US3532626A - Lubricant compositions - Google Patents

Description

Int. Cl. Cm 1/54," 1/48 US. Cl. 252-32.7 6 Claims ABSTRACT OF THE DISCLOSURE Lubricant compositions are provided containing a small amount, sufiicient to improve anti-wear properties of a mixture of a metal salt of an 0,0-diorgano-phosphorodithioate and a boroxaryl compound.

This invention relates to improved organic compositions and, in one of its aspects, relates more particularly to improved organic compositions in the form of liquid and solid hydrocarbon-containing materials that are normally deficient in anti-wear properties under conditions of use. Still more particularly, in this aspect, the invention relates to improved organic compositions in the form of lubricating oils and greases which, in their uninhibited state, tend to react with and corrode metal surfaces with which they may come into contact, in the form of chemical wear, in performing their intended function, or which, in their uninhibited state, exhibit poor anti-wear properties under conditions of use.

It is well known that lubricating oils, and greases containing such oils as lubricating vehicles, are subject to a certain amount of deterioration or cause wear of metal surfaces under conditions of use, as, for example, as lubricants in internal combustion engines, and as lubricants for various types of mechanical elements. More specifically, the products which are formed in the oil are acidic in nature and exert a deteriorative effect on metal parts with which the oil comes into contact. Furthermore, these products produce formations of varnish and sludge on engine surfaces, thus lowering the operating efliciency of the engine. Similarly, it is known that solid lubricants, in the form of greases, tend to have their lubricating properties impaired under the stress of environmental use and thus may be ineffective with respect to exhibiting good anti-wear properties.

It is therefore, an object of the present invention to provide organic compositions having improved anti-wear properties.

Another object of the invention is to provide improved organic compositions in the form of liquid and solid hydrocarbon-containing materials, as lubricants, containing additives adapted to prevent the aforementioned Wear and deterioration of metallic surfaces.

Still another object of the invention is to provide effective anti-wear additives for incorporation into the aforementioned organic compositions.

Other objects and advantages inherent in the invention will become apparent to those skilled in the art from the following more detailed description.

It has now been found that organic compositions, normally susceptible to deterioration, particularly in the form of lubricating oils and greases, can exhibit reduced deterioration and improved anti-wear properties by incorporating into such compositions a small amount, suflicient to inhibit said deterioration and wear of a mixture comprising (a) a metal salt of an 0,0-di-organo-phosphorodithioate and (b) a boroxaryl compound.

In general, the present invention, in its preferred applications, contemplates organic compositions which are normally ineffective or insufficient in controlling wear, which contain a small amount of the aforementioned additive 3,532,626 Patented Oct. 6, 1970 mixture, usually from about .01 to about 10 percent, and preferably from about .01 to about 5 percent, by weight, of the total weight of such composition. Insofar as the additive mixture, itself, is concerned, the components (a) and (b) described above, may be individually present in an amount from about 5 to about percent, by weight, of the total of the mixture. A field of specific applicability is the improvement of liquid hydrocarbons, employed as lubricants, including any of the conventional hydrocarbon oils of lubricating viscosities. These may include mineral or synthetic lubricating oils, aliphatic phosphates, esters and diesters, silicates, siloxanes, oxalkyl ethers, or esters. Mineral lubricating oils, employed as the lubricating composition, may be of any suitable lubricating viscosity, and range from about 45 SSU to about 6,000 SSU at F., and, preferably, from about 50 to about 250 SSU at 210 F. These oils may have viscosity indexes from below 0 to about 100 or higher. Viscosity indexes from about 70 to about 95 are preferred. The average molecular weights of these oils may range, for example, from about 250 to about 800.

As previously indicated, the aforementioned additive mixtures may also be incorporated as anti-wear and antioxidative agents in grease compositions. Such greases may comprise a combination of a wide variety of lubricating vehicles and thickening or gelling agents. Thus, greases in which the aforementioned additive mixtures are particularly effective may comprise any of the aforementioned conventional hydrocarbon oils of lubricating viscosity, as the oil vehicle, and may include any of the aforementioned mineral or synthetic lubricating oils of the type indicated.

With respect to the formation of improved grease compositions in which the aforementioned additive mixtures are to be incorporated, the choice of employing a mineral or a synthetic oil of lubricating viscosity can best be determined from the nature of the intended environmental use for the grease. Thus, when high temperature stability is not a requirement of the finished grease, mineral oils having a viscosity of at least 40' SSU at 100 F., and particularly those falling within the range from about 60 SSU to about 6,000 SSU at 100 'F. may be effectively employed. In instances where synthetic vehicles are employed rather than mineral oils, or in combination therewith as the lubricating vehicle, various compounds of this type may be successfully utilized. Typical synthetic vehicles include: polypropylene, polypropylene glycol, trimethylol propane esters, neopentyl and pentaerythritol esters, di-(-ethyl hexyl) sebacate, di-(Z-ethyl hexyl) adipate, di-butyl phthalate, fluorocarbons, silicate esters, silanes, esters of phosphorus-containing acids, liquid ureas, ferrocene derivatives, hydrogenated mineral oils, chain-type polyphenyls, siloxanes and silicones (poly-siloxanes), alkyl-substituted diphenyl ethers exemplified by a butyl-substituted bis(p-phenoxy phenyl) ether, phenoxy phenyl ethers, etc.

The lubricating vehicles of the aforementioned improved greases of the present invention containing the above-described additive mixtures are combined with a grease-forming quantity of a thickening agent. For this purpose, a wide variety of materials may be employed. These thickening or gelling agents may include any of the conventional metal salts or soaps which are dispersed in the lubricating vehicle in grease-forming quantities in such degree as to impart to the resulting grease composition the desired consistency. Other thickening agents that may be employed in the grease formulation may comprise nonsoap thickeners, such as surface-modified clays and silicas, aryl ureas, calcium complexes and various other materials. In general, grease thickeners may be employed which do not tend to melt and dissolve when used at the required temperature Within a particular environment;

3 however, in all other respects, any material which is normally employed for thickening or gelling hydrocarbon fluids for forming greases, can be used in preparing the aforementioned improved greases in accordance with the present invention.

The metal salts of the 0,0-di-organo-phosphorodithioate component of the novel additive mixtures of the present invention are, in general, prepared by the method set forth in US. Pat. 3,102,096, and the disclosure thereof is incorporated herein, in its entirety, by reference. More specifically, in these metal salts the organo radical may comprise an aryl radical, such as phenyl, naphthyl or the like. These radicals may be completely unsubstituted or they may also have alkyl groups substituted thereon. In the latter instance, the aryl radical may preferably have from about 1 to about 5 alkyl groups, each containing from about 1 to about 20 carbon atoms substituted thereon. The organo radical may also comprise an alkyl radical, containing no aryl substituents, preferably containing from about 1 to about 20 carbon atoms. Any metal may be employed for forming the aforementioned metal salts, and particularly preferred are zinc, copper, mercury, iron, lead, cadmium, silver, nickel and chromium. Representative examples of these metal salts include the 0,0-di-arylphosphorodithioates, such as metal bis(phenyl)dithiophosphates; metal bis(naphthyl)dithiophosphates; metal bis(tolyl)dithiophosphates; metal bis(t-amylphenyl)dithiophosphates; metal bis(didodecylphenyl)dithiophosphates; and metal bis(waxphenyl)dithiophosphates. Representative examples of these metal salts in the form of the 0,0-di-alkyl-phosphorodithioates include such salts as metal bis(2,2-dimethyl-1-propyl)dithiophosphates; metal bis(2,2,4-trimethy1 l-pentyl)dithiophosphates; metal bis (2,2-dimethyl-l-decyl) dithiophosphates; and metal bis (2,2,4-trimethyl-l-hexadecyl) dithiophosphates. Particularly elfective are the zinc and mercuric 0,0-di-alkylphosphorodithioates, particularly representative of which are zinc and mercuric 0,0-di-isopropylphosphorodithioates.

The boroxaryl component of the novel additives mixtures of the present invention comprises boroxarophenanthrenes of which 9,IO-boroxarophenanthrenes are representative. The preparation of the 9,l0-boroxarophenanthrenes, in general, is known to the art and may be prepared, for example, by the methods described by Dewar and Dietz, Journal Chemistry Society (London), 1344 (1960).

The preparation of 9-hydroxy 9,10-boroxarophenanthrene is exemplary of these procedures. More specifical- 1y, orthophenylphenol is reacted with excess boron trichloride. The intermediate product from this reaction is then heated in the presence of aluminum chloride to give 9-chloro 9,IO-boroxarophenanthrene. This chloro compound is then treated with water to give the desired 9- hydroxy-9, lO-boroxarophenanthrene.

The aforementioned 9,10-boroxarophenanthrene may be represented by the following structural formula:

where R is selected from the group consisting of hydroxy, hydrocarbyl, oxy-hydrocarbyl, halogen, halogenated hydrocarbyl, halogenated oxy-hydrocarbyl, and oxy 9,10- boroxarophenanthrene groups; R is selected from the group consisting of hydrocarbyl, halogen and halogenated hydrocarbyl groups; and n is 0 to 4.

As used herein, by the term hydrocarbyl is meant groups composed of carbon and hydrogen atoms such as 4 aliphatic, aryl, aliphatic-aryl, both alkaryl and aralkyl, and cycloaliphatic groups.

Suitable substituents for R include the above-mentioned hydroxy group as well as alkyl groups, both straight-chain and branched-chain, such as methyl, ethyl, propyl, isopropyl, tert.-butyl, octyl, dodecyl, hexadecyl, octadecyl, tetracosyl, triacontyl, 'etc.; aryl groups such as phenyl, naphthyl, etc.; aliphatic-aryl groups including tolyl, amylphenyl, phenyloctyl, and the like; cycloaliphatic groups such as cyclohexyl; oxy-hydrocarbyl groups such as any of the aforementioned hydrocarbyl groups attached to an oxygen atom, e.g., alkoxy, aryloxy groups, etc.; halogens such as chlorine, bromine, iodine; halogenated hydrocarbyl and halogenated oxy-hydrocarbyl groups additionally containing one or more halogen atoms. The R substituents may be selected from any of the hydrocarbyl, halogen, and halogenated hydrocarbyl groups hereinabove described as suitable for R.

Hydrocarbyl, oxy-hydrocarbyl, halogenated hydrocarbyl and halogenated oxy-hydrocarbyl groups containing from 1 to about 30, particularly from 1 to about 18 carbon atoms are preferred substituents.

Some examples of the 9,10 boroxarophenanthrene compounds used in accordance with the present invention are:

9-hydroxy-9,10-boroxarophenanthrene,

di-octadecyl-9-hydroxy-9',10-horoxarophenantherene,

the anhydride of 9-hydroxy-9,l0-boroxarophenanthrene,

9-tert.-butoxy-9,l0-boroxarophenanthrene,

9-methoxy-9, IO-boroxarophenanthrene,

9-chloro-9,lO-boroxarophenanthrene,

9-pheny1-9,10-boroxarophenanthrene,

the 1,1,7-trihydroperfiuoro-heptyl ester of 9-hydroxy- 9,10-boroxarophenanthrene,

the 2,2-difluoro-dodecyl ester of 9-hydroxy-9,l0-

boroxarophenanthrene,

1,3-dibromo-9-hydroxy-9,l0-boroxarophenanthrene,

1,3,7-tribromo-9,lO-boroxarophenanthrene, and

5, l2-di-n-hexadecoxy-5, l 2-dibora-6, l 3-dioxaro dibenz [a,h] anthracene.

As indicated above, the additives of the novel organic compounds of the present invention comprise mixtures of the aforementioned (a) metal salts of 0,0-di-organophosphorodithioates and (b) boroxaryl compounds. In this respect, it is found that although each of the aforementioned components (a) and (b) are, individually, effective in inhibiting deterioration of organic compositions, nevertheless, when employed in admixture, a pronounced synergistic effect is obtained in which the efiicacy of each of components (a) and (b) is, pronouncedly, more than merely additive. This synergistic effect is observed with any ratio of components (a) and (b) being present in combination. Particularly effective agents comprise mixtures in which components (a) and (b) are individually present, as previously indicated, in an amount from about 5 to about percent, by weight, of the additive mixture.

The following examples will serve to illustrate the synergistic effect of the aforementioned components (a) and (b) in the additive mixtures of the novel organic compositions of the present invention in inhibiting wear, particularly with respect to lubricants in the form of lubricating oils.

Component (a) in the examples of the following table is either zinc (0,0-di-isopropylphosphorodithioate or mercuric 0,0-di-isopropylphosphorodithioate, and component (b) is either 9-hydroxy-9,10-boroxarophenanthrene or 5,12-di-n-hexadecoxy-5,l2-dibora-6,l3-dioxarodibenz-[a,h] anthracene. The base fluid is cetane (n-hexadecane). As shown in the table, the uninhibited base oil containing the aforementioned additive compounds, individually, as well as in admixture, were subjected to an antiwear test in order to ascertain synergistic effects. This test is carried out as follows.

A stationary pin is held upright against an axiallymounted rotatable disc, and the disc is rotated at a constant velocity. The pin describes a circle on the surface of the disc concentric with the axis thereof. Both pin and disc are submerged in a vessel holding the test lubricant, so that the point of contact between the pin and the rotating disc is lubricated at all times. The pin and the disc are each made of either AISI 1020 or AISI 4140 steel. The pin has a hemispherical tip, and the disc is 7.6 cm. in diameter. The force of the disc against the pin may be changed by varying the load outside of the lubricant vessel.

The lubricating fluids, shown in the table, were tested at a load of 8 kg. using a sliding velocity of centimeters per second. The tests were run at the temperatures indicated in the table, in a base fluid of cetane (n-hexadecane). After the test was completed, the pin was microscopically examined to measure the wear scar diameter. The wear rate was determined from this measurement.

SYNERGISM IN FRICTION AND WEAR BETWEEN METAL 0,0-

COMPOUNDS I claim:

1. A hydrocarbon lubricating oil containing antiwear synergistic proportions of 9-hydroxy-9,10 boroxarophenanthrene and zinc 0,0-diisopropylphosphorodithioate.

2. A hydrocarbon lubricating oil containing antiwear synergistic proportions of 9-hydroxy-9,1O boroxarophenanthrene and mercuric 0,0-diisopropylphosphorodithioate.

3. A hydrocarbon lubricating oil containing antiwear synergistic proportions of 5,12-di-n-hexadecoxy-5,12-dibora-6,l3-dioxarodibenz-[a,h] anthracene and zinc 0,0- diisopropylphosphorodithioate.

4. A synergistic mixture of 9-hydroxy-9,10 boroxarophenanthrene and zinc 0,0-diisopropylphosphorodithioate.

5. A synergistic mixture of 9-hydroxy-9,10 borozarophenanthrene and mercuric 0,0-diisopropylphosphorodithioate.

DIISOPROPYLPHOSPHO RODITHIOATES AND B OROXARYL X Coefit. Wear rate, Coefi. Wear rate. i io f Additive Temp, C. friction cc./cm. friction ccJcm.

l Base fluid (blank) 93.3 1.2 250, 000 10- 1,0 5,500 10-n 2.... 0.2% 9-hydroxy-9,10 boroxarophenanthrene.... 93. 3 0. 34 (10- 0.10 0. X10 3.... 0.38% zinc 0,0-diisopropylphosphorodithioate 93.3 0. 43 180. 0 1O- 0.28 23 1o- 4 0.10% 9-hydr0xy-9,10 boroxarophenanthrene/0.19% zinc 0,0411 opropylphosphorodithioate 9 0.06 .8 10 0.09 0.090X10- 5 0.48% mercuric 0,0-diisopropylphosphorodithioate. 93. 3 0.21 4. 4X10- 6.... 0.10% 9-hydroxy-9,10 boroxarophenanthrene/O.24% In our 0,0-d11s0propy1- phosphorodithioate 93. 3 0. 16 0. 47X10- 8 0 00% 5,12 (11 n hexadecoxy lbora 6 93. 3 O. 03 2 OXHH 0. 03 0. 05Xl0 0.19% zinc 0,0-diisopropylphosphorodithioate As will be apparent from the data of the foregoing table, the synergistic mixtures of the addition agents, in accordance with the present invention, as shown in Examples 4, 6 and 8 are markedly effective in inhibiting organic compositions, and lubricants in particular, against deterioration or in wear of metal surfaces.

Furthermore, it will be understood that the improved organic compositions of the present invention may, if so desired, contain various other additives or mixtures of such additional additives in order to further enhance their properties. It will also be understood that although the present invention has been described with preferred embodiments, various modifications and adaptations thereof may be resorted to, without departing from the spirit and scope of the invention, as those skilled in the art will readily understand.

6. A synergistic mixture of 5,12-di-n-hexadecoxy-5,12- dibora-6,13-dioxarodibenz [a,h] anthracene and zinc 0,0-diisopropylphosphorodithioate.

References Cited DANIEL E. WYMAN, Primary Examiner I. VAUGHN, Assistant Examiner U.S. Cl. X.R. 252-496, 400

gg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 2.622.626 Dated October 5 1970 Inventor/(4f CARLETON Na ROWE It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

'1 Colunm 3, line 40, for "additives" read ---a,dditive---.

Column 5, Table (Example 8 last column), for "0.05xl0 read --0.05xlO" SIGNED AND QEALED v 1 Efiward M. member, I: l Aflesting m 1 m L. s onuor Patents