US3222284A

US3222284A - Emulsion hydraulic fluid, concentrate and method of preparing same

Info

Publication number: US3222284A
Application number: US143314A
Authority: US
Inventors: George R Cook
Original assignee: Union Oil Company of California
Current assignee: Union Oil Company of California
Priority date: 1961-10-06
Filing date: 1961-10-06
Publication date: 1965-12-07
Anticipated expiration: 1982-12-07

Description

United States Patent 3,222,284 EMULSION HYDRAULIC FLUID, CONCENTRATE AND METHOD OF PREPARING SAME George R. Cook, Arlington Heights, 111., assignor, by

mesne assignments, to Union Oil Company of California, Los Angeles, Calif., a corporation of California No Drawing. Filed Oct. 6, 1961, Ser. No. 143,314 19 Claims. (Cl. 252-75) This invention relates to new compositions of matter, and more particularly to hydraulic fluid compositions. A specific feature of the invention is the discovery that certain critical relationships exist in the concentrations, types of ingredients, etc., in water-in-oil, emulsion-type hydraulic fluids. Another feature of the invention is the discovery that the ease of emulsibility, the blend stability in concentrated and diluted form, the attainment of suitable viscosities, and the viscosity stability of the diluted emulsion under shear of fire-resistant hydraulic fluids of the water-in-oil emulsion type are directly and critically influenced by the kind, amounts, and ratios of ingredients.

Fire-resistant hydraulic fluids may be pure synthetic materials, suchas phosphate esters, mixtures of phosphate esters, or various chlorinated materials, or may be mixtures of water and water-soluble synthetics or water-in oil emulsions, comprising a second and more recent type of snuifer fluids. This latter type, to which this invention relates, offers excellent fire resistance due to the release of a blanket of steam in the presence of high temperature. These emulsion-type fluids offer excellent fireresistance, acceptable lubricity, corrosion resistance, hydraulic efficiency, adequate film strength, high viscosity index, oxidation stability, good cooling qualities, and compatibility with equipment. As a result, emulsion-type fluids are being used more extensively in systems operating at high temperatures and pressures Where fire-resistance is important, such as in the hydraulic machinery in ships at sea, submarines, wind tunnels, mining equipment, missile launching, and in machinery handling hot ingots or molten metals, or operating near sparks, flames, or hot metal surfaces. Some hydraulic systems operate at temperatures as high as 650 F. and pressures as high as 3000 p.s.i. Standardized tests have been developed for fire-resistance, namely, the high-temperature test (pressure-ignition spray test), the hot manifold test, and the pipe-cleaner test under Specification MIIr-FJIOO. In addition to these criteria, hydraulic fluids must be devoid of toxic effects, must not harm metals or seals, should not foam or cause erosion, and must be compatible with machinery paint.

The development of water-in-oil, emulsion-type hydraulic fluids meeting these severe demands is diflicult because these fluids must also be stable in concentrate form, be easily emulsified, and form stable emulsions having suitable viscosities and viscosity stabilities as evaluated by the Vickers pump test. This test was developed by the industry in cooperation with the Bureau of Mines to evaluate the emulsion stability under shear, simulating the conditions imposed in modern hydraulic machinery, particularly for use in mining operations. The operating conditions are 1000 to 2000 p.s.i. at flow rates of at least 2.0 to as high as 8.0 gallons per minute for 1000 hours. These tests may be conducted at pressures as high as 10,000 p.s.i.

To pass the Vickers pump test, the hydraulic fluid must not 3,222,284 Patented Dec. 7, 1965 ice break down or permit excess wear of pump parts over the 1000-hour test period. Although no limits on the weight loss to be tolerated have been established, a total weight loss of 0.0300 gm. is considered excellent. Also, the fluid is evaluated for adequate cooling of the system and for uniformity of viscosity throughout the time of the test. Another feature of this invention is the development of an emulsion-type hydraulic fluid which not only meets'the general requirements aforesaid, but also passes the Vickers pump test.

Accordingly, a primary object of this invention is to provide fire-resistant hydraulic. fluids. of the water-inroil emulsion type. V

An object of this invention is to provide fire-resistant hydraulic fluids of the water-in-oil emulsion type which meet the general requirements for hydraulic fluids in addition to qualifying for use at high pressures and(or high temperatures. a

Another object of this invention is to provide fire-resistant hydraulic fluids of the water-in-oilemulsion type.

which exhibit emulsion stability in dilute and concentrated bility in diluted form under extreme pressure conditions,

as evaluated by the Vickers pump test, in addition to meeting the other requisites for such a fluid.

These and other objects of this invention will be described or become apparent as the specification proceeds.

Many unique problems have been found to be associated with the formulation of water-in-oil emulsions, and concentrates for their preparation, for use as fire-resistant hydraulic fluids. For example, in evaluating and screening a large number of fluids, it was found that the water" content (which is all-important in the stability of solubleoil emulsions of the O/W type) plays no part in the problems of W/O emulsion stability. The use of various mutual solvents or couplers such as diethylene glycol, hexylene glycol, butyl Cellosolve, etc.,' which are known to be effective stability enhancers in O/ W emulsions, offered no solution to the problem in W/O emulsions. Furthermore, various known emulsifiers such as polyoxyethylene derivatives of fatty acids, esters of fatty acids, alkyl aryl sulfonates, and various surfactants, gave satisfactory emulsions with 40% of water, but the emulsions failed the Vickers pump test due to their breakdown. Additives re ported to be useful for enhancement of lubricity or antiwear were evaluated and found to be ineffective or detrimental. By experiments With W/O emulsions, it was determined that the viscosity of the oil in the emulsion had little, if any, effect upon the apparent viscosity of the emulsion. Bright stocks, however, are excluded as the base oil because of their inherently high viscosity. Distillate oils, such as neutral oils, form the best base oil. With a corresponding water content, the substitution of a 2000-vis. neutral for a IOO-Vis. neutral gave emulsions of practically the same viscosities.

I have found that by combining certain types of petroleum sulfonates in particular proportions with certain metal alkyl dithiophosphates in particular proportions, and combining this mixture at certain over-all concentrations with distillate mineral oils, e.g., with neutral oils, concentrates exhibiting the desired stability, and emulsions therefrom meeting the severe Vickers pump test and other requirements heretofore mentioned, can be obtained. The invention is more particularly described in relation to a number of examples which are to be considered exemplary and not limiting on the scope thereof.

Table I sets forth the composition of this invention in weight percent based on the additives, active ingredients and on a W/O emulsion blend thereof.

Table i A. COMPOSITE OF CONCENTRATE BASED ON ADDITIV'ES Weight Percent Low Optimum High range Additive:

Commercial alkali metal petrol sulfonate 2. 50 3. 45-5. 19 6. Commercial alkaline earth metal alkaryl sulfonate 1. 00 1. 40-3. 36 4. 51 Commercial metal dialkyl dithiophosphate 0.49 0. 92-1. 00 1. 50 Mineral lubricating oil (balance) B. COMPOSITION OF CONCENTRATE BASED ON AC" TIVE INGREDIENTS Ingredient:

Alkali metal petroleum sulfonate... 1. 55 2 14-3. 22 3. 72 Alkaline earth metal alkaryl sulfonate 0. 45 0 63-1. 51 2.03 Metal dialkyl dithiophosphate 0.47 0 88-0. 95 1. 43 Mineral lubricating oil (balanee) C. COMPOSITION OF W/O EMULSION (60% CONC.-|40% H2O) OF B In Table I, the concentration of the mineral oil has been omitted to avoid the implication that in each part of the table the concentrations appearing one over the other in a column are used to formulate a composition of this invention. Table I is intended to give the range of concentration of each ingredient that can be used in the overall concentrate, for example, the ratio of concentrations in weight percent alkali metal sulfonate to alkaline earth metal sulfonate is broadly between about 1.55/ 2.03 or .71 to 3.72/.45 or 8.26, and preferably about 3.22/0.63 or 5.27 to 2.14/1.51 or 1.4, and further provided that the total amount of said sulfonates is greater than about 2.77 (2.14+0.63) and less than about 4.73 (3.22|1.51) weight percent. Preferably, the range of the total amount of said sulfonates is about 3.50 to 3.80 with the preferred amount being about 3.65 weight percent.

In making up concentrates using commercially available alkali metal sulfonates and alkaline earth metal sulfonates, as further herein defined, appropriate adjustments in the amount of commercial addend, which generally is obtained as a mineral oil solution, are made to take into account the mineral oil or other diluent that is present. The amounts of such oil or other diluents are taken into account in the mineral oil portion of the compositions. The concentrations of ingredients in all parts of Table I are subject to modification depending on the active ingredients, based upon precise chemical analysis, of the addends used and also upon the amount of water used to make the final W/O emulsion. The amount of metal shown provided the above-defined limitations regarding the ratio of sulfonates and total amounts of sulfonates are met. A broader range (based on active ingredients) of about 0.25 to 1.5 weight percent is specified for general service. The dithiophosphate additive may contain small amounts, in the order of 1.0% by wt. of sulfonates, to aid in solubilizing same in mineral oil. Since this changesthe total sulfonate content by only about 0.001% by weight at the most, it can be ignored.

The amount of water used to prepare the final W/O emulsion product is subject to some variation. The purpose of the water is to give fire-resistance properties to the product. According to the U.S. Bureau of Mines, between about 38% to 42% by weight of water gives the most consistent and safe fire-resistant qualities, with the optimum being about 40% by weight. These recommended amounts are varied throughout the industry depending on Whether the proportions are established on a volume percent or weight percent basis. Generally, a loss of about 5% by weight of water causes a reduction in the fire-resistant qualities of the product. However, for many purposes adequate fire-resistance can be attained through the use of 25% by weight of water, with the balance being the mineral oil concentrate. There is some tendency for the emulsion to burn in a severe electric are when only 20% by weight of water is present, and at water concentrations above about 45% by weight, there is an increase in the apparent viscosity of the emulsion, causing cavitation in the pumps which results in failure to pass the Vickers pump test. Water concentrations below about 33% by weight do not give adequate fire-resistance for most purposes. Consequently, the water content of the emulsions contemplated by this invention can have values ranging from about 33 to 45% by weight, with the preferred concentration being 33 to 41% by Weight.

A preferred embodiment of this invention consists of a fire-resistant hydraulic fluid concentrate having the foregoing proportions comprising sodium petroleum sulfonate, calcium dodecyl benzene sulfonate, zinc dialkyl dithiophosphate, wherein the alkyl group contains 6 to 8 carbon atoms, and a neutral mineral lubricating oil of the MCSR variety.

In order to illustrate the invention, a series of experiments are described wherein a number of experimental emulsions were prepared using ditferent ingredients or addends, difiierent mineral oils, and waters coming from different sources. Initial experiments established that oilin-water emulsions preparedusing the best known commercial sulfonate-type detergents, emulsifiers, and coupling agents with preferred types of oil and distilled water could not pass the Vickers hydraulic pump test because of excessive wear of the pump parts, breakdown of the emulsion, or failure to allow the establishment of the required pumping rates. Some of these oil-in-water emulsions, though stable and meeting the initial viscosity requirements, exhibited a deterioration of viscosity during the tests and almost a complete breakdown at the conclusion of the tests. Examples I to V are illustrative.

EXAMPLE I A series of oil-in-water emulsions containing from about 40% to 50% by volume of concentrates and consisting of petroleum sulfonates (9.92% to 12.48% by wt. based on the additives), 1.98% to 2.51% polyethylene glycol esters, assisting agents such as oleic acid, 0.29% to 0.33%, and Mid-Continent solvent refined mineral lubricating oils (19.8% to 36.0%), with distilled water in amounts ranging from about 50.0% to 66.29%, were prepared, tested, and evaluated by means of the Vickers pump test. All of these oil-in-water emulsions failed the Vickers pump tests either because of poor pumping rates, the development of noise and excessive wear in the pump parts, loss of pump pressure, or for other reasons. This EXAMPLE II A series of water-in-oil emulsions and water dispersions was prepared containing as the emulsifiers such materials as petroleum sulfonates, glyceryl mono-oleate, and such assisting agents as hexylene glycol and highmolecular-weight alcohols, with and without metal dialkyl dithiophosphates, said materials being present in amounts adjusted to give stable water-in-oil emulsions when mixed with from 66% to 71% of MCSR oil and distilled water or with 63 to 84% distilled water. None of these compositions passed the Vickers pump test although the viscosities of the blends and their stabilities were above acceptable limits.

EXAMPLE III A water-in-oil emulsion containing 8.0% by wt. of polyethylene glycol 200 monolaurate, 4.0% polyethylene glycol 600 mono-oleate, 66.0% MCSR lubricating oil, and 22.0% distilled water was prepared. The emulsion had a viscosity at 100 F. of 876 SUS. At the conclusion of the Vickers pump test, which had a duration of three hours, the viscosity at 100 F. was 795 SUS and the pumping rate at the start of the test was 2.0 g.p.m. at 1000 p.s.i. This pumping rate dropped to 1.8 g.p.m. at 480 p.s.i. at the conclusion of the test and the required 1000 p.s.i. pressure could not be reached due to pump vibration. This composition failed the Vickers pump test.

EXAMPLE IV A concentrate and water-in-oil emulsion having the following composition in weight percent, on the basrs of the commercial additives, were prepared.

In preparing the concentrate, a base oil comprising 1.00% by wt. of the zinc dialkyl dithiophosphate, 66.73% 'SO/ I'OO F.N., and 32.27% 170/100 RN. Was' used. This base oil was 93.33% of the concentrate and 56% of the emulsion. Storage tests indicated this formulation to be highly acceptable as far as the stability of the concentrate and emulsion are concerned, but the emulsion was not sufficiently shear stable to withstand the rigorous action of the Vickers pump test, and the emulsions were unstable after pumping for a short time. This formulation failed the Vickers pump test.

EXAMPLE V A concentrate and water-in-oil emulsion having the following composition in weight percent, on the basis of the additives used, were prepared.

In preparing the concentrate, the base oil of Example IV was used and became 93.80% of the concentrate and Ingredients Emulsion Concentrate 56.28% of the emulsion. The concentrate and emulsion wt. percent Percent were extremely stable but the emulsion failed the Vickers pump test. Polyox ethylene sorbitan trioleate 1.08 1.80 sorbitgl partial fatty esters M2 L87 Attention was directed to water 1n oil emulsions, and Zinc dialkyldithiophosphate-- g. g. 40 after a series of screening tests and Vickers pump tests, 86 /28fitttfiittfititltttttir::::::: 18:07 301. the comp s Table I were esaiplished as W 40-00 illustrative of the invention as these compositions meet 100.00 100.00 the stability and performance tests, hereinafter more fully explained, for an =FRHF composition.

Table IA COMPOSITIONS OF FRHF CONCENTRATES AND EMULSIONS Blend No 12 13 14 Concentrate 60%-40% by wt. Concentrate 60%-40% by wt. Concentrate 60%-40% by wt,

emul. emul. emul.

Addenda Act. Addends Act. Addends Act. Addends Act. Addenda Act. Addends Act.

Ing. Ing. Ing. Ing. lug. Ing.

mgredtileintsz P t l S If t e so um e to em H mm 4. 00 2. 48 2. 40 1. 49 5. 20 3. 22 3. 12 1.93 3. 2.14 2. 07 1.28

5 0. 93 0. 88 0. 56 0. 53 0. 93 0. 88 0. 56 0. 53 1. 00 0. 95 0. 60 57 80/100 Neutral (Oil No. 1)- 62. 30 63. 80 37. 38 38. 28 170/100NNeutral ((0)il lggvggfh 30. 17 31. 67 18.10 19. 00

100 Neut 1 20 LSWT 611100, 15 30. 17 31. 57 18.10 18. 94 100 Pale Oil (No. 3) 92.19 95. 40 55. 31 57. 24 13-1? Neutral (Oil N0. 5) I (92.19) (95. 40) (55. 31) (57. 24) Water 40.00 40. 00 40. 00 40. 00 40. 00 40, 00

7 The B-P neutral oil, No. 5, was substituted for the 100 pale oil in the concentrates and emulsions of Blend No. 14, which values are shown in parentheses. Taking into N0. 12 of Table IA, a further comparison was made with two commercially available hydraulic fluids purported to be suitable for use in mining equipment. The results are account the amount of ISW I oil in Blend No. 12, and shown in Table II.

Table II COMPARISON OF VICKE RS HYDRAULIC PUMP TEST DATA AT 1,000 P.S.I.

Product Blend N0. 12 FRIIF A FRIIF B Table I Type W/O Emulsion W/O Emulsion W/O Emulsion Total pumpage durng 1,000 hr. test (gals) 128,698 113,181 120,223 Total Average Flow Rate (g.p.rn.) 2.15 1.89 2.00

Type of loss Mg. Percent Mg. Percent Mg. Percent Front Bushing 20. 7 0. 0118 33. 8 0. 0189 26. 1 1 0. 0140 Rear Bushing. 20. 7 0. 0119 37.1 0. 0207 25. 2 1 0. 0141 Rotor 22. 0. 0068 11. 0 0. 0034 53. 0 1 0. 0163 Ring- 257. 0 0. 1165 406. 0 0.1834 256. 0 l 0. 1158 Vanes and Pin 162. 8 0. 4384 803. 4 I 2. 1138 100. 0 1 0. 2688 Total loss 483. 2 0.0518 1, 291. 3 0. 1371 460. 3 1 0. 0491 1 These results were subject to question due to the disintegration of a cork float in the safety circuit. The cork was trapped in the filter but could have changed the properties of the fluid to appear more favorable in the pump test.

Referring to Table II the FRHF A would be considered borderline and Blend No. 12 is shown to have successfully passed the Vickers pump test.

Since one of the crtical factors in formulating fire-resistant hydraulic fluids is the rubber-seal test, the example Blend No. 12 was evaluated in accordance with ASTM D471 Method at 158 F. The results are shown in Table IH.

Table III RUBBER-SEAL TEST CONDUCTED WITH FIRE-RESISTANT HYDRAULIC FLUID CON Rubber Specimens:

CENTRATE AND EMULSION Chicago Rawhide (Sirvene) Manufacture, Buna N-Type A 2. Vickers Model 104-E-10 Pump Shaft Seal, part No. 188323 (presumably Buna N) FRHF type Concentrate (Blend No. 12) Emulsion glend No. 12 in Rubber Specimen Number 1 2 1 2 Run 1 Run 2 Run 1 Run 2 Run 1 Run 2 Run 1 Run 2 Durometer (Hardness Value):

Initial value 92 92 After hours 92 89 After 168 hours 90 86 After 28 days 92 83 Thickness (inches):

Initial value 061 After 70 hours 061 After 168 hours 0615 After 28 days 061 Volume Change (percent):

After 70 hours 0 1 nil 0.5 7.5 9.9 8 6 12.9 1 6 After 168 hours 0 5 nil 4.3 7. 5 9. 2 8 9 13.5 4 7 After 28 days 0 4 1111 3.3 14.6 8.1 16 4 14.1 4 7 TEST NOTES:

1. None of the seals showed any tendency to crack when bent back upon itself. 2. Those seals used with the FRHF emulsion were more pliable at end of test period than those tested in the concentrate.

3. No thickness or hardness measurements could be taken on Pump Shaft Seals.

the other containing 33.66% by weight of 80/ neutral, 14.46% by weight of 170/100 neutral, and 7.36% by wt. ISWT oil, are shown in Table IA and are additional examples of emulsions within the scope of this invention.

In order to obtain a more critical evaluation of Blend In order to further establish the unique physical properties of the fire-resistant hydraulic fluids of this invention, Blend No. 12 was further independently evaluated with the Vickers pump test at a higher pressure, namely 1500 75 p.s.i.g. The results are shown in Table IV.

Table IV HYDRAULIC PUMP TEST AT 1500 P.S.I.G.

Pump Type: Vickers Vane Type, Model 105-010, Designed flow rate7.5 to 8.0 g.p.m. (450 to 480 g.p.h.) Sample: 60% (wt) Blend No. 12 and 40% (wt.) water (a water-in-oil emulsion was formed) Test Hours, Cumulative 116. 250 374 510 605 700 800 901. 5 1,013 Test Hours, Periodic 0 116. 5 133. 5 124 136 95 101. 5 111.5 Gallonage Pumped, Cumulative- 53,907 115, 945 171,697 233,265 273,622 313,800 356,403 400,327 448, 401 Gallonage Pumped, Per1odic 53, 907 62, 038 55, 752 61, 568 40, 357 40,178 42, 603 43, 924 48,074 Flow Rate (g.p.h.), Gnmulative 462. 7 463.8 459. 1 457.4 450.8 448.3 445.5 444.6 442. 6 Flow Rate (g.p.h.), Periodic 462. 7 464. 6 448. 8 452. 7 424. 8 422. 9 426. 0 432. 8 431. 2 Operat ng Pressure (p.s.i.g.) 0 1, 500 1, 500 1,500 1, 500 1, 500 1, 500 1, 500 1, 500 1, 500 Operatmg Temperature F.) 15 150 15 150 185 185 185 185 185 Test Data Obtained:

Viscosity at 100 F. (SUS) 349 364 367 355 351 367 409 390 416 398 Viscosity at 150 F. (SUS) 144 148 146 145 141 148 162 158 168 Viscosity at F. (SUS) 89 98 87 96 89 Percent Water (by volume) 36. 35 35. 0 35. 5 35. 0 35.0 34.0 35. 0 36. 0 37. 4 39 Miscellaneous: The following additions of fluid were made- At 650 hours, 2 qts. concentrate and 4 qts. water. At 810 hours, 4 qts. concentrate and 4 qts. water. At 965 hours, 4 qts. concentrate and 4 qts. water.

Weight (grams) Weight Loss (grams) Parts Percent of Loss From start to From Start to Start At 510 Hours At 1,013 Hours From start to From 510 hrs. finish at 1,013 Finish 510 hrs. to 1,013 hrs. hrs.

183. 0372 183. 0002 182. 9528 0. 0370 0. 0474 0. 0844 0. 0461 177. 2394 177. 2094 177. 1881 0. 0300 0. 0213 0. 0513 0. 0289 182. 4314 180. 5610 180. 3330 1. 8704 0. 2280 2. 0984 1. 1502 323. 1153 322. 6431 322, 4030 0. 4722 0. 2401 0. 7123 0. 2205 Vanes and Pin 37.8296 37. 4766 37.1547 0.3530 0.3219 0. 6749 1. 7841 903. 6529 900. 8903 r 900. 0316 2. 7626 0. 8587 3. 6213 Percent weight loss 0. 305 0. 095 0. 401

Blends. 13 and 14 and the two additional blends containing ISWT oil, when similarly tested, pass the Vickers pump test at pressures up to 1500 p.s.i.g., the flammability tests, and the rubber-seal test, and exhibit acceptable stability in concentrate and emulsion form in addition to passing the other requirements for fire-resistant hydraulic fluids.

FLAMMABILITY Table V The results shown in Table IV indicate that the compositions of this invention have exceptional properties as evaluated by the Vickers pump test.

Table V gives the results of flammability tests on Blend No. 12.

TESTS CONDUCTED WITH 60% BLEND NO. 12 AND 40% WATER FORMING A WATE R-IN-OIL EMULSION [1. Federal Test Method Standard 352-T, Efiect of Evaporation on Flammability ipe Cleaner Test)] Sample: Emulsion taken from Hydraulic Pump Test reservoir at start of test.

Sample: Emulsion taken from Hydraulic Pump Test reservoir after 1,013 hrs. of testing.

Average Minimum Acceptable--.

5:6 (Pass) 24 51 (Pass) is 23.8 (Pass) 12 [2. 13.8. BUREAU OF MINES FLAMMABILI'IY TEST] Sample: Emulsion taken from Hydraulic Pump Test reservoir at start of test. Spontaneous Ignition Temperature of Emulsion, 745 F. (600 F. Minimum Required.)

Conditions: A spray test at 150 p.s.i. and fluid temperature of 150 F.

N.b. These tests were also conducted with samples drawn from the hydraulic pump test at approximately IOU-hour intervals. The results obtained were essentially the same as those reported herein.

A number of other fire-resistant hydraulic fluid emulsions prepared using the concentrations of ingredients set forth herein also pass the flammability tests shown in In order to establish the essential, critical nature of the proportions of alkali metal petroleum sulfonate and alkaline earth metal sulfonates, a number of compositions Table V.

In evaluating a number of concentrates and emulsions within and outside of the essentially critical limits of addend concentration, I found that the concentrates were generally stable and emulsions prepared therefrom, except using the preferred materials was formulated and tested for emulsion stability under different conditions, that is, one week at 80 F. and two weeks at 140 F. The results are shown in the following Table VI.

Table VI EMULSION STABILITY TESTS USING MCSR OIL Composition Weight Percent Active Ingredients I Blend Number 12 15 16 17 18 19 20 21 22 23 24 25 Sod. etrol. Sillf 1 49 1. 40 1. 58 1. 58 1. 49 1. 77 2.00 2. 08 1. 95 2. 00 2.12 2. 32 Ca DB Sulf 0.70 77 63 74 81 .77 27 .22 32 .32 .32 Zn Dialkyl dithiophosphate-. 0. 53 53 53 53 53 53 53 53 53 53 53 53 Blend of Neutral Oils 57. 28 57. 30 57.26 57.15 57.17 56. 93 57. 20 57.17 57.20 57.15 57.00 56. Water 40. 00 40. 00 40. 00 40. 00 40. 00 40. 00 40. 00 40. 00 00 40. 00 40. 00 40. 00 Emulsion Stability, One week at 80 F- Ex. Ex. Fail B. Fail Emulsion Stability, Two weeks at 140 F.-. B. Fail B. B. 13. Fail Composition, Weight Percent Active Ingredients Blend Number- 26 27 28 29 13 30 31 32 33 34 35 36 Sod. Petrol Suli 2. 24 2. 25 1. 88 1. 91 1. 93 1. 82 1. 71 1. 1. 57 1. 49 1. 34 1.38 Ca DB Sulf .37 .36 .32 .37 .38 .46 .54 .62 .75 .70 .65 .78 Zn Dlalkyl dithiophosphate 53 53 53 53 53 53 53 53 53 53 Blend of Neutral Oils 56.86 56. 86 57. 27 57.19 57.16 57. 19 57.22 57.25 57. 15 57.28 57.48 57.31 Water 40. 00 40. 00 40. 00 40. 00 40. 00 40. 00 40. 00 40. 00 40. 00 40. 00 40. 00 40. 00 Emulsion Stability, One week at 80 I- Emulsion Stability, Two weeks at 140 F-. B. Fail Ex. Ex. Ex. Ex. B. B. Fail Fail Fail Fail Ex. Excellent. B. =Bordcrline. Fail=Failure.

those outside the essential limits, satisfactorily passed the Vickers pump test. However, some of the emulsions prepared therefrom were not sufliciently stable for extended periods of time to meet the industry requirements of suflicient stability to be marketed in emulsion form or to Withstand periods of storage or shutdown of the hydraulic machinery using the emulsions. I have found that both the type of mineral lubricating oil and the Water used in preparing these emulsions has a decided influence on the emulsion stability. It must be kept in mind that many of the emulsions hereinafter evaluated as unacceptable are nevertheless useful since they still meet the critical Vickers pump test and the many other critical requirements for a fire-resistant hydraulic fluid.

contain 10% and 20% ISWT oil.

All of the compositions shown in Table VI are on an active ingredient basis. The blands of neutral oils used in FRHF Blends Nos. 12, 15 and 19 are the same as pre- 65 viously used, that is, 66.73% of /100 finished neutral,

7 5 comes borderline or unacceptable.

In order to further demonstrate the effects of variations of the concentrations of the active ingredients on the I emulsion stability, a series of extensive emulsion stability tests were conducted up to 60 days time, using both Accordingly, the compositions of this invention are defined as fire-resistant hydraulic fluids, characterized by meeting the tests herein enumerated, containing, in concentrate form, a major portion of a mineral lubricating distilled water and demineralized water. The results for oil, preferably of the MCSR variety, between about 1.55 the former are shown in Table VII. to 3.72 weight percent of an alkali metal petroleum sul- Table VII EMULSION STABILITY TESTS Composition By Weight Percent Active Ingredients Blend Number 37 38 39 40 41 42 43 44 45 46 47 Sod. Petrol. Sulf 1.81 1. 49 1. 43 1. 35 1. 32 1. 28 1. 25 1. 21 1. 17 1.12 1. 36 Ca. 13.13. Sulf .39 .70 -.76 ....81.. -87 .91 .94 .98 1. 02 1.17 .93 Zn Dialkyl dithiophosphate .57 .57 .57 .57 .57 .57 .57 .57 .57 .57 .57 MCSR on 57. 23 57.24 57. 24 57.27 57.24 57.24 57.24 57. 24 57.24 57.14 57.14 40. 00 40. c0 40. 00 40. 00 40.00 40. 00 40. 00 40. 00 40. 00 40. 00 40. 00

Ex. Ex. Bx. Ex. Ex. Ex. Ex. Ex. Ex.

Ace. Ace. Ace. Ex. Ex. Ex. Ex. Ex. Ex.

1 B. Ace 400. Ex. Ex. Ex. 'Ace. Ace. Aec.

. Ex. 1 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex.

Ace. Ace. Ace. Ace. Ex. Ex. Ex. Ex.. Ex.

B. B. B. Ace. Ace. Ace. B. Fail B.

Ace. Ace. Ex. Ex. Ex. Ex. i Ex. Ex. Ex.

B. B. Aceo Ace. Ex. Ex. Ace. B. B.

B. B. Ace. Ace. B. B. Fail Fail Fail *Distilled mo: Ex.= ei cellent. Acc.=aeceptable. B=horderline. Fail=failure.

likely to be stored longer than 60 days at temperatures a-bove 100 F. or below 32 F., in the main, compositrons 3710 46.. meet the general emulsion stability requirements, and such compositions represent additional eka'mplescoming within this invention. The import 'of' the data in Table VII is mainly to point up the effect of slight changes in sulfonate ratios as regards the attainment of long-term storage stability. In every instance, even with the emulsions which fail on agitation or use, the emulsion is restored and is suitable,for use. Blend No. 47 was prepared at the same sodium sulfonate to calcium sulfonate ratio (on an active ingredient basis) as Blend N0. 12, but with a greater quantity of each sulfonate. The stability data on these two blends is identical, but the viscosity of Blend 47 is higher than practical for the invented purpose. An identical series of blends to those reported in Table VII was prepared, using demineralized water, and the stability data for the emulsions therefrom was identical to that shown in Table VII. The use of tap water produces compositions exhibiting reduced levels of emulsion stability, although, as in the case of the demineralized water, the emulsions pass all of the other tests for a fire-resistant hydraulic fluid. Accordingly, Blends Nos. 12-46 all represent examples of compositions coming within the scope of this. invention.

The ingredients used in the compositions of this invention are available commercially and well known in the art.

fonate, about 0.45 to 2.03 weight percent of an alkaline earth metal alkaryl sulfonite, and about 0.47 to 1.43 weight percent of a metal dialkyl dithiophosphate. The foregoing concentrates are blended with about 33% to 42% of water. Other ingredients may be incorporated in the compositions of this invention without departing from the spirit thereof. The principal ingredients are hereinafter more fully defined and illustrated.

The alkali metal petroleum sulfonates are oil-soluble alkali metal salts of mahogany sulfonates formed from the treatment of petroleum distillates, preferably from Pennsylvania grade oil or naphthenic-base crude, with fuming sulfuric acid, sulfur trioxide, or sulfur trioxide complexes, followed by separation of the green sulfonie acid sludge and neutralization of the acid-treated oil with the appropriate alkali metal base or oxide. The mahogany sulfona-tes can be extracted from the unreacted oil by treatment with an organic solvent, such as an aqueous alcoholic solution. Upon distillation of the alcoholic solution,'as described in U.S. Patent 2,125,305, the alkali metal mahogany sulfonate is recovered. These detergent materials are commonly described as alkali metal petroleum sulfonates, or alkali metal mahogany sulfonates derived from a naphthenicor paraffin-base crude. They have average molecular weights of about 500 to 550, preferably of about 500 to 530.

Examples are sodium mahogany sulfonate, potassium mahogany sulfonate, lithium mahogany sulfonate, cesium mahogany sulfonate, rubidium mahogany sulfonate, and mixtures thereof, having an average molecular weight of about 500 to 550 and derived from naphthenic or Pennsylvania paraffinic crudes. Sodium and potassium petroleum sulfonates are preferred.

The analysis of a typical alkali metal petroleum sulfonate, such as was used in Blend No. 12 and identified as sodium petroleum sulfonate (Sherosope T), a proprietary product of the Bryton Chemical Company, is shown in Table VIII.

Table VIII Controlling Min. Max.

Method 1 Typical Analysis Sodium Sulionates (wt percent) 59. 8 Mineral Oil (wt. percent) 34. 4 Inorganic Salts (wt. percent) 0. 4 Water (wt. percent) 3. 5 Free NaOH (wt. percent) 0. 01 Sodium Carboxylate (wt. percent) 2. 5 Average Molecular Wt 513 Specific Gravity, (SO/60 F. 1. 0313 API Gravity 5. 7 Sulfated Ash (wt percent) 9. 2 Acid umber 0. 03 Base Number 0.93 Viscosity at 210 F. (S.U.S.) 2, 934 Pour Point F.) +70 Weight per gallon (lbs.) 8. 590

Inorganic Salts Sodium Carbonate...

1 Determined by ASTM method as indicated. 2 Wide range. The oil-soluble alkaline earth metal alkaryl sulfonates, which are balanced with the alkali metal petroleum sulfonate in accordance with this invention, have the general formula,

[( )n SOs-12M where (R) is one or more alkyl, alkaryl or aralkyl groups, n having a value of 1 to 5 or more, and the aromatic nucleus may be a single or condensed ring, or a partially hydrogenated ring. R will generally and preferably contain 10 to 14 carbon atoms, and where two R groups are present, the total number of carbon atoms in these substituent groups is from 17 to 36 per sulfonic acid molecule. The average molecular weight of the alkaline earth metal alkaryl sulfonates used herein may be from about 40 925 to 975 and preferably is about 940 to 970. In this connection, one particular alkaline earth metal alkaryl sulfonate tested, having an average molecular weight of 890, was unsuitable. The preferred alkaline earth metal Examples of other alkaline earth alkaryl sulfonates are:

Strontium undecylnaphthalene sulfonate Calcium undecylbenzene sulfonate Calcium dodecylbenzene sulfonate Barium dodecylbenzene sulfonate 30 Strontium dodecylbenzene sulfonate The analysis of a typical alkaline earth metal sulfonate, such as was used in Blend No. 12 and identified as calcium dodecylbenzene sulfonate (Bryton Calcium Sulfonate a proprietary product of the Bryton Chemical Company, is shown in Table IX.

Table IX REPRESENTATIVE CALCIUM DODECYL BENZENE SULFONAIE ASSAY Controlling Method 1 Typical Properties Min. Max

Calcium sulionates (wt. percent)" 43. 8 (D 1216) 45.0 Mineral Oil (wt. percent) 53. 0

Water (wt. percent) r. 1.0

Inorganic Salts (wt. percent) 0.9

Basieity as 03(0H); (wt percent). 1. 6

Calcium Carboxylate (wt percent). 0. 1

Average Molecular Wt r. 944

Specific Gravity, ./60 F 0. 9554 API Gravity 16. 6

Sultated Ash (w 10. 2

Base Number 24. 6

Viscosity at 210 F (S U S 160.1

Pour Point F. +5

Weight per gallon (lbs.) 7. 957

1 Determined by ASTM method as indicated. 2 Close range.

alkaryl sulfonates are calcium and barium dodecylbenzene sulfonates and their mixtures.

Methods of preparing and purifying these alkaline earth metal sulfonates are described in the prior art, e.g., United States Patents 2,760,970, Le Seur: 2,763,615, Faust; 2,839,470, Warren et al.; 2,856,361, Schlicht; 2,861,951, Carlyle; 2,880,173, Honeycutt; 2,883,340, Wasley et al.; 2,902,448, Collins; 2,943,052, Carlyle et al.; and 2,947,694, Cragson.

The heavy-metal salt of an alkyl dithiophosphate used in accordance with this invention is preferably a zinc or cadmium salt of a dialkyl dithiophosphate of the formula:

wherein R is an alkyl radical having from 4 to 10 carbon atoms, and M is zinc or cadmium. Although other tech- -'17 niques are available, in general these substances are prepared by reacting the corresponding aliphatic alcohol with phosphorus pentasulfide to form the esters. The resulting esters are acidic and readily form salts with bases of the metal M, i.e., with the oxides, hydroxides, sulfides, or carbonates. The R-group may be straight-chain, branchedchain, or cycloaliphatic in structure. The metal salts falling within the definition are oil-soluble and are stable components in the concentrates or dilute emulsions. It is preferred that R have 6 to 8 carbon atoms. Examples include Zinc dihexyl dithiophosphate Zinc dioctyl dithiophosphate Zinc dinonyl dithiophosphate Zinc dibutyl dithiophosphate 18 Zinc di-t-butyl dithiophosphate Zinc di-pentyl dithiophosphate Cadmium dibutyl dithiophosphate Cadmium dihexyl dithiophosphate Cadmium dicyclohexyl dithiophosphate Cadmium didecyl dithiophosphate The following Table X gives the chemical and physical characteristics of a typical zinc dialkyl dithiophosphate (namely the proprietary compound identified as Oronite OLOA 262), such as was used in the preferred blend, No. 12. This product has alkyl groups of 6 to 8 carbon atoms, identifiedas hexyl, heptyl, and octyl groups.

Table XI gives the chemical and physical characteristics of the mineral lubricating oils used in the preferred compositions of this invention, and in other blends that have been prepared and tested.

*Determined by ASTM method as indicated.

Table XI CHEMICAL AND PHYSICAL CHARACTERISTICS OF MINERAL LUB RICAIIN G OILS Characteristics (ASTM Methods) Oil Identification No. H

API Sp. Gr., Flash, Fire, Via/100 F., Gravity, 60/60 1?. F. F. SUS

degs.

1. 80/100 MCSR Neutral 35. 9 0. 8453 79. 7 2. 170/100 MSOR NeutraL. 81. 3 0. 8692 172.3 3. 100 Pale Oil 22. 4 0. 9189 102 4. 100 Neutral (L). 22. 5 0. 9188 105 5. B-P-Neutral 22.3 0.9195 109 6. B-P-Neutia 22. 2 0.9201 113. 5 7. 100 Pale Oil 21. 7 0. 9236 103. 1 8. 100 Pale O 22. 2 0.9206 104. 8 9. 100 Pale O 22.4 0.9194 99,7 10. 100 Pale O 22.1 0.9212 104.5 11. 100 Pale 011 22.7 0.9176 103.8 12. 100 Pale O11 21.8 0.9230 102. 9 13. 100 Pale Oil 21. 8 0. 9230 102. 5 14. 80/100 MCSR Neut. and 10% ISWT 35.6 0. 8458 81.2 15. 170/100 MCSR Neut. and ISWT 31. 4 0. 8686 175. 7

Characteristics (ASTM Methods) Oil Identification No. Interfacial Vial ,Vis.l Pour Acid No. Tension at 130 F. 210 F. V.I. Pt., F. (1948) 88 F. oil (SUS) (S US) against water (dynes cm.)

1. 80.100 MCSR Neutral 56.0 37. 5 99 -=10 0. 03 2. 170/100 MCSR Neutral. 93. 2 44. 7 99 0 0.05 3. 100 PaleOil 62.9 38. 1 23 60 0.03 4. 100 Neutral (L) 64. 2 38. 2 39 40 0. 03 5. B-P-Neutral. 38 18 -'45 6. B-P-Neutral 66.6 38.8 14 0.03 7. 100 Pale Oil 61. 3 38.1 18 0. 03 35. 5 8. 100 Pale 011.. 38. 3 22 55 0. 03 38. 4 9. 100 Pale Oi1 38.1 28 55 0. 03 37. 7 10. 100 Pale Oil 38. 3 19 50 0. 03 38. 4 11. 100 Pale Oil 38. 2 19 50 0. 03 40. 3 12. 100 Pale Oil. 38. 2 21 55 0. 03 40. 1 13. 100 Pale Oil 38.1 21 -55 0. 03 41.3 14. /100 MCSR Neut. and 10% ISW'I.. 56. 7 37. 8 103 0 0. 03 35. 3 15. 170/100 MCSR Neut. and 20% ISWT .94. 9 45. 0 0 0. 03 43. 3

The aniline points of the lubricating oils shown in Table XI vary from about 140 to 150 F., and the oils may contain from about 1.5 to 2.5 Wt. percent sulfur. Oils Nos. 3, and 7-13 are products of the Macmillan Oil Company, oil No. 4 is a product of the Lion Oil Company, and oils Nos. 5 and 6 are products of the Berry Asphalt Company.

To illustrate the method of preparation of the FRHF compositions of this invention, the following example is given:

About 165 lbs. of calcium petroleum sulfonate is preheated to about 100 F. to facilitate handling, and 4,405 pounds of neutral oil are charged to a clean mixing kettle, agitated and heated to about 150 F. Forty-eight pounds of zinc dialkyl dithiophosphate are added to the heated oil, agitation is continued, and the temperature maintained at 140 to 150 F. The warm calcium petroleum sulfonate is added, and agitation continued with the temperature maintained at 135 to 145 F.; then 165 pounds of sodium petroleum sulfonate are added to the mixture, and agitation is continued for about one hour after the last addition, with the temperature held at 130 to 140 F. Stirring is continued for about one hour, and the temperature is maintained above about 120 F. At this point, samples may be taken for analysis as to base No. (ASTM D-664), which should be within the range of about 0.7 to 1.7, acid No. (ASTM D-974), which should be about 1.00 to 1.4, and sulfated ash (ASTM D-874), which should be in the range of about 0.66 to 0.80. Also, an emulsion can be prepared by mixing 120 grams of concentrate at above about 120 F. with 80 grams of distilled water, with water at room temperature. Acceptable emulsifying properties are evidenced at this point by emulsification with less than 10 minutes of mixing.

Following these analyses and the preparation of stable samples, all of the water, i.e., 3,186 lbs. deionized water or distilled water, is added as rapidly as possible without agitation during the addition of water. At this time, the temperature of the mixture should not be less than 90 F., and not greater than 130 F. The emulsion is then mixed for about 2 hours and cooled as much as possible. The water content (ASTM D-95) in this example is about 37.5 to 39.0% by volume, and the emulsion is stable after one hour at 150 to 160 F.

The following Table XII gives the physical properties of a concentrate containing 3.45% (2.14% by wt. on active ingredient basis) of sodium petroleum sulfonate (Sherosope T or Petronate CR), 3.36% (1.51% by weight on active ingredient basis) of calcium dodecylbenzene sulfonate (Bryton Calcium Sulfonate 45), 1.00% zinc dialkyl dithiophosphate (Oronite 262 or Lubrizol 609), and 92.19% neutral oil, which may be Macmillan 100 pale oil, Lion 100 neutral, or Berry Permaseal neutral, and also the properties of the emulsion prepared therefrom.

Table XII CONCENTRATE (BLEND NO. 37)

Property Vis. at 100 F. (SUS) Vis. at 210 F. (SUS) H2O Content, wt. percent API gravity Sp. Gr. at 60l60 F. Flash Point Fire Point F.) Aniline Point F.) Pour Point F.) sulfated Ash (wt. percen Base No. (ASTM D-664) (Ks'ilii 13251311:

l a (dynes/em.)

FIRE-RESISTANT HYDRAULIC-FLUID W/O EMULSION By Weight By Volume 61.75% (Blend N0. 37). 38.25% Distilled or deionized water.

Apparent Viscosity at F. (before use). 423 SUS. Apparent Viscosity at F. (before use). 217 SUS. Sp. Gr. at 60/60 F 0.9507. API Gravity 16.4". Weight per gallon 7.967 lbs.

The embodiments of this invention in which an exclusive property or privilege is claimed are defined as follows.

1. A hydraulic-fluid concentrate consisting essentially of a major portion of a neutral mineral lubricating oil and the following ingredients:

Ingredient- Weight percent Alkali metal petroleum sulfonate (mol.

Wt. about 500-550) 1.55 to 3.72

wherein the ratio of concentration of alkali metal petroleum sulfonate to alkaline earth metal sulfonate is about 0.71 to 8.26, and the total amount of said sulfonates is greater than about 2.77 weight percent and less than about 4.73 weight percent.

2. A hydraulic-fluid concentrate in accordance with claim 1 in which said alkali metal petroleum sulfonate is sodium petroleum sulfonate.

3. A hydraulic-fluid concentrate in accordance with claim 1 in which said alkaline earth metal alkylaryl sulfonate is calcium dodecylbenzene sulfonate.

4. A hydraulic-fluid concentrate in accordance with claim 1 in which the total amount of said sulfonates is about 3.50 to 3.80 weight percent.

5. A hydraulic-fluid concentrate in accordance with claim 4 in which the total amount of said sulfonates is about 3.65 weight percent.

6. A hydraulic-fluid concentrate consisting essentially of a major portion of a neutral mineral lubricating oil and the following ingredients:

Ingredient- Weight percent Alkali Metal petroleum sulfonate (mol.

wt. about 500-550) 2.14 to 3.22

7. A hydraulic-fluid concentrate in accordance with claim 6 in which said alkali metal petroleum sulfonate is sodium petroleum sulfonate.

8. A hydraulic-fluid concentrate in accordance with claim 6 in which said alkaline earth metal alkylaryl sulfonate is calcium dodecylbenzene sulfonate.

9. A hydraulic-fluid concentrate in accordance with claim 6 in which the total amount of said sulfonates is about 3.50 to 3.80 weight percent.

10. A hydraulic-fluid concentrate in accordance with claim 6 in which the total amount of said sulfonate is about 3.65 weight percent.

11. A hydraulic-fluid concentrate consisting essentially of a major portion of a neutral mineral lubricating oil, about 2.48% by weight of sodium petroleum sulfonate, about 1.17% by weight of calcium dodecylbenzene sulfonate, and about 0.88% by weight of zinc dialkyl dithiophosphate in which the alkyl groups contain 6 to 8 carbon atoms.

12. A hydraulic-fluid concentrate consisting essentially of a major portion of a neutral mineral lubricating oil, about 1.93% by weight of sodium petroleum sulfonate, about 0.38% by weight of calcium dodecylbenzene sulfonate, and about 0.53% by weight of zinc dialkyl dithiophosphate in which the alkyl groups contain 6 to 8 carbon atoms.

13. A hydraulic-fluid concentrate consisting essentially of a major portion of a neutral mineral lubricating oil, about 2.14% by weight of sodium petroleum sulfonate, about 1.51% by weight of calcium dodecylbenzene sulfonate, and about 0.95% by Weight of zinc dialkyl dithiophosphate in which the alkyl groups contain 6 to 8 carbon atoms.

14. The method of preparing a hydraulic-fluid concentrate which consists in mixing a neutral mineral lubricating oil with a metal di-C to C alkyl dithiophosphate wherein the metal is of the group consisting of zinc and cadmium at a temperature of about 140 to 150 F., adding an alkali metal petroleum sulfonate having a molecular weight of about 500 to 550 to the mixture while same is maintained at said temperature, adding an alkaline earth metal alkylaryl sulfonate having an average molecular weight of about 925 to 975 and containing 10 to 14 carbon atoms in the alkyl portion and said aryl portion being a member of the group consisting of phenylene and naphthylene to said mixture at a temperature of about 130 to 140 F., stirring said mixture for about one hour at a temperature of about 120 F., and allowing said mixture to cool.

15. A fire-resistant hydraulic fluid consisting essentially of an emulsion of about 33 to 45 by weight of a water phase and about 67 to 55% by weight of an oil phase which consists in a major portion of a neutral mineral lubricating oil and the following ingredients:

Ingredient- Weight percent Alkali Metal petroleum sulfonate (mol.

wt. about 500-550) 1.55 to 3.72

16. A fire-resistant hydraulic fluid consisting essentially of an emulsion of about 33 to 45% by weight of a water phase and about 67 to 55 by weight of an oil phase which consists in a major portion of a neutral mineral lubricating oil and the following ingredients:

Ingredient- Weight percent Alkali metal petroleum sulfonate (mol wt. about 500-550) 2.14 to 3.22 Alkaline earth metal alkylaryl sulfonate (av. mol. wt. about 925-975) containing 10 to 14 carbon atoms in the alkyl portion and said aryl portion being a member of the group consisting of phenylene and naphthylene 0.63 to 1.51 Metal di-C C alkyl dithiophosphate wherein the metal is of the group consisting of zinc and cadmium 0.88 to 0.95

17. A fire-resistant hydraulic fluid consisting essentially of an emulsion of about 33 to 45 by weight of a Water phase and about 67 to 55% by Weight of an oil phase which consists in a major portion of a neutral mineral lubricating oil, about 2.48% by weight of sodium petroleum sulfonate, about 1.17% by weight of calcium dodecylbenzene sulfonate, and about 0.88% by Weight of zinc dialkyl dithiophosphate in which the alkyl groups contain 6 to 8 carbon atoms.

18. A fire-resistant hydraulic fluid consisting essentially of an emulsion of about 33 to 45 by weight of a water phase and about 67 to 55% by weight of an oil phase which consists in a major portion of a neutral mineral lubricating oil, about 1.93% by weight of sodium petroleum sulfonate, about 0.38% by weight of calcium dodecylbenzene sulfonate, and about 0.53% by weight of zinc dialkyl dithiophosphate in which the alkyl groups contain 6 to 8 carbon atoms.

19. A fire-resistant hydraulic fluid consisting essentially of an emulsion of about 33 to 45% by weight of a water phase and about 67 to 55 by weight of an oil phase which consists in a major portion of a neutral mineral lubricating oil, about 2.14% by Weight of sodium petroleum sulfonate, about 1.51% by weight of calcium dodecylbenzene sulfonate, and about 0.95% by Weight of zinc dialkyl dithiophosphate in which the alkyl groups contain 6 to 8 carbon atoms.

References Cited by the Examiner UNITED STATES PATENTS 2,913,411 11/1959 Schiermeier 25249.5 2,961,404 11/1960 Francis 252 JULIUS GREENWALD, Primary Examiner.

ALBERT T. MEYERS, Examiner.

Claims

1. A HYDRAULIC-FLUID CONCENTRATE CONSISTING ESSENTIALLY OF MAJOR PORTION OF A NEUTRAL MINERAL LUBRICATING OIL AND THE FOLLOWING INGREDIENTS:

15. A FIRE-RESITANT HYDRAULIC FLUID CONSISTING ESSENTIALLY OF AN EMULSION OF ABOUT 33 TO 45% BY WEIGHT OF A WATER PHASE AND ABOUT 67 TO 55% BY WEIGHT OF AN OIL PHASE WHICH CONSISTS IN A MAJOR PORTION OF A NEUTRAL MINERAL LUBRICATING OIL AND THE FOLLOWING INGREDIENTS: