CS212313B2 - Method of preparation of the polymere suitable as admixture in the lubricating oil or hydrogenous motor fuel - Google Patents

Abstract

The invention relates to the preparation of a graft a copolymer suitable as a lubricant additive oil or motor fuel based hydrocarbons. According to the invention, the procedure is followed so that it blends perfectly oil-soluble substantially linear, substantially saturated a rubbery ethylene-propylene polymer of main chains, grafted monomeric a system comprising maleic acid, maleic anhydride and at least one other monomer selected from the group consisting of 1-olefins, N-vinylpyrrolidone, alkylmethacrylates, alkyl acrylates, styrene and diisobutylene and radical initiator, with temperature during mixing in the presence of initiator is lower than the initiator decomposition temperature and then the temperature of the mixture increases to the decomposition temperature initiator or higher and then performs a subsequent reaction of the monomer system with a polyamine compound containing one primary or secondary amino group.

Description

The invention relates to a process for the preparation of a graft copolymer suitable as an additive in a lubricating oil or a hydrocarbon motor fuel. The graft copolymer prepared according to the invention has a multifunctional character. In particular, the invention is directed to the preparation of graft copolymers in which the grafted monomer units are derived from a monomer system comprising maleic acid or its anhydride and one or more other monomers that are copolymerizable with maleic acid or its anhydride.

Sludge in internal combustion engines is produced by oxidative degradation of lubricating oils and partial oxidation of motor fuels and by the by-products of combustion of motor fuels. The partially oxidized by-products of the combustion of motor fuels contain reactive intermediates, such as aldehydes, acids and hydroxy acids, which undergo complex condensation reactions to form insoluble resinous substances referred to as sludge and lacquer deposits. If these components are not dispersed relatively soon after formation, they fall out of the lubricant and settle, causing clogging of the filter and binding of moving parts of the engine.

In the past, lubricating oils and hydrocarbon motor fuels have been mixed with several additives to give them different properties, such as temperature-dependent viscosity improvement (viscosity index VI improvement), freezing point reduction, oxidation inhibiting properties, anti-corrosion properties and detergent properties. However, the addition of several additives greatly increases the cost of lubricating oil or motor fuel and causes problems with the compatibility of the additives and the possibility of their interactions. The graft copolymer additives of the present invention combine several of the above properties in a single substance and therefore represent a significant improvement over the additive mixtures.

The grafting of polar monomers onto polyolefin backbones to form additives for lubricating oils and motor fuels is known, for example, from U.S. Patent No. 3,404,091. The use of maleic anhydride as grafting monomer is also known from U.S. Patent Nos. 3,687,849 and 3,687,905. However, the products obtained by these processes have various drawbacks in their properties and / or are too expensive. This is mainly due to the insufficient amount of maleic acid or its anhydride being introduced into the graft copolymer and / or to the fact that the products contain too high amounts of by-products which are of little or no utility, such as homopolymers. Maleic acid or its anhydride is particularly desirable as graft monomers because they are relatively inexpensive and, since theoretically, represent an economical means of introducing nitrogen compounds with dispersing properties into polymers by reacting these nitrogen compounds with the carboxy groups of maleic acid or its anhydride. In practice, however, maleic acid or its anhydride polymerizes only to a minor extent during grafting. Therefore, by means of these compounds, it is not possible to introduce into the polymer such an amount of carboxy groups that would allow the incorporation of significant amounts of nitrogenous compounds having dispersing properties into the polymer by reacting carboxy groups with these nitrogenous compounds. The graft copolymers of the invention are prepared by a process which introduces the maximum amount of maleic acid or its anhydride into the polymer while minimizing by-product formation.

The graft copolymers of the invention combine the effective thickening properties that are characteristic of viscosity index improving polyolefin additives with the dispersing properties typical of nitrogen-containing substances. In the preparation thereof, a monomer system comprising maleic acid or its anhydride and at least one other (other) monomer which is maleic acid or its anhydride copolymerizable addition polymerase are used for grafting and the grafted monomer system is subsequently reacted with polyamine. The copolymerizable monomers are selected with respect to their reactivity with maleic acid or its anhydride so that more maleic acid or its anhydride can be introduced into the polymer than would be introduced in the absence of these comonomers.

The graft copolymers of the invention are effectively produced by forming a perfect blend of the backbone polymer, the copolymerizable monomer system, and the free radical initiator, while maintaining the temperature of the mixture at least as long as the initiator disperses uniformly below the decomposition temperature of the initiator. Then the temperature is raised to a temperature at which the initiator decomposes or to a higher temperature, preferably with continued stirring of the reaction mixture to form the graft copolymer and the resulting graft copolymer is subjected to an additional reaction with the polyamine. This process produces little or no by-products of loss-by-products.

The backbone polymer, i.e. the grafting substrate, preferably has a relatively high molecular weight corresponding to a mean viscosity molecular weight of about 100,000 to 200,000. In contrast to previous practice, the backbone polymer does not degrade prior to grafting. The molecular weight of the resulting graft copolymers is reduced by homogenization or other degradation techniques to achieve the desired balance of thickening properties, viscosity index improving properties, shear stability, detergent properties, and other additive properties in lubricating oils or motor fuels.

The graft copolymers of the present invention have the substantial advantage of having low manufacturing costs compared to the known nitrogen additives improving the viscosity index and having dispersing properties. In addition, in many cases the graft copolymers of the invention have substantially the same efficacy as the known nitrogen-containing graft copolymers, but at lower concentrations, which further increases their economic advantage.

Any substantially linear, substantially saturated, rubbery olefinic hydrocarbon polymer that is oil soluble before or after grafting the copolymerized monomers may be used as the graft substrate which forms the polymer backbones. Substantially saturated means that the polymer contains less than 4 and preferably less than 2 mol% of olefinically unsaturated double bonds. Polymers containing multiple olefinically unsaturated double bonds are too volatile to oxidation when used in lubricating oils. Suitable backbone polymers are ethylene / propylene copolymers, ethylene / propylene / diene terpolymers, hydrogenated styrene-butadiene copolymers, styrene / isoprene polymers and atactic polypropylene. Examples of backbone polymers to which oil solubility is imparted or grafted include low density polyethylene, and the like. Backbone polymers may have a molecular weight in a wide range, for example of the order of about 10,000 to 200,000 (viscosity mean molecular weight). The graft copolymerization generally increases the molecular weight up to about 200,000 to 400,000, and sometimes 500,000 or more. Typically, the molecular weight is increased to about 200,000 to 400,000 (viscosity mean molecular weight).

The choice of molecular weight of the backbone polymer and the extent to which the molecular weight is increased during the graft copolymerization depends primarily on the handling properties of the starting polymer and the desired shear strength of the resulting product. Low molecular weight backbone starting polymers, which prevent too much molecular weight increase during graft copolymerization, provide graft copolymer products with greater shear resistance. Such products therefore require, little or no additional degradation, which is carried out in order to reduce the molecular weight to a level providing good shear resistance. However, the lower molecular weight starting polymer substrates for grafting are more difficult to handle, since they are semi-liquid substances which exhibit cold flux at ambient temperature (about 20 ° C) and are often difficult or uneconomical to control the molecular weight during graft copolymerization. Thus, while the need to degrade the graft copolymer product can be avoided using low molecular weight starting polymers, difficulties in handling and processing such starting polymers tend to devalue this advantage. As a result, the backbone starting polymers with a somewhat higher molecular weight, i.e., a mean viscosity molecular weight of at least about 100,000, are preferably used, and the above problems can be avoided. The molecular weight of the polymer substrate naturally varies depending on the type of backbone polymers.

Ethylene / propylene (EP) copolymers can have a wide range of ethylene / propylene / propylene ratio. Above about 80 mole% ethylene, the copolymers are partially crystalline and thereby lose oil solubility and are not suitable as substrates for the purposes of the invention. More useful ethylene / propylene substrates comprise about 50 to about 70 mole% ethylene, have a mean viscosity molecular weight of from about 10,000 to about 200,000, and a fflw / Hn ratio of less than 4, where flw is the weight average molecular weight and Sn is the number average molecular weight. mass. Products with a lower propylene content, higher molecular weight and a broader molecular weight distribution can be used, but as mentioned, such copolymers result in graft products which are usually less effective as additives to improve the viscosity index. With regard to Mooney viscosity (ASTM test D-, 646, ML 1 + 8 at, 25 ° C), the ethylene-propylene substrates should have a value of about 20 to 40, preferably about 28, 14 to prevent cold flow. Above 50 the mixture becomes too viscous for proper mixing.

The diene-modified ethylene / propylene terpolymers contain a small amount (preferably less than 10%) of an unconjugated dlen such as 1,4-hexadiene, dicyclopentadiene or ethylidennorbornene. The maximum ethylene content is given by solubility (crystal formation); a content of 45 to 55 mol% of ethylene is preferred. The mean viscosity molecular weight range of the preferred products is about 10,000 to 200,000 and the Hw / fln ratio is less than 8. Even in this case, substrates whose properties do not fall within these ranges may be used, but this will result in sacrificing certain properties of the resulting product, as a viscosity index improver.

Preferred hydrogenated styrene-butadiene copolymers are irregular copolymers containing from about 30 to 55% by weight of butadiene having a viscosity average molecular weight of from about 25,000 to about 25,000. The hydrogenation is conducted to hydrogenate more than 95% of olefinically unsaturated bonds, but less than 5% of aromatic unsaturated bonds.

In the case of substrates composed of hydrogenated styrene-isoprene copolymers, block copolymers are preferably, but not exclusively, used. The polymers may contain 2 or more blocks. Styrene blocks typically have a molecular weight of about 5,000 to about 50,000 and their aromatic groups are at least about 50% hydrogenated, and isoprene blocks typically have a molecular weight of about 0,000 to about 1,000,000 and their olefinic bonds are also hydrogenated from at least about 50%. It is also possible to use irregular copolymers having similar compositions with respect to units derived from styrene and butadiene.

Amorphous polypropylene having a viscosity average molecular weight of about 10,000 to about 200,000 may also be used as a graft substrate. The entire class of these substrates results in additives with usually good dispersing properties, but the resulting graft copolymers usually have somewhat inferior properties as viscosity index improvers. .

All of the above polymeric substrates are defined to provide graft copolymers which are both excellent dispersants and good viscosity index improvers. Polyolefin substrates whose properties do not fall within the above ranges may also be used, but provide products that are good dispersants but have somewhat inferior viscosity index improvement properties.

Suitable monomers copolymerizable with maleic acid or its anhydride (preferably maleic anhydride) are any alpha, beta-monoethylenically unsaturated monomers which are sufficiently soluble in the reaction medium and reactive with maleic acid or its anhydride to be able to be grafted into the polymer product. to introduce substantially higher amounts of maleic acid or its anhydride than can be introduced using maleic acid alone or maleic anhydride alone. Suitable monomers are acrylic and methacrylic acid esters, amides and nitriles and other monomers that do not contain free acid groups. Representative examples of these groups are methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclohexyl, 2-ethylhexyl and acrylic or methacrylic acid isodecyl esters. Other suitable monomers are styrene, alpha-methylstyrene, C 1 -C 4 -alkyl ring and alkoxy-substituted styrenes such as p-methylstyrene, p-sec-butylstyrene, p-methoxystyrene and () 4-0.2 alpha-olefins such as ^e isobutylene and the like. other types of monomers include vinyl esters such as vinyl acetate, propionate and butyrate, vinyl ketones such as methyl and ethyl vinyl ketone; and other vinyl and vinylidene monomers such as vinyl chloride and vinylidene chloride. Any mixtures of two or more of these comonomers may be used. Comonomers containing more than one polymerizable double bond and / or functional groups that can cause crosslinking or gelation, such as hydroxy and primary or secondary amino groups, are not suitable. Conjugated diolefins such as butadiene may be used in smaller amounts because these monomers have a lower tendency to crosslink than unconjugated diolefins. Although monomers may contain up to about 40 carbon atoms, monomers containing up to about 0 carbon atoms are preferred. The higher content of carbon atoms in the molecule increases weight and cost and has no particular advantages either in terms of the ease of copolymerization with maleic acid or its anhydride or in the resulting properties of the product as an additive for improving the viscosity index and dispersing additive.

Extensive studies have been carried out in the past on the reactivity of maleic anhydride with other monomers, and the inactivation ratios (copolymerization parameters) for each system are also reported. This allows the chemist to easily select the monomers and their ratios so that the introduction of maleic anhydride into the graft copolymers of the invention is optimal. Some monomers ideally alternate with maleic anhydride in each of the grafted chains, some monomers form blocks with maleic anhydride in the grafted chains, and some form irregular copolymer chains. Examples of such studies include Flory: Principles of Polymer Chemistry, Cornell University Press, 1953, pp. 178-199, in particular Tables XX and XXII and Tiredrup and Immergut: Polymer Handbook, Second Edition 1975, John Wiley and Sons, Inc., pp. 11-105, 11-227-229.

The monomer ratios depend on the reactivity of the selected monomers. Larger amounts of comonomers are needed when selecting a monomer that is more prone to homopolymerization than to copolymerization with maleic anhydride. Typically, the ratio of maleic anhydride to comonomers to each other is in the range of about 1: 4 to 4: 1, preferably in the range of about 1: 2 to 2: 1. Sufficient maleic anhydride should be present in the monomer system to provide about 1 to 10% by weight of maleic anhydride, based on the weight of the product, in the graft copolymer product. The preferred amount of maleic anhydride is 2 to 6% by weight.

In addition to forming a perfect mixture of reactants with a free-radical initiator at a temperature below the decomposition temperature of the initiator and then increasing the reaction temperature to above the decomposition temperature of the initiator, graft copolymers are prepared by conventional radical copolymerization procedures. As a typical example of such a process when ethylene / propylene copolymers are used as the polymeric substrate that forms the backbone, the following process may be mentioned. The backbone polymer is dissolved in a suitable inert solvent such as a halogenated aromatic hydrocarbon at a temperature of about 80-150 ° C to a solution having a concentration of about 20-30% by weight. Dissolution of the polymer is aided by suitable mixing, such as magnetic or mechanical mixing. The grafted monomers are then mixed with the solution, usually at a lower temperature, such as at 80 ° C, preferably with stirring of the reaction mixture. The graft monomers are added to the mixture in a total amount of about 2 to 30% by weight, based on the ethylene / propylene copolymer, preferably in an amount of about 5 to 20% by weight. If necessary, the temperature of the mixtures is again lowered to a temperature below the decomposition temperature of the initiator, and then the initiator is added and evenly distributed in solution. The temperature, stirring, order, and rate of addition are carefully selected to minimize homopolymerization and graft copolymerization at this time. The initiator is added in an amount of from about 0.5 to 2% by weight based on the ethylene / propylene copolymer. After uniformly dispersing the initiator in the mixture, the temperature is gradually raised to or above the decomposition temperature of the initiator. In the case of tert-butyl peroxybenzoate, this temperature is about 120-140 ° C. This temperature is maintained until the reaction is substantially complete. A reaction time of about 1 to 2 hours is usually sufficient. The reaction product typically contains about 2 to 25% by weight, preferably about 4 to 20% by weight of grafted monomers.

AND"

Any free radical source capable of abstracting hydrogen can be used as the free radical initiator. Examples are alkylperoxoesters, alkylperoxides, alkylhydroperoxides, diaeyl peroxides, etc. The preferred initiator is tert-butyl peroxybenzoate, other initiators such as tert-butyl peroxy octoate, di-tert-butyl peroxide, tert-butyl hydroperoxide, benzene hydroperoxide, benzene hydroperoxide and the like can be used.

The temperature at which the grafting is carried out may be from about 80 to 150 ° C. However, the temperature chosen naturally depends on the decomposition temperature of the initiator © on the polymer substrate and the grafted monomers. As a result, it may be possible to perform grafting at a temperature as low as 60 ° C and as high as about 250 ° C.

As already mentioned, a perfect blend of polymer substrate, graft monomers and initiator is prepared according to the invention prior to the grafting reaction, and the temperature is maintained below the decomposition temperature of the initiator, at least during addition and mixing of the initiator with the solution. This avoids the formation of free radicals until the reactants are completely and homogeneously mixed. This process eliminates or substantially reduces the formation of unwanted by-products, such as a homopolymer, and increases the grafting of the oxygen-containing polar polymer.

During the grafting reaction, any solvent medium can be used to prepare the graft copolymer provided that the medium is substantially inert to the reactants, i.e., the medium does not cause or cause only a small chain transfer. Halogenated aromatic hydrocarbons such as chlorobenzene are preferred. or dichlorobenzene, especially dichlorobenzene. However, in some cases aliphatic or aromatic hydrocarbons, including mineral oil, are suitable.

While the process of the present invention has been explained so far that the copolymerizable reactants are dissolved in a solvent, but when the polymer forming the substrate for grafting and its mixture with the grafted monomers has a sufficiently low melt viscosity for homogeneous mixing and grafting at the reaction temperature, even without solvent. The order and rate of addition of the individual reactants and initiator are not critical as long as the temperature is controlled as described above.

The carboxyl groups introduced into the grafted chains via maleic acid or maleic anhydride are subsequently reacted with a non-polymerizable polyamine to form a structure, which for simplicity is referred to as a carboxypolyamine adduct. The polyamine is added in an amount sufficient to react substantially all of the carboxy groups. This reaction is often referred to as neutralization and its product is amide, imide, amidine and other structures. All of these structures fall within the term carboxypolyamine adduct. The polyamine may essentially contain only one amino group which is reactive to the carboxyl groups of the grafted maleic acid or maleic anhydride. Additional reactive amino groups tend to cause interfering reactions. A reactive amino group is a primary or secondary amino group. Any remaining nitrogen in the polyamine should be substantially unreactive to the grafted maleic acid or maleic anhydride.

. Polyamines can be characterized as aliphatic, cycloaliphetic, aromatic or heterocyclic and can be mixed in nature. Polyamines may carry other functional groups, such as hydroxyl groups, provided that these groups do not cause interfering reactions. Examples of suitable polyamines include:

dimethylaminoethylamine, dibutylaminoethylamine,

3-dimethylamino-1-propylamine,

4-methylethylamino-1-butylamine, pyridyl thylamine,

N-morpholinoethylamine, tetrehydropyridylethylamine, bis- (dimethylamino) propylamine, bis- (diethylamino) ethylamine,

N, N-dimethyl-p-phenylenediamine, piperidylethylamine,

1-aminoethylpyrazole,

1- (methylamino) pyrazoline

1-methyl-4-aminoctylpyrazole,

1-aminobutylimidazole,

4-aminoethylthiazole,

2-aminoethyltriazine, dimethylcarbamoylpropylamine,

N-methyl-N-aminopropylacetamide,

N-aminoethylsuccinimide,

N-methylaminomaleinimide,

N-aminobutyl-alpha-chlorosuccinimide,

3-aminoethyluracil,

2-aminoethylpyridine, o-aminoethyl-N, N-dimethylbenzenesulfamide,

N-aminoe thylpheno thiazine,

N-aminoethylacetamide,

1-aminophenyl-2-methylimidazoline,

N-methyl-N-aminoethyl-S-ethyldithiocarbamate,

N-phenylmoquin,

N- (3-aminopropyl) morpholine

4-aminomethylpyridine,

N- (3-aminopropyl) -2-pyrrolidinone

N- (3-aminopropyl) -N'-methylpiperazine,

1- (2-Aminoethyl) -2-methyl-2-imidazoline

N- (5-aminopentyl) -2,5-dimethylpyrrole,

2-aminothiazole a

2-aminobenzothiazole.

Thus, the polyamides preferably contain one primary or secondary amino group and at least one tertiary amino group, such as a heterocyclic amino group. Examples of the latter include aminoalkyl-substituted piperidines, morpholines, piperazines, pyridines, pyrrolidines, pyrroles, benzopyrroles, quinolines, indoles and the like. Also suitable are polyamines containing non-reactive nitrogen in other groups such as substituted primary or secondary amines in which the substituent is derived from pyrrolidones, caprolactams, oxazolidones, oxazoles, thiazoles, pyrazoles, pyrazolines, imidazoles, imidezolines, thiazines, oxazines, diazines in which the substituent is oxycarbamoyl, thiocarbamoyl or wherein the substituent is derived from uracil, uracil, sulfoanone, uracil, uracil, , phosphoramides, phenothiazines, amidines and the like. The polyamines may contain up to about 6 nitrogen atoms, preferably 2 to 4 nitrogen atoms and 4 to about 30 carbon atoms, preferably 4 to about 12 carbon atoms.

The reaction of the graft copolymer with the polyamine is conveniently carried out in a solvent reaction medium containing the graft copolymer. If desired, the graft copolymer may be separated and redissolved, or the reaction product may be concentrated prior to the addition of the poylamine. The reaction is carried out at a temperature of about 80 ° C, preferably about 120 to 300 ° C, but outside the temperature at which the graft copolymer decomposes. Typically, the temperature range is from about 150 to 250 ° C. In order to complete the reaction, it is expedient to use polyamine in excess of the stoichiometric amount, on the order of about 1 to 10% of the excess. The reaction is substantially complete when titration indicates that no more than about 2% of the carboxy groups remain in the graft copolymer.

When polymer additives for improving the viscosity index are exposed to strong mechanical stresses in the equipment in which they are used, polymer degradation can occur, thereby reducing the beneficial effect these additives have on the temperature / temperature dependence of the viscosity of the lubricant or motor fuel. Polymers that resist this tendency to mechanical degradation in service are referred to as shear-stable polymers. The ability of additives to improve the viscosity index to resist mechanical degradation during use depends on a number of factors, one of which is the molecular weight. A very high molecular weight polymer initially excellently regulates the dependence of the viscosity of a lubricant or fuel on temperature, but it degrades very strongly during operation, losing much or almost all of its effect.

The graft copolymers produced by the process of the invention may have an excessively high molecular weight for their effective use, although they are good additives for improving the viscosity index. However, they have poor stability to shear. As already mentioned, this is partly due to the manufacturing technology introduced in the rubber industry, in particular in the production of ethylene-propylene-based copolymers and terpolymers. Indeed, these polymers are usually produced with very high molecular weights so that the products are relatively hard solids that are easy to handle and easy to transport. When these rubbers are produced with a molecular weight suitable for use as viscosity index improving additives, the polymers obtained are in the nature of sticky solids which exhibit creep even at ambient temperatures. Although the technology for treating such molecular weight products is known, such as the technology described in the oxidative degradation process of U.S. Patent Nos. 3,404,091 and 3,687,849, however, such polymers require special handling. Also, the processing of such polymers is slower, resulting in increased costs. Thus, when conventional ethylene / propylene rubbers are used in the process of the invention, the products have too high a molecular weight to have an acceptable shear resistance.

Another factor that adversely affects shear resistance is due to one aspect of the process of the invention. During the grafting, the reaction mixture became very thick, and when tested on the graft copolymer, it was found that the shear resistance of the product deteriorated during the grafting. This is probably because crosslinking may be part of the reaction. Although crosslinking can be eliminated, products whose crosslinking has been suppressed usually have inferior dispersing properties. Accordingly, in the process according to the invention, in order to achieve optimum dispersing properties, a certain compromise has to be made regarding shear stability.

There are simple means to reduce the molecular weight to a value in the desired range where shear stability is good. It is only necessary to subject the grafting product to mechanical or thermal degradation in order to set the molecular weight in the preferred range. While the graft copolymerization products have a viscosity average molecular weight of up to about 500,000 or more, it is estimated that the desired range for the resulting additive to be useful as a dispersant and as a viscosity index enhancer is about 30,000 to 80,000.

Any suitable degradation method, such as degradation in a gear pump or extruder, may be used, but homogenization is preferred. During homogenization, the polymer is extruded under high pressure through a device comprising chokes and narrow nozzles of various embodiments. Such an apparatus can create a degree of shear of about 5000 ^- 'and preferably about 10 000 to 1 000 000 s ^-'. Commercially available devices such as those manufactured by the Manton-Gaulin Manufaoturing Company or modifications thereof may be used. To achieve the necessary shear stress, such a device can operate at a pressure of up to about 500 psig. Homogenization can be carried out either batchwise or continuously depending on the degree of degradation desired.

An additional advantage of homogenization is that the thus treated products of the invention are even more effective thickeners than commercially available ethylene / propylene copolymers which do not

2,23,3 dispersing properties. Thus, the products according to the invention, when homogenized, appear to have not only better dispersing properties but also an excellent balance of thickening and shear stability.

The products of the invention can be used in a wide variety of fuels and lubricants. They are of prime utility for lubricants where both their excellent dispersing ability and their effect on temperature-dependent viscosity control are valuable. Suitable base lubricants are oils of both mineral (petroleum) and synthetic origin. Oils can have different viscosities, from spindle oils to engine oils and gear oils. Suitable synthetic liquids include esters such as dialkyl adipate, dialkyl sebacate, or dialkyl azlate, trimethylolpropane triesters, pentaerythritol tetraesters, polyalkylene glycol esters, phosphoric acid esters, or poly-alpha-olefin or alkylbenzene synthetic hydrocarbons. Typical applications of such lubricants include hydraulic fluids, automatic transmission fluids, four-stroke engine lubricating oils, transmission oils and greases.

The products of the invention may be used in lubricants in an amount of from about 0.1 to 5.0, preferably from about 0.3 to 2.0, but typically from about 0.6 to 1.5% by weight. Since the products of the present invention are rubbery solids, they can conveniently be formulated into viscous concentrates containing about 7-5.5% solids in oil. The consumer can then use the concentrate in an amount corresponding to the content of the polymer component so that the content of the component in the lubricant is within the above range.

Lubricants containing the products of the invention may also contain other additives to further enhance dispersing properties and temperature-dependent viscosity control, to lower melting point, to impart detergent properties and high temperatures, corrosion inhibition, anti-wear additives, antioxidants, additives to impart high resistance pressures, friction reducing agents, antifoams or dyes. Accordingly, succinimides or esters based on polybutene, phosphosulfurized polybutenes, polyacrylates or polymethacrylates, polyisobutylene, ethylene / propylene copolymers or terpolymers, hydrogenated styrene-butadiene copolymers or styrene-dimethylene copolymers or copolymers or copolymers, copolymers or copolymers may be used together with the products according to the invention. with methacrylates, styrene polyesters, ethylene-vinyl acetate copolymers or oligomers, diacyl fumarate polymers or copolymers, esterified copolymers or oligomers of styrene and maleic anhydride, hydrocarbon wax condensates with Friedel-Crafts type naphthalene, alkali metal sulphonates, sulfonates of phenols, alkaline earths, dialkyldithiophosphates or diaryldithiophosphates of zinc or other metals, dithiocarbamates of zinc, cadmium, lead, molybdenum or other other metals, sulfurized or phosphosulfurized esters or erpenes, sterically hindered phenols, phenothiazine or alkylated phenothiazines, naphthylamines, phenylenediamines, dibenzyldisulfide, sulfurized diisobutylene or triisobutylene, trialkyl or triarylphosphites, tricresylphosphates or tricresylphosphates or tricresylphosphates.

When used in hydrocarbon motor fuels where their excellent dispersing properties are utilized, the products of the invention are generally added in lower amounts, typically in an amount of about 0.001 to 0.1% by weight. Both gasoline and diesel engine fuels can be used as fuels, and these fuels can also contain other additives such as antioxidants, metal deactivators, stabilizers, anticorrosive additives, injector detergents, seed suppressant additives and other carburetor additives. All parts and percentages given in the description and examples are parts and percentages by weight unless otherwise indicated. The detergency test is based on the following procedures.

Test procedures for the determination of dispersing properties

A. Asphalt test

This assay, which detects the dispersing activity of any polymer, is based on the polymer's ability to disperse asphaltenes in a typical mineral oil. The asphaltenes are obtained by oxidizing the naphthenic oil with air with traces of iron salts, such as ferric naphthenate, as a catalyst. Suitably, the oxidation is carried out at 175 DEG C. for about 72 hours by bubbling an air stream through the naphthenic oil to form a sludge which is separated by centrifugation. The sludge was freed of oil (pentane extraction) and then taken up in chloroform. The concentration of the resulting solution is adjusted to 2% (w / v).

The polymer whose dispersing efficiency is tested is dissolved in a standard oil, such as a solvent-extracted neutral oil 100. Mixtures containing from about 2% to 0.01% or less polymer in oil are prepared.

A 10 ml sample of this mixture is treated with 2 ml of a standard solution of asphaltenes in chloroform. The sample and reagent are mixed thoroughly in a test tube and placed in an oven and forced to set at 90 or 150 ° C. The tube is left in the oven for 2 hours to strip off the volatiles, then allowed to cool and the appearance of the sample is observed.

If the polymer has dispersing properties, the oil is clear, although colored. Experience has shown that if the polymer does not exhibit dispersing properties at a concentration below about 2% in this test, it is unable to improve the cleanliness of the engine parts in actual engine tests.

B. Sequence V-C Test

This test is an engine test that evaluates oil for four-stroke engine lubrication during engine operation at a combination of low to medium temperatures for sludge and paint deposits. The test also shows whether my oil's ability to maintain cleanliness and good functioning of the crankcase ventilation (PCV) valves. In short, the test can be described as follows:

The test uses a test engine and a kit supplied by Ford Motor Company under the name 302 C.I.D. V-C Sequence V-C Oil Test Engine and Parts Kit. The test engine shall be completely disassembled and assembled as described. It is then installed on a bench for bench testing with a dynamometer equipped with suitable accessories to control speed, load and other conditions. The engine operates using proven MS-08 fuel in three stages. During the first stage, the engine operates for 120 minutes at high power and at low oil and water temperatures while using a lean (air / fuel ratio). During the second stage, the engine operates for an additional 75 minutes at higher oil and water temperatures. During the third stage, the engine operates for 45 minutes at low speed and low oil and water temperatures, using a rich mixture. This four-hour cycle is repeated four times each day until a total of 48 cycles (192 hours of engine operation) are performed.

At the end of the test, the engine is completely disassembled and the degree of wear, the amount of sludge and paint deposits, and the amount of deposits in the valves are determined. In addition, clogging of the crankcase valve, lubrication rings and oil strainer is detected. The test evaluates the dispersing properties of the sludge lubricant in low and medium temperature operation. The operation of the test engine shall be under the conditions described in ASTi. 315 K.

Example 1

A. Preparation of graft copolymer

A sample of ethylene / propylene copolymer 50/50 (Epoar 506, Goodrich Chemical Co.) weighing 350 g is placed in a 5 liter flask containing 1050 g of o-dichlorobenzene. Mon,

The 2.2313 nitrogen purge is heated to about 50 ° C and mixed with a Type C metal stirrer until a homogeneous solution is formed. A nitrogen atmosphere is maintained over the reaction mixture during this step and throughout the reaction cycle. After 2 hours a homogeneous solution was obtained. The polymer flow was then cooled to 80 ° C and 35.0 g of methyl methacrylate (UMA) and 17.5 g of maleic anhydride (MAH) were added. These monomers are thoroughly mixed with the solution for 35 minutes. A mixture of 1.75 g of tert-butyl peroxybenzoate as initiator in 25 g of o-dichlorobenzene is then added. The temperature was then raised to warm the reaction mixture to 140 ° C over 45 minutes. The grafting starts at about 120 ° C, as evidenced by the increase in solution viscosity. The temperature of the solution was maintained at 40 ° C for 1 hour to complete the graft polymerization, and then the reaction mixture was diluted with 1500 g of oil (100 neutral viscosity oil). Disconnect the nitrogen inlet and connect a vacuum distillation apparatus consisting of a condenser and a receiver. Volatile components were stripped from the solution at 40 ° C at 1 mm Hg. The total removal time is about 3 hours. The presence of both methyl methacrylate and maleic anhydride in the resulting polymer product was confirmed by infrared analysis. Titration of the polymer solution shows that 89.1% of the maleic anhydride employed was grafted. Analysis of the distillate obtained from stripping showed that 88.5% of methyl methacrylate was grafted. The graft olefin polymer contains 8.9% methyl methacrylate and 4.5% maleic anhydride.

B. Modification of graft copolymer by subsequent reaction

500 g of the 8.4% polymer solution produced in paragraph A are placed in a 51 liter flask equipped with a thermometer, stirrer and nitrogen inlet. The solution was heated to 140 ° C under nitrogen and 21.6 g of N- (3-aminopropyl) morpholine (NAPM) was added. Within 15 minutes, the viscosity of the solution increases considerably, after about 2 hours the viscosity of the solution returns to approximately its original level, probably when the amic acid is converted to the imide. The solution was further heated with stirring for 16 hours and then the nitrogen inlet was disconnected and replaced with a condenser and receiver. Any unreacted N- (3-aminopropyl) morpholine was removed by vacuum distillation for about 1 hour at about 150 ° C and a pressure of 267 ^Pa. After stripping off the N- (3-aminopropyl) morpholine, the solution is homogenized at a pressure of 1.0 MPa in a triple pump capable of exerting a pressure of 206 MPa, Kobe type 3, in order to reduce the molecular weight. Analysis of the resulting product showed a nitrogen content (Kjelchahl) of 0.76%, indicating that the content of N- (3-aminopropyldmorpholine, expressed as maleimide content, was 6.1%). No residual anhydride bands are present in the spectrum

Using the standard asphaltenes dispersion test described above, it was found that 0.0625 g of polymer product dispersed 0.4% of asphaltenes at 150 ° C.

An oil of SAE 10W / 40 classification is prepared by mixing 12.4% by weight of the resulting homogenized imide product concentrate, 1.5% by weight anti-abrasion additive based on zinc dialkyldithiophosphate and 2.0% by weight basic magnesium sulphate in an oil load consisting of solvent-refined lubricating oil. . Thus, the oil contains 1.04% copolymer product. When tested using the above-described V-C engine test, the following excellent values are found: sludge 9.0; lacquer 8.3; paint on piston housing 7.2 after 200 hours of operation.

Example 2

The procedure described in Example 1 was repeated except that 22.5 g of N, N-dimethylaminopropylamine (NN-NMAPA) was used in place of N- (3-aminopropyl) morpholine and that the polymer product prepared according to paragraph A was used in the form of of a 9.8% solution. Analysis of the final product revealed a nitrogen content (Kjeldahl) of 0.94%, indicating that the content of Ν, Ν-dimethylaminopropylamine, expressed as maleimide, was 6.1%. The infrared spectrum of the isolated polymer contains imide bands but no residual anhydride bands.

Using the standard asphaltenes dispersion test described above, it was found that 0.0625 g of polymer product dispersed 0.4% of asphaltenes at 150 ° C.

An SAE 10W / 40 oil is prepared by mixing 14.6% by weight of the final homogenized product (1.43% polymer in the final blend) 1.4% by weight anti-abrasion additive based on zinc dialkyldiophosphate and 2.0% by weight basic magnesium sulfate an oil base consisting of a solvent refined lubricating oil. When tested using the above-described V-C engine test, the following excellent values are found: sludge 9.6; lacquer 8.4; paint on the piston housing 7.9 after, 92 hours of operation.

Example 3

The procedure described in Example 1 was repeated except that 30.0 g of 4-aminomethylpyridine (AMP) was used in place of N- (3-aminopropylmorpholine) and that the polymer product prepared according to paragraph A was used in the form of a 12.3 An analytical Kjeldahl nitrogen determination of the resulting product revealed a nitrogen content of 0.82%, corresponding to a 4-aminomethylpyridine content, expressed as a maleimide content of 5.6%, and an infrared spectrum of the polymer confirms imide formation.

Using the standard asphaltenes dispersion test described above, 0.125 g of polymer product was found to disperse 0.4% of the asphaltenes at 150 ° C.

A SAE 10W / 40 oil is prepared by mixing 11.2% by weight of the resulting homogenized product (1.35% polymer in the resulting oil mixture), 1.5% by weight zinc dialkyldiophosphate anti-abrasion additive, and 2.0% by weight basic sulfate. magnesium in an oil base consisting of a solvent-refined lubricating oil. When tested using the V-C engine test described above, the following excellent values are found: sludge 9.7; lacquer 8,0; paint on piston housing 7.4 after 192 hours of operation.

Example 4

The procedure described in Part A of Example 1 was repeated except that 20.0 g of styrene was used instead of methyl methacrylate. The analysis shows that the graft copolymer contains 5.0% styrene and 4.5% maleic anhydride.

The graft copolymer thus obtained is reacted with N- (3-aminopropyl) morpholine essentially as described in Part B of Example 1. The resulting product contains about 6.0% of the imide product and exhibits dispersing properties according to the asphaltene test described above.

Examples 5 to 9

In principle, the procedure described in paragraph A of Example 1 is repeated except that 35.0 g of methyl acrylates are used as graft comonomer together with maleic anhydride instead of methyl methacrylate. The graft copolymer product is then subsequently reacted with the amines listed in Table I under substantially the same conditions as those set forth in Part B of Example 1 except that the amine-modified graft copolymer is not homogenized to reduce the molecular weight. (The dispersing properties do not depend on the improved shear stability achieved by homogenization.) The degree of dispersing properties in the asphaltene test described above is shown in Table I. All products modified by the subsequent reaction exhibit dispersing properties and also provide improved viscosity index when used in lubricating oils. Improving the viscosity index provides oils with the main polymer chain of these products.

Examples 10 to 16

The amines listed in Table I are reacted (Examples 10-16) with the product obtained as described in Part A of Example 1 under the conditions substantially described in Part B of Example 1, except that no homogenization is performed. Results of the asphaltenes dispersion test given

2123.3 in Table I show that the products have good dispersing properties in lubricating oils. The products also improve the viscosity index of oils, which is in particular the effect of the polymer backbone.

Table I

Example Amin Amine used for additional reaction Degree of dispersion of asphaltenes h 5 N, N-dimethylaminopropylamine 6 6 N- (2-aminoethyl) morpholine 5 7 N- (3-aminopropyl) morpholine 4 8 1- (2-Aminoethyl) -2-methyl-2-imidazoline 1 9 N- (5-aminopentyl) -2,5-dimethylpyrrole 1 , 0 N-phenylurea 1 11 N- (2-aminoethyl) morpholine 3 12 2- (2-Aminoethyl) pyridine 6 , 3 N- (3-Aminopropyl) -2-pyrrolidone 5 14 N- (3-aminopropyl) -N'-methylpiperazine 6 15 Dec 2-aminothiazole 3 , 6 2-aminobenzothiazole 3

* = The degree of dispersion of asphaltenes is determined according to the following table:

Table

Degree of dispersion of asphaltenes

Concentration of the additive to be used to obtain acceptable results

2,0

1.0

0.5

0.25

0.12

0.06

Example, 7

A graft copolymer containing, as a backbone polymer, an ethylene / propylene copolymer onto which a mixture of maleic anhydride and a mixture of olefins is grafted.

24.0 g of ethylene / propylene copolymer (Epcar 506) are placed in a 500 ml flask containing 73.8 g of o-dichlorobenzene. After purging with nitrogen, the contents of the flask are heated to about 110 ° C and mixed using a Type C stirrer to form a homogeneous solution. During this step and throughout the reaction, the mixture is maintained under a nitrogen atmosphere. When a homogeneous solution is formed, 3.92 g of maleic anhydride, 2.54 g of 1-tetradecene, 2.02 g of 1-hexadecene, 2.27 g of 1-octadecene and 2.52 g of 1-teticosene are added and the mixture is converted into solution by vigorous stirring for 30 minutes. 0.3046 g of t-butyl perbenzoate initiator in 2.2 g of o-dichlorobenzene are then added. The temperature which was maintained at -10 ° C during this addition was now increased to 35 ° C. After 1 hour at 135 ° C, the temperature was raised to 140 ° C and held at this temperature for 1 hour to complete the graft polymerization. Then the mixture is diluted with 276 g of oil (100 neutral viscosity oil). Disconnect the nitrogen inlet and connect a vacuum distillation apparatus consisting of a condenser and a receiver. Volatile components were stripped from the solution at 140 ° C at 1 mmHg. After stripping off the volatiles (about 1 hour), 1.30 g of Ν, Ν-dimethylaminopropylamine (N, N-DMAPA) was added to the flask. The viscosity of the solution increases substantially within 15 minutes. As shown in Example 1, the viscosity

Eventually the solution drops over time, probably because the amic acid is converted to the imide. After 1 hour, the solution was again vacuumed at 140 ° C at 1 mm Hg. After stripping off the volatiles, 6.0 g of n-butanol was added and the solution was stirred at 120-130 ° C for 2 hours. The solution was then re-evaporated at 150 ° C and 1 mm Hg until the volatiles had disappeared. According to the analysis, the resulting product contained 0.81% nitrogen (kjeldahlisation), indicating a content of 5.3% Ν, Ν-DMAPA, expressed as maleimide. Using the standard asphaltenes dispersion test described above, it was found that 0.0625 g of polymer product dispersed 0.4% of the asphaltenes at 150 ° C.

Example 18

A graft copolymer containing, as a backbone polymer, an ethylene / propylene copolymer to which a mixture of maleic anhydride and 1-octene is grafted

In principle, the procedure described in Example 17 is repeated except that 25.0 g of ethylene-propylene copolymers, 3.75 g of maleic anhydride, 73.0 g of o-DCB and 0.3169 g of tert-butyl peroxybenzoate are used. Instead of the olefinic mixture used in Example 17, 4.50 g of 1-octene is used.

After the grafting reaction was completed and after vacuum evaporation, as in Example 7, 3.0 g of Ν, Ν-DMAPA was added. After 1 hour, the solution was evaporated in vacuo at 155 ° C and 1 mm Hg until all volatiles were removed. Analysis showed a nitrogen content of the final product (by co-compression) of 0.73%, indicating a content of 4.8% Ν, Ν-DMAP expressed as maleimide. Using the standard asphaltenes dispersion test described above, it was found that 0.0313 g of polymer product dispersed 0.4% of the asphaltenes at 150 ° C.

Example 19

Graft copolymer containing ethylene / propylene copolymer as the backbone polymer onto which a mixture of maleic anhydride and N-vinylpyrrolidonone is grafted

In principle, the procedure described in Example 17 was repeated except that 25.0 g of ethylene-propylene copolymers, 2.50 g of maleic anhydride, 73.0 g of o-DCB and 0.3031 g of tert-butyl peroxybenzoate were used. Instead of the olefinic mixture used in Example 17, N-vinylpyrrolidinone (NVP) was used. Further processing of the reaction mixture utilized 3.0 g of Ν, Ν-DMAPA. Analysis showed a nitrogen content of 1.00% in the final product (kjeldahlislation), indicating a content of 4.8% Ν, Ν-DMAPA expressed as maleimide. Using the standard asphaltenes dispersion test described above, it was found that 0.0625 g of polymer product dispersed 0.4% of the asphaltenes at 150 ° C.

Example 20

Graft copolymer containing ethylene / propylene copolymer as the backbone polymer onto which a mixture of maleic anhydride and a mixture of methacrylates is grafted

In principle, the procedure described in Example 18 was repeated except that 1.00 g of maleic anhydride and 0.2827 g of tert-butyl peroxybenzoate were used. Instead of 1-octene, a mixture of 5.70 g of dodecyl pentadecyl methacrylate and 2.45 g of cetyleicosyl methacrylate is used. 1.1 g of r, Ν-DMAPA are used for further processing of the graft product. Analysis of the resulting products (two samples) revealed a Kjeldahl nitrogen content of 0.61 and 0.63 Si, indicating that the Ν, Ν-DMAPA content expressed as maleimide was 2.3%. Using the standard asphaltenes dispersion test described above, it was found that 0.0625 g of polymer product dispersed 0.4% of asphaltenes at 150 ° C.

Example 21 to 27

A graft copolymer containing, as a backbone polymer, an ethylene / propylene copolymer onto which a mixture of maleic anhydride and tetradecene is grafted

2,23,3

In principle, the procedure described in Example 8 was repeated except that 00 g of an ethylene-propylene copolymer, 10.0 g of maleic anhydride, 192 g of o-DCB and 1.3877 g of tert-butyl peroxybenzoate were used. After the vacuum stripping of the volatile components, the graft polymer is reacted with the amines listed in Table II as described in Example 18. The resulting products have a Kjeldahl (N ^) nitrogen content and a standard asphaltenes dispersion test as shown in Table II.

Table II

Example The amine used for the reaction ^N k Asphaltenes 2, 1- (beta-aminoethyl) -2-imidazolidone 1.56 7P 22nd N-3-aminopropylmorpholine 0.65 6P 23 4-Aminomethylpyridine 0.82 6P 24 amines derived from hydrogenated tallow 6P 25 Kemamine D-970 (Humko-Sheffield) - (hydrogenated tallow-derived diamine) 0.80 6P 26 Kemamine D-150 (Humko-Sheffield) - ^{G-20 G-22} '> ^R 3P ° pendiamin 0.50 6P 27 Mar: N, N-dimethylaminopropylamine 0.64 6P

Example 28

Graft copolymer containing ethylene / propylene copolymer as the backbone polymer onto which a mixture of maleic anhydride and diisobutylene is grafted

In principle, the procedure described in Example 19 was repeated except that 2.86 g of diisobutylene was used instead of NVP. Analysis showed that the final product contained 0.47% Kjeldahl nitrogen, indicating that the Ν, Ν-DMAPA content, expressed as maleimide, was 3.06%. Using the standard asphaltenes dispersion test described above, it was found that 0.0625 g of polymer product dispersed 0.4% asphaltenes at 50 ° C.

Example 29

Graft copolymer containing ethylene / propylene copolymer as a backbone polymer onto which a mixture of maleic anhydride and CEMA is grafted

In principle, the procedure described in Example 9 was repeated except that 5.00 g of cetylleonyl methacrylate (CEMA) was used in place of ok-octene and 1.87 g of 3-aminopropylmorpholine (3) was used instead of reakci, DM-DMAPA in an additional reaction. -AM). Analysis of the resulting product showed that the nitrogen content (Kjeldahl) was 1.11%, indicating a 8.97% content of 3-APM in the form of maleimide. Using the standard asphaltenes dispersion test described above, it is found that 0.0625 g of polymeric material disperses 0.4% of the asphaltenes at 150 ° C.

Claims (2)

SUBJECT OF THE INVENTION A process for preparing a graft copolymer suitable as an additive in a lubricating oil or hydrocarbon motor fuel, characterized in that it is intimately mixed: a) an oil-soluble linear, saturated rubbery backbone ethylene propylene polymer; b) a graft monomer system comprising maleic acid or maleic anhydride and at least one other monomer selected from the group consisting of 1-olefins, N-vinylpyrrolidone, alkyl methacrylates, 16 alkyl acrylates, styrene and diisobutylene; than the initiator decomposition temperature, and then the temperature of the mixture is raised to or above the initiator decomposition temperature, followed by subsequent reaction of the monomer system with a polyamino compound containing one primary or secondary amino group. 2. The process of claim 1 wherein the monomer-grafted backbone polymer is dissolved in a solvent and then the initiator is intimately mixed with the solution while maintaining the temperature below the decomposition temperature of the initiator.