US3677948A

US3677948A - Triaryl phosphate functional fluids

Info

Publication number: US3677948A
Application number: US64655A
Authority: US
Inventors: Silvio L Giolito; Stanley B Mirviss
Original assignee: Stauffer Chemical Co
Current assignee: Akzo America Inc
Priority date: 1970-08-17
Filing date: 1970-08-17
Publication date: 1972-07-18
Anticipated expiration: 1989-07-18
Also published as: CA959823A; FR2102295B1; BE771345A; NL7110939A; DE2140465A1; GB1323258A; FR2102295A1

Abstract

THE PRESENT INVENTION RELATES TO A PROCESS AND COMPOSITION FOR TRANSMISSION OF PRESSURE IN A HYDRAULIC SYSTEM COMPRISING A MIXTURE OF A STYRENATED TRIARYL PHOSPHATE AND AN ALKYLPHENYL PHENYL PHOSPHATE.

Description

United States Patent Int. Cl. C09k 3/00 US. Cl. 252-78 7 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to a process and composition for transmission of pressure in a hydraulic system comprising a mixture of a styrenated triaryl phosphate and an alkylphenyl phenyl phosphate.

BACKGROUND OF THE DISCLOSURE Functional fluids suitablefor the operation of hydraulic mechanisms require a combination of properties which are often unattainable in many presently available materials. The properties which are required for safe and satisfactory low temperature operation include a low pour point which permits a hydraulic fluid to operate at low temperatures. Functional fluids should also exhibit low oxidative susceptibility, thereby operating without the buildup of sludge. Another important property of such fluids is a fiat viscosity temperature curve, that is, a high viscosity index which allows the fluid to remain operable over a wide rangeof temperatures. One of the vital properties which is required for fluids which are to be utilized in either the commercial and mining industries or in military use is minimum flammability. Still other desirable qualities for such products include a relatively high boiling point and low corrosive characteristics.

Mixtures of various phosphates have been employed as functional fluids in the past. Triaryl and trialkyl phosphates have been utilized by themselves or in combination with each other to yield functional fluids having a evariety of properties. However, the fluids of the prior art are deficient in one or more of the above properties.

It is an object of the present invention to provide functional fluids which exhibit all the desirable characteristics described above. I

It is a further object of the present invention to provide a totally synthetic based functional fluid comprised of two components which, when combined in varying proportions, give a series of fluids with varying viscosities depending on the proportions; each having superior characteristics to known fluids of similar viscosities.

It has now been discovered that these objects can be accomplished by employing a functional fluid composition comprised of a styrenated triaryl phosphate and an alkylphenyl phosphate.

TECHNICAL DISCLOSURE THE INVENTION These fluids can also contain minor amounts of various additives such as antioxidants, rust inhibitors, defoamers, and load bearing additives.

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The styrenated triaryl phosphates employed in the present invention have a generic formula corresponding to:

(R1). H (B2)! '1 o alli. 0 4! Q o l o 5 6113/ I1 JX 3 wherein x is a number from about 0.5 to about 2, and preferably from about 0.7 to about 1.5 inclusive, n is a number from 1 to 3 inclusive, a and c are each numbers from 0 to 5 inclusive, b is a number from 0 to 4 inclusive, and R R and R are each an alkyl group having from 1 to about 8 carbon atoms. The compounds are characterized by high viscosities, that is, viscosities in excess of 900 Saybolt Universal Seconds at F. The value of x is equal to the average number of styrylphenyl groups per phosphate group. Thus, it designates a mixture of phosphates rather than a pure compound. For example, if the styrenated triaryl phosphate employed is a styrylphenyl phosphate having an x value of 1.5, and an n value of 1, it will be comprised of a mixture of. styrylphenyl diphenyl phosphate, distyrylphenyl phenyl phosphate, triphenyl phosphate and various other isomers; the mixture having an average value of 1.5 styrylphenyl groups per phosphate group. Illustrative of the styrylphenyl compounds which are preferred in the present invention are:

styrylphenyl diphenyl phosphate styrylphenyl dicresyl phosphate styrylphenyl dixylyl phosphate styrylphenyl bis(isopropylphenyl) phosphate styrylphenyl bis(butylphenyl) phosphate isopropylbenzyl phenyl diphenyl phosphate and mixtures of the above With:

bis(styrylphenyl) phenyl phosphate bis(styrylphenyl) cresyl phosphate bis(styrylphenyl) xylyl phosphate and the like.

styrylphenyl diphenyl phosphate and styrylphenyl bis (isopropylphenyl) phosphate having an x value of 0.7 to 1.5 and an n value of l are particularly preferred. Also included in the compounds of the present invention are:

distyrylphenyl diphenyl phosphate distyrylphenyl bis (isopropylphenyl) phosphate tristyrylphenyl diphenyl phosphate bis(distyrylphenyl) phenyl phosphate distyrylphenyl dicresyl phosphate distyrylphenyl dixylenyl phosphate and mixtures thereof.

The above mentioned compounds are meant to be illustrative only and are not intended to be an inclusive listi 55 The alkylphenyl phosphates employed in the present invention have the formula corresponding to:

lcbv l -l -@lcosities will be below 200 Saybolt Universal Seconds at 100 F. They are illustrate by the following: isopropylphenyl diphenyl phosphate, bis isopropylphenyl phenyl phosphate, diisopropylphenyl diphenyl phosphate, tertbutylphenyl diphenyl phosphate, sec-butylphenyl diphenyl phosphate, hexylphenyl diphenyl phosphate, octyl phenyl diphenyl phosphate and mixtures thereof. Isopropylphenyl diphenyl phosphate and the butylphenyl diphenyl phosphates are preferred.

The styrenated triaryl phosphates and alkylphenyl phosphates are blended in proportions of from about to about 90 percent by weight of the entire mixture of the styrenated triaryl phosphate and from about 90 to about 10 percent of the alkylphenyl phosphate. This blending is accomplished by any of the known methods for blending fluids. The viscosity of the blend will vary over a wide range depending upon the particular phosphates used and the proportions in which they are blended. Therefore, by varying the relative proportions of the two phosphates employed, a series of fluids having different viscosities can be obtained from only two components. Normally, these fluids will have viscosities in the range of from about 100 to about 900 Saybolt Universal Seconds and preferably from about 220 to about 600 Saybolt Universal Seconds at 100 F.

The fluids of the present invention are characterized by exceptionally high oxidative stability, low pour points, high autoignition temperatures and relatively high viscosity indices when compared with the fluids known in the art. Furthermore, the fluids of the present invention exhibit excellent flame retardancy and hydrolytic stability.

The fluids of the present invention can also contain minor amounts of other additives which are well known in the art. While, the fluids of the present invention have excellent oxidative stability by themselves, this property can be enhanced by the addition of any of the commonly used antioxidants such as the aryl amines, alkyl phenols, naphthyl amines, and alkylphenyl amines.

The naphthyl amines, such as phenyl-a-naphthyl amine and octylphenyl-a-naphthyl amine, and the alkyl phenyl amines, such as dioctyl diphenyl amine, are particularly useful antioxidants in the fluids of the present invention. These antioxidants are normally blended in amounts from about 0.1 to about 2 percent by weight. Rust inhibitors such as the polyhydric alcohols, alkyl malonic and succinic acids, amines, aminophenols and the polyvalent metal salts of organo sulfonic acid can also be incorporated in the fluids of the present invention. These rust inhibitors are also used in relatively small proportions, that is, from about 0.1 to about 2 percent by weight. Foam depressants can also be incorporated in the fluids.

The functional fluids of the present invention are deployed in closed hydraulic systems such as compressors, hydraulic lifts, deck edge elevators, brake systems, basic oxygen furnaces, die casting equipment, leveling devices or servo control units in such a manner that when pressure is applied to the fluid at a specific point within the confines of the hydraulic system, the pressure will be transmitted to every other point along the hydraulic system by the fluid.

The invention will be further illustrated by the following examples.

Example 1 Styrylphenyl bis(isopropylphenyl) phosphate was synthesized by reacting a commercially available styrenated phenol with phosphorus oxychloride in the presence of magnesium chloride, and then reacting the product so obtained with a commercially available isopropylated phenol. The product contained an average of approximately 0.7 styrylphenyl groups per molecule and had a viscosity of 1009 Saybolt Universal Seconds at 100 F. This styrenated phenyl bis(isopropylphenyl) phosphate was blended with the isopropylphenyl diphenyl phosphate in approximately 42 and 5 8 percent respectively by weight 4 of the entire composition. The fluid exhibited the properties contained in Table I.

Hot manifold (drip) ignition: Temperature F.) 1480 Shell 4 ball test (54 C., 600 r.p.m.):

10 kg. 0.30 40 kg. 0.50

Example 2 Styrylphenyl diphenyl phosphate was synthesized by reacting a commercially available styrenated phenol with phosphorus oxychloride in the presence of magnesium chloride and then reacting the product so obtained with phenol. The product contained an average of slightly greater than 1 styrylphenyl groups per molecule and had a viscosity of 1033 Saybolt Universal Seconds at F. This styrylphenyl diphenyl phosphate was blended with isopropylphenyl diphenyl phosphate in approximately 42 and 58 percent respectively by weight of the entire composition. The fluid exhibited the properties contained in ab e II.

TABLE II Viscosity (Saybolt Universal Seconds) At 100 F. 219 At 210 F. 44 Viscosity index 28 Acidity (mgs. KOH/gm.) 0.04 Autoignition temperature F.) 1120 Flash point F.) 275 Fire point F.) 650 Similar tests were conducted on a commercially available functional fluid sold under the tradename of Fyrquel 220 by Stauifer Chemical Company of New York. Fyrquel 220 is a triaryl phosphate based fluid having a viscosity of approximately 220 Saybolt Universal Seconds at 100 F. The fire properties were approximately the same for the styrylphenyl diphenyl phosphate fluid and Fyrquel 220 but the styrylphenyldiphenyl phosphate had a considerably higher viscosity index, thereby affordgig it a wider range of application than the commercial uid.

Example 3 The fluid employed in Example 2 was tested in a Vickers vane pump according to the procedure outlined in ASTM-D2271. A total volume of 9.5 gallons was employed and the temperature was maintained at F. under a pressure of 2000 p.s.i. The results are contained in Table III.

TABLE III Total ring Total vane Acid number weight weight Viscosity (m m. Time, hours loss (grn.) loss (gm.) (S.U.S.) KOH/gm.)

Table III demonstrates that the fluids of the present invention maintain their viscosity and acidity characteristics within close tolerances over long periods of continuous use with very little corrosive eflect on the equipment.

Example 4 A series of fluids were prepared by varying the proportions of the styrylphenyl diphenyl phosphate and the isopropylphenyl diphenyl phosphate employed in Example 2.

The relative proportions are contained in Table IV. TABLE IV Isopropylphenyl diphen- Styrylphenyl phosphate Viscosity diphenyl phosphate (percent by 100 F. (percent by weight) weight) (S.U.S.)

All of the blends in Table IV exhibit relatively low acidity, high viscosity and comparable fire properties when compared with commercial fluids having similar viscosities.

What is claimed is:

1. A synthetic hydraulic fluid composition consisting essentially of:

(a) from about 10% to about 90% by weight of the entire composition of a styrenated triaryl phosphate having the formula corresponding to:

(T1): H 1 2)!) o I" l H O -o- P J. L

wherein x is a number from about 0.5 to about 2.0

wherein R is an alkyl group having, from 3 to about 12 carbon atoms, d is a number from 1 to 5 inclusive, and y is a number from about 0.2 to about 2.5 inclusive; said composition having a viscosity in the range from about 100 to about 900 Saybolt Universal Seconds at 100 C.

(Rah

2. The composition of claim 1 wherein n is '1 and x is a number from about 0.7 to about 1.5.

3. The composition of claim 1 wherein the styrenated triaryl phosphate is styrylphenyl diphenyl phosphate. 5 4. The composition of claim 1 wherein the styrenated triaryl phosphate is styrylphenyl bis(isopropylphenyl) phosphate.

5. The composition of claim 4 wherein the alkylphenyl phosphate is isopropylphenyl diphenyl phosphate.

6. The composition of claim 1 wherein the alkylphenyl phosphate is chosen from the group consisting of tertbutylphenyl diphenyl phosphate and sec-butylphenyl diphenyl phosphate.

7. A process for the transmission of pressure in a hydraulic system which comprises deploying within said hydraulic system an effective amount of a hydraulic fluid composition consisting essentially of:

(a) A styrenated triaryl phosphate having the formula corresponding to:

o Q 0 l 0 Ha/n .|x L 3-x wherein x is a number from about 0.5 to about 2.0 inclusive, n is a number from 1 to 3 inclusive, a and c are each numbers from 0 to about 5, b is a number from 0 to 4 inclusive, and R R and R are each alkyl groups having from 1 to about 8 carbon atoms; 30 and (b) An alkylphenyl phosphate having the formula 7 corresponding to:

wherein y is a number from about 0.2 to about 2.5 and R is an alkyl group having from 1 to about 12 carbon atoms; and applying pressure to said hydraulic fluid composition at any point in said system so as to thereby transmit the thus applied pressure throughout said system through the medium of said hydraulic fluid composition.

US. Cl. X.R.