US2828260A

US2828260A - Table iv

Info

Publication number: US2828260A
Authority: US
Publication date: 1958-03-25
Anticipated expiration: 1975-03-25

Description

INORGANIC GEL-THICKENED LUBRICANT OF GOOD TEMPERATURE SUSCEPTIBILITY AND ggqNgMIC WATER STABILITY CHARACTER- Ernest C. Milberger, Maple Heights, Ohio, assignor to The Standard Oil Company, Cleveland, Ohio, :1 corporation of Ohio No Drawing. Application February 8, 1954 Serial No. 409,006

6 Claims. (Cl. 252-28) This invention relates to an aerogel thickened lubricantresistance 'teriorate readily in the presence of water, presumably due to the high solubility of the soda base soap in water. Calcium soap greases have better resistance to water but tend to lose their consistency or thin out at 2,828,260 Patented Mar. 25, 1958 2 excellent temperature susceptibility properties and ex cellent dynamic water-resistance, attributable to the presence of the alkylol or amino imidazoline and the polyalkylene glycol diether.

The polyalkylene glycol diethers are characterized by the following general formula:

R[?O?CHR1[CHR2]1|*]OR3 where n is an integer having the'value of'one or more, preferably one, two or three, x is an integer taken in sufiicient number to produce an ether having the prescribed viscosity, R and R are hydrogen or lower alkyl groups, and R and R are each lower alkyl groups. When n is one, preferably at least one of R and R is a lower alkyl group, preferably methyl. The lower alkyl group can have from one to about five carbon atoms such as methyl, ethyl, propyl, butyl or amyl and can have either a straight or branched chain. Preferably, one of R and R is hydrogen one is a methyl group, and R and R can be, methyl, ethyl'or isopropyl.

Within the above Formula 1 and worthy of especial mention are the mixed ethers of the types:

elevated temperatures. Both types of soap base greases where a, b, and. x are integers taken in suflicient numbreak down at temperatures of the order of 300 to 400 F. and this breakdown is accompanied by an irreversible change in the grease structure so that on cooling the grease is found to have lost its greaselike characteristics. The aerogel greases usually are far superior to the soap base greases in stability at high temperatures as the following'table shows:

However after heating at high temperatures some aerogel greases tend to thin out-upon stirring and this is undesirable in field applications where a grease, is agitated'or worked while subject to a high temperature. Aerogel greases also reveal an unsatisfactory dynamic water resistance and this again is unsatisfactory in field applications where the grease is agitatedor worked in the presence of water. a The grease may emulsify with water to the point of inversion to an oil-in-water emulsion, at which point the grease characteristics are lost.

In accordance with the invention water-insoluble oilmiscible or -dispersible polyalkylene .glycol diethers characterized by a viscosity-at 100 F. within the range of 40 to 500 SSU are employed in conjunction with an alkylol or amino imidazoline in thickened lubricant-compositions comprising a lubricating oil thickened with a nonabrasive inorganic thickening or filling agent and particularly finely divided silica, a silica aerogel being illustrative. The thickened lubricants so prepared have her to produce .an ether having the prescribed viscosity, an n and 1 and 1. and R2 and. R2. cann e th same or different, and are defined as in Formula 1. Preferably, when the a units are OCH CH and the b units OCH2CH ZHs the ratio of azb is to 25 of a to 10 to of b.

These ethers are obtained by reaction of the alkylene oxide with water or a glycol, and with a monohydric alcohol, desirably in the presence of a catalyst. The reaction which takes place seems to be a simple addition wherein the alkylene oxide is converted to the corresponding oxyalkylene groups or radicals. The glycol may itself be prepared by reaction of the alkylene oxide with water. Thus, water can be regarded as the ultimate starting material. The molecular weight of the polymer obtained will depend upon the relative proportions of alkylene oxide, water and nionohydroxy aliphatic alcohol.

From various analyses it has been determined that these polyalkylene glycol others are complex mixtures of .compounds having polyoxyalkylene chains of different lengths and difierent internal configurations, and although the materials are characterized as diethers, theymay contain a small'proportion of chains having hydroxyl groups at each end and of chains having one alkyl group at-each end, i. .e., monoethers. If mixed alkylene oxides are employed as the starting material the chains will contain complex mixtures of the mixed alkylene oxide radicals in various combinations, depending upon the relative proportions of the alkylene oxides, and a given chain may have several oxyalkylene units of the same type together orintermingle with othe xyal yl n u its in any o e or-combination. Thusthe above formulae for the mixed ethers are merely suggestive of the types of combinations t may b f n The imp rtant cri erion rom th andp in o the invention isthe viscosity of the ether, and this should be within the range from 40 to 500 SSU at F.

Polyethylene and mixed polyethylene-1,2-propylene glycol dimethylethersare preferred.

Thus it will be understood that there can be employed in accordance with the invention mixtures of these glycol others with monohydroxy monoethers and even dihydroxy compounds which are present in the mixture following condensation and/ or etherification of the alkylene oxide, but at least the major proportion and preferably upwards of 85% is the diether. Reference is made to U. S. Patent No. 2,425,845, to Toussaint et 211., dated August 19, 1947, which describes methods for the manufacture of the glycols and to U. S. Patent No. 2,425,755, to Roberts et al., dated August 19, 1947, which describes the preparation of the monoethers. The diethers are obtained by methodsanalogous to the monoethers, using twice the amount or more of the monohydric alcohol.

The imidazoline should be surface-active, oil-dispersible and water-insoluble and has the following structure:

Many of the compounds having the above general structure are also capable of improving the high temperature stability of lubricating oils thickened with inorganic thickening or gelling agents, such as silica aerogels.

In the above formula, R is a hydrophilic group. Especially satisfactory hydrophilic groups are alkylol groups and aliphatic, cycloaliphatic or mixed cycloaliphatic amino groups having at least one basic nitrogen atom.

The alkylol group can bear one or more hydroxyl groups.

The amino group preferably has at least two basic nitro .gen atoms, which can be primary, secondary or tertiary, in any combination of the three. Where one or more of the nitrogens is primary, i. e., NH they can be attached at any position in an aliphatic chain or on a cyclic ring. Where one or more of the nitrogens is secondary or tertiary, i. e.,

they can be substituted in a straight or branched aliphatic .chain, or in heterocyclic ring, which can itself bear alkyl, alkylene, hydroxyalkyl or hydroxyalkylene groups, desirably in the 'l-position, as in the above imidazoline ring. See U. S. Patent No. 2,655,476, dated October 13, 1953, to Everett C. Hughes and Ernest C. Milberger.

Thus R can be a hyd-roxyethyl group, a mono-, dior triethylene amino group, a l-alkylene-imidazoline group, or a l-alklylene amino imidazoline group.

R is an alkyl, hydroxyalkyl, alklyene or hydroxyalkylone group.

R, which is derived from an acid, can have from eleven to twenty-one carbon atoms, such as undecyl, tridecyl, abietyl, pentadecyl, undecenyl, heptadecyl, ricinoleyl, and heptadecenyl.

The alkylol irnidazolines are prepared by reaction of.

aliphatic acids and hydroxy diamines followed by cyclization, in the following way:

:a'ooou RNHCH CHgNH; n-1v N 21120 non-abrasive.

line, and analogous compounds as described in application Serial No. 240,452, filed August 4, 1951, now U. S. Patent No. 2,711,393, patented June 21, 1955, have been found to be particularly effective alkylol imidazolines in the thickened lubricants of the invention.

The amino imidazolines are prepared by reaction of aliphatic acids and polyamines followed by cyclization in the following way:

Amino imidazolines in'which R has two basic nitrogen atoms and from four to about twenty carbon atoms, such as diethylene'diamino and triethylene triamino, and the alkyl-substituted N-alkylene and N-alkyleneamino imidazolines (wherein R is attached to the imidazoline nucleus of the general formula through the N-alkylene or Nalkylene-amino group), are readily available and are preferred. The chain length for R is dependent upon the basic (polar) character of the group, the larger the number of carbon atoms, relative to the number of amino nitrogens, the more the group takes on the character of a hydrocarbon'and loses its basic or amine character. An upper limit of about five carbon atoms per amino nitrogen is indicated by this requirement, with about a maximum of thirty carbon atoms for the R group.

The amino imidazolines described in U. S. Patent No. 2,655,476 have been found to be particularly effective in the thickened lubricants of the invention.

The presence of the polyalkylene glycol ether in an amount to obtain improved high temperature and dynamic water stability does not markedly aifect the consistency of the thickened lubricant, i. e., the amount of the inorganic gelling agent to impart a given consistency to the thickened lubricant is not materially modified. Furthermore, the inclusion of the polyalkylene glycol ether will not efiect a change in the consistency of the thickened lubricant upon storage.

Due to the inorganic nature of the gelling agent, the thickened lubricant has excellent storage stability. This is to be contrasted with the heat susceptibility and deterioration of fatty materials in soap-base greases.

The preparation of the grease is simple and readily adaptable to continuous operation, as contrasted with the involved grease-making techniques which are often considered in the industry as an art.

The oil stock used in making the thickened lubricant may be widely varied, as contrasted with present greasemaking requirements in which the oil in many cases must meet certain critical specifications.

In addition, the avoidance of the use of soap permits :the manufacturer to be independent of the fat supply, which is important in periods in which fats and soaps are scarce and, many times, of pronounced non-uniformity.

The inorganic gelling agent to be used in making the thickened lubricant in accordance with this invention may be any inorganic material which forms a gel with a lubricating oil and which is so finely divided as to be The preferred materials are the aerogels, which may be formed from any material not incompatible with oil, such as silica, alumina, and other gel-forming metal oxides.

A series of silica aerogels which can be used as the inorganic gelling agent of theinvention are manufactured by Monsanto Chemical Company and marketed under the trade name Santocel. 7

Santocel Cis prepared from a sodium silicate solution sets to form a hydrogel. The by-product sodium sulfate is washed out by repeated washings with water. The continuouswater phase in this 'hydrogel is then replaced by continued Washing with alcohol until an alcogel is formed. In order to remove the liquid phase without a collapse of the gel structure, the alcogel is placed in an autoclave which is heated above the critical temperature of the alcohol and the pressure is allowed to increase to a point above the critical pressure of the alcohol. The vent valve is opened and the alcohol allowed to escape. Under these conditions, the silica gel structure remains practically undisturbed and the liquid phase of the gel is replaced with air. The material is then reduced in particle size by blowing it through a series of pipes containing sharp bends with jets of compressed air. Santocel C has a secondary agglomerate particle size of about 3 to 5 microns.

Santocel A is prepared as set forth for Santocel C up to the point of removal of the product from the autoclave. This material is run through a continuous heating chamber where it is heated for /2 hour to a temperature of about 1500 F. to eliminate the last traces of volatile material. It is then broken down in a reductionizer or micronizer to a particle size of about & inch in diameter. The solids content of the original hydrogel used in preparing Santocel C is approximately higher than that of Santocel A.

AR is a modification of A, differing only in that the material is reductionized to about the same particle size as C, approximately 1 to 6 microns in diameter.

ARD is a modification of AR, difiering only in that ARD is densified by extracting air under vacuum, and therefore has a smaller volume than AR.

AX is an A which has not been devolatilized.

CDv is a Cwhich has been devolatized as set forth for A. CDv is reductionized before being devolatilized.

CDvR differs slightly from CD; in that the CDvR has been devolatilized just after heating in the autoclave and then reductionized. It differs from CDv in that the latter is reductionized before being devolatilized.

The primary differences between the As and the Cs are as follows:

(1) The Cs are prepared from a'sodium silicate solution containing 25% more silica than the As. Therefore, in general the As are lighter and composedof smaller .particles than the Cs,

(2) The As have undergone a devolatilization step in their preparation.

The following are the bulk densities of preferred'silica aerogels:

Density, grams per ml.

AR 0.029 ARD 0.056 to 0.064 C 0.082

In general, AR and ARD show superior gelling ability and the As in general are better than the Cs. Silica aerogels which have been devolatilized generally have a higher gelling efliciency than the undevolatilized aerogels. Other types of inorganic gelling agents which may be used include a Fumed Silica marketed by B. F. Goodrich Company. It is finely divided and appears very much like an aerogel. It is made by a combustion or vaporization process, as a source of white carbon blac for the rubber industry. The particles are several microns in size and porous in nature.

Another material is Linde Silica Flour marketed by Linde Air Products Co. It is very similar in physical appearance to the silica aerogel. The particle size of the silica is purported to be 0.01 to 0.05 micron and to be manufactured by burning silicon tetrachloride and collecting the combustion product on cool plates analogous to the production of carbon black. The particles are thought to be aggregates or clusters of particles rather than of sponge-like character.

Still another inorganic gelling agent known is Ludox 6 silica from Du Pont which is known as a silica sol, and silica derivatives thereof. 'It has a particle size of the order of 0101 to 0.03 micron.

The silica from Columbia-Southern Chemical Corporation also is useful. These have the following properties:

Wet screen retained 325 mesh, percent .In preparing thickened lubricants it is necessary to remove the water from the sol and replace it with an oil. This is possible by formulating the lubricant and removing the water by flash distillation'orazeotropic distillation.

No attempt is made to enumerate all of the inorganic gelling agents which will be suitable, nor to present examples of all of them since the novel aspects of the invention reside in water-proofing the lubricant rather than the use of novel gelling agents, per se.

The lubricating oil to be used in the process may have any lubricating viscosity. It may be raw oil, acid-refined, or solvent-refined, as required for the particular lubricating need.

Tlre nature of the base oil has been found to make little difierence in the relative consistencies of the thickened lubricants and conventionally (acid) refined oils produce slightly thicker lubricants than solvent refined oils. Excellent working stability is obtained regardless of the type of the base oil. An increase in the viscosity of the base oil, as might be expected, brings increased viscosity to the thickened lubricant and minimizes bleeding. The change is'relatively small and fairly linear. The viscosity of the oil does not atfect the working stability of the lubricant.

The relative proportions of the inorganic gelling agent and the oil will vary somewhat depending upon the desired body in the thickened lubricant, the gelling ability of "the inorganic gelling agent and the viscosity of the oil used. It has been noted, for instance, that with the Linde Silica Flour, the lubricants are somewhat harder, i. e., have a lower penetration than lubricants containing the same weight of Santocel. Lubricants made with low viscosity oils require a somewhat larger amount of the inorganic gelling agent to give a lubricant of the same penetration. The thickened lubricant may vary in consistency from the consistency of a slightly thickened oil to a solid-or semi-solid of grease-like consistency. In general, the amount of the inorganic gelling agent falls within the range of 5 to 20%, and in most cases would fall within the range of 7 to 12% by weight of the thickened lubricant.

The amount of the inorganic gelling agent, as might be expected, aifects the consistency of the thickened lubricant in that an increase in its concentration brings a corresponding increase in consistency. The range is fairly linear and the amount of the gelling agent can be selected with relation to the consistency desired in view of the information in the following examples. While the diiference is slight, the lubricants made with lower concentra tions of gelling agent possess better working stability, while lubricants with larger amount of gelling agent show slightly improved temperature susceptibility characteristics. The bleeding tendencies are decreased by increasing concentrations of the gelling agent.

In general, the properties of the thickened lubricants are remarkably independent of the composition variables and are not critical. The relative concentration of the gelling agent effects the most significant alteration, parmeats ticularly with regard to the final consistency of the product. This permits the manufacture of thickened lubricants having a wide variety of consistencies; p A wide variety of water-insoluble polyalkylene glycol diethers can be employed in accordance with the invention. The molecular weight and chain length of the diether are not critical except as they attect viscosity. Any polyalkylene glycol diethers having a viscosity at 100 F. within the range of 40 to 500 SSU can be employed in the composition of the invention.

The following are a few typical polyaikyiene glycol diethers in accordance with the invention: 1 R-[O-OHr-OH-h-OR:

R[O OH2CH2CH2 1zO 3 n-to-onion-pom 2H5 R[CHzCH2CHaCHz] OR3 R[OCHOH-]z 0 Rs JHa CH3 R[OCHzCHOH2l:OR3

(3H3 R[[O QHrOHqh-[O 011 531115], 0 Rs CH3 R-[[O OH GHaCH2] [OCHz(I3H]b]zORa CH Exemplifying specific diethers within the scope of the invention are the Ucon DLB and DLB-X series of polyalkylene glycols, available from the Union Carbide and Carbon Corporation. These are mixed polyethylene-1,2- propylene glycol dimethyl ethers, of the form of No. 7,

for a few weeks or months it may display excellent water resistance. Preferably, from 4 to 14% imidazoline by weight of the aerogel is used, as such amounts usually impart excellent Water resistance at once. A cheap compound, of course, can be used in much larger quantities than can an expensive compound, at the same total cost for the lubricant.

In some instances, the thickened lubricant may not display a long life when used continuously at high tempera-tures. A breakdown in high temperature stability at high temperatures if it appears is due to a decomposition, through oxidation,and in such circumstances, it is desirable to include an antioxidant in the composition. Conventional amine antioxidants which are more readily oxidized than the components of the lubricant can be employed for this purpose. Tetramethyldiaminodiphenylmethane, available under the trade name Calco MB, is a particularly desirable antioxidant. Only small quantities are required, and ordinarily an amount ranging from 0.1 to about 1% by weight of the thickened lubricant is ample. There is no reason to employ more antioxidant than is necessary to produce the desired effect, but excessive amounts do no harm and amounts up to 5% can be used, if desired.

' The composition is made simply by mixing the inorganic gelling agent, the oil, the polyalkylene glycol diether, the cationic water stabilizer and the antioxidant in any order or manner.

In one embodiment, the polyalkylene glycol diether and, desirably, the cationic water stabilizer and antioxidant, can be incorporated with the inorganic gelling agent either by mixing directly, or if desired, by dissolving them in a volatile hydrocarbon solvent, such as pentane, adding oil, mixing the solution with the inorganic gelling agent,

above, which have the followlng properties: and then evaporatmg the solvent.

TABLE II DLB-144E Standard grade DLB-47-E DLB-67-E DLB-50-B DLB-l-B DLB-265-BX DLB200B Viscosity:

Saybolt seconds at 2. 52 9. 25 10. 76 s 43. 93 57. 22 109 1, 350 2, 465 270 4, 500 10, 300 905 159 157 149 Pour point, F. (A. S. '1. M. 13-97-39) -70 76 72 Flash point, open cup, F. (A. S. T. M. D-92-45). 270 395 485 Do 335 455 555 Density, g./cc. at

The polyalkylene glycol diether should be oil-dispersible.

The polyalkylene glycol diether is incorporated in the thickened lubricant in an amount to impart high temperature stability to the grease. Ordinarily, a concentration of polyalkylene glycol diether ranging from 0.25 to about 2.5% by weight of the thickened lubricant gives satisfactory results. There is no reason to employ more polyalkylene glycol diether than is necessary,.but excessive amounts do no harm, and amounts up -t-oj5% or even higher have been successfully employed.

In general, the concentration of the .imidazoline should at least about 2.5% by weight of the aerogel but Wiii vary depending upon the water stabilizing efiect desired,

the nature of the particular compound selected, the

amount and nature of the gelling agent used, and the economics involved. Both static and dynamic water resistance tend to increase with time, so that anamount of imidazoline may be inadequate to impart the desired water resistance at once, yet after the grease has aged nique can be employed, and, if desired, the mixture can be homogenized in a colloid mill, although this is not necessary.

The mixing temperature is not critical, but is preferably in the range of F. to about 250 F. At higher temperatures grease yield is affected. Mixing temperatures of to F. are preferred.

, Mixing is. continued until the components are thoroughly dispersed in the coil and the consistency has attained the desired level. Any type of mixingis satisfactory. High shear supplemental mixing at a high temoil, gelling agent,-imidazoline and polyalkylene glycol diether. Any of the materials conventionally added to lu- :sion formed. was-noted. Whether theemulsion was an oil-in-water .or waterin-oil type was readily apparent, for the waterbricants and greases can be included. The expression consisting essentially of as used herein isintended to refer to the components which are essential to the composition, namely, the oil, the inorganic gelling agent, the imidazoline, and the polyalkylene glycol diether, and the expression does not exclude other components from the ccmposition which do not render'it'unsuitable for'lubrication, such materials being, for instance, the antioxidant, high polymers to modify viscosity-or viscosity index, materials to impart tackiness, lubricating solids such as graphite, antioxidant additives, corrosion inhibitors of various types, sulfur, additives to render the lubricant snitable'for use in gears, for cutting, grinding, etc.

The following examples illustrate preferred embodiments of the invention. In the examples 'which follow the high temperature stability of the grease was determined by measurement of micropenetrations before and after heating to 400 F. in the block test. The grease was prepared for the determination of high temperature stability by placing approximately 100 cc. of grease in a 150 ml. beaker. The beaker was heated to the test temperature in an aluminum block furnace. This furnace consisted of a solid block of aluminum heated by internal electrical heaters.

Six holes, each large enough to accommodate a 150 cc. beaker, were drilled in the 'top of the block, together with .a thermocouple, so that a measure of the temperature of the block could be obtained. In this manner, six beakers could be heated simultaneously. The beakers containing the grease were placed in the aluminum furnace and heldthere until the equilibrium temperature of the grease reached 400 F. The samples were stirred five-minute intervals during heating. After this the grease was allowed to cool to room temperature overnight and then was stirred vigorously with a spatula. "Micropenetration measurements were obtained on the grease before and after the test procedure. The cycle was repeated as many times as desired and the results are expressed by plotting'the actual penetration against the number of cycles.

The static water stability was determined as follows: A 2 x 2 inch stainless steelgplate was coated with a uniform layer of the grease, following which the coated plate was immersed in a beaker filled with tap water and boiledforthirty minutes.

The dynamic water resistance of the grease was determined as follows: One hundred and fifty grams of grease wasweighed into the ASTM grease Worker cup. The grease then was worked 300 strokes after which a "Shell penetration was obtained. Fifty percent water by I weight of thegrease was added, followed by asecond 300 stroke working cycle. A Shell penetration was again obtained and anobservation made of the type of emul- If free water remained unemulsified this in-oil emulsion was .shinyin appearance while'the oil-in- .good dynamic water resistance if, at'the conclusion of the second 300 stroke working cycle, in the presence of water, the emulsion had not inverted, i. e., the emulsion remained of thewater-in-oil type, whether or not the water added had been completely emulsified. Dy-

namic water resistance was considered excellent if inversionof-the emulsion had not occurred at the end of the third 300 stroke workingcycle, in'thepresenceof water.

l -he' following results are typical of the application of this test to conventional "greases:

Lithium hydroxy- 129 146 '10 TABLE III Shell penetrations tial H20 1120 W/O. Consid erable free water.

stearate.

Aluminum 155 166 Lime 182 Free water. W/O. Barium 141 Do.

Soda... Do. Aerogel (Santocel Emulsion inverted to 0/W ARD).

'W/O means water-imoil emulsion.

2 O/W means oil-in-water emulsion.

These results show that the soap base greases tested were resistant to water, but the areogel grease was not. Accordingly, an aerogel-basegrease that passes the test can be regarded as the-equal of a-soap baseugrease in dynamic water resistance under thesetest conditions, which closely approximate field conditions.

The ability of the grease "t'o'emulsify with free water to some extent is desirable, and therefore in evaluating the test results it is not necessary that the grease emulsify with water, but merely that it not emulsify with water to the point where inversion to an oil-in-water emulsion occurs.

The working or mechanical stability ofthe greases was evaluated by 10,000 strokes working at room temper- ,ature in the ASTM grease worker and by four hours at room temperature in a grease working assembly wherein the greases'ample was subjected to the severe working afforded by close intermeshing gears in an enclosed space. This approximates many field conditions for general ball and roller bearing and transmission greases. The measurements include a Sohio'micropenetr-ation of the grease before working, a Sohio micropenetration after working, plus a Sohio micropenetration after the grease has been allowed to stand for approximately twenty-four hours, and another after the set up in grease body has been disturbed by vigorous stirring with a spatula. The last two measurementsofEer further data on the ability of the greases to resist mechanical breakdown.

Exa'mples'l io 10 Percent Santocel ARD 9.0. Ucon lubricant 2.0. Amine 0" Amount indicated in table below. Paratac 2 a 1.0. Paraflow 3 0.5. Ortholeum 0.5. Solvent extracted bright-stock (2000 S SU at 100 F.) 5 89.2.

1 1-,B-hydroxyethyl-2-heptadecenyl-imidazoline.

An isobutylene polymer sold by the Enjay Company, Inc. and commonly used in compoundinggreases.

A Friedel-Crafts reaction product, useful as a pour point depressant and sold by the Enjay Company, Inc.

' An antioxidant for mineral lubricating oils. i

46.5 volume percent solvent-extracted bright stock, 78 SSU at 210 F. and 53.5 volume percent solvent-extracted bright stock, 250 ssu at 210w.

The oil solu'ble additives, i. e., the Paratac, Paraflow and Ortholeum 300, were dissolved in the oil. The oil was brought to 95 F., the. Amine '0 and Ucon added with thorough mixing and then the'Santocel was blended in as rapidly as it was absorbed in the mixture. The total mixing time was sixty minutes at the temperature indicated in the table.

- TABLE IV Temp., F. Final ASTM penetration Example Percent Ucon polygrease Initial 24 hr. No. Amine mer temp., Shell Shell 1 Initial Final 1 pen. 0 60 oil bath oil blend strokes strokes 0 DLB 190-B 100 99 100 155 165 325 325 4 DLB 190-B 95 95 93 157 170 332 326 8 DLB 190-B 97 98 95 162 179 337 339 12 DLB 190-B 97 95 96 157 190 341 349 14 DLB 190-13 95 95 94 185 195i 352 '352 8 DLB 50-B 96 96 95 152 168 322 318 8 DLB l44-E 96 95 109 168 182 337 334 DLB 100 95 102 105 118 283 295 1 Based on weight of Santocel ARD.

The table shows that in many cases the grease yield decreases as the amount of Amine 0 increases and this is a linear decrease as is evident when the results are plotted on a graph. It would be concluded from this data that the smallest amount of Amine 0 required to give the desired Water resistance should be employed.

The dynamic water resistance of these greases was TABLE VI evaluated by the tests described above and are summarized test bel w; Example No.

TABLE 2m) m) 400 Dynamic water resistance 241 258 265 E. 2 22. 22.

cell 2 5 No. Amine Shell pens. 285+ 285+ 285+ 0" 1 Comments 285+ 285+ 285+ 285+ 285+ 285+ orig. 100% 285+ 235+ 285+ 285+ 285+ 285+ 285+ 285+ 285+ 1 0 Oil-m-water emuls1on-invers10n:c0m- 285+ 285+ 285+ plete breakdown of grease. 272 285+ 285+ 2 4 Nearly inverted-free unemuLHaO. 253 285+ 285+ 3 8 162 146 70% Water-in-oil emulsion% tree 235+ 285+ 285+ unemul. H2O. 285+ 285+ 285+ 4..-" 12 157 149 50% Water-in-oil emulsion-50% free 5 14 185 197 a i it? 11 111 707 n 0 a crime em sion 'ee uiiemul. 1120 0 The working stability of Examples 1 to 7 was deter- 8 152 146 ZfiQLfiRQ? emulsln 25% free mined by the four hour test in the gear grease worker. 7.- 8 168 144 80% Waltlzer-in-oil emulsion-20% free The results obtained appear in the following table:

11119111 2 8"--- 10 136 122 Water-in-oil emulsiorr-free unemul.

1120. TABLE VII 113 1 rats 1: lARD.

on E g t 0 an ace Sohio micropenetration Gain in It is evident that 8% Amine O by weight of the E 1 N penetration Santocel was sufiicient to impart good water resistance. mmpe The results for Examples 3, 4, 5, 6, 7 and 8 are to be Original \Zl d. At rest 2: 1ers lfl 'd. 2x 4 1 12 contrasted with Example 1 which did not contain Amine s e s e 0 but did contain 2% of the Ucon lubricant. This j 115 157 119 170 42 .55 shows that the Ucon lubricant alone, even at a concen- 101 110 100 12g 9 27 i 122 152 125 201 30 79 tration of 2%, is not able to impart the necessary dynam c 132 156 1 15 191 24 59 water reslsta nce- 115 196 147 217 79 102 As an additional comparison two greases were prepared E2 122 +32 $3 a containing 5 and 15% Amine 0, respectively, by weight of the Santocel, and no Ucon oil. These greases had the following composition:

Example 9 Example 10 Percent Percent Ortholeum 300 0.5 0.5 Solvent extracted bright stock (78 SSU at 21 The changes of penetration shown in the table are of an order of magnitude indicating satisfactory mechanical stability.

These results show that greases containing Amine 0 alone even in amounts as high as 15% by weight of the Santocel or a Ucon lubricant alone have either satisfactory dynamic water resistance or satisfactory high temperature stability, but not both. On the other hand, greases containing both the Amine O and the Ucon oil have excellent static and dynamic water resistance as well as good high temperature susceptibility properties even though the amount of Amine O is as low as 8% by weight of the Santocel and the Ucon oilis in the same amount as when used alone. Evidently in the presence of the Ucon oil the Amine O is more effective in smaller amounts to impart dynamic water resistance while not affecting high temperature stability. The same effect is not obtained when diethylene glycohmonoethyl t v 13 V alkylene glycol diether's-j of .higher molecular weight. [This is shown bythe following: i I v V greases we're prepared .having the. following formulation: 1

useless.

The results showthat with Carbitol at least 10% Very goo 1 Based on weight Santocel ARD.

- Amine O is necessary for satisfactory performance in Example? 11 t 6 the static boiling water and that at least 14% is necesi Pe n sary in the dynamic water test. This shows that Santocel ARD 9.0 Carbitol, diethylene glycol monoethyl ether having two i v (diethylfilna glycol n ethylene glycol units. is not as effective as'the higher ethyl ether) 2L0 in polyalkylene glycol diethers such as the Ucons, which are Amine O A o nt indicated polymers of ethylene'and 1,2-propylene glycol units, in f A ia belOW- cooperating with the Amino "O to give good dynamic P ratac 1- water resistance. q j Paraflow 0.5 The thickened lubricants of the invention are useful in Orthbleum c300 0-5 is many field grease applications. In the cn'tcial field of l lubricating (2000 SSU wheel bearing lubricants, these greases have performed at 100 F.) 85. 92 very satisfactorily. Other successful field-applications in- '465 volume percent solvent-extracted bright stock (78 elude chassis lubrication, general ball and roller heal" 5 %y% Percent Solvent-extracted bright ing applications, foundry ladle trunnion bearings, phonograph bearings, textile spinning wheels, cam followers, 'P a z Paraflow and orthokum V300 i' f kiln car bearings, farm equipment, worm gear-radar and m h s'imt'ocelt Amme and tennae, outdoor playground equipment, shaker screens tol then 'were blended and the preparation mixed at and gears and mixing vessels. 0 f sixty minutes Overall: including the time The greases of the invention are characterized by their necessary to a f Samocelease and reproducibility of preparation and their high Shell penetratlon? were taken 9 all of the grease static and dynamic water resistance and high tempera- P S coljlcluslm P the InlXlIlg cycle Second ture consistency stability. In addition they have excel- Shell Penetration Obtamed after the grease had Stood lent oxidation resistance and mechanical stability. All of ovelmght- The Standard ASTM 0 and 60 stroke P 7 these are requisites for amultipurpose lubricating grease, trations also were taken after the grease had stood over- Testing the high'temperamre Stability f the thickened mght- The results are glven in followmg table: lubricants of the invention by heating the greases to 400 T B 'VIII F is an extreme test inasmuch as the highest temperature to which a grease is subjected under even extraordi- Initial 241m 241m ASTM nary conditions of use is about 300 F., but the. temper- Example, A m 1 Shell Shell Penetrations ature was adopted as a suitable test standard because a 'pm. ii ii ii ii grease stable at 400 F. definitely will have thestability Ostrokes 60 str necessary to withstand heating'to 300 F. It will be understood that for normal purposes the thickened lubri- Percmtfi 123 120 269 274 cants of the invention need not be stable at temperatures 3 137 136 285 290 above about 300 F. and that the greases of the invention lg at least meet this requirement. Where the term high 14 184 190 334 344 temperature stability is used, it will be understood to 16 8 400 416 I mean that the thickened lubricant is stable against loss of consistency at temperatures of at least 300 F. Based 011 the Weight SantoceL The Shell penetrations are in accordance with the Shell The greases were tested for high temperature stability, Microcone Penetration Test, Institute Spokesman and showed satisfactory high temperature stability char- (NLGI), volume VI, Number 12, page 1 (1943). acteristics after five cycles. Furthermore, those greases The Sohio micropenetration technique employed recontaining the higher amounts of Amine O which had quired a microcone and cup. The microcone was specialgiven low grease yields stiffened with the heating during 1y built, and its dimensions are compared in Table II with the test, compensating for the low yield therein. those of the standard ASTM cone, ASTM Designation The water resistance characteristics of the greases were 217-48, described on page 143 of the November, 1948 checked by a static Water test and the dynamic Water edition of D-2 Specifications for Petroleum Products.- test in the ASTM worker. The results are shown in the The cone and grease cup employed in obtaining the test following table: results required a minimum sample size of 35 ml.

TABLE IX Dynamic water resistance Percent Exglnple igi n e Static 30-minute boiling water test Shell pens.

. I Results Orig. H20

6 Very poorconsiderable emulsion-doses grease characteristics. 8 Poor-considerable emulsion-loses grease-like characteristics. 10 vGood 12 d Oil-in-water emulsion-inverted. 14 do Water-in-oil free HzO-still adhesive. 16 280 108 Water-in-oil emulsion small amount free HzQ-still adhesive.

TABLE X MIOROCONE DIMENSIONS ASTM SOHIO Cone Cup Gone Cup Diameter, mm- 65 78 20 43 Height, mm. l7 Depth, mm- 65 24. Surface, sq. m 4, 778 620 1, 470 Volume, cc 290 35. (3 Gone diam./cup surface 0.136 O. 136 Gone height/cup depth. 0. 693 Weight of assembly. gnis- 150 1 13 Weight of assembly/sq. mm. cone surface 0. 021 0. 021

1 Calculated.

All parts and percentages are by weight of the thickened lubricant unless otherwise indicated.

I claim:

l. A thickened lubricant of high temperature stability and good dynamic water resistance, consisting essentially of a mineral lubricating oil of lubricating viscosity as the major component, a finely-divided inorganic watersusceptible oil thickener in an amount sufficient to impart a grease consistency to the oil, a water-insoluble oilmiscible polyalkylene glycol diether having a viscosity at 100 F. within the range of from 40 to 500 SSU, and a Water-insoluble oil-dispersible cationic surface-active imidazoline having an aliphatic group substituted at the 2-position and a hydrophilic group substituted at the 1- position of the imidazoline, said glycol diether being in an amount within the range from 0.25 to about 2.5% by Weight of the thickened lubricant, and said irnidazoline being in an amount Within the range from 4 to 14% by weight of the inorganic Water-susceptible oil thickener, each being in amounts suflicient in combination to impart high temperature stability and dynamic Water resistance to the thickened lubricant.

2. A thickened lubricant in accordance with claim 1 in which the polyalkylene glycol diether is a mixed po1yethylene-1,2-propylene glycol diether.

3. A thickened lubricant in accordance with claim 1 in which the imidazoline is I-B-hydroxyethyl-Z-heptadecenyl imidazoline.

4. A thickened lubricant in accordance with claim 1 in which the inorganic oil thickener is a silica aerogel.

5. A thickened lubricant of high temperature stability and good dynamic water resistance, consisting essentially of a mineral lubricating oil of lubricating viscosity as the major component, a finely-divided silica aerogel in an amount suflicient to impart a grease consistency to the oil, a water-insoluble oil-miscible mixed polyethylene- 1,2-propylene glycol diether having a viscosity at 100 F. Within the range of from 40 to 500 SSU, and a'water-insoluble oil-dispersible cationic surface-active imidazoline having an aliphatic group substituted at the 2-position and a hydrophilic group substituted at the 1-position of the imidazoline, said glycol diether being in an amount within the range from 0.25 to about 2.5% by weight of the thickened lubricant, and said imidazoline being in an amount within the range from 4 to 14% by weight of the inorganic water-susceptible oil thickener, each being in amounts sufiicient in combination to impart high temperature stability and dynamic water resistance to the thickened lubricant.

6. A thickened lubricant in accordance with claim 5, in which the imidazoline is I-B-hydroxyethyl-Z-heptadecenyl itnidazoline. 7

References Cited in the file of this patent UNITED STATES PATENTS 2,554,222 Stross May 22, 1951 2,573,650 Peterson Oct. 30, 1951 2,652,365 Moore et al. Sept. 15, 1953 2,655,476 Hughes et al Oct. 13, 1953 2,711,393 Hughes et a1. June 21, 1955

Claims

1. A THICKENED LUBRICANT OF HIGH TEMPERATURE STABILITY AND GOOD DYNAMIC WATER RESISTANCE, CONSISTING ESSENTIALLY OF A MINERAL LUBRICATING OIL OF LUBRICATING VISCOSITY AS THE MAJOR COMPONENT, A FINELY-DIVIDED INORGANIC WATERSUSCEPTIBLE OIL THICKNER IN AN AMOUNT SUFFICIENT TO IMPART A GREASE CONSISTENCY OF THR OIL, A WATER-INSOLUBLE OILMISCIBLE POLYALKYLENE GLYCOL DIETHER HAVING A VISCOSITY AT 100*F., WITHIN THE RANGE OF FROM 40 TO 500 SSU, AND A WATER-INSOLUBLE OIL-DISPERSIBLE CATIONIC SURFACE-ACTIVE IMIDAZOLINE HAVING AN ALIPHATIC GROUP SUBSTITUTED AT THE 2-POSITION AND A HYDROPHILIC GROUP SUBSTITUTED AT THE 1POSITION IN THE IMIDAZOLINE, SAID GLYCOL DIETHER BEING IN AN AMOUNT WITHIN THE RANGE FROM 0.25 TO ABOUT 2.5% BY WEIGHT OF THE THICKNED LUBRICANT, AND SAID IMIDIAZOLINE BEING IN AN AMOUNT WITHIN THE RANGE FROM 4 TO 14% BY WEIGHT OF THE INORGANIC WATER-SUSCEPTABLE OIL THICKENER EACH BEING IN AMOUNTS SUFFICIENT IN COMBINATION IN IMPART HIGH TEMPERATURE STABILITY AND DYNAMIC WATER RESISTANCE TO THE THICKENED LUBRICANT.