US3833500A

US3833500A - Extended service interval grease compositions

Info

Publication number: US3833500A
Application number: US00226309A
Authority: US
Inventors: C Carter; J Dreher
Original assignee: Chevron Research and Technology Co
Current assignee: Chevron USA Inc
Priority date: 1972-02-14
Filing date: 1972-02-14
Publication date: 1974-09-03
Anticipated expiration: 1991-09-03
Also published as: NL7302022A; DE2304608C2; BE794421A; CA983913A; DE2304608A1

Abstract

A GREASE COMPOSITION IS PROVIDED COMPRISING A MAJOR PORTION OF A MINERAL OIL OF LUBRICATING VISCOSITY AND EFFECTIVE AMOUNTS OF (1) AND ALKALI METAL OR ALKALINE EARTH METAL SOAP OF A FATTY ACID, (2) A N,N-DI(HYDROXY-LOWER ALKYL) SATURATED ALIHATIC CARBOXAMIDE AND (3) AT LEAST ONE ALKALI METAL SALT OF A MEDIUM-TO-LONG-CHAIN ALIPHATIC ORTHO- OR PYROROPHOSPHATE ESTER, METAL OR ALKALINE EARTH METAL SOAP IS A SOAP COMPLEX OF A MIXTURE OF A FATTY ACID AND A LOW MOLECULAR WEIGHT ALIPHATIC ACID. THE GREASES DESCRIBED HAVE SUPERIOR RUST INHIBITION PROPERTIES. THE GREASES ALSO RETAIN THEIR PENETRATION PROPERTIES WHEN CONTACTED WITH WATER AND HAVE SUPERIOR ADHESIVENESS QUALITIES.

Description

3,833,500 EXTENDED SERVICE INTERVAL GREASE COMPOSITIONS Crawford F. Carter, Pleasant Hill, and John L. Dreher,

El Cerrito, Calif., assignors to Chevron Research Company, San Francisco, Calif. No Drawing. Filed Feb. 14, 1972, Ser. No. 226,309 Int. Cl. C10m /20, 5/24 U.S. Cl. 252-18 Claims ABSTRACT OF THE DISCLOSURE A grease composition is provided comprising a major portion of a mineral oil of lubricating viscosity and effec tive amounts of (1) an alkali metal or alkaline earth metal soap of a fatty acid, (2) a N,N-di(hydroxy-lower alkyl) saturated aliphatic carboxamide and (3) at least one alkali metal salt of a medium-to-long-chain aliphatic orthoor pyrorophosphate ester. Preferably, the alkali metal or alkaline earth metal soap is a soap complex of a mixture of a fatty acid and a low molecular weight aliphatic acid. The greases described have superior rust inhibition properties. The greases also retain their penetration properties when contacted with water and have superior adhesiveness qualities.

BACKGROUND OF THE INVENTION Field of the Invention This invention concerns novel and improved grease compositions containing an alkali or alkaline earth metal soap or soap complex thickener and, more particularly, this invention concerns novel grease compositions thickened as so indicated and conatining, in addition, a combination of a carboxamide and one or more phosphate ester salts which impart improved rust inhibition, water contact stability, and adhesiveness.

With better and more improved automotive vehicles, there has been a continual desire to extend the service interval between servicing of the various lubricated parts. For the owner of the family automobile, this means greater convenience and lower cost of maintenance. For the user of commercial vehicles such as cross-country freight carriers, extended lubrication intervals (20,000 miles or more) mean more on-the-road time and a greater rate of return on the investment as well as decreased maintenance costs. However, extended lubrication intervals using available commercial greases led to driver complaints of hard steering. Also, high wear was observed on king pins, shackles, and ball and steering knuckle joints. The cause of high wear in these areas appeared to be rust, which, in turn, was believed to be caused by salt used for road deicing. This salt corrosion caused deep pitting of the metal surfaces and also plugged lubrication ducts, thus accelerating Wear due to the lack of lubrication. Currently available greases do not provide the necessary degree of rust protection of the lubricated parts for long service internal use.

In addition, current commercial greases which come in contact with water often harden and sometimes separate from the part to be lubricated. In the hardened condition, these greases do not work their way back into the part to be lubricated. Accordingly, accelerated wear occurs. Also, since the grease hardens and separates from the parts to be lubricated, it no longer seals out water, dirt and saltladened slush which cause abrasive wear and rusting. The entry of these materials into the parts also accelerates wear.

Another problem encountered with commercially available greases are that they are not work-stable. In other words, they do not stay put on the lubricated part as the 3,833,500 Patented Sept. 3, 1974 part works. The greases work off the lubricated surfaces leaving them without lubrication, thus allowing only short service intervals before the grease must be replenished. Conventional greases also tend to be displaced under shock loading conditions. Shock loading conditions to the entire steering system can occur, for example, when a wheel hits a bump or a rut or an object in the road. The sudden shock tends to force the lubricated parts together, squeezing the grease out from between them. On a commerical vehicle, another point subject to shock loading is the fifth wheel. If a severe bump is hit, shock loading can occur, displacing the grease, leading to subsequent binding of this pivot point.

Furthermore, lubrication problems can be quite perplexing for vehicles which travel interstate, particularly those which travel from north to south during the winter months When the temperature may range to or higher in the southern states and to below zero in conditions of snow, ice and salt in the northern states. A grease which will meet the requirements for extended lubrication intervals for such vehicles must not only have all the abovedescribed characteristics, but must also have appropriate high and low temperature properties. In other words, the grease should not soften and run under operating conditions encountered in the warmer climates, and yet, should retain the inclement weather characteristics described above as well as exhibit good low-temperature pumpability. Until now, such a heavy-duty grease exhibiting all these properties has not been available.

SUMMARY OF THE INVENTION It has now been found that the grease compositions of this invention exhibit most, if not all, of the properties necessary to adequately lubricate vehicles which will be operated for extended service intervals. The grease compositions of this invention comprise (a) a major portion of a mineral oil of lubricating viscosity and (b) effective amounts of (1) an alkali or alkaline earth metal soap of a fatty acid, preferably a soap complex of a mixture of a fatty acid and a low-molecular weight aliphatic acid, (2) a medium chain length saturated aliphatic-bis(hydroxy lower alkyl) carboxamide and (3) at least one and, preferably, a mixture of monoand disodium orthoand pyrophosphate medium-chain length alkyl ester salts.

DETAILED DESCRIPTION OF THE INVENTION In its broadest form, the composition of this invention is a grease having enhanced rust inhibition, water contact, wicking, and adhesive properties, comprising a major portion of a mineral oil of lubricating viscosity and eifective amounts of (1) an alkali or alkaline earth metal soap or soap complex thickener, (2), a medium chain length saturated aliphatic-bis(hydroxy lower alkyl) carboxamide and (3) at least one end, preferably, a mixture of monoand disodium salts of orthoand pyrophosphate medium-chain length alkyl esters.

The alkali and alkaline earth metal soaps used as thickeners in the grease compositions of this invention are prepared by combining a fatty acid or lower alkyl ester thereof with an alkali or alkaline earth metal hydroxide or carbonate. The preferred thickeners are soap complexes prepared by combining a fatty acid or lower alkyl ester thereof, a low-molecular weight aliphatic acid, an alkali or alkaline earth metal hydroxide and an alkali or alkaline earth metal carbonate. Alternatively, a larger quantity of the hydroxide can be carbonated in situ with carbon dioxode or urea after being combined with the acids.

The soap complex is not susceptible of description by general formula and may only be described according to its method of preparation, which is generally well known in the art. The soap complex is prepared by combining the fatty acid generally in the form of a lower-alkyl ester with the lubricating Oil and adding thereto the hydroxide at an elevated temperature with mixing until a uniform blend is obtained. Subsequently, the low-molecular weight aliphatic acid is added, followed by the addition of the carbon dioxide or urea.

Fatty acids useful in the preparation of the thickeners of the grease compositions of this invention can contain from to 30 carbon atoms, preferably from about 16 to about 20 carbon atoms. Stearic acid and derivatives thereof, such as 12-hydroxy stearic acid, are particularly preferred as the fatty acid.

In the preparation of the grease, the fatty acid can be used as the free acid or as a lower alkyl ester thereof. The lower alkyl alcohol from which the ester is prepared can contain from 1 to 4 carbon atoms, e.g., methanol, ethanol, propanol, isopropanol, butanol, isobutanol, and the like. For convenience in handling, availability and economics, methanol is generally the preferred choice.

Suitable low molecular weight acids include saturated and unsaturated aliphatic mono-carboxylic acids having from about 1 to 6 carbon atoms, such as formic, acetic, propionic, furoic, acrylic and similar acids including their hydroxy derivatives such as lactic acid. Formic and, particularly, acetic acid are preferred acids in the preparation of the thickeners used in the grease compositions of this invention.

When a soap complex is prepared, the mole ratio of the low molecular weight aliphatic acid to the fatty acid can vary over a wide range from about 2 to about 40 moles of the low molecular weight acid per mole of the fatty acid.

The choice of the metal component depends to a certain extent on the use for which the grease is intended. Metal components include the alkali metals and alkaline earth metals found in Groups IA and HA of the Periodic Table of Elements. Useful alkali metals include lithium, sodium and potassium. Particularly preferred of the alkali metals is lithium. Useful alkaline earth metals include magnesium, calcium and barium. Of the alkaline earth metals, calcium is preferred. Other metals useful in the invention include the heavy metals of Groups HE and IVA of the Periodic System, for example, zinc and lead which may be used either alone or in combination with the metals referred to above. Generally, the latter metals are included in minor amounts to convey special properties to the grease compositions.

Grease compositions containing alkaline earth metal soap complex thickeners and processes for preparing such greases are described in Morway et al., US. Pat. No. 2,846,392, issued Aug. 5, 1958, and Dreher, US. Pat. No. 3,186,944, issued June 1, 1965. The disclosure of these patents is incorporated herein by reference.

The medium chain length saturated aliphatic-bis(hydroxy lower alkyl) carboxamide preferably has the formula:

Ra-OH wherein R represents a saturated aliphatic group of from 9 to 21 carbon atoms, and preferably from 11 to 19 carbon atoms, for example, nonanyl decyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, heneicosyl. These saturated aliphatic moieties generally represent the aliphatic portion of fatty acids and hydrogenated fish acids. The group represented by R can also contain minor amounts, preferably less than 1 percent, of groups having one or more points of unsaturation, such as a group derived from oleic acid. Generally, R will represent a mixture of saturated aliphatic groups comprising, for example, to 30 percent of a tridecyl group, 25 to 40 percent of a pentadecyl group, 20 to 30 percent of a heptadecyl group and from .5 to 7 mole percent of other groups containing between 11 and 19 carbon atoms.

In the above Formula I, R and R each represent a lower alkylene group of from 1 to 4 carbon atoms, e.g., methylene, ethylene, propylene, isopropylene, butylene, isobutylene, and the like. R and R can be the same or can be different, preferably R and R are the same and represent ethylene.

Phosphate ester salts useful in the grease compositions of this invention include those represented by the following formulas:

In the above Formulas II and III, R; and R each represent a saturated aliphatic group of from 8 to 17 carbon atoms, e.g., octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl and the like. The aliphatic group can be straight chain or branched chain and preferably is branched chain. The groups can be de rived from oligorners of olefins such as propylene and butylene. For example, R and R can represent saturated aliphatic groups derived from triand tetrapropylene, di-, tri-, and tetraisobutylene. Preferably, R and R each represent the hydrocarbyl portion of a primary oxo alcohol of an oligomer of propylene or butylene. More preferably, R and R each represent the hydrocarbyl portion of a primary oxo alcohol derived from triisobutene.

The oxo reaction is well known to those skilled in preparing derivatives of olefins. Briefly, it comprises contacting an olefin with carbon monoxide and hydrogen in the presence of a catalyst such as cobalt. Addition across the double bond yields an aldehyde, part of which is reduced by the hydrogen in the presence of the cobalt catalyst to the primary alcohol. This mixed product is then completely reduced to the alcohol with hydrogen in the presence of a catalyst. This alcohol contains one more carbon atom than the starting olefin.

Since the alcohols are produced from polymers of the olefin monomer, the polymers are generally a mixture of isomers. Furthermore, the addition across the double bond can occur at either carbon atom (except when one carbon atom has only carbon to carbon bonds) a more complex mixture of compounds is obtained. However, since an aldehyde is always produced as the first step in the preparation of the alcohol, only primary alcohols are obtained.

In the above Formula II, a and b each represent 1 or 2 such that the sum of a and b equals 3.

The mono and disodium salt of the ortho and pyrophosphate esters are present in the grease composition 1n a mixture of the three types of compounds represented by Formulas II and III. Typical mixtures of the phosphate ester salts contain from about 20 to 45 weight percent of the phosphate ester salts of Formula II wherein a represents 1 and b represents 2, about 40 to about 65 weight percent of a phosphate ester salts of Formula II wherein a represents 2 and b represents 1 and about 5 to about %I0I weight percent of a phosphate ester salts of Formula Examples of similar ortho phosphates and methods of preparing these compounds are shown in Ernst et al., US. Pat. No. 2,656,372, issued Oct. 20, 1953.

While not wishing to be bound by such statements, it is believed that some type of complexing and/or chemical bond formation occurs between the phosphate ester salts and the carboxamide when these two additives are combmed with a small amount of diluent oil to prepare a concentrate for addition to the grease compositioni Excellent grease compositions are obtained when these additives are added to the thickened grease composition in this previously combined form and this is the preferred method of preparing the grease compositions of this invention.

The Lubricating Mineral Oil A mineral oil of lubricating viscosity is present as the major portion of the composition of this invention. Preferably, it comprises at least 55 weight percent of the total composition and more preferably comprises about 65 weight percent. It will not, however, comprise more than about 95 weight percent of the total composition. The mineral oil base can be a single oil or it can be a mixture of oils. The oil should have a viscosity within the range of about 35 to 200 SUS at 210 F., a viscosity index of 100 or higher may be employed. However, oils of lower viscosity index, such as below 60, generally require less thickener in the grease for a given consistency.

The oils may be naphthenic base, paraflin base and mixed base oils derived from petroleum, including lubricating oils derived from coal products. A particularly useful base oil comprises about 40 to 60 percent of a solvent refined neutral mid-continent oil having a viscosity of 480 SUS at 100 F. and 60 SUS at 210 F., 30 to 40 percent of a naphthenic base mineral pale oil having a viscosity of about 1800 SUS at 100 F. and about 85 SUS at 210 F., and about to percent of a heavy bright oil having a viscosity of 5,000 SUS at 100 F. and 210 SUS at 210 F.

The Grease Composition The grease composition normally will contain from about 20 to about weight percent of the soap complex thickener and from about 1 to about 5, and preferably about 2 to about 4, weight percent of each of the carboxamide and the phosphate ester salts.

Various other additives may be incorporated into the grease composition of this invention, subject only to the requirement that they are compatible with the required components of the invention and with each other. Typical additives which may be incorporated include rust inhibitors (both water and oil soluble types) oxidation inhibitors, stringiness agents, dyes and other color additives, dispersants, anti-Wear agents and the like. Rust inhibitors include, in addition to the carboxymide and phosphate ester salts mixture described above, alkali metal nitrites, such as sodium and potassium nitrite, stringiness agents include for example rubber latex; coloring materials includes a wide range of organic dyes both naturally occurring and synthetic, as well as such materials as carbon black. Dispersants are included in the grease to help better disperse the thickener throughout the oil base. Ap propriately chosen dispersants often increase the effectiveness of the thickener and a particularly useful group of dispersants are alkyl methacrylate-vinylpyrrolidine copolymers. These polymers are available commercially from a number of suppliers. For example, a number of polymers available from Rohm and Haas under the trade name Acryloid in the 900 series, such as 909, 917, 950, 9668 and the like, have found particular utility as dis persants in the grease composition of this invention. A variety of antiwear agents are available for inclusion in the grease composition. A preferred antiwear agent is molybdenum disulfide.

The optional additives for the grease composition of this invention generally will be present in amounts not exceeding 3 weight percent. For additives such as the stringiness agent and the coloring agent, the amounts will often not exceed 0.1 weight percent.

The inclusion of the carboxamide-phosphate ester salts mixture confers excellent rust inhibition properties to the grease composition. In addition, the carboxamide phosphate ester salts combination enhances the thickening obtained with the soap complex and improves the adhesiveness of the grease composition obtained. In other words, the grease composition stays in place on the part to which it is applied.

In addition, the inclusion of the carboxamide-phosphate ester salts combination improves the water stability of the grease composition. Greases identical in composition except for the omission of the carboxamide-phosphate ester salts combination, generally harden to some degree upon coming into intimate contact with water. Upon being worked, the grease compositions will soften somewhat, but in most cases do not soften to the penetration value observed prior to being contacted with water.

By contrast, the grease compositions of this invention, which include the carboxamide-phosphate ester salts combination generally harden much less upon contact with water than those not containing the combnation. In addition, upon being worked, the greases soften to approximately the penetration value observed prior to being contacted with water. In some cases, even higher penetration values may be observed. Thus, inclusion of the carboxamide-phosphate ester salts combination in the grease compositions presents definite advantages.

Good water contact properties are important because the harder greases can separate from the lubricated part or if the grease is somehow forced from the lubricated part it will not work itself back into the part. In either event, not only will lubrication of the part be lost, but also the part will no longer be sealed against the elements, such as rain, snow, salty slush, and the like. The corrosion and rust protection normally provided by the grease will be lost and failure of the lubricated part will be greatly accelerated.

The grease compositions of the invention can be prepared by methods well known to those skilled in the art. Briefly, a general procedure which has been found to provide satisfactory results in the preparation of the soap complex greases involves blending the fatty acid with the base oil and heating the blend to a temperature at which good dispersion of the acid in the oil is obtained. Subsequently, the alkali or alkaline earth metal is added for example in the form of a hydroxide generally in large excess of the fatty acid, and the entire mixture is stirred at the elevated temperature to obtain a uniform dispersion of the resulting soap in the oil. The mixture is further heated, for example, to about F. after which the lower molecular weight aliphatic acid is slowly added. The entire mixture is then stirred for a sufiicient time to obtain a smooth dispersion, after which the carbon dioxide or urea is added. Generally, the mixture is then heated under pressure to a higher temperature, for example, about 300-320" F. The pressure range is not critical but is used to force the carbon dioxide to dissolve in the oil and when urea is used, can be maintained by bleeding ammonia from the reaction vessel during the conversion of the urea. Subsequent to this, usually during cooling of the composition the carboxamide-phosphate ester salts combination, as well as the optional additives, are blended into the grease by well-known methods.

The greases of this invention are particularly useful for lubricating all parts of heavy-duty trucks, particularly where extended lubrication intervals are desired in wet and corrosive environments. These greases exhibit good low temperature pumpability when prepared as NLGI No. 2 grade greases. The apparent viscosity (resistance to flow while being pumped) is generally as low or lower than Grade 1 greases. This means that the grease is readily handled and pumped in cold weather, but has the service retention and performance of Grade 2 greases. Accordingly, they do not deteriorate when in service in the warmer climates and during hot summers. The resistance to summer heat combined with the protection provided against wet weather conditions means that the grease compositions of this invention are all-weather, all-season lubricants.

The greases of the invention are further illustrated in the following examples. In these examples all composition quantities are set forth as parts by weight.

EXAMPLES Example 1 A grease was formulated by thickening 64.4 parts of a lubricating oil mixture comprising 32 parts of a solvent refined neutral oil having a viscosity of 480 SUS at 100 F. and 60 SUS at 210 F., 23.3 parts of a naphthenic base mineral pale oil having a viscosity of 1800 SUS at 100 F. and 85 SUS at 210 F. and 9.1 parts of a heavy bright oil having a viscosity of 5000 SUS at 100 F. and 210 SUS at 210 F. The thickener was prepared by reacting in situ 6 parts of methyI-IZ-hydroxystearate and 12.5 parts of hydrated lime at about 130 F. with agitation until a uniform blend was obtained. The temperature of the reaction mixture was raised to about 180 F. and after about 0.5 hours, 3.7 parts of glacial acetic acid were added slowly during the next 0.75 hours. The reaction vessel was then pressurized with carbon dioxide and 4.3 parts of CO were added while the temperature was raised to about 320 F. This temperature was maintained for about one hour after which the vessel was depressurized. The grease is dehydrated by allowing the water of reaction to boil off but can be accelerated by drawing a moderate vacuum on the reaction vessel. During cooling, 5 parts of a pale oil solution comprising about 35 Weight percent of a C C saturated aliphatic bis(hydroxyethyl)carboxamide and about 31 weight percent of a mixture of sodium salts of tridecyl phosphate esters (about 35 percent of Formula I wherein a=l and b=2, about 53 percent of Formula I wherein a=2 and b=1, and about 12 percent of Formula II) is blended in. Also added are rust and oxidation inhibitors, a dispersant and antiwear, stringiness and coloring agents in amounts ranging from 0.01 to 4 parts such that the total number of parts added to prepare the grease composition equal 100. If necessary, further blending can be accomplished by passing the grease through a stator-rotor mill. Subsequently, the grease was worked 60 strokes in accordance with ASTM Method D-217.

The grease so obtained had a worked penetration of about 295, was easily pumpable and displayed excellent adhesiveness, water contact, rust inhibition and wicking properties. The latter three properties are further illustrated below.

Example 2 In a manner similar to that of Example 1, a lithium soap thickened grease is prepared by reacting in situ in a mixed naphthenic-paraffinic base oil (viscosity of S00 SUS at 100 F. and viscosity index of 65) lithium hydroxide and methyl-12-hydroxystearate. Acetic acid and carbon dioxide are omitted from the thickener preparation. During cooling, the same carboxamide phosphate ester salts mixture as used in Example 1 in the same proportions and polar and non-polar oxidation and rust inhibitors are added to the grease which is then blended and subsequently worked to obtain a worked penetration of about 310. This grease also displays the advantages discussed for the calcius complex soap described in Example 1.

Example 3 To a calcium salt-soap complex grease of the type available under the trade name Nebula from the operating companies of Standard Oil Company of New Jersey containing a naphthenic-paraffinic base oil and prepared generally according to the disclosure of US. Pat. 2,846,392 is added the same carboxamide-phosphate ester salts mixture used in Example 1 in the same proportion which is then blended and worked to obtain a worked penetration of about 325. This grease also displays the advantages discussed for the calcium complex soap grease described in Example 1.

:Rusting' Test The grease of Example 1 was tested for rust inhibition according to the ASTM D-l743 test and the EMCO R rusting test.

In the ASTM test a weighed amount of grease is applied to a roller-type wheel bearing which is then run for a short period to distribute the grease as it would be in actual service. The bearing is then submerged in water for a few seconds followed by storage in a sealed container at percent relative humidity. To accelerate this test, additional runs were made adding 1 and 5 percent synthetic sea water to the distilled water used in the submerging step. At the end of two Weeks the bearings were rated for rust on a scale of 0 to 5 '(O=no rust; 5=very rusty). The results are shown in Table I below.

The EMCOR test uses a cycling procedure and double row ball bearings. A Weighed amount of grease is applied to the bearing which is assembled on a plastic shaft and inserted in a non-rusting housing of identified design to the standard bearing pillow block. The bearing is run for several minutes to distribute the grease. Then a small amount of water is added and the bearing is operated through three cycles of running and standing for three days, at the end of which the bearing is allowed to stand idle for four and one-half days before being rated for rust. To accelerate the tests, additional runs were made in which 3 and 5 percent synthetic sea water was added to the distilled water added to the bearing. The same rating scale is used as described for the ASTM test. The results are shown in Table I below.

TABLE I.RUSTIN G TEST 1 The grease prepared in Example 1. 2 fIhe grease prepared in Example 1, except not containing the carboxamide and phosphate ester salts.

As can be seen from the above results, those greases not containing the mixture of carboxamide and phosphate ester salts rusted except in the presence of distilled water, while the greases containing the carboxamide-phosphate ester salts mixture showed only a trace of rust even under the most corrosive conditions of the test.

Wicking Test This test determines the rapidity with which the lubrieating oil is drawn from the grease composition by oil absorbing materials. This test indicates the performance of the grease under dusty service conditions where the lubricated parts are not sealed from the surrounding environment. The grease is generally applied to the lubricated parts until it exudes therefrom. Dust from the service environment sticks to the exposed grease and absorbs the oil. If the grease displays poor antiwicking properties, the oil from the grease within the lubricated part will be drawn out in much the same manner that kerosene flows in the wick of a kerosene lamp. The greater the wicking displayed by the grease, the faster the oil will be removed and the sooner the parts will need re-greasing. Thus, any appreciable amount of wicking markedly reduces the service interval between relubrications. In this test a small roughly spherical quantity of grease is placed in the center of a piece of circular filter paper (generally about 4-inch diameter) which rests on a non-absorbing support such as glass. After the grease has been on the filter paper for a predetermined length of time (generally about 24 hours) the diameter of the oil-soaked portion of the paper is measured. The results of testing the TABLE II.WICKING TEST Diameter of oil saturated paper, inches With Without carboxcarboxamide amide and and phosphate phosphate ester ester Grease of ex salt salt 1 it a 1 a 21 M c 21 M a In all cases the grease containing the mixture of carboxamide and phosphate ester salts displayed much better antiwicking properties than the greases without these additives.

Water Contact Test During service, greases often come in contact with water. This test determines how much greases harden when contacted with water. In this test a grease is prepared as described in Examples 1-3. The penetration value of the grease is then determined. Twenty-five weight percent water is added to a sample of the grease and mixed until a uniform blend is obtained. The mixture is allowed to stand 24 hours before the unworked penetration is determined. The sample is then worked for 60 strokes according to ASTM Method D-217 and the penetration is measured. The results of testing the greases prepared in Examples 1-3 both with and without the mixture of carboxamide and phosphate esters are shown in Table III.

TABLE TIL-WATER CONT ACT TEST Grease plus 25%w of H20 1 Grease without carboxamide and phosphate ester salts.

In all cases, the grease without the carboxamide and phosphate ester salts was much harder than the same grease containing these additives subsequent to being con- .tacted with water. With all three types of grease the worked penetration of the grease to which water had been added closely approximated that value obtained before any water was added when the grease contained the carboxamide and phosphate ester salts. When the greases did not contain these additives, the calcium based greases became much harder while the lithium based grease remained relatively unchanged.

The above tests demonstrate the superior properties of the greases of the invention which contain the mixture of the carboxamide and phosphate ester salts.

While the invention has been described herein with particularity and with reference to specific embodiments, it will be appreciated that many variations can be effected within the spirit and scope of the above description and appended claims.

We claim:

1. A grease composition comprising (A) a major portion of a mineral oil of lubricating viscosity,

(B) 20-30 weight percent of an alkali metal or alkaline earth metal soap of a fatty acid containing 10-30 carbon atoms,

(C) 1-5 weight percent of a carboxamide of the formula:

O Rz-OH Rs-OH (D) 1-5 weight percent of a phosphate ester salt selected from those having the formulae:

and mixtures thereof, wherein (1) R represents a saturated aliphatic group of from 9 to 21 carbon atoms, (2) R and R each represent a lower alkyl group of from 1 to 4 carbon atoms, (3) R and R each represent a saturated aliphatic group of from 8 to 17 carbon atoms, and (4) a and b each represent 1 or 2 such that the sum of a and b equals 3.

2. A grease composition of Claim 1, wherein (1) R represents a saturated aliphatic group of from 12 to 18 carbon atoms,

(2) R and R each represent a lower alkyl group of from 2 to 3 carbon atoms, and

(3) said fatty acid contains from 10 to 22 carbon atoms.

3. A grease composition comprising (A) a major portion of a mineral oil of lubricating viscosity,

(B) 20-30 weight percent of an alkali metal or alkaline earth metal soap complex of a mixture of a fatty acid containing 10-30 carbon atoms and a low molecular weight aliphatic acid containing 1-6 carbon atoms,

(C) 15 weight percent of a carboxamide of the formula R1(I1N/ \R3OH (D) 1-5 weight percent of a phosphate ester salt selected from those having the formulae:

II o

0 I it. and mixtures thereof, wherein:

(1) R represents a saturated aliphatic group of from 9 to 21 carbon atoms, (2) R and R each represent a lower alkyl group of from 1 to 4 carbon atoms, 3) R and R each represent a saturated aliphatic group of from 8 to 17 carbon atoms, and (4) a and b each represent 1 or 2 such that the sum of a and b equals 3. 4. A grease composition of Claim 3, wherein (1) R represents a saturated aliphatic group of from 12 to 18 carbon atoms, (2) R and R each represent a lower alkyl group of from 2 to 3 carbon atoms, and (3) said fatty acid contains from 10 to 22 carbon atoms. 5. A grease composition of Claim 4 which contains 1 to 3 weight percent of a polymeric dispersant, 0.5 to 1.5

weight percent of an inorganic rust inhibitor, 0.5 to 1.5 weight percent of an antiwear agent and 0.01 to 0.1 weight of a stringiness agent.

6. A grease composition of Claim 5, wherein said polymeric dispersant is an alkyl methacrylate-vinylpyrrolidine copolymer, said rust inhibitor is an alkali metal nitrite, said antiwear agent is molybdenum disulfide, and said stringiness agent is a rubber-latex.

7. A grease composition of Claim 6, wherein said carboxamide and said phosphate ester salts are derived from an oil based concentrate containing both said carboxamide and said phosphate ester salts.

8. A grease composition of Claim 7, wherein the groups R O and R O are derived from a primary oxo alcohol prepared from triisobutylene.

9. A grease composition of Claim 8 containing about 0.3 to 0.7 weight percent of a phosphate ester salt of Formula II wherein a represents 1 and b represents 2; about 0.6 to about 1.0 weight percent of a phosphate ester salt of Formula II wherein a represents 2 and b represents 1; and about 0.1 to 0.3 weight percent of a phosphate ester salt of Formula III.

12 '10. A grease composition of Claim 9 wherein said fatty acid is 12-hydroxy stearic acid and said low molecular weight aliphatic acid is acetic acid.

References Cited UNITED STATES PATENTS DANIEL E. WYMAN, Primary Examiner I. VAUGHN, Assistant Examiner US. Cl. X.R.