EP0877074A2 - Ester based lubricating oil and the use of metal dissolution inhibitors in the same - Google Patents

Abstract

The lubricating oil comprises 80-99 wt.% synthetic and/or natural carboxylic acid esters, an additive to improve the viscosity, antioxidant, especially based on sterically hindered phenols and amines, foam inhibitor, detergent, dispersant, demulsifier, corrosion inhibitor, and antiwear additive, and also an additive, preferably in an amount of 0.01-0.5 wt.%, of an inhibitor against chemical elimination and/or extraction of tin, copper or iron, especially lead alloys.

Description

The invention has a lubricating oil and inhibitors against the Inclusion of metals in the same subject.

Lubricating oils usually have a viscosity of 10 to 1,500 mm ² sec ^-1 at working temperature and are intended to reduce the sliding but also rolling friction between metallic and / or ceramic materials. In addition to this task, for example in the case of engine oils, the oil film remaining in the combustion chamber should burn as residue-free as possible. For this it is necessary, on the one hand, that the oil film has a particularly small layer thickness in order to keep the oil consumption as low as possible and, on the other hand, that oxygen atoms are built into the oil molecules in order to ensure residue-free combustion, so that no additional undesirable particle emission is present in the exhaust gases from the engine. Furthermore, it is desirable that contaminants, which are deposited in the machine elements, in particular the bearings, be dispersed from the engine oil, so that the functionality of the machine elements is ensured.

It is particularly important that the lubricating oils have a wide temperature range a constant viscosity have, so that on the one hand even at lower temperatures no greater resistance when moving the machine elements arises and on the other hand too thin at high temperatures Film of the lubricating oil is avoided, for which additives are used be so that the desired lubricating effect is ensured. Furthermore, additives are known in lubricating oils, which the Corrosion of steel components but also aluminum, as is the case for avoid the pistons, or at least reduce them should.

Although mineral lubricating oils are also broken down by microorganisms subject to nature, there is a desire to mineral lubricating oils, through natural and / or artificial To replace carboxylic acid esters. These lubricating oils have different ones Advantages on. So it becomes largely residue-free Burn these compounds in an internal combustion engine it with spark or auto ignition, due to the oxygen atoms promoted in the molecule. Furthermore, the viscosity of the basic substance by choosing organic carboxylic acids as well the alcohols can be controlled particularly easily. By known Additives can also affect the viscosity behavior over a wide range Temperature ranges as well as the corrosion behavior influenced will.

Another advantage of the esters is that the ester bond of microorganisms much lighter than the carbon-carbon bond broken down by n- or iso-hydrocarbons can be. This easier microbiological degradability special attention is given to the fact that with a exponentially increasing number of vehicles, even at better motors, hydraulic motors and. Absolutely the like There is a risk that larger amounts of such lubricating oils, be it due to accidents, leaky crankcase u. The like Environment.

In road vehicles, there is the further disadvantage that Precipitates these oils washed off the road and reach the sewage treatment plants via the sewer system and there for a long-term burden may be responsible.

Carboxylic acid ester oils were initially used for aircraft turbines used and already have the conventional ones mineral oils replaced because the oil change times on the Engine overhaul times could be extended. Carboxylic acid ester oils are usually from dicarboxylic acids u. between Sebacic, adipic and azelaic acid. As alcohols are preferred those by oxosynthesis or aldol condensation obtained alcohols used. Corresponding carboxylic acid ester oils are for example in EP 0 264 842 A2 or US 5,057,247 A.

Have unpublished investigations by OMV AG Austria now surprisingly shown that in used carboxylic acid ester oils an increased content of lead, but also tin, copper and iron. These investigations initially failed interpreted to mean that the large amounts of lead, which were found in the lubricant on the extraction of Lead deposits caused by the leaded fuel in the engine templates that are due. Regardless of that, too for internal combustion engines that do not contain a lead Fuel operated, an increase in the lead content in the Lubricating oil can be found. Investigations have now shown that the bearing metals, which, as is known, contain lead also the cages of ball bearings, which also contain lead by which ester oils are attacked. Such one Attack, be it through complex dissolution of the metals, in particular of lead or chemical dissolution of it is for the inventory of bearing metals or the like from a subordinate one Meaning, however, come across again and therefore not over the fuel, but via a microbiologically light degradable lubricating oil lead and other metals in the environment.

The present invention has for its object a To create lubricating oil that has the lowest absorption capacity for tin, copper, iron, especially for lead and / or their Compounds at room temperature as well as elevated temperatures has that, including the additives, rapidly biodegradable and is not an additional biological burden for the environment represents. Furthermore, the additions which are the inclusion of metals or their compounds in engine oil prevent that Do not negatively influence the viscosity behavior of the lubricating oil, and with hydraulic oils, which are both as working medium and serve as lubricating oil, the water and air separation behavior don't worsen.

The lubricating oil according to the invention for machines, in particular for Internal combustion engines with spark and / or spark ignition, hydraulic motors or the like with a content of 80% by weight up to 99% by weight of artificial and / or natural carboxylic acid esters, an additive to improve the viscosity behavior, Antioxidants, especially based on sterically hindered Phenols and amines, anti-foaming agents, detergents, dispersants, Demulsifiers, corrosion inhibitors, wear protection, consists essentially in that it is an additive, preferably 0.01 wt .-% to 0.5 wt .-%, an inhibitor against chemical extraction and / or extraction of tin, copper, Iron, and especially lead, from alloys, preferably Bearing alloys and cage alloys.

It was quite surprising that an oil was an inhibitor can be added, which is the chemical or physical Extraction of lead and at the same time tin, iron and copper prevented without a deterioration in the property profile of the lubricating oil. As is well known, lead and copper are although extremely soft, particularly chemically resistant Metals. This is how lead and copper stand in electrochemical Voltage series, which indicates the chemical resistance, particularly high up. It was quite surprising that chemical substances are present that represent a physical or chemical extraction of lead, but also copper, tin and iron can prevent, and the same in smallest amounts are effective, with protection of these inhibitors preferably works in relatively small concentrations. The mechanism of action is not known per se, but there is Possibility that the inhibitor together with the metals a kind of protective film, e.g. B. a complex or the like. Is formed, which against the extraction or chemical dissolution of the Metals in the metallic alloy works.

wobei R ein Methyl-, Ethyl-, n-Propyl-, iso-Propyl-, n-Butyl, iso-Butyl-, Octyl- und Dodecylrest bedeutet, so ist ein besonders wirksamer Inhibitor gegeben, der gleichzeitig eine geringe biologische Toxizität aufweist und auch oxidativ besonders einfach abbaubar ist und damit keine zusätzlichen Partikel im Abgas verursacht. Gallussäureester sind als Oxidationsinhibitoren für Pharmazeutika bekannt, und es war durchaus überraschend, daß diese Substanzen einerseits die Aufnahme von Blei bzw. Kupfer, Zinn und Eisen sowie deren Verbindungen in einen Carbonesteröl verhindern und gleichzeitig einer quantitaviven Oxidation, des in einem Verbrennungsmotor zurückbleibenden Ölfilms, soweit derselbe oxidativ angegriffen ist, nicht verzögert; obwohl Wasser- und Luftabscheideverhalten in der Regel durch polare Zusätze verschlechtert werden, konnte keine negative Veränderung des Eigenschaftsprofiles aufgefunden werden, wobei weiters keine zusätzlichen Ablagerungen bedingt waren.If the additive is present or has the same formula as a gallic acid ester

where R is a methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, octyl and dodecyl radical, there is a particularly effective inhibitor which at the same time has low biological toxicity and is also particularly easy to decompose oxidatively and therefore does not cause any additional particles in the exhaust gas. Gallic acid esters are known as oxidation inhibitors for pharmaceuticals, and it was quite surprising that these substances on the one hand prevent the uptake of lead or copper, tin and iron and their compounds in a carbonic ester oil and at the same time a quantitative oxidation of the oil film remaining in an internal combustion engine, to the extent it is oxidatively attacked, not delayed; Although water and air separation behavior are usually worsened by polar additives, no negative change in the property profile could be found, furthermore no additional deposits were necessary.

The additive for the lubricating oil can consist of phenothiazine or have such an additive, phenothiazine also is known as an oxidation inhibitor and again surprising was that such a substance extraction or chemical removal of the listed metals from machine components can prevent and furthermore no additional Particle emission and the water and air separation behavior not deteriorated, as well as no additional Deposits.

The addition can be according to another feature of the present Invention consist of phenoxazine or have the same. A Phenoxazine is also known as an antioxidant and it was quite surprising that this connection was also the Extraction of tin, copper, iron and especially lead an alloy or the chemical extraction of these metals can prevent from an alloy, further the Particle emission in the exhaust gas of an internal combustion engine due to of these substances is not increased and no additional Deposits can be caused.

wobei R ein Methyl-, Ethyl-, n-Propyl-, iso-Propyl-, n-Butyl, iso-Butyl-, Octyl- und Dodecylrest bedeutet, insbesondere in einer Menge von 0,01 Gew.-% bis 0,5 Gew.-%, als Inhibitor gegen Zinn, Kupfer-, Eisen, insbesondere Bleiaufnahme, für ein Schmieröl mit 80 Gew.-% bis 99 Gew.-% mit künstlichen und/oder natürlichen Carbonsäureestern für Maschinen, insbesondere Verbrennungsmaschinen, mit Fremd- und/oder Eigenzündung, hydraulische Motoren od. dgl. Die Wirksamkeit einer derartigen chemischen Substanz gegen die Extraktion von den angeführten Metallen, insbesondere Blei, aus einer Legierung bzw. chemisches Herauslösen aus einer Legierung war durchaus überraschend und nicht naheliegend, da der Einsatz dieser chemischen Verbindung bislang als Antioxidationsmittel bekannt war und Blei als besonders resistentes Metall vielfältig zum Einsatz kommt. Von besonderer Bedeutung war, daß weder die Viskositätsveränderung noch die Partikelemission negativ beeinflußt wurde, sondern, obwohl als Antioxidant eingesetzt, die quantitative Oxidation des Ölfilmes zur Verhinderung von zusätzlichen Partikeln durchgeführt werden kann und die Viskosität ebenfalls in weiten Grenzen beibehalten wird, sowie keine zusätzlichen Ablagerungen bedingt werden.The invention further consists in the use of gallic acid esters of the following formula

where R is a methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, octyl and dodecyl radical, in particular in an amount of 0.01% by weight to 0.5 % By weight, as an inhibitor against tin, copper, iron, in particular lead absorption, for a lubricating oil with 80% by weight to 99% by weight with artificial and / or natural carboxylic acid esters for machines, in particular internal combustion engines, with extraneous and / or auto-ignition, hydraulic motors or the like. The effectiveness of such a chemical substance against the extraction of the metals mentioned, in particular lead, from an alloy or chemical extraction from an alloy was quite surprising and not obvious since the use of this chemical compound was previously known as an antioxidant and lead is used in many different ways as a particularly resistant metal. Of particular importance was that neither the change in viscosity nor the particle emission was adversely affected, but, although used as an antioxidant, the quantitative oxidation of the oil film to prevent additional particles can be carried out and the viscosity is also maintained within wide limits, and no additional deposits be conditioned.

The invention further consists in the use of Phenothiazine, in particular in an amount of 0.01 wt .-% to 0.5% by weight, as an inhibitor against lead absorption for a lubricating oil with 80 wt.% to 99 wt.% artificial and / or natural Carboxylic acid esters for machines, especially internal combustion engines, with spark and / or auto ignition, hydraulic Motors or the like. It was surprising that such a substance is also known as an oxidation inhibitor and again It was surprising that a substance of this type extraction or the chemical dissolution of the listed metals Can prevent machine components and also none additional particle emission and the water as well Air separation behavior did not deteriorate as well additional deposits.

The invention further consists in the use of phenoxazine, especially in an amount of 0.01 wt .-% to 0.5 wt .-%, as Inhibitor against the uptake of the metals mentioned, in particular Lead, for a lubricating oil with 80 wt .-% to 99 wt .-% with artificial and / or natural carboxylic acid esters for Machines, especially combustion machines, with third-party and / or auto ignition, hydraulic motors or the like. A Phenoxazine is also known as an antioxidant and it was quite surprising that this connection was also the Extraction of tin, copper, iron and especially lead an alloy or the chemical extraction of these metals can prevent from an alloy, further the Particle emission in the exhaust gas of an internal combustion engine due to of these substances is not increased and no additional Deposits can be caused.

In the following, the invention will be explained in more detail by means of examples explained.

COMPARATIVE EXAMPLE 1:

A synthetic carboxylic ester lubricating oil made from adipic acid edidecyl ester with 12.4% by weight of the additive package OLOA 8123 from OROGIL, Frankfurt am Main, with the following typical analytical values for the additive package: -physically Density at 15 ° C 0.979 Viscosity at 40 ° C (cSt) 1140 Viscosity at 100 ° C (cSt) 60 Flash point ° C above 180 -chemically Nitrogen weight% 0.44 Calcium weight% 1.99 Magnesium% by weight 0.61 Zinc wt% 1.04 Phosphorus% by weight 0.94 Sulfur wt% 3.30 TBN (ASTM D 2896) mg KOH / g 83 Sulfate ash% by weight 11.1 Mineral oil content% by weight 38.4 was operated in a test engine PETTER WI according to CEC L-02-A-78 as engine lubricating oil and unleaded fuel. A sample was taken from the engine lubricating oil every six hours and the content of lead, copper, tin and iron was determined using an atomic emission spectrometer in accordance with ASTM D 5185.

Example 2:

It was the experiment according to Comparative Example 1, but with an addition of 0.005% by weight of a gallic acid methyl ester carried out. There were the values given in Table I. receive.

Example 3:

It was the experiment according to Comparative Example 1, but with an addition of 0.01 wt .-% of a gallic acid methyl ester carried out. There were the values given in Table 1 receive.

Example 4:

It was the experiment according to Comparative Example 1, but with an addition of 0.05% by weight of a gallic acid methyl ester carried out. There were the values given in Table 1 receive.

Example 5:

It was the experiment according to Comparative Example 1, but with an addition of 0.1 wt .-% of a gallic acid methyl ester carried out. There were the values given in Table 1 receive.

Example 6:

It was the experiment according to Comparative Example 1, but with an addition of 0.5 wt .-% of a gallic acid methyl ester carried out. There were the values given in Table 1 receive.

Example 7:

It was the experiment according to Comparative Example 1, but with an addition of 1.0 wt .-% of a gallic acid methyl ester carried out. There were the values given in Table 1 receive.

COMPARATIVE EXAMPLE 8:

The procedure was as in Comparative Example 1, with a synthetic carboxylic ester lubricating oil based on Dioctyl adipate was used. It was the in Table 2 values obtained.

Example 9:

The procedure was as in Comparative Example 8, 0.005 % By weight gallic acid isobutyl ester was used. It the values according to Table 2 were obtained.

Example 10:

The procedure was as in Comparative Example 8, with 0.01 % By weight gallic acid isobutyl ester was used. It the values according to Table 2 were obtained.

Example 11:

The procedure was as in Comparative Example 8, 0.05 % By weight gallic acid isobutyl ester was used. It the values according to Table 2 were obtained.

Example 12:

The procedure was as in Comparative Example 8, 0.1% by weight Gallic acid isobutyl ester was used. It was the Get values according to table 2.

Example 13:

The procedure was as in Comparative Example 8, 0.5% by weight Gallic acid isobutyl ester was used. It was the Obtain values according to Table 2.

Example 14:

The procedure was as in Comparative Example 8, 1.0% by weight Gallic acid isobutyl ester was used. It was the Get values according to table 2.

COMPARATIVE EXAMPLE 15:

The procedure was as in Comparative Example 1, with a synthetic carboxylic ester lubricating oil from a complex ester Molecular weight 600 RADIALUBE from FINA, Belgium for Use. There were those listed in Table 3 Get results.

Example 16:

The procedure was as in Comparative Example 15, 0.005 % By weight of phenothiazine was used. It was the values obtained according to Table 3.

Example 17:

The procedure was as in Comparative Example 15, 0.01 % By weight of phenothiazine was used. It was the values obtained according to Table 3.

Example 18:

The procedure was as in Comparative Example 15, 0.05 % By weight of phenothiazine was used. It was the values obtained according to Table 3.

Example 19:

The procedure was as in Comparative Example 15, 0.1 % By weight of phenothiazine was used. It was the values obtained according to Table 3.

Example 20:

The procedure was as in Comparative Example 15, 0.5 % By weight of phenothiazine was used. It was the values obtained according to Table 3.

Example 21:

The procedure was as in Comparative Example 15, 1.0 % By weight of phenothiazine was used. It was the values obtained according to Table 3.

COMPARATIVE EXAMPLE 22:

A synthetic carboxylic ester lubricating oil made from dioctyl adipate was used according to comparative example 1. It the values according to Table 4 were obtained.

Example 23:

The procedure was as in Comparative Example 22, 0.005 % By weight of phenoxazine was used. It was the values obtained according to Table 4.

Example 24:

The procedure was as in Comparative Example 22, 0.01 % By weight of phenoxazine was used. It was the values obtained according to Table 4.

Example 25:

The procedure was as in Comparative Example 22, 0.05 % By weight of phenoxazine was used. It was the values obtained according to Table 4.

Example 26:

The procedure was as in Comparative Example 22, 0.1 % By weight of phenoxazine was used. It was the values obtained according to Table 4.

Example 27:

The procedure was as in Comparative Example 22, 0.5 % By weight of phenoxazine was used. It was the values obtained according to Table 4.

Example 28:

The procedure was as in Comparative Example 22, using 1.0% by weight of phenoxazine. The values according to Table 4 were obtained. Example No .: 1 2nd 3rd 4th 5 6 7 ppm lead after 6 h 10th 10th 9 - - - after 12 h 18th 18th 18th 18th 12th 11 10th after 24 h 23 21 22 18th 15 13 12th after 36 h 32 29 27 22 18th 15 14 after 66 h 64 35 35 38 40 23 14 after 96 h 95 46 40 38 40 27 14 after 126 h 132 55 46 38 40 30th 16 after 156 h 155 61 51 38 40 33 18th after 186 h 182 66 55 38 42 34 25th after 216 h 214 72 57 38 42 34 27 Example No .: 8th 9 10th 11 12th 13 14 ppm lead after 6 h 13 11 8th 8th - - - after 12 h 21 20th 17th 13 12th 14 - after 24 h 30th 28 24th 20th 21 20th 20th after 36 h 39 35 29 25th 24th 26 - after 66 h 58 51 43 31 32 31 30th after 96 h 108 90 85 39 39 38 41 after 126 h 151 122 108 45 47 44 - after 156 h 193 141 126 47 48 45 43 after 186 h 227 186 147 47 48 - - after 216 h 253 199 155 49 50 48 47 Example No .: 15 16 17th 18th 19th 20th 21 ppm lead after 6 h 9 7 8th - - - - after 12 h 14 14 12th 11 - 12th 11 after 24 h 22 20th 19th 20th - - - after 36 h 29 28 29 28 26 26 24th after 66 h 37 38 38 - - - - after 96 h 46 44 45 43 - - 47 after 126 h 58 53 55 53 51 50 51 after 156 h 69 64 64 65 - 63 63 after 186 h 76 72 70 69 - 67 65 after 216 h 89 77 75 69 66 68 67 Example No .: 22 23 24th 25th 26 27 28 ppm lead after 6 h 13 12th 12th 11 11 10th 10th after 12 h 21 23 22 20th 20th 18th 16 after 24 h 30th 30th 29 27 26 23 23 after 36 h 39 37 35 34 31 29 28 after 66 h 58 56 53 51 50 36 35 after 96 h 108 105 101 95 91 48 46 after 126 h 151 145 141 133 - 55 51 after 156 h 193 185 178 159 144 63 58 after 186 h 227 206 200 181 160 70 65 after 216 h 253 218 209 197 166 72 67

It was in both the comparative examples and in the Examples of the separation of particles in the exhaust gas charged diesel engine with charge air cooling. The Determination was made according to ECE-R-49, the improvement of Particle values for Comparative Examples 1, 8, 15 and 22 in Compared to a conventional 15W-40 engine oil were from 4% to 10%, whereas that of Examples 2 to 7, 8 to 14, 16 to 21, 23 to 28 were from 5% to 9%. From these numbers results in a clear way that by adding the Inhibitor no additional particles were caused in the exhaust gas.

When comparing the lead contents shown in Tables 1 to 4 it can be stated that the addition of 0.005% by weight of inhibitors shows a significant effect and the full effect occurs with a content of approx. 0.1% by weight and the lead absorption in the oil decreases with increasing inhibitor content. The uptake of copper, tin and iron is ensured by the Inhibitor inhibited, but the maximum is Efficacy between 0.1% and 0.5% by weight.

The engine was run after each 216 hours of test runs disassembled. Noteworthy deposits were only found in Inhibitor dosages of 1.0% by weight.

The viscosity, air separation and water absorption behavior was unchanged.

COMPARATIVE EXAMPLE 29:

A bearing metal alloy with 80.0% by weight of tin, 12.0% by weight of antimony, 6% by weight of copper and 2% by weight of lead was made in a synthetic carboxylic acid ester oil from adipic acid ditridecyl ester with 1.0% by weight. % of the additive package specified in Comparative Example 1 stored at 120 ° C. with constant stirring. The sample consisted of a circular disc with a weight of 25 g and an area of 8 cm ² , whereas the amount of oil was 200 ml. The amount reduced by sampling was replaced by the same, but unused, ester oil. The determination of the lead content was carried out according to Comparative Example 1 and the values given in Table 5 were obtained.

Example 30:

It was the experiment according to Comparative Example 29, but with an addition of 0.005% by weight of a gallic acid methyl ester carried out. There were the values given in Table 5 receive.

Example 31:

It was the experiment according to Comparative Example 29, but with an addition of 0.01 wt .-% of a gallic acid methyl ester carried out. There were the values given in Table 5 receive.

Example 32:

It was the experiment according to Comparative Example 29, but with an addition of 0.05% by weight of a gallic acid methyl ester carried out. There were the values given in Table 5 receive.

Example 33:

It was the experiment according to Comparative Example 29, but with an addition of 0.1 wt .-% of a gallic acid methyl ester carried out. There were the values given in Table 5 receive.

Example 34:

It was the experiment according to Comparative Example 29, but with an addition of 0.5 wt .-% of a gallic acid methyl ester carried out. There were the values given in Table 5 receive.

Example 35:

It was the experiment according to Comparative Example 29, but with an addition of 1.0 wt .-% of a gallic acid methyl ester carried out. There were the values given in Table 5 receive.

COMPARATIVE EXAMPLE 36:

The procedure was as in Comparative Example 29, with a synthetic carboxylic ester lubricating oil based on Dioctyl adipate was used. It was the in Values listed in Table 6 obtained.

Example 37:

The procedure was as in Comparative Example 29, 0.005 % By weight gallic acid isobutyl ester was used. It the values according to Table 6 were obtained.

Example 38:

The procedure was as in Comparative Example 29, 0.01 % By weight gallic acid isobutyl ester was used. It the values according to Table 6 were obtained.

Example 39:

The procedure was as in Comparative Example 29, 0.05 % By weight gallic acid isobutyl ester was used. It the values according to Table 6 were obtained.

Example 40:

The procedure was as in Comparative Example 29, 0.1 % By weight gallic acid isobutyl ester was used. It the values according to Table 6 were obtained.

Example 41:

The procedure was as in Comparative Example 29, 0.5 % By weight gallic acid isobutyl ester was used. It the values according to Table 6 were obtained.

Example 42:

The procedure was as in Comparative Example 29, 1.0 % By weight gallic acid isobutyl ester was used. It the values according to Table 6 were obtained.

COMPARATIVE EXAMPLE 43:

The procedure was as in Comparative Example 29, with a synthetic carboxylic ester lubricating oil from a complex ester Molecular weight 600 RADIALUBE from FINA, Belgium for Use. The values according to Table 7 receive.

Example 44:

The procedure was as in Comparative Example 43, 0.005 % By weight of phenothiazine was used. It was the values obtained according to Table 7.

Example 45:

The procedure was as in Comparative Example 43, 0.01 % By weight of phenothiazine was used. It was the values obtained according to Table 7.

Example 46:

The procedure was as in Comparative Example 43, 0.05 % By weight of phenothiazine was used. It was the values obtained according to Table 7.

Example 47:

The procedure was as in Comparative Example 43, 0.1 % By weight of phenothiazine was used. It was the values obtained according to Table 7.

Example 48:

The procedure was as in Comparative Example 43, 0.5 % By weight of phenothiazine was used. It was the values obtained according to Table 7.

Example 49:

The procedure was as in Comparative Example 43, 1.0 % By weight of phenothiazine was used. It was the values obtained according to Table 7.

COMPARATIVE EXAMPLE 50:

A synthetic carboxylic acid ester lubricant made from dioctyl adipate was used according to comparative example 29. It the values according to Table 8 were obtained.

Example 51:

The procedure was as in Comparative Example 50, 0.005 % By weight of phenoxazine was used. It was the values obtained according to Table 8.

Example 52:

The procedure was as in Comparative Example 50, 0.01 % By weight of phenoxazine was used. It was the values obtained according to Table 8.

Example 53:

The procedure was as in Comparative Example 50, 0.05 % By weight of phenoxazine was used. It was the values obtained according to Table 8.

Example 54:

The procedure was as in Comparative Example 50, 0.01 % By weight of phenoxazine was used. It was the values obtained according to Table 8.

Example 55:

The procedure was as in Comparative Example 50, 0.5 % By weight of phenoxazine was used. It was the values obtained according to Table 8.

Example 56:

The procedure was as in Comparative Example 50, using 1.0% by weight of phenoxazine. The values according to Table 8 were obtained. Example No .: 29 30th 31 32 33 34 35 ppm lead after 6 h 5 5 5 3rd 2nd 2nd 1 after 12 h - - - - - - - after 24 h 19th 16 11 9 5 5 4th after 36 h - - - - - - - after 48 h 25th 20th 20th 15 9 6 6 after 60 h - - - - - - - after 72 h 39 31 28 18th 11 6 6 after 84 h - - - - - - - after 96 h 48 39 35 29 13 7 8th Example No .: 36 37 38 39 40 41 42 ppm lead after 6 h 5 5 4th 3rd 3rd - 3rd after 12 h - - - - - - - after 24 h 22 21 21 20th 16 - 11 after 36 h - - - - - - - after 48 h 31 31 30th 30th 24th 21 20th after 60 h - - - - - - - after 72 h 44 45 43 - 35 31 26 after 84 h - - - - - - - after 96 h 53 55 52 48 41 39 32 Example No .: 43 44 45 46 47 48 49 ppm lead after 6 h 3rd 3rd 2nd <1 <1 <1 <1 after 12 h - - - - - - - after 24 h 17th 15 11 8th 5 3rd 3rd after 36 h - - - - - - - after 48 h 22 21 20th 16 9 5 3rd after 60 h - - - - - - - after 72 h 28 25th 21 18th 12th 6 4th after 84 h - - - - - - - after 96 h 31 27 25th 21 14 6 4th Example No .: 50 51 52 53 54 55 56 ppm lead after 6 h 7 7 5 5 3rd <1 <1 after 12 h - - - - - - - after 24 h 20th 20th 18th 16 14 10th 8th after 36 h - - - - - - - after 48 h 28 26 23 21 18th 15 12th after 60 h - - - - - - - after 72 h 35 31 28 25th 23 20th 18th after 84 h - - - - - - - after 96 h 43 40 38 33 29 24th 22

As the values in Tables 5 to 8 show, the Adding the inhibitors significantly reduced the To achieve lead content in the ester oil. Such oils are for example for hydraulic units, such as gear pumps, vane pumps u. Excellent. Despite the high The content of additives could not be found during the stirring process Inclusion of air, such as in the form of small ones Bubbles or the like can be observed. The samples used after 96 hours showed no cloudiness due to a covering or Like. So that no deposits formed are. The viscosity and water absorption behavior of the fresh oils was unchanged.

Claims (7)

Lubricating oil for machines, especially for internal combustion engines, with spark and / or auto ignition, hydraulic Motors or the like. With a content of 80 wt .-% to 99% by weight of artificial and / or natural carboxylic acid esters, an additive to improve the viscosity behavior, Antioxidants, especially based on sterically hindered Phenols and amines, anti-foaming agents, detergents, dispersants, Demulsifiers, corrosion inhibitors, wear protection, characterized in that there is an addition of preferably 0.01% to 0.5% by weight of an inhibitor against chemical extraction and / or extraction of tin, Copper and iron, especially lead from alloys, preferably bearing alloys and cage alloys. Lubricating oil according to claim 1, characterized in that the additive has a gallic acid ester of the following formula or consists thereof

where R is a methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, octyl and dodecyl radical. Lubricating oil according to claim 1 or 2, characterized in that the additive has or consists of phenothiazine. Lubricating oil according to claim 1, 2 or 3, characterized in that that the additive has or consists of phenoxazine. Use of a gallic acid ester with the following general composition

where R is a methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, octyl and dodecyl radical, in particular in an amount of 0.01% by weight to 0.5 % By weight, as an inhibitor against tin, copper and iron, in particular lead absorption for a lubricating oil with 80% by weight to 99% by weight with artificial and / or natural carboxylic acid esters for machines, in particular internal combustion engines Spark and / or auto ignition, hydraulic motors or the like. Use of a phenothiazine, especially in an amount from 0.01% by weight to 0.5% by weight, as an inhibitor against lead absorption for a lubricating oil with 80 wt .-% to 99 wt .-% with artificial and / or natural carboxylic acid esters for Machines, especially combustion machines, with third-party and / or auto ignition, hydraulic motors or the like. Use of a phenoxazine, especially in an amount from 0.01% by weight to 0.5% by weight, as an inhibitor against Lead intake for a lubricating oil with 80 wt.% To 99 wt.% with artificial and / or natural carboxylic acid esters for Machines, especially combustion machines, with third-party and / or auto ignition, hydraulic motors or the like.