WO2017029287A1

WO2017029287A1 - Lubricating grease composition

Info

Publication number: WO2017029287A1
Application number: PCT/EP2016/069423
Authority: WO
Inventors: Rachel Kling; Alexander GRECHIN; Bernard FISIC; Karl-Heinz Hensel
Original assignee: Setral Chemie Gmbh
Priority date: 2015-08-20
Filing date: 2016-08-16
Publication date: 2017-02-23
Also published as: EP3337879A1; EP3337879B1; CN108026465A; ES2902836T3; HK1257564A1; US20180245010A1

Abstract

The invention relates to lubricating grease compositions comprising (a) at least one highly viscous, fluorinated oil having a viscosity of between 500 - 1500mm²/s, (b) boron nitride and (c) a binder which is selected from bentonite, alkali metal phosphates, aluminum phosphates, alkali metal silicates, alkaline earth metal silicates, aluminum silicates, alkaline earth metal carbonates, calcium borate, silicon dioxide, titanium dioxide, aluminum oxide and mixtures thereof. Said lubricating grease compositions can be used, in particular, in a high-temperature range, for example for greasing oven drawer rails.

Description

Grease compositions

The present invention relates to lubricating grease compositions which are particularly suitable as high-temperature lubricating greases and for lubrication in kiln systems,

Dryers, dishwashers, electric motors or fans find application.

Greases generally contain a thickener dissolved or dispersed in a base oil, often with dispersants for better and more stable distribution of the thickener. The thickener is used to adjust the desired consistency, with a variety of inorganic and organic

Connections is used.

The base oils are mineral oils and synthetic oils. Frequently, perfluorinated polyalkyl ethers (PFPE), i. fluorinated synthetic oils with good lubricating properties that are chemically non-reactive, high temperature stable and therefore non-toxic (see, e.g.

&Quot; Synthetics, Mineral Oils & Bio-Based Lubricants ", Leslie R. Rudnick Ed., Taylor & Francis, CRC Press, 2006), WO 97/47710 describes lubricating grease compositions containing as a base oil a mixture of a hydrocarbon oil and a perfluorinated one

Polyalkyletheröl (PFPE) and a thiourea-based thickener. The composition may also include polytetrafluoroethylene (PTFE) and conventional additives.

EP 657 524 describes lubricating grease compositions comprising a hydrogenated base mineral oil and / or a synthetic oil, a perfluorinated polyalkyl ether oil and a

Thickener PTFE included.

DE 10 2004 021 812 A1 describes a lubricating grease containing a base oil

Thickening agent, in particular a polyurea, and a distributed in the grease inorganic material such as silica.

WO 2008/154997 A1 describes a grease containing a base oil, an ionic liquid, a thickener and an additive. The ionic liquid should cause an increase in the life and lubricity of the lubricant and serve to adjust the viscosity and the electrical conductivity.

In the higher temperature range (200 ° C to over 600 ° C) encounter many of the known

Lubricants, such as polyfluorinated compounds, to the limits of Material resilience and are therefore no longer applicable in spite of excellent sliding and lubricating properties in the higher temperature range.

WO 2013/037456 therefore describes high-temperature fats which contain a fluorine-free base oil, a thickener which may be PTFE, additives and optionally a further fluorine-free oil component.

EP 1589291 A1 discloses a furnace exhaust guide having rolling elements arranged in a rolling element cage. In this case, the Wälzkörperkäfig and

Rolling on a lubricating layer containing a solid lubricant, e.g. Graphite,

Molybdenum sulfide, tungsten disulfide or boron nitride, and which is applied and baked in the form of a paint

WO 2010/046456 A1 describes a pullout guide for an oven, in which the tracks of the pullout guide are lubricated with boron nitride and / or a lubricant containing polysiloxane.

EP 648 832 A1 describes lubricating grease compositions which are fluorinated

Polymer oil, boron nitride and optionally solid fluorinated polymers. The

Grease compositions are said to have good lubricating properties even under harsh operating conditions.

US 2008/0167208 describes grease compositions containing a

Perfluoropolyether oil having a kinematic viscosity of 50-1500 mm ² / s at 40 ° C, optionally contain a thickener and other conventional additives. The

Grease compositions are also believed to be useful in contact with graphite or molybdenum disulfide at higher temperatures.

PTFE-containing greases form toxic fumes at higher temperatures and are also relatively quickly washed out during cleaning operations by water. PTFE-free greases in turn have the disadvantage that they are washed out even faster by water than PTFE-containing greases.

The object of the present invention is therefore to provide lubricating grease compositions with improved water washability. In addition, the lubricating grease compositions are said to have improved temperature stability and to provide a longer lubricating life at high temperatures. This object is achieved by a grease composition comprising at least one high-viscosity, fluorinated oil, hexagonal boron nitride and a binder. The present invention therefore relates to a grease composition comprising

(A) at least one fluorinated oil having a viscosity of 500 to 1500 mm ² / s, preferably 500 to 1 100 mm ² / s;

(b) boron nitride and

(c) a binder.

The kinematic viscosity is measured with SVM 300 Viscometer, Anton Paar at a temperature of 40 ° C.

In one embodiment, component (a) comprises fluorinated, in particular perfluorinated, polyalkyl ether oils or fluorinated silicone oils, in particular perfluorinated silicone oils, and

Mixtures thereof.

Suitable perfluorinated polyalkyl ether oils are described, for example, in WO 97/47710 or EP 657 524, to which reference is made in its entirety.

According to one embodiment, the perfluorinated polyalkyl ether oils correspond to the formula:

A ¹ - [OCF ₂ ] _a - [OC ₂ F ₄ ] _b - [OC ₃ F ₆ ] _c - [OC ₄ F ₈ ] _d - [OCF ₂ CF (CF ₃ )] _e - [OCF (CF ₃ ) CF ₂ ] _f - A ² wherein

A ^{1 is} -CF ₃ , -C ₂ F ₅ , or -C ₃ F ₇ ;

A ^{2 is} -OCF ₃ , -OC ₂ F ₅ , or -OC ₃ F ₇ ; a, b, c, d, e and f are statistically distributed and are 0 or an integer from 1 to 200, wherein not all of them can simultaneously stand for 0.

According to a further embodiment, e / a and f / a are in the range of 20 to 50 and b / a in the range of 0.5 to 2. According to another embodiment, c and d are 0. Particularly preferred are the perfluorinated polyalkyl ethers of the following units:

- [OCF ₂ CF (CF ₃ )] _e or - [OCF ₂ ] _a - [OC ₂ F ₄ ] _b or

- [OCF ₂ ] _a - [OCF ₂ CF (CF ₃ )] _e

where e / a is in the range of 20 to 50 and b / a is in the range of 0.5 to 2. According to another embodiment, the perfluorinated polyalkyletherols correspond to the formula:

CF ₃ - [OCF (CF ₃ ) CF ₂ ] _f - [OCF ₂ ] _a - [OCF ₂ CF (CF ₃ )] _e - OCF ₃ wherein a, e and f are randomly distributed and represent 0 or an integer of 1 to 200, not all of which can simultaneously stand for 0 and e / a and f / a are in the range of 20 to 50.

According to another embodiment, the perfluorinated polyalkyletherols correspond to the formula:

Τ-0- [Α-Β] _ζ - [Α-Β '] _ζ -Α-Τ' (I) wherein:

A = - (X) _a -O-A '- (X') _b - where A 'is a perfluoropolyether chain containing one or more of (CF ₂ O),

(CF ₂ CF ₂ O), (CF ₂ CF ₂ CF ₂ O) and (CF ₂ CF ₂ CF ₂ CF ₂ O) selected repeating units and optionally (CF (CF ₃ ) O) -, (CF (CF ₃ ) CF ₂ 0), (CF ₂ CF (CF ₃ ) O) units;

X and X 'are the same or different and are -CF ₂ -, -CF ₂ CF ₂ - or

optionally -CF (CF ₃ ) - stand;

a and b are the same or different and stand for integers having a value of 0 or 1, with the proviso that in the case of the block A bound to the end group TO, the subscript a stands for 1 and in which the end group T ' bound block A, the index b is 0;

B is a block of units derived from one or more olefins of the formula (Ia) of which at least one is free-radically homopolymerizable

- [(CRiR ₂ -CR ₃ R ₄ ) _j (CR ₅ R ₆ -CR ₇ R ₈ ) _j ] - (la) wherein

j is an integer from 1 to 5, j 'is an integer from 0 to 4, with the proviso that (j + j') is greater than 2 and less than 5;

Ri, R2, RSS, R _4, R _E, R 6, R 7 and R ₈ are identical or different and are selected from halogen; H; CrC ₆ - (per) haloalkyl, wherein the halogen is F and / or Cl; C 1 -C ₆ -alkyl optionally containing heteroatoms; and CrC ₆ -oxy (per) fluoroalkyl are selected;

z is an integer greater than or equal to 2;

z 'is 0 or an integer;

wherein z and z 'are such that the number average molecular weight of the polymer of formula (I) is in the range of 500-500,000;

B 'is a block which is derived from one or more olefins of the formula (Ia), but where at least one of the substituents R 1 to R _{8 is} different than in block B, where (j + j') is greater than or equal to 2 and less than 5;

the end groups T and T 'are the same or different and for

Perfluoroalkyl groups having 1 to 3 carbon atoms, wherein a fluorine atom may be replaced by a chlorine or hydrogen atom; or non-fluorinated C 1 -C ₆ -alkyl groups.

These polyether oils are described in EP 2 089 443, to the disclosure of which, in particular to the embodiments disclosed in the claims, is fully incorporated by reference.

In one embodiment, component (a) may additionally comprise a non-fluorinated oil, in particular a mineral oil. The non-fluorinated oil is generally contained in an amount of 0.1 to 40% by weight, more preferably 0.5 to 30% by weight, based on the amount of the fluorinated oil.

The grease composition further comprises boron nitride, especially hexagonal boron nitride. In one embodiment, the grease composition comprises hexagonal α-boron nitride. According to another embodiment, the boron nitride has a BET surface area in the range of 10 to 20 m ² / g, determined according to ISO 9277: 2010. According to a further embodiment, the boron nitride has an average particle size D50 of 1 to 10 μm, in particular 2 to 6 μm, determined by means of laser diffractometry (Malvern Mastersizer 3000). A suitable boron nitride, for example, under the trade name BORONID ^® from ESK Ceramics GmbH & Co. KG, Germany, available. The grease composition further comprises a binder. The binder generally has an average particle size D50 in the range of 1 to 10 μm, preferably 2 to 8 μm, determined by means of laser diffractometry. In one embodiment, the binder is selected from bentonite,

Alkali metal phosphates, aluminum phosphates, alkali metal silicates, alkaline earth metal silicates, aluminum silicates, alkaline earth metal carbonates, calcium borate, silica, titania, alumina, and mixtures thereof. Preference is given to bentonite, alkali metal phosphates, aluminum phosphates and mixtures thereof. Particularly preferred is the binder organically modified bentonite or a mixture of organically modified bentonite with at least one further binder selected from alkali metal phosphates, aluminum phosphates, alkali metal silicates, alkaline earth metal silicates, aluminum silicates, alkaline earth metal carbonates, silica, titania, alumina and mixtures thereof. The further binder is generally contained in an amount of 0.1 to 50 wt .-%, in particular 0.5 to 40 wt .-%, based on the amount of organically modified bentonite.

As the silica, organically modified fumed silica is preferable, and as the titania, organic-modified fumed titania is preferable. Modified fumed silica and modified fumed titanium dioxide are products that have been surface-treated with an organosilane, especially with an alkylsilane. Corresponding products such as Aerosil R 912, Aerosil 812, Aerosil 805, Aerosil R 202, Aeroxide ^® Ti0 ₂ T 805, Aeroxide ^® Ti0 ₂ NKT 90, VP NKT 65 are commercially available, for example from Evonik Industries AG, Germany or Wacker Chemie AG, Germany.

Bentonite is a mixture of different clay minerals with the most important

Component montmorillonite (60% to 80%). Further accompanying minerals are quartz, mica, feldspar, pyrite or calcite. The term "bentonite" includes all of course

occurring versions as well as modified bentonites. Bentonite is commercially available in the form of various commercial products. In the context of the present invention, preference is given to using organically modified, in particular hydrophobically modified, bentonite, for example the commercial product BARAGEL® from Elementis Specialties Inc., USA. Organic hydrophobically modified bentonite can, for example, by the reaction of natural or purified bentonite with quaternary ammonium compounds in the sense of a cation exchange reaction in which, for example, alkali cations against quaternary Ammonium compounds are exchanged done. Quaternary ammonium compounds suitable for this reaction are, for example, those of the general formula R ¹ R ² R ³ R ⁴ N ⁺ X ^" , where X is one equivalent of an anion, for example sulfate, hydrogensulfate, alkylsulfate, arylsulfate, alkylsulfonate, arylsulfonate, halide, phosphate , carbonate, alkyl phosphate, alkyl carbonate, nitrate, alkoxide, hydroxide, tetrafluoroborate or perchlorate, in particular halide, and R ^1, R ^2, R ³ or R ⁴ may be the same or different and may stand for -C ₂ o alkyl. for example, R ¹ and R ^2, identical or different, represent -C ₄ alkyl and R ₃ and R _4, identical or different, are ₂ -C ₂ o-alkyl is Ci. in particular, quaternary ammonium salts can be used, where X is halide, in particular chloride, R ¹ and R ² are methyl and R ₃ and R _4, identical or different, are C ₆ -C ₈ -alkyl BARAGEL © The commercial product is bentonite modified with Me ₂ N (Ci. ₆ - Ci ₈ alkyl) ₂ CI.

When bentonite is used as the binder, in a preferred embodiment the lubricating grease composition additionally comprises water in an amount of 0.01 to 1% by weight, in particular 0.05 to 0.2% by weight, based on the total mass of the composition. Water serves as an activating agent for bentonite, in particular for activating the dispersing and thickening properties of the bentonite. According to a further embodiment, the lubricating grease composition according to the invention may contain at least one additive, in particular an additive which is customary in the field of lubricating grease compositions. Preferably, the additive is selected from antioxidants, for example, functionalized perfluoropolyalkyl ethers as described in EP 1 354 932 A1 and US 5,550,277; Wear protection additives, for example functionalized perfluoropolyalkyl ethers, as described in WO 2016/020232;

Corrosion inhibitors, for example sodium sebacate, functionalized perfluoropolyalkyl ethers as described in US 5,550,277; Dyes, for example azo dyes and solid lubricants, for example molybdenum disulfide, tungsten disulfide, tin sulfide. According to a further embodiment, the inventive

Grease composition

(a) 50-96% by weight of the fluorinated oil;

(b) 0.9-20 wt% boron nitride; and

(c) 3 to 25% by weight of the binder;

(d) 0-5% by weight, in particular 0.01-5% by weight, of at least one additive;

each based on the total weight of the composition. According to a further embodiment, the inventive

Grease composition (a) 50-96% by weight of at least one perfluorinated polyalkyl ether oil;

(b) 0.9-20 wt% boron nitride; and

(c) 3 to 25% by weight organically modified bentonite;

(d) 0-5% by weight, in particular 0.1-5% by weight, of at least one additive;

each based on the total weight of the composition.

In one embodiment, the lubricant composition is substantially free of PTFE.

In another embodiment, the grease composition is substantially free of an ionic liquid.

In another embodiment, the grease composition is substantially free of graphite. "Substantially free" means that the lubricating grease composition contains less than 0.5% by weight of PTFE, less than 0.5% by weight of ionic liquid or less than 0.5% by weight of graphite, in particular each 0% by weight. % of these components, based on the

Total mass of the composition containing. The preparation of the grease composition according to the invention takes place in

Generally by mixing the components under high shear, e.g. under

Using a rotor-stator mixer, optionally followed by a

Homogenization, e.g. using a roller mill. Surprisingly, it has been found that the invention

Grease compositions have a number of advantageous properties compared to known greases: very good compatibility of all components,

- better adhesion on metal surfaces

longer life at high operating temperature, less water washability; This results in the possibility of multiple mechanical cleaning of lubricated metal parts, for example, pull-out rails of ovens in dishwashers, without affecting the function of the metal parts

- No formation of toxic decomposition products when heated above 100 ° C

better high temperature properties

additional lubricating effect by the oil component compared to powdered products.

The lubricating grease compositions according to the invention are for lubrication in

Temperature range of - 30 ° C to 700 ° C, in particular + 20 to 300 ° C, suitable. They can therefore be used in many areas. So they are useful for the lubrication of sliding guides and impellers in kiln systems or rolling and plain bearings in

Dryers, electric motors or fans, for the lubrication of tools, in particular tools for plastic injection molding, machinery and equipment, in particular for the food and feed industry. Examples of applications include the lubrication of: Rolling and plain bearings, sliding guides, valves, joints, slides, column guides, ejectors and other sliding surfaces such as in

Circular conveyors, paint lines, calenders, kiln cars, fans, switches,

Film stretching plants, extraction plants, textile machines, wood press systems, pumps, dryers, motors, tire molds, construction machines, electrical and automotive engineering,

Elastomer and plastics technology as well as applications in the corrugated cardboard industry,

Paper industry and steel industry and machinery and equipment, e.g. in the food and feed industry.

Preferably, the grease composition according to the invention for the lubrication of sliding guides and wheels in kiln systems or rolling and sliding bearings in

Dryers, electric motors or fans used. Particularly preferred is the use of the grease compositions according to the invention for the lubrication of Ofenauszugsschienen.

The application of the grease composition is carried out by applying to the parts to be lubricated in a suitable amount for lubrication. Preferably, the grease composition of the invention is applied as a paste. These

Application form allows a very exact selection and coating of the

Application surfaces. The grease composition can be easily applied be without the grease composition, for example, at the ends of the tracks of Ofenauszugsschienen run out or drip.

Optional post-treatment after application of the lubricating grease composition by vibratory grinding allows better distribution and adhesion of the grease on, for example, a metallic substrate.

Preferably, the lubricant composition is thixotropic, i. upon mechanical action the viscosity decreases and the original viscosity returns after the end of the shear stress. This allows the pastes to be relatively easily spread on the surface of, for example, oven tray rails under pressure loading without dripping.

The following examples illustrate the invention without limiting it.

Example 1 :

Two perfluorinated polyether oils (68% by weight PFPE oil 1, 500 cSt at 40 ° C from DuPont, USA and 10% by weight PFPE oil 2, 1005 cSt at 40 ° C from DuPont, USA) were combined into one

Mixed kettle and heated with stirring for 15 min at 100 ° C. Thereafter, BARAGEL® (14.9 wt%, organic hydrophobically modified bentonite from Elementis Specialties Inc., USA) was added to the mixing kettle, the heater was turned off, and the resulting mixture was stirred for five minutes. Then, 0.1% by weight of water was added and the mixture was stirred for 30 minutes. After cooling to room temperature, boron nitride (5% by weight Boronid®, ESK Ceramics GmbH & Co. KG, Germany) and a corrosion inhibitor (2% by weight, Irgacor®, BASF SE, Germany) were added to the mixing vessel and the resulting Mixture was stirred for 30 min. The resulting

Grease was homogenized with a roller mill. The data in% by weight are each based on the total weight of the grease.

Test program and results

The grease composition prepared according to Example 1 was first subjected to a VKA test (four-ball apparatus, ASTM D1831 / DIN 51350-4). The VKA welding force became 4800 N and the VKA wear 0.9 mm at 150 kg / 1 min

Load determined. For the grease composition prepared according to Example 1, the thermal stability at 300 ° C was determined. As a measure of the thermal stability, the evaporation rate was used over time: hours: 0 24 72 140

Evaporation rate [%]: 0 14 26 41

In addition, for the lubricating grease composition prepared according to Example 1

- Steel corrosion (Emcor) in distilled water (ISO 1 1007): grade 1/1

- the base oil viscosity at 40 ° C (DIN 51562): 575 mm ² / s and

- the NLGI consistency class (DIN 51818): NLGI 1

certainly.

Auswaschbarkeitstests

For the grease composition prepared according to Example 1 and three

Comparative samples (Comparative Example 1, Comparative Example 2, Comparative Example 3) were carried out washability tests. For this, the various samples were on

Ofenauszugsschienen applied and exposed to the following cycle: The

Ofenauszugsschienen were exposed in an oven for 4 hours at a temperature of 250 ° C; Thereafter, the rails were removed from the oven and treated at 70 ° C for 2h with a commercial dishwashing detergent in a dishwasher; After the wash, the rails were removed from the dishwasher and dried at 105 ° C for 1 h. (3 cycles were performed for each sample, so the bars were in the oven for a total of 12 hours and in the dishwasher for 6 hours). Composition of the comparative examples (% by weight, based on the total weight of the composition):

Comparative Example 1

74.75% PFPE (perfluorinated polyether, 500 mm ² / s)

25% PTFE (polytetrafluoroethylene)

0.25% corrosion inhibitor

Comparative Example 2:

81% PFPE (500 mm ² / s)

10% PFPE (1005 mm ² / s)

5% PTFE

2% SiO 2 2% corrosion inhibitor

Comparative Example 3

10% PFPE (1005 mm ² / s)

83% PFPE (500 mm ² / s)

5% boron nitride

1% graphite

1% WS ₂ (tungsten sulfide)

The following results were obtained:

Example 1: weight loss after the third wash: <50%; Rail is easy to move.

Comparative Example 1: Weight loss after the third wash: 75%

Comparative Example 2: Weight loss after the third wash: 50%

Comparative Example 3: Weight loss after the third wash: 60%

The PTFE-containing Comparative Example 2 develops toxic, vaporous

Decomposition products and therefore, despite good washout results, not for one

Use in ovens suitable.

Endurance tests

For the grease composition prepared according to Example 1 and two

Comparative samples (Comparative Examples 4 and 5) were run endurance tests. For this purpose, the various samples were applied to furnace extension rails and the pull-out rails mounted on side rails. Then the grids were installed in an oven. A test load was placed in the middle of a baking tray in the oven. The entry and exit of the weighted baking sheet was carried out using a

Pneumatic cylinder performed. The rails were subjected to an endurance test with 24000 cycles. After every 6000 cycles, motive force and lowering of the rails were checked, and also after every 6000 cycles, the rails were subjected to a dishwasher washing cycle. After a total of 24,000 cycles was the

Disassembly and inspection of the rails. The test was carried out with the following parameters and according to the following schematic sequence: Test parameters: Cycles: 24000

Payload: 7,5kg

Temperature: 250 ° C

Speed .: 10 cycles / min

Level: middle level of the oven

Excerpt: limit by 20 mm in both directions

Test procedure: 1. Installation of the rails

2. Apply the test load in the middle of the baking tray

3. Endurance test 24000 cycles

4. Determining the motive force and lowering each after 6000 cycles

5. Rinsing machine each after 6000 cycles

6. Disassembly and inspection of the rails

7. Evaluation

Composition of the comparative examples (wt .-%, based on the total weight of

Composition):

Comparative Example 4

as Comparative Example 2, see above.

Comparative Example 5:

90.5% PFPE (500 mm ² / s)

6% boron nitride

3.25% Si0 ₂

0.25% corrosion inhibitor

The following results were obtained:

Example 1: The sample passed the test (5 washes, good

Running properties up to 18000 cycles, further up to 24000 cycles slightly worse running properties).

Comparative Example 4: The sample passed the test (5 washes, good

Running properties up to 18000 cycles, further up to 24000 worse running properties). However, the composition will develop toxic decomposition products at temperatures above 250 ° C.

Comparative Example 5: The sample failed the test (failed after 12,000 cycles, balls stuck for lack of greasing).

Claims

claims

1 . A grease composition comprising

(a) at least one fluorinated oil having a viscosity of 500 to 1500 mm ² / s at 40 ° C;

(b) boron nitride and

(c) at least one binder selected from bentonite,

Alkali metal phosphates, aluminum phosphates, alkali metal silicates,

Alkaline earth metal silicates, aluminum silicates, alkaline earth metal carbonates, calcium borate, silica, titania, alumina, and mixtures thereof.

2. The grease composition according to claim 1, comprising, in each case based on the total weight of the composition,

(a) 50-96% by weight of the fluorinated oil;

(b) 0.9-20 wt% boron nitride; and

(c) 3 to 25% by weight of the binder.

The grease composition according to claim 1 or 2, wherein the fluorinated oil having a viscosity of 500 to 1100 mm ² / s at 40 ° C.

A grease composition according to any one of the preceding claims, wherein the fluorinated oil is selected from perfluorinated polyalkyl ether oils, perfluorinated silicone oils and mixtures thereof, and in particular is selected from perfluorinated

Polyalkyletherölen and mixtures thereof.

5. The grease composition according to any one of the preceding claims, wherein the binder is selected from bentonite, fumed silica (Si0 ₂ ), talc

(Magnesium silicate hydrate), calcium carbonate, calcium borate, pyrogenic titanium dioxide,

Alumina and mixtures thereof.

6. A grease composition according to any one of the preceding claims, wherein the binder is organically modified bentonite or a mixture of organically modified bentonite with at least one further binder, which is selected from

Alkali metal phosphates, aluminum phosphates, alkali metal silicates, alkaline earth metal silicates, aluminum silicates, alkaline earth metal carbonates, silica, titania, alumina, and mixtures thereof.

A grease composition according to any one of the preceding claims wherein the boron nitride is hexagonal boron nitride, especially hexagonal α-boron nitride.

A grease composition according to any one of the preceding claims, which contains substantially no PTFE.

A grease composition according to any one of the preceding claims, which contains substantially no ionic liquid.

A grease composition according to any one of the preceding claims, which contains substantially no graphite.

1 1. A grease composition according to any one of the preceding claims additionally comprising at least one non-fluorinated oil.

A grease composition according to any one of the preceding claims additionally comprising 0.01 to 1% by weight of water based on the total weight of the composition.

13. A grease composition according to any one of the preceding claims, additionally comprising at least one additive.

The grease composition of claim 13, wherein the additive is selected from antioxidants, viscosity index improvers, pour point depressants, antiwear additives, anticorrosion agents, rust inhibitors, dyes, and solid lubricants.

15. A grease composition according to claim 14 comprising 0.05-5% by weight of at least one additive.

16. Use of a grease composition according to any one of claims 1 to 15 for lubrication in the temperature range of - 30 ° C to 700 ° C, in particular + 100 ° C to 310 ° C.

17. Use of a grease composition according to any one of claims 1 to 15 for the lubrication of sliding guides and wheels in kiln systems or Wälz- and Slide bearings in dryers, electric motors or fans, for the lubrication of

Tools, in particular tools for plastic injection molding, machines and installations, in particular for the food and animal feed industries.

18. Lubricating method, wherein applying a grease composition according to any one of claims 1 to 15 to the parts to be lubricated.

19. A lubricating method according to claim 18, wherein applying the lubricating grease composition in the temperature range of - 30 ° C to 700 ° C, in particular + 100 ° C to 310 ° C.

20. Lubrication method according to claim 18 or 19 for lubricating sliding guides and wheels in furnace systems or rolling and sliding bearings in dryers, electric motors or fans, for the lubrication of tools, in particular tools for the

Plastic injection molding, machines and installations, in particular for the food and animal feed industry.