EP1771532A1

EP1771532A1 - Use of graft polymers

Info

Publication number: EP1771532A1
Application number: EP05762298A
Authority: EP
Inventors: Markus Scherer; Klaus Hedrich; Alexander Dardin; Michael Müller; Torsten Stöhr; Boris Eisenberg
Original assignee: RohMax Additives GmbH
Current assignee: Evonik Oil Additives GmbH
Priority date: 2004-07-16
Filing date: 2005-06-23
Publication date: 2007-04-11
Also published as: MX2007000629A; KR101397837B1; JP2013129847A; DE102004034618A1; BRPI0513435A; JP5419351B2; WO2006007934A1; KR101397872B1; JP2008506794A; CN101076578A; KR20070042970A; KR20130114251A; US9080124B2; US20070213237A1; CN101076578B; CA2571714A1; CA2571714C

Abstract

The invention relates to the use of graft polymers obtained by polymerization in two stages. In a first stage, at least one graft basis is produced by radically polymerizing a monomer composition A) containing 0 to 40 percent by weight of one or several ethylenically unsaturated ester compounds of formula (I), wherein R represents hydrogen or methyl, R1 represents a linear or branched alkyl radical comprising 1 to 5 carbon atoms, R2 and R3 independently represent hydrogen or a group of formula -COOR', wherein R' represents hydrogen or an alkyl group comprising 1 to 5 carbon atoms, 60 to 100 percent by weight of one or several ethylenically unsaturated ester compounds of formula (II), wherein R represents hydrogen or methyl, R4 represents a linear or branched alkyl radical comprising 6 to 40 carbon atoms, R5 and R6 independently represent hydrogen or a group of formula -COOR', wherein R' represents hydrogen or an alkyl group comprising 6 to 40 carbon atoms, and 0 to 40 percent by weight of comonomers, the percentages being relative to the weight of monomer composition A). In a second stage, a monomer composition B) containing 20 to 100 percent by weight of at least one monomer that comprises at least one nitrogen-containing group is grafted onto the graft basis in order to reduce wear in lubricant oil compositions. Said graft polymer comprises a maximum of 200 ppm of sulfur while the weight ratio between monomer composition A) and monomer composition B) ranges between 99.7:0.3 and 80:20.

Description

Use of graft copolymers

The present invention relates to the use of graft copolymers.

According to the current state of the art, crank mechanism, piston group, cylinder bore and the valve control of an internal combustion engine are lubricated with an engine oil. Here, the engine oil, which collects in the oil sump of the engine is conveyed by means of feed pump via an oil filter to the individual lubrication points (pressure circulation lubrication, in conjunction with spray and oil mist lubrication).

The engine oil in this system has the functions: transmission of forces, reduction of friction, reduction of wear, cooling of components and gas sealing of the piston.

The oil is supplied to the bearing points under pressure (crankshaft, connecting rod, and camshaft bearings). The sliding points of the valve train, the piston group, gears and chains are supplied with splash oil, centrifugal oil or oil mist.

At the individual lubrication points vary in operation to be transmitted forces, contact geometry, sliding speed and temperature in a wide range.

Increasing the power density of the engines (kW / displacement and torque / displacement) leads to higher component temperatures and surface pressures of the sliding points.

To ensure engine oil performance under these operating conditions, engine manufacturers require proof of performance of an engine oil in the form of test results of standardized test procedures and engine tests (e.g., API Classification in USA or ACEA Test Sequences in Europe). In addition, self-defined test methods are used by individual manufacturers before an engine oil is approved for use.

The test in commercially available car and truck engines ensures that engine oil-related signs of wear and tear are recognized before the approval is granted. Of the above-mentioned lubricating oil properties, the wear protection of the engine oil is of particular importance. The list of requirements of the ACEA Test Sequences 2002 as an example shows that in each category (A for petrol engines, B for passenger car diesel engines and E for truck engines) with a separate engine test the proof of sufficient wear protection for the valve train is to be led.

As mentioned above, the approval procedures of individual manufacturers include additional further engine tests with their own engines and test programs for assessing the wear behavior.

Wear-reducing additives are known in the art. However, such additives are expensive and in some cases have compatibility problems. Such additives are mostly phosphorus and / or sulfur-containing. In this context, it should be considered that there is a desire within the lubricant industry to reduce the input of phosphorus and sulfur into modern lubricating oil formulations. This has both technical (avoidance of exhaust gas catalyst poisoning) as well as environmental reasons. The search for phosphorus- and sulfur-free lubricant additives has thus recently generated intensive research activities by many additive manufacturers.

The article "The contribution of new dispersant mixed polymers to the economy of engine oils" (Pennewiss, Auschra) published in Lubrication Science (1996, 8, 179-197) discusses the beneficial effects of additives composed of ethylene-propylene copolymers as well as methacrylates , which partially contain ethoxylated side chains, effects of this chemistry on dispersing effect in motor oils are shown as well as advantages in the wear behavior are described The systems used are to be manufactured in relatively complex dispersing methods.

NL 6505344 (20.10.1966) by Shell describes a synergistic mode of action of oil-soluble polymers with typical wear-reducing additive types, such as dispersed Ca salts or hydroxides. Shell's US 3,153,640 (Oct. 20, 1964) comprises copolymers consisting of two portions of methacrylate monomers and one NVP fraction. These are not graft copolymers. The beneficial effect on wear in lubrication applications is mentioned. However, the improvement is relatively limited. This is especially true when taking into account the high anteisl on costly comonomers, such as N-vinylpyrrolidone (NVP).

JP 05271331 (Nippon OiI) describes VI and wear-improving polymers prepared from copolymers of α-olefins and maleic acid which are subsequently functionalized. In the abstract rubbing and wear results obtained in the Falex test (block-on-ring) are given.

E. H. Okrent describes in the ASLE Transactions (1961, 4, 97-108) that polyisobutylenes or PAMA polymers used as VI improvers have an influence on the wear behavior in the engine. Conclusions on the chemistry used and the specific composition of the polymers are not made. A wear-reducing effect is justified only with viscoelastic effects of polymer-containing oils. For example, no differences in influence on wear between PAMA and PIB-containing oils were found.

Literature publications by Neudörfl and Schödel (Schmierungstechnik 1976, 7, 240-243, SAE Paper 760269, SAE Paper 700054, The Applied Macromolecular Chemistry 1970, 2, 175-188) mainly emphasize the influence of polymer concentration on engine wear. Reference is made to the above-mentioned article by EH Okrent and, in analogy to Okrent, a wear-improving effect is not associated with the chemistry of the polymer. Generally, it is concluded that lower molecular weight viscosity index improvers provide improved wear results. A publication also discusses wear as a function of HT / HS properties. Like Neudörfl and Schödel, K. Yoshida (Tribology Transactions 1990, 33, 229-237) attributes effects of polymers on wear behavior to viscometric aspects only. Beneficial effects are explained by the preferred tendency for elasto-hydrodynamic film formation.

EP 164807 (18.12.1985) by Agip describes a multifunctional VI improver with dispersing, deterging and low-temperature action. In addition, and not at the heart of this invention, a wear-reducing effect is mentioned, which is rather attributed to advantages in corrosion behavior, ie an indirect influence on wear. The composition comprises the VI improvers comprising specific sulfur-containing moieties. The wear-reducing effect of sulfur compounds is known. However, the use of sulfur-containing compounds is associated with disadvantages, so efforts are made to avoid the use of such compounds (see Lubricants and Lubrication, Wiley-VCH 2001, T. Mang and W. Dresel, page 191).

In view of the prior art, it is an object of the present invention to provide highly effective, wear-reducing additives which have a low content of undesirable substances, such as, for example, phosphorus and / or sulfur. Overall, the additives should show high environmental compatibility.

Moreover, it was therefore an object of the present invention to provide additives with wear-reducing effect, which can be produced particularly inexpensively.

Furthermore, it was an object of the present invention to provide additives which have a high stability against oxidation and thermal stress as well as a high shear strength. Furthermore, the additives should also be soluble in very non-polar lubricating oils, for example in fully synthetic oils in large quantities. In addition, it was an object of the present invention to provide additives which, in addition to a wear-reducing effect, additionally improve the flow properties of the lubricating oils, ie have a viscosity index-improving effect.

These and other non-explicitly stated objects, which, however, are readily derivable or deducible from the contexts discussed herein by use with all features of claim 1. Advantageous modifications of the inventive use are in the claims based on claim 1 under protection posed.

In that graft copolymers obtainable by a two-stage polymerization, wherein in a first stage at least one graft by free radical polymerization of a monomer composition A), the 0 to 40 wt .-%, based on the weight of the monomer composition A) of one or more ethylenically unsaturated Ester compounds of the formula (I)

wherein R is hydrogen or methyl, R ^{1 is} a linear or branched alkyl radical having 1 to 5 carbon atoms, R ² and R ^{3 are} independently hydrogen or a group of the formula -COOR ', wherein R' is hydrogen or an alkyl group having 1 to 5 carbon atoms means 60 to 100 wt .-%, based on the weight of the monomer composition

A), one or more ethylenically unsaturated ester compounds of the formula (II)

wherein R is hydrogen or methyl, R ^{4 is} a linear or branched alkyl group having 6 to 40 carbon atoms, R ⁵ and R ^{6 are} independently hydrogen or a group of the formula -COOR ", where R" is hydrogen or an alkyl group having 6 to 40 carbon atoms and 0 to 40% by weight, based on the weight of the monomer composition A), of comonomers, and in a second stage a monomer composition B) containing 20 to 100% by weight of at least one monomer wherein the graft copolymer comprises at most 200 ppm sulfur and the ratio of the weight of the monomer composition A) to the weight of the monomer composition B) ranges from 99.7: 0.3 to 80:20 When used to reduce wear in lubricating oil compositions, additives are provided which are particularly inexpensive to manufacture lt can be.

At the same time, a number of further advantages can be achieved by the lubricant composition according to the invention. These include, among others:

The additives to be used according to the present invention show a high stability against oxidation and thermal stress as well as a high shear strength.

The use according to the invention provides additives for reducing wear, which are soluble in very nonpolar lubricating oils, for example in fully synthetic oils in large quantities. Here, the additives show a high compatibility with lubricating oils. As a result of the use according to the invention, additives are provided which, in addition to a wear-reducing effect, additionally improve the flow properties of the lubricating oils, ie have a viscosity index-improving effect.

In addition, the use of the additive according to the invention often reduces energy consumption.

Graft copolymers which are used according to the invention for reducing wear can be obtained by a polymerization comprising at least two steps.

In a first step, usually at least one grafting base can be produced, to which a grafting pad is grafted in at least a second step.

In the context of the present invention, the term "grafting base" denotes at least one polymer onto which side-chain polymers can be grafted. The graft base is also often referred to as main chain polymer, backbone polymer or graft substrate.

In a first step, a monomer composition A) can be radically polymerized, the

0 to 40% by weight, preferably 0.1 to 35 and particularly preferably 1 to 20% by weight, based on the weight of the monomer composition A), of one or more ethylenically unsaturated ester compounds of the formula (I)

wherein R is hydrogen or methyl, R ^{1 is} a linear or branched alkyl radical having 1 to 5 carbon atoms, R ² and R ^{3 are} independently hydrogen or a group of the formula -COOR ', in which R' is hydrogen or an alkyl group having 1 to 5 carbon atoms,

60 to 100% by weight, preferably 65 to 99.9 and particularly preferably 80 to 99% by weight, based on the weight of the monomer composition A), of one or more ethylenically unsaturated ester compounds of the formula (II)

wherein R is hydrogen or methyl, R ^{4 is} a linear or branched alkyl group having 6 to 40 carbon atoms, R ⁵ and R ^{6 are} independently hydrogen or a group of the formula -COOR ", where R" is hydrogen or an alkyl group having 6 to 40 carbon atoms and 0 to 40 wt .-%, based on the weight of the monomer composition A) comprises comonomers.

Monomeric compounds for the preparation of the graft base comprise one or more ethylenically unsaturated ester compounds of the formula (I)

wherein R is hydrogen or methyl, R ^{1 is} a linear or branched alkyl radical having 1 to 5 carbon atoms, R ² and R ^{3 are} independently hydrogen or a group of the formula -COOR ', wherein R' is hydrogen or an alkyl group having 1 to 5 carbon atoms means.

Examples of component a) include

(Meth) acrylates, fumarates and maleates derived from saturated alcohols, such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, n-butyl (meth ) acrylate, tert-butyl (meth) acrylate and

Pentyl (meth) acrylate; Cycloalkyl (meth) acrylates such as cyclopentyl (meth) acrylate; (Meth) acrylates derived from unsaturated alcohols, such as 2-propynyl (meth) acrylate, allyl (meth) acrylate and vinyl (meth) acrylate.

If the term (meth) acrylates is used in the context of the present application, this term encompasses in each case methacrylates or acrylates alone or else mixtures of both.

As a further constituent, the compositions to be polymerized for producing preferred grafting compositions may contain from 60 to 100% by weight, in particular from 65 to 98% by weight and particularly preferably from 70 to 90% by weight, based on the weight of the monomer compositions for the preparation of the graft base, one or more ethylenically unsaturated ester compounds of the formula (II)

wherein R is hydrogen or methyl, R ^{4 is} a linear or branched alkyl group having 6 to 40 carbon atoms, R ⁵ and R ^{6 are} independently hydrogen or a group of the formula -COOR ", where R" is hydrogen or an alkyl group having 6 to 40 carbon atoms means included.

These include, among others

(Meth) acrylates, fumarates and maleates derived from saturated alcohols, such as hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, heptyl (meth) acrylate, 2-tert-butylheptyl (meth) acrylate, octyl ( meth) acrylate, 3-iso-propylheptyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, 5-methylundecyl (meth) acrylate, dodecyl (meth) acrylate, 2-methyldodecyl ( meth) acrylate, tridecyl (meth) acrylate, 5-methyltridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, 2-methylhexadecyl (meth) acrylate, heptadecyl (meth) acrylate, 5-iso-Propylheptadecyl (meth) acrylate, 4-tert-butyloctadecyl (meth) acrylate, 5-ethyloctadecyl (meth) acrylate, 3-iso-propyloctadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate Eicosyl (meth) acrylate, cetyleicosyl (meth) acrylate, stearyl eicosyl (meth) acrylate, docosyl (meth) acrylate and / or eicosyl tetratriacontyl (meth) acrylate; Cycloalkyl (meth) acrylates such as 2,4,5-tri-t-butyl-3-vinylcyclohexyl (meth) acrylate, 2,3,4,5-tetra-t-butylcyclohexyl (meth) acrylate; (Meth) acrylates derived from unsaturated alcohols, such as. B.

Oleyl (meth) acrylate;

Cycloalkyl (meth) acrylates, such as 3-vinylcyclohexyl (meth) acrylate,

Cyclohexyl (meth) acrylate, bornyl (meth) acrylate; as well as the corresponding fumarates and maleates.

The ester compounds having a long-chain alcohol radical, in particular the compounds according to component (b), can be obtained, for example, by reacting (meth) acrylates, fumarates, maleates and / or the corresponding acids with long-chain fatty alcohols, a mixture of esters, such as (Meth) acrylates with different long-chain alcohol radicals is formed. These fatty alcohols include, among others, Oxo Alcohol® 7911, Oxo Alcohol® 7900, Oxo Alcohol® 1100, Alfol® 610, Alfol® 810, Lial® 125, and Nafol® grades (Sasol Olefins & Surfactants GmbH); Aiphanoi® 79 (ICI); Epal® 610 and Epal® 810 (Ethyl Corporation); Linevol® 79, Linevol® 911 and Neodol® 25E (Shell AG); Dehydad®, Hydrenol® and Lorol® types (Cognis); Acropol® 35 and Exxal® 10 (Exxon Chemicals GmbH); Kalcol 2465 (Kao Chemicals).

Of the ethylenically unsaturated ester compounds, the (meth) acrylates are particularly preferred over the maleates and fumarates, ie R ² , R ³ , R ⁵ and R ^{6 of} the formulas (I) and (II) represent hydrogen in particularly preferred embodiments. In general the methacrylates are preferred to the acrylates.

According to a particular aspect of the present invention, preference is given to using mixtures of long-chain alkyl (meth) acrylates according to the component of the formula (II), where the mixtures comprise at least one (meth) acrylate having 6 to 15 carbon atoms in the alcohol radical and at least one (meth) acrylate Have 16 to 40 carbon atoms in the alcohol radical. Preferably, the proportion of (meth) acrylates having 6 to 15 Kohlenstoffomeπ in the alcohol radical in the range of 20 to 95 wt .-%, based on the weight of the monomer composition for the preparation of the graft base. The proportion of (meth) acrylates having 16 to 40 carbon atoms in the alcohol radical is preferably in the range of 0.5 to 60 wt .-%, based on the weight of the monomer composition for the preparation of the graft base.

According to a further aspect of the present invention, the proportion of olefinically unsaturated esters having 8 to 14 carbon atoms is preferably greater than or equal to equal to the proportion of olefinically unsaturated esters having 16 to 18 carbon atoms.

In addition, preferred mixtures for preparing preferred grafting bases may comprise, in particular, ethylenically unsaturated monomers which can be copolymerized with the ethylenically unsaturated ester compounds of the formulas (I) and / or (II). The proportion of comonomers is preferably in the range from 0 to 40 wt .-%, in particular 2 to 35 wt .-% and particularly preferably 5 to 30 wt .-%, based on the weight of the monomer compositions for the preparation of the graft.

Here, comonomers for the polymerization according to the present invention are particularly suitable, which correspond to the formula:

wherein R ^{1 *} and R ^{2 * are} independently selected from the group consisting of hydrogen, halogens, CN, linear or branched alkyl groups having 1 to 20, preferably 1 to 6 and particularly preferably 1 to 4 carbon atoms, which are substituted with 1 to (2n + 1) halogen atoms may be substituted, wherein n is the number of carbon atoms of the alkyl group (for example CF ₃ ), α, ß-unsaturated linear or branched alkenyl or alkynyl groups having 2 to 10, preferably from 2 to 6 and particularly preferably from 2 to 4 carbon atoms, which may be substituted with 1 to (2n-1) halogen atoms, preferably chlorine, wherein n is the number of carbon atoms of the alkyl group, for example CH ₂ = CCI-, cycloalkyl groups having 3 to 8 carbon atoms, with 1 to (2n-1) halogen atoms, preferably chlorine, may be substituted, wherein n is the number of carbon atoms of the cycloalkyl group; Aryl groups of 6 to 24 carbon atoms which may be substituted with 1 to (2n-1) halogen atoms, preferably chlorine, and / or alkyl groups of 1 to 6 carbon atoms, where n is the number of carbon atoms of the aryl group; C (= Y ^* ) R ^{5 *} , C (= Y ^* ) NR ^{6 *} R ^{7 *} , Y ^* C (= Y *) R ^{5 *} , SOR ^{5 *} , SO ₂ R ^{5 *} , OSO ₂ R ^{5 *} , NR ^{8 *} SO ₂ R ^{5 *} , PR ^{5 *} _2l P (= Y ^* ) R ^{5 *} 2, Y ^* PR ^{5 *} ₂ , Y ^* P (= Y ^* ) R ^{5 *} ₂ , NR ^{8 *} ₂ which may be quaternized with an additional R ^{8 *} , aryl or heterocyclyl group, where Y * NR ^{8 *} , S or O, preferably O may be; R ^{5 * is} an alkyl group having 1 to 20 carbon atoms, an alkylthio having 1 to 20 carbon atoms, OR ¹⁵ (R ¹⁵ is hydrogen or an alkali metal), alkoxy of 1 to 20 carbon atoms, aryloxy or heterocyclyloxy; R ^{6 *} and R ^{7 * are} independently hydrogen or an alkyl group having 1 to 20 carbon atoms, or R ^{6 *} and R ^{7 *} may together form an alkylene group having 2 to 7, preferably 2 to 5 carbon atoms to form a 3 to 8 membered, preferably 3 to 6 membered ring, and R ^{8 * are} hydrogen, linear or branched alkyl or aryl groups of 1 to 20 carbon atoms;

R ^{3 *} and R ^{4 * are} independently selected from the group consisting of hydrogen, halogen (preferably fluoro or chloro), alkyl groups of 1 to 6 carbon atoms and COOR ^{9 *} , where R ^{9 * is} hydrogen, an alkali metal or an alkyl group of 1 to 40 Carbon atoms, or R ^{3 *} and R ^{4 *} may together form a group of formula (Ch 1) _n ¹ which may be substituted with 1 to 2n 'halogen atoms or C 1 to C ₄ alkyl groups, or of formula C (= O) -Y * -C (= O) where n 'is from 2 to 6, preferably 3 or 4, and Y * is as previously defined; and wherein at least 2 of the radicals R ^{1 *} , R ^{2 *} , R ^{3 *} and R ^{4 * are} hydrogen or halogen.

Preferred comonomers which may be included in the monomer compositions A) include nitrogen-bearing monomers, which correspond to the monomers contained in the monomer composition B).

Preferred comonomers include, but are not limited to, vinyl halides such as vinyl chloride, vinyl fluoride, vinylidene chloride, and vinylidene fluoride;

Vinyl esters, such as vinyl acetate;

Styrene, substituted styrenes having an alkyl substituent in the side chain, such as. B. α-methylstyrene and α-ethyl styrene, substituted styrenes having an alkyl substituent on the ring, such as vinyltoluene and p-methylstyrene, halogenated styrenes, such as monochlorostyrenes, dichlorostyrenes, tribromostyrenes and tetrabromostyrenes;

Heterocyclic vinyl compounds, such as 2-vinylpyridine, 3-vinylpyridine, 2-methyl-5-vinylpyridine, 3-ethyl-4-vinylpyridine, 2,3-dimethyl-5-vinylpyridine, vinylpyrimidine, vinylpipehdine, 9-vinylcarbazole, 3-vinylcarbazole, 4-vinylcarbazole, 1-vinylimidazole, 2-methyl-1-vinylimidazole, N-vinylpyrrolidone, 2-vinylpyrrolidone, N-vinylpyrrolidine, 3-vinylpyrrolidine, N-vinylcaprolactam, N-vinylbutyrolactam, vinyloxolane, vinylfuran, vinyloxazoles and hydrogenated vinyloxazoles;

Vinyl and isoprenyl ethers;

Maleic acid and maleic acid derivatives, such as maleic anhydride,

Methylmaleic anhydride, maleimide, methylmaleimide;

Fumaric acid and fumaric acid derivatives; Acrylic acid and methacrylic acid; Dienes such as Diviπylbenzol;

Aryl (meth) acrylates, such as benzyl methacrylate or

Pheπylmethacrylat, wherein the aryl radicals may each be unsubstituted or substituted up to four times;

Methacrylates of halogenated alcohols, such as

2,3-Dibromopropylmethacrylat,

4-Bromophenylmethacrylat,

1, 3-dichloro-2-propyl methacrylate,

2-Bromoethylmethacrylat,

2-lodoethylmethacrylat,

Chloromethylmethacrylat;

Hydroxyalkyl (meth) acrylates, such as

3-hydroxypropyl methacrylate,

3,4-dihydroxybutyl,

2-hydroxyethyl methacrylate,

2-hydroxypropyl methacrylate,

2,5-dimethyl-1,6-hexanediol (meth) acrylate,

1, 10-decanediol (meth) acrylate;

carbonyl-containing methacrylates, such as

2-carboxyethyl methacrylate,

Carboxymethylmethacrylat,

oxazolidinylethyl,

N- (methacryloyloxy) formamide,

Acetonylmethacrylat,

N-methacryloylmorpholine,

N-methacryloyl-2-pyrrolidinone,

N- (2-methacryloyloxyethyl) -2-pyrrolidinone,

N- (3-methacryloyloxypropyl) -2-pyrrolidinone, N- (2-methacryloyloxypentadecyl) -2-pyrrolidinone, N- (3-methacryloyloxyheptadecyl) -2-pyrrolidinone;

Glycol dimethacrylates, such as 1,4-butanediol methacrylate, 2-butoxyethyl methacrylate,

2-Ethoxyethoxymethylmethacrylat,

2-ethoxyethyl;

Methacrylates of ether alcohols, such as

tetrahydrofurfuryl,

Vi π yl oxyeth oxyeth y I methacrylate,

methoxyethoxyethyl,

1-butoxypropyl methacrylate,

1-methyl (2-vinyloxy) ethyl methacrylate,

Cyclohexyloxymethylmethacrylat,

Methoxymethoxyethylmethacrylat,

Benzyloxymethylmethacrylat,

furfuryl,

2-butoxyethyl methacrylate,

2-Ethoxyethoxymethylmethacrylat,

2-ethoxyethyl methacrylate,

Allyloxymethylmethacrylat,

1-ethoxybutyl methacrylate,

methoxymethyl,

1-ethoxyethyl methacrylate,

Ethoxymethyl methacrylate and ethoxylated (meth) acrylates which preferably have 1 to 20, in particular 2 to 8, ethoxy groups;

Aminoalkyl (meth) acrylates and aminoalkyl (meth) acrylatamides, such as

N- (3-dimethylaminopropyl) methacrylamide,

dimethylaminopropyl,

3-Diethylaminopentylmethacrylat,

3-Dibutylaminohexadecyl (meth) acrylate;

Nitriles of (meth) acrylic acid and other nitrogen-containing methacrylates, such as

N- (methacryloyloxyethyl) diisobutylketimin,

N- (methacryloyloxyethyl) dihexadecylketimin,

methacryloylamidoacetonitrile,

2-Methacryloyloxyethylmethylcyanamid,

cyanomethyl; heterocyclic (meth) acrylates, such as 2- (1-imidazolyl) ethyl (meth) acrylate, 2- (4-morpholinyl) ethyl (meth) acrylate and 1- (2-methacryloyloxyethyl) -2-pyrrolidone;

Oxiranyl methacrylates, as

2,3-epoxybutyl methacrylate,

3,4-epoxybutyl,

10,11 -epoxyundecyl methacrylate,

2,3-epoxycyclohexyl methacrylate,

10,11-Epoxyhexadecylmethacrylat ;; Glycidyl.

These monomers can be used singly or as a mixture.

The graft layer preferably has a specific viscosity η _{sp / c} measured in chloroform at 25 ° C. in the range from 4 to 60 ml / g, particularly preferably in the range from 5 to 40 ml / g, measured according to ISO 1628-6.

The weight average molecular weight of the graft base is generally less than or equal to 600,000 g / mol, preferably less than or equal to 400,000 g / mol. Preferably, the weight-average molecular weight of the grafting base is in the range of 5,000 to 200,000, in particular 6,000 to 100,000 g / mol.

The preferred grafting bases which can be obtained by polymerization of unsaturated ester compounds preferably have a polydispersity M _w / M _n in the range of 1, 1 to 10.0, in particular 1, 2 to 7.0 and particularly preferably 1, 3 to 5 , 0 on.

The molecular weight and the polydispersity can be determined by known methods. For example, gel permeation chromatography (GPC) can be used. Likewise, an osmometric method, such as, for example, "vapor phase osmometry" can be used to determine the molecular weights. [Die Die] The methods mentioned are described, for example, in: PJ Flory, "Phnciples of Polymer Chemistry" Cornell University Press (1953), Chapter VII, 266- 316, as well as "Macromeolecules, to Introduction to Polymer Science", FA Bovey and FH Winslow, Editors, Academic Press (1979), 296-312 and WW Yau, JJ Kirkland and DD BIy, "Modern Size Exclusion Liquid Chromatography, John Wiley and Sons, New York, 1979. Gel permeation chromatography is preferred for determining the molecular weights of the polymers presented herein, and should preferably be measured against polymethyl acrylate or polyacrylate standards.

The usual free-radical polymerization is described, inter alia, in Ullmanns's Encyclopedia of Industrial Chemistry, Sixth Edition. In general, a polymerization initiator and a chain transfer agent are used for this purpose.

Useful initiators include the azo initiators well known in the art, such as AIBN and 1, 1-azobiscyclohexanecarbonitrile, and peroxy compounds such as methyl ethyl ketone peroxide, acetylacetone peroxide, dilauryl peroxide, tert-butyl per-2-ethylhexanoate, ketoperoxide, tert-butyl peroctoate, methyl isobutyl ketone peroxide , Cyclohexanone peroxide, dibenzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl carbonate, 2,5-bis (2-ethylhexanoylperoxy) -2,5-dimethylhexane, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxy-3, 5,5-trimethylhexanoate, dicumyl peroxide, 1,1-bis (tert-butylperoxy) cyclohexane, 1,1-bis (tert-butylperoxy) 3,3,5-trimethylcyclohexane, cumyl hydroperoxide, tert-butyl hydroperoxide, bis (4 tert-butylcyclohexyl) peroxydicarbonate, mixtures of two or more of the abovementioned compounds with one another, and mixtures of the abovementioned compounds with unspecified compounds which can likewise form free radicals.

Suitable chain transfer agents are, in particular, sulfur-free compounds which are known per se. These include, for example, without this being a limitation, dimeric α-methylstyrene (2,4-diphenyl-4-methyl-1-pentene), enol ethers of aliphatic and / or cycloaliphatic aldehydes, terpenes, α-terpinene, terpinolene, 1, 4 -Cyclohexadiene, 1, 4-dihydronaphthalene, 1, 4,5,8-tetrahydronaphthalene, 2,5-dihydrofuran, 2,5-dimethylfuran and / or 3, 6-dihydro-2H-pyran, preferred is dimeric α-methylstyrene.

These chain transferers are commercially available. However, they can also be produced in a manner known to the person skilled in the art. Thus, the preparation of dimeric α-methylstyrene in the patent DE 966 375 is described. Enol ethers of aliphatic and / or cycloaliphatic aldehydes are disclosed in the patent DE 3 030 373. The representation of terpenes is explained in EP 80 405. Offenlegungsschriftenπ JP 78/121 891 and JP 78/121 890 illustrate the preparation of α-terpinene, terpinolene, 1, 4-cyclohexadiene, 1, 4-dihydronaphthalene, 1, 4,5,8-tetrahydronaphthalene. The preparation of 2,5-dihydrofuran, 2,5-dimethylfuran and 3,6-dihydro-2H-pyran is described in the published patent application DE 2 502 283.

The polymerization of the graft base can be carried out at atmospheric pressure, sub-od. Overpressure. The polymerization temperature is not critical. In general, however, it is in the range of -20 ° - 200 ⁰ C, preferably 0 ° - 130 ⁰ C and particularly preferably 70 ° - 120 ° C. The polymerization can be carried out with or without solvent. The term of the solvent is to be understood here broadly.

Preferably, the polymerization is carried out in a nonpolar solvent. These include hydrocarbon solvents such as aromatic solvents such as toluene, benzene and xylene, saturated hydrocarbons such as cyclohexane, heptane, octane, nonane, decane, dodecane, which may also be branched. These solvents can be used individually or as a mixture. Particularly preferred solvents are mineral oils, natural oils and synthetic oils and mixtures thereof. Of these, mineral oils are most preferred.

The preparation of the graft base can be carried out in one or more steps, wherein different monomer compositions A) can be used, which may differ, for example, in the content of comonomers. As a result, mixtures of graft bases can be produced, which can advantageously be used according to the invention.

To prepare graft copolymers of the composition obtained in step 1, which generally comprises at least one backbone polymer, at least one monomer composition B) is grafted.

Side chains are believed to be formed by the grafting on the grafting base so that at least a portion of the grafting pad is covalently bound to the grafting base.

The grafting can be done in one or more steps. Here, inter alia, the composition of the monomer composition B) can be changed. For example, different monomers can be used with nitrogen-containing groups.

In addition, compositions can be grafted in other stages, which no or only a small proportion of nitrogen-containing Have monomers. Such grafts may be carried out before or after grafting with monomers containing nitrogen-containing groups.

The performance of graft copolymerizations is well known and set forth, for example, in Ullmann's Encyclopedia of Industrial Chemistry, Sixth Edition and in Römpp Chemie-Lexikon on CD Version 2.0, reference being made to further literature.

The monomer composition B) comprises at least 20 wt .-%, preferably at least 50 wt .-%, in particular at least 70 wt .-% and particularly preferably 90 wt .-% to 100 wt .-%, based on the weight of the monomer composition B) , at least one monomer having at least one nitrogen-containing group.

The ratio of the weight of the monomer composition A) to the weight of the monomer composition B) is in the range of 99.7: 0.3 to 80:20, preferably in the range of 99.5: 0.5 to 88:12, in particular in the range of 99: 1 to 91: 9 and more preferably in the range of 98: 2 to 95: 5.

In general, from 0.3 to 12% by weight, in particular from 1 to 9% by weight and preferably from 2 to 5% by weight, based on the weight of the graft base, of one or more monomers having at least one nitrogen-containing group can be grafted onto the graft base ,

Monomers having at least one nitrogen-containing group are well known. Preferably, the nitrogen-containing groups have a dispersing action. Further, preferred nitrogen-containing groups contained in the monomers exhibit a basic action. The pK _b value of these bases is preferably in the range of 2 to 7, more preferably 4 to 7. Preferred groups are primary, secondary or tertiary amines, saturated and / or unsaturated heterocyclic nitrogen compounds, such as pyridine, pyrimidine, piperidine, carbazole, imidazole, morpholine, pyrrole.

Preferred monomers having at least one nitrogen-containing group are compounds of the formula (III)

wherein R ⁷ , R ⁸ and R ⁹ independently of one another may be hydrogen or an alkyl group having 1 to 5 carbon atoms and R ^{10 is} a group containing 1 to 100 carbon atoms and having at least one nitrogen atom. Preferably, at least two of R ⁷ , R ⁸ and R ^{9 are} hydrogen.

The radical R ¹⁰ represents a group comprising 1 to 100, in particular 2 to 50, preferably 2 to 20 carbon atoms. The term t to 100 carbon atoms-containing group "denotes radicals of organic compounds having 1 to 100 carbon atoms and comprises aromatic and heteroaromatic groups and Alkyl, cycloalkyl, alkoxy, cycloalkoxy, alkenyl, alkanoyl, alkoxycarbonyl and heteroaliphatic groups, in which the groups mentioned can be branched or unbranched, furthermore these groups can have customary substituents, substituents being, for example, linear and branched alkyl groups with 1 to 6 carbon atoms, such as, for example, methyl, ethyl, propyl, butyl, pentyl, 2-methylbutyl or hexyl; cycloalkyl groups, such as cyclopentyl and cyclohexyl; aromatic groups, such as phenyl or naphthyl; amino groups, ether groups, ester groups and halides.

According to the invention, aromatic groups are radicals of mononuclear or polynuclear aromatic compounds having preferably 6 to 20, in particular 6 to 12, carbon atoms. Heteroaromatic groups denote aryl radicals in which at least one CH group has been replaced by N and / or at least two adjacent CH groups have been replaced by NH or O, heteroaromatic groups having from 3 to 19 carbon atoms.

Preferred aromatic or heteroaromatic groups according to the invention are derived from benzene, naphthalene, biphenyl, diphenyl ether, diphenylmethane, Diphenyldimethylmethane, bisphenone, furan, pyrrole, imidazole, isoxazole, pyrazole, 1, 3,4-oxadiazole, 2,5-diphenyl-1, 3,4-oxadiazole, 1, 3,4-triazole, 2,5-diphenyl- 1, 3,4-triazole, 1, 2,5-triphenyl-1, 3,4-triazole, 1, 2,4-oxadiazole, 1, 2,4-triazole, 1, 2,3-triazole, 1, 2,3,4-tetrazole, benzo [b] furan, indole, benzo [c] furan, isoindole, benzoxazole, benzimidazole, benzisoxazole, benzopyrazole, dibenzofuran, carbazole, pyridine, bipyridine, pyrazine, pyrazole, pyrimidine, pyridazine, 1, 3,5-triazine, 1, 2,4-triazine, 1, 2,4,5-triazine, tetrazine, quinoline, isoquinoline, quinoxaline, quinazoline, cinnoline, 1,8-naphthyridiene, 1,5-naphthyridine, 1, 6-naphthyridiπ, 1, 7-naphthyridine, phthalazine, pyridopyrimidine, purine, pteridine or quinolizine, 4H-quinolizine, diphenyl ether, anthracene, benzopyrrole, benzooxathiadiazole, benzooxadiazole, benzopyridine, benzopyrazine, benzopyrazidine, benzopyrimidiπ, beπzotriazine, indolizine, pyridopyridine, imidazopyrimidine, Pyrazinopyrimidine, carbazole, adridine, phenazine, benzoquinoline, phenoxa zin, acridizine, benzopteridine, phenanthroline and Phenaπthren, which may optionally be substituted.

The preferred alkyl groups include the methyl, ethyl, propyl, isopropyl, 1-butyl, 2-butyl, 2-methyl propyl, tert-butyl, pentyl, 2-methylbutyl, 1, 1 - Di methyl propyl, hexyl, heptyl, octyl, 1, 1, 3,3-tetramethylbutyl, nonyl, 1-decyl, 2-decyl, undecyl, dodecyl, pentadecyi and the eicosyl Group.

Preferred cycloalkyl groups include the cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups, optionally substituted with branched or unbranched alkyl groups.

The preferred alkenyl groups include the vinyl, allyl, 2-methyl-2-propene, 2-butenyl, 2-pentenyl, 2-decenyl and 2-eicosenyl groups.

The preferred alkynyl groups include the ethynyl, propargyl, 2-methyl-2-propyne, 2-butynyl, 2-pentynyl and 2-decynyl groups.

Preferred alkanoyl groups include the formyl, acetyl, propionyl, 2-methylpropionyl, butyryl, valeroyl, pivaloyl, hexanoyl, decanoyl and dodecanoyl groups.

Preferred alkoxycarbonyl groups include the methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, tert-butoxycarbonyl group, Hexyloxycarbonyl, 2-methylhexyloxycarbonyl, decyloxycarbonyl or dodecyloxycarbonyl group.

The preferred alkoxy groups include alkoxy groups whose hydrocarbon radical is one of the aforementioned preferred alkyl groups.

Preferred cycloalkoxy groups include cycloalkoxy groups whose hydrocarbon radical is one of the aforementioned preferred cycloalkyl groups.

The preferred heteroatoms contained in R ¹⁰ include, among others, oxygen and nitrogen.

According to a particular aspect of the present invention, the group R ^{10 may represent} a group -C (O) -XR ¹¹ , with X = oxygen or an amino group of the formula -NH- or -NR ¹² -, in which R ^{12 is} an alkyl radical with 1 to 40 carbon atoms, and R ^{11 is} a substituted with at least one -NR ¹³ R ¹⁴ group linear or branched alkyl radical having 2 to 20, preferably 2 to 6 carbon atoms, wherein R ¹³ and R ¹⁴ independently of one another represent hydrogen, an alkyl radical with 1 to 20, preferably 1 to 6 or in which R ¹³ and R ¹⁴ form a 5- or 6-membered ring, which may optionally be substituted by C 1 -C 6 -alkyl, including the nitrogen atom and optionally a further nitrogen or oxygen atom,

In another preferred embodiment, R ^{10 may represent} a group -NR ¹⁵ C (= O) R ¹⁶ , wherein R ¹⁵ and R ¹⁶ together form an alkylene group of 2 to 6, preferably 2 to 4, carbon atoms, wherein they are 4 to 8 membered , preferably 4 to 6-membered saturated or unsaturated ring form, optionally with the inclusion of another nitrogen or oxygen atom, said ring may be optionally substituted with C 1 -C 6 -alkyl.

According to a third preferred embodiment, R ^{10 may represent} a group which is different from the previously described heteroaromatic or heterocyclic Derived compounds. Preferred compounds here include pyridine, pyrimidine, piperidine, carbazole, imidazole, morpholine, pyrrole

The ratio of nitrogen atoms to carbon atoms in the radical R ^{10 of} the formula (III) may, according to a particular aspect, be in the range from 1: 1 to 1:20, preferably 1: 2 to 1:10.

Among the preferred monomers having at least one nitrogen-containing group include, inter alia

Aminoalkyl (meth) acrylates and aminoalkyl (meth) acrylatamides, such as

N- (3-dimethylaminopropyl) methacrylamide,

dimethylaminoethyl

dimethylaminopropyl,

3-Diethylaminopentylmethacrylat,

3-Dibutylaminohexadecyl (meth) acrylate; heterocyclic (meth) acrylates, such as 2- (1-imidazolyl) ethyl (meth) acrylate, N-morpholinoethyl (meth) acrylate, in particular 2- (4-morpholinyl) ethyl (meth) acrylate and 1- (2-methacryloyloxyethyl) - 2-pyrrolidone;

heterocyclic vinyl compounds such as 2-vinylpyridine, 3-vinylpyridine, 2-methyl-5-vinylpyridine, 3-ethyl-4-vinylpyridine, 2,3-dimethyl-5-vinylpyridine, vinylpyrimidine, vinylpiperidine, 9-vinylcarbazole, 3-vinylcarbazole, 4-vinyl carbazole, 1-vinylimidazole, 2-methyl-1-vinylimidazole, N-vinylpyrrolidone, 2-vinylpyrrolidone, N-vinylpyrrolidine, 3-vinylpyrrolidine, N-vinylcaprolactam, N-vinylbutyrolactam, vinyloxazoles and hydrogenated vinyloxazoles.

These monomers can be used singly or as a mixture.

Further, the monomer composition B) may have comonomers which may be copolymerized with the monomers having at least one nitrogen-containing group. These monomers correspond to the monomers set forth with respect to the monomer composition A). These monomers can be used singly or as a mixture. For grafting, a polymerization initiator is generally used, it being possible to use the initiators mentioned above for the preparation of the graft base. Cumyl hydroperoxide, diisobutyl hydroperoxide or tert-butyl perbenzoate can be used with particular preference.

The present invention provides additives for reducing wear without having a high sulfur content. Thus, the sulfur content is at most 200 ppm, preferably at most 100 ppm and more preferably at most 5 ppm, based on the weight of the graft copolymer. The low proportion of sulfur can be achieved in particular by the use of sulfur-free components.

The grafting can be carried out under normal pressure, under- or overpressure. The polymerization temperature is not critical. In general, however, it is in the range of -20 ° - 200 ⁰ C, preferably 0 ° - 160 ⁰ C and particularly preferably 110 ° - 140 ⁰ C.

According to a particular aspect of the present invention, the graft polymerization may be carried out at a temperature higher than the temperature at which the grafting base was formed. Preferably, in this case the temperature of the grafting by at least 5 ° C, preferably at least 10 ⁰ C and particularly preferably at least 2O ⁰ C higher than the temperature at which the backbone was formed.

In a particular aspect the present invention, the graft yield being greater than or equal to (x ^* 10 ^-5 mol / g + 35)%, particularly preferably greater than or equal to (x ^* 10 ^"5 mol / g + 40)%, where x is the after In the case of a weight-average molecular weight of 100,000, it follows that the grafting yield is preferably greater than or equal to 36% and particularly preferably greater than or equal to 41%. According to a particular aspect of the present invention, the graft yield is greater than or equal to 35%, in particular greater than or equal to 45% and particularly preferably greater than or equal to 50%.

The graft yield (PA) is defined as PA = (M _P rM _PG ) / Mw ^* 100%, where M _{PG is} the mass of the graft base and M _{Pf is} the mass of the graft copolymer in a unit volume.

The mass of the graft base (Mp _G ) and the mass of the graft copolymer (MPO can be determined by HPLC chromatography (High Performance Liquid Chromatography), which is carried out as adsorption chromatography.

For elution, the polarity of the solvent is varied. This can be achieved by changing the solvent composition. Preferably, a Hewlett Packard HP 1090 liquid chromatograph with a CN-functionalized silica gel column (Nucleosil CN-25 cm # NI224) is used.

For the elution, a solvent gradient is preferably used. This can be eluted over 15 minutes. Pure isooctane is used in the first minute. In the range from minute 1 to minute 11, the isooctane content is reduced from 100% to 0% with a constant gradient, whereby the content of tetrahydrofuran and methanol is increased from 0% to 50% with a constant gradient. In the range of minute 11 to minute 15, the content of methanol is increased from 50% to 100%, whereby the content of tetrahydrofuran is reduced from 50% to 0%. The preferred solvent composition for elution can be seen in Figure 1. The HPLC analysis is preferably carried out at a flow rate of 1 ml / min at room temperature. The HPLC column can be charged with as high a loading as possible, ensuring that the entire polymer is bound to the column. In the case of HPLC, the graft base is generally eluted before the graft copolymer.

The detection of the polymers is preferably carried out by the ELSD method (Evaporating Light Scattering Detector), which is known per se and in the above cited literature is described. In order to convert the measured units into mass units, a calibration function is required, which should preferably take place immediately before or after the measurement. An Alltech 2000 ELSD detector can be used here.

As previously stated, the graft yield is given by the equation PA = (Mpr

The mass of the graft copolymer (M _Pf) results from the difference of the total mass of the polymer (M _tal) and the mass of the graft M _PG according to the equation M = Mpf _tal - M _PG.

The total mass of the polymer (M _Gesa mt) can be determined in a known manner, for example by weighing the polymer used for analysis or from the density, the weight fraction and the volume of the polymer solution used for analysis.

The mass of the graft base (M _PG ) results from

M-PG - ([mALf dt) ^* f

in which

mAU * dt ¹ : peak area of the grafting base in miliabsorbance units * seconds = mAlTs over the time span t1 to t2, where t1 is the beginning and t2 is the

End of the elution grafting constitute.

^j f ^reφ _θπ * ^e _: response factor, function in μg / mAU * s, used to convert the

Peak area is required in a mass, which is obtained via a calibration curve. The graft copolymer preferably has a specific viscosity η _{sp / c} measured in chloroform at 25 ° C. in the range from 5 to 70 ml / g, particularly preferably in the range from 6 to 50 ml / g, measured according to ISO 1628-6.

Preferably, the ratio of the specific viscosity of the graft copolymer to the specific viscosity η of the graft base is in the range from 1:01 to 1 to 1, 30: 1, in particular in the range from 1, 10: 1 to 1, 20: 1.

The weight-average molecular weight of the graft copolymer is preferably less than or equal to 600,000 g / mol, especially less than or equal to 400,000 g / mol. Particularly preferably, the weight-average molecular weight of the graft copolymer is in the range from 5100 to 250,000, in particular 6500 to 120,000 g / mol.

Preferably, the ratio of the weight average molecular weight of the graft copolymer to the weight average molecular weight of the grafting base is in the range of 1:01: 1 to 5: 1, more preferably in the range of 1: 5: 1 to 2: 1.

Furthermore, the graft copolymer is used in a lubricating oil composition. A lubricating oil composition comprises at least one lubricating oil.

The lubricating oils include, in particular, mineral oils, synthetic oils and natural oils.

Mineral oils are known per se and commercially available. They are generally obtained from petroleum or crude oil by distillation and / or refining and, if appropriate, further purification and refining processes, the term "mineral oil" in particular falling to the relatively high-boiling fractions of crude oil or crude oil. In general, the boiling point of mineral oil is higher than 200 ^° C., preferably higher than 300 ^° C., at 5000 Pa. The production by smoldering of shale oil, coking of hard coal, distillation under exclusion of lignite and hydration of coal or lignite is also possible. To a small extent, mineral oils are also made from plant-based raw materials (eg from jojoba, rapeseed) or animal (eg claw oil) origin. Accordingly, mineral oils, depending on the origin of different proportions of aromatic, cyclic, branched and linear hydrocarbons.

In general, a distinction is made between paraffin-based, naphthenic and aromatic fractions in crude oils or mineral oils, the terms paraffin-based fraction being longer-chain or highly branched isoalkanes and naphthenic fraction being cycloalkanes. In addition, mineral oils, depending on their origin and refinement, have different proportions of n-alkanes, isoalkanes with a low degree of branching, so-called monomethyl-branched paraffins, and compounds with heteroatoms, in particular O, N and / or S, which are attributed to polar properties , The assignment is difficult, however, since individual alkane molecules can have both long-chain branched groups and cycloalkane radicals and aromatic moieties. For the purposes of the present invention, the assignment can be made, for example, according to DIN 51 378. Polar proportions may also be determined according to ASTM D 2007.

The proportion of n-alkanes in preferred mineral oils is less than 3 wt .-%, the proportion of O, N and / or S-containing compounds less than 6 wt .-%. The proportion of aromatics and monomethyl branched paraffins is generally in the range of 0 to 40 wt .-%. According to an interesting aspect, mineral oil mainly comprises naphthenic and paraffinic alkanes, which generally have more than 13, preferably more than 18 and most preferably more than 20 carbon atoms. The proportion of these compounds is generally> 60 wt .-%, preferably> 80 wt .-%, without this being a restriction. A preferred mineral oil contains from 0.5 to 30% by weight of aromatic fractions, from 15 to 40% by weight of naphthenic fractions, from 35 to 80% by weight of paraffinic fractions, up to 3% by weight of n-alkanes and 0.05% to 5 wt .-% polar compounds, each based on the total weight of the mineral oil.

An analysis of particularly preferred mineral oils, which was carried out by conventional methods, such as urea separation and liquid chromatography on silica gel, shows, for example, the following constituents, the percentages being based on the total weight of the particular mineral oil used: n-alkanes having about 18 to 31 C Atoms: 0.7 - 1, 0%, low branched alkanes with 18 to 31 C atoms:

1, 0 - 8.0%,

Aromatics with 14 to 32 C atoms:

0.4-10.7%,

Iso- and cycloalkanes with 20 to 32 carbon atoms:

60.7- 82.4%, polar compounds:

0.1 - 0.8%,

Loss:

6.9 - 19.4%.

Valuable advice regarding the analysis of mineral oils and a list of mineral oils which have a different composition can be found for example in Ullmann's Encyclopedia of Industrial Chemistry, ^5th Edition on CD-ROM, 1997, keyword "lubricants and related products".

Synthetic oils include, but are not limited to, organic esters such as diesters and polyesters, polyalkylene glycols, polyethers, synthetic hydrocarbons, especially polyolefins, of which polyalphaolefins (PAO) are preferred, silicone oils and perfluoroalkyl ethers. They are usually slightly more expensive than the mineral oils, but have advantages in terms of their performance.

Natural oils are animal or vegetable oils, such as claw oils or jojoba oils.

These lubricating oils can also be used as mixtures and are often commercially available.

The concentration of the graft copolymer in the lubricating oil composition is preferably in the range of 1 to 40% by weight, more preferably in the range of 2 to 20% by weight, based on the total weight of the composition.

Besides the aforementioned components, a lubricating oil composition may contain other additives and additives.

These additives include antioxidants, corrosion inhibitors, anti-foaming agents, anti-wear components, dyes, color stabilizers, detergents, pour point depressants, Dl additives, friction modifiers and / or extreme pressure additives. The graft copolymer can be used in particular for reducing wear in internal combustion engines, gearboxes, couplings or pumps.

According to a particular aspect of the present invention, the present use may result in a mean cam wear of at most 40 μm, preferably at most 30 μm and more preferably at most 20 μm after 100 hours measured according to CEC-L-51-A-98.

Examples

Methods used or test methods:

In general, the determination of wear in the engine by a component comparison before and after wear test by measuring the cam shape. For the present invention, the test method CEC-L-51-A-98 was measured. This test method is suitable both for the investigation of the wear behavior in a car diesel engine (ACEA category B) and in a truck diesel engine (ACEA category E).

In these test methods, the circumferential profile of each cam is determined and compared in 1 ° increments on a 2- or 3-D measuring machine before and after testing. The profile deviation created in the test corresponds to the cam wear. To evaluate the tested engine oil, the wear results of the individual cams are averaged and compared with the limit of the corresponding ACEA categories.

Deviating from the CEC test specification, the test duration was shortened from 200h to 100h. After this test, the cam wear was determined. After only 100 hours, clear differences in wear between the formulations used were found. Synthesis of the Polymer Used for Example 1 (Polymer Composition I)

In a 2 liter four-necked flask equipped with saber stirrer (operated at 150 revolutions per minute), thermometer and reflux condenser 430 g of a 150N oil and 47.8 g of a monomer mixture consisting of C12-C18 alkyl methacrylates and methyl methacrylate (MMA) in a weight ratio 99,0: 1, 0 submitted. The temperature is set to 100 ⁰ C. Thereafter, 0.77 g of tert-butyl peroctoate are added and at the same time a Moπomerzulauf consisting of 522.2 g of a mixture of C12-C18-alkyl methacrylates and methyl methacrylate in a weight ratio 99.0: 1, 0 and 3.92 g tert-butyl peroctoate started. The feed time is 3.5 hours and the feed rate is uniform. 2 hours after the end of the feed, another 1.14 g of tert-butyl peroctoate are added. The total reaction time is 8 hours. Thereafter, the batch is heated to 130 ⁰ C. After reaching the 130 ⁰ C 13.16 g of a 150N oil, 17.45 g of N-vinylpyrrolidone and 1, 46 g tert-butyl perbenzoate are added. In each case 1 hour, 2 hours and 3 hours thereafter each 0.73 g of tert-butyl perbenzoate are added. The total reaction time is 8 hours. Thereafter, the polymer solution is added to a pour point improver, which constitutes 7% by weight of the total solution.

Specific viscosity (20 ^° C. in chloroform): 29 ml / g

• Kinematic viscosity at 100 ⁰ C: 492 mm7s

• thickening effect (10% of the above product in a 150N oil) at 100 ° C: 10.97 mm ² / s at 4O ⁰ C: 64.3 mm ² / s

• viscosity index: 164

Residual monomer content C12-18-alkyl methacrylate: 0.24%

• residual monomer content MMA: 22 ppm

Residual monomer content N-vinylpyrrolidone: 0, 056%

The graft yield was 55%. Synthesis of the Polymer Used for Comparison 2 (Polymer Composition II)

In a 2-liter four-necked flask equipped with saber stirrer (operated at 150 rpm), thermometer and reflux condenser, 400 g of a 150N oil and 44.4 g of a monomer mixture consisting of C12-C18 alkyl methacrylates, methyl methacrylate (MMA) and a methacrylate ester an iso-C13-alcohol with 20 ethoxylate units in the weight ratio 87.0 / 0.5 / 12.5 submitted. The temperature is set to 90 ^° C. After reaching the 90 ⁰ C 1, 75 g of tert-butyl peroctoate are added and simultaneously a feed of 555.6 g of a mixture consisting of C12-C18-alkyl methacrylates, methyl methacrylate and a methacrylate ester of an iso-C13-alcohol with 20 ethoxylate units in Weight ratio 87.0 / 0.5 / 12.5 and 2.78 g tert-butyl peroctoate started. The feed time is 3.5 hours. The feed rate is even. 2 hours after the end of the feed, another 1.20 g of tert-butyl peroctoate are added. The total reaction time is 8 hours. Thereafter, the polymer solution is added to a pour point improver, which is then present at 5% by weight. Thereafter, the solution is diluted 79/21 with an ethoxylated iso-C13 alcohol containing 3 ethoxylate units.

Specific viscosity (20 ^° C. in chloroform): 45 ml / g

• Kinematic viscosity at 100 ^° C.: 400 mm ² / s

• thickening effect (10% of the above solution in a 150N oil) at 100 ° C: 11 56 mm ² / s at 40 ⁰ C: 63.9 mm ² / s

Viscosity index: 178

Residual monomer content C12-18-alkyl methacrylate: 0.59%

• residual monomer content MMA: 48 ppm Comparative Example 1

As Comparative Example 1, a motor oil formulation of the category SAE 5W-30 consisting of a commercially available base oil and additives such as e.g. OLOA 4594 (DI package) and Nexbase 3043 mixed as an oil component and tested in the CEC-L-51 -A-98 test.

Oloa 4549 (Oronite) is a typical Dl additive for engine oils. In addition to ashless dispersants, the product also contains components to improve the wear behavior. The latter components in Oloa 4549 are zinc- and phosphorus-containing compounds. Zinc- and phosphorus-containing compounds can be regarded as the most commonly used additives for improving the wear behavior.

As thickener or VI improver, an ethylene-propylene copolymer (Paratone 8002) was used. Although limited in their VI effect, ethylene-propylene copolymers are currently the most common VI improvers in car and truck engine oils due to their excellent thickening action.

The composition and test results of the test methods set out above are set forth in Table 1.

example 1

Comparative Example 1 was substantially repeated. However, to the motor oil formulation was added a polymer composition I according to the invention. Here, the thickening effect of Polymer Composition I with a reduced addition of Paratone 8002 was taken into account to maintain the viscosity adjustment of the engine oil formulation. The content of Paratone 8002 was thus reduced compared to the formulation of Comparative Example 1. This formulation according to the invention was also tested in the CEC-L-51-A-98 test. The composition and test results of the test methods set out above are set forth in Table 1.

Comparative Example 2

Comparative Example 1 was substantially repeated. However, a PAMA polymer of composition II was added to the motor oil formulation. With regard to the molecular weight and its oil-thickening effect, the polymer compositions I and II did not differ. For the preparation of the formulation according to Comparative Example 2, therefore, only the 3% by weight of the nitrogen-containing polymer of the polymer composition I was replaced by 3% by weight of the ethoxylate-containing polymer composition II. Such ethoxylated PAMA types of polymer composition II as well as polymer composition I have been described as dispersible VI improvers.

Table 1

It turns out that the nitrogen-containing polymers have outstanding wear-reducing effects, which can not be explained by the dispersing action and were not to be expected. N-containing polymers clearly differ from O-based (ethoxylated) representatives in terms of their advantageous wear protection function.

Claims

claims

1. Use of graft copolymers obtainable by a two-stage

In which, in a first stage, at least one graft base is obtained by free radical polymerization of a monomer composition A) containing 0 to 40% by weight, based on the weight of the monomer composition A), of one or more ethylenically unsaturated ester compounds of the formula (I)

wherein R is hydrogen or methyl, R ^{1 is} a linear or branched alkyl radical having 1 to 5 carbon atoms, R ² and R ^{3 are} independently hydrogen or a group of the formula -COOR ', wherein R' is hydrogen or an alkyl group having 1 to 5 carbon atoms 60 to 100% by weight, based on the weight of the monomer composition A), of one or more ethylenically unsaturated ester compounds of the formula (II)

wherein R is hydrogen or methyl, R ^{4 is} a linear or branched alkyl group having 6 to 40 carbon atoms, R ⁵ and R ^{6 are} independently hydrogen or a group of the formula -COOR ", where R" is hydrogen or an alkyl group having 6 to 40 carbon atoms means, have, and

0 to 40 wt .-%, based on the weight of

Monomer composition A), comprises comonomers, and in a second stage, a monomer composition B) comprising 20 to 100% by weight of at least one monomer having at least one nitrogen-containing group grafted onto the grafting base to reduce wear in lubricating oil compositions, characterized in that the graft copolymer is at most 200 ppm Sulfur and the ratio of the weight of the monomer composition A) to the weight of the monomer composition B) is in the range of 99.7: 0.3 to 80:20.

2. Use according to claim 1, characterized in that the grafting yield is greater than or equal to (x ^* 10 ^"5 mol / g + 35)%, where x is the GPC weight average molecular weight of the grafting base.

3. Use according to claim 1 or 2, characterized in that the graft base has a weight average molecular weight in the range of 5000 to 200,000 g / mol.

4. according to any one of the preceding claims, characterized in that the graft has a measured in chloroform at 25 ° C specific viscosity η _{sp / c} between 4 and 40 ml / g.

5. Use according to one of the preceding claims, characterized in that a measured in chloroform at 25 ° C specific viscosity η _S p _{/ c} between 5 and 50 ml / g.

6. Use according to one of the preceding claims, characterized in that the ratio of the specific viscosity of the graft copolymer to the specific viscosity of the graft base in the range of 1, 01: 1 to 1, 30: 1.

Use according to any one of the preceding claims, characterized in that the graft copolymer has a weight average molecular weight in the range from 5100 to 250,000.

8. Use according to one of the preceding claims, characterized in that the ratio of the weight-average molecular weight of the graft copolymer to the weight-average molecular weight of the graft base is in the range of 1:01: 1 to 5: 1.

9. Use according to one of the preceding claims, characterized in that the polymerization temperature in step 2 is greater than the polymerization temperature in step 1.

10. Use according to one of the preceding claims, characterized in that the polymerization temperature in step 1 in the range of 70 ⁰ C to 120 ⁰ C.

11. Use according to one of the preceding claims, characterized in that the polymerization temperature in step 2 is in the range of 110 ⁰ C to 140 ⁰ C.

12. Use according to any one of the preceding claims, characterized in that the monomer with at least one nitrogen-containing group is a compound of formula (III)

wherein R ⁷ , R ⁸ and R ⁹ independently of one another may be hydrogen or an alkyl group having 1 to 5 carbon atoms and R ^{10 is} a group containing 1 to 100 carbon atoms and having at least one nitrogen atom.

13. Use according to claim 11, characterized in that at least one monomer having at least one nitrogen-containing group is selected from the group consisting of aminoalkyl (meth) acrylates and aminoalkyl (meth) acrylatamides, such as N- (3-dimethylaminopropyl) methacrylamide, dimethylaminoethyl methacrylate Dimethylaminopropyl methacrylate, 3-diethylaminopentyl methacrylate,

3-Dibutylaminohexadecyl (meth) acrylate; heterocyclic (meth) acrylates, such as 2- (1-imidazolyl) ethyl (meth) acrylate, N-morpholinoethyl (meth) acrylate, in particular 2- (4-morpholinyl) ethyl (meth) acrylate and 1- (2-methacryloyloxyethyl) - 2-pyrrolidone; heterocyclic see vinyl compounds such as 2-vinylpyridine, 3-vinylpyridine, 2-methyl-5-vinylpyridine, 3-ethyl-4-vinylpyridine, 2,3-dimethyl-5-vinylpyridine, vinylpyrimidine, vinylpiperidine, 9-vinylcarbazole, 3-vinylcarbazole, 4-vinylcarbazole, 1-vinylimidazole, 2-methyl-1-vinylimidazole, N-vinylpyrrolidone, 2-vinylpyrrolidone, N-vinylpyrrolidine, 3-vinylpyrrolidine, N-vinylcaprolactam, N-vinylbutyrolactam, vinyloxazoles and hydrogenated vinyloxazoles.

14. Use according to claim 11 or 12, characterized in that 1 to 9 wt .-%, based on the weight of the graft of one or more compounds of formula (III) are grafted onto the graft.

15. Use according to one of the preceding claims, characterized in that the graft copolymer additionally has a viscosity index improving effect and / or a dispersing action and / or a detergent action and / or a pour point depressing effect.

16. Use according to one of the preceding claims, characterized in that the graft copolymer leads to a reduced energy consumption.

17. Use according to one of the preceding claims, characterized in that the lubricant mixture comprises friction modifiers and / or extreme pressure additives which are not graft copolymers according to claim 1.

Use according to any one of the preceding claims, characterized in that the lubricating oil composition contains 2-20% by weight of the graft copolymer

19. Use according to one of the preceding claims, characterized in that the monomer composition A) contains nitrogen-bearing monomers.

20. Use according to one of the preceding claims, characterized in that the use leads to a mean cam wear of at most 40 μm after 100 h measured according to CEC-L-51 -A-98.

21. Use according to one of the preceding claims, characterized in that the lubricating oil composition is used for lubricating internal combustion engines, transmissions, clutches or pumps.