DE947186C - Additive to lubricating oils and heating oils - Google Patents

Description

Addition to. Lubricating Oils and Hair Oils The invention relates to use of a copolymer as an additive to lubricating oils and heating oils, whereby lubricating oils receives; which under the conditions prevailing in internal combustion engines are extremely resistant to the formation of oil sludge and their viscosity changes with the temperature changes only slowly, while the fuel oils obtained by the invention Addition a very extensive stability is given.

According to the invention, the lubricating oil is at least 0.1 percent by weight an oil-soluble copolymer added, the polymeric constituents of which are essentially from a polymerized ester of acrylic acid or an α-substituted acrylic acid with a saturated aliphatic alcohol having at least 8 carbon atoms and from a polymerized, ethylenically unsaturated, a basic tertiary amino group containing compound exist. In general, between 0.1 and 20 percent by weight and appropriately between i and. 5 percent by weight, based on the lubricating oil, of one Copolymer used, welohes as a third component an N-hydrocarbon-substituted Contains acrylamide.

The copolymer consisting of two components contains 75 to 99 and preferably up to 98 parts by weight of alkylacrylic acid ester and 1 to 25 and advantageously 2 to 10 parts by weight of the ethylenically unsaturated compound containing a basic tertiary amino group per 100 parts of the copolymer.

In a copolymer containing the three components, the proportions should expediently be 65 to 97.5 parts by weight of acrylic acid ester, 0.3 to 20 parts by weight of the ethylenically unsaturated compound containing a basic tertiary amino group and 2 to 15 parts by weight of W-hydrocarbon-substituted acrylamide. Appropriately, this should consist of three components. existing copolymer contain 75 to 92.5 parts by weight of alkyl acrylic acid ester, 2 to 10 parts by weight of the basic tertiary amino compound and 2.5 to 10 parts by weight of the N-hydrocarbon-substituted acrylamide per 100 parts by weight of the copolymer. It is already known to add polymerized esters of acrylic and methacrylic acid to lubricating oils in order to improve the viscosity index. With the additives according to the invention, consisting of very specific components, an improvement in lubricity of about thirty times is achieved compared with the oils containing the known additives.

The copolymers used according to the invention contain as essential Constituents always an alhylacrylic acid ester and the ethylenically unsaturated compound with a basic tertiary amino group. The ethylenically unsaturated compound can .be a polymerizable, basic tertiary amino compound in which the tertiary Amino nitrogen is a member of a heterocyclic ring and is polymerizable Ethylene double bond is * outside the ring, - but sits on the * ring, such as B. 2-vinyl pyridine. It can also be a polymerizable, basic tertiary Amino compound can be used in which the tertiary amino nitrogen is acyclic is; z. B, p-dimethyl-aminomethylstyrene and the basic tertiary amino-alkyl acrylic acid esters.

The basic tertiary amino-alkyl acrylic acid esters "include the Esters of acrylic acid: re and -substituted acrylic acids with a basic tertiary Alkanols containing alkylamine groups. Preferred esters of this type are the esters of acrylic acid and α-substituted, advantageously α-hydrocarbon-substituted Acrylic acids, in which the two amino hydrogens are replaced by low aliphatic, capable of cyclization hydrocarbon radicals are replaced, e.g. B. the esters the lower amino alkanols N-disubstituted with lower alkyl groups. the The most suitable acrylic acid esters of alkylamino-alkanols are the esters of aerylic acid and methacrylic acid.

The preferred copolymers according to the invention consist of the alkyl acrylic acid esters, the ethylenically unsaturated, basic tertiary amino compound and, as the third component, an N-hydrocarbon-substituted acrylic amide. Such acrylamides include the amides of acrylic acid and α-substituted, specifically advantageously α-hydrocarbon-substituted acrylic acids in which the nitrogen of the amide group bears at least one hydrocarbon radical having 6 to 18 carbon atoms. The hydrocarbon radical is an alkyl, cycloalkyl or aryl group, and the total number of hydrocarbon substituents on the a-carbon atom and on the nitrogen of the amide group must not exceed 2. -The preferred acrylamide is represented by the following formula: Here R2 is hydrogen or alkyl, R3 is hydrogen or a hydrocarbon radical with 6 to 18 carbon atoms and R4 is a hydrocarbon radical with 6 to 18 carbon atoms. The total number of hydrocarbon substituents on the a-carbon atom and on the nitrogen of the acid of the amide group does not exceed a.

A particularly suitable subgroup of the preferred acrylamides are. the amides of acrylic acid and of the a-substituted acrylic acids, in which the a-substituent is a lower alkyl radical and the nitrogen of the acid amide group is an aryl radical, and expediently carries phenyl or alkylated phenyl.

The misoh polymers can simply be added to the lubricating oil while stirring ordinary temperatures, or it can also be a mixture of the lubricating oil and the copolymer while stirring to elevated temperatures from Z. B. 100 to 130 'are heated. The above in the remainder of the description specified quantities. are parts by weight, unless otherwise specified.

show that the copolymer additives according to the invention are also one result in good and sometimes even greater viscosity improvement than those previously known Additions of polymeric acrylic acid alkanol esters, e.g. B. Met'hacrylsäurelaurylester. This improvement occurs not only in mixed base oils and solvent-extracted oils Lubricating oils on paraffin bass, but also with the synthetic ester-like lubricating oils a. The copolymer additives according to the invention consisting of three components improve viscosity significantly more than either previously known and used Polymers as well as the mixed polymer additives according to the invention, consisting of two components.

A great advantage of the mixed polymer additives according to the invention lies in their ability to keep the so-called oil sludge or debris in suspension. Tests have shown that both the two- and the three-component Copolymers According to the invention, as additives to lubricating oils, the ability of the oil to remove dirt to suspend to enlarge about 7o times. This ability of the said Lubricating oils containing mixed polymers is also about 3oom times larger than lubricating oils, which are built similar to the copolymers according to the invention, but outside contain copolymers lying within the scope of the invention. So z. B. Copolymers which contain non-basic amino groups, e.g. B. Methacry1säurelaurylester-Methacrylsäurephenylät'hylaminoäthylester (95: 5), and copolymers which contain no amino group at all, e.g. B. Methacrylic acid lauryl ester-2-nitro-2-methylpropyl methacrylate, ester (95: 5), as an additive to lubricating oils no more than about 1 / aoo of the dirt-suspending effect the lubricating oils containing the copolymer additives according to the invention.

Tests in a Lauson machine clearly show the much better ones Properties of the two- and three-component copolymers containing Lubricating oils compared to unmodified lubricating oil. The improvement is up to 701/9. Good results in these trials have been obtained with a large variety achieved by copolymer additives according to the invention, such. B. with copolymers from 85: 5: 1o-methacrylic acid lauryl ester-methacrylic acid-ß-diethylaminoethyl ester-methacrylanilide, 95: 5-methacrylic acid lauryl ester-p-dimethylaminomethylstyrene, 85: 5: 1o-methacrylic acid lauryl ester-2-methyl-5-vinylpyridine-methacrylanilide and 95: 5-methacrylic acid lauryl ester-Methacrylsäu @ re-ß-dimethylaminoethyl ester.

The tests in a Lauson machine also clearly show the considerable improvement of lubricating oils which contain the three-component copolymers according to the invention together with a commercially available sulfur-containing terpene as corrosion protection and antioxidant, compared with i. the lubricating oils containing no additives at all, 2. the lubricating oils containing only the sulfur-containing terpene and 3. the lubricating oils containing the sulfur-containing terpene plus a 90: io copolymer of lauryl methacrylate and methacrylanilide. The effectiveness of the lubricating oils improved according to the invention can also be demonstrated by the carbon suspension test used as a standard operating test for determining the cleaning effect in the case of lubricating oils. For this test, 30 g of finely divided sewer soot are rubbed with 3009 mineral oil for 24 hours. An io-g sample of the resulting pulp is placed in a 1i2 g petroleum sample bottle, whereupon 0.2 g of the mixed polymer to be tested dissolved in hydrocarbons of the petroleum fraction boiling at 150 to 28o ° is added to the bottle up to Fill the throat with these hydrocarbons, shake the resulting suspension vigorously and then observe the settling rate. This carbon suspension test shows the astonishing effectiveness of the copolymer additives according to the invention even in those cases in which one or more of the components of the copolymer are only present in a relatively small amount. If you compare z. B. a control sample, in which the lubricating oil contains only polymethacrylic acid ester, with a lubricating oil containing a 90: 0.5: 9.5 copolymer of methacrylic acid lau.ryl ester-methacrylic acid-ß-diethylaminoethyl ester methacrylanilide, the latter is in the suspension test according to 24 hours by about 61/2 times, after 48 hours by about 6 times, after 72 hours by about 51/2 times and even after 7 days by more than 3 times more effective than the control sample containing the lauryl methacrylate. This shows the surprising effectiveness of the copolymers described as lubricating oil additives and is characteristic of both the two- and three-component copolymers according to the invention.

The acrylic acid alkyl esters preferably used in the copolymers according to the invention are the esters of acrylic acid and a-substituted acrylic acids in which the a-substituent, if any, is a lower alkyl radical and the alcohol component is formed from a saturated aliphatic alcohol with at least 8 carbon atoms . To form the Misohpolymerisate octyl and decyl esters of these acids can be used, although the esters of saturated aliphatic Al'ko'hole having 12 to 1 8 carbon atoms, z,. B. the dodecyl, tetradecyl, hexadecyl and octadecyl esters are preferred because they result in copolymers which are more soluble in lubricating oils than the esters of alcohols having 8 to 10 carbon atoms.

Others which are suitable as a constituent of the composite polymers according to the invention Acrylic acid alkyl esters include the 2-ethylhexyl and 2-butyloctyl esters of these acrylic acids. Because they are more accessible, the esters are of acrylic acid and α-hydrocarbyl-substituted acrylic acids in which the α-substituent carries 1 to 2 carbon atoms, d. H. the esters of methacrylic acid and ethacrylic acid, preferred.

The polymerizable, ethylenically unsaturated, a basic tertiary Amino group-containing compounds which are an essential part of the Make up copolymers described above include compounds in which the tertiary amino nitrogen is a member of a heterocyclic ring and the polymerizable ethylenic double bond is outside the ring, however, is associated with it. Examples are the vinyl pyridines, e.g. B. 2-vinylpyri, din, 4-vinyl pyridine and 2-ethyl-5-vinyl pyridine. Compounds in which the tertiary Amino nitrogen is acyclic and not bound directly to an aromatic nucleus, z. B. the polymerisierharen containing a basic tertiary F, nino nitrogen atom Hydrocarbons, z. B. p-Dimethylaminoethylstyrene and p-Dimethylaminomethylstyrene, as well as the acrylic acid esters containing a basic tertiary amino group likewise suitable as constituents of the copolymers according to the invention.

The latter are even preferred. Examples of this are among others the acrylic acid dialkylaminoalkyl esters and the corresponding α-hydrocarbon-substituted Acrylic acid esters, e.g. B. methacrylic acid-ß-dimethylanninoethyl ester, methacrylic acid-ß-diethylamihoäthylester, Methacrylic acid-ß-di- (n-butyl) = aminoethyl ester, acrylic acid ß-diethylaminoethyl ester, Acrylic acid dicycloalkylaminoalkyl esters and the corresponding esters of the α-hydrocarbon-substituted Acrylic acids, e.g. methacrylic acid ß-dicyclohexylethyl ester, acrylic acid dialkylaminocycloalkyl ester ,. and the corresponding esters of the α-hydrocarbon-substituted acrylic acids, z. B. Methacrylic acid a- (diethylamino) cyclohexyl ester.

The in the polymerizable; ethylenically unsaturated compound with. tertiary amino nitrogen containing tertiary amino group must be basic, in order to come into question as a component of the misoh polymers according to the invention. So is z. B. a tertiary amino nitrogen bonded directly to a benzene nucleus not basic enough to give the desired properties, which is why such Connections are expressly excluded.

The three-component copolymers are preferred according to the invention used, which not only acrylic acid esters of long-chain alkanols and a polymerizable Compound with basic tertiary amino group, but also N-hydrocarbon-substituted Acryl.amide included. Specific examples of such acrylamides are among others N-alkyl substituted acrylamides and methacrylamides, e.g. B. hexyl, decyl, tetradecyl, Oetadecylacrylamides and methylacrylamides, N-cycloalkyl-substituted compounds, z. B. N-Cyolohexylacrylamid und -methacrylamid, and N-arylsubstituted acrylamides, z. B. N-P: henyl, N-p-tolyl, N-o-tolyl, N-naphthylacrylamides, and 'the corresponding Methacrylamides. The N-alkyl-substituted acrylamides must, although they are products with satisfactory solubility to achieve the same properties are used in larger amounts than the N-aryl-substituted acrylamides.

The copolymers containing N-arylacrylamides are special suitable for improving the viscosity index of lubricating oils. The N-naphthyl-substituted Acrylamides maintain products with lower solubility of both the monomeric and also to give the polymeric compound than the N-phenyl-substituted acrylamides. The N = phenyl-substituted acrylamides are therefore preferred. _ Because of her in general better oil solubility and the absence of side reactions in their production should all constituents of the copolymer additives according to the invention, d. H. the Acrylic acid esters of the long-chain alkanols, the polymerizable ones, a basic one compounds containing tertiary amino groups and, if appropriate, the N = hydrocarbon-substituted ones Acrylamides, no reactive hydrogen, d. H. no Zerewitinoff hydrogen, contain, with the exception of the hydrogen attached to the acid amide nitrogen ..

In the production of the mixed polymers used according to the invention the polymerization conditions should be chosen so that the copolymer obtained is homogeneous. A monomer mixture should be used which is at the polymerization temperature is homogeneous and in which the individual monomers easily form a copolymer with one another form. In particular, in the case of the preferred three-component mixed polymer, an acrylamide can be used, - that at the polymerization temperature in the mixture from the monomeric, long-chain alkyl acrylic acid ester and the monomeric tertiary amino-containing compound is soluble .. If an acrylamide is used which is in the mixture of the other two monomers is not completely soluble, so the mixed polymer made from it contains a certain amount of homopolymer, which is insoluble in most lubricating oils.

The molecular weight of the copolymers used according to the invention is not important. Nevertheless, copolymers with an extremely high molecular weight maintain to be less useful than similar copolymers with lower molecular weight, since the former can cause undesirable thickening of the lubricating oil and also more tend to change their properties when subjected to mechanical stress are exposed than the low molecular weight copolymers. The molecular weight the blend polymer can be obtained by monitoring the polymerization process or can be regulated by post-treatment of a high molecular weight polymer. To the Example, if the degree of polymerization of the copolymer is reduced by that the corresponding monomers in the presence of approximately the same amount by weight of a neutral, light mineral oil or a lubricating oil that does not polymerize Contains inhibitors in appreciable quantities. The molecular weight of a mixed polymer, whose molecular weight is too high for a lubricant to have optimal properties to grant, can be reduced by the fact that the copolymer at 35 to 38 ° C on one roller, the two roller rollers of which rotate at different speeds, processed. In this case, Modifiers can be used, such as. B. Antioxidants and or or mercaptans are added.

The lubricant compositions of the invention and in particular those containing a three-component copolymer are therefore excellent, as they have very improved viscosity indices show and against a Dirt formation and deposition are resistant. At the same time they only show slightly increased viscosities at low temperature in contrast to the much larger ones Viscosity increases in the previously known lubricant additives, which Increase the viscosity index of the oil in the same way, but not noticeably Have an influence on the pollution of the oil.

The copolymers described above are not based on one certain group of each individual component, provided that the The total amount of each of these components does not exceed the amount ranges given above. For example, a copolymer containing 40 parts by weight of an alkyl acrylic acid ester with 12 carbon atoms in the alkyl chain, 40 parts by weight of an alkyl methacrylic acid ester with 10 carbon atoms in the alkyl chain, 10 parts by weight of ß-di- (n-propyl) -aminoethyl-acrylic acid ester and contains 10 parts by weight of ß-dimethylaminoethyl methacrylic acid ester, as a two-component copolymer well suited. Likewise, a three-component copolymer is one good to use, the 40 parts by weight of an alkyl acrylic acid ester with 10 carbons in the alkyl chain, 45 parts by weight of the ester of methacrylic acid with the commercially available, technical alcohols obtained by reducing the fatty acids in coconut oils, 5 parts by weight of ß-diethylaminoethyl acrylic acid ester, 5 parts by weight of ß-dimethylaminoethyl methacrylic acid ester, 2.5 parts by weight of N-phenylacrylamide and 2.5 parts by weight of N- (p-tolyl) methacrylamide contains.

The invention is applicable to lubricating oils in general. Such Lubricating oils include all types of petroleum derived oils; H. the paraffinic, naphthenic and mixed base oils and also ester type lubricating oil, such as e.g. B. Di-2-ethylhexyl sebacic acid ester. Preferably contain the invention Compositions Lubricating oils that boil at about 345 ° or higher at i at. the In addition to the copolymers described above, lubricating oils can also be used in it conventional modifying agents, dissolved or suspended, which the oil has other give favorable properties, e.g. B. antioxidants or the like. Also can the copolymers according to the invention in power transmission fluids, such as them used in gears to achieve improved compositions will.

The amount of the copolymer used in the lubricating oil should usually be not less than 0.1 percent by weight and not more than 20 '/ 9 based on the lubricating oil. In the meantime, preliminary batches of the oil can be made in which, for the sake of easier handling, the oil contains 50 percent by weight or more of the copolymer before dilution. For engine lubricants, 1 to 5019 of the mixed polymerizate, based on the oil, is preferred, the exact amount depending in each individual case on the desired cleaning effect and increase in the viscosity index in the oil. It is also possible to add more than one of the copolymers described to the oil , the total amount of the copolymers added having to be within the stated range.

Of course, the copolymer must be soluble in the lubricating oil. However, this only means that the copolymer is in the amount in the lubricating oil solves; in which it is used. The introduction of the copolymer into the oil can be done in any way such as. B. by simply mixing under Stir at ordinary temperatures, or it can be a mixture of the oil and the copolymer are heated to an elevated temperature with stirring.

The copolymers to be used according to the invention are not only valuable additives to lubricating oils, but are also suitable as additives' too Heavy oils, which contain at least a substantial amount of catalytically cracked oil contain. Heavy oils, d. H. Hydrocarbon oils above the gasoline range, the used as fuel and heating oils as well as diesel fuel are not only from a relatively narrow boiling range of petroleum hydrocarbon distillates, but also obtained by thermal cracking and catalytic cracking. Heavy oils often tend to decompose during storage, and most importantly, is catalytic Cracked heavy oil is often very unstable and largely decomposes during storage.

It has surprisingly been found that heavy oils and in particular catalytically cracked heavy oils containing a small amount of the above Copolymer contain, a much better resistance to Have dirt bilidüng and at the same time generally a significantly improved Show color stability.

The concentration of the copolymer in the heavy oil can be significantly lower than the concentration in lubricating oils. In general, a concentration of at least 0.1 percent by weight, based on the oil, is used, and a concentration of 0.1 percent by weight, based on the oil, is usually not exceeded, unless in the preparation of preliminary batches, containing 50 percent by weight or more of the interpolymer based on the oil for ease of handling and use prior to dilution of the oil. Concentrations between o, oo2 and o, oi percent by weight, based on the heavy oil, are usually sufficient, while the additives to lubricating oils, as already mentioned, are 0.1 to 20 and preferably 1 to 5 percent by weight. The copolymers can be added to the heavy oil together with customary antioxidants and metal deactivators and used with them, these additives optionally serving to improve other beneficial properties of the oil. The advantage of the invention is that it offers economical and practical ways to greatly improve the performance of lubricating oils. An extraordinary advantage of the invention is the improvement of lubricating oils used for internal combustion engines because of the continued high lubricating performance of the composition according to the invention under the prevailing conditions. The temperature of the lubricant in an internal combustion engine is between 70 and 1q.5 ° and an average of about 93 ° while the engine is running. In addition, the lubricant is temporarily exposed to the much higher ignition temperatures for a short time. The performance under these conditions together with favorable properties at lower temperatures determine the effectiveness of the lubricant. In an effective lubricant for internal combustion engines, therefore, an excellent cleaning effect under severe conditions must be combined with a high viscosity index and a relatively low viscosity at ordinary temperature. The lubricating oil compositions according to the invention and in particular those which contain the three-component copolymer, show this combination of favorable properties to a greater extent than all previously known lubricant compositions.

Claims (9)

PATENT CLAIMS: i. Use of a copolymer, consisting of from 75 to 99 parts by weight of an acrylic acid ester of the general formula C H2 = C R-C O O R1, where R is hydrogen or an alkyl radical and R1 is the hydrocarbon radical a saturated aliphatic alcohol having at least 8 carbon atoms and i to 25 parts by weight of a polymerizable, ethylenically unsaturated, a basic tertiary amino group-containing compound in which the tertiary Amino nitrogen is a member of a heterocyclic ring and is polymerizable Ethylene double bond is outside the ring, but immediately on Ring sits, or in which the tertiary amino nitrogen is acyclic, in amounts from 0.1 to 5 percent by weight of the total lubricant as an additive to lubricating oils based on mineral oils and synthetic oils. 2. Use of a copolymer according to claim i in amounts of o, ooi to o, i percent by weight of the total agent as Additive to heating oils. 3. Embodiment of the invention according to claim i and 2, characterized by a further content of the copolymer of 2 to 15 parts by weight of an N-hydrocarbon-substituted acrylamide of the general formula in which R2 is hydrogen or an alkyl radical, R3 is hydrogen or a hydrocarbon radical with 6 to 18 carbon atoms and R4 is a hydrocarbon radical with 6 to 18 carbon atoms and the total number of hydrocarbon substituents in the molecule does not exceed 2. 4. Embodiment of the invention according to claim i to 3, characterized in that a methacrylic acid ester or a Äthacry1äureester used. will. 5. Embodiment of the invention according to claim i to 3, characterized characterized in that R1 is the hydrocarbon radical of a saturated aliphatic Means alcohol with 12 to 18 carbon atoms. 6. Embodiment of the invention according to claim i to 5, characterized in that the ethylenically unsaturated, a basic tertiary amino group containing compound is 2-vinylpyridine. 7th Embodiment of the invention according to claim i to 5, characterized in that the ethylenically unsaturated compound containing a basic tertiary amino group is p-Dimefhyl-aminom @ ethylstyrene. B. Embodiment of the invention according to claim i to 5, characterized in that the ethylenically unsaturated one is basic tertiary amino group-containing compound is a basic tertiary amino acid ester is. 9. Embodiment of the invention according to claim 3, characterized in that: ß the N-hydrocarbon-substituted acrylamide is mebhacrylanilide.