US2939843A - Antiweld and antiwear lubricating oil composition - Google Patents

Description

Patented June 7, 1960 halogenated phosphite ester used, but in general should not exceed about five times by weight the amount of free I 2,939,843 sulfur present in the oil. For example, if the oil contains 02% of free sulfur, the phosphite should not ex- ANTIWELD WE fi 5 ceed about 1% by weight of the oil composition. a In preparing lubricating oils in accordance with our John N. Bowden and Paul R. Chapman, Crystal Lake, invention, a mineral lubricating oil of desired viscosity 11]., assignors to The Pure Oil Company, g and other properties is blended with about 0.5 to 5% of wrpol'atloll of 01110 lead naphthenate and 0.05 to 1% of sulfur. An oil of this compositionhas excellent load-carrying characteris- No Drawing' Filed 1956 605,697 ties as indicated by the four-ball weld test, but has a poor 4Claims. ((1252-5873) wear-preventive characteristics as demonstrated by the four-ball, 5-minute wear test. The four-ball test for determining load-carrying and wear properties is briefly deinvention relates to lubricating oils and more scribed on pages 13 and 14 of The Performance of particularlyto lubricating oils capable of withstanding Lubricating Oils, by 'Zuideman, published in 1952 by high loads. Reinhold Publishing Corp., New York. To improve the It. is common practice to incorporate into mineral lubriwear characteristics of this oil, a small amount of a eating oils intended for lubricating automotive gears and halogenated phosphite ester of the order of 0.1 to 5% by other mechanical parts subject to extreme pressures, adweight is incorporated in the oil. As examples of haloditives which are capable of enhancing the load-carrying genated phosphite esters which may be used are tri(chloproperties of the oil. Among the additives commonly roethyl) phosphite, chlorooctyl dihydrogen phosphite, used for this purpose, particularly in break-in oils or di(chlorooctyl) hydrogen phosphite, tri(bromopropyl) oils intended for lubricating green gears, are lead phosphite, tri(bromohexyl) phosphite, di(bron1oheptyl) naphthenate and free sulfur. Lead naphthenate and free hydrogen phosphite, tri(chlorooctyl) phosphite, tri(chlosulfur, however, have the drawbrack of causing high robutyl) phosphite, tri(chloroamyl) phosphite, and triwear under low speed-high torque conditions. In other (chlorolauryl) phosphite. The partial esters may be so words, although the combination of lead naphthenate strongly acidic as to be corrosive to the metal, in which and sulfur impart satisfactory anti-weld characteristics case either the quantity of the partial ester in the blend to the oil; it is not a satisfactory E.P. additive combinacan be reduced, or the blend can be treated withbasic tion under the varied conditions encountered in service. oxides or hydroxides, such as those of calcium, barium, We have discovered that if a small amount of a halozinc, lead, etc., or with basic nitrogen compounds, such alkyl phosphite is incorporated into the oil containing as ammonia and amines, in order to eliminate corrosivity. sulfur, with or without lead naphthenate, the anti-wear Haloalkyl phosphites containing from 1 to 30 carbon properties of the oil are materially improved while the atoms in the alkyl radicals are satisfactory, as long as anti-weld properties of the oil remain at a high level. the compounds are substantially non-volatile under'serv- An object of our invention is to provide a new lubriice conditions and are sufliciently soluble in the oil so cating oil composition. Another object of our invention that they remain in solution and will not precipitate out is to provide an extreme pressure gear oil which is satisduring Storage 1' in Se icefactory both under high speed-low torque and low speed- 40 In order to illustrate the invention, a number of blends high torque operating conditions. A still further object were prepared by mixing with mineral lubricating oil, of the invention is to provide a lubricant having good lead naphthenate, sulfur and several different phosphorus anti-wear and anti-weld properties. Other objects of the compounds until a homogeneous solution was obtained. invention will manifest themselves from the following Blends were tested on the four-ball machine. The results description. of the tests are given in the following table.

Table I Blend Number Composition, parts by weight 1 2 3 4 0 6 7 8 Lead naphthenate 4. 0 4. 00 4. 0 4. 0' 4. 0 Sulfur l 0. 2 0.08 0. 1 o. 1 0. 1 ErKchloroethyDphosphite.. 1.0 1 00 xtract-PgS reaction product.-. 1.0 Dicetyl dithiophosphorie acid 1. 0 Zinc salt of extract-P 8; reaction product 1. Mineral oil 94. 8 s4. 92 94. 9 94. 9 94. 44335 121. Machine 5 minute wear, 2() kg.

scar diameter (mm.) 0.389 0. 30s 0. 412 0.299 0. 30s 0. 419 0.386 0.389 Weld point (kg.) 170-180 530-540 810 1500-500 400 460-480 420 460-480 In carrying out our invention it is important to adjust the quantities of sulfur and haloalkyl phosphite so that the phosphite does not markedly detract from the antiweld properties of the sulfur and lead naphthenate. We have found that if the proportion of phosphite to sulfur is too large, although the-anti-wear properties of the oil are improved, the anti-weld properties are reduced below a satisfactory level so that the oil will not operate satisfactorily as a break-in oil for green gears. The amount of phosphite will depend to some extent on the particular From an examination of the table it will be seen that lead naphthenate alone imparts relatively poor loadcarrying and wear-resistant properties to the oil as measured by the weld point and scar diameter. Incorporation of 0.1% of sulfur materially increases the loadcarrying properties as demonstrated by the increase in the weld point, but the wear-resistance of the oil is adversely affected by the incorporation of the sulfur. This tendency to detract from wear and to improve loadcarrying properties is further augmented by addition of of 1% of tri(chloroethyl) phosphite to. a blend containing 4% of lead naphthenate and 0.2% of sulfur, the anti-wear property of the oil was materially improved while the load-carrying properties, of the oil remained at a high level. Blend No. 5 demonstrates that the ratio of sulfur to tri(chloroethyl) phosphite is too low to obtain satisfactory load-carrying characteristics.

Blendso, 7 and 8 demonstrate that other phosphoruscontaining additives were not effective in improving the wear characteristics of the oil while at the same time they detracted from the load-carrying characteristics of the oil.

The blends included in the table were made from mineral oil having the following characteristics:

Vis./2l0 F. an... 85.3 Vis./130 F. 441 Vis./l F. 1148 V.I v. 74 Pour pt., F. +10 API gravity 23.1 Percent S 1.13

The extract=P S reaction product used in some of the blends was made by reacting at about .22Q- 230 F., for fo r. hours, 1 parts by weight of phosphorus. pent sulfide and 1 part of' aromatic extract obtained from. the extraction of a neutral fraction with phenol.

The zinc salt of the eXtract=P S reaction product was made by neutralizing the extract=P S reaction product above-described with zinc oxide at a temperature of about 250 F. The extract used in making this product had the following characteristics:

Viscosity at 100 F. .SUS 165.5 Gravity APL- 17.3 Flash point Q. F 375 aaae e i Fire point F 430 Acid number .-.-:-..-1-a. -8 Sulfur percent 2.03

By blending together a haloalkyl phosphite with lead naphthenate and sulfur into a lubricating oil, a product is made which is effective both as a break-in oil for automotive gears and as a lubricant for use under ordinary service so that the break-in oil. does not have to be changed after the gears are'broken, in but can be left in the transmission without fear of causing excess wear of the gear teeth.

We claim as our invention:

1. A lubricating oil consisting essentially of a mineral Oil of l bricating oi grad a. min r amo n of. lead nap thenate, 0.05-1.0 wt. percent sulfur, 0.255.0 wt. percent of a 0 -0 haloalkyl phosphite, witha ratio of phosphite to sulfur in the range of 2 to 5:1, said phosphite enhancing the antiwear properties of the oil without detracting substantially from the an tiweld properties thereof.

2. A lubricating oil in accordance with claim 1 in which the phosphite is a tri('chlor'oa1kyl) phosphite.

3'. A lubricating oil in accordance with claim 2 in which the phosphite is tri(chloroethyl) phosphite;

4. A lubricating oil in accordance with claim 1 in which all of the haloalkyl phosphite present is in solution in the oil. i

References Cited in the file of this patent TED ST ES. T S 2 ,169,185 Shoemaker at 1. Aug. 8, 1939 ,1 ,426 Kaufman et a1- .----.---a 0% 7, 193.9 2,298,636 Prutton t t- 13, 1942 2,722,517

Claims (1)

1. A LUBRICATING OIL CONSISTING ESSENTIALLY OF A MINERAL OIL OF LUBRICATING OIL GRADE, A MINOR AMOUNT OF LEAD NAPHTHENATE, 0.05-1.0 WT. PERCENT SULFUR, 0.25-5.0 WT. PERCENT OF A C1-C30 HALOALKYL PHOSPHITE WITH A RATIO OF PHOSPHITE OF SULFUR IN THE RANGE OF 2 TO 5:1, SAID PHOSPHITE ENHANCING THE ANTIWEAR PROPERTIES OF THE OIL WITHOUT DETRACTING SUBSTANTIALLY FROM THE ANTI-WELD PROPERTIES THEREOF.