EP3372659B1 - High temperature lubricants - Google Patents

Description

The invention relates to high-temperature lubricants, in particular greases based on an aromatic ester, such as a trimellitic acid ester and mixtures of different trimellitic acid esters and a fully hydrogenated or hydrogenated polyisobutylene or a mixture thereof, a thickener. The invention also relates to the use of this high-temperature grease for continuous use temperatures of up to 250 ° C.

In addition to the lubricating effect, the lubricants have to fulfill a number of other tasks: They have to cool, reduce friction, wear and power transmission, protect against corrosion and at the same time have a sealing effect. In addition, the high-temperature greases should be quiet.

Conventional lubricants are not suitable for high-temperature applications because they are destroyed at high temperatures, for example via oxidation and / or thermal decomposition reactions and polymerizations, and their lubricating properties are severely restricted. During decomposition reactions, the lubricant is split into low-molecular volatile components. Their evaporation leads to undesirable changes in viscosity, loss of oil and excessive vapor formation. This results in a loss of the lubricating effect. The lubricants also lose their lubricating effect through polymerization due to the formation of insoluble polymerization products.

Removing this contamination increases maintenance work and produces chemical waste that is laborious to dispose of. Due to the increased cleaning and maintenance work, the Downtime. Overall, the use of unsuitable lubricants in high-temperature applications leads to higher costs, since the tools become dirty and there is a higher demand for lubricants. In addition, the product quality decreases.

Synthetic esters are often used as base oils for high-temperature applications because they have very good oxidative, hydrolytic and thermal stability.

In order to meet the diverse requirements of high-temperature applications, the lubricants must have, among other things, high stability, low coefficients of friction and high wear resistance. In order to be able to guarantee uniform lubrication even at high temperatures, a liquid lubricating film must remain between metal parts during the entire processing process. For this reason, the lubricant must only evaporate a little at the maximum processing temperature, form few residues and form as few cracking residues as possible.

High temperatures often occur when used in chains, roller and plain bearings, in vehicle technology, conveyor technology, mechanical engineering, office technology and in industrial systems and machines, but also in the areas of household machines and entertainment electronics.

In roller and plain bearings, lubricants ensure that a separating, load-transferring lubricating film is built up between parts sliding or rolling on each other. This ensures that the metallic surfaces do not touch each other and therefore no wear occurs. The lubricants must therefore meet high requirements. These include extreme operating conditions such as very high or very low speeds, high temperatures caused by high speeds or external heating, very low temperatures, for example with bearings that work in a cold environment or that are used in the air and Space travel occur. Modern lubricants should also be able to be used under so-called clean room conditions in order to avoid room pollution from abrasion or consumption to avoid using lubricants. In addition, when using modern lubricants, it should be avoided that they evaporate and thus "clog", ie that they become solid after a short application and no longer show any lubricating effect. Special requirements are also placed on lubricants when they are used in such a way that the running surfaces of the bearings are not attacked by low friction, the bearing surfaces run quietly, and long running times are achieved without relubrication. Lubricants also have to withstand the effects of forces such as centrifugal force, gravity and vibrations.

• GNX: etwas schlechter als GN1 (sehr schlechtes Geräuschverhalten)
• GN1: >95% aller Peaks sind <=40 µm/s (schlechtes Geräuschverhalten)
• GN2: >95% aller Peaks sind <=20 µm/s; > 98% aller Peaks sind <= 40 µm/s (mittleres Geräuschverhalten)
• GN3: >95% aller Peaks sind <=10 µm/s; > 98% aller Peaks sind <= 20 µm/s; > 100% aller Peaks sind <= 40 µm/s (gutes Geräuschverhalten)
• GN4: >95% aller Peaks sind <= 5 µm/s; > 98% aller Peaks sind <= 10 µm/s; > 100% aller Peaks sind <= 20 µm/s (sehr gutes Geräuschverhalten)

An important parameter for a long service life of a grease-lubricated roller bearing in the high temperature range is, in addition to the upper service temperature, the noise behavior of the lubricant. A lubricating grease can stimulate vibrations in the rolling bearing when it participates in circulation (rolling over, flexing), which are "lubricant noises" in the medium 300 to 1,800 Hz and high 1,800 to 10,000 Hz frequency bands, compared to the bearing noise in the low frequency band at 50 to 300 Hz. The lubricant noise is superimposed by the noise peaks that occur when hard particles roll over the rolling elements in the form of shock pulses on the bearing ring. The evaluation of the noise behavior is based on the SKF BeQuiet ⁺ method.

• GNX: slightly worse than GN1 (very poor noise behavior)
• GN1: > 95% of all peaks are <= 40 µm / s (poor noise behavior)
• GN2: > 95% of all peaks are <= 20 µm / s; > 98% of all peaks are <= 40 µm / s (average noise behavior)
• GN3: > 95% of all peaks are <= 10 µm / s; > 98% of all peaks are <= 20 µm / s; > 100% of all peaks are <= 40 µm / s (good noise behavior)
• GN4: > 95% of all peaks are <= 5 µm / s; > 98% of all peaks are <= 10 µm / s; > 100% of all peaks are <= 20 µm / s (very good noise behavior)

The better the noise behavior of a lubricating grease, the lower the vibrations of the bearing caused by the lubricant. This is equivalent to a low load on the bearing and leads to a longer service life of storage.

The object of the present invention is to provide a high-temperature grease which meets the above-mentioned requirements. In particular, the lubricating oil or grease should show a good lubricating effect at high temperature over a long period of time. Furthermore, the cracking residues formed should not be laked up, but should be able to be dissolved again by fresh fat. Furthermore, the high-temperature lubricant should have good hydrolytic stability, be corrosion- and wear-resistant, as well as good oxidation resistance and good low-temperature behavior adapted to the requirements. This is defined for lubricating oils by the pour point and for lubricating greases by the flow pressure at low temperatures. In addition, the high-temperature grease should exhibit good noise behavior, have long running times and essentially cause no signs of wear on the devices.

It's from the EP 0 892 038 A1 known lubricating grease compositions consisting of one or more esters of aromatic tri- or tetracarboxylic acids with an alcohol and / or one or more esters of trimethylolpropane, pentaerytritol or dipentaerytritol with aliphatic carboxylic acids, a urea-based thickener and anti-wear agents. The use of polymers, in particular partially or fully hydrogenated polyisobutylenes, is not described.

The DE 10 2006 043 747 A1 discloses the use of trimelite ester base materials in conjunction with polyol ester compounds and a complex ester base material and an additive package for providing a high-temperature oil. On the basis of this composition, it is to be expected that the formulations based purely on esters tend to lye.

The EP 2 714 872 B1 discloses a high-temperature oil based on aromatic esters, such as trimellitic acid esters, pyromellitic acid esters, trimesic acid or mixtures thereof and hydrogenated polyisobutylene, which is provided without a solubilizer, so as to avoid evaporation losses in the Avoid application.

The US 2006/0073989 A1 relates to a grease composition used at high temperatures and speeds in electrical parts of automobiles or auxiliary machines of engines and consists of an aromatic ester oil such as trimellitic ester oil or pyromellitic ester oil and a diurea thickener.

1. a) 91,9 bis 25 Gew.-% mindestens eines Öls, ausgewählt aus der Gruppe bestehend aus Trimellitsäureestern, oder einem Gemisch aus verschiedenen Trimellitsäureestern, bei dem die Alkoholgruppe des Esters eine lineare oder verzweigte Alkylgruppe mit 8 bis 16 Kohlenstoffatomen ist,
2. b) 6 bis 45 Gew.% eines Polymers, nämlich eines hydrierten oder vollhydrierten Polyisobutylen oder einer Mischung aus hydrierten oder vollhydrierten Polyisobutylen;
3. c) 0,1 bis 10 Gew.-% Additive einzeln oder in Kombination, ausgewählt aus der Gruppe bestehend aus Korrosionsschutzadditiven, Antioxidantien, Verschleißschutzadditiven, UV-Stabilisatoren, anorganischen oder organischen Feststoffschmierstoffen und
4. d) 2 bis 20 Gew.-% Verdickungsmittel.

According to the invention, this object is achieved by a high-temperature grease comprising the following components:

1. a) 91.9 to 25% by weight of at least one oil selected from the group consisting of trimellitic acid esters, or a mixture of different trimellitic acid esters, in which the alcohol group of the ester is a linear or branched alkyl group with 8 to 16 carbon atoms,
2. b) 6 to 45% by weight of a polymer, namely a hydrogenated or fully hydrogenated polyisobutylene or a mixture of hydrogenated or fully hydrogenated polyisobutylene;
3. c) 0.1 to 10% by weight of additives, individually or in combination, selected from the group consisting of corrosion protection additives, antioxidants, wear protection additives, UV stabilizers, inorganic or organic solid lubricants and
4. d) 2 to 20% by weight of thickener.

Surprisingly, it was found that the high-temperature grease is characterized by excellent performance. The high-temperature grease according to the invention shows high thermal stability combined with a long service life and good lubricating properties.

The high-temperature grease according to the invention comprises, as an ester compound, a trimellitic acid ester or a mixture of different trimellitic acid esters, the alcohol group of the ester being a linear or branched alkyl group having 8 to 16 carbon atoms. Depending on the choice of aromatic ester, the properties of the lubricant, for example the viscosity, the viscosity-temperature behavior, the oxidation resistance and residue behavior can be adjusted.

The high temperature grease according to the invention can contain a second oil which comprises an alkyl aromatic. An aromatic is preferably used. According to the invention, an aromatic is understood to mean a monocyclic, bicyclic or tricyclic ring system with four to fifteen carbon atoms, the monocyclic ring system being aromatic or at least one of the rings in a bicyclic or tricyclic ring system being aromatic. A bicyclic ring system, which preferably has 10 carbon atoms, is preferably used.

The aromatic is preferably substituted by one or more aliphatic substituents. The aromatic is particularly preferably substituted with one to four aliphatic substituents and in particular with two or three aliphatic substituents.

According to the invention, an alkyl group is a saturated aliphatic hydrocarbon group having 1 to 30, preferably 3 to 20, more preferably 4 to 17 and in particular 6 to 15 carbon atoms. An alkyl group can be linear or branched and is optionally substituted with one or more of the above-mentioned substituents.

The high-temperature grease according to the invention further comprises a polyisobutylene. A suitable choice of polyisobutylene, in particular with regard to the degree of hydrogenation and molecular weight, can influence the properties of the fat according to the invention, for example its kinematic viscosity, in the desired manner. The polyisobutylene can be used in hydrogenated or fully hydrogenated form, and a mixture of hydrogenated and fully hydrogenated polyisobutylene can also be used. Fully hydrogenated polyisobutylenes are preferably used. The polyisobutylene is present in the composition in an amount of 6 to 45% by weight, preferably 10 to 45% by weight, in particular 15 to 45% by weight, are used.

According to a further preferred embodiment, the polyisobutylene has a number average molecular weight of 115 to 10,000 g / mol, preferably 160 to 5000 g / mol.

The high-temperature grease according to the invention also comprises from 0.1 to 10% by weight, additives, which are used individually or in combination and are selected from the group consisting of corrosion protection additives, antioxidants, wear protection additives, UV stabilizers, inorganic or organic solid lubricants.

The high-temperature grease according to the invention also comprises a thickening agent. The thickener in the high-temperature grease of the lubricant composition according to the invention is either a reaction product of a diisocyanate, preferably 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene, 4,4'-diisocyanatodiphenylmethane, 2,4'-diisocyanatophenylmethane, 4,4'-diisocyanatodi- phenyl, 4,4'-diisocyanato-3-3'-dimethylphenyl, 4,4'-diisocyanato-3,3'-dimethylphenylmethane, which can be used individually or in combination, with an amine of the general formula R ' ₂ -NR , or a diamine of the general formula R ' ₂ -NR-NR' ₂ , where R is an aryl, alkyl or alkylene radical having 2 to 22 carbon atoms and R ', identically or differently, is a hydrogen, an alkyl, alkylene or aryl radical is, or with mixtures of amines and diamines
or
is selected from Al complex soaps, metal single soaps of the elements of the first and second main group of the periodic table, metal complex soaps of the elements of the first and second main group of the periodic table, bentonites, sulfonates, silicates, Aerosil, polyimides or PTFE or a mixture of the above Thickener.

As additives for high-temperature greases, the following additives have particularly good physical and chemical properties:
The addition of antioxidants can reduce or even prevent the oxidation of the oil or fat according to the invention, especially when it is used. In the event of oxidation, undesirable free radicals can arise and, as a result, more decomposition reactions of the high-temperature lubricant occur. The high temperature fat is stabilized by adding antioxidants.

Antioxidants particularly suitable according to the invention are the following compounds:
Styrenated diphenylamines, diaromatic amines, phenolic resins, thiophenolic resins, phosphites, butylated hydroxytoluene, butylated hydroxyanisole, phenyl-alphanaphthylamine, phenyl-beta-naphthylamine, octylated / butylated diphenylamine, dialpha-tocopherol, phenyl-phenyl-phenol, sulfur-propane, phenyl-tert-butyl-phenyl compounds , Phenolic compounds and mixtures of these components.

The high-temperature grease can also contain corrosion protection additives, metal deactivators or ion complexing agents. These include triazoles, imidazolines, N-methylglycine (sarcosine), benzotriazole derivatives, N, N-bis (2-ethylhexyl) -ar-methyl-1H-benzotriazole-1-methanamine; n-Methyl-N (1-oxo-9-octadecenyl) glycine, mixture of phosphoric acid and mono- and diisooctyl esters reacted with (C _11-14 ) -alkylamines, mixture of phosphoric acid and mono- and diisooctyl esters reacted with tert-alkylamine and primary (C _12-14 ) amines, dodecanoic acid, triphenyl phosphorothionate and amine phosphates. Commercially available additives are the following: IRGAMET® 39, IRGACOR® DSS G, amine O; SARKOSYL® O (Ciba), COBRATEC® 122, CUVAN® 303, VANLUBE® 9123, CI-426, CI-426EP, CI-429 and CI-498.

Further anti-wear additives are amines, amine phosphates, phosphates, thiophosphates, phosphorothionates and mixtures of these components. The commercially available anti-wear additives include IRGALUBE® TPPT, IRGALUBE® 232, IRGALUBE® 349, IRGALUBE® 211 and ADDITIN® RC3760 Liq 3960, FIRC-SHUN® FG 1505 and FG 1506, NA-LUBE® KR-015FG, LUBEBOND .®, FLUORBOND ® FG, SYNALOX® 40-D, ACHESON® FGA 1820 and ACHESON® FGA 1810.

Furthermore, the grease can contain solid lubricants such as PTFE, BN, pyrophosphate, Zn oxide, Mg oxide, pyrophosphates, thiosulfates, Mg carbonate, Ca carbonate, Ca stearate, Zn sulfide, Mo sulfide, W sulfide, Sn -Sulfide, graphite, graphene, _{nanotubes, SiO 2} modifications or a mixture thereof.

Practical tests have shown that the high-temperature grease according to the invention shows no or negligible decomposition phenomena up to a temperature of 250 ° C. This means that less than 10% of the lubricant decomposes.

The high-temperature grease according to the invention can contain, as a further base oil, an oil, preferably selected from the group consisting of mineral oil, aliphatic carboxylic acid and dicarboxylic acid esters, fatty acid triglycerides, pyromellitic acid esters, diphenyl ethers, phloroglucinic esters and / or poly-alpha-olefins, alpha-olefin copolymers.

Practical tests have shown that the high-temperature grease according to the invention, due to its physical and chemical properties, is excellent for use in chains, roller and plain bearings, in vehicle technology, conveyor technology, mechanical engineering, office technology and in industrial systems and machines, but also in the Areas of household machines and consumer electronics. Due to its good temperature resistance, it can also be used at high operating temperatures of up to 260 ° C, preferably at temperatures of 150 to 250 ° C.

The invention also relates to a method for producing the above-described high-temperature grease, in which the base oils and the additives are mixed with one another.

The invention will now be explained in more detail with reference to the following examples.

Reference examples 1 to 2 Production of a high temperature oil

Estolides or aliphatically substituted naphthalenes are placed in a stirred tank. At 100 ° C., the polyisobutylene and, if necessary, a further oil are added with stirring. Then the mixture is stirred for 1 hour to obtain a homogeneous mixture. The anti-wear agents and the antioxidant are added to the kettle at 60 ° C. while stirring. After approx. 1 hour, the finished oil can be filled into the containers provided.

Composition of high temperature oils:

Table 1 example 1 Comparative example 1 Trimellitate 0.0 63.0 Estolide 1 44.0 0.0 Estolide 2 19.0 0.0 hydrogenated PIB 30.4 30.4 amine antioxidant 2.0 2.0 phenolic antioxidant 1.0 1.0 Wear protection EP / WA 3.5 3.5 Corrosion protection 0.1 0.1 Solvability of the very good (4) very good (4) Residues Table 2 Example 2 Comparative example 2 Trimellitate 1 0 76.0 alkylated naphthalene 76.0 0.0 hydrogenated PIB 20.0 20.0 amine antioxidant 4.0 4.0 Solvability of the very good (4) very good (4) Residues

The basic data of the oil examples can be found in Table 3. <u> Table 3 </u> Recipe example 1 Comparative example 1 Example 2 Comparative example 2 Eisenmann test [250 ° C, 72h] Solvability 4th 4th 4th 4th Basic data Flash point (° C) > 250 > 250 > 250 > 250 kin. V40 280.0 270.0 300.0 140.5 kin. V100 29.00 25.0 25.00 16.13 VI 137 120.0 105 121

Furthermore, the friction behavior of the oils in the SRV was measured based on DIN 51834-2 and the evaporation loss in the dynamic TGA. The results are shown in Tables 4 and 5 and are graphed in FIG Figures 1 and 2 reproduced. <u> Table 4 </u> example 1 Comparative example 1 Example 2 Comparative example 2 SRV TST (250 N) 50 - 120 ° C 0.116 0.112 0.156 0.091 120-140 ° C 0.111 0.127 0.155 0.091 140-160 ° C 0.105 0.141 0.158 0.128 160-180 ° C 0.1 0.145 0.163 0.139 180-200 ° C 0.095 0.143 0.171 0.165 200-210 ° C 0.08 0.137 0.177 0.194 210-220 ° C 0.086 0.132 0.175 0.206 220-230 ° C 0.085 0.129 0.179 0.208 230-240 ° C 0.087 0.126 0.185 0.208 240-250 ° C 0.091 0.121 0.189 0.206 250 ° C isothermal 0.093 0.118 0.186 0,201 example 1 Comparative example 1 Example 2 Comparative example 2 TGA dynamic 120 ° C 0.1 0.1 0.1 0.1 140 ° C 0.3 0.2 0.3 0.2 160 ° C 0.6 0.5 0.4 0.4 180 ° C 1 0.9 0.9 0.7 200 ° C 1.7 1.4 1.8 1.2 220 ° C 2.8 2.3 3.6 2.2 240 ° C 4.6 3.7 6.6 3.7 260 ° C 7.7 5.9 11.7 6.3

Examples 3 and 6 and Reference Examples 4, 5, 7 and 8 Production of a high temperature grease according to the invention

The base oil is placed in a stirred tank. At 100 ° C., the polyisobutylene and, if necessary, a further oil and the thickener are added with stirring. The thickener results from an in situ reaction of the reactants used in the base oil. The mixture is then heated to 150 ° C. to 210 ° C., stirred for several hours and cooled again. In the cooling process at approx. 60 ° C, the necessary wear protection agents, antioxidants and corrosion protection agents are added. A homogeneous mixture of the fat is obtained by the final homogenization step using a roller, colloid mill or the Gaulin.

The compositions of the high-temperature greases are shown in Table 6, Examples 3 and 6 relating to a composition according to the invention. <u> Table 6 </u> Type Li complex Li complex Li complex Di-urea Di-urea Di-urea Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Trimellitic acid ester [wt. %] 60 0 0 65.2 0 0 Estolide [wt.%] 0 0 56 0 0 65.2 alkylated naphthalene [wt.%] 0 64 0 0 65.2 0 fully hydrogenated polyisobutylene [% by weight] 26th 25th 25th 25th 25th 25th Add itive package [wt.%] 4th 1 4th 1 1 1 Thickener concentration [wt.%] 10 10 15.0 8.8 8.8 8.8

• Beispiel 3: LiOH, 12-Hydroxystearinsäure, Azelainsäure,
• Beispiel 4: LiOH, 12-Hydroxystearinsäure, Azelainsäure,
• Beispiel 5: LiOH, 12-Hydroxystearinsäure, Azelainsäure,
• Beispiel 6: Di-Harnstoff; Methylen-Di-phenyl-diisocyanat (MDI), Octylamin, Oleylamin
• Beispiel 7: Di-Harnstoff; MDI, Octylamin, Oleylamin
• Beispiel 8: Di-Harnstoff; MDI, Octylamin, Oleylamin

The thickeners used in Examples 3 to 8 are:

• Example 3: LiOH, 12-hydroxystearic acid, azelaic acid,
• Example 4: LiOH, 12-hydroxystearic acid, azelaic acid,
• Example 5: LiOH, 12-hydroxystearic acid, azelaic acid,
• Example 6: Di-urea; Methylene-diphenyl-diisocyanate (MDI), octylamine, oleylamine
• Example 7: di-urea; MDI, octylamine, oleylamine
• Example 8: di-urea; MDI, octylamine, oleylamine

The general characteristics of the fat samples 3 to 8 are shown in Table 7. <u> Table 7 </u> Characteristics Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Walpenentration according to 60 DT [DIN ISO 2137] 284 283 278 232 232 300 Walpenentration according to 100000 DT [DIN ISO 2137] 324 319 319 254 254 338 Drop point [C °] [DIN ISO 2176] > 300 > 300 > 300 > 300 280 292 Flow pressure -20 ° C; [mbar] [DIN 51805] > 2000 275 284 575 525 <1400 Flow pressure -30 ° C; [mbar] [DIN 51805] > 2000 425 675 <1400 <1400 <1400 Oil cut-off 40 ° C / 168h; [% By weight] [DIN 51817] 3.80 3 1.70 1.2 0.10 5.60 Oil cut-off 150 ° C / 30h; [% By weight] [FTMS 761 C] 7.4 7.5 2.50 0.20 0.30 5.00 Evaporation loss 150 ° C / 24 ° C [DIN 58397 part 1] 2 5.3 2.50 1.6 3.5 2.1 Static water resistance [DIN 51807] 1 2 1.00 0 1 1

The evaporation losses of the various fat samples at 150 ° C after 30 hours are between 2% and 5%, which underlines the very good thermal stability of these fat concepts.
Oil separation has a decisive influence on the lubricating effect of a grease. It must be ensured that, on the one hand, the oil separation is not too high and the oil runs out of the bearing and is therefore no longer available to the tribo-system and, on the other hand, no oil separation can be observed and the lubricating effect of the grease is lost. The oil separation should ideally be between 0.5 and 8% by weight so that an optimal lubricating film can form in the bearing.

The greases in the examples were subjected to an FE 9 roller bearing test according to DIN 51 821, in which the service life of the greases examined is determined and the upper service temperature of lubricating greases in roller bearings at medium speeds and medium axial loads is determined.
The fats tested and the results of the L10 and L50 values are shown in Table 8. <u> Table 8 </u> Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 FE 9 [180 ° C, 6000 rpm, 1500N] L 50 (h) 249 > 100 207 146 > 100 > 100 L 10 (h) 169 > 50 138 72 > 50 > 50

Table 8 shows that the running times due to the use of PIB in conjunction with various base oils have long running times and are therefore suitable for high application temperatures in continuous operation.

In addition, the noise behavior after the SKF Be Quiet ⁺ fats according to Examples 3 to 8 was measured. The results are given in Table 9. <u> Table 9 </u> Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Noise test [BeQuiet + SKF] GN4 GN3 GN3 GN2 GN3 GN4

The use of fully hydrogenated polyisobutylene has a very positive effect on the noise behavior of the various fat formulations. With the exception of Example 6, good to very good noise properties can be achieved.

The properties of the fat according to Example 3, in which fully hydrogenated PIB was used, was now compared with a fat (comparative example 3) that contained a PIB in which double bonds were still present, that is to say a not fully hydrogenated PIB.
The other composition of the fat according to comparative example 3 corresponded to that of example 3. <u> Table 10 </u> Example 3 Comparative example 3 FE 9 [180 ° C, 6000 rpm, 1500N] L 50 (h) 249 126 L 10 (h) 169 72 Noise test [BeQuiet + SKF] GN4 GN1 Loss of evaporation [DIN ISO 58397] 170 ° C / 24h 4.3 5.1 Evaporation loss [DIN ISO 58397] 180 ° C / 24h 6.9 7.4 Walpenentration according to 60 DT [DIN ISO 2137] 284 301 Walpenentration according to 100000 DT [DIN ISO 2137] 324 356 Corrosion effect of lubricants on copper [DIN ISO 51811] 150 ° C / 24h 1a n / A Oil cut-off 150 ° C / 30h; [% By weight] [ASTM D 6184] 7.4 8.4 Oil cut-off 150 ° C / 30h; [% By weight] [ASTM D 6184 17.9 14.7 Oil cut-off 168 ° C / 40h; [% By weight] [DIN 51817] 3.8 6.5 Testing of fat greases for corrosion-preventing properties [DIN 51801 / ISO 11007] 0 n / A Drop point [C °] [DIN ISO 2176] > 300 295.0 Evaporation loss 150 ° C / 24 ° C [DIN 58397 part 1] 2 2.4 Static water resistance [DIN 51807] 90 ° C 0 n / A

The comparison of the fats with fully hydrogenated PIB and not fully hydrogenated PIB in Table 10 shows that the fat of Example 3 shows a doubled running time in the FE9 test, has lower evaporation losses and a significantly better noise behavior.

Claims (4)

1. A high-temperature grease, comprising

   a) 91.9 to 25 wt.-% of at least one oil, selected from trimellitic acid esters or a mixture of different trimellitic acid esters, in which the alcohol group of the ester is a linear or branched alkyl group with 8 to 16 carbon atoms;

   b) 6 to 45 wt.-% of a polymer, selected from the group consisting of a hydrogenated or fully hydrogenated polyisobutylene or a mixture of hydrogenated or fully hydrogenated polyisobutylene;

   c) 0.1 to 10 wt.-% of additives, alone or in combination, selected from the group consisting of corrosion-protection additives, antioxidants, wear-protection additives, UV stabilisers, inorganic or organic solid lubricants and

   d) 2 to 20 wt.-% of thickener.
2. The high-temperature grease according to claim 1, in which the oil component comprises, as further oil, a compound selected from the group consisting of mineral oil, aliphatic carboxylic acid and dicarboxylic acid esters, fatty acid triglycerides, pyromellitic acid esters, diphenyl ether, phloroglucinol ester and/or polyalphaolefins, alpha olefin copolymers.
3. The high-temperature grease according to claim 1, in which the thickener is selected from the group consisting of urea, aluminium complex soaps, metal simple soaps of the elements of the first and second main group of the periodic table, metal complex soaps of the elements of the first and second main group of the periodic table, bentonites, sulfonates, silicates, aerosil, polyimides, PTFE or a mixture of the aforementioned thickeners.
4. A use of the high-temperature grease according to one of the preceding claims for lubricating rolling contact bearings and friction bearings in automotive engineering, materials handling technology, manufacturing systems engineering, office technology and in industrial installations and machines, but also in the fields of domestic machines, consumer electronics and for lubricating chains, chain rollers and belts of continuous presses.

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