US2491641A - Production of an aluminum base grease containing organic amines - Google Patents

Description

Dec. 2U, 194-9 BOND} 2,491,641

PRODUCTION OF AN ALUMINUM BASE GREASE CONTAINING ORGANIC AMINES Filed June 27, 1946 3 Sheets-Sheet l M A. r

ATTORNEY Dec. 26, 1949 A. A. BOND! PRODUCTION OF AN ALUMINUM BASE GREASE CONTAINING ORGANIC AMINES 5 Sheets-Sheet 2 Filed June 27, 1946 Dec. 26, 19 49 A. A. BOND] 2,491,541

' PRODUCTION OF AN ALUMINUM BASE GREASE CONTAINING ORGANIC AMINES Filed June 27, 1946 3 Sheets-Sheet 3 fig: 11

INVENTOR, M A M/ BY g (M Patented Dec. 20, 1949 PRODUCTION OF AN ALUMINUM BASE GREASE SONTAINING ORGANICVAMINES Arnold A. Bondi, New Orleans, La., assignor, by mesne assignments, to She'llDevelopment Com pany, San Francisco, Califi, agcorporation f- UNITED S'l Delaware Application June 27, 1946, Serial No. 679,727

9 Claims;

aliphatic amine which functionsunder the conconsistency and which wasnon-bleeding, a cerditions under which the grease is cooled to pro.- tain fraction ofthe' total aluminum soap content duce a smooth homogeneous grease gel which is comprises. the di salt of 12-hydroxy stearic acid non-bleeding. or 12-'-hydroxy stearate. This is quite an expen- In accordance with the present invention, a sive ingredient and may bedispensed'with emnon-bleeding and non-graining aluminum base 10 ploying the present'invention, and yet there will grease, that is a grease with a buttery texture is be produced a smooth non-bleeding grease. Howproduced by incorporating in the aluminum base ever, in carrying out the invention, the total soap grease from about .05 to about 3% of an aliphatic content may comprise a small amount of the 12- amine and feeding the grease in a fluid condition hydroxy stearic acid. in a relatively thin layer on to a heat conducting 15 It is also desired to point out that in the presurface which passes through a single or pluferred form of the invention the mineral oil used rality of cooling zones, the grease while being in producing'the grease has a low to medium moved being maintained in a quiescent state and Viscosity ge, O example 100 o 2990 S- -a being subject to the continued action of a cooling andwhen a mineral oil' having such a viscosity medium, as for example: air, said grease being is used in making reases Conta n an alucooled in a single continuous operation to preferminum soap the' fatty acids of the character ably below the transition point of the grease in herein setforth or ofanyof' the acids as herein a time period of less than one hour and usually Set forth, d' y s being preferably th s in a time period varying from three minutes to 0 taining 14 17024 carbon atoms'in a molecule, fifteen or twenty minutes, there being produced 26 it is exceedingly difficult to obtain a non-gra y a smooth homogeneous grease gel. grease chilling from the fluid state to a solid It is desired to point out that this method of O1 semi-Solid state inlessthan one hour. cooling contrasts with the prior art method of n cordancc With'the present invention, ancooling an al i ba r aid prior art. aliphatic amine is incorporated in greases made method comprising cooling the greases in rela- 30 with theselow to medium viscosity range oils, and tively thick'layers in a pan or cooling the grease e as y be Chilled 0 a nee in a helical screw conveyor where the grease is sm o h coherent gel in much less time than one subjected to a. shearing stress. hour, as for'example in from 3 minutes to 40 In accordance with the present invention, the minutes, and usual y 3 minutes to 20 minutes aluminum base grease containing an aliphatic 35 When processed in accordance with the present amine as an inhibitor of crystallization is fed to disclosure. a steel belt or the like so as to form arelatively While the primary Object of the present iIlVBIP' thin continuous layer on the steel belt, and is n" is o p e a uminum soap grease inthere subjected to a current of air or other coolacCOrdance With the p edure above outlined ing medium so that the grease while being Carried 0 and to produce ea avi e advan a es along with the belt is cooled in a uniform fashion above $613 O some of the most important obfree from shearing stress. J W l beset fO h- In accordance with the present invention, there B715 9 Of'the' objects of the present invention is provided an aluminum soap grease which has to provlde a method 9 cqoling'an aluminum Soap the desired consistency, and this is obtained using greas? such as lubncaitmg grease cqmiaining less aluminum soap than has been customary in t m Soap hlgher fatty acids the prior art. Previously, to obtain the desired Tammany t p steal-ate. soap comprlstng consistency, it was necessary to use 6.5% to 7.5% mcqrpomtmg m the grease pnor to. the coolmg f 1 te r t Q 1 t of the grease and while the: grease is in a fluid Q um a e 01 an eq 1va en Ian y state, an aliphatic amine, and feeding the grease acld to obtam grease havmg Worked to a-heat conductivesurface in an amount to form, pepetratwn of to 9- P Pontrast theretfi, a thin layer on said conductive surface, and exusing the present invention, it is only necessary osing the grease; in the absence of shearing to use /2% 0 6% of the aluminum stearate o stress, that is While the grease is in a quiescent an-equivalent amount of an aluminum soap of any 55 state to the action of a cooling medium which is of the higher fatty acids or other acids herein set forth. While the present invention has the ad-' vantages set forth, higher amounts than 5 2 or'6% may be 'used if desired, but are not usuallynecessary.

Further, it is desired to point out that in order to produce an aluminum soap grease of the proper" preferably directed countercurrently to the travel of the grease on the moving hot conductive surface.

The aliphatic amine may be a saturated aliphatic amine, and includes the saturated primary, secondary and tertiary amines and the cyclo-aliphatic amines, all of said amines containing more than carbon atoms and less than 36 carbon atoms per molecule, but preferably containing to 18 carbon atoms per molecule. Instead of using the amines above set forth, their fatty acid soaps may be used, the soaps of said amines containing more than 5 carbon atoms and less than 36 carbon atoms per molecule, and preferably 10 to 18 carbon atoms per molecule, the carbon atoms of the acid radical of the soap, such as the fatty acid. radical, being included as part of the carbon atoms of the molecule.

A second object of the present invention is to flow a compounded grease containing an amine crystallization inhibitor of the character set forth in a hot fluid condition on to a relatively thin conductive surface, as for example a thin metal band, so as to form a thin layer of grease Varying from approximately 0.1 to 1" in thickness on the band, and to thereafter move the metal band and the grease through a cooling zone to form a highly transparent grease.

A third object of the present invention is to provide a method of continuously cooling an aluminum soap lubricating grease in thin layers of the character herein set forth, and while in a quiescent state, the rate of cooling of the grease being varied as the grease cools from its hot fluid state.

A fourth object of the present invention is to quickly cool an aluminum soap grease, of the character herein set forth while in thin layers in successive cooling zones, one cooling zone being adjacent the hot end of the cooling belt, and the other cooling zone being adjacent the discharge end of the cooling belt, said zones being.

for convenience designated respectively hot and cold cooling zones, there passing through the zones a cooling medium, and there being a differential between the velocity of the cooling medium in the two successive cooling zones. The ratio of the velocity of the cooling medium in the cold zone to the velocity of the cooling medium in the heated zone varies over the range of 1:1 to 10:1.

A fifth object of the present invention is to provide a smooth non-b1eeding transparent alumi-- num base grease of buttery consistency, said grease containing less than 5 /2% to 6% of aluminum soap of the higher fatty acids, and 115% to .3% of a saturated aliphatic amine or cycloaliphatic amine or amine fatty acid soaps, said amines being of the character hereinbefore set forth.

It is a sixth object of the present invention to produce an aluminum soap lubricating grease having an aliphatic amine of the character set forth by cooling the grease in layers of .1" to 1" in thickness while the grease is being subjected to a rapid current of cold air while it is cooling in a single operation from about 350 F. to about 80 to 90 F. within a time period varying from about 3 minutes to 40 minutes while the moving grease is subjected to a countercurrent flow of a cooling medium, said grease being maintained in a quiescent condition and being free from shearing stresses during the cooling period.

The present invention will be described in connection with the accompanying drawing in which:

Figure 1 is a plan view of a grease cooling apparatus in accordance with the present invention;

Fig. 2 is a detail of the end of the belt showing the cooling means and baffling means taken substantially on the line 2-2 of Fig. 1;

Fig. 3 is a section taken on the line 33 of Fig. 2, illustrating the grease feeding means;

Fig. 4 is a detail of the supporting means for the upper portion of the belt;

Fig. 5 is a section taken substantially along the line 55 of Fig. 1;

Fig. 6 is a side elevation of the grease cooling apparatus of the present invention;

Fig. 7 is a section taken substantially along the line 'l'! of Fig. 6;

Fig. 8 is an enlarged detail of the means for removing the grease from the belt;

Fig. 9 is a side elevation of a modified form of the grease cooling apparatus; and

Fig. 10 is a plan view thereof.

Fig. 11 is an enlarged side elevation of a portion of the casing partly broken away to show the diverting baffles.

Referring to the figures of the drawing, and particularly Fig. 1 thereof, a grease cooling apparatus in which the present invention may be carried out is indicated in general at H]. The apparatus includes a sheet metal casing which is generally rectangular in cross section, as best shown in Fig. "1, including a top H and a pair of sides 12 and It. The casing is supported as by longitudinal I-beains it, carried on transverse beams l5 which are in turn supported in any conventional fashion on the columns [6. The casing is preferably constructed of sheet metal or may be constructed of any suitable thin material of sufficient structural strength.

Trained over suitable pulleys l1 and I8 is a steel belt I9, provided with apair of strips preferably of a synthetic rubber, indicated at 29 and 2| respectively. These strips which extend entirely around the belt adjacent the edges thereof, prevent the hot grease from flowing off the edges of the belt. They are preferably bolted to the belt by suitable bolts not shown, although they may .be riveted or otherwise suitably fixed to the belt. The right hand pulley ['8 is driven by means of a suitable belt 22 from a variable speed transmission and motor indicated in general at 23 (Fig. 1). The belt is kept under tension by a suitable tension means consisting of a tensioning frame 24 urged by means of a weight 25 connected to the tensioning frame as by cables 26 and turned over suitable pulleys 21. Preferably, the weight 25 is sufficient to urge the frame 24 and journals '28 for the pulley 11 with sufficient force so that the steel belt is kept constantly under tension, and tends to assume a horizontal position. The upper course of the belt is preferably supported on a plurality of U-shaped steel rods, best shown in Fig. 4, and indicated by the reference numeral 29. A plurality of steel rods 29 are distributed across the width of the belt in any suitable manner. The lower ends of the steel rods are passed through supporting frame members 30, and are provided with a threaded section carrying nuts 3! and 32. This permits either end of the rods to be raised or lowered, so that the belt may be supported thereon in an absolutely horizontal position. Further, the use of these rods does not present any substantial air resistance to the flow of cooling air which is passing along the lower surface of the steel belt I9. The cooling air is fed into the outlet end of the casing about the belt from a pair of blowers 33 and 34, the blower Abafil is providedwithi'n the casing, indi cat'ediat so that'th'e' air flow. from the upper blower 3'3 isinsubstantial" parallelism with the upper surface 'of'the belt 1'9? A plurality of dischargesare providedfro'm the lower blower, one= discharge being on 'each side ofthe' casing; and

indicated ates 'and"3T'respectively. It will be noted that these discharges also feed in substantially parallel tothe lower surface of the belt, and at the outlet'endof the casing. The

airis exhausted from the casing asby'a stack '38 directly "communicating. with the upper or top of the inlet'endof the-casing; andprovided with a pair ofrlucts 39and 39c communicating with the casing below the upper course of the belt, as'best shownin Figs. 1 and 6. The lower course of the belt is supported in conventional fashion on idler pulleys 49. The lower course of the belt lSa may also be supported in any suitable manner, but preferably by steel rods as described above and as shown for support of'the upper course of the belt IS in Fig. 4. This lower course [9a of the belt may be encased andprovided with means of supplying cooling. medium through the casing. In this manner, the lower course [9a may be used for-the cooling of the grease, whereby the capacity. of a given installation may be approximately doubled.

Grease is fedinto the apparatus and distributed uniformly over the surface of the belt as by an inlet conduits l, feeding into a header 42, provided with a plurality oi-distributing. outlets 43. Positioned between the outlets 43' and the exhaust stack 38 is an adjustablebafil'e 4-4 which prevents too rapid cooling of the grease immediately after being fed, and permits the grease in hot liquid condition to spread out on the surface of the belt in a uniform; layer. A dam in the form of an angle and indicated at 45 is provided to prevent the grease-from flowing. on the end of the belt. Preferably the dam or angle iron 65 is provided with oil resistant synthetic rubber ends or surfaces where it is in contact with the grease and there is thus provided prior to the exhaust stack of the device a relatively warm zone which is free from the cooling medium, i. e. as otherwise the cold air striking the grease is'likely to cause chillin'gand non-uniformity in layer structure upon being fed.

The outlets 43 in general should be more than six inches and less than eighteen inches apart, preferably from eight to fourteen inches apart, since ifthey are too close too much grease will be fed, and if they are too far apart non-uniform distribution of grease will be produced. In order to insure uniform fiow of the hot fluid grease from all of the outlets, the combined cross sectional area of the outlets 43 should be smaller by about 25 to than the cross sectional area of the header 62.

The belt as shown in Fig. 6 is rotated in a clockwise direction, and the cooled grease is removed from the belt as by a scraper 46, best shown in Fig. 8. A funnel 41 is positioned to catch the grease being removed from the belt and distribute the same into either one of a pair of tanks 48 and 49 respectively, as shown in Fig. 5. The funnel 41 is provided with a pair of ports at each of its sides, closed bysliding covers 59 and 5|. When the cover 5| is in the'position shown in Fig. 5, grease will be fed into the tanl' '*48"r When the 6%? cover" 5l"is slid downwardly to close theopening-y andthecoverfifl is-slidupwardly to open the-port, greasewillbe rec-into the-tank--49. The tanks ill and i9 are provided with conical bottoms; and feed through-a 'valve 52 and a positive displace-* ment pump 53 into a*-'suitable--grease strainer 54: In" the form of'theapparatus: shownin=-Figss 9 and 10, an intermediate pair- 0f 'exhaust 'ducts '5 and- 550; are provided at anoint-56 located-ap proximately" one-third of the distance between the hot endofthecas-ing-and the cold end of the casing, the point 56 being closer to the hot-end of"thecasing: The-point 56 definitely mar-ks the dividing line between-the so-called hot'zone A 1 and the so-called cold 'zone'B-. Also-within the main casing--51"whichcorresponds to the casing lilshownin Figs. 1--to 6 inclusive, there are pro-- vided adjustable bafiles" 58 and tea which serveto regulate the rel'ativeamountof air flowing through the discharge"ducts-55" and- 55a -respec-- tively"and-the balance-of-the main casingr The intermediate exhaust duets may be connected -to the-exhaust ducts 39' or communicate directlywith the' stack 38.

Utilizing the'form of'apparatus shown inl igsn9 and-10;a portionofthe'cooling area orother cool ing gaseous'me'dium'maybe exhausted; that is let out'at an intermediatepoint ofthe'casing 51',- the amount of air which is let out beingregulated bymeans ofthe bafiles 58"and"5&ato=thereby perform the first" stage of cooling atwhighertem perature'level', thatis at a'lower rate ofcoolingas is desirable with some greases-in order-to-im-- prove't'heir quality? mother words,--the*time of cooling is divided up'intotwoperiods;a first period and a second" period: The rate of'co'oling when the grease ishot; that is during'the first period, is lower than the rateofcooling during the second period when" the" grease has already cooledsomewhat and started to gel. B'y exhausting the cooling medium intermediatethehot and cold ends'pf' the" cooling grease layer; thereis maintained a control overthe-velocity of fiow'of the cooling: medium in the casing whilethe cooling medium is in contact with the moving layer of the grease. The distance through which the grease'spread in a thin layer travels from the hot end of'the grease layer to the'cold endof the grease layer is divided, as stated, into what may be termed a hot zone A and" a relative cool zone B, and the grease is then cooled in these zones or stages, namely a first? stage and. a second stage. In the first stage at and adjacent the hot end of the grease layer the velocity of the cooling medium is preferably lower than the velocity of the cooling medium in the second cooling stage at and adjacent the cool discharge end of the grease layer. The ratio of the velocity of the cooling medium in zone B, that is, the second stage, to the velocity of fiow of the cooling medium in the hot zone A, that is the first stage, may vary over the range of 1:1 to 10:1. In other words, the rate of cooling in zone A islower than the rate of cooling in the second cooling stage in zone B'. More specifically, the rate of cooling of the aluminum soap-lubricatinggrease from its hot fluid state which may be as high as 350 F. down to about 175 F. is slower than the rate of cooling in the second cooling stage in zone B where the grease preferably cools to below its transition temperature, that is usually below 100 F. or F.

Thecooling medium may be conditioned by adjusting its temperature and/or velocity and by other physical or chemical characteristics to cool "the grease at a slower rate of cooling in zone A than in zone 13. While in one form of the invention it is desirable to employ two-stage cooling, it is within the province of the present invention to dispense with the two-stage cooling and uniformly cool the grease as it passes from the inlet end of the cooling belt to the outlet end thereof.

Preferably the grease is fed to the belt at such a speed so that a layer of grease of the proper thickness is produced. If the layer on the belt is more than approximately one inch thick, the rate of cooling will be prohibitively low, and in the case of certain greases the grease will tend to flow in an uncontrollable manner along the belt, due to the slow rate of gelation. If the layer is less than 0.1, the rate of heat transfer through the grease is more rapid than the rate of heat removal from the grease by the air stream within the practicable range of air pressures, and air velocities. Preferably, the grease is cooled by air at room temperature, but the air used for cooling purposes may be passed through a suitable refrigeration plant and supplied to the cooling duct at a temperature as low as F. On the other hand, where warm outside temperatures prevail, the cooling air may be supplied at temperatures as high as 100 F. In other words, in general the cooling air at atmospheric or higher pressures may be supplied at temperatures of 0 to 100 F. Preferably however, the grease should be cooled to approximately 80 to 90 F., and therefore the cool air should be supplied at a temperature lower than 80 to 90 F. and preferably between 40 F. and 90 F. Since the grease moves in a thin layer on the belt, the various particles of grease are not displaced relative to one another, and there is no shearing stress set up.

In general, the belt is preferably approximately 100 feet long, and moves at a speed of 13 feet per minute, so that the total time of cooling for the average grease is approximately 7 to minutes. This is sufficient to cool the grease and set the same at least to a jelled mass. The blowers 33 and 34 may be a standard type of blower capable of blowing approximately 30,000 cu. it. a minute, and the tanks 48 and 39 are capable of holding one charge of the belt. In the case of a belt approximately 6 ft. wide and 100 ft. long, this would amount to approximately 15,000 pounds. By providing two tanks of this type, the grease may be allowed to remain in a quiescent condition after cooling.

The following is an example of an aluminum soap grease made in accordance with the present invention:

Example I The grease may be compounded as follows:

Aluminum di-stearate -55 lbs. (5.5%) Coastal pale oil of 100 vis.

at 100 F 110 lbs. Coastal pale oil 2000 vis.

at 100 F. -830 lbs. Polyisobutylene solution .3 lb. (3%) Stearylamine .5 lb. (.05%)

The aluminum di-stearate and the coastal pale oil of 100 viscosity at 100 F. are thoroughly mixed at room temperature, and then heated under continued agitation to about 350 F. Then the 2000 viscosity coastal pale oil is added as well as the polyisobutylene solution and the monostearylamine. During the addition of these ingredients, the temperature is preferably held at around 325 to 355 F. After complete homogeneity has been obtained, the hot grease in its fluid condition is pumped on to the moving belt H! of the cooling apparatus at such a rate that a depth of grease layer of about one-third of an inch is produced. Cooling air is supplied to the tunnel or casing by the blowers 33 and 34 at a velocity of 3500 feet per minute, and at a temperature of approximately F. The belt is moved at a speed of approximately 10 feet per minute so that the grease remains on the belt for approximately 10 minutes, and then is discharged into one of the tanks 36 or A9. The temperature of the grease upon discharge is about F. The aluminum soap grease is moved as a quiescent mass countercurrent to the air stream.

The resulting grease is of smooth texture, transparent, non-bleeding and slightly tacky. The ASTM worked penetration after 60 strokes is 325 decimillimeters, and after 300 strokes 348 decimillimeters.

It is to be noted that the grease cooled in accordance with the above required about 10 minutes to cool, and did not require any interruption for the transformation of the rubbery stringy grease mass into a smooth transparent coherent gel at the 120 F. temperature level as is required by the prior art.

Referring to the above example, it is noted that the amount of aluminum stearate grease used is 5 Proceeding in accordance with the prior art, it would have required about 6 /2 of aluminum distearate plus 0.6% of aluminum di-12-hydroxystearate in order to obtain a grease of like consistency. and the grease would have to be processed in an entirely different manner. As pointed out, the aluminum di-12-hydroxy stearate is a rather expensive ingredient, and its use is eliminated by the present invention.

Example II An aluminum stearate grease may be compounded as follows:

Aluminum stearate 11 lbs. (5.5%) Paraffin oil,

vis. at 100 F "a 50 lbs. Red oil,

2000 vis. at 100 F. -l39 lbs. Polyisobutylene solution (7% con.) /2 lb. (25%) Dicyclohexylamine 2 oz. (0.06%)

Example III Instead of using dicyclohexylamine, as set forth in Example II, there may be substituted therefor hexadecylamine in amounts varying from 0.05% to 0.25%.

In the above examples, there may be added between 0.05% and 0.25%, and preferably between 0.10% and 0.15% of gum rosin or abietic acid to increase the hardness of the grease. The aluminum stearate added to the grease may be the mono-, di-, or tri-stearate, or a mixture of any of these salts.

In carrying out the present invention, .saponifiable organic constituents of the grease-making batch may be any of the saponifiable organic constituents generally used in the production of a lubricating grease, said organic constituents being combined with aluminum to produce an aluminum soap. The fatty acids usually used in grease making are in general the saturated fatty acids containing up to 32 carbon atoms, and usually from 14 to 24 carbon atoms; and the unsaturated acids containing up to 32 carbon atoms and usually from 18 to 22 carbon atoms. The fatty acid which is used to make the aluminum salt may be a saturated fatty acid or an unsaturated fatty acid, and includes stearic acid to produce aluminum stearate, 12-hydroxy stearic acid, 9, IO-hydroxy stearic acid (that is the 9 and 10 carbon atoms carry the two hydroxy groups), 4-hydroxy palmitic acid, iso-stea-ric acid, iso-palmitic acid, l2-hydroxy, 9-o1eic acid (ricinoleic acid), oleic acid, linoleic acid, hydrogenated fish oil fatty acids, palm oil fatty acids, cotton seed-oil fatty acids.

The following table shows the results obtained using primary, secondary, tertiary and cycloaliphatic amines and fatty soaps thereof:

primary or secondary amines or the soaps thereof, there may "be used as-the crystallization inhibitor, a heterocyclic nuclear amine of between and 24 carbon atoms per molecule, but, preferably havingbet-ween and18 carbon atoms per molecule. Instead-of using the heterocyclic nuclear amine of the character above set forth, there can be used in lieu thereof a fatty acid soap of the heterocyclic nuclear amine, said amine l soap having between 10 and 28 carbon atoms per molecule.

It is desired to point out that while the present invention is applicable to both lubricating greases containing aluminum di-salts of fatty acid soaps,

5 as for example, aluminum distearate and those containing aluminum'mono-salts of fatty acids, as for example aluminum monostearate. The invention is particularly applicable to those greases which contain the-aluminum mono-salts of fatty acids. As far as known, the prior art aluminum base greases are the aluminum di-salts of fatty acid greases, andnot the aluminum mono-salts of fatty acidgreases. For example, in the trade, when aluminum stearate is referred to it is well understood that what is meant is the aluminum distearate, and not the aluminum monostearate.

- Penetrations Aluminum t Stearate, Bleeding Cracking Texture pemant percent 60 St. 300, St

Aliphatic Amines:

NH 0.5 8 V. S 302 337 0. 8 V. S 295 .328 O. 10 6; 5 V. S- 280 305 .0. 05 6. 3 295 318 0.10 6. 6 300 335 0. l0 5. 5 312 339 0.10 5. 5 332 355 0. l0 5. 5 334 352 0. 10 5. 5 327 359 0. 05 5. 5 340 350 0. l0 5. 5 325 348 -0. 10 5. 5 314 1336 0. 1O 5. 5 313 330 0. l0 5. 5 345 360 (Jr-NH; 0. l0 5. 5 .344 365 Cyclo-Aliphatic Amines:

Di-cyclohexylamine U. 10 5. 5 336 357 Do 0. 06 5. 5

The abbreviations used in the above table are as follows: V. S.Very smooth, does not require milling S.Sm0oth after light milling S. G.Slightly grainy after milling G.-Grai.ny after milling V. SL-Very slight bleeding or cracking S1.Slight bleeding or cracking In one form of the invention a suspension of aluminumstearate in a lubricating oil of 100 to .500 .S. S. U. at 100 F. may be made and the sus- .pensionof aluminum stearate in the oil is heated .to350 F. There is then added to the mixture additional lubricating oil of 100 to 4000, but preferably 100 to 2000 S. S. U. at 100 F., together with 0.05 to 0.30% of an aliphaticprimary or secondary amine containing 5 to 36 carbon atoms per molecule, and preferably 10 to 18 carbon atoms per molecule, the temperature of the resulting mixture being maintained between 310 F. and 350 F. The mixture is then .flowed on to the cooling belt [9 and cooled as a thin quiescent layer to below the transition temperature of the grease in asingle operation to produce a smoothjhomogeneous grease gel. Instead of using an aliphatic, primary orsecondary amine, as set forth in the preceding paragraph, the'fatty acid soaps of the primary or secondary amine may be used, said aliphatic amine soaps containing between 10 and 36 atoms per molecule and preferably, 10 to '23 atoms per molecule, the carbon atoms of the fatty acid being counted as part of the molecule. Instead of using the aliphatic,

The aluminum monostearate greases, when quickly cooled, exhibit a substantially greater tendency to grain, thatis, crystallize and bleed after gelling than do the aluminum distearate greases. It is only usin the present invention .F grams .Preheated coastal red oil of 2000 Vis. at 100" F 5 grams (5%) Polyisobutylene 800'grams Mono-myristyl amine .8 gram (05%) Rosin 1 gram The aluminum monostearate is suspended in 155 grams of the coastal pale oil at room temperature, and the smooth mixture is then heated to about 370 F. until a homogeneous melt is obtained. Thereafter the preheated coastal red oil, the polyisobutylene solution, the mono-myristyl amine, and the rosin are added while the entire mass is kept at about 340 F. The mass is stirred until a homogeneous structure is obtained and the resulting mixture is then poured in a thin layer of about A" to in thickness and exposed to a blast of cool air having a temperature of 80 F., the grease being cooled in accordance with the method herein and in the apparatus herein set forth, the hot grease in its fluid condition being pumped on to the belt I9 of the cooling apparatus. The belt is moved at a speed of approximately feet per minute so that the grease remains on the belt for approximately 15 minutes.

The aluminum soap grease is moved as a quiescent I mass countercurrent tothe air stream.

The resulting grease is a non-bleeding smooth buttery gel. The consistency or ASTM worked penetration of the grease after 60 strokes is 34:6 decimillimeters and after 300 strokes, 367 decimillimeters.

A further example using aluminum monostearate is as follows:

Dodecylethylenediamine 0.8 grams 08% The above grease was cooked and cooled in accordance with the procedure set forth in Example IV except that the time of cooling was minutes. The grease is cooled in a continuous single peration in 20 minutes to a non-bleedin smooth buttery gel having an ASTM worked penetration at 77 F. after 60 strokes of 320 decimillimeters and after 300 strokes, 336 decimillimeters.

The di-N,N' dodecylethylenediamine is:

In the above examples the aluminum monostearate content is 15.61% alumina. It is desired to point out that the aluminum trioxide content, that is the A1203 content of the aluminum monostearate is usually 15%:1%. The aluminum trioxide content, that is the A1203 content of aluminum distearate, is usually 8.1% +1 While in the above specific examples the alumi num monostearate is set forth, it is, of course, obvious that other aluminum salts of other fatty acids may be used, said fatty acids containing up to 32 carbon atoms, but preferably 14 to 2d carbon atoms for the saturated fatty acids. mono aluminum soaps of the saturated fatty acids may be used containing up to 32 carbon atoms and usually from 18 to 22 carbon atoms, as for example, aluminum mono palmitate, and the like. These compounds may also be designated the mono fatty acid salts of aluminum. The generic formula for mo'no fatty acid salts of aluminum then becomes The than when the'di-aluminum soaps of the fatty acids are used.

. In carrying out the present invention, for the dicyclohexylamine there may be substituted monocyclohexylamine. However, the latter is somewhat difiicult to incorporate in the grease because of its low boiling point. 7 a

While the aluminum soap greases can be cooled in successive cooling zones and using different velocities for the cooling medium in the successive cooling zones, it is within the province of the present invention to cool in one zone and use only a single given velocity for the cooling medium.

The amount of polyisobutylene used may vary from 0.3 to 0.5% based on the weight of the grease. When the aluminum soap grease is cooled in successive hot and cold cooling stages the grease in the hot zone may be cooled to a temperature varying between about 200 F. and about 250 F., and the grease in the second cooling zone is then cooled to below the transition temperature of the grease.

All of the above amine crystallization inhibitors may be added in amounts varying between 0.05% to 0.3% based on the total weight of the grease; all of the percentages herein set forth are based on the total weight of the grease. These greases are preferably cooled in thin quiescent layers of 0.10 to 1.0" thickness, but preferably in layers having a thickness varying between 0.20 and 0.40.

I claim:

1. The method comprising forming an aluminum soap grease from a mixture of a mineral oil base having a viscosity of less than 2000 SSU at 11, up to 6% of aluminum monostearate, and 0.05% to 0.3% of a saturated aliphatic amine having 5 to 36 carbon atoms per molecule, feeding the grease in hot fluid condition to a heat conductive moving surface, forming a thin layer of the grease thereon, and cooling the grease while in a quiescent state by subjecting the grease to the action of a gaseous heat absorbing medium until there is produced a smooth substantially homogeneous grease gel.

2. The method comprising forming an aluminum soap grease from a mixture of a mineral oil base having a viscosity of less than 2000 SSU at 100 F., aluminum monostearate, and 0.05% to 0.3% of a saturated aliphatic amine having5 to 36 carbon atoms per molecule, feeding the grease in hot fluid condition to a heat conductive moving surface, forming a thin layer of the grease thereon, and cooling the grease while in a quiescent state by subjecting the grease to the action of a gaseous heat absorbing medium until there is produced a smooth substantially homogeneous grease gel. 7

, 3. The method comprising forming an aluminum soap grease from a mixture 'of a mineral oil base having a viscosity of less than 2000 SSU at 100 R, up to 6% aluminum monostearate, 0.05% to 0.3% of a saturated aliphatic amine having 5 to 36 carbon atoms per molecule, a small amount of rosin sufiicient to aid in thickening and hardening'of the grease, feeding the grease in a hot fluid condition to a heat conductive moving surface, forming a thin layer of the grease thereon, and cooling the grease while in a quiescent state by subjecting the grease to the action of a gaseous heat absorbing medium until there is produced a smooth substantially homogeneous grease gel.

4. The method comprising forming an aluminum soap grease from a mixture of a mineral oil base having a viscosity of less than 2000 SSU at 100 R, up to 6% aluminum monostearate, and 0.05% to 0.3% of a saturated aliphatic amine having to 36 carbon atoms per molecule, a small amount of rosin and about .3% to .5% of polyisobutylene, feeding the grease in a hot fluid condition to a heat conductive moving surface, forming a thin layer of the grease thereon, and cooling the grease while in a quiescent state by subjecting the grease to the action of a gaseous heat absorbing medium until there is produced a smooth substantially homogeneous grease gel.

5. The method of producing an aluminum soap grease containing up to 6% aluminum soap comprising incorporating in the grease 0.05% to 0.3% of a saturated aliphatic amine having more than 5 carbon atoms in the molecule and a small amount suflicient to impart tackiness to said grease of polyisobutylene, feeding the grease in a hot fluid condition to a heat-conductive moving surface, forming a thin layer of grease thereon, and cooling the grease while in a quiescent state by subjecting the grease to the action of a heat absorbing air until there is produced a smooth and homogeneous grease gel.

6. The method comprising forming an aluminum soap grease containing up to 6% of an aluminum soap, from about 0.25% to about 0.5% of polyisobutylene, and from 0.05% to 0.3% of a saturated aliphatic amine having more than 5 carbon atoms in a molecule, feeding the grease in a hot fluid condition to a heat-conductive moving surface, forming a thin layer of grease thereon, and cooling the grease while in a quiescent state by subjecting the grease to the action of a heat absorbing cooling air until there is produced a smooth substantially homogeneous grease gel.

7. The method of producing an aluminum soap grease containing from about 5.5% to about 8% of aluminum soap comprising incorporating in the grease 0.05% to 0.3% of a saturated aliphatic amine having at least 5 carbon atoms in a molecule, feeding the grease in a hot fluid condition to a heat conductive surface, forming a thin layer of grease on said surface and cooling the grease while in a quiescent state in successive hot and cold cooling stages in the presence of a heat absorbing cooling air, the grease in the hot zone being cooled to a temperature varying between 200 to 250 F. and the grease in the second cooling stage being cooled to below the transition temperature of the grease, the ratio of the velocity of flow of the cooling air in the cold stage adjacent the discharge end of the heat conducting surface to the velocity of the cooling air in the hot stage adjacent the intake end of the heat conductive surface varying over the range of 1:1 to 10:1.

8. The method comprising forming an aluminum soap grease from a mixture of a mineral 011 base having a viscosity \of less than 2,000 SSV at R, up to 6% of aluminum distearate, from 0.05% to 0.3% stearylamine and from about 0.3% to 0.5% of polyisobutylene, feeding the grease in hot fluid condition to a heat-conductive moving surface, forming a thin layer of the grease thereon, and cooling the grease while in a quiescent state by subjecting the grease to the action of a gaseous heat-absorbing medium until there is produced a smooth, substantially homogeneous grease gel.

9. The method comprising forming an aluminum soap grease from a mixture of a mineral oil base having a viscosity of less than 2,000 SSV at 100% R, up to 6% of aluminum monostearate, from 0.05% to 0.3% dodecylethylene diamine and from about 0.3% to 0.5% of polyisobutylene, feeding the grease in hot fluid condition to a heat-conductive moving surface, forming a thin layer of the grease thereon, and cooling the grease while in a quiescent state by subjecting the grease to the action of a gaseous heatabsorbing medium until there is produced a smooth, substantially homogeneous grease gel.

ARNOLD A. BONDI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,902,635 Gebhardt Mar. 21, 1933 1,924,211 MacLaren Aug. 29, 1933 2,247,577 Flaxman July 1, 1941 2,339,873 Morway et a1 Jan. 25, 1944 2,374,966 Zimmer May 1, 1945

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