DE1031921B - Brake fluids - Google Patents

Description

GERMAN

The subject of patent 850 053 is the composition of brake fluids from 10 to 25 percent by volume Mono- and diricinoleates of aliphatic glycols, 3 to 15 percent by volume of aliphatic glycols, 10 to 24 percent by volume 2-methyl-2,4-pentanediol and 45 to 70 percent by volume of lower monohydric alcohols or lower monoalkyl ethers of mono- or diethylene or -propylene glycol.

In contrast, the invention is characterized by a further content of essentially water-insoluble Polypropylene glycol with an average molecular weight of 1000 to 3000, preferably about 2000.

The content of this polypropylene glycol is preferably 5 to 20 parts by volume of the total liquid.

The following requirements are made of a satisfactory brake fluid:

The brake fluid must have a boiling point so high that it does not evaporate during use. It must not freeze or solidify even in very low winter temperatures. At the deepest surrounding Temperature, the viscosity of the brake fluid must not exceed approx. 2200 cP. The brake fluid is allowed Do not attack metal and do not swell or destroy the rubber seals. Good lubricity, Water compatibility, thermal stability and miscibility with other brake fluids required.

These requirements and also the requirement that the lubricant component is insoluble in water become according to the invention fulfilled in that the lubricant component in the brake fluid according to the invention consists partly of glycol ricinoleate and partly of polypropylene glycol.

The brake fluid according to the invention contains a mixture as a water-insoluble lubricant component from a ricinoleate of an aliphatic glycol and a water-insoluble polypropylene glycol with a average molecular weight from 1000 to 3000. This liquid contains a diluent as a diluent from the group of propyl alcohols, butyl alcohols, amyl alcohols, methoxybutanol and the lower monoalkyl ethers of ethylene glycol and diethylene glycol. In addition, a relatively small one Amount of one or more glycols, such as propylene glycol, butylene glycol or hexylene glycol, and a Anti-corrosion agent and an anti-oxidation agent.

The mass consists of 10 to 25 percent by volume of a ricinoleate of a glycol, which is an aliphatic glycol with no more than five carbon atoms per molecule, from 3 to 15 percent by volume of a water-insoluble one Polypropylene glycol with an average molecular weight of 1000 to 3000, also from 45 to 70 percent by volume of at least one diluent from the group of propyl alcohols, butyl alcohols, Amyl alcohols, methoxybutanol and the lower mono brake fluids

Addition to patent 850 053

Applicant:

Wagner Electric Corporation,
St. Louis, Mo. (V. St. A.)

Representative: Dr.-Ing. H. Ruschke,

Berlin-Friedenau, Lauterstr. 37,

and Dipl.-Ing. K. Grentzenberg, Munich 27,

Patent attorneys

Claimed priority:
V. St. v. America 9 August 1962

George L. Doelling and Chester B. Swander,

St. Louis, Mo., (V. St. A.),
have been named as inventors

alkyl ethers of ethylene and diethylene glycol, furthermore from 10 to 24 percent by volume of at least one glycol from the group consisting of propylene glycol, butylene glycol and hexylene glycol, if desired together with an anti-corrosion agent and an anti-oxidation agent.
In the lubricant component of the liquid, the ricinoleates of the lower aliphatic glycols and diglycols are preferred because these are very stable, give the liquid good lubricating properties and do not cause the liquid to freeze out at low temperatures, as is the case with castor oil.

Propylene glycol monoricinoleate is the preferred ricinoleate ester of this composition. Diethylene glycol ricinoleate and butylene glycol ricinoleate can also be used. A substantially water-insoluble polypropylene glycol having an average molecular weight of 1,000 to 3,000 can also be used in the lubricant component of the liquid. The preferred polypropylene glycol having an average molecular weight of about 2000. This product has as the E and about 20 ⁰ 37.8 ⁰ C to about 40 ⁰ E is a viscosity which is somewhat lower than the castor oil, for castor oil. Just like castor oil, the swelling effect on rubber is very low.

The diluent or viscosity reducing agent of the preferred liquid can be

80S 530/385

Alcohol, ζ. B. normal butanol or isobutanol.

Glycol ethers, e.g. B. 3-methoxybutanol or diethylene example δ

glycol monoethyl ether or another lower alkyl diethylene glycol monoethyl ether ... 70.0 percent by volume ether of ethylene glycol or diethylene glycol. For polypropylene glycol

Use of diethylene glycol monoethyl ether as 5 (molecular weight 2000) 11.5 "

Diluent should be the pure quality of low propylene glycol 5.0 "

specific weight, as the commercial propylene glycol monoricinoleate 12.5 "

common product up to 20% or more ethylene glycol diphenylpropane 0.3 "

may contain, so for use in this mixture potassium ricinoleate 0.7 "

is not suitable. ok

To prevent corrosion of the metal parts of the _{die obtained by mixing} these components

Brake system is used as an anti-corrosion agent. Brake fluid has the following properties: Potassium ricinoleate, borax, sodium nitrite or diamyl

amine phosphate can be used. The specific weight at 2O ⁰ C can also be 0.993

an antioxidant such as diphenylolpropane or 15 acid number 0.17

Hydroquinone or 2,6-di-tertiary-butyl-4-methylphenol viscosity at - 40 ⁰ C 89.5 ⁰ E

can be added. For the purpose of an additional sufficient viscosity at 18.9 ⁰ C 2.12 ⁰ E

from 0.2 to 3.0% of the corrosion protection agent and 0.1 boiling point, SAE 194 ⁰ C

to 0.3% of Oxydationsschutzmittels, calculated on cold test (6 hours at -51 ⁰ C) liquid

the weight of the liquid. 20th

The proportions of the used in the mixture. The SAE corrosion test, 5 days at 100 ° C, resulted

The particular components are decisive, and the results obtained with this liquid are very satisfactory. The proportions required are selected because the weight loss of tin, steel, aluminum, cast iron, brass and copper required many industrial uses was less than 0.1 mg / cm ² , brake fluid can only be met if it is 25, ie much less than the SAE standards allow. Quantities are used. The rubber swelling started after 5 days at 70 ° C

The following examples are illustrative of a 31 mm Manhattan cup was 4.95 volumes Invention. The examples showing the different percentages.

Explaining proportions and quantities result in about 100 ecm Example 3

Liquid. 3 °

Diethylene glycol monoethyl ether .. 60.00 percent by volume Example 1 Polypropylene glycol

Diethylene glycol monoethyl ether ... 65 percent by volume (molecular weight 2000) 7.5

Polypropylene glycol propylene glycol 4.2

(Molecular weight 2000) 11.5 "35 2-methyl-2,4-pentanediol 10.0

2-methyl-2,4-pentanediol propylene glycol monoricinoleate 17.0 "

(Hexylene glycol) 5.0 "diphenylpropane 0.3

Propylene glycol 5.0

Propylene glycol nonoricin oleate 12.5

Diphenylpropane 0.3

Potassium ricinoleate 0.7

Potassium ricinoleate 1.0 "

40 The brake fluid obtained by mixing these components had the following properties:

Specific gravity at 20 ⁰ C 0.984

The brake fluid acid number mixed from these components is 0.16

ness had the following properties: viscosity at 20 ⁰ C 2.3 ⁰ E

,. Rubber threshold, 5 days at 70 ⁰ C,

Specific weight at 20 C 0.9905 Increase in percentage by volume 4.7%

Color, Parlin scale 3 boiling point; 192 ° C

PH value, electromechanical 8.82 cold test (6 hours at - 51 ° C) liquid

Acid number 0.14 ^v ' ⁵

Viscosity at 37.8 ⁰ C 1.7 ° E 50 _ ....., _CA ~ _T. , _e ~,. _innon

y ν 'ft b' -4O ⁰ C 106 ⁰ E The ubhche SAE corrosion test, 5 days at 100 C,

Flash point '.'. '.'. '.'. '.'. '.'. '.'. '.'. '.'. '.'. '.'. '.'. 101.7 ° C ^er g ^{from the following losses in m} S / ^cm2:

Boiling point: 196.1 ° C. Tinned iron 0.04

Rubber threshold, at 70 ° C steel 0.17

Weight gain after 16 hours 4.23% 55 aluminum - 0.02

Freezing point (6 hours at -51 ⁰ C) ... liquid cast iron 0.13

Brass 0.12

The corrosion test according to the SAE regulations copper 0.02

for hydraulic brake fluids (Standard of Auto- All these values were well below the limit values

motive engineers, standards of automotive engineers) 60 of the regulation.

was at 100 ° C for 5 days with this liquid Example 4

carried out. The aluminum strip showed none

Weight loss. Tin-plated iron, steel, cast iron and 3-methoxybutanol-3 55.0 percent by volume

Copper lost about 0.02 mg / cm ² each. The brass polypropylene glycol

Stripe loss was 0.06 mg / cm ² . All of these results 65 (molecular weight 2000) 10.0 "

were far below the train regulations propylene glycol 6.7 "

allowable loss, 0.5 for brass and copper, 10.0 for 2-methyl-2,4-pentanediol

Tin, steel and cast iron 0.7 and for aluminum propylene glycol monoricinoleate 17.0 "

0.2 mg / cm ² . After the corrosion of the _pH value was 0.3 diphenylolpropane "

equal to 7.6. 70 potassium ricinoleate 1.0 "

The brake fluid obtained by mixing these components has the following properties:

Specific gravity at 20 ° C 0.951

Boiling point 160 ^° C

Viscosity at 20 ⁰ C ° 2.75 E

Cold test (6 hours at -51 ⁰ C) liquid

Rubber swelling, 5 days at 70 ⁰ C,

Increase in volume percentage 4.5%

Example 5

A so-called "arctic" liquid was made by mixing the following ingredients in the following amounts obtain:

Normal butanol 50.0 percent by volume

Diethylene glycol monoethyl ether ... 24.7 "

Polypropylene glycol

(Molecular weight 2000) 7.3

Propylene glycol 6.1 "

2-methyl-2,4-pentanediol 3.0

Propylene glycol monoricinoleate 8.0 "

2,6-di-tert-butyl-4-methylphenol 0.1 "

Potassium ricinoleate 0.5 ,,

The mixed from these components "Arctic" brake fluid had a boiling point of 130 mm ⁰ C. The rubber swelling, 5 days at 70 ° C, on a 31-mm-Manhatten normal cups showed an increase in base diameter of 0.94. In a cold test (6 days at -53 ° C) the liquid was essentially clear and fairly runny. The flash point (Cleveland) was 60 ⁰ C. The specific gravity at 20 ⁰ C was 0.9031, and the _pH value, measured according to the SAE requirement, was 9.1. After adding 5% water and allowing it to stand for 24 hours at -53 ° C, the mixture was still liquid. This brake fluid works even at very low temperatures. After 6 hours it was still liquid at -67.8 ° C.

Example 6

Normal butanol 50.0 percent by volume

Polypropylene glycol

(1200 molecular weight) 19.0

Propylene glycol 9.0 "

1-methyl-2,4-pentanediol 15.0

Diethylene glycol monoricinoleate .... 6.0 ,,

Hydroquinone 0.125 "

Diamylamine 0.75 "

Phosphoric acid (85%) 0.125

The brake fluid obtained by mixing these components had the following properties:

Specific weight at 20 ° C .... 0.899

Boiling point 129 ° C

Flash point (Cleveland) 57 ° C

Gum swelling, 16 hours at 7O ⁰ C, Manhattan-31 mm cup,

Increase in percent by weight ... 2.82% / ₀

p _H value, SAE method 8.3

Cold trial (3 days at -40 ⁰ C) .. liquid, but was

the viscosity is fairly high

Example 7

Isobutanol 60.0 percent by volume

Polypropylene glycol

(Molecular weight 2725) 11.5

2-methyl-2,4-pentanediol 10.0

Propylene glycol monoricinoleate. ... 12.5 ,,

Diphenylpropane 0.3 "

Potassium ricinoleate 0.7 "

The brake fluid obtained by mixing these components had the following properties:

Specific weight at 20 ° C 0.876

Color, Parlin Scale 2

Flash point (Cleveland) 46 ⁰ C

Boiling point 114 ° C

Acid number 0.09

p _H value, SAE method 8.98

Viscosity, SSU at 20 ⁰ C 100

Cold test (3 days at - 40 ⁰ C) pretty

fluid

Rubber swelling (5 days at 70 ⁰ C), increase in diameter of a 31 mm cup 0,94mm

Example 8

Ethylene glycol mono-N-butyl ether .. 45 percent by volume

Normal propanol 15 "

1,3-butylene glycol 6.3

Polypropylene glycol

(Molecular weight 1025) 17.5

!, S-butylene glycol monoricinoleate ... 15.0 "

Potassium ricinoleate 1.1 ,,

2,6-di-tert-butyl-4-methylphenol 0.1 "

The brake fluid obtained by mixing these components had the following properties:

Specific gravity at 2O ⁰ C 0.9287

Flash point (Cleveland) 57 ° C

Boiling point, SAE process 123 ° C

Pn value, SAE method 7.92

Cold test (16 hours at -45.6 ° C) quite

fluid

Claims (2)

Patent claims: 1. Brake fluids according to patent 850 053, characterized by a further content of im substantially water-insoluble polypropylene glycol with an average molecular weight of 1000 to 3000, preferably 2000. 2. Brake fluids according to claim 1, characterized by a content of 5 to 20 parts by volume the total liquid of the water-insoluble polypropylene glycol. Documents considered: French Patent No. 976 467. © £ 09 530/385 6.