Low Viscosity Functional Fluid Composition

Abstract

This invention relates to a functional fluid, comprising: (A) from 50 to 85 wt.-% of alkoxy glycol according to formula (I): CH.sub.3—O—(CH.sub.2—CH.sub.2—O).sub.n—H, wherein n is a number from 2 to 5, with the proviso that in at least 30 wt.-% of all compounds according to formula (I), n is 3, and (B) from 1 to 20 wt.-% of alkoxy glycol according to formula (II): R.sub.1—O—(CH.sub.2—CH.sub.2—O).sub.m—H, wherein R.sub.1 is a C2 to C8 alkyl residue, m is a number from 2 to 6, with the proviso that in at least 65 wt.-% of all compounds according to formula (II), m is 3, and (C) from 6 to 35 wt.-% of at least one compound according to formula (III): H—O—(CH.sub.2—CH.sub.2—O).sub.k—H, wherein k is a number of 2 or higher, with the proviso that in at least 80 wt.-% of all compounds according to formula (III), k is 2 or 3, (D) at least one additive.

Claims

1.-26. (canceled)

27. A functional fluid, comprising (A) from 50 to 85 wt.-% of alkoxy glycol according to formula (I)
CH.sub.3—O—(CH.sub.2—CH.sub.2—O).sub.n—H  (I)  wherein n is a number from 2 to 5, with the proviso that in at least 30 wt.-% of all compounds according to formula (I), n is 3, and (B) from 1 to 15 wt.-% of alkoxy glycol according to formula (II)
R.sub.1—O—(CH.sub.2—CH.sub.2—O).sub.m—H  (II)  wherein  R.sub.1 is a C.sub.2 to C.sub.8 alkyl residue,  m is a number from 2 to 6,  with the proviso that in at least 65 wt.-% of all compounds according to formula (II), m is 3, and (C) from 6 to 35 wt.-% of at least one compound according to formula (III)
H—O—(CH.sub.2—CH.sub.2—O).sub.k—H  (III)  wherein k is a number of 2 or higher, with the proviso that in at least 80 wt.-% of all compounds according to formula (III), k is 2 or 3, (D) at least one additive, selected from the group consisting of corrosion inhibitor, amines, stabilizers, defoamers and lubricants, wherein the fluid comprises at most 3 wt.-% of an ester of boric acid and a glycol or alkyl polyglycol compound.

28. The functional fluid according to claim 27, wherein the components (A) to (D) add up to 100 wt.-%.

29. The functional fluid according to claim 27, wherein 50-90 wt.-% of all compounds according to formula (I) have n=3.

30. The functional fluid according to claim 27, wherein 10 to 50 wt.-% of all compounds according to formula (I) have n=4 or 5.

31. The functional fluid according to claim 27, wherein 2.5 wt.-% or less of all compounds according to formula (I) have n=2.

32. The functional fluid according to claim 27, wherein the content of component (A) in compounds according to formula (I) wherein n=1 is 1 wt.-% or less.

33. The functional fluid according to claim 27, wherein the content of component (A) in compounds according to formula (I) wherein n=6 or higher is 3 wt.-% or less.

34. The functional fluid according to claim 27, wherein the total content of the fluid in boric acid esters is at most 0.3 wt.-%.

35. The functional fluid according to claim 27, wherein 10 wt.-% or more of all compounds according to formula (II) have m=4.

36. The functional fluid according to claim 27, wherein R.sub.1 is C.sub.2 to C.sub.4 alkyl, preferably ethyl or butyl.

37. The functional fluid according to claim 27, wherein in at least 75 wt.-% of all compounds according to formula (II) m=3.

38. The functional fluid according to claim 27, wherein 3 wt.-% or less of all compounds according to formula (II) have m=2.

39. The functional fluid according to claim 27, wherein 5 wt.-% or less of all compounds according to formula (II) have m=5 or higher.

40. The functional fluid according to claim 27, wherein the total amount of compounds according to formula (III), wherein k=2 is 1 to 15 wt.-% of the total fluid.

41. The functional fluid according to claim 27, wherein the total amount of compounds according to formula (III) wherein k=3 is 5 to 15 wt.-% of the total fluid.

42. The functional fluid according to claim 27, wherein the total amount of compounds according to formula (III) with k=4 or higher is 7 wt.-% or less of the total fluid.

43. The functional fluid according to claim 27, wherein the weight ratio between component (A) and component (B) is (A):(B)=82:1 to 6:1.

44. The functional fluid according to claim 27, wherein the weight ratio between compounds according to formula (I) with n=3 and n=4 or higher is (n=3):(n=4, or higher) is 1:1 to 6:1.

45. The functional fluid according to claim 27, wherein the weight ratio between component (A) and component (C) is (A):(C)=2.0:1 to 8.2:1.

46. The functional fluid according to claim 27, wherein component (D) is present in an amount of 0.4 to 6 wt.-%, and wherein the corrosion inhibitor is selected from the group consisting of C.sub.8 to C.sub.22 fatty acids, esters of phosphorus or phosphoric acid with C.sub.1 to C.sub.18 aliphatic alcohols, phosphites having at least one C.sub.1 to C.sub.12 hydrocarbon residue; heterocyclic organic compounds having at least one nitrogen atom as heteroatom, and mixtures thereof; the stabilizer is selected from the group consisting of substituted phenols, sterically hindered amines and mixtures thereof; the defoamer is selected from the group consisting of natural oils, glycerides, waxes, powdered silica, ethylene oxide/propylene oxide block copolymers, silicone based defoamers and mixtures thereof; the lubricant is selected from the group consisting of polypropylene oxides, random poly (C.sub.2- to C.sub.4-alkylene) oxides, random mono C.sub.1 to C.sub.4 substituted poly (C.sub.2- to C.sub.4-alkylene) oxides, castor oil, ricinoleic acid, ethoxylates of castor oil or ricinoleic acid, and mixtures thereof.

47. The functional fluid according to claim 27, wherein the amine is selected from the group consisting of alkyl amines, cycloalkyl amines, alkanol amines, alkyl amine ethoxylates and mixtures thereof.

48. The functional fluid according to claim 27, comprising 0.3 to 2 wt.-% of an amine within the component (D), weight-% being relative to the fluid weight.

49. The functional fluid according to claim 27, wherein the fluid's content in esters of boric acid and glycol or alkyl polyglycol compounds is less than 3 wt.-%.

50. The functional fluid according to claim 27, the fluid having a kinematic viscosity of less than 800 centistokes at −40° C., a dry equilibrium reflux boiling point of at least 250° C. and a wet equilibrium reflux boiling point of at least 160° C.

51. A brake fluid comprising (A) from 50 to 85 wt.-% of alkoxy glycol according to formula (I)
CH.sub.3—O—(CH.sub.2—CH.sub.2—O).sub.n—H  (I)  wherein n is a number from 2 to 5, with the proviso that in at least 30 wt.-% of all compounds according to formula (I), n is 3, and (B) from 1 to 15 wt.-% of alkoxy glycol according to formula (II)
R.sub.1—O—(CH.sub.2—CH.sub.2—O).sub.m—  (II)  wherein  R.sub.1 is a C.sub.2 to C.sub.8 alkyl residue,  m is a number from 2 to 6,  with the proviso that in at least 65 wt.-% of all compounds according to formula (II), m is 3, and (C) from 6 to 35 wt.-% of at least one compound according to formula (III)
H—O—(CH.sub.2—CH.sub.2—O).sub.k—H  (III)  wherein k is a number of 2 or higher, with the proviso that in at least 80 wt.-% of all compounds according to formula (III), k is 2 or 3, (D) at least one additive, selected from the group consisting of corrosion inhibitor, amines, stabilizers, defoamers and lubricants, wherein the fluid comprises at most 3 wt.-% of an ester of boric acid and a glycol or alkyl polyglycol compound.

52. A method of operating a vehicular brake, the method comprising the step of transmitting hydraulic pressure by a fluid comprising (A) from 50 to 85 wt.-% of alkoxy glycol according to formula (I)
CH.sub.3—O—(CH.sub.2—CH.sub.2—O).sub.n—H  (I)  wherein n is a number from 2 to 5, with the proviso that in at least 30 wt.-% of all compounds according to formula (I), n is 3, and (B) from 1 to 15 wt.-% of alkoxy glycol according to formula (II)
R.sub.1—O—(CH.sub.2—CH.sub.2—O).sub.m—H  (II)  wherein  R.sub.1 is a C.sub.2 to C.sub.8 alkyl residue,  m is a number from 2 to 6,  with the proviso that in at least 65 wt.-% of all compounds according to formula (II), m is 3, and (C) from 6 to 35 wt.-% of at least one compound according to formula (III)
H—O—(CH.sub.2—CH.sub.2—O).sub.k—H  (III)  wherein k is a number of 2 or higher, with the proviso that in at least 80 wt.-% of all compounds according to formula (III), k is 2 or 3, (D) at least one additive, selected from the group consisting of corrosion inhibitor, amines, stabilizers, defoamers and lubricants, wherein the fluid comprises at most 3 wt.-% of an ester of boric acid and a glycol or alkyl polyglycol compound.

Description

EXAMPLES

[0092] Table 1 shows functional fluid compositions and their performance. Numbers are provided in wt.-%, unless noted otherwise.

TABLE-US-00002 TABLE 1 Example 1 (.diamond-solid.) Example 2 (.diamond-solid.) Example 3 (.diamond-solid.) Example 4 (.diamond-solid.) Component A 71.598 70.238 72.813 74.15 n = 2 0 0.5 n = 3 51.698 50.238 37.813 63.65 4 and 5 (>60% n = 4) 19.9 20 35 10 Component B (R.sub.1 = n-butyl) 9 9 9.9 2 m = 3 7.2 7.2 7.92 1.6 m = 4 and higher (>80% m = 4) 1.8 1.8 1.98 0.4 Component C 18 16.5 16 23 k = 2 (DEG) 9.5 8 8.5 9.5 k = 3 (TEG) 8.5 8.5 7.5 10 k = 4 and higher 3.5 Component D 1.4015 4.2615 1.2865 0.8513 Lubricant ethylene/propylene oxide random 3 copolymer mono butyl ether Castor Oil ethoxylate (50 wt-% EO) 0.1 Amine Diisopropanol amine 1.04 0.935 0.5 Octylamine + 2EO 1 Rest Defoamer (polyether modified siloxane) 0.001 0.001 0.001 0.001 BHT 0.2 0.2 styrenated diphenylamine 0.2 0.2 Oleic acid 0.1 0.1 Phosphoric acid ester 0.06 0.06 0.05 0.05 dye stuff 0.0005 0.0005 0.0005 0.0003 Total 100.000 100.000 100.000 100.00 WERBP [° C.] 166 (.diamond-solid.) 161 (.diamond-solid.) 162 (.diamond-solid.) 165 (.diamond-solid.) ERBP [° C.] 258 (.diamond-solid.) 261 (.diamond-solid.) 263 (.diamond-solid.) 264 (.diamond-solid.) viscosity (−40° C.) [mm.sup.2/s] 701 (.diamond-solid.) 709 (.diamond-solid.) 742 (.diamond-solid.) 733 (.diamond-solid.) Component ratios Component A:B 7.96 7.8 7.35 37.08 Component A n = 3/n = 4 or higher 2.60 2.51 1.08 6.37 Component A:C 3.98 4.26 4.55 3.22 Comparative Comparative Comparative example 1 (.square-solid.) example 2 (.square-solid.) example 3 (.square-solid.) Component A 64.788 60.938 65.6385 N = 2 n = 3 9 (.square-solid.) 25.15 45.6385 4 and 5 (>60% n = 4) 55.788 35.788 20 Component B (R.sub.1 = n-butyl) 19.15 20 (.square-solid.) 9 m = 3 15.32 16 7.2 m = 4 and higher (>80% m = 4) 3.83 4 1.8 Component C 15 18 16.5 k = 2 (DEG) 8 9.5 8 k = 3 (TEG) 7 8.5 4 k = 4 and higher 4.5 (.square-solid.) Component D 1.0615 1.0615 8.8615 Lubricant ethylene/propylene oxide random 8 copolymer mono butyl ether Castor Oil ethoxylate (50 wt-% EO) Amine Diisopropanol amine 0.5 0.5 0.5 Octylamine + 2EO Rest Defoamer (polyether modified siloxane) 0.001 0.001 0.001 BHT 0.2 0.2 styrenated diphenylamine 0.2 0.2 0.2 Oleic acid 0.1 0.1 0.1 Phosphoric acid ester 0.06 0.06 0.06 dye stuff 0.0005 0.0005 0.0005 Total 100.000 100.000 100.000 WERBP [° C.] 158 (.square-solid.) 157 (.square-solid.) 159 (.square-solid.) ERBP [° C.] 274 (.diamond-solid.) 267 (.diamond-solid.) 262 (.diamond-solid.) viscosity (−40° C.) [mm.sup.2/s] 920 (.square-solid.) 803 (.square-solid.) 968 (.square-solid.) Component ratios Component A:B 3.38 3.05 7.29 Component A n = 3/n = 4 or higher 0.16 0.70 2.28 Component A:C 4.32 3.39 3.98 (.diamond-solid.) = according to the present invention, or according to the required specification (.square-solid.) = not according to the invention, or not according to the required specification