SE415887B - Pasty sound-insulating dispersion based on a liquid phase and graphite - Google Patents

Abstract

The invention relates to a pasty viscous sound-insulating dispersion based on a liquid phase and graphite. The dispersion contains a substance for raising its structural viscosity and at least one wetting agent to wet the graphite in it. The dispersion obtained is free- flowing over a very wide temperature range, does not set under a load and remains viscous. The said dispersion has sound-insulating properties. Furthermore, the dispersion according to the invention does not make elastomers swell.

Description

7907 89¿ + ~ 5 (Abbott et al) known an attenuator which contains a petroleum oil and in which up to 20% of a particular montmorillonite clay is dispersed. The composition and properties of this damping agent are not comparable to the particular composition of the highly viscous dispersion according to the invention. In addition, the known damping agent causes swelling of elastomers, which leads to the elastomeric parts of the damper being degraded at an early stage.

It was therefore desired to obtain a damping agent dispersion which does not form foam under continuous load, exhibits good thermal conductivity, is self-sealing and does not cause swelling in elastomers based on natural rubber or natural rubber / isoprene. The damping agent must exhibit a constant damping both for shocks and for vibration oscillations both at lower and also at higher temperatures and also at continuous loading. It should absorb the energy from shock loads with higher and also lower frequency and convert it into heat. The damping agent must not be hardened in the event of a sudden shock load, as it must also have a sound-absorbing effect, especially for the so-called body sound ("body sound"). Furthermore, it is desirable that the dispersion is sound-insulating.

An essential task in connection with the invention lies in the fact that the elastomeric parts included in any damper, for example motor bearings, should not be exposed to swelling.

The objects of the invention are thus paste-like, viscous suppressant dispersions, which are characterized in that they contain polyglycol ethers and / or esters and optionally saturated, aliphatic or aromatic carboxylic acid esters, ground graphite; at least one wine component and an agent for increasing the structural viscosity, eg silicon compound and / or aluminum silicate. As the liquid phase in the dispersion, hydrophobic polyglycol ethers and / or esters are preferably used, which are insoluble or to a very small extent soluble in water. The polyglycol ethers and / or esters have a viscosity of about 10 mma / s to 4000 mm 2 / s at 5000, in particular about 20 to 500 mm 2 / s at 50%. In case low viscosity polyglycol ethers and / or esters are used, the viscosity of the ether used and the mixture, respectively, is about 50-50, in particular 40, mm 2 / e at 50 ° C. An advantageously used, low-viscosity polyalkylene ether mixture is, for example, the polyglycol ether 0 Hoechst "VP 15 65/40" and / or Union Carbide "LB 500".

When using hydrophobic, medium-viscous polyglycol ethers or polyglycol ether mixtures, the viscosity amounts to about 70-90, in particular about 80, mm2 / s at 50 ° C. Preferably the polyalkylene glycol ether Hoechst "B 01/80" and / or "LB 625" from Union Garbide is used.

When using hydrophobic, highly viscous polyglycol ethers and polyalkylene glycol ethers, respectively, the viscosity # 111 amounts to about 170 sin zoo mmz / e, in particular 180 mmz / s at 50 ° C.

An advantageously used polyalkylene glycol ether is, for example, the polyglycol ether "LB 1800" from Union Carbide.

The polyglycol ethers and / or esters used according to the invention have a solidification point of preferably about -50 to 0 ° C, in particular between -40 and -10 ° C.

The hydrophobic polyglycol ethers and / or esters used according to the invention have a relative average molecular weight of about 700 to 20,000, in particular about 1,100 to 5,800, preferably about 1,100 to 2,500.

The polypropylene glycol monopropyl ethers preferably have a viscosity of 500 to 10,000 mm 2 / s at 50 ° C, a relative average molecular weight of about 5,000 to 20,000 and a solidification point (DIN 51550) of about -10 to ÉO. The preferably used polypropylene glycol monobutyl ethers have, for example, a viscosity of 50 to 700 mm 2 / s and 20 to 240 mm 2 / s, respectively, at 50 ° C, a relative average molecular weight of about 1,200 to 5,800 and about 700 to 2,500, respectively, and a solidification point ( DIN 51585) of -5o to -55 ° c and -5o to -4o ° c, respectively.

For the damping agent dispersions according to the invention, the polyglycarbon monb and / or dieters of polyethylene, polypropylene or polybutylene glycol are particularly suitable. The ether groups in the mono- and / or dieters consist of saturated, straight or branched alkoxy groups having 1 to 10 carbon atoms, in particular 2 to 6 carbon atoms. Particularly suitable are, for example, polyethylene glycol monoethyl ether, propyl ether, butyl ether and pentyl ether, polyethylene glycol monoethyl ether, ethyl ether, propyl ether, butyl ether and pentyl ether and polybutylene glycol monomethyl ether, ethyl ether, ethyl ether , -pentyl ether and -hexyl ether and mixtures thereof. Furthermore, the hydrophobic polyglycol mono- and / or diesters of polyethylene, polypropylene or polybutylene glycols and the monoesters of polyglycol ethers are also suitable for the paste-like suppressant dispersions according to the invention. Of particular importance are, for example, the monoesters and diesters of stearic acid, oleic acid and lauric acid with the polyglycols given above. By choosing the polyglycol type with longer or shorter chains, one can affect the ichlorophilic-lipophilic equilibrium of the ester. The diesters are generally stronger lipophilic than the monoesters. The polyglycol ethers and / or esters according to the invention are preferably used in an amount of about 40 to 70% by weight, in particular 50 to 60% by weight, based on the total weight of the dispersion.

In addition to the polyglycol ethers and / or esters, the damping dispersion according to the invention may also contain a silicone oil with a viscosity of about 10 mma / s to 1,000 mm? s at 50 ° C, the methyl and / or methylphenylsilicone oils in particular being found to be suitable.

Furthermore, mineral oils with a viscosity of about 10 mm 2 / s to 1,000 mm 2 / s at 50 ° C, preferably at least about 50 m 2 / s at 50 ° C and a flash point of at least 160 ° C can also be used.

An example from this group is machine oils with a viscosity of 100 to 200 mm? / S at 20 ° C and a flash point of 190-22000 (DIN 51515).

In connection with the aliphatic, saturated carboxylic acid esters which may be used as a supplement, for example, the esters of saturated, aliphatic, monohydric or polyhydric C1-C12-alcohols with saturated aliphatic 05-C12 monocarboxylic acids are suitable.

Among the aliphatic saturated dicarboxylic acid esters, the esters of saturated, aliphatic, monovalent or polyvalent 05-01z-alronols with saturated, aliphatic hydraulic acid-aika1-bmylcylic acids are particularly suitable. Among the aromatic dicarboxylic acid esters, the esters of aliphatic, saturated, monohydric or polyhydric G5-C12 alcohols with phthalic acid, terephthalic acid and isophthalic acid are particularly suitable. Among the aromatic tricarboxylic acid esters, the esters of the aliphatic, saturated, monohydric or polyhydric 05-C12 alcohols with benzotricarboxylic acid are particularly suitable.

The amount ratio between the liquid phase and the graphite should be adjusted relative to each other according to the desired viscosity of the dispersion. A high viscosity necessitates a higher content of graphite. The amounts of graphite used also depend on the particle size of the graphite used. At a certain viscosity, the proportion of liquid phase is larger, the larger the graphite particles used are. By selecting the graphite particle size and / or the amount of graphite, the viscosity of the dispersion can be adjusted within certain ranges.

The liquid phase used according to the invention is added with graphite of leaf-shaped and / or spherical structure. The particle size of the graphite should not exceed 100 .mu.m, in particular not more than 50 .mu.m. Suitably graphite having a particle size of 5 to 10 μm is used. However, mixtures of graphite particles with different particle sizes can also be used. The amount of the graphite added is 50 to 70% by weight, in particular 55 to 60% by weight, based on the total weight of the dispersion. The preferred amount of graphite is 40 to 60% by weight, based on the total weight of the dispersion.

The damping dispersion according to the invention contains at least one wetting agent, which prevents solid particles from settling in the dispersion. The wetting agents are added in an amount of about 0.1 to 8% by weight, in particular 0.5 to 6% by weight, preferably 1.5 to 5% by weight, based on the total weight of the dispersion. In this case, the amount utilized in each individual case depends on the diameter of the graphite particles.

The larger the graphite particles, the less wetting agent is used. In particular, wetting soaps are used as wetting agents, whereby amine soaps of the fatty acids have proved to be particularly suitable. Suitable are, for example, the amine compounds of tallow fatty acid, stearic acid, palmitic acid, linoleic acid and / or oleic acid, for example tallow fatty acid diamine, coconut fatty acid diamine and / or oleic acid diamine. It is advantageous to add the dispersion according to the invention with stabilizing dispersions. turquoise viscosity. Suitable are, for example, amorphous silica and finely ground aluminum silicates, especially organophilic bentonite materials.

The agents for increasing the structural viscosity preferably have a grain size of less than 0.5 .mu.m, in particular about 0.1 .mu.m. The added amount of the agent which supports the structural viscosity is in a range from about 0.1 to 10, in particular 0.5 to 5, preferably 1 to 2% by weight, based on the total weight of the dispersion. Furthermore, additives of finely ground asbestos have also proved to be suitable. The damping agent dispersions of the invention may optionally additionally contain anti-doping agents. The amount of antioxidant may, for example, be at least 0.1% by weight, calculated on the total weight of the dispersion. Suitable are, for example, phenol and thiophenol compounds of the type described in Ullmann's Encyclopedia, Volume 15, p. 21? 220. Particularly suitable for use in the dispersions according to the invention are the sterically hindered amino and phenol derivatives, for example diphenylamine, phenyl-oc-naphthylamine and / or phenothiazine.

The attenuator dispersions according to the invention using hydrophobic polyglycol ethers and / or esters do not tend to foam up under continuous loading, as they have a very good thermal conductivity. The thermal conductivity of the damping agent dispersions according to the invention is 2 to / +, in particular 2 to 5.5, calories / cm x s x OC.

The damping agent dispersions according to the invention are self-sealing, resistant to the action of mineral oil and they also have an extremely good viscosity stability over a wide temperature range. The dispersion does not harden in the event of a sudden shock load but remains plastic and viscous. The viscosity of the dispersions according to the invention is at oa 1 - 11- x 106 cP at 2500, in particular at 1.5 to 5 x 106 CP via 25%. Even under heavy load of the evaporator at high speed, for example when using the dispersion in an elevator damper or in a shock absorber, the dispersion does not harden and it remains free-flowing and homogeneous. It is important that the free-flowing ability is maintained even at temperatures below 0 ° C.

The viscosity and the plastic behavior, ie the rheology of the dispersion, change only insignificantly when the dispersion is heated at normal pressure to temperatures of up to 500 ° C. When the dispersion is under pressure, the temperature load can also be increased for a short time to 40,000, without changing the damping curve of the damping dispersion according to the invention.

A very essential property of the dispersion according to the invention is that it does not separate even at continuous compressive and / or tensile loads, ie that the solids in the dispersion do not settle.

The damping dispersions according to the invention are age-resistant and are neutral to elastomers, in particular to elastomers based on natural rubber or synthetic rubber. The rubber parts in the damper which are in contact with the damping agent dispersions according to the invention do not swell by the action of the dispersion, whereby the service life of the corresponding rubber parts is substantially increased.

In addition, the damping agent dispersion according to the invention has the advantage that it absorbs shock loads with large amplitudes as well as with smaller amplitudes, ie the kinetic energy is converted into frictional heat, which is quickly dissipated. An essential property of the damping dispersion according to the invention lies in the fact that body sound oscillations are not transmitted through the dispersions, ie the dispersion according to the invention has a sound-insulating effect.

The non-Newtonian damping agent dispersion according to the invention is further illustrated by the following examples, without the invention being limited to these examples.

Example 1 The polyalkylene glycol ether, tallow fatty acid diamine and diphenylamine were mixed well, then the organophilic bentonity was mixed and the graphite was then incorporated under pressure by means of a roller mill until the dispersion was homogeneous. 7907894-s Ingredients Weight percent Polyalkylene glycol ether (polypropylene glycol monobutyl etherà Hoechst "VP 1565/40", viscosity 40 mm / s at 50 ° C) 50 Tallow fatty acid diamine (wetting agent) 5 Diphenylamine (antioxidant) 2 Organophilic bentonite ("Bentone 54": Gesellschaft) 1 Natural graphite, purity 99%, particle size max 5 / um 44 According to DIN 55 521, 5 plates (2 mm thick) and 2 plates (6 mm thick) of vulcanized raw rubber were stored 140.11 = in 40 Shore and 16 6.11 = 60 Shore in the above-mentioned damping agent dispersion for 72 hours at room temperature and 72 hours at 100 ° C, respectively. The elastomer plates were then taken out of the dispersion, rinsed off and weighed. The elastomeric plates did not show any weight gain and were not swollen.

During pressure storage of the dispersion at 40 ° C for 14 days - according to IPI 121 according to the American Petroleum Institute, a liquid volume of 0.8 96 was separated.

The dispersion remained wid: a cutting speed of up to ll- m / sec. free-flowing, homogeneous and did not show any signs of decay. Higher cutting speeds were not previously investigated.

There is reason to believe that the dispersions according to the invention can be loaded with cutting speeds of up to 8 m / sec.

The antioxidant can also be omitted without the rheological properties of the dispersion being thereby adversely affected.

Example 2 Ingredients Weight percentage Hydroium polypropylene glycol monobutyl ether Hoechst "B 83/80", viscosity 80 mmN / sec. at 5 Q) 55.5 Coconut fatty acid diamine (wetting agent) 4 Phenyl-α-naphthylamine (antioxidant) 2 Organophilic bentonite 1 Natural graphite, purity 99 96, particle size max. 5 .mu.m - 57.5 According to DIN 55521, strips of vulcanized raw rubber were tested as in Example 1. The strips did not show any weight gain and were not swollen.

Example gel 2 Ingredients Hydrofcb polyalkylene glycol ethers (viscosity: IBO mm / s at 50 ° C, Union Carbide "LB 1800") Oil acid diamine (wetting agent) Organophilic bentonite Natural graphite, purity 99.5%, particle size 5 to % by weight 54 5 2 ll-'l Strips of vulcanized raw rubber were immersed (according to DIN 55 521) in the dispersion indicated above and stored in this dispersion for 72 hours at 10000. The strips were then taken out of the dispersion, cleaned and weighed. The strips did not show any weight loss and were not swollen.

If desired, the dispersion described above can also be: Replaced with 1 to 2% by weight of an antioxidant (eg phenothiazine), without adversely affecting the rheological properties.

Claims (14)

'79 Û789lv5 10 Patentkrav Paste-like, viscous damping dispersion for attenuating mechanical and acoustic oscillations, characterized in that it contains at least one polyglycol ether and / or polyglycol ester, 50 to 70% by weight of ground graphite with a particle size below 100 .mu.m, 0,1 to 8% by weight of wetting agent and 0.1 to 10% by weight of an aluminum silicate or a silicon compound as a viscosity stabilizer, all contents being calculated on the total weight of the dispersion, and that the viscosity of the dispersion amounts to approx. l to U x 106 CP at 25 ° c. Dispersion according to Claim 11, characterized in that the polyglycol ethers and / or esters are insoluble or only to a very small extent soluble in water and have a viscosity of about 10 mma / s to 000 mmz / s at 5o ° c, in particular about no mmz / s to 500 mmg / s at 5o ° c. Dispersion according to Claim 1 or 2, characterized in that the polyglycol ethers and / or esters have a solidification point between -50 ° C and 0 ° C, in particular -11 ° C to -10 ° C, and a relative average molecular weight of about 700 to 20,000, in particular about 100 to 5,800, preferably about 100 to 2,500. Dispersion according to one or more of claims' I - 5 ,. characterized in that the polyglycol ethers consist of the mono- and / or dietary ethers of polyethylene, polypropylene or polybutylene glycols. l Dispersion according to Claim 4, characterized in that the ether group in the mono- or dieter is a saturated, straight or branched alkoxy group having 1 to '10 C atoms, in particular 2 to 6 C atoms. Dispersion according to one or more of Claims 1 to 5, characterized in that the polyglycol ether is a polyethylene glycol monoethyl ether, monopropyl ether or monobutyl ether, polypropylene glycol monoethyl ether, monopropyl ether or mono-butyl ether, polybutylene glycol ether. monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monopentyl ether 7907894 Dispersion according to one or more of Claims 1 to 5, characterized in that the polyglycol esters consist of the mono- and / or diesters of polyethylene, polypropylene or polybutylene glycols, in particular the monoesters of polyethylene, polypropylene or polybutylene glycol mono. Dispersion according to one or more of Claims 1 to 7, characterized in that the polyglycol ethers and / or esters are present in an amount of about 40 to 70% by weight, in particular 50 to 60% by weight, based on the total weight of the dispersion. Dispersion according to one or more of Claims 1 to 8, characterized in that it contains 0.5 to 6% by weight, preferably about 1.5 to 5% by weight, of wetting agent, based on the total weight of the dispersion, and that the wetting agent is preferably in addition, they consist of amines of fatty acids, in particular tallow fatty acid diamines, coconut fatty acid diamines, oleic acid diamines, linoleic acid diamines and / or palmitic acid diamines. Dispersion according to one or more of Claims 1 to 9, characterized in that the increase in structural viscosity contains about 0.5 to 5, preferably 1 to 2,% by weight of amorphous silica and / or finely ground aluminum silicate. , preferably bentonite having a particle size below 0.5 .mu.m, in particular 0.1 .mu.m, based on the total weight of the dispersion. Dispersion according to one or more of Claims 1 to 10, characterized in that the graphite content is about 55 to 60% by weight, in particular 40 to 60% by weight, based on the total weight of the dispersion, and that the graphite preferably has a particle size not exceeding 50 .mu.m, in particular 5 to 10 .mu.m. 12. Dispersion according to claim 1, characterized in that the viscosity of the dispersion amounts to about 1.5 to 5 x 10 6 cr at 25 ° C and that the heat absorption capacity amounts to 2 - 4, in particular 2 - 5.5. cal / cm s ° C. Dispersion according to one or more of Claims 1 to 12, characterized in that it additionally contains antioxidants, preferably substituted phenols or aromatic amines, in particular diphenylamine, phenyl-α-naphthylamine, phenothiazine, di -tert.-butyl-p-cresol, in an amount of at least 0.1% by weight, preferably 1 to 5% by weight, based on the total weight of the dispersion. The dispersion according to claim 1, characterized in that it further contains a silicone oil having a viscosity of at least 20 cSt at 25 ° C and / or a saturated, aliphatic or aromatic mono-, di- or tricarboxylic acid ester. The invention relates to a paste-like, viscous damping agent dispersion based on a liquid phase and graphite, the dispersion being provided with at least one agent for increasing the structural viscosity and at least one wetting agent for wetting the graphite. The dispersion described is free-flowing over a very wide temperature range, does not harden under load and remains viscous and the dispersion is sound-insulating. Furthermore, the dispersion according to the invention does not cause any swelling in elastomers.