EP0892038B1 - Grease composition, process for their preparation and their use - Google Patents

Description

The invention relates to a grease composition, a method for its Manufacturing and their use.

Lubricants are widely used. You will e.g. in vehicle technology, conveyor technology, mechanical engineering, office technology, industrial Plant and machinery, household machines and entertainment technology applied.

The development of new lubricants must go with the general evolution the technology go hand in hand with new and more extensive requirements Grease compositions. These are the known requirements Lubricants based on mineral or synthetic oils no longer grow.

One of the most important parameters of a grease is the grease service life at the upper service temperature. A high grease service life (= long running time) expresses a high level of wear protection. For the high temperature of 180 ° C, the F ₅₀ value, which is determined in accordance with DIN 51821, must be greater than 100 hours, it being desirable to exceed this value as clearly as possible. This has not been achieved satisfactorily by the previous grease compositions. Such greases are described, for example, in WO 90/15125 and DE 2357199. The latter describes lubricants based on triesters of phosphorothionic acid. In contrast, WO 90/15125 describes a lubricating grease composition which has a base oil and a polyharuate thickener, the base oil being an ester of an aromatic di-, tri- or tetracarboxylic acid.

The object of the invention was to provide a grease composition, which have a long grease service life and high wear protection having.

According to the invention, this problem is solved in that a grease composition, comprising an oil or oil mixture, a thickener and a wear-protecting additive is provided.

The oil or the oil mixture comprises one or more esters of aromatic tri- or tetracarboxylic acids, such as trimellitic acid or pyromellitic acid, with an alcohol or a mixture of alcohols of the general composition C _n H _{2n + 1} OH with n = 7 to 22 and / or one or more esters of trimethylolpropane, pentaerytritol or dipentaerytritol with aliphatic carboxylic acids of the general composition C _n H _{2n + 1} COOH with n = 6 to 21. Trimellitic acid tri (tridecyl) ester or pyromellitic acid tetra (2-ethyl! -hexyl) is preferred ) ester used.

The thickener comprises a di- and / or polyurea. This is the reaction product of a diisocyanate, preferably 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene, 4,4'-4,4'-diisocyanatodiphenylmethane, 4,4'-diisocyanatodiphenyl, 4,4'-diisocyanato-3 , 3'-dimethylphenyl, 4,4'-diisocyanato-3,3'-dimethyldiphenylmethane, individually or in a mixture with an amine or a mixture of amines of the general formula (H ₂ N) _x R, where R is at x = 1 Is alkyl or alkylene with 6 to 22 carbon atoms or an aryl with 6 to 12 carbon atoms and when x = 2 is an alkyl with 2 to 6 carbon atoms or an aryl with 6 to 14 carbon atoms. 2,4-Toluidine-N, N'-dicyclohexyl-diurea or N, N'-dicyclohexyl-N ", N"'(4,4'-diphenylmethane) diurea is preferably used.

The wear-protecting additive comprises a mixture of the components triaryl phosphorothionate, Alkyl (C 8-20) amino (mono, di) hexyl phosphate and alkyl (C 1-8) amino iso-butyl phosphate. Preferred are Tri-4-methylphenyl phosphorothionate, prim dodecylammonium dihexyl phosphate and prim hexylammonium diisobutyl phosphate.

The grease composition according to the invention preferably has 70 to 90% by weight of the oil or oil mixture, 5 to 29% by weight of the thickener and 1 to 5% by weight of the wear-protecting additive, based in each case on the grease composition. The wear protective additive can range from 10 to 40% by weight triaryl phosphorothionate, 5 to 30% by weight alkyl (C 8-20) amino (mono, di) hexyl phosphate and 20 to 60 wt .-% alkyl (C 1-8) amino-iso-butyl phosphate included, each based on the wear-protecting additive.

When determining the upper service temperature of 180 ° C. of the grease compositions according to DIN 51821 according to the invention using a FAG FE-9 testing machine, run times L ₁₀ > 300 hours and L ₅₀ > 400 hours are achieved.

The grease composition according to the invention has a service temperature range from -50 to 200 ° C.

In addition, the grease compositions according to the invention Common additives against corrosion, oxidation and protection against metal influences contain as radical scavengers, chelate compounds, UV converters, Reaction layer formers and the like act.

The grease compositions according to the invention are obtained by that the components of the wear-resistant additive with one part of the oil or oil mixture mixed below 80 ° C, then to a mixture the thickener with the remaining oil or oil mixture and then with a high-pressure homogenizer and / or a three-chair roller be homogenized. The part of the oil or oil mixture that is used to protect against wear Addition is added, is preferably 3 to 10 wt .-%, based on the grease composition. The rest of the oil or Oil mixture of the grease composition is reduced by this amount.

Due to the presence of the above wear-protecting additive, an unexpectedly high level of wear protection is achieved due to the grease composition. This manifests itself in the fact that when determining the upper service temperature using a FAG FE-9 testing machine in accordance with DIN 51821, extremely long running times of F ₁₀ > 300 hours and F ₅₀ > 400 hours are achieved. The required value for F ₅₀ of more than 100 hours is thus clearly exceeded.

The grease composition according to the invention is therefore very suitable as a lubricant in vehicle technology, conveyor technology, mechanical engineering, of office technology, industrial plants and machines, household machines, and of entertainment technology.

Fig. 1:

Schmierfettgebrauchsdauer einer erfindungsgemäßen Schmierfettzusammensetzung gemäß Beispiel 1

Fig. 2:

Schmierfettgebrauchsdauereinerhandelsüblichen Schmierfettzusammensetzung

Fig. 3:

zeigt einen 12-fach Prüfstand zur AL-Lebensdauererprobung (Dauerlauf) mit einem Tellerfederpaket 1, einem Prüfling 2, einer Umlufttemperatur 3, einer Temperatur am Außenring 4, einem Elektromotor 5 und einer Heizung 6.

Brief description of the figure:

Fig. 1:

Grease service life of a grease composition according to the invention according to Example 1

Fig. 2:

Grease service life of a commercially available grease composition

Fig. 3:

shows a 12-fold test stand for AL service life testing (endurance test) with a plate spring assembly 1, a test specimen 2, a circulating air temperature 3, a temperature on the outer ring 4, an electric motor 5 and a heater 6.

The invention is now illustrated by the following examples;

Examples Example 1 (B1)

In 700 g of a trimellitic acid ester (trimellitic acid tri (tridecyl) ester) 1C8.7 g of a mixture of 2,4- and 2,6-tolylene diisocyanate with 116.2 g of phenitidine implemented. The mixture was heated to 180 ° C and then cooled. At a brewing temperature of less than 80 ° C then 128 g of a mixture from 11.2 g of tri-4-methylphenyl phosphorothionate, 8.4 g of primary dodecylammonium dihexyl phosphate, 8.4 g of primary hexylammonium diisobutyl phosphate and 100 g Trimellitic acid tri (tridecyl) ester added. After homogenization Using a three-chair roller, a grease of NLGI class 2 was added particularly long running time on the FAG FE-9 testing machine at one temperature obtained from 180 ° C. The grease service life of the invention The composition and the test parameters can be seen in FIG. 1. For comparison, a commercially available grease composition, as described in WO 90/15125, tested under the same test conditions. These results are shown in Fig. 2 shown. It can clearly be seen that the composition according to the invention Regarding the grease service life is many times better.

Example 2 (B2)

In 600 g of a pyromellitic acid ester (pyromellitic acid tetra (2-ethyl-hexyl) ester) became 90.5 g of a mixture of 2,4- and 2,6-tolylene diisocyanate with 102.4 g Cyclohexylamine implemented. The mixture was heated to 180 ° C and then cooled down. Then at a brewing temperature of less than 80 ° C 135 g of a mixture of 3.5 g of tri-4-methylphenyl phosphorothionate, 10.5 g prim dodecylammonium dihexyl phosphate, 21 g prim hexylammonium diisobutyl phosphate and 100 g pyromellitic acid ester (pyromellitic acid tetra (2-ethyl-hexyl) ester) added. After homogenization using a high pressure homogenizer a grease of NLGI class 2 with a particularly long service life the FAG FE-9 testing machine at a temperature of 180 ° C.

Fax = 2000 N

n = 6000 U/min

T = 120°C.

A clutch release bearing was subjected to a continuous load test using the grease compositions according to the invention in a test stand, the structure of which is shown in FIG. 3. The following conditions apply:

Fax = 2000 N

n = 6000 rpm

T = 120 ° C.

The criterion for the assessment of the lubricant was the complete failure of the test warehouse. By using the grease composition according to the invention was the runtime of the clutch release bearing in a specification run increased from 1200 to 2000 hours. This means that especially in High temperature range from 140 to 180 ° C in the border or mixed friction area a significant increase in performance could be achieved.

Claims (8)

1. Grease composition comprising:

   (a) an oil or an oil mixture of one or more of the ester(s) of aromatic tricarboxylic or tetracarboxylic acids with an alcohol or a mixture of alcohols of the general composition C_nH_2n+1OH where n = 7 to 22 and/or one or more of the ester(s) of trimethylol propane, pe itaerythritol or dipentaerythritol with aliphatic carboxylic acids of the general composition C_nH_2n+1COOH where n = 6 to 21,

   (b) a thickening agent comprising a diurea and/or polyurea, and

   (c) a wear-protecting additive, comprising a mixture of the components triaryl phosphorothionate, alkyl(C 8-20)amino (mono, di)-hexyl phosphate and alkyl(C 1-8)amino-iso-butyl phosphate.
2. Grease composition according to claim 1, characterised in that it has 70 to 90 wt.% of the oil or oil mixture (a), 5 to 29 wt.% of the thickening agent (b) and 1 to 5 wt.% of the additive (c), in each case based on the grease composition.
3. Grease composition according to one of claims 1 or 2, ciaracterised in that the additive (c) comprises 10 to 40 wt.% of triaryl phosphorothionate, 5 to 30 wt.% of alkyl(C 8-20)amino (mono, di)-hexyl phosphate and 20 to 60 wt.% of alkyl(C 1-8)amino-iso-butyl phosphate, in each case based on the additive (c).
4. Grease composition according to one of claims 1 to 3, characterised in that when determining the upper working temperature of 180'C according to DIN 51 821 by means of a FAG FE-9 test machine, operating times L₁₀ > 300 hours and L₅₀ > 400 hours are achieved.
5. Grease composition according to one of claims 1 to 4, characterised in that it has a working temperature range from -50 to 200°C.
6. Process for producing a grease composition according to one of claims 1 to 5, characterised in that the components of the additive (c) are mixed with a part of the oil or the oil mixture (a) below 80°C, then added to a mixture of the thickening agent (b) with the remaining oil or oil mixture (a) and then homogenised.
7. Process according to claim 6, characterised in that the part of the oil or oil mixture (a) to be mixed with the additive (c) is 3 to 10 wt.%o, based on the grease composition.
8. Use of the grease composition according to one of claims 1 to 5 as lubricant in vehicle technology, materials-handling technology, machine construction, office technology, industrial plants and machines, household machines and maintenance technology.

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