DE1084411B - Synthetic lubricating oil - Google Patents

Description

Synthetic Lubricating Oil The invention relates to synthetic lubricating oils based on ester, small amounts to improve their pressure absorption capacity contain certain additives.

Synthetic ester-based lubricating oils are known per se. Generally these oils are characterized by particularly advantageous viscosity values at low viscosity and high temperatures, especially when compared to mineral oils. In more recent Synthetic ester lubricating oils have gained increasing importance, and one time the most important current uses for these compounds is in lubrication of gas turbine systems such as those in turbine jet or turbine propeller machines for aircraft use. In general, however, is the pressure absorption capacity of these ester oils are not particularly high. In view of the increasingly severe conditions, that prevail in the lubrication of aircraft gas turbine systems, there is a strong There is a need for synthetic ester lubricating oils that have a higher pressure absorption capacity as the ester oil itself. The invention therefore relates to synthetic ester oils with additives to increase the pressure absorption capacity.

The invention relates to a synthetic lubricating oil based a fully esterified diester of an aliphatic dicarboxylic acid with a Alkanol, which contains small amounts of aliphatic Contains dicarboxylic acids with 6 to 10 carbon atoms per molecule. These are dicarboxylic acids Although very effective as a pressure absorbing agent, the lubricating oil can only be used to a limited extent - Quantities are added, since they are generally no more in ester lubricating oils are soluble than 0.10 percent by weight. It was further found that the pressure absorption capacity of ester lubricants by adding small amounts of as lubricant components known aryl phosphates and halogen-substituted alkyl phosphorus compounds to the mixture of ester lubricating oil and acid can further increase and that the combination of the dicarboxylic acid with small amounts of (a) a halogen-substituted alkyl phosphorus compound or (b) a mixture of an aryl phosphate and a halogen-substituted alkyl phosphorus compound an additional mixture results, which on the pressure absorption capacity of the synthetic Ester lubricant has a much greater impact than what the results suggest the addition of the individual components of this mixture could have been expected.

The invention therefore also includes mixtures of these synthetic lubricants with the specified dicarboxylic acids and a small amount of a halogenated one Alkyl phosphorus compound or a mixture of such a compound with one Aryl phosphate. It is known to use polycarboxylic acids, optionally mixed with monocarboxylic acids, Monocarboxylic acid esters and / or oxyaromatic carboxylic acids, as corrosion-preventing To use additives to mineral oils.

As anti-rust additives to mineral lubricating oils for textile machines, that work under conditions of high humidity, mixtures are already more oil-soluble Phosphoric acid esters with alkylated dicarboxylic acids or their mono- or dialkyl esters as well as with partial fatty acid esters of monohydric alcohols have been proposed.

- Furthermore, the use of trixylenyl phosphate is either on its own alone or together with small amounts of fatty oils, high molecular weight fatty acids, Fatty alcohols, phenols and other phosphoric acid esters are known as lubricants.

The use of phosphonic acid esters and phosphinic acid esters is also known or phosphine oxides containing a branched nonyl group as lubricants or hydraulic fluids. These compounds can be polymerized for thickening Esters can be added. In addition, numerous other compounds can be used with these compounds Supplements are added.

It is also known to use lubricating oils and greases, especially mineral ones -Oils, for the purpose of increasing the pressure absorption capacity, halogenated phosphonic acid monoesters to add.

Likewise, the use of organic phosphorus compounds is the various constitution, including halogen-containing, aromatically substituted Phosphine oxides, either on their own as lubricants or. Polishes or known as additives to 1Vlineralsc_berölen.

The already known additives for film lubricants include furthermore esters of one or more aromatic hydrocarbon radicals containing Phosphinic acids and primary aliphatic alcohols.

However, it was not known that the addition of small amounts of aliphatic Dicarboxylic acids with 6 to 10 carbon atoms have the ability of synthetic diester lubricating oils to accept pressure significantly increased, smell it was known that this effect was caused by the addition those mentioned above, which are already known in and of themselves as lubricant constituents Can increase phosphorus compounds in an unexpected manner, as below in individual is set out.

The ester oils used in the lubricating oils according to the invention include diesters of saturated aliphatic dicarboxylic acids with alcohols. These diesters have the general formula R C O O - R1 - C O O R, in which R is a straight or branched-chain alkyl radical of an alkanol with 7 to 13 carbon atoms, R, a denotes straight or branched C4 to C8 alkylene radical of a dicarboxylic acid and the total number of carbon atoms in the molecule about 20 to 36, preferably 22 to 26.

The dicarboxylic acids used according to the invention as pressure absorbing agents are saturated aliphatic dicarboxylic acids with 6 to 10 carbon atoms in the molecule. to these acids include adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid and isosebacic acid. Isosebacic acid is a mixture of Cr dicarboxylic acids, which about 60 to 90 percent by weight of a-ethyl suberic acid, about 5 to 25 percent by weight of a, a'-diethyladipic acid and contains about 5 to 15 weight percent sebacic acid. A typical acidity of this Art contains about 75 percent by weight of a-ethyl suberic acid, about 15 percent by weight of a, a = Diethyl adipic acid and about 10 percent by weight sebacic acid.

The aryl phosphates which can be used according to the invention are compounds of the general structural formula in which the radicals R are hydrogen or alkyl groups with 1 to 4 carbon atoms, e.g. B. methyl groups, examples of such phosphates are triphenyl = phosphate, phenyldicresyl phosphate, tricresyl phosphate, methyl <di-tert-butyl phosphate, etc.

The halogen-substituted alkylphosphorus compounds to be used according to the invention fall into three general classes: halophosphonates (e.g. chlorophosphonates), which include saturated and unsaturated mono-, di- and trihalogen-substituted alkylphosphonates of the general formula in which R, R 'and R "denote aliphatic hydrocarbon radicals or halogen-substituted aliphatic hydrocarbon radicals having 1 to 5, for example 2 to 4, carbon atoms and at least one of these radicals is substituted by halogen. For example, R can be a halogen-substituted alkyl radical 'R' is an alkyl radical or a halogen-substituted alkyl radical and R "is an alkylene radical having 2 to 5 carbon atoms. Particular examples of compounds that can be used according to the invention are mono-ß-chloro @ .thyhnonoäthylvinylphosphonat, bis (ß-chloroethyl) -vin @ lphosphonate, bis (ß-chloroethyl) -ß-chloroethylphosphionate, bis (ß-chloroethyl) ethylphosphonate, Bis (4-chloropentyl) butylene phosphonate, mono- (3-chloropentyl) butyl (1) propyl phosphonate, etc.

Halophosphites of the general formula in which R is a halogen-substituted alkyl group with 1 to 5, e.g. B. 2 to 4 carbon atoms and each of the radicals R '1 to 5, z. B. contains 2 to 4 carbon atoms and is either an alkyl radical or a halogen-substituted alkyl radical.

Halophosphates of the general formula in which R is a halogen-substituted alkyl group with 1 to 5, e.g. B. 2 to 4 carbon atoms and each of the radicals R '1 to 5, z. $. Contains 2 to 4 carbon atoms and is either an alkyl group or a halogen-substituted alkyl group.

The lubricating oil according to the invention consists for the most part made of a synthetic ester lubricating oil and contains a pressure absorption capacity improving amount of: additives according to the invention. The lubricating oil contains about 0.01 to 0.1 percent by weight, e.g. 0.04 to 0.06 percent by weight, of saturated aliphatic Dicarboxylic acid with 6 to 10 carbon atoms and can also be about 0.01 to 1.0 percent by weight halogen-substituted alkyl phosphorus compound or about 0.5 to 5.0 percent by weight, z. B. 1.0 to 3.0 percent by weight, aryl phosphate and about 0.1 to 0.8 percent by weight, z. B. 0.4 to 0.5 weight percent, halogen-substituted alkyl phosphorus compound contain, whereby all percentages relate to the amount of Sehmier oil, This lubricating oil mixture can also be used with other lubricating oils, such as. B, mineral oils or Add other synthetic lubricating oils such as corplex ester oils. Furthermore, one can give the lubricating oil other additives, such as oxidation inhibitors, z. B. phenothiazine or phenyl-9-naphthylamine, rust inhibitors such as petroleum sulfonates, lecithin, viscosity index improvers, z. B. polymethacrylic acid esters, polyethylene, etc. You can use the lubricating oils according to the invention also thicken into lubricating greases with the help of suitable grease thickeners.

Preferred embodiments of the invention are described in the following examples. Example 1 To a synthetic diester lubricant which contains 1.0 percent by weight of phenothiazine as an oxidation retarder, 1.0 percent by weight (based on the amount of oil) of tricresyl phosphate is added. The synthetic diester lubricating oil is a mixture of 50 percent by volume of adipic acid di-C $ oxoester and 50 percent by volume of adipic acid di-Cla-oxoester. The C8 oxo alcohol used to esterify adipic acid is made from copolymers of butylene and propylene with 7 carbon atoms. atoms in the molecule obtained by the axo process .. In a similar way, the C, 0-alcohol is obtained from tripropylene by the oxo process. The lubricating oil mixture is then examined for its pressure absorption capacity according to the Ryder gear test in accordance with standard specification MIL-L-7808 C. Since the relevant test standards are not available in the US system of measurement, the test results in the following tables and other information were also included in cbs / inch2.

Examples 2 to 9 Various additive mixtures are prepared in the ester lubricating oil according to Example 1 and their pressure absorption capacity is investigated. The results are shown in Table I. Table I. Additive to ester lubricating oil * (Percent by weight, Ryder based on oil quantity) Gearbox test Example Tn to _ Sebacin (ß-chlorine resistance cresyl ethyl) - phosphate acid vinylphos- lb @ / inch2 kg / cm2 phonate Base oil - - - 1750 123.0 1 1.0 - - 1860 130.8 2 ** - 0.050 - 1990 139.9 3 - 0.100 - 2150 151.2 4 - - 0.50 2350 165.2 5 1.0 0; 050 *** - 2100 147.6 6 1.0 0.10 - 2160 151.9 7 1.0-0.50 2370 166.6 8 - 0.05 0.50 2920 205.3 9 1; 0 0.05 0.50 3870 272.1 * An ester oil, consisting of 50 percent by volume, serves as the basis Adipic acid di-C $> oxoester and 50 percent by volume adipic acid di-Clo oxoester with a content of 1 weight percent phenothiazine. ** This Qemisgh also contains 1 percent by weight Complex ester made from 2 moles of C &: oxo alcohol, 2 moles Adipic acid and 1 mole of polyethylene glycol of a molecular weight of 200. However, this amount of complex ester has only a negligible influence on the Ryder transmission test. *** When replacing ß.054/0 5ebacic acid with 0.0ß0 /, iso- sebaic acid results in a load capacity of 1970 lbs / inch2 (138.5 kg / cm2). Table II Ryder transmission test, Resilience Example (additives in percent by weight) found calculated lbs / inch2 I kg / cm2 lbs / inch2 I kg / cm2 Base oil - - 1750 123.0 5 base oil -f-. 1 °% tricresyl phosphate + 0.05 ° / 0 2100 147.6 2100 147.6 Sebacic acid 6 Base oil + 1.0 % tricresyl phosphate -f- 0.10 ° / a 2260 158.9 2160 151.9 Sebacic acid 7 Base oil -f- 1.0 % tricresyl phosphate + 0.5 % bis- 2360 165.9 2370 166.6 (ß-chloroethyl) vinyl phosphonate 8 Base oil -E- 0.05 % sebacic acid + 0.5% bis- 2590 182.1 2920 205.3 (ß-chloroethyl) vinyl phosphonate 9 base oil -j- 1 "/ o tricresyl phosphate -f- 0.05% sebacin- 2700 189.8 3870 272.1 acid + 0.5 % bis (ß-chloroethyl) vinyl phosphonate As can be seen from the table above, the ester lubricating oil (base) shows a load capacity of 1750 lbs / inch2 (123 kg / cm2). The addition of 1.0 weight percent tricresyl phosphate (Example 1) increases the Ryder test value to 1860 lbs / inch2 (130.8 kg / cm2). An amount of 1.0 weight percent tricresyl phosphate therefore contributes 110 lbs / inch 2 (7.8 kg / cm 2) to the pressure capacity. Very small amounts of sebacic acid (Examples 2 and 3) increase the pressure absorption capacity approximately proportionally to the sebacic acid concentration. The blend of lubricating oil base and 0.05 weight percent sebacic acid exhibits a load capacity of 1990 lbs / in2 (139.9 kg / cm2), to which the sebacic acid contributes 240 lbs / in2 (16.9 kg / cm2). Bis (ß-chloroethyl) vinyl phosphonate is also effective on its own (Example 4). The blend of base lubricating oil and 0.5 weight percent of this additive exhibits a load capacity of 2350 lbs / in2 (165.2 kg / cm2); the bis (ß-chloroethyl) vinyl phosphonate thus contributes to the pressure absorption capacity of 600 lbs / inch2 (42.2 kg / cm2). While the values obtained in Examples 5, 6 and 7 are not higher than one could have calculated or expected based on the action of the individual components, Examples 8 and 9, as shown in the following table, give far more favorable results than them can be calculated from the individual effects of each of the additional components. Example 8 gives a value of 2920 lbs / in2 (205.3 kg / cm2) on the Ryder gear test. This is 330 lbs / in2 (23.2 kg / cm2) more than the load capacity of 2590 lbs / in2 (182.1 kg / cm2) that one might have expected considering the individual effects of 0.05 weight percent sebacic acid and 0.5 percent by weight bis (ß-chloroethyl) vinyl phosphonate to the pressure absorption capacity of the oil base of 1750 lbs / inch? (23; 0 kg / cMi?) Added. The lubricating oil according to Example 9, which differs from that according to Example 8 only by a further addition of 1.0 weight percent tricresyl phosphate, shows a pressure absorption capacity of 3870 lbs / inch 2 (272.1 kg / cm 2). This is 1170 lbs / inch2 (82.3 kg / cm2) more than the load capacity of 2700 lbs / inch2 (189.8 kg / 5m2) that would be calculated from the three individual additives. In these two examples there is therefore a clear synergistic effect. The results are summarized in the following table, examples of other compositions within the scope of the invention are given in the following table: Table III Composition of the lubricant, - parts by weight AB I C I D I E I F I G Diester oil Di-2-ethylhexyl sebacate ......... 55 70 - 30 100 - 40 Azelaic acid di-oxoester. . . . . . . . . . . . . .. - - 50 40 - 100 40 Adipic acid di-C "oxoester ............... 45 - 50 10 - - 10 Adipic acid di-C "oxoester................ - 30 - 20 - - 10 Dicarboxylic acid Isosebacic acid ......................... - - 0.1 0.05 - - - Azelaic acid ........................... 0.05 - - - 0.05 0.05 0.05 Adipic acid ............................ - 0; 05 - 0.05 - - - Aryl phosphate Triphenyl phosphate ...................... - 1; 0 - 1.0 - - - Phenyl dicresyl phosphate ................. 3.0 - - 1.0 - - 1.0 Halophosphorus compound Methyl di-tert-butyl phosphate ............ - - 1.0 - - - - Tris (2-chloroethyl) phosphate ............. - 0.3 - - - 0.2 - Bis (ß-chloroethyl) vinyl phosphonate .. ...... - - 0.5 - 0.5 - - Bis (p-chloroethyl) ethyl phosphonate ....... - 0.5 - - - - 0.5 Tris (2-chloroethyl) phosphite .............. 0.3 - - - - 0.3 0.1 Other accessories . . . . . . . ... . . . . . . . . . . 1 - 1 - - 1 1 - Phenothiazine ....... Phenyl-a naphthylamine. . . . . . . . . . . . . . . . . - 1 - 1 - - 1

Claims (4)

PATENT CLAIMS: 1. Synthetic lubricating oil based on a full esterified diester of an aliphatic dicarboxylic acid with an alkanol, thereby characterized in that it is about 0.01 to 0.10 percent by weight, based on the amount of diester, on a saturated aliphatic dicarboxylic acid with 6 to 10 carbon atoms per molecule contains. 2. Synthetic lubricating oil according to claim 1, characterized in that there is also 0.01 to 1.0 percent by weight of one as a lubricant component contains halogen-substituted alkyl phosphorus compounds known per se. 3. Synthetic Lubricating oil according to Claim 1, characterized in that it also contains 0.1 to 0.8 percent by weight of a halogen-substituted substance known per se as a lubricant component Alkyl phosphorus compound and 0.5 to 5.0 weight percent of one as a lubricant ingredient contains known triaryl phosphate. 4. Synthetic lubricating oil according to claim 3, characterized in that the dicarboxylic acid sebacic acid, the aryl phosphate Tricresyl phosphate and the halogen-substituted alkyl phosphorus compound bis (ß-chloroethyl) vinyl phosphonate is. -Respected publications German patents No. 929 207, 912 251, 879138, 865 340, 851237; Chemisches Zentralblatt, 1951, I, p. 1827.