US3920571A

US3920571A - Grease composition and method of preparing the same

Info

Publication number: US3920571A
Application number: US506062A
Authority: US
Inventors: Richard E Crocker
Original assignee: Chevron Research and Technology Co
Current assignee: Chevron USA Inc
Priority date: 1974-09-16
Filing date: 1974-09-16
Publication date: 1975-11-18
Anticipated expiration: 1992-11-18
Also published as: FR2304662A1; FR2284669B1; FR2304662B1; GB1519616A; NL170752C; FR2284669A1; US3983041A; DE2540470A1; NL170752B; NL7602931A; DE2610879C2; NL7510889A; AU1221076A; BE839738A; DE2610879A1

Abstract

A novel grease composition is prepared by admixing a lubricating oil with 0.5 to 10 weight percent of a mono- or polyurea compound or mixture of mono- and/or polyurea compounds having from 1 to 8 ureido groups and having a molecular weight between about 375 to 2,500 and from 3 to 30 weight percent of an alkaline earth metal carbonate.

Description

United States Patent [191 Crocker [4 1 Nov. 18, 1975 1 GREASE COMPOSITION AND METHOD OF PREPARING THE SAME [7 5] lnventor: Richard E. Crocker, Novato, Calif.

[73] Assignee: Chevron Research Company, San

Francisco, Calif.

[22] Filed: Sept. 16, 1974 [21] Appl. No.: 506,062

[52] US. Cl. 252/25; 252/51.5 A [51] Int. C13. CIOM l/l0; ClOM 3/02; ClOM 5/02;

C10M 7/02 [58] Field of Search 252/25, 51.5 A

[56] References Cited UNITED STATES PATENTS 3,007,866 11/1961 Chamberlin ..252/40.7

3,843,528 10/1974 Bailey et al. 252/25 11/1974 Dreher et a1 252/25 Primary ExaminerDelbert E. Gantz Assistant Examiner-I. Vaughn Attorney, Agent, or Firm-G. F. Magdeburger; C. J. Tonkin [57] ABSTRACT 17 Claims, No Drawings GREASE COMPOSITION AND METHOD OF PREPARING THE SAME BACKGROUND OF THE INVENTION Modern technology is currently supplying the general public and the process industries with machinery which is designed to operate under a wider range of temperatures and under greater loads than previously available. In addition, many of the newer machines are designed to operate at extremely high speeds. Many of these machines require certain specific lubricating properties which are not available in the conventional lubricants. Thus, modernization of high-speed and high-temperature equipment has strained the petroleum industry for the development of a second generation of lubricants capable of satisfying the requirements of the new machines. Recently, for example, there has been an increased demand for lubricants capable of performing well at temperatures above 300F. in high-speed bearings and gears for periods in excess of 500 hours. In addition, with the further development of the high-speed sealed bearings, the lubricant must be able to endure for the life of the bearing.

There have been numerous grease compositions developed which satisfy most of the new, more stringent requirements. Many of these compositiions, however, are entirely too expensive for commercialization or only meet some of the lubricating requirements and fail in others. One type of lubricant currently available is the ubiquitous lithium greases. These greases are simply a mixxture of a hydrocarbon base oil and lithium hydroxy stearate with minor amounts of other additives. Although these greases exhibit good-lubricating properties and perform well at moderate temperatures, their application in high-temperature and high-speed machinery has not been entirely successful. The lithium greases tend to deteriorate in these machines at-high.

temperatures, particularly at temperatures above 300F. The deterioration leads to a rapid loss of lubrication and ultimately failure of the equipment.

Another type of grease composition which has excellent lubricating properties at the higher temperatures is comprised of a lubricating oil (natural or synthetic) containing a polyurea additive. This type of lubricant is disclosed in US. Pat. Nos. 3,242,210, 3,243,372, 3,346,497, and 3,401,027, all assigned to Chevron Research Company. The polyurea component imparts a significant high-temperature stability to the grease. While this grease has solved most of the problems associated with the older lubricants, it is handicapped by the requirement of relatively large amounts of polyurea (between 8 and weight percent) and its relatively high costs. In addition, the polyurea component does not impart extreme-pressure properties to the lubricant and, accordingly, EP additives must be added in applications involving high contact pressures. A need therefore exists for a grease composition which can be used in high-temperature and high-speed applications, that exhibits good stability over prolonged periods, that exhibits both extreme-pressure and antiwear properties, and that is relatively inexpensive to produce.

It is, therefore, an object of this invention to provide a new, improved grease composition.

It is another object of this invention to provide an improved grease composition capable of performing well at high temperatures for prolonged periods.

2 It is another object of this invention to provide a relatively inexpensive grease composition capable of performing well at high temperatures in high-speed application and which exhibits good EP properties.

It is another object of this invention to provide a method for making an improved grease composition.

SUMMARY OF THE INVENTION The aforegoing objects and their attendant advantages can be realized by a composition comprising a major part of a lubricating oil containing: (1 from 0.5

to 10 weight percent of a monoor polyurea compound.

in mixture of monoand/or polyurea compounds having an average of 1 to 8 ureido groups and having a number average molecular weight between about 375 and 2,500; and (2) from 3 to weight percent of an alkaline earth metal carbonate.

By incorporating an alkaline earth metal carbonate within the grease composition, I have found that the monoor polyurea content may be reduced by as much as 50% of that required in the prior monoor polyurea lubricants for the same dropping point and other physical properties. Moreover, the' presence of the metal carbonate imparts excellent extremepressure properties to the lubricant, and thus the addition of'other EP additives is not necessary in many applications.

The exact mechanism of the monoor polyurea compounds and the metal carbonate in effecting the improved lubricating properties is unknown. However, without being bound by the theory, it is believed that the alkaline earth metal carbonate complexes in'some manner with the monoor'polyurea compounds to effect a combined thickeningaction. Although the exact mechanism is unknown, 1 have found that a synergism exists between the two components suchthat the lubricating properties of the grease are substantially improved over either the monoor polyurea thickener or metal carbonate employed alone. For example, the

40 combination effects a remarkable increase in the extreme-pressure properties of the grease.

Monoor Polyurea Component The monoor polyurea component of this invention is a waterand oil-soluble organic compound or mixture of compounds having a number average molecular weight between about 350 and 2,500 and having an average of at least 1 ureido group and preferably having an average between about 2 and 6 ureido groups. A

particularly preferred polyurea thickener has an averprepared by reacting the following components:

I. A diisocyanate or mixture of diisocyanates having the formula OCNR-NCO, wherein R is a hydrocarbylene having from 2 to 30 carbons, preferably from 6 to 15 carbons, and more preferably 7 carbons;

II. A polyamine or mixture of polyamines having a total of 2 to 40 carbons and having the formula:

LII

wherein R and R are the same or different type of hydrocarbylenes having from 1 to 30 carbons, and preferably from 2 to 10 carbons, and more preferably from 2 to 4 carbons; R is selected from hydrogenor a C1-C4 alkyl, and preferably hydrogen; x is an integer from O to 4; y is 0 or 1; and z is an integer equal to 0 when y is 1 and equal to 1 when y is O.

111. A monofunctional component selected from the group consisting of monoisocyanate or mixture of monoisocyanates having 1 to 30 carbons, preferably from to 24 carbons, a monoamine or mixture of monoamines having from 1 to 30 carbons, preferably from 10 to 24 carbons, and mixtures thereof.

The reaction can be conducted by contacting the three reactants in a suitable reaction vessel at a temperature between about 60 to 320F., preferably from 100 to 300F., for a period from 0.5 to 5 hours and preferably from 1 to 3 hours. The molar ratio of the reactants present usually varies from 0.1-2 molar parts of monoamine or monoisocyanate and O-2 molar parts of polyamine for each molar part of diisocyanate. When the monoamine is employed, the molar quantities are preferably (m+l) molar parts of diisocyanate, (m) molar parts of polyamine and 2 molar parts of monoamine. When the monoisocyanate is employed, the molar quantities are preferably (m) molar parts of diisocya- The monoor polyureas having the structure presented in Formula 1 above are prepared by reacting (n+1 molar parts of diisocyanate with 2 molar parts of a monoamine and (n) molar parts of a diamine. (When n equals zero in the above Formula 1, the diamine is deleted). Monoe or polyureas having the structure presented in Formula 2 above are prepared by reacting (n) molar parts of a diisocyanate with (n+1 molar parts of a diamine and 2 molar parts of a monoisocyanate.

(When n equals zero in the above Formula 2, the diisocyanate is deleted). Monoor polyureas having the structure presented in Formula 3 above are prepared by reacting (n) molar parts of a diisocyanate with (n) molar parts of a diamine and 1 molar part ofa monoisocyanate and 1 molar part of a monoamine. (When n equals zero in Formula 3, boththe diisocyanate and diamine are deleted).

in preparing the preferred above monoor polyureas, the desired reactants (diisocyanate, monoisocyanate, diamine and monoamine) are admixed within a suitable reaction vessel in the proper proportions. The reaction may proceed without the presence of a catalyst and is initiated by merely contacting the component reactants under conditions conducive for the reaction. Typical reaction temperatures range from 20C. to 100C. under atmospheric pressure. The reaction itself is exothermic and, accordingly, by initiating the reaction at room temperature elevated temperatures are obtained. However, external heating or cooling may be desirable.

Reactants The monoamine or monoisocyanate used in the formulation of the monoor polyurea will form the termiwherein n is an integer from 0 to 3; R is the same or different hydrocarbyl having from 1 to 30 carbon atoms, preferably from 10 to 24 carbons; R is the same or different hydrocarbylene having from 2 to 30 carbon I atoms, preferably from 6- to 15 carbons; and R is the same or different hydrocarbylene having from 1 to 30 carbon atoms, preferably from 2 to 10 carbons.

As referred to herein, hydrocarbyl is a monovalent organic radical composed essentially of hydrogen and carbon and may be aliphatic, aromatic or alicyclic or combinations thereof, e.g., aralkyl, alkyl, aryl, cycloalkyl, alkylcycloalkyl, etc., and may be saturated or olefinically unsaturated (one or more double-bonded carbons, conjugated or nonconjugated). The hydrocarbylene, as defined in R and R above, is a divalent hydrocarbon radical which rnay be aliphatic, alicyclic, aromatic or combinations thereof, e.g., alkylaryl, aralkyl, alkylcycloalkyl, cycloalkylaryl, etc., having its two free valences on different carbon atoms.

nal end groups. These terminal end groups will have from 1 to 30 carbon atoms, but are preferably from 5 to 28 carbon atoms, and more desirably from 10 to 24 carbon atoms.

Illustrative of various monoamines are pentylamine,

hexylamine, heptylamine, octylamine, decylamine, dodecylamine, tetradecylamine, hexadecylamine, octadecylamine, eicosylamine, dodecenylamine, hexeleostearlyamine, etc. The unsaturated amines are particularly preferred.

Illustrative of monoisocyanates are hexylisocyanate, decylisocyanate, dodecylisocyanate, tetradecylisocyanate, hexadccylisocyanate, phenylisocyanate, cyclohexylisocyanate, xyleneisocyanate, cumeneisocyanate, abietylisocyanate, cyclooctylisocyanate, etc.

The polyamines which form the internal hydrocarbon bridges between the ureido groups usually contain from 2 to 40 carbons and preferably from 2 to 30 carbon atoms, more preferably from 2 to 20 carbon atoms. The polyamine preferably has from 2 to 6 amine nitrogens, preferably 2 to 4 amine nitrogens and more preferably 2 amine nitrogens. Exemplary polyamines include diamines such as ethylenediamine, propanediamine, butanediamine, hexanediamine, dodecanediamine, octanediamine, hexadecanediamine, cyclohexanediamine, cyclooctanediamine, phenylenediamine, tolylenediamine, xylylenediamine, dianiline methane, ditoluidinemethane, bis(aniline), bis(toluid ine), piperazine, etc.; triamines, such as aminoethyl piperazine, diethylene triamine, dipropylene triamine, N-methyldiethylene triamine, etc., and higher polyamines such as triethylene tetraamine, tetraethylene pentaamine, pentaethylene hexamine, etc.

Representative examples of diisocyanates include hexane diisocyanate, decanediisocyanate, octadecanediisocyanate, phenylenediisocyanate, tolylenediisocyanate, bis(diphenylisocyanate), methylene bis(phenylisocyanate), etc.

Another preferred class of monoor polyurea compounds which may be successfully employed in the practice of this invention include the following:

wherein n is an integer of l to 3, R is defined supra; X and Y are monovalent radicals selected from Table I .below:

TABLE I In Table I, R is defined supra, R" is the same as R and defined supra, R is selected from the group consisting of arylene radicals of 6 to 16 carbon atoms and alkylene groups of 2 to 30 carbon atoms, and R is selected from the group consisting of alkyl radicals having from 10 to 30'carbon atoms and aryl radicals having from 6 to 16 carbon atoms.

Monoor polyurea compounds described by the above Formula 4 can be described as amides and imides of mono-, di and triureas. These materials are formed by reacting in the selected proportions suitable carboxylic acids or internal carboxylic anhydrides with a diisocyanate and a polyamine with or without a monoamine or monoisocyanate. The monoor polyurea compounds are prepared by blending the several reactants together in a suitable reaction vessel and heating them to a temperature ranging from 70F. to 400F. for a period sufficient to cause formation of the compound, generally from 5 minutes to 1 hour. The reactants can be added all at once or sequentially.

Suitable carboxylic acids include aliphatic carboxylic acids of about 1 l to 31 carbon atoms and aromatic carboxylic acid of 7 to 17 carbon atoms. Examples of suitable acids include aliphatic acids such as lauric, myristic, palmitic, margaric, stearic, arachidic, behenic acid, etc.; and aromatic acids such as benzoic acid, l-naphthoic acid, 2-naphthoic acid, phenylacetic acid, hydrocinnamic acid, cinnamic acid, mandelic acid, etc. Suitable anhydrides which may be employed are those derived from dibasic acids which form a cyclic anhydride structure, for example succinic anhydride, maleic anhydride, phthalic anhydride, etc.- Substituted anhydrides, such as alkenyl succinic anhydride of up to 30 carbon atoms, are further examples of suitable materials.

Examples of suitable diisocyanates, monoisocyanates, monoamines and polyamines are described supra.

All of the above-described monoor polyureas when prepared by the method of this invention are generally mixtures of compounds having structures wherein n or n varies from 0 to 8, or n or n varies from I to 8, existent within the grease composition at the same time. For example, when a monoamine, a diisocyanate and a diamine are concurrently present within the reaction zone, as in the preparation of ureas having the structure shown in Formula 2, some of the monoamine may react with both sides of the diisocyanate to form a diurea. In addition to the formulation of diurea, simultaneous reactions can be occuring to form the tri-, tetra-, penta-, hexa-, octa-, and higher polyureas. Particularly good results have been realized when the polyurea compound has an average of 4 ureido groups.

The amount of monoor polyurea thickener in the final grease composition will be sufficient to thicken the base oil to the consistency of grease when combined with the alkaline earth metal carbonate. Generally the amount of 'monoand polyurea thickener will range from I to 15 weight percent and preferably from 2 to 10 weight percent, and more preferably from 3 to 7 weight percent of the final grease composition.

In instances where an oil concentrate is desired, the concentration of the monoand polyurea thickener in the base oil or an oleaginous organic liquid can vary between about l0 and 30 weight percent of the final concentrate. The employment of concentrates provides a convenient method of handling and transporting the monoor polyurea thickener for subsequent dilution and use.

Alkaline Earth Metal Carbonate The second component of the grease composition is an alkaline earth metal carbonate. Any of the alkaline 7 bonate, barium carbonate and magnesium carbonate.

The amount of alkaline earth metal carbonate present within the grease composition may vary depending upon the lubricating property desired, the particular monoor polyurea constituent selected, the type of alkaline earth metal carbonate selected, etc. However, generally the metal carbonate will range from 3 to 30 weight percent of the final grease composition and preferably between about 4 and weight percent. The ratio of alkaline earth metal carbonate to the monoor polyurea constituent will also vary depending upon the aforementioned conditions, but will generally range on a weight basis from 0.l to parts of metal carbonate per part of monoand polyurea, preferably from 1 to 10 parts per part of monoand polyurea and more preferably from 3 to 7 parts per part of monoand polyurea. (If there is no monourea present, then only the polyurea is used in calculating the ratios).

A concentrate of the monoor polyurea thickener and metal carbonate may also be formulated. The concentration of the metal carbonate can vary from 20 to 50 weight percent and preferably from to 40 weight percent of the concentrate. The base oil is the preferred liquid medium of the concentrate, since it can be readily diluted to form the desired grease composition.

Base Oil The third component which must necessarily be present in the composition of this invention is a liquid base oil. The base oils which may be employed herein include a wide variety of lubricating oils such as naphthenic-base, paraffin-base, and mixed-base lubricating oils. Other hydrocarbon oils include lubricating oils derived from coal products and synthetic oils, e.g., alkylene polymers (such as polymers of propylene, butylene, etc., and mixtures thereof), alkylene oxide-type polymers (e.g., alkylene oxide polymers prepared by polymerizing alkylene oxide, e.g., propylene oxide polymers, etc., in the presence of water or alcohols, e.g., ethyl alcohol), carboxylic acid esters (e.g., those which were prepared by esterifying such carboxylic acids as adipic acid, azelaic acid, suberic acid, sebacic acid, alkenyl succinic acid, fumaric acid, maleic acid, etc., with the alcohols such as butyl alcohol, hexyl alcohol, 2-ethylhexyl alcohol, etc.), liquid estersof acids of phosphorus, alkylbenzenes, polyphenols (e.g., biphenols and terphenols), alkyl biphenol ethers. polymers of silicon, e.g., tetraethyl silicate, tetraisopropyl silicate, tetra(4-methyl-2-tetraethyl) silicate, hexyl(4- methyl-2-pentoxy)disilicone, poly(methyl)siloxane, and poly(methylphenyl)siloxane, etc. The base oils may be used individually or in combinations, whenever miscible or whenever made so by use of mutual solvents. The viscosity of the base oil may vary from 50 to 10,000 SUS at 100F. and preferably from 100 to 2,000 SUS.

Preparation of Grease Composition The greases exhibiting superior properties of the invention can be, and are preferably, prepared by the insitu production of the monoor polyurea thickener followed by the in-situ production of the alkaline earth metal carbonate within the base oil. In this embodiment, the base oil is charged to the grease kettle along with the monoor polyurea precursors and thereinafter the metal carbonate precursors, i.e., the reactants which combine to form the monoor polyurea thickener and metal carbonate. In instances where the pre- 8 ferred monoor polyurea compounds are of the type defined by Formula I, the base oil is charged with the desired proportion of diisocyanate, diamine and monoamine. In the preparation of monoor polyurea defined by Formula 2, the base oil is admixed with the desired proportion of diisocyanate, diamine and monoisocyanate. If the monoor polyurea is of the type defined by Formula 3, then the desired proportion of diisocyanate, diamine, monoisocyanate and monoamine are admixed with the base oil. In instances where the monoor polyurea compound is of the type defined in Formula 4, the base oil is charged with the desired proportion of carboxylic acid or anhydride, diisocyanate, diamine, and monoamine or monoisocyanate. The kettle contents are agitated and'the temperature is raised to 20 to 160C. and maintained at that temperature for a period sufficient to cause formation of the mono or polyurea compound, generally between about 0.5 i and 5 hours.

After the formation of the monoor polyurea thickener, the grease kettle is charged with an alkaline earth metal base such as the hydroxide or oxide. Carbon dioxide is then introduced into the solution and in contact with the alkaline earth metal base. The carbon dioxide may be bubbled into the solution or generated in situ by the decomposition of urea CO(NI-I or the like. The amount of carbon dioxide introduced into the solution may vary from 0.1 to 10 molar parts per molar part of alkaline earth metal base and preferably from 0.5 to 0.9 molar part per molar part of alkaline earth metal base. The kettle is preferably maintained at a temperature between and 160C. during the process to effect the reaction of the alkaline earth metal hydroxide or oxide and the carbon dioxide. During the reaction water may be released and is preferably removed from the system by applying a vacuum on the kettle of 20-29 inches (50.8 73.6 cm) Hg and heating to about C. and higher.'

The grease composition can be further processed by subjecting it to shear hardening. Shear hardening is performed by milling the grease in an extrusion-type mill under elevated pressures. This milling improves the dispersion of the monoor polyurea and metal carbonate throughout the base oil, resulting in a grease of greatly improved consistency. US. Pat. Ser. No. 111.517, filed Feb. I, 1971, now abandoned, discloses a preferred method of shear hardening a grease which can be successfully employed for the compositions of this invention.

In addition to the monoand polyurea thickener and alkaline earth metal carbonate, other additives may be successfully employed within the grease composition of this invention without affecting its high stability and performance over a wide temperature scale. One type of additive is an antioxidant or oxidation inhibitor. This type of additive is employed to prevent varnish and sludge formation on metal parts and to inhibit corrosion of alloyed bearings. Typical antioxidants are organic compounds containing sulfur, phosphorus or nitrogen, such as organic amines, sulfides, hydroxy sulfides, phenols, etc., alone or in combination with metals like zinc, tin or barium. Particularly useful grease antioxidants include phenyl-alpha-naphthyl amine, bis- (alkylphenyl)amine, N,N-diphenyl-p-phe-nylenediamine, 2,2,4-trimethyldihydroquinoline oligomer, bis(4- isopropylaminophenyl)ether, N-acyl-p-amino-phenol, N-acylphenothiazines, N-hydrocarbylamides of ethylenediamine tetraacetic' acid, alkylphenol-forrnalde- 9 hyde-amine poly condensates, etc.

Another additive which may be incorporated into the grease composition of this invention is an anticorrodam. The anticorrodant is employed to suppress attack by acidic bodies and to form protective films over the metal surfaces which decrease the effect of corrosive materials on exposed metallic parts. A particularly effective corrosion inhibitor is an alkali metal nitrite, and preferably sodium nitrite. The combination of the monoor polyurea thickener and alkaline earth metal carbonate has been found to work exceedingly well with the alkali metal nitrite. When this corrosion inhibitor is employed it is usually used at a concentration of 0.1 to weight percent and preferably from 0.2 to 2 weight percent, based on the weight of the final grease composition.

Another type of additive which may be employed herein is a metal deactivator. This type of additive is employed to prevent or counteract catalytic effects of metal on oxidation generally by forming catalytically inactive complexes with soluble or insoluble metal ions.

Typical metal deactivators include complex organic nitrogen and sulfur-containing compounds such as certain complex amines and sulfides. An exemplary metal deactivator is mercaptobenzothiazole.

A particularly preferred additive is an alkaline earth metal carboxylate having from 1 to 3 carbons. This additive may be present in an amount from 1 to weight percent, preferably from 1 to 8 weight percent. The presence of the alkaline earth metal carboxylate allows the formulation of the polyurea grease with less alkaline earth metal carbonate. The preferred weight ratio of alkaline earth metal carboxylate to alkaline earth metal carbonate is 0.1 to 10 and preferably 0.5 to 5. The preferred alkaline earth metal carboxylate is calcium acetate.

In addition to the above, several other grease additives may be employed in the practice of this invention and include stabilizers, tackiness agents, dropping point improvers, lubricating agents, color correctors, odor control agents, etc. V

The following examples are presented to illustrate the practice of specific embodiments of this invention and should not be interpreted as limitations upon the scope of the invention.

EXAMPLES Example 1 This example is presented to demonstrate the improvement in a typical polyurea grease by the combination of a polyurea thickener with an alkaline earth metal carbonate. In this example, three grease samples are prepared and then tested for their properties. The grease samples are prepared as follows:

A grease kettle is charged with 8184 g of a blend of a paraffinic and naphthenic oil having a viscosity of 78 SUS at 210F., hereinafter referred to as base oil, 1 17 g of ethylene diamine and 1064 g of oleyl amine. Contents of the kettle are stirred for approximately 50 minutes and heated to 120F. Thereafter, 680 g of tolylene diisocyanate in 5494 g of base oil are charged to the kettle. The kettle is agitated and held at a temperature ranging between 140 and 150F. during the addition period.

The kettle contents are thereafter milled in an extrusion-type mill at 7,500 psi and then heated to 178F. for 45 minutes. A small sample of the grease is analyzed and trace amounts of diisocyanate are detected. An additional 20 g of ethylene diamine are charged to the kettle and mixed with the milled grease for a period of 20 minutes at a temperature of 178F. At the end of this period, the kettle is charged with an additional 17,508 g of the base oil. A 3,500-g portion of the grease contents in the kettle is removed and is referred to hereinafter as Sample A.

To the remainder of the grease composition within the kettle is added 3000 g of calcium hydroxide. The composition is milled for approximately 50 minutes and held at a temperature between 182 and 175F. At the end of this period, a conventional sodium nitrite rust inhibitor is added. A second 3,500-g sample is removed from the kettle and this sample is hereinafter referred to as Sample B."

Carbon dioxide is passed through the remainder of the kettle contents at a pressure of psi at a temperature of 174F. The temperature is increased to 300F. and held at that temperature and pressure for approximately 1 hour. After 750 g of carbon dioxide are absorbed into the kettles contents, the contents are cooled to 198F. Thereafter, 683 g of a Mannich base rust inhibitor are added. A 625-g sample is removed from the kettle and is hereinafter referred to as Sample C.

Samples A and B are then separately heated to 300F. and cooled. Samples A, B, and C are then put through a three-roll paint mill to shear the greases to a harder consistency. The roller settings on the mill are held constant.

Samples A, B and C are subjected to ASTM Work Penetration Test (ASTM-217), ASTM Timken Test (D-2509) and an ASTM Dropping Point Test (D- 2265). Results of these tests are illustrated in the following Table II. In addition, the composition (Sample D) prepared by the method of Example 2 in US. Pat. Ser. No. 363,210, filed May 23, 1973, now U.S. Pat. No. 3,846,314, is also presented in Table 11 for a direct comparison of the properties. Also the testing on a polyurea calcium acetate calcium carbonate grease (Sample E) is also shown in Table II. This grease is prepared by the method of Example 2.

This example is presented to demonstrate the preparation of a polyurea alkaline earth metal carbonate alkaline earth metal carboxylate grease composition of this invention. The polyurea thickener is prepared in the same manner shown in Example 1 except that the following amounts are used.

Component Weight (grams) Oleyl monoamine 1816 -continued Component Weight (grams) Tolylene diisocyanate l 160 Ethylene diamine 200 To the polyurea containing solution, the kettle is. charged with 5,120 grams of calcium hydroxide and the contents heated to 190F. and milled for 15 minutes. Thereafter 1,536 grams of acetic acid are added. .800 grams of sodium nitrite in 2000 grams of water are then added and the mixture milled for 30 minutes. One-half of the mixture is removed and 1260 grams of urea in 1,500 grams of water are added to the remaining onehalf in the kettle. The contents are heated to 320F. over a 3% hour period. The contents are cooled and 1,600 grams of a Mannich base rust inhibitor are added along with 160 grams of a commerical anti-oxidant. The product is then milled for minutes. The grease sample had an ASTM Work Penetration of 272.

What is claimed is:

1. A grease composition comprising a major part of a lubricating oil containing: (1) from 0.5 to 10 weight percent of a thickener selected from monoor polyurea compounds or a mixture of monoor polyurea compounds having an average from 1 to 8 ureido groups and having a number average molecular weight between about 375 and 2,500; and (2) from 3 to 30 weight percent of an alkaline earth metal carbonate.

2. The composition defined in claim 1, wherein said alkaline earth metal carbonate is calcium carbonate.

3. The composition defined in claim 2, wherein said monoor polyurea compound or mixture of monoand/or polyurea compounds has an average of 3 to 4 ureido groups and has a number average molecular weight between about 600 and 1,200, and wherein said lubricating oil is a hydrocarbon oil.

4. A grease composition comprising a major portion of an oil of lubricating viscosity, from 3 to 30 weight percent of an alkaline earth metal carbonate and a monoor polyurea compound or mixture of monoand/or polyurea compounds prepared by reacting the following components:

1. a diisocyanate having the formula OCN-R-NCO, wherein R is a hydrocarbylene having from 2 to 30 carbons; 7

11. a polyamine having a total of 2 to 40 carbons and having the formula:

wherein R and R are the same or different type of hydrocarbylene having from 1 to 30 carbons; R is hydro- 12 gen or a C1-C4 alkyl; x is an integer from 0 to 4; y is O or 1; and z is an integer equal to 0 when y is l and equal to 1 when y is 0; and

III. a monofunctional compound having from 1 to 30 carbons and selected from the group consisting of monoisocyanate, monoamine and mixtures thereof. wherein the reaction temperature is from about 60 to 320F., the reaction time is about 0.5 to 10 hours and the component molar ratios ofl to 11 to III are 1:02:O.l2.

5. The composition defined in claim 4 wherein said diisocyanate is tolylene diisocyanate, said polyamine is ethylene diamine and said monofunctional compound is a C12-C24 monoamine.

6. The composition defined in claim 5 wherein the molar ratio of diisocyanate to diamine to monoamine is 2:112.

7. The composition defined in claim 6 wherein said monoamine is tall oil fatty amine.

8. The composition defined in claim 4 wherein said polyamine is a triamine.

9. The composition defined in claim 8 wherein said triamine is tert-N-methyl diethylenetriamine.

10. The composition defined in claim 4 wherein said polyamine is piperazine.

11. The composition defined in claim 4 wherein said alkaline earth metal carbonate is calcium carbonaate.

12. The composition defined in claim 11 wherein said oil of lubricating viscosity is a naphthenic or paraffinic hydrocarbon lubricating oil or mixture thereof.

13. The composition defined in claim 12 wherein an alkali metal nitrite is also present.

14. The composition defined in claim 13 wherein said alkali metal nitrite is sodium nitrite.

15. The composition defined in claim 14, wherein said alkaline earth metal carbonate is calcium carbonate.

16. The composition defined in claim 15 wherein said monoamine is oleyl amine.

17. A method for preparing a grease composition which comprises:

1. admixing a C4 to C32 diisocyanate. a C2 to C40 polyamine and a C1 to C30 monoamine within a major portion ofa lubricating oil, the molar ratio of diisocyanate to polyamine to monoamine being l:O2:0.l-2;

ll. maintaining said admixture at a temperature of 60 to 320F. for a period of 0.5 to 10 hours;

111. thereafter adding an alkaline earth metal hydroxide or oxide to said admixture;

1V. contacting said admixture with 0.1 to 10 molar parts of carbon dioxide per molar part of alkaline earth metal base; and

(V) thereafter milling said admixture to the consis- UNITED STATES PATENT AND'TRADE-MARK OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,920,571 DATED November 18 1975 lNVENTO I Richard E. Crocker It is certified that error appears-in the above-identified patent and that said Letters Patent are hereby corrected as shown-below:

On the Preamble page, the following sentences should be added to the Abstract of the Disclosure --This invention relates to a new grease composition. More particularly, this invention relates to an improved grease lubricant containing a monoor polyurea thickening agent.--

Column 1, line 27, "compositiions" should read --compositions-- Column 2, line "in mixture" should read --or mixture-- Column 2, line "oil-soluble" should read --oil-insoluble-- U3, "monoor" should read mono-or-- Column 8, line Column 8, line "mono-and" should read --monoor- Signed and Sealed this sixteenth D ay 0f March 19 76 [sup] A ttes t:

C. MARSHALL DANN Commissioner oj'Patents and Trademarks RUTH C. MASON Arresting Officer

Claims

1. A GREASE COMPOSITION COMPRISING A MAJOR PART OF LUBRICATING OIL CONTAINING (1) FROM 0.5 TO 10 WEIGTH PERCENT OF A THICKENER SELECTED FROM MONO- OR POLYUREA COMPOUNDS OR A MIXTURE OF MONO- OR POLYUREA COMPOUNDS HAVING AN AVERAGE FROM 1 TO 8 UREIDO GROUPS AND HAVING A NUMBER AVERAGE MOLECULAR WEIGHT BETWEEN ABOUT 375 AND 2,500; AND (2) FROM 3 TO 30 WEIGHT PERCENT OF AN ALKALINE EARTH METAL CARBONATE.

3. The composition defined in claim 2, wherein said mono- or polyurea compound or mixture of mono- and/or polyurea compounds has an average of 3 to 4 ureido groups and has a number average molecular weight between about 600 and 1,200, and wherein said lubricating oil is a hydrocarbon oil.

4. A grease composition comprising a major portion of an oil of lubricating viscosity, from 3 to 30 weight percent of an alkaline earth metal carbonate and a mono- or polyurea compound or mixture of mono- and/or polyurea compounds prepared by reacting the following components: I. a diisocyanate having the formula OCN-R-NCO, wherein R is a hydrocarbylene having from 2 to 30 carbons; II. a polyamine having a total of 2 to 40 carbons and having the formula:

6. The composition defined in claim 5 wherein the molar ratio of diisocyanate to diamine to monoamine is 2:1:2.

8. The composition defined in claim 4 wherein said polyamine is a triamine.

10. The composition defined in claim 4 wherein said polyamine is piperazine.

16. The composition defined in claim 15 wherein said monoamine is oleyl amine.

17. A method for preparing a grease composition which comprises: I. admixing a C4 to C32 diisocyanate, a C2 to C40 polyamine and a C1 to C30 monoamine within a major portion of a lubricating oil, the molar ratio of diisocyanate to polyamine to monoamine being 1:0-2:0.1-2; II. maintaining said admixture at a temperature of 60* to 320*F. for a period of 0.5 to 10 hours; III. thereafter adding an alkaline earth metal hydroxide or oxide to said admixture; IV. contacting said admixture with 0.1 to 10 molar parts of carbon dioxide per molar part of alkaline earth metal base; and (V) thereafter milling said admixture to the consistency of grease.