Griffith III, John Q. (Claymont, DE)
Williams, Edward S. (Claymont, DE)
Reiland Jr., William H. (West Chester, PA)

05/178479

06/11/1974

09/07/1971

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Sun Oil Company of Pennsylvania (Philadelphia, PA)

252/72

508/378, 508/374, 252/73, 252/75, 252/74, 252/76

C10M169/00; C09K3/00

252/72-76,35,41 208/14,18

3242068	Production of lubricating oil	March 1966	Paterson
3284340	Method for producing lubricating oils	November 1966	Halik et al.
3383312	Stable, fluid, soap thickened oil lubricant compositions	May 1968	Coppock
3498920	COMPOSITIONS OF LIQUID PARAFFINS CONTAINING MIXTURES OF ALKYL-SUBSTITUTED POLYNUCLEAR AROMATIC HYDROCARBONS AS SWELLING AGENTS	March 1970	Nichols et al.
3533952	TRANSMISSION OF MECHANICAL POWER	October 1970	Pruitt et al.
3544472	POWER TRANSMISSION HYDROCARBON OIL	December 1970	Bray et al.
3663427		May 1972	Thomas et al.
3682813		August 1972	Dun et al.
3684684		August 1972	Coleman et al.
3694363		September 1972	Griffith et al.

Georgi: "Motor Oils and Engine Lubrication," (1950), pub. by Reinhold Pub. Co., pp. 108, 153, 154..

Rosdol, Leon D.

Pitlick, Harris A.

Church, Esq. Esq. Esq. Hess Bisson G. L. J. E. B. A.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of our application Ser. No. 34,899, filed May 5, 1970, now U.S. Pat. No. 3,694,363 issued Sept. 26, 1972.

The invention claimed is

1. A soap thickened antileak hydraulic oil comprising an effective amount for thickening of a lithium soap of a fatty acid having 12-22 carbon atoms or an aluminum soap of said acid, and a hydrocarbon base oil having a viscosity in the range of 80-3000 SUS at 100°F said base oil consisting essentially of a blend of at least one hydrorefined naphthenic oil and at least one hydrocracked paraffinic oil, each said oil having a viscosity in the range of 40-12,000 SUS at 100°F.

2. Hydraulic oil according to claim 1 and wherein said hydrorefined naphthenic oil contains less than 80 ppm of basic nitrogen and has a viscosity-gravity constant in the range of 0.840-0.899.

3. Hydraulic oil according to claim 1 and wherein said soap is lithium stearate.

4. Hydraulic oil according to claim 1 and containing in addition a zinc dialkyl dithiophosphate antiwear agent.

5. Hydraulic oil according to claim 4 and wherein said hydraulic oil contains in the range of 0.1-1% lithium stearate, in the range of 0.02-2% neutral barium petroleum sulfonate and in the range of 0.1-5% zinc dialkyl dithiophosphate.

6. Hydraulic oil according to claim 3 and containing in the range of 0.3-2% zinc dialkyl dithiophosphate antiwear agent.

7. Hydraulic oil according to claim 1 and wherein said base oil has a viscosity at 100°F. in the range of 150-350 SUS.

8. Hydraulic oil according to claim 7 and containing in the range of 0.1-1% lithium stearate.

9. Hydraulic oil according to claim 1 wherein said base oil consists of a blend of at least one hydrorefined naphthenic oil and at least one hydrocracked paraffinic oil.

10. Hydraulic oil according to claim 1 wherein said base oil contains less than 80 ppm of basic nitrogen.

11. Hydraulic oil according to claim 1 wherein said base oil has an aniline point in the range of 150°-170°F.

12. Hydraulic oil according to claim 1 and having an aniline point in the range of 195°-215°F. said hydraulic oil being suitable for use in contact with a silicone rubber.

13. Hydraulic oil according to claim 1 and having an aniline point of about 200°F.

14. Hydraulic oil according to claim 1 and wherein said soap is selected from stearates, palmitates, tallates, laurates, oleates and mixtures thereof.

15. Hydraulic oil according to claim 1 wherein said oil contains in addition a member selected from low nitrogen content paraffinic distillate, low nitrogen content paraffinic solvent raffinate oil, hydrorefined paraffinic distillate, hydrorefined paraffinic raffinate, polycyclic aromatic concentrate, unhydrorefined naphthenic distillate, and naphthenic acid-free naphthenic distillate.

16. A polymer thickened antileak hydraulic oil comprising a polybutene having a molecular weight higher than several hundred thousand in amount effective to thicken the oil and a base oil consisting essentially of a blend of hydrorefined naphthenic oil and hydrocracked paraffinic oil.

17. A soap thickened antileak hydraulic oil comprising an effective amount, for thickening, of a lithium soap of a fatty acid having 12-22 carbon atoms or of an aluminum soap of said acid, and a hydrocarbon base oil having a viscosity in the range of 80-3000 SUS at 100°F., said base oil consisting essentially of a hydrorefined naphthenic oil or a blend of two or more hydrorefined naphthenic oils having a viscosity in the range of 40-12,000 SUS at 100°F., at least one said hydrorefined naphthenic oil containing less than 80 ppm of basic nitrogen and having a viscosity-gravity constant in the range of 0.840-0.899.

18. Hydraulic oil according to claim 17 wherein said base oil is a blend of at least two hydrorefined naphthenic oils.

The following patents and applications, all assigned to The Sun Oil Company (as is the present application), are related to the disclosure of the present application in that they disclose methods of obtaining aromatic extracts or concentrates, distillate oils, hydrocracked oils and hydrorefined oils, which can be used to make the hydraulic oil composition of the present invention.

The disclosure of all of the following applications and patents is hereby incorporated in the present application:

U.S. Pat. No. 3,462,358 issued 8-19-69, U.S. Pat. No. 3,681,279 issued 8-1-72, U.S. Pat. No. 3,502,567 issued 3-24-70, Ser. No. 730,999 filed 5-22-68, U.S. Pat. No. 3,619,414 issued 11-9-71, Ser. Nos. 850,716 and 850,717 both filed 8-18-69 (both now abandoned), U.S. Pat. No. 3,654,127 issued 4-4-72, Ser. No. issued 8-1-72, Ser. No. 35,231 filed 5-6-70, Ser. No. 60,642 filed 8-2-70 (now abandoned), U.S. Pat. No. 3,715,302 issued 2-6-73, U.S. Pat. No. 3,732,154, issued 5-8-73, U.S. Pat. No. 3,663,427 issued 5-16-72, U.S. Pat. No. 3,666,657 issued 5-30-72, Ser. No. 140,398 filed 5-5-71 and U.S. Pat. No. 3,759,817 issued 9-18-73.

U.S. Pat. No. 3,383,312 to Walter J. Coppock is also pertinent since it describes a method of preparing a fluid soap thickened mineral oil lubricant composition, which method can be useful in practice of the present invention.

BACKGROUND OF THE INVENTION

The industrial oil market is continuing to grow at a rapid pace. Accompanying this growth is the demand for better lubricant properties. Specific improvements are needed to cope with trends towards more severe operating conditions and better pollution control. In the response to these requirements, research has made important advances in upgrading antiwear and antileak properties. Wear-resistant oils can alleviate the equipment problems and failures caused by increased pressures and temperatures, shock loading, reduced tolerances, etc. Antileak oils can decrease the undesirable loss of lubricants. Not only do these latter oils reduce consumption, but they held curb the pollution of our natural waters. These problems are considered in greater detail in our patent U.S. Pat. No. 3,694,363, issued 9-26-72.

SUMMARY OF THE INVENTION

An improved antileak hydraulic oil of the gel-thickened type comprises an effective amount of a lithium soap (e.g., 0.1-1% Li stearate) or an aluminum soap (e.g., 0.5-2% Al stearate), or mixtures of such soaps, and a base oil having a viscosity in the range of 70-3000 SUS at 100°F., said base oil comprising at least one hydrorefined naphthenic oil or a hydrocracked oil having a viscosity in the range of 40-12,000 SUS at 100°F. The hydraulic oil can also contain one or more of the following: an antirust agent (e.g., 0.02-2% typically 0.2% barium petroleum sulfonate), an antioxidant (e.g., 0.05-1% of an amine type), an antifoam (e.g., 0.05-1% of a silicone type) and an antiwear (e.g., 0.1-5%, typically 0.3-2%, zinc dialkyl dithiophopshate, such as zinc-isopropyl, decyldithiophosphate) or tricresylphosphate. For systems having seals comprising synthetic rubbers (e.g., "Buna N", GRS, ABS) it is preferred that the aniline point of the base oil be in the range of 150°-170°F. For systems where the seals are of other rubbers or materials, a higher aniline point may be required (e.g., for the silicone rubbers an aniline point of about 200°F. imparts the proper seal-swelling character to the hydraulic oil). In calculation of the aniline point of the base oil, one must consider the contribution of aromatic additives (e.g., those marketed as seal swell agents) and the hydrocarbon diluent used in many commercial additives. The term "base oil" in the present application refers to the total hydrocarbons of the 40-12,000 SUS viscosity range which are present in the final hydraulic oil, it being understood that some of these hydrocarbons can be contributed via the usual commercial additives.

A preferred antioxidant is DBPC (ditertiarybutyl paracresol) or an amine type, used in combination with sufficient zinc dialkyl dithiophosphate to impart antiwear properties (e.g., 0.010-020% Zn).

The hydraulic oil can show good antiwear and antileak performance and good hydrolytic and oxidation stability in the ASTM D-943 turbine oil stability test (TOST).

The base oils preferably contain less than 80 ppm of basic nitrogen and can be those described in the previously cited applications of Mills et al. and, more preferably, are blends of two or more hydrorefined naphthenic oils (e.g., a blend of a 100 SUS at 100°F. hydrorefined naphthenic oil and a 2500 SUS at 100°F. hydrorefined naphthenic oil) or a blend of hydrorefined naphthenic oil and hydrocracked paraffinic oil.

In the hydraulic oil of the present invention, leakage reduction is achieved by designing into the lubricant the ability to maintain good rubber seal condition (e.g., by proper choice of aniline point of the base oil) and the ability to obstruct small leaks with retardant materials (e.g., Li or Al coaps or polymers). Plant trials have been conducted comparing the performance of the antileak hydraulic oils of the present invention to current, standard products. Lubricant loss was lowered as much as 88% by the leak resistant formulations. These antileak hydraulic oils of the present invention also have good overall properties and have performed well in many types of plant equipment.

FURTHER DESCRIPTION

The hydrocarbon base oil can also contain a low nitrogen content paraffinic distillate or solvent raffinate oil, a hydrorefined paraffinic distillate or raffinate, a viscosity index improver (e.g., high molecular weight polybutene or a polyacrylate or polymethylacrylate, preferably the dispersant type), a polycyclic aromatic concentrate (such as cycle stock) or extract (such as a furfural extract from a naphthenic distillate) to adjust the 335 UVA of the base stock (which preferably is in the range of 0.01-0.4, more preferred 0.02-0.2) and/or the aniline point and an unhydrorefined naphthenic distillate or a naphthenic acid-free naphthenic distillate (to improve the D-943 test performance).

Paraffinic oils are those having a viscosity-gravity constant (VGC) in the range of 0.790 to 0.819 (preferably above 0.799).

Naphthenic oils have a VGC in the range of 0.820 to 0.899 and the preferred hydrorefined naphthenic oils have a VGC in the range of 0.840 to 0.899. Hydrorefined, relatively aromatic oils, having a VGC in the range of 0.900 to 0.920, can sometimes be used as a whole or partial substitute for the hydrorefined naphthenic lube. Aromatic oils (including hydrorefined or hydroaromaticized oils) having a VGC in the range of 0.921 to 1.050 and greater, can be useful in minor proportions (e.g., 1-20%) for adjusting the aniline point of the base oil, particularly when the base oil contains a high proportion of a high VI hydrocracked paraffinic oil.

As an additional component, or as a partial or complete substitute for the hydrorefined naphthenic oils previously described, hydraulic oils of the gel or polymer thickened types can contain a wax-free, hydrogenated polyolefin oil (e.g., see Canadian Patent 842,290; U.S. Pat. No. 3,598,740) or a high viscosity index, hydrocracked oil or a mixture of such components. In such blends an aromatic oil or concentrate rich in aromatic hydrocarbons (e.g., cycle oil) may have to be added to obtain the proper aniline point for seal swelling.

The preferred polyolefin oils are polymers or copolymers of C ₂ -C ₈ olefin which have a pour point no greater than -35°F., and preferably below -50°F. The hydrogenation can be from 50% to 100% of saturation and, preferably, is to a bromine number no greater than 10, more preferably less than 5. Preferred polyolefins include ethylene-propylene copolymer, polypropylene, polybutene (especially polyisobutylene), and poly(1-octene).

The high VI hydrocracked paraffinic oil component can be obtained by hydrocracking a high viscosity distillate or dewaxed distillate from a paraffinic crude (such as Lagomedio) and typically has a VI in the range of 90-105 and contains in the range of 3-30% of aromatics by clay-gel analysis. The hydrocracked lubes are preferably stabilized (against UV light degradation and sludging) by extraction of the hydrocracked oil with aromatic selective solvents, such as furfural or phenol or by hydrorefining to reduce the 260 UVA at least 30% (preferably 40%).

The preferred "stabilized" hydrocracked oils (whether extracted or hydrorefined) are characterized by having a D-943 test life (to an increase in acid number of 2.0) which is at least 20% lower than the D-943 life of an unstabilized hydrocracked oil but which is at least 20% greater than the D-943 life (with the usual amount of inhibitor) of an unhydrocracked solvent refined lube of the same viscosity.

One process for preparing a high VI hydrocracked oil comprises fractionating the stock material (such as an atmospheric residuum from Lagomedio crude) into three fractions, boiling at (a) from 720°-855°F., (b) 855-980°F. and (c) the residuum or a fraction boiling at from 986°-1070°F., solvent extracting fraction (b) with a solvent having preferential solubility for aromatics such as furfural, recombining the three fractions, dewaxing to 0°F. pour point or lower, and hydrocracking the combined fractions at from 720°-800°F. using a hydrogen partial pressure of from 2,000 to 3,000 psi., and a sulfided nickel-tungsten catalyst supported on silica-alumina and containing a minor amount of a fluoride (e.g., Gulf GC-6). The higher boiling fraction is deasphalted if required.

Examples of such hydrocracked oils are found in U.S. Pat. No. 3,579,435 and in the following commonly-owned applications (the disclosure of which is incorporated herein by reference):

Serial No. Filing Date Inventor(s) ______________________________________ 780,241 11-19-68 Thompson et al. 875,502 11-10-69 Thompson 64,656 8-17-70 Kress ______________________________________

The preferred amount of gelling agent to add to a given base oil can be determined from an experimentally obtained "soap in oil curve." That is, various amounts of soap are added to base oil samples (which can also include some or all of the other additives) and the viscosity of the soap-oil samples is determined. The results are plotted as a viscostiy versus concentration curve. In such a curve, a point will be found where the viscosity suddenly increases greatly. This will be the minimum concentration of soap which should be put into the oil for antileak protection. Generally, about 0.1% more soap than this minimum concentration should be put into the oil. The maximum amount of soap (or other gelling agent) will be where the solution "lumps-up" or becomes non-homogeneous.

The preferred soaps are lithium or aluminum stearate; however, any of the prior art lithium or aluminum soaps which have been used in petroleum lubricants can be useful in hydraulic oils of the present invention. Such soaps are shown, for example, in U.S. Pat. Nos. 2,489,300 and 3,383,312. For soap thickening useful lithium or aluminum soaps include soaps of fatty acids containing in the range of 12-22 carbon atoms, preferably an unsubstituted fatty acid. Stearates, palmitates, tallates, laurates, oleates and mixed soaps are among the useful soaps.

Polymer thickened oils can contain a small amount of a soap as a dispersant for the polymer or as a stabilizer (see U.S. Pat. No. 2,489,300).

To reduce equipment leakage, is important that elastomeric seals and gaskets maintain a slight positive swell and remain pliable. Shrinkage and hardening allow oil to bypass. Certain base oils can help to keep the seals working properly.

A good test for judging if a base stock will properly condition the most commonly used seals, i.e., Buna N and Neoprene, is the aniline point (ASTM D-611). This test measures the solubility temperature of aniline and the lubricant. The aniline point is, therefore, a measure of solvency of the lubricant. Data obtained for the percent swell for Buna N and Neoprene seals for a series of 250 SUS at 100°F. oils having aniline points ranging from 150°F. to 230°F. show, that to obtain a small positive swell with the seals tested, the base oil should have an aniline point between 150°F. and 170°F. Lubricants which are mostly paraffinic in structure have high aniline points and will shrink the rubber and make it hard. This permits the lubricant to leak. On the other hand, if the aniline point is below 150°F., excessive swell often occurs and the seal may be cut and torn by the rubbing surface, thereby allowing lubricant to bypass. This correlation does not necessarily apply to lubricants which contain seal conditioning additives. For other rubbers, such as the silicones, a different aniline point range may be required for proper swelling (e.g., for silicone rubbers an aniline point in the range of 195°-215°F. is preferred).

Note that such prior art as U.S. Pat.No. 2,408,983 (which at column 5 shows an aniline point of 178°F.), U.S. Pat. No. 2,489,300 (which in examples) and 2 shows aniline points of 145°F. and 131°F.) and U.S. Pat. No. 2,616,854 (which shows a range of 175°-190°F.) lead the art away from our preferred ranges of 150°-170°F. and 195°-215°F.

Besides utilizing a base oil which properly conditions the rubber seals and gaskets, leakage can also be reduced by restricting small openings with leak retardant materials. The leak retardant must be carefully selected so that the properties of the lubricant are not harmed. There are two basic types of antileak additives presently being used. The first is the polymeric type which includes material having molecular weights greater than several hundred thousand (e.g. polybutene). The second involves gelling agents (e.g., organic salts of polyvalent metals or "soaps") which can have molecular weights of about three hundred.

It has been postulated that the polymeric materials develop a more rigid structure in areas of low shear rates, such as the threads of a leaky coupling. The viscosity, therefore, increases and flow is hindered from the high pressure zone.

Gelling agents are believed to perform in a different manner. That is, they build up fibers or log jams in small openings, thereby barricading them and preventing fluid flow.

Both of these types of antileak additives shear down temporarily when subjected to pump, valve, etc. operations. Permanent shear loss is also experienced to a limited degree. Because this does occur, the equipment is able to operate satisfactorily without clogging problems.

There are no known products which completely stop leakage. One reason for this is that the types of leak retardants which can be used are limited by other performance characteristics. The antileak component must be a material which will not cause plugging in filters as small as 5 microns or interfere with servovalve operation where clearances are extremely critical. Other properties of the lubricant itself, such as the oxidation stability, foam resistance, etc., must not be sacrificed.

In the following examples, as in the rest of this application, all percentages are by weight.

ILLUSTRATIVE EXAMPLES

The best way to evaluate new formulations is in the actual machinery in which leak problems are encountered. There is presently no standard way to measure antileak properties in the laboratory. A laboratory method has been devised, however, which appears to correlate with field experience. This test has been useful in measuring good versus bad antileak oils or improvements over a given reference oil. The reference oil can be, for example, a rust and oxidation (R&O) inhibited paraffinic hydraulic oil. This R&O reference contains all of the necessary additives to guarantee good lubricant performance but incorporates no leak retardants.

The apparatus in which leakage characteristics are measured is a U-shaped combination of 3/4" iron nipples, union sleeves, and elbows. They are joined together by hand tightening in a U-shape and then spot welded to hold in a fixed position. One end of the U is capped, the other end is connected to a pressure source. The proceedure utilizes a 300 cc oil sample. The system is pressurized to 30 psi. with nitrogen and allowed to stand for 1 hour. The oil which has dripped out at the end of this period is collected and weighed.

As with most screening tests, this method can only predict whether the oil is better than another. It cannot indicate the degree of improvement to be provided. Nothing but a large amount of field experience can supply this information.

EXAMPLE I

Polymeric Type Antileak Hydraulic Oils

The incorporation of proper polymers into hydraulic oils are concentrations as high as 5% can provide leakage protection. As can be seen in Table I, a typical product containing a high molecular weight butene polymer also has good overall properties. The base oils, which are naphthenic in nature, have an aniline point of 152°F. and generally provide good rubber seal conditioning. Water separation, foam resistance, rust protection are all acceptable. The oxidation stability, as measured by the ASTM D-943 proceedure, is 1,250 hours. Leakage resistance, according to the laboratory test is approximately 41% less than that of a normal R&O hydraulic oil.

Two field trials were run with the polymeric antileak hydraulic oil. The results of these equipment evaluations are listed in Table II. In the first field trial listed, three broaches were run for a period of two months at each of three separate plant locations. The broaches were first run with the R&O hydraulic oil to determine baseline data. The polymeric antileak oil was then added to these same machines and consumption characteristics measured. As can be seen, the three divisions reported improvements of 46%, 88% and 50%, respectively. The second trial listed in Table II was run on a total plant basis. All machines using R&O hydraulic oil were studied for consumption during a 6 month period. These same machines were then charged with the polymeric antileak hydraulic oil for an equivalent 6 month period. After the one year trial, this plant measured a reduction in lubricant consumption of 28%. Table III lists 12 machines in the second plant trial which had the largest amount of leakage with the R&O type hydraulic oil. The machines covered a wide range of operations. In these pieces of equipment, the leakage reduction afforded by the polymeric antileak hydraulic oil was 39%, significantly more than the percentage reported for the total plant. Good leakage reduction is obtained with 1-6% polybutene (typically 2%).

The polymeric antileak lubricant after the field trials had experienced only the normal amount of degradation. Filter and valve operations were completely satisfactory. The one final property which had changed more than that of the R&O hydraulic oil was viscosity. The polymer loss by sheardown caused a viscosity decrease of approximately 10%. This loss did not cause any performance problems.

A polymer thickened antileak oil with good performance in the D-943 test comprises 2% of a polybutene additive, 0.6% DBPC, 0.7 % zinc dialkyl dithiophosphate and the remainder a blend of hydrorefined naphthenic oil and hydrocracked paraffinic oil, the blend having an aniline point of 200°F. and a viscosity at 100°F. of 300 SUS.

EXAMPLE II

Gel Type Antileak Hydraulic Oils

An antileak hydraulic oil was compounded using lithium stearate as a gel type leak retardant.

The gel type antileak hydraulic oil composition had a SUS viscosity of about 250 at 100°F. and was prepared from a 200 SUS (at 100°F.) base oil containing 56 ppm of basic nitrogen and obtained by blending 25% of 2400 SUS (at 100°F.) hydrorefined naphthenic oil and 75% of 100 SUS (at 100°F.) hydrorefined naphthenic oil. Both hydrorefined naphthenic oils were obtained from naphthenic acid-free naphthenic distillate by hydrogenation at 625°F., 1200 psig, of 80% hydrogen, 0.2 LHSV with a presulfided Ni-Mo-oxide catalyst. In addition to the base oil, the hydraulic oil contained 0.25% Li stearate, 0.17% of an amine type antioxidant (Dupont Ortholeum), 10 ppm of a defoamer (Dow Corning Silicone), 0.2% of a neutral barium petroleum sulfonate antirust agent, and 0.7% Zn dialkyl dithiophosphate (Elco 114). The Zn dialkyl dithiophosphate imparts especially useful antiwear and antioxidant properties to the hydraulic fluid and has excellent hydrolytic stability. The alkyl group of this additive can vary considerably, depending on the manufacturer; however, all such presently commercially available Zn dialkyl dithiophosphate antiwear additives can be used in the fluids of the present invention.

Specific gelling agents (e.g., Li or Al soaps) appear to be more efficient than the polymers in reducing leakage at concentrations up to 3%. The Al soaps are less hydrolytically stable than the Li soaps. Lubricants containing these materials are, however, also somewhat less stable to oxidation. The overall properties of the gel thickened hydraulic oil are good. A hydrogenated naphthenic type blended base oil with an aniline point of 160°F., for example, can be used to provide seal swell. Oxidation stability, as measured by the ASTM D-943 proceedure, is about 300 hours less than the polymeric version but about 200% better than a comparable oil containing naphthenic acid-free naphthenic distillate instead of the hydrorefined oil. The leak resistance of the gel type oil made from the hydrorefined base stock is twice as good as measured in laboratory equipment.

Field trial data was obtained with the gel antileak hydraulic oil of this example. Three presses were tested, one a horizontal type, and the other two vertical. These presses were operated from 880 hours to 1,944 hours. Leakage reduction when compared to the R&O hydraulic oil was 55%, 85% and 60%, respectively. These values are higher than the reductions reported for the polymeric antileak hydraulic oil. Filter and valve performance were completely acceptable. After this trial the condition of the product was excellent. There was not significant viscosity or acid buildup. A viscosity loss of about 15% occurred due to the sheardown of the gel, but there was still enough of the leak retardant present to maintain good leakage reduction.

Actual equipment testing has shown that polymeric antileak hydraulic oils can reduce losses by 23 to 88%. The gel containing antileak hydraulic oils are more efficient with reductions of 55 to 85% in plant equipment.

EXAMPLE III

An antileak hydraulic oil was compounded using the same blended (i.e., 100 SUS and 2400 SUS hydrorefined naphthenic oils) base oil as in Example II; however, the additives were different from those in Example II, namely, 0.7% ditertiarybutyl para cresol (DBPC), 0.05% alkyl (C ₈ -C ₁₈ ) substituted succinic acid (Lubrizol 850), 0.1% dioctyl dithio-thia-diazole (Amoco 150), 2 ppm silicone defoamer (1000 cSt at 100°F., Dow Corning 200 fluid). This hydraulic oil required about 1000 hours of ASTM D-943 testing to reach an acid number end point of 2.0 In contrast, a hydraulic fluid with the same additives but made from unhydrorefined naphthenic oil failed after 200 hours of D-943 testing.

Addition of zinc dialkyl dithiophosphate to provide 0.015% Zn in the final compounded oil imparts good antiwear properties.

EXAMPLE IV

Two antileak hydraulic oils were compounded using the additives in Example III (that is, one oil contained zinc dialkyl dithiophosphate) and as the base oil a 200 SUS blend of a 100 SUS hydrocracked paraffinic lube and a 500 SUS hydrocracked paraffinic lube. Both oils showed better D-943 test performance than the corresponding oils containing hydrorefined or unhydrorefined base oils.

EXAMPLE V

An antileak hydraulic oil was compounded using the same amount of lithium stearate and the same base oil as in Example I. The addition of 5% of a 200 SUS "Duo-Sol" extracted paraffinic lube having an aniline point of 226°F. improved the D-943 performance of the hydraulic oil. Similar results were obtained with 5% of a 152°F. aniline point blend of 25% 100 SUS and 75% 2500 SUS naphthenic acid-free naphthenic distillates or with 21/2% of the paraffinic oil and 21/2 of the naphthenic oil blend.

A 200 SUS hydrocracked paraffinic lube can be used instead of the paraffinic lube in this example.

The attached Table VI lists the properties of a series of hydrocracked oils (stabilized by solvent extraction) which are especially suitable components for blending with hydrogenated and/or unhydrogenated naphthenic oils and/or an aromatic concentrate to provide a suitable base stock having an aniline point in the range of 150°-170°F. For such blending, the following formula can be used to predict the aniline point (AP) of the blended base stock (AP Base):

Ap base = (X) (AP Paraffinic Component) + (1-X) (AP Naphthenic Component)

where X is the volume fraction of the paraffinic component and 1-X is the volume fraction of the naphthenic component.

An especially useful blended paraffinic component is obtained by blending 90 parts by volume of a 60 SUS at 100°F. hydrocracked paraffinic oil with 10 parts by volume of the unhydrorefined paraffinic oil (obtained by Duo-Sol extraction of a paraffinic distillate).

Another paraffinic component, which can also be used as a textile process oil (due, in part, to its high unsulfonatable residue) is obtained by substitution of the hydrocracked paraffinic oil for the solvent refined oil. Similar paraffinic components of higher viscosity and differing aniline points can be obtained by blending other hydrorefined and unhydrorefined paraffinic lube stocks of higher viscosity.

Some commercial additive packages contain aromatic compounds. The contribution of these aromatics to the aniline point of the base oil must be considered in calculations.

When the base oil contains a hydrocracked oil component, satisfactory seal swelling can be obtained at higher aniline points (e.g., about 200°F.).

An especially useful soap and polymer thickened oil, for lubrication of textile machinery, can be made by adding lithium stearate (or lithium palmitate, laurate, oleate, etc.) and high molecular weight polyisobutylene to ahydrogenated naphthenic oil having a viscosity in the range of 60-300 SUS at 100°F. For example, sufficient lithium stearate (0.7%) and polyisobutylene (1.9% Paratac) to produce a MacMichael viscosity of about 25 was added to a 150 SUS (at 100°F.) hydrorefined naphthenic lube (aniline point 162) to which there was also added 1.3% of 40% chlorinated paraffin (Chlorfin 40), to improve load carryability of the oil, 0.4 of ditertiarybutyl paracresol and 2 ppm of a silicone antifoam. This lithium soap thickened textile lubricant cannot be made with a paraffinic base oil of the same viscosity since the paraffinic oil is not sufficiently compatable with soap to permit attainment of the desired MacMichael viscosity. Unhydrorefined naphthenic oil canot be used in this oil because it causes discoloration and damage to textiles.

The soap thickened, antileak hydraulic oils described herein can be used as a functional fluid in energy adsorber devices, such as those which can reduce the body and bumper damage caused by automotive collisions (e.g., see Publications 710536, 710537 and 710540 of the Society of Automotive Engineers; mid year meeting, Montreal, Quebec, Canada on June 7-11, 1971. In such a combination the base oil should have an aniline point of about 200°F. when the seals are of silicone rubber.

An aluminum "complex" soap concentrate, which is useful in the present invention, can be made as follows (all parts are by weight):

Dissolve 0.7 parts benzoic acid in 500 parts of bright stock (or other high viscosity lube) at 220° F.

Dissolve 13 parts stearic acid in 450 parts of paraffinic bright stock (or other high viscosity lube) at 200° F.

Add Agrashell Kolate, 3 parts, to the stearic acid in oil, mix and stir (e.g., about 8 minutes).

Add the benzoic acid in oil to the stearic-acid-oil-Kolate, heat with stirring, to 400° F. then cool, with stirring to 220° F.

The concentrate is especially useful at levels which impart 0.1-1% Al complex soap to the final hydraulic oil composition.

Agrashell Kolate is a reactive oxoaluminum compound for making complex aluminum soaps and greases.

TABLE I ______________________________________ Polymeric Type Antileak Hydraulic Oil Lubricant Properties R&O Antileak ASTM Hydraulic Hydraulic Test Method Oil Oil ______________________________________ Viscosity, SUS/100° F. D2161 250 242 Viscosity, SUS/210° F. D2161 50.4 45.3 Viscosity, Index D2270 102 34 Viscosity, cs/100° F. D445 53.9 52.1 Viscosity, cs/210°F. D445 7.4 5.82 Flash, COC,°F. D92 440 335 Fire, COC, °F. D92 495 385 Pour, °F. D97 0 -25 Color D1500 2.0 2.25 Gravity, °API D287 31.2 21.2 TAN, mgKOH/g D664 0.07 0.0 Copper Strip, class D130 1 1 Aniline Point, °F. D611 230 152 Demulsibility/130° F. D1401 10 20 Separation, min. Foam, Tendency/Stability D892 Sequence I, ml 20/0 5/0 Sequence II, ml 20/0 25/0 Sequence III, ml 20/0 20/0 Rust, Syn Sea Water D665B Pass Pass Oxidation Stability, hr (1) D943 1,300 1,250 Leak Resistance -- Gms Leaked 110 65 Reduction,% -- 41 ______________________________________ (1) To 2.0 TAN end point.

TABLE II ____________________________________________________________ ______________ Polymeric Type Antileak Hydraulic Oil Plant Trial Data. Consumption, Gallons R&O Antileak % hl,39 Hydraulic Oil Hydraulic Oil Reduction ____________________________________________________________ ______________ #1 Plant Trial Per Broach per week* at Division A 5.7 3.1 46 Division B 23.1 2.7 88 Division C. 10.0 5.0 50 #2 Plant Trial Total plant usage** 3,131,667 2,242,766 28 Per unit manufactured .98 .75 24 ____________________________________________________________ ______________ * month duration ** 6 month duration

TABLE III ______________________________________ Polymeric Antileak Hydraulic Oil uz,1/32 #2 Plant Trial Leakage Comparison Most Critical Machines Average Weekly Consumption, Gallons R&O Antileak Type Equipment Hydraulic Oil Hydraulic Oil ______________________________________ Broach 108 57 Automated Drill line 41 33 Mill 12 19 Drill 217 155 Gear Cutter 140 112 Drill 198 35 Lathe 217 178 Broach 32 28 Gear Cutter 102 57 Grinder 28 6 Drill 23 16 Lathe uz,13/19 66 25 Total 1,184 721 % Reduction 39 ______________________________________

TABLE IV ______________________________________ Gel Type Antileak Hydraulic Oil Lubricant Properties R&O Antileak ASTM Hydraulic Hydraulic Test Method Oil Oil ______________________________________ Viscosity, SUS/100° F. D2161 250 258 Viscosity, SUS/210° F. D2161 50.4 45.5 Viscosity, Index D2270 102 23 Viscosity, cs/100° F. D445 53.9 55.6 Viscosity, cs/210° F. D445 7.4 5.9 Flash, COC, °F. D92 440 350 Fire, COC, °F. D92 495 390 Pour, °F. D97 0 -40 Color D1500 2.0 2.5 Gravity, °API D287 31.2 22.1 TAN, mgKOH/g D664 0.07 0.0 COpper Strip, class D130 1 1 Aniline Point, °F. D611 230 160 Demulsibility/130° F. D1401 Separation, min. 10 25 Foam, Tendency/Stability D892 Sequence I, ml 20/0 5/0 Sequency II, ml 20/0 25/0 Sequence III, ml 20/0 5/0 Rust, Syn Sea Water D665B Pass Pass Oxidation Stability, hr (1) D943 1,300 900 Leak Resistance -- Gms Leaked 110 20 Reduction, % -- 82 ______________________________________ (1) To 2.0 TAN end point.

TABLE V ____________________________________________________________ ______________ Gel Type Antileak Hydraulic Oil Plant Trial Data ____________________________________________________________ ______________ Equipment Type Horizontal Press Vertical Press Vertical Press Ram Diameter 12" 22" 36" Oil Capacity 150 gal 200 gal 300 gal Operation Pressure 1500 psi 1000 psi. 1500 psi Temperature Ambient 150°F 125°F Duration 880 hr 1944 hr 1400 hr Leakage R&O Hydraulic Oil 75-100 gal/wk 50 gal/wk 125 gal/wk Hydraulic Oil 35-40 gal/wk 7 gal/wk 50 gal/wk Reduction, % 55-60 85 60 ____________________________________________________________ ______________

TABLE VI ______________________________________ Properties of Hydrocracked Oils* Aniline Viscosity ASTM Gravity Wt.% Point (SUS, 100° F.) VI API Aromatics °F. ______________________________________ 100 103 34.2 12 220 200 107 33.3 11 235 500 107 31.5 13 250 ______________________________________ * All oils dewaxed to a 0° F. pour point by chilling in a solvent.