US3524816A

US3524816A - Polyether compositions useful as hydraulic fluids

Info

Publication number: US3524816A
Application number: US577185A
Authority: US
Inventors: Hugh J Hagemeyer Jr; Alden E Blood; James D Heller
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1966-09-06
Filing date: 1966-09-06
Publication date: 1970-08-18
Anticipated expiration: 1987-08-18

Description

United States Patent Office 3,524,816 Patented Aug. 18, 1970 3,524,816 POLYETHER COMPOSITIONS USEFUL AS HYDRAULIC FLUIDS Hugh J. Hagemeyer, Jr., Alden E. Blood, and James D. Heller, Longview, Tex., assignors to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Filed Sept. 6, 1966, Ser. No. 577,185 Int. Cl. C09k 3/02 US. Cl. 252-73 4 Claims ABSTRACT OF THE DISCLOSURE A mixture of polyethers having the general formulae l) HOCH CH O(CH CH O CHzCHZOH and 2) C Ha (CH3)zCHOH-CH2O CH2CH20)xH O H Ha wherein x is a whole number of from 1-10, said mixture being useful as components of hydraulic fluids.

DISCLOSURE This application relates to methods and materials for the production of hydraulic fluids and hydraulic fluid components. More particularly, this invention relates to polyether brake fluid components and brake fluids containing such polyether components.

In commercial brake fluids a very delicate balance of properties is required in order that the finished fluids meet the rigid requirements set up by the Society of Automotive Engineers, hereinafter referred to as SAE. Because of this very delicate balance of properties the substitution of components which are ordinarily considered similar in chemical and physical properties for those used in previously known brake fluids often results in fluids which are unsatisfatcory according to SAE standards. Moreover, variation in the amounts of components also frequently results in fluids that are unsatisfactory according to SAE standards.

Acceptable brake fluids are multi-component fluids which contain various ingredients to fulfill the function of a base lubricant, rubber swell inhibitor, viscosity improver, solvent, coupler, and antioxidant. For the most part, brake fluids have conventionally been mixtures of alcohols and glycols in which minor amounts of other addenda are utilized to perform the specific functions such as those of an antioxidant. More recently the use of ethylene oxide adducts of ethylene glycol has been accepted in the trade. Because of the viscosity problems presented by use of the pure adduct, modified reaction products have been frequently utilized. One of the more common modifications is the utilization of some propylene oxide in the adduct. This results in a random mixture which has improved viscosity characteristics. The utilization of such adducts, however, is associated with the normal problems involved with maintaining the delicately restrictive component ratios. Ever increasing demands for improved brake fluids have stimulated continued research efforts directed to meeting such demands.

It is therefore one object of this invention to produce novel polyether brake fluid components. Another object is to produce brake fluid components which allow wider variation in brake fluid component ratios. Another object of this invention will be to provide brake fluids containing novel polyether components. Still another object of this invention is to produce brake fluids in which the specific fluid components can ve varied to a greater degree and yet meet the rigid SAE specifications. Still another object is to provide brake fluid components which perform a dual function, more particularly to perform the function of a hydraulic fluid base lubricant and a rubber swell inhibitor. Still another object is to provide brake fluids having improved volatility characteristics and having excellent viscosity properties.

These and other objects of the invention which will become apparent hereinafter are accomplished by the utilization of an ethylene oxide adduct of ethylene glycol containing a modifying amount of 2,2,4-trimethylpentanediol-l,3. These adducts are generally prepared by reacting the trimethylpentanediol with the ethylene glycol and ethylene oxide, particularly when these materials are present in the reaction mixture in a ratio of from 0.5-2.0 to 3.0-4.5 to 12-24 mole ratio respectively. The reaction is generally catalyzed with an acid or basic catalyst such as Lewis acids, sulfuric acid, benzene sulfonic acid, Raney nickel, sodium hydroxide, boron trifluoride and piperidine. It has been found that trialkyl amines are particularly useful catalysts in that their presence in the resultant product is not detrimental in brake fluids. The reaction is most preferably carried out in an inert environment such as under nitrogen gas and is normally conducted at an elevated temperature of about to 125 C., preferably at -115 C. At that temperature range the reaction is normally complete within a two to five hour period but usually is complete in about 3 /2 hours. The ethylene oxide utilized in the reaction is most advantageously added gradually to the reaction mixture and upon fiinal addition the reaction mixture is allowed to cool slowly and is then filtered.

The filtered product from the reaction scheme outlined above using a trialkylamine catalyst, e.g. triethylamine, has the advantage of being sufliciently pure to obviate any further purification step. The product may be used directly in brake fluids. The product comprises a mixture of compounds having the structural Formulas I and II HOCH CH O CH CH O CH CH OH oHmoH-cH-o orimouzowmcmopn wherein x is a whole number of from 0 to 10, the average value of x being 3 to 4, and wherein the mixture contains at least some polyethers of Formula I and at least some of Formula II. The relative amounts of the polyethers of Formula I as compared to those of Formula II generally range in the area of from 1-1 to 2-1.

The following specific example is indicative of the general method which can be used in the preparation of the above described adducts.

EXAMPLE 1 To a 2-liter, 3-necked flask there was added 1 mole of 2,2,4-trimethylpentanediol-1,3; 4 moles of ethylene glycol; and 40 ml. of triethylamine. The reaction vessel was then fitted with condensers, addition funnels, thermowell, and a stirring rod with watercooled bearing. The reactor was purged with N and the contents heated to 100 C. The addition of 18 moles of liquid ethylene oxide was then started and carried out over a 3 /2 hour period. The reaction becomes exothermic after the addition of ca. 75 ml. of ethylene oxide, and the reaction temperature is controlled at 100-115 C. After final addition, the reaction product is allowed to cool slowly and is then filtered. No stripping or additional processing is required before utilizing the product as a hydraulic fluid base lubricantrubber swell inhibitor.

The adduct mixture prepared from Example I is advantageously utilized in the preparation of brake fluids The composition has the advantage of performing the dual functions of a base lubricant and a partial rubber swell inhibitor. It has been found that such preparation when mixed with other normal brake fluid components allows for wider variation in the ratios of the individual compo- (butyl amines and tert butyl hydroquinone) to produce a homogeneous, clear yellow fluid. This fluid was subjected to evaluation as a hydraulic fluid under SAE 170B specifications for 70R1 heavy duty brake fluids. This fluid met all requirements set forth by the specifications. The

nents. The total brake fluid has properties which fall well major results of this evaluation where as follows:

within the requirements for the two broad commercial TABLE 1 classifications, 70R1 heavy duty and 70R3 extra heavy duty, i.e. classifications which meet the diiferent SAE Fluid i require ents max.

specifications according to those set forth in SAE procedure a NOB-Hydraulic Brake Fluids. With the exception of 5 22 vlscgslty (cclltistOkeSb-e i oint, F 157 145.5

speclalized military hydraulic fillldS, all brake flllldS fall Percent evaporation 212 12).- 73 so into these two commercial classifications. The main dilferlj ihfgg fi fig f ffk g; 8:

once in the speclficatlons for the classifications lies in the I requirements for boiling point and flash point.

The blake fluids according f thls lllvel'ltloll comprise 3 These examples that follow represent formulations se- Sllbstalltlal am011nt 0f the YlP P i/ lected from a wide range of possible compositions of each y y OXlde adduct fliescllbed 111 comblnatloll fluid type. Each example shows variations in some of the Wlth VQIIOIIS alcohols Such as mlXed y and 116x311 a160- fluid components to illustrate the use of the newly develhels, diethylene y l monomethyl ether, heXylene g y oped base lubricant in either 70R1 or 7on3 brake fluids. dlethylene glycol, mlXed p y 316911015, l/ P Each formulation also contains corrosion and oxidation mixed y alcohols; and various Cellosolves, h inhibitors, e.g. the secondary amines and di-tertiarybutyl as ethylene glycol monoethyl ether, ethylene glycol monoh d i previously i d butyl ether, and ethylene glycol monoisebutyl ether and The examples below indicate that when components are esters such as y p i T held within the desired ranges indicated above all SAE concentration of the trimethylpentanediol adduct in the specifications are met.

Example N 0.

Fluid Type 70m 70R1 7on3 70R3 7on3 70R1 70R1 70m 70R1 70R1 Parts Component:

TMPD/Ethylene glyool/ ethylene oxide. 33 Diethylene glycoL 28 2-methylpentnno 11 Alcohol 750 l 12 Ethylene glycol monobutyl ether 16 Mixed amyl alcohols 2 Alcohol 3-58B 3 Finished fiuld properties:

F. viscosity (centistokes) Natural rubber swell (in) Percent evaporation l C4-C mixed primary and secondary alcohols. 1 Approximately 64% n-amyl, 35% Z-Me-butyl, 1% n-butyl. 8 27% 2-methypentanol, 10% isobutanol, 54%Alcohol 750.

various brake fluids generally varies from about 20% by weight to above 39% by weight. For the heavy duty type hydraulic brake fluids it is generally advantageous to utilize the trimethylpentanediol adduct in a concentration of from 21% by weight to about 31% by weight. For the extra heavy duty hydraulic brake fluids of the present invention it is generally advantageous to utilize a percentage range of about 25-30% by weight of the trimethylpentanediol adduct but higher concentrations can be utilized such as 28-39% by weight with the total composition still being capable of meeting the rigid SAE requirements. The brake fluids also contain a minor amount of antioxidant. While generally accepted antioxidants can be utilized in the brake fluid components of the instant invention it has been found that minor amounts, of up to 2%, of a 2-1 mixture of di-n-butylamine and 2,5-di-tert-butylhydroquinone together with tri-n-butylamine forms an especially useful antioxidant for the brake fluids of the instant invention.

The following examples illustrate various brake fluids of the instant invention but are not intended to be limitations thereof.

EXAMPLE 2 There was mixed 27 parts of the TMPD/ethylene glycol/ ethylene oxide adduct as described above, 35 parts diethylene glycol, 8 parts by weight 2-methylpentanol, 15 parts by weight ethylene glycol monobutyl ether plus minor amounts of corrosion and oxidation inhibitors Particularly valuable brake fluids according to this invention have the following compositions.

(A) Heavy duty hydraulic brake fluids (70Rl type):

25-35% by weight the polyether adduct mixture; 27-37% by Weight diethylene glycol; 8-16% by weight Z-methylpentanol; 8-16% by weight C -C primary and secondary alcohols; 8-l6% ethylene glycol monobutyl ether; 0.ll.0% antioxidant.

21-31% by weight the polyether adduct mixture;

21-31% Alcohol 3-58B, an alcohol mixture of about 27% 2-methylpentanol, 19% isobutanol, and 54% of various other C -C mixed primary and secondary al cohols (Alcohol 750);

7-18% by weight ethylene glycol monobutyl ether; 31-41% by weight diethylene glycol; 0.1-l.0% by weight antioxidant.

(B) Extra heavy duty hydraulic brake fluid (70R3 yp 28-39% by weight the polyether adduct mixture; 31-41% by weight diethylene glycol;

20-40% by weight ethylene glycol monobutyl ether; 01-10% by weight antioxidant.

The invention has been described in considerable detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected Within the spirit and scope of the invention as described hereinabove, and as defined in the appended claims.

We claim:

1. A hydraulic fluid consisting essentially of (A) about 25-35% by weight of a mixture of polyethers having the general formulae 1 HOCH CH O CH CH O CH CH OH and (OHahCHCH--OHzO (CHgOHzO) Izli 1) HOCH CH O (CH CH O CH CH OH and (CH3)2CHCH( -CH2O (C HzCHzO );H

O H Ha wherein x is a whole number of from 1-10, the molar ratio of 1) to (2) being in the range of about 1/1 to 2/1,

(E) about 31-41% by weight diethylene glycol,

(C) about 20-40% by weight ethylene glycol monobutyl ether, and

(D) about 0.1-1.0% by weight antioxidant for inhibiting the oxidative degradation of the hydraulic fluid.

3. A hydraulic fluid consisting essentially of (A) about 21-31% by weight of a mixture of polyethers having the general formulae 6 (1) HOCH CH O(CH CH O) CH CH OH and (CHs)zCHCH-( J-OH2O(CHzCHzO),H

OH CH3 wherein x is a whole number of from 1-10, the molar ratio of (1) to (2) being in the range of about 1/1 to 2/1,

(E) about 31-41% by weight diethylene glycol,

(C) about 8-18% by weight ethylene glycol monobutyl ether,

(D) about 5-25% by weight of C primary and secondary alcohols,

(E) about 5-25 by weight of mixed amyl alcohols,

and

(F) about 01-10% by weight antioxidant for inhibiting the oxidative degradation of the hydrulic fluid.

4. A hydraulic fluid consisting essentially of (A) about 21-31% by weight of a mixture of polyethers having the general formulae wherein x is a whole number of from 1-10, the molar ratio of (1) to (2) being in the range of about 1/1 to 2/1, (B) about 21-31% by weight of an alcohol mixture consisting essentially of (1) about 27 wt. percent Z-methylpentanol (2) about 19 wt. percent isobutanol, and (3) about 54 wt. percent of C -C primary and secondary alcohols, (C) about 31-41% by weight diethylene glycol, (D) about 7-18% by weight ethylene glycol monobutyl ether, and (E) about 0.1-1.0% by Weight antioxidant for inhibiting the oxidative degradation of the hydraulic fluid.

References Cited UNITED STATES PATENTS 2,425,755 8/ 1947 Roberts et a]. 3,062,747 11/1962 Fife et a1. 25273 3,324,035 6/1967 Nankee et a1. 252-73 3,341,456 9/1967 Sawyer 252-75 3,346,501 10/1967 Boehmer 252-73 LEON D. ROSDOL, Primary Examiner D. SILVERSTEIN, Assistant Examiner US. Cl. X.R. 252--77