WO1982003086A1

WO1982003086A1 - Pasty damping agent,method for preparing and using same

Info

Publication number: WO1982003086A1
Application number: PCT/EP1982/000043
Authority: WO
Inventors: Gmbh & Co Schiedel
Original assignee: Lochner Kaspar; Schuermann Helmut; Brand Erich
Priority date: 1981-03-03
Filing date: 1982-03-03
Publication date: 1982-09-16
Also published as: US4686057A; EP0073224B1; JPS57168997A; US4416790A; EP0059936A1; JPS58500408A; EP0073224A1

Abstract

The pasty damping agent is used to damp mechanical and/or acoustic oscillations. The agent contains as a minimum compound a solid finely divided substance or a mixture of solid finely divided substances, as a liquid phase, a silicone oil, a polyglycol, a mineral oil and/or a saturated or aromatic aliphatic carbon dioxide ester, an agent for increasing the activity of the limit layer or a surfactant, a magnesium and/or aluminum silicate and/or a silicon dioxide finely divided as a viscosity stabilizer and possibly a small quantity of an empty oxidiser. The damping agent is used in different hydraulic damping devices or for industrial vibration shock absorbers.

Description

Paste-like steaming medium, process for its production and its application

Description

The invention relates to a paste-like damping medium for damping mechanical and / or acoustic vibrations based on a liquid phase and at least one finely divided solid.

Damping media for damping mechanical vibrations are known. For example, hydraulic oils have been proposed as damping media. These oils have the disadvantage that the. Continuous exposure to heating of the steaming medium is not dissipated quickly enough and the oils are overheated and foam or decompose.

Silicone oils with hardener additives have also been used as damping media, which harden when subjected to sudden loads. However, due to the limited flowability, such dilated damping media can only be used for a few special damping processes. The hardening damping media also have the disadvantage that they have no sound-absorbing effect.

From US Pat. No. 3,812,937 a damping agent for hydraulically acting automobile impact dampers is known which consists of a low-viscosity petroleum oil which contains up to 20% by weight of an organophilic amine montmorillonite which is produced by reacting montmorillonite with an aliphatic amine salt , and contains acetonitrile, The known hydraulic oil is a thickened oil, but it is not suitable for damping high-frequency vibrations and for permanent loads, since it is unable to dissipate the heat occurring during the conversion of the shock and / or tensile loads quickly enough. At temperatures around 82 ° C, petroleum oil already decomposes, and the viscosity of the damping medium is significantly reduced even at temperatures below 82 ° C.

The invention was therefore based on the object of providing a damping medium which can be produced from cheap and easily accessible starting materials without the temperature stability of the viscosity of the damping medium and thus the flowability of the damping medium being impaired, and at the same time a higher storage stability of the paste is guaranteed.

The object is achieved by a damping medium of the type specified at the outset, which is characterized by the features of claims 1, 2 and 3.

Surprisingly, it was found that the graphite used as a solid in known damping media can be replaced by some selected other solids, even if they have a different structure and particle arrangement or packing. The addition of the solids listed in claims 1 and 2 has the advantage that the damping medium can be adjusted precisely to the desired damping process or the special damping element by the selection of the respective solid (solids) and that the desired storage stability and the desired slight change the viscosity over the temperature is achieved in the pastes according to the invention. This is apparently due to a synergistic interaction of the special solids with the other components of the damping medium in the specific proportions. The synergistic effect may be due to this on that the solids found have a high specific surface and thus a high surface activity. The damping medium according to the invention has a particularly good stability of the viscosity over the temperature and a good paste stability during storage and when used in the damper. With the damping media according to the invention, even with very long storage times and also with high pressure loads, there is no separation or precipitation of a mixture component. The high storage stability is surprisingly also given for the damping media, which contain a mixture of light or graphite-free solids and graphite. Apparently, a stabilizing effect occurs here, which may be caused by the interlocking of the solids. There are no environmental problems when processing the light-colored solids, and the risk of contamination is much lower than when graphite is used as the sole solid.

If a silicone oil is used as the base material for the liquid phase, the viscosity of the silicone oil is preferably at least 100 to 2000 mm ² / s, in particular 200 to 1000 mm ² / s at 25 ° C. The methyl and / or methylene phenyl polysiloxanes and the fluorinated silicone oils are particularly preferred. When silicone oil is used as the liquid phase, it is not necessary to add the wetting agent and C-structure viscosity agent. Obviously, there is a special inter-particulate effect between the silicone oil with low surface tension and the added solid with high surface activity. ZnS, CaF ₂ , aluminum phosphate, aluminum polyphosphate and / or calcium phosphate are particularly suitable as solids, these solids optionally being additionally mixed with graphite. When using ZnS as the base solid in a mixture with one of the other solids above, the ratio of ZnS to the other solid is generally about 2: 1. The silicone pastes above also demonstrate when used in shock and vibration dampers Continuous load at approximately 20 to 150 ° C has an approximately constant (linear) damping force curve.

If a polyglycol is used as the base material for the liquid phase, the viscosity of the polyglycol is preferably at least 20 mm ² / s at 50 ° C., in particular 20 to 200 mm ² / s at 50 ° C. Polyglycol ethers and / or esters are preferably used which are water-insoluble or only to a very small extent water-soluble. When using medium-viscosity polyglycol ethers or polyglycol ether mixtures, the viscosity is approximately 70 to 90 mm ² / s, in particular approximately 80 mm ² / s at 50 ° C. When using highly viscous polyglycol ethers or polyalkylene glycol ethers, the viscosity is approximately 170 to 200 mm ² / s, in particular 180 mm ² / s at 50 ° C.

A preferred polyalkylene glycol ether is, for example, the polyglycol ether LB 1800 (Unioncarbide). The polyglycols used according to the invention have a pour point between approximately -50 ° C. and 0 ° C., in particular between -40 ° C. and -10 ° C., and have a relative average molecular weight of approximately 700 to 20,000, in particular approximately 1 100 to 3,800.

Polyglycols with an average molecular weight of approximately 1 100 to 2 300 are particularly preferred.

However, it is also possible to use hydrophilic polyethylene, polypropylene and polybutylene glycols and mixtures thereof, and also branched polyglycols and polyglycols which are derived from glycerol,

Suitable polyglycol ethers are, for example, the polyethylene glycol monoethyl ether, propyl ether, butyl ether and pentyl ether, the polypropylene glycol monomethyl ether, ethyl ether, propyl ether, butyl ether and pentyl ether, and the polybutylene glycol mononethyl ether, ethyl ether, propyl ether, butyl ether,. -pentyl ether and -hexyl ether and the mixtures thereof.

Furthermore, the monoesters of the polyglycols can also be used, in particular the monoesters and diesters of stearic, oleic and lauric acids of the above polyglycols.

A saturated, aliphatic ester, for example the ester of a saturated, aliphatic monohydric or polyhydric C ₅ -C ₁₂ alcohol with saturated aliphatic C ₅ -C ₁₂ monocarboxylic acids, can also be used as the liquid phase. The di- and triesters of saturated aliphatic carboxylic acid esters are particularly preferred. In the case of aromatic diesters, the esters of aliphatic, saturated mono- or polyvalent C ₅ -C ₁₂ alcohols with phthalic, terphthalic and isophthalic acid are suitable. In the case of aromatic triesters, the esters from the aliphatic, saturated mono- or polyvalent C ₅ -C ₁₂ alcohols with benzene tricarboxylic acid can be used. The following esters, for example, have proven particularly suitable: esters of pentaerythritol, trimethylolpropane and trimethylpropanol with simple or branched C ₅ -C ₁₂ carboxylic acids, the esters of adipic acid, such as

Octyldecyl adipate and its derivatives, the esters of glutaric and / or pimelic acid, the esters of phthalic acid, such as diethylhexyl phthalate, dioctyl phthalate, diisotridecyl phthalate, didecyl phthalate, esters of trimellitic acid, trimesic acid and / or hemimellitic acid play tridecyl and trictyl esters of trimellitic acid.

In particular, graphite-free solid is added to the liquid phase. The solids are present in an amount of 2o to 8o% by weight, preferably 3o to 7o% by weight, based on the total weight of the damping medium. If the amount of filler is less than 20% by weight, the damping medium becomes too thin, so that it can hardly be used as an effective damping medium. When using more than 80% by weight

Fillers form a mass that is already so solid that the flowability is impaired. The preferred range of solid additives is about 30 'to 60% by weight, based on the total weight of the damping medium.

Finely divided solids which have a favorable effect on the structural viscosity of the damping medium, such as aluminum oxide, aluminum hydroxide, alurainium carbonate, aluminum phosphate, aluminum polyphosphate, aluminum silicate, cryolite, barium sulfate, calcium carbonate, magnesium oxide, magnesium carbonate, magnesium silicate, magnesium aluminum silicate, lithium stearate sulfate, magnesium stearate sulfate, magnesium stearate sulfate, magnesium stearate sulfate Silicon dioxide, sillimanite, titanium dioxide, zinc sulfide, zinc pyrophosphate, talc, kaolin and / or

Polytetrafluoroethylene. A particularly suitable solid is ZnS, optionally in combination with A1P0., Al ₅ (P ₃ O ₁₀ ) ₃ or CaF ₂ .

The light-colored solids have a particle size of 80% at most 10 μm. The preferred particle size range of the solids is 80% <5 μm, in particular 80% <3 μm. The fine distribution of the solid particles is an essential feature of the paste according to the invention, since, in addition to the other factors, it contributes to the colloidal stability of the paste. The advantageous use of light-colored fillers is explained in more detail below using the most important fillers:

ZnS and CaF ₂ have good lubricity and good temperature stability, so that the damping medium according to the invention thus produced also has a correspondingly good lubricity and good temperature stability. Kaolin has very good thickening properties, so that the total amount of solid can be reduced and a high energy conversion can still be achieved with the steaming medium. Calcium carbonate as a filler is very easy to disperse, and this improves the workability of the steaming medium.

The use of aluminum oxide increases the temperature stability of the damping medium. By using zinc sulfide as a solid, the pressure resistance of the damping medium according to the invention can be increased, and moreover, the dispersibility of the solids is improved. This is particularly important if a solid mixture is used.

Barium sulfate is a very cheap and completely inert raw material and is therefore particularly suitable for the production of rubber-friendly damping media. Molybdenum sulfide is used in particular as an additive if the lubricity of the damping medium and possibly the dispersibility of the solids are to be improved. Even small amounts of molybdenum sulfide effectively improve the lubricity of the damping medium. Molybdenum sulfide is used in particular in combination with aluminum oxide, CaF, ZnS, cryolite or graphite. Titanium oxide is used particularly when a high lightening of the damping medium and an inert behavior towards rubber parts is desired. The purity of the titanium dioxide should preferably be at least 99%.

The paste-like steaming media according to the invention have a viscosity of about 100,000 to 4 × 10 ⁶ mPa s, in particular of about 150,000 to 3 × 10 ⁶ mPa s at 18 ° C.

According to one embodiment of the invention, the solids can also be surface-treated. Some of the solids used are preferably used in silanized form.

Some of the light-colored solids can also be replaced by natural or electro-graphite, the size of the particles in particular

80% is less than 10 μm, in particular 80% less than 3 p. The light-colored solids can be replaced by graphite up to 50, especially 40 wt. The. Solid mixture preferably contains a proportion of 5 to 35 wt .-% graphite, if graphite is used as a solid.

The wetting agents or "agents for increasing the interfacial activity are used in particular at 0.5-2% by weight, based on the total weight of the damping medium, amine salts of oleic acid, linoleic acid, palmitic acid and / or stearic acid being used in particular Particularly effective wetting agents are also the organic compounds containing perfluoroalkyl groups, for example the fluorinated alkyipolyoxyethylene ethanol To improve wetting of the solids used with the liquid phase. When using silicone oil as the liquid phase, the use of a wetting agent is generally not necessary. This does not exclude that special wetting agents can be used if necessary, since there is no general incompatibility with silicone oils.

To increase the intrinsic viscosity or to stabilize the intrinsic viscosity, the damping medium according to the invention preferably contains 1 to 7, in particular 2 to 4% by weight of Al and / or Mg silicates and / or silicon dioxide in finely divided form. Highly risk silicic acid, asbestos and Ca and Na bentonites are particularly suitable. The benthonite is preferably processed in the presence of an activator, such as propylene carbonate, acetone or acetonitrile. The grain size of the used

Viscosity stabilizer is at most 0.5 μm, in particular 0.1 μm. When using silicone oil as

Liquid phase and silicon dioxide as a solid or one of the other solids is the addition of an agent for

Improvement in the structural viscosity is not necessary.

To stabilize the liquid phase against oxidation at elevated temperatures, the damping medium according to the invention, which contains esters or glycols as the liquid phase, contains 01 to 4, preferably 0.5 to 3% by weight of an antioxidant, based on the total weight of the damping medium. Suitable antioxidants are, for example, phenol and thiophenol compounds, as described in Ullmann's Encyclopedia, 15th volume, pages 217 to 220. Particularly suitable are sterically hindered amino and phenol derivatives, for example diphenylamine, phenyl-naphthylamine, thiophenylamine, alkylphenols, di-tert-butyl-p-cresol or trimethyldiheteroquinoline. When using carboxylic acid esters as the liquid phase, it can be advantageous to add a polymeric viscosity improver to improve the viscosity index and to adjust the viscosity of the liquid. These are polymers which are soluble, partially soluble or at least very readily distributable in the saturated, aliphatic or aromatic carboxylic acid esters. Suitable viscosity improvers for the damping media according to the invention are, for example, polyisobutylenes, polymethacrylates, polybutadienes, polybutenes, polypropylenes, polyethylenes and / or polystyrenes.

The above-mentioned viscosity improvers are preferably used in an amount of 0.5 to 5, in particular 0.5 to 2,% by weight, based on the total weight of the damping medium.

When using polyglycols or silicone oils as the liquid phase, the use of a viscosity improver is generally not necessary, since these compounds are available in the corresponding viscosity ranges. However, it is not excluded to use additional viscosity improvers for special applications even when using these compounds. In this case too, the viscosity improvers are used in an amount of about 0.5 to 5, in particular 0.5 to 2,% by weight, based on the total weight of the damping medium.

The damping media according to the invention are produced by introducing the liquid phase and, if necessary, mixing it with the wetting agent and optionally with the antioxidant. Then the agent for stabilizing the intrinsic viscosity, where it is required, is mixed in at 40 to 100 ° C., preferably 60 to 80 ° C., until a homogeneous distribution is achieved. Then the light solids or Geπisch made of light solid and graphite added in small proportions. When mixing the fillers, the temperature is preferably set to about 60 to 80 ° C. The stirring or mixing can also be carried out with simultaneous grinding if the introduced solids are not distributed finely enough. The steaming medium is preferably stirred or ground under vacuum in order to prevent air from being stirred into the steaming medium. Suitable stirring devices are, for example, effective dispersing machines and kneading machines, such as double kneaders, three-roll mills and planetary mixers. Depending on the mixing efficiency of the stirrer, the mixing time is about 20 to 120 min. A homogeneous, storage-stable paste is obtained. Even with storage times of several months, the solids or a solid does not settle.

The damping media according to the invention are suitable for hydraulically acting damper devices, in particular as media for engine mounts, wheel dampers, impact dampers, steering dampers, shock absorbers, devices for rail vehicles and airplanes, vibration dampers of all kinds, seat dampers and for the vibration-free mounting of machines.

The invention is illustrated by the following examples.

example 1

A homogeneous damping medium was produced in which the

Carboxylic acid ester was mixed with the wetting agent and the antioxidant. The viscosity structure stabilizer was then mixed in at 60 ° C., and after a stirring time of about 20 minutes. the fillers stirred in. The composition of the damping medium is summarized in the following table:

% By weight

Trimethylpropane octyl decyl ester 50

Graphite (particle size less than 0.8 μm) (filler) 1 6

Zinc sulfide (filler) 30

Fluorinated Al kylpσlyoxyäthylenäthanol (wetting agent) 1

Amorphous silicon dioxide (particle size below

0.1 μm) 2

Diphenylamine (antioxidant) 1

In a further experiment, the above ester was replaced by the trimethyladipic acid didecyl ester. Both pastes showed an oil separation of less than 1% in the sieve test (DIN 51817) at 24 h at 100 ° C. Example 2

A damping medium according to the method of Example 1 was produced with the following composition:% by weight

Polyglycol monobutyl ether (viscosity 80 qmm / s at 50 ° C) 50

Graphite (particle size <3 μm) 14

ZnS 32.5

Alkyl polyoxyethylene ethanol (fluorinated) (wetting agent) 0, 5

Phenyl-α-naphthylamine (antioxidant) 1

*) Bentonite with propylene carbonate as activator 2

*) Propylene carbonate content: 0.5% by weight

Example 3

A damping medium was produced according to the method according to example 1 with the following composition:

% By weight

Polyglycol monobutyl ether (viscosity 80 qmm / s at 50 ° C. 50

Graphite (particle size <3 μm) 41.8

Tetrafluoroethylene (particle size <5 μm) 4.7

Fluorinated alkyl alkoxylate (wetting agent) 0.5

*)

Bentonite with propylene carbonate as activator 2

Trimethyldiheteroquinoline (antioxidant) 1

*) Propylene carbonate content: 0.5% by weight Example 4

A damping medium according to the invention was produced using the method according to Example 1 with the following composition:

% By weight

Didecylazelate 32, 8

Zinc sulfide (solid) grain size <2 μm 46

Graphite particle size <3 μm 16, 7

Alkyl polyoxyethylene ethanol (wetting agent) 0, 3

Di-tert. -butyl-p-cresol (Zmcictxidationsmittel) 0, 4

Bentonite (Bentone) with 20% propylene carbonate as activator 1, 8

Polymethacrylate (viscosity improver) 2

Example 5

A homogeneous paste was produced by introducing a silicone oil of a certain viscosity, into which the solids were then carefully stirred or kneaded. The composition of the damping medium is summarized below:

% By weight

Dimethylpolysiloxane (viscosity 350 m ² / s) 31.5

ZnS (particle size <2 µm) 42.0

CaF ₂ (particle size <2 μm) 26.5 penetration (DIN 51804): 260 to 280 · 0.1 mm oil separation (DIN 51817 but when heated to 100 ° C for 24 h): 0.2% by weight Example 6

A damping medium with the following composition was produced by the process described in Example 5:

% By weight

Dirnethylpolysiloxane (viscosity 350 m ² / s) 36.0

Graphite (particle size <3 μm) 14.0

ZnS (particle size <2 μm) 50.0

Penetration (DIN 51804): 260 to 280 x 0.1 mm

Oil separation (DIN 51817 but when heated to 100 ° C for 24 h): 0.5% by weight

Example 7

A damping medium with the following composition and the properties specified below was produced by the process described in Example 5:

% By weight

Dimethylpolysiloxane (viscosity 350 m / s) 40.4

ZnS (particle size <2 µm) 38.5

Aluminum phosphate (AlPO ₄ · 2H ₂ O) with a high specific surface area 21.1

Penetration (DIN 51804): 260 to 280 x 0.1 mm

Oil separation (DIN 51817 but when heated to 100 ° C for 24 h): 0.2% by weight Application example

The damping medium according to the invention (e.g. according to Example 4) was filled into a hydraulically acting impact damper, which consisted of two concentric tubes, the inner tube forming the piston and the outer tube forming the cylinder. The inner tube contains a nitrogen filling, which is kept from the piston crown behind by a separating piston. The Kölbenboden is drilled. The damping medium is located in the cylinder space behind the bottom of the Kölben and penetrates through the bore into the inner tube when it is pressed into the outer tube on impact. The damping medium pushes back the separating piston and compresses the enclosed gas filling. The spring force of the gas ensures that the two pipes are returned to their original position after the impact has ended. A control pin protrudes into the bore in the bottom of the piston. The control pin has a conical shape, but is achieved in steps of about 1/10 mm. The further the pin penetrates into the bore, the smaller the gap that is available for the damping medium to flow through. As a result, a targeted increase in force can be achieved towards the end of the damper path.

Due to the viscosity of the damping medium according to the invention, it is possible to keep the tolerances in the damper device larger than is the case with conventional series dampers with hydraulic oil. The damping medium does not foam at high pressure differences and has a flash point of more than 300 ° C.

The impact absorber was attached to the front of a motor vehicle with a weight of 475 kg.

To determine the compression path, an inductive displacement sensor was firmly attached to the vehicle and with connected to the top of the impact damper. In addition, an accelerometer was attached to the vehicle, which recorded the vehicle deceleration. Several impact tests were carried out under the following test conditions:

Vehicle mass 450 kg and impact speed 5.3 km / h Vehicle mass 475 kg and impact speed 7.9 km / h

The force-displacement diagram for the above impact tests shows an almost rectangular shape and thus optimal damping behavior. The entire kinetic energy of the vehicle is absorbed by the damper, and the available path (stroke) is optimally used (see FIGS. 1 and 2). FIG. 1 shows the force-displacement diagram for the impact test with a load of 450 kg at 5.3 km / h and FIG. 2 shows the impact test with a load of 475 kg at 7.9 km / h.

Even at an impact speed of 10 km / h, the shock does not break through. The vehicle deceleration (vehicle mass 500 / kg) is 9.8 g and thus far below the deceleration that is achieved with conventional impact dampers that are filled with hydraulic oils. The energy consumption in the impact damper filled with the damping medium according to the invention is therefore considerably greater than in the case of the usual impact dampers.

While only a part of the impact energy is converted and the rest is stored like a spring in the conventional impact dampers, which are filled with hydraulic oils, and then the vehicle then throws them back, in the case of the impact dampers filled with the damping media according to the invention, practically all of the kinetic energy dismantled on impact. The vehicle does not rebound.

Claims

1. Paste-like damping medium for damping mechanical and / or acoustic vibrations based on a liquid phase and at least one finely divided solid, characterized. that there is about 20 to about 80 wt .-% aluminum oxide, silica, hydroxide, carbonate, phosphate, polyphosphate, cryolite barium sulfate, calcium carbonate, hydroxide, phosphate, fluoride, magnesium oxide, carbonate, silicate, aluminum silicate, stearate, lithium stearate,

Molybdenum sulfide, silicon dioxide, sillimanite, titanium dioxide, zinc sulfide, talc, kaolin, zinc pyrophosphate and / or polytetrafluoroethylene with a particle size of 80% <10 μm, based on the total weight of the damping medium, and silicone oil, polyglycol or a, temperature-resistant, saturated, aliphatic or aromatic: contains carboxylic acid esters.

2. paste-like damping medium for damping mechanical and / or acoustic vibrations based on a liquid phase and at least one finely divided solid, characterized in that it is about 20 to 80% by weight, based on the total weight of the damping medium, of a mixture of aluminum oxide, hydroxide, carbonate, phosphate, polyphosphate, silicate, cryolite, barium sulfate, calcium carbonate, hydroxide, phosphate, fluoride, magnesium oxide, carbonate, silicate, aluminum silicate, stearate, lithium stearate, molybdenum sulfide, silicon dioxide,

Sillimanit, titanium dioxide, zinc sulfide, zinc pyrophosphate and orPolytetrafluoräthylen a particle size of 80% <10 microns and graphite of a particle size of 80% <10 microns and silicone oil, polyglycol or contains a temperature-resistant, saturated, aliphatic or aromatic carboxylic acid ester.

Damping medium according to claim 1 or 2, characterized in that it additionally contains about 0.1 to 4% by weight of wetting agent and / or about 0.5 to 10% by weight of finely divided magnesium silicates, aluminum silicates and / or Contains silica as shear thinning stabilizers, based in each case on the total weight of the damping medium.

4. damping medium according to claim 1 or 2, characterized in that the solid or the solid mixture in an amount of 30 to 70 wt .-%, based on the total weight of the damping medium, is present.

5. damping medium according to claim 1 or 2, characterized in that the particle size of the solids is 80% <5 microns, in particular 80% <3 microns.

6. damping medium according to claim 2, characterized in that the solid mixture contains at most 50 wt .-% graphite, in particular at most 40 wt .-% graphite.

7. damping medium according to claim 1 or 2, characterized in that it contains 0.5 to 2 wt .-% wetting agent or agent for increasing the interfacial activity, the wetting agent in particular an amine salt of oleic acid, linoleic acid, palmitic acid and / or stearic acid, Taig fatty acid diamines, coconut fatty acid diamines, naphthalene sulfonates, alkylarylsulfonates, fatty alcohol polyglycol ethers, ethoxylated acetylene alcohols, alkyl compounds containing perfluoroalkyl groups, fluorinated alkylpolyoxyethylene ethanol, potassium fluoroalkyl carboxylate and / or fluorinated alkyl ammonium iodide.

8. damping medium according to claim 1 or 2, characterized in that it contains 1 to 7 wt .-%, in particular 2 to 4 wt .-%, of the shear thinning stabilizer, based on the total amount of the damping medium.

9. steaming medium according to claim 1 or 2, characterized in that it is 0.1 to 4 wt .-%, in particular 0.5 to 3 wt .-%, based on the total weight of the steam mediums, contains antioxidants for the polyglycols or carboxylic acid esters, the antioxidants in particular a sterically hindered alkylphenol. Thiophenol or dialkyl selenide / especially diphenylamine, phenyl-α-naphthylamine, methylene-4,4'-bis (2,6-di-tertiary-butylphenol), thiophenylamine, di-tertiary-butyl-p-cresol or trimethyl diheteroquinoline is.

10. damping medium according to claim 1 or 2, characterized in that it contains 0.5 to 5 wt .-% of a polymeric viscosity improver as an additional additive, based on the total weight of the damping medium, the viscosity improver in particular a polyisobutylene, polymethacrylate, polybutene, -butadiene, polyethylene, polypropylene and / or polystyrene.

11. Damping medium according to claim 1 or 2, characterized in that the shear thinning stabilizer is a Ca-concreteite, Na-concreteite, asbestos and / or highly disperse silica.

12. damping medium according to claim 1 or 2, characterized in that the liquid phase consists of a silicone oil of viscos from 100 to 2000, in particular 200 to 1000 mm ² / s at 25 ° C, preferably of dimethylpolysilixane, phenylmethylpolysiloxane and / or fluorinated polysiloxane.

13. damping medium according to claim 1 or 2, characterized in that the liquid phase consists of silicone oil and the solid of zinc sulfide, CaF ₂ , aluminum phosphate, calcium phosphate and / or graphite.

14. A process for the preparation of the damping medium according to claim 1 or 2, characterized in that the liquid phase at temperatures of 40 ° C to 100 ° C, in particular 60 ° C to 80 ° C, optionally with. mixed with the wetting agent and optionally with the antioxidant, optionally admixing and swelling the intrinsic viscosity stabilizer and then the

Solid fillers are mixed in small proportions until a homogeneous paste is obtained.

15. Use of the damping medium according to one of claims 1 to 13 in impact dampers, wheel dampers, steering dampers, seat dampers, engine dampers, machine mounting dampers, industrial shock absorbers or industrial vibration dampers.