DE1644861B - Synthetic lubricants - Google Patents

Description

The invention relates to synthetic lubricants, their wear and corrosion resistance properties by adding small amounts of certain additives are improved.

The use of certain acidic phosphorus compounds to increase the load capacity and wear resistance as additives for synthetic lubricating oils had been suggested earlier, but it was associated with a number of disadvantages. For example, lubricating oils have a tendency to be corrosive to be when in the earlier preferred concentrations and at the extremely high temperatures, which lubricants for modern aircraft engines must withstand, are used. It has demonstrated that some of them are incompatible with metal passivators that are added to the lubricant with regard to its corrosiveness towards metals and especially copper improve.

It has now been found that by using a combination of certain amounts certain dialkyl hydrogen phosphates and metal passivators are possible synthetic lubricants produce the very good wear and corrosion resistance properties at very high temperatures to have. In certain cases, products can be obtained by adding suitable antioxidants to these mixtures with the properties required to lubricate the engines of modern supersonic jet aircraft produce.

The lubricants according to the invention based on synthetic lubricating oils consist of

a formula

(R ² O) ₃ PO,

in which R ^{2 are} alkyl, cycloalkyl, aryl, alkaryl or aralkyl groups with a total number of 3 to 60, preferably up to 10 carbon atoms in the molecule.

The concentrations given in this description the additives are based on the ester. Of course, the mixture can do more as one element of each group of said constituents.

Copper passivators are well known materials

which function to reduce the extent to which corrosive substances attack copper. The Copper passivating agents used in the mixtures according to the invention must of course be in the Base oil can be soluble. This means has the purpose

This is the case with the corrosion of the materials used in engine parts reduce if this prolonged time at high temperatures and in the presence of air the lubricant are exposed. The effectiveness of metal passivants can be checked by corrosion

»5 hung measure, through which the protection of metallic Share shows. In such tests, copper is the most critical metal to be found it has been shown that with an effective passivation of this metal the corrosion of the others used Metals is negligibly low. The exception here is lead. Among the appropriate groups of Copper passivators include:

1. a base oil of one or more neutral liquid polyesters are prepared by reacting under esterification conditions and in one or sev- eral ^3S steps

a) a mono- or polyhydric alcohol having 5 to 15, preferably 5 to 10 carbon atoms per molecule, with no hydrogen atom attached to a carbon atom in the 2-position is bound to an - OH group, and

b) a mono- and / or polycarboxylic acid having 2 to 14, preferably 3 to 12 carbon atoms per molecule, * 5

2. 0.005 to 0.15 percent by weight, preferably less than 0.08 percent by weight, of a dihydrocarbon hydrogen phosphate of the general formula _So

(RO) ₂ P (O) OH,

in which R is alkyl, cycloalkyl, aryl, alkaryl or aralkyl groups with up to 20 carbon atoms and preferably alkyl or cycloalkyl groups of up to 10 carbon atoms, such as Butyl, 2-ethylhexyl or cyclohexyl,

3. 0.005 to 1.5 percent by weight, preferably 0.01 to 0.5 percent by weight, of a copper passivator,

4. 0.5 to 6.0, preferably 2.5 to 5 percent by weight of an aromatic amine as an antioxidant, possibly off

5. 0.01 to 1 percent by weight of a lead corrosion inhibitor and optionally off

6. 0.01 to 10, preferably 0.5 to 5.0 percent by weight of a neutral phosphate of the general

1. those of the azoles, such as imidazole, pyrazole, triazole and their derivatives, e.g. B. Benzotriazole, Metbylbenzotriazole, ethylbenzotriazole, butylbenzotriazole, dodecylbenzotriazole, methylene-bis-benzotriazole and naphthotriazole;

2. Salicylaldehyde semicarbazone and its C ₁ - to C _ao -alkyl derivatives, e.g. B. methyl and isopropyl salicylaldehyde semicarbazone;

3. Condensation products of salicylaldehyde and hydrazine derivatives and fatty acid salts of such Condensation products. A particularly suitable hydrazine derivative is aminoguanidine, while as fatty acids those with 2 to 24 carbon atoms are suitable.

Particularly effective copper passivating agents are methylene-bis-benzotriazole and the salts of 1-salicylalaminoguanidine and fatty acids having 13 to 18 carbon atoms, such as palmitic acid. If the lubricant mixture is intended for use in engines with components made of lead alloys, it is desirable to add a lead corrosion inhibitor to the mixture, generally in a concentration of 0.01 to 1.0, preferably 0.05 to 0.25 percent by weight. Suitable lead corrosion _{inhibitors are C 1} - to C ₂₀ -alkyl gallic acid esters (for example propyl gallate), neopentyl glycol disebacic acid esters, sebacic acid and quinizarine. Propyl gallate is preferred; it does not affect the other properties of the lubricant.

Suitable aromatic amines to be used as antioxidants include phenothiazine, iminodibenzyl, diphenylamine, phenyl - * - naphthylamine and phenyl-jS-naphthylamine. The alkylated (e.g. C ₁ - to C ₁₄ -alkylated) aromatic

3 4

see amines and especially those make up the formula. Preferred neutral phosphates are pir Hxiur u Di those in which R ^{2 is} alkyl or cycloalkyl groups κ ^ _e n ₄ iNti ^ _e ti ₄ K, _{with up to 10} carbon atoms, for example where R ^{1 is} alkyl groups with up to 14 carbon phenyl -, tolyl or xylyl groups,
atoms (not necessarily in any given molecule 5 R ^- I
same) and in particular octyl or nonyl groups examples
are. ρ, ρ'-dioctyldiphenylaniine is particularly effective. A number of lubricants according to the invention and other particularly suitable alkylated aromatic and a number of comparative _{mixtures have been tested for amines are the mono- and di-C 1} - to C ₁₄ -alkyl, wear or pressure absorption properties (e.g. dioctyl and dinonyl) Phenothiazines, iminoxes using the well-known IAE gear dibenzyls, diphenyl-p-phenylenediamines and phenyl machines as well as anti-corrosion properties and naphthylamines. In certain cases it may be desirable to have high temperature resistance to oxidation using a mixture of antioxidants, e.g. B. a part of an oxidation-corrosion test mixed with an alkylated diphenylamine (e.g. diabetes. The tests corresponded to the official octyldiphenylaniin) and an alkylated phenyl- 15 specifications and those of the manufacturers of trjebnaphthylamine (e.g. . to use a mono-octylphenylnaphthyl plant for lubricants for use in Triebamin). works for modern jet aircraft.

As used in this specification, the gear test became the test

“Polyester” means an ester with at least two lubricants at a temperature of 20O ⁰ C

Ester bonds per molecule. The term "neutral" means a set of gears running at one speed

stands for a fully esterified product. Of course, they were driven by 2000 revolutions per minute,

Lent can be sprayed on with the aforementioned esterification, while using a loaded lever arm

reaction more than one of the mentioned reaction force was applied. As soon as the

components are used, for example a gear wheel occurred, the effect on the lever arm was

Mixture of monocarboxylic acids, with the increasing load being registered.

neutral ester product of the esterification reaction up to that carried out under high temperature

because the oil was selected from a mixture of different ester moles- oxidation-corrosion test

so that the expression "polyester" takes 48 hours in the presence of five metals and

is to be interpreted from this point of view. with an air stream of

Polyesters which, in the mixture according to the invention, ^{hold ge base oils as 30 5 liters / hour at a temperature of 218 °} C. particularly suitable for high temperatures. The metal weight changes, as well as the amount of time, are those from the following acids and alcohols, the viscosity and acid value of the oil increased products made: caprylic acid, capric acid, measured. The purity of the oil was determined in the context of caproic acid, enanthic acid, pelargonic acid, valerian acid - this test by measuring the amount of insoluble material formed, pivalic acid, propionic acid, butyric acid, 2-ethyl- 35, caproic acid, adipic acid, sebacic acid, azelaic acid. For the lubricant mixtures tested, acid, 2,2,4-trimethylpentanol, neopentyl alcohol and the following base oils were used:

Neopentylglycol trimethylolethane Trimethylolpro- _{A A coraplex ester of the reaction of}

pan, pentaerythnt and dipentaerythnt, caprylic acid, 1,1,1-trimethylolpropane and Se-

Examples of _{such particularly suitable polyester md : 40 bac} y acid in a molecular ratio of 28: 10: 1

(a) Esters of trimethylolpropane, trimethylolethane, under esterification conditions and under ver-pentaerythritol and / or dipentaerythritol with one turn of a catalyst, or several monocarboxylic acids with 3 to 10 β A mixture of 4 parts by weight of a neutral carbon atoms, in particular those in the above Esters of pentaerythritol and a mixture of the type described in the paragraph, and ⁴⁵ straight-chain Cs-C ^ monocarboxylic acids with one

(b) Complex esters from trimethylolpropane, sebacin weight fraction of a neutral ester from diacid and / or azelaic acid and one or pentaerythritol and the same mixture of several monocarboxylic acids with 3 to 10 carboxylic acids.

Carbon atoms, especially of the _{kind described in the Mixtures section} above. It is best to use *
Trimethylolpropane and dicarboxylic acid in a molar ratio of 1: 0.05 to 0.75, preferably of DBHP = dibutyl hydrogen phosphate:
1: 0.075 to 0.4, reacted to give (C ₄ H ₉ O) ₂ P (O) OH.
The amount of monocarboxylic acid is sufficient to trigger a SAGP = salt of l-salicylaldehyde aminoguanidine carboxyl-hydroxyl equilibrium in the reactants and a mixture of fatty acids with active agents. 13 to 18 carbon atoms.

~. ,,.,. ". ,. . .., _Λ,, . _v MBBTZ - methylene-bis-benzotriazole.
The good wear resistance and resilience

Properties of the lubricants according to the invention antioxidants:

can be improved by adding a neutral phosphate 60. In all cases, the formula (R ² O) ₃ PO was improved even further, with a mixture of 3 parts of p, p'-di-R ⁴ alkyl, cycloalkyl, Aryl, alkaryl or aralkyl octyldiphenylamine and 1 part are monooctyl groups (which are not necessarily in any given phenyl-ß-naphthylamine. This has to be the same as a molecule) and the total number being the best combination in terms of purely carbon atoms in the molecule 3 to 60 , Preference 65 for both long and short periods is 3 to 30. The proportion of such oxidation tests proved
neutral phosphorus compound should be 0.01 to 10, TTP = tritolyl phosphate.
preferably 0.5 to 5 percent by weight of the mixture PG = propyl gallate.

5

The lubricant mixtures used in the tests are shown in Tables 1 and 2.

The numbers are based on parts by weight.

Table 1 Composition of mixtures according to the invention

1 2 Z
¹ X composition
4 I 5 100
0.02
0.02
4.0
2.0 6th 7th Base oil A 100
0.02
0.1
4.0 100
0.02
0.1
4.0
0.1 100
0.02
0.1
4.0
2.0
0.1 100
0.02
0.02
4.0
2.0
0.1 100
0.02
0.1
4.0
0.1 Grondöl B 100
0.02
0.1 DBHP 4.0
2.0
0.1 SAGP MBBTZ ... Antioxidants ..
TTP PG

Table 2 Composition of the comparative mixtures

21 22nd 23 Put together!
24 I 25 lOO ng
26th 27 28 29 Base oil A 100 100 lOO 100 Base oil B 0.02 100 100 100 100 DBHP 4.0
2.0
0.1 0.02 SAGP 0.1
4.0
0.1 4.0
2.0 4.0
2.0
0.1 0.1
4.0
2.0
0.1 0.1
4.0
0.1 4.0
2.0
0.1 0.1
4.0
2.0
0.1 Antioxidants ..
TTP 4.0
2.0
0.1 PG

The results of the tests are recorded in Tables 3, 4 and 5.

Table 3 Load capacity and pressure capacity test

composition Eating load
kg 21 16.8 1 29.5 2 28.1 24 16.3 3 36.3 26th 18.6 6th 24.9 28 20.0 7th 29.5

The superior pressure absorption properties of the mixtures according to the invention with low The proportions of dibutyl hydrogen phosphate compared to the other mixtures can be clearly seen.

Table 4 Oxidation-Corrosion Test

Viscosity acid Mg Metal weight change Al mg / cm ^s Desirable limits + 0.3 to-0.3 Ag Fe -0.13 -0.03 ..., increase in increase Cu + 0.3 to-0.3 -0.01 -0.05 -0.1 Fabrics Together 37.8 ^U C in% mgKOH / g -0.03 none + O, 3bis-O, 3 | + O, 3bis-O, 3 | - »- O.3bis-O, 3 -0.13 -0.03 in mg settlement -0.02 -0.01 -1.14 -0.12 -0.04 max. 50 max. 5 -0.03 -0.03 -0.75 -0.06 +0.01 0 22nd 45 1.7 -0.04 -0.01 -1.14 -0.05 +0.06 0 23 53 3.5 none +0.02 -0.07 -0.03 +0.04 0 25th 44 3.6 none +0.3 -0.09 -0.11 -0.03 0 2 35 1.3 none -0.06 +0.02 -0.10 none 0 3 40 2.5 none -0.01 none -0.12 -0.01 0 4th 38 2.2 -0.05 -0.04 -1.81 -0.13 -1-0.03 0 5 36 3.0 none -0.02 -0.89 0 27 64 1.7 -0.03 -0.12 0 29 56 i 1.8 -0.15 0 6th 36.5 0.5 0 7th 45 1.7

The results listed in Table 4 show the extraordinarily high oxidation and corrosion levels ion resistance and the outstanding purity of the lubricants according to the invention.

Mixtures 2 to 7 gave far better results in these tests than mixtures 22, 23, 25, 27 and 29 that did not contain a copper passivator. The following Table 5 shows that the by Addition of small amounts of dibutyl hydrogen phosphate achieved a substantial improvement in the load capacity without any noticeable impairment of the oxidation-corrosion properties of the mixtures in front of them goes.

mixture Eating load
kg Viscosity
increase in
37.8 ° C in "U Acidity increase
mgKOH / g Mg metal
Al weight change
mg / cm ²
Cu eration
Ag Fc Insoluble
Fabrics
in mg 2
21 28.1
16.8 I.
35
39 1.3
2.7 -0.04
-0.02 -0.03
-0.03 -0.07
-0.09 -0.12
-0.06 -0.04
-0.03 0
0 3
24 36.3
16.3 41.7
40 4.8
2.5 -0.06
none -0.06
-0.01 -0.12
-0.09 -0.09
-0.06 none
+0.01 0
0 6th
26th 24.9
18.6 36.5
38 0.5
1.25 none
+0.01 -0.04
none -0.12
-0.11 -0.12
-0.03 -0.01
none 0
0 7th
28 29.5
20.0 45
38 1.7
3.3 -0.03
-0.05 -0.02
-0.02 -0.15
-0.09 -0.13
-0.08 +0.03
-0.02 0
0

Claims (6)

Patent claims: 1. Lubricant based on synthetic lubricating oils, consisting of 1. a base oil made from one or more liquid neutral polyesters that are produced by Reaction has been produced in one or more stages under esterification conditions are made a) a monohydric or polyhydric alcohol having 5 to 15 carbon atoms per molecule, no hydrogen atom being bonded to a carbon atom in the 2-position to form an —OH group, and S ₅ b) a mono- and / or polycarboxylic acid with 2 to 14 carbon atoms per molecule, ; 2. 0.005 to 0.15 percent by weight of a dihydrocarbon hydrogen phosphate the general formula (RO) ₂ P (O) OH, in which R is alkyl, cycloalkyl, aryl, alkaryl or aralkyl groups with up to 20 carbon atoms are, 3. 0.005 to 1.5 percent by weight of a copper passivator and 4. 0.5 to 6.0 percent by weight of an aromatic amine as an antioxidant, if necessary 5. 0.01 to 1 percent by weight of a lead corrosion inhibitor and optionally off 109525/335 6. 0.01. to 10, preferably 0.5 to 5.0 percent by weight of a neutral phosphate of the general formula (R ² O) ₃ PO, in which R ^{2 are} alkyl, cycloalkyl, aryl, alkaryl or aralkyl groups with a total number of 3 to 60, preferably up to 10 carbon atoms in the molecule. 2. Lubricant according to claim 1, characterized in that it consists of an ester as a polyester Trhnetbylolpropane, trimethylolethane, pentaerythritol and / or dipentaerythritol and one or more monocarboxylic acids with 3 to 10 carbon atoms contains. 3. Lubricant according to claim 1, characterized in that it is a complex polyester Esters of trimethylolpropane, sebacic acid and / or azelaic acid and one or more monocarboxylic acids contains 3 to 10 carbon atoms. 4. Lubricant according to Claims 1 to 3, characterized in that it is a component 2 a dicohydrocarbon hydrogen phosphate of the general common formula (RO) ₂ P (O) OH, in which R is alkyl or cycloalkyl groups of up to 10 carbon atoms, the Amount of phosphate is between 0.005 and 0.08 percent by weight. 5. Lubricant according to claims 1 to 4, characterized in that it is used as a copper passivator Methylene-bis-benzotriazole or a salt from 1-salicylaldehyde aminoguanide and one or contains several fatty acids with 13 to 18 carbon atoms, the amount of copper passivator is between 0.01 and 0.5 percent by weight. 6. Lubricant according to claims 1 to 5, characterized in that it is used as an antioxidant an alkylated aromatic amine of the general formula R ¹ C ₆ H ₁₁ NHC ₆ H ₄ R ¹ , in which R ^{1 are} alkyl groups with up to 14 carbon atoms, optionally in a mixture with a mono- or di-C ₁ - to C ₁₄ -alkylphenylnaphthylamine.