US3390085A - Grease composition - Google Patents

Description

United States Patent I ABSTRACT OF THE DISCLOSURE This application discloses a grease containing an imid- *azoline, sa'lt made by reacting a fatty acid having from 6 to 18 carbon atoms with an imidazoline selected from the group-consisting of where n is an integerof from 1 to 4,.R and R are selected from the group consisting of hydrogen and an aliphatic hydrocarbon having from to 17 carbon atoms,

properties so that it can beused under moist conditions with high effectiveness. t i

It is also an object of the present invention to provide a grease having'excellent rust inhibiting properties which is resistant to thixotropic hardening. Other objects and a more complete understanding of my'present invention will-become apparent fro'm'the following description of the invention taken in conjunction with the appended claims; The base oil and thickening agent 'utilizedin the grease I composition of my present invention are of the conventional type. For example, pale oils, mid-continent solvent treated paraffin base oils, western solvent treated, or western refined naphthenic oils, refined PennsylvaniaJOO percent parafiin oils, or mixtures-thereof, may be utilized as base oils. The thickening agent utilized in I my present 1 grease composition may be a soap made from a monoat a reaction temperature of between about 160 and 220 R, which additive serves asa rust inhibitor which does not impair the mechanical stability, dropping point, water tolerance or thixotropic hardening resistance of the base grease.

This is a continuation-in-part of application Ser. No. 147,486 filed Oct. 25, 1961 and now abandoned.

This'jinvention relates to a grease composition and more particularly relates to. a grease composition having exceptional rust inhibiting properties together with good physical properties.

A grease suitable for a wide variety of operating conditions must have rust inhibiting properties since greases, when contacted with moisture or water, will either absorb water or reject the water and in either case the metal parts being lubricated by the grease will be subject to the rust: ing action of water. It has been found in the past, however, that various rust inhibiting additives, in addition to differing greatly in their effectiveness to prevent rust formation, also tend to impair the physical properties of the grease. For example, some we'll-known rust inhibitors have been found, when added to the grease, to reduce the mechanical stability, lower the droppingpoint and pos sibly cause a high degree of thixotropic hardening in the grease. The present invention, therefore, is directed to a new grease composition having outstanding rust inhibiting properties which at the same time preserves the mechanical stability, the dropping point and the ability to resist thixotropic hardening ofthe grease.

It has now been discovered that a grease of outstanding rust inhibition properties, together with good physical properties, can be formed with. one or more of several soap-thickening agents when the reaction product of a substituted imid-azoline and certain fatty acids is incorporated in the grease composition.

Accordingly, it isa primary object of the present invention to provide a grease having the ability to inhibit the rusting of metal surfaces in the presence of water.

It is also an object of the present invention to-provide a grease having-excellent rust inhibiting properties'and which does not impair the mechanical stability or dropping point of thegrease.

"Another object of my present invention is to provide a grease composition having excellent water absorption carboxylic acid having from about 14 to about 22 carbon atoms per molecule, for exa'mple,-lauric, myristic, palmitic, oleic, stearic, hydroxystearic, 12-hydroxystearic methyl esters of 12-hydroxystearic acid, ethyl hexoic, behenic, etc. or their glycerides, or fattymate-rials containing such acids or their glyeerides. The fatty materialscan be vegetable, marine and animal fatty oils and hydrogenated products thereof-within the above description. Hydrogenated castor oil, tallow, tallow fatty acids, cotton seed oil, stearin, hydrogenated fish-toils, are examples of suitable fatty oils. The metal component of the soap may be an alkali or alkaline earth-metal such as lithium, calcium, sodium, barium, or mixtures thereof; The preferred soap thickening agents, however are lithium 12-hydroxystearate, lithium stearate, calcium stearate and lithium, calcium and barium soaps of C through C monocarboxylic acids or their glycerides. The amount of soap present in the grease of my present invention ranges from about 5 to 25 percent of the grease by weight, preferably about 7 to 14 percent by weight.

The greases of my present invention may be prepared by any conventional process, however, preferably the soaps are prepared in situ in the presence of at least a portion of the total oil, preferably about 10 percent of the total oil. Maximum temperatures of about 230 to 425 F. may be used with a maximum processing temperature of about 230 to 350 F. being preferred to .form the proper physical characteristics of the soap fibril. Complete saponification usually takes place in about 15 to 20 minutes after maximum temperature is obtained. For example, the fatty materials and starting oilrnay be heated in a kettle until a substantially complete solution is formed. A hot slurry of a metal hydroxide such as lithium hydroxide or calcium hydroxide may then be added to the kettle and the mixture agitated vigorously While the mixture is heated slowly to, evaporate water. During the saponification and the hydration further quantities of the starting oil may be added to limit foaming and maintain the mixture in at least a semi-fluid state. After the water of reaction and the water in which the hydroxide was dissolved is eliminated, by evaporation, it is advantageous to raise the temperature of the mixture to about 230 to 350 F. for a period of about 1 to 2 hours. At the end of this period the grease is allowed to cool and cooling may be facilitated by the further addition of base oil. The grease additives such as oxidation inhibitors and rust inhibitors may then be added and the grease milled in the usual manner,'for instance in a colloid mill, with a clearance of about .0011 to .005.

The reaction products utilized in my new grease primarily as a rust inhibitor are imidazoline salts: and may I Patented June 1 968 :i "j V 3399985 are.,suitab l,e. acid .materials to produce the desired reac-..

tion product. The imidazolines useful for making the additives of my present invention are substituted imidazolines formed by the reaction of a fatty acid and a polyamine, for example the ethylene polyamines, such as ethylene diamine, di-ethylene triamine, di-ethylene tetramine, tetraethylene penta-mine, and, the ethylene. ,diamine, at about 500 to 570 F.

. The imidazolines used to produce the salt which is used in my new greaseare of a cyclic tertiary amine type, eitherthe mono-amine or the di-amine. Thus the type of imidazolines useful in my present invention are of the type shown-by the following formulae:

I and N l N J JHmNHi JHzMOH I t which are respectively l-(2-a-mino ethyl)-2- alkyl-2-imidazoline and 1-(2-hydroxy ethyl)-2-n-alkyl-2-irnidazoline, and 'l-alkyl 2-n-alkyl-2-imidazoline, where n is an integer of 'from'I to 4; -R is either hydrogen or an alkyl substituent comprising an aliphatic hydrocarbon having from about 5 to 17 carbon atoms, such as, for example, pentyl, nonyl, tridecyl, heptadecenyl, hendecenyl, heptadecyl, heptadecenyl, heptadecadienyl, coco, pentadecenyl, etc., derived from relatively long-chain fatty acid materials, such as oleic and tall oil fatty acids, etc.

Although my invention should not be limited thereto since the exact reaction product is a mixture of several components, it is believed that the reaction product in the case of the amine substituted imidazoline is as foland in the case of the hydroxylated imidazoline is as follows: v

' The latter compound is available commercially as NalcaminesG-11 from the Nalco Chemical Company. The amine substituted imidazoline is available commercially as Nalcamines G-39M from Nalco Chemical Company, and-as Cationic N-FD available from the Leyda Oil and Chemical Company of Hawthorne, Calif.

Due to the nature of the rust additive imidazoline salts of this invention, they may be best defined in terms of their manner of production. At temperatures higher than specified and reaction times longer than specified will react with the formation of imidazoline amides rather than the imidazoline salts. The amides have been found to be unpredictable as rust inhibitors and most of those tested have failed totally. This process comprises mixing at least one of the imidazolines where n is an integer of at least 1, and R and R are either hydrogen or an aliphatic hydrocarbon having from 5 to 17 carbon atoms, with a fatty acid having from 6 to 18 carbon atoms at a temperature of less than about 275 F., the temperature at which water immediately begins to be driven off dehydrating the salts to amides. Preferably, the reaction temperature is maintained at between 1-60 and 220 F. to react the imidazoline and acid to form 4 salts .without. formation of imidazoline amides by expulsion of water.

The time for the reaction is dependent upon the temperature of the reaction. Generally, the reaction requires /2 /2hour at 150 F. andabout A /s hour at 270 F. The temperature and timemay be varied by observing the reactants and adjusting the temperature and reaction time to prevent the expulsion of water. The reaction product is then cooled to room temperature and added to'the grease compositions of my invention.

It was found that the imidazoline salt additive of my present invention is effective only in grease compositions having an excess alkalinity, preferably about 0.02 to 0.14

percent by weight excess metal hydroxide. (See the data. on the greasesshown in Examples 5, 7, 17, 18-20, 22, and 23.) The grease shown in Examples 6 and 17 contained excess oleic acid and failed the rust tests with my present additive, whereas with other additives, acid greases may pass the rust test.

The invention will be described further in conjunction with the following specific examples. It should be under- "stood that the invention is not to be limited by the details disclosed in the examples. All the percentages given in the specification and the examples are by weight unless otherwise indicated.

Example 1 Two mols of caprylic acid were mixed with one mol of Nalcamine G-39M at room temperature in a beaker. The exothermic reaction of the mixture raised the temperature of the mixture to about 200 F. without the expulsion of water. The reaction product was believed to he a mixture of where R is predominately a heptadecenyl group, and R is a heptyl group.

Example 2 Example 3 The reaction of Example 1 was repeated, using 2 mols of oleic acid reacted with the imidazoline.

Example 4 The reaction of Example 1 was repeated, using 1 mole of caprylic acid and 1 molof Nalcamine G-11, identi- G-39M 1-(2-aminoethyl)-2-n-alkyl-2-imidazo1ine is made by reacting tall oil with diethylene triamine at 550 600. F- and has the general formula I N C H:

II 3-0 H,

and the following typical analysis Apparent molecular weight Apparent combining weight Percent imidazol I Percent titratables Specific gravity at 60 F a 0.948 Pour point, Viscosity at 60 F. cps. Density1bs./gal 91 tied as 1-(Z-hydroxyethyl)-2-n-coco-2-irnidazoline and having the general formula:

Example 5 r 117 grams of a mineral lubricating oil having a viscosity of about 50 to 100 SUS at 210 F., 73.85 grams of hydrogenated castor oil, and about 4.08 grams of Neofat 16-54 (a eutectic mixture containing 68 percentpalmitic acid, percent of stearic acid and 2 percent oleic acidproduced commercially by the Armour Company) were added to a kettle and heated while agitating the mixture until solution was complete. The temperature was about 190 F. A hot aqueous solution of lithium hydroxide monohydrate (13.1 grams of lithium hydroxide in 53 grams of water) was added to the mixture and the temperature gradually raised and about 400 grams of base oil added.

During saponification as the temperature passed 212 F., evaporation of the water was effected. The saponification was complete and the grease mass substantially completely dehydrated in about 1 hour and 20 minutes at a temperature of 340 F. The temperature was maintained at 340 F. for about minutes. The grease was cooled and oil added to a total of 911.12 grams and 4.96 grams of Ortholeum 300 (diphenyl amine oxidation inhibitor from duPont) and 7.50 grams of the reaction product of Example 1 added to the mass before colloidally milling the greases in a Charlotte Colloid Mill. at .001 inch clearance. The resulting grease was then tested, the sig nificant results of which are included in Table I.

TABLE I Grams Wt. percent Composition:

Lithium-Castorwax soap 72. 25 7. 225 Lithium-Neofat 16-54 soap.. 4. 17 0. 417 Base Oil 911.12 91.112 Ortholeum 300... 4. 96 0. 496 Reaction product of Rust In 7. 0.750 ample 1.

. 1, 000. 00 100.000 Inspection 'iestsz.

Unworked Penetration at 77 F 364. ASTM Penetration at 77 F 358 Shell Roll Test-Penetration at 77 F. scale converted):

hour 356. r i 24 hours 70.

Alkalinity as Li (OH)--. 0.038% by wt. ASIM Dropping Point 386 F. 1 Copper Corrosion, 24 hours at 77 Neg. ASTM D 1743'I Rust 'Iests.. Pass. Additive Solubility Excellent. Water Absorption 100%. Penetration at 77 F. after Water absorp- 386.

tion.

- 1 4.5 lbs. drop 100 hours. NorniaHofiman without cataiyst.. lbs. drop 500 hours- Example 6 rust test.

TABLE II Grams Wt. percent Compounding Materials:

LithiumCastorwax Soap Neofat-16-54 (Armour) Ortholeum 300 Reaction product of Exampl Composition: 1

LithiumCastorwax Soap Lithium-Neoiat 16-54 soap. Base Oil Ortholeum 300 Reaction product of Example 1 Inspection Tests: Penetration at 77 F. unworked 367,

ASTM Penetration Worked Penetration 5,000 strokes.. Worked Penetration 10,000 strokes. Worked Penetration 100,000 strokes. 389. Penetration change 100,000 strokes +26. Shell Roll Test:

Penetration 1 hour 367. Penetration 24 hours 402. AAR Bleeding Test, 15.4% total bleed... 3.4% evaporation. Acidity as oleic 0.21% by wt. ASIM Dropping Point 385 F. Copper Corrosion, 24 hours at 77 F- AS'IM D 1743-60T Rust Test w Neg.

Failed.

Example 7 A grease made according to the procedure of Example 5 was tested for thixotropic hardening and the results tabulated in Table III.

TABLE III Grams Wt. percent Compounding Materials:

Castorwax 464. 0 6. 6444 Neofat 16-54 (Armour).. :25. 1 0. 3594 Li (OH) H2O-...... 75. 8 1. 0854 Water 303. 0 4. 3889 Base 011.... 6, 033.0' 86. 3913 Ortholeurn 3 32. 98 0. 4723 Reaction product of Example 1 49. 46 0. 7083 Composition:

Lithium -Castorwax soap (464 0.978 453.98 6. 88 Lithium-Neoiat 16-54 soap (25.1 x i 91. 48 Ortholeurn 300 32. 98 0. 50 Reaction product of Example 1. 49. 46 0.

. 6, 595. 07 100. 00 Inspection Tests:

Penetration at 77 F. Unworked-........ 375. Penetration AS'IM 366. Worked Penetration 5000 strokes-. 369. Worked Penetration 10,000 strokes-- 363. lVorked Penetration 100,000 strokes. 360. Penetration change 100,000 strokes 6. Shell Roll Test-Penatration at 77 F.

(% Zcale converted):

y 850 sec. Pressure V1scos1tyApparent SUS Viscosity 850 secat- 30 F 824,810 -20 F. 616,037. -10 F. 370,000. 0 F. 189,010. 20 F. 000. 80 F.-- 5, 934. F-. 3,650.

0 F 1,122. w Alkalinity as Li 0 0.021% by wt. ASTM Dropping Point 382 F.

Thixotropic Hardening Test .scale converted):

Worked 60 strokes 369.

TABLE IV Grams Wt. Percent Formulation:

Grease, unmilled, uninhibited 892.86 89. 286 Base Oil 09.10 9.010 ortholeum 300 0. 54 0. 054 Reaction product of Example 2 7. 50 0.750

Composition:

Lithium-Castorwax soap (892. 86 x .0795) 70. 98 7. l0 Lithium-Neofat 16-54 soap (89 6 x .0045 4. 02 0. 40 Base Oil (892.86 x .9l10)+99.l0= 912. 50 91. 25 Ortholeum 300 (892.86 x 005)+0.54 '5. 00 0.50 Reaction product of Example 2. 7. 50 0. 75

- Inspection tests:

Penetration at 77 F. scale converted):

Unworked 375. Worked 60 strokes. 368. ASTM Dropping Point. 378 F Copper Corrosion, 24 hours at 77 Neg. Shell Roll Penetration at 77 F.

scale converted):

1 hour 394. 24 hours 4.315 AAR Bleeding 'lest, Total Bleed, 17.3%

evaporation 4.3%. ASTM D 1743-601 Rust Test. Pass. Additive solubility Excellent.

Example 9 The grease of Example was formulated using 1.0 percent by weight of the reaction product of Example 3 as the rust inhibitor. The results are tabulated in Table V.

Examples l4 The grease of Example 5 was formulated with 1.0, 1.25, 1.50, 1.75 and 2.0 percent by weight of the reaction product of Example 1. The results of tests made on these batches are tabulated in Table V.

Examples -18 A calcium base grease was made by adding 731 grams of tallow and 244 grams of tallow fatty acids to a grease kettle and heating to 160 F. while stirring, after which 327 grams of base oil was added and thoroughly mixed. A slurry of 138 grams of lime and 338 grams of water was then added and mixed for about 10 minutes at 160 F. The temperature was then raised to 230-240 F. to complete the saponification of the fats and to dehydrate the soap-oil mixture. The kettle was cooled and base oil slowly added to a total of 2267 grams. 84 grams of set water then was added to the kettle while stirring to form a heavy grease to which about 3000 grams of base oil were added. The formulation is shown in Table VI. 0.0, 0.75, 1.0, 1.5, 2.0 (acid grease) and 2.0 percent by weight of the reaction product of Example 1 was formulated in the grease. The results of tests made on the grease are shown in Table V.

Examples 19-20 The calcium grease of Example 15 was formulated with 0.75, 1.0, 1.5, and 2.0 percent by weight of the reaction product of caprylic acid and an imidazoline represented by the structure:

( z)nNH:

where R is heptadecenyl and n is an integer from 1 to 4. The results of tests conducted on the grease are shown in Table V.

8 Examples 21-23 A barium grease having the following composition:

was made by adding 500 grams of hydrogenated castor oil to a grease kettle, and heating to melt the fats, after which 500 grains of mineral oil were added and the mixture heated to 170-1 F. with the kettle paddles turning. 273.4 grams of barium hydroxide and 350 grams of water were then added. Heating was continued with paddles turning to saponify the fats. The temperature was held below 200 F. preferably about 190 F. for five hours and then increased to approximately 290 F. for an additional five hours to dehydrate the soap oil mixture.

Mineral oil was then added slowly to a total of 2162.6 grams while turning paddles and 13.60 grams ortholeum 300 added and mixed thoroughly. The grease was cooled to BO- F. and then drawn from the kettle. The

formulation was as follows:

Formulation: Grams Hydrogenated castor oil 500 Starting oil Western solvent treated-Vis The grease was compounded with 0.0, 0.75, 1.00, 1.50, and 2.00 percent of the reaction product of Example 1. The results of tests made on this grease are shown in Table V.

Example 24 The lithium grease of Example 5 was formulated with 1,2-dia1kyl imidazoline in amounts up to 2.5 percent. At less than 2.5 percent the grease did not pass the rust test. At 2.5 percent the grease passed the rust test but had very poor water tolerance.

The above results demonstrate the effectiveness of grease compositions of the present invention to resist corrosion while, at the same time, preserving the water tolerance and any physical properties of the grease. It was found that the imidazoline was unsatisfactory as a grease rust inhibitor, but that the imidazoline salts of certain fatty acids impart excellent rust inhibiting properties to greases. The data show that the inclusion of at least about 0.75 percent by weight of the rust inhibitor is required with the optimum range being 0.75 percent to 2.0 percent.

Example 25 The imidazoline salt formed in Example 3 was refluxed in xylene at 280 F. for approximately 2 hours to drive off the equivalent of 1 mole of water per mole of the salt to form an imidazoline amide. The xylene was then distilled from the amide.

Example 26 The grease of Example 5 was formulated using 1.0 percent by weight of the imidazoline amide of Example 25 as the rust inhibitor. The results are tabulated in Table V and show that this grease failed the rust test.

Example 27 The imidazoline salt formed in Example 1 was amidified by heating to a temperature above 275 F. to drive otf approximately 1 mole of water per mole of salt.

9, Example 28- The grease of Example 5 was formulated using 0.88

expulsion of water, whereinsaid imidazoline is selected from the group consisting- A r N--CH3 N--GH5 N-CH1 percent of the imidazo hne amide produced in Example R it R C I H H H II l 27 as the rust inhibitor. The results of tests run on this 5 2 2 and C 3(0 2 grease are listed in Table V and show that this grease I N failed the 111st test. 1 CHQ J R1 TABLE V Water Absorption Percent Per- Unworked ASTM. (Grease Worker) Water Absorptiou Test Test. Shell Roller Ex. Add, Wt. cent Pen. at (D1743-60T) 4 Hour Remarks No. Percent Alk. 77 F. Rust Test r 1 i Percent Pen. at Percent Pen. at Percent; Pen. at

Water 77 F. Water 77 1}. Water 77 F.

9 1.0 .Pass Additivc solubility,

. v I excellent; 10 1.0 ..do Do. 11 1.25 360 .do 50 475 I 100 500+ 100-- I 415 This greeserejects part of g 100% H O in Shell Roller Absorption Test. Simulates action of grease in a. bearing. 12 1.50 359 .do 50 495 100 600+ l00 l 421 Thls'grease rejects a trace of free water in Shell Roller absorption test. Simulates action in a bearing. 13-..... l. 75 357 ...do 50 500+ 100 500+ 100- 1 430 This grease rejects a trace of free water in Shell Roller: absorption test. simulates action oi grease in a bearing. 14 2.00 360 do 86 9 418 14% water rejected. 15 None 0. 153 2 201 Fail 2 10 l 305 Consistency of grease ei'ter water absorption test,

' good. 16 0. 75 .076 304 Pass 2 100 316 Do. 17 2. 00 B 095 2 362 Fall 2 100 2 350 Acid grease-consistency after water absorption I test, good. 18 2. 00 0.114 2 832 Pass 2 100 2 368 Alkaline grease. Approx.

5 j 28% water separated on standing over weekend. Consistency after water r test, fair. 19 1. 50 0. 119 2 331 do 2 100 5 347 Consistency-good after Water abs. test. 20 2.00 0.119 2 389 do 1 100 l 359 Free oil separating from water-grease mixture over weekend. Consistency after Water test, good. 21 None 0. 071 2 251 274 22 1. 0.07 2 263 310 Grease structure after water abs. test-good, tacky and fibrous. 23 2.00 0. 14 2 265 344 Grease structure after water abs. test-dair still tacky and fibrous, considerably softer than Example 22. 26 1. 00 2 291 Fail 2 30 2 294 28 0.88 278 .....do 34 270 1 Consistency good. 4 26% H2O absorbed. 2 }6 Scale Conversion. 6 32% B20 absorbed. 3 Oleic. 56% E20 absorbed.

F 1 TABLE VI where n 1s an integer of from 1 to 4, and R and R are ormu iiltlfln. 731 5r selected from the group consisting of hydrogen and an f 244 0 aliphatic hydrocarbon having from about 5 to 17 carbon E? Ow attyHacl s 138 atoms, said grease having an excess alkalinity.

Cam )2 338 2. The grease composition of claim 1 consisting essenwater hall of the followln corn os1t1on:

y g P Base O1I--Naphthen1c Type Pfircent by Weight O 300*320 SUS at 100 ";"S;" 60 Lithium 12-hydroxystea'r1c acid soap 7 ap c n Lithium sea of a eutectic mixture containin 68% Penetration at 77 F. 291 p g Although my present invention has been described with a certain degree of particularity, it is to be understood that our invention is not to be limited to the details set forth but should be given the full scope of the appended claims.

I claim:

1. A grease composition comprising a mineral oil of lubricating viscosity, a soap-thickening agent in an amount sufficient to gel said lubricating oil to grease consistency, and a rust inhibiting amount of an imidazoline salt of a fatty acid having from 6 to 18 carbon atoms formed at a reaction temperature of less than 275 F. without the pal-mitic acid, 30% stearic acid, and 2% oleic acid .4 Base oil viscosity 50-100 SUS at 210 F. 91 Imidazoline salt .75 Diphenyl amine oxidation inhibitor .5

and wherein said finished grease has an excess alkalinity of about 0.038% by weight lithium hydroxide.

3. The grease composition of claim 1 wherein said imidazoline salt is present in an amount of at least 0.75 percent by weight and said grease has an excess alkalinity as metal hydroxide of about 0.02 to 0.14% by weight.

4. The grease composition of claim 1 wherein the fatty acid is caprylic acid.

5. The grease composition of claim 1 wherein the imidazoline is 1-(2-amino ethyl)-2-n-heptadecenyl-2-imidazoline.

6. The grease composition of claim 1 wherein the imidazoline is represented by the formula:

l] II--([]Hz R-C CH2 i Qn z where R is selected from the group consisting of hydrogen and an aliphatic hydrocarbon having from about 5 to 17 carbon atoms, and n is an integer of at least 1.

7. The grease composition of claim 1 wherein said reaction product is present in an amount ranging from about .75 to 2 percent by weight.

8. A grease 'composition comprising a mineral oil of lubricating viscosity, a soap-thickening agent in an amount sufiicient to gel said lubricating oil to grease consistency, and a rust inhibiting amount of an imidazoline salt selected from the group-consisting of:

and mixtures thereof wherein n is an integer of from 1 to 4 and R, R and R are selected from the group consisting of aliphatic hydrocarbons having 5 to 17 carbon atoms, said imidazoline salt being formed at a reaction temperature of less than 275 F; and without the expulsion of water and said grease having an excess alkalinity as a metal hydroxide of about 0.02 to 0.14% by weight. 9. The grease composition of claim 8 wherein the imidazoline salt is represented by the formula:

where R is heptadecenyl and R is heptyl.

10. The grease composition of claim 8 wherein the imidazoline salt is present in an amount of at least 1 percent by weight.

IL The grease composition of claim 1 wherein said fatty acid material is caproic acid.

12. The grease composition of claim 1 wherein said fatty acid is capric acid.

13. The grease composition of claim 1 wherein said imidazoline salt is a mixture of the imidazoline salts defined therein.

References Cited UNITED STATES PATENTS 2,466,517 4/1949 Blair et al. 252-392 2,490,744. 12/1949 Trigg et al. 25251.5 2,991,249 7/1961 Andress et a1. 25242.1

DANIEL E. WYMAN, Primary Examiner.

IRVING VAUGHN, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION June 25, 1968 Patent No. 3,390,085

Peter E. Floeck It is certified that error appears in the above identified .patent and that said Letter Patent are hereby corrected as' shown below: l Column- 2 line 54, "hydration" should read --;{dehydration Column 3, line 56, after "specified", second occurrence, insert the reactants Column 6, TABLE II, third column, line 4 thereof, "3.971" should read 3.975 TABLE III, approximately line 55, under "Inspection Tests:".and opposite "Penetration change 100,000 strokes", "6" should read -6 same table, approximately lines 71 and 72, "(is scale converted)" should read,- (1/2 scale converted) Column 7,, TABLE IV,

approximately line 28, opposite the item "24 hours", "4.315

should read 15 Signed and sealed this 16th day of December 1969.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Commissioner of Patents Edward M. Fletcher, Jr. Attesting Officer