US3088911A - Lubricant containing ashless antiwear additives - Google Patents

Description

nited rates Patent ii 3,088,91 l Patented May 7, 1963 This invention relates to improved lubricating oil compositions containing additives that function as wear-reducing agents. The antiwear additives of the invention are particularly characterized by the fact that they are metalfree, thus permitting them to be used where either ashless compositions or compositions relatively low in ashforming tendencies are desired. The additives of this invention also have the desirable property of not contributing materially to oxidation or corrosion instability.

In the formulation of crankcase lubricants for pistontype internal combustion engines for automotive use, the recent trendhas been to employ viscosity index improvers, oxidation inhibitors, and detergents in order that the lubricant may serve its purpose under a wide variety of conditions, including high-speed driving for sustained periods as well as low-speed stop-and-go driving at relatively low temperatures. The detergents and oxidation inhibitor additives enable the oil to keep the various parts of the engine free of varnish and cokelike deposits. At the same time, these additives prevent or at least minimize the formation of sludge and also hold in suspension any sludge that may be formed. There is one major disadvantage to detergents and inhibitors in crankcase lubricants, however, and that is that they keep the wearing surfaces of the engine particularly clean. For this reason, they contribute to a higher degree of wear than would occur if there were no detergents and inhibitors present. This problem of wear with high detergency oils shows up particularly in the valve train of automotive engines and especially in the valve lifter mechanism. In the valve lifter mechanism, pressures as high as 100,000 lbs. per square inch can exist between the valve lifter and its actuating cam. For this reason, in present-day high detergency crankcase lubricants, there is a need for antiwear additives.

While in the past certain metal salts such as molyb denum sulfide and the zinc salts of alkyl dithiophosphoric acids have been used as additives for reducing wear, such metal salts have a disadvantage in that they increase the over-all metal content of the lubricating oil. The oil composition may already be unduly high in metal content because of the presence of such detergent-inhibitors as overbased metal sulfonates, metal salts of alkyl phenol sulfides, metal carbonate dispersions, and the like. It is sometimes considered undesirable to have large quantities of metal present in a crankcase lubricant because the metal may contribute to combustion chamber deposits which promote preignition. It is self-evident that an antiwear agent which does not add to the metal content of the lubricant will have a considerable advantage. Also, there are obvious advantages for an ashless antiwear additive in a formulation where the detergentinhibitor is of the ashless variety.

It has now been found that the mono salts (i.e. the half salts) formulated by the partial neutralization of chlorendic acid with long chain aliphatic amines of from about 12 to 24 carbon atoms are useful as ashless antiwear additives for lubricating oils. Particularly useful are the mono salt prepared from a C C aliphatic amine mixture of about 300 molecular weight marketed commercially as Primene IMT by Rohm and Haas 'Co., and the mono salt prepared from mixed hexadecyl and octadecylamines of about 260 molecular weight marketed by Armour and Co. as Armeen HT. Other commercially available amines of this type include Duorneen T (sometimes identified as N-tallow-1,3-diaminopropane), Armeen CD (technical dodecylamine) and Primene 81R, which is a mixture of C to C aliphatic amines.

Chlorendic acid may be referred to as a dicarboxylic acid derivative of a polychlorinated cyclopentadiene. This acid may also be identified as l,4,5,6,7,7-hexachlorobicyclo(22l)-5-heptene-2,3-dicarboxylic acid and has the formula 0 II Gl-C-Cl 6 O l OOH /I II C H O 51 Chlorendic acid may be prepared by the Diels-Alder addition of maleic anhydride to hexachlorocyclopentadiene and subsequent hydrolysis.

The invention will be more readily understood when reference is made to the following examples.

EXAMPLE 1 EXAMPLE 2 The double salt of 'Primene JMT and chlorendic acid was prepared in the manner of Example 1, using a ratio of 2 moles of amine to 1 mole of acid.

EXAMPLE 3 The Armeen HT mono salt of chlorendic acid was prepared by dissolving 10.36 grams of Armeen HT (0.04 mole) in ml. of toluene and then adding this solution to 15.54 grams (0.04 mole) of chlorendic acid. Toluene was then removed by heating the solution on a steam bath and blowing the product with air. The mono salt was recovered as a highly viscous residue.

EXAMIPLE 4 The Primene JMT salt of monochlorodifiuoroacetic acid was prepared by adding 43.5 grams (0.33 mole) of monochlorodifiuoroactic acid to grams (0.33 mole) of Primene J MT with stirring. The reaction was exothermic but no external cooling was employed. The product was a red-brown thick oil.

EXAMPLE 5 In the same manner as in Example 4, the Primene JMT salts of trichloroacetic acid, monochloroacetic acid, and heptafluorobutyric acid were prepared by reaction of equimolar proportions of the amine with the respective acids.

EXAMPLE 6 Using as the base stock a refined mineral white oil having a viscosity of 78 centistokes at 100 F., a number of blends were prepared each containing 1 wt. percent of phenyl alpha naphthyl amine as a corrosion and oxidation inhibitor and 0.5 wt. percent of one of the salts described in Examples 1, 2, 4, and 5. Each of the compositions was subjected to an oxidation and corrosion stability test at 347 F., conducted in accordance with Method 5308.4 of Federal Test Method Standard No. 791 as outlined in Military Specification MIL-L-7808D. The corrosion and oxidation results obtained with each of the compositions are presented in Table I. It will be noted that the chlorendic acid mono salt of the present invention exhibited low corrosion tendencies toward the various metals. Furthermore, the mono salt of the present invention showed much less oxidation promoting tendency than any of the other salts as demonstrated by the markedly lower increase in viscosity and the much lower total acid number of the oil at the end of the test.

Table I RESULTS OF OXIDATION AND CORROSION STABILITY TESTS AT 347 F. ON VARIOUS PRIMENE JMT SALTS OF HALOGENATED ACIDS Chlorendie Chlorendic Trichloro- Chloro- Chloro- Hcptw- Corrosion Results None Acid Acid acetic acetic difluorfluoro- Double Mono Acid Acid acetic butyrlc Salt Salt Acid Acid Metal Wt. Change mgJcmfi: Cu +0. 01 5. 1 0. 42 0. 20 0. 77 -1.02 -0. 29 Mg- +0. 04 +0. +0.02 +0. 16 +0. 02 +7. 6 Fe 0 0 +0.01 +0. 01 +0. 04 0. 01 0. 01 AL... V 0 +0. 02 +0. 02 +0.02 +0. 04 0 '0. 03 Ag +0. 03 +0. 00 +0. 04 -0. 04 +0.07 +0. +0. 04 Oxidation Results: v r

ViS. at 100 F., 05---..- 83. 2 100. 15 92. 6 124. 8 123. 9 127. 4 148. 0 Total Acid Number" 0.64 3. 85 0. 65 4.11 5.01 5.78 3. 48

EXAMPLE 7 as for example the complex ester formed by the reaction Compositions were prepared using as the base oil a high viscosity index mineral oil composition containing a mixture of copolymeric type viscosity index improvers and meeting the viscosity specifications of an SAE 10W-30 motor oil. The base oil also contained 0.2 wt. percent of a pour point depressant and 0.06 wt. percent of a polyethylene glycol dioleate rust inhibitor. All of the compositions contained equal amounts of a detergent-inhibitor comprising a stabilized colloidal barium carbonate-phenate complex. One composition contained 1 wt. percent of sulfurized sperm oil; the second composition contained 1 wt. percent of the mono salt of Primene JMT and the chlorendic acid prepared as in Example l; and the third contained the mono salt of Armeen HT and chlorendic acid prepared as in Example 3.

Each of these compositions was tested in the wellknown Shell four-ball wear testing machine. The test is conducted as follows. The test lubricant is placed in the cup of the machine and heated to 200 F. The test cup contains three steel balls which are fixed in position by a screw cap. A fourth steel ball, which is held in a chuck, is pressed against the three lower balls with a force of 40 kilograms and is rotated at a speed of 600 rpm. for a period of 2 hours. At the end of the test, the amount of Wear is determined by measuring the diameter of the wear scar on each of the three lower balls and averaging the results.

The compositions of the three blends tested and the wear results obtained are given in Table II. It will be seen that there was much less wear with the compositions containing the salts of the present invention as compared with the composition containing sulfurized sperm oil, which has been used in the past for reducing wear.

Table II FOUR-BALL WEAR TESTS 1 51. 8 wt. percent concentrate in mineral oil, 10. 61 BaO content.

of 1 mole of sebacic acid with 2 moles oftetraethylene glycol and 2 moles of Z-ethyl hexanoic acid.

The additives of this invention are particularly appli cable for use in lubricating oil compositions containing viscosity index improvers, e.g., polymethacrylates, poly butenes, etc., and detergent-inhibitors, e.g. metal sulfo nates, metal alky'l phenol sulfides, metal carbonate sols, phosphosulfurized hydrocarbon derivatives, and the like. The lubricant compositions may also contain antioxidants, e.g. phenyl-alpha-naphthylamine, his phenols, etc., pour point depressants, dyes, and other additives for improving the properties of the compositions.

The antiwear additives of the invention may also be employed in conjunction with any of the ashless types of detergents, for example, those of the high molecular weight polymeric type having molecular weights of up to about 50,000. One example is a copolymer of 65 to weight percent of mixed (l -C fumarates, 10 to 20 weight percent of vinyl acetate, and 5 to 15 weight percetn of N-vinyl pyrroiidone. Another example is the copolymer derived by reaction of mixed tallow furnarates and C oxo fumarates, averaging about 420 molecular weight, with vinyl acetate in a 3 to 1 acetate fumarate ratio, and 3 weight percent of maleic anhydride, followed by subsequent removal of excess vinyl acetate. By tallow fium-arates is meant the esters of fumaric acid and the alcohols derived by hydrogenation of tallow. The latter are principally C and C alcohols with minor amounts of C C and C alcohols. C oxo alcohols are prepared rby reaction of carbon monoxide and hydrogen on mixed C C olefins followed by hydrogenation of the resulting aldehyde/s.

The compositions embodying the additives of this invention include not only automotive crankcase lubricants but also such other lubricants and fluids as turbine oils, various industrial oils, hydraulic fluids, transmission fluids, and the like. A particular application of the additives is as a replacement for zinc salts of dialkyl dithiophosphoric acids as antiwear agents in fluids for automatic transmissions, where the zinc salts suiier the disadvantage of poor lheat stability at high temperatures, e.-g. 300 F. or higher. The compositions of Example 7 can serve as automatic transmission fluids for example.

The antiwear additives of this invention may be employed in lubricating compositions in concentrations ranging from about 0.01 to about 5 percent by weight, preferably about 0.1 to about 2 percent by weight.

It is to be understood that the examples presented herein are intended to be merely illustrative of the invention and not as limiting it in any manner; nor is the invention to be limited by any theory regarding its operability. The scope of the invention is to be determined by the appended claims.

What is claimed is:

1. An improved lubricating composition h-avin-g superior antiwear properties which comprises a major proportion of an oil of lubricating viscosity grade into which has been incorporated from about 0.01 to about 5 weight percent of the mono salt of chlorendic acid and an aliphatic amine having in the range of from 12 to 24 carbon atoms.

2. The lubricating composition as defined by claim 1 15 wherein said lubricating oil is a mineral oil.

3. The lubricating composition as defined by claim 1 which includes a detergent additive.

5 wherein said amine comprises mixed hexadecyl and octadecyl amines.

References Cited in the file of this patent UNITED STATES PATENTS 2,733,248 Lidov Jan. 31, 1956 2,771,423 Dorinson Nov. 20, 1956 2,971,913 David et a1. Feb. 14, 1961 OTHER REFERENCES HET Acid, Hooker Electrochemical Co., Niagara Falls, 1952, page 4.

Claims (1)

1. AN IMPROVED LUBRICATING COMPOSITION HAVING SUPERIOR ANTIWEAR PROPERTIES WHICH COMPRISES A MAJOR PROPORTION OF AN OIL OF LUBRICATING VISCOSITY GRADE INTO WHICH HAS BEEN INCORPORATED FROM ABOUT 0.01 TO ABOUT 5 WEIGHT PERCENT OF THE MONO SALT OF CHLORENDIC ACID AND AN ALIPHATIC AMINE HAVING IN THE RANGE OF FROM 12 TO 24 CARBON ATOMS.