RU2692794C2 - Lubricating composition - Google Patents

Abstract

FIELD: technological processes.SUBSTANCE: present invention relates to a lubricating composition for use in a crankcase of an internal combustion engine, comprising: (i) a base oil produced in Fischer-Tropsch synthesis in amount of 60 to 92 wt% with respect to the total weight of the lubricating composition; (ii) one or more molybdenum compounds selected from dithiocarbamates of molybdenum (MoDTC), dithiophosphates of molybdenum (MoDTP), molybdenum-amines, molybdenum alcoholates and amidealcohols of molybdenum and their mixtures, in an amount sufficient to provide from 100 to 1,000 pts.wt per mln of molybdenum; and (iii) from 0.2 to 5.0 wt%, based on the weight of the lubricating composition, one or more organic polymer additives which reduce friction, where one or more organic polymer additives which reduce friction have molecular weight in range of 1,000 to 30,000 units Da and is a product of interaction: a) a hydrophobic polymer subunit which contains a hydrophobic polymer selected from polyolefin, polyacrylic and polystyrene polymers; b) a hydrophilic polymer subunit which contains a hydrophilic polymer selected from polyethers, polyesters, polyamides; c) optionally at least one main chain group fragment which is capable of binding together polymer subunits; and d) optionally a chain termination group which is a fatty carboxylic acid.EFFECT: lubricating composition improves low friction and wear properties, as well as improved fuel economy characteristics.9 cl, 2 dwg, 4 tbl

Description

The technical field to which the invention relates.

The present invention relates to a lubricating oil composition, in particular to a lubricating oil composition, which is suitable for lubricating internal combustion engines and which has reduced friction and wear and improved fuel economy.

Increasing stringent restrictions on exhaust and fuel efficiency in automobiles impose increased demands on both engine manufacturers and lubricant formulations in order to provide effective solutions to improve fuel economy.

Prospective lubricants provide a flexible solution to increasing problems through the use of high-quality base oils and new additives.

Friction reducing additives (which are also known as friction modifiers) are important lubricant components to reduce fuel consumption, and such a variety of additives are already known in the art.

Friction modifiers can be conveniently divided into two categories, in other words, metal-containing friction modifiers and ashless (organic) friction modifiers.

Organic molybdenum compounds are among the most well-known metal-containing friction modifiers. Typical organo molybdenum compounds include molybdenum dithiocarbamates (MoDTC), molybdenum dithiophosphates (MoDTP), molybdenum amines, molybdenum alkoxides, and molybdenum alcohols. WO-A-98/26030, WO-A-99/31113, WO-A-99/47629 and WO-A-99/66013 describe trinuclear molybdenum compounds for use in lubricating oil compositions.

However, the tendency to use low-ash lubricating compositions leads to an increased desire to achieve low friction and improved fuel economy using ashless friction modifiers.

Ashless (organic) friction modifiers that have been used in the past usually include fatty acid esters of polyhydric alcohols, fatty acid amides, amines derived from fatty acids, and organic dithiocarbamate or dithiophosphate compounds.

However, modern strategies for oils to reduce friction and fuel economy are not sufficient to achieve even greater fuel economy goals formulated by original equipment manufacturers (OEMs). Although there is a problem of achieving similar levels of friction modification using only ashless friction modifiers, molybdenum friction modifiers usually exceed the ashless friction modifiers in borderline mode.

Although organo molybdenum compounds are effective in providing high levels of friction modification, limitations for these compounds are also known. For example, molybdenum-based friction modifiers can adversely affect shock seals and TEOST cleanliness tests.

With the increasing demands of fuel economy imposed on engines, there is a need to further reduce the coefficient of friction and fuel economy in internal combustion engines using small additives of molybdenum-based friction modifiers.

WO2011 / 107739 describes automotive motor oil and / or fuel containing base oil and an organic polymer friction reducing additive.

The authors of the present invention have unexpectedly found that a lubricating oil composition containing a combination of organo molybdenum compound and an organic polymer friction reducing additive improves friction and reduces wear and increases fuel economy, while at the same time it requires a reduced amount of additives of organo molybdenum compounds.

Summary of the Invention

Accordingly, the present invention provides a lubricating composition for use in an engine crankcase, comprising (i) a base oil; (ii) one or more organo-molybdenum compounds at a level that provides from 100 to 1000 mass. ppm molybdenum; and (iii) from 0.2 wt.% to 5 wt.%, by weight of the lubricating composition, one or more organic polymer additives that reduce friction, and one or more organic polymer additives that reduce friction, has a molecular weight in the range from 1000 to 30,000 units Dalton, and is the product of the interaction of reagents:

- a hydrophobic polymer subunit that contains a hydrophobic polymer selected from polyolefins, polyacryls and polystyrenes;

- hydrophilic polymer subunit, which contains a hydrophilic polymer selected from polyethers, polyesters, polyamides;

- optionally, at least one fragment of the main polymer chain capable of binding together polymeric subunits; and

- optional group of open circuit.

Brief Description of the Drawings

FIG. 1 shows the dependence of the friction coefficient, measured in the boundary and mixed modes, as a function of speed for the compositions shown in Table 2.

FIG. 2 shows the dependence of the friction coefficient, measured in the boundary and mixed modes, as a function of speed for the compositions shown in Table 4.

Detailed Description of the Invention

An essential component of the lubricating compositions of the present invention is one or more organic molybdenum compounds in an amount sufficient to provide from 100 to 1000 mass. ppm molybdenum, preferably in an amount sufficient to provide from 100 to 300 mass. ppm molybdenum.

The organo molybdenum compound for use in the invention is preferably selected from molybdenum dithiocarbamates (MoDTC), molybdenum dithiophosphates (MoDTP), molybdenum amines, molybdenum alcoholates, molybdenum amido alcohols, and mixtures thereof. A preferred organo molybdenum compound for use in the invention is molybdenum dithiocarbamate (MoDTC). In a preferred embodiment of the invention, the organo molybdenum compound contains a trinuclear molybdenum (referred to as “molybdenum trimer” in the invention).

Another significant component of the lubricating compositions of the present invention is one or more organic polymer additives that reduce friction, where one or more organic polymer additives that reduce friction has a molecular weight in the range from 1000 to 30,000 units. Dalton, and is a product of the interaction of reagents:

- a hydrophobic polymer subunit that contains a hydrophobic polymer selected from polyolefins, polyacryls and polystyrenes;

- hydrophilic polymer subunit, which contains a hydrophilic polymer selected from polyethers, polyesters, polyamides;

- optionally, at least one main chain fragment (one functional group of the main polymer chain) capable of binding together polymeric subunits; and

- optional, open circuit group.

The hydrophobic polymer subunit preferably contains a hydrophobic polymer, which is a polyolefin or poly-alpha olefin, more preferably a polyolefin.

The polyolefin is preferably prepared as a polymer of monolefin having from 2 to 6 carbon atoms, such as ethylene, propylene, butylene and isobutylene, more preferably isobutylene, moreover, said polymer contains a chain comprising from 15 to 500, preferably 50 to 200 carbon atoms.

The hydrophilic polymer subunit contains a hydrophilic polymer selected from polyethers, polyamides or polyesters. Examples of polyesters include polyethylene terephthalate, polylactide and polycaprolactone. Examples of polyethers include polyglycerol and polyalkylene glycol. In a particularly preferred embodiment, the hydrophilic polymer subunit contains a hydrophilic polymer that is a water soluble alkylene glycol polymer. The preferred hydrophilic polymer subunit contains a hydrophilic polymer which is polyethylene glycol (PEG), preferably PEG, having a molecular weight of from 300 to 5000 units. Dalton, more preferably from 400 to 1000 units. Dalton, particularly preferably from 400 to 800 units. Dalton. Alternatively, mixed poly (ethylene-propylene glycol) or mixed poly (ethylene-butylene glycol) can be used, provided that they fulfill the criterion of the desired solubility in water. Examples of hydrophilic polymer subunits for use in the present invention include PEG 400, PEG 600 and PEG 1000.

Other suitable hydrophilic polymeric subunits may contain hydrophilic polymers that are polyethers and polyamides derived from diols and diamines containing acidic groups, for example, carboxylic acid groups, sulfonyl groups (for example, sulfonyl styrene groups), amine groups (for example, tetraethylenepentamine ( TEPA) or polyethyleneimine (PEI)), or hydroxyl groups (for example, sugar-based mono- or copolymers).

The hydrophilic polymer subunit can be either linear or branched.

During the course of the reaction, some hydrophobic and hydrophilic polymeric subunits can bind together to form block copolymer units. Each or both of the hydrophobic and hydrophilic polymer subunits may contain functional groups that enable them to bind to another subunit. For example, a function having a diacid / anhydride group can be introduced into a hydrophobic polymer subunit by reacting with an unsaturated diacid or anhydride, for example, with maleic anhydride. Dicislot / anhydride can react esterification with hydroxyl-terminated hydrophilic polymer subunits, for example, with polyalkylene glycol. In an additional example, a function can be introduced into a hydrophobic polymer subunit by epoxidation reaction with a peracid, for example, perbenzoic or peracetic acid. Then, the epoxide can interact with polymer subunits with hydroxyl and / or acidic hydrophilic end groups. In an additional example, a functional group can be introduced into a hydrophilic polymeric subunit that has a hydroxyl group by esterifying an unsaturated monocarboxylic acid, such as vinyl acids, especially acrylic or methacrylic acid. Then the hydrophilic polymer subunit with a functional group can interact with the polyolefin hydrophobic polymer subunit by free radical copolymerization.

A particularly preferred hydrophobic polymer subunit contains a polyisobutylene polymer that has been maleised to form a polyisobutylene succinic anhydride (PIBSA) having a molecular weight in the range from 300 to 5000 units. Dalton, preferably from 500 to 1500 units. Dalton, especially from 800 to 1200 units. Dalton. Polyisobutylene-succinic anhydrides are commercially available compounds that are obtained by an addition reaction between poly (isobutylene), having a terminal unsaturated group, and maleic anhydride.

Such block copolymer units, if they are present, can be directly linked to each other and / or they can be linked together using at least one fragment (one functional group) of the main chain. Preferably, the blocks are linked together with at least one fragment of the main chain. The choice of the main chain fragment that is able to bind the blocks of a copolymer together is determined by whether the connecting links are between two hydrophobic polymer subunits, between two hydrophilic polymer subunits or between a hydrophobic polymer subblock and a hydrophilic polymer subblock. Typically, polyols and polycarboxylic acids form suitable backbone moieties. This polyol may be a diol, triol, tetraol, and / or related dimers or trimers or polymers of such long chain compounds. Examples of suitable polyols include glycerin, neopentenyl glycol, trimethylol ethane, trimethylol propane, trimethylolbutane, pentaerythritol, dipentaerythritol, tripentaerythritol and sorbitol. In a preferred embodiment, the polyol is glycerol. It is advisable that at least one fragment of the main chain be produced from polycarboxylic acid, for example di- or tricarboxylic acids. Dicarboxylic acids are preferred polycarboxylic acids, although branched chain dicarboxylic acids may also be suitable. Particularly suitable are linear chain dicarboxylic acids having a length of between 2 and 10 carbon atoms, for example oxalic, malonic, succinic, glutaric, adipic, pimelic, octanecarboxylic, azelaic or sebacic acid. Unsaturated dicarboxylic acids, such as maleic acid, may also be suitable. A particularly preferred fragment of the polycarboxylic acid backbone for linking the units is adipic acid. Alternative backbone binding moieties are low molecular weight alkenylsuccinic anhydrides (AAA), such as C ₁₈ -AHAA.

In any of the organic polymer additives that reduce friction, different or identical fragments of the main chain can be used to bind such block copolymer units together. When present, the number of units of the block copolymer in an organic polymer additive that reduces friction is usually in the range from 1 to 20 units, preferably from 1 to 15, more preferably from 1 to 10, and especially from 1 to 7 units.

When the reaction product ends with a reactive group (such as, for example, —OH in PEG), it may in some cases be desirable or useful to introduce a terminating group that terminates the chain of the reaction product. For example, it is especially easy to attach a carboxylic acid to an unprotected hydroxyl group in PEG to form an ester bond. Therefore, any fatty carboxylic acid may be suitable. Suitable fatty acids include C ₁₂ -C ₂₂ saturated linear, branched saturated, linear unsaturated and branched unsaturated acids, including (but not limited to) lauric acid, erucic acid, isostearic acid, palmitic acid, oleic acid and linoleic acid, preferably palmitic acid, oleic acid and linoleic acid. A particularly preferred fatty acid for combination with a surfactant is tall oil fatty acid (TOFA), a tall oil derivative that is mainly oleic acid.

The organic polymer friction reducing additive used in the invention has a molecular weight of from 1000 to 30,000 units. Dalton, preferably from 1,500 to 25,000, more preferably from 2,000 to 20,000 units. Dalton. Typically, a composition containing an organic polymer friction reducing additive may include a series of polymer chains of various lengths, so that a specific composition yields a range of molecular weights. In this case, it is desirable that a significant part of the molecules of the organic polymer additive, which reduces friction, are within the above size ranges.

In the invention, the organic polymer friction reducing additive has a desired acid number of less than 20, preferably less than 15.

In one embodiment of the invention, the organic polymer friction reducing additive is an interaction product:

- a hydrophobic polymer subunit that contains a hydrophobic polymer selected from polyolefins, polyacryls and polystyrenes;

- hydrophilic polymer subunit, which contains a hydrophilic polymer selected from polyethers, polyesters, polyamides; and

d) chain breaking group.

For this embodiment, the preferred molecular weight range is from 1000 to 3000 units. Dalton and the desired acid number is less than 15.

In a separate embodiment of the invention, an organic polymer additive that reduces friction is a product of the interaction:

- a hydrophobic polymer subunit that contains a hydrophobic polymer selected from polyolefins, polyacryls and polystyrenes;

- hydrophilic polymer subunit, which contains a hydrophilic polymer selected from polyethers, polyesters, polyamides; and

- at least one fragment of the main polymer chain capable of binding together polymeric subunits.

For such an embodiment, the preferred molecular weight range is from 3,000 to 25,000 units. Dalton, more preferably from 5,000 to 20,000 units. Dalton. The desired acid number is preferably less than 10, more preferably less than 7.

In another embodiment, the organic polymer additive that reduces friction is the product of the interaction:

- a hydrophobic polymer subunit that contains a hydrophobic polymer selected from polyolefins, polyacryls and polystyrenes;

- hydrophilic polymer subunit, which contains a hydrophilic polymer selected from polyethers, polyesters, polyamides;

- at least one fragment of the main polymer chain capable of binding together polymeric subunits; and

- group breaking the chain.

For such an embodiment, the preferred molecular weight range is from 2,000 to 10,000 units. Dalton, more preferably from 2000 to 5000 units. Dalton. The desired acid number is preferably less than 15, more preferably less than 10.

The components of reactions a), b) and c), if present, and d), if present, can be mixed in one process step or they can be mixed together in several steps of the process.

The friction reducing organic polymer additive described above is commercially available from Croda, under the trade names Perfad 3050 and Perfad 3006.

Organic polymer additive that reduces friction, is present in an amount of from 0.2 wt.% To 5.0 wt.%, Preferably in an amount of from 0.3 wt.% To 3.0 wt.%, More preferably 0.2 wt. % to 1.5 wt.%, by weight of the lubricating composition.

The total amount of base oil introduced into the lubricating oil composition of the present invention is preferably present in a quantitative range from 60 to 92 wt.%, More preferably, in a quantitative range from 75 to 90 wt.%, And most preferably, in a quantitative range from 75 to 88 wt.%, Relative to the total weight of the lubricating composition.

There are no particular limitations with respect to the base oil used in the present invention, and various traditionally known mineral oils and synthetic oils can usually be used.

The base oil used in the present invention may typically contain mixtures of one or more mineral oils and / or one or more synthetic oils.

Mineral oils include liquid petroleum oils and solvent-treated or acid-treated mineral lubricating oils of paraffinic, naphthenic, or mixed paraffinic / naphthenic type, which can be further refined in final hydrotreating and dewaxing processes.

Naphthenic base oils have a low viscosity index (VI) (usually 40–80) and a low pour point (pour point). Such base oils are made from raw materials enriched in naphthenic hydrocarbons, with a low wax content, and are used mainly in lubricants for which color and its stability matter, and IV and oxidative stability are of secondary importance.

Paraffin base oils have a higher IV (usually> 95) and a high pour point. These base oils are made from raw materials enriched in paraffin hydrocarbons, and are used in lubricants for which IV and oxidative stability are important.

Base oils produced in Fischer-Tropsch synthesis can easily be used as base oils for the lubricating oil composition of the present invention, for example, base oils produced in Fischer-Tropsch synthesis and described 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 create molecules from simpler substances or to obtain molecules with a modified structure that have the required specific properties.

Synthetic oils include hydrocarbon oils, such as olefinic oligomers (PAO), dibasic esters, polyol esters, and a dewaxed waxy raffinate. Synthetic hydrocarbon base oils sold by the Royal Dutch / Shell group of companies with the designation "XHVI" (trade mark) can be conveniently used.

Preferably, the base oil contains mineral oils and / or synthetic oils that contain more than 80% by weight of saturated compounds, preferably more than 90% by weight, as measured by ASTM D2007.

Additionally, it is preferable that the base oil contains less than 1.0 wt.%, Preferably less than 0.1 wt.% Sulfur, based on elemental sulfur, as measured by ASTM D2622, ASTM D4294, ASTM D4927 or ASTM D3120.

Preferably, the viscosity index of the base oil is greater than 80, more preferably greater than 120, as measured by ASTM D2270.

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

The total amount of phosphorus in the lubricating oil composition of the present invention is preferably in the range from 0.04 to 0.12 wt.%, More preferably in the range from 0.04 to 0.09 wt.% And most preferably in the range from 0.045 to 0, 08 wt.%, Calculated on the total weight of the lubricating composition.

Preferably, the lubricating oil composition of the present invention has a sulfate ash content of not more than 2.0% by weight, more preferably not more than 1.0% by weight, and most preferably not more than 0.8% by weight, based on the total weight of the lubricating oil composition.

Preferably the composition of the lubricating oil of the present invention has a sulfur content of not more than 1.2 wt.%, More preferably not more than 0.8 wt.% And most preferably not more than 0.2 wt.%, Calculated on the total the weight of the lubricating oil composition.

In addition, the lubricating oil composition of the present invention may contain additional additives, such as antioxidants, anti-wear additives, detergents, dispersants, additional friction modifiers, additives that improve the viscosity index, temperature drop-point loss additives, corrosion inhibitors, anti-foam additives and seal fixation additives. or seal compatibility.

A particularly preferred additional additive for use in the invention in combination with an organo-molybdenum compound and an organic polymer friction reducing additive as described above is a hydroxyalkylamine friction modifier, such as commercially available from Adeka under the trade names Adeka FM926. If a hydroxyalkylamine friction modifier is present, its amount is from 0.2 wt.% To 3.0 wt.%, More preferably from 0.3 wt.% To 1.0 wt.%, Based on the weight of the lubricating composition.

Antioxidants that can be conveniently used include those selected from the group of amine antioxidants and / or phenolic antioxidants.

In a preferred embodiment, said antioxidants are present in an amount in the range from 0.1 to 5.0% by weight, more preferably in an amount in the range from 0.3 to 3.0% by weight, and most preferably in an amount in the range from 0.5 to 1.5 wt.%, Calculated on the total weight of the lubricating composition.

Examples of amine antioxidants that can be conveniently used include alkylated diphenylamines, phenyl-α-naphthylamines, phenyl-β-naphthylamines, alkylated α-naphthylamines.

Preferred amine antioxidants include dialkyldiphenylamines, such as para, para'-dioctyldiphenylamine (p-p'-dioctyldiphenylamine), p, p'-di-α-methylbenzyl diphenylamine and N-p-butylphenyl-N-p'-octylphenylamine, monoalkyl, n-but-alkyl, N-p'-octylphenylamine, monoalkylphenylamine and as mono-tert-butyldiphenylamine and mono-octyldiphenylamine, 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, aryl-naphtylamines, such as phenyl-1-naphthylamine, phenyl-2-naphty amine, N-hexylphenyl-2-naphthylamine and N-octylphenyl-2-naphtylamine, phenylenediamine, such as N, N'-diisopropyl-p-phenylenediamine and N, N'-diphenyl-p-phenylenediamine, and phenothiazine, such as phenothiazine , and 3,7-dioctylphenothiazine.

Preferred amine antioxidants include those available under the following trade names: “Sonoflex OD-3” (used by Seiko Kagaku Co.), “Irganox L-57” (used by Ciba Specialty Chemicals Co.) and phenothiazine, (used by Hodogaya Kagaku Co.).

Examples of phenolic antioxidants that can be conveniently used include C ₇ -C ₉ branched alkyl esters of 3,5-bis (1,1-dimethylethyl) -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-butylhydroquinone, 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, such as 2,6-di-tre -butyl-4-methoxyphenol and 2,6-di-tert-butyl-4-ethoxyphenol, 3,5-di-tert-butyl-4-hydroxybenzylmercaptooctylacetate, 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-para-cresol, 2,2'-methylenebis (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'-butylidene-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), hexamethylenegly col-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-t-butyl-4-hydroxyphenyl) propionate], 3,9-bis {1,1-dimethyl-2- [3- (3-t-butyl- 4-hydroxy-5-methylphenyl) propionyloxy] ethyl} 2,4,8,10-tetraoxospiro [5,5] -undecane, 4,4'-thiobis (3-methyl-6-tert-butylphenol) and 2,2 '-thiobis (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-hydrox benzyl) 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 para-tert-butylphenol and formaldehyde condensates and p-tert-butylphenol condensates with acetaldehyde.

Preferred phenolic antioxidants include those available under the following trade names: “Irganox L-135” (isp. Ciba Specialty Chemicals Co.), “Yoshinox SS” (isp. Yoshitomi Seiyaku Co.), “Antage W-400” (isp Kawaguchi Kagaku Co.), “Antage W-500” (used by Kawaguchi Kagaku Co.), “Antage W-300” (used by Kawaguchi Kagaku Co.), “Irganox L109” (used by Ciba Specialty Chemicals Co.) , “Tominox 917” (used by Yoshitomi Seiyaku Co.), “Irganox L115” (used by Ciba Specialty Chemicals Co.), “Sumilizer GA80” (used by Sumitomo Kagaku), “Antage RC” (used by Kawaguchi Kagaku Co. ), “Irganox L101” (isp. Ciba Specialty Chemicals Co.), “Yoshinox 930” (isp. Yoshitomi Seiyaku Co.).

The lubricating oil compositions of the present invention may contain mixtures of one or more phenolic antioxidants with one or more amine antioxidants.

In a preferred embodiment, the lubricating oil compositions may contain a single zinc dithiophosphate or a combination of two or more zinc dithiophosphates as anti-wear additives, each zinc dithiophosphate selected from dialkyl, diaryl or alkylaryl zinc dithiophosphates.

Zinc dithiophosphate is a well-known additive in the art and can be conveniently represented by the general formula II;

in which R2 - R5 may be the same or different and each is 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, a substituted alkyl group, wherein said alkyl substituent contains from 1 to 20 carbon atoms, preferably from 3 to 18 carbon atoms.

Dithiophosphate zinc compounds, in which all R2 - R5 groups are different, can be used alone or in a mixture with dithiophosphate zinc compounds, in which all R ² - R ⁵ groups are the same.

Preferably, each zinc dithiophosphate used in the present invention is zinc dialkyldithiophosphate.

Examples of suitable zinc dithiophosphates that are commercially available include those available from Lubrizol Corporation under the trade designations “Lz 1097” and “Lz 1395”, those available from Chevron Oronite under the trade designations “OLOA 267” and “OLOA 269R ”, those available from Afton Chemical under the trade designation“ HITEC 7197 ”; zinc dithiophosphates, such as those available from Lubrizol Corporation under the trade designations “Lz 677A”, “Lz 1095” and “Lz 1371”, those available from the company Chevron Oronite under the trade designation “OLOA 262” and those that are available from Afton Chemical under the trade designation “HITEC 7169”; and such zinc dithiophosphates which are available from Lubrizol Corporation under the trade designations “Lz 1370” and “Lz 1373” and those that are available from Chevron Oronite under the trade designation “OLOA 260”.

The lubricating oil compositions according to the present invention may mainly contain zinc dithiophosphate in the range of 0.4 to 1.2% by weight, based on the total weight of the lubricating composition.

Additional or alternative anti-wear additives may be conveniently used in the composition of the present invention.

Typical detergents that can be used in the lubricating oil of the present invention include one or more salicylate and / or phenolate and / or sulphonate detergents.

However, since organometallic and inorganic base salts, which are used as detergent additives, can contribute to the sulfate ash content of a lubricating oil composition, in a preferred embodiment of the present invention, the amount of such additives is minimized.

Salicylate detergents can be used to maintain a low sulfur content.

Thus, in one embodiment, the lubricating oil composition of the present invention may contain one or more salicylate detergents.

In order to maintain the total sulphate ash content for the lubricating oil composition of the present invention in an amount preferably not more than 2.0 wt.%, More preferably in an amount not more than 1.0 wt.% And most preferably in an amount not more than 0.8 wt.%, calculated on the total weight of the lubricating composition, these detergents are preferably used in amounts ranging from 0.05 to 20.0 wt.%, more preferably from 1.0 to 10.0 wt. .% and most preferably in the range from 2.0 to 5.0 wt.%, in the calculation Use on the total weight of the lubricating oil composition.

Moreover, it is preferable that said detergents independently have an RAD value (total base number) in the range from 10 to 500 mg KOH / g, more preferably in the range from 30 to 350 mg KOH / g, and most preferably in the range from 50 to 300 mg KOH / g, which is measured according to ISO 3771.

Additionally, the lubricating oil composition of the present invention may contain an ashless dispersant additive, which is preferably mixed in an amount in the range from 5 to 15 wt.%, Calculated on the total weight of the lubricating composition.

Examples of ashless dispersant additives that can be used include polyalkenylsuccinimides and polyalkenylsucate esters described in Japanese Patent Nos. 13,67796, 1667140, 1302811 and 1743435. Preferred dispersing additives include boron-containing succinimides.

Examples of viscosity index improvers that can be conveniently used in the lubricating oil composition of the present invention include styrene-butadiene copolymers, styrene-isoprene star-shaped copolymers, and polymethyl methacrylate copolymers and ethylene-propylene copolymers. These viscosity index improvers can be conveniently used in an amount in the range of from 1 to 20% by weight, based on the total weight of the lubricating composition.

Polymethylmethacrylates can be conveniently used in the lubricating oil compositions of the present invention as effective additives that reduce the pour point.

In addition, compounds such as alkenylsuccinic acids or its ester derivatives, benzotriazole-based compounds, and thiodiazole-based compounds can be conveniently used in the lubricating oil compositions of the present invention as corrosion inhibitors.

Compounds such as polysiloxanes, dimethyl polycyclohexane and polyacrylates can be conveniently used in the lubricating oil compositions of the present invention as antifoam additives.

Compounds that can be conveniently used in the lubricating oil composition of the present invention as an additive for seal fixation or seal compatibility include, for example, industrially available aromatic acid esters.

Lubricating compositions of the present invention can be conveniently prepared using conventional formulation techniques, by mixing the base oil with an organo-molybdenum compound and a polymeric friction reducing agent, together with one or more other optional additives at 60 ° C.

In another embodiment of the present invention, a method for lubricating an internal combustion engine has been developed, which includes the use of a lubricating oil composition as described above in the invention.

The present invention further provides the use of a lubricating composition as described above to reduce friction.

The present invention further provides the use of a lubricating composition as described above to reduce wear.

The present invention further provides the use of a lubricating composition as described above to improve fuel economy.

The present invention is described below with reference to the following Examples, which are not intended to limit the scope of the present invention in any way.

Examples

The formulation of the lubricating composition is made using traditional methods of mixing lubricants (“Base oil A”), having the composition shown below in table 1.

The number of components is given in wt.%, Calculated on the total weight of the composition.

Table 1. Base Oil Composition A

Component Mass% GTL 4 ¹ 79.50 Additive Package ² 13.30 Viscoplex 3-201 ³ 6.90 PPD ⁴ 0.30

1. A base oil based on Fischer-Tropsch synthesis, having a kinematic viscosity at 100 ° C (ASTM D445) of approximately 4 cSt, which can be conveniently obtained by the method described in WO 02/070631.

2. A complete package of SAPS additives containing polyisobutylene-succinimide dispersant additive, zinc alkyl dithiophosphate, alkyl salicylate detergent additive with excess calcium, boron dispersant additive and diphenylamine antioxidant.

3. Viscosity modifier commercially available from Evonik.

4. Polyalkylmethacrylate additive that lowers the pour point.

Base oil A has a HF 100 (as measured by ASTM D445) equal to 8.02 mm ² / s, KW 40 (as measured by ASTM D445) 35.18 mm ² / s, a crankshaft cranking engine simulator (CCS) at -35 ° C (as measured by ASTM D5293) 4330 mPa.s, and the high-temperature oil viscosity setting (HTHS, as measured by ASTM D4741) is 2.74 mPa.s.

Various friction modifiers are added to the base oil A in the amounts shown below in Table 2 to obtain a range of test oils. Friction modifiers added to base oil A are organo-molybdenum compounds (molybdenum dithiocarbamate (MoDTC) containing a trinuclear molybdenum complex, named in table 2 and figure 1 as “Molybdenum Trimer”), a polymeric friction-reducing additive (Perfad 3006 available from from Croda) and glycerol monooleate (MTF), a well-known and conventional friction modifier.

Measurement of friction is carried out for the compositions listed in table 2, using a mini-friction unit (MTM), manufactured by PCS Instruments.

Tests at MTM were described by RITaylor, E. Nagatomi, NR Horswill, DM James in “A screener test” presented at the International Colloquium on Tribology (13 ^th International Colloquium on Tribology), in January 2002 year

Friction coefficients are measured using a mini-friction unit using the ‘ball-on-disk’ configuration.

The ball is a polished steel ball bearing with a diameter of 19.05 mm. The disk sample is mounted concentrically on a motor driven shaft. The ball acts on the ball relative to the disk in order to create a contact point area with a minimum contribution of rotation and skew. At the point of contact, the ratio of slip to rolling is maintained at 100% by adjusting the peripheral speed of the ball and the disk.

The tests are carried out at a pressure of 1.25 hPa (load 71 N) at a temperature of 115 ° C and at a variable speed from 2600 mm / s up to 5 mm / s, as shown in FIG. 1 and 2.

Each oil is tested using a new ball and a new disc, for a total of 20 test surveys (scans), and friction results were selected from the last three scans.

The friction coefficients were measured for the respective test oils (which are listed in Table 2), and the results are presented below in Table 2. In Table 2, the friction boundary coefficient is an average value at low speeds from 0.05 m / s to 0.05 m / c, and the mixed friction coefficient is an average value at elevated speeds from 1.0 m / s to 2.6 m / s.

Table 2. Results

Test oils Friction coefficient Boundary Mixed Base oil A 0.107 0.074 99.25 wt.% Base oil A + 0.75 wt.% Perfad 3006 0.118 0.067 96.25 wt.% Base oil A + 3% Molybdenum trimer + 0.75% glycerol monooleate 0.112 0.035 99 wt.% Base oil A + 0.25% Molybdenum trimer + 0.75% Perfad 3006 0.055 0.044

FIG. 1 shows the dependence of the friction coefficient, measured in the boundary and mixed modes, on the speed for the compositions given in Table 2.

The additional lubricating composition was formulated using traditional methods of mixing lubricants (“Base oil B”) and has the composition shown in Table 3 below.

Table 3. The composition of the base oil B

Component Mass% GTL4 ¹ 80.70 SV277 ² 7.20 Additive package ³ 12.1

1. Base oil produced in Fischer-Tropsch synthesis, having a kinematic viscosity of approximately 4 cSt at 100 ° C (ASTM D445), which can be conveniently obtained by the method described in WO 02/070631.

2. Hydrogenated styrene-diene copolymer.

3. An additive package containing polyisobutylene-succinimide dispersant, zinc alkyldithiophosphate, alkylphenolate with excess calcium and sulfonate detergents, and a phenolic antioxidant.

Base oil B has KB100 (as measured by ASTM D445) equal to 8.93 mm ² / s, KB40 (as measured by ASTM D445) 45.20 mm ² / s, IV 183, oil viscosity parameter HTHS at 150 ° C (according to measurements according to ASTM D4741) 2.52 cP, HTHS at 100 ° C (according to measurements according to ASTM D4741) 5.55 cP.

Add various friction modifiers to Base Oil B in the amounts indicated below in Table 4 to obtain a range of test oils. The friction modifiers added to Base Oil B are organo-molybdenum compounds (molybdenum dithiocarbamate (named in Table 4 and in Fig. 2 as 'Molybdenum Trimer')), a polymeric friction reducing agent (Perfad 3050, commercially available from Croda) and Adeka FM926 (hydroxyalkylamine friction modifier, commercially available from Adeka).

 The values of the friction coefficients for the respective test oils (which are listed in Table 4) were measured using the MTM test method described above, and the detailed results are shown below in Table 4. In Table 4, the friction boundary coefficient is an average value at low speeds from 0.05 m / s to 0.05 m / s, and the mixed friction coefficient is an average value at elevated speeds from 1.0 m / s to 2.6 m / s.

Table 4. Results

Test Oil Friction coefficient Boundary Mixed Base oil B 0.141 0.076 99.5 wt.% Base oil B + 0.5 wt.% Perfad 3050 0.092 0.039 99.5 wt.% Base oil B + 0.5 wt.% Adeka FM926 0.094 0.034 99.45 wt.% Base oil B + 0.55 wt.% Molybdenum trimer 0.048 0.040  wt.% Base oil B + 1% Perfad 3050 + 0.1 wt.% Adeka FM926 + 0.36 wt.% Molybdenum trimer 0.048 0.033

FIG. 2 shows the dependence of the friction coefficient, measured in the boundary and mixed modes on the speed for the compositions given in Table 4.

Discussion

Four main lubrication modes are distinguished: (1) Hydrodynamic, in which the surfaces are completely separated by a fluid film, (2) elastic, hydrodynamic, in which the surfaces are separated by a very thin fluid film, (3) mixed, in which the surfaces are partially separated due to some contact of the surface protrusions (4) boundary, in which the surfaces are mainly in contact, even if a fluid film is present. In the mixed and boundary modes, chemical anti-wear additives and / or friction modifiers and the like are used to reduce wear and friction.

It is usually expected that molybdenum-containing friction modifiers work well in reducing boundary friction, and it is assumed that organic friction modifiers are more effective under mixed conditions.

As can be seen in Table 2, the addition of 0.75% of a single polymer organic friction modifier to Base Oil A reduces friction in mixed mode, but it turned out that the boundary friction increases.

When 170 ppm was added to Base Oil A Mo (3 wt.% MoDTC) with 0.75% of the conventional organic friction modifier, MOG, the authors observed a slight decrease in boundary friction and a significant decrease in mixed friction.

When only 140 ppm was added Mo (0.25 wt.% MoDTC) with 0.75% polymer organic modifier, unexpectedly, the authors observed a sharp decrease in boundary friction and an additional decrease in mixed friction. It turned out that there is a true synergistic effect that could not have been foreseen from the other results in Table 2.

It turned out that the polymeric organic friction modifier itself increases the boundary friction, but provides very low friction boundary in combination with the molybdenum-containing friction modifier, the content of which is much less than in the case of the combination of the molybdenum-containing friction modifier with the traditional organic friction modifier, is.

The addition of 0.5% other organic polymer friction modifier (Perfad 3050) to Base Oil B significantly reduces boundary and mixed friction.

It turned out that the hydroxyalkylamine friction modifier (Adeka FM926) is more effective in mixed mode, but slightly less effective in reducing boundary friction.

When 300 ppm of base oil B is added Mo (0.55 wt.% Dithiocarbonate of molybdenum containing trinuclear molybdenum (indicated in Tables 2 and 4, and in Fig. 1 and 2, as the 'Molybdenum Trimer')), the authors observed a very large decrease in boundary as well as mixed friction, although it turned out that the mixed friction is minimal above the friction, which is achieved with the help of organic friction modifiers.

When a 200 ppm combination was added to the Base Oil B Mo (0.36 wt.% Molybdenum trimer) in combination with 1% Perfad 3050 and 0.1% hydroxyalkylamine (Adeka FM925) friction modifier, the authors observed very low friction in the boundary as well as in the mixed mode. Unexpectedly, the boundary friction is reduced using only 200 ppm. Mo in this combination, when compared with friction measured using Mo alone (300 ppm).

Claims (16)

1. Lubricating composition for use in the crankcase of an internal combustion engine, containing: (i) a base oil produced in Fischer-Tropsch synthesis, in an amount of from 60 to 92 wt.% calculated on the total weight of the lubricating composition; (ii) one or more organic molybdenum compounds selected from molybdenum dithiocarbamates (MoDTC), molybdenum dithiophosphates (MoDTP), molybdenum amines, molybdenum alcoholates and molybdenum amido alcohols and their mixtures in an amount sufficient to provide from 100 to 1000 mass. ppm molybdenum; and (iii) from 0.2 to 5.0 wt.%, based on the weight of the lubricating composition, of one or more organic polymer additives that reduce friction, where one or more organic polymer additives that reduce friction has a molecular weight in the range of 1000 up to 30,000 units And it is a product of interaction: a) a hydrophobic polymer subunit that contains a hydrophobic polymer selected from polyolefins, polyacrylics and polystyrenes; b) a hydrophilic polymer subunit that contains a hydrophilic polymer, which is a complex polyester; c) optionally at least one fragment of the main chain, which is capable of binding together polymeric subunits; and d) optionally, a chain termination group, which is a fatty carboxylic acid. 2. A lubricating composition according to claim 1, in which the hydrophobic polymer subunit contains a hydrophobic polymer, which is a polyolefin. 3. A lubricating composition according to claim 1 or 2, in which the hydrophobic polymer subunit contains a polyisobutylene polymer, which has been subjected to maleation to form a polyisobutylene-succinic anhydride having a molecular weight in the range from 300 to 5000 units. Yes. 4. Lubricating composition according to any one of paragraphs. 1-3, in which the hydrophilic polymer subunit contains a hydrophilic polymer, which is polyethylene glycol. 5. Lubricating composition according to any one of paragraphs. 1-4, in which the fragment of the main chain is selected from a polyol, polycarboxylic acid and mixtures thereof. 6. Lubricating composition according to any one of paragraphs. 1-5, in which the product of the interaction contains several units of the block copolymer formed by binding together during the reaction of several hydrophobic and hydrophilic polymer subunits. 7. Lubricating composition according to any one of paragraphs. 1-6, in which one or more organo-molybdenum compounds is molybdenum dithiocarbamate (MoDTC). 8. Lubricating composition according to any one of paragraphs. 1-7, additionally containing hydroxyalkylamine. 9. The use of a lubricating composition according to any one of paragraphs. 1-8 in the crankcase of an internal combustion engine to reduce friction.

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