US3532632A

US3532632A - Hydraulic fluids containing nonionic surface action agents and phosphate esters of nonionic surface active agents

Info

Publication number: US3532632A
Application number: US615063A
Authority: US
Inventors: Jeal Sugarman; Fred E Woodward
Original assignee: GAF Corp
Current assignee: GAF Corp
Priority date: 1967-02-10
Filing date: 1967-02-10
Publication date: 1970-10-06
Anticipated expiration: 1987-10-06

Description

United States Patent HYDRAULIC FLUIDS CONTAINING NONIONIC SURFACE ACTION AGENTS AND PHOSPHATE ESTERS 0F NONIONIC SURFACE ACTIVE AGENTS Jeal Sugarman, Flushing, N.Y., and Fred E. Woodward,

Watchung, N.J., assignors to GAF Corporation, a corporation of Delaware No Drawing. Filed Feb. 10, 1967, Ser. No. 615,063

Int. Cl. C09k 3/00, 3/02 US. Cl. 252-75 6 Claims ABSTRACT OF THE DISCLOSURE A water-in-oil emulsion hydraulic fluid comprising about a 20 to 60% by weight water phase and about a 40 to 80% by weight oil phase, wherein said emulsion also contains (I) about 0.5 to 10% by weight based on the weight of the oil, of a mixture of monoand diphosphate esters and salts thereof and (II) about 0.5 to 10% by weight based on the weight of the oil, of a polyoxyethylene ether of an aliphatic alcohol surface active agent.

BACKGROUND OF THE INVENTION This invention relates to new and useful invert (waterin-oil) emulsions and more particularly to invert mineral oil emulsions which are outstanding lubricating and hydraulic fluids. This invention is especially concerned with fire resistant hydraulic fluids which have outstanding lubricity and stability characteristics.

The conventional hydraulic fluid is a petroleum oil which is an excellent fluid for this function when properly formulated with suitable corrosion inhibitors, antioxidants, extreme pressure additives, etc., but it suffers from the one major deficiency of flammability. Recently, considerable efforts have been directed toward the development of hydraulic fluids to replace such oils by developing fluids which retain the beneficial properties of the oil, but which would be essentially fire resistant and have good stability. An acceptable hydraulic fluid should have the following characteristics:

(1) Optimum hydraulic efliciency (2) Excellent lubrication (3) Corrosion protection (4) No effect on seals in hydraulic systems (5) Stability (6) Low flammability (7) Low cost Properly formulated petroleum oils are excellent hydraulic fluids, however, they have the distinct drawback of being etxremely flammable. Serious fires have been caused by hydraulic lines rupturing and the subsequent release, under high pressure, of the oil onto molten metal in die casting operations or the oil coming into contact with heated parts or sparks from electrical equipment, causing ignition of the oil. This serious hazard has led industry 'to initiate programs in changing over to fire resistant hydraulic fluids particularly in coal mines as well as in various other obvious industrial applications.

Three types of fire resistant hydraulic fluids have been reported. They are:

(1) Straight synthetic liquids of the organic phosphate ester type (e.g., tricresyl phosphate).

(2) Water-glycol fluids generally based on polyethylene glycols.

(3) Water-in-oil (invert) emulsions.

While the first two types normally exhibit good lubricity and wear properties, they are quite expensive and vary in their fire resistant and stability properties. The

3,532,632 Patented Oct. 6, 1970 third type has opened up a new horizon in this field. The use of water-in-oil (invert) emulsions allows the oil to remain in a continuous phase so that the hydraulic fluid may retain and exhibit the beneficial anti-corrosion and lubricating properties of the oil while also being resistant to flammability as well. However, merely emulsifying a petroleum oil with water fails to yield an emulsion of adequate lubricating qualities or stability, especially at high pressures.

It has now been discovered that stable, water-in-oil emulsions can be prepared having outstanding fire-resistaht, lubricity and wear properties by the employment of the instant invention.

It is therefore an object of the present invention to provide new and useful water-in-oil emulsions. It is another object of this invention to provide new and useful water-in-oil emulsions which are outstanding hydraulic fluids. It is still another object of the present invention to provide new and useful water-in-oil emulsions which have outstanding lubricating characteristics. It is a further object of this invention to provide new and useful water-in-oil emulsions which are stable and fire resistant under heat and pressure. Other objects, advantages and applications of the instant new and unobvious water-in-oil emulsions of the instant invention will be readily apparent from the following detailed description as well as the appended claims.

SUMMARY OF THE INVENTION The disadvantages of the prior art are overcome and the forementioned as well as other objects of the instant invention are accomplished according to the present invention by providing Water-in-oil emulsions which comprise from about 20-60% by weight water and from about 40-80% by weight oil, to which has been added (I) from about 0.5% to about 10% by weight based on the weight of the oil, of a mixture of phosphate esters and salts thereof of a nonionic surface active agent hereinafter to be described and (II) about 0.5 to about 10% by weight based on the weight of the oil, of a nonionic surface active agent derived from an aliphatic alcohol also to be further described.

The mixture of phosphate esters of nonionic surface active agents which is herein contemplated is a mixture of oil-soluble or oil-dispersible monoand diphosphate esters and salts thereof. The nonionic precursors for said esters are selected from the group consisting of polyoxyalkylene ethers of alkyl phenols and aliphatic alcohols ranging from at least 8 carbon atoms to about 70 carbon atoms, derived by condensing the alcohols with an alkylene oxide such as ethylene oxide, propylene oxide or butylene oxide or mixtures thereof. Thus, said oxyalkylene groups may contain from 2 to 4 carbon atoms each. The amount of oxyalkylene groups may vary from about 10% (i.e., derived from the interaction of 1 mole alkylene oxide) up to about 47 weight percent to weight percent (depending upon the oxyalkyl groups) based upon the weight of the nonionic. For example, the maximum weight percent of oxyalkylene when ethylene oxide is utilized is about 47 weight percent, while it is about 60 weight percent for propylene oxide and about 75 weight percent for butylene oxide. The ratio of mono phosphate ester to diphosphate ester in the above mentioned mixture is not critical, since any mixture amounting from about 0.5% to about 10% by weight based on the weight of the oil may be used.

The nonionic surface active agent derived from an aliphatic alcohol, which is present in the water-in-oil emulsion in addition to the phosphate esters, acts as an auxiliary emulsifier. It has been surprisingly discovered that the presence of this additional surfactant contributes the unobvious effect of making the water-in-oil emulsion very stable.

The nonionic surface active agent which is to be used in combination with the above described phosphate esters is extremely critical in obtaining a satisfactory, stable, invert emulsion. The nonionic surface active agent must be one which is dervied from an aliphatic alcohol of C to C condensed with from about 1.0 to about 3 moles of ethylene oxide, and preferably 1.5 to 2.5. Suitable alcohols include dodecyl alcohol, tridecyl alcohol, tetradecyl alcohol, pentadecyl alcohol, hexadecyl alcohol, stearyl alcohol, oleyl alcohol, primary-m-eicosyl alcohol, tricosyl alcohol, and n-tetracosyl alcohol. In addition to such alcohols, various naturally occurring mixtures which predominate in these alcohols may be used such as the mixed coco alcohols, tallow alcohol and the like.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The nonionic oxyalkylated products which are herein contemplated as precursors for the phosphate esters are well known in the art and are derived by reacting alkyl phenols or aliphatic alcohols of at least 8 carbon atoms with alkylene oxide as, for example, disclosed in US. Pats. 2,213,477 and 1,970,578. The preferred alkyl phenols are those having an alkyl or a plurality of alkyl substituents having a total of at least 8 carbon atoms in the alkyl chain or chains. The preferred aliphatic alcohols are those having above about 12 carbon atoms in the molecule. The following illustrate some typical suitable phenols and alcohols which may be used to form the corresponding nonionic surface active agents which are precursors for the instantly contemplated phosphate esters:

octyl phenol (diisobutylene) nonyl phenol (nonyl derived from propylene trimer) dodecyl phenol (derived from propylene tetramer) dibutyl phenol diamyl phenol hexadecyl phenol octadecyl phenol, and the like phenols containing a plurality of different alkyl groups, for example:

butyl amyl phenol butyl hexyl phenol amyl hexyl phenol amyl heptyl phenol ethyl heptyl phenol as well as phenols containing a plurality of similar alkyls such as, in addition to those above:

di-n-hexyl phenol diisohexyl phenol di-n-heptyl phenol di-n-octyl phenol diiso-octyl phenol dinonyl phenol didodecyl phenol ditetradecyl phenol diocta decyl phenol tri-n-octyl phenol trioctadecyl phenol tri-n-butyl phenol, and the like, as well as n-octyl alcohol iso-octyl alcohol n-nonyl alcohol n-decyl alcohol undecyl alcohol lauryl alcohol tridecyl (oxo) alcohol tetradecyl alcohol pentadecyl alcohol hexadecyl alcohol stearyl alcohol oleyl alcohol mixed coco alcohols hydrogenated tallow alcohol ROH alcohols prepared from olefins of C to C by the 0x0 process, i.e., addition of H C=O and hydrogenation to the alcohol: benzyl alcohol, substituted benzyl alcohols,

where R is C to C $113 RfiNHCHGHzOH where R is C, to C CHzCHzOH where R is C to C and the like.

The above compounds may be easily reacted with the alkylene oxide as described above to yield the nonionic surface active agents which are then used to prepare phosphate esters employed in the compositions of the present invention.

In addition to the oxyalkylated derivatives of the afore mentioned compounds, other oxyalkylated derivatives that may be employed, if desired, are the oxyalkylated derivatives of thio-alcohols, amides, sulfonamides and the like which have a reactive hydrogen atom capable of reacting with an alkylene oxide to yield an hydroxy compound which, like the compounds listed above, can also be phosphated.

One of the methods for preparing suitable phosphate esters employed in the instant invention, involves the reaction of 1 mole of P 0 with 2 to 4.5 moles of the nonionic surfactant as described and claimed in US. Pat. 3,004,056 by Nunn and Hesse and US. Pat. 3,004,057 by Nunn. As described in said Nunn and Hesse patent, the reaction between the P 0 and the nonionic polyoxyalkylene ether is conducted under substantially anhydrous conditions and at a temperature below about C. In its preferred form, the reaction is carried out by adding the P 0 gradually, with vigorous agitation to the nonionic surface active agent in liquid form. The reaction is exothermic and cooling is in some cases necessary to keep the temperature below 110 C., since discolored and darkened products tend to be produced above this temperature. The reaction proceeds continuously during the addition of the P 0 and is preferably followed by maintenance of the reaction mixture at ambient temperatures up to 110 C. for an additional period of time after completion of such addition to allow for complete solution of the P 0 and reaction with the nonionic surface active agent.

By carrying out the above reaction in the presence of a small amount of a phosphorous-containing compound, selected from the group consisting of hypophosphorous acid, salts of hypophosphorous acid, phosphorous acid, and salts and esters of phosphorous acid, preferably sodium hypophosphite or hypophosphorous acid, as described in said Nunn '057 patent, lighter colored or substantially colorless reaction products are obtained.

Monoesters and diesters can also be prepared from the corresponding triesters by reacting the triester with phosphoric acid. By varying the ratio of nonionic to acid, one can prepare either monoor diester to the substantial exclusion of the other. A high ratio of triester to acid (2:1) produces diester, whereas a low ratio (0.5 :1) produces monoester. It is also obvious that the mixture of phosphate esters may be readily prepared by merely combining one or more monophosphate esters with one or more diphosphate esters.

Thus, the monoand di-phosphated products may be represented by the following formulas:

R CHCHzO -OI OX (3 t. and

wherein R represents H, or methyl; X may be hydrogen, alkali metal, alkaline earth metal, e.g., calcium, magnesium, barium, etc., ammonium or substituted ammonium, and n equals the number of moles of alkylene oxide necessary to yield a final product containing up to 75% by weight of the said alkylene oxide as discussed above; R is the alcohol or phenol hydrophobe nucleus.

The following examples are illustrative of the present invention and are not to be regarded as limitative. It is to be understood that all parts, percentages and proportions referred to herein and in the appended claims are by weight unless otherwise indicated.

Example I A mixture of monoand di-phosphate esters are prepared by reacting 2.7 moles of a nonionic surface active compound derived from dinonyl phenol condensed with 7 moles of ethylene oxide with 1 mole of P 0 in the manner described in the examples of US. Pat. 3,004,056.

In general, procedures for preparing the subject emulsions involve dissolving the selected phosphate ester and the nonionic surface active agent in the selected oil and thereafter adding water slowly with sufficient stirring, whereby a water-in-oil emulsion is formed.

Example II (A) Preparation of phosphate ester barium salt: 50 g. of the phosphate ester of Example I above are dissolved in 50 g. of Esso Base F Oil which is a non-solvent refined neutral oil with a KB value=l9.l. 17.0 g. of barium hydroxide-H O are then added and the mixture is stirred until uniform. The resulting product is an opaque viscous liquid, the pH of a 1% solution of which in distilled water is 9.3.

(B) Preparation of water-imoil emulsion: To 53.1 g. of Esso Base Oil F there are added 5.9 g. of the liquid prepared in Part A above and 1 g. of the nonionic surfacant derived from the condensation of oleyl alcohol with 3 moles of ethylene oxide. The mixture is stirred until a uniform product is obtained. 40 g. of water are then slowly added with high speed propeller stirring. An especially smooth, stable, non-flammable, white water-inoil emulsion is formed.

After standing 14 days at 90 C., two thirds of the emulsion separated into a clear oil phase on top with one third of the emulsion remaining intact. However, on shaking, the water-in-oil emulsion was easily re-fonmed. No water separation was ever noted. This demonstrates that under the constant agitation of a pump, the water-in-oil emulsion, when in actual use, will remain very stable and completely intact.

Example III Example II is repeated except that the nonionic surfactant employed in Part B is a condensation product of tallow alcohol plus 2 moles of ethylene oxide which yields like results.

Example IV (A) The procedure of Example I is repeated using dodecyl phenol which has been condensed with 7 moles of ethylene oxide.

(B) To 51 parts of Solvent-Refined Midcontinent Oil (150 SUS, neutral) there are added 1.5 parts of the phosphate ester of Part A above and 4.0 parts of the nonionic surfactant described in Example III.

(C) To 43 parts of water there are added 0.5 part of barium hydroxide .8 H O.

(D) The aqueous solution of Part C is then slowly added to the oil prepared in Part A with stirring. An outstanding stable, non-flammable, water-in-oil emulsion is produced.

Example V (A) Example I is again repeated except that the nonionic employed is derived from nonyl phenol condensed with 1.8 moles of ethylene oxide.

(B) To 54 parts of the oil described in Example IVB there are added 2 parts of the phosphate ester of Part A above and 1 part of the nonionic also described in Example IVB.

(C) To 43 parts of water there are added .24 part of calcium hydroxide.

(D) Parts B and C are mixed as in Example IV to produce an excellent stable, non-flammable, water-in-oil emulsion.

Example VI Example V is repeated except that 53 parts of oil are used in Part B and 2 parts of the nonionic are employed instead of 1 part which yields like results.

Like results may also be obtained by replacing the above employed phosphate esters with mixtures of mono and diphosphate esters derived from the following polyoxyalkylene compounds:

dinonyl phenol+4 moles ethylene oxide dodecyl phenol+2 moles ethylene oxide dinonyl phenol-l-S moles ethylene oxide dinonyl phenol+1.5 moles ethylene oxide dodecyl phenol+1.8 moles ethylene oxide octadecanol+2 moles ethylene oxide hexadecanol+4 moles ethylene oxide l-eicosanol+6 moles ethylene oxide l-dotriacontanol-l-7 moles ethylene oxide dodecyl phenol-I-S moles ethylene oxide hexadecyl phenol+3 moles ethylene oxide tri-n-octyl phenol+ r moles ethylene oxide tri-n-octyl phenol+5 moles propylene oxide dodecyl phenol+3 moles propylene oxide dinonyl phenol+1.5 moles propylene oxide diisohexyl phenol+2 moles propylene oxide tri-n-butyl phenol+2 moles propylene oxide tri-n-butyl phenol+3 moles propylene oxide trim-butyl phenol+2 moles ethylene oxide+2 moles propylene oxide tri-n-butyl phenol+3 moles ethylene oxide hexadecanol+3 moles propylene oxide octadecanol+4 moles propylene oxide butyl hexyl phenol+4 moles ethylene oxide ethyl heptyl phenol+5 moles ethylene oxide ethyl heptyl phenol+3 moles propylene oxide ceryl alcohol+2 moles ethylene oxide 1-ocracosanol-i-4 moles ethylene oxide 1-nonacosanol+7 moles ethylene oxide 1-triacontanol+6 moles ethylene oxide l-tetratriacontanol-l-S moles ethylene oxide l-tetratriacontanol-i-Z moles propylene oxide and the like. Moreover, similar results may also be obtained by replacing the above employed nonionic surfactants with other aliphatic surfactants, such as,

dodecyl alcohol+2 moles ethylene oxide tetradecyl alcohol+3 moles ethylene oxide hexadecyl alcohol+1.5 moles ethylene oxide stearyl alcohol+l.5 moles ethylene oxide primary-m-eicosyl alcohol+l mole ethylene oxide n-tetracosyl alcohol+2.5 moles ethylene oxide and the like.

7 Example VII In order to demonstrate the wear and corrosion resistant properties of the instant water-in-oil emulsions, the following comparative test was carried out:

The amount of wear in a Vickers Vane type pump (Model V-104C, 8 gallons/minute delivery) was determined utilizing the Water-in-oil emulsion product of Example II as compared to the amount of wear utilizing a commercially available product, Iris 902 (Shell Oil Co.). The following data illustrates the wear properties of each fluid:

Water-in-oil emulsion of Example II:

Duration-267 hours Temperature6065 C. Pressure450500 p.s.i.

Rate of cam ring wear-2.61 mg./hr. Rate of vane wear0.303 mg./ hr.

Iris 902:

Durationl hours Temperature4550 C. Pressure450500 p.s.i.

Rate of cam ring wear5.1l mg./hr. Rate of vane wear0.415 mg./hr.

After the above test, the cam ring and vane of the experimental run utilizing the water-in-oil emulsion of Example II was found, upon visual inspection, to be clean and free from corrosion, pitting, etc.

Various modifications and variations of this invention will be obvious to a worker skilled in the art and it is understood that such modifications and variations are to be included within the purview of this application and the spirit and scope of the appended claims.

We claim:

1. A water-in-oil emulsion hydraulic fluid consisting essentially of from about a to about a 60% water phase and from about a 40% to about an 80% oil phase and to which has been added (I) from about 0.5% to about 10% by weight based on the weight of the oil, of a mixture of mono and diphosphate esters and salts thereof of the formulae wherein Alk represents an alkylene group selected from the group consisting of ethylene, propylene, and butylene,

R represents the residue of an alkyl phenol or aliphatic alcohol from 8 to about carbon atoms, X is selected from hydrogen, alkali metals, alkaline earth metals, ammonium or substituted ammonium, and n equals the number of moles of alkylene oxide such that the nonionic precursor of said mixture of monoand diphosphate esters and salts thereof contains a maximum of about 47 weight percent of ethylene oxide, a maximum of about 60 weight percent of propylene oxide and a maximum of about weight percent of butylene oxide depending upon the alkylene oxide used, and (II) from about 0.5% to about 10% by weight based on the weight of the oil of a nonionic surface active agent derived from the condensation of an aliphatic alcohol of from 12 to 24 carbon atoms with from about 1.5 to about 3.0 moles of ethylene oxide per mole of alcohol.

2. A water-in-oil emulsion hydraulic fluid as defined in claim 1, wherein ingredient (II), the nonionic surface active agent, derived from an aliphatic alcohol and ethylene oxide, is the condensation product of oleyl alcohol and 3 moles of ethylene oxide.

3. A water-in-oil emulsion hydraulic fluid as defined in claim 1, wherein ingredient (II), the nonionic surface active agent, derived from an aliphatic alcohol and ethylene oxide is the condensation product of tallow alcohol and 2 moles of ethylene oxide.

4. The water-in-oil emulsion hydraulic fluid of claim 1 wherein R is the residue of dinonyl phenol, Alk is ethylene, and X is barium.

5. The water-in-oil emulsion hydraulic fluid of claim 1 wherein R is the residue of dodecyl phenol, Alk is ethylene, and X is barium.

6. The water-in-oil emulsion hydraulic fluid of claim 1 wherein R is the residue of nonyl phenol, Alk is ethylene, and X is calcium.

References Cited UNITED STATES PATENTS 2,965,574 12/1960 Tierney et al 252-78 3,269,946 8/1966 Wiese 25278 X 3,311,561 3/1967 Anderson et al 252-78 X 3,004,056 10/1961 Nunn 260950 3,010,903 11/1961 Clarke et al. 260980 3,278,442 10/1966 Beerbower et al. 252-75 3,331,896 7/1967 Eiseman et al 260980 HERBERT B. GUYNN, Primary Examiner M. HALPERN, Assistant Examiner U.S. Cl. X.R. 25278, 498