EP0624185A1

EP0624185A1 - Homogeneous electroviscous liquids.

Info

Publication number: EP0624185A1
Application number: EP92923692A
Authority: EP
Inventors: Dietrich Pirck; Hans-Dieter Grasshoff; Harald Kohnz
Original assignee: RWE Dea AG fuer Mineraloel und Chemie; RWE Dea AG
Current assignee: Wintershall Dea Deutschland AG
Priority date: 1991-11-28
Filing date: 1992-11-30
Publication date: 1994-11-17
Anticipated expiration: 2012-11-30
Also published as: DE4294095D2; BR9206842A; AU2838095A; CA2122718C; ATE150480T1; AU2940892A; DE59208255D1; JPH07501357A; WO1993011209A1; AU670404B2; KR100209184B1; CZ287038B6; CA2122718A1; EP0624185B1; AU658949B2; JP3236296B2; RU2114904C1; DE4139065A1; CZ130994A3

Abstract

Homogeneous electro-viscous liq. contain or consist of Al soaps obtd. by reaction of (un)satd., monomeric, oligomeric and/or polymeric 3-32C polycarboxylic acid(s) with 1 or more COOH gps., or anhydrides and/or semi-esters in which the alcohol component is an (un)branched, 1-12C mono- or poly-alcohol and/or oligomer, with an Al alcoholate in which the alcohol component is an (un)branched 1-18C aliphatic mono- or poly-alcohol. The Al soaps are pref. obtd. by reaction of a 3-18C (12-18C) polycarboxylic acid, anhydride or semi-ester, esp. a 5-18C (12-18C) alkenylsuccinic acid and/or semi-ester, partic. polycarboxylic acids, anhydrides or semi-esters with free OH gps.. The alcohol component of the semi-ester is a 1-6C (2-5C) di-, tri- or tetra-ol or an oligomer. In the Al alcoholates, the valency of the Al is (partly) the same. The electro-viscous liqs. contain (a) 2-50 (10-35) wt.% of the Al soap, in homogeneous soln., (b) 50-98% (65-90%) of a conventional hydraulic base fluid, and (c) 0-10% (0.1-2%) of soluble known hydraulic oil additive.

Description

Homogeneous electroviscous liquids

The invention relates to homogeneous electroviscous liquids (EVF).

Electroviscous liquids in the form of dispersions of finely divided hydrophilic solids in hydrophobic liquids have been known for some time. The special feature of these liquids is that their flow behavior and thus their viscosity can be changed within wide limits by applying an electric field, so that there are wide-ranging and versatile possible uses. Electroviscous liquids are intended for use in particular in the field of industrial and vehicle hydraulics, e.g. for machine and engine mounting or damping, for positioning workpieces, for vehicle level control, vehicle suspension and damping as well as for torque converters and automatic clutches.

The material composition of the known electroviscous liquids is very different. As a rule, the electroviscous liquids consist of three components, a disperse phase which contains silicates, zeolites, titanates, semiconductors, polysaccharides or organic polymers, an electrically non-conductive hydrophobic liquid as the liquid phase and a dispersant. DE 35 36 934 A1 describes electroviscous liquids whose disperse phase contains aluminum silicates which have a water content of 1-25% by weight and whose atomic ratio Al / Si on the surface is between 0.15 and 0.80.

In all known electro-viscous liquids, however, since they are dispersions, there is the disadvantage that considerable proportions of additional dispersing components are required to reduce the material-related tendency to sedimentation. The suitability of the known products, particularly in long-term use, is therefore unsatisfactory in many cases for use in modern hydraulic units. In particular, conventional dispersions have technical-hydraulic disadvantages, of which only a few are mentioned below: tendency to very strong abrasion-evaporation of water of crystallization-lacking filterability for the separation of foreign substances-presence of toxic / safety-questionable

Components - incompatibility with elastomer sealing materials.

It is also known that many highly polar liquids in the high-voltage field also show certain changes in the flow behavior. However, these effects are weak and cannot be used technically. The object of the invention is therefore to provide homogeneous electro-viscous liquids which meet the technical requirements of a modern industrial hydraulic fluid and which do not have the disadvantages described, but rather have a high electro-viscous effect.

This object is achieved according to the invention by the provision of electroviscous liquids which contain or consist of aluminum soaps, which are obtained by reacting one or more saturated and / or unsaturated monomeric, oligomeric and / or polymeric polycarboxylic acid (s) with one or more carboxyl groups and 3 to 32, preferably 3 to 18 and in particular 12 to 18 carbon atoms, their anhydrides and / or half-esters, their or their

Alcohol component (s) are straight or branched, mono- or polyhydric alcohols with 1 to 12, preferably 1 to 6 and in particular 2 to 5 carbon atoms and / or their oligomers, are prepared with one or more aluminum alcoholates, the alcohol component thereof (n) one or more aliphatic, straight or branched, monohydric or polyhydric alcohols having 1 to 18, preferably 2 to 8 and in particular 2 to 5 carbon atoms.

Surprisingly, it was found that a high electrorheological effect is achieved by doping with aluminum. Completely homogeneous products are obtained.

According to the invention, the reaction products of the polycarboxylic acids, anhydrides or half esters with aluminum alcoholates are used as aluminum soaps, in which all or some of the valences of the aluminum are converted. Aluminum soaps are preferably used, which

Reaction products of the polycarboxylic acids, their anhydrides and in particular their half esters, which have one or more free OH groups, with aluminum alcoholates. The aluminum soaps are produced in particular by reacting one or more alkenylsuccinic acids and / or their half esters with 5 to 18 C atoms and preferably 12 to 18 ^' C atoms.

The electroviscous liquids according to the invention preferably comprise the following individual components:

Component (a): 2-50% by weight, preferably 5-40% by weight, in particular 10-35% by weight of the aluminum soap, in homogeneous solution with component (b): 50-98% by weight, preferably 60 -95% by weight, in particular 65-90% by weight, of a conventional hydraulic base fluid, and additionally component (c): 0-10% by weight, preferably 0-5% by weight, in particular 0.1 to 2 % By weight, soluble, known hydraulic

Additives, each based on the total composition.

Component (a) consists of oligomeric, complex aluminum soaps based on reaction adducts of polycarboxylic acids or olefinic carboxylic acids, their anhydrides, half-esters or oligomers with aluminum alcoholates. The soap formation takes place completely or partially, for example by targeted partial hydrolysis, so that hydroxyl soap structures are formed. Olefinic carboxylic acids are to be understood as meaning carboxylic acids which are formed by reacting unsaturated carboxylic acids with one another or with olefins. Such compounds are used as their oligomers, which consist of 2 to 10, preferably 2 to 6, units.

As the alcohol components of the Al-alkoxides straight and branched lower alcohols are used, in particular those with C _j to C. The alcohols are released and discharged during the reaction. In the case of reaction with anhydrides, straight-chain or branched alcohols with up to 18 carbon atoms can be used as the alcohol component, which essentially remain in the molecule of the reaction product due to addition.

Straight-chain or branched mono- or polyhydric alcohols are used as alcohol components of the polycarboxylic acid semiesters. The C number is advantageously determined by the selection of the base liquid in order to ensure the solubility of the corresponding reaction products.

Examples of component (a) are partial ester / aluminum alcoholate adducts based on alkenyl succinic anhydrides, in particular n-hexenyl succinic anhydrides, diisobutenyl succinic anhydrides, tetrapropenyl succinic acid anhydrides, dodecenyl anhydride and poly (amic acid) anhydrides. Likewise, for example, olefin addition products of itaconic, citraconic and mesaconic acid are also suitable. In addition, copolymers of unsaturated carboxylic acids, for example maleic, fumaric, acrylic or methacrylic acid, can be used. Polyesters bearing carboxyl groups and based on saturated or aromatic dicarboxylic acids such as adipic acid or phthalic acid can also be used.

For example, aluminum triisopropoxides, aluminum tri-sec-butoxides or complex mixed alcohols and partial chelates such as the commercial products from Condea, Hamburg, Dorox D 15, Dorox D 300, Dorox D 310 are used as Al alcoholates.

Aluminum alcoholates are preferably used, the

All alcoholate groups have bonds on the aluminum. However, it is also possible to use those in which one or two aluminum bonds are occupied by hydroxyl groups.

Component (b) includes hydraulic media such as e.g. conventional mineral oil selective raffinates, hydrocrackates, hydrogenates, poly-alpha-olefins or synthetic esters.

The viscosity position of these liquids is selected according to the requirements for the end product.

1 Examples of component (b) are:

Spindelölraffinat 6/20, DEA, Hamburg Kin. Vis. at 40 ° C: 4.2 mm ² / s

Density at 15 ° C: 840 kg / m ³

Solvent raffinate SN 45, DEA, Hamburg

Kin. Vis. at 40 ° C: 6.5 mm ² / s

5 density at 15 ° C: 842 kg / m ³

Hydrocrackate VHVI-light, DEA, Hamburg Kin. Vis. at 40 ° C: 30.4 mm ² / s density at 15 ° C: 854 kg / m ³

Hitec 162, PAO, Ethyl, St. Louis Kin. Vis. at 40 ° C: 5.0 mm ² / s density at 15 ° C: 800 kg / m ³ ₀ Priolube 3958, Unichema, Gouda

Kin. Vis. at 40 ° C: 10.5 mm ² / s density at 15 ° C: 921 kg / m ³

Component (c) comprises conventional hydraulic additives for ₍ - optimizing the hydraulic product properties such as the

Wear protection, aging stability, friction behavior, tendency to foam, corrosion protection or cold behavior.

Examples of component (c) are:

Additin RC 3212, Rhein-Chemie, Mannheim

2-ethylhexyl-Zn-dithiophosphate Irganox L 107, from Ciba-geigy, Basel

2,6-Di-tert-butyl-phenol Viscoplex 1-300, Röhm, Darmstadt c polymethacrylate, 70% in neutral raffinate.

In a preferred method of producing the EVF, the olefin carboxylic acid half ester is initially introduced in dilute form and mixed with the Al carrier component with the rejection of moisture. After the chemical reaction has ended, the nominal viscosity is adjusted with component (b), and additive is added with component (c) in accordance with the respective requirements. The liquids produced in this way show a strongly increasing viscosity increase with a strengthening of the field in the voltage field from approx. 500 V / mm field strength. The optimum responsiveness is in the range of 3-8 kv / mm field strength with an aluminum content of preferably 0.1 to 0.5%. The initial viscosity of the EVF can range from 15 to 6000 mPa s at 40 ° C.

embodiments

In the exemplary embodiments described below, Example 1 is based on an olefin carboxylic acid which has not been reacted with Al alcoholate. It turned out to be ineffective.

Example 2 is based on a reaction with Li alcoholate. The electro-rheological effect of the product is extremely low and can only be demonstrated in a static test.

Examples 3 to 5 describe reaction products according to the invention. The corresponding electrorheological measurement results are shown in Figures 1-5.

Example 1 (comparison)

100 g of an alkenylsuccinic acid half ester with the following characteristics

Density at 15 ° C Kin. Vis. at 40 ° C viscosity at 100 ° C flash point PM mineral oil content acid number (SZ) hydroxyl number (OHZ) were diluted with 100 g of a naphthenic mineral oil cut. The mix continued

0.1% of a commercial demulsifier and 0.1% of a commercial defoamer added.

The final mix had one

Viscosity of 39 mm ² / s at 40 ° C and an acid number of 72 mgKOH / g In the high-voltage rotary rheometer, this mixture showed no detectable increase in shear stress up to 8 KV / mm field strength with a shear stress of D = 1/100.

Example 2 (comparison)

100 g of the final mixture according to Comparative Example 1 were with exclusion of moisture over a period of

30 min. with intensive stirring with a dispersion of 1 g of lithium sec-butoxide in 5 ml of light oil. The temperature was slowly raised over 60 min. on 80

Brought ° C and at this temperature for a further 90 min. held.

After cooling, the reaction product was diluted with 100 ml of petroleum ether and washed 4 times with 60 ml of H2O.

After filtration and evaporation of the petroleum ether 73 g of a product with a

Obtained viscosity of 160 mm ^ / s at 20 ° C and a lithium content of 0.11%. In the high-voltage rotary rheometer, this mixture showed no detectable increase in shear stress up to 8 KV / mm field strength with a shear stress of D = 1/100.

Example 3 (According to the Invention)

Procedure as in Example 2, but with a solution of

2.5 g of aluminum sec-butoxide reacted in 10 ml of light oil. The end product had one

Viscosity of 330 mm ² / s at 40 ° C and a

Aluminum content of 0.24%. The product showed a strong electroviscous effect, shown on the basis of the results in FIGS. 1 and 2.

Example 4

Procedure as in Example 2, but with a solution of

1.7 aluminum sec-butylate implemented in 8 ml of light oil.

The end product had a viscosity of 826 mm ² / s at 40 ° C. and an aluminum content of 0.17%. The product showed a strong electroviscous effect, shown on the basis of the results in FIG. 3.

Example 5

Procedure as in Example 2, but with a solution of

1, 2 aluminum sec-butoxide in 5 ml of light oil.

The end product had one

Viscosity of 800 mm ² / s at 20 ° C and an aluminum content of 0.1%. The product shows a strong electroviscous effect, shown on the basis of the results in FIGS. 4 and 5.

Claims

1. Homogeneous electroviscous liquids, characterized in that they contain or consist of aluminum soaps which are reacted by reacting one or more saturated and / or unsaturated monomeric, oligomeric and / or polymeric C3 to C32 polycarboxylic acid (s) with one or more carboxyl groups anhydrides and / or monoesters, its or their alcohol component (s) are straight or branched, mono- or polyhydric Cη-C ^ ₂ ~ alcohols and / or oligomers thereof are provided with one or more aluminum alcoholates her¬, its or their alcohol component (s) one or more aliphatic, straight or branched, monohydric or polyhydric C _j to C g _j alcohols.

2. Electroviscous liquids according to claim 1, d a d u r c h g e k e n n z e i c h n e t that the aluminum soaps by reacting one or more

Polycarboxylic acids, anhydrides or half esters with 3 to 18 carbon atoms, in particular with 12 to 18 carbon atoms, are produced.

3. Electroviscous liquids according to claim 1 or 2, characterized in that the aluminum soaps are produced by reacting one or more alkenyl succinic acids and / or their half esters with 5 to 18 carbon atoms, in particular with 12 to 18 carbon atoms.

4. Electroviscous liquids according to any one of the preceding claims, that the reaction products of the polycarbonates, anhydrides or half esters with aluminum alcoholates are used as aluminum soaps, in which all valences of the aluminum or part thereof are converted.

5. Electro-viscous liquids according to one of the preceding claims, that the aluminum soaps are the reaction products of the polycarboxylic acids, their anhydrides and in particular their half esters, which have one or more free OH groups, with aluminum alcoholates.

6. Electroviscous liquids according to one of the preceding claims, characterized in that the alcohol component (s) of the half esters are di- to tetravalent alcohols with 1 to 6 and in particular with 2 to 5 carbon atoms and their oligomers.

7. Electroviscous liquids according to one of the preceding claims, b e s t e h e n d a u s,

(a) 2 to 50% by weight of the aluminum soap, in a homogeneous solution

(b) 50 to 98% by weight of a conventional hydraulic base fluid, and additional

(c) 0 to 10% by weight of soluble, known hydraulic oil additives, in each case based on the total composition.

8. Electroviscous liquids according to one of claims 1 to 6, b e s t e h e n d a u s,

(a) 5 to 40% by weight of the aluminum soap, in a homogeneous solution

(b) 60 to 95% by weight of a conventional hydraulic base fluid, and additional

(c) 0 to 5% by weight of soluble hydraulic oil additives known per se, in each case based on the overall composition.

9. Electroviscous liquids according to one of claims 1 to 6, b e s t e h e n d a u s, (a) 10 to 35% by weight of the aluminum soap, in homogeneous solution with (b) 65 to 90% by weight of a conventional one

Hydraulic base fluid, and additionally (c) 0.1 to 2 wt.% Soluble, known per se

Hydraulic oil additives, each based on the total composition.