US3506573A - Greases containing a hydrogenated olefin polymer vehicle,organophilic clay thickener and calcium acetate dispersion - Google Patents

Description

United States Patent US. Cl. 25221 12 Claims ABSTRACT OF THE DISCLOSURE Improved greases, having wide temperature utility, good oxidation stability, extreme pressure and anti-wear properties, are provided comprising a hydrogenated olefin polymer vehicle, a grease-forming quantity of a thickening agent comprising an organophilic clay, calcium acetate and a N-acyl-substituted sarcosine as a dispersing agent for the calcium acetate.

CROSS-REFERENCE TO RELATED APPLICATION Contiuation-inpart of Ser. No. 449,634, filed Apr. 20, 1965, now abandoned.

BACKGROUND OF THE INVENTION Field of the Invention This invention, which is a continuation-in-part of application Ser. No. 449,634, filed Apr. 20, 1965, relates to grease compositions and, in one of its aspects, relates to improved grease compositions which are suitable for use over wide-temperature ranges and which exhibit good oxidation stability, extreme pressure and anti-wear properties, and low starting and running torques under varying operational conditions. More particularly, in this respect, the invention relates to improved grease compositions which contain a combination of certain hydrogenated olefin polymer vehicles, organophilic clay thickening agents and extreme pressure agents in the form of calcium acetate in a dispersed state, which render these greases particularly effective in operations in which the aforementioned conditions are normally encountered.

Description of the prior art Greases heretofore prepared by theprocesses of the prior art have generally comprised a vehicle, such as petroleum hydrocarbon lubricating oils, refined mineral oils, or synthetic esters, in which various thickening agents, such as metal salts or soaps, are dispersed in grease-forming quatities in such degree as to impart to the resulting grease composition the desired consistency. In addition,

the use of extreme pressure agents, such as calcium acetate, has also been suggested for incorporation in a variety of conventional grease formulations. In this respect, the use of olefin polymers has heretofore been suggested as vehicles for grease formulations. It has been found, however, that while greases containing olefin polymer vehicles can perform satisfactorily at relatively high temperature ranges, while exhibiting a minimum effect with respect to deterioration of sealant materials, nevertheless, such greases have not been found to exhibit a concomitant gOOd oxidation stability. Thus, the ability to prepare a grease formulation in which each of the aforementioned characteristics is present, viz, reduced deterioration of sealant materials and good high temperature performance as well as low starting and running torques at sub-zero temperatures is highly desirable from a commercial standpoint. Insofar as thickening agents are concerned, the use of clay 3,506,573 Patented Apr. 14, 1970 ice thickeners has also been suggested for grease formulations. It has been found, however, that clay thickening agents, in a wide variety, have not exhibited the desired degree of penetration or minimum leakage or slumping, as evidenced by the standard ASTM Wheel Bearing Test. In this respect, greases employing certain clay-type thickeners are found to be semi-fluid, even though relatively large amounts of thickener are employed, and exhibit excessive bleeding and slumping when subjected to the aforementioned wheel hearing test. Furthermore, the use of an extreme pressure agent, such as calcium acetate, as an additional component, involves further difiiculty with respect to the problem of maintaining the extreme pressure agent in a dispersed state. It will, therefore, become apparent that improved grease compositions, which are thermally stable over wide temperature ranges, and which possess good oxidation stability, improved anti-wear and extreme pressure properties and good low temperature properties are highly desirable.

SUMMARY OF THE INVENTION In accordance with the present invention, as more fully hereinafter described, it has been found that improved grease compositions having wide temperature utility, good oxidation stability and reduced effect on sealants, together with improved extreme pressure and anti-wear properties, can be produced by employing, as the lubricating vehicle, a hydrogenated olefin polymer, in which the polymer has been prepared from olefins having from about 5 to about 18 carbon atoms per molecule, and preferably from about 9 to about 11 carbon atoms per molecule, and by employing as the thickening agent an organophilic clay, together with calcium acetate, as an extreme pressure agent, in combination with a N-acyl-substituted sarcosine compound (as more fully hereinafter described) in an amount sufficient to maintain the calcium acetate in a dispersed state. Greases prepared in this manner have been found to be superior, especially, with respect to wide temperature range utility, extreme pressure or load-carrying and anti-wear properties, as compared with the use of conventional greases which contain petroleum hydrocarbons, lubricating oils, refined mineral oils, or synthetic ester-type fluids as the vehicle, conventional soap-type thickeners, and calcium acetate as anextreme pressure agent.

As indicated above, the greases of the present invention are prepared from olefin polymers having from about 5 to about 18 carbon atoms per molecule. In general, these olefin polymers possess a relatively high viscosity index of at least about and can be produced by employing various polymerization procedures and catalytic agents. Thus, for example, a straight-chain or a branched-chain olefin having from about 5 to about 18, and preferably from about 9 to about 11 carbon atoms per molecule, may be polymerized in the presence of a suitable polymerization catalyst, for example, those disclosed in US. Patent 3,149,178. The use of the aforementioned polymerization technique is particularly applicable to the production of polymers prepared from olefins having from about 9 to about 18 carbon atoms per molecule.

Another polymerization technique for producing the polymer vehicles of the improved greases of the present invention, involves polymerizing a normal, alpha-monoolefin with a di-tertiary alkyl peroxide catalyst. Thus, for example, the olefins contemplated for this purpose may comprise normal alpha-monoolefinic hydrocarbons having from about 5 to about 14 carbon atoms, and preferably from about 7 to about 12 carbon atoms per molecule. In this technique particular applicability is contemplated with respect to the use of normal olefinic hydrocarbons having a double bond adjacent the terminal carbon atom, such as pentene-l, hexene-l, heptene-l,

octene-l, decene-l, undecene-l, dodecene-l, and tetradecene-l. The di-tertiary alkyl peroxide catalyst may be represented by the formula ROOR', in which R and R are the same or dissimilar tertiary alkyl radicals. Examples of this type of catalyst are di-tertiary butyl peroxide, di-tertiary amyl peroxide, and tertiary-butyl tertiary-amyl peroxide. The aforementioned polymerization technique is more fully described in US. Patent No. 2,937,129. As more fully hereinafter discussed, it has been found that if the hydrogenated olefin polymer is prepared from olefins having less than about carbon atoms per molecule, the resulting grease composition will tend to deteriorate rapidly at elevated temperature due to loss of vehicle by volatilization. On the other hand, it is found that if the hydrogenated olefin polymer is prepared from olefins having more than about 18 carbon atoms per molecule, the resulting grease composition will not exhibit suitable low-torque values at relatively low temperatures.

With reference to the organophilic clay thickening agent, various types of these clays may be employed. Particularly preferred are organophilic clays which contain predominantly aliphatic quaternary ammonium groups. In this respect, it has been found that if aliphatic quaternary ammonium groups predominate, relatively smaller quantities of the clay thickeners are required for producing an effective grease composition.

As previously indicated, in preparing the improved grease compositions of the present invention, the aforementioned olefin polymer vehicle is combined with the calcium acetate and the N-acyl-substituted sarcosine compound in an amount sufficient to maintain the calcium acetate in a dispersed state.

The N-acyl-substituted sarcosines used herein conform to the formula:

wherein R represents an aliphatic hydrocarbon radical having from about 8 to about 24 carbon atoms and which radical may be either saturated or unsaturated. Typical examples of these sarcosines are the following: N-pelargonyl sarcosine; N-undecyloyl sarcosine; N-lauroyl sarcosine; N-myristoyl sarcosine; N-palmitoyl sarcosine; N- stearoyl sarcosine; N-oleoyl sarcosine; N-linoleoyl sarcosine; N-arachidoyl sarcosine; N-behenoyl sarcosine; and N-hyenoyl sarcosine.

A number of the N-acyl-substituted sarcosines are available commercially under the tradename Sarkosyl, for example, Sarkosyl-L (N-lauroyl sarcosine), Sarkosyl-O (N-oleoyl sarcosine), and Sarkosyl-S (N- stearoyl sarcosine).

Either anhydrous or hydrated calcium acetate may be employed in forming the dispersions used herein. The calcium acetate can either be preformed or it can be formed in situ. When using preformed calcium acetate, the dispersion is prepared by forming a mixture of the acetate, the N-acyl-sarcosine and the base oil and stirring the mixture for a short period, for example, from a feW seconds up to about 30 minutes at a temperature of from about 25 C. to about 200 C. and preferably from about 50 C. to about 150 C. although stable dispersions can be formed at room temperature with only a brief initial mixing of the calcium acetate, the sarcosine compound and the oil and allowing the mixture to stand for several hours, their formation is considerably hastened by heating and stirring the mixture. Also, if desired, the mixture can be subjected to a mechanical homogenization treatment, although this step is not essential.

The calcium acetate can be prepared in situ by neutralizing calcium oxide or calcium hydroxide with either acetic anhydride or acetic acid in the presence of the oil and then heating the mixture to a temperature sufiicient to remove any free Water therefrom, i.e., above 100 C.

The N-acyl-sarcosine is then added and the dispersion formed as in the case of of the preformed calcium acetate.

As hereinbefore indicated, the above-described hydrogenated olefin polymer vehicle is combined with a greaseforming quantity of the organophilic clay to produce the novel grease compositions of the present invention, in which it is preferred that organophilic clay thickeners be employed which contain predominantly aliphatic quaternary ammonium groups. Thus, representative organophilic clays which predominate in aliphatic quaternary ammonium groups include dimethyl, ditallow ammonium bentonite clays, or mixtures of dimethyl, benzyl-tallow ammonium bentonite clays and dimethyl, ditallow ammonium bentolite clays. Other organophilic clays which do not contain predominantly aliphatic quaternary groups may also be employed as thickeners, as for example, dimethyl, benzyl-tallow ammonium bentonite clays. However, higher concentrations of these modified clays must be employed to thicken the hydrogenated olefin polymer vehicle to produce the desired grease.

The organophilic clays employed as thickeners in the grease compositions of the present invention, are characterized as modified clays, originally exhibiting a substantial base-exchange capacity (of at least 25) in which the exchangeable inorganic cation has been replaced by an onium base of such configuration as to make the surface of the clay particle organophilic and to an extent sufficient to form an onium clay having a substantial gelling characteristic in the polymer vehicle.

The clays which are useful as starting materials for making the modified clay in accordance with this invention are those exhibiting substantial base-exchange properties, and particularly those exhibiting comparatively high base-exchange properties and containing cations capable of more or less easy replacement. The clays particularly contemplated include the montmorillonites, viz, sodium, potassium, lithium and other bentonites, particularly of the Wyoming type; magnesium bentonite (sometimes called hectorite) and saponite; also nontronite and attapulgite, particularly that of the Georgia-Florida type. These clays, characterized by an unbalanced crystal lattice, are believed to have negative charges which are normally neutralized by inorganic cations, as found in nature, therefore, they exist as salts of the weak clay-acid with bases such as the alkalior alkaline-earth metal hydroxides.

The base-exchange capacities of the various clays enumerated run from about 25 to about 100, based up n milliequivalents of exchangeable base per grams of clay. The montmorillonites have comparatively high baseexchange capacities, viz, 60-100. Attapulgites have substantial base-exchange capacity, viz, 2535. Generally, the clays of higher base-exchange capacities are particularly useful Where high exchange of an organic base for the cation of the clay is desired.

More specificially, and in accordance with illustrative embodiments of this invention, a clay of the character described and exhibiting substantial base-exchange capacity, is reacted with an organic compound, more particularly generally defined to as an onium compound, by the substitution for the clay cation of the cation of the organic compound, which cation is of a class referred to as an onium base. The present greases are not, however, restricted to the use of a reaction product of a base-salt with clay-salt, but includes the reaction product of a free base with an acid-clay.

An onium compound has been defined in Hackhs Chemical Dictionary, Second edition, as A group or organic compounds of the type RXH, which are isologs of ammonium and contain the element X in its highest positive valency, viz:

Where X is pentavalent as in ammonium, phosphonium, arsonium, and stibonium; where X is tetravalent as in oxonium, sulfonium, seleonium and stannonium compounds; and where X is trivalent, as in iodonium compounds; and that they may be considered addition compounds of oxonium, carbonium, stibonium, c.f., -inium, -ylium.

A number of compounds are capable of reacting with clays, particularly bentonite; it is to be understood, however, that various other compounds reactiable with clays of the character described, may be employed. These compounds may include salts of aliphatic, cyclic, aromatic and heterocyclic amines, primary, secondary, and tertiary amines and polyamines, also quaternary ammonium compounds, as well as other monobasic or polybasic onium compounds, such as triphenylalkyl phosphonium or stibonium-halides, or dialkyl-, or diaryl-sulphonium and seleonium halides, and pyrones, such as 2,5-dimethyl gamma pyrone hydrochloride.

As previously mentioned, the untreated sodium bentonite in contact with water adsorbs large quantities of the water and swells, forming a gel. This swelling has been attributed to the lamellar structure of the clay mineral and to adsorption of water molecules onto the surfaces of the mineral sheets, thus giving rise to a separation of the sheets as the oriented water layers build up to an appreciable depth. If the surfaces of the clay laminae contain organic matter, as by the reaction of baseexchange with an organic base, the ability of water molecules to be adsorbed is eliminated, and the clay no longer exhibits its former swelling capacity in water. Thus, Wyoming bentonite, for example, which is essentially the sodium salt of montmorillonitic acid, is capable of reacting with organic bases or their salts, e.g.,

or more readily The resulting dodecylammonium bentonite is visualized as consisting of clay mineral laminae with dodecylammonium groups fairly regularly distributed over the surfaces and attached by means of the substituted ammonium groups, with the hydrocarbon tails extending out over the crystal surfaces. Such a material is now organophilic rather than hydrophilic and as such exhibits in organic liquids some of the characteristics which the untreated clay exhibited in water. For example, it will swell in many organic liquids and will form stable gels and colloidal dispersions. Such gels are visually homogeneous and often transparent or translucent. They are thermally stable up to the boiling point of the liquid phase and show little tendency to flow or run when heated. The more dilute systems which are more or less liquid have viscosities much higher than those of the liquids themselves, and in most cases exhibit thixotropy characteristic of the analogous bentonite-Water system.

The amount of the aforementioned N-acyl-substituted sarcosine compound present in the finished grease formulation, as previously indicated, is such quantity as is sufficient to maintain the calcium acetate in a dispersed state. In general, for many applications, the calcium acetate is employed in an amount from about 1 to about 20 percent, and preferably from about 2 to about 6 percent, based on the total weight of the grease composition. correspondingly, in such formulations, the N-acyl-substituted sarcosine compound generally required to maintain the calcium acetate in a dispersed state, is in an amount from about 0.05 to about 2.0 percent, and preferably from about 0.1 to about 0.5 percent, based on the total weight of the grease composition.

6 DESCRIPTION OF THE SPECIFIC EMBODIMENTS The following data and examples will serve to illustrate the improved grease compositions of the present invention and their properties, with the parts recorded, being understood as recorded in parts by weight. In order to illustrate the markedly improved results obtained by employing, as the vehicle of the novel grease compositions, a hydrogenated olefin polymer, prepared from olefins having from about 5 to about 18 carbon atoms per molecule, a series of grease compositionswere prepared, for comparative purposes. In the following Table I, Examples 2, 4 and 8 are illustrative of the improved greases that are obtained, utilizing the aforementioned hydrogenated olefin polymers, as previously described, as the fluid component or vehicle, employing both conventional type nonclay thickeners as well as the organophilic clay thickeners of the present invention. The greases in Examples 2, 4 and 8 are thus compared with conventional-type greases, which do not employ the hydrogenated olefin polymer vehicles of the present invention, as illustrated by Examples 1, 3, 5, 6-, 7 and 9.

Example 2 illustrates a synthetic hydrogenated hydrocarbon polymer vehicle, viz, polydecene-l (Polymer A), prepared in accordance with the processes described in the aforementioned US. Patent No. 3,149,178, employing AlCl as the catalyst. As the example discloses, this polymer vehicle is thickened with a calcium-complex soap.

Example 4 illustrates a synthetic hydrogenated hydrocarbon polymer vehicle, viz, a polydecene-l (Polymer B), prepared in accordance with the process described in the aforementioned US. Patent No. 3,149,178, employing BF as the catalyst. This polymer is thickened with an organophilic clay thickener and may be compared with Example 3, showing the same thickener employed with a conventional-type ester fluid. It will be noted that the grease of Example 4 exhibits superior running torque at 65 F., rubber swell, and high temperature performance at 350 F., and has comparable consistency, evaporation and starting torque properties.

The greases of Examples 6, 7 and 9 may be compared with the grease of Example 8 to show the superiority of the latter. The grease of Example 8 is the only grease which, simultaneously, exhibits a low rubber swell, low torque at -65 F., and low evaporation at 350 F. The other greases of Examples 6, 7 and 9 may exhibit one or more of these desirable properties, but not all of them. This is clearly indicative of the unexpected superiority of the greases of the present invention over conventionaltype grease prepared from esters, diesters, mineral oils, and polybutenes, as examples of conventional vehicles of the prior art. Polymer A of Example 2 has a viscosity of 10.52 cs. at 210 F. viscosity. Polymer B of Examples 4 and 8 has a viscosity of 4.32 cs. at 210 F. viscosity.

' The manufacturing procedure employed in preparing the greases of Examples 1 and 2 comprises adding to a kettle approximately two-thirds of the fluid, the calcium acetate, calcium caprylate, and calcium stearate. This mixture is heated, with constant stirring, to a temperature of 450 F. Thereafter, the balance of the fluid is added and the resulting mixture is cooled to 200 F. The balance of the other ingredients is then added. The resulting mixture is then cooled, with constant stirring, to a temperature of about 180 F., and is then passed through a Tri Homo Colloid Mill at 0.002" setting.

The manufacturing procedure employed in preparing the grease of Examples 3, 4, 5, 8 and 9 comprises adding to a kettle about two-thirds of the fluid, the organophilic clay, and the stabilizer (pentaerythritol), which is dissolved in about 5 parts of Water. The resulting mixture is then heated, with constant stirring, to a temperature of 320 F. Thereafter, the balance of the fluid is added, and the resulting mixture is cooled, with constant stirring, to a temperature of about 200 F. The balance of the ingredients is next added and the resulting mixture is then cooled, with constant stirring, to a temperature of about 180 F. The product is then passed through a Tri Homo Colloid Mill at a 0.002 setting.

genated (unsaturated). Thus, it has been found that the grease compositions of the present invention which contain the hydrogenated C C olefin polymer vehicles exhibit outstandingly improved oxidation stability over the TABLE I Type of Fluid:

Polydeeene-l (Polymer A) (hydrogenated), parts Ester (Trimethylol Propiane Tricaprylate), parts. Polydeeene-l (Polymer (hydrogenated), parts-. Mineral Oil-Diester Blend, parts Mineral Oil, parts Polybntenc, parts Type of Thickencr:

Calcium complex soap p Non-soap thickener (Bar-agel clay & stabilizer) parts Lithium Soaps, parts Type of Antioxidant:

Amine type, parts Phenol type, parts Anti-rust additive, parts arts Properties of Fluid:

Viscosity index Evaporation loss at 350 F. (ASTM D972) (wt. pcreent) Pour point, F. (ASTM 97-52) Kinetic viscosity at 210 F., es. (ASTM D445)... Flazh point, F. (ASTM 92*57) Properties of Greases:

NLGI consistency grade Evaporation lo 5 at 300 F. (ASTM D. Evaporation 1065 at 3 0 F. (ASTM D07. Low temp. torque at -40 F. (AS'I M Starting Running Low temp. torque at -G5 F. (A

Start' Running Rubber swell. percent (Fed. Std. High temp. performance (Fed. Std 791 Method 331):

Endurance life at 350 F., hrs

Average, hours (wt. percent) D1478):

lei'iviethod abs 11. .IIIIII:

1 Calcium acetate monohydrate 11.0 parts, calcium caprylate 5 parts and calcium stearate 3.7 parts. 1 Baragcl clay comprises a mixture of dimethyl, benzyl-tallow ammonium bentonite clay and dimethyl, ditallow ammonium bentonite clay.

The superiority of the properties of the greases of the present invention, which contain the aforementioned hydrogenated olefin polymer vehicles over conventional-type greases which do not contain such vehicles, will, therefore, be apparent from a comparison of the examples described in the above Table I. It will be understood, however, that other hydrogenated olefin polymers may be substituted as the vehicle for those shown in the improved greases of Examples 2, 4 and 8, and prepared from olefins having from about 5 to about 18 carbon atoms per molecule.

As previously indicated, the novel grease compositions of the present invention employ a hydrogenated olefin polymer, prepared from olefins having from about 5 to about 18 carbon atoms per molecule. On a comparative basis, in this respect, it is found that a marked distinction exists between grease compositions which contain the aforementioned hydrogenated olefin polymers and greases which contain olefin polymers within the aforementioned C -C olefin polymer range, but which are non-hydrosame grease compositions which contain only non-hydrogenated (unsaturated) olefin polymer vehicles.

In order to demonstrate the aforementioned superiority of the greases of the present invention with respect to im proved oxidation stability, eight grease compositions containing both hydrogenated as well as unsaturated olefin polymer vehicles within the aforementioned olefin polymer range were evaluated with respect to oxidation stability, as determined by the standard ASTM bomb test D 942-50 for greases at 210 F.

As is shown in the following Table II, an evaluation was made with respect to determining criticality in oxidation stability for greases which contain the organophilic clay thickeners of the present invention, as well as greases containing non-organophilic thickeners, such as lithium hydroxy stearate, and with further respect to evaluating the oxidation stability of greases relative to both hydrogenated and unsaturated C polymers (polyhexene) and also hydrogenated and unsaturated C polymers (polydecene).

TABLE IL-ASTM BOMB TEST D942-50 FOR GREASES AT 210 F.

Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8

Gclling Agents (wt. percent):

Lithium hydroxy stcarate 10.0 10.0 10.0 10.0 Non-soap thickener (Baragel clay and stabilizer) 11.0 l1. 0 11. 0 11.0 Fluids (wt. percent):

Polyhexene, unsaturated 90.0 89. 0

Polyhexene, hydrogenated.

ASTM Bomb Test at 210 F. (D942-50) p.s.1.g.

drop per 24 hours 1 Baragel clay comprises a mixture of dimeth lay.

ditallow ammonium bentonite c yl, benzyl-tallow ammonium bentonite clay and dimethyl As will be noted from the foregoing Table II, when lithium hydroxide stearate was employed as the thicken- Thickener C does not contain predominantly aliphatic quaternary ammonium groups.

TABLE IIL-EFFECT OF THICKENER TYPE ON GREASE CONSISTENOY AND PE RFROM- ANCE IN THE ASTM WHEEL BEARING TEST Example N o.

Synthetic hydrocarbon 1 86. 47 86. 47 85. 30 Thickener A 9. Thickener B 9.00 Thickener C. 10. 00 Structure modifierG) 1. 53 1. 53 1. 70 E. P. additiveG) Antioxidants 3. 00 3. 00 3. 00 Dispersant for additivefl) 0.18 0. 18 0. 18 ASTM penetration unworked/worked 279/306 281/288 430/430-1- 261/273 273/270 430+/480+ ASTM wheel-bearing test (D-1263) 1g. 30+g. 1g. 10.5g.

1 Hydrogenated polydecene. Z Pentaerythritol.

3 Clacium acetate.

4 N-oleoyl sarcosine.

5 ASTM standards (1964) part 18, p. 515-521.

ing agent in combination with unsaturated polyhexene as a vehicle, the ASTM bomb test revealed a pressure drop of 100 p.s.i.g., as shown in Example 1. On a comparative basis, as shown in Example 3, the same grease in which the polyhexene vehicle was hydrogenated revealed a significantly improved pressure drop of only 97 p.s.i.g. It will also be noted that when a clay thickener was substituted for the lithium hydroxy stearate, as shown in Example 2, a pressure drop of 9-0 p.s.i.g. was obtained employing the unsaturated polyhexene vehicle. On the other hand, as is shown in Example 4, when hydrogenated polyhexene was substituted as the vehicle in this same grease composition, a pressure drop of 0 was obtained. Thus, it will be seen that the hydrogenated polyhexene vehicle in the same grease composition represents a marked improvement in diminished pressure drop over the same grease which contains the unsaturated polyhexene vehicle, as revealed by the standard ASTM bomb test.

Referring once more to the foregoing table, it will be noted that when lithium hydroxy stearate was employed as a gelling agent in combination with unsaturated polydecene as a vehicle, the ASTM bomb test revealed a pressure drop of 98 p.s.i.g., as shown in Example 5. On a comparative basis, as shown in Example 7, the same grease in which the polydecene vehicle was hydrogenated revealed a significantly improved pressure drop of only 64 p.s.i.g. It will also be noted that when the organophilic clay thickener was substituted for the lithium hydroxy stearate, as shown in Example 6, a pressure drop of 98 p.s.i.g. was obtained employing the unsaturated polydecene vehicle. On the other hand, as is shown in Example 8, when hydrogenated polydecene was substituted as the vehicle in this same grease composition, a pressure drop of 0 p.s.i.g. was obtained. Thus, it will be seen here also that the hydrogenated polydecene vehicle in the same grease composition represents a marked improvement in diminished pressure drop over the same grease which contains the unsaturated polydecene vehicle, as revealed by the standard ASTM bomb test.

As previously indicated, of the organophilic clay thickening agents of the present invention, clays are preferred in which the quaternary ammonium groups are aliphatic or predominantly aliphatic. As illustrative thereof, three organophilic clay thickeners were evaluated for their efiect in grease compositions, as shown in Table III. Thickener A comprised a dimethyl, ditallow ammonium bentonite clay. Thickener B comprised a mixture of didimethyl, ditallow ammonium bentonite clay. Thickener C comprised dimethyl, benzyl-tallow ammonium bentonite clay. Thus, it will be noted that in thickener A, the quaternary ammonium groups are aliphatic and in thickener B, the quaternary groups are predominantly aliphatic.

Examples 1, 2 and 3 in the above Table III, represent non-extreme pressure greases, in which the only diflerence resides in the particular organophilic clay thickener. It will be noted from the table that comparable penetrations are obtained with 9% of either thickener A or thickener B and little or no leakage or slumping in the ASTM Wheel Bearing Test. With respect to thickener C, it will be noted that the grease was semi-fluid even though 10% thickener had bee used. This grease exhibited excessive bleeding and slumping in the wheel bearing test.

Examples 4, 5 and 6, in the above Table III represent extreme pressure greases which demonstrate the same distinction as exemplified in the comparison of the nonextreme pressure greases of the foregoing Examples 1, 2 and 3. In this respect, it was found in a subsequent test, that by increasing the quantity of thickener C to 15%, still produced an ASTM penetration of 390. At least 20% of thickener C is, therefore, required to obtain penetrations in the desired 280-300 range.

In order to demonstrate the improved load-carrying ability realized in formulating the novel grease compositions of the present invention which, in combination with the hydrogenated olefin polymer vehicle and organophilic clay thickener, and extreme pressure agent, viz, calcium acetate and an N-acyl-substituted sarcosine dispersant, is employed, the following camparative data were obtained.

EXAMPLE I A base grease formulation was prepared in the following manner: a synthetic hydrogenated hydrocarbon polymer, viz, polydecene-1, prepared in accordance with the processes described in U.S. Patent No. 3,149,178, was employed as the lubricating vehicle. This polymer had the following characteristics:

Viscosity index 134 Pour point, F. (ASTM 97-52) 65 Kin. visc. at 100 -F. cs. (ASTM D445) 31.7 Flash point, F. (ASTM 9257) 445 83.2 parts, by weight, of the above-described hydrogenated polydecene-1, as the lubricating vehicle, was combined with 10 parts, by weight, of Baragel, (a mixture of dimethyl, benzyl-tallow ammonium bentonite clay and dimethyl, ditallow ammonium bentonite clay); 1.7 parts, by weight, of pentaerythritol, as a stabilizer; 3 parts, by weight, of a mixture of p,p' di-octyl diphenyl amine and a hindered phenol, as an antioxidant; and 2.1 parts, by weight, of a mixture of NaNO and the recation product of glycine and tetrapropenyl succinic anhydride, as an anti-rust additive.

1 1 EXAMPLE H A dispersion of calcium acetate and an N-acyl-substituted sarcosine compound was prepared in the following manner: 565 parts, by weight, of the hydrogenated polydecene-l, employed as the lubricating vehicle in Example I, above, was charged to a grease kettle. 35 parts, by weight, of N-oleoyl sarcosine was then added, and the resulting mixture was stirred for a period of about 15 minutes. 400 parts, by weight, of calcium acetate was then added to the kettle over a 30-minute period, with stirring. The resulting mixture was then slowly heated to 280 F., and the cooled to room temperature. The resulting product thus represented a 40 percent dispersion of calcium acetate.

EXAMPLE III A blend was prepared comprising 95 parts, by weight, of the base grease formulation, of Example I, and 5 parts, 'by weight, of the calcium acetate dispersion of Example II. This grease formulation was then tested for load-carrying ability by means of the standard Rock Island Arsenal Procedure for Modified Mean Hertz Load. This standard method is an abbreviated version of Method 6503 of Federal Test Method Standard No. 791a, Dec. 13, 1961. In accordance with this procedure, the tests were conducted in the standard 4-Ball E.P. Tester. The tests performed on the base grease formulation of Example I, revealed a Mean Hertz Load value of 28; while the tests performed on the grease blend of Example III, containing the above-described calcium acetate dispersion, revealed a Mean Hertz Load value of 34.7.

EXAMPLE IV A blend was prepared comprising 97 parts, by weight, of the base grease formulation of Example I and 3 parts, by weight, of the calcium acetate dispersion of Example II. This grease formulation was then tested for loadcarrying ability in accordance with the test described in Example III and revealed a Mean Hertz Load value of 33, as compared with a value of 28 for the base grease formulation of Example I.

EXAMPLE V A blend was prepared comprising 90 parts, by weight, of the base grease formulation of Example I and parts, by weight, of the calcium acetate dispersion of Example II. This grease formulation was then tested for load-carrying ability in accordance with the test described in Example III and revealed a Mean Hertz Load value of 39, as compared with a value of 28 for the base grease formulation of Example I.

The superiority of the properties of the novel grease compositions of the present invention over conventionaltype greases wil be apparent from a comparison of the representative data set forth in the above examples. In general, it will be noted, that the aforementioned comparative examples and data disclose that improved greases can be prepared whichcomprise an eifecitve combination of the specified hydrogenated olefin polymer vehicle, organophilic clay thickeners, employing as an extreme pressure agent calcium acetate with the abovedescribed N-acyl-substituted sarcosines as dispersing agents. It will be understood, also, that other hydrogenated olefin polymers may be substituted for those shown in the above examples as the vehicles, and prepared from olefins having from about 5 to about 18 carbon atoms .per molecule. In addition, other N-acyl-substituted sarcosines may be employed for obtaining the aforementioned dispersion of calcium acetate in the improved grease formulation, as her'einbefore indicated. Also, as has been previously indicated, other organophilic type clays may be employed as thickeners. It should also be noted, that if so desired, it is possible to blend these improved greases with conventional-type greases for the purpose of upgrading the quality level of the latter. Furthermore, it is also within the scope of the invention to incorporate in these greases additional additives or other characterizing materials and fillers, if so desired. For example, the grease can contain antioxidants, such as amines (e.g., phenyl alpha-naphthylamine), phenols (e.g., 2-6-di-tertiary butyl-4-methyl phenol), and the like; lubricity improving agents such as free fat, free fatty acids, esters of alkyl and/or aryl, sulfurized fats, molybdenum disulfide, lead soaps, and the like. Other additives may also be included for imparting anti-wear, anti-rust and extreme pressure properties, if so desired.

While preferred embodiments of the novel grease compositions of the present invention, and the method for their preparation, have been described for purposes of illustration, it will be understood that various modifications and adaptations thereof, which will be apparent to those skilled in the art, may be made without departing from the spirit of the invention.

We claim:

1. A grease composition comprising: a hydrogenated olefin polymer vehicle, said polymer having been prepared from an olefin having from about 5 to about 18 carbon atoms per molecule; a grease-forming quantity of a thickening agent comprising an organophilic clay; calcium acetate in an amount sufficient to impart extreme pressure properties; and, in an amount sufficient to maintain said calcium acetate in a dispersed state, a N-acylsubstituted sarcosine compound of the formula:

where R represents an aliphatic hydrocarbon radical of from about 8 to about 24 carbon atoms.

2. A grease composition as defined in claim 1, in which said olefin polymer is prepared from olefins having from about 9 to about 11 carbon atoms per molecule.

3. A grease composition as defined in claim 1, in which the thickening agent comprises an organophilic clay containing predomiantly aliphatic quaternary ammonium groups.

4. A grease composition as defined in claim 1, in which the organophilic clay comprises a dimethyl, ditallow ammonium bentonite clay.

5. A grease composition as defined in claim 1, in which the organophilic clay comprises a mixture of dimethyl, 'benzyl-tallow ammonium bentonite and dimethyl, ditallow ammonium bentonite clays.

6. A grease composition as defined in claim 1, in which the organophilic clay comprises a dimethyl, benzyl-tallow ammonium bentonite clay.

7. A grease composition as defined in claim 1, in which the sarcosine compound is oleoyl sarcosine.

8. A grease composition as defined in claim 1, in which the sarcosine compound is stearoyl sarcosine.

9. A grease composition as defined in claim 1, in which the sarcosine compound is lauroyl sarcosine.

-10. A grease composition as defined in claim 1, in which the calcium acetate is present in an amount from about 1 to about 20%, and the sarcosine compound is present in an amount from about 0.05 to about 2% based on the weight of the total grease composition.

11. A grease composition as defined in claim 1, in which the calcium acetate is present in an amount from about 2 to about 6%, and the sarcosine compound is present in an amount from about 0.1 to about 0.5% based on the weight of the total grease composition.

12. A grease composition as defined in claim 1, in which the vehicle comprises hydrogenated polydecene, the thickening agent comprises a dimethyl, ditallow ammonium bentonite clay, and the sarcosine compound is oleoyl sarcosine.

(References on following page) Doherty 252-59 Stros-s 252-28 Peterson 252-28 Peterson et a1 252-28 Garwood 208-18 Dyer 208-18 Sauer 252-59 Davis 252-515 5 DANIEL E. WYMAN, Primary Examiner I. VAUGHN, Assistant Examiner US. Cl. X.R.

'zg g UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,506, 573 D d April 1 4, 1970 Inventor(s) Richard A. Butcosk and John J. Giammaria.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Co1umn 5, line n, for "+C12O25NH2H'+OH'" read Column 6, line 51, for "grease" read --greeses-- Column 9, line 69, for "di-dimethyl, ditallow ammonium bentonite clay" read --dimethy1, benzyl-tallow ammonium bentonite clay and dimethyl, ditallow ammonium bentonite ole Column 10, Table III, for "clacium" read--calcium-- Column 10, line 32, for "has" read --been-- Column 11, line 12, for "the" read --then-- 3IGNED AND SFMFU AUG 2519170 (SEAL) Atlost: I

mama m. mm Itmm x." m.

Gamissioner of Penn Aucstingofim