Functional fluid composition

Abstract

A functional fluid composition useful as a brake fluid comprising from 0 to 94.99% by weight of alkoxy glycols of borate esters, from 5 to 99.99% by weight of alkoxy glycols, from 0.01 to 5% by weight of alkoxylates of saturated or unsaturated hydroxy-substituted fatty acids such as ricinoleic acid or esters thereof, the hydroxyl group located on the fatty acid side chain being etherified by at least one oxyalkylene unit, and from 0 to 10% by weight of an additive package comprising additives with corrosion inhibition action.

Claims

1. A brake fluid composition, comprising: (A) from 15 to 90% by weight, based on a total weight of the composition, of one or more alkoxy glycol borate esters having formula (I)
[R.sup.1O(CH.sub.2CH.sub.2O).sub.n].sub.3B(I) wherein R.sup.1 is a C.sub.1- to C.sub.8-alkyl radical or a mixture of such radicals and n has a value of from 2 to 6; (B) from 5 to 99.99% by weight, based on the total weight of the composition, of one or more alkoxy glycol components having formula (II)
R.sup.2O(CH.sub.2CH.sub.2O).sub.mH(II) wherein R.sup.2 is a C.sub.1- to C.sub.8-alkyl radical or a mixture of such radicals and m has a value of from 2 to 6, and R.sup.2 is different or identical to R.sup.1 and/or m is different or identical to n; (C) from 0.01 to 5% by weight, based on the total weight of the composition, of an alkoxylate of naturally occurring castor oil, wherein hydroxyl group located on fatty acid side chain of the alkoxylate is etherified by at least one oxyalkylene unit; and (D) from 0 to 10% by weight, based on the total weight of the composition, of an additive package comprising one or more additives with corrosion inhibition action, wherein the brake fluid composition does not comprise a defoamer.

2. The brake fluid composition according to claim 1, wherein component (C) is prepared by reaction of the castor oil with at least one alkylene oxide.

3. The brake fluid composition according to claim 1, wherein component (C) comprises from 2 to 200 ethylene oxide units.

4. The brake fluid composition according to claim 1, wherein component (A) comprises at least one alkoxy glycol borate of the formula (I) and n has a value of from 2 to 4.

5. The brake fluid composition according to claim 1, wherein component (A) comprises at least one alkoxy glycol borate of the formula (I), n has a value of 3, and R.sup.1 is a methyl radical.

6. The brake fluid composition according to claim 1, wherein component (B) comprises a mixture of alkoxy glycols of the formula (II) comprising solely or predominantly species with m=3 and/or 4.

7. The brake fluid composition according to claim 1, comprising component (D), which is at least one alkylamine ethoxylate comprising at least one linear or branched C.sub.3 to C.sub.20 alkyl chain and 1 to 35 ethylene oxide units.

8. The brake fluid composition according to claim 1, exhibiting a dry equilibrium reflux boiling point (ERBP) of at least 260 C. and/or a wet equilibrium reflux boiling point (WERBP) of at least 180 C.

9. The brake fluid composition according to claim 1, exhibiting a low temperature kinematic viscosity of less than 750 centistokes, determined at a temperature of 40 C.

10. A method for actuating a braking mechanism, the method comprising: transferring the brake fluid composition according to claim 1 to the braking mechanism.

11. A method for preparing a brake fluid, the method comprising: introducing an alkoxylate of naturally occurring castor oil, which has hydroxyl group located on fatty acid side chain etherified by at least one oxyalkylene unit, as an additive with lubricating action into the brake fluid.

Description

EXAMPLES

(1) The friction coefficient values of the following function fluid compositions containing a castor oil ethoxylate according to the present invention (FFC1, FFC2 and FFC4) were determined according to the test procedures of DIN 51834-2, using elastomeric material test plates EPDM RM-69. For comparison, the friction coefficient value of a corresponding functional fluid composition without such castor oil ethoxylate (FFC3) was determined and is confronted to FFC1 and FFC2. The lower the friction coefficient value the better the lubricity properties of the functional fluid composition.

Example 1

(2) Measurements at 60 C., weight 300 g, ball diameter of 6 mm, 50 Hz, way length 1000 m Compositions of FFC1, FFC2 and FFC3 (comparative) [% by weight]:

(3) TABLE-US-00001 FFC1 FFC2 FFC3 Methyl triethylene glycol borate ester 61.6 61.6 61.7 Methyl triethylene glycol 26.3 25.7 26.4 n-Butyl triethylene glycol 10.05 9.65 10.05 Castor oil ethoxylate .sup.1) 0.2 0.2 0 Diisopropanolamine 1.0 1.0 1.0 Octylamine ethoxylate (2 EO units) 0.8 0.8 0.8 Tolutriazol 0.05 0.05 0.05 Diethylene glycol 0 1.0 0 Friction coefficient values 0.06 0.06 0.21 .sup.1) Castor oil reacted with 40 moles of ethylene oxide (i.e. on average 13.3 moles of ethylene oxide per mole of ricinoleic acid unit), ethoxylation solely occuring at the hydroxyl group located on the fatty acid side chain and keeping the glycerol triester function

Example 2

(4) Measurements at 100 C., weight 500 g, ball diameter of 1.3 mm, 50 Hz, way length 1000 m Compositions of FFC2, FFC4 and FFC3 (comparative) [% by weight]:

(5) TABLE-US-00002 FFC2 FFC4 FFC3 Methyl triethylene glycol borate ester 61.6 61.55 61.7 Methyl triethylene glycol 26.3 25.7 26.4 n-Butyl triethylene glycol 10.05 9.65 10.05 Castor oil ethoxylate .sup.1) 0.2 0.2 0 Castor oil ethoxylate .sup.2) 0 0.05 0 Diisopropanolamine 1.0 1.0 1.0 Octylamine ethoxylate (2 EO units) 0.8 0.8 0.8 Tolutriazol 0.05 0.05 0.05 Diethylene glycol 0 1.0 0 Friction coefficient (start value t.sub.0) 0.23 0.21 0.25 Time to damage (t.sub.dam) [h:min] 3:05 3:48 2:38 .sup.1) Castor oil reacted with 40 moles of ethylene oxide (i.e. on average 13.3 moles of ethylene oxide per mole of ricinoleic acid unit), ethoxylation solely occuring at the hydroxyl group located on the fatty acid side chain and keeping the glycerol triester function .sup.2) Castor oil reacted with 20 moles of ethylene oxide, ethoxylation solely occuring at the hydroxyl group located on the fatty acid side chain and keeping the glycerol triester function t.sub.0 is the friction coefficient at the beginning of the measurements. Time to damage (t.sub.dam) depicts the time from the beginning of the measurement to damage of the test plate.