ii), (vi) and (viii); having features (ii), (vi) and (ix); having features (iii), (iv) and (vii); having features (iii), (iv) and (viii); having features (iii), (iv) and (ix); having features (iii), (v) and (vii); having features (iii), (v) and (viii); having features (iii), (v) and (ix); having features (iii), (vi) and (vii); having features (iii), (vi) and (viii) and having features (iii), (vi) and (ix);

(C): having features (i), (iv) and (x); having features (i), (iv) and (xi); having features (i), (iv) and (xii); having features (i), (v) and (x); having features (i), (v) and (xi); having features (i), (v) and (xii); having features (i), (vi) and (x); having features (i), (vi) and (xi); having features (i), (vi) and (xii); having features (ii), (iv) and (x); having features (ii), (iv) and (xi); having features (ii), (iv) and (xii); having features (ii), (v) and (x); having features (ii), (v) and (xi); having features (ii), (v) and (xii); having features (ii), (vi) and (x); having features (ii), (vi) and (xi); having features (ii), (vi) and (xii); having features (iii), (iv) and (x); having features (iii), (iv) and (xi); having features (iii), (iv) and (xii); having features (iii), (v) and (x); having features (v), (viii) and (x); having features (ii), (v), (ix) and (x); having features (ii), (vi), (vii) and (x): having features (ii), (vi), (viii) and (x); having features (ii), (vi), (ix) and (x); having features (iii), (iv), (vii) and (x); having features (iii), (iv), (viii) and (x); having features (iii), (iv), (ix) and (x); having features (iii), (v), (vii) and (x); having features (iii), (v), (viii) and (x); having features (iii), (v), (ix) and (x); having features (iii), (vi), (vii) and (x); having features (iii), (vi), (viii) and (x); having features (iii), (vi), (ix) and (x); having features (i), (iv), (vii) and (xi); having features (i), (iv), (viii) and (xi); having features (i), (iv), (ix) and (xi); having features (i), (v), (vii) and (xi); having features (i), (v), (viii) and (xi); having features (i), (v), (ix) and (xi); having features (i), (vi), (vii) and (xi); having features (i), (vi), (viii) and (xi); having features (i), (vi), (ix) and (xi); having features (ii), (iv), (vii) and (xi); having features (ii), (iv), (viii) and (xi); having features (ii), (iv), (ix) and (xi); having features (ii), (v), (vii) and (xi); having features (ii), (v), (viii) and (xi); having features (ii), (v), (ix) and (xi); having features (ii), (vi), (vii) and (xi); having features (ii), (vi), (viii) and (xi); having features (ii), (vi), (ix) and (xi); having features (iii), (iv), (vii) and (xi); having features (iii), (iv), (viii) and (xi); having features (iii), (iv), (ix) and (xi); having features (iii), (v), (vii) and (xi); having features (iii), (v), (viii) and (xi); having features (iii), (v), (ix) and (xi); having features (vi), (viii) and (xi); having features (i), (vi), (ix) and (xi); having features (ii), (iv), (vii) and (xi); having features (ii), (iv), (viii) and (xi); having features (ii), (iv), (ix) and (xi); having features (ii), (v), (vii) and (xi); having features (ii), (v), (viii) and (xi); having features (ii), (v), (ix) and (xi); having features (ii), (vi), (vii) and (xi); having features (ii), (vi), (viii) and (xi); having features (ii), (vi), (ix) and (xi); having features (iii), (iv), (vii) and (xi); having features (iii), (iv), (viii) and (xi); having features (iii), (iv), (ix) and (xi); having features (iii), (v), (vii) and (xi); having features (iii), (v), (viii) and (xi); having features (iii), (v), (ix) and (xi); having features (iii), (vi), (vii) and (xi); having features (iii), (vi), (viii) and (xi); having features (iii), (vi), (ix) and (xi); having features (i), (iv), (vii) and (xii); having features (i), (iv), (viii) and (xii); having features (i), (iv), (ix) and (xii); having features (i), (v), (vii) and (xii); having features (i), (v), (viii) and (xii); having features (i), (v), (ix) and (xii); having features (i), (vi), (vii) and (xii); having features (i), (vi), (viii) and (xii); having features (i), (vi), (ix) and (xii); having features (ii), (iv), (vii) and (xii); having features (ii), (iv), (viii) and (xii); having features (ii), (iv), (ix) and (xii); having features (ii), (v), (vii) and (xii); having features (ii), (v), (viii) and (xii); having features (ii), (v), (ix) and (xii); having features (ii), (vi), (vii) and (xii); having features (ii), (vi), (viii) and (xii); having features (ii), (vi), (ix) and (xii); having features (iii), (iv), (vii) and (xii); having features (iii), (iv), (viii) and (xii); having features (iii), (iv), (ix) and (xii); having features (iii), (v), (vii) and (xii); having features (iii), (v), (viii) and (xii); having features (iii), (v), (ix) and (xii); having features (iii), (vi), (vii) and (xii); having features (iii), (vi), (viii) and (xii); and having features (iii), (vi), (ix) and (xii).

The amount of base oil introduced into the lubricating oil composition is preferably from 60 to 92 wt.%, More preferably from 75 to 90 wt.% And most preferably from 75 to 88 wt.% With respect to the total weight of the lubricating composition oils.

There are no particular restrictions on the base oil used in the present invention, and therefore, various conventional well-known mineral and synthetic lubricating oils can be successfully used.

Mineral oils include liquid petroleum oils and paraffinic, naphthenic or mixed paraffin-naphthenic type mineral lubricant treated with a solvent or acid, which can be further refined using hydrotreating and / or dewaxing processes.

Naphthenic base oils have a low viscosity index (VI) (usually 40-80) and a low pour point. Such base oils are obtained from raw materials enriched with naphthenes and low in paraffin content, and they are mainly used as lubricants for which color and color stability are important, and VI and oxidation resistance are of secondary importance.

Paraffin base oils have a higher VI (usually above 95) and a high pour point. Such base oils are derived from paraffin-rich feedstocks and are used as lubricants for which IV and oxidation resistance are important.

The base oils obtained by the Fischer-Tropsch method can be successfully used as the base oil in the lubricating oil composition of the present invention. The base oils obtained by the Fischer-Tropsch method are disclosed in EP-A-776959, EP-A-668342, WO-A-97/21788, WO-00/15736, WO-00/14188, WO-00/14187, WO -00/14183, WO-00/14179, WO-00/08115, WO-99/41332, EP-1029029, WO-01/18156 and WO-01/57166.

Synthetic processes make it possible to build molecules from simpler substances or modify their structure in such a way as to precisely give them the required properties.

Synthetic base oils include hydrocarbon oils such as olefin oligomers (PAO), dibasic esters, polyol esters, and dewaxed paraffin raffinate. Synthetic hydrocarbon base oils sold by the Shell group under the name “XHVI” (trademark) may be used with success. Preferably, the base oil consists of mineral oils and / or synthetic base oils, which, according to measurements in accordance with ASTM D2007, contain more than 80 wt.% Saturated compounds and more preferably more than 90 wt.%.

In addition, it is preferable that the base oil contains less than 1 wt.% And more preferably less than 0.1 wt.% Sulfur, calculated as elemental sulfur and measured in accordance with ASTM D2622, ASTM D4294, ASTM D4927 or ASTM D3120.

Preferably, the viscosity index of the base oil, as measured in accordance with ASTM D2270, is above 80 and more preferably above 120.

Preferably, the lubricating oil composition has a kinematic viscosity ranging from 2 to 80 mm ² / s at 100 ° C, more preferably from 3 to 70 mm ² / s, and most preferably from 4 to 50 mm ² / s.

The lubricating oil composition of the present invention may also, in some cases, include one or more additional additives, such as antioxidants, antiwear additives, additional detergents, dispersants, friction modifiers, viscosity index improvers, depressants, corrosion inhibitors, antifoaming agents and fast sealing agents or agents giving the sealants compatibility.

In one embodiment of the present invention, the lubricating oil composition may contain one or more amine and / or phenolic antioxidant.

Examples of suitable amine antioxidants for successful use include alkylated diphenylamines, phenyl-α-naphthylamines, phenyl-β-naphthylamines, and alkylated α-naphthylamines.

Preferred amine antioxidants include dialkyl diphenylamines such as p, p'-dioctyl-diphenylamine, p, p'-di-α-methylbenzyl-diphenylamine and N-p-butylphenyl-N-p'-octylphenylamine, monoalkyl diphenylamines, such as mono tert-butyl diphenylamine and mono-octyl diphenylamine, bis (dialkylphenyl) amines such as di- (2,4-diethylphenyl) amine and di (2-ethyl-4-nonylphenyl) amine, alkylphenyl-1-naphthylamines, such as octylphenyl-1 naphthylamine and N-tert-dodecylphenyl-1-naphthylamine, 1-naphthylamine, arylnaphthylamines such as phenyl-1-naphthylamine, phenyl-2-naphthylamine, N-hexylphenyl-2-naphth tilamine and N-octylphenyl-2-naphthylamine, phenylenediamines such as N, N'-diisopropyl-p-phenylenediamine and N, N'-diphenyl-p-phenylenediamine, and phenothiazines such as phenothiazine and 3,7-dioctylphenothiazine.

Preferred amine antioxidants include antioxidants, which can be purchased under the following trade names "Sonoflex OD3" (Seiko Kagaku Co.), "Irganox L-57" (Ciba Specialty Chemicals Co.) and phenothiazine (Hodogaya Kagaku Co.).

Examples of phenolic antioxidants that can be used successfully include C ₇ -C ₉ branched alkyl esters of 3,5-bis (1,1-dimethyl-ethyl) -4-hydroxy-benzenepropanoic acid, 2-tert-butylphenol, 2 tert-butyl-4-methylphenol, 2-tert-butyl-5-methylphenol, 2,4-di-tert-butylphenol, 2,4-dimethyl-6-tert-butylphenol, 2-tert-butyl-4-methoxyphenol 3-tert-butyl-4-methoxyphenol, 2,5-di-tert-butylhydrochion, 2,6-di-tert-butyl-4-alkylphenols, such as 2,6-di-tert-butylphenol, 2,6 di-tert-butyl-4-methylphenol and 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-alkoxyphenols, so such as 2,6-di-tert-butyl-4-methoxyphenol and 2,6-di-tert-butyl-4-ethoxyphenol, 3,5-di-tert-butyl-4-hydroxybenzyl mercaptooctyl acetate, alkyl-3- (3 , 5-di-tert-butyl-4-hydroxyphenyl) propionates, such as n-octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, n-butyl-3- (3,5 di-tert-butyl-4-hydroxyphenyl) propionate and 2 ethylhexyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,6-di-tert-butyl-α-dimethylamino-p -cresol, 2,2'-methylene bis (4-alkyl-6-tert-butylphenol) such as 2,2'-methylenebis (4-methyl-6-tert-butylphenol), and 2,2-methylene bis (4-ethyl-6-tert-butylphenol) (bisphenols such as 4,4'-bu ylidene bis (3-methyl-6-tert-butylphenol), 4,4'-methylene bis (2,6-di-tert-butylphenol), 4,4'-bis (2,6-di-tert- butylphenol), 2,2- (di-p-hydroxyphenyl) propane, 2,2-bis (3,5-di-tert-butyl-4-hydroxyphenyl) propane, 4,4'-cyclohexylidene bis (2,6 tert-butylphenol), hexamethylene glycol bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], triethylene glycol bis [3- (3-tert-butyl-4-hydroxy-5-methylphenyl ) propionate], 2,2'-thio [diethyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 3,9-bis {1,1-dimethyl-2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl) 2,4,8,10-tetraoxaspiro [5.5] undecane}, 4,4'-thiobis (3-methyl-6-tr et-butylphenol) and 2,2'-thio-bis (4,6-di-tert-butylresorcinol), polyphenols such as tetrakis [methylene-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di- tert-butyl-4-hydroxybenzyl) benzene, glycol ester of bis [3,3'-bis (4'-hydroxy-3'-tert-butylphenyl) butyric acid, 2- (3 ', 5'-di-tert-butyl -4-hydroxyphenyl) methyl-4- (2 ", 4" -di-tert-butyl-3 "-hydroxyphenyl) methyl-6-tert-butylphenol and 2,6-bis (2'-hydroxy-3'-tert -butyl-5'-methylbenzyl) -4-methylphenol, and the condensation products of p-tert-butylphenol-formaldehyde and p-t ret-butylphenol acetaldehyde.

Preferred phenolic antioxidants include antioxidants that are commercially available under the following trade names: Irganox L-135 (Ciba Specialty Chemicals Co.), Anteeji DBH (Kawaguchi Kagaku Co.,), Yoshinox SS (Yoshitomi Seiyaku Co.), Antage W-400 (Kawaguchi Kagaku Co.), Antage W-500 (Kawaguchi Kagaku Co.), Antage W-300 (Kawaguchi Kagaku Co.), Ionox 220AH (Shell Japan Co.), bisphenol A manufactured by Shell Japan Co., Irganox L109 (Ciba Specialty Chemicals Co.), Tominox 917 (Yoshitomi Seiyaku Co.), Irganox L115 (Ciba Specialty Chemicals Co.), Sumilizer GA80 "(Sumitomo Kagaku)," Antage RC "(Kawaguchi Kagaku Co.)," Irganox L101 "(Ciba Specialty Chemicals Co.)," Yoshinox 930 "(Yoshitomi Seiyaku Co.)," Ionox 330 "(Shell Japan Co .).

The lubricating oil composition may include mixtures of one or more phenolic antioxidants with one or more amine antioxidants.

In one preferred embodiment of the present invention, the lubricating oil composition may include one or more antiwear additives.

Suitable antiwear additives include molybdenum-containing compounds, boron-containing compounds and zinc-containing compounds.

Examples of such molybdenum-containing compounds can advantageously include molybdenum dithiocarbamates, molybdenum ternary compounds, for example those described in WO-A-98/26030, molybdenum sulfides and molybdenum dithiophosphate.

Said molybdenum-containing antiwear additives can be successfully added to the lubricating oil composition in amounts of from 0.1 to 3.0 wt.% With respect to the total weight of the lubricating oil composition.

Suitable boron compounds for successful use include boric acid esters, boronated fatty amines, boronated epoxides, alkali metal borates (or mixtures of alkali metals or alkaline earth metals) and boronated metal salts with increased alkalinity.

These boron-containing antiwear additives can be successfully added to the lubricating oil composition in amounts ranging from 0.1 to 3.0 wt.% With respect to the total weight of the lubricating oil composition.

Preferred zinc-containing anti-wear additives are one or more zinc dithiophosphates selected from dialkyl, diaryl and alkylaryl zinc dithiophosphates.

Zinc dithiophosphate is an additive well known in the art and can best be represented by the general formula

where R ² -R ⁵ may be the same or different and each of them represents a primary alkyl group containing from 1 to 20 carbon atoms, preferably from 3 to 12 carbon atoms, a secondary alkyl group containing from 3 to 20 carbon atoms, preferably from 3 to 12 carbon atoms, an aryl group or an aryl group substituted with an alkyl group, this alkyl substituent containing from 1 to 20 carbon atoms, preferably from 3 to 18 carbon atoms.

Zinc dithiophosphate compounds in which all R ² -R ⁵ are different from each other, can be used on their own or in a mixture with other zinc dithiophosphate compounds in which all R ² -R ⁵ are the same.

Preferably, the zinc dithiophosphates used in the invention are zinc dithiophosphates dialkyls.

Examples of suitable zinc dithiophosphates that are commercially available include zinc dithiophosphates, which can be obtained from Lubrizol Corporation under the trade names "Lz 1097" and "Lz 1395", zinc dithiophosphates, which can be obtained from Chevron Oronite under the trade names "OLOA 267 "and" OLOA 269R "and zinc dithiophosphate, which can be obtained from Ethyl under the trade name" HITEC 7197 "; zinc dithiophosphates, such as those that can be obtained from Lubrizol Corporation under the trade names "Lz 677A", "Lz 1095" and "Lz 1371", such as that which can be obtained from Chevron Oronite under the trade name "OLOA 262" and , one that can be obtained from Ethyl under the trade name "HITEC 7169", and zinc dithiophosphates, such as those that can be obtained from Lubrizol Corporation under the trade names "Lz 1370" and "Lz 1373", and one that can be obtained from Chevron Oronite under the trade name "OLOA 260".

Preferably, the lubricating oil composition contains zinc dithiophosphate in the range from 0.4 to 1.0 wt.%, More preferably in the range from 0.4 to 0.9 wt.% And most preferably in the range from 0.45 to 0, 8 wt.% With respect to the total weight of the lubricating oil composition.

The total amount of phosphorus in the lubricating oil composition is preferably in the range from 0.04 to 0.1 wt.%, More preferably in the range from 0.04 to 0.09 wt.% And most preferably in the range from 0.045 to 0.085 wt.% based on the total weight of the lubricating oil composition.

Additional detergent additives that can be successfully used in the lubricating oil composition include one or more calcium detergent additives selected from calcium salicylates, calcium phenolates and calcium sulfonates.

Calcium-containing detergents can be either neutral or have high alkalinity. Preferably, the total alkaline number of these calcium detergent additives, measured in accordance with ISO 3771, is in the range of 30 to 600 mg KOH / g, more preferably in the range of 30 to 450 mg KOH / g, and most preferably in the range of 30 to 350 mg KOH / g

Examples of commercial calcium detergents include calcium salicylates, which can be obtained from Infineum under the trade names "Infineum M 7101", "Infineum M 7102" and "Infineum M 7105".

In order to prevent calcium-containing detergents from adversely affecting diesel particulate filters of internal combustion engines, it is preferable that the total amount of said one or more calcium-containing detergents is not more than 0.12 wt.% Based on calcium, more preferably so that this total amount is not more than 0.08 wt.% calculated on the calcium content and most preferably this total amount is not more than 0.05 wt.% calculated on the calcium content eniyu the total weight of the lubricating oil composition.

The lubricating oil composition may include an ashless dispersant, which is advantageously mixed in amounts of 5 to 15% by weight of the total weight of the lubricating oil composition.

Examples of suitable dispersants include polyalkenyl succinimides and polyalkenyl succinic acid esters disclosed in Japanese Patent Nos. 1367796, 1667140, 1302811 and 1743435. Preferred dispersants include boron succinimides.

Friction modifiers that can be used successfully include fatty acid esters and fatty acid amides.

The total amount of friction modifiers added to the lubricating oil composition is advantageously in the range from 0.05 to 2.0% by weight of the total weight of the lubricating oil composition.

Examples of viscosity index improvers that can be successfully used in a lubricating oil composition include styrene-butadiene copolymers, star-styrene-isoprene copolymers, polymethacrylate-based copolymers, ethylene-propylene copolymers, and the like, disclosed in Japanese Patents No. 954077 1031507, 1468752, 1764494 and 1751082. Such viscosity index improvers can be used with advantage in amounts ranging from 1 to 20% by weight of the total weight of the lubricating oil composition. Similarly, dispersion type viscosity index improvers, including copolymerized polar monomers containing nitrogen and oxygen atoms in the molecule, can also be used in this composition.

Polymethacrylates, such as those disclosed in Japanese Patents Nos. 1195,542 and 12,64056, can be successfully used in the lubricating oil compositions of the present invention to effectively lower the pour point (depressants).

In addition, compounds such as alkenyl succinic acid or ester fragments thereof, benzotriazole-based compounds and thiodiazole-based compounds can be successfully used in lubricating oil compositions as corrosion inhibitors.

Compounds such as polysiloxanes, dimethylpolysiloxane and polyacrylates can be successfully used in the lubricating oil composition as anti-foaming agents.

Compounds that can be successfully used in a lubricating oil composition as quick sealing agents or agents that give compatibility sealants include, for example, commercially available aromatic esters.

The lubricating oil composition described above can be easily prepared by mixing with the base oil one or more magnesium detergents and, optionally, one or more additional additives, for example those described above.

In the present invention, it was unexpectedly found that lubricating oil compositions comprising one or more magnesium containing detergent additives and a base oil have improved diesel particulate filter test characteristics, in particular in a VW diesel particulate filter test.

In one preferred embodiment of the present invention, the use of said lubricating oil compositions when measured by a VW diesel particulate filter test results in an increase in diesel particulate filter weight of less than 50%.

In another embodiment of the present invention, there is provided a method for improving the performance of a diesel particulate filter test, in particular a VW diesel particulate filter test, which comprises lubricating an internal combustion engine with the lubricating oil composition described above consisting of a base oil and one or more magnesium detergent additives.

Below the present invention is described with reference to the examples given, the purpose of which in no case is to limit the scope of the invention.

EXAMPLES

Compositions

Table 1 shows the tested formulations.

The compositions in Table 1 include traditional antioxidants, anti-foaming agents, dispersants, viscosity modifiers, rapid densification additives, depressants, viscosity index modifiers and zinc dithiophosphate additives.

The magnesium-containing detergent used was an additive purchased from Infineum under the trade name "Infineum C 9012" (TBN 345 mg KOH / g).

The calcium detergents used were those purchased from Infineum under the trade names Infineum M 7101 (TBN 168 mg KOH / g), Infineum M 7102 (TBN 64 mg KOH / g) and Infineum M 7105 (TBN 280 mg KOH / g).

The base oils used in these formulations were Group III base oils obtained from the Shell group under the trade names “XHVI-5.2” and “XHVI-8.2”.

All formulations described in Table 1 were SAE 5W30 viscosity grade oils.

Table 1 Additive (wt.%) Example 1 Example 2 Comparative Example 1 Reference Example 2 Antifoam additive 30 ppm 30 ppm 30 ppm 30 ppm Calcium Salicylate ¹ - - 0.80 1.20 Calcium Salicylate ² - 1.00 - - Calcium Salicylate ³ - - 1,60 1.00 Magnesium Salicylate ⁴ 2.20 1.20 - - Phenolic Antioxidant ⁵ 4.00 4.00 4.00 4.00 Polyisobutensuccinimide
dispersant 8.00 8.00 8.00 8.00 Zinc Dithiophosphates 0.50 0.80 0.50 0.60 Viscosity modifiers 11.50 8.70 12.00 12.00 Other additives ⁶ - 0.70 - 2,50 Base oil ⁷ 73.80 75.60 73.10 70.70 Total one hundred one hundred one hundred one hundred ¹ TBN 168 mg KOH / g, purchased from Infineum under the trade name "Infineum M 7101." ² TBN 64 mg KOH / g, purchased from Infineum under the trade name "Infineum M 7102". ³ TBN 280 mg KOH / g, purchased from Infineum under the trade name "Infineum M 7105". ⁴ TBN 280 mg KOH / g, purchased from Infineum under the trade name "Infineum C 9012". ⁵ Antioxidant, purchased from Ciba Specialty Chemicals under the trade name "IRGANOX L-135". ⁶ A mixture of traditional additives selected from a depressant, a friction modifier, a corrosion inhibitor and additives that promote rapid compaction. ⁷ Mixtures of base oils of group III: XHVI-5.2 and XHVI-8.2, with the exception of comparative example 2, which uses only XHVI-5.2.

VW Diesel Particulate Filter Test (DPF)

The VW Diesel Particulate Filter (DPF) test is part 52195 of the completed VW plant specification.

The experimental methodology used to obtain the results in Table 2 corresponds to a test available in the published literature, which is carried out on a commercial basis by an independent laboratory for testing lubricants, ISP.

The VW diesel particulate filter test measures the percentage increase in the weight of the diesel particulate filter after 250 hours of engine testing.

A test available in the published literature mentions results obtained as the ratio of percent weight increase to percent weight increase on a diesel particulate filter using a control oil for a standard test.

The test limit for one run on a VW engine is set below 50% of the weight increase compared to the control oil mentioned.

Results and discussion

The compositions described in table 1 were tested using the above test and the results obtained therein are included in table 2.

From table 2 it follows that for a given level of sulfated ash, the use of a magnesium-containing detergent as compared to calcium-containing detergents unexpectedly leads to improved performance in a diesel particulate filter test VW to such an extent that the result when using the lubricating oil composition of Example 1 is well below the test limit VW, while the result of the comparative lubricating oil composition of comparative example 1 exceeds the limit of the VW test.

Example 2 shows that the use of a magnesium-containing detergent in combination with a calcium-containing detergent results in a lubricating oil composition with a result lower than the VW test limit.

table 2 results Example 1 Example 2 Comparative Example 1 Reference Example 2 Soap (mmol / kg) 9.0 9.0 9.0 9.1 Original Total Base Number (TBN) (mg KOH / g) 9.50 6.40 7.70 6.70 Total Sulfated Ash (wt.%) (ASTM D874) 0.80 0.61 0.80 0.70 Total sulfur (wt.%) (ASTM D2622) <0.3 0.21 <0.3 <0.3 Total phosphorus (wt.%) (ICP-OES method) <0,049 0,083 0,047 0.059 Ca (wt.%) (ICP-OES method) - 0,025 0,207 0.167 Mg (wt.%) (ICP-OES method) 0.163 0,083 - - The initial kinematic viscosity (100 ° C) (mm ² / s) 12.09 12.21 12.10 12,20 Initial kinematic viscosity (40 ° C) (mm ² / s) 69.50 70.05 69.45 68.16 Shear viscosity of cold start of the engine (-30 ° С) (Pa · s) 64.03 62.58 63.78 59.25 % increase in weight of diesel particulate filter (test on VW filter) 40.00 42.19 63.96 57.80

Claims (14)

1. The use of a lubricating oil composition containing a base oil, one or more magnesium-containing detergent additives selected from magnesium-salicylate detergent additives, magnesium-phenolate detergent additives, magnesium-sulfonate detergent additives to reduce clogging of the diesel particulate filter. 2. The use according to claim 1, in which the lubricating oil composition contains sulfated ash in an amount of not more than 1.0 wt.% With respect to the total weight of the lubricating oil composition. 3. The use according to claim 1, in which one or each of the magnesium-containing detergents has independently TBN (total base number), measured according to ISO 3771, in the range from 30 to 600 mg KOH / g 4. The use according to claim 2, in which one or each of the magnesium-containing detergents has independently TBN (total base number), measured according to ISO 3771, in the range from 30 to 600 mg KOH / g. 5. The use according to any one of claims 1 to 4, in which the base oil is selected from mineral oil and / or synthetic oil. 6. The use according to any one of claims 1 to 4, in which one or more magnesium-containing detergent additives are present in a total amount of not more than 0.2 wt.% Calculated on the magnesium content relative to the total weight of the lubricating oil composition. 7. The use according to claim 5, in which one or more magnesium-containing detergent additives are present in a total amount of not more than 0.2 wt.% Calculated on the magnesium content in relation to the total weight of the lubricating oil composition. 8. The use according to any one of claims 1 to 4 or 7, in which the lubricating oil composition contains phosphorus in the range from 0.04 to 0.1 wt.% With respect to the total weight of the lubricating oil composition. 9. The use according to claim 5, in which the lubricating oil composition contains phosphorus in the range from 0.04 to 0.1 wt.% With respect to the total weight of the lubricating oil composition. 10. The use according to claim 6, in which the lubricating oil composition contains phosphorus in the range from 0.04 to 0.1 wt.% With respect to the total weight of the lubricating oil composition. 11. The use according to any one of claims 1 to 4, 7, 9 or 10, wherein the lubricating oil composition further comprises one or more additives selected from antioxidants, anti-wear additives, additional detergent additives, dispersants, friction modifiers, index improvers viscosity, depressants, corrosion inhibitors, antifoaming agents and quick-tightening agents or agents that give sealants compatibility. 12. The use according to claim 5, in which the lubricating oil composition further comprises one or more additives selected from antioxidants, antiwear additives, additional detergent additives, dispersants, friction modifiers, viscosity index improvers, depressants, corrosion inhibitors, antifoam agents, and fast sealing agents or agents that give compatibility to seals. 13. The use according to claim 6, in which the lubricating oil composition further comprises one or more additives selected from antioxidants, antiwear additives, additional detergent additives, dispersants, friction modifiers, viscosity index improvers, depressants, corrosion inhibitors, antifoam agents, and fast sealing agents or agents that give compatibility to seals. 14. The use of claim 8, in which the lubricating oil composition further comprises one or more additives selected from antioxidants, antiwear additives, additional detergents, dispersants, friction modifiers, viscosity index improvers, depressants, corrosion inhibitors, antifoam agents, and fast sealing agents or agents that give compatibility to seals.